1//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements extra semantic analysis beyond what is enforced
11//  by the C type system.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Sema/SemaInternal.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/CharUnits.h"
18#include "clang/AST/DeclCXX.h"
19#include "clang/AST/DeclObjC.h"
20#include "clang/AST/EvaluatedExprVisitor.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/ExprObjC.h"
24#include "clang/AST/ExprOpenMP.h"
25#include "clang/AST/StmtCXX.h"
26#include "clang/AST/StmtObjC.h"
27#include "clang/Analysis/Analyses/FormatString.h"
28#include "clang/Basic/CharInfo.h"
29#include "clang/Basic/TargetBuiltins.h"
30#include "clang/Basic/TargetInfo.h"
31#include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering.
32#include "clang/Sema/Initialization.h"
33#include "clang/Sema/Lookup.h"
34#include "clang/Sema/ScopeInfo.h"
35#include "clang/Sema/Sema.h"
36#include "llvm/ADT/STLExtras.h"
37#include "llvm/ADT/SmallBitVector.h"
38#include "llvm/ADT/SmallString.h"
39#include "llvm/Support/ConvertUTF.h"
40#include "llvm/Support/raw_ostream.h"
41#include <limits>
42using namespace clang;
43using namespace sema;
44
45SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
46                                                    unsigned ByteNo) const {
47  return SL->getLocationOfByte(ByteNo, getSourceManager(), LangOpts,
48                               Context.getTargetInfo());
49}
50
51/// Checks that a call expression's argument count is the desired number.
52/// This is useful when doing custom type-checking.  Returns true on error.
53static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) {
54  unsigned argCount = call->getNumArgs();
55  if (argCount == desiredArgCount) return false;
56
57  if (argCount < desiredArgCount)
58    return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args)
59        << 0 /*function call*/ << desiredArgCount << argCount
60        << call->getSourceRange();
61
62  // Highlight all the excess arguments.
63  SourceRange range(call->getArg(desiredArgCount)->getLocStart(),
64                    call->getArg(argCount - 1)->getLocEnd());
65
66  return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args)
67    << 0 /*function call*/ << desiredArgCount << argCount
68    << call->getArg(1)->getSourceRange();
69}
70
71/// Check that the first argument to __builtin_annotation is an integer
72/// and the second argument is a non-wide string literal.
73static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) {
74  if (checkArgCount(S, TheCall, 2))
75    return true;
76
77  // First argument should be an integer.
78  Expr *ValArg = TheCall->getArg(0);
79  QualType Ty = ValArg->getType();
80  if (!Ty->isIntegerType()) {
81    S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg)
82      << ValArg->getSourceRange();
83    return true;
84  }
85
86  // Second argument should be a constant string.
87  Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts();
88  StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg);
89  if (!Literal || !Literal->isAscii()) {
90    S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg)
91      << StrArg->getSourceRange();
92    return true;
93  }
94
95  TheCall->setType(Ty);
96  return false;
97}
98
99/// Check that the argument to __builtin_addressof is a glvalue, and set the
100/// result type to the corresponding pointer type.
101static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) {
102  if (checkArgCount(S, TheCall, 1))
103    return true;
104
105  ExprResult Arg(TheCall->getArg(0));
106  QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart());
107  if (ResultType.isNull())
108    return true;
109
110  TheCall->setArg(0, Arg.get());
111  TheCall->setType(ResultType);
112  return false;
113}
114
115static bool SemaBuiltinOverflow(Sema &S, CallExpr *TheCall) {
116  if (checkArgCount(S, TheCall, 3))
117    return true;
118
119  // First two arguments should be integers.
120  for (unsigned I = 0; I < 2; ++I) {
121    Expr *Arg = TheCall->getArg(I);
122    QualType Ty = Arg->getType();
123    if (!Ty->isIntegerType()) {
124      S.Diag(Arg->getLocStart(), diag::err_overflow_builtin_must_be_int)
125          << Ty << Arg->getSourceRange();
126      return true;
127    }
128  }
129
130  // Third argument should be a pointer to a non-const integer.
131  // IRGen correctly handles volatile, restrict, and address spaces, and
132  // the other qualifiers aren't possible.
133  {
134    Expr *Arg = TheCall->getArg(2);
135    QualType Ty = Arg->getType();
136    const auto *PtrTy = Ty->getAs<PointerType>();
137    if (!(PtrTy && PtrTy->getPointeeType()->isIntegerType() &&
138          !PtrTy->getPointeeType().isConstQualified())) {
139      S.Diag(Arg->getLocStart(), diag::err_overflow_builtin_must_be_ptr_int)
140          << Ty << Arg->getSourceRange();
141      return true;
142    }
143  }
144
145  return false;
146}
147
148static void SemaBuiltinMemChkCall(Sema &S, FunctionDecl *FDecl,
149		                  CallExpr *TheCall, unsigned SizeIdx,
150                                  unsigned DstSizeIdx) {
151  if (TheCall->getNumArgs() <= SizeIdx ||
152      TheCall->getNumArgs() <= DstSizeIdx)
153    return;
154
155  const Expr *SizeArg = TheCall->getArg(SizeIdx);
156  const Expr *DstSizeArg = TheCall->getArg(DstSizeIdx);
157
158  llvm::APSInt Size, DstSize;
159
160  // find out if both sizes are known at compile time
161  if (!SizeArg->EvaluateAsInt(Size, S.Context) ||
162      !DstSizeArg->EvaluateAsInt(DstSize, S.Context))
163    return;
164
165  if (Size.ule(DstSize))
166    return;
167
168  // confirmed overflow so generate the diagnostic.
169  IdentifierInfo *FnName = FDecl->getIdentifier();
170  SourceLocation SL = TheCall->getLocStart();
171  SourceRange SR = TheCall->getSourceRange();
172
173  S.Diag(SL, diag::warn_memcpy_chk_overflow) << SR << FnName;
174}
175
176static bool SemaBuiltinCallWithStaticChain(Sema &S, CallExpr *BuiltinCall) {
177  if (checkArgCount(S, BuiltinCall, 2))
178    return true;
179
180  SourceLocation BuiltinLoc = BuiltinCall->getLocStart();
181  Expr *Builtin = BuiltinCall->getCallee()->IgnoreImpCasts();
182  Expr *Call = BuiltinCall->getArg(0);
183  Expr *Chain = BuiltinCall->getArg(1);
184
185  if (Call->getStmtClass() != Stmt::CallExprClass) {
186    S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_not_call)
187        << Call->getSourceRange();
188    return true;
189  }
190
191  auto CE = cast<CallExpr>(Call);
192  if (CE->getCallee()->getType()->isBlockPointerType()) {
193    S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_block_call)
194        << Call->getSourceRange();
195    return true;
196  }
197
198  const Decl *TargetDecl = CE->getCalleeDecl();
199  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl))
200    if (FD->getBuiltinID()) {
201      S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_builtin_call)
202          << Call->getSourceRange();
203      return true;
204    }
205
206  if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens())) {
207    S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_pdtor_call)
208        << Call->getSourceRange();
209    return true;
210  }
211
212  ExprResult ChainResult = S.UsualUnaryConversions(Chain);
213  if (ChainResult.isInvalid())
214    return true;
215  if (!ChainResult.get()->getType()->isPointerType()) {
216    S.Diag(BuiltinLoc, diag::err_second_argument_to_cwsc_not_pointer)
217        << Chain->getSourceRange();
218    return true;
219  }
220
221  QualType ReturnTy = CE->getCallReturnType(S.Context);
222  QualType ArgTys[2] = { ReturnTy, ChainResult.get()->getType() };
223  QualType BuiltinTy = S.Context.getFunctionType(
224      ReturnTy, ArgTys, FunctionProtoType::ExtProtoInfo());
225  QualType BuiltinPtrTy = S.Context.getPointerType(BuiltinTy);
226
227  Builtin =
228      S.ImpCastExprToType(Builtin, BuiltinPtrTy, CK_BuiltinFnToFnPtr).get();
229
230  BuiltinCall->setType(CE->getType());
231  BuiltinCall->setValueKind(CE->getValueKind());
232  BuiltinCall->setObjectKind(CE->getObjectKind());
233  BuiltinCall->setCallee(Builtin);
234  BuiltinCall->setArg(1, ChainResult.get());
235
236  return false;
237}
238
239static bool SemaBuiltinSEHScopeCheck(Sema &SemaRef, CallExpr *TheCall,
240                                     Scope::ScopeFlags NeededScopeFlags,
241                                     unsigned DiagID) {
242  // Scopes aren't available during instantiation. Fortunately, builtin
243  // functions cannot be template args so they cannot be formed through template
244  // instantiation. Therefore checking once during the parse is sufficient.
245  if (!SemaRef.ActiveTemplateInstantiations.empty())
246    return false;
247
248  Scope *S = SemaRef.getCurScope();
249  while (S && !S->isSEHExceptScope())
250    S = S->getParent();
251  if (!S || !(S->getFlags() & NeededScopeFlags)) {
252    auto *DRE = cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
253    SemaRef.Diag(TheCall->getExprLoc(), DiagID)
254        << DRE->getDecl()->getIdentifier();
255    return true;
256  }
257
258  return false;
259}
260
261ExprResult
262Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
263                               CallExpr *TheCall) {
264  ExprResult TheCallResult(TheCall);
265
266  // Find out if any arguments are required to be integer constant expressions.
267  unsigned ICEArguments = 0;
268  ASTContext::GetBuiltinTypeError Error;
269  Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
270  if (Error != ASTContext::GE_None)
271    ICEArguments = 0;  // Don't diagnose previously diagnosed errors.
272
273  // If any arguments are required to be ICE's, check and diagnose.
274  for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
275    // Skip arguments not required to be ICE's.
276    if ((ICEArguments & (1 << ArgNo)) == 0) continue;
277
278    llvm::APSInt Result;
279    if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
280      return true;
281    ICEArguments &= ~(1 << ArgNo);
282  }
283
284  switch (BuiltinID) {
285  case Builtin::BI__builtin___CFStringMakeConstantString:
286    assert(TheCall->getNumArgs() == 1 &&
287           "Wrong # arguments to builtin CFStringMakeConstantString");
288    if (CheckObjCString(TheCall->getArg(0)))
289      return ExprError();
290    break;
291  case Builtin::BI__builtin_stdarg_start:
292  case Builtin::BI__builtin_va_start:
293    if (SemaBuiltinVAStart(TheCall))
294      return ExprError();
295    break;
296  case Builtin::BI__va_start: {
297    switch (Context.getTargetInfo().getTriple().getArch()) {
298    case llvm::Triple::arm:
299    case llvm::Triple::thumb:
300      if (SemaBuiltinVAStartARM(TheCall))
301        return ExprError();
302      break;
303    default:
304      if (SemaBuiltinVAStart(TheCall))
305        return ExprError();
306      break;
307    }
308    break;
309  }
310  case Builtin::BI__builtin_isgreater:
311  case Builtin::BI__builtin_isgreaterequal:
312  case Builtin::BI__builtin_isless:
313  case Builtin::BI__builtin_islessequal:
314  case Builtin::BI__builtin_islessgreater:
315  case Builtin::BI__builtin_isunordered:
316    if (SemaBuiltinUnorderedCompare(TheCall))
317      return ExprError();
318    break;
319  case Builtin::BI__builtin_fpclassify:
320    if (SemaBuiltinFPClassification(TheCall, 6))
321      return ExprError();
322    break;
323  case Builtin::BI__builtin_isfinite:
324  case Builtin::BI__builtin_isinf:
325  case Builtin::BI__builtin_isinf_sign:
326  case Builtin::BI__builtin_isnan:
327  case Builtin::BI__builtin_isnormal:
328    if (SemaBuiltinFPClassification(TheCall, 1))
329      return ExprError();
330    break;
331  case Builtin::BI__builtin_shufflevector:
332    return SemaBuiltinShuffleVector(TheCall);
333    // TheCall will be freed by the smart pointer here, but that's fine, since
334    // SemaBuiltinShuffleVector guts it, but then doesn't release it.
335  case Builtin::BI__builtin_prefetch:
336    if (SemaBuiltinPrefetch(TheCall))
337      return ExprError();
338    break;
339  case Builtin::BI__assume:
340  case Builtin::BI__builtin_assume:
341    if (SemaBuiltinAssume(TheCall))
342      return ExprError();
343    break;
344  case Builtin::BI__builtin_assume_aligned:
345    if (SemaBuiltinAssumeAligned(TheCall))
346      return ExprError();
347    break;
348  case Builtin::BI__builtin_object_size:
349    if (SemaBuiltinConstantArgRange(TheCall, 1, 0, 3))
350      return ExprError();
351    break;
352  case Builtin::BI__builtin_longjmp:
353    if (SemaBuiltinLongjmp(TheCall))
354      return ExprError();
355    break;
356  case Builtin::BI__builtin_setjmp:
357    if (SemaBuiltinSetjmp(TheCall))
358      return ExprError();
359    break;
360  case Builtin::BI_setjmp:
361  case Builtin::BI_setjmpex:
362    if (checkArgCount(*this, TheCall, 1))
363      return true;
364    break;
365
366  case Builtin::BI__builtin_classify_type:
367    if (checkArgCount(*this, TheCall, 1)) return true;
368    TheCall->setType(Context.IntTy);
369    break;
370  case Builtin::BI__builtin_constant_p:
371    if (checkArgCount(*this, TheCall, 1)) return true;
372    TheCall->setType(Context.IntTy);
373    break;
374  case Builtin::BI__sync_fetch_and_add:
375  case Builtin::BI__sync_fetch_and_add_1:
376  case Builtin::BI__sync_fetch_and_add_2:
377  case Builtin::BI__sync_fetch_and_add_4:
378  case Builtin::BI__sync_fetch_and_add_8:
379  case Builtin::BI__sync_fetch_and_add_16:
380  case Builtin::BI__sync_fetch_and_sub:
381  case Builtin::BI__sync_fetch_and_sub_1:
382  case Builtin::BI__sync_fetch_and_sub_2:
383  case Builtin::BI__sync_fetch_and_sub_4:
384  case Builtin::BI__sync_fetch_and_sub_8:
385  case Builtin::BI__sync_fetch_and_sub_16:
386  case Builtin::BI__sync_fetch_and_or:
387  case Builtin::BI__sync_fetch_and_or_1:
388  case Builtin::BI__sync_fetch_and_or_2:
389  case Builtin::BI__sync_fetch_and_or_4:
390  case Builtin::BI__sync_fetch_and_or_8:
391  case Builtin::BI__sync_fetch_and_or_16:
392  case Builtin::BI__sync_fetch_and_and:
393  case Builtin::BI__sync_fetch_and_and_1:
394  case Builtin::BI__sync_fetch_and_and_2:
395  case Builtin::BI__sync_fetch_and_and_4:
396  case Builtin::BI__sync_fetch_and_and_8:
397  case Builtin::BI__sync_fetch_and_and_16:
398  case Builtin::BI__sync_fetch_and_xor:
399  case Builtin::BI__sync_fetch_and_xor_1:
400  case Builtin::BI__sync_fetch_and_xor_2:
401  case Builtin::BI__sync_fetch_and_xor_4:
402  case Builtin::BI__sync_fetch_and_xor_8:
403  case Builtin::BI__sync_fetch_and_xor_16:
404  case Builtin::BI__sync_fetch_and_nand:
405  case Builtin::BI__sync_fetch_and_nand_1:
406  case Builtin::BI__sync_fetch_and_nand_2:
407  case Builtin::BI__sync_fetch_and_nand_4:
408  case Builtin::BI__sync_fetch_and_nand_8:
409  case Builtin::BI__sync_fetch_and_nand_16:
410  case Builtin::BI__sync_add_and_fetch:
411  case Builtin::BI__sync_add_and_fetch_1:
412  case Builtin::BI__sync_add_and_fetch_2:
413  case Builtin::BI__sync_add_and_fetch_4:
414  case Builtin::BI__sync_add_and_fetch_8:
415  case Builtin::BI__sync_add_and_fetch_16:
416  case Builtin::BI__sync_sub_and_fetch:
417  case Builtin::BI__sync_sub_and_fetch_1:
418  case Builtin::BI__sync_sub_and_fetch_2:
419  case Builtin::BI__sync_sub_and_fetch_4:
420  case Builtin::BI__sync_sub_and_fetch_8:
421  case Builtin::BI__sync_sub_and_fetch_16:
422  case Builtin::BI__sync_and_and_fetch:
423  case Builtin::BI__sync_and_and_fetch_1:
424  case Builtin::BI__sync_and_and_fetch_2:
425  case Builtin::BI__sync_and_and_fetch_4:
426  case Builtin::BI__sync_and_and_fetch_8:
427  case Builtin::BI__sync_and_and_fetch_16:
428  case Builtin::BI__sync_or_and_fetch:
429  case Builtin::BI__sync_or_and_fetch_1:
430  case Builtin::BI__sync_or_and_fetch_2:
431  case Builtin::BI__sync_or_and_fetch_4:
432  case Builtin::BI__sync_or_and_fetch_8:
433  case Builtin::BI__sync_or_and_fetch_16:
434  case Builtin::BI__sync_xor_and_fetch:
435  case Builtin::BI__sync_xor_and_fetch_1:
436  case Builtin::BI__sync_xor_and_fetch_2:
437  case Builtin::BI__sync_xor_and_fetch_4:
438  case Builtin::BI__sync_xor_and_fetch_8:
439  case Builtin::BI__sync_xor_and_fetch_16:
440  case Builtin::BI__sync_nand_and_fetch:
441  case Builtin::BI__sync_nand_and_fetch_1:
442  case Builtin::BI__sync_nand_and_fetch_2:
443  case Builtin::BI__sync_nand_and_fetch_4:
444  case Builtin::BI__sync_nand_and_fetch_8:
445  case Builtin::BI__sync_nand_and_fetch_16:
446  case Builtin::BI__sync_val_compare_and_swap:
447  case Builtin::BI__sync_val_compare_and_swap_1:
448  case Builtin::BI__sync_val_compare_and_swap_2:
449  case Builtin::BI__sync_val_compare_and_swap_4:
450  case Builtin::BI__sync_val_compare_and_swap_8:
451  case Builtin::BI__sync_val_compare_and_swap_16:
452  case Builtin::BI__sync_bool_compare_and_swap:
453  case Builtin::BI__sync_bool_compare_and_swap_1:
454  case Builtin::BI__sync_bool_compare_and_swap_2:
455  case Builtin::BI__sync_bool_compare_and_swap_4:
456  case Builtin::BI__sync_bool_compare_and_swap_8:
457  case Builtin::BI__sync_bool_compare_and_swap_16:
458  case Builtin::BI__sync_lock_test_and_set:
459  case Builtin::BI__sync_lock_test_and_set_1:
460  case Builtin::BI__sync_lock_test_and_set_2:
461  case Builtin::BI__sync_lock_test_and_set_4:
462  case Builtin::BI__sync_lock_test_and_set_8:
463  case Builtin::BI__sync_lock_test_and_set_16:
464  case Builtin::BI__sync_lock_release:
465  case Builtin::BI__sync_lock_release_1:
466  case Builtin::BI__sync_lock_release_2:
467  case Builtin::BI__sync_lock_release_4:
468  case Builtin::BI__sync_lock_release_8:
469  case Builtin::BI__sync_lock_release_16:
470  case Builtin::BI__sync_swap:
471  case Builtin::BI__sync_swap_1:
472  case Builtin::BI__sync_swap_2:
473  case Builtin::BI__sync_swap_4:
474  case Builtin::BI__sync_swap_8:
475  case Builtin::BI__sync_swap_16:
476    return SemaBuiltinAtomicOverloaded(TheCallResult);
477  case Builtin::BI__builtin_nontemporal_load:
478  case Builtin::BI__builtin_nontemporal_store:
479    return SemaBuiltinNontemporalOverloaded(TheCallResult);
480#define BUILTIN(ID, TYPE, ATTRS)
481#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \
482  case Builtin::BI##ID: \
483    return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID);
484#include "clang/Basic/Builtins.def"
485  case Builtin::BI__builtin_annotation:
486    if (SemaBuiltinAnnotation(*this, TheCall))
487      return ExprError();
488    break;
489  case Builtin::BI__builtin_addressof:
490    if (SemaBuiltinAddressof(*this, TheCall))
491      return ExprError();
492    break;
493  case Builtin::BI__builtin_add_overflow:
494  case Builtin::BI__builtin_sub_overflow:
495  case Builtin::BI__builtin_mul_overflow:
496    if (SemaBuiltinOverflow(*this, TheCall))
497      return ExprError();
498    break;
499  case Builtin::BI__builtin_operator_new:
500  case Builtin::BI__builtin_operator_delete:
501    if (!getLangOpts().CPlusPlus) {
502      Diag(TheCall->getExprLoc(), diag::err_builtin_requires_language)
503        << (BuiltinID == Builtin::BI__builtin_operator_new
504                ? "__builtin_operator_new"
505                : "__builtin_operator_delete")
506        << "C++";
507      return ExprError();
508    }
509    // CodeGen assumes it can find the global new and delete to call,
510    // so ensure that they are declared.
511    DeclareGlobalNewDelete();
512    break;
513
514  // check secure string manipulation functions where overflows
515  // are detectable at compile time
516  case Builtin::BI__builtin___memcpy_chk:
517  case Builtin::BI__builtin___memmove_chk:
518  case Builtin::BI__builtin___memset_chk:
519  case Builtin::BI__builtin___strlcat_chk:
520  case Builtin::BI__builtin___strlcpy_chk:
521  case Builtin::BI__builtin___strncat_chk:
522  case Builtin::BI__builtin___strncpy_chk:
523  case Builtin::BI__builtin___stpncpy_chk:
524    SemaBuiltinMemChkCall(*this, FDecl, TheCall, 2, 3);
525    break;
526  case Builtin::BI__builtin___memccpy_chk:
527    SemaBuiltinMemChkCall(*this, FDecl, TheCall, 3, 4);
528    break;
529  case Builtin::BI__builtin___snprintf_chk:
530  case Builtin::BI__builtin___vsnprintf_chk:
531    SemaBuiltinMemChkCall(*this, FDecl, TheCall, 1, 3);
532    break;
533
534  case Builtin::BI__builtin_call_with_static_chain:
535    if (SemaBuiltinCallWithStaticChain(*this, TheCall))
536      return ExprError();
537    break;
538
539  case Builtin::BI__exception_code:
540  case Builtin::BI_exception_code: {
541    if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHExceptScope,
542                                 diag::err_seh___except_block))
543      return ExprError();
544    break;
545  }
546  case Builtin::BI__exception_info:
547  case Builtin::BI_exception_info: {
548    if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHFilterScope,
549                                 diag::err_seh___except_filter))
550      return ExprError();
551    break;
552  }
553
554  case Builtin::BI__GetExceptionInfo:
555    if (checkArgCount(*this, TheCall, 1))
556      return ExprError();
557
558    if (CheckCXXThrowOperand(
559            TheCall->getLocStart(),
560            Context.getExceptionObjectType(FDecl->getParamDecl(0)->getType()),
561            TheCall))
562      return ExprError();
563
564    TheCall->setType(Context.VoidPtrTy);
565    break;
566
567  }
568
569  // Since the target specific builtins for each arch overlap, only check those
570  // of the arch we are compiling for.
571  if (Context.BuiltinInfo.isTSBuiltin(BuiltinID)) {
572    switch (Context.getTargetInfo().getTriple().getArch()) {
573      case llvm::Triple::arm:
574      case llvm::Triple::armeb:
575      case llvm::Triple::thumb:
576      case llvm::Triple::thumbeb:
577        if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
578          return ExprError();
579        break;
580      case llvm::Triple::aarch64:
581      case llvm::Triple::aarch64_be:
582        if (CheckAArch64BuiltinFunctionCall(BuiltinID, TheCall))
583          return ExprError();
584        break;
585      case llvm::Triple::mips:
586      case llvm::Triple::mipsel:
587      case llvm::Triple::mips64:
588      case llvm::Triple::mips64el:
589        if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall))
590          return ExprError();
591        break;
592      case llvm::Triple::systemz:
593        if (CheckSystemZBuiltinFunctionCall(BuiltinID, TheCall))
594          return ExprError();
595        break;
596      case llvm::Triple::x86:
597      case llvm::Triple::x86_64:
598        if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall))
599          return ExprError();
600        break;
601      case llvm::Triple::ppc:
602      case llvm::Triple::ppc64:
603      case llvm::Triple::ppc64le:
604        if (CheckPPCBuiltinFunctionCall(BuiltinID, TheCall))
605          return ExprError();
606        break;
607      default:
608        break;
609    }
610  }
611
612  return TheCallResult;
613}
614
615// Get the valid immediate range for the specified NEON type code.
616static unsigned RFT(unsigned t, bool shift = false, bool ForceQuad = false) {
617  NeonTypeFlags Type(t);
618  int IsQuad = ForceQuad ? true : Type.isQuad();
619  switch (Type.getEltType()) {
620  case NeonTypeFlags::Int8:
621  case NeonTypeFlags::Poly8:
622    return shift ? 7 : (8 << IsQuad) - 1;
623  case NeonTypeFlags::Int16:
624  case NeonTypeFlags::Poly16:
625    return shift ? 15 : (4 << IsQuad) - 1;
626  case NeonTypeFlags::Int32:
627    return shift ? 31 : (2 << IsQuad) - 1;
628  case NeonTypeFlags::Int64:
629  case NeonTypeFlags::Poly64:
630    return shift ? 63 : (1 << IsQuad) - 1;
631  case NeonTypeFlags::Poly128:
632    return shift ? 127 : (1 << IsQuad) - 1;
633  case NeonTypeFlags::Float16:
634    assert(!shift && "cannot shift float types!");
635    return (4 << IsQuad) - 1;
636  case NeonTypeFlags::Float32:
637    assert(!shift && "cannot shift float types!");
638    return (2 << IsQuad) - 1;
639  case NeonTypeFlags::Float64:
640    assert(!shift && "cannot shift float types!");
641    return (1 << IsQuad) - 1;
642  }
643  llvm_unreachable("Invalid NeonTypeFlag!");
644}
645
646/// getNeonEltType - Return the QualType corresponding to the elements of
647/// the vector type specified by the NeonTypeFlags.  This is used to check
648/// the pointer arguments for Neon load/store intrinsics.
649static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context,
650                               bool IsPolyUnsigned, bool IsInt64Long) {
651  switch (Flags.getEltType()) {
652  case NeonTypeFlags::Int8:
653    return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
654  case NeonTypeFlags::Int16:
655    return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
656  case NeonTypeFlags::Int32:
657    return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
658  case NeonTypeFlags::Int64:
659    if (IsInt64Long)
660      return Flags.isUnsigned() ? Context.UnsignedLongTy : Context.LongTy;
661    else
662      return Flags.isUnsigned() ? Context.UnsignedLongLongTy
663                                : Context.LongLongTy;
664  case NeonTypeFlags::Poly8:
665    return IsPolyUnsigned ? Context.UnsignedCharTy : Context.SignedCharTy;
666  case NeonTypeFlags::Poly16:
667    return IsPolyUnsigned ? Context.UnsignedShortTy : Context.ShortTy;
668  case NeonTypeFlags::Poly64:
669    if (IsInt64Long)
670      return Context.UnsignedLongTy;
671    else
672      return Context.UnsignedLongLongTy;
673  case NeonTypeFlags::Poly128:
674    break;
675  case NeonTypeFlags::Float16:
676    return Context.HalfTy;
677  case NeonTypeFlags::Float32:
678    return Context.FloatTy;
679  case NeonTypeFlags::Float64:
680    return Context.DoubleTy;
681  }
682  llvm_unreachable("Invalid NeonTypeFlag!");
683}
684
685bool Sema::CheckNeonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
686  llvm::APSInt Result;
687  uint64_t mask = 0;
688  unsigned TV = 0;
689  int PtrArgNum = -1;
690  bool HasConstPtr = false;
691  switch (BuiltinID) {
692#define GET_NEON_OVERLOAD_CHECK
693#include "clang/Basic/arm_neon.inc"
694#undef GET_NEON_OVERLOAD_CHECK
695  }
696
697  // For NEON intrinsics which are overloaded on vector element type, validate
698  // the immediate which specifies which variant to emit.
699  unsigned ImmArg = TheCall->getNumArgs()-1;
700  if (mask) {
701    if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
702      return true;
703
704    TV = Result.getLimitedValue(64);
705    if ((TV > 63) || (mask & (1ULL << TV)) == 0)
706      return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
707        << TheCall->getArg(ImmArg)->getSourceRange();
708  }
709
710  if (PtrArgNum >= 0) {
711    // Check that pointer arguments have the specified type.
712    Expr *Arg = TheCall->getArg(PtrArgNum);
713    if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
714      Arg = ICE->getSubExpr();
715    ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
716    QualType RHSTy = RHS.get()->getType();
717
718    llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
719    bool IsPolyUnsigned = Arch == llvm::Triple::aarch64;
720    bool IsInt64Long =
721        Context.getTargetInfo().getInt64Type() == TargetInfo::SignedLong;
722    QualType EltTy =
723        getNeonEltType(NeonTypeFlags(TV), Context, IsPolyUnsigned, IsInt64Long);
724    if (HasConstPtr)
725      EltTy = EltTy.withConst();
726    QualType LHSTy = Context.getPointerType(EltTy);
727    AssignConvertType ConvTy;
728    ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
729    if (RHS.isInvalid())
730      return true;
731    if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
732                                 RHS.get(), AA_Assigning))
733      return true;
734  }
735
736  // For NEON intrinsics which take an immediate value as part of the
737  // instruction, range check them here.
738  unsigned i = 0, l = 0, u = 0;
739  switch (BuiltinID) {
740  default:
741    return false;
742#define GET_NEON_IMMEDIATE_CHECK
743#include "clang/Basic/arm_neon.inc"
744#undef GET_NEON_IMMEDIATE_CHECK
745  }
746
747  return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
748}
749
750bool Sema::CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall,
751                                        unsigned MaxWidth) {
752  assert((BuiltinID == ARM::BI__builtin_arm_ldrex ||
753          BuiltinID == ARM::BI__builtin_arm_ldaex ||
754          BuiltinID == ARM::BI__builtin_arm_strex ||
755          BuiltinID == ARM::BI__builtin_arm_stlex ||
756          BuiltinID == AArch64::BI__builtin_arm_ldrex ||
757          BuiltinID == AArch64::BI__builtin_arm_ldaex ||
758          BuiltinID == AArch64::BI__builtin_arm_strex ||
759          BuiltinID == AArch64::BI__builtin_arm_stlex) &&
760         "unexpected ARM builtin");
761  bool IsLdrex = BuiltinID == ARM::BI__builtin_arm_ldrex ||
762                 BuiltinID == ARM::BI__builtin_arm_ldaex ||
763                 BuiltinID == AArch64::BI__builtin_arm_ldrex ||
764                 BuiltinID == AArch64::BI__builtin_arm_ldaex;
765
766  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
767
768  // Ensure that we have the proper number of arguments.
769  if (checkArgCount(*this, TheCall, IsLdrex ? 1 : 2))
770    return true;
771
772  // Inspect the pointer argument of the atomic builtin.  This should always be
773  // a pointer type, whose element is an integral scalar or pointer type.
774  // Because it is a pointer type, we don't have to worry about any implicit
775  // casts here.
776  Expr *PointerArg = TheCall->getArg(IsLdrex ? 0 : 1);
777  ExprResult PointerArgRes = DefaultFunctionArrayLvalueConversion(PointerArg);
778  if (PointerArgRes.isInvalid())
779    return true;
780  PointerArg = PointerArgRes.get();
781
782  const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>();
783  if (!pointerType) {
784    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
785      << PointerArg->getType() << PointerArg->getSourceRange();
786    return true;
787  }
788
789  // ldrex takes a "const volatile T*" and strex takes a "volatile T*". Our next
790  // task is to insert the appropriate casts into the AST. First work out just
791  // what the appropriate type is.
792  QualType ValType = pointerType->getPointeeType();
793  QualType AddrType = ValType.getUnqualifiedType().withVolatile();
794  if (IsLdrex)
795    AddrType.addConst();
796
797  // Issue a warning if the cast is dodgy.
798  CastKind CastNeeded = CK_NoOp;
799  if (!AddrType.isAtLeastAsQualifiedAs(ValType)) {
800    CastNeeded = CK_BitCast;
801    Diag(DRE->getLocStart(), diag::ext_typecheck_convert_discards_qualifiers)
802      << PointerArg->getType()
803      << Context.getPointerType(AddrType)
804      << AA_Passing << PointerArg->getSourceRange();
805  }
806
807  // Finally, do the cast and replace the argument with the corrected version.
808  AddrType = Context.getPointerType(AddrType);
809  PointerArgRes = ImpCastExprToType(PointerArg, AddrType, CastNeeded);
810  if (PointerArgRes.isInvalid())
811    return true;
812  PointerArg = PointerArgRes.get();
813
814  TheCall->setArg(IsLdrex ? 0 : 1, PointerArg);
815
816  // In general, we allow ints, floats and pointers to be loaded and stored.
817  if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
818      !ValType->isBlockPointerType() && !ValType->isFloatingType()) {
819    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intfltptr)
820      << PointerArg->getType() << PointerArg->getSourceRange();
821    return true;
822  }
823
824  // But ARM doesn't have instructions to deal with 128-bit versions.
825  if (Context.getTypeSize(ValType) > MaxWidth) {
826    assert(MaxWidth == 64 && "Diagnostic unexpectedly inaccurate");
827    Diag(DRE->getLocStart(), diag::err_atomic_exclusive_builtin_pointer_size)
828      << PointerArg->getType() << PointerArg->getSourceRange();
829    return true;
830  }
831
832  switch (ValType.getObjCLifetime()) {
833  case Qualifiers::OCL_None:
834  case Qualifiers::OCL_ExplicitNone:
835    // okay
836    break;
837
838  case Qualifiers::OCL_Weak:
839  case Qualifiers::OCL_Strong:
840  case Qualifiers::OCL_Autoreleasing:
841    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
842      << ValType << PointerArg->getSourceRange();
843    return true;
844  }
845
846
847  if (IsLdrex) {
848    TheCall->setType(ValType);
849    return false;
850  }
851
852  // Initialize the argument to be stored.
853  ExprResult ValArg = TheCall->getArg(0);
854  InitializedEntity Entity = InitializedEntity::InitializeParameter(
855      Context, ValType, /*consume*/ false);
856  ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg);
857  if (ValArg.isInvalid())
858    return true;
859  TheCall->setArg(0, ValArg.get());
860
861  // __builtin_arm_strex always returns an int. It's marked as such in the .def,
862  // but the custom checker bypasses all default analysis.
863  TheCall->setType(Context.IntTy);
864  return false;
865}
866
867bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
868  llvm::APSInt Result;
869
870  if (BuiltinID == ARM::BI__builtin_arm_ldrex ||
871      BuiltinID == ARM::BI__builtin_arm_ldaex ||
872      BuiltinID == ARM::BI__builtin_arm_strex ||
873      BuiltinID == ARM::BI__builtin_arm_stlex) {
874    return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 64);
875  }
876
877  if (BuiltinID == ARM::BI__builtin_arm_prefetch) {
878    return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) ||
879      SemaBuiltinConstantArgRange(TheCall, 2, 0, 1);
880  }
881
882  if (BuiltinID == ARM::BI__builtin_arm_rsr64 ||
883      BuiltinID == ARM::BI__builtin_arm_wsr64)
884    return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 3, false);
885
886  if (BuiltinID == ARM::BI__builtin_arm_rsr ||
887      BuiltinID == ARM::BI__builtin_arm_rsrp ||
888      BuiltinID == ARM::BI__builtin_arm_wsr ||
889      BuiltinID == ARM::BI__builtin_arm_wsrp)
890    return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true);
891
892  if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall))
893    return true;
894
895  // For intrinsics which take an immediate value as part of the instruction,
896  // range check them here.
897  unsigned i = 0, l = 0, u = 0;
898  switch (BuiltinID) {
899  default: return false;
900  case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
901  case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
902  case ARM::BI__builtin_arm_vcvtr_f:
903  case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
904  case ARM::BI__builtin_arm_dmb:
905  case ARM::BI__builtin_arm_dsb:
906  case ARM::BI__builtin_arm_isb:
907  case ARM::BI__builtin_arm_dbg: l = 0; u = 15; break;
908  }
909
910  // FIXME: VFP Intrinsics should error if VFP not present.
911  return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
912}
913
914bool Sema::CheckAArch64BuiltinFunctionCall(unsigned BuiltinID,
915                                         CallExpr *TheCall) {
916  llvm::APSInt Result;
917
918  if (BuiltinID == AArch64::BI__builtin_arm_ldrex ||
919      BuiltinID == AArch64::BI__builtin_arm_ldaex ||
920      BuiltinID == AArch64::BI__builtin_arm_strex ||
921      BuiltinID == AArch64::BI__builtin_arm_stlex) {
922    return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 128);
923  }
924
925  if (BuiltinID == AArch64::BI__builtin_arm_prefetch) {
926    return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) ||
927      SemaBuiltinConstantArgRange(TheCall, 2, 0, 2) ||
928      SemaBuiltinConstantArgRange(TheCall, 3, 0, 1) ||
929      SemaBuiltinConstantArgRange(TheCall, 4, 0, 1);
930  }
931
932  if (BuiltinID == AArch64::BI__builtin_arm_rsr64 ||
933      BuiltinID == AArch64::BI__builtin_arm_wsr64)
934    return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, false);
935
936  if (BuiltinID == AArch64::BI__builtin_arm_rsr ||
937      BuiltinID == AArch64::BI__builtin_arm_rsrp ||
938      BuiltinID == AArch64::BI__builtin_arm_wsr ||
939      BuiltinID == AArch64::BI__builtin_arm_wsrp)
940    return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true);
941
942  if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall))
943    return true;
944
945  // For intrinsics which take an immediate value as part of the instruction,
946  // range check them here.
947  unsigned i = 0, l = 0, u = 0;
948  switch (BuiltinID) {
949  default: return false;
950  case AArch64::BI__builtin_arm_dmb:
951  case AArch64::BI__builtin_arm_dsb:
952  case AArch64::BI__builtin_arm_isb: l = 0; u = 15; break;
953  }
954
955  return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
956}
957
958bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
959  unsigned i = 0, l = 0, u = 0;
960  switch (BuiltinID) {
961  default: return false;
962  case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break;
963  case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break;
964  case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break;
965  case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break;
966  case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break;
967  case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break;
968  case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break;
969  }
970
971  return SemaBuiltinConstantArgRange(TheCall, i, l, u);
972}
973
974bool Sema::CheckPPCBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
975  unsigned i = 0, l = 0, u = 0;
976  bool Is64BitBltin = BuiltinID == PPC::BI__builtin_divde ||
977                      BuiltinID == PPC::BI__builtin_divdeu ||
978                      BuiltinID == PPC::BI__builtin_bpermd;
979  bool IsTarget64Bit = Context.getTargetInfo()
980                              .getTypeWidth(Context
981                                            .getTargetInfo()
982                                            .getIntPtrType()) == 64;
983  bool IsBltinExtDiv = BuiltinID == PPC::BI__builtin_divwe ||
984                       BuiltinID == PPC::BI__builtin_divweu ||
985                       BuiltinID == PPC::BI__builtin_divde ||
986                       BuiltinID == PPC::BI__builtin_divdeu;
987
988  if (Is64BitBltin && !IsTarget64Bit)
989      return Diag(TheCall->getLocStart(), diag::err_64_bit_builtin_32_bit_tgt)
990             << TheCall->getSourceRange();
991
992  if ((IsBltinExtDiv && !Context.getTargetInfo().hasFeature("extdiv")) ||
993      (BuiltinID == PPC::BI__builtin_bpermd &&
994       !Context.getTargetInfo().hasFeature("bpermd")))
995    return Diag(TheCall->getLocStart(), diag::err_ppc_builtin_only_on_pwr7)
996           << TheCall->getSourceRange();
997
998  switch (BuiltinID) {
999  default: return false;
1000  case PPC::BI__builtin_altivec_crypto_vshasigmaw:
1001  case PPC::BI__builtin_altivec_crypto_vshasigmad:
1002    return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) ||
1003           SemaBuiltinConstantArgRange(TheCall, 2, 0, 15);
1004  case PPC::BI__builtin_tbegin:
1005  case PPC::BI__builtin_tend: i = 0; l = 0; u = 1; break;
1006  case PPC::BI__builtin_tsr: i = 0; l = 0; u = 7; break;
1007  case PPC::BI__builtin_tabortwc:
1008  case PPC::BI__builtin_tabortdc: i = 0; l = 0; u = 31; break;
1009  case PPC::BI__builtin_tabortwci:
1010  case PPC::BI__builtin_tabortdci:
1011    return SemaBuiltinConstantArgRange(TheCall, 0, 0, 31) ||
1012           SemaBuiltinConstantArgRange(TheCall, 2, 0, 31);
1013  }
1014  return SemaBuiltinConstantArgRange(TheCall, i, l, u);
1015}
1016
1017bool Sema::CheckSystemZBuiltinFunctionCall(unsigned BuiltinID,
1018                                           CallExpr *TheCall) {
1019  if (BuiltinID == SystemZ::BI__builtin_tabort) {
1020    Expr *Arg = TheCall->getArg(0);
1021    llvm::APSInt AbortCode(32);
1022    if (Arg->isIntegerConstantExpr(AbortCode, Context) &&
1023        AbortCode.getSExtValue() >= 0 && AbortCode.getSExtValue() < 256)
1024      return Diag(Arg->getLocStart(), diag::err_systemz_invalid_tabort_code)
1025             << Arg->getSourceRange();
1026  }
1027
1028  // For intrinsics which take an immediate value as part of the instruction,
1029  // range check them here.
1030  unsigned i = 0, l = 0, u = 0;
1031  switch (BuiltinID) {
1032  default: return false;
1033  case SystemZ::BI__builtin_s390_lcbb: i = 1; l = 0; u = 15; break;
1034  case SystemZ::BI__builtin_s390_verimb:
1035  case SystemZ::BI__builtin_s390_verimh:
1036  case SystemZ::BI__builtin_s390_verimf:
1037  case SystemZ::BI__builtin_s390_verimg: i = 3; l = 0; u = 255; break;
1038  case SystemZ::BI__builtin_s390_vfaeb:
1039  case SystemZ::BI__builtin_s390_vfaeh:
1040  case SystemZ::BI__builtin_s390_vfaef:
1041  case SystemZ::BI__builtin_s390_vfaebs:
1042  case SystemZ::BI__builtin_s390_vfaehs:
1043  case SystemZ::BI__builtin_s390_vfaefs:
1044  case SystemZ::BI__builtin_s390_vfaezb:
1045  case SystemZ::BI__builtin_s390_vfaezh:
1046  case SystemZ::BI__builtin_s390_vfaezf:
1047  case SystemZ::BI__builtin_s390_vfaezbs:
1048  case SystemZ::BI__builtin_s390_vfaezhs:
1049  case SystemZ::BI__builtin_s390_vfaezfs: i = 2; l = 0; u = 15; break;
1050  case SystemZ::BI__builtin_s390_vfidb:
1051    return SemaBuiltinConstantArgRange(TheCall, 1, 0, 15) ||
1052           SemaBuiltinConstantArgRange(TheCall, 2, 0, 15);
1053  case SystemZ::BI__builtin_s390_vftcidb: i = 1; l = 0; u = 4095; break;
1054  case SystemZ::BI__builtin_s390_vlbb: i = 1; l = 0; u = 15; break;
1055  case SystemZ::BI__builtin_s390_vpdi: i = 2; l = 0; u = 15; break;
1056  case SystemZ::BI__builtin_s390_vsldb: i = 2; l = 0; u = 15; break;
1057  case SystemZ::BI__builtin_s390_vstrcb:
1058  case SystemZ::BI__builtin_s390_vstrch:
1059  case SystemZ::BI__builtin_s390_vstrcf:
1060  case SystemZ::BI__builtin_s390_vstrczb:
1061  case SystemZ::BI__builtin_s390_vstrczh:
1062  case SystemZ::BI__builtin_s390_vstrczf:
1063  case SystemZ::BI__builtin_s390_vstrcbs:
1064  case SystemZ::BI__builtin_s390_vstrchs:
1065  case SystemZ::BI__builtin_s390_vstrcfs:
1066  case SystemZ::BI__builtin_s390_vstrczbs:
1067  case SystemZ::BI__builtin_s390_vstrczhs:
1068  case SystemZ::BI__builtin_s390_vstrczfs: i = 3; l = 0; u = 15; break;
1069  }
1070  return SemaBuiltinConstantArgRange(TheCall, i, l, u);
1071}
1072
1073/// SemaBuiltinCpuSupports - Handle __builtin_cpu_supports(char *).
1074/// This checks that the target supports __builtin_cpu_supports and
1075/// that the string argument is constant and valid.
1076static bool SemaBuiltinCpuSupports(Sema &S, CallExpr *TheCall) {
1077  Expr *Arg = TheCall->getArg(0);
1078
1079  // Check if the argument is a string literal.
1080  if (!isa<StringLiteral>(Arg->IgnoreParenImpCasts()))
1081    return S.Diag(TheCall->getLocStart(), diag::err_expr_not_string_literal)
1082           << Arg->getSourceRange();
1083
1084  // Check the contents of the string.
