| //===- Miscompilation.cpp - Debug program miscompilations -----------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements program miscompilation debugging support. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "BugDriver.h" |
| #include "ListReducer.h" |
| #include "llvm/Module.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Transforms/Utils/Cloning.h" |
| #include "llvm/Transforms/Utils/Linker.h" |
| #include "Support/FileUtilities.h" |
| |
| namespace llvm { |
| |
| 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); |
| }; |
| |
| 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. |
| std::cout << "Checking to see if '" << getPassesString(Suffix) |
| << "' compile correctly: "; |
| |
| std::string BytecodeResult; |
| if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) { |
| std::cerr << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.setPassesToRun(Suffix); |
| BD.EmitProgressBytecode("pass-error", false); |
| exit(BD.debugCrash()); |
| } |
| |
| // Check to see if the finished program matches the reference output... |
| if (BD.diffProgram(BytecodeResult, "", true /*delete bytecode*/)) { |
| std::cout << "nope.\n"; |
| return KeepSuffix; // Miscompilation detected! |
| } |
| std::cout << "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. |
| std::cout << "Checking to see if '" << getPassesString(Prefix) |
| << "' compile 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 bytecode file to include the result of the |
| // prefix passes, then discard the prefix passes. |
| // |
| if (BD.runPasses(Prefix, BytecodeResult, false/*delete*/, true/*quiet*/)) { |
| std::cerr << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.setPassesToRun(Prefix); |
| BD.EmitProgressBytecode("pass-error", false); |
| exit(BD.debugCrash()); |
| } |
| |
| // If the prefix maintains the predicate by itself, only keep the prefix! |
| if (BD.diffProgram(BytecodeResult)) { |
| std::cout << "nope.\n"; |
| removeFile(BytecodeResult); |
| return KeepPrefix; |
| } |
| std::cout << "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 = BD.ParseInputFile(BytecodeResult); |
| if (PrefixOutput == 0) { |
| std::cerr << BD.getToolName() << ": Error reading bytecode file '" |
| << BytecodeResult << "'!\n"; |
| exit(1); |
| } |
| removeFile(BytecodeResult); // No longer need the file on disk |
| |
| std::cout << "Checking to see if '" << getPassesString(Suffix) |
| << "' passes compile correctly after the '" |
| << getPassesString(Prefix) << "' passes: "; |
| |
| Module *OriginalInput = BD.Program; |
| BD.Program = PrefixOutput; |
| if (BD.runPasses(Suffix, BytecodeResult, false/*delete*/, true/*quiet*/)) { |
| std::cerr << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.setPassesToRun(Suffix); |
| BD.EmitProgressBytecode("pass-error", false); |
| exit(BD.debugCrash()); |
| } |
| |
| // Run the result... |
| if (BD.diffProgram(BytecodeResult, "", true/*delete bytecode*/)) { |
| std::cout << "nope.\n"; |
| delete OriginalInput; // We pruned down the original input... |
| return KeepSuffix; |
| } |
| |
| // Otherwise, we must not be running the bad pass anymore. |
| std::cout << "yup.\n"; // No miscompilation! |
| BD.Program = OriginalInput; // Restore original program |
| delete PrefixOutput; // Free experiment |
| return NoFailure; |
| } |
| |
| class ReduceMiscompilingFunctions : public ListReducer<Function*> { |
| BugDriver &BD; |
| public: |
| ReduceMiscompilingFunctions(BugDriver &bd) : BD(bd) {} |
| |
| virtual TestResult doTest(std::vector<Function*> &Prefix, |
| std::vector<Function*> &Suffix) { |
| if (!Suffix.empty() && TestFuncs(Suffix, false)) |
| return KeepSuffix; |
| if (!Prefix.empty() && TestFuncs(Prefix, false)) |
| return KeepPrefix; |
| return NoFailure; |
| } |
| |
| bool TestFuncs(const std::vector<Function*> &Prefix, bool EmitBytecode); |
| }; |
| |
| bool ReduceMiscompilingFunctions::TestFuncs(const std::vector<Function*> &Funcs, |
| bool EmitBytecode) { |
| // Test to see if the function is misoptimized if we ONLY run it on the |
| // functions listed in Funcs. |
| if (!EmitBytecode) { |
| std::cout << "Checking to see if the program is misoptimized when these " |
| << "functions are run\nthrough the passes: "; |
| BD.PrintFunctionList(Funcs); |
| std::cout << "\n"; |
| } else { |
| std::cout <<"Outputting reduced bytecode files which expose the problem:\n"; |
| } |
| |
| // First step: clone the module for the two halves of the program we want. |
| Module *ToOptimize = CloneModule(BD.Program); |
| |
| // Second step: Make sure functions & globals are all external so that linkage |
| // between the two modules will work. |
| for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I) |
| I->setLinkage(GlobalValue::ExternalLinkage); |
| for (Module::giterator I = ToOptimize->gbegin(), E = ToOptimize->gend(); |
| I != E; ++I) |
| I->setLinkage(GlobalValue::ExternalLinkage); |
| |
