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z3/src/smt/theory_user_propagator.cpp
Nikolaj Bjorner 9f78a96c1d wip - trim
2022-10-06 18:19:03 +02:00

427 lines
13 KiB
C++

/*++
Copyright (c) 2020 Microsoft Corporation
Module Name:
theory_user_propagator.cpp
Abstract:
User theory propagator plugin.
Author:
Nikolaj Bjorner (nbjorner) 2020-08-17
--*/
#include "ast/ast_pp.h"
#include "smt/theory_bv.h"
#include "smt/theory_user_propagator.h"
#include "smt/smt_context.h"
#include "ast/ast_ll_pp.h"
using namespace smt;
theory_user_propagator::theory_user_propagator(context& ctx):
theory(ctx, ctx.get_manager().mk_family_id(user_propagator::plugin::name())),
m_var2expr(ctx.get_manager()),
m_push_popping(false),
m_to_add(ctx.get_manager())
{}
theory_user_propagator::~theory_user_propagator() {
dealloc(m_api_context);
}
void theory_user_propagator::force_push() {
for (; m_num_scopes > 0; --m_num_scopes) {
flet<bool> _pushing(m_push_popping, true);
theory::push_scope_eh();
m_prop_lim.push_back(m_prop.size());
m_to_add_lim.push_back(m_to_add.size());
m_push_eh(m_user_context, this);
}
}
void theory_user_propagator::add_expr(expr* term, bool ensure_enode) {
force_push();
expr_ref r(m);
expr* e = term;
ctx.get_rewriter()(e, r);
TRACE("user_propagate", tout << "add " << mk_bounded_pp(e, m) << "\n");
if (r != e) {
r = m.mk_fresh_const("aux-expr", e->get_sort());
expr_ref eq(m.mk_eq(r, e), m);
ctx.assert_expr(eq);
ctx.internalize_assertions();
e = r;
ctx.mark_as_relevant(eq.get());
}
enode* n = ensure_enode ? this->ensure_enode(e) : ctx.get_enode(e);
if (is_attached_to_var(n))
return;
theory_var v = mk_var(n);
m_var2expr.reserve(v + 1);
m_var2expr[v] = term;
m_expr2var.setx(term->get_id(), v, null_theory_var);
if (m.is_bool(e) && !ctx.b_internalized(e)) {
bool_var bv = ctx.mk_bool_var(e);
ctx.set_var_theory(bv, get_id());
ctx.set_enode_flag(bv, true);
}
SASSERT(!m.is_bool(e) || ctx.b_internalized(e));
ctx.attach_th_var(n, this, v);
literal_vector explain;
if (ctx.is_fixed(n, r, explain))
m_prop.push_back(prop_info(explain, v, r));
}
void theory_user_propagator::propagate_cb(
unsigned num_fixed, expr* const* fixed_ids,
unsigned num_eqs, expr* const* eq_lhs, expr* const* eq_rhs,
expr* conseq) {
CTRACE("user_propagate", ctx.lit_internalized(conseq) && ctx.get_assignment(ctx.get_literal(conseq)) == l_true,
ctx.display(tout << "redundant consequence: " << mk_pp(conseq, m) << "\n"));
expr_ref _conseq(conseq, m);
ctx.get_rewriter()(conseq, _conseq);
if (ctx.lit_internalized(_conseq) && ctx.get_assignment(ctx.get_literal(_conseq)) == l_true)
return;
m_prop.push_back(prop_info(num_fixed, fixed_ids, num_eqs, eq_lhs, eq_rhs, _conseq));
}
void theory_user_propagator::register_cb(expr* e) {
if (m_push_popping)
m_to_add.push_back(e);
else
add_expr(e, true);
}
void theory_user_propagator::next_split_cb(expr* e, unsigned idx, lbool phase) {
if (e == nullptr) { // clear
m_next_split_expr = nullptr;
return;
}
ensure_enode(e);
m_next_split_expr = e;
m_next_split_idx = idx;
m_next_split_phase = phase;
}
theory * theory_user_propagator::mk_fresh(context * new_ctx) {
auto* th = alloc(theory_user_propagator, *new_ctx);
void* ctx;
try {
ctx = m_fresh_eh(m_user_context, new_ctx->get_manager(), th->m_api_context);
}
catch (...) {
throw default_exception("Exception thrown in \"fresh\"-callback");
}
th->add(ctx, m_push_eh, m_pop_eh, m_fresh_eh);
if ((bool)m_fixed_eh) th->register_fixed(m_fixed_eh);
if ((bool)m_final_eh) th->register_final(m_final_eh);
if ((bool)m_eq_eh) th->register_eq(m_eq_eh);
if ((bool)m_diseq_eh) th->register_diseq(m_diseq_eh);
if ((bool)m_created_eh) th->register_created(m_created_eh);
if ((bool)m_decide_eh) th->register_decide(m_decide_eh);
return th;
}
final_check_status theory_user_propagator::final_check_eh() {
if (!(bool)m_final_eh)
return FC_DONE;
force_push();
unsigned sz1 = m_prop.size();
unsigned sz2 = m_expr2var.size();
try {
m_final_eh(m_user_context, this);
}
catch (...) {
