| //===- Miscompilation.cpp - Debug program miscompilations -----------------===// | |
| // | |
| // The LLVM Compiler Infrastructure | |
| // | |
| // This file is distributed under the University of Illinois Open Source | |
| // License. See LICENSE.TXT for details. | |
| // | |
| //===----------------------------------------------------------------------===// | |
| // | |
| // This file implements optimizer and code generation miscompilation debugging | |
| // support. | |
| // | |
| //===----------------------------------------------------------------------===// | |
| #include "BugDriver.h" | |
| #include "ListReducer.h" | |
| #include "ToolRunner.h" | |
| #include "llvm/Constants.h" | |
| #include "llvm/DerivedTypes.h" | |
| #include "llvm/Instructions.h" | |
| #include "llvm/Linker.h" | |
| #include "llvm/Module.h" | |
| #include "llvm/Pass.h" | |
| #include "llvm/Analysis/Verifier.h" | |
| #include "llvm/Transforms/Utils/Cloning.h" | |
| #include "llvm/Support/CommandLine.h" | |
| #include "llvm/Support/FileUtilities.h" | |
| #include "llvm/Config/config.h" // for HAVE_LINK_R | |
| using namespace llvm; | |
| namespace llvm { | |
| extern cl::opt<std::string> OutputPrefix; | |
| extern cl::list<std::string> InputArgv; | |
| } | |
| namespace { | |
| static llvm::cl::opt<bool> | |
| DisableLoopExtraction("disable-loop-extraction", | |
| cl::desc("Don't extract loops when searching for miscompilations"), | |
| cl::init(false)); | |
| static llvm::cl::opt<bool> | |
| DisableBlockExtraction("disable-block-extraction", | |
| cl::desc("Don't extract blocks when searching for miscompilations"), | |
| cl::init(false)); | |
| class ReduceMiscompilingPasses : public ListReducer<std::string> { | |
| BugDriver &BD; | |
| public: | |
| ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {} | |
| virtual TestResult doTest(std::vector<std::string> &Prefix, | |
| std::vector<std::string> &Suffix, | |
| std::string &Error); | |
| }; | |
| } | |
| /// TestResult - After passes have been split into a test group and a control | |
| /// group, see if they still break the program. | |
| /// | |
| ReduceMiscompilingPasses::TestResult | |
| ReduceMiscompilingPasses::doTest(std::vector<std::string> &Prefix, | |
| std::vector<std::string> &Suffix, | |
| std::string &Error) { | |
| // First, run the program with just the Suffix passes. If it is still broken | |
| // with JUST the kept passes, discard the prefix passes. | |
| outs() << "Checking to see if '" << getPassesString(Suffix) | |
| << "' compiles correctly: "; | |
| std::string BitcodeResult; | |
| if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/, | |
| true/*quiet*/)) { | |
| errs() << " Error running this sequence of passes" | |
| << " on the input program!\n"; | |
| BD.setPassesToRun(Suffix); | |
| BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false); | |
| exit(BD.debugOptimizerCrash()); | |
| } | |
| // Check to see if the finished program matches the reference output... | |
| bool Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", | |
| true /*delete bitcode*/, &Error); | |
| if (!Error.empty()) | |
| return InternalError; | |
| if (Diff) { | |
| outs() << " nope.\n"; | |
| if (Suffix.empty()) { | |
| errs() << BD.getToolName() << ": I'm confused: the test fails when " | |
| << "no passes are run, nondeterministic program?\n"; | |
| exit(1); | |
| } | |
| return KeepSuffix; // Miscompilation detected! | |
| } | |
| outs() << " yup.\n"; // No miscompilation! | |
| if (Prefix.empty()) return NoFailure; | |
| // Next, see if the program is broken if we run the "prefix" passes first, | |
| // then separately run the "kept" passes. | |
| outs() << "Checking to see if '" << getPassesString(Prefix) | |
| << "' compiles correctly: "; | |
| // If it is not broken with the kept passes, it's possible that the prefix | |
| // passes must be run before the kept passes to break it. If the program | |
| // WORKS after the prefix passes, but then fails if running the prefix AND | |
| // kept passes, we can update our bitcode file to include the result of the | |
| // prefix passes, then discard the prefix passes. | |
| // | |
| if (BD.runPasses(BD.getProgram(), Prefix, BitcodeResult, false/*delete*/, | |
| true/*quiet*/)) { | |
| errs() << " Error running this sequence of passes" | |
| << " on the input program!\n"; | |
| BD.setPassesToRun(Prefix); | |
| BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false); | |
| exit(BD.debugOptimizerCrash()); | |
| } | |
| // If the prefix maintains the predicate by itself, only keep the prefix! | |
| Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", false, &Error); | |
| if (!Error.empty()) | |
| return InternalError; | |
| if (Diff) { | |
| outs() << " nope.\n"; | |
| sys::Path(BitcodeResult).eraseFromDisk(); | |
| return KeepPrefix; | |
| } | |
| outs() << " yup.\n"; // No miscompilation! | |
| // Ok, so now we know that the prefix passes work, try running the suffix | |
| // passes on the result of the prefix passes. | |
| // | |
| OwningPtr<Module> PrefixOutput(ParseInputFile(BitcodeResult, | |
