clang  9.0.0svn
CGDeclCXX.cpp
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1 //===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code dealing with code generation of C++ declarations
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CodeGenFunction.h"
14 #include "CGCXXABI.h"
15 #include "CGObjCRuntime.h"
16 #include "CGOpenMPRuntime.h"
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/IR/Intrinsics.h"
20 #include "llvm/IR/MDBuilder.h"
21 #include "llvm/Support/Path.h"
22 
23 using namespace clang;
24 using namespace CodeGen;
25 
26 static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
27  ConstantAddress DeclPtr) {
28  assert(
29  (D.hasGlobalStorage() ||
30  (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) &&
31  "VarDecl must have global or local (in the case of OpenCL) storage!");
32  assert(!D.getType()->isReferenceType() &&
33  "Should not call EmitDeclInit on a reference!");
34 
35  QualType type = D.getType();
36  LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
37 
38  const Expr *Init = D.getInit();
39  switch (CGF.getEvaluationKind(type)) {
40  case TEK_Scalar: {
41  CodeGenModule &CGM = CGF.CGM;
42  if (lv.isObjCStrong())
44  DeclPtr, D.getTLSKind());
45  else if (lv.isObjCWeak())
47  DeclPtr);
48  else
49  CGF.EmitScalarInit(Init, &D, lv, false);
50  return;
51  }
52  case TEK_Complex:
53  CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
54  return;
55  case TEK_Aggregate:
60  return;
61  }
62  llvm_unreachable("bad evaluation kind");
63 }
64 
65 /// Emit code to cause the destruction of the given variable with
66 /// static storage duration.
67 static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
68  ConstantAddress Addr) {
69  // Honor __attribute__((no_destroy)) and bail instead of attempting
70  // to emit a reference to a possibly nonexistent destructor, which
71  // in turn can cause a crash. This will result in a global constructor
72  // that isn't balanced out by a destructor call as intended by the
73  // attribute. This also checks for -fno-c++-static-destructors and
74  // bails even if the attribute is not present.
75  if (D.isNoDestroy(CGF.getContext()))
76  return;
77 
78  CodeGenModule &CGM = CGF.CGM;
79 
80  // FIXME: __attribute__((cleanup)) ?
81 
82  QualType Type = D.getType();
84 
85  switch (DtorKind) {
86  case QualType::DK_none:
87  return;
88 
90  break;
91 
95  // We don't care about releasing objects during process teardown.
96  assert(!D.getTLSKind() && "should have rejected this");
97  return;
98  }
99 
100  llvm::FunctionCallee Func;
101  llvm::Constant *Argument;
102 
103  // Special-case non-array C++ destructors, if they have the right signature.
104  // Under some ABIs, destructors return this instead of void, and cannot be
105  // passed directly to __cxa_atexit if the target does not allow this
106  // mismatch.
107  const CXXRecordDecl *Record = Type->getAsCXXRecordDecl();
108  bool CanRegisterDestructor =
109  Record && (!CGM.getCXXABI().HasThisReturn(
110  GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
112  // If __cxa_atexit is disabled via a flag, a different helper function is
113  // generated elsewhere which uses atexit instead, and it takes the destructor
114  // directly.
115  bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
116  if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
117  assert(!Record->hasTrivialDestructor());
118  CXXDestructorDecl *Dtor = Record->getDestructor();
119 
121  Argument = llvm::ConstantExpr::getBitCast(
122  Addr.getPointer(), CGF.getTypes().ConvertType(Type)->getPointerTo());
123 
124  // Otherwise, the standard logic requires a helper function.
125  } else {
126  Func = CodeGenFunction(CGM)
127  .generateDestroyHelper(Addr, Type, CGF.getDestroyer(DtorKind),
128  CGF.needsEHCleanup(DtorKind), &D);
129  Argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
130  }
131 
132  CGM.getCXXABI().registerGlobalDtor(CGF, D, Func, Argument);
133 }
134 
135 /// Emit code to cause the variable at the given address to be considered as
136 /// constant from this point onwards.
