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 const 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 const 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 const 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 const 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 const 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 const 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, bool IsForEH) {
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 = AggValueSlot::forAddr(V, false, /*Lifetime*/ true);
403 CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
405 if (CGF.CGM.getLangOptions().Exceptions &&
406 !BaseClassDecl->hasTrivialDestructor())
407 CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
411 static void EmitAggMemberInitializer(CodeGenFunction &CGF,
413 llvm::Value *ArrayIndexVar,
414 CXXCtorInitializer *MemberInit,
417 if (Index == MemberInit->getNumArrayIndices()) {
418 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
420 llvm::Value *Dest = LHS.getAddress();
422 // If we have an array index variable, load it and use it as an offset.
423 // Then, increment the value.
424 llvm::Value *ArrayIndex = CGF.Builder.CreateLoad(ArrayIndexVar);
425 Dest = CGF.Builder.CreateInBoundsGEP(Dest, ArrayIndex, "destaddress");
426 llvm::Value *Next = llvm::ConstantInt::get(ArrayIndex->getType(), 1);
427 Next = CGF.Builder.CreateAdd(ArrayIndex, Next, "inc");
428 CGF.Builder.CreateStore(Next, ArrayIndexVar);
431 AggValueSlot Slot = AggValueSlot::forAddr(Dest, LHS.isVolatileQualified(),
434 CGF.EmitAggExpr(MemberInit->getInit(), Slot);
439 const ConstantArrayType *Array = CGF.getContext().getAsConstantArrayType(T);
440 assert(Array && "Array initialization without the array type?");
441 llvm::Value *IndexVar
442 = CGF.GetAddrOfLocalVar(MemberInit->getArrayIndex(Index));
443 assert(IndexVar && "Array index variable not loaded");
445 // Initialize this index variable to zero.
447 = llvm::Constant::getNullValue(
448 CGF.ConvertType(CGF.getContext().getSizeType()));
449 CGF.Builder.CreateStore(Zero, IndexVar);
451 // Start the loop with a block that tests the condition.
452 llvm::BasicBlock *CondBlock = CGF.createBasicBlock("for.cond");
453 llvm::BasicBlock *AfterFor = CGF.createBasicBlock("for.end");
455 CGF.EmitBlock(CondBlock);
457 llvm::BasicBlock *ForBody = CGF.createBasicBlock("for.body");
458 // Generate: if (loop-index < number-of-elements) fall to the loop body,
459 // otherwise, go to the block after the for-loop.
460 uint64_t NumElements = Array->getSize().getZExtValue();
461 llvm::Value *Counter = CGF.Builder.CreateLoad(IndexVar);
462 llvm::Value *NumElementsPtr =
463 llvm::ConstantInt::get(Counter->getType(), NumElements);
464 llvm::Value *IsLess = CGF.Builder.CreateICmpULT(Counter, NumElementsPtr,
467 // If the condition is true, execute the body.
468 CGF.Builder.CreateCondBr(IsLess, ForBody, AfterFor);
470 CGF.EmitBlock(ForBody);
471 llvm::BasicBlock *ContinueBlock = CGF.createBasicBlock("for.inc");
474 CodeGenFunction::RunCleanupsScope Cleanups(CGF);
476 // Inside the loop body recurse to emit the inner loop or, eventually, the
478 EmitAggMemberInitializer(CGF, LHS, ArrayIndexVar, MemberInit,
479 Array->getElementType(), Index + 1);
482 CGF.EmitBlock(ContinueBlock);
484 // Emit the increment of the loop counter.
485 llvm::Value *NextVal = llvm::ConstantInt::get(Counter->getType(), 1);
486 Counter = CGF.Builder.CreateLoad(IndexVar);
487 NextVal = CGF.Builder.CreateAdd(Counter, NextVal, "inc");
488 CGF.Builder.CreateStore(NextVal, IndexVar);
490 // Finally, branch back up to the condition for the next iteration.
491 CGF.EmitBranch(CondBlock);
493 // Emit the fall-through block.
494 CGF.EmitBlock(AfterFor, true);
498 struct CallMemberDtor : EHScopeStack::Cleanup {
500 CXXDestructorDecl *Dtor;
502 CallMemberDtor(FieldDecl *Field, CXXDestructorDecl *Dtor)
503 : Field(Field), Dtor(Dtor) {}
505 void Emit(CodeGenFunction &CGF, bool IsForEH) {
506 // FIXME: Is this OK for C++0x delegating constructors?
507 llvm::Value *ThisPtr = CGF.LoadCXXThis();
508 LValue LHS = CGF.EmitLValueForField(ThisPtr, Field, 0);
510 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
516 static void EmitMemberInitializer(CodeGenFunction &CGF,
517 const CXXRecordDecl *ClassDecl,
518 CXXCtorInitializer *MemberInit,
519 const CXXConstructorDecl *Constructor,
520 FunctionArgList &Args) {
521 assert(MemberInit->isAnyMemberInitializer() &&
522 "Must have member initializer!");
523 assert(MemberInit->getInit() && "Must have initializer!");
525 // non-static data member initializers.
526 FieldDecl *Field = MemberInit->getAnyMember();
527 QualType FieldType = CGF.getContext().getCanonicalType(Field->getType());
529 llvm::Value *ThisPtr = CGF.LoadCXXThis();
532 // If we are initializing an anonymous union field, drill down to the field.
533 if (MemberInit->isIndirectMemberInitializer()) {
534 LHS = CGF.EmitLValueForAnonRecordField(ThisPtr,
535 MemberInit->getIndirectMember(), 0);
536 FieldType = MemberInit->getIndirectMember()->getAnonField()->getType();
538 LHS = CGF.EmitLValueForFieldInitialization(ThisPtr, Field, 0);
541 // FIXME: If there's no initializer and the CXXCtorInitializer
542 // was implicitly generated, we shouldn't be zeroing memory.
