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 <optional>
58 #include <system_error>
59 using namespace clang;
60 using namespace clang::driver;
61 using namespace clang::driver::options;
62 using namespace llvm;
63 using namespace llvm::opt;
64 
65 namespace {
66 
67 /// Helper class for representing a single invocation of the assembler.
68 struct AssemblerInvocation {
69   /// @name Target Options
70   /// @{
71 
72   /// The name of the target triple to assemble for.
73   std::string Triple;
74 
75   /// If given, the name of the target CPU to determine which instructions
76   /// are legal.
77   std::string CPU;
78 
79   /// The list of target specific features to enable or disable -- this should
80   /// be a list of strings starting with '+' or '-'.
81   std::vector<std::string> Features;
82 
83   /// The list of symbol definitions.
84   std::vector<std::string> SymbolDefs;
85 
86   /// @}
87   /// @name Language Options
88   /// @{
89 
90   std::vector<std::string> IncludePaths;
91   unsigned NoInitialTextSection : 1;
92   unsigned SaveTemporaryLabels : 1;
93   unsigned GenDwarfForAssembly : 1;
94   unsigned RelaxELFRelocations : 1;
95   unsigned Dwarf64 : 1;
96   unsigned DwarfVersion;
97   std::string DwarfDebugFlags;
98   std::string DwarfDebugProducer;
99   std::string DebugCompilationDir;
100   std::map<const std::string, const std::string> DebugPrefixMap;
101   llvm::DebugCompressionType CompressDebugSections =
102       llvm::DebugCompressionType::None;
103   std::string MainFileName;
104   std::string SplitDwarfOutput;
105 
106   /// @}
107   /// @name Frontend Options
108   /// @{
109 
110   std::string InputFile;
111   std::vector<std::string> LLVMArgs;
112   std::string OutputPath;
113   enum FileType {
114     FT_Asm,  ///< Assembly (.s) output, transliterate mode.
115     FT_Null, ///< No output, for timing purposes.
116     FT_Obj   ///< Object file output.
117   };
118   FileType OutputType;
119   unsigned ShowHelp : 1;
120   unsigned ShowVersion : 1;
121 
122   /// @}
123   /// @name Transliterate Options
124   /// @{
125 
126   unsigned OutputAsmVariant;
127   unsigned ShowEncoding : 1;
128   unsigned ShowInst : 1;
129 
130   /// @}
131   /// @name Assembler Options
132   /// @{
133 
134   unsigned RelaxAll : 1;
135   unsigned NoExecStack : 1;
136   unsigned FatalWarnings : 1;
137   unsigned NoWarn : 1;
138   unsigned NoTypeCheck : 1;
139   unsigned IncrementalLinkerCompatible : 1;
140   unsigned EmbedBitcode : 1;
141 
142   /// Whether to emit DWARF unwind info.
143   EmitDwarfUnwindType EmitDwarfUnwind;
144 
145   /// The name of the relocation model to use.
146   std::string RelocationModel;
147 
148   /// The ABI targeted by the backend. Specified using -target-abi. Empty
149   /// otherwise.
150   std::string TargetABI;
151 
152   /// Darwin target variant triple, the variant of the deployment target
153   /// for which the code is being compiled.
154   std::optional<llvm::Triple> DarwinTargetVariantTriple;
155 
156   /// The version of the darwin target variant SDK which was used during the
157   /// compilation
158   llvm::VersionTuple DarwinTargetVariantSDKVersion;
159 
160   /// The name of a file to use with \c .secure_log_unique directives.
161   std::string AsSecureLogFile;
162   /// @}
163 
164 public:
AssemblerInvocation__anon88d1df2b0111::AssemblerInvocation165   AssemblerInvocation() {
166     Triple = "";
167     NoInitialTextSection = 0;
168     InputFile = "-";
169     OutputPath = "-";
170     OutputType = FT_Asm;
171     OutputAsmVariant = 0;
172     ShowInst = 0;
173     ShowEncoding = 0;
174     RelaxAll = 0;
175     NoExecStack = 0;
176     FatalWarnings = 0;
177     NoWarn = 0;
178     NoTypeCheck = 0;
179     IncrementalLinkerCompatible = 0;
180     Dwarf64 = 0;
181     DwarfVersion = 0;
182     EmbedBitcode = 0;
183     EmitDwarfUnwind = EmitDwarfUnwindType::Default;
184   }
185 
186   static bool CreateFromArgs(AssemblerInvocation &Res,
187                              ArrayRef<const char *> Argv,
188                              DiagnosticsEngine &Diags);
189 };
190 
191 }
192 
CreateFromArgs(AssemblerInvocation & Opts,ArrayRef<const char * > Argv,DiagnosticsEngine & Diags)193 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
194                                          ArrayRef<const char *> Argv,
195                                          DiagnosticsEngine &Diags) {
196   bool Success = true;
197 
198   // Parse the arguments.
