CGDecl.cpp revision a4d6ca174b7b8ffeee7392e74b69242f78e94b51 
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/Decl.h"
19#include "clang/AST/DeclObjC.h"
20#include "clang/Basic/SourceManager.h"
21#include "clang/Basic/TargetInfo.h"
22#include "clang/CodeGen/CodeGenOptions.h"
23#include "llvm/GlobalVariable.h"
24#include "llvm/Intrinsics.h"
25#include "llvm/Target/TargetData.h"
26#include "llvm/Type.h"
27using namespace clang;
28using namespace CodeGen;
29
30
31void CodeGenFunction::EmitDecl(const Decl &D) {
32  switch (D.getKind()) {
33  default:
34    CGM.ErrorUnsupported(&D, "decl");
35    return;
36  case Decl::ParmVar:
37    assert(0 && "Parmdecls should not be in declstmts!");
38  case Decl::Function:  // void X();
39  case Decl::Record:    // struct/union/class X;
40  case Decl::Enum:      // enum X;
41  case Decl::EnumConstant: // enum ? { X = ? }
42  case Decl::CXXRecord: // struct/union/class X; [C++]
43  case Decl::Using:          // using X; [C++]
44  case Decl::UsingShadow:
45  case Decl::UsingDirective: // using namespace X; [C++]
46  case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
47    // None of these decls require codegen support.
48    return;
49
50  case Decl::Var: {
51    const VarDecl &VD = cast<VarDecl>(D);
52    assert(VD.isBlockVarDecl() &&
53           "Should not see file-scope variables inside a function!");
54    return EmitBlockVarDecl(VD);
55  }
56
57  case Decl::Typedef: {   // typedef int X;
58    const TypedefDecl &TD = cast<TypedefDecl>(D);
59    QualType Ty = TD.getUnderlyingType();
60
61    if (Ty->isVariablyModifiedType())
62      EmitVLASize(Ty);
63  }
64  }
65}
66
67/// EmitBlockVarDecl - This method handles emission of any variable declaration
68/// inside a function, including static vars etc.
69void CodeGenFunction::EmitBlockVarDecl(const VarDecl &D) {
70  if (D.hasAttr<AsmLabelAttr>())
71    CGM.ErrorUnsupported(&D, "__asm__");
72
73  switch (D.getStorageClass()) {
74  case VarDecl::None:
75  case VarDecl::Auto:
76  case VarDecl::Register:
77    return EmitLocalBlockVarDecl(D);
78  case VarDecl::Static:
79    return EmitStaticBlockVarDecl(D);
80  case VarDecl::Extern:
81  case VarDecl::PrivateExtern:
82    // Don't emit it now, allow it to be emitted lazily on its first use.
83    return;
84  }
85
86  assert(0 && "Unknown storage class");
87}
88
89static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D,
90                                     const char *Separator) {
91  CodeGenModule &CGM = CGF.CGM;
92  if (CGF.getContext().getLangOptions().CPlusPlus)
93    return CGM.getMangledName(&D);
94
95  std::string ContextName;
96  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl))
97    ContextName = CGM.getMangledName(FD);
98  else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl))
99    ContextName = CGF.CurFn->getName();
100  else
101    // FIXME: What about in a block??
102    assert(0 && "Unknown context for block var decl");
103
104  return ContextName + Separator + D.getNameAsString();
105}
106
107llvm::GlobalVariable *
108CodeGenFunction::CreateStaticBlockVarDecl(const VarDecl &D,
109                                          const char *Separator,
110                                      llvm::GlobalValue::LinkageTypes Linkage) {
111  QualType Ty = D.getType();
112  assert(Ty->isConstantSizeType() && "VLAs can't be static");
113
114  std::string Name = GetStaticDeclName(*this, D, Separator);
115
116  const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty);
117  llvm::GlobalVariable *GV =
118    new llvm::GlobalVariable(CGM.getModule(), LTy,
119                             Ty.isConstant(getContext()), Linkage,
120                             CGM.EmitNullConstant(D.getType()), Name, 0,
121                             D.isThreadSpecified(), Ty.getAddressSpace());
122  GV->setAlignment(getContext().getDeclAlignInBytes(&D));
123  return GV;
124}
125
126/// AddInitializerToGlobalBlockVarDecl - Add the initializer for 'D' to the
127/// global variable that has already been created for it.  If the initializer
128/// has a different type than GV does, this may free GV and return a different
129/// one.  Otherwise it just returns GV.
