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 //===----------------------------------------------------------------------===//
15 #include "CGDebugInfo.h"
16 #include "CGRecordLayout.h"
17 #include "CodeGenFunction.h"
19 #include "clang/AST/CXXInheritance.h"
20 #include "clang/AST/DeclTemplate.h"
21 #include "clang/AST/EvaluatedExprVisitor.h"
22 #include "clang/AST/RecordLayout.h"
23 #include "clang/AST/StmtCXX.h"
24 #include "clang/Basic/TargetBuiltins.h"
25 #include "clang/CodeGen/CGFunctionInfo.h"
26 #include "clang/Frontend/CodeGenOptions.h"
28 using namespace clang;
29 using namespace CodeGen;
32 ComputeNonVirtualBaseClassOffset(ASTContext &Context,
33 const CXXRecordDecl *DerivedClass,
34 CastExpr::path_const_iterator Start,
35 CastExpr::path_const_iterator End) {
36 CharUnits Offset = CharUnits::Zero();
38 const CXXRecordDecl *RD = DerivedClass;
40 for (CastExpr::path_const_iterator I = Start; I != End; ++I) {
41 const CXXBaseSpecifier *Base = *I;
42 assert(!Base->isVirtual() && "Should not see virtual bases here!");
45 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
47 const CXXRecordDecl *BaseDecl =
48 cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
51 Offset += Layout.getBaseClassOffset(BaseDecl);
60 CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
61 CastExpr::path_const_iterator PathBegin,
62 CastExpr::path_const_iterator PathEnd) {
63 assert(PathBegin != PathEnd && "Base path should not be empty!");
66 ComputeNonVirtualBaseClassOffset(getContext(), ClassDecl,
71 llvm::Type *PtrDiffTy =
72 Types.ConvertType(getContext().getPointerDiffType());
74 return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity());
77 /// Gets the address of a direct base class within a complete object.
78 /// This should only be used for (1) non-virtual bases or (2) virtual bases
79 /// when the type is known to be complete (e.g. in complete destructors).
81 /// The object pointed to by 'This' is assumed to be non-null.
83 CodeGenFunction::GetAddressOfDirectBaseInCompleteClass(llvm::Value *This,
84 const CXXRecordDecl *Derived,
85 const CXXRecordDecl *Base,
87 // 'this' must be a pointer (in some address space) to Derived.
88 assert(This->getType()->isPointerTy() &&
89 cast<llvm::PointerType>(This->getType())->getElementType()
90 == ConvertType(Derived));
92 // Compute the offset of the virtual base.
94 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
96 Offset = Layout.getVBaseClassOffset(Base);
98 Offset = Layout.getBaseClassOffset(Base);
100 // Shift and cast down to the base type.
101 // TODO: for complete types, this should be possible with a GEP.
102 llvm::Value *V = This;
103 if (Offset.isPositive()) {
104 V = Builder.CreateBitCast(V, Int8PtrTy);
105 V = Builder.CreateConstInBoundsGEP1_64(V, Offset.getQuantity());
107 V = Builder.CreateBitCast(V, ConvertType(Base)->getPointerTo());
113 ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, llvm::Value *ptr,
114 CharUnits nonVirtualOffset,
115 llvm::Value *virtualOffset) {
116 // Assert that we have something to do.
117 assert(!nonVirtualOffset.isZero() || virtualOffset != 0);
119 // Compute the offset from the static and dynamic components.
120 llvm::Value *baseOffset;
121 if (!nonVirtualOffset.isZero()) {
122 baseOffset = llvm::ConstantInt::get(CGF.PtrDiffTy,
123 nonVirtualOffset.getQuantity());
125 baseOffset = CGF.Builder.CreateAdd(virtualOffset, baseOffset);
128 baseOffset = virtualOffset;
131 // Apply the base offset.
132 ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8PtrTy);
133 ptr = CGF.Builder.CreateInBoundsGEP(ptr, baseOffset, "add.ptr");
138 CodeGenFunction::GetAddressOfBaseClass(llvm::Value *Value,
139 const CXXRecordDecl *Derived,
140 CastExpr::path_const_iterator PathBegin,
141 CastExpr::path_const_iterator PathEnd,
142 bool NullCheckValue) {
143 assert(PathBegin != PathEnd && "Base path should not be empty!");
145 CastExpr::path_const_iterator Start = PathBegin;
146 const CXXRecordDecl *VBase = 0;
148 // Sema has done some convenient canonicalization here: if the
149 // access path involved any virtual steps, the conversion path will
150 // *start* with a step down to the correct virtual base subobject,
151 // and hence will not require any further steps.
152 if ((*Start)->isVirtual()) {
154 cast<CXXRecordDecl>((*Start)->getType()->getAs<RecordType>()->getDecl());
158 // Compute the static offset of the ultimate destination within its
159 // allocating subobject (the virtual base, if there is one, or else
160 // the "complete" object that we see).
161 CharUnits NonVirtualOffset =
162 ComputeNonVirtualBaseClassOffset(getContext(), VBase ? VBase : Derived,
165 // If there's a virtual step, we can sometimes "devirtualize" it.
166 // For now, that's limited to when the derived type is final.
167 // TODO: "devirtualize" this for accesses to known-complete objects.
168 if (VBase && Derived->hasAttr<FinalAttr>()) {
169 const ASTRecordLayout &layout = getContext().getASTRecordLayout(Derived);
170 CharUnits vBaseOffset = layout.getVBaseClassOffset(VBase);
171 NonVirtualOffset += vBaseOffset;
172 VBase = 0; // we no longer have a virtual step
175 // Get the base pointer type.
176 llvm::Type *BasePtrTy =
177 ConvertType((PathEnd[-1])->getType())->getPointerTo();
179 // If the static offset is zero and we don't have a virtual step,
180 // just do a bitcast; null checks are unnecessary.
181 if (NonVirtualOffset.isZero() && !VBase) {
182 return Builder.CreateBitCast(Value, BasePtrTy);
185 llvm::BasicBlock *origBB = 0;
186 llvm::BasicBlock *endBB = 0;
188 // Skip over the offset (and the vtable load) if we're supposed to
189 // null-check the pointer.
190 if (NullCheckValue) {
191 origBB = Builder.GetInsertBlock();
192 llvm::BasicBlock *notNullBB = createBasicBlock("cast.notnull");
193 endBB = createBasicBlock("cast.end");
195 llvm::Value *isNull = Builder.CreateIsNull(Value);
196 Builder.CreateCondBr(isNull, endBB, notNullBB);
197 EmitBlock(notNullBB);
200 // Compute the virtual offset.
201 llvm::Value *VirtualOffset = 0;
204 CGM.getCXXABI().GetVirtualBaseClassOffset(*this, Value, Derived, VBase);
207 // Apply both offsets.
208 Value = ApplyNonVirtualAndVirtualOffset(*this, Value,
212 // Cast to the destination type.
213 Value = Builder.CreateBitCast(Value, BasePtrTy);
215 // Build a phi if we needed a null check.
216 if (NullCheckValue) {
217 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
218 Builder.CreateBr(endBB);
221 llvm::PHINode *PHI = Builder.CreatePHI(BasePtrTy, 2, "cast.result");
222 PHI->addIncoming(Value, notNullBB);
223 PHI->addIncoming(llvm::Constant::getNullValue(BasePtrTy), origBB);
231 CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value,
232 const CXXRecordDecl *Derived,
233 CastExpr::path_const_iterator PathBegin,
234 CastExpr::path_const_iterator PathEnd,
235 bool NullCheckValue) {
236 assert(PathBegin != PathEnd && "Base path should not be empty!");
239 getContext().getCanonicalType(getContext().getTagDeclType(Derived));
240 llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
242 llvm::Value *NonVirtualOffset =
243 CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
245 if (!NonVirtualOffset) {
246 // No offset, we can just cast back.
247 return Builder.CreateBitCast(Value, DerivedPtrTy);
250 llvm::BasicBlock *CastNull = 0;
251 llvm::BasicBlock *CastNotNull = 0;
252 llvm::BasicBlock *CastEnd = 0;
254 if (NullCheckValue) {
255 CastNull = createBasicBlock("cast.null");
256 CastNotNull = createBasicBlock("cast.notnull");
257 CastEnd = createBasicBlock("cast.end");
259 llvm::Value *IsNull = Builder.CreateIsNull(Value);
260 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
261 EmitBlock(CastNotNull);
265 Value = Builder.CreateBitCast(Value, Int8PtrTy);
266 Value = Builder.CreateGEP(Value, Builder.CreateNeg(NonVirtualOffset),
270 Value = Builder.CreateBitCast(Value, DerivedPtrTy);
272 if (NullCheckValue) {
273 Builder.CreateBr(CastEnd);
275 Builder.CreateBr(CastEnd);
278 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
279 PHI->addIncoming(Value, CastNotNull);
280 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
288 llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD,
291 if (!CGM.getCXXABI().NeedsVTTParameter(GD)) {
292 // This constructor/destructor does not need a VTT parameter.
296 const CXXRecordDecl *RD = cast<CXXMethodDecl>(CurCodeDecl)->getParent();
297 const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent();
301 uint64_t SubVTTIndex;
304 // If this is a delegating constructor call, just load the VTT.
306 } else if (RD == Base) {
307 // If the record matches the base, this is the complete ctor/dtor
308 // variant calling the base variant in a class with virtual bases.
