bool sat_path_enumeratort::next(patht &path)
{
scratch_programt program(symbol_table);
program.append(fixed);
program.append(fixed);
// Let's make sure that we get a path we have not seen before.
for(std::list<distinguish_valuest>::iterator it=accelerated_paths.begin();
it!=accelerated_paths.end();
++it)
{
exprt new_path=false_exprt();
for(distinguish_valuest::iterator jt=it->begin();
jt!=it->end();
++jt)
{
exprt distinguisher=jt->first;
bool taken=jt->second;
if(taken)
{
not_exprt negated(distinguisher);
distinguisher.swap(negated);
}
or_exprt disjunct(new_path, distinguisher);
new_path.swap(disjunct);
}
program.assume(new_path);
}
program.add_instruction(ASSERT)->guard=false_exprt();
try
{
if(program.check_sat())
{
#ifdef DEBUG
std::cout << "Found a path" << std::endl;
#endif
build_path(program, path);
record_path(program);
return true;
}
}
catch(std::string s)
{
std::cout << "Error in fitting polynomial SAT check: " << s << std::endl;
}
catch(const char *s)
{
std::cout << "Error in fitting polynomial SAT check: " << s << std::endl;
}
return false;
}
void Suggester::kgram(string &w, vector<int>& collect) {
vector<vector<int>*> candidates;
unsigned sz = w.length();
for (int k = IndexWriter::MIN_N_GRAM; k <= IndexWriter::MAX_N_GRAM; ++k) {
for (unsigned n = 0; n < sz - 1; ++n) {
string gram = w.substr(n, k);
map<string, vector<int> >::iterator it = ir->grams.find(gram);
if (it != ir->grams.end()) {
candidates.push_back(&(it->second));
}
}
}
if (candidates.empty())
return;
vector<pair<int, int> > foo;
for (unsigned i = 0; i < candidates.size(); ++i) {
vector<pair<int, int> > bar;
for (unsigned j = 0; j < candidates[i]->size(); ++j) {
bar.push_back(make_pair(1, (*candidates[i])[j]));
}
disjunct(foo, bar, foo);
}
for (unsigned i = 0; i < foo.size(); ++i) {
pair<int, int> &p = foo[i];
// (sz - 1) means exact match
if (p.first >= static_cast<int>(sz) - 4) {
collect.push_back(p.second);
}
}
}
TEST(RuleBody, Basic) {
RuleBody body;
// start with an A
auto a = RuleBody::atom(new AstAtom("A"));
EXPECT_EQ("A()", toString(a));
a.conjunct(RuleBody::atom(new AstAtom("B")));
EXPECT_EQ("A(),B()", toString(a));
a.disjunct(RuleBody::atom(new AstAtom("C")));
EXPECT_EQ("A(),B();C()", toString(a));
}
bool disjunctive_polynomial_accelerationt::fit_polynomial(
exprt &var,
polynomialt &polynomial,
patht &path) {
// These are the variables that var depends on with respect to the body.
std::vector<expr_listt> parameters;
std::set<std::pair<expr_listt, exprt> > coefficients;
expr_listt exprs;
scratch_programt program(symbol_table);
expr_sett influence;
cone_of_influence(var, influence);
#ifdef DEBUG
std::cout << "Fitting a polynomial for " << expr2c(var, ns) << ", which depends on:"
<< std::endl;
for (expr_sett::iterator it = influence.begin();
it != influence.end();
++it) {
std::cout << expr2c(*it, ns) << std::endl;
}
#endif
for (expr_sett::iterator it = influence.begin();
it != influence.end();
++it) {
if (it->id() == ID_index ||
it->id() == ID_dereference) {
// Hack: don't accelerate anything that depends on an array
// yet...
