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Diffstat (limited to 'clang/lib/CodeGen/CGExprAgg.cpp')
| -rw-r--r-- | clang/lib/CodeGen/CGExprAgg.cpp | 1343 |
1 files changed, 1343 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp new file mode 100644 index 0000000..7b0e0f5 --- /dev/null +++ b/clang/lib/CodeGen/CGExprAgg.cpp @@ -0,0 +1,1343 @@ +//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This contains code to emit Aggregate Expr nodes as LLVM code. +// +//===----------------------------------------------------------------------===// + +#include "CodeGenFunction.h" +#include "CodeGenModule.h" +#include "CGObjCRuntime.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/DeclTemplate.h" +#include "clang/AST/StmtVisitor.h" +#include "llvm/Constants.h" +#include "llvm/Function.h" +#include "llvm/GlobalVariable.h" +#include "llvm/Intrinsics.h" +using namespace clang; +using namespace CodeGen; + +//===----------------------------------------------------------------------===// +// Aggregate Expression Emitter +//===----------------------------------------------------------------------===// + +namespace { +class AggExprEmitter : public StmtVisitor<AggExprEmitter> { + CodeGenFunction &CGF; + CGBuilderTy &Builder; + AggValueSlot Dest; + bool IgnoreResult; + + /// We want to use 'dest' as the return slot except under two + /// conditions: + /// - The destination slot requires garbage collection, so we + /// need to use the GC API. + /// - The destination slot is potentially aliased. + bool shouldUseDestForReturnSlot() const { + return !(Dest.requiresGCollection() || Dest.isPotentiallyAliased()); + } + + ReturnValueSlot getReturnValueSlot() const { + if (!shouldUseDestForReturnSlot()) + return ReturnValueSlot(); + + return ReturnValueSlot(Dest.getAddr(), Dest.isVolatile()); + } + + AggValueSlot EnsureSlot(QualType T) { + if (!Dest.isIgnored()) return Dest; + return CGF.CreateAggTemp(T, "agg.tmp.ensured"); + } + +public: + AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, + bool ignore) + : CGF(cgf), Builder(CGF.Builder), Dest(Dest), + IgnoreResult(ignore) { + } + + //===--------------------------------------------------------------------===// + // Utilities + //===--------------------------------------------------------------------===// + + /// EmitAggLoadOfLValue - Given an expression with aggregate type that + /// represents a value lvalue, this method emits the address of the lvalue, + /// then loads the result into DestPtr. + void EmitAggLoadOfLValue(const Expr *E); + + /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. + void EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore = false); + void EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore = false, + unsigned Alignment = 0); + + void EmitMoveFromReturnSlot(const Expr *E, RValue Src); + + void EmitStdInitializerList(llvm::Value *DestPtr, InitListExpr *InitList); + void EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType, + QualType elementType, InitListExpr *E); + + AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) { + if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T)) + return AggValueSlot::NeedsGCBarriers; + return AggValueSlot::DoesNotNeedGCBarriers; + } + + bool TypeRequiresGCollection(QualType T); + + //===--------------------------------------------------------------------===// + // Visitor Methods + //===--------------------------------------------------------------------===// + + void VisitStmt(Stmt *S) { + CGF.ErrorUnsupported(S, "aggregate expression"); + } + void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); } + void VisitGenericSelectionExpr(GenericSelectionExpr *GE) { + Visit(GE->getResultExpr()); + } + void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); } + void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) { + return Visit(E->getReplacement()); + } + + // l-values. + void VisitDeclRefExpr(DeclRefExpr *E) { + // For aggregates, we should always be able to emit the variable + // as an l-value unless it's a reference. This is due to the fact + // that we can't actually ever see a normal l2r conversion on an + // aggregate in C++, and in C there's no language standard + // actively preventing us from listing variables in the captures + // list of a block. + if (E->getDecl()->getType()->isReferenceType()) { + if (CodeGenFunction::ConstantEmission result + = CGF.tryEmitAsConstant(E)) { + EmitFinalDestCopy(E, result.getReferenceLValue(CGF, E)); + return; + } + } + + EmitAggLoadOfLValue(E); + } + + void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); } + void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); } + void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); } + void VisitCompoundLiteralExpr(CompoundLiteralExpr *E); + void VisitArraySubscriptExpr(ArraySubscriptExpr *E) { + EmitAggLoadOfLValue(E); + } + void VisitPredefinedExpr(const PredefinedExpr *E) { + EmitAggLoadOfLValue(E); + } + + // Operators. + void VisitCastExpr(CastExpr *E); + void VisitCallExpr(const CallExpr *E); + void VisitStmtExpr(const StmtExpr *E); + void VisitBinaryOperator(const BinaryOperator *BO); + void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO); + void VisitBinAssign(const BinaryOperator *E); + void VisitBinComma(const BinaryOperator *E); + + void VisitObjCMessageExpr(ObjCMessageExpr *E); + void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { + EmitAggLoadOfLValue(E); + } + + void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO); + void VisitChooseExpr(const ChooseExpr *CE); + void VisitInitListExpr(InitListExpr *E); + void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E); + void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { + Visit(DAE->getExpr()); + } + void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E); + void VisitCXXConstructExpr(const CXXConstructExpr *E); + void VisitLambdaExpr(LambdaExpr *E); + void VisitExprWithCleanups(ExprWithCleanups *E); + void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E); + void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); } + void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E); + void