1 //===-- cc1as_main.cpp - Clang Assembler  ---------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This is the entry point to the clang -cc1as functionality, which implements
10 // the direct interface to the LLVM MC based assembler.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Basic/Diagnostic.h"
15 #include "clang/Basic/DiagnosticOptions.h"
16 #include "clang/Driver/DriverDiagnostic.h"
17 #include "clang/Driver/Options.h"
18 #include "clang/Frontend/FrontendDiagnostic.h"
19 #include "clang/Frontend/TextDiagnosticPrinter.h"
20 #include "clang/Frontend/Utils.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/StringSwitch.h"
23 #include "llvm/ADT/Triple.h"
24 #include "llvm/IR/DataLayout.h"
25 #include "llvm/MC/MCAsmBackend.h"
26 #include "llvm/MC/MCAsmInfo.h"
27 #include "llvm/MC/MCCodeEmitter.h"
28 #include "llvm/MC/MCContext.h"
29 #include "llvm/MC/MCInstrInfo.h"
30 #include "llvm/MC/MCObjectFileInfo.h"
31 #include "llvm/MC/MCObjectWriter.h"
32 #include "llvm/MC/MCParser/MCAsmParser.h"
33 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
34 #include "llvm/MC/MCRegisterInfo.h"
35 #include "llvm/MC/MCSectionMachO.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSubtargetInfo.h"
38 #include "llvm/MC/MCTargetOptions.h"
39 #include "llvm/MC/TargetRegistry.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/Process.h"
51 #include "llvm/Support/Signals.h"
52 #include "llvm/Support/SourceMgr.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 Dwarf64 : 1;
95   unsigned DwarfVersion;
96   std::string DwarfDebugFlags;
97   std::string DwarfDebugProducer;
98   std::string DebugCompilationDir;
99   std::map<const std::string, const std::string> DebugPrefixMap;
100   llvm::DebugCompressionType CompressDebugSections =
101       llvm::DebugCompressionType::None;
102   std::string MainFileName;
103   std::string SplitDwarfOutput;
104 
105   /// @}
106   /// @name Frontend Options
107   /// @{
108 
109   std::string InputFile;
110   std::vector<std::string> LLVMArgs;
111   std::string OutputPath;
112   enum FileType {
113     FT_Asm,  ///< Assembly (.s) output, transliterate mode.
114     FT_Null, ///< No output, for timing purposes.
115     FT_Obj   ///< Object file output.
116   };
117   FileType OutputType;
118   unsigned ShowHelp : 1;
119   unsigned ShowVersion : 1;
120 
121   /// @}
122   /// @name Transliterate Options
123   /// @{
124 
125   unsigned OutputAsmVariant;
126   unsigned ShowEncoding : 1;
127   unsigned ShowInst : 1;
128 
129   /// @}
130   /// @name Assembler Options
131   /// @{
132 
133   unsigned RelaxAll : 1;
134   unsigned NoExecStack : 1;
135   unsigned FatalWarnings : 1;
136   unsigned NoWarn : 1;
137   unsigned IncrementalLinkerCompatible : 1;
138   unsigned EmbedBitcode : 1;
139 
140   /// The name of the relocation model to use.
141   std::string RelocationModel;
142 
143   /// The ABI targeted by the backend. Specified using -target-abi. Empty
144   /// otherwise.
145   std::string TargetABI;
146 
147   /// Darwin target variant triple, the variant of the deployment target
148   /// for which the code is being compiled.
149   llvm::Optional<llvm::Triple> DarwinTargetVariantTriple;
150   /// @}
151 
152 public:
153   AssemblerInvocation() {
154     Triple = "";
155     NoInitialTextSection = 0;
156     InputFile = "-";
157     OutputPath = "-";
158     OutputType = FT_Asm;
159     OutputAsmVariant = 0;
160     ShowInst = 0;
161     ShowEncoding = 0;
162     RelaxAll = 0;
163     NoExecStack = 0;
164     FatalWarnings = 0;
165     NoWarn = 0;
166     IncrementalLinkerCompatible = 0;
167     Dwarf64 = 0;
168     DwarfVersion = 0;
169     EmbedBitcode = 0;
170   }
171 
172   static bool CreateFromArgs(AssemblerInvocation &Res,
173                              ArrayRef<const char *> Argv,
174                              DiagnosticsEngine &Diags);
175 };
176 
177 }
178 
179 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
180                                          ArrayRef<const char *> Argv,
181                                          DiagnosticsEngine &Diags) {
182   bool Success = true;
183 
184   // Parse the arguments.
