SemaStmt.cpp revision 288943 
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
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 semantic analysis for statements.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Sema/SemaInternal.h"
15#include "clang/AST/ASTContext.h"
16#include "clang/AST/ASTDiagnostic.h"
17#include "clang/AST/CharUnits.h"
18#include "clang/AST/CXXInheritance.h"
19#include "clang/AST/DeclObjC.h"
20#include "clang/AST/EvaluatedExprVisitor.h"
21#include "clang/AST/ExprCXX.h"
22#include "clang/AST/ExprObjC.h"
23#include "clang/AST/RecursiveASTVisitor.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/AST/StmtObjC.h"
26#include "clang/AST/TypeLoc.h"
27#include "clang/AST/TypeOrdering.h"
28#include "clang/Basic/TargetInfo.h"
29#include "clang/Lex/Preprocessor.h"
30#include "clang/Sema/Initialization.h"
31#include "clang/Sema/Lookup.h"
32#include "clang/Sema/Scope.h"
33#include "clang/Sema/ScopeInfo.h"
34#include "llvm/ADT/ArrayRef.h"
35#include "llvm/ADT/DenseMap.h"
36#include "llvm/ADT/STLExtras.h"
37#include "llvm/ADT/SmallPtrSet.h"
38#include "llvm/ADT/SmallString.h"
39#include "llvm/ADT/SmallVector.h"
40using namespace clang;
41using namespace sema;
42
43StmtResult Sema::ActOnExprStmt(ExprResult FE) {
44  if (FE.isInvalid())
45    return StmtError();
46
47  FE = ActOnFinishFullExpr(FE.get(), FE.get()->getExprLoc(),
48                           /*DiscardedValue*/ true);
49  if (FE.isInvalid())
50    return StmtError();
51
52  // C99 6.8.3p2: The expression in an expression statement is evaluated as a
53  // void expression for its side effects.  Conversion to void allows any
54  // operand, even incomplete types.
55
56  // Same thing in for stmt first clause (when expr) and third clause.
57  return StmtResult(FE.getAs<Stmt>());
58}
59
60
61StmtResult Sema::ActOnExprStmtError() {
62  DiscardCleanupsInEvaluationContext();
63  return StmtError();
64}
65
66StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
67                               bool HasLeadingEmptyMacro) {
68  return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
69}
70
71StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
72                               SourceLocation EndLoc) {
73  DeclGroupRef DG = dg.get();
74
75  // If we have an invalid decl, just return an error.
76  if (DG.isNull()) return StmtError();
77
78  return new (Context) DeclStmt(DG, StartLoc, EndLoc);
79}
80
81void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
82  DeclGroupRef DG = dg.get();
83
84  // If we don't have a declaration, or we have an invalid declaration,
85  // just return.
86  if (DG.isNull() || !DG.isSingleDecl())
87    return;
88
89  Decl *decl = DG.getSingleDecl();
90  if (!decl || decl->isInvalidDecl())
91    return;
92
93  // Only variable declarations are permitted.
94  VarDecl *var = dyn_cast<VarDecl>(decl);
95  if (!var) {
96    Diag(decl->getLocation(), diag::err_non_variable_decl_in_for);
97    decl->setInvalidDecl();
98    return;
99  }
100
101  // foreach variables are never actually initialized in the way that
102  // the parser came up with.
103  var->setInit(nullptr);
104
105  // In ARC, we don't need to retain the iteration variable of a fast
106  // enumeration loop.  Rather than actually trying to catch that
107  // during declaration processing, we remove the consequences here.
108  if (getLangOpts().ObjCAutoRefCount) {
109    QualType type = var->getType();
110
111    // Only do this if we inferred the lifetime.  Inferred lifetime
112    // will show up as a local qualifier because explicit lifetime
113    // should have shown up as an AttributedType instead.
114    if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
115      // Add 'const' and mark the variable as pseudo-strong.
116      var->setType(type.withConst());
117      var->setARCPseudoStrong(true);
118    }
119  }
120}
121
122/// \brief Diagnose unused comparisons, both builtin and overloaded operators.
123/// For '==' and '!=', suggest fixits for '=' or '|='.
124///
125/// Adding a cast to void (or other expression wrappers) will prevent the
126/// warning from firing.
127static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
128  SourceLocation Loc;
129  bool IsNotEqual, CanAssign, IsRelational;
130
131  if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
132    if (!Op->isComparisonOp())
133      return false;
134
135    IsRelational = Op->isRelationalOp();
136    Loc = Op->getOperatorLoc();
137    IsNotEqual = Op->getOpcode() == BO_NE;
138    CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
139  } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
140    switch (Op->getOperator()) {
141    default:
142      return false;
143    case OO_EqualEqual:
144    case OO_ExclaimEqual:
145      IsRelational = false;
146      break;
147    case OO_Less:
148    case OO_Greater:
149    case OO_GreaterEqual:
150    case OO_LessEqual:
151      IsRelational = true;
152      break;
153    }
154
155    Loc = Op->getOperatorLoc();
156    IsNotEqual = Op->getOperator() == OO_ExclaimEqual;
157    CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue();
158  } else {
159    // Not a typo-prone comparison.
160    return false;
161  }
162
163  // Suppress warnings when the operator, suspicious as it may be, comes from
164  // a macro expansion.
165  if (S.SourceMgr.isMacroBodyExpansion(Loc))
166    return false;
167
168  S.Diag(Loc, diag::warn_unused_comparison)
169    << (unsigned)IsRelational << (unsigned)IsNotEqual << E->getSourceRange();
170
171  // If the LHS is a plausible entity to assign to, provide a fixit hint to
172  // correct common typos.
173  if (!IsRelational && CanAssign) {
174    if (IsNotEqual)
175      S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
176        << FixItHint::CreateReplacement(Loc, "|=");
177    else
178      S.Diag(Loc, diag::note_equality_comparison_to_assign)
179        << FixItHint::CreateReplacement(Loc, "=");
180  }
181
182  return true;
183}
184
185void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
186  if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
187    return DiagnoseUnusedExprResult(Label->getSubStmt());
188
189  const Expr *E = dyn_cast_or_null<Expr>(S);
190  if (!E)
191    return;
192
193  // If we are in an unevaluated expression context, then there can be no unused
194  // results because the results aren't expected to be used in the first place.
195  if (isUnevaluatedContext())
196    return;
197
198  SourceLocation ExprLoc = E->IgnoreParens()->getExprLoc();
199  // In most cases, we don't want to warn if the expression is written in a
200  // macro body, or if the macro comes from a system header. If the offending
201  // expression is a call to a function with the warn_unused_result attribute,
202  // we warn no matter the location. Because of the order in which the various
203  // checks need to happen, we factor out the macro-related test here.
204  bool ShouldSuppress =
205      SourceMgr.isMacroBodyExpansion(ExprLoc) ||
206      SourceMgr.isInSystemMacro(ExprLoc);
207
208  const Expr *WarnExpr;
209  SourceLocation Loc;
210  SourceRange R1, R2;
211  if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context))
212    return;
213
214  // If this is a GNU statement expression expanded from a macro, it is probably
215  // unused because it is a function-like macro that can be used as either an
216  // expression or statement.  Don't warn, because it is almost certainly a
217  // false positive.
218  if (isa<StmtExpr>(E) && Loc.isMacroID())
219    return;
220
221  // Okay, we have an unused result.  Depending on what the base expression is,
222  // we might want to make a more specific diagnostic.  Check for one of these
223  // cases now.
224  unsigned DiagID = diag::warn_unused_expr;
225  if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E))
226    E = Temps->getSubExpr();
227  if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
228    E = TempExpr->getSubExpr();
229
230  if (DiagnoseUnusedComparison(*this, E))
231    return;
232
233  E = WarnExpr;
234  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
235    if (E->getType()->isVoidType())
236      return;
237
238    // If the callee has attribute pure, const, or warn_unused_result, warn with
239    // a more specific message to make it clear what is happening. If the call
240    // is written in a macro body, only warn if it has the warn_unused_result
241    // attribute.
242    if (const Decl *FD = CE->getCalleeDecl()) {
243      const FunctionDecl *Func = dyn_cast<FunctionDecl>(FD);
244      if (Func ? Func->hasUnusedResultAttr()
245               : FD->hasAttr<WarnUnusedResultAttr>()) {
246        Diag(Loc, diag::warn_unused_result) << R1 << R2;
247        return;
248      }
249      if (ShouldSuppress)
250        return;
251      if (FD->hasAttr<PureAttr>()) {
252        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
253        return;
254      }
255      if (FD->hasAttr<ConstAttr>()) {
256        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
257        return;
258      }
259    }
260  } else if (ShouldSuppress)
261    return;
262
263  if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
264    if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
265      Diag(Loc, diag::err_arc_unused_init_message) << R1;
266      return;
267    }
268    const ObjCMethodDecl *MD = ME->getMethodDecl();
269    if (MD) {
270      if (MD->hasAttr<WarnUnusedResultAttr>()) {
271        Diag(Loc, diag::warn_unused_result) << R1 << R2;
272        return;
273      }
274    }
275  } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
276    const Expr *Source = POE->getSyntacticForm();
277    if (isa<ObjCSubscriptRefExpr>(Source))
278      DiagID = diag::warn_unused_container_subscript_expr;
279    else
280      DiagID = diag::warn_unused_property_expr;
281  } else if (const CXXFunctionalCastExpr *FC
282                                       = dyn_cast<CXXFunctionalCastExpr>(E)) {
283    if (isa<CXXConstructExpr>(FC->getSubExpr()) ||
284        isa<CXXTemporaryObjectExpr>(FC->getSubExpr()))
285      return;
286  }
287  // Diagnose "(void*) blah" as a typo for "(void) blah".
288  else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
289    TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
290    QualType T = TI->getType();
291
292    // We really do want to use the non-canonical type here.
293    if (T == Context.VoidPtrTy) {
294      PointerTypeLoc TL = TI->getTypeLoc().castAs<PointerTypeLoc>();
295
296      Diag(Loc, diag::warn_unused_voidptr)
297        << FixItHint::CreateRemoval(TL.getStarLoc());
298      return;
299    }
300  }
301
302  if (E->isGLValue() && E->getType().isVolatileQualified()) {
303    Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
304    return;
305  }
306
307  DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
308}
309
310void Sema::ActOnStartOfCompoundStmt() {
311  PushCompoundScope();
312}
313
314void Sema::ActOnFinishOfCompoundStmt() {
315  PopCompoundScope();
316}
317
318sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
319  return getCurFunction()->CompoundScopes.back();
320}
321
322StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
323                                   ArrayRef<Stmt *> Elts, bool isStmtExpr) {
324  const unsigned NumElts = Elts.size();
325
326  // If we're in C89 mode, check that we don't have any decls after stmts.  If
327  // so, emit an extension diagnostic.
328  if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) {
329    // Note that __extension__ can be around a decl.
330    unsigned i = 0;
331    // Skip over all declarations.
332    for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
333      /*empty*/;
334
335    // We found the end of the list or a statement.  Scan for another declstmt.
336    for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
337      /*empty*/;
338
339    if (i != NumElts) {
340      Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
341      Diag(D->getLocation(), diag::ext_mixed_decls_code);
342    }
343  }
344  // Warn about unused expressions in statements.
345  for (unsigned i = 0; i != NumElts; ++i) {
346    // Ignore statements that are last in a statement expression.
347    if (isStmtExpr && i == NumElts - 1)
348      continue;
349
350    DiagnoseUnusedExprResult(Elts[i]);
351  }
352
353  // Check for suspicious empty body (null statement) in `for' and `while'
354  // statements.  Don't do anything for template instantiations, this just adds
355  // noise.
356  if (NumElts != 0 && !CurrentInstantiationScope &&
357      getCurCompoundScope().HasEmptyLoopBodies) {
358    for (unsigned i = 0; i != NumElts - 1; ++i)
359      DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]);
360  }
361
362  return new (Context) CompoundStmt(Context, Elts, L, R);
363}
364
365StmtResult
366Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal,
367                    SourceLocation DotDotDotLoc, Expr *RHSVal,
368                    SourceLocation ColonLoc) {
369  assert(LHSVal && "missing expression in case statement");
370
371  if (getCurFunction()->SwitchStack.empty()) {
372    Diag(CaseLoc, diag::err_case_not_in_switch);
373    return StmtError();
374  }
375
376  ExprResult LHS =
377      CorrectDelayedTyposInExpr(LHSVal, [this](class Expr *E) {
378        if (!getLangOpts().CPlusPlus11)
379          return VerifyIntegerConstantExpression(E);
380        if (Expr *CondExpr =
381                getCurFunction()->SwitchStack.back()->getCond()) {
382          QualType CondType = CondExpr->getType();
383          llvm::APSInt TempVal;
384          return CheckConvertedConstantExpression(E, CondType, TempVal,
385                                                        CCEK_CaseValue);
386        }
387        return ExprError();
388      });
389  if (LHS.isInvalid())
390    return StmtError();
391  LHSVal = LHS.get();
392
393  if (!getLangOpts().CPlusPlus11) {
394    // C99 6.8.4.2p3: The expression shall be an integer constant.
395    // However, GCC allows any evaluatable integer expression.
396    if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) {
397      LHSVal = VerifyIntegerConstantExpression(LHSVal).get();
398      if (!LHSVal)
399        return StmtError();
400    }
401
402    // GCC extension: The expression shall be an integer constant.
403
404    if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) {
405      RHSVal = VerifyIntegerConstantExpression(RHSVal).get();
406      // Recover from an error by just forgetting about it.
407    }
408  }
409
410  LHS = ActOnFinishFullExpr(LHSVal, LHSVal->getExprLoc(), false,
411                                 getLangOpts().CPlusPlus11);
412  if (LHS.isInvalid())
413    return StmtError();
414
415  auto RHS = RHSVal ? ActOnFinishFullExpr(RHSVal, RHSVal->getExprLoc(), false,
416                                          getLangOpts().CPlusPlus11)
417                    : ExprResult();
418  if (RHS.isInvalid())
419    return StmtError();
420
421  CaseStmt *CS = new (Context)
422      CaseStmt(LHS.get(), RHS.get(), CaseLoc, DotDotDotLoc, ColonLoc);
423  getCurFunction()->SwitchStack.back()->addSwitchCase(CS);
424  return CS;
425}
426
427/// ActOnCaseStmtBody - This installs a statement as the body of a case.
428void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) {
429  DiagnoseUnusedExprResult(SubStmt);
430
431  CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
432  CS->setSubStmt(SubStmt);
433}
434
435StmtResult
436Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
437                       Stmt *SubStmt, Scope *CurScope) {
438  DiagnoseUnusedExprResult(SubStmt);
439
440  if (getCurFunction()->SwitchStack.empty()) {
441    Diag(DefaultLoc, diag::err_default_not_in_switch);
442    return SubStmt;
443  }
444
445  DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
446  getCurFunction()->SwitchStack.back()->addSwitchCase(DS);
447  return DS;
448}
449
450StmtResult
451Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
452                     SourceLocation ColonLoc, Stmt *SubStmt) {
453  // If the label was multiply defined, reject it now.
454  if (TheDecl->getStmt()) {
455    Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
456    Diag(TheDecl->getLocation(), diag::note_previous_definition);
457    return SubStmt;
458  }
459
460  // Otherwise, things are good.  Fill in the declaration and return it.
461  LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
462  TheDecl->setStmt(LS);
463  if (!TheDecl->isGnuLocal()) {
464    TheDecl->setLocStart(IdentLoc);
465    if (!TheDecl->isMSAsmLabel()) {
466      // Don't update the location of MS ASM labels.  These will result in
467      // a diagnostic, and changing the location here will mess that up.
468      TheDecl->setLocation(IdentLoc);
469    }
470  }
471  return LS;
472}
473
474StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc,
475                                     ArrayRef<const Attr*> Attrs,
476                                     Stmt *SubStmt) {
477  // Fill in the declaration and return it.
478  AttributedStmt *LS = AttributedStmt::Create(Context, AttrLoc, Attrs, SubStmt);
479  return LS;
480}
481
482StmtResult
483Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
484                  Stmt *thenStmt, SourceLocation ElseLoc,
485                  Stmt *elseStmt) {
486  // If the condition was invalid, discard the if statement.  We could recover
487  // better by replacing it with a valid expr, but don't do that yet.
488  if (!CondVal.get() && !CondVar) {
489    getCurFunction()->setHasDroppedStmt();
490    return StmtError();
491  }
492
493  ExprResult CondResult(CondVal.release());
494
495  VarDecl *ConditionVar = nullptr;
496  if (CondVar) {
497    ConditionVar = cast<VarDecl>(CondVar);
498    CondResult = CheckConditionVariable(ConditionVar, IfLoc, true);
499    CondResult = ActOnFinishFullExpr(CondResult.get(), IfLoc);
500    if (CondResult.isInvalid())
501      return StmtError();
502  }
503  Expr *ConditionExpr = CondResult.getAs<Expr>();
504  if (!ConditionExpr)
505    return StmtError();
506
507  DiagnoseUnusedExprResult(thenStmt);
508
509  if (!elseStmt) {
510    DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt,
511                          diag::warn_empty_if_body);
512  }
513
514  DiagnoseUnusedExprResult(elseStmt);
515
516  return new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
517                              thenStmt, ElseLoc, elseStmt);
518}
519
520namespace {
521  struct CaseCompareFunctor {
522    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
523                    const llvm::APSInt &RHS) {
524      return LHS.first < RHS;
525    }
526    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
527                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
528      return LHS.first < RHS.first;
529    }
530    bool operator()(const llvm::APSInt &LHS,
531                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
532      return LHS < RHS.first;
533    }
534  };
535}
536
537/// CmpCaseVals - Comparison predicate for sorting case values.
