tools/llvm-mc/llvm-mc.cpp

   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     sys::fs::OpenFlags Flags) {
 214   std::error_code EC;
 215   auto Out = std::make_unique<ToolOutputFile>(Path, EC, Flags);
 216   if (EC) {
 217     WithColor::error() << EC.message() << '\n';
 218     return nullptr;
 219   }
 220
 221   return Out;
 222 }
 223
 224 static std::string DwarfDebugFlags;
 225 static void setDwarfDebugFlags(int argc, char **argv) {
 226   if (!getenv("RC_DEBUG_OPTIONS"))
 227     return;
 228   for (int i = 0; i < argc; i++) {
 229     DwarfDebugFlags += argv[i];
 230     if (i + 1 < argc)
 231       DwarfDebugFlags += " ";
 232   }
 233 }
 234
 235 static std::string DwarfDebugProducer;
 236 static void setDwarfDebugProducer() {
 237   if(!getenv("DEBUG_PRODUCER"))
 238     return;
 239   DwarfDebugProducer += getenv("DEBUG_PRODUCER");
 240 }
 241
 242 static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI,
 243                       raw_ostream &OS) {
 244
 245   AsmLexer Lexer(MAI);
 246   Lexer.setBuffer(SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer());
 247
 248   bool Error = false;
 249   while (Lexer.Lex().isNot(AsmToken::Eof)) {
 250     Lexer.getTok().dump(OS);
 251     OS << "\n";
 252     if (Lexer.getTok().getKind() == AsmToken::Error)
 253       Error = true;
 254   }
 255
 256   return Error;
 257 }
 258
 259 static int fillCommandLineSymbols(MCAsmParser &Parser) {
 260   for (auto &I: DefineSymbol) {
 261     auto Pair = StringRef(I).split('=');
 262     auto Sym = Pair.first;
 263     auto Val = Pair.second;
 264
 265     if (Sym.empty() || Val.empty()) {
 266       WithColor::error() << "defsym must be of the form: sym=value: " << I
 267                          << "\n";
 268       return 1;
 269     }
 270     int64_t Value;
 271     if (Val.getAsInteger(0, Value)) {
 272       WithColor::error() << "value is not an integer: " << Val << "\n";
 273       return 1;
 274     }
 275     Parser.getContext().setSymbolValue(Parser.getStreamer(), Sym, Value);
 276   }
 277   return 0;
 278 }
 279
 280 static int AssembleInput(const char *ProgName, const Target *TheTarget,
 281                          SourceMgr &SrcMgr, MCContext &Ctx, MCStreamer &Str,
 282                          MCAsmInfo &MAI, MCSubtargetInfo &STI,
 283                          MCInstrInfo &MCII, MCTargetOptions const &MCOptions) {
 284   std::unique_ptr<MCAsmParser> Parser(
 285       createMCAsmParser(SrcMgr, Ctx, Str, MAI));
 286   std::unique_ptr<MCTargetAsmParser> TAP(
 287       TheTarget->createMCAsmParser(STI, *Parser, MCII, MCOptions));
 288
 289   if (!TAP) {
 290     WithColor::error(errs(), ProgName)
 291         << "this target does not support assembly parsing.\n";
 292     return 1;
 293   }
 294
 295   int SymbolResult = fillCommandLineSymbols(*Parser);
 296   if(SymbolResult)
 297     return SymbolResult;
 298   Parser->setShowParsedOperands(ShowInstOperands);
 299   Parser->setTargetParser(*TAP);
 300   Parser->getLexer().setLexMasmIntegers(LexMasmIntegers);
 301
 302   int Res = Parser->Run(NoInitialTextSection);
 303
 304   return Res;
 305 }
 306
 307 int main(int argc, char **argv) {
 308   InitLLVM X(argc, argv);
 309
 310   // Initialize targets and assembly printers/parsers.
 311   llvm::InitializeAllTargetInfos();
 312   llvm::InitializeAllTargetMCs();
 313   llvm::InitializeAllAsmParsers();
 314   llvm::InitializeAllDisassemblers();
 315
 316   // Register the target printer for --version.
