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 "ListReducer.h"
16 #include "llvm/Constant.h"
17 #include "llvm/Instructions.h"
18 #include "llvm/Module.h"
19 #include "llvm/Pass.h"
20 #include "llvm/PassManager.h"
21 #include "llvm/SymbolTable.h"
22 #include "llvm/Type.h"
23 #include "llvm/Analysis/Verifier.h"
24 #include "llvm/Bytecode/Writer.h"
25 #include "llvm/Support/CFG.h"
26 #include "llvm/Support/ToolRunner.h"
27 #include "llvm/Transforms/Scalar.h"
28 #include "llvm/Transforms/Utils/Cloning.h"
29 #include "llvm/Support/FileUtilities.h"
35 class ReducePassList : public ListReducer<const PassInfo*> {
38 ReducePassList(BugDriver &bd) : BD(bd) {}
40 // doTest - Return true iff running the "removed" passes succeeds, and
41 // running the "Kept" passes fail when run on the output of the "removed"
42 // passes. If we return true, we update the current module of bugpoint.
44 virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
45 std::vector<const PassInfo*> &Kept);
49 ReducePassList::TestResult
50 ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
51 std::vector<const PassInfo*> &Suffix) {
52 sys::Path PrefixOutput;
53 Module *OrigProgram = 0;
54 if (!Prefix.empty()) {
55 std::cout << "Checking to see if these passes crash: "
56 << getPassesString(Prefix) << ": ";
57 std::string PfxOutput;
58 if (BD.runPasses(Prefix, PfxOutput))
61 PrefixOutput.set(PfxOutput);
62 OrigProgram = BD.Program;
64 BD.Program = ParseInputFile(PrefixOutput.toString());
65 if (BD.Program == 0) {
66 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
67 << PrefixOutput << "'!\n";
70 PrefixOutput.eraseFromDisk();
73 std::cout << "Checking to see if these passes crash: "
74 << getPassesString(Suffix) << ": ";
76 if (BD.runPasses(Suffix)) {
77 delete OrigProgram; // The suffix crashes alone...
81 // Nothing failed, restore state...
84 BD.Program = OrigProgram;
90 class ReduceCrashingFunctions : public ListReducer<Function*> {
92 bool (*TestFn)(BugDriver &, Module *);
94 ReduceCrashingFunctions(BugDriver &bd,
95 bool (*testFn)(BugDriver &, Module *))
96 : BD(bd), TestFn(testFn) {}
98 virtual TestResult doTest(std::vector<Function*> &Prefix,
99 std::vector<Function*> &Kept) {
100 if (!Kept.empty() && TestFuncs(Kept))
102 if (!Prefix.empty() && TestFuncs(Prefix))
107 bool TestFuncs(std::vector<Function*> &Prefix);
111 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
112 // Clone the program to try hacking it apart...
113 Module *M = CloneModule(BD.getProgram());
115 // Convert list to set for fast lookup...
116 std::set<Function*> Functions;
117 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
118 Function *CMF = M->getFunction(Funcs[i]->getName(),
119 Funcs[i]->getFunctionType());
120 assert(CMF && "Function not in module?!");
121 Functions.insert(CMF);
124 std::cout << "Checking for crash with only these functions: ";
125 PrintFunctionList(Funcs);
128 // Loop over and delete any functions which we aren't supposed to be playing
130 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
131 if (!I->isExternal() && !Functions.count(I))
132 DeleteFunctionBody(I);
134 // Try running the hacked up program...
136 BD.setNewProgram(M); // It crashed, keep the trimmed version...
138 // Make sure to use function pointers that point into the now-current
140 Funcs.assign(Functions.begin(), Functions.end());
149 /// ReduceCrashingBlocks reducer - This works by setting the terminators of
150 /// all terminators except the specified basic blocks to a 'ret' instruction,
151 /// then running the simplify-cfg pass. This has the effect of chopping up
152 /// the CFG really fast which can reduce large functions quickly.
154 class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
156 bool (*TestFn)(BugDriver &, Module *);
158 ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
159 : BD(bd), TestFn(testFn) {}
161 virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
162 std::vector<const BasicBlock*> &Kept) {
163 if (!Kept.empty() && TestBlocks(Kept))
165 if (!Prefix.empty() && TestBlocks(Prefix))
170 bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
174 bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
175 // Clone the program to try hacking it apart...
