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 "CGCleanup.h"
16 #include "CGDebugInfo.h"
17 #include "CGOpenCLRuntime.h"
18 #include "CodeGenModule.h"
19 #include "clang/AST/ASTContext.h"
20 #include "clang/AST/CharUnits.h"
21 #include "clang/AST/Decl.h"
22 #include "clang/AST/DeclObjC.h"
23 #include "clang/Basic/SourceManager.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "clang/CodeGen/CGFunctionInfo.h"
26 #include "clang/Frontend/CodeGenOptions.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/GlobalVariable.h"
29 #include "llvm/IR/Intrinsics.h"
30 #include "llvm/IR/Type.h"
31 using namespace clang;
32 using namespace CodeGen;
35 void CodeGenFunction::EmitDecl(const Decl &D) {
36 switch (D.getKind()) {
37 case Decl::TranslationUnit:
38 case Decl::ExternCContext:
40 case Decl::UnresolvedUsingTypename:
41 case Decl::ClassTemplateSpecialization:
42 case Decl::ClassTemplatePartialSpecialization:
43 case Decl::VarTemplateSpecialization:
44 case Decl::VarTemplatePartialSpecialization:
45 case Decl::TemplateTypeParm:
46 case Decl::UnresolvedUsingValue:
47 case Decl::NonTypeTemplateParm:
49 case Decl::CXXConstructor:
50 case Decl::CXXDestructor:
51 case Decl::CXXConversion:
53 case Decl::MSProperty:
54 case Decl::IndirectField:
56 case Decl::ObjCAtDefsField:
58 case Decl::ImplicitParam:
59 case Decl::ClassTemplate:
60 case Decl::VarTemplate:
61 case Decl::FunctionTemplate:
62 case Decl::TypeAliasTemplate:
63 case Decl::TemplateTemplateParm:
64 case Decl::ObjCMethod:
65 case Decl::ObjCCategory:
66 case Decl::ObjCProtocol:
67 case Decl::ObjCInterface:
68 case Decl::ObjCCategoryImpl:
69 case Decl::ObjCImplementation:
70 case Decl::ObjCProperty:
71 case Decl::ObjCCompatibleAlias:
72 case Decl::AccessSpec:
73 case Decl::LinkageSpec:
74 case Decl::ObjCPropertyImpl:
75 case Decl::FileScopeAsm:
77 case Decl::FriendTemplate:
80 case Decl::ClassScopeFunctionSpecialization:
81 case Decl::UsingShadow:
82 llvm_unreachable("Declaration should not be in declstmts!");
83 case Decl::Function: // void X();
84 case Decl::Record: // struct/union/class X;
85 case Decl::Enum: // enum X;
86 case Decl::EnumConstant: // enum ? { X = ? }
87 case Decl::CXXRecord: // struct/union/class X; [C++]
88 case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
89 case Decl::Label: // __label__ x;
91 case Decl::OMPThreadPrivate:
93 // None of these decls require codegen support.
96 case Decl::NamespaceAlias:
97 if (CGDebugInfo *DI = getDebugInfo())
98 DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D));
100 case Decl::Using: // using X; [C++]
101 if (CGDebugInfo *DI = getDebugInfo())
102 DI->EmitUsingDecl(cast<UsingDecl>(D));
104 case Decl::UsingDirective: // using namespace X; [C++]
105 if (CGDebugInfo *DI = getDebugInfo())
106 DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D));
109 const VarDecl &VD = cast<VarDecl>(D);
110 assert(VD.isLocalVarDecl() &&
111 "Should not see file-scope variables inside a function!");
112 return EmitVarDecl(VD);
115 case Decl::Typedef: // typedef int X;
116 case Decl::TypeAlias: { // using X = int; [C++0x]
117 const TypedefNameDecl &TD = cast<TypedefNameDecl>(D);
118 QualType Ty = TD.getUnderlyingType();
120 if (Ty->isVariablyModifiedType())
121 EmitVariablyModifiedType(Ty);
126 /// EmitVarDecl - This method handles emission of any variable declaration
127 /// inside a function, including static vars etc.
128 void CodeGenFunction::EmitVarDecl(const VarDecl &D) {
129 if (D.isStaticLocal()) {
130 llvm::GlobalValue::LinkageTypes Linkage =
131 CGM.getLLVMLinkageVarDefinition(&D, /*isConstant=*/false);
133 // FIXME: We need to force the emission/use of a guard variable for
134 // some variables even if we can constant-evaluate them because
135 // we can't guarantee every translation unit will constant-evaluate them.
137 return EmitStaticVarDecl(D, Linkage);
140 if (D.hasExternalStorage())
141 // Don't emit it now, allow it to be emitted lazily on its first use.
144 if (D.getStorageClass() == SC_OpenCLWorkGroupLocal)
145 return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D);
147 assert(D.hasLocalStorage());
148 return EmitAutoVarDecl(D);
151 static std::string getStaticDeclName(CodeGenModule &CGM, const VarDecl &D) {
152 if (CGM.getLangOpts().CPlusPlus)
153 return CGM.getMangledName(&D).str();
155 // If this isn't C++, we don't need a mangled name, just a pretty one.
156 assert(!D.isExternallyVisible() && "name shouldn't matter");
157 std::string ContextName;
158 const DeclContext *DC = D.getDeclContext();
159 if (auto *CD = dyn_cast<CapturedDecl>(DC))
160 DC = cast<DeclContext>(CD->getNonClosureContext());
161 if (const auto *FD = dyn_cast<FunctionDecl>(DC))
162 ContextName = CGM.getMangledName(FD);
163 else if (const auto *BD = dyn_cast<BlockDecl>(DC))
164 ContextName = CGM.getBlockMangledName(GlobalDecl(), BD);
165 else if (const auto *OMD = dyn_cast<ObjCMethodDecl>(DC))
166 ContextName = OMD->getSelector().getAsString();
168 llvm_unreachable("Unknown context for static var decl");
170 ContextName += "." + D.getNameAsString();
174 llvm::Constant *CodeGenModule::getOrCreateStaticVarDecl(
175 const VarDecl &D, llvm::GlobalValue::LinkageTypes Linkage) {
176 // In general, we don't always emit static var decls once before we reference
177 // them. It is possible to reference them before emitting the function that
178 // contains them, and it is possible to emit the containing function multiple
180 if (llvm::Constant *ExistingGV = StaticLocalDeclMap[&D])
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 = getMangledName(&D);
191 Name = getStaticDeclName(*this, D);
193 llvm::Type *LTy = getTypes().ConvertTypeForMem(Ty);
195 GetGlobalVarAddressSpace(&D, getContext().getTargetAddressSpace(Ty));
197 // Local address space cannot have an initializer.
198 llvm::Constant *Init = nullptr;
199 if (Ty.getAddressSpace() != LangAS::opencl_local)
200 Init = EmitNullConstant(Ty);
202 Init = llvm::UndefValue::get(LTy);
204 llvm::GlobalVariable *GV =
205 new llvm::GlobalVariable(getModule(), LTy,
206 Ty.isConstant(getContext()), Linkage,
208 llvm::GlobalVariable::NotThreadLocal,
210 GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
211 setGlobalVisibility(GV, &D);
213 if (supportsCOMDAT() && GV->isWeakForLinker())
214 GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
219 if (D.isExternallyVisible()) {
220 if (D.hasAttr<DLLImportAttr>())
221 GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
222 else if (D.hasAttr<DLLExportAttr>())
223 GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
226 // Make sure the result is of the correct type.
