1 //===--- CGClass.cpp - Emit LLVM Code for C++ classes ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This contains code dealing with C++ code generation of classes
12 //===----------------------------------------------------------------------===//
14 #include "CGDebugInfo.h"
15 #include "CodeGenFunction.h"
16 #include "clang/AST/CXXInheritance.h"
17 #include "clang/AST/EvaluatedExprVisitor.h"
18 #include "clang/AST/RecordLayout.h"
19 #include "clang/AST/StmtCXX.h"
20 #include "clang/Frontend/CodeGenOptions.h"
22 using namespace clang;
23 using namespace CodeGen;
26 ComputeNonVirtualBaseClassOffset(ASTContext &Context,
27 const CXXRecordDecl *DerivedClass,
28 CastExpr::path_const_iterator Start,
29 CastExpr::path_const_iterator End) {
30 CharUnits Offset = CharUnits::Zero();
32 const CXXRecordDecl *RD = DerivedClass;
34 for (CastExpr::path_const_iterator I = Start; I != End; ++I) {
35 const CXXBaseSpecifier *Base = *I;
36 assert(!Base->isVirtual() && "Should not see virtual bases here!");
39 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
41 const CXXRecordDecl *BaseDecl =
42 cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
45 Offset += Layout.getBaseClassOffset(BaseDecl);
54 CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
55 CastExpr::path_const_iterator PathBegin,
56 CastExpr::path_const_iterator PathEnd) {
57 assert(PathBegin != PathEnd && "Base path should not be empty!");
60 ComputeNonVirtualBaseClassOffset(getContext(), ClassDecl,
65 llvm::Type *PtrDiffTy =
66 Types.ConvertType(getContext().getPointerDiffType());
68 return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity());
71 /// Gets the address of a direct base class within a complete object.
72 /// This should only be used for (1) non-virtual bases or (2) virtual bases
73 /// when the type is known to be complete (e.g. in complete destructors).
75 /// The object pointed to by 'This' is assumed to be non-null.
77 CodeGenFunction::GetAddressOfDirectBaseInCompleteClass(llvm::Value *This,
78 const CXXRecordDecl *Derived,
79 const CXXRecordDecl *Base,
81 // 'this' must be a pointer (in some address space) to Derived.
82 assert(This->getType()->isPointerTy() &&
83 cast<llvm::PointerType>(This->getType())->getElementType()
84 == ConvertType(Derived));
86 // Compute the offset of the virtual base.
88 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
90 Offset = Layout.getVBaseClassOffset(Base);
92 Offset = Layout.getBaseClassOffset(Base);
94 // Shift and cast down to the base type.
95 // TODO: for complete types, this should be possible with a GEP.
96 llvm::Value *V = This;
97 if (Offset.isPositive()) {
98 llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
99 V = Builder.CreateBitCast(V, Int8PtrTy);
100 V = Builder.CreateConstInBoundsGEP1_64(V, Offset.getQuantity());
102 V = Builder.CreateBitCast(V, ConvertType(Base)->getPointerTo());
108 ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, llvm::Value *ThisPtr,
109 CharUnits NonVirtual, llvm::Value *Virtual) {
110 llvm::Type *PtrDiffTy =
111 CGF.ConvertType(CGF.getContext().getPointerDiffType());
113 llvm::Value *NonVirtualOffset = 0;
114 if (!NonVirtual.isZero())
115 NonVirtualOffset = llvm::ConstantInt::get(PtrDiffTy,
116 NonVirtual.getQuantity());
118 llvm::Value *BaseOffset;
120 if (NonVirtualOffset)
121 BaseOffset = CGF.Builder.CreateAdd(Virtual, NonVirtualOffset);
123 BaseOffset = Virtual;
125 BaseOffset = NonVirtualOffset;
127 // Apply the base offset.
128 llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
129 ThisPtr = CGF.Builder.CreateBitCast(ThisPtr, Int8PtrTy);
130 ThisPtr = CGF.Builder.CreateGEP(ThisPtr, BaseOffset, "add.ptr");
136 CodeGenFunction::GetAddressOfBaseClass(llvm::Value *Value,
137 const CXXRecordDecl *Derived,
138 CastExpr::path_const_iterator PathBegin,
139 CastExpr::path_const_iterator PathEnd,
140 bool NullCheckValue) {
141 assert(PathBegin != PathEnd && "Base path should not be empty!");
143 CastExpr::path_const_iterator Start = PathBegin;
144 const CXXRecordDecl *VBase = 0;
146 // Get the virtual base.
147 if ((*Start)->isVirtual()) {
149 cast<CXXRecordDecl>((*Start)->getType()->getAs<RecordType>()->getDecl());
153 CharUnits NonVirtualOffset =
154 ComputeNonVirtualBaseClassOffset(getContext(), VBase ? VBase : Derived,
157 // Get the base pointer type.
158 llvm::Type *BasePtrTy =
159 ConvertType((PathEnd[-1])->getType())->getPointerTo();
161 if (NonVirtualOffset.isZero() && !VBase) {
163 return Builder.CreateBitCast(Value, BasePtrTy);
166 llvm::BasicBlock *CastNull = 0;
167 llvm::BasicBlock *CastNotNull = 0;
168 llvm::BasicBlock *CastEnd = 0;
170 if (NullCheckValue) {
171 CastNull = createBasicBlock("cast.null");
172 CastNotNull = createBasicBlock("cast.notnull");
173 CastEnd = createBasicBlock("cast.end");
175 llvm::Value *IsNull = Builder.CreateIsNull(Value);
176 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
177 EmitBlock(CastNotNull);
180 llvm::Value *VirtualOffset = 0;
183 if (Derived->hasAttr<FinalAttr>()) {
186 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
188 CharUnits VBaseOffset = Layout.getVBaseClassOffset(VBase);
189 NonVirtualOffset += VBaseOffset;
191 VirtualOffset = GetVirtualBaseClassOffset(Value, Derived, VBase);
194 // Apply the offsets.
195 Value = ApplyNonVirtualAndVirtualOffset(*this, Value,
200 Value = Builder.CreateBitCast(Value, BasePtrTy);
202 if (NullCheckValue) {
203 Builder.CreateBr(CastEnd);
205 Builder.CreateBr(CastEnd);
208 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
209 PHI->addIncoming(Value, CastNotNull);
210 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
219 CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value,
220 const CXXRecordDecl *Derived,
221 CastExpr::path_const_iterator PathBegin,
222 CastExpr::path_const_iterator PathEnd,
223 bool NullCheckValue) {
224 assert(PathBegin != PathEnd && "Base path should not be empty!");
227 getContext().getCanonicalType(getContext().getTagDeclType(Derived));
228 llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
230 llvm::Value *NonVirtualOffset =
231 CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
233 if (!NonVirtualOffset) {
234 // No offset, we can just cast back.
