1//===-- cc1as_main.cpp - Clang Assembler  ---------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is the entry point to the clang -cc1as functionality, which implements
11// the direct interface to the LLVM MC based assembler.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Basic/Diagnostic.h"
16#include "clang/Basic/DiagnosticOptions.h"
17#include "clang/Driver/DriverDiagnostic.h"
18#include "clang/Driver/Options.h"
19#include "clang/Frontend/FrontendDiagnostic.h"
20#include "clang/Frontend/TextDiagnosticPrinter.h"
21#include "clang/Frontend/Utils.h"
22#include "llvm/ADT/STLExtras.h"
23#include "llvm/ADT/StringSwitch.h"
24#include "llvm/ADT/Triple.h"
25#include "llvm/IR/DataLayout.h"
26#include "llvm/MC/MCAsmBackend.h"
27#include "llvm/MC/MCAsmInfo.h"
28#include "llvm/MC/MCCodeEmitter.h"
29#include "llvm/MC/MCContext.h"
30#include "llvm/MC/MCInstrInfo.h"
31#include "llvm/MC/MCObjectFileInfo.h"
32#include "llvm/MC/MCParser/MCAsmParser.h"
33#include "llvm/MC/MCRegisterInfo.h"
34#include "llvm/MC/MCStreamer.h"
35#include "llvm/MC/MCSubtargetInfo.h"
36#include "llvm/MC/MCTargetAsmParser.h"
37#include "llvm/MC/MCTargetOptions.h"
38#include "llvm/Option/Arg.h"
39#include "llvm/Option/ArgList.h"
40#include "llvm/Option/OptTable.h"
41#include "llvm/Support/CommandLine.h"
42#include "llvm/Support/ErrorHandling.h"
43#include "llvm/Support/FileSystem.h"
44#include "llvm/Support/FormattedStream.h"
45#include "llvm/Support/Host.h"
46#include "llvm/Support/ManagedStatic.h"
47#include "llvm/Support/MemoryBuffer.h"
48#include "llvm/Support/Path.h"
49#include "llvm/Support/PrettyStackTrace.h"
50#include "llvm/Support/Signals.h"
51#include "llvm/Support/SourceMgr.h"
52#include "llvm/Support/TargetRegistry.h"
53#include "llvm/Support/TargetSelect.h"
54#include "llvm/Support/Timer.h"
55#include "llvm/Support/raw_ostream.h"
56#include <memory>
57#include <system_error>
58using namespace clang;
59using namespace clang::driver;
60using namespace clang::driver::options;
61using namespace llvm;
62using namespace llvm::opt;
63
64namespace {
65
66/// \brief Helper class for representing a single invocation of the assembler.
67struct AssemblerInvocation {
68  /// @name Target Options
69  /// @{
70
71  /// The name of the target triple to assemble for.
72  std::string Triple;
73
74  /// If given, the name of the target CPU to determine which instructions
75  /// are legal.
76  std::string CPU;
77
78  /// The list of target specific features to enable or disable -- this should
79  /// be a list of strings starting with '+' or '-'.
80  std::vector<std::string> Features;
81
82  /// @}
83  /// @name Language Options
84  /// @{
85
86  std::vector<std::string> IncludePaths;
87  unsigned NoInitialTextSection : 1;
88  unsigned SaveTemporaryLabels : 1;
89  unsigned GenDwarfForAssembly : 1;
90  unsigned CompressDebugSections : 1;
91  unsigned DwarfVersion;
92  std::string DwarfDebugFlags;
93  std::string DwarfDebugProducer;
94  std::string DebugCompilationDir;
95  std::string MainFileName;
96
97  /// @}
98  /// @name Frontend Options
99  /// @{
100
101  std::string InputFile;
102  std::vector<std::string> LLVMArgs;
103  std::string OutputPath;
