1 //===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This contains code dealing with code generation of C++ declarations
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "CodeGenFunction.h"
15 #include "CGCXXABI.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/Support/Path.h"
22
23 using namespace clang;
24 using namespace CodeGen;
25
EmitDeclInit(CodeGenFunction & CGF,const VarDecl & D,llvm::Constant * DeclPtr)26 static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
27 llvm::Constant *DeclPtr) {
28 assert(D.hasGlobalStorage() && "VarDecl must have global storage!");
29 assert(!D.getType()->isReferenceType() &&
30 "Should not call EmitDeclInit on a reference!");
31
32 ASTContext &Context = CGF.getContext();
33
34 CharUnits alignment = Context.getDeclAlign(&D);
35 QualType type = D.getType();
36 LValue lv = CGF.MakeAddrLValue(DeclPtr, type, alignment);
37
38 const Expr *Init = D.getInit();
39 switch (CGF.getEvaluationKind(type)) {
40 case TEK_Scalar: {
41 CodeGenModule &CGM = CGF.CGM;
42 if (lv.isObjCStrong())
43 CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
44 DeclPtr, D.getTLSKind());
45 else if (lv.isObjCWeak())
46 CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
47 DeclPtr);
48 else
49 CGF.EmitScalarInit(Init, &D, lv, false);
50 return;
51 }
52 case TEK_Complex:
53 CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
54 return;
55 case TEK_Aggregate:
56 CGF.EmitAggExpr(Init, AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
57 AggValueSlot::DoesNotNeedGCBarriers,
58 AggValueSlot::IsNotAliased));
59 return;
60 }
61 llvm_unreachable("bad evaluation kind");
62 }
63
64 /// Emit code to cause the destruction of the given variable with
65 /// static storage duration.
EmitDeclDestroy(CodeGenFunction & CGF,const VarDecl & D,llvm::Constant * addr)66 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
67 llvm::Constant *addr) {
68 CodeGenModule &CGM = CGF.CGM;
69
70 // FIXME: __attribute__((cleanup)) ?
71
72 QualType type = D.getType();
73 QualType::DestructionKind dtorKind = type.isDestructedType();
74
75 switch (dtorKind) {
76 case QualType::DK_none:
77 return;
78
79 case QualType::DK_cxx_destructor:
80 break;
81
82 case QualType::DK_objc_strong_lifetime:
83 case QualType::DK_objc_weak_lifetime:
84 // We don't care about releasing objects during process teardown.
85 assert(!D.getTLSKind() && "should have rejected this");
86 return;
87 }
88
89 llvm::Constant *function;
90 llvm::Constant *argument;
91
92 // Special-case non-array C++ destructors, where there's a function
93 // with the right signature that we can just call.
94 const CXXRecordDecl *record = nullptr;
95 if (dtorKind == QualType::DK_cxx_destructor &&
96 (record = type->getAsCXXRecordDecl())) {
97 assert(!record->hasTrivialDestructor());
98 CXXDestructorDecl *dtor = record->getDestructor();
99
100 function = CGM.getAddrOfCXXStructor(dtor, StructorType::Complete);
101 argument = llvm::ConstantExpr::getBitCast(
102 addr, CGF.getTypes().ConvertType(type)->getPointerTo());
103
104 // Otherwise, the standard logic requires a helper function.
105 } else {
106 function = CodeGenFunction(CGM)
107 .generateDestroyHelper(addr, type, CGF.getDestroyer(dtorKind),
108 CGF.needsEHCleanup(dtorKind), &D);
109 argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
110 }
111
112 CGM.getCXXABI().registerGlobalDtor(CGF, D, function, argument);
113 }
114
115 /// Emit code to cause the variable at the given address to be considered as
116 /// constant from this point onwards.
EmitDeclInvariant(CodeGenFunction & CGF,const VarDecl & D,llvm::Constant * Addr)117 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
118 llvm::Constant *Addr) {
119 // Don't emit the intrinsic if we're not optimizing.
120 if (!CGF.CGM.getCodeGenOpts().OptimizationLevel)
121 return;
122
123 // Grab the llvm.invariant.start intrinsic.
124 llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
125 llvm::Constant *InvariantStart = CGF.CGM.getIntrinsic(InvStartID);
126
127 // Emit a call with the size in bytes of the object.
