1 //===-- llvm-mc.cpp - Machine Code Hacking Driver ---------------*- C++ -*-===// 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 utility is a simple driver that allows command line hacking on machine 10 // code. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "Disassembler.h" 15 #include "llvm/MC/MCAsmBackend.h" 16 #include "llvm/MC/MCAsmInfo.h" 17 #include "llvm/MC/MCCodeEmitter.h" 18 #include "llvm/MC/MCContext.h" 19 #include "llvm/MC/MCInstPrinter.h" 20 #include "llvm/MC/MCInstrInfo.h" 21 #include "llvm/MC/MCObjectFileInfo.h" 22 #include "llvm/MC/MCObjectWriter.h" 23 #include "llvm/MC/MCParser/AsmLexer.h" 24 #include "llvm/MC/MCParser/MCTargetAsmParser.h" 25 #include "llvm/MC/MCRegisterInfo.h" 26 #include "llvm/MC/MCStreamer.h" 27 #include "llvm/MC/MCSubtargetInfo.h" 28 #include "llvm/MC/MCTargetOptionsCommandFlags.inc" 29 #include "llvm/Support/CommandLine.h" 30 #include "llvm/Support/Compression.h" 31 #include "llvm/Support/FileUtilities.h" 32 #include "llvm/Support/FormattedStream.h" 33 #include "llvm/Support/Host.h" 34 #include "llvm/Support/InitLLVM.h" 35 #include "llvm/Support/MemoryBuffer.h" 36 #include "llvm/Support/SourceMgr.h" 37 #include "llvm/Support/TargetRegistry.h" 38 #include "llvm/Support/TargetSelect.h" 39 #include "llvm/Support/ToolOutputFile.h" 40 #include "llvm/Support/WithColor.h" 41 42 using namespace llvm; 43 44 static cl::opt<std::string> 45 InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-")); 46 47 static cl::opt<std::string> OutputFilename("o", cl::desc("Output filename"), 48 cl::value_desc("filename"), 49 cl::init("-")); 50 51 static cl::opt<std::string> SplitDwarfFile("split-dwarf-file", 52 cl::desc("DWO output filename"), 53 cl::value_desc("filename")); 54 55 static cl::opt<bool> 56 ShowEncoding("show-encoding", cl::desc("Show instruction encodings")); 57 58 static cl::opt<bool> RelaxELFRel( 59 "relax-relocations", cl::init(true), 60 cl::desc("Emit R_X86_64_GOTPCRELX instead of R_X86_64_GOTPCREL")); 61 62 static cl::opt<DebugCompressionType> CompressDebugSections( 63 "compress-debug-sections", cl::ValueOptional, 64 cl::init(DebugCompressionType::None), 65 cl::desc("Choose DWARF debug sections compression:"), 66 cl::values(clEnumValN(DebugCompressionType::None, "none", "No compression"), 67 clEnumValN(DebugCompressionType::Z, "zlib", 68 "Use zlib compression"), 69 clEnumValN(DebugCompressionType::GNU, "zlib-gnu", 70 "Use zlib-gnu compression (deprecated)"))); 71 72 static cl::opt<bool> 73 ShowInst("show-inst", cl::desc("Show internal instruction representation")); 74 75 static cl::opt<bool> 76 ShowInstOperands("show-inst-operands", 77 cl::desc("Show instructions operands as parsed")); 78 79 static cl::opt<unsigned> 80 OutputAsmVariant("output-asm-variant", 81 cl::desc("Syntax variant to use for output printing")); 82 83 static cl::opt<bool> 84 PrintImmHex("print-imm-hex", cl::init(false), 85 cl::desc("Prefer hex format for immediate values")); 86 87 static cl::list<std::string> 88 DefineSymbol("defsym", cl::desc("Defines a symbol to be an integer constant")); 89 90 static cl::opt<bool> 91 PreserveComments("preserve-comments", 92 cl::desc("Preserve Comments in outputted assembly")); 93 94 enum OutputFileType { 95 OFT_Null, 96 OFT_AssemblyFile, 97 OFT_ObjectFile 98 }; 99 static cl::opt<OutputFileType> 100 FileType("filetype", cl::init(OFT_AssemblyFile), 101 cl::desc("Choose an output file type:"), 102 cl::values( 103 