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