1 //===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the bugpoint internals that narrow down compilation crashes
12 //===----------------------------------------------------------------------===//
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"
37 cl::desc("Force function reduction to keep main"),
40 NoGlobalRM ("disable-global-remove",
41 cl::desc("Do not remove global variables"),
46 class ReducePassList : public ListReducer<const PassInfo*> {
49 ReducePassList(BugDriver &bd) : BD(bd) {}
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.
55 virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
56 std::vector<const PassInfo*> &Kept,
61 ReducePassList::TestResult
62 ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
63 std::vector<const PassInfo*> &Suffix,
65 sys::Path PrefixOutput;
66 Module *OrigProgram = 0;
67 if (!Prefix.empty()) {
68 outs() << "Checking to see if these passes crash: "
69 << getPassesString(Prefix) << ": ";
70 std::string PfxOutput;
71 if (BD.runPasses(Prefix, PfxOutput))
74 PrefixOutput.set(PfxOutput);
75 OrigProgram = BD.Program;
77 BD.Program = ParseInputFile(PrefixOutput.str(), BD.getContext());
78 if (BD.Program == 0) {
79 errs() << BD.getToolName() << ": Error reading bitcode file '"
80 << PrefixOutput.str() << "'!\n";
83 PrefixOutput.eraseFromDisk();
86 outs() << "Checking to see if these passes crash: "
87 << getPassesString(Suffix) << ": ";
89 if (BD.runPasses(Suffix)) {
90 delete OrigProgram; // The suffix crashes alone...
94 // Nothing failed, restore state...
97 BD.Program = OrigProgram;
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.
107 class ReduceCrashingGlobalVariables : public ListReducer<GlobalVariable*> {
109 bool (*TestFn)(BugDriver &, Module *);
111 ReduceCrashingGlobalVariables(BugDriver &bd,
112 bool (*testFn)(BugDriver &, Module *))
113 : BD(bd), TestFn(testFn) {}
115 virtual TestResult doTest(std::vector<GlobalVariable*> &Prefix,
116 std::vector<GlobalVariable*> &Kept,
117 std::string &Error) {
118 if (!Kept.empty() && TestGlobalVariables(Kept))
120 if (!Prefix.empty() && TestGlobalVariables(Prefix))
125 bool TestGlobalVariables(std::vector<GlobalVariable*> &GVs);
130 ReduceCrashingGlobalVariables::TestGlobalVariables(
131 std::vector<GlobalVariable*> &GVs) {
132 // Clone the program to try hacking it apart...
133 DenseMap<const Value*, Value*> ValueMap;
134 Module *M = CloneModule(BD.getProgram(), ValueMap);
136 // Convert list to set for fast lookup...
137 std::set<GlobalVariable*> GVSet;
139 for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
140 GlobalVariable* CMGV = cast<GlobalVariable>(ValueMap[GVs[i]]);
141 assert(CMGV && "Global Variable not in module?!");
145 outs() << "Checking for crash with only these global variables: ";
146 PrintGlobalVariableList(GVs);
149 // Loop over and delete any global variables which we aren't supposed to be
151 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
153 if (I->hasInitializer() && !GVSet.count(I)) {
154 I->setInitializer(0);
155 I->setLinkage(GlobalValue::ExternalLinkage);
158 // Try running the hacked up program...
160 BD.setNewProgram(M); // It crashed, keep the trimmed version...
162 // Make sure to use global variable pointers that point into the now-current
164 GVs.assign(GVSet.begin(), GVSet.end());
173 /// ReduceCrashingFunctions reducer - This works by removing functions and
174 /// seeing if the program still crashes. If it does, then keep the newer,
177 class ReduceCrashingFunctions : public ListReducer<Function*> {
179 bool (*TestFn)(BugDriver &, Module *);
181 ReduceCrashingFunctions(BugDriver &bd,
182 bool (*testFn)(BugDriver &, Module *))
183 : BD(bd), TestFn(testFn) {}
185 virtual TestResult doTest(std::vector<Function*> &Prefix,
186 std::vector<Function*> &Kept,
187 std::string &Error) {
188 if (!Kept.empty() && TestFuncs(Kept))
190 if (!Prefix.empty() && TestFuncs(Prefix))
195 bool TestFuncs(std::vector<Function*> &Prefix);
199 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
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())
206 // Clone the program to try hacking it apart...
