1//===- opt.cpp - The LLVM Modular Optimizer -------------------------------===//
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// Optimizations may be specified an arbitrary number of times on the command
11// line, They are run in the order specified.
12//
13//===----------------------------------------------------------------------===//
14
15#include "BreakpointPrinter.h"
16#include "NewPMDriver.h"
17#include "PassPrinters.h"
18#include "llvm/ADT/Triple.h"
19#include "llvm/Analysis/CallGraph.h"
20#include "llvm/Analysis/CallGraphSCCPass.h"
21#include "llvm/Analysis/LoopPass.h"
22#include "llvm/Analysis/RegionPass.h"
23#include "llvm/Analysis/TargetLibraryInfo.h"
24#include "llvm/Analysis/TargetTransformInfo.h"
25#include "llvm/Bitcode/BitcodeWriterPass.h"
26#include "llvm/CodeGen/CommandFlags.h"
27#include "llvm/IR/DataLayout.h"
28#include "llvm/IR/DebugInfo.h"
29#include "llvm/IR/IRPrintingPasses.h"
30#include "llvm/IR/LLVMContext.h"
31#include "llvm/IR/LegacyPassManager.h"
32#include "llvm/IR/LegacyPassNameParser.h"
33#include "llvm/IR/Module.h"
34#include "llvm/IR/Verifier.h"
35#include "llvm/IRReader/IRReader.h"
36#include "llvm/InitializePasses.h"
37#include "llvm/LinkAllIR.h"
38#include "llvm/LinkAllPasses.h"
39#include "llvm/MC/SubtargetFeature.h"
40#include "llvm/Support/Debug.h"
41#include "llvm/Support/FileSystem.h"
42#include "llvm/Support/Host.h"
43#include "llvm/Support/ManagedStatic.h"
44#include "llvm/Support/PluginLoader.h"
45#include "llvm/Support/PrettyStackTrace.h"
46#include "llvm/Support/Signals.h"
47#include "llvm/Support/SourceMgr.h"
48#include "llvm/Support/SystemUtils.h"
49#include "llvm/Support/TargetRegistry.h"
50#include "llvm/Support/TargetSelect.h"
51#include "llvm/Support/ToolOutputFile.h"
52#include "llvm/Target/TargetMachine.h"
53#include "llvm/Transforms/IPO/PassManagerBuilder.h"
54#include "llvm/Transforms/Utils/Cloning.h"
55#include <algorithm>
56#include <memory>
57using namespace llvm;
58using namespace opt_tool;
59
60// The OptimizationList is automatically populated with registered Passes by the
61// PassNameParser.
62//
63static cl::list<const PassInfo*, bool, PassNameParser>
64PassList(cl::desc("Optimizations available:"));
65
66// This flag specifies a textual description of the optimization pass pipeline
67// to run over the module. This flag switches opt to use the new pass manager
68// infrastructure, completely disabling all of the flags specific to the old
69// pass management.
70static cl::opt<std::string> PassPipeline(
71    "passes",
72    cl::desc("A textual description of the pass pipeline for optimizing"),
73    cl::Hidden);
74
75// Other command line options...
