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/iTerminators.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/Transforms/Scalar.h"
27 #include "llvm/Transforms/Utils/Cloning.h"
28 #include "Support/FileUtilities.h"
32 class DebugCrashes : public ListReducer<const PassInfo*> {
35 DebugCrashes(BugDriver &bd) : BD(bd) {}
37 // doTest - Return true iff running the "removed" passes succeeds, and running
38 // the "Kept" passes fail when run on the output of the "removed" passes. If
39 // we return true, we update the current module of bugpoint.
41 virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
42 std::vector<const PassInfo*> &Kept);
45 DebugCrashes::TestResult
46 DebugCrashes::doTest(std::vector<const PassInfo*> &Prefix,
47 std::vector<const PassInfo*> &Suffix) {
48 std::string PrefixOutput;
49 Module *OrigProgram = 0;
50 if (!Prefix.empty()) {
51 std::cout << "Checking to see if these passes crash: "
52 << getPassesString(Prefix) << ": ";
53 if (BD.runPasses(Prefix, PrefixOutput))
56 OrigProgram = BD.Program;
58 BD.Program = BD.ParseInputFile(PrefixOutput);
59 if (BD.Program == 0) {
60 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
61 << PrefixOutput << "'!\n";
64 removeFile(PrefixOutput);
67 std::cout << "Checking to see if these passes crash: "
68 << getPassesString(Suffix) << ": ";
70 if (BD.runPasses(Suffix)) {
71 delete OrigProgram; // The suffix crashes alone...
75 // Nothing failed, restore state...
78 BD.Program = OrigProgram;
83 class ReduceCrashingFunctions : public ListReducer<Function*> {
86 ReduceCrashingFunctions(BugDriver &bd) : BD(bd) {}
88 virtual TestResult doTest(std::vector<Function*> &Prefix,
89 std::vector<Function*> &Kept) {
90 if (!Kept.empty() && TestFuncs(Kept))
92 if (!Prefix.empty() && TestFuncs(Prefix))
97 bool TestFuncs(std::vector<Function*> &Prefix);
100 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
101 // Clone the program to try hacking it apart...
102 Module *M = CloneModule(BD.Program);
104 // Convert list to set for fast lookup...
105 std::set<Function*> Functions;
106 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
107 Function *CMF = M->getFunction(Funcs[i]->getName(),
108 Funcs[i]->getFunctionType());
109 assert(CMF && "Function not in module?!");
110 Functions.insert(CMF);
113 std::cout << "Checking for crash with only these functions:";
114 unsigned NumPrint = Funcs.size();
115 if (NumPrint > 10) NumPrint = 10;
116 for (unsigned i = 0; i != NumPrint; ++i)
117 std::cout << " " << Funcs[i]->getName();
118 if (NumPrint < Funcs.size())
119 std::cout << "... <" << Funcs.size() << " total>";
122 // Loop over and delete any functions which we aren't supposed to be playing
124 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
125 if (!I->isExternal() && !Functions.count(I))
126 DeleteFunctionBody(I);
128 // Try running the hacked up program...
129 std::swap(BD.Program, M);
130 if (BD.runPasses(BD.PassesToRun)) {
131 delete M; // It crashed, keep the trimmed version...
133 // Make sure to use function pointers that point into the now-current
135 Funcs.assign(Functions.begin(), Functions.end());
138 delete BD.Program; // It didn't crash, revert...
144 /// ReduceCrashingBlocks reducer - This works by setting the terminators of all
145 /// terminators except the specified basic blocks to a 'ret' instruction, then
146 /// running the simplify-cfg pass. This has the effect of chopping up the CFG
147 /// really fast which can reduce large functions quickly.
149 class ReduceCrashingBlocks : public ListReducer<BasicBlock*> {
152 ReduceCrashingBlocks(BugDriver &bd) : BD(bd) {}
154 virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
155 std::vector<BasicBlock*> &Kept) {
156 if (!Kept.empty() && TestBlocks(Kept))
158 if (!Prefix.empty() && TestBlocks(Prefix))
163 bool TestBlocks(std::vector<BasicBlock*> &Prefix);
166 bool ReduceCrashingBlocks::TestBlocks(std::vector<BasicBlock*> &BBs) {
167 // Clone the program to try hacking it apart...
168 Module *M = CloneModule(BD.Program);
170 // Convert list to set for fast lookup...
171 std::set<BasicBlock*> Blocks;
172 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
173 // Convert the basic block from the original module to the new module...
174 Function *F = BBs[i]->getParent();
175 Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
176 assert(CMF && "Function not in module?!");
178 // Get the mapped basic block...
179 Function::iterator CBI = CMF->begin();
180 std::advance(CBI, std::distance(F->begin(), Function::iterator(BBs[i])));
184 std::cout << "Checking for crash with only these blocks:";
185 unsigned NumPrint = Blocks.size();
186 if (NumPrint > 10) NumPrint = 10;
187 for (unsigned i = 0, e = NumPrint; i != e; ++i)
188 std::cout << " " << BBs[i]->getName();
189 if (NumPrint < Blocks.size())
190 std::cout << "... <" << Blocks.size() << " total>";
193 // Loop over and delete any hack up any blocks that are not listed...
194 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
195 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
196 if (!Blocks.count(BB) && !isa<ReturnInst>(BB->getTerminator())) {
197 // Loop over all of the successors of this block, deleting any PHI nodes
198 // that might include it.
199 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
200 (*SI)->removePredecessor(BB);
202 // Delete the old terminator instruction...
203 BB->getInstList().pop_back();
205 // Add a new return instruction of the appropriate type...
