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,ConstantAddress DeclPtr)26 static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
27 ConstantAddress 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 QualType type = D.getType();
33 LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
34
35 const Expr *Init = D.getInit();
36 switch (CGF.getEvaluationKind(type)) {
37 case TEK_Scalar: {
38 CodeGenModule &CGM = CGF.CGM;
39 if (lv.isObjCStrong())
40 CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
41 DeclPtr, D.getTLSKind());
42 else if (lv.isObjCWeak())
43 CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
44 DeclPtr);
45 else
46 CGF.EmitScalarInit(Init, &D, lv, false);
47 return;
48 }
49 case TEK_Complex:
50 CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
51 return;
52 case TEK_Aggregate:
53 CGF.EmitAggExpr(Init, AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
54 AggValueSlot::DoesNotNeedGCBarriers,
55 AggValueSlot::IsNotAliased));
56 return;
57 }
58 llvm_unreachable("bad evaluation kind");
59 }
60
61 /// Emit code to cause the destruction of the given variable with
62 /// static storage duration.
EmitDeclDestroy(CodeGenFunction & CGF,const VarDecl & D,ConstantAddress addr)63 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
64 ConstantAddress addr) {
65 CodeGenModule &CGM = CGF.CGM;
66
67 // FIXME: __attribute__((cleanup)) ?
68
69 QualType type = D.getType();
70 QualType::DestructionKind dtorKind = type.isDestructedType();
71
72 switch (dtorKind) {
73 case QualType::DK_none:
74 return;
75
76 case QualType::DK_cxx_destructor:
77 break;
78
79 case QualType::DK_objc_strong_lifetime:
80 case QualType::DK_objc_weak_lifetime:
81 // We don't care about releasing objects during process teardown.
82 assert(!D.getTLSKind() && "should have rejected this");
83 return;
84 }
85
86 llvm::Constant *function;
87 llvm::Constant *argument;
88
89 // Special-case non-array C++ destructors, where there's a function
90 // with the right signature that we can just call.
91 const CXXRecordDecl *record = nullptr;
92 if (dtorKind == QualType::DK_cxx_destructor &&
93 (record = type->getAsCXXRecordDecl())) {
94 assert(!record->hasTrivialDestructor());
95 CXXDestructorDecl *dtor = record->getDestructor();
96
97 function = CGM.getAddrOfCXXStructor(dtor, StructorType::Complete);
98 argument = llvm::ConstantExpr::getBitCast(
99 addr.getPointer(), CGF.getTypes().ConvertType(type)->getPointerTo());
100
101 // Otherwise, the standard logic requires a helper function.
102 } else {
103 function = CodeGenFunction(CGM)
104 .generateDestroyHelper(addr, type, CGF.getDestroyer(dtorKind),
105 CGF.needsEHCleanup(dtorKind), &D);
106 argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
107 }
108
109 CGM.getCXXABI().registerGlobalDtor(CGF, D, function, argument);
110 }
111
112 /// Emit code to cause the variable at the given address to be considered as
113 /// constant from this point onwards.
EmitDeclInvariant(CodeGenFunction & CGF,const VarDecl & D,llvm::Constant * Addr)114 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
115 llvm::Constant *Addr) {
116 // Don't emit the intrinsic if we're not optimizing.
117 if (!CGF.CGM.getCodeGenOpts().OptimizationLevel)
118 return;
119
120 // Grab the llvm.invariant.start intrinsic.
121 llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
122 llvm::Constant *InvariantStart = CGF.CGM.getIntrinsic(InvStartID);
123
124 // Emit a call with the size in bytes of the object.
125 CharUnits WidthChars = CGF.getContext().getTypeSizeInChars(D.getType());
126 uint64_t Width = WidthChars.getQuantity();
127 llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, Width),
128 llvm::ConstantExpr::getBitCast(Addr, CGF.Int8PtrTy)};
129 CGF.Builder.CreateCall(InvariantStart, Args);
130 }
131
EmitCXXGlobalVarDeclInit(const VarDecl & D,llvm::Constant * DeclPtr,bool PerformInit)132 void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
133 llvm::Constant *DeclPtr,
134 bool PerformInit) {
135
136 const Expr *Init = D.getInit();
137 QualType T = D.getType();
138
139 // The address space of a static local variable (DeclPtr) may be different
140 // from the address space of the "this" argument of the constructor. In that
141 // case, we need an addrspacecast before calling the constructor.