207 DenseMap<const Value*, Value*> ValueMap;
208 Module *M = CloneModule(BD.getProgram(), ValueMap);
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);
220 outs() << "Checking for crash with only these functions: ";
221 PrintFunctionList(Funcs);
224 // Loop over and delete any functions which we aren't supposed to be playing
226 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
227 if (!I->isDeclaration() && !Functions.count(I))
228 DeleteFunctionBody(I);
230 // Try running the hacked up program...
232 BD.setNewProgram(M); // It crashed, keep the trimmed version...
234 // Make sure to use function pointers that point into the now-current
236 Funcs.assign(Functions.begin(), Functions.end());
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.
250 class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
252 bool (*TestFn)(BugDriver &, Module *);
254 ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
255 : BD(bd), TestFn(testFn) {}
257 virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
258 std::vector<const BasicBlock*> &Kept,
259 std::string &Error) {
260 if (!Kept.empty() && TestBlocks(Kept))
262 if (!Prefix.empty() && TestBlocks(Prefix))
267 bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
271 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
272 // Clone the program to try hacking it apart...
273 DenseMap<const Value*, Value*> ValueMap;
274 Module *M = CloneModule(BD.getProgram(), ValueMap);
276 // Convert list to set for fast lookup...
277 SmallPtrSet<BasicBlock*, 8> Blocks;
278 for (unsigned i = 0, e = BBs.size(); i != e; ++i)
279 Blocks.insert(cast<BasicBlock>(ValueMap[BBs[i]]));
281 outs() << "Checking for crash with only these blocks:";
282 unsigned NumPrint = Blocks.size();
283 if (NumPrint > 10) NumPrint = 10;
284 for (unsigned i = 0, e = NumPrint; i != e; ++i)
285 outs() << " " << BBs[i]->getName();
286 if (NumPrint < Blocks.size())
287 outs() << "... <" << Blocks.size() << " total>";
290 // Loop over and delete any hack up any blocks that are not listed...
291 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
292 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
293 if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
294 // Loop over all of the successors of this block, deleting any PHI nodes
295 // that might include it.
296 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
297 (*SI)->removePredecessor(BB);
299 TerminatorInst *BBTerm = BB->getTerminator();
301 if (BBTerm->getType()->isStructTy())
302 BBTerm->replaceAllUsesWith(UndefValue::get(BBTerm->getType()));
303 else if (BB->getTerminator()->getType() !=
304 Type::getVoidTy(BB->getContext()))
305 BBTerm->replaceAllUsesWith(Constant::getNullValue(BBTerm->getType()));
307 // Replace the old terminator instruction.
308 BB->getInstList().pop_back();
309 new UnreachableInst(BB->getContext(), BB);
312 // The CFG Simplifier pass may delete one of the basic blocks we are
313 // interested in. If it does we need to take the block out of the list. Make
314 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
315 // This won't work well if blocks are unnamed, but that is just the risk we
317 std::vector<std::pair<Function*, std::string> > BlockInfo;
319 for (SmallPtrSet<BasicBlock*, 8>::iterator I = Blocks.begin(),
320 E = Blocks.end(); I != E; ++I)
321 BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
323 // Now run the CFG simplify pass on the function...
325 Passes.add(createCFGSimplificationPass());
326 Passes.add(createVerifierPass());
329 // Try running on the hacked up program...
331 BD.setNewProgram(M); // It crashed, keep the trimmed version...
333 // Make sure to use basic block pointers that point into the now-current
334 // module, and that they don't include any deleted blocks.
336 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
337 ValueSymbolTable &ST = BlockInfo[i].first->getValueSymbolTable();
338 Value* V = ST.lookup(BlockInfo[i].second);
339 if (V && V->getType() == Type::getLabelTy(V->getContext()))
340 BBs.push_back(cast<BasicBlock>(V));
344 delete M; // It didn't crash, try something else.
349 /// ReduceCrashingInstructions reducer - This works by removing the specified
350 /// non-terminator instructions and replacing them with undef.
352 class ReduceCrashingInstructions : public ListReducer<const Instruction*> {
354 bool (*TestFn)(BugDriver &, Module *);
356 ReduceCrashingInstructions(BugDriver &bd, bool (*testFn)(BugDriver &,
358 : BD(bd), TestFn(testFn) {}
360 virtual TestResult doTest(std::vector<const Instruction*> &Prefix,
361 std::vector<const Instruction*> &Kept,
362 std::string &Error) {
363 if (!Kept.empty() && TestInsts(Kept))
365 if (!Prefix.empty() && TestInsts(Prefix))
370 bool TestInsts(std::vector<const Instruction*> &Prefix);
374 bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
376 // Clone the program to try hacking it apart...
