1 //===--- CGDeclCXX.cpp - Emit LLVM Code for C++ 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 dealing with code generation of C++ declarations
12 //===----------------------------------------------------------------------===//
14 #include "CodeGenFunction.h"
16 #include "CGObjCRuntime.h"
17 #include "CGOpenMPRuntime.h"
18 #include "clang/Frontend/CodeGenOptions.h"
19 #include "llvm/ADT/StringExtras.h"
20 #include "llvm/IR/Intrinsics.h"
21 #include "llvm/IR/MDBuilder.h"
22 #include "llvm/Support/Path.h"
24 using namespace clang;
25 using namespace CodeGen;
27 static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
28 ConstantAddress DeclPtr) {
29 assert(D.hasGlobalStorage() && "VarDecl must have global storage!");
30 assert(!D.getType()->isReferenceType() &&
31 "Should not call EmitDeclInit on a reference!");
33 QualType type = D.getType();
34 LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
36 const Expr *Init = D.getInit();
37 switch (CGF.getEvaluationKind(type)) {
39 CodeGenModule &CGM = CGF.CGM;
40 if (lv.isObjCStrong())
41 CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
42 DeclPtr, D.getTLSKind());
43 else if (lv.isObjCWeak())
44 CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
47 CGF.EmitScalarInit(Init, &D, lv, false);
51 CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
54 CGF.EmitAggExpr(Init, AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
55 AggValueSlot::DoesNotNeedGCBarriers,
56 AggValueSlot::IsNotAliased,
57 AggValueSlot::DoesNotOverlap));
60 llvm_unreachable("bad evaluation kind");
63 /// Emit code to cause the destruction of the given variable with
64 /// static storage duration.
65 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
66 ConstantAddress addr) {
67 CodeGenModule &CGM = CGF.CGM;
69 // FIXME: __attribute__((cleanup)) ?
71 QualType type = D.getType();
72 QualType::DestructionKind dtorKind = type.isDestructedType();
75 case QualType::DK_none:
78 case QualType::DK_cxx_destructor:
81 case QualType::DK_objc_strong_lifetime:
82 case QualType::DK_objc_weak_lifetime:
83 case QualType::DK_nontrivial_c_struct:
84 // We don't care about releasing objects during process teardown.
85 assert(!D.getTLSKind() && "should have rejected this");
89 llvm::Constant *function;
90 llvm::Constant *argument;
92 // Special-case non-array C++ destructors, if they have the right signature.
93 // Under some ABIs, destructors return this instead of void, and cannot be
94 // passed directly to __cxa_atexit if the target does not allow this mismatch.
95 const CXXRecordDecl *Record = type->getAsCXXRecordDecl();
96 bool CanRegisterDestructor =
97 Record && (!CGM.getCXXABI().HasThisReturn(
98 GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
99 CGM.getCXXABI().canCallMismatchedFunctionType());
100 // If __cxa_atexit is disabled via a flag, a different helper function is
101 // generated elsewhere which uses atexit instead, and it takes the destructor
103 bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
104 if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
105 assert(!Record->hasTrivialDestructor());
106 CXXDestructorDecl *dtor = Record->getDestructor();
108 function = CGM.getAddrOfCXXStructor(dtor, StructorType::Complete);
109 argument = llvm::ConstantExpr::getBitCast(
110 addr.getPointer(), CGF.getTypes().ConvertType(type)->getPointerTo());
112 // Otherwise, the standard logic requires a helper function.
114 function = CodeGenFunction(CGM)
115 .generateDestroyHelper(addr, type, CGF.getDestroyer(dtorKind),
116 CGF.needsEHCleanup(dtorKind), &D);
117 argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
120 CGM.getCXXABI().registerGlobalDtor(CGF, D, function, argument);
123 /// Emit code to cause the variable at the given address to be considered as
124 /// constant from this point onwards.
125 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
126 llvm::Constant *Addr) {
127 // Do not emit the intrinsic if we're not optimizing.
128 if (!CGF.CGM.getCodeGenOpts().OptimizationLevel)
131 // Grab the llvm.invariant.start intrinsic.
