llvm-project/llvm/lib/Target/ARM/ARMTargetObjectFile.cpp

96 lines
3.5 KiB
C++

//===-- llvm/Target/ARMTargetObjectFile.cpp - ARM Object Info Impl --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "ARMSubtarget.h"
#include "ARMTargetMachine.h"
#include "ARMTargetObjectFile.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ELF.h"
#include "llvm/Target/TargetMachine.h"
#include <cassert>
using namespace llvm;
using namespace dwarf;
//===----------------------------------------------------------------------===//
// ELF Target
//===----------------------------------------------------------------------===//
void ARMElfTargetObjectFile::Initialize(MCContext &Ctx,
const TargetMachine &TM) {
const ARMTargetMachine &ARM_TM = static_cast<const ARMTargetMachine &>(TM);
bool isAAPCS_ABI = ARM_TM.TargetABI == ARMTargetMachine::ARMABI::ARM_ABI_AAPCS;
genExecuteOnly = ARM_TM.getSubtargetImpl()->genExecuteOnly();
TargetLoweringObjectFileELF::Initialize(Ctx, TM);
InitializeELF(isAAPCS_ABI);
if (isAAPCS_ABI) {
LSDASection = nullptr;
}
AttributesSection =
getContext().getELFSection(".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
// Make code section unreadable when in execute-only mode
if (genExecuteOnly) {
unsigned Type = ELF::SHT_PROGBITS;
unsigned Flags = ELF::SHF_EXECINSTR | ELF::SHF_ALLOC | ELF::SHF_ARM_PURECODE;
// Since we cannot modify flags for an existing section, we create a new
// section with the right flags, and use 0 as the unique ID for
// execute-only text
TextSection = Ctx.getELFSection(".text", Type, Flags, 0, "", 0U);
}
}
const MCExpr *ARMElfTargetObjectFile::getTTypeGlobalReference(
const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM,
MachineModuleInfo *MMI, MCStreamer &Streamer) const {
if (TM.getMCAsmInfo()->getExceptionHandlingType() != ExceptionHandling::ARM)
return TargetLoweringObjectFileELF::getTTypeGlobalReference(
GV, Encoding, TM, MMI, Streamer);
assert(Encoding == DW_EH_PE_absptr && "Can handle absptr encoding only");
return MCSymbolRefExpr::create(TM.getSymbol(GV),
MCSymbolRefExpr::VK_ARM_TARGET2, getContext());
}
const MCExpr *ARMElfTargetObjectFile::
getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_ARM_TLSLDO,
getContext());
}
MCSection *
ARMElfTargetObjectFile::getExplicitSectionGlobal(const GlobalObject *GO,
SectionKind SK, const TargetMachine &TM) const {
// Set execute-only access for the explicit section
if (genExecuteOnly && SK.isText())
SK = SectionKind::getExecuteOnly();
return TargetLoweringObjectFileELF::getExplicitSectionGlobal(GO, SK, TM);
}
MCSection *
ARMElfTargetObjectFile::SelectSectionForGlobal(const GlobalObject *GO,
SectionKind SK, const TargetMachine &TM) const {
// Place the global in the execute-only text section
if (genExecuteOnly && SK.isText())
SK = SectionKind::getExecuteOnly();
return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, SK, TM);
}