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Add commands: (prefer <formula>) - will instruct case split queue to assign formula to true. - prefer commands added within a scope are forgotten after leaving the scope. (reset-preferences) - resets asserted preferences. Has to be invoked at base level. This provides functionality related to MathSAT and based on an ask by Tomáš Kolárik who is integrating the functionality with OpenSMT2
428 lines
14 KiB
C++
428 lines
14 KiB
C++
/*++
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Copyright (c) 2020 Microsoft Corporation
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Module Name:
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theory_user_propagator.cpp
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Abstract:
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User theory propagator plugin.
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Author:
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Nikolaj Bjorner (nbjorner) 2020-08-17
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--*/
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#include "ast/ast_pp.h"
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#include "smt/theory_bv.h"
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#include "smt/theory_user_propagator.h"
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#include "smt/smt_context.h"
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#include "ast/ast_ll_pp.h"
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using namespace smt;
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theory_user_propagator::theory_user_propagator(context& ctx):
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theory(ctx, ctx.get_manager().mk_family_id(user_propagator::plugin::name())),
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m_var2expr(ctx.get_manager()),
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m_push_popping(false),
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m_to_add(ctx.get_manager())
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{}
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theory_user_propagator::~theory_user_propagator() {
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dealloc(m_api_context);
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}
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void theory_user_propagator::force_push() {
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for (; m_num_scopes > 0; --m_num_scopes) {
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flet<bool> _pushing(m_push_popping, true);
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theory::push_scope_eh();
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m_prop_lim.push_back(m_prop.size());
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m_to_add_lim.push_back(m_to_add.size());
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m_push_eh(m_user_context, this);
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}
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}
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void theory_user_propagator::add_expr(expr* term, bool ensure_enode) {
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force_push();
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expr_ref r(m);
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expr* e = term;
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ctx.get_rewriter()(e, r);
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TRACE(user_propagate, tout << "add " << mk_bounded_pp(e, m) << "\n");
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if (!is_ground(r)) {
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if (m_add_expr_fresh.contains(term))
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return;
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m_add_expr_fresh.insert(term);
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ctx.push_trail(insert_obj_trail(m_add_expr_fresh, term));
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r = m.mk_fresh_const("aux-expr", e->get_sort());
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expr_ref eq(m.mk_eq(r, e), m);
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ctx.assert_expr(eq);
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ctx.internalize_assertions();
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ctx.mark_as_relevant(eq.get());
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}
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e = r;
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enode* n = ensure_enode ? this->ensure_enode(e) : ctx.get_enode(e);
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if (is_attached_to_var(n))
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return;
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theory_var v = mk_var(n);
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m_var2expr.reserve(v + 1);
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m_var2expr[v] = term;
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m_expr2var.setx(term->get_id(), v, null_theory_var);
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if (m.is_bool(e) && !ctx.b_internalized(e)) {
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bool_var bv = ctx.mk_bool_var(e);
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ctx.set_var_theory(bv, get_id());
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ctx.set_enode_flag(bv, true);
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}
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SASSERT(!m.is_bool(e) || ctx.b_internalized(e));
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ctx.attach_th_var(n, this, v);
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literal_vector explain;
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if (ctx.is_fixed(n, r, explain))
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m_prop.push_back(prop_info(explain, v, r));
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}
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bool theory_user_propagator::propagate_cb(
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unsigned num_fixed, expr* const* fixed_ids,
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unsigned num_eqs, expr* const* eq_lhs, expr* const* eq_rhs,
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expr* conseq) {
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CTRACE(user_propagate, ctx.lit_internalized(conseq) && ctx.get_assignment(ctx.get_literal(conseq)) == l_true,
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ctx.display(tout << "redundant consequence: " << mk_pp(conseq, m) << "\n"));
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expr_ref _conseq(conseq, m);
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ctx.get_rewriter()(conseq, _conseq);
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if (!ctx.get_manager().is_true(_conseq) && !ctx.get_manager().is_false(_conseq))
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ctx.mark_as_relevant((expr*)_conseq);
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if (ctx.lit_internalized(_conseq) && ctx.get_assignment(ctx.get_literal(_conseq)) == l_true)
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return false;
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m_prop.push_back(prop_info(num_fixed, fixed_ids, num_eqs, eq_lhs, eq_rhs, _conseq));
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return true;
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}
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void theory_user_propagator::register_cb(expr* e) {
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if (m_push_popping)
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m_to_add.push_back(e);
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else
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add_expr(e, true);
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}