1085  StringRef Feature =
1086      cast<StringLiteral>(Arg->IgnoreParenImpCasts())->getString();
1087  if (!S.Context.getTargetInfo().validateCpuSupports(Feature))
1088    return S.Diag(TheCall->getLocStart(), diag::err_invalid_cpu_supports)
1089           << Arg->getSourceRange();
1090  return false;
1091}
1092
1093bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
1094  unsigned i = 0, l = 0, u = 0;
1095  switch (BuiltinID) {
1096  default: return false;
1097  case X86::BI__builtin_cpu_supports:
1098    return SemaBuiltinCpuSupports(*this, TheCall);
1099  case X86::BI__builtin_ms_va_start:
1100    return SemaBuiltinMSVAStart(TheCall);
1101  case X86::BI_mm_prefetch: i = 1; l = 0; u = 3; break;
1102  case X86::BI__builtin_ia32_sha1rnds4: i = 2, l = 0; u = 3; break;
1103  case X86::BI__builtin_ia32_vpermil2pd:
1104  case X86::BI__builtin_ia32_vpermil2pd256:
1105  case X86::BI__builtin_ia32_vpermil2ps:
1106  case X86::BI__builtin_ia32_vpermil2ps256: i = 3, l = 0; u = 3; break;
1107  case X86::BI__builtin_ia32_cmpb128_mask:
1108  case X86::BI__builtin_ia32_cmpw128_mask:
1109  case X86::BI__builtin_ia32_cmpd128_mask:
1110  case X86::BI__builtin_ia32_cmpq128_mask:
1111  case X86::BI__builtin_ia32_cmpb256_mask:
1112  case X86::BI__builtin_ia32_cmpw256_mask:
1113  case X86::BI__builtin_ia32_cmpd256_mask:
1114  case X86::BI__builtin_ia32_cmpq256_mask:
1115  case X86::BI__builtin_ia32_cmpb512_mask:
1116  case X86::BI__builtin_ia32_cmpw512_mask:
1117  case X86::BI__builtin_ia32_cmpd512_mask:
1118  case X86::BI__builtin_ia32_cmpq512_mask:
1119  case X86::BI__builtin_ia32_ucmpb128_mask:
1120  case X86::BI__builtin_ia32_ucmpw128_mask:
1121  case X86::BI__builtin_ia32_ucmpd128_mask:
1122  case X86::BI__builtin_ia32_ucmpq128_mask:
1123  case X86::BI__builtin_ia32_ucmpb256_mask:
1124  case X86::BI__builtin_ia32_ucmpw256_mask:
1125  case X86::BI__builtin_ia32_ucmpd256_mask:
1126  case X86::BI__builtin_ia32_ucmpq256_mask:
1127  case X86::BI__builtin_ia32_ucmpb512_mask:
1128  case X86::BI__builtin_ia32_ucmpw512_mask:
1129  case X86::BI__builtin_ia32_ucmpd512_mask:
1130  case X86::BI__builtin_ia32_ucmpq512_mask: i = 2; l = 0; u = 7; break;
1131  case X86::BI__builtin_ia32_roundps:
1132  case X86::BI__builtin_ia32_roundpd:
1133  case X86::BI__builtin_ia32_roundps256:
1134  case X86::BI__builtin_ia32_roundpd256: i = 1, l = 0; u = 15; break;
1135  case X86::BI__builtin_ia32_roundss:
1136  case X86::BI__builtin_ia32_roundsd: i = 2, l = 0; u = 15; break;
1137  case X86::BI__builtin_ia32_cmpps:
1138  case X86::BI__builtin_ia32_cmpss:
1139  case X86::BI__builtin_ia32_cmppd:
1140  case X86::BI__builtin_ia32_cmpsd:
1141  case X86::BI__builtin_ia32_cmpps256:
1142  case X86::BI__builtin_ia32_cmppd256:
1143  case X86::BI__builtin_ia32_cmpps512_mask:
1144  case X86::BI__builtin_ia32_cmppd512_mask: i = 2; l = 0; u = 31; break;
1145  case X86::BI__builtin_ia32_vpcomub:
1146  case X86::BI__builtin_ia32_vpcomuw:
1147  case X86::BI__builtin_ia32_vpcomud:
1148  case X86::BI__builtin_ia32_vpcomuq:
1149  case X86::BI__builtin_ia32_vpcomb:
1150  case X86::BI__builtin_ia32_vpcomw:
1151  case X86::BI__builtin_ia32_vpcomd:
1152  case X86::BI__builtin_ia32_vpcomq: i = 2; l = 0; u = 7; break;
1153  }
1154  return SemaBuiltinConstantArgRange(TheCall, i, l, u);
1155}
1156
1157/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo
1158/// parameter with the FormatAttr's correct format_idx and firstDataArg.
1159/// Returns true when the format fits the function and the FormatStringInfo has
1160/// been populated.
1161bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
1162                               FormatStringInfo *FSI) {
1163  FSI->HasVAListArg = Format->getFirstArg() == 0;
1164  FSI->FormatIdx = Format->getFormatIdx() - 1;
1165  FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1;
1166
1167  // The way the format attribute works in GCC, the implicit this argument
1168  // of member functions is counted. However, it doesn't appear in our own
1169  // lists, so decrement format_idx in that case.
1170  if (IsCXXMember) {
1171    if(FSI->FormatIdx == 0)
1172      return false;
1173    --FSI->FormatIdx;
1174    if (FSI->FirstDataArg != 0)
1175      --FSI->FirstDataArg;
1176  }
1177  return true;
1178}
1179
1180/// Checks if a the given expression evaluates to null.
1181///
1182/// \brief Returns true if the value evaluates to null.
1183static bool CheckNonNullExpr(Sema &S, const Expr *Expr) {
1184  // If the expression has non-null type, it doesn't evaluate to null.
1185  if (auto nullability
1186        = Expr->IgnoreImplicit()->getType()->getNullability(S.Context)) {
1187    if (*nullability == NullabilityKind::NonNull)
1188      return false;
1189  }
1190
1191  // As a special case, transparent unions initialized with zero are
1192  // considered null for the purposes of the nonnull attribute.
1193  if (const RecordType *UT = Expr->getType()->getAsUnionType()) {
1194    if (UT->getDecl()->hasAttr<TransparentUnionAttr>())
1195      if (const CompoundLiteralExpr *CLE =
1196          dyn_cast<CompoundLiteralExpr>(Expr))
1197        if (const InitListExpr *ILE =
1198            dyn_cast<InitListExpr>(CLE->getInitializer()))
1199          Expr = ILE->getInit(0);
1200  }
1201
1202  bool Result;
1203  return (!Expr->isValueDependent() &&
1204          Expr->EvaluateAsBooleanCondition(Result, S.Context) &&
1205          !Result);
1206}
1207
1208static void CheckNonNullArgument(Sema &S,
1209                                 const Expr *ArgExpr,
1210                                 SourceLocation CallSiteLoc) {
1211  if (CheckNonNullExpr(S, ArgExpr))
1212    S.DiagRuntimeBehavior(CallSiteLoc, ArgExpr,
1213           S.PDiag(diag::warn_null_arg) << ArgExpr->getSourceRange());
1214}
1215
1216bool Sema::GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx) {
1217  FormatStringInfo FSI;
1218  if ((GetFormatStringType(Format) == FST_NSString) &&
1219      getFormatStringInfo(Format, false, &FSI)) {
1220    Idx = FSI.FormatIdx;
1221    return true;
1222  }
1223  return false;
1224}
1225/// \brief Diagnose use of %s directive in an NSString which is being passed
1226/// as formatting string to formatting method.
1227static void
1228DiagnoseCStringFormatDirectiveInCFAPI(Sema &S,
1229                                        const NamedDecl *FDecl,
1230                                        Expr **Args,
1231                                        unsigned NumArgs) {
1232  unsigned Idx = 0;
1233  bool Format = false;
1234  ObjCStringFormatFamily SFFamily = FDecl->getObjCFStringFormattingFamily();
1235  if (SFFamily == ObjCStringFormatFamily::SFF_CFString) {
1236    Idx = 2;
1237    Format = true;
1238  }
1239  else
1240    for (const auto *I : FDecl->specific_attrs<FormatAttr>()) {
1241      if (S.GetFormatNSStringIdx(I, Idx)) {
1242        Format = true;
1243        break;
1244      }
1245    }
1246  if (!Format || NumArgs <= Idx)
1247    return;
1248  const Expr *FormatExpr = Args[Idx];
1249  if (const CStyleCastExpr *CSCE = dyn_cast<CStyleCastExpr>(FormatExpr))
1250    FormatExpr = CSCE->getSubExpr();
1251  const StringLiteral *FormatString;
1252  if (const ObjCStringLiteral *OSL =
1253      dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts()))
1254    FormatString = OSL->getString();
1255  else
1256    FormatString = dyn_cast<StringLiteral>(FormatExpr->IgnoreParenImpCasts());
1257  if (!FormatString)
1258    return;
1259  if (S.FormatStringHasSArg(FormatString)) {
1260    S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
1261      << "%s" << 1 << 1;
1262    S.Diag(FDecl->getLocation(), diag::note_entity_declared_at)
1263      << FDecl->getDeclName();
1264  }
1265}
1266
1267/// Determine whether the given type has a non-null nullability annotation.
1268static bool isNonNullType(ASTContext &ctx, QualType type) {
1269  if (auto nullability = type->getNullability(ctx))
1270    return *nullability == NullabilityKind::NonNull;
1271
1272  return false;
1273}
1274
1275static void CheckNonNullArguments(Sema &S,
1276                                  const NamedDecl *FDecl,
1277                                  const FunctionProtoType *Proto,
1278                                  ArrayRef<const Expr *> Args,
1279                                  SourceLocation CallSiteLoc) {
1280  assert((FDecl || Proto) && "Need a function declaration or prototype");
1281
1282  // Check the attributes attached to the method/function itself.
1283  llvm::SmallBitVector NonNullArgs;
1284  if (FDecl) {
1285    // Handle the nonnull attribute on the function/method declaration itself.
1286    for (const auto *NonNull : FDecl->specific_attrs<NonNullAttr>()) {
1287      if (!NonNull->args_size()) {
1288        // Easy case: all pointer arguments are nonnull.
1289        for (const auto *Arg : Args)
1290          if (S.isValidPointerAttrType(Arg->getType()))
1291            CheckNonNullArgument(S, Arg, CallSiteLoc);
1292        return;
1293      }
1294
1295      for (unsigned Val : NonNull->args()) {
1296        if (Val >= Args.size())
1297          continue;
1298        if (NonNullArgs.empty())
1299          NonNullArgs.resize(Args.size());
1300        NonNullArgs.set(Val);
1301      }
1302    }
1303  }
1304
1305  if (FDecl && (isa<FunctionDecl>(FDecl) || isa<ObjCMethodDecl>(FDecl))) {
1306    // Handle the nonnull attribute on the parameters of the
1307    // function/method.
1308    ArrayRef<ParmVarDecl*> parms;
1309    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(FDecl))
1310      parms = FD->parameters();
1311    else
1312      parms = cast<ObjCMethodDecl>(FDecl)->parameters();
1313
1314    unsigned ParamIndex = 0;
1315    for (ArrayRef<ParmVarDecl*>::iterator I = parms.begin(), E = parms.end();
1316         I != E; ++I, ++ParamIndex) {
1317      const ParmVarDecl *PVD = *I;
1318      if (PVD->hasAttr<NonNullAttr>() ||
1319          isNonNullType(S.Context, PVD->getType())) {
1320        if (NonNullArgs.empty())
1321          NonNullArgs.resize(Args.size());
1322
1323        NonNullArgs.set(ParamIndex);
1324      }
1325    }
1326  } else {
1327    // If we have a non-function, non-method declaration but no
1328    // function prototype, try to dig out the function prototype.
1329    if (!Proto) {
1330      if (const ValueDecl *VD = dyn_cast<ValueDecl>(FDecl)) {
1331        QualType type = VD->getType().getNonReferenceType();
1332        if (auto pointerType = type->getAs<PointerType>())
1333          type = pointerType->getPointeeType();
1334        else if (auto blockType = type->getAs<BlockPointerType>())
1335          type = blockType->getPointeeType();
1336        // FIXME: data member pointers?
1337
1338        // Dig out the function prototype, if there is one.
1339        Proto = type->getAs<FunctionProtoType>();
1340      }
1341    }
1342
1343    // Fill in non-null argument information from the nullability
1344    // information on the parameter types (if we have them).
1345    if (Proto) {
1346      unsigned Index = 0;
1347      for (auto paramType : Proto->getParamTypes()) {
1348        if (isNonNullType(S.Context, paramType)) {
1349          if (NonNullArgs.empty())
1350            NonNullArgs.resize(Args.size());
1351
1352          NonNullArgs.set(Index);
1353        }
1354
1355        ++Index;
1356      }
1357    }
1358  }
1359
1360  // Check for non-null arguments.
1361  for (unsigned ArgIndex = 0, ArgIndexEnd = NonNullArgs.size();
1362       ArgIndex != ArgIndexEnd; ++ArgIndex) {
1363    if (NonNullArgs[ArgIndex])
1364      CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc);
1365  }
1366}
1367
1368/// Handles the checks for format strings, non-POD arguments to vararg
1369/// functions, and NULL arguments passed to non-NULL parameters.
1370void Sema::checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
1371                     ArrayRef<const Expr *> Args, bool IsMemberFunction,
1372                     SourceLocation Loc, SourceRange Range,
1373                     VariadicCallType CallType) {
1374  // FIXME: We should check as much as we can in the template definition.
1375  if (CurContext->isDependentContext())
1376    return;
1377
1378  // Printf and scanf checking.
1379  llvm::SmallBitVector CheckedVarArgs;
1380  if (FDecl) {
1381    for (const auto *I : FDecl->specific_attrs<FormatAttr>()) {
1382      // Only create vector if there are format attributes.
1383      CheckedVarArgs.resize(Args.size());
1384
1385      CheckFormatArguments(I, Args, IsMemberFunction, CallType, Loc, Range,
1386                           CheckedVarArgs);
1387    }
1388  }
1389
1390  // Refuse POD arguments that weren't caught by the format string
1391  // checks above.
1392  if (CallType != VariadicDoesNotApply) {
1393    unsigned NumParams = Proto ? Proto->getNumParams()
1394                       : FDecl && isa<FunctionDecl>(FDecl)
1395                           ? cast<FunctionDecl>(FDecl)->getNumParams()
1396                       : FDecl && isa<ObjCMethodDecl>(FDecl)
1397                           ? cast<ObjCMethodDecl>(FDecl)->param_size()
1398                       : 0;
1399
1400    for (unsigned ArgIdx = NumParams; ArgIdx < Args.size(); ++ArgIdx) {
1401      // Args[ArgIdx] can be null in malformed code.
1402      if (const Expr *Arg = Args[ArgIdx]) {
1403        if (CheckedVarArgs.empty() || !CheckedVarArgs[ArgIdx])
1404          checkVariadicArgument(Arg, CallType);
1405      }
1406    }
1407  }
1408
1409  if (FDecl || Proto) {
1410    CheckNonNullArguments(*this, FDecl, Proto, Args, Loc);
1411
1412    // Type safety checking.
1413    if (FDecl) {
1414      for (const auto *I : FDecl->specific_attrs<ArgumentWithTypeTagAttr>())
1415        CheckArgumentWithTypeTag(I, Args.data());
1416    }
1417  }
1418}
1419
1420/// CheckConstructorCall - Check a constructor call for correctness and safety
1421/// properties not enforced by the C type system.
1422void Sema::CheckConstructorCall(FunctionDecl *FDecl,
1423                                ArrayRef<const Expr *> Args,
1424                                const FunctionProtoType *Proto,
1425                                SourceLocation Loc) {
1426  VariadicCallType CallType =
1427    Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
1428  checkCall(FDecl, Proto, Args, /*IsMemberFunction=*/true, Loc, SourceRange(),
1429            CallType);
1430}
1431
1432/// CheckFunctionCall - Check a direct function call for various correctness
1433/// and safety properties not strictly enforced by the C type system.
1434bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
1435                             const FunctionProtoType *Proto) {
1436  bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) &&
1437                              isa<CXXMethodDecl>(FDecl);
1438  bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) ||
1439                          IsMemberOperatorCall;
1440  VariadicCallType CallType = getVariadicCallType(FDecl, Proto,
1441                                                  TheCall->getCallee());
1442  Expr** Args = TheCall->getArgs();
1443  unsigned NumArgs = TheCall->getNumArgs();
1444  if (IsMemberOperatorCall) {
1445    // If this is a call to a member operator, hide the first argument
1446    // from checkCall.
1447    // FIXME: Our choice of AST representation here is less than ideal.
1448    ++Args;
1449    --NumArgs;
1450  }
1451  checkCall(FDecl, Proto, llvm::makeArrayRef(Args, NumArgs),
1452            IsMemberFunction, TheCall->getRParenLoc(),
1453            TheCall->getCallee()->getSourceRange(), CallType);
1454
1455  IdentifierInfo *FnInfo = FDecl->getIdentifier();
1456  // None of the checks below are needed for functions that don't have
1457  // simple names (e.g., C++ conversion functions).
1458  if (!FnInfo)
1459    return false;
1460
1461  CheckAbsoluteValueFunction(TheCall, FDecl, FnInfo);
1462  if (getLangOpts().ObjC1)
1463    DiagnoseCStringFormatDirectiveInCFAPI(*this, FDecl, Args, NumArgs);
1464
1465  unsigned CMId = FDecl->getMemoryFunctionKind();
1466  if (CMId == 0)
1467    return false;
1468
1469  // Handle memory setting and copying functions.
1470  if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
1471    CheckStrlcpycatArguments(TheCall, FnInfo);
1472  else if (CMId == Builtin::BIstrncat)
1473    CheckStrncatArguments(TheCall, FnInfo);
1474  else
1475    CheckMemaccessArguments(TheCall, CMId, FnInfo);
1476
1477  return false;
1478}
1479
1480bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
1481                               ArrayRef<const Expr *> Args) {
1482  VariadicCallType CallType =
1483      Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply;
1484
1485  checkCall(Method, nullptr, Args,
1486            /*IsMemberFunction=*/false, lbrac, Method->getSourceRange(),
1487            CallType);
1488
1489  return false;
1490}
1491
1492bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall,
1493                            const FunctionProtoType *Proto) {
1494  QualType Ty;
1495  if (const auto *V = dyn_cast<VarDecl>(NDecl))
1496    Ty = V->getType().getNonReferenceType();
1497  else if (const auto *F = dyn_cast<FieldDecl>(NDecl))
1498    Ty = F->getType().getNonReferenceType();
1499  else
1500    return false;
1501
1502  if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType() &&
1503      !Ty->isFunctionProtoType())
1504    return false;
1505
1506  VariadicCallType CallType;
1507  if (!Proto || !Proto->isVariadic()) {
1508    CallType = VariadicDoesNotApply;
1509  } else if (Ty->isBlockPointerType()) {
1510    CallType = VariadicBlock;
1511  } else { // Ty->isFunctionPointerType()
1512    CallType = VariadicFunction;
1513  }
1514
1515  checkCall(NDecl, Proto,
1516            llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()),
1517            /*IsMemberFunction=*/false, TheCall->getRParenLoc(),
1518            TheCall->getCallee()->getSourceRange(), CallType);
1519
1520  return false;
1521}
1522
1523/// Checks function calls when a FunctionDecl or a NamedDecl is not available,
1524/// such as function pointers returned from functions.
1525bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) {
1526  VariadicCallType CallType = getVariadicCallType(/*FDecl=*/nullptr, Proto,
1527                                                  TheCall->getCallee());
1528  checkCall(/*FDecl=*/nullptr, Proto,
1529            llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()),
1530            /*IsMemberFunction=*/false, TheCall->getRParenLoc(),
1531            TheCall->getCallee()->getSourceRange(), CallType);
1532
1533  return false;
1534}
1535
1536static bool isValidOrderingForOp(int64_t Ordering, AtomicExpr::AtomicOp Op) {
1537  if (Ordering < AtomicExpr::AO_ABI_memory_order_relaxed ||
1538      Ordering > AtomicExpr::AO_ABI_memory_order_seq_cst)
1539    return false;
1540
1541  switch (Op) {
1542  case AtomicExpr::AO__c11_atomic_init:
1543    llvm_unreachable("There is no ordering argument for an init");
1544
1545  case AtomicExpr::AO__c11_atomic_load:
1546  case AtomicExpr::AO__atomic_load_n:
1547  case AtomicExpr::AO__atomic_load:
1548    return Ordering != AtomicExpr::AO_ABI_memory_order_release &&
1549           Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel;
1550
1551  case AtomicExpr::AO__c11_atomic_store:
1552  case AtomicExpr::AO__atomic_store:
1553  case AtomicExpr::AO__atomic_store_n:
1554    return Ordering != AtomicExpr::AO_ABI_memory_order_consume &&
1555           Ordering != AtomicExpr::AO_ABI_memory_order_acquire &&
1556           Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel;
1557
1558  default:
1559    return true;
1560  }
1561}
1562
1563ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
1564                                         AtomicExpr::AtomicOp Op) {
1565  CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
1566  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
1567
1568  // All these operations take one of the following forms:
1569  enum {
1570    // C    __c11_atomic_init(A *, C)
1571    Init,
1572    // C    __c11_atomic_load(A *, int)
1573    Load,
1574    // void __atomic_load(A *, CP, int)
1575    Copy,
1576    // C    __c11_atomic_add(A *, M, int)
1577    Arithmetic,
1578    // C    __atomic_exchange_n(A *, CP, int)
1579    Xchg,
1580    // void __atomic_exchange(A *, C *, CP, int)
1581    GNUXchg,
1582    // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int)
1583    C11CmpXchg,
1584    // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int)
1585    GNUCmpXchg
1586  } Form = Init;
1587  const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 };
1588  const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 };
1589  // where:
1590  //   C is an appropriate type,
1591  //   A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins,
1592  //   CP is C for __c11 builtins and GNU _n builtins and is C * otherwise,
1593  //   M is C if C is an integer, and ptrdiff_t if C is a pointer, and
1594  //   the int parameters are for orderings.
1595
1596  static_assert(AtomicExpr::AO__c11_atomic_init == 0 &&
1597                    AtomicExpr::AO__c11_atomic_fetch_xor + 1 ==
1598                        AtomicExpr::AO__atomic_load,
1599                "need to update code for modified C11 atomics");
1600  bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init &&
1601               Op <= AtomicExpr::AO__c11_atomic_fetch_xor;
1602  bool IsN = Op == AtomicExpr::AO__atomic_load_n ||
1603             Op == AtomicExpr::AO__atomic_store_n ||
1604             Op == AtomicExpr::AO__atomic_exchange_n ||
1605             Op == AtomicExpr::AO__atomic_compare_exchange_n;
1606  bool IsAddSub = false;
1607
1608  switch (Op) {
1609  case AtomicExpr::AO__c11_atomic_init:
1610    Form = Init;
1611    break;
1612
1613  case AtomicExpr::AO__c11_atomic_load:
1614  case AtomicExpr::AO__atomic_load_n:
1615    Form = Load;
1616    break;
1617
1618  case AtomicExpr::AO__c11_atomic_store:
1619  case AtomicExpr::AO__atomic_load:
1620  case AtomicExpr::AO__atomic_store:
1621  case AtomicExpr::AO__atomic_store_n:
1622    Form = Copy;
1623    break;
1624
1625  case AtomicExpr::AO__c11_atomic_fetch_add:
1626  case AtomicExpr::AO__c11_atomic_fetch_sub:
1627  case AtomicExpr::AO__atomic_fetch_add:
1628  case AtomicExpr::AO__atomic_fetch_sub:
1629  case AtomicExpr::AO__atomic_add_fetch:
1630  case AtomicExpr::AO__atomic_sub_fetch:
1631    IsAddSub = true;
1632    // Fall through.
1633  case AtomicExpr::AO__c11_atomic_fetch_and:
1634  case AtomicExpr::AO__c11_atomic_fetch_or:
1635  case AtomicExpr::AO__c11_atomic_fetch_xor:
1636  case AtomicExpr::AO__atomic_fetch_and:
1637  case AtomicExpr::AO__atomic_fetch_or:
1638  case AtomicExpr::AO__atomic_fetch_xor:
1639  case AtomicExpr::AO__atomic_fetch_nand:
1640  case AtomicExpr::AO__atomic_and_fetch:
1641  case AtomicExpr::AO__atomic_or_fetch:
1642  case AtomicExpr::AO__atomic_xor_fetch:
1643  case AtomicExpr::AO__atomic_nand_fetch:
1644    Form = Arithmetic;
1645    break;
1646
1647  case AtomicExpr::AO__c11_atomic_exchange:
1648  case AtomicExpr::AO__atomic_exchange_n:
1649    Form = Xchg;
1650    break;
1651
1652  case AtomicExpr::AO__atomic_exchange:
1653    Form = GNUXchg;
1654    break;
1655
1656  case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
1657  case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
1658    Form = C11CmpXchg;
1659    break;
1660
1661  case AtomicExpr::AO__atomic_compare_exchange:
1662  case AtomicExpr::AO__atomic_compare_exchange_n:
1663    Form = GNUCmpXchg;
1664    break;
1665  }
1666
1667  // Check we have the right number of arguments.
1668  if (TheCall->getNumArgs() < NumArgs[Form]) {
1669    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1670      << 0 << NumArgs[Form] << TheCall->getNumArgs()
1671      << TheCall->getCallee()->getSourceRange();
1672    return ExprError();
1673  } else if (TheCall->getNumArgs() > NumArgs[Form]) {
1674    Diag(TheCall->getArg(NumArgs[Form])->getLocStart(),
1675         diag::err_typecheck_call_too_many_args)
1676      << 0 << NumArgs[Form] << TheCall->getNumArgs()
1677      << TheCall->getCallee()->getSourceRange();
1678    return ExprError();
1679  }
1680
1681  // Inspect the first argument of the atomic operation.
1682  Expr *Ptr = TheCall->getArg(0);
1683  Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
1684  const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
1685  if (!pointerType) {
1686    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
1687      << Ptr->getType() << Ptr->getSourceRange();
1688    return ExprError();
1689  }
1690
1691  // For a __c11 builtin, this should be a pointer to an _Atomic type.
1692  QualType AtomTy = pointerType->getPointeeType(); // 'A'
1693  QualType ValType = AtomTy; // 'C'
1694  if (IsC11) {
1695    if (!AtomTy->isAtomicType()) {
1696      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
1697        << Ptr->getType() << Ptr->getSourceRange();
1698      return ExprError();
1699    }
1700    if (AtomTy.isConstQualified()) {
1701      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
1702        << Ptr->getType() << Ptr->getSourceRange();
1703      return ExprError();
1704    }
1705    ValType = AtomTy->getAs<AtomicType>()->getValueType();
1706  } else if (Form != Load && Op != AtomicExpr::AO__atomic_load) {
1707    if (ValType.isConstQualified()) {
1708      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_pointer)
1709        << Ptr->getType() << Ptr->getSourceRange();
1710      return ExprError();
1711    }
1712  }
1713
1714  // For an arithmetic operation, the implied arithmetic must be well-formed.
1715  if (Form == Arithmetic) {
1716    // gcc does not enforce these rules for GNU atomics, but we do so for sanity.
1717    if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) {
1718      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
1719        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
1720      return ExprError();
1721    }
1722    if (!IsAddSub && !ValType->isIntegerType()) {
1723      Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int)
1724        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
1725      return ExprError();
1726    }
1727    if (IsC11 && ValType->isPointerType() &&
1728        RequireCompleteType(Ptr->getLocStart(), ValType->getPointeeType(),
1729                            diag::err_incomplete_type)) {
1730      return ExprError();
1731    }
1732  } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) {
1733    // For __atomic_*_n operations, the value type must be a scalar integral or
1734    // pointer type which is 1, 2, 4, 8 or 16 bytes in length.
1735    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
1736      << IsC11 << Ptr->getType() << Ptr->getSourceRange();
1737    return ExprError();
1738  }
1739
1740  if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context) &&
1741      !AtomTy->isScalarType()) {
1742    // For GNU atomics, require a trivially-copyable type. This is not part of
1743    // the GNU atomics specification, but we enforce it for sanity.
1744    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy)
1745      << Ptr->getType() << Ptr->getSourceRange();
1746    return ExprError();
1747  }
1748
1749  switch (ValType.getObjCLifetime()) {
1750  case Qualifiers::OCL_None:
1751  case Qualifiers::OCL_ExplicitNone:
1752    // okay
1753    break;
1754
1755  case Qualifiers::OCL_Weak:
1756  case Qualifiers::OCL_Strong:
1757  case Qualifiers::OCL_Autoreleasing:
1758    // FIXME: Can this happen? By this point, ValType should be known
1759    // to be trivially copyable.
1760    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
1761      << ValType << Ptr->getSourceRange();
1762    return ExprError();
1763  }
1764
1765  // atomic_fetch_or takes a pointer to a volatile 'A'.  We shouldn't let the
1766  // volatile-ness of the pointee-type inject itself into the result or the
1767  // other operands.
1768  ValType.removeLocalVolatile();
1769  QualType ResultType = ValType;
1770  if (Form == Copy || Form == GNUXchg || Form == Init)
1771    ResultType = Context.VoidTy;
1772  else if (Form == C11CmpXchg || Form == GNUCmpXchg)
1773    ResultType = Context.BoolTy;
1774
1775  // The type of a parameter passed 'by value'. In the GNU atomics, such
1776  // arguments are actually passed as pointers.
1777  QualType ByValType = ValType; // 'CP'
1778  if (!IsC11 && !IsN)
1779    ByValType = Ptr->getType();
1780
1781  // FIXME: __atomic_load allows the first argument to be a a pointer to const
1782  // but not the second argument. We need to manually remove possible const
1783  // qualifiers.
1784
1785  // The first argument --- the pointer --- has a fixed type; we
1786  // deduce the types of the rest of the arguments accordingly.  Walk
1787  // the remaining arguments, converting them to the deduced value type.
1788  for (unsigned i = 1; i != NumArgs[Form]; ++i) {
1789    QualType Ty;
1790    if (i < NumVals[Form] + 1) {
1791      switch (i) {
1792      case 1:
1793        // The second argument is the non-atomic operand. For arithmetic, this
1794        // is always passed by value, and for a compare_exchange it is always
1795        // passed by address. For the rest, GNU uses by-address and C11 uses
1796        // by-value.
1797        assert(Form != Load);
1798        if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
1799          Ty = ValType;
1800        else if (Form == Copy || Form == Xchg)
1801          Ty = ByValType;
1802        else if (Form == Arithmetic)
1803          Ty = Context.getPointerDiffType();
1804        else {
1805          Expr *ValArg = TheCall->getArg(i);
1806          unsigned AS = 0;
1807          // Keep address space of non-atomic pointer type.
1808          if (const PointerType *PtrTy =
1809                  ValArg->getType()->getAs<PointerType>()) {
1810            AS = PtrTy->getPointeeType().getAddressSpace();
1811          }
1812          Ty = Context.getPointerType(
1813              Context.getAddrSpaceQualType(ValType.getUnqualifiedType(), AS));
1814        }
1815        break;
1816      case 2:
1817        // The third argument to compare_exchange / GNU exchange is a
1818        // (pointer to a) desired value.
1819        Ty = ByValType;
1820        break;
1821      case 3:
1822        // The fourth argument to GNU compare_exchange is a 'weak' flag.
1823        Ty = Context.BoolTy;
1824        break;
1825      }
1826    } else {
1827      // The order(s) are always converted to int.
1828      Ty = Context.IntTy;
1829    }
1830
1831    InitializedEntity Entity =
1832        InitializedEntity::InitializeParameter(Context, Ty, false);
1833    ExprResult Arg = TheCall->getArg(i);
1834    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
1835    if (Arg.isInvalid())
1836      return true;
1837    TheCall->setArg(i, Arg.get());
1838  }
1839
1840  // Permute the arguments into a 'consistent' order.
1841  SmallVector<Expr*, 5> SubExprs;
1842  SubExprs.push_back(Ptr);
1843  switch (Form) {
1844  case Init:
1845    // Note, AtomicExpr::getVal1() has a special case for this atomic.
1846    SubExprs.push_back(TheCall->getArg(1)); // Val1
1847    break;
1848  case Load:
1849    SubExprs.push_back(TheCall->getArg(1)); // Order
1850    break;
1851  case Copy:
1852  case Arithmetic:
1853  case Xchg:
1854    SubExprs.push_back(TheCall->getArg(2)); // Order
1855    SubExprs.push_back(TheCall->getArg(1)); // Val1
1856    break;
1857  case GNUXchg:
1858    // Note, AtomicExpr::getVal2() has a special case for this atomic.
1859    SubExprs.push_back(TheCall->getArg(3)); // Order
1860    SubExprs.push_back(TheCall->getArg(1)); // Val1
1861    SubExprs.push_back(TheCall->getArg(2)); // Val2
1862    break;
1863  case C11CmpXchg:
1864    SubExprs.push_back(TheCall->getArg(3)); // Order
1865    SubExprs.push_back(TheCall->getArg(1)); // Val1
1866    SubExprs.push_back(TheCall->getArg(4)); // OrderFail
1867    SubExprs.push_back(TheCall->getArg(2)); // Val2
1868    break;
1869  case GNUCmpXchg:
1870    SubExprs.push_back(TheCall->getArg(4)); // Order
1871    SubExprs.push_back(TheCall->getArg(1)); // Val1
1872    SubExprs.push_back(TheCall->getArg(5)); // OrderFail
1873    SubExprs.push_back(TheCall->getArg(2)); // Val2
1874    SubExprs.push_back(TheCall->getArg(3)); // Weak
1875    break;
1876  }
1877
1878  if (SubExprs.size() >= 2 && Form != Init) {
1879    llvm::APSInt Result(32);
1880    if (SubExprs[1]->isIntegerConstantExpr(Result, Context) &&
1881        !isValidOrderingForOp(Result.getSExtValue(), Op))
1882      Diag(SubExprs[1]->getLocStart(),
1883           diag::warn_atomic_op_has_invalid_memory_order)
1884          << SubExprs[1]->getSourceRange();
1885  }
1886
1887  AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
1888                                            SubExprs, ResultType, Op,
1889                                            TheCall->getRParenLoc());
1890
1891  if ((Op == AtomicExpr::AO__c11_atomic_load ||
1892       (Op == AtomicExpr::AO__c11_atomic_store)) &&
1893      Context.AtomicUsesUnsupportedLibcall(AE))
1894    Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) <<
1895    ((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1);
1896
1897  return AE;
1898}
1899
1900
1901/// checkBuiltinArgument - Given a call to a builtin function, perform
1902/// normal type-checking on the given argument, updating the call in
1903/// place.  This is useful when a builtin function requires custom
1904/// type-checking for some of its arguments but not necessarily all of
1905/// them.
1906///
1907/// Returns true on error.
1908static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
1909  FunctionDecl *Fn = E->getDirectCallee();
1910  assert(Fn && "builtin call without direct callee!");
1911
1912  ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
1913  InitializedEntity Entity =
1914    InitializedEntity::InitializeParameter(S.Context, Param);
1915
1916  ExprResult Arg = E->getArg(0);
1917  Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
1918  if (Arg.isInvalid())
1919    return true;
1920
1921  E->setArg(ArgIndex, Arg.get());
1922  return false;
1923}
1924
1925/// SemaBuiltinAtomicOverloaded - We have a call to a function like
1926/// __sync_fetch_and_add, which is an overloaded function based on the pointer
1927/// type of its first argument.  The main ActOnCallExpr routines have already
1928/// promoted the types of arguments because all of these calls are prototyped as
1929/// void(...).
1930///
1931/// This function goes through and does final semantic checking for these
1932/// builtins,
1933ExprResult
1934Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
1935  CallExpr *TheCall = (CallExpr *)TheCallResult.get();
1936  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
1937  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
1938
1939  // Ensure that we have at least one argument to do type inference from.
1940  if (TheCall->getNumArgs() < 1) {
1941    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
1942      << 0 << 1 << TheCall->getNumArgs()
1943      << TheCall->getCallee()->getSourceRange();
1944    return ExprError();
1945  }
1946
1947  // Inspect the first argument of the atomic builtin.  This should always be
1948  // a pointer type, whose element is an integral scalar or pointer type.
1949  // Because it is a pointer type, we don't have to worry about any implicit
1950  // casts here.
1951  // FIXME: We don't allow floating point scalars as input.
1952  Expr *FirstArg = TheCall->getArg(0);
1953  ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
1954  if (FirstArgResult.isInvalid())
1955    return ExprError();
1956  FirstArg = FirstArgResult.get();
1957  TheCall->setArg(0, FirstArg);
1958
1959  const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
1960  if (!pointerType) {
1961    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
1962      << FirstArg->getType() << FirstArg->getSourceRange();
1963    return ExprError();
1964  }
1965
1966  QualType ValType = pointerType->getPointeeType();
1967  if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
1968      !ValType->isBlockPointerType()) {
1969    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
1970      << FirstArg->getType() << FirstArg->getSourceRange();
1971    return ExprError();
1972  }
1973
1974  switch (ValType.getObjCLifetime()) {
1975  case Qualifiers::OCL_None:
1976  case Qualifiers::OCL_ExplicitNone:
1977    // okay
1978    break;
1979
1980  case Qualifiers::OCL_Weak:
1981  case Qualifiers::OCL_Strong:
1982  case Qualifiers::OCL_Autoreleasing:
1983    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
1984      << ValType << FirstArg->getSourceRange();
1985    return ExprError();
1986  }
1987
1988  // Strip any qualifiers off ValType.
1989  ValType = ValType.getUnqualifiedType();
1990
1991  // The majority of builtins return a value, but a few have special return
1992  // types, so allow them to override appropriately below.
1993  QualType ResultType = ValType;
1994
1995  // We need to figure out which concrete builtin this maps onto.  For example,
1996  // __sync_fetch_and_add with a 2 byte object turns into
1997  // __sync_fetch_and_add_2.
1998#define BUILTIN_ROW(x) \
1999  { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
2000    Builtin::BI##x##_8, Builtin::BI##x##_16 }
2001
2002  static const unsigned BuiltinIndices[][5] = {
2003    BUILTIN_ROW(__sync_fetch_and_add),
2004    BUILTIN_ROW(__sync_fetch_and_sub),
2005    BUILTIN_ROW(__sync_fetch_and_or),
2006    BUILTIN_ROW(__sync_fetch_and_and),
2007    BUILTIN_ROW(__sync_fetch_and_xor),
2008    BUILTIN_ROW(__sync_fetch_and_nand),
2009
2010    BUILTIN_ROW(__sync_add_and_fetch),
2011    BUILTIN_ROW(__sync_sub_and_fetch),
2012    BUILTIN_ROW(__sync_and_and_fetch),
2013    BUILTIN_ROW(__sync_or_and_fetch),
2014    BUILTIN_ROW(__sync_xor_and_fetch),
2015    BUILTIN_ROW(__sync_nand_and_fetch),
2016
2017    BUILTIN_ROW(__sync_val_compare_and_swap),
2018    BUILTIN_ROW(__sync_bool_compare_and_swap),
2019    BUILTIN_ROW(__sync_lock_test_and_set),
2020    BUILTIN_ROW(__sync_lock_release),
2021    BUILTIN_ROW(__sync_swap)
2022  };
2023#undef BUILTIN_ROW
2024
2025  // Determine the index of the size.
2026  unsigned SizeIndex;
2027  switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
2028  case 1: SizeIndex = 0; break;
2029  case 2: SizeIndex = 1; break;
2030  case 4: SizeIndex = 2; break;
2031  case 8: SizeIndex = 3; break;
2032  case 16: SizeIndex = 4; break;
2033  default:
2034    Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
2035      << FirstArg->getType() << FirstArg->getSourceRange();
2036    return ExprError();
2037  }
2038
2039  // Each of these builtins has one pointer argument, followed by some number of
2040  // values (0, 1 or 2) followed by a potentially empty varags list of stuff
2041  // that we ignore.  Find out which row of BuiltinIndices to read from as well
2042  // as the number of fixed args.
2043  unsigned BuiltinID = FDecl->getBuiltinID();
2044  unsigned BuiltinIndex, NumFixed = 1;
2045  bool WarnAboutSemanticsChange = false;
2046  switch (BuiltinID) {
2047  default: llvm_unreachable("Unknown overloaded atomic builtin!");
2048  case Builtin::BI__sync_fetch_and_add:
2049  case Builtin::BI__sync_fetch_and_add_1:
2050  case Builtin::BI__sync_fetch_and_add_2:
2051  case Builtin::BI__sync_fetch_and_add_4:
2052  case Builtin::BI__sync_fetch_and_add_8:
2053  case Builtin::BI__sync_fetch_and_add_16:
2054    BuiltinIndex = 0;
2055    break;
2056
2057  case Builtin::BI__sync_fetch_and_sub:
2058  case Builtin::BI__sync_fetch_and_sub_1:
2059  case Builtin::BI__sync_fetch_and_sub_2:
2060  case Builtin::BI__sync_fetch_and_sub_4:
2061  case Builtin::BI__sync_fetch_and_sub_8:
2062  case Builtin::BI__sync_fetch_and_sub_16:
2063    BuiltinIndex = 1;
2064    break;
2065
2066  case Builtin::BI__sync_fetch_and_or:
2067  case Builtin::BI__sync_fetch_and_or_1:
2068  case Builtin::BI__sync_fetch_and_or_2:
2069  case Builtin::BI__sync_fetch_and_or_4:
2070  case Builtin::BI__sync_fetch_and_or_8:
2071  case Builtin::BI__sync_fetch_and_or_16:
2072    BuiltinIndex = 2;
2073    break;
2074
2075  case Builtin::BI__sync_fetch_and_and:
2076  case Builtin::BI__sync_fetch_and_and_1:
2077  case Builtin::BI__sync_fetch_and_and_2:
2078  case Builtin::BI__sync_fetch_and_and_4:
2079  case Builtin::BI__sync_fetch_and_and_8:
2080  case Builtin::BI__sync_fetch_and_and_16:
2081    BuiltinIndex = 3;
2082    break;
2083
2084  case Builtin::BI__sync_fetch_and_xor:
2085  case Builtin::BI__sync_fetch_and_xor_1:
2086  case Builtin::BI__sync_fetch_and_xor_2:
2087  case Builtin::BI__sync_fetch_and_xor_4:
2088  case Builtin::BI__sync_fetch_and_xor_8:
2089  case Builtin::BI__sync_fetch_and_xor_16:
2090    BuiltinIndex = 4;
2091    break;
2092
2093  case Builtin::BI__sync_fetch_and_nand:
2094  case Builtin::BI__sync_fetch_and_nand_1:
2095  case Builtin::BI__sync_fetch_and_nand_2:
2096  case Builtin::BI__sync_fetch_and_nand_4:
2097  case Builtin::BI__sync_fetch_and_nand_8:
2098  case Builtin::BI__sync_fetch_and_nand_16:
2099    BuiltinIndex = 5;
2100    WarnAboutSemanticsChange = true;
2101    break;
2102
2103  case Builtin::BI__sync_add_and_fetch:
2104  case Builtin::BI__sync_add_and_fetch_1:
2105  case Builtin::BI__sync_add_and_fetch_2:
2106  case Builtin::BI__sync_add_and_fetch_4:
2107  case Builtin::BI__sync_add_and_fetch_8:
2108  case Builtin::BI__sync_add_and_fetch_16:
2109    BuiltinIndex = 6;
2110    break;
2111
2112  case Builtin::BI__sync_sub_and_fetch:
2113  case Builtin::BI__sync_sub_and_fetch_1:
2114  case Builtin::BI__sync_sub_and_fetch_2:
2115  case Builtin::BI__sync_sub_and_fetch_4:
2116  case Builtin::BI__sync_sub_and_fetch_8:
2117  case Builtin::BI__sync_sub_and_fetch_16:
2118    BuiltinIndex = 7;
2119    break;
2120
2121  case Builtin::BI__sync_and_and_fetch:
2122  case Builtin::BI__sync_and_and_fetch_1:
2123  case Builtin::BI__sync_and_and_fetch_2:
2124  case Builtin::BI__sync_and_and_fetch_4:
2125  case Builtin::BI__sync_and_and_fetch_8:
2126  case Builtin::BI__sync_and_and_fetch_16:
2127    BuiltinIndex = 8;
2128    break;
2129
2130  case Builtin::BI__sync_or_and_fetch:
2131  case Builtin::BI__sync_or_and_fetch_1:
2132  case Builtin::BI__sync_or_and_fetch_2:
2133  case Builtin::BI__sync_or_and_fetch_4:
2134  case Builtin::BI__sync_or_and_fetch_8:
2135  case Builtin::BI__sync_or_and_fetch_16:
2136    BuiltinIndex = 9;
2137    break;
2138
2139  case Builtin::BI__sync_xor_and_fetch:
2140  case Builtin::BI__sync_xor_and_fetch_1:
2141  case Builtin::BI__sync_xor_and_fetch_2:
2142  case Builtin::BI__sync_xor_and_fetch_4:
2143  case Builtin::BI__sync_xor_and_fetch_8:
2144  case Builtin::BI__sync_xor_and_fetch_16:
2145    BuiltinIndex = 10;
2146    break;
2147
2148  case Builtin::BI__sync_nand_and_fetch:
2149  case Builtin::BI__sync_nand_and_fetch_1:
2150  case Builtin::BI__sync_nand_and_fetch_2:
2151  case Builtin::BI__sync_nand_and_fetch_4:
2152  case Builtin::BI__sync_nand_and_fetch_8:
2153  case Builtin::BI__sync_nand_and_fetch_16:
2154    BuiltinIndex = 11;
2155    WarnAboutSemanticsChange = true;
2156    break;
2157
2158  case Builtin::BI__sync_val_compare_and_swap:
2159  case Builtin::BI__sync_val_compare_and_swap_1:
2160  case Builtin::BI__sync_val_compare_and_swap_2:
2161  case Builtin::BI__sync_val_compare_and_swap_4:
2162  case Builtin::BI__sync_val_compare_and_swap_8:
2163  case Builtin::BI__sync_val_compare_and_swap_16:
2164    BuiltinIndex = 12;
2165    NumFixed = 2;
2166    break;
2167
2168  case Builtin::BI__sync_bool_compare_and_swap:
2169  case Builtin::BI__sync_bool_compare_and_swap_1:
2170  case Builtin::BI__sync_bool_compare_and_swap_2:
2171  case Builtin::BI__sync_bool_compare_and_swap_4:
2172  case Builtin::BI__sync_bool_compare_and_swap_8:
2173  case Builtin::BI__sync_bool_compare_and_swap_16:
2174    BuiltinIndex = 13;
2175    NumFixed = 2;
2176    ResultType = Context.BoolTy;
2177    break;
2178
2179  case Builtin::BI__sync_lock_test_and_set:
2180  case Builtin::BI__sync_lock_test_and_set_1:
2181  case Builtin::BI__sync_lock_test_and_set_2:
2182  case Builtin::BI__sync_lock_test_and_set_4:
2183  case Builtin::BI__sync_lock_test_and_set_8:
2184  case Builtin::BI__sync_lock_test_and_set_16:
2185    BuiltinIndex = 14;
2186    break;
2187
2188  case Builtin::BI__sync_lock_release:
2189  case Builtin::BI__sync_lock_release_1:
2190  case Builtin::BI__sync_lock_release_2:
2191  case Builtin::BI__sync_lock_release_4:
2192  case Builtin::BI__sync_lock_release_8:
2193  case Builtin::BI__sync_lock_release_16:
2194    BuiltinIndex = 15;
2195    NumFixed = 0;
2196    ResultType = Context.VoidTy;
2197    break;
2198
2199  case Builtin::BI__sync_swap:
2200  case Builtin::BI__sync_swap_1:
2201  case Builtin::BI__sync_swap_2:
2202  case Builtin::BI__sync_swap_4:
2203  case Builtin::BI__sync_swap_8:
2204  case Builtin::BI__sync_swap_16:
2205    BuiltinIndex = 16;
2206    break;
2207  }
2208
2209  // Now that we know how many fixed arguments we expect, first check that we
2210  // have at least that many.
2211  if (TheCall->getNumArgs() < 1+NumFixed) {
2212    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
2213      << 0 << 1+NumFixed << TheCall->getNumArgs()
2214      << TheCall->getCallee()->getSourceRange();
2215    return ExprError();
2216  }
2217
2218  if (WarnAboutSemanticsChange) {
2219    Diag(TheCall->getLocEnd(), diag::warn_sync_fetch_and_nand_semantics_change)
2220      << TheCall->getCallee()->getSourceRange();
2221  }
2222
2223  // Get the decl for the concrete builtin from this, we can tell what the
2224  // concrete integer type we should convert to is.
2225  unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
2226  const char *NewBuiltinName = Context.BuiltinInfo.getName(NewBuiltinID);
2227  FunctionDecl *NewBuiltinDecl;
2228  if (NewBuiltinID == BuiltinID)
2229    NewBuiltinDecl = FDecl;
2230  else {
2231    // Perform builtin lookup to avoid redeclaring it.
2232    DeclarationName DN(&Context.Idents.get(NewBuiltinName));
2233    LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName);
2234    LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true);
2235    assert(Res.getFoundDecl());
2236    NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl());
2237    if (!NewBuiltinDecl)
2238      return ExprError();
2239  }
2240
2241  // The first argument --- the pointer --- has a fixed type; we
2242  // deduce the types of the rest of the arguments accordingly.  Walk
2243  // the remaining arguments, converting them to the deduced value type.
2244  for (unsigned i = 0; i != NumFixed; ++i) {
2245    ExprResult Arg = TheCall->getArg(i+1);
2246
2247    // GCC does an implicit conversion to the pointer or integer ValType.  This
2248    // can fail in some cases (1i -> int**), check for this error case now.