132 llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
133 // Overloaded address space type.
134 llvm::Type *ObjectPtr[1] = {CGF.Int8PtrTy};
135 llvm::Constant *InvariantStart = CGF.CGM.getIntrinsic(InvStartID, ObjectPtr);
137 // Emit a call with the size in bytes of the object.
138 CharUnits WidthChars = CGF.getContext().getTypeSizeInChars(D.getType());
139 uint64_t Width = WidthChars.getQuantity();
140 llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, Width),
141 llvm::ConstantExpr::getBitCast(Addr, CGF.Int8PtrTy)};
142 CGF.Builder.CreateCall(InvariantStart, Args);
145 void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
146 llvm::Constant *DeclPtr,
149 const Expr *Init = D.getInit();
150 QualType T = D.getType();
152 // The address space of a static local variable (DeclPtr) may be different
153 // from the address space of the "this" argument of the constructor. In that
154 // case, we need an addrspacecast before calling the constructor.
156 // struct StructWithCtor {
157 // __device__ StructWithCtor() {...}
159 // __device__ void foo() {
160 // __shared__ StructWithCtor s;
164 // For example, in the above CUDA code, the static local variable s has a
165 // "shared" address space qualifier, but the constructor of StructWithCtor
166 // expects "this" in the "generic" address space.
167 unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
168 unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
169 if (ActualAddrSpace != ExpectedAddrSpace) {
170 llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(T);
171 llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
172 DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
175 ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
177 if (!T->isReferenceType()) {
178 if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
179 D.hasAttr<OMPThreadPrivateDeclAttr>()) {
180 (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
181 &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
185 EmitDeclInit(*this, D, DeclAddr);
186 if (CGM.isTypeConstant(D.getType(), true))
187 EmitDeclInvariant(*this, D, DeclPtr);
189 EmitDeclDestroy(*this, D, DeclAddr);
193 assert(PerformInit && "cannot have constant initializer which needs "
194 "destruction for reference");
195 RValue RV = EmitReferenceBindingToExpr(Init);
196 EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
199 /// Create a stub function, suitable for being passed to atexit,
200 /// which passes the given address to the given destructor function.
201 llvm::Constant *CodeGenFunction::createAtExitStub(const VarDecl &VD,
202 llvm::Constant *dtor,
203 llvm::Constant *addr) {
204 // Get the destructor function type, void(*)(void).
205 llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
206 SmallString<256> FnName;
208 llvm::raw_svector_ostream Out(FnName);
209 CGM.getCXXABI().getMangleContext().mangleDynamicAtExitDestructor(&VD, Out);
212 const CGFunctionInfo &FI = CGM.getTypes().arrangeNullaryFunction();
213 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
217 CodeGenFunction CGF(CGM);
219 CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn, FI, FunctionArgList());
221 llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
223 // Make sure the call and the callee agree on calling convention.
224 if (llvm::Function *dtorFn =
225 dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
226 call->setCallingConv(dtorFn->getCallingConv());
228 CGF.FinishFunction();
233 /// Register a global destructor using the C atexit runtime function.
234 void CodeGenFunction::registerGlobalDtorWithAtExit(const VarDecl &VD,
235 llvm::Constant *dtor,
236 llvm::Constant *addr) {
237 // Create a function which calls the destructor.
238 llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
239 registerGlobalDtorWithAtExit(dtorStub);
242 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
243 // extern "C" int atexit(void (*f)(void));
244 llvm::FunctionType *atexitTy =
245 llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
247 llvm::Constant *atexit =
248 CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
250 if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
251 atexitFn->setDoesNotThrow();
253 EmitNounwindRuntimeCall(atexit, dtorStub);
256 void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
257 llvm::GlobalVariable *DeclPtr,
259 // If we've been asked to forbid guard variables, emit an error now.
260 // This diagnostic is hard-coded for Darwin's use case; we can find
261 // better phrasing if someone else needs it.
