X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fir%2Firhooks.c;h=b32b91e76b0b798916d37730a56f3f68c436470a;hb=337d80943727432a91e53ef5b5554eac00a7b7da;hp=490b77ed57363b15da6048760d7ce079e150b4f0;hpb=8ccfe04ca59ff56fc32b2323b80cee2a5194694d;p=libfirm

diff --git a/ir/ir/irhooks.c b/ir/ir/irhooks.c
index 490b77ed5..b32b91e76 100644
--- a/ir/ir/irhooks.c
+++ b/ir/ir/irhooks.c
@@ -21,27 +21,28 @@
  * @file
  * @brief    Generic hooks for various libFirm functions.
  * @author   Michael Beck
- * @version  $Id$
  */
 #include "config.h"
 
+#include <assert.h>
+
 #include "irhooks.h"
 
-/* the hooks */
 hook_entry_t *hooks[hook_last];
 
-/* register a hook */
 void register_hook(hook_type_t hook, hook_entry_t *entry)
 {
   /* check if a hook function is specified. It's a union, so no matter which one */
   if (! entry->hook._hook_turn_into_id)
     return;
 
+  /* hook should not be registered yet */
+  assert(entry->next == NULL && hooks[hook] != entry);
+
   entry->next = hooks[hook];
   hooks[hook] = entry;
 }
 
-/* unregister a hook */
 void unregister_hook(hook_type_t hook, hook_entry_t *entry)
 {
   hook_entry_t *p;