1//===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
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 llc code generator driver. It provides a convenient
10// command-line interface for generating native assembly-language code
11// or C code, given LLVM bitcode.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/ADT/Triple.h"
17#include "llvm/Analysis/TargetLibraryInfo.h"
18#include "llvm/CodeGen/CommandFlags.inc"
19#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
20#include "llvm/CodeGen/LinkAllCodegenComponents.h"
21#include "llvm/CodeGen/MIRParser/MIRParser.h"
22#include "llvm/CodeGen/MachineFunctionPass.h"
23#include "llvm/CodeGen/MachineModuleInfo.h"
24#include "llvm/CodeGen/TargetPassConfig.h"
25#include "llvm/CodeGen/TargetSubtargetInfo.h"
26#include "llvm/IR/AutoUpgrade.h"
27#include "llvm/IR/DataLayout.h"
28#include "llvm/IR/DiagnosticInfo.h"
29#include "llvm/IR/DiagnosticPrinter.h"
30#include "llvm/IR/IRPrintingPasses.h"
31#include "llvm/IR/LLVMContext.h"
32#include "llvm/IR/LegacyPassManager.h"
33#include "llvm/IR/Module.h"
34#include "llvm/IR/RemarkStreamer.h"
35#include "llvm/IR/Verifier.h"
36#include "llvm/IRReader/IRReader.h"
37#include "llvm/InitializePasses.h"
38#include "llvm/MC/SubtargetFeature.h"
39#include "llvm/Pass.h"
40#include "llvm/Support/CommandLine.h"
41#include "llvm/Support/Debug.h"
42#include "llvm/Support/FileSystem.h"
43#include "llvm/Support/FormattedStream.h"
44#include "llvm/Support/Host.h"
45#include "llvm/Support/InitLLVM.h"
46#include "llvm/Support/ManagedStatic.h"
47#include "llvm/Support/PluginLoader.h"
48#include "llvm/Support/SourceMgr.h"
49#include "llvm/Support/TargetRegistry.h"
50#include "llvm/Support/TargetSelect.h"
51#include "llvm/Support/ToolOutputFile.h"
52#include "llvm/Support/WithColor.h"
53#include "llvm/Target/TargetMachine.h"
54#include "llvm/Transforms/Utils/Cloning.h"
55#include <memory>
56using namespace llvm;
57
58// General options for llc.  Other pass-specific options are specified
59// within the corresponding llc passes, and target-specific options
60// and back-end code generation options are specified with the target machine.
61//
62static cl::opt<std::string>
63InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
64
65static cl::opt<std::string>
66InputLanguage("x", cl::desc("Input language ('ir' or 'mir')"));
67
68static cl::opt<std::string>
69OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
70
71static cl::opt<std::string>
72    SplitDwarfOutputFile("split-dwarf-output",
73                         cl::desc(".dwo output filename"),
74                         cl::value_desc("filename"));
75
76static cl::opt<unsigned>
77TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
78                 cl::value_desc("N"),
79                 cl::desc("Repeat compilation N times for timing"));
80
81static cl::opt<bool>
82NoIntegratedAssembler("no-integrated-as", cl::Hidden,
83                      cl::desc("Disable integrated assembler"));
84
85static cl::opt<bool>
86    PreserveComments("preserve-as-comments", cl::Hidden,
87                     cl::desc("Preserve Comments in outputted assembly"),
88                     cl::init(true));
89
90// Determine optimization level.
