1 //===- Miscompilation.cpp - Debug program miscompilations -----------------===//
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 implements optimizer and code generation miscompilation debugging
13 //===----------------------------------------------------------------------===//
15 #include "BugDriver.h"
16 #include "ListReducer.h"
17 #include "ToolRunner.h"
18 #include "llvm/Config/config.h" // for HAVE_LINK_R
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DerivedTypes.h"
21 #include "llvm/IR/Instructions.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/IR/Verifier.h"
24 #include "llvm/Linker.h"
25 #include "llvm/Pass.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/FileUtilities.h"
28 #include "llvm/Transforms/Utils/Cloning.h"
32 extern cl::opt<std::string> OutputPrefix;
33 extern cl::list<std::string> InputArgv;
37 static llvm::cl::opt<bool>
38 DisableLoopExtraction("disable-loop-extraction",
39 cl::desc("Don't extract loops when searching for miscompilations"),
41 static llvm::cl::opt<bool>
42 DisableBlockExtraction("disable-block-extraction",
43 cl::desc("Don't extract blocks when searching for miscompilations"),
46 class ReduceMiscompilingPasses : public ListReducer<std::string> {
49 ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {}
51 virtual TestResult doTest(std::vector<std::string> &Prefix,
52 std::vector<std::string> &Suffix,
57 /// TestResult - After passes have been split into a test group and a control
58 /// group, see if they still break the program.
60 ReduceMiscompilingPasses::TestResult
61 ReduceMiscompilingPasses::doTest(std::vector<std::string> &Prefix,
62 std::vector<std::string> &Suffix,
64 // First, run the program with just the Suffix passes. If it is still broken
65 // with JUST the kept passes, discard the prefix passes.
66 outs() << "Checking to see if '" << getPassesString(Suffix)
67 << "' compiles correctly: ";
69 std::string BitcodeResult;
70 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/,
72 errs() << " Error running this sequence of passes"
73 << " on the input program!\n";
74 BD.setPassesToRun(Suffix);
75 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false);
76 exit(BD.debugOptimizerCrash());
79 // Check to see if the finished program matches the reference output...
80 bool Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "",
81 true /*delete bitcode*/, &Error);
87 errs() << BD.getToolName() << ": I'm confused: the test fails when "
88 << "no passes are run, nondeterministic program?\n";
91 return KeepSuffix; // Miscompilation detected!
93 outs() << " yup.\n"; // No miscompilation!
95 if (Prefix.empty()) return NoFailure;
97 // Next, see if the program is broken if we run the "prefix" passes first,
98 // then separately run the "kept" passes.
99 outs() << "Checking to see if '" << getPassesString(Prefix)
100 << "' compiles correctly: ";
102 // If it is not broken with the kept passes, it's possible that the prefix
103 // passes must be run before the kept passes to break it. If the program
104 // WORKS after the prefix passes, but then fails if running the prefix AND
105 // kept passes, we can update our bitcode file to include the result of the
106 // prefix passes, then discard the prefix passes.
108 if (BD.runPasses(BD.getProgram(), Prefix, BitcodeResult, false/*delete*/,
110 errs() << " Error running this sequence of passes"
111 << " on the input program!\n";
112 BD.setPassesToRun(Prefix);
113 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false);
114 exit(BD.debugOptimizerCrash());
117 // If the prefix maintains the predicate by itself, only keep the prefix!
118 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", false, &Error);
120 return InternalError;
122 outs() << " nope.\n";
123 sys::fs::remove(BitcodeResult);
126 outs() << " yup.\n"; // No miscompilation!
128 // Ok, so now we know that the prefix passes work, try running the suffix
129 // passes on the result of the prefix passes.
131 OwningPtr<Module> PrefixOutput(ParseInputFile(BitcodeResult,
134 errs() << BD.getToolName() << ": Error reading bitcode file '"
135 << BitcodeResult << "'!\n";
138 sys::fs::remove(BitcodeResult);
140 // Don't check if there are no passes in the suffix.
