1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2019-2023, CWI, Amsterdam
    7                              SWI-Prolog Solutions b.v.
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(prolog_trace,
   37          [ trace/1,                            % :Spec
   38            trace/2,                            % :Spec, +Ports
   39            tracing/2,                          % :Spec, -Ports
   40            list_tracing/0,
   41            notraceall/0
   42          ]).   43:- autoload(library(apply),[maplist/2]).   44:- autoload(library(error),[instantiation_error/1]).   45:- autoload(library(prolog_wrap),[wrap_predicate/4]).   46:- autoload(library(prolog_code), [pi_head/2]).   47
   48
   49/** <module> Print access to predicates
   50
   51This library prints accesses to  specified   predicates  by wrapping the
   52predicate.
   53
   54@see  library(debug)  for  adding  conditional  print  statements  to  a
   55program.
   56*/
   57
   58:- meta_predicate
   59    trace(:),
   60    trace(:, +),
   61    tracing(:, -).   62
   63:- dynamic tracing_mask/2.   64:- volatile tracing_mask/2.   65
   66%!  trace(:Pred) is det.
   67%!  trace(:Pred, +PortSpec) is det.
   68%
   69%   Print passes through _ports_ of  specified   predicates.  Pred is a,
   70%   possible partial, specification of a predicate as it is also used be
   71%   spy/1 and similar predicates. Where   a full predicate specification
   72%   is of the shape `Module:Name/Arity` (or `//Arity for non-terminals),
   73%   both the module and arity may be   omitted in which case Pred refers
   74%   to all matching  predicates.  PortSpec  is   either  a  single  port
   75%   (`call`, `exit`, `fail` or `redo`), preceded with   `+`  or `-` or a
   76%   list  of  these.  The   predicate    modifies   the   current  trace
   77%   specification and then installs a suitable wrapper for the predicate
   78%   using wrap_predicate/4.  For example:
   79%
   80%   ```
   81%   ?- trace(append).
   82%   %     lists:append/2: [all]
   83%   %     lists:append/3: [all]
   84%   %     append/1: [all]
   85%   true.
   86%
   87%   ?- append([a,b], [c], L).
   88%    T [10] Call: lists:append([a, b], [c], _18032)
   89%    T [19] Call: lists:append([b], [c], _19410)
   90%    T [28] Call: lists:append([], [c], _20400)
   91%    T [28 +0.1ms] Exit: lists:append([], [c], [c])
   92%    T [19 +0.2ms] Exit: lists:append([b], [c], [b, c])
   93%    T [10 +0.5ms] Exit: lists:append([a, b], [c], [a, b, c])
   94%   L = [a, b, c].
   95%
   96%   ?- trace(append, -all).
   97%   %     lists:append/2: Not tracing
   98%   %     lists:append/3: Not tracing
   99%   %     append/1: Not tracing
  100%   ```
  101%
  102%   The text between [] indicates the call  depth (first number) and for
  103%   all ports except the `call` port  the   _wall_  time since the start
  104%   (call port) in milliseconds. Note that the instrumentation and print
  105%   time is included in the time. In   the example above the actual time
  106%   is about 0.00001ms on todays hardware.
  107
  108trace(Pred) :-
  109    trace(Pred, +all).
  110
  111trace(Pred, Spec) :-
  112    '$find_predicate'(Pred, Preds),
  113    Preds \== [],
  114    maplist(set_trace(Spec), Preds).
  115
  116set_trace(Spec, Pred) :-
  117    (   tracing_mask(Pred, Spec0)
  118    ->  true
  119    ;   Spec0 = 0
  120    ),
  121    modify(Spec, Spec0, Spec1),
  122    retractall(tracing_mask(Pred, _)),
  123    (   Spec1 == [] ; Spec1 == 0
  124    ->  true
  125    ;   asserta(tracing_mask(Pred, Spec1))
  126    ),
  127    mask_ports(Spec1, Ports),
  128    pi_head(Pred, Head0),
  129    (   predicate_property(Head0, imported_from(M))
  130    ->  requalify(Head0, M, Head)
  131    ;   Head = Head0
  132    ),
  133    (   Spec1 == 0
  134    ->  unwrap_predicate(Head, trace),
  135        print_message(informational, trace(Head, Ports))
  136    ;   wrapper(Spec1, Head, Wrapped, Wrapper),
  137        wrap_predicate(Head, trace, Wrapped, Wrapper),
  138        print_message(informational, trace(Head, Ports))
  139    ).
  140
  141requalify(Term, M, M:Plain) :-
  142    strip_module(Term, _, Plain).
