1//===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===//
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 coordinates the per-module state used while generating code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenModule.h"
15#include "CGDebugInfo.h"
16#include "CodeGenFunction.h"
17#include "CGCall.h"
18#include "CGObjCRuntime.h"
19#include "Mangle.h"
20#include "clang/Frontend/CompileOptions.h"
21#include "clang/AST/ASTContext.h"
22#include "clang/AST/DeclObjC.h"
23#include "clang/AST/DeclCXX.h"
24#include "clang/Basic/Builtins.h"
25#include "clang/Basic/Diagnostic.h"
26#include "clang/Basic/SourceManager.h"
27#include "clang/Basic/TargetInfo.h"
28#include "clang/Basic/ConvertUTF.h"
29#include "llvm/CallingConv.h"
30#include "llvm/Module.h"
31#include "llvm/Intrinsics.h"
32#include "llvm/Target/TargetData.h"
33using namespace clang;
34using namespace CodeGen;
35
36
37CodeGenModule::CodeGenModule(ASTContext &C, const CompileOptions &compileOpts,
38 llvm::Module &M, const llvm::TargetData &TD,
39 Diagnostic &diags)
40 : BlockModule(C, M, TD, Types, *this), Context(C),
41 Features(C.getLangOptions()), CompileOpts(compileOpts), TheModule(M),
42 TheTargetData(TD), Diags(diags), Types(C, M, TD), Runtime(0),
43 MemCpyFn(0), MemMoveFn(0), MemSetFn(0), CFConstantStringClassRef(0) {
44
45 if (!Features.ObjC1)
46 Runtime = 0;
47 else if (!Features.NeXTRuntime)
48 Runtime = CreateGNUObjCRuntime(*this);
49 else if (Features.ObjCNonFragileABI)
50 Runtime = CreateMacNonFragileABIObjCRuntime(*this);
51 else
52 Runtime = CreateMacObjCRuntime(*this);
53
54 // If debug info generation is enabled, create the CGDebugInfo object.
55 DebugInfo = CompileOpts.DebugInfo ? new CGDebugInfo(this) : 0;
56}
57
58CodeGenModule::~CodeGenModule() {
59 delete Runtime;
60 delete DebugInfo;
61}
62
63void CodeGenModule::Release() {
64 EmitDeferred();
65 if (Runtime)
66 if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction())
67 AddGlobalCtor(ObjCInitFunction);
68 EmitCtorList(GlobalCtors, "llvm.global_ctors");
69 EmitCtorList(GlobalDtors, "llvm.global_dtors");
70 EmitAnnotations();
71 EmitLLVMUsed();
72}
73
74/// ErrorUnsupported - Print out an error that codegen doesn't support the
75/// specified stmt yet.
76void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type,
77 bool OmitOnError) {
78 if (OmitOnError && getDiags().hasErrorOccurred())
79 return;
80 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error,
81 "cannot compile this %0 yet");
82 std::string Msg = Type;
83 getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID)
84 << Msg << S->getSourceRange();
85}
86
87/// ErrorUnsupported - Print out an error that codegen doesn't support the
88/// specified decl yet.
89void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type,
90 bool OmitOnError) {
91 if (OmitOnError && getDiags().hasErrorOccurred())
92 return;
93 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error,
94 "cannot compile this %0 yet");
95 std::string Msg = Type;
96 getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
97}
98
99LangOptions::VisibilityMode
100CodeGenModule::getDeclVisibilityMode(const Decl *D) const {
101 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
102 if (VD->getStorageClass() == VarDecl::PrivateExtern)
103 return LangOptions::Hidden;
104
105 if (const VisibilityAttr *attr = D->getAttr()) {
106 switch (attr->getVisibility()) {
107 default: assert(0 && "Unknown visibility!");
108 case VisibilityAttr::DefaultVisibility:
109 return LangOptions::Default;
110 case VisibilityAttr::HiddenVisibility:
111 return LangOptions::Hidden;
112 case VisibilityAttr::ProtectedVisibility:
113 return LangOptions::Protected;
114 }
115 }
116
117 return getLangOptions().getVisibilityMode();
118}
119
120void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
121 const Decl *D) const {
122 // Internal definitions always have default visibility.
123 if (GV->hasLocalLinkage()) {
124 GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
125 return;
126 }
127
128 switch (getDeclVisibilityMode(D)) {
129 default: assert(0 && "Unknown visibility!");
130 case LangOptions::Default:
131 return GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
132 case LangOptions::Hidden:
133 return GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
134 case LangOptions::Protected:
135 return GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
136 }
137}
138
139const char *CodeGenModule::getMangledName(const GlobalDecl &GD) {
140 const NamedDecl *ND = GD.getDecl();
141
142 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND))
143 return getMangledCXXCtorName(D, GD.getCtorType());
144 if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND))
145 return getMangledCXXDtorName(D, GD.getDtorType());
146
147 return getMangledName(ND);
148}
149
150/// \brief Retrieves the mangled name for the given declaration.
151///
152/// If the given declaration requires a mangled name, returns an
153/// const char* containing the mangled name. Otherwise, returns
154/// the unmangled name.
155///
156const char *CodeGenModule::getMangledName(const NamedDecl *ND) {
157 // In C, functions with no attributes never need to be mangled. Fastpath them.
158 if (!getLangOptions().CPlusPlus && !ND->hasAttrs()) {
159 assert(ND->getIdentifier() && "Attempt to mangle unnamed decl.");
160 return ND->getNameAsCString();
161 }
162
163 llvm::SmallString<256> Name;
164 llvm::raw_svector_ostream Out(Name);
165 if (!mangleName(ND, Context, Out)) {
166 assert(ND->getIdentifier() && "Attempt to mangle unnamed decl.");
167 return ND->getNameAsCString();
168 }
169
170 Name += '\0';
171 return UniqueMangledName(Name.begin(), Name.end());
172}
173
174const char *CodeGenModule::UniqueMangledName(const char *NameStart,
175 const char *NameEnd) {
176 assert(*(NameEnd - 1) == '\0' && "Mangled name must be null terminated!");
177
178 return MangledNames.GetOrCreateValue(NameStart, NameEnd).getKeyData();
179}
180
181/// AddGlobalCtor - Add a function to the list that will be called before
182/// main() runs.
183void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) {
184 // FIXME: Type coercion of void()* types.
185 GlobalCtors.push_back(std::make_pair(Ctor, Priority));
186}
187
188/// AddGlobalDtor - Add a function to the list that will be called
189/// when the module is unloaded.
190void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) {
191 // FIXME: Type coercion of void()* types.
192 GlobalDtors.push_back(std::make_pair(Dtor, Priority));
193}
194
195void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) {
196 // Ctor function type is void()*.
197 llvm::FunctionType* CtorFTy =
198 llvm::FunctionType::get(llvm::Type::VoidTy,
199 std::vector<const llvm::Type*>(),
200 false);
201 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy);
202
203 // Get the type of a ctor entry, { i32, void ()* }.
204 llvm::StructType* CtorStructTy =
205 llvm::StructType::get(llvm::Type::Int32Ty,
206 llvm::PointerType::getUnqual(CtorFTy), NULL);
207
208 // Construct the constructor and destructor arrays.
