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comparison clang/lib/CodeGen/CGDeclCXX.cpp @ 150:1d019706d866

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LLVM10
author anatofuz
date Thu, 13 Feb 2020 15:10:13 +0900
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147:c2174574ed3a 150:1d019706d866
1 //===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
2 //
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
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code dealing with code generation of C++ declarations
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "CGCXXABI.h"
14 #include "CGObjCRuntime.h"
15 #include "CGOpenMPRuntime.h"
16 #include "CodeGenFunction.h"
17 #include "TargetInfo.h"
18 #include "clang/AST/Attr.h"
19 #include "clang/Basic/CodeGenOptions.h"
20 #include "llvm/ADT/StringExtras.h"
21 #include "llvm/IR/Intrinsics.h"
22 #include "llvm/IR/MDBuilder.h"
23 #include "llvm/Support/Path.h"
24
25 using namespace clang;
26 using namespace CodeGen;
27
28 static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
29 ConstantAddress DeclPtr) {
30 assert(
31 (D.hasGlobalStorage() ||
32 (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) &&
33 "VarDecl must have global or local (in the case of OpenCL) storage!");
34 assert(!D.getType()->isReferenceType() &&
35 "Should not call EmitDeclInit on a reference!");
36
37 QualType type = D.getType();
38 LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
39
40 const Expr *Init = D.getInit();
41 switch (CGF.getEvaluationKind(type)) {
42 case TEK_Scalar: {
43 CodeGenModule &CGM = CGF.CGM;
44 if (lv.isObjCStrong())
45 CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
46 DeclPtr, D.getTLSKind());
47 else if (lv.isObjCWeak())
48 CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
49 DeclPtr);
50 else
51 CGF.EmitScalarInit(Init, &D, lv, false);
52 return;
53 }
54 case TEK_Complex:
55 CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
56 return;
57 case TEK_Aggregate:
58 CGF.EmitAggExpr(Init,
59 AggValueSlot::forLValue(lv, CGF, AggValueSlot::IsDestructed,
60 AggValueSlot::DoesNotNeedGCBarriers,
61 AggValueSlot::IsNotAliased,
62 AggValueSlot::DoesNotOverlap));
63 return;
64 }
65 llvm_unreachable("bad evaluation kind");
66 }
67
68 /// Emit code to cause the destruction of the given variable with
69 /// static storage duration.
70 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
71 ConstantAddress Addr) {
72 // Honor __attribute__((no_destroy)) and bail instead of attempting
73 // to emit a reference to a possibly nonexistent destructor, which
74 // in turn can cause a crash. This will result in a global constructor
75 // that isn't balanced out by a destructor call as intended by the
76 // attribute. This also checks for -fno-c++-static-destructors and
77 // bails even if the attribute is not present.
78 QualType::DestructionKind DtorKind = D.needsDestruction(CGF.getContext());
79
80 // FIXME: __attribute__((cleanup)) ?
81
82 switch (DtorKind) {
83 case QualType::DK_none:
84 return;
85
86 case QualType::DK_cxx_destructor:
87 break;
88
89 case QualType::DK_objc_strong_lifetime:
90 case QualType::DK_objc_weak_lifetime:
91 case QualType::DK_nontrivial_c_struct:
92 // We don't care about releasing objects during process teardown.
93 assert(!D.getTLSKind() && "should have rejected this");
94 return;
95 }
96
97 llvm::FunctionCallee Func;
98 llvm::Constant *Argument;
99
100 CodeGenModule &CGM = CGF.CGM;
101 QualType Type = D.getType();
102
103 // Special-case non-array C++ destructors, if they have the right signature.
104 // Under some ABIs, destructors return this instead of void, and cannot be
105 // passed directly to __cxa_atexit if the target does not allow this
106 // mismatch.
107 const CXXRecordDecl *Record = Type->getAsCXXRecordDecl();
108 bool CanRegisterDestructor =
109 Record && (!CGM.getCXXABI().HasThisReturn(
110 GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
111 CGM.getCXXABI().canCallMismatchedFunctionType());
112 // If __cxa_atexit is disabled via a flag, a different helper function is
113 // generated elsewhere which uses atexit instead, and it takes the destructor
114 // directly.
