clang  7.0.0svn
CGVTables.cpp
Go to the documentation of this file.
1 //===--- CGVTables.cpp - Emit LLVM Code for C++ vtables -------------------===//
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 C++ code generation of virtual tables.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CGCXXABI.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
18 #include "clang/AST/RecordLayout.h"
22 #include "llvm/IR/IntrinsicInst.h"
23 #include "llvm/Support/Format.h"
24 #include "llvm/Transforms/Utils/Cloning.h"
25 #include <algorithm>
26 #include <cstdio>
27 
28 using namespace clang;
29 using namespace CodeGen;
30 
32  : CGM(CGM), VTContext(CGM.getContext().getVTableContext()) {}
33 
34 llvm::Constant *CodeGenModule::GetAddrOfThunk(StringRef Name, llvm::Type *FnTy,
35  GlobalDecl GD) {
36  return GetOrCreateLLVMFunction(Name, FnTy, GD, /*ForVTable=*/true,
37  /*DontDefer=*/true, /*IsThunk=*/true);
38 }
39 
40 static void setThunkProperties(CodeGenModule &CGM, const ThunkInfo &Thunk,
41  llvm::Function *ThunkFn, bool ForVTable,
42  GlobalDecl GD) {
43  CGM.setFunctionLinkage(GD, ThunkFn);
44  CGM.getCXXABI().setThunkLinkage(ThunkFn, ForVTable, GD,
45  !Thunk.Return.isEmpty());
46 
47  // Set the right visibility.
48  CGM.setGVProperties(ThunkFn, GD);
49 
50  if (!CGM.getCXXABI().exportThunk()) {
51  ThunkFn->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
52  ThunkFn->setDSOLocal(true);
53  }
54 
55  if (CGM.supportsCOMDAT() && ThunkFn->isWeakForLinker())
56  ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
57 }
58 
59 #ifndef NDEBUG
60 static bool similar(const ABIArgInfo &infoL, CanQualType typeL,
61  const ABIArgInfo &infoR, CanQualType typeR) {
62  return (infoL.getKind() == infoR.getKind() &&
63  (typeL == typeR ||
64  (isa<PointerType>(typeL) && isa<PointerType>(typeR)) ||
65  (isa<ReferenceType>(typeL) && isa<ReferenceType>(typeR))));
66 }
67 #endif
68 
70  QualType ResultType, RValue RV,
71  const ThunkInfo &Thunk) {
72  // Emit the return adjustment.
73  bool NullCheckValue = !ResultType->isReferenceType();
74 
75  llvm::BasicBlock *AdjustNull = nullptr;
76  llvm::BasicBlock *AdjustNotNull = nullptr;
77  llvm::BasicBlock *AdjustEnd = nullptr;
78 
79  llvm::Value *ReturnValue = RV.getScalarVal();
80 
81  if (NullCheckValue) {
82  AdjustNull = CGF.createBasicBlock("adjust.null");
83  AdjustNotNull = CGF.createBasicBlock("adjust.notnull");
84  AdjustEnd = CGF.createBasicBlock("adjust.end");
85 
86  llvm::Value *IsNull = CGF.Builder.CreateIsNull(ReturnValue);
87  CGF.Builder.CreateCondBr(IsNull, AdjustNull, AdjustNotNull);
88  CGF.EmitBlock(AdjustNotNull);
89  }
90 
91  auto ClassDecl = ResultType->getPointeeType()->getAsCXXRecordDecl();
92  auto ClassAlign = CGF.CGM.getClassPointerAlignment(ClassDecl);
93  ReturnValue = CGF.CGM.getCXXABI().performReturnAdjustment(CGF,
94  Address(ReturnValue, ClassAlign),
95  Thunk.Return);
96 
97  if (NullCheckValue) {
98  CGF.Builder.CreateBr(AdjustEnd);
99  CGF.EmitBlock(AdjustNull);
100  CGF.Builder.CreateBr(AdjustEnd);
101  CGF.EmitBlock(AdjustEnd);
102 
103  llvm::PHINode *PHI = CGF.Builder.CreatePHI(ReturnValue->getType(), 2);
104  PHI->addIncoming(ReturnValue, AdjustNotNull);
105  PHI->addIncoming(llvm::Constant::getNullValue(ReturnValue->getType()),
106  AdjustNull);
107  ReturnValue = PHI;
108  }
109 
110  return RValue::get(ReturnValue);
111 }
112 
113 /// This function clones a function's DISubprogram node and enters it into
114 /// a value map with the intent that the map can be utilized by the cloner
115 /// to short-circuit Metadata node mapping.
116 /// Furthermore, the function resolves any DILocalVariable nodes referenced
117 /// by dbg.value intrinsics so they can be properly mapped during cloning.
118 static void resolveTopLevelMetadata(llvm::Function *Fn,
119  llvm::ValueToValueMapTy &VMap) {
120  // Clone the DISubprogram node and put it into the Value map.
121  auto *DIS = Fn->getSubprogram();
122  if (!DIS)
123  return;
124  auto *NewDIS = DIS->replaceWithDistinct(DIS->clone());
125  VMap.MD()[DIS].reset(NewDIS);
126 
127  // Find all llvm.dbg.declare intrinsics and resolve the DILocalVariable nodes
128  // they are referencing.
129  for (auto &BB : Fn->getBasicBlockList()) {
130  for (auto &I : BB) {
131  if (auto *DII = dyn_cast<llvm::DbgInfoIntrinsic>(&I)) {
132  auto *DILocal = DII->getVariable();
133  if (!DILocal->isResolved())
134  DILocal->resolve();
135  }
136  }
137  }
138 }
139 
140 // This function does roughly the same thing as GenerateThunk, but in a
141 // very different way, so that va_start and va_end work correctly.
142 // FIXME: This function assumes "this" is the first non-sret LLVM argument of
143 // a function, and that there is an alloca built in the entry block
144 // for all accesses to "this".
145 // FIXME: This function assumes there is only one "ret" statement per function.
146 // FIXME: Cloning isn't correct in the presence of indirect goto!
147 // FIXME: This implementation of thunks bloats codesize by duplicating the
148 // function definition. There are alternatives:
149 // 1. Add some sort of stub support to LLVM for cases where we can
150 // do a this adjustment, then a sibcall.
151 // 2. We could transform the definition to take a va_list instead of an
152 // actual variable argument list, then have the thunks (including a
153 // no-op thunk for the regular definition) call va_start/va_end.
154 // There's a bit of per-call overhead for this solution, but it's
155 // better for codesize if the definition is long.
156 llvm::Function *
158  const CGFunctionInfo &FnInfo,
159  GlobalDecl GD, const ThunkInfo &Thunk) {
160  const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
161  const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
162  QualType ResultType = FPT->getReturnType();
163 
164  // Get the original function
165  assert(FnInfo.isVariadic());
166  llvm::Type *Ty = CGM.getTypes().GetFunctionType(FnInfo);
167  llvm::Value *Callee = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
168  llvm::Function *BaseFn = cast<llvm::Function>(Callee);
169 
170  // Clone to thunk.
171  llvm::ValueToValueMapTy VMap;
172 
173  // We are cloning a function while some Metadata nodes are still unresolved.
174  // Ensure that the value mapper does not encounter any of them.
175  resolveTopLevelMetadata(BaseFn, VMap);
176  llvm::Function *NewFn = llvm::CloneFunction(BaseFn, VMap);
177  Fn->replaceAllUsesWith(NewFn);
178  NewFn->takeName(Fn);
179  Fn->eraseFromParent();
180  Fn = NewFn;
181 
182  // "Initialize" CGF (minimally).
183  CurFn = Fn;
184 
185  // Get the "this" value
186  llvm::Function::arg_iterator AI = Fn->arg_begin();
187  if (CGM.ReturnTypeUsesSRet(FnInfo))
188  ++AI;
189 
190  // Find the first store of "this", which will be to the alloca associated
191  // with "this".
