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CGExprAgg.cpp
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//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Aggregate Expr nodes as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CGCXXABI.h"
#include "CGObjCRuntime.h"
#include "CGRecordLayout.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
#include "EHScopeStack.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.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/Instruction.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
using namespace clang;
using namespace CodeGen;
//===----------------------------------------------------------------------===//
// Aggregate Expression Emitter
//===----------------------------------------------------------------------===//
namespace llvm {
extern cl::opt<bool> EnableSingleByteCoverage;
} // namespace llvm
namespace {
class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
CodeGenFunction &CGF;
CGBuilderTy &Builder;
AggValueSlot Dest;
bool IsResultUnused;
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");
}
// Calls `Fn` with a valid return value slot, potentially creating a temporary
// to do so. If a temporary is created, an appropriate copy into `Dest` will
// be emitted, as will lifetime markers.
//
// The given function should take a ReturnValueSlot, and return an RValue that
// points to said slot.
void withReturnValueSlot(const Expr *E,
llvm::function_ref<RValue(ReturnValueSlot)> Fn);
void DoZeroInitPadding(uint64_t &PaddingStart, uint64_t PaddingEnd,
const FieldDecl *NextField);
public:
AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused)
: CGF(cgf), Builder(CGF.Builder), Dest(Dest),
IsResultUnused(IsResultUnused) { }
//===--------------------------------------------------------------------===//
// 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.
/// SrcIsRValue is true if source comes from an RValue.
void EmitFinalDestCopy(QualType type, const LValue &src,
CodeGenFunction::ExprValueKind SrcValueKind =
CodeGenFunction::EVK_NonRValue);
void EmitFinalDestCopy(QualType type, RValue src);
void EmitCopy(QualType type, const AggValueSlot &dest,
const AggValueSlot &src);
void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType, QualType ArrayQTy,
Expr *ExprToVisit, ArrayRef<Expr *> Args,
Expr *ArrayFiller);
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 Visit(Expr *E) {
ApplyDebugLocation DL(CGF, E);
StmtVisitor<AggExprEmitter>::Visit(E);
}
void VisitStmt(Stmt *S) {
CGF.ErrorUnsupported(S, "aggregate expression");
}
void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
Visit(GE->getResultExpr());
}
void VisitCoawaitExpr(CoawaitExpr *E) {
CGF.EmitCoawaitExpr(*E, Dest, IsResultUnused);
}
void VisitCoyieldExpr(CoyieldExpr *E) {
CGF.EmitCoyieldExpr(*E, Dest, IsResultUnused);
}
void VisitUnaryCoawait(UnaryOperator *E) { Visit(E->getSubExpr()); }
void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
return Visit(E->getReplacement());
}
void VisitConstantExpr(ConstantExpr *E) {
EnsureDest(E->getType());
if (llvm::Value *Result = ConstantEmitter(CGF).tryEmitConstantExpr(E)) {
CGF.CreateCoercedStore(
Result, Dest.getAddress(),
llvm::TypeSize::getFixed(
Dest.getPreferredSize(CGF.getContext(), E->getType())
.getQuantity()),
E->getType().isVolatileQualified());
return;
}
return Visit(E->getSubExpr());
}
// l-values.
void VisitDeclRefExpr(DeclRefExpr *E) { 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 VisitBinCmp(const BinaryOperator *E);
void VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) {
Visit(E->getSemanticForm());
}
void VisitObjCMessageExpr(ObjCMessageExpr *E);
void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
EmitAggLoadOfLValue(E);
}
void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E);
void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
void VisitChooseExpr(const ChooseExpr *CE);
void VisitInitListExpr(InitListExpr *E);
void VisitCXXParenListOrInitListExpr(Expr *ExprToVisit, ArrayRef<Expr *> Args,
FieldDecl *InitializedFieldInUnion,
Expr *ArrayFiller);
void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
llvm::Value *outerBegin = nullptr);
void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing.
