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