CodeGenModule.cpp revision cb421fa690da545b58a720abe5f1c49b166dbde7 
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 "TargetInfo.h"
21#include "clang/CodeGen/CodeGenOptions.h"
22#include "clang/AST/ASTContext.h"
23#include "clang/AST/CharUnits.h"
24#include "clang/AST/DeclObjC.h"
25#include "clang/AST/DeclCXX.h"
26#include "clang/AST/RecordLayout.h"
27#include "clang/Basic/Builtins.h"
28#include "clang/Basic/Diagnostic.h"
29#include "clang/Basic/SourceManager.h"
30#include "clang/Basic/TargetInfo.h"
31#include "clang/Basic/ConvertUTF.h"
32#include "llvm/CallingConv.h"
33#include "llvm/Module.h"
34#include "llvm/Intrinsics.h"
35#include "llvm/LLVMContext.h"
36#include "llvm/ADT/Triple.h"
37#include "llvm/Target/TargetData.h"
38#include "llvm/Support/CallSite.h"
39#include "llvm/Support/ErrorHandling.h"
40using namespace clang;
41using namespace CodeGen;
42
43
44CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO,
45                             llvm::Module &M, const llvm::TargetData &TD,
46                             Diagnostic &diags)
47  : BlockModule(C, M, TD, Types, *this), Context(C),
48    Features(C.getLangOptions()), CodeGenOpts(CGO), TheModule(M),
49    TheTargetData(TD), TheTargetCodeGenInfo(0), Diags(diags),
50    Types(C, M, TD, getTargetCodeGenInfo().getABIInfo()),
51    MangleCtx(C, diags), VTables(*this), Runtime(0),
52    CFConstantStringClassRef(0),
53    VMContext(M.getContext()) {
54
55  if (!Features.ObjC1)
56    Runtime = 0;
57  else if (!Features.NeXTRuntime)
58    Runtime = CreateGNUObjCRuntime(*this);
59  else if (Features.ObjCNonFragileABI)
60    Runtime = CreateMacNonFragileABIObjCRuntime(*this);
61  else
62    Runtime = CreateMacObjCRuntime(*this);
63
64  // If debug info generation is enabled, create the CGDebugInfo object.
65  DebugInfo = CodeGenOpts.DebugInfo ? new CGDebugInfo(*this) : 0;
66}
67
68CodeGenModule::~CodeGenModule() {
69  delete Runtime;
70  delete DebugInfo;
71}
72
73void CodeGenModule::createObjCRuntime() {
74  if (!Features.NeXTRuntime)
75    Runtime = CreateGNUObjCRuntime(*this);
76  else if (Features.ObjCNonFragileABI)
77    Runtime = CreateMacNonFragileABIObjCRuntime(*this);
78  else
79    Runtime = CreateMacObjCRuntime(*this);
80}
81
82void CodeGenModule::Release() {
83  EmitDeferred();
84  EmitCXXGlobalInitFunc();
85  EmitCXXGlobalDtorFunc();
86  if (Runtime)
87    if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction())
88      AddGlobalCtor(ObjCInitFunction);
89  EmitCtorList(GlobalCtors, "llvm.global_ctors");
90  EmitCtorList(GlobalDtors, "llvm.global_dtors");
91  EmitAnnotations();
92  EmitLLVMUsed();
93}
94
95bool CodeGenModule::isTargetDarwin() const {
96  return getContext().Target.getTriple().getOS() == llvm::Triple::Darwin;
97}
98
99/// ErrorUnsupported - Print out an error that codegen doesn't support the
100/// specified stmt yet.
101void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type,
102                                     bool OmitOnError) {
103  if (OmitOnError && getDiags().hasErrorOccurred())
104    return;
105  unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error,
106                                               "cannot compile this %0 yet");
107  std::string Msg = Type;
108  getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID)
109    << Msg << S->getSourceRange();
110}
111
112/// ErrorUnsupported - Print out an error that codegen doesn't support the
113/// specified decl yet.
114void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type,
115                                     bool OmitOnError) {
116  if (OmitOnError && getDiags().hasErrorOccurred())
117    return;
118  unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error,
119                                               "cannot compile this %0 yet");
120  std::string Msg = Type;
121  getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
122}
123
124LangOptions::VisibilityMode
125CodeGenModule::getDeclVisibilityMode(const Decl *D) const {
126  if (const VarDecl *VD = dyn_cast<VarDecl>(D))
127    if (VD->getStorageClass() == VarDecl::PrivateExtern)
128      return LangOptions::Hidden;
129
130  if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>()) {
131    switch (attr->getVisibility()) {
132    default: assert(0 && "Unknown visibility!");
133    case VisibilityAttr::DefaultVisibility:
134      return LangOptions::Default;
135    case VisibilityAttr::HiddenVisibility:
136      return LangOptions::Hidden;
137    case VisibilityAttr::ProtectedVisibility:
138      return LangOptions::Protected;
139    }
140  }
141
142  // This decl should have the same visibility as its parent.
143  if (const DeclContext *DC = D->getDeclContext())
144    return getDeclVisibilityMode(cast<Decl>(DC));
145
146  return getLangOptions().getVisibilityMode();
147}
148
149void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
150                                        const Decl *D) const {
151  // Internal definitions always have default visibility.
152  if (GV->hasLocalLinkage()) {
153    GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
154    return;
155  }
156
157  switch (getDeclVisibilityMode(D)) {
158  default: assert(0 && "Unknown visibility!");
159  case LangOptions::Default:
160    return GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
161  case LangOptions::Hidden:
162    return GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
163  case LangOptions::Protected:
164    return GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
165  }
166}
167
168void CodeGenModule::getMangledName(MangleBuffer &Buffer, GlobalDecl GD) {
169  const NamedDecl *ND = cast<NamedDecl>(GD.getDecl());
170
171  if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND))
172    return getMangledCXXCtorName(Buffer, D, GD.getCtorType());
173  if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND))
174    return getMangledCXXDtorName(Buffer, D, GD.getDtorType());
175
176  return getMangledName(Buffer, ND);
177}
178
179/// \brief Retrieves the mangled name for the given declaration.
180///
181/// If the given declaration requires a mangled name, returns an
182/// const char* containing the mangled name.  Otherwise, returns
183/// the unmangled name.
184///
185void CodeGenModule::getMangledName(MangleBuffer &Buffer,
186                                   const NamedDecl *ND) {
187  if (!getMangleContext().shouldMangleDeclName(ND)) {
188    assert(ND->getIdentifier() && "Attempt to mangle unnamed decl.");
189    Buffer.setString(ND->getNameAsCString());
190    return;
191  }
192
193  getMangleContext().mangleName(ND, Buffer.getBuffer());
194}
195
196llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) {
197  return getModule().getNamedValue(Name);
198}
199
200/// AddGlobalCtor - Add a function to the list that will be called before
201/// main() runs.
202void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) {
203  // FIXME: Type coercion of void()* types.
204  GlobalCtors.push_back(std::make_pair(Ctor, Priority));
205}
206
207/// AddGlobalDtor - Add a function to the list that will be called
208/// when the module is unloaded.
209void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) {
210  // FIXME: Type coercion of void()* types.
211  GlobalDtors.push_back(std::make_pair(Dtor, Priority));
212}
213
214void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) {
215  // Ctor function type is void()*.
216  llvm::FunctionType* CtorFTy =
217    llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
218                            std::vector<const llvm::Type*>(),
219                            false);
220  llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy);
221
222  // Get the type of a ctor entry, { i32, void ()* }.
223  llvm::StructType* CtorStructTy =
224    llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext),
225                          llvm::PointerType::getUnqual(CtorFTy), NULL);
226
227  // Construct the constructor and destructor arrays.
228  std::vector<llvm::Constant*> Ctors;
229  for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
230    std::vector<llvm::Constant*> S;
231    S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
232                I->second, false));
233    S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy));
234    Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S));
235  }
236
237  if (!Ctors.empty()) {
238    llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size());
239    new llvm::GlobalVariable(TheModule, AT, false,
240                             llvm::GlobalValue::AppendingLinkage,
241                             llvm::ConstantArray::get(AT, Ctors),
242                             GlobalName);
243  }
244}
245
246void CodeGenModule::EmitAnnotations() {
247  if (Annotations.empty())
248    return;
249
250  // Create a new global variable for the ConstantStruct in the Module.
