forked from OSchip/llvm-project
2124 lines
75 KiB
C++
2124 lines
75 KiB
C++
//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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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 "CodeGenFunction.h"
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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 "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/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/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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// ConstStructBuilder
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//===----------------------------------------------------------------------===//
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namespace {
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class ConstExprEmitter;
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class ConstStructBuilder {
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CodeGenModule &CGM;
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ConstantEmitter &Emitter;
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bool Packed;
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CharUnits NextFieldOffsetInChars;
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CharUnits LLVMStructAlignment;
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SmallVector<llvm::Constant *, 32> Elements;
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public:
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static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
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ConstExprEmitter *ExprEmitter,
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llvm::ConstantStruct *Base,
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InitListExpr *Updater,
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QualType ValTy);
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static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
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InitListExpr *ILE, QualType StructTy);
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static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
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const APValue &Value, QualType ValTy);
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private:
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ConstStructBuilder(ConstantEmitter &emitter)
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: CGM(emitter.CGM), Emitter(emitter), Packed(false),
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NextFieldOffsetInChars(CharUnits::Zero()),
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LLVMStructAlignment(CharUnits::One()) { }
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void AppendField(const FieldDecl *Field, uint64_t FieldOffset,
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llvm::Constant *InitExpr);
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void AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst);
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void AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
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llvm::ConstantInt *InitExpr);
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void AppendPadding(CharUnits PadSize);
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void AppendTailPadding(CharUnits RecordSize);
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void ConvertStructToPacked();
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bool Build(InitListExpr *ILE);
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bool Build(ConstExprEmitter *Emitter, llvm::ConstantStruct *Base,
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InitListExpr *Updater);
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bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
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const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
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llvm::Constant *Finalize(QualType Ty);
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CharUnits getAlignment(const llvm::Constant *C) const {
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if (Packed) return CharUnits::One();
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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 getSizeInChars(const llvm::Constant *C) const {
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return CharUnits::fromQuantity(
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CGM.getDataLayout().getTypeAllocSize(C->getType()));
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}
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};
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void ConstStructBuilder::
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AppendField(const FieldDecl *Field, uint64_t FieldOffset,
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llvm::Constant *InitCst) {
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const ASTContext &Context = CGM.getContext();
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CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
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AppendBytes(FieldOffsetInChars, InitCst);
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}
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void ConstStructBuilder::
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AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst) {
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assert(NextFieldOffsetInChars <= FieldOffsetInChars
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&& "Field offset mismatch!");
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CharUnits FieldAlignment = getAlignment(InitCst);
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// Round up the field offset to the alignment of the field type.
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CharUnits AlignedNextFieldOffsetInChars =
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NextFieldOffsetInChars.alignTo(FieldAlignment);
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if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) {
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// We need to append padding.
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AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
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assert(NextFieldOffsetInChars == FieldOffsetInChars &&
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"Did not add enough padding!");
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AlignedNextFieldOffsetInChars =
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NextFieldOffsetInChars.alignTo(FieldAlignment);
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}
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if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) {
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assert(!Packed && "Alignment is wrong even with a packed struct!");
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// Convert the struct to a packed struct.
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ConvertStructToPacked();
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// After we pack the struct, we may need to insert padding.
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if (NextFieldOffsetInChars < FieldOffsetInChars) {
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// We need to append padding.
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AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
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assert(NextFieldOffsetInChars == FieldOffsetInChars &&
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"Did not add enough padding!");
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}
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AlignedNextFieldOffsetInChars = NextFieldOffsetInChars;
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}
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// Add the field.
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Elements.push_back(InitCst);
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NextFieldOffsetInChars = AlignedNextFieldOffsetInChars +
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getSizeInChars(InitCst);
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if (Packed)
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assert(LLVMStructAlignment == CharUnits::One() &&
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"Packed struct not byte-aligned!");
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else
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LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment);
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}
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void ConstStructBuilder::AppendBitField(const FieldDecl *Field,
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uint64_t FieldOffset,
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llvm::ConstantInt *CI) {
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const ASTContext &Context = CGM.getContext();
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const uint64_t CharWidth = Context.getCharWidth();
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uint64_t NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
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if (FieldOffset > NextFieldOffsetInBits) {
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// We need to add padding.
