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author | Chris Lattner <sabre@nondot.org> | 2004-04-05 22:58:16 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2004-04-05 22:58:16 +0000 |
commit | a57d86b436549503a7f96c5266444e022bdbaf55 (patch) | |
tree | 3c12d8f5aae9aa197c07c1ebf3c12b7c5e6843e8 /tools/bugpoint/Miscompilation.cpp | |
parent | 11b8cd197a740bc9af2f27cb88d535c4be2cdd0e (diff) | |
download | llvm-a57d86b436549503a7f96c5266444e022bdbaf55.tar.gz llvm-a57d86b436549503a7f96c5266444e022bdbaf55.tar.bz2 llvm-a57d86b436549503a7f96c5266444e022bdbaf55.tar.xz |
Merge the code generator miscompilation code into the optimizer miscompilation
code. This "instantly" gives us loop-extractor power to assist with the
debugment of our nasty codegen issues. :)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12678 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'tools/bugpoint/Miscompilation.cpp')
-rw-r--r-- | tools/bugpoint/Miscompilation.cpp | 256 |
1 files changed, 255 insertions, 1 deletions
diff --git a/tools/bugpoint/Miscompilation.cpp b/tools/bugpoint/Miscompilation.cpp index 9b9a020c3f..32dea94d8a 100644 --- a/tools/bugpoint/Miscompilation.cpp +++ b/tools/bugpoint/Miscompilation.cpp @@ -7,19 +7,30 @@ // //===----------------------------------------------------------------------===// // -// This file implements program miscompilation debugging support. +// This file implements optimizer and code generation miscompilation debugging +// support. // //===----------------------------------------------------------------------===// #include "BugDriver.h" #include "ListReducer.h" +#include "llvm/Constants.h" +#include "llvm/DerivedTypes.h" +#include "llvm/Instructions.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/Transforms/Utils/Linker.h" +#include "Support/CommandLine.h" #include "Support/FileUtilities.h" using namespace llvm; +namespace llvm { + extern cl::list<std::string> InputArgv; +} + namespace { class ReduceMiscompilingPasses : public ListReducer<const PassInfo*> { BugDriver &BD; @@ -218,7 +229,10 @@ static bool ExtractLoops(BugDriver &BD, // 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.switchToCBE(); if (TestMergedProgram(BD, ToOptimizeLoopExtracted, ToNotOptimize, false)) { + BD.switchToInterpreter(AI); + // Merged program doesn't work anymore! std::cerr << " *** ERROR: Loop extraction broke the program. :(" << " Please report a bug!\n"; @@ -227,6 +241,7 @@ static bool ExtractLoops(BugDriver &BD, delete ToOptimizeLoopExtracted; return MadeChange; } + BD.switchToInterpreter(AI); std::cout << " Testing after loop extraction:\n"; // Clone modules, the tester function will free them. @@ -319,6 +334,9 @@ DebugAMiscompilation(BugDriver &BD, 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. @@ -374,3 +392,239 @@ bool BugDriver::debugMiscompilation() { 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->getNamedFunction("main")) + if (!oldMain->isExternal()) { + // Rename it + oldMain->setName("llvm_bugpoint_old_main"); + // Create a NEW `main' function with same type in the test module. + Function *newMain = new Function(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 = new Function(oldMain->getFunctionType(), + GlobalValue::ExternalLinkage, + oldMain->getName(), Test); + // Set up and remember the argument list for the main function. + std::vector<Value*> args; + for (Function::aiterator I = newMain->abegin(), E = newMain->aend(), + OI = oldMain->abegin(); 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 = new BasicBlock("entry", newMain); + CallInst *call = new CallInst(oldMainProto, args); + BB->getInstList().push_back(call); + + // If the type of old function wasn't void, return value of call + new ReturnInst(oldMain->getReturnType() != Type::VoidTy ? call : 0, 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) + Function *resolverFunc = + Safe->getOrInsertFunction("getPointerToNamedFunction", + PointerType::get(Type::SByteTy), + PointerType::get(Type::SByteTy), 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->isExternal() && !F->use_empty() && &*F != resolverFunc && + F->getIntrinsicID() == 0 /* ignore intrinsics */) { + Function *TestFn =Test->getFunction(F->getName(), F->getFunctionType()); + + // Don't forward functions which are external in the test module too. + if (TestFn && !TestFn->isExternal()) { + // 1. Add a string constant with its name to the global file + Constant *InitArray = ConstantArray::get(F->getName()); + GlobalVariable *funcName = + new GlobalVariable(InitArray->getType(), true /*isConstant*/, + GlobalValue::InternalLinkage, InitArray, + F->getName() + "_name", Safe); + + // 