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WIP add axioms

This commit is contained in:
Murphy Berzish 2015-09-26 18:51:02 -04:00
parent 992fff8ba8
commit 4d5a0ea53f
4 changed files with 120 additions and 40 deletions

View file

@ -25,7 +25,10 @@ str_decl_plugin::str_decl_plugin():
m_strv_sym("String"),
m_str_decl(0),
m_concat_decl(0),
m_length_decl(0){
m_length_decl(0),
m_arith_plugin(0),
m_arith_fid(0),
m_int_sort(0){
}
str_decl_plugin::~str_decl_plugin(){
@ -45,7 +48,11 @@ void str_decl_plugin::set_manager(ast_manager * m, family_id id) {
m->inc_ref(m_str_decl);
sort * s = m_str_decl;
SASSERT(m_manager->has_plugin(symbol("arith")));
m_arith_fid = m_manager->mk_family_id("arith");
m_arith_plugin = static_cast<arith_decl_plugin*>(m_manager->get_plugin(m_arith_fid));
SASSERT(m_arith_plugin);
m_int_sort = m_manager->mk_sort(m_arith_fid, INT_SORT);
SASSERT(m_int_sort != 0); // arith_decl_plugin must be installed before str_decl_plugin.
m_manager->inc_ref(m_int_sort);

View file

@ -37,6 +37,7 @@ protected:
symbol m_strv_sym;
sort * m_str_decl;
arith_decl_plugin * m_arith_plugin;
sort * m_int_sort;
family_id m_arith_fid;

