2946cd7010
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
260 lines
8.6 KiB
C++
260 lines
8.6 KiB
C++
//===-- ARMELFObjectWriter.cpp - ARM ELF 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/ARMFixupKinds.h"
|
|
#include "MCTargetDesc/ARMMCTargetDesc.h"
|
|
#include "llvm/BinaryFormat/ELF.h"
|
|
#include "llvm/MC/MCContext.h"
|
|
#include "llvm/MC/MCELFObjectWriter.h"
|
|
#include "llvm/MC/MCExpr.h"
|
|
#include "llvm/MC/MCFixup.h"
|
|
#include "llvm/MC/MCObjectFileInfo.h"
|
|
#include "llvm/MC/MCObjectWriter.h"
|
|
#include "llvm/MC/MCValue.h"
|
|
#include "llvm/Support/ErrorHandling.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include <cstdint>
|
|
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
|
|
class ARMELFObjectWriter : public MCELFObjectTargetWriter {
|
|
enum { DefaultEABIVersion = 0x05000000U };
|
|
|
|
unsigned GetRelocTypeInner(const MCValue &Target, const MCFixup &Fixup,
|
|
bool IsPCRel, MCContext &Ctx) const;
|
|
|
|
public:
|
|
ARMELFObjectWriter(uint8_t OSABI);
|
|
|
|
~ARMELFObjectWriter() override = default;
|
|
|
|
unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
|
|
const MCFixup &Fixup, bool IsPCRel) const override;
|
|
|
|
bool needsRelocateWithSymbol(const MCSymbol &Sym,
|
|
unsigned Type) const override;
|
|
|
|
void addTargetSectionFlags(MCContext &Ctx, MCSectionELF &Sec) override;
|
|
};
|
|
|
|
} // end anonymous namespace
|
|
|
|
ARMELFObjectWriter::ARMELFObjectWriter(uint8_t OSABI)
|
|
: MCELFObjectTargetWriter(/*Is64Bit*/ false, OSABI,
|
|
ELF::EM_ARM,
|
|
/*HasRelocationAddend*/ false) {}
|
|
|
|
bool ARMELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym,
|
|
unsigned Type) const {
|
|
// FIXME: This is extremely conservative. This really needs to use a
|
|
// whitelist with a clear explanation for why each realocation needs to
|
|
// point to the symbol, not to the section.
|
|
switch (Type) {
|
|
default:
|
|
return true;
|
|
|
|
case ELF::R_ARM_PREL31:
|
|
case ELF::R_ARM_ABS32:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Need to examine the Fixup when determining whether to
|
|
// emit the relocation as an explicit symbol or as a section relative
|
|
// offset
|
|
unsigned ARMELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
|
|
const MCFixup &Fixup,
|
|
bool IsPCRel) const {
|
|
return GetRelocTypeInner(Target, Fixup, IsPCRel, Ctx);
|
|
}
|
|
|
|
unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
|
|
const MCFixup &Fixup,
|
|
bool IsPCRel,
|
|
MCContext &Ctx) const {
|
|
MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
|
|
|
|
if (IsPCRel) {
|
|
switch ((unsigned)Fixup.getKind()) {
|
|
default:
|
|
Ctx.reportFatalError(Fixup.getLoc(), "unsupported relocation on symbol");
|
|
return ELF::R_ARM_NONE;
|
|
case FK_Data_4:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("Unsupported Modifier");
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_REL32;
|
|
case MCSymbolRefExpr::VK_GOTTPOFF:
|
|
return ELF::R_ARM_TLS_IE32;
|
|
case MCSymbolRefExpr::VK_ARM_GOT_PREL:
|
|
return ELF::R_ARM_GOT_PREL;
|
|
case MCSymbolRefExpr::VK_ARM_PREL31:
|
|
return ELF::R_ARM_PREL31;
|
|
}
|
|
case ARM::fixup_arm_blx:
|
|
case ARM::fixup_arm_uncondbl:
|
|
switch (Modifier) {
|
|
case MCSymbolRefExpr::VK_PLT:
|
|
return ELF::R_ARM_CALL;
|
|
case MCSymbolRefExpr::VK_TLSCALL:
|
|
return ELF::R_ARM_TLS_CALL;
|
|
default:
|
|
return ELF::R_ARM_CALL;
|
|
}
|
|
case ARM::fixup_arm_condbl:
|
|
case ARM::fixup_arm_condbranch:
|
|
case ARM::fixup_arm_uncondbranch:
|
|
return ELF::R_ARM_JUMP24;
|
|
case ARM::fixup_t2_condbranch:
|
|
return ELF::R_ARM_THM_JUMP19;
|
|
case ARM::fixup_t2_uncondbranch:
|
|
return ELF::R_ARM_THM_JUMP24;
|
|
case ARM::fixup_arm_movt_hi16:
|
|
return ELF::R_ARM_MOVT_PREL;
|
|
case ARM::fixup_arm_movw_lo16:
|
|
return ELF::R_ARM_MOVW_PREL_NC;
|
|
case ARM::fixup_t2_movt_hi16:
|
|
return ELF::R_ARM_THM_MOVT_PREL;
|
|
case ARM::fixup_t2_movw_lo16:
|
|
return ELF::R_ARM_THM_MOVW_PREL_NC;
|
|
case ARM::fixup_arm_thumb_br:
|
|
return ELF::R_ARM_THM_JUMP11;
|
|
case ARM::fixup_arm_thumb_bcc:
|
|
return ELF::R_ARM_THM_JUMP8;
