1//===- Disassembler.cpp - Disassembler for hex strings --------------------===// 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// This class implements the disassembler of strings of bytes written in 10// hexadecimal, from standard input or from a file. 11// 12//===----------------------------------------------------------------------===// 13 14#include "Disassembler.h" 15#include "llvm/ADT/Triple.h" 16#include "llvm/MC/MCAsmInfo.h" 17#include "llvm/MC/MCContext.h" 18#include "llvm/MC/MCDisassembler/MCDisassembler.h" 19#include "llvm/MC/MCInst.h" 20#include "llvm/MC/MCRegisterInfo.h" 21#include "llvm/MC/MCStreamer.h" 22#include "llvm/MC/MCSubtargetInfo.h" 23#include "llvm/MC/TargetRegistry.h" 24#include "llvm/Support/MemoryBuffer.h" 25#include "llvm/Support/SourceMgr.h" 26#include "llvm/Support/raw_ostream.h" 27 28using namespace llvm; 29 30typedef std::pair<std::vector<unsigned char>, std::vector<const char *>> 31 ByteArrayTy; 32 33static bool PrintInsts(const MCDisassembler &DisAsm, const ByteArrayTy &Bytes, 34 SourceMgr &SM, raw_ostream &Out, MCStreamer &Streamer, 35 bool InAtomicBlock, const MCSubtargetInfo &STI) { 36 ArrayRef<uint8_t> Data(Bytes.first.data(), Bytes.first.size()); 37 38 // Disassemble it to strings. 39 uint64_t Size; 40 uint64_t Index; 41 42 for (Index = 0; Index < Bytes.first.size(); Index += Size) { 43 MCInst Inst; 44 45 MCDisassembler::DecodeStatus S; 46 S = DisAsm.getInstruction(Inst, Size, Data.slice(Index), Index, nulls()); 47 switch (S) { 48 case MCDisassembler::Fail: 49 SM.PrintMessage(SMLoc::getFromPointer(Bytes.second[Index]), 50 SourceMgr::DK_Warning, "invalid instruction encoding"); 51 // Don't try to resynchronise the stream in a block 52 if (InAtomicBlock) 53 return true; 54 55 if (Size == 0) 56 Size = 1; // skip illegible bytes 57 58 break; 59 60 case MCDisassembler::SoftFail: 61 SM.PrintMessage(SMLoc::getFromPointer(Bytes.second[Index]), 62 SourceMgr::DK_Warning, 63 "potentially undefined instruction encoding"); 64 [[fallthrough]]; 65 66 case MCDisassembler::Success: 67 Streamer.emitInstruction(Inst, STI); 68 break; 69 } 70 } 71 72 return false; 73} 74 75static bool SkipToToken(StringRef &Str) { 76 for (;;) { 77 if (Str.empty()) 78 return false; 79 80 // Strip horizontal whitespace and commas. 81 if (size_t Pos = Str.find_first_not_of(" \t\r\n,")) { 82 Str = Str.substr(Pos); 83 continue; 84 } 85 86 // If this is the start of a comment, remove the rest of the line. 87 if (Str[0] == '#') { 88 Str = Str.substr(Str.find_first_of('\n')); 89 continue; 90 } 91 return true; 92 } 93} 94 95static bool ByteArrayFromString(ByteArrayTy &ByteArray, StringRef &Str, 96 SourceMgr &SM) { 97 while (SkipToToken(Str)) { 98 // Handled by higher level 99 if (Str[0] == '[' || Str[0] == ']') 100 return false; 101 102 // Get the current token. 103 size_t Next = Str.find_first_of(" \t\n\r,#[]"); 104 StringRef Value = Str.substr(0, Next); 105 106 // Convert to a byte and add to the byte vector. 107 unsigned ByteVal; 108 if (Value.getAsInteger(0, ByteVal) || ByteVal > 255) { 109 // If we have an error, print it and skip to the end of line. 110 SM.PrintMessage(SMLoc::getFromPointer(Value.data()), SourceMgr::DK_Error, 111 "invalid input token"); 112 Str = Str.substr(Str.find('\n')); 113 ByteArray.first.clear(); 114 ByteArray.second.clear(); 115 continue; 116 } 117 118 ByteArray.first.push_back(ByteVal); 119 ByteArray.second.push_back(Value.data()); 120 Str = Str.substr(Next); 121 } 122 123 return false; 124} 125 126int Disassembler::disassemble(const Target &T, const std::string &TripleName, 127 MCSubtargetInfo &STI, MCStreamer &Streamer, 128 MemoryBuffer &Buffer, SourceMgr &SM, 129 raw_ostream &Out) { 130 std::unique_ptr<const MCRegisterInfo> MRI(T.createMCRegInfo(TripleName)); 131 if (!MRI) { 132 errs() << "error: no register info for target " << TripleName << "\n"; 133 return -1; 134 } 135 136 MCTargetOptions MCOptions; 137 std::unique_ptr<const MCAsmInfo> MAI( 138 T.createMCAsmInfo(*MRI, TripleName, MCOptions)); 139 if (!MAI) { 140 errs() << "error: no assembly info for target " << TripleName << "\n"; 141 return -1; 142 } 143 144 // Set up the MCContext for creating symbols and MCExpr's. 145 MCContext Ctx(Triple(TripleName), MAI.get(), MRI.get(), &STI); 146 147 std::unique_ptr<const MCDisassembler> DisAsm( 148 T.createMCDisassembler(STI, Ctx)); 149 if (!DisAsm) { 150 errs() << "error: no disassembler for target " << TripleName << "\n"; 151 return -1; 152 } 153 154 // Set up initial section manually here 155 Streamer.initSections(false, STI); 156 157 bool ErrorOccurred = false; 158 159 // Convert the input to a vector for disassembly. 160 ByteArrayTy ByteArray; 161 StringRef Str = Buffer.getBuffer(); 162 bool InAtomicBlock = false; 163 164 while (SkipToToken(Str)) { 165 ByteArray.first.clear(); 166 ByteArray.second.clear(); 167 168 if (Str[0] == '[') { 169 if (InAtomicBlock) { 170 SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error, 171 "nested atomic blocks make no sense"); 172 ErrorOccurred = true; 173 } 174 InAtomicBlock = true; 175 Str = Str.drop_front(); 176 continue; 177 } else if (Str[0] == ']') { 178 if (!InAtomicBlock) { 179 SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error, 180 "attempt to close atomic block without opening"); 181 ErrorOccurred = true; 182 } 183 InAtomicBlock = false; 184 Str = Str.drop_front(); 185 continue; 186 } 187 188 // It's a real token, get the bytes and emit them 189 ErrorOccurred |= ByteArrayFromString(ByteArray, Str, SM); 190 191 if (!ByteArray.first.empty()) 192 ErrorOccurred |= 193 PrintInsts(*DisAsm, ByteArray, SM, Out, Streamer, InAtomicBlock, STI); 194 } 195 196 if (InAtomicBlock) { 197 SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error, 198 "unclosed atomic block"); 199 ErrorOccurred = true; 200 } 201 202 return ErrorOccurred; 203} 204