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 <iostream>
  32 #include <fstream>
  33 #include <set>
  34 using namespace llvm;
  35
  36 namespace {
  37   cl::opt<bool>
  38   KeepMain("keep-main",
  39            cl::desc("Force function reduction to keep main"),
  40            cl::init(false));
  41   cl::opt<bool>
  42   NoGlobalRM ("disable-global-remove",
  43          cl::desc("Do not remove global variables"),
  44          cl::init(false));
  45 }
  46
  47 namespace llvm {
  48   class ReducePassList : public ListReducer<const PassInfo*> {
  49     BugDriver &BD;
  50   public:
  51     ReducePassList(BugDriver &bd) : BD(bd) {}
  52
  53     // doTest - Return true iff running the "removed" passes succeeds, and
  54     // running the "Kept" passes fail when run on the output of the "removed"
  55     // passes.  If we return true, we update the current module of bugpoint.
  56     //
  57     virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
  58                               std::vector<const PassInfo*> &Kept);
  59   };
  60 }
  61
  62 ReducePassList::TestResult
  63 ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
  64                        std::vector<const PassInfo*> &Suffix) {
  65   sys::Path PrefixOutput;
  66   Module *OrigProgram = 0;
  67   if (!Prefix.empty()) {
  68     std::cout << "Checking to see if these passes crash: "
  69               << getPassesString(Prefix) << ": ";
  70     std::string PfxOutput;
  71     if (BD.runPasses(Prefix, PfxOutput))
  72       return KeepPrefix;
  73
  74     PrefixOutput.set(PfxOutput);
  75     OrigProgram = BD.Program;
  76
  77     BD.Program = ParseInputFile(PrefixOutput.toString(), BD.getContext());
  78     if (BD.Program == 0) {
  79       errs() << BD.getToolName() << ": Error reading bitcode file '"
  80              << PrefixOutput << "'!\n";
  81       exit(1);
  82     }
  83     PrefixOutput.eraseFromDisk();
  84   }
  85
  86   std::cout << "Checking to see if these passes crash: "
  87             << getPassesString(Suffix) << ": ";
  88
  89   if (BD.runPasses(Suffix)) {
  90     delete OrigProgram;            // The suffix crashes alone...
  91     return KeepSuffix;
  92   }
  93
  94   // Nothing failed, restore state...
  95   if (OrigProgram) {
  96     delete BD.Program;
  97     BD.Program = OrigProgram;
  98   }
  99   return NoFailure;
 100 }
 101
 102 namespace {
 103   /// ReduceCrashingGlobalVariables - This works by removing the global
 104   /// variable's initializer and seeing if the program still crashes. If it
 105   /// does, then we keep that program and try again.
 106   ///
 107   class ReduceCrashingGlobalVariables : public ListReducer<GlobalVariable*> {
 108     BugDriver &BD;
 109     bool (*TestFn)(BugDriver &, Module *);
 110   public:
 111     ReduceCrashingGlobalVariables(BugDriver &bd,
 112                                   bool (*testFn)(BugDriver&, Module*))
 113       : BD(bd), TestFn(testFn) {}
 114
 115     virtual TestResult doTest(std::vector<GlobalVariable*>& Prefix,
 116                               std::vector<GlobalVariable*>& Kept) {
 117       if (!Kept.empty() && TestGlobalVariables(Kept))
 118         return KeepSuffix;
 119
 120       if (!Prefix.empty() && TestGlobalVariables(Prefix))
 121         return KeepPrefix;
 122
 123       return NoFailure;
 124     }
 125
 126     bool TestGlobalVariables(std::vector<GlobalVariable*>& GVs);
 127   };
 128 }
 129
 130 bool
 131 ReduceCrashingGlobalVariables::TestGlobalVariables(
 132                               std::vector<GlobalVariable*>& GVs) {
 133   // Clone the program to try hacking it apart...
 134   DenseMap<const Value*, Value*> ValueMap;
 135   Module *M = CloneModule(BD.getProgram(), ValueMap);
 136
 137   // Convert list to set for fast lookup...
