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//===- Disassembler.cpp - Disassembler for hex strings --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This class implements the disassembler of strings of bytes written in
// hexadecimal, from standard input or from a file.
//
//===----------------------------------------------------------------------===//
#include "Disassembler.h"
#include "llvm/ADT/Triple.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDisassembler/MCDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
typedef std::pair<std::vector<unsigned char>, std::vector<const char *>>
ByteArrayTy;
static bool PrintInsts(const MCDisassembler &DisAsm,
const ByteArrayTy &Bytes,
SourceMgr &SM, raw_ostream &Out,
MCStreamer &Streamer, bool InAtomicBlock,
const MCSubtargetInfo &STI) {
ArrayRef<uint8_t> Data(Bytes.first.data(), Bytes.first.size());
// Disassemble it to strings.
uint64_t Size;
uint64_t Index;
for (Index = 0; Index < Bytes.first.size(); Index += Size) {
MCInst Inst;
MCDisassembler::DecodeStatus S;
S = DisAsm.getInstruction(Inst, Size, Data.slice(Index), Index, nulls());
switch (S) {
case MCDisassembler::Fail:
SM.PrintMessage(SMLoc::getFromPointer(Bytes.second[Index]),
SourceMgr::DK_Warning,
"invalid instruction encoding");
// Don't try to resynchronise the stream in a block
if (InAtomicBlock)
return true;
if (Size == 0)
Size = 1; // skip illegible bytes
break;
case MCDisassembler::SoftFail:
SM.PrintMessage(SMLoc::getFromPointer(Bytes.second[Index]),
SourceMgr::DK_Warning,
"potentially undefined instruction encoding");
[[fallthrough]];
case MCDisassembler::Success:
Streamer.emitInstruction(Inst, STI);
break;
}
}
return false;
}
static bool SkipToToken(StringRef &Str) {
for (;;) {
if (Str.empty())
return false;
// Strip horizontal whitespace and commas.
if (size_t Pos = Str.find_first_not_of(" \t\r\n,")) {
Str = Str.substr(Pos);
continue;
}
// If this is the start of a comment, remove the rest of the line.
if (Str[0] == '#') {
Str = Str.substr(Str.find_first_of('\n'));
continue;
}
return true;
}
}
static bool ByteArrayFromString(ByteArrayTy &ByteArray,
StringRef &Str,
SourceMgr &SM) {
while (SkipToToken(Str)) {
// Handled by higher level
if (Str[0] == '[' || Str[0] == ']')
return false;
// Get the current token.
size_t Next = Str.find_first_of(" \t\n\r,#[]");
StringRef Value = Str.substr(0, Next);
// Convert to a byte and add to the byte vector.
unsigned ByteVal;
if (Value.getAsInteger(0, ByteVal) || ByteVal > 255) {
// If we have an error, print it and skip to the end of line.
SM.PrintMessage(SMLoc::getFromPointer(Value.data()), SourceMgr::DK_Error,
"invalid input token");
Str = Str.substr(Str.find('\n'));
ByteArray.first.clear();
ByteArray.second.clear();
continue;
}
ByteArray.first.push_back(ByteVal);
ByteArray.second.push_back(Value.data());
Str = Str.substr(Next);
}
return false;
}
int Disassembler::disassemble(const Target &T, const std::string &Triple,
MCSubtargetInfo &STI, MCStreamer &Streamer,
MemoryBuffer &Buffer, SourceMgr &SM,
MCContext &Ctx, raw_ostream &Out,
const MCTargetOptions &MCOptions) {
std::unique_ptr<const MCRegisterInfo> MRI(T.createMCRegInfo(Triple));
if (!MRI) {
errs() << "error: no register info for target " << Triple << "\n";
return -1;
}
std::unique_ptr<const MCAsmInfo> MAI(
T.createMCAsmInfo(*MRI, Triple, MCOptions));
if (!MAI) {
errs() << "error: no assembly info for target " << Triple << "\n";
return -1;
}
std::unique_ptr<const MCDisassembler> DisAsm(
T.createMCDisassembler(STI, Ctx));
if (!DisAsm) {
errs() << "error: no disassembler for target " << Triple << "\n";
return -1;
}
// Set up initial section manually here
Streamer.initSections(false, STI);
bool ErrorOccurred = false;
// Convert the input to a vector for disassembly.
ByteArrayTy ByteArray;
StringRef Str = Buffer.getBuffer();
bool InAtomicBlock = false;
while (SkipToToken(Str)) {
ByteArray.first.clear();
ByteArray.second.clear();
if (Str[0] == '[') {
if (InAtomicBlock) {
SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error,
"nested atomic blocks make no sense");
ErrorOccurred = true;
}
InAtomicBlock = true;
Str = Str.drop_front();
continue;
} else if (Str[0] == ']') {
if (!InAtomicBlock) {
SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error,
"attempt to close atomic block without opening");
ErrorOccurred = true;
}
InAtomicBlock = false;
Str = Str.drop_front();
continue;
}
// It's a real token, get the bytes and emit them
ErrorOccurred |= ByteArrayFromString(ByteArray, Str, SM);
if (!ByteArray.first.empty())
ErrorOccurred |= PrintInsts(*DisAsm, ByteArray, SM, Out, Streamer,
InAtomicBlock, STI);
}
if (InAtomicBlock) {
SM.PrintMessage(SMLoc::getFromPointer(Str.data()), SourceMgr::DK_Error,
"unclosed atomic block");
ErrorOccurred = true;
}
return ErrorOccurred;
}
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