CGDecl.cpp revision 8a07cd3f59a0ede54906bdc8ed21724815db27ad 
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 "CodeGenFunction.h"
15#include "CGDebugInfo.h"
16#include "CGOpenCLRuntime.h"
17#include "CodeGenModule.h"
18#include "clang/AST/ASTContext.h"
19#include "clang/AST/CharUnits.h"
20#include "clang/AST/Decl.h"
21#include "clang/AST/DeclObjC.h"
22#include "clang/Basic/SourceManager.h"
23#include "clang/Basic/TargetInfo.h"
24#include "clang/Frontend/CodeGenOptions.h"
25#include "llvm/IR/DataLayout.h"
26#include "llvm/IR/GlobalVariable.h"
27#include "llvm/IR/Intrinsics.h"
28#include "llvm/IR/Type.h"
29using namespace clang;
30using namespace CodeGen;
31
32
33void CodeGenFunction::EmitDecl(const Decl &D) {
34  switch (D.getKind()) {
35  case Decl::TranslationUnit:
36  case Decl::Namespace:
37  case Decl::UnresolvedUsingTypename:
38  case Decl::ClassTemplateSpecialization:
39  case Decl::ClassTemplatePartialSpecialization:
40  case Decl::TemplateTypeParm:
41  case Decl::UnresolvedUsingValue:
42  case Decl::NonTypeTemplateParm:
43  case Decl::CXXMethod:
44  case Decl::CXXConstructor:
45  case Decl::CXXDestructor:
46  case Decl::CXXConversion:
47  case Decl::Field:
48  case Decl::MSProperty:
49  case Decl::IndirectField:
50  case Decl::ObjCIvar:
51  case Decl::ObjCAtDefsField:
52  case Decl::ParmVar:
53  case Decl::ImplicitParam:
54  case Decl::ClassTemplate:
55  case Decl::FunctionTemplate:
56  case Decl::TypeAliasTemplate:
57  case Decl::TemplateTemplateParm:
58  case Decl::ObjCMethod:
59  case Decl::ObjCCategory:
60  case Decl::ObjCProtocol:
61  case Decl::ObjCInterface:
62  case Decl::ObjCCategoryImpl:
63  case Decl::ObjCImplementation:
64  case Decl::ObjCProperty:
65  case Decl::ObjCCompatibleAlias:
66  case Decl::AccessSpec:
67  case Decl::LinkageSpec:
68  case Decl::ObjCPropertyImpl:
69  case Decl::FileScopeAsm:
70  case Decl::Friend:
71  case Decl::FriendTemplate:
72  case Decl::Block:
73  case Decl::Captured:
74  case Decl::ClassScopeFunctionSpecialization:
75  case Decl::UsingShadow:
76    llvm_unreachable("Declaration should not be in declstmts!");
77  case Decl::Function:  // void X();
78  case Decl::Record:    // struct/union/class X;
79  case Decl::Enum:      // enum X;
80  case Decl::EnumConstant: // enum ? { X = ? }
81  case Decl::CXXRecord: // struct/union/class X; [C++]
82  case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
83  case Decl::Label:        // __label__ x;
84  case Decl::Import:
85  case Decl::OMPThreadPrivate:
86  case Decl::Empty:
87    // None of these decls require codegen support.
88    return;
89
90  case Decl::NamespaceAlias:
91    if (CGDebugInfo *DI = getDebugInfo())
92        DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D));
93    return;
94  case Decl::Using:          // using X; [C++]
95    if (CGDebugInfo *DI = getDebugInfo())
96        DI->EmitUsingDecl(cast<UsingDecl>(D));
97    return;
98  case Decl::UsingDirective: // using namespace X; [C++]
99    if (CGDebugInfo *DI = getDebugInfo())
100      DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D));
101    return;
102  case Decl::Var: {
103    const VarDecl &VD = cast<VarDecl>(D);
104    assert(VD.isLocalVarDecl() &&
105           "Should not see file-scope variables inside a function!");
106    return EmitVarDecl(VD);
107  }
108
109  case Decl::Typedef:      // typedef int X;
110  case Decl::TypeAlias: {  // using X = int; [C++0x]
111    const TypedefNameDecl &TD = cast<TypedefNameDecl>(D);
112    QualType Ty = TD.getUnderlyingType();
113
114    if (Ty->isVariablyModifiedType())
115      EmitVariablyModifiedType(Ty);
116  }
117  }
118}
119
120/// EmitVarDecl - This method handles emission of any variable declaration
121/// inside a function, including static vars etc.
122void CodeGenFunction::EmitVarDecl(const VarDecl &D) {
123  if (D.isStaticLocal()) {
124    llvm::GlobalValue::LinkageTypes Linkage =
125      llvm::GlobalValue::InternalLinkage;
126
127    // If the function definition has some sort of weak linkage, its
128    // static variables should also be weak so that they get properly
129    // uniqued.  We can't do this in C, though, because there's no
130    // standard way to agree on which variables are the same (i.e.
131    // there's no mangling).
132    if (getLangOpts().CPlusPlus)
133      if (llvm::GlobalValue::isWeakForLinker(CurFn->getLinkage()))
134        Linkage = CurFn->getLinkage();
135
136    return EmitStaticVarDecl(D, Linkage);
137  }
138
139  if (D.hasExternalStorage())
140    // Don't emit it now, allow it to be emitted lazily on its first use.
141    return;
142
143  if (D.getStorageClass() == SC_OpenCLWorkGroupLocal)
144    return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D);
145
146  assert(D.hasLocalStorage());
147  return EmitAutoVarDecl(D);
148}
149
150static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D,
151                                     const char *Separator) {
152  CodeGenModule &CGM = CGF.CGM;
153  if (CGF.getLangOpts().CPlusPlus) {
154    StringRef Name = CGM.getMangledName(&D);
155    return Name.str();
156  }
157
158  std::string ContextName;
159  if (!CGF.CurFuncDecl) {
160    // Better be in a block declared in global scope.
161    const NamedDecl *ND = cast<NamedDecl>(&D);
162    const DeclContext *DC = ND->getDeclContext();
163    if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) {
164      MangleBuffer Name;
165      CGM.getBlockMangledName(GlobalDecl(), Name, BD);
166      ContextName = Name.getString();
167    }
168    else
169      llvm_unreachable("Unknown context for block static var decl");
170  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl)) {
171    StringRef Name = CGM.getMangledName(FD);
172    ContextName = Name.str();
173  } else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl))
174    ContextName = CGF.CurFn->getName();
175  else
176    llvm_unreachable("Unknown context for static var decl");
177
178  return ContextName + Separator + D.getNameAsString();
179}
180
181llvm::GlobalVariable *
182CodeGenFunction::CreateStaticVarDecl(const VarDecl &D,
183                                     const char *Separator,
184                                     llvm::GlobalValue::LinkageTypes Linkage) {
185  QualType Ty = D.getType();
186  assert(Ty->isConstantSizeType() && "VLAs can't be static");
187
188  // Use the label if the variable is renamed with the asm-label extension.
189  std::string Name;
190  if (D.hasAttr<AsmLabelAttr>())
191    Name = CGM.getMangledName(&D);
192  else
193    Name = GetStaticDeclName(*this, D, Separator);
194
195  llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty);
196  unsigned AddrSpace =
197   CGM.GetGlobalVarAddressSpace(&D, CGM.getContext().getTargetAddressSpace(Ty));
198  llvm::GlobalVariable *GV =
199    new llvm::GlobalVariable(CGM.getModule(), LTy,
200                             Ty.isConstant(getContext()), Linkage,
201                             CGM.EmitNullConstant(D.getType()), Name, 0,
202                             llvm::GlobalVariable::NotThreadLocal,
203                             AddrSpace);
204  GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
205  if (Linkage != llvm::GlobalValue::InternalLinkage)
206    GV->setVisibility(CurFn->getVisibility());
207
208  if (D.getTLSKind())
209    CGM.setTLSMode(GV, D);
210
211  return GV;
212}
213
214/// hasNontrivialDestruction - Determine whether a type's destruction is
215/// non-trivial. If so, and the variable uses static initialization, we must
216/// register its destructor to run on exit.
