clang  7.0.0svn
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:
57  return;
58  }
59  llvm_unreachable("bad evaluation kind");
60 }
61 
62 /// Emit code to cause the destruction of the given variable with
63 /// static storage duration.
64 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
65  ConstantAddress addr) {
66  CodeGenModule &CGM = CGF.CGM;
67 
68  // FIXME: __attribute__((cleanup)) ?
69 
70  QualType type = D.getType();
72 
73  switch (dtorKind) {
74  case QualType::DK_none:
75  return;
76 
78  break;
79 
82  // We don't care about releasing objects during process teardown.
83  assert(!D.getTLSKind() && "should have rejected this");
84  return;
85  }
86 
87  llvm::Constant *function;
88  llvm::Constant *argument;
89 
90  // Special-case non-array C++ destructors, if they have the right signature.
91  // Under some ABIs, destructors return this instead of void, and cannot be
92  // passed directly to __cxa_atexit if the target does not allow this mismatch.
93  const CXXRecordDecl *Record = type->getAsCXXRecordDecl();
94  bool CanRegisterDestructor =
95  Record && (!CGM.getCXXABI().HasThisReturn(
96  GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
98  // If __cxa_atexit is disabled via a flag, a different helper function is
99  // generated elsewhere which uses atexit instead, and it takes the destructor
100  // directly.
101  bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
102  if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
103  assert(!Record->hasTrivialDestructor());
104  CXXDestructorDecl *dtor = Record->getDestructor();
105 
106  function = CGM.getAddrOfCXXStructor(dtor, StructorType::Complete);
107  argument = llvm::ConstantExpr::getBitCast(
108  addr.getPointer(), CGF.getTypes().ConvertType(type)->getPointerTo());
109 
110  // Otherwise, the standard logic requires a helper function.
111  } else {
112  function = CodeGenFunction(CGM)
113  .generateDestroyHelper(addr, type, CGF.getDestroyer(dtorKind),
114  CGF.needsEHCleanup(dtorKind), &D);
115  argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
116  }
117 
118  CGM.getCXXABI().registerGlobalDtor(CGF, D, function, argument);
119 }
120 
121 /// Emit code to cause the variable at the given address to be considered as
122 /// constant from this point onwards.
123 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
124  llvm::Constant *Addr) {
125  // Do not emit the intrinsic if we're not optimizing.
126  if (!CGF.CGM.getCodeGenOpts().OptimizationLevel)
127  return;
128 
129  // Grab the llvm.invariant.start intrinsic.
130  llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
131  // Overloaded address space type.
132  llvm::Type *ObjectPtr[1] = {CGF.Int8PtrTy};
133  llvm::Constant *InvariantStart = CGF.CGM.getIntrinsic(InvStartID, ObjectPtr);
134 
135  // Emit a call with the size in bytes of the object.
136  CharUnits WidthChars = CGF.getContext().getTypeSizeInChars(D.getType());
137  uint64_t Width = WidthChars.getQuantity();
138  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, Width),
139  llvm::ConstantExpr::getBitCast(Addr, CGF.Int8PtrTy)};
140  CGF.Builder.CreateCall(InvariantStart, Args);
141 }
142 
144  llvm::Constant *DeclPtr,
145  bool PerformInit) {
146 
147  const Expr *Init = D.getInit();
148  QualType T = D.getType();
149 
150  // The address space of a static local variable (DeclPtr) may be different
151  // from the address space of the "this" argument of the constructor. In that
152  // case, we need an addrspacecast before calling the constructor.
153  //
154  // struct StructWithCtor {
155  // __device__ StructWithCtor() {...}
156  // };
157  // __device__ void foo() {
158  // __shared__ StructWithCtor s;
159  // ...
160  // }
161  //
162  // For example, in the above CUDA code, the static local variable s has a
163  // "shared" address space qualifier, but the constructor of StructWithCtor
164  // expects "this" in the "generic" address space.
