clang  8.0.0svn
CGDeclCXX.cpp
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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"
19 #include "llvm/ADT/StringExtras.h"
20 #include "llvm/IR/Intrinsics.h"
21 #include "llvm/IR/MDBuilder.h"
22 #include "llvm/Support/Path.h"
23 
24 using namespace clang;
25 using namespace CodeGen;
26 
27 static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
28  ConstantAddress DeclPtr) {
29  assert(
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!");
35 
36  QualType type = D.getType();
37  LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
38 
39  const Expr *Init = D.getInit();
40  switch (CGF.getEvaluationKind(type)) {
41  case TEK_Scalar: {
42  CodeGenModule &CGM = CGF.CGM;
43  if (lv.isObjCStrong())
45  DeclPtr, D.getTLSKind());
46  else if (lv.isObjCWeak())
48  DeclPtr);
49  else
50  CGF.EmitScalarInit(Init, &D, lv, false);
51  return;
52  }
53  case TEK_Complex:
54  CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
55  return;
56  case TEK_Aggregate:
61  return;
62  }
63  llvm_unreachable("bad evaluation kind");
64 }
65 
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  if (D.isNoDestroy(CGF.getContext()))
77  return;
78 
79  CodeGenModule &CGM = CGF.CGM;
80 
81  // FIXME: __attribute__((cleanup)) ?
82 
83  QualType Type = D.getType();
85 
86  switch (DtorKind) {
87  case QualType::DK_none:
88  return;
89 
91  break;
92 
96  // We don't care about releasing objects during process teardown.
97  assert(!D.getTLSKind() && "should have rejected this");
98  return;
99  }
100 
101  llvm::Constant *Func;
102  llvm::Constant *Argument;
103 
104  // Special-case non-array C++ destructors, if they have the right signature.
105  // Under some ABIs, destructors return this instead of void, and cannot be
106  // passed directly to __cxa_atexit if the target does not allow this
107  // mismatch.
108  const CXXRecordDecl *Record = Type->getAsCXXRecordDecl();
109  bool CanRegisterDestructor =
110  Record && (!CGM.getCXXABI().HasThisReturn(
111  GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
113  // If __cxa_atexit is disabled via a flag, a different helper function is
114  // generated elsewhere which uses atexit instead, and it takes the destructor
115  // directly.
116  bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
117  if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
118  assert(!Record->hasTrivialDestructor());
119  CXXDestructorDecl *Dtor = Record->getDestructor();
120 
122  Argument = llvm::ConstantExpr::getBitCast(
123  Addr.getPointer(), CGF.getTypes().ConvertType(Type)->getPointerTo());
124 
125  // Otherwise, the standard logic requires a helper function.
126  } else {
127  Func = CodeGenFunction(CGM)
128  .generateDestroyHelper(Addr, Type, CGF.getDestroyer(DtorKind),
129  CGF.needsEHCleanup(DtorKind), &D);
130  Argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
131  }
132 
133  CGM.getCXXABI().registerGlobalDtor(CGF, D, Func, Argument);
134 }
135 
136 /// Emit code to cause the variable at the given address to be considered as
137 /// constant from this point onwards.
138 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
139  llvm::Constant *Addr) {
140  return CGF.EmitInvariantStart(
141  Addr, CGF.getContext().getTypeSizeInChars(D.getType()));
142 }
143 
144 void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
145  // Do not emit the intrinsic if we're not optimizing.
146  if (!CGM.getCodeGenOpts().OptimizationLevel)
147  return;
148 
149  // Grab the llvm.invariant.start intrinsic.
150  llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
151  // Overloaded address space type.
152  llvm::Type *ObjectPtr[1] = {Int8PtrTy};
153  llvm::Constant *InvariantStart = CGM.getIntrinsic(InvStartID, ObjectPtr);
154 
155  // Emit a call with the size in bytes of the object.
156  uint64_t Width = Size.getQuantity();
157  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
158  llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
159  Builder.CreateCall(InvariantStart, Args);
160 }
161 
163  llvm::Constant *DeclPtr,
164  bool PerformInit) {
165 
166  const Expr *Init = D.getInit();
167  QualType T = D.getType();
168 
169  // The address space of a static local variable (DeclPtr) may be different
170  // from the address space of the "this" argument of the constructor. In that
171  // case, we need an addrspacecast before calling the constructor.
172  //
173  // struct StructWithCtor {
174  // __device__ StructWithCtor() {...}
175  // };
176  // __device__ void foo() {
177  // __shared__ StructWithCtor s;
178  // ...