251  llvm::Constant *Array =
252  llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(),
253                                                Annotations.size()),
254                           Annotations);
255  llvm::GlobalValue *gv =
256  new llvm::GlobalVariable(TheModule, Array->getType(), false,
257                           llvm::GlobalValue::AppendingLinkage, Array,
258                           "llvm.global.annotations");
259  gv->setSection("llvm.metadata");
260}
261
262static CodeGenModule::GVALinkage
263GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
264                      const LangOptions &Features) {
265  CodeGenModule::GVALinkage External = CodeGenModule::GVA_StrongExternal;
266
267  Linkage L = FD->getLinkage();
268  if (L == ExternalLinkage && Context.getLangOptions().CPlusPlus &&
269      FD->getType()->getLinkage() == UniqueExternalLinkage)
270    L = UniqueExternalLinkage;
271
272  switch (L) {
273  case NoLinkage:
274  case InternalLinkage:
275  case UniqueExternalLinkage:
276    return CodeGenModule::GVA_Internal;
277
278  case ExternalLinkage:
279    switch (FD->getTemplateSpecializationKind()) {
280    case TSK_Undeclared:
281    case TSK_ExplicitSpecialization:
282      External = CodeGenModule::GVA_StrongExternal;
283      break;
284
285    case TSK_ExplicitInstantiationDefinition:
286      return CodeGenModule::GVA_ExplicitTemplateInstantiation;
287
288    case TSK_ExplicitInstantiationDeclaration:
289    case TSK_ImplicitInstantiation:
290      External = CodeGenModule::GVA_TemplateInstantiation;
291      break;
292    }
293  }
294
295  if (!FD->isInlined())
296    return External;
297
298  if (!Features.CPlusPlus || FD->hasAttr<GNUInlineAttr>()) {
299    // GNU or C99 inline semantics. Determine whether this symbol should be
300    // externally visible.
301    if (FD->isInlineDefinitionExternallyVisible())
302      return External;
303
304    // C99 inline semantics, where the symbol is not externally visible.
305    return CodeGenModule::GVA_C99Inline;
306  }
307
308  // C++0x [temp.explicit]p9:
309  //   [ Note: The intent is that an inline function that is the subject of
310  //   an explicit instantiation declaration will still be implicitly
311  //   instantiated when used so that the body can be considered for
312  //   inlining, but that no out-of-line copy of the inline function would be
313  //   generated in the translation unit. -- end note ]
314  if (FD->getTemplateSpecializationKind()
315                                       == TSK_ExplicitInstantiationDeclaration)
316    return CodeGenModule::GVA_C99Inline;
317
318  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
319    const CXXRecordDecl *RD = MD->getParent();
320    if (MD->isVirtual() &&
321	CodeGenVTables::isKeyFunctionInAnotherTU(Context, RD))
322      return CodeGenModule::GVA_C99Inline;
323  }
324
325  return CodeGenModule::GVA_CXXInline;
326}
327
328llvm::GlobalValue::LinkageTypes
329CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
330  GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
331
332  if (Linkage == GVA_Internal) {
333    return llvm::Function::InternalLinkage;
334  } else if (D->hasAttr<DLLExportAttr>()) {
335    return llvm::Function::DLLExportLinkage;
336  } else if (D->hasAttr<WeakAttr>()) {
337    return llvm::Function::WeakAnyLinkage;
338  } else if (Linkage == GVA_C99Inline) {
339    // In C99 mode, 'inline' functions are guaranteed to have a strong
340    // definition somewhere else, so we can use available_externally linkage.
341    return llvm::Function::AvailableExternallyLinkage;
342  } else if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) {
343    // In C++, the compiler has to emit a definition in every translation unit
344    // that references the function.  We should use linkonce_odr because
345    // a) if all references in this translation unit are optimized away, we
346    // don't need to codegen it.  b) if the function persists, it needs to be
347    // merged with other definitions. c) C++ has the ODR, so we know the
348    // definition is dependable.
349    return llvm::Function::LinkOnceODRLinkage;
350  } else if (Linkage == GVA_ExplicitTemplateInstantiation) {
351    // An explicit instantiation of a template has weak linkage, since
352    // explicit instantiations can occur in multiple translation units
353    // and must all be equivalent. However, we are not allowed to
354    // throw away these explicit instantiations.
355    return llvm::Function::WeakODRLinkage;
356  } else {
357    assert(Linkage == GVA_StrongExternal);
358    // Otherwise, we have strong external linkage.
359    return llvm::Function::ExternalLinkage;
360  }
361}
362
363
364/// SetFunctionDefinitionAttributes - Set attributes for a global.
365///
366/// FIXME: This is currently only done for aliases and functions, but not for
367/// variables (these details are set in EmitGlobalVarDefinition for variables).
368void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
369                                                    llvm::GlobalValue *GV) {
370  GV->setLinkage(getFunctionLinkage(D));
371  SetCommonAttributes(D, GV);
372}
373
374void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D,
375                                              const CGFunctionInfo &Info,
376                                              llvm::Function *F) {
377  unsigned CallingConv;
378  AttributeListType AttributeList;
379  ConstructAttributeList(Info, D, AttributeList, CallingConv);
380  F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(),
381                                          AttributeList.size()));
382  F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
383}
384
385void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
386                                                           llvm::Function *F) {
387  if (!Features.Exceptions && !Features.ObjCNonFragileABI)
388    F->addFnAttr(llvm::Attribute::NoUnwind);
389
390  if (D->hasAttr<AlwaysInlineAttr>())
391    F->addFnAttr(llvm::Attribute::AlwaysInline);
392
393  if (D->hasAttr<NoInlineAttr>())
394    F->addFnAttr(llvm::Attribute::NoInline);
395
396  if (Features.getStackProtectorMode() == LangOptions::SSPOn)
397    F->addFnAttr(llvm::Attribute::StackProtect);
398  else if (Features.getStackProtectorMode() == LangOptions::SSPReq)
399    F->addFnAttr(llvm::Attribute::StackProtectReq);
400
401  if (const AlignedAttr *AA = D->getAttr<AlignedAttr>()) {
402    unsigned width = Context.Target.getCharWidth();
403    F->setAlignment(AA->getAlignment() / width);
404    while ((AA = AA->getNext<AlignedAttr>()))
405      F->setAlignment(std::max(F->getAlignment(), AA->getAlignment() / width));
406  }
407  // C++ ABI requires 2-byte alignment for member functions.
408  if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
409    F->setAlignment(2);
410}
411
412void CodeGenModule::SetCommonAttributes(const Decl *D,
413                                        llvm::GlobalValue *GV) {
414  setGlobalVisibility(GV, D);
415
416  if (D->hasAttr<UsedAttr>())
417    AddUsedGlobal(GV);
418
419  if (const SectionAttr *SA = D->getAttr<SectionAttr>())
420    GV->setSection(SA->getName());
421
422  getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this);
423}
424
425void CodeGenModule::SetInternalFunctionAttributes(const Decl *D,
426                                                  llvm::Function *F,
427                                                  const CGFunctionInfo &FI) {
428  SetLLVMFunctionAttributes(D, FI, F);
429  SetLLVMFunctionAttributesForDefinition(D, F);
430
431  F->setLinkage(llvm::Function::InternalLinkage);
432
433  SetCommonAttributes(D, F);
434}
435
436void CodeGenModule::SetFunctionAttributes(GlobalDecl GD,
437                                          llvm::Function *F,
438                                          bool IsIncompleteFunction) {
439  const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
440
441  if (!IsIncompleteFunction)
442    SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F);
443
444  // Only a few attributes are set on declarations; these may later be
445  // overridden by a definition.
446
447  if (FD->hasAttr<DLLImportAttr>()) {
448    F->setLinkage(llvm::Function::DLLImportLinkage);
449  } else if (FD->hasAttr<WeakAttr>() ||
450             FD->hasAttr<WeakImportAttr>()) {
451    // "extern_weak" is overloaded in LLVM; we probably should have
452    // separate linkage types for this.
453    F->setLinkage(llvm::Function::ExternalWeakLinkage);
454  } else {
455    F->setLinkage(llvm::Function::ExternalLinkage);
456  }
457
458  if (const SectionAttr *SA = FD->getAttr<SectionAttr>())
459    F->setSection(SA->getName());
460}
461
462void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) {
463  assert(!GV->isDeclaration() &&
464         "Only globals with definition can force usage.");
465  LLVMUsed.push_back(GV);
466}
467
468void CodeGenModule::EmitLLVMUsed() {
469  // Don't create llvm.used if there is no need.
470  if (LLVMUsed.empty())
471    return;
472
473  const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
474
475  // Convert LLVMUsed to what ConstantArray needs.