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void theory_user_propagator::register_on_binding(user_propagator::binding_eh_t& binding_eh) {
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std::function<bool(quantifier* q, expr* inst)> on_binding =
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[this, binding_eh](quantifier* q, expr* inst) {
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return binding_eh(m_user_context, this, q, inst);
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};
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ctx.register_on_binding(on_binding);
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}
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bool theory_user_propagator::next_split_cb(expr* e, unsigned idx, lbool phase) {
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if (e == nullptr) { // clear
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m_next_split_var = nullptr;
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return true;
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}
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if (!ctx.e_internalized(e)) {
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// We may not eagerly internalize it (might crash when done in pop) => delay
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m_next_split_var = e;
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return true;
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}
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bool_var b = enode_to_bool(ctx.get_enode(e), idx);
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if (b == null_bool_var || ctx.get_assignment(b) != l_undef)
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return false;
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m_next_split_var = e;
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m_next_split_idx = idx;
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m_next_split_phase = phase;
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return true;
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}
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theory * theory_user_propagator::mk_fresh(context * new_ctx) {
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auto* th = alloc(theory_user_propagator, *new_ctx);
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void* ctx;
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try {
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ctx = m_fresh_eh(m_user_context, new_ctx->get_manager(), th->m_api_context);
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}
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catch (...) {
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throw default_exception("Exception thrown in \"fresh\"-callback");
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}
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th->add(ctx, m_push_eh, m_pop_eh, m_fresh_eh);
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if ((bool)m_fixed_eh) th->register_fixed(m_fixed_eh);
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if ((bool)m_final_eh) th->register_final(m_final_eh);
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if ((bool)m_eq_eh) th->register_eq(m_eq_eh);
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if ((bool)m_diseq_eh) th->register_diseq(m_diseq_eh);
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if ((bool)m_created_eh) th->register_created(m_created_eh);
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if ((bool)m_decide_eh) th->register_decide(m_decide_eh);
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return th;
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}
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final_check_status theory_user_propagator::final_check_eh() {
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if (!(bool)m_final_eh)
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return FC_DONE;
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force_push();
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unsigned sz1 = m_prop.size();
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unsigned sz2 = get_num_vars();
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try {
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m_final_eh(m_user_context, this);
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}
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catch (...) {
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throw default_exception("Exception thrown in \"final\"-callback");
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}
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CTRACE(user_propagate, can_propagate(), tout << "can propagate\n");
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propagate();
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CTRACE(user_propagate, ctx.inconsistent(), tout << "inconsistent\n");
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// check if it became inconsistent or something new was propagated/registered
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bool done = (sz1 == m_prop.size()) && (sz2 == get_num_vars()) && !ctx.inconsistent();
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return done ? FC_DONE : FC_CONTINUE;
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}
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void theory_user_propagator::new_fixed_eh(theory_var v, expr* value, unsigned num_lits, literal const* jlits) {
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if (!m_fixed_eh)
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return;
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force_push();
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if (m_fixed.contains(v))
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return;
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m_fixed.insert(v);
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ctx.push_trail(insert_map<uint_set, unsigned>(m_fixed, v));
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m_id2justification.setx(v, literal_vector(num_lits, jlits), literal_vector());
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try {
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m_fixed_eh(m_user_context, this, var2expr(v), value);
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}
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catch (...) {
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throw default_exception("Exception thrown in \"fixed\"-callback");
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}
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}
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bool_var theory_user_propagator::enode_to_bool(enode* n, unsigned idx) {
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if (n->is_bool()) {
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// expression is a boolean
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return ctx.enode2bool_var(n);
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}
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// expression is a bit-vector
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bv_util bv(m);
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auto th_bv = (theory_bv*)ctx.get_theory(bv.get_fid());
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return th_bv->get_bit(idx, n);
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}
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void theory_user_propagator::decide(bool_var& var, bool& is_pos) {
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if (!m_decide_eh)
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return;
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expr *e = ctx.bool_var2expr(var);
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if (!e)
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e = m.mk_true(); // use a dummy case split atom.
