lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp

   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 "AMDGPUMCTargetDesc.h"
  10 #include "llvm/BinaryFormat/ELF.h"
  11 #include "llvm/MC/MCELFObjectWriter.h"
  12 #include "llvm/MC/MCExpr.h"
  13 #include "llvm/MC/MCFixup.h"
  14 #include "llvm/MC/MCObjectWriter.h"
  15 #include "llvm/MC/MCSymbol.h"
  16 #include "llvm/MC/MCValue.h"
  17 #include "llvm/Support/ErrorHandling.h"
  18
  19 using namespace llvm;
  20
  21 namespace {
  22
  23 class AMDGPUELFObjectWriter : public MCELFObjectTargetWriter {
  24 public:
  25   AMDGPUELFObjectWriter(bool Is64Bit, uint8_t OSABI, bool HasRelocationAddend,
  26                         uint8_t ABIVersion);
  27
  28 protected:
  29   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
  30                         const MCFixup &Fixup, bool IsPCRel) const override;
  31 };
  32
  33
  34 } // end anonymous namespace
  35
  36 AMDGPUELFObjectWriter::AMDGPUELFObjectWriter(bool Is64Bit,
  37                                              uint8_t OSABI,
  38                                              bool HasRelocationAddend,
  39                                              uint8_t ABIVersion)
  40   : MCELFObjectTargetWriter(Is64Bit, OSABI, ELF::EM_AMDGPU,
  41                             HasRelocationAddend, ABIVersion) {}
  42
  43 unsigned AMDGPUELFObjectWriter::getRelocType(MCContext &Ctx,
  44                                              const MCValue &Target,
  45                                              const MCFixup &Fixup,
  46                                              bool IsPCRel) const {
  47   if (const auto *SymA = Target.getSymA()) {
  48     // SCRATCH_RSRC_DWORD[01] is a special global variable that represents
  49     // the scratch buffer.
  50     if (SymA->getSymbol().getName() == "SCRATCH_RSRC_DWORD0" ||
  51         SymA->getSymbol().getName() == "SCRATCH_RSRC_DWORD1")
  52       return ELF::R_AMDGPU_ABS32_LO;
  53   }
  54
  55   switch (Target.getAccessVariant()) {
  56   default:
  57     break;
  58   case MCSymbolRefExpr::VK_GOTPCREL:
  59     return ELF::R_AMDGPU_GOTPCREL;
  60   case MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_LO:
  61     return ELF::R_AMDGPU_GOTPCREL32_LO;
  62   case MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_HI:
  63     return ELF::R_AMDGPU_GOTPCREL32_HI;
  64   case MCSymbolRefExpr::VK_AMDGPU_REL32_LO:
  65     return ELF::R_AMDGPU_REL32_LO;
  66   case MCSymbolRefExpr::VK_AMDGPU_REL32_HI:
  67     return ELF::R_AMDGPU_REL32_HI;
  68   case MCSymbolRefExpr::VK_AMDGPU_REL64:
  69     return ELF::R_AMDGPU_REL64;
  70   }
  71
  72   switch (Fixup.getKind()) {
  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 ELF::R_AMDGPU_ABS32;
  79   case FK_Data_8:
  80     return ELF::R_AMDGPU_ABS64;
  81   }
  82
  83   llvm_unreachable("unhandled relocation type");
  84 }
  85
  86 std::unique_ptr<MCObjectTargetWriter>
  87 llvm::createAMDGPUELFObjectWriter(bool Is64Bit, uint8_t OSABI,
  88                                   bool HasRelocationAddend,
  89                                   uint8_t ABIVersion) {
  90   return std::make_unique<AMDGPUELFObjectWriter>(Is64Bit, OSABI,
  91                                                   HasRelocationAddend,
  92                                                   ABIVersion);
  93 }