Mark ChangeLog

[pf3gnuchains/gcc-fork.git] / libobjc / init.c

diff --git a/libobjc/init.c b/libobjc/init.c
index ff47f81..23ba41b 100644 (file)
--- a/libobjc/init.c
+++ b/libobjc/init.c
@@ -24,6 +24,10 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 

+/* Uncommented the following line to enable debug logging.  Use this
+   only while debugging the runtime.  */
+/* #define DEBUG 1 */
+

 #include "objc-private/common.h"
 #include "objc-private/error.h"
 #include "objc/runtime.h"
 #include "objc-private/common.h"
 #include "objc-private/error.h"
 #include "objc/runtime.h"


@@ -31,7 +35,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include "objc-private/hash.h"
 #include "objc-private/objc-list.h" 
 #include "objc-private/module-abi-8.h" 
 #include "objc-private/hash.h"
 #include "objc-private/objc-list.h" 
 #include "objc-private/module-abi-8.h" 

-#include "objc-private/runtime.h"
+#include "objc-private/runtime.h"   /* For __objc_resolve_class_links().  */
+#include "objc-private/selector.h"  /* For __sel_register_typed_name().  */

 #include "objc-private/objc-sync.h" /* For __objc_sync_init() */
 #include "objc-private/protocols.h" /* For __objc_protocols_init(),
                                       __objc_protocols_add_protocol()
 #include "objc-private/objc-sync.h" /* For __objc_sync_init() */
 #include "objc-private/protocols.h" /* For __objc_protocols_init(),
                                       __objc_protocols_add_protocol()


@@ -43,8 +48,9 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define OBJC_VERSION 8
 #define PROTOCOL_VERSION 2
 
 #define OBJC_VERSION 8
 #define PROTOCOL_VERSION 2
 

-/* This list contains all modules currently loaded into the
-   runtime.  */
+/* This list contains modules currently loaded into the runtime and
+   for which the +load method (and the load callback, if any) has not
+   been called yet.  */

 static struct objc_list *__objc_module_list = 0;       /* !T:MUTEX */
 
 /* This list contains all proto_list's not yet assigned class
 static struct objc_list *__objc_module_list = 0;       /* !T:MUTEX */
 
 /* This list contains all proto_list's not yet assigned class


@@ -54,6 +60,16 @@ static struct objc_list *unclaimed_proto_list = 0;   /* !T:MUTEX */
 /* List of unresolved static instances.  */
 static struct objc_list *uninitialized_statics = 0;    /* !T:MUTEX */
 
 /* List of unresolved static instances.  */
 static struct objc_list *uninitialized_statics = 0;    /* !T:MUTEX */
 

+/* List of duplicated classes found while loading modules.  If we find
+   a class twice, we ignore it the second time.  On some platforms,
+   where the order in which modules are loaded is well defined, this
+   allows you to replace a class in a shared library by linking in a
+   new implementation which is loaded in in the right order, and which
+   overrides the existing one.
+
+   Protected by __objc_runtime_mutex.  */
+static cache_ptr duplicate_classes = NULL;
+

 /* Global runtime "write" mutex.  Having a single mutex prevents
    deadlocks, but reduces concurrency.  To improve concurrency, some
    groups of functions in the runtime have their own separate mutex
 /* Global runtime "write" mutex.  Having a single mutex prevents
    deadlocks, but reduces concurrency.  To improve concurrency, some
    groups of functions in the runtime have their own separate mutex


@@ -82,46 +98,48 @@ static void __objc_init_protocol (struct objc_protocol *protocol);
 /* Add protocol to class.  */
 static void __objc_class_add_protocols (Class, struct objc_protocol_list *);
 
 /* Add protocol to class.  */
 static void __objc_class_add_protocols (Class, struct objc_protocol_list *);
 

-/* This is a hook which is called by __objc_exec_class every time a
-   class or a category is loaded into the runtime.  This may e.g. help
-   a dynamic loader determine the classes that have been loaded when
-   an object file is dynamically linked in.  */
-/* TODO: This needs to be declared in a public file with the new API.  */
-void (*_objc_load_callback) (Class class, struct objc_category *category); /* !T:SAFE */
+/* Load callback hook.  */
+void (*_objc_load_callback) (Class class, struct objc_category *category) = 0; /* !T:SAFE */

 
 

-/* Are all categories/classes resolved?  */
+/* Are all categories/classes resolved ?  */