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CharUnits PadSize = Context.toCharUnitsFromBits(
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llvm::alignTo(FieldOffset - NextFieldOffsetInBits,
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Context.getTargetInfo().getCharAlign()));
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AppendPadding(PadSize);
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}
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uint64_t FieldSize = Field->getBitWidthValue(Context);
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llvm::APInt FieldValue = CI->getValue();
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// Promote the size of FieldValue if necessary
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// FIXME: This should never occur, but currently it can because initializer
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// constants are cast to bool, and because clang is not enforcing bitfield
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// width limits.
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if (FieldSize > FieldValue.getBitWidth())
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FieldValue = FieldValue.zext(FieldSize);
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// Truncate the size of FieldValue to the bit field size.
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if (FieldSize < FieldValue.getBitWidth())
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FieldValue = FieldValue.trunc(FieldSize);
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NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
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if (FieldOffset < NextFieldOffsetInBits) {
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// Either part of the field or the entire field can go into the previous
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// byte.
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assert(!Elements.empty() && "Elements can't be empty!");
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unsigned BitsInPreviousByte = NextFieldOffsetInBits - FieldOffset;
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bool FitsCompletelyInPreviousByte =
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BitsInPreviousByte >= FieldValue.getBitWidth();
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llvm::APInt Tmp = FieldValue;
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if (!FitsCompletelyInPreviousByte) {
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unsigned NewFieldWidth = FieldSize - BitsInPreviousByte;
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if (CGM.getDataLayout().isBigEndian()) {
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Tmp.lshrInPlace(NewFieldWidth);
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Tmp = Tmp.trunc(BitsInPreviousByte);
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// We want the remaining high bits.
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FieldValue = FieldValue.trunc(NewFieldWidth);
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} else {
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Tmp = Tmp.trunc(BitsInPreviousByte);
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// We want the remaining low bits.
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FieldValue.lshrInPlace(BitsInPreviousByte);
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FieldValue = FieldValue.trunc(NewFieldWidth);
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}
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}
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Tmp = Tmp.zext(CharWidth);
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if (CGM.getDataLayout().isBigEndian()) {
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if (FitsCompletelyInPreviousByte)
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Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth());
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} else {
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Tmp = Tmp.shl(CharWidth - BitsInPreviousByte);
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}
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// 'or' in the bits that go into the previous byte.
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llvm::Value *LastElt = Elements.back();
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if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(LastElt))
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Tmp |= Val->getValue();
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else {
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assert(isa<llvm::UndefValue>(LastElt));
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// If there is an undef field that we're adding to, it can either be a
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// scalar undef (in which case, we just replace it with our field) or it
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// is an array. If it is an array, we have to pull one byte off the
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// array so that the other undef bytes stay around.
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if (!isa<llvm::IntegerType>(LastElt->getType())) {
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// The undef padding will be a multibyte array, create a new smaller
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// padding and then an hole for our i8 to get plopped into.
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assert(isa<llvm::ArrayType>(LastElt->getType()) &&
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"Expected array padding of undefs");
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llvm::ArrayType *AT = cast<llvm::ArrayType>(LastElt->getType());
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assert(AT->getElementType()->isIntegerTy(CharWidth) &&
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AT->getNumElements() != 0 &&
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"Expected non-empty array padding of undefs");
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// Remove the padding array.
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NextFieldOffsetInChars -= CharUnits::fromQuantity(AT->getNumElements());
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Elements.pop_back();
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// Add the padding back in two chunks.
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AppendPadding(CharUnits::fromQuantity(AT->getNumElements()-1));
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AppendPadding(CharUnits::One());
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assert(isa<llvm::UndefValue>(Elements.back()) &&
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Elements.back()->getType()->isIntegerTy(CharWidth) &&
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"Padding addition didn't work right");
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}
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}
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Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp);
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if (FitsCompletelyInPreviousByte)
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return;
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}
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while (FieldValue.getBitWidth() > CharWidth) {
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llvm::APInt Tmp;
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if (CGM.getDataLayout().isBigEndian()) {
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// We want the high bits.
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Tmp =
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FieldValue.lshr(FieldValue.getBitWidth() - CharWidth).trunc(CharWidth);
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} else {
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// We want the low bits.