235 return Builder.CreateBitCast(Value, DerivedPtrTy);
238 llvm::BasicBlock *CastNull = 0;
239 llvm::BasicBlock *CastNotNull = 0;
240 llvm::BasicBlock *CastEnd = 0;
242 if (NullCheckValue) {
243 CastNull = createBasicBlock("cast.null");
244 CastNotNull = createBasicBlock("cast.notnull");
245 CastEnd = createBasicBlock("cast.end");
247 llvm::Value *IsNull = Builder.CreateIsNull(Value);
248 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
249 EmitBlock(CastNotNull);
253 Value = Builder.CreatePtrToInt(Value, NonVirtualOffset->getType());
254 Value = Builder.CreateSub(Value, NonVirtualOffset);
255 Value = Builder.CreateIntToPtr(Value, DerivedPtrTy);
258 Value = Builder.CreateBitCast(Value, DerivedPtrTy);
260 if (NullCheckValue) {
261 Builder.CreateBr(CastEnd);
263 Builder.CreateBr(CastEnd);
266 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
267 PHI->addIncoming(Value, CastNotNull);
268 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
276 /// GetVTTParameter - Return the VTT parameter that should be passed to a
277 /// base constructor/destructor with virtual bases.
278 static llvm::Value *GetVTTParameter(CodeGenFunction &CGF, GlobalDecl GD,
279 bool ForVirtualBase) {
280 if (!CodeGenVTables::needsVTTParameter(GD)) {
281 // This constructor/destructor does not need a VTT parameter.
285 const CXXRecordDecl *RD = cast<CXXMethodDecl>(CGF.CurFuncDecl)->getParent();
286 const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent();
290 uint64_t SubVTTIndex;
292 // If the record matches the base, this is the complete ctor/dtor
293 // variant calling the base variant in a class with virtual bases.
295 assert(!CodeGenVTables::needsVTTParameter(CGF.CurGD) &&
296 "doing no-op VTT offset in base dtor/ctor?");
297 assert(!ForVirtualBase && "Can't have same class as virtual base!");
300 const ASTRecordLayout &Layout =
301 CGF.getContext().getASTRecordLayout(RD);
302 CharUnits BaseOffset = ForVirtualBase ?
303 Layout.getVBaseClassOffset(Base) :
304 Layout.getBaseClassOffset(Base);
307 CGF.CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset));
308 assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
311 if (CodeGenVTables::needsVTTParameter(CGF.CurGD)) {
312 // A VTT parameter was passed to the constructor, use it.
313 VTT = CGF.LoadCXXVTT();
314 VTT = CGF.Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex);
316 // We're the complete constructor, so get the VTT by name.
317 VTT = CGF.CGM.getVTables().GetAddrOfVTT(RD);
318 VTT = CGF.Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
325 /// Call the destructor for a direct base class.
326 struct CallBaseDtor : EHScopeStack::Cleanup {
327 const CXXRecordDecl *BaseClass;
329 CallBaseDtor(const CXXRecordDecl *Base, bool BaseIsVirtual)
330 : BaseClass(Base), BaseIsVirtual(BaseIsVirtual) {}
332 void Emit(CodeGenFunction &CGF, Flags flags) {
333 const CXXRecordDecl *DerivedClass =
334 cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent();
336 const CXXDestructorDecl *D = BaseClass->getDestructor();
338 CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThis(),
339 DerivedClass, BaseClass,
341 CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual, Addr);
345 /// A visitor which checks whether an initializer uses 'this' in a
346 /// way which requires the vtable to be properly set.
347 struct DynamicThisUseChecker : EvaluatedExprVisitor<DynamicThisUseChecker> {
348 typedef EvaluatedExprVisitor<DynamicThisUseChecker> super;
352 DynamicThisUseChecker(ASTContext &C) : super(C), UsesThis(false) {}
354 // Black-list all explicit and implicit references to 'this'.
356 // Do we need to worry about external references to 'this' derived
357 // from arbitrary code? If so, then anything which runs arbitrary
358 // external code might potentially access the vtable.
359 void VisitCXXThisExpr(CXXThisExpr *E) { UsesThis = true; }
363 static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
364 DynamicThisUseChecker Checker(C);
365 Checker.Visit(const_cast<Expr*>(Init));
366 return Checker.UsesThis;
369 static void EmitBaseInitializer(CodeGenFunction &CGF,
370 const CXXRecordDecl *ClassDecl,
371 CXXCtorInitializer *BaseInit,
372 CXXCtorType CtorType) {
373 assert(BaseInit->isBaseInitializer() &&
374 "Must have base initializer!");
376 llvm::Value *ThisPtr = CGF.LoadCXXThis();
378 const Type *BaseType = BaseInit->getBaseClass();
379 CXXRecordDecl *BaseClassDecl =
380 cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
382 bool isBaseVirtual = BaseInit->isBaseVirtual();
384 // The base constructor doesn't construct virtual bases.
385 if (CtorType == Ctor_Base && isBaseVirtual)
388 // If the initializer for the base (other than the constructor
389 // itself) accesses 'this' in any way, we need to initialize the
391 if (BaseInitializerUsesThis(CGF.getContext(), BaseInit->getInit()))
392 CGF.InitializeVTablePointers(ClassDecl);
394 // We can pretend to be a complete class because it only matters for
395 // virtual bases, and we only do virtual bases for complete ctors.
397 CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl,
401 AggValueSlot AggSlot =
402 AggValueSlot::forAddr(V, Qualifiers(),
403 AggValueSlot::IsDestructed,
404 AggValueSlot::DoesNotNeedGCBarriers,
405 AggValueSlot::IsNotAliased);
407 CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
409 if (CGF.CGM.getLangOptions().Exceptions &&
410 !BaseClassDecl->hasTrivialDestructor())
411 CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
415 static void EmitAggMemberInitializer(CodeGenFunction &CGF,
417 llvm::Value *ArrayIndexVar,
418 CXXCtorInitializer *MemberInit,
421 if (Index == MemberInit->getNumArrayIndices()) {
422 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
424 llvm::Value *Dest = LHS.getAddress();
426 // If we have an array index variable, load it and use it as an offset.
427 // Then, increment the value.
428 llvm::Value *ArrayIndex = CGF.Builder.CreateLoad(ArrayIndexVar);
429 Dest = CGF.Builder.CreateInBoundsGEP(Dest, ArrayIndex, "destaddress");
430 llvm::Value *Next = llvm::ConstantInt::get(ArrayIndex->getType(), 1);
431 Next = CGF.Builder.CreateAdd(ArrayIndex, Next, "inc");
432 CGF.Builder.CreateStore(Next, ArrayIndexVar);
435 if (!CGF.hasAggregateLLVMType(T)) {
436 LValue lvalue = CGF.MakeAddrLValue(Dest, T);
437 CGF.EmitScalarInit(MemberInit->getInit(), /*decl*/ 0, lvalue, false);
438 } else if (T->isAnyComplexType()) {
439 CGF.EmitComplexExprIntoAddr(MemberInit->getInit(), Dest,
440 LHS.isVolatileQualified());
443 AggValueSlot::forAddr(Dest, LHS.getQuals(),
444 AggValueSlot::IsDestructed,
445 AggValueSlot::DoesNotNeedGCBarriers,
446 AggValueSlot::IsNotAliased);
448 CGF.EmitAggExpr(MemberInit->getInit(), Slot);
454 const ConstantArrayType *Array = CGF.getContext().getAsConstantArrayType(T);
455 assert(Array && "Array initialization without the array type?");
456 llvm::Value *IndexVar
457 = CGF.GetAddrOfLocalVar(MemberInit->getArrayIndex(Index));
458 assert(IndexVar && "Array index variable not loaded");
460 // Initialize this index variable to zero.
