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/MC/MCAsmInfo.h" 16 #include "llvm/MC/MCContext.h" 17 #include "llvm/MC/MCDisassembler/MCDisassembler.h" 18 #include "llvm/MC/MCInst.h" 19 #include "llvm/MC/MCObjectFileInfo.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 #include "llvm/TargetParser/Triple.h" 28 29 using namespace llvm; 30 31 typedef std::pair<std::vector<unsigned char>, std::vector<const char *>> 32 ByteArrayTy; 33 34 static bool PrintInsts(const MCDisassembler &DisAsm, const ByteArrayTy &Bytes, 35 SourceMgr &SM, MCStreamer &Streamer, bool InAtomicBlock, 36 const MCSubtargetInfo &STI) { 37 ArrayRef<uint8_t> Data(Bytes.first.data(), Bytes.first.size()); 38 39 // Disassemble it to strings. 40 uint64_t Size; 41 uint64_t Index; 42 43 for (Index = 0; Index < Bytes.first.size(); Index += Size) { 44 MCInst Inst; 45 46 MCDisassembler::DecodeStatus S; 47 S = DisAsm.getInstruction(Inst, Size, Data.slice(Index), Index, nulls()); 48 switch (S) { 49 case MCDisassembler::Fail: 50 SM.PrintMessage(SMLoc::getFromPointer(Bytes.second[Index]), 51 SourceMgr::DK_Warning, 52 "invalid instruction encoding"); 53 // Don't try to resynchronise the stream in a block 54 if (InAtomicBlock) 55 return true; 56 57 if (Size == 0) 58 Size = 1; // skip illegible bytes 59 60 break; 61 62 case MCDisassembler::SoftFail: 63 SM.PrintMessage(SMLoc::getFromPointer(Bytes.second[Index]), 64 SourceMgr::DK_Warning, 65 "potentially undefined instruction encoding"); 66 [[fallthrough]]; 67 68 case MCDisassembler::Success: 69 Streamer.emitInstruction(Inst, STI); 70 break; 71 } 72 } 73 74 return false; 75 } 76 77 static bool SkipToToken(StringRef &Str) { 78 for (;;) { 79 if (Str.empty()) 80 return false; 81 82 // Strip horizontal whitespace and commas. 83 if (size_t Pos = Str.find_first_not_of(" \t\r\n,")) { 84 Str = Str.substr(Pos); 85 continue; 86 } 87 88 // If this is the start of a comment, remove the rest of the line. 89 if (Str[0] == '#') { 90 Str = Str.substr(Str.find_first_of('\n')); 91 continue; 92 } 93 return true; 94 } 95 } 96 97 98 static bool ByteArrayFromString(ByteArrayTy &ByteArray, 99 StringRef &Str, 100 SourceMgr &SM) { 101 while (SkipToToken(Str)) { 102 // Handled by higher level 103 if (Str[0] == '[' || Str[0] == ']') 104 return false; 105 106 // Get the current token. 107 size_t Next = Str.find_first_of(" \t\n\r,#[]"); 108 StringRef Value = Str.substr(0, Next); 109 110 // Convert to a byte and add to the byte vector. 111 unsigned ByteVal; 112 if (Value.getAsInteger(0, ByteVal) || ByteVal > 255) { 113 // If we have an error, print it and skip to the end of line. 114 SM.PrintMessage(SMLoc::getFromPointer(Value.data()), SourceMgr::DK_Error, 115 "invalid input token"); 116 Str = Str.substr(Str.find('\n')); 117 ByteArray.first.clear(); 118 ByteArray.second.clear(); 119 continue; 120 } 121 122 ByteArray.first.push_back(ByteVal); 123 ByteArray.second.push_back(Value.data()); 124 Str = Str.substr(Next); 125 } 126 127 return false; 128 } 129 130 int Disassembler::disassemble(const Target &T, const std::string &Triple, 131 MCSubtargetInfo &STI, MCStreamer &Streamer, 132 MemoryBuffer &Buffer, SourceMgr &SM, 133 MCContext &Ctx, 134 const MCTargetOptions &MCOptions) { 135 136 std::unique_ptr<const MCRegisterInfo> MRI(T.createMCRegInfo(Triple)); 137 if (!MRI) { 138 errs() << "error: no register info for target " << Triple << "\n"; 139 return -1; 140 } 141 142 std::unique_ptr<const MCAsmInfo> MAI( 143 T.createMCAsmInfo(*MRI, Triple, MCOptions)); 144 if (!MAI) { 145 errs() << "error: no assembly info for target " << Triple << "\n"; 146 return -1; 147 } 148 149 std::unique_ptr<const MCDisassembler> DisAsm( 150 T.createMCDisassembler(STI, Ctx)); 151 if (!DisAsm) { 152 errs() << "error: no disassembler for target " << Triple << "\n"; 153 return -1; 154 } 155 156 // Set up initial section manually here 157 Streamer.initSections(false, STI); 158 159 bool ErrorOccurred = false; 160 161 // Convert the input to a vector for disassembly. 162 ByteArrayTy ByteArray; 163 StringRef Str = Buffer.getBuffer(); 164 bool InAtomicBlock = false; 165 166 while (SkipToToken(Str)) { 167 ByteArray.first.clear(); 168 ByteArray.second.clear(); 169 170 if (Str[0] == '[') { 171 if (InAtomicBlock) { 172 SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error, 173 "nested atomic blocks make no sense"); 174 ErrorOccurred = true; 175 } 176 InAtomicBlock = true; 177 Str = Str.drop_front(); 178 continue; 179 } else if (Str[0] == ']') { 180 if (!InAtomicBlock) { 181 SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error, 182 "attempt to close atomic block without opening"); 183 ErrorOccurred = true; 184 } 185 InAtomicBlock = false; 186 Str = Str.drop_front(); 187 continue; 188 } 189 190 // It's a real token, get the bytes and emit them 191 ErrorOccurred |= ByteArrayFromString(ByteArray, Str, SM); 192 193 if (!ByteArray.first.empty()) 194 ErrorOccurred |= 195 PrintInsts(*DisAsm, ByteArray, SM, Streamer, InAtomicBlock, STI); 196 } 197 198 if (InAtomicBlock) { 199 SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error, 200 "unclosed atomic block"); 201 ErrorOccurred = true; 202 } 203 204 return ErrorOccurred; 205 } 206