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<std::string> {
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<std::string> &Removed,
56 std::vector<std::string> &Kept,
61 ReducePassList::TestResult
62 ReducePassList::doTest(std::vector<std::string> &Prefix,
63 std::vector<std::string> &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(BD.getProgram(), 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(BD.getProgram(), 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)(const BugDriver &, Module *);
111 ReduceCrashingGlobalVariables(BugDriver &bd,
112 bool (*testFn)(const 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 ValueToValueMapTy VMap;
134 Module *M = CloneModule(BD.getProgram(), VMap);
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>(VMap[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)(const BugDriver &, Module *);
181 ReduceCrashingFunctions(BugDriver &bd,
182 bool (*testFn)(const 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 ValueToValueMapTy VMap;
208 Module *M = CloneModule(BD.getProgram(), VMap);
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>(VMap[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)(const BugDriver &, Module *);
254 ReduceCrashingBlocks(BugDriver &bd,
255 bool (*testFn)(const BugDriver &, Module *))
256 : BD(bd), TestFn(testFn) {}
258 virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
259 std::vector<const BasicBlock*> &Kept,
260 std::string &Error) {
261 if (!Kept.empty() && TestBlocks(Kept))
263 if (!Prefix.empty() && TestBlocks(Prefix))
268 bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
272 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
273 // Clone the program to try hacking it apart...
274 ValueToValueMapTy VMap;
275 Module *M = CloneModule(BD.getProgram(), VMap);
277 // Convert list to set for fast lookup...
278 SmallPtrSet<BasicBlock*, 8> Blocks;
279 for (unsigned i = 0, e = BBs.size(); i != e; ++i)
280 Blocks.insert(cast<BasicBlock>(VMap[BBs[i]]));
282 outs() << "Checking for crash with only these blocks:";
283 unsigned NumPrint = Blocks.size();
284 if (NumPrint > 10) NumPrint = 10;
285 for (unsigned i = 0, e = NumPrint; i != e; ++i)
286 outs() << " " << BBs[i]->getName();
287 if (NumPrint < Blocks.size())
288 outs() << "... <" << Blocks.size() << " total>";
291 // Loop over and delete any hack up any blocks that are not listed...
292 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
293 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
294 if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
295 // Loop over all of the successors of this block, deleting any PHI nodes
296 // that might include it.
297 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
298 (*SI)->removePredecessor(BB);
300 TerminatorInst *BBTerm = BB->getTerminator();
302 if (!BB->getTerminator()->getType()->isVoidTy())
303 BBTerm->replaceAllUsesWith(Constant::getNullValue(BBTerm->getType()));
305 // Replace the old terminator instruction.
306 BB->getInstList().pop_back();
307 new UnreachableInst(BB->getContext(), BB);
310 // The CFG Simplifier pass may delete one of the basic blocks we are
311 // interested in. If it does we need to take the block out of the list. Make
312 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
313 // This won't work well if blocks are unnamed, but that is just the risk we
315 std::vector<std::pair<std::string, std::string> > BlockInfo;
317 for (SmallPtrSet<BasicBlock*, 8>::iterator I = Blocks.begin(),
318 E = Blocks.end(); I != E; ++I)
319 BlockInfo.push_back(std::make_pair((*I)->getParent()->getName(),
322 // Now run the CFG simplify pass on the function...
323 std::vector<std::string> Passes;
324 Passes.push_back("simplifycfg");
325 Passes.push_back("verify");
326 Module *New = BD.runPassesOn(M, Passes);
329 errs() << "simplifycfg failed!\n";
334 // Try running on the hacked up program...
336 BD.setNewProgram(M); // It crashed, keep the trimmed version...
338 // Make sure to use basic block pointers that point into the now-current
339 // module, and that they don't include any deleted blocks.
341 const ValueSymbolTable &GST = M->getValueSymbolTable();
342 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
343 Function *F = cast<Function>(GST.lookup(BlockInfo[i].first));
344 ValueSymbolTable &ST = F->getValueSymbolTable();
345 Value* V = ST.lookup(BlockInfo[i].second);
346 if (V && V->getType() == Type::getLabelTy(V->getContext()))
347 BBs.push_back(cast<BasicBlock>(V));
351 delete M; // It didn't crash, try something else.
356 /// ReduceCrashingInstructions reducer - This works by removing the specified
357 /// non-terminator instructions and replacing them with undef.
