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2339 lines
86 KiB
2339 lines
86 KiB
//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code to emit Constant Expr nodes as LLVM code.
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//
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//===----------------------------------------------------------------------===//
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#include "CGCXXABI.h"
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#include "CGObjCRuntime.h"
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#include "CGRecordLayout.h"
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#include "CodeGenFunction.h"
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#include "CodeGenModule.h"
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#include "ConstantEmitter.h"
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#include "TargetInfo.h"
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#include "clang/AST/APValue.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/Basic/Builtins.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/Sequence.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalVariable.h"
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using namespace clang;
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using namespace CodeGen;
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//===----------------------------------------------------------------------===//
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// ConstantAggregateBuilder
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//===----------------------------------------------------------------------===//
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namespace {
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class ConstExprEmitter;
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struct ConstantAggregateBuilderUtils {
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CodeGenModule &CGM;
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ConstantAggregateBuilderUtils(CodeGenModule &CGM) : CGM(CGM) {}
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CharUnits getAlignment(const llvm::Constant *C) const {
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return CharUnits::fromQuantity(
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CGM.getDataLayout().getABITypeAlignment(C->getType()));
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}
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CharUnits getSize(llvm::Type *Ty) const {
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return CharUnits::fromQuantity(CGM.getDataLayout().getTypeAllocSize(Ty));
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}
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CharUnits getSize(const llvm::Constant *C) const {
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return getSize(C->getType());
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}
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llvm::Constant *getPadding(CharUnits PadSize) const {
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llvm::Type *Ty = CGM.Int8Ty;
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if (PadSize > CharUnits::One())
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Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
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return llvm::UndefValue::get(Ty);
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}
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llvm::Constant *getZeroes(CharUnits ZeroSize) const {
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llvm::Type *Ty = llvm::ArrayType::get(CGM.Int8Ty, ZeroSize.getQuantity());
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return llvm::ConstantAggregateZero::get(Ty);
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}
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};
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/// Incremental builder for an llvm::Constant* holding a struct or array
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/// constant.
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class ConstantAggregateBuilder : private ConstantAggregateBuilderUtils {
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/// The elements of the constant. These two arrays must have the same size;
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/// Offsets[i] describes the offset of Elems[i] within the constant. The
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/// elements are kept in increasing offset order, and we ensure that there
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/// is no overlap: Offsets[i+1] >= Offsets[i] + getSize(Elemes[i]).
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///
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/// This may contain explicit padding elements (in order to create a
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/// natural layout), but need not. Gaps between elements are implicitly
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/// considered to be filled with undef.
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llvm::SmallVector<llvm::Constant*, 32> Elems;
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llvm::SmallVector<CharUnits, 32> Offsets;
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/// The size of the constant (the maximum end offset of any added element).
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/// May be larger than the end of Elems.back() if we split the last element
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/// and removed some trailing undefs.
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CharUnits Size = CharUnits::Zero();
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/// This is true only if laying out Elems in order as the elements of a
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/// non-packed LLVM struct will give the correct layout.
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bool NaturalLayout = true;
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bool split(size_t Index, CharUnits Hint);
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Optional<size_t> splitAt(CharUnits Pos);
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static llvm::Constant *buildFrom(CodeGenModule &CGM,
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ArrayRef<llvm::Constant *> Elems,
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ArrayRef<CharUnits> Offsets,
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CharUnits StartOffset, CharUnits Size,
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bool NaturalLayout, llvm::Type *DesiredTy,
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bool AllowOversized);
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public:
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ConstantAggregateBuilder(CodeGenModule &CGM)
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: ConstantAggregateBuilderUtils(CGM) {}
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/// Update or overwrite the value starting at \p Offset with \c C.
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///
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/// \param AllowOverwrite If \c true, this constant might overwrite (part of)
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/// a constant that has already been added. This flag is only used to
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/// detect bugs.
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bool add(llvm::Constant *C, CharUnits Offset, bool AllowOverwrite);
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/// Update or overwrite the bits starting at \p OffsetInBits with \p Bits.
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bool addBits(llvm::APInt Bits, uint64_t OffsetInBits, bool AllowOverwrite);
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/// Attempt to condense the value starting at \p Offset to a constant of type
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/// \p DesiredTy.
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void condense(CharUnits Offset, llvm::Type *DesiredTy);
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/// Produce a constant representing the entire accumulated value, ideally of
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/// the specified type. If \p AllowOversized, the constant might be larger
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/// than implied by \p DesiredTy (eg, if there is a flexible array member).
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/// Otherwise, the constant will be of exactly the same size as \p DesiredTy
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/// even if we can't represent it as that type.
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llvm::Constant *build(llvm::Type *DesiredTy, bool AllowOversized) const {
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return buildFrom(CGM, Elems, Offsets, CharUnits::Zero(), Size,
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NaturalLayout, DesiredTy, AllowOversized);
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}
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};
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template<typename Container, typename Range = std::initializer_list<
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typename Container::value_type>>
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
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assert(BeginOff <= EndOff && "invalid replacement range");
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llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
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}
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bool ConstantAggregateBuilder::add(llvm::Constant *C, CharUnits Offset,
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bool AllowOverwrite) {
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// Common case: appending to a layout.
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if (Offset >= Size) {
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CharUnits Align = getAlignment(C);
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CharUnits AlignedSize = Size.alignTo(Align);
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if (AlignedSize > Offset || Offset.alignTo(Align) != Offset)
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NaturalLayout = false;
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else if (AlignedSize < Offset) {
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Elems.push_back(getPadding(Offset - Size));
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Offsets.push_back(Size);
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}
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Elems.push_back(C);
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Offsets.push_back(Offset);
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Size = Offset + getSize(C);
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return true;
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}
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// Uncommon case: constant overlaps what we've already created.
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llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
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if (!FirstElemToReplace)
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return false;
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CharUnits CSize = getSize(C);
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llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + CSize);
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if (!LastElemToReplace)
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return false;
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assert((FirstElemToReplace == LastElemToReplace || AllowOverwrite) &&
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"unexpectedly overwriting field");
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replace(Elems, *FirstElemToReplace, *LastElemToReplace, {C});
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replace(Offsets, *FirstElemToReplace, *LastElemToReplace, {Offset});
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Size = std::max(Size, Offset + CSize);
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NaturalLayout = false;
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return true;
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}
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bool ConstantAggregateBuilder::addBits(llvm::APInt Bits, uint64_t OffsetInBits,
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bool AllowOverwrite) {
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const ASTContext &Context = CGM.getContext();
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const uint64_t CharWidth = CGM.getContext().getCharWidth();
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// Offset of where we want the first bit to go within the bits of the
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// current char.
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unsigned OffsetWithinChar = OffsetInBits % CharWidth;
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// We split bit-fields up into individual bytes. Walk over the bytes and
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// update them.
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for (CharUnits OffsetInChars =
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Context.toCharUnitsFromBits(OffsetInBits - OffsetWithinChar);
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/**/; ++OffsetInChars) {
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// Number of bits we want to fill in this char.
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unsigned WantedBits =
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std::min((uint64_t)Bits.getBitWidth(), CharWidth - OffsetWithinChar);
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// Get a char containing the bits we want in the right places. The other
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// bits have unspecified values.
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llvm::APInt BitsThisChar = Bits;
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if (BitsThisChar.getBitWidth() < CharWidth)
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BitsThisChar = BitsThisChar.zext(CharWidth);
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if (CGM.getDataLayout().isBigEndian()) {
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// Figure out how much to shift by. We may need to left-shift if we have
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// less than one byte of Bits left.
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int Shift = Bits.getBitWidth() - CharWidth + OffsetWithinChar;
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if (Shift > 0)
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BitsThisChar.lshrInPlace(Shift);
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else if (Shift < 0)
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BitsThisChar = BitsThisChar.shl(-Shift);
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} else {
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BitsThisChar = BitsThisChar.shl(OffsetWithinChar);
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}
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if (BitsThisChar.getBitWidth() > CharWidth)
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BitsThisChar = BitsThisChar.trunc(CharWidth);
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if (WantedBits == CharWidth) {
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// Got a full byte: just add it directly.
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add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
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OffsetInChars, AllowOverwrite);
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} else {
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// Partial byte: update the existing integer if there is one. If we
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// can't split out a 1-CharUnit range to update, then we can't add
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// these bits and fail the entire constant emission.
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llvm::Optional<size_t> FirstElemToUpdate = splitAt(OffsetInChars);
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if (!FirstElemToUpdate)
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return false;
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llvm::Optional<size_t> LastElemToUpdate =
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splitAt(OffsetInChars + CharUnits::One());
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if (!LastElemToUpdate)
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return false;
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assert(*LastElemToUpdate - *FirstElemToUpdate < 2 &&
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"should have at most one element covering one byte");
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// Figure out which bits we want and discard the rest.
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llvm::APInt UpdateMask(CharWidth, 0);
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if (CGM.getDataLayout().isBigEndian())
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UpdateMask.setBits(CharWidth - OffsetWithinChar - WantedBits,
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CharWidth - OffsetWithinChar);
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else
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UpdateMask.setBits(OffsetWithinChar, OffsetWithinChar + WantedBits);
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BitsThisChar &= UpdateMask;
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if (*FirstElemToUpdate == *LastElemToUpdate ||
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Elems[*FirstElemToUpdate]->isNullValue() ||
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isa<llvm::UndefValue>(Elems[*FirstElemToUpdate])) {
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// All existing bits are either zero or undef.
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add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
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OffsetInChars, /*AllowOverwrite*/ true);
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} else {
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llvm::Constant *&ToUpdate = Elems[*FirstElemToUpdate];
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// In order to perform a partial update, we need the existing bitwise
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// value, which we can only extract for a constant int.
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auto *CI = dyn_cast<llvm::ConstantInt>(ToUpdate);
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if (!CI)
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return false;
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// Because this is a 1-CharUnit range, the constant occupying it must
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// be exactly one CharUnit wide.
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assert(CI->getBitWidth() == CharWidth && "splitAt failed");
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assert((!(CI->getValue() & UpdateMask) || AllowOverwrite) &&
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"unexpectedly overwriting bitfield");
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BitsThisChar |= (CI->getValue() & ~UpdateMask);
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ToUpdate = llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar);
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}
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}
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// Stop if we've added all the bits.
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if (WantedBits == Bits.getBitWidth())
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break;
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// Remove the consumed bits from Bits.
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if (!CGM.getDataLayout().isBigEndian())
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Bits.lshrInPlace(WantedBits);
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Bits = Bits.trunc(Bits.getBitWidth() - WantedBits);
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// The remanining bits go at the start of the following bytes.
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OffsetWithinChar = 0;
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}
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return true;
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}
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/// Returns a position within Elems and Offsets such that all elements
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/// before the returned index end before Pos and all elements at or after
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/// the returned index begin at or after Pos. Splits elements as necessary
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/// to ensure this. Returns None if we find something we can't split.
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Optional<size_t> ConstantAggregateBuilder::splitAt(CharUnits Pos) {
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if (Pos >= Size)
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return Offsets.size();
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while (true) {
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auto FirstAfterPos = llvm::upper_bound(Offsets, Pos);
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if (FirstAfterPos == Offsets.begin())
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return 0;
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// If we already have an element starting at Pos, we're done.
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size_t LastAtOrBeforePosIndex = FirstAfterPos - Offsets.begin() - 1;
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if (Offsets[LastAtOrBeforePosIndex] == Pos)
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return LastAtOrBeforePosIndex;
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// We found an element starting before Pos. Check for overlap.