179  // }
180  //
181  // For example, in the above CUDA code, the static local variable s has a
182  // "shared" address space qualifier, but the constructor of StructWithCtor
183  // expects "this" in the "generic" address space.
184  unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
185  unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
186  if (ActualAddrSpace != ExpectedAddrSpace) {
188  llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
189  DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
190  }
191 
192  ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
193 
194  if (!T->isReferenceType()) {
195  if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
196  D.hasAttr<OMPThreadPrivateDeclAttr>()) {
197  (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
198  &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
199  PerformInit, this);
200  }
201  if (PerformInit)
202  EmitDeclInit(*this, D, DeclAddr);
203  if (CGM.isTypeConstant(D.getType(), true))
204  EmitDeclInvariant(*this, D, DeclPtr);
205  else
206  EmitDeclDestroy(*this, D, DeclAddr);
207  return;
208  }
209 
210  assert(PerformInit && "cannot have constant initializer which needs "
211  "destruction for reference");
213  EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
214 }
215 
216 /// Create a stub function, suitable for being passed to atexit,
217 /// which passes the given address to the given destructor function.
218 llvm::Constant *CodeGenFunction::createAtExitStub(const VarDecl &VD,
219  llvm::Constant *dtor,
220  llvm::Constant *addr) {
221  // Get the destructor function type, void(*)(void).
222  llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
223  SmallString<256> FnName;
224  {
225  llvm::raw_svector_ostream Out(FnName);
227  }
228 
230  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
231  FI,
232  VD.getLocation());
233 
234  CodeGenFunction CGF(CGM);
235 
236  CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn, FI, FunctionArgList());
237 
238  llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
239 
240  // Make sure the call and the callee agree on calling convention.
241  if (llvm::Function *dtorFn =
242  dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
243  call->setCallingConv(dtorFn->getCallingConv());
244 
245  CGF.FinishFunction();
246 
247  return fn;
248 }
249 
250 /// Register a global destructor using the C atexit runtime function.
252  llvm::Constant *dtor,
253  llvm::Constant *addr) {
254  // Create a function which calls the destructor.
255  llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
257 }
258 
259 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
260  // extern "C" int atexit(void (*f)(void));
261  llvm::FunctionType *atexitTy =
262  llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
263 
264  llvm::Constant *atexit =
265  CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
266  /*Local=*/true);
267  if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
268  atexitFn->setDoesNotThrow();
269 
270  EmitNounwindRuntimeCall(atexit, dtorStub);
271 }
272 
274  llvm::GlobalVariable *DeclPtr,
275  bool PerformInit) {
276  // If we've been asked to forbid guard variables, emit an error now.
277  // This diagnostic is hard-coded for Darwin's use case; we can find
278  // better phrasing if someone else needs it.
279  if (CGM.getCodeGenOpts().ForbidGuardVariables)
280  CGM.Error(D.getLocation(),
281  "this initialization requires a guard variable, which "
282  "the kernel does not support");
283 
284  CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
285 }
286 
288  llvm::BasicBlock *InitBlock,
289  llvm::BasicBlock *NoInitBlock,
290  GuardKind Kind,
291  const VarDecl *D) {
292  assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
293 
294  // A guess at how many times we will enter the initialization of a
295  // variable, depending on the kind of variable.
296  static const uint64_t InitsPerTLSVar = 1024;
297  static const uint64_t InitsPerLocalVar = 1024 * 1024;
298 
299  llvm::MDNode *Weights;
300  if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
301  // For non-local variables, don't apply any weighting for now. Due to our
302  // use of COMDATs, we expect there to be at most one initialization of the
303  // variable per DSO, but we have no way to know how many DSOs will try to
304  // initialize the variable.
305  Weights = nullptr;
306  } else {
307  uint64_t NumInits;
308  // FIXME: For the TLS case, collect and use profiling information to
309  // determine a more accurate brach weight.
310  if (Kind == GuardKind::TlsGuard || D->getTLSKind())
311  NumInits = InitsPerTLSVar;
312  else
313  NumInits = InitsPerLocalVar;
314 
315  // The probability of us entering the initializer is
316  // 1 / (total number of times we attempt to initialize the variable).
317  llvm::MDBuilder MDHelper(CGM.getLLVMContext());
318  Weights = MDHelper.createBranchWeights(1, NumInits - 1);
319  }
320 
321  Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
322 }
323 
325  llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
326  SourceLocation Loc, bool TLS) {
327  llvm::Function *Fn =
329  Name, &getModule());
330  if (!getLangOpts().AppleKext && !TLS) {
331  // Set the section if needed.