76//
77static cl::opt<std::string>
78InputFilename(cl::Positional, cl::desc("<input bitcode file>"),
79    cl::init("-"), cl::value_desc("filename"));
80
81static cl::opt<std::string>
82OutputFilename("o", cl::desc("Override output filename"),
83               cl::value_desc("filename"));
84
85static cl::opt<bool>
86Force("f", cl::desc("Enable binary output on terminals"));
87
88static cl::opt<bool>
89PrintEachXForm("p", cl::desc("Print module after each transformation"));
90
91static cl::opt<bool>
92NoOutput("disable-output",
93         cl::desc("Do not write result bitcode file"), cl::Hidden);
94
95static cl::opt<bool>
96OutputAssembly("S", cl::desc("Write output as LLVM assembly"));
97
98static cl::opt<bool>
99NoVerify("disable-verify", cl::desc("Do not verify result module"), cl::Hidden);
100
101static cl::opt<bool>
102VerifyEach("verify-each", cl::desc("Verify after each transform"));
103
104static cl::opt<bool>
105StripDebug("strip-debug",
106           cl::desc("Strip debugger symbol info from translation unit"));
107
108static cl::opt<bool>
109DisableInline("disable-inlining", cl::desc("Do not run the inliner pass"));
110
111static cl::opt<bool>
112DisableOptimizations("disable-opt",
113                     cl::desc("Do not run any optimization passes"));
114
115static cl::opt<bool>
116StandardLinkOpts("std-link-opts",
117                 cl::desc("Include the standard link time optimizations"));
118
119static cl::opt<bool>
120OptLevelO1("O1",
121           cl::desc("Optimization level 1. Similar to clang -O1"));
122
123static cl::opt<bool>
124OptLevelO2("O2",
125           cl::desc("Optimization level 2. Similar to clang -O2"));
126
127static cl::opt<bool>
128OptLevelOs("Os",
129           cl::desc("Like -O2 with extra optimizations for size. Similar to clang -Os"));
130
131static cl::opt<bool>
132OptLevelOz("Oz",
133           cl::desc("Like -Os but reduces code size further. Similar to clang -Oz"));
134
135static cl::opt<bool>
136OptLevelO3("O3",
137           cl::desc("Optimization level 3. Similar to clang -O3"));
138
139static cl::opt<std::string>
140TargetTriple("mtriple", cl::desc("Override target triple for module"));
141
142static cl::opt<bool>
143UnitAtATime("funit-at-a-time",
144            cl::desc("Enable IPO. This corresponds to gcc's -funit-at-a-time"),
145            cl::init(true));
146
147static cl::opt<bool>
148DisableLoopUnrolling("disable-loop-unrolling",
149                     cl::desc("Disable loop unrolling in all relevant passes"),
150                     cl::init(false));
151static cl::opt<bool>
152DisableLoopVectorization("disable-loop-vectorization",
153                     cl::desc("Disable the loop vectorization pass"),
154                     cl::init(false));
155
156static cl::opt<bool>
157DisableSLPVectorization("disable-slp-vectorization",
158                        cl::desc("Disable the slp vectorization pass"),
159                        cl::init(false));
160
161
162static cl::opt<bool>
163DisableSimplifyLibCalls("disable-simplify-libcalls",
164                        cl::desc("Disable simplify-libcalls"));
165
166static cl::opt<bool>
167Quiet("q", cl::desc("Obsolete option"), cl::Hidden);
168
169static cl::alias
170QuietA("quiet", cl::desc("Alias for -q"), cl::aliasopt(Quiet));
171
172static cl::opt<bool>
173AnalyzeOnly("analyze", cl::desc("Only perform analysis, no optimization"));
174
175static cl::opt<bool>
176PrintBreakpoints("print-breakpoints-for-testing",
177                 cl::desc("Print select breakpoints location for testing"));
178
179static cl::opt<std::string>
180DefaultDataLayout("default-data-layout",
181          cl::desc("data layout string to use if not specified by module"),
182          cl::value_desc("layout-string"), cl::init(""));
183
184static cl::opt<bool> PreserveBitcodeUseListOrder(
185    "preserve-bc-uselistorder",
186    cl::desc("Preserve use-list order when writing LLVM bitcode."),
187    cl::init(true), cl::Hidden);
188
189static cl::opt<bool> PreserveAssemblyUseListOrder(
190    "preserve-ll-uselistorder",
191    cl::desc("Preserve use-list order when writing LLVM assembly."),
192    cl::init(false), cl::Hidden);
193
194static cl::opt<bool>
195    RunTwice("run-twice",
196             cl::desc("Run all passes twice, re-using the same pass manager."),
197             cl::init(false), cl::Hidden);
198
199static inline void addPass(legacy::PassManagerBase &PM, Pass *P) {
200  // Add the pass to the pass manager...
201  PM.add(P);
202
203  // If we are verifying all of the intermediate steps, add the verifier...
204  if (VerifyEach)
205    PM.add(createVerifierPass());
206}
207
208/// This routine adds optimization passes based on selected optimization level,
209/// OptLevel.
