1//===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This contains code dealing with C++ code generation.
11//
12//===----------------------------------------------------------------------===//
13
14// We might split this into multiple files if it gets too unwieldy
15
16#include "CodeGenFunction.h"
17#include "CodeGenModule.h"
18#include "Mangle.h"
19#include "clang/AST/ASTContext.h"
20#include "clang/AST/RecordLayout.h"
21#include "clang/AST/Decl.h"
22#include "clang/AST/DeclCXX.h"
23#include "clang/AST/DeclObjC.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/CodeGen/CodeGenOptions.h"
26#include "llvm/ADT/StringExtras.h"
27using namespace clang;
28using namespace CodeGen;
29
30/// Determines whether the given function has a trivial body that does
31/// not require any specific codegen.
32static bool HasTrivialBody(const FunctionDecl *FD) {
33 Stmt *S = FD->getBody();
34 if (!S)
35 return true;
36 if (isa<CompoundStmt>(S) && cast<CompoundStmt>(S)->body_empty())
37 return true;
38 return false;
39}
40
41/// Try to emit a base destructor as an alias to its primary
42/// base-class destructor.
43bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
44 if (!getCodeGenOpts().CXXCtorDtorAliases)
45 return true;
46
47 // If the destructor doesn't have a trivial body, we have to emit it
48 // separately.
49 if (!HasTrivialBody(D))
50 return true;
51
52 const CXXRecordDecl *Class = D->getParent();
53
54 // If we need to manipulate a VTT parameter, give up.
55 if (Class->getNumVBases()) {
56 // Extra Credit: passing extra parameters is perfectly safe
57 // in many calling conventions, so only bail out if the ctor's
58 // calling convention is nonstandard.
59 return true;
60 }
61
62 // If any fields have a non-trivial destructor, we have to emit it
63 // separately.
64 for (CXXRecordDecl::field_iterator I = Class->field_begin(),
65 E = Class->field_end(); I != E; ++I)
66 if (const RecordType *RT = (*I)->getType()->getAs<RecordType>())
67 if (!cast<CXXRecordDecl>(RT->getDecl())->hasTrivialDestructor())
68 return true;
69
70 // Try to find a unique base class with a non-trivial destructor.
71 const CXXRecordDecl *UniqueBase = 0;
72 for (CXXRecordDecl::base_class_const_iterator I = Class->bases_begin(),
73 E = Class->bases_end(); I != E; ++I) {
74
75 // We're in the base destructor, so skip virtual bases.
76 if (I->isVirtual()) continue;
77
78 // Skip base classes with trivial destructors.
79 const CXXRecordDecl *Base
80 = cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
81 if (Base->hasTrivialDestructor()) continue;
82
83 // If we've already found a base class with a non-trivial
84 // destructor, give up.
85 if (UniqueBase) return true;
86 UniqueBase = Base;
87 }
88
89 // If we didn't find any bases with a non-trivial destructor, then
90 // the base destructor is actually effectively trivial, which can
91 // happen if it was needlessly user-defined or if there are virtual
92 // bases with non-trivial destructors.
93 if (!UniqueBase)
94 return true;
95
96 /// If we don't have a definition for the destructor yet, don't
97 /// emit. We can't emit aliases to declarations; that's just not
98 /// how aliases work.
99 const CXXDestructorDecl *BaseD = UniqueBase->getDestructor(getContext());
100 if (!BaseD->isImplicit() && !BaseD->getBody())
101 return true;
102
103 // If the base is at a non-zero offset, give up.
104 const ASTRecordLayout &ClassLayout = Context.getASTRecordLayout(Class);
105 if (ClassLayout.getBaseClassOffset(UniqueBase) != 0)
106 return true;
107
108 return TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Base),
109 GlobalDecl(BaseD, Dtor_Base));
110}
111
112/// Try to emit a definition as a global alias for another definition.
113bool CodeGenModule::TryEmitDefinitionAsAlias(GlobalDecl AliasDecl,
114 GlobalDecl TargetDecl) {
115 if (!getCodeGenOpts().CXXCtorDtorAliases)
116 return true;
117
118 // The alias will use the linkage of the referrent. If we can't
119 // support aliases with that linkage, fail.