 138   std::set<GlobalVariable*> GVSet;
 139
 140   for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
 141     GlobalVariable* CMGV = cast<GlobalVariable>(ValueMap[GVs[i]]);
 142     assert(CMGV && "Global Variable not in module?!");
 143     GVSet.insert(CMGV);
 144   }
 145
 146   std::cout << "Checking for crash with only these global variables: ";
 147   PrintGlobalVariableList(GVs);
 148   std::cout << ": ";
 149
 150   // Loop over and delete any global variables which we aren't supposed to be
 151   // playing with...
 152   for (Module::global_iterator I = M->global_begin(), E = M->global_end();
 153        I != E; ++I)
 154     if (I->hasInitializer() && !GVSet.count(I)) {
 155       I->setInitializer(0);
 156       I->setLinkage(GlobalValue::ExternalLinkage);
 157     }
 158
 159   // Try running the hacked up program...
 160   if (TestFn(BD, M)) {
 161     BD.setNewProgram(M);        // It crashed, keep the trimmed version...
 162
 163     // Make sure to use global variable pointers that point into the now-current
 164     // module.
 165     GVs.assign(GVSet.begin(), GVSet.end());
 166     return true;
 167   }
 168
 169   delete M;
 170   return false;
 171 }
 172
 173 namespace llvm {
 174   /// ReduceCrashingFunctions reducer - This works by removing functions and
 175   /// seeing if the program still crashes. If it does, then keep the newer,
 176   /// smaller program.
 177   ///
 178   class ReduceCrashingFunctions : public ListReducer<Function*> {
 179     BugDriver &BD;
 180     bool (*TestFn)(BugDriver &, Module *);
 181   public:
 182     ReduceCrashingFunctions(BugDriver &bd,
 183                             bool (*testFn)(BugDriver &, Module *))
 184       : BD(bd), TestFn(testFn) {}
 185
 186     virtual TestResult doTest(std::vector<Function*> &Prefix,
 187                               std::vector<Function*> &Kept) {
 188       if (!Kept.empty() && TestFuncs(Kept))
 189         return KeepSuffix;
 190       if (!Prefix.empty() && TestFuncs(Prefix))
 191         return KeepPrefix;
 192       return NoFailure;
 193     }
 194
 195     bool TestFuncs(std::vector<Function*> &Prefix);
 196   };
 197 }
 198
 199 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
 200
 201   //if main isn't present, claim there is no problem
 202   if (KeepMain && find(Funcs.begin(), Funcs.end(),
 203                        BD.getProgram()->getFunction("main")) == Funcs.end())
 204     return false;
 205
 206   // Clone the program to try hacking it apart...
 207   DenseMap<const Value*, Value*> ValueMap;
 208   Module *M = CloneModule(BD.getProgram(), ValueMap);
 209
 210   // Convert list to set for fast lookup...
 211   std::set<Function*> Functions;
 212   for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
 213     Function *CMF = cast<Function>(ValueMap[Funcs[i]]);
 214     assert(CMF && "Function not in module?!");
 215     assert(CMF->getFunctionType() == Funcs[i]->getFunctionType() && "wrong ty");
 216     assert(CMF->getName() == Funcs[i]->getName() && "wrong name");
 217     Functions.insert(CMF);
 218   }
 219
 220   std::cout << "Checking for crash with only these functions: ";
 221   PrintFunctionList(Funcs);
 222   std::cout << ": ";
 223
 224   // Loop over and delete any functions which we aren't supposed to be playing
 225   // with...
 226   for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
 227     if (!I->isDeclaration() && !Functions.count(I))
 228       DeleteFunctionBody(I);
 229
 230   // Try running the hacked up program...
 231   if (TestFn(BD, M)) {
 232     BD.setNewProgram(M);        // It crashed, keep the trimmed version...
 233
 234     // Make sure to use function pointers that point into the now-current
 235     // module.
