lean4-htt/src/library/local_context.h
Leonardo de Moura 559211d284 perf(library/local_context): fix performance bottleneck at local_const
This is one of the performance problems at issue #1646.
The method `local_context::erase_user_name(local_decl const & d)` was
inefficient when there are many locals with the same user facing name.
For size 7 in the example described at issue #1646, the average size of the
declaration list was 400. Here are the runtimes for size 7

Before: 19.021 secs
After:  16.433 secs

There are more performance issues.
2017-06-06 10:01:08 -07:00

230 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
*/
#pragma once
#include "util/name_map.h"
#include "util/name_set.h"
#include "util/subscripted_name_set.h"
#include "kernel/expr.h"
namespace lean {
class local_decl {
public:
struct cell {
/*
<name> : <type> := <value>
m_pp_name is used for interacting with the user.
It may not be not unique.
*/
name m_name; /* this one is unique */
name m_pp_name;
expr m_type;
optional<expr> m_value;
binder_info m_bi;
unsigned m_idx;
MK_LEAN_RC(); // Declare m_rc counter
void dealloc();
cell(unsigned idx, name const & n, name const & pp_n, expr const & t, optional<expr> const & v,
binder_info const & bi);
};
private:
cell * m_ptr;
friend class local_context;
friend void initialize_local_context();
local_decl(unsigned idx, name const & n, name const & pp_n, expr const & t, optional<expr> const & v, binder_info const & bi);
local_decl(local_decl const & d, expr const & t, optional<expr> const & v);
public:
local_decl();
local_decl(local_decl const & s):m_ptr(s.m_ptr) { if (m_ptr) m_ptr->inc_ref(); }
local_decl(local_decl && s):m_ptr(s.m_ptr) { s.m_ptr = nullptr; }
~local_decl() { if (m_ptr) m_ptr->dec_ref(); }
local_decl & operator=(local_decl const & s) { LEAN_COPY_REF(s); }
local_decl & operator=(local_decl && s) { LEAN_MOVE_REF(s); }
friend bool is_eqp(local_decl const & a, local_decl const & b) { return a.m_ptr == b.m_ptr; }
name const & get_name() const { return m_ptr->m_name; }
name const & get_pp_name() const { return m_ptr->m_pp_name; }
expr const & get_type() const { return m_ptr->m_type; }
optional<expr> const & get_value() const { return m_ptr->m_value; }
binder_info const & get_info() const { return m_ptr->m_bi; }
expr mk_ref() const;
unsigned get_idx() const { return m_ptr->m_idx; }
};
bool is_local_decl_ref(expr const & e);
class metavar_context;
class local_context;
bool depends_on(expr const & e, metavar_context const & mctx, unsigned num, expr const * locals);
bool depends_on(local_decl const & d, metavar_context const & mctx, unsigned num, expr const * locals);
bool depends_on(expr const & e, metavar_context const & mctx, buffer<expr> const & locals);
bool depends_on(local_decl const & d, metavar_context const & mctx, buffer<expr> const & locals);
/* Similar to depends_on(expr const & e, metavar_context const & mctx, unsigned num, expr const * locals), but it
will also visit the value v of local definitions (x : t := v) if x occurs in e (directly or indirectly). */
bool depends_on(expr const & e, metavar_context const & mctx, local_context const & lctx, unsigned num, expr const * locals);
inline bool depends_on(expr const & e, metavar_context const & mctx, local_context const & lctx, expr const & local) {
return depends_on(e, mctx, lctx, 1, &local);
}
/* Create an unieq local_decl name.
This is a low-level function. The high-level methods
at local_context use this function internally. */
name mk_local_decl_name();
class metavar_context;
class local_context {
typedef unsigned_map<local_decl> idx2local_decl;
typedef rb_tree<unsigned, unsigned_cmp> unsigned_set;
unsigned m_next_idx;
name_map<local_decl> m_name2local_decl;
subscripted_name_set m_user_names;
name_map<unsigned_set> m_user_name2idxs;
idx2local_decl m_idx2local_decl;
optional<unsigned> m_instance_fingerprint;
friend class type_context;
/* Return the instance fingerprint for empty local_contexts */
static unsigned get_empty_instance_fingerprint() { return 31; }
void insert_user_name(local_decl const &d);
void erase_user_name(local_decl const &d);
local_context remove(buffer<expr> const & locals) const;
expr mk_local_decl(name const & n, name const & ppn, expr const & type,
optional<expr> const & value, binder_info const & bi);
static local_decl update_local_decl(local_decl const & d, expr const & t,
optional<expr> const & v) {
return local_decl(d, t, v);
}
public:
local_context():m_next_idx(0) {}
/* Return an empty local context with instance fingerprint set. */
static local_context mk_with_instance_fingerprint() {
local_context lctx;
lctx.m_instance_fingerprint = optional<unsigned>(get_empty_instance_fingerprint());
return lctx;
}
optional<unsigned> get_instance_fingerprint() const { return m_instance_fingerprint; }
bool empty() const { return m_idx2local_decl.empty(); }
expr mk_local_decl(expr const & type, binder_info const & bi = binder_info());
expr mk_local_decl(expr const & type, expr const & value);
