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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CGExprAgg.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CGExprAgg.cpp | 1475 |
1 files changed, 1475 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGExprAgg.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGExprAgg.cpp new file mode 100644 index 0000000..9d0f3a9 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CGExprAgg.cpp @@ -0,0 +1,1475 @@ +//===--- 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 "CGObjCRuntime.h" +#include "CodeGenModule.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/DeclTemplate.h" +#include "clang/AST/StmtVisitor.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/GlobalVariable.h" +#include "llvm/IR/Intrinsics.h" +using namespace clang; +using namespace CodeGen; + +//===----------------------------------------------------------------------===// +// Aggregate Expression Emitter +//===----------------------------------------------------------------------===// + +namespace { +class AggExprEmitter : public StmtVisitor<AggExprEmitter> { + CodeGenFunction &CGF; + CGBuilderTy &Builder; + AggValueSlot Dest; + + /// 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"); + } + void EnsureDest(QualType T) { + if (!Dest.isIgnored()) return; + Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured"); + } + +public: + AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest) + : CGF(cgf), Builder(CGF.Builder), Dest(Dest) { + } + + //===--------------------------------------------------------------------===// + // 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(QualType type, const LValue &src); + void EmitFinalDestCopy(QualType type, RValue src, + CharUnits srcAlignment = CharUnits::Zero()); + void EmitCopy(QualType type, const AggValueSlot &dest, + const AggValueSlot &src); + + void EmitMoveFromReturnSlot(const Expr *E, RValue Src); + + 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->getType(), 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 VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) { + CodeGenFunction::CXXDefaultInitExprScope Scope(CGF); + Visit(DIE->getExpr()); + } + void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E); + void VisitCXXConstructExpr(const CXXConstructExpr *E); + void VisitLambdaExpr(LambdaExpr *E); + void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *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->getType(), 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); + + // If the type of the l-value is atomic, then do an atomic load. + if (LV.getType()->isAtomicType()) { + CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest); + return; + } + + EmitFinalDestCopy(E->getType(), 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)->hasNonTrivialCopyConstructor() || + !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, copy from there to the destination. + assert(Dest.getAddr() != src.getAggregateAddr()); + std::pair<CharUnits, CharUnits> typeInfo = + CGF.getContext().getTypeInfoInChars(E->getType()); + EmitFinalDestCopy(E->getType(), src, typeInfo.second); +} + +/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. +void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src, + CharUnits srcAlign) { + assert(src.isAggregate() && "value must be aggregate value!"); + LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddr(), type, srcAlign); + EmitFinalDestCopy(type, srcLV); +} + +/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. +void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src) { + // If Dest is ignored, then we're evaluating an aggregate expression + // in a context that doesn't care about the result. Note that loads + // from volatile l-values force the existence of a non-ignored + // destination. + if (Dest.isIgnored()) + return; + + AggValueSlot srcAgg = + AggValueSlot::forLValue(src, AggValueSlot::IsDestructed, + needsGC(type), AggValueSlot::IsAliased); + EmitCopy(type, Dest, srcAgg); +} + +/// Perform a copy from the source into the destination. +/// +/// \param type - the type of the aggregate being copied; qualifiers are +/// ignored +void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest, + const AggValueSlot &src) { + if (dest.requiresGCollection()) { + CharUnits sz = CGF.getContext().getTypeSizeInChars(type); + llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity()); + CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, + dest.getAddr(), + src.getAddr(), + size); + return; + } + + // If the result of the assignment is used, copy the LHS there also. + // It's volatile if either side is. Use the minimum alignment of + // the two