1 //===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This contains code to emit Decl nodes as LLVM code.
12 //===----------------------------------------------------------------------===//
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"
29 using namespace clang;
30 using namespace CodeGen;
33 void CodeGenFunction::EmitDecl(const Decl &D) {
34 switch (D.getKind()) {
35 case Decl::TranslationUnit:
37 case Decl::UnresolvedUsingTypename:
38 case Decl::ClassTemplateSpecialization:
39 case Decl::ClassTemplatePartialSpecialization:
40 case Decl::TemplateTypeParm:
41 case Decl::UnresolvedUsingValue:
42 case Decl::NonTypeTemplateParm:
44 case Decl::CXXConstructor:
45 case Decl::CXXDestructor:
46 case Decl::CXXConversion:
48 case Decl::MSProperty:
49 case Decl::IndirectField:
51 case Decl::ObjCAtDefsField:
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:
71 case Decl::FriendTemplate:
74 case Decl::ClassScopeFunctionSpecialization:
75 llvm_unreachable("Declaration should not be in declstmts!");
76 case Decl::Function: // void X();
77 case Decl::Record: // struct/union/class X;
78 case Decl::Enum: // enum X;
79 case Decl::EnumConstant: // enum ? { X = ? }
80 case Decl::CXXRecord: // struct/union/class X; [C++]
81 case Decl::Using: // using X; [C++]
82 case Decl::UsingShadow:
83 case Decl::NamespaceAlias:
84 case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
85 case Decl::Label: // __label__ x;
87 case Decl::OMPThreadPrivate:
89 // None of these decls require codegen support.
92 case Decl::UsingDirective: // using namespace X; [C++]
93 if (CGDebugInfo *DI = getDebugInfo())
94 DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D));
97 const VarDecl &VD = cast<VarDecl>(D);
98 assert(VD.isLocalVarDecl() &&
99 "Should not see file-scope variables inside a function!");
100 return EmitVarDecl(VD);
103 case Decl::Typedef: // typedef int X;
104 case Decl::TypeAlias: { // using X = int; [C++0x]
105 const TypedefNameDecl &TD = cast<TypedefNameDecl>(D);
106 QualType Ty = TD.getUnderlyingType();
108 if (Ty->isVariablyModifiedType())
109 EmitVariablyModifiedType(Ty);
114 /// EmitVarDecl - This method handles emission of any variable declaration
115 /// inside a function, including static vars etc.
116 void CodeGenFunction::EmitVarDecl(const VarDecl &D) {
117 switch (D.getStorageClass()) {
121 return EmitAutoVarDecl(D);
123 llvm::GlobalValue::LinkageTypes Linkage =
124 llvm::GlobalValue::InternalLinkage;
126 // If the function definition has some sort of weak linkage, its
127 // static variables should also be weak so that they get properly
128 // uniqued. We can't do this in C, though, because there's no
129 // standard way to agree on which variables are the same (i.e.
130 // there's no mangling).
131 if (getLangOpts().CPlusPlus)
132 if (llvm::GlobalValue::isWeakForLinker(CurFn->getLinkage()))
133 Linkage = CurFn->getLinkage();
135 return EmitStaticVarDecl(D, Linkage);
138 case SC_PrivateExtern:
139 // Don't emit it now, allow it to be emitted lazily on its first use.
141 case SC_OpenCLWorkGroupLocal:
142 return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D);
145 llvm_unreachable("Unknown storage class");
148 static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D,
149 const char *Separator) {
150 CodeGenModule &CGM = CGF.CGM;
151 if (CGF.getLangOpts().CPlusPlus) {
152 StringRef Name = CGM.getMangledName(&D);
156 std::string ContextName;
157 if (!CGF.CurFuncDecl) {
158 // Better be in a block declared in global scope.
159 const NamedDecl *ND = cast<NamedDecl>(&D);
160 const DeclContext *DC = ND->getDeclContext();
161 if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) {
163 CGM.getBlockMangledName(GlobalDecl(), Name, BD);
164 ContextName = Name.getString();
167 llvm_unreachable("Unknown context for block static var decl");
168 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl)) {
169 StringRef Name = CGM.getMangledName(FD);
170 ContextName = Name.str();
171 } else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl))
172 ContextName = CGF.CurFn->getName();
174 llvm_unreachable("Unknown context for static var decl");
176 return ContextName + Separator + D.getNameAsString();
179 llvm::GlobalVariable *
180 CodeGenFunction::CreateStaticVarDecl(const VarDecl &D,
181 const char *Separator,
182 llvm::GlobalValue::LinkageTypes Linkage) {
183 QualType Ty = D.getType();
184 assert(Ty->isConstantSizeType() && "VLAs can't be static");
186 // Use the label if the variable is renamed with the asm-label extension.
188 if (D.hasAttr<AsmLabelAttr>())
189 Name = CGM.getMangledName(&D);
191 Name = GetStaticDeclName(*this, D, Separator);
193 llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty);
195 CGM.GetGlobalVarAddressSpace(&D, CGM.getContext().getTargetAddressSpace(Ty));
196 llvm::GlobalVariable *GV =
197 new llvm::GlobalVariable(CGM.getModule(), LTy,
198 Ty.isConstant(getContext()), Linkage,
199 CGM.EmitNullConstant(D.getType()), Name, 0,
200 llvm::GlobalVariable::NotThreadLocal,
202 GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
203 if (Linkage != llvm::GlobalValue::InternalLinkage)
204 GV->setVisibility(CurFn->getVisibility());
207 CGM.setTLSMode(GV, D);
212 /// hasNontrivialDestruction - Determine whether a type's destruction is
213 /// non-trivial. If so, and the variable uses static initialization, we must
214 /// register its destructor to run on exit.
215 static bool hasNontrivialDestruction(QualType T) {
216 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
217 return RD && !RD->hasTrivialDestructor();
220 /// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the
221 /// global variable that has already been created for it. If the initializer
222 /// has a different type than GV does, this may free GV and return a different
223 /// one. Otherwise it just returns GV.
224 llvm::GlobalVariable *
225 CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
226 llvm::GlobalVariable *GV) {
227 llvm::Constant *Init = CGM.EmitConstantInit(D, this);
229 // If constant emission failed, then this should be a C++ static
232 if (!getLangOpts().CPlusPlus)
233 CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
234 else if (Builder.GetInsertBlock()) {
235 // Since we have a static initializer, this global variable can't
237 GV->setConstant(false);
239 EmitCXXGuardedInit(D, GV, /*PerformInit*/true);
244 // The initializer may differ in type from the global. Rewrite
245 // the global to match the initializer. (We have to do this
246 // because some types, like unions, can't be completely represented
247 // in the LLVM type system.)