 BOOL __objc_dangling_categories = NO;           /* !T:UNUSED */
 
 BOOL __objc_dangling_categories = NO;           /* !T:UNUSED */
 

-/* TODO: This needs to go into objc-private/selector.h.  */
-extern SEL
-__sel_register_typed_name (const char *name, const char *types, 
-                          struct objc_selector *orig, BOOL is_const);
-

 /* Sends +load to all classes and categories in certain
    situations.  */
 static void objc_send_load (void);
 
 /* Inserts all the classes defined in module in a tree of classes that
 /* Sends +load to all classes and categories in certain
    situations.  */
 static void objc_send_load (void);
 
 /* Inserts all the classes defined in module in a tree of classes that

-   resembles the class hierarchy. This tree is traversed in preorder
+   resembles the class hierarchy.  This tree is traversed in preorder

    and the classes in its nodes receive the +load message if these
    and the classes in its nodes receive the +load message if these

-   methods were not executed before. The algorithm ensures that when
+   methods were not executed before.  The algorithm ensures that when

    the +load method of a class is executed all the superclasses have
    been already received the +load message.  */
 static void __objc_create_classes_tree (struct objc_module *module);
 
    the +load method of a class is executed all the superclasses have
    been already received the +load message.  */
 static void __objc_create_classes_tree (struct objc_module *module);
 

-static void __objc_call_callback (struct objc_module *module);
+/* Calls the _objc_load_callback for each class and category in the
+   module (if _objc_load_callback is not NULL).  */
+static void __objc_call_load_callback (struct objc_module *module);

 
 /* A special version that works only before the classes are completely
    installed in the runtime.  */
 static BOOL class_is_subclass_of_class (Class class, Class superclass);
 
 
 /* A special version that works only before the classes are completely
    installed in the runtime.  */
 static BOOL class_is_subclass_of_class (Class class, Class superclass);
 

-typedef struct objc_class_tree {
+/* This is a node in the class tree hierarchy used to send +load
+   messages.  */
+typedef struct objc_class_tree
+{
+  /* The class corresponding to the node.  */

   Class class;
   Class class;

-  struct objc_list *subclasses; /* `head' is pointer to an objc_class_tree */
+
+  /* This is a linked list of all the direct subclasses of this class.
+     'head' points to a subclass node; 'tail' points to the next
+     objc_list node (whose 'head' points to another subclass node,
+     etc).  */
+  struct objc_list *subclasses;

 } objc_class_tree;
 
 } objc_class_tree;
 

-/* This is a linked list of objc_class_tree trees. The head of these
-   trees are root classes (their super class is Nil). These different
+/* This is a linked list of objc_class_tree trees.  The head of these
+   trees are root classes (their super class is Nil).  These different

    trees represent different class hierarchies.  */
 static struct objc_list *__objc_class_tree_list = NULL;
 
    trees represent different class hierarchies.  */
 static struct objc_list *__objc_class_tree_list = NULL;
 


@@ -134,7 +152,7 @@ static cache_ptr __objc_load_methods = NULL;
    is really needed so that superclasses will get the message before
    subclasses.
 
    is really needed so that superclasses will get the message before
    subclasses.
 

-   This tree will contain classes which are being loaded (or have just
+   This tree may contain classes which are being loaded (or have just

    being loaded), and whose super_class pointers have not yet been
    resolved.  This implies that their super_class pointers point to a
    string with the name of the superclass; when the first message is
    being loaded), and whose super_class pointers have not yet been
    resolved.  This implies that their super_class pointers point to a
    string with the name of the superclass; when the first message is


@@ -173,29 +191,30 @@ static Class  class_superclass_of_class (Class class)
 
 
 /* Creates a tree of classes whose topmost class is directly inherited
 
 
 /* Creates a tree of classes whose topmost class is directly inherited

-   from `upper' and the bottom class in this tree is
-   `bottom_class'. The classes in this tree are super classes of
-   `bottom_class'. `subclasses' member of each tree node point to the
-   next subclass tree node.  */
+   from `upper' and the bottom class in this tree is `bottom_class'.
+   If `upper' is Nil, creates a class hierarchy up to a root class.
+   The classes in this tree are super classes of `bottom_class'.  The
+   `subclasses' member of each tree node point to the list of
+   subclasses for the node.  */

 static objc_class_tree *
 create_tree_of_subclasses_inherited_from (Class bottom_class, Class upper)
 {
   Class superclass;
   objc_class_tree *tree, *prev;
 
 static objc_class_tree *
 create_tree_of_subclasses_inherited_from (Class bottom_class, Class upper)
 {
   Class superclass;
   objc_class_tree *tree, *prev;
 

-  if (bottom_class->super_class)
-    superclass = objc_getClass ((char *) bottom_class->super_class);
-  else
-    superclass = Nil;
-

