CGDecl.cpp revision db2cfecf0eb6683be103b8550026817426da2d42 
1//===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===//
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 contains code to emit Decl nodes as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CGDebugInfo.h"
15#include "CodeGenFunction.h"
16#include "CodeGenModule.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/CharUnits.h"
19#include "clang/AST/Decl.h"
20#include "clang/AST/DeclObjC.h"
21#include "clang/Basic/SourceManager.h"
22#include "clang/Basic/TargetInfo.h"
23#include "clang/Frontend/CodeGenOptions.h"
24#include "llvm/GlobalVariable.h"
25#include "llvm/Intrinsics.h"
26#include "llvm/Target/TargetData.h"
27#include "llvm/Type.h"
28using namespace clang;
29using namespace CodeGen;
30
31
32void CodeGenFunction::EmitDecl(const Decl &D) {
33  switch (D.getKind()) {
34  case Decl::TranslationUnit:
35  case Decl::Namespace:
36  case Decl::UnresolvedUsingTypename:
37  case Decl::ClassTemplateSpecialization:
38  case Decl::ClassTemplatePartialSpecialization:
39  case Decl::TemplateTypeParm:
40  case Decl::UnresolvedUsingValue:
41  case Decl::NonTypeTemplateParm:
42  case Decl::CXXMethod:
43  case Decl::CXXConstructor:
44  case Decl::CXXDestructor:
45  case Decl::CXXConversion:
46  case Decl::Field:
47  case Decl::ObjCIvar:
48  case Decl::ObjCAtDefsField:
49  case Decl::ParmVar:
50  case Decl::ImplicitParam:
51  case Decl::ClassTemplate:
52  case Decl::FunctionTemplate:
53  case Decl::TemplateTemplateParm:
54  case Decl::ObjCMethod:
55  case Decl::ObjCCategory:
56  case Decl::ObjCProtocol:
57  case Decl::ObjCInterface:
58  case Decl::ObjCCategoryImpl:
59  case Decl::ObjCImplementation:
60  case Decl::ObjCProperty:
61  case Decl::ObjCCompatibleAlias:
62  case Decl::AccessSpec:
63  case Decl::LinkageSpec:
64  case Decl::ObjCPropertyImpl:
65  case Decl::ObjCClass:
66  case Decl::ObjCForwardProtocol:
67  case Decl::FileScopeAsm:
68  case Decl::Friend:
69  case Decl::FriendTemplate:
70  case Decl::Block:
71
72    assert(0 && "Declaration not should not be in declstmts!");
73  case Decl::Function:  // void X();
74  case Decl::Record:    // struct/union/class X;
75  case Decl::Enum:      // enum X;
76  case Decl::EnumConstant: // enum ? { X = ? }
77  case Decl::CXXRecord: // struct/union/class X; [C++]
78  case Decl::Using:          // using X; [C++]
79  case Decl::UsingShadow:
80  case Decl::UsingDirective: // using namespace X; [C++]
81  case Decl::NamespaceAlias:
82  case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
83    // None of these decls require codegen support.
84    return;
85
86  case Decl::Var: {
87    const VarDecl &VD = cast<VarDecl>(D);
88    assert(VD.isBlockVarDecl() &&
89           "Should not see file-scope variables inside a function!");
90    return EmitBlockVarDecl(VD);
91  }
92
93  case Decl::Typedef: {   // typedef int X;
94    const TypedefDecl &TD = cast<TypedefDecl>(D);
95    QualType Ty = TD.getUnderlyingType();
96
97    if (Ty->isVariablyModifiedType())
98      EmitVLASize(Ty);
99  }
100  }
101}
102
103/// EmitBlockVarDecl - This method handles emission of any variable declaration
104/// inside a function, including static vars etc.
105void CodeGenFunction::EmitBlockVarDecl(const VarDecl &D) {
106  if (D.hasAttr<AsmLabelAttr>())
107    CGM.ErrorUnsupported(&D, "__asm__");
108
109  switch (D.getStorageClass()) {
110  case VarDecl::None:
111  case VarDecl::Auto:
112  case VarDecl::Register:
113    return EmitLocalBlockVarDecl(D);
114  case VarDecl::Static: {
115    llvm::GlobalValue::LinkageTypes Linkage =
116      llvm::GlobalValue::InternalLinkage;
117
118    // If the function definition has some sort of weak linkage, its
119    // static variables should also be weak so that they get properly
120    // uniqued.  We can't do this in C, though, because there's no
121    // standard way to agree on which variables are the same (i.e.