206 const Type *RetTy = BB->getParent()->getReturnType();
207 ReturnInst *RI = new ReturnInst(RetTy == Type::VoidTy ? 0 :
208 Constant::getNullValue(RetTy));
209 BB->getInstList().push_back(RI);
212 // The CFG Simplifier pass may delete one of the basic blocks we are
213 // interested in. If it does we need to take the block out of the list. Make
214 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
215 // This won't work well if blocks are unnamed, but that is just the risk we
217 std::vector<std::pair<Function*, std::string> > BlockInfo;
219 for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
221 BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
223 // Now run the CFG simplify pass on the function...
225 Passes.add(createCFGSimplificationPass());
226 Passes.add(createVerifierPass());
229 // Try running on the hacked up program...
230 std::swap(BD.Program, M);
231 if (BD.runPasses(BD.PassesToRun)) {
232 delete M; // It crashed, keep the trimmed version...
234 // Make sure to use basic block pointers that point into the now-current
235 // module, and that they don't include any deleted blocks.
237 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
238 SymbolTable &ST = BlockInfo[i].first->getSymbolTable();
239 SymbolTable::iterator I = ST.find(Type::LabelTy);
240 if (I != ST.end() && I->second.count(BlockInfo[i].second))
241 BBs.push_back(cast<BasicBlock>(I->second[BlockInfo[i].second]));
245 delete BD.Program; // It didn't crash, revert...
250 /// debugCrash - This method is called when some pass crashes on input. It
251 /// attempts to prune down the testcase to something reasonable, and figure
252 /// out exactly which pass is crashing.
254 bool BugDriver::debugCrash() {
255 bool AnyReduction = false;
256 std::cout << "\n*** Debugging optimizer crash!\n";
258 // Reduce the list of passes which causes the optimizer to crash...
259 unsigned OldSize = PassesToRun.size();
260 DebugCrashes(*this).reduceList(PassesToRun);
262 std::cout << "\n*** Found crashing pass"
263 << (PassesToRun.size() == 1 ? ": " : "es: ")
264 << getPassesString(PassesToRun) << "\n";
266 EmitProgressBytecode("passinput");
268 // See if we can get away with nuking all of the global variable initializers
270 if (Program->gbegin() != Program->gend()) {
271 Module *M = CloneModule(Program);
272 bool DeletedInit = false;
273 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
274 if (I->hasInitializer()) {
275 I->setInitializer(0);
276 I->setLinkage(GlobalValue::ExternalLinkage);
281 delete M; // No change made...
283 // See if the program still causes a crash...
284 std::cout << "\nChecking to see if we can delete global inits: ";
285 std::swap(Program, M);
286 if (runPasses(PassesToRun)) { // Still crashes?
289 std::cout << "\n*** Able to remove all global initializers!\n";
290 } else { // No longer crashes?
291 delete Program; // Restore program.
293 std::cout << " - Removing all global inits hides problem!\n";
298 // Now try to reduce the number of functions in the module to something small.
299 std::vector<Function*> Functions;
300 for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
301 if (!I->isExternal())
302 Functions.push_back(I);
304 if (Functions.size() > 1) {
305 std::cout << "\n*** Attempting to reduce the number of functions "
308 OldSize = Functions.size();
309 ReduceCrashingFunctions(*this).reduceList(Functions);
311 if (Functions.size() < OldSize) {
312 EmitProgressBytecode("reduced-function");
317 // Attempt to delete entire basic blocks at a time to speed up
318 // convergence... this actually works by setting the terminator of the blocks
319 // to a return instruction then running simplifycfg, which can potentially
320 // shrinks the code dramatically quickly
322 if (!DisableSimplifyCFG) {
323 std::vector<BasicBlock*> Blocks;
324 for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
325 for (Function::iterator FI = I->begin(), E = I->end(); FI != E; ++FI)
326 Blocks.push_back(FI);
327 ReduceCrashingBlocks(*this).reduceList(Blocks);
330 // FIXME: This should use the list reducer to converge faster by deleting
331 // larger chunks of instructions at a time!
332 unsigned Simplification = 4;
335 std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
336 << "tions: Simplification Level #" << Simplification << "\n";
338 // Now that we have deleted the functions that are unnecessary for the
339 // program, try to remove instructions that are not necessary to cause the
340 // crash. To do this, we loop through all of the instructions in the
341 // remaining functions, deleting them (replacing any values produced with
342 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
343 // still triggers failure, keep deleting until we cannot trigger failure
348 // Loop over all of the (non-terminator) instructions remaining in the
349 // function, attempting to delete them.
350 for (Module::iterator FI = Program->begin(), E = Program->end();
352 if (!FI->isExternal()) {
353 for (Function::iterator BI = FI->begin(), E = FI->end(); BI != E; ++BI)
354 for (BasicBlock::iterator I = BI->begin(), E = --BI->end();
356 Module *M = deleteInstructionFromProgram(I, Simplification);
358 // Make the function the current program...
359 std::swap(Program, M);
361 // Find out if the pass still crashes on this pass...
362 std::cout << "Checking instruction '" << I->getName() << "': ";
363 if (runPasses(PassesToRun)) {
364 // Yup, it does, we delete the old module, and continue trying to
365 // reduce the testcase...
368 goto TryAgain; // I wish I had a multi-level break here!
371 // This pass didn't crash without this instruction, try the next
377 } while (Simplification);
379 // Try to clean up the testcase by running funcresolve and globaldce...
380 std::cout << "\n*** Attempting to perform final cleanups: ";
381 Module *M = performFinalCleanups();
382 std::swap(Program, M);
384 // Find out if the pass still crashes on the cleaned up program...
385 if (runPasses(PassesToRun)) {
386 // Yup, it does, keep the reduced version...
390 delete Program; // Otherwise, restore the original module...
395 EmitProgressBytecode("reduced-simplified");