377 DenseMap<const Value*, Value*> ValueMap;
378 Module *M = CloneModule(BD.getProgram(), ValueMap);
380 // Convert list to set for fast lookup...
381 SmallPtrSet<Instruction*, 64> Instructions;
382 for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
383 assert(!isa<TerminatorInst>(Insts[i]));
384 Instructions.insert(cast<Instruction>(ValueMap[Insts[i]]));
387 outs() << "Checking for crash with only " << Instructions.size();
388 if (Instructions.size() == 1)
389 outs() << " instruction: ";
391 outs() << " instructions: ";
393 for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
394 for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
395 for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
396 Instruction *Inst = I++;
397 if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst)) {
398 if (Inst->getType() != Type::getVoidTy(Inst->getContext()))
399 Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
400 Inst->eraseFromParent();
404 // Verify that this is still valid.
406 Passes.add(createVerifierPass());
409 // Try running on the hacked up program...
411 BD.setNewProgram(M); // It crashed, keep the trimmed version...
413 // Make sure to use instruction pointers that point into the now-current
414 // module, and that they don't include any deleted blocks.
416 for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
417 E = Instructions.end(); I != E; ++I)
421 delete M; // It didn't crash, try something else.
425 /// DebugACrash - Given a predicate that determines whether a component crashes
426 /// on a program, try to destructively reduce the program while still keeping
427 /// the predicate true.
428 static bool DebugACrash(BugDriver &BD, bool (*TestFn)(BugDriver &, Module *),
429 std::string &Error) {
430 // See if we can get away with nuking some of the global variable initializers
433 BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
434 // Now try to reduce the number of global variable initializers in the
435 // module to something small.
436 Module *M = CloneModule(BD.getProgram());
437 bool DeletedInit = false;
439 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
441 if (I->hasInitializer()) {
442 I->setInitializer(0);
443 I->setLinkage(GlobalValue::ExternalLinkage);
448 delete M; // No change made...
450 // See if the program still causes a crash...
451 outs() << "\nChecking to see if we can delete global inits: ";
453 if (TestFn(BD, M)) { // Still crashes?
455 outs() << "\n*** Able to remove all global initializers!\n";
456 } else { // No longer crashes?
457 outs() << " - Removing all global inits hides problem!\n";
460 std::vector<GlobalVariable*> GVs;
462 for (Module::global_iterator I = BD.getProgram()->global_begin(),
463 E = BD.getProgram()->global_end(); I != E; ++I)
464 if (I->hasInitializer())
467 if (GVs.size() > 1 && !BugpointIsInterrupted) {
468 outs() << "\n*** Attempting to reduce the number of global "
469 << "variables in the testcase\n";
471 unsigned OldSize = GVs.size();
472 ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs, Error);
476 if (GVs.size() < OldSize)
477 BD.EmitProgressBitcode("reduced-global-variables");
483 // Now try to reduce the number of functions in the module to something small.
484 std::vector<Function*> Functions;
485 for (Module::iterator I = BD.getProgram()->begin(),
486 E = BD.getProgram()->end(); I != E; ++I)
487 if (!I->isDeclaration())
488 Functions.push_back(I);
490 if (Functions.size() > 1 && !BugpointIsInterrupted) {
491 outs() << "\n*** Attempting to reduce the number of functions "
494 unsigned OldSize = Functions.size();
495 ReduceCrashingFunctions(BD, TestFn).reduceList(Functions, Error);
497 if (Functions.size() < OldSize)
498 BD.EmitProgressBitcode("reduced-function");
501 // Attempt to delete entire basic blocks at a time to speed up
502 // convergence... this actually works by setting the terminator of the blocks
503 // to a return instruction then running simplifycfg, which can potentially
504 // shrinks the code dramatically quickly
506 if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
507 std::vector<const BasicBlock*> Blocks;
508 for (Module::const_iterator I = BD.getProgram()->begin(),
509 E = BD.getProgram()->end(); I != E; ++I)
510 for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
511 Blocks.push_back(FI);
512 unsigned OldSize = Blocks.size();
513 ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks, Error);
514 if (Blocks.size() < OldSize)
515 BD.EmitProgressBitcode("reduced-blocks");
518 // Attempt to delete instructions using bisection. This should help out nasty
519 // cases with large basic blocks where the problem is at one end.