209 std::vector<llvm::Constant*> Ctors;
210 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
211 std::vector<llvm::Constant*> S;
212 S.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, I->second, false));
213 S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy));
214 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S));
215 }
216
217 if (!Ctors.empty()) {
218 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size());
219 new llvm::GlobalVariable(AT, false,
220 llvm::GlobalValue::AppendingLinkage,
221 llvm::ConstantArray::get(AT, Ctors),
222 GlobalName,
223 &TheModule);
224 }
225}
226
227void CodeGenModule::EmitAnnotations() {
228 if (Annotations.empty())
229 return;
230
231 // Create a new global variable for the ConstantStruct in the Module.
232 llvm::Constant *Array =
233 llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(),
234 Annotations.size()),
235 Annotations);
236 llvm::GlobalValue *gv =
237 new llvm::GlobalVariable(Array->getType(), false,
238 llvm::GlobalValue::AppendingLinkage, Array,
239 "llvm.global.annotations", &TheModule);
240 gv->setSection("llvm.metadata");
241}
242
243static CodeGenModule::GVALinkage
244GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
245 const LangOptions &Features) {
246 // The kind of external linkage this function will have, if it is not
247 // inline or static.
248 CodeGenModule::GVALinkage External = CodeGenModule::GVA_StrongExternal;
249 if (Context.getLangOptions().CPlusPlus &&
250 (FD->getPrimaryTemplate() || FD->getInstantiatedFromMemberFunction()) &&
251 !FD->isExplicitSpecialization())
252 External = CodeGenModule::GVA_TemplateInstantiation;
253
254 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
255 // C++ member functions defined inside the class are always inline.
256 if (MD->isInline() || !MD->isOutOfLine())
257 return CodeGenModule::GVA_CXXInline;
258
259 return External;
260 }
261
262 // "static" functions get internal linkage.
263 if (FD->getStorageClass() == FunctionDecl::Static)
264 return CodeGenModule::GVA_Internal;
265
266 if (!FD->isInline())
267 return External;
268
269 // If the inline function explicitly has the GNU inline attribute on it, or if
270 // this is C89 mode, we use to GNU semantics.
271 if (!Features.C99 && !Features.CPlusPlus) {
272 // extern inline in GNU mode is like C99 inline.
273 if (FD->getStorageClass() == FunctionDecl::Extern)
274 return CodeGenModule::GVA_C99Inline;
275 // Normal inline is a strong symbol.
276 return CodeGenModule::GVA_StrongExternal;
277 } else if (FD->hasActiveGNUInlineAttribute(Context)) {
278 // GCC in C99 mode seems to use a different decision-making
279 // process for extern inline, which factors in previous
280 // declarations.
281 if (FD->isExternGNUInline(Context))
282 return CodeGenModule::GVA_C99Inline;
283 // Normal inline is a strong symbol.
284 return External;
285 }
286
287 // The definition of inline changes based on the language. Note that we
288 // have already handled "static inline" above, with the GVA_Internal case.
289 if (Features.CPlusPlus) // inline and extern inline.
290 return CodeGenModule::GVA_CXXInline;
291
292 assert(Features.C99 && "Must be in C99 mode if not in C89 or C++ mode");
293 if (FD->isC99InlineDefinition())
294 return CodeGenModule::GVA_C99Inline;
295
296 return CodeGenModule::GVA_StrongExternal;
297}
298
299/// SetFunctionDefinitionAttributes - Set attributes for a global.
300///
301/// FIXME: This is currently only done for aliases and functions, but not for
302/// variables (these details are set in EmitGlobalVarDefinition for variables).
303void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
304 llvm::GlobalValue *GV) {
305 GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
306
307 if (Linkage == GVA_Internal) {
308 GV->setLinkage(llvm::Function::InternalLinkage);
309 } else if (D->hasAttr()) {
310 GV->setLinkage(llvm::Function::DLLExportLinkage);
311 } else if (D->hasAttr()) {
312 GV->setLinkage(llvm::Function::WeakAnyLinkage);
313 } else if (Linkage == GVA_C99Inline) {
314 // In C99 mode, 'inline' functions are guaranteed to have a strong
315 // definition somewhere else, so we can use available_externally linkage.
316 GV->setLinkage(llvm::Function::AvailableExternallyLinkage);
317 } else if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) {
318 // In C++, the compiler has to emit a definition in every translation unit
319 // that references the function. We should use linkonce_odr because
320 // a) if all references in this translation unit are optimized away, we
321 // don't need to codegen it. b) if the function persists, it needs to be
322 // merged with other definitions. c) C++ has the ODR, so we know the
323 // definition is dependable.
324 GV->setLinkage(llvm::Function::LinkOnceODRLinkage);
325 } else {
326 assert(Linkage == GVA_StrongExternal);
327 // Otherwise, we have strong external linkage.
328 GV->setLinkage(llvm::Function::ExternalLinkage);
329 }
330
331 SetCommonAttributes(D, GV);
332}
333
334void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D,
335 const CGFunctionInfo &Info,
336 llvm::Function *F) {
337 AttributeListType AttributeList;
338 ConstructAttributeList(Info, D, AttributeList);
339
340 F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(),
341 AttributeList.size()));
342
343 // Set the appropriate calling convention for the Function.
344 if (D->hasAttr())
345 F->setCallingConv(llvm::CallingConv::X86_FastCall);
346
347 if (D->hasAttr())
348 F->setCallingConv(llvm::CallingConv::X86_StdCall);
349}
350
351void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
352 llvm::Function *F) {
353 if (!Features.Exceptions && !Features.ObjCNonFragileABI)
354 F->addFnAttr(llvm::Attribute::NoUnwind);
355
356 if (D->hasAttr())
357 F->addFnAttr(llvm::Attribute::AlwaysInline);
358
359 if (D->hasAttr())
360 F->addFnAttr(llvm::Attribute::NoInline);
361}
362
363void CodeGenModule::SetCommonAttributes(const Decl *D,
364 llvm::GlobalValue *GV) {
365 setGlobalVisibility(GV, D);
366
367 if (D->hasAttr())
368 AddUsedGlobal(GV);
369
370 if (const SectionAttr *SA = D->getAttr())
371 GV->setSection(SA->getName());
372}
373
374void CodeGenModule::SetInternalFunctionAttributes(const Decl *D,
375 llvm::Function *F,
376 const CGFunctionInfo &FI) {
377 SetLLVMFunctionAttributes(D, FI, F);
378 SetLLVMFunctionAttributesForDefinition(D, F);
379
380 F->setLinkage(llvm::Function::InternalLinkage);
381
382 SetCommonAttributes(D, F);
383}
384
385void CodeGenModule::SetFunctionAttributes(const FunctionDecl *FD,
386 llvm::Function *F,
387 bool IsIncompleteFunction) {
388 if (!IsIncompleteFunction)
389 SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(FD), F);
390
391 // Only a few attributes are set on declarations; these may later be
392 // overridden by a definition.
393
394 if (FD->hasAttr()) {
395 F->setLinkage(llvm::Function::DLLImportLinkage);
396 } else if (FD->hasAttr() ||
397 FD->hasAttr()) {
398 // "extern_weak" is overloaded in LLVM; we probably should have
399 // separate linkage types for this.
400 F->setLinkage(llvm::Function::ExternalWeakLinkage);
401 } else {
402 F->setLinkage(llvm::Function::ExternalLinkage);
403 }
404
405 if (const SectionAttr *SA = FD->getAttr())
406 F->setSection(SA->getName());
407}
408
409void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) {
410 assert(!GV->isDeclaration() &&
411 "Only globals with definition can force usage.");
412 LLVMUsed.push_back(GV);
413}
414
415void CodeGenModule::EmitLLVMUsed() {
416 // Don't create llvm.used if there is no need.
