CGDecl.cpp revision 93cc515d3b99dca18d287d200e19355a2e9c02b2 
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.
130    if (D.isExternallyVisible()) {
131      const Decl *D = CurCodeDecl;
132      while (true) {
133        if (isa<BlockDecl>(D)) {
134          // FIXME: Handle this case properly!  (Should be similar to the
135          // way we handle lambdas in computeLVForDecl in Decl.cpp.)
136          break;
137        } else if (isa<CapturedDecl>(D)) {
138          D = cast<Decl>(cast<CapturedDecl>(D)->getParent());
139        } else {
140          break;
141        }
142      }
143      // FIXME: Do we really only care about FunctionDecls here?
144      if (isa<FunctionDecl>(D)) {
145        llvm::GlobalValue::LinkageTypes ParentLinkage =
146            CGM.getFunctionLinkage(cast<FunctionDecl>(D));
147        if (llvm::GlobalValue::isWeakForLinker(ParentLinkage))
148          Linkage = ParentLinkage;
149      }
150    }
151
152    return EmitStaticVarDecl(D, Linkage);
153  }
154
155  if (D.hasExternalStorage())
156    // Don't emit it now, allow it to be emitted lazily on its first use.
157    return;
158
159  if (D.getStorageClass() == SC_OpenCLWorkGroupLocal)
160    return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D);
161
162  assert(D.hasLocalStorage());
163  return EmitAutoVarDecl(D);
164}
165
166static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D,
167                                     const char *Separator) {
168  CodeGenModule &CGM = CGF.CGM;
169  if (CGF.getLangOpts().CPlusPlus) {
170    StringRef Name = CGM.getMangledName(&D);
171    return Name.str();
172  }
173
174  std::string ContextName;
175  if (!CGF.CurFuncDecl) {
176    // Better be in a block declared in global scope.
177    const NamedDecl *ND = cast<NamedDecl>(&D);
178    const DeclContext *DC = ND->getDeclContext();
179    if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) {
180      MangleBuffer Name;
181      CGM.getBlockMangledName(GlobalDecl(), Name, BD);
182      ContextName = Name.getString();
183    }
184    else
185      llvm_unreachable("Unknown context for block static var decl");
186  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl)) {
187    StringRef Name = CGM.getMangledName(FD);
188    ContextName = Name.str();
189  } else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl))
190    ContextName = CGF.CurFn->getName();
191  else
192    llvm_unreachable("Unknown context for static var decl");
193
194  return ContextName + Separator + D.getNameAsString();
195}
196
197llvm::GlobalVariable *
198CodeGenFunction::CreateStaticVarDecl(const VarDecl &D,
199                                     const char *Separator,
200                                     llvm::GlobalValue::LinkageTypes Linkage) {
201  QualType Ty = D.getType();
202  assert(Ty->isConstantSizeType() && "VLAs can't be static");
203
204  // Use the label if the variable is renamed with the asm-label extension.
205  std::string Name;
206  if (D.hasAttr<AsmLabelAttr>())
207    Name = CGM.getMangledName(&D);
208  else
209    Name = GetStaticDeclName(*this, D, Separator);
210
211  llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty);
212  unsigned AddrSpace =
213   CGM.GetGlobalVarAddressSpace(&D, CGM.getContext().getTargetAddressSpace(Ty));
214  llvm::GlobalVariable *GV =
215    new llvm::GlobalVariable(CGM.getModule(), LTy,
216                             Ty.isConstant(getContext()), Linkage,
217                             CGM.EmitNullConstant(D.getType()), Name, 0,
218                             llvm::GlobalVariable::NotThreadLocal,
219                             AddrSpace);
220  GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
221  CGM.setGlobalVisibility(GV, &D);
222
223  if (D.getTLSKind())
224    CGM.setTLSMode(GV, D);
225
226  return GV;
227}
228
229/// hasNontrivialDestruction - Determine whether a type's destruction is
230/// non-trivial. If so, and the variable uses static initialization, we must
231/// register its destructor to run on exit.
232static bool hasNontrivialDestruction(QualType T) {
233  CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
234  return RD && !RD->hasTrivialDestructor();
235}
236
237/// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the
238/// global variable that has already been created for it.  If the initializer
239/// has a different type than GV does, this may free GV and return a different
240/// one.  Otherwise it just returns GV.
241llvm::GlobalVariable *
242CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
243                                               llvm::GlobalVariable *GV) {
244  llvm::Constant *Init = CGM.EmitConstantInit(D, this);
245
246  // If constant emission failed, then this should be a C++ static
247  // initializer.
248  if (!Init) {
249    if (!getLangOpts().CPlusPlus)
250      CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
251    else if (Builder.GetInsertBlock()) {
252      // Since we have a static initializer, this global variable can't
253      // be constant.
254      GV->setConstant(false);
255
256      EmitCXXGuardedInit(D, GV, /*PerformInit*/true);
257    }
258    return GV;
259  }
260
261  // The initializer may differ in type from the global. Rewrite
262  // the global to match the initializer.  (We have to do this
263  // because some types, like unions, can't be completely represented
264  // in the LLVM type system.)
265  if (GV->getType()->getElementType() != Init->getType()) {
266    llvm::GlobalVariable *OldGV = GV;
267
268    GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
269                                  OldGV->isConstant(),
270                                  OldGV->getLinkage(), Init, "",
271                                  /*InsertBefore*/ OldGV,
272                                  OldGV->getThreadLocalMode(),
273                           CGM.getContext().getTargetAddressSpace(D.getType()));
274    GV->setVisibility(OldGV->getVisibility());
275
276    // Steal the name of the old global
277    GV->takeName(OldGV);
278
279    // Replace all uses of the old global with the new global
280    llvm::Constant *NewPtrForOldDecl =
281    llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
282    OldGV->replaceAllUsesWith(NewPtrForOldDecl);
283
284    // Erase the old global, since it is no longer used.
285    OldGV->eraseFromParent();
286  }
287
288  GV->setConstant(CGM.isTypeConstant(D.getType(), true));
289  GV->setInitializer(Init);
290
291  if (hasNontrivialDestruction(D.getType())) {
292    // We have a constant initializer, but a nontrivial destructor. We still
293    // need to perform a guarded "initialization" in order to register the
294    // destructor.
295    EmitCXXGuardedInit(D, GV, /*PerformInit*/false);
296  }
297
298  return GV;
299}
300
301void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
302                                      llvm::GlobalValue::LinkageTypes Linkage) {
303  llvm::Value *&DMEntry = LocalDeclMap[&D];
304  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
305
306  // Check to see if we already have a global variable for this
307  // declaration.  This can happen when double-emitting function
308  // bodies, e.g. with complete and base constructors.
309  llvm::Constant *addr =
310    CGM.getStaticLocalDeclAddress(&D);
311
312  llvm::GlobalVariable *var;
313  if (addr) {
314    var = cast<llvm::GlobalVariable>(addr->stripPointerCasts());
315  } else {
316    addr = var = CreateStaticVarDecl(D, ".", Linkage);
317  }
318
319  // Store into LocalDeclMap before generating initializer to handle
320  // circular references.
321  DMEntry = addr;
322  CGM.setStaticLocalDeclAddress(&D, addr);
323
324  // We can't have a VLA here, but we can have a pointer to a VLA,
325  // even though that doesn't really make any sense.
326  // Make sure to evaluate VLA bounds now so that we have them for later.
327  if (D.getType()->isVariablyModifiedType())
328    EmitVariablyModifiedType(D.getType());
329
330  // Save the type in case adding the initializer forces a type change.
331  llvm::Type *expectedType = addr->getType();
332
333  // If this value has an initializer, emit it.