217static bool hasNontrivialDestruction(QualType T) {
218  CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
219  return RD && !RD->hasTrivialDestructor();
220}
221
222/// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the
223/// global variable that has already been created for it.  If the initializer
224/// has a different type than GV does, this may free GV and return a different
225/// one.  Otherwise it just returns GV.
226llvm::GlobalVariable *
227CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
228                                               llvm::GlobalVariable *GV) {
229  llvm::Constant *Init = CGM.EmitConstantInit(D, this);
230
231  // If constant emission failed, then this should be a C++ static
232  // initializer.
233  if (!Init) {
234    if (!getLangOpts().CPlusPlus)
235      CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
236    else if (Builder.GetInsertBlock()) {
237      // Since we have a static initializer, this global variable can't
238      // be constant.
239      GV->setConstant(false);
240
241      EmitCXXGuardedInit(D, GV, /*PerformInit*/true);
242    }
243    return GV;
244  }
245
246  // The initializer may differ in type from the global. Rewrite
247  // the global to match the initializer.  (We have to do this
248  // because some types, like unions, can't be completely represented
249  // in the LLVM type system.)
250  if (GV->getType()->getElementType() != Init->getType()) {
251    llvm::GlobalVariable *OldGV = GV;
252
253    GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
254                                  OldGV->isConstant(),
255                                  OldGV->getLinkage(), Init, "",
256                                  /*InsertBefore*/ OldGV,
257                                  OldGV->getThreadLocalMode(),
258                           CGM.getContext().getTargetAddressSpace(D.getType()));
259    GV->setVisibility(OldGV->getVisibility());
260
261    // Steal the name of the old global
262    GV->takeName(OldGV);
263
264    // Replace all uses of the old global with the new global
265    llvm::Constant *NewPtrForOldDecl =
266    llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
267    OldGV->replaceAllUsesWith(NewPtrForOldDecl);
268
269    // Erase the old global, since it is no longer used.
270    OldGV->eraseFromParent();
271  }
272
273  GV->setConstant(CGM.isTypeConstant(D.getType(), true));
274  GV->setInitializer(Init);
275
276  if (hasNontrivialDestruction(D.getType())) {
277    // We have a constant initializer, but a nontrivial destructor. We still
278    // need to perform a guarded "initialization" in order to register the
279    // destructor.
280    EmitCXXGuardedInit(D, GV, /*PerformInit*/false);
281  }
282
283  return GV;
284}
285
286void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
287                                      llvm::GlobalValue::LinkageTypes Linkage) {
288  llvm::Value *&DMEntry = LocalDeclMap[&D];
289  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
290
291  // Check to see if we already have a global variable for this
292  // declaration.  This can happen when double-emitting function
293  // bodies, e.g. with complete and base constructors.
294  llvm::Constant *addr =
295    CGM.getStaticLocalDeclAddress(&D);
296
297  llvm::GlobalVariable *var;
298  if (addr) {
299    var = cast<llvm::GlobalVariable>(addr->stripPointerCasts());
300  } else {
301    addr = var = CreateStaticVarDecl(D, ".", Linkage);
302  }
303
304  // Store into LocalDeclMap before generating initializer to handle
305  // circular references.
306  DMEntry = addr;
307  CGM.setStaticLocalDeclAddress(&D, addr);
308
309  // We can't have a VLA here, but we can have a pointer to a VLA,
310  // even though that doesn't really make any sense.
311  // Make sure to evaluate VLA bounds now so that we have them for later.
312  if (D.getType()->isVariablyModifiedType())
313    EmitVariablyModifiedType(D.getType());
314
315  // Save the type in case adding the initializer forces a type change.
316  llvm::Type *expectedType = addr->getType();
317
318  // If this value has an initializer, emit it.
319  if (D.getInit())
320    var = AddInitializerToStaticVarDecl(D, var);
321
322  var->setAlignment(getContext().getDeclAlign(&D).getQuantity());
323
324  if (D.hasAttr<AnnotateAttr>())
325    CGM.AddGlobalAnnotations(&D, var);
326
327  if (const SectionAttr *SA = D.getAttr<SectionAttr>())
328    var->setSection(SA->getName());
329
330  if (D.hasAttr<UsedAttr>())
331    CGM.AddUsedGlobal(var);
332
333  // We may have to cast the constant because of the initializer
334  // mismatch above.
335  //
336  // FIXME: It is really dangerous to store this in the map; if anyone
337  // RAUW's the GV uses of this constant will be invalid.
338  llvm::Constant *castedAddr = llvm::ConstantExpr::getBitCast(var, expectedType);
339  DMEntry = castedAddr;
340  CGM.setStaticLocalDeclAddress(&D, castedAddr);
341
342  // Emit global variable debug descriptor for static vars.
343  CGDebugInfo *DI = getDebugInfo();
344  if (DI &&
345      CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) {
346    DI->setLocation(D.getLocation());
347    DI->EmitGlobalVariable(var, &D);
348  }
349}
350
351namespace {
352  struct DestroyObject : EHScopeStack::Cleanup {
353    DestroyObject(llvm::Value *addr, QualType type,
354                  CodeGenFunction::Destroyer *destroyer,
355                  bool useEHCleanupForArray)
356      : addr(addr), type(type), destroyer(destroyer),
357        useEHCleanupForArray(useEHCleanupForArray) {}
358
359    llvm::Value *addr;
360    QualType type;
361    CodeGenFunction::Destroyer *destroyer;
362    bool useEHCleanupForArray;
363
364    void Emit(CodeGenFunction &CGF, Flags flags) {
365      // Don't use an EH cleanup recursively from an EH cleanup.
366      bool useEHCleanupForArray =
367        flags.isForNormalCleanup() && this->useEHCleanupForArray;
368
369      CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray);
370    }
371  };
372
373  struct DestroyNRVOVariable : EHScopeStack::Cleanup {
374    DestroyNRVOVariable(llvm::Value *addr,
375                        const CXXDestructorDecl *Dtor,
376                        llvm::Value *NRVOFlag)
377      : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(addr) {}
378
379    const CXXDestructorDecl *Dtor;
380    llvm::Value *NRVOFlag;
381    llvm::Value *Loc;
382
383    void Emit(CodeGenFunction &CGF, Flags flags) {
384      // Along the exceptions path we always execute the dtor.
385      bool NRVO = flags.isForNormalCleanup() && NRVOFlag;
386
387      llvm::BasicBlock *SkipDtorBB = 0;
388      if (NRVO) {
389        // If we exited via NRVO, we skip the destructor call.
390        llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused");
391        SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor");
392        llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val");
393        CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB);
394        CGF.EmitBlock(RunDtorBB);
395      }
396
397      CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
398                                /*ForVirtualBase=*/false,
399                                /*Delegating=*/false,
400                                Loc);
401
402      if (NRVO) CGF.EmitBlock(SkipDtorBB);
403    }
404  };
405
406  struct CallStackRestore : EHScopeStack::Cleanup {
407    llvm::Value *Stack;
408    CallStackRestore(llvm::Value *Stack) : Stack(Stack) {}
409    void Emit(CodeGenFunction &CGF, Flags flags) {
410      llvm::Value *V = CGF.Builder.CreateLoad(Stack);
411      llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
412      CGF.Builder.CreateCall(F, V);
413    }
414  };
415
416  struct ExtendGCLifetime : EHScopeStack::Cleanup {
417    const VarDecl &Var;
418    ExtendGCLifetime(const VarDecl *var) : Var(*var) {}
419
420    void Emit(CodeGenFunction &CGF, Flags flags) {
421      // Compute the address of the local variable, in case it's a
422      // byref or something.
423      DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
424                      Var.getType(), VK_LValue, SourceLocation());
425      llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE));
426      CGF.EmitExtendGCLifetime(value);
427    }
428  };
429
430  struct CallCleanupFunction : EHScopeStack::Cleanup {
431    llvm::Constant *CleanupFn;
432    const CGFunctionInfo &FnInfo;
433    const VarDecl &Var;
434
435    CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
436                        const VarDecl *Var)
437      : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {}
438
439    void Emit(CodeGenFunction &CGF, Flags flags) {
440      DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
441                      Var.getType(), VK_LValue, SourceLocation());
442      // Compute the address of the local variable, in case it's a byref
443      // or something.