248 if (GV->getType()->getElementType() != Init->getType()) {
249 llvm::GlobalVariable *OldGV = GV;
251 GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
253 OldGV->getLinkage(), Init, "",
254 /*InsertBefore*/ OldGV,
255 OldGV->getThreadLocalMode(),
256 CGM.getContext().getTargetAddressSpace(D.getType()));
257 GV->setVisibility(OldGV->getVisibility());
259 // Steal the name of the old global
262 // Replace all uses of the old global with the new global
263 llvm::Constant *NewPtrForOldDecl =
264 llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
265 OldGV->replaceAllUsesWith(NewPtrForOldDecl);
267 // Erase the old global, since it is no longer used.
268 OldGV->eraseFromParent();
271 GV->setConstant(CGM.isTypeConstant(D.getType(), true));
272 GV->setInitializer(Init);
274 if (hasNontrivialDestruction(D.getType())) {
275 // We have a constant initializer, but a nontrivial destructor. We still
276 // need to perform a guarded "initialization" in order to register the
278 EmitCXXGuardedInit(D, GV, /*PerformInit*/false);
284 void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
285 llvm::GlobalValue::LinkageTypes Linkage) {
286 llvm::Value *&DMEntry = LocalDeclMap[&D];
287 assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
289 // Check to see if we already have a global variable for this
290 // declaration. This can happen when double-emitting function
291 // bodies, e.g. with complete and base constructors.
292 llvm::Constant *addr =
293 CGM.getStaticLocalDeclAddress(&D);
295 llvm::GlobalVariable *var;
297 var = cast<llvm::GlobalVariable>(addr->stripPointerCasts());
299 addr = var = CreateStaticVarDecl(D, ".", Linkage);
302 // Store into LocalDeclMap before generating initializer to handle
303 // circular references.
305 CGM.setStaticLocalDeclAddress(&D, addr);
307 // We can't have a VLA here, but we can have a pointer to a VLA,
308 // even though that doesn't really make any sense.
309 // Make sure to evaluate VLA bounds now so that we have them for later.
310 if (D.getType()->isVariablyModifiedType())
311 EmitVariablyModifiedType(D.getType());
313 // Save the type in case adding the initializer forces a type change.
314 llvm::Type *expectedType = addr->getType();
316 // If this value has an initializer, emit it.
318 var = AddInitializerToStaticVarDecl(D, var);
320 var->setAlignment(getContext().getDeclAlign(&D).getQuantity());
322 if (D.hasAttr<AnnotateAttr>())
323 CGM.AddGlobalAnnotations(&D, var);
325 if (const SectionAttr *SA = D.getAttr<SectionAttr>())
326 var->setSection(SA->getName());
328 if (D.hasAttr<UsedAttr>())
329 CGM.AddUsedGlobal(var);
331 // We may have to cast the constant because of the initializer
334 // FIXME: It is really dangerous to store this in the map; if anyone
335 // RAUW's the GV uses of this constant will be invalid.
336 llvm::Constant *castedAddr = llvm::ConstantExpr::getBitCast(var, expectedType);
337 DMEntry = castedAddr;
338 CGM.setStaticLocalDeclAddress(&D, castedAddr);
340 // Emit global variable debug descriptor for static vars.
341 CGDebugInfo *DI = getDebugInfo();
343 CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) {
344 DI->setLocation(D.getLocation());
345 DI->EmitGlobalVariable(var, &D);
350 struct DestroyObject : EHScopeStack::Cleanup {
351 DestroyObject(llvm::Value *addr, QualType type,
352 CodeGenFunction::Destroyer *destroyer,
353 bool useEHCleanupForArray)
354 : addr(addr), type(type), destroyer(destroyer),
355 useEHCleanupForArray(useEHCleanupForArray) {}
359 CodeGenFunction::Destroyer *destroyer;
360 bool useEHCleanupForArray;
362 void Emit(CodeGenFunction &CGF, Flags flags) {
363 // Don't use an EH cleanup recursively from an EH cleanup.
364 bool useEHCleanupForArray =
365 flags.isForNormalCleanup() && this->useEHCleanupForArray;
367 CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray);
371 struct DestroyNRVOVariable : EHScopeStack::Cleanup {
372 DestroyNRVOVariable(llvm::Value *addr,
373 const CXXDestructorDecl *Dtor,
374 llvm::Value *NRVOFlag)
375 : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(addr) {}
377 const CXXDestructorDecl *Dtor;
378 llvm::Value *NRVOFlag;
381 void Emit(CodeGenFunction &CGF, Flags flags) {
382 // Along the exceptions path we always execute the dtor.
383 bool NRVO = flags.isForNormalCleanup() && NRVOFlag;
385 llvm::BasicBlock *SkipDtorBB = 0;
387 // If we exited via NRVO, we skip the destructor call.
388 llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused");
389 SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor");
390 llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val");
391 CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB);
392 CGF.EmitBlock(RunDtorBB);
395 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
396 /*ForVirtualBase=*/false,
397 /*Delegating=*/false,
400 if (NRVO) CGF.EmitBlock(SkipDtorBB);
404 struct CallStackRestore : EHScopeStack::Cleanup {
406 CallStackRestore(llvm::Value *Stack) : Stack(Stack) {}
407 void Emit(CodeGenFunction &CGF, Flags flags) {
408 llvm::Value *V = CGF.Builder.CreateLoad(Stack);
409 llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
410 CGF.Builder.CreateCall(F, V);
414 struct ExtendGCLifetime : EHScopeStack::Cleanup {
416 ExtendGCLifetime(const VarDecl *var) : Var(*var) {}
418 void Emit(CodeGenFunction &CGF, Flags flags) {
419 // Compute the address of the local variable, in case it's a
420 // byref or something.
421 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
422 Var.getType(), VK_LValue, SourceLocation());
423 llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE));
424 CGF.EmitExtendGCLifetime(value);
428 struct CallCleanupFunction : EHScopeStack::Cleanup {
429 llvm::Constant *CleanupFn;
430 const CGFunctionInfo &FnInfo;
433 CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
435 : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {}
437 void Emit(CodeGenFunction &CGF, Flags flags) {
438 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
439 Var.getType(), VK_LValue, SourceLocation());
440 // Compute the address of the local variable, in case it's a byref
442 llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getAddress();
444 // In some cases, the type of the function argument will be different from
445 // the type of the pointer. An example of this is
446 // void f(void* arg);
447 // __attribute__((cleanup(f))) void *g;
449 // To fix this we insert a bitcast here.
450 QualType ArgTy = FnInfo.arg_begin()->type;
452 CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy));
455 Args.add(RValue::get(Arg),
456 CGF.getContext().getPointerType(Var.getType()));
457 CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args);
461 /// A cleanup to call @llvm.lifetime.end.