|
|
case ARM::fixup_arm_thumb_bl:
|
|
case ARM::fixup_arm_thumb_blx:
|
|
switch (Modifier) {
|
|
case MCSymbolRefExpr::VK_TLSCALL:
|
|
return ELF::R_ARM_THM_TLS_CALL;
|
|
default:
|
|
return ELF::R_ARM_THM_CALL;
|
|
}
|
|
}
|
|
}
|
|
switch ((unsigned)Fixup.getKind()) {
|
|
default:
|
|
Ctx.reportFatalError(Fixup.getLoc(), "unsupported relocation on symbol");
|
|
return ELF::R_ARM_NONE;
|
|
case FK_Data_1:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("unsupported Modifier");
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_ABS8;
|
|
}
|
|
case FK_Data_2:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("unsupported modifier");
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_ABS16;
|
|
}
|
|
case FK_Data_4:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("Unsupported Modifier");
|
|
case MCSymbolRefExpr::VK_ARM_NONE:
|
|
return ELF::R_ARM_NONE;
|
|
case MCSymbolRefExpr::VK_GOT:
|
|
return ELF::R_ARM_GOT_BREL;
|
|
case MCSymbolRefExpr::VK_TLSGD:
|
|
return ELF::R_ARM_TLS_GD32;
|
|
case MCSymbolRefExpr::VK_TPOFF:
|
|
return ELF::R_ARM_TLS_LE32;
|
|
case MCSymbolRefExpr::VK_GOTTPOFF:
|
|
return ELF::R_ARM_TLS_IE32;
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_ABS32;
|
|
case MCSymbolRefExpr::VK_GOTOFF:
|
|
return ELF::R_ARM_GOTOFF32;
|
|
case MCSymbolRefExpr::VK_ARM_GOT_PREL:
|
|
return ELF::R_ARM_GOT_PREL;
|
|
case MCSymbolRefExpr::VK_ARM_TARGET1:
|
|
return ELF::R_ARM_TARGET1;
|
|
case MCSymbolRefExpr::VK_ARM_TARGET2:
|
|
return ELF::R_ARM_TARGET2;
|
|
case MCSymbolRefExpr::VK_ARM_PREL31:
|
|
return ELF::R_ARM_PREL31;
|
|
case MCSymbolRefExpr::VK_ARM_SBREL:
|
|
return ELF::R_ARM_SBREL32;
|
|
case MCSymbolRefExpr::VK_ARM_TLSLDO:
|
|
return ELF::R_ARM_TLS_LDO32;
|
|
case MCSymbolRefExpr::VK_TLSCALL:
|
|
return ELF::R_ARM_TLS_CALL;
|
|
case MCSymbolRefExpr::VK_TLSDESC:
|
|
return ELF::R_ARM_TLS_GOTDESC;
|
|
case MCSymbolRefExpr::VK_TLSLDM:
|
|
return ELF::R_ARM_TLS_LDM32;
|
|
case MCSymbolRefExpr::VK_ARM_TLSDESCSEQ:
|
|
return ELF::R_ARM_TLS_DESCSEQ;
|
|
}
|
|
case ARM::fixup_arm_condbranch:
|
|
case ARM::fixup_arm_uncondbranch:
|
|
return ELF::R_ARM_JUMP24;
|
|
case ARM::fixup_arm_movt_hi16:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("Unsupported Modifier");
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_MOVT_ABS;
|
|
case MCSymbolRefExpr::VK_ARM_SBREL:
|
|
return ELF::R_ARM_MOVT_BREL;
|
|
}
|
|
case ARM::fixup_arm_movw_lo16:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("Unsupported Modifier");
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_MOVW_ABS_NC;
|
|
case MCSymbolRefExpr::VK_ARM_SBREL:
|
|
return ELF::R_ARM_MOVW_BREL_NC;
|
|
}
|
|
case ARM::fixup_t2_movt_hi16:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("Unsupported Modifier");
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_THM_MOVT_ABS;
|
|
case MCSymbolRefExpr::VK_ARM_SBREL:
|
|
return ELF::R_ARM_THM_MOVT_BREL;
|
|
}
|
|
case ARM::fixup_t2_movw_lo16:
|
|
switch (Modifier) {
|
|
default:
|
|
llvm_unreachable("Unsupported Modifier");
|
|
case MCSymbolRefExpr::VK_None:
|
|
return ELF::R_ARM_THM_MOVW_ABS_NC;
|
|
case MCSymbolRefExpr::VK_ARM_SBREL:
|
|
return ELF::R_ARM_THM_MOVW_BREL_NC;
|
|
}
|
|
}
|
|
}
|
|
|
|
void ARMELFObjectWriter::addTargetSectionFlags(MCContext &Ctx,
|
|
MCSectionELF &Sec) {
|
|
// The mix of execute-only and non-execute-only at link time is
|
|
// non-execute-only. To avoid the empty implicitly created .text
|
|
// section from making the whole .text section non-execute-only, we
|
|
// mark it execute-only if it is empty and there is at least one
|
|
// execute-only section in the object.
|
|
MCSectionELF *TextSection =
|
|
static_cast<MCSectionELF *>(Ctx.getObjectFileInfo()->getTextSection());
|
|
if (Sec.getKind().isExecuteOnly() && !TextSection->hasInstructions() &&
|
|
!TextSection->hasData()) {
|
|
TextSection->setFlags(TextSection->getFlags() | ELF::SHF_ARM_PURECODE);
|
|
}
|
|
}
|
|
|
|
std::unique_ptr<MCObjectTargetWriter>
|
|
llvm::createARMELFObjectWriter(uint8_t OSABI) {
|
|
return llvm::make_unique<ARMELFObjectWriter>(OSABI);
|
|
}
|