3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-10 19:27:06 +00:00
z3/src/smt/theory_seq.h
Nikolaj Bjorner aec5a38b14 fix memory leak in SAT solver exposed by regression tests
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2016-01-06 11:44:55 -08:00

511 lines
21 KiB
C++

/*++
Copyright (c) 2011 Microsoft Corporation
Module Name:
theory_seq.h
Abstract:
Native theory solver for sequences.
Author:
Nikolaj Bjorner (nbjorner) 2015-6-12
Revision History:
--*/
#ifndef THEORY_SEQ_H_
#define THEORY_SEQ_H_
#include "smt_theory.h"
#include "seq_decl_plugin.h"
#include "theory_seq_empty.h"
#include "th_rewriter.h"
#include "ast_trail.h"
#include "scoped_vector.h"
#include "scoped_ptr_vector.h"
#include "automaton.h"
#include "seq_rewriter.h"
namespace smt {
class theory_seq : public theory {
struct assumption {
enode* n1, *n2;
literal lit;
assumption(enode* n1, enode* n2): n1(n1), n2(n2), lit(null_literal) {}
assumption(literal lit): n1(0), n2(0), lit(lit) {}
};
typedef scoped_dependency_manager<assumption> dependency_manager;
typedef dependency_manager::dependency dependency;
typedef trail_stack<theory_seq> th_trail_stack;
typedef std::pair<expr*, dependency*> expr_dep;
typedef obj_map<expr, expr_dep> eqdep_map_t;
// cache to track evaluations under equalities
class eval_cache {
eqdep_map_t m_map;
expr_ref_vector m_trail;
public:
eval_cache(ast_manager& m): m_trail(m) {}
bool find(expr* v, expr_dep& r) const { return m_map.find(v, r); }
void insert(expr* v, expr_dep& r) { m_trail.push_back(v); m_trail.push_back(r.first); m_map.insert(v, r); }
void reset() { m_map.reset(); m_trail.reset(); }
};
// map from variables to representatives
// + a cache for normalization.
class solution_map {
enum map_update { INS, DEL };
ast_manager& m;
dependency_manager& m_dm;
eqdep_map_t m_map;
eval_cache m_cache;
expr_ref_vector m_lhs, m_rhs;
ptr_vector<dependency> m_deps;
svector<map_update> m_updates;
unsigned_vector m_limit;
void add_trail(map_update op, expr* l, expr* r, dependency* d);
public:
solution_map(ast_manager& m, dependency_manager& dm):
m(m), m_dm(dm), m_cache(m), m_lhs(m), m_rhs(m) {}
bool empty() const { return m_map.empty(); }
void update(expr* e, expr* r, dependency* d);
void add_cache(expr* v, expr_dep& r) { m_cache.insert(v, r); }
bool find_cache(expr* v, expr_dep& r) { return m_cache.find(v, r); }
expr* find(expr* e, dependency*& d);
expr* find(expr* e);
bool is_root(expr* e) const;
void cache(expr* e, expr* r, dependency* d);
void reset_cache() { m_cache.reset(); }
void push_scope() { m_limit.push_back(m_updates.size()); }
void pop_scope(unsigned num_scopes);
void display(std::ostream& out) const;
};
// Table of current disequalities
class exclusion_table {
typedef obj_pair_hashtable<expr, expr> table_t;
ast_manager& m;
table_t m_table;
expr_ref_vector m_lhs, m_rhs;
unsigned_vector m_limit;
public:
exclusion_table(ast_manager& m): m(m), m_lhs(m), m_rhs(m) {}
~exclusion_table() { }
bool empty() const { return m_table.empty(); }
void update(expr* e, expr* r);
bool contains(expr* e, expr* r) const;
void push_scope() { m_limit.push_back(m_lhs.size()); }
void pop_scope(unsigned num_scopes);
void display(std::ostream& out) const;
