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 "ListReducer.h"
16 #include "ToolRunner.h"
17 #include "llvm/ADT/SmallPtrSet.h"
18 #include "llvm/IR/CFG.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DerivedTypes.h"
21 #include "llvm/IR/Instructions.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/IR/ValueSymbolTable.h"
24 #include "llvm/IR/Verifier.h"
25 #include "llvm/Pass.h"
26 #include "llvm/PassManager.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/FileUtilities.h"
29 #include "llvm/Transforms/Scalar.h"
30 #include "llvm/Transforms/Utils/Cloning.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 TestResult doTest(std::vector<std::string> &Removed,
56 std::vector<std::string> &Kept,
57 std::string &Error) override;
61 ReducePassList::TestResult
62 ReducePassList::doTest(std::vector<std::string> &Prefix,
63 std::vector<std::string> &Suffix,
65 std::string PrefixOutput;
66 Module *OrigProgram = nullptr;
67 if (!Prefix.empty()) {
68 outs() << "Checking to see if these passes crash: "
69 << getPassesString(Prefix) << ": ";
70 if (BD.runPasses(BD.getProgram(), Prefix, PrefixOutput))
73 OrigProgram = BD.Program;
75 BD.Program = ParseInputFile(PrefixOutput, BD.getContext());
76 if (BD.Program == nullptr) {
77 errs() << BD.getToolName() << ": Error reading bitcode file '"
78 << PrefixOutput << "'!\n";
81 sys::fs::remove(PrefixOutput);
84 outs() << "Checking to see if these passes crash: "
85 << getPassesString(Suffix) << ": ";
87 if (BD.runPasses(BD.getProgram(), Suffix)) {
88 delete OrigProgram; // The suffix crashes alone...
92 // Nothing failed, restore state...
95 BD.Program = OrigProgram;
101 /// ReduceCrashingGlobalVariables - This works by removing the global
102 /// variable's initializer and seeing if the program still crashes. If it
103 /// does, then we keep that program and try again.
105 class ReduceCrashingGlobalVariables : public ListReducer<GlobalVariable*> {
107 bool (*TestFn)(const BugDriver &, Module *);
109 ReduceCrashingGlobalVariables(BugDriver &bd,
110 bool (*testFn)(const BugDriver &, Module *))
111 : BD(bd), TestFn(testFn) {}
113 TestResult doTest(std::vector<GlobalVariable*> &Prefix,
114 std::vector<GlobalVariable*> &Kept,
115 std::string &Error) override {
116 if (!Kept.empty() && TestGlobalVariables(Kept))
118 if (!Prefix.empty() && TestGlobalVariables(Prefix))
123 bool TestGlobalVariables(std::vector<GlobalVariable*> &GVs);
128 ReduceCrashingGlobalVariables::TestGlobalVariables(
129 std::vector<GlobalVariable*> &GVs) {
130 // Clone the program to try hacking it apart...
131 ValueToValueMapTy VMap;
132 Module *M = CloneModule(BD.getProgram(), VMap);
134 // Convert list to set for fast lookup...
135 std::set<GlobalVariable*> GVSet;
137 for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
138 GlobalVariable* CMGV = cast<GlobalVariable>(VMap[GVs[i]]);
139 assert(CMGV && "Global Variable not in module?!");
143 outs() << "Checking for crash with only these global variables: ";
144 PrintGlobalVariableList(GVs);
147 // Loop over and delete any global variables which we aren't supposed to be
149 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
151 if (I->hasInitializer() && !GVSet.count(I)) {
152 I->setInitializer(nullptr);
153 I->setLinkage(GlobalValue::ExternalLinkage);
156 // Try running the hacked up program...
158 BD.setNewProgram(M); // It crashed, keep the trimmed version...
160 // Make sure to use global variable pointers that point into the now-current
162 GVs.assign(GVSet.begin(), GVSet.end());
171 /// ReduceCrashingFunctions reducer - This works by removing functions and
172 /// seeing if the program still crashes. If it does, then keep the newer,
175 class ReduceCrashingFunctions : public ListReducer<Function*> {
177 bool (*TestFn)(const BugDriver &, Module *);
179 ReduceCrashingFunctions(BugDriver &bd,
180 bool (*testFn)(const BugDriver &, Module *))
181 : BD(bd), TestFn(testFn) {}
183 TestResult doTest(std::vector<Function*> &Prefix,
184 std::vector<Function*> &Kept,
185 std::string &Error) override {
186 if (!Kept.empty() && TestFuncs(Kept))
188 if (!Prefix.empty() && TestFuncs(Prefix))
193 bool TestFuncs(std::vector<Function*> &Prefix);
197 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
198 // If main isn't present, claim there is no problem.