334  if (D.getInit())
335    var = AddInitializerToStaticVarDecl(D, var);
336
337  var->setAlignment(getContext().getDeclAlign(&D).getQuantity());
338
339  if (D.hasAttr<AnnotateAttr>())
340    CGM.AddGlobalAnnotations(&D, var);
341
342  if (const SectionAttr *SA = D.getAttr<SectionAttr>())
343    var->setSection(SA->getName());
344
345  if (D.hasAttr<UsedAttr>())
346    CGM.AddUsedGlobal(var);
347
348  // We may have to cast the constant because of the initializer
349  // mismatch above.
350  //
351  // FIXME: It is really dangerous to store this in the map; if anyone
352  // RAUW's the GV uses of this constant will be invalid.
353  llvm::Constant *castedAddr = llvm::ConstantExpr::getBitCast(var, expectedType);
354  DMEntry = castedAddr;
355  CGM.setStaticLocalDeclAddress(&D, castedAddr);
356
357  // Emit global variable debug descriptor for static vars.
358  CGDebugInfo *DI = getDebugInfo();
359  if (DI &&
360      CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) {
361    DI->setLocation(D.getLocation());
362    DI->EmitGlobalVariable(var, &D);
363  }
364}
365
366namespace {
367  struct DestroyObject : EHScopeStack::Cleanup {
368    DestroyObject(llvm::Value *addr, QualType type,
369                  CodeGenFunction::Destroyer *destroyer,
370                  bool useEHCleanupForArray)
371      : addr(addr), type(type), destroyer(destroyer),
372        useEHCleanupForArray(useEHCleanupForArray) {}
373
374    llvm::Value *addr;
375    QualType type;
376    CodeGenFunction::Destroyer *destroyer;
377    bool useEHCleanupForArray;
378
379    void Emit(CodeGenFunction &CGF, Flags flags) {
380      // Don't use an EH cleanup recursively from an EH cleanup.
381      bool useEHCleanupForArray =
382        flags.isForNormalCleanup() && this->useEHCleanupForArray;
383
384      CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray);
385    }
386  };
387
388  struct DestroyNRVOVariable : EHScopeStack::Cleanup {
389    DestroyNRVOVariable(llvm::Value *addr,
390                        const CXXDestructorDecl *Dtor,
391                        llvm::Value *NRVOFlag)
392      : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(addr) {}
393
394    const CXXDestructorDecl *Dtor;
395    llvm::Value *NRVOFlag;
396    llvm::Value *Loc;
397
398    void Emit(CodeGenFunction &CGF, Flags flags) {
399      // Along the exceptions path we always execute the dtor.
400      bool NRVO = flags.isForNormalCleanup() && NRVOFlag;
401
402      llvm::BasicBlock *SkipDtorBB = 0;
403      if (NRVO) {
404        // If we exited via NRVO, we skip the destructor call.
405        llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused");
406        SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor");
407        llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val");
408        CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB);
409        CGF.EmitBlock(RunDtorBB);
410      }
411
412      CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
413                                /*ForVirtualBase=*/false,
414                                /*Delegating=*/false,
415                                Loc);
416
417      if (NRVO) CGF.EmitBlock(SkipDtorBB);
418    }
419  };
420
421  struct CallStackRestore : EHScopeStack::Cleanup {
422    llvm::Value *Stack;
423    CallStackRestore(llvm::Value *Stack) : Stack(Stack) {}
424    void Emit(CodeGenFunction &CGF, Flags flags) {
425      llvm::Value *V = CGF.Builder.CreateLoad(Stack);
426      llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
427      CGF.Builder.CreateCall(F, V);
428    }
429  };
430
431  struct ExtendGCLifetime : EHScopeStack::Cleanup {
432    const VarDecl &Var;
433    ExtendGCLifetime(const VarDecl *var) : Var(*var) {}
434
435    void Emit(CodeGenFunction &CGF, Flags flags) {
436      // Compute the address of the local variable, in case it's a
437      // byref or something.
438      DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
439                      Var.getType(), VK_LValue, SourceLocation());
440      llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE));
441      CGF.EmitExtendGCLifetime(value);
442    }
443  };
444
445  struct CallCleanupFunction : EHScopeStack::Cleanup {
446    llvm::Constant *CleanupFn;
447    const CGFunctionInfo &FnInfo;
448    const VarDecl &Var;
449
450    CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
451                        const VarDecl *Var)
452      : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {}
453
454    void Emit(CodeGenFunction &CGF, Flags flags) {
455      DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
456                      Var.getType(), VK_LValue, SourceLocation());
457      // Compute the address of the local variable, in case it's a byref
458      // or something.
459      llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getAddress();
460
461      // In some cases, the type of the function argument will be different from
462      // the type of the pointer. An example of this is
463      // void f(void* arg);
464      // __attribute__((cleanup(f))) void *g;
465      //
466      // To fix this we insert a bitcast here.
467      QualType ArgTy = FnInfo.arg_begin()->type;
468      llvm::Value *Arg =
469        CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy));
470
471      CallArgList Args;
472      Args.add(RValue::get(Arg),
473               CGF.getContext().getPointerType(Var.getType()));
474      CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args);
475    }
476  };
477
478  /// A cleanup to call @llvm.lifetime.end.
479  class CallLifetimeEnd : public EHScopeStack::Cleanup {
480    llvm::Value *Addr;
481    llvm::Value *Size;
482  public:
483    CallLifetimeEnd(llvm::Value *addr, llvm::Value *size)
484      : Addr(addr), Size(size) {}
485
486    void Emit(CodeGenFunction &CGF, Flags flags) {
487      llvm::Value *castAddr = CGF.Builder.CreateBitCast(Addr, CGF.Int8PtrTy);
488      CGF.Builder.CreateCall2(CGF.CGM.getLLVMLifetimeEndFn(),
489                              Size, castAddr)
490        ->setDoesNotThrow();
491    }
492  };
493}
494
495/// EmitAutoVarWithLifetime - Does the setup required for an automatic
496/// variable with lifetime.
497static void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var,
498                                    llvm::Value *addr,
499                                    Qualifiers::ObjCLifetime lifetime) {
500  switch (lifetime) {
501  case Qualifiers::OCL_None:
502    llvm_unreachable("present but none");
503
504  case Qualifiers::OCL_ExplicitNone:
505    // nothing to do
506    break;
507
508  case Qualifiers::OCL_Strong: {
509    CodeGenFunction::Destroyer *destroyer =
510      (var.hasAttr<ObjCPreciseLifetimeAttr>()
511       ? CodeGenFunction::destroyARCStrongPrecise
512       : CodeGenFunction::destroyARCStrongImprecise);
513
514    CleanupKind cleanupKind = CGF.getARCCleanupKind();
515    CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer,
516                    cleanupKind & EHCleanup);
517    break;
518  }
519  case Qualifiers::OCL_Autoreleasing:
520    // nothing to do
521    break;
522
523  case Qualifiers::OCL_Weak:
524    // __weak objects always get EH cleanups; otherwise, exceptions
525    // could cause really nasty crashes instead of mere leaks.
526    CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(),
527                    CodeGenFunction::destroyARCWeak,
528                    /*useEHCleanup*/ true);
529    break;
530  }
531}
532
533static bool isAccessedBy(const VarDecl &var, const Stmt *s) {
534  if (const Expr *e = dyn_cast<Expr>(s)) {
535    // Skip the most common kinds of expressions that make
536    // hierarchy-walking expensive.