544 if (FieldType->isReferenceType()) {
545 RHS = CGF.EmitReferenceBindingToExpr(MemberInit->getInit(), Field);
546 CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
547 } else if (FieldType->isArrayType() && !MemberInit->getInit()) {
548 CGF.EmitNullInitialization(LHS.getAddress(), Field->getType());
549 } else if (!CGF.hasAggregateLLVMType(Field->getType())) {
550 RHS = RValue::get(CGF.EmitScalarExpr(MemberInit->getInit()));
551 CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
552 } else if (MemberInit->getInit()->getType()->isAnyComplexType()) {
553 CGF.EmitComplexExprIntoAddr(MemberInit->getInit(), LHS.getAddress(),
554 LHS.isVolatileQualified());
556 llvm::Value *ArrayIndexVar = 0;
557 const ConstantArrayType *Array
558 = CGF.getContext().getAsConstantArrayType(FieldType);
559 if (Array && Constructor->isImplicit() &&
560 Constructor->isCopyConstructor()) {
561 const llvm::Type *SizeTy
562 = CGF.ConvertType(CGF.getContext().getSizeType());
564 // The LHS is a pointer to the first object we'll be constructing, as
566 QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
567 const llvm::Type *BasePtr = CGF.ConvertType(BaseElementTy);
568 BasePtr = llvm::PointerType::getUnqual(BasePtr);
569 llvm::Value *BaseAddrPtr = CGF.Builder.CreateBitCast(LHS.getAddress(),
571 LHS = CGF.MakeAddrLValue(BaseAddrPtr, BaseElementTy);
573 // Create an array index that will be used to walk over all of the
574 // objects we're constructing.
575 ArrayIndexVar = CGF.CreateTempAlloca(SizeTy, "object.index");
576 llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy);
577 CGF.Builder.CreateStore(Zero, ArrayIndexVar);
579 // If we are copying an array of scalars or classes with trivial copy
580 // constructors, perform a single aggregate copy.
581 const RecordType *Record = BaseElementTy->getAs<RecordType>();
583 cast<CXXRecordDecl>(Record->getDecl())->hasTrivialCopyConstructor()) {
584 // Find the source pointer. We knows it's the last argument because
585 // we know we're in a copy constructor.
586 unsigned SrcArgIndex = Args.size() - 1;
588 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
589 LValue Src = CGF.EmitLValueForFieldInitialization(SrcPtr, Field, 0);
591 // Copy the aggregate.
592 CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType,
593 LHS.isVolatileQualified());
597 // Emit the block variables for the array indices, if any.
598 for (unsigned I = 0, N = MemberInit->getNumArrayIndices(); I != N; ++I)
599 CGF.EmitAutoVarDecl(*MemberInit->getArrayIndex(I));
602 EmitAggMemberInitializer(CGF, LHS, ArrayIndexVar, MemberInit, FieldType, 0);
604 if (!CGF.CGM.getLangOptions().Exceptions)
607 // FIXME: If we have an array of classes w/ non-trivial destructors,
608 // we need to destroy in reverse order of construction along the exception
610 const RecordType *RT = FieldType->getAs<RecordType>();
614 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
615 if (!RD->hasTrivialDestructor())
616 CGF.EHStack.pushCleanup<CallMemberDtor>(EHCleanup, Field,
617 RD->getDestructor());
621 /// Checks whether the given constructor is a valid subject for the
622 /// complete-to-base constructor delegation optimization, i.e.
623 /// emitting the complete constructor as a simple call to the base
625 static bool IsConstructorDelegationValid(const CXXConstructorDecl *Ctor) {
627 // Currently we disable the optimization for classes with virtual
628 // bases because (1) the addresses of parameter variables need to be
629 // consistent across all initializers but (2) the delegate function
630 // call necessarily creates a second copy of the parameter variable.
632 // The limiting example (purely theoretical AFAIK):
633 // struct A { A(int &c) { c++; } };
634 // struct B : virtual A {
635 // B(int count) : A(count) { printf("%d\n", count); }
637 // ...although even this example could in principle be emitted as a
638 // delegation since the address of the parameter doesn't escape.
639 if (Ctor->getParent()->getNumVBases()) {
640 // TODO: white-list trivial vbase initializers. This case wouldn't
641 // be subject to the restrictions below.
643 // TODO: white-list cases where:
644 // - there are no non-reference parameters to the constructor
645 // - the initializers don't access any non-reference parameters
646 // - the initializers don't take the address of non-reference
649 // If we ever add any of the above cases, remember that:
650 // - function-try-blocks will always blacklist this optimization
651 // - we need to perform the constructor prologue and cleanup in
652 // EmitConstructorBody.
657 // We also disable the optimization for variadic functions because
658 // it's impossible to "re-pass" varargs.
659 if (Ctor->getType()->getAs<FunctionProtoType>()->isVariadic())
662 // FIXME: Decide if we can do a delegation of a delegating constructor.
663 if (Ctor->isDelegatingConstructor())
669 /// EmitConstructorBody - Emits the body of the current constructor.
670 void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
671 const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
672 CXXCtorType CtorType = CurGD.getCtorType();
674 // Before we go any further, try the complete->base constructor
675 // delegation optimization.
676 if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor)) {
677 if (CGDebugInfo *DI = getDebugInfo())
678 DI->EmitStopPoint(Builder);
679 EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args);
683 Stmt *Body = Ctor->getBody();
685 // Enter the function-try-block before the constructor prologue if
687 bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
689 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
691 EHScopeStack::stable_iterator CleanupDepth = EHStack.stable_begin();
693 // Emit the constructor prologue, i.e. the base and member
695 EmitCtorPrologue(Ctor, CtorType, Args);
697 // Emit the body of the statement.
699 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
703 // Emit any cleanup blocks associated with the member or base
704 // initializers, which includes (along the exceptional path) the
705 // destructors for those members and bases that were fully
707 PopCleanupBlocks(CleanupDepth);
710 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
713 /// EmitCtorPrologue - This routine generates necessary code to initialize
714 /// base classes and non-static data members belonging to this constructor.