227 unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(Ty);
228 llvm::Constant *Addr = GV;
229 if (AddrSpace != ExpectedAddrSpace) {
230 llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
231 Addr = llvm::ConstantExpr::getAddrSpaceCast(GV, PTy);
234 setStaticLocalDeclAddress(&D, Addr);
236 // Ensure that the static local gets initialized by making sure the parent
237 // function gets emitted eventually.
238 const Decl *DC = cast<Decl>(D.getDeclContext());
240 // We can't name blocks or captured statements directly, so try to emit their
242 if (isa<BlockDecl>(DC) || isa<CapturedDecl>(DC)) {
243 DC = DC->getNonClosureContext();
244 // FIXME: Ensure that global blocks get emitted.
250 if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
251 GD = GlobalDecl(CD, Ctor_Base);
252 else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
253 GD = GlobalDecl(DD, Dtor_Base);
254 else if (const auto *FD = dyn_cast<FunctionDecl>(DC))
257 // Don't do anything for Obj-C method decls or global closures. We should
259 assert(isa<ObjCMethodDecl>(DC) && "unexpected parent code decl");
262 (void)GetAddrOfGlobal(GD);
267 /// hasNontrivialDestruction - Determine whether a type's destruction is
268 /// non-trivial. If so, and the variable uses static initialization, we must
269 /// register its destructor to run on exit.
270 static bool hasNontrivialDestruction(QualType T) {
271 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
272 return RD && !RD->hasTrivialDestructor();
275 /// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the
276 /// global variable that has already been created for it. If the initializer
277 /// has a different type than GV does, this may free GV and return a different
278 /// one. Otherwise it just returns GV.
279 llvm::GlobalVariable *
280 CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
281 llvm::GlobalVariable *GV) {
282 llvm::Constant *Init = CGM.EmitConstantInit(D, this);
284 // If constant emission failed, then this should be a C++ static
287 if (!getLangOpts().CPlusPlus)
288 CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
289 else if (Builder.GetInsertBlock()) {
290 // Since we have a static initializer, this global variable can't
292 GV->setConstant(false);
294 EmitCXXGuardedInit(D, GV, /*PerformInit*/true);
299 // The initializer may differ in type from the global. Rewrite
300 // the global to match the initializer. (We have to do this
301 // because some types, like unions, can't be completely represented
302 // in the LLVM type system.)
303 if (GV->getType()->getElementType() != Init->getType()) {
304 llvm::GlobalVariable *OldGV = GV;
306 GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
308 OldGV->getLinkage(), Init, "",
309 /*InsertBefore*/ OldGV,
310 OldGV->getThreadLocalMode(),
311 CGM.getContext().getTargetAddressSpace(D.getType()));
312 GV->setVisibility(OldGV->getVisibility());
314 // Steal the name of the old global
317 // Replace all uses of the old global with the new global
318 llvm::Constant *NewPtrForOldDecl =
319 llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
320 OldGV->replaceAllUsesWith(NewPtrForOldDecl);
322 // Erase the old global, since it is no longer used.
323 OldGV->eraseFromParent();
326 GV->setConstant(CGM.isTypeConstant(D.getType(), true));
327 GV->setInitializer(Init);
329 if (hasNontrivialDestruction(D.getType())) {
330 // We have a constant initializer, but a nontrivial destructor. We still
331 // need to perform a guarded "initialization" in order to register the
333 EmitCXXGuardedInit(D, GV, /*PerformInit*/false);
339 void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
340 llvm::GlobalValue::LinkageTypes Linkage) {
341 llvm::Value *&DMEntry = LocalDeclMap[&D];
342 assert(!DMEntry && "Decl already exists in localdeclmap!");
344 // Check to see if we already have a global variable for this
345 // declaration. This can happen when double-emitting function
346 // bodies, e.g. with complete and base constructors.
347 llvm::Constant *addr = CGM.getOrCreateStaticVarDecl(D, Linkage);
349 // Store into LocalDeclMap before generating initializer to handle
350 // circular references.
353 // We can't have a VLA here, but we can have a pointer to a VLA,
354 // even though that doesn't really make any sense.
355 // Make sure to evaluate VLA bounds now so that we have them for later.
356 if (D.getType()->isVariablyModifiedType())
357 EmitVariablyModifiedType(D.getType());
359 // Save the type in case adding the initializer forces a type change.
360 llvm::Type *expectedType = addr->getType();
362 llvm::GlobalVariable *var =
363 cast<llvm::GlobalVariable>(addr->stripPointerCasts());
364 // If this value has an initializer, emit it.
366 var = AddInitializerToStaticVarDecl(D, var);
368 var->setAlignment(getContext().getDeclAlign(&D).getQuantity());
370 if (D.hasAttr<AnnotateAttr>())
371 CGM.AddGlobalAnnotations(&D, var);
373 if (const SectionAttr *SA = D.getAttr<SectionAttr>())
374 var->setSection(SA->getName());
376 if (D.hasAttr<UsedAttr>())
377 CGM.addUsedGlobal(var);
379 // We may have to cast the constant because of the initializer
382 // FIXME: It is really dangerous to store this in the map; if anyone
383 // RAUW's the GV uses of this constant will be invalid.
384 llvm::Constant *castedAddr =
385 llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(var, expectedType);
386 DMEntry = castedAddr;
387 CGM.setStaticLocalDeclAddress(&D, castedAddr);
389 CGM.getSanitizerMetadata()->reportGlobalToASan(var, D);
391 // Emit global variable debug descriptor for static vars.
392 CGDebugInfo *DI = getDebugInfo();
394 CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) {
395 DI->setLocation(D.getLocation());
396 DI->EmitGlobalVariable(var, &D);
401 struct DestroyObject : EHScopeStack::Cleanup {
402 DestroyObject(llvm::Value *addr, QualType type,
403 CodeGenFunction::Destroyer *destroyer,
404 bool useEHCleanupForArray)
405 : addr(addr), type(type), destroyer(destroyer),
406 useEHCleanupForArray(useEHCleanupForArray) {}
410 CodeGenFunction::Destroyer *destroyer;
411 bool useEHCleanupForArray;
413 void Emit(CodeGenFunction &CGF, Flags flags) override {
414 // Don't use an EH cleanup recursively from an EH cleanup.
415 bool useEHCleanupForArray =
416 flags.isForNormalCleanup() && this->useEHCleanupForArray;
418 CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray);
422 struct DestroyNRVOVariable : EHScopeStack::Cleanup {
423 DestroyNRVOVariable(llvm::Value *addr,
424 const CXXDestructorDecl *Dtor,
425 llvm::Value *NRVOFlag)
426 : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(addr) {}
428 const CXXDestructorDecl *Dtor;
429 llvm::Value *NRVOFlag;
432 void Emit(CodeGenFunction &CGF, Flags flags) override {
433 // Along the exceptions path we always execute the dtor.
434 bool NRVO = flags.isForNormalCleanup() && NRVOFlag;
436 llvm::BasicBlock *SkipDtorBB = nullptr;
438 // If we exited via NRVO, we skip the destructor call.
