CC Mode. Create lang vars for certain skipping expressions at compile time

This saves repeated calculations at run time.

* lisp/progmodes/cc-langs.el (c-stmt-boundary-skip-chars)
(c-stmt-boundary-skip-list, c-stmt-boundary-skip-chars-with-comma)
(c-stmt-boundary-skip-list-with-comma): New lang constants/variables.

* lisp/progmodes/cc-engine.el (c-commas-bound-stmts): New variable
(c-beginning-of-statement-1): Set c-commas-bound-stmts rather than
c-stmt-delim-chars.
(c-crosses-statement-barrier-p): Remove the now unneeded calculations of
c-stmt-delim-chars.  Set skip chars to one of the new lang variables, and
later to a substring of it.
(c-at-statement-start-p): Set c-syntactic-skip-backward from the new
variables.
(c-at-expression-start-p): Bind c-commas-bound-stmts.  Use
c-stmt-delim-chars-with-comma rather than c-stmt-delim-chars in a backward
scan.
(c-guess-basic-syntax): Bind c-commas-bound-stmts rather than
c-stmt-delim-chars to itself.  Bind c-commas-bound-stmts to t at another place
rather than setting c-stmt-delim-chars to c-stmt-delim-chars-with-comma.

2 files changed, 72 insertions, 24 deletions

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index a89528d033c..1ebacb58c7f 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -713,6 +713,10 @@ comment at the start of cc-engine.el for more info."
 ;; the byte compiler.
 (defvar c-maybe-labelp)
 
+(defvar c-commas-bound-stmts nil)
+  ;; Set to non-nil when `c-beginning-of-statement-1' is to regard a comma as
+  ;; a statement terminator.
+
 ;; New awk-compatible version of c-beginning-of-statement-1, ACM 2002/6/22
 
 ;; Macros used internally in c-beginning-of-statement-1 for the
@@ -897,9 +901,7 @@ comment at the start of cc-engine.el for more info."
         (start (point))
         macro-start
         (delims (if comma-delim '(?\; ?,) '(?\;)))
-        (c-stmt-delim-chars (if comma-delim
-                                c-stmt-delim-chars-with-comma
-                              c-stmt-delim-chars))
+        (c-commas-bound-stmts (or c-commas-bound-stmts comma-delim))
         c-maybe-labelp after-case:-pos saved
         ;; Current position.
         pos
@@ -1422,21 +1424,12 @@ the line.  If this virtual semicolon is _at_ from, the function recognizes it.
 
 Note that this function might do hidden buffer changes.  See the
 comment at the start of cc-engine.el for more info."
-  (let* ((skip-chars
-          ;; If the current language has CPP macros, insert # into skip-chars.
-          (if c-opt-cpp-symbol
-              (concat (substring c-stmt-delim-chars 0 1) ; "^"
-                      c-opt-cpp-symbol                   ; usually "#"
-                      (substring c-stmt-delim-chars 1))  ; e.g. ";{}?:"
-            c-stmt-delim-chars))
-         (skip-chars
-          (if (c-major-mode-is 'c++-mode)
-              (concat (substring skip-chars 0 1) ; "^"
-                      "["                        ; to catch C++ attributes
-                      (substring skip-chars 1)) ; e.g. "#;{}?:"
-            skip-chars))
-         (non-skip-list
-          (append (substring skip-chars 1) nil)) ; e.g. (?# ?\; ?{ ?} ?? ?:)
+  (let* ((skip-chars (if c-commas-bound-stmts
+                         c-stmt-boundary-skip-chars-with-comma
+                       c-stmt-boundary-skip-chars))   ; e.g. "^#;{}?:"
+         (non-skip-list (if c-commas-bound-stmts
+                            c-stmt-boundary-skip-list-with-comma
+                          c-stmt-boundary-skip-list)) ; e.g. (?# ?\; ?{ ?} ?? ?:)
          lit-range lit-start vsemi-pos attr-end)
     (save-restriction
       (widen)
@@ -1477,7 +1470,11 @@ comment at the start of cc-engine.el for more info."
               ;; A question mark.  Can't be a label, so stop
               ;; looking for more : and ?.
               (setq c-maybe-labelp nil
-                    skip-chars (substring c-stmt-delim-chars 0 -2)))
+                    skip-chars
+                    (substring (if c-commas-bound-stmts
+                                   c-stmt-delim-chars-with-comma
+                                 c-stmt-delim-chars)
+                               0 -2)))
              ;; At a CPP construct or a "#" or "##" operator?
              ((and c-opt-cpp-symbol (looking-at c-opt-cpp-symbol))
               (if (save-excursion
@@ -1513,7 +1510,13 @@ comment at the start of cc-engine.el for more info."
   (save-excursion
     (let ((end (point))
           c-maybe-labelp)
-      (c-syntactic-skip-backward (substring c-stmt-delim-chars 1) nil t)
+      (c-syntactic-skip-backward
+       (substring
+        (if c-commas-bound-stmts
+            c-stmt-delim-chars-with-comma
+          c-stmt-delim-chars)
+        1)
+       nil t)
       (or (bobp)
           (eq (char-before) ?})
           (and (eq (char-before) ?{)
@@ -1540,9 +1543,10 @@ comment at the start of cc-engine.el for more info."
 