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Tmp = FieldValue.trunc(CharWidth);
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FieldValue.lshrInPlace(CharWidth);
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}
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Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp));
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++NextFieldOffsetInChars;
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FieldValue = FieldValue.trunc(FieldValue.getBitWidth() - CharWidth);
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}
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assert(FieldValue.getBitWidth() > 0 &&
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"Should have at least one bit left!");
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assert(FieldValue.getBitWidth() <= CharWidth &&
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"Should not have more than a byte left!");
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if (FieldValue.getBitWidth() < CharWidth) {
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if (CGM.getDataLayout().isBigEndian()) {
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unsigned BitWidth = FieldValue.getBitWidth();
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FieldValue = FieldValue.zext(CharWidth) << (CharWidth - BitWidth);
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} else
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FieldValue = FieldValue.zext(CharWidth);
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}
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// Append the last element.
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Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(),
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FieldValue));
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++NextFieldOffsetInChars;
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}
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void ConstStructBuilder::AppendPadding(CharUnits PadSize) {
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if (PadSize.isZero())
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return;
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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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llvm::Constant *C = llvm::UndefValue::get(Ty);
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Elements.push_back(C);
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assert(getAlignment(C) == CharUnits::One() &&
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"Padding must have 1 byte alignment!");
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NextFieldOffsetInChars += getSizeInChars(C);
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}
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void ConstStructBuilder::AppendTailPadding(CharUnits RecordSize) {
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assert(NextFieldOffsetInChars <= RecordSize &&
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"Size mismatch!");
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AppendPadding(RecordSize - NextFieldOffsetInChars);
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}
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void ConstStructBuilder::ConvertStructToPacked() {
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SmallVector<llvm::Constant *, 16> PackedElements;
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CharUnits ElementOffsetInChars = CharUnits::Zero();
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for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
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llvm::Constant *C = Elements[i];
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CharUnits ElementAlign = CharUnits::fromQuantity(
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CGM.getDataLayout().getABITypeAlignment(C->getType()));
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CharUnits AlignedElementOffsetInChars =
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ElementOffsetInChars.alignTo(ElementAlign);
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if (AlignedElementOffsetInChars > ElementOffsetInChars) {
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// We need some padding.
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CharUnits NumChars =
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AlignedElementOffsetInChars - ElementOffsetInChars;
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llvm::Type *Ty = CGM.Int8Ty;
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if (NumChars > CharUnits::One())
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Ty = llvm::ArrayType::get(Ty, NumChars.getQuantity());
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llvm::Constant *Padding = llvm::UndefValue::get(Ty);
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PackedElements.push_back(Padding);
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ElementOffsetInChars += getSizeInChars(Padding);
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}
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PackedElements.push_back(C);
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ElementOffsetInChars += getSizeInChars(C);
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}
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assert(ElementOffsetInChars == NextFieldOffsetInChars &&
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"Packing the struct changed its size!");
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Elements.swap(PackedElements);
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LLVMStructAlignment = CharUnits::One();
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Packed = true;
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}
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bool ConstStructBuilder::Build(InitListExpr *ILE) {
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RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
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const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
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unsigned FieldNo = 0;
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unsigned ElementNo = 0;
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// Bail out if we have base classes. We could support these, but they only
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// arise in C++1z where we will have already constant folded most interesting
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// cases. FIXME: There are still a few more cases we can handle this way.
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if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
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if (CXXRD->getNumBases())
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return false;
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for (RecordDecl::field_iterator Field = RD->field_begin(),
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FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
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// If this is a union, skip all the fields that aren't being initialized.
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if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field)
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continue;
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// Don't emit anonymous bitfields, they just affect layout.
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if (Field->isUnnamedBitfield())
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continue;
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// Get the initializer. A struct can include fields without initializers,
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// we just use explicit null values for them.
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llvm::Constant *EltInit;
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if (ElementNo < ILE->getNumInits())
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EltInit = Emitter.tryEmitPrivateForMemory(ILE->getInit(ElementNo++),
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Field->getType());
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else
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EltInit = Emitter.emitNullForMemory(Field->getType());
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if (!EltInit)
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return false;
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if (!Field->isBitField()) {
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// Handle non-bitfield members.
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AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit);
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} else {
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// Otherwise we have a bitfield.
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if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
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AppendBitField(*Field, Layout.getFieldOffset(FieldNo), CI);
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} else {
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// We are trying to initialize a bitfield with a non-trivial constant,
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// this must require run-time code.
