bool state_projectiont::is_new(const statet &state, bool use_cache)
{
// get the right map
assert(!state.data().previous.is_null());
state_listt &state_list=
state_map[state.data().previous_PC];
// first try syntactically
for(state_listt::const_iterator
it=state_list.begin();
it!=state_list.end();
it++)
if(is_syntactically_equal(*it, state))
return false; // not new
// now try expensive comparison
for(state_listt::const_iterator
it=state_list.begin();
it!=state_list.end();
it++)
if(is_equal(*it, state, use_cache))
{
// put into list anyways
state_list.push_back(state);
return false; // not new
}
// not found, it's new
state_list.push_back(state);
return true;
}
void simulator_ctt::compute_goto_successors(
const statet &state,
queuet &queue)
{
const instructiont &instruction=*state.data().threads.front().PC;
unsigned count=0;
// must have target
assert(!instruction.targets.empty());
formulat instantiated_guard=
instantiate(state, 0, instruction.guard);
formulat new_guard_taken;
if(instantiated_guard.is_true())
new_guard_taken=state.data().guard;
else
{
new_guard_taken=formula_container.gen_and(
instantiated_guard,
state.data().guard);
formulat new_guard_not_taken=formula_container.gen_and(
formula_container.gen_not(instantiated_guard),
state.data().guard);
// do "guard is false" case
statet new_state=state;
new_state.data_w().threads.front().PC++;
new_state.data_w().guard=new_guard_not_taken;
new_state.data_w().taken=false;
new_state.set_previous(state, 0);
queue.add(new_state);
count++;
}
for(program_formulat::formula_goto_programt::
instructiont::targetst::const_iterator
t_it=instruction.targets.begin();
t_it!=instruction.targets.end();
t_it++)
{
statet new_state=state;
new_state.data_w().threads.front().PC=*t_it;
new_state.data_w().guard=new_guard_taken;
new_state.data_w().taken=true;
new_state.set_previous(state, 0);
queue.add(new_state);
count++;
}
if(count>=2) path_counter+=count-1;
}
void simulatort::explore(
const statet &state,
queuet &queue)
{
#ifdef DEBUG
std::cout << "simulatort::explore1\n";
#endif
#if 0
std::cout << "/////////////////////////////////////////////// "
<< "\n";
for(unsigned thread=0; thread<program_formula.threads.size(); thread++)
{
std::cout << "Thread " << thread << " Location: ";
if(state.data().PCs[thread]==
program_formula.threads[thread].formula_goto_program.instructions.end())
std::cout << "END" << std::endl;
else
{
instructiont &instruction=*state.data().PCs[thread];
std::cout << location_string(instruction.location) << std::endl;
}
}
std::cout << std::endl;
#endif
// dump it if the guard is false
if(state.data().guard.is_false())
return;
#ifdef DEBUG
std::cout << "simulatort::explore2\n";
#endif
if(history.check_history(
state, enable_qbf_cache, enable_small_history))
{
// we have seen it already
#ifdef DEBUG
std::cout << ">>>>>>>>>>>>>>>>>>>>>>>> SEEN ALREADY\n";
#endif
return;
}
#ifdef DEBUG
std::cout << "simulatort::explore3\n";
#endif
compute_successor_states(state, true, queue);
#ifdef DEBUG
std::cout << "simulatort::explore4\n";
#endif
}
bool state_projectiont::is_syntactically_equal(
const statet &old_state,
const statet &new_state)
{
if(old_state.data().guard!=new_state.data().guard)
return false;
unsigned v=0;
for(program_formulat::variablest::const_iterator
it=program_formula.variables.begin();
it!=program_formula.variables.end();
it++, v++)
{
if(it->is_global)
{
assert(v<old_state.data().globals.size());
assert(v<new_state.data().globals.size());
if(old_state.data().globals[v]!=
new_state.data().globals[v])
return false;
}
}
return true;
}
void simulator_ctt::execute_assert(
statet &state,
const program_formulat::formula_goto_programt::instructiont &instruction)
{
std::cout << "CHECKING ASSERTION\n";
formulat condition=
instantiate(state, 0, instruction.guard);
formulat property=
formula_container.gen_and(
state.data().guard,
formula_container.gen_not(condition));
// see if it is reachable
if(!property.is_false() &&
is_satisfiable(property))
{
tracet trace;
compute_trace(state, trace, true);
dump_trace(trace, instruction);
