1 /* GNU Objective C Runtime message lookup
2 Copyright (C) 1993, 1995, 1996, 1997, 1998,
3 2001, 2002, 2004, 2009, 2010 Free Software Foundation, Inc.
4 Contributed by Kresten Krab Thorup
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under the
9 terms of the GNU General Public License as published by the Free Software
10 Foundation; either version 3, or (at your option) any later version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
26 /* Uncommented the following line to enable debug logging. Use this
27 only while debugging the runtime. */
30 /* FIXME: This file has no business including tm.h. */
31 /* FIXME: This should be using libffi instead of __builtin_apply
34 #include "objc-private/common.h"
35 #include "objc-private/error.h"
37 #include "coretypes.h"
39 #include "objc/runtime.h"
40 #include "objc/message.h" /* For objc_msg_lookup(), objc_msg_lookup_super(). */
42 #include "objc-private/module-abi-8.h"
43 #include "objc-private/runtime.h"
44 #include "objc-private/hash.h"
45 #include "objc-private/sarray.h"
46 #include "objc-private/selector.h" /* For sel_is_mapped() */
47 #include "runtime-info.h"
48 #include <assert.h> /* For assert */
49 #include <string.h> /* For strlen */
51 /* This is how we hack STRUCT_VALUE to be 1 or 0. */
52 #define gen_rtx(args...) 1
53 #define gen_rtx_MEM(args...) 1
54 #define gen_rtx_REG(args...) 1
55 /* Already defined in gcc/coretypes.h. So prevent double definition warning. */
59 #if ! defined (STRUCT_VALUE) || STRUCT_VALUE == 0
60 #define INVISIBLE_STRUCT_RETURN 1
62 #define INVISIBLE_STRUCT_RETURN 0
65 /* The uninstalled dispatch table. */
66 struct sarray
*__objc_uninstalled_dtable
= 0; /* !T:MUTEX */
68 /* Two hooks for method forwarding. If either is set, it is invoked to
69 * return a function that performs the real forwarding. If both are
70 * set, the result of __objc_msg_forward2 will be preferred over that
71 * of __objc_msg_forward. If both return NULL or are unset, the
72 * libgcc based functions (__builtin_apply and friends) are used. */
73 IMP (*__objc_msg_forward
) (SEL
) = NULL
;
74 IMP (*__objc_msg_forward2
) (id
, SEL
) = NULL
;
76 /* Send +initialize to class. */
77 static void __objc_send_initialize (Class
);
79 /* Forward declare some functions */
80 static void __objc_install_dtable_for_class (Class cls
);
81 static void __objc_prepare_dtable_for_class (Class cls
);
82 static void __objc_install_prepared_dtable_for_class (Class cls
);
84 static struct sarray
*__objc_prepared_dtable_for_class (Class cls
);
85 static IMP
__objc_get_prepared_imp (Class cls
,SEL sel
);
88 /* Various forwarding functions that are used based upon the
89 return type for the selector.
90 __objc_block_forward for structures.
91 __objc_double_forward for floats/doubles.
92 __objc_word_forward for pointers or types that fit in registers. */
93 static double __objc_double_forward (id
, SEL
, ...);
94 static id
__objc_word_forward (id
, SEL
, ...);
95 typedef struct { id many
[8]; } __big
;
96 #if INVISIBLE_STRUCT_RETURN
101 __objc_block_forward (id
, SEL
, ...);
102 static struct objc_method
* search_for_method_in_hierarchy (Class
class, SEL sel
);
103 struct objc_method
* search_for_method_in_list (struct objc_method_list
* list
, SEL op
);
104 id
nil_method (id
, SEL
);
106 /* Given a selector, return the proper forwarding implementation. */
109 __objc_get_forward_imp (id rcv
, SEL sel
)
111 /* If a custom forwarding hook was registered, try getting a
112 forwarding function from it. There are two forward routine hooks,
113 one that takes the receiver as an argument and one that does
115 if (__objc_msg_forward2
)
118 if ((result
= __objc_msg_forward2 (rcv
, sel
)) != NULL
)
121 if (__objc_msg_forward
)
124 if ((result
= __objc_msg_forward (sel
)) != NULL
)
128 /* In all other cases, use the default forwarding functions built
129 using __builtin_apply and friends. */
131 const char *t
= sel
->sel_types
;
133 if (t
&& (*t
== '[' || *t
== '(' || *t
== '{')
134 #ifdef OBJC_MAX_STRUCT_BY_VALUE
135 && objc_sizeof_type (t
) > OBJC_MAX_STRUCT_BY_VALUE
138 return (IMP
)__objc_block_forward
;
139 else if (t
&& (*t
== 'f' || *t
== 'd'))
140 return (IMP
)__objc_double_forward
;
142 return (IMP
)__objc_word_forward
;
146 /* Selectors for +resolveClassMethod: and +resolveInstanceMethod:.
