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      1 //===-- llvm-mc.cpp - Machine Code Hacking Driver -------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This utility is a simple driver that allows command line hacking on machine
     11 // code.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "Disassembler.h"
     16 #include "llvm/MC/MCAsmBackend.h"
     17 #include "llvm/MC/MCAsmInfo.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/MCParser/AsmLexer.h"
     23 #include "llvm/MC/MCRegisterInfo.h"
     24 #include "llvm/MC/MCSectionMachO.h"
     25 #include "llvm/MC/MCStreamer.h"
     26 #include "llvm/MC/MCSubtargetInfo.h"
     27 #include "llvm/MC/MCTargetAsmParser.h"
     28 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
     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/ManagedStatic.h"
     35 #include "llvm/Support/MemoryBuffer.h"
     36 #include "llvm/Support/PrettyStackTrace.h"
     37 #include "llvm/Support/Signals.h"
     38 #include "llvm/Support/SourceMgr.h"
     39 #include "llvm/Support/TargetRegistry.h"
     40 #include "llvm/Support/TargetSelect.h"
     41 #include "llvm/Support/ToolOutputFile.h"
     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>
     48 OutputFilename("o", cl::desc("Output filename"),
     49                cl::value_desc("filename"));
     50 
     51 static cl::opt<bool>
     52 ShowEncoding("show-encoding", cl::desc("Show instruction encodings"));
     53 
     54 static cl::opt<bool>
     55 CompressDebugSections("compress-debug-sections",
     56                       cl::desc("Compress DWARF debug sections"));
     57 
     58 static cl::opt<bool>
     59 ShowInst("show-inst", cl::desc("Show internal instruction representation"));
     60 
     61 static cl::opt<bool>
     62 ShowInstOperands("show-inst-operands",
     63                  cl::desc("Show instructions operands as parsed"));
     64 
     65 static cl::opt<unsigned>
     66 OutputAsmVariant("output-asm-variant",
     67                  cl::desc("Syntax variant to use for output printing"));
     68 
     69 static cl::opt<bool>
     70 PrintImmHex("print-imm-hex", cl::init(false),
     71             cl::desc("Prefer hex format for immediate values"));
     72 
     73 enum OutputFileType {
     74   OFT_Null,
     75   OFT_AssemblyFile,
     76   OFT_ObjectFile
     77 };
     78 static cl::opt<OutputFileType>
     79 FileType("filetype", cl::init(OFT_AssemblyFile),
     80   cl::desc("Choose an output file type:"),
     81   cl::values(
     82        clEnumValN(OFT_AssemblyFile, "asm",
     83                   "Emit an assembly ('.s') file"),
     84        clEnumValN(OFT_Null, "null",
     85                   "Don't emit anything (for timing purposes)"),
     86        clEnumValN(OFT_ObjectFile, "obj",
     87                   "Emit a native object ('.o') file"),
     88        clEnumValEnd));
     89 
     90 static cl::list<std::string>
     91 IncludeDirs("I", cl::desc("Directory of include files"),
     92             cl::value_desc("directory"), cl::Prefix);
     93 
     94 static cl::opt<std::string>
     95 ArchName("arch", cl::desc("Target arch to assemble for, "
     96                           "see -version for available targets"));
     97 
     98 static cl::opt<std::string>
     99 TripleName("triple", cl::desc("Target triple to assemble for, "
    100                               "see -version for available targets"));
    101 
    102 static cl::opt<std::string>
    103 MCPU("mcpu",
    104      cl::desc("Target a specific cpu type (-mcpu=help for details)"),
    105      cl::value_desc("cpu-name"),
    106      cl::init(""));
    107 
    108 static cl::list<std::string>
    109 MAttrs("mattr",
    110   cl::CommaSeparated,
    111   cl::desc("Target specific attributes (-mattr=help for details)"),
    112   cl::value_desc("a1,+a2,-a3,..."));
    113 
    114 static cl::opt<Reloc::Model>
    115 RelocModel("relocation-model",
    116              cl::desc("Choose relocation model"),
    117              cl::init(Reloc::Default),
