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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/Arg.h"
     18 #include "clang/Driver/ArgList.h"
     19 #include "clang/Driver/CC1AsOptions.h"
     20 #include "clang/Driver/DriverDiagnostic.h"
     21 #include "clang/Driver/OptTable.h"
     22 #include "clang/Driver/Options.h"
     23 #include "clang/Frontend/FrontendDiagnostic.h"
     24 #include "clang/Frontend/TextDiagnosticPrinter.h"
     25 #include "llvm/ADT/OwningPtr.h"
     26 #include "llvm/ADT/StringSwitch.h"
     27 #include "llvm/ADT/Triple.h"
     28 #include "llvm/IR/DataLayout.h"
     29 #include "llvm/MC/MCAsmBackend.h"
     30 #include "llvm/MC/MCAsmInfo.h"
     31 #include "llvm/MC/MCCodeEmitter.h"
     32 #include "llvm/MC/MCContext.h"
     33 #include "llvm/MC/MCInstrInfo.h"
     34 #include "llvm/MC/MCObjectFileInfo.h"
     35 #include "llvm/MC/MCParser/MCAsmParser.h"
     36 #include "llvm/MC/MCRegisterInfo.h"
     37 #include "llvm/MC/MCStreamer.h"
     38 #include "llvm/MC/MCSubtargetInfo.h"
     39 #include "llvm/MC/MCTargetAsmParser.h"
     40 #include "llvm/Support/CommandLine.h"
     41 #include "llvm/Support/ErrorHandling.h"
     42 #include "llvm/Support/FormattedStream.h"
     43 #include "llvm/Support/Host.h"
     44 #include "llvm/Support/ManagedStatic.h"
     45 #include "llvm/Support/MemoryBuffer.h"
     46 #include "llvm/Support/Path.h"
     47 #include "llvm/Support/PrettyStackTrace.h"
     48 #include "llvm/Support/Signals.h"
     49 #include "llvm/Support/SourceMgr.h"
     50 #include "llvm/Support/TargetRegistry.h"
     51 #include "llvm/Support/TargetSelect.h"
     52 #include "llvm/Support/Timer.h"
     53 #include "llvm/Support/raw_ostream.h"
     54 #include "llvm/Support/system_error.h"
     55 using namespace clang;
     56 using namespace clang::driver;
     57 using namespace llvm;
     58 
     59 namespace {
     60 
     61 /// \brief Helper class for representing a single invocation of the assembler.
     62 struct AssemblerInvocation {
     63   /// @name Target Options
     64   /// @{
     65 
     66   /// The name of the target triple to assemble for.
     67   std::string Triple;
     68 
     69   /// If given, the name of the target CPU to determine which instructions
     70   /// are legal.
     71   std::string CPU;
     72 
     73   /// The list of target specific features to enable or disable -- this should
     74   /// be a list of strings starting with '+' or '-'.
     75   std::vector<std::string> Features;
     76 
     77   /// @}
     78   /// @name Language Options
     79   /// @{
     80 
     81   std::vector<std::string> IncludePaths;
     82   unsigned NoInitialTextSection : 1;
     83   unsigned SaveTemporaryLabels : 1;
     84   unsigned GenDwarfForAssembly : 1;
     85   std::string DwarfDebugFlags;
     86   std::string DwarfDebugProducer;
     87   std::string DebugCompilationDir;
     88   std::string MainFileName;
     89 
     90   /// @}
     91   /// @name Frontend Options
     92   /// @{
     93 
     94   std::string InputFile;
     95   std::vector<std::string> LLVMArgs;
     96   std::string OutputPath;
     97   enum FileType {
     98     FT_Asm,  ///< Assembly (.s) output, transliterate mode.
     99     FT_Null, ///< No output, for timing purposes.
    100     FT_Obj   ///< Object file output.
    101   };
    102   FileType OutputType;
    103   unsigned ShowHelp : 1;
    104   unsigned ShowVersion : 1;
    105 
    106   /// @}
    107   /// @name Transliterate Options
    108   /// @{
    109 
    110   unsigned OutputAsmVariant;
    111   unsigned ShowEncoding : 1;
    112   unsigned ShowInst : 1;
    113 
    114   /// @}
    115   /// @name Assembler Options
    116   /// @{
    117 
    118   unsigned RelaxAll : 1;
    119   unsigned NoExecStack : 1;
    120 
    121   /// @}
    122 
    123 public:
    124   AssemblerInvocation() {
    125     Triple = "";
    126     NoInitialTextSection = 0;
    127     InputFile = "-";
    128     OutputPath = "-";
    129     OutputType = FT_Asm;
    130     OutputAsmVariant = 0;
    131     ShowInst = 0;
    132     ShowEncoding = 0;
    133     RelaxAll = 0;
    134     NoExecStack = 0;
    135   }
    136 
    137   static bool CreateFromArgs(AssemblerInvocation &Res, const char **ArgBegin,
    138                              const char **ArgEnd, DiagnosticsEngine &Diags);
    139 };
    140 
    141 }
    142 
    143 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
    144                                          const char **ArgBegin,
    145                                          const char **ArgEnd,
    146                                          DiagnosticsEngine &Diags) {
    147   using namespace clang::driver::cc1asoptions;
    148   bool Success = true;
    149 
    150   // Parse the arguments.
