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);
60 ReducePassList::TestResult
61 ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
62 std::vector<const PassInfo*> &Suffix) {
63 sys::Path PrefixOutput;
64 Module *OrigProgram = 0;
65 if (!Prefix.empty()) {
66 outs() << "Checking to see if these passes crash: "
67 << getPassesString(Prefix) << ": ";
68 std::string PfxOutput;
69 if (BD.runPasses(Prefix, PfxOutput))
72 PrefixOutput.set(PfxOutput);
73 OrigProgram = BD.Program;
75 BD.Program = ParseInputFile(PrefixOutput.toString(), BD.getContext());
76 if (BD.Program == 0) {
77 errs() << BD.getToolName() << ": Error reading bitcode file '"
78 << PrefixOutput << "'!\n";
81 PrefixOutput.eraseFromDisk();
84 outs() << "Checking to see if these passes crash: "
85 << getPassesString(Suffix) << ": ";
87 if (BD.runPasses(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)(BugDriver &, Module *);
109 ReduceCrashingGlobalVariables(BugDriver &bd,
110 bool (*testFn)(BugDriver&, Module*))
111 : BD(bd), TestFn(testFn) {}
113 virtual TestResult doTest(std::vector<GlobalVariable*>& Prefix,
114 std::vector<GlobalVariable*>& Kept) {
115 if (!Kept.empty() && TestGlobalVariables(Kept))
118 if (!Prefix.empty() && TestGlobalVariables(Prefix))
124 bool TestGlobalVariables(std::vector<GlobalVariable*>& GVs);
129 ReduceCrashingGlobalVariables::TestGlobalVariables(
130 std::vector<GlobalVariable*>& GVs) {
131 // Clone the program to try hacking it apart...
132 DenseMap<const Value*, Value*> ValueMap;
133 Module *M = CloneModule(BD.getProgram(), ValueMap);
135 // Convert list to set for fast lookup...
136 std::set<GlobalVariable*> GVSet;
138 for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
139 GlobalVariable* CMGV = cast<GlobalVariable>(ValueMap[GVs[i]]);
140 assert(CMGV && "Global Variable not in module?!");
144 outs() << "Checking for crash with only these global variables: ";
145 PrintGlobalVariableList(GVs);
148 // Loop over and delete any global variables which we aren't supposed to be
150 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
152 if (I->hasInitializer() && !GVSet.count(I)) {
153 I->setInitializer(0);
154 I->setLinkage(GlobalValue::ExternalLinkage);
157 // Try running the hacked up program...
159 BD.setNewProgram(M); // It crashed, keep the trimmed version...
161 // Make sure to use global variable pointers that point into the now-current
163 GVs.assign(GVSet.begin(), GVSet.end());
172 /// ReduceCrashingFunctions reducer - This works by removing functions and
173 /// seeing if the program still crashes. If it does, then keep the newer,
176 class ReduceCrashingFunctions : public ListReducer<Function*> {
178 bool (*TestFn)(BugDriver &, Module *);
180 ReduceCrashingFunctions(BugDriver &bd,
181 bool (*testFn)(BugDriver &, Module *))
182 : BD(bd), TestFn(testFn) {}
184 virtual TestResult doTest(std::vector<Function*> &Prefix,
185 std::vector<Function*> &Kept) {
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) {
199 //if main isn't present, claim there is no problem
200 if (KeepMain && find(Funcs.begin(), Funcs.end(),
201 BD.getProgram()->getFunction("main")) == Funcs.end())
204 // Clone the program to try hacking it apart...
205 DenseMap<const Value*, Value*> ValueMap;
206 Module *M = CloneModule(BD.getProgram(), ValueMap);
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>(ValueMap[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)(BugDriver &, Module *);
252 ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
253 : BD(bd), TestFn(testFn) {}
255 virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
256 std::vector<const BasicBlock*> &Kept) {
257 if (!Kept.empty() && TestBlocks(Kept))
259 if (!Prefix.empty() && TestBlocks(Prefix))
264 bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
268 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
269 // Clone the program to try hacking it apart...
