CGDecl.cpp revision 201361 
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/CodeGen/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  default:
35    CGM.ErrorUnsupported(&D, "decl");
36    return;
37  case Decl::ParmVar:
38    assert(0 && "Parmdecls should not be in declstmts!");
39  case Decl::Function:  // void X();
40  case Decl::Record:    // struct/union/class X;
41  case Decl::Enum:      // enum X;
42  case Decl::EnumConstant: // enum ? { X = ? }
43  case Decl::CXXRecord: // struct/union/class X; [C++]
44  case Decl::Using:          // using X; [C++]
45  case Decl::UsingShadow:
46  case Decl::UsingDirective: // using namespace X; [C++]
47  case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
48    // None of these decls require codegen support.
49    return;
50
51  case Decl::Var: {
52    const VarDecl &VD = cast<VarDecl>(D);
53    assert(VD.isBlockVarDecl() &&
54           "Should not see file-scope variables inside a function!");
55    return EmitBlockVarDecl(VD);
56  }
57
58  case Decl::Typedef: {   // typedef int X;
59    const TypedefDecl &TD = cast<TypedefDecl>(D);
60    QualType Ty = TD.getUnderlyingType();
61
62    if (Ty->isVariablyModifiedType())
63      EmitVLASize(Ty);
64  }
65  }
66}
67
68/// EmitBlockVarDecl - This method handles emission of any variable declaration
69/// inside a function, including static vars etc.
70void CodeGenFunction::EmitBlockVarDecl(const VarDecl &D) {
71  if (D.hasAttr<AsmLabelAttr>())
72    CGM.ErrorUnsupported(&D, "__asm__");
73
74  switch (D.getStorageClass()) {
75  case VarDecl::None:
76  case VarDecl::Auto:
77  case VarDecl::Register:
78    return EmitLocalBlockVarDecl(D);
79  case VarDecl::Static:
80    return EmitStaticBlockVarDecl(D);
81  case VarDecl::Extern:
82  case VarDecl::PrivateExtern:
83    // Don't emit it now, allow it to be emitted lazily on its first use.
84    return;
85  }
86
87  assert(0 && "Unknown storage class");
88}
89
90static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D,
91                                     const char *Separator) {
92  CodeGenModule &CGM = CGF.CGM;
93  if (CGF.getContext().getLangOptions().CPlusPlus)
94    return CGM.getMangledName(&D);
95
96  std::string ContextName;
97  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl))
98    ContextName = CGM.getMangledName(FD);
99  else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl))
100    ContextName = CGF.CurFn->getName();
101  else
102    // FIXME: What about in a block??
103    assert(0 && "Unknown context for block var decl");
104
105  return ContextName + Separator + D.getNameAsString();
106}
107
108llvm::GlobalVariable *
109CodeGenFunction::CreateStaticBlockVarDecl(const VarDecl &D,
110                                          const char *Separator,
111                                      llvm::GlobalValue::LinkageTypes Linkage) {
112  QualType Ty = D.getType();
113  assert(Ty->isConstantSizeType() && "VLAs can't be static");
114
115  std::string Name = GetStaticDeclName(*this, D, Separator);
116
117  const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty);
118  llvm::GlobalVariable *GV =
119    new llvm::GlobalVariable(CGM.getModule(), LTy,
120                             Ty.isConstant(getContext()), Linkage,
121                             CGM.EmitNullConstant(D.getType()), Name, 0,
122                             D.isThreadSpecified(), Ty.getAddressSpace());
123  GV->setAlignment(getContext().getDeclAlignInBytes(&D));
124  return GV;
125}
126
127/// AddInitializerToGlobalBlockVarDecl - Add the initializer for 'D' to the
128/// global variable that has already been created for it.  If the initializer
129/// has a different type than GV does, this may free GV and return a different
130/// one.  Otherwise it just returns GV.