115 bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
116 if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
117 assert(!Record->hasTrivialDestructor());
118 CXXDestructorDecl *Dtor = Record->getDestructor();
119
120 Func = CGM.getAddrAndTypeOfCXXStructor(GlobalDecl(Dtor, Dtor_Complete));
121 if (CGF.getContext().getLangOpts().OpenCL) {
122 auto DestAS =
123 CGM.getTargetCodeGenInfo().getAddrSpaceOfCxaAtexitPtrParam();
124 auto DestTy = CGF.getTypes().ConvertType(Type)->getPointerTo(
125 CGM.getContext().getTargetAddressSpace(DestAS));
126 auto SrcAS = D.getType().getQualifiers().getAddressSpace();
127 if (DestAS == SrcAS)
128 Argument = llvm::ConstantExpr::getBitCast(Addr.getPointer(), DestTy);
129 else
130 // FIXME: On addr space mismatch we are passing NULL. The generation
131 // of the global destructor function should be adjusted accordingly.
132 Argument = llvm::ConstantPointerNull::get(DestTy);
133 } else {
134 Argument = llvm::ConstantExpr::getBitCast(
135 Addr.getPointer(), CGF.getTypes().ConvertType(Type)->getPointerTo());
136 }
137 // Otherwise, the standard logic requires a helper function.
138 } else {
139 Func = CodeGenFunction(CGM)
140 .generateDestroyHelper(Addr, Type, CGF.getDestroyer(DtorKind),
141 CGF.needsEHCleanup(DtorKind), &D);
142 Argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
143 }
144
145 CGM.getCXXABI().registerGlobalDtor(CGF, D, Func, Argument);
146 }
147
148 /// Emit code to cause the variable at the given address to be considered as
149 /// constant from this point onwards.
150 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
151 llvm::Constant *Addr) {
152 return CGF.EmitInvariantStart(
153 Addr, CGF.getContext().getTypeSizeInChars(D.getType()));
154 }
155
156 void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
157 // Do not emit the intrinsic if we're not optimizing.
158 if (!CGM.getCodeGenOpts().OptimizationLevel)
159 return;
160
161 // Grab the llvm.invariant.start intrinsic.
162 llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
163 // Overloaded address space type.
164 llvm::Type *ObjectPtr[1] = {Int8PtrTy};
165 llvm::Function *InvariantStart = CGM.getIntrinsic(InvStartID, ObjectPtr);
166
167 // Emit a call with the size in bytes of the object.
168 uint64_t Width = Size.getQuantity();
169 llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
170 llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
171 Builder.CreateCall(InvariantStart, Args);
172 }
173
174 void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
175 llvm::Constant *DeclPtr,
176 bool PerformInit) {
177
178 const Expr *Init = D.getInit();
179 QualType T = D.getType();
180
181 // The address space of a static local variable (DeclPtr) may be different
182 // from the address space of the "this" argument of the constructor. In that
183 // case, we need an addrspacecast before calling the constructor.
184 //
185 // struct StructWithCtor {
186 // __device__ StructWithCtor() {...}
187 // };
188 // __device__ void foo() {
189 // __shared__ StructWithCtor s;
190 // ...
191 // }
192 //
193 // For example, in the above CUDA code, the static local variable s has a
194 // "shared" address space qualifier, but the constructor of StructWithCtor
195 // expects "this" in the "generic" address space.
