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  CodeGenModule &CGM = CGF.CGM;
68 
69  // FIXME: __attribute__((cleanup)) ?
70 
71  QualType type = D.getType();
73 
74  switch (dtorKind) {
75  case QualType::DK_none:
76  return;
77 
79  break;
80 
84  // We don't care about releasing objects during process teardown.
85  assert(!D.getTLSKind() && "should have rejected this");
86  return;
87  }
88 
89  llvm::Constant *function;
90  llvm::Constant *argument;
91 
92  // Special-case non-array C++ destructors, if they have the right signature.
93  // Under some ABIs, destructors return this instead of void, and cannot be
94  // passed directly to __cxa_atexit if the target does not allow this mismatch.
95  const CXXRecordDecl *Record = type->getAsCXXRecordDecl();
96  bool CanRegisterDestructor =
97  Record && (!CGM.getCXXABI().HasThisReturn(
98  GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
100  // If __cxa_atexit is disabled via a flag, a different helper function is
101  // generated elsewhere which uses atexit instead, and it takes the destructor
102  // directly.
103  bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
104  if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
105  assert(!Record->hasTrivialDestructor());
106  CXXDestructorDecl *dtor = Record->getDestructor();
107 
108  function = CGM.getAddrOfCXXStructor(dtor, StructorType::Complete);
109  argument = llvm::ConstantExpr::getBitCast(
110  addr.getPointer(), CGF.getTypes().ConvertType(type)->getPointerTo());
111 
112  // Otherwise, the standard logic requires a helper function.
113  } else {
114  function = CodeGenFunction(CGM)
115  .generateDestroyHelper(addr, type, CGF.getDestroyer(dtorKind),
116  CGF.needsEHCleanup(dtorKind), &D);
117  argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
118  }
119 
120  CGM.getCXXABI().registerGlobalDtor(CGF, D, function, argument);
121 }
122 
123 /// Emit code to cause the variable at the given address to be considered as
124 /// constant from this point onwards.
125 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
126  llvm::Constant *Addr) {
127  // Do not emit the intrinsic if we're not optimizing.
128  if (!CGF.CGM.getCodeGenOpts().OptimizationLevel)
129  return;
130 
131  // Grab the llvm.invariant.start intrinsic.
132  llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
133  // Overloaded address space type.
134  llvm::Type *ObjectPtr[1] = {CGF.Int8PtrTy};
135  llvm::Constant *InvariantStart = CGF.CGM.getIntrinsic(InvStartID, ObjectPtr);
136 
137  // Emit a call with the size in bytes of the object.
138  CharUnits WidthChars = CGF.getContext().getTypeSizeInChars(D.getType());
139  uint64_t Width = WidthChars.getQuantity();
140  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, Width),
141  llvm::ConstantExpr::getBitCast(Addr, CGF.Int8PtrTy)};
142  CGF.Builder.CreateCall(InvariantStart, Args);
143 }
144 
146  llvm::Constant *DeclPtr,
147  bool PerformInit) {
148 
149  const Expr *Init = D.getInit();
150  QualType T = D.getType();
151 
152  // The address space of a static local variable (DeclPtr) may be different
153  // from the address space of the "this" argument of the constructor. In that
154  // case, we need an addrspacecast before calling the constructor.
155  //
156  // struct StructWithCtor {
157  // __device__ StructWithCtor() {...}
158  // };
159  // __device__ void foo() {
160  // __shared__ StructWithCtor s;
161  // ...
162  // }
163  //
164  // For example, in the above CUDA code, the static local variable s has a
165  // "shared" address space qualifier, but the constructor of StructWithCtor
166  // expects "this" in the "generic" address space.
167  unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
168  unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
169  if (ActualAddrSpace != ExpectedAddrSpace) {
171  llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
172  DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
173  }
174 
175  ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
176 
177  if (!T->isReferenceType()) {
178  if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
179  D.hasAttr<OMPThreadPrivateDeclAttr>()) {
180  (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
181  &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
182  PerformInit, this);
183  }
184  if (PerformInit)
185  EmitDeclInit(*this, D, DeclAddr);
186  if (CGM.isTypeConstant(D.getType(), true))
187  EmitDeclInvariant(*this, D, DeclPtr);
188  else
189  EmitDeclDestroy(*this, D, DeclAddr);
190  return;
191  }
192 
193  assert(PerformInit && "cannot have constant initializer which needs "
194  "destruction for reference");
196  EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
197 }
198 
199 /// Create a stub function, suitable for being passed to atexit,
200 /// which passes the given address to the given destructor function.