131llvm::GlobalVariable *
132CodeGenFunction::AddInitializerToGlobalBlockVarDecl(const VarDecl &D,
133                                                    llvm::GlobalVariable *GV) {
134  llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(), D.getType(), this);
135
136  // If constant emission failed, then this should be a C++ static
137  // initializer.
138  if (!Init) {
139    if (!getContext().getLangOptions().CPlusPlus)
140      CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
141    else
142      EmitStaticCXXBlockVarDeclInit(D, GV);
143    return GV;
144  }
145
146  // The initializer may differ in type from the global. Rewrite
147  // the global to match the initializer.  (We have to do this
148  // because some types, like unions, can't be completely represented
149  // in the LLVM type system.)
150  if (GV->getType() != Init->getType()) {
151    llvm::GlobalVariable *OldGV = GV;
152
153    GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
154                                  OldGV->isConstant(),
155                                  OldGV->getLinkage(), Init, "",
156                                  0, D.isThreadSpecified(),
157                                  D.getType().getAddressSpace());
158
159    // Steal the name of the old global
160    GV->takeName(OldGV);
161
162    // Replace all uses of the old global with the new global
163    llvm::Constant *NewPtrForOldDecl =
164    llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
165    OldGV->replaceAllUsesWith(NewPtrForOldDecl);
166
167    // Erase the old global, since it is no longer used.
168    OldGV->eraseFromParent();
169  }
170
171  GV->setInitializer(Init);
172  return GV;
173}
174
175void CodeGenFunction::EmitStaticBlockVarDecl(const VarDecl &D) {
176  llvm::Value *&DMEntry = LocalDeclMap[&D];
177  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
178
179  llvm::GlobalVariable *GV =
180    CreateStaticBlockVarDecl(D, ".", llvm::GlobalValue::InternalLinkage);
181
182  // Store into LocalDeclMap before generating initializer to handle
183  // circular references.
184  DMEntry = GV;
185
186  // Make sure to evaluate VLA bounds now so that we have them for later.
187  //
188  // FIXME: Can this happen?
189  if (D.getType()->isVariablyModifiedType())
190    EmitVLASize(D.getType());
191
192  // If this value has an initializer, emit it.
193  if (D.getInit())
194    GV = AddInitializerToGlobalBlockVarDecl(D, GV);
195
196  // FIXME: Merge attribute handling.
197  if (const AnnotateAttr *AA = D.getAttr<AnnotateAttr>()) {
198    SourceManager &SM = CGM.getContext().getSourceManager();
199    llvm::Constant *Ann =
200      CGM.EmitAnnotateAttr(GV, AA,
201                           SM.getInstantiationLineNumber(D.getLocation()));
202    CGM.AddAnnotation(Ann);
203  }
204
205  if (const SectionAttr *SA = D.getAttr<SectionAttr>())
206    GV->setSection(SA->getName());
207
208  if (D.hasAttr<UsedAttr>())
209    CGM.AddUsedGlobal(GV);
210
211  // We may have to cast the constant because of the initializer
212  // mismatch above.
213  //
214  // FIXME: It is really dangerous to store this in the map; if anyone
215  // RAUW's the GV uses of this constant will be invalid.
216  const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(D.getType());
217  const llvm::Type *LPtrTy =
218    llvm::PointerType::get(LTy, D.getType().getAddressSpace());
219  DMEntry = llvm::ConstantExpr::getBitCast(GV, LPtrTy);
220
221  // Emit global variable debug descriptor for static vars.