144 outs() << "Checking to see if '" << getPassesString(Suffix)
145 << "' passes compile correctly after the '"
146 << getPassesString(Prefix) << "' passes: ";
148 OwningPtr<Module> OriginalInput(BD.swapProgramIn(PrefixOutput.take()));
149 if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/,
151 errs() << " Error running this sequence of passes"
152 << " on the input program!\n";
153 BD.setPassesToRun(Suffix);
154 BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false);
155 exit(BD.debugOptimizerCrash());
159 Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "",
160 true /*delete bitcode*/, &Error);
162 return InternalError;
164 outs() << " nope.\n";
168 // Otherwise, we must not be running the bad pass anymore.
169 outs() << " yup.\n"; // No miscompilation!
170 // Restore orig program & free test.
171 delete BD.swapProgramIn(OriginalInput.take());
176 class ReduceMiscompilingFunctions : public ListReducer<Function*> {
178 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
180 ReduceMiscompilingFunctions(BugDriver &bd,
181 bool (*F)(BugDriver &, Module *, Module *,
183 : BD(bd), TestFn(F) {}
185 virtual TestResult doTest(std::vector<Function*> &Prefix,
186 std::vector<Function*> &Suffix,
187 std::string &Error) {
188 if (!Suffix.empty()) {
189 bool Ret = TestFuncs(Suffix, Error);
191 return InternalError;
195 if (!Prefix.empty()) {
196 bool Ret = TestFuncs(Prefix, Error);
198 return InternalError;
205 bool TestFuncs(const std::vector<Function*> &Prefix, std::string &Error);
209 /// TestMergedProgram - Given two modules, link them together and run the
210 /// program, checking to see if the program matches the diff. If there is
211 /// an error, return NULL. If not, return the merged module. The Broken argument
212 /// will be set to true if the output is different. If the DeleteInputs
213 /// argument is set to true then this function deletes both input
214 /// modules before it returns.
216 static Module *TestMergedProgram(const BugDriver &BD, Module *M1, Module *M2,
217 bool DeleteInputs, std::string &Error,
219 // Link the two portions of the program back to together.
220 std::string ErrorMsg;
222 M1 = CloneModule(M1);
223 M2 = CloneModule(M2);
225 if (Linker::LinkModules(M1, M2, Linker::DestroySource, &ErrorMsg)) {
226 errs() << BD.getToolName() << ": Error linking modules together:"
230 delete M2; // We are done with this module.
232 // Execute the program.
233 Broken = BD.diffProgram(M1, "", "", false, &Error);
234 if (!Error.empty()) {
235 // Delete the linked module
242 /// TestFuncs - split functions in a Module into two groups: those that are
243 /// under consideration for miscompilation vs. those that are not, and test
244 /// accordingly. Each group of functions becomes a separate Module.
246 bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs,
247 std::string &Error) {
248 // Test to see if the function is misoptimized if we ONLY run it on the
249 // functions listed in Funcs.
250 outs() << "Checking to see if the program is misoptimized when "
251 << (Funcs.size()==1 ? "this function is" : "these functions are")
252 << " run through the pass"
253 << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":";
254 PrintFunctionList(Funcs);
257 // Create a clone for two reasons:
258 // * If the optimization passes delete any function, the deleted function
259 // will be in the clone and Funcs will still point to valid memory
260 // * If the optimization passes use interprocedural information to break
261 // a function, we want to continue with the original function. Otherwise
262 // we can conclude that a function triggers the bug when in fact one
263 // needs a larger set of original functions to do so.
264 ValueToValueMapTy VMap;
265 Module *Clone = CloneModule(BD.getProgram(), VMap);
266 Module *Orig = BD.swapProgramIn(Clone);
268 std::vector<Function*> FuncsOnClone;
269 for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
270 Function *F = cast<Function>(VMap[Funcs[i]]);
271 FuncsOnClone.push_back(F);
274 // Split the module into the two halves of the program we want.
276 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
277 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, FuncsOnClone,
280 // Run the predicate, note that the predicate will delete both input modules.
281 bool Broken = TestFn(BD, ToOptimize, ToNotOptimize, Error);
283 delete BD.swapProgramIn(Orig);
288 /// DisambiguateGlobalSymbols - Give anonymous global values names.