715 void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
716 CXXCtorType CtorType,
717 FunctionArgList &Args) {
718 if (CD->isDelegatingConstructor())
719 return EmitDelegatingCXXConstructorCall(CD, Args);
721 const CXXRecordDecl *ClassDecl = CD->getParent();
723 llvm::SmallVector<CXXCtorInitializer *, 8> MemberInitializers;
725 for (CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
728 CXXCtorInitializer *Member = (*B);
730 if (Member->isBaseInitializer()) {
731 EmitBaseInitializer(*this, ClassDecl, Member, CtorType);
733 assert(Member->isAnyMemberInitializer() &&
734 "Delegating initializer on non-delegating constructor");
735 MemberInitializers.push_back(Member);
739 InitializeVTablePointers(ClassDecl);
741 for (unsigned I = 0, E = MemberInitializers.size(); I != E; ++I)
742 EmitMemberInitializer(*this, ClassDecl, MemberInitializers[I], CD, Args);
746 FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field);
749 HasTrivialDestructorBody(ASTContext &Context,
750 const CXXRecordDecl *BaseClassDecl,
751 const CXXRecordDecl *MostDerivedClassDecl)
753 // If the destructor is trivial we don't have to check anything else.
754 if (BaseClassDecl->hasTrivialDestructor())
757 if (!BaseClassDecl->getDestructor()->hasTrivialBody())
761 for (CXXRecordDecl::field_iterator I = BaseClassDecl->field_begin(),
762 E = BaseClassDecl->field_end(); I != E; ++I) {
763 const FieldDecl *Field = *I;
765 if (!FieldHasTrivialDestructorBody(Context, Field))
769 // Check non-virtual bases.
770 for (CXXRecordDecl::base_class_const_iterator I =
771 BaseClassDecl->bases_begin(), E = BaseClassDecl->bases_end();
776 const CXXRecordDecl *NonVirtualBase =
777 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
778 if (!HasTrivialDestructorBody(Context, NonVirtualBase,
779 MostDerivedClassDecl))
783 if (BaseClassDecl == MostDerivedClassDecl) {
784 // Check virtual bases.
785 for (CXXRecordDecl::base_class_const_iterator I =
786 BaseClassDecl->vbases_begin(), E = BaseClassDecl->vbases_end();
788 const CXXRecordDecl *VirtualBase =
789 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
790 if (!HasTrivialDestructorBody(Context, VirtualBase,
791 MostDerivedClassDecl))
800 FieldHasTrivialDestructorBody(ASTContext &Context,
801 const FieldDecl *Field)
803 QualType FieldBaseElementType = Context.getBaseElementType(Field->getType());
805 const RecordType *RT = FieldBaseElementType->getAs<RecordType>();
809 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
810 return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl);
813 /// CanSkipVTablePointerInitialization - Check whether we need to initialize
814 /// any vtable pointers before calling this destructor.
815 static bool CanSkipVTablePointerInitialization(ASTContext &Context,
816 const CXXDestructorDecl *Dtor) {
817 if (!Dtor->hasTrivialBody())
821 const CXXRecordDecl *ClassDecl = Dtor->getParent();
822 for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
823 E = ClassDecl->field_end(); I != E; ++I) {
824 const FieldDecl *Field = *I;
826 if (!FieldHasTrivialDestructorBody(Context, Field))
833 /// EmitDestructorBody - Emits the body of the current destructor.
834 void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
835 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
836 CXXDtorType DtorType = CurGD.getDtorType();
838 // The call to operator delete in a deleting destructor happens
839 // outside of the function-try-block, which means it's always
840 // possible to delegate the destructor body to the complete
841 // destructor. Do so.
842 if (DtorType == Dtor_Deleting) {
843 EnterDtorCleanups(Dtor, Dtor_Deleting);
844 EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
850 Stmt *Body = Dtor->getBody();
852 // If the body is a function-try-block, enter the try before
854 bool isTryBody = (Body && isa<CXXTryStmt>(Body));
856 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
858 // Enter the epilogue cleanups.
859 RunCleanupsScope DtorEpilogue(*this);
861 // If this is the complete variant, just invoke the base variant;
862 // the epilogue will destruct the virtual bases. But we can't do
863 // this optimization if the body is a function-try-block, because
864 // we'd introduce *two* handler blocks.
866 case Dtor_Deleting: llvm_unreachable("already handled deleting case");
869 // Enter the cleanup scopes for virtual bases.
870 EnterDtorCleanups(Dtor, Dtor_Complete);
873 EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
877 // Fallthrough: act like we're in the base variant.
880 // Enter the cleanup scopes for fields and non-virtual bases.
881 EnterDtorCleanups(Dtor, Dtor_Base);
883 // Initialize the vtable pointers before entering the body.
884 if (!CanSkipVTablePointerInitialization(getContext(), Dtor))
885 InitializeVTablePointers(Dtor->getParent());
888 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
892 assert(Dtor->isImplicit() && "bodyless dtor not implicit");
893 // nothing to do besides what's in the epilogue
895 // -fapple-kext must inline any call to this dtor into
896 // the caller's body.
897 if (getContext().getLangOptions().AppleKext)
898 CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
902 // Jump out through the epilogue cleanups.
903 DtorEpilogue.ForceCleanup();
905 // Exit the try if applicable.
907 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
911 /// Call the operator delete associated with the current destructor.