142 //
143 // struct StructWithCtor {
144 // __device__ StructWithCtor() {...}
145 // };
146 // __device__ void foo() {
147 // __shared__ StructWithCtor s;
148 // ...
149 // }
150 //
151 // For example, in the above CUDA code, the static local variable s has a
152 // "shared" address space qualifier, but the constructor of StructWithCtor
153 // expects "this" in the "generic" address space.
154 unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
155 unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
156 if (ActualAddrSpace != ExpectedAddrSpace) {
157 llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(T);
158 llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
159 DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
160 }
161
162 ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
163
164 if (!T->isReferenceType()) {
165 if (getLangOpts().OpenMP && D.hasAttr<OMPThreadPrivateDeclAttr>())
166 (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
167 &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
168 PerformInit, this);
169 if (PerformInit)
170 EmitDeclInit(*this, D, DeclAddr);
171 if (CGM.isTypeConstant(D.getType(), true))
172 EmitDeclInvariant(*this, D, DeclPtr);
173 else
174 EmitDeclDestroy(*this, D, DeclAddr);
175 return;
176 }
177
178 assert(PerformInit && "cannot have constant initializer which needs "
179 "destruction for reference");
180 RValue RV = EmitReferenceBindingToExpr(Init);
181 EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
182 }
183
184 /// Create a stub function, suitable for being passed to atexit,
185 /// which passes the given address to the given destructor function.
createAtExitStub(const VarDecl & VD,llvm::Constant * dtor,llvm::Constant * addr)186 llvm::Constant *CodeGenFunction::createAtExitStub(const VarDecl &VD,
187 llvm::Constant *dtor,
188 llvm::Constant *addr) {
189 // Get the destructor function type, void(*)(void).
190 llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
191 SmallString<256> FnName;
192 {
193 llvm::raw_svector_ostream Out(FnName);
194 CGM.getCXXABI().getMangleContext().mangleDynamicAtExitDestructor(&VD, Out);
195 }
196
197 const CGFunctionInfo &FI = CGM.getTypes().arrangeNullaryFunction();
198 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
199 FI,
200 VD.getLocation());
201
202 CodeGenFunction CGF(CGM);
203
204 CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn, FI, 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,const CGFunctionInfo & FI,SourceLocation Loc,bool TLS)251 llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
252 llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
253 SourceLocation Loc, bool TLS) {
254 llvm::Function *Fn =
255 llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
256 Name, &getModule());
257 if (!getLangOpts().AppleKext && !TLS) {
258 // Set the section if needed.
259 if (const char *Section = getTarget().getStaticInitSectionSpecifier())
260 Fn->setSection(Section);
261 }
262
263 SetInternalFunctionAttributes(nullptr, Fn, FI);
264
265 Fn->setCallingConv(getRuntimeCC());
266
267 if (!getLangOpts().Exceptions)
268 Fn->setDoesNotThrow();
269
270 if (!isInSanitizerBlacklist(Fn, Loc)) {
271 if (getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
272 SanitizerKind::KernelAddress))
273 Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
274 if (getLangOpts().Sanitize.has(SanitizerKind::Thread))
275 Fn->addFnAttr(llvm::Attribute::SanitizeThread);
276 if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
277 Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
278 if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack))
279 Fn->addFnAttr(llvm::Attribute::SafeStack);
280 }
281
282 return Fn;
283 }
284
285 /// Create a global pointer to a function that will initialize a global
286 /// variable. The user has requested that this pointer be emitted in a specific
287 /// section.