439 llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused");
440 SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor");
441 llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val");
442 CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB);
443 CGF.EmitBlock(RunDtorBB);
446 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
447 /*ForVirtualBase=*/false,
448 /*Delegating=*/false,
451 if (NRVO) CGF.EmitBlock(SkipDtorBB);
455 struct CallStackRestore : EHScopeStack::Cleanup {
457 CallStackRestore(llvm::Value *Stack) : Stack(Stack) {}
458 void Emit(CodeGenFunction &CGF, Flags flags) override {
459 llvm::Value *V = CGF.Builder.CreateLoad(Stack);
460 llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
461 CGF.Builder.CreateCall(F, V);
465 struct ExtendGCLifetime : EHScopeStack::Cleanup {
467 ExtendGCLifetime(const VarDecl *var) : Var(*var) {}
469 void Emit(CodeGenFunction &CGF, Flags flags) override {
470 // Compute the address of the local variable, in case it's a
471 // byref or something.
472 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
473 Var.getType(), VK_LValue, SourceLocation());
474 llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE),
476 CGF.EmitExtendGCLifetime(value);
480 struct CallCleanupFunction : EHScopeStack::Cleanup {
481 llvm::Constant *CleanupFn;
482 const CGFunctionInfo &FnInfo;
485 CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
487 : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {}
489 void Emit(CodeGenFunction &CGF, Flags flags) override {
490 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
491 Var.getType(), VK_LValue, SourceLocation());
492 // Compute the address of the local variable, in case it's a byref
494 llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getAddress();
496 // In some cases, the type of the function argument will be different from
497 // the type of the pointer. An example of this is
498 // void f(void* arg);
499 // __attribute__((cleanup(f))) void *g;
501 // To fix this we insert a bitcast here.
502 QualType ArgTy = FnInfo.arg_begin()->type;
504 CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy));
507 Args.add(RValue::get(Arg),
508 CGF.getContext().getPointerType(Var.getType()));
509 CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args);
513 /// A cleanup to call @llvm.lifetime.end.
514 class CallLifetimeEnd : public EHScopeStack::Cleanup {
518 CallLifetimeEnd(llvm::Value *addr, llvm::Value *size)
519 : Addr(addr), Size(size) {}
521 void Emit(CodeGenFunction &CGF, Flags flags) override {
522 CGF.EmitLifetimeEnd(Size, Addr);
527 /// EmitAutoVarWithLifetime - Does the setup required for an automatic
528 /// variable with lifetime.
529 static void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var,
531 Qualifiers::ObjCLifetime lifetime) {
533 case Qualifiers::OCL_None:
534 llvm_unreachable("present but none");
536 case Qualifiers::OCL_ExplicitNone:
540 case Qualifiers::OCL_Strong: {
541 CodeGenFunction::Destroyer *destroyer =
542 (var.hasAttr<ObjCPreciseLifetimeAttr>()
543 ? CodeGenFunction::destroyARCStrongPrecise
544 : CodeGenFunction::destroyARCStrongImprecise);
546 CleanupKind cleanupKind = CGF.getARCCleanupKind();
547 CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer,
548 cleanupKind & EHCleanup);
551 case Qualifiers::OCL_Autoreleasing:
555 case Qualifiers::OCL_Weak:
556 // __weak objects always get EH cleanups; otherwise, exceptions
557 // could cause really nasty crashes instead of mere leaks.
558 CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(),
559 CodeGenFunction::destroyARCWeak,
560 /*useEHCleanup*/ true);
565 static bool isAccessedBy(const VarDecl &var, const Stmt *s) {
566 if (const Expr *e = dyn_cast<Expr>(s)) {
567 // Skip the most common kinds of expressions that make
568 // hierarchy-walking expensive.
569 s = e = e->IgnoreParenCasts();
571 if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e))
572 return (ref->getDecl() == &var);
573 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
574 const BlockDecl *block = be->getBlockDecl();
575 for (const auto &I : block->captures()) {
576 if (I.getVariable() == &var)
582 for (const Stmt *SubStmt : s->children())
583 // SubStmt might be null; as in missing decl or conditional of an if-stmt.
584 if (SubStmt && isAccessedBy(var, SubStmt))
590 static bool isAccessedBy(const ValueDecl *decl, const Expr *e) {
591 if (!decl) return false;
592 if (!isa<VarDecl>(decl)) return false;
593 const VarDecl *var = cast<VarDecl>(decl);
594 return isAccessedBy(*var, e);
597 static void drillIntoBlockVariable(CodeGenFunction &CGF,
599 const VarDecl *var) {
600 lvalue.setAddress(CGF.BuildBlockByrefAddress(lvalue.getAddress(), var));
603 void CodeGenFunction::EmitScalarInit(const Expr *init, const ValueDecl *D,
604 LValue lvalue, bool capturedByInit) {
605 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
607 llvm::Value *value = EmitScalarExpr(init);
609 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
610 EmitStoreThroughLValue(RValue::get(value), lvalue, true);
614 if (const CXXDefaultInitExpr *DIE = dyn_cast<CXXDefaultInitExpr>(init))
615 init = DIE->getExpr();
617 // If we're emitting a value with lifetime, we have to do the
618 // initialization *before* we leave the cleanup scopes.
619 if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) {
620 enterFullExpression(ewc);
621 init = ewc->getSubExpr();
623 CodeGenFunction::RunCleanupsScope Scope(*this);
625 // We have to maintain the illusion that the variable is
626 // zero-initialized. If the variable might be accessed in its
627 // initializer, zero-initialize before running the initializer, then
628 // actually perform the initialization with an assign.
629 bool accessedByInit = false;
630 if (lifetime != Qualifiers::OCL_ExplicitNone)
631 accessedByInit = (capturedByInit || isAccessedBy(D, init));
632 if (accessedByInit) {
633 LValue tempLV = lvalue;
634 // Drill down to the __block object if necessary.
635 if (capturedByInit) {
636 // We can use a simple GEP for this because it can't have been
638 tempLV.setAddress(Builder.CreateStructGEP(
639 nullptr, tempLV.getAddress(),
640 getByRefValueLLVMField(cast<VarDecl>(D)).second));
643 llvm::PointerType *ty
644 = cast<llvm::PointerType>(tempLV.getAddress()->getType());
645 ty = cast<llvm::PointerType>(ty->getElementType());
647 llvm::Value *zero = llvm::ConstantPointerNull::get(ty);
649 // If __weak, we want to use a barrier under certain conditions.
650 if (lifetime == Qualifiers::OCL_Weak)
651 EmitARCInitWeak(tempLV.getAddress(), zero);
653 // Otherwise just do a simple store.
655 EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true);
658 // Emit the initializer.
659 llvm::Value *value = nullptr;
662 case Qualifiers::OCL_None:
663 llvm_unreachable("present but none");
665 case Qualifiers::OCL_ExplicitNone:
667 value = EmitScalarExpr(init);
670 case Qualifiers::OCL_Strong: {
671 value = EmitARCRetainScalarExpr(init);
675 case Qualifiers::OCL_Weak: {
676 // No way to optimize a producing initializer into this. It's not
677 // worth optimizing for, because the value will immediately
678 // disappear in the common case.
679 value = EmitScalarExpr(init);
681 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
683 EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true);
685 EmitARCInitWeak(lvalue.getAddress(), value);
689 case Qualifiers::OCL_Autoreleasing:
690 value = EmitARCRetainAutoreleaseScalarExpr(init);
694 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
696 // If the variable might have been accessed by its initializer, we
697 // might have to initialize with a barrier. We have to do this for
698 // both __weak and __strong, but __weak got filtered out above.
699 if (accessedByInit && lifetime == Qualifiers::OCL_Strong) {
700 llvm::Value *oldValue = EmitLoadOfScalar(lvalue, init->getExprLoc());
701 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
702 EmitARCRelease(oldValue, ARCImpreciseLifetime);
706 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
709 /// EmitScalarInit - Initialize the given lvalue with the given object.
