| //===- 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/Support/Mangler.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::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<const PassInfo*> { |
| BugDriver &BD; |
| public: |
| ReduceMiscompilingPasses(BugDriver &bd) : BD(bd) {} |
| |
| virtual TestResult doTest(std::vector<const PassInfo*> &Prefix, |
| std::vector<const PassInfo*> &Suffix); |
| }; |
| } |
| |
| /// 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<const PassInfo*> &Prefix, |
| std::vector<const PassInfo*> &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(Suffix, BitcodeResult, false/*delete*/, true/*quiet*/)) { |
| errs() << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.setPassesToRun(Suffix); |
| BD.EmitProgressBitcode("pass-error", false); |
| exit(BD.debugOptimizerCrash()); |
| } |
| |
| // Check to see if the finished program matches the reference output... |
| if (BD.diffProgram(BitcodeResult, "", true /*delete bitcode*/)) { |
| 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(Prefix, BitcodeResult, false/*delete*/, true/*quiet*/)) { |
| errs() << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.setPassesToRun(Prefix); |
| BD.EmitProgressBitcode("pass-error", false); |
| exit(BD.debugOptimizerCrash()); |
| } |
| |
| // If the prefix maintains the predicate by itself, only keep the prefix! |
| if (BD.diffProgram(BitcodeResult)) { |
| 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. |
| // |
| 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: "; |
| |
| Module *OriginalInput = BD.swapProgramIn(PrefixOutput); |
| if (BD.runPasses(Suffix, BitcodeResult, false/*delete*/, true/*quiet*/)) { |
| errs() << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.setPassesToRun(Suffix); |
| BD.EmitProgressBitcode("pass-error", false); |
| exit(BD.debugOptimizerCrash()); |
| } |
| |
| // Run the result... |
| if (BD.diffProgram(BitcodeResult, "", true/*delete bitcode*/)) { |
| outs() << " nope.\n"; |
| delete OriginalInput; // We pruned down the original input... |
| return KeepSuffix; |
| } |
| |
| // Otherwise, we must not be running the bad pass anymore. |
| outs() << " yup.\n"; // No miscompilation! |
| delete BD.swapProgramIn(OriginalInput); // Restore orig program & free test |
| return NoFailure; |
| } |
| |
| namespace { |
| class ReduceMiscompilingFunctions : public ListReducer<Function*> { |
| BugDriver &BD; |
| bool (*TestFn)(BugDriver &, Module *, Module *); |
| public: |
| ReduceMiscompilingFunctions(BugDriver &bd, |
| bool (*F)(BugDriver &, Module *, Module *)) |
| : BD(bd), TestFn(F) {} |
| |
| virtual TestResult doTest(std::vector<Function*> &Prefix, |
| std::vector<Function*> &Suffix) { |
| if (!Suffix.empty() && TestFuncs(Suffix)) |
| return KeepSuffix; |
| if (!Prefix.empty() && TestFuncs(Prefix)) |
| return KeepPrefix; |
| return NoFailure; |
| } |
| |
| bool TestFuncs(const std::vector<Function*> &Prefix); |
| }; |
| } |
| |
| /// TestMergedProgram - Given two modules, link them together and run the |
| /// program, checking to see if the program matches the diff. If the diff |
| /// matches, return false, otherwise return true. If the DeleteInputs argument |
| /// is set to true then this function deletes both input modules before it |
| /// returns. |
| /// |
| static bool TestMergedProgram(BugDriver &BD, Module *M1, Module *M2, |
| bool DeleteInputs) { |
| // 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, &ErrorMsg)) { |
| errs() << BD.getToolName() << ": Error linking modules together:" |
| << ErrorMsg << '\n'; |
| exit(1); |
| } |
| delete M2; // We are done with this module. |
| |
| Module *OldProgram = BD.swapProgramIn(M1); |
| |
| // Execute the program. If it does not match the expected output, we must |
| // return true. |
| bool Broken = BD.diffProgram(); |
| |
| // Delete the linked module & restore the original |
| BD.swapProgramIn(OldProgram); |
| delete M1; |
| return Broken; |
| } |
| |
| /// 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){ |
| // 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'; |
