1 files changed, 25 insertions, 52 deletions

diff --git a/src/data.c b/src/data.c
index d2f4d40d7bc..9d7e7effdcd 100644
--- a/src/data.c
+++ b/src/data.c
@@ -683,7 +683,7 @@ global value outside of any lexical scope.  */)
   switch (sym->u.s.redirect)
     {
     case SYMBOL_PLAINVAL: valcontents = SYMBOL_VAL (sym); break;
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_LOCALIZED:
       {
         struct Lisp_Buffer_Local_Value *blv = SYMBOL_BLV (sym);
@@ -773,7 +773,10 @@ DEFUN ("symbol-plist", Fsymbol_plist, Ssymbol_plist, 1, 1, 0,
 }
 
 DEFUN ("symbol-name", Fsymbol_name, Ssymbol_name, 1, 1, 0,
-       doc: /* Return SYMBOL's name, a string.  */)
+       doc: /* Return SYMBOL's name, a string.
+
+Warning: never alter the string returned by `symbol-name'.
+Doing that might make Emacs dysfunctional, and might even crash Emacs.  */)
   (register Lisp_Object symbol)
 {
   register Lisp_Object name;
@@ -1246,51 +1249,20 @@ The value, if non-nil, is a list of mode name symbols.  */)
                 Getting and Setting Values of Symbols
  ***********************************************************************/
 
-/* Return the symbol holding SYMBOL's value.  Signal
-   `cyclic-variable-indirection' if SYMBOL's chain of variable
-   indirections contains a loop.  */
-
-struct Lisp_Symbol *
-indirect_variable (struct Lisp_Symbol *symbol)
-{
-  struct Lisp_Symbol *tortoise, *hare;
-
-  hare = tortoise = symbol;
-
-  while (hare->u.s.redirect == SYMBOL_VARALIAS)
-    {
-      hare = SYMBOL_ALIAS (hare);
-      if (hare->u.s.redirect != SYMBOL_VARALIAS)
-        break;
-
-      hare = SYMBOL_ALIAS (hare);
-      tortoise = SYMBOL_ALIAS (tortoise);
-
-      if (hare == tortoise)
-        {
-          Lisp_Object tem;
-          XSETSYMBOL (tem, symbol);
-          xsignal1 (Qcyclic_variable_indirection, tem);
-        }
-    }
-
-  return hare;
-}
-
-
 DEFUN ("indirect-variable", Findirect_variable, Sindirect_variable, 1, 1, 0,
        doc: /* Return the variable at the end of OBJECT's variable chain.
 If OBJECT is a symbol, follow its variable indirections (if any), and
 return the variable at the end of the chain of aliases.  See Info node
 `(elisp)Variable Aliases'.
 
-If OBJECT is not a symbol, just return it.  If there is a loop in the
-chain of aliases, signal a `cyclic-variable-indirection' error.  */)
+If OBJECT is not a symbol, just return it.  */)
   (Lisp_Object object)
 {
   if (SYMBOLP (object))
     {
-      struct Lisp_Symbol *sym = indirect_variable (XSYMBOL (object));
+      struct Lisp_Symbol *sym = XSYMBOL (object);
+      while (sym->u.s.redirect == SYMBOL_VARALIAS)
+        sym = SYMBOL_ALIAS (sym);
       XSETSYMBOL (object, sym);
     }
   return object;
@@ -1579,7 +1551,7 @@ find_symbol_value (Lisp_Object symbol)
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: return SYMBOL_VAL (sym);
     case SYMBOL_LOCALIZED:
       {
@@ -1668,7 +1640,7 @@ set_internal (Lisp_Object symbol, Lisp_Object newval, Lisp_Object where,
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: SET_SYMBOL_VAL (sym , newval); return;
     case SYMBOL_LOCALIZED:
       {
@@ -1922,7 +1894,7 @@ default_value (Lisp_Object symbol)
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: return SYMBOL_VAL (sym);
     case SYMBOL_LOCALIZED:
       {
@@ -2016,7 +1988,7 @@ set_default_internal (Lisp_Object symbol, Lisp_Object value,
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: set_internal (symbol, value, Qnil, bindflag); return;
     case SYMBOL_LOCALIZED:
       {
@@ -2154,7 +2126,7 @@ See also `defvar-local'.  */)
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL:
       forwarded = 0; valcontents.value = SYMBOL_VAL (sym);
       if (BASE_EQ (valcontents.value, Qunbound))
@@ -2222,7 +2194,7 @@ Instead, use `add-hook' and specify t for the LOCAL argument.  */)
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL:
       forwarded = 0; valcontents.value = SYMBOL_VAL (sym); break;
     case SYMBOL_LOCALIZED:
@@ -2308,7 +2280,7 @@ From now on the default value will apply in this buffer.  Return VARIABLE.  */)
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: return variable;
     case SYMBOL_FORWARDED:
       {
@@ -2375,7 +2347,7 @@ Also see `buffer-local-boundp'.*/)
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: return Qnil;
     case SYMBOL_LOCALIZED:
       {
@@ -2425,7 +2397,7 @@ value in BUFFER, or if VARIABLE is automatically buffer-local (see
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: return Qnil;
     case SYMBOL_LOCALIZED:
       {
@@ -2460,7 +2432,7 @@ If the current binding is global (the default), the value is nil.  */)
  start:
   switch (sym->u.s.redirect)
     {
-    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
+    case SYMBOL_VARALIAS: sym = SYMBOL_ALIAS (sym); goto start;
     case SYMBOL_PLAINVAL: return Qnil;
     case SYMBOL_FORWARDED:
       {
@@ -3218,9 +3190,9 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args,
         intmax_t a;
         switch (code)
           {
-          case Aadd : overflow = INT_ADD_WRAPV (accum, next, &a); break;
-          case Amult: overflow = INT_MULTIPLY_WRAPV (accum, next, &a); break;
-          case Asub : overflow = INT_SUBTRACT_WRAPV (accum, next, &a); break;
+          case Aadd : overflow = ckd_add (&a, accum, next); break;
+          case Amult: overflow = ckd_mul (&a, accum, next); break;
+          case Asub : overflow = ckd_sub (&a, accum, next); break;
           case Adiv:
             if (next == 0)
               xsignal0 (Qarith_error);
@@ -4214,10 +4186,11 @@ syms_of_data (void)
   Fput (Qrecursion_error, Qerror_message, build_pure_c_string
         ("Excessive recursive calling error"));
 
-  PUT_ERROR (Qexcessive_variable_binding, recursion_tail,
-             "Variable binding depth exceeds max-specpdl-size");
   PUT_ERROR (Qexcessive_lisp_nesting, recursion_tail,
              "Lisp nesting exceeds `max-lisp-eval-depth'");
+  /* Error obsolete (from 29.1), kept for compatibility.  */
+  PUT_ERROR (Qexcessive_variable_binding, recursion_tail,
+             "Variable binding depth exceeds max-specpdl-size");
 
   /* Types that type-of returns.  */
   DEFSYM (Qinteger, "integer");