exprt dereference_rec(
const exprt &src,
const ssa_value_domaint &ssa_value_domain,
const std::string &nondet_prefix,
const namespacet &ns)
{
if(src.id()==ID_dereference)
{
const exprt &pointer=dereference_rec(
to_dereference_expr(src).pointer(),
ssa_value_domain,
nondet_prefix,
ns);
const typet &pointed_type=ns.follow(pointer.type().subtype());
const ssa_value_domaint::valuest values=ssa_value_domain(pointer, ns);
exprt result;
if(values.value_set.empty())
{
result=pointed_object(pointer, ns);
}
else
{
auto it=values.value_set.begin();
if(values.null || values.unknown ||
(values.value_set.size()>1 && it->type().get_bool("#dynamic")))
{
std::string dyn_type_name=pointed_type.id_string();
if(pointed_type.id()==ID_struct)
dyn_type_name+="_"+id2string(to_struct_type(pointed_type).get_tag());
irep_idt identifier="ssa::"+dyn_type_name+"_obj$unknown";
result=symbol_exprt(identifier, src.type());
result.set("#unknown_obj", true);
}
else
{
result=ssa_alias_value(src, (it++)->get_expr(), ns);
result.set("#heap_access", result.type().get_bool("#dynamic"));
}
for(; it!=values.value_set.end(); ++it)
{
exprt guard=ssa_alias_guard(src, it->get_expr(), ns);
exprt value=ssa_alias_value(src, it->get_expr(), ns);
result=if_exprt(guard, value, result);
result.set(
"#heap_access",
result.get_bool("#heap_access") ||
value.type().get_bool("#dynamic"));
}
}
return result;
}
else if(src.id()==ID_member)
{
member_exprt tmp=to_member_expr(src);
tmp.struct_op()=
dereference_rec(tmp.struct_op(), ssa_value_domain, nondet_prefix, ns);
tmp.set("#heap_access", tmp.struct_op().get_bool("#heap_access"));
#ifdef DEBUG
std::cout << "dereference_rec tmp: " << from_expr(ns, "", tmp) << '\n';
#endif
if(tmp.struct_op().is_nil())
return nil_exprt();
return lift_if(tmp);
}
else if(src.id()==ID_address_of)
{
address_of_exprt tmp=to_address_of_expr(src);
tmp.object()=
dereference_rec(tmp.object(), ssa_value_domain, nondet_prefix, ns);
tmp.set("#heap_access", tmp.object().get_bool("#heap_access"));
if(tmp.object().is_nil())
return nil_exprt();
return lift_if(tmp);
}
else
{
exprt tmp=src;
Forall_operands(it, tmp)
{
*it=dereference_rec(*it, ssa_value_domain, nondet_prefix, ns);
if(it->get_bool("#heap_access"))
tmp.set("#heap_access", true);
}
return tmp;
}
exprt dereference_rec(
const exprt &src,
const ssa_value_domaint &ssa_value_domain,
const std::string &nondet_prefix,
const namespacet &ns)
{
if(src.id()==ID_dereference)
{
const exprt &pointer=to_dereference_expr(src).pointer();
exprt pointer_deref=dereference(pointer, ssa_value_domain, nondet_prefix, ns);
// We use the identifier produced by
// local_SSAt::replace_side_effects_rec
exprt result=symbol_exprt(nondet_prefix, src.type());
// query the value sets
const ssa_value_domaint::valuest values=
ssa_value_domain(pointer, ns);
for(ssa_value_domaint::valuest::value_sett::const_iterator
it=values.value_set.begin();
it!=values.value_set.end();
it++)
{
exprt guard=ssa_alias_guard(src, it->get_expr(), ns);
exprt value=ssa_alias_value(src, it->get_expr(), ns);
result=if_exprt(guard, value, result);
}
return result;
}
else if(src.id()==ID_member)
{
member_exprt tmp=to_member_expr(src);
tmp.struct_op()=dereference_rec(tmp.struct_op(), ssa_value_domain, nondet_prefix, ns);
#ifdef DEBUG
std::cout << "dereference_rec tmp: " << from_expr(ns, "", tmp) << '\n';
#endif
if(tmp.struct_op().is_nil())
return nil_exprt();
return lift_if(tmp);
}
else if(src.id()==ID_address_of)
{
address_of_exprt tmp=to_address_of_expr(src);
tmp.object()=dereference_rec(tmp.object(), ssa_value_domain, nondet_prefix, ns);
if(tmp.object().is_nil())
return nil_exprt();
return lift_if(tmp);
}
else
{
exprt tmp=src;
Forall_operands(it, tmp)
*it=dereference_rec(*it, ssa_value_domain, nondet_prefix, ns);
return tmp;
}
}