176 Module *M = CloneModule(BD.getProgram());
178 // Convert list to set for fast lookup...
179 std::set<BasicBlock*> Blocks;
180 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
181 // Convert the basic block from the original module to the new module...
182 const Function *F = BBs[i]->getParent();
183 Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
184 assert(CMF && "Function not in module?!");
186 // Get the mapped basic block...
187 Function::iterator CBI = CMF->begin();
188 std::advance(CBI, std::distance(F->begin(),
189 Function::const_iterator(BBs[i])));
193 std::cout << "Checking for crash with only these blocks:";
194 unsigned NumPrint = Blocks.size();
195 if (NumPrint > 10) NumPrint = 10;
196 for (unsigned i = 0, e = NumPrint; i != e; ++i)
197 std::cout << " " << BBs[i]->getName();
198 if (NumPrint < Blocks.size())
199 std::cout << "... <" << Blocks.size() << " total>";
202 // Loop over and delete any hack up any blocks that are not listed...
203 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
204 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
205 if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
206 // Loop over all of the successors of this block, deleting any PHI nodes
207 // that might include it.
208 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
209 (*SI)->removePredecessor(BB);
211 if (BB->getTerminator()->getType() != Type::VoidTy)
212 BB->getTerminator()->replaceAllUsesWith(
213 Constant::getNullValue(BB->getTerminator()->getType()));
215 // Delete the old terminator instruction...
216 BB->getInstList().pop_back();
218 // Add a new return instruction of the appropriate type...
219 const Type *RetTy = BB->getParent()->getReturnType();
220 new ReturnInst(RetTy == Type::VoidTy ? 0 :
221 Constant::getNullValue(RetTy), BB);
224 // The CFG Simplifier pass may delete one of the basic blocks we are
225 // interested in. If it does we need to take the block out of the list. Make
226 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
227 // This won't work well if blocks are unnamed, but that is just the risk we
229 std::vector<std::pair<Function*, std::string> > BlockInfo;
231 for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
233 BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
235 // Now run the CFG simplify pass on the function...
237 Passes.add(createCFGSimplificationPass());
238 Passes.add(createVerifierPass());
241 // Try running on the hacked up program...
243 BD.setNewProgram(M); // It crashed, keep the trimmed version...
245 // Make sure to use basic block pointers that point into the now-current
246 // module, and that they don't include any deleted blocks.
248 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
249 SymbolTable &ST = BlockInfo[i].first->getSymbolTable();
250 SymbolTable::plane_iterator PI = ST.find(Type::LabelTy);
251 if (PI != ST.plane_end() && PI->second.count(BlockInfo[i].second))
252 BBs.push_back(cast<BasicBlock>(PI->second[BlockInfo[i].second]));
256 delete M; // It didn't crash, try something else.
260 /// DebugACrash - Given a predicate that determines whether a component crashes
261 /// on a program, try to destructively reduce the program while still keeping
262 /// the predicate true.
263 static bool DebugACrash(BugDriver &BD, bool (*TestFn)(BugDriver &, Module *)) {
264 // See if we can get away with nuking all of the global variable initializers
266 if (BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
267 Module *M = CloneModule(BD.getProgram());
268 bool DeletedInit = false;
269 for (Module::global_iterator I = M->global_begin(), E = M->global_end(); I != E; ++I)
270 if (I->hasInitializer()) {
271 I->setInitializer(0);
272 I->setLinkage(GlobalValue::ExternalLinkage);
277 delete M; // No change made...
279 // See if the program still causes a crash...
280 std::cout << "\nChecking to see if we can delete global inits: ";
281 if (TestFn(BD, M)) { // Still crashes?
283 std::cout << "\n*** Able to remove all global initializers!\n";
284 } else { // No longer crashes?
285 std::cout << " - Removing all global inits hides problem!\n";
291 // Now try to reduce the number of functions in the module to something small.