| // Third step: make a clone of the externalized program for the non-optimized |
| // part. |
| Module *ToNotOptimize = CloneModule(ToOptimize); |
| |
| // Fourth step: Remove the test functions from the ToNotOptimize module, and |
| // all of the global variables. |
| for (unsigned i = 0, e = Funcs.size(); i != e; ++i) { |
| Function *TNOF = ToNotOptimize->getFunction(Funcs[i]->getName(), |
| Funcs[i]->getFunctionType()); |
| assert(TNOF && "Function doesn't exist in module!"); |
| DeleteFunctionBody(TNOF); // Function is now external in this module! |
| } |
| for (Module::giterator I = ToNotOptimize->gbegin(), E = ToNotOptimize->gend(); |
| I != E; ++I) |
| I->setInitializer(0); // Delete the initializer to make it external |
| |
| if (EmitBytecode) { |
| std::cout << " Non-optimized portion: "; |
| std::swap(BD.Program, ToNotOptimize); |
| BD.EmitProgressBytecode("tonotoptimize", true); |
| std::swap(BD.Program, ToNotOptimize); |
| } |
| |
| // Fifth step: Remove all functions from the ToOptimize module EXCEPT for the |
| // ones specified in Funcs. We know which ones these are because they are |
| // non-external in ToOptimize, but external in ToNotOptimize. |
| // |
| for (Module::iterator I = ToOptimize->begin(), E = ToOptimize->end();I!=E;++I) |
| if (!I->isExternal()) { |
| Function *TNOF = ToNotOptimize->getFunction(I->getName(), |
| I->getFunctionType()); |
| assert(TNOF && "Function doesn't exist in ToNotOptimize module??"); |
| if (!TNOF->isExternal()) |
| DeleteFunctionBody(I); |
| } |
| |
| if (EmitBytecode) { |
| std::cout << " Portion that is input to optimizer: "; |
| std::swap(BD.Program, ToOptimize); |
| BD.EmitProgressBytecode("tooptimize"); |
| std::swap(BD.Program, ToOptimize); |
| } |
| |
| // Sixth step: Run the optimization passes on ToOptimize, producing a |
| // transformed version of the functions being tested. |
| Module *OldProgram = BD.Program; |
| BD.Program = ToOptimize; |
| |
| if (!EmitBytecode) |
| std::cout << " Optimizing functions being tested: "; |
| std::string BytecodeResult; |
| if (BD.runPasses(BD.PassesToRun, BytecodeResult, false/*delete*/, |
| true/*quiet*/)) { |
| std::cerr << " Error running this sequence of passes" |
| << " on the input program!\n"; |
| BD.EmitProgressBytecode("pass-error", false); |
| exit(BD.debugCrash()); |
| } |
| |
| if (!EmitBytecode) |
| std::cout << "done.\n"; |
| |
| delete BD.Program; // Delete the old "ToOptimize" module |
| BD.Program = BD.ParseInputFile(BytecodeResult); |
| |
| if (EmitBytecode) { |
| std::cout << " 'tooptimize' after being optimized: "; |
| BD.EmitProgressBytecode("optimized", true); |
| } |
| |
| if (BD.Program == 0) { |
| std::cerr << BD.getToolName() << ": Error reading bytecode file '" |
| << BytecodeResult << "'!\n"; |
| exit(1); |
| } |
| removeFile(BytecodeResult); // No longer need the file on disk |
| |
| // Seventh step: Link the optimized part of the program back to the |
| // unoptimized part of the program. |
| // |
| if (LinkModules(BD.Program, ToNotOptimize, &BytecodeResult)) { |
| std::cerr << BD.getToolName() << ": Error linking modules together:" |
| << BytecodeResult << "\n"; |
| exit(1); |
| } |
| delete ToNotOptimize; // We are done with this module... |
| |
| if (EmitBytecode) { |
| std::cout << " Program as tested: "; |
| BD.EmitProgressBytecode("linked", true); |
| delete BD.Program; |
| BD.Program = OldProgram; |
| return false; // We don't need to actually execute the program here. |
| } |
| |
| std::cout << " Checking to see if the merged program executes correctly: "; |
| |
| // Eighth step: Execute the program. If it does not match the expected |
| // output, then 'Funcs' are being misoptimized! |
| bool Broken = BD.diffProgram(); |
| |
| delete BD.Program; // Delete the hacked up program |
| BD.Program = OldProgram; // Restore the original |
| |
| std::cout << (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 (!ReduceMiscompilingPasses(*this).reduceList(PassesToRun)) { |
| std::cerr << "*** Optimized program matches reference output! No problem " |
| << "detected...\nbugpoint can't help you with your problem!\n"; |
| return false; |
| } |
| |
| std::cout << "\n*** Found miscompiling pass" |
| << (PassesToRun.size() == 1 ? "" : "es") << ": " |
| << getPassesString(PassesToRun) << "\n"; |
| EmitProgressBytecode("passinput"); |
| |
| // 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; |
| for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I) |
| if (!I->isExternal()) |
| MiscompiledFunctions.push_back(I); |
| |
| // Do the reduction... |
| ReduceMiscompilingFunctions(*this).reduceList(MiscompiledFunctions); |
| |
| std::cout << "\n*** The following functions are being miscompiled: "; |
| PrintFunctionList(MiscompiledFunctions); |
| std::cout << "\n"; |
| |
| // Output a bunch of bytecode files for the user... |
| ReduceMiscompilingFunctions(*this).TestFuncs(MiscompiledFunctions, true); |
| |
| return false; |
| } |
| |
| } // End llvm namespace |