diff --git a/alloc.c b/alloc.c
index 460db192d5..216c23a6f8 100644
--- a/alloc.c
+++ b/alloc.c
@@ -18,26 +18,38 @@
 
 #define BLOCKING 1024
 
-#define DEFINE_ALLOCATOR(name)					\
+#define DEFINE_ALLOCATOR(name, type)				\
 static unsigned int name##_allocs;				\
-struct name *alloc_##name##_node(void)				\
+void *alloc_##name##_node(void)					\
 {								\
 	static int nr;						\
-	static struct name *block;				\
+	static type *block;					\
+	void *ret;						\
 								\
 	if (!nr) {						\
 		nr = BLOCKING;					\
-		block = xcalloc(BLOCKING, sizeof(struct name));	\
+		block = xmalloc(BLOCKING * sizeof(type));	\
 	}							\
 	nr--;							\
 	name##_allocs++;					\
-	return block++;						\
+	ret = block++;						\
+	memset(ret, 0, sizeof(type));				\
+	return ret;						\
 }
 
-DEFINE_ALLOCATOR(blob)
-DEFINE_ALLOCATOR(tree)
-DEFINE_ALLOCATOR(commit)
-DEFINE_ALLOCATOR(tag)
+union any_object {
+	struct object object;
+	struct blob blob;
+	struct tree tree;
+	struct commit commit;
+	struct tag tag;
+};
+
+DEFINE_ALLOCATOR(blob, struct blob)
+DEFINE_ALLOCATOR(tree, struct tree)
+DEFINE_ALLOCATOR(commit, struct commit)
+DEFINE_ALLOCATOR(tag, struct tag)
+DEFINE_ALLOCATOR(object, union any_object)
 
 #ifdef NO_C99_FORMAT
 #define SZ_FMT "%u"
diff --git a/blob.c b/blob.c
index 0a9ea417b8..bd7d078e1a 100644
--- a/blob.c
+++ b/blob.c
@@ -6,12 +6,8 @@ const char *blob_type = "blob";
 struct blob *lookup_blob(const unsigned char *sha1)
 {
 	struct object *obj = lookup_object(sha1);
-	if (!obj) {
-		struct blob *ret = alloc_blob_node();
-		created_object(sha1, &ret->object);
-		ret->object.type = OBJ_BLOB;
-		return ret;
-	}
+	if (!obj)
+		return create_object(sha1, OBJ_BLOB, alloc_blob_node());
 	if (!obj->type)
 		obj->type = OBJ_BLOB;
 	if (obj->type != OBJ_BLOB) {
diff --git a/cache.h b/cache.h
index 05f188558b..89aaf0022d 100644
--- a/cache.h
+++ b/cache.h
@@ -499,14 +499,11 @@ int decode_85(char *dst, const char *line, int linelen);
 void encode_85(char *buf, const unsigned char *data, int bytes);
 
 /* alloc.c */
-struct blob;
-struct tree;
-struct commit;
-struct tag;
-extern struct blob *alloc_blob_node(void);
-extern struct tree *alloc_tree_node(void);
-extern struct commit *alloc_commit_node(void);
-extern struct tag *alloc_tag_node(void);
+extern void *alloc_blob_node(void);
+extern void *alloc_tree_node(void);
+extern void *alloc_commit_node(void);
+extern void *alloc_tag_node(void);
+extern void *alloc_object_node(void);
 extern void alloc_report(void);
 
 /* trace.c */
diff --git a/commit.c b/commit.c
index 952095faa7..10466c4ae0 100644
--- a/commit.c
+++ b/commit.c
@@ -98,12 +98,8 @@ struct commit *lookup_commit_reference(const unsigned char *sha1)
 struct commit *lookup_commit(const unsigned char *sha1)
 {
 	struct object *obj = lookup_object(sha1);
-	if (!obj) {
-		struct commit *ret = alloc_commit_node();
-		created_object(sha1, &ret->object);
-		ret->object.type = OBJ_COMMIT;
-		return ret;
-	}
+	if (!obj)
+		return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
 	if (!obj->type)
 		obj->type = OBJ_COMMIT;
 	return check_commit(obj, sha1, 0);
diff --git a/object.c b/object.c
index 78a44a6ef4..7bd3fec556 100644
--- a/object.c
+++ b/object.c
@@ -105,11 +105,13 @@ static void grow_object_hash(void)
 	obj_hash_size = new_hash_size;
 }
 