210///
211/// OptLevel - Optimization Level
212static void AddOptimizationPasses(legacy::PassManagerBase &MPM,
213                                  legacy::FunctionPassManager &FPM,
214                                  unsigned OptLevel, unsigned SizeLevel) {
215  FPM.add(createVerifierPass()); // Verify that input is correct
216
217  PassManagerBuilder Builder;
218  Builder.OptLevel = OptLevel;
219  Builder.SizeLevel = SizeLevel;
220
221  if (DisableInline) {
222    // No inlining pass
223  } else if (OptLevel > 1) {
224    Builder.Inliner = createFunctionInliningPass(OptLevel, SizeLevel);
225  } else {
226    Builder.Inliner = createAlwaysInlinerPass();
227  }
228  Builder.DisableUnitAtATime = !UnitAtATime;
229  Builder.DisableUnrollLoops = (DisableLoopUnrolling.getNumOccurrences() > 0) ?
230                               DisableLoopUnrolling : OptLevel == 0;
231
232  // This is final, unless there is a #pragma vectorize enable
233  if (DisableLoopVectorization)
234    Builder.LoopVectorize = false;
235  // If option wasn't forced via cmd line (-vectorize-loops, -loop-vectorize)
236  else if (!Builder.LoopVectorize)
237    Builder.LoopVectorize = OptLevel > 1 && SizeLevel < 2;
238
239  // When #pragma vectorize is on for SLP, do the same as above
240  Builder.SLPVectorize =
241      DisableSLPVectorization ? false : OptLevel > 1 && SizeLevel < 2;
242
243  Builder.populateFunctionPassManager(FPM);
244  Builder.populateModulePassManager(MPM);
245}
246
247static void AddStandardLinkPasses(legacy::PassManagerBase &PM) {
248  PassManagerBuilder Builder;
249  Builder.VerifyInput = true;
250  if (DisableOptimizations)
251    Builder.OptLevel = 0;
252
253  if (!DisableInline)
254    Builder.Inliner = createFunctionInliningPass();
255  Builder.populateLTOPassManager(PM);
256}
257
258//===----------------------------------------------------------------------===//
259// CodeGen-related helper functions.
260//
261
262static CodeGenOpt::Level GetCodeGenOptLevel() {
263  if (OptLevelO1)
264    return CodeGenOpt::Less;
265  if (OptLevelO2)
266    return CodeGenOpt::Default;
267  if (OptLevelO3)
268    return CodeGenOpt::Aggressive;
269  return CodeGenOpt::None;
270}
271
272// Returns the TargetMachine instance or zero if no triple is provided.
273static TargetMachine* GetTargetMachine(Triple TheTriple, StringRef CPUStr,
274                                       StringRef FeaturesStr,
275                                       const TargetOptions &Options) {
276  std::string Error;
277  const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
278                                                         Error);
279  // Some modules don't specify a triple, and this is okay.
280  if (!TheTarget) {
281    return nullptr;
282  }
283
284  return TheTarget->createTargetMachine(TheTriple.getTriple(),
285                                        CPUStr, FeaturesStr, Options,
286                                        RelocModel, CMModel,
287                                        GetCodeGenOptLevel());
288}
289
290#ifdef LINK_POLLY_INTO_TOOLS
291namespace polly {
292void initializePollyPasses(llvm::PassRegistry &Registry);
293}
294#endif
295
296//===----------------------------------------------------------------------===//
297// main for opt
298//
299int main(int argc, char **argv) {
300  sys::PrintStackTraceOnErrorSignal();
301  llvm::PrettyStackTraceProgram X(argc, argv);
302
303  // Enable debug stream buffering.
304  EnableDebugBuffering = true;
305
306  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
307  LLVMContext &Context = getGlobalContext();
308
309  InitializeAllTargets();
310  InitializeAllTargetMCs();
311  InitializeAllAsmPrinters();
312
313  // Initialize passes
314  PassRegistry &Registry = *PassRegistry::getPassRegistry();
315  initializeCore(Registry);
316  initializeScalarOpts(Registry);
317  initializeObjCARCOpts(Registry);
318  initializeVectorization(Registry);
319  initializeIPO(Registry);
320  initializeAnalysis(Registry);
321  initializeTransformUtils(Registry);
322  initializeInstCombine(Registry);
323  initializeInstrumentation(Registry);
324  initializeTarget(Registry);
325  // For codegen passes, only passes that do IR to IR transformation are
326  // supported.
