Re: External inline functions

[Paul Eggert <eggert@cs.ucla.edu>]

Yes, that's right: pre-C99 'inline' is a portability minefield,
and GNU Emacs isn't portable even to C99's tricky semantics
for extern inline (among other things, extern inline functions
cannot call static functions).

I installed the following to work around the problems in this area that
I found.  But as this issue keeps coming up, how about if we
simply stop using extern inline functions?  They do not buy us
significant performance, and they are a hassle that is causing
portability problems, so this should be an easy call.

====

Fix some portability problems with 'inline'.
* dispextern.h (window_box, window_box_height, window_text_bottom_y)
(window_box_width, window_box_left, window_box_left_offset)
(window_box_right, window_box_right_offset): Declare extern.
Otherwise, these inline functions do not conform to C99 and
are miscompiled by Microsoft compilers.  Reported by Eli Zaretskii in
<http://lists.gnu.org/archive/html/emacs-devel/2011-11/msg00084.html>.
* intervals.c (adjust_intervals_for_insertion)
(adjust_intervals_for_deletion): Now extern, because otherwise the
extern inline functions 'offset_intervals' couldn't refer to it.
(static_offset_intervals): Remove.
(offset_intervals): Rewrite using the old contents of
static_offset_intervals.  The old version didn't conform to C99
because an extern inline function contained a reference to an
identifier with static linkage.
=== modified file 'src/dispextern.h'
--- src/dispextern.h	2011-10-25 16:36:20 +0000
+++ src/dispextern.h	2011-11-06 21:03:15 +0000
@@ -3006,14 +3006,14 @@
 void set_vertical_scroll_bar (struct window *);
 #endif
 int try_window (Lisp_Object, struct text_pos, int);
-void window_box (struct window *, int, int *, int *, int *, int *);
-int window_box_height (struct window *);
-int window_text_bottom_y (struct window *);
-int window_box_width (struct window *, int);
-int window_box_left (struct window *, int);
-int window_box_left_offset (struct window *, int);
-int window_box_right (struct window *, int);
-int window_box_right_offset (struct window *, int);
+extern void window_box (struct window *, int, int *, int *, int *, int *);
+extern int window_box_height (struct window *);
+extern int window_text_bottom_y (struct window *);
+extern int window_box_width (struct window *, int);
+extern int window_box_left (struct window *, int);
+extern int window_box_left_offset (struct window *, int);
+extern int window_box_right (struct window *, int);
+extern int window_box_right_offset (struct window *, int);
 int estimate_mode_line_height (struct frame *, enum face_id);
 void pixel_to_glyph_coords (struct frame *, int, int, int *, int *,
                             NativeRectangle *, int);

=== modified file 'src/intervals.c'
--- src/intervals.c	2011-10-26 01:18:13 +0000
+++ src/intervals.c	2011-11-06 21:03:14 +0000
@@ -52,6 +52,11 @@

 #define TMEM(sym, set) (CONSP (set) ? ! NILP (Fmemq (sym, set)) : ! NILP (set))

+extern INTERVAL adjust_intervals_for_insertion (INTERVAL,
+						EMACS_INT, EMACS_INT);
+extern void adjust_intervals_for_deletion (struct buffer *,
+					   EMACS_INT, EMACS_INT);
+
 static Lisp_Object merge_properties_sticky (Lisp_Object, Lisp_Object);
 static INTERVAL merge_interval_right (INTERVAL);
 static INTERVAL reproduce_tree (INTERVAL, INTERVAL);
@@ -798,7 +803,7 @@
    and check the hungry bits of both.  Then add the length going back up
    to the root.  */

-static INTERVAL
+INTERVAL
 adjust_intervals_for_insertion (INTERVAL tree, EMACS_INT position,
 				EMACS_INT length)
 {
@@ -859,7 +864,7 @@
    interval.  Another possibility would be to create a new interval for
    this text, and make it have the merged properties of both ends.  */

-static INTERVAL
+INTERVAL
 adjust_intervals_for_insertion (INTERVAL tree,
 				EMACS_INT position, EMACS_INT length)
 {
@@ -1369,7 +1374,7 @@
    text.  The deletion is effected at position START (which is a
    buffer position, i.e. origin 1).  */

-static void
+void
 adjust_intervals_for_deletion (struct buffer *buffer,
 			       EMACS_INT start, EMACS_INT length)
 {
@@ -1425,9 +1430,8 @@
    compiler that does not allow calling a static function (here,
    adjust_intervals_for_deletion) from a non-static inline function.  */

-static inline void
-static_offset_intervals (struct buffer *buffer, EMACS_INT start,
-			 EMACS_INT length)
+inline void
+offset_intervals (struct buffer *buffer, EMACS_INT start, EMACS_INT length)
 {
   if (NULL_INTERVAL_P (BUF_INTERVALS (buffer)) || length == 0)
     return;
@@ -1440,12 +1444,6 @@
       adjust_intervals_for_deletion (buffer, start, -length);
     }
 }
-
-inline void
-offset_intervals (struct buffer *buffer, EMACS_INT start, EMACS_INT length)
-{
-  static_offset_intervals (buffer, start, length);
-}
 \f
 /* Merge interval I with its lexicographic successor. The resulting
    interval is returned, and has the properties of the original