222  CGDebugInfo *DI = getDebugInfo();
223  if (DI) {
224    DI->setLocation(D.getLocation());
225    DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(GV), &D);
226  }
227}
228
229unsigned CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const {
230  assert(ByRefValueInfo.count(VD) && "Did not find value!");
231
232  return ByRefValueInfo.find(VD)->second.second;
233}
234
235/// BuildByRefType - This routine changes a __block variable declared as T x
236///   into:
237///
238///      struct {
239///        void *__isa;
240///        void *__forwarding;
241///        int32_t __flags;
242///        int32_t __size;
243///        void *__copy_helper;       // only if needed
244///        void *__destroy_helper;    // only if needed
245///        char padding[X];           // only if needed
246///        T x;
247///      } x
248///
249const llvm::Type *CodeGenFunction::BuildByRefType(const ValueDecl *D) {
250  std::pair<const llvm::Type *, unsigned> &Info = ByRefValueInfo[D];
251  if (Info.first)
252    return Info.first;
253
254  QualType Ty = D->getType();
255
256  std::vector<const llvm::Type *> Types;
257
258  const llvm::PointerType *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
259
260  llvm::PATypeHolder ByRefTypeHolder = llvm::OpaqueType::get(VMContext);
261
262  // void *__isa;
263  Types.push_back(Int8PtrTy);
264
265  // void *__forwarding;
266  Types.push_back(llvm::PointerType::getUnqual(ByRefTypeHolder));
267
268  // int32_t __flags;
269  Types.push_back(llvm::Type::getInt32Ty(VMContext));
270
271  // int32_t __size;
272  Types.push_back(llvm::Type::getInt32Ty(VMContext));
273
274  bool HasCopyAndDispose = BlockRequiresCopying(Ty);
275  if (HasCopyAndDispose) {
276    /// void *__copy_helper;
277    Types.push_back(Int8PtrTy);
278
279    /// void *__destroy_helper;
280    Types.push_back(Int8PtrTy);
281  }
282
283  bool Packed = false;
284  unsigned Align = getContext().getDeclAlignInBytes(D);
285  if (Align > Target.getPointerAlign(0) / 8) {
286    // We have to insert padding.
287
288    // The struct above has 2 32-bit integers.
289    unsigned CurrentOffsetInBytes = 4 * 2;
290
291    // And either 2 or 4 pointers.
292    CurrentOffsetInBytes += (HasCopyAndDispose ? 4 : 2) *
293      CGM.getTargetData().getTypeAllocSize(Int8PtrTy);
294
295    // Align the offset.
296    unsigned AlignedOffsetInBytes =
297      llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align);
298
299    unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes;
300    if (NumPaddingBytes > 0) {
301      const llvm::Type *Ty = llvm::Type::getInt8Ty(VMContext);
302      // FIXME: We need a sema error for alignment larger than the minimum of
303      // the maximal stack alignmint and the alignment of malloc on the system.
304      if (NumPaddingBytes > 1)
305        Ty = llvm::ArrayType::get(Ty, NumPaddingBytes);
306
307      Types.push_back(Ty);
308
309      // We want a packed struct.
310      Packed = true;
311    }
312  }
313
314  // T x;
315  Types.push_back(ConvertType(Ty));
316
317  const llvm::Type *T = llvm::StructType::get(VMContext, Types, Packed);
318
319  cast<llvm::OpaqueType>(ByRefTypeHolder.get())->refineAbstractTypeTo(T);
320  CGM.getModule().addTypeName("struct.__block_byref_" + D->getNameAsString(),
321                              ByRefTypeHolder.get());
322
323  Info.first = ByRefTypeHolder.get();
324
325  Info.second = Types.size() - 1;
326
327  return Info.first;
328}
329
330/// EmitLocalBlockVarDecl - Emit code and set up an entry in LocalDeclMap for a
331/// variable declaration with auto, register, or no storage class specifier.
332/// These turn into simple stack objects, or GlobalValues depending on target.
333void CodeGenFunction::EmitLocalBlockVarDecl(const VarDecl &D) {
334  QualType Ty = D.getType();
335  bool isByRef = D.hasAttr<BlocksAttr>();
336  bool needsDispose = false;
337  unsigned Align = 0;
338  bool IsSimpleConstantInitializer = false;
339
340  llvm::Value *DeclPtr;
341  if (Ty->isConstantSizeType()) {
342    if (!Target.useGlobalsForAutomaticVariables()) {
343
344      // If this value is an array or struct, is POD, and if the initializer is
345      // a staticly determinable constant, try to optimize it.