};
// Asserted or derived equality with dependencies
struct eq {
expr_ref m_lhs;
expr_ref m_rhs;
dependency* m_dep;
eq(expr_ref& l, expr_ref& r, dependency* d):
m_lhs(l), m_rhs(r), m_dep(d) {}
eq(eq const& other): m_lhs(other.m_lhs), m_rhs(other.m_rhs), m_dep(other.m_dep) {}
eq& operator=(eq const& other) { m_lhs = other.m_lhs; m_rhs = other.m_rhs; m_dep = other.m_dep; return *this; }
};
// asserted or derived disqequality with dependencies
struct ne {
bool m_solved;
expr_ref m_l, m_r;
expr_ref_vector m_lhs;
expr_ref_vector m_rhs;
literal_vector m_lits;
dependency* m_dep;
ne(expr_ref& l, expr_ref& r):
m_solved(false), m_l(l), m_r(r), m_lhs(l.get_manager()), m_rhs(r.get_manager()), m_dep(0) {
m_lhs.push_back(l);
m_rhs.push_back(r);
}
ne(ne const& other):
m_solved(other.m_solved), m_l(other.m_l), m_r(other.m_r), m_lhs(other.m_lhs), m_rhs(other.m_rhs), m_lits(other.m_lits), m_dep(other.m_dep) {}
ne& operator=(ne const& other) {
m_solved = other.m_solved;
m_l = other.m_l;
m_r = other.m_r;
m_lhs.reset(); m_lhs.append(other.m_lhs);
m_rhs.reset(); m_rhs.append(other.m_rhs);
m_lits.reset(); m_lits.append(other.m_lits);
m_dep = other.m_dep;
return *this;
}
bool is_solved() const { return m_solved; }
};
class pop_lit : public trail<theory_seq> {
unsigned m_idx;
literal m_lit;
public:
pop_lit(theory_seq& th, unsigned idx): m_idx(idx), m_lit(th.m_nqs[idx].m_lits.back()) {
th.m_nqs.ref(m_idx).m_lits.pop_back();
}
virtual void undo(theory_seq & th) { th.m_nqs.ref(m_idx).m_lits.push_back(m_lit); }
};
class push_lit : public trail<theory_seq> {
unsigned m_idx;
public:
push_lit(theory_seq& th, unsigned idx, literal lit): m_idx(idx) {
th.m_nqs.ref(m_idx).m_lits.push_back(lit);
}
virtual void undo(theory_seq & th) { th.m_nqs.ref(m_idx).m_lits.pop_back(); }
};
class set_lit : public trail<theory_seq> {
unsigned m_idx;
unsigned m_i;
literal m_lit;
public:
set_lit(theory_seq& th, unsigned idx, unsigned i, literal lit):
m_idx(idx), m_i(i), m_lit(th.m_nqs[idx].m_lits[i]) {
th.m_nqs.ref(m_idx).m_lits[i] = lit;
}
virtual void undo(theory_seq & th) { th.m_nqs.ref(m_idx).m_lits[m_i] = m_lit; }
};
class solved_ne : public trail<theory_seq> {
unsigned m_idx;
public:
solved_ne(theory_seq& th, unsigned idx) : m_idx(idx) { th.m_nqs.ref(idx).m_solved = true; }
virtual void undo(theory_seq& th) { th.m_nqs.ref(m_idx).m_solved = false; }
};
void mark_solved(unsigned idx);
class push_ne : public trail<theory_seq> {
unsigned m_idx;
public:
push_ne(theory_seq& th, unsigned idx, expr* l, expr* r) : m_idx(idx) {
th.m_nqs.ref(m_idx).m_lhs.push_back(l);
th.m_nqs.ref(m_idx).m_rhs.push_back(r);
}
virtual void undo(theory_seq& th) { th.m_nqs.ref(m_idx).m_lhs.pop_back(); th.m_nqs.ref(m_idx).m_rhs.pop_back(); }
};
class pop_ne : public trail<theory_seq> {
expr_ref m_lhs;
expr_ref m_rhs;
unsigned m_idx;
public:
pop_ne(theory_seq& th, unsigned idx):
m_lhs(th.m_nqs[idx].m_lhs.back(), th.m),
m_rhs(th.m_nqs[idx].m_rhs.back(), th.m),
m_idx(idx) {
th.m_nqs.ref(idx).m_lhs.pop_back();
th.m_nqs.ref(idx).m_rhs.pop_back();
}
virtual void undo(theory_seq& th) {
th.m_nqs.ref(m_idx).m_lhs.push_back(m_lhs);
th.m_nqs.ref(m_idx).m_rhs.push_back(m_rhs);
m_lhs.reset();
