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      1 //===-- cc1as_main.cpp - Clang Assembler  ---------------------------------===//
      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 is the entry point to the clang -cc1as functionality, which implements
     11 // the direct interface to the LLVM MC based assembler.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "clang/Basic/Diagnostic.h"
     16 #include "clang/Basic/DiagnosticOptions.h"
     17 #include "clang/Driver/DriverDiagnostic.h"
     18 #include "clang/Driver/Options.h"
     19 #include "clang/Frontend/FrontendDiagnostic.h"
     20 #include "clang/Frontend/TextDiagnosticPrinter.h"
     21 #include "clang/Frontend/Utils.h"
     22 #include "llvm/ADT/STLExtras.h"
     23 #include "llvm/ADT/StringSwitch.h"
     24 #include "llvm/ADT/Triple.h"
     25 #include "llvm/IR/DataLayout.h"
     26 #include "llvm/MC/MCAsmBackend.h"
     27 #include "llvm/MC/MCAsmInfo.h"
     28 #include "llvm/MC/MCCodeEmitter.h"
     29 #include "llvm/MC/MCContext.h"
     30 #include "llvm/MC/MCInstrInfo.h"
     31 #include "llvm/MC/MCObjectFileInfo.h"
     32 #include "llvm/MC/MCParser/MCAsmParser.h"
     33 #include "llvm/MC/MCRegisterInfo.h"
     34 #include "llvm/MC/MCStreamer.h"
     35 #include "llvm/MC/MCSubtargetInfo.h"
     36 #include "llvm/MC/MCTargetAsmParser.h"
     37 #include "llvm/MC/MCTargetOptions.h"
     38 #include "llvm/Option/Arg.h"
     39 #include "llvm/Option/ArgList.h"
     40 #include "llvm/Option/OptTable.h"
     41 #include "llvm/Support/CommandLine.h"
     42 #include "llvm/Support/ErrorHandling.h"
     43 #include "llvm/Support/FileSystem.h"
     44 #include "llvm/Support/FormattedStream.h"
     45 #include "llvm/Support/Host.h"
     46 #include "llvm/Support/ManagedStatic.h"
     47 #include "llvm/Support/MemoryBuffer.h"
     48 #include "llvm/Support/Path.h"
     49 #include "llvm/Support/PrettyStackTrace.h"
     50 #include "llvm/Support/Signals.h"
     51 #include "llvm/Support/SourceMgr.h"
     52 #include "llvm/Support/TargetRegistry.h"
     53 #include "llvm/Support/TargetSelect.h"
     54 #include "llvm/Support/Timer.h"
     55 #include "llvm/Support/raw_ostream.h"
     56 #include <memory>
     57 #include <system_error>
     58 using namespace clang;
     59 using namespace clang::driver;
     60 using namespace clang::driver::options;
     61 using namespace llvm;
     62 using namespace llvm::opt;
     63 
     64 namespace {
     65 
     66 /// \brief Helper class for representing a single invocation of the assembler.
     67 struct AssemblerInvocation {
     68   /// @name Target Options
     69   /// @{
     70 
     71   /// The name of the target triple to assemble for.
     72   std::string Triple;
     73 
     74   /// If given, the name of the target CPU to determine which instructions
     75   /// are legal.
     76   std::string CPU;
     77 
     78   /// The list of target specific features to enable or disable -- this should
     79   /// be a list of strings starting with '+' or '-'.
