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https://github.com/Z3Prover/z3
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116 lines
3.1 KiB
C++
116 lines
3.1 KiB
C++
/*++
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Copyright (c) 2012 Microsoft Corporation
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Module Name:
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expr_safe_replace.cpp
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Abstract:
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Version of expr_replace/expr_substitution that is safe for quantifiers.
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Author:
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Nikolaj Bjorner (nbjorner) 2012-11-30
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Revision History:
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--*/
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#include "expr_safe_replace.h"
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#include "rewriter.h"
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void expr_safe_replace::insert(expr* src, expr* dst) {
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m_src.push_back(src);
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m_dst.push_back(dst);
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m_subst.insert(src, dst);
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}
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void expr_safe_replace::operator()(expr* e, expr_ref& res) {
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obj_map<expr,expr*> cache;
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ptr_vector<expr> todo, args;
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expr_ref_vector refs(m);
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todo.push_back(e);
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expr* a, *b, *d;
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todo.push_back(e);
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while (!todo.empty()) {
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a = todo.back();
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if (cache.contains(a)) {
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todo.pop_back();
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}
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else if (m_subst.find(a, b)) {
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cache.insert(a, b);
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todo.pop_back();
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}
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else if (is_var(a)) {
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cache.insert(a, a);
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todo.pop_back();
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}
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else if (is_app(a)) {
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app* c = to_app(a);
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unsigned n = c->get_num_args();
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args.reset();
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for (unsigned i = 0; i < n; ++i) {
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if (cache.find(c->get_arg(i), d)) {
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args.push_back(d);
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}
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else {
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todo.push_back(c->get_arg(i));
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}
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}
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if (args.size() == n) {
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b = m.mk_app(c->get_decl(), args.size(), args.c_ptr());
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refs.push_back(b);
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cache.insert(a, b);
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todo.pop_back();
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}
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}
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else {
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SASSERT(is_quantifier(a));
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quantifier* q = to_quantifier(a);
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expr_safe_replace replace(m);
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var_shifter shift(m);
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expr_ref new_body(m), src(m), dst(m), tmp(m);
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expr_ref_vector pats(m), nopats(m);
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unsigned num_decls = q->get_num_decls();
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for (unsigned i = 0; i < m_src.size(); ++i) {
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shift(m_src[i].get(), num_decls, src);
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shift(m_dst[i].get(), num_decls, dst);
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replace.insert(src, dst);
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}
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unsigned np = q->get_num_patterns();
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for (unsigned i = 0; i < np; ++i) {
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replace(q->get_pattern(i), tmp);
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pats.push_back(tmp);
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}
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np = q->get_num_no_patterns();
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for (unsigned i = 0; i < np; ++i) {
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replace(q->get_no_pattern(i), tmp);
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nopats.push_back(tmp);
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}
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replace(q->get_expr(), new_body);
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b = m.update_quantifier(q, pats.size(), pats.c_ptr(), nopats.size(), nopats.c_ptr(), new_body);
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refs.push_back(b);
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cache.insert(a, b);
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todo.pop_back();
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}
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}
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res = cache.find(e);
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}
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void expr_safe_replace::reset() {
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m_src.reset();
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m_dst.reset();
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m_subst.reset();
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}
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void expr_safe_replace::apply_substitution(expr* s, expr* def, expr_ref& t) {
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reset();
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insert(s, def);
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(*this)(t, t);
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reset();
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}
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