359 class ReduceCrashingInstructions : public ListReducer<const Instruction*> {
361 bool (*TestFn)(const BugDriver &, Module *);
363 ReduceCrashingInstructions(BugDriver &bd,
364 bool (*testFn)(const BugDriver &, Module *))
365 : BD(bd), TestFn(testFn) {}
367 virtual TestResult doTest(std::vector<const Instruction*> &Prefix,
368 std::vector<const Instruction*> &Kept,
369 std::string &Error) {
370 if (!Kept.empty() && TestInsts(Kept))
372 if (!Prefix.empty() && TestInsts(Prefix))
377 bool TestInsts(std::vector<const Instruction*> &Prefix);
381 bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
383 // Clone the program to try hacking it apart...
384 ValueToValueMapTy VMap;
385 Module *M = CloneModule(BD.getProgram(), VMap);
387 // Convert list to set for fast lookup...
388 SmallPtrSet<Instruction*, 64> Instructions;
389 for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
390 assert(!isa<TerminatorInst>(Insts[i]));
391 Instructions.insert(cast<Instruction>(VMap[Insts[i]]));
394 outs() << "Checking for crash with only " << Instructions.size();
395 if (Instructions.size() == 1)
396 outs() << " instruction: ";
398 outs() << " instructions: ";
400 for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
401 for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
402 for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
403 Instruction *Inst = I++;
404 if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst) &&
405 !isa<LandingPadInst>(Inst)) {
406 if (!Inst->getType()->isVoidTy())
407 Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
408 Inst->eraseFromParent();
412 // Verify that this is still valid.
414 Passes.add(createVerifierPass());
417 // Try running on the hacked up program...
419 BD.setNewProgram(M); // It crashed, keep the trimmed version...
421 // Make sure to use instruction pointers that point into the now-current
422 // module, and that they don't include any deleted blocks.
424 for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
425 E = Instructions.end(); I != E; ++I)
429 delete M; // It didn't crash, try something else.
433 /// DebugACrash - Given a predicate that determines whether a component crashes
434 /// on a program, try to destructively reduce the program while still keeping
435 /// the predicate true.
436 static bool DebugACrash(BugDriver &BD,
437 bool (*TestFn)(const BugDriver &, Module *),
438 std::string &Error) {
439 // See if we can get away with nuking some of the global variable initializers
442 BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
443 // Now try to reduce the number of global variable initializers in the
444 // module to something small.
445 Module *M = CloneModule(BD.getProgram());
446 bool DeletedInit = false;
448 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
450 if (I->hasInitializer()) {
451 I->setInitializer(0);
452 I->setLinkage(GlobalValue::ExternalLinkage);
457 delete M; // No change made...
459 // See if the program still causes a crash...
460 outs() << "\nChecking to see if we can delete global inits: ";
462 if (TestFn(BD, M)) { // Still crashes?
464 outs() << "\n*** Able to remove all global initializers!\n";
465 } else { // No longer crashes?
466 outs() << " - Removing all global inits hides problem!\n";
469 std::vector<GlobalVariable*> GVs;
471 for (Module::global_iterator I = BD.getProgram()->global_begin(),
472 E = BD.getProgram()->global_end(); I != E; ++I)
473 if (I->hasInitializer())
476 if (GVs.size() > 1 && !BugpointIsInterrupted) {
477 outs() << "\n*** Attempting to reduce the number of global "
478 << "variables in the testcase\n";
480 unsigned OldSize = GVs.size();
481 ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs, Error);
485 if (GVs.size() < OldSize)
486 BD.EmitProgressBitcode(BD.getProgram(), "reduced-global-variables");
492 // Now try to reduce the number of functions in the module to something small.
493 std::vector<Function*> Functions;
494 for (Module::iterator I = BD.getProgram()->begin(),
495 E = BD.getProgram()->end(); I != E; ++I)
496 if (!I->isDeclaration())
497 Functions.push_back(I);
499 if (Functions.size() > 1 && !BugpointIsInterrupted) {
500 outs() << "\n*** Attempting to reduce the number of functions "
503 unsigned OldSize = Functions.size();
504 ReduceCrashingFunctions(BD, TestFn).reduceList(Functions, Error);
506 if (Functions.size() < OldSize)
507 BD.EmitProgressBitcode(BD.getProgram(), "reduced-function");
510 // Attempt to delete entire basic blocks at a time to speed up
511 // convergence... this actually works by setting the terminator of the blocks
512 // to a return instruction then running simplifycfg, which can potentially
513 // shrinks the code dramatically quickly
515 if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
516 std::vector<const BasicBlock*> Blocks;
517 for (Module::const_iterator I = BD.getProgram()->begin(),
518 E = BD.getProgram()->end(); I != E; ++I)
519 for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
520 Blocks.push_back(FI);
521 unsigned OldSize = Blocks.size();
522 ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks, Error);
523 if (Blocks.size() < OldSize)
524 BD.EmitProgressBitcode(BD.getProgram(), "reduced-blocks");
527 // Attempt to delete instructions using bisection. This should help out nasty
528 // cases with large basic blocks where the problem is at one end.
