tools/bugpoint/CrashDebugger.cpp

   1 //===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
   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 file defines the bugpoint internals that narrow down compilation crashes
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "BugDriver.h"
  15 #include "ToolRunner.h"
  16 #include "ListReducer.h"
  17 #include "llvm/Constants.h"
  18 #include "llvm/DerivedTypes.h"
  19 #include "llvm/Instructions.h"
  20 #include "llvm/Module.h"
  21 #include "llvm/Pass.h"
  22 #include "llvm/PassManager.h"
  23 #include "llvm/ValueSymbolTable.h"
  24 #include "llvm/ADT/SmallPtrSet.h"
  25 #include "llvm/Analysis/Verifier.h"
  26 #include "llvm/Support/CFG.h"
  27 #include "llvm/Transforms/Scalar.h"
  28 #include "llvm/Transforms/Utils/Cloning.h"
  29 #include "llvm/Support/FileUtilities.h"
  30 #include "llvm/Support/CommandLine.h"
  31 #include <set>
  32 using namespace llvm;
  33
  34 namespace {
  35   cl::opt<bool>
  36   KeepMain("keep-main",
  37            cl::desc("Force function reduction to keep main"),
  38            cl::init(false));
  39   cl::opt<bool>
  40   NoGlobalRM ("disable-global-remove",
  41          cl::desc("Do not remove global variables"),
  42          cl::init(false));
  43 }
  44
  45 namespace llvm {
  46   class ReducePassList : public ListReducer<const PassInfo*> {
  47     BugDriver &BD;
  48   public:
  49     ReducePassList(BugDriver &bd) : BD(bd) {}
  50
  51     // doTest - Return true iff running the "removed" passes succeeds, and
  52     // running the "Kept" passes fail when run on the output of the "removed"
  53     // passes.  If we return true, we update the current module of bugpoint.
  54     //
  55     virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
  56                               std::vector<const PassInfo*> &Kept);
  57   };
  58 }
  59
  60 ReducePassList::TestResult
  61 ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
  62                        std::vector<const PassInfo*> &Suffix) {
  63   sys::Path PrefixOutput;
  64   Module *OrigProgram = 0;
  65   if (!Prefix.empty()) {
  66     outs() << "Checking to see if these passes crash: "
  67            << getPassesString(Prefix) << ": ";
  68     std::string PfxOutput;
  69     if (BD.runPasses(Prefix, PfxOutput))
  70       return KeepPrefix;
  71
  72     PrefixOutput.set(PfxOutput);
  73     OrigProgram = BD.Program;
  74
  75     BD.Program = ParseInputFile(PrefixOutput.str(), BD.getContext());
  76     if (BD.Program == 0) {
  77       errs() << BD.getToolName() << ": Error reading bitcode file '"
  78              << PrefixOutput.str() << "'!\n";
  79       exit(1);
  80     }
  81     PrefixOutput.eraseFromDisk();
  82   }
  83
  84   outs() << "Checking to see if these passes crash: "
  85          << getPassesString(Suffix) << ": ";
  86
  87   if (BD.runPasses(Suffix)) {
  88     delete OrigProgram;            // The suffix crashes alone...
  89     return KeepSuffix;
  90   }
  91
  92   // Nothing failed, restore state...
  93   if (OrigProgram) {
  94     delete BD.Program;
  95     BD.Program = OrigProgram;
  96   }
  97   return NoFailure;
  98 }
  99
 100 namespace {
 101   /// ReduceCrashingGlobalVariables - This works by removing the global
 102   /// variable's initializer and seeing if the program still crashes. If it
 103   /// does, then we keep that program and try again.
 104   ///
 105   class ReduceCrashingGlobalVariables : public ListReducer<GlobalVariable*> {
 106     BugDriver &BD;
 107     bool (*TestFn)(BugDriver &, Module *);
 108   public:
 109     ReduceCrashingGlobalVariables(BugDriver &bd,
 110                                   bool (*testFn)(BugDriver&, Module*))
 111       : BD(bd), TestFn(testFn) {}
 112
 113     virtual TestResult doTest(std::vector<GlobalVariable*>& Prefix,
 114                               std::vector<GlobalVariable*>& Kept) {
 115       if (!Kept.empty() && TestGlobalVariables(Kept))
 116         return KeepSuffix;
 117
 118       if (!Prefix.empty() && TestGlobalVariables(Prefix))
 119         return KeepPrefix;
 120
 121       return NoFailure;
 122     }
 123
 124     bool TestGlobalVariables(std::vector<GlobalVariable*>& GVs);
 125   };
 126 }
 127
 128 bool
 129 ReduceCrashingGlobalVariables::TestGlobalVariables(
 130                               std::vector<GlobalVariable*>& GVs) {
 131   // Clone the program to try hacking it apart...