EmitPointerToInitFunc(const VarDecl * D,llvm::GlobalVariable * GV,llvm::Function * InitFunc,InitSegAttr * ISA)288 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
289 llvm::GlobalVariable *GV,
290 llvm::Function *InitFunc,
291 InitSegAttr *ISA) {
292 llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
293 TheModule, InitFunc->getType(), /*isConstant=*/true,
294 llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
295 PtrArray->setSection(ISA->getSection());
296 addUsedGlobal(PtrArray);
297
298 // If the GV is already in a comdat group, then we have to join it.
299 if (llvm::Comdat *C = GV->getComdat())
300 PtrArray->setComdat(C);
301 }
302
303 void
EmitCXXGlobalVarDeclInitFunc(const VarDecl * D,llvm::GlobalVariable * Addr,bool PerformInit)304 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
305 llvm::GlobalVariable *Addr,
306 bool PerformInit) {
307 // Check if we've already initialized this decl.
308 auto I = DelayedCXXInitPosition.find(D);
309 if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
310 return;
311
312 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
313 SmallString<256> FnName;
314 {
315 llvm::raw_svector_ostream Out(FnName);
316 getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
317 }
318
319 // Create a variable initialization function.
320 llvm::Function *Fn =
321 CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
322 getTypes().arrangeNullaryFunction(),
323 D->getLocation());
324
325 auto *ISA = D->getAttr<InitSegAttr>();
326 CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
327 PerformInit);
328
329 llvm::GlobalVariable *COMDATKey =
330 supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
331
332 if (D->getTLSKind()) {
333 // FIXME: Should we support init_priority for thread_local?
334 // FIXME: Ideally, initialization of instantiated thread_local static data
335 // members of class templates should not trigger initialization of other
336 // entities in the TU.
337 // FIXME: We only need to register one __cxa_thread_atexit function for the
338 // entire TU.
339 CXXThreadLocalInits.push_back(Fn);
340 CXXThreadLocalInitVars.push_back(D);
341 } else if (PerformInit && ISA) {
342 EmitPointerToInitFunc(D, Addr, Fn, ISA);
343 } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
344 OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
345 PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
346 } else if (isTemplateInstantiation(D->getTemplateSpecializationKind())) {
347 // C++ [basic.start.init]p2:
348 // Definitions of explicitly specialized class template static data
349 // members have ordered initialization. Other class template static data
350 // members (i.e., implicitly or explicitly instantiated specializations)
351 // have unordered initialization.
352 //
353 // As a consequence, we can put them into their own llvm.global_ctors entry.
354 //
355 // If the global is externally visible, put the initializer into a COMDAT
356 // group with the global being initialized. On most platforms, this is a
357 // minor startup time optimization. In the MS C++ ABI, there are no guard
358 // variables, so this COMDAT key is required for correctness.
359 AddGlobalCtor(Fn, 65535, COMDATKey);
360 } else if (D->hasAttr<SelectAnyAttr>()) {
361 // SelectAny globals will be comdat-folded. Put the initializer into a
362 // COMDAT group associated with the global, so the initializers get folded
363 // too.
364 AddGlobalCtor(Fn, 65535, COMDATKey);
365 } else {
366 I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
367 if (I == DelayedCXXInitPosition.end()) {
368 CXXGlobalInits.push_back(Fn);
369 } else if (I->second != ~0U) {
370 assert(I->second < CXXGlobalInits.size() &&
371 CXXGlobalInits[I->second] == nullptr);
372 CXXGlobalInits[I->second] = Fn;
373 }
374 }
375
376 // Remember that we already emitted the initializer for this global.
377 DelayedCXXInitPosition[D] = ~0U;
378 }
379
EmitCXXThreadLocalInitFunc()380 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
381 getCXXABI().EmitThreadLocalInitFuncs(
382 *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
383
384 CXXThreadLocalInits.clear();
385 CXXThreadLocalInitVars.clear();
386 CXXThreadLocals.clear();
387 }
388
389 void
EmitCXXGlobalInitFunc()390 CodeGenModule::EmitCXXGlobalInitFunc() {
391 while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
392 CXXGlobalInits.pop_back();
393
394 if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
395 return;
396
397 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
398 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
399
400 // Create our global initialization function.