   DEBUG_PRINTF ("create_tree_of_subclasses_inherited_from:");
   DEBUG_PRINTF ("create_tree_of_subclasses_inherited_from:");

-  DEBUG_PRINTF ("bottom_class = %s, upper = %s\n",
+  DEBUG_PRINTF (" bottom_class = %s, upper = %s\n",

                (bottom_class ? bottom_class->name : NULL),
                (upper ? upper->name : NULL));
 
                (bottom_class ? bottom_class->name : NULL),
                (upper ? upper->name : NULL));
 

-  tree = prev = objc_calloc (1, sizeof (objc_class_tree));
+  superclass = class_superclass_of_class (bottom_class);
+
+  prev = objc_calloc (1, sizeof (objc_class_tree));

   prev->class = bottom_class;
 
   prev->class = bottom_class;
 

+  if (superclass == upper)
+    return prev;
+

   while (superclass != upper)
     {
       tree = objc_calloc (1, sizeof (objc_class_tree));
   while (superclass != upper)
     {
       tree = objc_calloc (1, sizeof (objc_class_tree));


@@ -209,23 +228,23 @@ create_tree_of_subclasses_inherited_from (Class bottom_class, Class upper)
 }
 
 /* Insert the `class' into the proper place in the `tree' class
 }
 
 /* Insert the `class' into the proper place in the `tree' class

-   hierarchy. This function returns a new tree if the class has been
+   hierarchy.  This function returns a new tree if the class has been

    successfully inserted into the tree or NULL if the class is not
    successfully inserted into the tree or NULL if the class is not

-   part of the classes hierarchy described by `tree'. This function is
-   private to objc_tree_insert_class (), you should not call it
+   part of the classes hierarchy described by `tree'.  This function
+   is private to objc_tree_insert_class (), you should not call it

    directly.  */
 static objc_class_tree *
 __objc_tree_insert_class (objc_class_tree *tree, Class class)
 {
    directly.  */
 static objc_class_tree *
 __objc_tree_insert_class (objc_class_tree *tree, Class class)
 {

-  DEBUG_PRINTF ("__objc_tree_insert_class: tree = %x, class = %s\n",
-               tree, class->name);
+  DEBUG_PRINTF ("__objc_tree_insert_class: tree = %p (root: %s), class = %s\n",
+               tree, ((tree && tree->class) ? tree->class->name : "Nil"), class->name);

 
   if (tree == NULL)
     return create_tree_of_subclasses_inherited_from (class, NULL);
   else if (class == tree->class)
     {
       /* `class' has been already inserted.  */
 
   if (tree == NULL)
     return create_tree_of_subclasses_inherited_from (class, NULL);
   else if (class == tree->class)
     {
       /* `class' has been already inserted.  */

-      DEBUG_PRINTF ("1. class %s was previously inserted\n", class->name);
+      DEBUG_PRINTF (" 1. class %s was previously inserted\n", class->name);

       return tree;
     }
   else if (class_superclass_of_class (class) == tree->class)
       return tree;
     }
   else if (class_superclass_of_class (class) == tree->class)


@@ -242,7 +261,7 @@ __objc_tree_insert_class (objc_class_tree *tree, Class class)
             the tree.  */
          if (((objc_class_tree *) list->head)->class == class)
            {
             the tree.  */
          if (((objc_class_tree *) list->head)->class == class)
            {

-             DEBUG_PRINTF ("2. class %s was previously inserted\n",
+             DEBUG_PRINTF (" 2. class %s was previously inserted\n",

                            class->name);
              return tree;
            }
                            class->name);
              return tree;
            }


@@ -254,7 +273,7 @@ __objc_tree_insert_class (objc_class_tree *tree, Class class)
       node = objc_calloc (1, sizeof (objc_class_tree));
       node->class = class;
       tree->subclasses = list_cons (node, tree->subclasses);
       node = objc_calloc (1, sizeof (objc_class_tree));
       node->class = class;
       tree->subclasses = list_cons (node, tree->subclasses);

-      DEBUG_PRINTF ("3. class %s inserted\n", class->name);
+      DEBUG_PRINTF (" 3. class %s inserted\n", class->name);

       return tree;
     }
   else
       return tree;
     }
   else


@@ -280,7 +299,7 @@ __objc_tree_insert_class (objc_class_tree *tree, Class class)
                 since nothing has been changed.  */
              subclasses->head
                  = __objc_tree_insert_class (subclasses->head, class);
                 since nothing has been changed.  */
              subclasses->head
                  = __objc_tree_insert_class (subclasses->head, class);