91static cl::opt<char>
92OptLevel("O",
93         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
94                  "(default = '-O2')"),
95         cl::Prefix,
96         cl::ZeroOrMore,
97         cl::init(' '));
98
99static cl::opt<std::string>
100TargetTriple("mtriple", cl::desc("Override target triple for module"));
101
102static cl::opt<std::string> SplitDwarfFile(
103    "split-dwarf-file",
104    cl::desc(
105        "Specify the name of the .dwo file to encode in the DWARF output"));
106
107static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
108                              cl::desc("Do not verify input module"));
109
110static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
111                                             cl::desc("Disable simplify-libcalls"));
112
113static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
114                                    cl::desc("Show encoding in .s output"));
115
116static cl::opt<bool> EnableDwarfDirectory(
117    "enable-dwarf-directory", cl::Hidden,
118    cl::desc("Use .file directives with an explicit directory."));
119
120static cl::opt<bool> AsmVerbose("asm-verbose",
121                                cl::desc("Add comments to directives."),
122                                cl::init(true));
123
124static cl::opt<bool>
125    CompileTwice("compile-twice", cl::Hidden,
126                 cl::desc("Run everything twice, re-using the same pass "
127                          "manager and verify the result is the same."),
128                 cl::init(false));
129
130static cl::opt<bool> DiscardValueNames(
131    "discard-value-names",
132    cl::desc("Discard names from Value (other than GlobalValue)."),
133    cl::init(false), cl::Hidden);
134
135static cl::list<std::string> IncludeDirs("I", cl::desc("include search path"));
136
137static cl::opt<bool> RemarksWithHotness(
138    "pass-remarks-with-hotness",
139    cl::desc("With PGO, include profile count in optimization remarks"),
140    cl::Hidden);
141
142static cl::opt<unsigned>
143    RemarksHotnessThreshold("pass-remarks-hotness-threshold",
144                            cl::desc("Minimum profile count required for "
145                                     "an optimization remark to be output"),
146                            cl::Hidden);
147
148static cl::opt<std::string>
149    RemarksFilename("pass-remarks-output",
150                    cl::desc("Output filename for pass remarks"),
151                    cl::value_desc("filename"));
152
153static cl::opt<std::string>
154    RemarksPasses("pass-remarks-filter",
155                  cl::desc("Only record optimization remarks from passes whose "
156                           "names match the given regular expression"),
157                  cl::value_desc("regex"));
158
159static cl::opt<std::string> RemarksFormat(
160    "pass-remarks-format",
161    cl::desc("The format used for serializing remarks (default: YAML)"),
162    cl::value_desc("format"), cl::init("yaml"));
163
164namespace {
165static ManagedStatic<std::vector<std::string>> RunPassNames;
166
167struct RunPassOption {
168  void operator=(const std::string &Val) const {
169    if (Val.empty())
170      return;
171    SmallVector<StringRef, 8> PassNames;
172    StringRef(Val).split(PassNames, ',', -1, false);
173    for (auto PassName : PassNames)
174      RunPassNames->push_back(PassName);
175  }
176};
177}
178
179static RunPassOption RunPassOpt;
180
181static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass(
182    "run-pass",
183    cl::desc("Run compiler only for specified passes (comma separated list)"),
184    cl::value_desc("pass-name"), cl::ZeroOrMore, cl::location(RunPassOpt));
185
186static int compileModule(char **, LLVMContext &);
187
188static std::unique_ptr<ToolOutputFile> GetOutputStream(const char *TargetName,
189                                                       Triple::OSType OS,
190                                                       const char *ProgName) {
191  // If we don't yet have an output filename, make one.
192  if (OutputFilename.empty()) {
193    if (InputFilename == "-")
194      OutputFilename = "-";
195    else {
196      // If InputFilename ends in .bc or .ll, remove it.
197      StringRef IFN = InputFilename;
198      if (IFN.endswith(".bc") || IFN.endswith(".ll"))
199        OutputFilename = IFN.drop_back(3);
200      else if (IFN.endswith(".mir"))
201        OutputFilename = IFN.drop_back(4);
202      else
203        OutputFilename = IFN;
204
205      switch (FileType) {
206      case CGFT_AssemblyFile:
207        if (TargetName[0] == 'c') {
208          if (TargetName[1] == 0)
209            OutputFilename += ".cbe.c";
210          else if (TargetName[1] == 'p' && TargetName[2] == 'p')
211            OutputFilename += ".cpp";
212          else
213            OutputFilename += ".s";
214        } else
215          OutputFilename += ".s";
216        break;
217      case CGFT_ObjectFile:
218        if (OS == Triple::Win32)
219          OutputFilename += ".obj";
220        else
221          OutputFilename += ".o";
222        break;
223      case CGFT_Null:
224        OutputFilename += ".null";
225        break;
226      }
227    }
228  }
229
230  // Decide if we need "binary" output.
