llvm-6502/tools/bugpoint/CrashDebugger.cpp
2005-03-15 15:48:06 +00:00

448 lines
16 KiB
C++

//===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
//
// 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 defines the bugpoint internals that narrow down compilation crashes
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "ListReducer.h"
#include "llvm/Constant.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/SymbolTable.h"
#include "llvm/Type.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Bytecode/Writer.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/ToolRunner.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Support/FileUtilities.h"
#include <fstream>
#include <set>
using namespace llvm;
namespace llvm {
class ReducePassList : public ListReducer<const PassInfo*> {
BugDriver &BD;
public:
ReducePassList(BugDriver &bd) : BD(bd) {}
// doTest - Return true iff running the "removed" passes succeeds, and
// running the "Kept" passes fail when run on the output of the "removed"
// passes. If we return true, we update the current module of bugpoint.
//
virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
std::vector<const PassInfo*> &Kept);
};
}
ReducePassList::TestResult
ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
std::vector<const PassInfo*> &Suffix) {
sys::Path PrefixOutput;
Module *OrigProgram = 0;
if (!Prefix.empty()) {
std::cout << "Checking to see if these passes crash: "
<< getPassesString(Prefix) << ": ";
std::string PfxOutput;
if (BD.runPasses(Prefix, PfxOutput))
return KeepPrefix;
PrefixOutput.setFile(PfxOutput);
OrigProgram = BD.Program;
BD.Program = ParseInputFile(PrefixOutput.toString());
if (BD.Program == 0) {
std::cerr << BD.getToolName() << ": Error reading bytecode file '"
<< PrefixOutput << "'!\n";
exit(1);
}
PrefixOutput.destroyFile();
}
std::cout << "Checking to see if these passes crash: "
<< getPassesString(Suffix) << ": ";
if (BD.runPasses(Suffix)) {
delete OrigProgram; // The suffix crashes alone...
return KeepSuffix;
}
// Nothing failed, restore state...
if (OrigProgram) {
delete BD.Program;
BD.Program = OrigProgram;
}
return NoFailure;
}
namespace llvm {
class ReduceCrashingFunctions : public ListReducer<Function*> {
BugDriver &BD;
bool (*TestFn)(BugDriver &, Module *);
public:
ReduceCrashingFunctions(BugDriver &bd,
bool (*testFn)(BugDriver &, Module *))
: BD(bd), TestFn(testFn) {}
virtual TestResult doTest(std::vector<Function*> &Prefix,
std::vector<Function*> &Kept) {
if (!Kept.empty() && TestFuncs(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestFuncs(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestFuncs(std::vector<Function*> &Prefix);
};
}
bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
// Clone the program to try hacking it apart...
Module *M = CloneModule(BD.getProgram());
// Convert list to set for fast lookup...
std::set<Function*> Functions;
for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
Function *CMF = M->getFunction(Funcs[i]->getName(),
Funcs[i]->getFunctionType());
assert(CMF && "Function not in module?!");
Functions.insert(CMF);
}
std::cout << "Checking for crash with only these functions: ";
PrintFunctionList(Funcs);
std::cout << ": ";
// Loop over and delete any functions which we aren't supposed to be playing
// with...
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
if (!I->isExternal() && !Functions.count(I))
DeleteFunctionBody(I);
// Try running the hacked up program...
if (TestFn(BD, M)) {
BD.setNewProgram(M); // It crashed, keep the trimmed version...
// Make sure to use function pointers that point into the now-current
// module.
Funcs.assign(Functions.begin(), Functions.end());
return true;
}
delete M;
return false;
}
namespace {
/// ReduceCrashingBlocks reducer - This works by setting the terminators of
/// all terminators except the specified basic blocks to a 'ret' instruction,
/// then running the simplify-cfg pass. This has the effect of chopping up
/// the CFG really fast which can reduce large functions quickly.
///
class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
BugDriver &BD;
bool (*TestFn)(BugDriver &, Module *);
public:
ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
: BD(bd), TestFn(testFn) {}
virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
std::vector<const BasicBlock*> &Kept) {
if (!Kept.empty() && TestBlocks(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestBlocks(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
};
}
bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
// Clone the program to try hacking it apart...
Module *M = CloneModule(BD.getProgram());
// Convert list to set for fast lookup...
std::set<BasicBlock*> Blocks;
for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
// Convert the basic block from the original module to the new module...
const Function *F = BBs[i]->getParent();
Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
assert(CMF && "Function not in module?!");
// Get the mapped basic block...