346      if (D.getInit() && !isByRef &&
347          (Ty->isArrayType() || Ty->isRecordType()) &&
348          Ty->isPODType() &&
349          D.getInit()->isConstantInitializer(getContext())) {
350        // If this variable is marked 'const', emit the value as a global.
351        if (CGM.getCodeGenOpts().MergeAllConstants &&
352            Ty.isConstant(getContext())) {
353          EmitStaticBlockVarDecl(D);
354          return;
355        }
356
357        IsSimpleConstantInitializer = true;
358      }
359
360      // A normal fixed sized variable becomes an alloca in the entry block.
361      const llvm::Type *LTy = ConvertTypeForMem(Ty);
362      if (isByRef)
363        LTy = BuildByRefType(&D);
364      llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
365      Alloc->setName(D.getNameAsString());
366
367      Align = getContext().getDeclAlignInBytes(&D);
368      if (isByRef)
369        Align = std::max(Align, unsigned(Target.getPointerAlign(0) / 8));
370      Alloc->setAlignment(Align);
371      DeclPtr = Alloc;
372    } else {
373      // Targets that don't support recursion emit locals as globals.
374      const char *Class =
375        D.getStorageClass() == VarDecl::Register ? ".reg." : ".auto.";
376      DeclPtr = CreateStaticBlockVarDecl(D, Class,
377                                         llvm::GlobalValue
378                                         ::InternalLinkage);
379    }
380
381    // FIXME: Can this happen?
382    if (Ty->isVariablyModifiedType())
383      EmitVLASize(Ty);
384  } else {
385    EnsureInsertPoint();
386
387    if (!DidCallStackSave) {
388      // Save the stack.
389      const llvm::Type *LTy = llvm::Type::getInt8PtrTy(VMContext);
390      llvm::Value *Stack = CreateTempAlloca(LTy, "saved_stack");
391
392      llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
393      llvm::Value *V = Builder.CreateCall(F);
394
395      Builder.CreateStore(V, Stack);
396
397      DidCallStackSave = true;
398
399      {
400        // Push a cleanup block and restore the stack there.
401        DelayedCleanupBlock scope(*this);
402
403        V = Builder.CreateLoad(Stack, "tmp");
404        llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
405        Builder.CreateCall(F, V);
406      }
407    }
408
409    // Get the element type.
410    const llvm::Type *LElemTy = ConvertTypeForMem(Ty);
411    const llvm::Type *LElemPtrTy =
412      llvm::PointerType::get(LElemTy, D.getType().getAddressSpace());
413
414    llvm::Value *VLASize = EmitVLASize(Ty);
415
416    // Downcast the VLA size expression
417    VLASize = Builder.CreateIntCast(VLASize, llvm::Type::getInt32Ty(VMContext),
418                                    false, "tmp");
419
420    // Allocate memory for the array.
421    llvm::AllocaInst *VLA =
422      Builder.CreateAlloca(llvm::Type::getInt8Ty(VMContext), VLASize, "vla");
423    VLA->setAlignment(getContext().getDeclAlignInBytes(&D));
424
425    DeclPtr = Builder.CreateBitCast(VLA, LElemPtrTy, "tmp");
426  }
427
428  llvm::Value *&DMEntry = LocalDeclMap[&D];
429  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
430  DMEntry = DeclPtr;
431
432  // Emit debug info for local var declaration.
433  if (CGDebugInfo *DI = getDebugInfo()) {
434    assert(HaveInsertPoint() && "Unexpected unreachable point!");
435
436    DI->setLocation(D.getLocation());
437    if (Target.useGlobalsForAutomaticVariables()) {
438      DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(DeclPtr), &D);
439    } else
440      DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
441  }
442
443  // If this local has an initializer, emit it now.
444  const Expr *Init = D.getInit();
445
446  // If we are at an unreachable point, we don't need to emit the initializer
447  // unless it contains a label.
