/* GNU Objective C Runtime message lookup
Copyright (C) 1993, 1995, 1996, 1997, 1998,
- 2001, 2002, 2004, 2009 Free Software Foundation, Inc.
+ 2001, 2002, 2004, 2009, 2010 Free Software Foundation, Inc.
Contributed by Kresten Krab Thorup
This file is part of GCC.
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 */
/* FIXME: This file has no business including tm.h. */
/* FIXME: This should be using libffi instead of __builtin_apply
and friends. */
+#include "objc-private/common.h"
+#include "objc-private/error.h"
#include "tconfig.h"
#include "coretypes.h"
#include "tm.h"
-#include "objc/objc.h"
-#include "objc/objc-api.h"
+#include "objc/runtime.h"
+#include "objc/message.h" /* For objc_msg_lookup(), objc_msg_lookup_super(). */
#include "objc/thr.h"
-#include "objc/hash.h"
-#include "objc/objc-list.h"
+#include "objc-private/module-abi-8.h"
#include "objc-private/runtime.h"
-#include "objc/sarray.h"
-#include "objc/encoding.h"
+#include "objc-private/hash.h"
+#include "objc-private/sarray.h"
+#include "objc-private/selector.h" /* For sel_is_mapped() */
#include "runtime-info.h"
+#include <assert.h> /* For assert */
+#include <string.h> /* For strlen */
/* This is how we hack STRUCT_VALUE to be 1 or 0. */
#define gen_rtx(args...) 1
#define gen_rtx_MEM(args...) 1
#define gen_rtx_REG(args...) 1
-/* Alread defined in gcc/coretypes.h. So prevent double definition warning. */
+/* Already defined in gcc/coretypes.h. So prevent double definition warning. */
#undef rtx
#define rtx int
#define INVISIBLE_STRUCT_RETURN 0
#endif
-/* The uninstalled dispatch table */
+/* The uninstalled dispatch table. If a class' dispatch table points
+ to __objc_uninstalled_dtable then that means it needs its dispatch
+ table to be installed. */
struct sarray *__objc_uninstalled_dtable = 0; /* !T:MUTEX */
-/* Two hooks for method forwarding. If either is set, it is invoked
- * to return a function that performs the real forwarding. If both
- * are set, the result of __objc_msg_forward2 will be preferred over
- * that of __objc_msg_forward. If both return NULL or are unset,
- * the libgcc based functions (__builtin_apply and friends) are
- * used.
- */
+/* Two hooks for method forwarding. If either is set, it is invoked to
+ * return a function that performs the real forwarding. If both are
+ * set, the result of __objc_msg_forward2 will be preferred over that
+ * of __objc_msg_forward. If both return NULL or are unset, the
+ * libgcc based functions (__builtin_apply and friends) are used. */
IMP (*__objc_msg_forward) (SEL) = NULL;
IMP (*__objc_msg_forward2) (id, SEL) = NULL;
-/* Send +initialize to class */
+/* Send +initialize to class. */
static void __objc_send_initialize (Class);
-static void __objc_install_dispatch_table_for_class (Class);
-
/* Forward declare some functions */
-static void __objc_init_install_dtable (id, SEL);
+static void __objc_install_dtable_for_class (Class cls);
+static void __objc_prepare_dtable_for_class (Class cls);
+static void __objc_install_prepared_dtable_for_class (Class cls);
+
+static struct sarray *__objc_prepared_dtable_for_class (Class cls);
+static IMP __objc_get_prepared_imp (Class cls,SEL sel);
+
/* Various forwarding functions that are used based upon the
return type for the selector.
__objc_block_forward for structures.
__objc_double_forward for floats/doubles.
- __objc_word_forward for pointers or types that fit in registers. */
+ __objc_word_forward for pointers or types that fit in registers. */
static double __objc_double_forward (id, SEL, ...);
static id __objc_word_forward (id, SEL, ...);
typedef struct { id many[8]; } __big;
static id
#endif
__objc_block_forward (id, SEL, ...);
-static Method_t search_for_method_in_hierarchy (Class class, SEL sel);
-Method_t search_for_method_in_list (MethodList_t list, SEL op);
+static struct objc_method * search_for_method_in_hierarchy (Class class, SEL sel);
+struct objc_method * search_for_method_in_list (struct objc_method_list * list, SEL op);
id nil_method (id, SEL);
-/* Given a selector, return the proper forwarding implementation. */
+/* Given a selector, return the proper forwarding implementation. */
inline
IMP
__objc_get_forward_imp (id rcv, SEL sel)
{
- /* If a custom forwarding hook was registered, try getting a forwarding
- function from it. There are two forward routine hooks, one that
- takes the receiver as an argument and one that does not. */
+ /* If a custom forwarding hook was registered, try getting a
+ forwarding function from it. There are two forward routine hooks,
+ one that takes the receiver as an argument and one that does
+ not. */
if (__objc_msg_forward2)
{
IMP result;
{
IMP result;
if ((result = __objc_msg_forward (sel)) != NULL)
- return result;
+ return result;
}
- /* In all other cases, use the default forwarding functions built using
- __builtin_apply and friends. */
+ /* In all other cases, use the default forwarding functions built
+ using __builtin_apply and friends. */
{
const char *t = sel->sel_types;
-
+
if (t && (*t == '[' || *t == '(' || *t == '{')
#ifdef OBJC_MAX_STRUCT_BY_VALUE
&& objc_sizeof_type (t) > OBJC_MAX_STRUCT_BY_VALUE
}
}
-/* Given a class and selector, return the selector's implementation. */
+/* Selectors for +resolveClassMethod: and +resolveInstanceMethod:.