444      llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getAddress();
445
446      // In some cases, the type of the function argument will be different from
447      // the type of the pointer. An example of this is
448      // void f(void* arg);
449      // __attribute__((cleanup(f))) void *g;
450      //
451      // To fix this we insert a bitcast here.
452      QualType ArgTy = FnInfo.arg_begin()->type;
453      llvm::Value *Arg =
454        CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy));
455
456      CallArgList Args;
457      Args.add(RValue::get(Arg),
458               CGF.getContext().getPointerType(Var.getType()));
459      CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args);
460    }
461  };
462
463  /// A cleanup to call @llvm.lifetime.end.
464  class CallLifetimeEnd : public EHScopeStack::Cleanup {
465    llvm::Value *Addr;
466    llvm::Value *Size;
467  public:
468    CallLifetimeEnd(llvm::Value *addr, llvm::Value *size)
469      : Addr(addr), Size(size) {}
470
471    void Emit(CodeGenFunction &CGF, Flags flags) {
472      llvm::Value *castAddr = CGF.Builder.CreateBitCast(Addr, CGF.Int8PtrTy);
473      CGF.Builder.CreateCall2(CGF.CGM.getLLVMLifetimeEndFn(),
474                              Size, castAddr)
475        ->setDoesNotThrow();
476    }
477  };
478}
479
480/// EmitAutoVarWithLifetime - Does the setup required for an automatic
481/// variable with lifetime.
482static void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var,
483                                    llvm::Value *addr,
484                                    Qualifiers::ObjCLifetime lifetime) {
485  switch (lifetime) {
486  case Qualifiers::OCL_None:
487    llvm_unreachable("present but none");
488
489  case Qualifiers::OCL_ExplicitNone:
490    // nothing to do
491    break;
492
493  case Qualifiers::OCL_Strong: {
494    CodeGenFunction::Destroyer *destroyer =
495      (var.hasAttr<ObjCPreciseLifetimeAttr>()
496       ? CodeGenFunction::destroyARCStrongPrecise
497       : CodeGenFunction::destroyARCStrongImprecise);
498
499    CleanupKind cleanupKind = CGF.getARCCleanupKind();
500    CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer,
501                    cleanupKind & EHCleanup);
502    break;
503  }
504  case Qualifiers::OCL_Autoreleasing:
505    // nothing to do
506    break;
507
508  case Qualifiers::OCL_Weak:
509    // __weak objects always get EH cleanups; otherwise, exceptions
510    // could cause really nasty crashes instead of mere leaks.
511    CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(),
512                    CodeGenFunction::destroyARCWeak,
513                    /*useEHCleanup*/ true);
514    break;
515  }
516}
517
518static bool isAccessedBy(const VarDecl &var, const Stmt *s) {
519  if (const Expr *e = dyn_cast<Expr>(s)) {
520    // Skip the most common kinds of expressions that make
521    // hierarchy-walking expensive.
522    s = e = e->IgnoreParenCasts();
523
524    if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e))
525      return (ref->getDecl() == &var);
526    if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
527      const BlockDecl *block = be->getBlockDecl();
528      for (BlockDecl::capture_const_iterator i = block->capture_begin(),
529           e = block->capture_end(); i != e; ++i) {
530        if (i->getVariable() == &var)
531          return true;
532      }
533    }
534  }
535
536  for (Stmt::const_child_range children = s->children(); children; ++children)
537    // children might be null; as in missing decl or conditional of an if-stmt.
538    if ((*children) && isAccessedBy(var, *children))
539      return true;
540
541  return false;
542}
543
544static bool isAccessedBy(const ValueDecl *decl, const Expr *e) {
545  if (!decl) return false;
546  if (!isa<VarDecl>(decl)) return false;
547  const VarDecl *var = cast<VarDecl>(decl);
548  return isAccessedBy(*var, e);
549}
550
551static void drillIntoBlockVariable(CodeGenFunction &CGF,
552                                   LValue &lvalue,
553                                   const VarDecl *var) {
554  lvalue.setAddress(CGF.BuildBlockByrefAddress(lvalue.getAddress(), var));
555}
556
557void CodeGenFunction::EmitScalarInit(const Expr *init,
558                                     const ValueDecl *D,
559                                     LValue lvalue,
560                                     bool capturedByInit) {
561  Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
562  if (!lifetime) {
563    llvm::Value *value = EmitScalarExpr(init);
564    if (capturedByInit)
565      drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
566    EmitStoreThroughLValue(RValue::get(value), lvalue, true);
567    return;
568  }
569
570  // If we're emitting a value with lifetime, we have to do the
571  // initialization *before* we leave the cleanup scopes.
572  if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) {
573    enterFullExpression(ewc);
574    init = ewc->getSubExpr();
575  }
576  CodeGenFunction::RunCleanupsScope Scope(*this);
577
578  // We have to maintain the illusion that the variable is
579  // zero-initialized.  If the variable might be accessed in its
580  // initializer, zero-initialize before running the initializer, then
581  // actually perform the initialization with an assign.
582  bool accessedByInit = false;
583  if (lifetime != Qualifiers::OCL_ExplicitNone)
584    accessedByInit = (capturedByInit || isAccessedBy(D, init));
585  if (accessedByInit) {
586    LValue tempLV = lvalue;
587    // Drill down to the __block object if necessary.
588    if (capturedByInit) {
589      // We can use a simple GEP for this because it can't have been
590      // moved yet.
591      tempLV.setAddress(Builder.CreateStructGEP(tempLV.getAddress(),
592                                   getByRefValueLLVMField(cast<VarDecl>(D))));
593    }
594
595    llvm::PointerType *ty
596      = cast<llvm::PointerType>(tempLV.getAddress()->getType());
597    ty = cast<llvm::PointerType>(ty->getElementType());
598
599    llvm::Value *zero = llvm::ConstantPointerNull::get(ty);
600
601    // If __weak, we want to use a barrier under certain conditions.
602    if (lifetime == Qualifiers::OCL_Weak)
603      EmitARCInitWeak(tempLV.getAddress(), zero);
604
605    // Otherwise just do a simple store.
606    else
607      EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true);
608  }
609
610  // Emit the initializer.
611  llvm::Value *value = 0;
612
613  switch (lifetime) {
614  case Qualifiers::OCL_None:
615    llvm_unreachable("present but none");
616
617  case Qualifiers::OCL_ExplicitNone:
618    // nothing to do
619    value = EmitScalarExpr(init);
620    break;
621
622  case Qualifiers::OCL_Strong: {
623    value = EmitARCRetainScalarExpr(init);
624    break;
625  }
626
627  case Qualifiers::OCL_Weak: {
628    // No way to optimize a producing initializer into this.  It's not
629    // worth optimizing for, because the value will immediately
630    // disappear in the common case.
631    value = EmitScalarExpr(init);
632
633    if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
634    if (accessedByInit)
635      EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true);
636    else
637      EmitARCInitWeak(lvalue.getAddress(), value);
638    return;
639  }
640
641  case Qualifiers::OCL_Autoreleasing:
642    value = EmitARCRetainAutoreleaseScalarExpr(init);
643    break;
644  }
645
646  if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
647
648  // If the variable might have been accessed by its initializer, we
649  // might have to initialize with a barrier.  We have to do this for
650  // both __weak and __strong, but __weak got filtered out above.
651  if (accessedByInit && lifetime == Qualifiers::OCL_Strong) {
652    llvm::Value *oldValue = EmitLoadOfScalar(lvalue);
653    EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
654    EmitARCRelease(oldValue, ARCImpreciseLifetime);
655    return;
656  }
657
658  EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
659}
660
661/// EmitScalarInit - Initialize the given lvalue with the given object.
