109 lines
4.0 KiB
C++
109 lines
4.0 KiB
C++
//===-- llvm/Target/ARMTargetObjectFile.cpp - ARM Object Info Impl --------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "ARMTargetObjectFile.h"
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#include "ARMSubtarget.h"
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#include "ARMTargetMachine.h"
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#include "llvm/BinaryFormat/Dwarf.h"
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#include "llvm/BinaryFormat/ELF.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCSectionELF.h"
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#include "llvm/MC/MCTargetOptions.h"
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#include "llvm/MC/SectionKind.h"
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#include "llvm/Target/TargetMachine.h"
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#include <cassert>
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using namespace llvm;
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using namespace dwarf;
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//===----------------------------------------------------------------------===//
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// ELF Target
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//===----------------------------------------------------------------------===//
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void ARMElfTargetObjectFile::Initialize(MCContext &Ctx,
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const TargetMachine &TM) {
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const ARMBaseTargetMachine &ARM_TM = static_cast<const ARMBaseTargetMachine &>(TM);
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bool isAAPCS_ABI = ARM_TM.TargetABI == ARMBaseTargetMachine::ARMABI::ARM_ABI_AAPCS;
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bool genExecuteOnly =
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ARM_TM.getMCSubtargetInfo()->hasFeature(ARM::FeatureExecuteOnly);
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TargetLoweringObjectFileELF::Initialize(Ctx, TM);
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InitializeELF(isAAPCS_ABI);
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if (isAAPCS_ABI) {
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LSDASection = nullptr;
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}
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// Make code section unreadable when in execute-only mode
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if (genExecuteOnly) {
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unsigned Type = ELF::SHT_PROGBITS;
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unsigned Flags =
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ELF::SHF_EXECINSTR | ELF::SHF_ALLOC | ELF::SHF_ARM_PURECODE;
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// Since we cannot modify flags for an existing section, we create a new
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// section with the right flags, and use 0 as the unique ID for
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// execute-only text
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TextSection =
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Ctx.getELFSection(".text", Type, Flags, 0, "", false, 0U, nullptr);
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}
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}
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MCRegister ARMElfTargetObjectFile::getStaticBase() const { return ARM::R9; }
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const MCExpr *ARMElfTargetObjectFile::
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getIndirectSymViaRWPI(const MCSymbol *Sym) const {
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return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_ARM_SBREL,
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getContext());
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}
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const MCExpr *ARMElfTargetObjectFile::getTTypeGlobalReference(
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const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM,
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MachineModuleInfo *MMI, MCStreamer &Streamer) const {
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if (TM.getMCAsmInfo()->getExceptionHandlingType() != ExceptionHandling::ARM)
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return TargetLoweringObjectFileELF::getTTypeGlobalReference(
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GV, Encoding, TM, MMI, Streamer);
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assert(Encoding == DW_EH_PE_absptr && "Can handle absptr encoding only");
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return MCSymbolRefExpr::create(TM.getSymbol(GV),
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MCSymbolRefExpr::VK_ARM_TARGET2, getContext());
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}
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const MCExpr *ARMElfTargetObjectFile::
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getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
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return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_ARM_TLSLDO,
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getContext());
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}
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static bool isExecuteOnlyFunction(const GlobalObject *GO, SectionKind SK,
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const TargetMachine &TM) {
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if (const Function *F = dyn_cast<Function>(GO))
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if (TM.getSubtarget<ARMSubtarget>(*F).genExecuteOnly() && SK.isText())
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return true;
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return false;
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}
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MCSection *ARMElfTargetObjectFile::getExplicitSectionGlobal(
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const GlobalObject *GO, SectionKind SK, const TargetMachine &TM) const {
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// Set execute-only access for the explicit section
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if (isExecuteOnlyFunction(GO, SK, TM))
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SK = SectionKind::getExecuteOnly();
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return TargetLoweringObjectFileELF::getExplicitSectionGlobal(GO, SK, TM);
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}
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MCSection *ARMElfTargetObjectFile::SelectSectionForGlobal(
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const GlobalObject *GO, SectionKind SK, const TargetMachine &TM) const {
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// Place the global in the execute-only text section
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if (isExecuteOnlyFunction(GO, SK, TM))
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SK = SectionKind::getExecuteOnly();
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return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, SK, TM);
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}
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