462 class CallLifetimeEnd : public EHScopeStack::Cleanup {
466 CallLifetimeEnd(llvm::Value *addr, llvm::Value *size)
467 : Addr(addr), Size(size) {}
469 void Emit(CodeGenFunction &CGF, Flags flags) {
470 llvm::Value *castAddr = CGF.Builder.CreateBitCast(Addr, CGF.Int8PtrTy);
471 CGF.Builder.CreateCall2(CGF.CGM.getLLVMLifetimeEndFn(),
478 /// EmitAutoVarWithLifetime - Does the setup required for an automatic
479 /// variable with lifetime.
480 static void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var,
482 Qualifiers::ObjCLifetime lifetime) {
484 case Qualifiers::OCL_None:
485 llvm_unreachable("present but none");
487 case Qualifiers::OCL_ExplicitNone:
491 case Qualifiers::OCL_Strong: {
492 CodeGenFunction::Destroyer *destroyer =
493 (var.hasAttr<ObjCPreciseLifetimeAttr>()
494 ? CodeGenFunction::destroyARCStrongPrecise
495 : CodeGenFunction::destroyARCStrongImprecise);
497 CleanupKind cleanupKind = CGF.getARCCleanupKind();
498 CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer,
499 cleanupKind & EHCleanup);
502 case Qualifiers::OCL_Autoreleasing:
506 case Qualifiers::OCL_Weak:
507 // __weak objects always get EH cleanups; otherwise, exceptions
508 // could cause really nasty crashes instead of mere leaks.
509 CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(),
510 CodeGenFunction::destroyARCWeak,
511 /*useEHCleanup*/ true);
516 static bool isAccessedBy(const VarDecl &var, const Stmt *s) {
517 if (const Expr *e = dyn_cast<Expr>(s)) {
518 // Skip the most common kinds of expressions that make
519 // hierarchy-walking expensive.
520 s = e = e->IgnoreParenCasts();
522 if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e))
523 return (ref->getDecl() == &var);
524 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
525 const BlockDecl *block = be->getBlockDecl();
526 for (BlockDecl::capture_const_iterator i = block->capture_begin(),
527 e = block->capture_end(); i != e; ++i) {
528 if (i->getVariable() == &var)
534 for (Stmt::const_child_range children = s->children(); children; ++children)
535 // children might be null; as in missing decl or conditional of an if-stmt.
536 if ((*children) && isAccessedBy(var, *children))
542 static bool isAccessedBy(const ValueDecl *decl, const Expr *e) {
543 if (!decl) return false;
544 if (!isa<VarDecl>(decl)) return false;
545 const VarDecl *var = cast<VarDecl>(decl);
546 return isAccessedBy(*var, e);
549 static void drillIntoBlockVariable(CodeGenFunction &CGF,
551 const VarDecl *var) {
552 lvalue.setAddress(CGF.BuildBlockByrefAddress(lvalue.getAddress(), var));
555 void CodeGenFunction::EmitScalarInit(const Expr *init,
558 bool capturedByInit) {
559 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
561 llvm::Value *value = EmitScalarExpr(init);
563 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
564 EmitStoreThroughLValue(RValue::get(value), lvalue, true);
568 // If we're emitting a value with lifetime, we have to do the
569 // initialization *before* we leave the cleanup scopes.
570 if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) {
571 enterFullExpression(ewc);
572 init = ewc->getSubExpr();
574 CodeGenFunction::RunCleanupsScope Scope(*this);
576 // We have to maintain the illusion that the variable is
577 // zero-initialized. If the variable might be accessed in its
578 // initializer, zero-initialize before running the initializer, then
579 // actually perform the initialization with an assign.
580 bool accessedByInit = false;
581 if (lifetime != Qualifiers::OCL_ExplicitNone)
582 accessedByInit = (capturedByInit || isAccessedBy(D, init));
583 if (accessedByInit) {
584 LValue tempLV = lvalue;
585 // Drill down to the __block object if necessary.
586 if (capturedByInit) {
587 // We can use a simple GEP for this because it can't have been
589 tempLV.setAddress(Builder.CreateStructGEP(tempLV.getAddress(),
590 getByRefValueLLVMField(cast<VarDecl>(D))));
593 llvm::PointerType *ty
594 = cast<llvm::PointerType>(tempLV.getAddress()->getType());
595 ty = cast<llvm::PointerType>(ty->getElementType());
597 llvm::Value *zero = llvm::ConstantPointerNull::get(ty);
599 // If __weak, we want to use a barrier under certain conditions.
600 if (lifetime == Qualifiers::OCL_Weak)
601 EmitARCInitWeak(tempLV.getAddress(), zero);
603 // Otherwise just do a simple store.
605 EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true);
608 // Emit the initializer.
609 llvm::Value *value = 0;
612 case Qualifiers::OCL_None:
613 llvm_unreachable("present but none");
615 case Qualifiers::OCL_ExplicitNone:
617 value = EmitScalarExpr(init);
620 case Qualifiers::OCL_Strong: {
621 value = EmitARCRetainScalarExpr(init);
625 case Qualifiers::OCL_Weak: {
626 // No way to optimize a producing initializer into this. It's not
627 // worth optimizing for, because the value will immediately
628 // disappear in the common case.
629 value = EmitScalarExpr(init);
631 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
633 EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true);
635 EmitARCInitWeak(lvalue.getAddress(), value);
639 case Qualifiers::OCL_Autoreleasing:
640 value = EmitARCRetainAutoreleaseScalarExpr(init);
644 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
646 // If the variable might have been accessed by its initializer, we
647 // might have to initialize with a barrier. We have to do this for
648 // both __weak and __strong, but __weak got filtered out above.
649 if (accessedByInit && lifetime == Qualifiers::OCL_Strong) {
650 llvm::Value *oldValue = EmitLoadOfScalar(lvalue);
651 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
652 EmitARCRelease(oldValue, ARCImpreciseLifetime);
656 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
659 /// EmitScalarInit - Initialize the given lvalue with the given object.
660 void CodeGenFunction::EmitScalarInit(llvm::Value *init, LValue lvalue) {
661 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
663 return EmitStoreThroughLValue(RValue::get(init), lvalue, true);
666 case Qualifiers::OCL_None:
667 llvm_unreachable("present but none");
669 case Qualifiers::OCL_ExplicitNone:
673 case Qualifiers::OCL_Strong:
674 init = EmitARCRetain(lvalue.getType(), init);
677 case Qualifiers::OCL_Weak:
678 // Initialize and then skip the primitive store.
679 EmitARCInitWeak(lvalue.getAddress(), init);
682 case Qualifiers::OCL_Autoreleasing:
683 init = EmitARCRetainAutorelease(lvalue.getType(), init);
687 EmitStoreOfScalar(init, lvalue, /* isInitialization */ true);
690 /// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the
691 /// non-zero parts of the specified initializer with equal or fewer than
692 /// NumStores scalar stores.