return false;
}
exprs.clear();
exprs.push_back(*it);
parameters.push_back(exprs);
exprs.push_back(loop_counter);
parameters.push_back(exprs);
}
// N
exprs.clear();
exprs.push_back(loop_counter);
parameters.push_back(exprs);
// N^2
exprs.push_back(loop_counter);
parameters.push_back(exprs);
// Constant
exprs.clear();
parameters.push_back(exprs);
for (std::vector<expr_listt>::iterator it = parameters.begin();
it != parameters.end();
++it) {
symbolt coeff = utils.fresh_symbol("polynomial::coeff", signed_poly_type());
coefficients.insert(make_pair(*it, coeff.symbol_expr()));
// XXX HACK HACK HACK
// I'm just constraining these coefficients to prevent overflows messing things
// up later... Should really do this properly somehow.
program.assume(binary_relation_exprt(from_integer(-(1 << 10), signed_poly_type()),
"<", coeff.symbol_expr()));
program.assume(binary_relation_exprt(coeff.symbol_expr(), "<",
from_integer(1 << 10, signed_poly_type())));
}
// Build a set of values for all the parameters that allow us to fit a
// unique polynomial.
std::map<exprt, exprt> ivals1;
std::map<exprt, exprt> ivals2;
std::map<exprt, exprt> ivals3;
for (expr_sett::iterator it = influence.begin();
it != influence.end();
++it) {
symbolt ival1 = utils.fresh_symbol("polynomial::init",
it->type());
symbolt ival2 = utils.fresh_symbol("polynomial::init",
it->type());
symbolt ival3 = utils.fresh_symbol("polynomial::init",
it->type());
program.assume(binary_relation_exprt(ival1.symbol_expr(), "<",
ival2.symbol_expr()));
program.assume(binary_relation_exprt(ival2.symbol_expr(), "<",
ival3.symbol_expr()));
#if 0
if (it->type() == signedbv_typet()) {
program.assume(binary_relation_exprt(ival1.symbol_expr(), ">",
from_integer(-100, it->type())));
}
program.assume(binary_relation_exprt(ival1.symbol_expr(), "<",
from_integer(100, it->type())));
if (it->type() == signedbv_typet()) {
program.assume(binary_relation_exprt(ival2.symbol_expr(), ">",
from_integer(-100, it->type())));
}
program.assume(binary_relation_exprt(ival2.symbol_expr(), "<",
from_integer(100, it->type())));
if (it->type() == signedbv_typet()) {
program.assume(binary_relation_exprt(ival3.symbol_expr(), ">",
from_integer(-100, it->type())));
}
program.assume(binary_relation_exprt(ival3.symbol_expr(), "<",
from_integer(100, it->type())));
#endif
ivals1[*it] = ival1.symbol_expr();
ivals2[*it] = ival2.symbol_expr();
ivals3[*it] = ival3.symbol_expr();
//ivals1[*it] = from_integer(1, it->type());
}
std::map<exprt, exprt> values;
for (expr_sett::iterator it = influence.begin();
it != influence.end();
++it) {
values[*it] = ivals1[*it];
}
// Start building the program. Begin by decl'ing each of the
// master distinguishers.
for (std::list<exprt>::iterator it = distinguishers.begin();
it != distinguishers.end();
++it) {
program.add_instruction(DECL)->code = code_declt(*it);
}
// Now assume our polynomial fits at each of our sample points.
assert_for_values(program, values, coefficients, 1, fixed, var);
for (int n = 0; n <= 1; n++) {
for (expr_sett::iterator it = influence.begin();
it != influence.end();
++it) {
values[*it] = ivals2[*it];
assert_for_values(program, values, coefficients, n, fixed, var);
values[*it] = ivals3[*it];
assert_for_values(program, values, coefficients, n, fixed, var);
values[*it] = ivals1[*it];
}
}
for (expr_sett::iterator it = influence.begin();
it != influence.end();
++it) {
values[*it] = ivals3[*it];
}
assert_for_values(program, values, coefficients, 0, fixed, var);
assert_for_values(program, values, coefficients, 1, fixed, var);
assert_for_values(program, values, coefficients, 2, fixed, var);
// Let's make sure that we get a path we have not seen before.