270 DenseMap<const Value*, Value*> ValueMap;
271 Module *M = CloneModule(BD.getProgram(), ValueMap);
273 // Convert list to set for fast lookup...
274 SmallPtrSet<BasicBlock*, 8> Blocks;
275 for (unsigned i = 0, e = BBs.size(); i != e; ++i)
276 Blocks.insert(cast<BasicBlock>(ValueMap[BBs[i]]));
278 outs() << "Checking for crash with only these blocks:";
279 unsigned NumPrint = Blocks.size();
280 if (NumPrint > 10) NumPrint = 10;
281 for (unsigned i = 0, e = NumPrint; i != e; ++i)
282 outs() << " " << BBs[i]->getName();
283 if (NumPrint < Blocks.size())
284 outs() << "... <" << Blocks.size() << " total>";
287 // Loop over and delete any hack up any blocks that are not listed...
288 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
289 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
290 if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
291 // Loop over all of the successors of this block, deleting any PHI nodes
292 // that might include it.
293 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
294 (*SI)->removePredecessor(BB);
296 TerminatorInst *BBTerm = BB->getTerminator();
298 if (isa<StructType>(BBTerm->getType()))
299 BBTerm->replaceAllUsesWith(UndefValue::get(BBTerm->getType()));
300 else if (BB->getTerminator()->getType() != Type::VoidTy)
301 BBTerm->replaceAllUsesWith(Constant::getNullValue(BBTerm->getType()));
303 // Replace the old terminator instruction.
304 BB->getInstList().pop_back();
305 new UnreachableInst(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<Function*, 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(), (*I)->getName()));
319 // Now run the CFG simplify pass on the function...
321 Passes.add(createCFGSimplificationPass());
322 Passes.add(createVerifierPass());
325 // Try running on the hacked up program...
327 BD.setNewProgram(M); // It crashed, keep the trimmed version...
329 // Make sure to use basic block pointers that point into the now-current
330 // module, and that they don't include any deleted blocks.
332 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
333 ValueSymbolTable &ST = BlockInfo[i].first->getValueSymbolTable();
334 Value* V = ST.lookup(BlockInfo[i].second);
335 if (V && V->getType() == Type::LabelTy)
336 BBs.push_back(cast<BasicBlock>(V));
340 delete M; // It didn't crash, try something else.
345 /// ReduceCrashingInstructions reducer - This works by removing the specified
346 /// non-terminator instructions and replacing them with undef.
348 class ReduceCrashingInstructions : public ListReducer<const Instruction*> {
350 bool (*TestFn)(BugDriver &, Module *);
352 ReduceCrashingInstructions(BugDriver &bd, bool (*testFn)(BugDriver &,
354 : BD(bd), TestFn(testFn) {}
356 virtual TestResult doTest(std::vector<const Instruction*> &Prefix,
357 std::vector<const Instruction*> &Kept) {
358 if (!Kept.empty() && TestInsts(Kept))
360 if (!Prefix.empty() && TestInsts(Prefix))
365 bool TestInsts(std::vector<const Instruction*> &Prefix);
369 bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
371 // Clone the program to try hacking it apart...
372 DenseMap<const Value*, Value*> ValueMap;
373 Module *M = CloneModule(BD.getProgram(), ValueMap);
375 // Convert list to set for fast lookup...
376 SmallPtrSet<Instruction*, 64> Instructions;
377 for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
378 assert(!isa<TerminatorInst>(Insts[i]));
379 Instructions.insert(cast<Instruction>(ValueMap[Insts[i]]));
382 outs() << "Checking for crash with only " << Instructions.size();
383 if (Instructions.size() == 1)
384 outs() << " instruction: ";
386 outs() << " instructions: ";
388 for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
389 for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
390 for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
391 Instruction *Inst = I++;
392 if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst)) {
393 if (Inst->getType() != Type::VoidTy)
394 Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
395 Inst->eraseFromParent();
399 // Verify that this is still valid.