| BD.getContext())); | |
| if (PrefixOutput == 0) { | |
| errs() << BD.getToolName() << ": Error reading bitcode file '" | |
| << BitcodeResult << "'!\n"; | |
| exit(1); | |
| } | |
| sys::Path(BitcodeResult).eraseFromDisk(); // No longer need the file on disk | |
| // Don't check if there are no passes in the suffix. | |
| if (Suffix.empty()) | |
| return NoFailure; | |
| outs() << "Checking to see if '" << getPassesString(Suffix) | |
| << "' passes compile correctly after the '" | |
| << getPassesString(Prefix) << "' passes: "; | |
| OwningPtr<Module> OriginalInput(BD.swapProgramIn(PrefixOutput.take())); | |
| if (BD.runPasses(BD.getProgram(), Suffix, BitcodeResult, false/*delete*/, | |
| true/*quiet*/)) { | |
| errs() << " Error running this sequence of passes" | |
| << " on the input program!\n"; | |
| BD.setPassesToRun(Suffix); | |
| BD.EmitProgressBitcode(BD.getProgram(), "pass-error", false); | |
| exit(BD.debugOptimizerCrash()); | |
| } | |
| // Run the result... | |
| Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", | |
| true /*delete bitcode*/, &Error); | |
| if (!Error.empty()) | |
| return InternalError; | |
| if (Diff) { | |
| outs() << " nope.\n"; | |
| return KeepSuffix; | |
| } | |
| // Otherwise, we must not be running the bad pass anymore. | |
| outs() << " yup.\n"; // No miscompilation! | |
| // Restore orig program & free test. | |
| delete BD.swapProgramIn(OriginalInput.take()); | |
| return NoFailure; | |
| } | |
| namespace { | |
| class ReduceMiscompilingFunctions : public ListReducer<Function*> { | |
| BugDriver &BD; | |
| bool (*TestFn)(BugDriver &, Module *, Module *, std::string &); | |
| public: | |
| ReduceMiscompilingFunctions(BugDriver &bd, | |
| bool (*F)(BugDriver &, Module *, Module *, | |
| std::string &)) | |
| : BD(bd), TestFn(F) {} | |
| virtual TestResult doTest(std::vector<Function*> &Prefix, | |
| std::vector<Function*> &Suffix, | |
| std::string &Error) { | |
| if (!Suffix.empty()) { | |
| bool Ret = TestFuncs(Suffix, Error); | |
| if (!Error.empty()) | |
| return InternalError; | |
| if (Ret) | |
| return KeepSuffix; | |
| } | |
| if (!Prefix.empty()) { | |
| bool Ret = TestFuncs(Prefix, Error); | |
| if (!Error.empty()) | |
| return InternalError; | |
| if (Ret) | |
| return KeepPrefix; | |
| } | |
| return NoFailure; | |
| } | |
| bool TestFuncs(const std::vector<Function*> &Prefix, std::string &Error); | |
| }; | |
| } | |
| /// TestMergedProgram - Given two modules, link them together and run the | |
| /// program, checking to see if the program matches the diff. If there is | |
| /// an error, return NULL. If not, return the merged module. The Broken argument | |
| /// will be set to true if the output is different. If the DeleteInputs | |
| /// argument is set to true then this function deletes both input | |
| /// modules before it returns. | |
| /// | |
| static Module *TestMergedProgram(const BugDriver &BD, Module *M1, Module *M2, | |
| bool DeleteInputs, std::string &Error, | |
| bool &Broken) { | |
| // Link the two portions of the program back to together. | |
| std::string ErrorMsg; | |
| if (!DeleteInputs) { | |
| M1 = CloneModule(M1); | |
| M2 = CloneModule(M2); | |
| } | |
| if (Linker::LinkModules(M1, M2, Linker::DestroySource, &ErrorMsg)) { | |
| errs() << BD.getToolName() << ": Error linking modules together:" | |
| << ErrorMsg << '\n'; | |
| exit(1); | |
| } | |
| delete M2; // We are done with this module. | |
| // Execute the program. | |
| Broken = BD.diffProgram(M1, "", "", false, &Error); | |
| if (!Error.empty()) { | |
| // Delete the linked module | |
| delete M1; | |
| return NULL; | |
| } | |
| return M1; | |
| } | |
| /// TestFuncs - split functions in a Module into two groups: those that are | |
| /// under consideration for miscompilation vs. those that are not, and test | |
| /// accordingly. Each group of functions becomes a separate Module. | |
| /// | |
| bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs, | |
| std::string &Error) { | |
| // Test to see if the function is misoptimized if we ONLY run it on the | |
| // functions listed in Funcs. | |
| outs() << "Checking to see if the program is misoptimized when " | |
| << (Funcs.size()==1 ? "this function is" : "these functions are") | |
| << " run through the pass" | |
| << (BD.getPassesToRun().size() == 1 ? "" : "es") << ":"; | |
| PrintFunctionList(Funcs); | |
| outs() << '\n'; | |
| // Create a clone for two reasons: | |
| // * If the optimization passes delete any function, the deleted function | |
| // will be in the clone and Funcs will still point to valid memory | |
| // * If the optimization passes use interprocedural information to break | |
| // a function, we want to continue with the original function. Otherwise | |
| // we can conclude that a function triggers the bug when in fact one | |
| // needs a larger set of original functions to do so. | |
| ValueToValueMapTy VMap; | |
| Module *Clone = CloneModule(BD.getProgram(), VMap); | |
| Module *Orig = BD.swapProgramIn(Clone); | |