130llvm::GlobalVariable *
131CodeGenFunction::AddInitializerToGlobalBlockVarDecl(const VarDecl &D,
132                                                    llvm::GlobalVariable *GV) {
133  llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(), D.getType(), this);
134
135  // If constant emission failed, then this should be a C++ static
136  // initializer.
137  if (!Init) {
138    if (!getContext().getLangOptions().CPlusPlus)
139      CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
140    else
141      EmitStaticCXXBlockVarDeclInit(D, GV);
142    return GV;
143  }
144
145  // The initializer may differ in type from the global. Rewrite
146  // the global to match the initializer.  (We have to do this
147  // because some types, like unions, can't be completely represented
148  // in the LLVM type system.)
149  if (GV->getType() != Init->getType()) {
150    llvm::GlobalVariable *OldGV = GV;
151
152    GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
153                                  OldGV->isConstant(),
154                                  OldGV->getLinkage(), Init, "",
155                                  0, D.isThreadSpecified(),
156                                  D.getType().getAddressSpace());
157
158    // Steal the name of the old global
159    GV->takeName(OldGV);
160
161    // Replace all uses of the old global with the new global
162    llvm::Constant *NewPtrForOldDecl =
163    llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
164    OldGV->replaceAllUsesWith(NewPtrForOldDecl);
165
166    // Erase the old global, since it is no longer used.
167    OldGV->eraseFromParent();
168  }
169
170  GV->setInitializer(Init);
171  return GV;
172}
173
174void CodeGenFunction::EmitStaticBlockVarDecl(const VarDecl &D) {
175  llvm::Value *&DMEntry = LocalDeclMap[&D];
176  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
177
178  llvm::GlobalVariable *GV =
179    CreateStaticBlockVarDecl(D, ".", llvm::GlobalValue::InternalLinkage);
180
181  // Store into LocalDeclMap before generating initializer to handle
182  // circular references.
183  DMEntry = GV;
184
185  // Make sure to evaluate VLA bounds now so that we have them for later.
186  //
187  // FIXME: Can this happen?
188  if (D.getType()->isVariablyModifiedType())
189    EmitVLASize(D.getType());
190
191  // If this value has an initializer, emit it.
192  if (D.getInit())
193    GV = AddInitializerToGlobalBlockVarDecl(D, GV);
194
195  // FIXME: Merge attribute handling.
196  if (const AnnotateAttr *AA = D.getAttr<AnnotateAttr>()) {
197    SourceManager &SM = CGM.getContext().getSourceManager();
198    llvm::Constant *Ann =
199      CGM.EmitAnnotateAttr(GV, AA,
200                           SM.getInstantiationLineNumber(D.getLocation()));
201    CGM.AddAnnotation(Ann);
202  }
203
204  if (const SectionAttr *SA = D.getAttr<SectionAttr>())
205    GV->setSection(SA->getName());
206
207  if (D.hasAttr<UsedAttr>())
208    CGM.AddUsedGlobal(GV);
209
210  // We may have to cast the constant because of the initializer
211  // mismatch above.
212  //
213  // FIXME: It is really dangerous to store this in the map; if anyone
214  // RAUW's the GV uses of this constant will be invalid.
215  const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(D.getType());
216  const llvm::Type *LPtrTy =
217    llvm::PointerType::get(LTy, D.getType().getAddressSpace());
218  DMEntry = llvm::ConstantExpr::getBitCast(GV, LPtrTy);
219
220  // Emit global variable debug descriptor for static vars.