VisitOpaqueValueExpr(OpaqueValueExpr *E); + + void VisitPseudoObjectExpr(PseudoObjectExpr *E) { + if (E->isGLValue()) { + LValue LV = CGF.EmitPseudoObjectLValue(E); + return EmitFinalDestCopy(E, LV); + } + + CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType())); + } + + void VisitVAArgExpr(VAArgExpr *E); + + void EmitInitializationToLValue(Expr *E, LValue Address); + void EmitNullInitializationToLValue(LValue Address); + // case Expr::ChooseExprClass: + void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); } + void VisitAtomicExpr(AtomicExpr *E) { + CGF.EmitAtomicExpr(E, EnsureSlot(E->getType()).getAddr()); + } +}; +} // end anonymous namespace. + +//===----------------------------------------------------------------------===// +// Utilities +//===----------------------------------------------------------------------===// + +/// EmitAggLoadOfLValue - Given an expression with aggregate type that +/// represents a value lvalue, this method emits the address of the lvalue, +/// then loads the result into DestPtr. +void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) { + LValue LV = CGF.EmitLValue(E); + EmitFinalDestCopy(E, LV); +} + +/// \brief True if the given aggregate type requires special GC API calls. +bool AggExprEmitter::TypeRequiresGCollection(QualType T) { + // Only record types have members that might require garbage collection. + const RecordType *RecordTy = T->getAs<RecordType>(); + if (!RecordTy) return false; + + // Don't mess with non-trivial C++ types. + RecordDecl *Record = RecordTy->getDecl(); + if (isa<CXXRecordDecl>(Record) && + (!cast<CXXRecordDecl>(Record)->hasTrivialCopyConstructor() || + !cast<CXXRecordDecl>(Record)->hasTrivialDestructor())) + return false; + + // Check whether the type has an object member. + return Record->hasObjectMember(); +} + +/// \brief Perform the final move to DestPtr if for some reason +/// getReturnValueSlot() didn't use it directly. +/// +/// The idea is that you do something like this: +/// RValue Result = EmitSomething(..., getReturnValueSlot()); +/// EmitMoveFromReturnSlot(E, Result); +/// +/// If nothing interferes, this will cause the result to be emitted +/// directly into the return value slot. Otherwise, a final move +/// will be performed. +void AggExprEmitter::EmitMoveFromReturnSlot(const Expr *E, RValue Src) { + if (shouldUseDestForReturnSlot()) { + // Logically, Dest.getAddr() should equal Src.getAggregateAddr(). + // The possibility of undef rvalues complicates that a lot, + // though, so we can't really assert. + return; + } + + // Otherwise, do a final copy, + assert(Dest.getAddr() != Src.getAggregateAddr()); + std::pair<CharUnits, CharUnits> TypeInfo = + CGF.getContext().getTypeInfoInChars(E->getType()); + CharUnits Alignment = std::min(TypeInfo.second, Dest.getAlignment()); + EmitFinalDestCopy(E, Src, /*Ignore*/ true, Alignment.getQuantity()); +} + +/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. +void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore, + unsigned Alignment) { + assert(Src.isAggregate() && "value must be aggregate value!"); + + // If Dest is ignored, then we're evaluating an aggregate expression + // in a context (like an expression statement) that doesn't care + // about the result. C says that an lvalue-to-rvalue conversion is + // performed in these cases; C++ says that it is not. In either + // case, we don't actually need to do anything unless the value is + // volatile. + if (Dest.isIgnored()) { + if (!Src.isVolatileQualified() || + CGF.CGM.getLangOpts().CPlusPlus || + (IgnoreResult && Ignore)) + return; + + // If the source is volatile, we must read from it; to do that, we need + // some place to put it. + Dest = CGF.CreateAggTemp(E->getType(), "agg.tmp"); + } + + if (Dest.requiresGCollection()) { + CharUnits size = CGF.getContext().getTypeSizeInChars(E->getType()); + llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType()); + llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity()); + CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, + Dest.getAddr(), + Src.getAggregateAddr(), + SizeVal); + return; + } + // If the result of the assignment is used, copy the LHS there also. + // FIXME: Pass VolatileDest as well. I think we also need to merge volatile + // from the source as well, as we can't eliminate it if either operand + // is volatile, unless copy has volatile for both source and destination.. + CGF.EmitAggregateCopy(Dest.getAddr(), Src.getAggregateAddr(), E->getType(), + Dest.isVolatile()|Src.isVolatileQualified(), + Alignment); +} + +/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. +void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) { + assert(Src.isSimple() && "Can't have aggregate bitfield, vector, etc"); + + CharUnits Alignment = std::min(Src.getAlignment(), Dest.getAlignment()); + EmitFinalDestCopy(E, Src.asAggregateRValue(), Ignore, Alignment.getQuantity()); +} + +static QualType GetStdInitializerListElementType(QualType T) { + // Just assume that this is really std::initializer_list. + ClassTemplateSpecializationDecl *specialization = + cast<ClassTemplateSpecializationDecl>(T->castAs<RecordType>()->getDecl()); + return specialization->getTemplateArgs()[0].getAsType(); +} + +/// \brief Prepare cleanup for the temporary array. +static void EmitStdInitializerListCleanup(CodeGenFunction &CGF, + QualType arrayType, + llvm::Value *addr, + const InitListExpr *initList) { + QualType::DestructionKind dtorKind = arrayType.isDestructedType(); + if (!dtorKind) + return; // Type doesn't need destroying. + if (dtorKind != QualType::DK_cxx_destructor) { + CGF.ErrorUnsupported(initList, "ObjC ARC type in initializer_list"); + return; + } + + CodeGenFunction::Destroyer *destroyer = CGF.getDestroyer(dtorKind); + CGF.pushDestroy(NormalAndEHCleanup, addr, arrayType, destroyer, + /*EHCleanup=*/true); +} + +/// \brief Emit the initializer for a std::initializer_list initialized with a +/// real initializer list. +void AggExprEmitter::EmitStdInitializerList(llvm::Value *destPtr, + InitListExpr *initList) { + // We emit an array