2249    // Initialize the argument.
2250    InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
2251                                                   ValType, /*consume*/ false);
2252    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
2253    if (Arg.isInvalid())
2254      return ExprError();
2255
2256    // Okay, we have something that *can* be converted to the right type.  Check
2257    // to see if there is a potentially weird extension going on here.  This can
2258    // happen when you do an atomic operation on something like an char* and
2259    // pass in 42.  The 42 gets converted to char.  This is even more strange
2260    // for things like 45.123 -> char, etc.
2261    // FIXME: Do this check.
2262    TheCall->setArg(i+1, Arg.get());
2263  }
2264
2265  ASTContext& Context = this->getASTContext();
2266
2267  // Create a new DeclRefExpr to refer to the new decl.
2268  DeclRefExpr* NewDRE = DeclRefExpr::Create(
2269      Context,
2270      DRE->getQualifierLoc(),
2271      SourceLocation(),
2272      NewBuiltinDecl,
2273      /*enclosing*/ false,
2274      DRE->getLocation(),
2275      Context.BuiltinFnTy,
2276      DRE->getValueKind());
2277
2278  // Set the callee in the CallExpr.
2279  // FIXME: This loses syntactic information.
2280  QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType());
2281  ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy,
2282                                              CK_BuiltinFnToFnPtr);
2283  TheCall->setCallee(PromotedCall.get());
2284
2285  // Change the result type of the call to match the original value type. This
2286  // is arbitrary, but the codegen for these builtins ins design to handle it
2287  // gracefully.
2288  TheCall->setType(ResultType);
2289
2290  return TheCallResult;
2291}
2292
2293/// SemaBuiltinNontemporalOverloaded - We have a call to
2294/// __builtin_nontemporal_store or __builtin_nontemporal_load, which is an
2295/// overloaded function based on the pointer type of its last argument.
2296///
2297/// This function goes through and does final semantic checking for these
2298/// builtins.
2299ExprResult Sema::SemaBuiltinNontemporalOverloaded(ExprResult TheCallResult) {
2300  CallExpr *TheCall = (CallExpr *)TheCallResult.get();
2301  DeclRefExpr *DRE =
2302      cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
2303  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
2304  unsigned BuiltinID = FDecl->getBuiltinID();
2305  assert((BuiltinID == Builtin::BI__builtin_nontemporal_store ||
2306          BuiltinID == Builtin::BI__builtin_nontemporal_load) &&
2307         "Unexpected nontemporal load/store builtin!");
2308  bool isStore = BuiltinID == Builtin::BI__builtin_nontemporal_store;
2309  unsigned numArgs = isStore ? 2 : 1;
2310
2311  // Ensure that we have the proper number of arguments.
2312  if (checkArgCount(*this, TheCall, numArgs))
2313    return ExprError();
2314
2315  // Inspect the last argument of the nontemporal builtin.  This should always
2316  // be a pointer type, from which we imply the type of the memory access.
2317  // Because it is a pointer type, we don't have to worry about any implicit
2318  // casts here.
2319  Expr *PointerArg = TheCall->getArg(numArgs - 1);
2320  ExprResult PointerArgResult =
2321      DefaultFunctionArrayLvalueConversion(PointerArg);
2322
2323  if (PointerArgResult.isInvalid())
2324    return ExprError();
2325  PointerArg = PointerArgResult.get();
2326  TheCall->setArg(numArgs - 1, PointerArg);
2327
2328  const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>();
2329  if (!pointerType) {
2330    Diag(DRE->getLocStart(), diag::err_nontemporal_builtin_must_be_pointer)
2331        << PointerArg->getType() << PointerArg->getSourceRange();
2332    return ExprError();
2333  }
2334
2335  QualType ValType = pointerType->getPointeeType();
2336
2337  // Strip any qualifiers off ValType.
2338  ValType = ValType.getUnqualifiedType();
2339  if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
2340      !ValType->isBlockPointerType() && !ValType->isFloatingType() &&
2341      !ValType->isVectorType()) {
2342    Diag(DRE->getLocStart(),
2343         diag::err_nontemporal_builtin_must_be_pointer_intfltptr_or_vector)
2344        << PointerArg->getType() << PointerArg->getSourceRange();
2345    return ExprError();
2346  }
2347
2348  if (!isStore) {
2349    TheCall->setType(ValType);
2350    return TheCallResult;
2351  }
2352
2353  ExprResult ValArg = TheCall->getArg(0);
2354  InitializedEntity Entity = InitializedEntity::InitializeParameter(
2355      Context, ValType, /*consume*/ false);
2356  ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg);
2357  if (ValArg.isInvalid())
2358    return ExprError();
2359
2360  TheCall->setArg(0, ValArg.get());
2361  TheCall->setType(Context.VoidTy);
2362  return TheCallResult;
2363}
2364
2365/// CheckObjCString - Checks that the argument to the builtin
2366/// CFString constructor is correct
2367/// Note: It might also make sense to do the UTF-16 conversion here (would
2368/// simplify the backend).
2369bool Sema::CheckObjCString(Expr *Arg) {
2370  Arg = Arg->IgnoreParenCasts();
2371  StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
2372
2373  if (!Literal || !Literal->isAscii()) {
2374    Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
2375      << Arg->getSourceRange();
2376    return true;
2377  }
2378
2379  if (Literal->containsNonAsciiOrNull()) {
2380    StringRef String = Literal->getString();
2381    unsigned NumBytes = String.size();
2382    SmallVector<UTF16, 128> ToBuf(NumBytes);
2383    const UTF8 *FromPtr = (const UTF8 *)String.data();
2384    UTF16 *ToPtr = &ToBuf[0];
2385
2386    ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
2387                                                 &ToPtr, ToPtr + NumBytes,
2388                                                 strictConversion);
2389    // Check for conversion failure.
2390    if (Result != conversionOK)
2391      Diag(Arg->getLocStart(),
2392           diag::warn_cfstring_truncated) << Arg->getSourceRange();
2393  }
2394  return false;
2395}
2396
2397/// Check the arguments to '__builtin_va_start' or '__builtin_ms_va_start'
2398/// for validity.  Emit an error and return true on failure; return false
2399/// on success.
2400bool Sema::SemaBuiltinVAStartImpl(CallExpr *TheCall) {
2401  Expr *Fn = TheCall->getCallee();
2402  if (TheCall->getNumArgs() > 2) {
2403    Diag(TheCall->getArg(2)->getLocStart(),
2404         diag::err_typecheck_call_too_many_args)
2405      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
2406      << Fn->getSourceRange()
2407      << SourceRange(TheCall->getArg(2)->getLocStart(),
2408                     (*(TheCall->arg_end()-1))->getLocEnd());
2409    return true;
2410  }
2411
2412  if (TheCall->getNumArgs() < 2) {
2413    return Diag(TheCall->getLocEnd(),
2414      diag::err_typecheck_call_too_few_args_at_least)
2415      << 0 /*function call*/ << 2 << TheCall->getNumArgs();
2416  }
2417
2418  // Type-check the first argument normally.
2419  if (checkBuiltinArgument(*this, TheCall, 0))
2420    return true;
2421
2422  // Determine whether the current function is variadic or not.
2423  BlockScopeInfo *CurBlock = getCurBlock();
2424  bool isVariadic;
2425  if (CurBlock)
2426    isVariadic = CurBlock->TheDecl->isVariadic();
2427  else if (FunctionDecl *FD = getCurFunctionDecl())
2428    isVariadic = FD->isVariadic();
2429  else
2430    isVariadic = getCurMethodDecl()->isVariadic();
2431
2432  if (!isVariadic) {
2433    Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
2434    return true;
2435  }
2436
2437  // Verify that the second argument to the builtin is the last argument of the
2438  // current function or method.
2439  bool SecondArgIsLastNamedArgument = false;
2440  const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
2441
2442  // These are valid if SecondArgIsLastNamedArgument is false after the next
2443  // block.
2444  QualType Type;
2445  SourceLocation ParamLoc;
2446
2447  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
2448    if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
2449      // FIXME: This isn't correct for methods (results in bogus warning).
2450      // Get the last formal in the current function.
2451      const ParmVarDecl *LastArg;
2452      if (CurBlock)
2453        LastArg = *(CurBlock->TheDecl->param_end()-1);
2454      else if (FunctionDecl *FD = getCurFunctionDecl())
2455        LastArg = *(FD->param_end()-1);
2456      else
2457        LastArg = *(getCurMethodDecl()->param_end()-1);
2458      SecondArgIsLastNamedArgument = PV == LastArg;
2459
2460      Type = PV->getType();
2461      ParamLoc = PV->getLocation();
2462    }
2463  }
2464
2465  if (!SecondArgIsLastNamedArgument)
2466    Diag(TheCall->getArg(1)->getLocStart(),
2467         diag::warn_second_parameter_of_va_start_not_last_named_argument);
2468  else if (Type->isReferenceType()) {
2469    Diag(Arg->getLocStart(),
2470         diag::warn_va_start_of_reference_type_is_undefined);
2471    Diag(ParamLoc, diag::note_parameter_type) << Type;
2472  }
2473
2474  TheCall->setType(Context.VoidTy);
2475  return false;
2476}
2477
2478/// Check the arguments to '__builtin_va_start' for validity, and that
2479/// it was called from a function of the native ABI.
2480/// Emit an error and return true on failure; return false on success.
2481bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
2482  // On x86-64 Unix, don't allow this in Win64 ABI functions.
2483  // On x64 Windows, don't allow this in System V ABI functions.
2484  // (Yes, that means there's no corresponding way to support variadic
2485  // System V ABI functions on Windows.)
2486  if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86_64) {
2487    unsigned OS = Context.getTargetInfo().getTriple().getOS();
2488    clang::CallingConv CC = CC_C;
2489    if (const FunctionDecl *FD = getCurFunctionDecl())
2490      CC = FD->getType()->getAs<FunctionType>()->getCallConv();
2491    if ((OS == llvm::Triple::Win32 && CC == CC_X86_64SysV) ||
2492        (OS != llvm::Triple::Win32 && CC == CC_X86_64Win64))
2493      return Diag(TheCall->getCallee()->getLocStart(),
2494                  diag::err_va_start_used_in_wrong_abi_function)
2495             << (OS != llvm::Triple::Win32);
2496  }
2497  return SemaBuiltinVAStartImpl(TheCall);
2498}
2499
2500/// Check the arguments to '__builtin_ms_va_start' for validity, and that
2501/// it was called from a Win64 ABI function.
2502/// Emit an error and return true on failure; return false on success.
2503bool Sema::SemaBuiltinMSVAStart(CallExpr *TheCall) {
2504  // This only makes sense for x86-64.
2505  const llvm::Triple &TT = Context.getTargetInfo().getTriple();
2506  Expr *Callee = TheCall->getCallee();
2507  if (TT.getArch() != llvm::Triple::x86_64)
2508    return Diag(Callee->getLocStart(), diag::err_x86_builtin_32_bit_tgt);
2509  // Don't allow this in System V ABI functions.
2510  clang::CallingConv CC = CC_C;
2511  if (const FunctionDecl *FD = getCurFunctionDecl())
2512    CC = FD->getType()->getAs<FunctionType>()->getCallConv();
2513  if (CC == CC_X86_64SysV ||
2514      (TT.getOS() != llvm::Triple::Win32 && CC != CC_X86_64Win64))
2515    return Diag(Callee->getLocStart(),
2516                diag::err_ms_va_start_used_in_sysv_function);
2517  return SemaBuiltinVAStartImpl(TheCall);
2518}
2519
2520bool Sema::SemaBuiltinVAStartARM(CallExpr *Call) {
2521  // void __va_start(va_list *ap, const char *named_addr, size_t slot_size,
2522  //                 const char *named_addr);
2523
2524  Expr *Func = Call->getCallee();
2525
2526  if (Call->getNumArgs() < 3)
2527    return Diag(Call->getLocEnd(),
2528                diag::err_typecheck_call_too_few_args_at_least)
2529           << 0 /*function call*/ << 3 << Call->getNumArgs();
2530
2531  // Determine whether the current function is variadic or not.
2532  bool IsVariadic;
2533  if (BlockScopeInfo *CurBlock = getCurBlock())
2534    IsVariadic = CurBlock->TheDecl->isVariadic();
2535  else if (FunctionDecl *FD = getCurFunctionDecl())
2536    IsVariadic = FD->isVariadic();
2537  else if (ObjCMethodDecl *MD = getCurMethodDecl())
2538    IsVariadic = MD->isVariadic();
2539  else
2540    llvm_unreachable("unexpected statement type");
2541
2542  if (!IsVariadic) {
2543    Diag(Func->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
2544    return true;
2545  }
2546
2547  // Type-check the first argument normally.
2548  if (checkBuiltinArgument(*this, Call, 0))
2549    return true;
2550
2551  const struct {
2552    unsigned ArgNo;
2553    QualType Type;
2554  } ArgumentTypes[] = {
2555    { 1, Context.getPointerType(Context.CharTy.withConst()) },
2556    { 2, Context.getSizeType() },
2557  };
2558
2559  for (const auto &AT : ArgumentTypes) {
2560    const Expr *Arg = Call->getArg(AT.ArgNo)->IgnoreParens();
2561    if (Arg->getType().getCanonicalType() == AT.Type.getCanonicalType())
2562      continue;
2563    Diag(Arg->getLocStart(), diag::err_typecheck_convert_incompatible)
2564      << Arg->getType() << AT.Type << 1 /* different class */
2565      << 0 /* qualifier difference */ << 3 /* parameter mismatch */
2566      << AT.ArgNo + 1 << Arg->getType() << AT.Type;
2567  }
2568
2569  return false;
2570}
2571
2572/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
2573/// friends.  This is declared to take (...), so we have to check everything.
2574bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
2575  if (TheCall->getNumArgs() < 2)
2576    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
2577      << 0 << 2 << TheCall->getNumArgs()/*function call*/;
2578  if (TheCall->getNumArgs() > 2)
2579    return Diag(TheCall->getArg(2)->getLocStart(),
2580                diag::err_typecheck_call_too_many_args)
2581      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
2582      << SourceRange(TheCall->getArg(2)->getLocStart(),
2583                     (*(TheCall->arg_end()-1))->getLocEnd());
2584
2585  ExprResult OrigArg0 = TheCall->getArg(0);
2586  ExprResult OrigArg1 = TheCall->getArg(1);
2587
2588  // Do standard promotions between the two arguments, returning their common
2589  // type.
2590  QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
2591  if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
2592    return true;
2593
2594  // Make sure any conversions are pushed back into the call; this is
2595  // type safe since unordered compare builtins are declared as "_Bool
2596  // foo(...)".
2597  TheCall->setArg(0, OrigArg0.get());
2598  TheCall->setArg(1, OrigArg1.get());
2599
2600  if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
2601    return false;
2602
2603  // If the common type isn't a real floating type, then the arguments were
2604  // invalid for this operation.
2605  if (Res.isNull() || !Res->isRealFloatingType())
2606    return Diag(OrigArg0.get()->getLocStart(),
2607                diag::err_typecheck_call_invalid_ordered_compare)
2608      << OrigArg0.get()->getType() << OrigArg1.get()->getType()
2609      << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
2610
2611  return false;
2612}
2613
2614/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
2615/// __builtin_isnan and friends.  This is declared to take (...), so we have
2616/// to check everything. We expect the last argument to be a floating point
2617/// value.
2618bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
2619  if (TheCall->getNumArgs() < NumArgs)
2620    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
2621      << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
2622  if (TheCall->getNumArgs() > NumArgs)
2623    return Diag(TheCall->getArg(NumArgs)->getLocStart(),
2624                diag::err_typecheck_call_too_many_args)
2625      << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
2626      << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
2627                     (*(TheCall->arg_end()-1))->getLocEnd());
2628
2629  Expr *OrigArg = TheCall->getArg(NumArgs-1);
2630
2631  if (OrigArg->isTypeDependent())
2632    return false;
2633
2634  // This operation requires a non-_Complex floating-point number.
2635  if (!OrigArg->getType()->isRealFloatingType())
2636    return Diag(OrigArg->getLocStart(),
2637                diag::err_typecheck_call_invalid_unary_fp)
2638      << OrigArg->getType() << OrigArg->getSourceRange();
2639
2640  // If this is an implicit conversion from float -> double, remove it.
2641  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
2642    Expr *CastArg = Cast->getSubExpr();
2643    if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
2644      assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
2645             "promotion from float to double is the only expected cast here");
2646      Cast->setSubExpr(nullptr);
2647      TheCall->setArg(NumArgs-1, CastArg);
2648    }
2649  }
2650
2651  return false;
2652}
2653
2654/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
2655// This is declared to take (...), so we have to check everything.
2656ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
2657  if (TheCall->getNumArgs() < 2)
2658    return ExprError(Diag(TheCall->getLocEnd(),
2659                          diag::err_typecheck_call_too_few_args_at_least)
2660                     << 0 /*function call*/ << 2 << TheCall->getNumArgs()
2661                     << TheCall->getSourceRange());
2662
2663  // Determine which of the following types of shufflevector we're checking:
2664  // 1) unary, vector mask: (lhs, mask)
2665  // 2) binary, vector mask: (lhs, rhs, mask)
2666  // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
2667  QualType resType = TheCall->getArg(0)->getType();
2668  unsigned numElements = 0;
2669
2670  if (!TheCall->getArg(0)->isTypeDependent() &&
2671      !TheCall->getArg(1)->isTypeDependent()) {
2672    QualType LHSType = TheCall->getArg(0)->getType();
2673    QualType RHSType = TheCall->getArg(1)->getType();
2674
2675    if (!LHSType->isVectorType() || !RHSType->isVectorType())
2676      return ExprError(Diag(TheCall->getLocStart(),
2677                            diag::err_shufflevector_non_vector)
2678                       << SourceRange(TheCall->getArg(0)->getLocStart(),
2679                                      TheCall->getArg(1)->getLocEnd()));
2680
2681    numElements = LHSType->getAs<VectorType>()->getNumElements();
2682    unsigned numResElements = TheCall->getNumArgs() - 2;
2683
2684    // Check to see if we have a call with 2 vector arguments, the unary shuffle
2685    // with mask.  If so, verify that RHS is an integer vector type with the
2686    // same number of elts as lhs.
2687    if (TheCall->getNumArgs() == 2) {
2688      if (!RHSType->hasIntegerRepresentation() ||
2689          RHSType->getAs<VectorType>()->getNumElements() != numElements)
2690        return ExprError(Diag(TheCall->getLocStart(),
2691                              diag::err_shufflevector_incompatible_vector)
2692                         << SourceRange(TheCall->getArg(1)->getLocStart(),
2693                                        TheCall->getArg(1)->getLocEnd()));
2694    } else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
2695      return ExprError(Diag(TheCall->getLocStart(),
2696                            diag::err_shufflevector_incompatible_vector)
2697                       << SourceRange(TheCall->getArg(0)->getLocStart(),
2698                                      TheCall->getArg(1)->getLocEnd()));
2699    } else if (numElements != numResElements) {
2700      QualType eltType = LHSType->getAs<VectorType>()->getElementType();
2701      resType = Context.getVectorType(eltType, numResElements,
2702                                      VectorType::GenericVector);
2703    }
2704  }
2705
2706  for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
2707    if (TheCall->getArg(i)->isTypeDependent() ||
2708        TheCall->getArg(i)->isValueDependent())
2709      continue;
2710
2711    llvm::APSInt Result(32);
2712    if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
2713      return ExprError(Diag(TheCall->getLocStart(),
2714                            diag::err_shufflevector_nonconstant_argument)
2715                       << TheCall->getArg(i)->getSourceRange());
2716
2717    // Allow -1 which will be translated to undef in the IR.
2718    if (Result.isSigned() && Result.isAllOnesValue())
2719      continue;
2720
2721    if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
2722      return ExprError(Diag(TheCall->getLocStart(),
2723                            diag::err_shufflevector_argument_too_large)
2724                       << TheCall->getArg(i)->getSourceRange());
2725  }
2726
2727  SmallVector<Expr*, 32> exprs;
2728
2729  for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
2730    exprs.push_back(TheCall->getArg(i));
2731    TheCall->setArg(i, nullptr);
2732  }
2733
2734  return new (Context) ShuffleVectorExpr(Context, exprs, resType,
2735                                         TheCall->getCallee()->getLocStart(),
2736                                         TheCall->getRParenLoc());
2737}
2738
2739/// SemaConvertVectorExpr - Handle __builtin_convertvector
2740ExprResult Sema::SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo,
2741                                       SourceLocation BuiltinLoc,
2742                                       SourceLocation RParenLoc) {
2743  ExprValueKind VK = VK_RValue;
2744  ExprObjectKind OK = OK_Ordinary;
2745  QualType DstTy = TInfo->getType();
2746  QualType SrcTy = E->getType();
2747
2748  if (!SrcTy->isVectorType() && !SrcTy->isDependentType())
2749    return ExprError(Diag(BuiltinLoc,
2750                          diag::err_convertvector_non_vector)
2751                     << E->getSourceRange());
2752  if (!DstTy->isVectorType() && !DstTy->isDependentType())
2753    return ExprError(Diag(BuiltinLoc,
2754                          diag::err_convertvector_non_vector_type));
2755
2756  if (!SrcTy->isDependentType() && !DstTy->isDependentType()) {
2757    unsigned SrcElts = SrcTy->getAs<VectorType>()->getNumElements();
2758    unsigned DstElts = DstTy->getAs<VectorType>()->getNumElements();
2759    if (SrcElts != DstElts)
2760      return ExprError(Diag(BuiltinLoc,
2761                            diag::err_convertvector_incompatible_vector)
2762                       << E->getSourceRange());
2763  }
2764
2765  return new (Context)
2766      ConvertVectorExpr(E, TInfo, DstTy, VK, OK, BuiltinLoc, RParenLoc);
2767}
2768
2769/// SemaBuiltinPrefetch - Handle __builtin_prefetch.
2770// This is declared to take (const void*, ...) and can take two
2771// optional constant int args.
2772bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
2773  unsigned NumArgs = TheCall->getNumArgs();
2774
2775  if (NumArgs > 3)
2776    return Diag(TheCall->getLocEnd(),
2777             diag::err_typecheck_call_too_many_args_at_most)
2778             << 0 /*function call*/ << 3 << NumArgs
2779             << TheCall->getSourceRange();
2780
2781  // Argument 0 is checked for us and the remaining arguments must be
2782  // constant integers.
2783  for (unsigned i = 1; i != NumArgs; ++i)
2784    if (SemaBuiltinConstantArgRange(TheCall, i, 0, i == 1 ? 1 : 3))
2785      return true;
2786
2787  return false;
2788}
2789
2790/// SemaBuiltinAssume - Handle __assume (MS Extension).
2791// __assume does not evaluate its arguments, and should warn if its argument
2792// has side effects.
2793bool Sema::SemaBuiltinAssume(CallExpr *TheCall) {
2794  Expr *Arg = TheCall->getArg(0);
2795  if (Arg->isInstantiationDependent()) return false;
2796
2797  if (Arg->HasSideEffects(Context))
2798    Diag(Arg->getLocStart(), diag::warn_assume_side_effects)
2799      << Arg->getSourceRange()
2800      << cast<FunctionDecl>(TheCall->getCalleeDecl())->getIdentifier();
2801
2802  return false;
2803}
2804
2805/// Handle __builtin_assume_aligned. This is declared
2806/// as (const void*, size_t, ...) and can take one optional constant int arg.
2807bool Sema::SemaBuiltinAssumeAligned(CallExpr *TheCall) {
2808  unsigned NumArgs = TheCall->getNumArgs();
2809
2810  if (NumArgs > 3)
2811    return Diag(TheCall->getLocEnd(),
2812             diag::err_typecheck_call_too_many_args_at_most)
2813             << 0 /*function call*/ << 3 << NumArgs
2814             << TheCall->getSourceRange();
2815
2816  // The alignment must be a constant integer.
2817  Expr *Arg = TheCall->getArg(1);
2818
2819  // We can't check the value of a dependent argument.
2820  if (!Arg->isTypeDependent() && !Arg->isValueDependent()) {
2821    llvm::APSInt Result;
2822    if (SemaBuiltinConstantArg(TheCall, 1, Result))
2823      return true;
2824
2825    if (!Result.isPowerOf2())
2826      return Diag(TheCall->getLocStart(),
2827                  diag::err_alignment_not_power_of_two)
2828           << Arg->getSourceRange();
2829  }
2830
2831  if (NumArgs > 2) {
2832    ExprResult Arg(TheCall->getArg(2));
2833    InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
2834      Context.getSizeType(), false);
2835    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
2836    if (Arg.isInvalid()) return true;
2837    TheCall->setArg(2, Arg.get());
2838  }
2839
2840  return false;
2841}
2842
2843/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
2844/// TheCall is a constant expression.
2845bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
2846                                  llvm::APSInt &Result) {
2847  Expr *Arg = TheCall->getArg(ArgNum);
2848  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
2849  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
2850
2851  if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
2852
2853  if (!Arg->isIntegerConstantExpr(Result, Context))
2854    return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
2855                << FDecl->getDeclName() <<  Arg->getSourceRange();
2856
2857  return false;
2858}
2859
2860/// SemaBuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr
2861/// TheCall is a constant expression in the range [Low, High].
2862bool Sema::SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum,
2863                                       int Low, int High) {
2864  llvm::APSInt Result;
2865
2866  // We can't check the value of a dependent argument.
2867  Expr *Arg = TheCall->getArg(ArgNum);
2868  if (Arg->isTypeDependent() || Arg->isValueDependent())
2869    return false;
2870
2871  // Check constant-ness first.
2872  if (SemaBuiltinConstantArg(TheCall, ArgNum, Result))
2873    return true;
2874
2875  if (Result.getSExtValue() < Low || Result.getSExtValue() > High)
2876    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
2877      << Low << High << Arg->getSourceRange();
2878
2879  return false;
2880}
2881
2882/// SemaBuiltinARMSpecialReg - Handle a check if argument ArgNum of CallExpr
2883/// TheCall is an ARM/AArch64 special register string literal.
2884bool Sema::SemaBuiltinARMSpecialReg(unsigned BuiltinID, CallExpr *TheCall,
2885                                    int ArgNum, unsigned ExpectedFieldNum,
2886                                    bool AllowName) {
2887  bool IsARMBuiltin = BuiltinID == ARM::BI__builtin_arm_rsr64 ||
2888                      BuiltinID == ARM::BI__builtin_arm_wsr64 ||
2889                      BuiltinID == ARM::BI__builtin_arm_rsr ||
2890                      BuiltinID == ARM::BI__builtin_arm_rsrp ||
2891                      BuiltinID == ARM::BI__builtin_arm_wsr ||
2892                      BuiltinID == ARM::BI__builtin_arm_wsrp;
2893  bool IsAArch64Builtin = BuiltinID == AArch64::BI__builtin_arm_rsr64 ||
2894                          BuiltinID == AArch64::BI__builtin_arm_wsr64 ||
2895                          BuiltinID == AArch64::BI__builtin_arm_rsr ||
2896                          BuiltinID == AArch64::BI__builtin_arm_rsrp ||
2897                          BuiltinID == AArch64::BI__builtin_arm_wsr ||
2898                          BuiltinID == AArch64::BI__builtin_arm_wsrp;
2899  assert((IsARMBuiltin || IsAArch64Builtin) && "Unexpected ARM builtin.");
2900
2901  // We can't check the value of a dependent argument.
2902  Expr *Arg = TheCall->getArg(ArgNum);
2903  if (Arg->isTypeDependent() || Arg->isValueDependent())
2904    return false;
2905
2906  // Check if the argument is a string literal.
2907  if (!isa<StringLiteral>(Arg->IgnoreParenImpCasts()))
2908    return Diag(TheCall->getLocStart(), diag::err_expr_not_string_literal)
2909           << Arg->getSourceRange();
2910
2911  // Check the type of special register given.
2912  StringRef Reg = cast<StringLiteral>(Arg->IgnoreParenImpCasts())->getString();
2913  SmallVector<StringRef, 6> Fields;
2914  Reg.split(Fields, ":");
2915
2916  if (Fields.size() != ExpectedFieldNum && !(AllowName && Fields.size() == 1))
2917    return Diag(TheCall->getLocStart(), diag::err_arm_invalid_specialreg)
2918           << Arg->getSourceRange();
2919
2920  // If the string is the name of a register then we cannot check that it is
2921  // valid here but if the string is of one the forms described in ACLE then we
2922  // can check that the supplied fields are integers and within the valid
2923  // ranges.
2924  if (Fields.size() > 1) {
2925    bool FiveFields = Fields.size() == 5;
2926
2927    bool ValidString = true;
2928    if (IsARMBuiltin) {
2929      ValidString &= Fields[0].startswith_lower("cp") ||
2930                     Fields[0].startswith_lower("p");
2931      if (ValidString)
2932        Fields[0] =
2933          Fields[0].drop_front(Fields[0].startswith_lower("cp") ? 2 : 1);
2934
2935      ValidString &= Fields[2].startswith_lower("c");
2936      if (ValidString)
2937        Fields[2] = Fields[2].drop_front(1);
2938
2939      if (FiveFields) {
2940        ValidString &= Fields[3].startswith_lower("c");
2941        if (ValidString)
2942          Fields[3] = Fields[3].drop_front(1);
2943      }
2944    }
2945
2946    SmallVector<int, 5> Ranges;
2947    if (FiveFields)
2948      Ranges.append({IsAArch64Builtin ? 1 : 15, 7, 7, 15, 15});
2949    else
2950      Ranges.append({15, 7, 15});
2951
2952    for (unsigned i=0; i<Fields.size(); ++i) {
2953      int IntField;
2954      ValidString &= !Fields[i].getAsInteger(10, IntField);
2955      ValidString &= (IntField >= 0 && IntField <= Ranges[i]);
2956    }
2957
2958    if (!ValidString)
2959      return Diag(TheCall->getLocStart(), diag::err_arm_invalid_specialreg)
2960             << Arg->getSourceRange();
2961
2962  } else if (IsAArch64Builtin && Fields.size() == 1) {
2963    // If the register name is one of those that appear in the condition below
2964    // and the special register builtin being used is one of the write builtins,
2965    // then we require that the argument provided for writing to the register
2966    // is an integer constant expression. This is because it will be lowered to
2967    // an MSR (immediate) instruction, so we need to know the immediate at
2968    // compile time.
2969    if (TheCall->getNumArgs() != 2)
2970      return false;
2971
2972    std::string RegLower = Reg.lower();
2973    if (RegLower != "spsel" && RegLower != "daifset" && RegLower != "daifclr" &&
2974        RegLower != "pan" && RegLower != "uao")
2975      return false;
2976
2977    return SemaBuiltinConstantArgRange(TheCall, 1, 0, 15);
2978  }
2979
2980  return false;
2981}
2982
2983/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
2984/// This checks that the target supports __builtin_longjmp and
2985/// that val is a constant 1.
2986bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
2987  if (!Context.getTargetInfo().hasSjLjLowering())
2988    return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_unsupported)
2989             << SourceRange(TheCall->getLocStart(), TheCall->getLocEnd());
2990
2991  Expr *Arg = TheCall->getArg(1);
2992  llvm::APSInt Result;
2993
2994  // TODO: This is less than ideal. Overload this to take a value.
2995  if (SemaBuiltinConstantArg(TheCall, 1, Result))
2996    return true;
2997
2998  if (Result != 1)
2999    return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
3000             << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
3001
3002  return false;
3003}
3004
3005
3006/// SemaBuiltinSetjmp - Handle __builtin_setjmp(void *env[5]).
3007/// This checks that the target supports __builtin_setjmp.
3008bool Sema::SemaBuiltinSetjmp(CallExpr *TheCall) {
3009  if (!Context.getTargetInfo().hasSjLjLowering())
3010    return Diag(TheCall->getLocStart(), diag::err_builtin_setjmp_unsupported)
3011             << SourceRange(TheCall->getLocStart(), TheCall->getLocEnd());
3012  return false;
3013}
3014
3015namespace {
3016enum StringLiteralCheckType {
3017  SLCT_NotALiteral,
3018  SLCT_UncheckedLiteral,
3019  SLCT_CheckedLiteral
3020};
3021}
3022
3023// Determine if an expression is a string literal or constant string.
3024// If this function returns false on the arguments to a function expecting a
3025// format string, we will usually need to emit a warning.
3026// True string literals are then checked by CheckFormatString.
3027static StringLiteralCheckType
3028checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args,
3029                      bool HasVAListArg, unsigned format_idx,
3030                      unsigned firstDataArg, Sema::FormatStringType Type,
3031                      Sema::VariadicCallType CallType, bool InFunctionCall,
3032                      llvm::SmallBitVector &CheckedVarArgs) {
3033 tryAgain:
3034  if (E->isTypeDependent() || E->isValueDependent())
3035    return SLCT_NotALiteral;
3036
3037  E = E->IgnoreParenCasts();
3038
3039  if (E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull))
3040    // Technically -Wformat-nonliteral does not warn about this case.
3041    // The behavior of printf and friends in this case is implementation
3042    // dependent.  Ideally if the format string cannot be null then
3043    // it should have a 'nonnull' attribute in the function prototype.
3044    return SLCT_UncheckedLiteral;
3045
3046  switch (E->getStmtClass()) {
3047  case Stmt::BinaryConditionalOperatorClass:
3048  case Stmt::ConditionalOperatorClass: {
3049    // The expression is a literal if both sub-expressions were, and it was
3050    // completely checked only if both sub-expressions were checked.
3051    const AbstractConditionalOperator *C =
3052        cast<AbstractConditionalOperator>(E);
3053    StringLiteralCheckType Left =
3054        checkFormatStringExpr(S, C->getTrueExpr(), Args,
3055                              HasVAListArg, format_idx, firstDataArg,
3056                              Type, CallType, InFunctionCall, CheckedVarArgs);
3057    if (Left == SLCT_NotALiteral)
3058      return SLCT_NotALiteral;
3059    StringLiteralCheckType Right =
3060        checkFormatStringExpr(S, C->getFalseExpr(), Args,
3061                              HasVAListArg, format_idx, firstDataArg,
3062                              Type, CallType, InFunctionCall, CheckedVarArgs);
3063    return Left < Right ? Left : Right;
3064  }
3065
3066  case Stmt::ImplicitCastExprClass: {
3067    E = cast<ImplicitCastExpr>(E)->getSubExpr();
3068    goto tryAgain;
3069  }
3070
3071  case Stmt::OpaqueValueExprClass:
3072    if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
3073      E = src;
3074      goto tryAgain;
3075    }
3076    return SLCT_NotALiteral;
3077
3078  case Stmt::PredefinedExprClass:
3079    // While __func__, etc., are technically not string literals, they
3080    // cannot contain format specifiers and thus are not a security
3081    // liability.
3082    return SLCT_UncheckedLiteral;
3083
3084  case Stmt::DeclRefExprClass: {
3085    const DeclRefExpr *DR = cast<DeclRefExpr>(E);
3086
3087    // As an exception, do not flag errors for variables binding to
3088    // const string literals.
3089    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
3090      bool isConstant = false;
3091      QualType T = DR->getType();
3092
3093      if (const ArrayType *AT = S.Context.getAsArrayType(T)) {
3094        isConstant = AT->getElementType().isConstant(S.Context);
3095      } else if (const PointerType *PT = T->getAs<PointerType>()) {
3096        isConstant = T.isConstant(S.Context) &&
3097                     PT->getPointeeType().isConstant(S.Context);
3098      } else if (T->isObjCObjectPointerType()) {
3099        // In ObjC, there is usually no "const ObjectPointer" type,
3100        // so don't check if the pointee type is constant.
3101        isConstant = T.isConstant(S.Context);
3102      }
3103
3104      if (isConstant) {
3105        if (const Expr *Init = VD->getAnyInitializer()) {
3106          // Look through initializers like const char c[] = { "foo" }
3107          if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
3108            if (InitList->isStringLiteralInit())
3109              Init = InitList->getInit(0)->IgnoreParenImpCasts();
3110          }
3111          return checkFormatStringExpr(S, Init, Args,
3112                                       HasVAListArg, format_idx,
3113                                       firstDataArg, Type, CallType,
3114                                       /*InFunctionCall*/false, CheckedVarArgs);
3115        }
3116      }
3117
3118      // For vprintf* functions (i.e., HasVAListArg==true), we add a
3119      // special check to see if the format string is a function parameter
3120      // of the function calling the printf function.  If the function
3121      // has an attribute indicating it is a printf-like function, then we
3122      // should suppress warnings concerning non-literals being used in a call
3123      // to a vprintf function.  For example:
3124      //
3125      // void
3126      // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
3127      //      va_list ap;
3128      //      va_start(ap, fmt);
3129      //      vprintf(fmt, ap);  // Do NOT emit a warning about "fmt".
3130      //      ...
3131      // }
3132      if (HasVAListArg) {
3133        if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) {
3134          if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) {
3135            int PVIndex = PV->getFunctionScopeIndex() + 1;
3136            for (const auto *PVFormat : ND->specific_attrs<FormatAttr>()) {
3137              // adjust for implicit parameter
3138              if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
3139                if (MD->isInstance())
3140                  ++PVIndex;
3141              // We also check if the formats are compatible.
3142              // We can't pass a 'scanf' string to a 'printf' function.
3143              if (PVIndex == PVFormat->getFormatIdx() &&
3144                  Type == S.GetFormatStringType(PVFormat))
3145                return SLCT_UncheckedLiteral;
3146            }
3147          }
3148        }
3149      }
3150    }
3151
3152    return SLCT_NotALiteral;
3153  }
3154
3155  case Stmt::CallExprClass:
3156  case Stmt::CXXMemberCallExprClass: {
3157    const CallExpr *CE = cast<CallExpr>(E);
3158    if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
3159      if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
3160        unsigned ArgIndex = FA->getFormatIdx();
3161        if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
3162          if (MD->isInstance())
3163            --ArgIndex;
3164        const Expr *Arg = CE->getArg(ArgIndex - 1);
3165
3166        return checkFormatStringExpr(S, Arg, Args,
3167                                     HasVAListArg, format_idx, firstDataArg,
3168                                     Type, CallType, InFunctionCall,
3169                                     CheckedVarArgs);
3170      } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
3171        unsigned BuiltinID = FD->getBuiltinID();
3172        if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
3173            BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
3174          const Expr *Arg = CE->getArg(0);
3175          return checkFormatStringExpr(S, Arg, Args,
3176                                       HasVAListArg, format_idx,
3177                                       firstDataArg, Type, CallType,
3178                                       InFunctionCall, CheckedVarArgs);
3179        }
3180      }
3181    }
3182
3183    return SLCT_NotALiteral;
3184  }
3185  case Stmt::ObjCStringLiteralClass:
3186  case Stmt::StringLiteralClass: {
3187    const StringLiteral *StrE = nullptr;
3188
3189    if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
3190      StrE = ObjCFExpr->getString();
3191    else
3192      StrE = cast<StringLiteral>(E);
3193
3194    if (StrE) {
3195      S.CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, firstDataArg,
3196                          Type, InFunctionCall, CallType, CheckedVarArgs);
3197      return SLCT_CheckedLiteral;
3198    }
3199
3200    return SLCT_NotALiteral;
3201  }
3202
3203  default:
3204    return SLCT_NotALiteral;
3205  }
3206}
3207
3208Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
3209  return llvm::StringSwitch<FormatStringType>(Format->getType()->getName())
3210  .Case("scanf", FST_Scanf)
3211  .Cases("printf", "printf0", FST_Printf)
3212  .Cases("NSString", "CFString", FST_NSString)
3213  .Case("strftime", FST_Strftime)
3214  .Case("strfmon", FST_Strfmon)
3215  .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
3216  .Case("freebsd_kprintf", FST_FreeBSDKPrintf)
3217  .Case("os_trace", FST_OSTrace)
3218  .Default(FST_Unknown);
3219}
3220
3221/// CheckFormatArguments - Check calls to printf and scanf (and similar
3222/// functions) for correct use of format strings.
3223/// Returns true if a format string has been fully checked.
3224bool Sema::CheckFormatArguments(const FormatAttr *Format,
3225                                ArrayRef<const Expr *> Args,
3226                                bool IsCXXMember,
3227                                VariadicCallType CallType,
3228                                SourceLocation Loc, SourceRange Range,
3229                                llvm::SmallBitVector &CheckedVarArgs) {
3230  FormatStringInfo FSI;
3231  if (getFormatStringInfo(Format, IsCXXMember, &FSI))
3232    return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx,
3233                                FSI.FirstDataArg, GetFormatStringType(Format),
3234                                CallType, Loc, Range, CheckedVarArgs);
3235  return false;
3236}
3237
3238bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args,
3239                                bool HasVAListArg, unsigned format_idx,
3240                                unsigned firstDataArg, FormatStringType Type,
3241                                VariadicCallType CallType,
3242                                SourceLocation Loc, SourceRange Range,
3243                                llvm::SmallBitVector &CheckedVarArgs) {
3244  // CHECK: printf/scanf-like function is called with no format string.
3245  if (format_idx >= Args.size()) {
3246    Diag(Loc, diag::warn_missing_format_string) << Range;
3247    return false;
3248  }
3249
3250  const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
3251
3252  // CHECK: format string is not a string literal.
3253  //
3254  // Dynamically generated format strings are difficult to
3255  // automatically vet at compile time.  Requiring that format strings
3256  // are string literals: (1) permits the checking of format strings by
3257  // the compiler and thereby (2) can practically remove the source of
3258  // many format string exploits.
3259
3260  // Format string can be either ObjC string (e.g. @"%d") or
3261  // C string (e.g. "%d")
3262  // ObjC string uses the same format specifiers as C string, so we can use
3263  // the same format string checking logic for both ObjC and C strings.
3264  StringLiteralCheckType CT =
3265      checkFormatStringExpr(*this, OrigFormatExpr, Args, HasVAListArg,
3266                            format_idx, firstDataArg, Type, CallType,
3267                            /*IsFunctionCall*/true, CheckedVarArgs);
3268  if (CT != SLCT_NotALiteral)
3269    // Literal format string found, check done!
3270    return CT == SLCT_CheckedLiteral;
3271
3272  // Strftime is particular as it always uses a single 'time' argument,
3273  // so it is safe to pass a non-literal string.
3274  if (Type == FST_Strftime)
3275    return false;
3276
3277  // Do not emit diag when the string param is a macro expansion and the
3278  // format is either NSString or CFString. This is a hack to prevent
3279  // diag when using the NSLocalizedString and CFCopyLocalizedString macros
3280  // which are usually used in place of NS and CF string literals.
3281  if (Type == FST_NSString &&
3282      SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart()))
3283    return false;
3284
3285  // If there are no arguments specified, warn with -Wformat-security, otherwise
3286  // warn only with -Wformat-nonliteral.
3287  if (Args.size() == firstDataArg)
3288    Diag(Args[format_idx]->getLocStart(),
3289         diag::warn_format_nonliteral_noargs)
3290      << OrigFormatExpr->getSourceRange();
3291  else
3292    Diag(Args[format_idx]->getLocStart(),
3293         diag::warn_format_nonliteral)
3294           << OrigFormatExpr->getSourceRange();
3295  return false;
3296}
3297
3298namespace {
3299class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
3300protected:
3301  Sema &S;
3302  const StringLiteral *FExpr;
3303  const Expr *OrigFormatExpr;
3304  const unsigned FirstDataArg;
3305  const unsigned NumDataArgs;
3306  const char *Beg; // Start of format string.
3307  const bool HasVAListArg;
3308  ArrayRef<const Expr *> Args;
3309  unsigned FormatIdx;
3310  llvm::SmallBitVector CoveredArgs;
3311  bool usesPositionalArgs;
3312  bool atFirstArg;
3313  bool inFunctionCall;
3314  Sema::VariadicCallType CallType;
3315  llvm::SmallBitVector &CheckedVarArgs;
3316public:
3317  CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
3318                     const Expr *origFormatExpr, unsigned firstDataArg,
3319                     unsigned numDataArgs, const char *beg, bool hasVAListArg,
3320                     ArrayRef<const Expr *> Args,
3321                     unsigned formatIdx, bool inFunctionCall,
3322                     Sema::VariadicCallType callType,
3323                     llvm::SmallBitVector &CheckedVarArgs)
3324    : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
3325      FirstDataArg(firstDataArg), NumDataArgs(numDataArgs),
3326      Beg(beg), HasVAListArg(hasVAListArg),
3327      Args(Args), FormatIdx(formatIdx),
3328      usesPositionalArgs(false), atFirstArg(true),
3329      inFunctionCall(inFunctionCall), CallType(callType),
3330      CheckedVarArgs(CheckedVarArgs) {
3331    CoveredArgs.resize(numDataArgs);
3332    CoveredArgs.reset();
3333  }
3334
3335  void DoneProcessing();
3336
3337  void HandleIncompleteSpecifier(const char *startSpecifier,
3338                                 unsigned specifierLen) override;
3339
3340  void HandleInvalidLengthModifier(
3341                           const analyze_format_string::FormatSpecifier &FS,
3342                           const analyze_format_string::ConversionSpecifier &CS,
3343                           const char *startSpecifier, unsigned specifierLen,
3344                           unsigned DiagID);
3345
3346  void HandleNonStandardLengthModifier(
3347                    const analyze_format_string::FormatSpecifier &FS,
3348                    const char *startSpecifier, unsigned specifierLen);
3349
3350  void HandleNonStandardConversionSpecifier(
3351                    const analyze_format_string::ConversionSpecifier &CS,
3352                    const char *startSpecifier, unsigned specifierLen);
3353
3354  void HandlePosition(const char *startPos, unsigned posLen) override;
3355
3356  void HandleInvalidPosition(const char *startSpecifier,
3357                             unsigned specifierLen,
3358                             analyze_format_string::PositionContext p) override;
3359
3360  void HandleZeroPosition(const char *startPos, unsigned posLen) override;
3361
3362  void HandleNullChar(const char *nullCharacter) override;
3363
3364  template <typename Range>
3365  static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall,
3366                                   const Expr *ArgumentExpr,
3367                                   PartialDiagnostic PDiag,
3368                                   SourceLocation StringLoc,
3369                                   bool IsStringLocation, Range StringRange,
3370                                   ArrayRef<FixItHint> Fixit = None);
3371
3372protected:
3373  bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
3374                                        const char *startSpec,
3375                                        unsigned specifierLen,
3376                                        const char *csStart, unsigned csLen);
3377
3378  void HandlePositionalNonpositionalArgs(SourceLocation Loc,
3379                                         const char *startSpec,
3380                                         unsigned specifierLen);
3381
3382  SourceRange getFormatStringRange();
3383  CharSourceRange getSpecifierRange(const char *startSpecifier,
3384                                    unsigned specifierLen);
3385  SourceLocation getLocationOfByte(const char *x);
3386
3387  const Expr *getDataArg(unsigned i) const;
3388
3389  bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
3390                    const analyze_format_string::ConversionSpecifier &CS,
3391                    const char *startSpecifier, unsigned specifierLen,
3392                    unsigned argIndex);
3393
3394  template <typename Range>
3395  void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
3396                            bool IsStringLocation, Range StringRange,
3397                            ArrayRef<FixItHint> Fixit = None);
3398};
3399}
3400
3401SourceRange CheckFormatHandler::getFormatStringRange() {
3402  return OrigFormatExpr->getSourceRange();
3403}
3404
3405CharSourceRange CheckFormatHandler::
3406getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
3407  SourceLocation Start = getLocationOfByte(startSpecifier);
3408  SourceLocation End   = getLocationOfByte(startSpecifier + specifierLen - 1);
3409
3410  // Advance the end SourceLocation by one due to half-open ranges.