Function::iterator CBI = CMF->begin();
std::advance(CBI, std::distance(F->begin(),
Function::const_iterator(BBs[i])));
Blocks.insert(CBI);
}
std::cout << "Checking for crash with only these blocks:";
unsigned NumPrint = Blocks.size();
if (NumPrint > 10) NumPrint = 10;
for (unsigned i = 0, e = NumPrint; i != e; ++i)
std::cout << " " << BBs[i]->getName();
if (NumPrint < Blocks.size())
std::cout << "... <" << Blocks.size() << " total>";
std::cout << ": ";
// Loop over and delete any hack up any blocks that are not listed...
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
// Loop over all of the successors of this block, deleting any PHI nodes
// that might include it.
for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
(*SI)->removePredecessor(BB);
if (BB->getTerminator()->getType() != Type::VoidTy)
BB->getTerminator()->replaceAllUsesWith(
Constant::getNullValue(BB->getTerminator()->getType()));
// Delete the old terminator instruction...
BB->getInstList().pop_back();
// Add a new return instruction of the appropriate type...
const Type *RetTy = BB->getParent()->getReturnType();
new ReturnInst(RetTy == Type::VoidTy ? 0 :
Constant::getNullValue(RetTy), BB);
}
// The CFG Simplifier pass may delete one of the basic blocks we are
// interested in. If it does we need to take the block out of the list. Make
// a "persistent mapping" by turning basic blocks into <function, name> pairs.
// This won't work well if blocks are unnamed, but that is just the risk we
// have to take.
std::vector<std::pair<Function*, std::string> > BlockInfo;
for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
I != E; ++I)
BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));
// Now run the CFG simplify pass on the function...
PassManager Passes;
Passes.add(createCFGSimplificationPass());
Passes.add(createVerifierPass());
Passes.run(*M);
// Try running on the hacked up program...
if (TestFn(BD, M)) {
BD.setNewProgram(M); // It crashed, keep the trimmed version...
// Make sure to use basic block pointers that point into the now-current
// module, and that they don't include any deleted blocks.
BBs.clear();
for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
SymbolTable &ST = BlockInfo[i].first->getSymbolTable();
SymbolTable::plane_iterator PI = ST.find(Type::LabelTy);
if (PI != ST.plane_end() && PI->second.count(BlockInfo[i].second))
BBs.push_back(cast<BasicBlock>(PI->second[BlockInfo[i].second]));
}
return true;
}
delete M; // It didn't crash, try something else.
return false;
}
/// DebugACrash - Given a predicate that determines whether a component crashes
/// on a program, try to destructively reduce the program while still keeping
/// the predicate true.
static bool DebugACrash(BugDriver &BD, bool (*TestFn)(BugDriver &, Module *)) {
bool AnyReduction = false;
// See if we can get away with nuking all of the global variable initializers
// in the program...
if (BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
Module *M = CloneModule(BD.getProgram());
bool DeletedInit = false;
for (Module::global_iterator I = M->global_begin(), E = M->global_end(); I != E; ++I)
if (I->hasInitializer()) {
I->setInitializer(0);
I->setLinkage(GlobalValue::ExternalLinkage);
DeletedInit = true;
}
if (!DeletedInit) {
delete M; // No change made...
} else {
// See if the program still causes a crash...
std::cout << "\nChecking to see if we can delete global inits: ";
if (TestFn(BD, M)) { // Still crashes?
BD.setNewProgram(M);
AnyReduction = true;
std::cout << "\n*** Able to remove all global initializers!\n";
} else { // No longer crashes?
std::cout << " - Removing all global inits hides problem!\n";
delete M;
}
}
}
// Now try to reduce the number of functions in the module to something small.