538///
539static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
540                        const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
541  if (lhs.first < rhs.first)
542    return true;
543
544  if (lhs.first == rhs.first &&
545      lhs.second->getCaseLoc().getRawEncoding()
546       < rhs.second->getCaseLoc().getRawEncoding())
547    return true;
548  return false;
549}
550
551/// CmpEnumVals - Comparison predicate for sorting enumeration values.
552///
553static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
554                        const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
555{
556  return lhs.first < rhs.first;
557}
558
559/// EqEnumVals - Comparison preficate for uniqing enumeration values.
560///
561static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
562                       const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
563{
564  return lhs.first == rhs.first;
565}
566
567/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
568/// potentially integral-promoted expression @p expr.
569static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) {
570  if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr))
571    expr = cleanups->getSubExpr();
572  while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) {
573    if (impcast->getCastKind() != CK_IntegralCast) break;
574    expr = impcast->getSubExpr();
575  }
576  return expr->getType();
577}
578
579StmtResult
580Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
581                             Decl *CondVar) {
582  ExprResult CondResult;
583
584  VarDecl *ConditionVar = nullptr;
585  if (CondVar) {
586    ConditionVar = cast<VarDecl>(CondVar);
587    CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false);
588    if (CondResult.isInvalid())
589      return StmtError();
590
591    Cond = CondResult.get();
592  }
593
594  if (!Cond)
595    return StmtError();
596
597  class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
598    Expr *Cond;
599
600  public:
601    SwitchConvertDiagnoser(Expr *Cond)
602        : ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
603          Cond(Cond) {}
604
605    SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
606                                         QualType T) override {
607      return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
608    }
609
610    SemaDiagnosticBuilder diagnoseIncomplete(
611        Sema &S, SourceLocation Loc, QualType T) override {
612      return S.Diag(Loc, diag::err_switch_incomplete_class_type)
613               << T << Cond->getSourceRange();
614    }
615
616    SemaDiagnosticBuilder diagnoseExplicitConv(
617        Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
618      return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
619    }
620
621    SemaDiagnosticBuilder noteExplicitConv(
622        Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
623      return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
624        << ConvTy->isEnumeralType() << ConvTy;
625    }
626
627    SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
628                                            QualType T) override {
629      return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
630    }
631
632    SemaDiagnosticBuilder noteAmbiguous(
633        Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
634      return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
635      << ConvTy->isEnumeralType() << ConvTy;
636    }
637
638    SemaDiagnosticBuilder diagnoseConversion(
639        Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
640      llvm_unreachable("conversion functions are permitted");
641    }
642  } SwitchDiagnoser(Cond);
643
644  CondResult =
645      PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
646  if (CondResult.isInvalid()) return StmtError();
647  Cond = CondResult.get();
648
649  // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
650  CondResult = UsualUnaryConversions(Cond);
651  if (CondResult.isInvalid()) return StmtError();
652  Cond = CondResult.get();
653
654  CondResult = ActOnFinishFullExpr(Cond, SwitchLoc);
655  if (CondResult.isInvalid())
656    return StmtError();
657  Cond = CondResult.get();
658
659  getCurFunction()->setHasBranchIntoScope();
660
661  SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond);
662  getCurFunction()->SwitchStack.push_back(SS);
663  return SS;
664}
665
666static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
667  Val = Val.extOrTrunc(BitWidth);
668  Val.setIsSigned(IsSigned);
669}
670
671/// Check the specified case value is in range for the given unpromoted switch
672/// type.
673static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
674                           unsigned UnpromotedWidth, bool UnpromotedSign) {
675  // If the case value was signed and negative and the switch expression is
676  // unsigned, don't bother to warn: this is implementation-defined behavior.
677  // FIXME: Introduce a second, default-ignored warning for this case?
678  if (UnpromotedWidth < Val.getBitWidth()) {
679    llvm::APSInt ConvVal(Val);
680    AdjustAPSInt(ConvVal, UnpromotedWidth, UnpromotedSign);
681    AdjustAPSInt(ConvVal, Val.getBitWidth(), Val.isSigned());
682    // FIXME: Use different diagnostics for overflow  in conversion to promoted
683    // type versus "switch expression cannot have this value". Use proper
684    // IntRange checking rather than just looking at the unpromoted type here.
685    if (ConvVal != Val)
686      S.Diag(Loc, diag::warn_case_value_overflow) << Val.toString(10)
687                                                  << ConvVal.toString(10);
688  }
689}
690
691typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
692
693/// Returns true if we should emit a diagnostic about this case expression not
694/// being a part of the enum used in the switch controlling expression.
695static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
696                                              const EnumDecl *ED,
697                                              const Expr *CaseExpr,
698                                              EnumValsTy::iterator &EI,
699                                              EnumValsTy::iterator &EIEnd,
700                                              const llvm::APSInt &Val) {
701  bool FlagType = ED->hasAttr<FlagEnumAttr>();
702
703  if (const DeclRefExpr *DRE =
704          dyn_cast<DeclRefExpr>(CaseExpr->IgnoreParenImpCasts())) {
705    if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
706      QualType VarType = VD->getType();
707      QualType EnumType = S.Context.getTypeDeclType(ED);
708      if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
709          S.Context.hasSameUnqualifiedType(EnumType, VarType))
710        return false;
711    }
712  }
713
714  if (FlagType) {
715    return !S.IsValueInFlagEnum(ED, Val, false);
716  } else {
717    while (EI != EIEnd && EI->first < Val)
718      EI++;
719
720    if (EI != EIEnd && EI->first == Val)
721      return false;
722  }
723
724  return true;
725}
726
727StmtResult
728Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
729                            Stmt *BodyStmt) {
730  SwitchStmt *SS = cast<SwitchStmt>(Switch);
731  assert(SS == getCurFunction()->SwitchStack.back() &&
732         "switch stack missing push/pop!");
733
734  getCurFunction()->SwitchStack.pop_back();
735
736  if (!BodyStmt) return StmtError();
737  SS->setBody(BodyStmt, SwitchLoc);
738
739  Expr *CondExpr = SS->getCond();
740  if (!CondExpr) return StmtError();
741
742  QualType CondType = CondExpr->getType();
743
744  Expr *CondExprBeforePromotion = CondExpr;
745  QualType CondTypeBeforePromotion =
746      GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
747
748  // C++ 6.4.2.p2:
749  // Integral promotions are performed (on the switch condition).
750  //
751  // A case value unrepresentable by the original switch condition
752  // type (before the promotion) doesn't make sense, even when it can
753  // be represented by the promoted type.  Therefore we need to find
754  // the pre-promotion type of the switch condition.
755  if (!CondExpr->isTypeDependent()) {
756    // We have already converted the expression to an integral or enumeration
757    // type, when we started the switch statement. If we don't have an
758    // appropriate type now, just return an error.
759    if (!CondType->isIntegralOrEnumerationType())
760      return StmtError();
761
762    if (CondExpr->isKnownToHaveBooleanValue()) {
763      // switch(bool_expr) {...} is often a programmer error, e.g.
764      //   switch(n && mask) { ... }  // Doh - should be "n & mask".
765      // One can always use an if statement instead of switch(bool_expr).
766      Diag(SwitchLoc, diag::warn_bool_switch_condition)
767          << CondExpr->getSourceRange();
768    }
769  }
770
771  // Get the bitwidth of the switched-on value after promotions. We must
772  // convert the integer case values to this width before comparison.
773  bool HasDependentValue
774    = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
775  unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(CondType);
776  bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
777
778  // Get the width and signedness that the condition might actually have, for
779  // warning purposes.
780  // FIXME: Grab an IntRange for the condition rather than using the unpromoted
781  // type.
782  unsigned CondWidthBeforePromotion
783    = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion);
784  bool CondIsSignedBeforePromotion
785    = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
786
787  // Accumulate all of the case values in a vector so that we can sort them
788  // and detect duplicates.  This vector contains the APInt for the case after
789  // it has been converted to the condition type.
790  typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
791  CaseValsTy CaseVals;
792
793  // Keep track of any GNU case ranges we see.  The APSInt is the low value.
794  typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
795  CaseRangesTy CaseRanges;
796
797  DefaultStmt *TheDefaultStmt = nullptr;
798
799  bool CaseListIsErroneous = false;
800
801  for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
802       SC = SC->getNextSwitchCase()) {
803
804    if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
805      if (TheDefaultStmt) {
806        Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
807        Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
808
809        // FIXME: Remove the default statement from the switch block so that
810        // we'll return a valid AST.  This requires recursing down the AST and
811        // finding it, not something we are set up to do right now.  For now,
812        // just lop the entire switch stmt out of the AST.
813        CaseListIsErroneous = true;
814      }
815      TheDefaultStmt = DS;
816
817    } else {
818      CaseStmt *CS = cast<CaseStmt>(SC);
819
820      Expr *Lo = CS->getLHS();
821
822      if (Lo->isTypeDependent() || Lo->isValueDependent()) {
823        HasDependentValue = true;
824        break;
825      }
826
827      llvm::APSInt LoVal;
828
829      if (getLangOpts().CPlusPlus11) {
830        // C++11 [stmt.switch]p2: the constant-expression shall be a converted
831        // constant expression of the promoted type of the switch condition.
832        ExprResult ConvLo =
833          CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue);
834        if (ConvLo.isInvalid()) {
835          CaseListIsErroneous = true;
836          continue;
837        }
838        Lo = ConvLo.get();
839      } else {
840        // We already verified that the expression has a i-c-e value (C99
841        // 6.8.4.2p3) - get that value now.
842        LoVal = Lo->EvaluateKnownConstInt(Context);
843
844        // If the LHS is not the same type as the condition, insert an implicit
845        // cast.
846        Lo = DefaultLvalueConversion(Lo).get();
847        Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).get();
848      }
849
850      // Check the unconverted value is within the range of possible values of
851      // the switch expression.
852      checkCaseValue(*this, Lo->getLocStart(), LoVal,
853                     CondWidthBeforePromotion, CondIsSignedBeforePromotion);
854
855      // Convert the value to the same width/sign as the condition.
856      AdjustAPSInt(LoVal, CondWidth, CondIsSigned);
857
858      CS->setLHS(Lo);
859
860      // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
861      if (CS->getRHS()) {
862        if (CS->getRHS()->isTypeDependent() ||
863            CS->getRHS()->isValueDependent()) {
864          HasDependentValue = true;
865          break;
866        }
867        CaseRanges.push_back(std::make_pair(LoVal, CS));
868      } else
869        CaseVals.push_back(std::make_pair(LoVal, CS));
870    }
871  }
872
873  if (!HasDependentValue) {
874    // If we don't have a default statement, check whether the
875    // condition is constant.
876    llvm::APSInt ConstantCondValue;
877    bool HasConstantCond = false;
878    if (!HasDependentValue && !TheDefaultStmt) {
879      HasConstantCond = CondExpr->EvaluateAsInt(ConstantCondValue, Context,
880                                                Expr::SE_AllowSideEffects);
881      assert(!HasConstantCond ||
882             (ConstantCondValue.getBitWidth() == CondWidth &&
883              ConstantCondValue.isSigned() == CondIsSigned));
884    }
885    bool ShouldCheckConstantCond = HasConstantCond;
886
887    // Sort all the scalar case values so we can easily detect duplicates.
888    std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
889
890    if (!CaseVals.empty()) {
891      for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
892        if (ShouldCheckConstantCond &&
893            CaseVals[i].first == ConstantCondValue)
894          ShouldCheckConstantCond = false;
895
896        if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
897          // If we have a duplicate, report it.
898          // First, determine if either case value has a name
899          StringRef PrevString, CurrString;
900          Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
901          Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
902          if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) {
903            PrevString = DeclRef->getDecl()->getName();
904          }
905          if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) {
906            CurrString = DeclRef->getDecl()->getName();
907          }
908          SmallString<16> CaseValStr;
909          CaseVals[i-1].first.toString(CaseValStr);
910
911          if (PrevString == CurrString)
912            Diag(CaseVals[i].second->getLHS()->getLocStart(),
913                 diag::err_duplicate_case) <<
914                 (PrevString.empty() ? StringRef(CaseValStr) : PrevString);
915          else
916            Diag(CaseVals[i].second->getLHS()->getLocStart(),
917                 diag::err_duplicate_case_differing_expr) <<
918                 (PrevString.empty() ? StringRef(CaseValStr) : PrevString) <<
919                 (CurrString.empty() ? StringRef(CaseValStr) : CurrString) <<
920                 CaseValStr;
921
922          Diag(CaseVals[i-1].second->getLHS()->getLocStart(),
923               diag::note_duplicate_case_prev);
924          // FIXME: We really want to remove the bogus case stmt from the
925          // substmt, but we have no way to do this right now.
926          CaseListIsErroneous = true;
927        }
928      }
929    }
930
931    // Detect duplicate case ranges, which usually don't exist at all in
932    // the first place.
933    if (!CaseRanges.empty()) {
934      // Sort all the case ranges by their low value so we can easily detect
935      // overlaps between ranges.
936      std::stable_sort(CaseRanges.begin(), CaseRanges.end());
937
938      // Scan the ranges, computing the high values and removing empty ranges.
939      std::vector<llvm::APSInt> HiVals;
940      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
941        llvm::APSInt &LoVal = CaseRanges[i].first;
942        CaseStmt *CR = CaseRanges[i].second;
943        Expr *Hi = CR->getRHS();
944        llvm::APSInt HiVal;
945
946        if (getLangOpts().CPlusPlus11) {
947          // C++11 [stmt.switch]p2: the constant-expression shall be a converted
948          // constant expression of the promoted type of the switch condition.
949          ExprResult ConvHi =
950            CheckConvertedConstantExpression(Hi, CondType, HiVal,
951                                             CCEK_CaseValue);
952          if (ConvHi.isInvalid()) {
953            CaseListIsErroneous = true;
954            continue;
955          }
956          Hi = ConvHi.get();
957        } else {
958          HiVal = Hi->EvaluateKnownConstInt(Context);
959
960          // If the RHS is not the same type as the condition, insert an
961          // implicit cast.
962          Hi = DefaultLvalueConversion(Hi).get();
963          Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).get();
964        }
965
966        // Check the unconverted value is within the range of possible values of
967        // the switch expression.
968        checkCaseValue(*this, Hi->getLocStart(), HiVal,
969                       CondWidthBeforePromotion, CondIsSignedBeforePromotion);
970
971        // Convert the value to the same width/sign as the condition.
972        AdjustAPSInt(HiVal, CondWidth, CondIsSigned);
973
974        CR->setRHS(Hi);
975
976        // If the low value is bigger than the high value, the case is empty.
977        if (LoVal > HiVal) {
978          Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
979            << SourceRange(CR->getLHS()->getLocStart(),
980                           Hi->getLocEnd());
981          CaseRanges.erase(CaseRanges.begin()+i);
982          --i, --e;
983          continue;
984        }
985
986        if (ShouldCheckConstantCond &&
987            LoVal <= ConstantCondValue &&
988            ConstantCondValue <= HiVal)
989          ShouldCheckConstantCond = false;
990
991        HiVals.push_back(HiVal);
992      }
993
994      // Rescan the ranges, looking for overlap with singleton values and other
995      // ranges.  Since the range list is sorted, we only need to compare case
996      // ranges with their neighbors.
997      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
998        llvm::APSInt &CRLo = CaseRanges[i].first;
999        llvm::APSInt &CRHi = HiVals[i];
1000        CaseStmt *CR = CaseRanges[i].second;
1001
1002        // Check to see whether the case range overlaps with any
1003        // singleton cases.
1004        CaseStmt *OverlapStmt = nullptr;
1005        llvm::APSInt OverlapVal(32);
1006
1007        // Find the smallest value >= the lower bound.  If I is in the
1008        // case range, then we have overlap.
1009        CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
1010                                                  CaseVals.end(), CRLo,
1011                                                  CaseCompareFunctor());
1012        if (I != CaseVals.end() && I->first < CRHi) {
1013          OverlapVal  = I->first;   // Found overlap with scalar.
1014          OverlapStmt = I->second;
1015        }
1016
1017        // Find the smallest value bigger than the upper bound.
1018        I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
1019        if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1020          OverlapVal  = (I-1)->first;      // Found overlap with scalar.
1021          OverlapStmt = (I-1)->second;
1022        }
1023
1024        // Check to see if this case stmt overlaps with the subsequent
1025        // case range.
1026        if (i && CRLo <= HiVals[i-1]) {
1027          OverlapVal  = HiVals[i-1];       // Found overlap with range.
1028          OverlapStmt = CaseRanges[i-1].second;
1029        }
1030
1031        if (OverlapStmt) {
1032          // If we have a duplicate, report it.
1033          Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
1034            << OverlapVal.toString(10);
1035          Diag(OverlapStmt->getLHS()->getLocStart(),
1036               diag::note_duplicate_case_prev);
1037          // FIXME: We really want to remove the bogus case stmt from the
1038          // substmt, but we have no way to do this right now.
1039          CaseListIsErroneous = true;
1040        }
1041      }
1042    }
1043
1044    // Complain if we have a constant condition and we didn't find a match.
1045    if (!CaseListIsErroneous && ShouldCheckConstantCond) {
1046      // TODO: it would be nice if we printed enums as enums, chars as
1047      // chars, etc.
1048      Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
1049        << ConstantCondValue.toString(10)
1050        << CondExpr->getSourceRange();
1051    }
1052
1053    // Check to see if switch is over an Enum and handles all of its
1054    // values.  We only issue a warning if there is not 'default:', but
1055    // we still do the analysis to preserve this information in the AST
1056    // (which can be used by flow-based analyes).
