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 25 MCAsmBackend::MCAsmBackend(support::endianness Endian) : Endian(Endian) {} 26 27 MCAsmBackend::~MCAsmBackend() = default; 28 29 std::unique_ptr<MCObjectWriter> 30 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> 54 MCAsmBackend::createDwoObjectWriter(raw_pwrite_stream &OS, 55 raw_pwrite_stream &DwoOS) const { 56 auto TW = createObjectTargetWriter(); 57 switch (TW->getFormat()) { 58 case Triple::ELF: 59 return createELFDwoObjectWriter( 60 cast<MCELFObjectTargetWriter>(std::move(TW)), OS, DwoOS, 61 Endian == support::little); 62 case Triple::Wasm: 63 return createWasmDwoObjectWriter( 64 cast<MCWasmObjectTargetWriter>(std::move(TW)), OS, DwoOS); 65 default: 66 report_fatal_error("dwo only supported with ELF and Wasm"); 67 } 68 } 69 70 Optional<MCFixupKind> MCAsmBackend::getFixupKind(StringRef Name) const { 71 return None; 72 } 73 74 const MCFixupKindInfo &MCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { 75 static const MCFixupKindInfo Builtins[] = { 76 {"FK_NONE", 0, 0, 0}, 77 {"FK_Data_1", 0, 8, 0}, 78 {"FK_Data_2", 0, 16, 0}, 79 {"FK_Data_4", 0, 32, 0}, 80 {"FK_Data_8", 0, 64, 0}, 81 {"FK_Data_6b", 0, 6, 0}, 82 {"FK_PCRel_1", 0, 8, MCFixupKindInfo::FKF_IsPCRel}, 83 {"FK_PCRel_2", 0, 16, MCFixupKindInfo::FKF_IsPCRel}, 84 {"FK_PCRel_4", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, 85 {"FK_PCRel_8", 0, 64, MCFixupKindInfo::FKF_IsPCRel}, 86 {"FK_GPRel_1", 0, 8, 0}, 87 {"FK_GPRel_2", 0, 16, 0}, 88 {"FK_GPRel_4", 0, 32, 0}, 89 {"FK_GPRel_8", 0, 64, 0}, 90 {"FK_DTPRel_4", 0, 32, 0}, 91 {"FK_DTPRel_8", 0, 64, 0}, 92 {"FK_TPRel_4", 0, 32, 0}, 93 {"FK_TPRel_8", 0, 64, 0}, 94 {"FK_SecRel_1", 0, 8, 0}, 95 {"FK_SecRel_2", 0, 16, 0}, 96 {"FK_SecRel_4", 0, 32, 0}, 97 {"FK_SecRel_8", 0, 64, 0}, 98 }; 99 100 assert((size_t)Kind <= array_lengthof(Builtins) && "Unknown fixup kind"); 101 return Builtins[Kind]; 102 } 103 104 bool MCAsmBackend::fixupNeedsRelaxationAdvanced( 105 const MCFixup &Fixup, bool Resolved, uint64_t Value, 106 const MCRelaxableFragment *DF, const MCAsmLayout &Layout, 107 const bool WasForced) const { 108 if (!Resolved) 109 return true; 110 return fixupNeedsRelaxation(Fixup, Value, DF, Layout); 111 } 112