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return false;
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}
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}
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}
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return true;
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}
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namespace {
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struct BaseInfo {
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BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index)
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: Decl(Decl), Offset(Offset), Index(Index) {
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}
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const CXXRecordDecl *Decl;
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CharUnits Offset;
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unsigned Index;
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bool operator<(const BaseInfo &O) const { return Offset < O.Offset; }
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};
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}
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bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
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bool IsPrimaryBase,
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const CXXRecordDecl *VTableClass,
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CharUnits Offset) {
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const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
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if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
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// Add a vtable pointer, if we need one and it hasn't already been added.
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if (CD->isDynamicClass() && !IsPrimaryBase) {
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llvm::Constant *VTableAddressPoint =
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CGM.getCXXABI().getVTableAddressPointForConstExpr(
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BaseSubobject(CD, Offset), VTableClass);
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AppendBytes(Offset, VTableAddressPoint);
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}
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// Accumulate and sort bases, in order to visit them in address order, which
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// may not be the same as declaration order.
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SmallVector<BaseInfo, 8> Bases;
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Bases.reserve(CD->getNumBases());
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unsigned BaseNo = 0;
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for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(),
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BaseEnd = CD->bases_end(); Base != BaseEnd; ++Base, ++BaseNo) {
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assert(!Base->isVirtual() && "should not have virtual bases here");
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const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl();
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CharUnits BaseOffset = Layout.getBaseClassOffset(BD);
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Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo));
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}
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std::stable_sort(Bases.begin(), Bases.end());
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for (unsigned I = 0, N = Bases.size(); I != N; ++I) {
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BaseInfo &Base = Bases[I];
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bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
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Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
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VTableClass, Offset + Base.Offset);
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}
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}
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unsigned FieldNo = 0;
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uint64_t OffsetBits = CGM.getContext().toBits(Offset);
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for (RecordDecl::field_iterator Field = RD->field_begin(),
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FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
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// If this is a union, skip all the fields that aren't being initialized.
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if (RD->isUnion() && Val.getUnionField() != *Field)
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continue;
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// Don't emit anonymous bitfields, they just affect layout.
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if (Field->isUnnamedBitfield())
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continue;
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// Emit the value of the initializer.
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const APValue &FieldValue =
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RD->isUnion() ? Val.getUnionValue() : Val.getStructField(FieldNo);
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llvm::Constant *EltInit =
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Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType());
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if (!EltInit)
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return false;
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if (!Field->isBitField()) {
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// Handle non-bitfield members.
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AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, EltInit);
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} else {
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// Otherwise we have a bitfield.
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AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
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cast<llvm::ConstantInt>(EltInit));
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}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
llvm::Constant *ConstStructBuilder::Finalize(QualType Ty) {
|
|
RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
|
|
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
|
|
|
|
CharUnits LayoutSizeInChars = Layout.getSize();
|
|
|
|
if (NextFieldOffsetInChars > LayoutSizeInChars) {
|
|
// If the struct is bigger than the size of the record type,
|
|
// we must have a flexible array member at the end.
|
|
assert(RD->hasFlexibleArrayMember() &&
|
|
"Must have flexible array member if struct is bigger than type!");
|
|
|
|
// No tail padding is necessary.
|
|
} else {
|
|
// Append tail padding if necessary.
|
|
CharUnits LLVMSizeInChars =
|
|
NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
|
|
|
|
if (LLVMSizeInChars != LayoutSizeInChars)
|
|
AppendTailPadding(LayoutSizeInChars);
|
|
|
|
LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
|
|
|
|
// Check if we need to convert the struct to a packed struct.
|
|
if (NextFieldOffsetInChars <= LayoutSizeInChars &&
|
|
LLVMSizeInChars > LayoutSizeInChars) {
|
|
assert(!Packed && "Size mismatch!");
|
|
|
|
ConvertStructToPacked();
|
|
assert(NextFieldOffsetInChars <= LayoutSizeInChars &&
|
|
"Converting to packed did not help!");
|
|
}
|
|
|
|
LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
|
|
|
|
assert(LayoutSizeInChars == LLVMSizeInChars &&
|
|
"Tail padding mismatch!");
|
|
}
|
|
|
|
// Pick the type to use. If the type is layout identical to the ConvertType
|
|
// type then use it, otherwise use whatever the builder produced for us.
