0.9.0.9:

[sbcl.git] / src / runtime / gc-common.c

diff --git a/src/runtime/gc-common.c b/src/runtime/gc-common.c
index 9b46c42..c083096 100644 (file)
--- a/src/runtime/gc-common.c
+++ b/src/runtime/gc-common.c
@@ -2007,3 +2007,40 @@ component_ptr_from_pc(lispobj *pc)
 
     return (NULL);
 }
+
+/* Scan an area looking for an object which encloses the given pointer.
+ * Return the object start on success or NULL on failure. */
+lispobj *
+gc_search_space(lispobj *start, size_t words, lispobj *pointer)
+{
+    while (words > 0) {
+       size_t count = 1;
+       lispobj thing = *start;
+
+       /* If thing is an immediate then this is a cons. */
+       if (is_lisp_pointer(thing)
+           || (fixnump(thing))
+           || (widetag_of(thing) == CHARACTER_WIDETAG)
+#if N_WORD_BITS == 64
+           || (widetag_of(thing) == SINGLE_FLOAT_WIDETAG)
+#endif
+           || (widetag_of(thing) == UNBOUND_MARKER_WIDETAG))
+           count = 2;
+       else
+           count = (sizetab[widetag_of(thing)])(start);
+
+       /* Check whether the pointer is within this object. */
+       if ((pointer >= start) && (pointer < (start+count))) {
+           /* found it! */
+           /*FSHOW((stderr,"/found %x in %x %x\n", pointer, start, thing));*/
+           return(start);
+       }
+
+       /* Round up the count. */
+       count = CEILING(count,2);
+
+       start += count;
+       words -= count;
+    }
+    return (NULL);
+}