    151   OwningPtr<OptTable> OptTbl(createCC1AsOptTable());
    152   unsigned MissingArgIndex, MissingArgCount;
    153   OwningPtr<InputArgList> Args(
    154     OptTbl->ParseArgs(ArgBegin, ArgEnd,MissingArgIndex, MissingArgCount));
    155 
    156   // Check for missing argument error.
    157   if (MissingArgCount) {
    158     Diags.Report(diag::err_drv_missing_argument)
    159       << Args->getArgString(MissingArgIndex) << MissingArgCount;
    160     Success = false;
    161   }
    162 
    163   // Issue errors on unknown arguments.
    164   for (arg_iterator it = Args->filtered_begin(cc1asoptions::OPT_UNKNOWN),
    165          ie = Args->filtered_end(); it != ie; ++it) {
    166     Diags.Report(diag::err_drv_unknown_argument) << (*it) ->getAsString(*Args);
    167     Success = false;
    168   }
    169 
    170   // Construct the invocation.
    171 
    172   // Target Options
    173   Opts.Triple = llvm::Triple::normalize(Args->getLastArgValue(OPT_triple));
    174   Opts.CPU = Args->getLastArgValue(OPT_target_cpu);
    175   Opts.Features = Args->getAllArgValues(OPT_target_feature);
    176 
    177   // Use the default target triple if unspecified.
    178   if (Opts.Triple.empty())
    179     Opts.Triple = llvm::sys::getDefaultTargetTriple();
    180 
    181   // Language Options
    182   Opts.IncludePaths = Args->getAllArgValues(OPT_I);
    183   Opts.NoInitialTextSection = Args->hasArg(OPT_n);
    184   Opts.SaveTemporaryLabels = Args->hasArg(OPT_L);
    185   Opts.GenDwarfForAssembly = Args->hasArg(OPT_g);
    186   Opts.DwarfDebugFlags = Args->getLastArgValue(OPT_dwarf_debug_flags);
    187   Opts.DwarfDebugProducer = Args->getLastArgValue(OPT_dwarf_debug_producer);
    188   Opts.DebugCompilationDir = Args->getLastArgValue(OPT_fdebug_compilation_dir);
    189   Opts.MainFileName = Args->getLastArgValue(OPT_main_file_name);
    190 
    191   // Frontend Options
    192   if (Args->hasArg(OPT_INPUT)) {
    193     bool First = true;
    194     for (arg_iterator it = Args->filtered_begin(OPT_INPUT),
    195            ie = Args->filtered_end(); it != ie; ++it, First=false) {
    196       const Arg *A = it;
    197       if (First)
    198         Opts.InputFile = A->getValue();
    199       else {
    200         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(*Args);
    201         Success = false;
    202       }
    203     }
    204   }
    205   Opts.LLVMArgs = Args->getAllArgValues(OPT_mllvm);
    206   if (Args->hasArg(OPT_fatal_warnings))
    207     Opts.LLVMArgs.push_back("-fatal-assembler-warnings");
    208   Opts.OutputPath = Args->getLastArgValue(OPT_o);
    209   if (Arg *A = Args->getLastArg(OPT_filetype)) {
    210     StringRef Name = A->getValue();
    211     unsigned OutputType = StringSwitch<unsigned>(Name)
    212       .Case("asm", FT_Asm)
    213       .Case("null", FT_Null)
    214       .Case("obj", FT_Obj)
    215       .Default(~0U);
    216     if (OutputType == ~0U) {
    217       Diags.Report(diag::err_drv_invalid_value)
    218         << A->getAsString(*Args) << Name;
    219       Success = false;
    220     } else
    221       Opts.OutputType = FileType(OutputType);
    222   }
    223   Opts.ShowHelp = Args->hasArg(OPT_help);
    224   Opts.ShowVersion = Args->hasArg(OPT_version);
    225 
    226   // Transliterate Options
    227   Opts.OutputAsmVariant = Args->getLastArgIntValue(OPT_output_asm_variant,
    228                                                    0, Diags);
    229   Opts.ShowEncoding = Args->hasArg(OPT_show_encoding);
    230   Opts.ShowInst = Args->hasArg(OPT_show_inst);
    231 
    232   // Assemble Options
    233   Opts.RelaxAll = Args->hasArg(OPT_relax_all);
    234   Opts.NoExecStack =  Args->hasArg(OPT_no_exec_stack);
    235 
    236   return Success;
    237 }
    238 
    239 static formatted_raw_ostream *GetOutputStream(AssemblerInvocation &Opts,
    240                                               DiagnosticsEngine &Diags,
    241                                               bool Binary) {
    242   if (Opts.OutputPath.empty())
    243     Opts.OutputPath = "-";
    244 
    245   // Make sure that the Out file gets unlinked from the disk if we get a
    246   // SIGINT.
