tools/bugpoint/CrashDebugger.cpp - fp2-dev/platform/external/llvm - Gitiles

 //===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
 //
 // This file defines the bugpoint internals that narrow down compilation crashes
 //
 //===----------------------------------------------------------------------===//

 #include "BugDriver.h"
 #include "SystemUtils.h"
 #include "ListReducer.h"
 #include "llvm/Module.h"
 #include "llvm/PassManager.h"
 #include "llvm/Pass.h"
 #include "llvm/Constant.h"
 #include "llvm/iTerminators.h"
 #include "llvm/Type.h"
 #include "llvm/SymbolTable.h"
 #include "llvm/Support/CFG.h"
 #include "llvm/Analysis/Verifier.h"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Bytecode/Writer.h"
 #include <fstream>
 #include <set>

 class DebugCrashes : public ListReducer<const PassInfo*> {
   BugDriver &BD;
 public:
   DebugCrashes(BugDriver &bd) : BD(bd) {}

   // doTest - Return true iff running the "removed" passes succeeds, and running
   // the "Kept" passes fail when run on the output of the "removed" passes.  If
   // we return true, we update the current module of bugpoint.
   //
   virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
                             std::vector<const PassInfo*> &Kept);
 };

 DebugCrashes::TestResult
 DebugCrashes::doTest(std::vector<const PassInfo*> &Prefix,
                      std::vector<const PassInfo*> &Suffix) {
   std::string PrefixOutput;
   Module *OrigProgram = 0;
   if (!Prefix.empty()) {
     std::cout << "Checking to see if these passes crash: "
               << getPassesString(Prefix) << ": ";
     if (BD.runPasses(Prefix, PrefixOutput))
       return KeepPrefix;

     OrigProgram = BD.Program;

     BD.Program = BD.ParseInputFile(PrefixOutput);
     if (BD.Program == 0) {
       std::cerr << BD.getToolName() << ": Error reading bytecode file '"
                 << PrefixOutput << "'!\n";
       exit(1);
     }
     removeFile(PrefixOutput);
   }

   std::cout << "Checking to see if these passes crash: "
             << getPassesString(Suffix) << ": ";

   if (BD.runPasses(Suffix)) {
     delete OrigProgram;            // The suffix crashes alone...
     return KeepSuffix;
   }

   // Nothing failed, restore state...
   if (OrigProgram) {
     delete BD.Program;
     BD.Program = OrigProgram;
   }
   return NoFailure;
 }

 class ReduceCrashingFunctions : public ListReducer<Function*> {
   BugDriver &BD;
 public:
   ReduceCrashingFunctions(BugDriver &bd) : BD(bd) {}

   virtual TestResult doTest(std::vector<Function*> &Prefix,
                             std::vector<Function*> &Kept) {
     if (!Kept.empty() && TestFuncs(Kept))
       return KeepSuffix;
     if (!Prefix.empty() && TestFuncs(Prefix))
       return KeepPrefix;
     return NoFailure;
   }

   bool TestFuncs(std::vector<Function*> &Prefix);
 };

 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
   // Clone the program to try hacking it appart...
   Module *M = CloneModule(BD.Program);

   // Convert list to set for fast lookup...
   std::set<Function*> Functions;
   for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
     Function *CMF = M->getFunction(Funcs[i]->getName(),
                                    Funcs[i]->getFunctionType());
     assert(CMF && "Function not in module?!");
     Functions.insert(CMF);
   }

   std::cout << "Checking for crash with only these functions:";
   for (unsigned i = 0, e = Funcs.size(); i != e; ++i)
     std::cout << " " << Funcs[i]->getName();
   std::cout << ": ";

   // Loop over and delete any functions which we aren't supposed to be playing
   // with...
   for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
     if (!I->isExternal() && !Functions.count(I))
       DeleteFunctionBody(I);

   // Try running the hacked up program...
   std::swap(BD.Program, M);
   if (BD.runPasses(BD.PassesToRun)) {
     delete M;         // It crashed, keep the trimmed version...