147 These are set up at startup. */
148 static SEL selector_resolveClassMethod
= NULL
;
149 static SEL selector_resolveInstanceMethod
= NULL
;
151 /* Internal routines use to resolve a class method using
152 +resolveClassMethod:. 'class' is always a non-Nil class (*not* a
153 meta-class), and 'sel' is the selector that we are trying to
154 resolve. This must be called when class is not Nil, and the
155 dispatch table for class methods has already been installed.
157 This routine tries to call +resolveClassMethod: to give an
158 opportunity to resolve the method. If +resolveClassMethod: returns
159 YES, it tries looking up the method again, and if found, it returns
160 it. Else, it returns NULL. */
163 __objc_resolve_class_method (Class
class, SEL sel
)
165 /* We need to lookup +resolveClassMethod:. */
166 BOOL (*resolveMethodIMP
) (id
, SEL
, SEL
);
168 /* The dispatch table for class methods is already installed and we
169 don't want any forwarding to happen when looking up this method,
170 so we just look it up directly. Note that if 'sel' is precisely
171 +resolveClassMethod:, this would look it up yet again and find
172 nothing. That's no problem and there's no recursion. */
173 resolveMethodIMP
= (BOOL (*) (id
, SEL
, SEL
))sarray_get_safe
174 (class->class_pointer
->dtable
, (size_t) selector_resolveClassMethod
->sel_id
);
176 if (resolveMethodIMP
&& resolveMethodIMP ((id
)class, selector_resolveClassMethod
, sel
))
178 /* +resolveClassMethod: returned YES. Look the method up again.
179 We already know the dtable is installed. */
181 /* TODO: There is the case where +resolveClassMethod: is buggy
182 and returned YES without actually adding the method. We
183 could maybe print an error message. */
184 return sarray_get_safe (class->class_pointer
->dtable
, (size_t) sel
->sel_id
);
190 /* Internal routines use to resolve a instance method using
191 +resolveInstanceMethod:. 'class' is always a non-Nil class, and
192 'sel' is the selector that we are trying to resolve. This must be
193 called when class is not Nil, and the dispatch table for instance
194 methods has already been installed.
196 This routine tries to call +resolveInstanceMethod: to give an
197 opportunity to resolve the method. If +resolveInstanceMethod:
198 returns YES, it tries looking up the method again, and if found, it
199 returns it. Else, it returns NULL. */
202 __objc_resolve_instance_method (Class
class, SEL sel
)
204 /* We need to lookup +resolveInstanceMethod:. */
205 BOOL (*resolveMethodIMP
) (id
, SEL
, SEL
);
207 /* The dispatch table for class methods may not be already installed
208 so we have to install it if needed. */
209 resolveMethodIMP
= sarray_get_safe (class->class_pointer
->dtable
,
210 (size_t) selector_resolveInstanceMethod
->sel_id
);
211 if (resolveMethodIMP
== 0)
213 /* Try again after installing the dtable. */
214 if (class->class_pointer
->dtable
== __objc_uninstalled_dtable
)
216 objc_mutex_lock (__objc_runtime_mutex
);
217 if (class->class_pointer
->dtable
== __objc_uninstalled_dtable
)
218 __objc_install_dtable_for_class (class->class_pointer
);
219 objc_mutex_unlock (__objc_runtime_mutex
);
221 resolveMethodIMP
= sarray_get_safe (class->class_pointer
->dtable
,
222 (size_t) selector_resolveInstanceMethod
->sel_id
);
225 if (resolveMethodIMP
&& resolveMethodIMP ((id
)class, selector_resolveInstanceMethod
, sel
))
227 /* +resolveInstanceMethod: returned YES. Look the method up
228 again. We already know the dtable is installed. */
230 /* TODO: There is the case where +resolveInstanceMethod: is
231 buggy and returned YES without actually adding the method.
232 We could maybe print an error message. */
233 return sarray_get_safe (class->dtable
, (size_t) sel
->sel_id
);
239 /* Given a CLASS and selector, return the implementation corresponding
240 to the method of the selector.
242 If CLASS is a class, the instance method is returned.
243 If CLASS is a meta class, the class method is returned.
245 Since this requires the dispatch table to be installed, this function
246 will implicitly invoke +initialize for CLASS if it hasn't been
247 invoked yet. This also insures that +initialize has been invoked
248 when the returned implementation is called directly.