 132   DenseMap<const Value*, Value*> ValueMap;
 133   Module *M = CloneModule(BD.getProgram(), ValueMap);
 134
 135   // Convert list to set for fast lookup...
 136   std::set<GlobalVariable*> GVSet;
 137
 138   for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
 139     GlobalVariable* CMGV = cast<GlobalVariable>(ValueMap[GVs[i]]);
 140     assert(CMGV && "Global Variable not in module?!");
 141     GVSet.insert(CMGV);
 142   }
 143
 144   outs() << "Checking for crash with only these global variables: ";
 145   PrintGlobalVariableList(GVs);
 146   outs() << ": ";
 147
 148   // Loop over and delete any global variables which we aren't supposed to be
 149   // playing with...
 150   for (Module::global_iterator I = M->global_begin(), E = M->global_end();
 151        I != E; ++I)
 152     if (I->hasInitializer() && !GVSet.count(I)) {
 153       I->setInitializer(0);
 154       I->setLinkage(GlobalValue::ExternalLinkage);
 155     }
 156
 157   // Try running the hacked up program...
 158   if (TestFn(BD, M)) {
 159     BD.setNewProgram(M);        // It crashed, keep the trimmed version...
 160
 161     // Make sure to use global variable pointers that point into the now-current
 162     // module.
 163     GVs.assign(GVSet.begin(), GVSet.end());
 164     return true;
 165   }
 166
 167   delete M;
 168   return false;
 169 }
 170
 171 namespace llvm {
 172   /// ReduceCrashingFunctions reducer - This works by removing functions and
 173   /// seeing if the program still crashes. If it does, then keep the newer,
 174   /// smaller program.
 175   ///
 176   class ReduceCrashingFunctions : public ListReducer<Function*> {
 177     BugDriver &BD;
 178     bool (*TestFn)(BugDriver &, Module *);
 179   public:
 180     ReduceCrashingFunctions(BugDriver &bd,
 181                             bool (*testFn)(BugDriver &, Module *))
 182       : BD(bd), TestFn(testFn) {}
 183
 184     virtual TestResult doTest(std::vector<Function*> &Prefix,
 185                               std::vector<Function*> &Kept) {
 186       if (!Kept.empty() && TestFuncs(Kept))
 187         return KeepSuffix;
 188       if (!Prefix.empty() && TestFuncs(Prefix))
 189         return KeepPrefix;
 190       return NoFailure;
 191     }
 192
 193     bool TestFuncs(std::vector<Function*> &Prefix);
 194   };
 195 }
 196
 197 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
 198
 199   //if main isn't present, claim there is no problem
 200   if (KeepMain && find(Funcs.begin(), Funcs.end(),
 201                        BD.getProgram()->getFunction("main")) == Funcs.end())
 202     return false;
 203
 204   // Clone the program to try hacking it apart...
 205   DenseMap<const Value*, Value*> ValueMap;
 206   Module *M = CloneModule(BD.getProgram(), ValueMap);
 207
 208   // Convert list to set for fast lookup...
 209   std::set<Function*> Functions;
 210   for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
 211     Function *CMF = cast<Function>(ValueMap[Funcs[i]]);
 212     assert(CMF && "Function not in module?!");
 213     assert(CMF->getFunctionType() == Funcs[i]->getFunctionType() && "wrong ty");
 214     assert(CMF->getName() == Funcs[i]->getName() && "wrong name");
 215     Functions.insert(CMF);
 216   }
 217
 218   outs() << "Checking for crash with only these functions: ";
 219   PrintFunctionList(Funcs);
 220   outs() << ": ";
 221
 222   // Loop over and delete any functions which we aren't supposed to be playing
 223   // with...