1057    //
1058    const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
1059
1060    // If switch has default case, then ignore it.
1061    if (!CaseListIsErroneous  && !HasConstantCond && ET) {
1062      const EnumDecl *ED = ET->getDecl();
1063      EnumValsTy EnumVals;
1064
1065      // Gather all enum values, set their type and sort them,
1066      // allowing easier comparison with CaseVals.
1067      for (auto *EDI : ED->enumerators()) {
1068        llvm::APSInt Val = EDI->getInitVal();
1069        AdjustAPSInt(Val, CondWidth, CondIsSigned);
1070        EnumVals.push_back(std::make_pair(Val, EDI));
1071      }
1072      std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
1073      auto EI = EnumVals.begin(), EIEnd =
1074        std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1075
1076      // See which case values aren't in enum.
1077      for (CaseValsTy::const_iterator CI = CaseVals.begin();
1078          CI != CaseVals.end(); CI++) {
1079        Expr *CaseExpr = CI->second->getLHS();
1080        if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1081                                              CI->first))
1082          Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1083            << CondTypeBeforePromotion;
1084      }
1085
1086      // See which of case ranges aren't in enum
1087      EI = EnumVals.begin();
1088      for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1089          RI != CaseRanges.end(); RI++) {
1090        Expr *CaseExpr = RI->second->getLHS();
1091        if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1092                                              RI->first))
1093          Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1094            << CondTypeBeforePromotion;
1095
1096        llvm::APSInt Hi =
1097          RI->second->getRHS()->EvaluateKnownConstInt(Context);
1098        AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1099
1100        CaseExpr = RI->second->getRHS();
1101        if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1102                                              Hi))
1103          Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1104            << CondTypeBeforePromotion;
1105      }
1106
1107      // Check which enum vals aren't in switch
1108      auto CI = CaseVals.begin();
1109      auto RI = CaseRanges.begin();
1110      bool hasCasesNotInSwitch = false;
1111
1112      SmallVector<DeclarationName,8> UnhandledNames;
1113
1114      for (EI = EnumVals.begin(); EI != EIEnd; EI++){
1115        // Drop unneeded case values
1116        while (CI != CaseVals.end() && CI->first < EI->first)
1117          CI++;
1118
1119        if (CI != CaseVals.end() && CI->first == EI->first)
1120          continue;
1121
1122        // Drop unneeded case ranges
1123        for (; RI != CaseRanges.end(); RI++) {
1124          llvm::APSInt Hi =
1125            RI->second->getRHS()->EvaluateKnownConstInt(Context);
1126          AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1127          if (EI->first <= Hi)
1128            break;
1129        }
1130
1131        if (RI == CaseRanges.end() || EI->first < RI->first) {
1132          hasCasesNotInSwitch = true;
1133          UnhandledNames.push_back(EI->second->getDeclName());
1134        }
1135      }
1136
1137      if (TheDefaultStmt && UnhandledNames.empty())
1138        Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
1139
1140      // Produce a nice diagnostic if multiple values aren't handled.
1141      if (!UnhandledNames.empty()) {
1142        DiagnosticBuilder DB = Diag(CondExpr->getExprLoc(),
1143                                    TheDefaultStmt ? diag::warn_def_missing_case
1144                                                   : diag::warn_missing_case)
1145                               << (int)UnhandledNames.size();
1146
1147        for (size_t I = 0, E = std::min(UnhandledNames.size(), (size_t)3);
1148             I != E; ++I)
1149          DB << UnhandledNames[I];
1150      }
1151
1152      if (!hasCasesNotInSwitch)
1153        SS->setAllEnumCasesCovered();
1154    }
1155  }
1156
1157  if (BodyStmt)
1158    DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt,
1159                          diag::warn_empty_switch_body);
1160
1161  // FIXME: If the case list was broken is some way, we don't have a good system
1162  // to patch it up.  Instead, just return the whole substmt as broken.
1163  if (CaseListIsErroneous)
1164    return StmtError();
1165
1166  return SS;
1167}
1168
1169void
1170Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1171                             Expr *SrcExpr) {
1172  if (Diags.isIgnored(diag::warn_not_in_enum_assignment, SrcExpr->getExprLoc()))
1173    return;
1174
1175  if (const EnumType *ET = DstType->getAs<EnumType>())
1176    if (!Context.hasSameUnqualifiedType(SrcType, DstType) &&
1177        SrcType->isIntegerType()) {
1178      if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() &&
1179          SrcExpr->isIntegerConstantExpr(Context)) {
1180        // Get the bitwidth of the enum value before promotions.
1181        unsigned DstWidth = Context.getIntWidth(DstType);
1182        bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1183
1184        llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Context);
1185        AdjustAPSInt(RhsVal, DstWidth, DstIsSigned);
1186        const EnumDecl *ED = ET->getDecl();
1187
1188        if (ED->hasAttr<FlagEnumAttr>()) {
1189          if (!IsValueInFlagEnum(ED, RhsVal, true))
1190            Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1191              << DstType.getUnqualifiedType();
1192        } else {
1193          typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl *>, 64>
1194              EnumValsTy;
1195          EnumValsTy EnumVals;
1196
1197          // Gather all enum values, set their type and sort them,
1198          // allowing easier comparison with rhs constant.
1199          for (auto *EDI : ED->enumerators()) {
1200            llvm::APSInt Val = EDI->getInitVal();
1201            AdjustAPSInt(Val, DstWidth, DstIsSigned);
1202            EnumVals.push_back(std::make_pair(Val, EDI));
1203          }
1204          if (EnumVals.empty())
1205            return;
1206          std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
1207          EnumValsTy::iterator EIend =
1208              std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1209
1210          // See which values aren't in the enum.
1211          EnumValsTy::const_iterator EI = EnumVals.begin();
1212          while (EI != EIend && EI->first < RhsVal)
1213            EI++;
1214          if (EI == EIend || EI->first != RhsVal) {
1215            Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1216                << DstType.getUnqualifiedType();
1217          }
1218        }
1219      }
1220    }
1221}
1222
1223StmtResult
1224Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
1225                     Decl *CondVar, Stmt *Body) {
1226  ExprResult CondResult(Cond.release());
1227
1228  VarDecl *ConditionVar = nullptr;
1229  if (CondVar) {
1230    ConditionVar = cast<VarDecl>(CondVar);
1231    CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true);
1232    CondResult = ActOnFinishFullExpr(CondResult.get(), WhileLoc);
1233    if (CondResult.isInvalid())
1234      return StmtError();
1235  }
1236  Expr *ConditionExpr = CondResult.get();
1237  if (!ConditionExpr)
1238    return StmtError();
1239  CheckBreakContinueBinding(ConditionExpr);
1240
1241  DiagnoseUnusedExprResult(Body);
1242
1243  if (isa<NullStmt>(Body))
1244    getCurCompoundScope().setHasEmptyLoopBodies();
1245
1246  return new (Context)
1247      WhileStmt(Context, ConditionVar, ConditionExpr, Body, WhileLoc);
1248}
1249
1250StmtResult
1251Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1252                  SourceLocation WhileLoc, SourceLocation CondLParen,
1253                  Expr *Cond, SourceLocation CondRParen) {
1254  assert(Cond && "ActOnDoStmt(): missing expression");
1255
1256  CheckBreakContinueBinding(Cond);
1257  ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc);
1258  if (CondResult.isInvalid())
1259    return StmtError();
1260  Cond = CondResult.get();
1261
1262  CondResult = ActOnFinishFullExpr(Cond, DoLoc);
1263  if (CondResult.isInvalid())
1264    return StmtError();
1265  Cond = CondResult.get();
1266
1267  DiagnoseUnusedExprResult(Body);
1268
1269  return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1270}
1271
1272namespace {
1273  // This visitor will traverse a conditional statement and store all
1274  // the evaluated decls into a vector.  Simple is set to true if none
1275  // of the excluded constructs are used.
1276  class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1277    llvm::SmallPtrSetImpl<VarDecl*> &Decls;
1278    SmallVectorImpl<SourceRange> &Ranges;
1279    bool Simple;
1280  public:
1281    typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1282
1283    DeclExtractor(Sema &S, llvm::SmallPtrSetImpl<VarDecl*> &Decls,
1284                  SmallVectorImpl<SourceRange> &Ranges) :
1285        Inherited(S.Context),
1286        Decls(Decls),
1287        Ranges(Ranges),
1288        Simple(true) {}
1289
1290    bool isSimple() { return Simple; }
1291
1292    // Replaces the method in EvaluatedExprVisitor.
1293    void VisitMemberExpr(MemberExpr* E) {
1294      Simple = false;
1295    }
1296
1297    // Any Stmt not whitelisted will cause the condition to be marked complex.
1298    void VisitStmt(Stmt *S) {
1299      Simple = false;
1300    }
1301
1302    void VisitBinaryOperator(BinaryOperator *E) {
1303      Visit(E->getLHS());
1304      Visit(E->getRHS());
1305    }
1306
1307    void VisitCastExpr(CastExpr *E) {
1308      Visit(E->getSubExpr());
1309    }
1310
1311    void VisitUnaryOperator(UnaryOperator *E) {
1312      // Skip checking conditionals with derefernces.
1313      if (E->getOpcode() == UO_Deref)
1314        Simple = false;
1315      else
1316        Visit(E->getSubExpr());
1317    }
1318
1319    void VisitConditionalOperator(ConditionalOperator *E) {
1320      Visit(E->getCond());
1321      Visit(E->getTrueExpr());
1322      Visit(E->getFalseExpr());
1323    }
1324
1325    void VisitParenExpr(ParenExpr *E) {
1326      Visit(E->getSubExpr());
1327    }
1328
1329    void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1330      Visit(E->getOpaqueValue()->getSourceExpr());
1331      Visit(E->getFalseExpr());
1332    }
1333
1334    void VisitIntegerLiteral(IntegerLiteral *E) { }
1335    void VisitFloatingLiteral(FloatingLiteral *E) { }
1336    void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1337    void VisitCharacterLiteral(CharacterLiteral *E) { }
1338    void VisitGNUNullExpr(GNUNullExpr *E) { }
1339    void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1340
1341    void VisitDeclRefExpr(DeclRefExpr *E) {
1342      VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
1343      if (!VD) return;
1344
1345      Ranges.push_back(E->getSourceRange());
1346
1347      Decls.insert(VD);
1348    }
1349
1350  }; // end class DeclExtractor
1351
1352  // DeclMatcher checks to see if the decls are used in a non-evauluated
1353  // context.
1354  class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1355    llvm::SmallPtrSetImpl<VarDecl*> &Decls;
1356    bool FoundDecl;
1357
1358  public:
1359    typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1360
1361    DeclMatcher(Sema &S, llvm::SmallPtrSetImpl<VarDecl*> &Decls,
1362                Stmt *Statement) :
1363        Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1364      if (!Statement) return;
1365
1366      Visit(Statement);
1367    }
1368
1369    void VisitReturnStmt(ReturnStmt *S) {
1370      FoundDecl = true;
1371    }
1372
1373    void VisitBreakStmt(BreakStmt *S) {
1374      FoundDecl = true;
1375    }
1376
1377    void VisitGotoStmt(GotoStmt *S) {
1378      FoundDecl = true;
1379    }
1380
1381    void VisitCastExpr(CastExpr *E) {
1382      if (E->getCastKind() == CK_LValueToRValue)
1383        CheckLValueToRValueCast(E->getSubExpr());
1384      else
1385        Visit(E->getSubExpr());
1386    }
1387
1388    void CheckLValueToRValueCast(Expr *E) {
1389      E = E->IgnoreParenImpCasts();
1390
1391      if (isa<DeclRefExpr>(E)) {
1392        return;
1393      }
1394
1395      if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
1396        Visit(CO->getCond());
1397        CheckLValueToRValueCast(CO->getTrueExpr());
1398        CheckLValueToRValueCast(CO->getFalseExpr());
1399        return;
1400      }
1401
1402      if (BinaryConditionalOperator *BCO =
1403              dyn_cast<BinaryConditionalOperator>(E)) {
1404        CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr());
1405        CheckLValueToRValueCast(BCO->getFalseExpr());
1406        return;
1407      }
1408
1409      Visit(E);
1410    }
1411
1412    void VisitDeclRefExpr(DeclRefExpr *E) {
1413      if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
1414        if (Decls.count(VD))
1415          FoundDecl = true;
1416    }
1417
1418    bool FoundDeclInUse() { return FoundDecl; }
1419
1420  };  // end class DeclMatcher
1421
1422  void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
1423                                        Expr *Third, Stmt *Body) {
1424    // Condition is empty
1425    if (!Second) return;
1426
1427    if (S.Diags.isIgnored(diag::warn_variables_not_in_loop_body,
1428                          Second->getLocStart()))
1429      return;
1430
1431    PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
1432    llvm::SmallPtrSet<VarDecl*, 8> Decls;
1433    SmallVector<SourceRange, 10> Ranges;
1434    DeclExtractor DE(S, Decls, Ranges);
1435    DE.Visit(Second);
1436
1437    // Don't analyze complex conditionals.
1438    if (!DE.isSimple()) return;
1439
1440    // No decls found.
1441    if (Decls.size() == 0) return;
1442
1443    // Don't warn on volatile, static, or global variables.
1444    for (llvm::SmallPtrSetImpl<VarDecl*>::iterator I = Decls.begin(),
1445                                                   E = Decls.end();
1446         I != E; ++I)
1447      if ((*I)->getType().isVolatileQualified() ||
1448          (*I)->hasGlobalStorage()) return;
1449
1450    if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
1451        DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
1452        DeclMatcher(S, Decls, Body).FoundDeclInUse())
1453      return;
1454
1455    // Load decl names into diagnostic.
1456    if (Decls.size() > 4)
1457      PDiag << 0;
1458    else {
1459      PDiag << Decls.size();
1460      for (llvm::SmallPtrSetImpl<VarDecl*>::iterator I = Decls.begin(),
1461                                                     E = Decls.end();
1462           I != E; ++I)
1463        PDiag << (*I)->getDeclName();
1464    }
1465
1466    // Load SourceRanges into diagnostic if there is room.
1467    // Otherwise, load the SourceRange of the conditional expression.
1468    if (Ranges.size() <= PartialDiagnostic::MaxArguments)
1469      for (SmallVectorImpl<SourceRange>::iterator I = Ranges.begin(),
1470                                                  E = Ranges.end();
1471           I != E; ++I)
1472        PDiag << *I;
1473    else
1474      PDiag << Second->getSourceRange();
1475
1476    S.Diag(Ranges.begin()->getBegin(), PDiag);
1477  }
1478
1479  // If Statement is an incemement or decrement, return true and sets the
1480  // variables Increment and DRE.
1481  bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
1482                            DeclRefExpr *&DRE) {
1483    if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Statement)) {
1484      switch (UO->getOpcode()) {
1485        default: return false;
1486        case UO_PostInc:
1487        case UO_PreInc:
1488          Increment = true;
1489          break;
1490        case UO_PostDec:
1491        case UO_PreDec:
1492          Increment = false;
1493          break;
1494      }
1495      DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr());
1496      return DRE;
1497    }
1498
1499    if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Statement)) {
1500      FunctionDecl *FD = Call->getDirectCallee();
1501      if (!FD || !FD->isOverloadedOperator()) return false;
1502      switch (FD->getOverloadedOperator()) {
1503        default: return false;
1504        case OO_PlusPlus:
1505          Increment = true;
1506          break;
1507        case OO_MinusMinus:
1508          Increment = false;
1509          break;
1510      }
1511      DRE = dyn_cast<DeclRefExpr>(Call->getArg(0));
1512      return DRE;
1513    }
1514
1515    return false;
1516  }
1517
1518  // A visitor to determine if a continue or break statement is a
1519  // subexpression.
1520  class BreakContinueFinder : public EvaluatedExprVisitor<BreakContinueFinder> {
1521    SourceLocation BreakLoc;
1522    SourceLocation ContinueLoc;
1523  public:
1524    BreakContinueFinder(Sema &S, Stmt* Body) :
1525        Inherited(S.Context) {
1526      Visit(Body);
1527    }
1528
1529    typedef EvaluatedExprVisitor<BreakContinueFinder> Inherited;
1530
1531    void VisitContinueStmt(ContinueStmt* E) {
1532      ContinueLoc = E->getContinueLoc();
1533    }
1534
1535    void VisitBreakStmt(BreakStmt* E) {
1536      BreakLoc = E->getBreakLoc();
1537    }
1538
1539    bool ContinueFound() { return ContinueLoc.isValid(); }
1540    bool BreakFound() { return BreakLoc.isValid(); }
1541    SourceLocation GetContinueLoc() { return ContinueLoc; }
1542    SourceLocation GetBreakLoc() { return BreakLoc; }
1543
1544  };  // end class BreakContinueFinder
1545
1546  // Emit a warning when a loop increment/decrement appears twice per loop
1547  // iteration.  The conditions which trigger this warning are:
1548  // 1) The last statement in the loop body and the third expression in the
1549  //    for loop are both increment or both decrement of the same variable
1550  // 2) No continue statements in the loop body.
1551  void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
1552    // Return when there is nothing to check.
1553    if (!Body || !Third) return;
1554
1555    if (S.Diags.isIgnored(diag::warn_redundant_loop_iteration,
1556                          Third->getLocStart()))
1557      return;
1558
1559    // Get the last statement from the loop body.