417 // FIXME. Runtime indicates that there might be more 'used' symbols; but not
418 // necessariy. So, this test is not accurate for emptiness.
419 if (LLVMUsed.empty() && !Runtime)
420 return;
421
422 llvm::Type *i8PTy = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
423
424 // Convert LLVMUsed to what ConstantArray needs.
425 std::vector<llvm::Constant*> UsedArray;
426 UsedArray.resize(LLVMUsed.size());
427 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) {
428 UsedArray[i] =
429 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), i8PTy);
430 }
431
432 if (Runtime)
433 Runtime->MergeMetadataGlobals(UsedArray);
434 if (UsedArray.empty())
435 return;
436 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size());
437
438 llvm::GlobalVariable *GV =
439 new llvm::GlobalVariable(ATy, false,
440 llvm::GlobalValue::AppendingLinkage,
441 llvm::ConstantArray::get(ATy, UsedArray),
442 "llvm.used", &getModule());
443
444 GV->setSection("llvm.metadata");
445}
446
447void CodeGenModule::EmitDeferred() {
448 // Emit code for any potentially referenced deferred decls. Since a
449 // previously unused static decl may become used during the generation of code
450 // for a static function, iterate until no changes are made.
451 while (!DeferredDeclsToEmit.empty()) {
452 GlobalDecl D = DeferredDeclsToEmit.back();
453 DeferredDeclsToEmit.pop_back();
454
455 // The mangled name for the decl must have been emitted in GlobalDeclMap.
456 // Look it up to see if it was defined with a stronger definition (e.g. an
457 // extern inline function with a strong function redefinition). If so,
458 // just ignore the deferred decl.
459 llvm::GlobalValue *CGRef = GlobalDeclMap[getMangledName(D)];
460 assert(CGRef && "Deferred decl wasn't referenced?");
461
462 if (!CGRef->isDeclaration())
463 continue;
464
465 // Otherwise, emit the definition and move on to the next one.
466 EmitGlobalDefinition(D);
467 }
468}
469
470/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the
471/// annotation information for a given GlobalValue. The annotation struct is
472/// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the
473/// GlobalValue being annotated. The second field is the constant string
474/// created from the AnnotateAttr's annotation. The third field is a constant
475/// string containing the name of the translation unit. The fourth field is
476/// the line number in the file of the annotated value declaration.
477///
478/// FIXME: this does not unique the annotation string constants, as llvm-gcc
479/// appears to.
480///
481llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
482 const AnnotateAttr *AA,
483 unsigned LineNo) {
484 llvm::Module *M = &getModule();
485
486 // get [N x i8] constants for the annotation string, and the filename string
487 // which are the 2nd and 3rd elements of the global annotation structure.
488 const llvm::Type *SBP = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
489 llvm::Constant *anno = llvm::ConstantArray::get(AA->getAnnotation(), true);
490 llvm::Constant *unit = llvm::ConstantArray::get(M->getModuleIdentifier(),
491 true);
492
493 // Get the two global values corresponding to the ConstantArrays we just
494 // created to hold the bytes of the strings.
495 const char *StringPrefix = getContext().Target.getStringSymbolPrefix(true);
496 llvm::GlobalValue *annoGV =
497 new llvm::GlobalVariable(anno->getType(), false,
498 llvm::GlobalValue::InternalLinkage, anno,
499 GV->getName() + StringPrefix, M);
500 // translation unit name string, emitted into the llvm.metadata section.
501 llvm::GlobalValue *unitGV =
502 new llvm::GlobalVariable(unit->getType(), false,
503 llvm::GlobalValue::InternalLinkage, unit,
504 StringPrefix, M);
505
506 // Create the ConstantStruct for the global annotation.
507 llvm::Constant *Fields[4] = {
508 llvm::ConstantExpr::getBitCast(GV, SBP),
509 llvm::ConstantExpr::getBitCast(annoGV, SBP),
510 llvm::ConstantExpr::getBitCast(unitGV, SBP),
511 llvm::ConstantInt::get(llvm::Type::Int32Ty, LineNo)
512 };
513 return llvm::ConstantStruct::get(Fields, 4, false);
514}
515
516bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) {
517 // Never defer when EmitAllDecls is specified or the decl has
518 // attribute used.
519 if (Features.EmitAllDecls || Global->hasAttr())
520 return false;
521
522 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
523 // Constructors and destructors should never be deferred.
524 if (FD->hasAttr() ||
525 FD->hasAttr())
526 return false;
527
528 GVALinkage Linkage = GetLinkageForFunction(getContext(), FD, Features);
529
530 // static, static inline, always_inline, and extern inline functions can
531 // always be deferred. Normal inline functions can be deferred in C99/C++.
532 if (Linkage == GVA_Internal || Linkage == GVA_C99Inline ||
533 Linkage == GVA_CXXInline)
534 return true;
535 return false;
536 }
537
538 const VarDecl *VD = cast<VarDecl>(Global);
539 assert(VD->isFileVarDecl() && "Invalid decl");
540
541 return VD->getStorageClass() == VarDecl::Static;
542}
543
544void CodeGenModule::EmitGlobal(GlobalDecl GD) {
545 const ValueDecl *Global = GD.getDecl();
546
547 // If this is an alias definition (which otherwise looks like a declaration)
548 // emit it now.
549 if (Global->hasAttr())
550 return EmitAliasDefinition(Global);
551
552 // Ignore declarations, they will be emitted on their first use.
553 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
554 // Forward declarations are emitted lazily on first use.
555 if (!FD->isThisDeclarationADefinition())
556 return;
557 } else {
558 const VarDecl *VD = cast<VarDecl>(Global);
559 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
560
561 // In C++, if this is marked "extern", defer code generation.
562 if (getLangOptions().CPlusPlus && !VD->getInit() &&
563 (VD->getStorageClass() == VarDecl::Extern ||
564 VD->isExternC(getContext())))
565 return;
566
567 // In C, if this isn't a definition, defer code generation.
568 if (!getLangOptions().CPlusPlus && !VD->getInit())
569 return;
570 }
571
572 // Defer code generation when possible if this is a static definition, inline
573 // function etc. These we only want to emit if they are used.
574 if (MayDeferGeneration(Global)) {
575 // If the value has already been used, add it directly to the
576 // DeferredDeclsToEmit list.
577 const char *MangledName = getMangledName(GD);
578 if (GlobalDeclMap.count(MangledName))
579 DeferredDeclsToEmit.push_back(GD);
580 else {
581 // Otherwise, remember that we saw a deferred decl with this name. The
582 // first use of the mangled name will cause it to move into
583 // DeferredDeclsToEmit.
584 DeferredDecls[MangledName] = GD;
585 }
586 return;
587 }
588
589 // Otherwise emit the definition.
590 EmitGlobalDefinition(GD);
591}
592
593void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
594 const ValueDecl *D = GD.getDecl();
595
596 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
597 EmitCXXConstructor(CD, GD.getCtorType());
598 else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(D))
599 EmitCXXDestructor(DD, GD.getDtorType());
600 else if (isa<FunctionDecl>(D))
601 EmitGlobalFunctionDefinition(GD);
602 else if (const VarDecl *VD = dyn_cast<VarDecl>(D))
603 EmitGlobalVarDefinition(VD);
604 else {
605 assert(0 && "Invalid argument to EmitGlobalDefinition()");
606 }
607}
608
609/// GetOrCreateLLVMFunction - If the specified mangled name is not in the
610/// module, create and return an llvm Function with the specified type. If there
611/// is something in the module with the specified name, return it potentially
612/// bitcasted to the right type.
