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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 
    129   /// @}
    130 
    131 public:
    132   AssemblerInvocation() {
    133     Triple = "";
    134     NoInitialTextSection = 0;
    135     InputFile = "-";
    136     OutputPath = "-";
    137     OutputType = FT_Asm;
    138     OutputAsmVariant = 0;
    139     ShowInst = 0;
    140     ShowEncoding = 0;
    141     RelaxAll = 0;
    142     NoExecStack = 0;
    143     FatalWarnings = 0;
    144     DwarfVersion = 3;
    145   }
    146 
    147   static bool CreateFromArgs(AssemblerInvocation &Res,
    148                              ArrayRef<const char *> Argv,
    149                              DiagnosticsEngine &Diags);
    150 };
    151 
    152 }
    153 
    154 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
    155                                          ArrayRef<const char *> Argv,
    156                                          DiagnosticsEngine &Diags) {
    157   bool Success = true;
    158 
    159   // Parse the arguments.
    160   std::unique_ptr<OptTable> OptTbl(createDriverOptTable());
    161 
    162   const unsigned IncludedFlagsBitmask = options::CC1AsOption;
    163   unsigned MissingArgIndex, MissingArgCount;
    164   std::unique_ptr<InputArgList> Args(
    165       OptTbl->ParseArgs(Argv.begin(), Argv.end(), MissingArgIndex, MissingArgCount,
    166                         IncludedFlagsBitmask));
    167 
    168   // Check for missing argument error.
    169   if (MissingArgCount) {
    170     Diags.Report(diag::err_drv_missing_argument)
    171         << Args->getArgString(MissingArgIndex) << MissingArgCount;
    172     Success = false;
    173   }
    174 
    175   // Issue errors on unknown arguments.
    176   for (arg_iterator it = Args->filtered_begin(OPT_UNKNOWN),
    177                     ie = Args->filtered_end();
    178        it != ie; ++it) {
    179     Diags.Report(diag::err_drv_unknown_argument) << (*it)->getAsString(*Args);
    180     Success = false;
    181   }
    182 
    183   // Construct the invocation.
    184 
    185   // Target Options
    186   Opts.Triple = llvm::Triple::normalize(Args->getLastArgValue(OPT_triple));
    187   Opts.CPU = Args->getLastArgValue(OPT_target_cpu);
    188   Opts.Features = Args->getAllArgValues(OPT_target_feature);
    189 
    190   // Use the default target triple if unspecified.
    191   if (Opts.Triple.empty())
    192     Opts.Triple = llvm::sys::getDefaultTargetTriple();
    193 
    194   // Language Options
    195   Opts.IncludePaths = Args->getAllArgValues(OPT_I);
    196   Opts.NoInitialTextSection = Args->hasArg(OPT_n);
    197   Opts.SaveTemporaryLabels = Args->hasArg(OPT_msave_temp_labels);
    198   Opts.GenDwarfForAssembly = Args->hasArg(OPT_g_Flag);
    199   Opts.CompressDebugSections = Args->hasArg(OPT_compress_debug_sections);
    200   if (Args->hasArg(OPT_gdwarf_2))
    201     Opts.DwarfVersion = 2;
    202   if (Args->hasArg(OPT_gdwarf_3))
    203     Opts.DwarfVersion = 3;
    204   if (Args->hasArg(OPT_gdwarf_4))
    205     Opts.DwarfVersion = 4;
    206   Opts.DwarfDebugFlags = Args->getLastArgValue(OPT_dwarf_debug_flags);
    207   Opts.DwarfDebugProducer = Args->getLastArgValue(OPT_dwarf_debug_producer);
    208   Opts.DebugCompilationDir = Args->getLastArgValue(OPT_fdebug_compilation_dir);
    209   Opts.MainFileName = Args->getLastArgValue(OPT_main_file_name);
    210 
    211   // Frontend Options
    212   if (Args->hasArg(OPT_INPUT)) {
    213     bool First = true;
    214     for (arg_iterator it = Args->filtered_begin(OPT_INPUT),
    215            ie = Args->filtered_end(); it != ie; ++it, First=false) {
    216       const Arg *A = it;
    217       if (First)
    218         Opts.InputFile = A->getValue();
    219       else {
    220         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(*Args);
    221         Success = false;
    222       }
    223     }
    224   }
    225   Opts.LLVMArgs = Args->getAllArgValues(OPT_mllvm);
    226   Opts.OutputPath = Args->getLastArgValue(OPT_o);
    227   if (Arg *A = Args->getLastArg(OPT_filetype)) {
    228     StringRef Name = A->getValue();
    229     unsigned OutputType = StringSwitch<unsigned>(Name)
    230       .Case("asm", FT_Asm)
    231       .Case("null", FT_Null)
    232       .Case("obj", FT_Obj)
    233       .Default(~0U);
    234     if (OutputType == ~0U) {
    235       Diags.Report(diag::err_drv_invalid_value)
    236         << A->getAsString(*Args) << Name;
    237       Success = false;
    238     } else
    239       Opts.OutputType = FileType(OutputType);
    240   }
    241   Opts.ShowHelp = Args->hasArg(OPT_help);
    242   Opts.ShowVersion = Args->hasArg(OPT_version);
    243 
    244   // Transliterate Options
    245   Opts.OutputAsmVariant =
    246       getLastArgIntValue(*Args.get(), OPT_output_asm_variant, 0, Diags);
    247   Opts.ShowEncoding = Args->hasArg(OPT_show_encoding);
    248   Opts.ShowInst = Args->hasArg(OPT_show_inst);
    249 
    250   // Assemble Options
    251   Opts.RelaxAll = Args->hasArg(OPT_mrelax_all);
    252   Opts.NoExecStack = Args->hasArg(OPT_mno_exec_stack);
    253   Opts.FatalWarnings =  Args->hasArg(OPT_massembler_fatal_warnings);
    254 
    255   return Success;
    256 }
    257 
    258 static std::unique_ptr<raw_fd_ostream>
    259 getOutputStream(AssemblerInvocation &Opts, DiagnosticsEngine &Diags,
    260                 bool Binary) {
    261   if (Opts.OutputPath.empty())
    262     Opts.OutputPath = "-";
    263 
    264   // Make sure that the Out file gets unlinked from the disk if we get a
    265   // SIGINT.
