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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/CC1AsOptions.h"
     18 #include "clang/Driver/DriverDiagnostic.h"
     19 #include "clang/Driver/Options.h"
     20 #include "clang/Frontend/FrontendDiagnostic.h"
     21 #include "clang/Frontend/TextDiagnosticPrinter.h"
     22 #include "clang/Frontend/Utils.h"
     23 #include "llvm/ADT/OwningPtr.h"
     24 #include "llvm/ADT/StringSwitch.h"
     25 #include "llvm/ADT/Triple.h"
     26 #include "llvm/IR/DataLayout.h"
     27 #include "llvm/MC/MCAsmBackend.h"
     28 #include "llvm/MC/MCAsmInfo.h"
     29 #include "llvm/MC/MCCodeEmitter.h"
     30 #include "llvm/MC/MCContext.h"
     31 #include "llvm/MC/MCInstrInfo.h"
     32 #include "llvm/MC/MCObjectFileInfo.h"
     33 #include "llvm/MC/MCParser/MCAsmParser.h"
     34 #include "llvm/MC/MCRegisterInfo.h"
     35 #include "llvm/MC/MCStreamer.h"
     36 #include "llvm/MC/MCSubtargetInfo.h"
     37 #include "llvm/MC/MCTargetAsmParser.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 "llvm/Support/system_error.h"
     57 using namespace clang;
     58 using namespace clang::driver;
     59 using namespace llvm;
     60 using namespace llvm::opt;
     61 
     62 namespace {
     63 
     64 /// \brief Helper class for representing a single invocation of the assembler.
     65 struct AssemblerInvocation {
     66   /// @name Target Options
     67   /// @{
     68 
     69   /// The name of the target triple to assemble for.
     70   std::string Triple;
     71 
     72   /// If given, the name of the target CPU to determine which instructions
     73   /// are legal.
     74   std::string CPU;
     75 
     76   /// The list of target specific features to enable or disable -- this should
     77   /// be a list of strings starting with '+' or '-'.
     78   std::vector<std::string> Features;
     79 
     80   /// @}
     81   /// @name Language Options
     82   /// @{
     83 
     84   std::vector<std::string> IncludePaths;
     85   unsigned NoInitialTextSection : 1;
     86   unsigned SaveTemporaryLabels : 1;
     87   unsigned GenDwarfForAssembly : 1;
     88   std::string DwarfDebugFlags;
     89   std::string DwarfDebugProducer;
     90   std::string DebugCompilationDir;
     91   std::string MainFileName;
     92 
     93   /// @}
     94   /// @name Frontend Options
     95   /// @{
     96 
     97   std::string InputFile;
     98   std::vector<std::string> LLVMArgs;
     99   std::string OutputPath;
    100   enum FileType {
    101     FT_Asm,  ///< Assembly (.s) output, transliterate mode.
    102     FT_Null, ///< No output, for timing purposes.
    103     FT_Obj   ///< Object file output.
    104   };
    105   FileType OutputType;
    106   unsigned ShowHelp : 1;
    107   unsigned ShowVersion : 1;
    108 
    109   /// @}
    110   /// @name Transliterate Options
    111   /// @{
    112 
    113   unsigned OutputAsmVariant;
    114   unsigned ShowEncoding : 1;
    115   unsigned ShowInst : 1;
    116 
    117   /// @}
    118   /// @name Assembler Options
    119   /// @{
    120 
    121   unsigned RelaxAll : 1;
    122   unsigned NoExecStack : 1;
    123 
    124   /// @}
    125 
    126 public:
    127   AssemblerInvocation() {
    128     Triple = "";
    129     NoInitialTextSection = 0;
    130     InputFile = "-";
    131     OutputPath = "-";
    132     OutputType = FT_Asm;
    133     OutputAsmVariant = 0;
    134     ShowInst = 0;
    135     ShowEncoding = 0;
    136     RelaxAll = 0;
    137     NoExecStack = 0;
    138   }
    139 
    140   static bool CreateFromArgs(AssemblerInvocation &Res, const char **ArgBegin,
    141                              const char **ArgEnd, DiagnosticsEngine &Diags);
    142 };
    143 
    144 }
    145 
    146 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
    147                                          const char **ArgBegin,
    148                                          const char **ArgEnd,
    149                                          DiagnosticsEngine &Diags) {
    150   using namespace clang::driver::cc1asoptions;
    151   bool Success = true;
    152 
    153   // Parse the arguments.
