1 //===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This contains code dealing with code generation of C++ declarations
11 //===----------------------------------------------------------------------===//
13 #include "CodeGenFunction.h"
15 #include "CGObjCRuntime.h"
16 #include "CGOpenMPRuntime.h"
17 #include "TargetInfo.h"
18 #include "clang/Basic/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) {
30 (D.hasGlobalStorage() ||
31 (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) &&
32 "VarDecl must have global or local (in the case of OpenCL) storage!");
33 assert(!D.getType()->isReferenceType() &&
34 "Should not call EmitDeclInit on a reference!");
36 QualType type = D.getType();
37 LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
39 const Expr *Init = D.getInit();
40 switch (CGF.getEvaluationKind(type)) {
42 CodeGenModule &CGM = CGF.CGM;
43 if (lv.isObjCStrong())
44 CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
45 DeclPtr, D.getTLSKind());
46 else if (lv.isObjCWeak())
47 CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
50 CGF.EmitScalarInit(Init, &D, lv, false);
54 CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
57 CGF.EmitAggExpr(Init, AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
58 AggValueSlot::DoesNotNeedGCBarriers,
59 AggValueSlot::IsNotAliased,
60 AggValueSlot::DoesNotOverlap));
63 llvm_unreachable("bad evaluation kind");
66 /// Emit code to cause the destruction of the given variable with
67 /// static storage duration.
68 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
69 ConstantAddress Addr) {
70 // Honor __attribute__((no_destroy)) and bail instead of attempting
71 // to emit a reference to a possibly nonexistent destructor, which
72 // in turn can cause a crash. This will result in a global constructor
73 // that isn't balanced out by a destructor call as intended by the
74 // attribute. This also checks for -fno-c++-static-destructors and
75 // bails even if the attribute is not present.
76 QualType::DestructionKind DtorKind = D.needsDestruction(CGF.getContext());
78 // FIXME: __attribute__((cleanup)) ?
81 case QualType::DK_none:
84 case QualType::DK_cxx_destructor:
87 case QualType::DK_objc_strong_lifetime:
88 case QualType::DK_objc_weak_lifetime:
89 case QualType::DK_nontrivial_c_struct:
90 // We don't care about releasing objects during process teardown.
91 assert(!D.getTLSKind() && "should have rejected this");
95 llvm::FunctionCallee Func;
96 llvm::Constant *Argument;
98 CodeGenModule &CGM = CGF.CGM;
99 QualType Type = D.getType();
101 // Special-case non-array C++ destructors, if they have the right signature.
102 // Under some ABIs, destructors return this instead of void, and cannot be
103 // passed directly to __cxa_atexit if the target does not allow this
105 const CXXRecordDecl *Record = Type->getAsCXXRecordDecl();
106 bool CanRegisterDestructor =
107 Record && (!CGM.getCXXABI().HasThisReturn(
108 GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
109 CGM.getCXXABI().canCallMismatchedFunctionType());
110 // If __cxa_atexit is disabled via a flag, a different helper function is
111 // generated elsewhere which uses atexit instead, and it takes the destructor
113 bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
114 if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
115 assert(!Record->hasTrivialDestructor());
116 CXXDestructorDecl *Dtor = Record->getDestructor();
118 Func = CGM.getAddrAndTypeOfCXXStructor(GlobalDecl(Dtor, Dtor_Complete));
119 if (CGF.getContext().getLangOpts().OpenCL) {
121 CGM.getTargetCodeGenInfo().getAddrSpaceOfCxaAtexitPtrParam();
122 auto DestTy = CGF.getTypes().ConvertType(Type)->getPointerTo(
123 CGM.getContext().getTargetAddressSpace(DestAS));
124 auto SrcAS = D.getType().getQualifiers().getAddressSpace();
126 Argument = llvm::ConstantExpr::getBitCast(Addr.getPointer(), DestTy);
128 // FIXME: On addr space mismatch we are passing NULL. The generation
129 // of the global destructor function should be adjusted accordingly.