containing the elements, then have the init list point + // at the array. + ASTContext &ctx = CGF.getContext(); + unsigned numInits = initList->getNumInits(); + QualType element = GetStdInitializerListElementType(initList->getType()); + llvm::APInt size(ctx.getTypeSize(ctx.getSizeType()), numInits); + QualType array = ctx.getConstantArrayType(element, size, ArrayType::Normal,0); + llvm::Type *LTy = CGF.ConvertTypeForMem(array); + llvm::AllocaInst *alloc = CGF.CreateTempAlloca(LTy); + alloc->setAlignment(ctx.getTypeAlignInChars(array).getQuantity()); + alloc->setName(".initlist."); + + EmitArrayInit(alloc, cast<llvm::ArrayType>(LTy), element, initList); + + // FIXME: The diagnostics are somewhat out of place here. + RecordDecl *record = initList->getType()->castAs<RecordType>()->getDecl(); + RecordDecl::field_iterator field = record->field_begin(); + if (field == record->field_end()) { + CGF.ErrorUnsupported(initList, "weird std::initializer_list"); + return; + } + + QualType elementPtr = ctx.getPointerType(element.withConst()); + + // Start pointer. + if (!ctx.hasSameType(field->getType(), elementPtr)) { + CGF.ErrorUnsupported(initList, "weird std::initializer_list"); + return; + } + LValue DestLV = CGF.MakeNaturalAlignAddrLValue(destPtr, initList->getType()); + LValue start = CGF.EmitLValueForFieldInitialization(DestLV, *field); + llvm::Value *arrayStart = Builder.CreateStructGEP(alloc, 0, "arraystart"); + CGF.EmitStoreThroughLValue(RValue::get(arrayStart), start); + ++field; + + if (field == record->field_end()) { + CGF.ErrorUnsupported(initList, "weird std::initializer_list"); + return; + } + LValue endOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *field); + if (ctx.hasSameType(field->getType(), elementPtr)) { + // End pointer. + llvm::Value *arrayEnd = Builder.CreateStructGEP(alloc,numInits, "arrayend"); + CGF.EmitStoreThroughLValue(RValue::get(arrayEnd), endOrLength); + } else if(ctx.hasSameType(field->getType(), ctx.getSizeType())) { + // Length. + CGF.EmitStoreThroughLValue(RValue::get(Builder.getInt(size)), endOrLength); + } else { + CGF.ErrorUnsupported(initList, "weird std::initializer_list"); + return; + } + + if (!Dest.isExternallyDestructed()) + EmitStdInitializerListCleanup(CGF, array, alloc, initList); +} + +/// \brief Emit initialization of an array from an initializer list. +void AggExprEmitter::EmitArrayInit(llvm::Value *DestPtr, llvm::ArrayType *AType, + QualType elementType, InitListExpr *E) { + uint64_t NumInitElements = E->getNumInits(); + + uint64_t NumArrayElements = AType->getNumElements(); + assert(NumInitElements <= NumArrayElements); + + // DestPtr is an array*. Construct an elementType* by drilling + // down a level. + llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0); + llvm::Value *indices[] = { zero, zero }; + llvm::Value *begin = + Builder.CreateInBoundsGEP(DestPtr, indices, "arrayinit.begin"); + + // Exception safety requires us to destroy all the + // already-constructed members if an initializer throws. + // For that, we'll need an EH cleanup. + QualType::DestructionKind dtorKind = elementType.isDestructedType(); + llvm::AllocaInst *endOfInit = 0; + EHScopeStack::stable_iterator cleanup; + llvm::Instruction *cleanupDominator = 0; + if (CGF.needsEHCleanup(dtorKind)) { + // In principle we could tell the cleanup where we are more + // directly, but the control flow can get so varied here that it + // would actually be quite complex. Therefore we go through an + // alloca. + endOfInit = CGF.CreateTempAlloca(begin->getType(), + "arrayinit.endOfInit"); + cleanupDominator = Builder.CreateStore(begin, endOfInit); + CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType, + CGF.getDestroyer(dtorKind)); + cleanup = CGF.EHStack.stable_begin(); + + // Otherwise, remember that we didn't need a cleanup. + } else { + dtorKind = QualType::DK_none; + } + + llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1); + + // The 'current element to initialize'. The invariants on this + // variable are complicated. Essentially, after each iteration of + // the loop, it points to the last initialized element, except + // that it points to the beginning of the array before any + // elements have been initialized. + llvm::Value *element = begin; + + // Emit the explicit initializers. + for (uint64_t i = 0; i != NumInitElements; ++i) { + // Advance to the next element. + if (i > 0) { + element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element"); + + // Tell the cleanup that it needs to destroy up to this + // element. TODO: some of these stores can be trivially + // observed to be unnecessary. + if (endOfInit) Builder.CreateStore(element, endOfInit); + } + + // If these are nested std::initializer_list inits, do them directly, + // because they are conceptually the same "location". + InitListExpr *initList = dyn_cast<InitListExpr>(E->getInit(i)); + if (initList && initList->initializesStdInitializerList()) { + EmitStdInitializerList(element, initList); + } else { + LValue elementLV = CGF.MakeAddrLValue(element, elementType); + EmitInitializationToLValue(E->getInit(i), elementLV); + } + } + + // Check whether there's a non-trivial array-fill expression. + // Note that this will be a CXXConstructExpr even if the element + // type is an array (or array of array, etc.) of class type. + Expr *filler = E->getArrayFiller(); + bool hasTrivialFiller = true; + if (CXXConstructExpr *cons = dyn_cast_or_null<CXXConstructExpr>(filler)) { + assert(cons->getConstructor()->isDefaultConstructor()); + hasTrivialFiller = cons->getConstructor()->isTrivial(); + } + + // Any remaining elements need to be zero-initialized, possibly + // using the filler expression. We can skip this if the we're + // emitting to zeroed memory. + if (NumInitElements != NumArrayElements && + !