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if (Offsets[LastAtOrBeforePosIndex] +
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getSize(Elems[LastAtOrBeforePosIndex]) <= Pos)
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return LastAtOrBeforePosIndex + 1;
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// Try to decompose it into smaller constants.
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if (!split(LastAtOrBeforePosIndex, Pos))
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return None;
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}
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}
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/// Split the constant at index Index, if possible. Return true if we did.
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/// Hint indicates the location at which we'd like to split, but may be
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/// ignored.
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bool ConstantAggregateBuilder::split(size_t Index, CharUnits Hint) {
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NaturalLayout = false;
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llvm::Constant *C = Elems[Index];
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CharUnits Offset = Offsets[Index];
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if (auto *CA = dyn_cast<llvm::ConstantAggregate>(C)) {
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// Expand the sequence into its contained elements.
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// FIXME: This assumes vector elements are byte-sized.
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replace(Elems, Index, Index + 1,
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llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
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[&](unsigned Op) { return CA->getOperand(Op); }));
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if (isa<llvm::ArrayType>(CA->getType()) ||
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isa<llvm::VectorType>(CA->getType())) {
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// Array or vector.
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llvm::Type *ElemTy =
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llvm::GetElementPtrInst::getTypeAtIndex(CA->getType(), (uint64_t)0);
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CharUnits ElemSize = getSize(ElemTy);
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replace(
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Offsets, Index, Index + 1,
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llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
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[&](unsigned Op) { return Offset + Op * ElemSize; }));
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} else {
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// Must be a struct.
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auto *ST = cast<llvm::StructType>(CA->getType());
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const llvm::StructLayout *Layout =
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CGM.getDataLayout().getStructLayout(ST);
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replace(Offsets, Index, Index + 1,
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llvm::map_range(
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llvm::seq(0u, CA->getNumOperands()), [&](unsigned Op) {
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return Offset + CharUnits::fromQuantity(
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Layout->getElementOffset(Op));
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}));
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}
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return true;
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}
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if (auto *CDS = dyn_cast<llvm::ConstantDataSequential>(C)) {
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// Expand the sequence into its contained elements.
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// FIXME: This assumes vector elements are byte-sized.
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// FIXME: If possible, split into two ConstantDataSequentials at Hint.
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CharUnits ElemSize = getSize(CDS->getElementType());
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replace(Elems, Index, Index + 1,
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llvm::map_range(llvm::seq(0u, CDS->getNumElements()),
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[&](unsigned Elem) {
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return CDS->getElementAsConstant(Elem);
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}));
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replace(Offsets, Index, Index + 1,
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llvm::map_range(
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llvm::seq(0u, CDS->getNumElements()),
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[&](unsigned Elem) { return Offset + Elem * ElemSize; }));
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return true;
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}
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if (isa<llvm::ConstantAggregateZero>(C)) {
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// Split into two zeros at the hinted offset.
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CharUnits ElemSize = getSize(C);
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assert(Hint > Offset && Hint < Offset + ElemSize && "nothing to split");
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replace(Elems, Index, Index + 1,
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{getZeroes(Hint - Offset), getZeroes(Offset + ElemSize - Hint)});
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replace(Offsets, Index, Index + 1, {Offset, Hint});
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return true;
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}
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if (isa<llvm::UndefValue>(C)) {
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// Drop undef; it doesn't contribute to the final layout.
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replace(Elems, Index, Index + 1, {});
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replace(Offsets, Index, Index + 1, {});
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return true;
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}
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// FIXME: We could split a ConstantInt if the need ever arose.
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// We don't need to do this to handle bit-fields because we always eagerly
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// split them into 1-byte chunks.
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return false;
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}
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static llvm::Constant *
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EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
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llvm::Type *CommonElementType, unsigned ArrayBound,
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SmallVectorImpl<llvm::Constant *> &Elements,
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llvm::Constant *Filler);
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llvm::Constant *ConstantAggregateBuilder::buildFrom(
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CodeGenModule &CGM, ArrayRef<llvm::Constant *> Elems,
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ArrayRef<CharUnits> Offsets, CharUnits StartOffset, CharUnits Size,
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bool NaturalLayout, llvm::Type *DesiredTy, bool AllowOversized) {
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ConstantAggregateBuilderUtils Utils(CGM);
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if (Elems.empty())
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return llvm::UndefValue::get(DesiredTy);
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auto Offset = [&](size_t I) { return Offsets[I] - StartOffset; };
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// If we want an array type, see if all the elements are the same type and
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// appropriately spaced.
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if (llvm::ArrayType *ATy = dyn_cast<llvm::ArrayType>(DesiredTy)) {
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assert(!AllowOversized && "oversized array emission not supported");
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bool CanEmitArray = true;
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llvm::Type *CommonType = Elems[0]->getType();
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llvm::Constant *Filler = llvm::Constant::getNullValue(CommonType);
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CharUnits ElemSize = Utils.getSize(ATy->getElementType());
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SmallVector<llvm::Constant*, 32> ArrayElements;
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for (size_t I = 0; I != Elems.size(); ++I) {
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// Skip zeroes; we'll use a zero value as our array filler.
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if (Elems[I]->isNullValue())
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continue;
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// All remaining elements must be the same type.
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if (Elems[I]->getType() != CommonType ||
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Offset(I) % ElemSize != 0) {
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CanEmitArray = false;
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break;
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}
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ArrayElements.resize(Offset(I) / ElemSize + 1, Filler);
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ArrayElements.back() = Elems[I];
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}
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if (CanEmitArray) {
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return EmitArrayConstant(CGM, ATy, CommonType, ATy->getNumElements(),
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ArrayElements, Filler);
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}
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// Can't emit as an array, carry on to emit as a struct.
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}
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CharUnits DesiredSize = Utils.getSize(DesiredTy);
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CharUnits Align = CharUnits::One();
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for (llvm::Constant *C : Elems)
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Align = std::max(Align, Utils.getAlignment(C));
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CharUnits AlignedSize = Size.alignTo(Align);
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bool Packed = false;
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ArrayRef<llvm::Constant*> UnpackedElems = Elems;
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llvm::SmallVector<llvm::Constant*, 32> UnpackedElemStorage;
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if ((DesiredSize < AlignedSize && !AllowOversized) ||
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DesiredSize.alignTo(Align) != DesiredSize) {
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// The natural layout would be the wrong size; force use of a packed layout.
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NaturalLayout = false;
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Packed = true;
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} else if (DesiredSize > AlignedSize) {
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// The constant would be too small. Add padding to fix it.
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UnpackedElemStorage.assign(Elems.begin(), Elems.end());
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UnpackedElemStorage.push_back(Utils.getPadding(DesiredSize - Size));
|
|
UnpackedElems = UnpackedElemStorage;
|
|
}
|
|
|
|
// If we don't have a natural layout, insert padding as necessary.
|
|
// As we go, double-check to see if we can actually just emit Elems
|
|
// as a non-packed struct and do so opportunistically if possible.
|
|
llvm::SmallVector<llvm::Constant*, 32> PackedElems;
|
|
if (!NaturalLayout) {
|
|
CharUnits SizeSoFar = CharUnits::Zero();
|
|
for (size_t I = 0; I != Elems.size(); ++I) {
|
|
CharUnits Align = Utils.getAlignment(Elems[I]);
|
|
CharUnits NaturalOffset = SizeSoFar.alignTo(Align);
|
|
CharUnits DesiredOffset = Offset(I);
|
|
assert(DesiredOffset >= SizeSoFar && "elements out of order");
|
|
|
|
if (DesiredOffset != NaturalOffset)
|
|
Packed = true;
|
|
if (DesiredOffset != SizeSoFar)
|
|
PackedElems.push_back(Utils.getPadding(DesiredOffset - SizeSoFar));
|
|
PackedElems.push_back(Elems[I]);
|
|
SizeSoFar = DesiredOffset + Utils.getSize(Elems[I]);
|
|
}
|
|
// If we're using the packed layout, pad it out to the desired size if
|
|
// necessary.
|
|
if (Packed) {
|
|
assert((SizeSoFar <= DesiredSize || AllowOversized) &&
|
|
"requested size is too small for contents");
|
|
if (SizeSoFar < DesiredSize)
|
|
PackedElems.push_back(Utils.getPadding(DesiredSize - SizeSoFar));
|
|
}
|
|
}
|
|
|
|
llvm::StructType *STy = llvm::ConstantStruct::getTypeForElements(
|
|
CGM.getLLVMContext(), Packed ? PackedElems : UnpackedElems, Packed);
|
|
|
|
// Pick the type to use. If the type is layout identical to the desired
|
|
// type then use it, otherwise use whatever the builder produced for us.
|
|
if (llvm::StructType *DesiredSTy = dyn_cast<llvm::StructType>(DesiredTy)) {
|
|
if (DesiredSTy->isLayoutIdentical(STy))
|
|
STy = DesiredSTy;
|
|
}
|
|
|
|
return llvm::ConstantStruct::get(STy, Packed ? PackedElems : UnpackedElems);
|
|
}
|
|
|
|
void ConstantAggregateBuilder::condense(CharUnits Offset,
|
|
llvm::Type *DesiredTy) {
|
|
CharUnits Size = getSize(DesiredTy);
|
|
|
|
llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
|
|
if (!FirstElemToReplace)
|
|
return;
|
|
size_t First = *FirstElemToReplace;
|
|
|
|
llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + Size);
|
|
if (!LastElemToReplace)
|
|
return;
|
|
size_t Last = *LastElemToReplace;
|
|
|
|
size_t Length = Last - First;
|
|
if (Length == 0)
|
|
return;
|
|
|
|
if (Length == 1 && Offsets[First] == Offset &&
|
|
getSize(Elems[First]) == Size) {
|
|
// Re-wrap single element structs if necessary. Otherwise, leave any single
|
|
// element constant of the right size alone even if it has the wrong type.
|
|
auto *STy = dyn_cast<llvm::StructType>(DesiredTy);
|
|
if (STy && STy->getNumElements() == 1 &&
|
|
STy->getElementType(0) == Elems[First]->getType())
|
|
Elems[First] = llvm::ConstantStruct::get(STy, Elems[First]);
|
|
return;
|
|
}
|
|
|
|
llvm::Constant *Replacement = buildFrom(
|
|
CGM, makeArrayRef(Elems).slice(First, Length),
|
|
makeArrayRef(Offsets).slice(First, Length), Offset, getSize(DesiredTy),
|
|
/*known to have natural layout=*/false, DesiredTy, false);
|
|
replace(Elems, First, Last, {Replacement});
|
|
replace(Offsets, First, Last, {Offset});
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ConstStructBuilder
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
class ConstStructBuilder {
|
|
CodeGenModule &CGM;
|
|
ConstantEmitter &Emitter;
|
|
ConstantAggregateBuilder &Builder;
|
|
CharUnits StartOffset;
|
|
|
|
public:
|
|
static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
|
|
InitListExpr *ILE, QualType StructTy);
|
|
static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
|
|
const APValue &Value, QualType ValTy);
|
|
static bool UpdateStruct(ConstantEmitter &Emitter,
|
|
ConstantAggregateBuilder &Const, CharUnits Offset,
|
|
InitListExpr *Updater);
|
|
|
|
private:
|
|
ConstStructBuilder(ConstantEmitter &Emitter,
|
|
ConstantAggregateBuilder &Builder, CharUnits StartOffset)
|
|
: CGM(Emitter.CGM), Emitter(Emitter), Builder(Builder),
|
|
StartOffset(StartOffset) {}
|
|
|
|
bool AppendField(const FieldDecl *Field, uint64_t FieldOffset,
|
|
llvm::Constant *InitExpr, bool AllowOverwrite = false);
|
|
|
|
bool AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst,
|
|
bool AllowOverwrite = false);
|
|
|
|
bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
|
|
llvm::ConstantInt *InitExpr, bool AllowOverwrite = false);
|
|
|
|
bool Build(InitListExpr *ILE, bool AllowOverwrite);
|
|
bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
|
|
const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
|
|
llvm::Constant *Finalize(QualType Ty);
|
|
};
|
|
|
|
bool ConstStructBuilder::AppendField(
|
|
const FieldDecl *Field, uint64_t FieldOffset, llvm::Constant *InitCst,
|
|
bool AllowOverwrite) {
|
|
const ASTContext &Context = CGM.getContext();
|
|
|
|
CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
|
|
|
|
return AppendBytes(FieldOffsetInChars, InitCst, AllowOverwrite);
|
|
}
|
|
|
|
bool ConstStructBuilder::AppendBytes(CharUnits FieldOffsetInChars,
|
|
llvm::Constant *InitCst,
|
|
bool AllowOverwrite) {
|
|
return Builder.add(InitCst, StartOffset + FieldOffsetInChars, AllowOverwrite);
|
|
}
|
|
|
|
bool ConstStructBuilder::AppendBitField(
|
|
const FieldDecl *Field, uint64_t FieldOffset, llvm::ConstantInt *CI,
|
|
bool AllowOverwrite) {
|
|
const CGRecordLayout &RL =
|
|
CGM.getTypes().getCGRecordLayout(Field->getParent());
|
|
const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
|
|
llvm::APInt FieldValue = CI->getValue();
|
|
|
|
// Promote the size of FieldValue if necessary
|
|
// FIXME: This should never occur, but currently it can because initializer
|
|
// constants are cast to bool, and because clang is not enforcing bitfield
|
|
// width limits.
