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>
56using namespace clang;
57using namespace clang::driver;
58using namespace clang::driver::options;
59using namespace llvm;
60using namespace llvm::opt;
61
62namespace {
63
64/// \brief Helper class for representing a single invocation of the assembler.
65struct 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
134public:
135  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
158bool 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
259static std::unique_ptr<raw_fd_ostream>
260getOutputStream(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
282static 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
440static 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
450int 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