3411  End = End.getLocWithOffset(1);
3412
3413  return CharSourceRange::getCharRange(Start, End);
3414}
3415
3416SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
3417  return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
3418}
3419
3420void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
3421                                                   unsigned specifierLen){
3422  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
3423                       getLocationOfByte(startSpecifier),
3424                       /*IsStringLocation*/true,
3425                       getSpecifierRange(startSpecifier, specifierLen));
3426}
3427
3428void CheckFormatHandler::HandleInvalidLengthModifier(
3429    const analyze_format_string::FormatSpecifier &FS,
3430    const analyze_format_string::ConversionSpecifier &CS,
3431    const char *startSpecifier, unsigned specifierLen, unsigned DiagID) {
3432  using namespace analyze_format_string;
3433
3434  const LengthModifier &LM = FS.getLengthModifier();
3435  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
3436
3437  // See if we know how to fix this length modifier.
3438  Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
3439  if (FixedLM) {
3440    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
3441                         getLocationOfByte(LM.getStart()),
3442                         /*IsStringLocation*/true,
3443                         getSpecifierRange(startSpecifier, specifierLen));
3444
3445    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
3446      << FixedLM->toString()
3447      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
3448
3449  } else {
3450    FixItHint Hint;
3451    if (DiagID == diag::warn_format_nonsensical_length)
3452      Hint = FixItHint::CreateRemoval(LMRange);
3453
3454    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
3455                         getLocationOfByte(LM.getStart()),
3456                         /*IsStringLocation*/true,
3457                         getSpecifierRange(startSpecifier, specifierLen),
3458                         Hint);
3459  }
3460}
3461
3462void CheckFormatHandler::HandleNonStandardLengthModifier(
3463    const analyze_format_string::FormatSpecifier &FS,
3464    const char *startSpecifier, unsigned specifierLen) {
3465  using namespace analyze_format_string;
3466
3467  const LengthModifier &LM = FS.getLengthModifier();
3468  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
3469
3470  // See if we know how to fix this length modifier.
3471  Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
3472  if (FixedLM) {
3473    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
3474                           << LM.toString() << 0,
3475                         getLocationOfByte(LM.getStart()),
3476                         /*IsStringLocation*/true,
3477                         getSpecifierRange(startSpecifier, specifierLen));
3478
3479    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
3480      << FixedLM->toString()
3481      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
3482
3483  } else {
3484    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
3485                           << LM.toString() << 0,
3486                         getLocationOfByte(LM.getStart()),
3487                         /*IsStringLocation*/true,
3488                         getSpecifierRange(startSpecifier, specifierLen));
3489  }
3490}
3491
3492void CheckFormatHandler::HandleNonStandardConversionSpecifier(
3493    const analyze_format_string::ConversionSpecifier &CS,
3494    const char *startSpecifier, unsigned specifierLen) {
3495  using namespace analyze_format_string;
3496
3497  // See if we know how to fix this conversion specifier.
3498  Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier();
3499  if (FixedCS) {
3500    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
3501                          << CS.toString() << /*conversion specifier*/1,
3502                         getLocationOfByte(CS.getStart()),
3503                         /*IsStringLocation*/true,
3504                         getSpecifierRange(startSpecifier, specifierLen));
3505
3506    CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength());
3507    S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier)
3508      << FixedCS->toString()
3509      << FixItHint::CreateReplacement(CSRange, FixedCS->toString());
3510  } else {
3511    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
3512                          << CS.toString() << /*conversion specifier*/1,
3513                         getLocationOfByte(CS.getStart()),
3514                         /*IsStringLocation*/true,
3515                         getSpecifierRange(startSpecifier, specifierLen));
3516  }
3517}
3518
3519void CheckFormatHandler::HandlePosition(const char *startPos,
3520                                        unsigned posLen) {
3521  EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
3522                               getLocationOfByte(startPos),
3523                               /*IsStringLocation*/true,
3524                               getSpecifierRange(startPos, posLen));
3525}
3526
3527void
3528CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
3529                                     analyze_format_string::PositionContext p) {
3530  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
3531                         << (unsigned) p,
3532                       getLocationOfByte(startPos), /*IsStringLocation*/true,
3533                       getSpecifierRange(startPos, posLen));
3534}
3535
3536void CheckFormatHandler::HandleZeroPosition(const char *startPos,
3537                                            unsigned posLen) {
3538  EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
3539                               getLocationOfByte(startPos),
3540                               /*IsStringLocation*/true,
3541                               getSpecifierRange(startPos, posLen));
3542}
3543
3544void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
3545  if (!isa<ObjCStringLiteral>(OrigFormatExpr)) {
3546    // The presence of a null character is likely an error.
3547    EmitFormatDiagnostic(
3548      S.PDiag(diag::warn_printf_format_string_contains_null_char),
3549      getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
3550      getFormatStringRange());
3551  }
3552}
3553
3554// Note that this may return NULL if there was an error parsing or building
3555// one of the argument expressions.
3556const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
3557  return Args[FirstDataArg + i];
3558}
3559
3560void CheckFormatHandler::DoneProcessing() {
3561    // Does the number of data arguments exceed the number of
3562    // format conversions in the format string?
3563  if (!HasVAListArg) {
3564      // Find any arguments that weren't covered.
3565    CoveredArgs.flip();
3566    signed notCoveredArg = CoveredArgs.find_first();
3567    if (notCoveredArg >= 0) {
3568      assert((unsigned)notCoveredArg < NumDataArgs);
3569      if (const Expr *E = getDataArg((unsigned) notCoveredArg)) {
3570        SourceLocation Loc = E->getLocStart();
3571        if (!S.getSourceManager().isInSystemMacro(Loc)) {
3572          EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used),
3573                               Loc, /*IsStringLocation*/false,
3574                               getFormatStringRange());
3575        }
3576      }
3577    }
3578  }
3579}
3580
3581bool
3582CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
3583                                                     SourceLocation Loc,
3584                                                     const char *startSpec,
3585                                                     unsigned specifierLen,
3586                                                     const char *csStart,
3587                                                     unsigned csLen) {
3588
3589  bool keepGoing = true;
3590  if (argIndex < NumDataArgs) {
3591    // Consider the argument coverered, even though the specifier doesn't
3592    // make sense.
3593    CoveredArgs.set(argIndex);
3594  }
3595  else {
3596    // If argIndex exceeds the number of data arguments we
3597    // don't issue a warning because that is just a cascade of warnings (and
3598    // they may have intended '%%' anyway). We don't want to continue processing
3599    // the format string after this point, however, as we will like just get
3600    // gibberish when trying to match arguments.
3601    keepGoing = false;
3602  }
3603
3604  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
3605                         << StringRef(csStart, csLen),
3606                       Loc, /*IsStringLocation*/true,
3607                       getSpecifierRange(startSpec, specifierLen));
3608
3609  return keepGoing;
3610}
3611
3612void
3613CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
3614                                                      const char *startSpec,
3615                                                      unsigned specifierLen) {
3616  EmitFormatDiagnostic(
3617    S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
3618    Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
3619}
3620
3621bool
3622CheckFormatHandler::CheckNumArgs(
3623  const analyze_format_string::FormatSpecifier &FS,
3624  const analyze_format_string::ConversionSpecifier &CS,
3625  const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
3626
3627  if (argIndex >= NumDataArgs) {
3628    PartialDiagnostic PDiag = FS.usesPositionalArg()
3629      ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
3630           << (argIndex+1) << NumDataArgs)
3631      : S.PDiag(diag::warn_printf_insufficient_data_args);
3632    EmitFormatDiagnostic(
3633      PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
3634      getSpecifierRange(startSpecifier, specifierLen));
3635    return false;
3636  }
3637  return true;
3638}
3639
3640template<typename Range>
3641void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
3642                                              SourceLocation Loc,
3643                                              bool IsStringLocation,
3644                                              Range StringRange,
3645                                              ArrayRef<FixItHint> FixIt) {
3646  EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
3647                       Loc, IsStringLocation, StringRange, FixIt);
3648}
3649
3650/// \brief If the format string is not within the funcion call, emit a note
3651/// so that the function call and string are in diagnostic messages.
3652///
3653/// \param InFunctionCall if true, the format string is within the function
3654/// call and only one diagnostic message will be produced.  Otherwise, an
3655/// extra note will be emitted pointing to location of the format string.
3656///
3657/// \param ArgumentExpr the expression that is passed as the format string
3658/// argument in the function call.  Used for getting locations when two
3659/// diagnostics are emitted.
3660///
3661/// \param PDiag the callee should already have provided any strings for the
3662/// diagnostic message.  This function only adds locations and fixits
3663/// to diagnostics.
3664///
3665/// \param Loc primary location for diagnostic.  If two diagnostics are
3666/// required, one will be at Loc and a new SourceLocation will be created for
3667/// the other one.
3668///
3669/// \param IsStringLocation if true, Loc points to the format string should be
3670/// used for the note.  Otherwise, Loc points to the argument list and will
3671/// be used with PDiag.
3672///
3673/// \param StringRange some or all of the string to highlight.  This is
3674/// templated so it can accept either a CharSourceRange or a SourceRange.
3675///
3676/// \param FixIt optional fix it hint for the format string.
3677template<typename Range>
3678void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall,
3679                                              const Expr *ArgumentExpr,
3680                                              PartialDiagnostic PDiag,
3681                                              SourceLocation Loc,
3682                                              bool IsStringLocation,
3683                                              Range StringRange,
3684                                              ArrayRef<FixItHint> FixIt) {
3685  if (InFunctionCall) {
3686    const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag);
3687    D << StringRange;
3688    D << FixIt;
3689  } else {
3690    S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
3691      << ArgumentExpr->getSourceRange();
3692
3693    const Sema::SemaDiagnosticBuilder &Note =
3694      S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
3695             diag::note_format_string_defined);
3696
3697    Note << StringRange;
3698    Note << FixIt;
3699  }
3700}
3701
3702//===--- CHECK: Printf format string checking ------------------------------===//
3703
3704namespace {
3705class CheckPrintfHandler : public CheckFormatHandler {
3706  bool ObjCContext;
3707public:
3708  CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
3709                     const Expr *origFormatExpr, unsigned firstDataArg,
3710                     unsigned numDataArgs, bool isObjC,
3711                     const char *beg, bool hasVAListArg,
3712                     ArrayRef<const Expr *> Args,
3713                     unsigned formatIdx, bool inFunctionCall,
3714                     Sema::VariadicCallType CallType,
3715                     llvm::SmallBitVector &CheckedVarArgs)
3716    : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
3717                         numDataArgs, beg, hasVAListArg, Args,
3718                         formatIdx, inFunctionCall, CallType, CheckedVarArgs),
3719      ObjCContext(isObjC)
3720  {}
3721
3722
3723  bool HandleInvalidPrintfConversionSpecifier(
3724                                      const analyze_printf::PrintfSpecifier &FS,
3725                                      const char *startSpecifier,
3726                                      unsigned specifierLen) override;
3727
3728  bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
3729                             const char *startSpecifier,
3730                             unsigned specifierLen) override;
3731  bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
3732                       const char *StartSpecifier,
3733                       unsigned SpecifierLen,
3734                       const Expr *E);
3735
3736  bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
3737                    const char *startSpecifier, unsigned specifierLen);
3738  void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
3739                           const analyze_printf::OptionalAmount &Amt,
3740                           unsigned type,
3741                           const char *startSpecifier, unsigned specifierLen);
3742  void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
3743                  const analyze_printf::OptionalFlag &flag,
3744                  const char *startSpecifier, unsigned specifierLen);
3745  void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
3746                         const analyze_printf::OptionalFlag &ignoredFlag,
3747                         const analyze_printf::OptionalFlag &flag,
3748                         const char *startSpecifier, unsigned specifierLen);
3749  bool checkForCStrMembers(const analyze_printf::ArgType &AT,
3750                           const Expr *E);
3751
3752  void HandleEmptyObjCModifierFlag(const char *startFlag,
3753                                   unsigned flagLen) override;
3754
3755  void HandleInvalidObjCModifierFlag(const char *startFlag,
3756                                            unsigned flagLen) override;
3757
3758  void HandleObjCFlagsWithNonObjCConversion(const char *flagsStart,
3759                                           const char *flagsEnd,
3760                                           const char *conversionPosition)
3761                                             override;
3762};
3763}
3764
3765bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
3766                                      const analyze_printf::PrintfSpecifier &FS,
3767                                      const char *startSpecifier,
3768                                      unsigned specifierLen) {
3769  const analyze_printf::PrintfConversionSpecifier &CS =
3770    FS.getConversionSpecifier();
3771
3772  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
3773                                          getLocationOfByte(CS.getStart()),
3774                                          startSpecifier, specifierLen,
3775                                          CS.getStart(), CS.getLength());
3776}
3777
3778bool CheckPrintfHandler::HandleAmount(
3779                               const analyze_format_string::OptionalAmount &Amt,
3780                               unsigned k, const char *startSpecifier,
3781                               unsigned specifierLen) {
3782
3783  if (Amt.hasDataArgument()) {
3784    if (!HasVAListArg) {
3785      unsigned argIndex = Amt.getArgIndex();
3786      if (argIndex >= NumDataArgs) {
3787        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
3788                               << k,
3789                             getLocationOfByte(Amt.getStart()),
3790                             /*IsStringLocation*/true,
3791                             getSpecifierRange(startSpecifier, specifierLen));
3792        // Don't do any more checking.  We will just emit
3793        // spurious errors.
3794        return false;
3795      }
3796
3797      // Type check the data argument.  It should be an 'int'.
3798      // Although not in conformance with C99, we also allow the argument to be
3799      // an 'unsigned int' as that is a reasonably safe case.  GCC also
3800      // doesn't emit a warning for that case.
3801      CoveredArgs.set(argIndex);
3802      const Expr *Arg = getDataArg(argIndex);
3803      if (!Arg)
3804        return false;
3805
3806      QualType T = Arg->getType();
3807
3808      const analyze_printf::ArgType &AT = Amt.getArgType(S.Context);
3809      assert(AT.isValid());
3810
3811      if (!AT.matchesType(S.Context, T)) {
3812        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
3813                               << k << AT.getRepresentativeTypeName(S.Context)
3814                               << T << Arg->getSourceRange(),
3815                             getLocationOfByte(Amt.getStart()),
3816                             /*IsStringLocation*/true,
3817                             getSpecifierRange(startSpecifier, specifierLen));
3818        // Don't do any more checking.  We will just emit
3819        // spurious errors.
3820        return false;
3821      }
3822    }
3823  }
3824  return true;
3825}
3826
3827void CheckPrintfHandler::HandleInvalidAmount(
3828                                      const analyze_printf::PrintfSpecifier &FS,
3829                                      const analyze_printf::OptionalAmount &Amt,
3830                                      unsigned type,
3831                                      const char *startSpecifier,
3832                                      unsigned specifierLen) {
3833  const analyze_printf::PrintfConversionSpecifier &CS =
3834    FS.getConversionSpecifier();
3835
3836  FixItHint fixit =
3837    Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
3838      ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
3839                                 Amt.getConstantLength()))
3840      : FixItHint();
3841
3842  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
3843                         << type << CS.toString(),
3844                       getLocationOfByte(Amt.getStart()),
3845                       /*IsStringLocation*/true,
3846                       getSpecifierRange(startSpecifier, specifierLen),
3847                       fixit);
3848}
3849
3850void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
3851                                    const analyze_printf::OptionalFlag &flag,
3852                                    const char *startSpecifier,
3853                                    unsigned specifierLen) {
3854  // Warn about pointless flag with a fixit removal.
3855  const analyze_printf::PrintfConversionSpecifier &CS =
3856    FS.getConversionSpecifier();
3857  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
3858                         << flag.toString() << CS.toString(),
3859                       getLocationOfByte(flag.getPosition()),
3860                       /*IsStringLocation*/true,
3861                       getSpecifierRange(startSpecifier, specifierLen),
3862                       FixItHint::CreateRemoval(
3863                         getSpecifierRange(flag.getPosition(), 1)));
3864}
3865
3866void CheckPrintfHandler::HandleIgnoredFlag(
3867                                const analyze_printf::PrintfSpecifier &FS,
3868                                const analyze_printf::OptionalFlag &ignoredFlag,
3869                                const analyze_printf::OptionalFlag &flag,
3870                                const char *startSpecifier,
3871                                unsigned specifierLen) {
3872  // Warn about ignored flag with a fixit removal.
3873  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
3874                         << ignoredFlag.toString() << flag.toString(),
3875                       getLocationOfByte(ignoredFlag.getPosition()),
3876                       /*IsStringLocation*/true,
3877                       getSpecifierRange(startSpecifier, specifierLen),
3878                       FixItHint::CreateRemoval(
3879                         getSpecifierRange(ignoredFlag.getPosition(), 1)));
3880}
3881
3882//  void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
3883//                            bool IsStringLocation, Range StringRange,
3884//                            ArrayRef<FixItHint> Fixit = None);
3885
3886void CheckPrintfHandler::HandleEmptyObjCModifierFlag(const char *startFlag,
3887                                                     unsigned flagLen) {
3888  // Warn about an empty flag.
3889  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_empty_objc_flag),
3890                       getLocationOfByte(startFlag),
3891                       /*IsStringLocation*/true,
3892                       getSpecifierRange(startFlag, flagLen));
3893}
3894
3895void CheckPrintfHandler::HandleInvalidObjCModifierFlag(const char *startFlag,
3896                                                       unsigned flagLen) {
3897  // Warn about an invalid flag.
3898  auto Range = getSpecifierRange(startFlag, flagLen);
3899  StringRef flag(startFlag, flagLen);
3900  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_invalid_objc_flag) << flag,
3901                      getLocationOfByte(startFlag),
3902                      /*IsStringLocation*/true,
3903                      Range, FixItHint::CreateRemoval(Range));
3904}
3905
3906void CheckPrintfHandler::HandleObjCFlagsWithNonObjCConversion(
3907    const char *flagsStart, const char *flagsEnd, const char *conversionPosition) {
3908    // Warn about using '[...]' without a '@' conversion.
3909    auto Range = getSpecifierRange(flagsStart, flagsEnd - flagsStart + 1);
3910    auto diag = diag::warn_printf_ObjCflags_without_ObjCConversion;
3911    EmitFormatDiagnostic(S.PDiag(diag) << StringRef(conversionPosition, 1),
3912                         getLocationOfByte(conversionPosition),
3913                         /*IsStringLocation*/true,
3914                         Range, FixItHint::CreateRemoval(Range));
3915}
3916
3917// Determines if the specified is a C++ class or struct containing
3918// a member with the specified name and kind (e.g. a CXXMethodDecl named
3919// "c_str()").
3920template<typename MemberKind>
3921static llvm::SmallPtrSet<MemberKind*, 1>
3922CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
3923  const RecordType *RT = Ty->getAs<RecordType>();
3924  llvm::SmallPtrSet<MemberKind*, 1> Results;
3925
3926  if (!RT)
3927    return Results;
3928  const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
3929  if (!RD || !RD->getDefinition())
3930    return Results;
3931
3932  LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(),
3933                 Sema::LookupMemberName);
3934  R.suppressDiagnostics();
3935
3936  // We just need to include all members of the right kind turned up by the
3937  // filter, at this point.
3938  if (S.LookupQualifiedName(R, RT->getDecl()))
3939    for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
3940      NamedDecl *decl = (*I)->getUnderlyingDecl();
3941      if (MemberKind *FK = dyn_cast<MemberKind>(decl))
3942        Results.insert(FK);
3943    }
3944  return Results;
3945}
3946
3947/// Check if we could call '.c_str()' on an object.
3948///
3949/// FIXME: This returns the wrong results in some cases (if cv-qualifiers don't
3950/// allow the call, or if it would be ambiguous).
3951bool Sema::hasCStrMethod(const Expr *E) {
3952  typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
3953  MethodSet Results =
3954      CXXRecordMembersNamed<CXXMethodDecl>("c_str", *this, E->getType());
3955  for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
3956       MI != ME; ++MI)
3957    if ((*MI)->getMinRequiredArguments() == 0)
3958      return true;
3959  return false;
3960}
3961
3962// Check if a (w)string was passed when a (w)char* was needed, and offer a
3963// better diagnostic if so. AT is assumed to be valid.
3964// Returns true when a c_str() conversion method is found.
3965bool CheckPrintfHandler::checkForCStrMembers(
3966    const analyze_printf::ArgType &AT, const Expr *E) {
3967  typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
3968
3969  MethodSet Results =
3970      CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType());
3971
3972  for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
3973       MI != ME; ++MI) {
3974    const CXXMethodDecl *Method = *MI;
3975    if (Method->getMinRequiredArguments() == 0 &&
3976        AT.matchesType(S.Context, Method->getReturnType())) {
3977      // FIXME: Suggest parens if the expression needs them.
3978      SourceLocation EndLoc = S.getLocForEndOfToken(E->getLocEnd());
3979      S.Diag(E->getLocStart(), diag::note_printf_c_str)
3980          << "c_str()"
3981          << FixItHint::CreateInsertion(EndLoc, ".c_str()");
3982      return true;
3983    }
3984  }
3985
3986  return false;
3987}
3988
3989bool
3990CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
3991                                            &FS,
3992                                          const char *startSpecifier,
3993                                          unsigned specifierLen) {
3994
3995  using namespace analyze_format_string;
3996  using namespace analyze_printf;
3997  const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
3998
3999  if (FS.consumesDataArgument()) {
4000    if (atFirstArg) {
4001        atFirstArg = false;
4002        usesPositionalArgs = FS.usesPositionalArg();
4003    }
4004    else if (usesPositionalArgs != FS.usesPositionalArg()) {
4005      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
4006                                        startSpecifier, specifierLen);
4007      return false;
4008    }
4009  }
4010
4011  // First check if the field width, precision, and conversion specifier
4012  // have matching data arguments.
4013  if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
4014                    startSpecifier, specifierLen)) {
4015    return false;
4016  }
4017
4018  if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
4019                    startSpecifier, specifierLen)) {
4020    return false;
4021  }
4022
4023  if (!CS.consumesDataArgument()) {
4024    // FIXME: Technically specifying a precision or field width here
4025    // makes no sense.  Worth issuing a warning at some point.
4026    return true;
4027  }
4028
4029  // Consume the argument.
4030  unsigned argIndex = FS.getArgIndex();
4031  if (argIndex < NumDataArgs) {
4032    // The check to see if the argIndex is valid will come later.
4033    // We set the bit here because we may exit early from this
4034    // function if we encounter some other error.
4035    CoveredArgs.set(argIndex);
4036  }
4037
4038  // FreeBSD kernel extensions.
4039  if (CS.getKind() == ConversionSpecifier::FreeBSDbArg ||
4040      CS.getKind() == ConversionSpecifier::FreeBSDDArg) {
4041    // We need at least two arguments.
4042    if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex + 1))
4043      return false;
4044
4045    // Claim the second argument.
4046    CoveredArgs.set(argIndex + 1);
4047
4048    // Type check the first argument (int for %b, pointer for %D)
4049    const Expr *Ex = getDataArg(argIndex);
4050    const analyze_printf::ArgType &AT =
4051      (CS.getKind() == ConversionSpecifier::FreeBSDbArg) ?
4052        ArgType(S.Context.IntTy) : ArgType::CPointerTy;
4053    if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType()))
4054      EmitFormatDiagnostic(
4055        S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
4056        << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
4057        << false << Ex->getSourceRange(),
4058        Ex->getLocStart(), /*IsStringLocation*/false,
4059        getSpecifierRange(startSpecifier, specifierLen));
4060
4061    // Type check the second argument (char * for both %b and %D)
4062    Ex = getDataArg(argIndex + 1);
4063    const analyze_printf::ArgType &AT2 = ArgType::CStrTy;
4064    if (AT2.isValid() && !AT2.matchesType(S.Context, Ex->getType()))
4065      EmitFormatDiagnostic(
4066        S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
4067        << AT2.getRepresentativeTypeName(S.Context) << Ex->getType()
4068        << false << Ex->getSourceRange(),
4069        Ex->getLocStart(), /*IsStringLocation*/false,
4070        getSpecifierRange(startSpecifier, specifierLen));
4071
4072     return true;
4073  }
4074
4075  // Check for using an Objective-C specific conversion specifier
4076  // in a non-ObjC literal.
4077  if (!ObjCContext && CS.isObjCArg()) {
4078    return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
4079                                                  specifierLen);
4080  }
4081
4082  // Check for invalid use of field width
4083  if (!FS.hasValidFieldWidth()) {
4084    HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
4085        startSpecifier, specifierLen);
4086  }
4087
4088  // Check for invalid use of precision
4089  if (!FS.hasValidPrecision()) {
4090    HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
4091        startSpecifier, specifierLen);
4092  }
4093
4094  // Check each flag does not conflict with any other component.
4095  if (!FS.hasValidThousandsGroupingPrefix())
4096    HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
4097  if (!FS.hasValidLeadingZeros())
4098    HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
4099  if (!FS.hasValidPlusPrefix())
4100    HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
4101  if (!FS.hasValidSpacePrefix())
4102    HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
4103  if (!FS.hasValidAlternativeForm())
4104    HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
4105  if (!FS.hasValidLeftJustified())
4106    HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
4107
4108  // Check that flags are not ignored by another flag
4109  if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
4110    HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
4111        startSpecifier, specifierLen);
4112  if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
4113    HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
4114            startSpecifier, specifierLen);
4115
4116  // Check the length modifier is valid with the given conversion specifier.
4117  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
4118    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
4119                                diag::warn_format_nonsensical_length);
4120  else if (!FS.hasStandardLengthModifier())
4121    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
4122  else if (!FS.hasStandardLengthConversionCombination())
4123    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
4124                                diag::warn_format_non_standard_conversion_spec);
4125
4126  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
4127    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
4128
4129  // The remaining checks depend on the data arguments.
4130  if (HasVAListArg)
4131    return true;
4132
4133  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
4134    return false;
4135
4136  const Expr *Arg = getDataArg(argIndex);
4137  if (!Arg)
4138    return true;
4139
4140  return checkFormatExpr(FS, startSpecifier, specifierLen, Arg);
4141}
4142
4143static bool requiresParensToAddCast(const Expr *E) {
4144  // FIXME: We should have a general way to reason about operator
4145  // precedence and whether parens are actually needed here.
4146  // Take care of a few common cases where they aren't.
4147  const Expr *Inside = E->IgnoreImpCasts();
4148  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside))
4149    Inside = POE->getSyntacticForm()->IgnoreImpCasts();
4150
4151  switch (Inside->getStmtClass()) {
4152  case Stmt::ArraySubscriptExprClass:
4153  case Stmt::CallExprClass:
4154  case Stmt::CharacterLiteralClass:
4155  case Stmt::CXXBoolLiteralExprClass:
4156  case Stmt::DeclRefExprClass:
4157  case Stmt::FloatingLiteralClass:
4158  case Stmt::IntegerLiteralClass:
4159  case Stmt::MemberExprClass:
4160  case Stmt::ObjCArrayLiteralClass:
4161  case Stmt::ObjCBoolLiteralExprClass:
4162  case Stmt::ObjCBoxedExprClass:
4163  case Stmt::ObjCDictionaryLiteralClass:
4164  case Stmt::ObjCEncodeExprClass:
4165  case Stmt::ObjCIvarRefExprClass:
4166  case Stmt::ObjCMessageExprClass:
4167  case Stmt::ObjCPropertyRefExprClass:
4168  case Stmt::ObjCStringLiteralClass:
4169  case Stmt::ObjCSubscriptRefExprClass:
4170  case Stmt::ParenExprClass:
4171  case Stmt::StringLiteralClass:
4172  case Stmt::UnaryOperatorClass:
4173    return false;
4174  default:
4175    return true;
4176  }
4177}
4178
4179static std::pair<QualType, StringRef>
4180shouldNotPrintDirectly(const ASTContext &Context,
4181                       QualType IntendedTy,
4182                       const Expr *E) {
4183  // Use a 'while' to peel off layers of typedefs.
4184  QualType TyTy = IntendedTy;
4185  while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) {
4186    StringRef Name = UserTy->getDecl()->getName();
4187    QualType CastTy = llvm::StringSwitch<QualType>(Name)
4188      .Case("NSInteger", Context.LongTy)
4189      .Case("NSUInteger", Context.UnsignedLongTy)
4190      .Case("SInt32", Context.IntTy)
4191      .Case("UInt32", Context.UnsignedIntTy)
4192      .Default(QualType());
4193
4194    if (!CastTy.isNull())
4195      return std::make_pair(CastTy, Name);
4196
4197    TyTy = UserTy->desugar();
4198  }
4199
4200  // Strip parens if necessary.
4201  if (const ParenExpr *PE = dyn_cast<ParenExpr>(E))
4202    return shouldNotPrintDirectly(Context,
4203                                  PE->getSubExpr()->getType(),
4204                                  PE->getSubExpr());
4205
4206  // If this is a conditional expression, then its result type is constructed
4207  // via usual arithmetic conversions and thus there might be no necessary
4208  // typedef sugar there.  Recurse to operands to check for NSInteger &
4209  // Co. usage condition.
4210  if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
4211    QualType TrueTy, FalseTy;
4212    StringRef TrueName, FalseName;
4213
4214    std::tie(TrueTy, TrueName) =
4215      shouldNotPrintDirectly(Context,
4216                             CO->getTrueExpr()->getType(),
4217                             CO->getTrueExpr());
4218    std::tie(FalseTy, FalseName) =
4219      shouldNotPrintDirectly(Context,
4220                             CO->getFalseExpr()->getType(),
4221                             CO->getFalseExpr());
4222
4223    if (TrueTy == FalseTy)
4224      return std::make_pair(TrueTy, TrueName);
4225    else if (TrueTy.isNull())
4226      return std::make_pair(FalseTy, FalseName);
4227    else if (FalseTy.isNull())
4228      return std::make_pair(TrueTy, TrueName);
4229  }
4230
4231  return std::make_pair(QualType(), StringRef());
4232}
4233
4234bool
4235CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
4236                                    const char *StartSpecifier,
4237                                    unsigned SpecifierLen,
4238                                    const Expr *E) {
4239  using namespace analyze_format_string;
4240  using namespace analyze_printf;
4241  // Now type check the data expression that matches the
4242  // format specifier.
4243  const analyze_printf::ArgType &AT = FS.getArgType(S.Context,
4244                                                    ObjCContext);
4245  if (!AT.isValid())
4246    return true;
4247
4248  QualType ExprTy = E->getType();
4249  while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) {
4250    ExprTy = TET->getUnderlyingExpr()->getType();
4251  }
4252
4253  analyze_printf::ArgType::MatchKind match = AT.matchesType(S.Context, ExprTy);
4254
4255  if (match == analyze_printf::ArgType::Match) {
4256    return true;
4257  }
4258
4259  // Look through argument promotions for our error message's reported type.
4260  // This includes the integral and floating promotions, but excludes array
4261  // and function pointer decay; seeing that an argument intended to be a
4262  // string has type 'char [6]' is probably more confusing than 'char *'.
4263  if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
4264    if (ICE->getCastKind() == CK_IntegralCast ||
4265        ICE->getCastKind() == CK_FloatingCast) {
4266      E = ICE->getSubExpr();
4267      ExprTy = E->getType();
4268
4269      // Check if we didn't match because of an implicit cast from a 'char'
4270      // or 'short' to an 'int'.  This is done because printf is a varargs
4271      // function.
4272      if (ICE->getType() == S.Context.IntTy ||
4273          ICE->getType() == S.Context.UnsignedIntTy) {
4274        // All further checking is done on the subexpression.
4275        if (AT.matchesType(S.Context, ExprTy))
4276          return true;
4277      }
4278    }
4279  } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) {
4280    // Special case for 'a', which has type 'int' in C.
4281    // Note, however, that we do /not/ want to treat multibyte constants like
4282    // 'MooV' as characters! This form is deprecated but still exists.
4283    if (ExprTy == S.Context.IntTy)
4284      if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue()))
4285        ExprTy = S.Context.CharTy;
4286  }
4287
4288  // Look through enums to their underlying type.
4289  bool IsEnum = false;
4290  if (auto EnumTy = ExprTy->getAs<EnumType>()) {
4291    ExprTy = EnumTy->getDecl()->getIntegerType();
4292    IsEnum = true;
4293  }
4294
4295  // %C in an Objective-C context prints a unichar, not a wchar_t.
4296  // If the argument is an integer of some kind, believe the %C and suggest
4297  // a cast instead of changing the conversion specifier.
4298  QualType IntendedTy = ExprTy;
4299  if (ObjCContext &&
4300      FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) {
4301    if (ExprTy->isIntegralOrUnscopedEnumerationType() &&
4302        !ExprTy->isCharType()) {
4303      // 'unichar' is defined as a typedef of unsigned short, but we should
4304      // prefer using the typedef if it is visible.
4305      IntendedTy = S.Context.UnsignedShortTy;
4306
4307      // While we are here, check if the value is an IntegerLiteral that happens
4308      // to be within the valid range.
4309      if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) {
4310        const llvm::APInt &V = IL->getValue();
4311        if (V.getActiveBits() <= S.Context.getTypeSize(IntendedTy))
4312          return true;
4313      }
4314
4315      LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(),
4316                          Sema::LookupOrdinaryName);
4317      if (S.LookupName(Result, S.getCurScope())) {
4318        NamedDecl *ND = Result.getFoundDecl();
4319        if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND))
4320          if (TD->getUnderlyingType() == IntendedTy)
4321            IntendedTy = S.Context.getTypedefType(TD);
4322      }
4323    }
4324  }
4325
4326  // Special-case some of Darwin's platform-independence types by suggesting
4327  // casts to primitive types that are known to be large enough.
4328  bool ShouldNotPrintDirectly = false; StringRef CastTyName;
4329  if (S.Context.getTargetInfo().getTriple().isOSDarwin()) {
4330    QualType CastTy;
4331    std::tie(CastTy, CastTyName) = shouldNotPrintDirectly(S.Context, IntendedTy, E);
4332    if (!CastTy.isNull()) {
4333      IntendedTy = CastTy;
4334      ShouldNotPrintDirectly = true;
4335    }
4336  }
4337
4338  // We may be able to offer a FixItHint if it is a supported type.
4339  PrintfSpecifier fixedFS = FS;
4340  bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(),
4341                                 S.Context, ObjCContext);
4342
4343  if (success) {
4344    // Get the fix string from the fixed format specifier
4345    SmallString<16> buf;
4346    llvm::raw_svector_ostream os(buf);
4347    fixedFS.toString(os);
4348
4349    CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen);
4350
4351    if (IntendedTy == ExprTy && !ShouldNotPrintDirectly) {
4352      unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
4353      if (match == analyze_format_string::ArgType::NoMatchPedantic) {
4354        diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
4355      }
4356      // In this case, the specifier is wrong and should be changed to match
4357      // the argument.
4358      EmitFormatDiagnostic(S.PDiag(diag)
4359                               << AT.getRepresentativeTypeName(S.Context)
4360                               << IntendedTy << IsEnum << E->getSourceRange(),
4361                           E->getLocStart(),
4362                           /*IsStringLocation*/ false, SpecRange,
4363                           FixItHint::CreateReplacement(SpecRange, os.str()));
4364
4365    } else {
4366      // The canonical type for formatting this value is different from the
4367      // actual type of the expression. (This occurs, for example, with Darwin's
4368      // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but
4369      // should be printed as 'long' for 64-bit compatibility.)
4370      // Rather than emitting a normal format/argument mismatch, we want to
4371      // add a cast to the recommended type (and correct the format string
4372      // if necessary).
4373      SmallString<16> CastBuf;
4374      llvm::raw_svector_ostream CastFix(CastBuf);
4375      CastFix << "(";
4376      IntendedTy.print(CastFix, S.Context.getPrintingPolicy());
4377      CastFix << ")";
4378
4379      SmallVector<FixItHint,4> Hints;
4380      if (!AT.matchesType(S.Context, IntendedTy))
4381        Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str()));
4382
4383      if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) {
4384        // If there's already a cast present, just replace it.
4385        SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc());
4386        Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str()));
4387
4388      } else if (!requiresParensToAddCast(E)) {
4389        // If the expression has high enough precedence,
4390        // just write the C-style cast.
4391        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
4392                                                   CastFix.str()));
4393      } else {
4394        // Otherwise, add parens around the expression as well as the cast.
4395        CastFix << "(";
4396        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
4397                                                   CastFix.str()));
4398
4399        SourceLocation After = S.getLocForEndOfToken(E->getLocEnd());
4400        Hints.push_back(FixItHint::CreateInsertion(After, ")"));
4401      }
4402
4403      if (ShouldNotPrintDirectly) {
4404        // The expression has a type that should not be printed directly.
4405        // We extract the name from the typedef because we don't want to show
4406        // the underlying type in the diagnostic.
4407        StringRef Name;
4408        if (const TypedefType *TypedefTy = dyn_cast<TypedefType>(ExprTy))
4409          Name = TypedefTy->getDecl()->getName();
4410        else
4411          Name = CastTyName;
4412        EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast)
4413                               << Name << IntendedTy << IsEnum
4414                               << E->getSourceRange(),
4415                             E->getLocStart(), /*IsStringLocation=*/false,
4416                             SpecRange, Hints);
4417      } else {
4418        // In this case, the expression could be printed using a different
4419        // specifier, but we've decided that the specifier is probably correct
4420        // and we should cast instead. Just use the normal warning message.
4421        EmitFormatDiagnostic(
4422          S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
4423            << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum
4424            << E->getSourceRange(),
4425          E->getLocStart(), /*IsStringLocation*/false,
4426          SpecRange, Hints);
4427      }
4428    }
4429  } else {
4430    const CharSourceRange &CSR = getSpecifierRange(StartSpecifier,
4431                                                   SpecifierLen);
4432    // Since the warning for passing non-POD types to variadic functions
4433    // was deferred until now, we emit a warning for non-POD
4434    // arguments here.
4435    switch (S.isValidVarArgType(ExprTy)) {
4436    case Sema::VAK_Valid:
4437    case Sema::VAK_ValidInCXX11: {
4438      unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
4439      if (match == analyze_printf::ArgType::NoMatchPedantic) {
4440        diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
4441      }
4442
4443      EmitFormatDiagnostic(
4444          S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context) << ExprTy
4445                        << IsEnum << CSR << E->getSourceRange(),
4446          E->getLocStart(), /*IsStringLocation*/ false, CSR);
4447      break;
4448    }
4449    case Sema::VAK_Undefined:
4450    case Sema::VAK_MSVCUndefined:
4451      EmitFormatDiagnostic(
4452        S.PDiag(diag::warn_non_pod_vararg_with_format_string)
4453          << S.getLangOpts().CPlusPlus11
4454          << ExprTy
4455          << CallType
4456          << AT.getRepresentativeTypeName(S.Context)
4457          << CSR
4458          << E->getSourceRange(),
4459        E->getLocStart(), /*IsStringLocation*/false, CSR);
4460      checkForCStrMembers(AT, E);
4461      break;
4462
4463    case Sema::VAK_Invalid:
4464      if (ExprTy->isObjCObjectType())
4465        EmitFormatDiagnostic(
4466          S.PDiag(diag::err_cannot_pass_objc_interface_to_vararg_format)
4467            << S.getLangOpts().CPlusPlus11
4468            << ExprTy
4469            << CallType
4470            << AT.getRepresentativeTypeName(S.Context)
4471            << CSR
4472            << E->getSourceRange(),
4473          E->getLocStart(), /*IsStringLocation*/false, CSR);
4474      else
4475        // FIXME: If this is an initializer list, suggest removing the braces
4476        // or inserting a cast to the target type.
4477        S.Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg_format)
4478          << isa<InitListExpr>(E) << ExprTy << CallType
4479          << AT.getRepresentativeTypeName(S.Context)
4480          << E->getSourceRange();
4481      break;
4482    }
4483
4484    assert(FirstDataArg + FS.getArgIndex() < CheckedVarArgs.size() &&
4485           "format string specifier index out of range");
4486    CheckedVarArgs[FirstDataArg + FS.getArgIndex()] = true;
4487  }
4488
4489  return true;
4490}
4491
4492//===--- CHECK: Scanf format string checking ------------------------------===//
4493
4494namespace {
4495class CheckScanfHandler : public CheckFormatHandler {
4496public:
4497  CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
4498                    const Expr *origFormatExpr, unsigned firstDataArg,
4499                    unsigned numDataArgs, const char *beg, bool hasVAListArg,
4500                    ArrayRef<const Expr *> Args,
4501                    unsigned formatIdx, bool inFunctionCall,
4502                    Sema::VariadicCallType CallType,
4503                    llvm::SmallBitVector &CheckedVarArgs)
4504    : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
4505                         numDataArgs, beg, hasVAListArg,
4506                         Args, formatIdx, inFunctionCall, CallType,
4507                         CheckedVarArgs)
4508  {}
4509
4510  bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
4511                            const char *startSpecifier,
4512                            unsigned specifierLen) override;
4513
4514  bool HandleInvalidScanfConversionSpecifier(
4515          const analyze_scanf::ScanfSpecifier &FS,
4516          const char *startSpecifier,
4517          unsigned specifierLen) override;
4518
4519  void HandleIncompleteScanList(const char *start, const char *end) override;
4520};
4521}
4522
4523void CheckScanfHandler::HandleIncompleteScanList(const char *start,
4524                                                 const char *end) {
4525  EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
4526                       getLocationOfByte(end), /*IsStringLocation*/true,
4527                       getSpecifierRange(start, end - start));
4528}
4529
4530bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
4531                                        const analyze_scanf::ScanfSpecifier &FS,
4532                                        const char *startSpecifier,
4533                                        unsigned specifierLen) {
4534
4535  const analyze_scanf::ScanfConversionSpecifier &CS =
4536    FS.getConversionSpecifier();
4537
4538  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
4539                                          getLocationOfByte(CS.getStart()),
4540                                          startSpecifier, specifierLen,
4541                                          CS.getStart(), CS.getLength());
4542}
4543
4544bool CheckScanfHandler::HandleScanfSpecifier(
4545                                       const analyze_scanf::ScanfSpecifier &FS,
4546                                       const char *startSpecifier,
4547                                       unsigned specifierLen) {
4548
4549  using namespace analyze_scanf;
4550  using namespace analyze_format_string;
4551
4552  const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
4553
4554  // Handle case where '%' and '*' don't consume an argument.  These shouldn't
4555  // be used to decide if we are using positional arguments consistently.
4556  if (FS.consumesDataArgument()) {
4557    if (atFirstArg) {
4558      atFirstArg = false;
4559      usesPositionalArgs = FS.usesPositionalArg();
4560    }
4561    else if (usesPositionalArgs != FS.usesPositionalArg()) {
4562      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
4563                                        startSpecifier, specifierLen);
4564      return false;
4565    }
4566  }
4567
4568  // Check if the field with is non-zero.
4569  const OptionalAmount &Amt = FS.getFieldWidth();
4570  if (Amt.getHowSpecified() == OptionalAmount::Constant) {
4571    if (Amt.getConstantAmount() == 0) {
4572      const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
4573                                                   Amt.getConstantLength());
4574      EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
4575                           getLocationOfByte(Amt.getStart()),
4576                           /*IsStringLocation*/true, R,
4577                           FixItHint::CreateRemoval(R));
4578    }
4579  }
4580
4581  if (!FS.consumesDataArgument()) {
4582    // FIXME: Technically specifying a precision or field width here
4583    // makes no sense.  Worth issuing a warning at some point.
4584    return true;
4585  }
4586
4587  // Consume the argument.
4588  unsigned argIndex = FS.getArgIndex();
4589  if (argIndex < NumDataArgs) {
4590      // The check to see if the argIndex is valid will come later.
4591      // We set the bit here because we may exit early from this
4592      // function if we encounter some other error.
4593    CoveredArgs.set(argIndex);
4594  }
4595
4596  // Check the length modifier is valid with the given conversion specifier.
4597  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
4598    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
4599                                diag::warn_format_nonsensical_length);
4600  else if (!FS.hasStandardLengthModifier())
4601    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
4602  else if (!FS.hasStandardLengthConversionCombination())
4603    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
4604                                diag::warn_format_non_standard_conversion_spec);
4605
4606  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
4607    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
4608
4609  // The remaining checks depend on the data arguments.
4610  if (HasVAListArg)
4611    return true;
4612
4613  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
4614    return false;
4615
4616  // Check that the argument type matches the format specifier.
4617  const Expr *Ex = getDataArg(argIndex);
4618  if (!Ex)
4619    return true;
4620
4621  const analyze_format_string::ArgType &AT = FS.getArgType(S.Context);
4622
4623  if (!AT.isValid()) {
4624    return true;
4625  }
4626
4627  analyze_format_string::ArgType::MatchKind match =
4628      AT.matchesType(S.Context, Ex->getType());
4629  if (match == analyze_format_string::ArgType::Match) {
4630    return true;
4631  }
4632
4633  ScanfSpecifier fixedFS = FS;
4634  bool success = fixedFS.fixType(Ex->getType(), Ex->IgnoreImpCasts()->getType(),
4635                                 S.getLangOpts(), S.Context);
4636
4637  unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
4638  if (match == analyze_format_string::ArgType::NoMatchPedantic) {
4639    diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
4640  }
4641
4642  if (success) {
4643    // Get the fix string from the fixed format specifier.
4644    SmallString<128> buf;
4645    llvm::raw_svector_ostream os(buf);
4646    fixedFS.toString(os);
4647
4648    EmitFormatDiagnostic(
4649        S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context)
4650                      << Ex->getType() << false << Ex->getSourceRange(),
4651        Ex->getLocStart(),
4652        /*IsStringLocation*/ false,
4653        getSpecifierRange(startSpecifier, specifierLen),
4654        FixItHint::CreateReplacement(
4655            getSpecifierRange(startSpecifier, specifierLen), os.str()));
4656  } else {
4657    EmitFormatDiagnostic(S.PDiag(diag)
4658                             << AT.getRepresentativeTypeName(S.Context)
4659                             << Ex->getType() << false << Ex->getSourceRange(),
4660                         Ex->getLocStart(),
4661                         /*IsStringLocation*/ false,
4662                         getSpecifierRange(startSpecifier, specifierLen));
4663  }
4664
4665  return true;
4666}
4667
4668void Sema::CheckFormatString(const StringLiteral *FExpr,
4669                             const Expr *OrigFormatExpr,
4670                             ArrayRef<const Expr *> Args,
4671                             bool HasVAListArg, unsigned format_idx,
4672                             unsigned firstDataArg, FormatStringType Type,
4673                             bool inFunctionCall, VariadicCallType CallType,
4674                             llvm::SmallBitVector &CheckedVarArgs) {
4675
4676  // CHECK: is the format string a wide literal?
4677  if (!FExpr->isAscii() && !FExpr->isUTF8()) {
4678    CheckFormatHandler::EmitFormatDiagnostic(
4679      *this, inFunctionCall, Args[format_idx],
4680      PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
4681      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
4682    return;
4683  }
4684
4685  // Str - The format string.  NOTE: this is NOT null-terminated!
4686  StringRef StrRef = FExpr->getString();
4687  const char *Str = StrRef.data();
4688  // Account for cases where the string literal is truncated in a declaration.
4689  const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType());
4690  assert(T && "String literal not of constant array type!");
4691  size_t TypeSize = T->getSize().getZExtValue();
4692  size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size());
4693  const unsigned numDataArgs = Args.size() - firstDataArg;
4694
4695  // Emit a warning if the string literal is truncated and does not contain an
4696  // embedded null character.
