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|
//===-- Searcher.cpp ------------------------------------------------------===//
//
// The KLEE Symbolic Virtual Machine
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "Searcher.h"
#include "CoreStats.h"
#include "ExecutionState.h"
#include "Executor.h"
#include "MergeHandler.h"
#include "PTree.h"
#include "StatsTracker.h"
#include "klee/ADT/DiscretePDF.h"
#include "klee/ADT/RNG.h"
#include "klee/Statistics/Statistics.h"
#include "klee/Module/InstructionInfoTable.h"
#include "klee/Module/KInstruction.h"
#include "klee/Module/KModule.h"
#include "klee/Support/ErrorHandling.h"
#include "klee/Support/ModuleUtil.h"
#include "klee/System/Time.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/CommandLine.h"
#include <cassert>
#include <climits>
#include <cmath>
#include <fstream>
using namespace klee;
using namespace llvm;
Searcher::~Searcher() {
}
///
ExecutionState &DFSSearcher::selectState() {
return *states.back();
}
void DFSSearcher::update(ExecutionState *current,
const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
states.insert(states.end(),
addedStates.begin(),
addedStates.end());
for (std::vector<ExecutionState *>::const_iterator it = removedStates.begin(),
ie = removedStates.end();
it != ie; ++it) {
ExecutionState *es = *it;
if (es == states.back()) {
states.pop_back();
} else {
bool ok = false;
for (std::vector<ExecutionState*>::iterator it = states.begin(),
ie = states.end(); it != ie; ++it) {
if (es==*it) {
states.erase(it);
ok = true;
break;
}
}
(void) ok;
assert(ok && "invalid state removed");
}
}
}
///
ExecutionState &BFSSearcher::selectState() {
return *states.front();
}
void BFSSearcher::update(ExecutionState *current,
const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
// Assumption: If new states were added KLEE forked, therefore states evolved.
// constraints were added to the current state, it evolved.
if (!addedStates.empty() && current &&
std::find(removedStates.begin(), removedStates.end(), current) ==
removedStates.end()) {
auto pos = std::find(states.begin(), states.end(), current);
assert(pos != states.end());
states.erase(pos);
states.push_back(current);
}
states.insert(states.end(),
addedStates.begin(),
addedStates.end());
for (std::vector<ExecutionState *>::const_iterator it = removedStates.begin(),
ie = removedStates.end();
it != ie; ++it) {
ExecutionState *es = *it;
if (es == states.front()) {
states.pop_front();
} else {
bool ok = false;
for (std::deque<ExecutionState*>::iterator it = states.begin(),
ie = states.end(); it != ie; ++it) {
if (es==*it) {
states.erase(it);
ok = true;
break;
}
}
(void) ok;
assert(ok && "invalid state removed");
}
}
}
///
ExecutionState &RandomSearcher::selectState() {
return *states[theRNG.getInt32()%states.size()];
}
void
RandomSearcher::update(ExecutionState *current,
const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
states.insert(states.end(),
addedStates.begin(),
addedStates.end());
for (std::vector<ExecutionState *>::const_iterator it = removedStates.begin(),
ie = removedStates.end();
it != ie; ++it) {
ExecutionState *es = *it;
__attribute__((unused))
bool ok = false;
for (std::vector<ExecutionState*>::iterator it = states.begin(),
ie = states.end(); it != ie; ++it) {
if (es==*it) {
states.erase(it);
ok = true;
break;
}
}
assert(ok && "invalid state removed");
}
}
///
WeightedRandomSearcher::WeightedRandomSearcher(WeightType type, RNG &rng)
: states(new DiscretePDF<ExecutionState*, ExecutionStateIDCompare>()),
theRNG{rng},
type(type) {
switch(type) {
case Depth:
case RP:
updateWeights = false;
break;
case InstCount:
case CPInstCount:
case QueryCost:
case MinDistToUncovered:
case CoveringNew:
updateWeights = true;
break;
default:
assert(0 && "invalid weight type");
}
}
WeightedRandomSearcher::~WeightedRandomSearcher() {
delete states;
}
ExecutionState &WeightedRandomSearcher::selectState() {
return *states->choose(theRNG.getDoubleL());
}
double WeightedRandomSearcher::getWeight(ExecutionState *es) {
switch(type) {
default:
case Depth:
return es->depth;
case RP:
return std::pow(0.5, es->depth);
case InstCount: {
uint64_t count = theStatisticManager->getIndexedValue(stats::instructions,
es->pc->info->id);
double inv = 1. / std::max((uint64_t) 1, count);
return inv * inv;
}
case CPInstCount: {
StackFrame &sf = es->stack.back();
uint64_t count = sf.callPathNode->statistics.getValue(stats::instructions);
double inv = 1. / std::max((uint64_t) 1, count);
return inv;
}
case QueryCost:
return (es->queryMetaData.queryCost.toSeconds() < .1)
? 1.