613///
614/// If D is non-null, it specifies a decl that correspond to this. This is used
615/// to set the attributes on the function when it is first created.
616llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(const char *MangledName,
617 const llvm::Type *Ty,
618 GlobalDecl D) {
619 // Lookup the entry, lazily creating it if necessary.
620 llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
621 if (Entry) {
622 if (Entry->getType()->getElementType() == Ty)
623 return Entry;
624
625 // Make sure the result is of the correct type.
626 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
627 return llvm::ConstantExpr::getBitCast(Entry, PTy);
628 }
629
630 // This is the first use or definition of a mangled name. If there is a
631 // deferred decl with this name, remember that we need to emit it at the end
632 // of the file.
633 llvm::DenseMap<const char*, GlobalDecl>::iterator DDI =
634 DeferredDecls.find(MangledName);
635 if (DDI != DeferredDecls.end()) {
636 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
637 // list, and remove it from DeferredDecls (since we don't need it anymore).
638 DeferredDeclsToEmit.push_back(DDI->second);
639 DeferredDecls.erase(DDI);
640 } else if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl())) {
641 // If this the first reference to a C++ inline function in a class, queue up
642 // the deferred function body for emission. These are not seen as
643 // top-level declarations.
644 if (FD->isThisDeclarationADefinition() && MayDeferGeneration(FD))
645 DeferredDeclsToEmit.push_back(D);
646 }
647
648 // This function doesn't have a complete type (for example, the return
649 // type is an incomplete struct). Use a fake type instead, and make
650 // sure not to try to set attributes.
651 bool IsIncompleteFunction = false;
652 if (!isa<llvm::FunctionType>(Ty)) {
653 Ty = llvm::FunctionType::get(llvm::Type::VoidTy,
654 std::vector<const llvm::Type*>(), false);
655 IsIncompleteFunction = true;
656 }
657 llvm::Function *F = llvm::Function::Create(cast<llvm::FunctionType>(Ty),
658 llvm::Function::ExternalLinkage,
659 "", &getModule());
660 F->setName(MangledName);
661 if (D.getDecl())
662 SetFunctionAttributes(cast<FunctionDecl>(D.getDecl()), F,
663 IsIncompleteFunction);
664 Entry = F;
665 return F;
666}
667
668/// GetAddrOfFunction - Return the address of the given function. If Ty is
669/// non-null, then this function will use the specified type if it has to
670/// create it (this occurs when we see a definition of the function).
671llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD,
672 const llvm::Type *Ty) {
673 // If there was no specific requested type, just convert it now.
674 if (!Ty)
675 Ty = getTypes().ConvertType(GD.getDecl()->getType());
676 return GetOrCreateLLVMFunction(getMangledName(GD.getDecl()), Ty, GD);
677}
678
679/// CreateRuntimeFunction - Create a new runtime function with the specified
680/// type and name.
681llvm::Constant *
682CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy,
683 const char *Name) {
684 // Convert Name to be a uniqued string from the IdentifierInfo table.
685 Name = getContext().Idents.get(Name).getName();
686 return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl());
687}
688
689/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
690/// create and return an llvm GlobalVariable with the specified type. If there
691/// is something in the module with the specified name, return it potentially
692/// bitcasted to the right type.
693///
694/// If D is non-null, it specifies a decl that correspond to this. This is used
695/// to set the attributes on the global when it is first created.
696llvm::Constant *CodeGenModule::GetOrCreateLLVMGlobal(const char *MangledName,
697 const llvm::PointerType*Ty,
698 const VarDecl *D) {
699 // Lookup the entry, lazily creating it if necessary.
700 llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
701 if (Entry) {
702 if (Entry->getType() == Ty)
703 return Entry;
704
705 // Make sure the result is of the correct type.
706 return llvm::ConstantExpr::getBitCast(Entry, Ty);
707 }
708
709 // This is the first use or definition of a mangled name. If there is a
710 // deferred decl with this name, remember that we need to emit it at the end
711 // of the file.
712 llvm::DenseMap<const char*, GlobalDecl>::iterator DDI =
713 DeferredDecls.find(MangledName);
714 if (DDI != DeferredDecls.end()) {
715 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
716 // list, and remove it from DeferredDecls (since we don't need it anymore).
717 DeferredDeclsToEmit.push_back(DDI->second);
718 DeferredDecls.erase(DDI);
719 }
720
721 llvm::GlobalVariable *GV =
722 new llvm::GlobalVariable(Ty->getElementType(), false,
723 llvm::GlobalValue::ExternalLinkage,
724 0, "", &getModule(),
725 false, Ty->getAddressSpace());
726 GV->setName(MangledName);
727
728 // Handle things which are present even on external declarations.
729 if (D) {
730 // FIXME: This code is overly simple and should be merged with other global
731 // handling.
732 GV->setConstant(D->getType().isConstant(Context));
733
734 // FIXME: Merge with other attribute handling code.
735 if (D->getStorageClass() == VarDecl::PrivateExtern)
736 GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
737
738 if (D->hasAttr() ||
739 D->hasAttr())
740 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
741
742 GV->setThreadLocal(D->isThreadSpecified());
743 }
744
745 return Entry = GV;
746}
747
748
749/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
750/// given global variable. If Ty is non-null and if the global doesn't exist,
751/// then it will be greated with the specified type instead of whatever the
752/// normal requested type would be.
753llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
754 const llvm::Type *Ty) {
755 assert(D->hasGlobalStorage() && "Not a global variable");
756 QualType ASTTy = D->getType();
757 if (Ty == 0)
758 Ty = getTypes().ConvertTypeForMem(ASTTy);
759
760 const llvm::PointerType *PTy =
761 llvm::PointerType::get(Ty, ASTTy.getAddressSpace());
762 return GetOrCreateLLVMGlobal(getMangledName(D), PTy, D);
763}
764
765/// CreateRuntimeVariable - Create a new runtime global variable with the
766/// specified type and name.
767llvm::Constant *
768CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty,
769 const char *Name) {
770 // Convert Name to be a uniqued string from the IdentifierInfo table.
771 Name = getContext().Idents.get(Name).getName();
772 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0);
773}
774
775void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
776 assert(!D->getInit() && "Cannot emit definite definitions here!");
777
778 if (MayDeferGeneration(D)) {
779 // If we have not seen a reference to this variable yet, place it
780 // into the deferred declarations table to be emitted if needed
781 // later.
782 const char *MangledName = getMangledName(D);
783 if (GlobalDeclMap.count(MangledName) == 0) {
784 DeferredDecls[MangledName] = GlobalDecl(D);
785 return;
786 }
787 }
788
789 // The tentative definition is the only definition.
790 EmitGlobalVarDefinition(D);
791}
792
793void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
794 llvm::Constant *Init = 0;
795 QualType ASTTy = D->getType();
796
797 if (D->getInit() == 0) {
798 // This is a tentative definition; tentative definitions are
799 // implicitly initialized with { 0 }.
800 //
801 // Note that tentative definitions are only emitted at the end of
802 // a translation unit, so they should never have incomplete
803 // type. In addition, EmitTentativeDefinition makes sure that we
804 // never attempt to emit a tentative definition if a real one
805 // exists. A use may still exists, however, so we still may need
806 // to do a RAUW.
807 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type");
808 Init = llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(ASTTy));
809 } else {
810 Init = EmitConstantExpr(D->getInit(), D->getType());
811 if (!Init) {
812 ErrorUnsupported(D, "static initializer");
813 QualType T = D->getInit()->getType();
814 Init = llvm::UndefValue::get(getTypes().ConvertType(T));
815 }
816 }
817
818 const llvm::Type* InitType = Init->getType();
819 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType);
820
821 // Strip off a bitcast if we got one back.