137 static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
138  llvm::Constant *Addr) {
139  return CGF.EmitInvariantStart(
140  Addr, CGF.getContext().getTypeSizeInChars(D.getType()));
141 }
142 
143 void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
144  // Do not emit the intrinsic if we're not optimizing.
145  if (!CGM.getCodeGenOpts().OptimizationLevel)
146  return;
147 
148  // Grab the llvm.invariant.start intrinsic.
149  llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
150  // Overloaded address space type.
151  llvm::Type *ObjectPtr[1] = {Int8PtrTy};
152  llvm::Function *InvariantStart = CGM.getIntrinsic(InvStartID, ObjectPtr);
153 
154  // Emit a call with the size in bytes of the object.
155  uint64_t Width = Size.getQuantity();
156  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
157  llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
158  Builder.CreateCall(InvariantStart, Args);
159 }
160 
162  llvm::Constant *DeclPtr,
163  bool PerformInit) {
164 
165  const Expr *Init = D.getInit();
166  QualType T = D.getType();
167 
168  // The address space of a static local variable (DeclPtr) may be different
169  // from the address space of the "this" argument of the constructor. In that
170  // case, we need an addrspacecast before calling the constructor.
171  //
172  // struct StructWithCtor {
173  // __device__ StructWithCtor() {...}
174  // };
175  // __device__ void foo() {
176  // __shared__ StructWithCtor s;
177  // ...
178  // }
179  //
180  // For example, in the above CUDA code, the static local variable s has a
181  // "shared" address space qualifier, but the constructor of StructWithCtor
182  // expects "this" in the "generic" address space.
183  unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
184  unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
185  if (ActualAddrSpace != ExpectedAddrSpace) {
187  llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
188  DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
189  }
190 
191  ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
192 
193  if (!T->isReferenceType()) {
194  if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
195  D.hasAttr<OMPThreadPrivateDeclAttr>()) {
196  (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
197  &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
198  PerformInit, this);
199  }
200  if (PerformInit)
201  EmitDeclInit(*this, D, DeclAddr);
202  if (CGM.isTypeConstant(D.getType(), true))
203  EmitDeclInvariant(*this, D, DeclPtr);
204  else
205  EmitDeclDestroy(*this, D, DeclAddr);
206  return;
207  }
208 
209  assert(PerformInit && "cannot have constant initializer which needs "
210  "destruction for reference");
212  EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
213 }
214 
215 /// Create a stub function, suitable for being passed to atexit,
216 /// which passes the given address to the given destructor function.
217 llvm::Function *CodeGenFunction::createAtExitStub(const VarDecl &VD,
218  llvm::FunctionCallee dtor,
219  llvm::Constant *addr) {
220  // Get the destructor function type, void(*)(void).
221  llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
222  SmallString<256> FnName;
223  {
224  llvm::raw_svector_ostream Out(FnName);
226  }
227 
229  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
230  ty, FnName.str(), FI, VD.getLocation());
231 
232  CodeGenFunction CGF(CGM);
233 
235  CGM.getContext().VoidTy, fn, FI, FunctionArgList());
236 
237  llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
238 
239  // Make sure the call and the callee agree on calling convention.
240  if (llvm::Function *dtorFn =
241  dyn_cast<llvm::Function>(dtor.getCallee()->stripPointerCasts()))
242  call->setCallingConv(dtorFn->getCallingConv());
243 
244  CGF.FinishFunction();
245 
246  return fn;
247 }
248 
249 /// Register a global destructor using the C atexit runtime function.
251  llvm::FunctionCallee dtor,
252  llvm::Constant *addr) {
253  // Create a function which calls the destructor.