-void created_object(const unsigned char *sha1, struct object *obj)
+void *create_object(const unsigned char *sha1, int type, void *o)
 {
+	struct object *obj = o;
+
 	obj->parsed = 0;
 	obj->used = 0;
-	obj->type = OBJ_NONE;
+	obj->type = type;
 	obj->flags = 0;
 	hashcpy(obj->sha1, sha1);
 
@@ -118,25 +120,14 @@ void created_object(const unsigned char *sha1, struct object *obj)
 
 	insert_obj_hash(obj, obj_hash, obj_hash_size);
 	nr_objs++;
+	return obj;
 }
 
-union any_object {
-	struct object object;
-	struct commit commit;
-	struct tree tree;
-	struct blob blob;
-	struct tag tag;
-};
-
 struct object *lookup_unknown_object(const unsigned char *sha1)
 {
 	struct object *obj = lookup_object(sha1);
-	if (!obj) {
-		union any_object *ret = xcalloc(1, sizeof(*ret));
-		created_object(sha1, &ret->object);
-		ret->object.type = OBJ_NONE;
-		return &ret->object;
-	}
+	if (!obj)
+		obj = create_object(sha1, OBJ_NONE, alloc_object_node());
 	return obj;
 }
 
diff --git a/object.h b/object.h
index bdbbc1889c..3e26a0e8b9 100644
--- a/object.h
+++ b/object.h
@@ -46,7 +46,7 @@ extern struct object_refs *lookup_object_refs(struct object *);
 /** Internal only **/
 struct object *lookup_object(const unsigned char *sha1);
 
-void created_object(const unsigned char *sha1, struct object *obj);
+extern void *create_object(const unsigned char *sha1, int type, void *obj);
 
 /** Returns the object, having parsed it to find out what it is. **/
 struct object *parse_object(const unsigned char *sha1);
diff --git a/tag.c b/tag.c
index 56a49f4fe1..330d287924 100644
--- a/tag.c
+++ b/tag.c
@@ -20,13 +20,9 @@ struct object *deref_tag(struct object *o, const char *warn, int warnlen)
 
 struct tag *lookup_tag(const unsigned char *sha1)
 {
-        struct object *obj = lookup_object(sha1);
-        if (!obj) {
-                struct tag *ret = alloc_tag_node();
-                created_object(sha1, &ret->object);
-                ret->object.type = OBJ_TAG;
-                return ret;
-        }
+	struct object *obj = lookup_object(sha1);
+	if (!obj)
+		return create_object(sha1, OBJ_TAG, alloc_tag_node());
 	if (!obj->type)
 		obj->type = OBJ_TAG;
         if (obj->type != OBJ_TAG) {
diff --git a/tree.c b/tree.c
index dbb63fc525..e4a39aa3c3 100644
--- a/tree.c
+++ b/tree.c
@@ -127,12 +127,8 @@ int read_tree(struct tree *tree, int stage, const char **match)
 struct tree *lookup_tree(const unsigned char *sha1)
 {
 	struct object *obj = lookup_object(sha1);
-	if (!obj) {
-		struct tree *ret = alloc_tree_node();
-		created_object(sha1, &ret->object);
-		ret->object.type = OBJ_TREE;
-		return ret;
-	}
+	if (!obj)
+		return create_object(sha1, OBJ_TREE, alloc_tree_node());
 	if (!obj->type)
 		obj->type = OBJ_TREE;
 	if (obj->type != OBJ_TREE) {