401 Passes.add(createVerifierPass());
404 // Try running on the hacked up program...
406 BD.setNewProgram(M); // It crashed, keep the trimmed version...
408 // Make sure to use instruction pointers that point into the now-current
409 // module, and that they don't include any deleted blocks.
411 for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
412 E = Instructions.end(); I != E; ++I)
416 delete M; // It didn't crash, try something else.
420 /// DebugACrash - Given a predicate that determines whether a component crashes
421 /// on a program, try to destructively reduce the program while still keeping
422 /// the predicate true.
423 static bool DebugACrash(BugDriver &BD, bool (*TestFn)(BugDriver &, Module *)) {
424 // See if we can get away with nuking some of the global variable initializers
427 BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
428 // Now try to reduce the number of global variable initializers in the
429 // module to something small.
430 Module *M = CloneModule(BD.getProgram());
431 bool DeletedInit = false;
433 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
435 if (I->hasInitializer()) {
436 I->setInitializer(0);
437 I->setLinkage(GlobalValue::ExternalLinkage);
442 delete M; // No change made...
444 // See if the program still causes a crash...
445 outs() << "\nChecking to see if we can delete global inits: ";
447 if (TestFn(BD, M)) { // Still crashes?
449 outs() << "\n*** Able to remove all global initializers!\n";
450 } else { // No longer crashes?
451 outs() << " - Removing all global inits hides problem!\n";
454 std::vector<GlobalVariable*> GVs;
456 for (Module::global_iterator I = BD.getProgram()->global_begin(),
457 E = BD.getProgram()->global_end(); I != E; ++I)
458 if (I->hasInitializer())
461 if (GVs.size() > 1 && !BugpointIsInterrupted) {
462 outs() << "\n*** Attempting to reduce the number of global "
463 << "variables in the testcase\n";
465 unsigned OldSize = GVs.size();
466 ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs);
468 if (GVs.size() < OldSize)
469 BD.EmitProgressBitcode("reduced-global-variables");
475 // Now try to reduce the number of functions in the module to something small.
476 std::vector<Function*> Functions;
477 for (Module::iterator I = BD.getProgram()->begin(),
478 E = BD.getProgram()->end(); I != E; ++I)
479 if (!I->isDeclaration())
480 Functions.push_back(I);
482 if (Functions.size() > 1 && !BugpointIsInterrupted) {
483 outs() << "\n*** Attempting to reduce the number of functions "
486 unsigned OldSize = Functions.size();
487 ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
489 if (Functions.size() < OldSize)
490 BD.EmitProgressBitcode("reduced-function");
493 // Attempt to delete entire basic blocks at a time to speed up
494 // convergence... this actually works by setting the terminator of the blocks
495 // to a return instruction then running simplifycfg, which can potentially
496 // shrinks the code dramatically quickly
498 if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
499 std::vector<const BasicBlock*> Blocks;
500 for (Module::const_iterator I = BD.getProgram()->begin(),
501 E = BD.getProgram()->end(); I != E; ++I)
502 for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
503 Blocks.push_back(FI);
504 unsigned OldSize = Blocks.size();
505 ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
506 if (Blocks.size() < OldSize)
507 BD.EmitProgressBitcode("reduced-blocks");
510 // Attempt to delete instructions using bisection. This should help out nasty
511 // cases with large basic blocks where the problem is at one end.
512 if (!BugpointIsInterrupted) {
513 std::vector<const Instruction*> Insts;
514 for (Module::const_iterator MI = BD.getProgram()->begin(),
515 ME = BD.getProgram()->end(); MI != ME; ++MI)
516 for (Function::const_iterator FI = MI->begin(), FE = MI->end(); FI != FE;
518 for (BasicBlock::const_iterator I = FI->begin(), E = FI->end();
520 if (!isa<TerminatorInst>(I))
523 ReduceCrashingInstructions(BD, TestFn).reduceList(Insts);
526 // FIXME: This should use the list reducer to converge faster by deleting
527 // larger chunks of instructions at a time!