void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE);
Visit(DAE->getExpr());
}
void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE);
Visit(DIE->getExpr());
}
void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
void VisitCXXConstructExpr(const CXXConstructExpr *E);
void VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *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);
}
AggValueSlot Slot = EnsureSlot(E->getType());
bool NeedsDestruction =
!Slot.isExternallyDestructed() &&
E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct;
if (NeedsDestruction)
Slot.setExternallyDestructed();
CGF.EmitPseudoObjectRValue(E, Slot);
if (NeedsDestruction)
CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Slot.getAddress(),
E->getType());
}
void VisitVAArgExpr(VAArgExpr *E);
void VisitCXXParenListInitExpr(CXXParenListInitExpr *E);
void VisitCXXParenListOrInitListExpr(Expr *ExprToVisit, ArrayRef<Expr *> Args,
Expr *ArrayFiller);
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) {
RValue Res = CGF.EmitAtomicExpr(E);
EmitFinalDestCopy(E->getType(), Res);
}
void VisitPackIndexingExpr(PackIndexingExpr *E) {
Visit(E->getSelectedExpr());
}
};
} // 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.LValueIsSuitableForInlineAtomic(LV)) {
CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
return;
}
EmitFinalDestCopy(E->getType(), LV);
}
/// 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();
}
void AggExprEmitter::withReturnValueSlot(
const Expr *E, llvm::function_ref<RValue(ReturnValueSlot)> EmitCall) {
QualType RetTy = E->getType();
bool RequiresDestruction =
!Dest.isExternallyDestructed() &&
RetTy.isDestructedType() == QualType::DK_nontrivial_c_struct;
// If it makes no observable difference, save a memcpy + temporary.
//
// We need to always provide our own temporary if destruction is required.
// Otherwise, EmitCall will emit its own, notice that it's "unused", and end
// its lifetime before we have the chance to emit a proper destructor call.
bool UseTemp = Dest.isPotentiallyAliased() || Dest.requiresGCollection() ||
(RequiresDestruction && Dest.isIgnored());
Address RetAddr = Address::invalid();
RawAddress RetAllocaAddr = RawAddress::invalid();
EHScopeStack::stable_iterator LifetimeEndBlock;
llvm::Value *LifetimeSizePtr = nullptr;
llvm::IntrinsicInst *LifetimeStartInst = nullptr;
if (!UseTemp) {
RetAddr = Dest.getAddress();
} else {
RetAddr = CGF.CreateMemTemp(RetTy, "tmp", &RetAllocaAddr);
llvm::TypeSize Size =
CGF.CGM.getDataLayout().getTypeAllocSize(CGF.ConvertTypeForMem(RetTy));
LifetimeSizePtr = CGF.EmitLifetimeStart(Size, RetAllocaAddr.getPointer());
if (LifetimeSizePtr) {
LifetimeStartInst =
cast<llvm::IntrinsicInst>(std::prev(Builder.GetInsertPoint()));
assert(LifetimeStartInst->getIntrinsicID() ==
llvm::Intrinsic::lifetime_start &&
"Last insertion wasn't a lifetime.start?");
CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
NormalEHLifetimeMarker, RetAllocaAddr, LifetimeSizePtr);
LifetimeEndBlock = CGF.EHStack.stable_begin();
}
}
RValue Src =
EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused,
Dest.isExternallyDestructed()));
if (!UseTemp)
return;
assert(Dest.isIgnored() || Dest.emitRawPointer(CGF) !=
Src.getAggregatePointer(E->getType(), CGF));
EmitFinalDestCopy(E->getType(), Src);
if (!RequiresDestruction && LifetimeStartInst) {
// If there's no dtor to run, the copy was the last use of our temporary.
// Since we're not guaranteed to be in an ExprWithCleanups, clean up
// eagerly.
CGF.DeactivateCleanupBlock(LifetimeEndBlock, LifetimeStartInst);
CGF.EmitLifetimeEnd(LifetimeSizePtr, RetAllocaAddr.getPointer());
}
}
/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src) {
assert(src.isAggregate() && "value must be aggregate value!");
LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddress(), type);
EmitFinalDestCopy(type, srcLV, CodeGenFunction::EVK_RValue);
}
/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
void AggExprEmitter::EmitFinalDestCopy(
QualType type, const LValue &src,
CodeGenFunction::ExprValueKind SrcValueKind) {
// 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;
// Copy non-trivial C structs here.
LValue DstLV = CGF.MakeAddrLValue(
Dest.getAddress(), Dest.isVolatile() ? type.withVolatile() : type);
if (SrcValueKind == CodeGenFunction::EVK_RValue) {
if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct) {
if (Dest.isPotentiallyAliased())
CGF.callCStructMoveAssignmentOperator(DstLV, src);
else
CGF.callCStructMoveConstructor(DstLV, src);
return;
}
} else {
if (type.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct) {
if (Dest.isPotentiallyAliased())
CGF.callCStructCopyAssignmentOperator(DstLV, src);
else
CGF.callCStructCopyConstructor(DstLV, src);
return;
}
}
AggValueSlot srcAgg = AggValueSlot::forLValue(
src, AggValueSlot::IsDestructed, needsGC(type), AggValueSlot::IsAliased,
AggValueSlot::MayOverlap);
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 = dest.getPreferredSize(CGF.getContext(), type);
llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
dest.getAddress(),
src.getAddress(),
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.