m_rhs.reset();
}
};
class set_ne : public trail<theory_seq> {
expr_ref m_lhs;
expr_ref m_rhs;
unsigned m_idx;
unsigned m_i;
public:
set_ne(theory_seq& th, unsigned idx, unsigned i, expr* l, expr* r):
m_lhs(th.m_nqs[idx].m_lhs[i], th.m),
m_rhs(th.m_nqs[idx].m_rhs[i], th.m),
m_idx(idx),
m_i(i) {
th.m_nqs.ref(idx).m_lhs[i] = l;
th.m_nqs.ref(idx).m_rhs[i] = r;
}
virtual void undo(theory_seq& th) {
th.m_nqs.ref(m_idx).m_lhs[m_i] = m_lhs;
th.m_nqs.ref(m_idx).m_rhs[m_i] = m_rhs;
m_lhs.reset();
m_rhs.reset();
}
};
class push_dep : public trail<theory_seq> {
dependency* m_dep;
unsigned m_idx;
public:
push_dep(theory_seq& th, unsigned idx, dependency* d): m_dep(th.m_nqs[idx].m_dep), m_idx(idx) {
th.m_nqs.ref(idx).m_dep = d;
}
virtual void undo(theory_seq& th) {
th.m_nqs.ref(m_idx).m_dep = m_dep;
}
};
class apply {
public:
virtual ~apply() {}
virtual void operator()(theory_seq& th) = 0;
};
class replay_length_coherence : public apply {
expr_ref m_e;
public:
replay_length_coherence(ast_manager& m, expr* e) : m_e(e, m) {}
virtual void operator()(theory_seq& th) {
th.check_length_coherence(m_e);
m_e.reset();
}
};
class replay_axiom : public apply {
expr_ref m_e;
public:
replay_axiom(ast_manager& m, expr* e) : m_e(e, m) {}
virtual void operator()(theory_seq& th) {
th.enque_axiom(m_e);
m_e.reset();
}
};
class push_replay : public trail<theory_seq> {
apply* m_apply;
public:
push_replay(apply* app): m_apply(app) {}
virtual void undo(theory_seq& th) {
th.m_replay.push_back(m_apply);
}
};
class pop_branch : public trail<theory_seq> {
expr_ref m_l, m_r;
public:
pop_branch(ast_manager& m, expr* l, expr* r): m_l(l, m), m_r(r, m) {}
virtual void undo(theory_seq& th) {
th.m_branch_start.erase(m_l, m_r);
m_l.reset();
m_r.reset();
}
};
void erase_index(unsigned idx, unsigned i);
struct stats {
stats() { reset(); }
void reset() { memset(this, 0, sizeof(stats)); }
unsigned m_num_splits;
unsigned m_num_reductions;
unsigned m_propagate_automata;
unsigned m_check_length_coherence;
unsigned m_branch_variable;
unsigned m_solve_nqs;
unsigned m_solve_eqs;
unsigned m_add_axiom;
};
ast_manager& m;
dependency_manager m_dm;
solution_map m_rep; // unification representative.
scoped_vector<eq> m_eqs; // set of current equations.
scoped_vector<ne> m_nqs; // set of current disequalities.
seq_factory* m_factory; // value factory
exclusion_table m_exclude; // set of asserted disequalities.
expr_ref_vector m_axioms; // list of axioms to add.
obj_hashtable<expr> m_axiom_set;
unsigned m_axioms_head; // index of first axiom to add.
bool m_incomplete; // is the solver (clearly) incomplete for the fragment.
obj_hashtable<expr> m_length; // is length applied
scoped_ptr_vector<apply> m_replay; // set of actions to replay
model_generator* m_mg;
th_rewriter m_rewrite;
seq_util m_util;
arith_util m_autil;
th_trail_stack m_trail_stack;
stats m_stats;
symbol m_prefix, m_suffix, m_contains_left, m_contains_right, m_accept, m_reject;
symbol m_tail, m_nth, m_seq_first, m_seq_last, m_indexof_left, m_indexof_right, m_aut_step;
symbol m_extract_prefix, m_at_left, m_at_right;
ptr_vector<expr> m_todo;
expr_ref_vector m_ls, m_rs, m_lhs, m_rhs;
// maintain automata with regular expressions.
