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wip: term_graph::project and term_graph::solve

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This commit is contained in:
Arie Gurfinkel 2018-06-11 17:38:14 -07:00
parent 7714d05c1a
commit 771d3b1349
2 changed files with 136 additions and 41 deletions
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134
src/qe/qe_term_graph.cpp
View file

@ -22,6 +22,7 @@ Notes:
#include "ast/ast_pp.h"
#include "ast/ast_util.h"
#include "ast/for_each_expr.h"
#include "ast/occurs.h"
#include "qe/qe_term_graph.h"
namespace qe {
@ -64,9 +65,9 @@ namespace qe {
m_children.push_back(t);
}
}
~term() {}
class parents {
term const& t;
public:
@ -167,9 +168,9 @@ namespace qe {
arith_term_graph_plugin(term_graph &g) :
term_graph_plugin (g.get_ast_manager().mk_family_id("arith")),
m_g(g), m(g.get_ast_manager()), m_arith(m) {(void)m_g;}
virtual ~arith_term_graph_plugin() {}
bool mk_eq_core (expr *_e1, expr *_e2, expr_ref &res) {
expr *e1, *e2;
e1 = _e1;
@ -384,7 +385,7 @@ namespace qe {
SASSERT(res);
return res;
}
void term_graph::internalize_eq(expr *a1, expr* a2) {
SASSERT(m_merge.empty());
merge(*internalize_term(a1), *internalize_term(a2));
@ -414,17 +415,17 @@ namespace qe {
void term_graph::merge(term &t1, term &t2) {
// -- merge might invalidate term2app cache
m_term2app.reset();
m_pinned.reset();
m_pinned.reset();
term *a = &t1.get_root();
term *b = &t2.get_root();
if (a == b) return;
if (a->get_class_size() > b->get_class_size()) {
std::swap(a, b);
}
// Remove parents of it from the cg table.
for (term* p : term::parents(b)) {
if (!p->is_marked()) {
@ -630,7 +631,9 @@ namespace qe {
return result;
}
expr_ref_vector term_graph::project(func_decl_ref_vector const& decls, bool exclude) {
void term_graph::project_core(func_decl_ref_vector const& decls,
bool exclude,
expr_ref_vector &result) {
u_map<bool> _decls;
for (func_decl* f : decls) _decls.insert(f->get_id(), true);
// - propagate representatives up over parents.
@ -639,10 +642,6 @@ namespace qe {
// - produce other literals over represented classes
// (walk disequalities in m_lits and represent lhs/rhs over decls or excluding decls)
expr_ref_vector result(m);
m_term2app.reset();
m_pinned.reset();
obj_hashtable<expr> eqs;
expr_ref eq(m);
ptr_vector<term> worklist;
@ -666,7 +665,7 @@ namespace qe {
if (!pure) continue;
// ensure that the root has a representative
// either by looking up cached version,
// either by looking up cached version,
// computing it for the first time, or
// inheriting pure.
expr* rep = nullptr;
@ -682,7 +681,10 @@ namespace qe {
}
bool update_rep = false;
// Add equations between pure and rep,
// AG: can rep be null at this point?
// AG: why mk_pure(root) is guaranteed to return non-null?
// Add equations between pure and rep,
// optionally swap the roles of rep and pure if
// pure makes a better representative.
if (rep != pure) {
@ -697,7 +699,7 @@ namespace qe {
}
}
// update the worklist if this is the first
// update the worklist if this is the first
// representative or pure was swapped into rep.
if (!has_rep || update_rep) {
for (term * p : term::parents(root)) {
@ -709,19 +711,107 @@ namespace qe {
}
}
}
// Here we could also walk equivalence classes that contain interpreted values by sort and
// extract disequalities bewteen non-unique value representatives.
// these disequalities are implied and can be mined using other means, such as
// theory aware core minimization
reset_marks();
}
expr_ref_vector term_graph::project(func_decl_ref_vector const& decls, bool exclude) {
expr_ref_vector result(m);
m_term2app.reset();
m_pinned.reset();
project_core(decls, exclude, result);
// walk other predicates than equalities
for (expr* e : m_lits) {
if (!m.is_eq(e) && m_term2app.find(get_term(e)->get_root().get_id(), e)) {
result.push_back(e);
}
}
// Here we could also walk equivalence classes that contain interpreted values by sort and
// extract disequalities bewteen non-unique value representatives.
// these disequalities are implied and can be mined using other means, such as
// theory aware core minimization
m_term2app.reset();
m_pinned.reset();
return result;
}
bool term_graph::is_solved_eq(expr *_lhs, expr* _rhs) {
if (!is_app(_lhs) || !is_app(_rhs)) return false;
app *lhs, *rhs;
lhs = ::to_app(_lhs);
rhs = ::to_app(_rhs);
if (rhs->get_num_args() > 0) return false;
if (rhs->get_family_id() != null_family_id) return false;
return !occurs(rhs, lhs);
}
void term_graph::solve_core(func_decl_ref_vector const &decls, bool exclude,
expr_ref_vector &result) {
u_map<bool> _decls;
for (func_decl* f : decls) _decls.insert(f->get_id(), true);
obj_hashtable<expr> eqs;
expr_ref eq(m);
ptr_vector<term> worklist;
for (term * t : m_terms) {
worklist.push_back(t);
t->set_mark(true);
}
while (!worklist.empty()) {
term* t = worklist.back();
worklist.pop_back();
t->set_mark(false);
if (m_term2app.contains(t->get_id()))
continue;
term &root = t->get_root();
bool has_rep = m_term2app.contains(root.get_id());
expr *pure = mk_pure(*t);
if (!pure) continue;
if (has_rep) {
// add equality if needed
expr* rep = m_term2app.find(root.get_id());
if (exclude != _decls.contains(t->get_decl_id()) || !is_solved_eq(rep, pure)) {
eq = m.mk_eq(rep, pure);
if (!eqs.contains(eq)) {
eqs.insert(eq);
result.push_back(eq);
}
}
}
else {
// let pure be the representative
m_term2app.insert(root.get_id(), pure);
// schedule parents of root to be processed again
for (term * p : term::parents(root)) {
if (!p->is_marked()) {
p->set_mark(true);
worklist.push_back(p);
}
}
SASSERT(false);
// TBD: deal with root
}
}
reset_marks();
}
expr_ref_vector term_graph::solve(func_decl_ref_vector const &decls, bool exclude) {
expr_ref_vector result(m);
m_term2app.reset();
m_pinned.reset();
project_core(decls, exclude, result);
solve_core(decls, exclude, result);
// walk other predicates than equalities
for (expr* e : m_lits) {
if (!m.is_eq(e) && m_term2app.find(get_term(e)->get_root().get_id(), e)) {
result.push_back(e);
}
}
m_term2app.reset();
m_pinned.reset();
return result;
}