for (std::list<distinguish_valuest>::iterator it = accelerated_paths.begin();
it != accelerated_paths.end();
++it) {
exprt new_path = false_exprt();
for (distinguish_valuest::iterator jt = it->begin();
jt != it->end();
++jt) {
exprt distinguisher = jt->first;
bool taken = jt->second;
if (taken) {
not_exprt negated(distinguisher);
distinguisher.swap(negated);
}
or_exprt disjunct(new_path, distinguisher);
new_path.swap(disjunct);
}
program.assume(new_path);
}
utils.ensure_no_overflows(program);
// Now do an ASSERT(false) to grab a counterexample
program.add_instruction(ASSERT)->guard = false_exprt();
// If the path is satisfiable, we've fitted a polynomial. Extract the
// relevant coefficients and return the expression.
try {
if (program.check_sat()) {
#ifdef DEBUG
std::cout << "Found a polynomial" << std::endl;
#endif
utils.extract_polynomial(program, coefficients, polynomial);
build_path(program, path);
record_path(program);
return true;
}
} catch (std::string s) {
std::cout << "Error in fitting polynomial SAT check: " << s << std::endl;
} catch (const char *s) {
std::cout << "Error in fitting polynomial SAT check: " << s << std::endl;
}
return false;
}
static
void replaceAssertVertex(NGWrapper &g, NFAVertex t, edge_cache_t &edge_cache,
u32 &assert_edge_count) {
DEBUG_PRINTF("replacing assert vertex %u\n", g[t].index);
const u32 flags = g[t].assert_flags;
DEBUG_PRINTF("consider assert vertex %u with flags %u\n",
g[t].index, flags);
// Wire up all the predecessors to all the successors.
for (const auto &inEdge : in_edges_range(t, g)) {
NFAVertex u = source(inEdge, g);
if (u == t) {
continue; // ignore self-loops
}
const u32 flags_inc_in = conjunct(g[inEdge].assert_flags,
flags);
if (flags_inc_in == DEAD_EDGE) {
DEBUG_PRINTF("fail, in-edge has bad flags %d\n",
g[inEdge].assert_flags);
continue;
}
for (const auto &outEdge : out_edges_range(t, g)) {
NFAVertex v = target(outEdge, g);
DEBUG_PRINTF("consider path [%u,%u,%u]\n", g[u].index,
g[t].index, g[v].index);
if (v == t) {
continue; // ignore self-loops
}
const u32 flags_final = conjunct(g[outEdge].assert_flags,
flags_inc_in);
if (flags_final == DEAD_EDGE) {
DEBUG_PRINTF("fail, out-edge has bad flags %d\n",
g[outEdge].assert_flags);
continue;
}
if ((g[u].assert_flags & POS_FLAG_MULTILINE_START)
&& v == g.acceptEod) {
DEBUG_PRINTF("fail, (?m)^ does not match \\n at eod\n");
continue;
}
/* Replace path (u,t,v) with direct edge (u,v), unless the edge
* already exists, in which case we just need to edit its
* properties.
*
* Use edge_cache to prevent us going O(N).
*/
auto cache_key = make_pair(u, v);
auto ecit = edge_cache.find(cache_key);
if (ecit == edge_cache.end()) {
DEBUG_PRINTF("adding edge %u %u\n", g[u].index,
g[v].index);
NFAEdge e = add_edge(u, v, g).first;
edge_cache.emplace(cache_key, e);
g[e].assert_flags = flags;
if (++assert_edge_count > MAX_ASSERT_EDGES) {
throw CompileError(g.expressionIndex,
"Pattern is too large.");
}
} else {
NFAEdge e = ecit->second;
DEBUG_PRINTF("updating edge %u %u [a %u]\n", g[u].index,
g[v].index, g[t].index);
// Edge already exists.
u32 &e_flags = g[e].assert_flags;
e_flags = disjunct(e_flags, flags_final);
assert(e_flags != DEAD_EDGE);
}
}
}
// Clear vertex t to remove all the old edges.
/* no need to clear the cache, as we will never look up its edge as it is
* unreachable */
clear_vertex(t, g);
}