292 std::vector<Function*> Functions;
293 for (Module::iterator I = BD.getProgram()->begin(),
294 E = BD.getProgram()->end(); I != E; ++I)
295 if (!I->isExternal())
296 Functions.push_back(I);
298 if (Functions.size() > 1 && !BugpointIsInterrupted) {
299 std::cout << "\n*** Attempting to reduce the number of functions "
302 unsigned OldSize = Functions.size();
303 ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
305 if (Functions.size() < OldSize)
306 BD.EmitProgressBytecode("reduced-function");
309 // Attempt to delete entire basic blocks at a time to speed up
310 // convergence... this actually works by setting the terminator of the blocks
311 // to a return instruction then running simplifycfg, which can potentially
312 // shrinks the code dramatically quickly
314 if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
315 std::vector<const BasicBlock*> Blocks;
316 for (Module::const_iterator I = BD.getProgram()->begin(),
317 E = BD.getProgram()->end(); I != E; ++I)
318 for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
319 Blocks.push_back(FI);
320 ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
323 // FIXME: This should use the list reducer to converge faster by deleting
324 // larger chunks of instructions at a time!
325 unsigned Simplification = 2;
327 if (BugpointIsInterrupted) break;
329 std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
330 << "tions: Simplification Level #" << Simplification << '\n';
332 // Now that we have deleted the functions that are unnecessary for the
333 // program, try to remove instructions that are not necessary to cause the
334 // crash. To do this, we loop through all of the instructions in the
335 // remaining functions, deleting them (replacing any values produced with
336 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
337 // still triggers failure, keep deleting until we cannot trigger failure
340 unsigned InstructionsToSkipBeforeDeleting = 0;
343 // Loop over all of the (non-terminator) instructions remaining in the
344 // function, attempting to delete them.
345 unsigned CurInstructionNum = 0;
346 for (Module::const_iterator FI = BD.getProgram()->begin(),
347 E = BD.getProgram()->end(); FI != E; ++FI)
348 if (!FI->isExternal())
349 for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
351 for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
352 I != E; ++I, ++CurInstructionNum)
353 if (InstructionsToSkipBeforeDeleting) {
354 --InstructionsToSkipBeforeDeleting;
356 if (BugpointIsInterrupted) goto ExitLoops;
358 std::cout << "Checking instruction '" << I->getName() << "': ";
359 Module *M = BD.deleteInstructionFromProgram(I, Simplification);
361 // Find out if the pass still crashes on this pass...
363 // Yup, it does, we delete the old module, and continue trying
364 // to reduce the testcase...
366 InstructionsToSkipBeforeDeleting = CurInstructionNum;
367 goto TryAgain; // I wish I had a multi-level break here!
370 // This pass didn't crash without this instruction, try the next
375 if (InstructionsToSkipBeforeDeleting) {
376 InstructionsToSkipBeforeDeleting = 0;
380 } while (Simplification);
383 // Try to clean up the testcase by running funcresolve and globaldce...
384 if (!BugpointIsInterrupted) {
385 std::cout << "\n*** Attempting to perform final cleanups: ";
386 Module *M = CloneModule(BD.getProgram());
387 M = BD.performFinalCleanups(M, true);
389 // Find out if the pass still crashes on the cleaned up program...
391 BD.setNewProgram(M); // Yup, it does, keep the reduced version...
397 BD.EmitProgressBytecode("reduced-simplified");
402 static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
403 return BD.runPasses(M);
406 /// debugOptimizerCrash - This method is called when some pass crashes on input.
407 /// It attempts to prune down the testcase to something reasonable, and figure
408 /// out exactly which pass is crashing.
410 bool BugDriver::debugOptimizerCrash() {
411 std::cout << "\n*** Debugging optimizer crash!\n";
413 // Reduce the list of passes which causes the optimizer to crash...
414 unsigned OldSize = PassesToRun.size();
415 if (!BugpointIsInterrupted)
416 ReducePassList(*this).reduceList(PassesToRun);
418 std::cout << "\n*** Found crashing pass"
419 << (PassesToRun.size() == 1 ? ": " : "es: ")
420 << getPassesString(PassesToRun) << '\n';
422 EmitProgressBytecode("passinput");
424 return DebugACrash(*this, TestForOptimizerCrash);
427 static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
430 BD.compileProgram(M);
433 } catch (ToolExecutionError &) {
434 std::cerr << "<crash>\n";
435 return true; // Tool is still crashing.
439 /// debugCodeGeneratorCrash - This method is called when the code generator
440 /// crashes on an input. It attempts to reduce the input as much as possible
441 /// while still causing the code generator to crash.
442 bool BugDriver::debugCodeGeneratorCrash() {
443 std::cerr << "*** Debugging code generator crash!\n";
445 return DebugACrash(*this, TestForCodeGenCrash);