     80   std::vector<std::string> Features;
     81 
     82   /// @}
     83   /// @name Language Options
     84   /// @{
     85 
     86   std::vector<std::string> IncludePaths;
     87   unsigned NoInitialTextSection : 1;
     88   unsigned SaveTemporaryLabels : 1;
     89   unsigned GenDwarfForAssembly : 1;
     90   unsigned CompressDebugSections : 1;
     91   unsigned DwarfVersion;
     92   std::string DwarfDebugFlags;
     93   std::string DwarfDebugProducer;
     94   std::string DebugCompilationDir;
     95   std::string MainFileName;
     96 
     97   /// @}
     98   /// @name Frontend Options
     99   /// @{
    100 
    101   std::string InputFile;
    102   std::vector<std::string> LLVMArgs;
    103   std::string OutputPath;
    104   enum FileType {
    105     FT_Asm,  ///< Assembly (.s) output, transliterate mode.
    106     FT_Null, ///< No output, for timing purposes.
    107     FT_Obj   ///< Object file output.
    108   };
    109   FileType OutputType;
    110   unsigned ShowHelp : 1;
    111   unsigned ShowVersion : 1;
    112 
    113   /// @}
    114   /// @name Transliterate Options
    115   /// @{
    116 
    117   unsigned OutputAsmVariant;
    118   unsigned ShowEncoding : 1;
    119   unsigned ShowInst : 1;
    120 
    121   /// @}
    122   /// @name Assembler Options
    123   /// @{
    124 
    125   unsigned RelaxAll : 1;
    126   unsigned NoExecStack : 1;
    127   unsigned FatalWarnings : 1;
    128   unsigned IncrementalLinkerCompatible : 1;
    129 
    130   /// The name of the relocation model to use.
    131   std::string RelocationModel;
    132 
    133   /// @}
    134 
    135 public:
    136   AssemblerInvocation() {
    137     Triple = "";
    138     NoInitialTextSection = 0;
    139     InputFile = "-";
    140     OutputPath = "-";
    141     OutputType = FT_Asm;
    142     OutputAsmVariant = 0;
    143     ShowInst = 0;
    144     ShowEncoding = 0;
    145     RelaxAll = 0;
    146     NoExecStack = 0;
    147     FatalWarnings = 0;
    148     IncrementalLinkerCompatible = 0;
    149     DwarfVersion = 0;
    150   }
    151 
    152   static bool CreateFromArgs(AssemblerInvocation &Res,
    153                              ArrayRef<const char *> Argv,
    154                              DiagnosticsEngine &Diags);
    155 };
    156 
    157 }
    158 
    159 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
    160                                          ArrayRef<const char *> Argv,
    161                                          DiagnosticsEngine &Diags) {
    162   bool Success = true;
    163 
    164   // Parse the arguments.
    165   std::unique_ptr<OptTable> OptTbl(createDriverOptTable());
    166 
    167   const unsigned IncludedFlagsBitmask = options::CC1AsOption;
    168   unsigned MissingArgIndex, MissingArgCount;
    169   InputArgList Args = OptTbl->ParseArgs(Argv, MissingArgIndex, MissingArgCount,
    170                                         IncludedFlagsBitmask);
    171 
    172   // Check for missing argument error.
    173   if (MissingArgCount) {
    174     Diags.Report(diag::err_drv_missing_argument)
    175         << Args.getArgString(MissingArgIndex) << MissingArgCount;
    176     Success = false;
    177   }
    178 
    179   // Issue errors on unknown arguments.
    180   for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {
    181     Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
    182     Success = false;
    183   }
    184 
    185   // Construct the invocation.
    186 
    187   // Target Options
    188   Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
    189   Opts.CPU = Args.getLastArgValue(OPT_target_cpu);
    190   Opts.Features = Args.getAllArgValues(OPT_target_feature);
    191 
    192   // Use the default target triple if unspecified.
    193   if (Opts.Triple.empty())
    194     Opts.Triple = llvm::sys::getDefaultTargetTriple();
    195 
    196   // Language Options
    197   Opts.IncludePaths = Args.getAllArgValues(OPT_I);
    198   Opts.NoInitialTextSection = Args.hasArg(OPT_n);
    199   Opts.SaveTemporaryLabels = Args.hasArg(OPT_msave_temp_labels);
    200   // Any DebugInfoKind implies GenDwarfForAssembly.
