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