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/MCObjectWriter.h"
  17 #include "llvm/MC/MCValue.h"
  18 #include "llvm/MC/MCWinCOFFObjectWriter.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20
  21 using namespace llvm;
  22
  23 namespace {
  24
  25 class ARMWinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
  26 public:
  27   ARMWinCOFFObjectWriter()
  28     : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARMNT) {
  29   }
  30
  31   ~ARMWinCOFFObjectWriter() override = default;
  32
  33   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
  34                         const MCFixup &Fixup, bool IsCrossSection,
  35                         const MCAsmBackend &MAB) const override;
  36
  37   bool recordRelocation(const MCFixup &) const override;
  38 };
  39
  40 } // end anonymous namespace
  41
  42 unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
  43                                               const MCValue &Target,
  44                                               const MCFixup &Fixup,
  45                                               bool IsCrossSection,
  46                                               const MCAsmBackend &MAB) const {
  47   MCSymbolRefExpr::VariantKind Modifier =
  48     Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
  49
  50   unsigned FixupKind = Fixup.getKind();
  51   if (IsCrossSection) {
  52     if (FixupKind != FK_Data_4) {
  53       Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
  54       return COFF::IMAGE_REL_ARM_ADDR32;
  55     }
  56     FixupKind = FK_PCRel_4;
  57   }
  58
  59
  60   switch (FixupKind) {
  61   default: {
  62     Ctx.reportError(Fixup.getLoc(), "unsupported relocation type");
  63     return COFF::IMAGE_REL_ARM_ABSOLUTE;
  64   }
  65   case FK_Data_4:
  66     switch (Modifier) {
  67     case MCSymbolRefExpr::VK_COFF_IMGREL32:
  68       return COFF::IMAGE_REL_ARM_ADDR32NB;
  69     case MCSymbolRefExpr::VK_SECREL:
  70       return COFF::IMAGE_REL_ARM_SECREL;
  71     default:
  72       return COFF::IMAGE_REL_ARM_ADDR32;
  73     }
  74   case FK_PCRel_4:
  75     return COFF::IMAGE_REL_ARM_REL32;
  76   case FK_SecRel_2:
  77     return COFF::IMAGE_REL_ARM_SECTION;
  78   case FK_SecRel_4:
  79     return COFF::IMAGE_REL_ARM_SECREL;
  80   case ARM::fixup_t2_condbranch:
  81     return COFF::IMAGE_REL_ARM_BRANCH20T;
  82   case ARM::fixup_t2_uncondbranch:
  83   case ARM::fixup_arm_thumb_bl:
  84     return COFF::IMAGE_REL_ARM_BRANCH24T;
  85   case ARM::fixup_arm_thumb_blx:
  86     return COFF::IMAGE_REL_ARM_BLX23T;
  87   case ARM::fixup_t2_movw_lo16:
  88   case ARM::fixup_t2_movt_hi16:
  89     return COFF::IMAGE_REL_ARM_MOV32T;
  90   }
  91 }
  92
  93 bool ARMWinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
  94   return static_cast<unsigned>(Fixup.getKind()) != ARM::fixup_t2_movt_hi16;
  95 }
  96
  97 namespace llvm {
  98
  99 std::unique_ptr<MCObjectTargetWriter>
 100 createARMWinCOFFObjectWriter() {
 101   return std::make_unique<ARMWinCOFFObjectWriter>();
 102 }
 103
 104 } // end namespace llvm