196 unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
197 unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
198 if (ActualAddrSpace != ExpectedAddrSpace) {
199 llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(T);
200 llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
201 DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
202 }
203
204 ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
205
206 if (!T->isReferenceType()) {
207 if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
208 D.hasAttr<OMPThreadPrivateDeclAttr>()) {
209 (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
210 &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
211 PerformInit, this);
212 }
213 if (PerformInit)
214 EmitDeclInit(*this, D, DeclAddr);
215 if (CGM.isTypeConstant(D.getType(), true))
216 EmitDeclInvariant(*this, D, DeclPtr);
217 else
218 EmitDeclDestroy(*this, D, DeclAddr);
219 return;
220 }
221
222 assert(PerformInit && "cannot have constant initializer which needs "
223 "destruction for reference");
224 RValue RV = EmitReferenceBindingToExpr(Init);
225 EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
226 }
227
228 /// Create a stub function, suitable for being passed to atexit,
229 /// which passes the given address to the given destructor function.
230 llvm::Function *CodeGenFunction::createAtExitStub(const VarDecl &VD,
231 llvm::FunctionCallee dtor,
232 llvm::Constant *addr) {
233 // Get the destructor function type, void(*)(void).
234 llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
235 SmallString<256> FnName;
236 {
237 llvm::raw_svector_ostream Out(FnName);
238 CGM.getCXXABI().getMangleContext().mangleDynamicAtExitDestructor(&VD, Out);
239 }
240
241 const CGFunctionInfo &FI = CGM.getTypes().arrangeNullaryFunction();
242 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
243 ty, FnName.str(), FI, VD.getLocation());
244
245 CodeGenFunction CGF(CGM);
246
247 CGF.StartFunction(GlobalDecl(&VD, DynamicInitKind::AtExit),
248 CGM.getContext().VoidTy, fn, FI, FunctionArgList());
249
250 llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
251
252 // Make sure the call and the callee agree on calling convention.
253 if (auto *dtorFn = dyn_cast<llvm::Function>(
254 dtor.getCallee()->stripPointerCastsAndAliases()))
255 call->setCallingConv(dtorFn->getCallingConv());
256
257 CGF.FinishFunction();
258
259 return fn;
260 }
261
262 /// Register a global destructor using the C atexit runtime function.
263 void CodeGenFunction::registerGlobalDtorWithAtExit(const VarDecl &VD,
264 llvm::FunctionCallee dtor,
265 llvm::Constant *addr) {
266 // Create a function which calls the destructor.
267 llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
268 registerGlobalDtorWithAtExit(dtorStub);
269 }
270
271 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
272 // extern "C" int atexit(void (*f)(void));
273 llvm::FunctionType *atexitTy =
274 llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
275
276 llvm::FunctionCallee atexit =
277 CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
278 /*Local=*/true);
279 if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit.getCallee()))
280 atexitFn->setDoesNotThrow();
281
282 EmitNounwindRuntimeCall(atexit, dtorStub);
283 }
284
285 void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
286 llvm::GlobalVariable *DeclPtr,
287 bool PerformInit) {
288 // If we've been asked to forbid guard variables, emit an error now.
289 // This diagnostic is hard-coded for Darwin's use case; we can find
290 // better phrasing if someone else needs it.
291 if (CGM.getCodeGenOpts().ForbidGuardVariables)
292 CGM.Error(D.getLocation(),
293 "this initialization requires a guard variable, which "
294 "the kernel does not support");
295
296 CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
297 }
298
299 void CodeGenFunction::EmitCXXGuardedInitBranch(llvm::Value *NeedsInit,
300 llvm::BasicBlock *InitBlock,
301 llvm::BasicBlock *NoInitBlock,
302 GuardKind Kind,
303 const VarDecl *D) {
304 assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
305
306 // A guess at how many times we will enter the initialization of a
307 // variable, depending on the kind of variable.
308 static const uint64_t InitsPerTLSVar = 1024;
309 static const uint64_t InitsPerLocalVar = 1024 * 1024;
310
311 llvm::MDNode *Weights;
312 if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
313 // For non-local variables, don't apply any weighting for now. Due to our
314 // use of COMDATs, we expect there to be at most one initialization of the
315 // variable per DSO, but we have no way to know how many DSOs will try to
316 // initialize the variable.
317 Weights = nullptr;
318 } else {
319 uint64_t NumInits;
320 // FIXME: For the TLS case, collect and use profiling information to
321 // determine a more accurate brach weight.