822 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) {
823 assert(CE->getOpcode() == llvm::Instruction::BitCast);
824 Entry = CE->getOperand(0);
825 }
826
827 // Entry is now either a Function or GlobalVariable.
828 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry);
829
830 // We have a definition after a declaration with the wrong type.
831 // We must make a new GlobalVariable* and update everything that used OldGV
832 // (a declaration or tentative definition) with the new GlobalVariable*
833 // (which will be a definition).
834 //
835 // This happens if there is a prototype for a global (e.g.
836 // "extern int x[];") and then a definition of a different type (e.g.
837 // "int x[10];"). This also happens when an initializer has a different type
838 // from the type of the global (this happens with unions).
839 if (GV == 0 ||
840 GV->getType()->getElementType() != InitType ||
841 GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) {
842
843 // Remove the old entry from GlobalDeclMap so that we'll create a new one.
844 GlobalDeclMap.erase(getMangledName(D));
845
846 // Make a new global with the correct type, this is now guaranteed to work.
847 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType));
848 GV->takeName(cast<llvm::GlobalValue>(Entry));
849
850 // Replace all uses of the old global with the new global
851 llvm::Constant *NewPtrForOldDecl =
852 llvm::ConstantExpr::getBitCast(GV, Entry->getType());
853 Entry->replaceAllUsesWith(NewPtrForOldDecl);
854
855 // Erase the old global, since it is no longer used.
856 cast<llvm::GlobalValue>(Entry)->eraseFromParent();
857 }
858
859 if (const AnnotateAttr *AA = D->getAttr()) {
860 SourceManager &SM = Context.getSourceManager();
861 AddAnnotation(EmitAnnotateAttr(GV, AA,
862 SM.getInstantiationLineNumber(D->getLocation())));
863 }
864
865 GV->setInitializer(Init);
866 GV->setConstant(D->getType().isConstant(Context));
867 GV->setAlignment(getContext().getDeclAlignInBytes(D));
868
869 // Set the llvm linkage type as appropriate.
870 if (D->getStorageClass() == VarDecl::Static)
871 GV->setLinkage(llvm::Function::InternalLinkage);
872 else if (D->hasAttr())
873 GV->setLinkage(llvm::Function::DLLImportLinkage);
874 else if (D->hasAttr())
875 GV->setLinkage(llvm::Function::DLLExportLinkage);
876 else if (D->hasAttr())
877 GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
878 else if (!CompileOpts.NoCommon &&
879 (!D->hasExternalStorage() && !D->getInit()))
880 GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
881 else
882 GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
883
884 SetCommonAttributes(D, GV);
885
886 // Emit global variable debug information.
887 if (CGDebugInfo *DI = getDebugInfo()) {
888 DI->setLocation(D->getLocation());
889 DI->EmitGlobalVariable(GV, D);
890 }
891}
892
893/// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we
894/// implement a function with no prototype, e.g. "int foo() {}". If there are
895/// existing call uses of the old function in the module, this adjusts them to
896/// call the new function directly.
897///
898/// This is not just a cleanup: the always_inline pass requires direct calls to
899/// functions to be able to inline them. If there is a bitcast in the way, it
900/// won't inline them. Instcombine normally deletes these calls, but it isn't
901/// run at -O0.
902static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
903 llvm::Function *NewFn) {
904 // If we're redefining a global as a function, don't transform it.
905 llvm::Function *OldFn = dyn_cast<llvm::Function>(Old);
906 if (OldFn == 0) return;
907
908 const llvm::Type *NewRetTy = NewFn->getReturnType();
909 llvm::SmallVector<llvm::Value*, 4> ArgList;
910
911 for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end();
912 UI != E; ) {
913 // TODO: Do invokes ever occur in C code? If so, we should handle them too.
914 unsigned OpNo = UI.getOperandNo();
915 llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*UI++);
916 if (!CI || OpNo != 0) continue;
917
918 // If the return types don't match exactly, and if the call isn't dead, then
919 // we can't transform this call.
920 if (CI->getType() != NewRetTy && !CI->use_empty())
921 continue;
922
923 // If the function was passed too few arguments, don't transform. If extra
924 // arguments were passed, we silently drop them. If any of the types
925 // mismatch, we don't transform.
926 unsigned ArgNo = 0;
927 bool DontTransform = false;
928 for (llvm::Function::arg_iterator AI = NewFn->arg_begin(),
929 E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) {
930 if (CI->getNumOperands()-1 == ArgNo ||
931 CI->getOperand(ArgNo+1)->getType() != AI->getType()) {
932 DontTransform = true;
933 break;
934 }
935 }
936 if (DontTransform)
937 continue;
938
939 // Okay, we can transform this. Create the new call instruction and copy
940 // over the required information.
941 ArgList.append(CI->op_begin()+1, CI->op_begin()+1+ArgNo);
942 llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(),
943 ArgList.end(), "", CI);
944 ArgList.clear();
945 if (NewCall->getType() != llvm::Type::VoidTy)
946 NewCall->takeName(CI);
947 NewCall->setCallingConv(CI->getCallingConv());
948 NewCall->setAttributes(CI->getAttributes());
949
950 // Finally, remove the old call, replacing any uses with the new one.
951 if (!CI->use_empty())
952 CI->replaceAllUsesWith(NewCall);
953 CI->eraseFromParent();
954 }
955}
956
957
958void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) {
959 const llvm::FunctionType *Ty;
960 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl());
961
962 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
963 bool isVariadic = D->getType()->getAsFunctionProtoType()->isVariadic();
964
965 Ty = getTypes().GetFunctionType(getTypes().getFunctionInfo(MD), isVariadic);
966 } else {
967 Ty = cast<llvm::FunctionType>(getTypes().ConvertType(D->getType()));
968
969 // As a special case, make sure that definitions of K&R function
970 // "type foo()" aren't declared as varargs (which forces the backend
971 // to do unnecessary work).
972 if (D->getType()->isFunctionNoProtoType()) {
973 assert(Ty->isVarArg() && "Didn't lower type as expected");
974 // Due to stret, the lowered function could have arguments.
975 // Just create the same type as was lowered by ConvertType
976 // but strip off the varargs bit.
977 std::vector<const llvm::Type*> Args(Ty->param_begin(), Ty->param_end());
978 Ty = llvm::FunctionType::get(Ty->getReturnType(), Args, false);
979 }
980 }
981
982 // Get or create the prototype for the function.
983 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty);
984
985 // Strip off a bitcast if we got one back.
986 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) {
987 assert(CE->getOpcode() == llvm::Instruction::BitCast);
988 Entry = CE->getOperand(0);
989 }
990
991
992 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) {
993 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry);
994
995 // If the types mismatch then we have to rewrite the definition.
996 assert(OldFn->isDeclaration() &&
997 "Shouldn't replace non-declaration");
998
999 // F is the Function* for the one with the wrong type, we must make a new
1000 // Function* and update everything that used F (a declaration) with the new
1001 // Function* (which will be a definition).
1002 //
1003 // This happens if there is a prototype for a function
1004 // (e.g. "int f()") and then a definition of a different type
1005 // (e.g. "int f(int x)"). Start by making a new function of the
1006 // correct type, RAUW, then steal the name.