std::vector<Function*> Functions;
for (Module::iterator I = BD.getProgram()->begin(),
E = BD.getProgram()->end(); I != E; ++I)
if (!I->isExternal())
Functions.push_back(I);
if (Functions.size() > 1) {
std::cout << "\n*** Attempting to reduce the number of functions "
"in the testcase\n";
unsigned OldSize = Functions.size();
ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
if (Functions.size() < OldSize) {
BD.EmitProgressBytecode("reduced-function");
AnyReduction = true;
}
}
// Attempt to delete entire basic blocks at a time to speed up
// convergence... this actually works by setting the terminator of the blocks
// to a return instruction then running simplifycfg, which can potentially
// shrinks the code dramatically quickly
//
if (!DisableSimplifyCFG) {
std::vector<const BasicBlock*> Blocks;
for (Module::const_iterator I = BD.getProgram()->begin(),
E = BD.getProgram()->end(); I != E; ++I)
for (Function::const_iterator FI = I->begin(), E = I->end(); FI !=E; ++FI)
Blocks.push_back(FI);
ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
}
// FIXME: This should use the list reducer to converge faster by deleting
// larger chunks of instructions at a time!
unsigned Simplification = 2;
do {
--Simplification;
std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
<< "tions: Simplification Level #" << Simplification << '\n';
// Now that we have deleted the functions that are unnecessary for the
// program, try to remove instructions that are not necessary to cause the
// crash. To do this, we loop through all of the instructions in the
// remaining functions, deleting them (replacing any values produced with
// nulls), and then running ADCE and SimplifyCFG. If the transformed input
// still triggers failure, keep deleting until we cannot trigger failure
// anymore.
//
unsigned InstructionsToSkipBeforeDeleting = 0;
TryAgain:
// Loop over all of the (non-terminator) instructions remaining in the
// function, attempting to delete them.
unsigned CurInstructionNum = 0;
for (Module::const_iterator FI = BD.getProgram()->begin(),
E = BD.getProgram()->end(); FI != E; ++FI)
if (!FI->isExternal())
for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
++BI)
for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
I != E; ++I, ++CurInstructionNum)
if (InstructionsToSkipBeforeDeleting) {
--InstructionsToSkipBeforeDeleting;
} else {
std::cout << "Checking instruction '" << I->getName() << "': ";
Module *M = BD.deleteInstructionFromProgram(I, Simplification);
// Find out if the pass still crashes on this pass...
if (TestFn(BD, M)) {
// Yup, it does, we delete the old module, and continue trying
// to reduce the testcase...
BD.setNewProgram(M);
AnyReduction = true;
InstructionsToSkipBeforeDeleting = CurInstructionNum;
goto TryAgain; // I wish I had a multi-level break here!
}
// This pass didn't crash without this instruction, try the next
// one.
delete M;
}
if (InstructionsToSkipBeforeDeleting) {
InstructionsToSkipBeforeDeleting = 0;
goto TryAgain;
}
} while (Simplification);
// Try to clean up the testcase by running funcresolve and globaldce...
std::cout << "\n*** Attempting to perform final cleanups: ";
Module *M = CloneModule(BD.getProgram());
M = BD.performFinalCleanups(M, true);
// Find out if the pass still crashes on the cleaned up program...
if (TestFn(BD, M)) {
BD.setNewProgram(M); // Yup, it does, keep the reduced version...
AnyReduction = true;
} else {
delete M;
}
if (AnyReduction)
BD.EmitProgressBytecode("reduced-simplified");
return false;
}
static bool TestForOptimizerCrash(BugDriver &BD, Module *M) {
return BD.runPasses(M);
}
/// debugOptimizerCrash - This method is called when some pass crashes on input.
/// It attempts to prune down the testcase to something reasonable, and figure
/// out exactly which pass is crashing.
///
bool BugDriver::debugOptimizerCrash() {
std::cout << "\n*** Debugging optimizer crash!\n";
// Reduce the list of passes which causes the optimizer to crash...
unsigned OldSize = PassesToRun.size();
ReducePassList(*this).reduceList(PassesToRun);
std::cout << "\n*** Found crashing pass"
<< (PassesToRun.size() == 1 ? ": " : "es: ")
<< getPassesString(PassesToRun) << '\n';
EmitProgressBytecode("passinput");
return DebugACrash(*this, TestForOptimizerCrash);
}
static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
try {
std::cerr << '\n';
BD.compileProgram(M);
std::cerr << '\n';
return false;
} catch (ToolExecutionError &) {
std::cerr << "<crash>\n";
return true; // Tool is still crashing.
}
}
/// debugCodeGeneratorCrash - This method is called when the code generator
/// crashes on an input. It attempts to reduce the input as much as possible
/// while still causing the code generator to crash.
bool BugDriver::debugCodeGeneratorCrash() {
std::cerr << "*** Debugging code generator crash!\n";
return DebugACrash(*this, TestForCodeGenCrash);
}