120 llvm::GlobalValue::LinkageTypes Linkage
121 = getFunctionLinkage(cast<FunctionDecl>(AliasDecl.getDecl()));
122
123 switch (Linkage) {
124 // We can definitely emit aliases to definitions with external linkage.
125 case llvm::GlobalValue::ExternalLinkage:
126 case llvm::GlobalValue::ExternalWeakLinkage:
127 break;
128
129 // Same with local linkage.
130 case llvm::GlobalValue::InternalLinkage:
131 case llvm::GlobalValue::PrivateLinkage:
132 case llvm::GlobalValue::LinkerPrivateLinkage:
133 break;
134
135 // We should try to support linkonce linkages.
136 case llvm::GlobalValue::LinkOnceAnyLinkage:
137 case llvm::GlobalValue::LinkOnceODRLinkage:
138 return true;
139
140 // Other linkages will probably never be supported.
141 default:
142 return true;
143 }
144
145 llvm::GlobalValue::LinkageTypes TargetLinkage
146 = getFunctionLinkage(cast<FunctionDecl>(TargetDecl.getDecl()));
147
148 if (llvm::GlobalValue::isWeakForLinker(TargetLinkage))
149 return true;
150
151 // Derive the type for the alias.
152 const llvm::PointerType *AliasType
153 = getTypes().GetFunctionType(AliasDecl)->getPointerTo();
154
155 // Find the referrent. Some aliases might require a bitcast, in
156 // which case the caller is responsible for ensuring the soundness
157 // of these semantics.
158 llvm::GlobalValue *Ref = cast<llvm::GlobalValue>(GetAddrOfGlobal(TargetDecl));
159 llvm::Constant *Aliasee = Ref;
160 if (Ref->getType() != AliasType)
161 Aliasee = llvm::ConstantExpr::getBitCast(Ref, AliasType);
162
163 // Create the alias with no name.
164 llvm::GlobalAlias *Alias =
165 new llvm::GlobalAlias(AliasType, Linkage, "", Aliasee, &getModule());
166
167 // Switch any previous uses to the alias.
168 const char *MangledName = getMangledName(AliasDecl);
169 llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
170 if (Entry) {
171 assert(Entry->isDeclaration() && "definition already exists for alias");
172 assert(Entry->getType() == AliasType &&
173 "declaration exists with different type");
174 Entry->replaceAllUsesWith(Alias);
175 Entry->eraseFromParent();
176 }
177 Entry = Alias;
178
179 // Finally, set up the alias with its proper name and attributes.
180 Alias->setName(MangledName);
181 SetCommonAttributes(AliasDecl.getDecl(), Alias);
182
183 return false;
184}
185
186void CodeGenModule::EmitCXXConstructors(const CXXConstructorDecl *D) {
187 // The constructor used for constructing this as a complete class;
188 // constucts the virtual bases, then calls the base constructor.
189 EmitGlobal(GlobalDecl(D, Ctor_Complete));
190
191 // The constructor used for constructing this as a base class;
192 // ignores virtual bases.
193 EmitGlobal(GlobalDecl(D, Ctor_Base));
194}
195
196void CodeGenModule::EmitCXXConstructor(const CXXConstructorDecl *D,
197 CXXCtorType Type) {
198 // The complete constructor is equivalent to the base constructor
199 // for classes with no virtual bases. Try to emit it as an alias.
