Rationalize the use of c-new-BEG and c-new-END in CC Mode.

Remove the now redundant c-old-BOM and c-old-EOM.

* lisp/progmodes/cc-engine.el (c-macro-cache-syntactic): Change and simplify
meaning.
(c-macro-cache-no-comment): New variable.
(c-invalidate-macro-cache, c-beginning-of-macro, c-end-of-macro): incorporate
the new c-macro-cache-no-comment.
(c-syntactic-end-of-macro): Make better use of c-macro-cache-syntactic.
(c-no-comment-end-of-macro): New function.

* lisp/progmodes/cc-langs.el (c-before-font-lock-functions): Add
c-extend-font-lock-region-for-macros to C/C++/ObjC value.

* lisp/progmodes/cc-mode.el (c-old-BOM, c-old-EOM): Remove.
(c-extend-region-for-CPP): Put results in c-new-BEG/END rather than
c-old-BOM/EOM.
(c-extend-font-lock-region-for-macros): Simplify meaning, no longer returning
a cons for the new region, since the function is now called as an after-change
function.  No longer adjust c-new-END for the length of inserted/deleted
text.  Move the size restrictions on macros to here from
c-neutralize-syntax-in-and-mark-CPP.
(c-neutralize-syntax-in-and-mark-CPP): No longer adjust c-new-BEG/END here.
Use c-no-comment-end-of-macro rather than c-syntactic-end-of-macro to find the
upper boundary to "neutralize" syntactically obtrusive characters.
(c-change-expand-fl-region): Don't set c-new-END to next BOL when already at
one.

3 files changed, 85 insertions, 75 deletions

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index b9f25eeaee4..4d6a1203c25 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -229,8 +229,12 @@
 ;; The starting position from where we determined `c-macro-cache'.
 (defvar c-macro-cache-syntactic nil)
 (make-variable-buffer-local 'c-macro-cache-syntactic)
-;; non-nil iff `c-macro-cache' has both elements set AND the cdr is at a
-;; syntactic end of macro, not merely an apparent one.
+;; Either nil, or the syntactic end of the macro currently represented by
+;; `c-macro-cache'.
+(defvar c-macro-cache-no-comment nil)
+(make-variable-buffer-local 'c-macro-cache-no-comment)
+;; Either nil, or the last character of the macro currently represented by
+;; `c-macro-cache' which isn't in a comment. */
 
 (defun c-invalidate-macro-cache (beg end)
   ;; Called from a before-change function.  If the change region is before or
@@ -242,12 +246,14 @@
    ((< beg (car c-macro-cache))
     (setq c-macro-cache nil
           c-macro-cache-start-pos nil
-          c-macro-cache-syntactic nil))
+          c-macro-cache-syntactic nil
+          c-macro-cache-no-comment nil))
    ((and (cdr c-macro-cache)
          (< beg (cdr c-macro-cache)))
     (setcdr c-macro-cache nil)
     (setq c-macro-cache-start-pos beg
-          c-macro-cache-syntactic nil))))
+          c-macro-cache-syntactic nil
+          c-macro-cache-no-comment nil))))
 
 (defun c-macro-is-genuine-p ()
   ;; Check that the ostensible CPP construct at point is a real one.  In
@@ -288,7 +294,8 @@ comment at the start of cc-engine.el for more info."
                    t))
         (setq c-macro-cache nil
               c-macro-cache-start-pos nil
-              c-macro-cache-syntactic nil)
+              c-macro-cache-syntactic nil
+              c-macro-cache-no-comment nil)
 
