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(D.hasGlobalStorage() && "VarDecl must have global storage!");
30  assert(!D.getType()->isReferenceType() &&
31  "Should not call EmitDeclInit on a reference!");
32 
33  QualType type = D.getType();
34  LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
35 
36  const Expr *Init = D.getInit();
37  switch (CGF.getEvaluationKind(type)) {
38  case TEK_Scalar: {
39  CodeGenModule &CGM = CGF.CGM;
40  if (lv.isObjCStrong())
42  DeclPtr, D.getTLSKind());
43  else if (lv.isObjCWeak())
45  DeclPtr);
46  else
47  CGF.EmitScalarInit(Init, &D, lv, false);
48  return;
49  }
50  case TEK_Complex:
51  CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
52  return;
53  case TEK_Aggregate:
58  return;
59  }
60  llvm_unreachable("bad evaluation kind");
61 }
62 
63 /// Emit code to cause the destruction of the given variable with
64 /// static storage duration.
65 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
66  ConstantAddress Addr) {
67  // Honor __attribute__((no_destroy)) and bail instead of attempting
68  // to emit a reference to a possibly nonexistent destructor, which
69  // in turn can cause a crash. This will result in a global constructor
70  // that isn't balanced out by a destructor call as intended by the
71  // attribute. This also checks for -fno-c++-static-destructors and
72  // bails even if the attribute is not present.
73  if (D.isNoDestroy(CGF.getContext()))
74  return;
75 
76  CodeGenModule &CGM = CGF.CGM;
77 
78  // FIXME: __attribute__((cleanup)) ?
79 
80  QualType Type = D.getType();
82 
83  switch (DtorKind) {
84  case QualType::DK_none:
85  return;
86 
88  break;
89 
93  // We don't care about releasing objects during process teardown.
94  assert(!D.getTLSKind() && "should have rejected this");
95  return;
96  }
97 
98  llvm::Constant *Func;
99  llvm::Constant *Argument;
100 
101  // Special-case non-array C++ destructors, if they have the right signature.
102  // Under some ABIs, destructors return this instead of void, and cannot be
103  // passed directly to __cxa_atexit if the target does not allow this
104  // mismatch.
105  const CXXRecordDecl *Record = Type->getAsCXXRecordDecl();
106  bool CanRegisterDestructor =
107  Record && (!CGM.getCXXABI().HasThisReturn(
108  GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
110  // If __cxa_atexit is disabled via a flag, a different helper function is
111  // generated elsewhere which uses atexit instead, and it takes the destructor
112  // directly.
113  bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
114  if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
115  assert(!Record->hasTrivialDestructor());
116  CXXDestructorDecl *Dtor = Record->getDestructor();
117 
119  Argument = llvm::ConstantExpr::getBitCast(
120  Addr.getPointer(), CGF.getTypes().ConvertType(Type)->getPointerTo());
121 
122  // Otherwise, the standard logic requires a helper function.
123  } else {
124  Func = CodeGenFunction(CGM)
125  .generateDestroyHelper(Addr, Type, CGF.getDestroyer(DtorKind),
126  CGF.needsEHCleanup(DtorKind), &D);
127  Argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
128  }
129 
130  CGM.getCXXABI().registerGlobalDtor(CGF, D, Func, Argument);
131 }
132 
133 /// Emit code to cause the variable at the given address to be considered as
134 /// constant from this point onwards.
135 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
136  llvm::Constant *Addr) {
137  return CGF.EmitInvariantStart(
138  Addr, CGF.getContext().getTypeSizeInChars(D.getType()));
139 }
140 
141 void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
142  // Do not emit the intrinsic if we're not optimizing.
143  if (!CGM.getCodeGenOpts().OptimizationLevel)
144  return;
145 
146  // Grab the llvm.invariant.start intrinsic.
147  llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
148  // Overloaded address space type.
149  llvm::Type *ObjectPtr[1] = {Int8PtrTy};
150  llvm::Constant *InvariantStart = CGM.getIntrinsic(InvStartID, ObjectPtr);
151 
152  // Emit a call with the size in bytes of the object.
153  uint64_t Width = Size.getQuantity();
154  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
155  llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
156  Builder.CreateCall(InvariantStart, Args);
157 }
158 
160  llvm::Constant *DeclPtr,
161  bool PerformInit) {
162 
163  const Expr *Init = D.getInit();
164  QualType T = D.getType();
165 
166  // The address space of a static local variable (DeclPtr) may be different
167  // from the address space of the "this" argument of the constructor. In that
168  // case, we need an addrspacecast before calling the constructor.
