* gc.c (heap_min_bound, heap_max_bound): New static globals.

(more): Update heap_min_bound and heap_max_bound.
(in_heap): Do early rejection tests on the pointer. If it's
not aligned, or it's completely outside of the bounding
box of the heap area, short circuit to false.

1 files changed, 13 insertions, 0 deletions

diff --git a/gc.c b/gc.c
index 0582bf0c..1a48ab2f 100644
--- a/gc.c
+++ b/gc.c
@@ -63,6 +63,7 @@ static val **top = prot_stack;
 
 static val free_list, *free_tail = &free_list;
 static heap_t *heap_list;
+static val heap_min_bound, heap_max_bound;
 
 int gc_enabled = 1;
 
@@ -115,6 +116,12 @@ static void more(void)
 
   assert (free_list == 0);
 
+  if (end > heap_max_bound)
+    heap_max_bound = end;
+
+  if (block < heap_min_bound)
+    heap_min_bound = block;
+
   while (block < end) {
     block->t.next = free_list;
     block->t.type = (type_t) FREE;
@@ -277,6 +284,12 @@ static int in_heap(val ptr)
 {
   heap_t *heap;
 
+  if (!is_ptr(ptr))
+    return 0;
+
+  if (ptr < heap_min_bound || ptr >= heap_max_bound)
+    return 0;
+
   for (heap = heap_list; heap != 0; heap = heap->next) {
     if (ptr >= heap->block && ptr < heap->block + HEAP_SIZE)
       if (((char *) ptr - (char *) heap->block) % sizeof (obj_t) == 0)