327  initializeCodeGenPreparePass(Registry);
328  initializeAtomicExpandPass(Registry);
329  initializeRewriteSymbolsPass(Registry);
330  initializeWinEHPreparePass(Registry);
331  initializeDwarfEHPreparePass(Registry);
332  initializeSjLjEHPreparePass(Registry);
333
334#ifdef LINK_POLLY_INTO_TOOLS
335  polly::initializePollyPasses(Registry);
336#endif
337
338  cl::ParseCommandLineOptions(argc, argv,
339    "llvm .bc -> .bc modular optimizer and analysis printer\n");
340
341  if (AnalyzeOnly && NoOutput) {
342    errs() << argv[0] << ": analyze mode conflicts with no-output mode.\n";
343    return 1;
344  }
345
346  SMDiagnostic Err;
347
348  // Load the input module...
349  std::unique_ptr<Module> M = parseIRFile(InputFilename, Err, Context);
350
351  if (!M) {
352    Err.print(argv[0], errs());
353    return 1;
354  }
355
356  // Strip debug info before running the verifier.
357  if (StripDebug)
358    StripDebugInfo(*M);
359
360  // Immediately run the verifier to catch any problems before starting up the
361  // pass pipelines.  Otherwise we can crash on broken code during
362  // doInitialization().
363  if (!NoVerify && verifyModule(*M, &errs())) {
364    errs() << argv[0] << ": " << InputFilename
365           << ": error: input module is broken!\n";
366    return 1;
367  }
368
369  // If we are supposed to override the target triple, do so now.
370  if (!TargetTriple.empty())
371    M->setTargetTriple(Triple::normalize(TargetTriple));
372
373  // Figure out what stream we are supposed to write to...
374  std::unique_ptr<tool_output_file> Out;
375  if (NoOutput) {
376    if (!OutputFilename.empty())
377      errs() << "WARNING: The -o (output filename) option is ignored when\n"
378                "the --disable-output option is used.\n";
379  } else {
380    // Default to standard output.
381    if (OutputFilename.empty())
382      OutputFilename = "-";
383
384    std::error_code EC;
385    Out.reset(new tool_output_file(OutputFilename, EC, sys::fs::F_None));
386    if (EC) {
387      errs() << EC.message() << '\n';
388      return 1;
389    }
390  }
391
392  Triple ModuleTriple(M->getTargetTriple());
393  std::string CPUStr, FeaturesStr;
394  TargetMachine *Machine = nullptr;
395  const TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
396
397  if (ModuleTriple.getArch()) {
398    CPUStr = getCPUStr();
399    FeaturesStr = getFeaturesStr();
400    Machine = GetTargetMachine(ModuleTriple, CPUStr, FeaturesStr, Options);
401  }
402
403  std::unique_ptr<TargetMachine> TM(Machine);
404
405  // Override function attributes based on CPUStr, FeaturesStr, and command line
406  // flags.
407  setFunctionAttributes(CPUStr, FeaturesStr, *M);
408
409  // If the output is set to be emitted to standard out, and standard out is a
410  // console, print out a warning message and refuse to do it.  We don't
411  // impress anyone by spewing tons of binary goo to a terminal.
412  if (!Force && !NoOutput && !AnalyzeOnly && !OutputAssembly)
413    if (CheckBitcodeOutputToConsole(Out->os(), !Quiet))
414      NoOutput = true;
415
416  if (PassPipeline.getNumOccurrences() > 0) {
417    OutputKind OK = OK_NoOutput;
418    if (!NoOutput)
419      OK = OutputAssembly ? OK_OutputAssembly : OK_OutputBitcode;
420
421    VerifierKind VK = VK_VerifyInAndOut;
422    if (NoVerify)
423      VK = VK_NoVerifier;
424    else if (VerifyEach)
425      VK = VK_VerifyEachPass;
426
427    // The user has asked to use the new pass manager and provided a pipeline
428    // string. Hand off the rest of the functionality to the new code for that
429    // layer.
430    return runPassPipeline(argv[0], Context, *M, TM.get(), Out.get(),
431                           PassPipeline, OK, VK, PreserveAssemblyUseListOrder,
432                           PreserveBitcodeUseListOrder)
433               ? 0
434               : 1;
435  }
436
437  // Create a PassManager to hold and optimize the collection of passes we are
438  // about to build.