201 llvm::Constant *CodeGenFunction::createAtExitStub(const VarDecl &VD,
202  llvm::Constant *dtor,
203  llvm::Constant *addr) {
204  // Get the destructor function type, void(*)(void).
205  llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
206  SmallString<256> FnName;
207  {
208  llvm::raw_svector_ostream Out(FnName);
210  }
211 
213  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
214  FI,
215  VD.getLocation());
216 
217  CodeGenFunction CGF(CGM);
218 
219  CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn, FI, FunctionArgList());
220 
221  llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
222 
223  // Make sure the call and the callee agree on calling convention.
224  if (llvm::Function *dtorFn =
225  dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
226  call->setCallingConv(dtorFn->getCallingConv());
227 
228  CGF.FinishFunction();
229 
230  return fn;
231 }
232 
233 /// Register a global destructor using the C atexit runtime function.
235  llvm::Constant *dtor,
236  llvm::Constant *addr) {
237  // Create a function which calls the destructor.
238  llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
240 }
241 
242 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
243  // extern "C" int atexit(void (*f)(void));
244  llvm::FunctionType *atexitTy =
245  llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
246 
247  llvm::Constant *atexit =
248  CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
249  /*Local=*/true);
250  if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
251  atexitFn->setDoesNotThrow();
252 
253  EmitNounwindRuntimeCall(atexit, dtorStub);
254 }
255 
257  llvm::GlobalVariable *DeclPtr,
258  bool PerformInit) {
259  // If we've been asked to forbid guard variables, emit an error now.
260  // This diagnostic is hard-coded for Darwin's use case; we can find
261  // better phrasing if someone else needs it.
262  if (CGM.getCodeGenOpts().ForbidGuardVariables)
263  CGM.Error(D.getLocation(),
264  "this initialization requires a guard variable, which "
265  "the kernel does not support");
266 
267  CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
268 }
269 
271  llvm::BasicBlock *InitBlock,
272  llvm::BasicBlock *NoInitBlock,
273  GuardKind Kind,
274  const VarDecl *D) {
275  assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
276 
277  // A guess at how many times we will enter the initialization of a
278  // variable, depending on the kind of variable.
279  static const uint64_t InitsPerTLSVar = 1024;
280  static const uint64_t InitsPerLocalVar = 1024 * 1024;
281 
282  llvm::MDNode *Weights;
283  if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
284  // For non-local variables, don't apply any weighting for now. Due to our
285  // use of COMDATs, we expect there to be at most one initialization of the
286  // variable per DSO, but we have no way to know how many DSOs will try to
287  // initialize the variable.
288  Weights = nullptr;
289  } else {
290  uint64_t NumInits;
291  // FIXME: For the TLS case, collect and use profiling information to
292  // determine a more accurate brach weight.
293  if (Kind == GuardKind::TlsGuard || D->getTLSKind())
294  NumInits = InitsPerTLSVar;
295  else
296  NumInits = InitsPerLocalVar;
297 
298  // The probability of us entering the initializer is
299  // 1 / (total number of times we attempt to initialize the variable).
300  llvm::MDBuilder MDHelper(CGM.getLLVMContext());
301  Weights = MDHelper.createBranchWeights(1, NumInits - 1);
302  }
303 
304  Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
305 }
306 
308  llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
309  SourceLocation Loc, bool TLS) {
310  llvm::Function *Fn =
312  Name, &getModule());
313  if (!getLangOpts().AppleKext && !TLS) {
314  // Set the section if needed.