254  llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
256 }
257 
258 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
259  // extern "C" int atexit(void (*f)(void));
260  llvm::FunctionType *atexitTy =
261  llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
262 
263  llvm::FunctionCallee atexit =
264  CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
265  /*Local=*/true);
266  if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit.getCallee()))
267  atexitFn->setDoesNotThrow();
268 
269  EmitNounwindRuntimeCall(atexit, dtorStub);
270 }
271 
273  llvm::GlobalVariable *DeclPtr,
274  bool PerformInit) {
275  // If we've been asked to forbid guard variables, emit an error now.
276  // This diagnostic is hard-coded for Darwin's use case; we can find
277  // better phrasing if someone else needs it.
278  if (CGM.getCodeGenOpts().ForbidGuardVariables)
279  CGM.Error(D.getLocation(),
280  "this initialization requires a guard variable, which "
281  "the kernel does not support");
282 
283  CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
284 }
285 
287  llvm::BasicBlock *InitBlock,
288  llvm::BasicBlock *NoInitBlock,
289  GuardKind Kind,
290  const VarDecl *D) {
291  assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
292 
293  // A guess at how many times we will enter the initialization of a
294  // variable, depending on the kind of variable.
295  static const uint64_t InitsPerTLSVar = 1024;
296  static const uint64_t InitsPerLocalVar = 1024 * 1024;
297 
298  llvm::MDNode *Weights;
299  if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
300  // For non-local variables, don't apply any weighting for now. Due to our
301  // use of COMDATs, we expect there to be at most one initialization of the
302  // variable per DSO, but we have no way to know how many DSOs will try to
303  // initialize the variable.
304  Weights = nullptr;
305  } else {
306  uint64_t NumInits;
307  // FIXME: For the TLS case, collect and use profiling information to
308  // determine a more accurate brach weight.
309  if (Kind == GuardKind::TlsGuard || D->getTLSKind())
310  NumInits = InitsPerTLSVar;
311  else
312  NumInits = InitsPerLocalVar;
313 
314  // The probability of us entering the initializer is
315  // 1 / (total number of times we attempt to initialize the variable).
316  llvm::MDBuilder MDHelper(CGM.getLLVMContext());
317  Weights = MDHelper.createBranchWeights(1, NumInits - 1);
318  }
319 
320  Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
321 }
322 
324  llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
325  SourceLocation Loc, bool TLS) {
326  llvm::Function *Fn =
328  Name, &getModule());
329  if (!getLangOpts().AppleKext && !TLS) {
330  // Set the section if needed.
331  if (const char *Section = getTarget().getStaticInitSectionSpecifier())
332  Fn->setSection(Section);
333  }
334 
335  SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
336 
337  Fn->setCallingConv(getRuntimeCC());
338 
339  if (!getLangOpts().Exceptions)
340  Fn->setDoesNotThrow();
341 
342  if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
343  !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
344  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
345 
346  if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
347  !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
348  Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
349 
350  if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
351  !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
352  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
353 
354  if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
355  !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
356  Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
357 
358  if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
359  !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
360  Fn->addFnAttr(llvm::Attribute::SanitizeThread);
361 
362  if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
363  !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
364  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
365 
366  if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
367  !isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
368  Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
369 
370  if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
371  !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
372  Fn->addFnAttr(llvm::Attribute::SafeStack);
373 
374  if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
375  !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
376  Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
377 
378  auto RASignKind = getCodeGenOpts().getSignReturnAddress();
380  Fn->addFnAttr("sign-return-address",
382  ? "all"
383  : "non-leaf");
384  auto RASignKey = getCodeGenOpts().getSignReturnAddressKey();
385  Fn->addFnAttr("sign-return-address-key",
386  RASignKey == CodeGenOptions::SignReturnAddressKeyValue::AKey
387  ? "a_key"
388  : "b_key");
389  }
390 
391  if (getCodeGenOpts().BranchTargetEnforcement)
392  Fn->addFnAttr("branch-target-enforcement");
393 
394  return Fn;
395 }
396 
397 /// Create a global pointer to a function that will initialize a global
398 /// variable. The user has requested that this pointer be emitted in a specific
399 /// section.