199   const OptTable &OptTbl = getDriverOptTable();
200 
201   const unsigned IncludedFlagsBitmask = options::CC1AsOption;
202   unsigned MissingArgIndex, MissingArgCount;
203   InputArgList Args = OptTbl.ParseArgs(Argv, MissingArgIndex, MissingArgCount,
204                                        IncludedFlagsBitmask);
205 
206   // Check for missing argument error.
207   if (MissingArgCount) {
208     Diags.Report(diag::err_drv_missing_argument)
209         << Args.getArgString(MissingArgIndex) << MissingArgCount;
210     Success = false;
211   }
212 
213   // Issue errors on unknown arguments.
214   for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {
215     auto ArgString = A->getAsString(Args);
216     std::string Nearest;
217     if (OptTbl.findNearest(ArgString, Nearest, IncludedFlagsBitmask) > 1)
218       Diags.Report(diag::err_drv_unknown_argument) << ArgString;
219     else
220       Diags.Report(diag::err_drv_unknown_argument_with_suggestion)
221           << ArgString << Nearest;
222     Success = false;
223   }
224 
225   // Construct the invocation.
226 
227   // Target Options
228   Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
229   if (Arg *A = Args.getLastArg(options::OPT_darwin_target_variant_triple))
230     Opts.DarwinTargetVariantTriple = llvm::Triple(A->getValue());
231   if (Arg *A = Args.getLastArg(OPT_darwin_target_variant_sdk_version_EQ)) {
232     VersionTuple Version;
233     if (Version.tryParse(A->getValue()))
234       Diags.Report(diag::err_drv_invalid_value)
235           << A->getAsString(Args) << A->getValue();
236     else
237       Opts.DarwinTargetVariantSDKVersion = Version;
238   }
239 
240   Opts.CPU = std::string(Args.getLastArgValue(OPT_target_cpu));
241   Opts.Features = Args.getAllArgValues(OPT_target_feature);
242 
243   // Use the default target triple if unspecified.
244   if (Opts.Triple.empty())
245     Opts.Triple = llvm::sys::getDefaultTargetTriple();
246 
247   // Language Options
248   Opts.IncludePaths = Args.getAllArgValues(OPT_I);
249   Opts.NoInitialTextSection = Args.hasArg(OPT_n);
250   Opts.SaveTemporaryLabels = Args.hasArg(OPT_msave_temp_labels);
251   // Any DebugInfoKind implies GenDwarfForAssembly.
