diff options
Diffstat (limited to 'lib/CodeGen/CGExprAgg.cpp')
| -rw-r--r-- | lib/CodeGen/CGExprAgg.cpp | 480 |
1 files changed, 324 insertions, 156 deletions
diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp index 28c8b3545b38..f992dc7c9cb9 100644 --- a/lib/CodeGen/CGExprAgg.cpp +++ b/lib/CodeGen/CGExprAgg.cpp @@ -32,27 +32,28 @@ namespace { class AggExprEmitter : public StmtVisitor<AggExprEmitter> { CodeGenFunction &CGF; CGBuilderTy &Builder; - llvm::Value *DestPtr; - bool VolatileDest; + AggValueSlot Dest; bool IgnoreResult; - bool IsInitializer; - bool RequiresGCollection; 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 (RequiresGCollection) return ReturnValueSlot(); + if (Dest.requiresGCollection()) return ReturnValueSlot(); - return ReturnValueSlot(DestPtr, VolatileDest); + 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, llvm::Value *destPtr, bool v, - bool ignore, bool isinit, bool requiresGCollection) - : CGF(cgf), Builder(CGF.Builder), - DestPtr(destPtr), VolatileDest(v), IgnoreResult(ignore), - IsInitializer(isinit), RequiresGCollection(requiresGCollection) { + AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, + bool ignore) + : CGF(cgf), Builder(CGF.Builder), Dest(Dest), + IgnoreResult(ignore) { } //===--------------------------------------------------------------------===// @@ -114,9 +115,8 @@ public: EmitAggLoadOfLValue(E); } void VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E); - void VisitObjCImplicitSetterGetterRefExpr(ObjCImplicitSetterGetterRefExpr *E); - void VisitConditionalOperator(const ConditionalOperator *CO); + void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO); void VisitChooseExpr(const ChooseExpr *CE); void VisitInitListExpr(InitListExpr *E); void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E); @@ -125,10 +125,12 @@ public: } void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E); void VisitCXXConstructExpr(const CXXConstructExpr *E); - void VisitCXXExprWithTemporaries(CXXExprWithTemporaries *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); @@ -176,13 +178,13 @@ bool AggExprEmitter::TypeRequiresGCollection(QualType T) { /// 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 (RequiresGCollection) { + 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, DestPtr, + CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, Dest.getAddr(), Src.getAggregateAddr(), SizeVal); } @@ -192,13 +194,13 @@ void AggExprEmitter::EmitGCMove(const Expr *E, RValue Src) { void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) { assert(Src.isAggregate() && "value must be aggregate value!"); - // If DestPtr is null, then we're evaluating an aggregate expression + // 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 (DestPtr == 0) { + if (Dest.isIgnored()) { if (!Src.isVolatileQualified() || CGF.CGM.getLangOptions().CPlusPlus || (IgnoreResult && Ignore)) @@ -206,26 +208,27 @@ void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) { // If the source is volatile, we must read from it; to do that, we need // some place to put it. - DestPtr = CGF.CreateMemTemp(E->getType(), "agg.tmp"); + Dest = CGF.CreateAggTemp(E->getType(), "agg.tmp"); } - if (RequiresGCollection) { + 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, - DestPtr, Src.getAggregateAddr(), - SizeVal); + 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(DestPtr, Src.getAggregateAddr(), E->getType(), - VolatileDest|Src.isVolatileQualified()); + CGF.EmitAggregateCopy(Dest.getAddr(), Src.getAggregateAddr(), E->getType(), + Dest.isVolatile()|Src.isVolatileQualified()); } /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. @@ -241,15 +244,17 @@ void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) { // Visitor Methods //===----------------------------------------------------------------------===// +void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) { + EmitFinalDestCopy(e, CGF.getOpaqueLValueMapping(e)); +} + void AggExprEmitter::VisitCastExpr(CastExpr *E) { - if (!DestPtr && E->getCastKind() != CK_Dynamic) { + if (Dest.isIgnored() && E->getCastKind() != CK_Dynamic) { Visit(E->getSubExpr()); return; } switch (E->getCastKind()) { - default: assert(0 && "Unhandled cast kind!"); - case CK_Dynamic: { assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?"); LValue LV = CGF.EmitCheckedLValue(E->getSubExpr()); @@ -259,8 +264,8 @@ void AggExprEmitter::VisitCastExpr(CastExpr *E) { else CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast"); - if (DestPtr) - CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination"); + if (!Dest.isIgnored()) + CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination"); break; } @@ -268,7 +273,7 @@ void AggExprEmitter::VisitCastExpr(CastExpr *E) { // GCC union extension QualType Ty = E->getSubExpr()->getType(); QualType PtrTy = CGF.getContext().getPointerType(Ty); - llvm::Value *CastPtr = Builder.CreateBitCast(DestPtr, + llvm::Value *CastPtr = Builder.CreateBitCast(Dest.getAddr(), CGF.ConvertType(PtrTy)); EmitInitializationToLValue(E->getSubExpr(), CGF.MakeAddrLValue(CastPtr, Ty), Ty); @@ -283,8 +288,15 @@ void AggExprEmitter::VisitCastExpr(CastExpr *E) { break; } - // FIXME: Remove the CK_Unknown check here. - case CK_Unknown: + 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: @@ -293,10 +305,45 @@ void AggExprEmitter::VisitCastExpr(CastExpr *E) { "Implicit cast types must be compatible"); Visit(E->getSubExpr()); break; - + case CK_LValueBitCast: - llvm_unreachable("there are no lvalue bit-casts on aggregates"); + 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"); } } @@ -316,24 +363,18 @@ void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) { } void AggExprEmitter::VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) { - RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot()); - EmitGCMove(E, RV); -} - -void AggExprEmitter::VisitObjCImplicitSetterGetterRefExpr( - ObjCImplicitSetterGetterRefExpr *E) { - RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot()); - EmitGCMove(E, RV); + llvm_unreachable("direct property access not surrounded by " + "lvalue-to-rvalue cast"); } void AggExprEmitter::VisitBinComma(const BinaryOperator *E) { - CGF.EmitAnyExpr(E->getLHS(), 0, false, true); - CGF.EmitAggExpr(E->getRHS(), DestPtr, VolatileDest, - /*IgnoreResult=*/false, IsInitializer); + CGF.EmitIgnoredExpr(E->getLHS()); + Visit(E->getRHS()); } void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) { - CGF.EmitCompoundStmt(*E->getSubStmt(), true, DestPtr, VolatileDest); + CodeGenFunction::StmtExprEvaluation eval(CGF); + CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest); } void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) { @@ -355,64 +396,62 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) { 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()) { - llvm::Value *AggLoc = DestPtr; - if (!AggLoc) - AggLoc = CGF.CreateMemTemp(E->getRHS()->getType()); - CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest); - CGF.EmitObjCPropertySet(LHS.getPropertyRefExpr(), - RValue::getAggregate(AggLoc, VolatileDest)); - } else if (LHS.isKVCRef()) { - llvm::Value *AggLoc = DestPtr; - if (!AggLoc) - AggLoc = CGF.CreateMemTemp(E->getRHS()->getType()); - CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest); - CGF.EmitObjCPropertySet(LHS.getKVCRefExpr(), - RValue::getAggregate(AggLoc, VolatileDest)); + AggValueSlot Slot = EnsureSlot(E->getRHS()->getType()); + CGF.EmitAggExpr(E->getRHS(), Slot); + CGF.EmitStoreThroughPropertyRefLValue(Slot.asRValue(), LHS); } else { - bool RequiresGCollection = false; + bool GCollection = false; if (CGF.getContext().getLangOptions().getGCMode()) - RequiresGCollection = TypeRequiresGCollection(E->getLHS()->getType()); + GCollection = TypeRequiresGCollection(E->getLHS()->getType()); // Codegen the RHS so that it stores directly into the LHS. - CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), LHS.isVolatileQualified(), - false, false, RequiresGCollection); + AggValueSlot LHSSlot = AggValueSlot::forLValue(LHS, true, + GCollection); + CGF.EmitAggExpr(E->getRHS(), LHSSlot, false); EmitFinalDestCopy(E, LHS, true); } } -void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) { - if (!E->getLHS()) { - CGF.ErrorUnsupported(E, "conditional operator with missing LHS"); - return; - } - +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); - CGF.BeginConditionalBranch(); + // 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); - // Handle the GNU extension for missing LHS. - assert(E->getLHS() && "Must have LHS for aggregate value"); + assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!"); + CGF.Builder.CreateBr(ContBlock); - Visit(E->getLHS()); - CGF.EndConditionalBranch(); - CGF.EmitBranch(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); - CGF.BeginConditionalBranch(); + eval.begin(CGF); CGF.EmitBlock(RHSBlock); - - Visit(E->getRHS()); - CGF.EndConditionalBranch(); - CGF.EmitBranch(ContBlock); + Visit(E->getFalseExpr()); + eval.end(CGF); CGF.EmitBlock(ContBlock); } @@ -434,65 +473,78 @@ void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { } void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) { - llvm::Value *Val = DestPtr; - - if (!Val) { - // Create a temporary variable. - Val = CGF.CreateMemTemp(E->getType(), "tmp"); - - // FIXME: volatile - CGF.EmitAggExpr(E->getSubExpr(), Val, false); - } else - Visit(E->getSubExpr()); - - // Don't make this a live temporary if we're emitting an initializer expr. - if (!IsInitializer) - CGF.EmitCXXTemporary(E->getTemporary(), Val); + // 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) { - llvm::Value *Val = DestPtr; - - if (!Val) // Create a temporary variable. - Val = CGF.CreateMemTemp(E->getType(), "tmp"); - - CGF.EmitCXXConstructExpr(Val, E); + AggValueSlot Slot = EnsureSlot(E->getType()); + CGF.EmitCXXConstructExpr(E, Slot); } -void AggExprEmitter::VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E) { - llvm::Value *Val = DestPtr; - - CGF.EmitCXXExprWithTemporaries(E, Val, VolatileDest, IsInitializer); +void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) { + CGF.EmitExprWithCleanups(E, Dest); } void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) { - llvm::Value *Val = DestPtr; - - if (!Val) { - // Create a temporary variable. - Val = CGF.CreateMemTemp(E->getType(), "tmp"); - } - EmitNullInitializationToLValue(CGF.MakeAddrLValue(Val, E->getType()), - E->getType()); + QualType T = E->getType(); + AggValueSlot Slot = EnsureSlot(T); + EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T), T); } void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) { - llvm::Value *Val = DestPtr; + QualType T = E->getType(); + AggValueSlot Slot = EnsureSlot(T); + EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddr(), T), T); +} - if (!Val) { - // Create a temporary variable. - Val = CGF.CreateMemTemp(E->getType(), "tmp"); - } - EmitNullInitializationToLValue(CGF.MakeAddrLValue(Val, E->getType()), - E->getType()); +/// 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 (isa<ImplicitValueInitExpr>(E)) { + 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); @@ -500,13 +552,19 @@ AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV, QualType T) { } else if (T->isAnyComplexType()) { CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false); } else if (CGF.hasAggregateLLVMType(T)) { - CGF.EmitAnyExpr(E, LV.getAddress(), false); + CGF.EmitAggExpr(E, AggValueSlot::forAddr(LV.getAddress(), false, true, + false, Dest.isZeroed())); } else { - CGF.EmitStoreThroughLValue(CGF.EmitAnyExpr(E), LV, T); + 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)); @@ -534,9 +592,10 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { return; } #endif - if (E->hadArrayRangeDesignator()) { + 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()) { @@ -563,13 +622,27 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { // 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; } @@ -583,16 +656,6 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { unsigned NumInitElements = E->getNumInits(); RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl(); - // If we're initializing the whole aggregate, just do it in place. - // FIXME: This is a hack around an AST bug (PR6537). - if (NumInitElements == 1 && E->getType() == E->getInit(0)->getType()) { - EmitInitializationToLValue(E->getInit(0), - CGF.MakeAddrLValue(DestPtr, E->getType()), - E->getType()); - return; - } - - if (E->getType()->isUnionType()) { // Only initialize one field of a union. The field itself is // specified by the initializer list. @@ -612,13 +675,13 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { // FIXME: volatility FieldDecl *Field = E->getInitializedFieldInUnion(); - LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0); + 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 + // Default-initialize to null. EmitNullInitializationToLValue(FieldLoc, Field->getType()); } @@ -638,10 +701,16 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { 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, @@ -650,6 +719,14 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { // 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(); } } @@ -657,31 +734,126 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { // 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, llvm::Value *DestPtr, - bool VolatileDest, bool IgnoreResult, - bool IsInitializer, - bool RequiresGCollection) { +void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot, + bool IgnoreResult) { assert(E && hasAggregateLLVMType(E->getType()) && "Invalid aggregate expression to emit"); - assert ((DestPtr != 0 || VolatileDest == false) - && "volatile aggregate can't be 0"); + assert((Slot.getAddr() != 0 || Slot.isIgnored()) && + "slot has bits but no address"); - AggExprEmitter(*this, DestPtr, VolatileDest, IgnoreResult, IsInitializer, - RequiresGCollection) - .Visit(const_cast<Expr*>(E)); + // 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, Temp, LV.isVolatileQualified()); + EmitAggExpr(E, AggValueSlot::forAddr(Temp, LV.isVolatileQualified(), false)); return LV; } @@ -734,12 +906,12 @@ void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr, const llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType()); const llvm::Type *DBP = - llvm::Type::getInt8PtrTy(VMContext, DPT->getAddressSpace()); + 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(VMContext, SPT->getAddressSpace()); + llvm::Type::getInt8PtrTy(getLLVMContext(), SPT->getAddressSpace()); SrcPtr = Builder.CreateBitCast(SrcPtr, SBP, "tmp"); if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { @@ -766,11 +938,7 @@ void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr, } } - Builder.CreateCall5(CGM.getMemCpyFn(DestPtr->getType(), SrcPtr->getType(), - IntPtrTy), - DestPtr, SrcPtr, - // TypeInfo.first describes size in bits. - llvm::ConstantInt::get(IntPtrTy, TypeInfo.first/8), - Builder.getInt32(TypeInfo.second/8), - Builder.getInt1(isVolatile)); + Builder.CreateMemCpy(DestPtr, SrcPtr, + llvm::ConstantInt::get(IntPtrTy, TypeInfo.first/8), + TypeInfo.second/8, isVolatile); } |