400 void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
401  llvm::GlobalVariable *GV,
402  llvm::Function *InitFunc,
403  InitSegAttr *ISA) {
404  llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
405  TheModule, InitFunc->getType(), /*isConstant=*/true,
406  llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
407  PtrArray->setSection(ISA->getSection());
408  addUsedGlobal(PtrArray);
409 
410  // If the GV is already in a comdat group, then we have to join it.
411  if (llvm::Comdat *C = GV->getComdat())
412  PtrArray->setComdat(C);
413 }
414 
415 void
416 CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
417  llvm::GlobalVariable *Addr,
418  bool PerformInit) {
419 
420  // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
421  // __constant__ and __shared__ variables defined in namespace scope,
422  // that are of class type, cannot have a non-empty constructor. All
423  // the checks have been done in Sema by now. Whatever initializers
424  // are allowed are empty and we just need to ignore them here.
425  if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
426  (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
427  D->hasAttr<CUDASharedAttr>()))
428  return;
429 
430  if (getLangOpts().OpenMP &&
431  getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
432  return;
433 
434  // Check if we've already initialized this decl.
435  auto I = DelayedCXXInitPosition.find(D);
436  if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
437  return;
438 
439  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
440  SmallString<256> FnName;
441  {
442  llvm::raw_svector_ostream Out(FnName);
443  getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
444  }
445 
446  // Create a variable initialization function.
447  llvm::Function *Fn =
448  CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
450  D->getLocation());
451 
452  auto *ISA = D->getAttr<InitSegAttr>();
454  PerformInit);
455 
456  llvm::GlobalVariable *COMDATKey =
457  supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
458 
459  if (D->getTLSKind()) {
460  // FIXME: Should we support init_priority for thread_local?
461  // FIXME: We only need to register one __cxa_thread_atexit function for the
462  // entire TU.
463  CXXThreadLocalInits.push_back(Fn);
464  CXXThreadLocalInitVars.push_back(D);
465  } else if (PerformInit && ISA) {
466  EmitPointerToInitFunc(D, Addr, Fn, ISA);
467  } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
468  OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
469  PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
472  // C++ [basic.start.init]p2:
473  // Definitions of explicitly specialized class template static data
474  // members have ordered initialization. Other class template static data
475  // members (i.e., implicitly or explicitly instantiated specializations)
476  // have unordered initialization.
477  //
478  // As a consequence, we can put them into their own llvm.global_ctors entry.
479  //
480  // If the global is externally visible, put the initializer into a COMDAT
481  // group with the global being initialized. On most platforms, this is a
482  // minor startup time optimization. In the MS C++ ABI, there are no guard
483  // variables, so this COMDAT key is required for correctness.
484  AddGlobalCtor(Fn, 65535, COMDATKey);
485  if (getTarget().getCXXABI().isMicrosoft() && COMDATKey) {
486  // In The MS C++, MS add template static data member in the linker
487  // drective.
488  addUsedGlobal(COMDATKey);
489  }
490  } else if (D->hasAttr<SelectAnyAttr>()) {
491  // SelectAny globals will be comdat-folded. Put the initializer into a
492  // COMDAT group associated with the global, so the initializers get folded
493  // too.
494  AddGlobalCtor(Fn, 65535, COMDATKey);
495  } else {
496  I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
497  if (I == DelayedCXXInitPosition.end()) {
498  CXXGlobalInits.push_back(Fn);
499  } else if (I->second != ~0U) {
500  assert(I->second < CXXGlobalInits.size() &&
501  CXXGlobalInits[I->second] == nullptr);
502  CXXGlobalInits[I->second] = Fn;
503  }
504  }
505 
506  // Remember that we already emitted the initializer for this global.