309 assert(!CGM.getCXXABI().NeedsVTTParameter(CurGD) &&
310 "doing no-op VTT offset in base dtor/ctor?");
311 assert(!ForVirtualBase && "Can't have same class as virtual base!");
314 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
315 CharUnits BaseOffset = ForVirtualBase ?
316 Layout.getVBaseClassOffset(Base) :
317 Layout.getBaseClassOffset(Base);
320 CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset));
321 assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
324 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
325 // A VTT parameter was passed to the constructor, use it.
327 VTT = Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex);
329 // We're the complete constructor, so get the VTT by name.
330 VTT = CGM.getVTables().GetAddrOfVTT(RD);
331 VTT = Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
338 /// Call the destructor for a direct base class.
339 struct CallBaseDtor : EHScopeStack::Cleanup {
340 const CXXRecordDecl *BaseClass;
342 CallBaseDtor(const CXXRecordDecl *Base, bool BaseIsVirtual)
343 : BaseClass(Base), BaseIsVirtual(BaseIsVirtual) {}
345 void Emit(CodeGenFunction &CGF, Flags flags) {
346 const CXXRecordDecl *DerivedClass =
347 cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent();
349 const CXXDestructorDecl *D = BaseClass->getDestructor();
351 CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThis(),
352 DerivedClass, BaseClass,
354 CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual,
355 /*Delegating=*/false, Addr);
359 /// A visitor which checks whether an initializer uses 'this' in a
360 /// way which requires the vtable to be properly set.
361 struct DynamicThisUseChecker : EvaluatedExprVisitor<DynamicThisUseChecker> {
362 typedef EvaluatedExprVisitor<DynamicThisUseChecker> super;
366 DynamicThisUseChecker(ASTContext &C) : super(C), UsesThis(false) {}
368 // Black-list all explicit and implicit references to 'this'.
370 // Do we need to worry about external references to 'this' derived
371 // from arbitrary code? If so, then anything which runs arbitrary
372 // external code might potentially access the vtable.
373 void VisitCXXThisExpr(CXXThisExpr *E) { UsesThis = true; }
377 static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
378 DynamicThisUseChecker Checker(C);
379 Checker.Visit(const_cast<Expr*>(Init));
380 return Checker.UsesThis;
383 static void EmitBaseInitializer(CodeGenFunction &CGF,
384 const CXXRecordDecl *ClassDecl,
385 CXXCtorInitializer *BaseInit,
386 CXXCtorType CtorType) {
387 assert(BaseInit->isBaseInitializer() &&
388 "Must have base initializer!");
390 llvm::Value *ThisPtr = CGF.LoadCXXThis();
392 const Type *BaseType = BaseInit->getBaseClass();
393 CXXRecordDecl *BaseClassDecl =
394 cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
396 bool isBaseVirtual = BaseInit->isBaseVirtual();
398 // The base constructor doesn't construct virtual bases.
399 if (CtorType == Ctor_Base && isBaseVirtual)
402 // If the initializer for the base (other than the constructor
403 // itself) accesses 'this' in any way, we need to initialize the
405 if (BaseInitializerUsesThis(CGF.getContext(), BaseInit->getInit()))
406 CGF.InitializeVTablePointers(ClassDecl);
408 // We can pretend to be a complete class because it only matters for
409 // virtual bases, and we only do virtual bases for complete ctors.
411 CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl,
414 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(BaseType);
415 AggValueSlot AggSlot =
416 AggValueSlot::forAddr(V, Alignment, Qualifiers(),
417 AggValueSlot::IsDestructed,
418 AggValueSlot::DoesNotNeedGCBarriers,
419 AggValueSlot::IsNotAliased);
421 CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
423 if (CGF.CGM.getLangOpts().Exceptions &&
424 !BaseClassDecl->hasTrivialDestructor())
425 CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
429 static void EmitAggMemberInitializer(CodeGenFunction &CGF,
432 llvm::Value *ArrayIndexVar,
434 ArrayRef<VarDecl *> ArrayIndexes,
436 if (Index == ArrayIndexes.size()) {
440 // If we have an array index variable, load it and use it as an offset.
441 // Then, increment the value.
442 llvm::Value *Dest = LHS.getAddress();
443 llvm::Value *ArrayIndex = CGF.Builder.CreateLoad(ArrayIndexVar);
444 Dest = CGF.Builder.CreateInBoundsGEP(Dest, ArrayIndex, "destaddress");
445 llvm::Value *Next = llvm::ConstantInt::get(ArrayIndex->getType(), 1);
446 Next = CGF.Builder.CreateAdd(ArrayIndex, Next, "inc");
447 CGF.Builder.CreateStore(Next, ArrayIndexVar);
449 // Update the LValue.
451 CharUnits Align = CGF.getContext().getTypeAlignInChars(T);
452 LV.setAlignment(std::min(Align, LV.getAlignment()));
455 switch (CGF.getEvaluationKind(T)) {
457 CGF.EmitScalarInit(Init, /*decl*/ 0, LV, false);
460 CGF.EmitComplexExprIntoLValue(Init, LV, /*isInit*/ true);
462 case TEK_Aggregate: {
464 AggValueSlot::forLValue(LV,
465 AggValueSlot::IsDestructed,
466 AggValueSlot::DoesNotNeedGCBarriers,
467 AggValueSlot::IsNotAliased);
469 CGF.EmitAggExpr(Init, Slot);
477 const ConstantArrayType *Array = CGF.getContext().getAsConstantArrayType(T);
478 assert(Array && "Array initialization without the array type?");
479 llvm::Value *IndexVar
480 = CGF.GetAddrOfLocalVar(ArrayIndexes[Index]);
481 assert(IndexVar && "Array index variable not loaded");
483 // Initialize this index variable to zero.
485 = llvm::Constant::getNullValue(
486 CGF.ConvertType(CGF.getContext().getSizeType()));
487 CGF.Builder.CreateStore(Zero, IndexVar);
489 // Start the loop with a block that tests the condition.
490 llvm::BasicBlock *CondBlock = CGF.createBasicBlock("for.cond");
491 llvm::BasicBlock *AfterFor = CGF.createBasicBlock("for.end");
493 CGF.EmitBlock(CondBlock);
495 llvm::BasicBlock *ForBody = CGF.createBasicBlock("for.body");
496 // Generate: if (loop-index < number-of-elements) fall to the loop body,
497 // otherwise, go to the block after the for-loop.
498 uint64_t NumElements = Array->getSize().getZExtValue();
499 llvm::Value *Counter = CGF.Builder.CreateLoad(IndexVar);
500 llvm::Value *NumElementsPtr =
501 llvm::ConstantInt::get(Counter->getType(), NumElements);
502 llvm::Value *IsLess = CGF.Builder.CreateICmpULT(Counter, NumElementsPtr,
505 // If the condition is true, execute the body.
506 CGF.Builder.CreateCondBr(IsLess, ForBody, AfterFor);
508 CGF.EmitBlock(ForBody);
509 llvm::BasicBlock *ContinueBlock = CGF.createBasicBlock("for.inc");
511 // Inside the loop body recurse to emit the inner loop or, eventually, the
513 EmitAggMemberInitializer(CGF, LHS, Init, ArrayIndexVar,
514 Array->getElementType(), ArrayIndexes, Index + 1);
516 CGF.EmitBlock(ContinueBlock);
518 // Emit the increment of the loop counter.
519 llvm::Value *NextVal = llvm::ConstantInt::get(Counter->getType(), 1);
520 Counter = CGF.Builder.CreateLoad(IndexVar);
521 NextVal = CGF.Builder.CreateAdd(Counter, NextVal, "inc");
522 CGF.Builder.CreateStore(NextVal, IndexVar);
524 // Finally, branch back up to the condition for the next iteration.
525 CGF.EmitBranch(CondBlock);
527 // Emit the fall-through block.
528 CGF.EmitBlock(AfterFor, true);
531 static void EmitMemberInitializer(CodeGenFunction &CGF,
532 const CXXRecordDecl *ClassDecl,
533 CXXCtorInitializer *MemberInit,
534 const CXXConstructorDecl *Constructor,
535 FunctionArgList &Args) {
536 assert(MemberInit->isAnyMemberInitializer() &&
537 "Must have member initializer!");
538 assert(MemberInit->getInit() && "Must have initializer!");
540 // non-static data member initializers.
541 FieldDecl *Field = MemberInit->getAnyMember();
542 QualType FieldType = Field->getType();
544 llvm::Value *ThisPtr = CGF.LoadCXXThis();
545 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
546 LValue LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
548 if (MemberInit->isIndirectMemberInitializer()) {
549 // If we are initializing an anonymous union field, drill down to
551 IndirectFieldDecl *IndirectField = MemberInit->getIndirectMember();
552 IndirectFieldDecl::chain_iterator I = IndirectField->chain_begin(),
553 IEnd = IndirectField->chain_end();
554 for ( ; I != IEnd; ++I)
555 LHS = CGF.EmitLValueForFieldInitialization(LHS, cast<FieldDecl>(*I));
556 FieldType = MemberInit->getIndirectMember()->getAnonField()->getType();
558 LHS = CGF.EmitLValueForFieldInitialization(LHS, Field);
561 // Special case: if we are in a copy or move constructor, and we are copying
562 // an array of PODs or classes with trivial copy constructors, ignore the
563 // AST and perform the copy we know is equivalent.
564 // FIXME: This is hacky at best... if we had a bit more explicit information
565 // in the AST, we could generalize it more easily.