537    s = e = e->IgnoreParenCasts();
538
539    if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e))
540      return (ref->getDecl() == &var);
541    if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
542      const BlockDecl *block = be->getBlockDecl();
543      for (BlockDecl::capture_const_iterator i = block->capture_begin(),
544           e = block->capture_end(); i != e; ++i) {
545        if (i->getVariable() == &var)
546          return true;
547      }
548    }
549  }
550
551  for (Stmt::const_child_range children = s->children(); children; ++children)
552    // children might be null; as in missing decl or conditional of an if-stmt.
553    if ((*children) && isAccessedBy(var, *children))
554      return true;
555
556  return false;
557}
558
559static bool isAccessedBy(const ValueDecl *decl, const Expr *e) {
560  if (!decl) return false;
561  if (!isa<VarDecl>(decl)) return false;
562  const VarDecl *var = cast<VarDecl>(decl);
563  return isAccessedBy(*var, e);
564}
565
566static void drillIntoBlockVariable(CodeGenFunction &CGF,
567                                   LValue &lvalue,
568                                   const VarDecl *var) {
569  lvalue.setAddress(CGF.BuildBlockByrefAddress(lvalue.getAddress(), var));
570}
571
572void CodeGenFunction::EmitScalarInit(const Expr *init,
573                                     const ValueDecl *D,
574                                     LValue lvalue,
575                                     bool capturedByInit) {
576  Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
577  if (!lifetime) {
578    llvm::Value *value = EmitScalarExpr(init);
579    if (capturedByInit)
580      drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
581    EmitStoreThroughLValue(RValue::get(value), lvalue, true);
582    return;
583  }
584
585  // If we're emitting a value with lifetime, we have to do the
586  // initialization *before* we leave the cleanup scopes.
587  if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) {
588    enterFullExpression(ewc);
589    init = ewc->getSubExpr();
590  }
591  CodeGenFunction::RunCleanupsScope Scope(*this);
592
593  // We have to maintain the illusion that the variable is
594  // zero-initialized.  If the variable might be accessed in its
595  // initializer, zero-initialize before running the initializer, then
596  // actually perform the initialization with an assign.
597  bool accessedByInit = false;
598  if (lifetime != Qualifiers::OCL_ExplicitNone)
599    accessedByInit = (capturedByInit || isAccessedBy(D, init));
600  if (accessedByInit) {
601    LValue tempLV = lvalue;
602    // Drill down to the __block object if necessary.
603    if (capturedByInit) {
604      // We can use a simple GEP for this because it can't have been
605      // moved yet.
606      tempLV.setAddress(Builder.CreateStructGEP(tempLV.getAddress(),
607                                   getByRefValueLLVMField(cast<VarDecl>(D))));
608    }
609
610    llvm::PointerType *ty
611      = cast<llvm::PointerType>(tempLV.getAddress()->getType());
612    ty = cast<llvm::PointerType>(ty->getElementType());
613
614    llvm::Value *zero = llvm::ConstantPointerNull::get(ty);
615
616    // If __weak, we want to use a barrier under certain conditions.
617    if (lifetime == Qualifiers::OCL_Weak)
618      EmitARCInitWeak(tempLV.getAddress(), zero);
619
620    // Otherwise just do a simple store.
621    else
622      EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true);
623  }
624
625  // Emit the initializer.
626  llvm::Value *value = 0;
627
628  switch (lifetime) {
629  case Qualifiers::OCL_None:
630    llvm_unreachable("present but none");
631
632  case Qualifiers::OCL_ExplicitNone:
633    // nothing to do
634    value = EmitScalarExpr(init);
635    break;
636
637  case Qualifiers::OCL_Strong: {
638    value = EmitARCRetainScalarExpr(init);
639    break;
640  }
641
642  case Qualifiers::OCL_Weak: {
643    // No way to optimize a producing initializer into this.  It's not
644    // worth optimizing for, because the value will immediately
645    // disappear in the common case.
646    value = EmitScalarExpr(init);
647
648    if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
649    if (accessedByInit)
650      EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true);
651    else
652      EmitARCInitWeak(lvalue.getAddress(), value);
653    return;
654  }
655
656  case Qualifiers::OCL_Autoreleasing:
657    value = EmitARCRetainAutoreleaseScalarExpr(init);
658    break;
659  }
660
661  if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
662
663  // If the variable might have been accessed by its initializer, we
664  // might have to initialize with a barrier.  We have to do this for
665  // both __weak and __strong, but __weak got filtered out above.
666  if (accessedByInit && lifetime == Qualifiers::OCL_Strong) {
667    llvm::Value *oldValue = EmitLoadOfScalar(lvalue);
668    EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
669    EmitARCRelease(oldValue, ARCImpreciseLifetime);
670    return;
671  }
672
673  EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
674}
675
676/// EmitScalarInit - Initialize the given lvalue with the given object.
677void CodeGenFunction::EmitScalarInit(llvm::Value *init, LValue lvalue) {
678  Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
679  if (!lifetime)
680    return EmitStoreThroughLValue(RValue::get(init), lvalue, true);
681
682  switch (lifetime) {
683  case Qualifiers::OCL_None:
684    llvm_unreachable("present but none");
685
686  case Qualifiers::OCL_ExplicitNone:
687    // nothing to do
688    break;
689
690  case Qualifiers::OCL_Strong:
691    init = EmitARCRetain(lvalue.getType(), init);
692    break;
693
694  case Qualifiers::OCL_Weak:
695    // Initialize and then skip the primitive store.
696    EmitARCInitWeak(lvalue.getAddress(), init);
697    return;
698
699  case Qualifiers::OCL_Autoreleasing:
700    init = EmitARCRetainAutorelease(lvalue.getType(), init);
701    break;
702  }
703
704  EmitStoreOfScalar(init, lvalue, /* isInitialization */ true);
705}
706
707/// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the
708/// non-zero parts of the specified initializer with equal or fewer than
709/// NumStores scalar stores.
710static bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init,
711                                                unsigned &NumStores) {
712  // Zero and Undef never requires any extra stores.
713  if (isa<llvm::ConstantAggregateZero>(Init) ||
714      isa<llvm::ConstantPointerNull>(Init) ||
715      isa<llvm::UndefValue>(Init))
716    return true;
717  if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
718      isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
719      isa<llvm::ConstantExpr>(Init))
720    return Init->isNullValue() || NumStores--;
721
722  // See if we can emit each element.
723  if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) {
724    for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
725      llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
726      if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
727        return false;
728    }
729    return true;
730  }
731
732  if (llvm::ConstantDataSequential *CDS =
733        dyn_cast<llvm::ConstantDataSequential>(Init)) {
734    for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
735      llvm::Constant *Elt = CDS->getElementAsConstant(i);
736      if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
737        return false;
738    }
739    return true;
740  }
741
742  // Anything else is hard and scary.
743  return false;
744}
745
746/// emitStoresForInitAfterMemset - For inits that
747/// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar
748/// stores that would be required.
749static void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc,
750                                         bool isVolatile, CGBuilderTy &Builder) {
751  assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) &&
752         "called emitStoresForInitAfterMemset for zero or undef value.");
753
754  if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
755      isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
756      isa<llvm::ConstantExpr>(Init)) {
757    Builder.CreateStore(Init, Loc, isVolatile);
758    return;
759  }
760
761  if (llvm::ConstantDataSequential *CDS =
762        dyn_cast<llvm::ConstantDataSequential>(Init)) {
763    for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
764      llvm::Constant *Elt = CDS->getElementAsConstant(i);
765
766      // If necessary, get a pointer to the element and emit it.
767      if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
768        emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
769                                     isVolatile, Builder);
770    }
771    return;
772  }
773
774  assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) &&
775         "Unknown value type!");
776
777  for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
778    llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
779
780    // If necessary, get a pointer to the element and emit it.