         (save-restriction
           (if lim (narrow-to-region lim (point-max)))
@@ -323,7 +330,8 @@ comment at the start of cc-engine.el for more info."
                   (>= (point) (car c-macro-cache)))
        (setq c-macro-cache nil
              c-macro-cache-start-pos nil
-             c-macro-cache-syntactic nil))
+             c-macro-cache-syntactic nil
+             c-macro-cache-no-comment nil))
      (while (progn
               (end-of-line)
               (when (and (eq (char-before) ?\\)
@@ -347,14 +355,38 @@ comment at the start of cc-engine.el for more info."
   (let* ((here (point))
          (there (progn (c-end-of-macro) (point)))
          s)
-    (unless c-macro-cache-syntactic
+    (if c-macro-cache-syntactic
+        (goto-char c-macro-cache-syntactic)
       (setq s (parse-partial-sexp here there))
       (while (and (or (nth 3 s)  ; in a string
                       (nth 4 s)) ; in a comment (maybe at end of line comment)
                   (> there here))       ; No infinite loops, please.
         (setq there (1- (nth 8 s)))
         (setq s (parse-partial-sexp here there)))
-      (setq c-macro-cache-syntactic (car c-macro-cache)))
+      (setq c-macro-cache-syntactic (point)))
+    (point)))
+
+(defun c-no-comment-end-of-macro ()
+  ;; Go to the end of a CPP directive, or a pos just before which isn't in a
+  ;; comment.  For this purpose, open strings are ignored.
+  ;;
+  ;; This function must only be called from the beginning of a CPP construct.
+  ;;
+  ;; Note that this function might do hidden buffer changes.  See the comment
+  ;; at the start of cc-engine.el for more info.
+  (let* ((here (point))
+         (there (progn (c-end-of-macro) (point)))
+         s)
+    (if c-macro-cache-no-comment
+        (goto-char c-macro-cache-no-comment)
+      (setq s (parse-partial-sexp here there))
+      (while (and (nth 3 s)      ; in a string
+                  (> there here))       ; No infinite loops, please.
+        (setq here (1+ (nth 8 s)))
+        (setq s (parse-partial-sexp here there)))
+      (when (nth 4 s)
+        (goto-char (1- (nth 8 s))))
+      (setq c-macro-cache-no-comment (point)))
     (point)))
 
 (defun c-forward-over-cpp-define-id ()
diff --git a/lisp/progmodes/cc-langs.el b/lisp/progmodes/cc-langs.el
index 10fed6d77fc..6f4d1f16857 100644
--- a/lisp/progmodes/cc-langs.el
+++ b/lisp/progmodes/cc-langs.el
@@ -476,7 +476,8 @@ so that all identifiers are recognized as words.")
   c++ '(c-extend-region-for-CPP
         c-before-change-check-<>-operators
         c-invalidate-macro-cache)
-  (c objc) '(c-extend-region-for-CPP c-invalidate-macro-cache)
+  (c objc) '(c-extend-region-for-CPP
+             c-invalidate-macro-cache)
   ;; java 'c-before-change-check-<>-operators
   awk 'c-awk-record-region-clear-NL)
 (c-lang-defvar c-get-state-before-change-functions
@@ -505,9 +506,11 @@ parameters \(point-min) and \(point-max).")
   ;; For documentation see the following c-lang-defvar of the same name.
   ;; The value here may be a list of functions or a single function.
   t 'c-change-expand-fl-region
-  (c objc) '(c-neutralize-syntax-in-and-mark-CPP
+  (c objc) '(c-extend-font-lock-region-for-macros
+             c-neutralize-syntax-in-and-mark-CPP
              c-change-expand-fl-region)
-  c++ '(c-neutralize-syntax-in-and-mark-CPP
+  c++ '(c-extend-font-lock-region-for-macros
+        c-neutralize-syntax-in-and-mark-CPP
         c-restore-<>-properties
         c-change-expand-fl-region)
   java '(c-restore-<>-properties
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index de903b80ade..9ab04808af6 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -865,14 +865,6 @@ Note that the style variables are always made local to the buffer."
 
 ;;; Change hooks, linking with Font Lock and electric-indent-mode.
 
