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"
34 class DebugCrashes : public ListReducer<const PassInfo*> {
37 DebugCrashes(BugDriver &bd) : BD(bd) {}
39 // doTest - Return true iff running the "removed" passes succeeds, and
40 // running the "Kept" passes fail when run on the output of the "removed"
41 // passes. If we return true, we update the current module of bugpoint.
43 virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
44 std::vector<const PassInfo*> &Kept);
48 DebugCrashes::TestResult
49 DebugCrashes::doTest(std::vector<const PassInfo*> &Prefix,
50 std::vector<const PassInfo*> &Suffix) {
51 std::string PrefixOutput;
52 Module *OrigProgram = 0;
53 if (!Prefix.empty()) {
54 std::cout << "Checking to see if these passes crash: "
55 << getPassesString(Prefix) << ": ";
56 if (BD.runPasses(Prefix, PrefixOutput))
59 OrigProgram = BD.Program;
61 BD.Program = BD.ParseInputFile(PrefixOutput);
62 if (BD.Program == 0) {
63 std::cerr << BD.getToolName() << ": Error reading bytecode file '"
64 << PrefixOutput << "'!\n";
67 removeFile(PrefixOutput);
70 std::cout << "Checking to see if these passes crash: "
71 << getPassesString(Suffix) << ": ";
73 if (BD.runPasses(Suffix)) {
74 delete OrigProgram; // The suffix crashes alone...
78 // Nothing failed, restore state...
81 BD.Program = OrigProgram;
87 class ReduceCrashingFunctions : public ListReducer<Function*> {
90 ReduceCrashingFunctions(BugDriver &bd) : BD(bd) {}
92 virtual TestResult doTest(std::vector<Function*> &Prefix,
93 std::vector<Function*> &Kept) {
94 if (!Kept.empty() && TestFuncs(Kept))
96 if (!Prefix.empty() && TestFuncs(Prefix))
101 bool TestFuncs(std::vector<Function*> &Prefix);
105 bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
106 // Clone the program to try hacking it apart...
107 Module *M = CloneModule(BD.Program);
109 // Convert list to set for fast lookup...
110 std::set<Function*> Functions;
111 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
112 Function *CMF = M->getFunction(Funcs[i]->getName(),
113 Funcs[i]->getFunctionType());
114 assert(CMF && "Function not in module?!");
115 Functions.insert(CMF);
118 std::cout << "Checking for crash with only these functions:";
119 unsigned NumPrint = Funcs.size();
120 if (NumPrint > 10) NumPrint = 10;
121 for (unsigned i = 0; i != NumPrint; ++i)
122 std::cout << " " << Funcs[i]->getName();
123 if (NumPrint < Funcs.size())
124 std::cout << "... <" << Funcs.size() << " total>";
127 // Loop over and delete any functions which we aren't supposed to be playing
129 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
130 if (!I->isExternal() && !Functions.count(I))
131 DeleteFunctionBody(I);
133 // Try running the hacked up program...
134 std::swap(BD.Program, M);
135 if (BD.runPasses(BD.PassesToRun)) {
136 delete 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());
143 delete BD.Program; // It didn't crash, revert...
150 /// ReduceCrashingBlocks reducer - This works by setting the terminators of
151 /// all terminators except the specified basic blocks to a 'ret' instruction,
152 /// then running the simplify-cfg pass. This has the effect of chopping up
153 /// the CFG really fast which can reduce large functions quickly.
155 class ReduceCrashingBlocks : public ListReducer<BasicBlock*> {
158 ReduceCrashingBlocks(BugDriver &bd) : BD(bd) {}
160 virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
161 std::vector<BasicBlock*> &Kept) {
162 if (!Kept.empty() && TestBlocks(Kept))
164 if (!Prefix.empty() && TestBlocks(Prefix))
169 bool TestBlocks(std::vector<BasicBlock*> &Prefix);
173 bool ReduceCrashingBlocks::TestBlocks(std::vector<BasicBlock*> &BBs) {
174 // Clone the program to try hacking it apart...
175 Module *M = CloneModule(BD.Program);
177 // Convert list to set for fast lookup...
178 std::set<BasicBlock*> Blocks;
179 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
180 // Convert the basic block from the original module to the new module...
181 Function *F = BBs[i]->getParent();
182 Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
183 assert(CMF && "Function not in module?!");
185 // Get the mapped basic block...
186 Function::iterator CBI = CMF->begin();
187 std::advance(CBI, std::distance(F->begin(), Function::iterator(BBs[i])));
191 std::cout << "Checking for crash with only these blocks:";
192 unsigned NumPrint = Blocks.size();
193 if (NumPrint > 10) NumPrint = 10;
194 for (unsigned i = 0, e = NumPrint; i != e; ++i)
195 std::cout << " " << BBs[i]->getName();
196 if (NumPrint < Blocks.size())
197 std::cout << "... <" << Blocks.size() << " total>";
200 // Loop over and delete any hack up any blocks that are not listed...
201 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
202 for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
203 if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
204 // Loop over all of the successors of this block, deleting any PHI nodes
205 // that might include it.
206 for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
207 (*SI)->removePredecessor(BB);
209 if (BB->getTerminator()->getType() != Type::VoidTy)
210 BB->getTerminator()->replaceAllUsesWith(
211 Constant::getNullValue(BB->getTerminator()->getType()));
213 // Delete the old terminator instruction...
214 BB->getInstList().pop_back();
216 // Add a new return instruction of the appropriate type...
217 const Type *RetTy = BB->getParent()->getReturnType();
218 new ReturnInst(RetTy == Type::VoidTy ? 0 :
219 Constant::getNullValue(RetTy), BB);
222 // The CFG Simplifier pass may delete one of the basic blocks we are
223 // interested in. If it does we need to take the block out of the list. Make
224 // a "persistent mapping" by turning basic blocks into <function, name> pairs.