4697  if (TypeSize <= StrRef.size() &&
4698      StrRef.substr(0, TypeSize).find('\0') == StringRef::npos) {
4699    CheckFormatHandler::EmitFormatDiagnostic(
4700        *this, inFunctionCall, Args[format_idx],
4701        PDiag(diag::warn_printf_format_string_not_null_terminated),
4702        FExpr->getLocStart(),
4703        /*IsStringLocation=*/true, OrigFormatExpr->getSourceRange());
4704    return;
4705  }
4706
4707  // CHECK: empty format string?
4708  if (StrLen == 0 && numDataArgs > 0) {
4709    CheckFormatHandler::EmitFormatDiagnostic(
4710      *this, inFunctionCall, Args[format_idx],
4711      PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
4712      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
4713    return;
4714  }
4715
4716  if (Type == FST_Printf || Type == FST_NSString ||
4717      Type == FST_FreeBSDKPrintf || Type == FST_OSTrace) {
4718    CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
4719                         numDataArgs, (Type == FST_NSString || Type == FST_OSTrace),
4720                         Str, HasVAListArg, Args, format_idx,
4721                         inFunctionCall, CallType, CheckedVarArgs);
4722
4723    if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
4724                                                  getLangOpts(),
4725                                                  Context.getTargetInfo(),
4726                                                  Type == FST_FreeBSDKPrintf))
4727      H.DoneProcessing();
4728  } else if (Type == FST_Scanf) {
4729    CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs,
4730                        Str, HasVAListArg, Args, format_idx,
4731                        inFunctionCall, CallType, CheckedVarArgs);
4732
4733    if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
4734                                                 getLangOpts(),
4735                                                 Context.getTargetInfo()))
4736      H.DoneProcessing();
4737  } // TODO: handle other formats
4738}
4739
4740bool Sema::FormatStringHasSArg(const StringLiteral *FExpr) {
4741  // Str - The format string.  NOTE: this is NOT null-terminated!
4742  StringRef StrRef = FExpr->getString();
4743  const char *Str = StrRef.data();
4744  // Account for cases where the string literal is truncated in a declaration.
4745  const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType());
4746  assert(T && "String literal not of constant array type!");
4747  size_t TypeSize = T->getSize().getZExtValue();
4748  size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size());
4749  return analyze_format_string::ParseFormatStringHasSArg(Str, Str + StrLen,
4750                                                         getLangOpts(),
4751                                                         Context.getTargetInfo());
4752}
4753
4754//===--- CHECK: Warn on use of wrong absolute value function. -------------===//
4755
4756// Returns the related absolute value function that is larger, of 0 if one
4757// does not exist.
4758static unsigned getLargerAbsoluteValueFunction(unsigned AbsFunction) {
4759  switch (AbsFunction) {
4760  default:
4761    return 0;
4762
4763  case Builtin::BI__builtin_abs:
4764    return Builtin::BI__builtin_labs;
4765  case Builtin::BI__builtin_labs:
4766    return Builtin::BI__builtin_llabs;
4767  case Builtin::BI__builtin_llabs:
4768    return 0;
4769
4770  case Builtin::BI__builtin_fabsf:
4771    return Builtin::BI__builtin_fabs;
4772  case Builtin::BI__builtin_fabs:
4773    return Builtin::BI__builtin_fabsl;
4774  case Builtin::BI__builtin_fabsl:
4775    return 0;
4776
4777  case Builtin::BI__builtin_cabsf:
4778    return Builtin::BI__builtin_cabs;
4779  case Builtin::BI__builtin_cabs:
4780    return Builtin::BI__builtin_cabsl;
4781  case Builtin::BI__builtin_cabsl:
4782    return 0;
4783
4784  case Builtin::BIabs:
4785    return Builtin::BIlabs;
4786  case Builtin::BIlabs:
4787    return Builtin::BIllabs;
4788  case Builtin::BIllabs:
4789    return 0;
4790
4791  case Builtin::BIfabsf:
4792    return Builtin::BIfabs;
4793  case Builtin::BIfabs:
4794    return Builtin::BIfabsl;
4795  case Builtin::BIfabsl:
4796    return 0;
4797
4798  case Builtin::BIcabsf:
4799   return Builtin::BIcabs;
4800  case Builtin::BIcabs:
4801    return Builtin::BIcabsl;
4802  case Builtin::BIcabsl:
4803    return 0;
4804  }
4805}
4806
4807// Returns the argument type of the absolute value function.
4808static QualType getAbsoluteValueArgumentType(ASTContext &Context,
4809                                             unsigned AbsType) {
4810  if (AbsType == 0)
4811    return QualType();
4812
4813  ASTContext::GetBuiltinTypeError Error = ASTContext::GE_None;
4814  QualType BuiltinType = Context.GetBuiltinType(AbsType, Error);
4815  if (Error != ASTContext::GE_None)
4816    return QualType();
4817
4818  const FunctionProtoType *FT = BuiltinType->getAs<FunctionProtoType>();
4819  if (!FT)
4820    return QualType();
4821
4822  if (FT->getNumParams() != 1)
4823    return QualType();
4824
4825  return FT->getParamType(0);
4826}
4827
4828// Returns the best absolute value function, or zero, based on type and
4829// current absolute value function.
4830static unsigned getBestAbsFunction(ASTContext &Context, QualType ArgType,
4831                                   unsigned AbsFunctionKind) {
4832  unsigned BestKind = 0;
4833  uint64_t ArgSize = Context.getTypeSize(ArgType);
4834  for (unsigned Kind = AbsFunctionKind; Kind != 0;
4835       Kind = getLargerAbsoluteValueFunction(Kind)) {
4836    QualType ParamType = getAbsoluteValueArgumentType(Context, Kind);
4837    if (Context.getTypeSize(ParamType) >= ArgSize) {
4838      if (BestKind == 0)
4839        BestKind = Kind;
4840      else if (Context.hasSameType(ParamType, ArgType)) {
4841        BestKind = Kind;
4842        break;
4843      }
4844    }
4845  }
4846  return BestKind;
4847}
4848
4849enum AbsoluteValueKind {
4850  AVK_Integer,
4851  AVK_Floating,
4852  AVK_Complex
4853};
4854
4855static AbsoluteValueKind getAbsoluteValueKind(QualType T) {
4856  if (T->isIntegralOrEnumerationType())
4857    return AVK_Integer;
4858  if (T->isRealFloatingType())
4859    return AVK_Floating;
4860  if (T->isAnyComplexType())
4861    return AVK_Complex;
4862
4863  llvm_unreachable("Type not integer, floating, or complex");
4864}
4865
4866// Changes the absolute value function to a different type.  Preserves whether
4867// the function is a builtin.
4868static unsigned changeAbsFunction(unsigned AbsKind,
4869                                  AbsoluteValueKind ValueKind) {
4870  switch (ValueKind) {
4871  case AVK_Integer:
4872    switch (AbsKind) {
4873    default:
4874      return 0;
4875    case Builtin::BI__builtin_fabsf:
4876    case Builtin::BI__builtin_fabs:
4877    case Builtin::BI__builtin_fabsl:
4878    case Builtin::BI__builtin_cabsf:
4879    case Builtin::BI__builtin_cabs:
4880    case Builtin::BI__builtin_cabsl:
4881      return Builtin::BI__builtin_abs;
4882    case Builtin::BIfabsf:
4883    case Builtin::BIfabs:
4884    case Builtin::BIfabsl:
4885    case Builtin::BIcabsf:
4886    case Builtin::BIcabs:
4887    case Builtin::BIcabsl:
4888      return Builtin::BIabs;
4889    }
4890  case AVK_Floating:
4891    switch (AbsKind) {
4892    default:
4893      return 0;
4894    case Builtin::BI__builtin_abs:
4895    case Builtin::BI__builtin_labs:
4896    case Builtin::BI__builtin_llabs:
4897    case Builtin::BI__builtin_cabsf:
4898    case Builtin::BI__builtin_cabs:
4899    case Builtin::BI__builtin_cabsl:
4900      return Builtin::BI__builtin_fabsf;
4901    case Builtin::BIabs:
4902    case Builtin::BIlabs:
4903    case Builtin::BIllabs:
4904    case Builtin::BIcabsf:
4905    case Builtin::BIcabs:
4906    case Builtin::BIcabsl:
4907      return Builtin::BIfabsf;
4908    }
4909  case AVK_Complex:
4910    switch (AbsKind) {
4911    default:
4912      return 0;
4913    case Builtin::BI__builtin_abs:
4914    case Builtin::BI__builtin_labs:
4915    case Builtin::BI__builtin_llabs:
4916    case Builtin::BI__builtin_fabsf:
4917    case Builtin::BI__builtin_fabs:
4918    case Builtin::BI__builtin_fabsl:
4919      return Builtin::BI__builtin_cabsf;
4920    case Builtin::BIabs:
4921    case Builtin::BIlabs:
4922    case Builtin::BIllabs:
4923    case Builtin::BIfabsf:
4924    case Builtin::BIfabs:
4925    case Builtin::BIfabsl:
4926      return Builtin::BIcabsf;
4927    }
4928  }
4929  llvm_unreachable("Unable to convert function");
4930}
4931
4932static unsigned getAbsoluteValueFunctionKind(const FunctionDecl *FDecl) {
4933  const IdentifierInfo *FnInfo = FDecl->getIdentifier();
4934  if (!FnInfo)
4935    return 0;
4936
4937  switch (FDecl->getBuiltinID()) {
4938  default:
4939    return 0;
4940  case Builtin::BI__builtin_abs:
4941  case Builtin::BI__builtin_fabs:
4942  case Builtin::BI__builtin_fabsf:
4943  case Builtin::BI__builtin_fabsl:
4944  case Builtin::BI__builtin_labs:
4945  case Builtin::BI__builtin_llabs:
4946  case Builtin::BI__builtin_cabs:
4947  case Builtin::BI__builtin_cabsf:
4948  case Builtin::BI__builtin_cabsl:
4949  case Builtin::BIabs:
4950  case Builtin::BIlabs:
4951  case Builtin::BIllabs:
4952  case Builtin::BIfabs:
4953  case Builtin::BIfabsf:
4954  case Builtin::BIfabsl:
4955  case Builtin::BIcabs:
4956  case Builtin::BIcabsf:
4957  case Builtin::BIcabsl:
4958    return FDecl->getBuiltinID();
4959  }
4960  llvm_unreachable("Unknown Builtin type");
4961}
4962
4963// If the replacement is valid, emit a note with replacement function.
4964// Additionally, suggest including the proper header if not already included.
4965static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range,
4966                            unsigned AbsKind, QualType ArgType) {
4967  bool EmitHeaderHint = true;
4968  const char *HeaderName = nullptr;
4969  const char *FunctionName = nullptr;
4970  if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) {
4971    FunctionName = "std::abs";
4972    if (ArgType->isIntegralOrEnumerationType()) {
4973      HeaderName = "cstdlib";
4974    } else if (ArgType->isRealFloatingType()) {
4975      HeaderName = "cmath";
4976    } else {
4977      llvm_unreachable("Invalid Type");
4978    }
4979
4980    // Lookup all std::abs
4981    if (NamespaceDecl *Std = S.getStdNamespace()) {
4982      LookupResult R(S, &S.Context.Idents.get("abs"), Loc, Sema::LookupAnyName);
4983      R.suppressDiagnostics();
4984      S.LookupQualifiedName(R, Std);
4985
4986      for (const auto *I : R) {
4987        const FunctionDecl *FDecl = nullptr;
4988        if (const UsingShadowDecl *UsingD = dyn_cast<UsingShadowDecl>(I)) {
4989          FDecl = dyn_cast<FunctionDecl>(UsingD->getTargetDecl());
4990        } else {
4991          FDecl = dyn_cast<FunctionDecl>(I);
4992        }
4993        if (!FDecl)
4994          continue;
4995
4996        // Found std::abs(), check that they are the right ones.
4997        if (FDecl->getNumParams() != 1)
4998          continue;
4999
5000        // Check that the parameter type can handle the argument.
5001        QualType ParamType = FDecl->getParamDecl(0)->getType();
5002        if (getAbsoluteValueKind(ArgType) == getAbsoluteValueKind(ParamType) &&
5003            S.Context.getTypeSize(ArgType) <=
5004                S.Context.getTypeSize(ParamType)) {
5005          // Found a function, don't need the header hint.
5006          EmitHeaderHint = false;
5007          break;
5008        }
5009      }
5010    }
5011  } else {
5012    FunctionName = S.Context.BuiltinInfo.getName(AbsKind);
5013    HeaderName = S.Context.BuiltinInfo.getHeaderName(AbsKind);
5014
5015    if (HeaderName) {
5016      DeclarationName DN(&S.Context.Idents.get(FunctionName));
5017      LookupResult R(S, DN, Loc, Sema::LookupAnyName);
5018      R.suppressDiagnostics();
5019      S.LookupName(R, S.getCurScope());
5020
5021      if (R.isSingleResult()) {
5022        FunctionDecl *FD = dyn_cast<FunctionDecl>(R.getFoundDecl());
5023        if (FD && FD->getBuiltinID() == AbsKind) {
5024          EmitHeaderHint = false;
5025        } else {
5026          return;
5027        }
5028      } else if (!R.empty()) {
5029        return;
5030      }
5031    }
5032  }
5033
5034  S.Diag(Loc, diag::note_replace_abs_function)
5035      << FunctionName << FixItHint::CreateReplacement(Range, FunctionName);
5036
5037  if (!HeaderName)
5038    return;
5039
5040  if (!EmitHeaderHint)
5041    return;
5042
5043  S.Diag(Loc, diag::note_include_header_or_declare) << HeaderName
5044                                                    << FunctionName;
5045}
5046
5047static bool IsFunctionStdAbs(const FunctionDecl *FDecl) {
5048  if (!FDecl)
5049    return false;
5050
5051  if (!FDecl->getIdentifier() || !FDecl->getIdentifier()->isStr("abs"))
5052    return false;
5053
5054  const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(FDecl->getDeclContext());
5055
5056  while (ND && ND->isInlineNamespace()) {
5057    ND = dyn_cast<NamespaceDecl>(ND->getDeclContext());
5058  }
5059
5060  if (!ND || !ND->getIdentifier() || !ND->getIdentifier()->isStr("std"))
5061    return false;
5062
5063  if (!isa<TranslationUnitDecl>(ND->getDeclContext()))
5064    return false;
5065
5066  return true;
5067}
5068
5069// Warn when using the wrong abs() function.
5070void Sema::CheckAbsoluteValueFunction(const CallExpr *Call,
5071                                      const FunctionDecl *FDecl,
5072                                      IdentifierInfo *FnInfo) {
5073  if (Call->getNumArgs() != 1)
5074    return;
5075
5076  unsigned AbsKind = getAbsoluteValueFunctionKind(FDecl);
5077  bool IsStdAbs = IsFunctionStdAbs(FDecl);
5078  if (AbsKind == 0 && !IsStdAbs)
5079    return;
5080
5081  QualType ArgType = Call->getArg(0)->IgnoreParenImpCasts()->getType();
5082  QualType ParamType = Call->getArg(0)->getType();
5083
5084  // Unsigned types cannot be negative.  Suggest removing the absolute value
5085  // function call.
5086  if (ArgType->isUnsignedIntegerType()) {
5087    const char *FunctionName =
5088        IsStdAbs ? "std::abs" : Context.BuiltinInfo.getName(AbsKind);
5089    Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType;
5090    Diag(Call->getExprLoc(), diag::note_remove_abs)
5091        << FunctionName
5092        << FixItHint::CreateRemoval(Call->getCallee()->getSourceRange());
5093    return;
5094  }
5095
5096  // Taking the absolute value of a pointer is very suspicious, they probably
5097  // wanted to index into an array, dereference a pointer, call a function, etc.
5098  if (ArgType->isPointerType() || ArgType->canDecayToPointerType()) {
5099    unsigned DiagType = 0;
5100    if (ArgType->isFunctionType())
5101      DiagType = 1;
5102    else if (ArgType->isArrayType())
5103      DiagType = 2;
5104
5105    Diag(Call->getExprLoc(), diag::warn_pointer_abs) << DiagType << ArgType;
5106    return;
5107  }
5108
5109  // std::abs has overloads which prevent most of the absolute value problems
5110  // from occurring.
5111  if (IsStdAbs)
5112    return;
5113
5114  AbsoluteValueKind ArgValueKind = getAbsoluteValueKind(ArgType);
5115  AbsoluteValueKind ParamValueKind = getAbsoluteValueKind(ParamType);
5116
5117  // The argument and parameter are the same kind.  Check if they are the right
5118  // size.
5119  if (ArgValueKind == ParamValueKind) {
5120    if (Context.getTypeSize(ArgType) <= Context.getTypeSize(ParamType))
5121      return;
5122
5123    unsigned NewAbsKind = getBestAbsFunction(Context, ArgType, AbsKind);
5124    Diag(Call->getExprLoc(), diag::warn_abs_too_small)
5125        << FDecl << ArgType << ParamType;
5126
5127    if (NewAbsKind == 0)
5128      return;
5129
5130    emitReplacement(*this, Call->getExprLoc(),
5131                    Call->getCallee()->getSourceRange(), NewAbsKind, ArgType);
5132    return;
5133  }
5134
5135  // ArgValueKind != ParamValueKind
5136  // The wrong type of absolute value function was used.  Attempt to find the
5137  // proper one.
5138  unsigned NewAbsKind = changeAbsFunction(AbsKind, ArgValueKind);
5139  NewAbsKind = getBestAbsFunction(Context, ArgType, NewAbsKind);
5140  if (NewAbsKind == 0)
5141    return;
5142
5143  Diag(Call->getExprLoc(), diag::warn_wrong_absolute_value_type)
5144      << FDecl << ParamValueKind << ArgValueKind;
5145
5146  emitReplacement(*this, Call->getExprLoc(),
5147                  Call->getCallee()->getSourceRange(), NewAbsKind, ArgType);
5148  return;
5149}
5150
5151//===--- CHECK: Standard memory functions ---------------------------------===//
5152
5153/// \brief Takes the expression passed to the size_t parameter of functions
5154/// such as memcmp, strncat, etc and warns if it's a comparison.
5155///
5156/// This is to catch typos like `if (memcmp(&a, &b, sizeof(a) > 0))`.
5157static bool CheckMemorySizeofForComparison(Sema &S, const Expr *E,
5158                                           IdentifierInfo *FnName,
5159                                           SourceLocation FnLoc,
5160                                           SourceLocation RParenLoc) {
5161  const BinaryOperator *Size = dyn_cast<BinaryOperator>(E);
5162  if (!Size)
5163    return false;
5164
5165  // if E is binop and op is >, <, >=, <=, ==, &&, ||:
5166  if (!Size->isComparisonOp() && !Size->isEqualityOp() && !Size->isLogicalOp())
5167    return false;
5168
5169  SourceRange SizeRange = Size->getSourceRange();
5170  S.Diag(Size->getOperatorLoc(), diag::warn_memsize_comparison)
5171      << SizeRange << FnName;
5172  S.Diag(FnLoc, diag::note_memsize_comparison_paren)
5173      << FnName << FixItHint::CreateInsertion(
5174                       S.getLocForEndOfToken(Size->getLHS()->getLocEnd()), ")")
5175      << FixItHint::CreateRemoval(RParenLoc);
5176  S.Diag(SizeRange.getBegin(), diag::note_memsize_comparison_cast_silence)
5177      << FixItHint::CreateInsertion(SizeRange.getBegin(), "(size_t)(")
5178      << FixItHint::CreateInsertion(S.getLocForEndOfToken(SizeRange.getEnd()),
5179                                    ")");
5180
5181  return true;
5182}
5183
5184/// \brief Determine whether the given type is or contains a dynamic class type
5185/// (e.g., whether it has a vtable).
5186static const CXXRecordDecl *getContainedDynamicClass(QualType T,
5187                                                     bool &IsContained) {
5188  // Look through array types while ignoring qualifiers.
5189  const Type *Ty = T->getBaseElementTypeUnsafe();
5190  IsContained = false;
5191
5192  const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
5193  RD = RD ? RD->getDefinition() : nullptr;
5194  if (!RD)
5195    return nullptr;
5196
5197  if (RD->isDynamicClass())
5198    return RD;
5199
5200  // Check all the fields.  If any bases were dynamic, the class is dynamic.
5201  // It's impossible for a class to transitively contain itself by value, so
5202  // infinite recursion is impossible.
5203  for (auto *FD : RD->fields()) {
5204    bool SubContained;
5205    if (const CXXRecordDecl *ContainedRD =
5206            getContainedDynamicClass(FD->getType(), SubContained)) {
5207      IsContained = true;
5208      return ContainedRD;
5209    }
5210  }
5211
5212  return nullptr;
5213}
5214
5215/// \brief If E is a sizeof expression, returns its argument expression,
5216/// otherwise returns NULL.
5217static const Expr *getSizeOfExprArg(const Expr *E) {
5218  if (const UnaryExprOrTypeTraitExpr *SizeOf =
5219      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
5220    if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
5221      return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
5222
5223  return nullptr;
5224}
5225
5226/// \brief If E is a sizeof expression, returns its argument type.
5227static QualType getSizeOfArgType(const Expr *E) {
5228  if (const UnaryExprOrTypeTraitExpr *SizeOf =
5229      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
5230    if (SizeOf->getKind() == clang::UETT_SizeOf)
5231      return SizeOf->getTypeOfArgument();
5232
5233  return QualType();
5234}
5235
5236/// \brief Check for dangerous or invalid arguments to memset().
5237///
5238/// This issues warnings on known problematic, dangerous or unspecified
5239/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
5240/// function calls.
5241///
5242/// \param Call The call expression to diagnose.
5243void Sema::CheckMemaccessArguments(const CallExpr *Call,
5244                                   unsigned BId,
5245                                   IdentifierInfo *FnName) {
5246  assert(BId != 0);
5247
5248  // It is possible to have a non-standard definition of memset.  Validate
5249  // we have enough arguments, and if not, abort further checking.
5250  unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
5251  if (Call->getNumArgs() < ExpectedNumArgs)
5252    return;
5253
5254  unsigned LastArg = (BId == Builtin::BImemset ||
5255                      BId == Builtin::BIstrndup ? 1 : 2);
5256  unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
5257  const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
5258
5259  if (CheckMemorySizeofForComparison(*this, LenExpr, FnName,
5260                                     Call->getLocStart(), Call->getRParenLoc()))
5261    return;
5262
5263  // We have special checking when the length is a sizeof expression.
5264  QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
5265  const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
5266  llvm::FoldingSetNodeID SizeOfArgID;
5267
5268  for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
5269    const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
5270    SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
5271
5272    QualType DestTy = Dest->getType();
5273    QualType PointeeTy;
5274    if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
5275      PointeeTy = DestPtrTy->getPointeeType();
5276
5277      // Never warn about void type pointers. This can be used to suppress
5278      // false positives.
5279      if (PointeeTy->isVoidType())
5280        continue;
5281
5282      // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
5283      // actually comparing the expressions for equality. Because computing the
5284      // expression IDs can be expensive, we only do this if the diagnostic is
5285      // enabled.
5286      if (SizeOfArg &&
5287          !Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess,
5288                           SizeOfArg->getExprLoc())) {
5289        // We only compute IDs for expressions if the warning is enabled, and
5290        // cache the sizeof arg's ID.
5291        if (SizeOfArgID == llvm::FoldingSetNodeID())
5292          SizeOfArg->Profile(SizeOfArgID, Context, true);
5293        llvm::FoldingSetNodeID DestID;
5294        Dest->Profile(DestID, Context, true);
5295        if (DestID == SizeOfArgID) {
5296          // TODO: For strncpy() and friends, this could suggest sizeof(dst)
5297          //       over sizeof(src) as well.
5298          unsigned ActionIdx = 0; // Default is to suggest dereferencing.
5299          StringRef ReadableName = FnName->getName();
5300
5301          if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
5302            if (UnaryOp->getOpcode() == UO_AddrOf)
5303              ActionIdx = 1; // If its an address-of operator, just remove it.
5304          if (!PointeeTy->isIncompleteType() &&
5305              (Context.getTypeSize(PointeeTy) == Context.getCharWidth()))
5306            ActionIdx = 2; // If the pointee's size is sizeof(char),
5307                           // suggest an explicit length.
5308
5309          // If the function is defined as a builtin macro, do not show macro
5310          // expansion.
5311          SourceLocation SL = SizeOfArg->getExprLoc();
5312          SourceRange DSR = Dest->getSourceRange();
5313          SourceRange SSR = SizeOfArg->getSourceRange();
5314          SourceManager &SM = getSourceManager();
5315
5316          if (SM.isMacroArgExpansion(SL)) {
5317            ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts);
5318            SL = SM.getSpellingLoc(SL);
5319            DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()),
5320                             SM.getSpellingLoc(DSR.getEnd()));
5321            SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()),
5322                             SM.getSpellingLoc(SSR.getEnd()));
5323          }
5324
5325          DiagRuntimeBehavior(SL, SizeOfArg,
5326                              PDiag(diag::warn_sizeof_pointer_expr_memaccess)
5327                                << ReadableName
5328                                << PointeeTy
5329                                << DestTy
5330                                << DSR
5331                                << SSR);
5332          DiagRuntimeBehavior(SL, SizeOfArg,
5333                         PDiag(diag::warn_sizeof_pointer_expr_memaccess_note)
5334                                << ActionIdx
5335                                << SSR);
5336
5337          break;
5338        }
5339      }
5340
5341      // Also check for cases where the sizeof argument is the exact same
5342      // type as the memory argument, and where it points to a user-defined
5343      // record type.
5344      if (SizeOfArgTy != QualType()) {
5345        if (PointeeTy->isRecordType() &&
5346            Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
5347          DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
5348                              PDiag(diag::warn_sizeof_pointer_type_memaccess)
5349                                << FnName << SizeOfArgTy << ArgIdx
5350                                << PointeeTy << Dest->getSourceRange()
5351                                << LenExpr->getSourceRange());
5352          break;
5353        }
5354      }
5355    } else if (DestTy->isArrayType()) {
5356      PointeeTy = DestTy;
5357    }
5358
5359    if (PointeeTy == QualType())
5360      continue;
5361
5362    // Always complain about dynamic classes.
5363    bool IsContained;
5364    if (const CXXRecordDecl *ContainedRD =
5365            getContainedDynamicClass(PointeeTy, IsContained)) {
5366
5367      unsigned OperationType = 0;
5368      // "overwritten" if we're warning about the destination for any call
5369      // but memcmp; otherwise a verb appropriate to the call.
5370      if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
5371        if (BId == Builtin::BImemcpy)
5372          OperationType = 1;
5373        else if(BId == Builtin::BImemmove)
5374          OperationType = 2;
5375        else if (BId == Builtin::BImemcmp)
5376          OperationType = 3;
5377      }
5378
5379      DiagRuntimeBehavior(
5380        Dest->getExprLoc(), Dest,
5381        PDiag(diag::warn_dyn_class_memaccess)
5382          << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
5383          << FnName << IsContained << ContainedRD << OperationType
5384          << Call->getCallee()->getSourceRange());
5385    } else if (PointeeTy.hasNonTrivialObjCLifetime() &&
5386             BId != Builtin::BImemset)
5387      DiagRuntimeBehavior(
5388        Dest->getExprLoc(), Dest,
5389        PDiag(diag::warn_arc_object_memaccess)
5390          << ArgIdx << FnName << PointeeTy
5391          << Call->getCallee()->getSourceRange());
5392    else
5393      continue;
5394
5395    DiagRuntimeBehavior(
5396      Dest->getExprLoc(), Dest,
5397      PDiag(diag::note_bad_memaccess_silence)
5398        << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
5399    break;
5400  }
5401
5402}
5403
5404// A little helper routine: ignore addition and subtraction of integer literals.
5405// This intentionally does not ignore all integer constant expressions because
5406// we don't want to remove sizeof().
5407static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
5408  Ex = Ex->IgnoreParenCasts();
5409
5410  for (;;) {
5411    const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
5412    if (!BO || !BO->isAdditiveOp())
5413      break;
5414
5415    const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
5416    const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
5417
5418    if (isa<IntegerLiteral>(RHS))
5419      Ex = LHS;
5420    else if (isa<IntegerLiteral>(LHS))
5421      Ex = RHS;
5422    else
5423      break;
5424  }
5425
5426  return Ex;
5427}
5428
5429static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty,
5430                                                      ASTContext &Context) {
5431  // Only handle constant-sized or VLAs, but not flexible members.
5432  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) {
5433    // Only issue the FIXIT for arrays of size > 1.
5434    if (CAT->getSize().getSExtValue() <= 1)
5435      return false;
5436  } else if (!Ty->isVariableArrayType()) {
5437    return false;
5438  }
5439  return true;
5440}
5441
5442// Warn if the user has made the 'size' argument to strlcpy or strlcat
5443// be the size of the source, instead of the destination.
5444void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
5445                                    IdentifierInfo *FnName) {
5446
5447  // Don't crash if the user has the wrong number of arguments
5448  unsigned NumArgs = Call->getNumArgs();
5449  if ((NumArgs != 3) && (NumArgs != 4))
5450    return;
5451
5452  const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
5453  const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
5454  const Expr *CompareWithSrc = nullptr;
5455
5456  if (CheckMemorySizeofForComparison(*this, SizeArg, FnName,
5457                                     Call->getLocStart(), Call->getRParenLoc()))
5458    return;
5459
5460  // Look for 'strlcpy(dst, x, sizeof(x))'
5461  if (const Expr *Ex = getSizeOfExprArg(SizeArg))
5462    CompareWithSrc = Ex;
5463  else {
5464    // Look for 'strlcpy(dst, x, strlen(x))'
5465    if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
5466      if (SizeCall->getBuiltinCallee() == Builtin::BIstrlen &&
5467          SizeCall->getNumArgs() == 1)
5468        CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
5469    }
5470  }
5471
5472  if (!CompareWithSrc)
5473    return;
5474
5475  // Determine if the argument to sizeof/strlen is equal to the source
5476  // argument.  In principle there's all kinds of things you could do
5477  // here, for instance creating an == expression and evaluating it with
5478  // EvaluateAsBooleanCondition, but this uses a more direct technique:
5479  const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
5480  if (!SrcArgDRE)
5481    return;
5482
5483  const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
5484  if (!CompareWithSrcDRE ||
5485      SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
5486    return;
5487
5488  const Expr *OriginalSizeArg = Call->getArg(2);
5489  Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
5490    << OriginalSizeArg->getSourceRange() << FnName;
5491
5492  // Output a FIXIT hint if the destination is an array (rather than a
5493  // pointer to an array).  This could be enhanced to handle some
5494  // pointers if we know the actual size, like if DstArg is 'array+2'
5495  // we could say 'sizeof(array)-2'.
5496  const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
5497  if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context))
5498    return;
5499
5500  SmallString<128> sizeString;
5501  llvm::raw_svector_ostream OS(sizeString);
5502  OS << "sizeof(";
5503  DstArg->printPretty(OS, nullptr, getPrintingPolicy());
5504  OS << ")";
5505
5506  Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
5507    << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
5508                                    OS.str());
5509}
5510
5511/// Check if two expressions refer to the same declaration.
5512static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
5513  if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
5514    if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
5515      return D1->getDecl() == D2->getDecl();
5516  return false;
5517}
5518
5519static const Expr *getStrlenExprArg(const Expr *E) {
5520  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
5521    const FunctionDecl *FD = CE->getDirectCallee();
5522    if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
5523      return nullptr;
5524    return CE->getArg(0)->IgnoreParenCasts();
5525  }
5526  return nullptr;
5527}
5528
5529// Warn on anti-patterns as the 'size' argument to strncat.
5530// The correct size argument should look like following:
5531//   strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
5532void Sema::CheckStrncatArguments(const CallExpr *CE,
5533                                 IdentifierInfo *FnName) {
5534  // Don't crash if the user has the wrong number of arguments.
5535  if (CE->getNumArgs() < 3)
5536    return;
5537  const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
5538  const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
5539  const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
5540
5541  if (CheckMemorySizeofForComparison(*this, LenArg, FnName, CE->getLocStart(),
5542                                     CE->getRParenLoc()))
5543    return;
5544
5545  // Identify common expressions, which are wrongly used as the size argument
5546  // to strncat and may lead to buffer overflows.
5547  unsigned PatternType = 0;
5548  if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
5549    // - sizeof(dst)
5550    if (referToTheSameDecl(SizeOfArg, DstArg))
5551      PatternType = 1;
5552    // - sizeof(src)
5553    else if (referToTheSameDecl(SizeOfArg, SrcArg))
5554      PatternType = 2;
5555  } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
5556    if (BE->getOpcode() == BO_Sub) {
5557      const Expr *L = BE->getLHS()->IgnoreParenCasts();
5558      const Expr *R = BE->getRHS()->IgnoreParenCasts();
5559      // - sizeof(dst) - strlen(dst)
5560      if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
5561          referToTheSameDecl(DstArg, getStrlenExprArg(R)))
5562        PatternType = 1;
5563      // - sizeof(src) - (anything)
5564      else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
5565        PatternType = 2;
5566    }
5567  }
5568
5569  if (PatternType == 0)
5570    return;
5571
5572  // Generate the diagnostic.
5573  SourceLocation SL = LenArg->getLocStart();
5574  SourceRange SR = LenArg->getSourceRange();
5575  SourceManager &SM = getSourceManager();
5576
5577  // If the function is defined as a builtin macro, do not show macro expansion.
5578  if (SM.isMacroArgExpansion(SL)) {
5579    SL = SM.getSpellingLoc(SL);
5580    SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
5581                     SM.getSpellingLoc(SR.getEnd()));
5582  }
5583
5584  // Check if the destination is an array (rather than a pointer to an array).
5585  QualType DstTy = DstArg->getType();
5586  bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy,
5587                                                                    Context);
5588  if (!isKnownSizeArray) {
5589    if (PatternType == 1)
5590      Diag(SL, diag::warn_strncat_wrong_size) << SR;
5591    else
5592      Diag(SL, diag::warn_strncat_src_size) << SR;
5593    return;
5594  }
5595
5596  if (PatternType == 1)
5597    Diag(SL, diag::warn_strncat_large_size) << SR;
5598  else
5599    Diag(SL, diag::warn_strncat_src_size) << SR;
5600
5601  SmallString<128> sizeString;
5602  llvm::raw_svector_ostream OS(sizeString);
5603  OS << "sizeof(";
5604  DstArg->printPretty(OS, nullptr, getPrintingPolicy());
5605  OS << ") - ";
5606  OS << "strlen(";
5607  DstArg->printPretty(OS, nullptr, getPrintingPolicy());
5608  OS << ") - 1";
5609
5610  Diag(SL, diag::note_strncat_wrong_size)
5611    << FixItHint::CreateReplacement(SR, OS.str());
5612}
5613
5614//===--- CHECK: Return Address of Stack Variable --------------------------===//
5615
5616static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
5617                     Decl *ParentDecl);
5618static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars,
5619                      Decl *ParentDecl);
5620
5621/// CheckReturnStackAddr - Check if a return statement returns the address
5622///   of a stack variable.
5623static void
5624CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
5625                     SourceLocation ReturnLoc) {
5626
5627  Expr *stackE = nullptr;
5628  SmallVector<DeclRefExpr *, 8> refVars;
5629
5630  // Perform checking for returned stack addresses, local blocks,
5631  // label addresses or references to temporaries.
5632  if (lhsType->isPointerType() ||
5633      (!S.getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
5634    stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/nullptr);
5635  } else if (lhsType->isReferenceType()) {
5636    stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/nullptr);
5637  }
5638
5639  if (!stackE)
5640    return; // Nothing suspicious was found.
5641
5642  SourceLocation diagLoc;
5643  SourceRange diagRange;
5644  if (refVars.empty()) {
5645    diagLoc = stackE->getLocStart();
5646    diagRange = stackE->getSourceRange();
5647  } else {
5648    // We followed through a reference variable. 'stackE' contains the
5649    // problematic expression but we will warn at the return statement pointing
5650    // at the reference variable. We will later display the "trail" of
5651    // reference variables using notes.
5652    diagLoc = refVars[0]->getLocStart();
5653    diagRange = refVars[0]->getSourceRange();
5654  }
5655
5656  if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
5657    S.Diag(diagLoc, diag::warn_ret_stack_addr_ref) << lhsType->isReferenceType()
5658     << DR->getDecl()->getDeclName() << diagRange;
5659  } else if (isa<BlockExpr>(stackE)) { // local block.
5660    S.Diag(diagLoc, diag::err_ret_local_block) << diagRange;
5661  } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
5662    S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
5663  } else { // local temporary.
5664    S.Diag(diagLoc, diag::warn_ret_local_temp_addr_ref)
5665     << lhsType->isReferenceType() << diagRange;
5666  }
5667
5668  // Display the "trail" of reference variables that we followed until we
5669  // found the problematic expression using notes.
5670  for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
5671    VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
5672    // If this var binds to another reference var, show the range of the next
5673    // var, otherwise the var binds to the problematic expression, in which case
5674    // show the range of the expression.
5675    SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
5676                                  : stackE->getSourceRange();
5677    S.Diag(VD->getLocation(), diag::note_ref_var_local_bind)
5678        << VD->getDeclName() << range;
5679  }
5680}
5681
5682/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
5683///  check if the expression in a return statement evaluates to an address
5684///  to a location on the stack, a local block, an address of a label, or a
5685///  reference to local temporary. The recursion is used to traverse the
5686///  AST of the return expression, with recursion backtracking when we
5687///  encounter a subexpression that (1) clearly does not lead to one of the
5688///  above problematic expressions (2) is something we cannot determine leads to
5689///  a problematic expression based on such local checking.
5690///
5691///  Both EvalAddr and EvalVal follow through reference variables to evaluate
5692///  the expression that they point to. Such variables are added to the
5693///  'refVars' vector so that we know what the reference variable "trail" was.
5694///
5695///  EvalAddr processes expressions that are pointers that are used as
5696///  references (and not L-values).  EvalVal handles all other values.
5697///  At the base case of the recursion is a check for the above problematic
5698///  expressions.
5699///
5700///  This implementation handles:
5701///
5702///   * pointer-to-pointer casts
5703///   * implicit conversions from array references to pointers
5704///   * taking the address of fields
5705///   * arbitrary interplay between "&" and "*" operators
5706///   * pointer arithmetic from an address of a stack variable
5707///   * taking the address of an array element where the array is on the stack
5708static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
5709                      Decl *ParentDecl) {
5710  if (E->isTypeDependent())
5711    return nullptr;
5712
5713  // We should only be called for evaluating pointer expressions.
5714  assert((E->getType()->isAnyPointerType() ||
5715          E->getType()->isBlockPointerType() ||
5716          E->getType()->isObjCQualifiedIdType()) &&
5717         "EvalAddr only works on pointers");
5718
5719  E = E->IgnoreParens();
5720
5721  // Our "symbolic interpreter" is just a dispatch off the currently
5722  // viewed AST node.  We then recursively traverse the AST by calling
5723  // EvalAddr and EvalVal appropriately.
5724  switch (E->getStmtClass()) {
5725  case Stmt::DeclRefExprClass: {
5726    DeclRefExpr *DR = cast<DeclRefExpr>(E);
5727
5728    // If we leave the immediate function, the lifetime isn't about to end.
5729    if (DR->refersToEnclosingVariableOrCapture())
5730      return nullptr;
5731
5732    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
5733      // If this is a reference variable, follow through to the expression that
5734      // it points to.
5735      if (V->hasLocalStorage() &&
5736          V->getType()->isReferenceType() && V->hasInit()) {
5737        // Add the reference variable to the "trail".
5738        refVars.push_back(DR);
5739        return EvalAddr(V->getInit(), refVars, ParentDecl);
5740      }
5741
5742    return nullptr;
5743  }
5744
5745  case Stmt::UnaryOperatorClass: {
5746    // The only unary operator that make sense to handle here
5747    // is AddrOf.  All others don't make sense as pointers.
5748    UnaryOperator *U = cast<UnaryOperator>(E);
5749
5750    if (U->getOpcode() == UO_AddrOf)
5751      return EvalVal(U->getSubExpr(), refVars, ParentDecl);
5752    else
5753      return nullptr;
5754  }
5755
5756  case Stmt::BinaryOperatorClass: {
5757    // Handle pointer arithmetic.  All other binary operators are not valid
5758    // in this context.
5759    BinaryOperator *B = cast<BinaryOperator>(E);
5760    BinaryOperatorKind op = B->getOpcode();
5761
5762    if (op != BO_Add && op != BO_Sub)
5763      return nullptr;
5764
5765    Expr *Base = B->getLHS();
5766
5767    // Determine which argument is the real pointer base.  It could be
5768    // the RHS argument instead of the LHS.
5769    if (!Base->getType()->isPointerType()) Base = B->getRHS();
5770
5771    assert (Base->getType()->isPointerType());
5772    return EvalAddr(Base, refVars, ParentDecl);
5773  }
5774
5775  // For conditional operators we need to see if either the LHS or RHS are
5776  // valid DeclRefExpr*s.  If one of them is valid, we return it.
5777  case Stmt::ConditionalOperatorClass: {
5778    ConditionalOperator *C = cast<ConditionalOperator>(E);
5779
5780    // Handle the GNU extension for missing LHS.
5781    // FIXME: That isn't a ConditionalOperator, so doesn't get here.
5782    if (Expr *LHSExpr = C->getLHS()) {
5783      // In C++, we can have a throw-expression, which has 'void' type.
5784      if (!LHSExpr->getType()->isVoidType())
5785        if (Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl))
5786          return LHS;
5787    }
5788
5789    // In C++, we can have a throw-expression, which has 'void' type.
5790    if (C->getRHS()->getType()->isVoidType())
5791      return nullptr;
5792
5793    return EvalAddr(C->getRHS(), refVars, ParentDecl);
5794  }
5795
5796  case Stmt::BlockExprClass:
5797    if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
5798      return E; // local block.
5799    return nullptr;
5800
5801  case Stmt::AddrLabelExprClass:
5802    return E; // address of label.
5803
5804  case Stmt::ExprWithCleanupsClass:
5805    return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
5806                    ParentDecl);
5807
5808  // For casts, we need to handle conversions from arrays to
5809  // pointer values, and pointer-to-pointer conversions.
5810  case Stmt::ImplicitCastExprClass:
5811  case Stmt::CStyleCastExprClass:
5812  case Stmt::CXXFunctionalCastExprClass:
5813  case Stmt::ObjCBridgedCastExprClass:
5814  case Stmt::CXXStaticCastExprClass:
5815  case Stmt::CXXDynamicCastExprClass:
5816  case Stmt::CXXConstCastExprClass:
5817  case Stmt::CXXReinterpretCastExprClass: {
5818    Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
5819    switch (cast<CastExpr>(E)->getCastKind()) {
5820    case CK_LValueToRValue:
5821    case CK_NoOp:
5822    case CK_BaseToDerived:
5823    case CK_DerivedToBase:
5824    case CK_UncheckedDerivedToBase:
5825    case CK_Dynamic:
5826    case CK_CPointerToObjCPointerCast:
5827    case CK_BlockPointerToObjCPointerCast:
5828    case CK_AnyPointerToBlockPointerCast:
5829      return EvalAddr(SubExpr, refVars, ParentDecl);
5830
5831    case CK_ArrayToPointerDecay:
5832      return EvalVal(SubExpr, refVars, ParentDecl);
5833
5834    case CK_BitCast:
5835      if (SubExpr->getType()->isAnyPointerType() ||
5836          SubExpr->getType()->isBlockPointerType() ||
5837          SubExpr->getType()->isObjCQualifiedIdType())
5838        return EvalAddr(SubExpr, refVars, ParentDecl);
5839      else
5840        return nullptr;
5841
5842    default:
5843      return nullptr;
5844    }
5845  }
5846
5847  case Stmt::MaterializeTemporaryExprClass:
5848    if (Expr *Result = EvalAddr(
5849                         cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
5850                                refVars, ParentDecl))
5851      return Result;
5852
5853    return E;
5854
5855  // Everything else: we simply don't reason about them.
5856  default:
5857    return nullptr;
5858  }
5859}
5860
5861
5862///  EvalVal - This function is complements EvalAddr in the mutual recursion.
5863///   See the comments for EvalAddr for more details.
5864static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
5865                     Decl *ParentDecl) {
5866do {
5867  // We should only be called for evaluating non-pointer expressions, or
5868  // expressions with a pointer type that are not used as references but instead
5869  // are l-values (e.g., DeclRefExpr with a pointer type).
5870
5871  // Our "symbolic interpreter" is just a dispatch off the currently
5872  // viewed AST node.  We then recursively traverse the AST by calling
5873  // EvalAddr and EvalVal appropriately.
5874
5875  E = E->IgnoreParens();
5876  switch (E->getStmtClass()) {
5877  case Stmt::ImplicitCastExprClass: {
5878    ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
5879    if (IE->getValueKind() == VK_LValue) {
5880      E = IE->getSubExpr();
5881      continue;
5882    }
5883    return nullptr;
5884  }
5885
5886  case Stmt::ExprWithCleanupsClass:
5887    return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl);
5888
5889  case Stmt::DeclRefExprClass: {
5890    // When we hit a DeclRefExpr we are looking at code that refers to a
5891    // variable's name. If it's not a reference variable we check if it has
5892    // local storage within the function, and if so, return the expression.
5893    DeclRefExpr *DR = cast<DeclRefExpr>(E);
5894
5895    // If we leave the immediate function, the lifetime isn't about to end.
5896    if (DR->refersToEnclosingVariableOrCapture())
5897      return nullptr;
5898
5899    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
5900      // Check if it refers to itself, e.g. "int& i = i;".
5901      if (V == ParentDecl)
5902        return DR;
5903
5904      if (V->hasLocalStorage()) {
5905        if (!V->getType()->isReferenceType())
5906          return DR;
5907
5908        // Reference variable, follow through to the expression that
5909        // it points to.
5910        if (V->hasInit()) {
5911          // Add the reference variable to the "trail".
5912          refVars.push_back(DR);
5913          return EvalVal(V->getInit(), refVars, V);
5914        }
5915      }
5916    }
5917
5918    return nullptr;
5919  }
5920
5921  case Stmt::UnaryOperatorClass: {
5922    // The only unary operator that make sense to handle here
5923    // is Deref.  All others don't resolve to a "name."  This includes
5924    // handling all sorts of rvalues passed to a unary operator.
5925    UnaryOperator *U = cast<UnaryOperator>(E);
5926
5927    if (U->getOpcode() == UO_Deref)
5928      return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
5929
5930    return nullptr;
5931  }
5932
5933  case Stmt::ArraySubscriptExprClass: {
5934    // Array subscripts are potential references to data on the stack.  We
5935    // retrieve the DeclRefExpr* for the array variable if it indeed
5936    // has local storage.
5937    return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl);
5938  }
5939
5940  case Stmt::OMPArraySectionExprClass: {
5941    return EvalAddr(cast<OMPArraySectionExpr>(E)->getBase(), refVars,
5942                    ParentDecl);
5943  }
5944
5945  case Stmt::ConditionalOperatorClass: {
5946    // For conditional operators we need to see if either the LHS or RHS are
5947    // non-NULL Expr's.  If one is non-NULL, we return it.
5948    ConditionalOperator *C = cast<ConditionalOperator>(E);
5949
5950    // Handle the GNU extension for missing LHS.
5951    if (Expr *LHSExpr = C->getLHS()) {
5952      // In C++, we can have a throw-expression, which has 'void' type.