 236     Funcs.assign(Functions.begin(), Functions.end());
 237     return true;
 238   }
 239   delete M;
 240   return false;
 241 }
 242
 243
 244 namespace {
 245   /// ReduceCrashingBlocks reducer - This works by setting the terminators of
 246   /// all terminators except the specified basic blocks to a 'ret' instruction,
 247   /// then running the simplify-cfg pass.  This has the effect of chopping up
 248   /// the CFG really fast which can reduce large functions quickly.
 249   ///
 250   class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
 251     BugDriver &BD;
 252     bool (*TestFn)(BugDriver &, Module *);
 253   public:
 254     ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
 255       : BD(bd), TestFn(testFn) {}
 256
 257     virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
 258                               std::vector<const BasicBlock*> &Kept) {
 259       if (!Kept.empty() && TestBlocks(Kept))
 260         return KeepSuffix;
 261       if (!Prefix.empty() && TestBlocks(Prefix))
 262         return KeepPrefix;
 263       return NoFailure;
 264     }
 265
 266     bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
 267   };
 268 }
 269
 270 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
 271   // Clone the program to try hacking it apart...
 272   DenseMap<const Value*, Value*> ValueMap;
 273   Module *M = CloneModule(BD.getProgram(), ValueMap);
 274
 275   // Convert list to set for fast lookup...
 276   SmallPtrSet<BasicBlock*, 8> Blocks;
 277   for (unsigned i = 0, e = BBs.size(); i != e; ++i)
 278     Blocks.insert(cast<BasicBlock>(ValueMap[BBs[i]]));
 279
 280   std::cout << "Checking for crash with only these blocks:";
 281   unsigned NumPrint = Blocks.size();
 282   if (NumPrint > 10) NumPrint = 10;
 283   for (unsigned i = 0, e = NumPrint; i != e; ++i)
 284     std::cout << " " << BBs[i]->getName();
 285   if (NumPrint < Blocks.size())
 286     std::cout << "... <" << Blocks.size() << " total>";
 287   std::cout << ": ";
 288
 289   // Loop over and delete any hack up any blocks that are not listed...
 290   for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
 291     for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
 292       if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
 293         // Loop over all of the successors of this block, deleting any PHI nodes
 294         // that might include it.
 295         for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
 296           (*SI)->removePredecessor(BB);
 297
 298         TerminatorInst *BBTerm = BB->getTerminator();
 299
 300         if (isa<StructType>(BBTerm->getType()))
 301            BBTerm->replaceAllUsesWith(UndefValue::get(BBTerm->getType()));
 302         else if (BB->getTerminator()->getType() != Type::VoidTy)
 303           BBTerm->replaceAllUsesWith(
 304                                BD.getContext().getNullValue(BBTerm->getType()));
 305
 306         // Replace the old terminator instruction.
 307         BB->getInstList().pop_back();
 308         new UnreachableInst(BB);
 309       }
 310
 311   // The CFG Simplifier pass may delete one of the basic blocks we are
 312   // interested in.  If it does we need to take the block out of the list.  Make
 313   // a "persistent mapping" by turning basic blocks into <function, name> pairs.
 314   // This won't work well if blocks are unnamed, but that is just the risk we
 315   // have to take.
 316   std::vector<std::pair<Function*, std::string> > BlockInfo;
 317
 318   for (SmallPtrSet<BasicBlock*, 8>::iterator I = Blocks.begin(),
 319          E = Blocks.end(); I != E; ++I)
 320     BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
 321
 322   // Now run the CFG simplify pass on the function...
 323   PassManager Passes;
 324   Passes.add(createCFGSimplificationPass());
 325   Passes.add(createVerifierPass());
 326   Passes.run(*M);
 327
 328   // Try running on the hacked up program...
 329   if (TestFn(BD, M)) {
 330     BD.setNewProgram(M);      // It crashed, keep the trimmed version...
 331
 332     // Make sure to use basic block pointers that point into the now-current
 333     // module, and that they don't include any deleted blocks.
 334     BBs.clear();
 335     for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
 336       ValueSymbolTable &ST = BlockInfo[i].first->getValueSymbolTable();
 337       Value* V = ST.lookup(BlockInfo[i].second);
 338       if (V && V->getType() == Type::LabelTy)
 339         BBs.push_back(cast<BasicBlock>(V));
 340     }
 341     return true;
 342   }
 343   delete M;  // It didn't crash, try something else.