169  //
170  // struct StructWithCtor {
171  // __device__ StructWithCtor() {...}
172  // };
173  // __device__ void foo() {
174  // __shared__ StructWithCtor s;
175  // ...
176  // }
177  //
178  // For example, in the above CUDA code, the static local variable s has a
179  // "shared" address space qualifier, but the constructor of StructWithCtor
180  // expects "this" in the "generic" address space.
181  unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
182  unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
183  if (ActualAddrSpace != ExpectedAddrSpace) {
185  llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
186  DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
187  }
188 
189  ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
190 
191  if (!T->isReferenceType()) {
192  if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
193  D.hasAttr<OMPThreadPrivateDeclAttr>()) {
194  (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
195  &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
196  PerformInit, this);
197  }
198  if (PerformInit)
199  EmitDeclInit(*this, D, DeclAddr);
200  if (CGM.isTypeConstant(D.getType(), true))
201  EmitDeclInvariant(*this, D, DeclPtr);
202  else
203  EmitDeclDestroy(*this, D, DeclAddr);
204  return;
205  }
206 
207  assert(PerformInit && "cannot have constant initializer which needs "
208  "destruction for reference");
210  EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
211 }
212 
213 /// Create a stub function, suitable for being passed to atexit,
214 /// which passes the given address to the given destructor function.
215 llvm::Constant *CodeGenFunction::createAtExitStub(const VarDecl &VD,
216  llvm::Constant *dtor,
217  llvm::Constant *addr) {
218  // Get the destructor function type, void(*)(void).
219  llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
220  SmallString<256> FnName;
221  {
222  llvm::raw_svector_ostream Out(FnName);
224  }
225 
227  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
228  FI,
229  VD.getLocation());
230 
231  CodeGenFunction CGF(CGM);
232 
233  CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn, FI, FunctionArgList());
234 
235  llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
236 
237  // Make sure the call and the callee agree on calling convention.
238  if (llvm::Function *dtorFn =
239  dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
240  call->setCallingConv(dtorFn->getCallingConv());
241 
242  CGF.FinishFunction();
243 
244  return fn;
245 }
246 
247 /// Register a global destructor using the C atexit runtime function.
249  llvm::Constant *dtor,
250  llvm::Constant *addr) {
251  // Create a function which calls the destructor.
252  llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
254 }
255 
256 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
257  // extern "C" int atexit(void (*f)(void));
258  llvm::FunctionType *atexitTy =
259  llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
260 
261  llvm::Constant *atexit =
262  CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
263  /*Local=*/true);
264  if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
265  atexitFn->setDoesNotThrow();
266 
267  EmitNounwindRuntimeCall(atexit, dtorStub);
268 }
269 
271  llvm::GlobalVariable *DeclPtr,
272  bool PerformInit) {
273  // If we've been asked to forbid guard variables, emit an error now.
274  // This diagnostic is hard-coded for Darwin's use case; we can find
275  // better phrasing if someone else needs it.
276  if (CGM.getCodeGenOpts().ForbidGuardVariables)
277  CGM.Error(D.getLocation(),
278  "this initialization requires a guard variable, which "
279  "the kernel does not support");
280 
281  CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
282 }
283 
285  llvm::BasicBlock *InitBlock,
286  llvm::BasicBlock *NoInitBlock,
287  GuardKind Kind,
288  const VarDecl *D) {
289  assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
290 
291  // A guess at how many times we will enter the initialization of a
292  // variable, depending on the kind of variable.
293  static const uint64_t InitsPerTLSVar = 1024;
294  static const uint64_t InitsPerLocalVar = 1024 * 1024;
295 
296  llvm::MDNode *Weights;
297  if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
298  // For non-local variables, don't apply any weighting for now. Due to our
299  // use of COMDATs, we expect there to be at most one initialization of the
300  // variable per DSO, but we have no way to know how many DSOs will try to
301  // initialize the variable.
302  Weights = nullptr;
303  } else {
304  uint64_t NumInits;
305  // FIXME: For the TLS case, collect and use profiling information to
306  // determine a more accurate brach weight.
307  if (Kind == GuardKind::TlsGuard || D->getTLSKind())
308  NumInits = InitsPerTLSVar;
309  else
310  NumInits = InitsPerLocalVar;
311 
312  // The probability of us entering the initializer is
313  // 1 / (total number of times we attempt to initialize the variable).