throw default_exception("Exception thrown in \"final\"-callback");
}
CTRACE("user_propagate", can_propagate(), tout << "can propagate\n");
propagate();
CTRACE("user_propagate", ctx.inconsistent(), tout << "inconsistent\n");
// check if it became inconsistent or something new was propagated/registered
bool done = (sz1 == m_prop.size()) && (sz2 == m_expr2var.size()) && !ctx.inconsistent();
return done ? FC_DONE : FC_CONTINUE;
}
void theory_user_propagator::new_fixed_eh(theory_var v, expr* value, unsigned num_lits, literal const* jlits) {
if (!m_fixed_eh)
return;
force_push();
if (m_fixed.contains(v))
return;
m_fixed.insert(v);
ctx.push_trail(insert_map<uint_set, unsigned>(m_fixed, v));
m_id2justification.setx(v, literal_vector(num_lits, jlits), literal_vector());
try {
m_fixed_eh(m_user_context, this, var2expr(v), value);
}
catch (...) {
throw default_exception("Exception thrown in \"fixed\"-callback");
}
}
bool_var theory_user_propagator::enode_to_bool(enode* n, unsigned bit) {
if (n->is_bool()) {
// expression is a boolean
bool_var new_var = ctx.enode2bool_var(n);
if (ctx.get_assignment(new_var) == l_undef)
return new_var;
return null_bool_var;
}
// expression is a bit-vector
bv_util bv(m);
auto th_bv = (theory_bv*)ctx.get_theory(bv.get_fid());
return th_bv->get_first_unassigned(bit, n);
}
void theory_user_propagator::decide(bool_var& var, bool& is_pos) {
if (!m_decide_eh)
return;
const bool_var_data& d = ctx.get_bdata(var);
if (!d.is_enode() && !d.is_theory_atom())
return;
enode* original_enode = nullptr;
unsigned original_bit = 0;
bv_util bv(m);
theory* th = nullptr;
theory_var v = null_theory_var;
// get the associated theory
if (!d.is_enode()) {
// it might be a value that does not have an enode
th = ctx.get_theory(d.get_theory());
}
else {
original_enode = ctx.bool_var2enode(var);
v = original_enode->get_th_var(get_family_id());
if (v == null_theory_var) {
// it is not a registered boolean expression
th = ctx.get_theory(d.get_theory());
}
}
if (v == null_theory_var && !th)
return;
if (v == null_theory_var && th->get_family_id() != bv.get_fid())
return;
if (v == null_theory_var) {
// it is not a registered boolean value but it is a bitvector
auto registered_bv = ((theory_bv*)th)->get_bv_with_theory(var, get_family_id());
if (!registered_bv.first)
// there is no registered bv associated with the bit
return;
original_enode = registered_bv.first;
original_bit = registered_bv.second;
v = original_enode->get_th_var(get_family_id());
}
// call the registered callback
unsigned new_bit = original_bit;
lbool phase = is_pos ? l_true : l_false;
expr* e = var2expr(v);
m_decide_eh(m_user_context, this, &e, &new_bit, &phase);
enode* new_enode = ctx.get_enode(e);
// check if the callback changed something
if (original_enode == new_enode && (new_enode->is_bool() || original_bit == new_bit)) {
if (phase != l_undef)
// it only affected the truth value
is_pos = phase == l_true;
return;
}
// get unassigned variable from enode
var = enode_to_bool(new_enode, new_bit);
if (var == null_bool_var)
// selected variable is already assigned
throw default_exception("expression in \"decide\" is already assigned");
// in case the callback did not decide on a truth value -> let Z3 decide
is_pos = ctx.guess(var, phase);
}
bool theory_user_propagator::get_case_split(bool_var& var, bool& is_pos){
if (!m_next_split_expr)
return false;
enode* n = ctx.get_enode(m_next_split_expr);
var = enode_to_bool(n, m_next_split_idx);
if (var == null_bool_var)
return false;
is_pos = ctx.guess(var, m_next_split_phase);
m_next_split_expr = nullptr;
return true;
}
void theory_user_propagator::push_scope_eh() {
++m_num_scopes;
}
void theory_user_propagator::pop_scope_eh(unsigned num_scopes) {
flet<bool> _popping(m_push_popping, true);
unsigned n = std::min(num_scopes, m_num_scopes);
m_num_scopes -= n;
num_scopes -= n;
if (num_scopes == 0)
return;
theory::pop_scope_eh(num_scopes);
unsigned old_sz = m_prop_lim.size() - num_scopes;