122    // there's no mangling).
123    if (getContext().getLangOptions().CPlusPlus)
124      if (llvm::GlobalValue::isWeakForLinker(CurFn->getLinkage()))
125        Linkage = CurFn->getLinkage();
126
127    return EmitStaticBlockVarDecl(D, Linkage);
128  }
129  case VarDecl::Extern:
130  case VarDecl::PrivateExtern:
131    // Don't emit it now, allow it to be emitted lazily on its first use.
132    return;
133  }
134
135  assert(0 && "Unknown storage class");
136}
137
138static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D,
139                                     const char *Separator) {
140  CodeGenModule &CGM = CGF.CGM;
141  if (CGF.getContext().getLangOptions().CPlusPlus) {
142    llvm::StringRef Name = CGM.getMangledName(&D);
143    return Name.str();
144  }
145
146  std::string ContextName;
147  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl)) {
148    llvm::StringRef Name = CGM.getMangledName(FD);
149    ContextName = Name.str();
150  } else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl))
151    ContextName = CGF.CurFn->getName();
152  else
153    // FIXME: What about in a block??
154    assert(0 && "Unknown context for block var decl");
155
156  return ContextName + Separator + D.getNameAsString();
157}
158
159llvm::GlobalVariable *
160CodeGenFunction::CreateStaticBlockVarDecl(const VarDecl &D,
161                                          const char *Separator,
162                                      llvm::GlobalValue::LinkageTypes Linkage) {
163  QualType Ty = D.getType();
164  assert(Ty->isConstantSizeType() && "VLAs can't be static");
165
166  std::string Name = GetStaticDeclName(*this, D, Separator);
167
168  const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty);
169  llvm::GlobalVariable *GV =
170    new llvm::GlobalVariable(CGM.getModule(), LTy,
171                             Ty.isConstant(getContext()), Linkage,
172                             CGM.EmitNullConstant(D.getType()), Name, 0,
173                             D.isThreadSpecified(), Ty.getAddressSpace());
174  GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
175  return GV;
176}
177
178/// AddInitializerToGlobalBlockVarDecl - Add the initializer for 'D' to the
179/// global variable that has already been created for it.  If the initializer
180/// has a different type than GV does, this may free GV and return a different
181/// one.  Otherwise it just returns GV.
182llvm::GlobalVariable *
183CodeGenFunction::AddInitializerToGlobalBlockVarDecl(const VarDecl &D,
184                                                    llvm::GlobalVariable *GV) {
185  llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(), D.getType(), this);
186
187  // If constant emission failed, then this should be a C++ static
188  // initializer.
189  if (!Init) {
190    if (!getContext().getLangOptions().CPlusPlus)
191      CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
192    else {
193      // Since we have a static initializer, this global variable can't
194      // be constant.
195      GV->setConstant(false);
196
197      EmitStaticCXXBlockVarDeclInit(D, GV);
198    }
199    return GV;
200  }
201
202  // The initializer may differ in type from the global. Rewrite
203  // the global to match the initializer.  (We have to do this
204  // because some types, like unions, can't be completely represented
205  // in the LLVM type system.)
206  if (GV->getType() != Init->getType()) {
207    llvm::GlobalVariable *OldGV = GV;
208
209    GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
210                                  OldGV->isConstant(),
211                                  OldGV->getLinkage(), Init, "",
212                                  0, D.isThreadSpecified(),
213                                  D.getType().getAddressSpace());
214
215    // Steal the name of the old global
216    GV->takeName(OldGV);
217
218    // Replace all uses of the old global with the new global
219    llvm::Constant *NewPtrForOldDecl =
220    llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
221    OldGV->replaceAllUsesWith(NewPtrForOldDecl);
222
223    // Erase the old global, since it is no longer used.