507  DelayedCXXInitPosition[D] = ~0U;
508 }
509 
510 void CodeGenModule::EmitCXXThreadLocalInitFunc() {
511  getCXXABI().EmitThreadLocalInitFuncs(
512  *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
513 
514  CXXThreadLocalInits.clear();
515  CXXThreadLocalInitVars.clear();
516  CXXThreadLocals.clear();
517 }
518 
519 void
520 CodeGenModule::EmitCXXGlobalInitFunc() {
521  while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
522  CXXGlobalInits.pop_back();
523 
524  if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
525  return;
526 
527  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
529 
530  // Create our global initialization function.
531  if (!PrioritizedCXXGlobalInits.empty()) {
532  SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
533  llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
534  PrioritizedCXXGlobalInits.end());
535  // Iterate over "chunks" of ctors with same priority and emit each chunk
536  // into separate function. Note - everything is sorted first by priority,
537  // second - by lex order, so we emit ctor functions in proper order.
539  I = PrioritizedCXXGlobalInits.begin(),
540  E = PrioritizedCXXGlobalInits.end(); I != E; ) {
542  PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
543 
544  LocalCXXGlobalInits.clear();
545  unsigned Priority = I->first.priority;
546  // Compute the function suffix from priority. Prepend with zeroes to make
547  // sure the function names are also ordered as priorities.
548  std::string PrioritySuffix = llvm::utostr(Priority);
549  // Priority is always <= 65535 (enforced by sema).
550  PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
551  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
552  FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
553 
554  for (; I < PrioE; ++I)
555  LocalCXXGlobalInits.push_back(I->second);
556 
557  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
558  AddGlobalCtor(Fn, Priority);
559  }
560  PrioritizedCXXGlobalInits.clear();
561  }
562 
563  // Include the filename in the symbol name. Including "sub_" matches gcc and
564  // makes sure these symbols appear lexicographically behind the symbols with
565  // priority emitted above.
566  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
567  if (FileName.empty())
568  FileName = "<null>";
569 
570  for (size_t i = 0; i < FileName.size(); ++i) {
571  // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
572  // to be the set of C preprocessing numbers.
573  if (!isPreprocessingNumberBody(FileName[i]))
574  FileName[i] = '_';
575  }
576 
577  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
578  FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
579 
580  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
581  AddGlobalCtor(Fn);
582 
583  // In OpenCL global init functions must be converted to kernels in order to
584  // be able to launch them from the host.
585  // FIXME: Some more work might be needed to handle destructors correctly.
586  // Current initialization function makes use of function pointers callbacks.
587  // We can't support function pointers especially between host and device.
588  // However it seems global destruction has little meaning without any
589  // dynamic resource allocation on the device and program scope variables are
590  // destroyed by the runtime when program is released.
591  if (getLangOpts().OpenCL) {
592  GenOpenCLArgMetadata(Fn);
593  Fn->setCallingConv(llvm::CallingConv::SPIR_KERNEL);
594  }
595 
596  CXXGlobalInits.clear();
597 }
598 
599 void CodeGenModule::EmitCXXGlobalDtorFunc() {
600  if (CXXGlobalDtors.empty())
601  return;
602 
603  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
604 
605  // Create our global destructor function.
607  llvm::Function *Fn =
608  CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
609 
610  CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
611  AddGlobalDtor(Fn);
612 }
613 
614 /// Emit the code necessary to initialize the given global variable.
616  const VarDecl *D,
617  llvm::GlobalVariable *Addr,
618  bool PerformInit) {
619  // Check if we need to emit debug info for variable initializer.
620  if (D->hasAttr<NoDebugAttr>())
621  DebugInfo = nullptr; // disable debug info indefinitely for this function
622 
623  CurEHLocation = D->getBeginLoc();
624 
626  getContext().VoidTy, Fn, getTypes().arrangeNullaryFunction(),
628  D->getInit()->getExprLoc());
629 
630  // Use guarded initialization if the global variable is weak. This
631  // occurs for, e.g., instantiated static data members and
632  // definitions explicitly marked weak.
633  //
634  // Also use guarded initialization for a variable with dynamic TLS and
635  // unordered initialization. (If the initialization is ordered, the ABI
636  // layer will guard the whole-TU initialization for us.)
