tools/llvm-mc/Disassembler.cpp

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