m_prop.shrink(m_prop_lim[old_sz]);
m_prop_lim.shrink(old_sz);
old_sz = m_to_add_lim.size() - num_scopes;
m_to_add.shrink(m_to_add_lim[old_sz]);
m_to_add_lim.shrink(old_sz);
m_pop_eh(m_user_context, this, num_scopes);
}
bool theory_user_propagator::can_propagate() {
return m_qhead < m_prop.size() || m_to_add_qhead < m_to_add.size();
}
void theory_user_propagator::propagate_consequence(prop_info const& prop) {
justification* js;
m_lits.reset();
m_eqs.reset();
for (expr* id : prop.m_ids)
m_lits.append(m_id2justification[expr2var(id)]);
for (auto const& [a,b] : prop.m_eqs)
if (a != b)
m_eqs.push_back(enode_pair(get_enode(expr2var(a)), get_enode(expr2var(b))));
DEBUG_CODE(for (auto const& [a, b] : m_eqs) VERIFY(a->get_root() == b->get_root()););
DEBUG_CODE(for (expr* e : prop.m_ids) VERIFY(m_fixed.contains(expr2var(e))););
DEBUG_CODE(for (literal lit : m_lits) VERIFY(ctx.get_assignment(lit) == l_true););
TRACE("user_propagate", tout << "propagating #" << prop.m_conseq->get_id() << ": " << prop.m_conseq << "\n";
for (auto const& [a,b] : m_eqs) tout << enode_pp(a, ctx) << " == " << enode_pp(b, ctx) << "\n";
for (expr* e : prop.m_ids) tout << mk_pp(e, m) << "\n";
for (literal lit : m_lits) tout << lit << "\n");
if (m.is_false(prop.m_conseq)) {
js = ctx.mk_justification(
ext_theory_conflict_justification(
get_id(), ctx, m_lits.size(), m_lits.data(), m_eqs.size(), m_eqs.data(), 0, nullptr));
ctx.set_conflict(js);
}
else {
#if 1
for (auto& lit : m_lits)
lit.neg();
for (auto const& [a,b] : m_eqs)
m_lits.push_back(~mk_eq(a->get_expr(), b->get_expr(), false));
#endif
literal lit;
if (has_quantifiers(prop.m_conseq)) {
expr_ref fn(m.mk_fresh_const("aux-literal", m.mk_bool_sort()), m);
expr_ref eq(m.mk_eq(fn, prop.m_conseq), m);
ctx.assert_expr(eq);
ctx.internalize_assertions();
lit = mk_literal(fn);
}
else
lit = mk_literal(prop.m_conseq);
ctx.mark_as_relevant(lit);
#if 0
justification* js =
ctx.mk_justification(
ext_theory_propagation_justification(
get_id(), ctx, m_lits.size(), m_lits.data(), m_eqs.size(), m_eqs.data(), lit));
ctx.assign(lit, js);
#endif
#if 1
m_lits.push_back(lit);
ctx.mk_th_lemma(get_id(), m_lits);
#endif
TRACE("user_propagate", ctx.display(tout););
}
}
void theory_user_propagator::propagate_new_fixed(prop_info const& prop) {
new_fixed_eh(prop.m_var, prop.m_conseq, prop.m_lits.size(), prop.m_lits.data());
}
void theory_user_propagator::propagate() {
if (m_qhead == m_prop.size() && m_to_add_qhead == m_to_add.size())
return;
TRACE("user_propagate", tout << "propagating queue head: " << m_qhead << " prop queue: " << m_prop.size() << "\n");
force_push();
unsigned qhead = m_to_add_qhead;
if (qhead < m_to_add.size()) {
for (; qhead < m_to_add.size(); ++qhead)
add_expr(m_to_add.get(qhead), true);
ctx.push_trail(value_trail<unsigned>(m_to_add_qhead));
m_to_add_qhead = qhead;
}
qhead = m_qhead;
while (qhead < m_prop.size() && !ctx.inconsistent()) {
auto const& prop = m_prop[qhead];
if (prop.m_var == null_theory_var)
propagate_consequence(prop);
else
propagate_new_fixed(prop);
++m_stats.m_num_propagations;
++qhead;
}
ctx.push_trail(value_trail<unsigned>(m_qhead));
m_qhead = qhead;
}
bool theory_user_propagator::internalize_atom(app* atom, bool gate_ctx) {
return internalize_term(atom);
}
bool theory_user_propagator::internalize_term(app* term) {
for (auto arg : *term)
ensure_enode(arg);
if (term->get_family_id() == get_id() && !ctx.e_internalized(term))
ctx.mk_enode(term, true, false, true);
add_expr(term, false);
if (!m_created_eh)
throw default_exception("You have to register a created event handler for new terms if you track them");
try {
m_created_eh(m_user_context, this, term);
}
catch (...) {
throw default_exception("Exception thrown in \"created\"-callback");
}
return true;
}
void theory_user_propagator::collect_statistics(::statistics & st) const {
st.update("user-propagations", m_stats.m_num_propagations);
st.update("user-watched", get_num_vars());
}