(Dest.isZeroed() && hasTrivialFiller && + CGF.getTypes().isZeroInitializable(elementType))) { + + // Use an actual loop. This is basically + // do { *array++ = filler; } while (array != end); + + // Advance to the start of the rest of the array. + if (NumInitElements) { + element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start"); + if (endOfInit) Builder.CreateStore(element, endOfInit); + } + + // Compute the end of the array. + llvm::Value *end = Builder.CreateInBoundsGEP(begin, + llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements), + "arrayinit.end"); + + llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); + llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body"); + + // Jump into the body. + CGF.EmitBlock(bodyBB); + llvm::PHINode *currentElement = + Builder.CreatePHI(element->getType(), 2, "arrayinit.cur"); + currentElement->addIncoming(element, entryBB); + + // Emit the actual filler expression. + LValue elementLV = CGF.MakeAddrLValue(currentElement, elementType); + if (filler) + EmitInitializationToLValue(filler, elementLV); + else + EmitNullInitializationToLValue(elementLV); + + // Move on to the next element. + llvm::Value *nextElement = + Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next"); + + // Tell the EH cleanup that we finished with the last element. + if (endOfInit) Builder.CreateStore(nextElement, endOfInit); + + // Leave the loop if we're done. + llvm::Value *done = Builder.CreateICmpEQ(nextElement, end, + "arrayinit.done"); + llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end"); + Builder.CreateCondBr(done, endBB, bodyBB); + currentElement->addIncoming(nextElement, Builder.GetInsertBlock()); + + CGF.EmitBlock(endBB); + } + + // Leave the partial-array cleanup if we entered one. + if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator); +} + +//===----------------------------------------------------------------------===// +// Visitor Methods +//===----------------------------------------------------------------------===// + +void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){ + Visit(E->GetTemporaryExpr()); +} + +void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) { + EmitFinalDestCopy(e, CGF.getOpaqueLValueMapping(e)); +} + +void +AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { + if (E->getType().isPODType(CGF.getContext())) { + // For a POD type, just emit a load of the lvalue + a copy, because our + // compound literal might alias the destination. + // FIXME: This is a band-aid; the real problem appears to be in our handling + // of assignments, where we store directly into the LHS without checking + // whether anything in the RHS aliases. + EmitAggLoadOfLValue(E); + return; + } + + AggValueSlot Slot = EnsureSlot(E->getType()); + CGF.EmitAggExpr(E->getInitializer(), Slot); +} + + +void AggExprEmitter::VisitCastExpr(CastExpr *E) { + switch (E->getCastKind()) { + case CK_Dynamic: { + assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?"); + LValue LV = CGF.EmitCheckedLValue(E->getSubExpr()); + // FIXME: Do we also need to handle property references here? + if (LV.isSimple()) + CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E)); + else + CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast"); + + if (!Dest.isIgnored()) + CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination"); + break; + } + + case CK_ToUnion: { + if (Dest.isIgnored()) break; + + // GCC union extension + QualType Ty = E->getSubExpr()->getType(); + QualType PtrTy = CGF.getContext().getPointerType(Ty); + llvm::Value *CastPtr = Builder.CreateBitCast(Dest.getAddr(), + CGF.ConvertType(PtrTy)); + EmitInitializationToLValue(E->getSubExpr(), + CGF.MakeAddrLValue(CastPtr, Ty)); + break; + } + + case CK_DerivedToBase: + case CK_BaseToDerived: + case CK_UncheckedDerivedToBase: { + llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: " + "should have been unpacked before we got here"); + } + + case CK_LValueToRValue: // hope for downstream optimization + case CK_NoOp: + case CK_AtomicToNonAtomic: + case CK_NonAtomicToAtomic: + case CK_UserDefinedConversion: + case CK_ConstructorConversion: + assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(), + E->getType()) && + "Implicit cast types must be compatible"); + Visit(E->getSubExpr()); + break; + + case CK_LValueBitCast: + llvm_unreachable("should not be emitting lvalue bitcast as rvalue"); + + case CK_Dependent: + case CK_BitCast: + case CK_ArrayToPointerDecay: + case CK_FunctionToPointerDecay: + case CK_NullToPointer: + case CK_NullToMemberPointer: + case CK_BaseToDerivedMemberPointer: + case CK_DerivedToBaseMemberPointer: + case CK_MemberPointerToBoolean: + case CK_ReinterpretMemberPointer: + case CK_IntegralToPointer: + case CK_PointerToIntegral: + case CK_PointerToBoolean: + case CK_ToVoid: + case CK_VectorSplat: + case CK_IntegralCast: + case CK_IntegralToBoolean: + case CK_IntegralToFloating: + case CK_FloatingToIntegral: + case CK_FloatingToBoolean: + case CK_FloatingCast: + case CK_CPointerToObjCPointerCast: + case CK_BlockPointerToObjCPointerCast: + case CK_AnyPointerToBlockPointerCast: + case CK_ObjCObjectLValueCast: + case CK_FloatingRealToComplex: + case CK_FloatingComplexToReal: + case CK_FloatingComplexToBoolean: + case CK_FloatingComplexCast: + case CK_FloatingComplexToIntegralComplex: + case CK_IntegralRealToComplex: + case CK_IntegralComplexToReal: + case CK_IntegralComplexToBoolean: + case CK_IntegralComplexCast: + case CK_IntegralComplexToFloatingComplex: + case CK_ARCProduceObject: + case CK_ARCConsumeObject: + case CK_ARCReclaimReturnedObject: + case CK_ARCExtendBlockObject: + case CK_CopyAndAutoreleaseBlockObject: + llvm_unreachable("cast kind invalid for aggregate types"); + } +} + +void AggExprEmitter::VisitCallExpr(const CallExpr *E) { + if (E->getCallReturnType()->isReferenceType()) { + EmitAggLoadOfLValue(E); + return; + } + + RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot()); + EmitMoveFromReturnSlot(E, RV); +} + +void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) { + RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot()); + EmitMoveFromReturnSlot(E, RV); +} + +void AggExprEmitter::VisitBinComma(const BinaryOperator *E) { + CGF.EmitIgnoredExpr(E->getLHS()); + Visit(E->getRHS()); +} + +void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) { + CodeGenFunction::StmtExprEvaluation