[llvm-commits] CVS: llvm/tools/bugpoint/BugDriver.h Miscompilation.cpp CodeGeneratorBug.cpp
Chris Lattner
lattner at cs.uiuc.edu
Mon Apr 5 17:59:02 PDT 2004
Changes in directory llvm/tools/bugpoint:
BugDriver.h updated: 1.36 -> 1.37
Miscompilation.cpp updated: 1.36 -> 1.37
CodeGeneratorBug.cpp (r1.43) removed
---
Log message:
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. :)
---
Diffs of the changes: (+265 -1)
Index: llvm/tools/bugpoint/BugDriver.h
diff -u llvm/tools/bugpoint/BugDriver.h:1.36 llvm/tools/bugpoint/BugDriver.h:1.37
--- llvm/tools/bugpoint/BugDriver.h:1.36 Mon Apr 5 17:01:48 2004
+++ llvm/tools/bugpoint/BugDriver.h Mon Apr 5 17:58:16 2004
@@ -129,6 +129,16 @@
return OldProgram;
}
+ AbstractInterpreter *switchToCBE() {
+ AbstractInterpreter *Old = Interpreter;
+ Interpreter = (AbstractInterpreter*)cbe;
+ return Old;
+ }
+
+ void switchToInterpreter(AbstractInterpreter *AI) {
+ Interpreter = AI;
+ }
+
/// setNewProgram - If we reduce or update the program somehow, call this
/// method to update bugdriver with it. This deletes the old module and sets
/// the specified one as the current program.
Index: llvm/tools/bugpoint/Miscompilation.cpp
diff -u llvm/tools/bugpoint/Miscompilation.cpp:1.36 llvm/tools/bugpoint/Miscompilation.cpp:1.37
--- llvm/tools/bugpoint/Miscompilation.cpp:1.36 Mon Apr 5 16:37:38 2004
+++ llvm/tools/bugpoint/Miscompilation.cpp Mon Apr 5 17:58:16 2004
@@ -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 @@
// 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 @@
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 @@
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 @@
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;
+}
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