clEnumValN(OFT_AssemblyFile, "asm", 104 "Emit an assembly ('.s') file"), 105 clEnumValN(OFT_Null, "null", 106 "Don't emit anything (for timing purposes)"), 107 clEnumValN(OFT_ObjectFile, "obj", 108 "Emit a native object ('.o') file"))); 109 110 static cl::list<std::string> 111 IncludeDirs("I", cl::desc("Directory of include files"), 112 cl::value_desc("directory"), cl::Prefix); 113 114 static cl::opt<std::string> 115 ArchName("arch", cl::desc("Target arch to assemble for, " 116 "see -version for available targets")); 117 118 static cl::opt<std::string> 119 TripleName("triple", cl::desc("Target triple to assemble for, " 120 "see -version for available targets")); 121 122 static cl::opt<std::string> 123 MCPU("mcpu", 124 cl::desc("Target a specific cpu type (-mcpu=help for details)"), 125 cl::value_desc("cpu-name"), 126 cl::init("")); 127 128 static cl::list<std::string> 129 MAttrs("mattr", 130 cl::CommaSeparated, 131 cl::desc("Target specific attributes (-mattr=help for details)"), 132 cl::value_desc("a1,+a2,-a3,...")); 133 134 static cl::opt<bool> PIC("position-independent", 135 cl::desc("Position independent"), cl::init(false)); 136 137 static cl::opt<bool> 138 LargeCodeModel("large-code-model", 139 cl::desc("Create cfi directives that assume the code might " 140 "be more than 2gb away")); 141 142 static cl::opt<bool> 143 NoInitialTextSection("n", cl::desc("Don't assume assembly file starts " 144 "in the text section")); 145 146 static cl::opt<bool> 147 GenDwarfForAssembly("g", cl::desc("Generate dwarf debugging info for assembly " 148 "source files")); 149 150 static cl::opt<std::string> 151 DebugCompilationDir("fdebug-compilation-dir", 152 cl::desc("Specifies the debug info's compilation dir")); 153 154 static cl::list<std::string> 155 DebugPrefixMap("fdebug-prefix-map", 156 cl::desc("Map file source paths in debug info"), 157 cl::value_desc("= separated key-value pairs")); 158 159 static cl::opt<std::string> 160 MainFileName("main-file-name", 161 cl::desc("Specifies the name we should consider the input file")); 162 163 static cl::opt<bool> SaveTempLabels("save-temp-labels", 164 cl::desc("Don't discard temporary labels")); 165 166 static cl::opt<bool> LexMasmIntegers( 167 "masm-integers", 168 cl::desc("Enable binary and hex masm integers (0b110 and 0ABCh)")); 169 170 static cl::opt<bool> NoExecStack("no-exec-stack", 171 cl::desc("File doesn't need an exec stack")); 172 173 enum ActionType { 174 AC_AsLex, 175 AC_Assemble, 176 AC_Disassemble, 177 AC_MDisassemble, 178 }; 179 180 static cl::opt<ActionType> 181 Action(cl::desc("Action to perform:"), 182 cl::init(AC_Assemble), 183 cl::values(clEnumValN(AC_AsLex, "as-lex", 184 "Lex tokens from a .s file"), 185 clEnumValN(AC_Assemble, "assemble", 186 "Assemble a .s file (default)"), 187 clEnumValN(AC_Disassemble, "disassemble", 188 "Disassemble strings of hex bytes"), 189 clEnumValN(AC_MDisassemble, "mdis", 190 "Marked up disassembly of strings of hex bytes"))); 191 192 static const Target *GetTarget(const char *ProgName) { 193 // Figure out the target triple. 194 if (TripleName.empty()) 195 TripleName = sys::getDefaultTargetTriple(); 196 Triple TheTriple(Triple::normalize(TripleName)); 197 198 // Get the target specific parser. 199 std::string Error; 200 const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple, 201 Error); 202 if (!TheTarget) { 203 WithColor::error(errs(), ProgName) << Error; 204 return nullptr; 205 } 206 207 // Update the triple name and return the found target. 