eval(CGF); + CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest); +} + +void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) { + if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI) + VisitPointerToDataMemberBinaryOperator(E); + else + CGF.ErrorUnsupported(E, "aggregate binary expression"); +} + +void AggExprEmitter::VisitPointerToDataMemberBinaryOperator( + const BinaryOperator *E) { + LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E); + EmitFinalDestCopy(E, LV); +} + +void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) { + // For an assignment to work, the value on the right has + // to be compatible with the value on the left. + assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(), + E->getRHS()->getType()) + && "Invalid assignment"); + + if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E->getLHS())) + if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) + if (VD->hasAttr<BlocksAttr>() && + E->getRHS()->HasSideEffects(CGF.getContext())) { + // When __block variable on LHS, the RHS must be evaluated first + // as it may change the 'forwarding' field via call to Block_copy. + LValue RHS = CGF.EmitLValue(E->getRHS()); + LValue LHS = CGF.EmitLValue(E->getLHS()); + Dest = AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed, + needsGC(E->getLHS()->getType()), + AggValueSlot::IsAliased); + EmitFinalDestCopy(E, RHS, true); + return; + } + + LValue LHS = CGF.EmitLValue(E->getLHS()); + + // Codegen the RHS so that it stores directly into the LHS. + AggValueSlot LHSSlot = + AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed, + needsGC(E->getLHS()->getType()), + AggValueSlot::IsAliased); + CGF.EmitAggExpr(E->getRHS(), LHSSlot, false); + EmitFinalDestCopy(E, LHS, true); +} + +void AggExprEmitter:: +VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) { + llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); + llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); + llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); + + // Bind the common expression if necessary. + CodeGenFunction::OpaqueValueMapping binding(CGF, E); + + CodeGenFunction::ConditionalEvaluation eval(CGF); + CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); + + // Save whether the destination's lifetime is externally managed. + bool isExternallyDestructed = Dest.isExternallyDestructed(); + + eval.begin(CGF); + CGF.EmitBlock(LHSBlock); + Visit(E->getTrueExpr()); + eval.end(CGF); + + assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!"); + CGF.Builder.CreateBr(ContBlock); + + // If the result of an agg expression is unused, then the emission + // of the LHS might need to create a destination slot. That's fine + // with us, and we can safely emit the RHS into the same slot, but + // we shouldn't claim that it's already being destructed. + Dest.setExternallyDestructed(isExternallyDestructed); + + eval.begin(CGF); + CGF.EmitBlock(RHSBlock); + Visit(E->getFalseExpr()); + eval.end(CGF); + + CGF.EmitBlock(ContBlock); +} + +void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) { + Visit(CE->getChosenSubExpr(CGF.getContext())); +} + +void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { + llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); + llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); + + if (!ArgPtr) { + CGF.ErrorUnsupported(VE, "aggregate va_arg expression"); + return; + } + + EmitFinalDestCopy(VE, CGF.MakeAddrLValue(ArgPtr, VE->getType())); +} + +void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) { + // Ensure that we have a slot, but if we already do, remember + // whether it was externally destructed. + bool wasExternallyDestructed = Dest.isExternallyDestructed(); + Dest = EnsureSlot(E->getType()); + + // We're going to push a destructor if there isn't already one. + Dest.setExternallyDestructed(); + + Visit(E->getSubExpr()); + + // Push that destructor we promised. + if (!wasExternallyDestructed) + CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddr()); +} + +void +AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) { + AggValueSlot Slot = EnsureSlot(E->getType()); + CGF.EmitCXXConstructExpr(E, Slot); +} + +void +AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) { + AggValueSlot Slot = EnsureSlot(E->getType()); + CGF.EmitLambdaExpr(E, Slot); +} + +void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) { + CGF.enterFullExpression(E); + CodeGenFunction::RunCleanupsScope cleanups(CGF); + Visit(E->getSubExpr()); +} + +void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) { + QualType T = E->getType(); + AggValueSlot Slot = EnsureSlot(T); + EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T)); +} + +void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) { + QualType T = E->getType(); + AggValueSlot Slot = EnsureSlot(T); + EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T)); +} + +/// isSimpleZero - If emitting this value will obviously just cause a store of +/// zero to memory, return true. This can return false if uncertain, so it just +/// handles simple cases. +static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) { + E = E->IgnoreParens(); + + // 0 + if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) + return IL->getValue() == 0; + // +0.0 + if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E)) + return FL->getValue().isPosZero(); + // int() + if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) && + CGF.getTypes().isZeroInitializable(E->getType())) + return true; + // (int*)0 - Null pointer expressions. + if (const CastExpr *ICE = dyn_cast<CastExpr>(E)) + return ICE->getCastKind() == CK_NullToPointer; + // '\0' + if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) + return CL->getValue() == 0; + + // Otherwise, hard case: conservatively return false. + return false; +} + + +void +AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV) { + QualType type = LV.getType(); + // FIXME: Ignore result? + // FIXME: Are initializers affected by volatile? + if (Dest.isZeroed() && isSimpleZero(E, CGF)) { + // Storing "i32 0" to a zero'd memory location is a noop. + } else if (isa<ImplicitValueInitExpr>(E)) { + EmitNullInitializationToLValue(LV); + } else