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//===-- llvm-mc.cpp - Machine Code Hacking Driver ---------------*- C++ -*-===//
//
// 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 utility is a simple driver that allows command line hacking on machine
// code.
//
//===----------------------------------------------------------------------===//
#include "Disassembler.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCParser/AsmLexer.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetOptionsCommandFlags.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/WithColor.h"
using namespace llvm;
static mc::RegisterMCTargetOptionsFlags MOF;
static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
static cl::opt<std::string> OutputFilename("o", cl::desc("Output filename"),
cl::value_desc("filename"),
cl::init("-"));
static cl::opt<std::string> SplitDwarfFile("split-dwarf-file",
cl::desc("DWO output filename"),
cl::value_desc("filename"));
static cl::opt<bool>
ShowEncoding("show-encoding", cl::desc("Show instruction encodings"));
static cl::opt<bool> RelaxELFRel(
"relax-relocations", cl::init(true),
cl::desc("Emit R_X86_64_GOTPCRELX instead of R_X86_64_GOTPCREL"));
static cl::opt<DebugCompressionType> CompressDebugSections(
"compress-debug-sections", cl::ValueOptional,
cl::init(DebugCompressionType::None),
cl::desc("Choose DWARF debug sections compression:"),
cl::values(clEnumValN(DebugCompressionType::None, "none", "No compression"),
clEnumValN(DebugCompressionType::Z, "zlib",
"Use zlib compression"),
clEnumValN(DebugCompressionType::GNU, "zlib-gnu",
"Use zlib-gnu compression (deprecated)")));
static cl::opt<bool>
ShowInst("show-inst", cl::desc("Show internal instruction representation"));
static cl::opt<bool>
ShowInstOperands("show-inst-operands",
cl::desc("Show instructions operands as parsed"));
static cl::opt<unsigned>
OutputAsmVariant("output-asm-variant",
cl::desc("Syntax variant to use for output printing"));
static cl::opt<bool>
PrintImmHex("print-imm-hex", cl::init(false),
cl::desc("Prefer hex format for immediate values"));
static cl::list<std::string>
DefineSymbol("defsym", cl::desc("Defines a symbol to be an integer constant"));
static cl::opt<bool>
PreserveComments("preserve-comments",
cl::desc("Preserve Comments in outputted assembly"));
enum OutputFileType {
OFT_Null,
OFT_AssemblyFile,
OFT_ObjectFile
};
static cl::opt<OutputFileType>
FileType("filetype", cl::init(OFT_AssemblyFile),
cl::desc("Choose an output file type:"),
cl::values(
clEnumValN(OFT_AssemblyFile, "asm",
"Emit an assembly ('.s') file"),
clEnumValN(OFT_Null, "null",
"Don't emit anything (for timing purposes)"),
clEnumValN(OFT_ObjectFile, "obj",
"Emit a native object ('.o') file")));
static cl::list<std::string>
IncludeDirs("I", cl::desc("Directory of include files"),
cl::value_desc("directory"), cl::Prefix);
static cl::opt<std::string>
ArchName("arch", cl::desc("Target arch to assemble for, "
"see -version for available targets"));
static cl::opt<std::string>
TripleName("triple", cl::desc("Target triple to assemble for, "
"see -version for available targets"));
static cl::opt<std::string>
MCPU("mcpu",
cl::desc("Target a specific cpu type (-mcpu=help for details)"),
cl::value_desc("cpu-name"),
cl::init(""));
static cl::list<std::string>
MAttrs("mattr",
cl::CommaSeparated,
cl::desc("Target specific attributes (-mattr=help for details)"),
cl::value_desc("a1,+a2,-a3,..."));
static cl::opt<bool> PIC("position-independent",
cl::desc("Position independent"), cl::init(false));
static cl::opt<bool>
LargeCodeModel("large-code-model",
cl::desc("Create cfi directives that assume the code might "
"be more than 2gb away"));
static cl::opt<bool>
NoInitialTextSection("n", cl::desc("Don't assume assembly file starts "
"in the text section"));
static cl::opt<bool>
GenDwarfForAssembly("g", cl::desc("Generate dwarf debugging info for assembly "
"source files"));
static cl::opt<std::string>
DebugCompilationDir("fdebug-compilation-dir",
cl::desc("Specifies the debug info's compilation dir"));
static cl::list<std::string>
DebugPrefixMap("fdebug-prefix-map",
cl::desc("Map file source paths in debug info"),
cl::value_desc("= separated key-value pairs"));
static cl::opt<std::string>
MainFileName("main-file-name",
cl::desc("Specifies the name we should consider the input file"));
static cl::opt<bool> SaveTempLabels("save-temp-labels",
cl::desc("Don't discard temporary labels"));
static cl::opt<bool> LexMasmIntegers(
"masm-integers",
cl::desc("Enable binary and hex masm integers (0b110 and 0ABCh)"));
static cl::opt<bool> LexMasmHexFloats(
"masm-hexfloats",
cl::desc("Enable MASM-style hex float initializers (3F800000r)"));
static cl::opt<bool> NoExecStack("no-exec-stack",
cl::desc("File doesn't need an exec stack"));
enum ActionType {
AC_AsLex,
AC_Assemble,
AC_Disassemble,
AC_MDisassemble,
};
static cl::opt<ActionType>
Action(cl::desc("Action to perform:"),
cl::init(AC_Assemble),
cl::values(clEnumValN(AC_AsLex, "as-lex",
"Lex tokens from a .s file"),
clEnumValN(AC_Assemble, "assemble",
"Assemble a .s file (default)"),
clEnumValN(AC_Disassemble, "disassemble",
"Disassemble strings of hex bytes"),
clEnumValN(AC_MDisassemble, "mdis",
"Marked up disassembly of strings of hex bytes")));
static const Target *GetTarget(const char *ProgName) {
// Figure out the target triple.