476  std::vector<llvm::Constant*> UsedArray;
477  UsedArray.resize(LLVMUsed.size());
478  for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) {
479    UsedArray[i] =
480     llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]),
481                                      i8PTy);
482  }
483
484  if (UsedArray.empty())
485    return;
486  llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size());
487
488  llvm::GlobalVariable *GV =
489    new llvm::GlobalVariable(getModule(), ATy, false,
490                             llvm::GlobalValue::AppendingLinkage,
491                             llvm::ConstantArray::get(ATy, UsedArray),
492                             "llvm.used");
493
494  GV->setSection("llvm.metadata");
495}
496
497void CodeGenModule::EmitDeferred() {
498  // Emit code for any potentially referenced deferred decls.  Since a
499  // previously unused static decl may become used during the generation of code
500  // for a static function, iterate until no  changes are made.
501
502  while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) {
503    if (!DeferredVTables.empty()) {
504      const CXXRecordDecl *RD = DeferredVTables.back();
505      DeferredVTables.pop_back();
506      getVTables().GenerateClassData(getVTableLinkage(RD), RD);
507      continue;
508    }
509
510    GlobalDecl D = DeferredDeclsToEmit.back();
511    DeferredDeclsToEmit.pop_back();
512
513    // Look it up to see if it was defined with a stronger definition (e.g. an
514    // extern inline function with a strong function redefinition).  If so,
515    // just ignore the deferred decl.
516    MangleBuffer Name;
517    getMangledName(Name, D);
518    llvm::GlobalValue *CGRef = GetGlobalValue(Name);
519    assert(CGRef && "Deferred decl wasn't referenced?");
520
521    if (!CGRef->isDeclaration())
522      continue;
523
524    // Otherwise, emit the definition and move on to the next one.
525    EmitGlobalDefinition(D);
526  }
527}
528
529/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the
530/// annotation information for a given GlobalValue.  The annotation struct is
531/// {i8 *, i8 *, i8 *, i32}.  The first field is a constant expression, the
532/// GlobalValue being annotated.  The second field is the constant string
533/// created from the AnnotateAttr's annotation.  The third field is a constant
534/// string containing the name of the translation unit.  The fourth field is
535/// the line number in the file of the annotated value declaration.
536///
537/// FIXME: this does not unique the annotation string constants, as llvm-gcc
538///        appears to.
539///
540llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
541                                                const AnnotateAttr *AA,
542                                                unsigned LineNo) {
543  llvm::Module *M = &getModule();
544
545  // get [N x i8] constants for the annotation string, and the filename string
546  // which are the 2nd and 3rd elements of the global annotation structure.
547  const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext);
548  llvm::Constant *anno = llvm::ConstantArray::get(VMContext,
549                                                  AA->getAnnotation(), true);
550  llvm::Constant *unit = llvm::ConstantArray::get(VMContext,
551                                                  M->getModuleIdentifier(),
552                                                  true);
553
554  // Get the two global values corresponding to the ConstantArrays we just
555  // created to hold the bytes of the strings.
556  llvm::GlobalValue *annoGV =
557    new llvm::GlobalVariable(*M, anno->getType(), false,
558                             llvm::GlobalValue::PrivateLinkage, anno,
559                             GV->getName());
560  // translation unit name string, emitted into the llvm.metadata section.
561  llvm::GlobalValue *unitGV =
562    new llvm::GlobalVariable(*M, unit->getType(), false,
563                             llvm::GlobalValue::PrivateLinkage, unit,
564                             ".str");
565
566  // Create the ConstantStruct for the global annotation.
567  llvm::Constant *Fields[4] = {
568    llvm::ConstantExpr::getBitCast(GV, SBP),
569    llvm::ConstantExpr::getBitCast(annoGV, SBP),
570    llvm::ConstantExpr::getBitCast(unitGV, SBP),
571    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo)
572  };
573  return llvm::ConstantStruct::get(VMContext, Fields, 4, false);
574}
575
576bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) {
577  // Never defer when EmitAllDecls is specified or the decl has
578  // attribute used.
579  if (Features.EmitAllDecls || Global->hasAttr<UsedAttr>())
580    return false;
581
582  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
583    // Constructors and destructors should never be deferred.
584    if (FD->hasAttr<ConstructorAttr>() ||
585        FD->hasAttr<DestructorAttr>())
586      return false;
587
588    // The key function for a class must never be deferred.
589    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Global)) {
590      const CXXRecordDecl *RD = MD->getParent();
591      if (MD->isOutOfLine() && RD->isDynamicClass()) {
592        const CXXMethodDecl *KeyFunction = getContext().getKeyFunction(RD);
593        if (KeyFunction &&
594            KeyFunction->getCanonicalDecl() == MD->getCanonicalDecl())
595          return false;
596      }
597    }
598
599    GVALinkage Linkage = GetLinkageForFunction(getContext(), FD, Features);
600
601    // static, static inline, always_inline, and extern inline functions can
602    // always be deferred.  Normal inline functions can be deferred in C99/C++.
603    // Implicit template instantiations can also be deferred in C++.
604    if (Linkage == GVA_Internal || Linkage == GVA_C99Inline ||
605        Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation)
606      return true;
607    return false;
608  }
609
610  const VarDecl *VD = cast<VarDecl>(Global);
611  assert(VD->isFileVarDecl() && "Invalid decl");
612
613  // We never want to defer structs that have non-trivial constructors or
614  // destructors.
615
616  // FIXME: Handle references.
617  if (const RecordType *RT = VD->getType()->getAs<RecordType>()) {
618    if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
619      if (!RD->hasTrivialConstructor() || !RD->hasTrivialDestructor())
620        return false;
621    }
622  }
623
624  // Static data may be deferred, but out-of-line static data members
625  // cannot be.
626  Linkage L = VD->getLinkage();
627  if (L == ExternalLinkage && getContext().getLangOptions().CPlusPlus &&
628      VD->getType()->getLinkage() == UniqueExternalLinkage)
629    L = UniqueExternalLinkage;
630
631  switch (L) {
632  case NoLinkage:
633  case InternalLinkage:
634  case UniqueExternalLinkage:
635    // Initializer has side effects?
636    if (VD->getInit() && VD->getInit()->HasSideEffects(Context))
637      return false;
638    return !(VD->isStaticDataMember() && VD->isOutOfLine());
639
640  case ExternalLinkage:
641    break;
642  }
643
644  return false;
645}
646
647llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
648  const AliasAttr *AA = VD->getAttr<AliasAttr>();
649  assert(AA && "No alias?");
650
651  const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
652
653  // See if there is already something with the target's name in the module.
654  llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee());
655
656  llvm::Constant *Aliasee;
657  if (isa<llvm::FunctionType>(DeclTy))
658    Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl());
659  else
660    Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(),
661                                    llvm::PointerType::getUnqual(DeclTy), 0);
662  if (!Entry) {
663    llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee);
664    F->setLinkage(llvm::Function::ExternalWeakLinkage);
665    WeakRefReferences.insert(F);
666  }
667
668  return Aliasee;
669}
670
671void CodeGenModule::EmitGlobal(GlobalDecl GD) {
672  const ValueDecl *Global = cast<ValueDecl>(GD.getDecl());
673
674  // Weak references don't produce any output by themselves.
675  if (Global->hasAttr<WeakRefAttr>())
676    return;
677
678  // If this is an alias definition (which otherwise looks like a declaration)
679  // emit it now.
680  if (Global->hasAttr<AliasAttr>())
681    return EmitAliasDefinition(GD);
682
683  // Ignore declarations, they will be emitted on their first use.
684  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
685    // Forward declarations are emitted lazily on first use.
686    if (!FD->isThisDeclarationADefinition())
687      return;
688  } else {
689    const VarDecl *VD = cast<VarDecl>(Global);
690    assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
691
692    if (VD->isThisDeclarationADefinition() != VarDecl::Definition)
693      return;
694  }
695
696  // Defer code generation when possible if this is a static definition, inline
697  // function etc.  These we only want to emit if they are used.
698  if (!MayDeferGeneration(Global)) {
699    // Emit the definition if it can't be deferred.
700    EmitGlobalDefinition(GD);
701    return;
702  }
703
704  // If the value has already been used, add it directly to the
705  // DeferredDeclsToEmit list.
706  MangleBuffer MangledName;
707  getMangledName(MangledName, GD);
708  if (GetGlobalValue(MangledName))
709    DeferredDeclsToEmit.push_back(GD);
710  else {
711    // Otherwise, remember that we saw a deferred decl with this name.  The
712    // first use of the mangled name will cause it to move into
713    // DeferredDeclsToEmit.