662void CodeGenFunction::EmitScalarInit(llvm::Value *init, LValue lvalue) {
663  Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
664  if (!lifetime)
665    return EmitStoreThroughLValue(RValue::get(init), lvalue, true);
666
667  switch (lifetime) {
668  case Qualifiers::OCL_None:
669    llvm_unreachable("present but none");
670
671  case Qualifiers::OCL_ExplicitNone:
672    // nothing to do
673    break;
674
675  case Qualifiers::OCL_Strong:
676    init = EmitARCRetain(lvalue.getType(), init);
677    break;
678
679  case Qualifiers::OCL_Weak:
680    // Initialize and then skip the primitive store.
681    EmitARCInitWeak(lvalue.getAddress(), init);
682    return;
683
684  case Qualifiers::OCL_Autoreleasing:
685    init = EmitARCRetainAutorelease(lvalue.getType(), init);
686    break;
687  }
688
689  EmitStoreOfScalar(init, lvalue, /* isInitialization */ true);
690}
691
692/// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the
693/// non-zero parts of the specified initializer with equal or fewer than
694/// NumStores scalar stores.
695static bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init,
696                                                unsigned &NumStores) {
697  // Zero and Undef never requires any extra stores.
698  if (isa<llvm::ConstantAggregateZero>(Init) ||
699      isa<llvm::ConstantPointerNull>(Init) ||
700      isa<llvm::UndefValue>(Init))
701    return true;
702  if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
703      isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
704      isa<llvm::ConstantExpr>(Init))
705    return Init->isNullValue() || NumStores--;
706
707  // See if we can emit each element.
708  if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) {
709    for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
710      llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
711      if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
712        return false;
713    }
714    return true;
715  }
716
717  if (llvm::ConstantDataSequential *CDS =
718        dyn_cast<llvm::ConstantDataSequential>(Init)) {
719    for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
720      llvm::Constant *Elt = CDS->getElementAsConstant(i);
721      if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
722        return false;
723    }
724    return true;
725  }
726
727  // Anything else is hard and scary.
728  return false;
729}
730
731/// emitStoresForInitAfterMemset - For inits that
732/// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar
733/// stores that would be required.
734static void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc,
735                                         bool isVolatile, CGBuilderTy &Builder) {
736  assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) &&
737         "called emitStoresForInitAfterMemset for zero or undef value.");
738
739  if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
740      isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
741      isa<llvm::ConstantExpr>(Init)) {
742    Builder.CreateStore(Init, Loc, isVolatile);
743    return;
744  }
745
746  if (llvm::ConstantDataSequential *CDS =
747        dyn_cast<llvm::ConstantDataSequential>(Init)) {
748    for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
749      llvm::Constant *Elt = CDS->getElementAsConstant(i);
750
751      // If necessary, get a pointer to the element and emit it.
752      if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
753        emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
754                                     isVolatile, Builder);
755    }
756    return;
757  }
758
759  assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) &&
760         "Unknown value type!");
761
762  for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
763    llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
764
765    // If necessary, get a pointer to the element and emit it.
766    if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
767      emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
768                                   isVolatile, Builder);
769  }
770}
771
772
773/// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset
774/// plus some stores to initialize a local variable instead of using a memcpy
775/// from a constant global.  It is beneficial to use memset if the global is all
776/// zeros, or mostly zeros and large.
777static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init,
778                                                  uint64_t GlobalSize) {
779  // If a global is all zeros, always use a memset.
780  if (isa<llvm::ConstantAggregateZero>(Init)) return true;
781
782  // If a non-zero global is <= 32 bytes, always use a memcpy.  If it is large,
783  // do it if it will require 6 or fewer scalar stores.
784  // TODO: Should budget depends on the size?  Avoiding a large global warrants
785  // plopping in more stores.
786  unsigned StoreBudget = 6;
787  uint64_t SizeLimit = 32;
788
789  return GlobalSize > SizeLimit &&
790         canEmitInitWithFewStoresAfterMemset(Init, StoreBudget);
791}
792
793/// Should we use the LLVM lifetime intrinsics for the given local variable?
794static bool shouldUseLifetimeMarkers(CodeGenFunction &CGF, const VarDecl &D,
795                                     unsigned Size) {
796  // Always emit lifetime markers in -fsanitize=use-after-scope mode.
797  if (CGF.getLangOpts().Sanitize.UseAfterScope)
798    return true;
799  // For now, only in optimized builds.
800  if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0)
801    return false;
802
803  // Limit the size of marked objects to 32 bytes. We don't want to increase
804  // compile time by marking tiny objects.
805  unsigned SizeThreshold = 32;
806
807  return Size > SizeThreshold;
808}
809
810
811/// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a
812/// variable declaration with auto, register, or no storage class specifier.
813/// These turn into simple stack objects, or GlobalValues depending on target.
814void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
815  AutoVarEmission emission = EmitAutoVarAlloca(D);
816  EmitAutoVarInit(emission);
817  EmitAutoVarCleanups(emission);
818}
819
820/// EmitAutoVarAlloca - Emit the alloca and debug information for a
821/// local variable.  Does not emit initalization or destruction.
822CodeGenFunction::AutoVarEmission
823CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
824  QualType Ty = D.getType();
825
826  AutoVarEmission emission(D);
827
828  bool isByRef = D.hasAttr<BlocksAttr>();
829  emission.IsByRef = isByRef;
830
831  CharUnits alignment = getContext().getDeclAlign(&D);
832  emission.Alignment = alignment;
833
834  // If the type is variably-modified, emit all the VLA sizes for it.
835  if (Ty->isVariablyModifiedType())
836    EmitVariablyModifiedType(Ty);
837
838  llvm::Value *DeclPtr;
839  if (Ty->isConstantSizeType()) {
840    bool NRVO = getLangOpts().ElideConstructors &&
841      D.isNRVOVariable();
842
843    // If this value is an array or struct with a statically determinable
844    // constant initializer, there are optimizations we can do.
845    //
846    // TODO: We should constant-evaluate the initializer of any variable,
847    // as long as it is initialized by a constant expression. Currently,
848    // isConstantInitializer produces wrong answers for structs with
849    // reference or bitfield members, and a few other cases, and checking
850    // for POD-ness protects us from some of these.
851    if (D.getInit() && (Ty->isArrayType() || Ty->isRecordType()) &&
852        (D.isConstexpr() ||
853         ((Ty.isPODType(getContext()) ||
854           getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) &&
855          D.getInit()->isConstantInitializer(getContext(), false)))) {
856
857      // If the variable's a const type, and it's neither an NRVO
858      // candidate nor a __block variable and has no mutable members,
859      // emit it as a global instead.
860      if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef &&
861          CGM.isTypeConstant(Ty, true)) {
862        EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
863
864        emission.Address = 0; // signal this condition to later callbacks
865        assert(emission.wasEmittedAsGlobal());
866        return emission;
867      }
868
869      // Otherwise, tell the initialization code that we're in this case.
870      emission.IsConstantAggregate = true;
871    }
872
873    // A normal fixed sized variable becomes an alloca in the entry block,
874    // unless it's an NRVO variable.
875    llvm::Type *LTy = ConvertTypeForMem(Ty);
876
877    if (NRVO) {
878      // The named return value optimization: allocate this variable in the
879      // return slot, so that we can elide the copy when returning this
880      // variable (C++0x [class.copy]p34).
881      DeclPtr = ReturnValue;
882
883      if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
884        if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) {
885          // Create a flag that is used to indicate when the NRVO was applied
886          // to this variable. Set it to zero to indicate that NRVO was not
887          // applied.
888          llvm::Value *Zero = Builder.getFalse();
889          llvm::Value *NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo");
890          EnsureInsertPoint();
891          Builder.CreateStore(Zero, NRVOFlag);
892
893          // Record the NRVO flag for this variable.
894          NRVOFlags[&D] = NRVOFlag;
895          emission.NRVOFlag = NRVOFlag;
896        }
897      }
898    } else {
899      if (isByRef)
900        LTy = BuildByRefType(&D);
901
902      llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
903      Alloc->setName(D.getName());
904
905      CharUnits allocaAlignment = alignment;
906      if (isByRef)
907        allocaAlignment = std::max(allocaAlignment,
908            getContext().toCharUnitsFromBits(getTarget().getPointerAlign(0)));
909      Alloc->setAlignment(allocaAlignment.getQuantity());
910      DeclPtr = Alloc;
911
912      // Emit a lifetime intrinsic if meaningful.  There's no point
913      // in doing this if we don't have a valid insertion point (?).