128 CharUnits WidthChars = CGF.getContext().getTypeSizeInChars(D.getType());
129 uint64_t Width = WidthChars.getQuantity();
130 llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, Width),
131 llvm::ConstantExpr::getBitCast(Addr, CGF.Int8PtrTy)};
132 CGF.Builder.CreateCall(InvariantStart, Args);
133 }
134
EmitCXXGlobalVarDeclInit(const VarDecl & D,llvm::Constant * DeclPtr,bool PerformInit)135 void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
136 llvm::Constant *DeclPtr,
137 bool PerformInit) {
138
139 const Expr *Init = D.getInit();
140 QualType T = D.getType();
141
142 // The address space of a static local variable (DeclPtr) may be different
143 // from the address space of the "this" argument of the constructor. In that
144 // case, we need an addrspacecast before calling the constructor.
145 //
146 // struct StructWithCtor {
147 // __device__ StructWithCtor() {...}
148 // };
149 // __device__ void foo() {
150 // __shared__ StructWithCtor s;
151 // ...
152 // }
153 //
154 // For example, in the above CUDA code, the static local variable s has a
155 // "shared" address space qualifier, but the constructor of StructWithCtor
156 // expects "this" in the "generic" address space.
157 unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
158 unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
159 if (ActualAddrSpace != ExpectedAddrSpace) {
160 llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(T);
161 llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
162 DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
163 }
164
165 if (!T->isReferenceType()) {
166 if (getLangOpts().OpenMP && D.hasAttr<OMPThreadPrivateDeclAttr>())
167 (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
168 &D, DeclPtr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
169 PerformInit, this);
170 if (PerformInit)
171 EmitDeclInit(*this, D, DeclPtr);
172 if (CGM.isTypeConstant(D.getType(), true))
173 EmitDeclInvariant(*this, D, DeclPtr);
174 else
175 EmitDeclDestroy(*this, D, DeclPtr);
176 return;
177 }
178
179 assert(PerformInit && "cannot have constant initializer which needs "
180 "destruction for reference");
181 unsigned Alignment = getContext().getDeclAlign(&D).getQuantity();
182 RValue RV = EmitReferenceBindingToExpr(Init);
183 EmitStoreOfScalar(RV.getScalarVal(), DeclPtr, false, Alignment, T);
184 }
185
186 /// Create a stub function, suitable for being passed to atexit,
187 /// which passes the given address to the given destructor function.
createAtExitStub(const VarDecl & VD,llvm::Constant * dtor,llvm::Constant * addr)188 llvm::Constant *CodeGenFunction::createAtExitStub(const VarDecl &VD,
189 llvm::Constant *dtor,
190 llvm::Constant *addr) {
191 // Get the destructor function type, void(*)(void).
192 llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
193 SmallString<256> FnName;
194 {
195 llvm::raw_svector_ostream Out(FnName);
196 CGM.getCXXABI().getMangleContext().mangleDynamicAtExitDestructor(&VD, Out);
197 }
198 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
199 VD.getLocation());
200
201 CodeGenFunction CGF(CGM);
202
203 CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn,
204 CGM.getTypes().arrangeNullaryFunction(), FunctionArgList());
205
206 llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
207
208 // Make sure the call and the callee agree on calling convention.
209 if (llvm::Function *dtorFn =
210 dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
211 call->setCallingConv(dtorFn->getCallingConv());
212
213 CGF.FinishFunction();
214
215 return fn;
216 }
217
218 /// Register a global destructor using the C atexit runtime function.
registerGlobalDtorWithAtExit(const VarDecl & VD,llvm::Constant * dtor,llvm::Constant * addr)219 void CodeGenFunction::registerGlobalDtorWithAtExit(const VarDecl &VD,
220 llvm::Constant *dtor,
221 llvm::Constant *addr) {
222 // Create a function which calls the destructor.
223 llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
224
225 // extern "C" int atexit(void (*f)(void));
226 llvm::FunctionType *atexitTy =
227 llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
228
229 llvm::Constant *atexit =
230 CGM.CreateRuntimeFunction(atexitTy, "atexit");
231 if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
232 atexitFn->setDoesNotThrow();
233
234 EmitNounwindRuntimeCall(atexit, dtorStub);
235 }
236
EmitCXXGuardedInit(const VarDecl & D,llvm::GlobalVariable * DeclPtr,bool PerformInit)237 void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
238 llvm::GlobalVariable *DeclPtr,
239 bool PerformInit) {
240 // If we've been asked to forbid guard variables, emit an error now.
241 // This diagnostic is hard-coded for Darwin's use case; we can find
242 // better phrasing if someone else needs it.