462 = llvm::Constant::getNullValue(
463 CGF.ConvertType(CGF.getContext().getSizeType()));
464 CGF.Builder.CreateStore(Zero, IndexVar);
466 // Start the loop with a block that tests the condition.
467 llvm::BasicBlock *CondBlock = CGF.createBasicBlock("for.cond");
468 llvm::BasicBlock *AfterFor = CGF.createBasicBlock("for.end");
470 CGF.EmitBlock(CondBlock);
472 llvm::BasicBlock *ForBody = CGF.createBasicBlock("for.body");
473 // Generate: if (loop-index < number-of-elements) fall to the loop body,
474 // otherwise, go to the block after the for-loop.
475 uint64_t NumElements = Array->getSize().getZExtValue();
476 llvm::Value *Counter = CGF.Builder.CreateLoad(IndexVar);
477 llvm::Value *NumElementsPtr =
478 llvm::ConstantInt::get(Counter->getType(), NumElements);
479 llvm::Value *IsLess = CGF.Builder.CreateICmpULT(Counter, NumElementsPtr,
482 // If the condition is true, execute the body.
483 CGF.Builder.CreateCondBr(IsLess, ForBody, AfterFor);
485 CGF.EmitBlock(ForBody);
486 llvm::BasicBlock *ContinueBlock = CGF.createBasicBlock("for.inc");
489 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
491 // Inside the loop body recurse to emit the inner loop or, eventually, the
493 EmitAggMemberInitializer(CGF, LHS, ArrayIndexVar, MemberInit,
494 Array->getElementType(), Index + 1);
497 CGF.EmitBlock(ContinueBlock);
499 // Emit the increment of the loop counter.
500 llvm::Value *NextVal = llvm::ConstantInt::get(Counter->getType(), 1);
501 Counter = CGF.Builder.CreateLoad(IndexVar);
502 NextVal = CGF.Builder.CreateAdd(Counter, NextVal, "inc");
503 CGF.Builder.CreateStore(NextVal, IndexVar);
505 // Finally, branch back up to the condition for the next iteration.
506 CGF.EmitBranch(CondBlock);
508 // Emit the fall-through block.
509 CGF.EmitBlock(AfterFor, true);
513 struct CallMemberDtor : EHScopeStack::Cleanup {
515 CXXDestructorDecl *Dtor;
517 CallMemberDtor(FieldDecl *Field, CXXDestructorDecl *Dtor)
518 : Field(Field), Dtor(Dtor) {}
520 void Emit(CodeGenFunction &CGF, Flags flags) {
521 // FIXME: Is this OK for C++0x delegating constructors?
522 llvm::Value *ThisPtr = CGF.LoadCXXThis();
523 LValue LHS = CGF.EmitLValueForField(ThisPtr, Field, 0);
525 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
531 static bool hasTrivialCopyOrMoveConstructor(const CXXRecordDecl *Record,
533 return Moving ? Record->hasTrivialMoveConstructor() :
534 Record->hasTrivialCopyConstructor();
537 static void EmitMemberInitializer(CodeGenFunction &CGF,
538 const CXXRecordDecl *ClassDecl,
539 CXXCtorInitializer *MemberInit,
540 const CXXConstructorDecl *Constructor,
541 FunctionArgList &Args) {
542 assert(MemberInit->isAnyMemberInitializer() &&
543 "Must have member initializer!");
544 assert(MemberInit->getInit() && "Must have initializer!");
546 // non-static data member initializers.
547 FieldDecl *Field = MemberInit->getAnyMember();
548 QualType FieldType = CGF.getContext().getCanonicalType(Field->getType());
550 llvm::Value *ThisPtr = CGF.LoadCXXThis();
553 // If we are initializing an anonymous union field, drill down to the field.
554 if (MemberInit->isIndirectMemberInitializer()) {
555 LHS = CGF.EmitLValueForAnonRecordField(ThisPtr,
556 MemberInit->getIndirectMember(), 0);
557 FieldType = MemberInit->getIndirectMember()->getAnonField()->getType();
559 LHS = CGF.EmitLValueForFieldInitialization(ThisPtr, Field, 0);
562 if (!CGF.hasAggregateLLVMType(Field->getType())) {
563 if (LHS.isSimple()) {
564 CGF.EmitExprAsInit(MemberInit->getInit(), Field, LHS, false);
566 RValue RHS = RValue::get(CGF.EmitScalarExpr(MemberInit->getInit()));
567 CGF.EmitStoreThroughLValue(RHS, LHS);
569 } else if (MemberInit->getInit()->getType()->isAnyComplexType()) {
570 CGF.EmitComplexExprIntoAddr(MemberInit->getInit(), LHS.getAddress(),
571 LHS.isVolatileQualified());
573 llvm::Value *ArrayIndexVar = 0;
574 const ConstantArrayType *Array
575 = CGF.getContext().getAsConstantArrayType(FieldType);
576 if (Array && Constructor->isImplicitlyDefined() &&
577 Constructor->isCopyOrMoveConstructor()) {
579 = CGF.ConvertType(CGF.getContext().getSizeType());
581 // The LHS is a pointer to the first object we'll be constructing, as
583 QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
584 llvm::Type *BasePtr = CGF.ConvertType(BaseElementTy);
585 BasePtr = llvm::PointerType::getUnqual(BasePtr);
586 llvm::Value *BaseAddrPtr = CGF.Builder.CreateBitCast(LHS.getAddress(),
588 LHS = CGF.MakeAddrLValue(BaseAddrPtr, BaseElementTy);
590 // Create an array index that will be used to walk over all of the
591 // objects we're constructing.
592 ArrayIndexVar = CGF.CreateTempAlloca(SizeTy, "object.index");
593 llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy);
594 CGF.Builder.CreateStore(Zero, ArrayIndexVar);
596 // If we are copying an array of PODs or classes with trivial copy
597 // constructors, perform a single aggregate copy.
598 const CXXRecordDecl *Record = BaseElementTy->getAsCXXRecordDecl();
599 if (BaseElementTy.isPODType(CGF.getContext()) ||
600 (Record && hasTrivialCopyOrMoveConstructor(Record,
601 Constructor->isMoveConstructor()))) {
602 // Find the source pointer. We knows it's the last argument because
603 // we know we're in a copy constructor.
604 unsigned SrcArgIndex = Args.size() - 1;
606 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
607 LValue Src = CGF.EmitLValueForFieldInitialization(SrcPtr, Field, 0);
609 // Copy the aggregate.
610 CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType,
611 LHS.isVolatileQualified());
615 // Emit the block variables for the array indices, if any.