+ These are set up at startup. */
+static SEL selector_resolveClassMethod = NULL;
+static SEL selector_resolveInstanceMethod = NULL;
+
+/* Internal routines use to resolve a class method using
+ +resolveClassMethod:. 'class' is always a non-Nil class (*not* a
+ meta-class), and 'sel' is the selector that we are trying to
+ resolve. This must be called when class is not Nil, and the
+ dispatch table for class methods has already been installed.
+
+ This routine tries to call +resolveClassMethod: to give an
+ opportunity to resolve the method. If +resolveClassMethod: returns
+ YES, it tries looking up the method again, and if found, it returns
+ it. Else, it returns NULL. */
+static inline
+IMP
+__objc_resolve_class_method (Class class, SEL sel)
+{
+ /* We need to lookup +resolveClassMethod:. */
+ BOOL (*resolveMethodIMP) (id, SEL, SEL);
+
+ /* The dispatch table for class methods is already installed and we
+ don't want any forwarding to happen when looking up this method,
+ so we just look it up directly. Note that if 'sel' is precisely
+ +resolveClassMethod:, this would look it up yet again and find
+ nothing. That's no problem and there's no recursion. */
+ resolveMethodIMP = (BOOL (*) (id, SEL, SEL))sarray_get_safe
+ (class->class_pointer->dtable, (size_t) selector_resolveClassMethod->sel_id);
+
+ if (resolveMethodIMP && resolveMethodIMP ((id)class, selector_resolveClassMethod, sel))
+ {
+ /* +resolveClassMethod: returned YES. Look the method up again.
+ We already know the dtable is installed. */
+
+ /* TODO: There is the case where +resolveClassMethod: is buggy
+ and returned YES without actually adding the method. We
+ could maybe print an error message. */
+ return sarray_get_safe (class->class_pointer->dtable, (size_t) sel->sel_id);
+ }
+
+ return NULL;
+}
+
+/* Internal routines use to resolve a instance method using
+ +resolveInstanceMethod:. 'class' is always a non-Nil class, and
+ 'sel' is the selector that we are trying to resolve. This must be
+ called when class is not Nil, and the dispatch table for instance
+ methods has already been installed.
+
+ This routine tries to call +resolveInstanceMethod: to give an
+ opportunity to resolve the method. If +resolveInstanceMethod:
+ returns YES, it tries looking up the method again, and if found, it
+ returns it. Else, it returns NULL. */
+static inline
+IMP
+__objc_resolve_instance_method (Class class, SEL sel)
+{
+ /* We need to lookup +resolveInstanceMethod:. */
+ BOOL (*resolveMethodIMP) (id, SEL, SEL);
+
+ /* The dispatch table for class methods may not be already installed
+ so we have to install it if needed. */
+ resolveMethodIMP = sarray_get_safe (class->class_pointer->dtable,
+ (size_t) selector_resolveInstanceMethod->sel_id);
+ if (resolveMethodIMP == 0)
+ {
+ /* Try again after installing the dtable. */
+ if (class->class_pointer->dtable == __objc_uninstalled_dtable)
+ {
+ objc_mutex_lock (__objc_runtime_mutex);
+ if (class->class_pointer->dtable == __objc_uninstalled_dtable)
+ __objc_install_dtable_for_class (class->class_pointer);
+ objc_mutex_unlock (__objc_runtime_mutex);
+ }
+ resolveMethodIMP = sarray_get_safe (class->class_pointer->dtable,
+ (size_t) selector_resolveInstanceMethod->sel_id);
+ }
+
+ if (resolveMethodIMP && resolveMethodIMP ((id)class, selector_resolveInstanceMethod, sel))
+ {
+ /* +resolveInstanceMethod: returned YES. Look the method up
+ again. We already know the dtable is installed. */
+
+ /* TODO: There is the case where +resolveInstanceMethod: is
+ buggy and returned YES without actually adding the method.
+ We could maybe print an error message. */
+ return sarray_get_safe (class->dtable, (size_t) sel->sel_id);
+ }
+
+ return NULL;
+}
+
+/* Given a CLASS and selector, return the implementation corresponding
+ to the method of the selector.
+
+ If CLASS is a class, the instance method is returned.
+ If CLASS is a meta class, the class method is returned.
+
+ Since this requires the dispatch table to be installed, this function
+ will implicitly invoke +initialize for CLASS if it hasn't been
+ invoked yet. This also insures that +initialize has been invoked
+ when the returned implementation is called directly.