| |
| // Split the module into the two halves of the program we want. |
| DenseMap<const Value*, Value*> ValueMap; |
| Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap); |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, Funcs, |
| ValueMap); |
| |
| // Run the predicate, note that the predicate will delete both input modules. |
| return TestFn(BD, ToOptimize, ToNotOptimize); |
| } |
| |
| /// DisambiguateGlobalSymbols - Mangle symbols to guarantee uniqueness by |
| /// modifying predominantly internal symbols rather than external ones. |
| /// |
| static void DisambiguateGlobalSymbols(Module *M) { |
| // Try not to cause collisions by minimizing chances of renaming an |
| // already-external symbol, so take in external globals and functions as-is. |
| // The code should work correctly without disambiguation (assuming the same |
| // mangler is used by the two code generators), but having symbols with the |
| // same name causes warnings to be emitted by the code generator. |
| Mangler Mang(*M); |
| // Agree with the CBE on symbol naming |
| Mang.markCharUnacceptable('.'); |
| for (Module::global_iterator I = M->global_begin(), E = M->global_end(); |
| I != E; ++I) { |
| // Don't mangle asm names. |
| if (!I->hasName() || I->getName()[0] != 1) |
| I->setName(Mang.getMangledName(I)); |
| } |
| for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) { |
| // Don't mangle asm names or intrinsics. |
| if ((!I->hasName() || I->getName()[0] != 1) && |
| I->getIntrinsicID() == 0) |
| I->setName(Mang.getMangledName(I)); |
| } |
| } |
| |
| /// 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::vector<Function*> &MiscompiledFunctions) { |
| bool MadeChange = false; |
| while (1) { |
| if (BugpointIsInterrupted) return MadeChange; |
| |
| DenseMap<const Value*, Value*> ValueMap; |
| Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap); |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, |
| MiscompiledFunctions, |
| ValueMap); |
| 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(); |
| if (TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, false)) { |
| 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("bugpoint-loop-extract-fail-tno.bc", ToNotOptimize); |
| BD.writeProgramToFile("bugpoint-loop-extract-fail-to.bc", ToOptimize); |
| BD.writeProgramToFile("bugpoint-loop-extract-fail-to-le.bc", |
| ToOptimizeLoopExtracted); |
| |
| errs() << "Please submit the bugpoint-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); |
| if (!TestFn(BD, ToOptimizeLoopExtracted, ToNotOptimize)) { |
| 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, const 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, &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??"); |
| assert(NewF->getFunctionType() == MisCompFunctions[i].second && |
| "found wrong function type?"); |
| MiscompiledFunctions.push_back(NewF); |
| } |
| |
| BD.setNewProgram(ToNotOptimize); |
| MadeChange = true; |
| } |
| } |
| |
| namespace { |
| class ReduceMiscompiledBlocks : public ListReducer<BasicBlock*> { |
| BugDriver &BD; |
| bool (*TestFn)(BugDriver &, Module *, Module *); |
| std::vector<Function*> FunctionsBeingTested; |
| public: |
| ReduceMiscompiledBlocks(BugDriver &bd, |
| bool (*F)(BugDriver &, Module *, Module *), |
| const std::vector<Function*> &Fns) |
| : BD(bd), TestFn(F), FunctionsBeingTested(Fns) {} |
| |
| virtual TestResult doTest(std::vector<BasicBlock*> &Prefix, |
| std::vector<BasicBlock*> &Suffix) { |
| if (!Suffix.empty() && TestFuncs(Suffix)) |
| return KeepSuffix; |
| if (TestFuncs(Prefix)) |
| return KeepPrefix; |
| return NoFailure; |
| } |
| |
| bool TestFuncs(const std::vector<BasicBlock*> &Prefix); |
| }; |
| } |
| |
| /// 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) { |
| // 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. |
| DenseMap<const Value*, Value*> ValueMap; |
| Module *ToNotOptimize = CloneModule(BD.getProgram(), ValueMap); |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, |
| FunctionsBeingTested, |