| std::vector<Function*> FuncsOnClone; | |
| for (unsigned i = 0, e = Funcs.size(); i != e; ++i) { | |
| Function *F = cast<Function>(VMap[Funcs[i]]); | |
| FuncsOnClone.push_back(F); | |
| } | |
| // Split the module into the two halves of the program we want. | |
| VMap.clear(); | |
| Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap); | |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, FuncsOnClone, | |
| VMap); | |
| // Run the predicate, note that the predicate will delete both input modules. | |
| bool Broken = TestFn(BD, ToOptimize, ToNotOptimize, Error); | |
| delete BD.swapProgramIn(Orig); | |
| return Broken; | |
| } | |
| /// DisambiguateGlobalSymbols - Give anonymous global values names. | |
| /// | |
| static void DisambiguateGlobalSymbols(Module *M) { | |
| for (Module::global_iterator I = M->global_begin(), E = M->global_end(); | |
| I != E; ++I) | |
| if (!I->hasName()) | |
| I->setName("anon_global"); | |
| for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) | |
| if (!I->hasName()) | |
| I->setName("anon_fn"); | |
| } | |
| /// ExtractLoops - Given a reduced list of functions that still exposed the bug, | |
| /// check to see if we can extract the loops in the region without obscuring the | |
| /// bug. If so, it reduces the amount of code identified. | |
| /// | |
| static bool ExtractLoops(BugDriver &BD, | |
| bool (*TestFn)(BugDriver &, Module *, Module *, | |
| std::string &), | |
| std::vector<Function*> &MiscompiledFunctions, | |
| std::string &Error) { | |
| bool MadeChange = false; | |
| while (1) { | |
| if (BugpointIsInterrupted) return MadeChange; | |
| ValueToValueMapTy VMap; | |
| Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap); | |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, | |
| MiscompiledFunctions, | |
| VMap); | |
| Module *ToOptimizeLoopExtracted = BD.ExtractLoop(ToOptimize); | |
| if (!ToOptimizeLoopExtracted) { | |
| // If the loop extractor crashed or if there were no extractible loops, | |
| // then this chapter of our odyssey is over with. | |
| delete ToNotOptimize; | |
| delete ToOptimize; | |
| return MadeChange; | |
| } | |
| errs() << "Extracted a loop from the breaking portion of the program.\n"; | |
| // Bugpoint is intentionally not very trusting of LLVM transformations. In | |
| // particular, we're not going to assume that the loop extractor works, so | |
| // we're going to test the newly loop extracted program to make sure nothing | |
| // has broken. If something broke, then we'll inform the user and stop | |
| // extraction. | |
| AbstractInterpreter *AI = BD.switchToSafeInterpreter(); | |
| bool Failure; | |
| Module *New = TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, | |
| false, Error, Failure); | |
| if (!New) | |
| return false; | |
| // Delete the original and set the new program. | |
| delete BD.swapProgramIn(New); | |
| if (Failure) { | |
| BD.switchToInterpreter(AI); | |
| // Merged program doesn't work anymore! | |
| errs() << " *** ERROR: Loop extraction broke the program. :(" | |
| << " Please report a bug!\n"; | |
| errs() << " Continuing on with un-loop-extracted version.\n"; | |
| BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-tno.bc", | |
| ToNotOptimize); | |
| BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to.bc", | |
| ToOptimize); | |
| BD.writeProgramToFile(OutputPrefix + "-loop-extract-fail-to-le.bc", | |
| ToOptimizeLoopExtracted); | |
| errs() << "Please submit the " | |
| << OutputPrefix << "-loop-extract-fail-*.bc files.\n"; | |
| delete ToOptimize; | |
| delete ToNotOptimize; | |
| delete ToOptimizeLoopExtracted; | |
| return MadeChange; | |
| } | |
| delete ToOptimize; | |
| BD.switchToInterpreter(AI); | |
| outs() << " Testing after loop extraction:\n"; | |
| // Clone modules, the tester function will free them. | |
| Module *TOLEBackup = CloneModule(ToOptimizeLoopExtracted); | |
| Module *TNOBackup = CloneModule(ToNotOptimize); | |
| Failure = TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize, Error); | |
| if (!Error.empty()) | |
| return false; | |
| if (!Failure) { | |
| outs() << "*** Loop extraction masked the problem. Undoing.\n"; | |
| // If the program is not still broken, then loop extraction did something | |
| // that masked the error. Stop loop extraction now. | |
| delete TOLEBackup; | |
| delete TNOBackup; | |
| return MadeChange; | |
| } | |
| ToOptimizeLoopExtracted = TOLEBackup; | |
| ToNotOptimize = TNOBackup; | |
| outs() << "*** Loop extraction successful!\n"; | |
| std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions; | |
| for (Module::iterator I = ToOptimizeLoopExtracted->begin(), | |
| E = ToOptimizeLoopExtracted->end(); I != E; ++I) | |
| if (!I->isDeclaration()) | |
| MisCompFunctions.push_back(std::make_pair(I->getName(), | |
| I->getFunctionType())); | |
| // Okay, great! Now we know that we extracted a loop and that loop | |
| // extraction both didn't break the program, and didn't mask the problem. | |
| // Replace the current program with the loop extracted version, and try to | |