192  Address ThisPtr(&*AI, CGM.getClassPointerAlignment(MD->getParent()));
193  llvm::BasicBlock *EntryBB = &Fn->front();
194  llvm::BasicBlock::iterator ThisStore =
195  std::find_if(EntryBB->begin(), EntryBB->end(), [&](llvm::Instruction &I) {
196  return isa<llvm::StoreInst>(I) &&
197  I.getOperand(0) == ThisPtr.getPointer();
198  });
199  assert(ThisStore != EntryBB->end() &&
200  "Store of this should be in entry block?");
201  // Adjust "this", if necessary.
202  Builder.SetInsertPoint(&*ThisStore);
203  llvm::Value *AdjustedThisPtr =
204  CGM.getCXXABI().performThisAdjustment(*this, ThisPtr, Thunk.This);
205  ThisStore->setOperand(0, AdjustedThisPtr);
206 
207  if (!Thunk.Return.isEmpty()) {
208  // Fix up the returned value, if necessary.
209  for (llvm::BasicBlock &BB : *Fn) {
210  llvm::Instruction *T = BB.getTerminator();
211  if (isa<llvm::ReturnInst>(T)) {
212  RValue RV = RValue::get(T->getOperand(0));
213  T->eraseFromParent();
214  Builder.SetInsertPoint(&BB);
215  RV = PerformReturnAdjustment(*this, ResultType, RV, Thunk);
216  Builder.CreateRet(RV.getScalarVal());
217  break;
218  }
219  }
220  }
221 
222  return Fn;
223 }
224 
225 void CodeGenFunction::StartThunk(llvm::Function *Fn, GlobalDecl GD,
226  const CGFunctionInfo &FnInfo,
227  bool IsUnprototyped) {
228  assert(!CurGD.getDecl() && "CurGD was already set!");
229  CurGD = GD;
230  CurFuncIsThunk = true;
231 
232  // Build FunctionArgs.
233  const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
234  QualType ThisType = MD->getThisType(getContext());
235  const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
236  QualType ResultType;
237  if (IsUnprototyped)
238  ResultType = CGM.getContext().VoidTy;
239  else if (CGM.getCXXABI().HasThisReturn(GD))
240  ResultType = ThisType;
241  else if (CGM.getCXXABI().hasMostDerivedReturn(GD))
242  ResultType = CGM.getContext().VoidPtrTy;
243  else
244  ResultType = FPT->getReturnType();
245  FunctionArgList FunctionArgs;
246 
247  // Create the implicit 'this' parameter declaration.
248  CGM.getCXXABI().buildThisParam(*this, FunctionArgs);
249 
250  // Add the rest of the parameters, if we have a prototype to work with.
251  if (!IsUnprototyped) {
252  FunctionArgs.append(MD->param_begin(), MD->param_end());
253 
254  if (isa<CXXDestructorDecl>(MD))
255  CGM.getCXXABI().addImplicitStructorParams(*this, ResultType,
256  FunctionArgs);
257  }
258 
259  // Start defining the function.
260  auto NL = ApplyDebugLocation::CreateEmpty(*this);
261  StartFunction(GlobalDecl(), ResultType, Fn, FnInfo, FunctionArgs,
262  MD->getLocation());
263  // Create a scope with an artificial location for the body of this function.
264  auto AL = ApplyDebugLocation::CreateArtificial(*this);
265 
266  // Since we didn't pass a GlobalDecl to StartFunction, do this ourselves.
268  CXXThisValue = CXXABIThisValue;
269  CurCodeDecl = MD;
270  CurFuncDecl = MD;
271 }
272 
274  // Clear these to restore the invariants expected by
275  // StartFunction/FinishFunction.
276  CurCodeDecl = nullptr;
277  CurFuncDecl = nullptr;
278 
279  FinishFunction();
280 }
281 
282 void CodeGenFunction::EmitCallAndReturnForThunk(llvm::Constant *CalleePtr,
283  const ThunkInfo *Thunk,
284  bool IsUnprototyped) {
285  assert(isa<CXXMethodDecl>(CurGD.getDecl()) &&
286  "Please use a new CGF for this thunk");
287  const CXXMethodDecl *MD = cast<CXXMethodDecl>(CurGD.getDecl());
288 
289  // Adjust the 'this' pointer if necessary
290  llvm::Value *AdjustedThisPtr =
291  Thunk ? CGM.getCXXABI().performThisAdjustment(
292  *this, LoadCXXThisAddress(), Thunk->This)
293  : LoadCXXThis();
294 
295  if (CurFnInfo->usesInAlloca() || IsUnprototyped) {
296  // We don't handle return adjusting thunks, because they require us to call
297  // the copy constructor. For now, fall through and pretend the return
298  // adjustment was empty so we don't crash.
299  if (Thunk && !Thunk->Return.isEmpty()) {
300  if (IsUnprototyped)
301  CGM.ErrorUnsupported(
302  MD, "return-adjusting thunk with incomplete parameter type");
303  else
304  CGM.ErrorUnsupported(
305  MD, "non-trivial argument copy for return-adjusting thunk");
306  }
307  EmitMustTailThunk(MD, AdjustedThisPtr, CalleePtr);
308  return;
309  }
310 
311  // Start building CallArgs.
312  CallArgList CallArgs;
313  QualType ThisType = MD->getThisType(getContext());
314  CallArgs.add(RValue::get(AdjustedThisPtr), ThisType);
315 
316  if (isa<CXXDestructorDecl>(MD))
317  CGM.getCXXABI().adjustCallArgsForDestructorThunk(*this, CurGD, CallArgs);
318 
319 #ifndef NDEBUG
320  unsigned PrefixArgs = CallArgs.size() - 1;
321 #endif
322  // Add the rest of the arguments.
323  for (const ParmVarDecl *PD : MD->parameters())
324  EmitDelegateCallArg(CallArgs, PD, SourceLocation());
325 
326  const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
327 
328 #ifndef NDEBUG
329  const CGFunctionInfo &CallFnInfo = CGM.getTypes().arrangeCXXMethodCall(
330  CallArgs, FPT, RequiredArgs::forPrototypePlus(FPT, 1, MD), PrefixArgs);
331  assert(CallFnInfo.getRegParm() == CurFnInfo->getRegParm() &&
332  CallFnInfo.isNoReturn() == CurFnInfo->isNoReturn() &&
333  CallFnInfo.getCallingConvention() == CurFnInfo->getCallingConvention());
334  assert(isa<CXXDestructorDecl>(MD) || // ignore dtor return types
335  similar(CallFnInfo.getReturnInfo(), CallFnInfo.getReturnType(),
336  CurFnInfo->getReturnInfo(), CurFnInfo->getReturnType()));
337  assert(CallFnInfo.arg_size() == CurFnInfo->arg_size());
338  for (unsigned i = 0, e = CurFnInfo->arg_size(); i != e; ++i)
339  assert(similar(CallFnInfo.arg_begin()[i].info,
340  CallFnInfo.arg_begin()[i].type,
341  CurFnInfo->arg_begin()[i].info,
342  CurFnInfo->arg_begin()[i].type));
343 #endif
344 
345  // Determine whether we have a return value slot to use.
346  QualType ResultType = CGM.getCXXABI().HasThisReturn(CurGD)
347  ? ThisType
348  : CGM.getCXXABI().hasMostDerivedReturn(CurGD)
349  ? CGM.getContext().VoidPtrTy
350  : FPT->getReturnType();
351  ReturnValueSlot Slot;
352  if (!ResultType->isVoidType() &&
353  CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect &&
354  !hasScalarEvaluationKind(CurFnInfo->getReturnType()))
355  Slot = ReturnValueSlot(ReturnValue, ResultType.isVolatileQualified());
356 
357  // Now emit our call.
358  llvm::Instruction *CallOrInvoke;
359  CGCallee Callee = CGCallee::forDirect(CalleePtr, MD);
360  RValue RV = EmitCall(*CurFnInfo, Callee, Slot, CallArgs, &CallOrInvoke);
361 
362  // Consider return adjustment if we have ThunkInfo.
