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/MCObjectWriter.h"
33 #include "llvm/MC/MCParser/MCAsmParser.h"
34 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
35 #include "llvm/MC/MCRegisterInfo.h"
36 #include "llvm/MC/MCSectionMachO.h"
37 #include "llvm/MC/MCStreamer.h"
38 #include "llvm/MC/MCSubtargetInfo.h"
39 #include "llvm/MC/MCTargetOptions.h"
40 #include "llvm/Option/Arg.h"
41 #include "llvm/Option/ArgList.h"
42 #include "llvm/Option/OptTable.h"
43 #include "llvm/Support/CommandLine.h"
44 #include "llvm/Support/ErrorHandling.h"
45 #include "llvm/Support/FileSystem.h"
46 #include "llvm/Support/FormattedStream.h"
47 #include "llvm/Support/Host.h"
48 #include "llvm/Support/MemoryBuffer.h"
49 #include "llvm/Support/Path.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 /// 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   /// The list of symbol definitions.
83   std::vector<std::string> SymbolDefs;
84 
85   /// @}
86   /// @name Language Options
87   /// @{
88 
89   std::vector<std::string> IncludePaths;
90   unsigned NoInitialTextSection : 1;
91   unsigned SaveTemporaryLabels : 1;
92   unsigned GenDwarfForAssembly : 1;
93   unsigned RelaxELFRelocations : 1;
94   unsigned DwarfVersion;
95   std::string DwarfDebugFlags;
96   std::string DwarfDebugProducer;
97   std::string DebugCompilationDir;
98   std::map<const std::string, const std::string> DebugPrefixMap;
99   llvm::DebugCompressionType CompressDebugSections =
100       llvm::DebugCompressionType::None;
101   std::string MainFileName;
102   std::string SplitDwarfFile;
103 
104   /// @}
105   /// @name Frontend Options
106   /// @{
107 
108   std::string InputFile;
109   std::vector<std::string> LLVMArgs;
110   std::string OutputPath;
111   enum FileType {
112     FT_Asm,  ///< Assembly (.s) output, transliterate mode.
113     FT_Null, ///< No output, for timing purposes.
114     FT_Obj   ///< Object file output.
115   };
116   FileType OutputType;
117   unsigned ShowHelp : 1;
118   unsigned ShowVersion : 1;
119 
120   /// @}
121   /// @name Transliterate Options
122   /// @{
123 
124   unsigned OutputAsmVariant;
125   unsigned ShowEncoding : 1;
126   unsigned ShowInst : 1;
127 
128   /// @}
129   /// @name Assembler Options
130   /// @{
131 
132   unsigned RelaxAll : 1;
133   unsigned NoExecStack : 1;
134   unsigned FatalWarnings : 1;
135   unsigned IncrementalLinkerCompatible : 1;
136   unsigned EmbedBitcode : 1;
137 
138   /// The name of the relocation model to use.
139   std::string RelocationModel;
140 
141   /// @}
142 
143 public:
144   AssemblerInvocation() {
145     Triple = "";
146     NoInitialTextSection = 0;
147     InputFile = "-";
148     OutputPath = "-";
149     OutputType = FT_Asm;
150     OutputAsmVariant = 0;
151     ShowInst = 0;
152     ShowEncoding = 0;
153     RelaxAll = 0;
154     NoExecStack = 0;
155     FatalWarnings = 0;
156     IncrementalLinkerCompatible = 0;
157     DwarfVersion = 0;
158     EmbedBitcode = 0;
159   }
160 
161   static bool CreateFromArgs(AssemblerInvocation &Res,
162                              ArrayRef<const char *> Argv,
163                              DiagnosticsEngine &Diags);
164 };
165 
166 }
167 
168 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
169                                          ArrayRef<const char *> Argv,
170                                          DiagnosticsEngine &Diags) {
171   bool Success = true;
172 
173   // Parse the arguments.