714    DeferredDecls[MangledName] = GD;
715  }
716}
717
718void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
719  const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
720
721  PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(),
722                                 Context.getSourceManager(),
723                                 "Generating code for declaration");
724
725  if (isa<CXXMethodDecl>(D))
726    getVTables().EmitVTableRelatedData(GD);
727
728  if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
729    return EmitCXXConstructor(CD, GD.getCtorType());
730
731  if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(D))
732    return EmitCXXDestructor(DD, GD.getDtorType());
733
734  if (isa<FunctionDecl>(D))
735    return EmitGlobalFunctionDefinition(GD);
736
737  if (const VarDecl *VD = dyn_cast<VarDecl>(D))
738    return EmitGlobalVarDefinition(VD);
739
740  assert(0 && "Invalid argument to EmitGlobalDefinition()");
741}
742
743/// GetOrCreateLLVMFunction - If the specified mangled name is not in the
744/// module, create and return an llvm Function with the specified type. If there
745/// is something in the module with the specified name, return it potentially
746/// bitcasted to the right type.
747///
748/// If D is non-null, it specifies a decl that correspond to this.  This is used
749/// to set the attributes on the function when it is first created.
750llvm::Constant *
751CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName,
752                                       const llvm::Type *Ty,
753                                       GlobalDecl D) {
754  // Lookup the entry, lazily creating it if necessary.
755  llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
756  if (Entry) {
757    if (WeakRefReferences.count(Entry)) {
758      const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl());
759      if (FD && !FD->hasAttr<WeakAttr>())
760        Entry->setLinkage(llvm::Function::ExternalLinkage);
761
762      WeakRefReferences.erase(Entry);
763    }
764
765    if (Entry->getType()->getElementType() == Ty)
766      return Entry;
767
768    // Make sure the result is of the correct type.
769    const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
770    return llvm::ConstantExpr::getBitCast(Entry, PTy);
771  }
772
773  // This function doesn't have a complete type (for example, the return
774  // type is an incomplete struct). Use a fake type instead, and make
775  // sure not to try to set attributes.
776  bool IsIncompleteFunction = false;
777  if (!isa<llvm::FunctionType>(Ty)) {
778    Ty = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
779                                 std::vector<const llvm::Type*>(), false);
780    IsIncompleteFunction = true;
781  }
782  llvm::Function *F = llvm::Function::Create(cast<llvm::FunctionType>(Ty),
783                                             llvm::Function::ExternalLinkage,
784                                             MangledName, &getModule());
785  assert(F->getName() == MangledName && "name was uniqued!");
786  if (D.getDecl())
787    SetFunctionAttributes(D, F, IsIncompleteFunction);
788
789  // This is the first use or definition of a mangled name.  If there is a
790  // deferred decl with this name, remember that we need to emit it at the end
791  // of the file.
792  llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName);
793  if (DDI != DeferredDecls.end()) {
794    // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
795    // list, and remove it from DeferredDecls (since we don't need it anymore).
796    DeferredDeclsToEmit.push_back(DDI->second);
797    DeferredDecls.erase(DDI);
798  } else if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl())) {
799    // If this the first reference to a C++ inline function in a class, queue up
800    // the deferred function body for emission.  These are not seen as
801    // top-level declarations.
802    if (FD->isThisDeclarationADefinition() && MayDeferGeneration(FD))
803      DeferredDeclsToEmit.push_back(D);
804    // A called constructor which has no definition or declaration need be
805    // synthesized.
806    else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
807      if (CD->isImplicit()) {
808        assert(CD->isUsed() && "Sema doesn't consider constructor as used.");
809        DeferredDeclsToEmit.push_back(D);
810      }
811    } else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) {
812      if (DD->isImplicit()) {
813        assert(DD->isUsed() && "Sema doesn't consider destructor as used.");
814        DeferredDeclsToEmit.push_back(D);
815      }
816    } else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
817      if (MD->isCopyAssignment() && MD->isImplicit()) {
818        assert(MD->isUsed() && "Sema doesn't consider CopyAssignment as used.");
819        DeferredDeclsToEmit.push_back(D);
820      }
821    }
822  }
823
824  return F;
825}
826
827/// GetAddrOfFunction - Return the address of the given function.  If Ty is
828/// non-null, then this function will use the specified type if it has to
829/// create it (this occurs when we see a definition of the function).
830llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD,
831                                                 const llvm::Type *Ty) {
832  // If there was no specific requested type, just convert it now.
833  if (!Ty)
834    Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType());
835  MangleBuffer MangledName;
836  getMangledName(MangledName, GD);
837  return GetOrCreateLLVMFunction(MangledName, Ty, GD);
838}
839
840/// CreateRuntimeFunction - Create a new runtime function with the specified
841/// type and name.
842llvm::Constant *
843CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy,
844                                     llvm::StringRef Name) {
845  return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl());
846}
847
848static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) {
849  if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType())
850    return false;
851  if (Context.getLangOptions().CPlusPlus &&
852      Context.getBaseElementType(D->getType())->getAs<RecordType>()) {
853    // FIXME: We should do something fancier here!
854    return false;
855  }
856  return true;
857}
858
859/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
860/// create and return an llvm GlobalVariable with the specified type.  If there
861/// is something in the module with the specified name, return it potentially
862/// bitcasted to the right type.
863///
864/// If D is non-null, it specifies a decl that correspond to this.  This is used
865/// to set the attributes on the global when it is first created.
866llvm::Constant *
867CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName,
868                                     const llvm::PointerType *Ty,
869                                     const VarDecl *D) {
870  // Lookup the entry, lazily creating it if necessary.
871  llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
872  if (Entry) {
873    if (WeakRefReferences.count(Entry)) {
874      if (D && !D->hasAttr<WeakAttr>())
875        Entry->setLinkage(llvm::Function::ExternalLinkage);
876
877      WeakRefReferences.erase(Entry);
878    }
879
880    if (Entry->getType() == Ty)
881      return Entry;
882
883    // Make sure the result is of the correct type.
884    return llvm::ConstantExpr::getBitCast(Entry, Ty);
885  }
886
887  // This is the first use or definition of a mangled name.  If there is a
888  // deferred decl with this name, remember that we need to emit it at the end
889  // of the file.
890  llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName);
891  if (DDI != DeferredDecls.end()) {
892    // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
893    // list, and remove it from DeferredDecls (since we don't need it anymore).
894    DeferredDeclsToEmit.push_back(DDI->second);
895    DeferredDecls.erase(DDI);
896  }
897
898  llvm::GlobalVariable *GV =
899    new llvm::GlobalVariable(getModule(), Ty->getElementType(), false,
900                             llvm::GlobalValue::ExternalLinkage,
901                             0, MangledName, 0,
902                             false, Ty->getAddressSpace());
903
904  // Handle things which are present even on external declarations.
905  if (D) {
906    // FIXME: This code is overly simple and should be merged with other global
907    // handling.
908    GV->setConstant(DeclIsConstantGlobal(Context, D));
909
910    // FIXME: Merge with other attribute handling code.
911    if (D->getStorageClass() == VarDecl::PrivateExtern)
912      GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
913
914    if (D->hasAttr<WeakAttr>() ||
915        D->hasAttr<WeakImportAttr>())
916      GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
917
918    GV->setThreadLocal(D->isThreadSpecified());
919  }
920
921  return GV;
922}
923
924
925/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
926/// given global variable.  If Ty is non-null and if the global doesn't exist,
927/// then it will be greated with the specified type instead of whatever the
928/// normal requested type would be.
929llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
930                                                  const llvm::Type *Ty) {
931  assert(D->hasGlobalStorage() && "Not a global variable");
932  QualType ASTTy = D->getType();
933  if (Ty == 0)
934    Ty = getTypes().ConvertTypeForMem(ASTTy);
935
936  const llvm::PointerType *PTy =
937    llvm::PointerType::get(Ty, ASTTy.getAddressSpace());
938
939  MangleBuffer MangledName;
940  getMangledName(MangledName, D);
941  return GetOrCreateLLVMGlobal(MangledName, PTy, D);
942}
943
944/// CreateRuntimeVariable - Create a new runtime global variable with the
945/// specified type and name.
946llvm::Constant *
947CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty,
948                                     llvm::StringRef Name) {
949  return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0);
950}
951
952void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
953  assert(!D->getInit() && "Cannot emit definite definitions here!");
954
955  if (MayDeferGeneration(D)) {
956    // If we have not seen a reference to this variable yet, place it
957    // into the deferred declarations table to be emitted if needed
958    // later.
959    MangleBuffer MangledName;
960    getMangledName(MangledName, D);
961    if (!GetGlobalValue(MangledName)) {
962      DeferredDecls[MangledName] = D;
963      return;
964    }
965  }
966
967  // The tentative definition is the only definition.