224    OldGV->eraseFromParent();
225  }
226
227  GV->setInitializer(Init);
228  return GV;
229}
230
231void CodeGenFunction::EmitStaticBlockVarDecl(const VarDecl &D,
232                                      llvm::GlobalValue::LinkageTypes Linkage) {
233  llvm::Value *&DMEntry = LocalDeclMap[&D];
234  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
235
236  llvm::GlobalVariable *GV = CreateStaticBlockVarDecl(D, ".", Linkage);
237
238  // Store into LocalDeclMap before generating initializer to handle
239  // circular references.
240  DMEntry = GV;
241
242  // We can't have a VLA here, but we can have a pointer to a VLA,
243  // even though that doesn't really make any sense.
244  // Make sure to evaluate VLA bounds now so that we have them for later.
245  if (D.getType()->isVariablyModifiedType())
246    EmitVLASize(D.getType());
247
248  // If this value has an initializer, emit it.
249  if (D.getInit())
250    GV = AddInitializerToGlobalBlockVarDecl(D, GV);
251
252  GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
253
254  // FIXME: Merge attribute handling.
255  if (const AnnotateAttr *AA = D.getAttr<AnnotateAttr>()) {
256    SourceManager &SM = CGM.getContext().getSourceManager();
257    llvm::Constant *Ann =
258      CGM.EmitAnnotateAttr(GV, AA,
259                           SM.getInstantiationLineNumber(D.getLocation()));
260    CGM.AddAnnotation(Ann);
261  }
262
263  if (const SectionAttr *SA = D.getAttr<SectionAttr>())
264    GV->setSection(SA->getName());
265
266  if (D.hasAttr<UsedAttr>())
267    CGM.AddUsedGlobal(GV);
268
269  if (getContext().getLangOptions().CPlusPlus)
270    CGM.setStaticLocalDeclAddress(&D, GV);
271
272  // We may have to cast the constant because of the initializer
273  // mismatch above.
274  //
275  // FIXME: It is really dangerous to store this in the map; if anyone
276  // RAUW's the GV uses of this constant will be invalid.
277  const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(D.getType());
278  const llvm::Type *LPtrTy =
279    llvm::PointerType::get(LTy, D.getType().getAddressSpace());
280  DMEntry = llvm::ConstantExpr::getBitCast(GV, LPtrTy);
281
282  // Emit global variable debug descriptor for static vars.
283  CGDebugInfo *DI = getDebugInfo();
284  if (DI) {
285    DI->setLocation(D.getLocation());
286    DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(GV), &D);
287  }
288}
289
290unsigned CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const {
291  assert(ByRefValueInfo.count(VD) && "Did not find value!");
292
293  return ByRefValueInfo.find(VD)->second.second;
294}
295
296/// BuildByRefType - This routine changes a __block variable declared as T x
297///   into:
298///
299///      struct {
300///        void *__isa;
301///        void *__forwarding;
302///        int32_t __flags;
303///        int32_t __size;
304///        void *__copy_helper;       // only if needed
305///        void *__destroy_helper;    // only if needed
306///        char padding[X];           // only if needed
307///        T x;
308///      } x
309///
310const llvm::Type *CodeGenFunction::BuildByRefType(const ValueDecl *D) {
311  std::pair<const llvm::Type *, unsigned> &Info = ByRefValueInfo[D];
312  if (Info.first)
313    return Info.first;
314
315  QualType Ty = D->getType();
316
317  std::vector<const llvm::Type *> Types;
318
319  const llvm::PointerType *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
320
321  llvm::PATypeHolder ByRefTypeHolder = llvm::OpaqueType::get(VMContext);
322
323  // void *__isa;
324  Types.push_back(Int8PtrTy);
325
326  // void *__forwarding;
327  Types.push_back(llvm::PointerType::getUnqual(ByRefTypeHolder));
328
329  // int32_t __flags;
330  Types.push_back(Int32Ty);
331
332  // int32_t __size;
333  Types.push_back(Int32Ty);
334
335  bool HasCopyAndDispose = BlockRequiresCopying(Ty);
336  if (HasCopyAndDispose) {
337    /// void *__copy_helper;
338    Types.push_back(Int8PtrTy);
339
340    /// void *__destroy_helper;
341    Types.push_back(Int8PtrTy);
342  }
343
344  bool Packed = false;
345  CharUnits Align = getContext().getDeclAlign(D);
346  if (Align > CharUnits::fromQuantity(Target.getPointerAlign(0) / 8)) {
347    // We have to insert padding.