sides. + CGF.EmitAggregateCopy(dest.getAddr(), src.getAddr(), type, + dest.isVolatile() || src.isVolatile(), + std::min(dest.getAlignment(), src.getAlignment())); +} + +/// \brief Emit the initializer for a std::initializer_list initialized with a +/// real initializer list. +void +AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) { + // Emit an array containing the elements. The array is externally destructed + // if the std::initializer_list object is. + ASTContext &Ctx = CGF.getContext(); + LValue Array = CGF.EmitLValue(E->getSubExpr()); + assert(Array.isSimple() && "initializer_list array not a simple lvalue"); + llvm::Value *ArrayPtr = Array.getAddress(); + + const ConstantArrayType *ArrayType = + Ctx.getAsConstantArrayType(E->getSubExpr()->getType()); + assert(ArrayType && "std::initializer_list constructed from non-array"); + + // FIXME: Perform the checks on the field types in SemaInit. + RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl(); + RecordDecl::field_iterator Field = Record->field_begin(); + if (Field == Record->field_end()) { + CGF.ErrorUnsupported(E, "weird std::initializer_list"); + return; + } + + // Start pointer. + if (!Field->getType()->isPointerType() || + !Ctx.hasSameType(Field->getType()->getPointeeType(), + ArrayType->getElementType())) { + CGF.ErrorUnsupported(E, "weird std::initializer_list"); + return; + } + + AggValueSlot Dest = EnsureSlot(E->getType()); + LValue DestLV = CGF.MakeAddrLValue(Dest.getAddr(), E->getType(), + Dest.getAlignment()); + LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field); + llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0); + llvm::Value *IdxStart[] = { Zero, Zero }; + llvm::Value *ArrayStart = + Builder.CreateInBoundsGEP(ArrayPtr, IdxStart, "arraystart"); + CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start); + ++Field; + + if (Field == Record->field_end()) { + CGF.ErrorUnsupported(E, "weird std::initializer_list"); + return; + } + + llvm::Value *Size = Builder.getInt(ArrayType->getSize()); + LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field); + if (Field->getType()->isPointerType() && + Ctx.hasSameType(Field->getType()->getPointeeType(), + ArrayType->getElementType())) { + // End pointer. + llvm::Value *IdxEnd[] = { Zero, Size }; + llvm::Value *ArrayEnd = + Builder.CreateInBoundsGEP(ArrayPtr, IdxEnd, "arrayend"); + CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength); + } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) { + // Length. + CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength); + } else { + CGF.ErrorUnsupported(E, "weird std::initializer_list"); + return; + } +} + +/// \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); + } + + 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->getType(), CGF.getOpaqueLValueMapping(e)); +} + +void +AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { + if (Dest.isPotentiallyAliased() && + 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. + EmitAggLoadOfLValue(E); + return; + } + + AggValueSlot Slot = EnsureSlot(E->getType()); + CGF.EmitAggExpr(E->getInitializer(), Slot); +} + +/// Attempt to look through various unimportant expressions to find a +/// cast of the given kind. +static Expr *findPeephole(Expr *op, CastKind kind) { + while (true) { + op = op->IgnoreParens(); + if (CastExpr *castE = dyn_cast<CastExpr>(op)) { + if (castE->getCastKind() == kind) + return castE->getSubExpr(); + if (castE->getCastKind() == CK_NoOp) + continue; + } + return 0; + } +} + +void AggExprEmitter::VisitCastExpr(CastExpr *E) { + switch (E->getCastKind()) { + case CK_Dynamic: { + // FIXME: Can this actually happen? We have no test coverage for it. + assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?"); + LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(), + CodeGenFunction::TCK_Load); + // 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_NonAtomicToAtomic: + case CK_AtomicToNonAtomic: { + bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic); + + // Determine the atomic and value types. + QualType atomicType = E->getSubExpr()->getType(); + QualType valueType = E->getType(); + if (isToAtomic) std::swap(atomicType, valueType); + + assert(atomicType->isAtomicType()); + assert(CGF.getContext().hasSameUnqualifiedType(valueType, + atomicType->castAs<AtomicType>()->getValueType())); + + // Just recurse normally if we're ignoring the result or the + // atomic type doesn't change representation. + if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) { + return Visit(E->getSubExpr()); + } + + CastKind peepholeTarget = + (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic); + + // These two cases are reverses of each other; try to peephole them. + if (Expr *op = findPeephole(E->getSubExpr(), peepholeTarget)) { + assert(CGF.getContext().hasSameUnqualifiedType(op->getType(), + E->getType()) && + "peephole significantly changed types?"); + return Visit(op); + } + + // If we're converting an r-value of non-atomic type to an r-value + // of atomic type, just emit directly into the relevant sub-object. + if (isToAtomic) { + AggValueSlot valueDest = Dest; + if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) { + // Zero-initialize. (Strictly speaking, we only need to intialize + // the padding at the end, but this is simpler.) + if (!Dest.isZeroed()) + CGF.EmitNullInitialization(Dest.getAddr(), atomicType); + + // Build a GEP to refer to the subobject. + llvm::Value *valueAddr = + CGF.Builder.CreateStructGEP(valueDest.getAddr(), 0); + valueDest = AggValueSlot::forAddr(valueAddr, + valueDest.getAlignment(), + valueDest.getQualifiers(), + valueDest.isExternallyDestructed(), + valueDest.requiresGCollection(), + valueDest.isPotentiallyAliased(), + AggValueSlot::IsZeroed); + } + + CGF.EmitAggExpr(E->getSubExpr(), valueDest); + return; + } + + // Otherwise, we're converting an atomic type to a non-atomic type. + // Make an atomic temporary, emit into that, and then copy the value out. + AggValueSlot atomicSlot = + CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp"); + CGF.EmitAggExpr(E->getSubExpr(), atomicSlot); + + llvm::Value *valueAddr = + Builder.CreateStructGEP(atomicSlot.getAddr(), 0); + RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile()); + return EmitFinalDestCopy(valueType, rvalue); + } + + case CK_LValueToRValue: + // If we're loading from a volatile type, force the destination + // into existence. + if (E->getSubExpr()->getType().isVolatileQualified()) { + EnsureDest(E->getType()); + return Visit(E->getSubExpr()); + } + + // fallthrough + + case CK_NoOp: + 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: + case CK_BuiltinFnToFnPtr: + case CK_ZeroToOCLEvent: + 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->getType(), LV); +} + +/// Is the value of the given expression possibly a reference to or +/// into a __block variable? +static bool isBlockVarRef(const Expr *E) { + // Make sure we look through parens. + E = E->IgnoreParens(); + + // Check for a direct reference to a __block variable. + if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { + const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl()); + return (var && var->hasAttr<BlocksAttr>()); + } + + // More complicated stuff. + + // Binary operators. + if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) { + // For an assignment or pointer-to-member operation, just care + // about the LHS. + if (op->isAssignmentOp() || op->isPtrMemOp()) + return isBlockVarRef(op->getLHS()); + + // For a comma, just care about the RHS. + if (op->getOpcode() == BO_Comma) + return isBlockVarRef(op->getRHS()); + + // FIXME: pointer arithmetic? + return false; + + // Check both sides of a conditional operator. + } else if (const AbstractConditionalOperator *op + = dyn_cast<AbstractConditionalOperator>(E)) { + return isBlockVarRef(op->getTrueExpr()) + || isBlockVarRef(op->getFalseExpr()); + + // OVEs are required to support BinaryConditionalOperators. + } else if (const OpaqueValueExpr *op + = dyn_cast<OpaqueValueExpr>(E)) { + if (const Expr *src = op->getSourceExpr()) + return isBlockVarRef(src); + + // Casts are necessary to get things like (*(int*)&var) = foo(). + // We don't really care about the kind of cast here, except + // we don't want to look through l2r casts, because it's okay + // to get the *value* in a __block variable. + } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) { + if (cast->getCastKind() == CK_LValueToRValue) + return false; + return isBlockVarRef(cast->getSubExpr()); + + // Handle unary operators. Again, just aggressively look through + // it, ignoring the operation. + } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) { + return isBlockVarRef(uop->getSubExpr()); + + // Look into the base of a field access. + } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) { + return isBlockVarRef(mem->getBase()); + + // Look into the base of a subscript. + } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) { + return isBlockVarRef(sub->getBase()); + } + + return false; +} + +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 the LHS might be a __block variable, and the RHS can + // potentially cause a block copy, we need to evaluate the RHS first + // so that the assignment goes the right place. + // This is pretty semantically fragile. + if (isBlockVarRef(E->getLHS()) && + E->getRHS()->HasSideEffects(CGF.getContext())) { + // Ensure that we have a destination, and evaluate the RHS into that. + EnsureDest(E->getRHS()->getType()); + Visit(E->getRHS()); + + // Now