1 /* GNU Objective C Runtime message lookup
2 Copyright (C) 1993, 1995, 1996, 1997, 1998,
3 2001, 2002, 2004 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 2, 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 You should have received a copy of the GNU General Public License along with
18 GCC; see the file COPYING. If not, write to the Free Software
19 Foundation, 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
22 /* As a special exception, if you link this library with files compiled with
23 GCC to produce an executable, this does not cause the resulting executable
24 to be covered by the GNU General Public License. This exception does not
25 however invalidate any other reasons why the executable file might be
26 covered by the GNU General Public License. */
28 /* FIXME: This file has no business including tm.h. */
29 /* FIXME: This should be using libffi instead of __builtin_apply
33 #include "coretypes.h"
35 #include "objc/runtime.h"
36 #include "objc/sarray.h"
37 #include "objc/encoding.h"
38 #include "runtime-info.h"
40 /* This is how we hack STRUCT_VALUE to be 1 or 0. */
41 #define gen_rtx(args...) 1
42 #define gen_rtx_MEM(args...) 1
43 #define gen_rtx_REG(args...) 1
46 #if ! defined (STRUCT_VALUE) || STRUCT_VALUE == 0
47 #define INVISIBLE_STRUCT_RETURN 1
49 #define INVISIBLE_STRUCT_RETURN 0
52 /* The uninstalled dispatch table */
53 struct sarray
*__objc_uninstalled_dtable
= 0; /* !T:MUTEX */
55 /* Two hooks for method forwarding. If either is set, it is invoked
56 * to return a function that performs the real forwarding. If both
57 * are set, the result of __objc_msg_forward2 will be preferred over
58 * that of __objc_msg_forward. If both return NULL or are unset,
59 * the libgcc based functions (__builtin_apply and friends) are
62 IMP (*__objc_msg_forward
) (SEL
) = NULL
;
63 IMP (*__objc_msg_forward2
) (id
, SEL
) = NULL
;
65 /* Send +initialize to class */
66 static void __objc_send_initialize (Class
);
68 static void __objc_install_dispatch_table_for_class (Class
);
70 /* Forward declare some functions */
71 static void __objc_init_install_dtable (id
, SEL
);
73 /* Various forwarding functions that are used based upon the
74 return type for the selector.
75 __objc_block_forward for structures.
76 __objc_double_forward for floats/doubles.
77 __objc_word_forward for pointers or types that fit in registers. */
78 static double __objc_double_forward (id
, SEL
, ...);
79 static id
__objc_word_forward (id
, SEL
, ...);
80 typedef struct { id many
[8]; } __big
;
81 #if INVISIBLE_STRUCT_RETURN
86 __objc_block_forward (id
, SEL
, ...);
87 static Method_t
search_for_method_in_hierarchy (Class
class, SEL sel
);
88 Method_t
search_for_method_in_list (MethodList_t list
, SEL op
);
89 id
nil_method (id
, SEL
);
91 /* Given a selector, return the proper forwarding implementation. */
94 __objc_get_forward_imp (id rcv
, SEL sel
)
96 /* If a custom forwarding hook was registered, try getting a forwarding
97 function from it. There are two forward routine hooks, one that
98 takes the receiver as an argument and one that does not. */
99 if (__objc_msg_forward2
)
102 if ((result
= __objc_msg_forward2 (rcv
, sel
)) != NULL
)
105 if (__objc_msg_forward
)
108 if ((result
= __objc_msg_forward (sel
)) != NULL
)
112 /* In all other cases, use the default forwarding functions built using
113 __builtin_apply and friends. */
115 const char *t
= sel
->sel_types
;
117 if (t
&& (*t
== '[' || *t
== '(' || *t
== '{')
118 #ifdef OBJC_MAX_STRUCT_BY_VALUE
119 && objc_sizeof_type (t
) > OBJC_MAX_STRUCT_BY_VALUE
122 return (IMP
)__objc_block_forward
;
123 else if (t
&& (*t
== 'f' || *t
== 'd'))
124 return (IMP
)__objc_double_forward
;
126 return (IMP
)__objc_word_forward
;
130 /* Given a class and selector, return the selector's implementation. */
133 get_imp (Class
class, SEL sel
)
135 /* In a vanilla implementation we would first check if the dispatch
136 table is installed. Here instead, to get more speed in the
137 standard case (that the dispatch table is installed) we first try
138 to get the imp using brute force. Only if that fails, we do what
139 we should have been doing from the very beginning, that is, check
140 if the dispatch table needs to be installed, install it if it's
141 not installed, and retrieve the imp from the table if it's
143 void *res
= sarray_get_safe (class->dtable
, (size_t) sel
->sel_id
);
146 /* Not a valid method */
147 if (class->dtable
== __objc_uninstalled_dtable
)
149 /* The dispatch table needs to be installed. */
150 objc_mutex_lock (__objc_runtime_mutex
);
152 /* Double-checked locking pattern: Check
153 __objc_uninstalled_dtable again in case another thread
154 installed the dtable while we were waiting for the lock
156 if (class->dtable
== __objc_uninstalled_dtable
)
158 __objc_install_dispatch_table_for_class (class);
161 objc_mutex_unlock (__objc_runtime_mutex
);
162 /* Call ourselves with the installed dispatch table
163 and get the real method */
164 res
= get_imp (class, sel
);
168 /* The dispatch table has been installed. */
170 /* Get the method from the dispatch table (we try to get it
171 again in case another thread has installed the dtable just
172 after we invoked sarray_get_safe, but before we checked
173 class->dtable == __objc_uninstalled_dtable).