    118              cl::values(
    119             clEnumValN(Reloc::Default, "default",
    120                        "Target default relocation model"),
    121             clEnumValN(Reloc::Static, "static",
    122                        "Non-relocatable code"),
    123             clEnumValN(Reloc::PIC_, "pic",
    124                        "Fully relocatable, position independent code"),
    125             clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
    126                        "Relocatable external references, non-relocatable code"),
    127             clEnumValEnd));
    128 
    129 static cl::opt<llvm::CodeModel::Model>
    130 CMModel("code-model",
    131         cl::desc("Choose code model"),
    132         cl::init(CodeModel::Default),
    133         cl::values(clEnumValN(CodeModel::Default, "default",
    134                               "Target default code model"),
    135                    clEnumValN(CodeModel::Small, "small",
    136                               "Small code model"),
    137                    clEnumValN(CodeModel::Kernel, "kernel",
    138                               "Kernel code model"),
    139                    clEnumValN(CodeModel::Medium, "medium",
    140                               "Medium code model"),
    141                    clEnumValN(CodeModel::Large, "large",
    142                               "Large code model"),
    143                    clEnumValEnd));
    144 
    145 static cl::opt<bool>
    146 NoInitialTextSection("n", cl::desc("Don't assume assembly file starts "
    147                                    "in the text section"));
    148 
    149 static cl::opt<bool>
    150 GenDwarfForAssembly("g", cl::desc("Generate dwarf debugging info for assembly "
    151                                   "source files"));
    152 
    153 static cl::opt<std::string>
    154 DebugCompilationDir("fdebug-compilation-dir",
    155                     cl::desc("Specifies the debug info's compilation dir"));
    156 
    157 static cl::opt<std::string>
    158 MainFileName("main-file-name",
    159              cl::desc("Specifies the name we should consider the input file"));
    160 
    161 static cl::opt<bool> SaveTempLabels("save-temp-labels",
    162                                     cl::desc("Don't discard temporary labels"));
    163 
    164 static cl::opt<bool> NoExecStack("no-exec-stack",
    165                                  cl::desc("File doesn't need an exec stack"));
    166 
    167 enum ActionType {
    168   AC_AsLex,
    169   AC_Assemble,
    170   AC_Disassemble,
    171   AC_MDisassemble,
    172 };
    173 
    174 static cl::opt<ActionType>
    175 Action(cl::desc("Action to perform:"),
    176        cl::init(AC_Assemble),
    177        cl::values(clEnumValN(AC_AsLex, "as-lex",
    178                              "Lex tokens from a .s file"),
    179                   clEnumValN(AC_Assemble, "assemble",
    180                              "Assemble a .s file (default)"),
    181                   clEnumValN(AC_Disassemble, "disassemble",
    182                              "Disassemble strings of hex bytes"),
    183                   clEnumValN(AC_MDisassemble, "mdis",
    184                              "Marked up disassembly of strings of hex bytes"),
    185                   clEnumValEnd));
    186 
    187 static const Target *GetTarget(const char *ProgName) {
    188   // Figure out the target triple.
    189   if (TripleName.empty())
    190     TripleName = sys::getDefaultTargetTriple();
    191   Triple TheTriple(Triple::normalize(TripleName));
    192 
    193   // Get the target specific parser.
    194   std::string Error;
    195   const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple,
    196                                                          Error);
    197   if (!TheTarget) {
    198     errs() << ProgName << ": " << Error;
    199     return nullptr;
    200   }
    201 
    202   // Update the triple name and return the found target.