439  //
440  legacy::PassManager Passes;
441
442  // Add an appropriate TargetLibraryInfo pass for the module's triple.
443  TargetLibraryInfoImpl TLII(ModuleTriple);
444
445  // The -disable-simplify-libcalls flag actually disables all builtin optzns.
446  if (DisableSimplifyLibCalls)
447    TLII.disableAllFunctions();
448  Passes.add(new TargetLibraryInfoWrapperPass(TLII));
449
450  // Add an appropriate DataLayout instance for this module.
451  const DataLayout &DL = M->getDataLayout();
452  if (DL.isDefault() && !DefaultDataLayout.empty()) {
453    M->setDataLayout(DefaultDataLayout);
454  }
455
456  // Add internal analysis passes from the target machine.
457  Passes.add(createTargetTransformInfoWrapperPass(TM ? TM->getTargetIRAnalysis()
458                                                     : TargetIRAnalysis()));
459
460  std::unique_ptr<legacy::FunctionPassManager> FPasses;
461  if (OptLevelO1 || OptLevelO2 || OptLevelOs || OptLevelOz || OptLevelO3) {
462    FPasses.reset(new legacy::FunctionPassManager(M.get()));
463    FPasses->add(createTargetTransformInfoWrapperPass(
464        TM ? TM->getTargetIRAnalysis() : TargetIRAnalysis()));
465  }
466
467  if (PrintBreakpoints) {
468    // Default to standard output.
469    if (!Out) {
470      if (OutputFilename.empty())
471        OutputFilename = "-";
472
473      std::error_code EC;
474      Out = llvm::make_unique<tool_output_file>(OutputFilename, EC,
475                                                sys::fs::F_None);
476      if (EC) {
477        errs() << EC.message() << '\n';
478        return 1;
479      }
480    }
481    Passes.add(createBreakpointPrinter(Out->os()));
482    NoOutput = true;
483  }
484
485  // Create a new optimization pass for each one specified on the command line
486  for (unsigned i = 0; i < PassList.size(); ++i) {
487    if (StandardLinkOpts &&
488        StandardLinkOpts.getPosition() < PassList.getPosition(i)) {
489      AddStandardLinkPasses(Passes);
490      StandardLinkOpts = false;
491    }
492
493    if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
494      AddOptimizationPasses(Passes, *FPasses, 1, 0);
495      OptLevelO1 = false;
496    }
497
498    if (OptLevelO2 && OptLevelO2.getPosition() < PassList.getPosition(i)) {
499      AddOptimizationPasses(Passes, *FPasses, 2, 0);
500      OptLevelO2 = false;
501    }
502
503    if (OptLevelOs && OptLevelOs.getPosition() < PassList.getPosition(i)) {
504      AddOptimizationPasses(Passes, *FPasses, 2, 1);
505      OptLevelOs = false;
506    }
507
508    if (OptLevelOz && OptLevelOz.getPosition() < PassList.getPosition(i)) {
509      AddOptimizationPasses(Passes, *FPasses, 2, 2);
510      OptLevelOz = false;
511    }
512
513    if (OptLevelO3 && OptLevelO3.getPosition() < PassList.getPosition(i)) {
514      AddOptimizationPasses(Passes, *FPasses, 3, 0);
515      OptLevelO3 = false;
516    }
517
518    const PassInfo *PassInf = PassList[i];
519    Pass *P = nullptr;
520    if (PassInf->getTargetMachineCtor())
521      P = PassInf->getTargetMachineCtor()(TM.get());
522    else if (PassInf->getNormalCtor())
523      P = PassInf->getNormalCtor()();
524    else
525      errs() << argv[0] << ": cannot create pass: "
526             << PassInf->getPassName() << "\n";
527    if (P) {
528      PassKind Kind = P->getPassKind();
529      addPass(Passes, P);
530
531      if (AnalyzeOnly) {
532        switch (Kind) {
533        case PT_BasicBlock:
534          Passes.add(createBasicBlockPassPrinter(PassInf, Out->os(), Quiet));
535          break;
536        case PT_Region:
537          Passes.add(createRegionPassPrinter(PassInf, Out->os(), Quiet));
538          break;
539        case PT_Loop:
540          Passes.add(createLoopPassPrinter(PassInf, Out->os(), Quiet));
541          break;
542        case PT_Function:
543          Passes.add(createFunctionPassPrinter(PassInf, Out->os(), Quiet));
544          break;
545        case PT_CallGraphSCC:
546          Passes.add(createCallGraphPassPrinter(PassInf, Out->os(), Quiet));
547          break;
548        default:
549          Passes.add(createModulePassPrinter(PassInf, Out->os(), Quiet));
550          break;
551        }
552      }
553    }
554
555    if (PrintEachXForm)
556      Passes.add(
557          createPrintModulePass(errs(), "", PreserveAssemblyUseListOrder));
558  }
559
560  if (StandardLinkOpts) {
561    AddStandardLinkPasses(Passes);
562    StandardLinkOpts = false;
563  }
564
565  if (OptLevelO1)
566    AddOptimizationPasses(Passes, *FPasses, 1, 0);
567
568  if (OptLevelO2)
569    AddOptimizationPasses(Passes, *FPasses, 2, 0);
570
571  if (OptLevelOs)
572    AddOptimizationPasses(Passes, *FPasses, 2, 1);
573
574  if (OptLevelOz)
575    AddOptimizationPasses(Passes, *FPasses, 2, 2);
576
577  if (OptLevelO3)
578    AddOptimizationPasses(Passes, *FPasses, 3, 0);
579
580  if (OptLevelO1 || OptLevelO2 || OptLevelOs || OptLevelOz || OptLevelO3) {
581    FPasses->doInitialization();
582    for (Function &F : *M)
583      FPasses->run(F);
584    FPasses->doFinalization();
585  }
586
587  // Check that the module is well formed on completion of optimization
588  if (!NoVerify && !VerifyEach)
589    Passes.add(createVerifierPass());
590
591  // In run twice mode, we want to make sure the output is bit-by-bit
592  // equivalent if we run the pass manager again, so setup two buffers and
593  // a stream to write to them. Note that llc does something similar and it
594  // may be worth to abstract this out in the future.
595  SmallVector<char, 0> Buffer;
596  SmallVector<char, 0> CompileTwiceBuffer;
597  std::unique_ptr<raw_svector_ostream> BOS;
598  raw_ostream *OS = nullptr;
599
600  // Write bitcode or assembly to the output as the last step...
601  if (!NoOutput && !AnalyzeOnly) {
602    assert(Out);
603    OS = &Out->os();
604    if (RunTwice) {
605      BOS = make_unique<raw_svector_ostream>(Buffer);
606      OS = BOS.get();
607    }
608    if (OutputAssembly)
609      Passes.add(createPrintModulePass(*OS, "", PreserveAssemblyUseListOrder));
610    else
611      Passes.add(createBitcodeWriterPass(*OS, PreserveBitcodeUseListOrder));
612  }
613
614  // Before executing passes, print the final values of the LLVM options.
615  cl::PrintOptionValues();
616
617  // If requested, run all passes again with the same pass manager to catch
618  // bugs caused by persistent state in the passes
619  if (RunTwice) {
620      std::unique_ptr<Module> M2(CloneModule(M.get()));
621      Passes.run(*M2);
622      CompileTwiceBuffer = Buffer;
623      Buffer.clear();
624  }
625
626  // Now that we have all of the passes ready, run them.
627  Passes.run(*M);
628
629  // Compare the two outputs and make sure they're the same
630  if (RunTwice) {
631    assert(Out);
632    if (Buffer.size() != CompileTwiceBuffer.size() ||
633        (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
634         0)) {
635      errs() << "Running the pass manager twice changed the output.\n"
636                "Writing the result of the second run to the specified output.\n"
637                "To generate the one-run comparison binary, just run without\n"
638                "the compile-twice option\n";
639      Out->os() << BOS->str();
640      Out->keep();
641      return 1;
642    }
643    Out->os() << BOS->str();
644  }
645
646  // Declare success.
647  if (!NoOutput || PrintBreakpoints)
648    Out->keep();
649
650  return 0;
651}
652