+
+ The forwarding hooks require the receiver as an argument (if they are to
+ perform dynamic lookup in proxy objects etc), so this function has a
+ receiver argument to be used with those hooks. */
+static inline
+IMP
+get_implementation (id receiver, Class class, SEL sel)
+{
+ void *res;
+
+ if (class->dtable == __objc_uninstalled_dtable)
+ {
+ /* The dispatch table needs to be installed. */
+ objc_mutex_lock (__objc_runtime_mutex);
+
+ /* Double-checked locking pattern: Check
+ __objc_uninstalled_dtable again in case another thread
+ installed the dtable while we were waiting for the lock to be
+ released. */
+ if (class->dtable == __objc_uninstalled_dtable)
+ __objc_install_dtable_for_class (class);
+
+ /* If the dispatch table is not yet installed, we are still in
+ the process of executing +initialize. But the implementation
+ pointer should be available in the prepared ispatch table if
+ it exists at all. */
+ if (class->dtable == __objc_uninstalled_dtable)
+ {
+ assert (__objc_prepared_dtable_for_class (class) != 0);
+ res = __objc_get_prepared_imp (class, sel);
+ }
+ else
+ res = 0;
+
+ objc_mutex_unlock (__objc_runtime_mutex);
+ /* Call ourselves with the installed dispatch table and get the
+ real method. */
+ if (!res)
+ res = get_implementation (receiver, class, sel);
+ }
+ else
+ {
+ /* The dispatch table has been installed. */
+ res = sarray_get_safe (class->dtable, (size_t) sel->sel_id);
+ if (res == 0)
+ {
+ /* The dispatch table has been installed, and the method is
+ not in the dispatch table. So the method just doesn't
+ exist for the class. */
+
+ /* Try going through the +resolveClassMethod: or
+ +resolveInstanceMethod: process. */
+ if (CLS_ISMETA (class))
+ {
+ /* We have the meta class, but we need to invoke the
+ +resolveClassMethod: method on the class. So, we
+ need to obtain the class from the meta class, which
+ we do using the fact that both the class and the
+ meta-class have the same name. */
+ Class realClass = objc_lookUpClass (class->name);
+ if (realClass)
+ res = __objc_resolve_class_method (realClass, sel);
+ }
+ else
+ res = __objc_resolve_instance_method (class, sel);
+
+ if (res == 0)
+ res = __objc_get_forward_imp (receiver, sel);
+ }
+ }
+ return res;
+}
+
inline
IMP
get_imp (Class class, SEL sel)
void *res = sarray_get_safe (class->dtable, (size_t) sel->sel_id);
if (res == 0)
{
- /* Not a valid method */
- if (class->dtable == __objc_uninstalled_dtable)
- {
- /* The dispatch table needs to be installed. */
- objc_mutex_lock (__objc_runtime_mutex);
-
- /* Double-checked locking pattern: Check
- __objc_uninstalled_dtable again in case another thread
- installed the dtable while we were waiting for the lock
- to be released. */
- if (class->dtable == __objc_uninstalled_dtable)
- {
- __objc_install_dispatch_table_for_class (class);
- }
-
- objc_mutex_unlock (__objc_runtime_mutex);
- /* Call ourselves with the installed dispatch table
- and get the real method */
- res = get_imp (class, sel);
- }
- else
- {
- /* The dispatch table has been installed. */
-
- /* Get the method from the dispatch table (we try to get it
- again in case another thread has installed the dtable just
- after we invoked sarray_get_safe, but before we checked
- class->dtable == __objc_uninstalled_dtable).
- */
- res = sarray_get_safe (class->dtable, (size_t) sel->sel_id);
- if (res == 0)
- {
- /* The dispatch table has been installed, and the method
- is not in the dispatch table. So the method just
- doesn't exist for the class. Return the forwarding
- implementation. */
- res = __objc_get_forward_imp ((id)class, sel);
- }
- }
+ res = get_implementation(nil, class, sel);
}
return res;
}
+/* The new name of get_imp(). */
+IMP
+class_getMethodImplementation (Class class_, SEL selector)
+{
+ if (class_ == Nil || selector == NULL)
+ return NULL;
+
+ /* get_imp is inlined, so we're good. */
+ return get_imp (class_, selector);
+}
+
+/* Given a method, return its implementation. This has been replaced
+ by method_getImplementation() in the modern API. */
+IMP
+method_get_imp (struct objc_method * method)
+{
+ return (method != (struct objc_method *)0) ? method->method_imp : (IMP)0;
+}
+
/* Query if an object can respond to a selector, returns YES if the
-object implements the selector otherwise NO. Does not check if the
-method can be forwarded. */
+ object implements the selector otherwise NO. Does not check if the
+ method can be forwarded. Since this requires the dispatch table to
+ installed, this function will implicitly invoke +initialize for the
+ class of OBJECT if it hasn't been invoked yet. */
inline
BOOL
__objc_responds_to (id object, SEL sel)
{
void *res;
+ struct sarray *dtable;
/* Install dispatch table if need be */
- if (object->class_pointer->dtable == __objc_uninstalled_dtable)
+ dtable = object->class_pointer->dtable;
+ if (dtable == __objc_uninstalled_dtable)
{
objc_mutex_lock (__objc_runtime_mutex);
if (object->class_pointer->dtable == __objc_uninstalled_dtable)
- {
- __objc_install_dispatch_table_for_class (object->class_pointer);
- }
+ __objc_install_dtable_for_class (object->class_pointer);
+
+ /* If the dispatch table is not yet installed, we are still in
+ the process of executing +initialize. Yet the dispatch table
+ should be available. */
+ if (object->class_pointer->dtable == __objc_uninstalled_dtable)
+ {
+ dtable = __objc_prepared_dtable_for_class (object->class_pointer);
+ assert (dtable);
+ }
+ else
+ dtable = object->class_pointer->dtable;
+
objc_mutex_unlock (__objc_runtime_mutex);
}
- /* Get the method from the dispatch table */
- res = sarray_get_safe (object->class_pointer->dtable, (size_t) sel->sel_id);
- return (res != 0);
+ /* Get the method from the dispatch table. */
+ res = sarray_get_safe (dtable, (size_t) sel->sel_id);
+ return (res != 0) ? YES : NO;
}
-/* This is the lookup function. All entries in the table are either a
+BOOL
+class_respondsToSelector (Class class_, SEL selector)
+{
+ struct sarray *dtable;
+ void *res;
+
+ if (class_ == Nil || selector == NULL)
+ return NO;
+
+ /* Install dispatch table if need be. */
+ dtable = class_->dtable;
+ if (dtable == __objc_uninstalled_dtable)
+ {
+ objc_mutex_lock (__objc_runtime_mutex);
+ if (class_->dtable == __objc_uninstalled_dtable)
+ __objc_install_dtable_for_class (class_);
+
+ /* If the dispatch table is not yet installed,
+ we are still in the process of executing +initialize.