243 if (CGM.getCodeGenOpts().ForbidGuardVariables)
244 CGM.Error(D.getLocation(),
245 "this initialization requires a guard variable, which "
246 "the kernel does not support");
247
248 CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
249 }
250
CreateGlobalInitOrDestructFunction(llvm::FunctionType * FTy,const Twine & Name,SourceLocation Loc,bool TLS)251 llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
252 llvm::FunctionType *FTy, const Twine &Name, SourceLocation Loc, bool TLS) {
253 llvm::Function *Fn =
254 llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
255 Name, &getModule());
256 if (!getLangOpts().AppleKext && !TLS) {
257 // Set the section if needed.
258 if (const char *Section = getTarget().getStaticInitSectionSpecifier())
259 Fn->setSection(Section);
260 }
261
262 Fn->setCallingConv(getRuntimeCC());
263
264 if (!getLangOpts().Exceptions)
265 Fn->setDoesNotThrow();
266
267 if (!isInSanitizerBlacklist(Fn, Loc)) {
268 if (getLangOpts().Sanitize.has(SanitizerKind::Address))
269 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
270 if (getLangOpts().Sanitize.has(SanitizerKind::Thread))
271 Fn->addFnAttr(llvm::Attribute::SanitizeThread);
272 if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
273 Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
274 }
275
276 return Fn;
277 }
278
279 /// Create a global pointer to a function that will initialize a global
280 /// variable. The user has requested that this pointer be emitted in a specific
281 /// section.
EmitPointerToInitFunc(const VarDecl * D,llvm::GlobalVariable * GV,llvm::Function * InitFunc,InitSegAttr * ISA)282 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
283 llvm::GlobalVariable *GV,
284 llvm::Function *InitFunc,
285 InitSegAttr *ISA) {
286 llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
287 TheModule, InitFunc->getType(), /*isConstant=*/true,
288 llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
289 PtrArray->setSection(ISA->getSection());
290 addUsedGlobal(PtrArray);
291
292 // If the GV is already in a comdat group, then we have to join it.
293 if (llvm::Comdat *C = GV->getComdat())
294 PtrArray->setComdat(C);
295 }
296
297 void
EmitCXXGlobalVarDeclInitFunc(const VarDecl * D,llvm::GlobalVariable * Addr,bool PerformInit)298 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
299 llvm::GlobalVariable *Addr,
300 bool PerformInit) {
301 // Check if we've already initialized this decl.
302 auto I = DelayedCXXInitPosition.find(D);
303 if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
304 return;
305
306 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
307 SmallString<256> FnName;
308 {
309 llvm::raw_svector_ostream Out(FnName);
310 getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
311 }
312
313 // Create a variable initialization function.
314 llvm::Function *Fn =
315 CreateGlobalInitOrDestructFunction(FTy, FnName.str(), D->getLocation());
316
317 auto *ISA = D->getAttr<InitSegAttr>();
318 CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
319 PerformInit);
320
321 llvm::GlobalVariable *COMDATKey =
322 supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
323
324 if (D->getTLSKind()) {
325 // FIXME: Should we support init_priority for thread_local?
326 // FIXME: Ideally, initialization of instantiated thread_local static data
327 // members of class templates should not trigger initialization of other
328 // entities in the TU.
329 // FIXME: We only need to register one __cxa_thread_atexit function for the
330 // entire TU.
331 CXXThreadLocalInits.push_back(Fn);
332 CXXThreadLocalInitVars.push_back(Addr);
333 } else if (PerformInit && ISA) {
334 EmitPointerToInitFunc(D, Addr, Fn, ISA);
335 } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
336 OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
337 PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
338 } else if (isTemplateInstantiation(D->getTemplateSpecializationKind())) {
339 // C++ [basic.start.init]p2:
340 // Definitions of explicitly specialized class template static data
341 // members have ordered initialization. Other class template static data
342 // members (i.e., implicitly or explicitly instantiated specializations)
343 // have unordered initialization.
344 //
345 // As a consequence, we can put them into their own llvm.global_ctors entry.
346 //
347 // If the global is externally visible, put the initializer into a COMDAT
348 // group with the global being initialized. On most platforms, this is a
349 // minor startup time optimization. In the MS C++ ABI, there are no guard
350 // variables, so this COMDAT key is required for correctness.
351 AddGlobalCtor(Fn, 65535, COMDATKey);
352 } else if (D->hasAttr<SelectAnyAttr>()) {
353 // SelectAny globals will be comdat-folded. Put the initializer into a
354 // COMDAT group associated with the global, so the initializers get folded
355 // too.