710 void CodeGenFunction::EmitScalarInit(llvm::Value *init, LValue lvalue) {
711 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
713 return EmitStoreThroughLValue(RValue::get(init), lvalue, true);
716 case Qualifiers::OCL_None:
717 llvm_unreachable("present but none");
719 case Qualifiers::OCL_ExplicitNone:
723 case Qualifiers::OCL_Strong:
724 init = EmitARCRetain(lvalue.getType(), init);
727 case Qualifiers::OCL_Weak:
728 // Initialize and then skip the primitive store.
729 EmitARCInitWeak(lvalue.getAddress(), init);
732 case Qualifiers::OCL_Autoreleasing:
733 init = EmitARCRetainAutorelease(lvalue.getType(), init);
737 EmitStoreOfScalar(init, lvalue, /* isInitialization */ true);
740 /// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the
741 /// non-zero parts of the specified initializer with equal or fewer than
742 /// NumStores scalar stores.
743 static bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init,
744 unsigned &NumStores) {
745 // Zero and Undef never requires any extra stores.
746 if (isa<llvm::ConstantAggregateZero>(Init) ||
747 isa<llvm::ConstantPointerNull>(Init) ||
748 isa<llvm::UndefValue>(Init))
750 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
751 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
752 isa<llvm::ConstantExpr>(Init))
753 return Init->isNullValue() || NumStores--;
755 // See if we can emit each element.
756 if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) {
757 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
758 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
759 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
765 if (llvm::ConstantDataSequential *CDS =
766 dyn_cast<llvm::ConstantDataSequential>(Init)) {
767 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
768 llvm::Constant *Elt = CDS->getElementAsConstant(i);
769 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
775 // Anything else is hard and scary.
779 /// emitStoresForInitAfterMemset - For inits that
780 /// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar
781 /// stores that would be required.
782 static void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc,
783 bool isVolatile, CGBuilderTy &Builder) {
784 assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) &&
785 "called emitStoresForInitAfterMemset for zero or undef value.");
787 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
788 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
789 isa<llvm::ConstantExpr>(Init)) {
790 Builder.CreateStore(Init, Loc, isVolatile);
794 if (llvm::ConstantDataSequential *CDS =
795 dyn_cast<llvm::ConstantDataSequential>(Init)) {
796 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
797 llvm::Constant *Elt = CDS->getElementAsConstant(i);
799 // If necessary, get a pointer to the element and emit it.
800 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
801 emitStoresForInitAfterMemset(
802 Elt, Builder.CreateConstGEP2_32(Init->getType(), Loc, 0, i),
803 isVolatile, Builder);
808 assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) &&
809 "Unknown value type!");
811 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
812 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
814 // If necessary, get a pointer to the element and emit it.
815 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
816 emitStoresForInitAfterMemset(
817 Elt, Builder.CreateConstGEP2_32(Init->getType(), Loc, 0, i),
818 isVolatile, Builder);
823 /// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset
824 /// plus some stores to initialize a local variable instead of using a memcpy
825 /// from a constant global. It is beneficial to use memset if the global is all
826 /// zeros, or mostly zeros and large.
827 static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init,
828 uint64_t GlobalSize) {
829 // If a global is all zeros, always use a memset.
830 if (isa<llvm::ConstantAggregateZero>(Init)) return true;
832 // If a non-zero global is <= 32 bytes, always use a memcpy. If it is large,
833 // do it if it will require 6 or fewer scalar stores.
834 // TODO: Should budget depends on the size? Avoiding a large global warrants
835 // plopping in more stores.
836 unsigned StoreBudget = 6;
837 uint64_t SizeLimit = 32;
839 return GlobalSize > SizeLimit &&
840 canEmitInitWithFewStoresAfterMemset(Init, StoreBudget);
843 /// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a
844 /// variable declaration with auto, register, or no storage class specifier.
845 /// These turn into simple stack objects, or GlobalValues depending on target.
846 void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
847 AutoVarEmission emission = EmitAutoVarAlloca(D);
848 EmitAutoVarInit(emission);
849 EmitAutoVarCleanups(emission);
852 /// Emit a lifetime.begin marker if some criteria are satisfied.
853 /// \return a pointer to the temporary size Value if a marker was emitted, null
855 llvm::Value *CodeGenFunction::EmitLifetimeStart(uint64_t Size,
857 // For now, only in optimized builds.
858 if (CGM.getCodeGenOpts().OptimizationLevel == 0)
861 // Disable lifetime markers in msan builds.
862 // FIXME: Remove this when msan works with lifetime markers.
863 if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
866 llvm::Value *SizeV = llvm::ConstantInt::get(Int64Ty, Size);
867 Addr = Builder.CreateBitCast(Addr, Int8PtrTy);
869 Builder.CreateCall(CGM.getLLVMLifetimeStartFn(), {SizeV, Addr});
870 C->setDoesNotThrow();
874 void CodeGenFunction::EmitLifetimeEnd(llvm::Value *Size, llvm::Value *Addr) {
875 Addr = Builder.CreateBitCast(Addr, Int8PtrTy);
877 Builder.CreateCall(CGM.getLLVMLifetimeEndFn(), {Size, Addr});
878 C->setDoesNotThrow();
881 /// EmitAutoVarAlloca - Emit the alloca and debug information for a
882 /// local variable. Does not emit initialization or destruction.
883 CodeGenFunction::AutoVarEmission
884 CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
885 QualType Ty = D.getType();
887 AutoVarEmission emission(D);
889 bool isByRef = D.hasAttr<BlocksAttr>();
890 emission.IsByRef = isByRef;
892 CharUnits alignment = getContext().getDeclAlign(&D);
893 emission.Alignment = alignment;
895 // If the type is variably-modified, emit all the VLA sizes for it.
896 if (Ty->isVariablyModifiedType())
897 EmitVariablyModifiedType(Ty);
899 llvm::Value *DeclPtr;
900 if (Ty->isConstantSizeType()) {
901 bool NRVO = getLangOpts().ElideConstructors &&
904 // If this value is an array or struct with a statically determinable
905 // constant initializer, there are optimizations we can do.
907 // TODO: We should constant-evaluate the initializer of any variable,
908 // as long as it is initialized by a constant expression. Currently,
909 // isConstantInitializer produces wrong answers for structs with
910 // reference or bitfield members, and a few other cases, and checking
911 // for POD-ness protects us from some of these.
912 if (D.getInit() && (Ty->isArrayType() || Ty->isRecordType()) &&
914 ((Ty.isPODType(getContext()) ||
915 getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) &&
916 D.getInit()->isConstantInitializer(getContext(), false)))) {
918 // If the variable's a const type, and it's neither an NRVO
919 // candidate nor a __block variable and has no mutable members,
920 // emit it as a global instead.
921 if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef &&
922 CGM.isTypeConstant(Ty, true)) {
923 EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
925 emission.Address = nullptr; // signal this condition to later callbacks
926 assert(emission.wasEmittedAsGlobal());
930 // Otherwise, tell the initialization code that we're in this case.
931 emission.IsConstantAggregate = true;
934 // A normal fixed sized variable becomes an alloca in the entry block,
935 // unless it's an NRVO variable.
936 llvm::Type *LTy = ConvertTypeForMem(Ty);
939 // The named return value optimization: allocate this variable in the
940 // return slot, so that we can elide the copy when returning this
941 // variable (C++0x [class.copy]p34).