332  if (const char *Section = getTarget().getStaticInitSectionSpecifier())
333  Fn->setSection(Section);
334  }
335 
336  SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
337 
338  Fn->setCallingConv(getRuntimeCC());
339 
340  if (!getLangOpts().Exceptions)
341  Fn->setDoesNotThrow();
342 
343  if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
344  !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
345  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
346 
347  if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
348  !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
349  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
350 
351  if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
352  !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
353  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
354 
355  if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
356  !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
357  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
358 
359  if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
360  !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
361  Fn->addFnAttr(llvm::Attribute::SanitizeThread);
362 
363  if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
364  !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
365  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
366 
367  if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
368  !isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
369  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
370 
371  if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
372  !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
373  Fn->addFnAttr(llvm::Attribute::SafeStack);
374 
375  if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
376  !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
377  Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
378 
379  auto RASignKind = getCodeGenOpts().getSignReturnAddress();
381  Fn->addFnAttr("sign-return-address",
383  ? "all"
384  : "non-leaf");
385  auto RASignKey = getCodeGenOpts().getSignReturnAddressKey();
386  Fn->addFnAttr("sign-return-address-key",
387  RASignKey == CodeGenOptions::SignReturnAddressKeyValue::AKey
388  ? "a_key"
389  : "b_key");
390  }
391 
392  if (getCodeGenOpts().BranchTargetEnforcement)
393  Fn->addFnAttr("branch-target-enforcement");
394 
395  return Fn;
396 }
397 
398 /// Create a global pointer to a function that will initialize a global
399 /// variable. The user has requested that this pointer be emitted in a specific
400 /// section.
401 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
402  llvm::GlobalVariable *GV,
403  llvm::Function *InitFunc,
404  InitSegAttr *ISA) {
405  llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
406  TheModule, InitFunc->getType(), /*isConstant=*/true,
407  llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
408  PtrArray->setSection(ISA->getSection());
409  addUsedGlobal(PtrArray);
410 
411  // If the GV is already in a comdat group, then we have to join it.
412  if (llvm::Comdat *C = GV->getComdat())
413  PtrArray->setComdat(C);
414 }
415 
416 void
417 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
418  llvm::GlobalVariable *Addr,
419  bool PerformInit) {
420 
421  // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
422  // __constant__ and __shared__ variables defined in namespace scope,
423  // that are of class type, cannot have a non-empty constructor. All
424  // the checks have been done in Sema by now. Whatever initializers
425  // are allowed are empty and we just need to ignore them here.
426  if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
427  (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
428  D->hasAttr<CUDASharedAttr>()))
429  return;
430 
431  if (getLangOpts().OpenMP &&
432  getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
433  return;
434 
435  // Check if we've already initialized this decl.
436  auto I = DelayedCXXInitPosition.find(D);
437  if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
438  return;
439 
440  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
441  SmallString<256> FnName;
442  {
443  llvm::raw_svector_ostream Out(FnName);
444  getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
445  }
446 
447  // Create a variable initialization function.
448  llvm::Function *Fn =
449  CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
451  D->getLocation());
452 
453  auto *ISA = D->getAttr<InitSegAttr>();
455  PerformInit);
456 
457  llvm::GlobalVariable *COMDATKey =
458  supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
459 
460  if (D->getTLSKind()) {
461  // FIXME: Should we support init_priority for thread_local?
462  // FIXME: We only need to register one __cxa_thread_atexit function for the
463  // entire TU.
464  CXXThreadLocalInits.push_back(Fn);
465  CXXThreadLocalInitVars.push_back(D);
466  } else if (PerformInit && ISA) {
467  EmitPointerToInitFunc(D, Addr, Fn, ISA);
468  } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
469  OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
470  PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
472  // C++ [basic.start.init]p2:
473  // Definitions of explicitly specialized class template static data
474  // members have ordered initialization. Other class template static data
475  // members (i.e., implicitly or explicitly instantiated specializations)
476  // have unordered initialization.
477  //
478  // As a consequence, we can put them into their own llvm.global_ctors entry.
479  //
480  // If the global is externally visible, put the initializer into a COMDAT
481  // group with the global being initialized. On most platforms, this is a
482  // minor startup time optimization. In the MS C++ ABI, there are no guard
483  // variables, so this COMDAT key is required for correctness.
484  AddGlobalCtor(Fn, 65535, COMDATKey);
485  } else if (D->hasAttr<SelectAnyAttr>()) {
486  // SelectAny globals will be comdat-folded. Put the initializer into a
487  // COMDAT group associated with the global, so the initializers get folded
488  // too.