250 The forwarding hooks require the receiver as an argument (if they are to
251 perform dynamic lookup in proxy objects etc), so this function has a
252 receiver argument to be used with those hooks. */
255 get_implementation (id receiver
, Class
class, SEL sel
)
259 if (class->dtable
== __objc_uninstalled_dtable
)
261 /* The dispatch table needs to be installed. */
262 objc_mutex_lock (__objc_runtime_mutex
);
264 /* Double-checked locking pattern: Check
265 __objc_uninstalled_dtable again in case another thread
266 installed the dtable while we were waiting for the lock to be
268 if (class->dtable
== __objc_uninstalled_dtable
)
269 __objc_install_dtable_for_class (class);
271 /* If the dispatch table is not yet installed, we are still in
272 the process of executing +initialize. But the implementation
273 pointer should be available in the prepared ispatch table if
275 if (class->dtable
== __objc_uninstalled_dtable
)
277 assert (__objc_prepared_dtable_for_class (class) != 0);
278 res
= __objc_get_prepared_imp (class, sel
);
283 objc_mutex_unlock (__objc_runtime_mutex
);
284 /* Call ourselves with the installed dispatch table and get the
287 res
= get_implementation (receiver
, class, sel
);
291 /* The dispatch table has been installed. */
292 res
= sarray_get_safe (class->dtable
, (size_t) sel
->sel_id
);
295 /* The dispatch table has been installed, and the method is
296 not in the dispatch table. So the method just doesn't
297 exist for the class. */
299 /* Try going through the +resolveClassMethod: or
300 +resolveInstanceMethod: process. */
301 if (CLS_ISMETA (class))
303 /* We have the meta class, but we need to invoke the
304 +resolveClassMethod: method on the class. So, we
305 need to obtain the class from the meta class, which
306 we do using the fact that both the class and the
307 meta-class have the same name. */
308 Class realClass
= objc_lookUpClass (class->name
);
310 res
= __objc_resolve_class_method (realClass
, sel
);
313 res
= __objc_resolve_instance_method (class, sel
);
316 res
= __objc_get_forward_imp (receiver
, sel
);
324 get_imp (Class
class, SEL sel
)
326 /* In a vanilla implementation we would first check if the dispatch
327 table is installed. Here instead, to get more speed in the
328 standard case (that the dispatch table is installed) we first try
329 to get the imp using brute force. Only if that fails, we do what
330 we should have been doing from the very beginning, that is, check
331 if the dispatch table needs to be installed, install it if it's
332 not installed, and retrieve the imp from the table if it's
334 void *res
= sarray_get_safe (class->dtable
, (size_t) sel
->sel_id
);
337 res
= get_implementation(nil
, class, sel
);
342 /* The new name of get_imp(). */
344 class_getMethodImplementation (Class class_
, SEL selector
)
346 if (class_
== Nil
|| selector
== NULL
)
349 /* get_imp is inlined, so we're good. */
350 return get_imp (class_
, selector
);
353 /* Given a method, return its implementation. This has been replaced
354 by method_getImplementation() in the modern API. */
356 method_get_imp (struct objc_method
* method
)
358 return (method
!= (struct objc_method
*)0) ? method
->method_imp
: (IMP
)0;
361 /* Query if an object can respond to a selector, returns YES if the
362 object implements the selector otherwise NO. Does not check if the
363 method can be forwarded. Since this requires the dispatch table to
364 installed, this function will implicitly invoke +initialize for the
365 class of OBJECT if it hasn't been invoked yet. */
368 __objc_responds_to (id object
, SEL sel
)
371 struct sarray
*dtable
;
373 /* Install dispatch table if need be */
374 dtable
= object
->class_pointer
->dtable
;
375 if (dtable
== __objc_uninstalled_dtable
)
377 objc_mutex_lock (__objc_runtime_mutex
);
378 if (object
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
379 __objc_install_dtable_for_class (object
->class_pointer
);
381 /* If the dispatch table is not yet installed, we are still in
382 the process of executing +initialize. Yet the dispatch table
383 should be available. */
384 if (object
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
386 dtable
= __objc_prepared_dtable_for_class (object
->class_pointer
);
390 dtable
= object
->class_pointer
->dtable
;
392 objc_mutex_unlock (__objc_runtime_mutex
);
395 /* Get the method from the dispatch table. */
396 res
= sarray_get_safe (dtable
, (size_t) sel
->sel_id
);
397 return (res
!= 0) ? YES
: NO
;
401 class_respondsToSelector (Class class_
, SEL selector
)
403 struct sarray
*dtable
;
406 if (class_
== Nil
|| selector
== NULL
)
409 /* Install dispatch table if need be. */
410 dtable
= class_
->dtable
;
411 if (dtable
== __objc_uninstalled_dtable
)
413 objc_mutex_lock (__objc_runtime_mutex
);
414 if (class_
->dtable
== __objc_uninstalled_dtable
)
415 __objc_install_dtable_for_class (class_
);
417 /* If the dispatch table is not yet installed,
418 we are still in the process of executing +initialize.