185   const OptTable &OptTbl = getDriverOptTable();
186 
187   const unsigned IncludedFlagsBitmask = options::CC1AsOption;
188   unsigned MissingArgIndex, MissingArgCount;
189   InputArgList Args = OptTbl.ParseArgs(Argv, MissingArgIndex, MissingArgCount,
190                                        IncludedFlagsBitmask);
191 
192   // Check for missing argument error.
193   if (MissingArgCount) {
194     Diags.Report(diag::err_drv_missing_argument)
195         << Args.getArgString(MissingArgIndex) << MissingArgCount;
196     Success = false;
197   }
198 
199   // Issue errors on unknown arguments.
200   for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {
201     auto ArgString = A->getAsString(Args);
202     std::string Nearest;
203     if (OptTbl.findNearest(ArgString, Nearest, IncludedFlagsBitmask) > 1)
204       Diags.Report(diag::err_drv_unknown_argument) << ArgString;
205     else
206       Diags.Report(diag::err_drv_unknown_argument_with_suggestion)
207           << ArgString << Nearest;
208     Success = false;
209   }
210 
211   // Construct the invocation.
212 
213   // Target Options
214   Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
215   if (Arg *A = Args.getLastArg(options::OPT_darwin_target_variant_triple))
216     Opts.DarwinTargetVariantTriple = llvm::Triple(A->getValue());
217 
218   Opts.CPU = std::string(Args.getLastArgValue(OPT_target_cpu));
219   Opts.Features = Args.getAllArgValues(OPT_target_feature);
220 
221   // Use the default target triple if unspecified.
222   if (Opts.Triple.empty())
223     Opts.Triple = llvm::sys::getDefaultTargetTriple();
224 
225   // Language Options
226   Opts.IncludePaths = Args.getAllArgValues(OPT_I);
227   Opts.NoInitialTextSection = Args.hasArg(OPT_n);
228   Opts.SaveTemporaryLabels = Args.hasArg(OPT_msave_temp_labels);
229   // Any DebugInfoKind implies GenDwarfForAssembly.
230   Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);
231 
232   if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections_EQ)) {
233     Opts.CompressDebugSections =
234         llvm::StringSwitch<llvm::DebugCompressionType>(A->getValue())
235             .Case("none", llvm::DebugCompressionType::None)
236             .Case("zlib", llvm::DebugCompressionType::Z)
237             .Default(llvm::DebugCompressionType::None);
238   }
239 
240   Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);
241   if (auto *DwarfFormatArg = Args.getLastArg(OPT_gdwarf64, OPT_gdwarf32))
242     Opts.Dwarf64 = DwarfFormatArg->getOption().matches(OPT_gdwarf64);
243   Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);
244   Opts.DwarfDebugFlags =
245       std::string(Args.getLastArgValue(OPT_dwarf_debug_flags));
246   Opts.DwarfDebugProducer =
247       std::string(Args.getLastArgValue(OPT_dwarf_debug_producer));
248   if (const Arg *A = Args.getLastArg(options::OPT_ffile_compilation_dir_EQ,
249                                      options::OPT_fdebug_compilation_dir_EQ))
250     Opts.DebugCompilationDir = A->getValue();
251   Opts.MainFileName = std::string(Args.getLastArgValue(OPT_main_file_name));
252 
253   for (const auto &Arg : Args.getAllArgValues(OPT_fdebug_prefix_map_EQ)) {
254     auto Split = StringRef(Arg).split('=');
255     Opts.DebugPrefixMap.insert(
256         {std::string(Split.first), std::string(Split.second)});
257   }
258 
259   // Frontend Options
260   if (Args.hasArg(OPT_INPUT)) {
261     bool First = true;
262     for (const Arg *A : Args.filtered(OPT_INPUT)) {
263       if (First) {
264         Opts.InputFile = A->getValue();
265         First = false;
266       } else {
267         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
268         Success = false;
269       }
270     }
271   }
272   Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
273   Opts.OutputPath = std::string(Args.getLastArgValue(OPT_o));
274   Opts.SplitDwarfOutput =
275       std::string(Args.getLastArgValue(OPT_split_dwarf_output));
276   if (Arg *A = Args.getLastArg(OPT_filetype)) {
277     StringRef Name = A->getValue();
278     unsigned OutputType = StringSwitch<unsigned>(Name)
279       .Case("asm", FT_Asm)
280       .Case("null", FT_Null)
281       .Case("obj", FT_Obj)
282       .Default(~0U);
283     if (OutputType == ~0U) {
284       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
285       Success = false;
286     } else
287       Opts.OutputType = FileType(OutputType);
288   }
289   Opts.ShowHelp = Args.hasArg(OPT_help);
290   Opts.ShowVersion = Args.hasArg(OPT_version);
291 
292   // Transliterate Options
293   Opts.OutputAsmVariant =
294       getLastArgIntValue(Args, OPT_output_asm_variant, 0, Diags);
295   Opts.ShowEncoding = Args.hasArg(OPT_show_encoding);
296   Opts.ShowInst = Args.hasArg(OPT_show_inst);
297 
298   // Assemble Options
299   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
300   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
301   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
302   Opts.NoWarn = Args.hasArg(OPT_massembler_no_warn);
303   Opts.RelocationModel =
304       std::string(Args.getLastArgValue(OPT_mrelocation_model, "pic"));
305   Opts.TargetABI = std::string(Args.getLastArgValue(OPT_target_abi));
306   Opts.IncrementalLinkerCompatible =
307       Args.hasArg(OPT_mincremental_linker_compatible);
308   Opts.SymbolDefs = Args.getAllArgValues(OPT_defsym);
309 
310   // EmbedBitcode Option. If -fembed-bitcode is enabled, set the flag.