scoped_ptr_vector<eautomaton> m_automata;
obj_map<expr, eautomaton*> m_re2aut;
// queue of asserted atoms
ptr_vector<expr> m_atoms;
unsigned_vector m_atoms_lim;
unsigned m_atoms_qhead;
bool m_new_solution; // new solution added
bool m_new_propagation; // new propagation to core
virtual final_check_status final_check_eh();
virtual bool internalize_atom(app* atom, bool) { return internalize_term(atom); }
virtual bool internalize_term(app*);
virtual void internalize_eq_eh(app * atom, bool_var v) {}
virtual void new_eq_eh(theory_var, theory_var);
virtual void new_diseq_eh(theory_var, theory_var);
virtual void assign_eh(bool_var v, bool is_true);
virtual bool can_propagate();
virtual void propagate();
virtual void push_scope_eh();
virtual void pop_scope_eh(unsigned num_scopes);
virtual void restart_eh();
virtual void relevant_eh(app* n);
virtual theory* mk_fresh(context* new_ctx) { return alloc(theory_seq, new_ctx->get_manager()); }
virtual char const * get_name() const { return "seq"; }
virtual theory_var mk_var(enode* n);
virtual void apply_sort_cnstr(enode* n, sort* s);
virtual void display(std::ostream & out) const;
virtual void collect_statistics(::statistics & st) const;
virtual model_value_proc * mk_value(enode * n, model_generator & mg);
virtual void init_model(model_generator & mg);
// final check
bool simplify_and_solve_eqs(); // solve unitary equalities
bool branch_variable(); // branch on a variable
bool split_variable(); // split a variable
bool is_solved();
bool check_length_coherence();
bool check_length_coherence(expr* e);
bool propagate_length_coherence(expr* e);
bool solve_eqs(unsigned start);
bool solve_eq(expr* l, expr* r, dependency* dep);
bool simplify_eq(expr* l, expr* r, dependency* dep);
bool solve_unit_eq(expr* l, expr* r, dependency* dep);
bool is_binary_eq(expr* l, expr* r, expr*& x, ptr_vector<expr>& xunits, ptr_vector<expr>& yunits, expr*& y);
bool solve_binary_eq(expr* l, expr* r, dependency* dep);
bool propagate_max_length(expr* l, expr* r, dependency* dep);
bool solve_nqs(unsigned i);
void solve_ne(unsigned i);
bool unchanged(expr* e, expr_ref_vector& es) const { return es.size() == 1 && es[0] == e; }
bool unchanged(expr* e, expr_ref_vector& es, expr* f, expr_ref_vector& fs) const {
return
(unchanged(e, es) && unchanged(f, fs)) ||
(unchanged(e, fs) && unchanged(e, fs));
}
// asserting consequences
void linearize(dependency* dep, enode_pair_vector& eqs, literal_vector& lits) const;
void propagate_lit(dependency* dep, literal lit) { propagate_lit(dep, 0, 0, lit); }
void propagate_lit(dependency* dep, unsigned n, literal const* lits, literal lit);
void propagate_eq(dependency* dep, enode* n1, enode* n2);
void propagate_eq(literal lit, expr* e1, expr* e2, bool add_to_eqs = false);
void set_conflict(dependency* dep, literal_vector const& lits = literal_vector());
obj_pair_map<expr, expr, unsigned> m_branch_start;
void insert_branch_start(expr* l, expr* r, unsigned s);
unsigned find_branch_start(expr* l, expr* r);
bool find_branch_candidate(unsigned& start, dependency* dep, expr_ref_vector const& ls, expr_ref_vector const& rs);
bool can_be_equal(unsigned szl, expr* const* ls, unsigned szr, expr* const* rs) const;
lbool assume_equality(expr* l, expr* r);
// variable solving utilities
bool occurs(expr* a, expr* b);
bool is_var(expr* b);
bool add_solution(expr* l, expr* r, dependency* dep);
bool is_nth(expr* a) const;
bool is_tail(expr* a, expr*& s, unsigned& idx) const;
expr_ref mk_nth(expr* s, expr* idx);
expr_ref mk_last(expr* e);
expr_ref canonize(expr* e, dependency*& eqs);
void canonize(expr* e, expr_ref_vector& es, dependency*& eqs);
expr_ref expand(expr* e, dependency*& eqs);
void add_dependency(dependency*& dep, enode* a, enode* b);
void get_concat(expr* e, ptr_vector<expr>& concats);
// terms whose meaning are encoded using axioms.