356 AddGlobalCtor(Fn, 65535, COMDATKey);
357 } else {
358 I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
359 if (I == DelayedCXXInitPosition.end()) {
360 CXXGlobalInits.push_back(Fn);
361 } else if (I->second != ~0U) {
362 assert(I->second < CXXGlobalInits.size() &&
363 CXXGlobalInits[I->second] == nullptr);
364 CXXGlobalInits[I->second] = Fn;
365 }
366 }
367
368 // Remember that we already emitted the initializer for this global.
369 DelayedCXXInitPosition[D] = ~0U;
370 }
371
EmitCXXThreadLocalInitFunc()372 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
373 getCXXABI().EmitThreadLocalInitFuncs(
374 *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
375
376 CXXThreadLocalInits.clear();
377 CXXThreadLocalInitVars.clear();
378 CXXThreadLocals.clear();
379 }
380
381 void
EmitCXXGlobalInitFunc()382 CodeGenModule::EmitCXXGlobalInitFunc() {
383 while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
384 CXXGlobalInits.pop_back();
385
386 if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
387 return;
388
389 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
390
391
392 // Create our global initialization function.
393 if (!PrioritizedCXXGlobalInits.empty()) {
394 SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
395 llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
396 PrioritizedCXXGlobalInits.end());
397 // Iterate over "chunks" of ctors with same priority and emit each chunk
398 // into separate function. Note - everything is sorted first by priority,
399 // second - by lex order, so we emit ctor functions in proper order.
400 for (SmallVectorImpl<GlobalInitData >::iterator
401 I = PrioritizedCXXGlobalInits.begin(),
402 E = PrioritizedCXXGlobalInits.end(); I != E; ) {
403 SmallVectorImpl<GlobalInitData >::iterator
404 PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
405
406 LocalCXXGlobalInits.clear();
407 unsigned Priority = I->first.priority;
408 // Compute the function suffix from priority. Prepend with zeroes to make
409 // sure the function names are also ordered as priorities.
410 std::string PrioritySuffix = llvm::utostr(Priority);
411 // Priority is always <= 65535 (enforced by sema).
412 PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
413 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
414 FTy, "_GLOBAL__I_" + PrioritySuffix);
415
416 for (; I < PrioE; ++I)
417 LocalCXXGlobalInits.push_back(I->second);
418
419 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
420 AddGlobalCtor(Fn, Priority);
421 }
422 }
423
424 SmallString<128> FileName;
425 SourceManager &SM = Context.getSourceManager();
426 if (const FileEntry *MainFile = SM.getFileEntryForID(SM.getMainFileID())) {
427 // Include the filename in the symbol name. Including "sub_" matches gcc and
428 // makes sure these symbols appear lexicographically behind the symbols with
429 // priority emitted above.
430 FileName = llvm::sys::path::filename(MainFile->getName());
431 } else {
432 FileName = SmallString<128>("<null>");
433 }
434
435 for (size_t i = 0; i < FileName.size(); ++i) {
436 // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
437 // to be the set of C preprocessing numbers.
438 if (!isPreprocessingNumberBody(FileName[i]))
439 FileName[i] = '_';
440 }
441
442 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
443 FTy, llvm::Twine("_GLOBAL__sub_I_", FileName));
444
445 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
446 AddGlobalCtor(Fn);
447
448 CXXGlobalInits.clear();
449 PrioritizedCXXGlobalInits.clear();
450 }
451
EmitCXXGlobalDtorFunc()452 void CodeGenModule::EmitCXXGlobalDtorFunc() {
453 if (CXXGlobalDtors.empty())
454 return;
455
456 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
457
458 // Create our global destructor function.
459 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a");
460
461 CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
462 AddGlobalDtor(Fn);
463 }
464
465 /// Emit the code necessary to initialize the given global variable.
GenerateCXXGlobalVarDeclInitFunc(llvm::Function * Fn,const VarDecl * D,llvm::GlobalVariable * Addr,bool PerformInit)466 void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
467 const VarDecl *D,
468 llvm::GlobalVariable *Addr,
469 bool PerformInit) {
470 // Check if we need to emit debug info for variable initializer.
471 if (D->hasAttr<NoDebugAttr>())
472 DebugInfo = nullptr; // disable debug info indefinitely for this function
473
474 CurEHLocation = D->getLocStart();
475
476 StartFunction(GlobalDecl(D), getContext().VoidTy, Fn,
477 getTypes().arrangeNullaryFunction(),
478 FunctionArgList(), D->getLocation(),
479 D->getInit()->getExprLoc());
480
481 // Use guarded initialization if the global variable is weak. This
482 // occurs for, e.g., instantiated static data members and
483 // definitions explicitly marked weak.