693 static bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init,
694 unsigned &NumStores) {
695 // Zero and Undef never requires any extra stores.
696 if (isa<llvm::ConstantAggregateZero>(Init) ||
697 isa<llvm::ConstantPointerNull>(Init) ||
698 isa<llvm::UndefValue>(Init))
700 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
701 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
702 isa<llvm::ConstantExpr>(Init))
703 return Init->isNullValue() || NumStores--;
705 // See if we can emit each element.
706 if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) {
707 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
708 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
709 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
715 if (llvm::ConstantDataSequential *CDS =
716 dyn_cast<llvm::ConstantDataSequential>(Init)) {
717 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
718 llvm::Constant *Elt = CDS->getElementAsConstant(i);
719 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
725 // Anything else is hard and scary.
729 /// emitStoresForInitAfterMemset - For inits that
730 /// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar
731 /// stores that would be required.
732 static void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc,
733 bool isVolatile, CGBuilderTy &Builder) {
734 assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) &&
735 "called emitStoresForInitAfterMemset for zero or undef value.");
737 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
738 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
739 isa<llvm::ConstantExpr>(Init)) {
740 Builder.CreateStore(Init, Loc, isVolatile);
744 if (llvm::ConstantDataSequential *CDS =
745 dyn_cast<llvm::ConstantDataSequential>(Init)) {
746 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
747 llvm::Constant *Elt = CDS->getElementAsConstant(i);
749 // If necessary, get a pointer to the element and emit it.
750 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
751 emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
752 isVolatile, Builder);
757 assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) &&
758 "Unknown value type!");
760 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
761 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
763 // If necessary, get a pointer to the element and emit it.
764 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
765 emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
766 isVolatile, Builder);
771 /// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset
772 /// plus some stores to initialize a local variable instead of using a memcpy
773 /// from a constant global. It is beneficial to use memset if the global is all
774 /// zeros, or mostly zeros and large.
775 static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init,
776 uint64_t GlobalSize) {
777 // If a global is all zeros, always use a memset.
778 if (isa<llvm::ConstantAggregateZero>(Init)) return true;
780 // If a non-zero global is <= 32 bytes, always use a memcpy. If it is large,
781 // do it if it will require 6 or fewer scalar stores.
782 // TODO: Should budget depends on the size? Avoiding a large global warrants
783 // plopping in more stores.
784 unsigned StoreBudget = 6;
785 uint64_t SizeLimit = 32;
787 return GlobalSize > SizeLimit &&
788 canEmitInitWithFewStoresAfterMemset(Init, StoreBudget);
791 /// Should we use the LLVM lifetime intrinsics for the given local variable?
792 static bool shouldUseLifetimeMarkers(CodeGenFunction &CGF, const VarDecl &D,
794 // Always emit lifetime markers in -fsanitize=use-after-scope mode.
795 if (CGF.getLangOpts().Sanitize.UseAfterScope)
797 // For now, only in optimized builds.
798 if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0)
801 // Limit the size of marked objects to 32 bytes. We don't want to increase
802 // compile time by marking tiny objects.
803 unsigned SizeThreshold = 32;
805 return Size > SizeThreshold;
809 /// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a
810 /// variable declaration with auto, register, or no storage class specifier.
811 /// These turn into simple stack objects, or GlobalValues depending on target.
812 void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
813 AutoVarEmission emission = EmitAutoVarAlloca(D);
814 EmitAutoVarInit(emission);
815 EmitAutoVarCleanups(emission);
818 /// EmitAutoVarAlloca - Emit the alloca and debug information for a
819 /// local variable. Does not emit initalization or destruction.
820 CodeGenFunction::AutoVarEmission
821 CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
822 QualType Ty = D.getType();
824 AutoVarEmission emission(D);
826 bool isByRef = D.hasAttr<BlocksAttr>();
827 emission.IsByRef = isByRef;
829 CharUnits alignment = getContext().getDeclAlign(&D);
830 emission.Alignment = alignment;
832 // If the type is variably-modified, emit all the VLA sizes for it.
833 if (Ty->isVariablyModifiedType())
834 EmitVariablyModifiedType(Ty);
836 llvm::Value *DeclPtr;
837 if (Ty->isConstantSizeType()) {
838 bool NRVO = getLangOpts().ElideConstructors &&
841 // If this value is a POD array or struct with a statically
842 // determinable constant initializer, there are optimizations we can do.
844 // TODO: We should constant-evaluate the initializer of any variable,
845 // as long as it is initialized by a constant expression. Currently,
846 // isConstantInitializer produces wrong answers for structs with
847 // reference or bitfield members, and a few other cases, and checking
848 // for POD-ness protects us from some of these.
850 (Ty->isArrayType() || Ty->isRecordType()) &&
851 (Ty.isPODType(getContext()) ||
852 getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) &&
853 D.getInit()->isConstantInitializer(getContext(), false)) {
855 // If the variable's a const type, and it's neither an NRVO
856 // candidate nor a __block variable and has no mutable members,
857 // emit it as a global instead.
858 if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef &&
859 CGM.isTypeConstant(Ty, true)) {
860 EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
862 emission.Address = 0; // signal this condition to later callbacks
863 assert(emission.wasEmittedAsGlobal());
867 // Otherwise, tell the initialization code that we're in this case.
868 emission.IsConstantAggregate = true;
871 // A normal fixed sized variable becomes an alloca in the entry block,
872 // unless it's an NRVO variable.
873 llvm::Type *LTy = ConvertTypeForMem(Ty);
876 // The named return value optimization: allocate this variable in the
877 // return slot, so that we can elide the copy when returning this
878 // variable (C++0x [class.copy]p34).
879 DeclPtr = ReturnValue;
881 if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
882 if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) {
883 // Create a flag that is used to indicate when the NRVO was applied
884 // to this variable. Set it to zero to indicate that NRVO was not
886 llvm::Value *Zero = Builder.getFalse();
887 llvm::Value *NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo");
889 Builder.CreateStore(Zero, NRVOFlag);
891 // Record the NRVO flag for this variable.
892 NRVOFlags[&D] = NRVOFlag;
893 emission.NRVOFlag = NRVOFlag;
898 LTy = BuildByRefType(&D);
900 llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
901 Alloc->setName(D.getName());
903 CharUnits allocaAlignment = alignment;
905 allocaAlignment = std::max(allocaAlignment,
906 getContext().toCharUnitsFromBits(getTarget().getPointerAlign(0)));
907 Alloc->setAlignment(allocaAlignment.getQuantity());
910 // Emit a lifetime intrinsic if meaningful. There's no point
911 // in doing this if we don't have a valid insertion point (?).