1560    CompoundStmt *CS = dyn_cast<CompoundStmt>(Body);
1561    if (!CS || CS->body_empty()) return;
1562    Stmt *LastStmt = CS->body_back();
1563    if (!LastStmt) return;
1564
1565    bool LoopIncrement, LastIncrement;
1566    DeclRefExpr *LoopDRE, *LastDRE;
1567
1568    if (!ProcessIterationStmt(S, Third, LoopIncrement, LoopDRE)) return;
1569    if (!ProcessIterationStmt(S, LastStmt, LastIncrement, LastDRE)) return;
1570
1571    // Check that the two statements are both increments or both decrements
1572    // on the same variable.
1573    if (LoopIncrement != LastIncrement ||
1574        LoopDRE->getDecl() != LastDRE->getDecl()) return;
1575
1576    if (BreakContinueFinder(S, Body).ContinueFound()) return;
1577
1578    S.Diag(LastDRE->getLocation(), diag::warn_redundant_loop_iteration)
1579         << LastDRE->getDecl() << LastIncrement;
1580    S.Diag(LoopDRE->getLocation(), diag::note_loop_iteration_here)
1581         << LoopIncrement;
1582  }
1583
1584} // end namespace
1585
1586
1587void Sema::CheckBreakContinueBinding(Expr *E) {
1588  if (!E || getLangOpts().CPlusPlus)
1589    return;
1590  BreakContinueFinder BCFinder(*this, E);
1591  Scope *BreakParent = CurScope->getBreakParent();
1592  if (BCFinder.BreakFound() && BreakParent) {
1593    if (BreakParent->getFlags() & Scope::SwitchScope) {
1594      Diag(BCFinder.GetBreakLoc(), diag::warn_break_binds_to_switch);
1595    } else {
1596      Diag(BCFinder.GetBreakLoc(), diag::warn_loop_ctrl_binds_to_inner)
1597          << "break";
1598    }
1599  } else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
1600    Diag(BCFinder.GetContinueLoc(), diag::warn_loop_ctrl_binds_to_inner)
1601        << "continue";
1602  }
1603}
1604
1605StmtResult
1606Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
1607                   Stmt *First, FullExprArg second, Decl *secondVar,
1608                   FullExprArg third,
1609                   SourceLocation RParenLoc, Stmt *Body) {
1610  if (!getLangOpts().CPlusPlus) {
1611    if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
1612      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
1613      // declare identifiers for objects having storage class 'auto' or
1614      // 'register'.
1615      for (auto *DI : DS->decls()) {
1616        VarDecl *VD = dyn_cast<VarDecl>(DI);
1617        if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage())
1618          VD = nullptr;
1619        if (!VD) {
1620          Diag(DI->getLocation(), diag::err_non_local_variable_decl_in_for);
1621          DI->setInvalidDecl();
1622        }
1623      }
1624    }
1625  }
1626
1627  CheckBreakContinueBinding(second.get());
1628  CheckBreakContinueBinding(third.get());
1629
1630  CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body);
1631  CheckForRedundantIteration(*this, third.get(), Body);
1632
1633  ExprResult SecondResult(second.release());
1634  VarDecl *ConditionVar = nullptr;
1635  if (secondVar) {
1636    ConditionVar = cast<VarDecl>(secondVar);
1637    SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true);
1638    SecondResult = ActOnFinishFullExpr(SecondResult.get(), ForLoc);
1639    if (SecondResult.isInvalid())
1640      return StmtError();
1641  }
1642
1643  Expr *Third  = third.release().getAs<Expr>();
1644
1645  DiagnoseUnusedExprResult(First);
1646  DiagnoseUnusedExprResult(Third);
1647  DiagnoseUnusedExprResult(Body);
1648
1649  if (isa<NullStmt>(Body))
1650    getCurCompoundScope().setHasEmptyLoopBodies();
1651
1652  return new (Context) ForStmt(Context, First, SecondResult.get(), ConditionVar,
1653                               Third, Body, ForLoc, LParenLoc, RParenLoc);
1654}
1655
1656/// In an Objective C collection iteration statement:
1657///   for (x in y)
1658/// x can be an arbitrary l-value expression.  Bind it up as a
1659/// full-expression.
1660StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
1661  // Reduce placeholder expressions here.  Note that this rejects the
1662  // use of pseudo-object l-values in this position.
1663  ExprResult result = CheckPlaceholderExpr(E);
1664  if (result.isInvalid()) return StmtError();
1665  E = result.get();
1666
1667  ExprResult FullExpr = ActOnFinishFullExpr(E);
1668  if (FullExpr.isInvalid())
1669    return StmtError();
1670  return StmtResult(static_cast<Stmt*>(FullExpr.get()));
1671}
1672
1673ExprResult
1674Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
1675  if (!collection)
1676    return ExprError();
1677
1678  ExprResult result = CorrectDelayedTyposInExpr(collection);
1679  if (!result.isUsable())
1680    return ExprError();
1681  collection = result.get();
1682
1683  // Bail out early if we've got a type-dependent expression.
1684  if (collection->isTypeDependent()) return collection;
1685
1686  // Perform normal l-value conversion.
1687  result = DefaultFunctionArrayLvalueConversion(collection);
1688  if (result.isInvalid())
1689    return ExprError();
1690  collection = result.get();
1691
1692  // The operand needs to have object-pointer type.
1693  // TODO: should we do a contextual conversion?
1694  const ObjCObjectPointerType *pointerType =
1695    collection->getType()->getAs<ObjCObjectPointerType>();
1696  if (!pointerType)
1697    return Diag(forLoc, diag::err_collection_expr_type)
1698             << collection->getType() << collection->getSourceRange();
1699
1700  // Check that the operand provides
1701  //   - countByEnumeratingWithState:objects:count:
1702  const ObjCObjectType *objectType = pointerType->getObjectType();
1703  ObjCInterfaceDecl *iface = objectType->getInterface();
1704
1705  // If we have a forward-declared type, we can't do this check.
1706  // Under ARC, it is an error not to have a forward-declared class.
1707  if (iface &&
1708      RequireCompleteType(forLoc, QualType(objectType, 0),
1709                          getLangOpts().ObjCAutoRefCount
1710                            ? diag::err_arc_collection_forward
1711                            : 0,
1712                          collection)) {
1713    // Otherwise, if we have any useful type information, check that
1714    // the type declares the appropriate method.
1715  } else if (iface || !objectType->qual_empty()) {
1716    IdentifierInfo *selectorIdents[] = {
1717      &Context.Idents.get("countByEnumeratingWithState"),
1718      &Context.Idents.get("objects"),
1719      &Context.Idents.get("count")
1720    };
1721    Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]);
1722
1723    ObjCMethodDecl *method = nullptr;
1724
1725    // If there's an interface, look in both the public and private APIs.
1726    if (iface) {
1727      method = iface->lookupInstanceMethod(selector);
1728      if (!method) method = iface->lookupPrivateMethod(selector);
1729    }
1730
1731    // Also check protocol qualifiers.
1732    if (!method)
1733      method = LookupMethodInQualifiedType(selector, pointerType,
1734                                           /*instance*/ true);
1735
1736    // If we didn't find it anywhere, give up.
1737    if (!method) {
1738      Diag(forLoc, diag::warn_collection_expr_type)
1739        << collection->getType() << selector << collection->getSourceRange();
1740    }
1741
1742    // TODO: check for an incompatible signature?
1743  }
1744
1745  // Wrap up any cleanups in the expression.
1746  return collection;
1747}
1748
1749StmtResult
1750Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
1751                                 Stmt *First, Expr *collection,
1752                                 SourceLocation RParenLoc) {
1753
1754  ExprResult CollectionExprResult =
1755    CheckObjCForCollectionOperand(ForLoc, collection);
1756
1757  if (First) {
1758    QualType FirstType;
1759    if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
1760      if (!DS->isSingleDecl())
1761        return StmtError(Diag((*DS->decl_begin())->getLocation(),
1762                         diag::err_toomany_element_decls));
1763
1764      VarDecl *D = dyn_cast<VarDecl>(DS->getSingleDecl());
1765      if (!D || D->isInvalidDecl())
1766        return StmtError();
1767
1768      FirstType = D->getType();
1769      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
1770      // declare identifiers for objects having storage class 'auto' or
1771      // 'register'.
1772      if (!D->hasLocalStorage())
1773        return StmtError(Diag(D->getLocation(),
1774                              diag::err_non_local_variable_decl_in_for));
1775
1776      // If the type contained 'auto', deduce the 'auto' to 'id'.
1777      if (FirstType->getContainedAutoType()) {
1778        OpaqueValueExpr OpaqueId(D->getLocation(), Context.getObjCIdType(),
1779                                 VK_RValue);
1780        Expr *DeducedInit = &OpaqueId;
1781        if (DeduceAutoType(D->getTypeSourceInfo(), DeducedInit, FirstType) ==
1782                DAR_Failed)
1783          DiagnoseAutoDeductionFailure(D, DeducedInit);
1784        if (FirstType.isNull()) {
1785          D->setInvalidDecl();
1786          return StmtError();
1787        }
1788
1789        D->setType(FirstType);
1790
1791        if (ActiveTemplateInstantiations.empty()) {
1792          SourceLocation Loc =
1793              D->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
1794          Diag(Loc, diag::warn_auto_var_is_id)
1795            << D->getDeclName();
1796        }
1797      }
1798
1799    } else {
1800      Expr *FirstE = cast<Expr>(First);
1801      if (!FirstE->isTypeDependent() && !FirstE->isLValue())
1802        return StmtError(Diag(First->getLocStart(),
1803                   diag::err_selector_element_not_lvalue)
1804          << First->getSourceRange());
1805
1806      FirstType = static_cast<Expr*>(First)->getType();
1807      if (FirstType.isConstQualified())
1808        Diag(ForLoc, diag::err_selector_element_const_type)
1809          << FirstType << First->getSourceRange();
1810    }
1811    if (!FirstType->isDependentType() &&
1812        !FirstType->isObjCObjectPointerType() &&
1813        !FirstType->isBlockPointerType())
1814        return StmtError(Diag(ForLoc, diag::err_selector_element_type)
1815                           << FirstType << First->getSourceRange());
1816  }
1817
1818  if (CollectionExprResult.isInvalid())
1819    return StmtError();
1820
1821  CollectionExprResult = ActOnFinishFullExpr(CollectionExprResult.get());
1822  if (CollectionExprResult.isInvalid())
1823    return StmtError();
1824
1825  return new (Context) ObjCForCollectionStmt(First, CollectionExprResult.get(),
1826                                             nullptr, ForLoc, RParenLoc);
1827}
1828
1829/// Finish building a variable declaration for a for-range statement.
1830/// \return true if an error occurs.
1831static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
1832                                  SourceLocation Loc, int DiagID) {
1833  if (Decl->getType()->isUndeducedType()) {
1834    ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(Init);
1835    if (!Res.isUsable()) {
1836      Decl->setInvalidDecl();
1837      return true;
1838    }
1839    Init = Res.get();
1840  }
1841
1842  // Deduce the type for the iterator variable now rather than leaving it to
1843  // AddInitializerToDecl, so we can produce a more suitable diagnostic.
1844  QualType InitType;
1845  if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) ||
1846      SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitType) ==
1847          Sema::DAR_Failed)
1848    SemaRef.Diag(Loc, DiagID) << Init->getType();
1849  if (InitType.isNull()) {
1850    Decl->setInvalidDecl();
1851    return true;
1852  }
1853  Decl->setType(InitType);
1854
1855  // In ARC, infer lifetime.
1856  // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
1857  // we're doing the equivalent of fast iteration.
1858  if (SemaRef.getLangOpts().ObjCAutoRefCount &&
1859      SemaRef.inferObjCARCLifetime(Decl))
1860    Decl->setInvalidDecl();
1861
1862  SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false,
1863                               /*TypeMayContainAuto=*/false);
1864  SemaRef.FinalizeDeclaration(Decl);
1865  SemaRef.CurContext->addHiddenDecl(Decl);
1866  return false;
1867}
1868
1869namespace {
1870
1871/// Produce a note indicating which begin/end function was implicitly called
1872/// by a C++11 for-range statement. This is often not obvious from the code,
1873/// nor from the diagnostics produced when analysing the implicit expressions
1874/// required in a for-range statement.
1875void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
1876                                  Sema::BeginEndFunction BEF) {
1877  CallExpr *CE = dyn_cast<CallExpr>(E);
1878  if (!CE)
1879    return;
1880  FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
1881  if (!D)
1882    return;
1883  SourceLocation Loc = D->getLocation();
1884
1885  std::string Description;
1886  bool IsTemplate = false;
1887  if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
1888    Description = SemaRef.getTemplateArgumentBindingsText(
1889      FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
1890    IsTemplate = true;
1891  }
1892
1893  SemaRef.Diag(Loc, diag::note_for_range_begin_end)
1894    << BEF << IsTemplate << Description << E->getType();
1895}
1896
1897/// Build a variable declaration for a for-range statement.
1898VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
1899                              QualType Type, const char *Name) {
1900  DeclContext *DC = SemaRef.CurContext;
1901  IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
1902  TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
1903  VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type,
1904                                  TInfo, SC_None);
1905  Decl->setImplicit();
1906  return Decl;
1907}
1908
1909}
1910
1911static bool ObjCEnumerationCollection(Expr *Collection) {
1912  return !Collection->isTypeDependent()
1913          && Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
1914}
1915
1916/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
1917///
1918/// C++11 [stmt.ranged]:
1919///   A range-based for statement is equivalent to
1920///
1921///   {
1922///     auto && __range = range-init;
1923///     for ( auto __begin = begin-expr,
1924///           __end = end-expr;
1925///           __begin != __end;
1926///           ++__begin ) {
1927///       for-range-declaration = *__begin;
1928///       statement
1929///     }
1930///   }
1931///
1932/// The body of the loop is not available yet, since it cannot be analysed until
1933/// we have determined the type of the for-range-declaration.
1934StmtResult
1935Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc,
1936                           Stmt *First, SourceLocation ColonLoc, Expr *Range,
1937                           SourceLocation RParenLoc, BuildForRangeKind Kind) {
1938  if (!First)
1939    return StmtError();
1940
1941  if (Range && ObjCEnumerationCollection(Range))
1942    return ActOnObjCForCollectionStmt(ForLoc, First, Range, RParenLoc);
1943
1944  DeclStmt *DS = dyn_cast<DeclStmt>(First);
1945  assert(DS && "first part of for range not a decl stmt");
1946
1947  if (!DS->isSingleDecl()) {
1948    Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range);
1949    return StmtError();
1950  }
1951
1952  Decl *LoopVar = DS->getSingleDecl();
1953  if (LoopVar->isInvalidDecl() || !Range ||
1954      DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) {
1955    LoopVar->setInvalidDecl();
1956    return StmtError();
1957  }
1958
1959  // Build  auto && __range = range-init
1960  SourceLocation RangeLoc = Range->getLocStart();
1961  VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc,
1962                                           Context.getAutoRRefDeductType(),
1963                                           "__range");
1964  if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
1965                            diag::err_for_range_deduction_failure)) {
1966    LoopVar->setInvalidDecl();
1967    return StmtError();
1968  }
1969
1970  // Claim the type doesn't contain auto: we've already done the checking.
1971  DeclGroupPtrTy RangeGroup =
1972      BuildDeclaratorGroup(MutableArrayRef<Decl *>((Decl **)&RangeVar, 1),
1973                           /*TypeMayContainAuto=*/ false);
1974  StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc);
1975  if (RangeDecl.isInvalid()) {
1976    LoopVar->setInvalidDecl();
1977    return StmtError();
1978  }
1979
1980  return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(),
1981                              /*BeginEndDecl=*/nullptr, /*Cond=*/nullptr,
1982                              /*Inc=*/nullptr, DS, RParenLoc, Kind);
1983}
1984
1985/// \brief Create the initialization, compare, and increment steps for
1986/// the range-based for loop expression.
1987/// This function does not handle array-based for loops,
1988/// which are created in Sema::BuildCXXForRangeStmt.
1989///
1990/// \returns a ForRangeStatus indicating success or what kind of error occurred.
1991/// BeginExpr and EndExpr are set and FRS_Success is returned on success;
1992/// CandidateSet and BEF are set and some non-success value is returned on
1993/// failure.
1994static Sema::ForRangeStatus BuildNonArrayForRange(Sema &SemaRef, Scope *S,
1995                                            Expr *BeginRange, Expr *EndRange,
1996                                            QualType RangeType,
1997                                            VarDecl *BeginVar,
1998                                            VarDecl *EndVar,
1999                                            SourceLocation ColonLoc,
2000                                            OverloadCandidateSet *CandidateSet,
2001                                            ExprResult *BeginExpr,
2002                                            ExprResult *EndExpr,
2003                                            Sema::BeginEndFunction *BEF) {
2004  DeclarationNameInfo BeginNameInfo(
2005      &SemaRef.PP.getIdentifierTable().get("begin"), ColonLoc);
2006  DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get("end"),
2007                                  ColonLoc);
2008
2009  LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
2010                                 Sema::LookupMemberName);
2011  LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
2012
2013  if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
2014    // - if _RangeT is a class type, the unqualified-ids begin and end are
2015    //   looked up in the scope of class _RangeT as if by class member access
2016    //   lookup (3.4.5), and if either (or both) finds at least one
2017    //   declaration, begin-expr and end-expr are __range.begin() and
2018    //   __range.end(), respectively;
2019    SemaRef.LookupQualifiedName(BeginMemberLookup, D);
2020    SemaRef.LookupQualifiedName(EndMemberLookup, D);
2021
2022    if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
2023      SourceLocation RangeLoc = BeginVar->getLocation();
2024      *BEF = BeginMemberLookup.empty() ? Sema::BEF_end : Sema::BEF_begin;
2025
2026      SemaRef.Diag(RangeLoc, diag::err_for_range_member_begin_end_mismatch)
2027          << RangeLoc << BeginRange->getType() << *BEF;
2028      return Sema::FRS_DiagnosticIssued;
2029    }
2030  } else {
2031    // - otherwise, begin-expr and end-expr are begin(__range) and
2032    //   end(__range), respectively, where begin and end are looked up with
2033    //   argument-dependent lookup (3.4.2). For the purposes of this name
2034    //   lookup, namespace std is an associated namespace.