    266   if (Opts.OutputPath != "-")
    267     sys::RemoveFileOnSignal(Opts.OutputPath);
    268 
    269   std::error_code EC;
    270   auto Out = llvm::make_unique<raw_fd_ostream>(
    271       Opts.OutputPath, EC, (Binary ? sys::fs::F_None : sys::fs::F_Text));
    272   if (EC) {
    273     Diags.Report(diag::err_fe_unable_to_open_output) << Opts.OutputPath
    274                                                      << EC.message();
    275     return nullptr;
    276   }
    277 
    278   return Out;
    279 }
    280 
    281 static bool ExecuteAssembler(AssemblerInvocation &Opts,
    282                              DiagnosticsEngine &Diags) {
    283   // Get the target specific parser.
    284   std::string Error;
    285   const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
    286   if (!TheTarget)
    287     return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    288 
    289   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
    290       MemoryBuffer::getFileOrSTDIN(Opts.InputFile);
    291 
    292   if (std::error_code EC = Buffer.getError()) {
    293     Error = EC.message();
    294     return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
    295   }
    296 
    297   SourceMgr SrcMgr;
    298 
    299   // Tell SrcMgr about this buffer, which is what the parser will pick up.
    300   SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
    301 
    302   // Record the location of the include directories so that the lexer can find
    303   // it later.
    304   SrcMgr.setIncludeDirs(Opts.IncludePaths);
    305 
    306   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
    307   assert(MRI && "Unable to create target register info!");
    308 
    309   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, Opts.Triple));
    310   assert(MAI && "Unable to create target asm info!");
    311 
    312   // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
    313   // may be created with a combination of default and explicit settings.
    314   if (Opts.CompressDebugSections)
    315     MAI->setCompressDebugSections(true);
    316 
    317   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
    318   std::unique_ptr<raw_fd_ostream> FDOS = getOutputStream(Opts, Diags, IsBinary);
    319   if (!FDOS)
    320     return true;
    321 
    322   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
    323   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
    324   std::unique_ptr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
    325 
    326   MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &SrcMgr);
    327   // FIXME: Assembler behavior can change with -static.
    328   MOFI->InitMCObjectFileInfo(Opts.Triple,
    329                              Reloc::Default, CodeModel::Default, Ctx);
    330   if (Opts.SaveTemporaryLabels)
    331     Ctx.setAllowTemporaryLabels(false);
    332   if (Opts.GenDwarfForAssembly)
    333     Ctx.setGenDwarfForAssembly(true);
    334   if (!Opts.DwarfDebugFlags.empty())
    335     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
    336   if (!Opts.DwarfDebugProducer.empty())
    337     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
    338   if (!Opts.DebugCompilationDir.empty())
    339     Ctx.setCompilationDir(Opts.DebugCompilationDir);
    340   if (!Opts.MainFileName.empty())
    341     Ctx.setMainFileName(StringRef(Opts.MainFileName));
    342   Ctx.setDwarfVersion(Opts.DwarfVersion);
    343 
    344   // Build up the feature string from the target feature list.