262 if (CGM.getCodeGenOpts().ForbidGuardVariables)
263 CGM.Error(D.getLocation(),
264 "this initialization requires a guard variable, which "
265 "the kernel does not support");
267 CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
270 void CodeGenFunction::EmitCXXGuardedInitBranch(llvm::Value *NeedsInit,
271 llvm::BasicBlock *InitBlock,
272 llvm::BasicBlock *NoInitBlock,
275 assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
277 // A guess at how many times we will enter the initialization of a
278 // variable, depending on the kind of variable.
279 static const uint64_t InitsPerTLSVar = 1024;
280 static const uint64_t InitsPerLocalVar = 1024 * 1024;
282 llvm::MDNode *Weights;
283 if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
284 // For non-local variables, don't apply any weighting for now. Due to our
285 // use of COMDATs, we expect there to be at most one initialization of the
286 // variable per DSO, but we have no way to know how many DSOs will try to
287 // initialize the variable.
291 // FIXME: For the TLS case, collect and use profiling information to
292 // determine a more accurate brach weight.
293 if (Kind == GuardKind::TlsGuard || D->getTLSKind())
294 NumInits = InitsPerTLSVar;
296 NumInits = InitsPerLocalVar;
298 // The probability of us entering the initializer is
299 // 1 / (total number of times we attempt to initialize the variable).
300 llvm::MDBuilder MDHelper(CGM.getLLVMContext());
301 Weights = MDHelper.createBranchWeights(1, NumInits - 1);
304 Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
307 llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
308 llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
309 SourceLocation Loc, bool TLS) {
311 llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
313 if (!getLangOpts().AppleKext && !TLS) {
314 // Set the section if needed.
315 if (const char *Section = getTarget().getStaticInitSectionSpecifier())
316 Fn->setSection(Section);
319 SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
321 Fn->setCallingConv(getRuntimeCC());
323 if (!getLangOpts().Exceptions)
324 Fn->setDoesNotThrow();
326 if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
327 !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
328 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
330 if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
331 !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
332 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
334 if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
335 !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
336 Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
338 if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
339 !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
340 Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
342 if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
343 !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
344 Fn->addFnAttr(llvm::Attribute::SanitizeThread);
346 if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
347 !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
348 Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
350 if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
351 !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
352 Fn->addFnAttr(llvm::Attribute::SafeStack);
354 if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
355 !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
356 Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
361 /// Create a global pointer to a function that will initialize a global
362 /// variable. The user has requested that this pointer be emitted in a specific
364 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
365 llvm::GlobalVariable *GV,
366 llvm::Function *InitFunc,
368 llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
369 TheModule, InitFunc->getType(), /*isConstant=*/true,
370 llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
371 PtrArray->setSection(ISA->getSection());
372 addUsedGlobal(PtrArray);
374 // If the GV is already in a comdat group, then we have to join it.
375 if (llvm::Comdat *C = GV->getComdat())
376 PtrArray->setComdat(C);
380 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
381 llvm::GlobalVariable *Addr,
384 // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
385 // __constant__ and __shared__ variables defined in namespace scope,
386 // that are of class type, cannot have a non-empty constructor. All
387 // the checks have been done in Sema by now. Whatever initializers
388 // are allowed are empty and we just need to ignore them here.
389 if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
390 (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
391 D->hasAttr<CUDASharedAttr>()))
394 if (getLangOpts().OpenMP &&
395 getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
398 // Check if we've already initialized this decl.
399 auto I = DelayedCXXInitPosition.find(D);
400 if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
403 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
404 SmallString<256> FnName;
406 llvm::raw_svector_ostream Out(FnName);
407 getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
410 // Create a variable initialization function.
412 CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
413 getTypes().arrangeNullaryFunction(),
416 auto *ISA = D->getAttr<InitSegAttr>();
417 CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
420 llvm::GlobalVariable *COMDATKey =
421 supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
423 if (D->getTLSKind()) {
424 // FIXME: Should we support init_priority for thread_local?
