| //===- 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/Config/config.h" // for HAVE_LINK_R |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Instructions.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/Verifier.h" |
| #include "llvm/Linker/Linker.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/FileUtilities.h" |
| #include "llvm/Transforms/Utils/Cloning.h" |
| |
| using namespace llvm; |
| |
| namespace llvm { |
| extern cl::opt<std::string> OutputPrefix; |
| extern cl::list<std::string> InputArgv; |
| } // end namespace llvm |
| |
| 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) {} |
| |
| Expected<TestResult> doTest(std::vector<std::string> &Prefix, |
| std::vector<std::string> &Suffix) override; |
| }; |
| } // end anonymous namespace |
| |
| /// TestResult - After passes have been split into a test group and a control |
| /// group, see if they still break the program. |
| /// |
| Expected<ReduceMiscompilingPasses::TestResult> |
| ReduceMiscompilingPasses::doTest(std::vector<std::string> &Prefix, |
| std::vector<std::string> &Suffix) { |
| // 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); |
| // TODO: This should propagate the error instead of exiting. |
| if (Error E = BD.debugOptimizerCrash()) |
| exit(1); |
| exit(0); |
| } |
| |
| // Check to see if the finished program matches the reference output... |
| Expected<bool> Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", |
| true /*delete bitcode*/); |
| if (Error E = Diff.takeError()) |
| return std::move(E); |
| 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); |
| // TODO: This should propagate the error instead of exiting. |
| if (Error E = BD.debugOptimizerCrash()) |
| exit(1); |
| exit(0); |
| } |
| |
| // If the prefix maintains the predicate by itself, only keep the prefix! |
| Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", false); |
| if (Error E = Diff.takeError()) |
| return std::move(E); |
| if (*Diff) { |
| outs() << " nope.\n"; |
| sys::fs::remove(BitcodeResult); |
| 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. |
| // |
| std::unique_ptr<Module> PrefixOutput = |
| parseInputFile(BitcodeResult, BD.getContext()); |
| if (!PrefixOutput) { |
| errs() << BD.getToolName() << ": Error reading bitcode file '" |
| << BitcodeResult << "'!\n"; |
| exit(1); |
| } |
| sys::fs::remove(BitcodeResult); |
| |
| // 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: "; |
| |
| std::unique_ptr<Module> OriginalInput = |
| BD.swapProgramIn(std::move(PrefixOutput)); |
| 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); |
| // TODO: This should propagate the error instead of exiting. |
| if (Error E = BD.debugOptimizerCrash()) |
| exit(1); |
| exit(0); |
| } |
| |
| // Run the result... |
| Diff = BD.diffProgram(BD.getProgram(), BitcodeResult, "", |
| true /*delete bitcode*/); |
| if (Error E = Diff.takeError()) |
| return std::move(E); |
| 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. |
| BD.setNewProgram(std::move(OriginalInput)); |
| return NoFailure; |
| } |
| |
| namespace { |
| class ReduceMiscompilingFunctions : public ListReducer<Function *> { |
| BugDriver &BD; |
| Expected<bool> (*TestFn)(BugDriver &, std::unique_ptr<Module>, |
| std::unique_ptr<Module>); |
| |
| public: |
| ReduceMiscompilingFunctions(BugDriver &bd, |
| Expected<bool> (*F)(BugDriver &, |
| std::unique_ptr<Module>, |
| std::unique_ptr<Module>)) |
| : BD(bd), TestFn(F) {} |
| |
| Expected<TestResult> doTest(std::vector<Function *> &Prefix, |
| std::vector<Function *> &Suffix) override { |
| if (!Suffix.empty()) { |
| Expected<bool> Ret = TestFuncs(Suffix); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| if (*Ret) |
| return KeepSuffix; |
| } |
| if (!Prefix.empty()) { |