290 static void DisambiguateGlobalSymbols(Module *M) {
291 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
294 I->setName("anon_global");
295 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
297 I->setName("anon_fn");
300 /// ExtractLoops - Given a reduced list of functions that still exposed the bug,
301 /// check to see if we can extract the loops in the region without obscuring the
302 /// bug. If so, it reduces the amount of code identified.
304 static bool ExtractLoops(BugDriver &BD,
305 bool (*TestFn)(BugDriver &, Module *, Module *,
307 std::vector<Function*> &MiscompiledFunctions,
308 std::string &Error) {
309 bool MadeChange = false;
311 if (BugpointIsInterrupted) return MadeChange;
313 ValueToValueMapTy VMap;
314 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
315 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
316 MiscompiledFunctions,
318 Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize);
319 if (!ToOptimizeLoopExtracted) {
320 // If the loop extractor crashed or if there were no extractible loops,
321 // then this chapter of our odyssey is over with.
322 delete ToNotOptimize;
327 errs() << "Extracted a loop from the breaking portion of the program.\n";
329 // Bugpoint is intentionally not very trusting of LLVM transformations. In
330 // particular, we're not going to assume that the loop extractor works, so
331 // we're going to test the newly loop extracted program to make sure nothing
332 // has broken. If something broke, then we'll inform the user and stop
334 AbstractInterpreter *AI = BD.switchToSafeInterpreter();
336 Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize,
337 false, Error, Failure);
341 // Delete the original and set the new program.
342 Module *Old = BD.swapProgramIn(New);
343 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
344 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
348 BD.switchToInterpreter(AI);
350 // Merged program doesn't work anymore!
351 errs() << " *** ERROR: Loop extraction broke the program. :("
352 << " Please report a bug!\n";
353 errs() << " Continuing on with un-loop-extracted version.\n";
355 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc",
357 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc",
359 BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc",
360 ToOptimizeLoopExtracted);
362 errs() << "Please submit the "
363 << OutputPrefix << "-loop-extract-fail-*.bc files.\n";
365 delete ToNotOptimize;
366 delete ToOptimizeLoopExtracted;
370 BD.switchToInterpreter(AI);
372 outs() << " Testing after loop extraction:\n";
373 // Clone modules, the tester function will free them.
374 Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted, VMap);
375 Module *TNOBackup = CloneModule(ToNotOptimize, VMap);
377 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
378 MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]);
380 Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error);
384 ToOptimizeLoopExtracted = TOLEBackup;
385 ToNotOptimize = TNOBackup;
388 outs() << "*** Loop extraction masked the problem. Undoing.\n";
389 // If the program is not still broken, then loop extraction did something
390 // that masked the error. Stop loop extraction now.
392 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
393 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) {
394 Function *F = MiscompiledFunctions[i];
395 MisCompFunctions.push_back(std::make_pair(F->getName(),
396 F->getFunctionType()));
399 std::string ErrorMsg;
400 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted,
401 Linker::DestroySource, &ErrorMsg)){
402 errs() << BD.getToolName() << ": Error linking modules together:"
407 MiscompiledFunctions.clear();
408 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
409 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
411 assert(NewF && "Function not found??");
412 MiscompiledFunctions.push_back(NewF);
415 delete ToOptimizeLoopExtracted;
416 BD.setNewProgram(ToNotOptimize);
420 outs() << "*** Loop extraction successful!\n";
422 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
423 for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
424 E = ToOptimizeLoopExtracted->end(); I != E; ++I)
425 if (!I->isDeclaration())
426 MisCompFunctions.push_back(std::make_pair(I->getName(),
427 I->getFunctionType()));
429 // Okay, great! Now we know that we extracted a loop and that loop
430 // extraction both didn't break the program, and didn't mask the problem.
431 // Replace the current program with the loop extracted version, and try to
432 // extract another loop.
433 std::string ErrorMsg;
434 if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted,
435 Linker::DestroySource, &ErrorMsg)){
436 errs() << BD.getToolName() << ": Error linking modules together:"
440 delete ToOptimizeLoopExtracted;
442 // All of the Function*'s in the MiscompiledFunctions list are in the old
443 // module. Update this list to include all of the functions in the
444 // optimized and loop extracted module.