| // extract another loop. | |
| std::string ErrorMsg; | |
| if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted, | |
| Linker::DestroySource, &ErrorMsg)){ | |
| errs() << BD.getToolName() << ": Error linking modules together:" | |
| << ErrorMsg << '\n'; | |
| exit(1); | |
| } | |
| delete ToOptimizeLoopExtracted; | |
| // All of the Function*'s in the MiscompiledFunctions list are in the old | |
| // module. Update this list to include all of the functions in the | |
| // optimized and loop extracted module. | |
| MiscompiledFunctions.clear(); | |
| for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) { | |
| Function *NewF = ToNotOptimize->getFunction(MisCompFunctions[i].first); | |
| assert(NewF && "Function not found??"); | |
| MiscompiledFunctions.push_back(NewF); | |
| } | |
| BD.setNewProgram(ToNotOptimize); | |
| MadeChange = true; | |
| } | |
| } | |
| namespace { | |
| class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> { | |
| BugDriver &BD; | |
| bool (*TestFn)(BugDriver &, Module *, Module *, std::string &); | |
| std::vector<Function*> FunctionsBeingTested; | |
| public: | |
| ReduceMiscompiledBlocks(BugDriver &bd, | |
| bool (*F)(BugDriver &, Module *, Module *, | |
| std::string &), | |
| const std::vector<Function*> &Fns) | |
| : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {} | |
| virtual TestResult doTest(std::vector<BasicBlock*> &Prefix, | |
| std::vector<BasicBlock*> &Suffix, | |
| std::string &Error) { | |
| if (!Suffix.empty()) { | |
| bool Ret = TestFuncs(Suffix, Error); | |
| if (!Error.empty()) | |
| return InternalError; | |
| if (Ret) | |
| return KeepSuffix; | |
| } | |
| if (!Prefix.empty()) { | |
| bool Ret = TestFuncs(Prefix, Error); | |
| if (!Error.empty()) | |
| return InternalError; | |
| if (Ret) | |
| return KeepPrefix; | |
| } | |
| return NoFailure; | |
| } | |
| bool TestFuncs(const std::vector<BasicBlock*> &BBs, std::string &Error); | |
| }; | |
| } | |
| /// TestFuncs - Extract all blocks for the miscompiled functions except for the | |
| /// specified blocks. If the problem still exists, return true. | |
| /// | |
| bool ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock*> &BBs, | |
| std::string &Error) { | |
| // Test to see if the function is misoptimized if we ONLY run it on the | |
| // functions listed in Funcs. | |
| outs() << "Checking to see if the program is misoptimized when all "; | |
| if (!BBs.empty()) { | |
| outs() << "but these " << BBs.size() << " blocks are extracted: "; | |
| for (unsigned i = 0, e = BBs.size() < 10 ? BBs.size() : 10; i != e; ++i) | |
| outs() << BBs[i]->getName() << " "; | |
| if (BBs.size() > 10) outs() << "..."; | |
| } else { | |
| outs() << "blocks are extracted."; | |
| } | |
| outs() << '\n'; | |
| // Split the module into the two halves of the program we want. | |
| ValueToValueMapTy VMap; | |
| Module *Clone = CloneModule(BD.getProgram(), VMap); | |
| Module *Orig = BD.swapProgramIn(Clone); | |
| std::vector<Function*> FuncsOnClone; | |
| std::vector<BasicBlock*> BBsOnClone; | |
| for (unsigned i = 0, e = FunctionsBeingTested.size(); i != e; ++i) { | |
| Function *F = cast<Function>(VMap[FunctionsBeingTested[i]]); | |
| FuncsOnClone.push_back(F); | |
| } | |
| for (unsigned i = 0, e = BBs.size(); i != e; ++i) { | |
| BasicBlock *BB = cast<BasicBlock>(VMap[BBs[i]]); | |
| BBsOnClone.push_back(BB); | |
| } | |
| VMap.clear(); | |
| Module *ToNotOptimize = CloneModule(BD.getProgram(), VMap); | |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, | |
| FuncsOnClone, | |
| VMap); | |
| // Try the extraction. If it doesn't work, then the block extractor crashed | |
| // or something, in which case bugpoint can't chase down this possibility. | |
| if (Module *New = BD.ExtractMappedBlocksFromModule(BBsOnClone, ToOptimize)) { | |
| delete ToOptimize; | |
| // Run the predicate, | |
| // note that the predicate will delete both input modules. | |
| bool Ret = TestFn(BD, New, ToNotOptimize, Error); | |
| delete BD.swapProgramIn(Orig); | |
| return Ret; | |
| } | |
| delete BD.swapProgramIn(Orig); | |
| delete ToOptimize; | |
| delete ToNotOptimize; | |
| return false; | |
| } | |
| /// ExtractBlocks - Given a reduced list of functions that still expose the bug, | |
| /// extract as many basic blocks from the region as possible without obscuring | |
| /// the bug. | |
| /// | |
| static bool ExtractBlocks(BugDriver &BD, | |
| bool (*TestFn)(BugDriver &, Module *, Module *, | |
| std::string &), | |
| std::vector<Function*> &MiscompiledFunctions, | |
| std::string &Error) { | |
| if (BugpointIsInterrupted) return false; | |
| std::vector<BasicBlock*> Blocks; | |
| for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) | |
| for (Function::iterator I = MiscompiledFunctions[i]->begin(), | |
| E = MiscompiledFunctions[i]->end(); I != E; ++I) | |
| Blocks.push_back(I); | |
| // Use the list reducer to identify blocks that can be extracted without | |
| // obscuring the bug. The Blocks list will end up containing blocks that must | |