363  if (Thunk && !Thunk->Return.isEmpty())
364  RV = PerformReturnAdjustment(*this, ResultType, RV, *Thunk);
365  else if (llvm::CallInst* Call = dyn_cast<llvm::CallInst>(CallOrInvoke))
366  Call->setTailCallKind(llvm::CallInst::TCK_Tail);
367 
368  // Emit return.
369  if (!ResultType->isVoidType() && Slot.isNull())
370  CGM.getCXXABI().EmitReturnFromThunk(*this, RV, ResultType);
371 
372  // Disable the final ARC autorelease.
373  AutoreleaseResult = false;
374 
375  FinishThunk();
376 }
377 
379  llvm::Value *AdjustedThisPtr,
380  llvm::Value *CalleePtr) {
381  // Emitting a musttail call thunk doesn't use any of the CGCall.cpp machinery
382  // to translate AST arguments into LLVM IR arguments. For thunks, we know
383  // that the caller prototype more or less matches the callee prototype with
384  // the exception of 'this'.
386  for (llvm::Argument &A : CurFn->args())
387  Args.push_back(&A);
388 
389  // Set the adjusted 'this' pointer.
390  const ABIArgInfo &ThisAI = CurFnInfo->arg_begin()->info;
391  if (ThisAI.isDirect()) {
392  const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
393  int ThisArgNo = RetAI.isIndirect() && !RetAI.isSRetAfterThis() ? 1 : 0;
394  llvm::Type *ThisType = Args[ThisArgNo]->getType();
395  if (ThisType != AdjustedThisPtr->getType())
396  AdjustedThisPtr = Builder.CreateBitCast(AdjustedThisPtr, ThisType);
397  Args[ThisArgNo] = AdjustedThisPtr;
398  } else {
399  assert(ThisAI.isInAlloca() && "this is passed directly or inalloca");
400  Address ThisAddr = GetAddrOfLocalVar(CXXABIThisDecl);
401  llvm::Type *ThisType = ThisAddr.getElementType();
402  if (ThisType != AdjustedThisPtr->getType())
403  AdjustedThisPtr = Builder.CreateBitCast(AdjustedThisPtr, ThisType);
404  Builder.CreateStore(AdjustedThisPtr, ThisAddr);
405  }
406 
407  // Emit the musttail call manually. Even if the prologue pushed cleanups, we
408  // don't actually want to run them.
409  llvm::CallInst *Call = Builder.CreateCall(CalleePtr, Args);
410  Call->setTailCallKind(llvm::CallInst::TCK_MustTail);
411 
412  // Apply the standard set of call attributes.
413  unsigned CallingConv;
414  llvm::AttributeList Attrs;
415  CGM.ConstructAttributeList(CalleePtr->getName(), *CurFnInfo, MD, Attrs,
416  CallingConv, /*AttrOnCallSite=*/true);
417  Call->setAttributes(Attrs);
418  Call->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
419 
420  if (Call->getType()->isVoidTy())
421  Builder.CreateRetVoid();
422  else
423  Builder.CreateRet(Call);
424 
425  // Finish the function to maintain CodeGenFunction invariants.
426  // FIXME: Don't emit unreachable code.
427  EmitBlock(createBasicBlock());
428  FinishFunction();
429 }
430 
431 void CodeGenFunction::generateThunk(llvm::Function *Fn,
432  const CGFunctionInfo &FnInfo, GlobalDecl GD,
433  const ThunkInfo &Thunk,
434  bool IsUnprototyped) {
435  StartThunk(Fn, GD, FnInfo, IsUnprototyped);
436  // Create a scope with an artificial location for the body of this function.
437  auto AL = ApplyDebugLocation::CreateArtificial(*this);
438 
439  // Get our callee. Use a placeholder type if this method is unprototyped so
440  // that CodeGenModule doesn't try to set attributes.
441  llvm::Type *Ty;
442  if (IsUnprototyped)
443  Ty = llvm::StructType::get(getLLVMContext());
444  else
445  Ty = CGM.getTypes().GetFunctionType(FnInfo);
446 
447  llvm::Constant *Callee = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
448 
449  // Fix up the function type for an unprototyped musttail call.
450  if (IsUnprototyped)
451  Callee = llvm::ConstantExpr::getBitCast(Callee, Fn->getType());
452 
453  // Make the call and return the result.
454  EmitCallAndReturnForThunk(Callee, &Thunk, IsUnprototyped);
455 }
456 
458  bool IsUnprototyped, bool ForVTable) {
459  // Always emit thunks in the MS C++ ABI. We cannot rely on other TUs to
460  // provide thunks for us.
461  if (CGM.getTarget().getCXXABI().isMicrosoft())
462  return true;
463 
464  // In the Itanium C++ ABI, vtable thunks are provided by TUs that provide
465  // definitions of the main method. Therefore, emitting thunks with the vtable
466  // is purely an optimization. Emit the thunk if optimizations are enabled and
467  // all of the parameter types are complete.
468  if (ForVTable)
469  return CGM.getCodeGenOpts().OptimizationLevel && !IsUnprototyped;
470 
471  // Always emit thunks along with the method definition.
472  return true;
473 }
474 
475 llvm::Constant *CodeGenVTables::maybeEmitThunk(GlobalDecl GD,
476  const ThunkInfo &TI,
477  bool ForVTable) {
478  const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
479 
480  // First, get a declaration. Compute the mangled name. Don't worry about
481  // getting the function prototype right, since we may only need this
482  // declaration to fill in a vtable slot.
483  SmallString<256> Name;
484  MangleContext &MCtx = CGM.getCXXABI().getMangleContext();
485  llvm::raw_svector_ostream Out(Name);
486  if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD))
487  MCtx.mangleCXXDtorThunk(DD, GD.getDtorType(), TI.This, Out);
488  else
489  MCtx.mangleThunk(MD, TI, Out);
490  llvm::Type *ThunkVTableTy = CGM.getTypes().GetFunctionTypeForVTable(GD);
491  llvm::Constant *Thunk = CGM.GetAddrOfThunk(Name, ThunkVTableTy, GD);
492 
493  // If we don't need to emit a definition, return this declaration as is.
494  bool IsUnprototyped = !CGM.getTypes().isFuncTypeConvertible(
495  MD->getType()->castAs<FunctionType>());
496  if (!shouldEmitVTableThunk(CGM, MD, IsUnprototyped, ForVTable))
497  return Thunk;
498 
499  // Arrange a function prototype appropriate for a function definition. In some
500  // cases in the MS ABI, we may need to build an unprototyped musttail thunk.
501  const CGFunctionInfo &FnInfo =
502  IsUnprototyped ? CGM.getTypes().arrangeUnprototypedMustTailThunk(MD)
504  llvm::FunctionType *ThunkFnTy = CGM.getTypes().GetFunctionType(FnInfo);
505 
506  // If the type of the underlying GlobalValue is wrong, we'll have to replace
507  // it. It should be a declaration.
508  llvm::Function *ThunkFn = cast<llvm::Function>(Thunk->stripPointerCasts());
509  if (ThunkFn->getFunctionType() != ThunkFnTy) {
510  llvm::GlobalValue *OldThunkFn = ThunkFn;
511 
512  assert(OldThunkFn->isDeclaration() && "Shouldn't replace non-declaration");
513 
514  // Remove the name from the old thunk function and get a new thunk.
515  OldThunkFn->setName(StringRef());
517  Name.str(), &CGM.getModule());
518  CGM.SetLLVMFunctionAttributes(MD, FnInfo, ThunkFn);
519 
520  // If needed, replace the old thunk with a bitcast.
521  if (!OldThunkFn->use_empty()) {
522  llvm::Constant *NewPtrForOldDecl =
523  llvm::ConstantExpr::getBitCast(ThunkFn, OldThunkFn->getType());
524  OldThunkFn->replaceAllUsesWith(NewPtrForOldDecl);
525  }
526 
527  // Remove the old thunk.