637  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage() ||
638  (D->getTLSKind() == VarDecl::TLS_Dynamic &&
640  EmitCXXGuardedInit(*D, Addr, PerformInit);
641  } else {
642  EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
643  }
644 
645  FinishFunction();
646 }
647 
648 void
651  ConstantAddress Guard) {
652  {
653  auto NL = ApplyDebugLocation::CreateEmpty(*this);
655  getTypes().arrangeNullaryFunction(), FunctionArgList());
656  // Emit an artificial location for this function.
657  auto AL = ApplyDebugLocation::CreateArtificial(*this);
658 
659  llvm::BasicBlock *ExitBlock = nullptr;
660  if (Guard.isValid()) {
661  // If we have a guard variable, check whether we've already performed
662  // these initializations. This happens for TLS initialization functions.
663  llvm::Value *GuardVal = Builder.CreateLoad(Guard);
664  llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
665  "guard.uninitialized");
666  llvm::BasicBlock *InitBlock = createBasicBlock("init");
667  ExitBlock = createBasicBlock("exit");
668  EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
669  GuardKind::TlsGuard, nullptr);
670  EmitBlock(InitBlock);
671  // Mark as initialized before initializing anything else. If the
672  // initializers use previously-initialized thread_local vars, that's
673  // probably supposed to be OK, but the standard doesn't say.
674  Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
675 
676  // The guard variable can't ever change again.
678  Guard.getPointer(),
680  CGM.getDataLayout().getTypeAllocSize(GuardVal->getType())));
681  }
682 
683  RunCleanupsScope Scope(*this);
684 
685  // When building in Objective-C++ ARC mode, create an autorelease pool
686  // around the global initializers.
687  if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
690  }
691 
692  for (unsigned i = 0, e = Decls.size(); i != e; ++i)
693  if (Decls[i])
694  EmitRuntimeCall(Decls[i]);
695 
696  Scope.ForceCleanup();
697 
698  if (ExitBlock) {
699  Builder.CreateBr(ExitBlock);
700  EmitBlock(ExitBlock);
701  }
702  }
703 
704  FinishFunction();
705 }
706 
708  llvm::Function *Fn,
709  const std::vector<std::tuple<llvm::FunctionType *, llvm::WeakTrackingVH,
710  llvm::Constant *>> &DtorsAndObjects) {
711  {
712  auto NL = ApplyDebugLocation::CreateEmpty(*this);
714  getTypes().arrangeNullaryFunction(), FunctionArgList());
715  // Emit an artificial location for this function.
716  auto AL = ApplyDebugLocation::CreateArtificial(*this);
717 
718  // Emit the dtors, in reverse order from construction.
719  for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
720  llvm::FunctionType *CalleeTy;
721  llvm::Value *Callee;
722  llvm::Constant *Arg;
723  std::tie(CalleeTy, Callee, Arg) = DtorsAndObjects[e - i - 1];
724  llvm::CallInst *CI = Builder.CreateCall(CalleeTy, Callee, Arg);
725  // Make sure the call and the callee agree on calling convention.
726  if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
727  CI->setCallingConv(F->getCallingConv());
728  }
729  }
730 
731  FinishFunction();
732 }
733 
734 /// generateDestroyHelper - Generates a helper function which, when
735 /// invoked, destroys the given object. The address of the object
736 /// should be in global memory.
738  Address addr, QualType type, Destroyer *destroyer,
739  bool useEHCleanupForArray, const VarDecl *VD) {
740  FunctionArgList args;
743  args.push_back(&Dst);
744 
745  const CGFunctionInfo &FI =
747  llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
748  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
749  FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
750 
751  CurEHLocation = VD->getBeginLoc();
752 
753  StartFunction(VD, getContext().VoidTy, fn, FI, args);
754 
755  emitDestroy(addr, type, destroyer, useEHCleanupForArray);
756 
757  FinishFunction();
758 
759  return fn;
760 }
const CGFunctionInfo & arrangeBuiltinFunctionDeclaration(QualType resultType, const FunctionArgList &args)
A builtin function is a freestanding function using the default C conventions.