expr mk_local_decl(name const & ppn, expr const & type, binder_info const & bi = binder_info());
expr mk_local_decl(name const & ppn, expr const & type, expr const & value);
/* Low-level version of the methods above.
\pre `n` was created using mk_local_decl_name
\pre there is no local_decl named `n` in this local_context. */
expr mk_local_decl(name const & n, name const & ppn, expr const & type, binder_info const & bi = binder_info());
expr mk_local_decl(name const & n, name const & ppn, expr const & type, expr const & value);
/** \brief Return the local declarations for the given reference.
\pre is_local_decl_ref(e) */
optional<local_decl> find_local_decl(expr const & e) const;
optional<local_decl> find_local_decl(name const & n) const;
local_decl const & get_local_decl(expr const & e) const;
local_decl const & get_local_decl(name const & n) const;
/** \brief Traverse local declarations based on the order they were created */
void for_each(std::function<void(local_decl const &)> const & fn) const;
optional<local_decl> find_if(std::function<bool(local_decl const &)> const & pred) const; // NOLINT
optional<local_decl> back_find_if(std::function<bool(local_decl const &)> const & pred) const; // NOLINT
/** \brief Return the most recently added local_decl \c d s.t. d.get_pp_name() == n
\remark This method is used to implement tactics such as 'revert'. */
optional<local_decl> find_local_decl_from_user_name(name const & n) const;
optional<local_decl> find_last_local_decl() const;
local_decl get_last_local_decl() const;
/** Return a local_decl_ref associated with the given name.
\pre get_local_decl(n) */
expr get_local(name const & n) const;
bool rename_user_name(name const & from, name const & to);
/** \brief Execute fn for each local declaration created after \c d. */
void for_each_after(local_decl const & d, std::function<void(local_decl const &)> const & fn) const;
/** \brief Return a non-none iff other local decls depends on \c d. If the result is not none,
then it is the name of the local decl that depends on d.
\pre \c d is in this local context. */
optional<local_decl> has_dependencies(local_decl const & d, metavar_context const & mctx) const;
/** \brief Return an unused hypothesis "user name" with the given prefix, the suffix is an
unsigned >= idx. */
name get_unused_name(name const & prefix, unsigned & idx) const;
name get_unused_name(name const & suggestion) const;
/** \brief Return true iff the given name is a hypothesis "user name". */
bool uses_user_name(name const & n) const;
/** \brief Remove the given local decl. */
void clear(local_decl const & d);
/** \brief Return true iff all locals in this context are in the set \c ls. */
bool is_subset_of(name_set const & ls) const;
/** \brief Return true iff all locals in this context are also in \c ctx. */
bool is_subset_of(local_context const & ctx) const;
void pop_local_decl();
/** \brief We say a local context is well-formed iff all local declarations only
contain local_decl references that were defined before them.
\remark This method is for debugging purposes. */
bool well_formed() const;
/** \brief Return true iff \c e is well-formed with respect to this local context.
That is, all local_decl references in \c e are defined in this context. */
bool well_formed(expr const & e) const;
format pp(formatter const & fmt, std::function<bool(local_decl const &)> const & pred) const; // NOLINT
format pp(formatter const & fmt) const { return pp(fmt, [](local_decl const &) { return true; }); }
/** \brief Replaced assigned metavariables with their values.
This method is a little bit hackish since it reuses the names and ids of
the existing local_decls. So, it may affect cached information.
This method is mainly used in the elaborator for reporting errors,
and for instantiating metavariables created by the elaborator before
invoking the tactic framework. */
local_context instantiate_mvars(metavar_context & ctx) const;
friend bool is_decl_eqp(local_context const & ctx1, local_context const & ctx2) {
return is_eqp(ctx1.m_name2local_decl, ctx2.m_name2local_decl);
}
friend bool equal_locals(local_context const & ctx1, local_context const & ctx2) {
return is_decl_eqp(ctx1, ctx2) || ctx1.m_name2local_decl.equal_keys(ctx2.m_name2local_decl);
}
/** \brief Erase inaccessible annotations from the local context.
This function is defined in the file library/equations_compiler/util.h.
It is a little bit hackish (like instantiate_mvars) since it reuses the names
and ids of existing local_decls. So, it may affect cached information.
This function is used in the elaborator before invoking the tactic framework. */
friend local_context erase_inaccessible_annotations(local_context const & lctx);
};
/** \brief Return true iff `e` contains a local_decl_ref that contains a value */
bool contains_let_local_decl(local_context const & lctx, expr const & e);
/** \brief Expand all local_decl_refs (that have values) in `e` */
expr zeta_expand(local_context const & lctx, expr const & e);
void initialize_local_context();
void finalize_local_context();
}