208 TripleName = TheTriple.getTriple(); 209 return TheTarget; 210 } 211 212 static std::unique_ptr<ToolOutputFile> GetOutputStream(StringRef Path) { 213 std::error_code EC; 214 auto Out = llvm::make_unique<ToolOutputFile>(Path, EC, sys::fs::F_None); 215 if (EC) { 216 WithColor::error() << EC.message() << '\n'; 217 return nullptr; 218 } 219 220 return Out; 221 } 222 223 static std::string DwarfDebugFlags; 224 static void setDwarfDebugFlags(int argc, char **argv) { 225 if (!getenv("RC_DEBUG_OPTIONS")) 226 return; 227 for (int i = 0; i < argc; i++) { 228 DwarfDebugFlags += argv[i]; 229 if (i + 1 < argc) 230 DwarfDebugFlags += " "; 231 } 232 } 233 234 static std::string DwarfDebugProducer; 235 static void setDwarfDebugProducer() { 236 if(!getenv("DEBUG_PRODUCER")) 237 return; 238 DwarfDebugProducer += getenv("DEBUG_PRODUCER"); 239 } 240 241 static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI, 242 raw_ostream &OS) { 243 244 AsmLexer Lexer(MAI); 245 Lexer.setBuffer(SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer()); 246 247 bool Error = false; 248 while (Lexer.Lex().isNot(AsmToken::Eof)) { 249 Lexer.getTok().dump(OS); 250 OS << "\n"; 251 if (Lexer.getTok().getKind() == AsmToken::Error) 252 Error = true; 253 } 254 255 return Error; 256 } 257 258 static int fillCommandLineSymbols(MCAsmParser &Parser) { 259 for (auto &I: DefineSymbol) { 260 auto Pair = StringRef(I).split('='); 261 auto Sym = Pair.first; 262 auto Val = Pair.second; 263 264 if (Sym.empty() || Val.empty()) { 265 WithColor::error() << "defsym must be of the form: sym=value: " << I 266 << "\n"; 267 return 1; 268 } 269 int64_t Value; 270 if (Val.getAsInteger(0, Value)) { 271 WithColor::error() << "value is not an integer: " << Val << "\n"; 272 return 1; 273 } 274 Parser.getContext().setSymbolValue(Parser.getStreamer(), Sym, Value); 275 } 276 return 0; 277 } 278 279 static int AssembleInput(const char *ProgName, const Target *TheTarget, 280 SourceMgr &SrcMgr, MCContext &Ctx, MCStreamer &Str, 281 MCAsmInfo &MAI, MCSubtargetInfo &STI, 282 MCInstrInfo &MCII, MCTargetOptions &MCOptions) { 283 std::unique_ptr<MCAsmParser> Parser( 284 createMCAsmParser(SrcMgr, Ctx, Str, MAI)); 285 std::unique_ptr<MCTargetAsmParser> TAP( 286 TheTarget->createMCAsmParser(STI, *Parser, MCII, MCOptions)); 287 288 if (!TAP) { 289 WithColor::error(errs(), ProgName) 290 << "this target does not support assembly parsing.\n"; 291 return 1; 292 } 293 294 int SymbolResult = fillCommandLineSymbols(*Parser); 295 if(SymbolResult) 296 return SymbolResult; 297 Parser->setShowParsedOperands(ShowInstOperands); 298 Parser->setTargetParser(*TAP); 299 Parser->getLexer().setLexMasmIntegers(LexMasmIntegers); 300 301 int Res = Parser->Run(NoInitialTextSection); 302 303 return Res; 304 } 305 306 int main(int argc, char **argv) { 307 InitLLVM X(argc, argv); 308 309 // Initialize targets and assembly printers/parsers. 310 llvm::InitializeAllTargetInfos(); 311 llvm::InitializeAllTargetMCs(); 312 llvm::InitializeAllAsmParsers(); 313 llvm::InitializeAllDisassemblers(); 314 315 // Register the target printer for --version. 316 cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion); 317 318 cl::ParseCommandLineOptions(argc, argv, "llvm machine code playground\n"); 319 MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags(); 320 setDwarfDebugFlags(argc, argv); 321 322 setDwarfDebugProducer(); 323 324 const char *ProgName = argv[0]; 325 const Target *TheTarget = GetTarget(ProgName); 326 if (!TheTarget) 327 return 1; 328 // Now that GetTarget() has (potentially) replaced TripleName, it's safe to 329 // construct the Triple object. 