528  OldThunkFn->eraseFromParent();
529  }
530 
531  bool ABIHasKeyFunctions = CGM.getTarget().getCXXABI().hasKeyFunctions();
532  bool UseAvailableExternallyLinkage = ForVTable && ABIHasKeyFunctions;
533 
534  if (!ThunkFn->isDeclaration()) {
535  if (!ABIHasKeyFunctions || UseAvailableExternallyLinkage) {
536  // There is already a thunk emitted for this function, do nothing.
537  return ThunkFn;
538  }
539 
540  setThunkProperties(CGM, TI, ThunkFn, ForVTable, GD);
541  return ThunkFn;
542  }
543 
544  // If this will be unprototyped, add the "thunk" attribute so that LLVM knows
545  // that the return type is meaningless. These thunks can be used to call
546  // functions with differing return types, and the caller is required to cast
547  // the prototype appropriately to extract the correct value.
548  if (IsUnprototyped)
549  ThunkFn->addFnAttr("thunk");
550 
552 
553  if (!IsUnprototyped && ThunkFn->isVarArg()) {
554  // Varargs thunks are special; we can't just generate a call because
555  // we can't copy the varargs. Our implementation is rather
556  // expensive/sucky at the moment, so don't generate the thunk unless
557  // we have to.
558  // FIXME: Do something better here; GenerateVarArgsThunk is extremely ugly.
559  if (UseAvailableExternallyLinkage)
560  return ThunkFn;
561  ThunkFn = CodeGenFunction(CGM).GenerateVarArgsThunk(ThunkFn, FnInfo, GD,
562  TI);
563  } else {
564  // Normal thunk body generation.
565  CodeGenFunction(CGM).generateThunk(ThunkFn, FnInfo, GD, TI, IsUnprototyped);
566  }
567 
568  setThunkProperties(CGM, TI, ThunkFn, ForVTable, GD);
569  return ThunkFn;
570 }
571 
573  const CXXMethodDecl *MD =
574  cast<CXXMethodDecl>(GD.getDecl())->getCanonicalDecl();
575 
576  // We don't need to generate thunks for the base destructor.
577  if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
578  return;
579 
580  const VTableContextBase::ThunkInfoVectorTy *ThunkInfoVector =
581  VTContext->getThunkInfo(GD);
582 
583  if (!ThunkInfoVector)
584  return;
585 
586  for (const ThunkInfo& Thunk : *ThunkInfoVector)
587  maybeEmitThunk(GD, Thunk, /*ForVTable=*/false);
588 }
589 
590 void CodeGenVTables::addVTableComponent(
591  ConstantArrayBuilder &builder, const VTableLayout &layout,
592  unsigned idx, llvm::Constant *rtti, unsigned &nextVTableThunkIndex) {
593  auto &component = layout.vtable_components()[idx];
594 
595  auto addOffsetConstant = [&](CharUnits offset) {
596  builder.add(llvm::ConstantExpr::getIntToPtr(
597  llvm::ConstantInt::get(CGM.PtrDiffTy, offset.getQuantity()),
598  CGM.Int8PtrTy));
599  };
600 
601  switch (component.getKind()) {
603  return addOffsetConstant(component.getVCallOffset());
604 
606  return addOffsetConstant(component.getVBaseOffset());
607 
609  return addOffsetConstant(component.getOffsetToTop());
610 
612  return builder.add(llvm::ConstantExpr::getBitCast(rtti, CGM.Int8PtrTy));
613 
617  GlobalDecl GD;
618 
619  // Get the right global decl.
620  switch (component.getKind()) {
621  default:
622  llvm_unreachable("Unexpected vtable component kind");
624  GD = component.getFunctionDecl();
625  break;
627  GD = GlobalDecl(component.getDestructorDecl(), Dtor_Complete);
628  break;
630  GD = GlobalDecl(component.getDestructorDecl(), Dtor_Deleting);
631  break;
632  }
633 
634  if (CGM.getLangOpts().CUDA) {
635  // Emit NULL for methods we can't codegen on this
636  // side. Otherwise we'd end up with vtable with unresolved
637  // references.
638  const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
639  // OK on device side: functions w/ __device__ attribute
640  // OK on host side: anything except __device__-only functions.
641  bool CanEmitMethod =
642  CGM.getLangOpts().CUDAIsDevice
643  ? MD->hasAttr<CUDADeviceAttr>()
644  : (MD->hasAttr<CUDAHostAttr>() || !MD->hasAttr<CUDADeviceAttr>());
645  if (!CanEmitMethod)
646  return builder.addNullPointer(CGM.Int8PtrTy);
647  // Method is acceptable, continue processing as usual.
648  }
649 
650  auto getSpecialVirtualFn = [&](StringRef name) {
651  llvm::FunctionType *fnTy =
652  llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
653  llvm::Constant *fn = CGM.CreateRuntimeFunction(fnTy, name);
654  if (auto f = dyn_cast<llvm::Function>(fn))
655  f->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
656  return llvm::ConstantExpr::getBitCast(fn, CGM.Int8PtrTy);
657  };
658 
659  llvm::Constant *fnPtr;
660 
661  // Pure virtual member functions.
662  if (cast<CXXMethodDecl>(GD.getDecl())->isPure()) {
663  if (!PureVirtualFn)
664  PureVirtualFn =
665  getSpecialVirtualFn(CGM.getCXXABI().GetPureVirtualCallName());
666  fnPtr = PureVirtualFn;
667 
668  // Deleted virtual member functions.
669  } else if (cast<CXXMethodDecl>(GD.getDecl())->isDeleted()) {
670  if (!DeletedVirtualFn)
671  DeletedVirtualFn =
672  getSpecialVirtualFn(CGM.getCXXABI().GetDeletedVirtualCallName());
673  fnPtr = DeletedVirtualFn;
674 
675  // Thunks.
676  } else if (nextVTableThunkIndex < layout.vtable_thunks().size() &&
677  layout.vtable_thunks()[nextVTableThunkIndex].first == idx) {
678  auto &thunkInfo = layout.vtable_thunks()[nextVTableThunkIndex].second;
679 
680  nextVTableThunkIndex++;
681  fnPtr = maybeEmitThunk(GD, thunkInfo, /*ForVTable=*/true);
682 
683  // Otherwise we can use the method definition directly.
684  } else {
685  llvm::Type *fnTy = CGM.getTypes().GetFunctionTypeForVTable(GD);
686  fnPtr = CGM.GetAddrOfFunction(GD, fnTy, /*ForVTable=*/true);
687  }
688 
689  fnPtr = llvm::ConstantExpr::getBitCast(fnPtr, CGM.Int8PtrTy);
690  builder.add(fnPtr);
691  return;
692  }
693 
695  return builder.addNullPointer(CGM.Int8PtrTy);
696  }
697 
698  llvm_unreachable("Unexpected vtable component kind");
699 }
700 
703  for (unsigned i = 0, e = layout.getNumVTables(); i != e; ++i) {
704  tys.push_back(llvm::ArrayType::get(CGM.Int8PtrTy, layout.getVTableSize(i)));
705  }
706 
707  return llvm::StructType::get(CGM.getLLVMContext(), tys);
708 }
709 
711  const VTableLayout &layout,
712  llvm::Constant *rtti) {
713  unsigned nextVTableThunkIndex = 0;
714  for (unsigned i = 0, e = layout.getNumVTables(); i != e; ++i) {
715  auto vtableElem = builder.beginArray(CGM.Int8PtrTy);
716  size_t thisIndex = layout.getVTableOffset(i);
717  size_t nextIndex = thisIndex + layout.getVTableSize(i);
718  for (unsigned i = thisIndex; i != nextIndex; ++i) {
719  addVTableComponent(vtableElem, layout, i, rtti, nextVTableThunkIndex);
720  }
721  vtableElem.finishAndAddTo(builder);
722  }
723 }
724 
725 llvm::GlobalVariable *
727  const BaseSubobject &Base,
728  bool BaseIsVirtual,
729  llvm::GlobalVariable::LinkageTypes Linkage,
730  VTableAddressPointsMapTy& AddressPoints) {
731  if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
732  DI->completeClassData(Base.getBase());
733 
734  std::unique_ptr<VTableLayout> VTLayout(
735  getItaniumVTableContext().createConstructionVTableLayout(
736  Base.getBase(), Base.getBaseOffset(), BaseIsVirtual, RD));
737 
738  // Add the address points.