174   std::unique_ptr<OptTable> OptTbl(createDriverOptTable());
175 
176   const unsigned IncludedFlagsBitmask = options::CC1AsOption;
177   unsigned MissingArgIndex, MissingArgCount;
178   InputArgList Args = OptTbl->ParseArgs(Argv, MissingArgIndex, MissingArgCount,
179                                         IncludedFlagsBitmask);
180 
181   // Check for missing argument error.
182   if (MissingArgCount) {
183     Diags.Report(diag::err_drv_missing_argument)
184         << Args.getArgString(MissingArgIndex) << MissingArgCount;
185     Success = false;
186   }
187 
188   // Issue errors on unknown arguments.
189   for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {
190     auto ArgString = A->getAsString(Args);
191     std::string Nearest;
192     if (OptTbl->findNearest(ArgString, Nearest, IncludedFlagsBitmask) > 1)
193       Diags.Report(diag::err_drv_unknown_argument) << ArgString;
194     else
195       Diags.Report(diag::err_drv_unknown_argument_with_suggestion)
196           << ArgString << Nearest;
197     Success = false;
198   }
199 
200   // Construct the invocation.
201 
202   // Target Options
203   Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
204   Opts.CPU = Args.getLastArgValue(OPT_target_cpu);
205   Opts.Features = Args.getAllArgValues(OPT_target_feature);
206 
207   // Use the default target triple if unspecified.
208   if (Opts.Triple.empty())
209     Opts.Triple = llvm::sys::getDefaultTargetTriple();
210 
211   // Language Options
212   Opts.IncludePaths = Args.getAllArgValues(OPT_I);
213   Opts.NoInitialTextSection = Args.hasArg(OPT_n);
214   Opts.SaveTemporaryLabels = Args.hasArg(OPT_msave_temp_labels);
215   // Any DebugInfoKind implies GenDwarfForAssembly.
216   Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);
217 
218   if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections,
219                                      OPT_compress_debug_sections_EQ)) {
220     if (A->getOption().getID() == OPT_compress_debug_sections) {
221       // TODO: be more clever about the compression type auto-detection
222       Opts.CompressDebugSections = llvm::DebugCompressionType::GNU;
223     } else {
224       Opts.CompressDebugSections =
225           llvm::StringSwitch<llvm::DebugCompressionType>(A->getValue())
226               .Case("none", llvm::DebugCompressionType::None)
227               .Case("zlib", llvm::DebugCompressionType::Z)
228               .Case("zlib-gnu", llvm::DebugCompressionType::GNU)
229               .Default(llvm::DebugCompressionType::None);
230     }
231   }
232 
233   Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);
234   Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);
235   Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
236   Opts.DwarfDebugProducer = Args.getLastArgValue(OPT_dwarf_debug_producer);
237   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
238   Opts.MainFileName = Args.getLastArgValue(OPT_main_file_name);
239 
240   for (const auto &Arg : Args.getAllArgValues(OPT_fdebug_prefix_map_EQ))
241     Opts.DebugPrefixMap.insert(StringRef(Arg).split('='));
242 
243   // Frontend Options
244   if (Args.hasArg(OPT_INPUT)) {
245     bool First = true;
246     for (const Arg *A : Args.filtered(OPT_INPUT)) {
247       if (First) {
248         Opts.InputFile = A->getValue();
249         First = false;
250       } else {
251         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
252         Success = false;
253       }
254     }
255   }
256   Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
257   Opts.OutputPath = Args.getLastArgValue(OPT_o);
258   Opts.SplitDwarfFile = Args.getLastArgValue(OPT_split_dwarf_file);
259   if (Arg *A = Args.getLastArg(OPT_filetype)) {
260     StringRef Name = A->getValue();
261     unsigned OutputType = StringSwitch<unsigned>(Name)
262       .Case("asm", FT_Asm)
263       .Case("null", FT_Null)
264       .Case("obj", FT_Obj)
265       .Default(~0U);
266     if (OutputType == ~0U) {
267       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
268       Success = false;
269     } else
270       Opts.OutputType = FileType(OutputType);
271   }
272   Opts.ShowHelp = Args.hasArg(OPT_help);
273   Opts.ShowVersion = Args.hasArg(OPT_version);
274 
275   // Transliterate Options
276   Opts.OutputAsmVariant =
277       getLastArgIntValue(Args, OPT_output_asm_variant, 0, Diags);
278   Opts.ShowEncoding = Args.hasArg(OPT_show_encoding);
279   Opts.ShowInst = Args.hasArg(OPT_show_inst);
280 
281   // Assemble Options
282   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
283   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
284   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
285   Opts.RelocationModel = Args.getLastArgValue(OPT_mrelocation_model, "pic");
286   Opts.IncrementalLinkerCompatible =
287       Args.hasArg(OPT_mincremental_linker_compatible);
288   Opts.SymbolDefs = Args.getAllArgValues(OPT_defsym);
289 
290   // EmbedBitcode Option. If -fembed-bitcode is enabled, set the flag.