448  if (!HaveInsertPoint()) {
449    if (!ContainsLabel(Init))
450      Init = 0;
451    else
452      EnsureInsertPoint();
453  }
454
455  if (Init) {
456    llvm::Value *Loc = DeclPtr;
457    if (isByRef)
458      Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
459                                    D.getNameAsString());
460
461    bool isVolatile =
462      getContext().getCanonicalType(D.getType()).isVolatileQualified();
463
464    // If the initializer was a simple constant initializer, we can optimize it
465    // in various ways.
466    if (IsSimpleConstantInitializer) {
467      llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(),D.getType(),this);
468      assert(Init != 0 && "Wasn't a simple constant init?");
469
470      llvm::Value *AlignVal =
471        llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), Align);
472      const llvm::Type *IntPtr =
473        llvm::IntegerType::get(VMContext, LLVMPointerWidth);
474      llvm::Value *SizeVal =
475        llvm::ConstantInt::get(IntPtr,
476                               getContext().getTypeSizeInChars(Ty).getRaw());
477
478      const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext);
479      if (Loc->getType() != BP)
480        Loc = Builder.CreateBitCast(Loc, BP, "tmp");
481
482      // If the initializer is all zeros, codegen with memset.
483      if (isa<llvm::ConstantAggregateZero>(Init)) {
484        llvm::Value *Zero =
485          llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext), 0);
486        Builder.CreateCall4(CGM.getMemSetFn(), Loc, Zero, SizeVal, AlignVal);
487      } else {
488        // Otherwise, create a temporary global with the initializer then
489        // memcpy from the global to the alloca.
490        std::string Name = GetStaticDeclName(*this, D, ".");
491        llvm::GlobalVariable *GV =
492          new llvm::GlobalVariable(CGM.getModule(), Init->getType(), true,
493                                   llvm::GlobalValue::InternalLinkage,
494                                   Init, Name, 0, false, 0);
495        GV->setAlignment(Align);
496
497        llvm::Value *SrcPtr = GV;
498        if (SrcPtr->getType() != BP)
499          SrcPtr = Builder.CreateBitCast(SrcPtr, BP, "tmp");
500
501        Builder.CreateCall4(CGM.getMemCpyFn(), Loc, SrcPtr, SizeVal, AlignVal);
502      }
503    } else if (Ty->isReferenceType()) {
504      RValue RV = EmitReferenceBindingToExpr(Init, Ty, /*IsInitializer=*/true);
505      EmitStoreOfScalar(RV.getScalarVal(), Loc, false, Ty);
506    } else if (!hasAggregateLLVMType(Init->getType())) {
507      llvm::Value *V = EmitScalarExpr(Init);
508      EmitStoreOfScalar(V, Loc, isVolatile, D.getType());
509    } else if (Init->getType()->isAnyComplexType()) {
510      EmitComplexExprIntoAddr(Init, Loc, isVolatile);
511    } else {
512      EmitAggExpr(Init, Loc, isVolatile);
513    }
514  }
515
516  if (isByRef) {
517    const llvm::PointerType *PtrToInt8Ty = llvm::Type::getInt8PtrTy(VMContext);
518
519    EnsureInsertPoint();
520    llvm::Value *isa_field = Builder.CreateStructGEP(DeclPtr, 0);
521    llvm::Value *forwarding_field = Builder.CreateStructGEP(DeclPtr, 1);
522    llvm::Value *flags_field = Builder.CreateStructGEP(DeclPtr, 2);
523    llvm::Value *size_field = Builder.CreateStructGEP(DeclPtr, 3);
524    llvm::Value *V;
525    int flag = 0;
526    int flags = 0;
527
528    needsDispose = true;
529
530    if (Ty->isBlockPointerType()) {
531      flag |= BLOCK_FIELD_IS_BLOCK;
532      flags |= BLOCK_HAS_COPY_DISPOSE;
533    } else if (BlockRequiresCopying(Ty)) {
534      flag |= BLOCK_FIELD_IS_OBJECT;
535      flags |= BLOCK_HAS_COPY_DISPOSE;
536    }
537
538    // FIXME: Someone double check this.
