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"
38 cl::desc("Force function reduction to keep main"),
41 NoGlobalRM ("disable-global-remove",
42 cl::desc("Do not remove global variables"),
47 class ReducePassList : public ListReducer<const PassInfo*> {
50 ReducePassList(BugDriver &bd) : BD(bd) {}
52 // doTest - Return true iff running the "removed" passes succeeds, and
53 // running the "Kept" passes fail when run on the output of the "removed"
54 // passes. If we return true, we update the current module of bugpoint.
56 virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
57 std::vector<const PassInfo*> &Kept);
61 ReducePassList::TestResult
62 ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
63 std::vector<const PassInfo*> &Suffix) {
64 sys::Path PrefixOutput;
65 Module *OrigProgram = 0;
66 if (!Prefix.empty()) {
67 std::cout << "Checking to see if these passes crash: "
68 << getPassesString(Prefix) << ": ";
69 std::string PfxOutput;
70 if (BD.runPasses(Prefix, PfxOutput))
73 PrefixOutput.set(PfxOutput);
74 OrigProgram = BD.Program;
76 BD.Program = ParseInputFile(PrefixOutput.toString());
77 if (BD.Program == 0) {
78 std::cerr << BD.getToolName() << ": Error reading bitcode file '"
79 << PrefixOutput << "'!\n";
82 PrefixOutput.eraseFromDisk();
85 std::cout << "Checking to see if these passes crash: "
86 << getPassesString(Suffix) << ": ";
88 if (BD.runPasses(Suffix)) {
89 delete OrigProgram; // The suffix crashes alone...
93 // Nothing failed, restore state...
96 BD.Program = OrigProgram;
102 /// ReduceCrashingGlobalVariables - This works by removing the global
103 /// variable's initializer and seeing if the program still crashes. If it
104 /// does, then we keep that program and try again.
106 class ReduceCrashingGlobalVariables : public ListReducer<GlobalVariable*> {
108 bool (*TestFn)(BugDriver &, Module *);
110 ReduceCrashingGlobalVariables(BugDriver &bd,
111 bool (*testFn)(BugDriver&, Module*))
112 : BD(bd), TestFn(testFn) {}
114 virtual TestResult doTest(std::vector<GlobalVariable*>& Prefix,
115 std::vector<GlobalVariable*>& Kept) {
116 if (!Kept.empty() && TestGlobalVariables(Kept))
119 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 std::cout << "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()) {
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 if (!Kept.empty() && TestFuncs(Kept))
189 if (!Prefix.empty() && TestFuncs(Prefix))
194 bool TestFuncs(std::vector<Function*> &Prefix);
198 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
200 //if main isn't present, claim there is no problem
201 if (KeepMain && find(Funcs.begin(), Funcs.end(),
202 BD.getProgram()->getFunction("main")) == Funcs.end())
205 // Clone the program to try hacking it apart...
206 DenseMap<const Value*, Value*> ValueMap;
207 Module *M = CloneModule(BD.getProgram(), ValueMap);
209 // Convert list to set for fast lookup...
210 std::set<Function*> Functions;
211 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
212 Function *CMF = cast<Function>(ValueMap[Funcs[i]]);
213 assert(CMF && "Function not in module?!");
214 assert(CMF->getFunctionType() == Funcs[i]->getFunctionType() && "wrong ty");
215 assert(CMF->getName() == Funcs[i]->getName() && "wrong name");
216 Functions.insert(CMF);
219 std::cout << "Checking for crash with only these functions: ";
220 PrintFunctionList(Funcs);
223 // Loop over and delete any functions which we aren't supposed to be playing
225 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
226 if (!I->isDeclaration() && !Functions.count(I))
227 DeleteFunctionBody(I);
229 // Try running the hacked up program...
231 BD.setNewProgram(M); // It crashed, keep the trimmed version...
233 // Make sure to use function pointers that point into the now-current
235 Funcs.assign(Functions.begin(), Functions.end());
244 /// ReduceCrashingBlocks reducer - This works by setting the terminators of
245 /// all terminators except the specified basic blocks to a 'ret' instruction,
246 /// then running the simplify-cfg pass. This has the effect of chopping up
247 /// the CFG really fast which can reduce large functions quickly.
249 class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
251 bool (*TestFn)(BugDriver &, Module *);
253 ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
254 : BD(bd), TestFn(testFn) {}
256 virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
257 std::vector<const BasicBlock*> &Kept) {
258 if (!Kept.empty() && TestBlocks(Kept))
260 if (!Prefix.empty() && TestBlocks(Prefix))
265 bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
269 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
270 // Clone the program to try hacking it apart...