221  CGDebugInfo *DI = getDebugInfo();
222  if (DI) {
223    DI->setLocation(D.getLocation());
224    DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(GV), &D);
225  }
226}
227
228unsigned CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const {
229  assert(ByRefValueInfo.count(VD) && "Did not find value!");
230
231  return ByRefValueInfo.find(VD)->second.second;
232}
233
234/// BuildByRefType - This routine changes a __block variable declared as T x
235///   into:
236///
237///      struct {
238///        void *__isa;
239///        void *__forwarding;
240///        int32_t __flags;
241///        int32_t __size;
242///        void *__copy_helper;       // only if needed
243///        void *__destroy_helper;    // only if needed
244///        char padding[X];           // only if needed
245///        T x;
246///      } x
247///
248const llvm::Type *CodeGenFunction::BuildByRefType(const ValueDecl *D) {
249  std::pair<const llvm::Type *, unsigned> &Info = ByRefValueInfo[D];
250  if (Info.first)
251    return Info.first;
252
253  QualType Ty = D->getType();
254
255  std::vector<const llvm::Type *> Types;
256
257  const llvm::PointerType *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
258
259  llvm::PATypeHolder ByRefTypeHolder = llvm::OpaqueType::get(VMContext);
260
261  // void *__isa;
262  Types.push_back(Int8PtrTy);
263
264  // void *__forwarding;
265  Types.push_back(llvm::PointerType::getUnqual(ByRefTypeHolder));
266
267  // int32_t __flags;
268  Types.push_back(llvm::Type::getInt32Ty(VMContext));
269
270  // int32_t __size;
271  Types.push_back(llvm::Type::getInt32Ty(VMContext));
272
273  bool HasCopyAndDispose = BlockRequiresCopying(Ty);
274  if (HasCopyAndDispose) {
275    /// void *__copy_helper;
276    Types.push_back(Int8PtrTy);
277
278    /// void *__destroy_helper;
279    Types.push_back(Int8PtrTy);
280  }
281
282  bool Packed = false;
283  unsigned Align = getContext().getDeclAlignInBytes(D);
284  if (Align > Target.getPointerAlign(0) / 8) {
285    // We have to insert padding.
286
287    // The struct above has 2 32-bit integers.
288    unsigned CurrentOffsetInBytes = 4 * 2;
289
290    // And either 2 or 4 pointers.
291    CurrentOffsetInBytes += (HasCopyAndDispose ? 4 : 2) *
292      CGM.getTargetData().getTypeAllocSize(Int8PtrTy);
293
294    // Align the offset.
295    unsigned AlignedOffsetInBytes =
296      llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align);
297
298    unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes;
299    if (NumPaddingBytes > 0) {
300      const llvm::Type *Ty = llvm::Type::getInt8Ty(VMContext);
301      // FIXME: We need a sema error for alignment larger than the minimum of
302      // the maximal stack alignmint and the alignment of malloc on the system.
303      if (NumPaddingBytes > 1)
304        Ty = llvm::ArrayType::get(Ty, NumPaddingBytes);
305
306      Types.push_back(Ty);
307
308      // We want a packed struct.
309      Packed = true;
310    }
311  }
312
313  // T x;
314  Types.push_back(ConvertType(Ty));
315
316  const llvm::Type *T = llvm::StructType::get(VMContext, Types, Packed);
317
318  cast<llvm::OpaqueType>(ByRefTypeHolder.get())->refineAbstractTypeTo(T);
319  CGM.getModule().addTypeName("struct.__block_byref_" + D->getNameAsString(),
320                              ByRefTypeHolder.get());
321
322  Info.first = ByRefTypeHolder.get();
323
324  Info.second = Types.size() - 1;
325
326  return Info.first;
327}
328
329/// EmitLocalBlockVarDecl - Emit code and set up an entry in LocalDeclMap for a
330/// variable declaration with auto, register, or no storage class specifier.
331/// These turn into simple stack objects, or GlobalValues depending on target.
332void CodeGenFunction::EmitLocalBlockVarDecl(const VarDecl &D) {
333  QualType Ty = D.getType();
334  bool isByRef = D.hasAttr<BlocksAttr>();
335  bool needsDispose = false;
336  unsigned Align = 0;
337  bool IsSimpleConstantInitializer = false;
338
339  llvm::Value *DeclPtr;
340  if (Ty->isConstantSizeType()) {
341    if (!Target.useGlobalsForAutomaticVariables()) {
342
343      // If this value is an array or struct, is POD, and if the initializer is
344      // a staticly determinable constant, try to optimize it.
345      if (D.getInit() && !isByRef &&
346          (Ty->isArrayType() || Ty->isRecordType()) &&
347          Ty->isPODType() &&
348          D.getInit()->isConstantInitializer(getContext())) {
349        // If this variable is marked 'const', emit the value as a global.
350        if (CGM.getCodeGenOpts().MergeAllConstants &&
351            Ty.isConstant(getContext())) {
352          EmitStaticBlockVarDecl(D);
353          return;
354        }
355
356        IsSimpleConstantInitializer = true;
357      }
358
359      // A normal fixed sized variable becomes an alloca in the entry block.