781    if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
782      emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
783                                   isVolatile, Builder);
784  }
785}
786
787
788/// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset
789/// plus some stores to initialize a local variable instead of using a memcpy
790/// from a constant global.  It is beneficial to use memset if the global is all
791/// zeros, or mostly zeros and large.
792static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init,
793                                                  uint64_t GlobalSize) {
794  // If a global is all zeros, always use a memset.
795  if (isa<llvm::ConstantAggregateZero>(Init)) return true;
796
797  // If a non-zero global is <= 32 bytes, always use a memcpy.  If it is large,
798  // do it if it will require 6 or fewer scalar stores.
799  // TODO: Should budget depends on the size?  Avoiding a large global warrants
800  // plopping in more stores.
801  unsigned StoreBudget = 6;
802  uint64_t SizeLimit = 32;
803
804  return GlobalSize > SizeLimit &&
805         canEmitInitWithFewStoresAfterMemset(Init, StoreBudget);
806}
807
808/// Should we use the LLVM lifetime intrinsics for the given local variable?
809static bool shouldUseLifetimeMarkers(CodeGenFunction &CGF, const VarDecl &D,
810                                     unsigned Size) {
811  // Always emit lifetime markers in -fsanitize=use-after-scope mode.
812  if (CGF.getLangOpts().Sanitize.UseAfterScope)
813    return true;
814  // For now, only in optimized builds.
815  if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0)
816    return false;
817
818  // Limit the size of marked objects to 32 bytes. We don't want to increase
819  // compile time by marking tiny objects.
820  unsigned SizeThreshold = 32;
821
822  return Size > SizeThreshold;
823}
824
825
826/// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a
827/// variable declaration with auto, register, or no storage class specifier.
828/// These turn into simple stack objects, or GlobalValues depending on target.
829void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
830  AutoVarEmission emission = EmitAutoVarAlloca(D);
831  EmitAutoVarInit(emission);
832  EmitAutoVarCleanups(emission);
833}
834
835/// EmitAutoVarAlloca - Emit the alloca and debug information for a
836/// local variable.  Does not emit initalization or destruction.
837CodeGenFunction::AutoVarEmission
838CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
839  QualType Ty = D.getType();
840
841  AutoVarEmission emission(D);
842
843  bool isByRef = D.hasAttr<BlocksAttr>();
844  emission.IsByRef = isByRef;
845
846  CharUnits alignment = getContext().getDeclAlign(&D);
847  emission.Alignment = alignment;
848
849  // If the type is variably-modified, emit all the VLA sizes for it.
850  if (Ty->isVariablyModifiedType())
851    EmitVariablyModifiedType(Ty);
852
853  llvm::Value *DeclPtr;
854  if (Ty->isConstantSizeType()) {
855    bool NRVO = getLangOpts().ElideConstructors &&
856      D.isNRVOVariable();
857
858    // If this value is an array or struct with a statically determinable
859    // constant initializer, there are optimizations we can do.
860    //
861    // TODO: We should constant-evaluate the initializer of any variable,
862    // as long as it is initialized by a constant expression. Currently,
863    // isConstantInitializer produces wrong answers for structs with
864    // reference or bitfield members, and a few other cases, and checking
865    // for POD-ness protects us from some of these.
866    if (D.getInit() && (Ty->isArrayType() || Ty->isRecordType()) &&
867        (D.isConstexpr() ||
868         ((Ty.isPODType(getContext()) ||
869           getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) &&
870          D.getInit()->isConstantInitializer(getContext(), false)))) {
871
872      // If the variable's a const type, and it's neither an NRVO
873      // candidate nor a __block variable and has no mutable members,
874      // emit it as a global instead.
875      if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef &&
876          CGM.isTypeConstant(Ty, true)) {
877        EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
878
879        emission.Address = 0; // signal this condition to later callbacks
880        assert(emission.wasEmittedAsGlobal());
881        return emission;
882      }
883
884      // Otherwise, tell the initialization code that we're in this case.
885      emission.IsConstantAggregate = true;
886    }
887
888    // A normal fixed sized variable becomes an alloca in the entry block,
889    // unless it's an NRVO variable.
890    llvm::Type *LTy = ConvertTypeForMem(Ty);
891
892    if (NRVO) {
893      // The named return value optimization: allocate this variable in the
894      // return slot, so that we can elide the copy when returning this
895      // variable (C++0x [class.copy]p34).
896      DeclPtr = ReturnValue;
897
898      if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
899        if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) {
900          // Create a flag that is used to indicate when the NRVO was applied
901          // to this variable. Set it to zero to indicate that NRVO was not
902          // applied.
903          llvm::Value *Zero = Builder.getFalse();
904          llvm::Value *NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo");
905          EnsureInsertPoint();
906          Builder.CreateStore(Zero, NRVOFlag);
907
908          // Record the NRVO flag for this variable.
909          NRVOFlags[&D] = NRVOFlag;
910          emission.NRVOFlag = NRVOFlag;
911        }
912      }
913    } else {
914      if (isByRef)
915        LTy = BuildByRefType(&D);
916
917      llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
918      Alloc->setName(D.getName());
919
920      CharUnits allocaAlignment = alignment;
921      if (isByRef)
922        allocaAlignment = std::max(allocaAlignment,
923            getContext().toCharUnitsFromBits(getTarget().getPointerAlign(0)));
924      Alloc->setAlignment(allocaAlignment.getQuantity());
925      DeclPtr = Alloc;
926
927      // Emit a lifetime intrinsic if meaningful.  There's no point
928      // in doing this if we don't have a valid insertion point (?).
929      uint64_t size = CGM.getDataLayout().getTypeAllocSize(LTy);
930      if (HaveInsertPoint() && shouldUseLifetimeMarkers(*this, D, size)) {
931        llvm::Value *sizeV = llvm::ConstantInt::get(Int64Ty, size);
932
933        emission.SizeForLifetimeMarkers = sizeV;
934        llvm::Value *castAddr = Builder.CreateBitCast(Alloc, Int8PtrTy);
935        Builder.CreateCall2(CGM.getLLVMLifetimeStartFn(), sizeV, castAddr)
936          ->setDoesNotThrow();
937      } else {
938        assert(!emission.useLifetimeMarkers());
939      }
940    }
941  } else {
942    EnsureInsertPoint();
943
944    if (!DidCallStackSave) {
945      // Save the stack.
946      llvm::Value *Stack = CreateTempAlloca(Int8PtrTy, "saved_stack");
947
948      llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
949      llvm::Value *V = Builder.CreateCall(F);
950
951      Builder.CreateStore(V, Stack);
952
953      DidCallStackSave = true;
954
955      // Push a cleanup block and restore the stack there.
956      // FIXME: in general circumstances, this should be an EH cleanup.
957      EHStack.pushCleanup<CallStackRestore>(NormalCleanup, Stack);
958    }
959
960    llvm::Value *elementCount;
961    QualType elementType;
962    llvm::tie(elementCount, elementType) = getVLASize(Ty);
963
964    llvm::Type *llvmTy = ConvertTypeForMem(elementType);
965
966    // Allocate memory for the array.
967    llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla");
968    vla->setAlignment(alignment.getQuantity());
969
970    DeclPtr = vla;
971  }
972
973  llvm::Value *&DMEntry = LocalDeclMap[&D];
974  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
975  DMEntry = DeclPtr;
976  emission.Address = DeclPtr;
977
978  // Emit debug info for local var declaration.
