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llvm-6502/tools/bugpoint/CrashDebugger.cpp
Owen Anderson 0a5372ed3e Begin the painful process of tearing apart the rat'ss nest that is Constants.cpp and ConstantFold.cpp. 
This involves temporarily hard wiring some parts to use the global context.  This isn't ideal, but it's
the only way I could figure out to make this process vaguely incremental.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75445 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-13 04:09:18 +00:00

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//===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file 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/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/ValueSymbolTable.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/Verifier.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));
cl::opt<bool>
NoGlobalRM ("disable-global-remove",
cl::desc("Do not remove global variables"),
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(), BD.getContext());
if (BD.Program == 0) {
std::cerr << BD.getToolName() << ": Error reading bitcode 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...
DenseMap<const Value*, Value*> ValueMap;
Module *M = CloneModule(BD.getProgram(), ValueMap);
// Convert list to set for fast lookup...
std::set<GlobalVariable*> GVSet;
for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
GlobalVariable* CMGV = cast<GlobalVariable>(ValueMap[GVs[i]]);
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() && !GVSet.count(I)) {
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()->getFunction("main")) == Funcs.end())
return false;
// Clone the program to try hacking it apart...
DenseMap<const Value*, Value*> ValueMap;
Module *M = CloneModule(BD.getProgram(), ValueMap);
// Convert list to set for fast lookup...
std::set<Function*> Functions;
for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
Function *CMF = cast<Function>(ValueMap[Funcs[i]]);
assert(CMF && "Function not in module?!");
assert(CMF->getFunctionType() == Funcs[i]->getFunctionType() && "wrong ty");
assert(CMF->getName() == Funcs[i]->getName() && "wrong name");
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->isDeclaration() && !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...
DenseMap<const Value*, Value*> ValueMap;
Module *M = CloneModule(BD.getProgram(), ValueMap);
// Convert list to set for fast lookup...
SmallPtrSet<BasicBlock*, 8> Blocks;
for (unsigned i = 0, e = BBs.size(); i != e; ++i)
Blocks.insert(cast<BasicBlock>(ValueMap[BBs[i]]));
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);
TerminatorInst *BBTerm = BB->getTerminator();
if (isa<StructType>(BBTerm->getType()))
BBTerm->replaceAllUsesWith(UndefValue::get(BBTerm->getType()));
else if (BB->getTerminator()->getType() != Type::VoidTy)
BBTerm->replaceAllUsesWith(
BD.getContext().getNullValue(BBTerm->getType()));
// Replace the old terminator instruction.
BB->getInstList().pop_back();
new UnreachableInst(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 (SmallPtrSet<BasicBlock*, 8>::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) {
ValueSymbolTable &ST = BlockInfo[i].first->getValueSymbolTable();
Value* V = ST.lookup(BlockInfo[i].second);
if (V && V->getType() == Type::LabelTy)
BBs.push_back(cast<BasicBlock>(V));
}
return true;
}
delete M; // It didn't crash, try something else.
return false;
}
namespace {
/// ReduceCrashingInstructions reducer - This works by removing the specified
/// non-terminator instructions and replacing them with undef.
///
class ReduceCrashingInstructions : public ListReducer<const Instruction*> {
BugDriver &BD;
bool (*TestFn)(BugDriver &, Module *);
public:
ReduceCrashingInstructions(BugDriver &bd, bool (*testFn)(BugDriver &,
Module *))
: BD(bd), TestFn(testFn) {}
virtual TestResult doTest(std::vector<const Instruction*> &Prefix,
std::vector<const Instruction*> &Kept) {
if (!Kept.empty() && TestInsts(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestInsts(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestInsts(std::vector<const Instruction*> &Prefix);
};
}
bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
&Insts) {
// Clone the program to try hacking it apart...
DenseMap<const Value*, Value*> ValueMap;
Module *M = CloneModule(BD.getProgram(), ValueMap);
// Convert list to set for fast lookup...
SmallPtrSet<Instruction*, 64> Instructions;
for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
assert(!isa<TerminatorInst>(Insts[i]));
Instructions.insert(cast<Instruction>(ValueMap[Insts[i]]));
}
std::cout << "Checking for crash with only " << Instructions.size();
if (Instructions.size() == 1)
std::cout << " instruction: ";
else
std::cout << " instructions: ";
for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
Instruction *Inst = I++;
if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst)) {
if (Inst->getType() != Type::VoidTy)
Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
Inst->eraseFromParent();
}
}
// Verify that this is still valid.
PassManager Passes;
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 instruction pointers that point into the now-current
// module, and that they don't include any deleted blocks.
Insts.clear();
for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
E = Instructions.end(); I != E; ++I)
Insts.push_back(*I);
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 (!NoGlobalRM &&
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.EmitProgressBitcode("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->isDeclaration())
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.EmitProgressBitcode("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);
unsigned OldSize = Blocks.size();
ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode("reduced-blocks");
}
// Attempt to delete instructions using bisection. This should help out nasty
// cases with large basic blocks where the problem is at one end.
if (!BugpointIsInterrupted) {
std::vector<const Instruction*> Insts;
for (Module::const_iterator MI = BD.getProgram()->begin(),
ME = BD.getProgram()->end(); MI != ME; ++MI)
for (Function::const_iterator FI = MI->begin(), FE = MI->end(); FI != FE;
++FI)
for (BasicBlock::const_iterator I = FI->begin(), E = FI->end();
I != E; ++I)
if (!isa<TerminatorInst>(I))
Insts.push_back(I);
ReduceCrashingInstructions(BD, TestFn).reduceList(Insts);
}
// 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->isDeclaration())
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;
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.EmitProgressBitcode("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';
EmitProgressBitcode(ID);
return DebugACrash(*this, TestForOptimizerCrash);
}
static bool TestForCodeGenCrash(BugDriver &BD, Module *M) {
try {
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);
}
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