539    if (Ty.isObjCGCWeak())
540      flag |= BLOCK_FIELD_IS_WEAK;
541
542    int isa = 0;
543    if (flag&BLOCK_FIELD_IS_WEAK)
544      isa = 1;
545    V = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), isa);
546    V = Builder.CreateIntToPtr(V, PtrToInt8Ty, "isa");
547    Builder.CreateStore(V, isa_field);
548
549    Builder.CreateStore(DeclPtr, forwarding_field);
550
551    V = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), flags);
552    Builder.CreateStore(V, flags_field);
553
554    const llvm::Type *V1;
555    V1 = cast<llvm::PointerType>(DeclPtr->getType())->getElementType();
556    V = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
557                               (CGM.getTargetData().getTypeStoreSizeInBits(V1)
558                                / 8));
559    Builder.CreateStore(V, size_field);
560
561    if (flags & BLOCK_HAS_COPY_DISPOSE) {
562      BlockHasCopyDispose = true;
563      llvm::Value *copy_helper = Builder.CreateStructGEP(DeclPtr, 4);
564      Builder.CreateStore(BuildbyrefCopyHelper(DeclPtr->getType(), flag, Align),
565                          copy_helper);
566
567      llvm::Value *destroy_helper = Builder.CreateStructGEP(DeclPtr, 5);
568      Builder.CreateStore(BuildbyrefDestroyHelper(DeclPtr->getType(), flag,
569                                                  Align),
570                          destroy_helper);
571    }
572  }
573
574  // Handle CXX destruction of variables.
575  QualType DtorTy(Ty);
576  while (const ArrayType *Array = getContext().getAsArrayType(DtorTy))
577    DtorTy = getContext().getBaseElementType(Array);
578  if (const RecordType *RT = DtorTy->getAs<RecordType>())
579    if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
580      if (!ClassDecl->hasTrivialDestructor()) {
581        const CXXDestructorDecl *D = ClassDecl->getDestructor(getContext());
582        assert(D && "EmitLocalBlockVarDecl - destructor is nul");
583
584        if (const ConstantArrayType *Array =
585              getContext().getAsConstantArrayType(Ty)) {
586          {
587            DelayedCleanupBlock Scope(*this);
588            QualType BaseElementTy = getContext().getBaseElementType(Array);
589            const llvm::Type *BasePtr = ConvertType(BaseElementTy);
590            BasePtr = llvm::PointerType::getUnqual(BasePtr);
591            llvm::Value *BaseAddrPtr =
592              Builder.CreateBitCast(DeclPtr, BasePtr);
593            EmitCXXAggrDestructorCall(D, Array, BaseAddrPtr);
594
595            // Make sure to jump to the exit block.
596            EmitBranch(Scope.getCleanupExitBlock());
597          }
598          if (Exceptions) {
599            EHCleanupBlock Cleanup(*this);
600            QualType BaseElementTy = getContext().getBaseElementType(Array);
601            const llvm::Type *BasePtr = ConvertType(BaseElementTy);
602            BasePtr = llvm::PointerType::getUnqual(BasePtr);
603            llvm::Value *BaseAddrPtr =
604              Builder.CreateBitCast(DeclPtr, BasePtr);
605            EmitCXXAggrDestructorCall(D, Array, BaseAddrPtr);
606          }
607        } else {
608          {
609            DelayedCleanupBlock Scope(*this);
610            EmitCXXDestructorCall(D, Dtor_Complete, DeclPtr);
611
612            // Make sure to jump to the exit block.