566 const ConstantArrayType *Array
567 = CGF.getContext().getAsConstantArrayType(FieldType);
568 if (Array && Constructor->isDefaulted() &&
569 Constructor->isCopyOrMoveConstructor()) {
570 QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
571 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
572 if (BaseElementTy.isPODType(CGF.getContext()) ||
573 (CE && CE->getConstructor()->isTrivial())) {
574 // Find the source pointer. We know it's the last argument because
575 // we know we're in an implicit copy constructor.
576 unsigned SrcArgIndex = Args.size() - 1;
578 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
579 LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
580 LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV, Field);
582 // Copy the aggregate.
583 CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType,
584 LHS.isVolatileQualified());
589 ArrayRef<VarDecl *> ArrayIndexes;
590 if (MemberInit->getNumArrayIndices())
591 ArrayIndexes = MemberInit->getArrayIndexes();
592 CGF.EmitInitializerForField(Field, LHS, MemberInit->getInit(), ArrayIndexes);
595 void CodeGenFunction::EmitInitializerForField(FieldDecl *Field,
596 LValue LHS, Expr *Init,
597 ArrayRef<VarDecl *> ArrayIndexes) {
598 QualType FieldType = Field->getType();
599 switch (getEvaluationKind(FieldType)) {
601 if (LHS.isSimple()) {
602 EmitExprAsInit(Init, Field, LHS, false);
604 RValue RHS = RValue::get(EmitScalarExpr(Init));
605 EmitStoreThroughLValue(RHS, LHS);
609 EmitComplexExprIntoLValue(Init, LHS, /*isInit*/ true);
611 case TEK_Aggregate: {
612 llvm::Value *ArrayIndexVar = 0;
613 if (ArrayIndexes.size()) {
614 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
616 // The LHS is a pointer to the first object we'll be constructing, as
618 QualType BaseElementTy = getContext().getBaseElementType(FieldType);
619 llvm::Type *BasePtr = ConvertType(BaseElementTy);
620 BasePtr = llvm::PointerType::getUnqual(BasePtr);
621 llvm::Value *BaseAddrPtr = Builder.CreateBitCast(LHS.getAddress(),
623 LHS = MakeAddrLValue(BaseAddrPtr, BaseElementTy);
625 // Create an array index that will be used to walk over all of the
626 // objects we're constructing.
627 ArrayIndexVar = CreateTempAlloca(SizeTy, "object.index");
628 llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy);
629 Builder.CreateStore(Zero, ArrayIndexVar);
632 // Emit the block variables for the array indices, if any.
633 for (unsigned I = 0, N = ArrayIndexes.size(); I != N; ++I)
634 EmitAutoVarDecl(*ArrayIndexes[I]);
637 EmitAggMemberInitializer(*this, LHS, Init, ArrayIndexVar, FieldType,
642 // Ensure that we destroy this object if an exception is thrown
643 // later in the constructor.
644 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
645 if (needsEHCleanup(dtorKind))
646 pushEHDestroy(dtorKind, LHS.getAddress(), FieldType);
649 /// Checks whether the given constructor is a valid subject for the
650 /// complete-to-base constructor delegation optimization, i.e.
651 /// emitting the complete constructor as a simple call to the base
653 static bool IsConstructorDelegationValid(const CXXConstructorDecl *Ctor) {
655 // Currently we disable the optimization for classes with virtual
656 // bases because (1) the addresses of parameter variables need to be
657 // consistent across all initializers but (2) the delegate function
658 // call necessarily creates a second copy of the parameter variable.
660 // The limiting example (purely theoretical AFAIK):
661 // struct A { A(int &c) { c++; } };
662 // struct B : virtual A {
663 // B(int count) : A(count) { printf("%d\n", count); }
665 // ...although even this example could in principle be emitted as a
666 // delegation since the address of the parameter doesn't escape.
667 if (Ctor->getParent()->getNumVBases()) {
668 // TODO: white-list trivial vbase initializers. This case wouldn't
669 // be subject to the restrictions below.
671 // TODO: white-list cases where:
672 // - there are no non-reference parameters to the constructor
673 // - the initializers don't access any non-reference parameters
674 // - the initializers don't take the address of non-reference
677 // If we ever add any of the above cases, remember that:
678 // - function-try-blocks will always blacklist this optimization
679 // - we need to perform the constructor prologue and cleanup in
680 // EmitConstructorBody.
685 // We also disable the optimization for variadic functions because
686 // it's impossible to "re-pass" varargs.
687 if (Ctor->getType()->getAs<FunctionProtoType>()->isVariadic())
690 // FIXME: Decide if we can do a delegation of a delegating constructor.
691 if (Ctor->isDelegatingConstructor())
697 /// EmitConstructorBody - Emits the body of the current constructor.
698 void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
699 const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
700 CXXCtorType CtorType = CurGD.getCtorType();
702 // Before we go any further, try the complete->base constructor
703 // delegation optimization.
704 if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor) &&
705 CGM.getTarget().getCXXABI().hasConstructorVariants()) {
706 if (CGDebugInfo *DI = getDebugInfo())
707 DI->EmitLocation(Builder, Ctor->getLocEnd());
708 EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args, Ctor->getLocEnd());
712 Stmt *Body = Ctor->getBody();
714 // Enter the function-try-block before the constructor prologue if
716 bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
718 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
720 RunCleanupsScope RunCleanups(*this);
722 // TODO: in restricted cases, we can emit the vbase initializers of
723 // a complete ctor and then delegate to the base ctor.
725 // Emit the constructor prologue, i.e. the base and member
727 EmitCtorPrologue(Ctor, CtorType, Args);
729 // Emit the body of the statement.
731 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
735 // Emit any cleanup blocks associated with the member or base
736 // initializers, which includes (along the exceptional path) the
737 // destructors for those members and bases that were fully
739 RunCleanups.ForceCleanup();
742 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
746 /// RAII object to indicate that codegen is copying the value representation
747 /// instead of the object representation. Useful when copying a struct or
748 /// class which has uninitialized members and we're only performing
749 /// lvalue-to-rvalue conversion on the object but not its members.
750 class CopyingValueRepresentation {
752 explicit CopyingValueRepresentation(CodeGenFunction &CGF)
753 : CGF(CGF), SO(*CGF.SanOpts), OldSanOpts(CGF.SanOpts) {
758 ~CopyingValueRepresentation() {
759 CGF.SanOpts = OldSanOpts;
762 CodeGenFunction &CGF;
764 const SanitizerOptions *OldSanOpts;
769 class FieldMemcpyizer {
771 FieldMemcpyizer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl,
772 const VarDecl *SrcRec)
773 : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec),
774 RecLayout(CGF.getContext().getASTRecordLayout(ClassDecl)),
775 FirstField(0), LastField(0), FirstFieldOffset(0), LastFieldOffset(0),
776 LastAddedFieldIndex(0) { }
778 static bool isMemcpyableField(FieldDecl *F) {
779 Qualifiers Qual = F->getType().getQualifiers();
780 if (Qual.hasVolatile() || Qual.hasObjCLifetime())
785 void addMemcpyableField(FieldDecl *F) {
792 CharUnits getMemcpySize() const {
793 unsigned LastFieldSize =
794 LastField->isBitField() ?
795 LastField->getBitWidthValue(CGF.getContext()) :
796 CGF.getContext().getTypeSize(LastField->getType());
797 uint64_t MemcpySizeBits =
798 LastFieldOffset + LastFieldSize - FirstFieldOffset +
799 CGF.getContext().getCharWidth() - 1;
800 CharUnits MemcpySize =
801 CGF.getContext().toCharUnitsFromBits(MemcpySizeBits);
806 // Give the subclass a chance to bail out if it feels the memcpy isn't
807 // worth it (e.g. Hasn't aggregated enough data).
808 if (FirstField == 0) {
814 if (FirstField->isBitField()) {
815 const CGRecordLayout &RL =
816 CGF.getTypes().getCGRecordLayout(FirstField->getParent());
817 const CGBitFieldInfo &BFInfo = RL.getBitFieldInfo(FirstField);
818 Alignment = CharUnits::fromQuantity(BFInfo.StorageAlignment);
820 Alignment = CGF.getContext().getDeclAlign(FirstField);
823 assert((CGF.getContext().toCharUnitsFromBits(FirstFieldOffset) %
824 Alignment) == 0 && "Bad field alignment.");
826 CharUnits MemcpySize = getMemcpySize();
827 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
828 llvm::Value *ThisPtr = CGF.LoadCXXThis();
829 LValue DestLV = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
830 LValue Dest = CGF.EmitLValueForFieldInitialization(DestLV, FirstField);
831 llvm::Value *SrcPtr = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(SrcRec));
832 LValue SrcLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
833 LValue Src = CGF.EmitLValueForFieldInitialization(SrcLV, FirstField);
835 emitMemcpyIR(Dest.isBitField() ? Dest.getBitFieldAddr() : Dest.getAddress(),
836 Src.isBitField() ? Src.getBitFieldAddr() : Src.getAddress(),
837 MemcpySize, Alignment);
846 CodeGenFunction &CGF;
847 const CXXRecordDecl *ClassDecl;
851 void emitMemcpyIR(llvm::Value *DestPtr, llvm::Value *SrcPtr,
852 CharUnits Size, CharUnits Alignment) {
853 llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
855 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), DPT->getAddressSpace());
856 DestPtr = CGF.Builder.CreateBitCast(DestPtr, DBP);
858 llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
860 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), SPT->getAddressSpace());
861 SrcPtr = CGF.Builder.CreateBitCast(SrcPtr, SBP);
863 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity(),
864 Alignment.getQuantity());
867 void addInitialField(FieldDecl *F) {
870 FirstFieldOffset = RecLayout.getFieldOffset(F->getFieldIndex());
871 LastFieldOffset = FirstFieldOffset;
872 LastAddedFieldIndex = F->getFieldIndex();
876 void addNextField(FieldDecl *F) {
877 // For the most part, the following invariant will hold:
878 // F->getFieldIndex() == LastAddedFieldIndex + 1
879 // The one exception is that Sema won't add a copy-initializer for an
880 // unnamed bitfield, which will show up here as a gap in the sequence.