| // be retained from the original program. | |
| unsigned OldSize = Blocks.size(); | |
| // Check to see if all blocks are extractible first. | |
| bool Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions) | |
| .TestFuncs(std::vector<BasicBlock*>(), Error); | |
| if (!Error.empty()) | |
| return false; | |
| if (Ret) { | |
| Blocks.clear(); | |
| } else { | |
| ReduceMiscompiledBlocks(BD, TestFn, | |
| MiscompiledFunctions).reduceList(Blocks, Error); | |
| if (!Error.empty()) | |
| return false; | |
| if (Blocks.size() == OldSize) | |
| return false; | |
| } | |
| ValueToValueMapTy VMap; | |
| Module *ProgClone = CloneModule(BD.getProgram(), VMap); | |
| Module *ToExtract = SplitFunctionsOutOfModule(ProgClone, | |
| MiscompiledFunctions, | |
| VMap); | |
| Module *Extracted = BD.ExtractMappedBlocksFromModule(Blocks, ToExtract); | |
| if (Extracted == 0) { | |
| // Weird, extraction should have worked. | |
| errs() << "Nondeterministic problem extracting blocks??\n"; | |
| delete ProgClone; | |
| delete ToExtract; | |
| return false; | |
| } | |
| // Otherwise, block extraction succeeded. Link the two program fragments back | |
| // together. | |
| delete ToExtract; | |
| std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions; | |
| for (Module::iterator I = Extracted->begin(), E = Extracted->end(); | |
| I != E; ++I) | |
| if (!I->isDeclaration()) | |
| MisCompFunctions.push_back(std::make_pair(I->getName(), | |
| I->getFunctionType())); | |
| std::string ErrorMsg; | |
| if (Linker::LinkModules(ProgClone, Extracted, Linker::DestroySource, | |
| &ErrorMsg)) { | |
| errs() << BD.getToolName() << ": Error linking modules together:" | |
| << ErrorMsg << '\n'; | |
| exit(1); | |
| } | |
| delete Extracted; | |
| // Set the new program and delete the old one. | |
| BD.setNewProgram(ProgClone); | |
| // Update the list of miscompiled functions. | |
| MiscompiledFunctions.clear(); | |
| for (unsigned i = 0, e = MisCompFunctions.size(); i != e; ++i) { | |
| Function *NewF = ProgClone->getFunction(MisCompFunctions[i].first); | |
| assert(NewF && "Function not found??"); | |
| MiscompiledFunctions.push_back(NewF); | |
| } | |
| return true; | |
| } | |
| /// DebugAMiscompilation - This is a generic driver to narrow down | |
| /// miscompilations, either in an optimization or a code generator. | |
| /// | |
| static std::vector<Function*> | |
| DebugAMiscompilation(BugDriver &BD, | |
| bool (*TestFn)(BugDriver &, Module *, Module *, | |
| std::string &), | |
| std::string &Error) { | |
| // Okay, now that we have reduced the list of passes which are causing the | |
| // failure, see if we can pin down which functions are being | |
| // miscompiled... first build a list of all of the non-external functions in | |
| // the program. | |
| std::vector<Function*> MiscompiledFunctions; | |
| Module *Prog = BD.getProgram(); | |
| for (Module::iterator I = Prog->begin(), E = Prog->end(); I != E; ++I) | |
| if (!I->isDeclaration()) | |
| MiscompiledFunctions.push_back(I); | |
| // Do the reduction... | |
| if (!BugpointIsInterrupted) | |
| ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions, | |
| Error); | |
| if (!Error.empty()) { | |
| errs() << "\n***Cannot reduce functions: "; | |
| return MiscompiledFunctions; | |
| } | |
| outs() << "\n*** The following function" | |
| << (MiscompiledFunctions.size() == 1 ? " is" : "s are") | |
| << " being miscompiled: "; | |
| PrintFunctionList(MiscompiledFunctions); | |
| outs() << '\n'; | |
| // See if we can rip any loops out of the miscompiled functions and still | |
| // trigger the problem. | |
| if (!BugpointIsInterrupted && !DisableLoopExtraction) { | |
| bool Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions, Error); | |
| if (!Error.empty()) | |
| return MiscompiledFunctions; | |
| if (Ret) { | |
| // Okay, we extracted some loops and the problem still appears. See if | |
| // we can eliminate some of the created functions from being candidates. | |
| DisambiguateGlobalSymbols(BD.getProgram()); | |
| // Do the reduction... | |
| if (!BugpointIsInterrupted) | |
| ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions, | |
| Error); | |
| if (!Error.empty()) | |
| return MiscompiledFunctions; | |
| outs() << "\n*** The following function" | |
| << (MiscompiledFunctions.size() == 1 ? " is" : "s are") | |
| << " being miscompiled: "; | |
| PrintFunctionList(MiscompiledFunctions); | |
| outs() << '\n'; | |
| } | |
| } | |
| if (!BugpointIsInterrupted && !DisableBlockExtraction) { | |
| bool Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions, Error); | |
| if (!Error.empty()) | |
| return MiscompiledFunctions; | |
| if (Ret) { | |
| // Okay, we extracted some blocks and the problem still appears. See if | |
| // we can eliminate some of the created functions from being candidates. | |
| DisambiguateGlobalSymbols(BD.getProgram()); | |
| // Do the reduction... | |
| ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions, | |
| Error); | |
| if (!Error.empty()) | |
| return MiscompiledFunctions; | |