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::IntTy)); + Value *GEP = + ConstantExpr::getGetElementPtr(ConstantPointerRef::get(funcName), + GEPargs); + std::vector<Value*> ResolverArgs; + ResolverArgs.push_back(GEP); + + // 3. Replace all uses of `func' with calls to resolver by: + // (a) Iterating through the list of uses of this function + // (b) Insert a cast instruction in front of each use + // (c) Replace use of old call with new call + + // Insert code at the beginning of the function + while (!F->use_empty()) + if (Instruction *Inst = dyn_cast<Instruction>(F->use_back())) { + // call resolver(GetElementPtr...) + CallInst *resolve = new CallInst(resolverFunc, ResolverArgs, + "resolver", Inst); + // cast the result from the resolver to correctly-typed function + CastInst *castResolver = + new CastInst(resolve, PointerType::get(F->getFunctionType()), + "resolverCast", Inst); + // actually use the resolved function + Inst->replaceUsesOfWith(F, castResolver); + } else { + // FIXME: need to take care of cases where a function is used by + // something other than an instruction; e.g., global variable + // initializers and constant expressions. + std::cerr << "UNSUPPORTED: Non-instruction is using an external " + << "function, " << F->getName() << "().\n"; + abort(); + } + } + } + } + + if (verifyModule(*Test) || verifyModule(*Safe)) { + std::cerr << "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); + + std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc"); + if (BD.writeProgramToFile(TestModuleBC, Test)) { + std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting."; + exit(1); + } + delete Test; + + // Make the shared library + std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc"); + + if (BD.writeProgramToFile(SafeModuleBC, Safe)) { + std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting."; + exit(1); + } + std::string SharedObject = BD.compileSharedObject(SafeModuleBC); + 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, SharedObject, false); + + if (Result) + std::cerr << ": still failing!\n"; + else + std::cerr << ": didn't fail.\n"; + removeFile(TestModuleBC); + removeFile(SafeModuleBC); + removeFile(SharedObject); + + return Result; +} + + + +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); + for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I) + I->setName(Mang.getValueName(I)); + for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) + I->setName(Mang.getValueName(I)); +} + + + +bool BugDriver::debugCodeGenerator() { + if ((void*)cbe == (void*)Interpreter) { + std::string Result = executeProgramWithCBE("bugpoint.cbe.out"); + std::cout << "\n*** The C backend cannot match the reference diff, but it " + << "is used as the 'known good'\n code generator, so I can't" + << " debug it. Perhaps you have a front-end problem?\n As a" + << " sanity check, I left the result of executing the program " + << "with the C backend\n 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. + Module *ToNotCodeGen = CloneModule(getProgram()); + Module *ToCodeGen = SplitFunctionsOutOfModule(ToNotCodeGen, Funcs); + + // Condition the modules + CleanupAndPrepareModules(*this, ToCodeGen, ToNotCodeGen); + + std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc"); + if (writeProgramToFile(TestModuleBC, ToCodeGen)) { + std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting."; + exit(1); + } + delete ToCodeGen; + + // Make the shared library + std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc"); + if (writeProgramToFile(SafeModuleBC, ToNotCodeGen)) { + std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting."; + exit(1); + } + std::string SharedObject = compileSharedObject(SafeModuleBC); + delete ToNotCodeGen; + + std::cout << "You can reproduce the problem with the command line: \n"; + if (isExecutingJIT()) { + std::cout << " lli -load " << SharedObject << " " << TestModuleBC; + } else { + std::cout << " llc " << TestModuleBC << " -o " << TestModuleBC << ".s\n"; + std::cout << " gcc " << SharedObject << " " << TestModuleBC + << ".s -o " << TestModuleBC << ".exe -Wl,-R.\n"; + std::cout << " " << TestModuleBC << ".exe"; + } + for (unsigned i=0, e = InputArgv.size(); i != e; ++i) + std::cout << " " << InputArgv[i]; + std::cout << "\n"; + std::cout << "The shared object was created with:\n llc -march=c " + << SafeModuleBC << " -o temporary.c\n" + << " gcc -xc temporary.c -O2 -o " << SharedObject +#if defined(sparc) || defined(__sparc__) || defined(__sparcv9) + << " -G" // Compile a shared library, `-G' for Sparc +#else + << " -shared" // `-shared' for Linux/X86, maybe others +#endif + << " -fno-strict-aliasing\n"; + + return false; +} |