| Expected<bool> Ret = TestFuncs(Prefix); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| if (*Ret) |
| return KeepPrefix; |
| } |
| return NoFailure; |
| } |
| |
| Expected<bool> TestFuncs(const std::vector<Function *> &Prefix); |
| }; |
| } // end anonymous namespace |
| |
| /// 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 Expected<std::unique_ptr<Module>> testMergedProgram(const BugDriver &BD, |
| const Module &M1, |
| const Module &M2, |
| bool &Broken) { |
| // Resulting merge of M1 and M2. |
| auto Merged = CloneModule(M1); |
| if (Linker::linkModules(*Merged, CloneModule(M2))) |
| // TODO: Shouldn't we thread the error up instead of exiting? |
| exit(1); |
| |
| // Execute the program. |
| Expected<bool> Diff = BD.diffProgram(*Merged, "", "", false); |
| if (Error E = Diff.takeError()) |
| return std::move(E); |
| Broken = *Diff; |
| return std::move(Merged); |
| } |
| |
| /// 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. |
| Expected<bool> |
| ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function *> &Funcs) { |
| // 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; |
| std::unique_ptr<Module> Clone = CloneModule(BD.getProgram(), VMap); |
| std::unique_ptr<Module> Orig = BD.swapProgramIn(std::move(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(); |
| std::unique_ptr<Module> ToNotOptimize = CloneModule(BD.getProgram(), VMap); |
| std::unique_ptr<Module> ToOptimize = |
| SplitFunctionsOutOfModule(ToNotOptimize.get(), FuncsOnClone, VMap); |
| |
| Expected<bool> Broken = |
| TestFn(BD, std::move(ToOptimize), std::move(ToNotOptimize)); |
| |
| BD.setNewProgram(std::move(Orig)); |
| |
| return Broken; |
| } |
| |
| /// 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"); |
| } |
| |
| /// 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 Expected<bool> |
| ExtractLoops(BugDriver &BD, |
| Expected<bool> (*TestFn)(BugDriver &, std::unique_ptr<Module>, |
| std::unique_ptr<Module>), |
| std::vector<Function *> &MiscompiledFunctions) { |
| bool MadeChange = false; |
| while (1) { |
| if (BugpointIsInterrupted) |
| return MadeChange; |
| |
| ValueToValueMapTy VMap; |
| std::unique_ptr<Module> ToNotOptimize = CloneModule(BD.getProgram(), VMap); |
| std::unique_ptr<Module> ToOptimize = SplitFunctionsOutOfModule( |
| ToNotOptimize.get(), MiscompiledFunctions, VMap); |
| std::unique_ptr<Module> ToOptimizeLoopExtracted = |
| BD.extractLoop(ToOptimize.get()); |
| if (!ToOptimizeLoopExtracted) |
| // If the loop extractor crashed or if there were no extractible loops, |
| // then this chapter of our odyssey is over with. |
| 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; |
| Expected<std::unique_ptr<Module>> New = testMergedProgram( |
| BD, *ToOptimizeLoopExtracted, *ToNotOptimize, Failure); |
| if (Error E = New.takeError()) |
| return std::move(E); |
| if (!*New) |
| return false; |
| |
| // Delete the original and set the new program. |
| std::unique_ptr<Module> Old = BD.swapProgramIn(std::move(*New)); |
| for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) |
| MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]); |
| |
| 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"; |
| return MadeChange; |
| } |
| BD.switchToInterpreter(AI); |
| |
| outs() << " Testing after loop extraction:\n"; |
| // Clone modules, the tester function will free them. |
| std::unique_ptr<Module> TOLEBackup = |
| CloneModule(*ToOptimizeLoopExtracted, VMap); |
| std::unique_ptr<Module> TNOBackup = CloneModule(*ToNotOptimize, VMap); |
| |
| for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) |
| MiscompiledFunctions[i] = cast<Function>(VMap[MiscompiledFunctions[i]]); |
| |
| Expected<bool> Result = TestFn(BD, std::move(ToOptimizeLoopExtracted), |
| std::move(ToNotOptimize)); |
| if (Error E = Result.takeError()) |