881 assert(F->getFieldIndex() >= LastAddedFieldIndex + 1 &&
882 "Cannot aggregate fields out of order.");
883 LastAddedFieldIndex = F->getFieldIndex();
885 // The 'first' and 'last' fields are chosen by offset, rather than field
886 // index. This allows the code to support bitfields, as well as regular
888 uint64_t FOffset = RecLayout.getFieldOffset(F->getFieldIndex());
889 if (FOffset < FirstFieldOffset) {
891 FirstFieldOffset = FOffset;
892 } else if (FOffset > LastFieldOffset) {
894 LastFieldOffset = FOffset;
898 const VarDecl *SrcRec;
899 const ASTRecordLayout &RecLayout;
900 FieldDecl *FirstField;
901 FieldDecl *LastField;
902 uint64_t FirstFieldOffset, LastFieldOffset;
903 unsigned LastAddedFieldIndex;
906 class ConstructorMemcpyizer : public FieldMemcpyizer {
909 /// Get source argument for copy constructor. Returns null if not a copy
911 static const VarDecl* getTrivialCopySource(const CXXConstructorDecl *CD,
912 FunctionArgList &Args) {
913 if (CD->isCopyOrMoveConstructor() && CD->isDefaulted())
914 return Args[Args.size() - 1];
918 // Returns true if a CXXCtorInitializer represents a member initialization
919 // that can be rolled into a memcpy.
920 bool isMemberInitMemcpyable(CXXCtorInitializer *MemberInit) const {
923 FieldDecl *Field = MemberInit->getMember();
924 assert(Field != 0 && "No field for member init.");
925 QualType FieldType = Field->getType();
926 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
928 // Bail out on non-POD, not-trivially-constructable members.
929 if (!(CE && CE->getConstructor()->isTrivial()) &&
930 !(FieldType.isTriviallyCopyableType(CGF.getContext()) ||
931 FieldType->isReferenceType()))
934 // Bail out on volatile fields.
935 if (!isMemcpyableField(Field))
938 // Otherwise we're good.
943 ConstructorMemcpyizer(CodeGenFunction &CGF, const CXXConstructorDecl *CD,
944 FunctionArgList &Args)
945 : FieldMemcpyizer(CGF, CD->getParent(), getTrivialCopySource(CD, Args)),
947 MemcpyableCtor(CD->isDefaulted() &&
948 CD->isCopyOrMoveConstructor() &&
949 CGF.getLangOpts().getGC() == LangOptions::NonGC),
952 void addMemberInitializer(CXXCtorInitializer *MemberInit) {
953 if (isMemberInitMemcpyable(MemberInit)) {
954 AggregatedInits.push_back(MemberInit);
955 addMemcpyableField(MemberInit->getMember());
957 emitAggregatedInits();
958 EmitMemberInitializer(CGF, ConstructorDecl->getParent(), MemberInit,
959 ConstructorDecl, Args);
963 void emitAggregatedInits() {
964 if (AggregatedInits.size() <= 1) {
965 // This memcpy is too small to be worthwhile. Fall back on default
967 if (!AggregatedInits.empty()) {
968 CopyingValueRepresentation CVR(CGF);
969 EmitMemberInitializer(CGF, ConstructorDecl->getParent(),
970 AggregatedInits[0], ConstructorDecl, Args);
978 AggregatedInits.clear();
981 void pushEHDestructors() {
982 llvm::Value *ThisPtr = CGF.LoadCXXThis();
983 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
984 LValue LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
986 for (unsigned i = 0; i < AggregatedInits.size(); ++i) {
987 QualType FieldType = AggregatedInits[i]->getMember()->getType();
988 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
989 if (CGF.needsEHCleanup(dtorKind))
990 CGF.pushEHDestroy(dtorKind, LHS.getAddress(), FieldType);
995 emitAggregatedInits();
999 const CXXConstructorDecl *ConstructorDecl;
1000 bool MemcpyableCtor;
1001 FunctionArgList &Args;
1002 SmallVector<CXXCtorInitializer*, 16> AggregatedInits;
1005 class AssignmentMemcpyizer : public FieldMemcpyizer {
1008 // Returns the memcpyable field copied by the given statement, if one
1009 // exists. Otherwise returns null.
1010 FieldDecl *getMemcpyableField(Stmt *S) {
1011 if (!AssignmentsMemcpyable)
1013 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(S)) {
1014 // Recognise trivial assignments.
1015 if (BO->getOpcode() != BO_Assign)
1017 MemberExpr *ME = dyn_cast<MemberExpr>(BO->getLHS());
1020 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1021 if (!Field || !isMemcpyableField(Field))
1023 Stmt *RHS = BO->getRHS();
1024 if (ImplicitCastExpr *EC = dyn_cast<ImplicitCastExpr>(RHS))
1025 RHS = EC->getSubExpr();
1028 MemberExpr *ME2 = dyn_cast<MemberExpr>(RHS);
1029 if (dyn_cast<FieldDecl>(ME2->getMemberDecl()) != Field)
1032 } else if (CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(S)) {
1033 CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MCE->getCalleeDecl());
1034 if (!(MD && (MD->isCopyAssignmentOperator() ||
1035 MD->isMoveAssignmentOperator()) &&
1038 MemberExpr *IOA = dyn_cast<MemberExpr>(MCE->getImplicitObjectArgument());
1041 FieldDecl *Field = dyn_cast<FieldDecl>(IOA->getMemberDecl());
1042 if (!Field || !isMemcpyableField(Field))
1044 MemberExpr *Arg0 = dyn_cast<MemberExpr>(MCE->getArg(0));
1045 if (!Arg0 || Field != dyn_cast<FieldDecl>(Arg0->getMemberDecl()))
1048 } else if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
1049 FunctionDecl *FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
1050 if (!FD || FD->getBuiltinID() != Builtin::BI__builtin_memcpy)
1052 Expr *DstPtr = CE->getArg(0);
1053 if (ImplicitCastExpr *DC = dyn_cast<ImplicitCastExpr>(DstPtr))
1054 DstPtr = DC->getSubExpr();
1055 UnaryOperator *DUO = dyn_cast<UnaryOperator>(DstPtr);
1056 if (!DUO || DUO->getOpcode() != UO_AddrOf)
1058 MemberExpr *ME = dyn_cast<MemberExpr>(DUO->getSubExpr());
1061 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1062 if (!Field || !isMemcpyableField(Field))
1064 Expr *SrcPtr = CE->getArg(1);
1065 if (ImplicitCastExpr *SC = dyn_cast<ImplicitCastExpr>(SrcPtr))
1066 SrcPtr = SC->getSubExpr();
1067 UnaryOperator *SUO = dyn_cast<UnaryOperator>(SrcPtr);
1068 if (!SUO || SUO->getOpcode() != UO_AddrOf)
1070 MemberExpr *ME2 = dyn_cast<MemberExpr>(SUO->getSubExpr());
1071 if (!ME2 || Field != dyn_cast<FieldDecl>(ME2->getMemberDecl()))
1079 bool AssignmentsMemcpyable;
1080 SmallVector<Stmt*, 16> AggregatedStmts;
1084 AssignmentMemcpyizer(CodeGenFunction &CGF, const CXXMethodDecl *AD,
1085 FunctionArgList &Args)
1086 : FieldMemcpyizer(CGF, AD->getParent(), Args[Args.size() - 1]),
1087 AssignmentsMemcpyable(CGF.getLangOpts().getGC() == LangOptions::NonGC) {
1088 assert(Args.size() == 2);
1091 void emitAssignment(Stmt *S) {
1092 FieldDecl *F = getMemcpyableField(S);
1094 addMemcpyableField(F);
1095 AggregatedStmts.push_back(S);
1097 emitAggregatedStmts();
1102 void emitAggregatedStmts() {
1103 if (AggregatedStmts.size() <= 1) {
1104 if (!AggregatedStmts.empty()) {
1105 CopyingValueRepresentation CVR(CGF);
1106 CGF.EmitStmt(AggregatedStmts[0]);
1112 AggregatedStmts.clear();
1116 emitAggregatedStmts();
1122 /// EmitCtorPrologue - This routine generates necessary code to initialize
1123 /// base classes and non-static data members belonging to this constructor.
1124 void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
1125 CXXCtorType CtorType,
1126 FunctionArgList &Args) {
1127 if (CD->isDelegatingConstructor())
1128 return EmitDelegatingCXXConstructorCall(CD, Args);
1130 const CXXRecordDecl *ClassDecl = CD->getParent();
1132 CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
1135 llvm::BasicBlock *BaseCtorContinueBB = 0;
1136 if (ClassDecl->getNumVBases() &&
1137 !CGM.getTarget().getCXXABI().hasConstructorVariants()) {
1138 // The ABIs that don't have constructor variants need to put a branch
1139 // before the virtual base initialization code.
1140 BaseCtorContinueBB =
1141 CGM.getCXXABI().EmitCtorCompleteObjectHandler(*this, ClassDecl);
1142 assert(BaseCtorContinueBB);
1145 // Virtual base initializers first.