489  AddGlobalCtor(Fn, 65535, COMDATKey);
490  } else {
491  I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
492  if (I == DelayedCXXInitPosition.end()) {
493  CXXGlobalInits.push_back(Fn);
494  } else if (I->second != ~0U) {
495  assert(I->second < CXXGlobalInits.size() &&
496  CXXGlobalInits[I->second] == nullptr);
497  CXXGlobalInits[I->second] = Fn;
498  }
499  }
500 
501  // Remember that we already emitted the initializer for this global.
502  DelayedCXXInitPosition[D] = ~0U;
503 }
504 
505 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
506  getCXXABI().EmitThreadLocalInitFuncs(
507  *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
508 
509  CXXThreadLocalInits.clear();
510  CXXThreadLocalInitVars.clear();
511  CXXThreadLocals.clear();
512 }
513 
514 void
515 CodeGenModule::EmitCXXGlobalInitFunc() {
516  while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
517  CXXGlobalInits.pop_back();
518 
519  if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
520  return;
521 
522  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
524 
525  // Create our global initialization function.
526  if (!PrioritizedCXXGlobalInits.empty()) {
527  SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
528  llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
529  PrioritizedCXXGlobalInits.end());
530  // Iterate over "chunks" of ctors with same priority and emit each chunk
531  // into separate function. Note - everything is sorted first by priority,
532  // second - by lex order, so we emit ctor functions in proper order.
534  I = PrioritizedCXXGlobalInits.begin(),
535  E = PrioritizedCXXGlobalInits.end(); I != E; ) {
537  PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
538 
539  LocalCXXGlobalInits.clear();
540  unsigned Priority = I->first.priority;
541  // Compute the function suffix from priority. Prepend with zeroes to make
542  // sure the function names are also ordered as priorities.
543  std::string PrioritySuffix = llvm::utostr(Priority);
544  // Priority is always <= 65535 (enforced by sema).
545  PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
546  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
547  FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
548 
549  for (; I < PrioE; ++I)
550  LocalCXXGlobalInits.push_back(I->second);
551 
552  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
553  AddGlobalCtor(Fn, Priority);
554  }
555  PrioritizedCXXGlobalInits.clear();
556  }
557 
558  // Include the filename in the symbol name. Including "sub_" matches gcc and
559  // makes sure these symbols appear lexicographically behind the symbols with
560  // priority emitted above.
561  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
562  if (FileName.empty())
563  FileName = "<null>";
564 
565  for (size_t i = 0; i < FileName.size(); ++i) {
566  // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
567  // to be the set of C preprocessing numbers.
568  if (!isPreprocessingNumberBody(FileName[i]))
569  FileName[i] = '_';
570  }
571 
572  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
573  FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
574 
575  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
576  AddGlobalCtor(Fn);
577 
578  CXXGlobalInits.clear();
579 }
580 
581 void CodeGenModule::EmitCXXGlobalDtorFunc() {
582  if (CXXGlobalDtors.empty())
583  return;
584 
585  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
586 
587  // Create our global destructor function.
589  llvm::Function *Fn =
590  CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
591 
592  CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
593  AddGlobalDtor(Fn);
594 }
595 
596 /// Emit the code necessary to initialize the given global variable.
598  const VarDecl *D,
599  llvm::GlobalVariable *Addr,
600  bool PerformInit) {
601  // Check if we need to emit debug info for variable initializer.
602  if (D->hasAttr<NoDebugAttr>())
603  DebugInfo = nullptr; // disable debug info indefinitely for this function
604 
605  CurEHLocation = D->getBeginLoc();
606 
608  getTypes().arrangeNullaryFunction(),
610  D->getInit()->getExprLoc());
611 
612  // Use guarded initialization if the global variable is weak. This
613  // occurs for, e.g., instantiated static data members and
614  // definitions explicitly marked weak.
615  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
616  EmitCXXGuardedInit(*D, Addr, PerformInit);
617  } else {
618  EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
619  }
620 
621  FinishFunction();
622 }
623 
624 void
627  ConstantAddress Guard) {
628  {
629  auto NL = ApplyDebugLocation::CreateEmpty(*this);
631  getTypes().arrangeNullaryFunction(), FunctionArgList());
632  // Emit an artificial location for this function.
633  auto AL = ApplyDebugLocation::CreateArtificial(*this);
634 
635  llvm::BasicBlock *ExitBlock = nullptr;
636  if (Guard.isValid()) {
637  // If we have a guard variable, check whether we've already performed
638  // these initializations. This happens for TLS initialization functions.