360      const llvm::Type *LTy = ConvertTypeForMem(Ty);
361      if (isByRef)
362        LTy = BuildByRefType(&D);
363      llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
364      Alloc->setName(D.getNameAsString().c_str());
365
366      Align = getContext().getDeclAlignInBytes(&D);
367      if (isByRef)
368        Align = std::max(Align, unsigned(Target.getPointerAlign(0) / 8));
369      Alloc->setAlignment(Align);
370      DeclPtr = Alloc;
371    } else {
372      // Targets that don't support recursion emit locals as globals.
373      const char *Class =
374        D.getStorageClass() == VarDecl::Register ? ".reg." : ".auto.";
375      DeclPtr = CreateStaticBlockVarDecl(D, Class,
376                                         llvm::GlobalValue
377                                         ::InternalLinkage);
378    }
379
380    // FIXME: Can this happen?
381    if (Ty->isVariablyModifiedType())
382      EmitVLASize(Ty);
383  } else {
384    EnsureInsertPoint();
385
386    if (!DidCallStackSave) {
387      // Save the stack.
388      const llvm::Type *LTy = llvm::Type::getInt8PtrTy(VMContext);
389      llvm::Value *Stack = CreateTempAlloca(LTy, "saved_stack");
390
391      llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
392      llvm::Value *V = Builder.CreateCall(F);
393
394      Builder.CreateStore(V, Stack);
395
396      DidCallStackSave = true;
397
398      {
399        // Push a cleanup block and restore the stack there.
400        DelayedCleanupBlock scope(*this);
401
402        V = Builder.CreateLoad(Stack, "tmp");
403        llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
404        Builder.CreateCall(F, V);
405      }
406    }
407
408    // Get the element type.
409    const llvm::Type *LElemTy = ConvertTypeForMem(Ty);
410    const llvm::Type *LElemPtrTy =
411      llvm::PointerType::get(LElemTy, D.getType().getAddressSpace());
412
413    llvm::Value *VLASize = EmitVLASize(Ty);
414
415    // Downcast the VLA size expression
416    VLASize = Builder.CreateIntCast(VLASize, llvm::Type::getInt32Ty(VMContext),
417                                    false, "tmp");
418
419    // Allocate memory for the array.
420    llvm::AllocaInst *VLA =
421      Builder.CreateAlloca(llvm::Type::getInt8Ty(VMContext), VLASize, "vla");
422    VLA->setAlignment(getContext().getDeclAlignInBytes(&D));
423
424    DeclPtr = Builder.CreateBitCast(VLA, LElemPtrTy, "tmp");
425  }
426
427  llvm::Value *&DMEntry = LocalDeclMap[&D];
428  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
429  DMEntry = DeclPtr;
430
431  // Emit debug info for local var declaration.
432  if (CGDebugInfo *DI = getDebugInfo()) {
433    assert(HaveInsertPoint() && "Unexpected unreachable point!");
434
435    DI->setLocation(D.getLocation());
436    if (Target.useGlobalsForAutomaticVariables()) {
437      DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(DeclPtr), &D);
438    } else
439      DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
440  }
441
442  // If this local has an initializer, emit it now.
443  const Expr *Init = D.getInit();
444
445  // If we are at an unreachable point, we don't need to emit the initializer
446  // unless it contains a label.
447  if (!HaveInsertPoint()) {
448    if (!ContainsLabel(Init))
449      Init = 0;
450    else
451      EnsureInsertPoint();
452  }
453
454  if (Init) {
455    llvm::Value *Loc = DeclPtr;
456    if (isByRef)
457      Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
458                                    D.getNameAsString());
459
460    bool isVolatile =
461      getContext().getCanonicalType(D.getType()).isVolatileQualified();
462
463    // If the initializer was a simple constant initializer, we can optimize it
464    // in various ways.
465    if (IsSimpleConstantInitializer) {
466      llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(),D.getType(),this);
467      assert(Init != 0 && "Wasn't a simple constant init?");
468
469      llvm::Value *AlignVal =
470        llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), Align);
471      const llvm::Type *IntPtr =
472        llvm::IntegerType::get(VMContext, LLVMPointerWidth);
473      llvm::Value *SizeVal =
474        llvm::ConstantInt::get(IntPtr, getContext().getTypeSizeInBytes(Ty));
475
476      const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext);
477      if (Loc->getType() != BP)
478        Loc = Builder.CreateBitCast(Loc, BP, "tmp");
479
480      // If the initializer is all zeros, codegen with memset.