|
|
if (Info.Size > FieldValue.getBitWidth())
|
|
FieldValue = FieldValue.zext(Info.Size);
|
|
|
|
// Truncate the size of FieldValue to the bit field size.
|
|
if (Info.Size < FieldValue.getBitWidth())
|
|
FieldValue = FieldValue.trunc(Info.Size);
|
|
|
|
return Builder.addBits(FieldValue,
|
|
CGM.getContext().toBits(StartOffset) + FieldOffset,
|
|
AllowOverwrite);
|
|
}
|
|
|
|
static bool EmitDesignatedInitUpdater(ConstantEmitter &Emitter,
|
|
ConstantAggregateBuilder &Const,
|
|
CharUnits Offset, QualType Type,
|
|
InitListExpr *Updater) {
|
|
if (Type->isRecordType())
|
|
return ConstStructBuilder::UpdateStruct(Emitter, Const, Offset, Updater);
|
|
|
|
auto CAT = Emitter.CGM.getContext().getAsConstantArrayType(Type);
|
|
if (!CAT)
|
|
return false;
|
|
QualType ElemType = CAT->getElementType();
|
|
CharUnits ElemSize = Emitter.CGM.getContext().getTypeSizeInChars(ElemType);
|
|
llvm::Type *ElemTy = Emitter.CGM.getTypes().ConvertTypeForMem(ElemType);
|
|
|
|
llvm::Constant *FillC = nullptr;
|
|
if (Expr *Filler = Updater->getArrayFiller()) {
|
|
if (!isa<NoInitExpr>(Filler)) {
|
|
FillC = Emitter.tryEmitAbstractForMemory(Filler, ElemType);
|
|
if (!FillC)
|
|
return false;
|
|
}
|
|
}
|
|
|
|
unsigned NumElementsToUpdate =
|
|
FillC ? CAT->getSize().getZExtValue() : Updater->getNumInits();
|
|
for (unsigned I = 0; I != NumElementsToUpdate; ++I, Offset += ElemSize) {
|
|
Expr *Init = nullptr;
|
|
if (I < Updater->getNumInits())
|
|
Init = Updater->getInit(I);
|
|
|
|
if (!Init && FillC) {
|
|
if (!Const.add(FillC, Offset, true))
|
|
return false;
|
|
} else if (!Init || isa<NoInitExpr>(Init)) {
|
|
continue;
|
|
} else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) {
|
|
if (!EmitDesignatedInitUpdater(Emitter, Const, Offset, ElemType,
|
|
ChildILE))
|
|
return false;
|
|
// Attempt to reduce the array element to a single constant if necessary.
|
|
Const.condense(Offset, ElemTy);
|
|
} else {
|
|
llvm::Constant *Val = Emitter.tryEmitPrivateForMemory(Init, ElemType);
|
|
if (!Const.add(Val, Offset, true))
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
bool ConstStructBuilder::Build(InitListExpr *ILE, bool AllowOverwrite) {
|
|
RecordDecl *RD = ILE->getType()->castAs<RecordType>()->getDecl();
|
|
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
|
|
|
|
unsigned FieldNo = -1;
|
|
unsigned ElementNo = 0;
|
|
|
|
// Bail out if we have base classes. We could support these, but they only
|
|
// arise in C++1z where we will have already constant folded most interesting
|
|
// cases. FIXME: There are still a few more cases we can handle this way.
|
|
if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
|
|
if (CXXRD->getNumBases())
|
|
return false;
|
|
|
|
for (FieldDecl *Field : RD->fields()) {
|
|
++FieldNo;
|
|
|
|
// If this is a union, skip all the fields that aren't being initialized.
|
|
if (RD->isUnion() &&
|
|
!declaresSameEntity(ILE->getInitializedFieldInUnion(), Field))
|
|
continue;
|
|
|
|
// Don't emit anonymous bitfields or zero-sized fields.
|
|
if (Field->isUnnamedBitfield() || Field->isZeroSize(CGM.getContext()))
|
|
continue;
|
|
|
|
// Get the initializer. A struct can include fields without initializers,
|
|
// we just use explicit null values for them.
|
|
Expr *Init = nullptr;
|
|
if (ElementNo < ILE->getNumInits())
|
|
Init = ILE->getInit(ElementNo++);
|
|
if (Init && isa<NoInitExpr>(Init))
|
|
continue;
|
|
|
|
// When emitting a DesignatedInitUpdateExpr, a nested InitListExpr
|
|
// represents additional overwriting of our current constant value, and not
|
|
// a new constant to emit independently.
|
|
if (AllowOverwrite &&
|
|
(Field->getType()->isArrayType() || Field->getType()->isRecordType())) {
|
|
if (auto *SubILE = dyn_cast<InitListExpr>(Init)) {
|
|
CharUnits Offset = CGM.getContext().toCharUnitsFromBits(
|
|
Layout.getFieldOffset(FieldNo));
|
|
if (!EmitDesignatedInitUpdater(Emitter, Builder, StartOffset + Offset,
|
|
Field->getType(), SubILE))
|
|
return false;
|
|
// If we split apart the field's value, try to collapse it down to a
|
|
// single value now.
|
|
Builder.condense(StartOffset + Offset,
|
|
CGM.getTypes().ConvertTypeForMem(Field->getType()));
|
|
continue;
|
|
}
|
|
}
|
|
|
|
llvm::Constant *EltInit =
|
|
Init ? Emitter.tryEmitPrivateForMemory(Init, Field->getType())
|
|
: Emitter.emitNullForMemory(Field->getType());
|
|
if (!EltInit)
|
|
return false;
|
|
|
|
if (!Field->isBitField()) {
|
|
// Handle non-bitfield members.
|
|
if (!AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit,
|
|
AllowOverwrite))
|
|
return false;
|
|
// After emitting a non-empty field with [[no_unique_address]], we may
|
|
// need to overwrite its tail padding.
|
|
if (Field->hasAttr<NoUniqueAddressAttr>())
|
|
AllowOverwrite = true;
|
|
} else {
|
|
// Otherwise we have a bitfield.
|
|
if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
|
|
if (!AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI,
|
|
AllowOverwrite))
|
|
return false;
|
|
} else {
|
|
// We are trying to initialize a bitfield with a non-trivial constant,
|
|
// this must require run-time code.
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
namespace {
|
|
struct BaseInfo {
|
|
BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index)
|
|
: Decl(Decl), Offset(Offset), Index(Index) {
|
|
}
|
|
|
|
const CXXRecordDecl *Decl;
|
|
CharUnits Offset;
|
|
unsigned Index;
|
|
|
|
bool operator<(const BaseInfo &O) const { return Offset < O.Offset; }
|
|
};
|
|
}
|
|
|
|
bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
|
|
bool IsPrimaryBase,
|
|
const CXXRecordDecl *VTableClass,
|
|
CharUnits Offset) {
|
|
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
|
|
|
|
if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
|
|
// Add a vtable pointer, if we need one and it hasn't already been added.
|
|
if (Layout.hasOwnVFPtr()) {
|
|
llvm::Constant *VTableAddressPoint =
|
|
CGM.getCXXABI().getVTableAddressPointForConstExpr(
|
|
BaseSubobject(CD, Offset), VTableClass);
|
|
if (!AppendBytes(Offset, VTableAddressPoint))
|
|
return false;
|
|
}
|
|
|
|
// Accumulate and sort bases, in order to visit them in address order, which
|
|
// may not be the same as declaration order.
|
|
SmallVector<BaseInfo, 8> Bases;
|
|
Bases.reserve(CD->getNumBases());
|
|
unsigned BaseNo = 0;
|
|
for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(),
|
|
BaseEnd = CD->bases_end(); Base != BaseEnd; ++Base, ++BaseNo) {
|
|
assert(!Base->isVirtual() && "should not have virtual bases here");
|
|
const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl();
|
|
CharUnits BaseOffset = Layout.getBaseClassOffset(BD);
|
|
Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo));
|
|
}
|
|
llvm::stable_sort(Bases);
|
|
|
|
for (unsigned I = 0, N = Bases.size(); I != N; ++I) {
|
|
BaseInfo &Base = Bases[I];
|
|
|
|
bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
|
|
Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
|
|
VTableClass, Offset + Base.Offset);
|
|
}
|
|
}
|
|
|
|
unsigned FieldNo = 0;
|
|
uint64_t OffsetBits = CGM.getContext().toBits(Offset);
|
|
|
|
bool AllowOverwrite = false;
|
|
for (RecordDecl::field_iterator Field = RD->field_begin(),
|
|
FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
|
|
// If this is a union, skip all the fields that aren't being initialized.
|
|
if (RD->isUnion() && !declaresSameEntity(Val.getUnionField(), *Field))
|
|
continue;
|
|
|
|
// Don't emit anonymous bitfields or zero-sized fields.
|
|
if (Field->isUnnamedBitfield() || Field->isZeroSize(CGM.getContext()))
|
|
continue;
|
|
|
|
// Emit the value of the initializer.
|
|
const APValue &FieldValue =
|
|
RD->isUnion() ? Val.getUnionValue() : Val.getStructField(FieldNo);
|
|
llvm::Constant *EltInit =
|
|
Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType());
|
|
if (!EltInit)
|
|
return false;
|
|
|
|
if (!Field->isBitField()) {
|
|
// Handle non-bitfield members.
|
|
if (!AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
|
|
EltInit, AllowOverwrite))
|
|
return false;
|
|
// After emitting a non-empty field with [[no_unique_address]], we may
|
|
// need to overwrite its tail padding.
|
|
if (Field->hasAttr<NoUniqueAddressAttr>())
|
|
AllowOverwrite = true;
|
|
} else {
|
|
// Otherwise we have a bitfield.