130 Argument = llvm::ConstantPointerNull::get(DestTy);
132 Argument = llvm::ConstantExpr::getBitCast(
133 Addr.getPointer(), CGF.getTypes().ConvertType(Type)->getPointerTo());
135 // Otherwise, the standard logic requires a helper function.
137 Func = CodeGenFunction(CGM)
138 .generateDestroyHelper(Addr, Type, CGF.getDestroyer(DtorKind),
139 CGF.needsEHCleanup(DtorKind), &D);
140 Argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
143 CGM.getCXXABI().registerGlobalDtor(CGF, D, Func, Argument);
146 /// Emit code to cause the variable at the given address to be considered as
147 /// constant from this point onwards.
148 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
149 llvm::Constant *Addr) {
150 return CGF.EmitInvariantStart(
151 Addr, CGF.getContext().getTypeSizeInChars(D.getType()));
154 void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
155 // Do not emit the intrinsic if we're not optimizing.
156 if (!CGM.getCodeGenOpts().OptimizationLevel)
159 // Grab the llvm.invariant.start intrinsic.
160 llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
161 // Overloaded address space type.
162 llvm::Type *ObjectPtr[1] = {Int8PtrTy};
163 llvm::Function *InvariantStart = CGM.getIntrinsic(InvStartID, ObjectPtr);
165 // Emit a call with the size in bytes of the object.
166 uint64_t Width = Size.getQuantity();
167 llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
168 llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
169 Builder.CreateCall(InvariantStart, Args);
172 void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
173 llvm::Constant *DeclPtr,
176 const Expr *Init = D.getInit();
177 QualType T = D.getType();
179 // The address space of a static local variable (DeclPtr) may be different
180 // from the address space of the "this" argument of the constructor. In that
181 // case, we need an addrspacecast before calling the constructor.
183 // struct StructWithCtor {
184 // __device__ StructWithCtor() {...}
186 // __device__ void foo() {
187 // __shared__ StructWithCtor s;
191 // For example, in the above CUDA code, the static local variable s has a
192 // "shared" address space qualifier, but the constructor of StructWithCtor
193 // expects "this" in the "generic" address space.
194 unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
195 unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
196 if (ActualAddrSpace != ExpectedAddrSpace) {
197 llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(T);
198 llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
199 DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
202 ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
204 if (!T->isReferenceType()) {
205 if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
206 D.hasAttr<OMPThreadPrivateDeclAttr>()) {
207 (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
208 &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
212 EmitDeclInit(*this, D, DeclAddr);
213 if (CGM.isTypeConstant(D.getType(), true))
214 EmitDeclInvariant(*this, D, DeclPtr);
216 EmitDeclDestroy(*this, D, DeclAddr);
220 assert(PerformInit && "cannot have constant initializer which needs "
221 "destruction for reference");
222 RValue RV = EmitReferenceBindingToExpr(Init);
223 EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
226 /// Create a stub function, suitable for being passed to atexit,
227 /// which passes the given address to the given destructor function.
228 llvm::Function *CodeGenFunction::createAtExitStub(const VarDecl &VD,
229 llvm::FunctionCallee dtor,
230 llvm::Constant *addr) {
231 // Get the destructor function type, void(*)(void).
232 llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
233 SmallString<256> FnName;
235 llvm::raw_svector_ostream Out(FnName);
236 CGM.getCXXABI().getMangleContext().mangleDynamicAtExitDestructor(&VD, Out);
239 const CGFunctionInfo &FI = CGM.getTypes().arrangeNullaryFunction();
240 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
241 ty, FnName.str(), FI, VD.getLocation());
243 CodeGenFunction CGF(CGM);
245 CGF.StartFunction(GlobalDecl(&VD, DynamicInitKind::AtExit),
246 CGM.getContext().VoidTy, fn, FI, FunctionArgList());
248 llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
250 // Make sure the call and the callee agree on calling convention.
