ARMWinCOFFObjectWriter.cpp revision 360784 
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
23using namespace llvm;
24
25namespace {
26
27class ARMWinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
28public:
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
45unsigned 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
87bool ARMWinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
88  return static_cast<unsigned>(Fixup.getKind()) != ARM::fixup_t2_movt_hi16;
89}
90
91namespace llvm {
92
93std::unique_ptr<MCObjectTargetWriter>
94createARMWinCOFFObjectWriter(bool Is64Bit) {
95  return std::make_unique<ARMWinCOFFObjectWriter>(Is64Bit);
96}
97
98} // end namespace llvm
99