2035
2036  }
2037
2038  *BEF = Sema::BEF_begin;
2039  Sema::ForRangeStatus RangeStatus =
2040      SemaRef.BuildForRangeBeginEndCall(S, ColonLoc, ColonLoc, BeginVar,
2041                                        Sema::BEF_begin, BeginNameInfo,
2042                                        BeginMemberLookup, CandidateSet,
2043                                        BeginRange, BeginExpr);
2044
2045  if (RangeStatus != Sema::FRS_Success)
2046    return RangeStatus;
2047  if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
2048                            diag::err_for_range_iter_deduction_failure)) {
2049    NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
2050    return Sema::FRS_DiagnosticIssued;
2051  }
2052
2053  *BEF = Sema::BEF_end;
2054  RangeStatus =
2055      SemaRef.BuildForRangeBeginEndCall(S, ColonLoc, ColonLoc, EndVar,
2056                                        Sema::BEF_end, EndNameInfo,
2057                                        EndMemberLookup, CandidateSet,
2058                                        EndRange, EndExpr);
2059  if (RangeStatus != Sema::FRS_Success)
2060    return RangeStatus;
2061  if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
2062                            diag::err_for_range_iter_deduction_failure)) {
2063    NoteForRangeBeginEndFunction(SemaRef, EndExpr->get(), *BEF);
2064    return Sema::FRS_DiagnosticIssued;
2065  }
2066  return Sema::FRS_Success;
2067}
2068
2069/// Speculatively attempt to dereference an invalid range expression.
2070/// If the attempt fails, this function will return a valid, null StmtResult
2071/// and emit no diagnostics.
2072static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
2073                                                 SourceLocation ForLoc,
2074                                                 Stmt *LoopVarDecl,
2075                                                 SourceLocation ColonLoc,
2076                                                 Expr *Range,
2077                                                 SourceLocation RangeLoc,
2078                                                 SourceLocation RParenLoc) {
2079  // Determine whether we can rebuild the for-range statement with a
2080  // dereferenced range expression.
2081  ExprResult AdjustedRange;
2082  {
2083    Sema::SFINAETrap Trap(SemaRef);
2084
2085    AdjustedRange = SemaRef.BuildUnaryOp(S, RangeLoc, UO_Deref, Range);
2086    if (AdjustedRange.isInvalid())
2087      return StmtResult();
2088
2089    StmtResult SR =
2090      SemaRef.ActOnCXXForRangeStmt(ForLoc, LoopVarDecl, ColonLoc,
2091                                   AdjustedRange.get(), RParenLoc,
2092                                   Sema::BFRK_Check);
2093    if (SR.isInvalid())
2094      return StmtResult();
2095  }
2096
2097  // The attempt to dereference worked well enough that it could produce a valid
2098  // loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
2099  // case there are any other (non-fatal) problems with it.
2100  SemaRef.Diag(RangeLoc, diag::err_for_range_dereference)
2101    << Range->getType() << FixItHint::CreateInsertion(RangeLoc, "*");
2102  return SemaRef.ActOnCXXForRangeStmt(ForLoc, LoopVarDecl, ColonLoc,
2103                                      AdjustedRange.get(), RParenLoc,
2104                                      Sema::BFRK_Rebuild);
2105}
2106
2107namespace {
2108/// RAII object to automatically invalidate a declaration if an error occurs.
2109struct InvalidateOnErrorScope {
2110  InvalidateOnErrorScope(Sema &SemaRef, Decl *D, bool Enabled)
2111      : Trap(SemaRef.Diags), D(D), Enabled(Enabled) {}
2112  ~InvalidateOnErrorScope() {
2113    if (Enabled && Trap.hasErrorOccurred())
2114      D->setInvalidDecl();
2115  }
2116
2117  DiagnosticErrorTrap Trap;
2118  Decl *D;
2119  bool Enabled;
2120};
2121}
2122
2123/// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
2124StmtResult
2125Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc,
2126                           Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond,
2127                           Expr *Inc, Stmt *LoopVarDecl,
2128                           SourceLocation RParenLoc, BuildForRangeKind Kind) {
2129  Scope *S = getCurScope();
2130
2131  DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl);
2132  VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl());
2133  QualType RangeVarType = RangeVar->getType();
2134
2135  DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl);
2136  VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl());
2137
2138  // If we hit any errors, mark the loop variable as invalid if its type
2139  // contains 'auto'.
2140  InvalidateOnErrorScope Invalidate(*this, LoopVar,
2141                                    LoopVar->getType()->isUndeducedType());
2142
2143  StmtResult BeginEndDecl = BeginEnd;
2144  ExprResult NotEqExpr = Cond, IncrExpr = Inc;
2145
2146  if (RangeVarType->isDependentType()) {
2147    // The range is implicitly used as a placeholder when it is dependent.
2148    RangeVar->markUsed(Context);
2149
2150    // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
2151    // them in properly when we instantiate the loop.
2152    if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check)
2153      LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
2154  } else if (!BeginEndDecl.get()) {
2155    SourceLocation RangeLoc = RangeVar->getLocation();
2156
2157    const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
2158
2159    ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2160                                                VK_LValue, ColonLoc);
2161    if (BeginRangeRef.isInvalid())
2162      return StmtError();
2163
2164    ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2165                                              VK_LValue, ColonLoc);
2166    if (EndRangeRef.isInvalid())
2167      return StmtError();
2168
2169    QualType AutoType = Context.getAutoDeductType();
2170    Expr *Range = RangeVar->getInit();
2171    if (!Range)
2172      return StmtError();
2173    QualType RangeType = Range->getType();
2174
2175    if (RequireCompleteType(RangeLoc, RangeType,
2176                            diag::err_for_range_incomplete_type))
2177      return StmtError();
2178
2179    // Build auto __begin = begin-expr, __end = end-expr.
2180    VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2181                                             "__begin");
2182    VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2183                                           "__end");
2184
2185    // Build begin-expr and end-expr and attach to __begin and __end variables.
2186    ExprResult BeginExpr, EndExpr;
2187    if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
2188      // - if _RangeT is an array type, begin-expr and end-expr are __range and
2189      //   __range + __bound, respectively, where __bound is the array bound. If
2190      //   _RangeT is an array of unknown size or an array of incomplete type,
2191      //   the program is ill-formed;
2192
2193      // begin-expr is __range.
2194      BeginExpr = BeginRangeRef;
2195      if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
2196                                diag::err_for_range_iter_deduction_failure)) {
2197        NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2198        return StmtError();
2199      }
2200
2201      // Find the array bound.
2202      ExprResult BoundExpr;
2203      if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT))
2204        BoundExpr = IntegerLiteral::Create(
2205            Context, CAT->getSize(), Context.getPointerDiffType(), RangeLoc);
2206      else if (const VariableArrayType *VAT =
2207               dyn_cast<VariableArrayType>(UnqAT))
2208        BoundExpr = VAT->getSizeExpr();
2209      else {
2210        // Can't be a DependentSizedArrayType or an IncompleteArrayType since
2211        // UnqAT is not incomplete and Range is not type-dependent.
2212        llvm_unreachable("Unexpected array type in for-range");
2213      }
2214
2215      // end-expr is __range + __bound.
2216      EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(),
2217                           BoundExpr.get());
2218      if (EndExpr.isInvalid())
2219        return StmtError();
2220      if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc,
2221                                diag::err_for_range_iter_deduction_failure)) {
2222        NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2223        return StmtError();
2224      }
2225    } else {
2226      OverloadCandidateSet CandidateSet(RangeLoc,
2227                                        OverloadCandidateSet::CSK_Normal);
2228      Sema::BeginEndFunction BEFFailure;
2229      ForRangeStatus RangeStatus =
2230          BuildNonArrayForRange(*this, S, BeginRangeRef.get(),
2231                                EndRangeRef.get(), RangeType,
2232                                BeginVar, EndVar, ColonLoc, &CandidateSet,
2233                                &BeginExpr, &EndExpr, &BEFFailure);
2234
2235      if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
2236          BEFFailure == BEF_begin) {
2237        // If the range is being built from an array parameter, emit a
2238        // a diagnostic that it is being treated as a pointer.
2239        if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Range)) {
2240          if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
2241            QualType ArrayTy = PVD->getOriginalType();
2242            QualType PointerTy = PVD->getType();
2243            if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
2244              Diag(Range->getLocStart(), diag::err_range_on_array_parameter)
2245                << RangeLoc << PVD << ArrayTy << PointerTy;
2246              Diag(PVD->getLocation(), diag::note_declared_at);
2247              return StmtError();
2248            }
2249          }
2250        }
2251
2252        // If building the range failed, try dereferencing the range expression
2253        // unless a diagnostic was issued or the end function is problematic.
2254        StmtResult SR = RebuildForRangeWithDereference(*this, S, ForLoc,
2255                                                       LoopVarDecl, ColonLoc,
2256                                                       Range, RangeLoc,
2257                                                       RParenLoc);
2258        if (SR.isInvalid() || SR.isUsable())
2259          return SR;
2260      }
2261
2262      // Otherwise, emit diagnostics if we haven't already.
2263      if (RangeStatus == FRS_NoViableFunction) {
2264        Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
2265        Diag(Range->getLocStart(), diag::err_for_range_invalid)
2266            << RangeLoc << Range->getType() << BEFFailure;
2267        CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Range);
2268      }
2269      // Return an error if no fix was discovered.
2270      if (RangeStatus != FRS_Success)
2271        return StmtError();
2272    }
2273
2274    assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&
2275           "invalid range expression in for loop");
2276
2277    // C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
2278    QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
2279    if (!Context.hasSameType(BeginType, EndType)) {
2280      Diag(RangeLoc, diag::err_for_range_begin_end_types_differ)
2281        << BeginType << EndType;
2282      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2283      NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2284    }
2285
2286    Decl *BeginEndDecls[] = { BeginVar, EndVar };
2287    // Claim the type doesn't contain auto: we've already done the checking.
2288    DeclGroupPtrTy BeginEndGroup =
2289        BuildDeclaratorGroup(MutableArrayRef<Decl *>(BeginEndDecls, 2),
2290                             /*TypeMayContainAuto=*/ false);
2291    BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc);
2292
2293    const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
2294    ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2295                                           VK_LValue, ColonLoc);
2296    if (BeginRef.isInvalid())
2297      return StmtError();
2298
2299    ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
2300                                         VK_LValue, ColonLoc);
2301    if (EndRef.isInvalid())
2302      return StmtError();
2303
2304    // Build and check __begin != __end expression.
2305    NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
2306                           BeginRef.get(), EndRef.get());
2307    NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get());
2308    NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
2309    if (NotEqExpr.isInvalid()) {
2310      Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2311        << RangeLoc << 0 << BeginRangeRef.get()->getType();
2312      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2313      if (!Context.hasSameType(BeginType, EndType))
2314        NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2315      return StmtError();
2316    }
2317
2318    // Build and check ++__begin expression.
2319    BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2320                                VK_LValue, ColonLoc);
2321    if (BeginRef.isInvalid())
2322      return StmtError();
2323
2324    IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get());
2325    IncrExpr = ActOnFinishFullExpr(IncrExpr.get());
2326    if (IncrExpr.isInvalid()) {
2327      Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2328        << RangeLoc << 2 << BeginRangeRef.get()->getType() ;
2329      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2330      return StmtError();
2331    }
2332
2333    // Build and check *__begin  expression.
2334    BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2335                                VK_LValue, ColonLoc);
2336    if (BeginRef.isInvalid())
2337      return StmtError();
2338
2339    ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get());
2340    if (DerefExpr.isInvalid()) {
2341      Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2342        << RangeLoc << 1 << BeginRangeRef.get()->getType();
2343      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2344      return StmtError();
2345    }
2346
2347    // Attach  *__begin  as initializer for VD. Don't touch it if we're just
2348    // trying to determine whether this would be a valid range.
2349    if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2350      AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false,
2351                           /*TypeMayContainAuto=*/true);
2352      if (LoopVar->isInvalidDecl())
2353        NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2354    }
2355  }
2356
2357  // Don't bother to actually allocate the result if we're just trying to
2358  // determine whether it would be valid.
2359  if (Kind == BFRK_Check)
2360    return StmtResult();
2361
2362  return new (Context) CXXForRangeStmt(
2363      RangeDS, cast_or_null<DeclStmt>(BeginEndDecl.get()), NotEqExpr.get(),
2364      IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, ColonLoc, RParenLoc);
2365}
2366
2367/// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach
2368/// statement.
2369StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) {
2370  if (!S || !B)
2371    return StmtError();
2372  ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(S);
2373
2374  ForStmt->setBody(B);
2375  return S;
2376}
2377
2378// Warn when the loop variable is a const reference that creates a copy.
2379// Suggest using the non-reference type for copies.  If a copy can be prevented
2380// suggest the const reference type that would do so.
2381// For instance, given "for (const &Foo : Range)", suggest
2382// "for (const Foo : Range)" to denote a copy is made for the loop.  If
2383// possible, also suggest "for (const &Bar : Range)" if this type prevents
2384// the copy altogether.
2385static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
2386                                                    const VarDecl *VD,
2387                                                    QualType RangeInitType) {
2388  const Expr *InitExpr = VD->getInit();
2389  if (!InitExpr)
2390    return;
2391
2392  QualType VariableType = VD->getType();
2393
2394  const MaterializeTemporaryExpr *MTE =
2395      dyn_cast<MaterializeTemporaryExpr>(InitExpr);
2396
2397  // No copy made.
2398  if (!MTE)
2399    return;
2400
2401  const Expr *E = MTE->GetTemporaryExpr()->IgnoreImpCasts();
2402
2403  // Searching for either UnaryOperator for dereference of a pointer or
2404  // CXXOperatorCallExpr for handling iterators.
2405  while (!isa<CXXOperatorCallExpr>(E) && !isa<UnaryOperator>(E)) {
2406    if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(E)) {
2407      E = CCE->getArg(0);
2408    } else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(E)) {
2409      const MemberExpr *ME = cast<MemberExpr>(Call->getCallee());
2410      E = ME->getBase();
2411    } else {
2412      const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(E);
2413      E = MTE->GetTemporaryExpr();
2414    }
2415    E = E->IgnoreImpCasts();
2416  }
2417
2418  bool ReturnsReference = false;
2419  if (isa<UnaryOperator>(E)) {
2420    ReturnsReference = true;
2421  } else {
2422    const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(E);
2423    const FunctionDecl *FD = Call->getDirectCallee();
2424    QualType ReturnType = FD->getReturnType();
2425    ReturnsReference = ReturnType->isReferenceType();
2426  }
2427
2428  if (ReturnsReference) {
2429    // Loop variable creates a temporary.  Suggest either to go with
2430    // non-reference loop variable to indiciate a copy is made, or
2431    // the correct time to bind a const reference.
2432    SemaRef.Diag(VD->getLocation(), diag::warn_for_range_const_reference_copy)
2433        << VD << VariableType << E->getType();
2434    QualType NonReferenceType = VariableType.getNonReferenceType();
2435    NonReferenceType.removeLocalConst();
2436    QualType NewReferenceType =
2437        SemaRef.Context.getLValueReferenceType(E->getType().withConst());
2438    SemaRef.Diag(VD->getLocStart(), diag::note_use_type_or_non_reference)
2439        << NonReferenceType << NewReferenceType << VD->getSourceRange();
2440  } else {
2441    // The range always returns a copy, so a temporary is always created.
2442    // Suggest removing the reference from the loop variable.
2443    SemaRef.Diag(VD->getLocation(), diag::warn_for_range_variable_always_copy)
2444        << VD << RangeInitType;
2445    QualType NonReferenceType = VariableType.getNonReferenceType();
2446    NonReferenceType.removeLocalConst();
2447    SemaRef.Diag(VD->getLocStart(), diag::note_use_non_reference_type)
2448        << NonReferenceType << VD->getSourceRange();
2449  }
2450}
2451
2452// Warns when the loop variable can be changed to a reference type to
2453// prevent a copy.  For instance, if given "for (const Foo x : Range)" suggest
2454// "for (const Foo &x : Range)" if this form does not make a copy.
2455static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
2456                                                const VarDecl *VD) {
2457  const Expr *InitExpr = VD->getInit();
2458  if (!InitExpr)
2459    return;
2460
2461  QualType VariableType = VD->getType();
2462
2463  if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(InitExpr)) {
2464    if (!CE->getConstructor()->isCopyConstructor())
2465      return;
2466  } else if (const CastExpr *CE = dyn_cast<CastExpr>(InitExpr)) {
2467    if (CE->getCastKind() != CK_LValueToRValue)
2468      return;
2469  } else {
2470    return;
2471  }
2472
2473  // TODO: Determine a maximum size that a POD type can be before a diagnostic
2474  // should be emitted.  Also, only ignore POD types with trivial copy
2475  // constructors.
2476  if (VariableType.isPODType(SemaRef.Context))
2477    return;
2478
2479  // Suggest changing from a const variable to a const reference variable
2480  // if doing so will prevent a copy.
