lean4-htt/src/library/abstract_expr.cpp
2016-06-23 15:17:25 -07:00

316 lines
10 KiB
C++

/*
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "util/hash.h"
#include "util/interrupt.h"
#include "kernel/expr_maps.h"
#include "kernel/instantiate.h"
#include "library/abstract_expr.h"
#include "library/cache_helper.h"
#include "library/fun_info.h"
namespace lean {
struct abstract_expr_cache {
environment m_env;
expr_map<unsigned> m_hash_cache;
expr_map<unsigned> m_weight_cache;
abstract_expr_cache(environment const & env):m_env(env) {}
environment const & env() const { return m_env; }
};
/* The abstract_expr_cache does not depend on the transparency mode */
typedef transparencyless_cache_compatibility_helper<abstract_expr_cache>
abstract_expr_cache_helper;
MK_THREAD_LOCAL_GET_DEF(abstract_expr_cache_helper, get_aech);
abstract_expr_cache & get_abstract_cache_for(type_context const & ctx) {
return get_aech().get_cache_for(ctx);
}
#define EASY_HASH(e) { \
switch (e.kind()) { \
case expr_kind::Constant: case expr_kind::Local: \
case expr_kind::Meta: case expr_kind::Sort: \
case expr_kind::Var: \
return e.hash(); \
default: \
break; \
} \
}
struct abstract_fn {
type_context & m_ctx;
buffer<expr> m_locals;
type_context::transparency_scope m_scope;
static void check_system() { ::lean::check_system("abstract expression operator"); }
abstract_fn(type_context & ctx):
m_ctx(ctx),
m_scope(m_ctx, transparency_mode::All) {}
expr instantiate_locals(expr const & e) {
return instantiate_rev(e, m_locals.size(), m_locals.data());
}
expr push_local(name const & pp_name, expr const & type) {
expr l = m_ctx.push_local(pp_name, instantiate_locals(type));
m_locals.push_back(l);
return l;
}
expr push_let(name const & pp_name, expr const & type, expr const & value) {
expr l = m_ctx.push_let(pp_name, instantiate_locals(type), instantiate_locals(value));
m_locals.push_back(l);
return l;
}
void pop() {
m_locals.pop_back();
}
};
struct abstract_hash_fn : public abstract_fn {
expr_map<unsigned> & m_cache;
abstract_hash_fn(type_context & ctx):
abstract_fn(ctx),
m_cache(get_abstract_cache_for(ctx).m_hash_cache) {
}
unsigned hash(expr const & e) {
EASY_HASH(e);
auto it = m_cache.find(e);
if (it != m_cache.end())
return it->second;
check_system();
unsigned r = 0;
switch (e.kind()) {
case expr_kind::Constant: case expr_kind::Local:
case expr_kind::Meta: case expr_kind::Sort:
case expr_kind::Var:
lean_unreachable();
case expr_kind::Lambda:
case expr_kind::Pi:
r = hash(binding_domain(e));
push_local(binding_name(e), binding_domain(e));
r = ::lean::hash(r, hash(binding_body(e)));
pop();
break;
case expr_kind::Let:
r = ::lean::hash(hash(let_type(e)), hash(let_value(e)));
push_let(let_name(e), let_type(e), let_value(e));
r = ::lean::hash(r, hash(let_body(e)));
pop();
break;
case expr_kind::Macro:
r = lean::hash(macro_num_args(e), [&](unsigned i) { return hash(macro_arg(e, i)); },
macro_def(e).hash());
break;
case expr_kind::App:
buffer<expr> args;
expr const & f = get_app_args(e, args);
r = hash(f);
fun_info info = get_fun_info(m_ctx, instantiate_locals(f), args.size());
unsigned i = 0;
for (param_info const & pinfo : info.get_params_info()) {
lean_assert(i < args.size());
if (!pinfo.is_inst_implicit() && !pinfo.is_prop()) {
r = ::lean::hash(r, hash(args[i]));
}
i++;
}
/* Remark: the property (i == args.size()) does not necessarily hold here.
This can happen whenever the arity of f depends on its arguments. */
break;
}
m_cache.insert(mk_pair(e, r));
return r;
}
unsigned operator()(expr const & e) {
return hash(e);
}
};
unsigned abstract_hash(type_context & ctx, expr const & e) {
EASY_HASH(e);
return abstract_hash_fn(ctx)(e);
}
#define EASY_WEIGHT(e) { \
switch (e.kind()) { \
case expr_kind::Constant: case expr_kind::Local: \
case expr_kind::Meta: case expr_kind::Sort: \
case expr_kind::Var: \
return 1; \
default: \
break; \
} \
}
/* TODO(Leo): this class is too similar to abstract_hash_fn, both are folding expr.
