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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 | 944 |
1 files changed, 944 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..f992dc7 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CGExprAgg.cpp @@ -0,0 +1,944 @@ +//===--- 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/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; + + ReturnValueSlot getReturnValueSlot() const { + // If the destination slot requires garbage collection, we can't + // use the real return value slot, because we have to use the GC + // API. + if (Dest.requiresGCollection()) 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); + + void EmitGCMove(const Expr *E, RValue Src); + + bool TypeRequiresGCollection(QualType T); + + //===--------------------------------------------------------------------===// + // Visitor Methods + //===--------------------------------------------------------------------===// + + void VisitStmt(Stmt *S) { + CGF.ErrorUnsupported(S, "aggregate expression"); + } + void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); } + void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); } + + // l-values. + void VisitDeclRefExpr(DeclRefExpr *DRE) { EmitAggLoadOfLValue(DRE); } + void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); } + void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); } + void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); } + void VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { + EmitAggLoadOfLValue(E); + } + void VisitArraySubscriptExpr(ArraySubscriptExpr *E) { + EmitAggLoadOfLValue(E); + } + void VisitBlockDeclRefExpr(const BlockDeclRefExpr *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 VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *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 VisitExprWithCleanups(ExprWithCleanups *E); + void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E); + void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); } + + void VisitOpaqueValueExpr(OpaqueValueExpr *E); + + void VisitVAArgExpr(VAArgExpr *E); + + void EmitInitializationToLValue(Expr *E, LValue Address, QualType T); + void EmitNullInitializationToLValue(LValue Address, QualType T); + // case Expr::ChooseExprClass: + void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); } +}; +} // 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 RequiresGCollection is set. +/// +/// The idea is that you do something like this: +/// RValue Result = EmitSomething(..., getReturnValueSlot()); +/// EmitGCMove(E, Result); +/// If GC doesn't interfere, this will cause the result to be emitted +/// directly into the return value slot. If GC does interfere, a final +/// move will be performed. +void AggExprEmitter::EmitGCMove(const Expr *E, RValue Src) { + if (Dest.requiresGCollection()) { + std::pair<uint64_t, unsigned> TypeInfo = + CGF.getContext().getTypeInfo(E->getType()); + unsigned long size = TypeInfo.first/8; + const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType()); + llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); + CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, Dest.getAddr(), + Src.getAggregateAddr(), + SizeVal); + } +} + +/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. +void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) { + 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.getLangOptions().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()) { + std::pair<uint64_t, unsigned> TypeInfo = + CGF.getContext().getTypeInfo(E->getType()); + unsigned long size = TypeInfo.first/8; + const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType()); + llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); + 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()); +} + +/// 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"); + + EmitFinalDestCopy(E, RValue::getAggregate(Src.getAddress(), + Src.isVolatileQualified()), + Ignore); +} + +//===----------------------------------------------------------------------===// +// Visitor Methods +//===----------------------------------------------------------------------===// + +void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) { + EmitFinalDestCopy(e, CGF.getOpaqueLValueMapping(e)); +} + +void AggExprEmitter::VisitCastExpr(CastExpr *E) { + if (Dest.isIgnored() && E->getCastKind() != CK_Dynamic) { + Visit(E->getSubExpr()); + return; + } + + 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: { + // 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), + Ty); + break; + } + + case CK_DerivedToBase: + case CK_BaseToDerived: + case CK_UncheckedDerivedToBase: { + assert(0 && "cannot perform hierarchy conversion in EmitAggExpr: " + "should have been unpacked before we got here"); + break; + } + + case CK_GetObjCProperty: { + LValue LV = CGF.EmitLValue(E->getSubExpr()); + assert(LV.isPropertyRef()); + RValue RV = CGF.EmitLoadOfPropertyRefLValue(LV, getReturnValueSlot()); + EmitGCMove(E, RV); + break; + } + + case CK_LValueToRValue: // hope for downstream optimization + 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"); + break; + + 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_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_AnyPointerToObjCPointerCast: + 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: + 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()); + EmitGCMove(E, RV); +} + +void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) { + RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot()); + EmitGCMove(E, RV); +} + +void