251 if (auto *dtorFn = dyn_cast<llvm::Function>(
252 dtor.getCallee()->stripPointerCastsAndAliases()))
253 call->setCallingConv(dtorFn->getCallingConv());
255 CGF.FinishFunction();
260 /// Register a global destructor using the C atexit runtime function.
261 void CodeGenFunction::registerGlobalDtorWithAtExit(const VarDecl &VD,
262 llvm::FunctionCallee dtor,
263 llvm::Constant *addr) {
264 // Create a function which calls the destructor.
265 llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
266 registerGlobalDtorWithAtExit(dtorStub);
269 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
270 // extern "C" int atexit(void (*f)(void));
271 llvm::FunctionType *atexitTy =
272 llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
274 llvm::FunctionCallee atexit =
275 CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
277 if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit.getCallee()))
278 atexitFn->setDoesNotThrow();
280 EmitNounwindRuntimeCall(atexit, dtorStub);
283 void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
284 llvm::GlobalVariable *DeclPtr,
286 // If we've been asked to forbid guard variables, emit an error now.
287 // This diagnostic is hard-coded for Darwin's use case; we can find
288 // better phrasing if someone else needs it.
289 if (CGM.getCodeGenOpts().ForbidGuardVariables)
290 CGM.Error(D.getLocation(),
291 "this initialization requires a guard variable, which "
292 "the kernel does not support");
294 CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
297 void CodeGenFunction::EmitCXXGuardedInitBranch(llvm::Value *NeedsInit,
298 llvm::BasicBlock *InitBlock,
299 llvm::BasicBlock *NoInitBlock,
302 assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
304 // A guess at how many times we will enter the initialization of a
305 // variable, depending on the kind of variable.
306 static const uint64_t InitsPerTLSVar = 1024;
307 static const uint64_t InitsPerLocalVar = 1024 * 1024;
309 llvm::MDNode *Weights;
310 if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
311 // For non-local variables, don't apply any weighting for now. Due to our
312 // use of COMDATs, we expect there to be at most one initialization of the
313 // variable per DSO, but we have no way to know how many DSOs will try to
314 // initialize the variable.
318 // FIXME: For the TLS case, collect and use profiling information to
319 // determine a more accurate brach weight.
320 if (Kind == GuardKind::TlsGuard || D->getTLSKind())
321 NumInits = InitsPerTLSVar;
323 NumInits = InitsPerLocalVar;
325 // The probability of us entering the initializer is
326 // 1 / (total number of times we attempt to initialize the variable).
327 llvm::MDBuilder MDHelper(CGM.getLLVMContext());
328 Weights = MDHelper.createBranchWeights(1, NumInits - 1);
331 Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
334 llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
335 llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
336 SourceLocation Loc, bool TLS) {
338 llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
340 if (!getLangOpts().AppleKext && !TLS) {
341 // Set the section if needed.
342 if (const char *Section = getTarget().getStaticInitSectionSpecifier())
343 Fn->setSection(Section);
346 SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
348 Fn->setCallingConv(getRuntimeCC());
350 if (!getLangOpts().Exceptions)
351 Fn->setDoesNotThrow();
353 if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
354 !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
355 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
357 if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
358 !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
359 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
361 if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
362 !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
363 Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
365 if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
366 !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
367 Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
369 if (getLangOpts().Sanitize.has(SanitizerKind::MemTag) &&
370 !isInSanitizerBlacklist(SanitizerKind::MemTag, Fn, Loc))
371 Fn->addFnAttr(llvm::Attribute::SanitizeMemTag);
373 if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
374 !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
375 Fn->addFnAttr(llvm::Attribute::SanitizeThread);
377 if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
378 !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
379 Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
381 if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
382 !isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
383 Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
385 if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
386 !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
387 Fn->addFnAttr(llvm::Attribute::SafeStack);
389 if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
390 !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
391 Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
393 auto RASignKind = getCodeGenOpts().getSignReturnAddress();
394 if (RASignKind != CodeGenOptions::SignReturnAddressScope::None) {
395 Fn->addFnAttr("sign-return-address",
396 RASignKind == CodeGenOptions::SignReturnAddressScope::All
399 auto RASignKey = getCodeGenOpts().getSignReturnAddressKey();
400 Fn->addFnAttr("sign-return-address-key",
401 RASignKey == CodeGenOptions::SignReturnAddressKeyValue::AKey
406 if (getCodeGenOpts().BranchTargetEnforcement)
407 Fn->addFnAttr("branch-target-enforcement");
412 /// Create a global pointer to a function that will initialize a global
413 /// variable. The user has requested that this pointer be emitted in a specific
415 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
416 llvm::GlobalVariable *GV,
417 llvm::Function *InitFunc,
419 llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
420 TheModule, InitFunc->getType(), /*isConstant=*/true,
421 llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
422 PtrArray->setSection(ISA->getSection());
423 addUsedGlobal(PtrArray);
425 // If the GV is already in a comdat group, then we have to join it.
