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% vim: ft=mercury ts=4 sw=4 et
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% Copyright (C) 2007 The University of Melbourne.
% Copyright (C) 2014-2018 The Mercury team.
% This file is distributed under the terms specified in COPYING.LIB.
%--------------------------------------------------%
%
% File: table_statistics.m.
% Author: zs.
% Stability: low.
%
% This file is automatically imported, as if via ":- use_module", into every
% module that contains a `pragma memo' that asks the compiler to create
% a predicate for returning statistics about the memo table. It defines
% the data structure that this predicate will return, and some operations
% on this data structure.
%
%--------------------------------------------------%
%--------------------------------------------------%

:- module table_statistics.
:- interface.

:- import_module io.
:- import_module list.
:- import_module maybe.

:- type proc_table_statistics
    --->    proc_table_statistics(
                call_table_stats            :: table_stats_curr_prev,
                maybe_answer_table_stats    :: maybe(table_stats_curr_prev)
            ).

:- type table_stats_curr_prev
    --->    table_stats_curr_prev(
                current_stats               :: table_stats,
                stats_at_last_call          :: table_stats
            ).

:- type table_stats
    --->    table_stats(
                num_lookups                 :: int,
                num_lookups_is_dupl         :: int,
                step_statistics             :: list(table_step_stats)
            ).

    % The definition of this type be an enum whose implementation matches
    % the type MR_TableTrieStep in runtime/mercury_tabling.h. It should also
    % be kept in sync with the type table_trie_step in hlds_pred.m.
    %
:- type table_step_kind
    --->    table_step_dummy
    ;       table_step_int
    ;       table_step_char
    ;       table_step_string
    ;       table_step_float
    ;       table_step_enum
    ;       table_step_foreign_enum
    ;       table_step_general
    ;       table_step_general_addr
    ;       table_step_general_poly
    ;       table_step_general_poly_addr
    ;       table_step_typeinfo
    ;       table_step_typeclassinfo
    ;       table_step_promise_implied
    ;       table_step_int8
    ;       table_step_uint8
    ;       table_step_int16
    ;       table_step_uint16
    ;       table_step_int32
    ;       table_step_uint32
    ;       table_step_int64
    ;       table_step_uint64.

:- type table_step_stats
    --->    table_step_stats(
                table_step_var_name                 :: string,
                table_step_num_lookups              :: int,
                table_step_num_lookups_is_dupl      :: int,
                table_step_detail                   :: table_step_stat_details
            ).

:- type table_step_stat_details
    --->    step_stats_none
    ;       step_stats_start(
                start_num_node_allocs               :: int,
                start_num_node_bytes                :: int
            )
    ;       step_stats_enum(
                enum_num_node_allocs                :: int,
                enum_num_node_bytes                 :: int
            )
    ;       step_stats_hash(
                hash_num_table_allocs               :: int,
                hash_num_table_bytes                :: int,
                hash_num_link_chunk_allocs          :: int,
                hash_num_link_chunk_bytes           :: int,
                hash_num_num_key_compares_not_dupl  :: int,
                hash_num_num_key_compares_dupl      :: int,
                hash_num_resizes                    :: int,
                hash_resizes_num_old_entries        :: int,
                hash_resizes_num_new_entries        :: int
            )
    ;       step_stats_du(
                du_num_node_allocs                  :: int,
                du_num_node_bytes                   :: int,
                du_num_arg_lookups                  :: int,
                du_num_exist_lookups                :: int,

                du_enum_num_node_allocs             :: int,
                du_enum_num_node_bytes              :: int,

                du_hash_num_table_allocs            :: int,
                du_hash_num_table_bytes             :: int,
                du_hash_num_link_chunk_allocs       :: int,
                du_hash_num_link_chunk_bytes        :: int,
                du_hash_num_num_key_compares_not_dupl :: int,
                du_hash_num_num_key_compares_dupl   :: int,
                du_hash_num_resizes                 :: int,
                du_hash_resizes_num_old_entries     :: int,
                du_hash_resizes_num_new_entries     :: int
            )
    ;       step_stats_poly(
                poly_du_num_node_allocs             :: int,
                poly_du_num_node_bytes              :: int,
                poly_du_num_arg_lookups             :: int,
                poly_du_num_exist_lookups           :: int,

                poly_enum_num_node_allocs           :: int,
                poly_enum_num_node_bytes            :: int,

                poly_hash_num_table_allocs          :: int,
                poly_hash_num_table_bytes           :: int,
                poly_hash_num_link_chunk_allocs     :: int,
                poly_hash_num_link_chunk_bytes      :: int,
                poly_hash_num_num_key_compares_not_dupl :: int,
                poly_hash_num_num_key_compares_dupl :: int,
                poly_hash_num_resizes               :: int,
                poly_hash_resizes_num_old_entries   :: int,
                poly_hash_resizes_num_new_entries   :: int
            ).

:- func table_stats_difference(table_stats, table_stats) = table_stats.

:- pred write_table_stats(table_stats::in, io::di, io::uo) is det.
:- pred write_table_stats(io.text_output_stream::in, table_stats::in,
    io::di, io::uo) is det.

    % In grades that don't support tabling, all calls to get tabling stats
    % will return these dummy statistics.
    %
:- func dummy_proc_table_statistics = proc_table_statistics.

%--------------------------------------------------%