445 MiscompiledFunctions.clear();
446 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
447 Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first);
449 assert(NewF && "Function not found??");
450 MiscompiledFunctions.push_back(NewF);
453 BD.setNewProgram(ToNotOptimize);
459 class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> {
461 bool (*TestFn)(BugDriver &, Module *, Module *, std::string &);
462 std::vector<Function*> FunctionsBeingTested;
464 ReduceMiscompiledBlocks(BugDriver &bd,
465 bool (*F)(BugDriver &, Module *, Module *,
467 const std::vector<Function*> &Fns)
468 : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {}
470 virtual TestResult doTest(std::vector<BasicBlock*> &Prefix,
471 std::vector<BasicBlock*> &Suffix,
472 std::string &Error) {
473 if (!Suffix.empty()) {
474 bool Ret = TestFuncs(Suffix, Error);
476 return InternalError;
480 if (!Prefix.empty()) {
481 bool Ret = TestFuncs(Prefix, Error);
483 return InternalError;
490 bool TestFuncs(const std::vector<BasicBlock*> &BBs, std::string &Error);
494 /// TestFuncs - Extract all blocks for the miscompiled functions except for the
495 /// specified blocks. If the problem still exists, return true.
497 bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs,
498 std::string &Error) {
499 // Test to see if the function is misoptimized if we ONLY run it on the
500 // functions listed in Funcs.
501 outs() << "Checking to see if the program is misoptimized when all ";
503 outs() << "but these " << BBs.size() << " blocks are extracted: ";
504 for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i)
505 outs() << BBs[i]->getName() << " ";
506 if (BBs.size() > 10) outs() << "...";
508 outs() << "blocks are extracted.";
512 // Split the module into the two halves of the program we want.
513 ValueToValueMapTy VMap;
514 Module *Clone = CloneModule(BD.getProgram(), VMap);
515 Module *Orig = BD.swapProgramIn(Clone);
516 std::vector<Function*> FuncsOnClone;
517 std::vector<BasicBlock*> BBsOnClone;
518 for (unsigned i = 0, e = FunctionsBeingTested.size(); i != e; ++i) {
519 Function *F = cast<Function>(VMap[FunctionsBeingTested[i]]);
520 FuncsOnClone.push_back(F);
522 for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
523 BasicBlock *BB = cast<BasicBlock>(VMap[BBs[i]]);
524 BBsOnClone.push_back(BB);
528 Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap);
529 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
533 // Try the extraction. If it doesn't work, then the block extractor crashed
534 // or something, in which case bugpoint can't chase down this possibility.
535 if (Module *New = BD.ExtractMappedBlocksFromModule(BBsOnClone, ToOptimize)) {
537 // Run the predicate,
538 // note that the predicate will delete both input modules.
539 bool Ret = TestFn(BD, New, ToNotOptimize, Error);
540 delete BD.swapProgramIn(Orig);
543 delete BD.swapProgramIn(Orig);
545 delete ToNotOptimize;
550 /// ExtractBlocks - Given a reduced list of functions that still expose the bug,
551 /// extract as many basic blocks from the region as possible without obscuring
554 static bool ExtractBlocks(BugDriver &BD,
555 bool (*TestFn)(BugDriver &, Module *, Module *,
557 std::vector<Function*> &MiscompiledFunctions,
558 std::string &Error) {
559 if (BugpointIsInterrupted) return false;
561 std::vector<BasicBlock*> Blocks;
562 for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i)
563 for (Function::iterator I = MiscompiledFunctions[i]->begin(),
564 E = MiscompiledFunctions[i]->end(); I != E; ++I)
567 // Use the list reducer to identify blocks that can be extracted without
568 // obscuring the bug. The Blocks list will end up containing blocks that must
569 // be retained from the original program.
570 unsigned OldSize = Blocks.size();
572 // Check to see if all blocks are extractible first.
573 bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions)
574 .TestFuncs(std::vector<BasicBlock*>(), Error);
580 ReduceMiscompiledBlocks(BD, TestFn,
581 MiscompiledFunctions).reduceList(Blocks, Error);
584 if (Blocks.size() == OldSize)
588 ValueToValueMapTy VMap;
589 Module *ProgClone = CloneModule(BD.getProgram(), VMap);
590 Module *ToExtract = SplitFunctionsOutOfModule(ProgClone,
591 MiscompiledFunctions,
593 Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract);
594 if (Extracted == 0) {
595 // Weird, extraction should have worked.