200 if (Type == Ctor_Complete &&
201 !D->getParent()->getNumVBases() &&
202 !TryEmitDefinitionAsAlias(GlobalDecl(D, Ctor_Complete),
203 GlobalDecl(D, Ctor_Base)))
204 return;
205
206 llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXConstructor(D, Type));
207
208 CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
209
210 SetFunctionDefinitionAttributes(D, Fn);
211 SetLLVMFunctionAttributesForDefinition(D, Fn);
212}
213
214llvm::GlobalValue *
215CodeGenModule::GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
216 CXXCtorType Type) {
217 const char *Name = getMangledCXXCtorName(D, Type);
218 if (llvm::GlobalValue *V = GlobalDeclMap[Name])
219 return V;
220
221 const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
222 const llvm::FunctionType *FTy =
223 getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type),
224 FPT->isVariadic());
225 return cast<llvm::Function>(
226 GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
227}
228
229const char *CodeGenModule::getMangledCXXCtorName(const CXXConstructorDecl *D,
230 CXXCtorType Type) {
231 llvm::SmallString<256> Name;
232 getMangleContext().mangleCXXCtor(D, Type, Name);
233
234 Name += '\0';
235 return UniqueMangledName(Name.begin(), Name.end());
236}
237
238void CodeGenModule::EmitCXXDestructors(const CXXDestructorDecl *D) {
239 // The destructor in a virtual table is always a 'deleting'
240 // destructor, which calls the complete destructor and then uses the
241 // appropriate operator delete.
242 if (D->isVirtual())
243 EmitGlobal(GlobalDecl(D, Dtor_Deleting));
244
245 // The destructor used for destructing this as a most-derived class;
246 // call the base destructor and then destructs any virtual bases.
247 EmitGlobal(GlobalDecl(D, Dtor_Complete));
248
249 // The destructor used for destructing this as a base class; ignores
250 // virtual bases.
251 EmitGlobal(GlobalDecl(D, Dtor_Base));
252}
253
254void CodeGenModule::EmitCXXDestructor(const CXXDestructorDecl *D,
255 CXXDtorType Type) {
256 // The complete destructor is equivalent to the base destructor for
257 // classes with no virtual bases, so try to emit it as an alias.
258 if (Type == Dtor_Complete &&
259 !D->getParent()->getNumVBases() &&
260 !TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Complete),
261 GlobalDecl(D, Dtor_Base)))
262 return;
263
264 // The base destructor is equivalent to the base destructor of its
265 // base class if there is exactly one non-virtual base class with a
266 // non-trivial destructor, there are no fields with a non-trivial
267 // destructor, and the body of the destructor is trivial.
268 if (Type == Dtor_Base && !TryEmitBaseDestructorAsAlias(D))
269 return;
270
271 llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXDestructor(D, Type));
272
273 CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
274
275 SetFunctionDefinitionAttributes(D, Fn);
276 SetLLVMFunctionAttributesForDefinition(D, Fn);
277}
278
279llvm::GlobalValue *
280CodeGenModule::GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
281 CXXDtorType Type) {
282 const char *Name = getMangledCXXDtorName(D, Type);
283 if (llvm::GlobalValue *V = GlobalDeclMap[Name])
284 return V;
285
286 const llvm::FunctionType *FTy =
287 getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type), false);
288
289 return cast<llvm::Function>(
290 GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
291}
292