void enque_axiom(expr* e);
void deque_axiom(expr* e);
void add_axiom(literal l1, literal l2 = null_literal, literal l3 = null_literal, literal l4 = null_literal);
void add_indexof_axiom(expr* e);
void add_replace_axiom(expr* e);
void add_extract_axiom(expr* e);
void add_length_axiom(expr* n);
bool has_length(expr *e) const { return m_length.contains(e); }
void add_length(expr* e);
void enforce_length(enode* n);
void enforce_length_coherence(enode* n1, enode* n2);
void add_elim_string_axiom(expr* n);
void add_at_axiom(expr* n);
void add_in_re_axiom(expr* n);
literal mk_literal(expr* n);
literal mk_eq_empty(expr* n);
literal mk_equals(expr* a, expr* b);
void tightest_prefix(expr* s, expr* x, literal lit, literal lit2 = null_literal);
expr_ref mk_sub(expr* a, expr* b);
enode* ensure_enode(expr* a);
// arithmetic integration
bool lower_bound(expr* s, rational& lo);
bool upper_bound(expr* s, rational& hi);
bool get_length(expr* s, rational& val);
void mk_decompose(expr* e, expr_ref& head, expr_ref& tail);
expr_ref mk_skolem(symbol const& s, expr* e1, expr* e2 = 0, expr* e3 = 0, sort* range = 0);
bool is_skolem(symbol const& s, expr* e) const;
void set_incomplete(app* term);
// automata utilities
void propagate_in_re(expr* n, bool is_true);
eautomaton* get_automaton(expr* e);
literal mk_accept(expr* s, expr* idx, expr* re, expr* state);
literal mk_accept(expr* s, expr* idx, expr* re, unsigned i) { return mk_accept(s, idx, re, m_autil.mk_int(i)); }
bool is_accept(expr* acc) const { return is_skolem(m_accept, acc); }
bool is_accept(expr* acc, expr*& s, expr*& idx, expr*& re, unsigned& i, eautomaton*& aut) {
return is_acc_rej(m_accept, acc, s, idx, re, i, aut);
}
literal mk_reject(expr* s, expr* idx, expr* re, expr* state);
literal mk_reject(expr* s, expr* idx, expr* re, unsigned i) { return mk_reject(s, idx, re, m_autil.mk_int(i)); }
bool is_reject(expr* rej) const { return is_skolem(m_reject, rej); }
bool is_reject(expr* rej, expr*& s, expr*& idx, expr*& re, unsigned& i, eautomaton*& aut) {
return is_acc_rej(m_reject, rej, s, idx, re, i, aut);
}
bool is_acc_rej(symbol const& ar, expr* e, expr*& s, expr*& idx, expr*& re, unsigned& i, eautomaton*& aut);
expr_ref mk_step(expr* s, expr* tail, expr* re, unsigned i, unsigned j, expr* t);
bool is_step(expr* e, expr*& s, expr*& tail, expr*& re, expr*& i, expr*& j, expr*& t) const;
bool is_step(expr* e) const;
void propagate_step(literal lit, expr* n);
bool add_reject2reject(expr* rej);
bool add_accept2step(expr* acc);
bool add_step2accept(expr* step);
bool add_prefix2prefix(expr* e);
bool add_suffix2suffix(expr* e);
bool add_contains2contains(expr* e);
void ensure_nth(literal lit, expr* s, expr* idx);
bool canonizes(bool sign, expr* e);
void propagate_non_empty(literal lit, expr* s);
void propagate_is_conc(expr* e, expr* conc);
void propagate_acc_rej_length(literal lit, expr* acc_rej);
bool propagate_automata();
void add_atom(expr* e);
void new_eq_eh(dependency* dep, enode* n1, enode* n2);
// diagnostics
void display_equations(std::ostream& out) const;
void display_disequations(std::ostream& out) const;
void display_disequation(std::ostream& out, ne const& e) const;
void display_deps(std::ostream& out, dependency* deps) const;
public:
theory_seq(ast_manager& m);
virtual ~theory_seq();
// model building
app* mk_value(app* a);
};
};
#endif /* THEORY_SEQ_H_ */