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a1a7148c4de22a2cedc76b97ef80569b36698342
llvm-6502/tools/bugpoint/CodeGeneratorBug.cpp
Chris Lattner be21ca54e0 Refactor all of the "splitting a module into two pieces" code to avoid 
code duplication.  Also, don't use ReduceMiscompilingFunctions::TestFuncs
to print out the final message.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12387 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-14 19:27:19 +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"
#include <algorithm>
#include <set>
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: ";
BD.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
// The correct type is `const [ NUM x sbyte ]' where NUM is length of
// function name + 1
const std::string &Name = F->getName();
GlobalVariable *funcName =
new GlobalVariable(ArrayType::get(Type::SByteTy, Name.length()+1),
true /* isConstant */,
GlobalValue::InternalLinkage,
ConstantArray::get(Name),
Name + "_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::LongTy));
// 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();
}
DEBUG(std::cerr << "Safe module:\n";
typedef Module::iterator MI;
typedef Module::giterator MGI;
for (MI I = SafeModule->begin(), E = SafeModule->end(); I != E; ++I)
if (!I->isExternal()) std::cerr << "\t" << I->getName() << "\n";
for (MGI I = SafeModule->gbegin(), E = SafeModule->gend(); I!=E; ++I)
if (!I->isExternal()) std::cerr << "\t" << I->getName() << "\n";
std::cerr << "Test module:\n";
for (MI I = TestModule->begin(), E = TestModule->end(); I != E; ++I)
if (!I->isExternal()) std::cerr << "\t" << I->getName() << "\n";
for (MGI I=TestModule->gbegin(),E = TestModule->gend(); I!= E; ++I)
if (!I->isExternal()) std::cerr << "\t" << I->getName() << "\n";
);
// Write out the bytecode to be sent to CBE
std::string SafeModuleBC = getUniqueFilename("bugpoint.safe.bc");
if (BD.writeProgramToFile(SafeModuleBC, SafeModule)) {
std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
exit(1);
}
// 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);
}
std::string TestModuleBC = getUniqueFilename("bugpoint.test.bc");
if (verifyModule(*TestModule)) {
std::cerr << "Bytecode file corrupted!\n";
exit(1);
}
// Clean up the modules, removing extra cruft that we don't need anymore...
SafeModule = BD.performFinalCleanups(SafeModule);
TestModule = BD.performFinalCleanups(TestModule);
if (BD.writeProgramToFile(TestModuleBC, TestModule)) {
std::cerr << "Error writing bytecode to `" << SafeModuleBC << "'\nExiting.";
exit(1);
}
// Make a shared library
std::string SharedObject = BD.compileSharedObject(SafeModuleBC);
delete SafeModule;
delete TestModule;
// 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;
}
namespace {
struct Disambiguator {
std::set<std::string> SymbolNames;
std::set<GlobalValue*> Symbols;
uint64_t uniqueCounter;
bool externalOnly;
public:
Disambiguator() : uniqueCounter(0), externalOnly(true) {}
void setExternalOnly(bool value) { externalOnly = value; }
void add(GlobalValue &V) {
// If we're only processing externals and this isn't external, bail
if (externalOnly && !V.isExternal()) return;
// If we're already processed this symbol, don't add it again
if (Symbols.count(&V) != 0) return;
// Ignore intrinsic functions
if (Function *F = dyn_cast<Function>(&V))
if (F->getIntrinsicID() != 0)
return;
std::string SymName = V.getName();
// Use the Mangler facility to make symbol names that will be valid in
// shared objects.
SymName = Mangler::makeNameProper(SymName);
V.setName(SymName);
if (SymbolNames.count(SymName) == 0) {
DEBUG(std::cerr << "Disambiguator: adding " << SymName
<< ", no conflicts.\n");
SymbolNames.insert(SymName);
} else {
// Mangle name before adding
std::string newName;
do {
newName = SymName + "_" + utostr(uniqueCounter);
if (SymbolNames.count(newName) == 0) break;
else ++uniqueCounter;
} while (1);
//while (SymbolNames.count(V->getName()+utostr(uniqueCounter++))==0);
DEBUG(std::cerr << "Disambiguator: conflict: " << SymName
<< ", adding: " << newName << "\n");
V.setName(newName);
SymbolNames.insert(newName);
}
Symbols.insert(&V);
}
};
}
static void DisambiguateGlobalSymbols(Module *M) {
// First, try not to cause collisions by minimizing chances of renaming an
// already-external symbol, so take in external globals and functions as-is.
Disambiguator D;
DEBUG(std::cerr << "Disambiguating globals (external-only)\n");
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I) D.add(*I);
DEBUG(std::cerr << "Disambiguating functions (external-only)\n");
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) D.add(*I);
// Now just rename functions and globals as necessary, keeping what's already
// in the set unique.
D.setExternalOnly(false);
DEBUG(std::cerr << "Disambiguating globals\n");
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I) D.add(*I);
DEBUG(std::cerr << "Disambiguating globals\n");
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) D.add(*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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