912 uint64_t size = CGM.getDataLayout().getTypeAllocSize(LTy);
913 if (HaveInsertPoint() && shouldUseLifetimeMarkers(*this, D, size)) {
914 llvm::Value *sizeV = llvm::ConstantInt::get(Int64Ty, size);
916 emission.SizeForLifetimeMarkers = sizeV;
917 llvm::Value *castAddr = Builder.CreateBitCast(Alloc, Int8PtrTy);
918 Builder.CreateCall2(CGM.getLLVMLifetimeStartFn(), sizeV, castAddr)
921 assert(!emission.useLifetimeMarkers());
927 if (!DidCallStackSave) {
929 llvm::Value *Stack = CreateTempAlloca(Int8PtrTy, "saved_stack");
931 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
932 llvm::Value *V = Builder.CreateCall(F);
934 Builder.CreateStore(V, Stack);
936 DidCallStackSave = true;
938 // Push a cleanup block and restore the stack there.
939 // FIXME: in general circumstances, this should be an EH cleanup.
940 EHStack.pushCleanup<CallStackRestore>(NormalCleanup, Stack);
943 llvm::Value *elementCount;
944 QualType elementType;
945 llvm::tie(elementCount, elementType) = getVLASize(Ty);
947 llvm::Type *llvmTy = ConvertTypeForMem(elementType);
949 // Allocate memory for the array.
950 llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla");
951 vla->setAlignment(alignment.getQuantity());
956 llvm::Value *&DMEntry = LocalDeclMap[&D];
957 assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
959 emission.Address = DeclPtr;
961 // Emit debug info for local var declaration.
962 if (HaveInsertPoint())
963 if (CGDebugInfo *DI = getDebugInfo()) {
964 if (CGM.getCodeGenOpts().getDebugInfo()
965 >= CodeGenOptions::LimitedDebugInfo) {
966 DI->setLocation(D.getLocation());
967 DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
971 if (D.hasAttr<AnnotateAttr>())
972 EmitVarAnnotations(&D, emission.Address);
977 /// Determines whether the given __block variable is potentially
978 /// captured by the given expression.
979 static bool isCapturedBy(const VarDecl &var, const Expr *e) {
980 // Skip the most common kinds of expressions that make
981 // hierarchy-walking expensive.
982 e = e->IgnoreParenCasts();
984 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
985 const BlockDecl *block = be->getBlockDecl();
986 for (BlockDecl::capture_const_iterator i = block->capture_begin(),
987 e = block->capture_end(); i != e; ++i) {
988 if (i->getVariable() == &var)
992 // No need to walk into the subexpressions.
996 if (const StmtExpr *SE = dyn_cast<StmtExpr>(e)) {
997 const CompoundStmt *CS = SE->getSubStmt();
998 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
999 BE = CS->body_end(); BI != BE; ++BI)
1000 if (Expr *E = dyn_cast<Expr>((*BI))) {
1001 if (isCapturedBy(var, E))
1004 else if (DeclStmt *DS = dyn_cast<DeclStmt>((*BI))) {
1005 // special case declarations
1006 for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
1008 if (VarDecl *VD = dyn_cast<VarDecl>((*I))) {
1009 Expr *Init = VD->getInit();
1010 if (Init && isCapturedBy(var, Init))
1016 // FIXME. Make safe assumption assuming arbitrary statements cause capturing.
1017 // Later, provide code to poke into statements for capture analysis.
1022 for (Stmt::const_child_range children = e->children(); children; ++children)
1023 if (isCapturedBy(var, cast<Expr>(*children)))
1029 /// \brief Determine whether the given initializer is trivial in the sense
1030 /// that it requires no code to be generated.
1031 static bool isTrivialInitializer(const Expr *Init) {
1035 if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init))
1036 if (CXXConstructorDecl *Constructor = Construct->getConstructor())
1037 if (Constructor->isTrivial() &&
1038 Constructor->isDefaultConstructor() &&
1039 !Construct->requiresZeroInitialization())
1044 void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
1045 assert(emission.Variable && "emission was not valid!");
1047 // If this was emitted as a global constant, we're done.
1048 if (emission.wasEmittedAsGlobal()) return;
1050 const VarDecl &D = *emission.Variable;
1051 QualType type = D.getType();
1053 // If this local has an initializer, emit it now.
1054 const Expr *Init = D.getInit();
1056 // If we are at an unreachable point, we don't need to emit the initializer
1057 // unless it contains a label.
1058 if (!HaveInsertPoint()) {
1059 if (!Init || !ContainsLabel(Init)) return;
1060 EnsureInsertPoint();
1063 // Initialize the structure of a __block variable.
1064 if (emission.IsByRef)
1065 emitByrefStructureInit(emission);
1067 if (isTrivialInitializer(Init))
1070 CharUnits alignment = emission.Alignment;
1072 // Check whether this is a byref variable that's potentially
1073 // captured and moved by its own initializer. If so, we'll need to
1074 // emit the initializer first, then copy into the variable.
1075 bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init);
1078 capturedByInit ? emission.Address : emission.getObjectAddress(*this);
1080 llvm::Constant *constant = 0;
1081 if (emission.IsConstantAggregate) {
1082 assert(!capturedByInit && "constant init contains a capturing block?");
1083 constant = CGM.EmitConstantInit(D, this);
1087 LValue lv = MakeAddrLValue(Loc, type, alignment);
1089 return EmitExprAsInit(Init, &D, lv, capturedByInit);
1092 // If this is a simple aggregate initialization, we can optimize it
1094 bool isVolatile = type.isVolatileQualified();
1096 llvm::Value *SizeVal =
1097 llvm::ConstantInt::get(IntPtrTy,
1098 getContext().getTypeSizeInChars(type).getQuantity());
1100 llvm::Type *BP = Int8PtrTy;
1101 if (Loc->getType() != BP)
1102 Loc = Builder.CreateBitCast(Loc, BP);
1104 // If the initializer is all or mostly zeros, codegen with memset then do
1105 // a few stores afterward.
1106 if (shouldUseMemSetPlusStoresToInitialize(constant,
1107 CGM.getDataLayout().getTypeAllocSize(constant->getType()))) {
1108 Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal,
1109 alignment.getQuantity(), isVolatile);
1110 // Zero and undef don't require a stores.
1111 if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) {
1112 Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo());
1113 emitStoresForInitAfterMemset(constant, Loc, isVolatile, Builder);
1116 // Otherwise, create a temporary global with the initializer then
1117 // memcpy from the global to the alloca.