942 DeclPtr = ReturnValue;
944 if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
945 if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) {
946 // Create a flag that is used to indicate when the NRVO was applied
947 // to this variable. Set it to zero to indicate that NRVO was not
949 llvm::Value *Zero = Builder.getFalse();
950 llvm::Value *NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo");
952 Builder.CreateStore(Zero, NRVOFlag);
954 // Record the NRVO flag for this variable.
955 NRVOFlags[&D] = NRVOFlag;
956 emission.NRVOFlag = NRVOFlag;
961 LTy = BuildByRefType(&D);
963 llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
964 Alloc->setName(D.getName());
966 CharUnits allocaAlignment = alignment;
968 allocaAlignment = std::max(allocaAlignment,
969 getContext().toCharUnitsFromBits(getTarget().getPointerAlign(0)));
970 Alloc->setAlignment(allocaAlignment.getQuantity());
973 // Emit a lifetime intrinsic if meaningful. There's no point
974 // in doing this if we don't have a valid insertion point (?).
975 uint64_t size = CGM.getDataLayout().getTypeAllocSize(LTy);
976 if (HaveInsertPoint()) {
977 emission.SizeForLifetimeMarkers = EmitLifetimeStart(size, Alloc);
979 assert(!emission.useLifetimeMarkers());
985 if (!DidCallStackSave) {
987 llvm::Value *Stack = CreateTempAlloca(Int8PtrTy, "saved_stack");
989 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
990 llvm::Value *V = Builder.CreateCall(F, {});
992 Builder.CreateStore(V, Stack);
994 DidCallStackSave = true;
996 // Push a cleanup block and restore the stack there.
997 // FIXME: in general circumstances, this should be an EH cleanup.
998 pushStackRestore(NormalCleanup, Stack);
1001 llvm::Value *elementCount;
1002 QualType elementType;
1003 std::tie(elementCount, elementType) = getVLASize(Ty);
1005 llvm::Type *llvmTy = ConvertTypeForMem(elementType);
1007 // Allocate memory for the array.
1008 llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla");
1009 vla->setAlignment(alignment.getQuantity());
1014 llvm::Value *&DMEntry = LocalDeclMap[&D];
1015 assert(!DMEntry && "Decl already exists in localdeclmap!");
1017 emission.Address = DeclPtr;
1019 // Emit debug info for local var declaration.
1020 if (HaveInsertPoint())
1021 if (CGDebugInfo *DI = getDebugInfo()) {
1022 if (CGM.getCodeGenOpts().getDebugInfo()
1023 >= CodeGenOptions::LimitedDebugInfo) {
1024 DI->setLocation(D.getLocation());
1025 DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
1029 if (D.hasAttr<AnnotateAttr>())
1030 EmitVarAnnotations(&D, emission.Address);
1035 /// Determines whether the given __block variable is potentially
1036 /// captured by the given expression.
1037 static bool isCapturedBy(const VarDecl &var, const Expr *e) {
1038 // Skip the most common kinds of expressions that make
1039 // hierarchy-walking expensive.
1040 e = e->IgnoreParenCasts();
1042 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
1043 const BlockDecl *block = be->getBlockDecl();
1044 for (const auto &I : block->captures()) {
1045 if (I.getVariable() == &var)
1049 // No need to walk into the subexpressions.
1053 if (const StmtExpr *SE = dyn_cast<StmtExpr>(e)) {
1054 const CompoundStmt *CS = SE->getSubStmt();
1055 for (const auto *BI : CS->body())
1056 if (const auto *E = dyn_cast<Expr>(BI)) {
1057 if (isCapturedBy(var, E))
1060 else if (const auto *DS = dyn_cast<DeclStmt>(BI)) {
1061 // special case declarations
1062 for (const auto *I : DS->decls()) {
1063 if (const auto *VD = dyn_cast<VarDecl>((I))) {
1064 const Expr *Init = VD->getInit();
1065 if (Init && isCapturedBy(var, Init))
1071 // FIXME. Make safe assumption assuming arbitrary statements cause capturing.
1072 // Later, provide code to poke into statements for capture analysis.
1077 for (const Stmt *SubStmt : e->children())
1078 if (isCapturedBy(var, cast<Expr>(SubStmt)))
1084 /// \brief Determine whether the given initializer is trivial in the sense
1085 /// that it requires no code to be generated.
1086 bool CodeGenFunction::isTrivialInitializer(const Expr *Init) {
1090 if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init))
1091 if (CXXConstructorDecl *Constructor = Construct->getConstructor())
1092 if (Constructor->isTrivial() &&
1093 Constructor->isDefaultConstructor() &&
1094 !Construct->requiresZeroInitialization())
1099 void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
1100 assert(emission.Variable && "emission was not valid!");
1102 // If this was emitted as a global constant, we're done.
1103 if (emission.wasEmittedAsGlobal()) return;
1105 const VarDecl &D = *emission.Variable;
1106 auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, D.getLocation());
1107 QualType type = D.getType();
1109 // If this local has an initializer, emit it now.
1110 const Expr *Init = D.getInit();
1112 // If we are at an unreachable point, we don't need to emit the initializer
1113 // unless it contains a label.
1114 if (!HaveInsertPoint()) {
1115 if (!Init || !ContainsLabel(Init)) return;
1116 EnsureInsertPoint();
1119 // Initialize the structure of a __block variable.
1120 if (emission.IsByRef)
1121 emitByrefStructureInit(emission);
1123 if (isTrivialInitializer(Init))
1126 CharUnits alignment = emission.Alignment;
1128 // Check whether this is a byref variable that's potentially
1129 // captured and moved by its own initializer. If so, we'll need to
1130 // emit the initializer first, then copy into the variable.
1131 bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init);
1134 capturedByInit ? emission.Address : emission.getObjectAddress(*this);
1136 llvm::Constant *constant = nullptr;
1137 if (emission.IsConstantAggregate || D.isConstexpr()) {
1138 assert(!capturedByInit && "constant init contains a capturing block?");
1139 constant = CGM.EmitConstantInit(D, this);
1143 LValue lv = MakeAddrLValue(Loc, type, alignment);
1145 return EmitExprAsInit(Init, &D, lv, capturedByInit);
1148 if (!emission.IsConstantAggregate) {
1149 // For simple scalar/complex initialization, store the value directly.
1150 LValue lv = MakeAddrLValue(Loc, type, alignment);
1152 return EmitStoreThroughLValue(RValue::get(constant), lv, true);
1155 // If this is a simple aggregate initialization, we can optimize it
1157 bool isVolatile = type.isVolatileQualified();
1159 llvm::Value *SizeVal =
1160 llvm::ConstantInt::get(IntPtrTy,
1161 getContext().getTypeSizeInChars(type).getQuantity());
1163 llvm::Type *BP = Int8PtrTy;
1164 if (Loc->getType() != BP)
1165 Loc = Builder.CreateBitCast(Loc, BP);
1167 // If the initializer is all or mostly zeros, codegen with memset then do
1168 // a few stores afterward.
1169 if (shouldUseMemSetPlusStoresToInitialize(constant,
1170 CGM.getDataLayout().getTypeAllocSize(constant->getType()))) {
1171 Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal,
1172 alignment.getQuantity(), isVolatile);
1173 // Zero and undef don't require a stores.
1174 if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) {
1175 Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo());
1176 emitStoresForInitAfterMemset(constant, Loc, isVolatile, Builder);
1179 // Otherwise, create a temporary global with the initializer then
1180 // memcpy from the global to the alloca.