-             DEBUG_PRINTF ("4. class %s inserted\n", class->name);
+             DEBUG_PRINTF (" 4. class %s inserted\n", class->name);

              return tree;
            }
        }
              return tree;
            }
        }


@@ -292,7 +311,7 @@ __objc_tree_insert_class (objc_class_tree *tree, Class class)
        objc_class_tree *new_tree
          = create_tree_of_subclasses_inherited_from (class, tree->class);
        tree->subclasses = list_cons (new_tree, tree->subclasses);
        objc_class_tree *new_tree
          = create_tree_of_subclasses_inherited_from (class, tree->class);
        tree->subclasses = list_cons (new_tree, tree->subclasses);

-       DEBUG_PRINTF ("5. class %s inserted\n", class->name);
+       DEBUG_PRINTF (" 5. class %s inserted\n", class->name);

        return tree;
       }
     }
        return tree;
       }
     }


@@ -304,27 +323,26 @@ objc_tree_insert_class (Class class)
 {
   struct objc_list *list_node;
   objc_class_tree *tree;
 {
   struct objc_list *list_node;
   objc_class_tree *tree;

-
+  

   list_node = __objc_class_tree_list;
   while (list_node)
     {
   list_node = __objc_class_tree_list;
   while (list_node)
     {

+      /* Try to insert the class in this class hierarchy.  */

       tree = __objc_tree_insert_class (list_node->head, class);
       if (tree)
        {
          list_node->head = tree;
       tree = __objc_tree_insert_class (list_node->head, class);
       if (tree)
        {
          list_node->head = tree;

-         break;
+         return;

        }
       else
        list_node = list_node->tail;
     }
        }
       else
        list_node = list_node->tail;
     }

-
-  /* If the list was finished but the class hasn't been inserted,
-     insert it here.  */
-  if (! list_node)
-    {
-      __objc_class_tree_list = list_cons (NULL, __objc_class_tree_list);
-      __objc_class_tree_list->head = __objc_tree_insert_class (NULL, class);
-    }
+  
+  /* If the list was finished but the class hasn't been inserted, we
+     don't have an existing class hierarchy that can accomodate it.
+     Create a new one.  */
+  __objc_class_tree_list = list_cons (NULL, __objc_class_tree_list);
+  __objc_class_tree_list->head = __objc_tree_insert_class (NULL, class);

 }
 
 /* Traverse tree in preorder. Used to send +load.  */
 }
 
 /* Traverse tree in preorder. Used to send +load.  */


@@ -367,56 +385,67 @@ __objc_tree_print (objc_class_tree *tree, int level)
 #endif
 
 /* Walks on a linked list of methods in the reverse order and executes
 #endif
 
 /* Walks on a linked list of methods in the reverse order and executes

-   all the methods corresponding to `op' selector. Walking in the
-   reverse order assures the +load of class is executed first and then
-   +load of categories because of the way in which categories are
-   added to the class methods.  */
+   all the methods corresponding to the `+load' selector.  Walking in
+   the reverse order assures the +load of class is executed first and
+   then +load of categories because of the way in which categories are
+   added to the class methods.  This function needs to be called with
+   the objc_runtime_mutex locked.  */

 static void
 static void

-__objc_send_message_in_list (struct objc_method_list *method_list, Class class, SEL op)
+__objc_send_load_using_method_list (struct objc_method_list *method_list, Class class)

 {
 {

+  static SEL load_selector = 0;

   int i;
 
   int i;
 

-  if (! method_list)
+  if (!method_list)

     return;
 
     return;
 

-  /* First execute the `op' message in the following method lists.  */
-  __objc_send_message_in_list (method_list->method_next, class, op);
+  /* This needs no lock protection because we are called with the
+     objc_runtime_mutex locked.  */
+  if (!load_selector)
+    load_selector = sel_registerName ("load");
+
+  /* method_list is a linked list of method lists; since we're
+     executing in reverse order, we need to do the next list before we
+     do this one.  */
+  __objc_send_load_using_method_list (method_list->method_next, class);

 
   /* Search the method list.  */
   for (i = 0; i < method_list->method_count; i++)
     {
       struct objc_method *mth = &method_list->method_list[i];
 
 
   /* Search the method list.  */
   for (i = 0; i < method_list->method_count; i++)
     {
       struct objc_method *mth = &method_list->method_list[i];
 

-      if (mth->method_name && sel_eq (mth->method_name, op)
+      /* We are searching for +load methods that we haven't executed
+        yet.  */
+      if (mth->method_name && sel_eq (mth->method_name, load_selector)