View file

@ -34,22 +34,25 @@ theory_str::theory_str(ast_manager & m):
theory_str::~theory_str() {
}
void theory_str::assert_axiom(unsigned num_lits, literal * lits) {
void theory_str::assert_axiom(ast * a) {
/*
if (search_started) {
// effectively Z3_theory_assert_axiom
NOT_IMPLEMENTED_YET();
} else {
// effectively Z3_assert_cnstr
context & ctx = get_context();
ctx.assert_expr(to_expr(a));
}
*/
TRACE("t_str_detail", tout << "asserting " << mk_ismt2_pp(a, get_manager()) << "\n";);
expr * e = to_expr(a);
context & ctx = get_context();
TRACE("t_str_detail",
tout << "assert_axiom: literals:\n";
for (unsigned i = 0; i < num_lits; ++i) {
expr * e = ctx.bool_var2expr(lits[i].var());
if (lits[i].sign())
tout << "not ";
tout << mk_pp(e, get_manager()) << " ";
tout << "\n";
});
ctx.mk_th_axiom(get_id(), num_lits, lits);
}
void theory_str::assert_axiom(literal l) {
assert_axiom(1, &l);
ctx.internalize(e, false);
literal lit(ctx.get_literal(e));
ctx.mark_as_relevant(lit);
ctx.mk_th_axiom(get_id(), 1, &lit);
TRACE("t_str_detail", tout << "done asserting " << mk_ismt2_pp(a, get_manager()) << "\n";);
}
bool theory_str::internalize_atom(app * atom, bool gate_ctx) {
@ -93,15 +96,17 @@ bool theory_str::internalize_term(app * term) {
attach_new_th_var(e);
/*
if (is_concat(term)) {
instantiate_concat_axiom(e);
}
*/
return true;
}
app * theory_str::mk_strlen(app * e) {
if (m_strutil.is_string(e)) {
/*if (m_strutil.is_string(e)) {*/ if (false) {
const char * strval = 0;
m_strutil.is_string(e, &strval);
int len = strlen(strval);
@ -145,22 +150,90 @@ void theory_str::instantiate_concat_axiom(enode * cat) {
SASSERT(len_y);
// now build len_x + len_y
app * len_x_plus_len_y = m_autil.mk_add(len_x, len_y);
expr_ref len_x_plus_len_y(m);
len_x_plus_len_y = m_autil.mk_add(len_x, len_y);
SASSERT(len_x_plus_len_y);
TRACE("t_str", tout << mk_bounded_pp(len_xy, m) << " = " << mk_bounded_pp(len_x_plus_len_y, m) << "\n";);
// finally assert equality between the two subexpressions
literal l(mk_eq(len_xy, len_x_plus_len_y, true));
ctx.mark_as_relevant(l);
assert_axiom(l);
app * eq = m.mk_eq(len_xy, len_x_plus_len_y);
SASSERT(eq);
TRACE("t_str", tout << mk_bounded_pp(eq, m) << std::endl;);
assert_axiom(eq);
}
/*
* Add axioms that are true for any string variable:
* 1. Length(x) >= 0
* 2. Length(x) == 0 <=> x == ""
*/
void theory_str::instantiate_basic_string_axioms(enode * str) {
// generate a stronger axiom for constant strings
if (m_strutil.is_string(str->get_owner())) {
// TODO
} else {
// TODO keep track of which enodes we have added axioms for, so we don't add the same ones twice?
app * a_str = str->get_owner();
context & ctx = get_context();
ast_manager & m = get_manager();
// TODO find out why these are crashing the SMT solver
// build axiom 1: Length(a_str) >= 0
{
// build LHS
expr_ref len_str(m);
len_str = mk_strlen(a_str);
SASSERT(len_str);
// build RHS
expr_ref zero(m);
zero = m_autil.mk_numeral(rational(0), true);
SASSERT(zero);
// build LHS >= RHS and assert
app * lhs_ge_rhs = m_autil.mk_ge(len_str, zero);
SASSERT(lhs_ge_rhs);
// TODO verify that this works
TRACE("t_str_detail", tout << "string axiom 1: " << mk_bounded_pp(lhs_ge_rhs, m) << std::endl;);
assert_axiom(lhs_ge_rhs);
}
/*
// build axiom 2: Length(a_str) == 0 <=> a_str == ""
{
// build LHS of iff
expr_ref len_str(m);
len_str = mk_strlen(a_str);
SASSERT(len_str);
expr_ref zero(m);
zero = m_autil.mk_numeral(rational(0), true);
SASSERT(zero);
expr_ref lhs(m);
lhs = ctx.mk_eq_atom(len_str, zero);
SASSERT(lhs);
// build RHS of iff
expr_ref empty_str(m);
empty_str = m_strutil.mk_string("");
SASSERT(empty_str);
expr_ref rhs(m);
rhs = ctx.mk_eq_atom(a_str, empty_str);
SASSERT(rhs);
// build LHS <=> RHS and assert
TRACE("t_str_detail", tout << "string axiom 2: " << mk_bounded_pp(lhs, m) << " <=> " << mk_bounded_pp(rhs, m) << std::endl;);
// TODO this is kind of a hack, maybe just ctx.assert_expr() will be enough?
literal l(mk_eq(lhs, rhs, true));
ctx.mark_as_relevant(l);
assert_axiom(l);
}
*/
}
}
void theory_str::attach_new_th_var(enode * n) {
context & ctx = get_context();
theory_var v = mk_var(n);
ctx.attach_th_var(n, this, v);
TRACE("t_str_detail", tout << "new theory var: " << mk_ismt2_pp(n->get_owner(), get_manager()) << " := " << v << "\n";);
TRACE("t_str_detail", tout << "new theory var: " << mk_ismt2_pp(n->get_owner(), get_manager()) << " := v#" << v << std::endl;);
// probably okay...note however that this seems to miss constants and functions
//instantiate_basic_string_axioms(n);
}
void theory_str::init_search_eh() {
@ -180,14 +253,14 @@ void theory_str::init_search_eh() {
void theory_str::new_eq_eh(theory_var x, theory_var y) {
// TODO
TRACE("t_str", tout << "new eq: " << x << " = " << y << std::endl;);
TRACE("t_str", tout << "new eq: v#" << x << " = v#" << y << std::endl;);
TRACE("t_str_detail", tout << mk_ismt2_pp(get_enode(x)->get_owner(), get_manager()) << " = " <<
mk_ismt2_pp(get_enode(y)->get_owner(), get_manager()) << std::endl;);
}
void theory_str::new_diseq_eh(theory_var x, theory_var y) {
// TODO
TRACE("t_str", tout << "new diseq: " << x << " != " << y << std::endl;);
TRACE("t_str", tout << "new diseq: v#" << x << " != v#" << y << std::endl;);
TRACE("t_str_detail", tout << mk_ismt2_pp(get_enode(x)->get_owner(), get_manager()) << " != " <<
mk_ismt2_pp(get_enode(y)->get_owner(), get_manager()) << std::endl;);
}
@ -198,7 +271,7 @@ void theory_str::relevant_eh(app * n) {
void theory_str::assign_eh(bool_var v, bool is_true) {
context & ctx = get_context();
TRACE("t_str", tout << "assert: v" << v << " #" << ctx.bool_var2expr(v)->get_id() << " is_true: " << is_true << "\n";);
TRACE("t_str", tout << "assert: v" << v << " #" << ctx.bool_var2expr(v)->get_id() << " is_true: " << is_true << std::endl;);
}
void theory_str::push_scope_eh() {

View file

@ -36,6 +36,18 @@ namespace smt {
bool search_started;
arith_util m_autil;
str_util m_strutil;
protected:
void assert_axiom(ast * e);
app * mk_strlen(app * e);
bool is_concat(app const * a) const { return a->is_app_of(get_id(), OP_STRCAT); }
bool is_concat(enode const * n) const { return is_concat(n->get_owner()); }
void instantiate_concat_axiom(enode * cat);
void instantiate_basic_string_axioms(enode * str);
public:
theory_str(ast_manager & m);
virtual ~theory_str();
protected:
virtual bool internalize_atom(app * atom, bool gate_ctx);
virtual bool internalize_term(app * term);
@ -51,19 +63,6 @@ namespace smt {
virtual void push_scope_eh();
virtual final_check_status final_check_eh();
void assert_axiom(unsigned num_lits, literal * lits);
void assert_axiom(literal l);
app * mk_strlen(app * e);
bool is_concat(app const * a) const { return a->is_app_of(get_id(), OP_STRCAT); }
bool is_concat(enode const * n) const { return is_concat(n->get_owner()); }
void instantiate_concat_axiom(enode * cat);
public:
theory_str(ast_manager & m);
virtual ~theory_str();
protected:
void attach_new_th_var(enode * n);
};