1181 std::string Name = getStaticDeclName(CGM, D);
1182 llvm::GlobalVariable *GV =
1183 new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true,
1184 llvm::GlobalValue::PrivateLinkage,
1186 GV->setAlignment(alignment.getQuantity());
1187 GV->setUnnamedAddr(true);
1189 llvm::Value *SrcPtr = GV;
1190 if (SrcPtr->getType() != BP)
1191 SrcPtr = Builder.CreateBitCast(SrcPtr, BP);
1193 Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, alignment.getQuantity(),
1198 /// Emit an expression as an initializer for a variable at the given
1199 /// location. The expression is not necessarily the normal
1200 /// initializer for the variable, and the address is not necessarily
1201 /// its normal location.
1203 /// \param init the initializing expression
1204 /// \param var the variable to act as if we're initializing
1205 /// \param loc the address to initialize; its type is a pointer
1206 /// to the LLVM mapping of the variable's type
1207 /// \param alignment the alignment of the address
1208 /// \param capturedByInit true if the variable is a __block variable
1209 /// whose address is potentially changed by the initializer
1210 void CodeGenFunction::EmitExprAsInit(const Expr *init, const ValueDecl *D,
1211 LValue lvalue, bool capturedByInit) {
1212 QualType type = D->getType();
1214 if (type->isReferenceType()) {
1215 RValue rvalue = EmitReferenceBindingToExpr(init);
1217 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1218 EmitStoreThroughLValue(rvalue, lvalue, true);
1221 switch (getEvaluationKind(type)) {
1223 EmitScalarInit(init, D, lvalue, capturedByInit);
1226 ComplexPairTy complex = EmitComplexExpr(init);
1228 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1229 EmitStoreOfComplex(complex, lvalue, /*init*/ true);
1233 if (type->isAtomicType()) {
1234 EmitAtomicInit(const_cast<Expr*>(init), lvalue);
1236 // TODO: how can we delay here if D is captured by its initializer?
1237 EmitAggExpr(init, AggValueSlot::forLValue(lvalue,
1238 AggValueSlot::IsDestructed,
1239 AggValueSlot::DoesNotNeedGCBarriers,
1240 AggValueSlot::IsNotAliased));
1244 llvm_unreachable("bad evaluation kind");
1247 /// Enter a destroy cleanup for the given local variable.
1248 void CodeGenFunction::emitAutoVarTypeCleanup(
1249 const CodeGenFunction::AutoVarEmission &emission,
1250 QualType::DestructionKind dtorKind) {
1251 assert(dtorKind != QualType::DK_none);
1253 // Note that for __block variables, we want to destroy the
1254 // original stack object, not the possibly forwarded object.
1255 llvm::Value *addr = emission.getObjectAddress(*this);
1257 const VarDecl *var = emission.Variable;
1258 QualType type = var->getType();
1260 CleanupKind cleanupKind = NormalAndEHCleanup;
1261 CodeGenFunction::Destroyer *destroyer = nullptr;
1264 case QualType::DK_none:
1265 llvm_unreachable("no cleanup for trivially-destructible variable");
1267 case QualType::DK_cxx_destructor:
1268 // If there's an NRVO flag on the emission, we need a different
1270 if (emission.NRVOFlag) {
1271 assert(!type->isArrayType());
1272 CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor();
1273 EHStack.pushCleanup<DestroyNRVOVariable>(cleanupKind, addr, dtor,
1279 case QualType::DK_objc_strong_lifetime:
1280 // Suppress cleanups for pseudo-strong variables.
1281 if (var->isARCPseudoStrong()) return;
1283 // Otherwise, consider whether to use an EH cleanup or not.
1284 cleanupKind = getARCCleanupKind();
1286 // Use the imprecise destroyer by default.
1287 if (!var->hasAttr<ObjCPreciseLifetimeAttr>())
1288 destroyer = CodeGenFunction::destroyARCStrongImprecise;
1291 case QualType::DK_objc_weak_lifetime:
1295 // If we haven't chosen a more specific destroyer, use the default.
1296 if (!destroyer) destroyer = getDestroyer(dtorKind);
1298 // Use an EH cleanup in array destructors iff the destructor itself
1299 // is being pushed as an EH cleanup.
1300 bool useEHCleanup = (cleanupKind & EHCleanup);
1301 EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer,
1305 void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
1306 assert(emission.Variable && "emission was not valid!");
1308 // If this was emitted as a global constant, we're done.
1309 if (emission.wasEmittedAsGlobal()) return;
1311 // If we don't have an insertion point, we're done. Sema prevents
1312 // us from jumping into any of these scopes anyway.
1313 if (!HaveInsertPoint()) return;
1315 const VarDecl &D = *emission.Variable;
1317 // Make sure we call @llvm.lifetime.end. This needs to happen
1318 // *last*, so the cleanup needs to be pushed *first*.
1319 if (emission.useLifetimeMarkers()) {
1320 EHStack.pushCleanup<CallLifetimeEnd>(NormalCleanup,
1321 emission.getAllocatedAddress(),
1322 emission.getSizeForLifetimeMarkers());
1323 EHCleanupScope &cleanup = cast<EHCleanupScope>(*EHStack.begin());
1324 cleanup.setLifetimeMarker();
1327 // Check the type for a cleanup.
1328 if (QualType::DestructionKind dtorKind = D.getType().isDestructedType())
1329 emitAutoVarTypeCleanup(emission, dtorKind);
1331 // In GC mode, honor objc_precise_lifetime.
1332 if (getLangOpts().getGC() != LangOptions::NonGC &&
1333 D.hasAttr<ObjCPreciseLifetimeAttr>()) {
1334 EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D);
1337 // Handle the cleanup attribute.
1338 if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
1339 const FunctionDecl *FD = CA->getFunctionDecl();
1341 llvm::Constant *F = CGM.GetAddrOfFunction(FD);
1342 assert(F && "Could not find function!");
1344 const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD);
1345 EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D);
1348 // If this is a block variable, call _Block_object_destroy
1349 // (on the unforwarded address).
1350 if (emission.IsByRef)
1351 enterByrefCleanup(emission);
1354 CodeGenFunction::Destroyer *
1355 CodeGenFunction::getDestroyer(QualType::DestructionKind kind) {
1357 case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor");
1358 case QualType::DK_cxx_destructor:
1359 return destroyCXXObject;
1360 case QualType::DK_objc_strong_lifetime:
1361 return destroyARCStrongPrecise;
1362 case QualType::DK_objc_weak_lifetime:
1363 return destroyARCWeak;
1365 llvm_unreachable("Unknown DestructionKind");
1368 /// pushEHDestroy - Push the standard destructor for the given type as
1369 /// an EH-only cleanup.
1370 void CodeGenFunction::pushEHDestroy(QualType::DestructionKind dtorKind,
1371 llvm::Value *addr, QualType type) {
1372 assert(dtorKind && "cannot push destructor for trivial type");
1373 assert(needsEHCleanup(dtorKind));
1375 pushDestroy(EHCleanup, addr, type, getDestroyer(dtorKind), true);
1378 /// pushDestroy - Push the standard destructor for the given type as
1379 /// at least a normal cleanup.
1380 void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind,
1381 llvm::Value *addr, QualType type) {
1382 assert(dtorKind && "cannot push destructor for trivial type");
1384 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1385 pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind),
1386 cleanupKind & EHCleanup);
1389 void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, llvm::Value *addr,
1390 QualType type, Destroyer *destroyer,
1391 bool useEHCleanupForArray) {
1392 pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type,
1393 destroyer, useEHCleanupForArray);
1396 void CodeGenFunction::pushStackRestore(CleanupKind Kind, llvm::Value *SPMem) {
1397 EHStack.pushCleanup<CallStackRestore>(Kind, SPMem);
1400 void CodeGenFunction::pushLifetimeExtendedDestroy(
1401 CleanupKind cleanupKind, llvm::Value *addr, QualType type,
1402 Destroyer *destroyer, bool useEHCleanupForArray) {
1403 assert(!isInConditionalBranch() &&
1404 "performing lifetime extension from within conditional");
1406 // Push an EH-only cleanup for the object now.