    154   OwningPtr<OptTable> OptTbl(createCC1AsOptTable());
    155   unsigned MissingArgIndex, MissingArgCount;
    156   OwningPtr<InputArgList> Args(
    157     OptTbl->ParseArgs(ArgBegin, ArgEnd,MissingArgIndex, MissingArgCount));
    158 
    159   // Check for missing argument error.
    160   if (MissingArgCount) {
    161     Diags.Report(diag::err_drv_missing_argument)
    162       << Args->getArgString(MissingArgIndex) << MissingArgCount;
    163     Success = false;
    164   }
    165 
    166   // Issue errors on unknown arguments.
    167   for (arg_iterator it = Args->filtered_begin(cc1asoptions::OPT_UNKNOWN),
    168          ie = Args->filtered_end(); it != ie; ++it) {
    169     Diags.Report(diag::err_drv_unknown_argument) << (*it) ->getAsString(*Args);
    170     Success = false;
    171   }
    172 
    173   // Construct the invocation.
    174 
    175   // Target Options
    176   Opts.Triple = llvm::Triple::normalize(Args->getLastArgValue(OPT_triple));
    177   Opts.CPU = Args->getLastArgValue(OPT_target_cpu);
    178   Opts.Features = Args->getAllArgValues(OPT_target_feature);
    179 
    180   // Use the default target triple if unspecified.
    181   if (Opts.Triple.empty())
    182     Opts.Triple = llvm::sys::getDefaultTargetTriple();
    183 
    184   // Language Options
    185   Opts.IncludePaths = Args->getAllArgValues(OPT_I);
    186   Opts.NoInitialTextSection = Args->hasArg(OPT_n);
    187   Opts.SaveTemporaryLabels = Args->hasArg(OPT_L);
    188   Opts.GenDwarfForAssembly = Args->hasArg(OPT_g);
    189   Opts.DwarfDebugFlags = Args->getLastArgValue(OPT_dwarf_debug_flags);
    190   Opts.DwarfDebugProducer = Args->getLastArgValue(OPT_dwarf_debug_producer);
    191   Opts.DebugCompilationDir = Args->getLastArgValue(OPT_fdebug_compilation_dir);
    192   Opts.MainFileName = Args->getLastArgValue(OPT_main_file_name);
    193 
    194   // Frontend Options
    195   if (Args->hasArg(OPT_INPUT)) {
    196     bool First = true;
    197     for (arg_iterator it = Args->filtered_begin(OPT_INPUT),
    198            ie = Args->filtered_end(); it != ie; ++it, First=false) {
    199       const Arg *A = it;
    200       if (First)
    201         Opts.InputFile = A->getValue();
    202       else {
    203         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(*Args);
    204         Success = false;
    205       }
    206     }
    207   }
    208   Opts.LLVMArgs = Args->getAllArgValues(OPT_mllvm);
    209   Opts.OutputPath = Args->getLastArgValue(OPT_o);
    210   if (Arg *A = Args->getLastArg(OPT_filetype)) {
    211     StringRef Name = A->getValue();
    212     unsigned OutputType = StringSwitch<unsigned>(Name)
    213       .Case("asm", FT_Asm)
    214       .Case("null", FT_Null)
    215       .Case("obj", FT_Obj)
    216       .Default(~0U);
    217     if (OutputType == ~0U) {
    218       Diags.Report(diag::err_drv_invalid_value)
    219         << A->getAsString(*Args) << Name;
    220       Success = false;
    221     } else
    222       Opts.OutputType = FileType(OutputType);
    223   }
    224   Opts.ShowHelp = Args->hasArg(OPT_help);
    225   Opts.ShowVersion = Args->hasArg(OPT_version);
    226 
    227   // Transliterate Options
    228   Opts.OutputAsmVariant =
    229       getLastArgIntValue(*Args.get(), OPT_output_asm_variant, 0, Diags);
    230   Opts.ShowEncoding = Args->hasArg(OPT_show_encoding);
    231   Opts.ShowInst = Args->hasArg(OPT_show_inst);
    232 
    233   // Assemble Options
    234   Opts.RelaxAll = Args->hasArg(OPT_mrelax_all);
    235   Opts.NoExecStack =  Args->hasArg(OPT_mno_exec_stack);
    236 
    237   return Success;
    238 }
    239 
    240 static formatted_raw_ostream *GetOutputStream(AssemblerInvocation &Opts,
    241                                               DiagnosticsEngine &Diags,
    242                                               bool Binary) {
    243   if (Opts.OutputPath.empty())
    244     Opts.OutputPath = "-";
    245 
    246   // Make sure that the Out file gets unlinked from the disk if we get a
    247   // SIGINT.