          && ! objc_hash_is_key_in_hash (__objc_load_methods, mth->method_imp))
        {
          && ! objc_hash_is_key_in_hash (__objc_load_methods, mth->method_imp))
        {

-         /* Add this method into the +load hash table.  */
+         /* Add this method into the +load hash table, so we won't
+            execute it again next time.  */

          objc_hash_add (&__objc_load_methods,
                         mth->method_imp,
                         mth->method_imp);
          
          objc_hash_add (&__objc_load_methods,
                         mth->method_imp,
                         mth->method_imp);
          

-         DEBUG_PRINTF ("sending +load in class: %s\n", class->name);
-         
-         /* The method was found and wasn't previously executed.  */
+         /* Call +load.  */
+         DEBUG_PRINTF (" begin of [%s +load]\n", class->name);

          (*mth->method_imp) ((id)class, mth->method_name);
          (*mth->method_imp) ((id)class, mth->method_name);

+         DEBUG_PRINTF (" end of [%s +load]\n", class->name);

 
          break;
        }
     }
 }
 
 
          break;
        }
     }
 }
 

+/* This function needs to be called with the objc_runtime_mutex
+   locked.  */

 static void
 __objc_send_load (objc_class_tree *tree,
                  int level __attribute__ ((__unused__)))
 {
 static void
 __objc_send_load (objc_class_tree *tree,
                  int level __attribute__ ((__unused__)))
 {

-  static SEL load_sel = 0;

   Class class = tree->class;
   struct objc_method_list *method_list = class->class_pointer->methods;
 
   Class class = tree->class;
   struct objc_method_list *method_list = class->class_pointer->methods;
 

-  if (! load_sel)
-    load_sel = sel_registerName ("load");
-
-  __objc_send_message_in_list (method_list, class, load_sel);
+  DEBUG_PRINTF ("+load: need to send load to class '%s'\n", class->name);
+  __objc_send_load_using_method_list (method_list, class);

 }
 
 static void
 }
 
 static void


@@ -557,11 +586,11 @@ __objc_exec_class (struct objc_module *module)
   struct objc_list **cell;
 
   /* The table of selector references for this module.  */
   struct objc_list **cell;
 
   /* The table of selector references for this module.  */

-  SEL selectors = symtab->refs; 
+  struct objc_selector *selectors = symtab->refs;

 
   int i;
 
 
   int i;
 

-  DEBUG_PRINTF ("received module: %s\n", module->name);
+  DEBUG_PRINTF ("\n__objc_exec_class (%p) - start processing module...\n", module);

 
   /* Check gcc version.  */
   init_check_module_version (module);
 
   /* Check gcc version.  */
   init_check_module_version (module);


@@ -578,7 +607,9 @@ __objc_exec_class (struct objc_module *module)
       __objc_init_selector_tables ();
       __objc_init_class_tables ();
       __objc_init_dispatch_tables ();
       __objc_init_selector_tables ();
       __objc_init_class_tables ();
       __objc_init_dispatch_tables ();

-      __objc_class_tree_list = list_cons (NULL, __objc_class_tree_list);
+      duplicate_classes = objc_hash_new (8,
+                                        (hash_func_type)objc_hash_ptr,
+                                        objc_compare_ptrs);

       __objc_load_methods = objc_hash_new (128, 
                                           (hash_func_type)objc_hash_ptr,
                                           objc_compare_ptrs);
       __objc_load_methods = objc_hash_new (128, 
                                           (hash_func_type)objc_hash_ptr,
                                           objc_compare_ptrs);


@@ -588,31 +619,20 @@ __objc_exec_class (struct objc_module *module)
       previous_constructors = 1;
     }
 
       previous_constructors = 1;
     }
 

-  /* Save the module pointer for later processing. (not currently
-     used).  */
+  /* Save the module pointer so that later we remember to call +load
+     on all classes and categories on it.  */

   objc_mutex_lock (__objc_runtime_mutex);
   __objc_module_list = list_cons (module, __objc_module_list);
 
   objc_mutex_lock (__objc_runtime_mutex);
   __objc_module_list = list_cons (module, __objc_module_list);
 

-  /* Replace referenced selectors from names to SEL's.  */
+  /* Replace referenced selectors from names to SELs.  */

   if (selectors)
     {
   if (selectors)
     {

-      for (i = 0; selectors[i].sel_id; ++i)
-       {
-         const char *name, *type;
-         name = (char *) selectors[i].sel_id;
-         type = (char *) selectors[i].sel_types;
-         /* Constructors are constant static data so we can safely
-            store pointers to them in the runtime
-            structures. is_const == YES.  */
-         __sel_register_typed_name (name, type, 
-                                    (struct objc_selector *) &(selectors[i]),
-                                    YES);
-       }
+      DEBUG_PRINTF (" registering selectors\n");
+      __objc_register_selectors_from_module (selectors);