315  if (const char *Section = getTarget().getStaticInitSectionSpecifier())
316  Fn->setSection(Section);
317  }
318 
319  SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
320 
321  Fn->setCallingConv(getRuntimeCC());
322 
323  if (!getLangOpts().Exceptions)
324  Fn->setDoesNotThrow();
325 
326  if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
327  !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
328  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
329 
330  if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
331  !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
332  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
333 
334  if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
335  !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
336  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
337 
338  if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
339  !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
340  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
341 
342  if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
343  !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
344  Fn->addFnAttr(llvm::Attribute::SanitizeThread);
345 
346  if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
347  !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
348  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
349 
350  if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
351  !isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
352  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
353 
354  if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
355  !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
356  Fn->addFnAttr(llvm::Attribute::SafeStack);
357 
358  if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
359  !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
360  Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
361 
362  auto RASignKind = getCodeGenOpts().getSignReturnAddress();
363  if (RASignKind != CodeGenOptions::SignReturnAddressScope::None)
364  Fn->addFnAttr("sign-return-address",
366  ? "all"
367  : "non-leaf");
368  return Fn;
369 }
370 
371 /// Create a global pointer to a function that will initialize a global
372 /// variable. The user has requested that this pointer be emitted in a specific
373 /// section.
374 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
375  llvm::GlobalVariable *GV,
376  llvm::Function *InitFunc,
377  InitSegAttr *ISA) {
378  llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
379  TheModule, InitFunc->getType(), /*isConstant=*/true,
380  llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
381  PtrArray->setSection(ISA->getSection());
382  addUsedGlobal(PtrArray);
383 
384  // If the GV is already in a comdat group, then we have to join it.
385  if (llvm::Comdat *C = GV->getComdat())
386  PtrArray->setComdat(C);
387 }
388 
389 void
390 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
391  llvm::GlobalVariable *Addr,
392  bool PerformInit) {
393 
394  // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
395  // __constant__ and __shared__ variables defined in namespace scope,
396  // that are of class type, cannot have a non-empty constructor. All
397  // the checks have been done in Sema by now. Whatever initializers
398  // are allowed are empty and we just need to ignore them here.
399  if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
400  (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
401  D->hasAttr<CUDASharedAttr>()))
402  return;
403 
404  if (getLangOpts().OpenMP &&
405  getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
406  return;
407 
408  // Check if we've already initialized this decl.
409  auto I = DelayedCXXInitPosition.find(D);
410  if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
411  return;
412 
413  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
414  SmallString<256> FnName;
415  {
416  llvm::raw_svector_ostream Out(FnName);
417  getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
418  }
419 
420  // Create a variable initialization function.
421  llvm::Function *Fn =
422  CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
424  D->getLocation());
425 
426  auto *ISA = D->getAttr<InitSegAttr>();
428  PerformInit);
429 
430  llvm::GlobalVariable *COMDATKey =
431  supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
432 
433  if (D->getTLSKind()) {
434  // FIXME: Should we support init_priority for thread_local?
435  // FIXME: We only need to register one __cxa_thread_atexit function for the
436  // entire TU.
437  CXXThreadLocalInits.push_back(Fn);
438  CXXThreadLocalInitVars.push_back(D);
439  } else if (PerformInit && ISA) {
440  EmitPointerToInitFunc(D, Addr, Fn, ISA);
441  } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
442  OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
443  PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
445  // C++ [basic.start.init]p2:
446  // Definitions of explicitly specialized class template static data
447  // members have ordered initialization. Other class template static data
448  // members (i.e., implicitly or explicitly instantiated specializations)
449  // have unordered initialization.
450  //
451  // As a consequence, we can put them into their own llvm.global_ctors entry.
452  //
453  // If the global is externally visible, put the initializer into a COMDAT
454  // group with the global being initialized. On most platforms, this is a
455  // minor startup time optimization. In the MS C++ ABI, there are no guard
456  // variables, so this COMDAT key is required for correctness.
457  AddGlobalCtor(Fn, 65535, COMDATKey);
458  } else if (D->hasAttr<SelectAnyAttr>()) {
459  // SelectAny globals will be comdat-folded. Put the initializer into a
460  // COMDAT group associated with the global, so the initializers get folded
461  // too.
462  AddGlobalCtor(Fn, 65535, COMDATKey);
463  } else {
464  I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
465  if (I == DelayedCXXInitPosition.end()) {
466  CXXGlobalInits.push_back(Fn);
467  } else if (I->second != ~0U) {
468  assert(I->second < CXXGlobalInits.size() &&
469  CXXGlobalInits[I->second] == nullptr);
470  CXXGlobalInits[I->second] = Fn;
471  }
472  }
473 
474  // Remember that we already emitted the initializer for this global.
