| //===-- llvm/Target/ARMTargetObjectFile.cpp - ARM Object Info Impl --------===// |
| // |
| // 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 "ARMTargetObjectFile.h" |
| #include "ARMSubtarget.h" |
| #include "ARMTargetMachine.h" |
| #include "llvm/BinaryFormat/Dwarf.h" |
| #include "llvm/BinaryFormat/ELF.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/Target/TargetMachine.h" |
| #include <cassert> |
| |
| using namespace llvm; |
| using namespace dwarf; |
| |
| //===----------------------------------------------------------------------===// |
| // ELF Target |
| //===----------------------------------------------------------------------===// |
| |
| void ARMElfTargetObjectFile::Initialize(MCContext &Ctx, |
| const TargetMachine &TM) { |
| const ARMBaseTargetMachine &ARM_TM = static_cast<const ARMBaseTargetMachine &>(TM); |
| bool isAAPCS_ABI = ARM_TM.TargetABI == ARMBaseTargetMachine::ARMABI::ARM_ABI_AAPCS; |
| bool genExecuteOnly = |
| ARM_TM.getMCSubtargetInfo()->hasFeature(ARM::FeatureExecuteOnly); |
| |
| TargetLoweringObjectFileELF::Initialize(Ctx, TM); |
| InitializeELF(isAAPCS_ABI); |
| |
| if (isAAPCS_ABI) { |
| LSDASection = nullptr; |
| } |
| |
| // 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, "", false, 0U, nullptr); |
| } |
| } |
| |
| const MCRegister ARMElfTargetObjectFile::getStaticBase() const { |
| return ARM::R9; |
| } |
| |
| const MCExpr *ARMElfTargetObjectFile:: |
| getIndirectSymViaRWPI(const MCSymbol *Sym) const { |
| return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_ARM_SBREL, |
| getContext()); |
| } |
| |
| 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()); |
| } |
| |
| static bool isExecuteOnlyFunction(const GlobalObject *GO, SectionKind SK, |
| const TargetMachine &TM) { |
| if (const Function *F = dyn_cast<Function>(GO)) |
| if (TM.getSubtarget<ARMSubtarget>(*F).genExecuteOnly() && SK.isText()) |
| return true; |
| return false; |
| } |
| |
| MCSection *ARMElfTargetObjectFile::getExplicitSectionGlobal( |
| const GlobalObject *GO, SectionKind SK, const TargetMachine &TM) const { |
| // Set execute-only access for the explicit section |
| if (isExecuteOnlyFunction(GO, SK, TM)) |
| 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 (isExecuteOnlyFunction(GO, SK, TM)) |
| SK = SectionKind::getExecuteOnly(); |
| |
| return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, SK, TM); |
| } |