1 //===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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/Constant.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/SymbolTable.h"
24 #include "llvm/Analysis/Verifier.h"
25 #include "llvm/Bytecode/Writer.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"),
43 class ReducePassList : public ListReducer<const PassInfo*> {
46 ReducePassList(BugDriver &bd) : BD(bd) {}
48 // doTest - Return true iff running the "removed" passes succeeds, and
49 // running the "Kept" passes fail when run on the output of the "removed"
50 // passes. If we return true, we update the current module of bugpoint.
52 virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
53 std::vector<const PassInfo*> &Kept);
57 ReducePassList::TestResult
58 ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
59 std::vector<const PassInfo*> &Suffix) {
60 sys::Path PrefixOutput;
61 Module *OrigProgram = 0;
62 if (!Prefix.empty()) {
63 std::cout << "Checking to see if these passes crash: "
64 << getPassesString(Prefix) << ": ";
65 std::string PfxOutput;
66 if (BD.runPasses(Prefix, PfxOutput))
69 PrefixOutput.set(PfxOutput);
70 OrigProgram = BD.Program;
72 BD.Program = ParseInputFile(PrefixOutput.toString());
73 if (BD.Program == 0) {
74 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
75 << PrefixOutput << "'!\n";
78 PrefixOutput.eraseFromDisk();
81 std::cout << "Checking to see if these passes crash: "
82 << getPassesString(Suffix) << ": ";
84 if (BD.runPasses(Suffix)) {
85 delete OrigProgram; // The suffix crashes alone...
89 // Nothing failed, restore state...
92 BD.Program = OrigProgram;
98 /// ReduceCrashingGlobalVariables - This works by removing the global
99 /// variable's initializer and seeing if the program still crashes. If it
100 /// does, then we keep that program and try again.
102 class ReduceCrashingGlobalVariables : public ListReducer<GlobalVariable*> {
104 bool (*TestFn)(BugDriver &, Module *);
106 ReduceCrashingGlobalVariables(BugDriver &bd,
107 bool (*testFn)(BugDriver&, Module*))
108 : BD(bd), TestFn(testFn) {}
110 virtual TestResult doTest(std::vector<GlobalVariable*>& Prefix,
111 std::vector<GlobalVariable*>& Kept) {
112 if (!Kept.empty() && TestGlobalVariables(Kept))
115 if (!Prefix.empty() && TestGlobalVariables(Prefix))
121 bool TestGlobalVariables(std::vector<GlobalVariable*>& GVs);
126 ReduceCrashingGlobalVariables::TestGlobalVariables(
127 std::vector<GlobalVariable*>& GVs) {
128 // Clone the program to try hacking it apart...
129 Module *M = CloneModule(BD.getProgram());
131 // Convert list to set for fast lookup...
132 std::set<GlobalVariable*> GVSet;
134 for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
135 GlobalVariable* CMGV = M->getNamedGlobal(GVs[i]->getName());
136 assert(CMGV && "Global Variable not in module?!");
140 std::cout << "Checking for crash with only these global variables: ";
141 PrintGlobalVariableList(GVs);
144 // Loop over and delete any global variables which we aren't supposed to be
146 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
148 if (I->hasInitializer()) {
149 I->setInitializer(0);
150 I->setLinkage(GlobalValue::ExternalLinkage);
153 // Try running the hacked up program...
155 BD.setNewProgram(M); // It crashed, keep the trimmed version...
157 // Make sure to use global variable pointers that point into the now-current
159 GVs.assign(GVSet.begin(), GVSet.end());
168 /// ReduceCrashingFunctions reducer - This works by removing functions and
169 /// seeing if the program still crashes. If it does, then keep the newer,
172 class ReduceCrashingFunctions : public ListReducer<Function*> {
174 bool (*TestFn)(BugDriver &, Module *);
176 ReduceCrashingFunctions(BugDriver &bd,
177 bool (*testFn)(BugDriver &, Module *))
178 : BD(bd), TestFn(testFn) {}
180 virtual TestResult doTest(std::vector<Function*> &Prefix,
181 std::vector<Function*> &Kept) {
182 if (!Kept.empty() && TestFuncs(Kept))
184 if (!Prefix.empty() && TestFuncs(Prefix))
189 bool TestFuncs(std::vector<Function*> &Prefix);
193 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
195 //if main isn't present, claim there is no problem
196 if (KeepMain && find(Funcs.begin(), Funcs.end(),
197 BD.getProgram()->getMainFunction()) == Funcs.end())
200 // Clone the program to try hacking it apart...
201 Module *M = CloneModule(BD.getProgram());
203 // Convert list to set for fast lookup...
204 std::set<Function*> Functions;
205 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
206 // FIXME: bugpoint should add names to all stripped symbols.
207 assert(!Funcs[i]->getName().empty() &&
208 "Bugpoint doesn't work on stripped modules yet PR718!");
209 Function *CMF = M->getFunction(Funcs[i]->getName(),
210 Funcs[i]->getFunctionType());
211 assert(CMF && "Function not in module?!");
212 Functions.insert(CMF);
215 std::cout << "Checking for crash with only these functions: ";
216 PrintFunctionList(Funcs);
219 // Loop over and delete any functions which we aren't supposed to be playing
221 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
222 if (!I->isExternal() && !Functions.count(I))
223 DeleteFunctionBody(I);
225 // Try running the hacked up program...