165  unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
166  unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
167  if (ActualAddrSpace != ExpectedAddrSpace) {
169  llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
170  DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
171  }
172 
173  ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
174 
175  if (!T->isReferenceType()) {
176  if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
177  D.hasAttr<OMPThreadPrivateDeclAttr>()) {
178  (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
179  &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
180  PerformInit, this);
181  }
182  if (PerformInit)
183  EmitDeclInit(*this, D, DeclAddr);
184  if (CGM.isTypeConstant(D.getType(), true))
185  EmitDeclInvariant(*this, D, DeclPtr);
186  else
187  EmitDeclDestroy(*this, D, DeclAddr);
188  return;
189  }
190 
191  assert(PerformInit && "cannot have constant initializer which needs "
192  "destruction for reference");
194  EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
195 }
196 
197 /// Create a stub function, suitable for being passed to atexit,
198 /// which passes the given address to the given destructor function.
199 llvm::Constant *CodeGenFunction::createAtExitStub(const VarDecl &VD,
200  llvm::Constant *dtor,
201  llvm::Constant *addr) {
202  // Get the destructor function type, void(*)(void).
203  llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
204  SmallString<256> FnName;
205  {
206  llvm::raw_svector_ostream Out(FnName);
208  }
209 
211  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
212  FI,
213  VD.getLocation());
214 
215  CodeGenFunction CGF(CGM);
216 
217  CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn, FI, FunctionArgList());
218 
219  llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
220 
221  // Make sure the call and the callee agree on calling convention.
222  if (llvm::Function *dtorFn =
223  dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
224  call->setCallingConv(dtorFn->getCallingConv());
225 
226  CGF.FinishFunction();
227 
228  return fn;
229 }
230 
231 /// Register a global destructor using the C atexit runtime function.
233  llvm::Constant *dtor,
234  llvm::Constant *addr) {
235  // Create a function which calls the destructor.
236  llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
237 
238  // extern "C" int atexit(void (*f)(void));
239  llvm::FunctionType *atexitTy =
240  llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
241 
242  llvm::Constant *atexit =
243  CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
244  /*Local=*/true);
245  if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
246  atexitFn->setDoesNotThrow();
247 
248  EmitNounwindRuntimeCall(atexit, dtorStub);
249 }
250 
252  llvm::GlobalVariable *DeclPtr,
253  bool PerformInit) {
254  // If we've been asked to forbid guard variables, emit an error now.
255  // This diagnostic is hard-coded for Darwin's use case; we can find
256  // better phrasing if someone else needs it.
257  if (CGM.getCodeGenOpts().ForbidGuardVariables)
258  CGM.Error(D.getLocation(),
259  "this initialization requires a guard variable, which "
260  "the kernel does not support");
261 
262  CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
263 }
264 
266  llvm::BasicBlock *InitBlock,
267  llvm::BasicBlock *NoInitBlock,
268  GuardKind Kind,
269  const VarDecl *D) {
270  assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
271 
272  // A guess at how many times we will enter the initialization of a
273  // variable, depending on the kind of variable.
274  static const uint64_t InitsPerTLSVar = 1024;
275  static const uint64_t InitsPerLocalVar = 1024 * 1024;
276 
277  llvm::MDNode *Weights;
278  if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
279  // For non-local variables, don't apply any weighting for now. Due to our
280  // use of COMDATs, we expect there to be at most one initialization of the
281  // variable per DSO, but we have no way to know how many DSOs will try to
282  // initialize the variable.
283  Weights = nullptr;
284  } else {
285  uint64_t NumInits;
286  // FIXME: For the TLS case, collect and use profiling information to
287  // determine a more accurate brach weight.
288  if (Kind == GuardKind::TlsGuard || D->getTLSKind())
289  NumInits = InitsPerTLSVar;
290  else
291  NumInits = InitsPerLocalVar;
292 
293  // The probability of us entering the initializer is
294  // 1 / (total number of times we attempt to initialize the variable).