322 if (Kind == GuardKind::TlsGuard || D->getTLSKind())
323 NumInits = InitsPerTLSVar;
324 else
325 NumInits = InitsPerLocalVar;
326
327 // The probability of us entering the initializer is
328 // 1 / (total number of times we attempt to initialize the variable).
329 llvm::MDBuilder MDHelper(CGM.getLLVMContext());
330 Weights = MDHelper.createBranchWeights(1, NumInits - 1);
331 }
332
333 Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
334 }
335
336 llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
337 llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
338 SourceLocation Loc, bool TLS) {
339 llvm::Function *Fn =
340 llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
341 Name, &getModule());
342 if (!getLangOpts().AppleKext && !TLS) {
343 // Set the section if needed.
344 if (const char *Section = getTarget().getStaticInitSectionSpecifier())
345 Fn->setSection(Section);
346 }
347
348 SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
349
350 Fn->setCallingConv(getRuntimeCC());
351
352 if (!getLangOpts().Exceptions)
353 Fn->setDoesNotThrow();
354
355 if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
356 !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
357 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
358
359 if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
360 !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
361 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
362
363 if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
364 !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
365 Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
366
367 if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
368 !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
369 Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
370
371 if (getLangOpts().Sanitize.has(SanitizerKind::MemTag) &&
372 !isInSanitizerBlacklist(SanitizerKind::MemTag, Fn, Loc))
373 Fn->addFnAttr(llvm::Attribute::SanitizeMemTag);
374
375 if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
376 !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
377 Fn->addFnAttr(llvm::Attribute::SanitizeThread);
378
379 if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
380 !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
381 Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
382
383 if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
384 !isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
385 Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
386
387 if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
388 !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
389 Fn->addFnAttr(llvm::Attribute::SafeStack);
390
391 if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
392 !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
393 Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
394
395 auto RASignKind = getCodeGenOpts().getSignReturnAddress();
396 if (RASignKind != CodeGenOptions::SignReturnAddressScope::None) {
397 Fn->addFnAttr("sign-return-address",
398 RASignKind == CodeGenOptions::SignReturnAddressScope::All
399 ? "all"
400 : "non-leaf");
401 auto RASignKey = getCodeGenOpts().getSignReturnAddressKey();
402 Fn->addFnAttr("sign-return-address-key",
403 RASignKey == CodeGenOptions::SignReturnAddressKeyValue::AKey
404 ? "a_key"
405 : "b_key");
406 }
407
408 if (getCodeGenOpts().BranchTargetEnforcement)
409 Fn->addFnAttr("branch-target-enforcement");
410
411 return Fn;
412 }
413
414 /// Create a global pointer to a function that will initialize a global
415 /// variable. The user has requested that this pointer be emitted in a specific
416 /// section.
417 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
418 llvm::GlobalVariable *GV,
419 llvm::Function *InitFunc,
420 InitSegAttr *ISA) {
421 llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
422 TheModule, InitFunc->getType(), /*isConstant=*/true,
423 llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
424 PtrArray->setSection(ISA->getSection());
425 addUsedGlobal(PtrArray);
426
427 // If the GV is already in a comdat group, then we have to join it.
428 if (llvm::Comdat *C = GV->getComdat())
429 PtrArray->setComdat(C);
430 }
431
432 void
433 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
434 llvm::GlobalVariable *Addr,
435 bool PerformInit) {
436
437 // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
438 // __constant__ and __shared__ variables defined in namespace scope,
439 // that are of class type, cannot have a non-empty constructor. All
440 // the checks have been done in Sema by now. Whatever initializers
441 // are allowed are empty and we just need to ignore them here.
442 if (getLangOpts().CUDAIsDevice && !getLangOpts().GPUAllowDeviceInit &&
443 (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
444 D->hasAttr<CUDASharedAttr>()))
445 return;
446
447 if (getLangOpts().OpenMP &&
448 getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
449 return;
450
451 // Check if we've already initialized this decl.