314  llvm::MDBuilder MDHelper(CGM.getLLVMContext());
315  Weights = MDHelper.createBranchWeights(1, NumInits - 1);
316  }
317 
318  Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
319 }
320 
322  llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
323  SourceLocation Loc, bool TLS) {
324  llvm::Function *Fn =
326  Name, &getModule());
327  if (!getLangOpts().AppleKext && !TLS) {
328  // Set the section if needed.
329  if (const char *Section = getTarget().getStaticInitSectionSpecifier())
330  Fn->setSection(Section);
331  }
332 
333  SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
334 
335  Fn->setCallingConv(getRuntimeCC());
336 
337  if (!getLangOpts().Exceptions)
338  Fn->setDoesNotThrow();
339 
340  if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
341  !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
342  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
343 
344  if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
345  !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
346  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
347 
348  if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
349  !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
350  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
351 
352  if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
353  !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
354  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
355 
356  if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
357  !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
358  Fn->addFnAttr(llvm::Attribute::SanitizeThread);
359 
360  if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
361  !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
362  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
363 
364  if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
365  !isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
366  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
367 
368  if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
369  !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
370  Fn->addFnAttr(llvm::Attribute::SafeStack);
371 
372  if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
373  !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
374  Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
375 
376  auto RASignKind = getCodeGenOpts().getSignReturnAddress();
378  Fn->addFnAttr("sign-return-address",
380  ? "all"
381  : "non-leaf");
382  auto RASignKey = getCodeGenOpts().getSignReturnAddressKey();
383  Fn->addFnAttr("sign-return-address-key",
384  RASignKey == CodeGenOptions::SignReturnAddressKeyValue::AKey
385  ? "a_key"
386  : "b_key");
387  }
388 
389  if (getCodeGenOpts().BranchTargetEnforcement)
390  Fn->addFnAttr("branch-target-enforcement");
391 
392  return Fn;
393 }
394 
395 /// Create a global pointer to a function that will initialize a global
396 /// variable. The user has requested that this pointer be emitted in a specific
397 /// section.
398 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
399  llvm::GlobalVariable *GV,
400  llvm::Function *InitFunc,
401  InitSegAttr *ISA) {
402  llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
403  TheModule, InitFunc->getType(), /*isConstant=*/true,
404  llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
405  PtrArray->setSection(ISA->getSection());
406  addUsedGlobal(PtrArray);
407 
408  // If the GV is already in a comdat group, then we have to join it.
409  if (llvm::Comdat *C = GV->getComdat())
410  PtrArray->setComdat(C);
411 }
412 
413 void
414 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
415  llvm::GlobalVariable *Addr,
416  bool PerformInit) {
417 
418  // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
419  // __constant__ and __shared__ variables defined in namespace scope,
420  // that are of class type, cannot have a non-empty constructor. All
421  // the checks have been done in Sema by now. Whatever initializers
422  // are allowed are empty and we just need to ignore them here.
423  if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
424  (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
425  D->hasAttr<CUDASharedAttr>()))
426  return;
427 
428  if (getLangOpts().OpenMP &&
429  getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
430  return;
431 
432  // Check if we've already initialized this decl.
433  auto I = DelayedCXXInitPosition.find(D);
434  if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
435  return;
436 
437  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
438  SmallString<256> FnName;
439  {
440  llvm::raw_svector_ostream Out(FnName);
441  getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
442  }
443 
444  // Create a variable initialization function.
445  llvm::Function *Fn =
446  CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
448  D->getLocation());
449 
450  auto *ISA = D->getAttr<InitSegAttr>();
452  PerformInit);
453 
454  llvm::GlobalVariable *COMDATKey =
455  supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
456 
457  if (D->getTLSKind()) {
458  // FIXME: Should we support init_priority for thread_local?
459  // FIXME: We only need to register one __cxa_thread_atexit function for the
460  // entire TU.
461  CXXThreadLocalInits.push_back(Fn);
462  CXXThreadLocalInitVars.push_back(D);
463  } else if (PerformInit && ISA) {
464  EmitPointerToInitFunc(D, Addr, Fn, ISA);
465  } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
466  OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
467  PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
469  // C++ [basic.start.init]p2:
470  // Definitions of explicitly specialized class template static data
471  // members have ordered initialization. Other class template static data
472  // members (i.e., implicitly or explicitly instantiated specializations)
473  // have unordered initialization.
474  //
475  // As a consequence, we can put them into their own llvm.global_ctors entry.