2481  SemaRef.Diag(VD->getLocation(), diag::warn_for_range_copy)
2482      << VD << VariableType << InitExpr->getType();
2483  SemaRef.Diag(VD->getLocStart(), diag::note_use_reference_type)
2484      << SemaRef.Context.getLValueReferenceType(VariableType)
2485      << VD->getSourceRange();
2486}
2487
2488/// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
2489/// 1) for (const foo &x : foos) where foos only returns a copy.  Suggest
2490///    using "const foo x" to show that a copy is made
2491/// 2) for (const bar &x : foos) where bar is a temporary intialized by bar.
2492///    Suggest either "const bar x" to keep the copying or "const foo& x" to
2493///    prevent the copy.
2494/// 3) for (const foo x : foos) where x is constructed from a reference foo.
2495///    Suggest "const foo &x" to prevent the copy.
2496static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
2497                                           const CXXForRangeStmt *ForStmt) {
2498  if (SemaRef.Diags.isIgnored(diag::warn_for_range_const_reference_copy,
2499                              ForStmt->getLocStart()) &&
2500      SemaRef.Diags.isIgnored(diag::warn_for_range_variable_always_copy,
2501                              ForStmt->getLocStart()) &&
2502      SemaRef.Diags.isIgnored(diag::warn_for_range_copy,
2503                              ForStmt->getLocStart())) {
2504    return;
2505  }
2506
2507  const VarDecl *VD = ForStmt->getLoopVariable();
2508  if (!VD)
2509    return;
2510
2511  QualType VariableType = VD->getType();
2512
2513  if (VariableType->isIncompleteType())
2514    return;
2515
2516  const Expr *InitExpr = VD->getInit();
2517  if (!InitExpr)
2518    return;
2519
2520  if (VariableType->isReferenceType()) {
2521    DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
2522                                            ForStmt->getRangeInit()->getType());
2523  } else if (VariableType.isConstQualified()) {
2524    DiagnoseForRangeConstVariableCopies(SemaRef, VD);
2525  }
2526}
2527
2528/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
2529/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
2530/// body cannot be performed until after the type of the range variable is
2531/// determined.
2532StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
2533  if (!S || !B)
2534    return StmtError();
2535
2536  if (isa<ObjCForCollectionStmt>(S))
2537    return FinishObjCForCollectionStmt(S, B);
2538
2539  CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S);
2540  ForStmt->setBody(B);
2541
2542  DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
2543                        diag::warn_empty_range_based_for_body);
2544
2545  DiagnoseForRangeVariableCopies(*this, ForStmt);
2546
2547  return S;
2548}
2549
2550StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
2551                               SourceLocation LabelLoc,
2552                               LabelDecl *TheDecl) {
2553  getCurFunction()->setHasBranchIntoScope();
2554  TheDecl->markUsed(Context);
2555  return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
2556}
2557
2558StmtResult
2559Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
2560                            Expr *E) {
2561  // Convert operand to void*
2562  if (!E->isTypeDependent()) {
2563    QualType ETy = E->getType();
2564    QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
2565    ExprResult ExprRes = E;
2566    AssignConvertType ConvTy =
2567      CheckSingleAssignmentConstraints(DestTy, ExprRes);
2568    if (ExprRes.isInvalid())
2569      return StmtError();
2570    E = ExprRes.get();
2571    if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
2572      return StmtError();
2573  }
2574
2575  ExprResult ExprRes = ActOnFinishFullExpr(E);
2576  if (ExprRes.isInvalid())
2577    return StmtError();
2578  E = ExprRes.get();
2579
2580  getCurFunction()->setHasIndirectGoto();
2581
2582  return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
2583}
2584
2585static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
2586                                     const Scope &DestScope) {
2587  if (!S.CurrentSEHFinally.empty() &&
2588      DestScope.Contains(*S.CurrentSEHFinally.back())) {
2589    S.Diag(Loc, diag::warn_jump_out_of_seh_finally);
2590  }
2591}
2592
2593StmtResult
2594Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
2595  Scope *S = CurScope->getContinueParent();
2596  if (!S) {
2597    // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
2598    return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
2599  }
2600  CheckJumpOutOfSEHFinally(*this, ContinueLoc, *S);
2601
2602  return new (Context) ContinueStmt(ContinueLoc);
2603}
2604
2605StmtResult
2606Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
2607  Scope *S = CurScope->getBreakParent();
2608  if (!S) {
2609    // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
2610    return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
2611  }
2612  if (S->isOpenMPLoopScope())
2613    return StmtError(Diag(BreakLoc, diag::err_omp_loop_cannot_use_stmt)
2614                     << "break");
2615  CheckJumpOutOfSEHFinally(*this, BreakLoc, *S);
2616
2617  return new (Context) BreakStmt(BreakLoc);
2618}
2619
2620/// \brief Determine whether the given expression is a candidate for
2621/// copy elision in either a return statement or a throw expression.
2622///
2623/// \param ReturnType If we're determining the copy elision candidate for
2624/// a return statement, this is the return type of the function. If we're
2625/// determining the copy elision candidate for a throw expression, this will
2626/// be a NULL type.
2627///
2628/// \param E The expression being returned from the function or block, or
2629/// being thrown.
2630///
2631/// \param AllowFunctionParameter Whether we allow function parameters to
2632/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but
2633/// we re-use this logic to determine whether we should try to move as part of
2634/// a return or throw (which does allow function parameters).
2635///
2636/// \returns The NRVO candidate variable, if the return statement may use the
2637/// NRVO, or NULL if there is no such candidate.
2638VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType,
2639                                       Expr *E,
2640                                       bool AllowFunctionParameter) {
2641  if (!getLangOpts().CPlusPlus)
2642    return nullptr;
2643
2644  // - in a return statement in a function [where] ...
2645  // ... the expression is the name of a non-volatile automatic object ...
2646  DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens());
2647  if (!DR || DR->refersToEnclosingVariableOrCapture())
2648    return nullptr;
2649  VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
2650  if (!VD)
2651    return nullptr;
2652
2653  if (isCopyElisionCandidate(ReturnType, VD, AllowFunctionParameter))
2654    return VD;
2655  return nullptr;
2656}
2657
2658bool Sema::isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
2659                                  bool AllowFunctionParameter) {
2660  QualType VDType = VD->getType();
2661  // - in a return statement in a function with ...
2662  // ... a class return type ...
2663  if (!ReturnType.isNull() && !ReturnType->isDependentType()) {
2664    if (!ReturnType->isRecordType())
2665      return false;
2666    // ... the same cv-unqualified type as the function return type ...
2667    if (!VDType->isDependentType() &&
2668        !Context.hasSameUnqualifiedType(ReturnType, VDType))
2669      return false;
2670  }
2671
2672  // ...object (other than a function or catch-clause parameter)...
2673  if (VD->getKind() != Decl::Var &&
2674      !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar))
2675    return false;
2676  if (VD->isExceptionVariable()) return false;
2677
2678  // ...automatic...
2679  if (!VD->hasLocalStorage()) return false;
2680
2681  // ...non-volatile...
2682  if (VD->getType().isVolatileQualified()) return false;
2683
2684  // __block variables can't be allocated in a way that permits NRVO.
2685  if (VD->hasAttr<BlocksAttr>()) return false;
2686
2687  // Variables with higher required alignment than their type's ABI
2688  // alignment cannot use NRVO.
2689  if (!VD->getType()->isDependentType() && VD->hasAttr<AlignedAttr>() &&
2690      Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType()))
2691    return false;
2692
2693  return true;
2694}
2695
2696/// \brief Perform the initialization of a potentially-movable value, which
2697/// is the result of return value.
2698///
2699/// This routine implements C++0x [class.copy]p33, which attempts to treat
2700/// returned lvalues as rvalues in certain cases (to prefer move construction),
2701/// then falls back to treating them as lvalues if that failed.
2702ExprResult
2703Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
2704                                      const VarDecl *NRVOCandidate,
2705                                      QualType ResultType,
2706                                      Expr *Value,
2707                                      bool AllowNRVO) {
2708  // C++0x [class.copy]p33:
2709  //   When the criteria for elision of a copy operation are met or would
2710  //   be met save for the fact that the source object is a function
2711  //   parameter, and the object to be copied is designated by an lvalue,
2712  //   overload resolution to select the constructor for the copy is first
2713  //   performed as if the object were designated by an rvalue.
2714  ExprResult Res = ExprError();
2715  if (AllowNRVO &&
2716      (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) {
2717    ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack,
2718                              Value->getType(), CK_NoOp, Value, VK_XValue);
2719
2720    Expr *InitExpr = &AsRvalue;
2721    InitializationKind Kind
2722      = InitializationKind::CreateCopy(Value->getLocStart(),
2723                                       Value->getLocStart());
2724    InitializationSequence Seq(*this, Entity, Kind, InitExpr);
2725
2726    //   [...] If overload resolution fails, or if the type of the first
2727    //   parameter of the selected constructor is not an rvalue reference
2728    //   to the object's type (possibly cv-qualified), overload resolution
2729    //   is performed again, considering the object as an lvalue.
2730    if (Seq) {
2731      for (InitializationSequence::step_iterator Step = Seq.step_begin(),
2732           StepEnd = Seq.step_end();
2733           Step != StepEnd; ++Step) {
2734        if (Step->Kind != InitializationSequence::SK_ConstructorInitialization)
2735          continue;
2736
2737        CXXConstructorDecl *Constructor
2738        = cast<CXXConstructorDecl>(Step->Function.Function);
2739
2740        const RValueReferenceType *RRefType
2741          = Constructor->getParamDecl(0)->getType()
2742                                                 ->getAs<RValueReferenceType>();
2743
2744        // If we don't meet the criteria, break out now.
2745        if (!RRefType ||
2746            !Context.hasSameUnqualifiedType(RRefType->getPointeeType(),
2747                            Context.getTypeDeclType(Constructor->getParent())))
2748          break;
2749
2750        // Promote "AsRvalue" to the heap, since we now need this
2751        // expression node to persist.
2752        Value = ImplicitCastExpr::Create(Context, Value->getType(),
2753                                         CK_NoOp, Value, nullptr, VK_XValue);
2754
2755        // Complete type-checking the initialization of the return type
2756        // using the constructor we found.
2757        Res = Seq.Perform(*this, Entity, Kind, Value);
2758      }
2759    }
2760  }
2761
2762  // Either we didn't meet the criteria for treating an lvalue as an rvalue,
2763  // above, or overload resolution failed. Either way, we need to try
2764  // (again) now with the return value expression as written.
2765  if (Res.isInvalid())
2766    Res = PerformCopyInitialization(Entity, SourceLocation(), Value);
2767
2768  return Res;
2769}
2770
2771/// \brief Determine whether the declared return type of the specified function
2772/// contains 'auto'.
2773static bool hasDeducedReturnType(FunctionDecl *FD) {
2774  const FunctionProtoType *FPT =
2775      FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
2776  return FPT->getReturnType()->isUndeducedType();
2777}
2778
2779/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
2780/// for capturing scopes.
2781///
2782StmtResult
2783Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
2784  // If this is the first return we've seen, infer the return type.
2785  // [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
2786  CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
2787  QualType FnRetType = CurCap->ReturnType;
2788  LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(CurCap);
2789
2790  if (CurLambda && hasDeducedReturnType(CurLambda->CallOperator)) {
2791    // In C++1y, the return type may involve 'auto'.
2792    // FIXME: Blocks might have a return type of 'auto' explicitly specified.
2793    FunctionDecl *FD = CurLambda->CallOperator;
2794    if (CurCap->ReturnType.isNull())
2795      CurCap->ReturnType = FD->getReturnType();
2796
2797    AutoType *AT = CurCap->ReturnType->getContainedAutoType();
2798    assert(AT && "lost auto type from lambda return type");
2799    if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
2800      FD->setInvalidDecl();
2801      return StmtError();
2802    }
2803    CurCap->ReturnType = FnRetType = FD->getReturnType();
2804  } else if (CurCap->HasImplicitReturnType) {
2805    // For blocks/lambdas with implicit return types, we check each return
2806    // statement individually, and deduce the common return type when the block
2807    // or lambda is completed.
2808    // FIXME: Fold this into the 'auto' codepath above.
2809    if (RetValExp && !isa<InitListExpr>(RetValExp)) {
2810      ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
2811      if (Result.isInvalid())
2812        return StmtError();
2813      RetValExp = Result.get();
2814
2815      // DR1048: even prior to C++14, we should use the 'auto' deduction rules
2816      // when deducing a return type for a lambda-expression (or by extension
2817      // for a block). These rules differ from the stated C++11 rules only in
2818      // that they remove top-level cv-qualifiers.
2819      if (!CurContext->isDependentContext())
2820        FnRetType = RetValExp->getType().getUnqualifiedType();
2821      else
2822        FnRetType = CurCap->ReturnType = Context.DependentTy;
2823    } else {
2824      if (RetValExp) {
2825        // C++11 [expr.lambda.prim]p4 bans inferring the result from an
2826        // initializer list, because it is not an expression (even
2827        // though we represent it as one). We still deduce 'void'.
2828        Diag(ReturnLoc, diag::err_lambda_return_init_list)
2829          << RetValExp->getSourceRange();
2830      }
2831
2832      FnRetType = Context.VoidTy;
2833    }
2834
2835    // Although we'll properly infer the type of the block once it's completed,
2836    // make sure we provide a return type now for better error recovery.
2837    if (CurCap->ReturnType.isNull())
2838      CurCap->ReturnType = FnRetType;
2839  }
2840  assert(!FnRetType.isNull());
2841
2842  if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) {
2843    if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) {
2844      Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
2845      return StmtError();
2846    }
2847  } else if (CapturedRegionScopeInfo *CurRegion =
2848                 dyn_cast<CapturedRegionScopeInfo>(CurCap)) {
2849    Diag(ReturnLoc, diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
2850    return StmtError();
2851  } else {
2852    assert(CurLambda && "unknown kind of captured scope");
2853    if (CurLambda->CallOperator->getType()->getAs<FunctionType>()
2854            ->getNoReturnAttr()) {
2855      Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr);
2856      return StmtError();
2857    }
2858  }
2859
2860  // Otherwise, verify that this result type matches the previous one.  We are
2861  // pickier with blocks than for normal functions because we don't have GCC
2862  // compatibility to worry about here.
2863  const VarDecl *NRVOCandidate = nullptr;
2864  if (FnRetType->isDependentType()) {
2865    // Delay processing for now.  TODO: there are lots of dependent
2866    // types we can conclusively prove aren't void.
2867  } else if (FnRetType->isVoidType()) {
2868    if (RetValExp && !isa<InitListExpr>(RetValExp) &&
2869        !(getLangOpts().CPlusPlus &&
2870          (RetValExp->isTypeDependent() ||
2871           RetValExp->getType()->isVoidType()))) {
2872      if (!getLangOpts().CPlusPlus &&
2873          RetValExp->getType()->isVoidType())
2874        Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
2875      else {
2876        Diag(ReturnLoc, diag::err_return_block_has_expr);
2877        RetValExp = nullptr;
2878      }
2879    }
2880  } else if (!RetValExp) {
2881    return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
2882  } else if (!RetValExp->isTypeDependent()) {
2883    // we have a non-void block with an expression, continue checking
2884
2885    // C99 6.8.6.4p3(136): The return statement is not an assignment. The
2886    // overlap restriction of subclause 6.5.16.1 does not apply to the case of
2887    // function return.
2888
2889    // In C++ the return statement is handled via a copy initialization.
2890    // the C version of which boils down to CheckSingleAssignmentConstraints.
2891    NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
2892    InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
2893                                                                   FnRetType,
2894                                                      NRVOCandidate != nullptr);
2895    ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
2896                                                     FnRetType, RetValExp);
2897    if (Res.isInvalid()) {
2898      // FIXME: Cleanup temporaries here, anyway?
2899      return StmtError();
2900    }
2901    RetValExp = Res.get();
2902    CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc);
2903  } else {
2904    NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
2905  }
2906
2907  if (RetValExp) {
2908    ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
2909    if (ER.isInvalid())
2910      return StmtError();
2911    RetValExp = ER.get();
2912  }
2913  ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp,
2914                                                NRVOCandidate);
2915
2916  // If we need to check for the named return value optimization,
2917  // or if we need to infer the return type,
2918  // save the return statement in our scope for later processing.
2919  if (CurCap->HasImplicitReturnType || NRVOCandidate)
2920    FunctionScopes.back()->Returns.push_back(Result);
2921
2922  return Result;
2923}
2924
2925namespace {
2926/// \brief Marks all typedefs in all local classes in a type referenced.
2927///
2928/// In a function like
2929/// auto f() {
2930///   struct S { typedef int a; };
2931///   return S();
2932/// }
2933///
2934/// the local type escapes and could be referenced in some TUs but not in
2935/// others. Pretend that all local typedefs are always referenced, to not warn
2936/// on this. This isn't necessary if f has internal linkage, or the typedef
2937/// is private.
2938class LocalTypedefNameReferencer
2939    : public RecursiveASTVisitor<LocalTypedefNameReferencer> {
2940public:
2941  LocalTypedefNameReferencer(Sema &S) : S(S) {}
2942  bool VisitRecordType(const RecordType *RT);
2943private:
2944  Sema &S;
2945};
2946bool LocalTypedefNameReferencer::VisitRecordType(const RecordType *RT) {
2947  auto *R = dyn_cast<CXXRecordDecl>(RT->getDecl());
2948  if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
2949      R->isDependentType())
2950    return true;
2951  for (auto *TmpD : R->decls())
2952    if (auto *T = dyn_cast<TypedefNameDecl>(TmpD))
2953      if (T->getAccess() != AS_private || R->hasFriends())
2954        S.MarkAnyDeclReferenced(T->getLocation(), T, /*OdrUse=*/false);
2955  return true;
2956}
2957}
2958
2959TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
2960  TypeLoc TL = FD->getTypeSourceInfo()->getTypeLoc().IgnoreParens();
2961  while (auto ATL = TL.getAs<AttributedTypeLoc>())
2962    TL = ATL.getModifiedLoc().IgnoreParens();
2963  return TL.castAs<FunctionProtoTypeLoc>().getReturnLoc();
2964}
2965
2966/// Deduce the return type for a function from a returned expression, per
2967/// C++1y [dcl.spec.auto]p6.