LValue DestLV = CGF.MakeAddrLValue(dest.getAddress(), type);
LValue SrcLV = CGF.MakeAddrLValue(src.getAddress(), type);
CGF.EmitAggregateCopy(DestLV, SrcLV, type, dest.mayOverlap(),
dest.isVolatile() || src.isVolatile());
}
/// 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");
Address ArrayPtr = Array.getAddress();
const ConstantArrayType *ArrayType =
Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
assert(ArrayType && "std::initializer_list constructed from non-array");
RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
RecordDecl::field_iterator Field = Record->field_begin();
assert(Field != Record->field_end() &&
Ctx.hasSameType(Field->getType()->getPointeeType(),
ArrayType->getElementType()) &&
"Expected std::initializer_list first field to be const E *");
// Start pointer.
AggValueSlot Dest = EnsureSlot(E->getType());
LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
llvm::Value *ArrayStart = ArrayPtr.emitRawPointer(CGF);
CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start);
++Field;
assert(Field != Record->field_end() &&
"Expected std::initializer_list to have two fields");
llvm::Value *Size = Builder.getInt(ArrayType->getSize());
LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) {
// Length.
CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
} else {
// End pointer.
assert(Field->getType()->isPointerType() &&
Ctx.hasSameType(Field->getType()->getPointeeType(),
ArrayType->getElementType()) &&
"Expected std::initializer_list second field to be const E *");
llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0);
llvm::Value *IdxEnd[] = { Zero, Size };
llvm::Value *ArrayEnd = Builder.CreateInBoundsGEP(
ArrayPtr.getElementType(), ArrayPtr.emitRawPointer(CGF), IdxEnd,
"arrayend");
CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength);
}
assert(++Field == Record->field_end() &&
"Expected std::initializer_list to only have two fields");
}
/// Determine if E is a trivial array filler, that is, one that is
/// equivalent to zero-initialization.
static bool isTrivialFiller(Expr *E) {
if (!E)
return true;
if (isa<ImplicitValueInitExpr>(E))
return true;
if (auto *ILE = dyn_cast<InitListExpr>(E)) {
if (ILE->getNumInits())
return false;
return isTrivialFiller(ILE->getArrayFiller());
}
if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E))
return Cons->getConstructor()->isDefaultConstructor() &&
Cons->getConstructor()->isTrivial();
// FIXME: Are there other cases where we can avoid emitting an initializer?
return false;
}
static void EmitHLSLAggregateSplatCast(CodeGenFunction &CGF, Address DestVal,
QualType DestTy, llvm::Value *SrcVal,
QualType SrcTy, SourceLocation Loc) {
// Flatten our destination
SmallVector<QualType> DestTypes; // Flattened type
SmallVector<std::pair<Address, llvm::Value *>, 16> StoreGEPList;
// ^^ Flattened accesses to DestVal we want to store into
CGF.FlattenAccessAndType(DestVal, DestTy, StoreGEPList, DestTypes);
assert(SrcTy->isScalarType() && "Invalid HLSL Aggregate splat cast.");
for (unsigned I = 0, Size = StoreGEPList.size(); I < Size; ++I) {
llvm::Value *Cast =
CGF.EmitScalarConversion(SrcVal, SrcTy, DestTypes[I], Loc);
// store back
llvm::Value *Idx = StoreGEPList[I].second;
if (Idx) {
llvm::Value *V =
CGF.Builder.CreateLoad(StoreGEPList[I].first, "load.for.insert");
Cast = CGF.Builder.CreateInsertElement(V, Cast, Idx);
}
CGF.Builder.CreateStore(Cast, StoreGEPList[I].first);
}
}
// emit a flat cast where the RHS is a scalar, including vector
static void EmitHLSLScalarFlatCast(CodeGenFunction &CGF, Address DestVal,
QualType DestTy, llvm::Value *SrcVal,
QualType SrcTy, SourceLocation Loc) {
// Flatten our destination
SmallVector<QualType, 16> DestTypes; // Flattened type