     // Make sure to use function pointers that point into the now-current
     // module.
     Funcs.assign(Functions.begin(), Functions.end());
     return true;
   }
   delete BD.Program;  // It didn't crash, revert...
   BD.Program = M;
   return false;
 }


 /// ReduceCrashingBlocks reducer - This works by setting the terminators of all
 /// terminators except the specified basic blocks to a 'ret' instruction, then
 /// running the simplify-cfg pass.  This has the effect of chopping up the CFG
 /// really fast which can reduce large functions quickly.
 ///
 class ReduceCrashingBlocks : public ListReducer<BasicBlock*> {
   BugDriver &BD;
 public:
   ReduceCrashingBlocks(BugDriver &bd) : BD(bd) {}

   virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
                             std::vector<BasicBlock*> &Kept) {
     if (!Kept.empty() && TestBlocks(Kept))
       return KeepSuffix;
     if (!Prefix.empty() && TestBlocks(Prefix))
       return KeepPrefix;
     return NoFailure;
   }

   bool TestBlocks(std::vector<BasicBlock*> &Prefix);
 };

 bool ReduceCrashingBlocks::TestBlocks(std::vector<BasicBlock*> &BBs) {
   // Clone the program to try hacking it appart...
   Module *M = CloneModule(BD.Program);

   // Convert list to set for fast lookup...
   std::set<BasicBlock*> Blocks;
   for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
     // Convert the basic block from the original module to the new module...
     Function *F = BBs[i]->getParent();
     Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
     assert(CMF && "Function not in module?!");

     // Get the mapped basic block...
     Function::iterator CBI = CMF->begin();
     std::advance(CBI, std::distance(F->begin(), Function::iterator(BBs[i])));
     Blocks.insert(CBI);
   }

   std::cout << "Checking for crash with only these blocks:";
   for (unsigned i = 0, e = Blocks.size(); i != e; ++i)
     std::cout << " " << BBs[i]->getName();
   std::cout << ": ";

   // Loop over and delete any hack up any blocks that are not listed...
   for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
     for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
       if (!Blocks.count(BB) && !isa<ReturnInst>(BB->getTerminator())) {
         // Loop over all of the successors of this block, deleting any PHI nodes
         // that might include it.
         for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
           (*SI)->removePredecessor(BB);

         // Delete the old terminator instruction...
         BB->getInstList().pop_back();

         // Add a new return instruction of the appropriate type...
         const Type *RetTy = BB->getParent()->getReturnType();
         ReturnInst *RI = new ReturnInst(RetTy == Type::VoidTy ? 0 :
                                         Constant::getNullValue(RetTy));
         BB->getInstList().push_back(RI);
       }

   // The CFG Simplifier pass may delete one of the basic blocks we are
   // interested in.  If it does we need to take the block out of the list.  Make
   // a "persistent mapping" by turning basic blocks into <function, name> pairs.
   // This won't work well if blocks are unnamed, but that is just the risk we
   // have to take.
   std::vector<std::pair<Function*, std::string> > BlockInfo;

   for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
        I != E; ++I)
     BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));

   // Now run the CFG simplify pass on the function...
   PassManager Passes;
   Passes.add(createCFGSimplificationPass());
   Passes.add(createVerifierPass());
   Passes.run(*M);

   // Try running on the hacked up program...
   std::swap(BD.Program, M);
   if (BD.runPasses(BD.PassesToRun)) {
     delete M;         // It crashed, keep the trimmed version...

     // Make sure to use basic block pointers that point into the now-current
     // module, and that they don't include any deleted blocks.
     BBs.clear();
     for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
       SymbolTable &ST = BlockInfo[i].first->getSymbolTable();
       SymbolTable::iterator I = ST.find(Type::LabelTy);
       if (I != ST.end() && I->second.count(BlockInfo[i].second))
         BBs.push_back(cast<BasicBlock>(I->second[BlockInfo[i].second]));
     }
     return true;
   }
   delete BD.Program;  // It didn't crash, revert...
   BD.Program = M;
   return false;
 }

 /// debugCrash - This method is called when some pass crashes on input.  It
 /// attempts to prune down the testcase to something reasonable, and figure
 /// out exactly which pass is crashing.
 ///
 bool BugDriver::debugCrash() {
   bool AnyReduction = false;
   std::cout << "\n*** Debugging optimizer crash!\n";

   // Reduce the list of passes which causes the optimizer to crash...
   unsigned OldSize = PassesToRun.size();
   DebugCrashes(*this).reduceList(PassesToRun);

   std::cout << "\n*** Found crashing pass"
             << (PassesToRun.size() == 1 ? ": " : "es: ")
             << getPassesString(PassesToRun) << "\n";