596 errs() << "Nondeterministic problem extracting blocks??\n";
602 // Otherwise, block extraction succeeded. Link the two program fragments back
606 std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
607 for (Module::iterator I = Extracted->begin(), E = Extracted->end();
609 if (!I->isDeclaration())
610 MisCompFunctions.push_back(std::make_pair(I->getName(),
611 I->getFunctionType()));
613 std::string ErrorMsg;
614 if (Linker::LinkModules(ProgClone, Extracted, Linker::DestroySource,
616 errs() << BD.getToolName() << ": Error linking modules together:"
622 // Set the new program and delete the old one.
623 BD.setNewProgram(ProgClone);
625 // Update the list of miscompiled functions.
626 MiscompiledFunctions.clear();
628 for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) {
629 Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first);
630 assert(NewF && "Function not found??");
631 MiscompiledFunctions.push_back(NewF);
638 /// DebugAMiscompilation - This is a generic driver to narrow down
639 /// miscompilations, either in an optimization or a code generator.
641 static std::vector<Function*>
642 DebugAMiscompilation(BugDriver &BD,
643 bool (*TestFn)(BugDriver &, Module *, Module *,
645 std::string &Error) {
646 // Okay, now that we have reduced the list of passes which are causing the
647 // failure, see if we can pin down which functions are being
648 // miscompiled... first build a list of all of the non-external functions in
650 std::vector<Function*> MiscompiledFunctions;
651 Module *Prog = BD.getProgram();
652 for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I)
653 if (!I->isDeclaration())
654 MiscompiledFunctions.push_back(I);
656 // Do the reduction...
657 if (!BugpointIsInterrupted)
658 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
660 if (!Error.empty()) {
661 errs() << "\n***Cannot reduce functions: ";
662 return MiscompiledFunctions;
664 outs() << "\n*** The following function"
665 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
666 << " being miscompiled: ";
667 PrintFunctionList(MiscompiledFunctions);
670 // See if we can rip any loops out of the miscompiled functions and still
671 // trigger the problem.
673 if (!BugpointIsInterrupted && !DisableLoopExtraction) {
674 bool Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions, Error);
676 return MiscompiledFunctions;
678 // Okay, we extracted some loops and the problem still appears. See if
679 // we can eliminate some of the created functions from being candidates.
680 DisambiguateGlobalSymbols(BD.getProgram());
682 // Do the reduction...
683 if (!BugpointIsInterrupted)
684 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
687 return MiscompiledFunctions;
689 outs() << "\n*** The following function"
690 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
691 << " being miscompiled: ";
692 PrintFunctionList(MiscompiledFunctions);
697 if (!BugpointIsInterrupted && !DisableBlockExtraction) {
698 bool Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions, Error);
700 return MiscompiledFunctions;
702 // Okay, we extracted some blocks and the problem still appears. See if
703 // we can eliminate some of the created functions from being candidates.
704 DisambiguateGlobalSymbols(BD.getProgram());
706 // Do the reduction...
707 ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions,
710 return MiscompiledFunctions;
712 outs() << "\n*** The following function"
713 << (MiscompiledFunctions.size() == 1 ? " is" : "s are")
714 << " being miscompiled: ";
715 PrintFunctionList(MiscompiledFunctions);
720 return MiscompiledFunctions;
723 /// TestOptimizer - This is the predicate function used to check to see if the
724 /// "Test" portion of the program is misoptimized. If so, return true. In any
725 /// case, both module arguments are deleted.
727 static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe,
728 std::string &Error) {
729 // Run the optimization passes on ToOptimize, producing a transformed version
730 // of the functions being tested.
731 outs() << " Optimizing functions being tested: ";
732 Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(),
733 /*AutoDebugCrashes*/true);
737 outs() << " Checking to see if the merged program executes correctly: ";
739 Module *New = TestMergedProgram(BD, Optimized, Safe, true, Error, Broken);
741 outs() << (Broken ? " nope.\n" : " yup.\n");
742 // Delete the original and set the new program.