293const char *CodeGenModule::getMangledCXXDtorName(const CXXDestructorDecl *D,
294 CXXDtorType Type) {
295 llvm::SmallString<256> Name;
296 getMangleContext().mangleCXXDtor(D, Type, Name);
297
298 Name += '\0';
299 return UniqueMangledName(Name.begin(), Name.end());
300}
301
302llvm::Constant *
303CodeGenFunction::GenerateThunk(llvm::Function *Fn, GlobalDecl GD,
304 bool Extern,
305 const ThunkAdjustment &ThisAdjustment) {
306 return GenerateCovariantThunk(Fn, GD, Extern,
307 CovariantThunkAdjustment(ThisAdjustment,
308 ThunkAdjustment()));
309}
310
311llvm::Value *
312CodeGenFunction::DynamicTypeAdjust(llvm::Value *V,
313 const ThunkAdjustment &Adjustment) {
314 const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
315
316 const llvm::Type *OrigTy = V->getType();
317 if (Adjustment.NonVirtual) {
318 // Do the non-virtual adjustment
319 V = Builder.CreateBitCast(V, Int8PtrTy);
320 V = Builder.CreateConstInBoundsGEP1_64(V, Adjustment.NonVirtual);
321 V = Builder.CreateBitCast(V, OrigTy);
322 }
323
324 if (!Adjustment.Virtual)
325 return V;
326
327 assert(Adjustment.Virtual % (LLVMPointerWidth / 8) == 0 &&
328 "vtable entry unaligned");
329
330 // Do the virtual this adjustment
331 const llvm::Type *PtrDiffTy = ConvertType(getContext().getPointerDiffType());
332 const llvm::Type *PtrDiffPtrTy = PtrDiffTy->getPointerTo();
333
334 llvm::Value *ThisVal = Builder.CreateBitCast(V, Int8PtrTy);
335 V = Builder.CreateBitCast(V, PtrDiffPtrTy->getPointerTo());
336 V = Builder.CreateLoad(V, "vtable");
337
338 llvm::Value *VTablePtr = V;
339 uint64_t VirtualAdjustment = Adjustment.Virtual / (LLVMPointerWidth / 8);
340 V = Builder.CreateConstInBoundsGEP1_64(VTablePtr, VirtualAdjustment);
341 V = Builder.CreateLoad(V);
342 V = Builder.CreateGEP(ThisVal, V);
343
344 return Builder.CreateBitCast(V, OrigTy);
345}
346
347llvm::Constant *
348CodeGenFunction::GenerateCovariantThunk(llvm::Function *Fn,
349 GlobalDecl GD, bool Extern,
350 const CovariantThunkAdjustment &Adjustment) {
351 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
352 const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
353 QualType ResultType = FPT->getResultType();
354
355 FunctionArgList Args;
356 ImplicitParamDecl *ThisDecl =
357 ImplicitParamDecl::Create(getContext(), 0, SourceLocation(), 0,
358 MD->getThisType(getContext()));
359 Args.push_back(std::make_pair(ThisDecl, ThisDecl->getType()));
360 for (FunctionDecl::param_const_iterator i = MD->param_begin(),
361 e = MD->param_end();
362 i != e; ++i) {
363 ParmVarDecl *D = *i;
364 Args.push_back(std::make_pair(D, D->getType()));
365 }
366 IdentifierInfo *II
367 = &CGM.getContext().Idents.get("__thunk_named_foo_");
368 FunctionDecl *FD = FunctionDecl::Create(getContext(),
369 getContext().getTranslationUnitDecl(),
370 SourceLocation(), II, ResultType, 0,
371 Extern
372 ? FunctionDecl::Extern
373 : FunctionDecl::Static,
374 false, true);
375 StartFunction(FD, ResultType, Fn, Args, SourceLocation());
376
377 // generate body
378 const llvm::Type *Ty =
379 CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
380 FPT->isVariadic());
381 llvm::Value *Callee = CGM.GetAddrOfFunction(GD, Ty);
382
383 CallArgList CallArgs;
384
385 bool ShouldAdjustReturnPointer = true;
386 QualType ArgType = MD->getThisType(getContext());
387 llvm::Value *Arg = Builder.CreateLoad(LocalDeclMap[ThisDecl], "this");
388 if (!Adjustment.ThisAdjustment.isEmpty()) {
389 // Do the this adjustment.