+ Yet the dispatch table should be available. */
+ if (class_->dtable == __objc_uninstalled_dtable)
+ {
+ dtable = __objc_prepared_dtable_for_class (class_);
+ assert (dtable);
+ }
+ else
+ dtable = class_->dtable;
+
+ objc_mutex_unlock (__objc_runtime_mutex);
+ }
+
+ /* Get the method from the dispatch table. */
+ res = sarray_get_safe (dtable, (size_t) selector->sel_id);
+ return (res != 0) ? YES : NO;
+}
+
+/* This is the lookup function. All entries in the table are either a
valid method *or* zero. If zero then either the dispatch table
- needs to be installed or it doesn't exist and forwarding is attempted. */
-inline
+ needs to be installed or it doesn't exist and forwarding is
+ attempted. */
IMP
objc_msg_lookup (id receiver, SEL op)
{
IMP result;
if (receiver)
{
+ /* First try a quick lookup assuming the dispatch table exists. */
result = sarray_get_safe (receiver->class_pointer->dtable,
(sidx)op->sel_id);
if (result == 0)
{
- /* Not a valid method */
- if (receiver->class_pointer->dtable == __objc_uninstalled_dtable)
- {
- /* The dispatch table needs to be installed.
- This happens on the very first method call to the class. */
- __objc_init_install_dtable (receiver, op);
-
- /* Get real method for this in newly installed dtable */
- result = get_imp (receiver->class_pointer, op);
- }
- else
- {
- /* The dispatch table has been installed. Check again
- if the method exists (just in case the dispatch table
- has been installed by another thread after we did the
- previous check that the method exists).
- */
- result = sarray_get_safe (receiver->class_pointer->dtable,
- (sidx)op->sel_id);
- if (result == 0)
- {
- /* If the method still just doesn't exist for the
- class, attempt to forward the method. */
- result = __objc_get_forward_imp (receiver, op);
- }
- }
+ /* Not found ... call get_implementation () to install the
+ dispatch table and call +initialize as required,
+ providing the method implementation or a forwarding
+ function. */
+ result = get_implementation (receiver, receiver->class_pointer, op);
}
return result;
}
}
IMP
-objc_msg_lookup_super (Super_t super, SEL sel)
+objc_msg_lookup_super (struct objc_super *super, SEL sel)
{
if (super->self)
- return get_imp (super->class, sel);
+ return get_imp (super->super_class, sel);
else
return (IMP)nil_method;
}
-int method_get_sizeof_arguments (Method *);
-
-retval_t
-objc_msg_sendv (id object, SEL op, arglist_t arg_frame)
-{
- Method *m = class_get_instance_method (object->class_pointer, op);
- const char *type;
- *((id *) method_get_first_argument (m, arg_frame, &type)) = object;
- *((SEL *) method_get_next_argument (arg_frame, &type)) = op;
- return __builtin_apply ((apply_t) m->method_imp,
- arg_frame,
- method_get_sizeof_arguments (m));
-}
-
void
__objc_init_dispatch_tables ()
{
__objc_uninstalled_dtable = sarray_new (200, 0);
-}
-/* This function is called by objc_msg_lookup when the
- dispatch table needs to be installed; thus it is called once
- for each class, namely when the very first message is sent to it. */
-static void
-__objc_init_install_dtable (id receiver, SEL op __attribute__ ((__unused__)))
-{
- objc_mutex_lock (__objc_runtime_mutex);
-
- /* This may happen, if the programmer has taken the address of a
- method before the dtable was initialized... too bad for him! */
- if (receiver->class_pointer->dtable != __objc_uninstalled_dtable)
- {
- objc_mutex_unlock (__objc_runtime_mutex);
- return;
- }
-
- if (CLS_ISCLASS (receiver->class_pointer))
- {
- /* receiver is an ordinary object */
- assert (CLS_ISCLASS (receiver->class_pointer));
-
- /* install instance methods table */
- __objc_install_dispatch_table_for_class (receiver->class_pointer);
-
- /* call +initialize -- this will in turn install the factory
- dispatch table if not already done :-) */
- __objc_send_initialize (receiver->class_pointer);
- }
- else
- {
- /* receiver is a class object */
- assert (CLS_ISCLASS ((Class)receiver));
- assert (CLS_ISMETA (receiver->class_pointer));
-
- /* Install real dtable for factory methods */
- __objc_install_dispatch_table_for_class (receiver->class_pointer);
-
- __objc_send_initialize ((Class)receiver);
- }
- objc_mutex_unlock (__objc_runtime_mutex);
+ /* TODO: It would be cool to register typed selectors here. */
+ selector_resolveClassMethod = sel_registerName ("resolveClassMethod:");
+ selector_resolveInstanceMethod = sel_registerName ("resolveInstanceMethod:");
}
+
/* Install dummy table for class which causes the first message to
- that class (or instances hereof) to be initialized properly */
+ that class (or instances hereof) to be initialized properly. */
void
__objc_install_premature_dtable (Class class)
{
class->dtable = __objc_uninstalled_dtable;
}
-/* Send +initialize to class if not already done */
+/* Send +initialize to class if not already done. */
static void
__objc_send_initialize (Class class)
{
- /* This *must* be a class object */
+ /* This *must* be a class object. */
assert (CLS_ISCLASS (class));
assert (! CLS_ISMETA (class));
+ /* class_add_method_list/__objc_update_dispatch_table_for_class may
+ have reset the dispatch table. The canonical way to insure that
+ we send +initialize just once, is this flag. */
if (! CLS_ISINITIALIZED (class))
{
+ DEBUG_PRINTF ("+initialize: need to initialize class '%s'\n", class->name);
CLS_SETINITIALIZED (class);
CLS_SETINITIALIZED (class->class_pointer);
- /* Create the garbage collector type memory description */
+ /* Create the garbage collector type memory description. */
__objc_generate_gc_type_description (class);
if (class->super_class)
__objc_send_initialize (class->super_class);
{
- SEL op = sel_register_name ("initialize");
- IMP imp = 0;
- MethodList_t method_list = class->class_pointer->methods;
-
- while (method_list) {
- int i;
- Method_t method;
-
- for (i = 0; i < method_list->method_count; i++) {
- method = &(method_list->method_list[i]);
- if (method->method_name
- && method->method_name->sel_id == op->sel_id) {
- imp = method->method_imp;
- break;
- }
- }
-
- if (imp)
- break;
-
- method_list = method_list->method_next;
-
- }
- if (imp)
- (*imp) ((id) class, op);
-
+ SEL op = sel_registerName ("initialize");
+ struct objc_method *method = search_for_method_in_hierarchy (class->class_pointer,
+ op);
+
+ if (method)
+ {
+ DEBUG_PRINTF (" begin of [%s +initialize]\n", class->name);
+ (*method->method_imp) ((id)class, op);
+ DEBUG_PRINTF (" end of [%s +initialize]\n", class->name);
+ }
+#ifdef DEBUG
+ else
+ {
+ DEBUG_PRINTF (" class '%s' has no +initialize method\n", class->name);
+ }
+#endif
}
}
}
-/* Walk on the methods list of class and install the methods in the reverse
- order of the lists. Since methods added by categories are before the methods
- of class in the methods list, this allows categories to substitute methods
- declared in class. However if more than one category replaces the same
- method nothing is guaranteed about what method will be used.