616 for (unsigned I = 0, N = MemberInit->getNumArrayIndices(); I != N; ++I)
617 CGF.EmitAutoVarDecl(*MemberInit->getArrayIndex(I));
620 EmitAggMemberInitializer(CGF, LHS, ArrayIndexVar, MemberInit, FieldType, 0);
622 if (!CGF.CGM.getLangOptions().Exceptions)
625 // FIXME: If we have an array of classes w/ non-trivial destructors,
626 // we need to destroy in reverse order of construction along the exception
628 const RecordType *RT = FieldType->getAs<RecordType>();
632 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
633 if (!RD->hasTrivialDestructor())
634 CGF.EHStack.pushCleanup<CallMemberDtor>(EHCleanup, Field,
635 RD->getDestructor());
639 /// Checks whether the given constructor is a valid subject for the
640 /// complete-to-base constructor delegation optimization, i.e.
641 /// emitting the complete constructor as a simple call to the base
643 static bool IsConstructorDelegationValid(const CXXConstructorDecl *Ctor) {
645 // Currently we disable the optimization for classes with virtual
646 // bases because (1) the addresses of parameter variables need to be
647 // consistent across all initializers but (2) the delegate function
648 // call necessarily creates a second copy of the parameter variable.
650 // The limiting example (purely theoretical AFAIK):
651 // struct A { A(int &c) { c++; } };
652 // struct B : virtual A {
653 // B(int count) : A(count) { printf("%d\n", count); }
655 // ...although even this example could in principle be emitted as a
656 // delegation since the address of the parameter doesn't escape.
657 if (Ctor->getParent()->getNumVBases()) {
658 // TODO: white-list trivial vbase initializers. This case wouldn't
659 // be subject to the restrictions below.
661 // TODO: white-list cases where:
662 // - there are no non-reference parameters to the constructor
663 // - the initializers don't access any non-reference parameters
664 // - the initializers don't take the address of non-reference
667 // If we ever add any of the above cases, remember that:
668 // - function-try-blocks will always blacklist this optimization
669 // - we need to perform the constructor prologue and cleanup in
670 // EmitConstructorBody.
675 // We also disable the optimization for variadic functions because
676 // it's impossible to "re-pass" varargs.
677 if (Ctor->getType()->getAs<FunctionProtoType>()->isVariadic())
680 // FIXME: Decide if we can do a delegation of a delegating constructor.
681 if (Ctor->isDelegatingConstructor())
687 /// EmitConstructorBody - Emits the body of the current constructor.
688 void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
689 const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
690 CXXCtorType CtorType = CurGD.getCtorType();
692 // Before we go any further, try the complete->base constructor
693 // delegation optimization.
694 if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor)) {
695 if (CGDebugInfo *DI = getDebugInfo())
696 DI->EmitLocation(Builder, Ctor->getLocEnd());
697 EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args);
701 Stmt *Body = Ctor->getBody();
703 // Enter the function-try-block before the constructor prologue if
705 bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
707 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
709 EHScopeStack::stable_iterator CleanupDepth = EHStack.stable_begin();
711 // Emit the constructor prologue, i.e. the base and member
713 EmitCtorPrologue(Ctor, CtorType, Args);
715 // Emit the body of the statement.
717 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
721 // Emit any cleanup blocks associated with the member or base
722 // initializers, which includes (along the exceptional path) the
723 // destructors for those members and bases that were fully
725 PopCleanupBlocks(CleanupDepth);
728 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
731 /// EmitCtorPrologue - This routine generates necessary code to initialize
732 /// base classes and non-static data members belonging to this constructor.
733 void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
734 CXXCtorType CtorType,
735 FunctionArgList &Args) {
736 if (CD->isDelegatingConstructor())
737 return EmitDelegatingCXXConstructorCall(CD, Args);
739 const CXXRecordDecl *ClassDecl = CD->getParent();
741 SmallVector<CXXCtorInitializer *, 8> MemberInitializers;
743 for (CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
746 CXXCtorInitializer *Member = (*B);
748 if (Member->isBaseInitializer()) {
749 EmitBaseInitializer(*this, ClassDecl, Member, CtorType);
751 assert(Member->isAnyMemberInitializer() &&
752 "Delegating initializer on non-delegating constructor");
753 MemberInitializers.push_back(Member);
757 InitializeVTablePointers(ClassDecl);
759 for (unsigned I = 0, E = MemberInitializers.size(); I != E; ++I)
760 EmitMemberInitializer(*this, ClassDecl, MemberInitializers[I], CD, Args);
764 FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field);
767 HasTrivialDestructorBody(ASTContext &Context,
768 const CXXRecordDecl *BaseClassDecl,
769 const CXXRecordDecl *MostDerivedClassDecl)
771 // If the destructor is trivial we don't have to check anything else.
772 if (BaseClassDecl->hasTrivialDestructor())
775 if (!BaseClassDecl->getDestructor()->hasTrivialBody())
779 for (CXXRecordDecl::field_iterator I = BaseClassDecl->field_begin(),
780 E = BaseClassDecl->field_end(); I != E; ++I) {
781 const FieldDecl *Field = *I;
783 if (!FieldHasTrivialDestructorBody(Context, Field))
787 // Check non-virtual bases.
788 for (CXXRecordDecl::base_class_const_iterator I =
789 BaseClassDecl->bases_begin(), E = BaseClassDecl->bases_end();
794 const CXXRecordDecl *NonVirtualBase =
795 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
796 if (!HasTrivialDestructorBody(Context, NonVirtualBase,
797 MostDerivedClassDecl))
801 if (BaseClassDecl == MostDerivedClassDecl) {
802 // Check virtual bases.
803 for (CXXRecordDecl::base_class_const_iterator I =
804 BaseClassDecl->vbases_begin(), E = BaseClassDecl->vbases_end();
806 const CXXRecordDecl *VirtualBase =
807 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
808 if (!HasTrivialDestructorBody(Context, VirtualBase,
809 MostDerivedClassDecl))
818 FieldHasTrivialDestructorBody(ASTContext &Context,
819 const FieldDecl *Field)
821 QualType FieldBaseElementType = Context.getBaseElementType(Field->getType());
823 const RecordType *RT = FieldBaseElementType->getAs<RecordType>();
827 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
828 return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl);
831 /// CanSkipVTablePointerInitialization - Check whether we need to initialize
832 /// any vtable pointers before calling this destructor.
833 static bool CanSkipVTablePointerInitialization(ASTContext &Context,
834 const CXXDestructorDecl *Dtor) {
835 if (!Dtor->hasTrivialBody())
839 const CXXRecordDecl *ClassDecl = Dtor->getParent();
840 for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
841 E = ClassDecl->field_end(); I != E; ++I) {
842 const FieldDecl *Field = *I;
844 if (!FieldHasTrivialDestructorBody(Context, Field))
851 /// EmitDestructorBody - Emits the body of the current destructor.
852 void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
853 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
854 CXXDtorType DtorType = CurGD.getDtorType();
856 // The call to operator delete in a deleting destructor happens
857 // outside of the function-try-block, which means it's always
858 // possible to delegate the destructor body to the complete
859 // destructor. Do so.