 344   return false;
 345 }
 346
 347 namespace {
 348   /// ReduceCrashingInstructions reducer - This works by removing the specified
 349   /// non-terminator instructions and replacing them with undef.
 350   ///
 351   class ReduceCrashingInstructions : public ListReducer<const Instruction*> {
 352     BugDriver &BD;
 353     bool (*TestFn)(BugDriver &, Module *);
 354   public:
 355     ReduceCrashingInstructions(BugDriver &bd, bool (*testFn)(BugDriver &,
 356                                                              Module *))
 357       : BD(bd), TestFn(testFn) {}
 358
 359     virtual TestResult doTest(std::vector<const Instruction*> &Prefix,
 360                               std::vector<const Instruction*> &Kept) {
 361       if (!Kept.empty() && TestInsts(Kept))
 362         return KeepSuffix;
 363       if (!Prefix.empty() && TestInsts(Prefix))
 364         return KeepPrefix;
 365       return NoFailure;
 366     }
 367
 368     bool TestInsts(std::vector<const Instruction*> &Prefix);
 369   };
 370 }
 371
 372 bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
 373                                            &Insts) {
 374   // Clone the program to try hacking it apart...
 375   DenseMap<const Value*, Value*> ValueMap;
 376   Module *M = CloneModule(BD.getProgram(), ValueMap);
 377
 378   // Convert list to set for fast lookup...
 379   SmallPtrSet<Instruction*, 64> Instructions;
 380   for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
 381     assert(!isa<TerminatorInst>(Insts[i]));
 382     Instructions.insert(cast<Instruction>(ValueMap[Insts[i]]));
 383   }
 384
 385   std::cout << "Checking for crash with only " << Instructions.size();
 386   if (Instructions.size() == 1)
 387     std::cout << " instruction: ";
 388   else
 389     std::cout << " instructions: ";
 390
 391   for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
 392     for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
 393       for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
 394         Instruction *Inst = I++;
 395         if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst)) {
 396           if (Inst->getType() != Type::VoidTy)
 397             Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
 398           Inst->eraseFromParent();
 399         }
 400       }
 401
 402   // Verify that this is still valid.
 403   PassManager Passes;
 404   Passes.add(createVerifierPass());
 405   Passes.run(*M);
 406
 407   // Try running on the hacked up program...
 408   if (TestFn(BD, M)) {
 409     BD.setNewProgram(M);      // It crashed, keep the trimmed version...
 410
 411     // Make sure to use instruction pointers that point into the now-current
 412     // module, and that they don't include any deleted blocks.
 413     Insts.clear();
 414     for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
 415              E = Instructions.end(); I != E; ++I)
 416       Insts.push_back(*I);
 417     return true;
 418   }
 419   delete M;  // It didn't crash, try something else.
 420   return false;
 421 }
 422
 423 /// DebugACrash - Given a predicate that determines whether a component crashes
 424 /// on a program, try to destructively reduce the program while still keeping
 425 /// the predicate true.
 426 static bool DebugACrash(BugDriver &BD,  bool (*TestFn)(BugDriver &, Module *)) {
 427   // See if we can get away with nuking some of the global variable initializers
 428   // in the program...
 429   if (!NoGlobalRM &&
 430       BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
 431     // Now try to reduce the number of global variable initializers in the
 432     // module to something small.
 433     Module *M = CloneModule(BD.getProgram());
 434     bool DeletedInit = false;
 435
 436     for (Module::global_iterator I = M->global_begin(), E = M->global_end();
 437          I != E; ++I)
 438       if (I->hasInitializer()) {
 439         I->setInitializer(0);
 440         I->setLinkage(GlobalValue::ExternalLinkage);
 441         DeletedInit = true;
 442       }
 443
 444     if (!DeletedInit) {
 445       delete M;  // No change made...
 446     } else {
 447       // See if the program still causes a crash...