: 1. / es->queryMetaData.queryCost.toSeconds();
case CoveringNew:
case MinDistToUncovered: {
uint64_t md2u = computeMinDistToUncovered(es->pc,
es->stack.back().minDistToUncoveredOnReturn);
double invMD2U = 1. / (md2u ? md2u : 10000);
if (type==CoveringNew) {
double invCovNew = 0.;
if (es->instsSinceCovNew)
invCovNew = 1. / std::max(1, (int) es->instsSinceCovNew - 1000);
return (invCovNew * invCovNew + invMD2U * invMD2U);
} else {
return invMD2U * invMD2U;
}
}
}
}
void WeightedRandomSearcher::update(
ExecutionState *current, const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
if (current && updateWeights &&
std::find(removedStates.begin(), removedStates.end(), current) ==
removedStates.end())
states->update(current, getWeight(current));
for (std::vector<ExecutionState *>::const_iterator it = addedStates.begin(),
ie = addedStates.end();
it != ie; ++it) {
ExecutionState *es = *it;
states->insert(es, getWeight(es));
}
for (std::vector<ExecutionState *>::const_iterator it = removedStates.begin(),
ie = removedStates.end();
it != ie; ++it) {
states->remove(*it);
}
}
bool WeightedRandomSearcher::empty() {
return states->empty();
}
///
RandomPathSearcher::RandomPathSearcher(PTree &processTree, RNG &rng)
: processTree{processTree}, theRNG{rng}, idBitMask{processTree.getNextId()} {
}
RandomPathSearcher::~RandomPathSearcher() {
}
// Check if n is a valid pointer and a node belonging to us
#define IS_OUR_NODE_VALID(n) \
(((n).getPointer() != nullptr) && (((n).getInt() & idBitMask) != 0))
ExecutionState &RandomPathSearcher::selectState() {
unsigned flips=0, bits=0;
assert(processTree.root.getInt() & idBitMask &&
"Root should belong to the searcher");
PTreeNode *n = processTree.root.getPointer();
while (!n->state) {
if (!IS_OUR_NODE_VALID(n->left)) {
assert(IS_OUR_NODE_VALID(n->right) &&
"Both left and right nodes invalid");
assert(n != n->right.getPointer());
n = n->right.getPointer();
} else if (!IS_OUR_NODE_VALID(n->right)) {
assert(IS_OUR_NODE_VALID(n->left) && "Both right and left nodes invalid");
assert(n != n->left.getPointer());
n = n->left.getPointer();
} else {
if (bits==0) {
flips = theRNG.getInt32();
bits = 32;
}
--bits;
n = ((flips & (1 << bits)) ? n->left : n->right).getPointer();
}
}
return *n->state;
}
void
RandomPathSearcher::update(ExecutionState *current,
const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
for (auto es : addedStates) {
PTreeNode *pnode = es->ptreeNode, *parent = pnode->parent;
PTreeNodePtr *childPtr;
childPtr = parent ? ((parent->left.getPointer() == pnode) ? &parent->left
: &parent->right)
: &processTree.root;
while (pnode && !IS_OUR_NODE_VALID(*childPtr)) {
childPtr->setInt(childPtr->getInt() | idBitMask);
pnode = parent;
if (pnode)
parent = pnode->parent;
childPtr = parent
? ((parent->left.getPointer() == pnode) ? &parent->left
: &parent->right)
: &processTree.root;
}
}
for (auto es : removedStates) {
PTreeNode *pnode = es->ptreeNode, *parent = pnode->parent;
while (pnode && !IS_OUR_NODE_VALID(pnode->left) &&
!IS_OUR_NODE_VALID(pnode->right)) {
auto childPtr =
parent ? ((parent->left.getPointer() == pnode) ? &parent->left
: &parent->right)
: &processTree.root;
assert(IS_OUR_NODE_VALID(*childPtr) && "Removing pTree child not ours");
childPtr->setInt(childPtr->getInt() & ~idBitMask);
pnode = parent;
if (pnode)
parent = pnode->parent;
}
}
}
bool RandomPathSearcher::empty() {
return !IS_OUR_NODE_VALID(processTree.root);
}
///
MergingSearcher::MergingSearcher(Searcher *_baseSearcher)
: baseSearcher(_baseSearcher){}
MergingSearcher::~MergingSearcher() {
delete baseSearcher;
}
ExecutionState& MergingSearcher::selectState() {
assert(!baseSearcher->empty() && "base searcher is empty");
if (!UseIncompleteMerge)
return baseSearcher->selectState();
// Iterate through all MergeHandlers
for (auto cur_mergehandler: mergeGroups) {
// Find one that has states that could be released
if (!cur_mergehandler->hasMergedStates()) {
continue;
}
// Find a state that can be prioritized
ExecutionState *es = cur_mergehandler->getPrioritizeState();
if (es) {
return *es;
} else {
if (DebugLogIncompleteMerge){
llvm::errs() << "Preemptively releasing states\n";
}
// If no state can be prioritized, they all exceeded the amount of time we
// are willing to wait for them. Release the states that already arrived at close_merge.