739  AddressPoints = VTLayout->getAddressPoints();
740 
741  // Get the mangled construction vtable name.
742  SmallString<256> OutName;
743  llvm::raw_svector_ostream Out(OutName);
744  cast<ItaniumMangleContext>(CGM.getCXXABI().getMangleContext())
745  .mangleCXXCtorVTable(RD, Base.getBaseOffset().getQuantity(),
746  Base.getBase(), Out);
747  StringRef Name = OutName.str();
748 
749  llvm::Type *VTType = getVTableType(*VTLayout);
750 
751  // Construction vtable symbols are not part of the Itanium ABI, so we cannot
752  // guarantee that they actually will be available externally. Instead, when
753  // emitting an available_externally VTT, we provide references to an internal
754  // linkage construction vtable. The ABI only requires complete-object vtables
755  // to be the same for all instances of a type, not construction vtables.
756  if (Linkage == llvm::GlobalVariable::AvailableExternallyLinkage)
758 
759  // Create the variable that will hold the construction vtable.
760  llvm::GlobalVariable *VTable =
761  CGM.CreateOrReplaceCXXRuntimeVariable(Name, VTType, Linkage);
762  CGM.setGVProperties(VTable, RD);
763 
764  // V-tables are always unnamed_addr.
765  VTable->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
766 
767  llvm::Constant *RTTI = CGM.GetAddrOfRTTIDescriptor(
768  CGM.getContext().getTagDeclType(Base.getBase()));
769 
770  // Create and set the initializer.
771  ConstantInitBuilder builder(CGM);
772  auto components = builder.beginStruct();
773  createVTableInitializer(components, *VTLayout, RTTI);
774  components.finishAndSetAsInitializer(VTable);
775 
776  CGM.EmitVTableTypeMetadata(VTable, *VTLayout.get());
777 
778  return VTable;
779 }
780 
782  const CXXRecordDecl *RD) {
783  return CGM.getCodeGenOpts().OptimizationLevel > 0 &&
785 }
786 
787 /// Compute the required linkage of the vtable for the given class.
788 ///
789 /// Note that we only call this at the end of the translation unit.
790 llvm::GlobalVariable::LinkageTypes
792  if (!RD->isExternallyVisible())
794 
795  // We're at the end of the translation unit, so the current key
796  // function is fully correct.
797  const CXXMethodDecl *keyFunction = Context.getCurrentKeyFunction(RD);
798  if (keyFunction && !RD->hasAttr<DLLImportAttr>()) {
799  // If this class has a key function, use that to determine the
800  // linkage of the vtable.
801  const FunctionDecl *def = nullptr;
802  if (keyFunction->hasBody(def))
803  keyFunction = cast<CXXMethodDecl>(def);
804 
805  switch (keyFunction->getTemplateSpecializationKind()) {
806  case TSK_Undeclared:
808  assert((def || CodeGenOpts.OptimizationLevel > 0 ||
809  CodeGenOpts.getDebugInfo() != codegenoptions::NoDebugInfo) &&
810  "Shouldn't query vtable linkage without key function, "
811  "optimizations, or debug info");
812  if (!def && CodeGenOpts.OptimizationLevel > 0)
813  return llvm::GlobalVariable::AvailableExternallyLinkage;
814 
815  if (keyFunction->isInlined())
816  return !Context.getLangOpts().AppleKext ?
817  llvm::GlobalVariable::LinkOnceODRLinkage :
819 
821 
823  return !Context.getLangOpts().AppleKext ?
824  llvm::GlobalVariable::LinkOnceODRLinkage :
826 
828  return !Context.getLangOpts().AppleKext ?
829  llvm::GlobalVariable::WeakODRLinkage :
831 
833  llvm_unreachable("Should not have been asked to emit this");
834  }
835  }
836 
837  // -fapple-kext mode does not support weak linkage, so we must use
838  // internal linkage.
839  if (Context.getLangOpts().AppleKext)
841 
842  llvm::GlobalVariable::LinkageTypes DiscardableODRLinkage =
843  llvm::GlobalValue::LinkOnceODRLinkage;
844  llvm::GlobalVariable::LinkageTypes NonDiscardableODRLinkage =
845  llvm::GlobalValue::WeakODRLinkage;
846  if (RD->hasAttr<DLLExportAttr>()) {
847  // Cannot discard exported vtables.
848  DiscardableODRLinkage = NonDiscardableODRLinkage;
849  } else if (RD->hasAttr<DLLImportAttr>()) {
850  // Imported vtables are available externally.
851  DiscardableODRLinkage = llvm::GlobalVariable::AvailableExternallyLinkage;
852  NonDiscardableODRLinkage = llvm::GlobalVariable::AvailableExternallyLinkage;
853  }
854 
855  switch (RD->getTemplateSpecializationKind()) {
856  case TSK_Undeclared:
859  return DiscardableODRLinkage;
860 
862  // Explicit instantiations in MSVC do not provide vtables, so we must emit
863  // our own.
864  if (getTarget().getCXXABI().isMicrosoft())
865  return DiscardableODRLinkage;
866  return shouldEmitAvailableExternallyVTable(*this, RD)
867  ? llvm::GlobalVariable::AvailableExternallyLinkage
869 
871  return NonDiscardableODRLinkage;
872  }
873 
874  llvm_unreachable("Invalid TemplateSpecializationKind!");
875 }
876 
877 /// This is a callback from Sema to tell us that a particular vtable is
878 /// required to be emitted in this translation unit.
879 ///
880 /// This is only called for vtables that _must_ be emitted (mainly due to key
881 /// functions). For weak vtables, CodeGen tracks when they are needed and
882 /// emits them as-needed.
884  VTables.GenerateClassData(theClass);
885 }
886 
887 void
889  if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
890  DI->completeClassData(RD);
891 
892  if (RD->getNumVBases())
894 
895  CGM.getCXXABI().emitVTableDefinitions(*this, RD);
896 }
897 
898 /// At this point in the translation unit, does it appear that can we
899 /// rely on the vtable being defined elsewhere in the program?
900 ///
901 /// The response is really only definitive when called at the end of
902 /// the translation unit.
903 ///
904 /// The only semantic restriction here is that the object file should
905 /// not contain a vtable definition when that vtable is defined
906 /// strongly elsewhere. Otherwise, we'd just like to avoid emitting
907 /// vtables when unnecessary.
909  assert(RD->isDynamicClass() && "Non-dynamic classes have no VTable.");
910 
911  // We always synthesize vtables if they are needed in the MS ABI. MSVC doesn't
912  // emit them even if there is an explicit template instantiation.
913  if (CGM.getTarget().getCXXABI().isMicrosoft())
914  return false;
915 
916  // If we have an explicit instantiation declaration (and not a
917  // definition), the vtable is defined elsewhere.
920  return true;
921 
922  // Otherwise, if the class is an instantiated template, the
923  // vtable must be defined here.
924  if (TSK == TSK_ImplicitInstantiation ||
926  return false;
927 
928  // Otherwise, if the class doesn't have a key function (possibly
929  // anymore), the vtable must be defined here.
930  const CXXMethodDecl *keyFunction = CGM.getContext().getCurrentKeyFunction(RD);
931  if (!keyFunction)
932  return false;
933 
934  // Otherwise, if we don't have a definition of the key function, the
935  // vtable must be defined somewhere else.
936  return !keyFunction->hasBody();
937 }
938 
939 /// Given that we're currently at the end of the translation unit, and
940 /// we've emitted a reference to the vtable for this class, should
941 /// we define that vtable?
943  const CXXRecordDecl *RD) {
944  // If vtable is internal then it has to be done.
945  if (!CGM.getVTables().isVTableExternal(RD))
946  return true;
947 
948  // If it's external then maybe we will need it as available_externally.
949  return shouldEmitAvailableExternallyVTable(CGM, RD);
950 }
951 
952 /// Given that at some point we emitted a reference to one or more
953 /// vtables, and that we are now at the end of the translation unit,
954 /// decide whether we should emit them.