1007 GlobalDeclMap.erase(getMangledName(D));
1008 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty));
1009 NewFn->takeName(OldFn);
1010
1011 // If this is an implementation of a function without a prototype, try to
1012 // replace any existing uses of the function (which may be calls) with uses
1013 // of the new function
1014 if (D->getType()->isFunctionNoProtoType()) {
1015 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn);
1016 OldFn->removeDeadConstantUsers();
1017 }
1018
1019 // Replace uses of F with the Function we will endow with a body.
1020 if (!Entry->use_empty()) {
1021 llvm::Constant *NewPtrForOldDecl =
1022 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType());
1023 Entry->replaceAllUsesWith(NewPtrForOldDecl);
1024 }
1025
1026 // Ok, delete the old function now, which is dead.
1027 OldFn->eraseFromParent();
1028
1029 Entry = NewFn;
1030 }
1031
1032 llvm::Function *Fn = cast<llvm::Function>(Entry);
1033
1034 CodeGenFunction(*this).GenerateCode(D, Fn);
1035
1036 SetFunctionDefinitionAttributes(D, Fn);
1037 SetLLVMFunctionAttributesForDefinition(D, Fn);
1038
1039 if (const ConstructorAttr *CA = D->getAttr())
1040 AddGlobalCtor(Fn, CA->getPriority());
1041 if (const DestructorAttr *DA = D->getAttr())
1042 AddGlobalDtor(Fn, DA->getPriority());
1043}
1044
1045void CodeGenModule::EmitAliasDefinition(const ValueDecl *D) {
1046 const AliasAttr *AA = D->getAttr();
1047 assert(AA && "Not an alias?");
1048
1049 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
1050
1051 // Unique the name through the identifier table.
1052 const char *AliaseeName = AA->getAliasee().c_str();
1053 AliaseeName = getContext().Idents.get(AliaseeName).getName();
1054
1055 // Create a reference to the named value. This ensures that it is emitted
1056 // if a deferred decl.
1057 llvm::Constant *Aliasee;
1058 if (isa<llvm::FunctionType>(DeclTy))
1059 Aliasee = GetOrCreateLLVMFunction(AliaseeName, DeclTy, GlobalDecl());
1060 else
1061 Aliasee = GetOrCreateLLVMGlobal(AliaseeName,
1062 llvm::PointerType::getUnqual(DeclTy), 0);
1063
1064 // Create the new alias itself, but don't set a name yet.
1065 llvm::GlobalValue *GA =
1066 new llvm::GlobalAlias(Aliasee->getType(),
1067 llvm::Function::ExternalLinkage,
1068 "", Aliasee, &getModule());
1069
1070 // See if there is already something with the alias' name in the module.
1071 const char *MangledName = getMangledName(D);
1072 llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
1073
1074 if (Entry && !Entry->isDeclaration()) {
1075 // If there is a definition in the module, then it wins over the alias.
1076 // This is dubious, but allow it to be safe. Just ignore the alias.
1077 GA->eraseFromParent();
1078 return;
1079 }
1080
1081 if (Entry) {
1082 // If there is a declaration in the module, then we had an extern followed
1083 // by the alias, as in:
1084 // extern int test6();
1085 // ...
1086 // int test6() __attribute__((alias("test7")));
1087 //
1088 // Remove it and replace uses of it with the alias.
1089
1090 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA,
1091 Entry->getType()));
1092 Entry->eraseFromParent();
1093 }
1094
1095 // Now we know that there is no conflict, set the name.
1096 Entry = GA;
1097 GA->setName(MangledName);
1098
1099 // Set attributes which are particular to an alias; this is a
1100 // specialization of the attributes which may be set on a global
1101 // variable/function.
1102 if (D->hasAttr()) {
1103 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
1104 // The dllexport attribute is ignored for undefined symbols.
1105 if (FD->getBody())
1106 GA->setLinkage(llvm::Function::DLLExportLinkage);
1107 } else {
1108 GA->setLinkage(llvm::Function::DLLExportLinkage);
1109 }
1110 } else if (D->hasAttr() ||
1111 D->hasAttr()) {
1112 GA->setLinkage(llvm::Function::WeakAnyLinkage);
1113 }
1114
1115 SetCommonAttributes(D, GA);
1116}
1117
1118/// getBuiltinLibFunction - Given a builtin id for a function like
1119/// "__builtin_fabsf", return a Function* for "fabsf".
1120llvm::Value *CodeGenModule::getBuiltinLibFunction(unsigned BuiltinID) {
1121 assert((Context.BuiltinInfo.isLibFunction(BuiltinID) ||
1122 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) &&
1123 "isn't a lib fn");
1124
1125 // Get the name, skip over the __builtin_ prefix (if necessary).
1126 const char *Name = Context.BuiltinInfo.GetName(BuiltinID);
1127 if (Context.BuiltinInfo.isLibFunction(BuiltinID))
1128 Name += 10;
1129
1130 // Get the type for the builtin.
1131 ASTContext::GetBuiltinTypeError Error;
1132 QualType Type = Context.GetBuiltinType(BuiltinID, Error);
1133 assert(Error == ASTContext::GE_None && "Can't get builtin type");
1134
1135 const llvm::FunctionType *Ty =
1136 cast<llvm::FunctionType>(getTypes().ConvertType(Type));
1137
1138 // Unique the name through the identifier table.
1139 Name = getContext().Idents.get(Name).getName();
1140 // FIXME: param attributes for sext/zext etc.
1141 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl());
1142}
1143
1144llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys,
1145 unsigned NumTys) {
1146 return llvm::Intrinsic::getDeclaration(&getModule(),
1147 (llvm::Intrinsic::ID)IID, Tys, NumTys);
1148}
1149
1150llvm::Function *CodeGenModule::getMemCpyFn() {
1151 if (MemCpyFn) return MemCpyFn;
1152 const llvm::Type *IntPtr = TheTargetData.getIntPtrType();
1153 return MemCpyFn = getIntrinsic(llvm::Intrinsic::memcpy, &IntPtr, 1);
1154}
1155
1156llvm::Function *CodeGenModule::getMemMoveFn() {
1157 if (MemMoveFn) return MemMoveFn;
1158 const llvm::Type *IntPtr = TheTargetData.getIntPtrType();
1159 return MemMoveFn = getIntrinsic(llvm::Intrinsic::memmove, &IntPtr, 1);
1160}
1161
1162llvm::Function *CodeGenModule::getMemSetFn() {
1163 if (MemSetFn) return MemSetFn;
1164 const llvm::Type *IntPtr = TheTargetData.getIntPtrType();
1165 return MemSetFn = getIntrinsic(llvm::Intrinsic::memset, &IntPtr, 1);
1166}
1167
1168static void appendFieldAndPadding(CodeGenModule &CGM,
1169 std::vector<llvm::Constant*>& Fields,
1170 FieldDecl *FieldD, FieldDecl *NextFieldD,
1171 llvm::Constant* Field,
1172 RecordDecl* RD, const llvm::StructType *STy) {
1173 // Append the field.
1174 Fields.push_back(Field);
1175
1176 int StructFieldNo = CGM.getTypes().getLLVMFieldNo(FieldD);
1177
1178 int NextStructFieldNo;
1179 if (!NextFieldD) {
1180 NextStructFieldNo = STy->getNumElements();
1181 } else {
1182 NextStructFieldNo = CGM.getTypes().getLLVMFieldNo(NextFieldD);
1183 }
1184
1185 // Append padding
1186 for (int i = StructFieldNo + 1; i < NextStructFieldNo; i++) {
1187 llvm::Constant *C =
1188 llvm::Constant::getNullValue(STy->getElementType(StructFieldNo + 1));
1189
1190 Fields.push_back(C);
1191 }
1192}
1193
1194llvm::Constant *CodeGenModule::
1195GetAddrOfConstantCFString(const StringLiteral *Literal) {
1196 std::string str;
1197 unsigned StringLength = 0;
1198
1199 bool isUTF16 = false;
1200 if (Literal->containsNonAsciiOrNull()) {
1201 // Convert from UTF-8 to UTF-16.