2968bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
2969                                            SourceLocation ReturnLoc,
2970                                            Expr *&RetExpr,
2971                                            AutoType *AT) {
2972  TypeLoc OrigResultType = getReturnTypeLoc(FD);
2973  QualType Deduced;
2974
2975  if (RetExpr && isa<InitListExpr>(RetExpr)) {
2976    //  If the deduction is for a return statement and the initializer is
2977    //  a braced-init-list, the program is ill-formed.
2978    Diag(RetExpr->getExprLoc(),
2979         getCurLambda() ? diag::err_lambda_return_init_list
2980                        : diag::err_auto_fn_return_init_list)
2981        << RetExpr->getSourceRange();
2982    return true;
2983  }
2984
2985  if (FD->isDependentContext()) {
2986    // C++1y [dcl.spec.auto]p12:
2987    //   Return type deduction [...] occurs when the definition is
2988    //   instantiated even if the function body contains a return
2989    //   statement with a non-type-dependent operand.
2990    assert(AT->isDeduced() && "should have deduced to dependent type");
2991    return false;
2992  } else if (RetExpr) {
2993    //  If the deduction is for a return statement and the initializer is
2994    //  a braced-init-list, the program is ill-formed.
2995    if (isa<InitListExpr>(RetExpr)) {
2996      Diag(RetExpr->getExprLoc(), diag::err_auto_fn_return_init_list);
2997      return true;
2998    }
2999
3000    //  Otherwise, [...] deduce a value for U using the rules of template
3001    //  argument deduction.
3002    DeduceAutoResult DAR = DeduceAutoType(OrigResultType, RetExpr, Deduced);
3003
3004    if (DAR == DAR_Failed && !FD->isInvalidDecl())
3005      Diag(RetExpr->getExprLoc(), diag::err_auto_fn_deduction_failure)
3006        << OrigResultType.getType() << RetExpr->getType();
3007
3008    if (DAR != DAR_Succeeded)
3009      return true;
3010
3011    // If a local type is part of the returned type, mark its fields as
3012    // referenced.
3013    LocalTypedefNameReferencer Referencer(*this);
3014    Referencer.TraverseType(RetExpr->getType());
3015  } else {
3016    //  In the case of a return with no operand, the initializer is considered
3017    //  to be void().
3018    //
3019    // Deduction here can only succeed if the return type is exactly 'cv auto'
3020    // or 'decltype(auto)', so just check for that case directly.
3021    if (!OrigResultType.getType()->getAs<AutoType>()) {
3022      Diag(ReturnLoc, diag::err_auto_fn_return_void_but_not_auto)
3023        << OrigResultType.getType();
3024      return true;
3025    }
3026    // We always deduce U = void in this case.
3027    Deduced = SubstAutoType(OrigResultType.getType(), Context.VoidTy);
3028    if (Deduced.isNull())
3029      return true;
3030  }
3031
3032  //  If a function with a declared return type that contains a placeholder type
3033  //  has multiple return statements, the return type is deduced for each return
3034  //  statement. [...] if the type deduced is not the same in each deduction,
3035  //  the program is ill-formed.
3036  if (AT->isDeduced() && !FD->isInvalidDecl()) {
3037    AutoType *NewAT = Deduced->getContainedAutoType();
3038    if (!FD->isDependentContext() &&
3039        !Context.hasSameType(AT->getDeducedType(), NewAT->getDeducedType())) {
3040      const LambdaScopeInfo *LambdaSI = getCurLambda();
3041      if (LambdaSI && LambdaSI->HasImplicitReturnType) {
3042        Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
3043          << NewAT->getDeducedType() << AT->getDeducedType()
3044          << true /*IsLambda*/;
3045      } else {
3046        Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
3047          << (AT->isDecltypeAuto() ? 1 : 0)
3048          << NewAT->getDeducedType() << AT->getDeducedType();
3049      }
3050      return true;
3051    }
3052  } else if (!FD->isInvalidDecl()) {
3053    // Update all declarations of the function to have the deduced return type.
3054    Context.adjustDeducedFunctionResultType(FD, Deduced);
3055  }
3056
3057  return false;
3058}
3059
3060StmtResult
3061Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3062                      Scope *CurScope) {
3063  StmtResult R = BuildReturnStmt(ReturnLoc, RetValExp);
3064  if (R.isInvalid()) {
3065    return R;
3066  }
3067
3068  if (VarDecl *VD =
3069      const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
3070    CurScope->addNRVOCandidate(VD);
3071  } else {
3072    CurScope->setNoNRVO();
3073  }
3074
3075  CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());
3076
3077  return R;
3078}
3079
3080StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
3081  // Check for unexpanded parameter packs.
3082  if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
3083    return StmtError();
3084
3085  if (isa<CapturingScopeInfo>(getCurFunction()))
3086    return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp);
3087
3088  QualType FnRetType;
3089  QualType RelatedRetType;
3090  const AttrVec *Attrs = nullptr;
3091  bool isObjCMethod = false;
3092
3093  if (const FunctionDecl *FD = getCurFunctionDecl()) {
3094    FnRetType = FD->getReturnType();
3095    if (FD->hasAttrs())
3096      Attrs = &FD->getAttrs();
3097    if (FD->isNoReturn())
3098      Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
3099        << FD->getDeclName();
3100  } else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
3101    FnRetType = MD->getReturnType();
3102    isObjCMethod = true;
3103    if (MD->hasAttrs())
3104      Attrs = &MD->getAttrs();
3105    if (MD->hasRelatedResultType() && MD->getClassInterface()) {
3106      // In the implementation of a method with a related return type, the
3107      // type used to type-check the validity of return statements within the
3108      // method body is a pointer to the type of the class being implemented.
3109      RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface());
3110      RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType);
3111    }
3112  } else // If we don't have a function/method context, bail.
3113    return StmtError();
3114
3115  // FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
3116  // deduction.
3117  if (getLangOpts().CPlusPlus14) {
3118    if (AutoType *AT = FnRetType->getContainedAutoType()) {
3119      FunctionDecl *FD = cast<FunctionDecl>(CurContext);
3120      if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
3121        FD->setInvalidDecl();
3122        return StmtError();
3123      } else {
3124        FnRetType = FD->getReturnType();
3125      }
3126    }
3127  }
3128
3129  bool HasDependentReturnType = FnRetType->isDependentType();
3130
3131  ReturnStmt *Result = nullptr;
3132  if (FnRetType->isVoidType()) {
3133    if (RetValExp) {
3134      if (isa<InitListExpr>(RetValExp)) {
3135        // We simply never allow init lists as the return value of void
3136        // functions. This is compatible because this was never allowed before,
3137        // so there's no legacy code to deal with.
3138        NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3139        int FunctionKind = 0;
3140        if (isa<ObjCMethodDecl>(CurDecl))
3141          FunctionKind = 1;
3142        else if (isa<CXXConstructorDecl>(CurDecl))
3143          FunctionKind = 2;
3144        else if (isa<CXXDestructorDecl>(CurDecl))
3145          FunctionKind = 3;
3146
3147        Diag(ReturnLoc, diag::err_return_init_list)
3148          << CurDecl->getDeclName() << FunctionKind
3149          << RetValExp->getSourceRange();
3150
3151        // Drop the expression.
3152        RetValExp = nullptr;
3153      } else if (!RetValExp->isTypeDependent()) {
3154        // C99 6.8.6.4p1 (ext_ since GCC warns)
3155        unsigned D = diag::ext_return_has_expr;
3156        if (RetValExp->getType()->isVoidType()) {
3157          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3158          if (isa<CXXConstructorDecl>(CurDecl) ||
3159              isa<CXXDestructorDecl>(CurDecl))
3160            D = diag::err_ctor_dtor_returns_void;
3161          else
3162            D = diag::ext_return_has_void_expr;
3163        }
3164        else {
3165          ExprResult Result = RetValExp;
3166          Result = IgnoredValueConversions(Result.get());
3167          if (Result.isInvalid())
3168            return StmtError();
3169          RetValExp = Result.get();
3170          RetValExp = ImpCastExprToType(RetValExp,
3171                                        Context.VoidTy, CK_ToVoid).get();
3172        }
3173        // return of void in constructor/destructor is illegal in C++.
3174        if (D == diag::err_ctor_dtor_returns_void) {
3175          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3176          Diag(ReturnLoc, D)
3177            << CurDecl->getDeclName() << isa<CXXDestructorDecl>(CurDecl)
3178            << RetValExp->getSourceRange();
3179        }
3180        // return (some void expression); is legal in C++.
3181        else if (D != diag::ext_return_has_void_expr ||
3182            !getLangOpts().CPlusPlus) {
3183          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3184
3185          int FunctionKind = 0;
3186          if (isa<ObjCMethodDecl>(CurDecl))
3187            FunctionKind = 1;
3188          else if (isa<CXXConstructorDecl>(CurDecl))
3189            FunctionKind = 2;
3190          else if (isa<CXXDestructorDecl>(CurDecl))
3191            FunctionKind = 3;
3192
3193          Diag(ReturnLoc, D)
3194            << CurDecl->getDeclName() << FunctionKind
3195            << RetValExp->getSourceRange();
3196        }
3197      }
3198
3199      if (RetValExp) {
3200        ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3201        if (ER.isInvalid())
3202          return StmtError();
3203        RetValExp = ER.get();
3204      }
3205    }
3206
3207    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
3208  } else if (!RetValExp && !HasDependentReturnType) {
3209    FunctionDecl *FD = getCurFunctionDecl();
3210
3211    unsigned DiagID;
3212    if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
3213      // C++11 [stmt.return]p2
3214      DiagID = diag::err_constexpr_return_missing_expr;
3215      FD->setInvalidDecl();
3216    } else if (getLangOpts().C99) {
3217      // C99 6.8.6.4p1 (ext_ since GCC warns)
3218      DiagID = diag::ext_return_missing_expr;
3219    } else {
3220      // C90 6.6.6.4p4
3221      DiagID = diag::warn_return_missing_expr;
3222    }
3223
3224    if (FD)
3225      Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
3226    else
3227      Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
3228
3229    Result = new (Context) ReturnStmt(ReturnLoc);
3230  } else {
3231    assert(RetValExp || HasDependentReturnType);
3232    const VarDecl *NRVOCandidate = nullptr;
3233
3234    QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
3235
3236    // C99 6.8.6.4p3(136): The return statement is not an assignment. The
3237    // overlap restriction of subclause 6.5.16.1 does not apply to the case of
3238    // function return.
3239
3240    // In C++ the return statement is handled via a copy initialization,
3241    // the C version of which boils down to CheckSingleAssignmentConstraints.
3242    if (RetValExp)
3243      NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
3244    if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
3245      // we have a non-void function with an expression, continue checking
3246      InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
3247                                                                     RetType,
3248                                                      NRVOCandidate != nullptr);
3249      ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
3250                                                       RetType, RetValExp);
3251      if (Res.isInvalid()) {
3252        // FIXME: Clean up temporaries here anyway?
3253        return StmtError();
3254      }
3255      RetValExp = Res.getAs<Expr>();
3256
3257      // If we have a related result type, we need to implicitly
3258      // convert back to the formal result type.  We can't pretend to
3259      // initialize the result again --- we might end double-retaining
3260      // --- so instead we initialize a notional temporary.
3261      if (!RelatedRetType.isNull()) {
3262        Entity = InitializedEntity::InitializeRelatedResult(getCurMethodDecl(),
3263                                                            FnRetType);
3264        Res = PerformCopyInitialization(Entity, ReturnLoc, RetValExp);
3265        if (Res.isInvalid()) {
3266          // FIXME: Clean up temporaries here anyway?
3267          return StmtError();
3268        }
3269        RetValExp = Res.getAs<Expr>();
3270      }
3271
3272      CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc, isObjCMethod, Attrs,
3273                         getCurFunctionDecl());
3274    }
3275
3276    if (RetValExp) {
3277      ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3278      if (ER.isInvalid())
3279        return StmtError();
3280      RetValExp = ER.get();
3281    }
3282    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
3283  }
3284
3285  // If we need to check for the named return value optimization, save the
3286  // return statement in our scope for later processing.
3287  if (Result->getNRVOCandidate())
3288    FunctionScopes.back()->Returns.push_back(Result);
3289
3290  return Result;
3291}
3292
3293StmtResult
3294Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
3295                           SourceLocation RParen, Decl *Parm,
3296                           Stmt *Body) {
3297  VarDecl *Var = cast_or_null<VarDecl>(Parm);
3298  if (Var && Var->isInvalidDecl())
3299    return StmtError();
3300
3301  return new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body);
3302}
3303
3304StmtResult
3305Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
3306  return new (Context) ObjCAtFinallyStmt(AtLoc, Body);
3307}
3308
3309StmtResult
3310Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
3311                         MultiStmtArg CatchStmts, Stmt *Finally) {
3312  if (!getLangOpts().ObjCExceptions)
3313    Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";
3314
3315  getCurFunction()->setHasBranchProtectedScope();
3316  unsigned NumCatchStmts = CatchStmts.size();
3317  return ObjCAtTryStmt::Create(Context, AtLoc, Try, CatchStmts.data(),
3318                               NumCatchStmts, Finally);
3319}
3320
3321StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) {
3322  if (Throw) {
3323    ExprResult Result = DefaultLvalueConversion(Throw);
3324    if (Result.isInvalid())
3325      return StmtError();
3326
3327    Result = ActOnFinishFullExpr(Result.get());
3328    if (Result.isInvalid())
3329      return StmtError();
3330    Throw = Result.get();
3331
3332    QualType ThrowType = Throw->getType();
3333    // Make sure the expression type is an ObjC pointer or "void *".
3334    if (!ThrowType->isDependentType() &&
3335        !ThrowType->isObjCObjectPointerType()) {
3336      const PointerType *PT = ThrowType->getAs<PointerType>();
3337      if (!PT || !PT->getPointeeType()->isVoidType())
3338        return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object)
3339                         << Throw->getType() << Throw->getSourceRange());
3340    }
3341  }
3342
3343  return new (Context) ObjCAtThrowStmt(AtLoc, Throw);
3344}
3345
3346StmtResult
3347Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
3348                           Scope *CurScope) {
3349  if (!getLangOpts().ObjCExceptions)
3350    Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw";
3351
3352  if (!Throw) {
3353    // @throw without an expression designates a rethrow (which must occur
3354    // in the context of an @catch clause).
3355    Scope *AtCatchParent = CurScope;
3356    while (AtCatchParent && !AtCatchParent->isAtCatchScope())
3357      AtCatchParent = AtCatchParent->getParent();
3358    if (!AtCatchParent)
3359      return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch));
3360  }
3361  return BuildObjCAtThrowStmt(AtLoc, Throw);
3362}
3363
3364ExprResult
3365Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
3366  ExprResult result = DefaultLvalueConversion(operand);
3367  if (result.isInvalid())
3368    return ExprError();
3369  operand = result.get();
3370
3371  // Make sure the expression type is an ObjC pointer or "void *".
3372  QualType type = operand->getType();
3373  if (!type->isDependentType() &&
3374      !type->isObjCObjectPointerType()) {
3375    const PointerType *pointerType = type->getAs<PointerType>();
3376    if (!pointerType || !pointerType->getPointeeType()->isVoidType()) {
3377      if (getLangOpts().CPlusPlus) {
3378        if (RequireCompleteType(atLoc, type,
3379                                diag::err_incomplete_receiver_type))
3380          return Diag(atLoc, diag::error_objc_synchronized_expects_object)
3381                   << type << operand->getSourceRange();
3382
3383        ExprResult result = PerformContextuallyConvertToObjCPointer(operand);
3384        if (!result.isUsable())
3385          return Diag(atLoc, diag::error_objc_synchronized_expects_object)
3386                   << type << operand->getSourceRange();
3387
3388        operand = result.get();
3389      } else {
3390          return Diag(atLoc, diag::error_objc_synchronized_expects_object)
3391                   << type << operand->getSourceRange();
3392      }
3393    }
3394  }
3395
3396  // The operand to @synchronized is a full-expression.
3397  return ActOnFinishFullExpr(operand);
3398}
3399
3400StmtResult
3401Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
3402                                  Stmt *SyncBody) {
3403  // We can't jump into or indirect-jump out of a @synchronized block.
3404  getCurFunction()->setHasBranchProtectedScope();
3405  return new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody);
3406}
3407
3408/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
3409/// and creates a proper catch handler from them.
3410StmtResult
3411Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
3412                         Stmt *HandlerBlock) {
3413  // There's nothing to test that ActOnExceptionDecl didn't already test.
3414  return new (Context)
3415      CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(ExDecl), HandlerBlock);
3416}
3417
3418StmtResult
3419Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) {
3420  getCurFunction()->setHasBranchProtectedScope();
3421  return new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body);
3422}
3423
3424namespace {
3425class CatchHandlerType {
3426  QualType QT;
3427  unsigned IsPointer : 1;
3428
3429  // This is a special constructor to be used only with DenseMapInfo's
3430  // getEmptyKey() and getTombstoneKey() functions.