252   Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);
253 
254   if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections_EQ)) {
255     Opts.CompressDebugSections =
256         llvm::StringSwitch<llvm::DebugCompressionType>(A->getValue())
257             .Case("none", llvm::DebugCompressionType::None)
258             .Case("zlib", llvm::DebugCompressionType::Zlib)
259             .Case("zstd", llvm::DebugCompressionType::Zstd)
260             .Default(llvm::DebugCompressionType::None);
261   }
262 
263   Opts.RelaxELFRelocations = !Args.hasArg(OPT_mrelax_relocations_no);
264   if (auto *DwarfFormatArg = Args.getLastArg(OPT_gdwarf64, OPT_gdwarf32))
265     Opts.Dwarf64 = DwarfFormatArg->getOption().matches(OPT_gdwarf64);
266   Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);
267   Opts.DwarfDebugFlags =
268       std::string(Args.getLastArgValue(OPT_dwarf_debug_flags));
269   Opts.DwarfDebugProducer =
270       std::string(Args.getLastArgValue(OPT_dwarf_debug_producer));
271   if (const Arg *A = Args.getLastArg(options::OPT_ffile_compilation_dir_EQ,
272                                      options::OPT_fdebug_compilation_dir_EQ))
273     Opts.DebugCompilationDir = A->getValue();
274   Opts.MainFileName = std::string(Args.getLastArgValue(OPT_main_file_name));
275 
276   for (const auto &Arg : Args.getAllArgValues(OPT_fdebug_prefix_map_EQ)) {
277     auto Split = StringRef(Arg).split('=');
278     Opts.DebugPrefixMap.insert(
279         {std::string(Split.first), std::string(Split.second)});
280   }
281 
282   // Frontend Options
283   if (Args.hasArg(OPT_INPUT)) {
284     bool First = true;
285     for (const Arg *A : Args.filtered(OPT_INPUT)) {
286       if (First) {
287         Opts.InputFile = A->getValue();
288         First = false;
289       } else {
290         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
291         Success = false;
292       }
293     }
294   }
295   Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
296   Opts.OutputPath = std::string(Args.getLastArgValue(OPT_o));
297   Opts.SplitDwarfOutput =
298       std::string(Args.getLastArgValue(OPT_split_dwarf_output));
299   if (Arg *A = Args.getLastArg(OPT_filetype)) {
300     StringRef Name = A->getValue();
301     unsigned OutputType = StringSwitch<unsigned>(Name)
302       .Case("asm", FT_Asm)
303       .Case("null", FT_Null)
304       .Case("obj", FT_Obj)
305       .Default(~0U);
306     if (OutputType == ~0U) {
307       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
308       Success = false;
309     } else
310       Opts.OutputType = FileType(OutputType);
311   }
312   Opts.ShowHelp = Args.hasArg(OPT_help);
313   Opts.ShowVersion = Args.hasArg(OPT_version);
314 
315   // Transliterate Options
316   Opts.OutputAsmVariant =
317       getLastArgIntValue(Args, OPT_output_asm_variant, 0, Diags);
318   Opts.ShowEncoding = Args.hasArg(OPT_show_encoding);
319   Opts.ShowInst = Args.hasArg(OPT_show_inst);
320 
321   // Assemble Options
322   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
323   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
324   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
325   Opts.NoWarn = Args.hasArg(OPT_massembler_no_warn);
326   Opts.NoTypeCheck = Args.hasArg(OPT_mno_type_check);
327   Opts.RelocationModel =
328       std::string(Args.getLastArgValue(OPT_mrelocation_model, "pic"));
329   Opts.TargetABI = std::string(Args.getLastArgValue(OPT_target_abi));
330   Opts.IncrementalLinkerCompatible =
331       Args.hasArg(OPT_mincremental_linker_compatible);
332   Opts.SymbolDefs = Args.getAllArgValues(OPT_defsym);
333 
334   // EmbedBitcode Option. If -fembed-bitcode is enabled, set the flag.
335   // EmbedBitcode behaves the same for all embed options for assembly files.
336   if (auto *A = Args.getLastArg(OPT_fembed_bitcode_EQ)) {
337     Opts.EmbedBitcode = llvm::StringSwitch<unsigned>(A->getValue())
338                             .Case("all", 1)
339                             .Case("bitcode", 1)
340                             .Case("marker", 1)
341                             .Default(0);
342   }
343 
344   if (auto *A = Args.getLastArg(OPT_femit_dwarf_unwind_EQ)) {
345     Opts.EmitDwarfUnwind =
346         llvm::StringSwitch<EmitDwarfUnwindType>(A->getValue())
347             .Case("always", EmitDwarfUnwindType::Always)
348             .Case("no-compact-unwind", EmitDwarfUnwindType::NoCompactUnwind)
349             .Case("default", EmitDwarfUnwindType::Default);
350   }
351 
352   Opts.AsSecureLogFile = Args.getLastArgValue(OPT_as_secure_log_file);
353 
354   return Success;
355 }
356 
357 static std::unique_ptr<raw_fd_ostream>
getOutputStream(StringRef Path,DiagnosticsEngine & Diags,bool Binary)358 getOutputStream(StringRef Path, DiagnosticsEngine &Diags, bool Binary) {
359   // Make sure that the Out file gets unlinked from the disk if we get a
360   // SIGINT.