SmallVector<std::pair<Address, llvm::Value *>, 16> StoreGEPList;
// ^^ Flattened accesses to DestVal we want to store into
CGF.FlattenAccessAndType(DestVal, DestTy, StoreGEPList, DestTypes);
assert(SrcTy->isVectorType() && "HLSL Flat cast doesn't handle splatting.");
const VectorType *VT = SrcTy->getAs<VectorType>();
SrcTy = VT->getElementType();
assert(StoreGEPList.size() <= VT->getNumElements() &&
"Cannot perform HLSL flat cast when vector source \
object has less elements than flattened destination \
object.");
for (unsigned I = 0, Size = StoreGEPList.size(); I < Size; I++) {
llvm::Value *Load = CGF.Builder.CreateExtractElement(SrcVal, I, "vec.load");
llvm::Value *Cast =
CGF.EmitScalarConversion(Load, SrcTy, DestTypes[I], Loc);
// store back
llvm::Value *Idx = StoreGEPList[I].second;
if (Idx) {
llvm::Value *V =
CGF.Builder.CreateLoad(StoreGEPList[I].first, "load.for.insert");
Cast = CGF.Builder.CreateInsertElement(V, Cast, Idx);
}
CGF.Builder.CreateStore(Cast, StoreGEPList[I].first);
}
return;
}
// emit a flat cast where the RHS is an aggregate
static void EmitHLSLElementwiseCast(CodeGenFunction &CGF, Address DestVal,
QualType DestTy, Address SrcVal,
QualType SrcTy, SourceLocation Loc) {
// Flatten our destination
SmallVector<QualType, 16> DestTypes; // Flattened type
SmallVector<std::pair<Address, llvm::Value *>, 16> StoreGEPList;
// ^^ Flattened accesses to DestVal we want to store into
CGF.FlattenAccessAndType(DestVal, DestTy, StoreGEPList, DestTypes);
// Flatten our src
SmallVector<QualType, 16> SrcTypes; // Flattened type
SmallVector<std::pair<Address, llvm::Value *>, 16> LoadGEPList;
// ^^ Flattened accesses to SrcVal we want to load from
CGF.FlattenAccessAndType(SrcVal, SrcTy, LoadGEPList, SrcTypes);
assert(StoreGEPList.size() <= LoadGEPList.size() &&
"Cannot perform HLSL flat cast when flattened source object \
has less elements than flattened destination object.");
// apply casts to what we load from LoadGEPList
// and store result in Dest
for (unsigned I = 0, E = StoreGEPList.size(); I < E; I++) {
llvm::Value *Idx = LoadGEPList[I].second;
llvm::Value *Load = CGF.Builder.CreateLoad(LoadGEPList[I].first, "load");
Load =
Idx ? CGF.Builder.CreateExtractElement(Load, Idx, "vec.extract") : Load;
llvm::Value *Cast =
CGF.EmitScalarConversion(Load, SrcTypes[I], DestTypes[I], Loc);
// store back
Idx = StoreGEPList[I].second;
if (Idx) {
llvm::Value *V =
CGF.Builder.CreateLoad(StoreGEPList[I].first, "load.for.insert");
Cast = CGF.Builder.CreateInsertElement(V, Cast, Idx);
}
CGF.Builder.CreateStore(Cast, StoreGEPList[I].first);
}
}
/// Emit initialization of an array from an initializer list. ExprToVisit must
/// be either an InitListEpxr a CXXParenInitListExpr.
void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
QualType ArrayQTy, Expr *ExprToVisit,
ArrayRef<Expr *> Args, Expr *ArrayFiller) {
uint64_t NumInitElements = Args.size();
uint64_t NumArrayElements = AType->getNumElements();
for (const auto *Init : Args) {
if (const auto *Embed = dyn_cast<EmbedExpr>(Init->IgnoreParenImpCasts())) {
NumInitElements += Embed->getDataElementCount() - 1;
if (NumInitElements > NumArrayElements) {
NumInitElements = NumArrayElements;
break;
}
}
}
assert(NumInitElements <= NumArrayElements);
QualType elementType =
CGF.getContext().getAsArrayType(ArrayQTy)->getElementType();
CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
CharUnits elementAlign =
DestPtr.getAlignment().alignmentOfArrayElement(elementSize);
llvm::Type *llvmElementType = CGF.ConvertTypeForMem(elementType);
// Consider initializing the array by copying from a global. For this to be
// more efficient than per-element initialization, the size of the elements
// with explicit initializers should be large enough.
