llvm/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/MCContext.h"
  14 #include "llvm/MC/MCExpr.h"
  15 #include "llvm/MC/MCFixup.h"
  16 #include "llvm/MC/MCFixupKindInfo.h"
  17 #include "llvm/MC/MCObjectWriter.h"
  18 #include "llvm/MC/MCValue.h"
  19 #include "llvm/MC/MCWinCOFFObjectWriter.h"
  20 #include "llvm/Support/ErrorHandling.h"
  21 #include "llvm/Support/raw_ostream.h"
  22 #include <cassert>
  23
  24 using namespace llvm;
  25
  26 namespace {
  27
  28 class ARMWinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
  29 public:
  30   ARMWinCOFFObjectWriter()
  31     : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARMNT) {
  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   MCSymbolRefExpr::VariantKind Modifier =
  51     Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
  52
  53   unsigned FixupKind = Fixup.getKind();
  54   if (IsCrossSection) {
  55     if (FixupKind != FK_Data_4) {
  56       Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
  57       return COFF::IMAGE_REL_ARM_ADDR32;
  58     }
  59     FixupKind = FK_PCRel_4;
  60   }
  61
  62
  63   switch (FixupKind) {
  64   default: {
  65     const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
  66     report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
  67   }
  68   case FK_Data_4:
  69     switch (Modifier) {
  70     case MCSymbolRefExpr::VK_COFF_IMGREL32:
  71       return COFF::IMAGE_REL_ARM_ADDR32NB;
  72     case MCSymbolRefExpr::VK_SECREL:
  73       return COFF::IMAGE_REL_ARM_SECREL;
  74     default:
  75       return COFF::IMAGE_REL_ARM_ADDR32;
  76     }
  77   case FK_PCRel_4:
  78     return COFF::IMAGE_REL_ARM_REL32;
  79   case FK_SecRel_2:
  80     return COFF::IMAGE_REL_ARM_SECTION;
  81   case FK_SecRel_4:
  82     return COFF::IMAGE_REL_ARM_SECREL;
  83   case ARM::fixup_t2_condbranch:
  84     return COFF::IMAGE_REL_ARM_BRANCH20T;
  85   case ARM::fixup_t2_uncondbranch:
  86   case ARM::fixup_arm_thumb_bl:
  87     return COFF::IMAGE_REL_ARM_BRANCH24T;
  88   case ARM::fixup_arm_thumb_blx:
  89     return COFF::IMAGE_REL_ARM_BLX23T;
  90   case ARM::fixup_t2_movw_lo16:
  91   case ARM::fixup_t2_movt_hi16:
  92     return COFF::IMAGE_REL_ARM_MOV32T;
  93   }
  94 }
  95
  96 bool ARMWinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
  97   return static_cast<unsigned>(Fixup.getKind()) != ARM::fixup_t2_movt_hi16;
  98 }
  99
 100 namespace llvm {
 101
 102 std::unique_ptr<MCObjectTargetWriter>
 103 createARMWinCOFFObjectWriter() {
 104   return std::make_unique<ARMWinCOFFObjectWriter>();
 105 }
 106
 107 } // end namespace llvm