-;; Buffer local variables recording Beginning/End-of-Macro position before a
-;; change, when a macro straddles, respectively, the BEG or END (or both) of
-;; the change region.  Otherwise these have the values BEG/END.
-(defvar c-old-BOM 0)
-(make-variable-buffer-local 'c-old-BOM)
-(defvar c-old-EOM 0)
-(make-variable-buffer-local 'c-old-EOM)
-
 (defun c-called-from-text-property-change-p ()
   ;; Is the primitive which invoked `before-change-functions' or
   ;; `after-change-functions' one which merely changes text properties?  This
@@ -886,8 +878,8 @@ Note that the style variables are always made local to the buffer."
         '(put-text-property remove-list-of-text-properties)))
 
 (defun c-extend-region-for-CPP (beg end)
-  ;; Set c-old-BOM or c-old-EOM respectively to BEG, END, each extended to the
-  ;; beginning/end of any preprocessor construct they may be in.
+  ;; Adjust `c-new-BEG', `c-new-END' respectively to the beginning and end of
+  ;; any preprocessor construct they may be in. 
   ;;
   ;; Point is undefined both before and after this function call; the buffer
   ;; has already been widened, and match-data saved.  The return value is
@@ -896,45 +888,33 @@ Note that the style variables are always made local to the buffer."
   ;; This function is in the C/C++/ObjC values of
   ;; `c-get-state-before-change-functions' and is called exclusively as a
   ;; before change function.
-  (goto-char beg)
+  (goto-char c-new-BEG)
   (c-beginning-of-macro)
-  (setq c-old-BOM (point))
+  (setq c-new-BEG (point))
 
-  (goto-char end)
+  (goto-char c-new-END)
   (when (c-beginning-of-macro)
     (c-end-of-macro)
     (or (eobp) (forward-char)))  ; Over the terminating NL which may be marked
                                  ; with a c-cpp-delimiter category property
-  (setq c-old-EOM (point)))
-
-(defun c-extend-font-lock-region-for-macros (begg endd &optional old-len)
-  ;; Extend the region (BEGG ENDD) to cover all (possibly changed)
-  ;; preprocessor macros; return the cons (new-BEG . new-END).  OLD-LEN should
-  ;; be either the old length parameter when called from an
-  ;; after-change-function, or nil otherwise.  This defun uses the variables
-  ;; c-old-BOM, c-new-BOM.
+  (setq c-new-END (point)))
+
+(defun c-extend-font-lock-region-for-macros (begg endd old-len)
+  ;; Extend the region (c-new-BEG c-new-END) to cover all (possibly changed)
+  ;; preprocessor macros; The return value has no significance.
   ;;
   ;; Point is undefined on both entry and exit to this function.  The buffer
   ;; will have been widened on entry.
-  (let (limits new-beg new-end)
-    (goto-char c-old-BOM)         ; already set to old start of macro or begg.
-    (setq new-beg
-          (min begg
-               (if (setq limits (c-state-literal-at (point)))
-                   (cdr limits)     ; go forward out of any string or comment.
-                 (point))))
-
-    (goto-char endd)
-    (if (setq limits (c-state-literal-at (point)))
-        (goto-char (car limits)))  ; go backward out of any string or comment.
-    (if (c-beginning-of-macro)
-        (c-end-of-macro))
-    (setq new-end (max endd
-                       (if old-len
-                           (+ (- c-old-EOM old-len) (- endd begg))
-                         c-old-EOM)
-                       (point)))
-    (cons new-beg new-end)))
+  ;;
+  ;; This function is in the C/C++/ObjC value of `c-before-font-lock-functions'.
+  (goto-char endd)
+  (if (c-beginning-of-macro)
+      (c-end-of-macro))
+  (setq c-new-END (max endd c-new-END (point)))
+  ;; Determine the region, (c-new-BEG c-new-END), which will get font
+  ;; locked.  This restricts the region should there be long macros.
+  (setq c-new-BEG (max c-new-BEG (c-determine-limit 500 begg))
+        c-new-END (min c-new-END (c-determine-+ve-limit 500 endd))))
 
 (defun c-neutralize-CPP-line (beg end)
   ;; BEG and END bound a region, typically a preprocessor line.  Put a
@@ -963,19 +943,14 @@ Note that the style variables are always made local to the buffer."
              (t nil)))))))
 