if (TripleName.empty())
TripleName = sys::getDefaultTargetTriple();
Triple TheTriple(Triple::normalize(TripleName));
// Get the target specific parser.
std::string Error;
const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple,
Error);
if (!TheTarget) {
WithColor::error(errs(), ProgName) << Error;
return nullptr;
}
// Update the triple name and return the found target.
TripleName = TheTriple.getTriple();
return TheTarget;
}
static std::unique_ptr<ToolOutputFile> GetOutputStream(StringRef Path,
sys::fs::OpenFlags Flags) {
std::error_code EC;
auto Out = std::make_unique<ToolOutputFile>(Path, EC, Flags);
if (EC) {
WithColor::error() << EC.message() << '\n';
return nullptr;
}
return Out;
}
static std::string DwarfDebugFlags;
static void setDwarfDebugFlags(int argc, char **argv) {
if (!getenv("RC_DEBUG_OPTIONS"))
return;
for (int i = 0; i < argc; i++) {
DwarfDebugFlags += argv[i];
if (i + 1 < argc)
DwarfDebugFlags += " ";
}
}
static std::string DwarfDebugProducer;
static void setDwarfDebugProducer() {
if(!getenv("DEBUG_PRODUCER"))
return;
DwarfDebugProducer += getenv("DEBUG_PRODUCER");
}
static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI,
raw_ostream &OS) {
AsmLexer Lexer(MAI);
Lexer.setBuffer(SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer());
bool Error = false;
while (Lexer.Lex().isNot(AsmToken::Eof)) {
Lexer.getTok().dump(OS);
OS << "\n";
if (Lexer.getTok().getKind() == AsmToken::Error)
Error = true;
}
return Error;
}
static int fillCommandLineSymbols(MCAsmParser &Parser) {
for (auto &I: DefineSymbol) {
auto Pair = StringRef(I).split('=');
auto Sym = Pair.first;
auto Val = Pair.second;
if (Sym.empty() || Val.empty()) {
WithColor::error() << "defsym must be of the form: sym=value: " << I
<< "\n";
return 1;
}
int64_t Value;
if (Val.getAsInteger(0, Value)) {
WithColor::error() << "value is not an integer: " << Val << "\n";
return 1;
}
Parser.getContext().setSymbolValue(Parser.getStreamer(), Sym, Value);
}
return 0;
}
static int AssembleInput(const char *ProgName, const Target *TheTarget,
SourceMgr &SrcMgr, MCContext &Ctx, MCStreamer &Str,
MCAsmInfo &MAI, MCSubtargetInfo &STI,
MCInstrInfo &MCII, MCTargetOptions const &MCOptions) {
std::unique_ptr<MCAsmParser> Parser(
createMCAsmParser(SrcMgr, Ctx, Str, MAI));
std::unique_ptr<MCTargetAsmParser> TAP(
TheTarget->createMCAsmParser(STI, *Parser, MCII, MCOptions));
if (!TAP) {
WithColor::error(errs(), ProgName)
<< "this target does not support assembly parsing.\n";
return 1;
}
int SymbolResult = fillCommandLineSymbols(*Parser);
if(SymbolResult)
return SymbolResult;
Parser->setShowParsedOperands(ShowInstOperands);
Parser->setTargetParser(*TAP);
Parser->getLexer().setLexMasmIntegers(LexMasmIntegers);
Parser->getLexer().setLexMasmHexFloats(LexMasmHexFloats);
int Res = Parser->Run(NoInitialTextSection);
return Res;
}
int main(int argc, char **argv) {
InitLLVM X(argc, argv);
// Initialize targets and assembly printers/parsers.