5953      if (!LHSExpr->getType()->isVoidType())
5954        if (Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl))
5955          return LHS;
5956    }
5957
5958    // In C++, we can have a throw-expression, which has 'void' type.
5959    if (C->getRHS()->getType()->isVoidType())
5960      return nullptr;
5961
5962    return EvalVal(C->getRHS(), refVars, ParentDecl);
5963  }
5964
5965  // Accesses to members are potential references to data on the stack.
5966  case Stmt::MemberExprClass: {
5967    MemberExpr *M = cast<MemberExpr>(E);
5968
5969    // Check for indirect access.  We only want direct field accesses.
5970    if (M->isArrow())
5971      return nullptr;
5972
5973    // Check whether the member type is itself a reference, in which case
5974    // we're not going to refer to the member, but to what the member refers to.
5975    if (M->getMemberDecl()->getType()->isReferenceType())
5976      return nullptr;
5977
5978    return EvalVal(M->getBase(), refVars, ParentDecl);
5979  }
5980
5981  case Stmt::MaterializeTemporaryExprClass:
5982    if (Expr *Result = EvalVal(
5983                          cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
5984                               refVars, ParentDecl))
5985      return Result;
5986
5987    return E;
5988
5989  default:
5990    // Check that we don't return or take the address of a reference to a
5991    // temporary. This is only useful in C++.
5992    if (!E->isTypeDependent() && E->isRValue())
5993      return E;
5994
5995    // Everything else: we simply don't reason about them.
5996    return nullptr;
5997  }
5998} while (true);
5999}
6000
6001void
6002Sema::CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
6003                         SourceLocation ReturnLoc,
6004                         bool isObjCMethod,
6005                         const AttrVec *Attrs,
6006                         const FunctionDecl *FD) {
6007  CheckReturnStackAddr(*this, RetValExp, lhsType, ReturnLoc);
6008
6009  // Check if the return value is null but should not be.
6010  if (((Attrs && hasSpecificAttr<ReturnsNonNullAttr>(*Attrs)) ||
6011       (!isObjCMethod && isNonNullType(Context, lhsType))) &&
6012      CheckNonNullExpr(*this, RetValExp))
6013    Diag(ReturnLoc, diag::warn_null_ret)
6014      << (isObjCMethod ? 1 : 0) << RetValExp->getSourceRange();
6015
6016  // C++11 [basic.stc.dynamic.allocation]p4:
6017  //   If an allocation function declared with a non-throwing
6018  //   exception-specification fails to allocate storage, it shall return
6019  //   a null pointer. Any other allocation function that fails to allocate
6020  //   storage shall indicate failure only by throwing an exception [...]
6021  if (FD) {
6022    OverloadedOperatorKind Op = FD->getOverloadedOperator();
6023    if (Op == OO_New || Op == OO_Array_New) {
6024      const FunctionProtoType *Proto
6025        = FD->getType()->castAs<FunctionProtoType>();
6026      if (!Proto->isNothrow(Context, /*ResultIfDependent*/true) &&
6027          CheckNonNullExpr(*this, RetValExp))
6028        Diag(ReturnLoc, diag::warn_operator_new_returns_null)
6029          << FD << getLangOpts().CPlusPlus11;
6030    }
6031  }
6032}
6033
6034//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
6035
6036/// Check for comparisons of floating point operands using != and ==.
6037/// Issue a warning if these are no self-comparisons, as they are not likely
6038/// to do what the programmer intended.
6039void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
6040  Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
6041  Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
6042
6043  // Special case: check for x == x (which is OK).
6044  // Do not emit warnings for such cases.
6045  if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
6046    if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
6047      if (DRL->getDecl() == DRR->getDecl())
6048        return;
6049
6050
6051  // Special case: check for comparisons against literals that can be exactly
6052  //  represented by APFloat.  In such cases, do not emit a warning.  This
6053  //  is a heuristic: often comparison against such literals are used to
6054  //  detect if a value in a variable has not changed.  This clearly can
6055  //  lead to false negatives.
6056  if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
6057    if (FLL->isExact())
6058      return;
6059  } else
6060    if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen))
6061      if (FLR->isExact())
6062        return;
6063
6064  // Check for comparisons with builtin types.
6065  if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
6066    if (CL->getBuiltinCallee())
6067      return;
6068
6069  if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
6070    if (CR->getBuiltinCallee())
6071      return;
6072
6073  // Emit the diagnostic.
6074  Diag(Loc, diag::warn_floatingpoint_eq)
6075    << LHS->getSourceRange() << RHS->getSourceRange();
6076}
6077
6078//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
6079//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
6080
6081namespace {
6082
6083/// Structure recording the 'active' range of an integer-valued
6084/// expression.
6085struct IntRange {
6086  /// The number of bits active in the int.
6087  unsigned Width;
6088
6089  /// True if the int is known not to have negative values.
6090  bool NonNegative;
6091
6092  IntRange(unsigned Width, bool NonNegative)
6093    : Width(Width), NonNegative(NonNegative)
6094  {}
6095
6096  /// Returns the range of the bool type.
6097  static IntRange forBoolType() {
6098    return IntRange(1, true);
6099  }
6100
6101  /// Returns the range of an opaque value of the given integral type.
6102  static IntRange forValueOfType(ASTContext &C, QualType T) {
6103    return forValueOfCanonicalType(C,
6104                          T->getCanonicalTypeInternal().getTypePtr());
6105  }
6106
6107  /// Returns the range of an opaque value of a canonical integral type.
6108  static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
6109    assert(T->isCanonicalUnqualified());
6110
6111    if (const VectorType *VT = dyn_cast<VectorType>(T))
6112      T = VT->getElementType().getTypePtr();
6113    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
6114      T = CT->getElementType().getTypePtr();
6115    if (const AtomicType *AT = dyn_cast<AtomicType>(T))
6116      T = AT->getValueType().getTypePtr();
6117
6118    // For enum types, use the known bit width of the enumerators.
6119    if (const EnumType *ET = dyn_cast<EnumType>(T)) {
6120      EnumDecl *Enum = ET->getDecl();
6121      if (!Enum->isCompleteDefinition())
6122        return IntRange(C.getIntWidth(QualType(T, 0)), false);
6123
6124      unsigned NumPositive = Enum->getNumPositiveBits();
6125      unsigned NumNegative = Enum->getNumNegativeBits();
6126
6127      if (NumNegative == 0)
6128        return IntRange(NumPositive, true/*NonNegative*/);
6129      else
6130        return IntRange(std::max(NumPositive + 1, NumNegative),
6131                        false/*NonNegative*/);
6132    }
6133
6134    const BuiltinType *BT = cast<BuiltinType>(T);
6135    assert(BT->isInteger());
6136
6137    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
6138  }
6139
6140  /// Returns the "target" range of a canonical integral type, i.e.
6141  /// the range of values expressible in the type.
6142  ///
6143  /// This matches forValueOfCanonicalType except that enums have the
6144  /// full range of their type, not the range of their enumerators.
6145  static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
6146    assert(T->isCanonicalUnqualified());
6147
6148    if (const VectorType *VT = dyn_cast<VectorType>(T))
6149      T = VT->getElementType().getTypePtr();
6150    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
6151      T = CT->getElementType().getTypePtr();
6152    if (const AtomicType *AT = dyn_cast<AtomicType>(T))
6153      T = AT->getValueType().getTypePtr();
6154    if (const EnumType *ET = dyn_cast<EnumType>(T))
6155      T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
6156
6157    const BuiltinType *BT = cast<BuiltinType>(T);
6158    assert(BT->isInteger());
6159
6160    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
6161  }
6162
6163  /// Returns the supremum of two ranges: i.e. their conservative merge.
6164  static IntRange join(IntRange L, IntRange R) {
6165    return IntRange(std::max(L.Width, R.Width),
6166                    L.NonNegative && R.NonNegative);
6167  }
6168
6169  /// Returns the infinum of two ranges: i.e. their aggressive merge.
6170  static IntRange meet(IntRange L, IntRange R) {
6171    return IntRange(std::min(L.Width, R.Width),
6172                    L.NonNegative || R.NonNegative);
6173  }
6174};
6175
6176static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value,
6177                              unsigned MaxWidth) {
6178  if (value.isSigned() && value.isNegative())
6179    return IntRange(value.getMinSignedBits(), false);
6180
6181  if (value.getBitWidth() > MaxWidth)
6182    value = value.trunc(MaxWidth);
6183
6184  // isNonNegative() just checks the sign bit without considering
6185  // signedness.
6186  return IntRange(value.getActiveBits(), true);
6187}
6188
6189static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
6190                              unsigned MaxWidth) {
6191  if (result.isInt())
6192    return GetValueRange(C, result.getInt(), MaxWidth);
6193
6194  if (result.isVector()) {
6195    IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
6196    for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
6197      IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
6198      R = IntRange::join(R, El);
6199    }
6200    return R;
6201  }
6202
6203  if (result.isComplexInt()) {
6204    IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
6205    IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
6206    return IntRange::join(R, I);
6207  }
6208
6209  // This can happen with lossless casts to intptr_t of "based" lvalues.
6210  // Assume it might use arbitrary bits.
6211  // FIXME: The only reason we need to pass the type in here is to get
6212  // the sign right on this one case.  It would be nice if APValue
6213  // preserved this.
6214  assert(result.isLValue() || result.isAddrLabelDiff());
6215  return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
6216}
6217
6218static QualType GetExprType(Expr *E) {
6219  QualType Ty = E->getType();
6220  if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>())
6221    Ty = AtomicRHS->getValueType();
6222  return Ty;
6223}
6224
6225/// Pseudo-evaluate the given integer expression, estimating the
6226/// range of values it might take.
6227///
6228/// \param MaxWidth - the width to which the value will be truncated
6229static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
6230  E = E->IgnoreParens();
6231
6232  // Try a full evaluation first.
6233  Expr::EvalResult result;
6234  if (E->EvaluateAsRValue(result, C))
6235    return GetValueRange(C, result.Val, GetExprType(E), MaxWidth);
6236
6237  // I think we only want to look through implicit casts here; if the
6238  // user has an explicit widening cast, we should treat the value as
6239  // being of the new, wider type.
6240  if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
6241    if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
6242      return GetExprRange(C, CE->getSubExpr(), MaxWidth);
6243
6244    IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE));
6245
6246    bool isIntegerCast = CE->getCastKind() == CK_IntegralCast ||
6247                         CE->getCastKind() == CK_BooleanToSignedIntegral;
6248
6249    // Assume that non-integer casts can span the full range of the type.
6250    if (!isIntegerCast)
6251      return OutputTypeRange;
6252
6253    IntRange SubRange
6254      = GetExprRange(C, CE->getSubExpr(),
6255                     std::min(MaxWidth, OutputTypeRange.Width));
6256
6257    // Bail out if the subexpr's range is as wide as the cast type.
6258    if (SubRange.Width >= OutputTypeRange.Width)
6259      return OutputTypeRange;
6260
6261    // Otherwise, we take the smaller width, and we're non-negative if
6262    // either the output type or the subexpr is.
6263    return IntRange(SubRange.Width,
6264                    SubRange.NonNegative || OutputTypeRange.NonNegative);
6265  }
6266
6267  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
6268    // If we can fold the condition, just take that operand.
6269    bool CondResult;
6270    if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
6271      return GetExprRange(C, CondResult ? CO->getTrueExpr()
6272                                        : CO->getFalseExpr(),
6273                          MaxWidth);
6274
6275    // Otherwise, conservatively merge.
6276    IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
6277    IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
6278    return IntRange::join(L, R);
6279  }
6280
6281  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
6282    switch (BO->getOpcode()) {
6283
6284    // Boolean-valued operations are single-bit and positive.
6285    case BO_LAnd:
6286    case BO_LOr:
6287    case BO_LT:
6288    case BO_GT:
6289    case BO_LE:
6290    case BO_GE:
6291    case BO_EQ:
6292    case BO_NE:
6293      return IntRange::forBoolType();
6294
6295    // The type of the assignments is the type of the LHS, so the RHS
6296    // is not necessarily the same type.
6297    case BO_MulAssign:
6298    case BO_DivAssign:
6299    case BO_RemAssign:
6300    case BO_AddAssign:
6301    case BO_SubAssign:
6302    case BO_XorAssign:
6303    case BO_OrAssign:
6304      // TODO: bitfields?
6305      return IntRange::forValueOfType(C, GetExprType(E));
6306
6307    // Simple assignments just pass through the RHS, which will have
6308    // been coerced to the LHS type.
6309    case BO_Assign:
6310      // TODO: bitfields?
6311      return GetExprRange(C, BO->getRHS(), MaxWidth);
6312
6313    // Operations with opaque sources are black-listed.
6314    case BO_PtrMemD:
6315    case BO_PtrMemI:
6316      return IntRange::forValueOfType(C, GetExprType(E));
6317
6318    // Bitwise-and uses the *infinum* of the two source ranges.
6319    case BO_And:
6320    case BO_AndAssign:
6321      return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
6322                            GetExprRange(C, BO->getRHS(), MaxWidth));
6323
6324    // Left shift gets black-listed based on a judgement call.
6325    case BO_Shl:
6326      // ...except that we want to treat '1 << (blah)' as logically
6327      // positive.  It's an important idiom.
6328      if (IntegerLiteral *I
6329            = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
6330        if (I->getValue() == 1) {
6331          IntRange R = IntRange::forValueOfType(C, GetExprType(E));
6332          return IntRange(R.Width, /*NonNegative*/ true);
6333        }
6334      }
6335      // fallthrough
6336
6337    case BO_ShlAssign:
6338      return IntRange::forValueOfType(C, GetExprType(E));
6339
6340    // Right shift by a constant can narrow its left argument.
6341    case BO_Shr:
6342    case BO_ShrAssign: {
6343      IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
6344
6345      // If the shift amount is a positive constant, drop the width by
6346      // that much.
6347      llvm::APSInt shift;
6348      if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
6349          shift.isNonNegative()) {
6350        unsigned zext = shift.getZExtValue();
6351        if (zext >= L.Width)
6352          L.Width = (L.NonNegative ? 0 : 1);
6353        else
6354          L.Width -= zext;
6355      }
6356
6357      return L;
6358    }
6359
6360    // Comma acts as its right operand.
6361    case BO_Comma:
6362      return GetExprRange(C, BO->getRHS(), MaxWidth);
6363
6364    // Black-list pointer subtractions.
6365    case BO_Sub:
6366      if (BO->getLHS()->getType()->isPointerType())
6367        return IntRange::forValueOfType(C, GetExprType(E));
6368      break;
6369
6370    // The width of a division result is mostly determined by the size
6371    // of the LHS.
6372    case BO_Div: {
6373      // Don't 'pre-truncate' the operands.
6374      unsigned opWidth = C.getIntWidth(GetExprType(E));
6375      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
6376
6377      // If the divisor is constant, use that.
6378      llvm::APSInt divisor;
6379      if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
6380        unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
6381        if (log2 >= L.Width)
6382          L.Width = (L.NonNegative ? 0 : 1);
6383        else
6384          L.Width = std::min(L.Width - log2, MaxWidth);
6385        return L;
6386      }
6387
6388      // Otherwise, just use the LHS's width.
6389      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
6390      return IntRange(L.Width, L.NonNegative && R.NonNegative);
6391    }
6392
6393    // The result of a remainder can't be larger than the result of
6394    // either side.
6395    case BO_Rem: {
6396      // Don't 'pre-truncate' the operands.
6397      unsigned opWidth = C.getIntWidth(GetExprType(E));
6398      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
6399      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
6400
6401      IntRange meet = IntRange::meet(L, R);
6402      meet.Width = std::min(meet.Width, MaxWidth);
6403      return meet;
6404    }
6405
6406    // The default behavior is okay for these.
6407    case BO_Mul:
6408    case BO_Add:
6409    case BO_Xor:
6410    case BO_Or:
6411      break;
6412    }
6413
6414    // The default case is to treat the operation as if it were closed
6415    // on the narrowest type that encompasses both operands.
6416    IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
6417    IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
6418    return IntRange::join(L, R);
6419  }
6420
6421  if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
6422    switch (UO->getOpcode()) {
6423    // Boolean-valued operations are white-listed.
6424    case UO_LNot:
6425      return IntRange::forBoolType();
6426
6427    // Operations with opaque sources are black-listed.
6428    case UO_Deref:
6429    case UO_AddrOf: // should be impossible
6430      return IntRange::forValueOfType(C, GetExprType(E));
6431
6432    default:
6433      return GetExprRange(C, UO->getSubExpr(), MaxWidth);
6434    }
6435  }
6436
6437  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E))
6438    return GetExprRange(C, OVE->getSourceExpr(), MaxWidth);
6439
6440  if (FieldDecl *BitField = E->getSourceBitField())
6441    return IntRange(BitField->getBitWidthValue(C),
6442                    BitField->getType()->isUnsignedIntegerOrEnumerationType());
6443
6444  return IntRange::forValueOfType(C, GetExprType(E));
6445}
6446
6447static IntRange GetExprRange(ASTContext &C, Expr *E) {
6448  return GetExprRange(C, E, C.getIntWidth(GetExprType(E)));
6449}
6450
6451/// Checks whether the given value, which currently has the given
6452/// source semantics, has the same value when coerced through the
6453/// target semantics.
6454static bool IsSameFloatAfterCast(const llvm::APFloat &value,
6455                                 const llvm::fltSemantics &Src,
6456                                 const llvm::fltSemantics &Tgt) {
6457  llvm::APFloat truncated = value;
6458
6459  bool ignored;
6460  truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
6461  truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
6462
6463  return truncated.bitwiseIsEqual(value);
6464}
6465
6466/// Checks whether the given value, which currently has the given
6467/// source semantics, has the same value when coerced through the
6468/// target semantics.
6469///
6470/// The value might be a vector of floats (or a complex number).
6471static bool IsSameFloatAfterCast(const APValue &value,
6472                                 const llvm::fltSemantics &Src,
6473                                 const llvm::fltSemantics &Tgt) {
6474  if (value.isFloat())
6475    return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
6476
6477  if (value.isVector()) {
6478    for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
6479      if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
6480        return false;
6481    return true;
6482  }
6483
6484  assert(value.isComplexFloat());
6485  return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
6486          IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
6487}
6488
6489static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
6490
6491static bool IsZero(Sema &S, Expr *E) {
6492  // Suppress cases where we are comparing against an enum constant.
6493  if (const DeclRefExpr *DR =
6494      dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
6495    if (isa<EnumConstantDecl>(DR->getDecl()))
6496      return false;
6497
6498  // Suppress cases where the '0' value is expanded from a macro.
6499  if (E->getLocStart().isMacroID())
6500    return false;
6501
6502  llvm::APSInt Value;
6503  return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
6504}
6505
6506static bool HasEnumType(Expr *E) {
6507  // Strip off implicit integral promotions.
6508  while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
6509    if (ICE->getCastKind() != CK_IntegralCast &&
6510        ICE->getCastKind() != CK_NoOp)
6511      break;
6512    E = ICE->getSubExpr();
6513  }
6514
6515  return E->getType()->isEnumeralType();
6516}
6517
6518static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
6519  // Disable warning in template instantiations.
6520  if (!S.ActiveTemplateInstantiations.empty())
6521    return;
6522
6523  BinaryOperatorKind op = E->getOpcode();
6524  if (E->isValueDependent())
6525    return;
6526
6527  if (op == BO_LT && IsZero(S, E->getRHS())) {
6528    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
6529      << "< 0" << "false" << HasEnumType(E->getLHS())
6530      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
6531  } else if (op == BO_GE && IsZero(S, E->getRHS())) {
6532    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
6533      << ">= 0" << "true" << HasEnumType(E->getLHS())
6534      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
6535  } else if (op == BO_GT && IsZero(S, E->getLHS())) {
6536    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
6537      << "0 >" << "false" << HasEnumType(E->getRHS())
6538      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
6539  } else if (op == BO_LE && IsZero(S, E->getLHS())) {
6540    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
6541      << "0 <=" << "true" << HasEnumType(E->getRHS())
6542      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
6543  }
6544}
6545
6546static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E,
6547                                         Expr *Constant, Expr *Other,
6548                                         llvm::APSInt Value,
6549                                         bool RhsConstant) {
6550  // Disable warning in template instantiations.
6551  if (!S.ActiveTemplateInstantiations.empty())
6552    return;
6553
6554  // TODO: Investigate using GetExprRange() to get tighter bounds
6555  // on the bit ranges.
6556  QualType OtherT = Other->getType();
6557  if (const auto *AT = OtherT->getAs<AtomicType>())
6558    OtherT = AT->getValueType();
6559  IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
6560  unsigned OtherWidth = OtherRange.Width;
6561
6562  bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue();
6563
6564  // 0 values are handled later by CheckTrivialUnsignedComparison().
6565  if ((Value == 0) && (!OtherIsBooleanType))
6566    return;
6567
6568  BinaryOperatorKind op = E->getOpcode();
6569  bool IsTrue = true;
6570
6571  // Used for diagnostic printout.
6572  enum {
6573    LiteralConstant = 0,
6574    CXXBoolLiteralTrue,
6575    CXXBoolLiteralFalse
6576  } LiteralOrBoolConstant = LiteralConstant;
6577
6578  if (!OtherIsBooleanType) {
6579    QualType ConstantT = Constant->getType();
6580    QualType CommonT = E->getLHS()->getType();
6581
6582    if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT))
6583      return;
6584    assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) &&
6585           "comparison with non-integer type");
6586
6587    bool ConstantSigned = ConstantT->isSignedIntegerType();
6588    bool CommonSigned = CommonT->isSignedIntegerType();
6589
6590    bool EqualityOnly = false;
6591
6592    if (CommonSigned) {
6593      // The common type is signed, therefore no signed to unsigned conversion.
6594      if (!OtherRange.NonNegative) {
6595        // Check that the constant is representable in type OtherT.
6596        if (ConstantSigned) {
6597          if (OtherWidth >= Value.getMinSignedBits())
6598            return;
6599        } else { // !ConstantSigned
6600          if (OtherWidth >= Value.getActiveBits() + 1)
6601            return;
6602        }
6603      } else { // !OtherSigned
6604               // Check that the constant is representable in type OtherT.
6605        // Negative values are out of range.
6606        if (ConstantSigned) {
6607          if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits())
6608            return;
6609        } else { // !ConstantSigned
6610          if (OtherWidth >= Value.getActiveBits())
6611            return;
6612        }
6613      }
6614    } else { // !CommonSigned
6615      if (OtherRange.NonNegative) {
6616        if (OtherWidth >= Value.getActiveBits())
6617          return;
6618      } else { // OtherSigned
6619        assert(!ConstantSigned &&
6620               "Two signed types converted to unsigned types.");
6621        // Check to see if the constant is representable in OtherT.
6622        if (OtherWidth > Value.getActiveBits())
6623          return;
6624        // Check to see if the constant is equivalent to a negative value
6625        // cast to CommonT.
6626        if (S.Context.getIntWidth(ConstantT) ==
6627                S.Context.getIntWidth(CommonT) &&
6628            Value.isNegative() && Value.getMinSignedBits() <= OtherWidth)
6629          return;
6630        // The constant value rests between values that OtherT can represent
6631        // after conversion.  Relational comparison still works, but equality
6632        // comparisons will be tautological.
6633        EqualityOnly = true;
6634      }
6635    }
6636
6637    bool PositiveConstant = !ConstantSigned || Value.isNonNegative();
6638
6639    if (op == BO_EQ || op == BO_NE) {
6640      IsTrue = op == BO_NE;
6641    } else if (EqualityOnly) {
6642      return;
6643    } else if (RhsConstant) {
6644      if (op == BO_GT || op == BO_GE)
6645        IsTrue = !PositiveConstant;
6646      else // op == BO_LT || op == BO_LE
6647        IsTrue = PositiveConstant;
6648    } else {
6649      if (op == BO_LT || op == BO_LE)
6650        IsTrue = !PositiveConstant;
6651      else // op == BO_GT || op == BO_GE
6652        IsTrue = PositiveConstant;
6653    }
6654  } else {
6655    // Other isKnownToHaveBooleanValue
6656    enum CompareBoolWithConstantResult { AFals, ATrue, Unkwn };
6657    enum ConstantValue { LT_Zero, Zero, One, GT_One, SizeOfConstVal };
6658    enum ConstantSide { Lhs, Rhs, SizeOfConstSides };
6659
6660    static const struct LinkedConditions {
6661      CompareBoolWithConstantResult BO_LT_OP[SizeOfConstSides][SizeOfConstVal];
6662      CompareBoolWithConstantResult BO_GT_OP[SizeOfConstSides][SizeOfConstVal];
6663      CompareBoolWithConstantResult BO_LE_OP[SizeOfConstSides][SizeOfConstVal];
6664      CompareBoolWithConstantResult BO_GE_OP[SizeOfConstSides][SizeOfConstVal];
6665      CompareBoolWithConstantResult BO_EQ_OP[SizeOfConstSides][SizeOfConstVal];
6666      CompareBoolWithConstantResult BO_NE_OP[SizeOfConstSides][SizeOfConstVal];
6667
6668    } TruthTable = {
6669        // Constant on LHS.              | Constant on RHS.              |
6670        // LT_Zero| Zero  | One   |GT_One| LT_Zero| Zero  | One   |GT_One|
6671        { { ATrue, Unkwn, AFals, AFals }, { AFals, AFals, Unkwn, ATrue } },
6672        { { AFals, AFals, Unkwn, ATrue }, { ATrue, Unkwn, AFals, AFals } },
6673        { { ATrue, ATrue, Unkwn, AFals }, { AFals, Unkwn, ATrue, ATrue } },
6674        { { AFals, Unkwn, ATrue, ATrue }, { ATrue, ATrue, Unkwn, AFals } },
6675        { { AFals, Unkwn, Unkwn, AFals }, { AFals, Unkwn, Unkwn, AFals } },
6676        { { ATrue, Unkwn, Unkwn, ATrue }, { ATrue, Unkwn, Unkwn, ATrue } }
6677      };
6678
6679    bool ConstantIsBoolLiteral = isa<CXXBoolLiteralExpr>(Constant);
6680
6681    enum ConstantValue ConstVal = Zero;
6682    if (Value.isUnsigned() || Value.isNonNegative()) {
6683      if (Value == 0) {
6684        LiteralOrBoolConstant =
6685            ConstantIsBoolLiteral ? CXXBoolLiteralFalse : LiteralConstant;
6686        ConstVal = Zero;
6687      } else if (Value == 1) {
6688        LiteralOrBoolConstant =
6689            ConstantIsBoolLiteral ? CXXBoolLiteralTrue : LiteralConstant;
6690        ConstVal = One;
6691      } else {
6692        LiteralOrBoolConstant = LiteralConstant;
6693        ConstVal = GT_One;
6694      }
6695    } else {
6696      ConstVal = LT_Zero;
6697    }
6698
6699    CompareBoolWithConstantResult CmpRes;
6700
6701    switch (op) {
6702    case BO_LT:
6703      CmpRes = TruthTable.BO_LT_OP[RhsConstant][ConstVal];
6704      break;
6705    case BO_GT:
6706      CmpRes = TruthTable.BO_GT_OP[RhsConstant][ConstVal];
6707      break;
6708    case BO_LE:
6709      CmpRes = TruthTable.BO_LE_OP[RhsConstant][ConstVal];
6710      break;
6711    case BO_GE:
6712      CmpRes = TruthTable.BO_GE_OP[RhsConstant][ConstVal];
6713      break;
6714    case BO_EQ:
6715      CmpRes = TruthTable.BO_EQ_OP[RhsConstant][ConstVal];
6716      break;
6717    case BO_NE:
6718      CmpRes = TruthTable.BO_NE_OP[RhsConstant][ConstVal];
6719      break;
6720    default:
6721      CmpRes = Unkwn;
6722      break;
6723    }
6724
6725    if (CmpRes == AFals) {
6726      IsTrue = false;
6727    } else if (CmpRes == ATrue) {
6728      IsTrue = true;
6729    } else {
6730      return;
6731    }
6732  }
6733
6734  // If this is a comparison to an enum constant, include that
6735  // constant in the diagnostic.
6736  const EnumConstantDecl *ED = nullptr;
6737  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant))
6738    ED = dyn_cast<EnumConstantDecl>(DR->getDecl());
6739
6740  SmallString<64> PrettySourceValue;
6741  llvm::raw_svector_ostream OS(PrettySourceValue);
6742  if (ED)
6743    OS << '\'' << *ED << "' (" << Value << ")";
6744  else
6745    OS << Value;
6746
6747  S.DiagRuntimeBehavior(
6748    E->getOperatorLoc(), E,
6749    S.PDiag(diag::warn_out_of_range_compare)
6750        << OS.str() << LiteralOrBoolConstant
6751        << OtherT << (OtherIsBooleanType && !OtherT->isBooleanType()) << IsTrue
6752        << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange());
6753}
6754
6755/// Analyze the operands of the given comparison.  Implements the
6756/// fallback case from AnalyzeComparison.
6757static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
6758  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
6759  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
6760}
6761
6762/// \brief Implements -Wsign-compare.
6763///
6764/// \param E the binary operator to check for warnings
6765static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
6766  // The type the comparison is being performed in.
6767  QualType T = E->getLHS()->getType();
6768
6769  // Only analyze comparison operators where both sides have been converted to
6770  // the same type.
6771  if (!S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()))
6772    return AnalyzeImpConvsInComparison(S, E);
6773
6774  // Don't analyze value-dependent comparisons directly.
6775  if (E->isValueDependent())
6776    return AnalyzeImpConvsInComparison(S, E);
6777
6778  Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
6779  Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
6780
6781  bool IsComparisonConstant = false;
6782
6783  // Check whether an integer constant comparison results in a value
6784  // of 'true' or 'false'.
6785  if (T->isIntegralType(S.Context)) {
6786    llvm::APSInt RHSValue;
6787    bool IsRHSIntegralLiteral =
6788      RHS->isIntegerConstantExpr(RHSValue, S.Context);
6789    llvm::APSInt LHSValue;
6790    bool IsLHSIntegralLiteral =
6791      LHS->isIntegerConstantExpr(LHSValue, S.Context);
6792    if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral)
6793        DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true);
6794    else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral)
6795      DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false);
6796    else
6797      IsComparisonConstant =
6798        (IsRHSIntegralLiteral && IsLHSIntegralLiteral);
6799  } else if (!T->hasUnsignedIntegerRepresentation())
6800      IsComparisonConstant = E->isIntegerConstantExpr(S.Context);
6801
6802  // We don't do anything special if this isn't an unsigned integral
6803  // comparison:  we're only interested in integral comparisons, and
6804  // signed comparisons only happen in cases we don't care to warn about.
6805  //
6806  // We also don't care about value-dependent expressions or expressions
6807  // whose result is a constant.
6808  if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant)
6809    return AnalyzeImpConvsInComparison(S, E);
6810
6811  // Check to see if one of the (unmodified) operands is of different
6812  // signedness.
6813  Expr *signedOperand, *unsignedOperand;
6814  if (LHS->getType()->hasSignedIntegerRepresentation()) {
6815    assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
6816           "unsigned comparison between two signed integer expressions?");
6817    signedOperand = LHS;
6818    unsignedOperand = RHS;
6819  } else if (RHS->getType()->hasSignedIntegerRepresentation()) {
6820    signedOperand = RHS;
6821    unsignedOperand = LHS;
6822  } else {
6823    CheckTrivialUnsignedComparison(S, E);
6824    return AnalyzeImpConvsInComparison(S, E);
6825  }
6826
6827  // Otherwise, calculate the effective range of the signed operand.
6828  IntRange signedRange = GetExprRange(S.Context, signedOperand);
6829
6830  // Go ahead and analyze implicit conversions in the operands.  Note
6831  // that we skip the implicit conversions on both sides.
6832  AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
6833  AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
6834
6835  // If the signed range is non-negative, -Wsign-compare won't fire,
6836  // but we should still check for comparisons which are always true
6837  // or false.
6838  if (signedRange.NonNegative)
6839    return CheckTrivialUnsignedComparison(S, E);
6840
6841  // For (in)equality comparisons, if the unsigned operand is a
6842  // constant which cannot collide with a overflowed signed operand,
6843  // then reinterpreting the signed operand as unsigned will not
6844  // change the result of the comparison.
6845  if (E->isEqualityOp()) {
6846    unsigned comparisonWidth = S.Context.getIntWidth(T);
6847    IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
6848
6849    // We should never be unable to prove that the unsigned operand is
6850    // non-negative.
6851    assert(unsignedRange.NonNegative && "unsigned range includes negative?");
6852
6853    if (unsignedRange.Width < comparisonWidth)
6854      return;
6855  }
6856
6857  S.DiagRuntimeBehavior(E->getOperatorLoc(), E,
6858    S.PDiag(diag::warn_mixed_sign_comparison)
6859      << LHS->getType() << RHS->getType()
6860      << LHS->getSourceRange() << RHS->getSourceRange());
6861}
6862
6863/// Analyzes an attempt to assign the given value to a bitfield.
6864///
6865/// Returns true if there was something fishy about the attempt.
6866static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
6867                                      SourceLocation InitLoc) {
6868  assert(Bitfield->isBitField());
6869  if (Bitfield->isInvalidDecl())
6870    return false;
6871
6872  // White-list bool bitfields.
6873  if (Bitfield->getType()->isBooleanType())
6874    return false;
6875
6876  // Ignore value- or type-dependent expressions.
6877  if (Bitfield->getBitWidth()->isValueDependent() ||
6878      Bitfield->getBitWidth()->isTypeDependent() ||
6879      Init->isValueDependent() ||
6880      Init->isTypeDependent())
6881    return false;
6882
6883  Expr *OriginalInit = Init->IgnoreParenImpCasts();
6884
6885  llvm::APSInt Value;
6886  if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
6887    return false;
6888
6889  unsigned OriginalWidth = Value.getBitWidth();
6890  unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
6891
6892  if (OriginalWidth <= FieldWidth)
6893    return false;
6894
6895  // Compute the value which the bitfield will contain.
6896  llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
6897  TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
6898
6899  // Check whether the stored value is equal to the original value.
6900  TruncatedValue = TruncatedValue.extend(OriginalWidth);
6901  if (llvm::APSInt::isSameValue(Value, TruncatedValue))
6902    return false;
6903
6904  // Special-case bitfields of width 1: booleans are naturally 0/1, and
6905  // therefore don't strictly fit into a signed bitfield of width 1.
6906  if (FieldWidth == 1 && Value == 1)
6907    return false;
6908
6909  std::string PrettyValue = Value.toString(10);
6910  std::string PrettyTrunc = TruncatedValue.toString(10);
6911
6912  S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
6913    << PrettyValue << PrettyTrunc << OriginalInit->getType()
6914    << Init->getSourceRange();
6915
6916  return true;
6917}
6918
6919/// Analyze the given simple or compound assignment for warning-worthy
6920/// operations.
6921static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
6922  // Just recurse on the LHS.
6923  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
6924
6925  // We want to recurse on the RHS as normal unless we're assigning to
6926  // a bitfield.
6927  if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) {
6928    if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
6929                                  E->getOperatorLoc())) {
6930      // Recurse, ignoring any implicit conversions on the RHS.
6931      return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
6932                                        E->getOperatorLoc());
6933    }
6934  }
6935
6936  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
6937}
6938
6939/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
6940static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
6941                            SourceLocation CContext, unsigned diag,
6942                            bool pruneControlFlow = false) {
6943  if (pruneControlFlow) {
6944    S.DiagRuntimeBehavior(E->getExprLoc(), E,
6945                          S.PDiag(diag)
6946                            << SourceType << T << E->getSourceRange()
6947                            << SourceRange(CContext));
6948    return;
6949  }
6950  S.Diag(E->getExprLoc(), diag)
6951    << SourceType << T << E->getSourceRange() << SourceRange(CContext);
6952}
6953
6954/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
6955static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
6956                            SourceLocation CContext, unsigned diag,
6957                            bool pruneControlFlow = false) {
6958  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
6959}
6960
6961/// Diagnose an implicit cast from a literal expression. Does not warn when the
6962/// cast wouldn't lose information.
6963void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T,
6964                                    SourceLocation CContext) {
6965  // Try to convert the literal exactly to an integer. If we can, don't warn.
6966  bool isExact = false;
6967  const llvm::APFloat &Value = FL->getValue();
6968  llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
6969                            T->hasUnsignedIntegerRepresentation());
6970  if (Value.convertToInteger(IntegerValue,
6971                             llvm::APFloat::rmTowardZero, &isExact)
6972      == llvm::APFloat::opOK && isExact)
6973    return;
6974
6975  // FIXME: Force the precision of the source value down so we don't print
6976  // digits which are usually useless (we don't really care here if we
6977  // truncate a digit by accident in edge cases).  Ideally, APFloat::toString
6978  // would automatically print the shortest representation, but it's a bit
6979  // tricky to implement.
6980  SmallString<16> PrettySourceValue;
6981  unsigned precision = llvm::APFloat::semanticsPrecision(Value.getSemantics());
6982  precision = (precision * 59 + 195) / 196;
6983  Value.toString(PrettySourceValue, precision);
6984
6985  SmallString<16> PrettyTargetValue;
6986  if (T->isSpecificBuiltinType(BuiltinType::Bool))
6987    PrettyTargetValue = Value.isZero() ? "false" : "true";
6988  else
6989    IntegerValue.toString(PrettyTargetValue);
6990
6991  S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer)
6992    << FL->getType() << T.getUnqualifiedType() << PrettySourceValue
6993    << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext);
6994}
6995
6996std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
6997  if (!Range.Width) return "0";
6998
6999  llvm::APSInt ValueInRange = Value;
7000  ValueInRange.setIsSigned(!Range.NonNegative);
7001  ValueInRange = ValueInRange.trunc(Range.Width);
7002  return ValueInRange.toString(10);
7003}
7004
7005static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) {
7006  if (!isa<ImplicitCastExpr>(Ex))
7007    return false;
7008
7009  Expr *InnerE = Ex->IgnoreParenImpCasts();
7010  const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr();
7011  const Type *Source =
7012    S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
7013  if (Target->isDependentType())
7014    return false;
7015
7016  const BuiltinType *FloatCandidateBT =
7017    dyn_cast<BuiltinType>(ToBool ? Source : Target);
7018  const Type *BoolCandidateType = ToBool ? Target : Source;
7019
7020  return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) &&
7021          FloatCandidateBT && (FloatCandidateBT->isFloatingPoint()));
7022}
7023
7024void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall,
7025                                      SourceLocation CC) {
7026  unsigned NumArgs = TheCall->getNumArgs();
7027  for (unsigned i = 0; i < NumArgs; ++i) {
7028    Expr *CurrA = TheCall->getArg(i);
7029    if (!IsImplicitBoolFloatConversion(S, CurrA, true))
7030      continue;
7031
7032    bool IsSwapped = ((i > 0) &&
7033        IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false));
7034    IsSwapped |= ((i < (NumArgs - 1)) &&
7035        IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false));
7036    if (IsSwapped) {
7037      // Warn on this floating-point to bool conversion.
7038      DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(),
7039                      CurrA->getType(), CC,
7040                      diag::warn_impcast_floating_point_to_bool);
7041    }
7042  }
7043}
7044
7045static void DiagnoseNullConversion(Sema &S, Expr *E, QualType T,
7046                                   SourceLocation CC) {
7047  if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer,
7048                        E->getExprLoc()))
7049    return;
7050
7051  // Don't warn on functions which have return type nullptr_t.
7052  if (isa<CallExpr>(E))
7053    return;
7054
7055  // Check for NULL (GNUNull) or nullptr (CXX11_nullptr).
7056  const Expr::NullPointerConstantKind NullKind =
7057      E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull);
7058  if (NullKind != Expr::NPCK_GNUNull && NullKind != Expr::NPCK_CXX11_nullptr)
7059    return;
7060
7061  // Return if target type is a safe conversion.
7062  if (T->isAnyPointerType() || T->isBlockPointerType() ||
7063      T->isMemberPointerType() || !T->isScalarType() || T->isNullPtrType())
7064    return;
7065
7066  SourceLocation Loc = E->getSourceRange().getBegin();
7067
7068  // __null is usually wrapped in a macro.  Go up a macro if that is the case.
7069  if (NullKind == Expr::NPCK_GNUNull) {
7070    if (Loc.isMacroID()) {
7071      StringRef MacroName =
7072          Lexer::getImmediateMacroName(Loc, S.SourceMgr, S.getLangOpts());
7073      if (MacroName == "NULL")
7074        Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first;
7075    }
7076  }
7077
7078  // Only warn if the null and context location are in the same macro expansion.
7079  if (S.SourceMgr.getFileID(Loc) != S.SourceMgr.getFileID(CC))
7080    return;
7081
7082  S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer)
7083      << (NullKind == Expr::NPCK_CXX11_nullptr) << T << clang::SourceRange(CC)
7084      << FixItHint::CreateReplacement(Loc,
7085                                      S.getFixItZeroLiteralForType(T, Loc));
7086}
7087
7088static void checkObjCArrayLiteral(Sema &S, QualType TargetType,
7089                                  ObjCArrayLiteral *ArrayLiteral);
7090static void checkObjCDictionaryLiteral(Sema &S, QualType TargetType,
7091                                       ObjCDictionaryLiteral *DictionaryLiteral);
7092
7093/// Check a single element within a collection literal against the
7094/// target element type.
7095static void checkObjCCollectionLiteralElement(Sema &S,
7096                                              QualType TargetElementType,
7097                                              Expr *Element,
7098                                              unsigned ElementKind) {
7099  // Skip a bitcast to 'id' or qualified 'id'.
7100  if (auto ICE = dyn_cast<ImplicitCastExpr>(Element)) {
7101    if (ICE->getCastKind() == CK_BitCast &&
7102        ICE->getSubExpr()->getType()->getAs<ObjCObjectPointerType>())
7103      Element = ICE->getSubExpr();
7104  }
7105
7106  QualType ElementType = Element->getType();
7107  ExprResult ElementResult(Element);
7108  if (ElementType->getAs<ObjCObjectPointerType>() &&
7109      S.CheckSingleAssignmentConstraints(TargetElementType,
7110                                         ElementResult,
7111                                         false, false)
7112        != Sema::Compatible) {
7113    S.Diag(Element->getLocStart(),
7114           diag::warn_objc_collection_literal_element)
7115      << ElementType << ElementKind << TargetElementType
7116      << Element->getSourceRange();
7117  }
7118
7119  if (auto ArrayLiteral = dyn_cast<ObjCArrayLiteral>(Element))
7120    checkObjCArrayLiteral(S, TargetElementType, ArrayLiteral);
7121  else if (auto DictionaryLiteral = dyn_cast<ObjCDictionaryLiteral>(Element))
7122    checkObjCDictionaryLiteral(S, TargetElementType, DictionaryLiteral);
7123}
7124
7125/// Check an Objective-C array literal being converted to the given
7126/// target type.
7127static void checkObjCArrayLiteral(Sema &S, QualType TargetType,
7128                                  ObjCArrayLiteral *ArrayLiteral) {
7129  if (!S.NSArrayDecl)
7130    return;
7131
7132  const auto *TargetObjCPtr = TargetType->getAs<ObjCObjectPointerType>();
7133  if (!TargetObjCPtr)
7134    return;
7135
7136  if (TargetObjCPtr->isUnspecialized() ||
7137      TargetObjCPtr->getInterfaceDecl()->getCanonicalDecl()
7138        != S.NSArrayDecl->getCanonicalDecl())
7139    return;
7140
7141  auto TypeArgs = TargetObjCPtr->getTypeArgs();
7142  if (TypeArgs.size() != 1)
7143    return;
7144
7145  QualType TargetElementType = TypeArgs[0];
7146  for (unsigned I = 0, N = ArrayLiteral->getNumElements(); I != N; ++I) {
7147    checkObjCCollectionLiteralElement(S, TargetElementType,
7148                                      ArrayLiteral->getElement(I),
7149                                      0);
7150  }
7151}
7152
7153/// Check an Objective-C dictionary literal being converted to the given
7154/// target type.
7155static void checkObjCDictionaryLiteral(
7156              Sema &S, QualType TargetType,
7157              ObjCDictionaryLiteral *DictionaryLiteral) {
7158  if (!S.NSDictionaryDecl)
7159    return;
7160
7161  const auto *TargetObjCPtr = TargetType->getAs<ObjCObjectPointerType>();
7162  if (!TargetObjCPtr)
7163    return;
7164
7165  if (TargetObjCPtr->isUnspecialized() ||
7166      TargetObjCPtr->getInterfaceDecl()->getCanonicalDecl()
7167        != S.NSDictionaryDecl->getCanonicalDecl())
7168    return;
7169
7170  auto TypeArgs = TargetObjCPtr->getTypeArgs();
7171  if (TypeArgs.size() != 2)
7172    return;
7173
7174  QualType TargetKeyType = TypeArgs[0];
7175  QualType TargetObjectType = TypeArgs[1];
7176  for (unsigned I = 0, N = DictionaryLiteral->getNumElements(); I != N; ++I) {
7177    auto Element = DictionaryLiteral->getKeyValueElement(I);
7178    checkObjCCollectionLiteralElement(S, TargetKeyType, Element.Key, 1);
7179    checkObjCCollectionLiteralElement(S, TargetObjectType, Element.Value, 2);
7180  }
7181}
7182
7183void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
7184                             SourceLocation CC, bool *ICContext = nullptr) {
7185  if (E->isTypeDependent() || E->isValueDependent()) return;
7186
7187  const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
7188  const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
7189  if (Source == Target) return;
7190  if (Target->isDependentType()) return;
7191
7192  // If the conversion context location is invalid don't complain. We also
7193  // don't want to emit a warning if the issue occurs from the expansion of
7194  // a system macro. The problem is that 'getSpellingLoc()' is slow, so we
7195  // delay this check as long as possible. Once we detect we are in that
7196  // scenario, we just return.
7197  if (CC.isInvalid())
7198    return;
7199
7200  // Diagnose implicit casts to bool.
7201  if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
7202    if (isa<StringLiteral>(E))
7203      // Warn on string literal to bool.  Checks for string literals in logical
7204      // and expressions, for instance, assert(0 && "error here"), are
7205      // prevented by a check in AnalyzeImplicitConversions().
7206      return DiagnoseImpCast(S, E, T, CC,
7207                             diag::warn_impcast_string_literal_to_bool);
7208    if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) ||
7209        isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) {
7210      // This covers the literal expressions that evaluate to Objective-C
7211      // objects.
7212      return DiagnoseImpCast(S, E, T, CC,
7213                             diag::warn_impcast_objective_c_literal_to_bool);
7214    }
7215    if (Source->isPointerType() || Source->canDecayToPointerType()) {
7216      // Warn on pointer to bool conversion that is always true.
7217      S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false,
7218                                     SourceRange(CC));
7219    }
7220  }
7221
7222  // Check implicit casts from Objective-C collection literals to specialized
7223  // collection types, e.g., NSArray<NSString *> *.
7224  if (auto *ArrayLiteral = dyn_cast<ObjCArrayLiteral>(E))
7225    checkObjCArrayLiteral(S, QualType(Target, 0), ArrayLiteral);
7226  else if (auto *DictionaryLiteral = dyn_cast<ObjCDictionaryLiteral>(E))
7227    checkObjCDictionaryLiteral(S, QualType(Target, 0), DictionaryLiteral);
7228
7229  // Strip vector types.
7230  if (isa<VectorType>(Source)) {
7231    if (!isa<VectorType>(Target)) {
7232      if (S.SourceMgr.isInSystemMacro(CC))
7233        return;
7234      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
7235    }
7236
7237    // If the vector cast is cast between two vectors of the same size, it is
7238    // a bitcast, not a conversion.