311   // EmbedBitcode behaves the same for all embed options for assembly files.
312   if (auto *A = Args.getLastArg(OPT_fembed_bitcode_EQ)) {
313     Opts.EmbedBitcode = llvm::StringSwitch<unsigned>(A->getValue())
314                             .Case("all", 1)
315                             .Case("bitcode", 1)
316                             .Case("marker", 1)
317                             .Default(0);
318   }
319 
320   return Success;
321 }
322 
323 static std::unique_ptr<raw_fd_ostream>
324 getOutputStream(StringRef Path, DiagnosticsEngine &Diags, bool Binary) {
325   // Make sure that the Out file gets unlinked from the disk if we get a
326   // SIGINT.
327   if (Path != "-")
328     sys::RemoveFileOnSignal(Path);
329 
330   std::error_code EC;
331   auto Out = std::make_unique<raw_fd_ostream>(
332       Path, EC, (Binary ? sys::fs::OF_None : sys::fs::OF_TextWithCRLF));
333   if (EC) {
334     Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
335     return nullptr;
336   }
337 
338   return Out;
339 }
340 
341 static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
342                                  DiagnosticsEngine &Diags) {
343   // Get the target specific parser.
344   std::string Error;
345   const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
346   if (!TheTarget)
347     return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
348 
349   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
350       MemoryBuffer::getFileOrSTDIN(Opts.InputFile, /*IsText=*/true);
351 
352   if (std::error_code EC = Buffer.getError()) {
353     Error = EC.message();
354     return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
355   }
356 
357   SourceMgr SrcMgr;
358 
359   // Tell SrcMgr about this buffer, which is what the parser will pick up.
360   unsigned BufferIndex = SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
361 
362   // Record the location of the include directories so that the lexer can find
363   // it later.
364   SrcMgr.setIncludeDirs(Opts.IncludePaths);
365 
366   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
367   assert(MRI && "Unable to create target register info!");
368 
369   MCTargetOptions MCOptions;
370   std::unique_ptr<MCAsmInfo> MAI(
371       TheTarget->createMCAsmInfo(*MRI, Opts.Triple, MCOptions));
372   assert(MAI && "Unable to create target asm info!");
373 
374   // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
375   // may be created with a combination of default and explicit settings.
376   MAI->setCompressDebugSections(Opts.CompressDebugSections);
377 
378   MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);
379 
380   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
381   if (Opts.OutputPath.empty())
382     Opts.OutputPath = "-";
383   std::unique_ptr<raw_fd_ostream> FDOS =
384       getOutputStream(Opts.OutputPath, Diags, IsBinary);
385   if (!FDOS)
386     return true;
387   std::unique_ptr<raw_fd_ostream> DwoOS;
388   if (!Opts.SplitDwarfOutput.empty())
389     DwoOS = getOutputStream(Opts.SplitDwarfOutput, Diags, IsBinary);
390 
391   // Build up the feature string from the target feature list.