    201   Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);
    202   Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
    203   Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 0, Diags);
    204   Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
    205   Opts.DwarfDebugProducer = Args.getLastArgValue(OPT_dwarf_debug_producer);
    206   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
    207   Opts.MainFileName = Args.getLastArgValue(OPT_main_file_name);
    208 
    209   // Frontend Options
    210   if (Args.hasArg(OPT_INPUT)) {
    211     bool First = true;
    212     for (arg_iterator it = Args.filtered_begin(OPT_INPUT),
    213                       ie = Args.filtered_end();
    214          it != ie; ++it, First = false) {
    215       const Arg *A = it;
    216       if (First)
    217         Opts.InputFile = A->getValue();
    218       else {
    219         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
    220         Success = false;
    221       }
    222     }
    223   }
    224   Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
    225   Opts.OutputPath = Args.getLastArgValue(OPT_o);
    226   if (Arg *A = Args.getLastArg(OPT_filetype)) {
    227     StringRef Name = A->getValue();
    228     unsigned OutputType = StringSwitch<unsigned>(Name)
    229       .Case("asm", FT_Asm)
    230       .Case("null", FT_Null)
    231       .Case("obj", FT_Obj)
    232       .Default(~0U);
    233     if (OutputType == ~0U) {
    234       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
    235       Success = false;
    236     } else
    237       Opts.OutputType = FileType(OutputType);
    238   }
    239   Opts.ShowHelp = Args.hasArg(OPT_help);
    240   Opts.ShowVersion = Args.hasArg(OPT_version);
    241 
    242   // Transliterate Options
    243   Opts.OutputAsmVariant =
    244       getLastArgIntValue(Args, OPT_output_asm_variant, 0, Diags);
    245   Opts.ShowEncoding = Args.hasArg(OPT_show_encoding);
    246   Opts.ShowInst = Args.hasArg(OPT_show_inst);
    247 
    248   // Assemble Options
    249   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
    250   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
    251   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
    252   Opts.RelocationModel = Args.getLastArgValue(OPT_mrelocation_model, "pic");
    253   Opts.IncrementalLinkerCompatible =
    254       Args.hasArg(OPT_mincremental_linker_compatible);
    255 
    256   return Success;
    257 }
    258 
    259 static std::unique_ptr<raw_fd_ostream>
    260 getOutputStream(AssemblerInvocation &Opts, DiagnosticsEngine &Diags,
    261                 bool Binary) {
    262   if (Opts.OutputPath.empty())
    263     Opts.OutputPath = "-";
    264 
    265   // Make sure that the Out file gets unlinked from the disk if we get a
    266   // SIGINT.
    267   if (Opts.OutputPath != "-")
    268     sys::RemoveFileOnSignal(Opts.OutputPath);
    269 
    270   std::error_code EC;
    271   auto Out = llvm::make_unique<raw_fd_ostream>(
    272       Opts.OutputPath, EC, (Binary ? sys::fs::F_None : sys::fs::F_Text));
    273   if (EC) {
    274     Diags.Report(diag::err_fe_unable_to_open_output) << Opts.OutputPath
    275                                                      << EC.message();
    276     return nullptr;
    277   }
    278 
    279   return Out;
    280 }
    281 
    282 static bool ExecuteAssembler(AssemblerInvocation &Opts,
    283                              DiagnosticsEngine &Diags) {
    284   // Get the target specific parser.
    285   std::string Error;
    286   const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
    287   if (!TheTarget)
    288     return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    289 
    290   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
    291       MemoryBuffer::getFileOrSTDIN(Opts.InputFile);
    292 
    293   if (std::error_code EC = Buffer.getError()) {
    294     Error = EC.message();
    295     return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
    296   }
    297 
    298   SourceMgr SrcMgr;
    299 
    300   // Tell SrcMgr about this buffer, which is what the parser will pick up.
    301   SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
    302 
    303   // Record the location of the include directories so that the lexer can find
    304   // it later.