7239    if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
7240      return;
7241
7242    Source = cast<VectorType>(Source)->getElementType().getTypePtr();
7243    Target = cast<VectorType>(Target)->getElementType().getTypePtr();
7244  }
7245  if (auto VecTy = dyn_cast<VectorType>(Target))
7246    Target = VecTy->getElementType().getTypePtr();
7247
7248  // Strip complex types.
7249  if (isa<ComplexType>(Source)) {
7250    if (!isa<ComplexType>(Target)) {
7251      if (S.SourceMgr.isInSystemMacro(CC))
7252        return;
7253
7254      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
7255    }
7256
7257    Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
7258    Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
7259  }
7260
7261  const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
7262  const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
7263
7264  // If the source is floating point...
7265  if (SourceBT && SourceBT->isFloatingPoint()) {
7266    // ...and the target is floating point...
7267    if (TargetBT && TargetBT->isFloatingPoint()) {
7268      // ...then warn if we're dropping FP rank.
7269
7270      // Builtin FP kinds are ordered by increasing FP rank.
7271      if (SourceBT->getKind() > TargetBT->getKind()) {
7272        // Don't warn about float constants that are precisely
7273        // representable in the target type.
7274        Expr::EvalResult result;
7275        if (E->EvaluateAsRValue(result, S.Context)) {
7276          // Value might be a float, a float vector, or a float complex.
7277          if (IsSameFloatAfterCast(result.Val,
7278                   S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
7279                   S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
7280            return;
7281        }
7282
7283        if (S.SourceMgr.isInSystemMacro(CC))
7284          return;
7285
7286        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
7287
7288      }
7289      // ... or possibly if we're increasing rank, too
7290      else if (TargetBT->getKind() > SourceBT->getKind()) {
7291        if (S.SourceMgr.isInSystemMacro(CC))
7292          return;
7293
7294        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_double_promotion);
7295      }
7296      return;
7297    }
7298
7299    // If the target is integral, always warn.
7300    if (TargetBT && TargetBT->isInteger()) {
7301      if (S.SourceMgr.isInSystemMacro(CC))
7302        return;
7303
7304      Expr *InnerE = E->IgnoreParenImpCasts();
7305      // We also want to warn on, e.g., "int i = -1.234"
7306      if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
7307        if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
7308          InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
7309
7310      if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) {
7311        DiagnoseFloatingLiteralImpCast(S, FL, T, CC);
7312      } else {
7313        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
7314      }
7315    }
7316
7317    // Detect the case where a call result is converted from floating-point to
7318    // to bool, and the final argument to the call is converted from bool, to
7319    // discover this typo:
7320    //
7321    //    bool b = fabs(x < 1.0);  // should be "bool b = fabs(x) < 1.0;"
7322    //
7323    // FIXME: This is an incredibly special case; is there some more general
7324    // way to detect this class of misplaced-parentheses bug?
7325    if (Target->isBooleanType() && isa<CallExpr>(E)) {
7326      // Check last argument of function call to see if it is an
7327      // implicit cast from a type matching the type the result
7328      // is being cast to.
7329      CallExpr *CEx = cast<CallExpr>(E);
7330      if (unsigned NumArgs = CEx->getNumArgs()) {
7331        Expr *LastA = CEx->getArg(NumArgs - 1);
7332        Expr *InnerE = LastA->IgnoreParenImpCasts();
7333        if (isa<ImplicitCastExpr>(LastA) &&
7334            InnerE->getType()->isBooleanType()) {
7335          // Warn on this floating-point to bool conversion
7336          DiagnoseImpCast(S, E, T, CC,
7337                          diag::warn_impcast_floating_point_to_bool);
7338        }
7339      }
7340    }
7341    return;
7342  }
7343
7344  DiagnoseNullConversion(S, E, T, CC);
7345
7346  if (!Source->isIntegerType() || !Target->isIntegerType())
7347    return;
7348
7349  // TODO: remove this early return once the false positives for constant->bool
7350  // in templates, macros, etc, are reduced or removed.
7351  if (Target->isSpecificBuiltinType(BuiltinType::Bool))
7352    return;
7353
7354  IntRange SourceRange = GetExprRange(S.Context, E);
7355  IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
7356
7357  if (SourceRange.Width > TargetRange.Width) {
7358    // If the source is a constant, use a default-on diagnostic.
7359    // TODO: this should happen for bitfield stores, too.
7360    llvm::APSInt Value(32);
7361    if (E->isIntegerConstantExpr(Value, S.Context)) {
7362      if (S.SourceMgr.isInSystemMacro(CC))
7363        return;
7364
7365      std::string PrettySourceValue = Value.toString(10);
7366      std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
7367
7368      S.DiagRuntimeBehavior(E->getExprLoc(), E,
7369        S.PDiag(diag::warn_impcast_integer_precision_constant)
7370            << PrettySourceValue << PrettyTargetValue
7371            << E->getType() << T << E->getSourceRange()
7372            << clang::SourceRange(CC));
7373      return;
7374    }
7375
7376    // People want to build with -Wshorten-64-to-32 and not -Wconversion.
7377    if (S.SourceMgr.isInSystemMacro(CC))
7378      return;
7379
7380    if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64)
7381      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
7382                             /* pruneControlFlow */ true);
7383    return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
7384  }
7385
7386  if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
7387      (!TargetRange.NonNegative && SourceRange.NonNegative &&
7388       SourceRange.Width == TargetRange.Width)) {
7389
7390    if (S.SourceMgr.isInSystemMacro(CC))
7391      return;
7392
7393    unsigned DiagID = diag::warn_impcast_integer_sign;
7394
7395    // Traditionally, gcc has warned about this under -Wsign-compare.
7396    // We also want to warn about it in -Wconversion.
7397    // So if -Wconversion is off, use a completely identical diagnostic
7398    // in the sign-compare group.
7399    // The conditional-checking code will
7400    if (ICContext) {
7401      DiagID = diag::warn_impcast_integer_sign_conditional;
7402      *ICContext = true;
7403    }
7404
7405    return DiagnoseImpCast(S, E, T, CC, DiagID);
7406  }
7407
7408  // Diagnose conversions between different enumeration types.
7409  // In C, we pretend that the type of an EnumConstantDecl is its enumeration
7410  // type, to give us better diagnostics.
7411  QualType SourceType = E->getType();
7412  if (!S.getLangOpts().CPlusPlus) {
7413    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
7414      if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
7415        EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
7416        SourceType = S.Context.getTypeDeclType(Enum);
7417        Source = S.Context.getCanonicalType(SourceType).getTypePtr();
7418      }
7419  }
7420
7421  if (const EnumType *SourceEnum = Source->getAs<EnumType>())
7422    if (const EnumType *TargetEnum = Target->getAs<EnumType>())
7423      if (SourceEnum->getDecl()->hasNameForLinkage() &&
7424          TargetEnum->getDecl()->hasNameForLinkage() &&
7425          SourceEnum != TargetEnum) {
7426        if (S.SourceMgr.isInSystemMacro(CC))
7427          return;
7428
7429        return DiagnoseImpCast(S, E, SourceType, T, CC,
7430                               diag::warn_impcast_different_enum_types);
7431      }
7432
7433  return;
7434}
7435
7436void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
7437                              SourceLocation CC, QualType T);
7438
7439void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
7440                             SourceLocation CC, bool &ICContext) {
7441  E = E->IgnoreParenImpCasts();
7442
7443  if (isa<ConditionalOperator>(E))
7444    return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T);
7445
7446  AnalyzeImplicitConversions(S, E, CC);
7447  if (E->getType() != T)
7448    return CheckImplicitConversion(S, E, T, CC, &ICContext);
7449  return;
7450}
7451
7452void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
7453                              SourceLocation CC, QualType T) {
7454  AnalyzeImplicitConversions(S, E->getCond(), E->getQuestionLoc());
7455
7456  bool Suspicious = false;
7457  CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
7458  CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
7459
7460  // If -Wconversion would have warned about either of the candidates
7461  // for a signedness conversion to the context type...
7462  if (!Suspicious) return;
7463
7464  // ...but it's currently ignored...
7465  if (!S.Diags.isIgnored(diag::warn_impcast_integer_sign_conditional, CC))
7466    return;
7467
7468  // ...then check whether it would have warned about either of the
7469  // candidates for a signedness conversion to the condition type.
7470  if (E->getType() == T) return;
7471
7472  Suspicious = false;
7473  CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
7474                          E->getType(), CC, &Suspicious);
7475  if (!Suspicious)
7476    CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
7477                            E->getType(), CC, &Suspicious);
7478}
7479
7480/// CheckBoolLikeConversion - Check conversion of given expression to boolean.
7481/// Input argument E is a logical expression.
7482static void CheckBoolLikeConversion(Sema &S, Expr *E, SourceLocation CC) {
7483  if (S.getLangOpts().Bool)
7484    return;
7485  CheckImplicitConversion(S, E->IgnoreParenImpCasts(), S.Context.BoolTy, CC);
7486}
7487
7488/// AnalyzeImplicitConversions - Find and report any interesting
7489/// implicit conversions in the given expression.  There are a couple
7490/// of competing diagnostics here, -Wconversion and -Wsign-compare.
7491void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
7492  QualType T = OrigE->getType();
7493  Expr *E = OrigE->IgnoreParenImpCasts();
7494
7495  if (E->isTypeDependent() || E->isValueDependent())
7496    return;
7497
7498  // For conditional operators, we analyze the arguments as if they
7499  // were being fed directly into the output.
7500  if (isa<ConditionalOperator>(E)) {
7501    ConditionalOperator *CO = cast<ConditionalOperator>(E);
7502    CheckConditionalOperator(S, CO, CC, T);
7503    return;
7504  }
7505
7506  // Check implicit argument conversions for function calls.
7507  if (CallExpr *Call = dyn_cast<CallExpr>(E))
7508    CheckImplicitArgumentConversions(S, Call, CC);
7509
7510  // Go ahead and check any implicit conversions we might have skipped.
7511  // The non-canonical typecheck is just an optimization;
7512  // CheckImplicitConversion will filter out dead implicit conversions.
7513  if (E->getType() != T)
7514    CheckImplicitConversion(S, E, T, CC);
7515
7516  // Now continue drilling into this expression.
7517
7518  if (PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
7519    // The bound subexpressions in a PseudoObjectExpr are not reachable
7520    // as transitive children.
7521    // FIXME: Use a more uniform representation for this.
7522    for (auto *SE : POE->semantics())
7523      if (auto *OVE = dyn_cast<OpaqueValueExpr>(SE))
7524        AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC);
7525  }
7526
7527  // Skip past explicit casts.
7528  if (isa<ExplicitCastExpr>(E)) {
7529    E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
7530    return AnalyzeImplicitConversions(S, E, CC);
7531  }
7532
7533  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
7534    // Do a somewhat different check with comparison operators.
7535    if (BO->isComparisonOp())
7536      return AnalyzeComparison(S, BO);
7537
7538    // And with simple assignments.
7539    if (BO->getOpcode() == BO_Assign)
7540      return AnalyzeAssignment(S, BO);
7541  }
7542
7543  // These break the otherwise-useful invariant below.  Fortunately,
7544  // we don't really need to recurse into them, because any internal
7545  // expressions should have been analyzed already when they were
7546  // built into statements.
7547  if (isa<StmtExpr>(E)) return;
7548
7549  // Don't descend into unevaluated contexts.
7550  if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
7551
7552  // Now just recurse over the expression's children.
7553  CC = E->getExprLoc();
7554  BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
7555  bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd;
7556  for (Stmt *SubStmt : E->children()) {
7557    Expr *ChildExpr = dyn_cast_or_null<Expr>(SubStmt);
7558    if (!ChildExpr)
7559      continue;
7560
7561    if (IsLogicalAndOperator &&
7562        isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
7563      // Ignore checking string literals that are in logical and operators.
7564      // This is a common pattern for asserts.
7565      continue;
7566    AnalyzeImplicitConversions(S, ChildExpr, CC);
7567  }
7568
7569  if (BO && BO->isLogicalOp()) {
7570    Expr *SubExpr = BO->getLHS()->IgnoreParenImpCasts();
7571    if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr))
7572      ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc());
7573
7574    SubExpr = BO->getRHS()->IgnoreParenImpCasts();
7575    if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr))
7576      ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc());
7577  }
7578
7579  if (const UnaryOperator *U = dyn_cast<UnaryOperator>(E))
7580    if (U->getOpcode() == UO_LNot)
7581      ::CheckBoolLikeConversion(S, U->getSubExpr(), CC);
7582}
7583
7584} // end anonymous namespace
7585
7586// Helper function for Sema::DiagnoseAlwaysNonNullPointer.
7587// Returns true when emitting a warning about taking the address of a reference.
7588static bool CheckForReference(Sema &SemaRef, const Expr *E,
7589                              PartialDiagnostic PD) {
7590  E = E->IgnoreParenImpCasts();
7591
7592  const FunctionDecl *FD = nullptr;
7593
7594  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
7595    if (!DRE->getDecl()->getType()->isReferenceType())
7596      return false;
7597  } else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) {
7598    if (!M->getMemberDecl()->getType()->isReferenceType())
7599      return false;
7600  } else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) {
7601    if (!Call->getCallReturnType(SemaRef.Context)->isReferenceType())
7602      return false;
7603    FD = Call->getDirectCallee();
7604  } else {
7605    return false;
7606  }
7607
7608  SemaRef.Diag(E->getExprLoc(), PD);
7609
7610  // If possible, point to location of function.
7611  if (FD) {
7612    SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD;
7613  }
7614
7615  return true;
7616}
7617
7618// Returns true if the SourceLocation is expanded from any macro body.
7619// Returns false if the SourceLocation is invalid, is from not in a macro
7620// expansion, or is from expanded from a top-level macro argument.
7621static bool IsInAnyMacroBody(const SourceManager &SM, SourceLocation Loc) {
7622  if (Loc.isInvalid())
7623    return false;
7624
7625  while (Loc.isMacroID()) {
7626    if (SM.isMacroBodyExpansion(Loc))
7627      return true;
7628    Loc = SM.getImmediateMacroCallerLoc(Loc);
7629  }
7630
7631  return false;
7632}
7633
7634/// \brief Diagnose pointers that are always non-null.
7635/// \param E the expression containing the pointer
7636/// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is
7637/// compared to a null pointer
7638/// \param IsEqual True when the comparison is equal to a null pointer
7639/// \param Range Extra SourceRange to highlight in the diagnostic
7640void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
7641                                        Expr::NullPointerConstantKind NullKind,
7642                                        bool IsEqual, SourceRange Range) {
7643  if (!E)
7644    return;
7645
7646  // Don't warn inside macros.
7647  if (E->getExprLoc().isMacroID()) {
7648    const SourceManager &SM = getSourceManager();
7649    if (IsInAnyMacroBody(SM, E->getExprLoc()) ||
7650        IsInAnyMacroBody(SM, Range.getBegin()))
7651      return;
7652  }
7653  E = E->IgnoreImpCasts();
7654
7655  const bool IsCompare = NullKind != Expr::NPCK_NotNull;
7656
7657  if (isa<CXXThisExpr>(E)) {
7658    unsigned DiagID = IsCompare ? diag::warn_this_null_compare
7659                                : diag::warn_this_bool_conversion;
7660    Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual;
7661    return;
7662  }
7663
7664  bool IsAddressOf = false;
7665
7666  if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
7667    if (UO->getOpcode() != UO_AddrOf)
7668      return;
7669    IsAddressOf = true;
7670    E = UO->getSubExpr();
7671  }
7672
7673  if (IsAddressOf) {
7674    unsigned DiagID = IsCompare
7675                          ? diag::warn_address_of_reference_null_compare
7676                          : diag::warn_address_of_reference_bool_conversion;
7677    PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range
7678                                         << IsEqual;
7679    if (CheckForReference(*this, E, PD)) {
7680      return;
7681    }
7682  }
7683
7684  auto ComplainAboutNonnullParamOrCall = [&](bool IsParam) {
7685    std::string Str;
7686    llvm::raw_string_ostream S(Str);
7687    E->printPretty(S, nullptr, getPrintingPolicy());
7688    unsigned DiagID = IsCompare ? diag::warn_nonnull_expr_compare
7689                                : diag::warn_cast_nonnull_to_bool;
7690    Diag(E->getExprLoc(), DiagID) << IsParam << S.str()
7691      << E->getSourceRange() << Range << IsEqual;
7692  };
7693
7694  // If we have a CallExpr that is tagged with returns_nonnull, we can complain.
7695  if (auto *Call = dyn_cast<CallExpr>(E->IgnoreParenImpCasts())) {
7696    if (auto *Callee = Call->getDirectCallee()) {
7697      if (Callee->hasAttr<ReturnsNonNullAttr>()) {
7698        ComplainAboutNonnullParamOrCall(false);
7699        return;
7700      }
7701    }
7702  }
7703
7704  // Expect to find a single Decl.  Skip anything more complicated.
7705  ValueDecl *D = nullptr;
7706  if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) {
7707    D = R->getDecl();
7708  } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
7709    D = M->getMemberDecl();
7710  }
7711
7712  // Weak Decls can be null.
7713  if (!D || D->isWeak())
7714    return;
7715
7716  // Check for parameter decl with nonnull attribute
7717  if (const auto* PV = dyn_cast<ParmVarDecl>(D)) {
7718    if (getCurFunction() &&
7719        !getCurFunction()->ModifiedNonNullParams.count(PV)) {
7720      if (PV->hasAttr<NonNullAttr>()) {
7721        ComplainAboutNonnullParamOrCall(true);
7722        return;
7723      }
7724
7725      if (const auto *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) {
7726        auto ParamIter = std::find(FD->param_begin(), FD->param_end(), PV);
7727        assert(ParamIter != FD->param_end());
7728        unsigned ParamNo = std::distance(FD->param_begin(), ParamIter);
7729
7730        for (const auto *NonNull : FD->specific_attrs<NonNullAttr>()) {
7731          if (!NonNull->args_size()) {
7732              ComplainAboutNonnullParamOrCall(true);
7733              return;
7734          }
7735
7736          for (unsigned ArgNo : NonNull->args()) {
7737            if (ArgNo == ParamNo) {
7738              ComplainAboutNonnullParamOrCall(true);
7739              return;
7740            }
7741          }
7742        }
7743      }
7744    }
7745  }
7746
7747  QualType T = D->getType();
7748  const bool IsArray = T->isArrayType();
7749  const bool IsFunction = T->isFunctionType();
7750
7751  // Address of function is used to silence the function warning.
7752  if (IsAddressOf && IsFunction) {
7753    return;
7754  }
7755
7756  // Found nothing.
7757  if (!IsAddressOf && !IsFunction && !IsArray)
7758    return;
7759
7760  // Pretty print the expression for the diagnostic.
7761  std::string Str;
7762  llvm::raw_string_ostream S(Str);
7763  E->printPretty(S, nullptr, getPrintingPolicy());
7764
7765  unsigned DiagID = IsCompare ? diag::warn_null_pointer_compare
7766                              : diag::warn_impcast_pointer_to_bool;
7767  enum {
7768    AddressOf,
7769    FunctionPointer,
7770    ArrayPointer
7771  } DiagType;
7772  if (IsAddressOf)
7773    DiagType = AddressOf;
7774  else if (IsFunction)
7775    DiagType = FunctionPointer;
7776  else if (IsArray)
7777    DiagType = ArrayPointer;
7778  else
7779    llvm_unreachable("Could not determine diagnostic.");
7780  Diag(E->getExprLoc(), DiagID) << DiagType << S.str() << E->getSourceRange()
7781                                << Range << IsEqual;
7782
7783  if (!IsFunction)
7784    return;
7785
7786  // Suggest '&' to silence the function warning.
7787  Diag(E->getExprLoc(), diag::note_function_warning_silence)
7788      << FixItHint::CreateInsertion(E->getLocStart(), "&");
7789
7790  // Check to see if '()' fixit should be emitted.
7791  QualType ReturnType;
7792  UnresolvedSet<4> NonTemplateOverloads;
7793  tryExprAsCall(*E, ReturnType, NonTemplateOverloads);
7794  if (ReturnType.isNull())
7795    return;
7796
7797  if (IsCompare) {
7798    // There are two cases here.  If there is null constant, the only suggest
7799    // for a pointer return type.  If the null is 0, then suggest if the return
7800    // type is a pointer or an integer type.
7801    if (!ReturnType->isPointerType()) {
7802      if (NullKind == Expr::NPCK_ZeroExpression ||
7803          NullKind == Expr::NPCK_ZeroLiteral) {
7804        if (!ReturnType->isIntegerType())
7805          return;
7806      } else {
7807        return;
7808      }
7809    }
7810  } else { // !IsCompare
7811    // For function to bool, only suggest if the function pointer has bool
7812    // return type.
7813    if (!ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
7814      return;
7815  }
7816  Diag(E->getExprLoc(), diag::note_function_to_function_call)
7817      << FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()");
7818}
7819
7820
7821/// Diagnoses "dangerous" implicit conversions within the given
7822/// expression (which is a full expression).  Implements -Wconversion
7823/// and -Wsign-compare.
7824///
7825/// \param CC the "context" location of the implicit conversion, i.e.
7826///   the most location of the syntactic entity requiring the implicit
7827///   conversion
7828void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
7829  // Don't diagnose in unevaluated contexts.
7830  if (isUnevaluatedContext())
7831    return;
7832
7833  // Don't diagnose for value- or type-dependent expressions.
7834  if (E->isTypeDependent() || E->isValueDependent())
7835    return;
7836
7837  // Check for array bounds violations in cases where the check isn't triggered
7838  // elsewhere for other Expr types (like BinaryOperators), e.g. when an
7839  // ArraySubscriptExpr is on the RHS of a variable initialization.
7840  CheckArrayAccess(E);
7841
7842  // This is not the right CC for (e.g.) a variable initialization.
7843  AnalyzeImplicitConversions(*this, E, CC);
7844}
7845
7846/// CheckBoolLikeConversion - Check conversion of given expression to boolean.
7847/// Input argument E is a logical expression.
7848void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) {
7849  ::CheckBoolLikeConversion(*this, E, CC);
7850}
7851
7852/// Diagnose when expression is an integer constant expression and its evaluation
7853/// results in integer overflow
7854void Sema::CheckForIntOverflow (Expr *E) {
7855  if (isa<BinaryOperator>(E->IgnoreParenCasts()))
7856    E->IgnoreParenCasts()->EvaluateForOverflow(Context);
7857  else if (auto InitList = dyn_cast<InitListExpr>(E))
7858    for (Expr *E : InitList->inits())
7859      if (isa<BinaryOperator>(E->IgnoreParenCasts()))
7860        E->IgnoreParenCasts()->EvaluateForOverflow(Context);
7861}
7862
7863namespace {
7864/// \brief Visitor for expressions which looks for unsequenced operations on the
7865/// same object.
7866class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> {
7867  typedef EvaluatedExprVisitor<SequenceChecker> Base;
7868
7869  /// \brief A tree of sequenced regions within an expression. Two regions are
7870  /// unsequenced if one is an ancestor or a descendent of the other. When we
7871  /// finish processing an expression with sequencing, such as a comma
7872  /// expression, we fold its tree nodes into its parent, since they are
7873  /// unsequenced with respect to nodes we will visit later.
7874  class SequenceTree {
7875    struct Value {
7876      explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {}
7877      unsigned Parent : 31;
7878      bool Merged : 1;
7879    };
7880    SmallVector<Value, 8> Values;
7881
7882  public:
7883    /// \brief A region within an expression which may be sequenced with respect
7884    /// to some other region.
7885    class Seq {
7886      explicit Seq(unsigned N) : Index(N) {}
7887      unsigned Index;
7888      friend class SequenceTree;
7889    public:
7890      Seq() : Index(0) {}
7891    };
7892
7893    SequenceTree() { Values.push_back(Value(0)); }
7894    Seq root() const { return Seq(0); }
7895
7896    /// \brief Create a new sequence of operations, which is an unsequenced
7897    /// subset of \p Parent. This sequence of operations is sequenced with
7898    /// respect to other children of \p Parent.
7899    Seq allocate(Seq Parent) {
7900      Values.push_back(Value(Parent.Index));
7901      return Seq(Values.size() - 1);
7902    }
7903
7904    /// \brief Merge a sequence of operations into its parent.
7905    void merge(Seq S) {
7906      Values[S.Index].Merged = true;
7907    }
7908
7909    /// \brief Determine whether two operations are unsequenced. This operation
7910    /// is asymmetric: \p Cur should be the more recent sequence, and \p Old
7911    /// should have been merged into its parent as appropriate.
7912    bool isUnsequenced(Seq Cur, Seq Old) {
7913      unsigned C = representative(Cur.Index);
7914      unsigned Target = representative(Old.Index);
7915      while (C >= Target) {
7916        if (C == Target)
7917          return true;
7918        C = Values[C].Parent;
7919      }
7920      return false;
7921    }
7922
7923  private:
7924    /// \brief Pick a representative for a sequence.
7925    unsigned representative(unsigned K) {
7926      if (Values[K].Merged)
7927        // Perform path compression as we go.
7928        return Values[K].Parent = representative(Values[K].Parent);
7929      return K;
7930    }
7931  };
7932
7933  /// An object for which we can track unsequenced uses.
7934  typedef NamedDecl *Object;
7935
7936  /// Different flavors of object usage which we track. We only track the
7937  /// least-sequenced usage of each kind.
7938  enum UsageKind {
7939    /// A read of an object. Multiple unsequenced reads are OK.
7940    UK_Use,
7941    /// A modification of an object which is sequenced before the value
7942    /// computation of the expression, such as ++n in C++.
7943    UK_ModAsValue,
7944    /// A modification of an object which is not sequenced before the value
7945    /// computation of the expression, such as n++.
7946    UK_ModAsSideEffect,
7947
7948    UK_Count = UK_ModAsSideEffect + 1
7949  };
7950
7951  struct Usage {
7952    Usage() : Use(nullptr), Seq() {}
7953    Expr *Use;
7954    SequenceTree::Seq Seq;
7955  };
7956
7957  struct UsageInfo {
7958    UsageInfo() : Diagnosed(false) {}
7959    Usage Uses[UK_Count];
7960    /// Have we issued a diagnostic for this variable already?
7961    bool Diagnosed;
7962  };
7963  typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap;
7964
7965  Sema &SemaRef;
7966  /// Sequenced regions within the expression.
7967  SequenceTree Tree;
7968  /// Declaration modifications and references which we have seen.
7969  UsageInfoMap UsageMap;
7970  /// The region we are currently within.
7971  SequenceTree::Seq Region;
7972  /// Filled in with declarations which were modified as a side-effect
7973  /// (that is, post-increment operations).
7974  SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect;
7975  /// Expressions to check later. We defer checking these to reduce
7976  /// stack usage.
7977  SmallVectorImpl<Expr *> &WorkList;
7978
7979  /// RAII object wrapping the visitation of a sequenced subexpression of an
7980  /// expression. At the end of this process, the side-effects of the evaluation
7981  /// become sequenced with respect to the value computation of the result, so
7982  /// we downgrade any UK_ModAsSideEffect within the evaluation to
7983  /// UK_ModAsValue.
7984  struct SequencedSubexpression {
7985    SequencedSubexpression(SequenceChecker &Self)
7986      : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) {
7987      Self.ModAsSideEffect = &ModAsSideEffect;
7988    }
7989    ~SequencedSubexpression() {
7990      for (auto MI = ModAsSideEffect.rbegin(), ME = ModAsSideEffect.rend();
7991           MI != ME; ++MI) {
7992        UsageInfo &U = Self.UsageMap[MI->first];
7993        auto &SideEffectUsage = U.Uses[UK_ModAsSideEffect];
7994        Self.addUsage(U, MI->first, SideEffectUsage.Use, UK_ModAsValue);
7995        SideEffectUsage = MI->second;
7996      }
7997      Self.ModAsSideEffect = OldModAsSideEffect;
7998    }
7999
8000    SequenceChecker &Self;
8001    SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect;
8002    SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect;
8003  };
8004
8005  /// RAII object wrapping the visitation of a subexpression which we might
8006  /// choose to evaluate as a constant. If any subexpression is evaluated and
8007  /// found to be non-constant, this allows us to suppress the evaluation of
8008  /// the outer expression.
8009  class EvaluationTracker {
8010  public:
8011    EvaluationTracker(SequenceChecker &Self)
8012        : Self(Self), Prev(Self.EvalTracker), EvalOK(true) {
8013      Self.EvalTracker = this;
8014    }
8015    ~EvaluationTracker() {
8016      Self.EvalTracker = Prev;
8017      if (Prev)
8018        Prev->EvalOK &= EvalOK;
8019    }
8020
8021    bool evaluate(const Expr *E, bool &Result) {
8022      if (!EvalOK || E->isValueDependent())
8023        return false;
8024      EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context);
8025      return EvalOK;
8026    }
8027
8028  private:
8029    SequenceChecker &Self;
8030    EvaluationTracker *Prev;
8031    bool EvalOK;
8032  } *EvalTracker;
8033
8034  /// \brief Find the object which is produced by the specified expression,
8035  /// if any.
8036  Object getObject(Expr *E, bool Mod) const {
8037    E = E->IgnoreParenCasts();
8038    if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
8039      if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec))
8040        return getObject(UO->getSubExpr(), Mod);
8041    } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
8042      if (BO->getOpcode() == BO_Comma)
8043        return getObject(BO->getRHS(), Mod);
8044      if (Mod && BO->isAssignmentOp())
8045        return getObject(BO->getLHS(), Mod);
8046    } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
8047      // FIXME: Check for more interesting cases, like "x.n = ++x.n".
8048      if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts()))
8049        return ME->getMemberDecl();
8050    } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
8051      // FIXME: If this is a reference, map through to its value.
8052      return DRE->getDecl();
8053    return nullptr;
8054  }
8055
8056  /// \brief Note that an object was modified or used by an expression.
8057  void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) {
8058    Usage &U = UI.Uses[UK];
8059    if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) {
8060      if (UK == UK_ModAsSideEffect && ModAsSideEffect)
8061        ModAsSideEffect->push_back(std::make_pair(O, U));
8062      U.Use = Ref;
8063      U.Seq = Region;
8064    }
8065  }
8066  /// \brief Check whether a modification or use conflicts with a prior usage.
8067  void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind,
8068                  bool IsModMod) {
8069    if (UI.Diagnosed)
8070      return;
8071
8072    const Usage &U = UI.Uses[OtherKind];
8073    if (!U.Use || !Tree.isUnsequenced(Region, U.Seq))
8074      return;
8075
8076    Expr *Mod = U.Use;
8077    Expr *ModOrUse = Ref;
8078    if (OtherKind == UK_Use)
8079      std::swap(Mod, ModOrUse);
8080
8081    SemaRef.Diag(Mod->getExprLoc(),
8082                 IsModMod ? diag::warn_unsequenced_mod_mod
8083                          : diag::warn_unsequenced_mod_use)
8084      << O << SourceRange(ModOrUse->getExprLoc());
8085    UI.Diagnosed = true;
8086  }
8087
8088  void notePreUse(Object O, Expr *Use) {
8089    UsageInfo &U = UsageMap[O];
8090    // Uses conflict with other modifications.
8091    checkUsage(O, U, Use, UK_ModAsValue, false);
8092  }
8093  void notePostUse(Object O, Expr *Use) {
8094    UsageInfo &U = UsageMap[O];
8095    checkUsage(O, U, Use, UK_ModAsSideEffect, false);
8096    addUsage(U, O, Use, UK_Use);
8097  }
8098
8099  void notePreMod(Object O, Expr *Mod) {
8100    UsageInfo &U = UsageMap[O];
8101    // Modifications conflict with other modifications and with uses.
8102    checkUsage(O, U, Mod, UK_ModAsValue, true);
8103    checkUsage(O, U, Mod, UK_Use, false);
8104  }
8105  void notePostMod(Object O, Expr *Use, UsageKind UK) {
8106    UsageInfo &U = UsageMap[O];
8107    checkUsage(O, U, Use, UK_ModAsSideEffect, true);
8108    addUsage(U, O, Use, UK);
8109  }
8110
8111public:
8112  SequenceChecker(Sema &S, Expr *E, SmallVectorImpl<Expr *> &WorkList)
8113      : Base(S.Context), SemaRef(S), Region(Tree.root()),
8114        ModAsSideEffect(nullptr), WorkList(WorkList), EvalTracker(nullptr) {
8115    Visit(E);
8116  }
8117
8118  void VisitStmt(Stmt *S) {
8119    // Skip all statements which aren't expressions for now.
8120  }
8121
8122  void VisitExpr(Expr *E) {
8123    // By default, just recurse to evaluated subexpressions.
8124    Base::VisitStmt(E);
8125  }
8126
8127  void VisitCastExpr(CastExpr *E) {
8128    Object O = Object();
8129    if (E->getCastKind() == CK_LValueToRValue)
8130      O = getObject(E->getSubExpr(), false);
8131
8132    if (O)
8133      notePreUse(O, E);
8134    VisitExpr(E);
8135    if (O)
8136      notePostUse(O, E);
8137  }
8138
8139  void VisitBinComma(BinaryOperator *BO) {
8140    // C++11 [expr.comma]p1:
8141    //   Every value computation and side effect associated with the left
8142    //   expression is sequenced before every value computation and side
8143    //   effect associated with the right expression.
8144    SequenceTree::Seq LHS = Tree.allocate(Region);
8145    SequenceTree::Seq RHS = Tree.allocate(Region);
8146    SequenceTree::Seq OldRegion = Region;
8147
8148    {
8149      SequencedSubexpression SeqLHS(*this);
8150      Region = LHS;
8151      Visit(BO->getLHS());
8152    }
8153
8154    Region = RHS;
8155    Visit(BO->getRHS());
8156
8157    Region = OldRegion;
8158
8159    // Forget that LHS and RHS are sequenced. They are both unsequenced
8160    // with respect to other stuff.
8161    Tree.merge(LHS);
8162    Tree.merge(RHS);
8163  }
8164
8165  void VisitBinAssign(BinaryOperator *BO) {
8166    // The modification is sequenced after the value computation of the LHS
8167    // and RHS, so check it before inspecting the operands and update the
8168    // map afterwards.
8169    Object O = getObject(BO->getLHS(), true);
8170    if (!O)
8171      return VisitExpr(BO);
8172
8173    notePreMod(O, BO);
8174
8175    // C++11 [expr.ass]p7:
8176    //   E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated
8177    //   only once.
8178    //
8179    // Therefore, for a compound assignment operator, O is considered used
8180    // everywhere except within the evaluation of E1 itself.
8181    if (isa<CompoundAssignOperator>(BO))
8182      notePreUse(O, BO);
8183
8184    Visit(BO->getLHS());
8185
8186    if (isa<CompoundAssignOperator>(BO))
8187      notePostUse(O, BO);
8188
8189    Visit(BO->getRHS());
8190
8191    // C++11 [expr.ass]p1:
8192    //   the assignment is sequenced [...] before the value computation of the
8193    //   assignment expression.
8194    // C11 6.5.16/3 has no such rule.
8195    notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue
8196                                                       : UK_ModAsSideEffect);
8197  }
8198  void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) {
8199    VisitBinAssign(CAO);
8200  }
8201
8202  void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
8203  void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
8204  void VisitUnaryPreIncDec(UnaryOperator *UO) {
8205    Object O = getObject(UO->getSubExpr(), true);
8206    if (!O)
8207      return VisitExpr(UO);
8208
8209    notePreMod(O, UO);
8210    Visit(UO->getSubExpr());
8211    // C++11 [expr.pre.incr]p1:
8212    //   the expression ++x is equivalent to x+=1
8213    notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue
8214                                                       : UK_ModAsSideEffect);
8215  }
8216
8217  void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
8218  void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
8219  void VisitUnaryPostIncDec(UnaryOperator *UO) {
8220    Object O = getObject(UO->getSubExpr(), true);
8221    if (!O)
8222      return VisitExpr(UO);
8223
8224    notePreMod(O, UO);
8225    Visit(UO->getSubExpr());
8226    notePostMod(O, UO, UK_ModAsSideEffect);
8227  }
8228
8229  /// Don't visit the RHS of '&&' or '||' if it might not be evaluated.
8230  void VisitBinLOr(BinaryOperator *BO) {
8231    // The side-effects of the LHS of an '&&' are sequenced before the
8232    // value computation of the RHS, and hence before the value computation
8233    // of the '&&' itself, unless the LHS evaluates to zero. We treat them
8234    // as if they were unconditionally sequenced.
8235    EvaluationTracker Eval(*this);
8236    {
8237      SequencedSubexpression Sequenced(*this);
8238      Visit(BO->getLHS());
8239    }
8240
8241    bool Result;
8242    if (Eval.evaluate(BO->getLHS(), Result)) {
8243      if (!Result)
8244        Visit(BO->getRHS());
8245    } else {
8246      // Check for unsequenced operations in the RHS, treating it as an
8247      // entirely separate evaluation.
8248      //
8249      // FIXME: If there are operations in the RHS which are unsequenced
8250      // with respect to operations outside the RHS, and those operations
8251      // are unconditionally evaluated, diagnose them.
8252      WorkList.push_back(BO->getRHS());
8253    }
8254  }
8255  void VisitBinLAnd(BinaryOperator *BO) {
8256    EvaluationTracker Eval(*this);
8257    {
8258      SequencedSubexpression Sequenced(*this);
8259      Visit(BO->getLHS());
8260    }
8261
8262    bool Result;
8263    if (Eval.evaluate(BO->getLHS(), Result)) {
8264      if (Result)
8265        Visit(BO->getRHS());
8266    } else {
8267      WorkList.push_back(BO->getRHS());
8268    }
8269  }
8270
8271  // Only visit the condition, unless we can be sure which subexpression will
8272  // be chosen.
8273  void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) {
8274    EvaluationTracker Eval(*this);
8275    {
8276      SequencedSubexpression Sequenced(*this);
8277      Visit(CO->getCond());
8278    }
8279
8280    bool Result;
8281    if (Eval.evaluate(CO->getCond(), Result))
8282      Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr());
8283    else {
8284      WorkList.push_back(CO->getTrueExpr());
8285      WorkList.push_back(CO->getFalseExpr());
8286    }
8287  }
8288
8289  void VisitCallExpr(CallExpr *CE) {
8290    // C++11 [intro.execution]p15:
8291    //   When calling a function [...], every value computation and side effect
8292    //   associated with any argument expression, or with the postfix expression
8293    //   designating the called function, is sequenced before execution of every
8294    //   expression or statement in the body of the function [and thus before
8295    //   the value computation of its result].
8296    SequencedSubexpression Sequenced(*this);
8297    Base::VisitCallExpr(CE);
8298
8299    // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions.
8300  }
8301
8302  void VisitCXXConstructExpr(CXXConstructExpr *CCE) {
8303    // This is a call, so all subexpressions are sequenced before the result.
8304    SequencedSubexpression Sequenced(*this);
8305
8306    if (!CCE->isListInitialization())
8307      return VisitExpr(CCE);
8308
8309    // In C++11, list initializations are sequenced.
8310    SmallVector<SequenceTree::Seq, 32> Elts;
8311    SequenceTree::Seq Parent = Region;
8312    for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(),
8313                                        E = CCE->arg_end();
8314         I != E; ++I) {
8315      Region = Tree.allocate(Parent);
8316      Elts.push_back(Region);
8317      Visit(*I);
8318    }
8319
8320    // Forget that the initializers are sequenced.
8321    Region = Parent;
8322    for (unsigned I = 0; I < Elts.size(); ++I)
8323      Tree.merge(Elts[I]);
8324  }
8325
8326  void VisitInitListExpr(InitListExpr *ILE) {
8327    if (!SemaRef.getLangOpts().CPlusPlus11)
8328      return VisitExpr(ILE);
8329
8330    // In C++11, list initializations are sequenced.
8331    SmallVector<SequenceTree::Seq, 32> Elts;
8332    SequenceTree::Seq Parent = Region;
8333    for (unsigned I = 0; I < ILE->getNumInits(); ++I) {
8334      Expr *E = ILE->getInit(I);
8335      if (!E) continue;
8336      Region = Tree.allocate(Parent);
8337      Elts.push_back(Region);
8338      Visit(E);
8339    }
8340
8341    // Forget that the initializers are sequenced.
8342    Region = Parent;
8343    for (unsigned I = 0; I < Elts.size(); ++I)
8344      Tree.merge(Elts[I]);
8345  }
8346};
8347}
8348
8349void Sema::CheckUnsequencedOperations(Expr *E) {
8350  SmallVector<Expr *, 8> WorkList;
8351  WorkList.push_back(E);
8352  while (!WorkList.empty()) {
8353    Expr *Item = WorkList.pop_back_val();
8354    SequenceChecker(*this, Item, WorkList);
8355  }
8356}
8357
8358void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc,
8359                              bool IsConstexpr) {
8360  CheckImplicitConversions(E, CheckLoc);
8361  CheckUnsequencedOperations(E);
8362  if (!IsConstexpr && !E->isValueDependent())
8363    CheckForIntOverflow(E);
8364}
8365
8366void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
8367                                       FieldDecl *BitField,
8368                                       Expr *Init) {
8369  (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
8370}
8371
8372static void diagnoseArrayStarInParamType(Sema &S, QualType PType,
8373                                         SourceLocation Loc) {
8374  if (!PType->isVariablyModifiedType())
8375    return;
8376  if (const auto *PointerTy = dyn_cast<PointerType>(PType)) {
8377    diagnoseArrayStarInParamType(S, PointerTy->getPointeeType(), Loc);
8378    return;
8379  }
8380  if (const auto *ReferenceTy = dyn_cast<ReferenceType>(PType)) {
8381    diagnoseArrayStarInParamType(S, ReferenceTy->getPointeeType(), Loc);
8382    return;
8383  }
8384  if (const auto *ParenTy = dyn_cast<ParenType>(PType)) {
8385    diagnoseArrayStarInParamType(S, ParenTy->getInnerType(), Loc);
8386    return;
8387  }
8388
8389  const ArrayType *AT = S.Context.getAsArrayType(PType);
8390  if (!AT)
8391    return;
8392
8393  if (AT->getSizeModifier() != ArrayType::Star) {
8394    diagnoseArrayStarInParamType(S, AT->getElementType(), Loc);
8395    return;
8396  }
8397
8398  S.Diag(Loc, diag::err_array_star_in_function_definition);
8399}
8400
8401/// CheckParmsForFunctionDef - Check that the parameters of the given
8402/// function are appropriate for the definition of a function. This
8403/// takes care of any checks that cannot be performed on the
8404/// declaration itself, e.g., that the types of each of the function
8405/// parameters are complete.
8406bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P,
8407                                    ParmVarDecl *const *PEnd,
8408                                    bool CheckParameterNames) {
8409  bool HasInvalidParm = false;
8410  for (; P != PEnd; ++P) {
8411    ParmVarDecl *Param = *P;
8412
8413    // C99 6.7.5.3p4: the parameters in a parameter type list in a
8414    // function declarator that is part of a function definition of
8415    // that function shall not have incomplete type.
8416    //
8417    // This is also C++ [dcl.fct]p6.
8418    if (!Param->isInvalidDecl() &&
8419        RequireCompleteType(Param->getLocation(), Param->getType(),
8420                            diag::err_typecheck_decl_incomplete_type)) {
8421      Param->setInvalidDecl();
8422      HasInvalidParm = true;
8423    }
8424
8425    // C99 6.9.1p5: If the declarator includes a parameter type list, the
8426    // declaration of each parameter shall include an identifier.
8427    if (CheckParameterNames &&
8428        Param->getIdentifier() == nullptr &&
8429        !Param->isImplicit() &&
8430        !getLangOpts().CPlusPlus)
8431      Diag(Param->getLocation(), diag::err_parameter_name_omitted);
8432
8433    // C99 6.7.5.3p12:
8434    //   If the function declarator is not part of a definition of that
8435    //   function, parameters may have incomplete type and may use the [*]
8436    //   notation in their sequences of declarator specifiers to specify
8437    //   variable length array types.
8438    QualType PType = Param->getOriginalType();
8439    // FIXME: This diagnostic should point the '[*]' if source-location
8440    // information is added for it.
8441    diagnoseArrayStarInParamType(*this, PType, Param->getLocation());
8442
8443    // MSVC destroys objects passed by value in the callee.  Therefore a
8444    // function definition which takes such a parameter must be able to call the
8445    // object's destructor.  However, we don't perform any direct access check
8446    // on the dtor.
8447    if (getLangOpts().CPlusPlus && Context.getTargetInfo()
8448                                       .getCXXABI()
8449                                       .areArgsDestroyedLeftToRightInCallee()) {
8450      if (!Param->isInvalidDecl()) {
8451        if (const RecordType *RT = Param->getType()->getAs<RecordType>()) {
8452          CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
8453          if (!ClassDecl->isInvalidDecl() &&
8454              !ClassDecl->hasIrrelevantDestructor() &&
8455              !ClassDecl->isDependentContext()) {
8456            CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl);
8457            MarkFunctionReferenced(Param->getLocation(), Destructor);
8458            DiagnoseUseOfDecl(Destructor, Param->getLocation());
8459          }
8460        }
8461      }
8462    }
8463
8464    // Parameters with the pass_object_size attribute only need to be marked
8465    // constant at function definitions. Because we lack information about
8466    // whether we're on a declaration or definition when we're instantiating the
8467    // attribute, we need to check for constness here.
8468    if (const auto *Attr = Param->getAttr<PassObjectSizeAttr>())
8469      if (!Param->getType().isConstQualified())
8470        Diag(Param->getLocation(), diag::err_attribute_pointers_only)
8471            << Attr->getSpelling() << 1;
8472  }
8473
8474  return HasInvalidParm;
8475}
8476
8477/// CheckCastAlign - Implements -Wcast-align, which warns when a
8478/// pointer cast increases the alignment requirements.
8479void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
8480  // This is actually a lot of work to potentially be doing on every
8481  // cast; don't do it if we're ignoring -Wcast_align (as is the default).
8482  if (getDiagnostics().isIgnored(diag::warn_cast_align, TRange.getBegin()))
8483    return;
8484
8485  // Ignore dependent types.
8486  if (T->isDependentType() || Op->getType()->isDependentType())
8487    return;
8488
8489  // Require that the destination be a pointer type.
8490  const PointerType *DestPtr = T->getAs<PointerType>();
8491  if (!DestPtr) return;
8492
8493  // If the destination has alignment 1, we're done.
8494  QualType DestPointee = DestPtr->getPointeeType();
8495  if (DestPointee->isIncompleteType()) return;
8496  CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
8497  if (DestAlign.isOne()) return;
8498
8499  // Require that the source be a pointer type.
8500  const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
8501  if (!SrcPtr) return;
8502  QualType SrcPointee = SrcPtr->getPointeeType();
8503
8504  // Whitelist casts from cv void*.  We already implicitly
8505  // whitelisted casts to cv void*, since they have alignment 1.
8506  // Also whitelist casts involving incomplete types, which implicitly
8507  // includes 'void'.