1118 std::string Name = GetStaticDeclName(*this, D, ".");
1119 llvm::GlobalVariable *GV =
1120 new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true,
1121 llvm::GlobalValue::PrivateLinkage,
1123 GV->setAlignment(alignment.getQuantity());
1124 GV->setUnnamedAddr(true);
1126 llvm::Value *SrcPtr = GV;
1127 if (SrcPtr->getType() != BP)
1128 SrcPtr = Builder.CreateBitCast(SrcPtr, BP);
1130 Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, alignment.getQuantity(),
1135 /// Emit an expression as an initializer for a variable at the given
1136 /// location. The expression is not necessarily the normal
1137 /// initializer for the variable, and the address is not necessarily
1138 /// its normal location.
1140 /// \param init the initializing expression
1141 /// \param var the variable to act as if we're initializing
1142 /// \param loc the address to initialize; its type is a pointer
1143 /// to the LLVM mapping of the variable's type
1144 /// \param alignment the alignment of the address
1145 /// \param capturedByInit true if the variable is a __block variable
1146 /// whose address is potentially changed by the initializer
1147 void CodeGenFunction::EmitExprAsInit(const Expr *init,
1150 bool capturedByInit) {
1151 QualType type = D->getType();
1153 if (type->isReferenceType()) {
1154 RValue rvalue = EmitReferenceBindingToExpr(init, D);
1156 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1157 EmitStoreThroughLValue(rvalue, lvalue, true);
1160 switch (getEvaluationKind(type)) {
1162 EmitScalarInit(init, D, lvalue, capturedByInit);
1165 ComplexPairTy complex = EmitComplexExpr(init);
1167 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1168 EmitStoreOfComplex(complex, lvalue, /*init*/ true);
1172 if (type->isAtomicType()) {
1173 EmitAtomicInit(const_cast<Expr*>(init), lvalue);
1175 // TODO: how can we delay here if D is captured by its initializer?
1176 EmitAggExpr(init, AggValueSlot::forLValue(lvalue,
1177 AggValueSlot::IsDestructed,
1178 AggValueSlot::DoesNotNeedGCBarriers,
1179 AggValueSlot::IsNotAliased));
1181 MaybeEmitStdInitializerListCleanup(lvalue.getAddress(), init);
1184 llvm_unreachable("bad evaluation kind");
1187 /// Enter a destroy cleanup for the given local variable.
1188 void CodeGenFunction::emitAutoVarTypeCleanup(
1189 const CodeGenFunction::AutoVarEmission &emission,
1190 QualType::DestructionKind dtorKind) {
1191 assert(dtorKind != QualType::DK_none);
1193 // Note that for __block variables, we want to destroy the
1194 // original stack object, not the possibly forwarded object.
1195 llvm::Value *addr = emission.getObjectAddress(*this);
1197 const VarDecl *var = emission.Variable;
1198 QualType type = var->getType();
1200 CleanupKind cleanupKind = NormalAndEHCleanup;
1201 CodeGenFunction::Destroyer *destroyer = 0;
1204 case QualType::DK_none:
1205 llvm_unreachable("no cleanup for trivially-destructible variable");
1207 case QualType::DK_cxx_destructor:
1208 // If there's an NRVO flag on the emission, we need a different
1210 if (emission.NRVOFlag) {
1211 assert(!type->isArrayType());
1212 CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor();
1213 EHStack.pushCleanup<DestroyNRVOVariable>(cleanupKind, addr, dtor,
1219 case QualType::DK_objc_strong_lifetime:
1220 // Suppress cleanups for pseudo-strong variables.
1221 if (var->isARCPseudoStrong()) return;
1223 // Otherwise, consider whether to use an EH cleanup or not.
1224 cleanupKind = getARCCleanupKind();
1226 // Use the imprecise destroyer by default.
1227 if (!var->hasAttr<ObjCPreciseLifetimeAttr>())
1228 destroyer = CodeGenFunction::destroyARCStrongImprecise;
1231 case QualType::DK_objc_weak_lifetime:
1235 // If we haven't chosen a more specific destroyer, use the default.
1236 if (!destroyer) destroyer = getDestroyer(dtorKind);
1238 // Use an EH cleanup in array destructors iff the destructor itself
1239 // is being pushed as an EH cleanup.
1240 bool useEHCleanup = (cleanupKind & EHCleanup);
1241 EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer,
1245 void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
1246 assert(emission.Variable && "emission was not valid!");
1248 // If this was emitted as a global constant, we're done.
1249 if (emission.wasEmittedAsGlobal()) return;
1251 // If we don't have an insertion point, we're done. Sema prevents
1252 // us from jumping into any of these scopes anyway.
1253 if (!HaveInsertPoint()) return;
1255 const VarDecl &D = *emission.Variable;
1257 // Make sure we call @llvm.lifetime.end. This needs to happen
1258 // *last*, so the cleanup needs to be pushed *first*.
1259 if (emission.useLifetimeMarkers()) {
1260 EHStack.pushCleanup<CallLifetimeEnd>(NormalCleanup,
1261 emission.getAllocatedAddress(),
1262 emission.getSizeForLifetimeMarkers());
1265 // Check the type for a cleanup.
1266 if (QualType::DestructionKind dtorKind = D.getType().isDestructedType())
1267 emitAutoVarTypeCleanup(emission, dtorKind);
1269 // In GC mode, honor objc_precise_lifetime.
1270 if (getLangOpts().getGC() != LangOptions::NonGC &&
1271 D.hasAttr<ObjCPreciseLifetimeAttr>()) {
1272 EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D);
1275 // Handle the cleanup attribute.
1276 if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
1277 const FunctionDecl *FD = CA->getFunctionDecl();
1279 llvm::Constant *F = CGM.GetAddrOfFunction(FD);
1280 assert(F && "Could not find function!");
1282 const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD);
1283 EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D);
1286 // If this is a block variable, call _Block_object_destroy
1287 // (on the unforwarded address).
1288 if (emission.IsByRef)
1289 enterByrefCleanup(emission);
1292 CodeGenFunction::Destroyer *
1293 CodeGenFunction::getDestroyer(QualType::DestructionKind kind) {
1295 case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor");
1296 case QualType::DK_cxx_destructor:
1297 return destroyCXXObject;
1298 case QualType::DK_objc_strong_lifetime:
1299 return destroyARCStrongPrecise;
1300 case QualType::DK_objc_weak_lifetime:
1301 return destroyARCWeak;
1303 llvm_unreachable("Unknown DestructionKind");
1306 /// pushEHDestroy - Push the standard destructor for the given type as
1307 /// an EH-only cleanup.
1308 void CodeGenFunction::pushEHDestroy(QualType::DestructionKind dtorKind,
1309 llvm::Value *addr, QualType type) {
1310 assert(dtorKind && "cannot push destructor for trivial type");
1311 assert(needsEHCleanup(dtorKind));
1313 pushDestroy(EHCleanup, addr, type, getDestroyer(dtorKind), true);
1316 /// pushDestroy - Push the standard destructor for the given type as
1317 /// at least a normal cleanup.