860 if (DtorType == Dtor_Deleting) {
861 EnterDtorCleanups(Dtor, Dtor_Deleting);
862 EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
868 Stmt *Body = Dtor->getBody();
870 // If the body is a function-try-block, enter the try before
872 bool isTryBody = (Body && isa<CXXTryStmt>(Body));
874 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
876 // Enter the epilogue cleanups.
877 RunCleanupsScope DtorEpilogue(*this);
879 // If this is the complete variant, just invoke the base variant;
880 // the epilogue will destruct the virtual bases. But we can't do
881 // this optimization if the body is a function-try-block, because
882 // we'd introduce *two* handler blocks.
884 case Dtor_Deleting: llvm_unreachable("already handled deleting case");
887 // Enter the cleanup scopes for virtual bases.
888 EnterDtorCleanups(Dtor, Dtor_Complete);
891 EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
895 // Fallthrough: act like we're in the base variant.
898 // Enter the cleanup scopes for fields and non-virtual bases.
899 EnterDtorCleanups(Dtor, Dtor_Base);
901 // Initialize the vtable pointers before entering the body.
902 if (!CanSkipVTablePointerInitialization(getContext(), Dtor))
903 InitializeVTablePointers(Dtor->getParent());
906 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
910 assert(Dtor->isImplicit() && "bodyless dtor not implicit");
911 // nothing to do besides what's in the epilogue
913 // -fapple-kext must inline any call to this dtor into
914 // the caller's body.
915 if (getContext().getLangOptions().AppleKext)
916 CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
920 // Jump out through the epilogue cleanups.
921 DtorEpilogue.ForceCleanup();
923 // Exit the try if applicable.
925 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
929 /// Call the operator delete associated with the current destructor.
930 struct CallDtorDelete : EHScopeStack::Cleanup {
933 void Emit(CodeGenFunction &CGF, Flags flags) {
934 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
935 const CXXRecordDecl *ClassDecl = Dtor->getParent();
936 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
937 CGF.getContext().getTagDeclType(ClassDecl));
941 class DestroyField : public EHScopeStack::Cleanup {
942 const FieldDecl *field;
943 CodeGenFunction::Destroyer &destroyer;
944 bool useEHCleanupForArray;
947 DestroyField(const FieldDecl *field, CodeGenFunction::Destroyer *destroyer,
948 bool useEHCleanupForArray)
949 : field(field), destroyer(*destroyer),
950 useEHCleanupForArray(useEHCleanupForArray) {}
952 void Emit(CodeGenFunction &CGF, Flags flags) {
953 // Find the address of the field.
954 llvm::Value *thisValue = CGF.LoadCXXThis();
955 LValue LV = CGF.EmitLValueForField(thisValue, field, /*CVRQualifiers=*/0);
956 assert(LV.isSimple());
958 CGF.emitDestroy(LV.getAddress(), field->getType(), destroyer,
959 flags.isForNormalCleanup() && useEHCleanupForArray);
964 /// EmitDtorEpilogue - Emit all code that comes at the end of class's
965 /// destructor. This is to call destructors on members and base classes
966 /// in reverse order of their construction.
967 void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD,
968 CXXDtorType DtorType) {
969 assert(!DD->isTrivial() &&
970 "Should not emit dtor epilogue for trivial dtor!");
972 // The deleting-destructor phase just needs to call the appropriate
973 // operator delete that Sema picked up.
974 if (DtorType == Dtor_Deleting) {
975 assert(DD->getOperatorDelete() &&
976 "operator delete missing - EmitDtorEpilogue");
977 EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
981 const CXXRecordDecl *ClassDecl = DD->getParent();
983 // Unions have no bases and do not call field destructors.
984 if (ClassDecl->isUnion())
987 // The complete-destructor phase just destructs all the virtual bases.
988 if (DtorType == Dtor_Complete) {
990 // We push them in the forward order so that they'll be popped in
991 // the reverse order.
992 for (CXXRecordDecl::base_class_const_iterator I =
993 ClassDecl->vbases_begin(), E = ClassDecl->vbases_end();
995 const CXXBaseSpecifier &Base = *I;
996 CXXRecordDecl *BaseClassDecl
997 = cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
999 // Ignore trivial destructors.
1000 if (BaseClassDecl->hasTrivialDestructor())
1003 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1005 /*BaseIsVirtual*/ true);
1011 assert(DtorType == Dtor_Base);
1013 // Destroy non-virtual bases.
1014 for (CXXRecordDecl::base_class_const_iterator I =
1015 ClassDecl->bases_begin(), E = ClassDecl->bases_end(); I != E; ++I) {
1016 const CXXBaseSpecifier &Base = *I;
1018 // Ignore virtual bases.
1019 if (Base.isVirtual())
1022 CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
1024 // Ignore trivial destructors.
1025 if (BaseClassDecl->hasTrivialDestructor())
1028 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1030 /*BaseIsVirtual*/ false);
1033 // Destroy direct fields.
1034 SmallVector<const FieldDecl *, 16> FieldDecls;
1035 for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
1036 E = ClassDecl->field_end(); I != E; ++I) {
1037 const FieldDecl *field = *I;
1038 QualType type = field->getType();
1039 QualType::DestructionKind dtorKind = type.isDestructedType();
1040 if (!dtorKind) continue;
1042 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1043 EHStack.pushCleanup<DestroyField>(cleanupKind, field,
1044 getDestroyer(dtorKind),
1045 cleanupKind & EHCleanup);
1049 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1050 /// constructor for each of several members of an array.
1052 /// \param ctor the constructor to call for each element
1053 /// \param argBegin,argEnd the arguments to evaluate and pass to the
1055 /// \param arrayType the type of the array to initialize
1056 /// \param arrayBegin an arrayType*
1057 /// \param zeroInitialize true if each element should be
1058 /// zero-initialized before it is constructed
1060 CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1061 const ConstantArrayType *arrayType,
1062 llvm::Value *arrayBegin,
1063 CallExpr::const_arg_iterator argBegin,
1064 CallExpr::const_arg_iterator argEnd,
1065 bool zeroInitialize) {
1066 QualType elementType;
1067 llvm::Value *numElements =
1068 emitArrayLength(arrayType, elementType, arrayBegin);
1070 EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin,
1071 argBegin, argEnd, zeroInitialize);
1074 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1075 /// constructor for each of several members of an array.
1077 /// \param ctor the constructor to call for each element
1078 /// \param numElements the number of elements in the array;
1080 /// \param argBegin,argEnd the arguments to evaluate and pass to the
1082 /// \param arrayBegin a T*, where T is the type constructed by ctor
1083 /// \param zeroInitialize true if each element should be
1084 /// zero-initialized before it is constructed
1086 CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1087 llvm::Value *numElements,
1088 llvm::Value *arrayBegin,
1089 CallExpr::const_arg_iterator argBegin,
1090 CallExpr::const_arg_iterator argEnd,
1091 bool zeroInitialize) {
1093 // It's legal for numElements to be zero. This can happen both
1094 // dynamically, because x can be zero in 'new A[x]', and statically,
1095 // because of GCC extensions that permit zero-length arrays. There
1096 // are probably legitimate places where we could assume that this
1097 // doesn't happen, but it's not clear that it's worth it.