43
src/qe/qe_term_graph.h
View file

@ -33,11 +33,11 @@ namespace qe {
virtual ~term_graph_plugin() {}
family_id get_family_id() const {return m_id;}
/// Process (and potentially augment) a literal
virtual expr_ref process_lit (expr *lit) = 0;
};
class term_graph {
struct term_hash { unsigned operator()(term const* t) const; };
@ -45,62 +45,67 @@ namespace qe {
ast_manager & m;
ptr_vector<term> m_terms;
expr_ref_vector m_lits; // NSB: expr_ref_vector?
u_map<term* > m_app2term;
u_map<term* > m_app2term;
ast_ref_vector m_pinned;
u_map<expr*> m_term2app;
plugin_manager<term_graph_plugin> m_plugins;
ptr_hashtable<term, term_hash, term_eq> m_cg_table;
vector<std::pair<term*,term*>> m_merge;
void merge(term &t1, term &t2);
void merge_flush();
term *mk_term(expr *t);
term *get_term(expr *t);
term *internalize_term(expr *t);
void internalize_eq(expr *a1, expr *a2);
void internalize_lit(expr *lit);
bool is_internalized(expr *a);
bool term_lt(term const &t1, term const &t2);
void pick_root (term &t);
void pick_roots();
void reset_marks();
expr* mk_app_core(expr* a);
expr_ref mk_app(term const &t);
expr* mk_pure(term& t);
expr_ref mk_app(expr *a);
void mk_equalities(term const &t, expr_ref_vector &out);
void mk_all_equalities(term const &t, expr_ref_vector &out);
void display(std::ostream &out);
void display(std::ostream &out);
void project_core(func_decl_ref_vector const &decls, bool exclude, expr_ref_vector &result);
void solve_core(func_decl_ref_vector const &decls, bool exclude, expr_ref_vector &result);
bool is_solved_eq(expr *lhs, expr *rhs);
public:
term_graph(ast_manager &m);
~term_graph();
ast_manager& get_ast_manager() const { return m;}
void add_lit(expr *lit);
void add_lit(expr *lit);
void add_lits(expr_ref_vector const &lits) { for (expr* e : lits) add_lit(e); }
void add_eq(expr* a, expr* b) { internalize_eq(a, b); }
void reset();
// deprecate?
void to_lits(expr_ref_vector &lits, bool all_equalities = false);
expr_ref to_app();
expr_ref to_app();
/**
* Return literals obtained by projecting added literals
* onto the vocabulary of decls (if exclude is false) or outside the
* Return literals obtained by projecting added literals
* onto the vocabulary of decls (if exclude is false) or outside the
* vocabulary of decls (if exclude is true).
*/
expr_ref_vector project(func_decl_ref_vector const& decls, bool exclude);
expr_ref_vector solve(func_decl_ref_vector const& decls, bool exclude);
};
}