 317   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
 318
 319   cl::ParseCommandLineOptions(argc, argv, "llvm machine code playground\n");
 320   const MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
 321   setDwarfDebugFlags(argc, argv);
 322
 323   setDwarfDebugProducer();
 324
 325   const char *ProgName = argv[0];
 326   const Target *TheTarget = GetTarget(ProgName);
 327   if (!TheTarget)
 328     return 1;
 329   // Now that GetTarget() has (potentially) replaced TripleName, it's safe to
 330   // construct the Triple object.
 331   Triple TheTriple(TripleName);
 332
 333   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
 334       MemoryBuffer::getFileOrSTDIN(InputFilename);
 335   if (std::error_code EC = BufferPtr.getError()) {
 336     WithColor::error(errs(), ProgName)
 337         << InputFilename << ": " << EC.message() << '\n';
 338     return 1;
 339   }
 340   MemoryBuffer *Buffer = BufferPtr->get();
 341
 342   SourceMgr SrcMgr;
 343
 344   // Tell SrcMgr about this buffer, which is what the parser will pick up.
 345   SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
 346
 347   // Record the location of the include directories so that the lexer can find
 348   // it later.
 349   SrcMgr.setIncludeDirs(IncludeDirs);
 350
 351   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
 352   assert(MRI && "Unable to create target register info!");
 353
 354   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
 355   assert(MAI && "Unable to create target asm info!");
 356
 357   MAI->setRelaxELFRelocations(RelaxELFRel);
 358
 359   if (CompressDebugSections != DebugCompressionType::None) {
 360     if (!zlib::isAvailable()) {
 361       WithColor::error(errs(), ProgName)
 362           << "build tools with zlib to enable -compress-debug-sections";
 363       return 1;
 364     }
 365     MAI->setCompressDebugSections(CompressDebugSections);
 366   }
 367   MAI->setPreserveAsmComments(PreserveComments);
 368
 369   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
 370   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
 371   MCObjectFileInfo MOFI;
 372   MCContext Ctx(MAI.get(), MRI.get(), &MOFI, &SrcMgr, &MCOptions);
 373   MOFI.InitMCObjectFileInfo(TheTriple, PIC, Ctx, LargeCodeModel);
 374
 375   if (SaveTempLabels)
 376     Ctx.setAllowTemporaryLabels(false);
 377
 378   Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
 379   // Default to 4 for dwarf version.
 380   unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4;
 381   if (DwarfVersion < 2 || DwarfVersion > 5) {
 382     errs() << ProgName << ": Dwarf version " << DwarfVersion
 383            << " is not supported." << '\n';
 384     return 1;
 385   }
 386   Ctx.setDwarfVersion(DwarfVersion);
 387   if (!DwarfDebugFlags.empty())
 388     Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
 389   if (!DwarfDebugProducer.empty())
 390     Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer));
 391   if (!DebugCompilationDir.empty())
 392     Ctx.setCompilationDir(DebugCompilationDir);
 393   else {
 394     // If no compilation dir is set, try to use the current directory.
 395     SmallString<128> CWD;
 396     if (!sys::fs::current_path(CWD))
 397       Ctx.setCompilationDir(CWD);
 398   }
 399   for (const auto &Arg : DebugPrefixMap) {
 400     const auto &KV = StringRef(Arg).split('=');
 401     Ctx.addDebugPrefixMapEntry(KV.first, KV.second);
 402   }
 403   if (!MainFileName.empty())
 404     Ctx.setMainFileName(MainFileName);
 405   if (GenDwarfForAssembly)
 406     Ctx.setGenDwarfRootFile(InputFilename, Buffer->getBuffer());
 407
 408   // Package up features to be passed to target/subtarget
 409   std::string FeaturesStr;
 410   if (MAttrs.size()) {
 411     SubtargetFeatures Features;
 412     for (unsigned i = 0; i != MAttrs.size(); ++i)
 413       Features.AddFeature(MAttrs[i]);
 414     FeaturesStr = Features.getString();
 415   }
 416
 417   sys::fs::OpenFlags Flags = (FileType == OFT_AssemblyFile) ? sys::fs::OF_Text
 418                                                             : sys::fs::OF_None;
 419   std::unique_ptr<ToolOutputFile> Out = GetOutputStream(OutputFilename, Flags);
 420   if (!Out)
 421     return 1;
 422
 423   std::unique_ptr<ToolOutputFile> DwoOut;
 424   if (!SplitDwarfFile.empty()) {
 425     if (FileType != OFT_ObjectFile) {
 426       WithColor::error() << "dwo output only supported with object files\n";
 427       return 1;
 428     }
 429     DwoOut = GetOutputStream(SplitDwarfFile, sys::fs::OF_None);
 430     if (!DwoOut)
 431       return 1;
 432   }
 433
 434   std::unique_ptr<buffer_ostream> BOS;
 435   raw_pwrite_stream *OS = &Out->os();
 436   std::unique_ptr<MCStreamer> Str;
 437
 438   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
 439   std::unique_ptr<MCSubtargetInfo> STI(
 440       TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
 441
 442   MCInstPrinter *IP = nullptr;
 443   if (FileType == OFT_AssemblyFile) {
 444     IP = TheTarget->createMCInstPrinter(Triple(TripleName), OutputAsmVariant,
 445                                         *MAI, *MCII, *MRI);
 446
 447     if (!IP) {
 448       WithColor::error()
 449           << "unable to create instruction printer for target triple '"
 450           << TheTriple.normalize() << "' with assembly variant "
 451           << OutputAsmVariant << ".\n";
 452       return 1;
 453     }
 454
 455     // Set the display preference for hex vs. decimal immediates.
