Remove struct Lisp_Buffer_Objfwd

* src/lisp.h (struct Lisp_Buffer_Objfwd): Deleted.
(struct Lisp_Fwd): Add the fields bufoffset and bufpredicate.
Make the type a 1-byte bitfield so that the entire struct still
fits in two words.
(XBUFFER_OFFSET): Renamed from XBUFFER_OBJFWD.
* src/buffer.c (DEFVAR_PER_BUFFER, defvar_per_buffer)
(buffer_local_value): Update accordingly.
* src/data.c (do_symval_forwarding, store_symval_forwarding)
(set_internal, default_value, set_default_internal)
(Fmake_local_variable, Fkill_local_variable, Flocal_variable_): Use
XBUFFER_OFFSET.

1 files changed, 14 insertions, 15 deletions

diff --git a/src/buffer.c b/src/buffer.c
index 9abce241897..cc559ad0ad6 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1402,7 +1402,7 @@ buffer_local_value (Lisp_Object variable, Lisp_Object buffer)
       {
         lispfwd fwd = SYMBOL_FWD (sym);
         if (BUFFER_OBJFWDP (fwd))
-          result = per_buffer_value (buf, XBUFFER_OBJFWD (fwd)->offset);
+          result = per_buffer_value (buf, XBUFFER_OFFSET (fwd));
         else
           result = Fdefault_value (variable);
         break;
@@ -4982,32 +4982,31 @@ init_buffer (void)
 
 /* FIXME: use LISPSYM_INITIALLY instead of TAG_PTR_INITIALLY */
 #define DEFVAR_PER_BUFFER(lname, vname, predicate_, doc)                \
-do                                                                      \
-  {                                                                     \
-    const Lisp_Object sym = TAG_PTR_INITIALLY (                         \
-        Lisp_Symbol, (intptr_t)((i##predicate_) * sizeof *lispsym));    \
-    static const struct Lisp_Fwd bo_fwd = {                             \
-      .type = Lisp_Fwd_Buffer_Obj,                                      \
-      .u.bufobjfwd = { .offset = offsetof (struct buffer, vname##_),    \
-                       .predicate = sym },                              \
-    };                                                                  \
+  do {                                                                  \
+    const Lisp_Object sym                                               \
+      = TAG_PTR_INITIALLY (Lisp_Symbol, (intptr_t)((i##predicate_)      \
+                                                   * sizeof *lispsym)); \
+    static const struct Lisp_Fwd bo_fwd                                 \
+        = { .type = Lisp_Fwd_Buffer_Obj,                                \
+            .bufoffset = offsetof (struct buffer, vname##_),            \
+            .u.bufpredicate = sym };                                    \
+    static_assert (offsetof (struct buffer, vname##_)                   \
+                   < (1 << 8 * sizeof bo_fwd.bufoffset));               \
     defvar_per_buffer (&bo_fwd, lname);                                 \
-  }                                                                     \
-while (0)
+  } while (0)
 
 static void
 defvar_per_buffer (const struct Lisp_Fwd *fwd, const char *namestring)
 {
   eassert (fwd->type == Lisp_Fwd_Buffer_Obj);
-  const struct Lisp_Buffer_Objfwd *bo_fwd = XBUFFER_OBJFWD (fwd);
   struct Lisp_Symbol *sym = XSYMBOL (intern (namestring));
 
   sym->u.s.declared_special = true;
   sym->u.s.redirect = SYMBOL_FORWARDED;
   SET_SYMBOL_FWD (sym, fwd);
-  XSETSYMBOL (PER_BUFFER_SYMBOL (bo_fwd->offset), sym);
+  XSETSYMBOL (PER_BUFFER_SYMBOL (XBUFFER_OFFSET (fwd)), sym);
 
-  if (PER_BUFFER_IDX (bo_fwd->offset) == 0)
+  if (PER_BUFFER_IDX (XBUFFER_OFFSET (fwd)) == 0)
     /* Did a DEFVAR_PER_BUFFER without initializing the corresponding
        slot of buffer_local_flags.  */
     emacs_abort ();