426 if (llvm::Comdat *C = GV->getComdat())
427 PtrArray->setComdat(C);
431 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
432 llvm::GlobalVariable *Addr,
435 // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
436 // __constant__ and __shared__ variables defined in namespace scope,
437 // that are of class type, cannot have a non-empty constructor. All
438 // the checks have been done in Sema by now. Whatever initializers
439 // are allowed are empty and we just need to ignore them here.
440 if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
441 (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
442 D->hasAttr<CUDASharedAttr>()))
445 if (getLangOpts().OpenMP &&
446 getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
449 // Check if we've already initialized this decl.
450 auto I = DelayedCXXInitPosition.find(D);
451 if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
454 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
455 SmallString<256> FnName;
457 llvm::raw_svector_ostream Out(FnName);
458 getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
461 // Create a variable initialization function.
463 CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
464 getTypes().arrangeNullaryFunction(),
467 auto *ISA = D->getAttr<InitSegAttr>();
468 CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
471 llvm::GlobalVariable *COMDATKey =
472 supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
474 if (D->getTLSKind()) {
475 // FIXME: Should we support init_priority for thread_local?
476 // FIXME: We only need to register one __cxa_thread_atexit function for the
478 CXXThreadLocalInits.push_back(Fn);
479 CXXThreadLocalInitVars.push_back(D);
480 } else if (PerformInit && ISA) {
481 EmitPointerToInitFunc(D, Addr, Fn, ISA);
482 } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
483 OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
484 PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
485 } else if (isTemplateInstantiation(D->getTemplateSpecializationKind()) ||
486 getContext().GetGVALinkageForVariable(D) == GVA_DiscardableODR) {
487 // C++ [basic.start.init]p2:
488 // Definitions of explicitly specialized class template static data
489 // members have ordered initialization. Other class template static data
490 // members (i.e., implicitly or explicitly instantiated specializations)
491 // have unordered initialization.
493 // As a consequence, we can put them into their own llvm.global_ctors entry.
495 // If the global is externally visible, put the initializer into a COMDAT
496 // group with the global being initialized. On most platforms, this is a
497 // minor startup time optimization. In the MS C++ ABI, there are no guard
498 // variables, so this COMDAT key is required for correctness.
499 AddGlobalCtor(Fn, 65535, COMDATKey);
500 if (getTarget().getCXXABI().isMicrosoft() && COMDATKey) {
501 // In The MS C++, MS add template static data member in the linker
503 addUsedGlobal(COMDATKey);
505 } else if (D->hasAttr<SelectAnyAttr>()) {
506 // SelectAny globals will be comdat-folded. Put the initializer into a
507 // COMDAT group associated with the global, so the initializers get folded
509 AddGlobalCtor(Fn, 65535, COMDATKey);
511 I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
512 if (I == DelayedCXXInitPosition.end()) {
513 CXXGlobalInits.push_back(Fn);
514 } else if (I->second != ~0U) {
515 assert(I->second < CXXGlobalInits.size() &&
516 CXXGlobalInits[I->second] == nullptr);
517 CXXGlobalInits[I->second] = Fn;
521 // Remember that we already emitted the initializer for this global.