|
|
llvm::StructType *STy =
|
|
llvm::ConstantStruct::getTypeForElements(CGM.getLLVMContext(),
|
|
Elements, Packed);
|
|
llvm::Type *ValTy = CGM.getTypes().ConvertType(Ty);
|
|
if (llvm::StructType *ValSTy = dyn_cast<llvm::StructType>(ValTy)) {
|
|
if (ValSTy->isLayoutIdentical(STy))
|
|
STy = ValSTy;
|
|
}
|
|
|
|
llvm::Constant *Result = llvm::ConstantStruct::get(STy, Elements);
|
|
|
|
assert(NextFieldOffsetInChars.alignTo(getAlignment(Result)) ==
|
|
getSizeInChars(Result) &&
|
|
"Size mismatch!");
|
|
|
|
return Result;
|
|
}
|
|
|
|
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
|
|
ConstExprEmitter *ExprEmitter,
|
|
llvm::ConstantStruct *Base,
|
|
InitListExpr *Updater,
|
|
QualType ValTy) {
|
|
ConstStructBuilder Builder(Emitter);
|
|
if (!Builder.Build(ExprEmitter, Base, Updater))
|
|
return nullptr;
|
|
return Builder.Finalize(ValTy);
|
|
}
|
|
|
|
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
|
|
InitListExpr *ILE,
|
|
QualType ValTy) {
|
|
ConstStructBuilder Builder(Emitter);
|
|
|
|
if (!Builder.Build(ILE))
|
|
return nullptr;
|
|
|
|
return Builder.Finalize(ValTy);
|
|
}
|
|
|
|
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
|
|
const APValue &Val,
|
|
QualType ValTy) {
|
|
ConstStructBuilder Builder(Emitter);
|
|
|
|
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);
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// 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.getQuantity());
|
|
CGM.setAddrOfConstantCompoundLiteral(E, GV);
|
|
return ConstantAddress(GV, Align);
|
|
}
|
|
|
|
/// This class only needs to handle two cases:
|
|
/// 1) Literals (this is used by APValue emission to emit literals).
|
|
/// 2) Arrays, structs and unions (outside C++11 mode, we don't currently
|
|
/// constant fold these types).
|
|
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 *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_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_ZeroToOCLEvent:
|
|
case CK_ZeroToOCLQueue:
|
|
return nullptr;
|
|
}
|
|
llvm_unreachable("Invalid CastKind");
|
|
}
|
|
|
|
llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE, QualType T) {
|
|
return Visit(DAE->getExpr(), T);
|
|
}
|
|
|
|
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) {
|
|
if (!E->cleanupsHaveSideEffects())
|
|
return Visit(E->getSubExpr(), T);
|
|
return nullptr;
|
|
}
|
|
|
|
llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
|
|
QualType T) {
|
|
return Visit(E->GetTemporaryExpr(), T);
|
|
}
|
|
|
|
llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
|
|
llvm::ArrayType *AType =
|
|
cast<llvm::ArrayType>(ConvertType(ILE->getType()));
|
|
llvm::Type *ElemTy = AType->getElementType();
|
|
unsigned NumInitElements = ILE->getNumInits();
|
|
unsigned NumElements = AType->getNumElements();
|
|
|
|
// Initialising an array requires us to automatically
|
|
// initialise any elements that have not been initialised explicitly
|
|
unsigned NumInitableElts = std::min(NumInitElements, NumElements);
|
|
|
|
QualType EltType = CGM.getContext().getAsArrayType(T)->getElementType();
|
|
|
|
// Initialize remaining array elements.
|
|
llvm::Constant *fillC;
|
|
if (Expr *filler = ILE->getArrayFiller())
|
|
fillC = Emitter.tryEmitAbstractForMemory(filler, EltType);
|
|
else
|
|
fillC = Emitter.emitNullForMemory(EltType);
|
|
if (!fillC)
|
|
return nullptr;
|
|
|
|
// Try to use a ConstantAggregateZero if we can.
|
|
if (fillC->isNullValue() && !NumInitableElts)
|
|
return llvm::ConstantAggregateZero::get(AType);
|
|
|
|
// Copy initializer elements.