AggExprEmitter::VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) { + llvm_unreachable("direct property access not surrounded by " + "lvalue-to-rvalue cast"); +} + +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"); + + // FIXME: __block variables need the RHS evaluated first! + LValue LHS = CGF.EmitLValue(E->getLHS()); + + // We have to special case property setters, otherwise we must have + // a simple lvalue (no aggregates inside vectors, bitfields). + if (LHS.isPropertyRef()) { + AggValueSlot Slot = EnsureSlot(E->getRHS()->getType()); + CGF.EmitAggExpr(E->getRHS(), Slot); + CGF.EmitStoreThroughPropertyRefLValue(Slot.asRValue(), LHS); + } else { + bool GCollection = false; + if (CGF.getContext().getLangOptions().getGCMode()) + GCollection = TypeRequiresGCollection(E->getLHS()->getType()); + + // Codegen the RHS so that it stores directly into the LHS. + AggValueSlot LHSSlot = AggValueSlot::forLValue(LHS, true, + GCollection); + 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 DestLifetimeManaged = Dest.isLifetimeExternallyManaged(); + + 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 its lifetime is externally managed. + Dest.setLifetimeExternallyManaged(DestLifetimeManaged); + + 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 its lifetime was externally managed. + bool WasManaged = Dest.isLifetimeExternallyManaged(); + Dest = EnsureSlot(E->getType()); + Dest.setLifetimeExternallyManaged(); + + Visit(E->getSubExpr()); + + // Set up the temporary's destructor if its lifetime wasn't already + // being managed. + if (!WasManaged) + CGF.EmitCXXTemporary(E->getTemporary(), Dest.getAddr()); +} + +void +AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) { + AggValueSlot Slot = EnsureSlot(E->getType()); + CGF.EmitCXXConstructExpr(E, Slot); +} + +void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) { + CGF.EmitExprWithCleanups(E, Dest); +} + +void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) { + QualType T = E->getType(); + AggValueSlot Slot = EnsureSlot(T); + EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T), T); +} + +void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) { + QualType T = E->getType(); + AggValueSlot Slot = EnsureSlot(T); + EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T), 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) { + // (0) + if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) + return isSimpleZero(PE->getSubExpr(), CGF); + // 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 T) { + // 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, T); + } else if (T->isReferenceType()) { + RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0); + CGF.EmitStoreThroughLValue(RV, LV, T); + } else if (T->isAnyComplexType()) { + CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false); + } else if (CGF.hasAggregateLLVMType(T)) { + CGF.EmitAggExpr(E, AggValueSlot::forAddr(LV.getAddress(), false, true, + false, Dest.isZeroed())); + } else { + CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV, T); + } +} + +void AggExprEmitter::EmitNullInitializationToLValue(LValue LV, QualType T) { + // 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(T)) + return; + + if (!CGF.hasAggregateLLVMType(T)) { + // For non-aggregates, we can store zero + llvm::Value *Null = llvm::Constant::getNullValue(CGF.ConvertType(T)); + CGF.EmitStoreThroughLValue(RValue::get(Null), LV, T); + } 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(), T); + } +} + +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"); + + llvm::Value *DestPtr = Dest.getAddr(); + + // Handle initialization of an array. + if (E->getType()->isArrayType()) { + const llvm::PointerType *APType = + cast<llvm::PointerType>(DestPtr->getType()); + const llvm::ArrayType *AType = + cast<llvm::ArrayType>(APType->getElementType()); + + uint64_t NumInitElements = E->getNumInits(); + + if (E->getNumInits() > 0) { + QualType T1 = E->getType(); + QualType T2 = E->getInit(0)->getType(); + if (CGF.getContext().hasSameUnqualifiedType(T1, T2)) { + EmitAggLoadOfLValue(E->getInit(0)); + return; + } + } + + uint64_t NumArrayElements = AType->getNumElements(); + QualType ElementType = CGF.getContext().getCanonicalType(E->getType()); + ElementType = CGF.getContext().getAsArrayType(ElementType)->getElementType(); + + // FIXME: were we intentionally ignoring address spaces and GC attributes? + + for (uint64_t i = 0; i != NumArrayElements; ++i) { + // If we're done emitting initializers and the destination is known-zeroed + // then we're done. + if (i == NumInitElements && + Dest.isZeroed() && + CGF.getTypes().isZeroInitializable(ElementType)) + break; + + llvm::Value *NextVal = Builder.CreateStructGEP(DestPtr, i, ".array"); + LValue LV = CGF.MakeAddrLValue(NextVal, ElementType); + + if (i < NumInitElements) + EmitInitializationToLValue(E->getInit(i), LV, ElementType); + else + EmitNullInitializationToLValue(LV, ElementType); + + // 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 (llvm::GetElementPtrInst *GEP = + dyn_cast<llvm::GetElementPtrInst>(NextVal)) + if (GEP->use_empty()) + GEP->eraseFromParent(); + } + 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 *SD = E->getType()->getAs<RecordType>()->getDecl(); + + if (E->getType()->isUnionType()) { + // 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 = SD->field_begin(), + FieldEnd = SD->field_end(); + Field != FieldEnd; ++Field) + assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed"); +#endif + return; + } + + // FIXME: volatility + FieldDecl *Field = E->getInitializedFieldInUnion(); + + LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0); + if (NumInitElements) { + // Store the initializer into the field + EmitInitializationToLValue(E->getInit(0), FieldLoc, Field->getType()); + } else { + // Default-initialize to null. + EmitNullInitializationToLValue(FieldLoc, Field->getType()); + } + + return; + } + + // Here we iterate over the fields; this makes it simpler to both + // default-initialize fields and skip over unnamed fields. + unsigned CurInitVal = 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 + if (Field->getType()->isIncompleteArrayType()) + break; + + if (Field->isUnnamedBitfield()) + continue; + + // Don't emit GEP before a noop store of zero. + if (CurInitVal == NumInitElements && Dest.isZeroed() && + CGF.getTypes().isZeroInitializable(E->getType())) + break; + + // FIXME: volatility + LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, *Field, 0); + // We never generate write-barries for initialized fields. + FieldLoc.setNonGC(true); + + if (CurInitVal < NumInitElements) { + // Store the initializer into the field. + EmitInitializationToLValue(E->getInit(CurInitVal++), FieldLoc, + Field->getType()); + } else { + // We're out of initalizers; default-initialize to null + EmitNullInitializationToLValue(FieldLoc, Field->getType()); + } + + // 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 (FieldLoc.isSimple()) + if (llvm::GetElementPtrInst *GEP = + dyn_cast<llvm::GetElementPtrInst>(FieldLoc.getAddress())) + if (GEP->use_empty()) + GEP->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 uint64_t GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) { + if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) + return GetNumNonZeroBytesInInit(PE->getSubExpr(), CGF); + + // 0 and 0.0 won't require any non-zero stores! + if (isSimpleZero(E, CGF)) return 0; + + // 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().getTypeSize(E->getType())/8; + + // 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(); + uint64_t NumNonZeroBytes = 0; + + 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().Target.getPointerWidth(0); + else + NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF); + } + + return NumNonZeroBytes; + } + } + + + uint64_t NumNonZeroBytes = 0; + 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; + + // If the type is 16-bytes or smaller, prefer individual stores over memset. + std::pair<uint64_t, unsigned> TypeInfo = + CGF.getContext().getTypeInfo(E->getType()); + if (TypeInfo.first/8 <= 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. + uint64_t NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF); + if (NumNonZeroBytes*4 > TypeInfo.first/8) + return; + + // Okay, it seems like a good idea to use an initial memset, emit the call. + llvm::Constant *SizeVal = CGF.Builder.getInt64(TypeInfo.first/8); + unsigned Align = TypeInfo.second/8; + + llvm::Value *Loc = Slot.getAddr(); + const llvm::Type *BP = llvm::Type::getInt8PtrTy(CGF.getLLVMContext()); + + Loc = CGF.Builder.CreateBitCast(Loc, BP); + CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, Align, 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. +// +// FIXME: Take Qualifiers object. +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::forAddr(Temp, LV.isVolatileQualified(), false)); + return LV; +} + +void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr, + llvm::Value *SrcPtr, QualType Ty, + bool isVolatile) { + assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex"); + + if (getContext().getLangOptions().CPlusPlus) { + if (const RecordType *RT = Ty->getAs<RecordType>()) { + CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl()); + assert((Record->hasTrivialCopyConstructor() || + Record->hasTrivialCopyAssignment()) && + "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<uint64_t, unsigned> TypeInfo = getContext().getTypeInfo(Ty); + + // 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. + + const llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType()); + const llvm::Type *DBP = + llvm::Type::getInt8PtrTy(getLLVMContext(), DPT->getAddressSpace()); + DestPtr = Builder.CreateBitCast(DestPtr, DBP, "tmp"); + + const llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType()); + const llvm::Type *SBP = + llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace()); + SrcPtr = Builder.CreateBitCast(SrcPtr, SBP, "tmp"); + + if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { + RecordDecl *Record = RecordTy->getDecl(); + if (Record->hasObjectMember()) { + unsigned long size = TypeInfo.first/8; + const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); + llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); + CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, + SizeVal); + return; + } + } else if (getContext().getAsArrayType(Ty)) { + QualType BaseType = getContext().getBaseElementType(Ty); + if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) { + if (RecordTy->getDecl()->hasObjectMember()) { + unsigned long size = TypeInfo.first/8; + const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); + llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); + CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, + SizeVal); + return; + } + } + } + + Builder.CreateMemCpy(DestPtr, SrcPtr, + llvm::ConstantInt::get(IntPtrTy, TypeInfo.first/8), + TypeInfo.second/8, isVolatile); +} |