3431  friend struct llvm::DenseMapInfo<CatchHandlerType>;
3432  enum Unique { ForDenseMap };
3433  CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}
3434
3435public:
3436  /// Used when creating a CatchHandlerType from a handler type; will determine
3437  /// whether the type is a pointer or reference and will strip off the top
3438  /// level pointer and cv-qualifiers.
3439  CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
3440    if (QT->isPointerType())
3441      IsPointer = true;
3442
3443    if (IsPointer || QT->isReferenceType())
3444      QT = QT->getPointeeType();
3445    QT = QT.getUnqualifiedType();
3446  }
3447
3448  /// Used when creating a CatchHandlerType from a base class type; pretends the
3449  /// type passed in had the pointer qualifier, does not need to get an
3450  /// unqualified type.
3451  CatchHandlerType(QualType QT, bool IsPointer)
3452      : QT(QT), IsPointer(IsPointer) {}
3453
3454  QualType underlying() const { return QT; }
3455  bool isPointer() const { return IsPointer; }
3456
3457  friend bool operator==(const CatchHandlerType &LHS,
3458                         const CatchHandlerType &RHS) {
3459    // If the pointer qualification does not match, we can return early.
3460    if (LHS.IsPointer != RHS.IsPointer)
3461      return false;
3462    // Otherwise, check the underlying type without cv-qualifiers.
3463    return LHS.QT == RHS.QT;
3464  }
3465};
3466} // namespace
3467
3468namespace llvm {
3469template <> struct DenseMapInfo<CatchHandlerType> {
3470  static CatchHandlerType getEmptyKey() {
3471    return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
3472                       CatchHandlerType::ForDenseMap);
3473  }
3474
3475  static CatchHandlerType getTombstoneKey() {
3476    return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
3477                       CatchHandlerType::ForDenseMap);
3478  }
3479
3480  static unsigned getHashValue(const CatchHandlerType &Base) {
3481    return DenseMapInfo<QualType>::getHashValue(Base.underlying());
3482  }
3483
3484  static bool isEqual(const CatchHandlerType &LHS,
3485                      const CatchHandlerType &RHS) {
3486    return LHS == RHS;
3487  }
3488};
3489
3490// It's OK to treat CatchHandlerType as a POD type.
3491template <> struct isPodLike<CatchHandlerType> {
3492  static const bool value = true;
3493};
3494}
3495
3496namespace {
3497class CatchTypePublicBases {
3498  ASTContext &Ctx;
3499  const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &TypesToCheck;
3500  const bool CheckAgainstPointer;
3501
3502  CXXCatchStmt *FoundHandler;
3503  CanQualType FoundHandlerType;
3504
3505public:
3506  CatchTypePublicBases(
3507      ASTContext &Ctx,
3508      const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &T, bool C)
3509      : Ctx(Ctx), TypesToCheck(T), CheckAgainstPointer(C),
3510        FoundHandler(nullptr) {}
3511
3512  CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
3513  CanQualType getFoundHandlerType() const { return FoundHandlerType; }
3514
3515  static bool FindPublicBasesOfType(const CXXBaseSpecifier *S, CXXBasePath &,
3516                                    void *User) {
3517    auto &PBOT = *reinterpret_cast<CatchTypePublicBases *>(User);
3518    if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
3519      CatchHandlerType Check(S->getType(), PBOT.CheckAgainstPointer);
3520      auto M = PBOT.TypesToCheck;
3521      auto I = M.find(Check);
3522      if (I != M.end()) {
3523        PBOT.FoundHandler = I->second;
3524        PBOT.FoundHandlerType = PBOT.Ctx.getCanonicalType(S->getType());
3525        return true;
3526      }
3527    }
3528    return false;
3529  }
3530};
3531}
3532
3533/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
3534/// handlers and creates a try statement from them.
3535StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
3536                                  ArrayRef<Stmt *> Handlers) {
3537  // Don't report an error if 'try' is used in system headers.
3538  if (!getLangOpts().CXXExceptions &&
3539      !getSourceManager().isInSystemHeader(TryLoc))
3540    Diag(TryLoc, diag::err_exceptions_disabled) << "try";
3541
3542  if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
3543    Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
3544
3545  sema::FunctionScopeInfo *FSI = getCurFunction();
3546
3547  // C++ try is incompatible with SEH __try.
3548  if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
3549    Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
3550    Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
3551  }
3552
3553  const unsigned NumHandlers = Handlers.size();
3554  assert(!Handlers.empty() &&
3555         "The parser shouldn't call this if there are no handlers.");
3556
3557  llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
3558  for (unsigned i = 0; i < NumHandlers; ++i) {
3559    CXXCatchStmt *H = cast<CXXCatchStmt>(Handlers[i]);
3560
3561    // Diagnose when the handler is a catch-all handler, but it isn't the last
3562    // handler for the try block. [except.handle]p5. Also, skip exception
3563    // declarations that are invalid, since we can't usefully report on them.
3564    if (!H->getExceptionDecl()) {
3565      if (i < NumHandlers - 1)
3566        return StmtError(Diag(H->getLocStart(), diag::err_early_catch_all));
3567      continue;
3568    } else if (H->getExceptionDecl()->isInvalidDecl())
3569      continue;
3570
3571    // Walk the type hierarchy to diagnose when this type has already been
3572    // handled (duplication), or cannot be handled (derivation inversion). We
3573    // ignore top-level cv-qualifiers, per [except.handle]p3
3574    CatchHandlerType HandlerCHT =
3575        (QualType)Context.getCanonicalType(H->getCaughtType());
3576
3577    // We can ignore whether the type is a reference or a pointer; we need the
3578    // underlying declaration type in order to get at the underlying record
3579    // decl, if there is one.
3580    QualType Underlying = HandlerCHT.underlying();
3581    if (auto *RD = Underlying->getAsCXXRecordDecl()) {
3582      if (!RD->hasDefinition())
3583        continue;
3584      // Check that none of the public, unambiguous base classes are in the
3585      // map ([except.handle]p1). Give the base classes the same pointer
3586      // qualification as the original type we are basing off of. This allows
3587      // comparison against the handler type using the same top-level pointer
3588      // as the original type.
3589      CXXBasePaths Paths;
3590      Paths.setOrigin(RD);
3591      CatchTypePublicBases CTPB(Context, HandledTypes, HandlerCHT.isPointer());
3592      if (RD->lookupInBases(CatchTypePublicBases::FindPublicBasesOfType, &CTPB,
3593                            Paths)) {
3594        const CXXCatchStmt *Problem = CTPB.getFoundHandler();
3595        if (!Paths.isAmbiguous(CTPB.getFoundHandlerType())) {
3596          Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
3597               diag::warn_exception_caught_by_earlier_handler)
3598              << H->getCaughtType();
3599          Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
3600                diag::note_previous_exception_handler)
3601              << Problem->getCaughtType();
3602        }
3603      }
3604    }
3605
3606    // Add the type the list of ones we have handled; diagnose if we've already
3607    // handled it.
3608    auto R = HandledTypes.insert(std::make_pair(H->getCaughtType(), H));
3609    if (!R.second) {
3610      const CXXCatchStmt *Problem = R.first->second;
3611      Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
3612           diag::warn_exception_caught_by_earlier_handler)
3613          << H->getCaughtType();
3614      Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
3615           diag::note_previous_exception_handler)
3616          << Problem->getCaughtType();
3617    }
3618  }
3619
3620  FSI->setHasCXXTry(TryLoc);
3621
3622  return CXXTryStmt::Create(Context, TryLoc, TryBlock, Handlers);
3623}
3624
3625StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
3626                                  Stmt *TryBlock, Stmt *Handler) {
3627  assert(TryBlock && Handler);
3628
3629  sema::FunctionScopeInfo *FSI = getCurFunction();
3630
3631  // SEH __try is incompatible with C++ try. Borland appears to support this,
3632  // however.
3633  if (!getLangOpts().Borland) {
3634    if (FSI->FirstCXXTryLoc.isValid()) {
3635      Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
3636      Diag(FSI->FirstCXXTryLoc, diag::note_conflicting_try_here) << "'try'";
3637    }
3638  }
3639
3640  FSI->setHasSEHTry(TryLoc);
3641
3642  // Reject __try in Obj-C methods, blocks, and captured decls, since we don't
3643  // track if they use SEH.
3644  DeclContext *DC = CurContext;
3645  while (DC && !DC->isFunctionOrMethod())
3646    DC = DC->getParent();
3647  FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(DC);
3648  if (FD)
3649    FD->setUsesSEHTry(true);
3650  else
3651    Diag(TryLoc, diag::err_seh_try_outside_functions);
3652
3653  // Reject __try on unsupported targets.
3654  if (!Context.getTargetInfo().isSEHTrySupported())
3655    Diag(TryLoc, diag::err_seh_try_unsupported);
3656
3657  return SEHTryStmt::Create(Context, IsCXXTry, TryLoc, TryBlock, Handler);
3658}
3659
3660StmtResult
3661Sema::ActOnSEHExceptBlock(SourceLocation Loc,
3662                          Expr *FilterExpr,
3663                          Stmt *Block) {
3664  assert(FilterExpr && Block);
3665
3666  if(!FilterExpr->getType()->isIntegerType()) {
3667    return StmtError(Diag(FilterExpr->getExprLoc(),
3668                     diag::err_filter_expression_integral)
3669                     << FilterExpr->getType());
3670  }
3671
3672  return SEHExceptStmt::Create(Context,Loc,FilterExpr,Block);
3673}
3674
3675void Sema::ActOnStartSEHFinallyBlock() {
3676  CurrentSEHFinally.push_back(CurScope);
3677}
3678
3679void Sema::ActOnAbortSEHFinallyBlock() {
3680  CurrentSEHFinally.pop_back();
3681}
3682
3683StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
3684  assert(Block);
3685  CurrentSEHFinally.pop_back();
3686  return SEHFinallyStmt::Create(Context, Loc, Block);
3687}
3688
3689StmtResult
3690Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
3691  Scope *SEHTryParent = CurScope;
3692  while (SEHTryParent && !SEHTryParent->isSEHTryScope())
3693    SEHTryParent = SEHTryParent->getParent();
3694  if (!SEHTryParent)
3695    return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
3696  CheckJumpOutOfSEHFinally(*this, Loc, *SEHTryParent);
3697
3698  return new (Context) SEHLeaveStmt(Loc);
3699}
3700
3701StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
3702                                            bool IsIfExists,
3703                                            NestedNameSpecifierLoc QualifierLoc,
3704                                            DeclarationNameInfo NameInfo,
3705                                            Stmt *Nested)
3706{
3707  return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
3708                                             QualifierLoc, NameInfo,
3709                                             cast<CompoundStmt>(Nested));
3710}
3711
3712
3713StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
3714                                            bool IsIfExists,
3715                                            CXXScopeSpec &SS,
3716                                            UnqualifiedId &Name,
3717                                            Stmt *Nested) {
3718  return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
3719                                    SS.getWithLocInContext(Context),
3720                                    GetNameFromUnqualifiedId(Name),
3721                                    Nested);
3722}
3723
3724RecordDecl*
3725Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
3726                                   unsigned NumParams) {
3727  DeclContext *DC = CurContext;
3728  while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
3729    DC = DC->getParent();
3730
3731  RecordDecl *RD = nullptr;
3732  if (getLangOpts().CPlusPlus)
3733    RD = CXXRecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc,
3734                               /*Id=*/nullptr);
3735  else
3736    RD = RecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc, /*Id=*/nullptr);
3737
3738  RD->setCapturedRecord();
3739  DC->addDecl(RD);
3740  RD->setImplicit();
3741  RD->startDefinition();
3742
3743  assert(NumParams > 0 && "CapturedStmt requires context parameter");
3744  CD = CapturedDecl::Create(Context, CurContext, NumParams);
3745  DC->addDecl(CD);
3746  return RD;
3747}
3748
3749static void buildCapturedStmtCaptureList(
3750    SmallVectorImpl<CapturedStmt::Capture> &Captures,
3751    SmallVectorImpl<Expr *> &CaptureInits,
3752    ArrayRef<CapturingScopeInfo::Capture> Candidates) {
3753
3754  typedef ArrayRef<CapturingScopeInfo::Capture>::const_iterator CaptureIter;
3755  for (CaptureIter Cap = Candidates.begin(); Cap != Candidates.end(); ++Cap) {
3756
3757    if (Cap->isThisCapture()) {
3758      Captures.push_back(CapturedStmt::Capture(Cap->getLocation(),
3759                                               CapturedStmt::VCK_This));
3760      CaptureInits.push_back(Cap->getInitExpr());
3761      continue;
3762    } else if (Cap->isVLATypeCapture()) {
3763      Captures.push_back(
3764          CapturedStmt::Capture(Cap->getLocation(), CapturedStmt::VCK_VLAType));
3765      CaptureInits.push_back(nullptr);
3766      continue;
3767    }
3768
3769    assert(Cap->isReferenceCapture() &&
3770           "non-reference capture not yet implemented");
3771
3772    Captures.push_back(CapturedStmt::Capture(Cap->getLocation(),
3773                                             CapturedStmt::VCK_ByRef,
3774                                             Cap->getVariable()));
3775    CaptureInits.push_back(Cap->getInitExpr());
3776  }
3777}
3778
3779void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
3780                                    CapturedRegionKind Kind,
3781                                    unsigned NumParams) {
3782  CapturedDecl *CD = nullptr;
3783  RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
3784
3785  // Build the context parameter
3786  DeclContext *DC = CapturedDecl::castToDeclContext(CD);
3787  IdentifierInfo *ParamName = &Context.Idents.get("__context");
3788  QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
3789  ImplicitParamDecl *Param
3790    = ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType);
3791  DC->addDecl(Param);
3792
3793  CD->setContextParam(0, Param);
3794
3795  // Enter the capturing scope for this captured region.
3796  PushCapturedRegionScope(CurScope, CD, RD, Kind);
3797
3798  if (CurScope)
3799    PushDeclContext(CurScope, CD);
3800  else
3801    CurContext = CD;
3802
3803  PushExpressionEvaluationContext(PotentiallyEvaluated);
3804}
3805
3806void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
3807                                    CapturedRegionKind Kind,
3808                                    ArrayRef<CapturedParamNameType> Params) {
3809  CapturedDecl *CD = nullptr;
3810  RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, Params.size());
3811
3812  // Build the context parameter
3813  DeclContext *DC = CapturedDecl::castToDeclContext(CD);
3814  bool ContextIsFound = false;
3815  unsigned ParamNum = 0;
3816  for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
3817                                                 E = Params.end();
3818       I != E; ++I, ++ParamNum) {
3819    if (I->second.isNull()) {
3820      assert(!ContextIsFound &&
3821             "null type has been found already for '__context' parameter");
3822      IdentifierInfo *ParamName = &Context.Idents.get("__context");
3823      QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
3824      ImplicitParamDecl *Param
3825        = ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType);
3826      DC->addDecl(Param);
3827      CD->setContextParam(ParamNum, Param);
3828      ContextIsFound = true;
3829    } else {
3830      IdentifierInfo *ParamName = &Context.Idents.get(I->first);
3831      ImplicitParamDecl *Param
3832        = ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second);
3833      DC->addDecl(Param);
3834      CD->setParam(ParamNum, Param);
3835    }
3836  }
3837  assert(ContextIsFound && "no null type for '__context' parameter");
3838  if (!ContextIsFound) {
3839    // Add __context implicitly if it is not specified.
3840    IdentifierInfo *ParamName = &Context.Idents.get("__context");
3841    QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
3842    ImplicitParamDecl *Param =
3843        ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType);
3844    DC->addDecl(Param);
3845    CD->setContextParam(ParamNum, Param);
3846  }
3847  // Enter the capturing scope for this captured region.
3848  PushCapturedRegionScope(CurScope, CD, RD, Kind);
3849
3850  if (CurScope)
3851    PushDeclContext(CurScope, CD);
3852  else
3853    CurContext = CD;
3854
3855  PushExpressionEvaluationContext(PotentiallyEvaluated);
3856}
3857
3858void Sema::ActOnCapturedRegionError() {
3859  DiscardCleanupsInEvaluationContext();
3860  PopExpressionEvaluationContext();
3861
3862  CapturedRegionScopeInfo *RSI = getCurCapturedRegion();
3863  RecordDecl *Record = RSI->TheRecordDecl;
3864  Record->setInvalidDecl();
3865
3866  SmallVector<Decl*, 4> Fields(Record->fields());
3867  ActOnFields(/*Scope=*/nullptr, Record->getLocation(), Record, Fields,
3868              SourceLocation(), SourceLocation(), /*AttributeList=*/nullptr);
3869
3870  PopDeclContext();
3871  PopFunctionScopeInfo();
3872}
3873
3874StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
3875  CapturedRegionScopeInfo *RSI = getCurCapturedRegion();
3876
3877  SmallVector<CapturedStmt::Capture, 4> Captures;
3878  SmallVector<Expr *, 4> CaptureInits;
3879  buildCapturedStmtCaptureList(Captures, CaptureInits, RSI->Captures);
3880
3881  CapturedDecl *CD = RSI->TheCapturedDecl;
3882  RecordDecl *RD = RSI->TheRecordDecl;
3883
3884  CapturedStmt *Res = CapturedStmt::Create(getASTContext(), S,
3885                                           RSI->CapRegionKind, Captures,
3886                                           CaptureInits, CD, RD);
3887
3888  CD->setBody(Res->getCapturedStmt());
3889  RD->completeDefinition();
3890
3891  DiscardCleanupsInEvaluationContext();
3892  PopExpressionEvaluationContext();
3893
3894  PopDeclContext();
3895  PopFunctionScopeInfo();
3896
3897  return Res;
3898}
3899