1 //===- AMDGPUELFObjectWriter.cpp - AMDGPU ELF Writer ----------------------===//
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 "AMDGPUFixupKinds.h"
10 #include "AMDGPUMCTargetDesc.h"
11 #include "llvm/MC/MCContext.h"
12 #include "llvm/MC/MCELFObjectWriter.h"
13 #include "llvm/MC/MCValue.h"
14
15 using namespace llvm;
16
17 namespace {
18
19 class AMDGPUELFObjectWriter : public MCELFObjectTargetWriter {
20 public:
21 AMDGPUELFObjectWriter(bool Is64Bit, uint8_t OSABI, bool HasRelocationAddend);
22
23 protected:
24 unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
25 const MCFixup &Fixup, bool IsPCRel) const override;
26 };
27
28
29 } // end anonymous namespace
30
AMDGPUELFObjectWriter(bool Is64Bit,uint8_t OSABI,bool HasRelocationAddend)31 AMDGPUELFObjectWriter::AMDGPUELFObjectWriter(bool Is64Bit, uint8_t OSABI,
32 bool HasRelocationAddend)
33 : MCELFObjectTargetWriter(Is64Bit, OSABI, ELF::EM_AMDGPU,
34 HasRelocationAddend) {}
35
getRelocType(MCContext & Ctx,const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const36 unsigned AMDGPUELFObjectWriter::getRelocType(MCContext &Ctx,
37 const MCValue &Target,
38 const MCFixup &Fixup,
39 bool IsPCRel) const {
40 if (const auto *SymA = Target.getSymA()) {
41 // SCRATCH_RSRC_DWORD[01] is a special global variable that represents
42 // the scratch buffer.
43 if (SymA->getSymbol().getName() == "SCRATCH_RSRC_DWORD0" ||
44 SymA->getSymbol().getName() == "SCRATCH_RSRC_DWORD1")
45 return ELF::R_AMDGPU_ABS32_LO;
46 }
47
48 switch (Target.getAccessVariant()) {
49 default:
50 break;
51 case MCSymbolRefExpr::VK_GOTPCREL:
52 return ELF::R_AMDGPU_GOTPCREL;
53 case MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_LO:
54 return ELF::R_AMDGPU_GOTPCREL32_LO;
55 case MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_HI:
56 return ELF::R_AMDGPU_GOTPCREL32_HI;
57 case MCSymbolRefExpr::VK_AMDGPU_REL32_LO:
58 return ELF::R_AMDGPU_REL32_LO;
59 case MCSymbolRefExpr::VK_AMDGPU_REL32_HI:
60 return ELF::R_AMDGPU_REL32_HI;
61 case MCSymbolRefExpr::VK_AMDGPU_REL64:
62 return ELF::R_AMDGPU_REL64;
63 case MCSymbolRefExpr::VK_AMDGPU_ABS32_LO:
64 return ELF::R_AMDGPU_ABS32_LO;
65 case MCSymbolRefExpr::VK_AMDGPU_ABS32_HI:
66 return ELF::R_AMDGPU_ABS32_HI;
67 }
68
69 MCFixupKind Kind = Fixup.getKind();
70 if (Kind >= FirstLiteralRelocationKind)
71 return Kind - FirstLiteralRelocationKind;
72 switch (Kind) {
73 default: break;
74 case FK_PCRel_4:
75 return ELF::R_AMDGPU_REL32;
76 case FK_Data_4:
77 case FK_SecRel_4:
78 return IsPCRel ? ELF::R_AMDGPU_REL32 : ELF::R_AMDGPU_ABS32;
79 case FK_Data_8:
80 return IsPCRel ? ELF::R_AMDGPU_REL64 : ELF::R_AMDGPU_ABS64;
81 }
82
83 if (Fixup.getTargetKind() == AMDGPU::fixup_si_sopp_br) {
84 const auto *SymA = Target.getSymA();
85 assert(SymA);
86
87 if (SymA->getSymbol().isUndefined()) {
88 Ctx.reportError(Fixup.getLoc(), Twine("undefined label '") +
89 SymA->getSymbol().getName() + "'");
90 return ELF::R_AMDGPU_NONE;
91 }
92 return ELF::R_AMDGPU_REL16;
93 }
94
95 llvm_unreachable("unhandled relocation type");
96 }
97
98 std::unique_ptr<MCObjectTargetWriter>
createAMDGPUELFObjectWriter(bool Is64Bit,uint8_t OSABI,bool HasRelocationAddend)99 llvm::createAMDGPUELFObjectWriter(bool Is64Bit, uint8_t OSABI,
100 bool HasRelocationAddend) {
101 return std::make_unique<AMDGPUELFObjectWriter>(Is64Bit, OSABI,
102 HasRelocationAddend);
103 }
104