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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/MCParser/MCTargetAsmParser.h"
34 #include "llvm/MC/MCRegisterInfo.h"
35 #include "llvm/MC/MCStreamer.h"
36 #include "llvm/MC/MCSubtargetInfo.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/MemoryBuffer.h"
47 #include "llvm/Support/Path.h"
48 #include "llvm/Support/Signals.h"
49 #include "llvm/Support/SourceMgr.h"
50 #include "llvm/Support/TargetRegistry.h"
51 #include "llvm/Support/TargetSelect.h"
52 #include "llvm/Support/Timer.h"
53 #include "llvm/Support/raw_ostream.h"
54 #include <memory>
55 #include <system_error>
56 using namespace clang;
57 using namespace clang::driver;
58 using namespace clang::driver::options;
59 using namespace llvm;
60 using namespace llvm::opt;
61 
62 namespace {
63 
64 /// \brief Helper class for representing a single invocation of the assembler.
65 struct AssemblerInvocation {
66   /// @name Target Options
67   /// @{
68 
69   /// The name of the target triple to assemble for.
70   std::string Triple;
71 
72   /// If given, the name of the target CPU to determine which instructions
73   /// are legal.
74   std::string CPU;
75 
76   /// The list of target specific features to enable or disable -- this should
77   /// be a list of strings starting with '+' or '-'.
78   std::vector<std::string> Features;
79 
80   /// @}
81   /// @name Language Options
82   /// @{
83 
84   std::vector<std::string> IncludePaths;
85   unsigned NoInitialTextSection : 1;
86   unsigned SaveTemporaryLabels : 1;
87   unsigned GenDwarfForAssembly : 1;
88   unsigned CompressDebugSections : 1;
89   unsigned RelaxELFRelocations : 1;
90   unsigned DwarfVersion;
91   std::string DwarfDebugFlags;
92   std::string DwarfDebugProducer;
93   std::string DebugCompilationDir;
94   std::string MainFileName;
95 
96   /// @}
97   /// @name Frontend Options
98   /// @{
99 
100   std::string InputFile;
101   std::vector<std::string> LLVMArgs;
102   std::string OutputPath;
103   enum FileType {
104     FT_Asm,  ///< Assembly (.s) output, transliterate mode.
105     FT_Null, ///< No output, for timing purposes.
106     FT_Obj   ///< Object file output.
107   };
108   FileType OutputType;
109   unsigned ShowHelp : 1;
110   unsigned ShowVersion : 1;
111 
112   /// @}
113   /// @name Transliterate Options
114   /// @{
115 
116   unsigned OutputAsmVariant;
117   unsigned ShowEncoding : 1;
118   unsigned ShowInst : 1;
119 
120   /// @}
121   /// @name Assembler Options
122   /// @{
123 
124   unsigned RelaxAll : 1;
125   unsigned NoExecStack : 1;
126   unsigned FatalWarnings : 1;
127   unsigned IncrementalLinkerCompatible : 1;
128 
129   /// The name of the relocation model to use.
130   std::string RelocationModel;
131 
132   /// @}
133 
134 public:
AssemblerInvocation__anon60660f7d0111::AssemblerInvocation135   AssemblerInvocation() {
136     Triple = "";
137     NoInitialTextSection = 0;
138     InputFile = "-";
139     OutputPath = "-";
140     OutputType = FT_Asm;
141     OutputAsmVariant = 0;
142     ShowInst = 0;
143     ShowEncoding = 0;
144     RelaxAll = 0;
145     NoExecStack = 0;
146     FatalWarnings = 0;
147     IncrementalLinkerCompatible = 0;
148     DwarfVersion = 0;
149   }
150 
151   static bool CreateFromArgs(AssemblerInvocation &Res,
152                              ArrayRef<const char *> Argv,
153                              DiagnosticsEngine &Diags);
154 };
155 
156 }
157 
CreateFromArgs(AssemblerInvocation & Opts,ArrayRef<const char * > Argv,DiagnosticsEngine & Diags)158 bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
159                                          ArrayRef<const char *> Argv,
160                                          DiagnosticsEngine &Diags) {
161   bool Success = true;
162 
163   // Parse the arguments.