968  EmitGlobalVarDefinition(D);
969}
970
971llvm::GlobalVariable::LinkageTypes
972CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) {
973  if (RD->isInAnonymousNamespace() || !RD->hasLinkage())
974    return llvm::GlobalVariable::InternalLinkage;
975
976  if (const CXXMethodDecl *KeyFunction
977                                    = RD->getASTContext().getKeyFunction(RD)) {
978    // If this class has a key function, use that to determine the linkage of
979    // the vtable.
980    const FunctionDecl *Def = 0;
981    if (KeyFunction->getBody(Def))
982      KeyFunction = cast<CXXMethodDecl>(Def);
983
984    switch (KeyFunction->getTemplateSpecializationKind()) {
985      case TSK_Undeclared:
986      case TSK_ExplicitSpecialization:
987        if (KeyFunction->isInlined())
988          return llvm::GlobalVariable::WeakODRLinkage;
989
990        return llvm::GlobalVariable::ExternalLinkage;
991
992      case TSK_ImplicitInstantiation:
993      case TSK_ExplicitInstantiationDefinition:
994        return llvm::GlobalVariable::WeakODRLinkage;
995
996      case TSK_ExplicitInstantiationDeclaration:
997        // FIXME: Use available_externally linkage. However, this currently
998        // breaks LLVM's build due to undefined symbols.
999        //      return llvm::GlobalVariable::AvailableExternallyLinkage;
1000        return llvm::GlobalVariable::WeakODRLinkage;
1001    }
1002  }
1003
1004  switch (RD->getTemplateSpecializationKind()) {
1005  case TSK_Undeclared:
1006  case TSK_ExplicitSpecialization:
1007  case TSK_ImplicitInstantiation:
1008  case TSK_ExplicitInstantiationDefinition:
1009    return llvm::GlobalVariable::WeakODRLinkage;
1010
1011  case TSK_ExplicitInstantiationDeclaration:
1012    // FIXME: Use available_externally linkage. However, this currently
1013    // breaks LLVM's build due to undefined symbols.
1014    //   return llvm::GlobalVariable::AvailableExternallyLinkage;
1015    return llvm::GlobalVariable::WeakODRLinkage;
1016  }
1017
1018  // Silence GCC warning.
1019  return llvm::GlobalVariable::WeakODRLinkage;
1020}
1021
1022static CodeGenModule::GVALinkage
1023GetLinkageForVariable(ASTContext &Context, const VarDecl *VD) {
1024  // If this is a static data member, compute the kind of template
1025  // specialization. Otherwise, this variable is not part of a
1026  // template.
1027  TemplateSpecializationKind TSK = TSK_Undeclared;
1028  if (VD->isStaticDataMember())
1029    TSK = VD->getTemplateSpecializationKind();
1030
1031  Linkage L = VD->getLinkage();
1032  if (L == ExternalLinkage && Context.getLangOptions().CPlusPlus &&
1033      VD->getType()->getLinkage() == UniqueExternalLinkage)
1034    L = UniqueExternalLinkage;
1035
1036  switch (L) {
1037  case NoLinkage:
1038  case InternalLinkage:
1039  case UniqueExternalLinkage:
1040    return CodeGenModule::GVA_Internal;
1041
1042  case ExternalLinkage:
1043    switch (TSK) {
1044    case TSK_Undeclared:
1045    case TSK_ExplicitSpecialization:
1046      return CodeGenModule::GVA_StrongExternal;
1047
1048    case TSK_ExplicitInstantiationDeclaration:
1049      llvm_unreachable("Variable should not be instantiated");
1050      // Fall through to treat this like any other instantiation.
1051
1052    case TSK_ExplicitInstantiationDefinition:
1053      return CodeGenModule::GVA_ExplicitTemplateInstantiation;
1054
1055    case TSK_ImplicitInstantiation:
1056      return CodeGenModule::GVA_TemplateInstantiation;
1057    }
1058  }
1059
1060  return CodeGenModule::GVA_StrongExternal;
1061}
1062
1063CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const {
1064    return CharUnits::fromQuantity(
1065      TheTargetData.getTypeStoreSizeInBits(Ty) / Context.getCharWidth());
1066}
1067
1068void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
1069  llvm::Constant *Init = 0;
1070  QualType ASTTy = D->getType();
1071  bool NonConstInit = false;
1072
1073  const Expr *InitExpr = D->getAnyInitializer();
1074
1075  if (!InitExpr) {
1076    // This is a tentative definition; tentative definitions are
1077    // implicitly initialized with { 0 }.
1078    //
1079    // Note that tentative definitions are only emitted at the end of
1080    // a translation unit, so they should never have incomplete
1081    // type. In addition, EmitTentativeDefinition makes sure that we
1082    // never attempt to emit a tentative definition if a real one
1083    // exists. A use may still exists, however, so we still may need
1084    // to do a RAUW.
1085    assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type");
1086    Init = EmitNullConstant(D->getType());
1087  } else {
1088    Init = EmitConstantExpr(InitExpr, D->getType());
1089
1090    if (!Init) {
1091      QualType T = InitExpr->getType();
1092      if (getLangOptions().CPlusPlus) {
1093        EmitCXXGlobalVarDeclInitFunc(D);
1094        Init = EmitNullConstant(T);
1095        NonConstInit = true;
1096      } else {
1097        ErrorUnsupported(D, "static initializer");
1098        Init = llvm::UndefValue::get(getTypes().ConvertType(T));
1099      }
1100    }
1101  }
1102
1103  const llvm::Type* InitType = Init->getType();
1104  llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType);
1105
1106  // Strip off a bitcast if we got one back.
1107  if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) {
1108    assert(CE->getOpcode() == llvm::Instruction::BitCast ||
1109           // all zero index gep.
1110           CE->getOpcode() == llvm::Instruction::GetElementPtr);
1111    Entry = CE->getOperand(0);
1112  }
1113
1114  // Entry is now either a Function or GlobalVariable.
1115  llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry);
1116
1117  // We have a definition after a declaration with the wrong type.
1118  // We must make a new GlobalVariable* and update everything that used OldGV
1119  // (a declaration or tentative definition) with the new GlobalVariable*
1120  // (which will be a definition).
1121  //
1122  // This happens if there is a prototype for a global (e.g.
1123  // "extern int x[];") and then a definition of a different type (e.g.
1124  // "int x[10];"). This also happens when an initializer has a different type
1125  // from the type of the global (this happens with unions).
1126  if (GV == 0 ||
1127      GV->getType()->getElementType() != InitType ||
1128      GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) {
1129
1130    // Move the old entry aside so that we'll create a new one.
1131    Entry->setName(llvm::StringRef());
1132
1133    // Make a new global with the correct type, this is now guaranteed to work.
1134    GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType));
1135
1136    // Replace all uses of the old global with the new global
1137    llvm::Constant *NewPtrForOldDecl =
1138        llvm::ConstantExpr::getBitCast(GV, Entry->getType());
1139    Entry->replaceAllUsesWith(NewPtrForOldDecl);
1140
1141    // Erase the old global, since it is no longer used.
1142    cast<llvm::GlobalValue>(Entry)->eraseFromParent();
1143  }
1144
1145  if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) {
1146    SourceManager &SM = Context.getSourceManager();
1147    AddAnnotation(EmitAnnotateAttr(GV, AA,
1148                              SM.getInstantiationLineNumber(D->getLocation())));
1149  }
1150
1151  GV->setInitializer(Init);
1152
1153  // If it is safe to mark the global 'constant', do so now.
1154  GV->setConstant(false);
1155  if (!NonConstInit && DeclIsConstantGlobal(Context, D))
1156    GV->setConstant(true);
1157
1158  GV->setAlignment(getContext().getDeclAlign(D).getQuantity());
1159
1160  // Set the llvm linkage type as appropriate.
1161  GVALinkage Linkage = GetLinkageForVariable(getContext(), D);
1162  if (Linkage == GVA_Internal)
1163    GV->setLinkage(llvm::Function::InternalLinkage);
1164  else if (D->hasAttr<DLLImportAttr>())
1165    GV->setLinkage(llvm::Function::DLLImportLinkage);
1166  else if (D->hasAttr<DLLExportAttr>())
1167    GV->setLinkage(llvm::Function::DLLExportLinkage);
1168  else if (D->hasAttr<WeakAttr>()) {
1169    if (GV->isConstant())
1170      GV->setLinkage(llvm::GlobalVariable::WeakODRLinkage);
1171    else
1172      GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
1173  } else if (Linkage == GVA_TemplateInstantiation ||
1174             Linkage == GVA_ExplicitTemplateInstantiation)
1175    // FIXME: It seems like we can provide more specific linkage here
1176    // (LinkOnceODR, WeakODR).