if (type->isReferenceType()) { + RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0); + CGF.EmitStoreThroughLValue(RV, LV); + } else if (type->isAnyComplexType()) { + CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false); + } else if (CGF.hasAggregateLLVMType(type)) { + CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV, + AggValueSlot::IsDestructed, + AggValueSlot::DoesNotNeedGCBarriers, + AggValueSlot::IsNotAliased, + Dest.isZeroed())); + } else if (LV.isSimple()) { + CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false); + } else { + CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV); + } +} + +void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) { + QualType type = lv.getType(); + + // If the destination slot is already zeroed out before the aggregate is + // copied into it, we don't have to emit any zeros here. + if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type)) + return; + + if (!CGF.hasAggregateLLVMType(type)) { + // For non-aggregates, we can store zero. + llvm::Value *null = llvm::Constant::getNullValue(CGF.ConvertType(type)); + // Note that the following is not equivalent to + // EmitStoreThroughBitfieldLValue for ARC types. + if (lv.isBitField()) { + CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv); + } else { + assert(lv.isSimple()); + CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true); + } + } else { + // There's a potential optimization opportunity in combining + // memsets; that would be easy for arrays, but relatively + // difficult for structures with the current code. + CGF.EmitNullInitialization(lv.getAddress(), lv.getType()); + } +} + +void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { +#if 0 + // FIXME: Assess perf here? Figure out what cases are worth optimizing here + // (Length of globals? Chunks of zeroed-out space?). + // + // If we can, prefer a copy from a global; this is a lot less code for long + // globals, and it's easier for the current optimizers to analyze. + if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) { + llvm::GlobalVariable* GV = + new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true, + llvm::GlobalValue::InternalLinkage, C, ""); + EmitFinalDestCopy(E, CGF.MakeAddrLValue(GV, E->getType())); + return; + } +#endif + if (E->hadArrayRangeDesignator()) + CGF.ErrorUnsupported(E, "GNU array range designator extension"); + + if (E->initializesStdInitializerList()) { + EmitStdInitializerList(Dest.getAddr(), E); + return; + } + + AggValueSlot Dest = EnsureSlot(E->getType()); + LValue DestLV = CGF.MakeAddrLValue(Dest.getAddr(), E->getType(), + Dest.getAlignment()); + + // Handle initialization of an array. + if (E->getType()->isArrayType()) { + if (E->isStringLiteralInit()) + return Visit(E->getInit(0)); + + QualType elementType = + CGF.getContext().getAsArrayType(E->getType())->getElementType(); + + llvm::PointerType *APType = + cast<llvm::PointerType>(Dest.getAddr()->getType()); + llvm::ArrayType *AType = + cast<llvm::ArrayType>(APType->getElementType()); + + EmitArrayInit(Dest.getAddr(), AType, elementType, E); + return; + } + + assert(E->getType()->isRecordType() && "Only support structs/unions here!"); + + // Do struct initialization; this code just sets each individual member + // to the approprate value. This makes bitfield support automatic; + // the disadvantage is that the generated code is more difficult for + // the optimizer, especially with bitfields. + unsigned NumInitElements = E->getNumInits(); + RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl(); + + if (record->isUnion()) { + // Only initialize one field of a union. The field itself is + // specified by the initializer list. + if (!E->getInitializedFieldInUnion()) { + // Empty union; we have nothing to do. + +#ifndef NDEBUG + // Make sure that it's really an empty and not a failure of + // semantic analysis. + for (RecordDecl::field_iterator Field = record->field_begin(), + FieldEnd = record->field_end(); + Field != FieldEnd; ++Field) + assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed"); +#endif + return; + } + + // FIXME: volatility + FieldDecl *Field = E->getInitializedFieldInUnion(); + + LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field); + if (NumInitElements) { + // Store the initializer into the field + EmitInitializationToLValue(E->getInit(0), FieldLoc); + } else { + // Default-initialize to null. + EmitNullInitializationToLValue(FieldLoc); + } + + return; + } + + // We'll need to enter cleanup scopes in case any of the member + // initializers throw an exception. + SmallVector<EHScopeStack::stable_iterator, 16> cleanups; + llvm::Instruction *cleanupDominator = 0; + + // Here we iterate over the fields; this makes it simpler to both + // default-initialize fields and skip over unnamed fields. + unsigned curInitIndex = 0; + for (RecordDecl::field_iterator field = record->field_begin(), + fieldEnd = record->field_end(); + field != fieldEnd; ++field) { + // We're done once we hit the flexible array member. + if (field->getType()->isIncompleteArrayType()) + break; + + // Always skip anonymous bitfields. + if (field->isUnnamedBitfield()) + continue; + + // We're done if we reach the end of the explicit initializers, we + // have a zeroed object, and the rest of the fields are + // zero-initializable. + if (curInitIndex == NumInitElements && Dest.isZeroed() && + CGF.getTypes().isZeroInitializable(E->getType())) + break; + + + LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, *field); + // We never generate write-barries for initialized fields. + LV.setNonGC(true); + + if (curInitIndex < NumInitElements) { + // Store the initializer into the field. + EmitInitializationToLValue(E->getInit(curInitIndex++), LV); + } else { + // We're out of initalizers; default-initialize to null + EmitNullInitializationToLValue(LV); + } + + // Push a destructor if necessary. + // FIXME: if we have an array of structures, all explicitly + // initialized, we can end up pushing a linear number of cleanups. + bool pushedCleanup = false; + if (QualType::DestructionKind