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//===-- X86WinCOFFObjectWriter.cpp - X86 Win COFF Writer ------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/X86FixupKinds.h"
#include "MCTargetDesc/X86MCTargetDesc.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/MCWinCOFFObjectWriter.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
namespace {
class X86WinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
public:
X86WinCOFFObjectWriter(bool Is64Bit);
~X86WinCOFFObjectWriter() override = default;
unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
const MCFixup &Fixup, bool IsCrossSection,
const MCAsmBackend &MAB) const override;
};
} // end anonymous namespace
X86WinCOFFObjectWriter::X86WinCOFFObjectWriter(bool Is64Bit)
: MCWinCOFFObjectTargetWriter(Is64Bit ? COFF::IMAGE_FILE_MACHINE_AMD64
: COFF::IMAGE_FILE_MACHINE_I386) {}
unsigned X86WinCOFFObjectWriter::getRelocType(MCContext &Ctx,
const MCValue &Target,
const MCFixup &Fixup,
bool IsCrossSection,
const MCAsmBackend &MAB) const {
const bool Is64Bit = getMachine() == COFF::IMAGE_FILE_MACHINE_AMD64;
unsigned FixupKind = Fixup.getKind();
if (IsCrossSection) {
// IMAGE_REL_AMD64_REL64 does not exist. We treat FK_Data_8 as FK_PCRel_4 so
// that .quad a-b can lower to IMAGE_REL_AMD64_REL32. This allows generic
// instrumentation to not bother with the COFF limitation. A negative value
// needs attention.
if (FixupKind == FK_Data_4 || FixupKind == llvm::X86::reloc_signed_4byte ||
(FixupKind == FK_Data_8 && Is64Bit)) {
FixupKind = FK_PCRel_4;
} else {
Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
return COFF::IMAGE_REL_AMD64_ADDR32;
}
}
MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
if (Is64Bit) {
switch (FixupKind) {
case FK_PCRel_4:
case X86::reloc_riprel_4byte:
case X86::reloc_riprel_4byte_movq_load:
case X86::reloc_riprel_4byte_relax:
case X86::reloc_riprel_4byte_relax_rex:
case X86::reloc_branch_4byte_pcrel:
return COFF::IMAGE_REL_AMD64_REL32;
case FK_Data_4:
case X86::reloc_signed_4byte:
case X86::reloc_signed_4byte_relax:
if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
return COFF::IMAGE_REL_AMD64_ADDR32NB;
if (Modifier == MCSymbolRefExpr::VK_SECREL)
return COFF::IMAGE_REL_AMD64_SECREL;
return COFF::IMAGE_REL_AMD64_ADDR32;
case FK_Data_8:
return COFF::IMAGE_REL_AMD64_ADDR64;
case FK_SecRel_2:
return COFF::IMAGE_REL_AMD64_SECTION;
case FK_SecRel_4:
return COFF::IMAGE_REL_AMD64_SECREL;
default:
Ctx.reportError(Fixup.getLoc(), "unsupported relocation type");
return COFF::IMAGE_REL_AMD64_ADDR32;
}
} else if (getMachine() == COFF::IMAGE_FILE_MACHINE_I386) {
switch (FixupKind) {
case FK_PCRel_4:
case X86::reloc_riprel_4byte:
case X86::reloc_riprel_4byte_movq_load:
return COFF::IMAGE_REL_I386_REL32;
case FK_Data_4:
case X86::reloc_signed_4byte:
case X86::reloc_signed_4byte_relax:
if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
return COFF::IMAGE_REL_I386_DIR32NB;
if (Modifier == MCSymbolRefExpr::VK_SECREL)
return COFF::IMAGE_REL_I386_SECREL;
return COFF::IMAGE_REL_I386_DIR32;
case FK_SecRel_2:
return COFF::IMAGE_REL_I386_SECTION;
case FK_SecRel_4:
return COFF::IMAGE_REL_I386_SECREL;
default:
Ctx.reportError(Fixup.getLoc(), "unsupported relocation type");
return COFF::IMAGE_REL_I386_DIR32;
}
} else
llvm_unreachable("Unsupported COFF machine type.");
}
std::unique_ptr<MCObjectTargetWriter>
llvm::createX86WinCOFFObjectWriter(bool Is64Bit) {
return std::make_unique<X86WinCOFFObjectWriter>(Is64Bit);
}
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