1318 void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind,
1319 llvm::Value *addr, QualType type) {
1320 assert(dtorKind && "cannot push destructor for trivial type");
1322 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1323 pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind),
1324 cleanupKind & EHCleanup);
1327 void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, llvm::Value *addr,
1328 QualType type, Destroyer *destroyer,
1329 bool useEHCleanupForArray) {
1330 pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type,
1331 destroyer, useEHCleanupForArray);
1334 /// emitDestroy - Immediately perform the destruction of the given
1337 /// \param addr - the address of the object; a type*
1338 /// \param type - the type of the object; if an array type, all
1339 /// objects are destroyed in reverse order
1340 /// \param destroyer - the function to call to destroy individual
1342 /// \param useEHCleanupForArray - whether an EH cleanup should be
1343 /// used when destroying array elements, in case one of the
1344 /// destructions throws an exception
1345 void CodeGenFunction::emitDestroy(llvm::Value *addr, QualType type,
1346 Destroyer *destroyer,
1347 bool useEHCleanupForArray) {
1348 const ArrayType *arrayType = getContext().getAsArrayType(type);
1350 return destroyer(*this, addr, type);
1352 llvm::Value *begin = addr;
1353 llvm::Value *length = emitArrayLength(arrayType, type, begin);
1355 // Normally we have to check whether the array is zero-length.
1356 bool checkZeroLength = true;
1358 // But if the array length is constant, we can suppress that.
1359 if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) {
1360 // ...and if it's constant zero, we can just skip the entire thing.
1361 if (constLength->isZero()) return;
1362 checkZeroLength = false;
1365 llvm::Value *end = Builder.CreateInBoundsGEP(begin, length);
1366 emitArrayDestroy(begin, end, type, destroyer,
1367 checkZeroLength, useEHCleanupForArray);
1370 /// emitArrayDestroy - Destroys all the elements of the given array,
1371 /// beginning from last to first. The array cannot be zero-length.
1373 /// \param begin - a type* denoting the first element of the array
1374 /// \param end - a type* denoting one past the end of the array
1375 /// \param type - the element type of the array
1376 /// \param destroyer - the function to call to destroy elements
1377 /// \param useEHCleanup - whether to push an EH cleanup to destroy
1378 /// the remaining elements in case the destruction of a single
1380 void CodeGenFunction::emitArrayDestroy(llvm::Value *begin,
1383 Destroyer *destroyer,
1384 bool checkZeroLength,
1385 bool useEHCleanup) {
1386 assert(!type->isArrayType());
1388 // The basic structure here is a do-while loop, because we don't
1389 // need to check for the zero-element case.
1390 llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body");
1391 llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done");
1393 if (checkZeroLength) {
1394 llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end,
1395 "arraydestroy.isempty");
1396 Builder.CreateCondBr(isEmpty, doneBB, bodyBB);
1399 // Enter the loop body, making that address the current address.
1400 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1402 llvm::PHINode *elementPast =
1403 Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast");
1404 elementPast->addIncoming(end, entryBB);
1406 // Shift the address back by one element.
1407 llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true);
1408 llvm::Value *element = Builder.CreateInBoundsGEP(elementPast, negativeOne,
1409 "arraydestroy.element");
1412 pushRegularPartialArrayCleanup(begin, element, type, destroyer);
1414 // Perform the actual destruction there.
1415 destroyer(*this, element, type);
1420 // Check whether we've reached the end.
1421 llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done");
1422 Builder.CreateCondBr(done, doneBB, bodyBB);
1423 elementPast->addIncoming(element, Builder.GetInsertBlock());
1429 /// Perform partial array destruction as if in an EH cleanup. Unlike
1430 /// emitArrayDestroy, the element type here may still be an array type.
1431 static void emitPartialArrayDestroy(CodeGenFunction &CGF,
1432 llvm::Value *begin, llvm::Value *end,
1434 CodeGenFunction::Destroyer *destroyer) {
1435 // If the element type is itself an array, drill down.
1436 unsigned arrayDepth = 0;
1437 while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) {
1438 // VLAs don't require a GEP index to walk into.
1439 if (!isa<VariableArrayType>(arrayType))
1441 type = arrayType->getElementType();
1445 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, arrayDepth+1);
1447 SmallVector<llvm::Value*,4> gepIndices(arrayDepth, zero);
1448 begin = CGF.Builder.CreateInBoundsGEP(begin, gepIndices, "pad.arraybegin");
1449 end = CGF.Builder.CreateInBoundsGEP(end, gepIndices, "pad.arrayend");
1452 // Destroy the array. We don't ever need an EH cleanup because we
1453 // assume that we're in an EH cleanup ourselves, so a throwing
1454 // destructor causes an immediate terminate.
1455 CGF.emitArrayDestroy(begin, end, type, destroyer,
1456 /*checkZeroLength*/ true, /*useEHCleanup*/ false);
1460 /// RegularPartialArrayDestroy - a cleanup which performs a partial
1461 /// array destroy where the end pointer is regularly determined and
1462 /// does not need to be loaded from a local.
1463 class RegularPartialArrayDestroy : public EHScopeStack::Cleanup {
1464 llvm::Value *ArrayBegin;
1465 llvm::Value *ArrayEnd;
1466 QualType ElementType;
1467 CodeGenFunction::Destroyer *Destroyer;
1469 RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd,
1470 QualType elementType,
1471 CodeGenFunction::Destroyer *destroyer)
1472 : ArrayBegin(arrayBegin), ArrayEnd(arrayEnd),
1473 ElementType(elementType), Destroyer(destroyer) {}
1475 void Emit(CodeGenFunction &CGF, Flags flags) {
1476 emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd,
1477 ElementType, Destroyer);
1481 /// IrregularPartialArrayDestroy - a cleanup which performs a
1482 /// partial array destroy where the end pointer is irregularly
1483 /// determined and must be loaded from a local.
1484 class IrregularPartialArrayDestroy : public EHScopeStack::Cleanup {
1485 llvm::Value *ArrayBegin;
1486 llvm::Value *ArrayEndPointer;
1487 QualType ElementType;
1488 CodeGenFunction::Destroyer *Destroyer;
1490 IrregularPartialArrayDestroy(llvm::Value *arrayBegin,
1491 llvm::Value *arrayEndPointer,
1492 QualType elementType,
1493 CodeGenFunction::Destroyer *destroyer)
1494 : ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer),
1495 ElementType(elementType), Destroyer(destroyer) {}
1497 void Emit(CodeGenFunction &CGF, Flags flags) {
1498 llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer);
1499 emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd,
1500 ElementType, Destroyer);
1505 /// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy
1506 /// already-constructed elements of the given array. The cleanup
1507 /// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1509 /// \param elementType - the immediate element type of the array;
1510 /// possibly still an array type
1511 void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
1512 llvm::Value *arrayEndPointer,
1513 QualType elementType,
1514 Destroyer *destroyer) {
1515 pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup,
1516 arrayBegin, arrayEndPointer,
1517 elementType, destroyer);
1520 /// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
1521 /// already-constructed elements of the given array. The cleanup
1522 /// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1524 /// \param elementType - the immediate element type of the array;
1525 /// possibly still an array type
1526 void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin,
1527 llvm::Value *arrayEnd,
1528 QualType elementType,
1529 Destroyer *destroyer) {
1530 pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup,
1531 arrayBegin, arrayEnd,
1532 elementType, destroyer);
1535 /// Lazily declare the @llvm.lifetime.start intrinsic.
