Make regex matching reentrant; update syntax during match

* src/lisp.h (compile_pattern): Remove prototype of
now-internal function.

* src/regex.c (POS_AS_IN_BUFFER): Consult gl_state instead of
re_match_object: the latter can change in Lisp.
(re_match_2_internal): Switch back to UPDATE_SYNTAX_* FROM
UPDATE_SYNTAX_FAST*, allowing calls into Lisp.

* src/regex.h (re_match_object): Uncomment declaration.

* src/search.c (struct regexp_cache): Add `busy' field.
(thaw_buffer_relocation): Delete; rely on unbind.
(compile_pattern_1): Assert pattern isn't busy.
(shrink_regexp_cache): Don't shrink busy patterns.
(clear_regexp_cache): Don't nuke busy patterns.
(unfreeze_pattern, freeze_pattern): New functions.
(compile_pattern): Return a regexp_cache pointer instead of the
re_pattern_buffer, allowing callers to use `freeze_pattern' if
needed.  Do not consider busy patterns as cache hit candidates;
error if we run out of non-busy cache entries.
(looking_at_1, fast_looking_at): Snapshot
Vinhibit_changing_match_data; mark pattern busy while we're
matching it; unbind.
(string_match_1, fast_string_match_internal)
(fast_c_string_match_ignore_case): Adjust for compile_pattern
return type.
(search_buffer_re): Regex code from old search_buffer moved here;
snapshot Vinhibit_changing_match_data; mark pattern busy while
we're matching it; unbind.
(search_buffer_non_re): Non-regex code from old search_buffer
moved here.
(search_buffer): Split into search_buffer_re,
search_buffer_non_re.
(syms_of_search): Staticpro re_match_object, even though we really
shouldn't have to.

* src/syntax.h (UPDATE_SYNTAX_TABLE_FORWARD_FAST):
(UPDATE_SYNTAX_TABLE_FAST): Remove.

* src/thread.h (struct thread_state): Remove m_re_match_object,
which is global again.  (It never needs to be preserved across
thread switch.)

1 files changed, 0 insertions, 9 deletions

diff --git a/src/thread.h b/src/thread.h
index 2c8914e1b28..c10e5ecb758 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -137,15 +137,6 @@ struct thread_state
   struct re_registers m_saved_search_regs;
 #define saved_search_regs (current_thread->m_saved_search_regs)
 
-  /* This is the string or buffer in which we
-     are matching.  It is used for looking up syntax properties.
-
-     If the value is a Lisp string object, we are matching text in that
-     string; if it's nil, we are matching text in the current buffer; if
-     it's t, we are matching text in a C string.  */
-  Lisp_Object m_re_match_object;
-#define re_match_object (current_thread->m_re_match_object)
-
   /* This member is different from waiting_for_input.
      It is used to communicate to a lisp process-filter/sentinel (via the
      function Fwaiting_for_user_input_p) whether Emacs was waiting