(DONT_COPY_FLAG): Default this to 1.

(mark_object): Use the same XOR expression as elsewhere.
(gc_sweep): Don't touch DONT_COPY_FLAG here; this one is a real size field,
not a mangled pointer.

diff --git a/src/alloc.c b/src/alloc.c
index ccd5a847dad88e53581a2c93426bafc4fe56fe05..5776a2be9271076ce8f47ca7e897bfeb8e5c00c8 100644 (file)
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -107,10 +107,15 @@ Lisp_Object memory_signal_data;
 #define MAX_SAVE_STACK 16000
 #endif
 
-/* Define DONT_COPY_FLAG to be the bit in a small string that was placed
-   in the low bit of the size field when marking small strings.  */
+/* Define DONT_COPY_FLAG to be some bit which will always be zero in a
+   pointer to a Lisp_Object, when that pointer is viewed as an integer.
+   (On most machines, pointers are even, so we can use the low bit.
+   Word-addressible architectures may need to override this in the m-file.)
+   When linking references to small strings through the size field, we
+   use this slot to hold the bit that would otherwise be interpreted as
+   the GC mark bit.  */
 #ifndef DONT_COPY_FLAG
-#define DONT_COPY_FLAG PSEUDOVECTOR_FLAG
+#define DONT_COPY_FLAG 1
 #endif /* no DONT_COPY_FLAG  */
 
 /* Buffer in which we save a copy of the C stack at each GC.  */
@@ -1509,8 +1514,7 @@ mark_object (objptr)
          {
            /* A small string.  Put this reference
               into the chain of references to it.
-              The address OBJPTR is even, so if the address
-              includes MARKBIT, put it in the low bit
+              If the address includes MARKBIT, put that bit elsewhere
               when we store OBJPTR into the size field.  */
 
            if (XMARKBIT (*objptr))
@@ -1523,9 +1527,9 @@ mark_object (objptr)
 
            if ((EMACS_INT) objptr & DONT_COPY_FLAG)
              abort ();
-           ptr->size = (EMACS_INT) objptr & ~MARKBIT;
-           if ((EMACS_INT) objptr & MARKBIT)
-             ptr->size |= DONT_COPY_FLAG;
+           ptr->size = (EMACS_INT) objptr;
+           if (ptr->size & MARKBIT)
+             ptr->size ^= MARKBIT | DONT_COPY_FLAG;
          }
       }
       break;
@@ -2043,7 +2047,7 @@ gc_sweep ()
        if (s->size & ARRAY_MARK_FLAG)
          {
            ((struct Lisp_String *)(&sb->chars[0]))->size
-             &= ~ARRAY_MARK_FLAG & ~MARKBIT & ~DONT_COPY_FLAG;
+             &= ~ARRAY_MARK_FLAG & ~MARKBIT;
            UNMARK_BALANCE_INTERVALS (s->intervals);
            total_string_size += ((struct Lisp_String *)(&sb->chars[0]))->size;
            prev = sb, sb = sb->next;