639  llvm::Value *GuardVal = Builder.CreateLoad(Guard);
640  llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
641  "guard.uninitialized");
642  llvm::BasicBlock *InitBlock = createBasicBlock("init");
643  ExitBlock = createBasicBlock("exit");
644  EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
645  GuardKind::TlsGuard, nullptr);
646  EmitBlock(InitBlock);
647  // Mark as initialized before initializing anything else. If the
648  // initializers use previously-initialized thread_local vars, that's
649  // probably supposed to be OK, but the standard doesn't say.
650  Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
651 
652  // The guard variable can't ever change again.
654  Guard.getPointer(),
656  CGM.getDataLayout().getTypeAllocSize(GuardVal->getType())));
657  }
658 
659  RunCleanupsScope Scope(*this);
660 
661  // When building in Objective-C++ ARC mode, create an autorelease pool
662  // around the global initializers.
663  if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
666  }
667 
668  for (unsigned i = 0, e = Decls.size(); i != e; ++i)
669  if (Decls[i])
670  EmitRuntimeCall(Decls[i]);
671 
672  Scope.ForceCleanup();
673 
674  if (ExitBlock) {
675  Builder.CreateBr(ExitBlock);
676  EmitBlock(ExitBlock);
677  }
678  }
679 
680  FinishFunction();
681 }
682 
684  llvm::Function *Fn,
685  const std::vector<std::pair<llvm::WeakTrackingVH, llvm::Constant *>>
686  &DtorsAndObjects) {
687  {
688  auto NL = ApplyDebugLocation::CreateEmpty(*this);
690  getTypes().arrangeNullaryFunction(), FunctionArgList());
691  // Emit an artificial location for this function.
692  auto AL = ApplyDebugLocation::CreateArtificial(*this);
693 
694  // Emit the dtors, in reverse order from construction.
695  for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
696  llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
697  llvm::CallInst *CI = Builder.CreateCall(Callee,
698  DtorsAndObjects[e - i - 1].second);
699  // Make sure the call and the callee agree on calling convention.
700  if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
701  CI->setCallingConv(F->getCallingConv());
702  }
703  }
704 
705  FinishFunction();
706 }
707 
708 /// generateDestroyHelper - Generates a helper function which, when
709 /// invoked, destroys the given object. The address of the object
710 /// should be in global memory.
712  Address addr, QualType type, Destroyer *destroyer,
713  bool useEHCleanupForArray, const VarDecl *VD) {
714  FunctionArgList args;
717  args.push_back(&Dst);
718 
719  const CGFunctionInfo &FI =
721  llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
722  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
723  FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
724 
725  CurEHLocation = VD->getBeginLoc();
726 
727  StartFunction(VD, getContext().VoidTy, fn, FI, args);
728 
729  emitDestroy(addr, type, destroyer, useEHCleanupForArray);
730 
731  FinishFunction();
732 
733  return fn;
734 }
const CGFunctionInfo & arrangeBuiltinFunctionDeclaration(QualType resultType, const FunctionArgList &args)
A builtin function is a freestanding function using the default C conventions.
Definition: CGCall.cpp:659
const llvm::DataLayout & getDataLayout() const
void EmitCXXGuardedInitBranch(llvm::Value *NeedsInit, llvm::BasicBlock *InitBlock, llvm::BasicBlock *NoInitBlock, GuardKind Kind, const VarDecl *D)
Emit a branch to select whether or not to perform guarded initialization.
Definition: CGDeclCXX.cpp:287
llvm::IntegerType * IntTy
int
Other implicit parameter.
Definition: Decl.h:1511
Destroyer * getDestroyer(QualType::DestructionKind destructionKind)
Definition: CGDecl.cpp:1684
A (possibly-)qualified type.
Definition: Type.h:638
const CodeGenOptions & getCodeGenOpts() const
llvm::LLVMContext & getLLVMContext()
The base class of the type hierarchy.
Definition: Type.h:1411
void EmitComplexExprIntoLValue(const Expr *E, LValue dest, bool isInit)
EmitComplexExprIntoLValue - Emit the given expression of complex type and place its result into the s...
Represents a variable declaration or definition.
Definition: Decl.h:812
llvm::Value * EmitObjCAutoreleasePoolPush()
Produce the code to do a objc_autoreleasepool_push.
Definition: CGObjC.cpp:2387
llvm::Type * ConvertTypeForMem(QualType T)
ConvertTypeForMem - Convert type T into a llvm::Type.
std::string getName(ArrayRef< StringRef > Parts) const
Get the platform-specific name separator.
const TargetInfo & getTarget() const
void emitDestroy(Address addr, QualType type, Destroyer *destroyer, bool useEHCleanupForArray)
emitDestroy - Immediately perform the destruction of the given object.