1177    GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
1178  else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon &&
1179           !D->hasExternalStorage() && !D->getInit() &&
1180           !D->getAttr<SectionAttr>()) {
1181    GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
1182    // common vars aren't constant even if declared const.
1183    GV->setConstant(false);
1184  } else
1185    GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
1186
1187  SetCommonAttributes(D, GV);
1188
1189  // Emit global variable debug information.
1190  if (CGDebugInfo *DI = getDebugInfo()) {
1191    DI->setLocation(D->getLocation());
1192    DI->EmitGlobalVariable(GV, D);
1193  }
1194}
1195
1196/// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we
1197/// implement a function with no prototype, e.g. "int foo() {}".  If there are
1198/// existing call uses of the old function in the module, this adjusts them to
1199/// call the new function directly.
1200///
1201/// This is not just a cleanup: the always_inline pass requires direct calls to
1202/// functions to be able to inline them.  If there is a bitcast in the way, it
1203/// won't inline them.  Instcombine normally deletes these calls, but it isn't
1204/// run at -O0.
1205static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
1206                                                      llvm::Function *NewFn) {
1207  // If we're redefining a global as a function, don't transform it.
1208  llvm::Function *OldFn = dyn_cast<llvm::Function>(Old);
1209  if (OldFn == 0) return;
1210
1211  const llvm::Type *NewRetTy = NewFn->getReturnType();
1212  llvm::SmallVector<llvm::Value*, 4> ArgList;
1213
1214  for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end();
1215       UI != E; ) {
1216    // TODO: Do invokes ever occur in C code?  If so, we should handle them too.
1217    llvm::Value::use_iterator I = UI++; // Increment before the CI is erased.
1218    llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I);
1219    llvm::CallSite CS(CI);
1220    if (!CI || !CS.isCallee(I)) continue;
1221
1222    // If the return types don't match exactly, and if the call isn't dead, then
1223    // we can't transform this call.
1224    if (CI->getType() != NewRetTy && !CI->use_empty())
1225      continue;
1226
1227    // If the function was passed too few arguments, don't transform.  If extra
1228    // arguments were passed, we silently drop them.  If any of the types
1229    // mismatch, we don't transform.
1230    unsigned ArgNo = 0;
1231    bool DontTransform = false;
1232    for (llvm::Function::arg_iterator AI = NewFn->arg_begin(),
1233         E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) {
1234      if (CS.arg_size() == ArgNo ||
1235          CS.getArgument(ArgNo)->getType() != AI->getType()) {
1236        DontTransform = true;
1237        break;
1238      }
1239    }
1240    if (DontTransform)
1241      continue;
1242
1243    // Okay, we can transform this.  Create the new call instruction and copy
1244    // over the required information.
1245    ArgList.append(CS.arg_begin(), CS.arg_begin() + ArgNo);
1246    llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(),
1247                                                     ArgList.end(), "", CI);
1248    ArgList.clear();
1249    if (!NewCall->getType()->isVoidTy())
1250      NewCall->takeName(CI);
1251    NewCall->setAttributes(CI->getAttributes());
1252    NewCall->setCallingConv(CI->getCallingConv());
1253
1254    // Finally, remove the old call, replacing any uses with the new one.
1255    if (!CI->use_empty())
1256      CI->replaceAllUsesWith(NewCall);
1257
1258    // Copy debug location attached to CI.
1259    if (!CI->getDebugLoc().isUnknown())
1260      NewCall->setDebugLoc(CI->getDebugLoc());
1261    CI->eraseFromParent();
1262  }
1263}
1264
1265
1266void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) {
1267  const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl());
1268  const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD);
1269  getMangleContext().mangleInitDiscriminator();
1270  // Get or create the prototype for the function.
1271  llvm::Constant *Entry = GetAddrOfFunction(GD, Ty);
1272
1273  // Strip off a bitcast if we got one back.
1274  if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) {
1275    assert(CE->getOpcode() == llvm::Instruction::BitCast);
1276    Entry = CE->getOperand(0);
1277  }
1278
1279
1280  if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) {
1281    llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry);
1282
1283    // If the types mismatch then we have to rewrite the definition.
1284    assert(OldFn->isDeclaration() &&
1285           "Shouldn't replace non-declaration");
1286
1287    // F is the Function* for the one with the wrong type, we must make a new
1288    // Function* and update everything that used F (a declaration) with the new
1289    // Function* (which will be a definition).
1290    //
1291    // This happens if there is a prototype for a function
1292    // (e.g. "int f()") and then a definition of a different type
1293    // (e.g. "int f(int x)").  Move the old function aside so that it
1294    // doesn't interfere with GetAddrOfFunction.
1295    OldFn->setName(llvm::StringRef());
1296    llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty));
1297
1298    // If this is an implementation of a function without a prototype, try to
1299    // replace any existing uses of the function (which may be calls) with uses
1300    // of the new function
1301    if (D->getType()->isFunctionNoProtoType()) {
1302      ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn);
1303      OldFn->removeDeadConstantUsers();
1304    }
1305
1306    // Replace uses of F with the Function we will endow with a body.
1307    if (!Entry->use_empty()) {
1308      llvm::Constant *NewPtrForOldDecl =
1309        llvm::ConstantExpr::getBitCast(NewFn, Entry->getType());
1310      Entry->replaceAllUsesWith(NewPtrForOldDecl);
1311    }
1312
1313    // Ok, delete the old function now, which is dead.
1314    OldFn->eraseFromParent();
1315
1316    Entry = NewFn;
1317  }
1318
1319  llvm::Function *Fn = cast<llvm::Function>(Entry);
1320
1321  CodeGenFunction(*this).GenerateCode(D, Fn);
1322
1323  SetFunctionDefinitionAttributes(D, Fn);
1324  SetLLVMFunctionAttributesForDefinition(D, Fn);
1325
1326  if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>())
1327    AddGlobalCtor(Fn, CA->getPriority());
1328  if (const DestructorAttr *DA = D->getAttr<DestructorAttr>())
1329    AddGlobalDtor(Fn, DA->getPriority());
1330}
1331
1332void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) {
1333  const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
1334  const AliasAttr *AA = D->getAttr<AliasAttr>();
1335  assert(AA && "Not an alias?");
1336
1337  MangleBuffer MangledName;
1338  getMangledName(MangledName, GD);
1339
1340  // If there is a definition in the module, then it wins over the alias.
1341  // This is dubious, but allow it to be safe.  Just ignore the alias.
1342  llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
1343  if (Entry && !Entry->isDeclaration())
1344    return;
1345
1346  const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
1347
1348  // Create a reference to the named value.  This ensures that it is emitted
1349  // if a deferred decl.
1350  llvm::Constant *Aliasee;
1351  if (isa<llvm::FunctionType>(DeclTy))
1352    Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl());
1353  else
1354    Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(),
1355                                    llvm::PointerType::getUnqual(DeclTy), 0);
1356
1357  // Create the new alias itself, but don't set a name yet.
1358  llvm::GlobalValue *GA =
1359    new llvm::GlobalAlias(Aliasee->getType(),
1360                          llvm::Function::ExternalLinkage,
1361                          "", Aliasee, &getModule());
1362
1363  if (Entry) {
1364    assert(Entry->isDeclaration());
1365
1366    // If there is a declaration in the module, then we had an extern followed
1367    // by the alias, as in:
1368    //   extern int test6();
1369    //   ...
1370    //   int test6() __attribute__((alias("test7")));
1371    //
1372    // Remove it and replace uses of it with the alias.
1373    GA->takeName(Entry);
1374
1375    Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA,
1376                                                          Entry->getType()));
1377    Entry->eraseFromParent();
1378  } else {
1379    GA->setName(MangledName.getString());
1380  }
1381
1382  // Set attributes which are particular to an alias; this is a
1383  // specialization of the attributes which may be set on a global
1384  // variable/function.
1385  if (D->hasAttr<DLLExportAttr>()) {
1386    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
1387      // The dllexport attribute is ignored for undefined symbols.
1388      if (FD->getBody())
1389        GA->setLinkage(llvm::Function::DLLExportLinkage);
1390    } else {
1391      GA->setLinkage(llvm::Function::DLLExportLinkage);
1392    }
1393  } else if (D->hasAttr<WeakAttr>() ||
1394             D->hasAttr<WeakRefAttr>() ||
1395             D->hasAttr<WeakImportAttr>()) {
1396    GA->setLinkage(llvm::Function::WeakAnyLinkage);
1397  }
1398
1399  SetCommonAttributes(D, GA);
1400}
1401
1402/// getBuiltinLibFunction - Given a builtin id for a function like
1403/// "__builtin_fabsf", return a Function* for "fabsf".