104  enum FileType {
105    FT_Asm,  ///< Assembly (.s) output, transliterate mode.
106    FT_Null, ///< No output, for timing purposes.
107    FT_Obj   ///< Object file output.
108  };
109  FileType OutputType;
110  unsigned ShowHelp : 1;
111  unsigned ShowVersion : 1;
112
113  /// @}
114  /// @name Transliterate Options
115  /// @{
116
117  unsigned OutputAsmVariant;
118  unsigned ShowEncoding : 1;
119  unsigned ShowInst : 1;
120
121  /// @}
122  /// @name Assembler Options
123  /// @{
124
125  unsigned RelaxAll : 1;
126  unsigned NoExecStack : 1;
127  unsigned FatalWarnings : 1;
128
129  /// @}
130
131public:
132  AssemblerInvocation() {
133    Triple = "";
134    NoInitialTextSection = 0;
135    InputFile = "-";
136    OutputPath = "-";
137    OutputType = FT_Asm;
138    OutputAsmVariant = 0;
139    ShowInst = 0;
140    ShowEncoding = 0;
141    RelaxAll = 0;
142    NoExecStack = 0;
143    FatalWarnings = 0;
144    DwarfVersion = 3;
145  }
146
147  static bool CreateFromArgs(AssemblerInvocation &Res,
148                             ArrayRef<const char *> Argv,
149                             DiagnosticsEngine &Diags);
150};
151
152}
153
154bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
155                                         ArrayRef<const char *> Argv,
156                                         DiagnosticsEngine &Diags) {
157  bool Success = true;
158
159  // Parse the arguments.
160  std::unique_ptr<OptTable> OptTbl(createDriverOptTable());
161
162  const unsigned IncludedFlagsBitmask = options::CC1AsOption;
163  unsigned MissingArgIndex, MissingArgCount;
164  std::unique_ptr<InputArgList> Args(
165      OptTbl->ParseArgs(Argv.begin(), Argv.end(), MissingArgIndex, MissingArgCount,
166                        IncludedFlagsBitmask));
167
168  // Check for missing argument error.
169  if (MissingArgCount) {
170    Diags.Report(diag::err_drv_missing_argument)
171        << Args->getArgString(MissingArgIndex) << MissingArgCount;
172    Success = false;
173  }
174
175  // Issue errors on unknown arguments.
176  for (arg_iterator it = Args->filtered_begin(OPT_UNKNOWN),
177                    ie = Args->filtered_end();
178       it != ie; ++it) {
179    Diags.Report(diag::err_drv_unknown_argument) << (*it)->getAsString(*Args);
180    Success = false;
181  }
182
183  // Construct the invocation.
184
185  // Target Options
186  Opts.Triple = llvm::Triple::normalize(Args->getLastArgValue(OPT_triple));
187  Opts.CPU = Args->getLastArgValue(OPT_target_cpu);
188  Opts.Features = Args->getAllArgValues(OPT_target_feature);
189
190  // Use the default target triple if unspecified.
191  if (Opts.Triple.empty())
192    Opts.Triple = llvm::sys::getDefaultTargetTriple();
193
194  // Language Options
195  Opts.IncludePaths = Args->getAllArgValues(OPT_I);
196  Opts.NoInitialTextSection = Args->hasArg(OPT_n);
197  Opts.SaveTemporaryLabels = Args->hasArg(OPT_msave_temp_labels);
198  Opts.GenDwarfForAssembly = Args->hasArg(OPT_g_Flag);
199  Opts.CompressDebugSections = Args->hasArg(OPT_compress_debug_sections);
200  if (Args->hasArg(OPT_gdwarf_2))
201    Opts.DwarfVersion = 2;
202  if (Args->hasArg(OPT_gdwarf_3))
203    Opts.DwarfVersion = 3;
204  if (Args->hasArg(OPT_gdwarf_4))
205    Opts.DwarfVersion = 4;
206  Opts.DwarfDebugFlags = Args->getLastArgValue(OPT_dwarf_debug_flags);
207  Opts.DwarfDebugProducer = Args->getLastArgValue(OPT_dwarf_debug_producer);
208  Opts.DebugCompilationDir = Args->getLastArgValue(OPT_fdebug_compilation_dir);
209  Opts.MainFileName = Args->getLastArgValue(OPT_main_file_name);
210
211  // Frontend Options
212  if (Args->hasArg(OPT_INPUT)) {
213    bool First = true;
214    for (arg_iterator it = Args->filtered_begin(OPT_INPUT),
215           ie = Args->filtered_end(); it != ie; ++it, First=false) {
216      const Arg *A = it;
217      if (First)
218        Opts.InputFile = A->getValue();
219      else {
220        Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(*Args);
221        Success = false;
222      }
223    }
224  }
225  Opts.LLVMArgs = Args->getAllArgValues(OPT_mllvm);
226  Opts.OutputPath = Args->getLastArgValue(OPT_o);
227  if (Arg *A = Args->getLastArg(OPT_filetype)) {
228    StringRef Name = A->getValue();
229    unsigned OutputType = StringSwitch<unsigned>(Name)
230      .Case("asm", FT_Asm)
231      .Case("null", FT_Null)
232      .Case("obj", FT_Obj)
233      .Default(~0U);
234    if (OutputType == ~0U) {
235      Diags.Report(diag::err_drv_invalid_value)
236        << A->getAsString(*Args) << Name;
237      Success = false;
238    } else
239      Opts.OutputType = FileType(OutputType);
240  }
241  Opts.ShowHelp = Args->hasArg(OPT_help);
242  Opts.ShowVersion = Args->hasArg(OPT_version);
243
244  // Transliterate Options
245  Opts.OutputAsmVariant =
246      getLastArgIntValue(*Args.get(), OPT_output_asm_variant, 0, Diags);
247  Opts.ShowEncoding = Args->hasArg(OPT_show_encoding);
248  Opts.ShowInst = Args->hasArg(OPT_show_inst);
249
250  // Assemble Options
251  Opts.RelaxAll = Args->hasArg(OPT_mrelax_all);
252  Opts.NoExecStack = Args->hasArg(OPT_mno_exec_stack);
253  Opts.FatalWarnings =  Args->hasArg(OPT_massembler_fatal_warnings);
254
255  return Success;
256}
257
258static std::unique_ptr<raw_fd_ostream>
259getOutputStream(AssemblerInvocation &Opts, DiagnosticsEngine &Diags,
260                bool Binary) {
261  if (Opts.OutputPath.empty())
262    Opts.OutputPath = "-";
263
264  // Make sure that the Out file gets unlinked from the disk if we get a
265  // SIGINT.