481      if (isa<llvm::ConstantAggregateZero>(Init)) {
482        llvm::Value *Zero =
483          llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext), 0);
484        Builder.CreateCall4(CGM.getMemSetFn(), Loc, Zero, SizeVal, AlignVal);
485      } else {
486        // Otherwise, create a temporary global with the initializer then
487        // memcpy from the global to the alloca.
488        std::string Name = GetStaticDeclName(*this, D, ".");
489        llvm::GlobalVariable *GV =
490          new llvm::GlobalVariable(CGM.getModule(), Init->getType(), true,
491                                   llvm::GlobalValue::InternalLinkage,
492                                   Init, Name, 0, false, 0);
493        GV->setAlignment(Align);
494
495        llvm::Value *SrcPtr = GV;
496        if (SrcPtr->getType() != BP)
497          SrcPtr = Builder.CreateBitCast(SrcPtr, BP, "tmp");
498
499        Builder.CreateCall4(CGM.getMemCpyFn(), Loc, SrcPtr, SizeVal, AlignVal);
500      }
501    } else if (Ty->isReferenceType()) {
502      RValue RV = EmitReferenceBindingToExpr(Init, Ty, /*IsInitializer=*/true);
503      EmitStoreOfScalar(RV.getScalarVal(), Loc, false, Ty);
504    } else if (!hasAggregateLLVMType(Init->getType())) {
505      llvm::Value *V = EmitScalarExpr(Init);
506      EmitStoreOfScalar(V, Loc, isVolatile, D.getType());
507    } else if (Init->getType()->isAnyComplexType()) {
508      EmitComplexExprIntoAddr(Init, Loc, isVolatile);
509    } else {
510      EmitAggExpr(Init, Loc, isVolatile);
511    }
512  }
513
514  if (isByRef) {
515    const llvm::PointerType *PtrToInt8Ty = llvm::Type::getInt8PtrTy(VMContext);
516
517    EnsureInsertPoint();
518    llvm::Value *isa_field = Builder.CreateStructGEP(DeclPtr, 0);
519    llvm::Value *forwarding_field = Builder.CreateStructGEP(DeclPtr, 1);
520    llvm::Value *flags_field = Builder.CreateStructGEP(DeclPtr, 2);
521    llvm::Value *size_field = Builder.CreateStructGEP(DeclPtr, 3);
522    llvm::Value *V;
523    int flag = 0;
524    int flags = 0;
525
526    needsDispose = true;
527
528    if (Ty->isBlockPointerType()) {
529      flag |= BLOCK_FIELD_IS_BLOCK;
530      flags |= BLOCK_HAS_COPY_DISPOSE;
531    } else if (BlockRequiresCopying(Ty)) {
532      flag |= BLOCK_FIELD_IS_OBJECT;
533      flags |= BLOCK_HAS_COPY_DISPOSE;
534    }
535
536    // FIXME: Someone double check this.
537    if (Ty.isObjCGCWeak())
538      flag |= BLOCK_FIELD_IS_WEAK;
539
540    int isa = 0;
541    if (flag&BLOCK_FIELD_IS_WEAK)
542      isa = 1;
543    V = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), isa);
544    V = Builder.CreateIntToPtr(V, PtrToInt8Ty, "isa");
545    Builder.CreateStore(V, isa_field);
546
547    Builder.CreateStore(DeclPtr, forwarding_field);
548
549    V = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), flags);
550    Builder.CreateStore(V, flags_field);
551
552    const llvm::Type *V1;
553    V1 = cast<llvm::PointerType>(DeclPtr->getType())->getElementType();
554    V = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
555                               (CGM.getTargetData().getTypeStoreSizeInBits(V1)
556                                / 8));
557    Builder.CreateStore(V, size_field);
558
559    if (flags & BLOCK_HAS_COPY_DISPOSE) {
560      BlockHasCopyDispose = true;
561      llvm::Value *copy_helper = Builder.CreateStructGEP(DeclPtr, 4);
562      Builder.CreateStore(BuildbyrefCopyHelper(DeclPtr->getType(), flag, Align),
563                          copy_helper);
564
565      llvm::Value *destroy_helper = Builder.CreateStructGEP(DeclPtr, 5);
566      Builder.CreateStore(BuildbyrefDestroyHelper(DeclPtr->getType(), flag,
567                                                  Align),
568                          destroy_helper);
569    }
570  }
571
572  // Handle CXX destruction of variables.
