llvm-6502/lib/Target/X86/MCTargetDesc/X86WinCOFFObjectWriter.cpp
Nico Rieck 18d49acdab MC: Support COFF image-relative MCSymbolRefs
Add support for the COFF relocation types IMAGE_REL_I386_DIR32NB and
IMAGE_REL_AMD64_ADDR32NB for 32- and 64-bit respectively. These are
similar to normal 4-byte relocations except that they do not include
the base address of the image.

Image-relative relocations are used for debug information (32-bit) and
SEH unwind tables (64-bit).

A new MCSymbolRef variant called 'VK_COFF_IMGREL32' is introduced to
specify such relocations. For AT&T assembly, this variant can be accessed
using the symbol suffix '@imgrel'.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179240 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-10 23:28:17 +00:00

80 lines
2.7 KiB
C++

//===-- X86WinCOFFObjectWriter.cpp - X86 Win COFF Writer ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/X86FixupKinds.h"
#include "MCTargetDesc/X86MCTargetDesc.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/MCWinCOFFObjectWriter.h"
#include "llvm/Support/COFF.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
namespace llvm {
class MCObjectWriter;
}
namespace {
class X86WinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
const bool Is64Bit;
public:
X86WinCOFFObjectWriter(bool Is64Bit_);
~X86WinCOFFObjectWriter();
virtual unsigned getRelocType(const MCValue &Target,
const MCFixup &Fixup,
bool IsCrossSection) const LLVM_OVERRIDE;
};
}
X86WinCOFFObjectWriter::X86WinCOFFObjectWriter(bool Is64Bit_)
: MCWinCOFFObjectTargetWriter(Is64Bit_ ? COFF::IMAGE_FILE_MACHINE_AMD64 :
COFF::IMAGE_FILE_MACHINE_I386),
Is64Bit(Is64Bit_) {}
X86WinCOFFObjectWriter::~X86WinCOFFObjectWriter() {}
unsigned X86WinCOFFObjectWriter::getRelocType(const MCValue &Target,
const MCFixup &Fixup,
bool IsCrossSection) const {
unsigned FixupKind = IsCrossSection ? FK_PCRel_4 : Fixup.getKind();
MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
switch (FixupKind) {
case FK_PCRel_4:
case X86::reloc_riprel_4byte:
case X86::reloc_riprel_4byte_movq_load:
return Is64Bit ? COFF::IMAGE_REL_AMD64_REL32 : COFF::IMAGE_REL_I386_REL32;
case FK_Data_4:
case X86::reloc_signed_4byte:
if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
return Is64Bit ? COFF::IMAGE_REL_AMD64_ADDR32NB :
COFF::IMAGE_REL_I386_DIR32NB;
return Is64Bit ? COFF::IMAGE_REL_AMD64_ADDR32 : COFF::IMAGE_REL_I386_DIR32;
case FK_Data_8:
if (Is64Bit)
return COFF::IMAGE_REL_AMD64_ADDR64;
llvm_unreachable("unsupported relocation type");
case FK_SecRel_4:
return Is64Bit ? COFF::IMAGE_REL_AMD64_SECREL : COFF::IMAGE_REL_I386_SECREL;
default:
llvm_unreachable("unsupported relocation type");
}
}
MCObjectWriter *llvm::createX86WinCOFFObjectWriter(raw_ostream &OS,
bool Is64Bit) {
MCWinCOFFObjectTargetWriter *MOTW = new X86WinCOFFObjectWriter(Is64Bit);
return createWinCOFFObjectWriter(MOTW, OS);
}