 456     IP->setPrintImmHex(PrintImmHex);
 457
 458     // Set up the AsmStreamer.
 459     std::unique_ptr<MCCodeEmitter> CE;
 460     if (ShowEncoding)
 461       CE.reset(TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
 462
 463     std::unique_ptr<MCAsmBackend> MAB(
 464         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
 465     auto FOut = std::make_unique<formatted_raw_ostream>(*OS);
 466     Str.reset(
 467         TheTarget->createAsmStreamer(Ctx, std::move(FOut), /*asmverbose*/ true,
 468                                      /*useDwarfDirectory*/ true, IP,
 469                                      std::move(CE), std::move(MAB), ShowInst));
 470
 471   } else if (FileType == OFT_Null) {
 472     Str.reset(TheTarget->createNullStreamer(Ctx));
 473   } else {
 474     assert(FileType == OFT_ObjectFile && "Invalid file type!");
 475
 476     // Don't waste memory on names of temp labels.
 477     Ctx.setUseNamesOnTempLabels(false);
 478
 479     if (!Out->os().supportsSeeking()) {
 480       BOS = std::make_unique<buffer_ostream>(Out->os());
 481       OS = BOS.get();
 482     }
 483
 484     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
 485     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions);
 486     Str.reset(TheTarget->createMCObjectStreamer(
 487         TheTriple, Ctx, std::unique_ptr<MCAsmBackend>(MAB),
 488         DwoOut ? MAB->createDwoObjectWriter(*OS, DwoOut->os())
 489                : MAB->createObjectWriter(*OS),
 490         std::unique_ptr<MCCodeEmitter>(CE), *STI, MCOptions.MCRelaxAll,
 491         MCOptions.MCIncrementalLinkerCompatible,
 492         /*DWARFMustBeAtTheEnd*/ false));
 493     if (NoExecStack)
 494       Str->InitSections(true);
 495   }
 496
 497   // Use Assembler information for parsing.
 498   Str->setUseAssemblerInfoForParsing(true);
 499
 500   int Res = 1;
 501   bool disassemble = false;
 502   switch (Action) {
 503   case AC_AsLex:
 504     Res = AsLexInput(SrcMgr, *MAI, Out->os());
 505     break;
 506   case AC_Assemble:
 507     Res = AssembleInput(ProgName, TheTarget, SrcMgr, Ctx, *Str, *MAI, *STI,
 508                         *MCII, MCOptions);
 509     break;
 510   case AC_MDisassemble:
 511     assert(IP && "Expected assembly output");
 512     IP->setUseMarkup(true);
 513     disassemble = true;
 514     break;
 515   case AC_Disassemble:
 516     disassemble = true;
 517     break;
 518   }
 519   if (disassemble)
 520     Res = Disassembler::disassemble(*TheTarget, TripleName, *STI, *Str, *Buffer,
 521                                     SrcMgr, Ctx, Out->os());
 522
 523   // Keep output if no errors.
 524   if (Res == 0) {
 525     Out->keep();
 526     if (DwoOut)
 527       DwoOut->keep();
 528   }
 529   return Res;
 530 }