llvm::InitializeAllTargetInfos();
llvm::InitializeAllTargetMCs();
llvm::InitializeAllAsmParsers();
llvm::InitializeAllDisassemblers();
// Register the target printer for --version.
cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
cl::ParseCommandLineOptions(argc, argv, "llvm machine code playground\n");
const MCTargetOptions MCOptions = mc::InitMCTargetOptionsFromFlags();
setDwarfDebugFlags(argc, argv);
setDwarfDebugProducer();
const char *ProgName = argv[0];
const Target *TheTarget = GetTarget(ProgName);
if (!TheTarget)
return 1;
// Now that GetTarget() has (potentially) replaced TripleName, it's safe to
// construct the Triple object.
Triple TheTriple(TripleName);
ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
MemoryBuffer::getFileOrSTDIN(InputFilename);
if (std::error_code EC = BufferPtr.getError()) {
WithColor::error(errs(), ProgName)
<< InputFilename << ": " << EC.message() << '\n';
return 1;
}
MemoryBuffer *Buffer = BufferPtr->get();
SourceMgr SrcMgr;
// Tell SrcMgr about this buffer, which is what the parser will pick up.
SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
// Record the location of the include directories so that the lexer can find
// it later.
SrcMgr.setIncludeDirs(IncludeDirs);
std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
assert(MRI && "Unable to create target register info!");
std::unique_ptr<MCAsmInfo> MAI(
TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
assert(MAI && "Unable to create target asm info!");
MAI->setRelaxELFRelocations(RelaxELFRel);
if (CompressDebugSections != DebugCompressionType::None) {
if (!zlib::isAvailable()) {
WithColor::error(errs(), ProgName)
<< "build tools with zlib to enable -compress-debug-sections";
return 1;
}
MAI->setCompressDebugSections(CompressDebugSections);
}
MAI->setPreserveAsmComments(PreserveComments);
// FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
// MCObjectFileInfo needs a MCContext reference in order to initialize itself.
MCObjectFileInfo MOFI;
MCContext Ctx(MAI.get(), MRI.get(), &MOFI, &SrcMgr, &MCOptions);
MOFI.InitMCObjectFileInfo(TheTriple, PIC, Ctx, LargeCodeModel);
if (SaveTempLabels)
Ctx.setAllowTemporaryLabels(false);
Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
// Default to 4 for dwarf version.
unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4;
if (DwarfVersion < 2 || DwarfVersion > 5) {
errs() << ProgName << ": Dwarf version " << DwarfVersion
<< " is not supported." << '\n';
return 1;
}
Ctx.setDwarfVersion(DwarfVersion);
if (MCOptions.Dwarf64) {
// The 64-bit DWARF format was introduced in DWARFv3.
if (DwarfVersion < 3) {
errs() << ProgName
<< ": the 64-bit DWARF format is not supported for DWARF versions "
"prior to 3\n";
return 1;
}
// 32-bit targets don't support DWARF64, which requires 64-bit relocations.
if (MAI->getCodePointerSize() < 8) {
errs() << ProgName
<< ": the 64-bit DWARF format is only supported for 64-bit "
"targets\n";
return 1;
}
// If needsDwarfSectionOffsetDirective is true, we would eventually call
// MCStreamer::emitSymbolValue() with IsSectionRelative = true, but that
// is supported only for 4-byte long references.
if (MAI->needsDwarfSectionOffsetDirective()) {
errs() << ProgName << ": the 64-bit DWARF format is not supported for "
<< TheTriple.normalize() << "\n";
return 1;
}
Ctx.setDwarfFormat(dwarf::DWARF64);
}
if (!DwarfDebugFlags.empty())
Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
if (!DwarfDebugProducer.empty())
Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer));
if (!DebugCompilationDir.empty())
Ctx.setCompilationDir(DebugCompilationDir);
else {
// If no compilation dir is set, try to use the current directory.