425 // FIXME: We only need to register one __cxa_thread_atexit function for the
427 CXXThreadLocalInits.push_back(Fn);
428 CXXThreadLocalInitVars.push_back(D);
429 } else if (PerformInit && ISA) {
430 EmitPointerToInitFunc(D, Addr, Fn, ISA);
431 } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
432 OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
433 PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
434 } else if (isTemplateInstantiation(D->getTemplateSpecializationKind())) {
435 // C++ [basic.start.init]p2:
436 // Definitions of explicitly specialized class template static data
437 // members have ordered initialization. Other class template static data
438 // members (i.e., implicitly or explicitly instantiated specializations)
439 // have unordered initialization.
441 // As a consequence, we can put them into their own llvm.global_ctors entry.
443 // If the global is externally visible, put the initializer into a COMDAT
444 // group with the global being initialized. On most platforms, this is a
445 // minor startup time optimization. In the MS C++ ABI, there are no guard
446 // variables, so this COMDAT key is required for correctness.
447 AddGlobalCtor(Fn, 65535, COMDATKey);
448 } else if (D->hasAttr<SelectAnyAttr>()) {
449 // SelectAny globals will be comdat-folded. Put the initializer into a
450 // COMDAT group associated with the global, so the initializers get folded
452 AddGlobalCtor(Fn, 65535, COMDATKey);
454 I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
455 if (I == DelayedCXXInitPosition.end()) {
456 CXXGlobalInits.push_back(Fn);
457 } else if (I->second != ~0U) {
458 assert(I->second < CXXGlobalInits.size() &&
459 CXXGlobalInits[I->second] == nullptr);
460 CXXGlobalInits[I->second] = Fn;
464 // Remember that we already emitted the initializer for this global.
465 DelayedCXXInitPosition[D] = ~0U;
468 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
469 getCXXABI().EmitThreadLocalInitFuncs(
470 *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
472 CXXThreadLocalInits.clear();
473 CXXThreadLocalInitVars.clear();
474 CXXThreadLocals.clear();
478 CodeGenModule::EmitCXXGlobalInitFunc() {
479 while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
480 CXXGlobalInits.pop_back();
482 if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
485 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
486 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
488 // Create our global initialization function.
489 if (!PrioritizedCXXGlobalInits.empty()) {
490 SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
491 llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
492 PrioritizedCXXGlobalInits.end());
493 // Iterate over "chunks" of ctors with same priority and emit each chunk
494 // into separate function. Note - everything is sorted first by priority,
495 // second - by lex order, so we emit ctor functions in proper order.
496 for (SmallVectorImpl<GlobalInitData >::iterator
497 I = PrioritizedCXXGlobalInits.begin(),
498 E = PrioritizedCXXGlobalInits.end(); I != E; ) {
499 SmallVectorImpl<GlobalInitData >::iterator
500 PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
502 LocalCXXGlobalInits.clear();
503 unsigned Priority = I->first.priority;
504 // Compute the function suffix from priority. Prepend with zeroes to make
505 // sure the function names are also ordered as priorities.
506 std::string PrioritySuffix = llvm::utostr(Priority);
507 // Priority is always <= 65535 (enforced by sema).
508 PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
509 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
510 FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
512 for (; I < PrioE; ++I)
513 LocalCXXGlobalInits.push_back(I->second);
515 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
516 AddGlobalCtor(Fn, Priority);
518 PrioritizedCXXGlobalInits.clear();
521 // Include the filename in the symbol name. Including "sub_" matches gcc and
522 // makes sure these symbols appear lexicographically behind the symbols with
523 // priority emitted above.
524 SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
525 if (FileName.empty())
528 for (size_t i = 0; i < FileName.size(); ++i) {
529 // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
530 // to be the set of C preprocessing numbers.
531 if (!isPreprocessingNumberBody(FileName[i]))
535 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
536 FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
538 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
541 CXXGlobalInits.clear();
544 void CodeGenModule::EmitCXXGlobalDtorFunc() {
545 if (CXXGlobalDtors.empty())
548 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
550 // Create our global destructor function.
551 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
553 CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
555 CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
559 /// Emit the code necessary to initialize the given global variable.