    248   if (Opts.OutputPath != "-")
    249     sys::RemoveFileOnSignal(Opts.OutputPath);
    250 
    251   std::string Error;
    252   raw_fd_ostream *Out =
    253       new raw_fd_ostream(Opts.OutputPath.c_str(), Error,
    254                          (Binary ? sys::fs::F_Binary : sys::fs::F_None));
    255   if (!Error.empty()) {
    256     Diags.Report(diag::err_fe_unable_to_open_output)
    257       << Opts.OutputPath << Error;
    258     return 0;
    259   }
    260 
    261   return new formatted_raw_ostream(*Out, formatted_raw_ostream::DELETE_STREAM);
    262 }
    263 
    264 static bool ExecuteAssembler(AssemblerInvocation &Opts,
    265                              DiagnosticsEngine &Diags) {
    266   // Get the target specific parser.
    267   std::string Error;
    268   const Target *TheTarget(TargetRegistry::lookupTarget(Opts.Triple, Error));
    269   if (!TheTarget) {
    270     Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    271     return false;
    272   }
    273 
    274   OwningPtr<MemoryBuffer> BufferPtr;
    275   if (error_code ec = MemoryBuffer::getFileOrSTDIN(Opts.InputFile, BufferPtr)) {
    276     Error = ec.message();
    277     Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
    278     return false;
    279   }
    280   MemoryBuffer *Buffer = BufferPtr.take();
    281 
    282   SourceMgr SrcMgr;
    283 
    284   // Tell SrcMgr about this buffer, which is what the parser will pick up.
    285   SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
    286 
    287   // Record the location of the include directories so that the lexer can find
    288   // it later.
    289   SrcMgr.setIncludeDirs(Opts.IncludePaths);
    290 
    291   OwningPtr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
    292   assert(MRI && "Unable to create target register info!");
    293 
    294   OwningPtr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, Opts.Triple));
    295   assert(MAI && "Unable to create target asm info!");
    296 
    297   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
    298   formatted_raw_ostream *Out = GetOutputStream(Opts, Diags, IsBinary);
    299   if (!Out)
    300     return false;
    301 
    302   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
    303   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
    304   OwningPtr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
    305   MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &SrcMgr);
    306   // FIXME: Assembler behavior can change with -static.
    307   MOFI->InitMCObjectFileInfo(Opts.Triple,
    308                              Reloc::Default, CodeModel::Default, Ctx);
    309   if (Opts.SaveTemporaryLabels)
    310     Ctx.setAllowTemporaryLabels(false);
    311   if (Opts.GenDwarfForAssembly)
    312     Ctx.setGenDwarfForAssembly(true);
    313   if (!Opts.DwarfDebugFlags.empty())
    314     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
    315   if (!Opts.DwarfDebugProducer.empty())
    316     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
    317   if (!Opts.DebugCompilationDir.empty())
    318     Ctx.setCompilationDir(Opts.DebugCompilationDir);
    319   if (!Opts.MainFileName.empty())
    320     Ctx.setMainFileName(StringRef(Opts.MainFileName));
    321 
    322   // Build up the feature string from the target feature list.