330 Triple TheTriple(TripleName); 331 332 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr = 333 MemoryBuffer::getFileOrSTDIN(InputFilename); 334 if (std::error_code EC = BufferPtr.getError()) { 335 WithColor::error(errs(), ProgName) 336 << InputFilename << ": " << EC.message() << '\n'; 337 return 1; 338 } 339 MemoryBuffer *Buffer = BufferPtr->get(); 340 341 SourceMgr SrcMgr; 342 343 // Tell SrcMgr about this buffer, which is what the parser will pick up. 344 SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc()); 345 346 // Record the location of the include directories so that the lexer can find 347 // it later. 348 SrcMgr.setIncludeDirs(IncludeDirs); 349 350 std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName)); 351 assert(MRI && "Unable to create target register info!"); 352 353 std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName)); 354 assert(MAI && "Unable to create target asm info!"); 355 356 MAI->setRelaxELFRelocations(RelaxELFRel); 357 358 if (CompressDebugSections != DebugCompressionType::None) { 359 if (!zlib::isAvailable()) { 360 WithColor::error(errs(), ProgName) 361 << "build tools with zlib to enable -compress-debug-sections"; 362 return 1; 363 } 364 MAI->setCompressDebugSections(CompressDebugSections); 365 } 366 MAI->setPreserveAsmComments(PreserveComments); 367 368 // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and 369 // MCObjectFileInfo needs a MCContext reference in order to initialize itself. 370 MCObjectFileInfo MOFI; 371 MCContext Ctx(MAI.get(), MRI.get(), &MOFI, &SrcMgr); 372 MOFI.InitMCObjectFileInfo(TheTriple, PIC, Ctx, LargeCodeModel); 373 374 if (SaveTempLabels) 375 Ctx.setAllowTemporaryLabels(false); 376 377 Ctx.setGenDwarfForAssembly(GenDwarfForAssembly); 378 // Default to 4 for dwarf version. 379 unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4; 380 if (DwarfVersion < 2 || DwarfVersion > 5) { 381 errs() << ProgName << ": Dwarf version " << DwarfVersion 382 << " is not supported." << '\n'; 383 return 1; 384 } 385 Ctx.setDwarfVersion(DwarfVersion); 386 if (!DwarfDebugFlags.empty()) 387 Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags)); 388 if (!DwarfDebugProducer.empty()) 389 Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer)); 390 if (!DebugCompilationDir.empty()) 391 Ctx.setCompilationDir(DebugCompilationDir); 392 else { 393 // If no compilation dir is set, try to use the current directory. 394 SmallString<128> CWD; 395 if (!sys::fs::current_path(CWD)) 396 Ctx.setCompilationDir(CWD); 397 } 398 for (const auto &Arg : DebugPrefixMap) { 399 const auto &KV = StringRef(Arg).split('='); 400 Ctx.addDebugPrefixMapEntry(KV.first, KV.second); 401 } 402 if (!MainFileName.empty()) 403 Ctx.setMainFileName(MainFileName); 404 if (GenDwarfForAssembly) 405 Ctx.setGenDwarfRootFile(InputFilename, Buffer->getBuffer()); 406 407 // Package up features to be passed to target/subtarget 408 std::string FeaturesStr; 409 if (MAttrs.size()) { 410 SubtargetFeatures Features; 411 for (unsigned i = 0; i != MAttrs.size(); ++i) 412 Features.AddFeature(MAttrs[i]); 413 FeaturesStr = Features.getString(); 414 } 415 416 std::unique_ptr<ToolOutputFile> Out = GetOutputStream(OutputFilename); 417 if (!Out) 418 return 1; 419 420 std::unique_ptr<ToolOutputFile> DwoOut; 421 if (!SplitDwarfFile.empty()) { 422 if (FileType != OFT_ObjectFile) { 423 WithColor::error() << "dwo output only supported with object files\n"; 424 return 1; 425 } 426 DwoOut = GetOutputStream(SplitDwarfFile); 427 if (!DwoOut) 428 return 1; 429 } 430 431 std::unique_ptr<buffer_ostream> BOS; 432 raw_pwrite_stream *OS = &Out->os(); 433 std::unique_ptr<MCStreamer> Str; 434 435 std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo()); 436 std::unique_ptr<MCSubtargetInfo> STI( 437 TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr)); 438 439 MCInstPrinter *IP = nullptr; 440 if (FileType == OFT_AssemblyFile) { 441 IP = TheTarget->createMCInstPrinter(Triple(TripleName), OutputAsmVariant, 442 *MAI, *MCII, *MRI); 443 444 if (!IP) { 445 WithColor::error() 446 << "unable to create instruction printer for target triple '" 447 << TheTriple.normalize() << "' with assembly variant " 448 << OutputAsmVariant << ".\n"; 449 return 1; 450 } 451 452 // Set the display preference for hex vs. decimal immediates. 453 IP->setPrintImmHex(PrintImmHex); 454 455 // Set up the AsmStreamer. 456 std::unique_ptr<MCCodeEmitter> CE; 457 if (ShowEncoding) 458 CE.reset(TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx)); 459 460 std::unique_ptr<MCAsmBackend> MAB( 461 TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions)); 462 auto FOut = llvm::make_unique<formatted_raw_ostream>(*OS); 463 Str.reset( 464 TheTarget->createAsmStreamer(Ctx, std::move(FOut), /*asmverbose*/ true, 465 /*useDwarfDirectory*/ true, IP, 466 std::move(CE), std::move(MAB), ShowInst)); 467 468 } else if (FileType == OFT_Null) { 469 Str.reset(TheTarget->createNullStreamer(Ctx)); 470 } else { 471 assert(FileType == OFT_ObjectFile && "Invalid file type!"); 472 473 // Don't waste memory on names of temp labels. 474 Ctx.setUseNamesOnTempLabels(false); 475 476 if (!Out->os().supportsSeeking()) { 477 BOS = make_unique<buffer_ostream>(Out->os()); 478 OS = BOS.get(); 479 } 480 481 MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx); 482 MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions); 483 Str.reset(TheTarget->createMCObjectStreamer( 484 TheTriple, Ctx, std::unique_ptr<MCAsmBackend>(MAB), 485 DwoOut ? MAB->createDwoObjectWriter(*OS, DwoOut->os()) 486 : MAB->createObjectWriter(*OS), 487 std::unique_ptr<MCCodeEmitter>(CE), *STI, MCOptions.MCRelaxAll, 488 MCOptions.MCIncrementalLinkerCompatible, 489 /*DWARFMustBeAtTheEnd*/ false)); 490 if (NoExecStack) 491 Str->InitSections(true); 492 } 493 494 // Use Assembler information for parsing. 495 Str->setUseAssemblerInfoForParsing(true); 496 497 int Res = 1; 498 bool disassemble = false; 499 switch (Action) { 500 case AC_AsLex: 501 Res = AsLexInput(SrcMgr, *MAI, Out->os()); 502 break; 503 case AC_Assemble: 504 Res = AssembleInput(ProgName, TheTarget, SrcMgr, Ctx, *Str, *MAI, *STI, 505 *MCII, MCOptions); 506 break; 507 case AC_MDisassemble: 508 assert(IP && "Expected assembly output"); 509 IP->setUseMarkup(1); 510 disassemble = true; 511 break; 512 case AC_Disassemble: 513 disassemble = true; 514 break; 515 } 516 if (disassemble) 517 Res = Disassembler::disassemble(*TheTarget, TripleName, *STI, *Str, 518 *Buffer, SrcMgr, Out->os()); 519 520 // Keep output if no errors. 521 if (Res == 0) { 522 Out->keep(); 523 if (DwoOut) 524 DwoOut->keep(); 525 } 526 return Res; 527 } 528