560 void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
562 llvm::GlobalVariable *Addr,
564 // Check if we need to emit debug info for variable initializer.
565 if (D->hasAttr<NoDebugAttr>())
566 DebugInfo = nullptr; // disable debug info indefinitely for this function
568 CurEHLocation = D->getLocStart();
570 StartFunction(GlobalDecl(D), getContext().VoidTy, Fn,
571 getTypes().arrangeNullaryFunction(),
572 FunctionArgList(), D->getLocation(),
573 D->getInit()->getExprLoc());
575 // Use guarded initialization if the global variable is weak. This
576 // occurs for, e.g., instantiated static data members and
577 // definitions explicitly marked weak.
578 if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
579 EmitCXXGuardedInit(*D, Addr, PerformInit);
581 EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
588 CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
589 ArrayRef<llvm::Function *> Decls,
592 auto NL = ApplyDebugLocation::CreateEmpty(*this);
593 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
594 getTypes().arrangeNullaryFunction(), FunctionArgList());
595 // Emit an artificial location for this function.
596 auto AL = ApplyDebugLocation::CreateArtificial(*this);
598 llvm::BasicBlock *ExitBlock = nullptr;
599 if (Guard.isValid()) {
600 // If we have a guard variable, check whether we've already performed
601 // these initializations. This happens for TLS initialization functions.
602 llvm::Value *GuardVal = Builder.CreateLoad(Guard);
603 llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
604 "guard.uninitialized");
605 llvm::BasicBlock *InitBlock = createBasicBlock("init");
606 ExitBlock = createBasicBlock("exit");
607 EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
608 GuardKind::TlsGuard, nullptr);
609 EmitBlock(InitBlock);
610 // Mark as initialized before initializing anything else. If the
611 // initializers use previously-initialized thread_local vars, that's
612 // probably supposed to be OK, but the standard doesn't say.
613 Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
616 RunCleanupsScope Scope(*this);
618 // When building in Objective-C++ ARC mode, create an autorelease pool
619 // around the global initializers.
620 if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
621 llvm::Value *token = EmitObjCAutoreleasePoolPush();
622 EmitObjCAutoreleasePoolCleanup(token);
625 for (unsigned i = 0, e = Decls.size(); i != e; ++i)
627 EmitRuntimeCall(Decls[i]);
629 Scope.ForceCleanup();
632 Builder.CreateBr(ExitBlock);
633 EmitBlock(ExitBlock);
640 void CodeGenFunction::GenerateCXXGlobalDtorsFunc(
642 const std::vector<std::pair<llvm::WeakTrackingVH, llvm::Constant *>>
645 auto NL = ApplyDebugLocation::CreateEmpty(*this);
646 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
647 getTypes().arrangeNullaryFunction(), FunctionArgList());
648 // Emit an artificial location for this function.
649 auto AL = ApplyDebugLocation::CreateArtificial(*this);
651 // Emit the dtors, in reverse order from construction.
652 for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
653 llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
654 llvm::CallInst *CI = Builder.CreateCall(Callee,
655 DtorsAndObjects[e - i - 1].second);
656 // Make sure the call and the callee agree on calling convention.
657 if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
658 CI->setCallingConv(F->getCallingConv());
665 /// generateDestroyHelper - Generates a helper function which, when
666 /// invoked, destroys the given object. The address of the object
667 /// should be in global memory.
668 llvm::Function *CodeGenFunction::generateDestroyHelper(
669 Address addr, QualType type, Destroyer *destroyer,
670 bool useEHCleanupForArray, const VarDecl *VD) {
671 FunctionArgList args;
672 ImplicitParamDecl Dst(getContext(), getContext().VoidPtrTy,
673 ImplicitParamDecl::Other);
674 args.push_back(&Dst);
676 const CGFunctionInfo &FI =
677 CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, args);
678 llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
679 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
680 FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
682 CurEHLocation = VD->getLocStart();
684 StartFunction(VD, getContext().VoidTy, fn, FI, args);
686 emitDestroy(addr, type, destroyer, useEHCleanupForArray);