Definition: CGCall.cpp:652
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:286
llvm::IntegerType * IntTy
int
Other implicit parameter.
Definition: Decl.h:1524
Destroyer * getDestroyer(QualType::DestructionKind destructionKind)
Definition: CGDecl.cpp:2026
A (possibly-)qualified type.
Definition: Type.h:643
const CodeGenOptions & getCodeGenOpts() const
llvm::LLVMContext & getLLVMContext()
The base class of the type hierarchy.
Definition: Type.h:1418
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:2484
llvm::Type * ConvertTypeForMem(QualType T)
ConvertTypeForMem - Convert type T into a llvm::Type.
long i
Definition: xmmintrin.h:1456
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:2101
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:592
bool isReferenceType() const
Definition: Type.h:6363
void registerGlobalDtorWithAtExit(const VarDecl &D, llvm::FunctionCallee fn, llvm::Constant *addr)
Call atexit() with a function that passes the given argument to the given function.
Definition: CGDeclCXX.cpp:250
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:615
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:730
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:37
llvm::CallInst * EmitRuntimeCall(llvm::FunctionCallee callee, const Twine &name="")
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:2505
bool needsEHCleanup(QualType::DestructionKind kind)
Determines whether an EH cleanup is required to destroy a type with the given destruction kind...
bool isObjCWeak() const
Definition: CGValue.h:293
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:1491
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1736
virtual bool canCallMismatchedFunctionType() const
Returns true if the target allows calling a function through a pointer with a different signature tha...
Definition: CGCXXABI.h:118
constexpr XRayInstrMask All
Definition: XRayInstr.h:41
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:542
bool isValid() const
Definition: Address.h:35
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1636
RValue - This trivial value class is used to represent the result of an expression that is evaluated...
Definition: CGValue.h:38
virtual void mangleDynamicAtExitDestructor(const VarDecl *D, raw_ostream &)=0
QuantityType getQuantity() const
getQuantity - Get the raw integer representation of this quantity.
Definition: CharUnits.h:178
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:106
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:272
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:737
This represents one expression.
Definition: Expr.h:108
bool hasLocalStorage() const
Returns true if a variable with function scope is a non-static local variable.
Definition: Decl.h:1035
Enters a new scope for capturing cleanups, all of which will be executed once the scope is exited...
const CGFunctionInfo & arrangeNullaryFunction()
A nullary function is a freestanding function of type &#39;void ()&#39;.
Definition: CGCall.cpp:694
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2830
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:143
TLSKind getTLSKind() const
Definition: Decl.cpp:1970
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:62
void GenerateCXXGlobalInitFunc(llvm::Function *Fn, ArrayRef< llvm::Function *> CXXThreadLocals, ConstantAddress Guard=ConstantAddress::invalid())
GenerateCXXGlobalInitFunc - Generates code for initializing global variables.
Definition: CGDeclCXX.cpp:649
void EmitCXXGlobalVarDeclInit(const VarDecl &D, llvm::Constant *DeclPtr, bool PerformInit)
EmitCXXGlobalVarDeclInit - Create the initializer for a C++ variable with global storage.
Definition: CGDeclCXX.cpp:161
bool isObjCStrong() const
Definition: CGValue.h:296
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:198
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:40
The l-value was considered opaque, so the alignment was determined from a type.
Kind
Encodes a location in the source.
bool hasGlobalStorage() const
Returns true for all variables that do not have local storage.
Definition: Decl.h:1077
CanQualType VoidTy
Definition: ASTContext.h:1014
An aligned address.
Definition: Address.h:24
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:1163
MangleContext & getMangleContext()
Gets the mangle context.
Definition: CGCXXABI.h:96
Complete object dtor.