914      uint64_t size = CGM.getDataLayout().getTypeAllocSize(LTy);
915      if (HaveInsertPoint() && shouldUseLifetimeMarkers(*this, D, size)) {
916        llvm::Value *sizeV = llvm::ConstantInt::get(Int64Ty, size);
917
918        emission.SizeForLifetimeMarkers = sizeV;
919        llvm::Value *castAddr = Builder.CreateBitCast(Alloc, Int8PtrTy);
920        Builder.CreateCall2(CGM.getLLVMLifetimeStartFn(), sizeV, castAddr)
921          ->setDoesNotThrow();
922      } else {
923        assert(!emission.useLifetimeMarkers());
924      }
925    }
926  } else {
927    EnsureInsertPoint();
928
929    if (!DidCallStackSave) {
930      // Save the stack.
931      llvm::Value *Stack = CreateTempAlloca(Int8PtrTy, "saved_stack");
932
933      llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
934      llvm::Value *V = Builder.CreateCall(F);
935
936      Builder.CreateStore(V, Stack);
937
938      DidCallStackSave = true;
939
940      // Push a cleanup block and restore the stack there.
941      // FIXME: in general circumstances, this should be an EH cleanup.
942      EHStack.pushCleanup<CallStackRestore>(NormalCleanup, Stack);
943    }
944
945    llvm::Value *elementCount;
946    QualType elementType;
947    llvm::tie(elementCount, elementType) = getVLASize(Ty);
948
949    llvm::Type *llvmTy = ConvertTypeForMem(elementType);
950
951    // Allocate memory for the array.
952    llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla");
953    vla->setAlignment(alignment.getQuantity());
954
955    DeclPtr = vla;
956  }
957
958  llvm::Value *&DMEntry = LocalDeclMap[&D];
959  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
960  DMEntry = DeclPtr;
961  emission.Address = DeclPtr;
962
963  // Emit debug info for local var declaration.
964  if (HaveInsertPoint())
965    if (CGDebugInfo *DI = getDebugInfo()) {
966      if (CGM.getCodeGenOpts().getDebugInfo()
967            >= CodeGenOptions::LimitedDebugInfo) {
968        DI->setLocation(D.getLocation());
969        DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
970      }
971    }
972
973  if (D.hasAttr<AnnotateAttr>())
974      EmitVarAnnotations(&D, emission.Address);
975
976  return emission;
977}
978
979/// Determines whether the given __block variable is potentially
980/// captured by the given expression.
981static bool isCapturedBy(const VarDecl &var, const Expr *e) {
982  // Skip the most common kinds of expressions that make
983  // hierarchy-walking expensive.
984  e = e->IgnoreParenCasts();
985
986  if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
987    const BlockDecl *block = be->getBlockDecl();
988    for (BlockDecl::capture_const_iterator i = block->capture_begin(),
989           e = block->capture_end(); i != e; ++i) {
990      if (i->getVariable() == &var)
991        return true;
992    }
993
994    // No need to walk into the subexpressions.
995    return false;
996  }
997
998  if (const StmtExpr *SE = dyn_cast<StmtExpr>(e)) {
999    const CompoundStmt *CS = SE->getSubStmt();
1000    for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
1001	   BE = CS->body_end(); BI != BE; ++BI)
1002      if (Expr *E = dyn_cast<Expr>((*BI))) {
1003        if (isCapturedBy(var, E))
1004            return true;
1005      }
1006      else if (DeclStmt *DS = dyn_cast<DeclStmt>((*BI))) {
1007          // special case declarations
1008          for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
1009               I != E; ++I) {
1010              if (VarDecl *VD = dyn_cast<VarDecl>((*I))) {
1011                Expr *Init = VD->getInit();
1012                if (Init && isCapturedBy(var, Init))
1013                  return true;
1014              }
1015          }
1016      }
1017      else
1018        // FIXME. Make safe assumption assuming arbitrary statements cause capturing.
1019        // Later, provide code to poke into statements for capture analysis.
1020        return true;
1021    return false;
1022  }
1023
1024  for (Stmt::const_child_range children = e->children(); children; ++children)
1025    if (isCapturedBy(var, cast<Expr>(*children)))
1026      return true;
1027
1028  return false;
1029}
1030
1031/// \brief Determine whether the given initializer is trivial in the sense
1032/// that it requires no code to be generated.
1033static bool isTrivialInitializer(const Expr *Init) {
1034  if (!Init)
1035    return true;
1036
1037  if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init))
1038    if (CXXConstructorDecl *Constructor = Construct->getConstructor())
1039      if (Constructor->isTrivial() &&
1040          Constructor->isDefaultConstructor() &&
1041          !Construct->requiresZeroInitialization())
1042        return true;
1043
1044  return false;
1045}
1046void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
1047  assert(emission.Variable && "emission was not valid!");
1048
1049  // If this was emitted as a global constant, we're done.
1050  if (emission.wasEmittedAsGlobal()) return;
1051
1052  const VarDecl &D = *emission.Variable;
1053  QualType type = D.getType();
1054
1055  // If this local has an initializer, emit it now.
1056  const Expr *Init = D.getInit();
1057
1058  // If we are at an unreachable point, we don't need to emit the initializer
1059  // unless it contains a label.
1060  if (!HaveInsertPoint()) {
1061    if (!Init || !ContainsLabel(Init)) return;
1062    EnsureInsertPoint();
1063  }
1064
1065  // Initialize the structure of a __block variable.
1066  if (emission.IsByRef)
1067    emitByrefStructureInit(emission);
1068
1069  if (isTrivialInitializer(Init))
1070    return;
1071
1072  CharUnits alignment = emission.Alignment;
1073
1074  // Check whether this is a byref variable that's potentially
1075  // captured and moved by its own initializer.  If so, we'll need to
1076  // emit the initializer first, then copy into the variable.
1077  bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init);
1078
1079  llvm::Value *Loc =
1080    capturedByInit ? emission.Address : emission.getObjectAddress(*this);
1081
1082  llvm::Constant *constant = 0;
1083  if (emission.IsConstantAggregate || D.isConstexpr()) {
1084    assert(!capturedByInit && "constant init contains a capturing block?");
1085    constant = CGM.EmitConstantInit(D, this);
1086  }
1087
1088  if (!constant) {
1089    LValue lv = MakeAddrLValue(Loc, type, alignment);
1090    lv.setNonGC(true);
1091    return EmitExprAsInit(Init, &D, lv, capturedByInit);
1092  }
1093
1094  if (!emission.IsConstantAggregate) {
1095    // For simple scalar/complex initialization, store the value directly.
1096    LValue lv = MakeAddrLValue(Loc, type, alignment);
1097    lv.setNonGC(true);
1098    return EmitStoreThroughLValue(RValue::get(constant), lv, true);
1099  }
1100
1101  // If this is a simple aggregate initialization, we can optimize it
1102  // in various ways.
1103  bool isVolatile = type.isVolatileQualified();
1104
1105  llvm::Value *SizeVal =
1106    llvm::ConstantInt::get(IntPtrTy,
1107                           getContext().getTypeSizeInChars(type).getQuantity());
1108
1109  llvm::Type *BP = Int8PtrTy;
1110  if (Loc->getType() != BP)
1111    Loc = Builder.CreateBitCast(Loc, BP);
1112
1113  // If the initializer is all or mostly zeros, codegen with memset then do
1114  // a few stores afterward.
1115  if (shouldUseMemSetPlusStoresToInitialize(constant,
1116                CGM.getDataLayout().getTypeAllocSize(constant->getType()))) {
1117    Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal,
1118                         alignment.getQuantity(), isVolatile);
1119    // Zero and undef don't require a stores.
1120    if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) {
1121      Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo());
1122      emitStoresForInitAfterMemset(constant, Loc, isVolatile, Builder);
1123    }
1124  } else {
1125    // Otherwise, create a temporary global with the initializer then
1126    // memcpy from the global to the alloca.