1404llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD,
1405                                                  unsigned BuiltinID) {
1406  assert((Context.BuiltinInfo.isLibFunction(BuiltinID) ||
1407          Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) &&
1408         "isn't a lib fn");
1409
1410  // Get the name, skip over the __builtin_ prefix (if necessary).
1411  const char *Name = Context.BuiltinInfo.GetName(BuiltinID);
1412  if (Context.BuiltinInfo.isLibFunction(BuiltinID))
1413    Name += 10;
1414
1415  const llvm::FunctionType *Ty =
1416    cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType()));
1417
1418  return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD));
1419}
1420
1421llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys,
1422                                            unsigned NumTys) {
1423  return llvm::Intrinsic::getDeclaration(&getModule(),
1424                                         (llvm::Intrinsic::ID)IID, Tys, NumTys);
1425}
1426
1427
1428llvm::Function *CodeGenModule::getMemCpyFn(const llvm::Type *DestType,
1429                                           const llvm::Type *SrcType,
1430                                           const llvm::Type *SizeType) {
1431  const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType };
1432  return getIntrinsic(llvm::Intrinsic::memcpy, ArgTypes, 3);
1433}
1434
1435llvm::Function *CodeGenModule::getMemMoveFn(const llvm::Type *DestType,
1436                                            const llvm::Type *SrcType,
1437                                            const llvm::Type *SizeType) {
1438  const llvm::Type *ArgTypes[3] = {DestType, SrcType, SizeType };
1439  return getIntrinsic(llvm::Intrinsic::memmove, ArgTypes, 3);
1440}
1441
1442llvm::Function *CodeGenModule::getMemSetFn(const llvm::Type *DestType,
1443                                           const llvm::Type *SizeType) {
1444  const llvm::Type *ArgTypes[2] = { DestType, SizeType };
1445  return getIntrinsic(llvm::Intrinsic::memset, ArgTypes, 2);
1446}
1447
1448static llvm::StringMapEntry<llvm::Constant*> &
1449GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map,
1450                         const StringLiteral *Literal,
1451                         bool TargetIsLSB,
1452                         bool &IsUTF16,
1453                         unsigned &StringLength) {
1454  unsigned NumBytes = Literal->getByteLength();
1455
1456  // Check for simple case.
1457  if (!Literal->containsNonAsciiOrNull()) {
1458    StringLength = NumBytes;
1459    return Map.GetOrCreateValue(llvm::StringRef(Literal->getStrData(),
1460                                                StringLength));
1461  }
1462
1463  // Otherwise, convert the UTF8 literals into a byte string.
1464  llvm::SmallVector<UTF16, 128> ToBuf(NumBytes);
1465  const UTF8 *FromPtr = (UTF8 *)Literal->getStrData();
1466  UTF16 *ToPtr = &ToBuf[0];
1467
1468  ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
1469                                               &ToPtr, ToPtr + NumBytes,
1470                                               strictConversion);
1471
1472  // Check for conversion failure.
1473  if (Result != conversionOK) {
1474    // FIXME: Have Sema::CheckObjCString() validate the UTF-8 string and remove
1475    // this duplicate code.
1476    assert(Result == sourceIllegal && "UTF-8 to UTF-16 conversion failed");
1477    StringLength = NumBytes;
1478    return Map.GetOrCreateValue(llvm::StringRef(Literal->getStrData(),
1479                                                StringLength));
1480  }
1481
1482  // ConvertUTF8toUTF16 returns the length in ToPtr.
1483  StringLength = ToPtr - &ToBuf[0];
1484
1485  // Render the UTF-16 string into a byte array and convert to the target byte
1486  // order.
1487  //
1488  // FIXME: This isn't something we should need to do here.
1489  llvm::SmallString<128> AsBytes;
1490  AsBytes.reserve(StringLength * 2);
1491  for (unsigned i = 0; i != StringLength; ++i) {
1492    unsigned short Val = ToBuf[i];
1493    if (TargetIsLSB) {
1494      AsBytes.push_back(Val & 0xFF);
1495      AsBytes.push_back(Val >> 8);
1496    } else {
1497      AsBytes.push_back(Val >> 8);
1498      AsBytes.push_back(Val & 0xFF);
1499    }
1500  }
1501  // Append one extra null character, the second is automatically added by our
1502  // caller.
1503  AsBytes.push_back(0);
1504
1505  IsUTF16 = true;
1506  return Map.GetOrCreateValue(llvm::StringRef(AsBytes.data(), AsBytes.size()));
1507}
1508
1509llvm::Constant *
1510CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
1511  unsigned StringLength = 0;
1512  bool isUTF16 = false;
1513  llvm::StringMapEntry<llvm::Constant*> &Entry =
1514    GetConstantCFStringEntry(CFConstantStringMap, Literal,
1515                             getTargetData().isLittleEndian(),
1516                             isUTF16, StringLength);
1517
1518  if (llvm::Constant *C = Entry.getValue())
1519    return C;
1520
1521  llvm::Constant *Zero =
1522      llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext));
1523  llvm::Constant *Zeros[] = { Zero, Zero };
1524
1525  // If we don't already have it, get __CFConstantStringClassReference.
1526  if (!CFConstantStringClassRef) {
1527    const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
1528    Ty = llvm::ArrayType::get(Ty, 0);
1529    llvm::Constant *GV = CreateRuntimeVariable(Ty,
1530                                           "__CFConstantStringClassReference");
1531    // Decay array -> ptr
1532    CFConstantStringClassRef =
1533      llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2);
1534  }
1535
1536  QualType CFTy = getContext().getCFConstantStringType();
1537
1538  const llvm::StructType *STy =
1539    cast<llvm::StructType>(getTypes().ConvertType(CFTy));
1540
1541  std::vector<llvm::Constant*> Fields(4);
1542
1543  // Class pointer.
1544  Fields[0] = CFConstantStringClassRef;
1545
1546  // Flags.
1547  const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy);
1548  Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) :
1549    llvm::ConstantInt::get(Ty, 0x07C8);
1550
1551  // String pointer.
1552  llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str());
1553
1554  llvm::GlobalValue::LinkageTypes Linkage;
1555  bool isConstant;
1556  if (isUTF16) {
1557    // FIXME: why do utf strings get "_" labels instead of "L" labels?
1558    Linkage = llvm::GlobalValue::InternalLinkage;
1559    // Note: -fwritable-strings doesn't make unicode CFStrings writable, but
1560    // does make plain ascii ones writable.
1561    isConstant = true;
1562  } else {
1563    Linkage = llvm::GlobalValue::PrivateLinkage;
1564    isConstant = !Features.WritableStrings;
1565  }
1566
1567  llvm::GlobalVariable *GV =
1568    new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C,
1569                             ".str");
1570  if (isUTF16) {
1571    CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy);
1572    GV->setAlignment(Align.getQuantity());
1573  }
1574  Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2);
1575
1576  // String length.
1577  Ty = getTypes().ConvertType(getContext().LongTy);
1578  Fields[3] = llvm::ConstantInt::get(Ty, StringLength);
1579
1580  // The struct.
1581  C = llvm::ConstantStruct::get(STy, Fields);
1582  GV = new llvm::GlobalVariable(getModule(), C->getType(), true,
1583                                llvm::GlobalVariable::PrivateLinkage, C,
1584                                "_unnamed_cfstring_");
1585  if (const char *Sect = getContext().Target.getCFStringSection())
1586    GV->setSection(Sect);
1587  Entry.setValue(GV);
1588
1589  return GV;
1590}
1591
1592/// GetStringForStringLiteral - Return the appropriate bytes for a
1593/// string literal, properly padded to match the literal type.
1594std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) {
1595  const char *StrData = E->getStrData();
1596  unsigned Len = E->getByteLength();
1597
1598  const ConstantArrayType *CAT =
1599    getContext().getAsConstantArrayType(E->getType());
1600  assert(CAT && "String isn't pointer or array!");
1601
1602  // Resize the string to the right size.
1603  std::string Str(StrData, StrData+Len);
1604  uint64_t RealLen = CAT->getSize().getZExtValue();
1605
1606  if (E->isWide())
1607    RealLen *= getContext().Target.getWCharWidth()/8;
1608
1609  Str.resize(RealLen, '\0');
1610
1611  return Str;
1612}
1613
1614/// GetAddrOfConstantStringFromLiteral - Return a pointer to a
1615/// constant array for the given string literal.