912 struct CallDtorDelete : EHScopeStack::Cleanup {
915 void Emit(CodeGenFunction &CGF, bool IsForEH) {
916 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
917 const CXXRecordDecl *ClassDecl = Dtor->getParent();
918 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
919 CGF.getContext().getTagDeclType(ClassDecl));
923 struct CallArrayFieldDtor : EHScopeStack::Cleanup {
924 const FieldDecl *Field;
925 CallArrayFieldDtor(const FieldDecl *Field) : Field(Field) {}
927 void Emit(CodeGenFunction &CGF, bool IsForEH) {
928 QualType FieldType = Field->getType();
929 const ConstantArrayType *Array =
930 CGF.getContext().getAsConstantArrayType(FieldType);
933 CGF.getContext().getBaseElementType(Array->getElementType());
934 const CXXRecordDecl *FieldClassDecl = BaseType->getAsCXXRecordDecl();
936 llvm::Value *ThisPtr = CGF.LoadCXXThis();
937 LValue LHS = CGF.EmitLValueForField(ThisPtr, Field,
938 // FIXME: Qualifiers?
939 /*CVRQualifiers=*/0);
941 const llvm::Type *BasePtr = CGF.ConvertType(BaseType)->getPointerTo();
942 llvm::Value *BaseAddrPtr =
943 CGF.Builder.CreateBitCast(LHS.getAddress(), BasePtr);
944 CGF.EmitCXXAggrDestructorCall(FieldClassDecl->getDestructor(),
949 struct CallFieldDtor : EHScopeStack::Cleanup {
950 const FieldDecl *Field;
951 CallFieldDtor(const FieldDecl *Field) : Field(Field) {}
953 void Emit(CodeGenFunction &CGF, bool IsForEH) {
954 const CXXRecordDecl *FieldClassDecl =
955 Field->getType()->getAsCXXRecordDecl();
957 llvm::Value *ThisPtr = CGF.LoadCXXThis();
958 LValue LHS = CGF.EmitLValueForField(ThisPtr, Field,
959 // FIXME: Qualifiers?
960 /*CVRQualifiers=*/0);
962 CGF.EmitCXXDestructorCall(FieldClassDecl->getDestructor(),
963 Dtor_Complete, /*ForVirtualBase=*/false,
969 /// EmitDtorEpilogue - Emit all code that comes at the end of class's
970 /// destructor. This is to call destructors on members and base classes
971 /// in reverse order of their construction.
972 void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD,
973 CXXDtorType DtorType) {
974 assert(!DD->isTrivial() &&
975 "Should not emit dtor epilogue for trivial dtor!");
977 // The deleting-destructor phase just needs to call the appropriate
978 // operator delete that Sema picked up.
979 if (DtorType == Dtor_Deleting) {
980 assert(DD->getOperatorDelete() &&
981 "operator delete missing - EmitDtorEpilogue");
982 EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
986 const CXXRecordDecl *ClassDecl = DD->getParent();
988 // The complete-destructor phase just destructs all the virtual bases.
989 if (DtorType == Dtor_Complete) {
991 // We push them in the forward order so that they'll be popped in
992 // the reverse order.
993 for (CXXRecordDecl::base_class_const_iterator I =
994 ClassDecl->vbases_begin(), E = ClassDecl->vbases_end();
996 const CXXBaseSpecifier &Base = *I;
997 CXXRecordDecl *BaseClassDecl
998 = cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
1000 // Ignore trivial destructors.
1001 if (BaseClassDecl->hasTrivialDestructor())
1004 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1006 /*BaseIsVirtual*/ true);
1012 assert(DtorType == Dtor_Base);
1014 // Destroy non-virtual bases.
1015 for (CXXRecordDecl::base_class_const_iterator I =
1016 ClassDecl->bases_begin(), E = ClassDecl->bases_end(); I != E; ++I) {
1017 const CXXBaseSpecifier &Base = *I;
1019 // Ignore virtual bases.
1020 if (Base.isVirtual())
1023 CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
1025 // Ignore trivial destructors.
1026 if (BaseClassDecl->hasTrivialDestructor())
1029 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1031 /*BaseIsVirtual*/ false);
1034 // Destroy direct fields.
1035 llvm::SmallVector<const FieldDecl *, 16> FieldDecls;
1036 for (CXXRecordDecl::field_iterator I = ClassDecl->field_begin(),
1037 E = ClassDecl->field_end(); I != E; ++I) {
1038 const FieldDecl *Field = *I;
1040 QualType FieldType = getContext().getCanonicalType(Field->getType());
1041 const ConstantArrayType *Array =
1042 getContext().getAsConstantArrayType(FieldType);
1044 FieldType = getContext().getBaseElementType(Array->getElementType());
1046 const RecordType *RT = FieldType->getAs<RecordType>();
1050 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
1051 if (FieldClassDecl->hasTrivialDestructor())
1055 EHStack.pushCleanup<CallArrayFieldDtor>(NormalAndEHCleanup, Field);
1057 EHStack.pushCleanup<CallFieldDtor>(NormalAndEHCleanup, Field);
1061 /// EmitCXXAggrConstructorCall - This routine essentially creates a (nested)
1062 /// for-loop to call the default constructor on individual members of the
1064 /// 'D' is the default constructor for elements of the array, 'ArrayTy' is the
1065 /// array type and 'ArrayPtr' points to the beginning fo the array.
1066 /// It is assumed that all relevant checks have been made by the caller.
1068 /// \param ZeroInitialization True if each element should be zero-initialized
1069 /// before it is constructed.
1071 CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D,
1072 const ConstantArrayType *ArrayTy,
1073 llvm::Value *ArrayPtr,
1074 CallExpr::const_arg_iterator ArgBeg,
1075 CallExpr::const_arg_iterator ArgEnd,
1076 bool ZeroInitialization) {
1078 const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1079 llvm::Value * NumElements =
1080 llvm::ConstantInt::get(SizeTy,
1081 getContext().getConstantArrayElementCount(ArrayTy));
1083 EmitCXXAggrConstructorCall(D, NumElements, ArrayPtr, ArgBeg, ArgEnd,
1084 ZeroInitialization);
1088 CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D,
1089 llvm::Value *NumElements,
1090 llvm::Value *ArrayPtr,
1091 CallExpr::const_arg_iterator ArgBeg,
1092 CallExpr::const_arg_iterator ArgEnd,
1093 bool ZeroInitialization) {
1094 const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
1096 // Create a temporary for the loop index and initialize it with 0.
