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/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(),
#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
/* 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
/* 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 */
/* Sends +load to all classes and categories in certain
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
- 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);
-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);
-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;
- 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;
-/* 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;
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
/* 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;
- 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 ("bottom_class = %s, upper = %s\n",
+ DEBUG_PRINTF (" bottom_class = %s, upper = %s\n",
(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;
+ if (superclass == upper)
+ return prev;
+
while (superclass != upper)
{
tree = objc_calloc (1, sizeof (objc_class_tree));
}
/* 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
- 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)
{
- 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. */
- 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)
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;
}
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
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;
}
}
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;
}
}
{
struct objc_list *list_node;
objc_class_tree *tree;
-
+
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;
- break;
+ return;
}
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. */
#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
-__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;
- if (! method_list)
+ if (!method_list)
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];
- 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))
{
- /* 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);
- 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);
+ DEBUG_PRINTF (" end of [%s +load]\n", class->name);
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 SEL load_sel = 0;
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
struct objc_list **cell;
/* The table of selector references for this module. */
- SEL selectors = symtab->refs;
+ struct objc_selector *selectors = symtab->refs;
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);
__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);
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);
- /* Replace referenced selectors from names to SEL's. */
+ /* Replace referenced selectors from names to SELs. */
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. */
- 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];
/* 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;
- __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)
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);
}
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);
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)
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);
+
+ 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)
{
- if (! __objc_module_list)
+ if (!__objc_module_list)
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)
/* 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;
}
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);
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;
}
{
Class class = (Class) symtab->defs[i];
- objc_tree_insert_class (class);
+ if (!objc_hash_is_key_in_hash (duplicate_classes, class))
+ 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);
- }
-
- /* 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);
+
+ /* 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);
+ }
}
}
}
}
-/* __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_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
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