| outs() << "\n*** The following function" | |
| << (MiscompiledFunctions.size() == 1 ? " is" : "s are") | |
| << " being miscompiled: "; | |
| PrintFunctionList(MiscompiledFunctions); | |
| outs() << '\n'; | |
| } | |
| } | |
| return MiscompiledFunctions; | |
| } | |
| /// TestOptimizer - This is the predicate function used to check to see if the | |
| /// "Test" portion of the program is misoptimized. If so, return true. In any | |
| /// case, both module arguments are deleted. | |
| /// | |
| static bool TestOptimizer(BugDriver &BD, Module *Test, Module *Safe, | |
| std::string &Error) { | |
| // Run the optimization passes on ToOptimize, producing a transformed version | |
| // of the functions being tested. | |
| outs() << " Optimizing functions being tested: "; | |
| Module *Optimized = BD.runPassesOn(Test, BD.getPassesToRun(), | |
| /*AutoDebugCrashes*/true); | |
| outs() << "done.\n"; | |
| delete Test; | |
| outs() << " Checking to see if the merged program executes correctly: "; | |
| bool Broken; | |
| Module *New = TestMergedProgram(BD, Optimized, Safe, true, Error, Broken); | |
| if (New) { | |
| outs() << (Broken ? " nope.\n" : " yup.\n"); | |
| // Delete the original and set the new program. | |
| delete BD.swapProgramIn(New); | |
| } | |
| return Broken; | |
| } | |
| /// debugMiscompilation - This method is used when the passes selected are not | |
| /// crashing, but the generated output is semantically different from the | |
| /// input. | |
| /// | |
| void BugDriver::debugMiscompilation(std::string *Error) { | |
| // Make sure something was miscompiled... | |
| if (!BugpointIsInterrupted) | |
| if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun, *Error)) { | |
| if (Error->empty()) | |
| errs() << "*** Optimized program matches reference output! No problem" | |
| << " detected...\nbugpoint can't help you with your problem!\n"; | |
| return; | |
| } | |
| outs() << "\n*** Found miscompiling pass" | |
| << (getPassesToRun().size() == 1 ? "" : "es") << ": " | |
| << getPassesString(getPassesToRun()) << '\n'; | |
| EmitProgressBitcode(Program, "passinput"); | |
| std::vector<Function *> MiscompiledFunctions = | |
| DebugAMiscompilation(*this, TestOptimizer, *Error); | |
| if (!Error->empty()) | |
| return; | |
| // Output a bunch of bitcode files for the user... | |
| outs() << "Outputting reduced bitcode files which expose the problem:\n"; | |
| ValueToValueMapTy VMap; | |
| Module *ToNotOptimize = CloneModule(getProgram(), VMap); | |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, | |
| MiscompiledFunctions, | |
| VMap); | |
| outs() << " Non-optimized portion: "; | |
| EmitProgressBitcode(ToNotOptimize, "tonotoptimize", true); | |
| delete ToNotOptimize; // Delete hacked module. | |
| outs() << " Portion that is input to optimizer: "; | |
| EmitProgressBitcode(ToOptimize, "tooptimize"); | |
| delete ToOptimize; // Delete hacked module. | |
| return; | |
| } | |
| /// CleanupAndPrepareModules - Get the specified modules ready for code | |
| /// generator testing. | |
| /// | |
| static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test, | |
| Module *Safe) { | |
| // Clean up the modules, removing extra cruft that we don't need anymore... | |
| Test = BD.performFinalCleanups(Test); | |
| // If we are executing the JIT, we have several nasty issues to take care of. | |
| if (!BD.isExecutingJIT()) return; | |
| // First, if the main function is in the Safe module, we must add a stub to | |
| // the Test module to call into it. Thus, we create a new function `main' | |
| // which just calls the old one. | |
| if (Function *oldMain = Safe->getFunction("main")) | |
| if (!oldMain->isDeclaration()) { | |
| // Rename it | |
| oldMain->setName("llvm_bugpoint_old_main"); | |
| // Create a NEW `main' function with same type in the test module. | |
| Function *newMain = Function::Create(oldMain->getFunctionType(), | |
| GlobalValue::ExternalLinkage, | |
| "main", Test); | |
| // Create an `oldmain' prototype in the test module, which will | |
| // corresponds to the real main function in the same module. | |
| Function *oldMainProto = Function::Create(oldMain->getFunctionType(), | |
| GlobalValue::ExternalLinkage, | |
| oldMain->getName(), Test); | |
| // Set up and remember the argument list for the main function. | |
| std::vector<Value*> args; | |
| for (Function::arg_iterator | |
| I = newMain->arg_begin(), E = newMain->arg_end(), | |
| OI = oldMain->arg_begin(); I != E; ++I, ++OI) { | |
| I->setName(OI->getName()); // Copy argument names from oldMain | |
| args.push_back(I); | |
| } | |
| // Call the old main function and return its result | |
| BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain); | |
| CallInst *call = CallInst::Create(oldMainProto, args, "", BB); | |
| // If the type of old function wasn't void, return value of call | |
| ReturnInst::Create(Safe->getContext(), call, BB); | |
| } | |
| // The second nasty issue we must deal with in the JIT is that the Safe | |
| // module cannot directly reference any functions defined in the test | |