  143
  144modify(Var, _, _) :-
  145    var(Var),
  146    !,
  147    instantiation_error(Var).
  148modify([], Spec, Spec) :-
  149    !.
  150modify([H|T], Spec0, Spec) :-
  151    !,
  152    modify(H, Spec0, Spec1),
  153    modify(T, Spec1, Spec).
  154modify(+Port, Spec0, Spec) :-
  155    !,
  156    port_mask(Port, Mask),
  157    Spec is Spec0 \/ Mask.
  158modify(-Port, Spec0, Spec) :-
  159    !,
  160    port_mask(Port, Mask),
  161    Spec is Spec0 /\ \Mask.
  162modify(Port, Spec0, Spec) :-
  163    port_mask(Port, Mask),
  164    Spec is Spec0 \/ Mask.
  165
  166port_mask(all,  0x0f).
  167port_mask(call, 0x01).
  168port_mask(exit, 0x02).
  169port_mask(redo, 0x04).
  170port_mask(fail, 0x08).
  171
  172mask_ports(0, []) :-
  173    !.
  174mask_ports(Pattern, [H|T]) :-
  175    is_masked(Pattern, H, Pattern1),
  176    mask_ports(Pattern1, T).
  177
  178wrapper(Ports, Head, Wrapped, Wrapper) :-
  179    wrapper(Ports, Head,
  180            #{frame:Frame, level:Level, start:Start},
  181            Wrapped, Wrapped1),
  182    Wrapper = (   prolog_current_frame(Frame),
  183                  prolog_frame_attribute(Frame, level, Level),
  184                  get_time(Start),
  185                  Wrapped1
  186              ).
  187
  188wrapper(0, _, _, Wrapped, Wrapped) :-
  189    !.
  190wrapper(Pattern, Head, Id, Wrapped, Call) :-
  191    is_masked(Pattern, call, Pattern1),
  192    !,
  193    wrapper(Pattern1, Head, Id, Wrapped, Call0),
  194    Call = (   print_message(debug, frame(Head, trace(call, Id))),
  195               Call0
  196           ).
  197wrapper(Pattern, Head, Id, Wrapped, Call) :-
  198    is_masked(Pattern, exit, Pattern1),
  199    !,
  200    wrapper(Pattern1, Head, Id, Wrapped, Call0),
  201    Call = (   Call0,
  202               print_message(debug, frame(Head, trace(exit, Id)))
  203           ).
  204wrapper(Pattern, Head, Id, Wrapped, Call) :-
  205    is_masked(Pattern, redo, Pattern1),
  206    !,
  207    wrapper(Pattern1, Head, Id, Wrapped, Call0),
  208    Call = (   call_cleanup(Call0, Det = true),
  209               (   Det == true
  210               ->  true
  211               ;   true
  212               ;   print_message(debug, frame(Head, trace(redo, Id))),
  213                   fail
  214               )
  215           ).
  216wrapper(Pattern, Head, Id, Wrapped, Call) :-
  217    is_masked(Pattern, fail, Pattern1),
  218    !,
  219    wrapper(Pattern1, Head, Id, Wrapped, Call0),
  220    Call = call((   call_cleanup(Call0, Det = true),
  221                    (   Det == true
  222                    ->  !
  223                    ;   true
  224                    )
  225                ;   print_message(debug, frame(Head, trace(fail, Id))),
  226                    fail
  227                )).
  228
  229is_masked(Pattern0, Port, Pattern) :-
  230    port_mask(Port, Mask),
  231    Pattern0 /\ Mask =:= Mask,
  232    !,
  233    Pattern is Pattern0 /\ \Mask.
  234
  235%!  tracing(:Spec, -Ports)
  236%
  237%   True if Spec is traced using Ports
  238
  239tracing(Spec, Ports) :-
  240    tracing_mask(Spec, Mask),
  241    mask_ports(Mask, Ports).
  242
  243%!  list_tracing.
  244%
  245%   List predicates we are currently tracing
  246
  247list_tracing :-
  248    PI = _:_,
  249    findall(trace(Head, Ports), (tracing(PI, Ports), pi_head(PI, Head)), Tracing),
  250    print_message(informational, tracing(Tracing)).
  251
  252:- multifile
  253    prolog_debug_tools:debugging_hook/0.  254
  255prolog_debug_tools:debugging_hook :-
  256    (   tracing(_:_, _)
  257    ->  list_tracing
  258    ).
  259
  260
  261%!  notraceall is det.
  262%
  263%   Remove all trace points
  264
  265notraceall :-
  266    forall(tracing(M:Spec, _Ports),
  267           trace(M:Spec, -all))