From: Alan Mackenzie <acm@muc.de>
Date: Sun, 16 Jun 2019 15:46:12 +0000 (+0000)
Subject: CC Mode: Remedy recent loss in performance
X-Git-Tag: emacs-27.0.90~2471
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=e6fb9a443f48d7bcf1f56ce2ea526c3fa5b732b0;p=emacs.git

CC Mode: Remedy recent loss in performance

* lisp/progmodes/cc-engine.el (c-back-over-member-initializers): call
c-parse-state outside of the narrowing operation.

* lisp/progmodes/cc-fonts.el (c-get-fontification-context)
(c-font-lock-cut-off-declarators): Replace calls to c-determine-limit with
crude position calculations for speed.
---

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 6598cc62c20..d3d7a1c5c0a 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -8611,10 +8611,11 @@ comment at the start of cc-engine.el for more info."
   ;; the function's arglist.  Otherwise return nil, leaving point unchanged.
   ;; LIMIT, if non-nil, is a limit for the backward search.
   (save-restriction
-    (if limit (narrow-to-region limit (point)))
     (let ((here (point))
-	  (paren-state (c-parse-state))
+	  (paren-state (c-parse-state))	; Do this outside the narrowing for
+					; performance reasons.
 	  pos level-plausible at-top-level res)
+      (if limit (narrow-to-region limit (point)))
       ;; Assume tentatively that we're at the top level.  Try to go back to the
       ;; colon we seek.
       (setq res
@@ -8637,7 +8638,8 @@ comment at the start of cc-engine.el for more info."
 
 	      (while (and (not (and level-plausible
 				    (setq at-top-level (c-at-toplevel-p))))
-			  (setq pos (c-pull-open-brace paren-state))) ; might be a paren.
+			  (setq pos (c-pull-open-brace paren-state)) ; might be a paren.
+			  (or (null limit) (>= pos limit)))
 		(setq level-plausible
 		      (catch 'level
 			(goto-char pos)
diff --git a/lisp/progmodes/cc-fonts.el b/lisp/progmodes/cc-fonts.el
index cef2015f430..269d2c90b79 100644
--- a/lisp/progmodes/cc-fonts.el
+++ b/lisp/progmodes/cc-fonts.el
@@ -1204,7 +1204,9 @@ casts and declarations are fontified.  Used on level 2 and higher."
 	  ((save-excursion
 	     (goto-char match-pos)
 	     (and (memq (char-before match-pos) '(?\( ?\,))
-		  (c-go-up-list-backward match-pos (c-determine-limit 500))
+		  (c-go-up-list-backward match-pos
+					  ; c-determine-limit is too slow, here.
+					 (max (- (point) 2000) (point-min)))
 		  (eq (char-after) ?\()
 		  (let ((type (c-get-char-property (point) 'c-type)))
 		    (or (memq type '(c-decl-arg-start c-decl-type-start))
@@ -1605,7 +1607,9 @@ casts and declarations are fontified.  Used on level 2 and higher."
 	  c-recognize-knr-p)		; Strictly speaking, bogus, but it
 					; speeds up lisp.h tremendously.
       (save-excursion
-	(when (not (c-back-over-member-initializers (c-determine-limit 2000)))
+	(when (not (c-back-over-member-initializers
+		    (max (- (point) 2000) (point-min)))) ; c-determine-limit
+							 ; is too slow, here.
 	  (unless (or (eobp)
 		      (looking-at "\\s(\\|\\s)"))
 	    (forward-char))