    305   SrcMgr.setIncludeDirs(Opts.IncludePaths);
    306 
    307   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
    308   assert(MRI && "Unable to create target register info!");
    309 
    310   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, Opts.Triple));
    311   assert(MAI && "Unable to create target asm info!");
    312 
    313   // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
    314   // may be created with a combination of default and explicit settings.
    315   if (Opts.CompressDebugSections)
    316     MAI->setCompressDebugSections(true);
    317 
    318   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
    319   std::unique_ptr<raw_fd_ostream> FDOS = getOutputStream(Opts, Diags, IsBinary);
    320   if (!FDOS)
    321     return true;
    322 
    323   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
    324   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
    325   std::unique_ptr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
    326 
    327   MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &SrcMgr);
    328 
    329   llvm::Reloc::Model RM = llvm::Reloc::Default;
    330   if (Opts.RelocationModel == "static") {
    331     RM = llvm::Reloc::Static;
    332   } else if (Opts.RelocationModel == "pic") {
    333     RM = llvm::Reloc::PIC_;
    334   } else {
    335     assert(Opts.RelocationModel == "dynamic-no-pic" &&
    336            "Invalid PIC model!");
    337     RM = llvm::Reloc::DynamicNoPIC;
    338   }
    339 
    340   MOFI->InitMCObjectFileInfo(Triple(Opts.Triple), RM,
    341                              CodeModel::Default, Ctx);
    342   if (Opts.SaveTemporaryLabels)
    343     Ctx.setAllowTemporaryLabels(false);
    344   if (Opts.GenDwarfForAssembly)
    345     Ctx.setGenDwarfForAssembly(true);
    346   if (!Opts.DwarfDebugFlags.empty())
    347     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
    348   if (!Opts.DwarfDebugProducer.empty())
    349     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
    350   if (!Opts.DebugCompilationDir.empty())
    351     Ctx.setCompilationDir(Opts.DebugCompilationDir);
    352   if (!Opts.MainFileName.empty())
    353     Ctx.setMainFileName(StringRef(Opts.MainFileName));
    354   Ctx.setDwarfVersion(Opts.DwarfVersion);
    355 
    356   // Build up the feature string from the target feature list.
    357   std::string FS;
    358   if (!Opts.Features.empty()) {
    359     FS = Opts.Features[0];
    360     for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
    361       FS += "," + Opts.Features[i];
    362   }
    363 
    364   std::unique_ptr<MCStreamer> Str;
    365 
    366   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
    367   std::unique_ptr<MCSubtargetInfo> STI(
    368       TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
    369 
    370   raw_pwrite_stream *Out = FDOS.get();
    371   std::unique_ptr<buffer_ostream> BOS;
    372 
    373   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
    374   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
    375     MCInstPrinter *IP = TheTarget->createMCInstPrinter(
    376         llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
    377     MCCodeEmitter *CE = nullptr;
    378     MCAsmBackend *MAB = nullptr;
    379     if (Opts.ShowEncoding) {
    380       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
    381       MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple, Opts.CPU);
    382     }
    383     auto FOut = llvm::make_unique<formatted_raw_ostream>(*Out);
    384     Str.reset(TheTarget->createAsmStreamer(
    385         Ctx, std::move(FOut), /*asmverbose*/ true,
    386         /*useDwarfDirectory*/ true, IP, CE, MAB, Opts.ShowInst));
    387   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
    388     Str.reset(createNullStreamer(Ctx));
    389   } else {
    390     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
    391            "Invalid file type!");
    392     if (!FDOS->supportsSeeking()) {
    393       BOS = make_unique<buffer_ostream>(*FDOS);
    394       Out = BOS.get();
    395     }
    396 
    397     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
    398     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple,
    399                                                       Opts.CPU);
    400     Triple T(Opts.Triple);
    401     Str.reset(TheTarget->createMCObjectStreamer(
    402         T, Ctx, *MAB, *Out, CE, *STI, Opts.RelaxAll,
    403         Opts.IncrementalLinkerCompatible,
    404         /*DWARFMustBeAtTheEnd*/ true));
    405     Str.get()->InitSections(Opts.NoExecStack);
    406   }
    407 
    408   bool Failed = false;
    409 
    410   std::unique_ptr<MCAsmParser> Parser(
    411       createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
    412 
    413   // FIXME: init MCTargetOptions from sanitizer flags here.