295  llvm::MDBuilder MDHelper(CGM.getLLVMContext());
296  Weights = MDHelper.createBranchWeights(1, NumInits - 1);
297  }
298 
299  Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
300 }
301 
303  llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
304  SourceLocation Loc, bool TLS) {
305  llvm::Function *Fn =
307  Name, &getModule());
308  if (!getLangOpts().AppleKext && !TLS) {
309  // Set the section if needed.
310  if (const char *Section = getTarget().getStaticInitSectionSpecifier())
311  Fn->setSection(Section);
312  }
313 
314  SetInternalFunctionAttributes(nullptr, Fn, FI);
315 
316  Fn->setCallingConv(getRuntimeCC());
317 
318  if (!getLangOpts().Exceptions)
319  Fn->setDoesNotThrow();
320 
321  if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
322  !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
323  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
324 
325  if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
326  !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
327  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
328 
329  if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
330  !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
331  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
332 
333  if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
334  !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
335  Fn->addFnAttr(llvm::Attribute::SanitizeThread);
336 
337  if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
338  !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
339  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
340 
341  if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
342  !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
343  Fn->addFnAttr(llvm::Attribute::SafeStack);
344 
345  return Fn;
346 }
347 
348 /// Create a global pointer to a function that will initialize a global
349 /// variable. The user has requested that this pointer be emitted in a specific
350 /// section.
351 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
352  llvm::GlobalVariable *GV,
353  llvm::Function *InitFunc,
354  InitSegAttr *ISA) {
355  llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
356  TheModule, InitFunc->getType(), /*isConstant=*/true,
357  llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
358  PtrArray->setSection(ISA->getSection());
359  addUsedGlobal(PtrArray);
360 
361  // If the GV is already in a comdat group, then we have to join it.
362  if (llvm::Comdat *C = GV->getComdat())
363  PtrArray->setComdat(C);
364 }
365 
366 void
367 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
368  llvm::GlobalVariable *Addr,
369  bool PerformInit) {
370 
371  // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
372  // __constant__ and __shared__ variables defined in namespace scope,
373  // that are of class type, cannot have a non-empty constructor. All
374  // the checks have been done in Sema by now. Whatever initializers
375  // are allowed are empty and we just need to ignore them here.
376  if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
377  (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
378  D->hasAttr<CUDASharedAttr>()))
379  return;
380 
381  // Check if we've already initialized this decl.
382  auto I = DelayedCXXInitPosition.find(D);
383  if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
384  return;
385 
386  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
387  SmallString<256> FnName;
388  {
389  llvm::raw_svector_ostream Out(FnName);
390  getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
391  }
392 
393  // Create a variable initialization function.
394  llvm::Function *Fn =
395  CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
397  D->getLocation());
398 
399  auto *ISA = D->getAttr<InitSegAttr>();
401  PerformInit);
402 
403  llvm::GlobalVariable *COMDATKey =
404  supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
405 
406  if (D->getTLSKind()) {
407  // FIXME: Should we support init_priority for thread_local?
408  // FIXME: We only need to register one __cxa_thread_atexit function for the
409  // entire TU.
410  CXXThreadLocalInits.push_back(Fn);
411  CXXThreadLocalInitVars.push_back(D);
412  } else if (PerformInit && ISA) {
413  EmitPointerToInitFunc(D, Addr, Fn, ISA);
414  } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
415  OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
416  PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
418  // C++ [basic.start.init]p2:
419  // Definitions of explicitly specialized class template static data
420  // members have ordered initialization. Other class template static data
421  // members (i.e., implicitly or explicitly instantiated specializations)
422  // have unordered initialization.
423  //
424  // As a consequence, we can put them into their own llvm.global_ctors entry.
425  //
426  // If the global is externally visible, put the initializer into a COMDAT
427  // group with the global being initialized. On most platforms, this is a
428  // minor startup time optimization. In the MS C++ ABI, there are no guard
429  // variables, so this COMDAT key is required for correctness.