361   if (Path != "-")
362     sys::RemoveFileOnSignal(Path);
363 
364   std::error_code EC;
365   auto Out = std::make_unique<raw_fd_ostream>(
366       Path, EC, (Binary ? sys::fs::OF_None : sys::fs::OF_TextWithCRLF));
367   if (EC) {
368     Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
369     return nullptr;
370   }
371 
372   return Out;
373 }
374 
ExecuteAssemblerImpl(AssemblerInvocation & Opts,DiagnosticsEngine & Diags)375 static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
376                                  DiagnosticsEngine &Diags) {
377   // Get the target specific parser.
378   std::string Error;
379   const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
380   if (!TheTarget)
381     return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
382 
383   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
384       MemoryBuffer::getFileOrSTDIN(Opts.InputFile, /*IsText=*/true);
385 
386   if (std::error_code EC = Buffer.getError()) {
387     Error = EC.message();
388     return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
389   }
390 
391   SourceMgr SrcMgr;
392 
393   // Tell SrcMgr about this buffer, which is what the parser will pick up.
394   unsigned BufferIndex = SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
395 
396   // Record the location of the include directories so that the lexer can find
397   // it later.
398   SrcMgr.setIncludeDirs(Opts.IncludePaths);
399 
400   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
401   assert(MRI && "Unable to create target register info!");
402 
403   MCTargetOptions MCOptions;
404   MCOptions.EmitDwarfUnwind = Opts.EmitDwarfUnwind;
405   MCOptions.AsSecureLogFile = Opts.AsSecureLogFile;
406 
407   std::unique_ptr<MCAsmInfo> MAI(
408       TheTarget->createMCAsmInfo(*MRI, Opts.Triple, MCOptions));
409   assert(MAI && "Unable to create target asm info!");
410 
411   // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
412   // may be created with a combination of default and explicit settings.
413   MAI->setCompressDebugSections(Opts.CompressDebugSections);
414 
415   MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);
416 
417   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
418   if (Opts.OutputPath.empty())
419     Opts.OutputPath = "-";
420   std::unique_ptr<raw_fd_ostream> FDOS =
421       getOutputStream(Opts.OutputPath, Diags, IsBinary);
422   if (!FDOS)
423     return true;
424   std::unique_ptr<raw_fd_ostream> DwoOS;
425   if (!Opts.SplitDwarfOutput.empty())
426     DwoOS = getOutputStream(Opts.SplitDwarfOutput, Diags, IsBinary);
427 
428   // Build up the feature string from the target feature list.
429   std::string FS = llvm::join(Opts.Features, ",");
430 
431   std::unique_ptr<MCSubtargetInfo> STI(
432       TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
433   assert(STI && "Unable to create subtarget info!");
434 
435   MCContext Ctx(Triple(Opts.Triple), MAI.get(), MRI.get(), STI.get(), &SrcMgr,
436                 &MCOptions);
437 
438   bool PIC = false;
439   if (Opts.RelocationModel == "static") {
440     PIC = false;
441   } else if (Opts.RelocationModel == "pic") {
442     PIC = true;
443   } else {
444     assert(Opts.RelocationModel == "dynamic-no-pic" &&
445            "Invalid PIC model!");
446     PIC = false;
447   }
448 
449   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
450   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
451   std::unique_ptr<MCObjectFileInfo> MOFI(
452       TheTarget->createMCObjectFileInfo(Ctx, PIC));
453   if (Opts.DarwinTargetVariantTriple)
454     MOFI->setDarwinTargetVariantTriple(*Opts.DarwinTargetVariantTriple);
455   if (!Opts.DarwinTargetVariantSDKVersion.empty())
456     MOFI->setDarwinTargetVariantSDKVersion(Opts.DarwinTargetVariantSDKVersion);
457   Ctx.setObjectFileInfo(MOFI.get());
458 
459   if (Opts.SaveTemporaryLabels)
460     Ctx.setAllowTemporaryLabels(false);
461   if (Opts.GenDwarfForAssembly)
462     Ctx.setGenDwarfForAssembly(true);
463   if (!Opts.DwarfDebugFlags.empty())
464     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
465   if (!Opts.DwarfDebugProducer.empty())
466     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
467   if (!Opts.DebugCompilationDir.empty())
468     Ctx.setCompilationDir(Opts.DebugCompilationDir);
469   else {
470     // If no compilation dir is set, try to use the current directory.