348
349    // The struct above has 2 32-bit integers.
350    unsigned CurrentOffsetInBytes = 4 * 2;
351
352    // And either 2 or 4 pointers.
353    CurrentOffsetInBytes += (HasCopyAndDispose ? 4 : 2) *
354      CGM.getTargetData().getTypeAllocSize(Int8PtrTy);
355
356    // Align the offset.
357    unsigned AlignedOffsetInBytes =
358      llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align.getQuantity());
359
360    unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes;
361    if (NumPaddingBytes > 0) {
362      const llvm::Type *Ty = llvm::Type::getInt8Ty(VMContext);
363      // FIXME: We need a sema error for alignment larger than the minimum of
364      // the maximal stack alignmint and the alignment of malloc on the system.
365      if (NumPaddingBytes > 1)
366        Ty = llvm::ArrayType::get(Ty, NumPaddingBytes);
367
368      Types.push_back(Ty);
369
370      // We want a packed struct.
371      Packed = true;
372    }
373  }
374
375  // T x;
376  Types.push_back(ConvertType(Ty));
377
378  const llvm::Type *T = llvm::StructType::get(VMContext, Types, Packed);
379
380  cast<llvm::OpaqueType>(ByRefTypeHolder.get())->refineAbstractTypeTo(T);
381  CGM.getModule().addTypeName("struct.__block_byref_" + D->getNameAsString(),
382                              ByRefTypeHolder.get());
383
384  Info.first = ByRefTypeHolder.get();
385
386  Info.second = Types.size() - 1;
387
388  return Info.first;
389}
390
391namespace {
392  struct CallArrayDtor : EHScopeStack::Cleanup {
393    CallArrayDtor(const CXXDestructorDecl *Dtor,
394                  const ConstantArrayType *Type,
395                  llvm::Value *Loc)
396      : Dtor(Dtor), Type(Type), Loc(Loc) {}
397
398    const CXXDestructorDecl *Dtor;
399    const ConstantArrayType *Type;
400    llvm::Value *Loc;
401
402    void Emit(CodeGenFunction &CGF, bool IsForEH) {
403      QualType BaseElementTy = CGF.getContext().getBaseElementType(Type);
404      const llvm::Type *BasePtr = CGF.ConvertType(BaseElementTy);
405      BasePtr = llvm::PointerType::getUnqual(BasePtr);
406      llvm::Value *BaseAddrPtr = CGF.Builder.CreateBitCast(Loc, BasePtr);
407      CGF.EmitCXXAggrDestructorCall(Dtor, Type, BaseAddrPtr);
408    }
409  };
410
411  struct CallVarDtor : EHScopeStack::Cleanup {
412    CallVarDtor(const CXXDestructorDecl *Dtor,
413                llvm::Value *NRVOFlag,
414                llvm::Value *Loc)
415      : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(Loc) {}
416
417    const CXXDestructorDecl *Dtor;
418    llvm::Value *NRVOFlag;
419    llvm::Value *Loc;
420
421    void Emit(CodeGenFunction &CGF, bool IsForEH) {
422      // Along the exceptions path we always execute the dtor.
423      bool NRVO = !IsForEH && NRVOFlag;
424
425      llvm::BasicBlock *SkipDtorBB = 0;
426      if (NRVO) {
427        // If we exited via NRVO, we skip the destructor call.