1146 for (; B != E && (*B)->isBaseInitializer() && (*B)->isBaseVirtual(); B++) {
1147 EmitBaseInitializer(*this, ClassDecl, *B, CtorType);
1150 if (BaseCtorContinueBB) {
1151 // Complete object handler should continue to the remaining initializers.
1152 Builder.CreateBr(BaseCtorContinueBB);
1153 EmitBlock(BaseCtorContinueBB);
1156 // Then, non-virtual base initializers.
1157 for (; B != E && (*B)->isBaseInitializer(); B++) {
1158 assert(!(*B)->isBaseVirtual());
1159 EmitBaseInitializer(*this, ClassDecl, *B, CtorType);
1162 InitializeVTablePointers(ClassDecl);
1164 // And finally, initialize class members.
1165 FieldConstructionScope FCS(*this, CXXThisValue);
1166 ConstructorMemcpyizer CM(*this, CD, Args);
1167 for (; B != E; B++) {
1168 CXXCtorInitializer *Member = (*B);
1169 assert(!Member->isBaseInitializer());
1170 assert(Member->isAnyMemberInitializer() &&
1171 "Delegating initializer on non-delegating constructor");
1172 CM.addMemberInitializer(Member);
1178 FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field);
1181 HasTrivialDestructorBody(ASTContext &Context,
1182 const CXXRecordDecl *BaseClassDecl,
1183 const CXXRecordDecl *MostDerivedClassDecl)
1185 // If the destructor is trivial we don't have to check anything else.
1186 if (BaseClassDecl->hasTrivialDestructor())
1189 if (!BaseClassDecl->getDestructor()->hasTrivialBody())
1193 for (CXXRecordDecl::field_iterator I = BaseClassDecl->field_begin(),
1194 E = BaseClassDecl->field_end(); I != E; ++I) {
1195 const FieldDecl *Field = *I;
1197 if (!FieldHasTrivialDestructorBody(Context, Field))
1201 // Check non-virtual bases.
1202 for (CXXRecordDecl::base_class_const_iterator I =
1203 BaseClassDecl->bases_begin(), E = BaseClassDecl->bases_end();
1208 const CXXRecordDecl *NonVirtualBase =
1209 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
1210 if (!HasTrivialDestructorBody(Context, NonVirtualBase,
1211 MostDerivedClassDecl))
1215 if (BaseClassDecl == MostDerivedClassDecl) {
1216 // Check virtual bases.
1217 for (CXXRecordDecl::base_class_const_iterator I =
1218 BaseClassDecl->vbases_begin(), E = BaseClassDecl->vbases_end();
1220 const CXXRecordDecl *VirtualBase =
1221 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
1222 if (!HasTrivialDestructorBody(Context, VirtualBase,
1223 MostDerivedClassDecl))
1232 FieldHasTrivialDestructorBody(ASTContext &Context,
1233 const FieldDecl *Field)
1235 QualType FieldBaseElementType = Context.getBaseElementType(Field->getType());
1237 const RecordType *RT = FieldBaseElementType->getAs<RecordType>();
1241 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
1242 return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl);
1245 /// CanSkipVTablePointerInitialization - Check whether we need to initialize
1246 /// any vtable pointers before calling this destructor.
1247 static bool CanSkipVTablePointerInitialization(ASTContext &Context,
1248 const CXXDestructorDecl *Dtor) {
1249 if (!Dtor->hasTrivialBody())
1252 // Check the fields.
1253 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1254 for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
1255 E = ClassDecl->field_end(); I != E; ++I) {
1256 const FieldDecl *Field = *I;
1258 if (!FieldHasTrivialDestructorBody(Context, Field))
1265 /// EmitDestructorBody - Emits the body of the current destructor.
1266 void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
1267 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
1268 CXXDtorType DtorType = CurGD.getDtorType();
1270 // The call to operator delete in a deleting destructor happens
1271 // outside of the function-try-block, which means it's always
1272 // possible to delegate the destructor body to the complete
1273 // destructor. Do so.
1274 if (DtorType == Dtor_Deleting) {
1275 EnterDtorCleanups(Dtor, Dtor_Deleting);
1276 EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
1277 /*Delegating=*/false, LoadCXXThis());
1282 Stmt *Body = Dtor->getBody();
1284 // If the body is a function-try-block, enter the try before
1286 bool isTryBody = (Body && isa<CXXTryStmt>(Body));
1288 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1290 // Enter the epilogue cleanups.
1291 RunCleanupsScope DtorEpilogue(*this);
1293 // If this is the complete variant, just invoke the base variant;
1294 // the epilogue will destruct the virtual bases. But we can't do
1295 // this optimization if the body is a function-try-block, because
1296 // we'd introduce *two* handler blocks. In the Microsoft ABI, we
1297 // always delegate because we might not have a definition in this TU.
1299 case Dtor_Deleting: llvm_unreachable("already handled deleting case");
1302 assert((Body || getTarget().getCXXABI().isMicrosoft()) &&
1303 "can't emit a dtor without a body for non-Microsoft ABIs");
1305 // Enter the cleanup scopes for virtual bases.
1306 EnterDtorCleanups(Dtor, Dtor_Complete);
1309 EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
1310 /*Delegating=*/false, LoadCXXThis());
1313 // Fallthrough: act like we're in the base variant.
1318 // Enter the cleanup scopes for fields and non-virtual bases.
1319 EnterDtorCleanups(Dtor, Dtor_Base);
1321 // Initialize the vtable pointers before entering the body.
1322 if (!CanSkipVTablePointerInitialization(getContext(), Dtor))
1323 InitializeVTablePointers(Dtor->getParent());
1326 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
1330 assert(Dtor->isImplicit() && "bodyless dtor not implicit");
1331 // nothing to do besides what's in the epilogue
1333 // -fapple-kext must inline any call to this dtor into
1334 // the caller's body.
1335 if (getLangOpts().AppleKext)
1336 CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
1340 // Jump out through the epilogue cleanups.
1341 DtorEpilogue.ForceCleanup();
1343 // Exit the try if applicable.
1345 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1348 void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) {
1349 const CXXMethodDecl *AssignOp = cast<CXXMethodDecl>(CurGD.getDecl());
1350 const Stmt *RootS = AssignOp->getBody();
1351 assert(isa<CompoundStmt>(RootS) &&
1352 "Body of an implicit assignment operator should be compound stmt.");
1353 const CompoundStmt *RootCS = cast<CompoundStmt>(RootS);
1355 LexicalScope Scope(*this, RootCS->getSourceRange());
1357 AssignmentMemcpyizer AM(*this, AssignOp, Args);
1358 for (CompoundStmt::const_body_iterator I = RootCS->body_begin(),
1359 E = RootCS->body_end();
1361 AM.emitAssignment(*I);
1367 /// Call the operator delete associated with the current destructor.
1368 struct CallDtorDelete : EHScopeStack::Cleanup {
1371 void Emit(CodeGenFunction &CGF, Flags flags) {
1372 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1373 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1374 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
1375 CGF.getContext().getTagDeclType(ClassDecl));
1379 struct CallDtorDeleteConditional : EHScopeStack::Cleanup {
1380 llvm::Value *ShouldDeleteCondition;
1382 CallDtorDeleteConditional(llvm::Value *ShouldDeleteCondition)
1383 : ShouldDeleteCondition(ShouldDeleteCondition) {
1384 assert(ShouldDeleteCondition != NULL);
1387 void Emit(CodeGenFunction &CGF, Flags flags) {
1388 llvm::BasicBlock *callDeleteBB = CGF.createBasicBlock("dtor.call_delete");
1389 llvm::BasicBlock *continueBB = CGF.createBasicBlock("dtor.continue");
1390 llvm::Value *ShouldCallDelete
1391 = CGF.Builder.CreateIsNull(ShouldDeleteCondition);
1392 CGF.Builder.CreateCondBr(ShouldCallDelete, continueBB, callDeleteBB);
1394 CGF.EmitBlock(callDeleteBB);
1395 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1396 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1397 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
1398 CGF.getContext().getTagDeclType(ClassDecl));
1399 CGF.Builder.CreateBr(continueBB);
1401 CGF.EmitBlock(continueBB);
1405 class DestroyField : public EHScopeStack::Cleanup {
1406 const FieldDecl *field;
1407 CodeGenFunction::Destroyer *destroyer;
1408 bool useEHCleanupForArray;
1411 DestroyField(const FieldDecl *field, CodeGenFunction::Destroyer *destroyer,
1412 bool useEHCleanupForArray)
1413 : field(field), destroyer(destroyer),
1414 useEHCleanupForArray(useEHCleanupForArray) {}
1416 void Emit(CodeGenFunction &CGF, Flags flags) {
1417 // Find the address of the field.
1418 llvm::Value *thisValue = CGF.LoadCXXThis();
1419 QualType RecordTy = CGF.getContext().getTagDeclType(field->getParent());
1420 LValue ThisLV = CGF.MakeAddrLValue(thisValue, RecordTy);
1421 LValue LV = CGF.EmitLValueForField(ThisLV, field);
1422 assert(LV.isSimple());
1424 CGF.emitDestroy(LV.getAddress(), field->getType(), destroyer,
1425 flags.isForNormalCleanup() && useEHCleanupForArray);
1430 /// EmitDtorEpilogue - Emit all code that comes at the end of class's
1431 /// destructor. This is to call destructors on members and base classes
1432 /// in reverse order of their construction.