 448       std::cout << "\nChecking to see if we can delete global inits: ";
 449
 450       if (TestFn(BD, M)) {      // Still crashes?
 451         BD.setNewProgram(M);
 452         std::cout << "\n*** Able to remove all global initializers!\n";
 453       } else {                  // No longer crashes?
 454         std::cout << "  - Removing all global inits hides problem!\n";
 455         delete M;
 456
 457         std::vector<GlobalVariable*> GVs;
 458
 459         for (Module::global_iterator I = BD.getProgram()->global_begin(),
 460                E = BD.getProgram()->global_end(); I != E; ++I)
 461           if (I->hasInitializer())
 462             GVs.push_back(I);
 463
 464         if (GVs.size() > 1 && !BugpointIsInterrupted) {
 465           std::cout << "\n*** Attempting to reduce the number of global "
 466                     << "variables in the testcase\n";
 467
 468           unsigned OldSize = GVs.size();
 469           ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs);
 470
 471           if (GVs.size() < OldSize)
 472             BD.EmitProgressBitcode("reduced-global-variables");
 473         }
 474       }
 475     }
 476   }
 477
 478   // Now try to reduce the number of functions in the module to something small.
 479   std::vector<Function*> Functions;
 480   for (Module::iterator I = BD.getProgram()->begin(),
 481          E = BD.getProgram()->end(); I != E; ++I)
 482     if (!I->isDeclaration())
 483       Functions.push_back(I);
 484
 485   if (Functions.size() > 1 && !BugpointIsInterrupted) {
 486     std::cout << "\n*** Attempting to reduce the number of functions "
 487       "in the testcase\n";
 488
 489     unsigned OldSize = Functions.size();
 490     ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
 491
 492     if (Functions.size() < OldSize)
 493       BD.EmitProgressBitcode("reduced-function");
 494   }
 495
 496   // Attempt to delete entire basic blocks at a time to speed up
 497   // convergence... this actually works by setting the terminator of the blocks
 498   // to a return instruction then running simplifycfg, which can potentially
 499   // shrinks the code dramatically quickly
 500   //
 501   if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
 502     std::vector<const BasicBlock*> Blocks;
 503     for (Module::const_iterator I = BD.getProgram()->begin(),
 504            E = BD.getProgram()->end(); I != E; ++I)
 505       for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
 506         Blocks.push_back(FI);
 507     unsigned OldSize = Blocks.size();
 508     ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
 509     if (Blocks.size() < OldSize)
 510       BD.EmitProgressBitcode("reduced-blocks");
 511   }
 512
 513   // Attempt to delete instructions using bisection. This should help out nasty
 514   // cases with large basic blocks where the problem is at one end.
 515   if (!BugpointIsInterrupted) {
 516     std::vector<const Instruction*> Insts;
 517     for (Module::const_iterator MI = BD.getProgram()->begin(),
 518            ME = BD.getProgram()->end(); MI != ME; ++MI)
 519       for (Function::const_iterator FI = MI->begin(), FE = MI->end(); FI != FE;
 520            ++FI)
 521         for (BasicBlock::const_iterator I = FI->begin(), E = FI->end();
 522              I != E; ++I)
 523           if (!isa<TerminatorInst>(I))
 524             Insts.push_back(I);
 525
 526     ReduceCrashingInstructions(BD, TestFn).reduceList(Insts);
 527   }
 528
 529   // FIXME: This should use the list reducer to converge faster by deleting
 530   // larger chunks of instructions at a time!
 531   unsigned Simplification = 2;
 532   do {
 533     if (BugpointIsInterrupted) break;
 534     --Simplification;
 535     std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
 536               << "tions: Simplification Level #" << Simplification << '\n';
 537
 538     // Now that we have deleted the functions that are unnecessary for the
 539     // program, try to remove instructions that are not necessary to cause the
 540     // crash.  To do this, we loop through all of the instructions in the
 541     // remaining functions, deleting them (replacing any values produced with
 542     // nulls), and then running ADCE and SimplifyCFG.  If the transformed input
 543     // still triggers failure, keep deleting until we cannot trigger failure
 544     // anymore.