452 auto I = DelayedCXXInitPosition.find(D);
453 if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
454 return;
455
456 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
457 SmallString<256> FnName;
458 {
459 llvm::raw_svector_ostream Out(FnName);
460 getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
461 }
462
463 // Create a variable initialization function.
464 llvm::Function *Fn =
465 CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
466 getTypes().arrangeNullaryFunction(),
467 D->getLocation());
468
469 auto *ISA = D->getAttr<InitSegAttr>();
470 CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
471 PerformInit);
472
473 llvm::GlobalVariable *COMDATKey =
474 supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
475
476 if (D->getTLSKind()) {
477 // FIXME: Should we support init_priority for thread_local?
478 // FIXME: We only need to register one __cxa_thread_atexit function for the
479 // entire TU.
480 CXXThreadLocalInits.push_back(Fn);
481 CXXThreadLocalInitVars.push_back(D);
482 } else if (PerformInit && ISA) {
483 EmitPointerToInitFunc(D, Addr, Fn, ISA);
484 } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
485 OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
486 PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
487 } else if (isTemplateInstantiation(D->getTemplateSpecializationKind()) ||
488 getContext().GetGVALinkageForVariable(D) == GVA_DiscardableODR) {
489 // C++ [basic.start.init]p2:
490 // Definitions of explicitly specialized class template static data
491 // members have ordered initialization. Other class template static data
492 // members (i.e., implicitly or explicitly instantiated specializations)
493 // have unordered initialization.
494 //
495 // As a consequence, we can put them into their own llvm.global_ctors entry.
496 //
497 // If the global is externally visible, put the initializer into a COMDAT
498 // group with the global being initialized. On most platforms, this is a
499 // minor startup time optimization. In the MS C++ ABI, there are no guard
500 // variables, so this COMDAT key is required for correctness.
501 AddGlobalCtor(Fn, 65535, COMDATKey);
502 if (getTarget().getCXXABI().isMicrosoft() && COMDATKey) {
503 // In The MS C++, MS add template static data member in the linker
504 // drective.
505 addUsedGlobal(COMDATKey);
506 }
507 } else if (D->hasAttr<SelectAnyAttr>()) {
508 // SelectAny globals will be comdat-folded. Put the initializer into a
509 // COMDAT group associated with the global, so the initializers get folded
510 // too.
511 AddGlobalCtor(Fn, 65535, COMDATKey);
512 } else {
513 I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
514 if (I == DelayedCXXInitPosition.end()) {
515 CXXGlobalInits.push_back(Fn);
516 } else if (I->second != ~0U) {
517 assert(I->second < CXXGlobalInits.size() &&
518 CXXGlobalInits[I->second] == nullptr);
519 CXXGlobalInits[I->second] = Fn;
520 }
521 }
522
523 // Remember that we already emitted the initializer for this global.
524 DelayedCXXInitPosition[D] = ~0U;
525 }
526
527 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
528 getCXXABI().EmitThreadLocalInitFuncs(
529 *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
530
531 CXXThreadLocalInits.clear();
532 CXXThreadLocalInitVars.clear();
533 CXXThreadLocals.clear();
534 }
535
536 void
537 CodeGenModule::EmitCXXGlobalInitFunc() {
538 while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
539 CXXGlobalInits.pop_back();
540
541 if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
542 return;
543
544 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
545 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
546
547 // Create our global initialization function.
548 if (!PrioritizedCXXGlobalInits.empty()) {
549 SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
550 llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
551 PrioritizedCXXGlobalInits.end());
552 // Iterate over "chunks" of ctors with same priority and emit each chunk
553 // into separate function. Note - everything is sorted first by priority,
554 // second - by lex order, so we emit ctor functions in proper order.
555 for (SmallVectorImpl<GlobalInitData >::iterator
556 I = PrioritizedCXXGlobalInits.begin(),
557 E = PrioritizedCXXGlobalInits.end(); I != E; ) {
558 SmallVectorImpl<GlobalInitData >::iterator
559 PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
560
561 LocalCXXGlobalInits.clear();
562 unsigned Priority = I->first.priority;
563 // Compute the function suffix from priority. Prepend with zeroes to make
564 // sure the function names are also ordered as priorities.