1433 void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD,
1434 CXXDtorType DtorType) {
1435 assert(!DD->isTrivial() &&
1436 "Should not emit dtor epilogue for trivial dtor!");
1438 // The deleting-destructor phase just needs to call the appropriate
1439 // operator delete that Sema picked up.
1440 if (DtorType == Dtor_Deleting) {
1441 assert(DD->getOperatorDelete() &&
1442 "operator delete missing - EmitDtorEpilogue");
1443 if (CXXStructorImplicitParamValue) {
1444 // If there is an implicit param to the deleting dtor, it's a boolean
1445 // telling whether we should call delete at the end of the dtor.
1446 EHStack.pushCleanup<CallDtorDeleteConditional>(
1447 NormalAndEHCleanup, CXXStructorImplicitParamValue);
1449 EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
1454 const CXXRecordDecl *ClassDecl = DD->getParent();
1456 // Unions have no bases and do not call field destructors.
1457 if (ClassDecl->isUnion())
1460 // The complete-destructor phase just destructs all the virtual bases.
1461 if (DtorType == Dtor_Complete) {
1463 // We push them in the forward order so that they'll be popped in
1464 // the reverse order.
1465 for (CXXRecordDecl::base_class_const_iterator I =
1466 ClassDecl->vbases_begin(), E = ClassDecl->vbases_end();
1468 const CXXBaseSpecifier &Base = *I;
1469 CXXRecordDecl *BaseClassDecl
1470 = cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
1472 // Ignore trivial destructors.
1473 if (BaseClassDecl->hasTrivialDestructor())
1476 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1478 /*BaseIsVirtual*/ true);
1484 assert(DtorType == Dtor_Base);
1486 // Destroy non-virtual bases.
1487 for (CXXRecordDecl::base_class_const_iterator I =
1488 ClassDecl->bases_begin(), E = ClassDecl->bases_end(); I != E; ++I) {
1489 const CXXBaseSpecifier &Base = *I;
1491 // Ignore virtual bases.
1492 if (Base.isVirtual())
1495 CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
1497 // Ignore trivial destructors.
1498 if (BaseClassDecl->hasTrivialDestructor())
1501 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1503 /*BaseIsVirtual*/ false);
1506 // Destroy direct fields.
1507 SmallVector<const FieldDecl *, 16> FieldDecls;
1508 for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
1509 E = ClassDecl->field_end(); I != E; ++I) {
1510 const FieldDecl *field = *I;
1511 QualType type = field->getType();
1512 QualType::DestructionKind dtorKind = type.isDestructedType();
1513 if (!dtorKind) continue;
1515 // Anonymous union members do not have their destructors called.
1516 const RecordType *RT = type->getAsUnionType();
1517 if (RT && RT->getDecl()->isAnonymousStructOrUnion()) continue;
1519 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1520 EHStack.pushCleanup<DestroyField>(cleanupKind, field,
1521 getDestroyer(dtorKind),
1522 cleanupKind & EHCleanup);
1526 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1527 /// constructor for each of several members of an array.
1529 /// \param ctor the constructor to call for each element
1530 /// \param arrayType the type of the array to initialize
1531 /// \param arrayBegin an arrayType*
1532 /// \param zeroInitialize true if each element should be
1533 /// zero-initialized before it is constructed
1535 CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1536 const ConstantArrayType *arrayType,
1537 llvm::Value *arrayBegin,
1538 CallExpr::const_arg_iterator argBegin,
1539 CallExpr::const_arg_iterator argEnd,
1540 bool zeroInitialize) {
1541 QualType elementType;
1542 llvm::Value *numElements =
1543 emitArrayLength(arrayType, elementType, arrayBegin);
1545 EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin,
1546 argBegin, argEnd, zeroInitialize);
1549 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1550 /// constructor for each of several members of an array.
1552 /// \param ctor the constructor to call for each element
1553 /// \param numElements the number of elements in the array;
1555 /// \param arrayBegin a T*, where T is the type constructed by ctor
1556 /// \param zeroInitialize true if each element should be
1557 /// zero-initialized before it is constructed
1559 CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1560 llvm::Value *numElements,
1561 llvm::Value *arrayBegin,
1562 CallExpr::const_arg_iterator argBegin,
1563 CallExpr::const_arg_iterator argEnd,
1564 bool zeroInitialize) {
1566 // It's legal for numElements to be zero. This can happen both
1567 // dynamically, because x can be zero in 'new A[x]', and statically,
1568 // because of GCC extensions that permit zero-length arrays. There
1569 // are probably legitimate places where we could assume that this
1570 // doesn't happen, but it's not clear that it's worth it.
1571 llvm::BranchInst *zeroCheckBranch = 0;
1573 // Optimize for a constant count.
1574 llvm::ConstantInt *constantCount
1575 = dyn_cast<llvm::ConstantInt>(numElements);
1576 if (constantCount) {
1577 // Just skip out if the constant count is zero.
1578 if (constantCount->isZero()) return;
1580 // Otherwise, emit the check.
1582 llvm::BasicBlock *loopBB = createBasicBlock("new.ctorloop");
1583 llvm::Value *iszero = Builder.CreateIsNull(numElements, "isempty");
1584 zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB);
1588 // Find the end of the array.
1589 llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(arrayBegin, numElements,
1592 // Enter the loop, setting up a phi for the current location to initialize.
1593 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1594 llvm::BasicBlock *loopBB = createBasicBlock("arrayctor.loop");
1596 llvm::PHINode *cur = Builder.CreatePHI(arrayBegin->getType(), 2,
1598 cur->addIncoming(arrayBegin, entryBB);
1600 // Inside the loop body, emit the constructor call on the array element.
1602 QualType type = getContext().getTypeDeclType(ctor->getParent());
1604 // Zero initialize the storage, if requested.
1606 EmitNullInitialization(cur, type);
1608 // C++ [class.temporary]p4:
1609 // There are two contexts in which temporaries are destroyed at a different
1610 // point than the end of the full-expression. The first context is when a
1611 // default constructor is called to initialize an element of an array.
1612 // If the constructor has one or more default arguments, the destruction of
1613 // every temporary created in a default argument expression is sequenced
1614 // before the construction of the next array element, if any.
1617 RunCleanupsScope Scope(*this);
1619 // Evaluate the constructor and its arguments in a regular
1620 // partial-destroy cleanup.
1621 if (getLangOpts().Exceptions &&
1622 !ctor->getParent()->hasTrivialDestructor()) {
1623 Destroyer *destroyer = destroyCXXObject;
1624 pushRegularPartialArrayCleanup(arrayBegin, cur, type, *destroyer);
1627 EmitCXXConstructorCall(ctor, Ctor_Complete, /*ForVirtualBase=*/ false,
1628 /*Delegating=*/false, cur, argBegin, argEnd);
1631 // Go to the next element.
1633 Builder.CreateInBoundsGEP(cur, llvm::ConstantInt::get(SizeTy, 1),
1635 cur->addIncoming(next, Builder.GetInsertBlock());
1637 // Check whether that's the end of the loop.
1638 llvm::Value *done = Builder.CreateICmpEQ(next, arrayEnd, "arrayctor.done");
1639 llvm::BasicBlock *contBB = createBasicBlock("arrayctor.cont");
1640 Builder.CreateCondBr(done, contBB, loopBB);
1642 // Patch the earlier check to skip over the loop.
1643 if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB);
1648 void CodeGenFunction::destroyCXXObject(CodeGenFunction &CGF,
1651 const RecordType *rtype = type->castAs<RecordType>();
1652 const CXXRecordDecl *record = cast<CXXRecordDecl>(rtype->getDecl());
1653 const CXXDestructorDecl *dtor = record->getDestructor();
1654 assert(!dtor->isTrivial());
1655 CGF.EmitCXXDestructorCall(dtor, Dtor_Complete, /*for vbase*/ false,
1656 /*Delegating=*/false, addr);
1660 CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
1661 CXXCtorType Type, bool ForVirtualBase,
1664 CallExpr::const_arg_iterator ArgBeg,
1665 CallExpr::const_arg_iterator ArgEnd) {
1666 // If this is a trivial constructor, just emit what's needed.
1667 if (D->isTrivial()) {
1668 if (ArgBeg == ArgEnd) {
1669 // Trivial default constructor, no codegen required.
1670 assert(D->isDefaultConstructor() &&
1671 "trivial 0-arg ctor not a default ctor");
1675 assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
1676 assert(D->isCopyOrMoveConstructor() &&
1677 "trivial 1-arg ctor not a copy/move ctor");
1679 const Expr *E = (*ArgBeg);
1680 QualType Ty = E->getType();
1681 llvm::Value *Src = EmitLValue(E).getAddress();
1682 EmitAggregateCopy(This, Src, Ty);
1686 // Non-trivial constructors are handled in an ABI-specific manner.
1687 CGM.getCXXABI().EmitConstructorCall(*this, D, Type, ForVirtualBase,
1688 Delegating, This, ArgBeg, ArgEnd);
1692 CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
1693 llvm::Value *This, llvm::Value *Src,
1694 CallExpr::const_arg_iterator ArgBeg,
1695 CallExpr::const_arg_iterator ArgEnd) {
1696 if (D->isTrivial()) {
1697 assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
1698 assert(D->isCopyOrMoveConstructor() &&
1699 "trivial 1-arg ctor not a copy/move ctor");
1700 EmitAggregateCopy(This, Src, (*ArgBeg)->getType());
1703 llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, clang::Ctor_Complete);
1704 assert(D->isInstance() &&
1705 "Trying to emit a member call expr on a static method!");
1707 const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
1711 // Push the this ptr.