|
|
if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
|
|
cast<llvm::ConstantInt>(EltInit), AllowOverwrite))
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
llvm::Constant *ConstStructBuilder::Finalize(QualType Type) {
|
|
RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
|
|
llvm::Type *ValTy = CGM.getTypes().ConvertType(Type);
|
|
return Builder.build(ValTy, RD->hasFlexibleArrayMember());
|
|
}
|
|
|
|
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
|
|
InitListExpr *ILE,
|
|
QualType ValTy) {
|
|
ConstantAggregateBuilder Const(Emitter.CGM);
|
|
ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
|
|
|
|
if (!Builder.Build(ILE, /*AllowOverwrite*/false))
|
|
return nullptr;
|
|
|
|
return Builder.Finalize(ValTy);
|
|
}
|
|
|
|
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
|
|
const APValue &Val,
|
|
QualType ValTy) {
|
|
ConstantAggregateBuilder Const(Emitter.CGM);
|
|
ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
|
|
|
|
const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl();
|
|
const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
|
|
if (!Builder.Build(Val, RD, false, CD, CharUnits::Zero()))
|
|
return nullptr;
|
|
|
|
return Builder.Finalize(ValTy);
|
|
}
|
|
|
|
bool ConstStructBuilder::UpdateStruct(ConstantEmitter &Emitter,
|
|
ConstantAggregateBuilder &Const,
|
|
CharUnits Offset, InitListExpr *Updater) {
|
|
return ConstStructBuilder(Emitter, Const, Offset)
|
|
.Build(Updater, /*AllowOverwrite*/ true);
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ConstExprEmitter
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM,
|
|
CodeGenFunction *CGF,
|
|
const CompoundLiteralExpr *E) {
|
|
CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType());
|
|
if (llvm::GlobalVariable *Addr =
|
|
CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
|
|
return ConstantAddress(Addr, Align);
|
|
|
|
LangAS addressSpace = E->getType().getAddressSpace();
|
|
|
|
ConstantEmitter emitter(CGM, CGF);
|
|
llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
|
|
addressSpace, E->getType());
|
|
if (!C) {
|
|
assert(!E->isFileScope() &&
|
|
"file-scope compound literal did not have constant initializer!");
|
|
return ConstantAddress::invalid();
|
|
}
|
|
|
|
auto GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
|
|
CGM.isTypeConstant(E->getType(), true),
|
|
llvm::GlobalValue::InternalLinkage,
|
|
C, ".compoundliteral", nullptr,
|
|
llvm::GlobalVariable::NotThreadLocal,
|
|
CGM.getContext().getTargetAddressSpace(addressSpace));
|
|
emitter.finalize(GV);
|
|
GV->setAlignment(Align.getAsAlign());
|
|
CGM.setAddrOfConstantCompoundLiteral(E, GV);
|
|
return ConstantAddress(GV, Align);
|
|
}
|
|
|
|
static llvm::Constant *
|
|
EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
|
|
llvm::Type *CommonElementType, unsigned ArrayBound,
|
|
SmallVectorImpl<llvm::Constant *> &Elements,
|
|
llvm::Constant *Filler) {
|
|
// Figure out how long the initial prefix of non-zero elements is.
|
|
unsigned NonzeroLength = ArrayBound;
|
|
if (Elements.size() < NonzeroLength && Filler->isNullValue())
|
|
NonzeroLength = Elements.size();
|
|
if (NonzeroLength == Elements.size()) {
|
|
while (NonzeroLength > 0 && Elements[NonzeroLength - 1]->isNullValue())
|
|
--NonzeroLength;
|
|
}
|
|
|
|
if (NonzeroLength == 0)
|
|
return llvm::ConstantAggregateZero::get(DesiredType);
|
|
|
|
// Add a zeroinitializer array filler if we have lots of trailing zeroes.
|
|
unsigned TrailingZeroes = ArrayBound - NonzeroLength;
|
|
if (TrailingZeroes >= 8) {
|
|
assert(Elements.size() >= NonzeroLength &&
|
|
"missing initializer for non-zero element");
|
|
|
|
// If all the elements had the same type up to the trailing zeroes, emit a
|
|
// struct of two arrays (the nonzero data and the zeroinitializer).
|
|
if (CommonElementType && NonzeroLength >= 8) {
|
|
llvm::Constant *Initial = llvm::ConstantArray::get(
|
|
llvm::ArrayType::get(CommonElementType, NonzeroLength),
|
|
makeArrayRef(Elements).take_front(NonzeroLength));
|
|
Elements.resize(2);
|
|
Elements[0] = Initial;
|
|
} else {
|
|
Elements.resize(NonzeroLength + 1);
|
|
}
|
|
|
|
auto *FillerType =
|
|
CommonElementType ? CommonElementType : DesiredType->getElementType();
|
|
FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes);
|
|
Elements.back() = llvm::ConstantAggregateZero::get(FillerType);
|
|
CommonElementType = nullptr;
|
|
} else if (Elements.size() != ArrayBound) {
|
|
// Otherwise pad to the right size with the filler if necessary.
|
|
Elements.resize(ArrayBound, Filler);
|
|
if (Filler->getType() != CommonElementType)
|
|
CommonElementType = nullptr;
|
|
}
|
|
|
|
// If all elements have the same type, just emit an array constant.
|
|
if (CommonElementType)
|
|
return llvm::ConstantArray::get(
|
|
llvm::ArrayType::get(CommonElementType, ArrayBound), Elements);
|
|
|
|
// We have mixed types. Use a packed struct.
|
|
llvm::SmallVector<llvm::Type *, 16> Types;
|
|
Types.reserve(Elements.size());
|
|
for (llvm::Constant *Elt : Elements)
|
|
Types.push_back(Elt->getType());
|
|
llvm::StructType *SType =
|
|
llvm::StructType::get(CGM.getLLVMContext(), Types, true);
|
|
return llvm::ConstantStruct::get(SType, Elements);
|
|
}
|
|
|
|
// This class only needs to handle arrays, structs and unions. Outside C++11
|
|
// mode, we don't currently constant fold those types. All other types are
|
|
// handled by constant folding.
|
|
//
|
|
// Constant folding is currently missing support for a few features supported
|
|
// here: CK_ToUnion, CK_ReinterpretMemberPointer, and DesignatedInitUpdateExpr.
|
|
class ConstExprEmitter :
|
|
public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
|
|
CodeGenModule &CGM;
|
|
ConstantEmitter &Emitter;
|
|
llvm::LLVMContext &VMContext;
|
|
public:
|
|
ConstExprEmitter(ConstantEmitter &emitter)
|
|
: CGM(emitter.CGM), Emitter(emitter), VMContext(CGM.getLLVMContext()) {
|
|
}
|
|
|
|
//===--------------------------------------------------------------------===//
|
|
// Visitor Methods
|
|
//===--------------------------------------------------------------------===//
|
|
|
|
llvm::Constant *VisitStmt(Stmt *S, QualType T) {
|
|
return nullptr;
|
|
}
|
|
|
|
llvm::Constant *VisitConstantExpr(ConstantExpr *CE, QualType T) {
|
|
if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(CE))
|
|
return Result;
|
|
return Visit(CE->getSubExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *VisitParenExpr(ParenExpr *PE, QualType T) {
|
|
return Visit(PE->getSubExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *
|
|
VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE,
|
|
QualType T) {
|
|
return Visit(PE->getReplacement(), T);
|
|
}
|
|
|
|
llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE,
|
|
QualType T) {
|
|
return Visit(GE->getResultExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *VisitChooseExpr(ChooseExpr *CE, QualType T) {
|
|
return Visit(CE->getChosenSubExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E, QualType T) {
|
|
return Visit(E->getInitializer(), T);
|
|
}
|
|
|
|
llvm::Constant *VisitCastExpr(CastExpr *E, QualType destType) {
|
|
if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
|
|
CGM.EmitExplicitCastExprType(ECE, Emitter.CGF);
|
|
Expr *subExpr = E->getSubExpr();
|
|
|
|
switch (E->getCastKind()) {
|
|
case CK_ToUnion: {
|
|
// GCC cast to union extension
|
|
assert(E->getType()->isUnionType() &&
|
|
"Destination type is not union type!");
|
|
|
|
auto field = E->getTargetUnionField();
|
|
|
|
auto C = Emitter.tryEmitPrivateForMemory(subExpr, field->getType());
|
|
if (!C) return nullptr;
|
|
|
|
auto destTy = ConvertType(destType);
|
|
if (C->getType() == destTy) return C;
|
|
|
|
// Build a struct with the union sub-element as the first member,
|
|
// and padded to the appropriate size.
|
|
SmallVector<llvm::Constant*, 2> Elts;
|
|
SmallVector<llvm::Type*, 2> Types;
|
|
Elts.push_back(C);
|
|
Types.push_back(C->getType());
|
|
unsigned CurSize = CGM.getDataLayout().getTypeAllocSize(C->getType());
|
|
unsigned TotalSize = CGM.getDataLayout().getTypeAllocSize(destTy);
|
|
|
|
assert(CurSize <= TotalSize && "Union size mismatch!");
|
|
if (unsigned NumPadBytes = TotalSize - CurSize) {
|
|
llvm::Type *Ty = CGM.Int8Ty;
|
|
if (NumPadBytes > 1)
|
|
Ty = llvm::ArrayType::get(Ty, NumPadBytes);
|
|
|
|
Elts.push_back(llvm::UndefValue::get(Ty));
|
|
Types.push_back(Ty);
|
|
}
|
|
|
|
llvm::StructType *STy = llvm::StructType::get(VMContext, Types, false);
|
|
return llvm::ConstantStruct::get(STy, Elts);
|
|
}
|
|
|
|
case CK_AddressSpaceConversion: {
|
|
auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
|
|
if (!C) return nullptr;
|
|
LangAS destAS = E->getType()->getPointeeType().getAddressSpace();
|
|
LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
|
|
llvm::Type *destTy = ConvertType(E->getType());
|
|
return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS,
|
|
destAS, destTy);
|
|
}
|
|
|
|
case CK_LValueToRValue:
|
|
case CK_AtomicToNonAtomic:
|
|
case CK_NonAtomicToAtomic:
|
|
case CK_NoOp:
|
|
case CK_ConstructorConversion:
|
|
return Visit(subExpr, destType);
|
|
|
|
case CK_IntToOCLSampler:
|
|
llvm_unreachable("global sampler variables are not generated");
|
|
|
|
case CK_Dependent: llvm_unreachable("saw dependent cast!");
|
|
|
|
case CK_BuiltinFnToFnPtr:
|
|
llvm_unreachable("builtin functions are handled elsewhere");
|
|
|
|
case CK_ReinterpretMemberPointer:
|
|
case CK_DerivedToBaseMemberPointer:
|
|
case CK_BaseToDerivedMemberPointer: {
|
|
auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
|
|
if (!C) return nullptr;
|
|
return CGM.getCXXABI().EmitMemberPointerConversion(E, C);
|
|
}
|
|
|
|
// These will never be supported.
|
|
case CK_ObjCObjectLValueCast:
|
|
case CK_ARCProduceObject:
|
|
case CK_ARCConsumeObject:
|
|
case CK_ARCReclaimReturnedObject:
|
|
case CK_ARCExtendBlockObject:
|
|
case CK_CopyAndAutoreleaseBlockObject:
|
|
return nullptr;
|
|
|
|
// These don't need to be handled here because Evaluate knows how to
|
|
// evaluate them in the cases where they can be folded.