199 if (KeepMain && std::find(Funcs.begin(), Funcs.end(),
200 BD.getProgram()->getFunction("main")) ==
204 // Clone the program to try hacking it apart...
205 ValueToValueMapTy VMap;
206 Module *M = CloneModule(BD.getProgram(), VMap);
208 // Convert list to set for fast lookup...
209 std::set<Function*> Functions;
210 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
211 Function *CMF = cast<Function>(VMap[Funcs[i]]);
212 assert(CMF && "Function not in module?!");
213 assert(CMF->getFunctionType() == Funcs[i]->getFunctionType() && "wrong ty");
214 assert(CMF->getName() == Funcs[i]->getName() && "wrong name");
215 Functions.insert(CMF);
218 outs() << "Checking for crash with only these functions: ";
219 PrintFunctionList(Funcs);
222 // Loop over and delete any functions which we aren't supposed to be playing
224 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
225 if (!I->isDeclaration() && !Functions.count(I))
226 DeleteFunctionBody(I);
228 // Try running the hacked up program...
230 BD.setNewProgram(M); // It crashed, keep the trimmed version...
232 // Make sure to use function pointers that point into the now-current
234 Funcs.assign(Functions.begin(), Functions.end());
243 /// ReduceCrashingBlocks reducer - This works by setting the terminators of
244 /// all terminators except the specified basic blocks to a 'ret' instruction,
245 /// then running the simplify-cfg pass. This has the effect of chopping up
246 /// the CFG really fast which can reduce large functions quickly.
248 class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
250 bool (*TestFn)(const BugDriver &, Module *);
252 ReduceCrashingBlocks(BugDriver &bd,
253 bool (*testFn)(const BugDriver &, Module *))
254 : BD(bd), TestFn(testFn) {}
256 TestResult doTest(std::vector<const BasicBlock*> &Prefix,
257 std::vector<const BasicBlock*> &Kept,
258 std::string &Error) override {
259 if (!Kept.empty() && TestBlocks(Kept))
261 if (!Prefix.empty() && TestBlocks(Prefix))
266 bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
270 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
271 // Clone the program to try hacking it apart...
272 ValueToValueMapTy VMap;
273 Module *M = CloneModule(BD.getProgram(), VMap);
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>(VMap[BBs[i]]));
280 outs() << "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 outs() << " " << BBs[i]->getName();
285 if (NumPrint < Blocks.size())
286 outs() << "... <" << Blocks.size() << " total>";
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);
298 TerminatorInst *BBTerm = BB->getTerminator();
300 if (!BB->getTerminator()->getType()->isVoidTy())
301 BBTerm->replaceAllUsesWith(Constant::getNullValue(BBTerm->getType()));
303 // Replace the old terminator instruction.
304 BB->getInstList().pop_back();
305 new UnreachableInst(BB->getContext(), BB);
308 // The CFG Simplifier pass may delete one of the basic blocks we are
309 // interested in. If it does we need to take the block out of the list. Make
310 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
311 // This won't work well if blocks are unnamed, but that is just the risk we
313 std::vector<std::pair<std::string, std::string> > BlockInfo;
315 for (SmallPtrSet<BasicBlock*, 8>::iterator I = Blocks.begin(),
316 E = Blocks.end(); I != E; ++I)
317 BlockInfo.push_back(std::make_pair((*I)->getParent()->getName(),
320 // Now run the CFG simplify pass on the function...
321 std::vector<std::string> Passes;
322 Passes.push_back("simplifycfg");
323 Passes.push_back("verify");
324 Module *New = BD.runPassesOn(M, Passes);
327 errs() << "simplifycfg failed!\n";
332 // Try running on the hacked up program...
334 BD.setNewProgram(M); // It crashed, keep the trimmed version...
336 // Make sure to use basic block pointers that point into the now-current
337 // module, and that they don't include any deleted blocks.
339 const ValueSymbolTable &GST = M->getValueSymbolTable();
340 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
341 Function *F = cast<Function>(GST.lookup(BlockInfo[i].first));
342 ValueSymbolTable &ST = F->getValueSymbolTable();
343 Value* V = ST.lookup(BlockInfo[i].second);
344 if (V && V->getType() == Type::getLabelTy(V->getContext()))
345 BBs.push_back(cast<BasicBlock>(V));
349 delete M; // It didn't crash, try something else.
354 /// ReduceCrashingInstructions reducer - This works by removing the specified
355 /// non-terminator instructions and replacing them with undef.