 224   for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
 225     if (!I->isDeclaration() && !Functions.count(I))
 226       DeleteFunctionBody(I);
 227
 228   // Try running the hacked up program...
 229   if (TestFn(BD, M)) {
 230     BD.setNewProgram(M);        // It crashed, keep the trimmed version...
 231
 232     // Make sure to use function pointers that point into the now-current
 233     // module.
 234     Funcs.assign(Functions.begin(), Functions.end());
 235     return true;
 236   }
 237   delete M;
 238   return false;
 239 }
 240
 241
 242 namespace {
 243   /// ReduceCrashingBlocks reducer - This works by setting the terminators of
 244   /// all terminators except the specified basic blocks to a 'ret' instruction,
 245   /// then running the simplify-cfg pass.  This has the effect of chopping up
 246   /// the CFG really fast which can reduce large functions quickly.
 247   ///
 248   class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
 249     BugDriver &BD;
 250     bool (*TestFn)(BugDriver &, Module *);
 251   public:
 252     ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
 253       : BD(bd), TestFn(testFn) {}
 254
 255     virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
 256                               std::vector<const BasicBlock*> &Kept) {
 257       if (!Kept.empty() && TestBlocks(Kept))
 258         return KeepSuffix;
 259       if (!Prefix.empty() && TestBlocks(Prefix))
 260         return KeepPrefix;
 261       return NoFailure;
 262     }
 263
 264     bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
 265   };
 266 }
 267
 268 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
 269   // Clone the program to try hacking it apart...
 270   DenseMap<const Value*, Value*> ValueMap;
 271   Module *M = CloneModule(BD.getProgram(), ValueMap);
 272
 273   // Convert list to set for fast lookup...
 274   SmallPtrSet<BasicBlock*, 8> Blocks;
 275   for (unsigned i = 0, e = BBs.size(); i != e; ++i)
 276     Blocks.insert(cast<BasicBlock>(ValueMap[BBs[i]]));
 277
 278   outs() << "Checking for crash with only these blocks:";
 279   unsigned NumPrint = Blocks.size();
 280   if (NumPrint > 10) NumPrint = 10;
 281   for (unsigned i = 0, e = NumPrint; i != e; ++i)
 282     outs() << " " << BBs[i]->getName();
 283   if (NumPrint < Blocks.size())
 284     outs() << "... <" << Blocks.size() << " total>";
 285   outs() << ": ";
 286
 287   // Loop over and delete any hack up any blocks that are not listed...
 288   for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
 289     for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
 290       if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
 291         // Loop over all of the successors of this block, deleting any PHI nodes
 292         // that might include it.
 293         for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
 294           (*SI)->removePredecessor(BB);
 295
 296         TerminatorInst *BBTerm = BB->getTerminator();
 297
 298         if (isa<StructType>(BBTerm->getType()))
 299            BBTerm->replaceAllUsesWith(UndefValue::get(BBTerm->getType()));
 300         else if (BB->getTerminator()->getType() !=
 301                     Type::getVoidTy(BB->getContext()))
 302           BBTerm->replaceAllUsesWith(Constant::getNullValue(BBTerm->getType()));
 303
 304         // Replace the old terminator instruction.
 305         BB->getInstList().pop_back();
 306         new UnreachableInst(BB->getContext(), BB);
 307       }
 308
 309   // The CFG Simplifier pass may delete one of the basic blocks we are
 310   // interested in.  If it does we need to take the block out of the list.  Make
 311   // a "persistent mapping" by turning basic blocks into <function, name> pairs.
 312   // This won't work well if blocks are unnamed, but that is just the risk we
 313   // have to take.
 314   std::vector<std::pair<Function*, std::string> > BlockInfo;
 315
 316   for (SmallPtrSet<BasicBlock*, 8>::iterator I = Blocks.begin(),
 317          E = Blocks.end(); I != E; ++I)
 318     BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
 319
 320   // Now run the CFG simplify pass on the function...
 321   PassManager Passes;
 322   Passes.add(createCFGSimplificationPass());
 323   Passes.add(createVerifierPass());
 324   Passes.run(*M);
 325
 326   // Try running on the hacked up program...
