bug#60953: The :match predicate with large regexp in tree-sitter font-lock seems inefficient

[Dmitry Gutov <dgutov@yandex.ru>]

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On 02/02/2023 08:34, Eli Zaretskii wrote:
>> Date: Wed, 1 Feb 2023 23:20:50 +0200
>> Cc:casouri@gmail.com,60953@debbugs.gnu.org
>> From: Dmitry Gutov<dgutov@yandex.ru>
>>
>> On 01/02/2023 15:39, Eli Zaretskii wrote:
>>>> Please see the attachment.
>>>>
>>>> To note the numbers: the first patch does quite well to improve the
>>>> performance of modes which use :match in queries which match a lot of
>>>> nodes (e.g. rust-ts-mode or ruby-ts-mode). There boost in those was on
>>>> the order of 25%.
>>>>
>>>> The second one is longer, and the boost (on top of the first one) is
>>>> around 5-6%, stable. Not as impressive, but at least it brings :match's
>>>> performance a little above :pred's in my example.
>>> Fine by me, if Yuan also approves.
>> For emacs-29, right?
> Yes.

Please take a look at this additional patch on top of the other one. It 
is ok?

I just remembered that if we don't want to auto-anchor the regexp, then 
'looking-at' is not the appropriate semantic. So this switches to 
'search_buffer'.

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diff --git a/src/lisp.h b/src/lisp.h
index 70555b3ce91..1276285e2f2 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4802,6 +4802,9 @@ fast_c_string_match_ignore_case (Lisp_Object regexp,
 				       ptrdiff_t, ptrdiff_t *);
 extern ptrdiff_t find_before_next_newline (ptrdiff_t, ptrdiff_t,
 					   ptrdiff_t, ptrdiff_t *);
+extern EMACS_INT search_buffer (Lisp_Object, ptrdiff_t, ptrdiff_t,
+				ptrdiff_t, ptrdiff_t, EMACS_INT,
+				int, Lisp_Object, Lisp_Object, bool);
 extern void syms_of_search (void);
 extern void clear_regexp_cache (void);
 
diff --git a/src/search.c b/src/search.c
index dbc5a83946f..0bb52c03eef 100644
--- a/src/search.c
+++ b/src/search.c
@@ -68,9 +68,6 @@ #define REGEXP_CACHE_SIZE 20
 static EMACS_INT boyer_moore (EMACS_INT, unsigned char *, ptrdiff_t,
                               Lisp_Object, Lisp_Object, ptrdiff_t,
                               ptrdiff_t, int);
-static EMACS_INT search_buffer (Lisp_Object, ptrdiff_t, ptrdiff_t,
-                                ptrdiff_t, ptrdiff_t, EMACS_INT, int,
-                                Lisp_Object, Lisp_Object, bool);
 
 Lisp_Object re_match_object;
 
@@ -1510,7 +1507,7 @@ search_buffer_non_re (Lisp_Object string, ptrdiff_t pos,
   return result;
 }
 
-static EMACS_INT
+EMACS_INT
 search_buffer (Lisp_Object string, ptrdiff_t pos, ptrdiff_t pos_byte,
 	       ptrdiff_t lim, ptrdiff_t lim_byte, EMACS_INT n,
 	       int RE, Lisp_Object trt, Lisp_Object inverse_trt, bool posix)
diff --git a/src/treesit.c b/src/treesit.c
index 510170ca640..069fa3608bd 100644
--- a/src/treesit.c
+++ b/src/treesit.c
@@ -2491,7 +2491,8 @@ treesit_predicate_match (Lisp_Object args, struct capture_range captures)
   ZV = end_pos;
   ZV_BYTE = end_byte;
 
-  ptrdiff_t val = fast_looking_at (regexp, start_pos, start_byte, end_pos, end_byte, Qnil);
+  ptrdiff_t val = search_buffer (regexp, start_pos, start_byte, end_pos, end_byte,
+				 1, 1, Qnil, Qnil, false);
 
   BEGV = old_begv;
   BEGV_BYTE = old_begv_byte;