| // module. Instead, we use a JIT API call to dynamically resolve the | |
| // symbol. | |
| // Add the resolver to the Safe module. | |
| // Prototype: void *getPointerToNamedFunction(const char* Name) | |
| Constant *resolverFunc = | |
| Safe->getOrInsertFunction("getPointerToNamedFunction", | |
| Type::getInt8PtrTy(Safe->getContext()), | |
| Type::getInt8PtrTy(Safe->getContext()), | |
| (Type *)0); | |
| // Use the function we just added to get addresses of functions we need. | |
| for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) { | |
| if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc && | |
| !F->isIntrinsic() /* ignore intrinsics */) { | |
| Function *TestFn = Test->getFunction(F->getName()); | |
| // Don't forward functions which are external in the test module too. | |
| if (TestFn && !TestFn->isDeclaration()) { | |
| // 1. Add a string constant with its name to the global file | |
| Constant *InitArray = ConstantArray::get(F->getContext(), F->getName()); | |
| GlobalVariable *funcName = | |
| new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/, | |
| GlobalValue::InternalLinkage, InitArray, | |
| F->getName() + "_name"); | |
| // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an | |
| // sbyte* so it matches the signature of the resolver function. | |
| // GetElementPtr *funcName, ulong 0, ulong 0 | |
| std::vector<Constant*> GEPargs(2, | |
| Constant::getNullValue(Type::getInt32Ty(F->getContext()))); | |
| Value *GEP = ConstantExpr::getGetElementPtr(funcName, GEPargs); | |
| std::vector<Value*> ResolverArgs; | |
| ResolverArgs.push_back(GEP); | |
| // Rewrite uses of F in global initializers, etc. to uses of a wrapper | |
| // function that dynamically resolves the calls to F via our JIT API | |
| if (!F->use_empty()) { | |
| // Create a new global to hold the cached function pointer. | |
| Constant *NullPtr = ConstantPointerNull::get(F->getType()); | |
| GlobalVariable *Cache = | |
| new GlobalVariable(*F->getParent(), F->getType(), | |
| false, GlobalValue::InternalLinkage, | |
| NullPtr,F->getName()+".fpcache"); | |
| // Construct a new stub function that will re-route calls to F | |
| FunctionType *FuncTy = F->getFunctionType(); | |
| Function *FuncWrapper = Function::Create(FuncTy, | |
| GlobalValue::InternalLinkage, | |
| F->getName() + "_wrapper", | |
| F->getParent()); | |
| BasicBlock *EntryBB = BasicBlock::Create(F->getContext(), | |
| "entry", FuncWrapper); | |
| BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(), | |
| "usecache", FuncWrapper); | |
| BasicBlock *LookupBB = BasicBlock::Create(F->getContext(), | |
| "lookupfp", FuncWrapper); | |
| // Check to see if we already looked up the value. | |
| Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB); | |
| Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal, | |
| NullPtr, "isNull"); | |
| BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB); | |
| // Resolve the call to function F via the JIT API: | |
| // | |
| // call resolver(GetElementPtr...) | |
| CallInst *Resolver = | |
| CallInst::Create(resolverFunc, ResolverArgs, "resolver", LookupBB); | |
| // Cast the result from the resolver to correctly-typed function. | |
| CastInst *CastedResolver = | |
| new BitCastInst(Resolver, | |
| PointerType::getUnqual(F->getFunctionType()), | |
| "resolverCast", LookupBB); | |
| // Save the value in our cache. | |
| new StoreInst(CastedResolver, Cache, LookupBB); | |
| BranchInst::Create(DoCallBB, LookupBB); | |
| PHINode *FuncPtr = PHINode::Create(NullPtr->getType(), 2, | |
| "fp", DoCallBB); | |
| FuncPtr->addIncoming(CastedResolver, LookupBB); | |
| FuncPtr->addIncoming(CachedVal, EntryBB); | |
| // Save the argument list. | |
| std::vector<Value*> Args; | |
| for (Function::arg_iterator i = FuncWrapper->arg_begin(), | |
| e = FuncWrapper->arg_end(); i != e; ++i) | |
| Args.push_back(i); | |
| // Pass on the arguments to the real function, return its result | |
| if (F->getReturnType()->isVoidTy()) { | |
| CallInst::Create(FuncPtr, Args, "", DoCallBB); | |
| ReturnInst::Create(F->getContext(), DoCallBB); | |
| } else { | |
| CallInst *Call = CallInst::Create(FuncPtr, Args, | |
| "retval", DoCallBB); | |
| ReturnInst::Create(F->getContext(),Call, DoCallBB); | |
| } | |
| // Use the wrapper function instead of the old function | |
| F->replaceAllUsesWith(FuncWrapper); | |
| } | |
| } | |
| } | |
| } | |
| if (verifyModule(*Test) || verifyModule(*Safe)) { | |
| errs() << "Bugpoint has a bug, which corrupted a module!!\n"; | |
| abort(); | |
| } | |
| } | |
| /// TestCodeGenerator - This is the predicate function used to check to see if | |
| /// the "Test" portion of the program is miscompiled by the code generator under | |
| /// test. If so, return true. In any case, both module arguments are deleted. | |
| /// | |
| static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe, | |
| std::string &Error) { | |
| CleanupAndPrepareModules(BD, Test, Safe); | |
| sys::Path TestModuleBC("bugpoint.test.bc"); | |
| std::string ErrMsg; | |