emit the LHS and copy into it. + LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store); + + // That copy is an atomic copy if the LHS is atomic. + if (LHS.getType()->isAtomicType()) { + CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false); + return; + } + + EmitCopy(E->getLHS()->getType(), + AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed, + needsGC(E->getLHS()->getType()), + AggValueSlot::IsAliased), + Dest); + return; + } + + LValue LHS = CGF.EmitLValue(E->getLHS()); + + // If we have an atomic type, evaluate into the destination and then + // do an atomic copy. + if (LHS.getType()->isAtomicType()) { + EnsureDest(E->getRHS()->getType()); + Visit(E->getRHS()); + CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false); + return; + } + + // Codegen the RHS so that it stores directly into the LHS. + AggValueSlot LHSSlot = + AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed, + needsGC(E->getLHS()->getType()), + AggValueSlot::IsAliased); + // A non-volatile aggregate destination might have volatile member. + if (!LHSSlot.isVolatile() && + CGF.hasVolatileMember(E->getLHS()->getType())) + LHSSlot.setVolatile(true); + + CGF.EmitAggExpr(E->getRHS(), LHSSlot); + + // Copy into the destination if the assignment isn't ignored. + EmitFinalDestCopy(E->getType(), LHS); +} + +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()); +} + +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->getType(), 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(); + EnsureDest(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. + return; + } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) { + return EmitNullInitializationToLValue(LV); + } else if (type->isReferenceType()) { + RValue RV = CGF.EmitReferenceBindingToExpr(E); + return CGF.EmitStoreThroughLValue(RV, LV); + } + + switch (CGF.getEvaluationKind(type)) { + case TEK_Complex: + CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true); + return; + case TEK_Aggregate: + CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV, + AggValueSlot::IsDestructed, + AggValueSlot::DoesNotNeedGCBarriers, + AggValueSlot::IsNotAliased, + Dest.isZeroed())); + return; + case TEK_Scalar: + if (LV.isSimple()) { + CGF.EmitScalarInit(E, /*D=*/0, LV, /*Captured=*/false); + } else { + CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV); + } + return; + } + llvm_unreachable("bad evaluation kind"); +} + +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.hasScalarEvaluationKind(type)) { + // For non-aggregates, we can store the appropriate null constant. + llvm::Value *null = CGF.CGM.EmitNullConstant(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->getType(), CGF.MakeAddrLValue(GV, E->getType())); + return; + } +#endif + if (E->hadArrayRangeDesignator()) + CGF.ErrorUnsupported(E, "GNU array range designator extension"); + + 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(); + + // Prepare a 'this' for CXXDefaultInitExprs. + CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddr()); + + 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.getTarget().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.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. +void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) { + assert(E && hasAggregateEvaluationKind(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).Visit(const_cast<Expr*>(E)); +} + +LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) { + assert(hasAggregateEvaluationKind(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, + CharUnits alignment, + bool isAssignment) { + assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex"); + + if (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/move " + "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 data size and alignment info for this aggregate. If this is an + // assignment don't copy the tail padding. Otherwise copying it is fine. + std::pair<CharUnits, CharUnits> TypeInfo; + if (isAssignment) + TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty); + else + TypeInfo = getContext().getTypeInfoInChars(Ty); + + if (alignment.isZero()) + alignment = TypeInfo.second; + + // 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; + } + } + } + + // Determine the metadata to describe the position of any padding in this + // memcpy, as well as the TBAA tags for the members of the struct, in case + // the optimizer wishes to expand it in to scalar memory operations. + llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty); + + Builder.CreateMemCpy(DestPtr, SrcPtr, + llvm::ConstantInt::get(IntPtrTy, + TypeInfo.first.getQuantity()), + alignment.getQuantity(), isVolatile, + /*TBAATag=*/0, TBAAStructTag); +} |