   EmitProgressBytecode("passinput");

   // See if we can get away with nuking all of the global variable initializers
   // in the program...
   if (Program->gbegin() != Program->gend()) {
     Module *M = CloneModule(Program);
     bool DeletedInit = false;
     for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
       if (I->hasInitializer()) {
         I->setInitializer(0);
         I->setLinkage(GlobalValue::ExternalLinkage);
         DeletedInit = true;
       }

     if (!DeletedInit) {
       delete M;  // No change made...
     } else {
       // See if the program still causes a crash...
       std::cout << "\nChecking to see if we can delete global inits: ";
       std::swap(Program, M);
       if (runPasses(PassesToRun)) {  // Still crashes?
         AnyReduction = true;
         delete M;
         std::cout << "\n*** Able to remove all global initializers!\n";
       } else {                       // No longer crashes?
         delete Program;              // Restore program.
         Program = M;
         std::cout << "  - Removing all global inits hides problem!\n";
       }
     }
   }

   // Now try to reduce the number of functions in the module to something small.
   std::vector<Function*> Functions;
   for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
     if (!I->isExternal())
       Functions.push_back(I);

   if (Functions.size() > 1) {
     std::cout << "\n*** Attempting to reduce the number of functions "
       "in the testcase\n";

     OldSize = Functions.size();
     ReduceCrashingFunctions(*this).reduceList(Functions);

     if (Functions.size() < OldSize) {
       EmitProgressBytecode("reduced-function");
       AnyReduction = true;
     }
   }

   // Attempt to delete entire basic blocks at a time to speed up
   // convergence... this actually works by setting the terminator of the blocks
   // to a return instruction then running simplifycfg, which can potentially
   // shrinks the code dramatically quickly
   //
   std::vector<BasicBlock*> Blocks;
   for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
     for (Function::iterator FI = I->begin(), E = I->end(); FI != E; ++FI)
       Blocks.push_back(FI);
   ReduceCrashingBlocks(*this).reduceList(Blocks);

   // FIXME: This should use the list reducer to converge faster by deleting
   // larger chunks of instructions at a time!
   unsigned Simplification = 4;
   do {
     --Simplification;
     std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
               << "tions: Simplification Level #" << Simplification << "\n";

     // Now that we have deleted the functions that are unneccesary for the
     // program, try to remove instructions that are not neccesary to cause the
     // crash.  To do this, we loop through all of the instructions in the
     // remaining functions, deleting them (replacing any values produced with
     // nulls), and then running ADCE and SimplifyCFG.  If the transformed input
     // still triggers failure, keep deleting until we cannot trigger failure
     // anymore.
     //
   TryAgain:

     // Loop over all of the (non-terminator) instructions remaining in the
     // function, attempting to delete them.
     for (Module::iterator FI = Program->begin(), E = Program->end();
          FI != E; ++FI)
       if (!FI->isExternal()) {
         for (Function::iterator BI = FI->begin(), E = FI->end(); BI != E; ++BI)
           for (BasicBlock::iterator I = BI->begin(), E = --BI->end();
                I != E; ++I) {
             Module *M = deleteInstructionFromProgram(I, Simplification);

             // Make the function the current program...
             std::swap(Program, M);

             // Find out if the pass still crashes on this pass...
             std::cout << "Checking instruction '" << I->getName() << "': ";
             if (runPasses(PassesToRun)) {
               // Yup, it does, we delete the old module, and continue trying to
               // reduce the testcase...
               delete M;
               AnyReduction = true;
               goto TryAgain;  // I wish I had a multi-level break here!
             }

             // This pass didn't crash without this instruction, try the next
             // one.
             delete Program;
             Program = M;
           }
       }
   } while (Simplification);

   // Try to clean up the testcase by running funcresolve and globaldce...
   std::cout << "\n*** Attempting to perform final cleanups: ";
   Module *M = performFinalCleanups();
   std::swap(Program, M);

   // Find out if the pass still crashes on the cleaned up program...
   if (runPasses(PassesToRun)) {
     // Yup, it does, keep the reduced version...
     delete M;
     AnyReduction = true;
   } else {
     delete Program;   // Otherwise, restore the original module...
     Program = M;
   }

   if (AnyReduction)
     EmitProgressBytecode("reduced-simplified");

   return false;
 }
	//===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
	//
	// This file defines the bugpoint internals that narrow down compilation crashes
	//
	//===----------------------------------------------------------------------===//