1202 llvm::SmallVector<UTF16, 128> ToBuf(Literal->getByteLength());
1203 const UTF8 *FromPtr = (UTF8 *)Literal->getStrData();
1204 UTF16 *ToPtr = &ToBuf[0];
1205
1206 ConversionResult Result;
1207 Result = ConvertUTF8toUTF16(&FromPtr, FromPtr+Literal->getByteLength(),
1208 &ToPtr, ToPtr+Literal->getByteLength(),
1209 strictConversion);
1210 if (Result == conversionOK) {
1211 // FIXME: Storing UTF-16 in a C string is a hack to test Unicode strings
1212 // without doing more surgery to this routine. Since we aren't explicitly
1213 // checking for endianness here, it's also a bug (when generating code for
1214 // a target that doesn't match the host endianness). Modeling this as an
1215 // i16 array is likely the cleanest solution.
1216 StringLength = ToPtr-&ToBuf[0];
1217 str.assign((char *)&ToBuf[0], StringLength*2);// Twice as many UTF8 chars.
1218 isUTF16 = true;
1219 } else if (Result == sourceIllegal) {
1220 // FIXME: Have Sema::CheckObjCString() validate the UTF-8 string.
1221 str.assign(Literal->getStrData(), Literal->getByteLength());
1222 StringLength = str.length();
1223 } else
1224 assert(Result == conversionOK && "UTF-8 to UTF-16 conversion failed");
1225
1226 } else {
1227 str.assign(Literal->getStrData(), Literal->getByteLength());
1228 StringLength = str.length();
1229 }
1230 llvm::StringMapEntry<llvm::Constant *> &Entry =
1231 CFConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]);
1232
1233 if (llvm::Constant *C = Entry.getValue())
1234 return C;
1235
1236 llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty);
1237 llvm::Constant *Zeros[] = { Zero, Zero };
1238
1239 if (!CFConstantStringClassRef) {
1240 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
1241 Ty = llvm::ArrayType::get(Ty, 0);
1242
1243 // FIXME: This is fairly broken if __CFConstantStringClassReference is
1244 // already defined, in that it will get renamed and the user will most
1245 // likely see an opaque error message. This is a general issue with relying
1246 // on particular names.
1247 llvm::GlobalVariable *GV =
1248 new llvm::GlobalVariable(Ty, false,
1249 llvm::GlobalVariable::ExternalLinkage, 0,
1250 "__CFConstantStringClassReference",
1251 &getModule());
1252
1253 // Decay array -> ptr
1254 CFConstantStringClassRef =
1255 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2);
1256 }
1257
1258 QualType CFTy = getContext().getCFConstantStringType();
1259 RecordDecl *CFRD = CFTy->getAsRecordType()->getDecl();
1260
1261 const llvm::StructType *STy =
1262 cast<llvm::StructType>(getTypes().ConvertType(CFTy));
1263
1264 std::vector<llvm::Constant*> Fields;
1265 RecordDecl::field_iterator Field = CFRD->field_begin();
1266
1267 // Class pointer.
1268 FieldDecl *CurField = *Field++;
1269 FieldDecl *NextField = *Field++;
1270 appendFieldAndPadding(*this, Fields, CurField, NextField,
1271 CFConstantStringClassRef, CFRD, STy);
1272
1273 // Flags.
1274 CurField = NextField;
1275 NextField = *Field++;
1276 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy);
1277 appendFieldAndPadding(*this, Fields, CurField, NextField,
1278 isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0)
1279 : llvm::ConstantInt::get(Ty, 0x07C8),
1280 CFRD, STy);
1281
1282 // String pointer.
1283 CurField = NextField;
1284 NextField = *Field++;
1285 llvm::Constant *C = llvm::ConstantArray::get(str);
1286
1287 const char *Sect, *Prefix;
1288 bool isConstant;
1289 if (isUTF16) {
1290 Prefix = getContext().Target.getUnicodeStringSymbolPrefix();
1291 Sect = getContext().Target.getUnicodeStringSection();
1292 // FIXME: Why does GCC not set constant here?
1293 isConstant = false;
1294 } else {
1295 Prefix = getContext().Target.getStringSymbolPrefix(true);
1296 Sect = getContext().Target.getCFStringDataSection();
1297 // FIXME: -fwritable-strings should probably affect this, but we
1298 // are following gcc here.
1299 isConstant = true;
1300 }
1301 llvm::GlobalVariable *GV =
1302 new llvm::GlobalVariable(C->getType(), isConstant,
1303 llvm::GlobalValue::InternalLinkage,
1304 C, Prefix, &getModule());
1305 if (Sect)
1306 GV->setSection(Sect);
1307 if (isUTF16) {
1308 unsigned Align = getContext().getTypeAlign(getContext().ShortTy)/8;
1309 GV->setAlignment(Align);
1310 }
1311 appendFieldAndPadding(*this, Fields, CurField, NextField,
1312 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2),
1313 CFRD, STy);
1314
1315 // String length.
1316 CurField = NextField;
1317 NextField = 0;
1318 Ty = getTypes().ConvertType(getContext().LongTy);
1319 appendFieldAndPadding(*this, Fields, CurField, NextField,
1320 llvm::ConstantInt::get(Ty, StringLength), CFRD, STy);
1321
1322 // The struct.
1323 C = llvm::ConstantStruct::get(STy, Fields);
1324 GV = new llvm::GlobalVariable(C->getType(), true,
1325 llvm::GlobalVariable::InternalLinkage, C,
1326 getContext().Target.getCFStringSymbolPrefix(),
1327 &getModule());
1328 if (const char *Sect = getContext().Target.getCFStringSection())
1329 GV->setSection(Sect);
1330 Entry.setValue(GV);
1331
1332 return GV;
1333}
1334
1335/// GetStringForStringLiteral - Return the appropriate bytes for a
1336/// string literal, properly padded to match the literal type.
1337std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) {
1338 const char *StrData = E->getStrData();
1339 unsigned Len = E->getByteLength();
1340
1341 const ConstantArrayType *CAT =
1342 getContext().getAsConstantArrayType(E->getType());
1343 assert(CAT && "String isn't pointer or array!");
1344
1345 // Resize the string to the right size.
1346 std::string Str(StrData, StrData+Len);
1347 uint64_t RealLen = CAT->getSize().getZExtValue();
1348
1349 if (E->isWide())
1350 RealLen *= getContext().Target.getWCharWidth()/8;
1351
1352 Str.resize(RealLen, '\0');
1353
1354 return Str;
1355}
1356
1357/// GetAddrOfConstantStringFromLiteral - Return a pointer to a
1358/// constant array for the given string literal.
1359llvm::Constant *
1360CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
1361 // FIXME: This can be more efficient.
1362 return GetAddrOfConstantString(GetStringForStringLiteral(S));
1363}
1364
1365/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
1366/// array for the given ObjCEncodeExpr node.
1367llvm::Constant *
1368CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) {
1369 std::string Str;
1370 getContext().getObjCEncodingForType(E->getEncodedType(), Str);
1371
1372 return GetAddrOfConstantCString(Str);
1373}
1374
1375
1376/// GenerateWritableString -- Creates storage for a string literal.