227 BD.setNewProgram(M); // It crashed, keep the trimmed version...
229 // Make sure to use function pointers that point into the now-current
231 Funcs.assign(Functions.begin(), Functions.end());
240 /// ReduceCrashingBlocks reducer - This works by setting the terminators of
241 /// all terminators except the specified basic blocks to a 'ret' instruction,
242 /// then running the simplify-cfg pass. This has the effect of chopping up
243 /// the CFG really fast which can reduce large functions quickly.
245 class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
247 bool (*TestFn)(BugDriver &, Module *);
249 ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
250 : BD(bd), TestFn(testFn) {}
252 virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
253 std::vector<const BasicBlock*> &Kept) {
254 if (!Kept.empty() && TestBlocks(Kept))
256 if (!Prefix.empty() && TestBlocks(Prefix))
261 bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
265 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
266 // Clone the program to try hacking it apart...
267 Module *M = CloneModule(BD.getProgram());
269 // Convert list to set for fast lookup...
270 std::set<BasicBlock*> Blocks;
271 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
272 // Convert the basic block from the original module to the new module...
273 const Function *F = BBs[i]->getParent();
274 Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
275 assert(CMF && "Function not in module?!");
277 // Get the mapped basic block...
278 Function::iterator CBI = CMF->begin();
279 std::advance(CBI, std::distance(F->begin(),
280 Function::const_iterator(BBs[i])));
284 std::cout << "Checking for crash with only these blocks:";
285 unsigned NumPrint = Blocks.size();
286 if (NumPrint > 10) NumPrint = 10;
287 for (unsigned i = 0, e = NumPrint; i != e; ++i)
288 std::cout << " " << BBs[i]->getName();
289 if (NumPrint < Blocks.size())
290 std::cout << "... <" << Blocks.size() << " total>";
293 // Loop over and delete any hack up any blocks that are not listed...
294 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
295 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
296 if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
297 // Loop over all of the successors of this block, deleting any PHI nodes
298 // that might include it.
299 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
300 (*SI)->removePredecessor(BB);
302 if (BB->getTerminator()->getType() != Type::VoidTy)
303 BB->getTerminator()->replaceAllUsesWith(
304 Constant::getNullValue(BB->getTerminator()->getType()));
306 // Delete the old terminator instruction...
307 BB->getInstList().pop_back();
309 // Add a new return instruction of the appropriate type...
310 const Type *RetTy = BB->getParent()->getReturnType();
311 new ReturnInst(RetTy == Type::VoidTy ? 0 :
312 Constant::getNullValue(RetTy), BB);
315 // The CFG Simplifier pass may delete one of the basic blocks we are
316 // interested in. If it does we need to take the block out of the list. Make
317 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
318 // This won't work well if blocks are unnamed, but that is just the risk we
320 std::vector<std::pair<Function*, std::string> > BlockInfo;
322 for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
324 BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
326 // Now run the CFG simplify pass on the function...
328 Passes.add(createCFGSimplificationPass());
329 Passes.add(createVerifierPass());
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 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
340 SymbolTable &ST = BlockInfo[i].first->getSymbolTable();
341 SymbolTable::plane_iterator PI = ST.find(Type::LabelTy);
342 if (PI != ST.plane_end() && PI->second.count(BlockInfo[i].second))
343 BBs.push_back(cast<BasicBlock>(PI->second[BlockInfo[i].second]));
347 delete M; // It didn't crash, try something else.
351 /// DebugACrash - Given a predicate that determines whether a component crashes
352 /// on a program, try to destructively reduce the program while still keeping
353 /// the predicate true.
354 static bool DebugACrash(BugDriver &BD, bool (*TestFn)(BugDriver &, Module *)) {
355 // See if we can get away with nuking some of the global variable initializers
357 if (BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
358 // Now try to reduce the number of global variable initializers in the
359 // module to something small.
360 Module *M = CloneModule(BD.getProgram());
361 bool DeletedInit = false;
363 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
365 if (I->hasInitializer()) {
366 I->setInitializer(0);
367 I->setLinkage(GlobalValue::ExternalLinkage);
372 delete M; // No change made...
374 // See if the program still causes a crash...
375 std::cout << "\nChecking to see if we can delete global inits: ";
377 if (TestFn(BD, M)) { // Still crashes?
379 std::cout << "\n*** Able to remove all global initializers!\n";
380 } else { // No longer crashes?
381 std::cout << " - Removing all global inits hides problem!\n";
384 std::vector<GlobalVariable*> GVs;
386 for (Module::global_iterator I = BD.getProgram()->global_begin(),
387 E = BD.getProgram()->global_end(); I != E; ++I)
388 if (I->hasInitializer())
391 if (GVs.size() > 1 && !BugpointIsInterrupted) {
392 std::cout << "\n*** Attempting to reduce the number of global "
393 << "variables in the testcase\n";
395 unsigned OldSize = GVs.size();
396 ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs);
398 if (GVs.size() < OldSize)
399 BD.EmitProgressBytecode("reduced-global-variables");
405 // Now try to reduce the number of functions in the module to something small.
