1 //===- MCAsmBackend.cpp - Target MC Assembly Backend ----------------------===//
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 "llvm/MC/MCAsmBackend.h"
10 #include "llvm/ADT/None.h"
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/MC/MCELFObjectWriter.h"
13 #include "llvm/MC/MCFixupKindInfo.h"
14 #include "llvm/MC/MCMachObjectWriter.h"
15 #include "llvm/MC/MCObjectWriter.h"
16 #include "llvm/MC/MCWasmObjectWriter.h"
17 #include "llvm/MC/MCWinCOFFObjectWriter.h"
18 #include "llvm/MC/MCXCOFFObjectWriter.h"
19 #include <cassert>
20 #include <cstddef>
21 #include <cstdint>
22
23 using namespace llvm;
24
MCAsmBackend(support::endianness Endian)25 MCAsmBackend::MCAsmBackend(support::endianness Endian) : Endian(Endian) {}
26
27 MCAsmBackend::~MCAsmBackend() = default;
28
29 std::unique_ptr<MCObjectWriter>
createObjectWriter(raw_pwrite_stream & OS) const30 MCAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
31 auto TW = createObjectTargetWriter();
32 switch (TW->getFormat()) {
33 case Triple::ELF:
34 return createELFObjectWriter(cast<MCELFObjectTargetWriter>(std::move(TW)), OS,
35 Endian == support::little);
36 case Triple::MachO:
37 return createMachObjectWriter(cast<MCMachObjectTargetWriter>(std::move(TW)),
38 OS, Endian == support::little);
39 case Triple::COFF:
40 return createWinCOFFObjectWriter(
41 cast<MCWinCOFFObjectTargetWriter>(std::move(TW)), OS);
42 case Triple::Wasm:
43 return createWasmObjectWriter(cast<MCWasmObjectTargetWriter>(std::move(TW)),
44 OS);
45 case Triple::XCOFF:
46 return createXCOFFObjectWriter(
47 cast<MCXCOFFObjectTargetWriter>(std::move(TW)), OS);
48 default:
49 llvm_unreachable("unexpected object format");
50 }
51 }
52
53 std::unique_ptr<MCObjectWriter>
createDwoObjectWriter(raw_pwrite_stream & OS,raw_pwrite_stream & DwoOS) const54 MCAsmBackend::createDwoObjectWriter(raw_pwrite_stream &OS,
55 raw_pwrite_stream &DwoOS) const {
56 auto TW = createObjectTargetWriter();
57 if (TW->getFormat() != Triple::ELF)
58 report_fatal_error("dwo only supported with ELF");
59 return createELFDwoObjectWriter(cast<MCELFObjectTargetWriter>(std::move(TW)),
60 OS, DwoOS, Endian == support::little);
61 }
62
getFixupKind(StringRef Name) const63 Optional<MCFixupKind> MCAsmBackend::getFixupKind(StringRef Name) const {
64 return None;
65 }
66
getFixupKindInfo(MCFixupKind Kind) const67 const MCFixupKindInfo &MCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
68 static const MCFixupKindInfo Builtins[] = {
69 {"FK_NONE", 0, 0, 0},
70 {"FK_Data_1", 0, 8, 0},
71 {"FK_Data_2", 0, 16, 0},
72 {"FK_Data_4", 0, 32, 0},
73 {"FK_Data_8", 0, 64, 0},
74 {"FK_Data_6b", 0, 6, 0},
75 {"FK_PCRel_1", 0, 8, MCFixupKindInfo::FKF_IsPCRel},
76 {"FK_PCRel_2", 0, 16, MCFixupKindInfo::FKF_IsPCRel},
77 {"FK_PCRel_4", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
78 {"FK_PCRel_8", 0, 64, MCFixupKindInfo::FKF_IsPCRel},
79 {"FK_GPRel_1", 0, 8, 0},
80 {"FK_GPRel_2", 0, 16, 0},
81 {"FK_GPRel_4", 0, 32, 0},
82 {"FK_GPRel_8", 0, 64, 0},
83 {"FK_DTPRel_4", 0, 32, 0},
84 {"FK_DTPRel_8", 0, 64, 0},
85 {"FK_TPRel_4", 0, 32, 0},
86 {"FK_TPRel_8", 0, 64, 0},
87 {"FK_SecRel_1", 0, 8, 0},
88 {"FK_SecRel_2", 0, 16, 0},
89 {"FK_SecRel_4", 0, 32, 0},
90 {"FK_SecRel_8", 0, 64, 0},
91 {"FK_Data_Add_1", 0, 8, 0},
92 {"FK_Data_Add_2", 0, 16, 0},
93 {"FK_Data_Add_4", 0, 32, 0},
94 {"FK_Data_Add_8", 0, 64, 0},
95 {"FK_Data_Add_6b", 0, 6, 0},
96 {"FK_Data_Sub_1", 0, 8, 0},
97 {"FK_Data_Sub_2", 0, 16, 0},
98 {"FK_Data_Sub_4", 0, 32, 0},
99 {"FK_Data_Sub_8", 0, 64, 0},
100 {"FK_Data_Sub_6b", 0, 6, 0}};
101
102 assert((size_t)Kind <= array_lengthof(Builtins) && "Unknown fixup kind");
103 return Builtins[Kind];
104 }
105
fixupNeedsRelaxationAdvanced(const MCFixup & Fixup,bool Resolved,uint64_t Value,const MCRelaxableFragment * DF,const MCAsmLayout & Layout,const bool WasForced) const106 bool MCAsmBackend::fixupNeedsRelaxationAdvanced(
107 const MCFixup &Fixup, bool Resolved, uint64_t Value,
108 const MCRelaxableFragment *DF, const MCAsmLayout &Layout,
109 const bool WasForced) const {
110 if (!Resolved)
111 return true;
112 return fixupNeedsRelaxation(Fixup, Value, DF, Layout);
113 }
114