528 unsigned Simplification = 2;
530 if (BugpointIsInterrupted) break;
532 outs() << "\n*** Attempting to reduce testcase by deleting instruc"
533 << "tions: Simplification Level #" << Simplification << '\n';
535 // Now that we have deleted the functions that are unnecessary for the
536 // program, try to remove instructions that are not necessary to cause the
537 // crash. To do this, we loop through all of the instructions in the
538 // remaining functions, deleting them (replacing any values produced with
539 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
540 // still triggers failure, keep deleting until we cannot trigger failure
543 unsigned InstructionsToSkipBeforeDeleting = 0;
546 // Loop over all of the (non-terminator) instructions remaining in the
547 // function, attempting to delete them.
548 unsigned CurInstructionNum = 0;
549 for (Module::const_iterator FI = BD.getProgram()->begin(),
550 E = BD.getProgram()->end(); FI != E; ++FI)
551 if (!FI->isDeclaration())
552 for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
554 for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
555 I != E; ++I, ++CurInstructionNum)
556 if (InstructionsToSkipBeforeDeleting) {
557 --InstructionsToSkipBeforeDeleting;
559 if (BugpointIsInterrupted) goto ExitLoops;
561 outs() << "Checking instruction: " << *I;
562 Module *M = BD.deleteInstructionFromProgram(I, Simplification);
564 // Find out if the pass still crashes on this pass...
566 // Yup, it does, we delete the old module, and continue trying
567 // to reduce the testcase...
569 InstructionsToSkipBeforeDeleting = CurInstructionNum;
570 goto TryAgain; // I wish I had a multi-level break here!
573 // This pass didn't crash without this instruction, try the next
578 if (InstructionsToSkipBeforeDeleting) {
579 InstructionsToSkipBeforeDeleting = 0;
583 } while (Simplification);
586 // Try to clean up the testcase by running funcresolve and globaldce...
587 if (!BugpointIsInterrupted) {
588 outs() << "\n*** Attempting to perform final cleanups: ";
589 Module *M = CloneModule(BD.getProgram());
590 M = BD.performFinalCleanups(M, true);
592 // Find out if the pass still crashes on the cleaned up program...
594 BD.setNewProgram(M); // Yup, it does, keep the reduced version...
600 BD.EmitProgressBitcode("reduced-simplified");
605 static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
606 return BD.runPasses(M);
609 /// debugOptimizerCrash - This method is called when some pass crashes on input.
610 /// It attempts to prune down the testcase to something reasonable, and figure
611 /// out exactly which pass is crashing.
613 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
614 outs() << "\n*** Debugging optimizer crash!\n";
616 // Reduce the list of passes which causes the optimizer to crash...
617 if (!BugpointIsInterrupted)
618 ReducePassList(*this).reduceList(PassesToRun);
620 outs() << "\n*** Found crashing pass"
621 << (PassesToRun.size() == 1 ? ": " : "es: ")
622 << getPassesString(PassesToRun) << '\n';
624 EmitProgressBitcode(ID);
626 return DebugACrash(*this, TestForOptimizerCrash);
629 static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
631 BD.compileProgram(M);
634 } catch (ToolExecutionError &) {
635 errs() << "<crash>\n";
636 return true; // Tool is still crashing.
640 /// debugCodeGeneratorCrash - This method is called when the code generator
641 /// crashes on an input. It attempts to reduce the input as much as possible
642 /// while still causing the code generator to crash.
643 bool BugDriver::debugCodeGeneratorCrash() {
644 errs() << "*** Debugging code generator crash!\n";
646 return DebugACrash(*this, TestForCodeGenCrash);