1097 llvm::Value *IndexPtr = CreateTempAlloca(SizeTy, "loop.index");
1098 llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy);
1099 Builder.CreateStore(Zero, IndexPtr);
1101 // Start the loop with a block that tests the condition.
1102 llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
1103 llvm::BasicBlock *AfterFor = createBasicBlock("for.end");
1105 EmitBlock(CondBlock);
1107 llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1109 // Generate: if (loop-index < number-of-elements fall to the loop body,
1110 // otherwise, go to the block after the for-loop.
1111 llvm::Value *Counter = Builder.CreateLoad(IndexPtr);
1112 llvm::Value *IsLess = Builder.CreateICmpULT(Counter, NumElements, "isless");
1113 // If the condition is true, execute the body.
1114 Builder.CreateCondBr(IsLess, ForBody, AfterFor);
1118 llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc");
1119 // Inside the loop body, emit the constructor call on the array element.
1120 Counter = Builder.CreateLoad(IndexPtr);
1121 llvm::Value *Address = Builder.CreateInBoundsGEP(ArrayPtr, Counter,
1124 // Zero initialize the storage, if requested.
1125 if (ZeroInitialization)
1126 EmitNullInitialization(Address,
1127 getContext().getTypeDeclType(D->getParent()));
1129 // C++ [class.temporary]p4:
1130 // There are two contexts in which temporaries are destroyed at a different
1131 // point than the end of the full-expression. The first context is when a
1132 // default constructor is called to initialize an element of an array.
1133 // If the constructor has one or more default arguments, the destruction of
1134 // every temporary created in a default argument expression is sequenced
1135 // before the construction of the next array element, if any.
1137 // Keep track of the current number of live temporaries.
1139 RunCleanupsScope Scope(*this);
1141 EmitCXXConstructorCall(D, Ctor_Complete, /*ForVirtualBase=*/false, Address,
1145 EmitBlock(ContinueBlock);
1147 // Emit the increment of the loop counter.
1148 llvm::Value *NextVal = llvm::ConstantInt::get(SizeTy, 1);
1149 Counter = Builder.CreateLoad(IndexPtr);
1150 NextVal = Builder.CreateAdd(Counter, NextVal, "inc");
1151 Builder.CreateStore(NextVal, IndexPtr);
1153 // Finally, branch back up to the condition for the next iteration.
1154 EmitBranch(CondBlock);
1156 // Emit the fall-through block.
1157 EmitBlock(AfterFor, true);
1160 /// EmitCXXAggrDestructorCall - calls the default destructor on array
1161 /// elements in reverse order of construction.
1163 CodeGenFunction::EmitCXXAggrDestructorCall(const CXXDestructorDecl *D,
1164 const ArrayType *Array,
1165 llvm::Value *This) {
1166 const ConstantArrayType *CA = dyn_cast<ConstantArrayType>(Array);
1167 assert(CA && "Do we support VLA for destruction ?");
1168 uint64_t ElementCount = getContext().getConstantArrayElementCount(CA);
1170 const llvm::Type *SizeLTy = ConvertType(getContext().getSizeType());
1171 llvm::Value* ElementCountPtr = llvm::ConstantInt::get(SizeLTy, ElementCount);
1172 EmitCXXAggrDestructorCall(D, ElementCountPtr, This);
1175 /// EmitCXXAggrDestructorCall - calls the default destructor on array
1176 /// elements in reverse order of construction.
1178 CodeGenFunction::EmitCXXAggrDestructorCall(const CXXDestructorDecl *D,
1179 llvm::Value *UpperCount,
1180 llvm::Value *This) {
1181 const llvm::Type *SizeLTy = ConvertType(getContext().getSizeType());
1182 llvm::Value *One = llvm::ConstantInt::get(SizeLTy, 1);
1184 // Create a temporary for the loop index and initialize it with count of
1186 llvm::Value *IndexPtr = CreateTempAlloca(SizeLTy, "loop.index");
1188 // Store the number of elements in the index pointer.
1189 Builder.CreateStore(UpperCount, IndexPtr);
1191 // Start the loop with a block that tests the condition.
1192 llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
1193 llvm::BasicBlock *AfterFor = createBasicBlock("for.end");
1195 EmitBlock(CondBlock);
1197 llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1199 // Generate: if (loop-index != 0 fall to the loop body,
1200 // otherwise, go to the block after the for-loop.
1201 llvm::Value* zeroConstant =
1202 llvm::Constant::getNullValue(SizeLTy);
1203 llvm::Value *Counter = Builder.CreateLoad(IndexPtr);
1204 llvm::Value *IsNE = Builder.CreateICmpNE(Counter, zeroConstant,
1206 // If the condition is true, execute the body.
1207 Builder.CreateCondBr(IsNE, ForBody, AfterFor);
1211 llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc");
1212 // Inside the loop body, emit the constructor call on the array element.
1213 Counter = Builder.CreateLoad(IndexPtr);
1214 Counter = Builder.CreateSub(Counter, One);
1215 llvm::Value *Address = Builder.CreateInBoundsGEP(This, Counter, "arrayidx");
1216 EmitCXXDestructorCall(D, Dtor_Complete, /*ForVirtualBase=*/false, Address);
1218 EmitBlock(ContinueBlock);
1220 // Emit the decrement of the loop counter.
1221 Counter = Builder.CreateLoad(IndexPtr);
1222 Counter = Builder.CreateSub(Counter, One, "dec");
1223 Builder.CreateStore(Counter, IndexPtr);
1225 // Finally, branch back up to the condition for the next iteration.
1226 EmitBranch(CondBlock);
1228 // Emit the fall-through block.
