82 lines
2.5 KiB
C++
82 lines
2.5 KiB
C++
/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include <tuple>
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#include <unordered_set>
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#include <functional>
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#include "util/buffer.h"
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#include "util/interrupt.h"
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#include "kernel/max_sharing.h"
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namespace lean {
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/**
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\brief Implementation of the functional object for creating expressions with maximally
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shared sub-expressions.
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*/
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struct max_sharing_fn::imp {
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typedef typename std::unordered_set<expr, expr_hash, std::equal_to<expr>> expr_cache;
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expr_cache m_cache;
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void cache(expr const & a) {
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a.raw()->set_max_shared();
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m_cache.insert(a);
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}
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expr apply(expr const & a) {
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check_system("max_sharing");
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auto r = m_cache.find(a);
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if (r != m_cache.end()) {
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lean_assert((*r).raw()->max_shared());
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return *r;
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}
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if (a.raw()->max_shared()) {
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m_cache.insert(a);
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return a;
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}
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expr res;
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switch (a.kind()) {
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case expr_kind::Constant: case expr_kind::Var:
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case expr_kind::Sort: case expr_kind::Macro:
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res = a;
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break;
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case expr_kind::Pair:
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res = update_pair(a, apply(pair_first(a)), apply(pair_second(a)), apply(pair_type(a)));
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break;
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case expr_kind::Fst: case expr_kind::Snd:
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res = update_proj(a, apply(proj_arg(a)));
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break;
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case expr_kind::App:
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res = update_app(a, apply(app_fn(a)), apply(app_arg(a)));
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break;
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case expr_kind::Sigma: case expr_kind::Lambda: case expr_kind::Pi:
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res = update_binder(a, apply(binder_domain(a)), apply(binder_body(a)));
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break;
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case expr_kind::Let:
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res = update_let(a, apply(let_type(a)), apply(let_value(a)), apply(let_body(a)));
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break;
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case expr_kind::Meta: case expr_kind::Local:
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res = update_mlocal(a, apply(mlocal_type(a)));
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break;
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}
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cache(res);
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return res;
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}
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expr operator()(expr const & a) { return apply(a); }
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};
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max_sharing_fn::max_sharing_fn():m_ptr(new imp) {}
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max_sharing_fn::~max_sharing_fn() {}
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expr max_sharing_fn::operator()(expr const & a) { return (*m_ptr)(a); }
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void max_sharing_fn::clear() { m_ptr->m_cache.clear(); }
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expr max_sharing(expr const & a) {
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if (a.raw()->max_shared())
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return a;
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else
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return max_sharing_fn::imp()(a);
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}
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}
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