1098 llvm::BranchInst *zeroCheckBranch = 0;
1100 // Optimize for a constant count.
1101 llvm::ConstantInt *constantCount
1102 = dyn_cast<llvm::ConstantInt>(numElements);
1103 if (constantCount) {
1104 // Just skip out if the constant count is zero.
1105 if (constantCount->isZero()) return;
1107 // Otherwise, emit the check.
1109 llvm::BasicBlock *loopBB = createBasicBlock("new.ctorloop");
1110 llvm::Value *iszero = Builder.CreateIsNull(numElements, "isempty");
1111 zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB);
1115 // Find the end of the array.
1116 llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(arrayBegin, numElements,
1119 // Enter the loop, setting up a phi for the current location to initialize.
1120 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1121 llvm::BasicBlock *loopBB = createBasicBlock("arrayctor.loop");
1123 llvm::PHINode *cur = Builder.CreatePHI(arrayBegin->getType(), 2,
1125 cur->addIncoming(arrayBegin, entryBB);
1127 // Inside the loop body, emit the constructor call on the array element.
1129 QualType type = getContext().getTypeDeclType(ctor->getParent());
1131 // Zero initialize the storage, if requested.
1133 EmitNullInitialization(cur, type);
1135 // C++ [class.temporary]p4:
1136 // There are two contexts in which temporaries are destroyed at a different
1137 // point than the end of the full-expression. The first context is when a
1138 // default constructor is called to initialize an element of an array.
1139 // If the constructor has one or more default arguments, the destruction of
1140 // every temporary created in a default argument expression is sequenced
1141 // before the construction of the next array element, if any.
1144 RunCleanupsScope Scope(*this);
1146 // Evaluate the constructor and its arguments in a regular
1147 // partial-destroy cleanup.
1148 if (getLangOptions().Exceptions &&
1149 !ctor->getParent()->hasTrivialDestructor()) {
1150 Destroyer *destroyer = destroyCXXObject;
1151 pushRegularPartialArrayCleanup(arrayBegin, cur, type, *destroyer);
1154 EmitCXXConstructorCall(ctor, Ctor_Complete, /*ForVirtualBase=*/ false,
1155 cur, argBegin, argEnd);
1158 // Go to the next element.
1160 Builder.CreateInBoundsGEP(cur, llvm::ConstantInt::get(SizeTy, 1),
1162 cur->addIncoming(next, Builder.GetInsertBlock());
1164 // Check whether that's the end of the loop.
1165 llvm::Value *done = Builder.CreateICmpEQ(next, arrayEnd, "arrayctor.done");
1166 llvm::BasicBlock *contBB = createBasicBlock("arrayctor.cont");
1167 Builder.CreateCondBr(done, contBB, loopBB);
1169 // Patch the earlier check to skip over the loop.
1170 if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB);
1175 void CodeGenFunction::destroyCXXObject(CodeGenFunction &CGF,
1178 const RecordType *rtype = type->castAs<RecordType>();
1179 const CXXRecordDecl *record = cast<CXXRecordDecl>(rtype->getDecl());
1180 const CXXDestructorDecl *dtor = record->getDestructor();
1181 assert(!dtor->isTrivial());
1182 CGF.EmitCXXDestructorCall(dtor, Dtor_Complete, /*for vbase*/ false,
1187 CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
1188 CXXCtorType Type, bool ForVirtualBase,
1190 CallExpr::const_arg_iterator ArgBeg,
1191 CallExpr::const_arg_iterator ArgEnd) {
1193 CGDebugInfo *DI = getDebugInfo();
1194 if (DI && CGM.getCodeGenOpts().LimitDebugInfo) {
1195 // If debug info for this class has been emitted then this is the right time
1197 const CXXRecordDecl *Parent = D->getParent();
1198 DI->getOrCreateRecordType(CGM.getContext().getTypeDeclType(Parent),
1199 Parent->getLocation());
1202 if (D->isTrivial()) {
1203 if (ArgBeg == ArgEnd) {
1204 // Trivial default constructor, no codegen required.
1205 assert(D->isDefaultConstructor() &&
1206 "trivial 0-arg ctor not a default ctor");
1210 assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
1211 assert(D->isCopyOrMoveConstructor() &&
1212 "trivial 1-arg ctor not a copy/move ctor");
1214 const Expr *E = (*ArgBeg);
1215 QualType Ty = E->getType();
1216 llvm::Value *Src = EmitLValue(E).getAddress();
1217 EmitAggregateCopy(This, Src, Ty);
1221 llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(D, Type), ForVirtualBase);
1222 llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Type);
1224 EmitCXXMemberCall(D, Callee, ReturnValueSlot(), This, VTT, ArgBeg, ArgEnd);
1228 CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
1229 llvm::Value *This, llvm::Value *Src,
1230 CallExpr::const_arg_iterator ArgBeg,
1231 CallExpr::const_arg_iterator ArgEnd) {
1232 if (D->isTrivial()) {
1233 assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
1234 assert(D->isCopyOrMoveConstructor() &&
1235 "trivial 1-arg ctor not a copy/move ctor");
1236 EmitAggregateCopy(This, Src, (*ArgBeg)->getType());
1239 llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D,
1240 clang::Ctor_Complete);
1241 assert(D->isInstance() &&
1242 "Trying to emit a member call expr on a static method!");
1244 const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
1248 // Push the this ptr.
1249 Args.add(RValue::get(This), D->getThisType(getContext()));
1252 // Push the src ptr.
1253 QualType QT = *(FPT->arg_type_begin());
1254 llvm::Type *t = CGM.getTypes().ConvertType(QT);
1255 Src = Builder.CreateBitCast(Src, t);
1256 Args.add(RValue::get(Src), QT);
1258 // Skip over first argument (Src).
1260 CallExpr::const_arg_iterator Arg = ArgBeg;
1261 for (FunctionProtoType::arg_type_iterator I = FPT->arg_type_begin()+1,
1262 E = FPT->arg_type_end(); I != E; ++I, ++Arg) {
1263 assert(Arg != ArgEnd && "Running over edge of argument list!");
1264 EmitCallArg(Args, *Arg, *I);
1266 // Either we've emitted all the call args, or we have a call to a
1267 // variadic function.
1268 assert((Arg == ArgEnd || FPT->isVariadic()) &&
1269 "Extra arguments in non-variadic function!");
1270 // If we still have any arguments, emit them using the type of the argument.