 327   if (TestFn(BD, M)) {
 328     BD.setNewProgram(M);      // It crashed, keep the trimmed version...
 329
 330     // Make sure to use basic block pointers that point into the now-current
 331     // module, and that they don't include any deleted blocks.
 332     BBs.clear();
 333     for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
 334       ValueSymbolTable &ST = BlockInfo[i].first->getValueSymbolTable();
 335       Value* V = ST.lookup(BlockInfo[i].second);
 336       if (V && V->getType() == Type::getLabelTy(V->getContext()))
 337         BBs.push_back(cast<BasicBlock>(V));
 338     }
 339     return true;
 340   }
 341   delete M;  // It didn't crash, try something else.
 342   return false;
 343 }
 344
 345 namespace {
 346   /// ReduceCrashingInstructions reducer - This works by removing the specified
 347   /// non-terminator instructions and replacing them with undef.
 348   ///
 349   class ReduceCrashingInstructions : public ListReducer<const Instruction*> {
 350     BugDriver &BD;
 351     bool (*TestFn)(BugDriver &, Module *);
 352   public:
 353     ReduceCrashingInstructions(BugDriver &bd, bool (*testFn)(BugDriver &,
 354                                                              Module *))
 355       : BD(bd), TestFn(testFn) {}
 356
 357     virtual TestResult doTest(std::vector<const Instruction*> &Prefix,
 358                               std::vector<const Instruction*> &Kept) {
 359       if (!Kept.empty() && TestInsts(Kept))
 360         return KeepSuffix;
 361       if (!Prefix.empty() && TestInsts(Prefix))
 362         return KeepPrefix;
 363       return NoFailure;
 364     }
 365
 366     bool TestInsts(std::vector<const Instruction*> &Prefix);
 367   };
 368 }
 369
 370 bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
 371                                            &Insts) {
 372   // Clone the program to try hacking it apart...
 373   DenseMap<const Value*, Value*> ValueMap;
 374   Module *M = CloneModule(BD.getProgram(), ValueMap);
 375
 376   // Convert list to set for fast lookup...
 377   SmallPtrSet<Instruction*, 64> Instructions;
 378   for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
 379     assert(!isa<TerminatorInst>(Insts[i]));
 380     Instructions.insert(cast<Instruction>(ValueMap[Insts[i]]));
 381   }
 382
 383   outs() << "Checking for crash with only " << Instructions.size();
 384   if (Instructions.size() == 1)
 385     outs() << " instruction: ";
 386   else
 387     outs() << " instructions: ";
 388
 389   for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
 390     for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
 391       for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
 392         Instruction *Inst = I++;
 393         if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst)) {
 394           if (Inst->getType() != Type::getVoidTy(Inst->getContext()))
 395             Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
 396           Inst->eraseFromParent();
 397         }
 398       }
 399
 400   // Verify that this is still valid.
 401   PassManager Passes;
 402   Passes.add(createVerifierPass());
 403   Passes.run(*M);
 404
 405   // Try running on the hacked up program...
 406   if (TestFn(BD, M)) {
 407     BD.setNewProgram(M);      // It crashed, keep the trimmed version...
 408
 409     // Make sure to use instruction pointers that point into the now-current
 410     // module, and that they don't include any deleted blocks.
 411     Insts.clear();
 412     for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
 413              E = Instructions.end(); I != E; ++I)
 414       Insts.push_back(*I);
 415     return true;
 416   }
 417   delete M;  // It didn't crash, try something else.
 418   return false;
 419 }
 420
 421 /// DebugACrash - Given a predicate that determines whether a component crashes
 422 /// on a program, try to destructively reduce the program while still keeping
 423 /// the predicate true.
 424 static bool DebugACrash(BugDriver &BD,  bool (*TestFn)(BugDriver &, Module *)) {
 425   // See if we can get away with nuking some of the global variable initializers
 426   // in the program...
 427   if (!NoGlobalRM &&
 428       BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
 429     // Now try to reduce the number of global variable initializers in the
 430     // module to something small.