    323   std::string FS;
    324   if (!Opts.Features.empty()) {
    325     FS = Opts.Features[0];
    326     for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
    327       FS += "," + Opts.Features[i];
    328   }
    329 
    330   OwningPtr<MCStreamer> Str;
    331 
    332   OwningPtr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
    333   OwningPtr<MCSubtargetInfo>
    334     STI(TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
    335 
    336   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
    337   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
    338     MCInstPrinter *IP =
    339       TheTarget->createMCInstPrinter(Opts.OutputAsmVariant, *MAI, *MCII, *MRI,
    340                                      *STI);
    341     MCCodeEmitter *CE = 0;
    342     MCAsmBackend *MAB = 0;
    343     if (Opts.ShowEncoding) {
    344       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, *STI, Ctx);
    345       MAB = TheTarget->createMCAsmBackend(Opts.Triple, Opts.CPU);
    346     }
    347     Str.reset(TheTarget->createAsmStreamer(Ctx, *Out, /*asmverbose*/true,
    348                                            /*useLoc*/ true,
    349                                            /*useCFI*/ true,
    350                                            /*useDwarfDirectory*/ true,
    351                                            IP, CE, MAB,
    352                                            Opts.ShowInst));
    353   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
    354     Str.reset(createNullStreamer(Ctx));
    355   } else {
    356     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
    357            "Invalid file type!");
    358     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, *STI, Ctx);
    359     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(Opts.Triple, Opts.CPU);
    360     Str.reset(TheTarget->createMCObjectStreamer(Opts.Triple, Ctx, *MAB, *Out,
    361                                                 CE, Opts.RelaxAll,
    362                                                 Opts.NoExecStack));
    363     Str.get()->InitSections();
    364   }
    365 
    366   OwningPtr<MCAsmParser> Parser(createMCAsmParser(SrcMgr, Ctx,
    367                                                   *Str.get(), *MAI));
    368   OwningPtr<MCTargetAsmParser> TAP(TheTarget->createMCAsmParser(*STI, *Parser));
    369   if (!TAP) {
    370     Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    371     return false;
    372   }
    373 
    374   Parser->setTargetParser(*TAP.get());
    375 
    376   bool Success = !Parser->Run(Opts.NoInitialTextSection);
    377 
    378   // Close the output.
    379   delete Out;
    380 
    381   // Delete output on errors.
    382   if (!Success && Opts.OutputPath != "-")
    383     sys::fs::remove(Opts.OutputPath);
    384 
    385   return Success;
    386 }
    387 
    388 static void LLVMErrorHandler(void *UserData, const std::string &Message,
    389                              bool GenCrashDiag) {
    390   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
    391 
    392   Diags.Report(diag::err_fe_error_backend) << Message;
    393 
    394   // We cannot recover from llvm errors.
    395   exit(1);
    396 }
    397 
    398 int cc1as_main(const char **ArgBegin, const char **ArgEnd,
    399                const char *Argv0, void *MainAddr) {
    400   // Print a stack trace if we signal out.
    401   sys::PrintStackTraceOnErrorSignal();
    402   PrettyStackTraceProgram X(ArgEnd - ArgBegin, ArgBegin);
    403   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    404 
    405   // Initialize targets and assembly printers/parsers.
    406   InitializeAllTargetInfos();
    407   InitializeAllTargetMCs();
    408   InitializeAllAsmParsers();
    409 
    410   // Construct our diagnostic client.
    411   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
    412   TextDiagnosticPrinter *DiagClient
    413     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
    414   DiagClient->setPrefix("clang -cc1as");
    415   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
    416   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
    417 
    418   // Set an error handler, so that any LLVM backend diagnostics go through our
    419   // error handler.
    420   ScopedFatalErrorHandler FatalErrorHandler
    421     (LLVMErrorHandler, static_cast<void*>(&Diags));
    422 
    423   // Parse the arguments.
    424   AssemblerInvocation Asm;
    425   if (!AssemblerInvocation::CreateFromArgs(Asm, ArgBegin, ArgEnd, Diags))
    426     return 1;
    427 
    428   // Honor -help.
    429   if (Asm.ShowHelp) {
    430     OwningPtr<OptTable> Opts(driver::createCC1AsOptTable());
    431     Opts->PrintHelp(llvm::outs(), "clang -cc1as", "Clang Integrated Assembler");
    432     return 0;
    433   }
    434 
    435   // Honor -version.
    436   //
    437   // FIXME: Use a better -version message?
    438   if (Asm.ShowVersion) {
    439     llvm::cl::PrintVersionMessage();
    440     return 0;
    441   }
    442 
    443   // Honor -mllvm.
    444   //
    445   // FIXME: Remove this, one day.
    446   if (!Asm.LLVMArgs.empty()) {
    447     unsigned NumArgs = Asm.LLVMArgs.size();
    448     const char **Args = new const char*[NumArgs + 2];
    449     Args[0] = "clang (LLVM option parsing)";
    450     for (unsigned i = 0; i != NumArgs; ++i)
    451       Args[i + 1] = Asm.LLVMArgs[i].c_str();
    452     Args[NumArgs + 1] = 0;
    453     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args);
    454   }
    455 
    456   // Execute the invocation, unless there were parsing errors.
    457   bool Success = false;
    458   if (!Diags.hasErrorOccurred())
    459     Success = ExecuteAssembler(Asm, Diags);
    460 
    461   // If any timers were active but haven't been destroyed yet, print their
    462   // results now.
    463   TimerGroup::printAll(errs());
    464 
    465   return !Success;
    466 }
    467