    203   TripleName = TheTriple.getTriple();
    204   return TheTarget;
    205 }
    206 
    207 static tool_output_file *GetOutputStream() {
    208   if (OutputFilename == "")
    209     OutputFilename = "-";
    210 
    211   std::string Err;
    212   tool_output_file *Out =
    213       new tool_output_file(OutputFilename.c_str(), Err, sys::fs::F_None);
    214   if (!Err.empty()) {
    215     errs() << Err << '\n';
    216     delete Out;
    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(void) {
    236   if(!getenv("DEBUG_PRODUCER"))
    237     return;
    238   DwarfDebugProducer += getenv("DEBUG_PRODUCER");
    239 }
    240 
    241 static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI,
    242                       tool_output_file *Out) {
    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     AsmToken Tok = Lexer.getTok();
    250 
    251     switch (Tok.getKind()) {
    252     default:
    253       SrcMgr.PrintMessage(Lexer.getLoc(), SourceMgr::DK_Warning,
    254                           "unknown token");
    255       Error = true;
    256       break;
    257     case AsmToken::Error:
    258       Error = true; // error already printed.
    259       break;
    260     case AsmToken::Identifier:
    261       Out->os() << "identifier: " << Lexer.getTok().getString();
    262       break;
    263     case AsmToken::Integer:
    264       Out->os() << "int: " << Lexer.getTok().getString();
    265       break;
    266     case AsmToken::Real:
    267       Out->os() << "real: " << Lexer.getTok().getString();
    268       break;
    269     case AsmToken::String:
    270       Out->os() << "string: " << Lexer.getTok().getString();
    271       break;
    272 
    273     case AsmToken::Amp:            Out->os() << "Amp"; break;
    274     case AsmToken::AmpAmp:         Out->os() << "AmpAmp"; break;
    275     case AsmToken::At:             Out->os() << "At"; break;
    276     case AsmToken::Caret:          Out->os() << "Caret"; break;
    277     case AsmToken::Colon:          Out->os() << "Colon"; break;
    278     case AsmToken::Comma:          Out->os() << "Comma"; break;
    279     case AsmToken::Dollar:         Out->os() << "Dollar"; break;
    280     case AsmToken::Dot:            Out->os() << "Dot"; break;
    281     case AsmToken::EndOfStatement: Out->os() << "EndOfStatement"; break;
    282     case AsmToken::Eof:            Out->os() << "Eof"; break;
    283     case AsmToken::Equal:          Out->os() << "Equal"; break;
    284     case AsmToken::EqualEqual:     Out->os() << "EqualEqual"; break;
    285     case AsmToken::Exclaim:        Out->os() << "Exclaim"; break;
    286     case AsmToken::ExclaimEqual:   Out->os() << "ExclaimEqual"; break;
    287     case AsmToken::Greater:        Out->os() << "Greater"; break;
    288     case AsmToken::GreaterEqual:   Out->os() << "GreaterEqual"; break;
    289     case AsmToken::GreaterGreater: Out->os() << "GreaterGreater"; break;
    290     case AsmToken::Hash:           Out->os() << "Hash"; break;
    291     case AsmToken::LBrac:          Out->os() << "LBrac"; break;
    292     case AsmToken::LCurly:         Out->os() << "LCurly"; break;
    293     case AsmToken::LParen:         Out->os() << "LParen"; break;
    294     case AsmToken::Less:           Out->os() << "Less"; break;
    295     case AsmToken::LessEqual:      Out->os() << "LessEqual"; break;
    296     case AsmToken::LessGreater:    Out->os() << "LessGreater"; break;
    297     case AsmToken::LessLess:       Out->os() << "LessLess"; break;
    298     case AsmToken::Minus:          Out->os() << "Minus"; break;
    299     case AsmToken::Percent:        Out->os() << "Percent"; break;
    300     case AsmToken::Pipe:           Out->os() << "Pipe"; break;
    301     case AsmToken::PipePipe:       Out->os() << "PipePipe"; break;
    302     case AsmToken::Plus:           Out->os() << "Plus"; break;
    303     case AsmToken::RBrac:          Out->os() << "RBrac"; break;
    304     case AsmToken::RCurly:         Out->os() << "RCurly"; break;
    305     case AsmToken::RParen:         Out->os() << "RParen"; break;
    306     case AsmToken::Slash:          Out->os() << "Slash"; break;
    307     case AsmToken::Star:           Out->os() << "Star"; break;
    308     case AsmToken::Tilde:          Out->os() << "Tilde"; break;
    309     }
    310 
    311     // Print the token string.