 431     Module *M = CloneModule(BD.getProgram());
 432     bool DeletedInit = false;
 433
 434     for (Module::global_iterator I = M->global_begin(), E = M->global_end();
 435          I != E; ++I)
 436       if (I->hasInitializer()) {
 437         I->setInitializer(0);
 438         I->setLinkage(GlobalValue::ExternalLinkage);
 439         DeletedInit = true;
 440       }
 441
 442     if (!DeletedInit) {
 443       delete M;  // No change made...
 444     } else {
 445       // See if the program still causes a crash...
 446       outs() << "\nChecking to see if we can delete global inits: ";
 447
 448       if (TestFn(BD, M)) {      // Still crashes?
 449         BD.setNewProgram(M);
 450         outs() << "\n*** Able to remove all global initializers!\n";
 451       } else {                  // No longer crashes?
 452         outs() << "  - Removing all global inits hides problem!\n";
 453         delete M;
 454
 455         std::vector<GlobalVariable*> GVs;
 456
 457         for (Module::global_iterator I = BD.getProgram()->global_begin(),
 458                E = BD.getProgram()->global_end(); I != E; ++I)
 459           if (I->hasInitializer())
 460             GVs.push_back(I);
 461
 462         if (GVs.size() > 1 && !BugpointIsInterrupted) {
 463           outs() << "\n*** Attempting to reduce the number of global "
 464                     << "variables in the testcase\n";
 465
 466           unsigned OldSize = GVs.size();
 467           ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs);
 468
 469           if (GVs.size() < OldSize)
 470             BD.EmitProgressBitcode("reduced-global-variables");
 471         }
 472       }
 473     }
 474   }
 475
 476   // Now try to reduce the number of functions in the module to something small.
 477   std::vector<Function*> Functions;
 478   for (Module::iterator I = BD.getProgram()->begin(),
 479          E = BD.getProgram()->end(); I != E; ++I)
 480     if (!I->isDeclaration())
 481       Functions.push_back(I);
 482
 483   if (Functions.size() > 1 && !BugpointIsInterrupted) {
 484     outs() << "\n*** Attempting to reduce the number of functions "
 485       "in the testcase\n";
 486
 487     unsigned OldSize = Functions.size();
 488     ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
 489
 490     if (Functions.size() < OldSize)
 491       BD.EmitProgressBitcode("reduced-function");
 492   }
 493
 494   // Attempt to delete entire basic blocks at a time to speed up
 495   // convergence... this actually works by setting the terminator of the blocks
 496   // to a return instruction then running simplifycfg, which can potentially
 497   // shrinks the code dramatically quickly
 498   //
 499   if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
 500     std::vector<const BasicBlock*> Blocks;
 501     for (Module::const_iterator I = BD.getProgram()->begin(),
 502            E = BD.getProgram()->end(); I != E; ++I)
 503       for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
 504         Blocks.push_back(FI);
 505     unsigned OldSize = Blocks.size();
 506     ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
 507     if (Blocks.size() < OldSize)
 508       BD.EmitProgressBitcode("reduced-blocks");
 509   }
 510
 511   // Attempt to delete instructions using bisection. This should help out nasty
 512   // cases with large basic blocks where the problem is at one end.
 513   if (!BugpointIsInterrupted) {
 514     std::vector<const Instruction*> Insts;
 515     for (Module::const_iterator MI = BD.getProgram()->begin(),
 516            ME = BD.getProgram()->end(); MI != ME; ++MI)
 517       for (Function::const_iterator FI = MI->begin(), FE = MI->end(); FI != FE;
 518            ++FI)
 519         for (BasicBlock::const_iterator I = FI->begin(), E = FI->end();
 520              I != E; ++I)
 521           if (!isa<TerminatorInst>(I))
 522             Insts.push_back(I);
 523
 524     ReduceCrashingInstructions(BD, TestFn).reduceList(Insts);
 525   }
 526
 527   // FIXME: This should use the list reducer to converge faster by deleting
 528   // larger chunks of instructions at a time!
 529   unsigned Simplification = 2;
 530   do {
 531     if (BugpointIsInterrupted) break;
 532     --Simplification;
 533     outs() << "\n*** Attempting to reduce testcase by deleting instruc"
 534            << "tions: Simplification Level #" << Simplification << '\n';
 535
 536     // Now that we have deleted the functions that are unnecessary for the
 537     // program, try to remove instructions that are not necessary to cause the
 538     // crash.  To do this, we loop through all of the instructions in the
 539     // remaining functions, deleting them (replacing any values produced with
 540     // nulls), and then running ADCE and SimplifyCFG.  If the transformed input
 541     // still triggers failure, keep deleting until we cannot trigger failure
 542     // anymore.
