2 files changed, 46 insertions, 10 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 1d3c92c4468..778fe3dedd6 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,17 @@
+2013-01-09  Alan Mackenzie  <acm@muc.de>
+
+        Fix bugs in the c-parse-state mechanism.  Reuse some markers
+        instead of continually generating new ones.
+
+        * progmodes/cc-engine.el (c-state-old-cpp-beg-marker)
+        (c-state-old-cpp-end-marker): New variables.
+        (c-append-lower-brace-pair-to-state-cache): Start a backward
+        search for "}" definitively outside CPP constructs.
+        (c-remove-stale-state-cache): Inform the caller of a need to
+        search back for a brace pair in certain circumstances.
+        (c-state-maybe-marker): New macro.
+        (c-parse-state): Reuse markers when appropriate.
+
 2013-01-09  Glenn Morris  <rgm@gnu.org>
 
         * simple.el (execute-extended-command): Doc fix.
diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 6ffa67f59c1..560b66bf3b0 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -2464,8 +2464,12 @@ comment at the start of cc-engine.el for more info."
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Variables which keep track of preprocessor constructs.
+(defvar c-state-old-cpp-beg-marker nil)
+(make-variable-buffer-local 'c-state-old-cpp-beg-marker)
 (defvar c-state-old-cpp-beg nil)
 (make-variable-buffer-local 'c-state-old-cpp-beg)
+(defvar c-state-old-cpp-end-marker nil)
+(make-variable-buffer-local 'c-state-old-cpp-end-marker)
 (defvar c-state-old-cpp-end nil)
 (make-variable-buffer-local 'c-state-old-cpp-end)
 ;; These are the limits of the macro containing point at the previous call of
@@ -2653,13 +2657,21 @@ comment at the start of cc-engine.el for more info."
   ;; reduce the time wasted in repeated fruitless searches in brace deserts.
   (save-excursion
     (save-restriction
-      (let ((bra from) ce               ; Positions of "{" and "}".
-            new-cons
-            (cache-pos (c-state-cache-top-lparen)) ; might be nil.
-            (macro-start-or-from
-             (progn (goto-char from)
-                    (c-beginning-of-macro)
-                    (point))))
+      (let* (new-cons
+             (cache-pos (c-state-cache-top-lparen)) ; might be nil.
+             (macro-start-or-from
+              (progn (goto-char from)
+                     (c-beginning-of-macro)
+                     (point)))
+             (bra                       ; Position of "{".
+              ;; Don't start scanning in the middle of a CPP construct unless
+              ;; it contains HERE - these constructs, in Emacs, are "commented
+              ;; out" with category properties.
+              (if (eq (c-get-char-property macro-start-or-from 'category)
+                        'c-cpp-delimiter)
+                    macro-start-or-from
+                  from))
+             ce)                        ; Position of "}"
         (or upper-lim (setq upper-lim from))
 
         ;; If we're essentially repeating a fruitless search, just give up.
@@ -2899,7 +2911,9 @@ comment at the start of cc-engine.el for more info."
                   (point-max)
                 (min (point-max) c-state-old-cpp-beg)))
         (while (and c-state-cache (>= (c-state-cache-top-lparen) upper-lim))
+          (setq scan-back-pos (car-safe (car c-state-cache)))
           (setq c-state-cache (cdr c-state-cache)))
+
         ;; If `upper-lim' is inside the last recorded brace pair, remove its
         ;; RBrace and indicate we'll need to search backwards for a previous
         ;; brace pair.
@@ -3324,6 +3338,13 @@ comment at the start of cc-engine.el for more info."
      (c-with-cpps-commented-out
       (c-invalidate-state-cache-1 here)))))
 
+(defmacro c-state-maybe-marker (place marker)
+  ;; If PLACE is non-nil, return a marker marking it, otherwise nil.
+  ;; We (re)use MARKER.
+  `(and ,place
+        (or ,marker (setq ,marker (make-marker)))
+        (set-marker ,marker ,place)))
+
 (defun c-parse-state ()
   ;; This is a wrapper over `c-parse-state-1'.  See that function for a
   ;; description of the functionality and return value.
@@ -3350,9 +3371,10 @@ comment at the start of cc-engine.el for more info."
               (c-parse-state-1))
            (c-with-cpps-commented-out
             (c-parse-state-1))))
-      (setq c-state-old-cpp-beg (and here-cpp-beg (copy-marker here-cpp-beg t))
-            c-state-old-cpp-end (and here-cpp-end (copy-marker here-cpp-end t)))
-      )))
+      (setq c-state-old-cpp-beg
+            (c-state-maybe-marker here-cpp-beg c-state-old-cpp-beg-marker)
+            c-state-old-cpp-end
+            (c-state-maybe-marker here-cpp-end c-state-old-cpp-end-marker)))))
 
 ;; Debug tool to catch cache inconsistencies.  This is called from
 ;; 000tests.el.