1 //===-- AArch64TargetObjectFile.cpp - AArch64 Object Info -----------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "AArch64TargetObjectFile.h" 10 #include "AArch64TargetMachine.h" 11 #include "llvm/BinaryFormat/Dwarf.h" 12 #include "llvm/IR/Mangler.h" 13 #include "llvm/MC/MCContext.h" 14 #include "llvm/MC/MCExpr.h" 15 #include "llvm/MC/MCStreamer.h" 16 #include "llvm/MC/MCValue.h" 17 using namespace llvm; 18 using namespace dwarf; 19 20 void AArch64_ELFTargetObjectFile::Initialize(MCContext &Ctx, 21 const TargetMachine &TM) { 22 TargetLoweringObjectFileELF::Initialize(Ctx, TM); 23 // AARCH64 ELF ABI does not define static relocation type for TLS offset 24 // within a module. Do not generate AT_location for TLS variables. 25 SupportDebugThreadLocalLocation = false; 26 } 27 28 const MCExpr *AArch64_ELFTargetObjectFile::getIndirectSymViaGOTPCRel( 29 const GlobalValue *GV, const MCSymbol *Sym, const MCValue &MV, 30 int64_t Offset, MachineModuleInfo *MMI, MCStreamer &Streamer) const { 31 int64_t FinalOffset = Offset + MV.getConstant(); 32 const MCExpr *Res = 33 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext()); 34 const MCExpr *Off = MCConstantExpr::create(FinalOffset, getContext()); 35 return MCBinaryExpr::createAdd(Res, Off, getContext()); 36 } 37 38 AArch64_MachoTargetObjectFile::AArch64_MachoTargetObjectFile() { 39 SupportGOTPCRelWithOffset = false; 40 } 41 42 const MCExpr *AArch64_MachoTargetObjectFile::getTTypeGlobalReference( 43 const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM, 44 MachineModuleInfo *MMI, MCStreamer &Streamer) const { 45 // On Darwin, we can reference dwarf symbols with foo@GOT-., which 46 // is an indirect pc-relative reference. The default implementation 47 // won't reference using the GOT, so we need this target-specific 48 // version. 49 if (Encoding & (DW_EH_PE_indirect | DW_EH_PE_pcrel)) { 50 const MCSymbol *Sym = TM.getSymbol(GV); 51 const MCExpr *Res = 52 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOT, getContext()); 53 MCSymbol *PCSym = getContext().createTempSymbol(); 54 Streamer.emitLabel(PCSym); 55 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, getContext()); 56 return MCBinaryExpr::createSub(Res, PC, getContext()); 57 } 58 59 return TargetLoweringObjectFileMachO::getTTypeGlobalReference( 60 GV, Encoding, TM, MMI, Streamer); 61 } 62 63 MCSymbol *AArch64_MachoTargetObjectFile::getCFIPersonalitySymbol( 64 const GlobalValue *GV, const TargetMachine &TM, 65 MachineModuleInfo *MMI) const { 66 return TM.getSymbol(GV); 67 } 68 69 const MCExpr *AArch64_MachoTargetObjectFile::getIndirectSymViaGOTPCRel( 70 const GlobalValue *GV, const MCSymbol *Sym, const MCValue &MV, 71 int64_t Offset, MachineModuleInfo *MMI, MCStreamer &Streamer) const { 72 assert((Offset+MV.getConstant() == 0) && 73 "Arch64 does not support GOT PC rel with extra offset"); 74 // On ARM64 Darwin, we can reference symbols with foo@GOT-., which 75 // is an indirect pc-relative reference. 76 const MCExpr *Res = 77 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOT, getContext()); 78 MCSymbol *PCSym = getContext().createTempSymbol(); 79 Streamer.emitLabel(PCSym); 80 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, getContext()); 81 return MCBinaryExpr::createSub(Res, PC, getContext()); 82 } 83 84 void AArch64_MachoTargetObjectFile::getNameWithPrefix( 85 SmallVectorImpl<char> &OutName, const GlobalValue *GV, 86 const TargetMachine &TM) const { 87 // AArch64 does not use section-relative relocations so any global symbol must 88 // be accessed via at least a linker-private symbol. 89 getMangler().getNameWithPrefix(OutName, GV, /* CannotUsePrivateLabel */ true); 90 } 91