419 Yet the dispatch table should be available. */
420 if (class_
->dtable
== __objc_uninstalled_dtable
)
422 dtable
= __objc_prepared_dtable_for_class (class_
);
426 dtable
= class_
->dtable
;
428 objc_mutex_unlock (__objc_runtime_mutex
);
431 /* Get the method from the dispatch table. */
432 res
= sarray_get_safe (dtable
, (size_t) selector
->sel_id
);
433 return (res
!= 0) ? YES
: NO
;
436 /* This is the lookup function. All entries in the table are either a
437 valid method *or* zero. If zero then either the dispatch table
438 needs to be installed or it doesn't exist and forwarding is
441 objc_msg_lookup (id receiver
, SEL op
)
446 /* First try a quick lookup assuming the dispatch table exists. */
447 result
= sarray_get_safe (receiver
->class_pointer
->dtable
,
451 /* Not found ... call get_implementation () to install the
452 dispatch table and call +initialize as required,
453 providing the method implementation or a forwarding
455 result
= get_implementation (receiver
, receiver
->class_pointer
, op
);
460 return (IMP
)nil_method
;
464 objc_msg_lookup_super (struct objc_super
*super
, SEL sel
)
467 return get_imp (super
->super_class
, sel
);
469 return (IMP
)nil_method
;
472 /* Temporarily defined here until objc_msg_sendv() goes away. */
473 char *method_get_first_argument (struct objc_method
*,
476 char *method_get_next_argument (arglist_t argframe
,
478 int method_get_sizeof_arguments (struct objc_method
*);
481 class_get_instance_method (Class
class, SEL op
);
484 objc_msg_sendv (id object
, SEL op
, arglist_t arg_frame
)
486 struct objc_method
*m
= class_get_instance_method (object
->class_pointer
, op
);
488 *((id
*) method_get_first_argument (m
, arg_frame
, &type
)) = object
;
489 *((SEL
*) method_get_next_argument (arg_frame
, &type
)) = op
;
490 return __builtin_apply ((apply_t
) m
->method_imp
,
492 method_get_sizeof_arguments (m
));
496 __objc_init_dispatch_tables ()
498 __objc_uninstalled_dtable
= sarray_new (200, 0);
500 /* TODO: It would be cool to register typed selectors here. */
501 selector_resolveClassMethod
= sel_registerName ("resolveClassMethod:");
502 selector_resolveInstanceMethod
= sel_registerName ("resolveInstanceMethod:");
506 /* Install dummy table for class which causes the first message to
507 that class (or instances hereof) to be initialized properly. */
509 __objc_install_premature_dtable (Class
class)
511 assert (__objc_uninstalled_dtable
);
512 class->dtable
= __objc_uninstalled_dtable
;
515 /* Send +initialize to class if not already done. */
517 __objc_send_initialize (Class
class)
519 /* This *must* be a class object. */
520 assert (CLS_ISCLASS (class));
521 assert (! CLS_ISMETA (class));
523 /* class_add_method_list/__objc_update_dispatch_table_for_class may
524 have reset the dispatch table. The canonical way to insure that
525 we send +initialize just once, is this flag. */
526 if (! CLS_ISINITIALIZED (class))
528 DEBUG_PRINTF ("+initialize: need to initialize class '%s'\n", class->name
);
529 CLS_SETINITIALIZED (class);
530 CLS_SETINITIALIZED (class->class_pointer
);
532 /* Create the garbage collector type memory description. */
533 __objc_generate_gc_type_description (class);
535 if (class->super_class
)
536 __objc_send_initialize (class->super_class
);
539 SEL op
= sel_registerName ("initialize");
541 struct objc_method_list
* method_list
= class->class_pointer
->methods
;
546 struct objc_method
* method
;
548 for (i
= 0; i
< method_list
->method_count
; i
++)
550 method
= &(method_list
->method_list
[i
]);
551 if (method
->method_name
552 && method
->method_name
->sel_id
== op
->sel_id
)
554 imp
= method
->method_imp
;
562 method_list
= method_list
->method_next
;
566 DEBUG_PRINTF (" begin of [%s +initialize]\n", class->name
);
567 (*imp
) ((id
) class, op
);
568 DEBUG_PRINTF (" end of [%s +initialize]\n", class->name
);
573 DEBUG_PRINTF (" class '%s' has no +initialize method\n", class->name
);
580 /* Walk on the methods list of class and install the methods in the
581 reverse order of the lists. Since methods added by categories are
582 before the methods of class in the methods list, this allows
583 categories to substitute methods declared in class. However if
584 more than one category replaces the same method nothing is
585 guaranteed about what method will be used. Assumes that
586 __objc_runtime_mutex is locked down. */
588 __objc_install_methods_in_dtable (struct sarray
*dtable
, struct objc_method_list
* method_list
)
595 if (method_list
->method_next
)
596 __objc_install_methods_in_dtable (dtable
, method_list
->method_next
);
598 for (i
= 0; i
< method_list
->method_count
; i
++)
600 struct objc_method
* method
= &(method_list
->method_list
[i
]);
601 sarray_at_put_safe (dtable
,
602 (sidx
) method
->method_name
->sel_id
,
608 __objc_update_dispatch_table_for_class (Class
class)
613 DEBUG_PRINTF (" _objc_update_dtable_for_class (%s)\n", class->name
);
615 objc_mutex_lock (__objc_runtime_mutex
);
617 /* Not yet installed -- skip it unless in +initialize. */
618 if (class->dtable
== __objc_uninstalled_dtable
)
620 if (__objc_prepared_dtable_for_class (class))
622 /* There is a prepared table so we must be initialising this
623 class ... we must re-do the table preparation. */
624 __objc_prepare_dtable_for_class (class);
626 objc_mutex_unlock (__objc_runtime_mutex
);
631 __objc_install_premature_dtable (class); /* someone might require it... */
632 sarray_free (arr
); /* release memory */
634 /* Could have been lazy... */
635 __objc_install_dtable_for_class (class);
637 if (class->subclass_list
) /* Traverse subclasses. */
638 for (next
= class->subclass_list
; next
; next
= next
->sibling_class
)
639 __objc_update_dispatch_table_for_class (next
);
641 objc_mutex_unlock (__objc_runtime_mutex
);
644 /* This function adds a method list to a class. This function is
645 typically called by another function specific to the run-time. As
646 such this function does not worry about thread safe issues.