8508  if (SrcPointee->isIncompleteType()) return;
8509
8510  CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
8511  if (SrcAlign >= DestAlign) return;
8512
8513  Diag(TRange.getBegin(), diag::warn_cast_align)
8514    << Op->getType() << T
8515    << static_cast<unsigned>(SrcAlign.getQuantity())
8516    << static_cast<unsigned>(DestAlign.getQuantity())
8517    << TRange << Op->getSourceRange();
8518}
8519
8520static const Type* getElementType(const Expr *BaseExpr) {
8521  const Type* EltType = BaseExpr->getType().getTypePtr();
8522  if (EltType->isAnyPointerType())
8523    return EltType->getPointeeType().getTypePtr();
8524  else if (EltType->isArrayType())
8525    return EltType->getBaseElementTypeUnsafe();
8526  return EltType;
8527}
8528
8529/// \brief Check whether this array fits the idiom of a size-one tail padded
8530/// array member of a struct.
8531///
8532/// We avoid emitting out-of-bounds access warnings for such arrays as they are
8533/// commonly used to emulate flexible arrays in C89 code.
8534static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size,
8535                                    const NamedDecl *ND) {
8536  if (Size != 1 || !ND) return false;
8537
8538  const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
8539  if (!FD) return false;
8540
8541  // Don't consider sizes resulting from macro expansions or template argument
8542  // substitution to form C89 tail-padded arrays.
8543
8544  TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
8545  while (TInfo) {
8546    TypeLoc TL = TInfo->getTypeLoc();
8547    // Look through typedefs.
8548    if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) {
8549      const TypedefNameDecl *TDL = TTL.getTypedefNameDecl();
8550      TInfo = TDL->getTypeSourceInfo();
8551      continue;
8552    }
8553    if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) {
8554      const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
8555      if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
8556        return false;
8557    }
8558    break;
8559  }
8560
8561  const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
8562  if (!RD) return false;
8563  if (RD->isUnion()) return false;
8564  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
8565    if (!CRD->isStandardLayout()) return false;
8566  }
8567
8568  // See if this is the last field decl in the record.
8569  const Decl *D = FD;
8570  while ((D = D->getNextDeclInContext()))
8571    if (isa<FieldDecl>(D))
8572      return false;
8573  return true;
8574}
8575
8576void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
8577                            const ArraySubscriptExpr *ASE,
8578                            bool AllowOnePastEnd, bool IndexNegated) {
8579  IndexExpr = IndexExpr->IgnoreParenImpCasts();
8580  if (IndexExpr->isValueDependent())
8581    return;
8582
8583  const Type *EffectiveType = getElementType(BaseExpr);
8584  BaseExpr = BaseExpr->IgnoreParenCasts();
8585  const ConstantArrayType *ArrayTy =
8586    Context.getAsConstantArrayType(BaseExpr->getType());
8587  if (!ArrayTy)
8588    return;
8589
8590  llvm::APSInt index;
8591  if (!IndexExpr->EvaluateAsInt(index, Context, Expr::SE_AllowSideEffects))
8592    return;
8593  if (IndexNegated)
8594    index = -index;
8595
8596  const NamedDecl *ND = nullptr;
8597  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
8598    ND = dyn_cast<NamedDecl>(DRE->getDecl());
8599  if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
8600    ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
8601
8602  if (index.isUnsigned() || !index.isNegative()) {
8603    llvm::APInt size = ArrayTy->getSize();
8604    if (!size.isStrictlyPositive())
8605      return;
8606
8607    const Type* BaseType = getElementType(BaseExpr);
8608    if (BaseType != EffectiveType) {
8609      // Make sure we're comparing apples to apples when comparing index to size
8610      uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
8611      uint64_t array_typesize = Context.getTypeSize(BaseType);
8612      // Handle ptrarith_typesize being zero, such as when casting to void*
8613      if (!ptrarith_typesize) ptrarith_typesize = 1;
8614      if (ptrarith_typesize != array_typesize) {
8615        // There's a cast to a different size type involved
8616        uint64_t ratio = array_typesize / ptrarith_typesize;
8617        // TODO: Be smarter about handling cases where array_typesize is not a
8618        // multiple of ptrarith_typesize
8619        if (ptrarith_typesize * ratio == array_typesize)
8620          size *= llvm::APInt(size.getBitWidth(), ratio);
8621      }
8622    }
8623
8624    if (size.getBitWidth() > index.getBitWidth())
8625      index = index.zext(size.getBitWidth());
8626    else if (size.getBitWidth() < index.getBitWidth())
8627      size = size.zext(index.getBitWidth());
8628
8629    // For array subscripting the index must be less than size, but for pointer
8630    // arithmetic also allow the index (offset) to be equal to size since
8631    // computing the next address after the end of the array is legal and
8632    // commonly done e.g. in C++ iterators and range-based for loops.
8633    if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
8634      return;
8635
8636    // Also don't warn for arrays of size 1 which are members of some
8637    // structure. These are often used to approximate flexible arrays in C89
8638    // code.
8639    if (IsTailPaddedMemberArray(*this, size, ND))
8640      return;
8641
8642    // Suppress the warning if the subscript expression (as identified by the
8643    // ']' location) and the index expression are both from macro expansions
8644    // within a system header.
8645    if (ASE) {
8646      SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
8647          ASE->getRBracketLoc());
8648      if (SourceMgr.isInSystemHeader(RBracketLoc)) {
8649        SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
8650            IndexExpr->getLocStart());
8651        if (SourceMgr.isWrittenInSameFile(RBracketLoc, IndexLoc))
8652          return;
8653      }
8654    }
8655
8656    unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
8657    if (ASE)
8658      DiagID = diag::warn_array_index_exceeds_bounds;
8659
8660    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
8661                        PDiag(DiagID) << index.toString(10, true)
8662                          << size.toString(10, true)
8663                          << (unsigned)size.getLimitedValue(~0U)
8664                          << IndexExpr->getSourceRange());
8665  } else {
8666    unsigned DiagID = diag::warn_array_index_precedes_bounds;
8667    if (!ASE) {
8668      DiagID = diag::warn_ptr_arith_precedes_bounds;
8669      if (index.isNegative()) index = -index;
8670    }
8671
8672    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
8673                        PDiag(DiagID) << index.toString(10, true)
8674                          << IndexExpr->getSourceRange());
8675  }
8676
8677  if (!ND) {
8678    // Try harder to find a NamedDecl to point at in the note.
8679    while (const ArraySubscriptExpr *ASE =
8680           dyn_cast<ArraySubscriptExpr>(BaseExpr))
8681      BaseExpr = ASE->getBase()->IgnoreParenCasts();
8682    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
8683      ND = dyn_cast<NamedDecl>(DRE->getDecl());
8684    if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
8685      ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
8686  }
8687
8688  if (ND)
8689    DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
8690                        PDiag(diag::note_array_index_out_of_bounds)
8691                          << ND->getDeclName());
8692}
8693
8694void Sema::CheckArrayAccess(const Expr *expr) {
8695  int AllowOnePastEnd = 0;
8696  while (expr) {
8697    expr = expr->IgnoreParenImpCasts();
8698    switch (expr->getStmtClass()) {
8699      case Stmt::ArraySubscriptExprClass: {
8700        const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
8701        CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
8702                         AllowOnePastEnd > 0);
8703        return;
8704      }
8705      case Stmt::OMPArraySectionExprClass: {
8706        const OMPArraySectionExpr *ASE = cast<OMPArraySectionExpr>(expr);
8707        if (ASE->getLowerBound())
8708          CheckArrayAccess(ASE->getBase(), ASE->getLowerBound(),
8709                           /*ASE=*/nullptr, AllowOnePastEnd > 0);
8710        return;
8711      }
8712      case Stmt::UnaryOperatorClass: {
8713        // Only unwrap the * and & unary operators
8714        const UnaryOperator *UO = cast<UnaryOperator>(expr);
8715        expr = UO->getSubExpr();
8716        switch (UO->getOpcode()) {
8717          case UO_AddrOf:
8718            AllowOnePastEnd++;
8719            break;
8720          case UO_Deref:
8721            AllowOnePastEnd--;
8722            break;
8723          default:
8724            return;
8725        }
8726        break;
8727      }
8728      case Stmt::ConditionalOperatorClass: {
8729        const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
8730        if (const Expr *lhs = cond->getLHS())
8731          CheckArrayAccess(lhs);
8732        if (const Expr *rhs = cond->getRHS())
8733          CheckArrayAccess(rhs);
8734        return;
8735      }
8736      default:
8737        return;
8738    }
8739  }
8740}
8741
8742//===--- CHECK: Objective-C retain cycles ----------------------------------//
8743
8744namespace {
8745  struct RetainCycleOwner {
8746    RetainCycleOwner() : Variable(nullptr), Indirect(false) {}
8747    VarDecl *Variable;
8748    SourceRange Range;
8749    SourceLocation Loc;
8750    bool Indirect;
8751
8752    void setLocsFrom(Expr *e) {
8753      Loc = e->getExprLoc();
8754      Range = e->getSourceRange();
8755    }
8756  };
8757}
8758
8759/// Consider whether capturing the given variable can possibly lead to
8760/// a retain cycle.
8761static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
8762  // In ARC, it's captured strongly iff the variable has __strong
8763  // lifetime.  In MRR, it's captured strongly if the variable is
8764  // __block and has an appropriate type.
8765  if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
8766    return false;
8767
8768  owner.Variable = var;
8769  if (ref)
8770    owner.setLocsFrom(ref);
8771  return true;
8772}
8773
8774static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
8775  while (true) {
8776    e = e->IgnoreParens();
8777    if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
8778      switch (cast->getCastKind()) {
8779      case CK_BitCast:
8780      case CK_LValueBitCast:
8781      case CK_LValueToRValue:
8782      case CK_ARCReclaimReturnedObject:
8783        e = cast->getSubExpr();
8784        continue;
8785
8786      default:
8787        return false;
8788      }
8789    }
8790
8791    if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
8792      ObjCIvarDecl *ivar = ref->getDecl();
8793      if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
8794        return false;
8795
8796      // Try to find a retain cycle in the base.
8797      if (!findRetainCycleOwner(S, ref->getBase(), owner))
8798        return false;
8799
8800      if (ref->isFreeIvar()) owner.setLocsFrom(ref);
8801      owner.Indirect = true;
8802      return true;
8803    }
8804
8805    if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
8806      VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
8807      if (!var) return false;
8808      return considerVariable(var, ref, owner);
8809    }
8810
8811    if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
8812      if (member->isArrow()) return false;
8813
8814      // Don't count this as an indirect ownership.
8815      e = member->getBase();
8816      continue;
8817    }
8818
8819    if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
8820      // Only pay attention to pseudo-objects on property references.
8821      ObjCPropertyRefExpr *pre
8822        = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
8823                                              ->IgnoreParens());
8824      if (!pre) return false;
8825      if (pre->isImplicitProperty()) return false;
8826      ObjCPropertyDecl *property = pre->getExplicitProperty();
8827      if (!property->isRetaining() &&
8828          !(property->getPropertyIvarDecl() &&
8829            property->getPropertyIvarDecl()->getType()
8830              .getObjCLifetime() == Qualifiers::OCL_Strong))
8831          return false;
8832
8833      owner.Indirect = true;
8834      if (pre->isSuperReceiver()) {
8835        owner.Variable = S.getCurMethodDecl()->getSelfDecl();
8836        if (!owner.Variable)
8837          return false;
8838        owner.Loc = pre->getLocation();
8839        owner.Range = pre->getSourceRange();
8840        return true;
8841      }
8842      e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
8843                              ->getSourceExpr());
8844      continue;
8845    }
8846
8847    // Array ivars?
8848
8849    return false;
8850  }
8851}
8852
8853namespace {
8854  struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
8855    FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
8856      : EvaluatedExprVisitor<FindCaptureVisitor>(Context),
8857        Context(Context), Variable(variable), Capturer(nullptr),
8858        VarWillBeReased(false) {}
8859    ASTContext &Context;
8860    VarDecl *Variable;
8861    Expr *Capturer;
8862    bool VarWillBeReased;
8863
8864    void VisitDeclRefExpr(DeclRefExpr *ref) {
8865      if (ref->getDecl() == Variable && !Capturer)
8866        Capturer = ref;
8867    }
8868
8869    void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
8870      if (Capturer) return;
8871      Visit(ref->getBase());
8872      if (Capturer && ref->isFreeIvar())
8873        Capturer = ref;
8874    }
8875
8876    void VisitBlockExpr(BlockExpr *block) {
8877      // Look inside nested blocks
8878      if (block->getBlockDecl()->capturesVariable(Variable))
8879        Visit(block->getBlockDecl()->getBody());
8880    }
8881
8882    void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) {
8883      if (Capturer) return;
8884      if (OVE->getSourceExpr())
8885        Visit(OVE->getSourceExpr());
8886    }
8887    void VisitBinaryOperator(BinaryOperator *BinOp) {
8888      if (!Variable || VarWillBeReased || BinOp->getOpcode() != BO_Assign)
8889        return;
8890      Expr *LHS = BinOp->getLHS();
8891      if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(LHS)) {
8892        if (DRE->getDecl() != Variable)
8893          return;
8894        if (Expr *RHS = BinOp->getRHS()) {
8895          RHS = RHS->IgnoreParenCasts();
8896          llvm::APSInt Value;
8897          VarWillBeReased =
8898            (RHS && RHS->isIntegerConstantExpr(Value, Context) && Value == 0);
8899        }
8900      }
8901    }
8902  };
8903}
8904
8905/// Check whether the given argument is a block which captures a
8906/// variable.
8907static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
8908  assert(owner.Variable && owner.Loc.isValid());
8909
8910  e = e->IgnoreParenCasts();
8911
8912  // Look through [^{...} copy] and Block_copy(^{...}).
8913  if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) {
8914    Selector Cmd = ME->getSelector();
8915    if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") {
8916      e = ME->getInstanceReceiver();
8917      if (!e)
8918        return nullptr;
8919      e = e->IgnoreParenCasts();
8920    }
8921  } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) {
8922    if (CE->getNumArgs() == 1) {
8923      FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl());
8924      if (Fn) {
8925        const IdentifierInfo *FnI = Fn->getIdentifier();
8926        if (FnI && FnI->isStr("_Block_copy")) {
8927          e = CE->getArg(0)->IgnoreParenCasts();
8928        }
8929      }
8930    }
8931  }
8932
8933  BlockExpr *block = dyn_cast<BlockExpr>(e);
8934  if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
8935    return nullptr;
8936
8937  FindCaptureVisitor visitor(S.Context, owner.Variable);
8938  visitor.Visit(block->getBlockDecl()->getBody());
8939  return visitor.VarWillBeReased ? nullptr : visitor.Capturer;
8940}
8941
8942static void diagnoseRetainCycle(Sema &S, Expr *capturer,
8943                                RetainCycleOwner &owner) {
8944  assert(capturer);
8945  assert(owner.Variable && owner.Loc.isValid());
8946
8947  S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
8948    << owner.Variable << capturer->getSourceRange();
8949  S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
8950    << owner.Indirect << owner.Range;
8951}
8952
8953/// Check for a keyword selector that starts with the word 'add' or
8954/// 'set'.
8955static bool isSetterLikeSelector(Selector sel) {
8956  if (sel.isUnarySelector()) return false;
8957
8958  StringRef str = sel.getNameForSlot(0);
8959  while (!str.empty() && str.front() == '_') str = str.substr(1);
8960  if (str.startswith("set"))
8961    str = str.substr(3);
8962  else if (str.startswith("add")) {
8963    // Specially whitelist 'addOperationWithBlock:'.
8964    if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
8965      return false;
8966    str = str.substr(3);
8967  }
8968  else
8969    return false;
8970
8971  if (str.empty()) return true;
8972  return !isLowercase(str.front());
8973}
8974
8975static Optional<int> GetNSMutableArrayArgumentIndex(Sema &S,
8976                                                    ObjCMessageExpr *Message) {
8977  bool IsMutableArray = S.NSAPIObj->isSubclassOfNSClass(
8978                                                Message->getReceiverInterface(),
8979                                                NSAPI::ClassId_NSMutableArray);
8980  if (!IsMutableArray) {
8981    return None;
8982  }
8983
8984  Selector Sel = Message->getSelector();
8985
8986  Optional<NSAPI::NSArrayMethodKind> MKOpt =
8987    S.NSAPIObj->getNSArrayMethodKind(Sel);
8988  if (!MKOpt) {
8989    return None;
8990  }
8991
8992  NSAPI::NSArrayMethodKind MK = *MKOpt;
8993
8994  switch (MK) {
8995    case NSAPI::NSMutableArr_addObject:
8996    case NSAPI::NSMutableArr_insertObjectAtIndex:
8997    case NSAPI::NSMutableArr_setObjectAtIndexedSubscript:
8998      return 0;
8999    case NSAPI::NSMutableArr_replaceObjectAtIndex:
9000      return 1;
9001
9002    default:
9003      return None;
9004  }
9005
9006  return None;
9007}
9008
9009static
9010Optional<int> GetNSMutableDictionaryArgumentIndex(Sema &S,
9011                                                  ObjCMessageExpr *Message) {
9012  bool IsMutableDictionary = S.NSAPIObj->isSubclassOfNSClass(
9013                                            Message->getReceiverInterface(),
9014                                            NSAPI::ClassId_NSMutableDictionary);
9015  if (!IsMutableDictionary) {
9016    return None;
9017  }
9018
9019  Selector Sel = Message->getSelector();
9020
9021  Optional<NSAPI::NSDictionaryMethodKind> MKOpt =
9022    S.NSAPIObj->getNSDictionaryMethodKind(Sel);
9023  if (!MKOpt) {
9024    return None;
9025  }
9026
9027  NSAPI::NSDictionaryMethodKind MK = *MKOpt;
9028
9029  switch (MK) {
9030    case NSAPI::NSMutableDict_setObjectForKey:
9031    case NSAPI::NSMutableDict_setValueForKey:
9032    case NSAPI::NSMutableDict_setObjectForKeyedSubscript:
9033      return 0;
9034
9035    default:
9036      return None;
9037  }
9038
9039  return None;
9040}
9041
9042static Optional<int> GetNSSetArgumentIndex(Sema &S, ObjCMessageExpr *Message) {
9043  bool IsMutableSet = S.NSAPIObj->isSubclassOfNSClass(
9044                                                Message->getReceiverInterface(),
9045                                                NSAPI::ClassId_NSMutableSet);
9046
9047  bool IsMutableOrderedSet = S.NSAPIObj->isSubclassOfNSClass(
9048                                            Message->getReceiverInterface(),
9049                                            NSAPI::ClassId_NSMutableOrderedSet);
9050  if (!IsMutableSet && !IsMutableOrderedSet) {
9051    return None;
9052  }
9053
9054  Selector Sel = Message->getSelector();
9055
9056  Optional<NSAPI::NSSetMethodKind> MKOpt = S.NSAPIObj->getNSSetMethodKind(Sel);
9057  if (!MKOpt) {
9058    return None;
9059  }
9060
9061  NSAPI::NSSetMethodKind MK = *MKOpt;
9062
9063  switch (MK) {
9064    case NSAPI::NSMutableSet_addObject:
9065    case NSAPI::NSOrderedSet_setObjectAtIndex:
9066    case NSAPI::NSOrderedSet_setObjectAtIndexedSubscript:
9067    case NSAPI::NSOrderedSet_insertObjectAtIndex:
9068      return 0;
9069    case NSAPI::NSOrderedSet_replaceObjectAtIndexWithObject:
9070      return 1;
9071  }
9072
9073  return None;
9074}
9075
9076void Sema::CheckObjCCircularContainer(ObjCMessageExpr *Message) {
9077  if (!Message->isInstanceMessage()) {
9078    return;
9079  }
9080
9081  Optional<int> ArgOpt;
9082
9083  if (!(ArgOpt = GetNSMutableArrayArgumentIndex(*this, Message)) &&
9084      !(ArgOpt = GetNSMutableDictionaryArgumentIndex(*this, Message)) &&
9085      !(ArgOpt = GetNSSetArgumentIndex(*this, Message))) {
9086    return;
9087  }
9088
9089  int ArgIndex = *ArgOpt;
9090
9091  Expr *Arg = Message->getArg(ArgIndex)->IgnoreImpCasts();
9092  if (OpaqueValueExpr *OE = dyn_cast<OpaqueValueExpr>(Arg)) {
9093    Arg = OE->getSourceExpr()->IgnoreImpCasts();
9094  }
9095
9096  if (Message->getReceiverKind() == ObjCMessageExpr::SuperInstance) {
9097    if (DeclRefExpr *ArgRE = dyn_cast<DeclRefExpr>(Arg)) {
9098      if (ArgRE->isObjCSelfExpr()) {
9099        Diag(Message->getSourceRange().getBegin(),
9100             diag::warn_objc_circular_container)
9101          << ArgRE->getDecl()->getName() << StringRef("super");
9102      }
9103    }
9104  } else {
9105    Expr *Receiver = Message->getInstanceReceiver()->IgnoreImpCasts();
9106
9107    if (OpaqueValueExpr *OE = dyn_cast<OpaqueValueExpr>(Receiver)) {
9108      Receiver = OE->getSourceExpr()->IgnoreImpCasts();
9109    }
9110
9111    if (DeclRefExpr *ReceiverRE = dyn_cast<DeclRefExpr>(Receiver)) {
9112      if (DeclRefExpr *ArgRE = dyn_cast<DeclRefExpr>(Arg)) {
9113        if (ReceiverRE->getDecl() == ArgRE->getDecl()) {
9114          ValueDecl *Decl = ReceiverRE->getDecl();
9115          Diag(Message->getSourceRange().getBegin(),
9116               diag::warn_objc_circular_container)
9117            << Decl->getName() << Decl->getName();
9118          if (!ArgRE->isObjCSelfExpr()) {
9119            Diag(Decl->getLocation(),
9120                 diag::note_objc_circular_container_declared_here)
9121              << Decl->getName();
9122          }
9123        }
9124      }
9125    } else if (ObjCIvarRefExpr *IvarRE = dyn_cast<ObjCIvarRefExpr>(Receiver)) {
9126      if (ObjCIvarRefExpr *IvarArgRE = dyn_cast<ObjCIvarRefExpr>(Arg)) {
9127        if (IvarRE->getDecl() == IvarArgRE->getDecl()) {
9128          ObjCIvarDecl *Decl = IvarRE->getDecl();
9129          Diag(Message->getSourceRange().getBegin(),
9130               diag::warn_objc_circular_container)
9131            << Decl->getName() << Decl->getName();
9132          Diag(Decl->getLocation(),
9133               diag::note_objc_circular_container_declared_here)
9134            << Decl->getName();
9135        }
9136      }
9137    }
9138  }
9139
9140}
9141
9142/// Check a message send to see if it's likely to cause a retain cycle.
9143void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
9144  // Only check instance methods whose selector looks like a setter.
9145  if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
9146    return;
9147
9148  // Try to find a variable that the receiver is strongly owned by.
9149  RetainCycleOwner owner;
9150  if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
9151    if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
9152      return;
9153  } else {
9154    assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
9155    owner.Variable = getCurMethodDecl()->getSelfDecl();
9156    owner.Loc = msg->getSuperLoc();
9157    owner.Range = msg->getSuperLoc();
9158  }
9159
9160  // Check whether the receiver is captured by any of the arguments.
9161  for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
9162    if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
9163      return diagnoseRetainCycle(*this, capturer, owner);
9164}
9165
9166/// Check a property assign to see if it's likely to cause a retain cycle.
9167void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
9168  RetainCycleOwner owner;
9169  if (!findRetainCycleOwner(*this, receiver, owner))
9170    return;
9171
9172  if (Expr *capturer = findCapturingExpr(*this, argument, owner))
9173    diagnoseRetainCycle(*this, capturer, owner);
9174}
9175
9176void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) {
9177  RetainCycleOwner Owner;
9178  if (!considerVariable(Var, /*DeclRefExpr=*/nullptr, Owner))
9179    return;
9180
9181  // Because we don't have an expression for the variable, we have to set the
9182  // location explicitly here.
9183  Owner.Loc = Var->getLocation();
9184  Owner.Range = Var->getSourceRange();
9185
9186  if (Expr *Capturer = findCapturingExpr(*this, Init, Owner))
9187    diagnoseRetainCycle(*this, Capturer, Owner);
9188}
9189
9190static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc,
9191                                     Expr *RHS, bool isProperty) {
9192  // Check if RHS is an Objective-C object literal, which also can get
9193  // immediately zapped in a weak reference.  Note that we explicitly
9194  // allow ObjCStringLiterals, since those are designed to never really die.
9195  RHS = RHS->IgnoreParenImpCasts();
9196
9197  // This enum needs to match with the 'select' in
9198  // warn_objc_arc_literal_assign (off-by-1).
9199  Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS);
9200  if (Kind == Sema::LK_String || Kind == Sema::LK_None)
9201    return false;
9202
9203  S.Diag(Loc, diag::warn_arc_literal_assign)
9204    << (unsigned) Kind
9205    << (isProperty ? 0 : 1)
9206    << RHS->getSourceRange();
9207
9208  return true;
9209}
9210
9211static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc,
9212                                    Qualifiers::ObjCLifetime LT,
9213                                    Expr *RHS, bool isProperty) {
9214  // Strip off any implicit cast added to get to the one ARC-specific.
9215  while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
9216    if (cast->getCastKind() == CK_ARCConsumeObject) {
9217      S.Diag(Loc, diag::warn_arc_retained_assign)
9218        << (LT == Qualifiers::OCL_ExplicitNone)
9219        << (isProperty ? 0 : 1)
9220        << RHS->getSourceRange();
9221      return true;
9222    }
9223    RHS = cast->getSubExpr();
9224  }
9225
9226  if (LT == Qualifiers::OCL_Weak &&
9227      checkUnsafeAssignLiteral(S, Loc, RHS, isProperty))
9228    return true;
9229
9230  return false;
9231}
9232
9233bool Sema::checkUnsafeAssigns(SourceLocation Loc,
9234                              QualType LHS, Expr *RHS) {
9235  Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
9236
9237  if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
9238    return false;
9239
9240  if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false))
9241    return true;
9242
9243  return false;
9244}
9245
9246void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
9247                              Expr *LHS, Expr *RHS) {
9248  QualType LHSType;
9249  // PropertyRef on LHS type need be directly obtained from
9250  // its declaration as it has a PseudoType.
9251  ObjCPropertyRefExpr *PRE
9252    = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
9253  if (PRE && !PRE->isImplicitProperty()) {
9254    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
9255    if (PD)
9256      LHSType = PD->getType();
9257  }
9258
9259  if (LHSType.isNull())
9260    LHSType = LHS->getType();
9261
9262  Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
9263
9264  if (LT == Qualifiers::OCL_Weak) {
9265    if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc))
9266      getCurFunction()->markSafeWeakUse(LHS);
9267  }
9268
9269  if (checkUnsafeAssigns(Loc, LHSType, RHS))
9270    return;
9271
9272  // FIXME. Check for other life times.
9273  if (LT != Qualifiers::OCL_None)
9274    return;
9275
9276  if (PRE) {
9277    if (PRE->isImplicitProperty())
9278      return;
9279    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
9280    if (!PD)
9281      return;
9282
9283    unsigned Attributes = PD->getPropertyAttributes();
9284    if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
9285      // when 'assign' attribute was not explicitly specified
9286      // by user, ignore it and rely on property type itself
9287      // for lifetime info.
9288      unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
9289      if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
9290          LHSType->isObjCRetainableType())
9291        return;
9292
9293      while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
9294        if (cast->getCastKind() == CK_ARCConsumeObject) {
9295          Diag(Loc, diag::warn_arc_retained_property_assign)
9296          << RHS->getSourceRange();
9297          return;
9298        }
9299        RHS = cast->getSubExpr();
9300      }
9301    }
9302    else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) {
9303      if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true))
9304        return;
9305    }
9306  }
9307}
9308
9309//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
9310
9311namespace {
9312bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
9313                                 SourceLocation StmtLoc,
9314                                 const NullStmt *Body) {
9315  // Do not warn if the body is a macro that expands to nothing, e.g:
9316  //
9317  // #define CALL(x)
9318  // if (condition)
9319  //   CALL(0);
9320  //
9321  if (Body->hasLeadingEmptyMacro())
9322    return false;
9323
9324  // Get line numbers of statement and body.
9325  bool StmtLineInvalid;
9326  unsigned StmtLine = SourceMgr.getPresumedLineNumber(StmtLoc,
9327                                                      &StmtLineInvalid);
9328  if (StmtLineInvalid)
9329    return false;
9330
9331  bool BodyLineInvalid;
9332  unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
9333                                                      &BodyLineInvalid);
9334  if (BodyLineInvalid)
9335    return false;
9336
9337  // Warn if null statement and body are on the same line.
9338  if (StmtLine != BodyLine)
9339    return false;
9340
9341  return true;
9342}
9343} // Unnamed namespace
9344
9345void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
9346                                 const Stmt *Body,
9347                                 unsigned DiagID) {
9348  // Since this is a syntactic check, don't emit diagnostic for template
9349  // instantiations, this just adds noise.
9350  if (CurrentInstantiationScope)
9351    return;
9352
9353  // The body should be a null statement.
9354  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
9355  if (!NBody)
9356    return;
9357
9358  // Do the usual checks.
9359  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
9360    return;
9361
9362  Diag(NBody->getSemiLoc(), DiagID);
9363  Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
9364}
9365
9366void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
9367                                 const Stmt *PossibleBody) {
9368  assert(!CurrentInstantiationScope); // Ensured by caller
9369
9370  SourceLocation StmtLoc;
9371  const Stmt *Body;
9372  unsigned DiagID;
9373  if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
9374    StmtLoc = FS->getRParenLoc();
9375    Body = FS->getBody();
9376    DiagID = diag::warn_empty_for_body;
9377  } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
9378    StmtLoc = WS->getCond()->getSourceRange().getEnd();
9379    Body = WS->getBody();
9380    DiagID = diag::warn_empty_while_body;
9381  } else
9382    return; // Neither `for' nor `while'.
9383
9384  // The body should be a null statement.
9385  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
9386  if (!NBody)
9387    return;
9388
9389  // Skip expensive checks if diagnostic is disabled.
9390  if (Diags.isIgnored(DiagID, NBody->getSemiLoc()))
9391    return;
9392
9393  // Do the usual checks.
9394  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
9395    return;
9396
9397  // `for(...);' and `while(...);' are popular idioms, so in order to keep
9398  // noise level low, emit diagnostics only if for/while is followed by a
9399  // CompoundStmt, e.g.:
9400  //    for (int i = 0; i < n; i++);
9401  //    {
9402  //      a(i);
9403  //    }
9404  // or if for/while is followed by a statement with more indentation
9405  // than for/while itself:
9406  //    for (int i = 0; i < n; i++);
9407  //      a(i);
9408  bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
9409  if (!ProbableTypo) {
9410    bool BodyColInvalid;
9411    unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
9412                             PossibleBody->getLocStart(),
9413                             &BodyColInvalid);
9414    if (BodyColInvalid)
9415      return;
9416
9417    bool StmtColInvalid;
9418    unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
9419                             S->getLocStart(),
9420                             &StmtColInvalid);
9421    if (StmtColInvalid)
9422      return;
9423
9424    if (BodyCol > StmtCol)
9425      ProbableTypo = true;
9426  }
9427
9428  if (ProbableTypo) {
9429    Diag(NBody->getSemiLoc(), DiagID);
9430    Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
9431  }
9432}
9433
9434//===--- CHECK: Warn on self move with std::move. -------------------------===//
9435
9436/// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
9437void Sema::DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr,
9438                             SourceLocation OpLoc) {
9439
9440  if (Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, OpLoc))
9441    return;
9442
9443  if (!ActiveTemplateInstantiations.empty())
9444    return;
9445
9446  // Strip parens and casts away.
9447  LHSExpr = LHSExpr->IgnoreParenImpCasts();
9448  RHSExpr = RHSExpr->IgnoreParenImpCasts();
9449
9450  // Check for a call expression
9451  const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr);
9452  if (!CE || CE->getNumArgs() != 1)
9453    return;
9454
9455  // Check for a call to std::move
9456  const FunctionDecl *FD = CE->getDirectCallee();
9457  if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() ||
9458      !FD->getIdentifier()->isStr("move"))
9459    return;
9460
9461  // Get argument from std::move
9462  RHSExpr = CE->getArg(0);
9463
9464  const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr);
9465  const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr);
9466
9467  // Two DeclRefExpr's, check that the decls are the same.
9468  if (LHSDeclRef && RHSDeclRef) {
9469    if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
9470      return;
9471    if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
9472        RHSDeclRef->getDecl()->getCanonicalDecl())
9473      return;
9474
9475    Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
9476                                        << LHSExpr->getSourceRange()
9477                                        << RHSExpr->getSourceRange();
9478    return;
9479  }
9480
9481  // Member variables require a different approach to check for self moves.
9482  // MemberExpr's are the same if every nested MemberExpr refers to the same
9483  // Decl and that the base Expr's are DeclRefExpr's with the same Decl or
9484  // the base Expr's are CXXThisExpr's.
9485  const Expr *LHSBase = LHSExpr;
9486  const Expr *RHSBase = RHSExpr;
9487  const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr);
9488  const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr);
9489  if (!LHSME || !RHSME)
9490    return;
9491
9492  while (LHSME && RHSME) {
9493    if (LHSME->getMemberDecl()->getCanonicalDecl() !=
9494        RHSME->getMemberDecl()->getCanonicalDecl())
9495      return;
9496
9497    LHSBase = LHSME->getBase();
9498    RHSBase = RHSME->getBase();
9499    LHSME = dyn_cast<MemberExpr>(LHSBase);
9500    RHSME = dyn_cast<MemberExpr>(RHSBase);
9501  }
9502
9503  LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase);
9504  RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase);
9505  if (LHSDeclRef && RHSDeclRef) {
9506    if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
9507      return;
9508    if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
9509        RHSDeclRef->getDecl()->getCanonicalDecl())
9510      return;
9511
9512    Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
9513                                        << LHSExpr->getSourceRange()
9514                                        << RHSExpr->getSourceRange();
9515    return;
9516  }
9517
9518  if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase))
9519    Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
9520                                        << LHSExpr->getSourceRange()
9521                                        << RHSExpr->getSourceRange();
9522}
9523
9524//===--- Layout compatibility ----------------------------------------------//
9525
9526namespace {
9527
9528bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2);
9529
9530/// \brief Check if two enumeration types are layout-compatible.
9531bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) {
9532  // C++11 [dcl.enum] p8:
9533  // Two enumeration types are layout-compatible if they have the same
9534  // underlying type.
9535  return ED1->isComplete() && ED2->isComplete() &&
9536         C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType());
9537}
9538
9539/// \brief Check if two fields are layout-compatible.
9540bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) {
9541  if (!isLayoutCompatible(C, Field1->getType(), Field2->getType()))
9542    return false;
9543
9544  if (Field1->isBitField() != Field2->isBitField())
9545    return false;
9546
9547  if (Field1->isBitField()) {
9548    // Make sure that the bit-fields are the same length.
9549    unsigned Bits1 = Field1->getBitWidthValue(C);
9550    unsigned Bits2 = Field2->getBitWidthValue(C);
9551
9552    if (Bits1 != Bits2)
9553      return false;
9554  }
9555
9556  return true;
9557}
9558
9559/// \brief Check if two standard-layout structs are layout-compatible.
9560/// (C++11 [class.mem] p17)
9561bool isLayoutCompatibleStruct(ASTContext &C,
9562                              RecordDecl *RD1,
9563                              RecordDecl *RD2) {
9564  // If both records are C++ classes, check that base classes match.
9565  if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) {
9566    // If one of records is a CXXRecordDecl we are in C++ mode,
9567    // thus the other one is a CXXRecordDecl, too.
9568    const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2);
9569    // Check number of base classes.
9570    if (D1CXX->getNumBases() != D2CXX->getNumBases())
9571      return false;
9572
9573    // Check the base classes.
9574    for (CXXRecordDecl::base_class_const_iterator
9575               Base1 = D1CXX->bases_begin(),
9576           BaseEnd1 = D1CXX->bases_end(),
9577              Base2 = D2CXX->bases_begin();
9578         Base1 != BaseEnd1;
9579         ++Base1, ++Base2) {
9580      if (!isLayoutCompatible(C, Base1->getType(), Base2->getType()))
9581        return false;
9582    }
9583  } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) {
9584    // If only RD2 is a C++ class, it should have zero base classes.
9585    if (D2CXX->getNumBases() > 0)
9586      return false;
9587  }
9588
9589  // Check the fields.
9590  RecordDecl::field_iterator Field2 = RD2->field_begin(),
9591                             Field2End = RD2->field_end(),
9592                             Field1 = RD1->field_begin(),
9593                             Field1End = RD1->field_end();
9594  for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) {
9595    if (!isLayoutCompatible(C, *Field1, *Field2))
9596      return false;
9597  }
9598  if (Field1 != Field1End || Field2 != Field2End)
9599    return false;
9600
9601  return true;
9602}
9603
9604/// \brief Check if two standard-layout unions are layout-compatible.
9605/// (C++11 [class.mem] p18)
9606bool isLayoutCompatibleUnion(ASTContext &C,
9607                             RecordDecl *RD1,
9608                             RecordDecl *RD2) {
9609  llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields;
9610  for (auto *Field2 : RD2->fields())
9611    UnmatchedFields.insert(Field2);
9612
9613  for (auto *Field1 : RD1->fields()) {
9614    llvm::SmallPtrSet<FieldDecl *, 8>::iterator
9615        I = UnmatchedFields.begin(),
9616        E = UnmatchedFields.end();
9617
9618    for ( ; I != E; ++I) {
9619      if (isLayoutCompatible(C, Field1, *I)) {
9620        bool Result = UnmatchedFields.erase(*I);
9621        (void) Result;
9622        assert(Result);
9623        break;
9624      }
9625    }
9626    if (I == E)
9627      return false;
9628  }
9629
9630  return UnmatchedFields.empty();
9631}
9632
9633bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) {
9634  if (RD1->isUnion() != RD2->isUnion())
9635    return false;
9636
9637  if (RD1->isUnion())
9638    return isLayoutCompatibleUnion(C, RD1, RD2);
9639  else
9640    return isLayoutCompatibleStruct(C, RD1, RD2);
9641}
9642
9643/// \brief Check if two types are layout-compatible in C++11 sense.
9644bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) {
9645  if (T1.isNull() || T2.isNull())
9646    return false;
9647
9648  // C++11 [basic.types] p11:
9649  // If two types T1 and T2 are the same type, then T1 and T2 are
9650  // layout-compatible types.
9651  if (C.hasSameType(T1, T2))
9652    return true;
9653
9654  T1 = T1.getCanonicalType().getUnqualifiedType();
9655  T2 = T2.getCanonicalType().getUnqualifiedType();
9656
9657  const Type::TypeClass TC1 = T1->getTypeClass();
9658  const Type::TypeClass TC2 = T2->getTypeClass();
9659
9660  if (TC1 != TC2)
9661    return false;
9662
9663  if (TC1 == Type::Enum) {
9664    return isLayoutCompatible(C,
9665                              cast<EnumType>(T1)->getDecl(),
9666                              cast<EnumType>(T2)->getDecl());
9667  } else if (TC1 == Type::Record) {
9668    if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType())
9669      return false;
9670
9671    return isLayoutCompatible(C,
9672                              cast<RecordType>(T1)->getDecl(),
9673                              cast<RecordType>(T2)->getDecl());
9674  }
9675
9676  return false;
9677}
9678}
9679
9680//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----//
9681
9682namespace {
9683/// \brief Given a type tag expression find the type tag itself.
9684///
9685/// \param TypeExpr Type tag expression, as it appears in user's code.
9686///
9687/// \param VD Declaration of an identifier that appears in a type tag.
9688///
9689/// \param MagicValue Type tag magic value.
9690bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx,
9691                     const ValueDecl **VD, uint64_t *MagicValue) {
9692  while(true) {
9693    if (!TypeExpr)
9694      return false;
9695
9696    TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts();
9697
9698    switch (TypeExpr->getStmtClass()) {
9699    case Stmt::UnaryOperatorClass: {
9700      const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr);
9701      if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) {
9702        TypeExpr = UO->getSubExpr();
9703        continue;
9704      }
9705      return false;
9706    }
9707
9708    case Stmt::DeclRefExprClass: {
9709      const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr);
9710      *VD = DRE->getDecl();
9711      return true;
9712    }
9713
9714    case Stmt::IntegerLiteralClass: {
9715      const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr);
9716      llvm::APInt MagicValueAPInt = IL->getValue();
9717      if (MagicValueAPInt.getActiveBits() <= 64) {
9718        *MagicValue = MagicValueAPInt.getZExtValue();
9719        return true;
9720      } else
9721        return false;
9722    }
9723
9724    case Stmt::BinaryConditionalOperatorClass:
9725    case Stmt::ConditionalOperatorClass: {
9726      const AbstractConditionalOperator *ACO =
9727          cast<AbstractConditionalOperator>(TypeExpr);
9728      bool Result;
9729      if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) {
9730        if (Result)
9731          TypeExpr = ACO->getTrueExpr();
9732        else
9733          TypeExpr = ACO->getFalseExpr();
9734        continue;
9735      }
9736      return false;
9737    }
9738
9739    case Stmt::BinaryOperatorClass: {
9740      const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr);
9741      if (BO->getOpcode() == BO_Comma) {
9742        TypeExpr = BO->getRHS();
9743        continue;
9744      }
9745      return false;
9746    }
9747
9748    default:
9749      return false;
9750    }
9751  }
9752}
9753
9754/// \brief Retrieve the C type corresponding to type tag TypeExpr.
9755///
9756/// \param TypeExpr Expression that specifies a type tag.
9757///
9758/// \param MagicValues Registered magic values.
9759///
9760/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong
9761///        kind.
9762///
9763/// \param TypeInfo Information about the corresponding C type.
9764///
9765/// \returns true if the corresponding C type was found.
9766bool GetMatchingCType(
9767        const IdentifierInfo *ArgumentKind,
9768        const Expr *TypeExpr, const ASTContext &Ctx,
9769        const llvm::DenseMap<Sema::TypeTagMagicValue,
9770                             Sema::TypeTagData> *MagicValues,
9771        bool &FoundWrongKind,
9772        Sema::TypeTagData &TypeInfo) {
9773  FoundWrongKind = false;
9774
9775  // Variable declaration that has type_tag_for_datatype attribute.
9776  const ValueDecl *VD = nullptr;
9777
9778  uint64_t MagicValue;
9779
9780  if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue))
9781    return false;
9782
9783  if (VD) {
9784    if (TypeTagForDatatypeAttr *I = VD->getAttr<TypeTagForDatatypeAttr>()) {
9785      if (I->getArgumentKind() != ArgumentKind) {
9786        FoundWrongKind = true;
9787        return false;
9788      }
9789      TypeInfo.Type = I->getMatchingCType();
9790      TypeInfo.LayoutCompatible = I->getLayoutCompatible();
9791      TypeInfo.MustBeNull = I->getMustBeNull();
9792      return true;
9793    }
9794    return false;
9795  }
9796
9797  if (!MagicValues)
9798    return false;
9799
9800  llvm::DenseMap<Sema::TypeTagMagicValue,
9801                 Sema::TypeTagData>::const_iterator I =
9802      MagicValues->find(std::make_pair(ArgumentKind, MagicValue));
9803  if (I == MagicValues->end())
9804    return false;
9805
9806  TypeInfo = I->second;
9807  return true;
9808}
9809} // unnamed namespace
9810
9811void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
9812                                      uint64_t MagicValue, QualType Type,
9813                                      bool LayoutCompatible,
9814                                      bool MustBeNull) {
9815  if (!TypeTagForDatatypeMagicValues)
9816    TypeTagForDatatypeMagicValues.reset(
9817        new llvm::DenseMap<TypeTagMagicValue, TypeTagData>);
9818
9819  TypeTagMagicValue Magic(ArgumentKind, MagicValue);
9820  (*TypeTagForDatatypeMagicValues)[Magic] =
9821      TypeTagData(Type, LayoutCompatible, MustBeNull);
9822}
9823
9824namespace {
9825bool IsSameCharType(QualType T1, QualType T2) {
9826  const BuiltinType *BT1 = T1->getAs<BuiltinType>();
9827  if (!BT1)
9828    return false;
9829
9830  const BuiltinType *BT2 = T2->getAs<BuiltinType>();
9831  if (!BT2)
9832    return false;
9833
9834  BuiltinType::Kind T1Kind = BT1->getKind();
9835  BuiltinType::Kind T2Kind = BT2->getKind();
9836
9837  return (T1Kind == BuiltinType::SChar  && T2Kind == BuiltinType::Char_S) ||
9838         (T1Kind == BuiltinType::UChar  && T2Kind == BuiltinType::Char_U) ||
9839         (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) ||
9840         (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar);
9841}
9842} // unnamed namespace
9843
9844void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
9845                                    const Expr * const *ExprArgs) {
9846  const IdentifierInfo *ArgumentKind = Attr->getArgumentKind();
9847  bool IsPointerAttr = Attr->getIsPointer();
9848
9849  const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
9850  bool FoundWrongKind;
9851  TypeTagData TypeInfo;
9852  if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
9853                        TypeTagForDatatypeMagicValues.get(),
9854                        FoundWrongKind, TypeInfo)) {
9855    if (FoundWrongKind)
9856      Diag(TypeTagExpr->getExprLoc(),
9857           diag::warn_type_tag_for_datatype_wrong_kind)
9858        << TypeTagExpr->getSourceRange();
9859    return;
9860  }
9861
9862  const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
9863  if (IsPointerAttr) {
9864    // Skip implicit cast of pointer to `void *' (as a function argument).
9865    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))
9866      if (ICE->getType()->isVoidPointerType() &&
9867          ICE->getCastKind() == CK_BitCast)
9868        ArgumentExpr = ICE->getSubExpr();
9869  }
9870  QualType ArgumentType = ArgumentExpr->getType();
9871
9872  // Passing a `void*' pointer shouldn't trigger a warning.
9873  if (IsPointerAttr && ArgumentType->isVoidPointerType())
9874    return;
9875
9876  if (TypeInfo.MustBeNull) {
9877    // Type tag with matching void type requires a null pointer.
9878    if (!ArgumentExpr->isNullPointerConstant(Context,
9879                                             Expr::NPC_ValueDependentIsNotNull)) {
9880      Diag(ArgumentExpr->getExprLoc(),
9881           diag::warn_type_safety_null_pointer_required)
9882          << ArgumentKind->getName()
9883          << ArgumentExpr->getSourceRange()
9884          << TypeTagExpr->getSourceRange();
9885    }
9886    return;
9887  }
9888
9889  QualType RequiredType = TypeInfo.Type;
9890  if (IsPointerAttr)
9891    RequiredType = Context.getPointerType(RequiredType);
9892
9893  bool mismatch = false;
9894  if (!TypeInfo.LayoutCompatible) {
9895    mismatch = !Context.hasSameType(ArgumentType, RequiredType);
9896
9897    // C++11 [basic.fundamental] p1:
9898    // Plain char, signed char, and unsigned char are three distinct types.
9899    //
9900    // But we treat plain `char' as equivalent to `signed char' or `unsigned
9901    // char' depending on the current char signedness mode.
9902    if (mismatch)
9903      if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(),
9904                                           RequiredType->getPointeeType())) ||
9905          (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType)))
9906        mismatch = false;
9907  } else
9908    if (IsPointerAttr)
9909      mismatch = !isLayoutCompatible(Context,
9910                                     ArgumentType->getPointeeType(),
9911                                     RequiredType->getPointeeType());
9912    else
9913      mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
9914
9915  if (mismatch)
9916    Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
9917        << ArgumentType << ArgumentKind
9918        << TypeInfo.LayoutCompatible << RequiredType
9919        << ArgumentExpr->getSourceRange()
9920        << TypeTagExpr->getSourceRange();
9921}
9922