357 class ReduceCrashingInstructions : public ListReducer<const Instruction*> {
359 bool (*TestFn)(const BugDriver &, Module *);
361 ReduceCrashingInstructions(BugDriver &bd,
362 bool (*testFn)(const BugDriver &, Module *))
363 : BD(bd), TestFn(testFn) {}
365 TestResult doTest(std::vector<const Instruction*> &Prefix,
366 std::vector<const Instruction*> &Kept,
367 std::string &Error) override {
368 if (!Kept.empty() && TestInsts(Kept))
370 if (!Prefix.empty() && TestInsts(Prefix))
375 bool TestInsts(std::vector<const Instruction*> &Prefix);
379 bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
381 // Clone the program to try hacking it apart...
382 ValueToValueMapTy VMap;
383 Module *M = CloneModule(BD.getProgram(), VMap);
385 // Convert list to set for fast lookup...
386 SmallPtrSet<Instruction*, 64> Instructions;
387 for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
388 assert(!isa<TerminatorInst>(Insts[i]));
389 Instructions.insert(cast<Instruction>(VMap[Insts[i]]));
392 outs() << "Checking for crash with only " << Instructions.size();
393 if (Instructions.size() == 1)
394 outs() << " instruction: ";
396 outs() << " instructions: ";
398 for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
399 for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
400 for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
401 Instruction *Inst = I++;
402 if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst) &&
403 !isa<LandingPadInst>(Inst)) {
404 if (!Inst->getType()->isVoidTy())
405 Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
406 Inst->eraseFromParent();
410 // Verify that this is still valid.
412 Passes.add(createVerifierPass());
413 Passes.add(createDebugInfoVerifierPass());
416 // Try running on the hacked up program...
418 BD.setNewProgram(M); // It crashed, keep the trimmed version...
420 // Make sure to use instruction pointers that point into the now-current
421 // module, and that they don't include any deleted blocks.
423 for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
424 E = Instructions.end(); I != E; ++I)
428 delete M; // It didn't crash, try something else.
432 /// DebugACrash - Given a predicate that determines whether a component crashes
433 /// on a program, try to destructively reduce the program while still keeping
434 /// the predicate true.
435 static bool DebugACrash(BugDriver &BD,
436 bool (*TestFn)(const BugDriver &, Module *),
437 std::string &Error) {
438 // See if we can get away with nuking some of the global variable initializers
441 BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
442 // Now try to reduce the number of global variable initializers in the
443 // module to something small.
444 Module *M = CloneModule(BD.getProgram());
445 bool DeletedInit = false;
447 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
449 if (I->hasInitializer()) {
450 I->setInitializer(nullptr);
451 I->setLinkage(GlobalValue::ExternalLinkage);
456 delete M; // No change made...
458 // See if the program still causes a crash...
459 outs() << "\nChecking to see if we can delete global inits: ";
461 if (TestFn(BD, M)) { // Still crashes?
463 outs() << "\n*** Able to remove all global initializers!\n";
464 } else { // No longer crashes?
465 outs() << " - Removing all global inits hides problem!\n";
468 std::vector<GlobalVariable*> GVs;
470 for (Module::global_iterator I = BD.getProgram()->global_begin(),
471 E = BD.getProgram()->global_end(); I != E; ++I)
472 if (I->hasInitializer())
475 if (GVs.size() > 1 && !BugpointIsInterrupted) {
476 outs() << "\n*** Attempting to reduce the number of global "
477 << "variables in the testcase\n";
479 unsigned OldSize = GVs.size();
480 ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs, Error);
484 if (GVs.size() < OldSize)
485 BD.EmitProgressBitcode(BD.getProgram(), "reduced-global-variables");
491 // Now try to reduce the number of functions in the module to something small.
492 std::vector<Function*> Functions;
493 for (Module::iterator I = BD.getProgram()->begin(),
494 E = BD.getProgram()->end(); I != E; ++I)
495 if (!I->isDeclaration())
496 Functions.push_back(I);
498 if (Functions.size() > 1 && !BugpointIsInterrupted) {
499 outs() << "\n*** Attempting to reduce the number of functions "
502 unsigned OldSize = Functions.size();
503 ReduceCrashingFunctions(BD, TestFn).reduceList(Functions, Error);
505 if (Functions.size() < OldSize)
506 BD.EmitProgressBitcode(BD.getProgram(), "reduced-function");
509 // Attempt to delete entire basic blocks at a time to speed up
510 // convergence... this actually works by setting the terminator of the blocks
511 // to a return instruction then running simplifycfg, which can potentially
512 // shrinks the code dramatically quickly
514 if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
515 std::vector<const BasicBlock*> Blocks;
516 for (Module::const_iterator I = BD.getProgram()->begin(),
517 E = BD.getProgram()->end(); I != E; ++I)
518 for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
519 Blocks.push_back(FI);
520 unsigned OldSize = Blocks.size();
521 ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks, Error);
522 if (Blocks.size() < OldSize)
523 BD.EmitProgressBitcode(BD.getProgram(), "reduced-blocks");
526 // Attempt to delete instructions using bisection. This should help out nasty
527 // cases with large basic blocks where the problem is at one end.