271 DenseMap<const Value*, Value*> ValueMap;
272 Module *M = CloneModule(BD.getProgram(), ValueMap);
274 // Convert list to set for fast lookup...
275 SmallPtrSet<BasicBlock*, 8> Blocks;
276 for (unsigned i = 0, e = BBs.size(); i != e; ++i)
277 Blocks.insert(cast<BasicBlock>(ValueMap[BBs[i]]));
279 std::cout << "Checking for crash with only these blocks:";
280 unsigned NumPrint = Blocks.size();
281 if (NumPrint > 10) NumPrint = 10;
282 for (unsigned i = 0, e = NumPrint; i != e; ++i)
283 std::cout << " " << BBs[i]->getName();
284 if (NumPrint < Blocks.size())
285 std::cout << "... <" << Blocks.size() << " total>";
288 // Loop over and delete any hack up any blocks that are not listed...
289 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
290 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
291 if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
292 // Loop over all of the successors of this block, deleting any PHI nodes
293 // that might include it.
294 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
295 (*SI)->removePredecessor(BB);
297 TerminatorInst *BBTerm = BB->getTerminator();
299 if (isa<StructType>(BBTerm->getType()))
300 BBTerm->replaceAllUsesWith(UndefValue::get(BBTerm->getType()));
301 else if (BB->getTerminator()->getType() != Type::VoidTy)
302 BBTerm->replaceAllUsesWith(Constant::getNullValue(BBTerm->getType()));
304 // Replace the old terminator instruction.
305 BB->getInstList().pop_back();
306 new UnreachableInst(BB);
309 // The CFG Simplifier pass may delete one of the basic blocks we are
310 // interested in. If it does we need to take the block out of the list. Make
311 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
312 // This won't work well if blocks are unnamed, but that is just the risk we
314 std::vector<std::pair<Function*, std::string> > BlockInfo;
316 for (SmallPtrSet<BasicBlock*, 8>::iterator I = Blocks.begin(),
317 E = Blocks.end(); I != E; ++I)
318 BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
320 // Now run the CFG simplify pass on the function...
322 Passes.add(createCFGSimplificationPass());
323 Passes.add(createVerifierPass());
326 // Try running on the hacked up program...
328 BD.setNewProgram(M); // It crashed, keep the trimmed version...
330 // Make sure to use basic block pointers that point into the now-current
331 // module, and that they don't include any deleted blocks.
333 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
334 ValueSymbolTable &ST = BlockInfo[i].first->getValueSymbolTable();
335 Value* V = ST.lookup(BlockInfo[i].second);
336 if (V && V->getType() == Type::LabelTy)
337 BBs.push_back(cast<BasicBlock>(V));
341 delete M; // It didn't crash, try something else.
345 /// DebugACrash - Given a predicate that determines whether a component crashes
346 /// on a program, try to destructively reduce the program while still keeping
347 /// the predicate true.
348 static bool DebugACrash(BugDriver &BD, bool (*TestFn)(BugDriver &, Module *)) {
349 // See if we can get away with nuking some of the global variable initializers
352 BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
353 // Now try to reduce the number of global variable initializers in the
354 // module to something small.
355 Module *M = CloneModule(BD.getProgram());
356 bool DeletedInit = false;
358 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
360 if (I->hasInitializer()) {
361 I->setInitializer(0);
362 I->setLinkage(GlobalValue::ExternalLinkage);
367 delete M; // No change made...
369 // See if the program still causes a crash...
370 std::cout << "\nChecking to see if we can delete global inits: ";
372 if (TestFn(BD, M)) { // Still crashes?
374 std::cout << "\n*** Able to remove all global initializers!\n";
375 } else { // No longer crashes?
376 std::cout << " - Removing all global inits hides problem!\n";
379 std::vector<GlobalVariable*> GVs;
381 for (Module::global_iterator I = BD.getProgram()->global_begin(),
382 E = BD.getProgram()->global_end(); I != E; ++I)
383 if (I->hasInitializer())
386 if (GVs.size() > 1 && !BugpointIsInterrupted) {
387 std::cout << "\n*** Attempting to reduce the number of global "
388 << "variables in the testcase\n";
390 unsigned OldSize = GVs.size();
391 ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs);
393 if (GVs.size() < OldSize)
394 BD.EmitProgressBitcode("reduced-global-variables");
400 // Now try to reduce the number of functions in the module to something small.
