bool
Reducer::is_ptr_written_in_stm(const Statement* stm)
{
size_t i;
FactMgr* fm = get_fact_mgr_for_func(stm->func);
const vector<const Variable *>& write_vars = fm->map_stm_effect[stm].get_write_vars();
for (i=0; i<write_vars.size(); i++) {
const Variable* wvar = write_vars[i];
if (wvar->is_pointer()) {
const Block* blk = (stm->eType == eBlock) ? (const Block*)stm : stm->parent;
if (wvar->is_visible(blk) && is_var_used(wvar)) {
return true;
}
}
}
return false;
}
ExpressionVariable *
ExpressionVariable::make_random(CGContext &cg_context, const Type* type, const CVQualifiers* qfer, bool as_param, bool as_return)
{
DEPTH_GUARD_BY_TYPE_RETURN(dtExpressionVariable, NULL);
Function *curr_func = cg_context.get_current_func();
FactMgr* fm = get_fact_mgr_for_func(curr_func);
vector<const Variable*> dummy;
// save current effects, in case we need to reset
Effect eff_accum = cg_context.get_accum_effect();
Effect eff_stmt = cg_context.get_effect_stm();
ExpressionVariable *ev = 0;
do {
const Variable* var = 0;
// try to use one of must_read_vars in CGContext
var = VariableSelector::select_must_use_var(Effect::READ, cg_context, type, qfer);
if (var == NULL) {
var = VariableSelector::select(Effect::READ, cg_context, type, qfer, dummy, eFlexible);
}
ERROR_GUARD(NULL);
if (!var)
continue;
if (!type->is_float() && var->type->is_float())
continue;
// forbid a parameter to take the address of an argument
// this is to simplify the path shortcutting delta
if (as_param && var->is_argument() && var->type->is_dereferenced_from(type)) {
continue;
}
if (!CGOptions::addr_taken_of_locals()
&& var->type->is_dereferenced_from(type)
&& (var->is_argument() || var->is_local())) {
continue;
}
// forbid a escaping pointer to take the address of an argument or a local variable
int indirection = var->type->get_indirect_level() - type->get_indirect_level();
if (as_return && CGOptions::no_return_dead_ptr() &&
FactPointTo::is_pointing_to_locals(var, cg_context.get_current_block(), indirection, fm->global_facts)) {
continue;
}
int valid = FactPointTo::opportunistic_validate(var, type, fm->global_facts);
if (valid) {
ExpressionVariable tmp(*var, type);
if (tmp.visit_facts(fm->global_facts, cg_context)) {
ev = tmp.get_indirect_level() == 0 ? new ExpressionVariable(*var) : new ExpressionVariable(*var, type);
cg_context.curr_blk = cg_context.get_current_block();
break;
}
else {
cg_context.reset_effect_accum(eff_accum);
cg_context.reset_effect_stm(eff_stmt);
}
}
dummy.push_back(var);
} while (true);
// statistics
int deref_level = ev->get_indirect_level();
if (deref_level > 0) {
incr_counter(Bookkeeper::read_dereference_cnts, deref_level);
}
if (deref_level < 0) {
Bookkeeper::record_address_taken(ev->get_var());
}
Bookkeeper::record_volatile_access(ev->get_var(), deref_level, false);
return ev;
}