471     SmallString<128> CWD;
472     if (!sys::fs::current_path(CWD))
473       Ctx.setCompilationDir(CWD);
474   }
475   if (!Opts.DebugPrefixMap.empty())
476     for (const auto &KV : Opts.DebugPrefixMap)
477       Ctx.addDebugPrefixMapEntry(KV.first, KV.second);
478   if (!Opts.MainFileName.empty())
479     Ctx.setMainFileName(StringRef(Opts.MainFileName));
480   Ctx.setDwarfFormat(Opts.Dwarf64 ? dwarf::DWARF64 : dwarf::DWARF32);
481   Ctx.setDwarfVersion(Opts.DwarfVersion);
482   if (Opts.GenDwarfForAssembly)
483     Ctx.setGenDwarfRootFile(Opts.InputFile,
484                             SrcMgr.getMemoryBuffer(BufferIndex)->getBuffer());
485 
486   std::unique_ptr<MCStreamer> Str;
487 
488   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
489   assert(MCII && "Unable to create instruction info!");
490 
491   raw_pwrite_stream *Out = FDOS.get();
492   std::unique_ptr<buffer_ostream> BOS;
493 
494   MCOptions.MCNoWarn = Opts.NoWarn;
495   MCOptions.MCFatalWarnings = Opts.FatalWarnings;
496   MCOptions.MCNoTypeCheck = Opts.NoTypeCheck;
497   MCOptions.ABIName = Opts.TargetABI;
498 
499   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
500   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
501     MCInstPrinter *IP = TheTarget->createMCInstPrinter(
502         llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
503 
504     std::unique_ptr<MCCodeEmitter> CE;
505     if (Opts.ShowEncoding)
506       CE.reset(TheTarget->createMCCodeEmitter(*MCII, Ctx));
507     std::unique_ptr<MCAsmBackend> MAB(
508         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
509 
510     auto FOut = std::make_unique<formatted_raw_ostream>(*Out);
511     Str.reset(TheTarget->createAsmStreamer(
512         Ctx, std::move(FOut), /*asmverbose*/ true,
513         /*useDwarfDirectory*/ true, IP, std::move(CE), std::move(MAB),
514         Opts.ShowInst));
515   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
516     Str.reset(createNullStreamer(Ctx));
517   } else {
518     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
519            "Invalid file type!");
520     if (!FDOS->supportsSeeking()) {
521       BOS = std::make_unique<buffer_ostream>(*FDOS);
522       Out = BOS.get();
523     }
524 
525     std::unique_ptr<MCCodeEmitter> CE(
526         TheTarget->createMCCodeEmitter(*MCII, Ctx));
527     std::unique_ptr<MCAsmBackend> MAB(
528         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
529     assert(MAB && "Unable to create asm backend!");
530 
531     std::unique_ptr<MCObjectWriter> OW =
532         DwoOS ? MAB->createDwoObjectWriter(*Out, *DwoOS)
533               : MAB->createObjectWriter(*Out);
534 
535     Triple T(Opts.Triple);
536     Str.reset(TheTarget->createMCObjectStreamer(
537         T, Ctx, std::move(MAB), std::move(OW), std::move(CE), *STI,
538         Opts.RelaxAll, Opts.IncrementalLinkerCompatible,
539         /*DWARFMustBeAtTheEnd*/ true));
540     Str.get()->initSections(Opts.NoExecStack, *STI);
541   }
542 
543   // When -fembed-bitcode is passed to clang_as, a 1-byte marker
544   // is emitted in __LLVM,__asm section if the object file is MachO format.
545   if (Opts.EmbedBitcode && Ctx.getObjectFileType() == MCContext::IsMachO) {
546     MCSection *AsmLabel = Ctx.getMachOSection(
547         "__LLVM", "__asm", MachO::S_REGULAR, 4, SectionKind::getReadOnly());
548     Str.get()->switchSection(AsmLabel);
549     Str.get()->emitZeros(1);
550   }
551 
552   // Assembly to object compilation should leverage assembly info.