955 void CodeGenModule::EmitDeferredVTables() {
956 #ifndef NDEBUG
957  // Remember the size of DeferredVTables, because we're going to assume
958  // that this entire operation doesn't modify it.
959  size_t savedSize = DeferredVTables.size();
960 #endif
961 
962  for (const CXXRecordDecl *RD : DeferredVTables)
964  VTables.GenerateClassData(RD);
965  else if (shouldOpportunisticallyEmitVTables())
966  OpportunisticVTables.push_back(RD);
967 
968  assert(savedSize == DeferredVTables.size() &&
969  "deferred extra vtables during vtable emission?");
970  DeferredVTables.clear();
971 }
972 
975  if (!isExternallyVisible(LV.getLinkage()))
976  return true;
977 
978  if (RD->hasAttr<LTOVisibilityPublicAttr>() || RD->hasAttr<UuidAttr>())
979  return false;
980 
981  if (getTriple().isOSBinFormatCOFF()) {
982  if (RD->hasAttr<DLLExportAttr>() || RD->hasAttr<DLLImportAttr>())
983  return false;
984  } else {
985  if (LV.getVisibility() != HiddenVisibility)
986  return false;
987  }
988 
989  if (getCodeGenOpts().LTOVisibilityPublicStd) {
990  const DeclContext *DC = RD;
991  while (1) {
992  auto *D = cast<Decl>(DC);
993  DC = DC->getParent();
994  if (isa<TranslationUnitDecl>(DC->getRedeclContext())) {
995  if (auto *ND = dyn_cast<NamespaceDecl>(D))
996  if (const IdentifierInfo *II = ND->getIdentifier())
997  if (II->isStr("std") || II->isStr("stdext"))
998  return false;
999  break;
1000  }
1001  }
1002  }
1003 
1004  return true;
1005 }
1006 
1007 void CodeGenModule::EmitVTableTypeMetadata(llvm::GlobalVariable *VTable,
1008  const VTableLayout &VTLayout) {
1009  if (!getCodeGenOpts().LTOUnit)
1010  return;
1011 
1012  CharUnits PointerWidth =
1013  Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
1014 
1015  typedef std::pair<const CXXRecordDecl *, unsigned> AddressPoint;
1016  std::vector<AddressPoint> AddressPoints;
1017  for (auto &&AP : VTLayout.getAddressPoints())
1018  AddressPoints.push_back(std::make_pair(
1019  AP.first.getBase(), VTLayout.getVTableOffset(AP.second.VTableIndex) +
1020  AP.second.AddressPointIndex));
1021 
1022  // Sort the address points for determinism.
1023  llvm::sort(AddressPoints.begin(), AddressPoints.end(),
1024  [this](const AddressPoint &AP1, const AddressPoint &AP2) {
1025  if (&AP1 == &AP2)
1026  return false;
1027 
1028  std::string S1;
1029  llvm::raw_string_ostream O1(S1);
1030  getCXXABI().getMangleContext().mangleTypeName(
1031  QualType(AP1.first->getTypeForDecl(), 0), O1);
1032  O1.flush();
1033 
1034  std::string S2;
1035  llvm::raw_string_ostream O2(S2);
1036  getCXXABI().getMangleContext().mangleTypeName(
1037  QualType(AP2.first->getTypeForDecl(), 0), O2);
1038  O2.flush();
1039 
1040  if (S1 < S2)
1041  return true;
1042  if (S1 != S2)
1043  return false;
1044 
1045  return AP1.second < AP2.second;
1046  });
1047 
1048  ArrayRef<VTableComponent> Comps = VTLayout.vtable_components();
1049  for (auto AP : AddressPoints) {
1050  // Create type metadata for the address point.
1051  AddVTableTypeMetadata(VTable, PointerWidth * AP.second, AP.first);
1052 
1053  // The class associated with each address point could also potentially be
1054  // used for indirect calls via a member function pointer, so we need to
1055  // annotate the address of each function pointer with the appropriate member
1056  // function pointer type.
1057  for (unsigned I = 0; I != Comps.size(); ++I) {
1058  if (Comps[I].getKind() != VTableComponent::CK_FunctionPointer)
1059  continue;
1060  llvm::Metadata *MD = CreateMetadataIdentifierForVirtualMemPtrType(
1061  Context.getMemberPointerType(
1062  Comps[I].getFunctionDecl()->getType(),
1063  Context.getRecordType(AP.first).getTypePtr()));
1064  VTable->addTypeMetadata((PointerWidth * I).getQuantity(), MD);
1065  }
1066  }
1067 }
size_t getNumVTables() const
ReturnValueSlot - Contains the address where the return value of a function can be stored...
Definition: CGCall.h:361
static const Decl * getCanonicalDecl(const Decl *D)
Represents a function declaration or definition.
Definition: Decl.h:1714
External linkage, which indicates that the entity can be referred to from other translation units...
Definition: Linkage.h:60
CanQualType VoidPtrTy
Definition: ASTContext.h:1026
A (possibly-)qualified type.
Definition: Type.h:655
bool ReturnTypeUsesSRet(const CGFunctionInfo &FI)
Return true iff the given type uses &#39;sret&#39; when used as a return type.
Definition: CGCall.cpp:1500
const CodeGenOptions & getCodeGenOpts() const
const AddressPointsMapTy & getAddressPoints() const
virtual void EmitReturnFromThunk(CodeGenFunction &CGF, RValue RV, QualType ResultType)
Definition: CGCXXABI.cpp:163
llvm::LLVMContext & getLLVMContext()
CXXDtorType getDtorType() const
Definition: GlobalDecl.h:71
virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, FunctionArgList &Params)=0
Insert any ABI-specific implicit parameters into the parameter list for a function.
The standard implementation of ConstantInitBuilder used in Clang.
CharUnits getClassPointerAlignment(const CXXRecordDecl *CD)
Returns the assumed alignment of an opaque pointer to the given class.
Definition: CGClass.cpp:36
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3205
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:491
unsigned getNumVBases() const
Retrieves the number of virtual base classes of this class.
Definition: DeclCXX.h:838
bool isEmpty() const
Definition: ABI.h:87
virtual const ThunkInfoVectorTy * getThunkInfo(GlobalDecl GD)
virtual llvm::Value * performThisAdjustment(CodeGenFunction &CGF, Address This, const ThisAdjustment &TA)=0
void setFunctionLinkage(GlobalDecl GD, llvm::Function *F)
virtual StringRef GetDeletedVirtualCallName()=0
Gets the deleted virtual member call name.
const TargetInfo & getTargetInfo() const
Definition: ASTContext.h:673
llvm::Function * GenerateVarArgsThunk(llvm::Function *Fn, const CGFunctionInfo &FnInfo, GlobalDecl GD, const ThunkInfo &Thunk)
Definition: CGVTables.cpp:157
bool isFuncTypeConvertible(const FunctionType *FT)
isFuncTypeConvertible - Utility to check whether a function type can be converted to an LLVM type (i...
bool HasHiddenLTOVisibility(const CXXRecordDecl *RD)
Returns whether the given record has hidden LTO visibility and therefore may participate in (single-m...
Definition: CGVTables.cpp:973
void StartThunk(llvm::Function *Fn, GlobalDecl GD, const CGFunctionInfo &FnInfo, bool IsUnprototyped)
Definition: CGVTables.cpp:225
Objects with "hidden" visibility are not seen by the dynamic linker.
Definition: Visibility.h:37
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6519
Visibility getVisibility() const
Definition: Visibility.h:85
CGDebugInfo * getModuleDebugInfo()
This class gathers all debug information during compilation and is responsible for emitting to llvm g...
Definition: CGDebugInfo.h:54
QualType getMemberPointerType(QualType T, const Type *Cls) const
Return the uniqued reference to the type for a member pointer to the specified type in the specified ...
llvm::Value * getPointer() const
Definition: Address.h:38
Represents a parameter to a function.
Definition: Decl.h:1533
Linkage
Describes the different kinds of linkage (C++ [basic.link], C99 6.2.2) that an entity may have...