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unsigned bit = 0;
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// determine if case split is a bit-position in a bit-vector
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{
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bv_util bv(m);
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auto th = ctx.get_theory(bv.get_fid());
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if (th) {
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// it is then n'th bit of a bit-vector n.
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auto [n, nbit] = static_cast<theory_bv *>(th)->get_bv_with_theory(var, get_family_id());
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if (n) {
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e = n->get_expr();
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bit = nbit;
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}
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}
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}
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force_push();
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m_decide_eh(m_user_context, this, e, bit, is_pos);
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bool_var new_var;
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if (!get_case_split(new_var, is_pos) || new_var == var)
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// The user did not interfere
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return;
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TRACE(user_propagate,
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tout << "decide: " << ctx.bool_var2expr(var) << " -> " << ctx.bool_var2expr(new_var) << "\n");
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var = new_var;
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// check if the new variable is unassigned
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if (ctx.get_assignment(var) != l_undef)
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throw default_exception("expression in \"decide\" is already assigned");
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}
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bool theory_user_propagator::get_case_split(bool_var& var, bool& is_pos) {
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if (m_next_split_var == nullptr)
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return false;
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ensure_enode(m_next_split_var);
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bool_var b = enode_to_bool(ctx.get_enode(m_next_split_var), m_next_split_idx);
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if (b == null_bool_var || ctx.get_assignment(b) != l_undef)
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return false;
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var = b;
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is_pos = ctx.guess(var, m_next_split_phase);
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m_next_split_var = nullptr;
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m_next_split_idx = 0;
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m_next_split_phase = l_undef;
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return true;
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}
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void theory_user_propagator::push_scope_eh() {
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++m_num_scopes;
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}
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void theory_user_propagator::pop_scope_eh(unsigned num_scopes) {
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flet<bool> _popping(m_push_popping, true);
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unsigned n = std::min(num_scopes, m_num_scopes);
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m_num_scopes -= n;
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num_scopes -= n;
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if (num_scopes == 0)
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return;
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theory::pop_scope_eh(num_scopes);
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unsigned old_sz = m_prop_lim.size() - num_scopes;
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m_prop.shrink(m_prop_lim[old_sz]);
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m_prop_lim.shrink(old_sz);
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old_sz = m_to_add_lim.size() - num_scopes;
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m_to_add.shrink(m_to_add_lim[old_sz]);
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m_to_add_lim.shrink(old_sz);
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m_pop_eh(m_user_context, this, num_scopes);
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}
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bool theory_user_propagator::can_propagate() {
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return m_qhead < m_prop.size() || m_to_add_qhead < m_to_add.size() || m_replay_qhead < m_clauses_to_replay.size();
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}
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void theory_user_propagator::propagate_consequence(prop_info const& prop) {
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justification* js;
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m_lits.reset();
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m_eqs.reset();
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for (expr* id: prop.m_ids)
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m_lits.append(m_id2justification[expr2var(id)]);
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for (auto const& [a, b]: prop.m_eqs)
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if (a != b)
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m_eqs.push_back(enode_pair(get_enode(expr2var(a)), get_enode(expr2var(b))));
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DEBUG_CODE(for (auto const& [a, b] : m_eqs) VERIFY(a->get_root() == b->get_root()););
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DEBUG_CODE(for (expr* e : prop.m_ids) VERIFY(m_fixed.contains(expr2var(e))););
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DEBUG_CODE(for (literal lit : m_lits) VERIFY(ctx.get_assignment(lit) == l_true););
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TRACE(user_propagate, tout << "propagating #" << prop.m_conseq->get_id() << ": " << prop.m_conseq << "\n";
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for (auto const& [a,b] : m_eqs) tout << enode_pp(a, ctx) << " == " << enode_pp(b, ctx) << "\n";
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for (expr* e : prop.m_ids) tout << mk_pp(e, m) << "\n";
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for (literal lit : m_lits) tout << lit << "\n");
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if (m.is_false(prop.m_conseq)) {
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js = ctx.mk_justification(
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ext_theory_conflict_justification(
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get_id(), ctx, m_lits.size(), m_lits.data(), m_eqs.size(), m_eqs.data(), 0, nullptr));
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ctx.set_conflict(js);
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}
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else {
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for (auto& lit : m_lits)
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lit.neg();
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for (auto const& [a,b] : m_eqs)
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m_lits.push_back(~mk_eq(a->get_expr(), b->get_expr(), false));