1271 for (; Arg != ArgEnd; ++Arg) {
1272 QualType ArgType = Arg->getType();
1273 EmitCallArg(Args, *Arg, ArgType);
1276 EmitCall(CGM.getTypes().getFunctionInfo(Args, FPT), Callee,
1277 ReturnValueSlot(), Args, D);
1281 CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
1282 CXXCtorType CtorType,
1283 const FunctionArgList &Args) {
1284 CallArgList DelegateArgs;
1286 FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
1287 assert(I != E && "no parameters to constructor");
1290 DelegateArgs.add(RValue::get(LoadCXXThis()), (*I)->getType());
1294 if (llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(Ctor, CtorType),
1295 /*ForVirtualBase=*/false)) {
1296 QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy);
1297 DelegateArgs.add(RValue::get(VTT), VoidPP);
1299 if (CodeGenVTables::needsVTTParameter(CurGD)) {
1300 assert(I != E && "cannot skip vtt parameter, already done with args");
1301 assert((*I)->getType() == VoidPP && "skipping parameter not of vtt type");
1306 // Explicit arguments.
1307 for (; I != E; ++I) {
1308 const VarDecl *param = *I;
1309 EmitDelegateCallArg(DelegateArgs, param);
1312 EmitCall(CGM.getTypes().getFunctionInfo(Ctor, CtorType),
1313 CGM.GetAddrOfCXXConstructor(Ctor, CtorType),
1314 ReturnValueSlot(), DelegateArgs, Ctor);
1318 struct CallDelegatingCtorDtor : EHScopeStack::Cleanup {
1319 const CXXDestructorDecl *Dtor;
1323 CallDelegatingCtorDtor(const CXXDestructorDecl *D, llvm::Value *Addr,
1325 : Dtor(D), Addr(Addr), Type(Type) {}
1327 void Emit(CodeGenFunction &CGF, Flags flags) {
1328 CGF.EmitCXXDestructorCall(Dtor, Type, /*ForVirtualBase=*/false,
1335 CodeGenFunction::EmitDelegatingCXXConstructorCall(const CXXConstructorDecl *Ctor,
1336 const FunctionArgList &Args) {
1337 assert(Ctor->isDelegatingConstructor());
1339 llvm::Value *ThisPtr = LoadCXXThis();
1341 AggValueSlot AggSlot =
1342 AggValueSlot::forAddr(ThisPtr, Qualifiers(),
1343 AggValueSlot::IsDestructed,
1344 AggValueSlot::DoesNotNeedGCBarriers,
1345 AggValueSlot::IsNotAliased);
1347 EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot);
1349 const CXXRecordDecl *ClassDecl = Ctor->getParent();
1350 if (CGM.getLangOptions().Exceptions && !ClassDecl->hasTrivialDestructor()) {
1352 CurGD.getCtorType() == Ctor_Complete ? Dtor_Complete : Dtor_Base;
1354 EHStack.pushCleanup<CallDelegatingCtorDtor>(EHCleanup,
1355 ClassDecl->getDestructor(),
1360 void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
1362 bool ForVirtualBase,
1363 llvm::Value *This) {
1364 llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(DD, Type),
1366 llvm::Value *Callee = 0;
1367 if (getContext().getLangOptions().AppleKext)
1368 Callee = BuildAppleKextVirtualDestructorCall(DD, Type,
1372 Callee = CGM.GetAddrOfCXXDestructor(DD, Type);
1374 EmitCXXMemberCall(DD, Callee, ReturnValueSlot(), This, VTT, 0, 0);
1378 struct CallLocalDtor : EHScopeStack::Cleanup {
1379 const CXXDestructorDecl *Dtor;
1382 CallLocalDtor(const CXXDestructorDecl *D, llvm::Value *Addr)
1383 : Dtor(D), Addr(Addr) {}
1385 void Emit(CodeGenFunction &CGF, Flags flags) {
1386 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1387 /*ForVirtualBase=*/false, Addr);
1392 void CodeGenFunction::PushDestructorCleanup(const CXXDestructorDecl *D,
1393 llvm::Value *Addr) {
1394 EHStack.pushCleanup<CallLocalDtor>(NormalAndEHCleanup, D, Addr);
1397 void CodeGenFunction::PushDestructorCleanup(QualType T, llvm::Value *Addr) {
1398 CXXRecordDecl *ClassDecl = T->getAsCXXRecordDecl();
1399 if (!ClassDecl) return;
1400 if (ClassDecl->hasTrivialDestructor()) return;
1402 const CXXDestructorDecl *D = ClassDecl->getDestructor();
1403 assert(D && D->isUsed() && "destructor not marked as used!");
1404 PushDestructorCleanup(D, Addr);
1408 CodeGenFunction::GetVirtualBaseClassOffset(llvm::Value *This,
1409 const CXXRecordDecl *ClassDecl,
1410 const CXXRecordDecl *BaseClassDecl) {
1411 llvm::Value *VTablePtr = GetVTablePtr(This, Int8PtrTy);
1412 CharUnits VBaseOffsetOffset =
1413 CGM.getVTableContext().getVirtualBaseOffsetOffset(ClassDecl, BaseClassDecl);
1415 llvm::Value *VBaseOffsetPtr =
1416 Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset.getQuantity(),
1417 "vbase.offset.ptr");
1418 llvm::Type *PtrDiffTy =
1419 ConvertType(getContext().getPointerDiffType());
1421 VBaseOffsetPtr = Builder.CreateBitCast(VBaseOffsetPtr,
1422 PtrDiffTy->getPointerTo());
1424 llvm::Value *VBaseOffset = Builder.CreateLoad(VBaseOffsetPtr, "vbase.offset");
1430 CodeGenFunction::InitializeVTablePointer(BaseSubobject Base,
1431 const CXXRecordDecl *NearestVBase,
1432 CharUnits OffsetFromNearestVBase,
1433 llvm::Constant *VTable,
1434 const CXXRecordDecl *VTableClass) {
1435 const CXXRecordDecl *RD = Base.getBase();
1437 // Compute the address point.
1438 llvm::Value *VTableAddressPoint;
1440 // Check if we need to use a vtable from the VTT.
1441 if (CodeGenVTables::needsVTTParameter(CurGD) &&
1442 (RD->getNumVBases() || NearestVBase)) {
1443 // Get the secondary vpointer index.
1444 uint64_t VirtualPointerIndex =
1445 CGM.getVTables().getSecondaryVirtualPointerIndex(VTableClass, Base);
1448 llvm::Value *VTT = LoadCXXVTT();
1449 if (VirtualPointerIndex)
1450 VTT = Builder.CreateConstInBoundsGEP1_64(VTT, VirtualPointerIndex);
1452 // And load the address point from the VTT.
1453 VTableAddressPoint = Builder.CreateLoad(VTT);
1455 uint64_t AddressPoint =
1456 CGM.getVTableContext().getVTableLayout(VTableClass).getAddressPoint(Base);
1457 VTableAddressPoint =
1458 Builder.CreateConstInBoundsGEP2_64(VTable, 0, AddressPoint);
1461 // Compute where to store the address point.
1462 llvm::Value *VirtualOffset = 0;
1463 CharUnits NonVirtualOffset = CharUnits::Zero();
1465 if (CodeGenVTables::needsVTTParameter(CurGD) && NearestVBase) {
1466 // We need to use the virtual base offset offset because the virtual base
1467 // might have a different offset in the most derived class.
1468 VirtualOffset = GetVirtualBaseClassOffset(LoadCXXThis(), VTableClass,
1470 NonVirtualOffset = OffsetFromNearestVBase;
1472 // We can just use the base offset in the complete class.