1712 Args.add(RValue::get(This), D->getThisType(getContext()));
1715 // Push the src ptr.
1716 QualType QT = *(FPT->arg_type_begin());
1717 llvm::Type *t = CGM.getTypes().ConvertType(QT);
1718 Src = Builder.CreateBitCast(Src, t);
1719 Args.add(RValue::get(Src), QT);
1721 // Skip over first argument (Src).
1723 CallExpr::const_arg_iterator Arg = ArgBeg;
1724 for (FunctionProtoType::arg_type_iterator I = FPT->arg_type_begin()+1,
1725 E = FPT->arg_type_end(); I != E; ++I, ++Arg) {
1726 assert(Arg != ArgEnd && "Running over edge of argument list!");
1727 EmitCallArg(Args, *Arg, *I);
1729 // Either we've emitted all the call args, or we have a call to a
1730 // variadic function.
1731 assert((Arg == ArgEnd || FPT->isVariadic()) &&
1732 "Extra arguments in non-variadic function!");
1733 // If we still have any arguments, emit them using the type of the argument.
1734 for (; Arg != ArgEnd; ++Arg) {
1735 QualType ArgType = Arg->getType();
1736 EmitCallArg(Args, *Arg, ArgType);
1739 EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, RequiredArgs::All),
1740 Callee, ReturnValueSlot(), Args, D);
1744 CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
1745 CXXCtorType CtorType,
1746 const FunctionArgList &Args,
1747 SourceLocation Loc) {
1748 CallArgList DelegateArgs;
1750 FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
1751 assert(I != E && "no parameters to constructor");
1754 DelegateArgs.add(RValue::get(LoadCXXThis()), (*I)->getType());
1758 if (llvm::Value *VTT = GetVTTParameter(GlobalDecl(Ctor, CtorType),
1759 /*ForVirtualBase=*/false,
1760 /*Delegating=*/true)) {
1761 QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy);
1762 DelegateArgs.add(RValue::get(VTT), VoidPP);
1764 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
1765 assert(I != E && "cannot skip vtt parameter, already done with args");
1766 assert((*I)->getType() == VoidPP && "skipping parameter not of vtt type");
1771 // Explicit arguments.
1772 for (; I != E; ++I) {
1773 const VarDecl *param = *I;
1774 // FIXME: per-argument source location
1775 EmitDelegateCallArg(DelegateArgs, param, Loc);
1778 llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(Ctor, CtorType);
1779 EmitCall(CGM.getTypes().arrangeCXXConstructorDeclaration(Ctor, CtorType),
1780 Callee, ReturnValueSlot(), DelegateArgs, Ctor);
1784 struct CallDelegatingCtorDtor : EHScopeStack::Cleanup {
1785 const CXXDestructorDecl *Dtor;
1789 CallDelegatingCtorDtor(const CXXDestructorDecl *D, llvm::Value *Addr,
1791 : Dtor(D), Addr(Addr), Type(Type) {}
1793 void Emit(CodeGenFunction &CGF, Flags flags) {
1794 CGF.EmitCXXDestructorCall(Dtor, Type, /*ForVirtualBase=*/false,
1795 /*Delegating=*/true, Addr);
1801 CodeGenFunction::EmitDelegatingCXXConstructorCall(const CXXConstructorDecl *Ctor,
1802 const FunctionArgList &Args) {
1803 assert(Ctor->isDelegatingConstructor());
1805 llvm::Value *ThisPtr = LoadCXXThis();
1807 QualType Ty = getContext().getTagDeclType(Ctor->getParent());
1808 CharUnits Alignment = getContext().getTypeAlignInChars(Ty);
1809 AggValueSlot AggSlot =
1810 AggValueSlot::forAddr(ThisPtr, Alignment, Qualifiers(),
1811 AggValueSlot::IsDestructed,
1812 AggValueSlot::DoesNotNeedGCBarriers,
1813 AggValueSlot::IsNotAliased);
1815 EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot);
1817 const CXXRecordDecl *ClassDecl = Ctor->getParent();
1818 if (CGM.getLangOpts().Exceptions && !ClassDecl->hasTrivialDestructor()) {
1820 CurGD.getCtorType() == Ctor_Complete ? Dtor_Complete : Dtor_Base;
1822 EHStack.pushCleanup<CallDelegatingCtorDtor>(EHCleanup,
1823 ClassDecl->getDestructor(),
1828 void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
1830 bool ForVirtualBase,
1832 llvm::Value *This) {
1833 GlobalDecl GD(DD, Type);
1834 llvm::Value *VTT = GetVTTParameter(GD, ForVirtualBase, Delegating);
1835 llvm::Value *Callee = 0;
1836 if (getLangOpts().AppleKext)
1837 Callee = BuildAppleKextVirtualDestructorCall(DD, Type,
1841 Callee = CGM.GetAddrOfCXXDestructor(DD, Type);
1843 if (DD->isVirtual())
1844 This = CGM.getCXXABI().adjustThisArgumentForVirtualCall(*this, GD, This);
1846 // FIXME: Provide a source location here.
1847 EmitCXXMemberCall(DD, SourceLocation(), Callee, ReturnValueSlot(), This,
1848 VTT, getContext().getPointerType(getContext().VoidPtrTy),
1853 struct CallLocalDtor : EHScopeStack::Cleanup {
1854 const CXXDestructorDecl *Dtor;
1857 CallLocalDtor(const CXXDestructorDecl *D, llvm::Value *Addr)
1858 : Dtor(D), Addr(Addr) {}
1860 void Emit(CodeGenFunction &CGF, Flags flags) {
1861 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1862 /*ForVirtualBase=*/false,
1863 /*Delegating=*/false, Addr);
1868 void CodeGenFunction::PushDestructorCleanup(const CXXDestructorDecl *D,
1869 llvm::Value *Addr) {
1870 EHStack.pushCleanup<CallLocalDtor>(NormalAndEHCleanup, D, Addr);
1873 void CodeGenFunction::PushDestructorCleanup(QualType T, llvm::Value *Addr) {
1874 CXXRecordDecl *ClassDecl = T->getAsCXXRecordDecl();
1875 if (!ClassDecl) return;
1876 if (ClassDecl->hasTrivialDestructor()) return;
1878 const CXXDestructorDecl *D = ClassDecl->getDestructor();
1879 assert(D && D->isUsed() && "destructor not marked as used!");
1880 PushDestructorCleanup(D, Addr);
1884 CodeGenFunction::InitializeVTablePointer(BaseSubobject Base,
1885 const CXXRecordDecl *NearestVBase,
1886 CharUnits OffsetFromNearestVBase,
1887 const CXXRecordDecl *VTableClass) {
1888 // Compute the address point.
1889 bool NeedsVirtualOffset;
1890 llvm::Value *VTableAddressPoint =
1891 CGM.getCXXABI().getVTableAddressPointInStructor(
1892 *this, VTableClass, Base, NearestVBase, NeedsVirtualOffset);
1893 if (!VTableAddressPoint)
1896 // Compute where to store the address point.
1897 llvm::Value *VirtualOffset = 0;
1898 CharUnits NonVirtualOffset = CharUnits::Zero();
1900 if (NeedsVirtualOffset) {
1901 // We need to use the virtual base offset offset because the virtual base
1902 // might have a different offset in the most derived class.
1903 VirtualOffset = CGM.getCXXABI().GetVirtualBaseClassOffset(*this,
1907 NonVirtualOffset = OffsetFromNearestVBase;
1909 // We can just use the base offset in the complete class.
1910 NonVirtualOffset = Base.getBaseOffset();
1913 // Apply the offsets.
1914 llvm::Value *VTableField = LoadCXXThis();
1916 if (!NonVirtualOffset.isZero() || VirtualOffset)
1917 VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField,
1921 // Finally, store the address point.
1922 llvm::Type *AddressPointPtrTy =
1923 VTableAddressPoint->getType()->getPointerTo();
1924 VTableField = Builder.CreateBitCast(VTableField, AddressPointPtrTy);
1925 llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
1926 CGM.DecorateInstruction(Store, CGM.getTBAAInfoForVTablePtr());
1930 CodeGenFunction::InitializeVTablePointers(BaseSubobject Base,
1931 const CXXRecordDecl *NearestVBase,
1932 CharUnits OffsetFromNearestVBase,
1933 bool BaseIsNonVirtualPrimaryBase,
1934 const CXXRecordDecl *VTableClass,
1935 VisitedVirtualBasesSetTy& VBases) {
1936 // If this base is a non-virtual primary base the address point has already
1938 if (!BaseIsNonVirtualPrimaryBase) {
1939 // Initialize the vtable pointer for this base.
1940 InitializeVTablePointer(Base, NearestVBase, OffsetFromNearestVBase,
1944 const CXXRecordDecl *RD = Base.getBase();
1947 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
1948 E = RD->bases_end(); I != E; ++I) {
1949 CXXRecordDecl *BaseDecl
1950 = cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
1952 // Ignore classes without a vtable.
1953 if (!BaseDecl->isDynamicClass())
1956 CharUnits BaseOffset;
1957 CharUnits BaseOffsetFromNearestVBase;
1958 bool BaseDeclIsNonVirtualPrimaryBase;
1960 if (I->isVirtual()) {
1961 // Check if we've visited this virtual base before.