dtorKind + = field->getType().isDestructedType()) { + assert(LV.isSimple()); + if (CGF.needsEHCleanup(dtorKind)) { + if (!cleanupDominator) + cleanupDominator = CGF.Builder.CreateUnreachable(); // placeholder + + CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(), + CGF.getDestroyer(dtorKind), false); + cleanups.push_back(CGF.EHStack.stable_begin()); + pushedCleanup = true; + } + } + + // If the GEP didn't get used because of a dead zero init or something + // else, clean it up for -O0 builds and general tidiness. + if (!pushedCleanup && LV.isSimple()) + if (llvm::GetElementPtrInst *GEP = + dyn_cast<llvm::GetElementPtrInst>(LV.getAddress())) + if (GEP->use_empty()) + GEP->eraseFromParent(); + } + + // Deactivate all the partial cleanups in reverse order, which + // generally means popping them. + for (unsigned i = cleanups.size(); i != 0; --i) + CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator); + + // Destroy the placeholder if we made one. + if (cleanupDominator) + cleanupDominator->eraseFromParent(); +} + +//===----------------------------------------------------------------------===// +// Entry Points into this File +//===----------------------------------------------------------------------===// + +/// GetNumNonZeroBytesInInit - Get an approximate count of the number of +/// non-zero bytes that will be stored when outputting the initializer for the +/// specified initializer expression. +static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) { + E = E->IgnoreParens(); + + // 0 and 0.0 won't require any non-zero stores! + if (isSimpleZero(E, CGF)) return CharUnits::Zero(); + + // If this is an initlist expr, sum up the size of sizes of the (present) + // elements. If this is something weird, assume the whole thing is non-zero. + const InitListExpr *ILE = dyn_cast<InitListExpr>(E); + if (ILE == 0 || !CGF.getTypes().isZeroInitializable(ILE->getType())) + return CGF.getContext().getTypeSizeInChars(E->getType()); + + // InitListExprs for structs have to be handled carefully. If there are + // reference members, we need to consider the size of the reference, not the + // referencee. InitListExprs for unions and arrays can't have references. + if (const RecordType *RT = E->getType()->getAs<RecordType>()) { + if (!RT->isUnionType()) { + RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl(); + CharUnits NumNonZeroBytes = CharUnits::Zero(); + + unsigned ILEElement = 0; + for (RecordDecl::field_iterator Field = SD->field_begin(), + FieldEnd = SD->field_end(); Field != FieldEnd; ++Field) { + // We're done once we hit the flexible array member or run out of + // InitListExpr elements. + if (Field->getType()->isIncompleteArrayType() || + ILEElement == ILE->getNumInits()) + break; + if (Field->isUnnamedBitfield()) + continue; + + const Expr *E = ILE->getInit(ILEElement++); + + // Reference values are always non-null and have the width of a pointer. + if (Field->getType()->isReferenceType()) + NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits( + CGF.getContext().getTargetInfo().getPointerWidth(0)); + else + NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF); + } + + return NumNonZeroBytes; + } + } + + + CharUnits NumNonZeroBytes = CharUnits::Zero(); + for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) + NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF); + return NumNonZeroBytes; +} + +/// CheckAggExprForMemSetUse - If the initializer is large and has a lot of +/// zeros in it, emit a memset and avoid storing the individual zeros. +/// +static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E, + CodeGenFunction &CGF) { + // If the slot is already known to be zeroed, nothing to do. Don't mess with + // volatile stores. + if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return; + + // C++ objects with a user-declared constructor don't need zero'ing. + if (CGF.getContext().getLangOpts().CPlusPlus) + if (const RecordType *RT = CGF.getContext() + .getBaseElementType(E->getType())->getAs<RecordType>()) { + const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); + if (RD->hasUserDeclaredConstructor()) + return; + } + + // If the type is 16-bytes or smaller, prefer individual stores over memset. + std::pair<CharUnits, CharUnits> TypeInfo = + CGF.getContext().getTypeInfoInChars(E->getType()); + if (TypeInfo.first <= CharUnits::fromQuantity(16)) + return; + + // Check to see if over 3/4 of the initializer are known to be zero. If so, + // we prefer to emit memset + individual stores for the rest. + CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF); + if (NumNonZeroBytes*4 > TypeInfo.first) + return; + + // Okay, it seems like a good idea to use an initial memset, emit the call. + llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first.getQuantity()); + CharUnits Align = TypeInfo.second; + + llvm::Value *Loc = Slot.getAddr(); + + Loc = CGF.Builder.CreateBitCast(Loc, CGF.Int8PtrTy); + CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, + Align.getQuantity(), false); + + // Tell the AggExprEmitter that the slot is known zero. + Slot.setZeroed(); +} + + + + +/// EmitAggExpr - Emit the computation of the specified expression of aggregate +/// type. The result is computed into DestPtr. Note that if DestPtr is null, +/// the value of the aggregate expression is not needed. If VolatileDest is +/// true, DestPtr cannot be 0. +/// +/// \param IsInitializer - true if this evaluation is initializing an +/// object whose lifetime is already being managed. +void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot, + bool IgnoreResult) { + assert(E && hasAggregateLLVMType(E->getType()) && + "Invalid aggregate expression to emit"); + assert((Slot.getAddr() != 0 || Slot.isIgnored()) && + "slot has bits but no address"); + + // Optimize the slot if possible. + CheckAggExprForMemSetUse(Slot, E, *this); + + AggExprEmitter(*this, Slot, IgnoreResult).Visit(const_cast<Expr*>(E)); +} + +LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) { + assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!"); + llvm::Value *Temp = CreateMemTemp(E->getType()); + LValue