522 DelayedCXXInitPosition[D] = ~0U;
525 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
526 getCXXABI().EmitThreadLocalInitFuncs(
527 *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
529 CXXThreadLocalInits.clear();
530 CXXThreadLocalInitVars.clear();
531 CXXThreadLocals.clear();
535 CodeGenModule::EmitCXXGlobalInitFunc() {
536 while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
537 CXXGlobalInits.pop_back();
539 if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
542 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
543 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
545 // Create our global initialization function.
546 if (!PrioritizedCXXGlobalInits.empty()) {
547 SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
548 llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
549 PrioritizedCXXGlobalInits.end());
550 // Iterate over "chunks" of ctors with same priority and emit each chunk
551 // into separate function. Note - everything is sorted first by priority,
552 // second - by lex order, so we emit ctor functions in proper order.
553 for (SmallVectorImpl<GlobalInitData >::iterator
554 I = PrioritizedCXXGlobalInits.begin(),
555 E = PrioritizedCXXGlobalInits.end(); I != E; ) {
556 SmallVectorImpl<GlobalInitData >::iterator
557 PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
559 LocalCXXGlobalInits.clear();
560 unsigned Priority = I->first.priority;
561 // Compute the function suffix from priority. Prepend with zeroes to make
562 // sure the function names are also ordered as priorities.
563 std::string PrioritySuffix = llvm::utostr(Priority);
564 // Priority is always <= 65535 (enforced by sema).
565 PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
566 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
567 FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
569 for (; I < PrioE; ++I)
570 LocalCXXGlobalInits.push_back(I->second);
572 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
573 AddGlobalCtor(Fn, Priority);
575 PrioritizedCXXGlobalInits.clear();
578 // Include the filename in the symbol name. Including "sub_" matches gcc and
579 // makes sure these symbols appear lexicographically behind the symbols with
580 // priority emitted above.
581 SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
582 if (FileName.empty())
585 for (size_t i = 0; i < FileName.size(); ++i) {
586 // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
587 // to be the set of C preprocessing numbers.
588 if (!isPreprocessingNumberBody(FileName[i]))
592 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
593 FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
595 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
598 // In OpenCL global init functions must be converted to kernels in order to
599 // be able to launch them from the host.
600 // FIXME: Some more work might be needed to handle destructors correctly.
601 // Current initialization function makes use of function pointers callbacks.
602 // We can't support function pointers especially between host and device.
603 // However it seems global destruction has little meaning without any
604 // dynamic resource allocation on the device and program scope variables are
605 // destroyed by the runtime when program is released.
606 if (getLangOpts().OpenCL) {
607 GenOpenCLArgMetadata(Fn);
608 Fn->setCallingConv(llvm::CallingConv::SPIR_KERNEL);
611 CXXGlobalInits.clear();
614 void CodeGenModule::EmitCXXGlobalDtorFunc() {
615 if (CXXGlobalDtors.empty())
618 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
620 // Create our global destructor function.
621 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
623 CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
625 CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
629 /// Emit the code necessary to initialize the given global variable.
630 void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
632 llvm::GlobalVariable *Addr,
634 // Check if we need to emit debug info for variable initializer.
635 if (D->hasAttr<NoDebugAttr>())
636 DebugInfo = nullptr; // disable debug info indefinitely for this function
638 CurEHLocation = D->getBeginLoc();
640 StartFunction(GlobalDecl(D, DynamicInitKind::Initializer),
641 getContext().VoidTy, Fn, getTypes().arrangeNullaryFunction(),
642 FunctionArgList(), D->getLocation(),
643 D->getInit()->getExprLoc());
645 // Use guarded initialization if the global variable is weak. This
646 // occurs for, e.g., instantiated static data members and
647 // definitions explicitly marked weak.
649 // Also use guarded initialization for a variable with dynamic TLS and
650 // unordered initialization. (If the initialization is ordered, the ABI
651 // layer will guard the whole-TU initialization for us.)