401 std::vector<Function*> Functions;
402 for (Module::iterator I = BD.getProgram()->begin(),
403 E = BD.getProgram()->end(); I != E; ++I)
404 if (!I->isDeclaration())
405 Functions.push_back(I);
407 if (Functions.size() > 1 && !BugpointIsInterrupted) {
408 std::cout << "\n*** Attempting to reduce the number of functions "
411 unsigned OldSize = Functions.size();
412 ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
414 if (Functions.size() < OldSize)
415 BD.EmitProgressBitcode("reduced-function");
418 // Attempt to delete entire basic blocks at a time to speed up
419 // convergence... this actually works by setting the terminator of the blocks
420 // to a return instruction then running simplifycfg, which can potentially
421 // shrinks the code dramatically quickly
423 if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
424 std::vector<const BasicBlock*> Blocks;
425 for (Module::const_iterator I = BD.getProgram()->begin(),
426 E = BD.getProgram()->end(); I != E; ++I)
427 for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
428 Blocks.push_back(FI);
429 ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
432 // FIXME: This should use the list reducer to converge faster by deleting
433 // larger chunks of instructions at a time!
434 unsigned Simplification = 2;
436 if (BugpointIsInterrupted) break;
438 std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
439 << "tions: Simplification Level #" << Simplification << '\n';
441 // Now that we have deleted the functions that are unnecessary for the
442 // program, try to remove instructions that are not necessary to cause the
443 // crash. To do this, we loop through all of the instructions in the
444 // remaining functions, deleting them (replacing any values produced with
445 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
446 // still triggers failure, keep deleting until we cannot trigger failure
449 unsigned InstructionsToSkipBeforeDeleting = 0;
452 // Loop over all of the (non-terminator) instructions remaining in the
453 // function, attempting to delete them.
454 unsigned CurInstructionNum = 0;
455 for (Module::const_iterator FI = BD.getProgram()->begin(),
456 E = BD.getProgram()->end(); FI != E; ++FI)
457 if (!FI->isDeclaration())
458 for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
460 for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
461 I != E; ++I, ++CurInstructionNum)
462 if (InstructionsToSkipBeforeDeleting) {
463 --InstructionsToSkipBeforeDeleting;
465 if (BugpointIsInterrupted) goto ExitLoops;
467 std::cout << "Checking instruction: " << *I;
468 Module *M = BD.deleteInstructionFromProgram(I, Simplification);
470 // Find out if the pass still crashes on this pass...
472 // Yup, it does, we delete the old module, and continue trying
473 // to reduce the testcase...
475 InstructionsToSkipBeforeDeleting = CurInstructionNum;
476 goto TryAgain; // I wish I had a multi-level break here!
479 // This pass didn't crash without this instruction, try the next
484 if (InstructionsToSkipBeforeDeleting) {
485 InstructionsToSkipBeforeDeleting = 0;
489 } while (Simplification);
492 // Try to clean up the testcase by running funcresolve and globaldce...
493 if (!BugpointIsInterrupted) {
494 std::cout << "\n*** Attempting to perform final cleanups: ";
495 Module *M = CloneModule(BD.getProgram());
496 M = BD.performFinalCleanups(M, true);
498 // Find out if the pass still crashes on the cleaned up program...
500 BD.setNewProgram(M); // Yup, it does, keep the reduced version...
506 BD.EmitProgressBitcode("reduced-simplified");
511 static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
512 return BD.runPasses(M);
515 /// debugOptimizerCrash - This method is called when some pass crashes on input.
516 /// It attempts to prune down the testcase to something reasonable, and figure
517 /// out exactly which pass is crashing.
519 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
520 std::cout << "\n*** Debugging optimizer crash!\n";
522 // Reduce the list of passes which causes the optimizer to crash...
523 if (!BugpointIsInterrupted)
524 ReducePassList(*this).reduceList(PassesToRun);
526 std::cout << "\n*** Found crashing pass"
527 << (PassesToRun.size() == 1 ? ": " : "es: ")
528 << getPassesString(PassesToRun) << '\n';
530 EmitProgressBitcode(ID);
532 return DebugACrash(*this, TestForOptimizerCrash);
535 static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
537 BD.compileProgram(M);
540 } catch (ToolExecutionError &) {
541 std::cerr << "<crash>\n";
542 return true; // Tool is still crashing.
546 /// debugCodeGeneratorCrash - This method is called when the code generator
547 /// crashes on an input. It attempts to reduce the input as much as possible
548 /// while still causing the code generator to crash.
549 bool BugDriver::debugCodeGeneratorCrash() {
550 std::cerr << "*** Debugging code generator crash!\n";
552 return DebugACrash(*this, TestForCodeGenCrash);