 (defun c-neutralize-syntax-in-and-mark-CPP (begg endd old-len)
-  ;; (i) Extend the font lock region to cover all changed preprocessor
-  ;; regions; it does this by setting the variables `c-new-BEG' and
-  ;; `c-new-END' to the new boundaries.
-  ;;
-  ;; (ii) "Neutralize" every preprocessor line wholly or partially in the
-  ;; extended changed region.  "Restore" lines which were CPP lines before the
-  ;; change and are no longer so; these can be located from the Buffer local
-  ;; variables `c-old-BOM' and `c-old-EOM'.
+  ;; (i) "Neutralize" every preprocessor line wholly or partially in the
+  ;; changed region.  "Restore" lines which were CPP lines before the change
+  ;; and are no longer so.
   ;;
-  ;; (iii) Mark every CPP construct by placing a `category' property value
+  ;; (ii) Mark each CPP construct by placing a `category' property value
   ;; `c-cpp-delimiter' at its start and end.  The marked characters are the
   ;; opening # and usually the terminating EOL, but sometimes the character
-  ;; before a comment/string delimiter.
+  ;; before a comment delimiter.
   ;;
   ;; That is, set syntax-table properties on characters that would otherwise
   ;; interact syntactically with those outside the CPP line(s).
@@ -992,15 +967,8 @@ Note that the style variables are always made local to the buffer."
   ;; Note: SPEED _MATTERS_ IN THIS FUNCTION!!!
   ;;
   ;; This function might make hidden buffer changes.
-  (c-save-buffer-state (new-bounds)
-    ;; First determine the region, (c-new-BEG c-new-END), which will get font
-    ;; locked.  It might need "neutralizing".  This region may not start
-    ;; inside a string, comment, or macro.
-    (setq new-bounds (c-extend-font-lock-region-for-macros
-                      c-new-BEG c-new-END old-len))
-    (setq c-new-BEG (max (car new-bounds) (c-determine-limit 500 begg))
-          c-new-END (min (cdr new-bounds) (c-determine-+ve-limit 500 endd)))
-    ;; Clear all old relevant properties.
+  (c-save-buffer-state (limits )
+    ;; Clear 'syntax-table properties "punctuation":
     (c-clear-char-property-with-value c-new-BEG c-new-END 'syntax-table '(1))
 
     ;; CPP "comment" markers:
@@ -1011,6 +979,8 @@ Note that the style variables are always made local to the buffer."
 
     ;; Add needed properties to each CPP construct in the region.
     (goto-char c-new-BEG)
+    (if (setq limits (c-literal-limits)) ; Go past any literal.
+        (goto-char (cdr limits)))
     (skip-chars-backward " \t")
     (let ((pps-position (point))  pps-state mbeg)
       (while (and (< (point) c-new-END)
@@ -1030,7 +1000,7 @@ Note that the style variables are always made local to the buffer."
                       (nth 4 pps-state)))) ; in a comment?
           (goto-char (match-beginning 1))
           (setq mbeg (point))
-          (if (> (c-syntactic-end-of-macro) mbeg)
+          (if (> (c-no-comment-end-of-macro) mbeg)
               (progn
                 (c-neutralize-CPP-line mbeg (point)) ; "punctuation" properties
                 (if (eval-when-compile
@@ -1256,10 +1226,15 @@ Note that the style variables are always made local to the buffer."
   ;;
   ;; This is called from an after-change-function, but the parameters BEG END
   ;; and OLD-LEN are not used.
-   (if font-lock-mode
-       (setq c-new-BEG
-             (or (c-fl-decl-start c-new-BEG) (c-point 'bol c-new-BEG))
-             c-new-END (c-point 'bonl c-new-END))))
+  (if font-lock-mode
+      (setq c-new-BEG
+            (or (c-fl-decl-start c-new-BEG) (c-point 'bol c-new-BEG))
+            c-new-END
+            (save-excursion
+              (goto-char c-new-END)
+              (if (bolp)
+                  (point)
+                (c-point 'bonl c-new-END))))))
 
 (defun c-context-expand-fl-region (beg end)
   ;; Return a cons (NEW-BEG . NEW-END), where NEW-BEG is the beginning of a