648 This one is only called for categories. Class objects have their
649 methods installed right away, and their selectors are made into
650 SEL's by the function __objc_register_selectors_from_class. */
652 class_add_method_list (Class
class, struct objc_method_list
* list
)
654 /* Passing of a linked list is not allowed. Do multiple calls. */
655 assert (! list
->method_next
);
657 __objc_register_selectors_from_list(list
);
659 /* Add the methods to the class's method list. */
660 list
->method_next
= class->methods
;
661 class->methods
= list
;
663 /* Update the dispatch table of class. */
664 __objc_update_dispatch_table_for_class (class);
668 class_get_instance_method (Class
class, SEL op
)
670 return search_for_method_in_hierarchy (class, op
);
674 class_get_class_method (MetaClass
class, SEL op
)
676 return search_for_method_in_hierarchy (class, op
);
680 class_getInstanceMethod (Class class_
, SEL selector
)
682 struct objc_method
*m
;
684 if (class_
== Nil
|| selector
== NULL
)
687 m
= search_for_method_in_hierarchy (class_
, selector
);
691 /* Try going through +resolveInstanceMethod:, and do the search
692 again if successful. */
693 if (__objc_resolve_instance_method (class_
, selector
))
694 return search_for_method_in_hierarchy (class_
, selector
);
700 class_getClassMethod (Class class_
, SEL selector
)
702 struct objc_method
*m
;
704 if (class_
== Nil
|| selector
== NULL
)
707 m
= search_for_method_in_hierarchy (class_
->class_pointer
,
712 /* Try going through +resolveClassMethod:, and do the search again
714 if (__objc_resolve_class_method (class_
, selector
))
715 return search_for_method_in_hierarchy (class_
->class_pointer
,
722 class_addMethod (Class class_
, SEL selector
, IMP implementation
,
723 const char *method_types
)
725 struct objc_method_list
*method_list
;
726 struct objc_method
*method
;
727 const char *method_name
;
729 if (class_
== Nil
|| selector
== NULL
|| implementation
== NULL
730 || method_types
== NULL
|| (strcmp (method_types
, "") == 0))
733 method_name
= sel_getName (selector
);
734 if (method_name
== NULL
)
737 /* If the method already exists in the class, return NO. It is fine
738 if the method already exists in the superclass; in that case, we
739 are overriding it. */
740 if (CLS_IS_IN_CONSTRUCTION (class_
))
742 /* The class only contains a list of methods; they have not been
743 registered yet, ie, the method_name of each of them is still
744 a string, not a selector. Iterate manually over them to
745 check if we have already added the method. */
746 struct objc_method_list
* method_list
= class_
->methods
;
751 /* Search the method list. */
752 for (i
= 0; i
< method_list
->method_count
; ++i
)
754 struct objc_method
* method
= &method_list
->method_list
[i
];
756 if (method
->method_name
757 && strcmp ((char *)method
->method_name
, method_name
) == 0)
761 /* The method wasn't found. Follow the link to the next list of
763 method_list
= method_list
->method_next
;
765 /* The method wasn't found. It's a new one. Go ahead and add
770 /* Do the standard lookup. This assumes the selectors are
772 if (search_for_method_in_list (class_
->methods
, selector
))
776 method_list
= (struct objc_method_list
*)objc_calloc (1, sizeof (struct objc_method_list
));
777 method_list
->method_count
= 1;
779 method
= &(method_list
->method_list
[0]);
780 method