| return std::move(E); |
| |
| ToOptimizeLoopExtracted = std::move(TOLEBackup); |
| ToNotOptimize = std::move(TNOBackup); |
| |
| if (!*Result) { |
| 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. |
| |
| std::vector<std::pair<std::string, FunctionType *>> MisCompFunctions; |
| for (Function *F : MiscompiledFunctions) { |
| MisCompFunctions.emplace_back(F->getName(), F->getFunctionType()); |
| } |
| |
| if (Linker::linkModules(*ToNotOptimize, |
| std::move(ToOptimizeLoopExtracted))) |
| exit(1); |
| |
| 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(std::move(ToNotOptimize)); |
| return MadeChange; |
| } |
| |
| 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.emplace_back(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. |
| if (Linker::linkModules(*ToNotOptimize, std::move(ToOptimizeLoopExtracted))) |
| exit(1); |
| |
| // 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(std::move(ToNotOptimize)); |
| MadeChange = true; |
| } |
| } |
| |
| namespace { |
| class ReduceMiscompiledBlocks : public ListReducer<BasicBlock *> { |
| BugDriver &BD; |
| Expected<bool> (*TestFn)(BugDriver &, std::unique_ptr<Module>, |
| std::unique_ptr<Module>); |
| std::vector<Function *> FunctionsBeingTested; |
| |
| public: |
| ReduceMiscompiledBlocks(BugDriver &bd, |
| Expected<bool> (*F)(BugDriver &, |
| std::unique_ptr<Module>, |
| std::unique_ptr<Module>), |
| const std::vector<Function *> &Fns) |
| : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {} |
| |
| Expected<TestResult> doTest(std::vector<BasicBlock *> &Prefix, |
| std::vector<BasicBlock *> &Suffix) override { |
| if (!Suffix.empty()) { |
| Expected<bool> Ret = TestFuncs(Suffix); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| if (*Ret) |
| return KeepSuffix; |
| } |
| if (!Prefix.empty()) { |
| Expected<bool> Ret = TestFuncs(Prefix); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| if (*Ret) |
| return KeepPrefix; |
| } |
| return NoFailure; |
| } |
| |
| Expected<bool> TestFuncs(const std::vector<BasicBlock *> &BBs); |
| }; |
| } // end anonymous namespace |
| |
| /// TestFuncs - Extract all blocks for the miscompiled functions except for the |
| /// specified blocks. If the problem still exists, return true. |
| /// |
| Expected<bool> |
| ReduceMiscompiledBlocks::TestFuncs(const std::vector<BasicBlock *> &BBs) { |
| // 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; |
| std::unique_ptr<Module> Clone = CloneModule(BD.getProgram(), VMap); |
| std::unique_ptr<Module> Orig = BD.swapProgramIn(std::move(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(); |
| |
| std::unique_ptr<Module> ToNotOptimize = CloneModule(BD.getProgram(), VMap); |
| std::unique_ptr<Module> ToOptimize = |
| SplitFunctionsOutOfModule(ToNotOptimize.get(), 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 (std::unique_ptr<Module> New = |
| BD.extractMappedBlocksFromModule(BBsOnClone, ToOptimize.get())) { |
| Expected<bool> Ret = TestFn(BD, std::move(New), std::move(ToNotOptimize)); |
| BD.setNewProgram(std::move(Orig)); |
| return Ret; |
| } |
| BD.setNewProgram(std::move(Orig)); |
| return false; |
| } |
| |
| /// 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 Expected<bool> |
| ExtractBlocks(BugDriver &BD, |
| Expected<bool> (*TestFn)(BugDriver &, std::unique_ptr<Module>, |
| std::unique_ptr<Module>), |
| std::vector<Function *> &MiscompiledFunctions) { |
| if (BugpointIsInterrupted) |
| return false; |
| |
| std::vector<BasicBlock *> Blocks; |
| for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) |
| for (BasicBlock &BB : *MiscompiledFunctions[i]) |
| Blocks.push_back(&BB); |
| |
| // 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. |
| Expected<bool> Ret = ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions) |
