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
23using namespace llvm;
24
25namespace {
26
27class ARMWinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
28public:
29  ARMWinCOFFObjectWriter()
30    : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARMNT) {
31  }
32
33  ~ARMWinCOFFObjectWriter() override = default;
34
35  unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
36                        const MCFixup &Fixup, bool IsCrossSection,
37                        const MCAsmBackend &MAB) const override;
38
39  bool recordRelocation(const MCFixup &) const override;
40};
41
42} // end anonymous namespace
43
44unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
45                                              const MCValue &Target,
46                                              const MCFixup &Fixup,
47                                              bool IsCrossSection,
48                                              const MCAsmBackend &MAB) const {
49  MCSymbolRefExpr::VariantKind Modifier =
50    Target.isAbsolute() ? MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
51
52  unsigned FixupKind = Fixup.getKind();
53  if (IsCrossSection) {
54    if (FixupKind != FK_Data_4) {
55      Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
56      return COFF::IMAGE_REL_ARM_ADDR32;
57    }
58    FixupKind = FK_PCRel_4;
59  }
60
61
62  switch (FixupKind) {
63  default: {
64    const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
65    report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
66  }
67  case FK_Data_4:
68    switch (Modifier) {
69    case MCSymbolRefExpr::VK_COFF_IMGREL32:
70      return COFF::IMAGE_REL_ARM_ADDR32NB;
71    case MCSymbolRefExpr::VK_SECREL:
72      return COFF::IMAGE_REL_ARM_SECREL;
73    default:
74      return COFF::IMAGE_REL_ARM_ADDR32;
75    }
76  case FK_PCRel_4:
77    return COFF::IMAGE_REL_ARM_REL32;
78  case FK_SecRel_2:
79    return COFF::IMAGE_REL_ARM_SECTION;
80  case FK_SecRel_4:
81    return COFF::IMAGE_REL_ARM_SECREL;
82  case ARM::fixup_t2_condbranch:
83    return COFF::IMAGE_REL_ARM_BRANCH20T;
84  case ARM::fixup_t2_uncondbranch:
85  case ARM::fixup_arm_thumb_bl:
86    return COFF::IMAGE_REL_ARM_BRANCH24T;
87  case ARM::fixup_arm_thumb_blx:
88    return COFF::IMAGE_REL_ARM_BLX23T;
89  case ARM::fixup_t2_movw_lo16:
90  case ARM::fixup_t2_movt_hi16:
91    return COFF::IMAGE_REL_ARM_MOV32T;
92  }
93}
94
95bool ARMWinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
96  return static_cast<unsigned>(Fixup.getKind()) != ARM::fixup_t2_movt_hi16;
97}
98
99namespace llvm {
100
101std::unique_ptr<MCObjectTargetWriter>
102createARMWinCOFFObjectWriter() {
103  return std::make_unique<ARMWinCOFFObjectWriter>();
104}
105
106} // end namespace llvm
107