979  if (HaveInsertPoint())
980    if (CGDebugInfo *DI = getDebugInfo()) {
981      if (CGM.getCodeGenOpts().getDebugInfo()
982            >= CodeGenOptions::LimitedDebugInfo) {
983        DI->setLocation(D.getLocation());
984        DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
985      }
986    }
987
988  if (D.hasAttr<AnnotateAttr>())
989      EmitVarAnnotations(&D, emission.Address);
990
991  return emission;
992}
993
994/// Determines whether the given __block variable is potentially
995/// captured by the given expression.
996static bool isCapturedBy(const VarDecl &var, const Expr *e) {
997  // Skip the most common kinds of expressions that make
998  // hierarchy-walking expensive.
999  e = e->IgnoreParenCasts();
1000
1001  if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
1002    const BlockDecl *block = be->getBlockDecl();
1003    for (BlockDecl::capture_const_iterator i = block->capture_begin(),
1004           e = block->capture_end(); i != e; ++i) {
1005      if (i->getVariable() == &var)
1006        return true;
1007    }
1008
1009    // No need to walk into the subexpressions.
1010    return false;
1011  }
1012
1013  if (const StmtExpr *SE = dyn_cast<StmtExpr>(e)) {
1014    const CompoundStmt *CS = SE->getSubStmt();
1015    for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
1016	   BE = CS->body_end(); BI != BE; ++BI)
1017      if (Expr *E = dyn_cast<Expr>((*BI))) {
1018        if (isCapturedBy(var, E))
1019            return true;
1020      }
1021      else if (DeclStmt *DS = dyn_cast<DeclStmt>((*BI))) {
1022          // special case declarations
1023          for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
1024               I != E; ++I) {
1025              if (VarDecl *VD = dyn_cast<VarDecl>((*I))) {
1026                Expr *Init = VD->getInit();
1027                if (Init && isCapturedBy(var, Init))
1028                  return true;
1029              }
1030          }
1031      }
1032      else
1033        // FIXME. Make safe assumption assuming arbitrary statements cause capturing.
1034        // Later, provide code to poke into statements for capture analysis.
1035        return true;
1036    return false;
1037  }
1038
1039  for (Stmt::const_child_range children = e->children(); children; ++children)
1040    if (isCapturedBy(var, cast<Expr>(*children)))
1041      return true;
1042
1043  return false;
1044}
1045
1046/// \brief Determine whether the given initializer is trivial in the sense
1047/// that it requires no code to be generated.
1048static bool isTrivialInitializer(const Expr *Init) {
1049  if (!Init)
1050    return true;
1051
1052  if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init))
1053    if (CXXConstructorDecl *Constructor = Construct->getConstructor())
1054      if (Constructor->isTrivial() &&
1055          Constructor->isDefaultConstructor() &&
1056          !Construct->requiresZeroInitialization())
1057        return true;
1058
1059  return false;
1060}
1061void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
1062  assert(emission.Variable && "emission was not valid!");
1063
1064  // If this was emitted as a global constant, we're done.
1065  if (emission.wasEmittedAsGlobal()) return;
1066
1067  const VarDecl &D = *emission.Variable;
1068  QualType type = D.getType();
1069
1070  // If this local has an initializer, emit it now.
1071  const Expr *Init = D.getInit();
1072
1073  // If we are at an unreachable point, we don't need to emit the initializer
1074  // unless it contains a label.
1075  if (!HaveInsertPoint()) {
1076    if (!Init || !ContainsLabel(Init)) return;
1077    EnsureInsertPoint();
1078  }
1079
1080  // Initialize the structure of a __block variable.
1081  if (emission.IsByRef)
1082    emitByrefStructureInit(emission);
1083
1084  if (isTrivialInitializer(Init))
1085    return;
1086
1087  CharUnits alignment = emission.Alignment;
1088
1089  // Check whether this is a byref variable that's potentially
1090  // captured and moved by its own initializer.  If so, we'll need to
1091  // emit the initializer first, then copy into the variable.
1092  bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init);
1093
1094  llvm::Value *Loc =
1095    capturedByInit ? emission.Address : emission.getObjectAddress(*this);
1096
1097  llvm::Constant *constant = 0;
1098  if (emission.IsConstantAggregate || D.isConstexpr()) {
1099    assert(!capturedByInit && "constant init contains a capturing block?");
1100    constant = CGM.EmitConstantInit(D, this);
1101  }
1102
1103  if (!constant) {
1104    LValue lv = MakeAddrLValue(Loc, type, alignment);
1105    lv.setNonGC(true);
1106    return EmitExprAsInit(Init, &D, lv, capturedByInit);
1107  }
1108
1109  if (!emission.IsConstantAggregate) {
1110    // For simple scalar/complex initialization, store the value directly.
1111    LValue lv = MakeAddrLValue(Loc, type, alignment);
1112    lv.setNonGC(true);
1113    return EmitStoreThroughLValue(RValue::get(constant), lv, true);
1114  }
1115
1116  // If this is a simple aggregate initialization, we can optimize it
1117  // in various ways.
1118  bool isVolatile = type.isVolatileQualified();
1119
1120  llvm::Value *SizeVal =
1121    llvm::ConstantInt::get(IntPtrTy,
1122                           getContext().getTypeSizeInChars(type).getQuantity());
1123
1124  llvm::Type *BP = Int8PtrTy;
1125  if (Loc->getType() != BP)
1126    Loc = Builder.CreateBitCast(Loc, BP);
1127
1128  // If the initializer is all or mostly zeros, codegen with memset then do
1129  // a few stores afterward.
1130  if (shouldUseMemSetPlusStoresToInitialize(constant,
1131                CGM.getDataLayout().getTypeAllocSize(constant->getType()))) {
1132    Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal,
1133                         alignment.getQuantity(), isVolatile);
1134    // Zero and undef don't require a stores.
1135    if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) {
1136      Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo());
1137      emitStoresForInitAfterMemset(constant, Loc, isVolatile, Builder);
1138    }
1139  } else {
1140    // Otherwise, create a temporary global with the initializer then
1141    // memcpy from the global to the alloca.
1142    std::string Name = GetStaticDeclName(*this, D, ".");
1143    llvm::GlobalVariable *GV =
1144      new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true,
1145                               llvm::GlobalValue::PrivateLinkage,
1146                               constant, Name);
1147    GV->setAlignment(alignment.getQuantity());
1148    GV->setUnnamedAddr(true);
1149
1150    llvm::Value *SrcPtr = GV;
1151    if (SrcPtr->getType() != BP)
1152      SrcPtr = Builder.CreateBitCast(SrcPtr, BP);
1153
1154    Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, alignment.getQuantity(),
1155                         isVolatile);
1156  }
1157}
1158
1159/// Emit an expression as an initializer for a variable at the given
1160/// location.  The expression is not necessarily the normal
1161/// initializer for the variable, and the address is not necessarily
1162/// its normal location.
1163///
1164/// \param init the initializing expression
1165/// \param var the variable to act as if we're initializing
1166/// \param loc the address to initialize; its type is a pointer
1167///   to the LLVM mapping of the variable's type
1168/// \param alignment the alignment of the address
1169/// \param capturedByInit true if the variable is a __block variable
1170///   whose address is potentially changed by the initializer
1171void CodeGenFunction::EmitExprAsInit(const Expr *init,
1172                                     const ValueDecl *D,
1173                                     LValue lvalue,
1174                                     bool capturedByInit) {
1175  QualType type = D->getType();
1176
1177  if (type->isReferenceType()) {
1178    RValue rvalue = EmitReferenceBindingToExpr(init);
1179    if (capturedByInit)
1180      drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1181    EmitStoreThroughLValue(rvalue, lvalue, true);
1182    return;
1183  }
1184  switch (getEvaluationKind(type)) {
1185  case TEK_Scalar:
1186    EmitScalarInit(init, D, lvalue, capturedByInit);
1187    return;
1188  case TEK_Complex: {
1189    ComplexPairTy complex = EmitComplexExpr(init);
1190    if (capturedByInit)
1191      drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1192    EmitStoreOfComplex(complex, lvalue, /*init*/ true);
1193    return;
1194  }
1195  case TEK_Aggregate:
1196    if (type->isAtomicType()) {
1197      EmitAtomicInit(const_cast<Expr*>(init), lvalue);
1198    } else {
1199      // TODO: how can we delay here if D is captured by its initializer?