|
|
case CK_BitCast:
|
|
case CK_ToVoid:
|
|
case CK_Dynamic:
|
|
case CK_LValueBitCast:
|
|
case CK_LValueToRValueBitCast:
|
|
case CK_NullToMemberPointer:
|
|
case CK_UserDefinedConversion:
|
|
case CK_CPointerToObjCPointerCast:
|
|
case CK_BlockPointerToObjCPointerCast:
|
|
case CK_AnyPointerToBlockPointerCast:
|
|
case CK_ArrayToPointerDecay:
|
|
case CK_FunctionToPointerDecay:
|
|
case CK_BaseToDerived:
|
|
case CK_DerivedToBase:
|
|
case CK_UncheckedDerivedToBase:
|
|
case CK_MemberPointerToBoolean:
|
|
case CK_VectorSplat:
|
|
case CK_FloatingRealToComplex:
|
|
case CK_FloatingComplexToReal:
|
|
case CK_FloatingComplexToBoolean:
|
|
case CK_FloatingComplexCast:
|
|
case CK_FloatingComplexToIntegralComplex:
|
|
case CK_IntegralRealToComplex:
|
|
case CK_IntegralComplexToReal:
|
|
case CK_IntegralComplexToBoolean:
|
|
case CK_IntegralComplexCast:
|
|
case CK_IntegralComplexToFloatingComplex:
|
|
case CK_PointerToIntegral:
|
|
case CK_PointerToBoolean:
|
|
case CK_NullToPointer:
|
|
case CK_IntegralCast:
|
|
case CK_BooleanToSignedIntegral:
|
|
case CK_IntegralToPointer:
|
|
case CK_IntegralToBoolean:
|
|
case CK_IntegralToFloating:
|
|
case CK_FloatingToIntegral:
|
|
case CK_FloatingToBoolean:
|
|
case CK_FloatingCast:
|
|
case CK_FloatingToFixedPoint:
|
|
case CK_FixedPointToFloating:
|
|
case CK_FixedPointCast:
|
|
case CK_FixedPointToBoolean:
|
|
case CK_FixedPointToIntegral:
|
|
case CK_IntegralToFixedPoint:
|
|
case CK_ZeroToOCLOpaqueType:
|
|
return nullptr;
|
|
}
|
|
llvm_unreachable("Invalid CastKind");
|
|
}
|
|
|
|
llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE, QualType T) {
|
|
// No need for a DefaultInitExprScope: we don't handle 'this' in a
|
|
// constant expression.
|
|
return Visit(DIE->getExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *VisitExprWithCleanups(ExprWithCleanups *E, QualType T) {
|
|
return Visit(E->getSubExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
|
|
QualType T) {
|
|
return Visit(E->getSubExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
|
|
auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
|
|
assert(CAT && "can't emit array init for non-constant-bound array");
|
|
unsigned NumInitElements = ILE->getNumInits();
|
|
unsigned NumElements = CAT->getSize().getZExtValue();
|
|
|
|
// Initialising an array requires us to automatically
|
|
// initialise any elements that have not been initialised explicitly
|
|
unsigned NumInitableElts = std::min(NumInitElements, NumElements);
|
|
|
|
QualType EltType = CAT->getElementType();
|
|
|
|
// Initialize remaining array elements.
|
|
llvm::Constant *fillC = nullptr;
|
|
if (Expr *filler = ILE->getArrayFiller()) {
|
|
fillC = Emitter.tryEmitAbstractForMemory(filler, EltType);
|
|
if (!fillC)
|
|
return nullptr;
|
|
}
|
|
|
|
// Copy initializer elements.
|
|
SmallVector<llvm::Constant*, 16> Elts;
|
|
if (fillC && fillC->isNullValue())
|
|
Elts.reserve(NumInitableElts + 1);
|
|
else
|
|
Elts.reserve(NumElements);
|
|
|
|
llvm::Type *CommonElementType = nullptr;
|
|
for (unsigned i = 0; i < NumInitableElts; ++i) {
|
|
Expr *Init = ILE->getInit(i);
|
|
llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType);
|
|
if (!C)
|
|
return nullptr;
|
|
if (i == 0)
|
|
CommonElementType = C->getType();
|
|
else if (C->getType() != CommonElementType)
|
|
CommonElementType = nullptr;
|
|
Elts.push_back(C);
|
|
}
|
|
|
|
llvm::ArrayType *Desired =
|
|
cast<llvm::ArrayType>(CGM.getTypes().ConvertType(ILE->getType()));
|
|
return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
|
|
fillC);
|
|
}
|
|
|
|
llvm::Constant *EmitRecordInitialization(InitListExpr *ILE, QualType T) {
|
|
return ConstStructBuilder::BuildStruct(Emitter, ILE, T);
|
|
}
|
|
|
|
llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E,
|
|
QualType T) {
|
|
return CGM.EmitNullConstant(T);
|
|
}
|
|
|
|
llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) {
|
|
if (ILE->isTransparent())
|
|
return Visit(ILE->getInit(0), T);
|
|
|
|
if (ILE->getType()->isArrayType())
|
|
return EmitArrayInitialization(ILE, T);
|
|
|
|
if (ILE->getType()->isRecordType())
|
|
return EmitRecordInitialization(ILE, T);
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
|
|
QualType destType) {
|
|
auto C = Visit(E->getBase(), destType);
|
|
if (!C)
|
|
return nullptr;
|
|
|
|
ConstantAggregateBuilder Const(CGM);
|
|
Const.add(C, CharUnits::Zero(), false);
|
|
|
|
if (!EmitDesignatedInitUpdater(Emitter, Const, CharUnits::Zero(), destType,
|
|
E->getUpdater()))
|
|
return nullptr;
|
|
|
|
llvm::Type *ValTy = CGM.getTypes().ConvertType(destType);
|
|
bool HasFlexibleArray = false;
|
|
if (auto *RT = destType->getAs<RecordType>())
|
|
HasFlexibleArray = RT->getDecl()->hasFlexibleArrayMember();
|
|
return Const.build(ValTy, HasFlexibleArray);
|
|
}
|
|
|
|
llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
|
|
if (!E->getConstructor()->isTrivial())
|
|
return nullptr;
|
|
|
|
// Only default and copy/move constructors can be trivial.
|
|
if (E->getNumArgs()) {
|
|
assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument");
|
|
assert(E->getConstructor()->isCopyOrMoveConstructor() &&
|
|
"trivial ctor has argument but isn't a copy/move ctor");
|
|
|
|
Expr *Arg = E->getArg(0);
|
|
assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&
|
|
"argument to copy ctor is of wrong type");
|
|
|
|
return Visit(Arg, Ty);
|
|
}
|
|
|
|
return CGM.EmitNullConstant(Ty);
|
|
}
|
|
|
|
llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) {
|
|
// This is a string literal initializing an array in an initializer.
|
|
return CGM.GetConstantArrayFromStringLiteral(E);
|
|
}
|
|
|
|
llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) {
|
|
// This must be an @encode initializing an array in a static initializer.
|
|
// Don't emit it as the address of the string, emit the string data itself
|
|
// as an inline array.
|
|
std::string Str;
|
|
CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
|
|
const ConstantArrayType *CAT = CGM.getContext().getAsConstantArrayType(T);
|
|
|
|
// Resize the string to the right size, adding zeros at the end, or
|
|
// truncating as needed.
|
|
Str.resize(CAT->getSize().getZExtValue(), '\0');
|
|
return llvm::ConstantDataArray::getString(VMContext, Str, false);
|
|
}
|
|
|
|
llvm::Constant *VisitUnaryExtension(const UnaryOperator *E, QualType T) {
|
|
return Visit(E->getSubExpr(), T);
|
|
}
|
|
|
|
// Utility methods
|
|
llvm::Type *ConvertType(QualType T) {
|
|
return CGM.getTypes().ConvertType(T);
|
|
}
|
|
};
|
|
|
|
} // end anonymous namespace.
|
|
|
|
llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
|
|
AbstractState saved) {
|
|
Abstract = saved.OldValue;
|
|
|
|
assert(saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&
|
|
"created a placeholder while doing an abstract emission?");
|
|
|
|
// No validation necessary for now.
|
|
// No cleanup to do for now.
|
|
return C;
|
|
}
|
|
|
|
llvm::Constant *
|
|
ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) {
|
|
auto state = pushAbstract();
|
|
auto C = tryEmitPrivateForVarInit(D);
|
|
return validateAndPopAbstract(C, state);
|
|
}
|
|
|
|
llvm::Constant *
|
|
ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) {
|
|
auto state = pushAbstract();
|
|
auto C = tryEmitPrivate(E, destType);
|
|
return validateAndPopAbstract(C, state);
|
|
}
|
|
|
|
llvm::Constant *
|
|
ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) {
|
|
auto state = pushAbstract();
|
|
auto C = tryEmitPrivate(value, destType);
|
|
return validateAndPopAbstract(C, state);
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitConstantExpr(const ConstantExpr *CE) {
|
|
if (!CE->hasAPValueResult())
|
|
return nullptr;
|
|
const Expr *Inner = CE->getSubExpr()->IgnoreImplicit();
|
|
QualType RetType;
|
|
if (auto *Call = dyn_cast<CallExpr>(Inner))
|
|
RetType = Call->getCallReturnType(CGF->getContext());
|
|
else if (auto *Ctor = dyn_cast<CXXConstructExpr>(Inner))
|
|
RetType = Ctor->getType();
|
|
llvm::Constant *Res =
|
|
emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(), RetType);
|
|
return Res;
|
|
}
|
|
|
|
llvm::Constant *
|
|
ConstantEmitter::emitAbstract(const Expr *E, QualType destType) {
|
|
auto state = pushAbstract();
|
|
auto C = tryEmitPrivate(E, destType);
|
|
C = validateAndPopAbstract(C, state);
|
|
if (!C) {
|
|
CGM.Error(E->getExprLoc(),
|
|
"internal error: could not emit constant value \"abstractly\"");
|
|
C = CGM.EmitNullConstant(destType);
|
|
}
|
|
return C;
|
|
}
|
|
|
|
llvm::Constant *
|
|
ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value,
|
|
QualType destType) {
|
|
auto state = pushAbstract();
|
|
auto C = tryEmitPrivate(value, destType);
|
|
C = validateAndPopAbstract(C, state);
|
|
if (!C) {
|
|
CGM.Error(loc,
|
|
"internal error: could not emit constant value \"abstractly\"");
|
|
C = CGM.EmitNullConstant(destType);
|
|
}
|
|
return C;
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
|
|
initializeNonAbstract(D.getType().getAddressSpace());
|
|
return markIfFailed(tryEmitPrivateForVarInit(D));
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
|
|
LangAS destAddrSpace,
|
|
QualType destType) {
|
|
initializeNonAbstract(destAddrSpace);
|
|
return markIfFailed(tryEmitPrivateForMemory(E, destType));
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value,
|
|
LangAS destAddrSpace,
|
|
QualType destType) {
|
|
initializeNonAbstract(destAddrSpace);
|
|
auto C = tryEmitPrivateForMemory(value, destType);
|
|
assert(C && "couldn't emit constant value non-abstractly?");
|
|
return C;
|
|
}
|
|
|
|
llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() {
|
|
assert(!Abstract && "cannot get current address for abstract constant");
|
|
|
|
|
|
|
|
// Make an obviously ill-formed global that should blow up compilation
|
|
// if it survives.
|
|
auto global = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, true,
|
|
llvm::GlobalValue::PrivateLinkage,
|
|
/*init*/ nullptr,
|
|
/*name*/ "",
|
|
/*before*/ nullptr,
|
|
llvm::GlobalVariable::NotThreadLocal,
|
|
CGM.getContext().getTargetAddressSpace(DestAddressSpace));
|
|
|
|
PlaceholderAddresses.push_back(std::make_pair(nullptr, global));
|
|
|
|
return global;
|
|
}
|
|
|
|
void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal,
|
|
llvm::GlobalValue *placeholder) {
|
|
assert(!PlaceholderAddresses.empty());
|
|
assert(PlaceholderAddresses.back().first == nullptr);
|
|
assert(PlaceholderAddresses.back().second == placeholder);
|
|
PlaceholderAddresses.back().first = signal;
|
|
}
|
|
|
|
namespace {
|
|
struct ReplacePlaceholders {
|
|
CodeGenModule &CGM;
|
|
|
|
/// The base address of the global.