231  bool Binary = false;
232  switch (FileType) {
233  case CGFT_AssemblyFile:
234    break;
235  case CGFT_ObjectFile:
236  case CGFT_Null:
237    Binary = true;
238    break;
239  }
240
241  // Open the file.
242  std::error_code EC;
243  sys::fs::OpenFlags OpenFlags = sys::fs::OF_None;
244  if (!Binary)
245    OpenFlags |= sys::fs::OF_Text;
246  auto FDOut = std::make_unique<ToolOutputFile>(OutputFilename, EC, OpenFlags);
247  if (EC) {
248    WithColor::error() << EC.message() << '\n';
249    return nullptr;
250  }
251
252  return FDOut;
253}
254
255struct LLCDiagnosticHandler : public DiagnosticHandler {
256  bool *HasError;
257  LLCDiagnosticHandler(bool *HasErrorPtr) : HasError(HasErrorPtr) {}
258  bool handleDiagnostics(const DiagnosticInfo &DI) override {
259    if (DI.getSeverity() == DS_Error)
260      *HasError = true;
261
262    if (auto *Remark = dyn_cast<DiagnosticInfoOptimizationBase>(&DI))
263      if (!Remark->isEnabled())
264        return true;
265
266    DiagnosticPrinterRawOStream DP(errs());
267    errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
268    DI.print(DP);
269    errs() << "\n";
270    return true;
271  }
272};
273
274static void InlineAsmDiagHandler(const SMDiagnostic &SMD, void *Context,
275                                 unsigned LocCookie) {
276  bool *HasError = static_cast<bool *>(Context);
277  if (SMD.getKind() == SourceMgr::DK_Error)
278    *HasError = true;
279
280  SMD.print(nullptr, errs());
281
282  // For testing purposes, we print the LocCookie here.
283  if (LocCookie)
284    WithColor::note() << "!srcloc = " << LocCookie << "\n";
285}
286
287// main - Entry point for the llc compiler.
288//
289int main(int argc, char **argv) {
290  InitLLVM X(argc, argv);
291
292  // Enable debug stream buffering.
293  EnableDebugBuffering = true;
294
295  LLVMContext Context;
296
297  // Initialize targets first, so that --version shows registered targets.
298  InitializeAllTargets();
299  InitializeAllTargetMCs();
300  InitializeAllAsmPrinters();
301  InitializeAllAsmParsers();
302
303  // Initialize codegen and IR passes used by llc so that the -print-after,
304  // -print-before, and -stop-after options work.
305  PassRegistry *Registry = PassRegistry::getPassRegistry();
306  initializeCore(*Registry);
307  initializeCodeGen(*Registry);
308  initializeLoopStrengthReducePass(*Registry);
309  initializeLowerIntrinsicsPass(*Registry);
310  initializeEntryExitInstrumenterPass(*Registry);
311  initializePostInlineEntryExitInstrumenterPass(*Registry);
312  initializeUnreachableBlockElimLegacyPassPass(*Registry);
313  initializeConstantHoistingLegacyPassPass(*Registry);
314  initializeScalarOpts(*Registry);
315  initializeVectorization(*Registry);
316  initializeScalarizeMaskedMemIntrinPass(*Registry);
317  initializeExpandReductionsPass(*Registry);
318  initializeHardwareLoopsPass(*Registry);
319
320  // Initialize debugging passes.
321  initializeScavengerTestPass(*Registry);
322
323  // Register the target printer for --version.