1200      EmitAggExpr(init, AggValueSlot::forLValue(lvalue,
1201                                              AggValueSlot::IsDestructed,
1202                                         AggValueSlot::DoesNotNeedGCBarriers,
1203                                              AggValueSlot::IsNotAliased));
1204    }
1205    return;
1206  }
1207  llvm_unreachable("bad evaluation kind");
1208}
1209
1210/// Enter a destroy cleanup for the given local variable.
1211void CodeGenFunction::emitAutoVarTypeCleanup(
1212                            const CodeGenFunction::AutoVarEmission &emission,
1213                            QualType::DestructionKind dtorKind) {
1214  assert(dtorKind != QualType::DK_none);
1215
1216  // Note that for __block variables, we want to destroy the
1217  // original stack object, not the possibly forwarded object.
1218  llvm::Value *addr = emission.getObjectAddress(*this);
1219
1220  const VarDecl *var = emission.Variable;
1221  QualType type = var->getType();
1222
1223  CleanupKind cleanupKind = NormalAndEHCleanup;
1224  CodeGenFunction::Destroyer *destroyer = 0;
1225
1226  switch (dtorKind) {
1227  case QualType::DK_none:
1228    llvm_unreachable("no cleanup for trivially-destructible variable");
1229
1230  case QualType::DK_cxx_destructor:
1231    // If there's an NRVO flag on the emission, we need a different
1232    // cleanup.
1233    if (emission.NRVOFlag) {
1234      assert(!type->isArrayType());
1235      CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor();
1236      EHStack.pushCleanup<DestroyNRVOVariable>(cleanupKind, addr, dtor,
1237                                               emission.NRVOFlag);
1238      return;
1239    }
1240    break;
1241
1242  case QualType::DK_objc_strong_lifetime:
1243    // Suppress cleanups for pseudo-strong variables.
1244    if (var->isARCPseudoStrong()) return;
1245
1246    // Otherwise, consider whether to use an EH cleanup or not.
1247    cleanupKind = getARCCleanupKind();
1248
1249    // Use the imprecise destroyer by default.
1250    if (!var->hasAttr<ObjCPreciseLifetimeAttr>())
1251      destroyer = CodeGenFunction::destroyARCStrongImprecise;
1252    break;
1253
1254  case QualType::DK_objc_weak_lifetime:
1255    break;
1256  }
1257
1258  // If we haven't chosen a more specific destroyer, use the default.
1259  if (!destroyer) destroyer = getDestroyer(dtorKind);
1260
1261  // Use an EH cleanup in array destructors iff the destructor itself
1262  // is being pushed as an EH cleanup.
1263  bool useEHCleanup = (cleanupKind & EHCleanup);
1264  EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer,
1265                                     useEHCleanup);
1266}
1267
1268void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
1269  assert(emission.Variable && "emission was not valid!");
1270
1271  // If this was emitted as a global constant, we're done.
1272  if (emission.wasEmittedAsGlobal()) return;
1273
1274  // If we don't have an insertion point, we're done.  Sema prevents
1275  // us from jumping into any of these scopes anyway.
1276  if (!HaveInsertPoint()) return;
1277
1278  const VarDecl &D = *emission.Variable;
1279
1280  // Make sure we call @llvm.lifetime.end.  This needs to happen
1281  // *last*, so the cleanup needs to be pushed *first*.
1282  if (emission.useLifetimeMarkers()) {
1283    EHStack.pushCleanup<CallLifetimeEnd>(NormalCleanup,
1284                                         emission.getAllocatedAddress(),
1285                                         emission.getSizeForLifetimeMarkers());
1286  }
1287
1288  // Check the type for a cleanup.
1289  if (QualType::DestructionKind dtorKind = D.getType().isDestructedType())
1290    emitAutoVarTypeCleanup(emission, dtorKind);
1291
1292  // In GC mode, honor objc_precise_lifetime.
1293  if (getLangOpts().getGC() != LangOptions::NonGC &&
1294      D.hasAttr<ObjCPreciseLifetimeAttr>()) {
1295    EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D);
1296  }
1297
1298  // Handle the cleanup attribute.
1299  if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
1300    const FunctionDecl *FD = CA->getFunctionDecl();
1301
1302    llvm::Constant *F = CGM.GetAddrOfFunction(FD);
1303    assert(F && "Could not find function!");
1304
1305    const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD);
1306    EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D);
1307  }
1308
1309  // If this is a block variable, call _Block_object_destroy
1310  // (on the unforwarded address).
1311  if (emission.IsByRef)
1312    enterByrefCleanup(emission);
1313}
1314
1315CodeGenFunction::Destroyer *
1316CodeGenFunction::getDestroyer(QualType::DestructionKind kind) {
1317  switch (kind) {
1318  case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor");
1319  case QualType::DK_cxx_destructor:
1320    return destroyCXXObject;
1321  case QualType::DK_objc_strong_lifetime:
1322    return destroyARCStrongPrecise;
1323  case QualType::DK_objc_weak_lifetime:
1324    return destroyARCWeak;
1325  }
1326  llvm_unreachable("Unknown DestructionKind");
1327}
1328
1329/// pushEHDestroy - Push the standard destructor for the given type as
1330/// an EH-only cleanup.
1331void CodeGenFunction::pushEHDestroy(QualType::DestructionKind dtorKind,
1332                                  llvm::Value *addr, QualType type) {
1333  assert(dtorKind && "cannot push destructor for trivial type");
1334  assert(needsEHCleanup(dtorKind));
1335
1336  pushDestroy(EHCleanup, addr, type, getDestroyer(dtorKind), true);
1337}
1338
1339/// pushDestroy - Push the standard destructor for the given type as
1340/// at least a normal cleanup.
1341void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind,
1342                                  llvm::Value *addr, QualType type) {
1343  assert(dtorKind && "cannot push destructor for trivial type");
1344
1345  CleanupKind cleanupKind = getCleanupKind(dtorKind);
1346  pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind),
1347              cleanupKind & EHCleanup);
1348}
1349
1350void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, llvm::Value *addr,
1351                                  QualType type, Destroyer *destroyer,
1352                                  bool useEHCleanupForArray) {
1353  pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type,
1354                                     destroyer, useEHCleanupForArray);
1355}
1356
1357void CodeGenFunction::pushLifetimeExtendedDestroy(
1358    CleanupKind cleanupKind, llvm::Value *addr, QualType type,
1359    Destroyer *destroyer, bool useEHCleanupForArray) {
1360  assert(!isInConditionalBranch() &&
1361         "performing lifetime extension from within conditional");
1362
1363  // Push an EH-only cleanup for the object now.
1364  // FIXME: When popping normal cleanups, we need to keep this EH cleanup
1365  // around in case a temporary's destructor throws an exception.
1366  if (cleanupKind & EHCleanup)
1367    EHStack.pushCleanup<DestroyObject>(
1368        static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), addr, type,
1369        destroyer, useEHCleanupForArray);
1370
1371  // Remember that we need to push a full cleanup for the object at the
1372  // end of the full-expression.