- Assumes that __objc_runtime_mutex is locked down. */
+/* Walk on the methods list of class and install the methods in the
+ reverse order of the lists. Since methods added by categories are
+ before the methods of class in the methods list, this allows
+ categories to substitute methods declared in class. However if
+ more than one category replaces the same method nothing is
+ guaranteed about what method will be used. Assumes that
+ __objc_runtime_mutex is locked down. */
static void
-__objc_install_methods_in_dtable (Class class, MethodList_t method_list)
+__objc_install_methods_in_dtable (struct sarray *dtable, struct objc_method_list * method_list)
{
int i;
-
+
if (! method_list)
return;
-
+
if (method_list->method_next)
- __objc_install_methods_in_dtable (class, method_list->method_next);
-
+ __objc_install_methods_in_dtable (dtable, method_list->method_next);
+
for (i = 0; i < method_list->method_count; i++)
{
- Method_t method = &(method_list->method_list[i]);
- sarray_at_put_safe (class->dtable,
+ struct objc_method * method = &(method_list->method_list[i]);
+ sarray_at_put_safe (dtable,
(sidx) method->method_name->sel_id,
method->method_imp);
}
}
-/* Assumes that __objc_runtime_mutex is locked down. */
-static void
-__objc_install_dispatch_table_for_class (Class class)
-{
- Class super;
-
- /* If the class has not yet had its class links resolved, we must
- re-compute all class links */
- if (! CLS_ISRESOLV (class))
- __objc_resolve_class_links ();
-
- super = class->super_class;
-
- if (super != 0 && (super->dtable == __objc_uninstalled_dtable))
- __objc_install_dispatch_table_for_class (super);
-
- /* Allocate dtable if necessary */
- if (super == 0)
- {
- objc_mutex_lock (__objc_runtime_mutex);
- class->dtable = sarray_new (__objc_selector_max_index, 0);
- objc_mutex_unlock (__objc_runtime_mutex);
- }
- else
- class->dtable = sarray_lazy_copy (super->dtable);
-
- __objc_install_methods_in_dtable (class, class->methods);
-}
-
void
__objc_update_dispatch_table_for_class (Class class)
{
Class next;
struct sarray *arr;
- /* not yet installed -- skip it */
- if (class->dtable == __objc_uninstalled_dtable)
- return;
+ DEBUG_PRINTF (" _objc_update_dtable_for_class (%s)\n", class->name);
objc_mutex_lock (__objc_runtime_mutex);
+ /* Not yet installed -- skip it unless in +initialize. */
+ if (class->dtable == __objc_uninstalled_dtable)
+ {
+ if (__objc_prepared_dtable_for_class (class))
+ {
+ /* There is a prepared table so we must be initialising this
+ class ... we must re-do the table preparation. */
+ __objc_prepare_dtable_for_class (class);
+ }
+ objc_mutex_unlock (__objc_runtime_mutex);
+ return;
+ }
+
arr = class->dtable;
__objc_install_premature_dtable (class); /* someone might require it... */
sarray_free (arr); /* release memory */
+
+ /* Could have been lazy... */
+ __objc_install_dtable_for_class (class);
- /* could have been lazy... */
- __objc_install_dispatch_table_for_class (class);
-
- if (class->subclass_list) /* Traverse subclasses */
+ if (class->subclass_list) /* Traverse subclasses. */
for (next = class->subclass_list; next; next = next->sibling_class)
__objc_update_dispatch_table_for_class (next);
objc_mutex_unlock (__objc_runtime_mutex);
}
-
/* This function adds a method list to a class. This function is
typically called by another function specific to the run-time. As
such this function does not worry about thread safe issues.