1229 EmitBlock(AfterFor, true);
1233 CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
1234 CXXCtorType Type, bool ForVirtualBase,
1236 CallExpr::const_arg_iterator ArgBeg,
1237 CallExpr::const_arg_iterator ArgEnd) {
1239 CGDebugInfo *DI = getDebugInfo();
1240 if (DI && CGM.getCodeGenOpts().LimitDebugInfo) {
1241 // If debug info for this class has been emitted then this is the right time
1243 const CXXRecordDecl *Parent = D->getParent();
1244 DI->getOrCreateRecordType(CGM.getContext().getTypeDeclType(Parent),
1245 Parent->getLocation());
1248 if (D->isTrivial()) {
1249 if (ArgBeg == ArgEnd) {
1250 // Trivial default constructor, no codegen required.
1251 assert(D->isDefaultConstructor() &&
1252 "trivial 0-arg ctor not a default ctor");
1256 assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
1257 assert(D->isCopyConstructor() && "trivial 1-arg ctor not a copy ctor");
1259 const Expr *E = (*ArgBeg);
1260 QualType Ty = E->getType();
1261 llvm::Value *Src = EmitLValue(E).getAddress();
1262 EmitAggregateCopy(This, Src, Ty);
1266 llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(D, Type), ForVirtualBase);
1267 llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Type);
1269 EmitCXXMemberCall(D, Callee, ReturnValueSlot(), This, VTT, ArgBeg, ArgEnd);
1273 CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
1274 llvm::Value *This, llvm::Value *Src,
1275 CallExpr::const_arg_iterator ArgBeg,
1276 CallExpr::const_arg_iterator ArgEnd) {
1277 if (D->isTrivial()) {
1278 assert(ArgBeg + 1 == ArgEnd && "unexpected argcount for trivial ctor");
1279 assert(D->isCopyConstructor() && "trivial 1-arg ctor not a copy ctor");
1280 EmitAggregateCopy(This, Src, (*ArgBeg)->getType());
1283 llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D,
1284 clang::Ctor_Complete);
1285 assert(D->isInstance() &&
1286 "Trying to emit a member call expr on a static method!");
1288 const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
1292 // Push the this ptr.
1293 Args.add(RValue::get(This), D->getThisType(getContext()));
1296 // Push the src ptr.
1297 QualType QT = *(FPT->arg_type_begin());
1298 const llvm::Type *t = CGM.getTypes().ConvertType(QT);
1299 Src = Builder.CreateBitCast(Src, t);
1300 Args.add(RValue::get(Src), QT);
1302 // Skip over first argument (Src).
1304 CallExpr::const_arg_iterator Arg = ArgBeg;
1305 for (FunctionProtoType::arg_type_iterator I = FPT->arg_type_begin()+1,
1306 E = FPT->arg_type_end(); I != E; ++I, ++Arg) {
1307 assert(Arg != ArgEnd && "Running over edge of argument list!");
1308 EmitCallArg(Args, *Arg, *I);
1310 // Either we've emitted all the call args, or we have a call to a
1311 // variadic function.
1312 assert((Arg == ArgEnd || FPT->isVariadic()) &&
1313 "Extra arguments in non-variadic function!");
1314 // If we still have any arguments, emit them using the type of the argument.
1315 for (; Arg != ArgEnd; ++Arg) {
1316 QualType ArgType = Arg->getType();
1317 EmitCallArg(Args, *Arg, ArgType);
1320 QualType ResultType = FPT->getResultType();
1321 EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args,
1323 Callee, ReturnValueSlot(), Args, D);
1327 CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
1328 CXXCtorType CtorType,
1329 const FunctionArgList &Args) {
1330 CallArgList DelegateArgs;
1332 FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
1333 assert(I != E && "no parameters to constructor");
1336 DelegateArgs.add(RValue::get(LoadCXXThis()), (*I)->getType());
1340 if (llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(Ctor, CtorType),
1341 /*ForVirtualBase=*/false)) {
1342 QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy);
1343 DelegateArgs.add(RValue::get(VTT), VoidPP);
1345 if (CodeGenVTables::needsVTTParameter(CurGD)) {
1346 assert(I != E && "cannot skip vtt parameter, already done with args");
1347 assert((*I)->getType() == VoidPP && "skipping parameter not of vtt type");
1352 // Explicit arguments.
1353 for (; I != E; ++I) {
1354 const VarDecl *param = *I;
1355 EmitDelegateCallArg(DelegateArgs, param);
1358 EmitCall(CGM.getTypes().getFunctionInfo(Ctor, CtorType),
1359 CGM.GetAddrOfCXXConstructor(Ctor, CtorType),
1360 ReturnValueSlot(), DelegateArgs, Ctor);
1364 struct CallDelegatingCtorDtor : EHScopeStack::Cleanup {
1365 const CXXDestructorDecl *Dtor;
1369 CallDelegatingCtorDtor(const CXXDestructorDecl *D, llvm::Value *Addr,
1371 : Dtor(D), Addr(Addr), Type(Type) {}
1373 void Emit(CodeGenFunction &CGF, bool IsForEH) {
1374 CGF.EmitCXXDestructorCall(Dtor, Type, /*ForVirtualBase=*/false,
1381 CodeGenFunction::EmitDelegatingCXXConstructorCall(const CXXConstructorDecl *Ctor,
1382 const FunctionArgList &Args) {
1383 assert(Ctor->isDelegatingConstructor());
1385 llvm::Value *ThisPtr = LoadCXXThis();
1387 AggValueSlot AggSlot = AggValueSlot::forAddr(ThisPtr, false, /*Lifetime*/ true);
1389 EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot);
