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LastIndexof support

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This commit is contained in:
Murphy Berzish 2016-06-15 18:45:01 -04:00
parent 7c8b882ae6
commit be5bf7fb80
2 changed files with 83 additions and 1 deletions
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80
src/smt/theory_str.cpp
View file

@ -611,7 +611,7 @@ expr * theory_str::mk_concat(expr * n1, expr * n2) {
bool theory_str::can_propagate() {
return !m_basicstr_axiom_todo.empty() || !m_str_eq_todo.empty() || !m_concat_axiom_todo.empty()
|| !m_axiom_CharAt_todo.empty() || !m_axiom_StartsWith_todo.empty() || !m_axiom_EndsWith_todo.empty()
|| !m_axiom_Contains_todo.empty() || !m_axiom_Indexof_todo.empty() || !m_axiom_Indexof2_todo.empty()
|| !m_axiom_Contains_todo.empty() || !m_axiom_Indexof_todo.empty() || !m_axiom_Indexof2_todo.empty() || !m_axiom_LastIndexof_todo.empty()
;
}
@ -665,6 +665,11 @@ void theory_str::propagate() {
instantiate_axiom_Indexof2(m_axiom_Indexof2_todo[i]);
}
m_axiom_Indexof2_todo.reset();
for (unsigned i = 0; i < m_axiom_LastIndexof_todo.size(); ++i) {
instantiate_axiom_LastIndexof(m_axiom_LastIndexof_todo[i]);
}
m_axiom_LastIndexof_todo.reset();
}
}
@ -1076,6 +1081,75 @@ void theory_str::instantiate_axiom_Indexof2(enode * e) {
assert_axiom(reduceTerm);
}
void theory_str::instantiate_axiom_LastIndexof(enode * e) {
context & ctx = get_context();
ast_manager & m = get_manager();
app * expr = e->get_owner();
if (axiomatized_terms.contains(expr)) {
TRACE("t_str_detail", tout << "already set up LastIndexof axiom for " << mk_pp(expr, m) << std::endl;);
return;
}
axiomatized_terms.insert(expr);
TRACE("t_str_detail", tout << "instantiate LastIndexof axiom for " << mk_pp(expr, m) << std::endl;);
expr_ref x1(mk_str_var("x1"), m);
expr_ref x2(mk_str_var("x2"), m);
expr_ref indexAst(mk_int_var("index"), m);
expr_ref_vector items(m);
// args[0] = x1 . args[1] . x2
expr_ref eq1(ctx.mk_eq_atom(expr->get_arg(0), mk_concat(x1, mk_concat(expr->get_arg(1), x2))), m);
expr_ref arg0HasArg1(mk_contains(expr->get_arg(0), expr->get_arg(1)), m); // arg0HasArg1 = Contains(args[0], args[1])
items.push_back(ctx.mk_eq_atom(arg0HasArg1, eq1));
expr_ref condAst(arg0HasArg1, m);
//----------------------------
// true branch
expr_ref_vector thenItems(m);
thenItems.push_back(m_autil.mk_ge(indexAst, mk_int(0)));
// args[0] = x1 . args[1] . x2
// x1 doesn't contain args[1]
thenItems.push_back(m.mk_not(mk_contains(x2, expr->get_arg(1))));
thenItems.push_back(ctx.mk_eq_atom(indexAst, mk_strlen(x1)));
bool canSkip = false;
if (m_strutil.is_string(expr->get_arg(1))) {
std::string arg1Str = m_strutil.get_string_constant_value(expr->get_arg(1));
if (arg1Str.length() == 1) {
canSkip = true;
}
}
if (!canSkip) {
// args[0] = x3 . x4 /\ |x3| = |x1| + 1 /\ ! contains(x4, args[1])
expr_ref x3(mk_str_var("x3"), m);
expr_ref x4(mk_str_var("x4"), m);
expr_ref tmpLen(m_autil.mk_add(indexAst, mk_int(1)), m);
thenItems.push_back(ctx.mk_eq_atom(expr->get_arg(0), mk_concat(x3, x4)));
thenItems.push_back(ctx.mk_eq_atom(mk_strlen(x3), tmpLen));
thenItems.push_back(m.mk_not(mk_contains(x4, expr->get_arg(1))));
}
//----------------------------
// else branch
expr_ref_vector elseItems(m);
elseItems.push_back(ctx.mk_eq_atom(indexAst, mk_int(-1)));
items.push_back(m.mk_ite(condAst, m.mk_and(thenItems.size(), thenItems.c_ptr()), m.mk_and(elseItems.size(), elseItems.c_ptr())));
expr_ref breakdownAssert(m.mk_and(items.size(), items.c_ptr()), m);
SASSERT(breakdownAssert);
expr_ref reduceToIndex(ctx.mk_eq_atom(expr, indexAst), m);
SASSERT(reduceToIndex);
expr_ref finalAxiom(m.mk_and(breakdownAssert, reduceToIndex), m);
SASSERT(finalAxiom);
assert_axiom(finalAxiom);
}
void theory_str::attach_new_th_var(enode * n) {
context & ctx = get_context();
theory_var v = mk_var(n);
@ -3850,6 +3924,10 @@ void theory_str::set_up_axioms(expr * ex) {
app * ap = to_app(ex);
if (is_Indexof(ap)) {
m_axiom_Indexof_todo.push_back(n);
} else if (is_Indexof2(ap)) {
m_axiom_Indexof2_todo.push_back(n);
} else if (is_LastIndexof(ap)) {
m_axiom_LastIndexof_todo.push_back(n);
}
}
} else {

4
src/smt/theory_str.h
View file

@ -114,6 +114,7 @@ namespace smt {
ptr_vector<enode> m_axiom_Contains_todo;
ptr_vector<enode> m_axiom_Indexof_todo;
ptr_vector<enode> m_axiom_Indexof2_todo;
ptr_vector<enode> m_axiom_LastIndexof_todo;
// hashtable of all exprs for which we've already set up term-specific axioms --
// this prevents infinite recursive descent with respect to axioms that
@ -196,6 +197,8 @@ namespace smt {
bool is_Indexof(enode const * n) const { return is_Indexof(n->get_owner()); }
bool is_Indexof2(app const * a) const { return a->is_app_of(get_id(), OP_STR_INDEXOF2); }
bool is_Indexof2(enode const * n) const { return is_Indexof2(n->get_owner()); }
bool is_LastIndexof(app const * a) const { return a->is_app_of(get_id(), OP_STR_LASTINDEXOF); }
bool is_LastIndexof(enode const * n) const { return is_LastIndexof(n->get_owner()); }
void instantiate_concat_axiom(enode * cat);
void instantiate_basic_string_axioms(enode * str);
@ -207,6 +210,7 @@ namespace smt {
void instantiate_axiom_Contains(enode * e);
void instantiate_axiom_Indexof(enode * e);
void instantiate_axiom_Indexof2(enode * e);
void instantiate_axiom_LastIndexof(enode * e);
void set_up_axioms(expr * ex);
void handle_equality(expr * lhs, expr * rhs);