430  AddGlobalCtor(Fn, 65535, COMDATKey);
431  } else if (D->hasAttr<SelectAnyAttr>()) {
432  // SelectAny globals will be comdat-folded. Put the initializer into a
433  // COMDAT group associated with the global, so the initializers get folded
434  // too.
435  AddGlobalCtor(Fn, 65535, COMDATKey);
436  } else {
437  I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
438  if (I == DelayedCXXInitPosition.end()) {
439  CXXGlobalInits.push_back(Fn);
440  } else if (I->second != ~0U) {
441  assert(I->second < CXXGlobalInits.size() &&
442  CXXGlobalInits[I->second] == nullptr);
443  CXXGlobalInits[I->second] = Fn;
444  }
445  }
446 
447  // Remember that we already emitted the initializer for this global.
448  DelayedCXXInitPosition[D] = ~0U;
449 }
450 
451 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
452  getCXXABI().EmitThreadLocalInitFuncs(
453  *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
454 
455  CXXThreadLocalInits.clear();
456  CXXThreadLocalInitVars.clear();
457  CXXThreadLocals.clear();
458 }
459 
460 void
461 CodeGenModule::EmitCXXGlobalInitFunc() {
462  while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
463  CXXGlobalInits.pop_back();
464 
465  if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
466  return;
467 
468  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
470 
471  // Create our global initialization function.
472  if (!PrioritizedCXXGlobalInits.empty()) {
473  SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
474  llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
475  PrioritizedCXXGlobalInits.end());
476  // Iterate over "chunks" of ctors with same priority and emit each chunk
477  // into separate function. Note - everything is sorted first by priority,
478  // second - by lex order, so we emit ctor functions in proper order.
480  I = PrioritizedCXXGlobalInits.begin(),
481  E = PrioritizedCXXGlobalInits.end(); I != E; ) {
483  PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
484 
485  LocalCXXGlobalInits.clear();
486  unsigned Priority = I->first.priority;
487  // Compute the function suffix from priority. Prepend with zeroes to make
488  // sure the function names are also ordered as priorities.
489  std::string PrioritySuffix = llvm::utostr(Priority);
490  // Priority is always <= 65535 (enforced by sema).
491  PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
492  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
493  FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
494 
495  for (; I < PrioE; ++I)
496  LocalCXXGlobalInits.push_back(I->second);
497 
498  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
499  AddGlobalCtor(Fn, Priority);
500  }
501  PrioritizedCXXGlobalInits.clear();
502  }
503 
504  // Include the filename in the symbol name. Including "sub_" matches gcc and
505  // makes sure these symbols appear lexicographically behind the symbols with
506  // priority emitted above.
507  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
508  if (FileName.empty())
509  FileName = "<null>";
510 
511  for (size_t i = 0; i < FileName.size(); ++i) {
512  // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
513  // to be the set of C preprocessing numbers.
514  if (!isPreprocessingNumberBody(FileName[i]))
515  FileName[i] = '_';
516  }
517 
518  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
519  FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
520 
521  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
522  AddGlobalCtor(Fn);
523 
524  CXXGlobalInits.clear();
525 }
526 
527 void CodeGenModule::EmitCXXGlobalDtorFunc() {
528  if (CXXGlobalDtors.empty())
529  return;
530 
531  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
532 
533  // Create our global destructor function.
535  llvm::Function *Fn =
536  CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
537 
538  CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
539  AddGlobalDtor(Fn);
540 }
541 
542 /// Emit the code necessary to initialize the given global variable.
544  const VarDecl *D,
545  llvm::GlobalVariable *Addr,
546  bool PerformInit) {
547  // Check if we need to emit debug info for variable initializer.