291   // EmbedBitcode behaves the same for all embed options for assembly files.
292   if (auto *A = Args.getLastArg(OPT_fembed_bitcode_EQ)) {
293     Opts.EmbedBitcode = llvm::StringSwitch<unsigned>(A->getValue())
294                             .Case("all", 1)
295                             .Case("bitcode", 1)
296                             .Case("marker", 1)
297                             .Default(0);
298   }
299 
300   return Success;
301 }
302 
303 static std::unique_ptr<raw_fd_ostream>
304 getOutputStream(StringRef Path, DiagnosticsEngine &Diags, bool Binary) {
305   // Make sure that the Out file gets unlinked from the disk if we get a
306   // SIGINT.
307   if (Path != "-")
308     sys::RemoveFileOnSignal(Path);
309 
310   std::error_code EC;
311   auto Out = llvm::make_unique<raw_fd_ostream>(
312       Path, EC, (Binary ? sys::fs::F_None : sys::fs::F_Text));
313   if (EC) {
314     Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
315     return nullptr;
316   }
317 
318   return Out;
319 }
320 
321 static bool ExecuteAssembler(AssemblerInvocation &Opts,
322                              DiagnosticsEngine &Diags) {
323   // Get the target specific parser.
324   std::string Error;
325   const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
326   if (!TheTarget)
327     return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
328 
329   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
330       MemoryBuffer::getFileOrSTDIN(Opts.InputFile);
331 
332   if (std::error_code EC = Buffer.getError()) {
333     Error = EC.message();
334     return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
335   }
336 
337   SourceMgr SrcMgr;
338 
339   // Tell SrcMgr about this buffer, which is what the parser will pick up.
340   SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
341 
342   // Record the location of the include directories so that the lexer can find
343   // it later.
344   SrcMgr.setIncludeDirs(Opts.IncludePaths);
345 
346   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
347   assert(MRI && "Unable to create target register info!");
348 
349   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, Opts.Triple));
350   assert(MAI && "Unable to create target asm info!");
351 
352   // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
353   // may be created with a combination of default and explicit settings.
354   MAI->setCompressDebugSections(Opts.CompressDebugSections);
355 
356   MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);
357 
358   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
359   if (Opts.OutputPath.empty())
360     Opts.OutputPath = "-";
361   std::unique_ptr<raw_fd_ostream> FDOS =
362       getOutputStream(Opts.OutputPath, Diags, IsBinary);
363   if (!FDOS)
364     return true;
365   std::unique_ptr<raw_fd_ostream> DwoOS;
366   if (!Opts.SplitDwarfFile.empty())
367     DwoOS = getOutputStream(Opts.SplitDwarfFile, Diags, IsBinary);
368 
369   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
370   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
371   std::unique_ptr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
372 
373   MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &SrcMgr);
374 
375   bool PIC = false;
376   if (Opts.RelocationModel == "static") {
377     PIC = false;
378   } else if (Opts.RelocationModel == "pic") {
379     PIC = true;
380   } else {
381     assert(Opts.RelocationModel == "dynamic-no-pic" &&
382            "Invalid PIC model!");
383     PIC = false;
384   }
385 
386   MOFI->InitMCObjectFileInfo(Triple(Opts.Triple), PIC, Ctx);
387   if (Opts.SaveTemporaryLabels)
388     Ctx.setAllowTemporaryLabels(false);
389   if (Opts.GenDwarfForAssembly)
390     Ctx.setGenDwarfForAssembly(true);
391   if (!Opts.DwarfDebugFlags.empty())
392     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
393   if (!Opts.DwarfDebugProducer.empty())
394     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
395   if (!Opts.DebugCompilationDir.empty())
396     Ctx.setCompilationDir(Opts.DebugCompilationDir);
397   if (!Opts.DebugPrefixMap.empty())
398     for (const auto &KV : Opts.DebugPrefixMap)
399       Ctx.addDebugPrefixMapEntry(KV.first, KV.second);
400   if (!Opts.MainFileName.empty())
401     Ctx.setMainFileName(StringRef(Opts.MainFileName));
402   Ctx.setDwarfVersion(Opts.DwarfVersion);
403 
404   // Build up the feature string from the target feature list.