484 if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
485 EmitCXXGuardedInit(*D, Addr, PerformInit);
486 } else {
487 EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
488 }
489
490 FinishFunction();
491 }
492
493 void
GenerateCXXGlobalInitFunc(llvm::Function * Fn,ArrayRef<llvm::Function * > Decls,llvm::GlobalVariable * Guard)494 CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
495 ArrayRef<llvm::Function *> Decls,
496 llvm::GlobalVariable *Guard) {
497 {
498 auto NL = ApplyDebugLocation::CreateEmpty(*this);
499 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
500 getTypes().arrangeNullaryFunction(), FunctionArgList());
501 // Emit an artificial location for this function.
502 auto AL = ApplyDebugLocation::CreateArtificial(*this);
503
504 llvm::BasicBlock *ExitBlock = nullptr;
505 if (Guard) {
506 // If we have a guard variable, check whether we've already performed
507 // these initializations. This happens for TLS initialization functions.
508 llvm::Value *GuardVal = Builder.CreateLoad(Guard);
509 llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
510 "guard.uninitialized");
511 // Mark as initialized before initializing anything else. If the
512 // initializers use previously-initialized thread_local vars, that's
513 // probably supposed to be OK, but the standard doesn't say.
514 Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
515 llvm::BasicBlock *InitBlock = createBasicBlock("init");
516 ExitBlock = createBasicBlock("exit");
517 Builder.CreateCondBr(Uninit, InitBlock, ExitBlock);
518 EmitBlock(InitBlock);
519 }
520
521 RunCleanupsScope Scope(*this);
522
523 // When building in Objective-C++ ARC mode, create an autorelease pool
524 // around the global initializers.
525 if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
526 llvm::Value *token = EmitObjCAutoreleasePoolPush();
527 EmitObjCAutoreleasePoolCleanup(token);
528 }
529
530 for (unsigned i = 0, e = Decls.size(); i != e; ++i)
531 if (Decls[i])
532 EmitRuntimeCall(Decls[i]);
533
534 Scope.ForceCleanup();
535
536 if (ExitBlock) {
537 Builder.CreateBr(ExitBlock);
538 EmitBlock(ExitBlock);
539 }
540 }
541
542 FinishFunction();
543 }
544
GenerateCXXGlobalDtorsFunc(llvm::Function * Fn,const std::vector<std::pair<llvm::WeakVH,llvm::Constant * >> & DtorsAndObjects)545 void CodeGenFunction::GenerateCXXGlobalDtorsFunc(llvm::Function *Fn,
546 const std::vector<std::pair<llvm::WeakVH, llvm::Constant*> >
547 &DtorsAndObjects) {
548 {
549 auto NL = ApplyDebugLocation::CreateEmpty(*this);
550 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
551 getTypes().arrangeNullaryFunction(), FunctionArgList());
552 // Emit an artificial location for this function.
553 auto AL = ApplyDebugLocation::CreateArtificial(*this);
554
555 // Emit the dtors, in reverse order from construction.
556 for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
557 llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
558 llvm::CallInst *CI = Builder.CreateCall(Callee,
559 DtorsAndObjects[e - i - 1].second);
560 // Make sure the call and the callee agree on calling convention.
561 if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
562 CI->setCallingConv(F->getCallingConv());
563 }
564 }
565
566 FinishFunction();
567 }
568
569 /// generateDestroyHelper - Generates a helper function which, when
570 /// invoked, destroys the given object.
generateDestroyHelper(llvm::Constant * addr,QualType type,Destroyer * destroyer,bool useEHCleanupForArray,const VarDecl * VD)571 llvm::Function *CodeGenFunction::generateDestroyHelper(
572 llvm::Constant *addr, QualType type, Destroyer *destroyer,
573 bool useEHCleanupForArray, const VarDecl *VD) {
574 FunctionArgList args;
575 ImplicitParamDecl dst(getContext(), nullptr, SourceLocation(), nullptr,
576 getContext().VoidPtrTy);
577 args.push_back(&dst);
578
579 const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration(
580 getContext().VoidTy, args, FunctionType::ExtInfo(), /*variadic=*/false);
581 llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
582 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
583 FTy, "__cxx_global_array_dtor", VD->getLocation());
584
585 CurEHLocation = VD->getLocStart();
586
587 StartFunction(VD, getContext().VoidTy, fn, FI, args);
588
589 emitDestroy(addr, type, destroyer, useEHCleanupForArray);
590
591 FinishFunction();
592
593 return fn;
594 }
595