1373  pushCleanupAfterFullExpr<DestroyObject>(
1374      cleanupKind, addr, type, destroyer, useEHCleanupForArray);
1375}
1376
1377/// emitDestroy - Immediately perform the destruction of the given
1378/// object.
1379///
1380/// \param addr - the address of the object; a type*
1381/// \param type - the type of the object; if an array type, all
1382///   objects are destroyed in reverse order
1383/// \param destroyer - the function to call to destroy individual
1384///   elements
1385/// \param useEHCleanupForArray - whether an EH cleanup should be
1386///   used when destroying array elements, in case one of the
1387///   destructions throws an exception
1388void CodeGenFunction::emitDestroy(llvm::Value *addr, QualType type,
1389                                  Destroyer *destroyer,
1390                                  bool useEHCleanupForArray) {
1391  const ArrayType *arrayType = getContext().getAsArrayType(type);
1392  if (!arrayType)
1393    return destroyer(*this, addr, type);
1394
1395  llvm::Value *begin = addr;
1396  llvm::Value *length = emitArrayLength(arrayType, type, begin);
1397
1398  // Normally we have to check whether the array is zero-length.
1399  bool checkZeroLength = true;
1400
1401  // But if the array length is constant, we can suppress that.
1402  if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) {
1403    // ...and if it's constant zero, we can just skip the entire thing.
1404    if (constLength->isZero()) return;
1405    checkZeroLength = false;
1406  }
1407
1408  llvm::Value *end = Builder.CreateInBoundsGEP(begin, length);
1409  emitArrayDestroy(begin, end, type, destroyer,
1410                   checkZeroLength, useEHCleanupForArray);
1411}
1412
1413/// emitArrayDestroy - Destroys all the elements of the given array,
1414/// beginning from last to first.  The array cannot be zero-length.
1415///
1416/// \param begin - a type* denoting the first element of the array
1417/// \param end - a type* denoting one past the end of the array
1418/// \param type - the element type of the array
1419/// \param destroyer - the function to call to destroy elements
1420/// \param useEHCleanup - whether to push an EH cleanup to destroy
1421///   the remaining elements in case the destruction of a single
1422///   element throws
1423void CodeGenFunction::emitArrayDestroy(llvm::Value *begin,
1424                                       llvm::Value *end,
1425                                       QualType type,
1426                                       Destroyer *destroyer,
1427                                       bool checkZeroLength,
1428                                       bool useEHCleanup) {
1429  assert(!type->isArrayType());
1430
1431  // The basic structure here is a do-while loop, because we don't
1432  // need to check for the zero-element case.
1433  llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body");
1434  llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done");
1435
1436  if (checkZeroLength) {
1437    llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end,
1438                                                "arraydestroy.isempty");
1439    Builder.CreateCondBr(isEmpty, doneBB, bodyBB);
1440  }
1441
1442  // Enter the loop body, making that address the current address.
1443  llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1444  EmitBlock(bodyBB);
1445  llvm::PHINode *elementPast =
1446    Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast");
1447  elementPast->addIncoming(end, entryBB);
1448
1449  // Shift the address back by one element.
1450  llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true);
1451  llvm::Value *element = Builder.CreateInBoundsGEP(elementPast, negativeOne,
1452                                                   "arraydestroy.element");
1453
1454  if (useEHCleanup)
1455    pushRegularPartialArrayCleanup(begin, element, type, destroyer);
1456
1457  // Perform the actual destruction there.
1458  destroyer(*this, element, type);
1459
1460  if (useEHCleanup)
1461    PopCleanupBlock();
1462
1463  // Check whether we've reached the end.
1464  llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done");
1465  Builder.CreateCondBr(done, doneBB, bodyBB);
1466  elementPast->addIncoming(element, Builder.GetInsertBlock());
1467
1468  // Done.
1469  EmitBlock(doneBB);
1470}
1471
1472/// Perform partial array destruction as if in an EH cleanup.  Unlike
1473/// emitArrayDestroy, the element type here may still be an array type.
1474static void emitPartialArrayDestroy(CodeGenFunction &CGF,
1475                                    llvm::Value *begin, llvm::Value *end,
1476                                    QualType type,
1477                                    CodeGenFunction::Destroyer *destroyer) {
1478  // If the element type is itself an array, drill down.
1479  unsigned arrayDepth = 0;
1480  while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) {
1481    // VLAs don't require a GEP index to walk into.
1482    if (!isa<VariableArrayType>(arrayType))
1483      arrayDepth++;
1484    type = arrayType->getElementType();
1485  }
1486
1487  if (arrayDepth) {
1488    llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, arrayDepth+1);
1489
1490    SmallVector<llvm::Value*,4> gepIndices(arrayDepth, zero);
1491    begin = CGF.Builder.CreateInBoundsGEP(begin, gepIndices, "pad.arraybegin");
1492    end = CGF.Builder.CreateInBoundsGEP(end, gepIndices, "pad.arrayend");
1493  }
1494
1495  // Destroy the array.  We don't ever need an EH cleanup because we
1496  // assume that we're in an EH cleanup ourselves, so a throwing
1497  // destructor causes an immediate terminate.
1498  CGF.emitArrayDestroy(begin, end, type, destroyer,
1499                       /*checkZeroLength*/ true, /*useEHCleanup*/ false);
1500}
1501
1502namespace {
1503  /// RegularPartialArrayDestroy - a cleanup which performs a partial
1504  /// array destroy where the end pointer is regularly determined and
1505  /// does not need to be loaded from a local.
1506  class RegularPartialArrayDestroy : public EHScopeStack::Cleanup {
1507    llvm::Value *ArrayBegin;
1508    llvm::Value *ArrayEnd;
1509    QualType ElementType;
1510    CodeGenFunction::Destroyer *Destroyer;
1511  public:
1512    RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd,
1513                               QualType elementType,
1514                               CodeGenFunction::Destroyer *destroyer)
1515      : ArrayBegin(arrayBegin), ArrayEnd(arrayEnd),
1516        ElementType(elementType), Destroyer(destroyer) {}
1517
1518    void Emit(CodeGenFunction &CGF, Flags flags) {
1519      emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd,
1520                              ElementType, Destroyer);
1521    }
1522  };
1523
1524  /// IrregularPartialArrayDestroy - a cleanup which performs a
1525  /// partial array destroy where the end pointer is irregularly
1526  /// determined and must be loaded from a local.
1527  class IrregularPartialArrayDestroy : public EHScopeStack::Cleanup {
1528    llvm::Value *ArrayBegin;
1529    llvm::Value *ArrayEndPointer;
1530    QualType ElementType;
1531    CodeGenFunction::Destroyer *Destroyer;
1532  public:
1533    IrregularPartialArrayDestroy(llvm::Value *arrayBegin,
1534                                 llvm::Value *arrayEndPointer,
1535                                 QualType elementType,
1536                                 CodeGenFunction::Destroyer *destroyer)
1537      : ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer),
1538        ElementType(elementType), Destroyer(destroyer) {}
1539
1540    void Emit(CodeGenFunction &CGF, Flags flags) {
1541      llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer);
1542      emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd,
1543                              ElementType, Destroyer);
1544    }
1545  };
1546}
1547
1548/// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy
1549/// already-constructed elements of the given array.  The cleanup
1550/// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1551///
1552/// \param elementType - the immediate element type of the array;
1553///   possibly still an array type
1554void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
1555                                                 llvm::Value *arrayEndPointer,
1556                                                       QualType elementType,
1557                                                       Destroyer *destroyer) {
1558  pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup,
1559                                                    arrayBegin, arrayEndPointer,
1560                                                    elementType, destroyer);
1561}
1562
1563/// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
1564/// already-constructed elements of the given array.  The cleanup
1565/// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1566///
1567/// \param elementType - the immediate element type of the array;
1568///   possibly still an array type
1569void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin,
1570                                                     llvm::Value *arrayEnd,
1571                                                     QualType elementType,
1572                                                     Destroyer *destroyer) {
1573  pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup,
1574                                                  arrayBegin, arrayEnd,
1575                                                  elementType, destroyer);
1576}
1577
1578/// Lazily declare the @llvm.lifetime.start intrinsic.
