xref: /freebsd/contrib/llvm-project/llvm/lib/Target/AArch64/AArch64TargetObjectFile.cpp (revision 7877fdebeeb35fad1cbbafce22598b1bdf97c786)
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