| .TestFuncs(std::vector<BasicBlock *>()); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| if (*Ret) { |
| Blocks.clear(); |
| } else { |
| Expected<bool> Ret = |
| ReduceMiscompiledBlocks(BD, TestFn, MiscompiledFunctions) |
| .reduceList(Blocks); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| if (Blocks.size() == OldSize) |
| return false; |
| } |
| |
| ValueToValueMapTy VMap; |
| std::unique_ptr<Module> ProgClone = CloneModule(BD.getProgram(), VMap); |
| std::unique_ptr<Module> ToExtract = |
| SplitFunctionsOutOfModule(ProgClone.get(), MiscompiledFunctions, VMap); |
| std::unique_ptr<Module> Extracted = |
| BD.extractMappedBlocksFromModule(Blocks, ToExtract.get()); |
| if (!Extracted) { |
| // Weird, extraction should have worked. |
| errs() << "Nondeterministic problem extracting blocks??\n"; |
| return false; |
| } |
| |
| // Otherwise, block extraction succeeded. Link the two program fragments back |
| // together. |
| |
| std::vector<std::pair<std::string, FunctionType *>> MisCompFunctions; |
| for (Module::iterator I = Extracted->begin(), E = Extracted->end(); I != E; |
| ++I) |
| if (!I->isDeclaration()) |
| MisCompFunctions.emplace_back(I->getName(), I->getFunctionType()); |
| |
| if (Linker::linkModules(*ProgClone, std::move(Extracted))) |
| exit(1); |
| |
| // Set the new program and delete the old one. |
| BD.setNewProgram(std::move(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; |
| } |
| |
| /// This is a generic driver to narrow down miscompilations, either in an |
| /// optimization or a code generator. |
| /// |
| static Expected<std::vector<Function *>> DebugAMiscompilation( |
| BugDriver &BD, |
| Expected<bool> (*TestFn)(BugDriver &, std::unique_ptr<Module>, |
| std::unique_ptr<Module>)) { |
| // 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 (Function &F : Prog) |
| if (!F.isDeclaration()) |
| MiscompiledFunctions.push_back(&F); |
| |
| // Do the reduction... |
| if (!BugpointIsInterrupted) { |
| Expected<bool> Ret = ReduceMiscompilingFunctions(BD, TestFn) |
| .reduceList(MiscompiledFunctions); |
| if (Error E = Ret.takeError()) { |
| errs() << "\n***Cannot reduce functions: "; |
| return std::move(E); |
| } |
| } |
| 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) { |
| Expected<bool> Ret = ExtractLoops(BD, TestFn, MiscompiledFunctions); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| 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) |
| Ret = ReduceMiscompilingFunctions(BD, TestFn) |
| .reduceList(MiscompiledFunctions); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| |
| outs() << "\n*** The following function" |
| << (MiscompiledFunctions.size() == 1 ? " is" : "s are") |
| << " being miscompiled: "; |
| PrintFunctionList(MiscompiledFunctions); |
| outs() << '\n'; |
| } |
| } |
| |
| if (!BugpointIsInterrupted && !DisableBlockExtraction) { |
| Expected<bool> Ret = ExtractBlocks(BD, TestFn, MiscompiledFunctions); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| 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... |
| Ret = ReduceMiscompilingFunctions(BD, TestFn) |
| .reduceList(MiscompiledFunctions); |
| if (Error E = Ret.takeError()) |
| return std::move(E); |
| |
| outs() << "\n*** The following function" |
| << (MiscompiledFunctions.size() == 1 ? " is" : "s are") |
| << " being miscompiled: "; |
| PrintFunctionList(MiscompiledFunctions); |
| outs() << '\n'; |
| } |
| } |
| |
| return MiscompiledFunctions; |
| } |
| |
| /// 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 Expected<bool> TestOptimizer(BugDriver &BD, std::unique_ptr<Module> Test, |
| std::unique_ptr<Module> Safe) { |
| // Run the optimization passes on ToOptimize, producing a transformed version |
| // of the functions being tested. |
| outs() << " Optimizing functions being tested: "; |