548  if (D->hasAttr<NoDebugAttr>())
549  DebugInfo = nullptr; // disable debug info indefinitely for this function
550 
551  CurEHLocation = D->getLocStart();
552 
554  getTypes().arrangeNullaryFunction(),
556  D->getInit()->getExprLoc());
557 
558  // Use guarded initialization if the global variable is weak. This
559  // occurs for, e.g., instantiated static data members and
560  // definitions explicitly marked weak.
561  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
562  EmitCXXGuardedInit(*D, Addr, PerformInit);
563  } else {
564  EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
565  }
566 
567  FinishFunction();
568 }
569 
570 void
573  Address Guard) {
574  {
575  auto NL = ApplyDebugLocation::CreateEmpty(*this);
577  getTypes().arrangeNullaryFunction(), FunctionArgList());
578  // Emit an artificial location for this function.
579  auto AL = ApplyDebugLocation::CreateArtificial(*this);
580 
581  llvm::BasicBlock *ExitBlock = nullptr;
582  if (Guard.isValid()) {
583  // If we have a guard variable, check whether we've already performed
584  // these initializations. This happens for TLS initialization functions.
585  llvm::Value *GuardVal = Builder.CreateLoad(Guard);
586  llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
587  "guard.uninitialized");
588  llvm::BasicBlock *InitBlock = createBasicBlock("init");
589  ExitBlock = createBasicBlock("exit");
590  EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
591  GuardKind::TlsGuard, nullptr);
592  EmitBlock(InitBlock);
593  // Mark as initialized before initializing anything else. If the
594  // initializers use previously-initialized thread_local vars, that's
595  // probably supposed to be OK, but the standard doesn't say.
596  Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
597  }
598 
599  RunCleanupsScope Scope(*this);
600 
601  // When building in Objective-C++ ARC mode, create an autorelease pool
602  // around the global initializers.
603  if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
606  }
607 
608  for (unsigned i = 0, e = Decls.size(); i != e; ++i)
609  if (Decls[i])
610  EmitRuntimeCall(Decls[i]);
611 
612  Scope.ForceCleanup();
613 
614  if (ExitBlock) {
615  Builder.CreateBr(ExitBlock);
616  EmitBlock(ExitBlock);
617  }
618  }
619 
620  FinishFunction();
621 }
622 
624  llvm::Function *Fn,
625  const std::vector<std::pair<llvm::WeakTrackingVH, llvm::Constant *>>
626  &DtorsAndObjects) {
627  {
628  auto NL = ApplyDebugLocation::CreateEmpty(*this);
630  getTypes().arrangeNullaryFunction(), FunctionArgList());
631  // Emit an artificial location for this function.
632  auto AL = ApplyDebugLocation::CreateArtificial(*this);
633 
634  // Emit the dtors, in reverse order from construction.
635  for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
636  llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
637  llvm::CallInst *CI = Builder.CreateCall(Callee,
638  DtorsAndObjects[e - i - 1].second);
639  // Make sure the call and the callee agree on calling convention.
640  if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
641  CI->setCallingConv(F->getCallingConv());
642  }
643  }
644 
645  FinishFunction();
646 }
647 
648 /// generateDestroyHelper - Generates a helper function which, when
649 /// invoked, destroys the given object. The address of the object
650 /// should be in global memory.
652  Address addr, QualType type, Destroyer *destroyer,
653  bool useEHCleanupForArray, const VarDecl *VD) {
654  FunctionArgList args;
657  args.push_back(&Dst);
658 
659  const CGFunctionInfo &FI =
661  llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
662  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
663  FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
664 
665  CurEHLocation = VD->getLocStart();
666 
667  StartFunction(VD, getContext().VoidTy, fn, FI, args);
668 
669  emitDestroy(addr, type, destroyer, useEHCleanupForArray);
670 
671  FinishFunction();
672 
673  return fn;
674 }
const CGFunctionInfo & arrangeBuiltinFunctionDeclaration(QualType resultType, const FunctionArgList &args)
A builtin function is a freestanding function using the default C conventions.