324  cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
325
326  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
327
328  Context.setDiscardValueNames(DiscardValueNames);
329
330  // Set a diagnostic handler that doesn't exit on the first error
331  bool HasError = false;
332  Context.setDiagnosticHandler(
333      std::make_unique<LLCDiagnosticHandler>(&HasError));
334  Context.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, &HasError);
335
336  Expected<std::unique_ptr<ToolOutputFile>> RemarksFileOrErr =
337      setupOptimizationRemarks(Context, RemarksFilename, RemarksPasses,
338                               RemarksFormat, RemarksWithHotness,
339                               RemarksHotnessThreshold);
340  if (Error E = RemarksFileOrErr.takeError()) {
341    WithColor::error(errs(), argv[0]) << toString(std::move(E)) << '\n';
342    return 1;
343  }
344  std::unique_ptr<ToolOutputFile> RemarksFile = std::move(*RemarksFileOrErr);
345
346  if (InputLanguage != "" && InputLanguage != "ir" &&
347      InputLanguage != "mir") {
348    WithColor::error(errs(), argv[0])
349        << "input language must be '', 'IR' or 'MIR'\n";
350    return 1;
351  }
352
353  // Compile the module TimeCompilations times to give better compile time
354  // metrics.
355  for (unsigned I = TimeCompilations; I; --I)
356    if (int RetVal = compileModule(argv, Context))
357      return RetVal;
358
359  if (RemarksFile)
360    RemarksFile->keep();
361  return 0;
362}
363
364static bool addPass(PassManagerBase &PM, const char *argv0,
365                    StringRef PassName, TargetPassConfig &TPC) {
366  if (PassName == "none")
367    return false;
368
369  const PassRegistry *PR = PassRegistry::getPassRegistry();
370  const PassInfo *PI = PR->getPassInfo(PassName);
371  if (!PI) {
372    WithColor::error(errs(), argv0)
373        << "run-pass " << PassName << " is not registered.\n";
374    return true;
375  }
376
377  Pass *P;
378  if (PI->getNormalCtor())
379    P = PI->getNormalCtor()();
380  else {
381    WithColor::error(errs(), argv0)
382        << "cannot create pass: " << PI->getPassName() << "\n";
383    return true;
384  }
385  std::string Banner = std::string("After ") + std::string(P->getPassName());
386  PM.add(P);
387  TPC.printAndVerify(Banner);
388
389  return false;
390}
391
392static int compileModule(char **argv, LLVMContext &Context) {
393  // Load the module to be compiled...
394  SMDiagnostic Err;
395  std::unique_ptr<Module> M;
396  std::unique_ptr<MIRParser> MIR;
397  Triple TheTriple;
398  std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr();
399
400  // Set attributes on functions as loaded from MIR from command line arguments.
401  auto setMIRFunctionAttributes = [&CPUStr, &FeaturesStr](Function &F) {
402    setFunctionAttributes(CPUStr, FeaturesStr, F);
403  };
404
405  bool SkipModule = MCPU == "help" ||
406                    (!MAttrs.empty() && MAttrs.front() == "help");
407
408  // If user just wants to list available options, skip module loading
409  if (!SkipModule) {
410    if (InputLanguage == "mir" ||
411        (InputLanguage == "" && StringRef(InputFilename).endswith(".mir"))) {
412      MIR = createMIRParserFromFile(InputFilename, Err, Context,
413                                    setMIRFunctionAttributes);
414      if (MIR)
415        M = MIR->parseIRModule();
416    } else
417      M = parseIRFile(InputFilename, Err, Context, false);
418    if (!M) {
419      Err.print(argv[0], WithColor::error(errs(), argv[0]));
420      return 1;
421    }
422
423    // If we are supposed to override the target triple, do so now.
424    if (!TargetTriple.empty())
425      M->setTargetTriple(Triple::normalize(TargetTriple));
426    TheTriple = Triple(M->getTargetTriple());
427  } else {
428    TheTriple = Triple(Triple::normalize(TargetTriple));
429  }
430
431  if (TheTriple.getTriple().empty())
432    TheTriple.setTriple(sys::getDefaultTargetTriple());
433
434  // Get the target specific parser.