cur_mergehandler->releaseStates();
}
}
// If we were not able to prioritize a merging state, just return some state
return baseSearcher->selectState();
}
///
BatchingSearcher::BatchingSearcher(Searcher *_baseSearcher,
time::Span _timeBudget,
unsigned _instructionBudget)
: baseSearcher(_baseSearcher),
timeBudget(_timeBudget),
instructionBudget(_instructionBudget),
lastState(0) {
}
BatchingSearcher::~BatchingSearcher() {
delete baseSearcher;
}
ExecutionState &BatchingSearcher::selectState() {
if (!lastState ||
(((timeBudget.toSeconds() > 0) &&
(time::getWallTime() - lastStartTime) > timeBudget)) ||
((instructionBudget > 0) &&
(stats::instructions - lastStartInstructions) > instructionBudget)) {
if (lastState) {
time::Span delta = time::getWallTime() - lastStartTime;
auto t = timeBudget;
t *= 1.1;
if (delta > t) {
klee_message("increased time budget from %f to %f\n", timeBudget.toSeconds(), delta.toSeconds());
timeBudget = delta;
}
}
lastState = &baseSearcher->selectState();
lastStartTime = time::getWallTime();
lastStartInstructions = stats::instructions;
return *lastState;
} else {
return *lastState;
}
}
void
BatchingSearcher::update(ExecutionState *current,
const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
if (std::find(removedStates.begin(), removedStates.end(), lastState) !=
removedStates.end())
lastState = 0;
baseSearcher->update(current, addedStates, removedStates);
}
/***/
IterativeDeepeningTimeSearcher::IterativeDeepeningTimeSearcher(Searcher *_baseSearcher)
: baseSearcher(_baseSearcher),
time(time::seconds(1)) {
}
IterativeDeepeningTimeSearcher::~IterativeDeepeningTimeSearcher() {
delete baseSearcher;
}
ExecutionState &IterativeDeepeningTimeSearcher::selectState() {
ExecutionState &res = baseSearcher->selectState();
startTime = time::getWallTime();
return res;
}
void IterativeDeepeningTimeSearcher::update(
ExecutionState *current, const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
const auto elapsed = time::getWallTime() - startTime;
if (!removedStates.empty()) {
std::vector<ExecutionState *> alt = removedStates;
for (std::vector<ExecutionState *>::const_iterator
it = removedStates.begin(),
ie = removedStates.end();
it != ie; ++it) {
ExecutionState *es = *it;
std::set<ExecutionState*>::const_iterator it2 = pausedStates.find(es);
if (it2 != pausedStates.end()) {
pausedStates.erase(it2);
alt.erase(std::remove(alt.begin(), alt.end(), es), alt.end());
}
}
baseSearcher->update(current, addedStates, alt);
} else {
baseSearcher->update(current, addedStates, removedStates);
}
if (current &&
std::find(removedStates.begin(), removedStates.end(), current) ==
removedStates.end() &&
elapsed > time) {
pausedStates.insert(current);
baseSearcher->removeState(current);
}
if (baseSearcher->empty()) {
time *= 2U;
klee_message("increased time budget to %f\n", time.toSeconds());
std::vector<ExecutionState *> ps(pausedStates.begin(), pausedStates.end());
baseSearcher->update(0, ps, std::vector<ExecutionState *>());
pausedStates.clear();
}
}
/***/
InterleavedSearcher::InterleavedSearcher(const std::vector<Searcher*> &_searchers)
: searchers(_searchers),
index(1) {
}
InterleavedSearcher::~InterleavedSearcher() {
for (std::vector<Searcher*>::const_iterator it = searchers.begin(),
ie = searchers.end(); it != ie; ++it)
delete *it;
}
ExecutionState &InterleavedSearcher::selectState() {
Searcher *s = searchers[--index];
if (index==0) index = searchers.size();
return s->selectState();
}
void InterleavedSearcher::update(
ExecutionState *current, const std::vector<ExecutionState *> &addedStates,
const std::vector<ExecutionState *> &removedStates) {
for (std::vector<Searcher*>::const_iterator it = searchers.begin(),
ie = searchers.end(); it != ie; ++it)
(*it)->update(current, addedStates, removedStates);
}
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