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llvm-mirror/tools/bugpoint/CodeGeneratorBug.cpp
Chris Lattner f856e42795 Minor cleanups, remove some old debug code 
llvm-svn: 12676
2004-04-05 21:37:55 +00:00

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//===- CodeGeneratorBug.cpp - Debug code generation bugs ------------------===//
//
// 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 code generation debugging support.
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "ListReducer.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalValue.h"
#include "llvm/iMemory.h"
#include "llvm/iTerminators.h"
#include "llvm/iOther.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Linker.h"
#include "Support/CommandLine.h"
#include "Support/Debug.h"
#include "Support/StringExtras.h"
#include "Support/FileUtilities.h"
using namespace llvm;
namespace llvm {
extern cl::list<std::string> InputArgv;
class ReduceMisCodegenFunctions : public ListReducer<Function*> {
BugDriver &BD;
public:
ReduceMisCodegenFunctions(BugDriver &bd) : BD(bd) {}
virtual TestResult doTest(std::vector<Function*> &Prefix,
std::vector<Function*> &Suffix) {
if (!Prefix.empty() && TestFuncs(Prefix))
return KeepPrefix;
if (!Suffix.empty() && TestFuncs(Suffix))
return KeepSuffix;
return NoFailure;
}
bool TestFuncs(const std::vector<Function*> &CodegenTest,
bool KeepFiles = false);
};
}
bool ReduceMisCodegenFunctions::TestFuncs(const std::vector<Function*> &Funcs,
bool KeepFiles) {
std::cout << "Testing functions: ";
PrintFunctionList(Funcs);
std::cout << "\t";
// Clone the module for the two halves of the program we want.
Module *SafeModule = CloneModule(BD.getProgram());
// The JIT must extract the 'main' function.
std::vector<Function*> RealFuncs(Funcs);
if (BD.isExecutingJIT()) {
if (Function *F = BD.Program->getMainFunction())
RealFuncs.push_back(F);
}
Module *TestModule = SplitFunctionsOutOfModule(SafeModule, RealFuncs);
// This is only applicable if we are debugging the JIT:
// Find all external functions in the Safe modules that are actually used
// (called or taken address of), and make them call the JIT wrapper instead
if (BD.isExecutingJIT()) {
// Must delete `main' from Safe module if it has it
Function *safeMain = SafeModule->getNamedFunction("main");
assert(safeMain && "`main' function not found in safe module!");
DeleteFunctionBody(safeMain);
// Add an external function "getPointerToNamedFunction" that JIT provides
// Prototype: void *getPointerToNamedFunction(const char* Name)
std::vector<const Type*> Params;
Params.push_back(PointerType::get(Type::SByteTy)); // std::string&
FunctionType *resolverTy = FunctionType::get(PointerType::get(Type::VoidTy),
Params, false /* isVarArg */);
Function *resolverFunc = new Function(resolverTy,
GlobalValue::ExternalLinkage,
"getPointerToNamedFunction",
SafeModule);
// Use the function we just added to get addresses of functions we need
// Iterate over the global declarations in the Safe module
for (Module::iterator F=SafeModule->begin(),E=SafeModule->end(); F!=E; ++F){
if (F->isExternal() && !F->use_empty() && &*F != resolverFunc &&
F->getIntrinsicID() == 0 /* ignore intrinsics */ &&
// Don't forward functions which are external in the test module too.
!TestModule->getNamedFunction(F->getName())->isExternal()) {
// If it has a non-zero use list,
// 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", SafeModule);
// 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
// sbyte* so it matches the signature of the resolver function.
std::vector<Constant*> GEPargs(2, Constant::getNullValue(Type::IntTy));
// 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
// GetElementPtr *funcName, ulong 0, ulong 0
Value *GEP =
ConstantExpr::getGetElementPtr(ConstantPointerRef::get(funcName),
GEPargs);
std::vector<Value*> ResolverArgs;
ResolverArgs.push_back(GEP);
// 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(*SafeModule) || verifyModule(*TestModule)) {
std::cerr << "Bugpoint has a bug, an corrupted a module!!\n";
abort();
}
// Remove all functions from the Test 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 = TestModule->begin(), E = TestModule->end();I!=E;++I)
if (!I->isExternal()) {
Function *TNOF = SafeModule->getFunction(I->getName(),
I->getFunctionType());
assert(TNOF && "Function doesn't exist in ToNotOptimize module??");
if (!TNOF->isExternal())
DeleteFunctionBody(I);
}
// Clean up the modules, removing extra cruft that we don't need anymore...
TestModule = BD.performFinalCleanups(TestModule);
std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc");
if (BD.writeProgramToFile(TestModuleBC, TestModule)) {
std::cerr << "Error writing bytecode to `" << TestModuleBC << "'\nExiting.";
exit(1);
}
delete TestModule;
// Make the shared library
std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc");
if (BD.writeProgramToFile(SafeModuleBC, SafeModule)) {
std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
exit(1);
}
std::string SharedObject = BD.compileSharedObject(SafeModuleBC);
delete SafeModule;
// 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";
if (KeepFiles) {
std::cout << "You can reproduce the problem with the command line: \n";
if (BD.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";
} else {
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);
DEBUG(std::cerr << "Disambiguating globals (external-only)\n");
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
I->setName(Mang.getValueName(I));
DEBUG(std::cerr << "Disambiguating functions (external-only)\n");
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;
}
// 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*> MisCodegenFunctions;
for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
if (!I->isExternal())
MisCodegenFunctions.push_back(I);
// If we are executing the JIT, we *must* keep the function `main' in the
// module that is passed in, and not the shared library. However, we still
// want to be able to debug the `main' function alone. Thus, we create a new
// function `main' which just calls the old one.
if (isExecutingJIT()) {
// Get the `main' function
Function *oldMain = Program->getNamedFunction("main");
assert(oldMain && "`main' function not found in program!");
// Rename it
oldMain->setName("llvm_old_main");
// Create a NEW `main' function with same type
Function *newMain = new Function(oldMain->getFunctionType(),
GlobalValue::ExternalLinkage,
"main", Program);
// Call the old main function and return its result
BasicBlock *BB = new BasicBlock("entry", newMain);
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);
}
CallInst *call = new CallInst(oldMain, args);
BB->getInstList().push_back(call);
// if the type of old function wasn't void, return value of call
if (oldMain->getReturnType() != Type::VoidTy) {
new ReturnInst(call, BB);
} else {
new ReturnInst(0, BB);
}
}
DisambiguateGlobalSymbols(Program);
// Do the reduction...
if (!ReduceMisCodegenFunctions(*this).reduceList(MisCodegenFunctions)) {
std::cerr << "*** Execution matches reference output! "
<< "bugpoint can't help you with your problem!\n";
return false;
}
std::cout << "\n*** The following functions are being miscompiled: ";
PrintFunctionList(MisCodegenFunctions);
std::cout << "\n";
// Output a bunch of bytecode files for the user...
ReduceMisCodegenFunctions(*this).TestFuncs(MisCodegenFunctions, true);
return false;
}
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