1473 NonVirtualOffset = Base.getBaseOffset();
1476 // Apply the offsets.
1477 llvm::Value *VTableField = LoadCXXThis();
1479 if (!NonVirtualOffset.isZero() || VirtualOffset)
1480 VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField,
1484 // Finally, store the address point.
1485 llvm::Type *AddressPointPtrTy =
1486 VTableAddressPoint->getType()->getPointerTo();
1487 VTableField = Builder.CreateBitCast(VTableField, AddressPointPtrTy);
1488 Builder.CreateStore(VTableAddressPoint, VTableField);
1492 CodeGenFunction::InitializeVTablePointers(BaseSubobject Base,
1493 const CXXRecordDecl *NearestVBase,
1494 CharUnits OffsetFromNearestVBase,
1495 bool BaseIsNonVirtualPrimaryBase,
1496 llvm::Constant *VTable,
1497 const CXXRecordDecl *VTableClass,
1498 VisitedVirtualBasesSetTy& VBases) {
1499 // If this base is a non-virtual primary base the address point has already
1501 if (!BaseIsNonVirtualPrimaryBase) {
1502 // Initialize the vtable pointer for this base.
1503 InitializeVTablePointer(Base, NearestVBase, OffsetFromNearestVBase,
1504 VTable, VTableClass);
1507 const CXXRecordDecl *RD = Base.getBase();
1510 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
1511 E = RD->bases_end(); I != E; ++I) {
1512 CXXRecordDecl *BaseDecl
1513 = cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
1515 // Ignore classes without a vtable.
1516 if (!BaseDecl->isDynamicClass())
1519 CharUnits BaseOffset;
1520 CharUnits BaseOffsetFromNearestVBase;
1521 bool BaseDeclIsNonVirtualPrimaryBase;
1523 if (I->isVirtual()) {
1524 // Check if we've visited this virtual base before.
1525 if (!VBases.insert(BaseDecl))
1528 const ASTRecordLayout &Layout =
1529 getContext().getASTRecordLayout(VTableClass);
1531 BaseOffset = Layout.getVBaseClassOffset(BaseDecl);
1532 BaseOffsetFromNearestVBase = CharUnits::Zero();
1533 BaseDeclIsNonVirtualPrimaryBase = false;
1535 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1537 BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl);
1538 BaseOffsetFromNearestVBase =
1539 OffsetFromNearestVBase + Layout.getBaseClassOffset(BaseDecl);
1540 BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl;
1543 InitializeVTablePointers(BaseSubobject(BaseDecl, BaseOffset),
1544 I->isVirtual() ? BaseDecl : NearestVBase,
1545 BaseOffsetFromNearestVBase,
1546 BaseDeclIsNonVirtualPrimaryBase,
1547 VTable, VTableClass, VBases);
1551 void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
1552 // Ignore classes without a vtable.
1553 if (!RD->isDynamicClass())
1557 llvm::Constant *VTable = CGM.getVTables().GetAddrOfVTable(RD);
1559 // Initialize the vtable pointers for this class and all of its bases.
1560 VisitedVirtualBasesSetTy VBases;
1561 InitializeVTablePointers(BaseSubobject(RD, CharUnits::Zero()),
1563 /*OffsetFromNearestVBase=*/CharUnits::Zero(),
1564 /*BaseIsNonVirtualPrimaryBase=*/false,
1565 VTable, RD, VBases);
1568 llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
1570 llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo());
1571 return Builder.CreateLoad(VTablePtrSrc, "vtable");
1574 static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) {
1575 const Expr *E = Base;
1578 E = E->IgnoreParens();
1579 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
1580 if (CE->getCastKind() == CK_DerivedToBase ||
1581 CE->getCastKind() == CK_UncheckedDerivedToBase ||
1582 CE->getCastKind() == CK_NoOp) {
1583 E = CE->getSubExpr();
1591 QualType DerivedType = E->getType();
1592 if (const PointerType *PTy = DerivedType->getAs<PointerType>())
1593 DerivedType = PTy->getPointeeType();
1595 return cast<CXXRecordDecl>(DerivedType->castAs<RecordType>()->getDecl());
1598 // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do
1599 // quite what we want.
1600 static const Expr *skipNoOpCastsAndParens(const Expr *E) {
1602 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
1603 E = PE->getSubExpr();
1607 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
1608 if (CE->getCastKind() == CK_NoOp) {
1609 E = CE->getSubExpr();
1613 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
1614 if (UO->getOpcode() == UO_Extension) {
1615 E = UO->getSubExpr();
1623 /// canDevirtualizeMemberFunctionCall - Checks whether the given virtual member
1624 /// function call on the given expr can be devirtualized.
1625 static bool canDevirtualizeMemberFunctionCall(const Expr *Base,
1626 const CXXMethodDecl *MD) {
1627 // If the most derived class is marked final, we know that no subclass can
1628 // override this member function and so we can devirtualize it. For example:
1630 // struct A { virtual void f(); }
1631 // struct B final : A { };
1637 const CXXRecordDecl *MostDerivedClassDecl = getMostDerivedClassDecl(Base);
1638 if (MostDerivedClassDecl->hasAttr<FinalAttr>())
1641 // If the member function is marked 'final', we know that it can't be
1642 // overridden and can therefore devirtualize it.
1643 if (MD->hasAttr<FinalAttr>())
1646 // Similarly, if the class itself is marked 'final' it can't be overridden
1647 // and we can therefore devirtualize the member function call.
1648 if (MD->getParent()->hasAttr<FinalAttr>())
1651 Base = skipNoOpCastsAndParens(Base);
1652 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
1653 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
1654 // This is a record decl. We know the type and can devirtualize it.
1655 return VD->getType()->isRecordType();
1661 // We can always devirtualize calls on temporary object expressions.
1662 if (isa<CXXConstructExpr>(Base))
1665 // And calls on bound temporaries.
1666 if (isa<CXXBindTemporaryExpr>(Base))
1669 // Check if this is a call expr that returns a record type.
1670 if (const CallExpr *CE = dyn_cast<CallExpr>(Base))
1671 return CE->getCallReturnType()->isRecordType();
1673 // We can't devirtualize the call.
1677 static bool UseVirtualCall(ASTContext &Context,
1678 const CXXOperatorCallExpr *CE,
1679 const CXXMethodDecl *MD) {
1680 if (!MD->isVirtual())
1683 // When building with -fapple-kext, all calls must go through the vtable since
1684 // the kernel linker can do runtime patching of vtables.
1685 if (Context.getLangOptions().AppleKext)
1688 return !canDevirtualizeMemberFunctionCall(CE->getArg(0), MD);
1692 CodeGenFunction::EmitCXXOperatorMemberCallee(const CXXOperatorCallExpr *E,
1693 const CXXMethodDecl *MD,
1694 llvm::Value *This) {
1695 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1697 CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
1700 if (UseVirtualCall(getContext(), E, MD))
1701 return BuildVirtualCall(MD, This, Ty);
1703 return CGM.GetAddrOfFunction(MD, Ty);