428        llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused");
429        SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor");
430        llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val");
431        CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB);
432        CGF.EmitBlock(RunDtorBB);
433      }
434
435      CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
436                                /*ForVirtualBase=*/false, Loc);
437
438      if (NRVO) CGF.EmitBlock(SkipDtorBB);
439    }
440  };
441}
442
443namespace {
444  struct CallStackRestore : EHScopeStack::Cleanup {
445    llvm::Value *Stack;
446    CallStackRestore(llvm::Value *Stack) : Stack(Stack) {}
447    void Emit(CodeGenFunction &CGF, bool IsForEH) {
448      llvm::Value *V = CGF.Builder.CreateLoad(Stack, "tmp");
449      llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
450      CGF.Builder.CreateCall(F, V);
451    }
452  };
453
454  struct CallCleanupFunction : EHScopeStack::Cleanup {
455    llvm::Constant *CleanupFn;
456    const CGFunctionInfo &FnInfo;
457    llvm::Value *Addr;
458    const VarDecl &Var;
459
460    CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
461                        llvm::Value *Addr, const VarDecl *Var)
462      : CleanupFn(CleanupFn), FnInfo(*Info), Addr(Addr), Var(*Var) {}
463
464    void Emit(CodeGenFunction &CGF, bool IsForEH) {
465      // In some cases, the type of the function argument will be different from
466      // the type of the pointer. An example of this is
467      // void f(void* arg);
468      // __attribute__((cleanup(f))) void *g;
469      //
470      // To fix this we insert a bitcast here.
471      QualType ArgTy = FnInfo.arg_begin()->type;
472      llvm::Value *Arg =
473        CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy));
474
475      CallArgList Args;
476      Args.push_back(std::make_pair(RValue::get(Arg),
477                            CGF.getContext().getPointerType(Var.getType())));
478      CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args);
479    }
480  };
481
482  struct CallBlockRelease : EHScopeStack::Cleanup {
483    llvm::Value *Addr;
484    CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {}
485
486    void Emit(CodeGenFunction &CGF, bool IsForEH) {
487      llvm::Value *V = CGF.Builder.CreateStructGEP(Addr, 1, "forwarding");
488      V = CGF.Builder.CreateLoad(V);
489      CGF.BuildBlockRelease(V);
490    }
491  };
492}
493
494/// EmitLocalBlockVarDecl - Emit code and set up an entry in LocalDeclMap for a
495/// variable declaration with auto, register, or no storage class specifier.
496/// These turn into simple stack objects, or GlobalValues depending on target.
497void CodeGenFunction::EmitLocalBlockVarDecl(const VarDecl &D,
498                                            SpecialInitFn *SpecialInit) {
499  QualType Ty = D.getType();
500  bool isByRef = D.hasAttr<BlocksAttr>();
501  bool needsDispose = false;
502  CharUnits Align = CharUnits::Zero();
503  bool IsSimpleConstantInitializer = false;
504
505  bool NRVO = false;
506  llvm::Value *NRVOFlag = 0;
507  llvm::Value *DeclPtr;
508  if (Ty->isConstantSizeType()) {
509    if (!Target.useGlobalsForAutomaticVariables()) {
510      NRVO = getContext().getLangOptions().ElideConstructors &&
511             D.isNRVOVariable();
512      // If this value is an array or struct, is POD, and if the initializer is
513      // a staticly determinable constant, try to optimize it (unless the NRVO
514      // is already optimizing this).
515      if (D.getInit() && !isByRef &&
516          (Ty->isArrayType() || Ty->isRecordType()) &&
517          Ty->isPODType() &&
518          D.getInit()->isConstantInitializer(getContext()) && !NRVO) {
519        // If this variable is marked 'const', emit the value as a global.
520        if (CGM.getCodeGenOpts().MergeAllConstants &&
521            Ty.isConstant(getContext())) {
522          EmitStaticBlockVarDecl(D, llvm::GlobalValue::InternalLinkage);
523          return;
524        }
525
526        IsSimpleConstantInitializer = true;
527      }
528
529      // A normal fixed sized variable becomes an alloca in the entry block,
530      // unless it's an NRVO variable.
531      const llvm::Type *LTy = ConvertTypeForMem(Ty);
532
533      if (NRVO) {
534        // The named return value optimization: allocate this variable in the
535        // return slot, so that we can elide the copy when returning this
536        // variable (C++0x [class.copy]p34).
537        DeclPtr = ReturnValue;
538
539        if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
540          if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) {
541            // Create a flag that is used to indicate when the NRVO was applied
542            // to this variable. Set it to zero to indicate that NRVO was not
543            // applied.
544            const llvm::Type *BoolTy = llvm::Type::getInt1Ty(VMContext);
545            llvm::Value *Zero = llvm::ConstantInt::get(BoolTy, 0);
546            NRVOFlag = CreateTempAlloca(BoolTy, "nrvo");
547            Builder.CreateStore(Zero, NRVOFlag);
548
549            // Record the NRVO flag for this variable.