401 if (!PrioritizedCXXGlobalInits.empty()) {
402 SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
403 llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
404 PrioritizedCXXGlobalInits.end());
405 // Iterate over "chunks" of ctors with same priority and emit each chunk
406 // into separate function. Note - everything is sorted first by priority,
407 // second - by lex order, so we emit ctor functions in proper order.
408 for (SmallVectorImpl<GlobalInitData >::iterator
409 I = PrioritizedCXXGlobalInits.begin(),
410 E = PrioritizedCXXGlobalInits.end(); I != E; ) {
411 SmallVectorImpl<GlobalInitData >::iterator
412 PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
413
414 LocalCXXGlobalInits.clear();
415 unsigned Priority = I->first.priority;
416 // Compute the function suffix from priority. Prepend with zeroes to make
417 // sure the function names are also ordered as priorities.
418 std::string PrioritySuffix = llvm::utostr(Priority);
419 // Priority is always <= 65535 (enforced by sema).
420 PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
421 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
422 FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
423
424 for (; I < PrioE; ++I)
425 LocalCXXGlobalInits.push_back(I->second);
426
427 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
428 AddGlobalCtor(Fn, Priority);
429 }
430 PrioritizedCXXGlobalInits.clear();
431 }
432
433 SmallString<128> FileName;
434 SourceManager &SM = Context.getSourceManager();
435 if (const FileEntry *MainFile = SM.getFileEntryForID(SM.getMainFileID())) {
436 // Include the filename in the symbol name. Including "sub_" matches gcc and
437 // makes sure these symbols appear lexicographically behind the symbols with
438 // priority emitted above.
439 FileName = llvm::sys::path::filename(MainFile->getName());
440 } else {
441 FileName = "<null>";
442 }
443
444 for (size_t i = 0; i < FileName.size(); ++i) {
445 // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
446 // to be the set of C preprocessing numbers.
447 if (!isPreprocessingNumberBody(FileName[i]))
448 FileName[i] = '_';
449 }
450
451 llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
452 FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
453
454 CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
455 AddGlobalCtor(Fn);
456
457 CXXGlobalInits.clear();
458 }
459
EmitCXXGlobalDtorFunc()460 void CodeGenModule::EmitCXXGlobalDtorFunc() {
461 if (CXXGlobalDtors.empty())
462 return;
463
464 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
465
466 // Create our global destructor function.
467 const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
468 llvm::Function *Fn =
469 CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
470
471 CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
472 AddGlobalDtor(Fn);
473 }
474
475 /// Emit the code necessary to initialize the given global variable.
GenerateCXXGlobalVarDeclInitFunc(llvm::Function * Fn,const VarDecl * D,llvm::GlobalVariable * Addr,bool PerformInit)476 void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
477 const VarDecl *D,
478 llvm::GlobalVariable *Addr,
479 bool PerformInit) {
480 // Check if we need to emit debug info for variable initializer.
481 if (D->hasAttr<NoDebugAttr>())
482 DebugInfo = nullptr; // disable debug info indefinitely for this function
483
484 CurEHLocation = D->getLocStart();
485
486 StartFunction(GlobalDecl(D), getContext().VoidTy, Fn,
487 getTypes().arrangeNullaryFunction(),
488 FunctionArgList(), D->getLocation(),
489 D->getInit()->getExprLoc());
490
491 // Use guarded initialization if the global variable is weak. This
492 // occurs for, e.g., instantiated static data members and
493 // definitions explicitly marked weak.
494 if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
495 EmitCXXGuardedInit(*D, Addr, PerformInit);
496 } else {
497 EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
498 }
499
500 FinishFunction();
501 }
502
503 void
GenerateCXXGlobalInitFunc(llvm::Function * Fn,ArrayRef<llvm::Function * > Decls,Address Guard)504 CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
505 ArrayRef<llvm::Function *> Decls,
506 Address Guard) {
507 {
508 auto NL = ApplyDebugLocation::CreateEmpty(*this);
509 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
510 getTypes().arrangeNullaryFunction(), FunctionArgList());
511 // Emit an artificial location for this function.