405   std::string FS;
406   if (!Opts.Features.empty()) {
407     FS = Opts.Features[0];
408     for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
409       FS += "," + Opts.Features[i];
410   }
411 
412   std::unique_ptr<MCStreamer> Str;
413 
414   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
415   std::unique_ptr<MCSubtargetInfo> STI(
416       TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
417 
418   raw_pwrite_stream *Out = FDOS.get();
419   std::unique_ptr<buffer_ostream> BOS;
420 
421   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
422   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
423     MCInstPrinter *IP = TheTarget->createMCInstPrinter(
424         llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
425 
426     std::unique_ptr<MCCodeEmitter> CE;
427     if (Opts.ShowEncoding)
428       CE.reset(TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
429     MCTargetOptions MCOptions;
430     std::unique_ptr<MCAsmBackend> MAB(
431         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
432 
433     auto FOut = llvm::make_unique<formatted_raw_ostream>(*Out);
434     Str.reset(TheTarget->createAsmStreamer(
435         Ctx, std::move(FOut), /*asmverbose*/ true,
436         /*useDwarfDirectory*/ true, IP, std::move(CE), std::move(MAB),
437         Opts.ShowInst));
438   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
439     Str.reset(createNullStreamer(Ctx));
440   } else {
441     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
442            "Invalid file type!");
443     if (!FDOS->supportsSeeking()) {
444       BOS = make_unique<buffer_ostream>(*FDOS);
445       Out = BOS.get();
446     }
447 
448     std::unique_ptr<MCCodeEmitter> CE(
449         TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
450     MCTargetOptions MCOptions;
451     std::unique_ptr<MCAsmBackend> MAB(
452         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
453     std::unique_ptr<MCObjectWriter> OW =
454         DwoOS ? MAB->createDwoObjectWriter(*Out, *DwoOS)
455               : MAB->createObjectWriter(*Out);
456 
457     Triple T(Opts.Triple);
458     Str.reset(TheTarget->createMCObjectStreamer(
459         T, Ctx, std::move(MAB), std::move(OW), std::move(CE), *STI,
460         Opts.RelaxAll, Opts.IncrementalLinkerCompatible,
461         /*DWARFMustBeAtTheEnd*/ true));
462     Str.get()->InitSections(Opts.NoExecStack);
463   }
464 
465   // When -fembed-bitcode is passed to clang_as, a 1-byte marker
466   // is emitted in __LLVM,__asm section if the object file is MachO format.
467   if (Opts.EmbedBitcode && Ctx.getObjectFileInfo()->getObjectFileType() ==
468                                MCObjectFileInfo::IsMachO) {
469     MCSection *AsmLabel = Ctx.getMachOSection(
470         "__LLVM", "__asm", MachO::S_REGULAR, 4, SectionKind::getReadOnly());
471     Str.get()->SwitchSection(AsmLabel);
472     Str.get()->EmitZeros(1);
473   }
474 
475   // Assembly to object compilation should leverage assembly info.