This one is only called for categories. Class objects have their
methods installed right away, and their selectors are made into
- SEL's by the function __objc_register_selectors_from_class. */
+ SEL's by the function __objc_register_selectors_from_class. */
void
-class_add_method_list (Class class, MethodList_t list)
+class_add_method_list (Class class, struct objc_method_list * list)
{
/* Passing of a linked list is not allowed. Do multiple calls. */
assert (! list->method_next);
list->method_next = class->methods;
class->methods = list;
- /* Update the dispatch table of class */
+ /* Update the dispatch table of class. */
__objc_update_dispatch_table_for_class (class);
}
-Method_t
-class_get_instance_method (Class class, SEL op)
+struct objc_method *
+class_getInstanceMethod (Class class_, SEL selector)
{
- return search_for_method_in_hierarchy (class, op);
+ struct objc_method *m;
+
+ if (class_ == Nil || selector == NULL)
+ return NULL;
+
+ m = search_for_method_in_hierarchy (class_, selector);
+ if (m)
+ return m;
+
+ /* Try going through +resolveInstanceMethod:, and do the search
+ again if successful. */
+ if (__objc_resolve_instance_method (class_, selector))
+ return search_for_method_in_hierarchy (class_, selector);
+
+ return NULL;
}
-Method_t
-class_get_class_method (MetaClass class, SEL op)
+struct objc_method *
+class_getClassMethod (Class class_, SEL selector)
{
- return search_for_method_in_hierarchy (class, op);
+ struct objc_method *m;
+
+ if (class_ == Nil || selector == NULL)
+ return NULL;
+
+ m = search_for_method_in_hierarchy (class_->class_pointer,
+ selector);
+ if (m)
+ return m;
+
+ /* Try going through +resolveClassMethod:, and do the search again
+ if successful. */
+ if (__objc_resolve_class_method (class_, selector))
+ return search_for_method_in_hierarchy (class_->class_pointer,
+ selector);
+
+ return NULL;
+}
+
+BOOL
+class_addMethod (Class class_, SEL selector, IMP implementation,
+ const char *method_types)
+{
+ struct objc_method_list *method_list;
+ struct objc_method *method;
+ const char *method_name;
+
+ if (class_ == Nil || selector == NULL || implementation == NULL
+ || method_types == NULL || (strcmp (method_types, "") == 0))
+ return NO;
+
+ method_name = sel_getName (selector);
+ if (method_name == NULL)
+ return NO;
+
+ /* If the method already exists in the class, return NO. It is fine
+ if the method already exists in the superclass; in that case, we
+ are overriding it. */
+ if (CLS_IS_IN_CONSTRUCTION (class_))
+ {
+ /* The class only contains a list of methods; they have not been
+ registered yet, ie, the method_name of each of them is still
+ a string, not a selector. Iterate manually over them to
+ check if we have already added the method. */
+ struct objc_method_list * method_list = class_->methods;
+ while (method_list)
+ {
+ int i;
+
+ /* Search the method list. */
+ for (i = 0; i < method_list->method_count; ++i)
+ {
+ struct objc_method * method = &method_list->method_list[i];
+
+ if (method->method_name
+ && strcmp ((char *)method->method_name, method_name) == 0)
+ return NO;
+ }
+
+ /* The method wasn't found. Follow the link to the next list of
+ methods. */
+ method_list = method_list->method_next;
+ }
+ /* The method wasn't found. It's a new one. Go ahead and add
+ it. */
+ }
+ else
+ {
+ /* Do the standard lookup. This assumes the selectors are
+ mapped. */
+ if (search_for_method_in_list (class_->methods, selector))
+ return NO;
+ }
+
+ method_list = (struct objc_method_list *)objc_calloc (1, sizeof (struct objc_method_list));
+ method_list->method_count = 1;
+
+ method = &(method_list->method_list[0]);
+ method->method_name = objc_malloc (strlen (method_name) + 1);
+ strcpy ((char *)method->method_name, method_name);
+
+ method->method_types = objc_malloc (strlen (method_types) + 1);
+ strcpy ((char *)method->method_types, method_types);
+
+ method->method_imp = implementation;
+
+ if (CLS_IS_IN_CONSTRUCTION (class_))
+ {
+ /* We only need to add the method to the list. It will be
+ registered with the runtime when the class pair is registered
+ (if ever). */
+ method_list->method_next = class_->methods;
+ class_->methods = method_list;
+ }
+ else
+ {
+ /* Add the method to a live class. */
+ objc_mutex_lock (__objc_runtime_mutex);
+ class_add_method_list (class_, method_list);
+ objc_mutex_unlock (__objc_runtime_mutex);
+ }
+
+ return YES;
}
+IMP
+class_replaceMethod (Class class_, SEL selector, IMP implementation,
+ const char *method_types)
+{
+ struct objc_method * method;
+
+ if (class_ == Nil || selector == NULL || implementation == NULL
+ || method_types == NULL)
+ return NULL;
-/* Search for a method starting from the current class up its hierarchy.
- Return a pointer to the method's method structure if found. NULL
- otherwise. */
+ method = search_for_method_in_hierarchy (class_, selector);
+
+ if (method)
+ {
+ return method_setImplementation (method, implementation);
+ }
+ else
+ {
+ class_addMethod (class_, selector, implementation, method_types);
+ return NULL;
+ }
+}
-static Method_t
+/* Search for a method starting from the current class up its
+ hierarchy. Return a pointer to the method's method structure if
+ found. NULL otherwise. */
+static struct objc_method *
search_for_method_in_hierarchy (Class cls, SEL sel)
{
- Method_t method = NULL;
+ struct objc_method * method = NULL;
Class class;
if (! sel_is_mapped (sel))
return NULL;
- /* Scan the method list of the class. If the method isn't found in the
- list then step to its super class. */
+ /* Scan the method list of the class. If the method isn't found in
+ the list then step to its super class. */
for (class = cls; ((! method) && class); class = class->super_class)
method = search_for_method_in_list (class->methods, sel);
-/* Given a linked list of method and a method's name. Search for the named
- method's method structure. Return a pointer to the method's method
- structure if found. NULL otherwise. */
-Method_t
-search_for_method_in_list (MethodList_t list, SEL op)
+/* Given a linked list of method and a method's name. Search for the
+ named method's method structure. Return a pointer to the method's
+ method structure if found. NULL otherwise. */
+struct objc_method *
+search_for_method_in_list (struct objc_method_list * list, SEL op)
{
- MethodList_t method_list = list;
+ struct objc_method_list * method_list = list;
if (! sel_is_mapped (op))
return NULL;
/* Search the method list. */
for (i = 0; i < method_list->method_count; ++i)
{
- Method_t method = &method_list->method_list[i];
+ struct objc_method * method = &method_list->method_list[i];
if (method->method_name)
if (method->method_name->sel_id == op->sel_id)
return NULL;
}
+typedef void * retval_t;
+typedef void * arglist_t;
+
static retval_t __objc_forward (id object, SEL sel, arglist_t args);
