Make struct Lisp_Objfwd etc. objects read-only

Initialize these objects statically, and make them constants.
This is a bit safer and more efficient.
* src/data.c (XBOOLFWD, XKBOARD_OBJFWD, XFIXNUMFWD, XOBJFWD):
* src/lisp.h (XBUFFER_OBJFWD):
Return a pointer-to-const instead of an unrestricted pointer.
(lispfwd): fwdptr is now a pointer-to-const instead of an
unrestricted pointer.  All uses changed.
(SET_SYMBOL_FWD): Accept pointer-to-const instead of an
unrestricted pointer.
(DEFVAR_LISP, DEFVAR_LISP_NOPRO, DEFVAR_BOOL, DEFVAR_INT)
(DEFVAR_KBOARD): Initialize static structures statically
instead of dynamically, and make them const.
* src/lread.c (defvar_int, defvar_bool, defvar_lisp_nopro)
(defvar_lisp, defvar_kboard): Accept pointer-to-const instead
of an unrestricted pointer; it’s now the caller’s
responsibility to initialize the pointed-to storage.  No need
for a separate address argument any more.  All callers
changed.

1 files changed, 12 insertions, 30 deletions

diff --git a/src/lread.c b/src/lread.c
index dd35cf9063e..5f33fcd6957 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -4425,28 +4425,19 @@ defalias (struct Lisp_Subr *sname, char *string)
    C variable of type intmax_t.  Sample call (with "xx" to fool make-docfile):
    DEFxxVAR_INT ("emacs-priority", &emacs_priority, "Documentation");  */
 void
-defvar_int (struct Lisp_Intfwd *i_fwd,
-            const char *namestring, intmax_t *address)
+defvar_int (struct Lisp_Intfwd const *i_fwd, char const *namestring)
 {
-  Lisp_Object sym;
-  sym = intern_c_string (namestring);
-  i_fwd->type = Lisp_Fwd_Int;
-  i_fwd->intvar = address;
+  Lisp_Object sym = intern_c_string (namestring);
   XSYMBOL (sym)->u.s.declared_special = true;
   XSYMBOL (sym)->u.s.redirect = SYMBOL_FORWARDED;
   SET_SYMBOL_FWD (XSYMBOL (sym), i_fwd);
 }
 
-/* Similar but define a variable whose value is t if address contains 1,
-   nil if address contains 0.  */
+/* Similar but define a variable whose value is t if 1, nil if 0.  */
 void
-defvar_bool (struct Lisp_Boolfwd *b_fwd,
-             const char *namestring, bool *address)
+defvar_bool (struct Lisp_Boolfwd const *b_fwd, char const *namestring)
 {
-  Lisp_Object sym;
-  sym = intern_c_string (namestring);
-  b_fwd->type = Lisp_Fwd_Bool;
-  b_fwd->boolvar = address;
+  Lisp_Object sym = intern_c_string (namestring);
   XSYMBOL (sym)->u.s.declared_special = true;
   XSYMBOL (sym)->u.s.redirect = SYMBOL_FORWARDED;
   SET_SYMBOL_FWD (XSYMBOL (sym), b_fwd);
@@ -4459,37 +4450,28 @@ defvar_bool (struct Lisp_Boolfwd *b_fwd,
    gc-marked for some other reason, since marking the same slot twice
    can cause trouble with strings.  */
 void
-defvar_lisp_nopro (struct Lisp_Objfwd *o_fwd,
-                   const char *namestring, Lisp_Object *address)
+defvar_lisp_nopro (struct Lisp_Objfwd const *o_fwd, char const *namestring)
 {
-  Lisp_Object sym;
-  sym = intern_c_string (namestring);
-  o_fwd->type = Lisp_Fwd_Obj;
-  o_fwd->objvar = address;
+  Lisp_Object sym = intern_c_string (namestring);
   XSYMBOL (sym)->u.s.declared_special = true;
   XSYMBOL (sym)->u.s.redirect = SYMBOL_FORWARDED;
   SET_SYMBOL_FWD (XSYMBOL (sym), o_fwd);
 }
 
 void
-defvar_lisp (struct Lisp_Objfwd *o_fwd,
-             const char *namestring, Lisp_Object *address)
+defvar_lisp (struct Lisp_Objfwd const *o_fwd, char const *namestring)
 {
-  defvar_lisp_nopro (o_fwd, namestring, address);
-  staticpro (address);
+  defvar_lisp_nopro (o_fwd, namestring);
+  staticpro (o_fwd->objvar);
 }
 
 /* Similar but define a variable whose value is the Lisp Object stored
    at a particular offset in the current kboard object.  */
 
 void
-defvar_kboard (struct Lisp_Kboard_Objfwd *ko_fwd,
-               const char *namestring, int offset)
+defvar_kboard (struct Lisp_Kboard_Objfwd const *ko_fwd, char const *namestring)
 {
-  Lisp_Object sym;
-  sym = intern_c_string (namestring);
-  ko_fwd->type = Lisp_Fwd_Kboard_Obj;
-  ko_fwd->offset = offset;
+  Lisp_Object sym = intern_c_string (namestring);
   XSYMBOL (sym)->u.s.declared_special = true;
   XSYMBOL (sym)->u.s.redirect = SYMBOL_FORWARDED;
   SET_SYMBOL_FWD (XSYMBOL (sym), ko_fwd);