	#include "BugDriver.h"
	#include "SystemUtils.h"
	#include "ListReducer.h"
	#include "llvm/Module.h"
	#include "llvm/PassManager.h"
	#include "llvm/Pass.h"
	#include "llvm/Constant.h"
	#include "llvm/iTerminators.h"
	#include "llvm/Type.h"
	#include "llvm/SymbolTable.h"
	#include "llvm/Support/CFG.h"
	#include "llvm/Analysis/Verifier.h"
	#include "llvm/Transforms/Scalar.h"
	#include "llvm/Transforms/Utils/Cloning.h"
	#include "llvm/Bytecode/Writer.h"
	#include <fstream>
	#include <set>

	class DebugCrashes : public ListReducer<const PassInfo*> {
	BugDriver &BD;
	public:
	DebugCrashes(BugDriver &bd) : BD(bd) {}

	// doTest - Return true iff running the "removed" passes succeeds, and running
	// the "Kept" passes fail when run on the output of the "removed" passes. If
	// we return true, we update the current module of bugpoint.
	//
	virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
	std::vector<const PassInfo*> &Kept);
	};

	DebugCrashes::TestResult
	DebugCrashes::doTest(std::vector<const PassInfo*> &Prefix,
	std::vector<const PassInfo*> &Suffix) {
	std::string PrefixOutput;
	Module *OrigProgram = 0;
	if (!Prefix.empty()) {
	std::cout << "Checking to see if these passes crash: "
	<< getPassesString(Prefix) << ": ";
	if (BD.runPasses(Prefix, PrefixOutput))
	return KeepPrefix;

	OrigProgram = BD.Program;

	BD.Program = BD.ParseInputFile(PrefixOutput);
	if (BD.Program == 0) {
	std::cerr << BD.getToolName() << ": Error reading bytecode file '"
	<< PrefixOutput << "'!\n";
	exit(1);
	}
	removeFile(PrefixOutput);
	}

	std::cout << "Checking to see if these passes crash: "
	<< getPassesString(Suffix) << ": ";

	if (BD.runPasses(Suffix)) {
	delete OrigProgram; // The suffix crashes alone...
	return KeepSuffix;
	}

	// Nothing failed, restore state...
	if (OrigProgram) {
	delete BD.Program;
	BD.Program = OrigProgram;
	}
	return NoFailure;
	}

	class ReduceCrashingFunctions : public ListReducer<Function*> {
	BugDriver &BD;
	public:
	ReduceCrashingFunctions(BugDriver &bd) : BD(bd) {}

	virtual TestResult doTest(std::vector<Function*> &Prefix,
	std::vector<Function*> &Kept) {
	if (!Kept.empty() && TestFuncs(Kept))
	return KeepSuffix;
	if (!Prefix.empty() && TestFuncs(Prefix))
	return KeepPrefix;
	return NoFailure;
	}

	bool TestFuncs(std::vector<Function*> &Prefix);
	};

	bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
	// Clone the program to try hacking it appart...
	Module *M = CloneModule(BD.Program);

	// Convert list to set for fast lookup...
	std::set<Function*> Functions;
	for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
	Function *CMF = M->getFunction(Funcs[i]->getName(),
	Funcs[i]->getFunctionType());
	assert(CMF && "Function not in module?!");
	Functions.insert(CMF);
	}

	std::cout << "Checking for crash with only these functions:";
	for (unsigned i = 0, e = Funcs.size(); i != e; ++i)
	std::cout << " " << Funcs[i]->getName();
	std::cout << ": ";

	// Loop over and delete any functions which we aren't supposed to be playing
	// with...
	for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
	if (!I->isExternal() && !Functions.count(I))
	DeleteFunctionBody(I);

	// Try running the hacked up program...
	std::swap(BD.Program, M);
	if (BD.runPasses(BD.PassesToRun)) {
	delete M; // It crashed, keep the trimmed version...