550            NRVOFlags[&D] = NRVOFlag;
551          }
552        }
553      } else {
554        if (isByRef)
555          LTy = BuildByRefType(&D);
556
557        llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
558        Alloc->setName(D.getNameAsString());
559
560        Align = getContext().getDeclAlign(&D);
561        if (isByRef)
562          Align = std::max(Align,
563              CharUnits::fromQuantity(Target.getPointerAlign(0) / 8));
564        Alloc->setAlignment(Align.getQuantity());
565        DeclPtr = Alloc;
566      }
567    } else {
568      // Targets that don't support recursion emit locals as globals.
569      const char *Class =
570        D.getStorageClass() == VarDecl::Register ? ".reg." : ".auto.";
571      DeclPtr = CreateStaticBlockVarDecl(D, Class,
572                                         llvm::GlobalValue
573                                         ::InternalLinkage);
574    }
575
576    // FIXME: Can this happen?
577    if (Ty->isVariablyModifiedType())
578      EmitVLASize(Ty);
579  } else {
580    EnsureInsertPoint();
581
582    if (!DidCallStackSave) {
583      // Save the stack.
584      const llvm::Type *LTy = llvm::Type::getInt8PtrTy(VMContext);
585      llvm::Value *Stack = CreateTempAlloca(LTy, "saved_stack");
586
587      llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
588      llvm::Value *V = Builder.CreateCall(F);
589
590      Builder.CreateStore(V, Stack);
591
592      DidCallStackSave = true;
593
594      // Push a cleanup block and restore the stack there.
595      EHStack.pushCleanup<CallStackRestore>(NormalCleanup, Stack);
596    }
597
598    // Get the element type.
599    const llvm::Type *LElemTy = ConvertTypeForMem(Ty);
600    const llvm::Type *LElemPtrTy =
601      llvm::PointerType::get(LElemTy, D.getType().getAddressSpace());
602
603    llvm::Value *VLASize = EmitVLASize(Ty);
604
605    // Allocate memory for the array.
606    llvm::AllocaInst *VLA =
607      Builder.CreateAlloca(llvm::Type::getInt8Ty(VMContext), VLASize, "vla");
608    VLA->setAlignment(getContext().getDeclAlign(&D).getQuantity());
609
610    DeclPtr = Builder.CreateBitCast(VLA, LElemPtrTy, "tmp");
611  }
612
613  llvm::Value *&DMEntry = LocalDeclMap[&D];
614  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
615  DMEntry = DeclPtr;
616
617  // Emit debug info for local var declaration.
618  if (CGDebugInfo *DI = getDebugInfo()) {
619    assert(HaveInsertPoint() && "Unexpected unreachable point!");
620
621    DI->setLocation(D.getLocation());
622    if (Target.useGlobalsForAutomaticVariables()) {
623      DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(DeclPtr), &D);
624    } else
625      DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
626  }
627
628  // If this local has an initializer, emit it now.
629  const Expr *Init = D.getInit();
630
631  // If we are at an unreachable point, we don't need to emit the initializer
632  // unless it contains a label.
633  if (!HaveInsertPoint()) {
634    if (!ContainsLabel(Init))
635      Init = 0;
636    else
637      EnsureInsertPoint();
638  }
639
640  if (isByRef) {
641    const llvm::PointerType *PtrToInt8Ty = llvm::Type::getInt8PtrTy(VMContext);
642
643    EnsureInsertPoint();
644    llvm::Value *isa_field = Builder.CreateStructGEP(DeclPtr, 0);
645    llvm::Value *forwarding_field = Builder.CreateStructGEP(DeclPtr, 1);
646    llvm::Value *flags_field = Builder.CreateStructGEP(DeclPtr, 2);
647    llvm::Value *size_field = Builder.CreateStructGEP(DeclPtr, 3);
648    llvm::Value *V;
649    int flag = 0;
650    int flags = 0;
651
652    needsDispose = true;
653
654    if (Ty->isBlockPointerType()) {
655      flag |= BLOCK_FIELD_IS_BLOCK;
656      flags |= BLOCK_HAS_COPY_DISPOSE;
657    } else if (BlockRequiresCopying(Ty)) {
658      flag |= BLOCK_FIELD_IS_OBJECT;
659      flags |= BLOCK_HAS_COPY_DISPOSE;
660    }
661
662    // FIXME: Someone double check this.