475  DelayedCXXInitPosition[D] = ~0U;
476 }
477 
478 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
479  getCXXABI().EmitThreadLocalInitFuncs(
480  *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
481 
482  CXXThreadLocalInits.clear();
483  CXXThreadLocalInitVars.clear();
484  CXXThreadLocals.clear();
485 }
486 
487 void
488 CodeGenModule::EmitCXXGlobalInitFunc() {
489  while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
490  CXXGlobalInits.pop_back();
491 
492  if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
493  return;
494 
495  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
497 
498  // Create our global initialization function.
499  if (!PrioritizedCXXGlobalInits.empty()) {
500  SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
501  llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
502  PrioritizedCXXGlobalInits.end());
503  // Iterate over "chunks" of ctors with same priority and emit each chunk
504  // into separate function. Note - everything is sorted first by priority,
505  // second - by lex order, so we emit ctor functions in proper order.
507  I = PrioritizedCXXGlobalInits.begin(),
508  E = PrioritizedCXXGlobalInits.end(); I != E; ) {
510  PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
511 
512  LocalCXXGlobalInits.clear();
513  unsigned Priority = I->first.priority;
514  // Compute the function suffix from priority. Prepend with zeroes to make
515  // sure the function names are also ordered as priorities.
516  std::string PrioritySuffix = llvm::utostr(Priority);
517  // Priority is always <= 65535 (enforced by sema).
518  PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
519  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
520  FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
521 
522  for (; I < PrioE; ++I)
523  LocalCXXGlobalInits.push_back(I->second);
524 
525  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
526  AddGlobalCtor(Fn, Priority);
527  }
528  PrioritizedCXXGlobalInits.clear();
529  }
530 
531  // Include the filename in the symbol name. Including "sub_" matches gcc and
532  // makes sure these symbols appear lexicographically behind the symbols with
533  // priority emitted above.
534  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
535  if (FileName.empty())
536  FileName = "<null>";
537 
538  for (size_t i = 0; i < FileName.size(); ++i) {
539  // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
540  // to be the set of C preprocessing numbers.
541  if (!isPreprocessingNumberBody(FileName[i]))
542  FileName[i] = '_';
543  }
544 
545  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
546  FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
547 
548  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
549  AddGlobalCtor(Fn);
550 
551  CXXGlobalInits.clear();
552 }
553 
554 void CodeGenModule::EmitCXXGlobalDtorFunc() {
555  if (CXXGlobalDtors.empty())
556  return;
557 
558  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
559 
560  // Create our global destructor function.
562  llvm::Function *Fn =
563  CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
564 
565  CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
566  AddGlobalDtor(Fn);
567 }
568 
569 /// Emit the code necessary to initialize the given global variable.
571  const VarDecl *D,
572  llvm::GlobalVariable *Addr,
573  bool PerformInit) {
574  // Check if we need to emit debug info for variable initializer.
575  if (D->hasAttr<NoDebugAttr>())
576  DebugInfo = nullptr; // disable debug info indefinitely for this function
577 
578  CurEHLocation = D->getBeginLoc();
579 
581  getTypes().arrangeNullaryFunction(),
583  D->getInit()->getExprLoc());
584 
585  // Use guarded initialization if the global variable is weak. This
586  // occurs for, e.g., instantiated static data members and
587  // definitions explicitly marked weak.
588  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
589  EmitCXXGuardedInit(*D, Addr, PerformInit);
590  } else {
591  EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
592  }
593 
594  FinishFunction();
595 }
596 
597 void
600  Address Guard) {
601  {
602  auto NL = ApplyDebugLocation::CreateEmpty(*this);
604  getTypes().arrangeNullaryFunction(), FunctionArgList());
605  // Emit an artificial location for this function.
606  auto AL = ApplyDebugLocation::CreateArtificial(*this);
607 
608  llvm::BasicBlock *ExitBlock = nullptr;
609  if (Guard.isValid()) {
610  // If we have a guard variable, check whether we've already performed
611  // these initializations. This happens for TLS initialization functions.