if (NumInitElements * elementSize.getQuantity() > 16 &&
elementType.isTriviallyCopyableType(CGF.getContext())) {
CodeGen::CodeGenModule &CGM = CGF.CGM;
ConstantEmitter Emitter(CGF);
QualType GVArrayQTy = CGM.getContext().getAddrSpaceQualType(
CGM.getContext().removeAddrSpaceQualType(ArrayQTy),
CGM.GetGlobalConstantAddressSpace());
LangAS AS = GVArrayQTy.getAddressSpace();
if (llvm::Constant *C =
Emitter.tryEmitForInitializer(ExprToVisit, AS, GVArrayQTy)) {
auto GV = new llvm::GlobalVariable(
CGM.getModule(), C->getType(),
/* isConstant= */ true, llvm::GlobalValue::PrivateLinkage, C,
"constinit",
/* InsertBefore= */ nullptr, llvm::GlobalVariable::NotThreadLocal,
CGM.getContext().getTargetAddressSpace(AS));
Emitter.finalize(GV);
CharUnits Align = CGM.getContext().getTypeAlignInChars(GVArrayQTy);
GV->setAlignment(Align.getAsAlign());
Address GVAddr(GV, GV->getValueType(), Align);
EmitFinalDestCopy(ArrayQTy, CGF.MakeAddrLValue(GVAddr, GVArrayQTy));
return;
}
}
// 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();
Address endOfInit = Address::invalid();
CodeGenFunction::CleanupDeactivationScope deactivation(CGF);
llvm::Value *begin = DestPtr.emitRawPointer(CGF);
if (dtorKind) {
CodeGenFunction::AllocaTrackerRAII allocaTracker(CGF);
// 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.
llvm::Instruction *dominatingIP =
Builder.CreateFlagLoad(llvm::ConstantInt::getNullValue(CGF.Int8PtrTy));
endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(),
"arrayinit.endOfInit");
Builder.CreateStore(begin, endOfInit);
CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
elementAlign,
CGF.getDestroyer(dtorKind));
cast<EHCleanupScope>(*CGF.EHStack.find(CGF.EHStack.stable_begin()))
.AddAuxAllocas(allocaTracker.Take());
CGF.DeferredDeactivationCleanupStack.push_back(
{CGF.EHStack.stable_begin(), dominatingIP});
}
llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
auto Emit = [&](Expr *Init, uint64_t ArrayIndex) {
llvm::Value *element = begin;
if (ArrayIndex > 0) {
element = Builder.CreateInBoundsGEP(
llvmElementType, begin,
llvm::ConstantInt::get(CGF.SizeTy, ArrayIndex), "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.isValid())
Builder.CreateStore(element, endOfInit);
}
LValue elementLV = CGF.MakeAddrLValue(
Address(element, llvmElementType, elementAlign), elementType);
EmitInitializationToLValue(Init, elementLV);
return true;
};
unsigned ArrayIndex = 0;
// Emit the explicit initializers.
for (uint64_t i = 0; i != NumInitElements; ++i) {
if (ArrayIndex >= NumInitElements)
break;
if (auto *EmbedS = dyn_cast<EmbedExpr>(Args[i]->IgnoreParenImpCasts())) {
EmbedS->doForEachDataElement(Emit, ArrayIndex);
} else {
Emit(Args[i], ArrayIndex);
ArrayIndex++;
}
}
// Check whether there's a non-trivial array-fill expression.
bool hasTrivialFiller = isTrivialFiller(ArrayFiller);
// 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.
llvm::Value *element = begin;
if (NumInitElements) {
element = Builder.CreateInBoundsGEP(
llvmElementType, element,
llvm::ConstantInt::get(CGF.SizeTy, NumInitElements),
"arrayinit.start");
if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
}
// Compute the end of the array.
llvm::Value *end = Builder.CreateInBoundsGEP(
llvmElementType, 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.
{
// C++1z [class.temporary]p5:
// when a default constructor is called to initialize an element of
// an array with no corresponding initializer [...] the destruction of
// every temporary created in a default argument is sequenced before
// the construction of the next array element, if any
CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
LValue elementLV = CGF.MakeAddrLValue(
Address(currentElement, llvmElementType, elementAlign), elementType);
if (ArrayFiller)
EmitInitializationToLValue(ArrayFiller, elementLV);
else
EmitNullInitializationToLValue(elementLV);
}
// Move on to the next element.
llvm::Value *nextElement = Builder.CreateInBoundsGEP(
llvmElementType, currentElement, one, "arrayinit.next");
// Tell the EH cleanup that we finished with the last element.