613            EmitBranch(Scope.getCleanupExitBlock());
614          }
615          if (Exceptions) {
616            EHCleanupBlock Cleanup(*this);
617            EmitCXXDestructorCall(D, Dtor_Complete, DeclPtr);
618          }
619        }
620      }
621  }
622
623  // Handle the cleanup attribute
624  if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
625    const FunctionDecl *FD = CA->getFunctionDecl();
626
627    llvm::Constant* F = CGM.GetAddrOfFunction(FD);
628    assert(F && "Could not find function!");
629
630    const CGFunctionInfo &Info = CGM.getTypes().getFunctionInfo(FD);
631
632    // In some cases, the type of the function argument will be different from
633    // the type of the pointer. An example of this is
634    // void f(void* arg);
635    // __attribute__((cleanup(f))) void *g;
636    //
637    // To fix this we insert a bitcast here.
638    QualType ArgTy = Info.arg_begin()->type;
639    {
640      DelayedCleanupBlock scope(*this);
641
642      CallArgList Args;
643      Args.push_back(std::make_pair(RValue::get(Builder.CreateBitCast(DeclPtr,
644                                                           ConvertType(ArgTy))),
645                                    getContext().getPointerType(D.getType())));
646      EmitCall(Info, F, ReturnValueSlot(), Args);
647    }
648    if (Exceptions) {
649      EHCleanupBlock Cleanup(*this);
650
651      CallArgList Args;
652      Args.push_back(std::make_pair(RValue::get(Builder.CreateBitCast(DeclPtr,
653                                                           ConvertType(ArgTy))),
654                                    getContext().getPointerType(D.getType())));
655      EmitCall(Info, F, ReturnValueSlot(), Args);
656    }
657  }
658
659  if (needsDispose && CGM.getLangOptions().getGCMode() != LangOptions::GCOnly) {
660    {
661      DelayedCleanupBlock scope(*this);
662      llvm::Value *V = Builder.CreateStructGEP(DeclPtr, 1, "forwarding");
663      V = Builder.CreateLoad(V);
664      BuildBlockRelease(V);
665    }
666    // FIXME: Turn this on and audit the codegen
667    if (0 && Exceptions) {
668      EHCleanupBlock Cleanup(*this);
669      llvm::Value *V = Builder.CreateStructGEP(DeclPtr, 1, "forwarding");
670      V = Builder.CreateLoad(V);
671      BuildBlockRelease(V);
672    }
673  }
674}
675
676/// Emit an alloca (or GlobalValue depending on target)
677/// for the specified parameter and set up LocalDeclMap.
678void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg) {
679  // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
680  assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
681         "Invalid argument to EmitParmDecl");
682  QualType Ty = D.getType();
683  CanQualType CTy = getContext().getCanonicalType(Ty);
684
685  llvm::Value *DeclPtr;
686  if (!Ty->isConstantSizeType()) {
687    // Variable sized values always are passed by-reference.
688    DeclPtr = Arg;
689  } else {
690    // A fixed sized single-value variable becomes an alloca in the entry block.
691    const llvm::Type *LTy = ConvertTypeForMem(Ty);
692    if (LTy->isSingleValueType()) {
693      // TODO: Alignment
694      DeclPtr = CreateTempAlloca(LTy);
695      DeclPtr->setName(D.getNameAsString() + llvm::StringRef(".addr"));
696
697      // Store the initial value into the alloca.
698      EmitStoreOfScalar(Arg, DeclPtr, CTy.isVolatileQualified(), Ty);
699    } else {
700      // Otherwise, if this is an aggregate, just use the input pointer.
701      DeclPtr = Arg;
702    }
703    Arg->setName(D.getNameAsString());
704  }
705
706  llvm::Value *&DMEntry = LocalDeclMap[&D];
707  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
708  DMEntry = DeclPtr;
709
710  // Emit debug info for param declaration.
711  if (CGDebugInfo *DI = getDebugInfo()) {
712    DI->setLocation(D.getLocation());
713    DI->EmitDeclareOfArgVariable(&D, DeclPtr, Builder);
714  }
715}
716