1391 const CXXRecordDecl *ClassDecl = Ctor->getParent();
1392 if (CGM.getLangOptions().Exceptions && !ClassDecl->hasTrivialDestructor()) {
1394 CurGD.getCtorType() == Ctor_Complete ? Dtor_Complete : Dtor_Base;
1396 EHStack.pushCleanup<CallDelegatingCtorDtor>(EHCleanup,
1397 ClassDecl->getDestructor(),
1402 void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
1404 bool ForVirtualBase,
1405 llvm::Value *This) {
1406 llvm::Value *VTT = GetVTTParameter(*this, GlobalDecl(DD, Type),
1408 llvm::Value *Callee = 0;
1409 if (getContext().getLangOptions().AppleKext)
1410 Callee = BuildAppleKextVirtualDestructorCall(DD, Type,
1414 Callee = CGM.GetAddrOfCXXDestructor(DD, Type);
1416 EmitCXXMemberCall(DD, Callee, ReturnValueSlot(), This, VTT, 0, 0);
1420 struct CallLocalDtor : EHScopeStack::Cleanup {
1421 const CXXDestructorDecl *Dtor;
1424 CallLocalDtor(const CXXDestructorDecl *D, llvm::Value *Addr)
1425 : Dtor(D), Addr(Addr) {}
1427 void Emit(CodeGenFunction &CGF, bool IsForEH) {
1428 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1429 /*ForVirtualBase=*/false, Addr);
1434 void CodeGenFunction::PushDestructorCleanup(const CXXDestructorDecl *D,
1435 llvm::Value *Addr) {
1436 EHStack.pushCleanup<CallLocalDtor>(NormalAndEHCleanup, D, Addr);
1439 void CodeGenFunction::PushDestructorCleanup(QualType T, llvm::Value *Addr) {
1440 CXXRecordDecl *ClassDecl = T->getAsCXXRecordDecl();
1441 if (!ClassDecl) return;
1442 if (ClassDecl->hasTrivialDestructor()) return;
1444 const CXXDestructorDecl *D = ClassDecl->getDestructor();
1445 assert(D && D->isUsed() && "destructor not marked as used!");
1446 PushDestructorCleanup(D, Addr);
1450 CodeGenFunction::GetVirtualBaseClassOffset(llvm::Value *This,
1451 const CXXRecordDecl *ClassDecl,
1452 const CXXRecordDecl *BaseClassDecl) {
1453 llvm::Value *VTablePtr = GetVTablePtr(This, Int8PtrTy);
1454 CharUnits VBaseOffsetOffset =
1455 CGM.getVTables().getVirtualBaseOffsetOffset(ClassDecl, BaseClassDecl);
1457 llvm::Value *VBaseOffsetPtr =
1458 Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset.getQuantity(),
1459 "vbase.offset.ptr");
1460 const llvm::Type *PtrDiffTy =
1461 ConvertType(getContext().getPointerDiffType());
1463 VBaseOffsetPtr = Builder.CreateBitCast(VBaseOffsetPtr,
1464 PtrDiffTy->getPointerTo());
1466 llvm::Value *VBaseOffset = Builder.CreateLoad(VBaseOffsetPtr, "vbase.offset");
1472 CodeGenFunction::InitializeVTablePointer(BaseSubobject Base,
1473 const CXXRecordDecl *NearestVBase,
1474 CharUnits OffsetFromNearestVBase,
1475 llvm::Constant *VTable,
1476 const CXXRecordDecl *VTableClass) {
1477 const CXXRecordDecl *RD = Base.getBase();
1479 // Compute the address point.
1480 llvm::Value *VTableAddressPoint;
1482 // Check if we need to use a vtable from the VTT.
1483 if (CodeGenVTables::needsVTTParameter(CurGD) &&
1484 (RD->getNumVBases() || NearestVBase)) {
1485 // Get the secondary vpointer index.
1486 uint64_t VirtualPointerIndex =
1487 CGM.getVTables().getSecondaryVirtualPointerIndex(VTableClass, Base);
1490 llvm::Value *VTT = LoadCXXVTT();
1491 if (VirtualPointerIndex)
1492 VTT = Builder.CreateConstInBoundsGEP1_64(VTT, VirtualPointerIndex);
1494 // And load the address point from the VTT.
1495 VTableAddressPoint = Builder.CreateLoad(VTT);
1497 uint64_t AddressPoint = CGM.getVTables().getAddressPoint(Base, VTableClass);
1498 VTableAddressPoint =
1499 Builder.CreateConstInBoundsGEP2_64(VTable, 0, AddressPoint);
1502 // Compute where to store the address point.
1503 llvm::Value *VirtualOffset = 0;
1504 CharUnits NonVirtualOffset = CharUnits::Zero();
1506 if (CodeGenVTables::needsVTTParameter(CurGD) && NearestVBase) {
1507 // We need to use the virtual base offset offset because the virtual base
1508 // might have a different offset in the most derived class.
1509 VirtualOffset = GetVirtualBaseClassOffset(LoadCXXThis(), VTableClass,
1511 NonVirtualOffset = OffsetFromNearestVBase;
1513 // We can just use the base offset in the complete class.
1514 NonVirtualOffset = Base.getBaseOffset();
1517 // Apply the offsets.
1518 llvm::Value *VTableField = LoadCXXThis();
1520 if (!NonVirtualOffset.isZero() || VirtualOffset)
1521 VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField,
1525 // Finally, store the address point.
1526 const llvm::Type *AddressPointPtrTy =
1527 VTableAddressPoint->getType()->getPointerTo();
1528 VTableField = Builder.CreateBitCast(VTableField, AddressPointPtrTy);
1529 Builder.CreateStore(VTableAddressPoint, VTableField);
1533 CodeGenFunction::InitializeVTablePointers(BaseSubobject Base,
1534 const CXXRecordDecl *NearestVBase,
1535 CharUnits OffsetFromNearestVBase,
1536 bool BaseIsNonVirtualPrimaryBase,
1537 llvm::Constant *VTable,
1538 const CXXRecordDecl *VTableClass,
1539 VisitedVirtualBasesSetTy& VBases) {
1540 // If this base is a non-virtual primary base the address point has already
1542 if (!BaseIsNonVirtualPrimaryBase) {
1543 // Initialize the vtable pointer for this base.