435  std::string Error;
436  const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
437                                                         Error);
438  if (!TheTarget) {
439    WithColor::error(errs(), argv[0]) << Error;
440    return 1;
441  }
442
443  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
444  switch (OptLevel) {
445  default:
446    WithColor::error(errs(), argv[0]) << "invalid optimization level.\n";
447    return 1;
448  case ' ': break;
449  case '0': OLvl = CodeGenOpt::None; break;
450  case '1': OLvl = CodeGenOpt::Less; break;
451  case '2': OLvl = CodeGenOpt::Default; break;
452  case '3': OLvl = CodeGenOpt::Aggressive; break;
453  }
454
455  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
456  Options.DisableIntegratedAS = NoIntegratedAssembler;
457  Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
458  Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory;
459  Options.MCOptions.AsmVerbose = AsmVerbose;
460  Options.MCOptions.PreserveAsmComments = PreserveComments;
461  Options.MCOptions.IASSearchPaths = IncludeDirs;
462  Options.MCOptions.SplitDwarfFile = SplitDwarfFile;
463
464  std::unique_ptr<TargetMachine> Target(TheTarget->createTargetMachine(
465      TheTriple.getTriple(), CPUStr, FeaturesStr, Options, getRelocModel(),
466      getCodeModel(), OLvl));
467
468  assert(Target && "Could not allocate target machine!");
469
470  // If we don't have a module then just exit now. We do this down
471  // here since the CPU/Feature help is underneath the target machine
472  // creation.
473  if (SkipModule)
474    return 0;
475
476  assert(M && "Should have exited if we didn't have a module!");
477  if (FloatABIForCalls != FloatABI::Default)
478    Options.FloatABIType = FloatABIForCalls;
479
480  // Figure out where we are going to send the output.
481  std::unique_ptr<ToolOutputFile> Out =
482      GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
483  if (!Out) return 1;
484
485  std::unique_ptr<ToolOutputFile> DwoOut;
486  if (!SplitDwarfOutputFile.empty()) {
487    std::error_code EC;
488    DwoOut = std::make_unique<ToolOutputFile>(SplitDwarfOutputFile, EC,
489                                               sys::fs::OF_None);
490    if (EC) {
491      WithColor::error(errs(), argv[0]) << EC.message() << '\n';
492      return 1;
493    }
494  }
495
496  // Build up all of the passes that we want to do to the module.
497  legacy::PassManager PM;
498
499  // Add an appropriate TargetLibraryInfo pass for the module's triple.
500  TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
501
502  // The -disable-simplify-libcalls flag actually disables all builtin optzns.
503  if (DisableSimplifyLibCalls)
504    TLII.disableAllFunctions();
505  PM.add(new TargetLibraryInfoWrapperPass(TLII));
506
507  // Add the target data from the target machine, if it exists, or the module.
508  M->setDataLayout(Target->createDataLayout());
509
510  // This needs to be done after setting datalayout since it calls verifier
511  // to check debug info whereas verifier relies on correct datalayout.
512  UpgradeDebugInfo(*M);
513
514  // Verify module immediately to catch problems before doInitialization() is
515  // called on any passes.
516  if (!NoVerify && verifyModule(*M, &errs())) {
517    std::string Prefix =
518        (Twine(argv[0]) + Twine(": ") + Twine(InputFilename)).str();
519    WithColor::error(errs(), Prefix) << "input module is broken!\n";
520    return 1;
521  }
522
523  // Override function attributes based on CPUStr, FeaturesStr, and command line
524  // flags.