Definition: CGCall.cpp:640
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:265
llvm::IntegerType * IntTy
int
Other implicit parameter.
Definition: Decl.h:1475
Destroyer * getDestroyer(QualType::DestructionKind destructionKind)
Definition: CGDecl.cpp:1519
A (possibly-)qualified type.
Definition: Type.h:653
const CodeGenOptions & getCodeGenOpts() const
llvm::LLVMContext & getLLVMContext()
static AggValueSlot forLValue(const LValue &LV, IsDestructed_t isDestructed, NeedsGCBarriers_t needsGC, IsAliased_t isAliased, IsZeroed_t isZeroed=IsNotZeroed)
Definition: CGValue.h:517
void GenerateCXXGlobalInitFunc(llvm::Function *Fn, ArrayRef< llvm::Function *> CXXThreadLocals, Address Guard=Address::invalid())
GenerateCXXGlobalInitFunc - Generates code for initializing global variables.
Definition: CGDeclCXX.cpp:571
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:2312
llvm::Type * ConvertTypeForMem(QualType T)
ConvertTypeForMem - Convert type T into a llvm::Type.
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:64
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:1595
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:531
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:238
llvm::CallInst * EmitRuntimeCall(llvm::Value *callee, const Twine &name="")
bool isReferenceType() const
Definition: Type.h:5960
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:543
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:668
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:2378
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:232
bool isObjCWeak() const
Definition: CGValue.h:291
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.
void ForceCleanup(std::initializer_list< llvm::Value **> ValuesToReload={})
Force the emission of cleanups now, instead of waiting until this object is destroyed.
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1437
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1515
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
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:535
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:1590
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:251
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:651
Expr - 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 FunctionProtoType * T
const CGFunctionInfo & arrangeNullaryFunction()
A nullary function is a freestanding function of type &#39;void ()&#39;.
Definition: CGCall.cpp:682
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2675
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 ...
TLSKind getTLSKind() const
Definition: Decl.cpp:1888
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 EmitCXXGlobalVarDeclInit(const VarDecl &D, llvm::Constant *DeclPtr, bool PerformInit)
EmitCXXGlobalVarDeclInit - Create the initializer for a C++ variable with global storage.
Definition: CGDeclCXX.cpp:143
bool isObjCStrong() const
Definition: CGValue.h:294
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:167
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:199
bool hasGlobalStorage() const
Returns true for all variables that do not have local storage.
Definition: Decl.h:1072
CanQualType VoidTy
Definition: ASTContext.h:996
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:1101
MangleContext & getMangleContext()
Gets the mangle context.
Definition: CGCXXABI.h:97
Complete object dtor.
Definition: ABI.h:36
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:320
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:1214
llvm::Constant * getPointer() const
Definition: Address.h:84
llvm::LoadInst * CreateLoad(Address Addr, const llvm::Twine &Name="")
Definition: CGBuilder.h:70
SourceLocation getLocStart() const LLVM_READONLY
Definition: Decl.h:738
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
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:1548
virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF, llvm::Value *src, Address dest)=0
CodeGenTypes & getTypes() const
T * getAttr() const
Definition: DeclBase.h:531
void EmitScalarInit(const Expr *init, const ValueDecl *D, LValue lvalue, bool capturedByInit)
Definition: CGDecl.cpp:715
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:33
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:445
static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D, ConstantAddress DeclPtr)
Definition: CGDeclCXX.cpp:27
Represents a C++ struct/union/class.
Definition: DeclCXX.h:299
llvm::Function * CreateGlobalInitOrDestructFunction(llvm::FunctionType *ty, const Twine &name, const CGFunctionInfo &FI, SourceLocation Loc=SourceLocation(), bool TLS=false)
Definition: CGDeclCXX.cpp:302
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:2425
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:623
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:685
bool isLocalVarDecl() const
Returns true for local variable declarations other than parameters.
Definition: Decl.h:1099
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:2418
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:416
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:123
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:1524