512 auto AL = ApplyDebugLocation::CreateArtificial(*this);
513
514 llvm::BasicBlock *ExitBlock = nullptr;
515 if (Guard.isValid()) {
516 // If we have a guard variable, check whether we've already performed
517 // these initializations. This happens for TLS initialization functions.
518 llvm::Value *GuardVal = Builder.CreateLoad(Guard);
519 llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
520 "guard.uninitialized");
521 llvm::BasicBlock *InitBlock = createBasicBlock("init");
522 ExitBlock = createBasicBlock("exit");
523 Builder.CreateCondBr(Uninit, InitBlock, ExitBlock);
524 EmitBlock(InitBlock);
525 // Mark as initialized before initializing anything else. If the
526 // initializers use previously-initialized thread_local vars, that's
527 // probably supposed to be OK, but the standard doesn't say.
528 Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
529 }
530
531 RunCleanupsScope Scope(*this);
532
533 // When building in Objective-C++ ARC mode, create an autorelease pool
534 // around the global initializers.
535 if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
536 llvm::Value *token = EmitObjCAutoreleasePoolPush();
537 EmitObjCAutoreleasePoolCleanup(token);
538 }
539
540 for (unsigned i = 0, e = Decls.size(); i != e; ++i)
541 if (Decls[i])
542 EmitRuntimeCall(Decls[i]);
543
544 Scope.ForceCleanup();
545
546 if (ExitBlock) {
547 Builder.CreateBr(ExitBlock);
548 EmitBlock(ExitBlock);
549 }
550 }
551
552 FinishFunction();
553 }
554
GenerateCXXGlobalDtorsFunc(llvm::Function * Fn,const std::vector<std::pair<llvm::WeakVH,llvm::Constant * >> & DtorsAndObjects)555 void CodeGenFunction::GenerateCXXGlobalDtorsFunc(llvm::Function *Fn,
556 const std::vector<std::pair<llvm::WeakVH, llvm::Constant*> >
557 &DtorsAndObjects) {
558 {
559 auto NL = ApplyDebugLocation::CreateEmpty(*this);
560 StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
561 getTypes().arrangeNullaryFunction(), FunctionArgList());
562 // Emit an artificial location for this function.
563 auto AL = ApplyDebugLocation::CreateArtificial(*this);
564
565 // Emit the dtors, in reverse order from construction.
566 for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
567 llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
568 llvm::CallInst *CI = Builder.CreateCall(Callee,
569 DtorsAndObjects[e - i - 1].second);
570 // Make sure the call and the callee agree on calling convention.
571 if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
572 CI->setCallingConv(F->getCallingConv());
573 }
574 }
575
576 FinishFunction();
577 }
578
579 /// generateDestroyHelper - Generates a helper function which, when
580 /// invoked, destroys the given object. The address of the object
581 /// should be in global memory.
generateDestroyHelper(Address addr,QualType type,Destroyer * destroyer,bool useEHCleanupForArray,const VarDecl * VD)582 llvm::Function *CodeGenFunction::generateDestroyHelper(
583 Address addr, QualType type, Destroyer *destroyer,
584 bool useEHCleanupForArray, const VarDecl *VD) {
585 FunctionArgList args;
586 ImplicitParamDecl dst(getContext(), nullptr, SourceLocation(), nullptr,
587 getContext().VoidPtrTy);
588 args.push_back(&dst);
589
590 const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration(
591 getContext().VoidTy, args, FunctionType::ExtInfo(), /*variadic=*/false);
592 llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
593 llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
594 FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
595
596 CurEHLocation = VD->getLocStart();
597
598 StartFunction(VD, getContext().VoidTy, fn, FI, args);
599
600 emitDestroy(addr, type, destroyer, useEHCleanupForArray);
601
602 FinishFunction();
603
604 return fn;
605 }
606