743 delete BD.swapProgramIn(New);
749 /// debugMiscompilation - This method is used when the passes selected are not
750 /// crashing, but the generated output is semantically different from the
753 void BugDriver::debugMiscompilation(std::string *Error) {
754 // Make sure something was miscompiled...
755 if (!BugpointIsInterrupted)
756 if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun, *Error)) {
758 errs() << "*** Optimized program matches reference output! No problem"
759 << " detected...\nbugpoint can't help you with your problem!\n";
763 outs() << "\n*** Found miscompiling pass"
764 << (getPassesToRun().size() == 1 ? "" : "es") << ": "
765 << getPassesString(getPassesToRun()) << '\n';
766 EmitProgressBitcode(Program, "passinput");
768 std::vector<Function *> MiscompiledFunctions =
769 DebugAMiscompilation(*this, TestOptimizer, *Error);
773 // Output a bunch of bitcode files for the user...
774 outs() << "Outputting reduced bitcode files which expose the problem:\n";
775 ValueToValueMapTy VMap;
776 Module *ToNotOptimize = CloneModule(getProgram(), VMap);
777 Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize,
778 MiscompiledFunctions,
781 outs() << " Non-optimized portion: ";
782 EmitProgressBitcode(ToNotOptimize, "tonotoptimize", true);
783 delete ToNotOptimize; // Delete hacked module.
785 outs() << " Portion that is input to optimizer: ";
786 EmitProgressBitcode(ToOptimize, "tooptimize");
787 delete ToOptimize; // Delete hacked module.
792 /// CleanupAndPrepareModules - Get the specified modules ready for code
793 /// generator testing.
795 static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
797 // Clean up the modules, removing extra cruft that we don't need anymore...
798 Test = BD.performFinalCleanups(Test);
800 // If we are executing the JIT, we have several nasty issues to take care of.
801 if (!BD.isExecutingJIT()) return;
803 // First, if the main function is in the Safe module, we must add a stub to
804 // the Test module to call into it. Thus, we create a new function `main'
805 // which just calls the old one.
806 if (Function *oldMain = Safe->getFunction("main"))
807 if (!oldMain->isDeclaration()) {
809 oldMain->setName("llvm_bugpoint_old_main");
810 // Create a NEW `main' function with same type in the test module.
811 Function *newMain = Function::Create(oldMain->getFunctionType(),
812 GlobalValue::ExternalLinkage,
814 // Create an `oldmain' prototype in the test module, which will
815 // corresponds to the real main function in the same module.
816 Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
817 GlobalValue::ExternalLinkage,
818 oldMain->getName(), Test);
819 // Set up and remember the argument list for the main function.
820 std::vector<Value*> args;
821 for (Function::arg_iterator
822 I = newMain->arg_begin(), E = newMain->arg_end(),
823 OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
824 I->setName(OI->getName()); // Copy argument names from oldMain
828 // Call the old main function and return its result
829 BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
830 CallInst *call = CallInst::Create(oldMainProto, args, "", BB);
832 // If the type of old function wasn't void, return value of call
833 ReturnInst::Create(Safe->getContext(), call, BB);
836 // The second nasty issue we must deal with in the JIT is that the Safe
837 // module cannot directly reference any functions defined in the test
838 // module. Instead, we use a JIT API call to dynamically resolve the
841 // Add the resolver to the Safe module.
842 // Prototype: void *getPointerToNamedFunction(const char* Name)
843 Constant *resolverFunc =
844 Safe->getOrInsertFunction("getPointerToNamedFunction",
845 Type::getInt8PtrTy(Safe->getContext()),
846 Type::getInt8PtrTy(Safe->getContext()),
849 // Use the function we just added to get addresses of functions we need.
850 for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
851 if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
852 !F->isIntrinsic() /* ignore intrinsics */) {
853 Function *TestFn = Test->getFunction(F->getName());
855 // Don't forward functions which are external in the test module too.
856 if (TestFn && !TestFn->isDeclaration()) {
857 // 1. Add a string constant with its name to the global file
858 Constant *InitArray =
859 ConstantDataArray::getString(F->getContext(), F->getName());
860 GlobalVariable *funcName =
861 new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
862 GlobalValue::InternalLinkage, InitArray,
863 F->getName() + "_name");
865 // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
866 // sbyte* so it matches the signature of the resolver function.
