lib/Target/ARM/MCTargetDesc/ARMWinCOFFObjectWriter.cpp

   1 //===-- ARMWinCOFFObjectWriter.cpp - ARM Windows COFF Object Writer -- C++ -==//
   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 "MCTargetDesc/ARMFixupKinds.h"
  10 #include "llvm/ADT/Twine.h"
  11 #include "llvm/BinaryFormat/COFF.h"
  12 #include "llvm/MC/MCAsmBackend.h"
  13 #include "llvm/MC/MCExpr.h"
  14 #include "llvm/MC/MCFixup.h"
  15 #include "llvm/MC/MCFixupKindInfo.h"
  16 #include "llvm/MC/MCObjectWriter.h"
  17 #include "llvm/MC/MCValue.h"
  18 #include "llvm/MC/MCWinCOFFObjectWriter.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 #include <cassert>
  22
  23 using namespace llvm;
  24
  25 namespace {
  26
  27 class ARMWinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
  28 public:
  29   ARMWinCOFFObjectWriter(bool Is64Bit)
  30     : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARMNT) {
  31     assert(!Is64Bit && "AArch64 support not yet implemented");
  32   }
  33
  34   ~ARMWinCOFFObjectWriter() override = default;
  35
  36   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
  37                         const MCFixup &Fixup, bool IsCrossSection,
  38                         const MCAsmBackend &MAB) const override;
  39
  40   bool recordRelocation(const MCFixup &) const override;
  41 };
  42
  43 } // end anonymous namespace
  44
  45 unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
  46                                               const MCValue &Target,
  47                                               const MCFixup &Fixup,
  48                                               bool IsCrossSection,
  49                                               const MCAsmBackend &MAB) const {
  50   assert(getMachine() == COFF::IMAGE_FILE_MACHINE_ARMNT &&
  51          "AArch64 support not yet implemented");
  52
  53   MCSymbolRefExpr::VariantKind Modifier =
  54     Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
  55
  56   switch (static_cast<unsigned>(Fixup.getKind())) {
  57   default: {
  58     const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
  59     report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
  60   }
  61   case FK_Data_4:
  62     switch (Modifier) {
  63     case MCSymbolRefExpr::VK_COFF_IMGREL32:
  64       return COFF::IMAGE_REL_ARM_ADDR32NB;
  65     case MCSymbolRefExpr::VK_SECREL:
  66       return COFF::IMAGE_REL_ARM_SECREL;
  67     default:
  68       return COFF::IMAGE_REL_ARM_ADDR32;
  69     }
  70   case FK_SecRel_2:
  71     return COFF::IMAGE_REL_ARM_SECTION;
  72   case FK_SecRel_4:
  73     return COFF::IMAGE_REL_ARM_SECREL;
  74   case ARM::fixup_t2_condbranch:
  75     return COFF::IMAGE_REL_ARM_BRANCH20T;
  76   case ARM::fixup_t2_uncondbranch:
  77   case ARM::fixup_arm_thumb_bl:
  78     return COFF::IMAGE_REL_ARM_BRANCH24T;
  79   case ARM::fixup_arm_thumb_blx:
  80     return COFF::IMAGE_REL_ARM_BLX23T;
  81   case ARM::fixup_t2_movw_lo16:
  82   case ARM::fixup_t2_movt_hi16:
  83     return COFF::IMAGE_REL_ARM_MOV32T;
  84   }
  85 }
  86
  87 bool ARMWinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
  88   return static_cast<unsigned>(Fixup.getKind()) != ARM::fixup_t2_movt_hi16;
  89 }
  90
  91 namespace llvm {
  92
  93 std::unique_ptr<MCObjectTargetWriter>
  94 createARMWinCOFFObjectWriter(bool Is64Bit) {
  95   return llvm::make_unique<ARMWinCOFFObjectWriter>(Is64Bit);
  96 }
  97
  98 } // end namespace llvm