164   std::unique_ptr<OptTable> OptTbl(createDriverOptTable());
165 
166   const unsigned IncludedFlagsBitmask = options::CC1AsOption;
167   unsigned MissingArgIndex, MissingArgCount;
168   InputArgList Args = OptTbl->ParseArgs(Argv, MissingArgIndex, MissingArgCount,
169                                         IncludedFlagsBitmask);
170 
171   // Check for missing argument error.
172   if (MissingArgCount) {
173     Diags.Report(diag::err_drv_missing_argument)
174         << Args.getArgString(MissingArgIndex) << MissingArgCount;
175     Success = false;
176   }
177 
178   // Issue errors on unknown arguments.
179   for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {
180     Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
181     Success = false;
182   }
183 
184   // Construct the invocation.
185 
186   // Target Options
187   Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
188   Opts.CPU = Args.getLastArgValue(OPT_target_cpu);
189   Opts.Features = Args.getAllArgValues(OPT_target_feature);
190 
191   // Use the default target triple if unspecified.
192   if (Opts.Triple.empty())
193     Opts.Triple = llvm::sys::getDefaultTargetTriple();
194 
195   // Language Options
196   Opts.IncludePaths = Args.getAllArgValues(OPT_I);
197   Opts.NoInitialTextSection = Args.hasArg(OPT_n);
198   Opts.SaveTemporaryLabels = Args.hasArg(OPT_msave_temp_labels);
199   // Any DebugInfoKind implies GenDwarfForAssembly.
200   Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);
201   Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
202   Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);
203   Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);
204   Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
205   Opts.DwarfDebugProducer = Args.getLastArgValue(OPT_dwarf_debug_producer);
206   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
207   Opts.MainFileName = Args.getLastArgValue(OPT_main_file_name);
208 
209   // Frontend Options
210   if (Args.hasArg(OPT_INPUT)) {
211     bool First = true;
212     for (arg_iterator it = Args.filtered_begin(OPT_INPUT),
213                       ie = Args.filtered_end();
214          it != ie; ++it, First = false) {
215       const Arg *A = it;
216       if (First)
217         Opts.InputFile = A->getValue();
218       else {
219         Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
220         Success = false;
221       }
222     }
223   }
224   Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
225   Opts.OutputPath = Args.getLastArgValue(OPT_o);
226   if (Arg *A = Args.getLastArg(OPT_filetype)) {
227     StringRef Name = A->getValue();
228     unsigned OutputType = StringSwitch<unsigned>(Name)
229       .Case("asm", FT_Asm)
230       .Case("null", FT_Null)
231       .Case("obj", FT_Obj)
232       .Default(~0U);
233     if (OutputType == ~0U) {
234       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
235       Success = false;
236     } else
237       Opts.OutputType = FileType(OutputType);
238   }
239   Opts.ShowHelp = Args.hasArg(OPT_help);
240   Opts.ShowVersion = Args.hasArg(OPT_version);
241 
242   // Transliterate Options
243   Opts.OutputAsmVariant =
244       getLastArgIntValue(Args, OPT_output_asm_variant, 0, Diags);
245   Opts.ShowEncoding = Args.hasArg(OPT_show_encoding);
246   Opts.ShowInst = Args.hasArg(OPT_show_inst);
247 
248   // Assemble Options
249   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
250   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
251   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
252   Opts.RelocationModel = Args.getLastArgValue(OPT_mrelocation_model, "pic");
253   Opts.IncrementalLinkerCompatible =
254       Args.hasArg(OPT_mincremental_linker_compatible);
255 
256   return Success;
257 }
258 
259 static std::unique_ptr<raw_fd_ostream>
getOutputStream(AssemblerInvocation & Opts,DiagnosticsEngine & Diags,bool Binary)260 getOutputStream(AssemblerInvocation &Opts, DiagnosticsEngine &Diags,
261                 bool Binary) {
262   if (Opts.OutputPath.empty())
263     Opts.OutputPath = "-";
264 
265   // Make sure that the Out file gets unlinked from the disk if we get a
266   // SIGINT.