868 // GetElementPtr *funcName, ulong 0, ulong 0
869 std::vector<Constant*> GEPargs(2,
870 Constant::getNullValue(Type::getInt32Ty(F->getContext())));
871 Value *GEP = ConstantExpr::getGetElementPtr(funcName, GEPargs);
872 std::vector<Value*> ResolverArgs;
873 ResolverArgs.push_back(GEP);
875 // Rewrite uses of F in global initializers, etc. to uses of a wrapper
876 // function that dynamically resolves the calls to F via our JIT API
877 if (!F->use_empty()) {
878 // Create a new global to hold the cached function pointer.
879 Constant *NullPtr = ConstantPointerNull::get(F->getType());
880 GlobalVariable *Cache =
881 new GlobalVariable(*F->getParent(), F->getType(),
882 false, GlobalValue::InternalLinkage,
883 NullPtr,F->getName()+".fpcache");
885 // Construct a new stub function that will re-route calls to F
886 FunctionType *FuncTy = F->getFunctionType();
887 Function *FuncWrapper = Function::Create(FuncTy,
888 GlobalValue::InternalLinkage,
889 F->getName() + "_wrapper",
891 BasicBlock *EntryBB = BasicBlock::Create(F->getContext(),
892 "entry", FuncWrapper);
893 BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(),
894 "usecache", FuncWrapper);
895 BasicBlock *LookupBB = BasicBlock::Create(F->getContext(),
896 "lookupfp", FuncWrapper);
898 // Check to see if we already looked up the value.
899 Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
900 Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
902 BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
904 // Resolve the call to function F via the JIT API:
906 // call resolver(GetElementPtr...)
908 CallInst::Create(resolverFunc, ResolverArgs, "resolver", LookupBB);
910 // Cast the result from the resolver to correctly-typed function.
911 CastInst *CastedResolver =
912 new BitCastInst(Resolver,
913 PointerType::getUnqual(F->getFunctionType()),
914 "resolverCast", LookupBB);
916 // Save the value in our cache.
917 new StoreInst(CastedResolver, Cache, LookupBB);
918 BranchInst::Create(DoCallBB, LookupBB);
920 PHINode *FuncPtr = PHINode::Create(NullPtr->getType(), 2,
922 FuncPtr->addIncoming(CastedResolver, LookupBB);
923 FuncPtr->addIncoming(CachedVal, EntryBB);
925 // Save the argument list.
926 std::vector<Value*> Args;
927 for (Function::arg_iterator i = FuncWrapper->arg_begin(),
928 e = FuncWrapper->arg_end(); i != e; ++i)
931 // Pass on the arguments to the real function, return its result
932 if (F->getReturnType()->isVoidTy()) {
933 CallInst::Create(FuncPtr, Args, "", DoCallBB);
934 ReturnInst::Create(F->getContext(), DoCallBB);
936 CallInst *Call = CallInst::Create(FuncPtr, Args,
938 ReturnInst::Create(F->getContext(),Call, DoCallBB);
941 // Use the wrapper function instead of the old function
942 F->replaceAllUsesWith(FuncWrapper);
948 if (verifyModule(*Test) || verifyModule(*Safe)) {
949 errs() << "Bugpoint has a bug, which corrupted a module!!\n";
956 /// TestCodeGenerator - This is the predicate function used to check to see if
957 /// the "Test" portion of the program is miscompiled by the code generator under
958 /// test. If so, return true. In any case, both module arguments are deleted.
960 static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe,
961 std::string &Error) {
962 CleanupAndPrepareModules(BD, Test, Safe);
964 SmallString<128> TestModuleBC;
966 error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
967 TestModuleFD, TestModuleBC);
969 errs() << BD.getToolName() << "Error making unique filename: "
970 << EC.message() << "\n";
973 if (BD.writeProgramToFile(TestModuleBC.str(), TestModuleFD, Test)) {
974 errs() << "Error writing bitcode to `" << TestModuleBC.str()
980 FileRemover TestModuleBCRemover(TestModuleBC.str(), !SaveTemps);
982 // Make the shared library
983 SmallString<128> SafeModuleBC;
985 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
988 errs() << BD.getToolName() << "Error making unique filename: "
989 << EC.message() << "\n";
993 if (BD.writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, Safe)) {
994 errs() << "Error writing bitcode to `" << SafeModuleBC.str()
999 FileRemover SafeModuleBCRemover(SafeModuleBC.str(), !SaveTemps);
1001 std::string SharedObject = BD.compileSharedObject(SafeModuleBC.str(), Error);
1006 FileRemover SharedObjectRemover(SharedObject, !SaveTemps);
1008 // Run the code generator on the `Test' code, loading the shared library.