1616llvm::Constant *
1617CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
1618  // FIXME: This can be more efficient.
1619  // FIXME: We shouldn't need to bitcast the constant in the wide string case.
1620  llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S));
1621  if (S->isWide()) {
1622    llvm::Type *DestTy =
1623        llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType()));
1624    C = llvm::ConstantExpr::getBitCast(C, DestTy);
1625  }
1626  return C;
1627}
1628
1629/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
1630/// array for the given ObjCEncodeExpr node.
1631llvm::Constant *
1632CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) {
1633  std::string Str;
1634  getContext().getObjCEncodingForType(E->getEncodedType(), Str);
1635
1636  return GetAddrOfConstantCString(Str);
1637}
1638
1639
1640/// GenerateWritableString -- Creates storage for a string literal.
1641static llvm::Constant *GenerateStringLiteral(const std::string &str,
1642                                             bool constant,
1643                                             CodeGenModule &CGM,
1644                                             const char *GlobalName) {
1645  // Create Constant for this string literal. Don't add a '\0'.
1646  llvm::Constant *C =
1647      llvm::ConstantArray::get(CGM.getLLVMContext(), str, false);
1648
1649  // Create a global variable for this string
1650  return new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant,
1651                                  llvm::GlobalValue::PrivateLinkage,
1652                                  C, GlobalName);
1653}
1654
1655/// GetAddrOfConstantString - Returns a pointer to a character array
1656/// containing the literal. This contents are exactly that of the
1657/// given string, i.e. it will not be null terminated automatically;
1658/// see GetAddrOfConstantCString. Note that whether the result is
1659/// actually a pointer to an LLVM constant depends on
1660/// Feature.WriteableStrings.
1661///
1662/// The result has pointer to array type.
1663llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str,
1664                                                       const char *GlobalName) {
1665  bool IsConstant = !Features.WritableStrings;
1666
1667  // Get the default prefix if a name wasn't specified.
1668  if (!GlobalName)
1669    GlobalName = ".str";
1670
1671  // Don't share any string literals if strings aren't constant.
1672  if (!IsConstant)
1673    return GenerateStringLiteral(str, false, *this, GlobalName);
1674
1675  llvm::StringMapEntry<llvm::Constant *> &Entry =
1676    ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]);
1677
1678  if (Entry.getValue())
1679    return Entry.getValue();
1680
1681  // Create a global variable for this.
1682  llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName);
1683  Entry.setValue(C);
1684  return C;
1685}
1686
1687/// GetAddrOfConstantCString - Returns a pointer to a character
1688/// array containing the literal and a terminating '\-'
1689/// character. The result has pointer to array type.
1690llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str,
1691                                                        const char *GlobalName){
1692  return GetAddrOfConstantString(str + '\0', GlobalName);
1693}
1694
1695/// EmitObjCPropertyImplementations - Emit information for synthesized
1696/// properties for an implementation.
1697void CodeGenModule::EmitObjCPropertyImplementations(const
1698                                                    ObjCImplementationDecl *D) {
1699  for (ObjCImplementationDecl::propimpl_iterator
1700         i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) {
1701    ObjCPropertyImplDecl *PID = *i;
1702
1703    // Dynamic is just for type-checking.
1704    if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) {
1705      ObjCPropertyDecl *PD = PID->getPropertyDecl();
1706
1707      // Determine which methods need to be implemented, some may have
1708      // been overridden. Note that ::isSynthesized is not the method
1709      // we want, that just indicates if the decl came from a
1710      // property. What we want to know is if the method is defined in
1711      // this implementation.
1712      if (!D->getInstanceMethod(PD->getGetterName()))
1713        CodeGenFunction(*this).GenerateObjCGetter(
1714                                 const_cast<ObjCImplementationDecl *>(D), PID);
1715      if (!PD->isReadOnly() &&
1716          !D->getInstanceMethod(PD->getSetterName()))
1717        CodeGenFunction(*this).GenerateObjCSetter(
1718                                 const_cast<ObjCImplementationDecl *>(D), PID);
1719    }
1720  }
1721}
1722
1723/// EmitNamespace - Emit all declarations in a namespace.
1724void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) {
1725  for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end();
1726       I != E; ++I)
1727    EmitTopLevelDecl(*I);
1728}
1729
1730// EmitLinkageSpec - Emit all declarations in a linkage spec.
1731void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) {
1732  if (LSD->getLanguage() != LinkageSpecDecl::lang_c &&
1733      LSD->getLanguage() != LinkageSpecDecl::lang_cxx) {
1734    ErrorUnsupported(LSD, "linkage spec");
1735    return;
1736  }
1737
1738  for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end();
1739       I != E; ++I)
1740    EmitTopLevelDecl(*I);
1741}
1742
1743/// EmitTopLevelDecl - Emit code for a single top level declaration.
1744void CodeGenModule::EmitTopLevelDecl(Decl *D) {
1745  // If an error has occurred, stop code generation, but continue
1746  // parsing and semantic analysis (to ensure all warnings and errors
1747  // are emitted).
1748  if (Diags.hasErrorOccurred())
1749    return;
1750
1751  // Ignore dependent declarations.
1752  if (D->getDeclContext() && D->getDeclContext()->isDependentContext())
1753    return;
1754
1755  switch (D->getKind()) {
1756  case Decl::CXXConversion:
1757  case Decl::CXXMethod:
1758  case Decl::Function:
1759    // Skip function templates
1760    if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate())
1761      return;
1762
1763    EmitGlobal(cast<FunctionDecl>(D));
1764    break;
1765
1766  case Decl::Var:
1767    EmitGlobal(cast<VarDecl>(D));
1768    break;
1769
1770  // C++ Decls
1771  case Decl::Namespace:
1772    EmitNamespace(cast<NamespaceDecl>(D));
1773    break;
1774    // No code generation needed.
1775  case Decl::UsingShadow:
1776  case Decl::Using:
1777  case Decl::UsingDirective:
1778  case Decl::ClassTemplate:
1779  case Decl::FunctionTemplate:
1780  case Decl::NamespaceAlias:
1781    break;
1782  case Decl::CXXConstructor:
1783    // Skip function templates
1784    if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate())
1785      return;
1786
1787    EmitCXXConstructors(cast<CXXConstructorDecl>(D));
1788    break;
1789  case Decl::CXXDestructor:
1790    EmitCXXDestructors(cast<CXXDestructorDecl>(D));
1791    break;
1792
1793  case Decl::StaticAssert:
1794    // Nothing to do.
1795    break;
1796
1797  // Objective-C Decls
1798
1799  // Forward declarations, no (immediate) code generation.
1800  case Decl::ObjCClass:
1801  case Decl::ObjCForwardProtocol:
1802  case Decl::ObjCCategory:
1803  case Decl::ObjCInterface:
1804    break;
1805
1806  case Decl::ObjCProtocol:
1807    Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D));
1808    break;
1809
1810  case Decl::ObjCCategoryImpl:
1811    // Categories have properties but don't support synthesize so we
1812    // can ignore them here.
1813    Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D));
1814    break;
1815
1816  case Decl::ObjCImplementation: {
1817    ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D);
1818    EmitObjCPropertyImplementations(OMD);
1819    Runtime->GenerateClass(OMD);
1820    break;
1821  }
1822  case Decl::ObjCMethod: {
1823    ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D);
1824    // If this is not a prototype, emit the body.
1825    if (OMD->getBody())
1826      CodeGenFunction(*this).GenerateObjCMethod(OMD);
1827    break;
1828  }
1829  case Decl::ObjCCompatibleAlias:
1830    // compatibility-alias is a directive and has no code gen.
1831    break;
1832
1833  case Decl::LinkageSpec:
1834    EmitLinkageSpec(cast<LinkageSpecDecl>(D));
1835    break;
1836
1837  case Decl::FileScopeAsm: {
1838    FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D);
1839    llvm::StringRef AsmString = AD->getAsmString()->getString();
1840
1841    const std::string &S = getModule().getModuleInlineAsm();
1842    if (S.empty())
1843      getModule().setModuleInlineAsm(AsmString);
1844    else
1845      getModule().setModuleInlineAsm(S + '\n' + AsmString.str());
1846    break;
1847  }
1848
1849  default:
1850    // Make sure we handled everything we should, every other kind is a
1851    // non-top-level decl.  FIXME: Would be nice to have an isTopLevelDeclKind
1852    // function. Need to recode Decl::Kind to do that easily.
1853    assert(isa<TypeDecl>(D) && "Unsupported decl kind");
1854  }
1855}
1856