663    if (Ty.isObjCGCWeak())
664      flag |= BLOCK_FIELD_IS_WEAK;
665
666    int isa = 0;
667    if (flag&BLOCK_FIELD_IS_WEAK)
668      isa = 1;
669    V = llvm::ConstantInt::get(Int32Ty, isa);
670    V = Builder.CreateIntToPtr(V, PtrToInt8Ty, "isa");
671    Builder.CreateStore(V, isa_field);
672
673    Builder.CreateStore(DeclPtr, forwarding_field);
674
675    V = llvm::ConstantInt::get(Int32Ty, flags);
676    Builder.CreateStore(V, flags_field);
677
678    const llvm::Type *V1;
679    V1 = cast<llvm::PointerType>(DeclPtr->getType())->getElementType();
680    V = llvm::ConstantInt::get(Int32Ty,
681                               CGM.GetTargetTypeStoreSize(V1).getQuantity());
682    Builder.CreateStore(V, size_field);
683
684    if (flags & BLOCK_HAS_COPY_DISPOSE) {
685      BlockHasCopyDispose = true;
686      llvm::Value *copy_helper = Builder.CreateStructGEP(DeclPtr, 4);
687      Builder.CreateStore(BuildbyrefCopyHelper(DeclPtr->getType(), flag,
688                                               Align.getQuantity()),
689                          copy_helper);
690
691      llvm::Value *destroy_helper = Builder.CreateStructGEP(DeclPtr, 5);
692      Builder.CreateStore(BuildbyrefDestroyHelper(DeclPtr->getType(), flag,
693                                                  Align.getQuantity()),
694                          destroy_helper);
695    }
696  }
697
698  if (SpecialInit) {
699    SpecialInit(*this, D, DeclPtr);
700  } else if (Init) {
701    llvm::Value *Loc = DeclPtr;
702    if (isByRef)
703      Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
704                                    D.getNameAsString());
705
706    bool isVolatile =
707    getContext().getCanonicalType(D.getType()).isVolatileQualified();
708
709    // If the initializer was a simple constant initializer, we can optimize it
710    // in various ways.
711    if (IsSimpleConstantInitializer) {
712      llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(),D.getType(),this);
713      assert(Init != 0 && "Wasn't a simple constant init?");
714
715      llvm::Value *AlignVal =
716      llvm::ConstantInt::get(Int32Ty, Align.getQuantity());
717      const llvm::Type *IntPtr =
718      llvm::IntegerType::get(VMContext, LLVMPointerWidth);
719      llvm::Value *SizeVal =
720      llvm::ConstantInt::get(IntPtr,
721                             getContext().getTypeSizeInChars(Ty).getQuantity());
722
723      const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext);
724      if (Loc->getType() != BP)
725        Loc = Builder.CreateBitCast(Loc, BP, "tmp");
726
727      llvm::Value *NotVolatile =
728        llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), 0);
729
730      // If the initializer is all zeros, codegen with memset.
731      if (isa<llvm::ConstantAggregateZero>(Init)) {
732        llvm::Value *Zero =
733          llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext), 0);
734        Builder.CreateCall5(CGM.getMemSetFn(Loc->getType(), SizeVal->getType()),
735                            Loc, Zero, SizeVal, AlignVal, NotVolatile);
736      } else {
737        // Otherwise, create a temporary global with the initializer then
738        // memcpy from the global to the alloca.