1536 llvm::Constant *CodeGenModule::getLLVMLifetimeStartFn() {
1537 if (LifetimeStartFn) return LifetimeStartFn;
1538 LifetimeStartFn = llvm::Intrinsic::getDeclaration(&getModule(),
1539 llvm::Intrinsic::lifetime_start);
1540 return LifetimeStartFn;
1543 /// Lazily declare the @llvm.lifetime.end intrinsic.
1544 llvm::Constant *CodeGenModule::getLLVMLifetimeEndFn() {
1545 if (LifetimeEndFn) return LifetimeEndFn;
1546 LifetimeEndFn = llvm::Intrinsic::getDeclaration(&getModule(),
1547 llvm::Intrinsic::lifetime_end);
1548 return LifetimeEndFn;
1552 /// A cleanup to perform a release of an object at the end of a
1553 /// function. This is used to balance out the incoming +1 of a
1554 /// ns_consumed argument when we can't reasonably do that just by
1555 /// not doing the initial retain for a __block argument.
1556 struct ConsumeARCParameter : EHScopeStack::Cleanup {
1557 ConsumeARCParameter(llvm::Value *param,
1558 ARCPreciseLifetime_t precise)
1559 : Param(param), Precise(precise) {}
1562 ARCPreciseLifetime_t Precise;
1564 void Emit(CodeGenFunction &CGF, Flags flags) {
1565 CGF.EmitARCRelease(Param, Precise);
1570 /// Emit an alloca (or GlobalValue depending on target)
1571 /// for the specified parameter and set up LocalDeclMap.
1572 void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
1574 // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
1575 assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
1576 "Invalid argument to EmitParmDecl");
1578 Arg->setName(D.getName());
1580 QualType Ty = D.getType();
1582 // Use better IR generation for certain implicit parameters.
1583 if (isa<ImplicitParamDecl>(D)) {
1584 // The only implicit argument a block has is its literal.
1586 LocalDeclMap[&D] = Arg;
1587 llvm::Value *LocalAddr = 0;
1588 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1589 // Allocate a stack slot to let the debug info survive the RA.
1590 llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1591 D.getName() + ".addr");
1592 Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity());
1593 LValue lv = MakeAddrLValue(Alloc, Ty, getContext().getDeclAlign(&D));
1594 EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1595 LocalAddr = Builder.CreateLoad(Alloc);
1598 if (CGDebugInfo *DI = getDebugInfo()) {
1599 if (CGM.getCodeGenOpts().getDebugInfo()
1600 >= CodeGenOptions::LimitedDebugInfo) {
1601 DI->setLocation(D.getLocation());
1602 DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, Arg, LocalAddr, Builder);
1610 llvm::Value *DeclPtr;
1611 // If this is an aggregate or variable sized value, reuse the input pointer.
1612 if (!Ty->isConstantSizeType() ||
1613 !CodeGenFunction::hasScalarEvaluationKind(Ty)) {
1616 // Otherwise, create a temporary to hold the value.
1617 llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1618 D.getName() + ".addr");
1619 CharUnits Align = getContext().getDeclAlign(&D);
1620 Alloc->setAlignment(Align.getQuantity());
1623 bool doStore = true;
1625 Qualifiers qs = Ty.getQualifiers();
1626 LValue lv = MakeAddrLValue(DeclPtr, Ty, Align);
1627 if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) {
1628 // We honor __attribute__((ns_consumed)) for types with lifetime.
1629 // For __strong, it's handled by just skipping the initial retain;
1630 // otherwise we have to balance out the initial +1 with an extra
1631 // cleanup to do the release at the end of the function.
1632 bool isConsumed = D.hasAttr<NSConsumedAttr>();
1634 // 'self' is always formally __strong, but if this is not an
1635 // init method then we don't want to retain it.
1636 if (D.isARCPseudoStrong()) {
1637 const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CurCodeDecl);
1638 assert(&D == method->getSelfDecl());
1639 assert(lt == Qualifiers::OCL_Strong);
1640 assert(qs.hasConst());
1641 assert(method->getMethodFamily() != OMF_init);
1643 lt = Qualifiers::OCL_ExplicitNone;
1646 if (lt == Qualifiers::OCL_Strong) {
1648 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1649 // use objc_storeStrong(&dest, value) for retaining the
1650 // object. But first, store a null into 'dest' because
1651 // objc_storeStrong attempts to release its old value.
1652 llvm::Value * Null = CGM.EmitNullConstant(D.getType());
1653 EmitStoreOfScalar(Null, lv, /* isInitialization */ true);
1654 EmitARCStoreStrongCall(lv.getAddress(), Arg, true);
1658 // Don't use objc_retainBlock for block pointers, because we
1659 // don't want to Block_copy something just because we got it
1661 Arg = EmitARCRetainNonBlock(Arg);
1664 // Push the cleanup for a consumed parameter.
1666 ARCPreciseLifetime_t precise = (D.hasAttr<ObjCPreciseLifetimeAttr>()
1667 ? ARCPreciseLifetime : ARCImpreciseLifetime);
1668 EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), Arg,
1672 if (lt == Qualifiers::OCL_Weak) {
1673 EmitARCInitWeak(DeclPtr, Arg);
1674 doStore = false; // The weak init is a store, no need to do two.
1678 // Enter the cleanup scope.
1679 EmitAutoVarWithLifetime(*this, D, DeclPtr, lt);
1682 // Store the initial value into the alloca.
1684 EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1687 llvm::Value *&DMEntry = LocalDeclMap[&D];
1688 assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
1691 // Emit debug info for param declaration.
1692 if (CGDebugInfo *DI = getDebugInfo()) {
1693 if (CGM.getCodeGenOpts().getDebugInfo()
1694 >= CodeGenOptions::LimitedDebugInfo) {
1695 DI->EmitDeclareOfArgVariable(&D, DeclPtr, ArgNo, Builder);
1699 if (D.hasAttr<AnnotateAttr>())
1700 EmitVarAnnotations(&D, DeclPtr);