->method_name
= objc_malloc (strlen (method_name
) + 1);
781 strcpy ((char *)method
->method_name
, method_name
);
783 method
->method_types
= objc_malloc (strlen (method_types
) + 1);
784 strcpy ((char *)method
->method_types
, method_types
);
786 method
->method_imp
= implementation
;
788 if (CLS_IS_IN_CONSTRUCTION (class_
))
790 /* We only need to add the method to the list. It will be
791 registered with the runtime when the class pair is registered
793 method_list
->method_next
= class_
->methods
;
794 class_
->methods
= method_list
;
798 /* Add the method to a live class. */
799 objc_mutex_lock (__objc_runtime_mutex
);
800 class_add_method_list (class_
, method_list
);
801 objc_mutex_unlock (__objc_runtime_mutex
);
808 class_replaceMethod (Class class_
, SEL selector
, IMP implementation
,
809 const char *method_types
)
811 struct objc_method
* method
;
813 if (class_
== Nil
|| selector
== NULL
|| implementation
== NULL
814 || method_types
== NULL
)
817 method
= search_for_method_in_hierarchy (class_
, selector
);
821 return method_setImplementation (method
, implementation
);
825 class_addMethod (class_
, selector
, implementation
, method_types
);
830 /* Search for a method starting from the current class up its
831 hierarchy. Return a pointer to the method's method structure if
832 found. NULL otherwise. */
833 static struct objc_method
*
834 search_for_method_in_hierarchy (Class cls
, SEL sel
)
836 struct objc_method
* method
= NULL
;
839 if (! sel_is_mapped (sel
))
842 /* Scan the method list of the class. If the method isn't found in
843 the list then step to its super class. */
844 for (class = cls
; ((! method
) && class); class = class->super_class
)
845 method
= search_for_method_in_list (class->methods
, sel
);
852 /* Given a linked list of method and a method's name. Search for the
853 named method's method structure. Return a pointer to the method's
854 method structure if found. NULL otherwise. */
856 search_for_method_in_list (struct objc_method_list
* list
, SEL op
)
858 struct objc_method_list
* method_list
= list
;
860 if (! sel_is_mapped (op
))
863 /* If not found then we'll search the list. */
868 /* Search the method list. */
869 for (i
= 0; i
< method_list
->method_count
; ++i
)
871 struct objc_method
* method
= &method_list
->method_list
[i
];
873 if (method
->method_name
)
874 if (method
->method_name
->sel_id
== op
->sel_id
)
878 /* The method wasn't found. Follow the link to the next list of
880 method_list
= method_list
->method_next
;
886 static retval_t
__objc_forward (id object
, SEL sel
, arglist_t args
);
888 /* Forwarding pointers/integers through the normal registers. */
890 __objc_word_forward (id rcv
, SEL op
, ...)
894 args
= __builtin_apply_args ();
895 res
= __objc_forward (rcv
, op
, args
);
897 __builtin_return (res
);
902 /* Specific routine for forwarding floats/double because of
903 architectural differences on some processors. i386s for example
904 which uses a floating point stack versus general registers for
905 floating point numbers. This forward routine makes sure that GCC
906 restores the proper return values. */
908 __objc_double_forward (id rcv
, SEL op
, ...)
912 args
= __builtin_apply_args ();
913 res
= __objc_forward (rcv
, op
, args
);
914 __builtin_return (res
);
917 #if INVISIBLE_STRUCT_RETURN
922 __objc_block_forward (id rcv
, SEL op
, ...)