1544 InitializeVTablePointer(Base, NearestVBase, OffsetFromNearestVBase,
1545 VTable, VTableClass);
1548 const CXXRecordDecl *RD = Base.getBase();
1551 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
1552 E = RD->bases_end(); I != E; ++I) {
1553 CXXRecordDecl *BaseDecl
1554 = cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
1556 // Ignore classes without a vtable.
1557 if (!BaseDecl->isDynamicClass())
1560 CharUnits BaseOffset;
1561 CharUnits BaseOffsetFromNearestVBase;
1562 bool BaseDeclIsNonVirtualPrimaryBase;
1564 if (I->isVirtual()) {
1565 // Check if we've visited this virtual base before.
1566 if (!VBases.insert(BaseDecl))
1569 const ASTRecordLayout &Layout =
1570 getContext().getASTRecordLayout(VTableClass);
1572 BaseOffset = Layout.getVBaseClassOffset(BaseDecl);
1573 BaseOffsetFromNearestVBase = CharUnits::Zero();
1574 BaseDeclIsNonVirtualPrimaryBase = false;
1576 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1578 BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl);
1579 BaseOffsetFromNearestVBase =
1580 OffsetFromNearestVBase + Layout.getBaseClassOffset(BaseDecl);
1581 BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl;
1584 InitializeVTablePointers(BaseSubobject(BaseDecl, BaseOffset),
1585 I->isVirtual() ? BaseDecl : NearestVBase,
1586 BaseOffsetFromNearestVBase,
1587 BaseDeclIsNonVirtualPrimaryBase,
1588 VTable, VTableClass, VBases);
1592 void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
1593 // Ignore classes without a vtable.
1594 if (!RD->isDynamicClass())
1598 llvm::Constant *VTable = CGM.getVTables().GetAddrOfVTable(RD);
1600 // Initialize the vtable pointers for this class and all of its bases.
1601 VisitedVirtualBasesSetTy VBases;
1602 InitializeVTablePointers(BaseSubobject(RD, CharUnits::Zero()),
1604 /*OffsetFromNearestVBase=*/CharUnits::Zero(),
1605 /*BaseIsNonVirtualPrimaryBase=*/false,
1606 VTable, RD, VBases);
1609 llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
1610 const llvm::Type *Ty) {
1611 llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo());
1612 return Builder.CreateLoad(VTablePtrSrc, "vtable");
1615 static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) {
1616 const Expr *E = Base;
1619 E = E->IgnoreParens();
1620 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
1621 if (CE->getCastKind() == CK_DerivedToBase ||
1622 CE->getCastKind() == CK_UncheckedDerivedToBase ||
1623 CE->getCastKind() == CK_NoOp) {
1624 E = CE->getSubExpr();
1632 QualType DerivedType = E->getType();
1633 if (const PointerType *PTy = DerivedType->getAs<PointerType>())
1634 DerivedType = PTy->getPointeeType();
1636 return cast<CXXRecordDecl>(DerivedType->castAs<RecordType>()->getDecl());
1639 // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do
1640 // quite what we want.
1641 static const Expr *skipNoOpCastsAndParens(const Expr *E) {
1643 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
1644 E = PE->getSubExpr();
1648 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
1649 if (CE->getCastKind() == CK_NoOp) {
1650 E = CE->getSubExpr();
1654 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
1655 if (UO->getOpcode() == UO_Extension) {
1656 E = UO->getSubExpr();
1664 /// canDevirtualizeMemberFunctionCall - Checks whether the given virtual member
1665 /// function call on the given expr can be devirtualized.
1666 /// expr can be devirtualized.
1667 static bool canDevirtualizeMemberFunctionCall(const Expr *Base,
1668 const CXXMethodDecl *MD) {
1669 // If the most derived class is marked final, we know that no subclass can
1670 // override this member function and so we can devirtualize it. For example:
1672 // struct A { virtual void f(); }
1673 // struct B final : A { };
1679 const CXXRecordDecl *MostDerivedClassDecl = getMostDerivedClassDecl(Base);
1680 if (MostDerivedClassDecl->hasAttr<FinalAttr>())
1683 // If the member function is marked 'final', we know that it can't be
1684 // overridden and can therefore devirtualize it.
1685 if (MD->hasAttr<FinalAttr>())
1688 // Similarly, if the class itself is marked 'final' it can't be overridden
1689 // and we can therefore devirtualize the member function call.
1690 if (MD->getParent()->hasAttr<FinalAttr>())
1693 Base = skipNoOpCastsAndParens(Base);
1694 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
1695 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
1696 // This is a record decl. We know the type and can devirtualize it.
1697 return VD->getType()->isRecordType();
1703 // We can always devirtualize calls on temporary object expressions.
1704 if (isa<CXXConstructExpr>(Base))
1707 // And calls on bound temporaries.
1708 if (isa<CXXBindTemporaryExpr>(Base))
1711 // Check if this is a call expr that returns a record type.
1712 if (const CallExpr *CE = dyn_cast<CallExpr>(Base))
1713 return CE->getCallReturnType()->isRecordType();
1715 // We can't devirtualize the call.
1719 static bool UseVirtualCall(ASTContext &Context,
1720 const CXXOperatorCallExpr *CE,
1721 const CXXMethodDecl *MD) {
1722 if (!MD->isVirtual())
1725 // When building with -fapple-kext, all calls must go through the vtable since
1726 // the kernel linker can do runtime patching of vtables.
1727 if (Context.getLangOptions().AppleKext)
1730 return !canDevirtualizeMemberFunctionCall(CE->getArg(0), MD);
1734 CodeGenFunction::EmitCXXOperatorMemberCallee(const CXXOperatorCallExpr *E,
1735 const CXXMethodDecl *MD,
1736 llvm::Value *This) {
1737 const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
1738 const llvm::Type *Ty =
1739 CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
1742 if (UseVirtualCall(getContext(), E, MD))
1743 return BuildVirtualCall(MD, This, Ty);
1745 return CGM.GetAddrOfFunction(MD, Ty);