565 std::string PrioritySuffix = llvm::utostr(Priority);
566 // Priority is always <= 65535 (enforced by sema).
567 PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
568 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
569 FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
570
571 for (; I < PrioE; ++I)
572 LocalCXXGlobalInits.push_back(I->second);
573
574 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
575 AddGlobalCtor(Fn, Priority);
576 }
577 PrioritizedCXXGlobalInits.clear();
578 }
579
580 // Include the filename in the symbol name. Including "sub_" matches gcc and
581 // makes sure these symbols appear lexicographically behind the symbols with
582 // priority emitted above.
583 SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
584 if (FileName.empty())
585 FileName = "<null>";
586
587 for (size_t i = 0; i < FileName.size(); ++i) {
588 // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
589 // to be the set of C preprocessing numbers.
590 if (!isPreprocessingNumberBody(FileName[i]))
591 FileName[i] = '_';
592 }
593
594 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
595 FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
596
597 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
598 AddGlobalCtor(Fn);
599
600 // In OpenCL global init functions must be converted to kernels in order to
601 // be able to launch them from the host.
602 // FIXME: Some more work might be needed to handle destructors correctly.
603 // Current initialization function makes use of function pointers callbacks.
604 // We can't support function pointers especially between host and device.
605 // However it seems global destruction has little meaning without any
606 // dynamic resource allocation on the device and program scope variables are
607 // destroyed by the runtime when program is released.
608 if (getLangOpts().OpenCL) {
609 GenOpenCLArgMetadata(Fn);
610 Fn->setCallingConv(llvm::CallingConv::SPIR_KERNEL);
611 }
612
613 if (getLangOpts().HIP) {
614 Fn->setCallingConv(llvm::CallingConv::AMDGPU_KERNEL);
615 Fn->addFnAttr("device-init");
616 }
617
618 CXXGlobalInits.clear();
619 }
620
621 void CodeGenModule::EmitCXXGlobalDtorFunc() {
622 if (CXXGlobalDtors.empty())
623 return;
624
625 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
626
627 // Create our global destructor function.
628 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
629 llvm::Function *Fn =
630 CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
631
632 CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
633 AddGlobalDtor(Fn);
634 }
635
636 /// Emit the code necessary to initialize the given global variable.
637 void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
638 const VarDecl *D,
639 llvm::GlobalVariable *Addr,
640 bool PerformInit) {
641 // Check if we need to emit debug info for variable initializer.
642 if (D->hasAttr<NoDebugAttr>())
643 DebugInfo = nullptr; // disable debug info indefinitely for this function
644
645 CurEHLocation = D->getBeginLoc();
646
647 StartFunction(GlobalDecl(D, DynamicInitKind::Initializer),
648 getContext().VoidTy, Fn, getTypes().arrangeNullaryFunction(),
649 FunctionArgList(), D->getLocation(),
650 D->getInit()->getExprLoc());
651
652 // Use guarded initialization if the global variable is weak. This
653 // occurs for, e.g., instantiated static data members and
654 // definitions explicitly marked weak.
655 //
656 // Also use guarded initialization for a variable with dynamic TLS and
657 // unordered initialization. (If the initialization is ordered, the ABI
658 // layer will guard the whole-TU initialization for us.)
659 if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage() ||
660 (D->getTLSKind() == VarDecl::TLS_Dynamic &&
661 isTemplateInstantiation(D->getTemplateSpecializationKind()))) {
662 EmitCXXGuardedInit(*D, Addr, PerformInit);
663 } else {
664 EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
665 }
666
667 FinishFunction();
668 }
669
670 void
671 CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
672 ArrayRef<llvm::Function *> Decls,
673 ConstantAddress Guard) {
674 {
675 auto NL = ApplyDebugLocation::CreateEmpty(*this);
676 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
677 getTypes().arrangeNullaryFunction(), FunctionArgList());
678 // Emit an artificial location for this function.