    247   if (Opts.OutputPath != "-")
    248     sys::RemoveFileOnSignal(sys::Path(Opts.OutputPath));
    249 
    250   std::string Error;
    251   raw_fd_ostream *Out =
    252     new raw_fd_ostream(Opts.OutputPath.c_str(), Error,
    253                        (Binary ? raw_fd_ostream::F_Binary : 0));
    254   if (!Error.empty()) {
    255     Diags.Report(diag::err_fe_unable_to_open_output)
    256       << Opts.OutputPath << Error;
    257     return 0;
    258   }
    259 
    260   return new formatted_raw_ostream(*Out, formatted_raw_ostream::DELETE_STREAM);
    261 }
    262 
    263 static bool ExecuteAssembler(AssemblerInvocation &Opts,
    264                              DiagnosticsEngine &Diags) {
    265   // Get the target specific parser.
    266   std::string Error;
    267   const Target *TheTarget(TargetRegistry::lookupTarget(Opts.Triple, Error));
    268   if (!TheTarget) {
    269     Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    270     return false;
    271   }
    272 
    273   OwningPtr<MemoryBuffer> BufferPtr;
    274   if (error_code ec = MemoryBuffer::getFileOrSTDIN(Opts.InputFile, BufferPtr)) {
    275     Error = ec.message();
    276     Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
    277     return false;
    278   }
    279   MemoryBuffer *Buffer = BufferPtr.take();
    280 
    281   SourceMgr SrcMgr;
    282 
    283   // Tell SrcMgr about this buffer, which is what the parser will pick up.
    284   SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
    285 
    286   // Record the location of the include directories so that the lexer can find
    287   // it later.
    288   SrcMgr.setIncludeDirs(Opts.IncludePaths);
    289 
    290   OwningPtr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(Opts.Triple));
    291   assert(MAI && "Unable to create target asm info!");
    292 
    293   OwningPtr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
    294   assert(MRI && "Unable to create target register info!");
    295 
    296   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
    297   formatted_raw_ostream *Out = GetOutputStream(Opts, Diags, IsBinary);
    298   if (!Out)
    299     return false;
    300 
    301   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
    302   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
    303   OwningPtr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
    304   MCContext Ctx(*MAI, *MRI, MOFI.get(), &SrcMgr);
    305   // FIXME: Assembler behavior can change with -static.
    306   MOFI->InitMCObjectFileInfo(Opts.Triple,
    307                              Reloc::Default, CodeModel::Default, Ctx);
    308   if (Opts.SaveTemporaryLabels)
    309     Ctx.setAllowTemporaryLabels(false);
    310   if (Opts.GenDwarfForAssembly)
    311     Ctx.setGenDwarfForAssembly(true);
    312   if (!Opts.DwarfDebugFlags.empty())
    313     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
    314   if (!Opts.DwarfDebugProducer.empty())
    315     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
    316   if (!Opts.DebugCompilationDir.empty())
    317     Ctx.setCompilationDir(Opts.DebugCompilationDir);
    318   if (!Opts.MainFileName.empty())
    319     Ctx.setMainFileName(StringRef(Opts.MainFileName));
    320 
    321   // Build up the feature string from the target feature list.