1127    std::string Name = GetStaticDeclName(*this, D, ".");
1128    llvm::GlobalVariable *GV =
1129      new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true,
1130                               llvm::GlobalValue::PrivateLinkage,
1131                               constant, Name);
1132    GV->setAlignment(alignment.getQuantity());
1133    GV->setUnnamedAddr(true);
1134
1135    llvm::Value *SrcPtr = GV;
1136    if (SrcPtr->getType() != BP)
1137      SrcPtr = Builder.CreateBitCast(SrcPtr, BP);
1138
1139    Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, alignment.getQuantity(),
1140                         isVolatile);
1141  }
1142}
1143
1144/// Emit an expression as an initializer for a variable at the given
1145/// location.  The expression is not necessarily the normal
1146/// initializer for the variable, and the address is not necessarily
1147/// its normal location.
1148///
1149/// \param init the initializing expression
1150/// \param var the variable to act as if we're initializing
1151/// \param loc the address to initialize; its type is a pointer
1152///   to the LLVM mapping of the variable's type
1153/// \param alignment the alignment of the address
1154/// \param capturedByInit true if the variable is a __block variable
1155///   whose address is potentially changed by the initializer
1156void CodeGenFunction::EmitExprAsInit(const Expr *init,
1157                                     const ValueDecl *D,
1158                                     LValue lvalue,
1159                                     bool capturedByInit) {
1160  QualType type = D->getType();
1161
1162  if (type->isReferenceType()) {
1163    RValue rvalue = EmitReferenceBindingToExpr(init, D);
1164    if (capturedByInit)
1165      drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1166    EmitStoreThroughLValue(rvalue, lvalue, true);
1167    return;
1168  }
1169  switch (getEvaluationKind(type)) {
1170  case TEK_Scalar:
1171    EmitScalarInit(init, D, lvalue, capturedByInit);
1172    return;
1173  case TEK_Complex: {
1174    ComplexPairTy complex = EmitComplexExpr(init);
1175    if (capturedByInit)
1176      drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1177    EmitStoreOfComplex(complex, lvalue, /*init*/ true);
1178    return;
1179  }
1180  case TEK_Aggregate:
1181    if (type->isAtomicType()) {
1182      EmitAtomicInit(const_cast<Expr*>(init), lvalue);
1183    } else {
1184      // TODO: how can we delay here if D is captured by its initializer?
1185      EmitAggExpr(init, AggValueSlot::forLValue(lvalue,
1186                                              AggValueSlot::IsDestructed,
1187                                         AggValueSlot::DoesNotNeedGCBarriers,
1188                                              AggValueSlot::IsNotAliased));
1189    }
1190    MaybeEmitStdInitializerListCleanup(lvalue.getAddress(), init);
1191    return;
1192  }
1193  llvm_unreachable("bad evaluation kind");
1194}
1195
1196/// Enter a destroy cleanup for the given local variable.
1197void CodeGenFunction::emitAutoVarTypeCleanup(
1198                            const CodeGenFunction::AutoVarEmission &emission,
1199                            QualType::DestructionKind dtorKind) {
1200  assert(dtorKind != QualType::DK_none);
1201
1202  // Note that for __block variables, we want to destroy the
1203  // original stack object, not the possibly forwarded object.
1204  llvm::Value *addr = emission.getObjectAddress(*this);
1205
1206  const VarDecl *var = emission.Variable;
1207  QualType type = var->getType();
1208
1209  CleanupKind cleanupKind = NormalAndEHCleanup;
1210  CodeGenFunction::Destroyer *destroyer = 0;
1211
1212  switch (dtorKind) {
1213  case QualType::DK_none:
1214    llvm_unreachable("no cleanup for trivially-destructible variable");
1215
1216  case QualType::DK_cxx_destructor:
1217    // If there's an NRVO flag on the emission, we need a different
1218    // cleanup.
1219    if (emission.NRVOFlag) {
1220      assert(!type->isArrayType());
1221      CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor();
1222      EHStack.pushCleanup<DestroyNRVOVariable>(cleanupKind, addr, dtor,
1223                                               emission.NRVOFlag);
1224      return;
1225    }
1226    break;
1227
1228  case QualType::DK_objc_strong_lifetime:
1229    // Suppress cleanups for pseudo-strong variables.
1230    if (var->isARCPseudoStrong()) return;
1231
1232    // Otherwise, consider whether to use an EH cleanup or not.
1233    cleanupKind = getARCCleanupKind();
1234
1235    // Use the imprecise destroyer by default.
1236    if (!var->hasAttr<ObjCPreciseLifetimeAttr>())
1237      destroyer = CodeGenFunction::destroyARCStrongImprecise;
1238    break;
1239
1240  case QualType::DK_objc_weak_lifetime:
1241    break;
1242  }
1243
1244  // If we haven't chosen a more specific destroyer, use the default.
1245  if (!destroyer) destroyer = getDestroyer(dtorKind);
1246
1247  // Use an EH cleanup in array destructors iff the destructor itself
1248  // is being pushed as an EH cleanup.
1249  bool useEHCleanup = (cleanupKind & EHCleanup);
1250  EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer,
1251                                     useEHCleanup);
1252}
1253
1254void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
1255  assert(emission.Variable && "emission was not valid!");
1256
1257  // If this was emitted as a global constant, we're done.
1258  if (emission.wasEmittedAsGlobal()) return;
1259
1260  // If we don't have an insertion point, we're done.  Sema prevents
1261  // us from jumping into any of these scopes anyway.
1262  if (!HaveInsertPoint()) return;
1263
1264  const VarDecl &D = *emission.Variable;
1265
1266  // Make sure we call @llvm.lifetime.end.  This needs to happen
1267  // *last*, so the cleanup needs to be pushed *first*.
1268  if (emission.useLifetimeMarkers()) {
1269    EHStack.pushCleanup<CallLifetimeEnd>(NormalCleanup,
1270                                         emission.getAllocatedAddress(),
1271                                         emission.getSizeForLifetimeMarkers());
1272  }
1273
1274  // Check the type for a cleanup.
1275  if (QualType::DestructionKind dtorKind = D.getType().isDestructedType())
1276    emitAutoVarTypeCleanup(emission, dtorKind);
1277
1278  // In GC mode, honor objc_precise_lifetime.
1279  if (getLangOpts().getGC() != LangOptions::NonGC &&
1280      D.hasAttr<ObjCPreciseLifetimeAttr>()) {
1281    EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D);
1282  }
1283
1284  // Handle the cleanup attribute.
1285  if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
1286    const FunctionDecl *FD = CA->getFunctionDecl();
1287
1288    llvm::Constant *F = CGM.GetAddrOfFunction(FD);
1289    assert(F && "Could not find function!");
1290
1291    const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD);
1292    EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D);
1293  }
1294
1295  // If this is a block variable, call _Block_object_destroy
1296  // (on the unforwarded address).
1297  if (emission.IsByRef)
1298    enterByrefCleanup(emission);
1299}
1300
1301CodeGenFunction::Destroyer *
1302CodeGenFunction::getDestroyer(QualType::DestructionKind kind) {
1303  switch (kind) {
1304  case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor");
1305  case QualType::DK_cxx_destructor:
1306    return destroyCXXObject;
1307  case QualType::DK_objc_strong_lifetime:
1308    return destroyARCStrongPrecise;
1309  case QualType::DK_objc_weak_lifetime:
1310    return destroyARCWeak;
1311  }
1312  llvm_unreachable("Unknown DestructionKind");
1313}
1314
1315/// pushEHDestroy - Push the standard destructor for the given type as
1316/// an EH-only cleanup.
1317void CodeGenFunction::pushEHDestroy(QualType::DestructionKind dtorKind,
1318                                  llvm::Value *addr, QualType type) {
1319  assert(dtorKind && "cannot push destructor for trivial type");
1320  assert(needsEHCleanup(dtorKind));
1321
1322  pushDestroy(EHCleanup, addr, type, getDestroyer(dtorKind), true);
1323}
1324
1325/// pushDestroy - Push the standard destructor for the given type as
1326/// at least a normal cleanup.
