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llvm-mirror/tools/bugpoint/CrashDebugger.cpp
Reid Spencer 4bafa71dc1 For PR786:
Turn on -Wunused and -Wno-unused-parameter. Clean up most of the resulting
fall out by removing unused variables. Remaining warnings have to do with
unused functions (I didn't want to delete code without review) and unused
variables in generated code. Maintainers should clean up the remaining
issues when they see them. All changes pass DejaGnu tests and Olden.

llvm-svn: 31380
2006-11-02 20:25:50 +00:00

560 lines
20 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 "ToolRunner.h"
#include "ListReducer.h"
#include "llvm/Constant.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/SymbolTable.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Bytecode/Writer.h"
#include "llvm/Support/CFG.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/CommandLine.h"
#include <fstream>
#include <set>
using namespace llvm;
namespace {
cl::opt<bool>
KeepMain("keep-main",
cl::desc("Force function reduction to keep main"),
cl::init(false));
}
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.set(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.eraseFromDisk();
}
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 {
/// ReduceCrashingGlobalVariables - This works by removing the global
/// variable's initializer and seeing if the program still crashes. If it
/// does, then we keep that program and try again.
///
class ReduceCrashingGlobalVariables : public ListReducer<GlobalVariable*> {
BugDriver &BD;
bool (*TestFn)(BugDriver &, Module *);
public:
ReduceCrashingGlobalVariables(BugDriver &bd,
bool (*testFn)(BugDriver&, Module*))
: BD(bd), TestFn(testFn) {}
virtual TestResult doTest(std::vector<GlobalVariable*>& Prefix,
std::vector<GlobalVariable*>& Kept) {
if (!Kept.empty() && TestGlobalVariables(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestGlobalVariables(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestGlobalVariables(std::vector<GlobalVariable*>& GVs);
};
}
bool
ReduceCrashingGlobalVariables::TestGlobalVariables(
std::vector<GlobalVariable*>& GVs) {
// Clone the program to try hacking it apart...
Module *M = CloneModule(BD.getProgram());
// Convert list to set for fast lookup...
std::set<GlobalVariable*> GVSet;
for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
GlobalVariable* CMGV = M->getNamedGlobal(GVs[i]->getName());
assert(CMGV && "Global Variable not in module?!");
GVSet.insert(CMGV);
}
std::cout << "Checking for crash with only these global variables: ";
PrintGlobalVariableList(GVs);
std::cout << ": ";
// Loop over and delete any global variables which we aren't supposed to be
// playing with...
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);
}
// Try running the hacked up program...
if (TestFn(BD, M)) {
BD.setNewProgram(M); // It crashed, keep the trimmed version...
// Make sure to use global variable pointers that point into the now-current
// module.
GVs.assign(GVSet.begin(), GVSet.end());
return true;
}
delete M;
return false;
}
namespace llvm {
/// ReduceCrashingFunctions reducer - This works by removing functions and
/// seeing if the program still crashes. If it does, then keep the newer,
/// smaller program.
///
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) {
//if main isn't present, claim there is no problem
if (KeepMain && find(Funcs.begin(), Funcs.end(),
BD.getProgram()->getMainFunction()) == Funcs.end())
return false;
// 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) {
// FIXME: bugpoint should add names to all stripped symbols.
assert(!Funcs[i]->getName().empty() &&
"Bugpoint doesn't work on stripped modules yet PR718!");
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 *)) {
// See if we can get away with nuking some of the global variable initializers
// in the program...
if (BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
// Now try to reduce the number of global variable initializers in the
// module to something small.
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);
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;
std::vector<GlobalVariable*> GVs;
for (Module::global_iterator I = BD.getProgram()->global_begin(),
E = BD.getProgram()->global_end(); I != E; ++I)
if (I->hasInitializer())
GVs.push_back(I);
if (GVs.size() > 1 && !BugpointIsInterrupted) {
std::cout << "\n*** Attempting to reduce the number of global "
<< "variables in the testcase\n";
unsigned OldSize = GVs.size();
ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs);
if (GVs.size() < OldSize)
BD.EmitProgressBytecode("reduced-global-variables");
}
}
}
}
// 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 && !BugpointIsInterrupted) {
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");
}
// 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 && !BugpointIsInterrupted) {
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 {
if (BugpointIsInterrupted) break;
--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 {
if (BugpointIsInterrupted) goto ExitLoops;
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);
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);
ExitLoops:
// Try to clean up the testcase by running funcresolve and globaldce...
if (!BugpointIsInterrupted) {
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...
} else {
delete M;
}
}
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(const std::string &ID) {
std::cout << "\n*** Debugging optimizer crash!\n";
// Reduce the list of passes which causes the optimizer to crash...
if (!BugpointIsInterrupted)
ReducePassList(*this).reduceList(PassesToRun);
std::cout << "\n*** Found crashing pass"
<< (PassesToRun.size() == 1 ? ": " : "es: ")
<< getPassesString(PassesToRun) << '\n';
EmitProgressBytecode(ID);
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);
}