|
|
llvm::Constant *Base;
|
|
llvm::Type *BaseValueTy = nullptr;
|
|
|
|
/// The placeholder addresses that were registered during emission.
|
|
llvm::DenseMap<llvm::Constant*, llvm::GlobalVariable*> PlaceholderAddresses;
|
|
|
|
/// The locations of the placeholder signals.
|
|
llvm::DenseMap<llvm::GlobalVariable*, llvm::Constant*> Locations;
|
|
|
|
/// The current index stack. We use a simple unsigned stack because
|
|
/// we assume that placeholders will be relatively sparse in the
|
|
/// initializer, but we cache the index values we find just in case.
|
|
llvm::SmallVector<unsigned, 8> Indices;
|
|
llvm::SmallVector<llvm::Constant*, 8> IndexValues;
|
|
|
|
ReplacePlaceholders(CodeGenModule &CGM, llvm::Constant *base,
|
|
ArrayRef<std::pair<llvm::Constant*,
|
|
llvm::GlobalVariable*>> addresses)
|
|
: CGM(CGM), Base(base),
|
|
PlaceholderAddresses(addresses.begin(), addresses.end()) {
|
|
}
|
|
|
|
void replaceInInitializer(llvm::Constant *init) {
|
|
// Remember the type of the top-most initializer.
|
|
BaseValueTy = init->getType();
|
|
|
|
// Initialize the stack.
|
|
Indices.push_back(0);
|
|
IndexValues.push_back(nullptr);
|
|
|
|
// Recurse into the initializer.
|
|
findLocations(init);
|
|
|
|
// Check invariants.
|
|
assert(IndexValues.size() == Indices.size() && "mismatch");
|
|
assert(Indices.size() == 1 && "didn't pop all indices");
|
|
|
|
// Do the replacement; this basically invalidates 'init'.
|
|
assert(Locations.size() == PlaceholderAddresses.size() &&
|
|
"missed a placeholder?");
|
|
|
|
// We're iterating over a hashtable, so this would be a source of
|
|
// non-determinism in compiler output *except* that we're just
|
|
// messing around with llvm::Constant structures, which never itself
|
|
// does anything that should be visible in compiler output.
|
|
for (auto &entry : Locations) {
|
|
assert(entry.first->getParent() == nullptr && "not a placeholder!");
|
|
entry.first->replaceAllUsesWith(entry.second);
|
|
entry.first->eraseFromParent();
|
|
}
|
|
}
|
|
|
|
private:
|
|
void findLocations(llvm::Constant *init) {
|
|
// Recurse into aggregates.
|
|
if (auto agg = dyn_cast<llvm::ConstantAggregate>(init)) {
|
|
for (unsigned i = 0, e = agg->getNumOperands(); i != e; ++i) {
|
|
Indices.push_back(i);
|
|
IndexValues.push_back(nullptr);
|
|
|
|
findLocations(agg->getOperand(i));
|
|
|
|
IndexValues.pop_back();
|
|
Indices.pop_back();
|
|
}
|
|
return;
|
|
}
|
|
|
|
// Otherwise, check for registered constants.
|
|
while (true) {
|
|
auto it = PlaceholderAddresses.find(init);
|
|
if (it != PlaceholderAddresses.end()) {
|
|
setLocation(it->second);
|
|
break;
|
|
}
|
|
|
|
// Look through bitcasts or other expressions.
|
|
if (auto expr = dyn_cast<llvm::ConstantExpr>(init)) {
|
|
init = expr->getOperand(0);
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void setLocation(llvm::GlobalVariable *placeholder) {
|
|
assert(Locations.find(placeholder) == Locations.end() &&
|
|
"already found location for placeholder!");
|
|
|
|
// Lazily fill in IndexValues with the values from Indices.
|
|
// We do this in reverse because we should always have a strict
|
|
// prefix of indices from the start.
|
|
assert(Indices.size() == IndexValues.size());
|
|
for (size_t i = Indices.size() - 1; i != size_t(-1); --i) {
|
|
if (IndexValues[i]) {
|
|
#ifndef NDEBUG
|
|
for (size_t j = 0; j != i + 1; ++j) {
|
|
assert(IndexValues[j] &&
|
|
isa<llvm::ConstantInt>(IndexValues[j]) &&
|
|
cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue()
|
|
== Indices[j]);
|
|
}
|
|
#endif
|
|
break;
|
|
}
|
|
|
|
IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]);
|
|
}
|
|
|
|
// Form a GEP and then bitcast to the placeholder type so that the
|
|
// replacement will succeed.
|
|
llvm::Constant *location =
|
|
llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy,
|
|
Base, IndexValues);
|
|
location = llvm::ConstantExpr::getBitCast(location,
|
|
placeholder->getType());
|
|
|
|
Locations.insert({placeholder, location});
|
|
}
|
|
};
|
|
}
|
|
|
|
void ConstantEmitter::finalize(llvm::GlobalVariable *global) {
|
|
assert(InitializedNonAbstract &&
|
|
"finalizing emitter that was used for abstract emission?");
|
|
assert(!Finalized && "finalizing emitter multiple times");
|
|
assert(global->getInitializer());
|
|
|
|
// Note that we might also be Failed.
|
|
Finalized = true;
|
|
|
|
if (!PlaceholderAddresses.empty()) {
|
|
ReplacePlaceholders(CGM, global, PlaceholderAddresses)
|
|
.replaceInInitializer(global->getInitializer());
|
|
PlaceholderAddresses.clear(); // satisfy
|
|
}
|
|
}
|
|
|
|
ConstantEmitter::~ConstantEmitter() {
|
|
assert((!InitializedNonAbstract || Finalized || Failed) &&
|
|
"not finalized after being initialized for non-abstract emission");
|
|
assert(PlaceholderAddresses.empty() && "unhandled placeholders");
|
|
}
|
|
|
|
static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) {
|
|
if (auto AT = type->getAs<AtomicType>()) {
|
|
return CGM.getContext().getQualifiedType(AT->getValueType(),
|
|
type.getQualifiers());
|
|
}
|
|
return type;
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) {
|
|
// Make a quick check if variable can be default NULL initialized
|
|
// and avoid going through rest of code which may do, for c++11,
|
|
// initialization of memory to all NULLs.
|
|
if (!D.hasLocalStorage()) {
|
|
QualType Ty = CGM.getContext().getBaseElementType(D.getType());
|
|
if (Ty->isRecordType())
|
|
if (const CXXConstructExpr *E =
|
|
dyn_cast_or_null<CXXConstructExpr>(D.getInit())) {
|
|
const CXXConstructorDecl *CD = E->getConstructor();
|
|
if (CD->isTrivial() && CD->isDefaultConstructor())
|
|
return CGM.EmitNullConstant(D.getType());
|
|
}
|
|
}
|
|
InConstantContext = D.hasConstantInitialization();
|
|
|
|
QualType destType = D.getType();
|
|
|
|
// Try to emit the initializer. Note that this can allow some things that
|
|
// are not allowed by tryEmitPrivateForMemory alone.
|
|
if (auto value = D.evaluateValue()) {
|
|
return tryEmitPrivateForMemory(*value, destType);
|
|
}
|
|
|
|
// FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
|
|
// reference is a constant expression, and the reference binds to a temporary,
|
|
// then constant initialization is performed. ConstExprEmitter will
|
|
// incorrectly emit a prvalue constant in this case, and the calling code
|
|
// interprets that as the (pointer) value of the reference, rather than the
|
|
// desired value of the referee.
|
|
if (destType->isReferenceType())
|
|
return nullptr;
|
|
|
|
const Expr *E = D.getInit();
|
|
assert(E && "No initializer to emit");
|
|
|
|
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
|
|
auto C =
|
|
ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
|
|
return (C ? emitForMemory(C, destType) : nullptr);
|
|
}
|
|
|
|
llvm::Constant *
|
|
ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) {
|
|
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
|
|
auto C = tryEmitAbstract(E, nonMemoryDestType);
|
|
return (C ? emitForMemory(C, destType) : nullptr);
|
|
}
|
|
|
|
llvm::Constant *
|
|
ConstantEmitter::tryEmitAbstractForMemory(const APValue &value,
|
|
QualType destType) {
|
|
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
|
|
auto C = tryEmitAbstract(value, nonMemoryDestType);
|
|
return (C ? emitForMemory(C, destType) : nullptr);
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const Expr *E,
|
|
QualType destType) {
|
|
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
|
|
llvm::Constant *C = tryEmitPrivate(E, nonMemoryDestType);
|
|
return (C ? emitForMemory(C, destType) : nullptr);
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value,
|
|
QualType destType) {
|
|
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
|
|
auto C = tryEmitPrivate(value, nonMemoryDestType);
|
|
return (C ? emitForMemory(C, destType) : nullptr);
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::emitForMemory(CodeGenModule &CGM,
|
|
llvm::Constant *C,
|
|
QualType destType) {
|
|
// For an _Atomic-qualified constant, we may need to add tail padding.
|
|
if (auto AT = destType->getAs<AtomicType>()) {
|
|
QualType destValueType = AT->getValueType();
|
|
C = emitForMemory(CGM, C, destValueType);
|
|
|
|
uint64_t innerSize = CGM.getContext().getTypeSize(destValueType);
|
|
uint64_t outerSize = CGM.getContext().getTypeSize(destType);
|
|
if (innerSize == outerSize)
|
|
return C;
|
|
|
|
assert(innerSize < outerSize && "emitted over-large constant for atomic");
|
|
llvm::Constant *elts[] = {
|
|
C,
|
|
llvm::ConstantAggregateZero::get(
|
|
llvm::ArrayType::get(CGM.Int8Ty, (outerSize - innerSize) / 8))
|
|
};
|
|
return llvm::ConstantStruct::getAnon(elts);
|
|
}
|
|
|
|
// Zero-extend bool.
|
|
if (C->getType()->isIntegerTy(1)) {
|
|
llvm::Type *boolTy = CGM.getTypes().ConvertTypeForMem(destType);
|
|
return llvm::ConstantExpr::getZExt(C, boolTy);
|
|
}
|
|
|
|
return C;
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E,
|
|
QualType destType) {
|
|
Expr::EvalResult Result;
|
|
|
|
bool Success = false;
|
|
|
|
if (destType->isReferenceType())
|
|
Success = E->EvaluateAsLValue(Result, CGM.getContext());
|
|
else
|
|
Success = E->EvaluateAsRValue(Result, CGM.getContext(), InConstantContext);
|
|
|
|
llvm::Constant *C;
|
|
if (Success && !Result.HasSideEffects)
|
|
C = tryEmitPrivate(Result.Val, destType);
|
|
else
|
|
C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType);
|
|
|
|
return C;
|
|
}
|
|
|
|
llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
|
|
return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
|
|
}
|
|
|
|
namespace {
|
|
/// A struct which can be used to peephole certain kinds of finalization
|
|
/// that normally happen during l-value emission.