 543     //
 544     unsigned InstructionsToSkipBeforeDeleting = 0;
 545   TryAgain:
 546
 547     // Loop over all of the (non-terminator) instructions remaining in the
 548     // function, attempting to delete them.
 549     unsigned CurInstructionNum = 0;
 550     for (Module::const_iterator FI = BD.getProgram()->begin(),
 551            E = BD.getProgram()->end(); FI != E; ++FI)
 552       if (!FI->isDeclaration())
 553         for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
 554              ++BI)
 555           for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
 556                I != E; ++I, ++CurInstructionNum)
 557             if (InstructionsToSkipBeforeDeleting) {
 558               --InstructionsToSkipBeforeDeleting;
 559             } else {
 560               if (BugpointIsInterrupted) goto ExitLoops;
 561
 562               outs() << "Checking instruction: " << *I;
 563               Module *M = BD.deleteInstructionFromProgram(I, Simplification);
 564
 565               // Find out if the pass still crashes on this pass...
 566               if (TestFn(BD, M)) {
 567                 // Yup, it does, we delete the old module, and continue trying
 568                 // to reduce the testcase...
 569                 BD.setNewProgram(M);
 570                 InstructionsToSkipBeforeDeleting = CurInstructionNum;
 571                 goto TryAgain;  // I wish I had a multi-level break here!
 572               }
 573
 574               // This pass didn't crash without this instruction, try the next
 575               // one.
 576               delete M;
 577             }
 578
 579     if (InstructionsToSkipBeforeDeleting) {
 580       InstructionsToSkipBeforeDeleting = 0;
 581       goto TryAgain;
 582     }
 583
 584   } while (Simplification);
 585 ExitLoops:
 586
 587   // Try to clean up the testcase by running funcresolve and globaldce...
 588   if (!BugpointIsInterrupted) {
 589     outs() << "\n*** Attempting to perform final cleanups: ";
 590     Module *M = CloneModule(BD.getProgram());
 591     M = BD.performFinalCleanups(M, true);
 592
 593     // Find out if the pass still crashes on the cleaned up program...
 594     if (TestFn(BD, M)) {
 595       BD.setNewProgram(M);     // Yup, it does, keep the reduced version...
 596     } else {
 597       delete M;
 598     }
 599   }
 600
 601   BD.EmitProgressBitcode("reduced-simplified");
 602
 603   return false;
 604 }
 605
 606 static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
 607   return BD.runPasses(M);
 608 }
 609
 610 /// debugOptimizerCrash - This method is called when some pass crashes on input.
 611 /// It attempts to prune down the testcase to something reasonable, and figure
 612 /// out exactly which pass is crashing.
 613 ///
 614 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
 615   outs() << "\n*** Debugging optimizer crash!\n";
 616
 617   // Reduce the list of passes which causes the optimizer to crash...
 618   if (!BugpointIsInterrupted)
 619     ReducePassList(*this).reduceList(PassesToRun);
 620
 621   outs() << "\n*** Found crashing pass"
 622          << (PassesToRun.size() == 1 ? ": " : "es: ")
 623          << getPassesString(PassesToRun) << '\n';
 624
 625   EmitProgressBitcode(ID);
 626
 627   return DebugACrash(*this, TestForOptimizerCrash);
 628 }
 629
 630 static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
 631   try {
 632     BD.compileProgram(M);
 633     errs() << '\n';
 634     return false;
 635   } catch (ToolExecutionError &) {
 636     errs() << "<crash>\n";
 637     return true;  // Tool is still crashing.
 638   }
 639 }
 640
 641 /// debugCodeGeneratorCrash - This method is called when the code generator
 642 /// crashes on an input.  It attempts to reduce the input as much as possible
 643 /// while still causing the code generator to crash.
 644 bool BugDriver::debugCodeGeneratorCrash() {
 645   errs() << "*** Debugging code generator crash!\n";
 646
 647   return DebugACrash(*this, TestForCodeGenCrash);
 648 }