| if (TestModuleBC.makeUnique(true, &ErrMsg)) { | |
| errs() << BD.getToolName() << "Error making unique filename: " | |
| << ErrMsg << "\n"; | |
| exit(1); | |
| } | |
| if (BD.writeProgramToFile(TestModuleBC.str(), Test)) { | |
| errs() << "Error writing bitcode to `" << TestModuleBC.str() | |
| << "'\nExiting."; | |
| exit(1); | |
| } | |
| delete Test; | |
| FileRemover TestModuleBCRemover(TestModuleBC.str(), !SaveTemps); | |
| // Make the shared library | |
| sys::Path SafeModuleBC("bugpoint.safe.bc"); | |
| if (SafeModuleBC.makeUnique(true, &ErrMsg)) { | |
| errs() << BD.getToolName() << "Error making unique filename: " | |
| << ErrMsg << "\n"; | |
| exit(1); | |
| } | |
| if (BD.writeProgramToFile(SafeModuleBC.str(), Safe)) { | |
| errs() << "Error writing bitcode to `" << SafeModuleBC.str() | |
| << "'\nExiting."; | |
| exit(1); | |
| } | |
| FileRemover SafeModuleBCRemover(SafeModuleBC.str(), !SaveTemps); | |
| std::string SharedObject = BD.compileSharedObject(SafeModuleBC.str(), Error); | |
| if (!Error.empty()) | |
| return false; | |
| delete Safe; | |
| FileRemover SharedObjectRemover(SharedObject, !SaveTemps); | |
| // Run the code generator on the `Test' code, loading the shared library. | |
| // The function returns whether or not the new output differs from reference. | |
| bool Result = BD.diffProgram(BD.getProgram(), TestModuleBC.str(), | |
| SharedObject, false, &Error); | |
| if (!Error.empty()) | |
| return false; | |
| if (Result) | |
| errs() << ": still failing!\n"; | |
| else | |
| errs() << ": didn't fail.\n"; | |
| return Result; | |
| } | |
| /// debugCodeGenerator - debug errors in LLC, LLI, or CBE. | |
| /// | |
| bool BugDriver::debugCodeGenerator(std::string *Error) { | |
| if ((void*)SafeInterpreter == (void*)Interpreter) { | |
| std::string Result = executeProgramSafely(Program, "bugpoint.safe.out", | |
| Error); | |
| if (Error->empty()) { | |
| outs() << "\n*** The \"safe\" i.e. 'known good' backend cannot match " | |
| << "the reference diff. This may be due to a\n front-end " | |
| << "bug or a bug in the original program, but this can also " | |
| << "happen if bugpoint isn't running the program with the " | |
| << "right flags or input.\n I left the result of executing " | |
| << "the program with the \"safe\" backend in this file for " | |
| << "you: '" | |
| << Result << "'.\n"; | |
| } | |
| return true; | |
| } | |
| DisambiguateGlobalSymbols(Program); | |
| std::vector<Function*> Funcs = DebugAMiscompilation(*this, TestCodeGenerator, | |
| *Error); | |
| if (!Error->empty()) | |
| return true; | |
| // Split the module into the two halves of the program we want. | |
| ValueToValueMapTy VMap; | |
| Module *ToNotCodeGen = CloneModule(getProgram(), VMap); | |
| Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, VMap); | |
| // Condition the modules | |
| CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen); | |
| sys::Path TestModuleBC("bugpoint.test.bc"); | |
| std::string ErrMsg; | |
| if (TestModuleBC.makeUnique(true, &ErrMsg)) { | |
| errs() << getToolName() << "Error making unique filename: " | |
| << ErrMsg << "\n"; | |
| exit(1); | |
| } | |
| if (writeProgramToFile(TestModuleBC.str(), ToCodeGen)) { | |
| errs() << "Error writing bitcode to `" << TestModuleBC.str() | |
| << "'\nExiting."; | |
| exit(1); | |
| } | |
| delete ToCodeGen; | |
| // Make the shared library | |
| sys::Path SafeModuleBC("bugpoint.safe.bc"); | |
| if (SafeModuleBC.makeUnique(true, &ErrMsg)) { | |
| errs() << getToolName() << "Error making unique filename: " | |
| << ErrMsg << "\n"; | |
| exit(1); | |
| } | |
| if (writeProgramToFile(SafeModuleBC.str(), ToNotCodeGen)) { | |
| errs() << "Error writing bitcode to `" << SafeModuleBC.str() | |
| << "'\nExiting."; | |
| exit(1); | |
| } | |
| std::string SharedObject = compileSharedObject(SafeModuleBC.str(), *Error); | |
| if (!Error->empty()) | |
| return true; | |
| delete ToNotCodeGen; | |
| outs() << "You can reproduce the problem with the command line: \n"; | |
| if (isExecutingJIT()) { | |
| outs() << " lli -load " << SharedObject << " " << TestModuleBC.str(); | |
| } else { | |
| outs() << " llc " << TestModuleBC.str() << " -o " << TestModuleBC.str() | |
| << ".s\n"; | |
| outs() << " gcc " << SharedObject << " " << TestModuleBC.str() | |
| << ".s -o " << TestModuleBC.str() << ".exe"; | |
| #if defined (HAVE_LINK_R) | |
| outs() << " -Wl,-R."; | |
| #endif | |
| outs() << "\n"; | |
| outs() << " " << TestModuleBC.str() << ".exe"; | |
| } | |
| for (unsigned i = 0, e = InputArgv.size(); i != e; ++i) | |
| outs() << " " << InputArgv[i]; | |
| outs() << '\n'; | |
| outs() << "The shared object was created with:\n llc -march=c " | |
| << SafeModuleBC.str() << " -o temporary.c\n" | |
| << " gcc -xc temporary.c -O2 -o " << SharedObject; | |
| if (TargetTriple.getArch() == Triple::sparc) | |
| outs() << " -G"; // Compile a shared library, `-G' for Sparc | |
| else | |
| outs() << " -fPIC -shared"; // `-shared' for Linux/X86, maybe others | |
| outs() << " -fno-strict-aliasing\n"; | |
| return false; | |
| } |