llvm-6502/lib/Target/SystemZ/MCTargetDesc/SystemZMCObjectWriter.cpp
Rafael Espindola 930ca98433 Fix pr19645.
The fix itself is fairly simple: move getAccessVariant to MCValue so that we
replace the old weak expression evaluation with the far more general
EvaluateAsRelocatable.

This then requires that EvaluateAsRelocatable stop when it finds a non
trivial reference kind. And that in turn requires the ELF writer to look
harder for weak references.

Last but not least, this found a case where we were being bug by bug
compatible with gas and accepting an invalid input. I reported pr19647
to track it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207920 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-03 19:57:04 +00:00

116 lines
3.8 KiB
C++

//===-- SystemZMCObjectWriter.cpp - SystemZ ELF writer --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/SystemZMCTargetDesc.h"
#include "MCTargetDesc/SystemZMCFixups.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCValue.h"
using namespace llvm;
namespace {
class SystemZObjectWriter : public MCELFObjectTargetWriter {
public:
SystemZObjectWriter(uint8_t OSABI);
virtual ~SystemZObjectWriter();
protected:
// Override MCELFObjectTargetWriter.
unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
bool IsPCRel) const override;
};
} // end anonymous namespace
SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
: MCELFObjectTargetWriter(/*Is64Bit=*/true, OSABI, ELF::EM_S390,
/*HasRelocationAddend=*/ true) {}
SystemZObjectWriter::~SystemZObjectWriter() {
}
// Return the relocation type for an absolute value of MCFixupKind Kind.
static unsigned getAbsoluteReloc(unsigned Kind) {
switch (Kind) {
case FK_Data_1: return ELF::R_390_8;
case FK_Data_2: return ELF::R_390_16;
case FK_Data_4: return ELF::R_390_32;
case FK_Data_8: return ELF::R_390_64;
}
llvm_unreachable("Unsupported absolute address");
}
// Return the relocation type for a PC-relative value of MCFixupKind Kind.
static unsigned getPCRelReloc(unsigned Kind) {
switch (Kind) {
case FK_Data_2: return ELF::R_390_PC16;
case FK_Data_4: return ELF::R_390_PC32;
case FK_Data_8: return ELF::R_390_PC64;
case SystemZ::FK_390_PC16DBL: return ELF::R_390_PC16DBL;
case SystemZ::FK_390_PC32DBL: return ELF::R_390_PC32DBL;
case SystemZ::FK_390_PLT16DBL: return ELF::R_390_PLT16DBL;
case SystemZ::FK_390_PLT32DBL: return ELF::R_390_PLT32DBL;
}
llvm_unreachable("Unsupported PC-relative address");
}
// Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
static unsigned getTLSLEReloc(unsigned Kind) {
switch (Kind) {
case FK_Data_4: return ELF::R_390_TLS_LE32;
case FK_Data_8: return ELF::R_390_TLS_LE64;
}
llvm_unreachable("Unsupported absolute address");
}
// Return the PLT relocation counterpart of MCFixupKind Kind.
static unsigned getPLTReloc(unsigned Kind) {
switch (Kind) {
case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
}
llvm_unreachable("Unsupported absolute address");
}
unsigned SystemZObjectWriter::GetRelocType(const MCValue &Target,
const MCFixup &Fixup,
bool IsPCRel) const {
MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
unsigned Kind = Fixup.getKind();
switch (Modifier) {
case MCSymbolRefExpr::VK_None:
if (IsPCRel)
return getPCRelReloc(Kind);
return getAbsoluteReloc(Kind);
case MCSymbolRefExpr::VK_NTPOFF:
assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
return getTLSLEReloc(Kind);
case MCSymbolRefExpr::VK_GOT:
if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
return ELF::R_390_GOTENT;
llvm_unreachable("Only PC-relative GOT accesses are supported for now");
case MCSymbolRefExpr::VK_PLT:
assert(IsPCRel && "@PLT shouldt be PC-relative");
return getPLTReloc(Kind);
default:
llvm_unreachable("Modifier not supported");
}
}
MCObjectWriter *llvm::createSystemZObjectWriter(raw_ostream &OS,
uint8_t OSABI) {
MCELFObjectTargetWriter *MOTW = new SystemZObjectWriter(OSABI);
return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false);
}