    322   std::string FS;
    323   if (!Opts.Features.empty()) {
    324     FS = Opts.Features[0];
    325     for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
    326       FS += "," + Opts.Features[i];
    327   }
    328 
    329   OwningPtr<MCStreamer> Str;
    330 
    331   OwningPtr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
    332   OwningPtr<MCSubtargetInfo>
    333     STI(TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
    334 
    335   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
    336   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
    337     MCInstPrinter *IP =
    338       TheTarget->createMCInstPrinter(Opts.OutputAsmVariant, *MAI, *MCII, *MRI,
    339                                      *STI);
    340     MCCodeEmitter *CE = 0;
    341     MCAsmBackend *MAB = 0;
    342     if (Opts.ShowEncoding) {
    343       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, *STI, Ctx);
    344       MAB = TheTarget->createMCAsmBackend(Opts.Triple, Opts.CPU);
    345     }
    346     Str.reset(TheTarget->createAsmStreamer(Ctx, *Out, /*asmverbose*/true,
    347                                            /*useLoc*/ true,
    348                                            /*useCFI*/ true,
    349                                            /*useDwarfDirectory*/ true,
    350                                            IP, CE, MAB,
    351                                            Opts.ShowInst));
    352   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
    353     Str.reset(createNullStreamer(Ctx));
    354   } else {
    355     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
    356            "Invalid file type!");
    357     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, *STI, Ctx);
    358     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(Opts.Triple, Opts.CPU);
    359     Str.reset(TheTarget->createMCObjectStreamer(Opts.Triple, Ctx, *MAB, *Out,
    360                                                 CE, Opts.RelaxAll,
    361                                                 Opts.NoExecStack));
    362     Str.get()->InitSections();
    363   }
    364 
    365   OwningPtr<MCAsmParser> Parser(createMCAsmParser(SrcMgr, Ctx,
    366                                                   *Str.get(), *MAI));
    367   OwningPtr<MCTargetAsmParser> TAP(TheTarget->createMCAsmParser(*STI, *Parser));
    368   if (!TAP) {
    369     Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    370     return false;
    371   }
    372 
    373   Parser->setTargetParser(*TAP.get());
    374 
    375   bool Success = !Parser->Run(Opts.NoInitialTextSection);
    376 
    377   // Close the output.
    378   delete Out;
    379 
    380   // Delete output on errors.
    381   if (!Success && Opts.OutputPath != "-")
    382     sys::Path(Opts.OutputPath).eraseFromDisk();
    383 
    384   return Success;
    385 }
    386 
    387 static void LLVMErrorHandler(void *UserData, const std::string &Message) {
    388   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
    389 
    390   Diags.Report(diag::err_fe_error_backend) << Message;
    391 
    392   // We cannot recover from llvm errors.
    393   exit(1);
    394 }
    395 
    396 int cc1as_main(const char **ArgBegin, const char **ArgEnd,
    397                const char *Argv0, void *MainAddr) {
    398   // Print a stack trace if we signal out.
    399   sys::PrintStackTraceOnErrorSignal();
    400   PrettyStackTraceProgram X(ArgEnd - ArgBegin, ArgBegin);
    401   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    402 
    403   // Initialize targets and assembly printers/parsers.
    404   InitializeAllTargetInfos();
    405   InitializeAllTargetMCs();
    406   InitializeAllAsmParsers();
    407 
    408   // Construct our diagnostic client.
    409   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
    410   TextDiagnosticPrinter *DiagClient
    411     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
    412   DiagClient->setPrefix("clang -cc1as");
    413   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
    414   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
    415 
    416   // Set an error handler, so that any LLVM backend diagnostics go through our
    417   // error handler.
    418   ScopedFatalErrorHandler FatalErrorHandler
    419     (LLVMErrorHandler, static_cast<void*>(&Diags));
    420 
    421   // Parse the arguments.
    422   AssemblerInvocation Asm;
    423   if (!AssemblerInvocation::CreateFromArgs(Asm, ArgBegin, ArgEnd, Diags))
    424     return 1;
    425 
    426   // Honor -help.
    427   if (Asm.ShowHelp) {
    428     OwningPtr<driver::OptTable> Opts(driver::createCC1AsOptTable());
    429     Opts->PrintHelp(llvm::outs(), "clang -cc1as", "Clang Integrated Assembler");
    430     return 0;
    431   }
    432 
    433   // Honor -version.
    434   //
    435   // FIXME: Use a better -version message?
    436   if (Asm.ShowVersion) {
    437     llvm::cl::PrintVersionMessage();
    438     return 0;
    439   }
    440 
    441   // Honor -mllvm.
    442   //
    443   // FIXME: Remove this, one day.
    444   if (!Asm.LLVMArgs.empty()) {
    445     unsigned NumArgs = Asm.LLVMArgs.size();
    446     const char **Args = new const char*[NumArgs + 2];
    447     Args[0] = "clang (LLVM option parsing)";
    448     for (unsigned i = 0; i != NumArgs; ++i)
    449       Args[i + 1] = Asm.LLVMArgs[i].c_str();
    450     Args[NumArgs + 1] = 0;
    451     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args);
    452   }
    453 
    454   // Execute the invocation, unless there were parsing errors.
    455   bool Success = false;
    456   if (!Diags.hasErrorOccurred())
    457     Success = ExecuteAssembler(Asm, Diags);
    458 
    459   // If any timers were active but haven't been destroyed yet, print their
    460   // results now.
    461   TimerGroup::printAll(errs());
    462 
    463   return !Success;
    464 }
    465