--- /dev/null
+++ libmalloc/libmalloc-140.40.1/src/radix_tree_debug.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2017 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#include <radix_tree.h>
+#include <radix_tree_internal.h>
+
+#include <stdio.h>
+
+static
+bool
+radix_tree_fsck_recursive(struct radix_tree *tree, struct radix_node *node,
+						  uint64_t key, int keyshift,
+						  uint64_t min)
+{
+	bool ok = true;
+	for (int i = 0; i < 2; i++) {
+		struct radix_edge *edge = &node->edges[i];
+		if (edge->labelBits == 0)
+			continue;
+
+		uint64_t edgekey = extend_key(key, edge->labelBits, keyshift, edge->label);
+
+		if (edge->isLeaf) {
+			if (edgekey < min)
+			{
+				fprintf(stderr, "!!!! node=%p min=%llx edge=%d edgekey=%llx\n", node, min, i, edgekey);
+				return false;
+			}
+
+			struct radix_node *leaf = getnode(tree, edge->index);
+			min = edgekey + leaf_size(tree, leaf);
+		} else {
+			ok = ok && radix_tree_fsck_recursive(tree, getnode(tree, edge->index), edgekey, keyshift+edge->labelBits, min);
+		}
+	}
+	return ok;
+}
+
+bool
+radix_tree_fsck(struct radix_tree *tree)
+{
+	return radix_tree_fsck_recursive(tree, getnode(tree, 0), 0, 0, 0);
+}
+
+static
+void
+radix_tree_print_recursive(struct radix_tree *tree, struct radix_node *node, int indent,
+						   uint64_t key, int keyshift) {
+	if (node->edges[0].labelBits == 0 && node->edges[1].labelBits == 0) {
+		printf("%p:", node);
+		for (int i = 0; i < indent; i++) printf(" ");
+		printf("empty\n");
+	}
+	for (int i = 0; i < 2; i++) {
+		struct radix_edge *edge = &node->edges[i];
+		if (edge->labelBits == 0)
+			continue;
+		printf("%p:", node);
+		for (int i = 0; i < indent; i++) printf(" ");
+		printf ("0x%x/%d", edge->label, edge->labelBits);
+		if (edge->isLeaf) {
+			struct radix_node *leaf = getnode(tree, edge->index);
+			printf(" [%llx-%llx] -> stack=%llx\n",
+				   extend_key(key, edge->labelBits, keyshift, edge->label),
+				   extend_key(key, edge->labelBits, keyshift, edge->label) + leaf_size(tree, leaf),
+				   leaf->stackid);
+		} else {
+			printf("\n");
+			radix_tree_print_recursive(tree, getnode(tree, edge->index), indent + 4,
+									   extend_key(key, edge->labelBits, keyshift, edge->label),
+									   keyshift + edge->labelBits);
+		}
+	}
+}
+
+void
+radix_tree_print(struct radix_tree *tree)
+{
+	radix_tree_print_recursive(tree, getnode(tree, 0), 0, 0, 0);
+}