926 args
= __builtin_apply_args ();
927 res
= __objc_forward (rcv
, op
, args
);
929 __builtin_return (res
);
931 #if INVISIBLE_STRUCT_RETURN
932 return (__big
) {{0, 0, 0, 0, 0, 0, 0, 0}};
939 /* This function is installed in the dispatch table for all methods
940 which are not implemented. Thus, it is called when a selector is
943 __objc_forward (id object
, SEL sel
, arglist_t args
)
946 static SEL frwd_sel
= 0; /* !T:SAFE2 */
949 /* First try if the object understands forward::. */
951 frwd_sel
= sel_get_any_uid ("forward::");
953 if (__objc_responds_to (object
, frwd_sel
))
955 imp
= get_implementation (object
, object
->class_pointer
, frwd_sel
);
956 return (*imp
) (object
, frwd_sel
, sel
, args
);
959 /* If the object recognizes the doesNotRecognize: method then we're
961 err_sel
= sel_get_any_uid ("doesNotRecognize:");
962 if (__objc_responds_to (object
, err_sel
))
964 imp
= get_implementation (object
, object
->class_pointer
, err_sel
);
965 return (*imp
) (object
, err_sel
, sel
);
968 /* The object doesn't recognize the method. Check for responding to
969 error:. If it does then sent it. */
971 char msg
[256 + strlen ((const char *) sel_getName (sel
))
972 + strlen ((const char *) object
->class_pointer
->name
)];
974 sprintf (msg
, "(%s) %s does not recognize %s",
975 (CLS_ISMETA (object
->class_pointer
)
978 object
->class_pointer
->name
, sel_getName (sel
));
980 /* TODO: support for error: is surely deprecated ? */
981 err_sel
= sel_get_any_uid ("error:");
982 if (__objc_responds_to (object
, err_sel
))
984 imp
= get_implementation (object
, object
->class_pointer
, err_sel
);
985 return (*imp
) (object
, sel_get_any_uid ("error:"), msg
);
988 /* The object doesn't respond to doesNotRecognize: or error:;
989 Therefore, a default action is taken. */
990 _objc_abort ("%s\n", msg
);
997 __objc_print_dtable_stats (void)
1001 objc_mutex_lock (__objc_runtime_mutex
);
1004 printf ("memory usage: (%s)\n", "2-level sparse arrays");
1006 printf ("memory usage: (%s)\n", "3-level sparse arrays");
1009 printf ("arrays: %d = %ld bytes\n", narrays
,
1010 (long) ((size_t) narrays
* sizeof (struct sarray
)));
1011 total
+= narrays
* sizeof (struct sarray
);
1012 printf ("buckets: %d = %ld bytes\n", nbuckets
,
1013 (long) ((size_t) nbuckets
* sizeof (struct sbucket
)));
1014 total
+= nbuckets
* sizeof (struct sbucket
);
1016 printf ("idxtables: %d = %ld bytes\n",
1017 idxsize
, (long) ((size_t) idxsize
* sizeof (void *)));
1018 total
+= idxsize
* sizeof (void *);
1019 printf ("-----------------------------------\n");
1020 printf ("total: %d bytes\n", total
);
1021 printf ("===================================\n");
1023 objc_mutex_unlock (__objc_runtime_mutex
);
1026 /* Returns the uninstalled dispatch table indicator. If a class'
1027 dispatch table points to __objc_uninstalled_dtable then that means
1028 it needs its dispatch table to be installed. */
1030 objc_get_uninstalled_dtable (void)
1032 return __objc_uninstalled_dtable
;
1035 static cache_ptr prepared_dtable_table
= 0;
1037 /* This function is called by: objc_msg_lookup, get_imp and
1038 __objc_responds_to (and the dispatch table installation functions
1039 themselves) to install a dispatch table for a class.
1041 If CLS is a class, it installs instance methods.
1042 If CLS is a meta class, it installs class methods.
1044 In either case +initialize is invoked for the corresponding class.
1046 The implementation must insure that the dispatch table is not
1047 installed until +initialize completes. Otherwise it opens a
1048 potential race since the installation of the dispatch table is used
1049 as gate in regular method dispatch and we need to guarantee that
1050 +initialize is the first method invoked an that no other thread my
1051 dispatch messages to the class before +initialize completes. */
1053 __objc_install_dtable_for_class (Class cls
)
1055 /* If the class has not yet had its class links resolved, we must
1056 re-compute all class links. */
1057 if (! CLS_ISRESOLV (cls
))
1058 __objc_resolve_class_links ();
1060 /* Make sure the super class has its dispatch table installed or is
1061 at least preparing. We do not need to send initialize for the
1062 super class since __objc_send_initialize will insure that. */
1063 if (cls
->super_class
1064 && cls
->super_class
->dtable
== __objc_uninstalled_dtable
1065 && !__objc_prepared_dtable_for_class (cls
->super_class
))
1067 __objc_install_dtable_for_class (cls
->super_class
);
1068 /* The superclass initialisation may have also initialised the
1069 current class, in which case there is no more to do. */
1070 if (cls
->dtable
!= __objc_uninstalled_dtable
)
1074 /* We have already been prepared but +initialize hasn't completed.