528 if (!BugpointIsInterrupted) {
529 std::vector<const Instruction*> Insts;
530 for (Module::const_iterator MI = BD.getProgram()->begin(),
531 ME = BD.getProgram()->end(); MI != ME; ++MI)
532 for (Function::const_iterator FI = MI->begin(), FE = MI->end(); FI != FE;
534 for (BasicBlock::const_iterator I = FI->begin(), E = FI->end();
536 if (!isa<TerminatorInst>(I))
539 ReduceCrashingInstructions(BD, TestFn).reduceList(Insts, Error);
542 // FIXME: This should use the list reducer to converge faster by deleting
543 // larger chunks of instructions at a time!
544 unsigned Simplification = 2;
546 if (BugpointIsInterrupted) break;
548 outs() << "\n*** Attempting to reduce testcase by deleting instruc"
549 << "tions: Simplification Level #" << Simplification << '\n';
551 // Now that we have deleted the functions that are unnecessary for the
552 // program, try to remove instructions that are not necessary to cause the
553 // crash. To do this, we loop through all of the instructions in the
554 // remaining functions, deleting them (replacing any values produced with
555 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
556 // still triggers failure, keep deleting until we cannot trigger failure
559 unsigned InstructionsToSkipBeforeDeleting = 0;
562 // Loop over all of the (non-terminator) instructions remaining in the
563 // function, attempting to delete them.
564 unsigned CurInstructionNum = 0;
565 for (Module::const_iterator FI = BD.getProgram()->begin(),
566 E = BD.getProgram()->end(); FI != E; ++FI)
567 if (!FI->isDeclaration())
568 for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
570 for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
571 I != E; ++I, ++CurInstructionNum) {
572 if (InstructionsToSkipBeforeDeleting) {
573 --InstructionsToSkipBeforeDeleting;
575 if (BugpointIsInterrupted) goto ExitLoops;
577 if (isa<LandingPadInst>(I))
580 outs() << "Checking instruction: " << *I;
581 Module *M = BD.deleteInstructionFromProgram(I, Simplification);
583 // Find out if the pass still crashes on this pass...
585 // Yup, it does, we delete the old module, and continue trying
586 // to reduce the testcase...
588 InstructionsToSkipBeforeDeleting = CurInstructionNum;
589 goto TryAgain; // I wish I had a multi-level break here!
592 // This pass didn't crash without this instruction, try the next
598 if (InstructionsToSkipBeforeDeleting) {
599 InstructionsToSkipBeforeDeleting = 0;
603 } while (Simplification);
606 // Try to clean up the testcase by running funcresolve and globaldce...
607 if (!BugpointIsInterrupted) {
608 outs() << "\n*** Attempting to perform final cleanups: ";
609 Module *M = CloneModule(BD.getProgram());
610 M = BD.performFinalCleanups(M, true);
612 // Find out if the pass still crashes on the cleaned up program...
614 BD.setNewProgram(M); // Yup, it does, keep the reduced version...
620 BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplified");
625 static bool TestForOptimizerCrash(const BugDriver &BD, Module *M) {
626 return BD.runPasses(M);
629 /// debugOptimizerCrash - This method is called when some pass crashes on input.
630 /// It attempts to prune down the testcase to something reasonable, and figure
631 /// out exactly which pass is crashing.
633 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
634 outs() << "\n*** Debugging optimizer crash!\n";
637 // Reduce the list of passes which causes the optimizer to crash...
638 if (!BugpointIsInterrupted)
639 ReducePassList(*this).reduceList(PassesToRun, Error);
640 assert(Error.empty());
642 outs() << "\n*** Found crashing pass"
643 << (PassesToRun.size() == 1 ? ": " : "es: ")
644 << getPassesString(PassesToRun) << '\n';
646 EmitProgressBitcode(Program, ID);
648 bool Success = DebugACrash(*this, TestForOptimizerCrash, Error);
649 assert(Error.empty());
653 static bool TestForCodeGenCrash(const BugDriver &BD, Module *M) {
655 BD.compileProgram(M, &Error);
656 if (!Error.empty()) {
657 errs() << "<crash>\n";
658 return true; // Tool is still crashing.
664 /// debugCodeGeneratorCrash - This method is called when the code generator
665 /// crashes on an input. It attempts to reduce the input as much as possible
666 /// while still causing the code generator to crash.
667 bool BugDriver::debugCodeGeneratorCrash(std::string &Error) {
668 errs() << "*** Debugging code generator crash!\n";
670 return DebugACrash(*this, TestForCodeGenCrash, Error);