Definition: ABI.h:35
constexpr XRayInstrMask None
Definition: XRayInstr.h:37
void Error(SourceLocation loc, StringRef error)
Emit a general error that something can&#39;t be done.
void FinishFunction(SourceLocation EndLoc=SourceLocation())
FinishFunction - Complete IR generation of the current function.
SourceLocation getExprLoc() const LLVM_READONLY
getExprLoc - Return the preferred location for the arrow when diagnosing a problem with a generic exp...
Definition: Expr.cpp:215
llvm::Value * EmitScalarExpr(const Expr *E, bool IgnoreResultAssign=false)
EmitScalarExpr - Emit the computation of the specified expression of LLVM scalar type, returning the result.
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:358
llvm::Value * getScalarVal() const
getScalarVal() - Return the Value* of this scalar value.
Definition: CGValue.h:58
TLS with a dynamic initializer.
Definition: Decl.h:835
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:83
llvm::LoadInst * CreateLoad(Address Addr, const llvm::Twine &Name="")
Definition: CGBuilder.h:69
virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, llvm::FunctionCallee Dtor, llvm::Constant *Addr)=0
Emit code to force the execution of a destructor during global teardown.
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:67
llvm::Function * getIntrinsic(unsigned IID, ArrayRef< llvm::Type *> Tys=None)
llvm::StoreInst * CreateStore(llvm::Value *Val, Address Addr, bool IsVolatile=false)
Definition: CGBuilder.h:107
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:539
LValue MakeAddrLValue(Address Addr, QualType T, AlignmentSource Source=AlignmentSource::Type)
llvm::Function * createAtExitStub(const VarDecl &VD, llvm::FunctionCallee 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:217
void EmitAggExpr(const Expr *E, AggValueSlot AS)
EmitAggExpr - Emit the computation of the specified expression of aggregate type. ...
Definition: CGExprAgg.cpp:1826
GVALinkage GetGVALinkageForVariable(const VarDecl *VD)
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:538
void EmitScalarInit(const Expr *init, const ValueDecl *D, LValue lvalue, bool capturedByInit)
Definition: CGDecl.cpp:744
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:31
llvm::FunctionCallee CreateRuntimeFunction(llvm::FunctionType *Ty, StringRef Name, llvm::AttributeList ExtraAttrs=llvm::AttributeList(), bool Local=false)
Create or return a runtime function declaration with the specified type and name. ...
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:450
static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D, ConstantAddress DeclPtr)
Definition: CGDeclCXX.cpp:26
llvm::FunctionCallee getAddrAndTypeOfCXXStructor(GlobalDecl GD, const CGFunctionInfo *FnInfo=nullptr, llvm::FunctionType *FnType=nullptr, bool DontDefer=false, ForDefinition_t IsForDefinition=NotForDefinition)
Definition: CGCXX.cpp:220
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:323
A specialization of Address that requires the address to be an LLVM Constant.
Definition: Address.h:74
void GenerateCXXGlobalDtorsFunc(llvm::Function *Fn, const std::vector< std::tuple< llvm::FunctionType *, llvm::WeakTrackingVH, llvm::Constant *>> &DtorsAndObjects)
GenerateCXXGlobalDtorsFunc - Generates code for destroying global variables.
Definition: CGDeclCXX.cpp:707
CGCXXABI & getCXXABI() const
void EmitObjCAutoreleasePoolCleanup(llvm::Value *Ptr)
Definition: CGObjC.cpp:2680
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:747
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:166
const LangOptions & getLangOpts() const
unsigned getTargetAddressSpace(QualType T) const
Definition: ASTContext.h:2532
llvm::CallInst * EmitNounwindRuntimeCall(llvm::FunctionCallee callee, const Twine &name="")
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:147
const LangOptions & getLangOpts() const
Definition: ASTContext.h:710
SourceLocation getLocation() const
Definition: DeclBase.h:429
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:137
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:1541
bool isNoDestroy(const ASTContext &) const
Do we need to emit an exit-time destructor for this variable?
Definition: Decl.cpp:2562