225 // This won't work well if blocks are unnamed, but that is just the risk we
227 std::vector<std::pair<Function*, std::string> > BlockInfo;
229 for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
231 BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
233 // Now run the CFG simplify pass on the function...
235 Passes.add(createCFGSimplificationPass());
236 Passes.add(createVerifierPass());
239 // Try running on the hacked up program...
240 std::swap(BD.Program, M);
241 if (BD.runPasses(BD.PassesToRun)) {
242 delete M; // It crashed, keep the trimmed version...
244 // Make sure to use basic block pointers that point into the now-current
245 // module, and that they don't include any deleted blocks.
247 for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
248 SymbolTable &ST = BlockInfo[i].first->getSymbolTable();
249 SymbolTable::iterator I = ST.find(Type::LabelTy);
250 if (I != ST.end() && I->second.count(BlockInfo[i].second))
251 BBs.push_back(cast<BasicBlock>(I->second[BlockInfo[i].second]));
255 delete BD.Program; // It didn't crash, revert...
260 /// debugCrash - This method is called when some pass crashes on input. It
261 /// attempts to prune down the testcase to something reasonable, and figure
262 /// out exactly which pass is crashing.
264 bool BugDriver::debugCrash() {
265 bool AnyReduction = false;
266 std::cout << "\n*** Debugging optimizer crash!\n";
268 // Reduce the list of passes which causes the optimizer to crash...
269 unsigned OldSize = PassesToRun.size();
270 DebugCrashes(*this).reduceList(PassesToRun);
272 std::cout << "\n*** Found crashing pass"
273 << (PassesToRun.size() == 1 ? ": " : "es: ")
274 << getPassesString(PassesToRun) << "\n";
276 EmitProgressBytecode("passinput");
278 // See if we can get away with nuking all of the global variable initializers
280 if (Program->gbegin() != Program->gend()) {
281 Module *M = CloneModule(Program);
282 bool DeletedInit = false;
283 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
284 if (I->hasInitializer()) {
285 I->setInitializer(0);
286 I->setLinkage(GlobalValue::ExternalLinkage);
291 delete M; // No change made...
293 // See if the program still causes a crash...
294 std::cout << "\nChecking to see if we can delete global inits: ";
295 std::swap(Program, M);
296 if (runPasses(PassesToRun)) { // Still crashes?
299 std::cout << "\n*** Able to remove all global initializers!\n";
300 } else { // No longer crashes?
301 delete Program; // Restore program.
303 std::cout << " - Removing all global inits hides problem!\n";
308 // Now try to reduce the number of functions in the module to something small.
309 std::vector<Function*> Functions;
310 for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
311 if (!I->isExternal())
312 Functions.push_back(I);
314 if (Functions.size() > 1) {
315 std::cout << "\n*** Attempting to reduce the number of functions "
318 OldSize = Functions.size();
319 ReduceCrashingFunctions(*this).reduceList(Functions);
321 if (Functions.size() < OldSize) {
322 EmitProgressBytecode("reduced-function");
327 // Attempt to delete entire basic blocks at a time to speed up
328 // convergence... this actually works by setting the terminator of the blocks
329 // to a return instruction then running simplifycfg, which can potentially
330 // shrinks the code dramatically quickly
332 if (!DisableSimplifyCFG) {
333 std::vector<BasicBlock*> Blocks;
334 for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
335 for (Function::iterator FI = I->begin(), E = I->end(); FI != E; ++FI)
336 Blocks.push_back(FI);
337 ReduceCrashingBlocks(*this).reduceList(Blocks);
340 // FIXME: This should use the list reducer to converge faster by deleting
341 // larger chunks of instructions at a time!
342 unsigned Simplification = 4;
345 std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
346 << "tions: Simplification Level #" << Simplification << "\n";
348 // Now that we have deleted the functions that are unnecessary for the
349 // program, try to remove instructions that are not necessary to cause the
350 // crash. To do this, we loop through all of the instructions in the
351 // remaining functions, deleting them (replacing any values produced with
352 // nulls), and then running ADCE and SimplifyCFG. If the transformed input
353 // still triggers failure, keep deleting until we cannot trigger failure
358 // Loop over all of the (non-terminator) instructions remaining in the
359 // function, attempting to delete them.
360 for (Module::iterator FI = Program->begin(), E = Program->end();
362 if (!FI->isExternal()) {
363 for (Function::iterator BI = FI->begin(), E = FI->end(); BI != E; ++BI)
364 for (BasicBlock::iterator I = BI->begin(), E = --BI->end();
366 Module *M = deleteInstructionFromProgram(I, Simplification);
368 // Make the function the current program...
369 std::swap(Program, M);
371 // Find out if the pass still crashes on this pass...
372 std::cout << "Checking instruction '" << I->getName() << "': ";
373 if (runPasses(PassesToRun)) {
374 // Yup, it does, we delete the old module, and continue trying to
375 // reduce the testcase...
378 goto TryAgain; // I wish I had a multi-level break here!
381 // This pass didn't crash without this instruction, try the next
387 } while (Simplification);
389 // Try to clean up the testcase by running funcresolve and globaldce...
390 std::cout << "\n*** Attempting to perform final cleanups: ";
391 Module *M = CloneModule(Program);
392 M = performFinalCleanups(M, true);
393 std::swap(Program, M);
395 // Find out if the pass still crashes on the cleaned up program...
396 if (runPasses(PassesToRun)) {
397 // Yup, it does, keep the reduced version...
401 delete Program; // Otherwise, restore the original module...
406 EmitProgressBytecode("reduced-simplified");