406 std::vector<Function*> Functions;
407 for (Module::iterator I = BD.getProgram()->begin(),
408 E = BD.getProgram()->end(); I != E; ++I)
409 if (!I->isExternal())
410 Functions.push_back(I);
412 if (Functions.size() > 1 && !BugpointIsInterrupted) {
413 std::cout << "\n*** Attempting to reduce the number of functions "
416 unsigned OldSize = Functions.size();
417 ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
419 if (Functions.size() < OldSize)
420 BD.EmitProgressBytecode("reduced-function");
423 // Attempt to delete entire basic blocks at a time to speed up
424 // convergence... this actually works by setting the terminator of the blocks
425 // to a return instruction then running simplifycfg, which can potentially
426 // shrinks the code dramatically quickly
428 if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
429 std::vector<const BasicBlock*> Blocks;
430 for (Module::const_iterator I = BD.getProgram()->begin(),
431 E = BD.getProgram()->end(); I != E; ++I)
432 for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
433 Blocks.push_back(FI);
434 ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
437 // FIXME: This should use the list reducer to converge faster by deleting
438 // larger chunks of instructions at a time!
439 unsigned Simplification = 2;
441 if (BugpointIsInterrupted) break;
443 std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
444 << "tions: Simplification Level #" << Simplification << '\n';
446 // Now that we have deleted the functions that are unnecessary for the
447 // program, try to remove instructions that are not necessary to cause the
448 // crash. To do this, we loop through all of the instructions in the
449 // remaining functions, deleting them (replacing any values produced with
450 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
451 // still triggers failure, keep deleting until we cannot trigger failure
454 unsigned InstructionsToSkipBeforeDeleting = 0;
457 // Loop over all of the (non-terminator) instructions remaining in the
458 // function, attempting to delete them.
459 unsigned CurInstructionNum = 0;
460 for (Module::const_iterator FI = BD.getProgram()->begin(),
461 E = BD.getProgram()->end(); FI != E; ++FI)
462 if (!FI->isExternal())
463 for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
465 for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
466 I != E; ++I, ++CurInstructionNum)
467 if (InstructionsToSkipBeforeDeleting) {
468 --InstructionsToSkipBeforeDeleting;
470 if (BugpointIsInterrupted) goto ExitLoops;
472 std::cout << "Checking instruction '" << I->getName() << "': ";
473 Module *M = BD.deleteInstructionFromProgram(I, Simplification);
475 // Find out if the pass still crashes on this pass...
477 // Yup, it does, we delete the old module, and continue trying
478 // to reduce the testcase...
480 InstructionsToSkipBeforeDeleting = CurInstructionNum;
481 goto TryAgain; // I wish I had a multi-level break here!
484 // This pass didn't crash without this instruction, try the next
489 if (InstructionsToSkipBeforeDeleting) {
490 InstructionsToSkipBeforeDeleting = 0;
494 } while (Simplification);
497 // Try to clean up the testcase by running funcresolve and globaldce...
498 if (!BugpointIsInterrupted) {
499 std::cout << "\n*** Attempting to perform final cleanups: ";
500 Module *M = CloneModule(BD.getProgram());
501 M = BD.performFinalCleanups(M, true);
503 // Find out if the pass still crashes on the cleaned up program...
505 BD.setNewProgram(M); // Yup, it does, keep the reduced version...
511 BD.EmitProgressBytecode("reduced-simplified");
516 static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
517 return BD.runPasses(M);
520 /// debugOptimizerCrash - This method is called when some pass crashes on input.
521 /// It attempts to prune down the testcase to something reasonable, and figure
522 /// out exactly which pass is crashing.
524 bool BugDriver::debugOptimizerCrash(const std::string &ID) {
525 std::cout << "\n*** Debugging optimizer crash!\n";
527 // Reduce the list of passes which causes the optimizer to crash...
528 unsigned OldSize = PassesToRun.size();
529 if (!BugpointIsInterrupted)
530 ReducePassList(*this).reduceList(PassesToRun);
532 std::cout << "\n*** Found crashing pass"
533 << (PassesToRun.size() == 1 ? ": " : "es: ")
534 << getPassesString(PassesToRun) << '\n';
536 EmitProgressBytecode(ID);
538 return DebugACrash(*this, TestForOptimizerCrash);
541 static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
544 BD.compileProgram(M);
547 } catch (ToolExecutionError &) {
548 std::cerr << "<crash>\n";
549 return true; // Tool is still crashing.
553 /// debugCodeGeneratorCrash - This method is called when the code generator
554 /// crashes on an input. It attempts to reduce the input as much as possible
555 /// while still causing the code generator to crash.
556 bool BugDriver::debugCodeGeneratorCrash() {
557 std::cerr << "*** Debugging code generator crash!\n";
559 return DebugACrash(*this, TestForCodeGenCrash);