1962 if (!VBases.insert(BaseDecl))
1965 const ASTRecordLayout &Layout =
1966 getContext().getASTRecordLayout(VTableClass);
1968 BaseOffset = Layout.getVBaseClassOffset(BaseDecl);
1969 BaseOffsetFromNearestVBase = CharUnits::Zero();
1970 BaseDeclIsNonVirtualPrimaryBase = false;
1972 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1974 BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl);
1975 BaseOffsetFromNearestVBase =
1976 OffsetFromNearestVBase + Layout.getBaseClassOffset(BaseDecl);
1977 BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl;
1980 InitializeVTablePointers(BaseSubobject(BaseDecl, BaseOffset),
1981 I->isVirtual() ? BaseDecl : NearestVBase,
1982 BaseOffsetFromNearestVBase,
1983 BaseDeclIsNonVirtualPrimaryBase,
1984 VTableClass, VBases);
1988 void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
1989 // Ignore classes without a vtable.
1990 if (!RD->isDynamicClass())
1993 // Initialize the vtable pointers for this class and all of its bases.
1994 VisitedVirtualBasesSetTy VBases;
1995 InitializeVTablePointers(BaseSubobject(RD, CharUnits::Zero()),
1997 /*OffsetFromNearestVBase=*/CharUnits::Zero(),
1998 /*BaseIsNonVirtualPrimaryBase=*/false, RD, VBases);
2000 if (RD->getNumVBases())
2001 CGM.getCXXABI().initializeHiddenVirtualInheritanceMembers(*this, RD);
2004 llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
2006 llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo());
2007 llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable");
2008 CGM.DecorateInstruction(VTable, CGM.getTBAAInfoForVTablePtr());
2013 // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do
2014 // quite what we want.
2015 static const Expr *skipNoOpCastsAndParens(const Expr *E) {
2017 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
2018 E = PE->getSubExpr();
2022 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
2023 if (CE->getCastKind() == CK_NoOp) {
2024 E = CE->getSubExpr();
2028 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
2029 if (UO->getOpcode() == UO_Extension) {
2030 E = UO->getSubExpr();
2039 CodeGenFunction::CanDevirtualizeMemberFunctionCall(const Expr *Base,
2040 const CXXMethodDecl *MD) {
2041 // When building with -fapple-kext, all calls must go through the vtable since
2042 // the kernel linker can do runtime patching of vtables.
2043 if (getLangOpts().AppleKext)
2046 // If the most derived class is marked final, we know that no subclass can
2047 // override this member function and so we can devirtualize it. For example:
2049 // struct A { virtual void f(); }
2050 // struct B final : A { };
2056 const CXXRecordDecl *MostDerivedClassDecl = Base->getBestDynamicClassType();
2057 if (MostDerivedClassDecl->hasAttr<FinalAttr>())
2060 // If the member function is marked 'final', we know that it can't be
2061 // overridden and can therefore devirtualize it.
2062 if (MD->hasAttr<FinalAttr>())
2065 // Similarly, if the class itself is marked 'final' it can't be overridden
2066 // and we can therefore devirtualize the member function call.
2067 if (MD->getParent()->hasAttr<FinalAttr>())
2070 Base = skipNoOpCastsAndParens(Base);
2071 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
2072 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
2073 // This is a record decl. We know the type and can devirtualize it.
2074 return VD->getType()->isRecordType();
2080 // We can devirtualize calls on an object accessed by a class member access
2081 // expression, since by C++11 [basic.life]p6 we know that it can't refer to
2082 // a derived class object constructed in the same location.
2083 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Base))
2084 if (const ValueDecl *VD = dyn_cast<ValueDecl>(ME->getMemberDecl()))
2085 return VD->getType()->isRecordType();
2087 // We can always devirtualize calls on temporary object expressions.
2088 if (isa<CXXConstructExpr>(Base))
2091 // And calls on bound temporaries.
2092 if (isa<CXXBindTemporaryExpr>(Base))
2095 // Check if this is a call expr that returns a record type.
2096 if (const CallExpr *CE = dyn_cast<CallExpr>(Base))
2097 return CE->getCallReturnType()->isRecordType();
2099 // We can't devirtualize the call.
2104 CodeGenFunction::EmitCXXOperatorMemberCallee(const CXXOperatorCallExpr *E,
2105 const CXXMethodDecl *MD,
2106 llvm::Value *This) {
2107 llvm::FunctionType *fnType =
2108 CGM.getTypes().GetFunctionType(
2109 CGM.getTypes().arrangeCXXMethodDeclaration(MD));
2111 if (MD->isVirtual() && !CanDevirtualizeMemberFunctionCall(E->getArg(0), MD))
2112 return CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, fnType);
2114 return CGM.GetAddrOfFunction(MD, fnType);
2117 void CodeGenFunction::EmitForwardingCallToLambda(
2118 const CXXMethodDecl *callOperator,
2119 CallArgList &callArgs) {
2120 // Get the address of the call operator.
2121 const CGFunctionInfo &calleeFnInfo =
2122 CGM.getTypes().arrangeCXXMethodDeclaration(callOperator);
2123 llvm::Value *callee =
2124 CGM.GetAddrOfFunction(GlobalDecl(callOperator),
2125 CGM.getTypes().GetFunctionType(calleeFnInfo));
2127 // Prepare the return slot.
2128 const FunctionProtoType *FPT =
2129 callOperator->getType()->castAs<FunctionProtoType>();
2130 QualType resultType = FPT->getResultType();
2131 ReturnValueSlot returnSlot;
2132 if (!resultType->isVoidType() &&
2133 calleeFnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
2134 !hasScalarEvaluationKind(calleeFnInfo.getReturnType()))
2135 returnSlot = ReturnValueSlot(ReturnValue, resultType.isVolatileQualified());
2137 // We don't need to separately arrange the call arguments because
2138 // the call can't be variadic anyway --- it's impossible to forward
2139 // variadic arguments.
2141 // Now emit our call.
2142 RValue RV = EmitCall(calleeFnInfo, callee, returnSlot,
2143 callArgs, callOperator);
2145 // If necessary, copy the returned value into the slot.
2146 if (!resultType->isVoidType() && returnSlot.isNull())
2147 EmitReturnOfRValue(RV, resultType);
2149 EmitBranchThroughCleanup(ReturnBlock);
2152 void CodeGenFunction::EmitLambdaBlockInvokeBody() {
2153 const BlockDecl *BD = BlockInfo->getBlockDecl();
2154 const VarDecl *variable = BD->capture_begin()->getVariable();
2155 const CXXRecordDecl *Lambda = variable->getType()->getAsCXXRecordDecl();
2157 // Start building arguments for forwarding call
2158 CallArgList CallArgs;
2160 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2161 llvm::Value *ThisPtr = GetAddrOfBlockDecl(variable, false);
2162 CallArgs.add(RValue::get(ThisPtr), ThisType);
2164 // Add the rest of the parameters.
2165 for (BlockDecl::param_const_iterator I = BD->param_begin(),
2166 E = BD->param_end(); I != E; ++I) {
2167 ParmVarDecl *param = *I;
2168 EmitDelegateCallArg(CallArgs, param, param->getLocStart());
2170 assert(!Lambda->isGenericLambda() &&
2171 "generic lambda interconversion to block not implemented");
2172 EmitForwardingCallToLambda(Lambda->getLambdaCallOperator(), CallArgs);
2175 void CodeGenFunction::EmitLambdaToBlockPointerBody(FunctionArgList &Args) {
2176 if (cast<CXXMethodDecl>(CurCodeDecl)->isVariadic()) {
2177 // FIXME: Making this work correctly is nasty because it requires either
2178 // cloning the body of the call operator or making the call operator forward.
2179 CGM.ErrorUnsupported(CurCodeDecl, "lambda conversion to variadic function");
2183 EmitFunctionBody(Args, cast<FunctionDecl>(CurGD.getDecl())->getBody());
2186 void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) {
2187 const CXXRecordDecl *Lambda = MD->getParent();
2189 // Start building arguments for forwarding call
2190 CallArgList CallArgs;
2192 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2193 llvm::Value *ThisPtr = llvm::UndefValue::get(getTypes().ConvertType(ThisType));
2194 CallArgs.add(RValue::get(ThisPtr), ThisType);
2196 // Add the rest of the parameters.
2197 for (FunctionDecl::param_const_iterator I = MD->param_begin(),
2198 E = MD->param_end(); I != E; ++I) {
2199 ParmVarDecl *param = *I;
2200 EmitDelegateCallArg(CallArgs, param, param->getLocStart());
2202 const CXXMethodDecl *CallOp = Lambda->getLambdaCallOperator();
2203 // For a generic lambda, find the corresponding call operator specialization
2204 // to which the call to the static-invoker shall be forwarded.
2205 if (Lambda->isGenericLambda()) {
2206 assert(MD->isFunctionTemplateSpecialization());
2207 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
2208 FunctionTemplateDecl *CallOpTemplate = CallOp->getDescribedFunctionTemplate();
2209 void *InsertPos = 0;
2210 FunctionDecl *CorrespondingCallOpSpecialization =
2211 CallOpTemplate->findSpecialization(TAL->data(), TAL->size(), InsertPos);
2212 assert(CorrespondingCallOpSpecialization);
2213 CallOp = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
2215 EmitForwardingCallToLambda(CallOp, CallArgs);
2218 void CodeGenFunction::EmitLambdaStaticInvokeFunction(const CXXMethodDecl *MD) {
2219 if (MD->isVariadic()) {
2220 // FIXME: Making this work correctly is nasty because it requires either
2221 // cloning the body of the call operator or making the call operator forward.
2222 CGM.ErrorUnsupported(MD, "lambda conversion to variadic function");
2226 EmitLambdaDelegatingInvokeBody(MD);