390 const llvm::Type *OrigTy = Callee->getType();
391 Arg = DynamicTypeAdjust(Arg, Adjustment.ThisAdjustment);
392
393 if (!Adjustment.ReturnAdjustment.isEmpty()) {
394 const CovariantThunkAdjustment &ReturnAdjustment =
395 CovariantThunkAdjustment(ThunkAdjustment(),
396 Adjustment.ReturnAdjustment);
397
398 Callee = CGM.BuildCovariantThunk(GD, Extern, ReturnAdjustment);
399
400 Callee = Builder.CreateBitCast(Callee, OrigTy);
401 ShouldAdjustReturnPointer = false;
402 }
403 }
404
405 CallArgs.push_back(std::make_pair(RValue::get(Arg), ArgType));
406
407 for (FunctionDecl::param_const_iterator i = MD->param_begin(),
408 e = MD->param_end();
409 i != e; ++i) {
410 ParmVarDecl *D = *i;
411 QualType ArgType = D->getType();
412
413 // llvm::Value *Arg = CGF.GetAddrOfLocalVar(Dst);
414 Expr *Arg = new (getContext()) DeclRefExpr(D, ArgType.getNonReferenceType(),
415 SourceLocation());
416 CallArgs.push_back(std::make_pair(EmitCallArg(Arg, ArgType), ArgType));
417 }
418
419 RValue RV = EmitCall(CGM.getTypes().getFunctionInfo(ResultType, CallArgs,
420 FPT->getCallConv(),
421 FPT->getNoReturnAttr()),
422 Callee, ReturnValueSlot(), CallArgs, MD);
423 if (ShouldAdjustReturnPointer && !Adjustment.ReturnAdjustment.isEmpty()) {
424 bool CanBeZero = !(ResultType->isReferenceType()
425 // FIXME: attr nonnull can't be zero either
426 /* || ResultType->hasAttr<NonNullAttr>() */ );
427 // Do the return result adjustment.
428 if (CanBeZero) {
429 llvm::BasicBlock *NonZeroBlock = createBasicBlock();
430 llvm::BasicBlock *ZeroBlock = createBasicBlock();
431 llvm::BasicBlock *ContBlock = createBasicBlock();
432
433 const llvm::Type *Ty = RV.getScalarVal()->getType();
434 llvm::Value *Zero = llvm::Constant::getNullValue(Ty);
435 Builder.CreateCondBr(Builder.CreateICmpNE(RV.getScalarVal(), Zero),
436 NonZeroBlock, ZeroBlock);
437 EmitBlock(NonZeroBlock);
438 llvm::Value *NZ =
439 DynamicTypeAdjust(RV.getScalarVal(), Adjustment.ReturnAdjustment);
440 EmitBranch(ContBlock);
441 EmitBlock(ZeroBlock);
442 llvm::Value *Z = RV.getScalarVal();
443 EmitBlock(ContBlock);
444 llvm::PHINode *RVOrZero = Builder.CreatePHI(Ty);
445 RVOrZero->reserveOperandSpace(2);
446 RVOrZero->addIncoming(NZ, NonZeroBlock);
447 RVOrZero->addIncoming(Z, ZeroBlock);
448 RV = RValue::get(RVOrZero);
449 } else
450 RV = RValue::get(DynamicTypeAdjust(RV.getScalarVal(),
451 Adjustment.ReturnAdjustment));
452 }
453
454 if (!ResultType->isVoidType())
455 EmitReturnOfRValue(RV, ResultType);
456
457 FinishFunction();
458 return Fn;
459}
460
461llvm::Constant *
462CodeGenModule::GetAddrOfThunk(GlobalDecl GD,
463 const ThunkAdjustment &ThisAdjustment) {
464 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
465
466 // Compute mangled name
467 llvm::SmallString<256> OutName;
468 if (const CXXDestructorDecl* DD = dyn_cast<CXXDestructorDecl>(MD))
469 getMangleContext().mangleCXXDtorThunk(DD, GD.getDtorType(), ThisAdjustment,
470 OutName);
471 else
472 getMangleContext().mangleThunk(MD, ThisAdjustment, OutName);
473 OutName += '\0';
474 const char* Name = UniqueMangledName(OutName.begin(), OutName.end());
475
476 // Get function for mangled name
477 const llvm::Type *Ty = getTypes().GetFunctionTypeForVtable(MD);
478 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl());
479}
480
481llvm::Constant *
482CodeGenModule::GetAddrOfCovariantThunk(GlobalDecl GD,