|
|
SmallVector<llvm::Constant*, 16> Elts;
|
|
Elts.reserve(NumInitableElts + NumElements);
|
|
|
|
bool RewriteType = false;
|
|
for (unsigned i = 0; i < NumInitableElts; ++i) {
|
|
Expr *Init = ILE->getInit(i);
|
|
llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType);
|
|
if (!C)
|
|
return nullptr;
|
|
RewriteType |= (C->getType() != ElemTy);
|
|
Elts.push_back(C);
|
|
}
|
|
|
|
RewriteType |= (fillC->getType() != ElemTy);
|
|
Elts.resize(NumElements, fillC);
|
|
|
|
if (RewriteType) {
|
|
// FIXME: Try to avoid packing the array
|
|
std::vector<llvm::Type*> Types;
|
|
Types.reserve(NumInitableElts + NumElements);
|
|
for (unsigned i = 0, e = Elts.size(); i < e; ++i)
|
|
Types.push_back(Elts[i]->getType());
|
|
llvm::StructType *SType = llvm::StructType::get(AType->getContext(),
|
|
Types, true);
|
|
return llvm::ConstantStruct::get(SType, Elts);
|
|
}
|
|
|
|
return llvm::ConstantArray::get(AType, Elts);
|
|
}
|
|
|
|
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 *EmitDesignatedInitUpdater(llvm::Constant *Base,
|
|
InitListExpr *Updater,
|
|
QualType destType) {
|
|
if (auto destAT = CGM.getContext().getAsArrayType(destType)) {
|
|
llvm::ArrayType *AType = cast<llvm::ArrayType>(ConvertType(destType));
|
|
llvm::Type *ElemType = AType->getElementType();
|
|
|
|
unsigned NumInitElements = Updater->getNumInits();
|
|
unsigned NumElements = AType->getNumElements();
|
|
|
|
std::vector<llvm::Constant *> Elts;
|
|
Elts.reserve(NumElements);
|
|
|
|
QualType destElemType = destAT->getElementType();
|
|
|
|
if (auto DataArray = dyn_cast<llvm::ConstantDataArray>(Base))
|
|
for (unsigned i = 0; i != NumElements; ++i)
|
|
Elts.push_back(DataArray->getElementAsConstant(i));
|
|
else if (auto Array = dyn_cast<llvm::ConstantArray>(Base))
|
|
for (unsigned i = 0; i != NumElements; ++i)
|
|
Elts.push_back(Array->getOperand(i));
|
|
else
|
|
return nullptr; // FIXME: other array types not implemented
|
|
|
|
llvm::Constant *fillC = nullptr;
|
|
if (Expr *filler = Updater->getArrayFiller())
|
|
if (!isa<NoInitExpr>(filler))
|
|
fillC = Emitter.tryEmitAbstractForMemory(filler, destElemType);
|
|
bool RewriteType = (fillC && fillC->getType() != ElemType);
|
|
|
|
for (unsigned i = 0; i != NumElements; ++i) {
|
|
Expr *Init = nullptr;
|
|
if (i < NumInitElements)
|
|
Init = Updater->getInit(i);
|
|
|
|
if (!Init && fillC)
|
|
Elts[i] = fillC;
|
|
else if (!Init || isa<NoInitExpr>(Init))
|
|
; // Do nothing.
|
|
else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
|
|
Elts[i] = EmitDesignatedInitUpdater(Elts[i], ChildILE, destElemType);
|
|
else
|
|
Elts[i] = Emitter.tryEmitPrivateForMemory(Init, destElemType);
|
|
|
|
if (!Elts[i])
|
|
return nullptr;
|
|
RewriteType |= (Elts[i]->getType() != ElemType);
|
|
}
|
|
|
|
if (RewriteType) {
|
|
std::vector<llvm::Type *> Types;
|
|
Types.reserve(NumElements);
|
|
for (unsigned i = 0; i != NumElements; ++i)
|
|
Types.push_back(Elts[i]->getType());
|
|
llvm::StructType *SType = llvm::StructType::get(AType->getContext(),
|
|
Types, true);
|
|
return llvm::ConstantStruct::get(SType, Elts);
|
|
}
|
|
|
|
return llvm::ConstantArray::get(AType, Elts);
|
|
}
|
|
|
|
if (destType->isRecordType())
|
|
return ConstStructBuilder::BuildStruct(Emitter, this,
|
|
dyn_cast<llvm::ConstantStruct>(Base), Updater, destType);
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
|
|
QualType destType) {
|
|
auto C = Visit(E->getBase(), destType);
|
|
if (!C) return nullptr;
|
|
return EmitDesignatedInitUpdater(C, E->getUpdater(), destType);
|
|
}
|
|
|
|
llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
|
|
if (!E->getConstructor()->isTrivial())
|
|
return nullptr;
|
|
|
|
// FIXME: We should not have to call getBaseElementType here.