   (save-excursion
     (let ((end (point))
-          (c-stmt-delim-chars c-stmt-delim-chars-with-comma)
+          (c-commas-bound-stmts t)
           c-maybe-labelp)
-      (c-syntactic-skip-backward (substring c-stmt-delim-chars 1) nil t)
+      (c-syntactic-skip-backward (substring c-stmt-delim-chars-with-comma 1)
+                                 nil t)
       (or (bobp)
           (memq (char-before) '(?{ ?}))
           (save-excursion (backward-char)
@@ -12587,7 +12591,7 @@ comment at the start of cc-engine.el for more info."
          ;; There's always at most one syntactic element which got
          ;; an anchor pos.  It's stored in syntactic-relpos.
          syntactic-relpos
-         (c-stmt-delim-chars c-stmt-delim-chars))
+         (c-commas-bound-stmts c-commas-bound-stmts))
 
       ;; Check if we're directly inside an enclosing declaration
       ;; level block.
@@ -12639,7 +12643,7 @@ comment at the start of cc-engine.el for more info."
       ;; arglists.
       (when (and containing-sexp
                  (eq (char-after containing-sexp) ?\())
-        (setq c-stmt-delim-chars c-stmt-delim-chars-with-comma))
+        (setq c-commas-bound-stmts t))
       ;; cache char before and after indent point, and move point to
       ;; the most likely position to perform the majority of tests
       (goto-char indent-point)
diff --git a/lisp/progmodes/cc-langs.el b/lisp/progmodes/cc-langs.el
index a0d4559c207..8a4f8f59515 100644
--- a/lisp/progmodes/cc-langs.el
+++ b/lisp/progmodes/cc-langs.el
@@ -1442,12 +1442,56 @@ operators."
   t "^;{}?:")
 (c-lang-defvar c-stmt-delim-chars (c-lang-const c-stmt-delim-chars))
 
+(c-lang-defconst c-stmt-boundary-skip-chars
+  ;; Like `c-stmt-delim-chars', but augmented by "#" for languages with CPP
+  ;; constructs, and for C++ Mode, also by "[", to help deal with C++
+  ;; attributes.
+  t (if (c-lang-const c-opt-cpp-symbol)
+        (concat (substring (c-lang-const c-stmt-delim-chars) 0 1) ; "^"
+                (c-lang-const c-opt-cpp-symbol) ; usually #
+                (substring (c-lang-const c-stmt-delim-chars) 1)) ; ";{}?:"
+      (c-lang-const c-stmt-delim-chars))
+  c++ (concat (substring (c-lang-const c-stmt-boundary-skip-chars) 0 1) ; "^"
+              "["
+              (substring (c-lang-const c-stmt-boundary-skip-chars) 1))) ; ";{}?:"
+(c-lang-defvar c-stmt-boundary-skip-chars
+  (c-lang-const c-stmt-boundary-skip-chars))
+
+(c-lang-defconst c-stmt-boundary-skip-list
+  ;; The characters (apart from the initial ^) in `c-stmt-boundary-skip-chars'
+  ;; as a list of characters.
+  t (append (substring (c-lang-const c-stmt-boundary-skip-chars) 1) nil))
+(c-lang-defvar c-stmt-boundary-skip-list
+  (c-lang-const c-stmt-boundary-skip-list))
+
 (c-lang-defconst c-stmt-delim-chars-with-comma
   ;; Variant of `c-stmt-delim-chars' that additionally contains ','.
   t    "^;,{}?:")
 (c-lang-defvar c-stmt-delim-chars-with-comma
   (c-lang-const c-stmt-delim-chars-with-comma))
 
+(c-lang-defconst c-stmt-boundary-skip-chars-with-comma
+  ;; Variant of `c-stmt-boundary-skip-chars' also containing ','.
+  t (if (c-lang-const c-opt-cpp-symbol)
+        (concat (substring (c-lang-const c-stmt-delim-chars-with-comma) 0 1)
+                (c-lang-const c-opt-cpp-symbol) ; usually #
+                (substring (c-lang-const c-stmt-delim-chars-with-comma) 1))
+      (c-lang-const c-stmt-delim-chars-with-comma))
+  c++ (concat
+       (substring (c-lang-const c-stmt-boundary-skip-chars-with-comma) 0 1) ; "^"
+       "["
+       (substring (c-lang-const c-stmt-boundary-skip-chars-with-comma) 1))) ; ";,{}?:"
+(c-lang-defvar c-stmt-boundary-skip-chars-with-comma
+  (c-lang-const c-stmt-boundary-skip-chars-with-comma))
+
+(c-lang-defconst c-stmt-boundary-skip-list-with-comma
+  ;; Variant of `c-stmt-boundary-skip-list' also including a comma.
+  t (append (substring (c-lang-const c-stmt-boundary-skip-chars-with-comma)
+                       1)
+            nil))
+(c-lang-defvar c-stmt-boundary-skip-list-with-comma
+  (c-lang-const c-stmt-boundary-skip-list-with-comma))
+
 (c-lang-defconst c-pack-ops
   "Ops which signal C++11's \"parameter pack\""
   t nil