    312     Out->os() << " (\"";
    313     Out->os().write_escaped(Tok.getString());
    314     Out->os() << "\")\n";
    315   }
    316 
    317   return Error;
    318 }
    319 
    320 static int AssembleInput(const char *ProgName, const Target *TheTarget,
    321                          SourceMgr &SrcMgr, MCContext &Ctx, MCStreamer &Str,
    322                          MCAsmInfo &MAI, MCSubtargetInfo &STI,
    323                          MCInstrInfo &MCII, MCTargetOptions &MCOptions) {
    324   std::unique_ptr<MCAsmParser> Parser(
    325       createMCAsmParser(SrcMgr, Ctx, Str, MAI));
    326   std::unique_ptr<MCTargetAsmParser> TAP(
    327       TheTarget->createMCAsmParser(STI, *Parser, MCII, MCOptions));
    328 
    329   if (!TAP) {
    330     errs() << ProgName
    331            << ": error: this target does not support assembly parsing.\n";
    332     return 1;
    333   }
    334 
    335   Parser->setShowParsedOperands(ShowInstOperands);
    336   Parser->setTargetParser(*TAP.get());
    337 
    338   int Res = Parser->Run(NoInitialTextSection);
    339 
    340   return Res;
    341 }
    342 
    343 int main(int argc, char **argv) {
    344   // Print a stack trace if we signal out.
    345   sys::PrintStackTraceOnErrorSignal();
    346   PrettyStackTraceProgram X(argc, argv);
    347   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    348 
    349   // Initialize targets and assembly printers/parsers.
    350   llvm::InitializeAllTargetInfos();
    351   llvm::InitializeAllTargetMCs();
    352   llvm::InitializeAllAsmParsers();
    353   llvm::InitializeAllDisassemblers();
    354 
    355   // Register the target printer for --version.
    356   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
    357 
    358   cl::ParseCommandLineOptions(argc, argv, "llvm machine code playground\n");
    359   MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
    360   TripleName = Triple::normalize(TripleName);
    361   setDwarfDebugFlags(argc, argv);
    362 
    363   setDwarfDebugProducer();
    364 
    365   const char *ProgName = argv[0];
    366   const Target *TheTarget = GetTarget(ProgName);
    367   if (!TheTarget)
    368     return 1;
    369 
    370   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
    371       MemoryBuffer::getFileOrSTDIN(InputFilename);
    372   if (std::error_code EC = BufferPtr.getError()) {
    373     errs() << ProgName << ": " << EC.message() << '\n';
    374     return 1;
    375   }
    376   MemoryBuffer *Buffer = BufferPtr->release();
    377 
    378   SourceMgr SrcMgr;
    379 
    380   // Tell SrcMgr about this buffer, which is what the parser will pick up.
    381   SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
    382 
    383   // Record the location of the include directories so that the lexer can find
    384   // it later.
    385   SrcMgr.setIncludeDirs(IncludeDirs);
    386 
    387   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
    388   assert(MRI && "Unable to create target register info!");
    389 
    390   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
    391   assert(MAI && "Unable to create target asm info!");
    392 
    393   if (CompressDebugSections) {
    394     if (!zlib::isAvailable()) {
    395       errs() << ProgName
    396              << ": build tools with zlib to enable -compress-debug-sections";
    397       return 1;
    398     }
    399     MAI->setCompressDebugSections(true);
    400   }
    401 
    402   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
    403   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
    404   MCObjectFileInfo MOFI;
    405   MCContext Ctx(MAI.get(), MRI.get(), &MOFI, &SrcMgr);
    406   MOFI.InitMCObjectFileInfo(TripleName, RelocModel, CMModel, Ctx);
    407 
    408   if (SaveTempLabels)
    409     Ctx.setAllowTemporaryLabels(false);
    410 
    411   Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
    412   // Default to 4 for dwarf version.