483 const CovariantThunkAdjustment &Adjustment) {
484 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
485
486 // Compute mangled name
487 llvm::SmallString<256> OutName;
488 getMangleContext().mangleCovariantThunk(MD, Adjustment, OutName);
489 OutName += '\0';
490 const char* Name = UniqueMangledName(OutName.begin(), OutName.end());
491
492 // Get function for mangled name
493 const llvm::Type *Ty = getTypes().GetFunctionTypeForVtable(MD);
494 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl());
495}
496
497void CodeGenModule::BuildThunksForVirtual(GlobalDecl GD) {
498 CGVtableInfo::AdjustmentVectorTy *AdjPtr = getVtableInfo().getAdjustments(GD);
499 if (!AdjPtr)
500 return;
501 CGVtableInfo::AdjustmentVectorTy &Adj = *AdjPtr;
502 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
503 for (unsigned i = 0; i < Adj.size(); i++) {
504 GlobalDecl OGD = Adj[i].first;
505 const CXXMethodDecl *OMD = cast<CXXMethodDecl>(OGD.getDecl());
506 QualType nc_oret = OMD->getType()->getAs<FunctionType>()->getResultType();
507 CanQualType oret = getContext().getCanonicalType(nc_oret);
508 QualType nc_ret = MD->getType()->getAs<FunctionType>()->getResultType();
509 CanQualType ret = getContext().getCanonicalType(nc_ret);
510 ThunkAdjustment ReturnAdjustment;
511 if (oret != ret) {
512 QualType qD = nc_ret->getPointeeType();
513 QualType qB = nc_oret->getPointeeType();
514 CXXRecordDecl *D = cast<CXXRecordDecl>(qD->getAs<RecordType>()->getDecl());
515 CXXRecordDecl *B = cast<CXXRecordDecl>(qB->getAs<RecordType>()->getDecl());
516 ReturnAdjustment = ComputeThunkAdjustment(D, B);
517 }
518 ThunkAdjustment ThisAdjustment = Adj[i].second;
519 bool Extern = !cast<CXXRecordDecl>(OMD->getDeclContext())->isInAnonymousNamespace();
520 if (!ReturnAdjustment.isEmpty() || !ThisAdjustment.isEmpty()) {
521 CovariantThunkAdjustment CoAdj(ThisAdjustment, ReturnAdjustment);
522 llvm::Constant *FnConst;
523 if (!ReturnAdjustment.isEmpty())
524 FnConst = GetAddrOfCovariantThunk(GD, CoAdj);
525 else
526 FnConst = GetAddrOfThunk(GD, ThisAdjustment);
527 if (!isa<llvm::Function>(FnConst)) {
528 llvm::Constant *SubExpr =
529 cast<llvm::ConstantExpr>(FnConst)->getOperand(0);
530 llvm::Function *OldFn = cast<llvm::Function>(SubExpr);
531 std::string Name = OldFn->getNameStr();
532 GlobalDeclMap.erase(UniqueMangledName(Name.data(),
533 Name.data() + Name.size() + 1));
534 llvm::Constant *NewFnConst;
535 if (!ReturnAdjustment.isEmpty())
536 NewFnConst = GetAddrOfCovariantThunk(GD, CoAdj);
537 else
538 NewFnConst = GetAddrOfThunk(GD, ThisAdjustment);
539 llvm::Function *NewFn = cast<llvm::Function>(NewFnConst);
540 NewFn->takeName(OldFn);
541 llvm::Constant *NewPtrForOldDecl =
542 llvm::ConstantExpr::getBitCast(NewFn, OldFn->getType());
543 OldFn->replaceAllUsesWith(NewPtrForOldDecl);
544 OldFn->eraseFromParent();
545 FnConst = NewFn;
546 }
547 llvm::Function *Fn = cast<llvm::Function>(FnConst);
548 if (Fn->isDeclaration()) {
549 llvm::GlobalVariable::LinkageTypes linktype;
550 linktype = llvm::GlobalValue::WeakAnyLinkage;
551 if (!Extern)
552 linktype = llvm::GlobalValue::InternalLinkage;
553 Fn->setLinkage(linktype);
554 if (!Features.Exceptions && !Features.ObjCNonFragileABI)
555 Fn->addFnAttr(llvm::Attribute::NoUnwind);
556 Fn->setAlignment(2);
557 CodeGenFunction(*this).GenerateCovariantThunk(Fn, GD, Extern, CoAdj);