| std::unique_ptr<Module> Optimized = |
| BD.runPassesOn(Test.get(), BD.getPassesToRun()); |
| if (!Optimized) { |
| errs() << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.setNewProgram(std::move(Test)); |
| BD.EmitProgressBitcode(*Test, "pass-error", false); |
| if (Error E = BD.debugOptimizerCrash()) |
| return std::move(E); |
| return false; |
| } |
| outs() << "done.\n"; |
| |
| outs() << " Checking to see if the merged program executes correctly: "; |
| bool Broken; |
| auto Result = testMergedProgram(BD, *Optimized, *Safe, Broken); |
| if (Error E = Result.takeError()) |
| return std::move(E); |
| if (auto New = std::move(*Result)) { |
| outs() << (Broken ? " nope.\n" : " yup.\n"); |
| // Delete the original and set the new program. |
| BD.setNewProgram(std::move(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. |
| /// |
| Error BugDriver::debugMiscompilation() { |
| // Make sure something was miscompiled... |
| if (!BugpointIsInterrupted) { |
| Expected<bool> Result = |
| ReduceMiscompilingPasses(*this).reduceList(PassesToRun); |
| if (Error E = Result.takeError()) |
| return E; |
| if (!*Result) |
| return make_error<StringError>( |
| "*** Optimized program matches reference output! No problem" |
| " detected...\nbugpoint can't help you with your problem!\n", |
| inconvertibleErrorCode()); |
| } |
| |
| outs() << "\n*** Found miscompiling pass" |
| << (getPassesToRun().size() == 1 ? "" : "es") << ": " |
| << getPassesString(getPassesToRun()) << '\n'; |
| EmitProgressBitcode(*Program, "passinput"); |
| |
| Expected<std::vector<Function *>> MiscompiledFunctions = |
| DebugAMiscompilation(*this, TestOptimizer); |
| if (Error E = MiscompiledFunctions.takeError()) |
| return E; |
| |
| // 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).release(); |
| Module *ToOptimize = |
| SplitFunctionsOutOfModule(ToNotOptimize, *MiscompiledFunctions, VMap) |
| .release(); |
| |
| 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 Error::success(); |
| } |
| |
| /// Get the specified modules ready for code generator testing. |
| /// |
| static std::unique_ptr<Module> |
| CleanupAndPrepareModules(BugDriver &BD, std::unique_ptr<Module> Test, |
| Module *Safe) { |
| // Clean up the modules, removing extra cruft that we don't need anymore... |
| Test = BD.performFinalCleanups(std::move(Test)); |
| |
| // If we are executing the JIT, we have several nasty issues to take care of. |
| if (!BD.isExecutingJIT()) |
| return Test; |
| |
| // 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.get()); |
| // 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.get()); |
| // 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())); |
| |
| // 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 = |
| ConstantDataArray::getString(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(InitArray->getType(), |
| 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 (Argument &A : FuncWrapper->args()) |
| Args.push_back(&A); |
| |
| // 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(); |
| } |
| |
| return Test; |
| } |
| |
| /// 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 Expected<bool> TestCodeGenerator(BugDriver &BD, |
| std::unique_ptr<Module> Test, |
| std::unique_ptr<Module> Safe) { |
| Test = CleanupAndPrepareModules(BD, std::move(Test), Safe.get()); |
| |
| SmallString<128> TestModuleBC; |
| int TestModuleFD; |
| std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc", |
| TestModuleFD, TestModuleBC); |
| if (EC) { |
| errs() << BD.getToolName() |
| << "Error making unique filename: " << EC.message() << "\n"; |
| exit(1); |
| } |
| if (BD.writeProgramToFile(TestModuleBC.str(), TestModuleFD, *Test)) { |
| errs() << "Error writing bitcode to `" << TestModuleBC.str() |
| << "'\nExiting."; |