    413   unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4;
    414   if (DwarfVersion < 2 || DwarfVersion > 4) {
    415     errs() << ProgName << ": Dwarf version " << DwarfVersion
    416            << " is not supported." << '\n';
    417     return 1;
    418   }
    419   Ctx.setDwarfVersion(DwarfVersion);
    420   if (!DwarfDebugFlags.empty())
    421     Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
    422   if (!DwarfDebugProducer.empty())
    423     Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer));
    424   if (!DebugCompilationDir.empty())
    425     Ctx.setCompilationDir(DebugCompilationDir);
    426   if (!MainFileName.empty())
    427     Ctx.setMainFileName(MainFileName);
    428 
    429   // Package up features to be passed to target/subtarget
    430   std::string FeaturesStr;
    431   if (MAttrs.size()) {
    432     SubtargetFeatures Features;
    433     for (unsigned i = 0; i != MAttrs.size(); ++i)
    434       Features.AddFeature(MAttrs[i]);
    435     FeaturesStr = Features.getString();
    436   }
    437 
    438   std::unique_ptr<tool_output_file> Out(GetOutputStream());
    439   if (!Out)
    440     return 1;
    441 
    442   formatted_raw_ostream FOS(Out->os());
    443   std::unique_ptr<MCStreamer> Str;
    444 
    445   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
    446   std::unique_ptr<MCSubtargetInfo> STI(
    447       TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
    448 
    449   MCInstPrinter *IP = nullptr;
    450   if (FileType == OFT_AssemblyFile) {
    451     IP =
    452       TheTarget->createMCInstPrinter(OutputAsmVariant, *MAI, *MCII, *MRI, *STI);
    453 
    454     // Set the display preference for hex vs. decimal immediates.
    455     IP->setPrintImmHex(PrintImmHex);
    456 
    457     // Set up the AsmStreamer.
    458     MCCodeEmitter *CE = nullptr;
    459     MCAsmBackend *MAB = nullptr;
    460     if (ShowEncoding) {
    461       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, *STI, Ctx);
    462       MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU);
    463     }
    464     Str.reset(TheTarget->createAsmStreamer(Ctx, FOS, /*asmverbose*/ true,
    465                                            /*useDwarfDirectory*/ true, IP, CE,
    466                                            MAB, ShowInst));
    467 
    468   } else if (FileType == OFT_Null) {
    469     Str.reset(createNullStreamer(Ctx));
    470   } else {
    471     assert(FileType == OFT_ObjectFile && "Invalid file type!");
    472     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, *STI, Ctx);
    473     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU);
    474     Str.reset(TheTarget->createMCObjectStreamer(TripleName, Ctx, *MAB,
    475                                                 FOS, CE, *STI, RelaxAll,
    476                                                 NoExecStack));
    477   }
    478 
    479   int Res = 1;
    480   bool disassemble = false;
    481   switch (Action) {
    482   case AC_AsLex:
    483     Res = AsLexInput(SrcMgr, *MAI, Out.get());
    484     break;
    485   case AC_Assemble:
    486     Res = AssembleInput(ProgName, TheTarget, SrcMgr, Ctx, *Str, *MAI, *STI,
    487                         *MCII, MCOptions);
    488     break;
    489   case AC_MDisassemble:
    490     assert(IP && "Expected assembly output");
    491     IP->setUseMarkup(1);
    492     disassemble = true;
    493     break;
    494   case AC_Disassemble:
    495     disassemble = true;
    496     break;
    497   }
    498   if (disassemble)
    499     Res = Disassembler::disassemble(*TheTarget, TripleName, *STI, *Str,
    500                                     *Buffer, SrcMgr, Out->os());
    501 
    502   // Keep output if no errors.
    503   if (Res == 0) Out->keep();
    504   return Res;
    505 }
    506