From: Alan Mackenzie <acm@muc.de>
Date: Sun, 20 Oct 2019 16:55:26 +0000 (+0000)
Subject: Optimize c-crosses-statement-barrier-p for large blocks of comment.
X-Git-Tag: emacs-27.0.90~951
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=5ddbd8d191e7e38167a63728c6ead5a6401c63f6;p=emacs.git

Optimize c-crosses-statement-barrier-p for large blocks of comment.

This fixes bug #18134.

* lisp/progmodes/cc-engine.el (c-crosses-statement-barrier-p): Give a limit
to the c-backward-syntactic-ws which is searching for a virtual semicolon.  In
the main loop, Use c-forward-syntactic-ws to skip blocks of comments.
---

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 8d92b26ebd0..cceb58c290a 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -1468,10 +1468,14 @@ comment at the start of cc-engine.el for more info."
 		     (progn
 		       (if (setq lit-start (c-literal-start from)) ; Have we landed in a string/comment?
 			   (goto-char lit-start))
-		       (c-backward-syntactic-ws) ; ? put a limit here, maybe?
+		       (c-backward-syntactic-ws (c-point 'bopl))
 		       (setq vsemi-pos (point))
 		       (c-at-vsemi-p))))
 	      (throw 'done vsemi-pos))
+	     ;; Optimize for large blocks of comments.
+	     ((progn (c-forward-syntactic-ws to)
+		     (>= (point) to))
+	      (throw 'done nil))
 	     ;; In a string/comment?
 	     ((setq lit-range (c-literal-limits from))
 	      (goto-char (cdr lit-range)))