 545     //
 546     unsigned InstructionsToSkipBeforeDeleting = 0;
 547   TryAgain:
 548
 549     // Loop over all of the (non-terminator) instructions remaining in the
 550     // function, attempting to delete them.
 551     unsigned CurInstructionNum = 0;
 552     for (Module::const_iterator FI = BD.getProgram()->begin(),
 553            E = BD.getProgram()->end(); FI != E; ++FI)
 554       if (!FI->isDeclaration())
 555         for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
 556              ++BI)
 557           for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
 558                I != E; ++I, ++CurInstructionNum)
 559             if (InstructionsToSkipBeforeDeleting) {
 560               --InstructionsToSkipBeforeDeleting;
 561             } else {
 562               if (BugpointIsInterrupted) goto ExitLoops;
 563
 564               std::cout << "Checking instruction: " << *I;
 565               Module *M = BD.deleteInstructionFromProgram(I, Simplification);
 566
 567               // Find out if the pass still crashes on this pass...
 568               if (TestFn(BD, M)) {
 569                 // Yup, it does, we delete the old module, and continue trying
 570                 // to reduce the testcase...
 571                 BD.setNewProgram(M);
 572                 InstructionsToSkipBeforeDeleting = CurInstructionNum;
 573                 goto TryAgain;  // I wish I had a multi-level break here!
 574               }
 575
 576               // This pass didn't crash without this instruction, try the next
 577               // one.
 578               delete M;
 579             }
 580
 581     if (InstructionsToSkipBeforeDeleting) {
 582       InstructionsToSkipBeforeDeleting = 0;
 583       goto TryAgain;
 584     }
 585
 586   } while (Simplification);
 587 ExitLoops:
 588
 589   // Try to clean up the testcase by running funcresolve and globaldce...
 590   if (!BugpointIsInterrupted) {
 591     std::cout << "\n*** Attempting to perform final cleanups: ";
 592     Module *M = CloneModule(BD.getProgram());
 593     M = BD.performFinalCleanups(M, true);
 594
 595     // Find out if the pass still crashes on the cleaned up program...
 596     if (TestFn(BD, M)) {
 597       BD.setNewProgram(M);     // Yup, it does, keep the reduced version...
 598     } else {
 599       delete M;
 600     }
 601   }
 602
 603   BD.EmitProgressBitcode("reduced-simplified");
 604
 605   return false;
 606 }
 607
 608 static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
 609   return BD.runPasses(M);
 610 }
 611
 612 /// debugOptimizerCrash - This method is called when some pass crashes on input.
 613 /// It attempts to prune down the testcase to something reasonable, and figure
 614 /// out exactly which pass is crashing.
 615 ///
 616 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
 617   std::cout << "\n*** Debugging optimizer crash!\n";
 618
 619   // Reduce the list of passes which causes the optimizer to crash...
 620   if (!BugpointIsInterrupted)
 621     ReducePassList(*this).reduceList(PassesToRun);
 622
 623   std::cout << "\n*** Found crashing pass"
 624             << (PassesToRun.size() == 1 ? ": " : "es: ")
 625             << getPassesString(PassesToRun) << '\n';
 626
 627   EmitProgressBitcode(ID);
 628
 629   return DebugACrash(*this, TestForOptimizerCrash);
 630 }
 631
 632 static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
 633   try {
 634     BD.compileProgram(M);
 635     errs() << '\n';
 636     return false;
 637   } catch (ToolExecutionError &) {
 638     errs() << "<crash>\n";
 639     return true;  // Tool is still crashing.
 640   }
 641 }
 642
 643 /// debugCodeGeneratorCrash - This method is called when the code generator
 644 /// crashes on an input.  It attempts to reduce the input as much as possible
 645 /// while still causing the code generator to crash.
 646 bool BugDriver::debugCodeGeneratorCrash() {
 647   errs() << "*** Debugging code generator crash!\n";
 648
 649   return DebugACrash(*this, TestForCodeGenCrash);
 650 }