476   Str->setUseAssemblerInfoForParsing(true);
477 
478   bool Failed = false;
479 
480   std::unique_ptr<MCAsmParser> Parser(
481       createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
482 
483   // FIXME: init MCTargetOptions from sanitizer flags here.
484   MCTargetOptions Options;
485   std::unique_ptr<MCTargetAsmParser> TAP(
486       TheTarget->createMCAsmParser(*STI, *Parser, *MCII, Options));
487   if (!TAP)
488     Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
489 
490   // Set values for symbols, if any.
491   for (auto &S : Opts.SymbolDefs) {
492     auto Pair = StringRef(S).split('=');
493     auto Sym = Pair.first;
494     auto Val = Pair.second;
495     int64_t Value;
496     // We have already error checked this in the driver.
497     Val.getAsInteger(0, Value);
498     Ctx.setSymbolValue(Parser->getStreamer(), Sym, Value);
499   }
500 
501   if (!Failed) {
502     Parser->setTargetParser(*TAP.get());
503     Failed = Parser->Run(Opts.NoInitialTextSection);
504   }
505 
506   // Close Streamer first.
507   // It might have a reference to the output stream.
508   Str.reset();
509   // Close the output stream early.
510   BOS.reset();
511   FDOS.reset();
512 
513   // Delete output file if there were errors.
514   if (Failed) {
515     if (Opts.OutputPath != "-")
516       sys::fs::remove(Opts.OutputPath);
517     if (!Opts.SplitDwarfFile.empty() && Opts.SplitDwarfFile != "-")
518       sys::fs::remove(Opts.SplitDwarfFile);
519   }
520 
521   return Failed;
522 }
523 
524 static void LLVMErrorHandler(void *UserData, const std::string &Message,
525                              bool GenCrashDiag) {
526   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
527 
528   Diags.Report(diag::err_fe_error_backend) << Message;
529 
530   // We cannot recover from llvm errors.
531   exit(1);
532 }
533 
534 int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
535   // Initialize targets and assembly printers/parsers.
536   InitializeAllTargetInfos();
537   InitializeAllTargetMCs();
538   InitializeAllAsmParsers();
539 
540   // Construct our diagnostic client.
541   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
542   TextDiagnosticPrinter *DiagClient
543     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
544   DiagClient->setPrefix("clang -cc1as");
545   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
546   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
547 
548   // Set an error handler, so that any LLVM backend diagnostics go through our
549   // error handler.
550   ScopedFatalErrorHandler FatalErrorHandler
551     (LLVMErrorHandler, static_cast<void*>(&Diags));
552 
553   // Parse the arguments.
554   AssemblerInvocation Asm;
555   if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
556     return 1;
557 
558   if (Asm.ShowHelp) {
559     std::unique_ptr<OptTable> Opts(driver::createDriverOptTable());
560     Opts->PrintHelp(llvm::outs(), "clang -cc1as [options] file...",
561                     "Clang Integrated Assembler",
562                     /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0,
563                     /*ShowAllAliases=*/false);
564     return 0;
565   }
566 
567   // Honor -version.
568   //
569   // FIXME: Use a better -version message?
570   if (Asm.ShowVersion) {
571     llvm::cl::PrintVersionMessage();
572     return 0;
573   }
574 
575   // Honor -mllvm.
576   //
577   // FIXME: Remove this, one day.
578   if (!Asm.LLVMArgs.empty()) {
579     unsigned NumArgs = Asm.LLVMArgs.size();
580     auto Args = llvm::make_unique<const char*[]>(NumArgs + 2);
581     Args[0] = "clang (LLVM option parsing)";
582     for (unsigned i = 0; i != NumArgs; ++i)
583       Args[i + 1] = Asm.LLVMArgs[i].c_str();
584     Args[NumArgs + 1] = nullptr;
585     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());
586   }
587 
588   // Execute the invocation, unless there were parsing errors.
589   bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
590 
591   // If any timers were active but haven't been destroyed yet, print their
592   // results now.
593   TimerGroup::printAll(errs());
594 
595   return !!Failed;
596 }
597