lean2/src/library/fun_info_manager.cpp

183 lines
6.3 KiB
C++

/*
Copyright (c) 2015 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <algorithm>
#include "kernel/for_each_fn.h"
#include "kernel/instantiate.h"
#include "kernel/abstract.h"
#include "library/replace_visitor.h"
#include "library/fun_info_manager.h"
namespace lean {
fun_info_manager::fun_info_manager(type_context & ctx):
m_ctx(ctx) {
}
list<unsigned> fun_info_manager::collect_deps(expr const & type, buffer<expr> const & locals) {
buffer<unsigned> deps;
for_each(type, [&](expr const & e, unsigned) {
if (m_ctx.is_tmp_local(e)) {
unsigned idx;
for (idx = 0; idx < locals.size(); idx++)
if (locals[idx] == e)
break;
if (idx < locals.size() && std::find(deps.begin(), deps.end(), idx) == deps.end())
deps.push_back(idx);
}
return has_local(e); // continue the search only if e has locals
});
std::sort(deps.begin(), deps.end());
return to_list(deps);
}
auto fun_info_manager::get(expr const & e) -> fun_info {
if (auto r = m_fun_info.find(e))
return *r;
expr type = m_ctx.infer(e);
buffer<param_info> info;
buffer<expr> locals;
while (is_pi(type)) {
expr local = m_ctx.mk_tmp_local_from_binding(type);
expr local_type = m_ctx.infer(local);
expr new_type = m_ctx.whnf(instantiate(binding_body(type), local));
bool is_prop = m_ctx.is_prop(local_type);
bool is_sub = is_prop;
bool is_dep = !closed(binding_body(type));
if (!is_sub) {
// TODO(Leo): check if the following line is a performance bottleneck.
is_sub = static_cast<bool>(m_ctx.mk_subsingleton_instance(local_type));
}
info.emplace_back(binding_info(type).is_implicit(),
binding_info(type).is_inst_implicit(),
is_prop, is_sub, is_dep, collect_deps(local_type, locals));
locals.push_back(local);
type = new_type;
}
fun_info r(info.size(), to_list(info), collect_deps(type, locals));
m_fun_info.insert(e, r);
return r;
}
auto fun_info_manager::get(expr const & e, unsigned nargs) -> fun_info {
auto r = get(e);
lean_assert(nargs <= r.get_arity());
if (nargs == r.get_arity()) {
return r;
} else {
buffer<param_info> pinfos;
to_buffer(r.get_params_info(), pinfos);
buffer<unsigned> rdeps;
to_buffer(r.get_dependencies(), rdeps);
for (unsigned i = nargs; i < pinfos.size(); i++) {
for (auto d : pinfos[i].get_dependencies()) {
if (std::find(rdeps.begin(), rdeps.end(), d) == rdeps.end())
rdeps.push_back(d);
}
}
pinfos.shrink(nargs);
return fun_info(nargs, to_list(pinfos), to_list(rdeps));
}
}
struct replace_fn : public replace_visitor {
fun_info_manager & m_infom;
type_context & m_ctx;
unsigned m_num;
expr const * m_from;
expr const * m_to;
struct failed {};
replace_fn(fun_info_manager & infom, unsigned n, expr const * ts, expr const * rs):
m_infom(infom), m_ctx(infom.ctx()), m_num(n), m_from(ts), m_to(rs) {}
virtual expr visit(expr const & e) {
for (unsigned i = 0; i < m_num; i++) {
if (e == m_from[i])
return m_to[i];
}
return replace_visitor::visit(e);
}
virtual expr visit_mlocal(expr const & e) {
return e;
}
virtual expr visit_binding(expr const & b) {
expr new_domain = visit(binding_domain(b));
expr l = m_ctx.mk_tmp_local(binding_name(b), new_domain, binding_info(b));
expr new_body = abstract(visit(instantiate(binding_body(b), l)), l);
return update_binding(b, new_domain, new_body);
}
virtual expr visit_app(expr const & e) {
buffer<expr> args;
expr f = get_app_args(e, args);
expr new_f = visit(f);
fun_info info = m_infom.get(f);
if (info.get_arity() < args.size())
throw failed();
auto ps_info = info.get_params_info();
bool modified = f != new_f;
buffer<expr> new_args;
buffer<bool> to_check;
bool has_to_check = false;
for (expr const & arg : args) {
expr new_arg = visit(arg);
auto pinfo = head(ps_info);
bool c = false;
if (modified) {
// if not argument has been modified, then there is nothing to be checked
for (unsigned idx : pinfo.get_dependencies()) {
lean_assert(idx < new_args.size());
if (args[idx] != new_args[idx]) {
c = true;
has_to_check = true;
break;
}
}
}
if (new_arg != arg) {
modified = true;
}
to_check.push_back(c);
new_args.push_back(new_arg);
ps_info = tail(ps_info);
}
lean_assert(args.size() == new_args.size());
if (!modified)
return e;
expr new_e = mk_app(new_f, new_args);
if (has_to_check) {
lean_assert(to_check.size() == new_args.size());
expr it = new_e;
unsigned i = to_check.size();
while (i > 0) {
--i;
expr const & fn = app_fn(it);
if (to_check[i]) {
expr fn_type = m_ctx.whnf(m_ctx.infer(fn));
if (!is_pi(fn_type))
throw failed();
expr arg_type = m_ctx.infer(app_arg(it));
if (!m_ctx.is_def_eq(binding_domain(fn_type), arg_type))
throw failed();
}
it = fn;
}
}
return new_e;
}
};
optional<expr> replace(fun_info_manager & infom, expr const & e, unsigned n, expr const * ts, expr const * rs) {
try {
return some_expr(replace_fn(infom, n, ts, rs)(e));
} catch (replace_fn::failed &) {
return none_expr();
}
}
}