    414   MCTargetOptions Options;
    415   std::unique_ptr<MCTargetAsmParser> TAP(
    416       TheTarget->createMCAsmParser(*STI, *Parser, *MCII, Options));
    417   if (!TAP)
    418     Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    419 
    420   if (!Failed) {
    421     Parser->setTargetParser(*TAP.get());
    422     Failed = Parser->Run(Opts.NoInitialTextSection);
    423   }
    424 
    425   // Close Streamer first.
    426   // It might have a reference to the output stream.
    427   Str.reset();
    428   // Close the output stream early.
    429   BOS.reset();
    430   FDOS.reset();
    431 
    432   // Delete output file if there were errors.
    433   if (Failed && Opts.OutputPath != "-")
    434     sys::fs::remove(Opts.OutputPath);
    435 
    436   return Failed;
    437 }
    438 
    439 static void LLVMErrorHandler(void *UserData, const std::string &Message,
    440                              bool GenCrashDiag) {
    441   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
    442 
    443   Diags.Report(diag::err_fe_error_backend) << Message;
    444 
    445   // We cannot recover from llvm errors.
    446   exit(1);
    447 }
    448 
    449 int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
    450   // Print a stack trace if we signal out.
    451   sys::PrintStackTraceOnErrorSignal();
    452   PrettyStackTraceProgram X(Argv.size(), Argv.data());
    453   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    454 
    455   // Initialize targets and assembly printers/parsers.
    456   InitializeAllTargetInfos();
    457   InitializeAllTargetMCs();
    458   InitializeAllAsmParsers();
    459 
    460   // Construct our diagnostic client.
    461   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
    462   TextDiagnosticPrinter *DiagClient
    463     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
    464   DiagClient->setPrefix("clang -cc1as");
    465   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
    466   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
    467 
    468   // Set an error handler, so that any LLVM backend diagnostics go through our
    469   // error handler.
    470   ScopedFatalErrorHandler FatalErrorHandler
    471     (LLVMErrorHandler, static_cast<void*>(&Diags));
    472 
    473   // Parse the arguments.
    474   AssemblerInvocation Asm;
    475   if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
    476     return 1;
    477 
    478   if (Asm.ShowHelp) {
    479     std::unique_ptr<OptTable> Opts(driver::createDriverOptTable());
    480     Opts->PrintHelp(llvm::outs(), "clang -cc1as", "Clang Integrated Assembler",
    481                     /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0);
    482     return 0;
    483   }
    484 
    485   // Honor -version.
    486   //
    487   // FIXME: Use a better -version message?
    488   if (Asm.ShowVersion) {
    489     llvm::cl::PrintVersionMessage();
    490     return 0;
    491   }
    492 
    493   // Honor -mllvm.
    494   //
    495   // FIXME: Remove this, one day.
    496   if (!Asm.LLVMArgs.empty()) {
    497     unsigned NumArgs = Asm.LLVMArgs.size();
    498     const char **Args = new const char*[NumArgs + 2];
    499     Args[0] = "clang (LLVM option parsing)";
    500     for (unsigned i = 0; i != NumArgs; ++i)
    501       Args[i + 1] = Asm.LLVMArgs[i].c_str();
    502     Args[NumArgs + 1] = nullptr;
    503     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args);
    504   }
    505 
    506   // Execute the invocation, unless there were parsing errors.
    507   bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
    508 
    509   // If any timers were active but haven't been destroyed yet, print their
    510   // results now.
    511   TimerGroup::printAll(errs());
    512 
    513   return !!Failed;
    514 }
    515