476  //
477  // If the global is externally visible, put the initializer into a COMDAT
478  // group with the global being initialized. On most platforms, this is a
479  // minor startup time optimization. In the MS C++ ABI, there are no guard
480  // variables, so this COMDAT key is required for correctness.
481  AddGlobalCtor(Fn, 65535, COMDATKey);
482  } else if (D->hasAttr<SelectAnyAttr>()) {
483  // SelectAny globals will be comdat-folded. Put the initializer into a
484  // COMDAT group associated with the global, so the initializers get folded
485  // too.
486  AddGlobalCtor(Fn, 65535, COMDATKey);
487  } else {
488  I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
489  if (I == DelayedCXXInitPosition.end()) {
490  CXXGlobalInits.push_back(Fn);
491  } else if (I->second != ~0U) {
492  assert(I->second < CXXGlobalInits.size() &&
493  CXXGlobalInits[I->second] == nullptr);
494  CXXGlobalInits[I->second] = Fn;
495  }
496  }
497 
498  // Remember that we already emitted the initializer for this global.
499  DelayedCXXInitPosition[D] = ~0U;
500 }
501 
502 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
503  getCXXABI().EmitThreadLocalInitFuncs(
504  *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
505 
506  CXXThreadLocalInits.clear();
507  CXXThreadLocalInitVars.clear();
508  CXXThreadLocals.clear();
509 }
510 
511 void
512 CodeGenModule::EmitCXXGlobalInitFunc() {
513  while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
514  CXXGlobalInits.pop_back();
515 
516  if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
517  return;
518 
519  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
521 
522  // Create our global initialization function.
523  if (!PrioritizedCXXGlobalInits.empty()) {
524  SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
525  llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
526  PrioritizedCXXGlobalInits.end());
527  // Iterate over "chunks" of ctors with same priority and emit each chunk
528  // into separate function. Note - everything is sorted first by priority,
529  // second - by lex order, so we emit ctor functions in proper order.
531  I = PrioritizedCXXGlobalInits.begin(),
532  E = PrioritizedCXXGlobalInits.end(); I != E; ) {
534  PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
535 
536  LocalCXXGlobalInits.clear();
537  unsigned Priority = I->first.priority;
538  // Compute the function suffix from priority. Prepend with zeroes to make
539  // sure the function names are also ordered as priorities.
540  std::string PrioritySuffix = llvm::utostr(Priority);
541  // Priority is always <= 65535 (enforced by sema).
542  PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
543  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
544  FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
545 
546  for (; I < PrioE; ++I)
547  LocalCXXGlobalInits.push_back(I->second);
548 
549  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
550  AddGlobalCtor(Fn, Priority);
551  }
552  PrioritizedCXXGlobalInits.clear();
553  }
554 
555  // Include the filename in the symbol name. Including "sub_" matches gcc and
556  // makes sure these symbols appear lexicographically behind the symbols with
557  // priority emitted above.
558  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
559  if (FileName.empty())
560  FileName = "<null>";
561 
562  for (size_t i = 0; i < FileName.size(); ++i) {
563  // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
564  // to be the set of C preprocessing numbers.
565  if (!isPreprocessingNumberBody(FileName[i]))
566  FileName[i] = '_';
567  }
568 
569  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
570  FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
571 
572  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
573  AddGlobalCtor(Fn);
574 
575  CXXGlobalInits.clear();
576 }
577 
578 void CodeGenModule::EmitCXXGlobalDtorFunc() {
579  if (CXXGlobalDtors.empty())
580  return;
581 
582  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
583 
584  // Create our global destructor function.
586  llvm::Function *Fn =
587  CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
588 
589  CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
590  AddGlobalDtor(Fn);
591 }
592 
593 /// Emit the code necessary to initialize the given global variable.
595  const VarDecl *D,
596  llvm::GlobalVariable *Addr,
597  bool PerformInit) {
598  // Check if we need to emit debug info for variable initializer.
599  if (D->hasAttr<NoDebugAttr>())
600  DebugInfo = nullptr; // disable debug info indefinitely for this function
601 
602  CurEHLocation = D->getBeginLoc();
603 
605  getTypes().arrangeNullaryFunction(),
607  D->getInit()->getExprLoc());
608 
609  // Use guarded initialization if the global variable is weak. This
610  // occurs for, e.g., instantiated static data members and
611  // definitions explicitly marked weak.