-/* Forwarding pointers/integers through the normal registers */
+/* Forwarding pointers/integers through the normal registers. */
static id
__objc_word_forward (id rcv, SEL op, ...)
{
}
/* Specific routine for forwarding floats/double because of
- architectural differences on some processors. i386s for
- example which uses a floating point stack versus general
- registers for floating point numbers. This forward routine
- makes sure that GCC restores the proper return values */
+ architectural differences on some processors. i386s for example
+ which uses a floating point stack versus general registers for
+ floating point numbers. This forward routine makes sure that GCC
+ restores the proper return values. */
static double
__objc_double_forward (id rcv, SEL op, ...)
{
}
-/* This function is installed in the dispatch table for all methods which are
- not implemented. Thus, it is called when a selector is not recognized. */
+/* This function is called for methods which are not implemented,
+ unless a custom forwarding routine has been installed. Please note
+ that most serious users of libobjc (eg, GNUstep base) do install
+ their own forwarding routines, and hence this is never actually
+ used. But, if no custom forwarding routine is installed, this is
+ called when a selector is not recognized. */
static retval_t
__objc_forward (id object, SEL sel, arglist_t args)
{
static SEL frwd_sel = 0; /* !T:SAFE2 */
SEL err_sel;
- /* first try if the object understands forward:: */
+ /* First try if the object understands forward::. */
if (! frwd_sel)
frwd_sel = sel_get_any_uid ("forward::");
if (__objc_responds_to (object, frwd_sel))
{
- imp = get_imp (object->class_pointer, frwd_sel);
+ imp = get_implementation (object, object->class_pointer, frwd_sel);
return (*imp) (object, frwd_sel, sel, args);
}
- /* If the object recognizes the doesNotRecognize: method then we're going
- to send it. */
+ /* If the object recognizes the doesNotRecognize: method then we're
+ going to send it. */
err_sel = sel_get_any_uid ("doesNotRecognize:");
if (__objc_responds_to (object, err_sel))
{
- imp = get_imp (object->class_pointer, err_sel);
+ imp = get_implementation (object, object->class_pointer, err_sel);
return (*imp) (object, err_sel, sel);
}
/* The object doesn't recognize the method. Check for responding to
- error:. If it does then sent it. */
+ error:. If it does then sent it. */
{
- char msg[256 + strlen ((const char *) sel_get_name (sel))
+ char msg[256 + strlen ((const char *) sel_getName (sel))
+ strlen ((const char *) object->class_pointer->name)];
sprintf (msg, "(%s) %s does not recognize %s",
(CLS_ISMETA (object->class_pointer)
? "class"
: "instance" ),
- object->class_pointer->name, sel_get_name (sel));
-
- err_sel = sel_get_any_uid ("error:");
- if (__objc_responds_to (object, err_sel))
- {
- imp = get_imp (object->class_pointer, err_sel);
- return (*imp) (object, sel_get_any_uid ("error:"), msg);
- }
+ object->class_pointer->name, sel_getName (sel));
- /* The object doesn't respond to doesNotRecognize: or error:; Therefore,
- a default action is taken. */
- objc_error (object, OBJC_ERR_UNIMPLEMENTED, "%s\n", msg);
+ /* The object doesn't respond to doesNotRecognize:. Therefore, a
+ default action is taken. */
+ _objc_abort ("%s\n", msg);
return 0;
}
}
void
-__objc_print_dtable_stats ()
+__objc_print_dtable_stats (void)
{
int total = 0;
objc_mutex_unlock (__objc_runtime_mutex);
}
-/* Returns the uninstalled dispatch table indicator.
- If a class' dispatch table points to __objc_uninstalled_dtable
- then that means it needs its dispatch table to be installed. */
-inline
-struct sarray *
-objc_get_uninstalled_dtable ()
+static cache_ptr prepared_dtable_table = 0;
+
+/* This function is called by: objc_msg_lookup, get_imp and
+ __objc_responds_to (and the dispatch table installation functions
+ themselves) to install a dispatch table for a class.
+
+ If CLS is a class, it installs instance methods.
+ If CLS is a meta class, it installs class methods.
+
+ In either case +initialize is invoked for the corresponding class.
+
+ The implementation must insure that the dispatch table is not
+ installed until +initialize completes. Otherwise it opens a
+ potential race since the installation of the dispatch table is used
+ as gate in regular method dispatch and we need to guarantee that
+ +initialize is the first method invoked an that no other thread my
+ dispatch messages to the class before +initialize completes. */
+static void
+__objc_install_dtable_for_class (Class cls)
{
- return __objc_uninstalled_dtable;
+ /* If the class has not yet had its class links resolved, we must
+ re-compute all class links. */
+ if (! CLS_ISRESOLV (cls))
+ __objc_resolve_class_links ();
+
+ /* Make sure the super class has its dispatch table installed or is
+ at least preparing. We do not need to send initialize for the
+ super class since __objc_send_initialize will insure that. */
+ if (cls->super_class
+ && cls->super_class->dtable == __objc_uninstalled_dtable
+ && !__objc_prepared_dtable_for_class (cls->super_class))
+ {
+ __objc_install_dtable_for_class (cls->super_class);
+ /* The superclass initialisation may have also initialised the
+ current class, in which case there is no more to do. */
+ if (cls->dtable != __objc_uninstalled_dtable)
+ return;
+ }
+
+ /* We have already been prepared but +initialize hasn't completed.