1407 // FIXME: When popping normal cleanups, we need to keep this EH cleanup
1408 // around in case a temporary's destructor throws an exception.
1409 if (cleanupKind & EHCleanup)
1410 EHStack.pushCleanup<DestroyObject>(
1411 static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), addr, type,
1412 destroyer, useEHCleanupForArray);
1414 // Remember that we need to push a full cleanup for the object at the
1415 // end of the full-expression.
1416 pushCleanupAfterFullExpr<DestroyObject>(
1417 cleanupKind, addr, type, destroyer, useEHCleanupForArray);
1420 /// emitDestroy - Immediately perform the destruction of the given
1423 /// \param addr - the address of the object; a type*
1424 /// \param type - the type of the object; if an array type, all
1425 /// objects are destroyed in reverse order
1426 /// \param destroyer - the function to call to destroy individual
1428 /// \param useEHCleanupForArray - whether an EH cleanup should be
1429 /// used when destroying array elements, in case one of the
1430 /// destructions throws an exception
1431 void CodeGenFunction::emitDestroy(llvm::Value *addr, QualType type,
1432 Destroyer *destroyer,
1433 bool useEHCleanupForArray) {
1434 const ArrayType *arrayType = getContext().getAsArrayType(type);
1436 return destroyer(*this, addr, type);
1438 llvm::Value *begin = addr;
1439 llvm::Value *length = emitArrayLength(arrayType, type, begin);
1441 // Normally we have to check whether the array is zero-length.
1442 bool checkZeroLength = true;
1444 // But if the array length is constant, we can suppress that.
1445 if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) {
1446 // ...and if it's constant zero, we can just skip the entire thing.
1447 if (constLength->isZero()) return;
1448 checkZeroLength = false;
1451 llvm::Value *end = Builder.CreateInBoundsGEP(begin, length);
1452 emitArrayDestroy(begin, end, type, destroyer,
1453 checkZeroLength, useEHCleanupForArray);
1456 /// emitArrayDestroy - Destroys all the elements of the given array,
1457 /// beginning from last to first. The array cannot be zero-length.
1459 /// \param begin - a type* denoting the first element of the array
1460 /// \param end - a type* denoting one past the end of the array
1461 /// \param type - the element type of the array
1462 /// \param destroyer - the function to call to destroy elements
1463 /// \param useEHCleanup - whether to push an EH cleanup to destroy
1464 /// the remaining elements in case the destruction of a single
1466 void CodeGenFunction::emitArrayDestroy(llvm::Value *begin,
1469 Destroyer *destroyer,
1470 bool checkZeroLength,
1471 bool useEHCleanup) {
1472 assert(!type->isArrayType());
1474 // The basic structure here is a do-while loop, because we don't
1475 // need to check for the zero-element case.
1476 llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body");
1477 llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done");
1479 if (checkZeroLength) {
1480 llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end,
1481 "arraydestroy.isempty");
1482 Builder.CreateCondBr(isEmpty, doneBB, bodyBB);
1485 // Enter the loop body, making that address the current address.
1486 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1488 llvm::PHINode *elementPast =
1489 Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast");
1490 elementPast->addIncoming(end, entryBB);
1492 // Shift the address back by one element.
1493 llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true);
1494 llvm::Value *element = Builder.CreateInBoundsGEP(elementPast, negativeOne,
1495 "arraydestroy.element");
1498 pushRegularPartialArrayCleanup(begin, element, type, destroyer);
1500 // Perform the actual destruction there.
1501 destroyer(*this, element, type);
1506 // Check whether we've reached the end.
1507 llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done");
1508 Builder.CreateCondBr(done, doneBB, bodyBB);
1509 elementPast->addIncoming(element, Builder.GetInsertBlock());
1515 /// Perform partial array destruction as if in an EH cleanup. Unlike
1516 /// emitArrayDestroy, the element type here may still be an array type.
1517 static void emitPartialArrayDestroy(CodeGenFunction &CGF,
1518 llvm::Value *begin, llvm::Value *end,
1520 CodeGenFunction::Destroyer *destroyer) {
1521 // If the element type is itself an array, drill down.
1522 unsigned arrayDepth = 0;
1523 while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) {
1524 // VLAs don't require a GEP index to walk into.
1525 if (!isa<VariableArrayType>(arrayType))
1527 type = arrayType->getElementType();
1531 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, arrayDepth+1);
1533 SmallVector<llvm::Value*,4> gepIndices(arrayDepth, zero);
1534 begin = CGF.Builder.CreateInBoundsGEP(begin, gepIndices, "pad.arraybegin");
1535 end = CGF.Builder.CreateInBoundsGEP(end, gepIndices, "pad.arrayend");
1538 // Destroy the array. We don't ever need an EH cleanup because we
1539 // assume that we're in an EH cleanup ourselves, so a throwing
1540 // destructor causes an immediate terminate.
1541 CGF.emitArrayDestroy(begin, end, type, destroyer,
1542 /*checkZeroLength*/ true, /*useEHCleanup*/ false);
1546 /// RegularPartialArrayDestroy - a cleanup which performs a partial
1547 /// array destroy where the end pointer is regularly determined and
1548 /// does not need to be loaded from a local.
1549 class RegularPartialArrayDestroy : public EHScopeStack::Cleanup {
1550 llvm::Value *ArrayBegin;
1551 llvm::Value *ArrayEnd;
1552 QualType ElementType;
1553 CodeGenFunction::Destroyer *Destroyer;
1555 RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd,
1556 QualType elementType,
1557 CodeGenFunction::Destroyer *destroyer)
1558 : ArrayBegin(arrayBegin), ArrayEnd(arrayEnd),
1559 ElementType(elementType), Destroyer(destroyer) {}
1561 void Emit(CodeGenFunction &CGF, Flags flags) override {
1562 emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd,
1563 ElementType, Destroyer);
1567 /// IrregularPartialArrayDestroy - a cleanup which performs a
1568 /// partial array destroy where the end pointer is irregularly
1569 /// determined and must be loaded from a local.
1570 class IrregularPartialArrayDestroy : public EHScopeStack::Cleanup {
1571 llvm::Value *ArrayBegin;
1572 llvm::Value *ArrayEndPointer;
1573 QualType ElementType;
1574 CodeGenFunction::Destroyer *Destroyer;
1576 IrregularPartialArrayDestroy(llvm::Value *arrayBegin,
1577 llvm::Value *arrayEndPointer,
1578 QualType elementType,
1579 CodeGenFunction::Destroyer *destroyer)
1580 : ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer),
1581 ElementType(elementType), Destroyer(destroyer) {}
1583 void Emit(CodeGenFunction &CGF, Flags flags) override {
1584 llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer);
1585 emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd,
1586 ElementType, Destroyer);
1591 /// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy
1592 /// already-constructed elements of the given array. The cleanup
1593 /// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1595 /// \param elementType - the immediate element type of the array;
1596 /// possibly still an array type
1597 void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
1598 llvm::Value *arrayEndPointer,
1599 QualType elementType,
1600 Destroyer *destroyer) {
1601 pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup,
1602 arrayBegin, arrayEndPointer,
1603 elementType, destroyer);
1606 /// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
1607 /// already-constructed elements of the given array. The cleanup
1608 /// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1610 /// \param elementType - the immediate element type of the array;
1611 /// possibly still an array type
1612 void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin,
1613 llvm::Value *arrayEnd,
1614 QualType elementType,
1615 Destroyer *destroyer) {
1616 pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup,
1617 arrayBegin, arrayEnd,
1618 elementType, destroyer);
1621 /// Lazily declare the @llvm.lifetime.start intrinsic.