1327void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind,
1328                                  llvm::Value *addr, QualType type) {
1329  assert(dtorKind && "cannot push destructor for trivial type");
1330
1331  CleanupKind cleanupKind = getCleanupKind(dtorKind);
1332  pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind),
1333              cleanupKind & EHCleanup);
1334}
1335
1336void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, llvm::Value *addr,
1337                                  QualType type, Destroyer *destroyer,
1338                                  bool useEHCleanupForArray) {
1339  pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type,
1340                                     destroyer, useEHCleanupForArray);
1341}
1342
1343void CodeGenFunction::pushLifetimeExtendedDestroy(
1344    CleanupKind cleanupKind, llvm::Value *addr, QualType type,
1345    Destroyer *destroyer, bool useEHCleanupForArray) {
1346  assert(!isInConditionalBranch() &&
1347         "performing lifetime extension from within conditional");
1348
1349  // Push an EH-only cleanup for the object now.
1350  // FIXME: When popping normal cleanups, we need to keep this EH cleanup
1351  // around in case a temporary's destructor throws an exception.
1352  if (cleanupKind & EHCleanup)
1353    EHStack.pushCleanup<DestroyObject>(
1354        static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), addr, type,
1355        destroyer, useEHCleanupForArray);
1356
1357  // Remember that we need to push a full cleanup for the object at the
1358  // end of the full-expression.
1359  pushCleanupAfterFullExpr<DestroyObject>(
1360      cleanupKind, addr, type, destroyer, useEHCleanupForArray);
1361}
1362
1363/// emitDestroy - Immediately perform the destruction of the given
1364/// object.
1365///
1366/// \param addr - the address of the object; a type*
1367/// \param type - the type of the object; if an array type, all
1368///   objects are destroyed in reverse order
1369/// \param destroyer - the function to call to destroy individual
1370///   elements
1371/// \param useEHCleanupForArray - whether an EH cleanup should be
1372///   used when destroying array elements, in case one of the
1373///   destructions throws an exception
1374void CodeGenFunction::emitDestroy(llvm::Value *addr, QualType type,
1375                                  Destroyer *destroyer,
1376                                  bool useEHCleanupForArray) {
1377  const ArrayType *arrayType = getContext().getAsArrayType(type);
1378  if (!arrayType)
1379    return destroyer(*this, addr, type);
1380
1381  llvm::Value *begin = addr;
1382  llvm::Value *length = emitArrayLength(arrayType, type, begin);
1383
1384  // Normally we have to check whether the array is zero-length.
1385  bool checkZeroLength = true;
1386
1387  // But if the array length is constant, we can suppress that.
1388  if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) {
1389    // ...and if it's constant zero, we can just skip the entire thing.
1390    if (constLength->isZero()) return;
1391    checkZeroLength = false;
1392  }
1393
1394  llvm::Value *end = Builder.CreateInBoundsGEP(begin, length);
1395  emitArrayDestroy(begin, end, type, destroyer,
1396                   checkZeroLength, useEHCleanupForArray);
1397}
1398
1399/// emitArrayDestroy - Destroys all the elements of the given array,
1400/// beginning from last to first.  The array cannot be zero-length.
1401///
1402/// \param begin - a type* denoting the first element of the array
1403/// \param end - a type* denoting one past the end of the array
1404/// \param type - the element type of the array
1405/// \param destroyer - the function to call to destroy elements
1406/// \param useEHCleanup - whether to push an EH cleanup to destroy
1407///   the remaining elements in case the destruction of a single
1408///   element throws
1409void CodeGenFunction::emitArrayDestroy(llvm::Value *begin,
1410                                       llvm::Value *end,
1411                                       QualType type,
1412                                       Destroyer *destroyer,
1413                                       bool checkZeroLength,
1414                                       bool useEHCleanup) {
1415  assert(!type->isArrayType());
1416
1417  // The basic structure here is a do-while loop, because we don't
1418  // need to check for the zero-element case.
1419  llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body");
1420  llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done");
1421
1422  if (checkZeroLength) {
1423    llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end,
1424                                                "arraydestroy.isempty");
1425    Builder.CreateCondBr(isEmpty, doneBB, bodyBB);
1426  }
1427
1428  // Enter the loop body, making that address the current address.
1429  llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1430  EmitBlock(bodyBB);
1431  llvm::PHINode *elementPast =
1432    Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast");
1433  elementPast->addIncoming(end, entryBB);
1434
1435  // Shift the address back by one element.
1436  llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true);
1437  llvm::Value *element = Builder.CreateInBoundsGEP(elementPast, negativeOne,
1438                                                   "arraydestroy.element");
1439
1440  if (useEHCleanup)
1441    pushRegularPartialArrayCleanup(begin, element, type, destroyer);
1442
1443  // Perform the actual destruction there.
1444  destroyer(*this, element, type);
1445
1446  if (useEHCleanup)
1447    PopCleanupBlock();
1448
1449  // Check whether we've reached the end.
1450  llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done");
1451  Builder.CreateCondBr(done, doneBB, bodyBB);
1452  elementPast->addIncoming(element, Builder.GetInsertBlock());
1453
1454  // Done.
1455  EmitBlock(doneBB);
1456}
1457
1458/// Perform partial array destruction as if in an EH cleanup.  Unlike
1459/// emitArrayDestroy, the element type here may still be an array type.
1460static void emitPartialArrayDestroy(CodeGenFunction &CGF,
1461                                    llvm::Value *begin, llvm::Value *end,
1462                                    QualType type,
1463                                    CodeGenFunction::Destroyer *destroyer) {
1464  // If the element type is itself an array, drill down.
1465  unsigned arrayDepth = 0;
1466  while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) {
1467    // VLAs don't require a GEP index to walk into.
1468    if (!isa<VariableArrayType>(arrayType))
1469      arrayDepth++;
1470    type = arrayType->getElementType();
1471  }
1472
1473  if (arrayDepth) {
1474    llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, arrayDepth+1);
1475
1476    SmallVector<llvm::Value*,4> gepIndices(arrayDepth, zero);
1477    begin = CGF.Builder.CreateInBoundsGEP(begin, gepIndices, "pad.arraybegin");
1478    end = CGF.Builder.CreateInBoundsGEP(end, gepIndices, "pad.arrayend");
1479  }
1480
1481  // Destroy the array.  We don't ever need an EH cleanup because we
1482  // assume that we're in an EH cleanup ourselves, so a throwing
1483  // destructor causes an immediate terminate.
1484  CGF.emitArrayDestroy(begin, end, type, destroyer,
1485                       /*checkZeroLength*/ true, /*useEHCleanup*/ false);
1486}
1487
1488namespace {
1489  /// RegularPartialArrayDestroy - a cleanup which performs a partial
1490  /// array destroy where the end pointer is regularly determined and
1491  /// does not need to be loaded from a local.
1492  class RegularPartialArrayDestroy : public EHScopeStack::Cleanup {
1493    llvm::Value *ArrayBegin;
1494    llvm::Value *ArrayEnd;
1495    QualType ElementType;
1496    CodeGenFunction::Destroyer *Destroyer;
1497  public:
1498    RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd,
1499                               QualType elementType,
1500                               CodeGenFunction::Destroyer *destroyer)
1501      : ArrayBegin(arrayBegin), ArrayEnd(arrayEnd),
1502        ElementType(elementType), Destroyer(destroyer) {}
1503
1504    void Emit(CodeGenFunction &CGF, Flags flags) {
1505      emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd,
1506                              ElementType, Destroyer);
1507    }
1508  };
1509
1510  /// IrregularPartialArrayDestroy - a cleanup which performs a
1511  /// partial array destroy where the end pointer is irregularly
1512  /// determined and must be loaded from a local.
