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/MC/MCDXContainerWriter.h"
11#include "llvm/MC/MCELFObjectWriter.h"
12#include "llvm/MC/MCFixupKindInfo.h"
13#include "llvm/MC/MCGOFFObjectWriter.h"
14#include "llvm/MC/MCMachObjectWriter.h"
15#include "llvm/MC/MCObjectWriter.h"
16#include "llvm/MC/MCSPIRVObjectWriter.h"
17#include "llvm/MC/MCWasmObjectWriter.h"
18#include "llvm/MC/MCWinCOFFObjectWriter.h"
19#include "llvm/MC/MCXCOFFObjectWriter.h"
20#include <cassert>
21#include <cstddef>
22#include <cstdint>
23
24using namespace llvm;
25
26MCAsmBackend::MCAsmBackend(llvm::endianness Endian, unsigned RelaxFixupKind)
27 : Endian(Endian), RelaxFixupKind(RelaxFixupKind) {}
28
29MCAsmBackend::~MCAsmBackend() = default;
30
31std::unique_ptr<MCObjectWriter>
32MCAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
33 auto TW = createObjectTargetWriter();
34 switch (TW->getFormat()) {
35 case Triple::ELF:
36 return createELFObjectWriter(MOTW: cast<MCELFObjectTargetWriter>(Val: std::move(TW)),
37 OS, IsLittleEndian: Endian == llvm::endianness::little);
38 case Triple::MachO:
39 return createMachObjectWriter(MOTW: cast<MCMachObjectTargetWriter>(Val: std::move(TW)),
40 OS, IsLittleEndian: Endian == llvm::endianness::little);
41 case Triple::COFF:
42 return createWinCOFFObjectWriter(
43 MOTW: cast<MCWinCOFFObjectTargetWriter>(Val: std::move(TW)), OS);
44 case Triple::SPIRV:
45 return createSPIRVObjectWriter(
46 MOTW: cast<MCSPIRVObjectTargetWriter>(Val: std::move(TW)), OS);
47 case Triple::Wasm:
48 return createWasmObjectWriter(MOTW: cast<MCWasmObjectTargetWriter>(Val: std::move(TW)),
49 OS);
50 case Triple::GOFF:
51 return createGOFFObjectWriter(MOTW: cast<MCGOFFObjectTargetWriter>(Val: std::move(TW)),
52 OS);
53 case Triple::XCOFF:
54 return createXCOFFObjectWriter(
55 MOTW: cast<MCXCOFFObjectTargetWriter>(Val: std::move(TW)), OS);
56 case Triple::DXContainer:
57 return createDXContainerObjectWriter(
58 MOTW: cast<MCDXContainerTargetWriter>(Val: std::move(TW)), OS);
59 default:
60 llvm_unreachable("unexpected object format");
61 }
62}
63
64std::unique_ptr<MCObjectWriter>
65MCAsmBackend::createDwoObjectWriter(raw_pwrite_stream &OS,
66 raw_pwrite_stream &DwoOS) const {
67 auto TW = createObjectTargetWriter();
68 switch (TW->getFormat()) {
69 case Triple::COFF:
70 return createWinCOFFDwoObjectWriter(
71 MOTW: cast<MCWinCOFFObjectTargetWriter>(Val: std::move(TW)), OS, DwoOS);
72 case Triple::ELF:
73 return createELFDwoObjectWriter(
74 MOTW: cast<MCELFObjectTargetWriter>(Val: std::move(TW)), OS, DwoOS,
75 IsLittleEndian: Endian == llvm::endianness::little);
76 case Triple::Wasm:
77 return createWasmDwoObjectWriter(
78 MOTW: cast<MCWasmObjectTargetWriter>(Val: std::move(TW)), OS, DwoOS);
79 default:
80 report_fatal_error(reason: "dwo only supported with COFF, ELF, and Wasm");
81 }
82}
83
84std::optional<MCFixupKind> MCAsmBackend::getFixupKind(StringRef Name) const {
85 return std::nullopt;
86}
87