520 if (!BugpointIsInterrupted) {
521 std::vector<const Instruction*> Insts;
522 for (Module::const_iterator MI = BD.getProgram()->begin(),
523 ME = BD.getProgram()->end(); MI != ME; ++MI)
524 for (Function::const_iterator FI = MI->begin(), FE = MI->end(); FI != FE;
526 for (BasicBlock::const_iterator I = FI->begin(), E = FI->end();
528 if (!isa<TerminatorInst>(I))
531 ReduceCrashingInstructions(BD, TestFn).reduceList(Insts, Error);
534 // FIXME: This should use the list reducer to converge faster by deleting
535 // larger chunks of instructions at a time!
536 unsigned Simplification = 2;
538 if (BugpointIsInterrupted) break;
540 outs() << "\n*** Attempting to reduce testcase by deleting instruc"
541 << "tions: Simplification Level #" << Simplification << '\n';
543 // Now that we have deleted the functions that are unnecessary for the
544 // program, try to remove instructions that are not necessary to cause the
545 // crash. To do this, we loop through all of the instructions in the
546 // remaining functions, deleting them (replacing any values produced with
547 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
548 // still triggers failure, keep deleting until we cannot trigger failure
551 unsigned InstructionsToSkipBeforeDeleting = 0;
554 // Loop over all of the (non-terminator) instructions remaining in the
555 // function, attempting to delete them.
556 unsigned CurInstructionNum = 0;
557 for (Module::const_iterator FI = BD.getProgram()->begin(),
558 E = BD.getProgram()->end(); FI != E; ++FI)
559 if (!FI->isDeclaration())
560 for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
562 for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
563 I != E; ++I, ++CurInstructionNum)
564 if (InstructionsToSkipBeforeDeleting) {
565 --InstructionsToSkipBeforeDeleting;
567 if (BugpointIsInterrupted) goto ExitLoops;
569 outs() << "Checking instruction: " << *I;
570 Module *M = BD.deleteInstructionFromProgram(I, Simplification);
572 // Find out if the pass still crashes on this pass...
574 // Yup, it does, we delete the old module, and continue trying
575 // to reduce the testcase...
577 InstructionsToSkipBeforeDeleting = CurInstructionNum;
578 goto TryAgain; // I wish I had a multi-level break here!
581 // This pass didn't crash without this instruction, try the next
586 if (InstructionsToSkipBeforeDeleting) {
587 InstructionsToSkipBeforeDeleting = 0;
591 } while (Simplification);
594 // Try to clean up the testcase by running funcresolve and globaldce...
595 if (!BugpointIsInterrupted) {
596 outs() << "\n*** Attempting to perform final cleanups: ";
597 Module *M = CloneModule(BD.getProgram());
598 M = BD.performFinalCleanups(M, true);
600 // Find out if the pass still crashes on the cleaned up program...
602 BD.setNewProgram(M); // Yup, it does, keep the reduced version...
608 BD.EmitProgressBitcode("reduced-simplified");
613 static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
614 return BD.runPasses(M);
617 /// debugOptimizerCrash - This method is called when some pass crashes on input.
618 /// It attempts to prune down the testcase to something reasonable, and figure
619 /// out exactly which pass is crashing.
621 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
622 outs() << "\n*** Debugging optimizer crash!\n";
625 // Reduce the list of passes which causes the optimizer to crash...
626 if (!BugpointIsInterrupted)
627 ReducePassList(*this).reduceList(PassesToRun, Error);
628 assert(Error.empty());
630 outs() << "\n*** Found crashing pass"
631 << (PassesToRun.size() == 1 ? ": " : "es: ")
632 << getPassesString(PassesToRun) << '\n';
634 EmitProgressBitcode(ID);
636 bool Success = DebugACrash(*this, TestForOptimizerCrash, Error);
637 assert(Error.empty());
641 static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
643 BD.compileProgram(M, &Error);
644 if (!Error.empty()) {
645 errs() << "<crash>\n";
646 return true; // Tool is still crashing.
652 /// debugCodeGeneratorCrash - This method is called when the code generator
653 /// crashes on an input. It attempts to reduce the input as much as possible
654 /// while still causing the code generator to crash.
655 bool BugDriver::debugCodeGeneratorCrash(std::string &Error) {
656 errs() << "*** Debugging code generator crash!\n";
658 return DebugACrash(*this, TestForCodeGenCrash, Error);