verify: Clarify assertion message.

[libfirm] / ir / ir / irhooks.c

diff --git a/ir/ir/irhooks.c b/ir/ir/irhooks.c
index e5b6bcf..b32b91e 100644 (file)
--- 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;
@@ -52,7 +53,8 @@ void unregister_hook(hook_type_t hook, hook_entry_t *entry)
     return;
   }
 
-  for (p = hooks[hook]; p && p->next != entry; p = p->next);
+  for (p = hooks[hook]; p && p->next != entry; p = p->next) {
+  }
 
   if (p) {
     p->next     = entry->next;