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add a predicate for depth limit assumptions

This commit is contained in:
Simon Cruanes 2017-12-06 13:01:54 +01:00
parent d5e134dd94
commit 06e0b12700
3 changed files with 67 additions and 2 deletions

View file

@ -342,7 +342,7 @@ namespace recfun {
*/
util::util(ast_manager & m, family_id id)
: m_manager(m), m_family_id(id), m_th_rw(m), m_plugin(0) {
: m_manager(m), m_family_id(id), m_th_rw(m), m_plugin(0), m_dlimit_map() {
m_plugin = dynamic_cast<decl::plugin*>(m.get_plugin(m_family_id));
}
@ -354,6 +354,15 @@ namespace recfun {
d.set_definition(n_vars, vars, rhs);
}
// get or create predicate for depth limit
depth_limit_pred_ref util::get_depth_limit_pred(unsigned d) {
depth_limit_pred * pred = nullptr;
if (! m_dlimit_map.find(d, pred)) {
pred = alloc(depth_limit_pred, m(), m_family_id, d);
m_dlimit_map.insert(d, pred);
}
return depth_limit_pred_ref(pred, *this);
}
// used to know which `app` are from this theory
struct is_imm_pred : is_immediate_pred {
@ -387,6 +396,17 @@ namespace recfun {
d->compute_cases(is_i, u->get_th_rewriter(), n_vars, vars, rhs);
}
depth_limit_pred::depth_limit_pred(ast_manager & m, family_id fid, unsigned d)
: m_name_buf(), m_name(""), m_depth(d), m_decl(m) {
// build name, then build decl
std::ostringstream tmpname(m_name_buf);
tmpname << "depth_limit_" << d;
m_name = symbol(m_name_buf.c_str());
parameter params[1] = { parameter(d) };
func_decl_info info(fid, OP_DEPTH_LIMIT, 1, params);
m_decl = m.mk_func_decl(m_name, 0, ((sort*const *)nullptr), m.mk_bool_sort(), info);
}
namespace decl {
plugin::plugin() : decl_plugin(), m_defs(), m_case_defs(), m_def_block() {}
plugin::~plugin() { finalize(); }
@ -424,6 +444,13 @@ namespace recfun {
}
}
app_ref plugin::mk_depth_limit_pred(unsigned d) {
depth_limit_pred_ref p = u().get_depth_limit_pred(d);
app_ref res(m());
m().mk_app(p->get_decl(), 0, nullptr, res);
return res;
}
def* plugin::mk_def(symbol const& name, unsigned n, sort ** params, sort * range,
unsigned n_vars, var ** vars, expr * rhs) {
SASSERT(! m_defs.contains(name));

View file

@ -30,6 +30,7 @@ namespace recfun {
enum op_kind {
OP_FUN_DEFINED, // defined function with one or more cases, possibly recursive
OP_FUN_CASE_PRED, // predicate guarding a given control flow path
OP_DEPTH_LIMIT, // predicate enforcing some depth limit
};
/*! A predicate `p(t1…tn)`, that, if true, means `f(t1…tn)` is following
@ -145,6 +146,27 @@ namespace recfun {
def * get_def() const { return d; }
};
// predicate for limiting unrolling depth, to be used in assumptions and conflicts
class depth_limit_pred {
friend class util;
std::string m_name_buf;
symbol m_name;
unsigned m_depth;
func_decl_ref m_decl;
unsigned m_refcount;
void inc_ref() { m_refcount ++; }
void dec_ref() { SASSERT(m_refcount > 0); m_refcount --; }
public:
depth_limit_pred(ast_manager & m, family_id fid, unsigned d);
unsigned get_depth() const { return m_depth; }
symbol const & get_name() const { return m_name; }
func_decl * get_decl() const { return m_decl.get(); }
};
// A reference to `depth_limit_pred`
typedef obj_ref<depth_limit_pred, util> depth_limit_pred_ref;
namespace decl {
class plugin : public decl_plugin {
@ -186,6 +208,7 @@ namespace recfun {
bool has_case_def(const symbol& s) const { return m_case_defs.contains(s); }
case_def& get_case_def(symbol const& s) { SASSERT(has_case_def(s)); return *(m_case_defs[s]); }
bool is_declared(symbol const& s) const { return m_defs.contains(s); }
app_ref mk_depth_limit_pred(unsigned d);
private:
func_decl * mk_fun_pred_decl(unsigned num_parameters, parameter const * parameters,
unsigned arity, sort * const * domain, sort * range);
@ -198,11 +221,14 @@ namespace recfun {
// Varus utils for recursive functions
class util {
friend class decl::plugin;
typedef map<int, depth_limit_pred *, int_hash, default_eq<int>> depth_limit_map;
ast_manager & m_manager;
family_id m_family_id;
th_rewriter m_th_rw;
decl::plugin * m_plugin;
depth_limit_map m_dlimit_map;
bool compute_is_immediate(expr * rhs);
void set_definition(promise_def & d, unsigned n_vars, var * const * vars, expr * rhs);
@ -237,10 +263,22 @@ namespace recfun {
app* mk_case_pred(case_pred const & p, ptr_vector<expr> const & args) {
return m().mk_app(p.get_decl(), args.size(), args.c_ptr());
}
void inc_ref(depth_limit_pred * p) { p->inc_ref(); }
void dec_ref(depth_limit_pred * p) {
p->dec_ref();
if (p->m_refcount == 0) {
m_dlimit_map.remove(p->m_depth);
dealloc(p);
}
}
depth_limit_pred_ref get_depth_limit_pred(unsigned d);
};
}
typedef recfun::def recfun_def;
typedef recfun::case_def recfun_case_def;
typedef recfun::depth_limit_pred recfun_depth_limit_pred;
typedef recfun::decl::plugin recfun_decl_plugin;
typedef recfun::util recfun_util;

View file

@ -261,7 +261,7 @@ struct smt_params : public preprocessor_params,
m_display_features(false),
m_new_core2th_eq(true),
m_ematching(true),
m_recfun_max_depth(500),
m_recfun_max_depth(50),
m_case_split_strategy(CS_ACTIVITY_DELAY_NEW),
m_rel_case_split_order(0),
m_lookahead_diseq(false),