267   if (Opts.OutputPath != "-")
268     sys::RemoveFileOnSignal(Opts.OutputPath);
269 
270   std::error_code EC;
271   auto Out = llvm::make_unique<raw_fd_ostream>(
272       Opts.OutputPath, EC, (Binary ? sys::fs::F_None : sys::fs::F_Text));
273   if (EC) {
274     Diags.Report(diag::err_fe_unable_to_open_output) << Opts.OutputPath
275                                                      << EC.message();
276     return nullptr;
277   }
278 
279   return Out;
280 }
281 
ExecuteAssembler(AssemblerInvocation & Opts,DiagnosticsEngine & Diags)282 static bool ExecuteAssembler(AssemblerInvocation &Opts,
283                              DiagnosticsEngine &Diags) {
284   // Get the target specific parser.
285   std::string Error;
286   const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
287   if (!TheTarget)
288     return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
289 
290   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
291       MemoryBuffer::getFileOrSTDIN(Opts.InputFile);
292 
293   if (std::error_code EC = Buffer.getError()) {
294     Error = EC.message();
295     return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
296   }
297 
298   SourceMgr SrcMgr;
299 
300   // Tell SrcMgr about this buffer, which is what the parser will pick up.
301   SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
302 
303   // Record the location of the include directories so that the lexer can find
304   // it later.
305   SrcMgr.setIncludeDirs(Opts.IncludePaths);
306 
307   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
308   assert(MRI && "Unable to create target register info!");
309 
310   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, Opts.Triple));
311   assert(MAI && "Unable to create target asm info!");
312 
313   // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
314   // may be created with a combination of default and explicit settings.
315   if (Opts.CompressDebugSections)
316     MAI->setCompressDebugSections(DebugCompressionType::DCT_ZlibGnu);
317 
318   MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);
319 
320   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
321   std::unique_ptr<raw_fd_ostream> FDOS = getOutputStream(Opts, Diags, IsBinary);
322   if (!FDOS)
323     return true;
324 
325   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
326   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
327   std::unique_ptr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
328 
329   MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &SrcMgr);
330 
331   bool PIC = false;
332   if (Opts.RelocationModel == "static") {
333     PIC = false;
334   } else if (Opts.RelocationModel == "pic") {
335     PIC = true;
336   } else {
337     assert(Opts.RelocationModel == "dynamic-no-pic" &&
338            "Invalid PIC model!");
339     PIC = false;
340   }
341 
342   MOFI->InitMCObjectFileInfo(Triple(Opts.Triple), PIC, CodeModel::Default, Ctx);
343   if (Opts.SaveTemporaryLabels)
344     Ctx.setAllowTemporaryLabels(false);
345   if (Opts.GenDwarfForAssembly)
346     Ctx.setGenDwarfForAssembly(true);
347   if (!Opts.DwarfDebugFlags.empty())
348     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
349   if (!Opts.DwarfDebugProducer.empty())
350     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
351   if (!Opts.DebugCompilationDir.empty())
352     Ctx.setCompilationDir(Opts.DebugCompilationDir);
353   if (!Opts.MainFileName.empty())
354     Ctx.setMainFileName(StringRef(Opts.MainFileName));
355   Ctx.setDwarfVersion(Opts.DwarfVersion);
356 
357   // Build up the feature string from the target feature list.
358   std::string FS;
359   if (!Opts.Features.empty()) {
360     FS = Opts.Features[0];
361     for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
362       FS += "," + Opts.Features[i];
363   }
364 
365   std::unique_ptr<MCStreamer> Str;
366 
367   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
368   std::unique_ptr<MCSubtargetInfo> STI(
369       TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
370 
371   raw_pwrite_stream *Out = FDOS.get();
372   std::unique_ptr<buffer_ostream> BOS;
373 
374   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
375   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
376     MCInstPrinter *IP = TheTarget->createMCInstPrinter(
377         llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
378     MCCodeEmitter *CE = nullptr;
379     MCAsmBackend *MAB = nullptr;
380     if (Opts.ShowEncoding) {
381       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
382       MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple, Opts.CPU);
383     }
384     auto FOut = llvm::make_unique<formatted_raw_ostream>(*Out);
385     Str.reset(TheTarget->createAsmStreamer(
386         Ctx, std::move(FOut), /*asmverbose*/ true,
387         /*useDwarfDirectory*/ true, IP, CE, MAB, Opts.ShowInst));
388   } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
389     Str.reset(createNullStreamer(Ctx));
390   } else {
391     assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
392            "Invalid file type!");
393     if (!FDOS->supportsSeeking()) {
394       BOS = make_unique<buffer_ostream>(*FDOS);
395       Out = BOS.get();
396     }
397 
398     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
399     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple,
400                                                       Opts.CPU);
401     Triple T(Opts.Triple);
402     Str.reset(TheTarget->createMCObjectStreamer(
403         T, Ctx, *MAB, *Out, CE, *STI, Opts.RelaxAll,
404         Opts.IncrementalLinkerCompatible,
405         /*DWARFMustBeAtTheEnd*/ true));
406     Str.get()->InitSections(Opts.NoExecStack);
407   }
408 
409   bool Failed = false;
410 
411   std::unique_ptr<MCAsmParser> Parser(
412       createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
413 
414   // FIXME: init MCTargetOptions from sanitizer flags here.