Definition: CGDecl.cpp:1759
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
llvm::Type * ConvertType(QualType T)
ConvertType - Convert type T into a llvm::Type.
RValue EmitReferenceBindingToExpr(const Expr *E)
Emits a reference binding to the passed in expression.
Definition: CGExpr.cpp:589
llvm::Constant * getAddrOfCXXStructor(const CXXMethodDecl *MD, StructorType Type, const CGFunctionInfo *FnInfo=nullptr, llvm::FunctionType *FnType=nullptr, bool DontDefer=false, ForDefinition_t IsForDefinition=NotForDefinition)
Return the address of the constructor/destructor of the given type.
Definition: CGCXX.cpp:231
llvm::CallInst * EmitRuntimeCall(llvm::Value *callee, const Twine &name="")
bool isReferenceType() const
Definition: Type.h:6312
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Decl.h:738
void GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn, const VarDecl *D, llvm::GlobalVariable *Addr, bool PerformInit)
Emit the code necessary to initialize the given global variable.
Definition: CGDeclCXX.cpp:597
void EmitStoreOfScalar(llvm::Value *Value, Address Addr, bool Volatile, QualType Ty, AlignmentSource Source=AlignmentSource::Type, bool isInit=false, bool isNontemporal=false)
EmitStoreOfScalar - Store a scalar value to an address, taking care to appropriately convert from the...
static ApplyDebugLocation CreateArtificial(CodeGenFunction &CGF)
Apply TemporaryLocation if it is valid.
Definition: CGDebugInfo.h:715
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
TemplateSpecializationKind getTemplateSpecializationKind() const
If this variable is an instantiation of a variable template or a static data member of a class templa...
Definition: Decl.cpp:2434
bool needsEHCleanup(QualType::DestructionKind kind)
Determines whether an EH cleanup is required to destroy a type with the given destruction kind...
void registerGlobalDtorWithAtExit(const VarDecl &D, llvm::Constant *fn, llvm::Constant *addr)
Call atexit() with a function that passes the given argument to the given function.
Definition: CGDeclCXX.cpp:251
bool isObjCWeak() const
Definition: CGValue.h:294
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
llvm::BasicBlock * createBasicBlock(const Twine &name="", llvm::Function *parent=nullptr, llvm::BasicBlock *before=nullptr)
createBasicBlock - Create an LLVM basic block.
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1478
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1697
virtual bool canCallMismatchedFunctionType() const
Returns true if the target allows calling a function through a pointer with a different signature tha...
Definition: CGCXXABI.h:119
constexpr XRayInstrMask All
Definition: XRayInstr.h:42
llvm::Constant * CreateRuntimeFunction(llvm::FunctionType *Ty, StringRef Name, llvm::AttributeList ExtraAttrs=llvm::AttributeList(), bool Local=false)
Create a new runtime function with the specified type and name.
virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF, llvm::Value *src, Address dest, bool threadlocal=false)=0
bool isTypeConstant(QualType QTy, bool ExcludeCtorDtor)
isTypeConstant - Determine whether an object of this type can be emitted as a constant.
bool hasAttr() const
Definition: DeclBase.h:531
bool isValid() const
Definition: Address.h:36
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1613
llvm::CallInst * EmitNounwindRuntimeCall(llvm::Value *callee, const Twine &name="")
RValue - This trivial value class is used to represent the result of an expression that is evaluated...
Definition: CGValue.h:39
virtual void mangleDynamicAtExitDestructor(const VarDecl *D, raw_ostream &)=0
QuantityType getQuantity() const
getQuantity - Get the raw integer representation of this quantity.
Definition: CharUnits.h:179
virtual bool HasThisReturn(GlobalDecl GD) const
Returns true if the given constructor or destructor is one of the kinds that the ABI says returns &#39;th...
Definition: CGCXXABI.h:107
llvm::CallingConv::ID getRuntimeCC() const
void EmitCXXGuardedInit(const VarDecl &D, llvm::GlobalVariable *DeclPtr, bool PerformInit)
Emit code in this function to perform a guarded variable initialization.
Definition: CGDeclCXX.cpp:273
CGObjCRuntime & getObjCRuntime()
Return a reference to the configured Objective-C runtime.
static TypeEvaluationKind getEvaluationKind(QualType T)
getEvaluationKind - Return the TypeEvaluationKind of QualType T.
llvm::Function * generateDestroyHelper(Address addr, QualType type, Destroyer *destroyer, bool useEHCleanupForArray, const VarDecl *VD)
generateDestroyHelper - Generates a helper function which, when invoked, destroys the given object...