612  llvm::Value *GuardVal = Builder.CreateLoad(Guard);
613  llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
614  "guard.uninitialized");
615  llvm::BasicBlock *InitBlock = createBasicBlock("init");
616  ExitBlock = createBasicBlock("exit");
617  EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
618  GuardKind::TlsGuard, nullptr);
619  EmitBlock(InitBlock);
620  // Mark as initialized before initializing anything else. If the
621  // initializers use previously-initialized thread_local vars, that's
622  // probably supposed to be OK, but the standard doesn't say.
623  Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
624  }
625 
626  RunCleanupsScope Scope(*this);
627 
628  // When building in Objective-C++ ARC mode, create an autorelease pool
629  // around the global initializers.
630  if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
633  }
634 
635  for (unsigned i = 0, e = Decls.size(); i != e; ++i)
636  if (Decls[i])
637  EmitRuntimeCall(Decls[i]);
638 
639  Scope.ForceCleanup();
640 
641  if (ExitBlock) {
642  Builder.CreateBr(ExitBlock);
643  EmitBlock(ExitBlock);
644  }
645  }
646 
647  FinishFunction();
648 }
649 
651  llvm::Function *Fn,
652  const std::vector<std::pair<llvm::WeakTrackingVH, llvm::Constant *>>
653  &DtorsAndObjects) {
654  {
655  auto NL = ApplyDebugLocation::CreateEmpty(*this);
657  getTypes().arrangeNullaryFunction(), FunctionArgList());
658  // Emit an artificial location for this function.
659  auto AL = ApplyDebugLocation::CreateArtificial(*this);
660 
661  // Emit the dtors, in reverse order from construction.
662  for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
663  llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
664  llvm::CallInst *CI = Builder.CreateCall(Callee,
665  DtorsAndObjects[e - i - 1].second);
666  // Make sure the call and the callee agree on calling convention.
667  if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
668  CI->setCallingConv(F->getCallingConv());
669  }
670  }
671 
672  FinishFunction();
673 }
674 
675 /// generateDestroyHelper - Generates a helper function which, when
676 /// invoked, destroys the given object. The address of the object
677 /// should be in global memory.
679  Address addr, QualType type, Destroyer *destroyer,
680  bool useEHCleanupForArray, const VarDecl *VD) {
681  FunctionArgList args;
684  args.push_back(&Dst);
685 
686  const CGFunctionInfo &FI =
688  llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
689  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
690  FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
691 
692  CurEHLocation = VD->getBeginLoc();
693 
694  StartFunction(VD, getContext().VoidTy, fn, FI, args);
695 
696  emitDestroy(addr, type, destroyer, useEHCleanupForArray);
697 
698  FinishFunction();
699 
700  return fn;
701 }
const CGFunctionInfo & arrangeBuiltinFunctionDeclaration(QualType resultType, const FunctionArgList &args)
A builtin function is a freestanding function using the default C conventions.
Definition: CGCall.cpp:653
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:270
llvm::IntegerType * IntTy
int
Other implicit parameter.
Definition: Decl.h:1511
Destroyer * getDestroyer(QualType::DestructionKind destructionKind)
Definition: CGDecl.cpp:1649
A (possibly-)qualified type.
Definition: Type.h:642
const CodeGenOptions & getCodeGenOpts() const
llvm::LLVMContext & getLLVMContext()
void GenerateCXXGlobalInitFunc(llvm::Function *Fn, ArrayRef< llvm::Function *> CXXThreadLocals, Address Guard=Address::invalid())
GenerateCXXGlobalInitFunc - Generates code for initializing global variables.
Definition: CGDeclCXX.cpp:598
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:2329
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.
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
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:1724
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:6282
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:570
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:708
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:234
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.
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: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:1605
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:256
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:678
This represents one expression.
Definition: Expr.h:105
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:695
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2700
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:1936
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:145
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:201
bool hasGlobalStorage() const
Returns true for all variables that do not have local storage.
Definition: Decl.h:1077
CanQualType VoidTy
Definition: ASTContext.h:1025
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
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
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:1773
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:445
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:307
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:2442
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:650
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:725
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:2505
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:125
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:1544