|
|
const RecordType *RT =
|
|
CGM.getContext().getBaseElementType(Ty)->getAs<RecordType>();
|
|
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
|
|
|
|
// If the class doesn't have a trivial destructor, we can't emit it as a
|
|
// constant expr.
|
|
if (!RD->hasTrivialDestructor())
|
|
return nullptr;
|
|
|
|
// Only copy and default 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) {
|
|
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.
|
|
|
|
bool ConstStructBuilder::Build(ConstExprEmitter *ExprEmitter,
|
|
llvm::ConstantStruct *Base,
|
|
InitListExpr *Updater) {
|
|
assert(Base && "base expression should not be empty");
|
|
|
|
QualType ExprType = Updater->getType();
|
|
RecordDecl *RD = ExprType->getAs<RecordType>()->getDecl();
|
|
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
|
|
const llvm::StructLayout *BaseLayout = CGM.getDataLayout().getStructLayout(
|
|
Base->getType());
|
|
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 (RD->isUnion() && Updater->getInitializedFieldInUnion() != Field)
|
|
continue;
|
|
|
|
// Skip anonymous bitfields.
|
|
if (Field->isUnnamedBitfield())
|
|
continue;
|
|
|
|
llvm::Constant *EltInit = Base->getOperand(ElementNo);
|
|
|
|
// Bail out if the type of the ConstantStruct does not have the same layout
|
|
// as the type of the InitListExpr.
|
|
if (CGM.getTypes().ConvertType(Field->getType()) != EltInit->getType() ||
|
|
Layout.getFieldOffset(ElementNo) !=
|
|
BaseLayout->getElementOffsetInBits(ElementNo))
|
|
return false;
|
|
|
|
// Get the initializer. If we encounter an empty field or a NoInitExpr,
|
|
// we use values from the base expression.
|
|
Expr *Init = nullptr;
|
|
if (ElementNo < Updater->getNumInits())
|
|
Init = Updater->getInit(ElementNo);
|
|
|
|
if (!Init || isa<NoInitExpr>(Init))
|
|
; // Do nothing.
|
|
else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
|
|
EltInit = ExprEmitter->EmitDesignatedInitUpdater(EltInit, ChildILE,
|
|
Field->getType());
|
|
else
|
|
EltInit = Emitter.tryEmitPrivateForMemory(Init, Field->getType());
|
|
|
|
++ElementNo;
|
|
|
|
if (!EltInit)
|
|
return false;
|
|
|
|
if (!Field->isBitField())
|
|
AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit);
|
|
else if (llvm::ConstantInt *CI = dyn_cast<llvm::ConstantInt>(EltInit))
|
|
AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI);
|
|
else
|
|
// Initializing a bitfield with a non-trivial constant?
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
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::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());
|
|
}
|
|
}
|
|
|
|
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());
|
|
|
|
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(false) {}
|
|
|
|
/*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 VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
|
|
ConstantLValue VisitStringLiteral(const StringLiteral *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 VisitCXXUuidofExpr(const CXXUuidofExpr *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();
|
|
|
|
// Certain special array initializers are represented in APValue
|
|
// as l-values referring to the base expression which generates the
|
|
// array. This happens with e.g. string literals. These should
|
|
// probably just get their own representation kind in APValue.
|
|
if (DestType->isArrayType()) {
|
|
assert(!hasNonZeroOffset() && "offset on array initializer");
|
|
auto expr = const_cast<Expr*>(base.get<const Expr*>());
|
|
return ConstExprEmitter(Emitter).Visit(expr, DestType);
|
|
}
|
|
|
|
// Otherwise, 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) {
|
|
auto offset = getOffset();
|
|
|
|
// If we're producing a pointer, this is easy.
|
|
if (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 = offset;
|
|
C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy,
|
|
/*isSigned*/ false);
|
|
C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy);
|
|
return C;
|
|
}
|
|
|
|
// Otherwise, we're basically returning an integer constant.
|
|
|
|
// FIXME: this does the wrong thing with ptrtoint of a null pointer,
|
|
// but since we don't know the original pointer type, there's not much
|
|
// we can do about it.
|
|
|
|
auto C = getOffset();
|
|
C = llvm::ConstantExpr::getIntegerCast(C, destTy, /*isSigned*/ false);
|
|
return C;
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
|
|
// Handle values.
