ssort: gc bug in vector case.

* gc.[ch] (gc_prot_array_alloc): Return the COBJ via
new pointer argument.

* lib.c (ssort_vec): Capture the object from gt_prot_array_alloc
into a local variable, That makes it visible to the garbage
collector, so it won't be prematurely reclaimed. Since we don't
use or return that object, we need to use gc_hint.

3 files changed, 6 insertions, 4 deletions

diff --git a/gc.c b/gc.c
index 41f0c6d2..088508d9 100644
--- a/gc.c
+++ b/gc.c
@@ -1321,13 +1321,13 @@ static struct cobj_ops prot_array_ops = cobj_ops_init(eq,
                                                       prot_array_mark,
                                                       cobj_eq_hash_op);
 
-val *gc_prot_array_alloc(cnum size)
+val *gc_prot_array_alloc(cnum size, val *obj)
 {
   struct prot_array *pa = coerce(struct prot_array *,
                                  chk_calloc(offsetof(struct prot_array, arr) +
                                             size * sizeof(val), 1));
   pa->size = size;
-  pa->self = cobj(coerce(mem_t *, pa), prot_array_cls, &prot_array_ops);
+  *obj = pa->self = cobj(coerce(mem_t *, pa), prot_array_cls, &prot_array_ops);
 
   return pa->arr;
 }
diff --git a/gc.h b/gc.h
index 464268bf..1b34b82c 100644
--- a/gc.h
+++ b/gc.h
@@ -88,5 +88,5 @@ INLINE void gc_stack_check(void)
     gc_stack_overflow();
 }
 
-val *gc_prot_array_alloc(cnum size);
+val *gc_prot_array_alloc(cnum size, val *obj);
 void gc_prot_array_free(val *);
diff --git a/lib.c b/lib.c
index 422cb693..b5eb4d1e 100644
--- a/lib.c
+++ b/lib.c
@@ -11094,9 +11094,11 @@ static void mergesort(val vec, val lessfun, val keyfun, cnum from, cnum to,
 static void ssort_vec(val vec, val lessfun, val keyfun, val self)
 {
   cnum len = c_fixnum(length(vec), self);
-  val *aux = gc_prot_array_alloc(len);
+  val auxobj;
+  val *aux = gc_prot_array_alloc(len, &auxobj);
   mergesort(vec, lessfun, keyfun, 0, len, aux);
   gc_prot_array_free(aux);
+  gc_hint(auxobj);
 }