| ValueMap); |
| |
| // 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(BBs, ToOptimize)) { |
| delete ToOptimize; |
| // Run the predicate, not that the predicate will delete both input modules. |
| return TestFn(BD, New, ToNotOptimize); |
| } |
| 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::vector<Function*> &MiscompiledFunctions) { |
| 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. |
| if (ReduceMiscompiledBlocks(BD, TestFn, |
| MiscompiledFunctions).TestFuncs(std::vector<BasicBlock*>())) { |
| Blocks.clear(); |
| } else { |
| ReduceMiscompiledBlocks(BD, TestFn,MiscompiledFunctions).reduceList(Blocks); |
| if (Blocks.size() == OldSize) |
| return false; |
| } |
| |
| DenseMap<const Value*, Value*> ValueMap; |
| Module *ProgClone = CloneModule(BD.getProgram(), ValueMap); |
| Module *ToExtract = SplitFunctionsOutOfModule(ProgClone, |
| MiscompiledFunctions, |
| ValueMap); |
| 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, const 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, &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??"); |
| assert(NewF->getFunctionType() == MisCompFunctions[i].second && |
| "Function has wrong type??"); |
| 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 *)) { |
| // 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); |
| |
| 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 && |
| ExtractLoops(BD, TestFn, MiscompiledFunctions)) { |
| // Okay, we extracted some loops and the problem still appears. See if we |
| // can eliminate some of the created functions from being candidates. |
| |
| // Loop extraction can introduce functions with the same name (foo_code). |
| // Make sure to disambiguate the symbols so that when the program is split |
| // apart that we can link it back together again. |
| DisambiguateGlobalSymbols(BD.getProgram()); |
| |
| // Do the reduction... |
| if (!BugpointIsInterrupted) |
| ReduceMiscompilingFunctions(BD, TestFn).reduceList(MiscompiledFunctions); |
| |
| outs() << "\n*** The following function" |
| << (MiscompiledFunctions.size() == 1 ? " is" : "s are") |
| << " being miscompiled: "; |
| PrintFunctionList(MiscompiledFunctions); |
| outs() << '\n'; |
| } |
| |
| if (!BugpointIsInterrupted && !DisableBlockExtraction && |
| ExtractBlocks(BD, TestFn, MiscompiledFunctions)) { |
| // Okay, we extracted some blocks and the problem still appears. See if we |
| // can eliminate some of the created functions from being candidates. |
| |
| // Block extraction can introduce functions with the same name (foo_code). |
| // Make sure to disambiguate the symbols so that when the program is split |
| // apart that we can link it back together again. |
| DisambiguateGlobalSymbols(BD.getProgram()); |
| |
| // Do the reduction... |
| ReduceMiscompilingFunctions(BD, TestFn).reduceList(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) { |
| // 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 = TestMergedProgram(BD, Optimized, Safe, true); |
| outs() << (Broken ? " nope.\n" : " yup.\n"); |
| return Broken; |
| } |
| |
| |
| /// debugMiscompilation - This method is used when the passes selected are not |
| /// crashing, but the generated output is semantically different from the |
| /// input. |
| /// |
| bool BugDriver::debugMiscompilation() { |
| // Make sure something was miscompiled... |
| if (!BugpointIsInterrupted) |
| if (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun)) { |
| errs() << "*** Optimized program matches reference output! No problem" |
| << " detected...\nbugpoint can't help you with your problem!\n"; |
| return false; |
| } |
| |
| outs() << "\n*** Found miscompiling pass" |
| << (getPassesToRun().size() == 1 ? "" : "es") << ": " |
| << getPassesString(getPassesToRun()) << '\n'; |
| EmitProgressBitcode("passinput"); |
| |
| std::vector<Function*> MiscompiledFunctions = |
| DebugAMiscompilation(*this, TestOptimizer); |
| |
| // Output a bunch of bitcode files for the user... |
| outs() << "Outputting reduced bitcode files which expose the problem:\n"; |