573  QualType DtorTy(Ty);
574  while (const ArrayType *Array = getContext().getAsArrayType(DtorTy))
575    DtorTy = getContext().getBaseElementType(Array);
576  if (const RecordType *RT = DtorTy->getAs<RecordType>())
577    if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
578      if (!ClassDecl->hasTrivialDestructor()) {
579        const CXXDestructorDecl *D = ClassDecl->getDestructor(getContext());
580        assert(D && "EmitLocalBlockVarDecl - destructor is nul");
581
582        if (const ConstantArrayType *Array =
583              getContext().getAsConstantArrayType(Ty)) {
584          DelayedCleanupBlock Scope(*this);
585          QualType BaseElementTy = getContext().getBaseElementType(Array);
586          const llvm::Type *BasePtr = ConvertType(BaseElementTy);
587          BasePtr = llvm::PointerType::getUnqual(BasePtr);
588          llvm::Value *BaseAddrPtr =
589            Builder.CreateBitCast(DeclPtr, BasePtr);
590          EmitCXXAggrDestructorCall(D, Array, BaseAddrPtr);
591
592          // Make sure to jump to the exit block.
593          EmitBranch(Scope.getCleanupExitBlock());
594        } else {
595          DelayedCleanupBlock Scope(*this);
596          EmitCXXDestructorCall(D, Dtor_Complete, DeclPtr);
597
598          // Make sure to jump to the exit block.
599          EmitBranch(Scope.getCleanupExitBlock());
600        }
601      }
602  }
603
604  // Handle the cleanup attribute
605  if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
606    const FunctionDecl *FD = CA->getFunctionDecl();
607
608    llvm::Constant* F = CGM.GetAddrOfFunction(FD);
609    assert(F && "Could not find function!");
610
611    DelayedCleanupBlock scope(*this);
612
613    const CGFunctionInfo &Info = CGM.getTypes().getFunctionInfo(FD);
614
615    // In some cases, the type of the function argument will be different from
616    // the type of the pointer. An example of this is
617    // void f(void* arg);
618    // __attribute__((cleanup(f))) void *g;
619    //
620    // To fix this we insert a bitcast here.
621    QualType ArgTy = Info.arg_begin()->type;
622    DeclPtr = Builder.CreateBitCast(DeclPtr, ConvertType(ArgTy));
623
624    CallArgList Args;
625    Args.push_back(std::make_pair(RValue::get(DeclPtr),
626                                  getContext().getPointerType(D.getType())));
627
628    EmitCall(Info, F, Args);
629  }
630
631  if (needsDispose && CGM.getLangOptions().getGCMode() != LangOptions::GCOnly) {
632    DelayedCleanupBlock scope(*this);
633    llvm::Value *V = Builder.CreateStructGEP(DeclPtr, 1, "forwarding");
634    V = Builder.CreateLoad(V);
635    BuildBlockRelease(V);
636  }
637}
638
639/// Emit an alloca (or GlobalValue depending on target)
640/// for the specified parameter and set up LocalDeclMap.
641void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg) {
642  // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
643  assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
644         "Invalid argument to EmitParmDecl");
645  QualType Ty = D.getType();
646  CanQualType CTy = getContext().getCanonicalType(Ty);
647
648  llvm::Value *DeclPtr;
649  if (!Ty->isConstantSizeType()) {
650    // Variable sized values always are passed by-reference.
651    DeclPtr = Arg;
652  } else {
653    // A fixed sized single-value variable becomes an alloca in the entry block.
654    const llvm::Type *LTy = ConvertTypeForMem(Ty);
655    if (LTy->isSingleValueType()) {
656      // TODO: Alignment
657      DeclPtr = CreateTempAlloca(LTy);
658      DeclPtr->setName(D.getNameAsString() + llvm::StringRef(".addr"));
659
660      // Store the initial value into the alloca.
661      EmitStoreOfScalar(Arg, DeclPtr, CTy.isVolatileQualified(), Ty);
662    } else {
663      // Otherwise, if this is an aggregate, just use the input pointer.
664      DeclPtr = Arg;
665    }
666    Arg->setName(D.getNameAsString());
667  }
668
669  llvm::Value *&DMEntry = LocalDeclMap[&D];
670  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
671  DMEntry = DeclPtr;
672
673  // Emit debug info for param declaration.
674  if (CGDebugInfo *DI = getDebugInfo()) {
675    DI->setLocation(D.getLocation());
676    DI->EmitDeclareOfArgVariable(&D, DeclPtr, Builder);
677  }
678}
679