Definition: CGDeclCXX.cpp:711
This represents one expression.
Definition: Expr.h:106
bool hasLocalStorage() const
Returns true if a variable with function scope is a non-static local variable.
Definition: Decl.h:1035
Enters a new scope for capturing cleanups, all of which will be executed once the scope is exited...
const CGFunctionInfo & arrangeNullaryFunction()
A nullary function is a freestanding function of type &#39;void ()&#39;.
Definition: CGCall.cpp:701
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2706
virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, llvm::GlobalVariable *DeclPtr, bool PerformInit)=0
Emits the guarded initializer and destructor setup for the given variable, given that it couldn&#39;t be ...
void EmitInvariantStart(llvm::Constant *Addr, CharUnits Size)
Definition: CGDeclCXX.cpp:144
TLSKind getTLSKind() const
Definition: Decl.cpp:1936
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:63
virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, llvm::Constant *Dtor, llvm::Constant *Addr)=0
Emit code to force the execution of a destructor during global teardown.
void GenerateCXXGlobalInitFunc(llvm::Function *Fn, ArrayRef< llvm::Function *> CXXThreadLocals, ConstantAddress Guard=ConstantAddress::invalid())
GenerateCXXGlobalInitFunc - Generates code for initializing global variables.
Definition: CGDeclCXX.cpp:625
void EmitCXXGlobalVarDeclInit(const VarDecl &D, llvm::Constant *DeclPtr, bool PerformInit)
EmitCXXGlobalVarDeclInit - Create the initializer for a C++ variable with global storage.
Definition: CGDeclCXX.cpp:162
bool isObjCStrong() const
Definition: CGValue.h:297
ASTContext & getContext() const
bool isTemplateInstantiation(TemplateSpecializationKind Kind)
Determine whether this template specialization kind refers to an instantiation of an entity (as oppos...
Definition: Specifiers.h:170
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:35
The l-value was considered opaque, so the alignment was determined from a type.
Kind
Encodes a location in the source.
llvm::Constant * createAtExitStub(const VarDecl &VD, llvm::Constant *Dtor, llvm::Constant *Addr)
Create a stub function, suitable for being passed to atexit, which passes the given address to the gi...
Definition: CGDeclCXX.cpp:218
bool hasGlobalStorage() const
Returns true for all variables that do not have local storage.
Definition: Decl.h:1077
CanQualType VoidTy
Definition: ASTContext.h:1015
An aligned address.
Definition: Address.h:25
void StartFunction(GlobalDecl GD, QualType RetTy, llvm::Function *Fn, const CGFunctionInfo &FnInfo, const FunctionArgList &Args, SourceLocation Loc=SourceLocation(), SourceLocation StartLoc=SourceLocation())
Emit code for the start of a function.
DestructionKind isDestructedType() const
Returns a nonzero value if objects of this type require non-trivial work to clean up after...
Definition: Type.h:1156
MangleContext & getMangleContext()
Gets the mangle context.
Definition: CGCXXABI.h:97
Complete object dtor.
Definition: ABI.h:36
constexpr XRayInstrMask None
Definition: XRayInstr.h:38
void Error(SourceLocation loc, StringRef error)
Emit a general error that something can&#39;t be done.
void FinishFunction(SourceLocation EndLoc=SourceLocation())
FinishFunction - Complete IR generation of the current function.
SourceLocation getExprLoc() const LLVM_READONLY
getExprLoc - Return the preferred location for the arrow when diagnosing a problem with a generic exp...
Definition: Expr.cpp:215
llvm::Value * EmitScalarExpr(const Expr *E, bool IgnoreResultAssign=false)
EmitScalarExpr - Emit the computation of the specified expression of LLVM scalar type, returning the result.
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:356
llvm::Value * getScalarVal() const
getScalarVal() - Return the Value* of this scalar value.
Definition: CGValue.h:59
CGFunctionInfo - Class to encapsulate the information about a function definition.
This class organizes the cross-function state that is used while generating LLVM code.
CGOpenMPRuntime & getOpenMPRuntime()
Return a reference to the configured OpenMP runtime.
Dataflow Directional Tag Classes.
const Expr * getInit() const
Definition: Decl.h:1219
llvm::Constant * getPointer() const
Definition: Address.h:84
llvm::LoadInst * CreateLoad(Address Addr, const llvm::Twine &Name="")
Definition: CGBuilder.h:70
static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D, ConstantAddress Addr)
Emit code to cause the destruction of the given variable with static storage duration.