Definition: Linkage.h:24
void add(RValue rvalue, QualType type)
Definition: CGCall.h:285
CharUnits getBaseOffset() const
getBaseOffset - Returns the base class offset.
Definition: BaseSubobject.h:46
uint64_t getPointerWidth(unsigned AddrSpace) const
Return the width of pointers on this target, for the specified address space.
Definition: TargetInfo.h:340
One of these records is kept for each identifier that is lexed.
TargetCXXABI getCXXABI() const
Get the C++ ABI currently in use.
Definition: TargetInfo.h:1010
void generateThunk(llvm::Function *Fn, const CGFunctionInfo &FnInfo, GlobalDecl GD, const ThunkInfo &Thunk, bool IsUnprototyped)
Generate a thunk for the given method.
Definition: CGVTables.cpp:431
Indirect - Pass the argument indirectly via a hidden pointer with the specified alignment (0 indicate...
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
static bool shouldEmitAvailableExternallyVTable(const CodeGenModule &CGM, const CXXRecordDecl *RD)
Definition: CGVTables.cpp:781
bool isReferenceType() const
Definition: Type.h:6118
static void resolveTopLevelMetadata(llvm::Function *Fn, llvm::ValueToValueMapTy &VMap)
This function clones a function&#39;s DISubprogram node and enters it into a value map with the intent th...
Definition: CGVTables.cpp:118
llvm::Type * getVTableType(const VTableLayout &layout)
Returns the type of a vtable with the given layout.
Definition: CGVTables.cpp:701
The this pointer adjustment as well as an optional return adjustment for a thunk. ...
Definition: ABI.h:179
static ApplyDebugLocation CreateArtificial(CodeGenFunction &CGF)
Apply TemporaryLocation if it is valid.
Definition: CGDebugInfo.h:673
ArrayRef< ParmVarDecl * > parameters() const
Definition: Decl.h:2222
virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF)=0
Emit the ABI-specific prolog for the function.
ArrayRef< VTableComponent > vtable_components() const
QualType getThisType(ASTContext &C) const
Returns the type of the this pointer.
Definition: DeclCXX.cpp:2138
virtual void emitVTableDefinitions(CodeGenVTables &CGVT, const CXXRecordDecl *RD)=0
Emits the VTable definitions required for the given record type.
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
Deleting dtor.
Definition: ABI.h:35
virtual bool hasMostDerivedReturn(GlobalDecl GD) const
Definition: CGCXXABI.h:109
bool isVolatileQualified() const
Determine whether this type is volatile-qualified.
Definition: Type.h:5952
void ConstructAttributeList(StringRef Name, const CGFunctionInfo &Info, CGCalleeInfo CalleeInfo, llvm::AttributeList &Attrs, unsigned &CallingConv, bool AttrOnCallSite)
Get the LLVM attributes and calling convention to use for a particular function type.
Definition: CGCall.cpp:1814
ABIArgInfo - Helper class to encapsulate information about how a specific C type should be passed to ...
virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const =0
Determine whether it&#39;s possible to emit a vtable for RD, even though we do not know that the vtable h...
const Type * getTypePtr() const
Retrieves a pointer to the underlying (unqualified) type.
Definition: Type.h:5882
llvm::BasicBlock * createBasicBlock(const Twine &name="", llvm::Function *parent=nullptr, llvm::BasicBlock *before=nullptr)
createBasicBlock - Create an LLVM basic block.
ItaniumVTableContext & getItaniumVTableContext()
Definition: CGVTables.h:79
static bool shouldEmitVTableThunk(CodeGenModule &CGM, const CXXMethodDecl *MD, bool IsUnprototyped, bool ForVTable)
Definition: CGVTables.cpp:457
const CGFunctionInfo & arrangeGlobalDeclaration(GlobalDecl GD)
Definition: CGCall.cpp:510
param_iterator param_begin()
Definition: Decl.h:2234
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.
bool hasAttr() const
Definition: DeclBase.h:536
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1621
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3426
bool isDynamicClass() const
Definition: DeclCXX.h:789
ArrayBuilder beginArray(llvm::Type *eltTy=nullptr)
TemplateSpecializationKind getTemplateSpecializationKind() const
Determine whether this particular class is a specialization or instantiation of a class template or m...
Definition: DeclCXX.cpp:1593
RValue - This trivial value class is used to represent the result of an expression that is evaluated...
Definition: CGValue.h:39
QuantityType getQuantity() const
getQuantity - Get the raw integer representation of this quantity.
Definition: CharUnits.h:179
bool isVTableExternal(const CXXRecordDecl *RD)
At this point in the translation unit, does it appear that can we rely on the vtable being defined el...
Definition: CGVTables.cpp:908
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
bool hasKeyFunctions() const
Does this ABI use key functions? If so, class data such as the vtable is emitted with strong linkage ...
Definition: TargetCXXABI.h:227
void SetLLVMFunctionAttributes(const Decl *D, const CGFunctionInfo &Info, llvm::Function *F)
Set the LLVM function attributes (sext, zext, etc).
static void setThunkProperties(CodeGenModule &CGM, const ThunkInfo &Thunk, llvm::Function *ThunkFn, bool ForVTable, GlobalDecl GD)
Definition: CGVTables.cpp:40
static bool similar(const ABIArgInfo &infoL, CanQualType typeL, const ABIArgInfo &infoR, CanQualType typeR)
Definition: CGVTables.cpp:60
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6582
static CGCallee forDirect(llvm::Constant *functionPtr, const CGCalleeInfo &abstractInfo=CGCalleeInfo())
Definition: CGCall.h:134
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2698
virtual bool exportThunk()=0
QualType getTagDeclType(const TagDecl *Decl) const
Return the unique reference to the type for the specified TagDecl (struct/union/class/enum) decl...
virtual StringRef GetPureVirtualCallName()=0
Gets the pure virtual member call function.
Linkage getLinkage() const
Definition: Visibility.h:84
const CXXRecordDecl * getBase() const
getBase - Returns the base class declaration.
Definition: BaseSubobject.h:43
void EmitCallAndReturnForThunk(llvm::Constant *Callee, const ThunkInfo *Thunk, bool IsUnprototyped)
Definition: CGVTables.cpp:282
bool hasBody(const FunctionDecl *&Definition) const
Returns true if the function has a body.
Definition: Decl.cpp:2626
Base object dtor.
Definition: ABI.h:37
const CGFunctionInfo & arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD)
Arrange a thunk that takes &#39;this&#39; as the first parameter followed by varargs.
Definition: CGCall.cpp:529
DeclContext * getParent()
getParent - Returns the containing DeclContext.
Definition: DeclBase.h:1341
bool isExternallyVisible(Linkage L)
Definition: Linkage.h:86
QualType getRecordType(const RecordDecl *Decl) const
const TargetInfo & getTarget() const
This template specialization was implicitly instantiated from a template.
Definition: Specifiers.h:152
const LangOptions & getLangOpts() const
ASTContext & getContext() const
virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, GlobalDecl GD, CallArgList &CallArgs)
Definition: CGCXXABI.h:435
CallingConv
CallingConv - Specifies the calling convention that a function uses.
Definition: Specifiers.h:236
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:35
llvm::GlobalVariable * CreateOrReplaceCXXRuntimeVariable(StringRef Name, llvm::Type *Ty, llvm::GlobalValue::LinkageTypes Linkage)
Will return a global variable of the given type.
The l-value was considered opaque, so the alignment was determined from a type.
ArrayRef< VTableThunkTy > vtable_thunks() const
virtual void mangleCXXDtorThunk(const CXXDestructorDecl *DD, CXXDtorType Type, const ThisAdjustment &ThisAdjustment, raw_ostream &)=0
llvm::Constant * GetAddrOfThunk(StringRef Name, llvm::Type *FnTy, GlobalDecl GD)
Get the address of the thunk for the given global decl.
Definition: CGVTables.cpp:34
Encodes a location in the source.
