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z3/src/smt/nseq_state.h

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3.5 KiB
C++

/*++
Copyright (c) 2026 Microsoft Corporation
Module Name:
nseq_state.h
Abstract:
Constraint store bridging the SMT context to the Nielsen graph.
Holds word equations and regex membership constraints with
push/pop support for backtracking.
Author:
Nikolaj Bjorner (nbjorner) 2026-03-01
--*/
#pragma once
#include "util/vector.h"
#include "ast/euf/euf_sgraph.h"
#include "smt/seq/seq_nielsen.h"
#include "smt/smt_literal.h"
namespace smt {
class enode;
// source info for a string equality (the two enodes whose merge caused it)
struct eq_source {
enode* m_n1;
enode* m_n2;
};
// source info for a regex membership (the literal that asserted it)
struct mem_source {
literal m_lit;
};
// source info for a string disequality
struct diseq_source {
enode* m_n1;
enode* m_n2;
};
class nseq_state {
euf::sgraph& m_sg;
vector<seq::str_eq> m_str_eqs;
vector<seq::str_mem> m_str_mems;
vector<eq_source> m_eq_sources;
vector<mem_source> m_mem_sources;
vector<diseq_source> m_diseqs;
unsigned_vector m_str_eq_lim;
unsigned_vector m_str_mem_lim;
unsigned_vector m_diseq_lim;
unsigned m_next_mem_id = 0;
public:
nseq_state(euf::sgraph& sg) : m_sg(sg) {}
void push() {
m_str_eq_lim.push_back(m_str_eqs.size());
m_str_mem_lim.push_back(m_str_mems.size());
m_diseq_lim.push_back(m_diseqs.size());
}
void pop(unsigned n) {
for (unsigned i = 0; i < n; ++i) {
m_str_eqs.shrink(m_str_eq_lim.back());
m_eq_sources.shrink(m_str_eq_lim.back());
m_str_eq_lim.pop_back();
m_str_mems.shrink(m_str_mem_lim.back());
m_mem_sources.shrink(m_str_mem_lim.back());
m_str_mem_lim.pop_back();
m_diseqs.shrink(m_diseq_lim.back());
m_diseq_lim.pop_back();
}
}
void add_str_eq(euf::snode* lhs, euf::snode* rhs, enode* n1, enode* n2) {
seq::dep_tracker dep;
m_str_eqs.push_back(seq::str_eq(lhs, rhs, dep));
m_eq_sources.push_back({n1, n2});
}
void add_str_mem(euf::snode* str, euf::snode* regex, literal lit) {
seq::dep_tracker dep;
m_str_mems.push_back(seq::str_mem(str, regex, nullptr, m_next_mem_id++, dep));
m_mem_sources.push_back({lit});
}
void add_diseq(enode* n1, enode* n2) {
m_diseqs.push_back({n1, n2});
}
vector<seq::str_eq> const& str_eqs() const { return m_str_eqs; }
vector<seq::str_mem> const& str_mems() const { return m_str_mems; }
vector<diseq_source> const& diseqs() const { return m_diseqs; }
eq_source const& get_eq_source(unsigned i) const { return m_eq_sources[i]; }
mem_source const& get_mem_source(unsigned i) const { return m_mem_sources[i]; }
diseq_source const& get_diseq(unsigned i) const { return m_diseqs[i]; }
bool empty() const { return m_str_eqs.empty() && m_str_mems.empty() && m_diseqs.empty(); }
void reset() {
m_str_eqs.reset();
m_str_mems.reset();
m_eq_sources.reset();
m_mem_sources.reset();
m_diseqs.reset();
m_str_eq_lim.reset();
m_str_mem_lim.reset();
m_diseq_lim.reset();
}
};
}