Do not treat empty map has invalid.

diff --git a/usr.sbin/btrace/btrace.c b/usr.sbin/btrace/btrace.c
index b65fb58..cd63d65 100644 (file)
--- a/usr.sbin/btrace/btrace.c
+++ b/usr.sbin/btrace/btrace.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: btrace.c,v 1.51 2021/09/09 07:03:10 mpi Exp $ */
+/*     $OpenBSD: btrace.c,v 1.52 2021/09/09 07:17:31 mpi Exp $ */
 
 /*
  * Copyright (c) 2019 - 2021 Martin Pieuchot <mpi@openbsd.org>
@@ -749,13 +749,13 @@ stmt_clear(struct bt_stmt *bs)
        assert(bs->bs_var == NULL);
        assert(ba->ba_type == B_AT_VAR);
 
-       if (bv->bv_type != B_VT_MAP && bv->bv_type != B_VT_HIST)
-               errx(1, "invalid variable type for clear(%s)", ba_name(ba));
-
        map = (struct map *)bv->bv_value;
        if (map == NULL)
                return;
 
+       if (bv->bv_type != B_VT_MAP && bv->bv_type != B_VT_HIST)
+               errx(1, "invalid variable type for clear(%s)", ba_name(ba));
+
        map_clear(map);
        bv->bv_value = NULL;
 
@@ -956,13 +956,13 @@ stmt_zero(struct bt_stmt *bs)
        assert(bs->bs_var == NULL);
        assert(ba->ba_type == B_AT_VAR);
 
-       if (bv->bv_type != B_VT_MAP && bv->bv_type != B_VT_HIST)
-               errx(1, "invalid variable type for zero(%s)", ba_name(ba));
-
        map = (struct map *)bv->bv_value;
        if (map == NULL)
                return;
 
+       if (bv->bv_type != B_VT_MAP && bv->bv_type != B_VT_HIST)
+               errx(1, "invalid variable type for zero(%s)", ba_name(ba));
+
        map_zero(map);
 
        debug("map=%p '%s' zero\n", map, bv_name(bv));