(DONT_COPY_FLAG): New bit flag.

(mark_object, gc_sweep, compact_strings): Use it.

1 files changed, 18 insertions, 8 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 044356914e5..64b7a11e3f2 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -107,6 +107,12 @@ 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.  */
+#ifndef DONT_COPY_FLAG
+#define DONT_COPY_FLAG PSEUDO_VECTOR_FLAG
+#endif /* no DONT_COPY_FLAG  */
+
 /* Buffer in which we save a copy of the C stack at each GC.  */
 
 char *stack_copy;
@@ -1514,10 +1520,12 @@ mark_object (objptr)
               }
             else
               XSETFASTINT (*objptr, ptr->size);
-            if ((EMACS_INT) objptr & 1) abort ();
+
+            if ((EMACS_INT) objptr & DONT_COPY_FLAG)
+              abort ();
             ptr->size = (EMACS_INT) objptr & ~MARKBIT;
             if ((EMACS_INT) objptr & MARKBIT)
-              ptr->size ++;
+              ptr->size |= DONT_COPY_FLAG;
           }
       }
       break;
@@ -2035,7 +2043,7 @@ gc_sweep ()
         if (s->size & ARRAY_MARK_FLAG)
           {
             ((struct Lisp_String *)(&sb->chars[0]))->size
-              &= ~ARRAY_MARK_FLAG & ~MARKBIT;
+              &= ~ARRAY_MARK_FLAG & ~MARKBIT & ~DONT_COPY_FLAG;
             UNMARK_BALANCE_INTERVALS (s->intervals);
             total_string_size += ((struct Lisp_String *)(&sb->chars[0]))->size;
             prev = sb, sb = sb->next;
@@ -2085,13 +2093,14 @@ compact_strings ()
 
           /* NEXTSTR is the old address of the next string.
              Just skip it if it isn't marked.  */
-          if ((EMACS_UINT) size > STRING_BLOCK_SIZE)
+          if (((EMACS_UINT) size & ~DONT_COPY_FLAG) > STRING_BLOCK_SIZE)
             {
               /* It is marked, so its size field is really a chain of refs.
                  Find the end of the chain, where the actual size lives.  */
-              while ((EMACS_UINT) size > STRING_BLOCK_SIZE)
+              while (((EMACS_UINT) size & ~DONT_COPY_FLAG) > STRING_BLOCK_SIZE)
                 {
-                  if (size & 1) size ^= MARKBIT | 1;
+                  if (size & DONT_COPY_FLAG)
+                    size ^= MARKBIT | DONT_COPY_FLAG;
                   size = *(EMACS_INT *)size & ~MARKBIT;
                 }
 
@@ -2125,10 +2134,11 @@ compact_strings ()
                  and make each slot in the chain point to
                  the new address of this string.  */
               size = newaddr->size;
-              while ((EMACS_UINT) size > STRING_BLOCK_SIZE)
+              while (((EMACS_UINT) size & ~DONT_COPY_FLAG) > STRING_BLOCK_SIZE)
                 {
                   register Lisp_Object *objptr;
-                  if (size & 1) size ^= MARKBIT | 1;
+                  if (size & DONT_COPY_FLAG)
+                    size ^= MARKBIT | DONT_COPY_FLAG;
                   objptr = (Lisp_Object *)size;
 
                   size = XFASTINT (*objptr) & ~MARKBIT;