	// Make sure to use function pointers that point into the now-current
	// module.
	Funcs.assign(Functions.begin(), Functions.end());
	return true;
	}
	delete BD.Program; // It didn't crash, revert...
	BD.Program = M;
	return false;
	}


	/// ReduceCrashingBlocks reducer - This works by setting the terminators of all
	/// terminators except the specified basic blocks to a 'ret' instruction, then
	/// running the simplify-cfg pass. This has the effect of chopping up the CFG
	/// really fast which can reduce large functions quickly.
	///
	class ReduceCrashingBlocks : public ListReducer<BasicBlock*> {
	BugDriver &BD;
	public:
	ReduceCrashingBlocks(BugDriver &bd) : BD(bd) {}

	virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
	std::vector<BasicBlock*> &Kept) {
	if (!Kept.empty() && TestBlocks(Kept))
	return KeepSuffix;
	if (!Prefix.empty() && TestBlocks(Prefix))
	return KeepPrefix;
	return NoFailure;
	}

	bool TestBlocks(std::vector<BasicBlock*> &Prefix);
	};

	bool ReduceCrashingBlocks::TestBlocks(std::vector<BasicBlock*> &BBs) {
	// Clone the program to try hacking it appart...
	Module *M = CloneModule(BD.Program);

	// Convert list to set for fast lookup...
	std::set<BasicBlock*> Blocks;
	for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
	// Convert the basic block from the original module to the new module...
	Function *F = BBs[i]->getParent();
	Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
	assert(CMF && "Function not in module?!");

	// Get the mapped basic block...
	Function::iterator CBI = CMF->begin();
	std::advance(CBI, std::distance(F->begin(), Function::iterator(BBs[i])));
	Blocks.insert(CBI);
	}

	std::cout << "Checking for crash with only these blocks:";
	for (unsigned i = 0, e = Blocks.size(); i != e; ++i)
	std::cout << " " << BBs[i]->getName();
	std::cout << ": ";

	// Loop over and delete any hack up any blocks that are not listed...
	for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
	for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
	if (!Blocks.count(BB) && !isa<ReturnInst>(BB->getTerminator())) {
	// Loop over all of the successors of this block, deleting any PHI nodes
	// that might include it.
	for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
	(*SI)->removePredecessor(BB);

	// Delete the old terminator instruction...
	BB->getInstList().pop_back();

	// Add a new return instruction of the appropriate type...
	const Type *RetTy = BB->getParent()->getReturnType();
	ReturnInst *RI = new ReturnInst(RetTy == Type::VoidTy ? 0 :
	Constant::getNullValue(RetTy));
	BB->getInstList().push_back(RI);
	}

	// The CFG Simplifier pass may delete one of the basic blocks we are
	// interested in. If it does we need to take the block out of the list. Make
	// a "persistent mapping" by turning basic blocks into <function, name> pairs.
	// This won't work well if blocks are unnamed, but that is just the risk we
	// have to take.
	std::vector<std::pair<Function*, std::string> > BlockInfo;

	for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
	I != E; ++I)
	BlockInfo.push_back(std::make_pair((I)->getParent(), (I)->getName()));

	// Now run the CFG simplify pass on the function...
	PassManager Passes;
	Passes.add(createCFGSimplificationPass());
	Passes.add(createVerifierPass());
	Passes.run(*M);

	// Try running on the hacked up program...
	std::swap(BD.Program, M);
	if (BD.runPasses(BD.PassesToRun)) {
	delete M; // It crashed, keep the trimmed version...

	// Make sure to use basic block pointers that point into the now-current
	// module, and that they don't include any deleted blocks.
	BBs.clear();
	for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
	SymbolTable &ST = BlockInfo[i].first->getSymbolTable();
	SymbolTable::iterator I = ST.find(Type::LabelTy);
	if (I != ST.end() && I->second.count(BlockInfo[i].second))
	BBs.push_back(cast<BasicBlock>(I->second[BlockInfo[i].second]));
	}
	return true;
	}
	delete BD.Program; // It didn't crash, revert...
	BD.Program = M;
	return false;
	}

	/// debugCrash - This method is called when some pass crashes on input. It
	/// attempts to prune down the testcase to something reasonable, and figure
	/// out exactly which pass is crashing.
	///
	bool BugDriver::debugCrash() {
	bool AnyReduction = false;
	std::cout << "\n*** Debugging optimizer crash!\n";

	// Reduce the list of passes which causes the optimizer to crash...
	unsigned OldSize = PassesToRun.size();
	DebugCrashes(*this).reduceList(PassesToRun);

	std::cout << "\n*** Found crashing pass"
	<< (PassesToRun.size() == 1 ? ": " : "es: ")
	<< getPassesString(PassesToRun) << "\n";