| exit(1); |
| } |
| |
| FileRemover TestModuleBCRemover(TestModuleBC.str(), !SaveTemps); |
| |
| // Make the shared library |
| SmallString<128> SafeModuleBC; |
| int SafeModuleFD; |
| EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD, |
| SafeModuleBC); |
| if (EC) { |
| errs() << BD.getToolName() |
| << "Error making unique filename: " << EC.message() << "\n"; |
| exit(1); |
| } |
| |
| if (BD.writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, *Safe)) { |
| errs() << "Error writing bitcode to `" << SafeModuleBC << "'\nExiting."; |
| exit(1); |
| } |
| |
| FileRemover SafeModuleBCRemover(SafeModuleBC.str(), !SaveTemps); |
| |
| Expected<std::string> SharedObject = |
| BD.compileSharedObject(SafeModuleBC.str()); |
| if (Error E = SharedObject.takeError()) |
| return std::move(E); |
| |
| 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. |
| Expected<bool> Result = |
| BD.diffProgram(BD.getProgram(), TestModuleBC.str(), *SharedObject, false); |
| if (Error E = Result.takeError()) |
| return std::move(E); |
| |
| if (*Result) |
| errs() << ": still failing!\n"; |
| else |
| errs() << ": didn't fail.\n"; |
| |
| return Result; |
| } |
| |
| /// debugCodeGenerator - debug errors in LLC, LLI, or CBE. |
| /// |
| Error BugDriver::debugCodeGenerator() { |
| if ((void *)SafeInterpreter == (void *)Interpreter) { |
| Expected<std::string> Result = |
| executeProgramSafely(*Program, "bugpoint.safe.out"); |
| if (Result) { |
| 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 Error::success(); |
| } |
| |
| DisambiguateGlobalSymbols(*Program); |
| |
| Expected<std::vector<Function *>> Funcs = |
| DebugAMiscompilation(*this, TestCodeGenerator); |
| if (Error E = Funcs.takeError()) |
| return E; |
| |
| // Split the module into the two halves of the program we want. |
| ValueToValueMapTy VMap; |
| std::unique_ptr<Module> ToNotCodeGen = CloneModule(getProgram(), VMap); |
| std::unique_ptr<Module> ToCodeGen = |
| SplitFunctionsOutOfModule(ToNotCodeGen.get(), *Funcs, VMap); |
| |
| // Condition the modules |
| ToCodeGen = |
| CleanupAndPrepareModules(*this, std::move(ToCodeGen), ToNotCodeGen.get()); |
| |
| SmallString<128> TestModuleBC; |
| int TestModuleFD; |
| std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc", |
| TestModuleFD, TestModuleBC); |
| if (EC) { |
| errs() << getToolName() << "Error making unique filename: " << EC.message() |
| << "\n"; |
| exit(1); |
| } |
| |
| if (writeProgramToFile(TestModuleBC.str(), TestModuleFD, *ToCodeGen)) { |
| errs() << "Error writing bitcode to `" << TestModuleBC << "'\nExiting."; |
| exit(1); |
| } |
| |
| // Make the shared library |
| SmallString<128> SafeModuleBC; |
| int SafeModuleFD; |
| EC = sys::fs::createTemporaryFile("bugpoint.safe", "bc", SafeModuleFD, |
| SafeModuleBC); |
| if (EC) { |
| errs() << getToolName() << "Error making unique filename: " << EC.message() |
| << "\n"; |
| exit(1); |
| } |
| |
| if (writeProgramToFile(SafeModuleBC.str(), SafeModuleFD, *ToNotCodeGen)) { |
| errs() << "Error writing bitcode to `" << SafeModuleBC << "'\nExiting."; |
| exit(1); |
| } |
| Expected<std::string> SharedObject = compileSharedObject(SafeModuleBC.str()); |
| if (Error E = SharedObject.takeError()) |
| return E; |
| |
| outs() << "You can reproduce the problem with the command line: \n"; |
| if (isExecutingJIT()) { |
| outs() << " lli -load " << *SharedObject << " " << TestModuleBC; |
| } else { |
| outs() << " llc " << TestModuleBC << " -o " << TestModuleBC << ".s\n"; |
| outs() << " cc " << *SharedObject << " " << TestModuleBC.str() << ".s -o " |
| << TestModuleBC << ".exe\n"; |
| outs() << " ./" << TestModuleBC << ".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" |
| << " cc -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 Error::success(); |
| } |