739        std::string Name = GetStaticDeclName(*this, D, ".");
740        llvm::GlobalVariable *GV =
741        new llvm::GlobalVariable(CGM.getModule(), Init->getType(), true,
742                                 llvm::GlobalValue::InternalLinkage,
743                                 Init, Name, 0, false, 0);
744        GV->setAlignment(Align.getQuantity());
745
746        llvm::Value *SrcPtr = GV;
747        if (SrcPtr->getType() != BP)
748          SrcPtr = Builder.CreateBitCast(SrcPtr, BP, "tmp");
749
750        Builder.CreateCall5(CGM.getMemCpyFn(Loc->getType(), SrcPtr->getType(),
751                                            SizeVal->getType()),
752                            Loc, SrcPtr, SizeVal, AlignVal, NotVolatile);
753      }
754    } else if (Ty->isReferenceType()) {
755      RValue RV = EmitReferenceBindingToExpr(Init, &D);
756      EmitStoreOfScalar(RV.getScalarVal(), Loc, false, Ty);
757    } else if (!hasAggregateLLVMType(Init->getType())) {
758      llvm::Value *V = EmitScalarExpr(Init);
759      EmitStoreOfScalar(V, Loc, isVolatile, D.getType());
760    } else if (Init->getType()->isAnyComplexType()) {
761      EmitComplexExprIntoAddr(Init, Loc, isVolatile);
762    } else {
763      EmitAggExpr(Init, Loc, isVolatile);
764    }
765  }
766
767  // Handle CXX destruction of variables.
768  QualType DtorTy(Ty);
769  while (const ArrayType *Array = getContext().getAsArrayType(DtorTy))
770    DtorTy = getContext().getBaseElementType(Array);
771  if (const RecordType *RT = DtorTy->getAs<RecordType>())
772    if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
773      if (!ClassDecl->hasTrivialDestructor()) {
774        // Note: We suppress the destructor call when the corresponding NRVO
775        // flag has been set.
776        llvm::Value *Loc = DeclPtr;
777        if (isByRef)
778          Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
779                                        D.getNameAsString());
780
781        const CXXDestructorDecl *D = ClassDecl->getDestructor();
782        assert(D && "EmitLocalBlockVarDecl - destructor is nul");
783
784        if (const ConstantArrayType *Array =
785              getContext().getAsConstantArrayType(Ty)) {
786          EHStack.pushCleanup<CallArrayDtor>(NormalAndEHCleanup,
787                                             D, Array, Loc);
788        } else {
789          EHStack.pushCleanup<CallVarDtor>(NormalAndEHCleanup,
790                                           D, NRVOFlag, Loc);
791        }
792      }
793  }
794
795  // Handle the cleanup attribute
796  if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
797    const FunctionDecl *FD = CA->getFunctionDecl();
798
799    llvm::Constant* F = CGM.GetAddrOfFunction(FD);
800    assert(F && "Could not find function!");
801
802    const CGFunctionInfo &Info = CGM.getTypes().getFunctionInfo(FD);
803    EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup,
804                                             F, &Info, DeclPtr, &D);
805  }
806
807  // If this is a block variable, clean it up.
808  // FIXME: this should be an EH cleanup as well.  rdar://problem/8224178
809  if (needsDispose && CGM.getLangOptions().getGCMode() != LangOptions::GCOnly)
810    EHStack.pushCleanup<CallBlockRelease>(NormalCleanup, DeclPtr);
811}
812
813/// Emit an alloca (or GlobalValue depending on target)
814/// for the specified parameter and set up LocalDeclMap.
815void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg) {
816  // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
817  assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
818         "Invalid argument to EmitParmDecl");
819  QualType Ty = D.getType();
820  CanQualType CTy = getContext().getCanonicalType(Ty);
821
822  llvm::Value *DeclPtr;
823  // If this is an aggregate or variable sized value, reuse the input pointer.
824  if (!Ty->isConstantSizeType() ||
825      CodeGenFunction::hasAggregateLLVMType(Ty)) {
826    DeclPtr = Arg;
827  } else {
828    // Otherwise, create a temporary to hold the value.
829    DeclPtr = CreateMemTemp(Ty, D.getName() + ".addr");
830
831    // Store the initial value into the alloca.
832    EmitStoreOfScalar(Arg, DeclPtr, CTy.isVolatileQualified(), Ty);
833  }
834  Arg->setName(D.getName());
835
836  llvm::Value *&DMEntry = LocalDeclMap[&D];
837  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
838  DMEntry = DeclPtr;
839
840  // Emit debug info for param declaration.
841  if (CGDebugInfo *DI = getDebugInfo()) {
842    DI->setLocation(D.getLocation());
843    DI->EmitDeclareOfArgVariable(&D, DeclPtr, Builder);
844  }
845}
846