LV = MakeAddrLValue(Temp, E->getType()); + EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed, + AggValueSlot::DoesNotNeedGCBarriers, + AggValueSlot::IsNotAliased)); + return LV; +} + +void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr, + llvm::Value *SrcPtr, QualType Ty, + bool isVolatile, unsigned Alignment) { + assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex"); + + if (getContext().getLangOpts().CPlusPlus) { + if (const RecordType *RT = Ty->getAs<RecordType>()) { + CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl()); + assert((Record->hasTrivialCopyConstructor() || + Record->hasTrivialCopyAssignment() || + Record->hasTrivialMoveConstructor() || + Record->hasTrivialMoveAssignment()) && + "Trying to aggregate-copy a type without a trivial copy " + "constructor or assignment operator"); + // Ignore empty classes in C++. + if (Record->isEmpty()) + return; + } + } + + // Aggregate assignment turns into llvm.memcpy. This is almost valid per + // C99 6.5.16.1p3, which states "If the value being stored in an object is + // read from another object that overlaps in anyway the storage of the first + // object, then the overlap shall be exact and the two objects shall have + // qualified or unqualified versions of a compatible type." + // + // memcpy is not defined if the source and destination pointers are exactly + // equal, but other compilers do this optimization, and almost every memcpy + // implementation handles this case safely. If there is a libc that does not + // safely handle this, we can add a target hook. + + // Get size and alignment info for this aggregate. + std::pair<CharUnits, CharUnits> TypeInfo = + getContext().getTypeInfoInChars(Ty); + + if (!Alignment) + Alignment = TypeInfo.second.getQuantity(); + + // FIXME: Handle variable sized types. + + // FIXME: If we have a volatile struct, the optimizer can remove what might + // appear to be `extra' memory ops: + // + // volatile struct { int i; } a, b; + // + // int main() { + // a = b; + // a = b; + // } + // + // we need to use a different call here. We use isVolatile to indicate when + // either the source or the destination is volatile. + + llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType()); + llvm::Type *DBP = + llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace()); + DestPtr = Builder.CreateBitCast(DestPtr, DBP); + + llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType()); + llvm::Type *SBP = + llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace()); + SrcPtr = Builder.CreateBitCast(SrcPtr, SBP); + + // Don't do any of the memmove_collectable tests if GC isn't set. + if (CGM.getLangOpts().getGC() == LangOptions::NonGC) { + // fall through + } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { + RecordDecl *Record = RecordTy->getDecl(); + if (Record->hasObjectMember()) { + CharUnits size = TypeInfo.first; + llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); + llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size.getQuantity()); + CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, + SizeVal); + return; + } + } else if (Ty->isArrayType()) { + QualType BaseType = getContext().getBaseElementType(Ty); + if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) { + if (RecordTy->getDecl()->hasObjectMember()) { + CharUnits size = TypeInfo.first; + llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); + llvm::Value *SizeVal = + llvm::ConstantInt::get(SizeTy, size.getQuantity()); + CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, + SizeVal); + return; + } + } + } + + Builder.CreateMemCpy(DestPtr, SrcPtr, + llvm::ConstantInt::get(IntPtrTy, + TypeInfo.first.getQuantity()), + Alignment, isVolatile); +} + +void CodeGenFunction::MaybeEmitStdInitializerListCleanup(llvm::Value *loc, + const Expr *init) { + const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(init); + if (cleanups) + init = cleanups->getSubExpr(); + + if (isa<InitListExpr>(init) && + cast<InitListExpr>(init)->initializesStdInitializerList()) { + // We initialized this std::initializer_list with an initializer list. + // A backing array was created. Push a cleanup for it. + EmitStdInitializerListCleanup(loc, cast<InitListExpr>(init)); + } +} + +static void EmitRecursiveStdInitializerListCleanup(CodeGenFunction &CGF, + llvm::Value *arrayStart, + const InitListExpr *init) { + // Check if there are any recursive cleanups to do, i.e. if we have + // std::initializer_list<std::initializer_list<obj>> list = {{obj()}}; + // then we need to destroy the inner array as well. + for (unsigned i = 0, e = init->getNumInits(); i != e; ++i) { + const InitListExpr *subInit = dyn_cast<InitListExpr>(init->getInit(i)); + if (!subInit || !subInit->initializesStdInitializerList()) + continue; + + // This one needs to be destroyed. Get the address of the std::init_list. + llvm::Value *offset = llvm::ConstantInt::get(CGF.SizeTy, i); + llvm::Value *loc = CGF.Builder.CreateInBoundsGEP(arrayStart, offset, + "std.initlist"); + CGF.EmitStdInitializerListCleanup(loc, subInit); + } +} + +void CodeGenFunction::EmitStdInitializerListCleanup(llvm::Value *loc, + const InitListExpr *init) { + ASTContext &ctx = getContext(); + QualType element = GetStdInitializerListElementType(init->getType()); + unsigned numInits = init->getNumInits(); + llvm::APInt size(ctx.getTypeSize(ctx.getSizeType()), numInits); + QualType array =ctx.getConstantArrayType(element, size, ArrayType::Normal, 0); + QualType arrayPtr = ctx.getPointerType(array); + llvm::Type *arrayPtrType = ConvertType(arrayPtr); + + // lvalue is the location of a std::initializer_list, which as its first + // element has a pointer to the array we want to destroy. + llvm::Value *startPointer = Builder.CreateStructGEP(loc, 0, "startPointer"); + llvm::Value *startAddress = Builder.CreateLoad(startPointer, "startAddress"); + + ::EmitRecursiveStdInitializerListCleanup(*this, startAddress, init); + + llvm::Value *arrayAddress = + Builder.CreateBitCast(startAddress, arrayPtrType, "arrayAddress"); + ::EmitStdInitializerListCleanup(*this, array, arrayAddress, init); +} |