Definition: CGDeclCXX.cpp:68
llvm::Function * getIntrinsic(unsigned IID, ArrayRef< llvm::Type *> Tys=None)
llvm::StoreInst * CreateStore(llvm::Value *Val, Address Addr, bool IsVolatile=false)
Definition: CGBuilder.h:108
static AggValueSlot forLValue(const LValue &LV, IsDestructed_t isDestructed, NeedsGCBarriers_t needsGC, IsAliased_t isAliased, Overlap_t mayOverlap, IsZeroed_t isZeroed=IsNotZeroed, IsSanitizerChecked_t isChecked=IsNotSanitizerChecked)
Definition: CGValue.h:540
LValue MakeAddrLValue(Address Addr, QualType T, AlignmentSource Source=AlignmentSource::Type)
void EmitAggExpr(const Expr *E, AggValueSlot AS)
EmitAggExpr - Emit the computation of the specified expression of aggregate type. ...
Definition: CGExprAgg.cpp:1777
virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF, llvm::Value *src, Address dest)=0
virtual bool emitDeclareTargetVarDefinition(const VarDecl *VD, llvm::GlobalVariable *Addr, bool PerformInit)
Emit a code for initialization of declare target variable.
CodeGenTypes & getTypes() const
T * getAttr() const
Definition: DeclBase.h:527
void EmitScalarInit(const Expr *init, const ValueDecl *D, LValue lvalue, bool capturedByInit)
Definition: CGDecl.cpp:740
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:32
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:443
static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D, ConstantAddress DeclPtr)
Definition: CGDeclCXX.cpp:27
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
llvm::Function * CreateGlobalInitOrDestructFunction(llvm::FunctionType *ty, const Twine &name, const CGFunctionInfo &FI, SourceLocation Loc=SourceLocation(), bool TLS=false)
Definition: CGDeclCXX.cpp:324
A specialization of Address that requires the address to be an LLVM Constant.
Definition: Address.h:75
CGCXXABI & getCXXABI() const
void EmitObjCAutoreleasePoolCleanup(llvm::Value *Ptr)
Definition: CGObjC.cpp:2518
void GenerateCXXGlobalDtorsFunc(llvm::Function *Fn, const std::vector< std::pair< llvm::WeakTrackingVH, llvm::Constant *>> &DtorsAndObjects)
GenerateCXXGlobalDtorsFunc - Generates code for destroying global variables.
Definition: CGDeclCXX.cpp:683
CharUnits getTypeSizeInChars(QualType T) const
Return the size of the specified (complete) type T, in characters.
static ApplyDebugLocation CreateEmpty(CodeGenFunction &CGF)
Set the IRBuilder to not attach debug locations.
Definition: CGDebugInfo.h:732
bool isLocalVarDecl() const
Returns true for local variable declarations other than parameters.
Definition: Decl.h:1104
QualType getType() const
Definition: Decl.h:647
LValue - This represents an lvalue references.
Definition: CGValue.h:167
const LangOptions & getLangOpts() const
unsigned getTargetAddressSpace(QualType T) const
Definition: ASTContext.h:2498
LLVM_READONLY bool isPreprocessingNumberBody(unsigned char c)
Return true if this is the body character of a C preprocessing number, which is [a-zA-Z0-9_.
Definition: CharInfo.h:148
const LangOptions & getLangOpts() const
Definition: ASTContext.h:706
SourceLocation getLocation() const
Definition: DeclBase.h:418
bool isExternallyVisible() const
Definition: Decl.h:379
static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D, llvm::Constant *Addr)
Emit code to cause the variable at the given address to be considered as constant from this point onw...
Definition: CGDeclCXX.cpp:138
static OMPLinearClause * Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc, OpenMPLinearClauseKind Modifier, SourceLocation ModifierLoc, SourceLocation ColonLoc, SourceLocation EndLoc, ArrayRef< Expr *> VL, ArrayRef< Expr *> PL, ArrayRef< Expr *> IL, Expr *Step, Expr *CalcStep, Stmt *PreInit, Expr *PostUpdate)
Creates clause with a list of variables VL and a linear step Step.
void Destroyer(CodeGenFunction &CGF, Address addr, QualType ty)
static CharUnits getDeclAlign(Expr *E, CharUnits TypeAlign, ASTContext &Context)
A helper function to get the alignment of a Decl referred to by DeclRefExpr or MemberExpr.
llvm::FunctionType * GetFunctionType(const CGFunctionInfo &Info)
GetFunctionType - Get the LLVM function type for.
Definition: CGCall.cpp:1550
bool isNoDestroy(const ASTContext &) const
Do we need to emit an exit-time destructor for this variable?
Definition: Decl.cpp:2480