415   MCTargetOptions Options;
416   std::unique_ptr<MCTargetAsmParser> TAP(
417       TheTarget->createMCAsmParser(*STI, *Parser, *MCII, Options));
418   if (!TAP)
419     Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
420 
421   if (!Failed) {
422     Parser->setTargetParser(*TAP.get());
423     Failed = Parser->Run(Opts.NoInitialTextSection);
424   }
425 
426   // Close Streamer first.
427   // It might have a reference to the output stream.
428   Str.reset();
429   // Close the output stream early.
430   BOS.reset();
431   FDOS.reset();
432 
433   // Delete output file if there were errors.
434   if (Failed && Opts.OutputPath != "-")
435     sys::fs::remove(Opts.OutputPath);
436 
437   return Failed;
438 }
439 
LLVMErrorHandler(void * UserData,const std::string & Message,bool GenCrashDiag)440 static void LLVMErrorHandler(void *UserData, const std::string &Message,
441                              bool GenCrashDiag) {
442   DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
443 
444   Diags.Report(diag::err_fe_error_backend) << Message;
445 
446   // We cannot recover from llvm errors.
447   exit(1);
448 }
449 
cc1as_main(ArrayRef<const char * > Argv,const char * Argv0,void * MainAddr)450 int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
451   // Initialize targets and assembly printers/parsers.
452   InitializeAllTargetInfos();
453   InitializeAllTargetMCs();
454   InitializeAllAsmParsers();
455 
456   // Construct our diagnostic client.
457   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
458   TextDiagnosticPrinter *DiagClient
459     = new TextDiagnosticPrinter(errs(), &*DiagOpts);
460   DiagClient->setPrefix("clang -cc1as");
461   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
462   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
463 
464   // Set an error handler, so that any LLVM backend diagnostics go through our
465   // error handler.
466   ScopedFatalErrorHandler FatalErrorHandler
467     (LLVMErrorHandler, static_cast<void*>(&Diags));
468 
469   // Parse the arguments.
470   AssemblerInvocation Asm;
471   if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
472     return 1;
473 
474   if (Asm.ShowHelp) {
475     std::unique_ptr<OptTable> Opts(driver::createDriverOptTable());
476     Opts->PrintHelp(llvm::outs(), "clang -cc1as", "Clang Integrated Assembler",
477                     /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0);
478     return 0;
479   }
480 
481   // Honor -version.
482   //
483   // FIXME: Use a better -version message?
484   if (Asm.ShowVersion) {
485     llvm::cl::PrintVersionMessage();
486     return 0;
487   }
488 
489   // Honor -mllvm.
490   //
491   // FIXME: Remove this, one day.
492   if (!Asm.LLVMArgs.empty()) {
493     unsigned NumArgs = Asm.LLVMArgs.size();
494     const char **Args = new const char*[NumArgs + 2];
495     Args[0] = "clang (LLVM option parsing)";
496     for (unsigned i = 0; i != NumArgs; ++i)
497       Args[i + 1] = Asm.LLVMArgs[i].c_str();
498     Args[NumArgs + 1] = nullptr;
499     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args);
500   }
501 
502   // Execute the invocation, unless there were parsing errors.
503   bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
504 
505   // If any timers were active but haven't been destroyed yet, print their
506   // results now.
507   TimerGroup::printAll(errs());
508 
509   return !!Failed;
510 }
511