    345   std::string FS;
    346   if (!Opts.Features.empty()) {
    347     FS = Opts.Features[0];
    348     for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
    349       FS += "," + Opts.Features[i];
    350   }
    351 
    352   std::unique_ptr<MCStreamer> Str;
    353 
    354   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
    355   std::unique_ptr<MCSubtargetInfo> STI(
    356       TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
    357 
    358   raw_pwrite_stream *Out = FDOS.get();
    359   std::unique_ptr<buffer_ostream> BOS;
    360 
    361   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
    362   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
    363     MCInstPrinter *IP = TheTarget->createMCInstPrinter(
    364         llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
    365     MCCodeEmitter *CE = nullptr;
    366     MCAsmBackend *MAB = nullptr;
    367     if (Opts.ShowEncoding) {
    368       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
    369       MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple, Opts.CPU);
    370     }
    371     auto FOut = llvm::make_unique<formatted_raw_ostream>(*Out);
    372     Str.reset(TheTarget->createAsmStreamer(
    373         Ctx, std::move(FOut), /*asmverbose*/ true,
    374         /*useDwarfDirectory*/ true, IP, CE, MAB, Opts.ShowInst));
    375   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
    376     Str.reset(createNullStreamer(Ctx));
    377   } else {
    378     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
    379            "Invalid file type!");
    380     if (!FDOS->supportsSeeking()) {
    381       BOS = make_unique<buffer_ostream>(*FDOS);
    382       Out = BOS.get();
    383     }
    384 
    385     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
    386     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple,
    387                                                       Opts.CPU);
    388     Triple T(Opts.Triple);
    389     Str.reset(TheTarget->createMCObjectStreamer(T, Ctx, *MAB, *Out, CE, *STI,
    390                                                 Opts.RelaxAll,
    391                                                 /*DWARFMustBeAtTheEnd*/ true));
    392     Str.get()->InitSections(Opts.NoExecStack);
    393   }
    394 
    395   bool Failed = false;
    396 
    397   std::unique_ptr<MCAsmParser> Parser(
    398       createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
    399 
    400   // FIXME: init MCTargetOptions from sanitizer flags here.
    401   MCTargetOptions Options;
    402   std::unique_ptr<MCTargetAsmParser> TAP(
    403       TheTarget->createMCAsmParser(*STI, *Parser, *MCII, Options));
    404   if (!TAP)
    405     Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
    406 
    407   if (!Failed) {
    408     Parser->setTargetParser(*TAP.get());
    409     Failed = Parser->Run(Opts.NoInitialTextSection);
    410   }
    411 
    412   // Close the output stream early.
    413   BOS.reset();
    414   FDOS.reset();
    415 
    416   // Delete output file if there were errors.
    417   if (Failed && Opts.OutputPath != "-")
    418     sys::fs::remove(Opts.OutputPath);
    419 
    420   return Failed;
    421 }
    422 
    423 static void LLVMErrorHandler(void *UserData, const std::string &Message,
    424                              bool GenCrashDiag) {
    425   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
    426 
    427   Diags.Report(diag::err_fe_error_backend) << Message;
    428 
    429   // We cannot recover from llvm errors.
    430   exit(1);
    431 }
    432 
    433 int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
    434   // Print a stack trace if we signal out.
    435   sys::PrintStackTraceOnErrorSignal();
    436   PrettyStackTraceProgram X(Argv.size(), Argv.data());
    437   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    438 
    439   // Initialize targets and assembly printers/parsers.
    440   InitializeAllTargetInfos();
    441   InitializeAllTargetMCs();
    442   InitializeAllAsmParsers();
    443 
    444   // Construct our diagnostic client.
    445   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
    446   TextDiagnosticPrinter *DiagClient
    447     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
    448   DiagClient->setPrefix("clang -cc1as");
    449   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
    450   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
    451 
    452   // Set an error handler, so that any LLVM backend diagnostics go through our
    453   // error handler.
    454   ScopedFatalErrorHandler FatalErrorHandler
    455     (LLVMErrorHandler, static_cast<void*>(&Diags));
    456 
    457   // Parse the arguments.
    458   AssemblerInvocation Asm;
    459   if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
    460     return 1;
    461 
    462   if (Asm.ShowHelp) {
    463     std::unique_ptr<OptTable> Opts(driver::createDriverOptTable());
    464     Opts->PrintHelp(llvm::outs(), "clang -cc1as", "Clang Integrated Assembler",
    465                     /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0);
    466     return 0;
    467   }
    468 
    469   // Honor -version.
    470   //
    471   // FIXME: Use a better -version message?
    472   if (Asm.ShowVersion) {
    473     llvm::cl::PrintVersionMessage();
    474     return 0;
    475   }
    476 
    477   // Honor -mllvm.
    478   //
    479   // FIXME: Remove this, one day.
    480   if (!Asm.LLVMArgs.empty()) {
    481     unsigned NumArgs = Asm.LLVMArgs.size();
    482     const char **Args = new const char*[NumArgs + 2];
    483     Args[0] = "clang (LLVM option parsing)";
    484     for (unsigned i = 0; i != NumArgs; ++i)
    485       Args[i + 1] = Asm.LLVMArgs[i].c_str();
    486     Args[NumArgs + 1] = nullptr;
    487     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args);
    488   }
    489 
    490   // Execute the invocation, unless there were parsing errors.
    491   bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
    492 
    493   // If any timers were active but haven't been destroyed yet, print their
    494   // results now.
    495   TimerGroup::printAll(errs());
    496 
    497   return !!Failed;
    498 }
    499 
    500