88const MCFixupKindInfo &MCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
89 static const MCFixupKindInfo Builtins[] = {
90 {.Name: "FK_NONE", .TargetOffset: 0, .TargetSize: 0, .Flags: 0},
91 {.Name: "FK_Data_1", .TargetOffset: 0, .TargetSize: 8, .Flags: 0},
92 {.Name: "FK_Data_2", .TargetOffset: 0, .TargetSize: 16, .Flags: 0},
93 {.Name: "FK_Data_4", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
94 {.Name: "FK_Data_8", .TargetOffset: 0, .TargetSize: 64, .Flags: 0},
95 {.Name: "FK_Data_leb128", .TargetOffset: 0, .TargetSize: 0, .Flags: 0},
96 {.Name: "FK_PCRel_1", .TargetOffset: 0, .TargetSize: 8, .Flags: MCFixupKindInfo::FKF_IsPCRel},
97 {.Name: "FK_PCRel_2", .TargetOffset: 0, .TargetSize: 16, .Flags: MCFixupKindInfo::FKF_IsPCRel},
98 {.Name: "FK_PCRel_4", .TargetOffset: 0, .TargetSize: 32, .Flags: MCFixupKindInfo::FKF_IsPCRel},
99 {.Name: "FK_PCRel_8", .TargetOffset: 0, .TargetSize: 64, .Flags: MCFixupKindInfo::FKF_IsPCRel},
100 {.Name: "FK_GPRel_1", .TargetOffset: 0, .TargetSize: 8, .Flags: 0},
101 {.Name: "FK_GPRel_2", .TargetOffset: 0, .TargetSize: 16, .Flags: 0},
102 {.Name: "FK_GPRel_4", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
103 {.Name: "FK_GPRel_8", .TargetOffset: 0, .TargetSize: 64, .Flags: 0},
104 {.Name: "FK_DTPRel_4", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
105 {.Name: "FK_DTPRel_8", .TargetOffset: 0, .TargetSize: 64, .Flags: 0},
106 {.Name: "FK_TPRel_4", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
107 {.Name: "FK_TPRel_8", .TargetOffset: 0, .TargetSize: 64, .Flags: 0},
108 {.Name: "FK_SecRel_1", .TargetOffset: 0, .TargetSize: 8, .Flags: 0},
109 {.Name: "FK_SecRel_2", .TargetOffset: 0, .TargetSize: 16, .Flags: 0},
110 {.Name: "FK_SecRel_4", .TargetOffset: 0, .TargetSize: 32, .Flags: 0},
111 {.Name: "FK_SecRel_8", .TargetOffset: 0, .TargetSize: 64, .Flags: 0},
112 };
113
114 assert((size_t)Kind <= std::size(Builtins) && "Unknown fixup kind");
115 return Builtins[Kind];
116}
117
118bool MCAsmBackend::fixupNeedsRelaxationAdvanced(
119 const MCFixup &Fixup, bool Resolved, uint64_t Value,
120 const MCRelaxableFragment *DF, const MCAsmLayout &Layout,
121 const bool WasForced) const {
122 if (!Resolved)
123 return true;
124 return fixupNeedsRelaxation(Fixup, Value, DF, Layout);
125}
126
127bool MCAsmBackend::isDarwinCanonicalPersonality(const MCSymbol *Sym) const {
128 // Consider a NULL personality (ie., no personality encoding) to be canonical
129 // because it's always at 0.
130 if (!Sym)
131 return true;
132
133 if (!Sym->isMachO())
134 llvm_unreachable("Expected MachO symbols only");
135
136 StringRef name = Sym->getName();
137 // XXX: We intentionally leave out "___gcc_personality_v0" because, despite
138 // being system-defined like these two, it is not very commonly-used.
139 // Reserving an empty slot for it seems silly.
140 return name == "___gxx_personality_v0" || name == "___objc_personality_v0";
141}
142

source code of llvm/lib/MC/MCAsmBackend.cpp