if (endOfInit.isValid()) 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);
}
}
//===----------------------------------------------------------------------===//
// Visitor Methods
//===----------------------------------------------------------------------===//
void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
Visit(E->getSubExpr());
}
void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
// If this is a unique OVE, just visit its source expression.
if (e->isUnique())
Visit(e->getSourceExpr());
else
EmitFinalDestCopy(e->getType(), CGF.getOrCreateOpaqueLValueMapping(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());
// Block-scope compound literals are destroyed at the end of the enclosing
// scope in C.
bool Destruct =
!CGF.getLangOpts().CPlusPlus && !Slot.isExternallyDestructed();
if (Destruct)
Slot.setExternallyDestructed();
CGF.EmitAggExpr(E->getInitializer(), Slot);
if (Destruct)
if (QualType::DestructionKind DtorKind = E->getType().isDestructedType())
CGF.pushLifetimeExtendedDestroy(
CGF.getCleanupKind(DtorKind), Slot.getAddress(), E->getType(),
CGF.getDestroyer(DtorKind), DtorKind & EHCleanup);
}
/// Attempt to look through various unimportant expressions to find a
/// cast of the given kind.
static Expr *findPeephole(Expr *op, CastKind kind, const ASTContext &ctx) {
op = op->IgnoreParenNoopCasts(ctx);
if (auto castE = dyn_cast<CastExpr>(op)) {
if (castE->getCastKind() == kind)
return castE->getSubExpr();
}
return nullptr;
}
void AggExprEmitter::VisitCastExpr(CastExpr *E) {
if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
CGF.CGM.EmitExplicitCastExprType(ECE, &CGF);
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: {
// Evaluate even if the destination is ignored.
if (Dest.isIgnored()) {
CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
/*ignoreResult=*/true);
break;
}
// GCC union extension
QualType Ty = E->getSubExpr()->getType();
Address CastPtr = Dest.getAddress().withElementType(CGF.ConvertType(Ty));
EmitInitializationToLValue(E->getSubExpr(),
CGF.MakeAddrLValue(CastPtr, Ty));
break;
}
case CK_LValueToRValueBitCast: {
if (Dest.isIgnored()) {
CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
/*ignoreResult=*/true);
break;
}
LValue SourceLV = CGF.EmitLValue(E->getSubExpr());
Address SourceAddress = SourceLV.getAddress().withElementType(CGF.Int8Ty);
Address DestAddress = Dest.getAddress().withElementType(CGF.Int8Ty);
llvm::Value *SizeVal = llvm::ConstantInt::get(
CGF.SizeTy,
CGF.getContext().getTypeSizeInChars(E->getType()).getQuantity());
Builder.CreateMemCpy(DestAddress, SourceAddress, SizeVal);
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, CGF.getContext())) {
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 initialize
// the padding at the end, but this is simpler.)
if (!Dest.isZeroed())
CGF.EmitNullInitialization(Dest.getAddress(), atomicType);
// Build a GEP to refer to the subobject.
Address valueAddr =
CGF.Builder.CreateStructGEP(valueDest.getAddress(), 0);
valueDest = AggValueSlot::forAddr(valueAddr,
valueDest.getQualifiers(),
valueDest.isExternallyDestructed(),
valueDest.requiresGCollection(),
valueDest.isPotentiallyAliased(),
AggValueSlot::DoesNotOverlap,
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);
Address valueAddr = Builder.CreateStructGEP(atomicSlot.getAddress(), 0);
RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
return EmitFinalDestCopy(valueType, rvalue);
}
case CK_AddressSpaceConversion:
return Visit(E->getSubExpr());
case CK_LValueToRValue:
// If we're loading from a volatile type, force the destination
// into existence.
if (E->getSubExpr()->getType().isVolatileQualified()) {
bool Destruct =
!Dest.isExternallyDestructed() &&
E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct;
if (Destruct)
Dest.setExternallyDestructed();
EnsureDest(E->getType());
Visit(E->getSubExpr());
if (Destruct)
CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
E->getType());
return;
}
[[fallthrough]];
case CK_HLSLArrayRValue:
Visit(E->getSubExpr());
break;
case CK_HLSLAggregateSplatCast: {
Expr *Src = E->getSubExpr();
QualType SrcTy = Src->getType();
RValue RV = CGF.EmitAnyExpr(Src);
QualType DestTy = E->getType();
Address DestVal = Dest.getAddress();
SourceLocation Loc = E->getExprLoc();
assert(RV.isScalar() && "RHS of HLSL splat cast must be a scalar.");
llvm::Value *SrcVal = RV.getScalarVal();