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 InitializeELF(TM.Options.UseInitArray); 24 // AARCH64 ELF ABI does not define static relocation type for TLS offset 25 // within a module. Do not generate AT_location for TLS variables. 26 SupportDebugThreadLocalLocation = false; 27 } 28 29 AArch64_MachoTargetObjectFile::AArch64_MachoTargetObjectFile() 30 : TargetLoweringObjectFileMachO() { 31 SupportGOTPCRelWithOffset = false; 32 } 33 34 const MCExpr *AArch64_MachoTargetObjectFile::getTTypeGlobalReference( 35 const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM, 36 MachineModuleInfo *MMI, MCStreamer &Streamer) const { 37 // On Darwin, we can reference dwarf symbols with foo@GOT-., which 38 // is an indirect pc-relative reference. The default implementation 39 // won't reference using the GOT, so we need this target-specific 40 // version. 41 if (Encoding & (DW_EH_PE_indirect | DW_EH_PE_pcrel)) { 42 const MCSymbol *Sym = TM.getSymbol(GV); 43 const MCExpr *Res = 44 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOT, getContext()); 45 MCSymbol *PCSym = getContext().createTempSymbol(); 46 Streamer.EmitLabel(PCSym); 47 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, getContext()); 48 return MCBinaryExpr::createSub(Res, PC, getContext()); 49 } 50 51 return TargetLoweringObjectFileMachO::getTTypeGlobalReference( 52 GV, Encoding, TM, MMI, Streamer); 53 } 54 55 MCSymbol *AArch64_MachoTargetObjectFile::getCFIPersonalitySymbol( 56 const GlobalValue *GV, const TargetMachine &TM, 57 MachineModuleInfo *MMI) const { 58 return TM.getSymbol(GV); 59 } 60 61 const MCExpr *AArch64_MachoTargetObjectFile::getIndirectSymViaGOTPCRel( 62 const MCSymbol *Sym, const MCValue &MV, int64_t Offset, 63 MachineModuleInfo *MMI, MCStreamer &Streamer) const { 64 assert((Offset+MV.getConstant() == 0) && 65 "Arch64 does not support GOT PC rel with extra offset"); 66 // On ARM64 Darwin, we can reference symbols with foo@GOT-., which 67 // is an indirect pc-relative reference. 68 const MCExpr *Res = 69 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOT, getContext()); 70 MCSymbol *PCSym = getContext().createTempSymbol(); 71 Streamer.EmitLabel(PCSym); 72 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, getContext()); 73 return MCBinaryExpr::createSub(Res, PC, getContext()); 74 } 75 76 void AArch64_MachoTargetObjectFile::getNameWithPrefix( 77 SmallVectorImpl<char> &OutName, const GlobalValue *GV, 78 const TargetMachine &TM) const { 79 // AArch64 does not use section-relative relocations so any global symbol must 80 // be accessed via at least a linker-private symbol. 81 getMangler().getNameWithPrefix(OutName, GV, /* CannotUsePrivateLabel */ true); 82 } 83