|
|
struct ConstantLValue {
|
|
llvm::Constant *Value;
|
|
bool HasOffsetApplied;
|
|
|
|
/*implicit*/ ConstantLValue(llvm::Constant *value,
|
|
bool hasOffsetApplied = false)
|
|
: Value(value), HasOffsetApplied(hasOffsetApplied) {}
|
|
|
|
/*implicit*/ ConstantLValue(ConstantAddress address)
|
|
: ConstantLValue(address.getPointer()) {}
|
|
};
|
|
|
|
/// A helper class for emitting constant l-values.
|
|
class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter,
|
|
ConstantLValue> {
|
|
CodeGenModule &CGM;
|
|
ConstantEmitter &Emitter;
|
|
const APValue &Value;
|
|
QualType DestType;
|
|
|
|
// Befriend StmtVisitorBase so that we don't have to expose Visit*.
|
|
friend StmtVisitorBase;
|
|
|
|
public:
|
|
ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
|
|
QualType destType)
|
|
: CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}
|
|
|
|
llvm::Constant *tryEmit();
|
|
|
|
private:
|
|
llvm::Constant *tryEmitAbsolute(llvm::Type *destTy);
|
|
ConstantLValue tryEmitBase(const APValue::LValueBase &base);
|
|
|
|
ConstantLValue VisitStmt(const Stmt *S) { return nullptr; }
|
|
ConstantLValue VisitConstantExpr(const ConstantExpr *E);
|
|
ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
|
|
ConstantLValue VisitStringLiteral(const StringLiteral *E);
|
|
ConstantLValue VisitObjCBoxedExpr(const ObjCBoxedExpr *E);
|
|
ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
|
|
ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E);
|
|
ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E);
|
|
ConstantLValue VisitAddrLabelExpr(const AddrLabelExpr *E);
|
|
ConstantLValue VisitCallExpr(const CallExpr *E);
|
|
ConstantLValue VisitBlockExpr(const BlockExpr *E);
|
|
ConstantLValue VisitCXXTypeidExpr(const CXXTypeidExpr *E);
|
|
ConstantLValue VisitMaterializeTemporaryExpr(
|
|
const MaterializeTemporaryExpr *E);
|
|
|
|
bool hasNonZeroOffset() const {
|
|
return !Value.getLValueOffset().isZero();
|
|
}
|
|
|
|
/// Return the value offset.
|
|
llvm::Constant *getOffset() {
|
|
return llvm::ConstantInt::get(CGM.Int64Ty,
|
|
Value.getLValueOffset().getQuantity());
|
|
}
|
|
|
|
/// Apply the value offset to the given constant.
|
|
llvm::Constant *applyOffset(llvm::Constant *C) {
|
|
if (!hasNonZeroOffset())
|
|
return C;
|
|
|
|
llvm::Type *origPtrTy = C->getType();
|
|
unsigned AS = origPtrTy->getPointerAddressSpace();
|
|
llvm::Type *charPtrTy = CGM.Int8Ty->getPointerTo(AS);
|
|
C = llvm::ConstantExpr::getBitCast(C, charPtrTy);
|
|
C = llvm::ConstantExpr::getGetElementPtr(CGM.Int8Ty, C, getOffset());
|
|
C = llvm::ConstantExpr::getPointerCast(C, origPtrTy);
|
|
return C;
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
llvm::Constant *ConstantLValueEmitter::tryEmit() {
|
|
const APValue::LValueBase &base = Value.getLValueBase();
|
|
|
|
// The destination type should be a pointer or reference
|
|
// type, but it might also be a cast thereof.
|
|
//
|
|
// FIXME: the chain of casts required should be reflected in the APValue.
|
|
// We need this in order to correctly handle things like a ptrtoint of a
|
|
// non-zero null pointer and addrspace casts that aren't trivially
|
|
// represented in LLVM IR.
|
|
auto destTy = CGM.getTypes().ConvertTypeForMem(DestType);
|
|
assert(isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy));
|
|
|
|
// If there's no base at all, this is a null or absolute pointer,
|
|
// possibly cast back to an integer type.
|
|
if (!base) {
|
|
return tryEmitAbsolute(destTy);
|
|
}
|
|
|
|
// Otherwise, try to emit the base.
|
|
ConstantLValue result = tryEmitBase(base);
|
|
|
|
// If that failed, we're done.
|
|
llvm::Constant *value = result.Value;
|
|
if (!value) return nullptr;
|
|
|
|
// Apply the offset if necessary and not already done.
|
|
if (!result.HasOffsetApplied) {
|
|
value = applyOffset(value);
|
|
}
|
|
|
|
// Convert to the appropriate type; this could be an lvalue for
|
|
// an integer. FIXME: performAddrSpaceCast
|
|
if (isa<llvm::PointerType>(destTy))
|
|
return llvm::ConstantExpr::getPointerCast(value, destTy);
|
|
|
|
return llvm::ConstantExpr::getPtrToInt(value, destTy);
|
|
}
|
|
|
|
/// Try to emit an absolute l-value, such as a null pointer or an integer
|
|
/// bitcast to pointer type.
|
|
llvm::Constant *
|
|
ConstantLValueEmitter::tryEmitAbsolute(llvm::Type *destTy) {
|
|
// If we're producing a pointer, this is easy.
|
|
auto destPtrTy = cast<llvm::PointerType>(destTy);
|
|
if (Value.isNullPointer()) {
|
|
// FIXME: integer offsets from non-zero null pointers.
|
|
return CGM.getNullPointer(destPtrTy, DestType);
|
|
}
|
|
|
|
// Convert the integer to a pointer-sized integer before converting it
|
|
// to a pointer.
|
|
// FIXME: signedness depends on the original integer type.
|
|
auto intptrTy = CGM.getDataLayout().getIntPtrType(destPtrTy);
|
|
llvm::Constant *C;
|
|
C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy,
|
|
/*isSigned*/ false);
|
|
C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy);
|
|
return C;
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
|
|
// Handle values.
|
|
if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
|
|
// The constant always points to the canonical declaration. We want to look
|
|
// at properties of the most recent declaration at the point of emission.
|
|
D = cast<ValueDecl>(D->getMostRecentDecl());
|
|
|
|
if (D->hasAttr<WeakRefAttr>())
|
|
return CGM.GetWeakRefReference(D).getPointer();
|
|
|
|
if (auto FD = dyn_cast<FunctionDecl>(D))
|
|
return CGM.GetAddrOfFunction(FD);
|
|
|
|
if (auto VD = dyn_cast<VarDecl>(D)) {
|
|
// We can never refer to a variable with local storage.
|
|
if (!VD->hasLocalStorage()) {
|
|
if (VD->isFileVarDecl() || VD->hasExternalStorage())
|
|
return CGM.GetAddrOfGlobalVar(VD);
|
|
|
|
if (VD->isLocalVarDecl()) {
|
|
return CGM.getOrCreateStaticVarDecl(
|
|
*VD, CGM.getLLVMLinkageVarDefinition(VD, /*IsConstant=*/false));
|
|
}
|
|
}
|
|
}
|
|
|
|
if (auto *GD = dyn_cast<MSGuidDecl>(D))
|
|
return CGM.GetAddrOfMSGuidDecl(GD);
|
|
|
|
if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(D))
|
|
return CGM.GetAddrOfTemplateParamObject(TPO);
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
// Handle typeid(T).
|
|
if (TypeInfoLValue TI = base.dyn_cast<TypeInfoLValue>()) {
|
|
llvm::Type *StdTypeInfoPtrTy =
|
|
CGM.getTypes().ConvertType(base.getTypeInfoType())->getPointerTo();
|
|
llvm::Constant *TypeInfo =
|
|
CGM.GetAddrOfRTTIDescriptor(QualType(TI.getType(), 0));
|
|
if (TypeInfo->getType() != StdTypeInfoPtrTy)
|
|
TypeInfo = llvm::ConstantExpr::getBitCast(TypeInfo, StdTypeInfoPtrTy);
|
|
return TypeInfo;
|
|
}
|
|
|
|
// Otherwise, it must be an expression.
|
|
return Visit(base.get<const Expr*>());
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitConstantExpr(const ConstantExpr *E) {
|
|
if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(E))
|
|
return Result;
|
|
return Visit(E->getSubExpr());
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
|
|
return tryEmitGlobalCompoundLiteral(CGM, Emitter.CGF, E);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) {
|
|
return CGM.GetAddrOfConstantStringFromLiteral(E);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
|
|
return CGM.GetAddrOfConstantStringFromObjCEncode(E);
|
|
}
|
|
|
|
static ConstantLValue emitConstantObjCStringLiteral(const StringLiteral *S,
|
|
QualType T,
|
|
CodeGenModule &CGM) {
|
|
auto C = CGM.getObjCRuntime().GenerateConstantString(S);
|
|
return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(T));
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
|
|
return emitConstantObjCStringLiteral(E->getString(), E->getType(), CGM);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
|
|
assert(E->isExpressibleAsConstantInitializer() &&
|
|
"this boxed expression can't be emitted as a compile-time constant");
|
|
auto *SL = cast<StringLiteral>(E->getSubExpr()->IgnoreParenCasts());
|
|
return emitConstantObjCStringLiteral(SL, E->getType(), CGM);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
|
|
return CGM.GetAddrOfConstantStringFromLiteral(E->getFunctionName());
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
|
|
assert(Emitter.CGF && "Invalid address of label expression outside function");
|
|
llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
|
|
Ptr = llvm::ConstantExpr::getBitCast(Ptr,
|
|
CGM.getTypes().ConvertType(E->getType()));
|
|
return Ptr;
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) {
|
|
unsigned builtin = E->getBuiltinCallee();
|
|
if (builtin != Builtin::BI__builtin___CFStringMakeConstantString &&
|
|
builtin != Builtin::BI__builtin___NSStringMakeConstantString)
|
|
return nullptr;
|
|
|
|
auto literal = cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts());
|
|
if (builtin == Builtin::BI__builtin___NSStringMakeConstantString) {
|
|
return CGM.getObjCRuntime().GenerateConstantString(literal);
|
|
} else {
|
|
// FIXME: need to deal with UCN conversion issues.
|
|
return CGM.GetAddrOfConstantCFString(literal);
|
|
}
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) {
|
|
StringRef functionName;
|
|
if (auto CGF = Emitter.CGF)
|
|
functionName = CGF->CurFn->getName();
|
|
else
|
|
functionName = "global";
|
|
|
|
return CGM.GetAddrOfGlobalBlock(E, functionName);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
|
|
QualType T;
|
|
if (E->isTypeOperand())
|
|
T = E->getTypeOperand(CGM.getContext());
|
|
else
|
|
T = E->getExprOperand()->getType();
|
|
return CGM.GetAddrOfRTTIDescriptor(T);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
|
|
const MaterializeTemporaryExpr *E) {
|
|
assert(E->getStorageDuration() == SD_Static);
|
|
SmallVector<const Expr *, 2> CommaLHSs;
|
|
SmallVector<SubobjectAdjustment, 2> Adjustments;
|
|
const Expr *Inner =
|
|
E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
|
|
return CGM.GetAddrOfGlobalTemporary(E, Inner);
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
|
|
QualType DestType) {
|
|
switch (Value.getKind()) {
|
|
case APValue::None:
|
|
case APValue::Indeterminate:
|
|
// Out-of-lifetime and indeterminate values can be modeled as 'undef'.
|
|
return llvm::UndefValue::get(CGM.getTypes().ConvertType(DestType));
|
|
case APValue::LValue:
|
|
return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
|
|
case APValue::Int:
|
|
return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
|
|
case APValue::FixedPoint:
|
|
return llvm::ConstantInt::get(CGM.getLLVMContext(),
|
|
Value.getFixedPoint().getValue());
|
|
case APValue::ComplexInt: {
|
|
llvm::Constant *Complex[2];
|
|
|
|
Complex[0] = llvm::ConstantInt::get(CGM.getLLVMContext(),
|
|
Value.getComplexIntReal());
|
|
Complex[1] = llvm::ConstantInt::get(CGM.getLLVMContext(),
|
|
Value.getComplexIntImag());
|
|
|
|
// FIXME: the target may want to specify that this is packed.