1513  class IrregularPartialArrayDestroy : public EHScopeStack::Cleanup {
1514    llvm::Value *ArrayBegin;
1515    llvm::Value *ArrayEndPointer;
1516    QualType ElementType;
1517    CodeGenFunction::Destroyer *Destroyer;
1518  public:
1519    IrregularPartialArrayDestroy(llvm::Value *arrayBegin,
1520                                 llvm::Value *arrayEndPointer,
1521                                 QualType elementType,
1522                                 CodeGenFunction::Destroyer *destroyer)
1523      : ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer),
1524        ElementType(elementType), Destroyer(destroyer) {}
1525
1526    void Emit(CodeGenFunction &CGF, Flags flags) {
1527      llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer);
1528      emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd,
1529                              ElementType, Destroyer);
1530    }
1531  };
1532}
1533
1534/// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy
1535/// already-constructed elements of the given array.  The cleanup
1536/// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1537///
1538/// \param elementType - the immediate element type of the array;
1539///   possibly still an array type
1540void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
1541                                                 llvm::Value *arrayEndPointer,
1542                                                       QualType elementType,
1543                                                       Destroyer *destroyer) {
1544  pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup,
1545                                                    arrayBegin, arrayEndPointer,
1546                                                    elementType, destroyer);
1547}
1548
1549/// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
1550/// already-constructed elements of the given array.  The cleanup
1551/// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1552///
1553/// \param elementType - the immediate element type of the array;
1554///   possibly still an array type
1555void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin,
1556                                                     llvm::Value *arrayEnd,
1557                                                     QualType elementType,
1558                                                     Destroyer *destroyer) {
1559  pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup,
1560                                                  arrayBegin, arrayEnd,
1561                                                  elementType, destroyer);
1562}
1563
1564/// Lazily declare the @llvm.lifetime.start intrinsic.
1565llvm::Constant *CodeGenModule::getLLVMLifetimeStartFn() {
1566  if (LifetimeStartFn) return LifetimeStartFn;
1567  LifetimeStartFn = llvm::Intrinsic::getDeclaration(&getModule(),
1568                                            llvm::Intrinsic::lifetime_start);
1569  return LifetimeStartFn;
1570}
1571
1572/// Lazily declare the @llvm.lifetime.end intrinsic.
1573llvm::Constant *CodeGenModule::getLLVMLifetimeEndFn() {
1574  if (LifetimeEndFn) return LifetimeEndFn;
1575  LifetimeEndFn = llvm::Intrinsic::getDeclaration(&getModule(),
1576                                              llvm::Intrinsic::lifetime_end);
1577  return LifetimeEndFn;
1578}
1579
1580namespace {
1581  /// A cleanup to perform a release of an object at the end of a
1582  /// function.  This is used to balance out the incoming +1 of a
1583  /// ns_consumed argument when we can't reasonably do that just by
1584  /// not doing the initial retain for a __block argument.
1585  struct ConsumeARCParameter : EHScopeStack::Cleanup {
1586    ConsumeARCParameter(llvm::Value *param,
1587                        ARCPreciseLifetime_t precise)
1588      : Param(param), Precise(precise) {}
1589
1590    llvm::Value *Param;
1591    ARCPreciseLifetime_t Precise;
1592
1593    void Emit(CodeGenFunction &CGF, Flags flags) {
1594      CGF.EmitARCRelease(Param, Precise);
1595    }
1596  };
1597}
1598
1599/// Emit an alloca (or GlobalValue depending on target)
1600/// for the specified parameter and set up LocalDeclMap.
1601void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
1602                                   unsigned ArgNo) {
1603  // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
1604  assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
1605         "Invalid argument to EmitParmDecl");
1606
1607  Arg->setName(D.getName());
1608
1609  QualType Ty = D.getType();
1610
1611  // Use better IR generation for certain implicit parameters.
1612  if (isa<ImplicitParamDecl>(D)) {
1613    // The only implicit argument a block has is its literal.
1614    if (BlockInfo) {
1615      LocalDeclMap[&D] = Arg;
1616      llvm::Value *LocalAddr = 0;
1617      if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1618        // Allocate a stack slot to let the debug info survive the RA.
1619        llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1620                                                   D.getName() + ".addr");
1621        Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity());
1622        LValue lv = MakeAddrLValue(Alloc, Ty, getContext().getDeclAlign(&D));
1623        EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1624        LocalAddr = Builder.CreateLoad(Alloc);
1625      }
1626
1627      if (CGDebugInfo *DI = getDebugInfo()) {
1628        if (CGM.getCodeGenOpts().getDebugInfo()
1629              >= CodeGenOptions::LimitedDebugInfo) {
1630          DI->setLocation(D.getLocation());
1631          DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, Arg, LocalAddr, Builder);
1632        }
1633      }
1634
1635      return;
1636    }
1637  }
1638
1639  llvm::Value *DeclPtr;
1640  // If this is an aggregate or variable sized value, reuse the input pointer.
1641  if (!Ty->isConstantSizeType() ||
1642      !CodeGenFunction::hasScalarEvaluationKind(Ty)) {
1643    DeclPtr = Arg;
1644  } else {
1645    // Otherwise, create a temporary to hold the value.
1646    llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1647                                               D.getName() + ".addr");
1648    CharUnits Align = getContext().getDeclAlign(&D);
1649    Alloc->setAlignment(Align.getQuantity());
1650    DeclPtr = Alloc;
1651
1652    bool doStore = true;
1653
1654    Qualifiers qs = Ty.getQualifiers();
1655    LValue lv = MakeAddrLValue(DeclPtr, Ty, Align);
1656    if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) {
1657      // We honor __attribute__((ns_consumed)) for types with lifetime.
1658      // For __strong, it's handled by just skipping the initial retain;
1659      // otherwise we have to balance out the initial +1 with an extra
1660      // cleanup to do the release at the end of the function.
1661      bool isConsumed = D.hasAttr<NSConsumedAttr>();
1662
1663      // 'self' is always formally __strong, but if this is not an
1664      // init method then we don't want to retain it.
1665      if (D.isARCPseudoStrong()) {
1666        const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CurCodeDecl);
1667        assert(&D == method->getSelfDecl());
1668        assert(lt == Qualifiers::OCL_Strong);
1669        assert(qs.hasConst());
1670        assert(method->getMethodFamily() != OMF_init);
1671        (void) method;
1672        lt = Qualifiers::OCL_ExplicitNone;
1673      }
1674
1675      if (lt == Qualifiers::OCL_Strong) {
1676        if (!isConsumed) {
1677          if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1678            // use objc_storeStrong(&dest, value) for retaining the
1679            // object. But first, store a null into 'dest' because
1680            // objc_storeStrong attempts to release its old value.
1681            llvm::Value * Null = CGM.EmitNullConstant(D.getType());
1682            EmitStoreOfScalar(Null, lv, /* isInitialization */ true);
1683            EmitARCStoreStrongCall(lv.getAddress(), Arg, true);
1684            doStore = false;
1685          }
1686          else
1687          // Don't use objc_retainBlock for block pointers, because we
1688          // don't want to Block_copy something just because we got it
1689          // as a parameter.
1690            Arg = EmitARCRetainNonBlock(Arg);
1691        }
1692      } else {
1693        // Push the cleanup for a consumed parameter.
1694        if (isConsumed) {
1695          ARCPreciseLifetime_t precise = (D.hasAttr<ObjCPreciseLifetimeAttr>()
1696                                ? ARCPreciseLifetime : ARCImpreciseLifetime);
1697          EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), Arg,
1698                                                   precise);
1699        }
1700
1701        if (lt == Qualifiers::OCL_Weak) {
1702          EmitARCInitWeak(DeclPtr, Arg);
1703          doStore = false; // The weak init is a store, no need to do two.
1704        }
1705      }
1706
1707      // Enter the cleanup scope.
1708      EmitAutoVarWithLifetime(*this, D, DeclPtr, lt);
1709    }
1710
1711    // Store the initial value into the alloca.
1712    if (doStore)
1713      EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1714  }
1715
1716  llvm::Value *&DMEntry = LocalDeclMap[&D];
1717  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
1718  DMEntry = DeclPtr;
1719
1720  // Emit debug info for param declaration.
1721  if (CGDebugInfo *DI = getDebugInfo()) {
1722    if (CGM.getCodeGenOpts().getDebugInfo()
1723          >= CodeGenOptions::LimitedDebugInfo) {
1724      DI->EmitDeclareOfArgVariable(&D, DeclPtr, ArgNo, Builder);
1725    }
1726  }
1727
1728  if (D.hasAttr<AnnotateAttr>())
1729      EmitVarAnnotations(&D, DeclPtr);
1730}
1731