QualType getReturnType() const
Definition: Type.h:3359
void setGVProperties(llvm::GlobalValue *GV, GlobalDecl GD) const
Set visibility, dllimport/dllexport and dso_local.
const Decl * getDecl() const
Definition: GlobalDecl.h:64
MangleContext - Context for tracking state which persists across multiple calls to the C++ name mangl...
Definition: Mangle.h:43
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:2043
llvm::Constant * GetAddrOfRTTIDescriptor(QualType Ty, bool ForEH=false)
Get the address of the RTTI descriptor for the given type.
CodeGenVTables(CodeGenModule &CGM)
Definition: CGVTables.cpp:31
CanQualType VoidTy
Definition: ASTContext.h:998
void createVTableInitializer(ConstantStructBuilder &builder, const VTableLayout &layout, llvm::Constant *rtti)
Add vtable components for the given vtable layout to the given global initializer.
Definition: CGVTables.cpp:710
An aligned address.
Definition: Address.h:25
void SetLLVMFunctionAttributesForDefinition(const Decl *D, llvm::Function *F)
Set the LLVM function attributes which only apply to a function definition.
virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD)=0
Emit any tables needed to implement virtual inheritance.
All available information about a concrete callee.
Definition: CGCall.h:67
MangleContext & getMangleContext()
Gets the mangle context.
Definition: CGCXXABI.h:97
This template specialization was instantiated from a template due to an explicit instantiation defini...
Definition: Specifiers.h:164
This template specialization was formed from a template-id but has not yet been declared, defined, or instantiated.
Definition: Specifiers.h:149
Complete object dtor.
Definition: ABI.h:36
llvm::GlobalVariable * GenerateConstructionVTable(const CXXRecordDecl *RD, const BaseSubobject &Base, bool BaseIsVirtual, llvm::GlobalVariable::LinkageTypes Linkage, VTableAddressPointsMapTy &AddressPoints)
GenerateConstructionVTable - Generate a construction vtable for the given base subobject.
Definition: CGVTables.cpp:726
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
void ErrorUnsupported(const Stmt *S, const char *Type)
Print out an error that codegen doesn&#39;t support the specified stmt yet.
CGFunctionInfo - Class to encapsulate the information about a function definition.
This class organizes the cross-function state that is used while generating LLVM code.
Dataflow Directional Tag Classes.
ThisAdjustment This
The this pointer adjustment.
Definition: ABI.h:181
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1262
TemplateSpecializationKind getTemplateSpecializationKind() const
Determine what kind of template instantiation this function represents.
Definition: Decl.cpp:3483
void EmitVTableTypeMetadata(llvm::GlobalVariable *VTable, const VTableLayout &VTLayout)
Emit type metadata for the given vtable using the given layout.
Definition: CGVTables.cpp:1007
This template specialization was instantiated from a template due to an explicit instantiation declar...
Definition: Specifiers.h:160
const CXXRecordDecl * getParent() const
Returns the parent of this method declaration, which is the class in which this method is defined...
Definition: DeclCXX.h:2163
void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params)
Build a parameter variable suitable for &#39;this&#39;.
Definition: CGCXXABI.cpp:128
TemplateSpecializationKind
Describes the kind of template specialization that a particular template specialization declaration r...
Definition: Specifiers.h:146
llvm::Module & getModule() const
void EmitThunks(GlobalDecl GD)
EmitThunks - Emit the associated thunks for the given global decl.
Definition: CGVTables.cpp:572
param_iterator param_end()
Definition: Decl.h:2235
llvm::GlobalVariable::LinkageTypes getVTableLinkage(const CXXRecordDecl *RD)
Return the appropriate linkage for the vtable, VTT, and type information of the given class...
Definition: CGVTables.cpp:791
LinkageInfo getLinkageAndVisibility() const
Determines the linkage and visibility of this entity.
Definition: Decl.cpp:1070
StructBuilder beginStruct(llvm::StructType *structTy=nullptr)
This template specialization was declared or defined by an explicit specialization (C++ [temp...
Definition: Specifiers.h:156
static bool shouldEmitVTableAtEndOfTranslationUnit(CodeGenModule &CGM, const CXXRecordDecl *RD)
Given that we&#39;re currently at the end of the translation unit, and we&#39;ve emitted a reference to the v...
Definition: CGVTables.cpp:942
void GenerateClassData(const CXXRecordDecl *RD)
GenerateClassData - Generate all the class data required to be generated upon definition of a KeyFunc...
Definition: CGVTables.cpp:888
ReturnAdjustment Return
The return adjustment.
Definition: ABI.h:184
llvm::Constant * GetAddrOfFunction(GlobalDecl GD, llvm::Type *Ty=nullptr, bool ForVTable=false, bool DontDefer=false, ForDefinition_t IsForDefinition=NotForDefinition)
Return the address of the given function.
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
bool isInlined() const
Determine whether this function should be inlined, because it is either marked "inline" or "constexpr...
Definition: Decl.h:2312
llvm::Type * GetFunctionTypeForVTable(GlobalDecl GD)
GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable, given a CXXMethodDecl...
Definition: CGCall.cpp:1672
CharUnits toCharUnitsFromBits(int64_t BitSize) const
Convert a size in bits to a size in characters.
static RValue PerformReturnAdjustment(CodeGenFunction &CGF, QualType ResultType, RValue RV, const ThunkInfo &Thunk)
Definition: CGVTables.cpp:69
const CXXMethodDecl * getCurrentKeyFunction(const CXXRecordDecl *RD)
Get our current best idea for the key function of the given record decl, or nullptr if there isn&#39;t on...
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
bool isVoidType() const
Definition: Type.h:6333
virtual void mangleThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk, raw_ostream &)=0
A helper class of ConstantInitBuilder, used for building constant struct initializers.
size_t getVTableSize(size_t i) const
bool isMicrosoft() const
Is this ABI an MSVC-compatible ABI?
Definition: TargetCXXABI.h:154
A pointer to the deleting destructor.
Definition: VTableBuilder.h:43
CGCXXABI & getCXXABI() const
static Decl::Kind getKind(const Decl *D)
Definition: DeclBase.cpp:930
static RValue get(llvm::Value *V)
Definition: CGValue.h:86
static RequiredArgs forPrototypePlus(const FunctionProtoType *prototype, unsigned additional, const FunctionDecl *FD)
Compute the arguments required by the given formal prototype, given that there may be some additional...
virtual llvm::Value * performReturnAdjustment(CodeGenFunction &CGF, Address Ret, const ReturnAdjustment &RA)=0
static ApplyDebugLocation CreateEmpty(CodeGenFunction &CGF)
Set the IRBuilder to not attach debug locations.
Definition: CGDebugInfo.h:690
QualType getType() const
Definition: Decl.h:647
CodeGenVTables & getVTables()
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:260
const CGFunctionInfo & arrangeCXXMethodCall(const CallArgList &args, const FunctionProtoType *type, RequiredArgs required, unsigned numPrefixArgs)
Arrange a call to a C++ method, passing the given arguments.
Definition: CGCall.cpp:675
const LangOptions & getLangOpts() const
Definition: ASTContext.h:690
A pointer to the complete destructor.
Definition: VTableBuilder.h:40
A helper class of ConstantInitBuilder, used for building constant array initializers.
size_t getVTableOffset(size_t i) const
virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, GlobalDecl GD, bool ReturnAdjustment)=0
SourceLocation getLocation() const
Definition: DeclBase.h:417
bool isExternallyVisible() const
Definition: Decl.h:379
void EmitVTable(CXXRecordDecl *Class)
This is a callback from Sema to tell us that a particular vtable is required to be emitted in this tr...
Definition: CGVTables.cpp:883
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 EmitMustTailThunk(const CXXMethodDecl *MD, llvm::Value *AdjustedThisPtr, llvm::Value *Callee)
Emit a musttail call for a thunk with a potentially adjusted this pointer.
Definition: CGVTables.cpp:378
llvm::FunctionType * GetFunctionType(const CGFunctionInfo &Info)
GetFunctionType - Get the LLVM function type for.
Definition: CGCall.cpp:1544