612  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
613  EmitCXXGuardedInit(*D, Addr, PerformInit);
614  } else {
615  EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
616  }
617 
618  FinishFunction();
619 }
620 
621 void
624  ConstantAddress Guard) {
625  {
626  auto NL = ApplyDebugLocation::CreateEmpty(*this);
628  getTypes().arrangeNullaryFunction(), FunctionArgList());
629  // Emit an artificial location for this function.
630  auto AL = ApplyDebugLocation::CreateArtificial(*this);
631 
632  llvm::BasicBlock *ExitBlock = nullptr;
633  if (Guard.isValid()) {
634  // If we have a guard variable, check whether we've already performed
635  // these initializations. This happens for TLS initialization functions.
636  llvm::Value *GuardVal = Builder.CreateLoad(Guard);
637  llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
638  "guard.uninitialized");
639  llvm::BasicBlock *InitBlock = createBasicBlock("init");
640  ExitBlock = createBasicBlock("exit");
641  EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
642  GuardKind::TlsGuard, nullptr);
643  EmitBlock(InitBlock);
644  // Mark as initialized before initializing anything else. If the
645  // initializers use previously-initialized thread_local vars, that's
646  // probably supposed to be OK, but the standard doesn't say.
647  Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
648 
649  // The guard variable can't ever change again.
651  Guard.getPointer(),
653  CGM.getDataLayout().getTypeAllocSize(GuardVal->getType())));
654  }
655 
656  RunCleanupsScope Scope(*this);
657 
658  // When building in Objective-C++ ARC mode, create an autorelease pool
659  // around the global initializers.
660  if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
663  }
664 
665  for (unsigned i = 0, e = Decls.size(); i != e; ++i)
666  if (Decls[i])
667  EmitRuntimeCall(Decls[i]);
668 
669  Scope.ForceCleanup();
670 
671  if (ExitBlock) {
672  Builder.CreateBr(ExitBlock);
673  EmitBlock(ExitBlock);
674  }
675  }
676 
677  FinishFunction();
678 }
679 
681  llvm::Function *Fn,
682  const std::vector<std::pair<llvm::WeakTrackingVH, llvm::Constant *>>
683  &DtorsAndObjects) {
684  {
685  auto NL = ApplyDebugLocation::CreateEmpty(*this);
687  getTypes().arrangeNullaryFunction(), FunctionArgList());
688  // Emit an artificial location for this function.
689  auto AL = ApplyDebugLocation::CreateArtificial(*this);
690 
691  // Emit the dtors, in reverse order from construction.
692  for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
693  llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
694  llvm::CallInst *CI = Builder.CreateCall(Callee,
695  DtorsAndObjects[e - i - 1].second);
696  // Make sure the call and the callee agree on calling convention.
697  if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
698  CI->setCallingConv(F->getCallingConv());
699  }
700  }
701 
702  FinishFunction();
703 }
704 
705 /// generateDestroyHelper - Generates a helper function which, when
706 /// invoked, destroys the given object. The address of the object
707 /// should be in global memory.
709  Address addr, QualType type, Destroyer *destroyer,
710  bool useEHCleanupForArray, const VarDecl *VD) {
711  FunctionArgList args;
714  args.push_back(&Dst);
715 
716  const CGFunctionInfo &FI =
718  llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
719  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
720  FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
721 
722  CurEHLocation = VD->getBeginLoc();
723 
724  StartFunction(VD, getContext().VoidTy, fn, FI, args);
725 
726  emitDestroy(addr, type, destroyer, useEHCleanupForArray);
727 
728  FinishFunction();
729 
730  return fn;
731 }
const CGFunctionInfo & arrangeBuiltinFunctionDeclaration(QualType resultType, const FunctionArgList &args)
A builtin function is a freestanding function using the default C conventions.
Definition: CGCall.cpp:657
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:284
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:642
const CodeGenOptions & getCodeGenOpts() const
llvm::LLVMContext & getLLVMContext()
The base class of the type hierarchy.
Definition: Type.h:1415
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:6294
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:594
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:711
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:248
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:270
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:708
This represents one expression.
Definition: Expr.h:106
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:699
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2703
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:141
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:622
void EmitCXXGlobalVarDeclInit(const VarDecl &D, llvm::Constant *DeclPtr, bool PerformInit)
EmitCXXGlobalVarDeclInit - Create the initializer for a C++ variable with global storage.
Definition: CGDeclCXX.cpp:159
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:215
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:1160
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:216
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:65
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:321
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:680
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:728
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
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:135
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:1548
bool isNoDestroy(const ASTContext &) const
Do we need to emit an exit-time destructor for this variable?
Definition: Decl.cpp:2480