525  setFunctionAttributes(CPUStr, FeaturesStr, *M);
526
527  if (RelaxAll.getNumOccurrences() > 0 &&
528      FileType != CGFT_ObjectFile)
529    WithColor::warning(errs(), argv[0])
530        << ": warning: ignoring -mc-relax-all because filetype != obj";
531
532  {
533    raw_pwrite_stream *OS = &Out->os();
534
535    // Manually do the buffering rather than using buffer_ostream,
536    // so we can memcmp the contents in CompileTwice mode
537    SmallVector<char, 0> Buffer;
538    std::unique_ptr<raw_svector_ostream> BOS;
539    if ((FileType != CGFT_AssemblyFile &&
540         !Out->os().supportsSeeking()) ||
541        CompileTwice) {
542      BOS = std::make_unique<raw_svector_ostream>(Buffer);
543      OS = BOS.get();
544    }
545
546    const char *argv0 = argv[0];
547    LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine &>(*Target);
548    MachineModuleInfoWrapperPass *MMIWP =
549        new MachineModuleInfoWrapperPass(&LLVMTM);
550
551    // Construct a custom pass pipeline that starts after instruction
552    // selection.
553    if (!RunPassNames->empty()) {
554      if (!MIR) {
555        WithColor::warning(errs(), argv[0])
556            << "run-pass is for .mir file only.\n";
557        return 1;
558      }
559      TargetPassConfig &TPC = *LLVMTM.createPassConfig(PM);
560      if (TPC.hasLimitedCodeGenPipeline()) {
561        WithColor::warning(errs(), argv[0])
562            << "run-pass cannot be used with "
563            << TPC.getLimitedCodeGenPipelineReason(" and ") << ".\n";
564        return 1;
565      }
566
567      TPC.setDisableVerify(NoVerify);
568      PM.add(&TPC);
569      PM.add(MMIWP);
570      TPC.printAndVerify("");
571      for (const std::string &RunPassName : *RunPassNames) {
572        if (addPass(PM, argv0, RunPassName, TPC))
573          return 1;
574      }
575      TPC.setInitialized();
576      PM.add(createPrintMIRPass(*OS));
577      PM.add(createFreeMachineFunctionPass());
578    } else if (Target->addPassesToEmitFile(PM, *OS,
579                                           DwoOut ? &DwoOut->os() : nullptr,
580                                           FileType, NoVerify, MMIWP)) {
581      WithColor::warning(errs(), argv[0])
582          << "target does not support generation of this"
583          << " file type!\n";
584      return 1;
585    }
586
587    if (MIR) {
588      assert(MMIWP && "Forgot to create MMIWP?");
589      if (MIR->parseMachineFunctions(*M, MMIWP->getMMI()))
590        return 1;
591    }
592
593    // Before executing passes, print the final values of the LLVM options.
594    cl::PrintOptionValues();
595
596    // If requested, run the pass manager over the same module again,
597    // to catch any bugs due to persistent state in the passes. Note that
598    // opt has the same functionality, so it may be worth abstracting this out
599    // in the future.
600    SmallVector<char, 0> CompileTwiceBuffer;
601    if (CompileTwice) {
602      std::unique_ptr<Module> M2(llvm::CloneModule(*M));
603      PM.run(*M2);
604      CompileTwiceBuffer = Buffer;
605      Buffer.clear();
606    }
607
608    PM.run(*M);
609
610    auto HasError =
611        ((const LLCDiagnosticHandler *)(Context.getDiagHandlerPtr()))->HasError;
612    if (*HasError)
613      return 1;
614
615    // Compare the two outputs and make sure they're the same
616    if (CompileTwice) {
617      if (Buffer.size() != CompileTwiceBuffer.size() ||
618          (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
619           0)) {
620        errs()
621            << "Running the pass manager twice changed the output.\n"
622               "Writing the result of the second run to the specified output\n"
623               "To generate the one-run comparison binary, just run without\n"
624               "the compile-twice option\n";
625        Out->os() << Buffer;
626        Out->keep();
627        return 1;
628      }
629    }
630
631    if (BOS) {
632      Out->os() << Buffer;
633    }
634  }
635
636  // Declare success.
637  Out->keep();
638  if (DwoOut)
639    DwoOut->keep();
640
641  return 0;
642}
643