1075 The +initialize implementation is probably sending 'self'
1076 messages. We rely on _objc_get_prepared_imp to retrieve the
1077 implementation pointers. */
1078 if (__objc_prepared_dtable_for_class (cls
))
1081 /* We have this function cache the implementation pointers for
1082 _objc_get_prepared_imp but the dispatch table won't be initilized
1083 until __objc_send_initialize completes. */
1084 __objc_prepare_dtable_for_class (cls
);
1086 /* We may have already invoked +initialize but
1087 __objc_update_dispatch_table_for_class invoked by
1088 class_add_method_list may have reset dispatch table. */
1090 /* Call +initialize. If we are a real class, we are installing
1091 instance methods. If we are a meta class, we are installing
1092 class methods. The __objc_send_initialize itself will insure
1093 that the message is called only once per class. */
1094 if (CLS_ISCLASS (cls
))
1095 __objc_send_initialize (cls
);
1098 /* Retrieve the class from the meta class. */
1099 Class c
= objc_getClass (cls
->name
);
1100 assert (CLS_ISMETA (cls
));
1102 __objc_send_initialize (c
);
1105 /* We install the dispatch table correctly when +initialize completed. */
1106 __objc_install_prepared_dtable_for_class (cls
);
1109 /* Builds the dispatch table for the class CLS and stores it in a
1110 place where it can be retrieved by __objc_get_prepared_imp until
1111 __objc_install_prepared_dtable_for_class installs it into the
1112 class. The dispatch table should not be installed into the class
1113 until +initialize has completed. */
1115 __objc_prepare_dtable_for_class (Class cls
)
1117 struct sarray
*dtable
;
1118 struct sarray
*super_dtable
;
1120 /* This table could be initialized in init.c. We can not use the
1121 class name since the class maintains the instance methods and the
1122 meta class maintains the the class methods yet both share the
1123 same name. Classes should be unique in any program. */
1124 if (! prepared_dtable_table
)
1125 prepared_dtable_table
1126 = objc_hash_new (32,
1127 (hash_func_type
) objc_hash_ptr
,
1128 (compare_func_type
) objc_compare_ptrs
);
1130 /* If the class has not yet had its class links resolved, we must
1131 re-compute all class links. */
1132 if (! CLS_ISRESOLV (cls
))
1133 __objc_resolve_class_links ();
1136 assert (cls
->dtable
== __objc_uninstalled_dtable
);
1138 /* If there is already a prepared dtable for this class, we must
1139 replace it with a new version (since there must have been methods
1140 added to or otherwise modified in the class while executing
1141 +initialize, and the table needs to be recomputed. */
1142 dtable
= __objc_prepared_dtable_for_class (cls
);
1145 objc_hash_remove (prepared_dtable_table
, cls
);
1146 sarray_free (dtable
);
1149 /* Now prepare the dtable for population. */
1150 assert (cls
!= cls
->super_class
);
1151 if (cls
->super_class
)
1153 /* Inherit the method list from the super class. Yet the super
1154 class may still be initializing in the case when a class
1155 cluster sub class initializes its super classes. */
1156 if (cls
->super_class
->dtable
== __objc_uninstalled_dtable
)
1157 __objc_install_dtable_for_class (cls
->super_class
);
1159 super_dtable
= cls
->super_class
->dtable
;
1160 /* If the dispatch table is not yet installed, we are still in
1161 the process of executing +initialize. Yet the dispatch table
1162 should be available. */
1163 if (super_dtable
== __objc_uninstalled_dtable
)
1164 super_dtable
= __objc_prepared_dtable_for_class (cls
->super_class
);
1166 assert (super_dtable
);
1167 dtable
= sarray_lazy_copy (super_dtable
);
1170 dtable
= sarray_new (__objc_selector_max_index
, 0);
1172 __objc_install_methods_in_dtable (dtable
, cls
->methods
);
1174 objc_hash_add (&prepared_dtable_table
,
1179 /* This wrapper only exists to allow an easy replacement of the lookup
1180 implementation and it is expected that the compiler will optimize
1182 static struct sarray
*
1183 __objc_prepared_dtable_for_class (Class cls
)
1185 struct sarray
*dtable
= 0;
1187 if (prepared_dtable_table
)
1188 dtable
= objc_hash_value_for_key (prepared_dtable_table
, cls
);
1189 /* dtable my be nil, since we call this to check whether we are
1190 currently preparing before we start preparing. */
1194 /* Helper function for messages sent to CLS or implementation pointers
1195 retrieved from CLS during +initialize before the dtable is
1196 installed. When a class implicitly initializes another class which
1197 in turn implicitly invokes methods in this class, before the
1198 implementation of +initialize of CLS completes, this returns the
1199 expected implementation. Forwarding remains the responsibility of
1200 objc_msg_lookup. This function should only be called under the
1203 __objc_get_prepared_imp (Class cls
,SEL sel
)
1205 struct sarray
*dtable
;
1210 assert (cls
->dtable
== __objc_uninstalled_dtable
);
1211 dtable
= __objc_prepared_dtable_for_class (cls
);
1214 assert (dtable
!= __objc_uninstalled_dtable
);
1215 imp
= sarray_get_safe (dtable
, (size_t) sel
->sel_id
);
1217 /* imp may be Nil if the method does not exist and we may fallback
1218 to the forwarding implementation later. */
1222 /* When this function is called +initialize should be completed. So
1223 now we are safe to install the dispatch table for the class so that
1224 they become available for other threads that may be waiting in the
1227 __objc_install_prepared_dtable_for_class (Class cls
)
1230 assert (cls
->dtable
== __objc_uninstalled_dtable
);
1231 cls
->dtable
= __objc_prepared_dtable_for_class (cls
);
1233 assert (cls
->dtable
);
1234 assert (cls
->dtable
!= __objc_uninstalled_dtable
);
1235 objc_hash_remove (prepared_dtable_table
, cls
);