558 }
559 }
560 }
561}
562
563llvm::Constant *
564CodeGenModule::BuildThunk(GlobalDecl GD, bool Extern,
565 const ThunkAdjustment &ThisAdjustment) {
566 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
567 llvm::SmallString<256> OutName;
568 if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(MD)) {
569 getMangleContext().mangleCXXDtorThunk(D, GD.getDtorType(), ThisAdjustment,
570 OutName);
571 } else
572 getMangleContext().mangleThunk(MD, ThisAdjustment, OutName);
573
574 llvm::GlobalVariable::LinkageTypes linktype;
575 linktype = llvm::GlobalValue::WeakAnyLinkage;
576 if (!Extern)
577 linktype = llvm::GlobalValue::InternalLinkage;
578 llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
579 const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
580 const llvm::FunctionType *FTy =
581 getTypes().GetFunctionType(getTypes().getFunctionInfo(MD),
582 FPT->isVariadic());
583
584 llvm::Function *Fn = llvm::Function::Create(FTy, linktype, OutName.str(),
585 &getModule());
586 CodeGenFunction(*this).GenerateThunk(Fn, GD, Extern, ThisAdjustment);
587 llvm::Constant *m = llvm::ConstantExpr::getBitCast(Fn, Ptr8Ty);
588 return m;
589}
590
591llvm::Constant *
592CodeGenModule::BuildCovariantThunk(const GlobalDecl &GD, bool Extern,
593 const CovariantThunkAdjustment &Adjustment) {
594 const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
595 llvm::SmallString<256> OutName;
596 getMangleContext().mangleCovariantThunk(MD, Adjustment, OutName);
597 llvm::GlobalVariable::LinkageTypes linktype;
598 linktype = llvm::GlobalValue::WeakAnyLinkage;
599 if (!Extern)
600 linktype = llvm::GlobalValue::InternalLinkage;
601 llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
602 const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
603 const llvm::FunctionType *FTy =
604 getTypes().GetFunctionType(getTypes().getFunctionInfo(MD),
605 FPT->isVariadic());
606
607 llvm::Function *Fn = llvm::Function::Create(FTy, linktype, OutName.str(),
608 &getModule());
609 CodeGenFunction(*this).GenerateCovariantThunk(Fn, MD, Extern, Adjustment);
610 llvm::Constant *m = llvm::ConstantExpr::getBitCast(Fn, Ptr8Ty);
611 return m;
612}
613
614static llvm::Value *BuildVirtualCall(CodeGenFunction &CGF, uint64_t VtableIndex,
615 llvm::Value *This, const llvm::Type *Ty) {
616 Ty = Ty->getPointerTo()->getPointerTo()->getPointerTo();
617
618 llvm::Value *Vtable = CGF.Builder.CreateBitCast(This, Ty);
619 Vtable = CGF.Builder.CreateLoad(Vtable);
620
621 llvm::Value *VFuncPtr =
622 CGF.Builder.CreateConstInBoundsGEP1_64(Vtable, VtableIndex, "vfn");
623 return CGF.Builder.CreateLoad(VFuncPtr);
624}
625
626llvm::Value *
627CodeGenFunction::BuildVirtualCall(const CXXMethodDecl *MD, llvm::Value *This,
628 const llvm::Type *Ty) {
629 MD = MD->getCanonicalDecl();
630 uint64_t VtableIndex = CGM.getVtableInfo().getMethodVtableIndex(MD);
631
632 return ::BuildVirtualCall(*this, VtableIndex, This, Ty);
633}
634
635llvm::Value *
636CodeGenFunction::BuildVirtualCall(const CXXDestructorDecl *DD, CXXDtorType Type,
637 llvm::Value *&This, const llvm::Type *Ty) {
638 DD = cast<CXXDestructorDecl>(DD->getCanonicalDecl());
639 uint64_t VtableIndex =
640 CGM.getVtableInfo().getMethodVtableIndex(GlobalDecl(DD, Type));
641
642 return ::BuildVirtualCall(*this, VtableIndex, This, Ty);
643}