1579llvm::Constant *CodeGenModule::getLLVMLifetimeStartFn() {
1580  if (LifetimeStartFn) return LifetimeStartFn;
1581  LifetimeStartFn = llvm::Intrinsic::getDeclaration(&getModule(),
1582                                            llvm::Intrinsic::lifetime_start);
1583  return LifetimeStartFn;
1584}
1585
1586/// Lazily declare the @llvm.lifetime.end intrinsic.
1587llvm::Constant *CodeGenModule::getLLVMLifetimeEndFn() {
1588  if (LifetimeEndFn) return LifetimeEndFn;
1589  LifetimeEndFn = llvm::Intrinsic::getDeclaration(&getModule(),
1590                                              llvm::Intrinsic::lifetime_end);
1591  return LifetimeEndFn;
1592}
1593
1594namespace {
1595  /// A cleanup to perform a release of an object at the end of a
1596  /// function.  This is used to balance out the incoming +1 of a
1597  /// ns_consumed argument when we can't reasonably do that just by
1598  /// not doing the initial retain for a __block argument.
1599  struct ConsumeARCParameter : EHScopeStack::Cleanup {
1600    ConsumeARCParameter(llvm::Value *param,
1601                        ARCPreciseLifetime_t precise)
1602      : Param(param), Precise(precise) {}
1603
1604    llvm::Value *Param;
1605    ARCPreciseLifetime_t Precise;
1606
1607    void Emit(CodeGenFunction &CGF, Flags flags) {
1608      CGF.EmitARCRelease(Param, Precise);
1609    }
1610  };
1611}
1612
1613/// Emit an alloca (or GlobalValue depending on target)
1614/// for the specified parameter and set up LocalDeclMap.
1615void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
1616                                   unsigned ArgNo) {
1617  // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
1618  assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
1619         "Invalid argument to EmitParmDecl");
1620
1621  Arg->setName(D.getName());
1622
1623  QualType Ty = D.getType();
1624
1625  // Use better IR generation for certain implicit parameters.
1626  if (isa<ImplicitParamDecl>(D)) {
1627    // The only implicit argument a block has is its literal.
1628    if (BlockInfo) {
1629      LocalDeclMap[&D] = Arg;
1630      llvm::Value *LocalAddr = 0;
1631      if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1632        // Allocate a stack slot to let the debug info survive the RA.
1633        llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1634                                                   D.getName() + ".addr");
1635        Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity());
1636        LValue lv = MakeAddrLValue(Alloc, Ty, getContext().getDeclAlign(&D));
1637        EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1638        LocalAddr = Builder.CreateLoad(Alloc);
1639      }
1640
1641      if (CGDebugInfo *DI = getDebugInfo()) {
1642        if (CGM.getCodeGenOpts().getDebugInfo()
1643              >= CodeGenOptions::LimitedDebugInfo) {
1644          DI->setLocation(D.getLocation());
1645          DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, Arg, LocalAddr, Builder);
1646        }
1647      }
1648
1649      return;
1650    }
1651  }
1652
1653  llvm::Value *DeclPtr;
1654  // If this is an aggregate or variable sized value, reuse the input pointer.
1655  if (!Ty->isConstantSizeType() ||
1656      !CodeGenFunction::hasScalarEvaluationKind(Ty)) {
1657    DeclPtr = Arg;
1658  } else {
1659    // Otherwise, create a temporary to hold the value.
1660    llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1661                                               D.getName() + ".addr");
1662    CharUnits Align = getContext().getDeclAlign(&D);
1663    Alloc->setAlignment(Align.getQuantity());
1664    DeclPtr = Alloc;
1665
1666    bool doStore = true;
1667
1668    Qualifiers qs = Ty.getQualifiers();
1669    LValue lv = MakeAddrLValue(DeclPtr, Ty, Align);
1670    if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) {
1671      // We honor __attribute__((ns_consumed)) for types with lifetime.
1672      // For __strong, it's handled by just skipping the initial retain;
1673      // otherwise we have to balance out the initial +1 with an extra
1674      // cleanup to do the release at the end of the function.
1675      bool isConsumed = D.hasAttr<NSConsumedAttr>();
1676
1677      // 'self' is always formally __strong, but if this is not an
1678      // init method then we don't want to retain it.
1679      if (D.isARCPseudoStrong()) {
1680        const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CurCodeDecl);
1681        assert(&D == method->getSelfDecl());
1682        assert(lt == Qualifiers::OCL_Strong);
1683        assert(qs.hasConst());
1684        assert(method->getMethodFamily() != OMF_init);
1685        (void) method;
1686        lt = Qualifiers::OCL_ExplicitNone;
1687      }
1688
1689      if (lt == Qualifiers::OCL_Strong) {
1690        if (!isConsumed) {
1691          if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1692            // use objc_storeStrong(&dest, value) for retaining the
1693            // object. But first, store a null into 'dest' because
1694            // objc_storeStrong attempts to release its old value.
1695            llvm::Value * Null = CGM.EmitNullConstant(D.getType());
1696            EmitStoreOfScalar(Null, lv, /* isInitialization */ true);
1697            EmitARCStoreStrongCall(lv.getAddress(), Arg, true);
1698            doStore = false;
1699          }
1700          else
1701          // Don't use objc_retainBlock for block pointers, because we
1702          // don't want to Block_copy something just because we got it
1703          // as a parameter.
1704            Arg = EmitARCRetainNonBlock(Arg);
1705        }
1706      } else {
1707        // Push the cleanup for a consumed parameter.
1708        if (isConsumed) {
1709          ARCPreciseLifetime_t precise = (D.hasAttr<ObjCPreciseLifetimeAttr>()
1710                                ? ARCPreciseLifetime : ARCImpreciseLifetime);
1711          EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), Arg,
1712                                                   precise);
1713        }
1714
1715        if (lt == Qualifiers::OCL_Weak) {
1716          EmitARCInitWeak(DeclPtr, Arg);
1717          doStore = false; // The weak init is a store, no need to do two.
1718        }
1719      }
1720
1721      // Enter the cleanup scope.
1722      EmitAutoVarWithLifetime(*this, D, DeclPtr, lt);
1723    }
1724
1725    // Store the initial value into the alloca.
1726    if (doStore)
1727      EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1728  }
1729
1730  llvm::Value *&DMEntry = LocalDeclMap[&D];
1731  assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
1732  DMEntry = DeclPtr;
1733
1734  // Emit debug info for param declaration.
1735  if (CGDebugInfo *DI = getDebugInfo()) {
1736    if (CGM.getCodeGenOpts().getDebugInfo()
1737          >= CodeGenOptions::LimitedDebugInfo) {
1738      DI->EmitDeclareOfArgVariable(&D, DeclPtr, ArgNo, Builder);
1739    }
1740  }
1741
1742  if (D.hasAttr<AnnotateAttr>())
1743      EmitVarAnnotations(&D, DeclPtr);
1744}
1745