266  if (Opts.OutputPath != "-")
267    sys::RemoveFileOnSignal(Opts.OutputPath);
268
269  std::error_code EC;
270  auto Out = llvm::make_unique<raw_fd_ostream>(
271      Opts.OutputPath, EC, (Binary ? sys::fs::F_None : sys::fs::F_Text));
272  if (EC) {
273    Diags.Report(diag::err_fe_unable_to_open_output) << Opts.OutputPath
274                                                     << EC.message();
275    return nullptr;
276  }
277
278  return Out;
279}
280
281static bool ExecuteAssembler(AssemblerInvocation &Opts,
282                             DiagnosticsEngine &Diags) {
283  // Get the target specific parser.
284  std::string Error;
285  const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
286  if (!TheTarget)
287    return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
288
289  ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
290      MemoryBuffer::getFileOrSTDIN(Opts.InputFile);
291
292  if (std::error_code EC = Buffer.getError()) {
293    Error = EC.message();
294    return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
295  }
296
297  SourceMgr SrcMgr;
298
299  // Tell SrcMgr about this buffer, which is what the parser will pick up.
300  SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
301
302  // Record the location of the include directories so that the lexer can find
303  // it later.
304  SrcMgr.setIncludeDirs(Opts.IncludePaths);
305
306  std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
307  assert(MRI && "Unable to create target register info!");
308
309  std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, Opts.Triple));
310  assert(MAI && "Unable to create target asm info!");
311
312  // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
313  // may be created with a combination of default and explicit settings.
314  if (Opts.CompressDebugSections)
315    MAI->setCompressDebugSections(true);
316
317  bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
318  std::unique_ptr<raw_fd_ostream> FDOS = getOutputStream(Opts, Diags, IsBinary);
319  if (!FDOS)
320    return true;
321
322  // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
323  // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
324  std::unique_ptr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
325
326  MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &SrcMgr);
327  // FIXME: Assembler behavior can change with -static.
328  MOFI->InitMCObjectFileInfo(Opts.Triple,
329                             Reloc::Default, CodeModel::Default, Ctx);
330  if (Opts.SaveTemporaryLabels)
331    Ctx.setAllowTemporaryLabels(false);
332  if (Opts.GenDwarfForAssembly)
333    Ctx.setGenDwarfForAssembly(true);
334  if (!Opts.DwarfDebugFlags.empty())
335    Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
336  if (!Opts.DwarfDebugProducer.empty())
337    Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
338  if (!Opts.DebugCompilationDir.empty())
339    Ctx.setCompilationDir(Opts.DebugCompilationDir);
340  if (!Opts.MainFileName.empty())
341    Ctx.setMainFileName(StringRef(Opts.MainFileName));
342  Ctx.setDwarfVersion(Opts.DwarfVersion);
343
344  // Build up the feature string from the target feature list.
345  std::string FS;
346  if (!Opts.Features.empty()) {
347    FS = Opts.Features[0];
348    for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
349      FS += "," + Opts.Features[i];
350  }
351
352  std::unique_ptr<MCStreamer> Str;
353
354  std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
355  std::unique_ptr<MCSubtargetInfo> STI(
356      TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
357
358  raw_pwrite_stream *Out = FDOS.get();
359  std::unique_ptr<buffer_ostream> BOS;
360
361  // FIXME: There is a bit of code duplication with addPassesToEmitFile.
