(c-state-literal-at): Prevent positions in macros finding their way into

c-state-nonlit-pos-cache.  Strengthen the comments.

(c-state-dump): New commented out diagnostic routine.

2 files changed, 46 insertions, 4 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 05c765e0881..e4b30dfa310 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2011-02-21  Alan Mackenzie  <acm@muc.de>
+
+        Fix bug #7930.
+        * progmodes/cc-engine.el (c-state-literal-at): Prevent positions
+        in macros finding their way into c-state-nonlit-pos-cache.
+        Strengthen the comments.
+        (c-state-dump): New commented out diagnostic routine.
+
 2011-02-21  Michael Albinus  <michael.albinus@gmx.de>
 
         * net/tramp.el (tramp-rfn-eshadow-setup-minibuffer): Do not use
diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index de1debd6456..654323e03e4 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -2023,9 +2023,9 @@ comment at the start of cc-engine.el for more info."
 
 (defvar c-state-nonlit-pos-cache nil)
 (make-variable-buffer-local 'c-state-nonlit-pos-cache)
-;; A list of buffer positions which are known not to be in a literal.  This is
-;; ordered with higher positions at the front of the list.  Only those which
-;; are less than `c-state-nonlit-pos-cache-limit' are valid.
+;; A list of buffer positions which are known not to be in a literal or a cpp
+;; construct.  This is ordered with higher positions at the front of the list.
+;; Only those which are less than `c-state-nonlit-pos-cache-limit' are valid.
 
 (defvar c-state-nonlit-pos-cache-limit 1)
 (make-variable-buffer-local 'c-state-nonlit-pos-cache-limit)
@@ -2056,6 +2056,12 @@ comment at the start of cc-engine.el for more info."
   ;; This function is almost the same as `c-literal-limits'.  It differs in
   ;; that it is a lower level function, and that it rigourously follows the
   ;; syntax from BOB, whereas `c-literal-limits' uses a "local" safe position.
+  ;;
+  ;; NOTE: This function manipulates `c-state-nonlit-pos-cache'.  This cache
+  ;; MAY NOT contain any positions within macros, since macros are frequently
+  ;; turned into comments by use of the `c-cpp-delimiter' category properties.
+  ;; We cannot rely on this mechanism whilst determining a cache pos since
+  ;; this function is also called from outwith `c-parse-state'.
   (save-restriction
     (widen)
     (save-excursion
@@ -2074,6 +2080,11 @@ comment at the start of cc-engine.el for more info."
                    here)
           (setq lit (c-state-pp-to-literal pos npos))
           (setq pos (or (cdr lit) npos)) ; end of literal containing npos.
+          (goto-char pos)
+          (when (and (c-beginning-of-macro) (/= (point) pos))
+            (c-syntactic-end-of-macro)
+            (or (eobp) (forward-char))
+            (setq pos (point)))
           (setq c-state-nonlit-pos-cache (cons pos c-state-nonlit-pos-cache)))
 
         (if (> pos c-state-nonlit-pos-cache-limit)
@@ -2158,7 +2169,7 @@ comment at the start of cc-engine.el for more info."
 ;; of fruitless backward scans.
 (defvar c-state-brace-pair-desert nil)
 (make-variable-buffer-local 'c-state-brace-pair-desert)
-;; Used only in `c-append-lower-brace-pair-to-state-cache'.  It is set when an
+;; Used only in `c-append-lower-brace-pair-to-state-cache'.  It is set when
 ;; that defun has searched backwards for a brace pair and not found one.  Its
 ;; value is either nil or a cons (PA . FROM), where PA is the position of the
 ;; enclosing opening paren/brace/bracket which bounds the backwards search (or
@@ -2843,6 +2854,29 @@ comment at the start of cc-engine.el for more info."
         c-state-old-cpp-end nil)
   (c-state-mark-point-min-literal))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Debugging routines to dump `c-state-cache' in a "replayable" form.
+;; (defmacro c-sc-de (elt)              ; "c-state-cache-dump-element"
+;;   `(format ,(concat "(setq " (symbol-name elt) " %s)    ") ,elt))
+;; (defmacro c-sc-qde (elt)             ; "c-state-cache-quote-dump-element"
+;;   `(format ,(concat "(setq " (symbol-name elt) " '%s)    ") ,elt))
+;; (defun c-state-dump ()
+;;   ;; For debugging.
+;;   ;(message
+;;   (concat
+;;    (c-sc-qde c-state-cache)
+;;    (c-sc-de c-state-cache-good-pos)
+;;    (c-sc-qde c-state-nonlit-pos-cache)
+;;    (c-sc-de c-state-nonlit-pos-cache-limit)
+;;    (c-sc-qde c-state-brace-pair-desert)
+;;    (c-sc-de c-state-point-min)
+;;    (c-sc-de c-state-point-min-lit-type)
+;;    (c-sc-de c-state-point-min-lit-start)
+;;    (c-sc-de c-state-min-scan-pos)
+;;    (c-sc-de c-state-old-cpp-beg)
+;;    (c-sc-de c-state-old-cpp-end)))
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
 (defun c-invalidate-state-cache-1 (here)
   ;; Invalidate all info on `c-state-cache' that applies to the buffer at HERE
   ;; or higher and set `c-state-cache-good-pos' accordingly.  The cache is