1377static llvm::Constant *GenerateStringLiteral(const std::string &str,
1378 bool constant,
1379 CodeGenModule &CGM,
1380 const char *GlobalName) {
1381 // Create Constant for this string literal. Don't add a '\0'.
1382 llvm::Constant *C = llvm::ConstantArray::get(str, false);
1383
1384 // Create a global variable for this string
1385 return new llvm::GlobalVariable(C->getType(), constant,
1386 llvm::GlobalValue::InternalLinkage,
1387 C, GlobalName, &CGM.getModule());
1388}
1389
1390/// GetAddrOfConstantString - Returns a pointer to a character array
1391/// containing the literal. This contents are exactly that of the
1392/// given string, i.e. it will not be null terminated automatically;
1393/// see GetAddrOfConstantCString. Note that whether the result is
1394/// actually a pointer to an LLVM constant depends on
1395/// Feature.WriteableStrings.
1396///
1397/// The result has pointer to array type.
1398llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str,
1399 const char *GlobalName) {
1400 bool IsConstant = !Features.WritableStrings;
1401
1402 // Get the default prefix if a name wasn't specified.
1403 if (!GlobalName)
1404 GlobalName = getContext().Target.getStringSymbolPrefix(IsConstant);
1405
1406 // Don't share any string literals if strings aren't constant.
1407 if (!IsConstant)
1408 return GenerateStringLiteral(str, false, *this, GlobalName);
1409
1410 llvm::StringMapEntry<llvm::Constant *> &Entry =
1411 ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]);
1412
1413 if (Entry.getValue())
1414 return Entry.getValue();
1415
1416 // Create a global variable for this.
1417 llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName);
1418 Entry.setValue(C);
1419 return C;
1420}
1421
1422/// GetAddrOfConstantCString - Returns a pointer to a character
1423/// array containing the literal and a terminating '\-'
1424/// character. The result has pointer to array type.
1425llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str,
1426 const char *GlobalName){
1427 return GetAddrOfConstantString(str + '\0', GlobalName);
1428}
1429
1430/// EmitObjCPropertyImplementations - Emit information for synthesized
1431/// properties for an implementation.
1432void CodeGenModule::EmitObjCPropertyImplementations(const
1433 ObjCImplementationDecl *D) {
1434 for (ObjCImplementationDecl::propimpl_iterator
1435 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) {
1436 ObjCPropertyImplDecl *PID = *i;
1437
1438 // Dynamic is just for type-checking.
1439 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) {
1440 ObjCPropertyDecl *PD = PID->getPropertyDecl();
1441
1442 // Determine which methods need to be implemented, some may have
1443 // been overridden. Note that ::isSynthesized is not the method
1444 // we want, that just indicates if the decl came from a
1445 // property. What we want to know is if the method is defined in
1446 // this implementation.
1447 if (!D->getInstanceMethod(PD->getGetterName()))
1448 CodeGenFunction(*this).GenerateObjCGetter(
1449 const_cast<ObjCImplementationDecl *>(D), PID);
1450 if (!PD->isReadOnly() &&
1451 !D->getInstanceMethod(PD->getSetterName()))
1452 CodeGenFunction(*this).GenerateObjCSetter(
1453 const_cast<ObjCImplementationDecl *>(D), PID);
1454 }
1455 }
1456}
1457
1458/// EmitNamespace - Emit all declarations in a namespace.
1459void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) {
1460 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end();
1461 I != E; ++I)
1462 EmitTopLevelDecl(*I);
1463}
1464
1465// EmitLinkageSpec - Emit all declarations in a linkage spec.
1466void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) {
1467 if (LSD->getLanguage() != LinkageSpecDecl::lang_c) {
1468 ErrorUnsupported(LSD, "linkage spec");
1469 return;
1470 }
1471
1472 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end();
1473 I != E; ++I)
1474 EmitTopLevelDecl(*I);
1475}
1476
1477/// EmitTopLevelDecl - Emit code for a single top level declaration.
1478void CodeGenModule::EmitTopLevelDecl(Decl *D) {
1479 // If an error has occurred, stop code generation, but continue
1480 // parsing and semantic analysis (to ensure all warnings and errors
1481 // are emitted).
1482 if (Diags.hasErrorOccurred())
1483 return;
1484
1485 // Ignore dependent declarations.
1486 if (D->getDeclContext() && D->getDeclContext()->isDependentContext())
1487 return;
1488
1489 switch (D->getKind()) {
1490 case Decl::CXXMethod:
1491 case Decl::Function:
1492 // Skip function templates
1493 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate())
1494 return;
1495
1496 // Fall through
1497
1498 case Decl::Var:
1499 EmitGlobal(GlobalDecl(cast<ValueDecl>(D)));
1500 break;
1501
1502 // C++ Decls
1503 case Decl::Namespace:
1504 EmitNamespace(cast<NamespaceDecl>(D));
1505 break;
1506 // No code generation needed.
1507 case Decl::Using:
1508 case Decl::ClassTemplate:
1509 case Decl::FunctionTemplate:
1510 break;
1511 case Decl::CXXConstructor:
1512 EmitCXXConstructors(cast<CXXConstructorDecl>(D));
1513 break;
1514 case Decl::CXXDestructor:
1515 EmitCXXDestructors(cast<CXXDestructorDecl>(D));
1516 break;
1517
1518 case Decl::StaticAssert:
1519 // Nothing to do.
1520 break;
1521
1522 // Objective-C Decls
1523
1524 // Forward declarations, no (immediate) code generation.
1525 case Decl::ObjCClass:
1526 case Decl::ObjCForwardProtocol:
1527 case Decl::ObjCCategory:
1528 case Decl::ObjCInterface:
1529 break;
1530
1531 case Decl::ObjCProtocol:
1532 Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D));
1533 break;
1534
1535 case Decl::ObjCCategoryImpl:
1536 // Categories have properties but don't support synthesize so we
1537 // can ignore them here.
1538 Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D));
1539 break;
1540
1541 case Decl::ObjCImplementation: {
1542 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D);
1543 EmitObjCPropertyImplementations(OMD);
1544 Runtime->GenerateClass(OMD);
1545 break;
1546 }
1547 case Decl::ObjCMethod: {
1548 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D);
1549 // If this is not a prototype, emit the body.
1550 if (OMD->getBody())
1551 CodeGenFunction(*this).GenerateObjCMethod(OMD);
1552 break;
1553 }
1554 case Decl::ObjCCompatibleAlias:
1555 // compatibility-alias is a directive and has no code gen.
1556 break;
1557
1558 case Decl::LinkageSpec:
1559 EmitLinkageSpec(cast<LinkageSpecDecl>(D));
1560 break;
1561
1562 case Decl::FileScopeAsm: {
1563 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D);
1564 std::string AsmString(AD->getAsmString()->getStrData(),
1565 AD->getAsmString()->getByteLength());
1566
1567 const std::string &S = getModule().getModuleInlineAsm();
1568 if (S.empty())
1569 getModule().setModuleInlineAsm(AsmString);
1570 else
1571 getModule().setModuleInlineAsm(S + '\n' + AsmString);
1572 break;
1573 }
1574
1575 default:
1576 // Make sure we handled everything we should, every other kind is a
1577 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind
1578 // function. Need to recode Decl::Kind to do that easily.
1579 assert(isa<TypeDecl>(D) && "Unsupported decl kind");
1580 }
1581}