1622 llvm::Constant *CodeGenModule::getLLVMLifetimeStartFn() {
1623 if (LifetimeStartFn) return LifetimeStartFn;
1624 LifetimeStartFn = llvm::Intrinsic::getDeclaration(&getModule(),
1625 llvm::Intrinsic::lifetime_start);
1626 return LifetimeStartFn;
1629 /// Lazily declare the @llvm.lifetime.end intrinsic.
1630 llvm::Constant *CodeGenModule::getLLVMLifetimeEndFn() {
1631 if (LifetimeEndFn) return LifetimeEndFn;
1632 LifetimeEndFn = llvm::Intrinsic::getDeclaration(&getModule(),
1633 llvm::Intrinsic::lifetime_end);
1634 return LifetimeEndFn;
1638 /// A cleanup to perform a release of an object at the end of a
1639 /// function. This is used to balance out the incoming +1 of a
1640 /// ns_consumed argument when we can't reasonably do that just by
1641 /// not doing the initial retain for a __block argument.
1642 struct ConsumeARCParameter : EHScopeStack::Cleanup {
1643 ConsumeARCParameter(llvm::Value *param,
1644 ARCPreciseLifetime_t precise)
1645 : Param(param), Precise(precise) {}
1648 ARCPreciseLifetime_t Precise;
1650 void Emit(CodeGenFunction &CGF, Flags flags) override {
1651 CGF.EmitARCRelease(Param, Precise);
1656 /// Emit an alloca (or GlobalValue depending on target)
1657 /// for the specified parameter and set up LocalDeclMap.
1658 void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
1659 bool ArgIsPointer, unsigned ArgNo) {
1660 // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
1661 assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
1662 "Invalid argument to EmitParmDecl");
1664 Arg->setName(D.getName());
1666 QualType Ty = D.getType();
1668 // Use better IR generation for certain implicit parameters.
1669 if (isa<ImplicitParamDecl>(D)) {
1670 // The only implicit argument a block has is its literal.
1672 LocalDeclMap[&D] = Arg;
1673 llvm::Value *LocalAddr = nullptr;
1674 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1675 // Allocate a stack slot to let the debug info survive the RA.
1676 llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1677 D.getName() + ".addr");
1678 Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity());
1679 LValue lv = MakeAddrLValue(Alloc, Ty, getContext().getDeclAlign(&D));
1680 EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1681 LocalAddr = Builder.CreateLoad(Alloc);
1684 if (CGDebugInfo *DI = getDebugInfo()) {
1685 if (CGM.getCodeGenOpts().getDebugInfo()
1686 >= CodeGenOptions::LimitedDebugInfo) {
1687 DI->setLocation(D.getLocation());
1688 DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, Arg, ArgNo,
1689 LocalAddr, Builder);
1697 llvm::Value *DeclPtr;
1698 bool DoStore = false;
1699 bool IsScalar = hasScalarEvaluationKind(Ty);
1700 CharUnits Align = getContext().getDeclAlign(&D);
1701 // If we already have a pointer to the argument, reuse the input pointer.
1703 // If we have a prettier pointer type at this point, bitcast to that.
1704 unsigned AS = cast<llvm::PointerType>(Arg->getType())->getAddressSpace();
1705 llvm::Type *IRTy = ConvertTypeForMem(Ty)->getPointerTo(AS);
1706 DeclPtr = Arg->getType() == IRTy ? Arg : Builder.CreateBitCast(Arg, IRTy,
1708 // Push a destructor cleanup for this parameter if the ABI requires it.
1709 // Don't push a cleanup in a thunk for a method that will also emit a
1711 if (!IsScalar && !CurFuncIsThunk &&
1712 getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
1713 const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
1714 if (RD && RD->hasNonTrivialDestructor())
1715 pushDestroy(QualType::DK_cxx_destructor, DeclPtr, Ty);
1718 // Otherwise, create a temporary to hold the value.
1719 llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
1720 D.getName() + ".addr");
1721 Alloc->setAlignment(Align.getQuantity());
1726 LValue lv = MakeAddrLValue(DeclPtr, Ty, Align);
1728 Qualifiers qs = Ty.getQualifiers();
1729 if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) {
1730 // We honor __attribute__((ns_consumed)) for types with lifetime.
1731 // For __strong, it's handled by just skipping the initial retain;
1732 // otherwise we have to balance out the initial +1 with an extra
1733 // cleanup to do the release at the end of the function.
1734 bool isConsumed = D.hasAttr<NSConsumedAttr>();
1736 // 'self' is always formally __strong, but if this is not an
1737 // init method then we don't want to retain it.
1738 if (D.isARCPseudoStrong()) {
1739 const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CurCodeDecl);
1740 assert(&D == method->getSelfDecl());
1741 assert(lt == Qualifiers::OCL_Strong);
1742 assert(qs.hasConst());
1743 assert(method->getMethodFamily() != OMF_init);
1745 lt = Qualifiers::OCL_ExplicitNone;
1748 if (lt == Qualifiers::OCL_Strong) {
1750 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1751 // use objc_storeStrong(&dest, value) for retaining the
1752 // object. But first, store a null into 'dest' because
1753 // objc_storeStrong attempts to release its old value.
1754 llvm::Value *Null = CGM.EmitNullConstant(D.getType());
1755 EmitStoreOfScalar(Null, lv, /* isInitialization */ true);
1756 EmitARCStoreStrongCall(lv.getAddress(), Arg, true);
1760 // Don't use objc_retainBlock for block pointers, because we
1761 // don't want to Block_copy something just because we got it
1763 Arg = EmitARCRetainNonBlock(Arg);
1766 // Push the cleanup for a consumed parameter.
1768 ARCPreciseLifetime_t precise = (D.hasAttr<ObjCPreciseLifetimeAttr>()
1769 ? ARCPreciseLifetime : ARCImpreciseLifetime);
1770 EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), Arg,
1774 if (lt == Qualifiers::OCL_Weak) {
1775 EmitARCInitWeak(DeclPtr, Arg);
1776 DoStore = false; // The weak init is a store, no need to do two.
1780 // Enter the cleanup scope.
1781 EmitAutoVarWithLifetime(*this, D, DeclPtr, lt);
1785 // Store the initial value into the alloca.
1787 EmitStoreOfScalar(Arg, lv, /* isInitialization */ true);
1789 llvm::Value *&DMEntry = LocalDeclMap[&D];
1790 assert(!DMEntry && "Decl already exists in localdeclmap!");
1793 // Emit debug info for param declaration.
1794 if (CGDebugInfo *DI = getDebugInfo()) {
1795 if (CGM.getCodeGenOpts().getDebugInfo()
1796 >= CodeGenOptions::LimitedDebugInfo) {
1797 DI->EmitDeclareOfArgVariable(&D, DeclPtr, ArgNo, Builder);
1801 if (D.hasAttr<AnnotateAttr>())
1802 EmitVarAnnotations(&D, DeclPtr);