392   std::string FS = llvm::join(Opts.Features, ",");
393 
394   std::unique_ptr<MCSubtargetInfo> STI(
395       TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
396   assert(STI && "Unable to create subtarget info!");
397 
398   MCContext Ctx(Triple(Opts.Triple), MAI.get(), MRI.get(), STI.get(), &SrcMgr,
399                 &MCOptions);
400 
401   bool PIC = false;
402   if (Opts.RelocationModel == "static") {
403     PIC = false;
404   } else if (Opts.RelocationModel == "pic") {
405     PIC = true;
406   } else {
407     assert(Opts.RelocationModel == "dynamic-no-pic" &&
408            "Invalid PIC model!");
409     PIC = false;
410   }
411 
412   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
413   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
414   std::unique_ptr<MCObjectFileInfo> MOFI(
415       TheTarget->createMCObjectFileInfo(Ctx, PIC));
416   if (Opts.DarwinTargetVariantTriple)
417     MOFI->setDarwinTargetVariantTriple(*Opts.DarwinTargetVariantTriple);
418   Ctx.setObjectFileInfo(MOFI.get());
419 
420   if (Opts.SaveTemporaryLabels)
421     Ctx.setAllowTemporaryLabels(false);
422   if (Opts.GenDwarfForAssembly)
423     Ctx.setGenDwarfForAssembly(true);
424   if (!Opts.DwarfDebugFlags.empty())
425     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
426   if (!Opts.DwarfDebugProducer.empty())
427     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
428   if (!Opts.DebugCompilationDir.empty())
429     Ctx.setCompilationDir(Opts.DebugCompilationDir);
430   else {
431     // If no compilation dir is set, try to use the current directory.
432     SmallString<128> CWD;
433     if (!sys::fs::current_path(CWD))
434       Ctx.setCompilationDir(CWD);
435   }
436   if (!Opts.DebugPrefixMap.empty())
437     for (const auto &KV : Opts.DebugPrefixMap)
438       Ctx.addDebugPrefixMapEntry(KV.first, KV.second);
439   if (!Opts.MainFileName.empty())
440     Ctx.setMainFileName(StringRef(Opts.MainFileName));
441   Ctx.setDwarfFormat(Opts.Dwarf64 ? dwarf::DWARF64 : dwarf::DWARF32);
442   Ctx.setDwarfVersion(Opts.DwarfVersion);
443   if (Opts.GenDwarfForAssembly)
444     Ctx.setGenDwarfRootFile(Opts.InputFile,
445                             SrcMgr.getMemoryBuffer(BufferIndex)->getBuffer());
446 
447   std::unique_ptr<MCStreamer> Str;
448 
449   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
450   assert(MCII && "Unable to create instruction info!");
451 
452   raw_pwrite_stream *Out = FDOS.get();
453   std::unique_ptr<buffer_ostream> BOS;
454 
455   MCOptions.MCNoWarn = Opts.NoWarn;
456   MCOptions.MCFatalWarnings = Opts.FatalWarnings;
457   MCOptions.ABIName = Opts.TargetABI;
458 
459   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
460   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
461     MCInstPrinter *IP = TheTarget->createMCInstPrinter(
462         llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
463 
464     std::unique_ptr<MCCodeEmitter> CE;
465     if (Opts.ShowEncoding)
466       CE.reset(TheTarget->createMCCodeEmitter(*MCII, Ctx));
467     std::unique_ptr<MCAsmBackend> MAB(
468         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
469 
470     auto FOut = std::make_unique<formatted_raw_ostream>(*Out);
471     Str.reset(TheTarget->createAsmStreamer(
472         Ctx, std::move(FOut), /*asmverbose*/ true,
473         /*useDwarfDirectory*/ true, IP, std::move(CE), std::move(MAB),
474         Opts.ShowInst));
475   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
476     Str.reset(createNullStreamer(Ctx));
477   } else {
478     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
479            "Invalid file type!");
480     if (!FDOS->supportsSeeking()) {
481       BOS = std::make_unique<buffer_ostream>(*FDOS);
482       Out = BOS.get();
483     }
484 
485     std::unique_ptr<MCCodeEmitter> CE(
486         TheTarget->createMCCodeEmitter(*MCII, Ctx));
487     std::unique_ptr<MCAsmBackend> MAB(
488         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
489     assert(MAB && "Unable to create asm backend!");
490 
491     std::unique_ptr<MCObjectWriter> OW =
492         DwoOS ? MAB->createDwoObjectWriter(*Out, *DwoOS)
493               : MAB->createObjectWriter(*Out);
494 
495     Triple T(Opts.Triple);
496     Str.reset(TheTarget->createMCObjectStreamer(
497         T, Ctx, std::move(MAB), std::move(OW), std::move(CE), *STI,
498         Opts.RelaxAll, Opts.IncrementalLinkerCompatible,
499         /*DWARFMustBeAtTheEnd*/ true));
500     Str.get()->initSections(Opts.NoExecStack, *STI);
501   }
502 
503   // When -fembed-bitcode is passed to clang_as, a 1-byte marker
504   // is emitted in __LLVM,__asm section if the object file is MachO format.