	EmitProgressBytecode("passinput");

	// See if we can get away with nuking all of the global variable initializers
	// in the program...
	if (Program->gbegin() != Program->gend()) {
	Module *M = CloneModule(Program);
	bool DeletedInit = false;
	for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
	if (I->hasInitializer()) {
	I->setInitializer(0);
	I->setLinkage(GlobalValue::ExternalLinkage);
	DeletedInit = true;
	}

	if (!DeletedInit) {
	delete M; // No change made...
	} else {
	// See if the program still causes a crash...
	std::cout << "\nChecking to see if we can delete global inits: ";
	std::swap(Program, M);
	if (runPasses(PassesToRun)) { // Still crashes?
	AnyReduction = true;
	delete M;
	std::cout << "\n*** Able to remove all global initializers!\n";
	} else { // No longer crashes?
	delete Program; // Restore program.
	Program = M;
	std::cout << " - Removing all global inits hides problem!\n";
	}
	}
	}

	// Now try to reduce the number of functions in the module to something small.
	std::vector<Function*> Functions;
	for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
	if (!I->isExternal())
	Functions.push_back(I);

	if (Functions.size() > 1) {
	std::cout << "\n*** Attempting to reduce the number of functions "
	"in the testcase\n";

	OldSize = Functions.size();
	ReduceCrashingFunctions(*this).reduceList(Functions);

	if (Functions.size() < OldSize) {
	EmitProgressBytecode("reduced-function");
	AnyReduction = true;
	}
	}

	// Attempt to delete entire basic blocks at a time to speed up
	// convergence... this actually works by setting the terminator of the blocks
	// to a return instruction then running simplifycfg, which can potentially
	// shrinks the code dramatically quickly
	//
	std::vector<BasicBlock*> Blocks;
	for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
	for (Function::iterator FI = I->begin(), E = I->end(); FI != E; ++FI)
	Blocks.push_back(FI);
	ReduceCrashingBlocks(*this).reduceList(Blocks);

	// FIXME: This should use the list reducer to converge faster by deleting
	// larger chunks of instructions at a time!
	unsigned Simplification = 4;
	do {
	--Simplification;
	std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
	<< "tions: Simplification Level #" << Simplification << "\n";

	// Now that we have deleted the functions that are unneccesary for the
	// program, try to remove instructions that are not neccesary to cause the
	// crash. To do this, we loop through all of the instructions in the
	// remaining functions, deleting them (replacing any values produced with
	// nulls), and then running ADCE and SimplifyCFG. If the transformed input
	// still triggers failure, keep deleting until we cannot trigger failure
	// anymore.
	//
	TryAgain:

	// Loop over all of the (non-terminator) instructions remaining in the
	// function, attempting to delete them.
	for (Module::iterator FI = Program->begin(), E = Program->end();
	FI != E; ++FI)
	if (!FI->isExternal()) {
	for (Function::iterator BI = FI->begin(), E = FI->end(); BI != E; ++BI)
	for (BasicBlock::iterator I = BI->begin(), E = --BI->end();
	I != E; ++I) {
	Module *M = deleteInstructionFromProgram(I, Simplification);

	// Make the function the current program...
	std::swap(Program, M);

	// Find out if the pass still crashes on this pass...
	std::cout << "Checking instruction '" << I->getName() << "': ";
	if (runPasses(PassesToRun)) {
	// Yup, it does, we delete the old module, and continue trying to
	// reduce the testcase...
	delete M;
	AnyReduction = true;
	goto TryAgain; // I wish I had a multi-level break here!
	}

	// This pass didn't crash without this instruction, try the next
	// one.
	delete Program;
	Program = M;
	}
	}
	} while (Simplification);

	// Try to clean up the testcase by running funcresolve and globaldce...
	std::cout << "\n*** Attempting to perform final cleanups: ";
	Module *M = performFinalCleanups();
	std::swap(Program, M);

	// Find out if the pass still crashes on the cleaned up program...
	if (runPasses(PassesToRun)) {
	// Yup, it does, keep the reduced version...
	delete M;
	AnyReduction = true;
	} else {
	delete Program; // Otherwise, restore the original module...
	Program = M;
	}

	if (AnyReduction)
	EmitProgressBytecode("reduced-simplified");

	return false;
	}