529 if (!BugpointIsInterrupted) {
530 std::vector<const Instruction*> Insts;
531 for (Module::const_iterator MI = BD.getProgram()->begin(),
532 ME = BD.getProgram()->end(); MI != ME; ++MI)
533 for (Function::const_iterator FI = MI->begin(), FE = MI->end(); FI != FE;
535 for (BasicBlock::const_iterator I = FI->begin(), E = FI->end();
537 if (!isa<TerminatorInst>(I))
540 ReduceCrashingInstructions(BD, TestFn).reduceList(Insts, Error);
543 // FIXME: This should use the list reducer to converge faster by deleting
544 // larger chunks of instructions at a time!
545 unsigned Simplification = 2;
547 if (BugpointIsInterrupted) break;
549 outs() << "\n*** Attempting to reduce testcase by deleting instruc"
550 << "tions: Simplification Level #" << Simplification << '\n';
552 // Now that we have deleted the functions that are unnecessary for the
553 // program, try to remove instructions that are not necessary to cause the
554 // crash. To do this, we loop through all of the instructions in the
555 // remaining functions, deleting them (replacing any values produced with
556 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
557 // still triggers failure, keep deleting until we cannot trigger failure
560 unsigned InstructionsToSkipBeforeDeleting = 0;
563 // Loop over all of the (non-terminator) instructions remaining in the
564 // function, attempting to delete them.
565 unsigned CurInstructionNum = 0;
566 for (Module::const_iterator FI = BD.getProgram()->begin(),
567 E = BD.getProgram()->end(); FI != E; ++FI)
568 if (!FI->isDeclaration())
569 for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
571 for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
572 I != E; ++I, ++CurInstructionNum) {
573 if (InstructionsToSkipBeforeDeleting) {
574 --InstructionsToSkipBeforeDeleting;
576 if (BugpointIsInterrupted) goto ExitLoops;
578 if (isa<LandingPadInst>(I))
581 outs() << "Checking instruction: " << *I;
582 Module *M = BD.deleteInstructionFromProgram(I, Simplification);
584 // Find out if the pass still crashes on this pass...
586 // Yup, it does, we delete the old module, and continue trying
587 // to reduce the testcase...
589 InstructionsToSkipBeforeDeleting = CurInstructionNum;
590 goto TryAgain; // I wish I had a multi-level break here!
593 // This pass didn't crash without this instruction, try the next
599 if (InstructionsToSkipBeforeDeleting) {
600 InstructionsToSkipBeforeDeleting = 0;
604 } while (Simplification);
607 // Try to clean up the testcase by running funcresolve and globaldce...
608 if (!BugpointIsInterrupted) {
609 outs() << "\n*** Attempting to perform final cleanups: ";
610 Module *M = CloneModule(BD.getProgram());
611 M = BD.performFinalCleanups(M, true);
613 // Find out if the pass still crashes on the cleaned up program...
615 BD.setNewProgram(M); // Yup, it does, keep the reduced version...
621 BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplified");
626 static bool TestForOptimizerCrash(const BugDriver &BD, Module *M) {
627 return BD.runPasses(M);
630 /// debugOptimizerCrash - This method is called when some pass crashes on input.
631 /// It attempts to prune down the testcase to something reasonable, and figure
632 /// out exactly which pass is crashing.
634 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
635 outs() << "\n*** Debugging optimizer crash!\n";
638 // Reduce the list of passes which causes the optimizer to crash...
639 if (!BugpointIsInterrupted)
640 ReducePassList(*this).reduceList(PassesToRun, Error);
641 assert(Error.empty());
643 outs() << "\n*** Found crashing pass"
644 << (PassesToRun.size() == 1 ? ": " : "es: ")
645 << getPassesString(PassesToRun) << '\n';
647 EmitProgressBitcode(Program, ID);
649 bool Success = DebugACrash(*this, TestForOptimizerCrash, Error);
650 assert(Error.empty());
654 static bool TestForCodeGenCrash(const BugDriver &BD, Module *M) {
656 BD.compileProgram(M, &Error);
657 if (!Error.empty()) {
658 errs() << "<crash>\n";
659 return true; // Tool is still crashing.
665 /// debugCodeGeneratorCrash - This method is called when the code generator
666 /// crashes on an input. It attempts to reduce the input as much as possible
667 /// while still causing the code generator to crash.
668 bool BugDriver::debugCodeGeneratorCrash(std::string &Error) {
669 errs() << "*** Debugging code generator crash!\n";
671 return DebugACrash(*this, TestForCodeGenCrash, Error);