505   if (Opts.EmbedBitcode && Ctx.getObjectFileType() == MCContext::IsMachO) {
506     MCSection *AsmLabel = Ctx.getMachOSection(
507         "__LLVM", "__asm", MachO::S_REGULAR, 4, SectionKind::getReadOnly());
508     Str.get()->SwitchSection(AsmLabel);
509     Str.get()->emitZeros(1);
510   }
511 
512   // Assembly to object compilation should leverage assembly info.
513   Str->setUseAssemblerInfoForParsing(true);
514 
515   bool Failed = false;
516 
517   std::unique_ptr<MCAsmParser> Parser(
518       createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
519 
520   // FIXME: init MCTargetOptions from sanitizer flags here.
521   std::unique_ptr<MCTargetAsmParser> TAP(
522       TheTarget->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
523   if (!TAP)
524     Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
525 
526   // Set values for symbols, if any.
527   for (auto &S : Opts.SymbolDefs) {
528     auto Pair = StringRef(S).split('=');
529     auto Sym = Pair.first;
530     auto Val = Pair.second;
531     int64_t Value;
532     // We have already error checked this in the driver.
533     Val.getAsInteger(0, Value);
534     Ctx.setSymbolValue(Parser->getStreamer(), Sym, Value);
535   }
536 
537   if (!Failed) {
538     Parser->setTargetParser(*TAP.get());
539     Failed = Parser->Run(Opts.NoInitialTextSection);
540   }
541 
542   return Failed;
543 }
544 
545 static bool ExecuteAssembler(AssemblerInvocation &Opts,
546                              DiagnosticsEngine &Diags) {
547   bool Failed = ExecuteAssemblerImpl(Opts, Diags);
548 
549   // Delete output file if there were errors.
550   if (Failed) {
551     if (Opts.OutputPath != "-")
552       sys::fs::remove(Opts.OutputPath);
553     if (!Opts.SplitDwarfOutput.empty() && Opts.SplitDwarfOutput != "-")
554       sys::fs::remove(Opts.SplitDwarfOutput);
555   }
556 
557   return Failed;
558 }
559 
560 static void LLVMErrorHandler(void *UserData, const char *Message,
561                              bool GenCrashDiag) {
562   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
563 
564   Diags.Report(diag::err_fe_error_backend) << Message;
565 
566   // We cannot recover from llvm errors.
567   sys::Process::Exit(1);
568 }
569 
570 int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
571   // Initialize targets and assembly printers/parsers.
572   InitializeAllTargetInfos();
573   InitializeAllTargetMCs();
574   InitializeAllAsmParsers();
575 
576   // Construct our diagnostic client.
577   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
578   TextDiagnosticPrinter *DiagClient
579     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
580   DiagClient->setPrefix("clang -cc1as");
581   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
582   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
583 
584   // Set an error handler, so that any LLVM backend diagnostics go through our
585   // error handler.
586   ScopedFatalErrorHandler FatalErrorHandler
587     (LLVMErrorHandler, static_cast<void*>(&Diags));
588 
589   // Parse the arguments.
590   AssemblerInvocation Asm;
591   if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
592     return 1;
593 
594   if (Asm.ShowHelp) {
595     getDriverOptTable().printHelp(
596         llvm::outs(), "clang -cc1as [options] file...",
597         "Clang Integrated Assembler",
598         /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0,
599         /*ShowAllAliases=*/false);
600     return 0;
601   }
602 
603   // Honor -version.
604   //
605   // FIXME: Use a better -version message?
606   if (Asm.ShowVersion) {
607     llvm::cl::PrintVersionMessage();
608     return 0;
609   }
610 
611   // Honor -mllvm.
612   //
613   // FIXME: Remove this, one day.
614   if (!Asm.LLVMArgs.empty()) {
615     unsigned NumArgs = Asm.LLVMArgs.size();
616     auto Args = std::make_unique<const char*[]>(NumArgs + 2);
617     Args[0] = "clang (LLVM option parsing)";
618     for (unsigned i = 0; i != NumArgs; ++i)
619       Args[i + 1] = Asm.LLVMArgs[i].c_str();
620     Args[NumArgs + 1] = nullptr;
621     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());
622   }
623 
624   // Execute the invocation, unless there were parsing errors.
625   bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
626 
627   // If any timers were active but haven't been destroyed yet, print their
628   // results now.
629   TimerGroup::printAll(errs());
630   TimerGroup::clearAll();
631 
632   return !!Failed;
633 }
634