     }
 
   /* Parse the classes in the load module and gather selector
      information.  */
     }
 
   /* Parse the classes in the load module and gather selector
      information.  */

-  DEBUG_PRINTF ("gathering selectors from module: %s\n", module->name);

   for (i = 0; i < symtab->cls_def_cnt; ++i)
     {
       Class class = (Class) symtab->defs[i];
   for (i = 0; i < symtab->cls_def_cnt; ++i)
     {
       Class class = (Class) symtab->defs[i];


@@ -621,19 +641,29 @@ __objc_exec_class (struct objc_module *module)
       /* Make sure we have what we think.  */
       assert (CLS_ISCLASS (class));
       assert (CLS_ISMETA (class->class_pointer));
       /* Make sure we have what we think.  */
       assert (CLS_ISCLASS (class));
       assert (CLS_ISMETA (class->class_pointer));

-      DEBUG_PRINTF ("phase 1, processing class: %s\n", class->name);
+      DEBUG_PRINTF (" installing class '%s'\n", class->name);
+
+      /* Workaround for a bug in clang: Clang may set flags other than
+        _CLS_CLASS and _CLS_META even when compiling for the
+        traditional ABI (version 8), confusing our runtime.  Try to
+        wipe these flags out.  */
+      if (CLS_ISCLASS (class))
+       __CLS_INFO (class) = _CLS_CLASS;
+      else
+       __CLS_INFO (class) = _CLS_META;

 
       /* Initialize the subclass list to be NULL.  In some cases it
         isn't and this crashes the program.  */
       class->subclass_list = NULL;
 
 
       /* Initialize the subclass list to be NULL.  In some cases it
         isn't and this crashes the program.  */
       class->subclass_list = NULL;
 

-      __objc_init_class (class);
-
-      /* Check to see if the superclass is known in this point. If
-        it's not add the class to the unresolved_classes list.  */
-      if (superclass && ! objc_getClass (superclass))
-       unresolved_classes = list_cons (class, unresolved_classes);
-   }
+      if (__objc_init_class (class))
+       {
+         /* Check to see if the superclass is known in this point. If
+            it's not add the class to the unresolved_classes list.  */
+         if (superclass && ! objc_getClass (superclass))
+           unresolved_classes = list_cons (class, unresolved_classes);
+       }
+    }

 
   /* Process category information from the module.  */
   for (i = 0; i < symtab->cat_def_cnt; ++i)
 
   /* Process category information from the module.  */
   for (i = 0; i < symtab->cat_def_cnt; ++i)


@@ -645,11 +675,7 @@ __objc_exec_class (struct objc_module *module)
         methods.  */
       if (class)
        {
         methods.  */
       if (class)
        {

-
-         DEBUG_PRINTF ("processing categories from (module,object): %s, %s\n",
-                       module->name,
-                       class->name);
-
+         DEBUG_PRINTF (" installing category '%s (%s)'\n", category->class_name, category->category_name);

          /* Do instance methods.  */
          if (category->instance_methods)
            class_add_method_list (class, category->instance_methods);
          /* Do instance methods.  */
          if (category->instance_methods)
            class_add_method_list (class, category->instance_methods);


@@ -671,6 +697,7 @@ __objc_exec_class (struct objc_module *module)
        }
       else
        {
        }
       else
        {

+         DEBUG_PRINTF (" delaying installation of category '%s (%s)'\n", category->class_name, category->category_name);

          /* The object to which the category methods belong can't be
             found.  Save the information.  */
          unclaimed_categories = list_cons (category, unclaimed_categories);
          /* The object to which the category methods belong can't be
             found.  Save the information.  */
          unclaimed_categories = list_cons (category, unclaimed_categories);


@@ -691,9 +718,7 @@ __objc_exec_class (struct objc_module *module)
       
       if (class)
        {
       
       if (class)
        {

-         DEBUG_PRINTF ("attaching stored categories to object: %s\n",
-                       class->name);
-         
+         DEBUG_PRINTF (" installing (delayed) category '%s (%s)'\n", category->class_name, category->category_name);

          list_remove_head (cell);
          
          if (category->instance_methods)
          list_remove_head (cell);
          
          if (category->instance_methods)