We should try to merge both implementations. */
struct abstract_weight_fn : public abstract_fn {
expr_map<unsigned> & m_cache;
abstract_weight_fn(type_context & ctx):
abstract_fn(ctx),
m_cache(get_abstract_cache_for(ctx).m_weight_cache) {}
unsigned weight(expr const & e) {
EASY_WEIGHT(e);
auto it = m_cache.find(e);
if (it != m_cache.end())
return it->second;
check_system();
unsigned r = 0;
switch (e.kind()) {
case expr_kind::Constant: case expr_kind::Local:
case expr_kind::Meta: case expr_kind::Sort:
case expr_kind::Var:
lean_unreachable();
case expr_kind::Lambda:
case expr_kind::Pi:
r = weight(binding_domain(e));
push_local(binding_name(e), binding_domain(e));
r += weight(binding_body(e));
pop();
break;
case expr_kind::Let:
r = weight(let_type(e));
r += weight(let_value(e));
push_let(let_name(e), let_type(e), let_value(e));
r += weight(let_body(e));
pop();
break;
case expr_kind::Macro:
r = 0;
for (unsigned i = 0; i < macro_num_args(e); i++)
r += weight(macro_arg(e, i));
break;
case expr_kind::App:
buffer<expr> args;
expr const & f = get_app_args(e, args);
r = weight(f);
fun_info info = get_fun_info(m_ctx, instantiate_locals(f), args.size());
unsigned i = 0;
for (param_info const & pinfo : info.get_params_info()) {
lean_assert(i < args.size());
if (!pinfo.is_inst_implicit() && !pinfo.is_prop()) {
r += weight(args[i]);
}
i++;
}
/* Remark: the property (i == args.size()) does not necessarily hold here.
This can happen whenever the arity of f depends on its arguments. */
break;
}
m_cache.insert(mk_pair(e, r));
return r;
}
unsigned operator()(expr const & e) {
return weight(e);
}
};
unsigned abstract_weight(type_context & ctx, expr const & e) {
EASY_WEIGHT(e);
return abstract_weight_fn(ctx)(e);
}
struct abstract_eq_fn : public abstract_fn {
abstract_eq_fn(type_context & ctx):
abstract_fn(ctx) {}
bool equal(expr const & a, expr const & b) {
if (is_eqp(a, b))
return true;
if (abstract_hash(m_ctx, a) != abstract_hash(m_ctx, b))
return false;
if (a.kind() != b.kind())
return false;
switch (a.kind()) {
case expr_kind::Var:
case expr_kind::Constant:
case expr_kind::Meta:
case expr_kind::Sort:
case expr_kind::Local:
return a == b;
case expr_kind::Lambda:
case expr_kind::Pi:
check_system();
if (!equal(binding_domain(a), binding_domain(b)))
return false;
push_local(binding_name(a), binding_domain(a));
if (!equal(binding_body(a), binding_body(b)))
return false;
pop();
return true;
case expr_kind::Let:
check_system();
if (!equal(let_type(a), let_type(b)) ||
!equal(let_value(a), let_value(b)))
return false;
push_let(let_name(a), let_type(a), let_value(a));
if (!equal(let_body(a), let_body(b)))
return false;
pop();
return true;
case expr_kind::Macro:
if (macro_def(a) != macro_def(b) || macro_num_args(a) != macro_num_args(b))
return false;
check_system();
for (unsigned i = 0; i < macro_num_args(a); i++) {
if (!equal(macro_arg(a, i), macro_arg(b, i)))
return false;
}
return true;
case expr_kind::App:
check_system();
buffer<expr> a_args;
buffer<expr> b_args;
expr const & a_fn = get_app_args(a, a_args);
expr const & b_fn = get_app_args(b, b_args);
if (a_args.size() != b_args.size() ||
!equal(a_fn, b_fn))
return false;
fun_info info = get_fun_info(m_ctx, instantiate_locals(a_fn), a_args.size());
unsigned i = 0;
for (param_info const & pinfo : info.get_params_info()) {
lean_assert(i < a_args.size());
lean_assert(i < b_args.size());
if (!pinfo.is_inst_implicit() && !pinfo.is_prop() && !equal(a_args[i], b_args[i]))
return false;
i++;
}
/* Remark: the property (i == a_args.size()) does not necessarily hold here.
This can happen whenever the arity of f depends on its arguments. */
return true;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
bool operator()(expr const & a, expr const & b) {
return equal(a, b);
}
};
bool abstract_eq(type_context & ctx, expr const & a, expr const & b) {
if (is_eqp(a, b))
return true;
return abstract_eq_fn(ctx)(a, b);
}
}