+ The +initialize implementation is probably sending 'self'
+ messages. We rely on _objc_get_prepared_imp to retrieve the
+ implementation pointers. */
+ if (__objc_prepared_dtable_for_class (cls))
+ return;
+
+ /* We have this function cache the implementation pointers for
+ _objc_get_prepared_imp but the dispatch table won't be initilized
+ until __objc_send_initialize completes. */
+ __objc_prepare_dtable_for_class (cls);
+
+ /* We may have already invoked +initialize but
+ __objc_update_dispatch_table_for_class invoked by
+ class_add_method_list may have reset dispatch table. */
+
+ /* Call +initialize. If we are a real class, we are installing
+ instance methods. If we are a meta class, we are installing
+ class methods. The __objc_send_initialize itself will insure
+ that the message is called only once per class. */
+ if (CLS_ISCLASS (cls))
+ __objc_send_initialize (cls);
+ else
+ {
+ /* Retrieve the class from the meta class. */
+ Class c = objc_getClass (cls->name);
+ assert (CLS_ISMETA (cls));
+ assert (c);
+ __objc_send_initialize (c);
+ }
+
+ /* We install the dispatch table correctly when +initialize completed. */
+ __objc_install_prepared_dtable_for_class (cls);
+}
+
+/* Builds the dispatch table for the class CLS and stores it in a
+ place where it can be retrieved by __objc_get_prepared_imp until
+ __objc_install_prepared_dtable_for_class installs it into the
+ class. The dispatch table should not be installed into the class
+ until +initialize has completed. */
+static void
+__objc_prepare_dtable_for_class (Class cls)
+{
+ struct sarray *dtable;
+ struct sarray *super_dtable;
+
+ /* This table could be initialized in init.c. We can not use the
+ class name since the class maintains the instance methods and the
+ meta class maintains the the class methods yet both share the
+ same name. Classes should be unique in any program. */
+ if (! prepared_dtable_table)
+ prepared_dtable_table
+ = objc_hash_new (32,
+ (hash_func_type) objc_hash_ptr,
+ (compare_func_type) objc_compare_ptrs);
+
+ /* If the class has not yet had its class links resolved, we must
+ re-compute all class links. */
+ if (! CLS_ISRESOLV (cls))
+ __objc_resolve_class_links ();
+
+ assert (cls);
+ assert (cls->dtable == __objc_uninstalled_dtable);
+
+ /* If there is already a prepared dtable for this class, we must
+ replace it with a new version (since there must have been methods
+ added to or otherwise modified in the class while executing
+ +initialize, and the table needs to be recomputed. */
+ dtable = __objc_prepared_dtable_for_class (cls);
+ if (dtable != 0)
+ {
+ objc_hash_remove (prepared_dtable_table, cls);
+ sarray_free (dtable);
+ }
+
+ /* Now prepare the dtable for population. */
+ assert (cls != cls->super_class);
+ if (cls->super_class)
+ {
+ /* Inherit the method list from the super class. Yet the super
+ class may still be initializing in the case when a class
+ cluster sub class initializes its super classes. */
+ if (cls->super_class->dtable == __objc_uninstalled_dtable)
+ __objc_install_dtable_for_class (cls->super_class);
+
+ super_dtable = cls->super_class->dtable;
+ /* If the dispatch table is not yet installed, we are still in
+ the process of executing +initialize. Yet the dispatch table
+ should be available. */
+ if (super_dtable == __objc_uninstalled_dtable)
+ super_dtable = __objc_prepared_dtable_for_class (cls->super_class);
+
+ assert (super_dtable);
+ dtable = sarray_lazy_copy (super_dtable);
+ }
+ else
+ dtable = sarray_new (__objc_selector_max_index, 0);
+
+ __objc_install_methods_in_dtable (dtable, cls->methods);
+
+ objc_hash_add (&prepared_dtable_table,
+ cls,
+ dtable);
+}
+
+/* This wrapper only exists to allow an easy replacement of the lookup
+ implementation and it is expected that the compiler will optimize
+ it away. */
+static struct sarray *
+__objc_prepared_dtable_for_class (Class cls)
+{
+ struct sarray *dtable = 0;
+ assert (cls);
+ if (prepared_dtable_table)
+ dtable = objc_hash_value_for_key (prepared_dtable_table, cls);
+ /* dtable my be nil, since we call this to check whether we are
+ currently preparing before we start preparing. */
+ return dtable;
+}
+
+/* Helper function for messages sent to CLS or implementation pointers
+ retrieved from CLS during +initialize before the dtable is
+ installed. When a class implicitly initializes another class which
+ in turn implicitly invokes methods in this class, before the
+ implementation of +initialize of CLS completes, this returns the
+ expected implementation. Forwarding remains the responsibility of
+ objc_msg_lookup. This function should only be called under the
+ global lock. */
+static IMP
+__objc_get_prepared_imp (Class cls,SEL sel)
+{
+ struct sarray *dtable;
+ IMP imp;
+
+ assert (cls);
+ assert (sel);
+ assert (cls->dtable == __objc_uninstalled_dtable);
+ dtable = __objc_prepared_dtable_for_class (cls);
+
+ assert (dtable);
+ assert (dtable != __objc_uninstalled_dtable);
+ imp = sarray_get_safe (dtable, (size_t) sel->sel_id);
+
+ /* imp may be Nil if the method does not exist and we may fallback
+ to the forwarding implementation later. */
+ return imp;
+}
+
+/* When this function is called +initialize should be completed. So
+ now we are safe to install the dispatch table for the class so that
+ they become available for other threads that may be waiting in the
+ lock. */
+static void
+__objc_install_prepared_dtable_for_class (Class cls)
+{
+ assert (cls);
+ assert (cls->dtable == __objc_uninstalled_dtable);
+ cls->dtable = __objc_prepared_dtable_for_class (cls);
+
+ assert (cls->dtable);
+ assert (cls->dtable != __objc_uninstalled_dtable);
+ objc_hash_remove (prepared_dtable_table, cls);
}
OSDN Git Service