@@ -727,17 +752,32 @@ __objc_exec_class (struct objc_module *module)
 
   objc_send_load ();
 
 
   objc_send_load ();
 

+  /* Check if there are no unresolved classes (ie, classes whose
+     superclass has not been loaded yet) and that the 'Object' class,
+     used as the class of classes, exist.  If so, it is worth
+     "resolving the class links" at this point, which will setup all
+     the class/superclass pointers.  */
+  if (!unresolved_classes && objc_getClass ("Object"))
+    {
+      DEBUG_PRINTF (" resolving class links\n");
+      __objc_resolve_class_links ();
+    }
+

   objc_mutex_unlock (__objc_runtime_mutex);
   objc_mutex_unlock (__objc_runtime_mutex);

+
+  DEBUG_PRINTF ("__objc_exec_class (%p) - finished processing module...\n\n", module);

 }
 
 }
 

+/* This function needs to be called with the objc_runtime_mutex
+   locked.  */

 static void
 objc_send_load (void)
 {
 static void
 objc_send_load (void)
 {

-  if (! __objc_module_list)
+  if (!__objc_module_list)

     return;
  
   /* Try to find out if all the classes loaded so far also have their
     return;
  
   /* Try to find out if all the classes loaded so far also have their

-     superclasses known to the runtime. We suppose that the objects
+     superclasses known to the runtime.  We suppose that the objects

      that are allocated in the +load method are in general of a class
      declared in the same module.  */
   if (unresolved_classes)
      that are allocated in the +load method are in general of a class
      declared in the same module.  */
   if (unresolved_classes)


@@ -755,7 +795,7 @@ objc_send_load (void)
 
       /* If we still have classes for whom we don't have yet their
          super classes known to the runtime we don't send the +load
 
       /* If we still have classes for whom we don't have yet their
          super classes known to the runtime we don't send the +load

-         messages.  */
+         messages (and call the load callback) yet.  */

       if (unresolved_classes)
        return;
     }
       if (unresolved_classes)
        return;
     }


@@ -766,7 +806,7 @@ objc_send_load (void)
     return;
 
   /* Iterate over all modules in the __objc_module_list and call on
     return;
 
   /* Iterate over all modules in the __objc_module_list and call on

-     them the __objc_create_classes_tree function. This function
+     them the __objc_create_classes_tree function.  This function

      creates a tree of classes that resembles the class hierarchy.  */
   list_mapcar (__objc_module_list,
               (void (*) (void *)) __objc_create_classes_tree);
      creates a tree of classes that resembles the class hierarchy.  */
   list_mapcar (__objc_module_list,
               (void (*) (void *)) __objc_create_classes_tree);


@@ -784,7 +824,11 @@ objc_send_load (void)
       list_remove_head (&__objc_class_tree_list);
     }
 
       list_remove_head (&__objc_class_tree_list);
     }
 

-  list_mapcar (__objc_module_list, (void (*) (void *)) __objc_call_callback);
+  /* For each module, call the _objc_load_callback if any is
+     defined.  */
+  list_mapcar (__objc_module_list, (void (*) (void *)) __objc_call_load_callback);
+
+  /* Empty the list of modules.  */

   list_free (__objc_module_list);
   __objc_module_list = NULL;
 }
   list_free (__objc_module_list);
   __objc_module_list = NULL;
 }


@@ -802,38 +846,65 @@ __objc_create_classes_tree (struct objc_module *module)
     {
       Class class = (Class) symtab->defs[i];
 
     {
       Class class = (Class) symtab->defs[i];
 

-      objc_tree_insert_class (class);
-    }
-}
-
-static void
-__objc_call_callback (struct objc_module *module)
-{
-  /* The runtime mutex is locked at this point.  */
-  struct objc_symtab *symtab = module->symtab;
-  int i;
-
-  /* Iterate thru classes defined in this module and call the callback
-     for each one.  */
-  for (i = 0; i < symtab->cls_def_cnt; i++)
-    {
-      Class class = (Class) symtab->defs[i];
-
-      /* Call the _objc_load_callback for this class.  */
-      if (_objc_load_callback)
-       _objc_load_callback (class, 0);
+      if (!objc_hash_is_key_in_hash (duplicate_classes, class))
+       objc_tree_insert_class (class);