362  if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
363    MCInstPrinter *IP = TheTarget->createMCInstPrinter(
364        llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
365    MCCodeEmitter *CE = nullptr;
366    MCAsmBackend *MAB = nullptr;
367    if (Opts.ShowEncoding) {
368      CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
369      MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple, Opts.CPU);
370    }
371    auto FOut = llvm::make_unique<formatted_raw_ostream>(*Out);
372    Str.reset(TheTarget->createAsmStreamer(
373        Ctx, std::move(FOut), /*asmverbose*/ true,
374        /*useDwarfDirectory*/ true, IP, CE, MAB, Opts.ShowInst));
375  } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
376    Str.reset(createNullStreamer(Ctx));
377  } else {
378    assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
379           "Invalid file type!");
380    if (!FDOS->supportsSeeking()) {
381      BOS = make_unique<buffer_ostream>(*FDOS);
382      Out = BOS.get();
383    }
384
385    MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
386    MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, Opts.Triple,
387                                                      Opts.CPU);
388    Triple T(Opts.Triple);
389    Str.reset(TheTarget->createMCObjectStreamer(T, Ctx, *MAB, *Out, CE, *STI,
390                                                Opts.RelaxAll,
391                                                /*DWARFMustBeAtTheEnd*/ true));
392    Str.get()->InitSections(Opts.NoExecStack);
393  }
394
395  bool Failed = false;
396
397  std::unique_ptr<MCAsmParser> Parser(
398      createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
399
400  // FIXME: init MCTargetOptions from sanitizer flags here.
401  MCTargetOptions Options;
402  std::unique_ptr<MCTargetAsmParser> TAP(
403      TheTarget->createMCAsmParser(*STI, *Parser, *MCII, Options));
404  if (!TAP)
405    Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
406
407  if (!Failed) {
408    Parser->setTargetParser(*TAP.get());
409    Failed = Parser->Run(Opts.NoInitialTextSection);
410  }
411
412  // Close the output stream early.
413  BOS.reset();
414  FDOS.reset();
415
416  // Delete output file if there were errors.
417  if (Failed && Opts.OutputPath != "-")
418    sys::fs::remove(Opts.OutputPath);
419
420  return Failed;
421}
422
423static void LLVMErrorHandler(void *UserData, const std::string &Message,
424                             bool GenCrashDiag) {
425  DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
426
427  Diags.Report(diag::err_fe_error_backend) << Message;
428
429  // We cannot recover from llvm errors.
430  exit(1);
431}
432
433int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
434  // Print a stack trace if we signal out.
435  sys::PrintStackTraceOnErrorSignal();
436  PrettyStackTraceProgram X(Argv.size(), Argv.data());
437  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
438
439  // Initialize targets and assembly printers/parsers.
440  InitializeAllTargetInfos();
441  InitializeAllTargetMCs();
442  InitializeAllAsmParsers();
443
444  // Construct our diagnostic client.
445  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
446  TextDiagnosticPrinter *DiagClient
447    = new TextDiagnosticPrinter(errs(), &*DiagOpts);
448  DiagClient->setPrefix("clang -cc1as");
449  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
450  DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
451
452  // Set an error handler, so that any LLVM backend diagnostics go through our
453  // error handler.
454  ScopedFatalErrorHandler FatalErrorHandler
455    (LLVMErrorHandler, static_cast<void*>(&Diags));
456
457  // Parse the arguments.
458  AssemblerInvocation Asm;
459  if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
460    return 1;
461
462  if (Asm.ShowHelp) {
463    std::unique_ptr<OptTable> Opts(driver::createDriverOptTable());
464    Opts->PrintHelp(llvm::outs(), "clang -cc1as", "Clang Integrated Assembler",
465                    /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0);
466    return 0;
467  }
468
469  // Honor -version.
470  //
471  // FIXME: Use a better -version message?
472  if (Asm.ShowVersion) {
473    llvm::cl::PrintVersionMessage();
474    return 0;
475  }
476
477  // Honor -mllvm.
478  //
479  // FIXME: Remove this, one day.
480  if (!Asm.LLVMArgs.empty()) {
481    unsigned NumArgs = Asm.LLVMArgs.size();
482    const char **Args = new const char*[NumArgs + 2];
483    Args[0] = "clang (LLVM option parsing)";
484    for (unsigned i = 0; i != NumArgs; ++i)
485      Args[i + 1] = Asm.LLVMArgs[i].c_str();
486    Args[NumArgs + 1] = nullptr;
487    llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args);
488  }
489
490  // Execute the invocation, unless there were parsing errors.
491  bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
492
493  // If any timers were active but haven't been destroyed yet, print their
494  // results now.
495  TimerGroup::printAll(errs());
496
497  return !!Failed;
498}
499
500