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/MCCodePadder.h" 13 #include "llvm/MC/MCELFObjectWriter.h" 14 #include "llvm/MC/MCFixupKindInfo.h" 15 #include "llvm/MC/MCMachObjectWriter.h" 16 #include "llvm/MC/MCObjectWriter.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 24 using namespace llvm; 25 26 MCAsmBackend::MCAsmBackend(support::endianness Endian) 27 : CodePadder(new MCCodePadder()), Endian(Endian) {} 28 29 MCAsmBackend::~MCAsmBackend() = default; 30 31 std::unique_ptr<MCObjectWriter> 32 MCAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const { 33 auto TW = createObjectTargetWriter(); 34 switch (TW->getFormat()) { 35 case Triple::ELF: 36 return createELFObjectWriter(cast<MCELFObjectTargetWriter>(std::move(TW)), OS, 37 Endian == support::little); 38 case Triple::MachO: 39 return createMachObjectWriter(cast<MCMachObjectTargetWriter>(std::move(TW)), 40 OS, Endian == support::little); 41 case Triple::COFF: 42 return createWinCOFFObjectWriter( 43 cast<MCWinCOFFObjectTargetWriter>(std::move(TW)), OS); 44 case Triple::Wasm: 45 return createWasmObjectWriter(cast<MCWasmObjectTargetWriter>(std::move(TW)), 46 OS); 47 case Triple::XCOFF: 48 return createXCOFFObjectWriter( 49 cast<MCXCOFFObjectTargetWriter>(std::move(TW)), OS); 50 default: 51 llvm_unreachable("unexpected object format"); 52 } 53 } 54 55 std::unique_ptr<MCObjectWriter> 56 MCAsmBackend::createDwoObjectWriter(raw_pwrite_stream &OS, 57 raw_pwrite_stream &DwoOS) const { 58 auto TW = createObjectTargetWriter(); 59 if (TW->getFormat() != Triple::ELF) 60 report_fatal_error("dwo only supported with ELF"); 61 return createELFDwoObjectWriter(cast<MCELFObjectTargetWriter>(std::move(TW)), 62 OS, DwoOS, Endian == support::little); 63 } 64 65 Optional<MCFixupKind> MCAsmBackend::getFixupKind(StringRef Name) const { 66 return None; 67 } 68 69 const MCFixupKindInfo &MCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { 70 static const MCFixupKindInfo Builtins[] = { 71 {"FK_NONE", 0, 0, 0}, 72 {"FK_Data_1", 0, 8, 0}, 73 {"FK_Data_2", 0, 16, 0}, 74 {"FK_Data_4", 0, 32, 0}, 75 {"FK_Data_8", 0, 64, 0}, 76 {"FK_Data_6b", 0, 6, 0}, 77 {"FK_PCRel_1", 0, 8, MCFixupKindInfo::FKF_IsPCRel}, 78 {"FK_PCRel_2", 0, 16, MCFixupKindInfo::FKF_IsPCRel}, 79 {"FK_PCRel_4", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, 80 {"FK_PCRel_8", 0, 64, MCFixupKindInfo::FKF_IsPCRel}, 81 {"FK_GPRel_1", 0, 8, 0}, 82 {"FK_GPRel_2", 0, 16, 0}, 83 {"FK_GPRel_4", 0, 32, 0}, 84 {"FK_GPRel_8", 0, 64, 0}, 85 {"FK_DTPRel_4", 0, 32, 0}, 86 {"FK_DTPRel_8", 0, 64, 0}, 87 {"FK_TPRel_4", 0, 32, 0}, 88 {"FK_TPRel_8", 0, 64, 0}, 89 {"FK_SecRel_1", 0, 8, 0}, 90 {"FK_SecRel_2", 0, 16, 0}, 91 {"FK_SecRel_4", 0, 32, 0}, 92 {"FK_SecRel_8", 0, 64, 0}, 93 {"FK_Data_Add_1", 0, 8, 0}, 94 {"FK_Data_Add_2", 0, 16, 0}, 95 {"FK_Data_Add_4", 0, 32, 0}, 96 {"FK_Data_Add_8", 0, 64, 0}, 97 {"FK_Data_Add_6b", 0, 6, 0}, 98 {"FK_Data_Sub_1", 0, 8, 0}, 99 {"FK_Data_Sub_2", 0, 16, 0}, 100 {"FK_Data_Sub_4", 0, 32, 0}, 101 {"FK_Data_Sub_8", 0, 64, 0}, 102 {"FK_Data_Sub_6b", 0, 6, 0}}; 103 104 assert((size_t)Kind <= array_lengthof(Builtins) && "Unknown fixup kind"); 105 return Builtins[Kind]; 106 } 107 108 bool MCAsmBackend::fixupNeedsRelaxationAdvanced( 109 const MCFixup &Fixup, bool Resolved, uint64_t Value, 110 const MCRelaxableFragment *DF, const MCAsmLayout &Layout, 111 const bool WasForced) const { 112 if (!Resolved) 113 return true; 114 return fixupNeedsRelaxation(Fixup, Value, DF, Layout); 115 } 116 117 void MCAsmBackend::handleCodePaddingBasicBlockStart( 118 MCObjectStreamer *OS, const MCCodePaddingContext &Context) { 119 CodePadder->handleBasicBlockStart(OS, Context); 120 } 121 122 void MCAsmBackend::handleCodePaddingBasicBlockEnd( 123 const MCCodePaddingContext &Context) { 124 CodePadder->handleBasicBlockEnd(Context); 125 } 126 127 void MCAsmBackend::handleCodePaddingInstructionBegin(const MCInst &Inst) { 128 CodePadder->handleInstructionBegin(Inst); 129 } 130 131 void MCAsmBackend::handleCodePaddingInstructionEnd(const MCInst &Inst) { 132 CodePadder->handleInstructionEnd(Inst); 133 } 134 135 bool MCAsmBackend::relaxFragment(MCPaddingFragment *PF, MCAsmLayout &Layout) { 136 return CodePadder->relaxFragment(PF, Layout); 137 } 138