std::cout << "Assertion violated" << std::endl;
std::cout << std::endl;
error_state_found=true;
}
#if 0
else
{
// otherwise, treat this like an assumption
state.data_w().guard=
formula_container.gen_and(state.data().guard, condition);
}
#endif
}
void simulator_ctt::execute_functioncall(
const statet &state,
edget &edge)
{
const program_formulat::formula_goto_programt::instructiont
&instruction=*state.data().threads.front().PC;
const irep_idt &function_id=instruction.code.function;
// find in program formula
program_formulat::function_mapt::const_iterator
f_it=program_formula.function_map.find(function_id);
assert(f_it!=program_formula.function_map.end());
const program_formulat::functiont &f=f_it->second;
// produce a start state
statet start_state(state);
statet::threadt &thread=start_state.data_w().threads.back();
// adjust PC
thread.program=&(f.body);
thread.PC=thread.start_pc();
// assign args
assert(instruction.code.function_args.size()==f.args.size());
for(unsigned i=0; i<f.args.size(); i++)
{
formulat formula=instruction.code.function_args[i];
formula=instantiate(state, 0, formula);
start_state.data_w().set_var(f.args[i], 0, formula);
}
std::cout << "Adding edge for " << function_id << std::endl;
// add edge
edget &f_edge=new_edge(function_id, start_state);
f_edge.calls.push_back(conft(edge, state));
}
void simulator_ctt::execute_return(const statet &state, edget &edge)
{
// compute vector of return values
std::vector<formulat> return_values;
bool have_return=!state.data().threads.front().is_at_end();
if(have_return)
{
const program_formulat::formula_goto_programt::instructiont
&return_instruction=*state.data().threads.front().PC;
return_values.resize(return_instruction.code.assigns.size());
for(unsigned i=0; i<return_values.size(); i++)
{
formulat f1=return_instruction.code.assigns[i].value;
formulat f2=instantiate(state, 0, f1);
return_values[i]=f2;
}
}
// propagate to all call sites
for(callst::const_iterator it=edge.calls.begin();
it!=edge.calls.end();
it++)
{
const conft &conf=*it;
// save PC
const_targett PC=conf.state.data().threads.front().PC;
const program_formulat::formula_goto_programt::instructiont
&call_instruction=*PC;
// get return PC
PC++;
statet new_state=state;
// set PC to return location
new_state.data_w().threads.front().PC=PC;
new_state.data_w().threads.front().program=
conf.state.data().threads.front().program;
if(!call_instruction.code.function_lhs.empty())
{
if(have_return)
{
assert(call_instruction.code.function_lhs.size()==
return_values.size());
// do return value
for(unsigned i=0; i<return_values.size(); i++)
{
if(call_instruction.code.function_lhs[i].in_use)
{
unsigned lhs=call_instruction.code.function_lhs[i].variable;
new_state.data_w().set_var(lhs, 0, return_values[i]);
}
}
}
}
std::cout << "Adding to queue of " << conf.edge->function << std::endl;
// put it into the right queue
conf.edge->queue.add(new_state);
// make sure this is noticed
active_edges.insert(conf.edge);
}
}
bool match(
formula_containert &container,
const statet &state,
const std::map<vart, bool> &values)
{
// do the reset
container.reset_prop();
// build the SAT instance
satcheckt satcheck;
// 1st, the guard must hold
{
literalt l=state.data().guard.convert(satcheck);
satcheck.l_set_to(l, true);
}
#if 0
std::cout << "G: ";
state.data().guard.output(std::cout);
std::cout << std::endl;
#endif
// 2nd, the values must match
for(std::map<vart, bool>::const_iterator
it=values.begin();
it!=values.end();
it++)
{
const vart &var=it->first;
formulat f=state.data().get_var(var.var_nr, var.thread_nr);
literalt l=f.convert(satcheck);
satcheck.l_set_to(l, it->second);
#if 0
std::cout << "V: ";
state.data().values[v].output(std::cout);
std::cout << std::endl;
#endif
}
std::cout << "Running " << satcheck.solver_text() << ", "
<< satcheck.no_variables() << " variables, "
<< satcheck.no_clauses() << " clauses" << std::endl;
switch(satcheck.prop_solve())
{
case propt::P_SATISFIABLE:
// oh! match!
return true;
case propt::P_UNSATISFIABLE:
// nah, no match
return false;
default:;
assert(false);
}
assert(false);
return false;
}