| DenseMap<const Value*, Value*> ValueMap; |
| Module *ToNotOptimize = CloneModule(getProgram(), ValueMap); |
| Module *ToOptimize = SplitFunctionsOutOfModule(ToNotOptimize, |
| MiscompiledFunctions, |
| ValueMap); |
| |
| outs() << " Non-optimized portion: "; |
| ToNotOptimize = swapProgramIn(ToNotOptimize); |
| EmitProgressBitcode("tonotoptimize", true); |
| setNewProgram(ToNotOptimize); // Delete hacked module. |
| |
| outs() << " Portion that is input to optimizer: "; |
| ToOptimize = swapProgramIn(ToOptimize); |
| EmitProgressBitcode("tooptimize"); |
| setNewProgram(ToOptimize); // Delete hacked module. |
| |
| return false; |
| } |
| |
| /// 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.begin(), args.end(), |
| "", 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", |
| PointerType::getUnqual(Type::getInt8Ty(Safe->getContext())), |
| PointerType::getUnqual(Type::getInt8Ty(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[0], 2); |
| 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 |
| const 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.begin(), |
| ResolverArgs.end(), "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(), |
| "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() == Type::getVoidTy(F->getContext())) { |
| CallInst::Create(FuncPtr, Args.begin(), Args.end(), "", DoCallBB); |
| ReturnInst::Create(F->getContext(), DoCallBB); |
| } else { |
| CallInst *Call = CallInst::Create(FuncPtr, Args.begin(), Args.end(), |
| "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) { |
| 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.toString(), Test)) { |
| errs() << "Error writing bitcode to `" << TestModuleBC << "'\nExiting."; |
| exit(1); |
| } |
| delete Test; |
| |
| // 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.toString(), Safe)) { |
| errs() << "Error writing bitcode to `" << SafeModuleBC << "'\nExiting."; |
| exit(1); |
| } |
| std::string SharedObject = BD.compileSharedObject(SafeModuleBC.toString()); |
| delete Safe; |
| |
| // Run the code generator on the `Test' code, loading the shared library. |
| // The function returns whether or not the new output differs from reference. |
| int Result = BD.diffProgram(TestModuleBC.toString(), SharedObject, false); |
| |
| if (Result) |
| errs() << ": still failing!\n"; |
| else |
| errs() << ": didn't fail.\n"; |
| TestModuleBC.eraseFromDisk(); |
| SafeModuleBC.eraseFromDisk(); |
| sys::Path(SharedObject).eraseFromDisk(); |
| |
| return Result; |
| } |
| |
| |
| /// debugCodeGenerator - debug errors in LLC, LLI, or CBE. |
| /// |
| bool BugDriver::debugCodeGenerator() { |
| if ((void*)SafeInterpreter == (void*)Interpreter) { |
| std::string Result = executeProgramSafely("bugpoint.safe.out"); |
| 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); |
| |
| // Split the module into the two halves of the program we want. |
| DenseMap<const Value*, Value*> ValueMap; |
| Module *ToNotCodeGen = CloneModule(getProgram(), ValueMap); |
| Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs, ValueMap); |
| |
| // 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.toString(), ToCodeGen)) { |
| errs() << "Error writing bitcode to `" << TestModuleBC << "'\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.toString(), ToNotCodeGen)) { |
| errs() << "Error writing bitcode to `" << SafeModuleBC << "'\nExiting."; |
| exit(1); |
| } |
| std::string SharedObject = compileSharedObject(SafeModuleBC.toString()); |
| delete ToNotCodeGen; |
| |
| outs() << "You can reproduce the problem with the command line: \n"; |
| if (isExecutingJIT()) { |
| outs() << " lli -load " << SharedObject << " " << TestModuleBC; |
| } else { |
| outs() << " llc -f " << TestModuleBC << " -o " << TestModuleBC<< ".s\n"; |
| outs() << " gcc " << SharedObject << " " << TestModuleBC |
| << ".s -o " << TestModuleBC << ".exe"; |
| #if defined (HAVE_LINK_R) |
| outs() << " -Wl,-R."; |
| #endif |
| outs() << "\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 << " -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; |
| } |