1009 // The function returns whether or not the new output differs from reference.
1010 bool Result = BD.diffProgram(BD.getProgram(), TestModuleBC.str(),
1011 SharedObject, false, &Error);
1016 errs() << ": still failing!\n";
1018 errs() << ": didn't fail.\n";
1024 /// debugCodeGenerator - debug errors in LLC, LLI, or CBE.
1026 bool BugDriver::debugCodeGenerator(std::string *Error) {
1027 if ((void*)SafeInterpreter == (void*)Interpreter) {
1028 std::string Result = executeProgramSafely(Program, "bugpoint.safe.out",
1030 if (Error->empty()) {
1031 outs() << "\n*** The \"safe\" i.e. 'known good' backend cannot match "
1032 << "the reference diff. This may be due to a\n front-end "
1033 << "bug or a bug in the original program, but this can also "
1034 << "happen if bugpoint isn't running the program with the "
1035 << "right flags or input.\n I left the result of executing "
1036 << "the program with the \"safe\" backend in this file for "
1038 << Result << "'.\n";
1043 DisambiguateGlobalSymbols(Program);
1045 std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator,
1047 if (!Error->empty())
1050 // Split the module into the two halves of the program we want.
1051 ValueToValueMapTy VMap;
1052 Module *ToNotCodeGen = CloneModule(getProgram(), VMap);
1053 Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, VMap);
1055 // Condition the modules
1056 CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen);
1058 SmallString<128> TestModuleBC;
1060 error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
1061 TestModuleFD, TestModuleBC);
1063 errs() << getToolName() << "Error making unique filename: "
1064 << EC.message() << "\n";
1068 if (writeProgramToFile(TestModuleBC.str(), TestModuleFD, ToCodeGen)) {
1069 errs() << "Error writing bitcode to `" << TestModuleBC.str()
1075 // Make the shared library
1076 SmallString<128> SafeModuleBC;
1078 EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD,
1081 errs() << getToolName() << "Error making unique filename: "
1082 << EC.message() << "\n";
1086 if (writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, ToNotCodeGen)) {
1087 errs() << "Error writing bitcode to `" << SafeModuleBC.str()
1091 std::string SharedObject = compileSharedObject(SafeModuleBC.str(), *Error);
1092 if (!Error->empty())
1094 delete ToNotCodeGen;
1096 outs() << "You can reproduce the problem with the command line: \n";
1097 if (isExecutingJIT()) {
1098 outs() << " lli -load " << SharedObject << " " << TestModuleBC.str();
1100 outs() << " llc " << TestModuleBC.str() << " -o " << TestModuleBC.str()
1102 outs() << " gcc " << SharedObject << " " << TestModuleBC.str()
1103 << ".s -o " << TestModuleBC.str() << ".exe";
1104 #if defined (HAVE_LINK_R)
1105 outs() << " -Wl,-R.";
1108 outs() << " " << TestModuleBC.str() << ".exe";
1110 for (unsigned i = 0, e = InputArgv.size(); i != e; ++i)
1111 outs() << " " << InputArgv[i];
1113 outs() << "The shared object was created with:\n llc -march=c "
1114 << SafeModuleBC.str() << " -o temporary.c\n"
1115 << " gcc -xc temporary.c -O2 -o " << SharedObject;
1116 if (TargetTriple.getArch() == Triple::sparc)
1117 outs() << " -G"; // Compile a shared library, `-G' for Sparc
1119 outs() << " -fPIC -shared"; // `-shared' for Linux/X86, maybe others
1121 outs() << " -fno-strict-aliasing\n";