|
|
llvm::StructType *STy =
|
|
llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
|
|
return llvm::ConstantStruct::get(STy, Complex);
|
|
}
|
|
case APValue::Float: {
|
|
const llvm::APFloat &Init = Value.getFloat();
|
|
if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf() &&
|
|
!CGM.getContext().getLangOpts().NativeHalfType &&
|
|
CGM.getContext().getTargetInfo().useFP16ConversionIntrinsics())
|
|
return llvm::ConstantInt::get(CGM.getLLVMContext(),
|
|
Init.bitcastToAPInt());
|
|
else
|
|
return llvm::ConstantFP::get(CGM.getLLVMContext(), Init);
|
|
}
|
|
case APValue::ComplexFloat: {
|
|
llvm::Constant *Complex[2];
|
|
|
|
Complex[0] = llvm::ConstantFP::get(CGM.getLLVMContext(),
|
|
Value.getComplexFloatReal());
|
|
Complex[1] = llvm::ConstantFP::get(CGM.getLLVMContext(),
|
|
Value.getComplexFloatImag());
|
|
|
|
// FIXME: the target may want to specify that this is packed.
|
|
llvm::StructType *STy =
|
|
llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
|
|
return llvm::ConstantStruct::get(STy, Complex);
|
|
}
|
|
case APValue::Vector: {
|
|
unsigned NumElts = Value.getVectorLength();
|
|
SmallVector<llvm::Constant *, 4> Inits(NumElts);
|
|
|
|
for (unsigned I = 0; I != NumElts; ++I) {
|
|
const APValue &Elt = Value.getVectorElt(I);
|
|
if (Elt.isInt())
|
|
Inits[I] = llvm::ConstantInt::get(CGM.getLLVMContext(), Elt.getInt());
|
|
else if (Elt.isFloat())
|
|
Inits[I] = llvm::ConstantFP::get(CGM.getLLVMContext(), Elt.getFloat());
|
|
else
|
|
llvm_unreachable("unsupported vector element type");
|
|
}
|
|
return llvm::ConstantVector::get(Inits);
|
|
}
|
|
case APValue::AddrLabelDiff: {
|
|
const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS();
|
|
const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS();
|
|
llvm::Constant *LHS = tryEmitPrivate(LHSExpr, LHSExpr->getType());
|
|
llvm::Constant *RHS = tryEmitPrivate(RHSExpr, RHSExpr->getType());
|
|
if (!LHS || !RHS) return nullptr;
|
|
|
|
// Compute difference
|
|
llvm::Type *ResultType = CGM.getTypes().ConvertType(DestType);
|
|
LHS = llvm::ConstantExpr::getPtrToInt(LHS, CGM.IntPtrTy);
|
|
RHS = llvm::ConstantExpr::getPtrToInt(RHS, CGM.IntPtrTy);
|
|
llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
|
|
|
|
// LLVM is a bit sensitive about the exact format of the
|
|
// address-of-label difference; make sure to truncate after
|
|
// the subtraction.
|
|
return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);
|
|
}
|
|
case APValue::Struct:
|
|
case APValue::Union:
|
|
return ConstStructBuilder::BuildStruct(*this, Value, DestType);
|
|
case APValue::Array: {
|
|
const ArrayType *ArrayTy = CGM.getContext().getAsArrayType(DestType);
|
|
unsigned NumElements = Value.getArraySize();
|
|
unsigned NumInitElts = Value.getArrayInitializedElts();
|
|
|
|
// Emit array filler, if there is one.
|
|
llvm::Constant *Filler = nullptr;
|
|
if (Value.hasArrayFiller()) {
|
|
Filler = tryEmitAbstractForMemory(Value.getArrayFiller(),
|
|
ArrayTy->getElementType());
|
|
if (!Filler)
|
|
return nullptr;
|
|
}
|
|
|
|
// Emit initializer elements.
|
|
SmallVector<llvm::Constant*, 16> Elts;
|
|
if (Filler && Filler->isNullValue())
|
|
Elts.reserve(NumInitElts + 1);
|
|
else
|
|
Elts.reserve(NumElements);
|
|
|
|
llvm::Type *CommonElementType = nullptr;
|
|
for (unsigned I = 0; I < NumInitElts; ++I) {
|
|
llvm::Constant *C = tryEmitPrivateForMemory(
|
|
Value.getArrayInitializedElt(I), ArrayTy->getElementType());
|
|
if (!C) return nullptr;
|
|
|
|
if (I == 0)
|
|
CommonElementType = C->getType();
|
|
else if (C->getType() != CommonElementType)
|
|
CommonElementType = nullptr;
|
|
Elts.push_back(C);
|
|
}
|
|
|
|
llvm::ArrayType *Desired =
|
|
cast<llvm::ArrayType>(CGM.getTypes().ConvertType(DestType));
|
|
return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
|
|
Filler);
|
|
}
|
|
case APValue::MemberPointer:
|
|
return CGM.getCXXABI().EmitMemberPointer(Value, DestType);
|
|
}
|
|
llvm_unreachable("Unknown APValue kind");
|
|
}
|
|
|
|
llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted(
|
|
const CompoundLiteralExpr *E) {
|
|
return EmittedCompoundLiterals.lookup(E);
|
|
}
|
|
|
|
void CodeGenModule::setAddrOfConstantCompoundLiteral(
|
|
const CompoundLiteralExpr *CLE, llvm::GlobalVariable *GV) {
|
|
bool Ok = EmittedCompoundLiterals.insert(std::make_pair(CLE, GV)).second;
|
|
(void)Ok;
|
|
assert(Ok && "CLE has already been emitted!");
|
|
}
|
|
|
|
ConstantAddress
|
|
CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) {
|
|
assert(E->isFileScope() && "not a file-scope compound literal expr");
|
|
return tryEmitGlobalCompoundLiteral(*this, nullptr, E);
|
|
}
|
|
|
|
llvm::Constant *
|
|
CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) {
|
|
// Member pointer constants always have a very particular form.
|
|
const MemberPointerType *type = cast<MemberPointerType>(uo->getType());
|
|
const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl();
|
|
|
|
// A member function pointer.
|
|
if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl))
|
|
return getCXXABI().EmitMemberFunctionPointer(method);
|
|
|
|
// Otherwise, a member data pointer.
|
|
uint64_t fieldOffset = getContext().getFieldOffset(decl);
|
|
CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset);
|
|
return getCXXABI().EmitMemberDataPointer(type, chars);
|
|
}
|
|
|
|
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
|
|
llvm::Type *baseType,
|
|
const CXXRecordDecl *base);
|
|
|
|
static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
|
|
const RecordDecl *record,
|
|
bool asCompleteObject) {
|
|
const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
|
|
llvm::StructType *structure =
|
|
(asCompleteObject ? layout.getLLVMType()
|
|
: layout.getBaseSubobjectLLVMType());
|
|
|
|
unsigned numElements = structure->getNumElements();
|
|
std::vector<llvm::Constant *> elements(numElements);
|
|
|
|
auto CXXR = dyn_cast<CXXRecordDecl>(record);
|
|
// Fill in all the bases.
|
|
if (CXXR) {
|
|
for (const auto &I : CXXR->bases()) {
|
|
if (I.isVirtual()) {
|
|
// Ignore virtual bases; if we're laying out for a complete
|
|
// object, we'll lay these out later.
|
|
continue;
|
|
}
|
|
|
|
const CXXRecordDecl *base =
|
|
cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
|
|
|
|
// Ignore empty bases.
|
|
if (base->isEmpty() ||
|
|
CGM.getContext().getASTRecordLayout(base).getNonVirtualSize()
|
|
.isZero())
|
|
continue;
|
|
|
|
unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
|
|
llvm::Type *baseType = structure->getElementType(fieldIndex);
|
|
elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
|
|
}
|
|
}
|
|
|
|
// Fill in all the fields.
|
|
for (const auto *Field : record->fields()) {
|
|
// Fill in non-bitfields. (Bitfields always use a zero pattern, which we
|
|
// will fill in later.)
|
|
if (!Field->isBitField() && !Field->isZeroSize(CGM.getContext())) {
|
|
unsigned fieldIndex = layout.getLLVMFieldNo(Field);
|
|
elements[fieldIndex] = CGM.EmitNullConstant(Field->getType());
|
|
}
|
|
|
|
// For unions, stop after the first named field.
|
|
if (record->isUnion()) {
|
|
if (Field->getIdentifier())
|
|
break;
|
|
if (const auto *FieldRD = Field->getType()->getAsRecordDecl())
|
|
if (FieldRD->findFirstNamedDataMember())
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Fill in the virtual bases, if we're working with the complete object.
|
|
if (CXXR && asCompleteObject) {
|
|
for (const auto &I : CXXR->vbases()) {
|
|
const CXXRecordDecl *base =
|
|
cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
|
|
|
|
// Ignore empty bases.
|
|
if (base->isEmpty())
|
|
continue;
|
|
|
|
unsigned fieldIndex = layout.getVirtualBaseIndex(base);
|
|
|
|
// We might have already laid this field out.
|
|
if (elements[fieldIndex]) continue;
|
|
|
|
llvm::Type *baseType = structure->getElementType(fieldIndex);
|
|
elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
|
|
}
|
|
}
|
|
|
|
// Now go through all other fields and zero them out.
|
|
for (unsigned i = 0; i != numElements; ++i) {
|
|
if (!elements[i])
|
|
elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
|
|
}
|
|
|
|
return llvm::ConstantStruct::get(structure, elements);
|
|
}
|
|
|
|
/// Emit the null constant for a base subobject.
|
|
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
|
|
llvm::Type *baseType,
|
|
const CXXRecordDecl *base) {
|
|
const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
|
|
|
|
// Just zero out bases that don't have any pointer to data members.
|
|
if (baseLayout.isZeroInitializableAsBase())
|
|
return llvm::Constant::getNullValue(baseType);
|
|
|
|
// Otherwise, we can just use its null constant.
|
|
return EmitNullConstant(CGM, base, /*asCompleteObject=*/false);
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM,
|
|
QualType T) {
|
|
return emitForMemory(CGM, CGM.EmitNullConstant(T), T);
|
|
}
|
|
|
|
llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
|
|
if (T->getAs<PointerType>())
|
|
return getNullPointer(
|
|
cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), T);
|
|
|
|
if (getTypes().isZeroInitializable(T))
|
|
return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
|
|
|
|
if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
|
|
llvm::ArrayType *ATy =
|
|
cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
|
|
|
|
QualType ElementTy = CAT->getElementType();
|
|
|
|
llvm::Constant *Element =
|
|
ConstantEmitter::emitNullForMemory(*this, ElementTy);
|
|
unsigned NumElements = CAT->getSize().getZExtValue();
|
|
SmallVector<llvm::Constant *, 8> Array(NumElements, Element);
|
|
return llvm::ConstantArray::get(ATy, Array);
|
|
}
|
|
|
|
if (const RecordType *RT = T->getAs<RecordType>())
|
|
return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true);
|
|
|
|
assert(T->isMemberDataPointerType() &&
|
|
"Should only see pointers to data members here!");
|
|
|
|
return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
|
|
}
|
|
|
|
llvm::Constant *
|
|
CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) {
|
|
return ::EmitNullConstant(*this, Record, false);
|
|
}
|