     }
 
     }
 

-  /* Call the _objc_load_callback for categories. Don't register the
-     instance methods as class methods for categories to root classes
-     since they were already added in the class.  */
-  for (i = 0; i < symtab->cat_def_cnt; i++)
+  /* Now iterate over "claimed" categories too (ie, categories that
+     extend a class that has already been loaded by the runtime), and
+     insert them in the classes tree hiearchy too.  Otherwise, if you
+     add a category, its +load method would not be called if the class
+     is already loaded in the runtime.  It the category is
+     "unclaimed", ie, we haven't loaded the main class yet, postpone
+     sending +load as we want to execute +load from the class before
+     we execute the one from the category.  */
+  for (i = 0; i < symtab->cat_def_cnt; ++i)

     {
       struct objc_category *category = symtab->defs[i + symtab->cls_def_cnt];
       Class class = objc_getClass (category->class_name);
     {
       struct objc_category *category = symtab->defs[i + symtab->cls_def_cnt];
       Class class = objc_getClass (category->class_name);

+      
+      /* If the class for the category exists then append its
+        methods.  */
+      if (class)
+       objc_tree_insert_class (class);
+    }
+}

 
 

-      if (_objc_load_callback)
-       _objc_load_callback (class, category);
+static void
+__objc_call_load_callback (struct objc_module *module)
+{
+  if (_objc_load_callback)
+    {
+      /* The runtime mutex is locked at this point.  */
+      struct objc_symtab *symtab = module->symtab;
+      int i;
+      
+      /* Iterate thru classes defined in this module and call the callback
+        for each one.  */
+      for (i = 0; i < symtab->cls_def_cnt; i++)
+       {
+         Class class = (Class) symtab->defs[i];
+       
+         if (!objc_hash_is_key_in_hash (duplicate_classes, class))
+           {
+             /* Call the _objc_load_callback for this class.  */
+             DEBUG_PRINTF (" calling the load callback for class '%s'\n", class->name);
+             _objc_load_callback (class, 0);
+           }
+       }
+      
+      /* Call the _objc_load_callback for categories.  Don't register
+        the instance methods as class methods for categories to root
+        classes since they were already added in the class.  */
+      for (i = 0; i < symtab->cat_def_cnt; i++)
+       {
+         struct objc_category *category = symtab->defs[i + symtab->cls_def_cnt];
+         Class class = objc_getClass (category->class_name);
+         
+         DEBUG_PRINTF (" calling the load callback for category '%s (%s)'\n",
+                       category->class_name, category->category_name);
+         _objc_load_callback (class, category);
+       }

     }
 }
 
     }
 }
 


@@ -848,27 +919,41 @@ init_check_module_version (struct objc_module *module)
     }
 }
 
     }
 }
 

-/* __objc_init_class must be called with __objc_runtime_mutex already locked.  */
-void
+/* __objc_init_class must be called with __objc_runtime_mutex already
+   locked.  Return YES if the class could be setup; return NO if the
+   class could not be setup because a class with the same name already
+   exists.  */
+BOOL

 __objc_init_class (Class class)
 {
   /* Store the class in the class table and assign class numbers.  */
 __objc_init_class (Class class)
 {
   /* Store the class in the class table and assign class numbers.  */

-  __objc_add_class_to_hash (class);
-  
-  /* Register all of the selectors in the class and meta class.  */
-  __objc_register_selectors_from_class (class);
-  __objc_register_selectors_from_class ((Class) class->class_pointer);
-
-  /* Install the fake dispatch tables.  */
-  __objc_install_premature_dtable (class);
-  __objc_install_premature_dtable (class->class_pointer);
-
-  /* Register the instance methods as class methods, this is only done
-     for root classes.  */
-  __objc_register_instance_methods_to_class (class);
+  if (__objc_add_class_to_hash (class))
+    {
+      /* Register all of the selectors in the class and meta class.  */
+      __objc_register_selectors_from_class (class);
+      __objc_register_selectors_from_class ((Class) class->class_pointer);
+      
+      /* Install the fake dispatch tables.  */
+      __objc_install_premature_dtable (class);
+      __objc_install_premature_dtable (class->class_pointer);
+      
+      /* Register the instance methods as class methods, this is only
+        done for root classes.  */
+      __objc_register_instance_methods_to_class (class);
+      
+      if (class->protocols)
+       __objc_init_protocols (class->protocols);

 
 

-  if (class->protocols)
-    __objc_init_protocols (class->protocols);
+      return YES;
+    }
+  else
+    {
+      /* The module contains a duplicate class.  Remember it so that
+        we will ignore it later.  */
+      DEBUG_PRINTF (" duplicate class '%s' - will be ignored\n", class->name);
+      objc_hash_add (&duplicate_classes, class, class);
+      return NO;
+    }

 }
 
 /* __objc_init_protocol must be called with __objc_runtime_mutex
 }
 
 /* __objc_init_protocol must be called with __objc_runtime_mutex