SmallString<128> CWD;
if (!sys::fs::current_path(CWD))
Ctx.setCompilationDir(CWD);
}
for (const auto &Arg : DebugPrefixMap) {
const auto &KV = StringRef(Arg).split('=');
Ctx.addDebugPrefixMapEntry(std::string(KV.first), std::string(KV.second));
}
if (!MainFileName.empty())
Ctx.setMainFileName(MainFileName);
if (GenDwarfForAssembly)
Ctx.setGenDwarfRootFile(InputFilename, Buffer->getBuffer());
// Package up features to be passed to target/subtarget
std::string FeaturesStr;
if (MAttrs.size()) {
SubtargetFeatures Features;
for (unsigned i = 0; i != MAttrs.size(); ++i)
Features.AddFeature(MAttrs[i]);
FeaturesStr = Features.getString();
}
sys::fs::OpenFlags Flags = (FileType == OFT_AssemblyFile) ? sys::fs::OF_Text
: sys::fs::OF_None;
std::unique_ptr<ToolOutputFile> Out = GetOutputStream(OutputFilename, Flags);
if (!Out)
return 1;
std::unique_ptr<ToolOutputFile> DwoOut;
if (!SplitDwarfFile.empty()) {
if (FileType != OFT_ObjectFile) {
WithColor::error() << "dwo output only supported with object files\n";
return 1;
}
DwoOut = GetOutputStream(SplitDwarfFile, sys::fs::OF_None);
if (!DwoOut)
return 1;
}
std::unique_ptr<buffer_ostream> BOS;
raw_pwrite_stream *OS = &Out->os();
std::unique_ptr<MCStreamer> Str;
std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
assert(MCII && "Unable to create instruction info!");
std::unique_ptr<MCSubtargetInfo> STI(
TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
assert(STI && "Unable to create subtarget info!");
MCInstPrinter *IP = nullptr;
if (FileType == OFT_AssemblyFile) {
IP = TheTarget->createMCInstPrinter(Triple(TripleName), OutputAsmVariant,
*MAI, *MCII, *MRI);
if (!IP) {
WithColor::error()
<< "unable to create instruction printer for target triple '"
<< TheTriple.normalize() << "' with assembly variant "
<< OutputAsmVariant << ".\n";
return 1;
}
// Set the display preference for hex vs. decimal immediates.
IP->setPrintImmHex(PrintImmHex);
// Set up the AsmStreamer.
std::unique_ptr<MCCodeEmitter> CE;
if (ShowEncoding)
CE.reset(TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
std::unique_ptr<MCAsmBackend> MAB(
TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
auto FOut = std::make_unique<formatted_raw_ostream>(*OS);
Str.reset(
TheTarget->createAsmStreamer(Ctx, std::move(FOut), /*asmverbose*/ true,
/*useDwarfDirectory*/ true, IP,
std::move(CE), std::move(MAB), ShowInst));
} else if (FileType == OFT_Null) {
Str.reset(TheTarget->createNullStreamer(Ctx));
} else {
assert(FileType == OFT_ObjectFile && "Invalid file type!");
if (!Out->os().supportsSeeking()) {
BOS = std::make_unique<buffer_ostream>(Out->os());
OS = BOS.get();
}
MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions);
Str.reset(TheTarget->createMCObjectStreamer(
TheTriple, Ctx, std::unique_ptr<MCAsmBackend>(MAB),
DwoOut ? MAB->createDwoObjectWriter(*OS, DwoOut->os())
: MAB->createObjectWriter(*OS),
std::unique_ptr<MCCodeEmitter>(CE), *STI, MCOptions.MCRelaxAll,
MCOptions.MCIncrementalLinkerCompatible,
/*DWARFMustBeAtTheEnd*/ false));
if (NoExecStack)
Str->InitSections(true);
}
// Use Assembler information for parsing.
Str->setUseAssemblerInfoForParsing(true);
int Res = 1;
bool disassemble = false;
switch (Action) {
case AC_AsLex:
Res = AsLexInput(SrcMgr, *MAI, Out->os());
break;
case AC_Assemble:
Res = AssembleInput(ProgName, TheTarget, SrcMgr, Ctx, *Str, *MAI, *STI,
*MCII, MCOptions);
break;
case AC_MDisassemble:
assert(IP && "Expected assembly output");
IP->setUseMarkup(true);
disassemble = true;
break;
case AC_Disassemble:
disassemble = true;
break;
}
if (disassemble)
Res = Disassembler::disassemble(*TheTarget, TripleName, *STI, *Str, *Buffer,
SrcMgr, Ctx, Out->os(), MCOptions);
// Keep output if no errors.
if (Res == 0) {
Out->keep();
if (DwoOut)
DwoOut->keep();
}
return Res;
}