652 if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage() ||
653 (D->getTLSKind() == VarDecl::TLS_Dynamic &&
654 isTemplateInstantiation(D->getTemplateSpecializationKind()))) {
655 EmitCXXGuardedInit(*D, Addr, PerformInit);
657 EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
664 CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
665 ArrayRef<llvm::Function *> Decls,
666 ConstantAddress Guard) {
668 auto NL = ApplyDebugLocation::CreateEmpty(*this);
669 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
670 getTypes().arrangeNullaryFunction(), FunctionArgList());
671 // Emit an artificial location for this function.
672 auto AL = ApplyDebugLocation::CreateArtificial(*this);
674 llvm::BasicBlock *ExitBlock = nullptr;
675 if (Guard.isValid()) {
676 // If we have a guard variable, check whether we've already performed
677 // these initializations. This happens for TLS initialization functions.
678 llvm::Value *GuardVal = Builder.CreateLoad(Guard);
679 llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
680 "guard.uninitialized");
681 llvm::BasicBlock *InitBlock = createBasicBlock("init");
682 ExitBlock = createBasicBlock("exit");
683 EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
684 GuardKind::TlsGuard, nullptr);
685 EmitBlock(InitBlock);
686 // Mark as initialized before initializing anything else. If the
687 // initializers use previously-initialized thread_local vars, that's
688 // probably supposed to be OK, but the standard doesn't say.
689 Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
691 // The guard variable can't ever change again.
694 CharUnits::fromQuantity(
695 CGM.getDataLayout().getTypeAllocSize(GuardVal->getType())));
698 RunCleanupsScope Scope(*this);
700 // When building in Objective-C++ ARC mode, create an autorelease pool
701 // around the global initializers.
702 if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
703 llvm::Value *token = EmitObjCAutoreleasePoolPush();
704 EmitObjCAutoreleasePoolCleanup(token);
707 for (unsigned i = 0, e = Decls.size(); i != e; ++i)
709 EmitRuntimeCall(Decls[i]);
711 Scope.ForceCleanup();
714 Builder.CreateBr(ExitBlock);
715 EmitBlock(ExitBlock);
722 void CodeGenFunction::GenerateCXXGlobalDtorsFunc(
724 const std::vector<std::tuple<llvm::FunctionType *, llvm::WeakTrackingVH,
725 llvm::Constant *>> &DtorsAndObjects) {
727 auto NL = ApplyDebugLocation::CreateEmpty(*this);
728 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
729 getTypes().arrangeNullaryFunction(), FunctionArgList());
730 // Emit an artificial location for this function.
731 auto AL = ApplyDebugLocation::CreateArtificial(*this);
733 // Emit the dtors, in reverse order from construction.
734 for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
735 llvm::FunctionType *CalleeTy;
738 std::tie(CalleeTy, Callee, Arg) = DtorsAndObjects[e - i - 1];
739 llvm::CallInst *CI = Builder.CreateCall(CalleeTy, Callee, Arg);
740 // Make sure the call and the callee agree on calling convention.
741 if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
742 CI->setCallingConv(F->getCallingConv());
749 /// generateDestroyHelper - Generates a helper function which, when
750 /// invoked, destroys the given object. The address of the object
751 /// should be in global memory.
752 llvm::Function *CodeGenFunction::generateDestroyHelper(
753 Address addr, QualType type, Destroyer *destroyer,
754 bool useEHCleanupForArray, const VarDecl *VD) {
755 FunctionArgList args;
756 ImplicitParamDecl Dst(getContext(), getContext().VoidPtrTy,
757 ImplicitParamDecl::Other);
758 args.push_back(&Dst);
760 const CGFunctionInfo &FI =
761 CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, args);
762 llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
763 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
764 FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
766 CurEHLocation = VD->getBeginLoc();
768 StartFunction(VD, getContext().VoidTy, fn, FI, args);
770 emitDestroy(addr, type, destroyer, useEHCleanupForArray);