|
|
if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
|
|
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));
|
|
}
|
|
}
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
// Otherwise, it must be an expression.
|
|
return Visit(base.get<const Expr*>());
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
|
|
auto C = CGM.getObjCRuntime().GenerateConstantString(E->getString());
|
|
return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(E->getType()));
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
|
|
if (auto CGF = Emitter.CGF) {
|
|
LValue Res = CGF->EmitPredefinedLValue(E);
|
|
return cast<ConstantAddress>(Res.getAddress());
|
|
}
|
|
|
|
auto kind = E->getIdentType();
|
|
if (kind == PredefinedExpr::PrettyFunction) {
|
|
return CGM.GetAddrOfConstantCString("top level", ".tmp");
|
|
}
|
|
|
|
return CGM.GetAddrOfConstantCString("", ".tmp");
|
|
}
|
|
|
|
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::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
|
|
return CGM.GetAddrOfUuidDescriptor(E);
|
|
}
|
|
|
|
ConstantLValue
|
|
ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
|
|
const MaterializeTemporaryExpr *E) {
|
|
assert(E->getStorageDuration() == SD_Static);
|
|
SmallVector<const Expr *, 2> CommaLHSs;
|
|
SmallVector<SubobjectAdjustment, 2> Adjustments;
|
|
const Expr *Inner = E->GetTemporaryExpr()
|
|
->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
|
|
return CGM.GetAddrOfGlobalTemporary(E, Inner);
|
|
}
|
|
|
|
llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
|
|
QualType DestType) {
|
|
switch (Value.getKind()) {
|
|
case APValue::Uninitialized:
|
|
llvm_unreachable("Constant expressions should be initialized.");
|
|
case APValue::LValue:
|
|
return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
|
|
case APValue::Int:
|
|
return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
|
|
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 *CAT = 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(),
|
|
CAT->getElementType());
|
|
|
|
// Emit initializer elements.
|
|
llvm::Type *CommonElementType =
|
|
CGM.getTypes().ConvertType(CAT->getElementType());
|
|
|
|
// Try to use a ConstantAggregateZero if we can.
|
|
if (Filler && Filler->isNullValue() && !NumInitElts) {
|
|
llvm::ArrayType *AType =
|
|
llvm::ArrayType::get(CommonElementType, NumElements);
|
|
return llvm::ConstantAggregateZero::get(AType);
|
|
}
|
|
|
|
SmallVector<llvm::Constant*, 16> Elts;
|
|
Elts.reserve(NumElements);
|
|
for (unsigned I = 0; I < NumElements; ++I) {
|
|
llvm::Constant *C = Filler;
|
|
if (I < NumInitElts) {
|
|
C = tryEmitPrivateForMemory(Value.getArrayInitializedElt(I),
|
|
CAT->getElementType());
|
|
} else if (!Filler) {
|
|
assert(Value.hasArrayFiller() &&
|
|
"Missing filler for implicit elements of initializer");
|
|
C = tryEmitPrivateForMemory(Value.getArrayFiller(),
|
|
CAT->getElementType());
|
|
}
|
|
if (!C) return nullptr;
|
|
|
|
if (I == 0)
|
|
CommonElementType = C->getType();
|
|
else if (C->getType() != CommonElementType)
|
|
CommonElementType = nullptr;
|
|
Elts.push_back(C);
|
|
}
|
|
|
|
if (!CommonElementType) {
|
|
// FIXME: Try to avoid packing the array
|
|
std::vector<llvm::Type*> Types;
|
|
Types.reserve(NumElements);
|
|
for (unsigned i = 0, e = Elts.size(); i < e; ++i)
|
|
Types.push_back(Elts[i]->getType());
|
|
llvm::StructType *SType =
|
|
llvm::StructType::get(CGM.getLLVMContext(), Types, true);
|
|
return llvm::ConstantStruct::get(SType, Elts);
|
|
}
|
|
|
|
llvm::ArrayType *AType =
|
|
llvm::ArrayType::get(CommonElementType, NumElements);
|
|
return llvm::ConstantArray::get(AType, Elts);
|
|
}
|
|
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()) {
|
|
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 =
|
|
dyn_cast_or_null<RecordDecl>(Field->getType()->getAsTagDecl()))
|
|
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);
|
|
}
|