553   Str->setUseAssemblerInfoForParsing(true);
554 
555   bool Failed = false;
556 
557   std::unique_ptr<MCAsmParser> Parser(
558       createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
559 
560   // FIXME: init MCTargetOptions from sanitizer flags here.
561   std::unique_ptr<MCTargetAsmParser> TAP(
562       TheTarget->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
563   if (!TAP)
564     Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
565 
566   // Set values for symbols, if any.
567   for (auto &S : Opts.SymbolDefs) {
568     auto Pair = StringRef(S).split('=');
569     auto Sym = Pair.first;
570     auto Val = Pair.second;
571     int64_t Value;
572     // We have already error checked this in the driver.
573     Val.getAsInteger(0, Value);
574     Ctx.setSymbolValue(Parser->getStreamer(), Sym, Value);
575   }
576 
577   if (!Failed) {
578     Parser->setTargetParser(*TAP.get());
579     Failed = Parser->Run(Opts.NoInitialTextSection);
580   }
581 
582   return Failed;
583 }
584 
ExecuteAssembler(AssemblerInvocation & Opts,DiagnosticsEngine & Diags)585 static bool ExecuteAssembler(AssemblerInvocation &Opts,
586                              DiagnosticsEngine &Diags) {
587   bool Failed = ExecuteAssemblerImpl(Opts, Diags);
588 
589   // Delete output file if there were errors.
590   if (Failed) {
591     if (Opts.OutputPath != "-")
592       sys::fs::remove(Opts.OutputPath);
593     if (!Opts.SplitDwarfOutput.empty() && Opts.SplitDwarfOutput != "-")
594       sys::fs::remove(Opts.SplitDwarfOutput);
595   }
596 
597   return Failed;
598 }
599 
LLVMErrorHandler(void * UserData,const char * Message,bool GenCrashDiag)600 static void LLVMErrorHandler(void *UserData, const char *Message,
601                              bool GenCrashDiag) {
602   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
603 
604   Diags.Report(diag::err_fe_error_backend) << Message;
605 
606   // We cannot recover from llvm errors.
607   sys::Process::Exit(1);
608 }
609 
cc1as_main(ArrayRef<const char * > Argv,const char * Argv0,void * MainAddr)610 int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
611   // Initialize targets and assembly printers/parsers.
612   InitializeAllTargetInfos();
613   InitializeAllTargetMCs();
614   InitializeAllAsmParsers();
615 
616   // Construct our diagnostic client.
617   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
618   TextDiagnosticPrinter *DiagClient
619     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
620   DiagClient->setPrefix("clang -cc1as");
621   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
622   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
623 
624   // Set an error handler, so that any LLVM backend diagnostics go through our
625   // error handler.
626   ScopedFatalErrorHandler FatalErrorHandler
627     (LLVMErrorHandler, static_cast<void*>(&Diags));
628 
629   // Parse the arguments.
630   AssemblerInvocation Asm;
631   if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
632     return 1;
633 
634   if (Asm.ShowHelp) {
635     getDriverOptTable().printHelp(
636         llvm::outs(), "clang -cc1as [options] file...",
637         "Clang Integrated Assembler",
638         /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0,
639         /*ShowAllAliases=*/false);
640     return 0;
641   }
642 
643   // Honor -version.
644   //
645   // FIXME: Use a better -version message?
646   if (Asm.ShowVersion) {
647     llvm::cl::PrintVersionMessage();
648     return 0;
649   }
650 
651   // Honor -mllvm.
652   //
653   // FIXME: Remove this, one day.
654   if (!Asm.LLVMArgs.empty()) {
655     unsigned NumArgs = Asm.LLVMArgs.size();
656     auto Args = std::make_unique<const char*[]>(NumArgs + 2);
657     Args[0] = "clang (LLVM option parsing)";
658     for (unsigned i = 0; i != NumArgs; ++i)
659       Args[i + 1] = Asm.LLVMArgs[i].c_str();
660     Args[NumArgs + 1] = nullptr;
661     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());
662   }
663 
664   // Execute the invocation, unless there were parsing errors.
665   bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
666 
667   // If any timers were active but haven't been destroyed yet, print their
668   // results now.
669   TimerGroup::printAll(errs());
670   TimerGroup::clearAll();
671 
672   return !!Failed;
673 }
674