679 auto AL = ApplyDebugLocation::CreateArtificial(*this);
680
681 llvm::BasicBlock *ExitBlock = nullptr;
682 if (Guard.isValid()) {
683 // If we have a guard variable, check whether we've already performed
684 // these initializations. This happens for TLS initialization functions.
685 llvm::Value *GuardVal = Builder.CreateLoad(Guard);
686 llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
687 "guard.uninitialized");
688 llvm::BasicBlock *InitBlock = createBasicBlock("init");
689 ExitBlock = createBasicBlock("exit");
690 EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
691 GuardKind::TlsGuard, nullptr);
692 EmitBlock(InitBlock);
693 // Mark as initialized before initializing anything else. If the
694 // initializers use previously-initialized thread_local vars, that's
695 // probably supposed to be OK, but the standard doesn't say.
696 Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
697
698 // The guard variable can't ever change again.
699 EmitInvariantStart(
700 Guard.getPointer(),
701 CharUnits::fromQuantity(
702 CGM.getDataLayout().getTypeAllocSize(GuardVal->getType())));
703 }
704
705 RunCleanupsScope Scope(*this);
706
707 // When building in Objective-C++ ARC mode, create an autorelease pool
708 // around the global initializers.
709 if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
710 llvm::Value *token = EmitObjCAutoreleasePoolPush();
711 EmitObjCAutoreleasePoolCleanup(token);
712 }
713
714 for (unsigned i = 0, e = Decls.size(); i != e; ++i)
715 if (Decls[i])
716 EmitRuntimeCall(Decls[i]);
717
718 Scope.ForceCleanup();
719
720 if (ExitBlock) {
721 Builder.CreateBr(ExitBlock);
722 EmitBlock(ExitBlock);
723 }
724 }
725
726 FinishFunction();
727 }
728
729 void CodeGenFunction::GenerateCXXGlobalDtorsFunc(
730 llvm::Function *Fn,
731 const std::vector<std::tuple<llvm::FunctionType *, llvm::WeakTrackingVH,
732 llvm::Constant *>> &DtorsAndObjects) {
733 {
734 auto NL = ApplyDebugLocation::CreateEmpty(*this);
735 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
736 getTypes().arrangeNullaryFunction(), FunctionArgList());
737 // Emit an artificial location for this function.
738 auto AL = ApplyDebugLocation::CreateArtificial(*this);
739
740 // Emit the dtors, in reverse order from construction.
741 for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
742 llvm::FunctionType *CalleeTy;
743 llvm::Value *Callee;
744 llvm::Constant *Arg;
745 std::tie(CalleeTy, Callee, Arg) = DtorsAndObjects[e - i - 1];
746 llvm::CallInst *CI = Builder.CreateCall(CalleeTy, Callee, Arg);
747 // Make sure the call and the callee agree on calling convention.
748 if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
749 CI->setCallingConv(F->getCallingConv());
750 }
751 }
752
753 FinishFunction();
754 }
755
756 /// generateDestroyHelper - Generates a helper function which, when
757 /// invoked, destroys the given object. The address of the object
758 /// should be in global memory.
759 llvm::Function *CodeGenFunction::generateDestroyHelper(
760 Address addr, QualType type, Destroyer *destroyer,
761 bool useEHCleanupForArray, const VarDecl *VD) {
762 FunctionArgList args;
763 ImplicitParamDecl Dst(getContext(), getContext().VoidPtrTy,
764 ImplicitParamDecl::Other);
765 args.push_back(&Dst);
766
767 const CGFunctionInfo &FI =
768 CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, args);
769 llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
770 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
771 FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
772
773 CurEHLocation = VD->getBeginLoc();
774
775 StartFunction(VD, getContext().VoidTy, fn, FI, args);
776
777 emitDestroy(addr, type, destroyer, useEHCleanupForArray);
778
779 FinishFunction();
780
781 return fn;
782 }