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literal lit;
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if (has_quantifiers(prop.m_conseq)) {
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expr_ref fn(m.mk_fresh_const("aux-literal", m.mk_bool_sort()), m);
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expr_ref eq(m.mk_eq(fn, prop.m_conseq), m);
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ctx.assert_expr(eq);
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ctx.internalize_assertions();
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lit = mk_literal(fn);
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}
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else
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lit = mk_literal(prop.m_conseq);
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ctx.mark_as_relevant(lit);
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m_lits.push_back(lit);
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if (ctx.get_fparams().m_up_persist_clauses) {
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expr_ref_vector clause(m);
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for (auto l : m_lits)
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clause.push_back(ctx.literal2expr(l));
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m_clauses_to_replay.push_back(clause);
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if (m_replay_qhead + 1 < m_clauses_to_replay.size())
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std::swap(m_clauses_to_replay[m_replay_qhead], m_clauses_to_replay[m_clauses_to_replay.size()-1]);
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ctx.push_trail(value_trail<unsigned>(m_replay_qhead));
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++m_replay_qhead;
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ctx.mk_th_axiom(get_id(), m_lits);
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}
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else
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ctx.mk_th_lemma(get_id(), m_lits);
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}
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TRACE(user_propagate, ctx.display(tout););
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}
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void theory_user_propagator::propagate_new_fixed(prop_info const& prop) {
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new_fixed_eh(prop.m_var, prop.m_conseq, prop.m_lits.size(), prop.m_lits.data());
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}
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void theory_user_propagator::propagate() {
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if (m_qhead == m_prop.size() && m_to_add_qhead == m_to_add.size() && m_replay_qhead == m_clauses_to_replay.size())
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return;
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TRACE(user_propagate, tout << "propagating queue head: " << m_qhead << " prop queue: " << m_prop.size() << "\n");
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force_push();
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unsigned qhead = m_replay_qhead;
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if (qhead < m_clauses_to_replay.size()) {
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for (; qhead < m_clauses_to_replay.size() && !ctx.inconsistent(); ++qhead)
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replay_clause(m_clauses_to_replay.get(qhead));
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ctx.push_trail(value_trail<unsigned>(m_replay_qhead));
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m_replay_qhead = qhead;
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}
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qhead = m_to_add_qhead;
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if (qhead < m_to_add.size()) {
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for (; qhead < m_to_add.size(); ++qhead)
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add_expr(m_to_add.get(qhead), true);
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ctx.push_trail(value_trail<unsigned>(m_to_add_qhead));
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m_to_add_qhead = qhead;
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}
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qhead = m_qhead;
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while (qhead < m_prop.size() && !ctx.inconsistent()) {
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auto const& prop = m_prop[qhead];
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if (prop.m_var == null_theory_var)
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propagate_consequence(prop);
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else
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propagate_new_fixed(prop);
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++m_stats.m_num_propagations;
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++qhead;
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}
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ctx.push_trail(value_trail<unsigned>(m_qhead));
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m_qhead = qhead;
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}
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void theory_user_propagator::replay_clause(expr_ref_vector const& clause) {
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m_lits.reset();
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for (expr* e : clause)
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m_lits.push_back(mk_literal(e));
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ctx.mk_th_axiom(get_id(), m_lits);
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}
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bool theory_user_propagator::internalize_atom(app* atom, bool gate_ctx) {
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return internalize_term(atom);
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}
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bool theory_user_propagator::internalize_term(app* term) {
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for (auto arg : *term)
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ensure_enode(arg);
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if (term->get_family_id() == get_id() && !ctx.e_internalized(term))
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ctx.mk_enode(term, true, false, true);
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add_expr(term, false);
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if (!m_created_eh)
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throw default_exception("You have to register a created event handler for new terms if you track them");
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try {
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m_created_eh(m_user_context, this, term);
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}
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catch (...) {
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throw default_exception("Exception thrown in \"created\"-callback");
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}
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return true;
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}
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void theory_user_propagator::collect_statistics(::statistics& st) const {
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st.update("user-propagations", m_stats.m_num_propagations);
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st.update("user-watched", get_num_vars());
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}
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