175 res
= sarray_get_safe (class->dtable
, (size_t) sel
->sel_id
);
178 /* The dispatch table has been installed, and the method
179 is not in the dispatch table. So the method just
180 doesn't exist for the class. Return the forwarding
182 res
= __objc_get_forward_imp ((id
)class, sel
);
189 /* Query if an object can respond to a selector, returns YES if the
190 object implements the selector otherwise NO. Does not check if the
191 method can be forwarded. */
194 __objc_responds_to (id object
, SEL sel
)
198 /* Install dispatch table if need be */
199 if (object
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
201 objc_mutex_lock (__objc_runtime_mutex
);
202 if (object
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
204 __objc_install_dispatch_table_for_class (object
->class_pointer
);
206 objc_mutex_unlock (__objc_runtime_mutex
);
209 /* Get the method from the dispatch table */
210 res
= sarray_get_safe (object
->class_pointer
->dtable
, (size_t) sel
->sel_id
);
214 /* This is the lookup function. All entries in the table are either a
215 valid method *or* zero. If zero then either the dispatch table
216 needs to be installed or it doesn't exist and forwarding is attempted. */
219 objc_msg_lookup (id receiver
, SEL op
)
224 result
= sarray_get_safe (receiver
->class_pointer
->dtable
,
228 /* Not a valid method */
229 if (receiver
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
231 /* The dispatch table needs to be installed.
232 This happens on the very first method call to the class. */
233 __objc_init_install_dtable (receiver
, op
);
235 /* Get real method for this in newly installed dtable */
236 result
= get_imp (receiver
->class_pointer
, op
);
240 /* The dispatch table has been installed. Check again
241 if the method exists (just in case the dispatch table
242 has been installed by another thread after we did the
243 previous check that the method exists).
245 result
= sarray_get_safe (receiver
->class_pointer
->dtable
,
249 /* If the method still just doesn't exist for the
250 class, attempt to forward the method. */
251 result
= __objc_get_forward_imp (receiver
, op
);
258 return (IMP
)nil_method
;
262 objc_msg_lookup_super (Super_t super
, SEL sel
)
265 return get_imp (super
->class, sel
);
267 return (IMP
)nil_method
;
270 int method_get_sizeof_arguments (Method
*);
273 objc_msg_sendv (id object
, SEL op
, arglist_t arg_frame
)
275 Method
*m
= class_get_instance_method (object
->class_pointer
, op
);
277 *((id
*) method_get_first_argument (m
, arg_frame
, &type
)) = object
;
278 *((SEL
*) method_get_next_argument (arg_frame
, &type
)) = op
;
279 return __builtin_apply ((apply_t
) m
->method_imp
,
281 method_get_sizeof_arguments (m
));
285 __objc_init_dispatch_tables ()
287 __objc_uninstalled_dtable
= sarray_new (200, 0);
290 /* This function is called by objc_msg_lookup when the
291 dispatch table needs to be installed; thus it is called once
292 for each class, namely when the very first message is sent to it. */
294 __objc_init_install_dtable (id receiver
, SEL op
__attribute__ ((__unused__
)))
296 objc_mutex_lock (__objc_runtime_mutex
);
298 /* This may happen, if the programmer has taken the address of a
299 method before the dtable was initialized... too bad for him! */
300 if (receiver
->class_pointer
->dtable
!= __objc_uninstalled_dtable
)
302 objc_mutex_unlock (__objc_runtime_mutex
);
306 if (CLS_ISCLASS (receiver
->class_pointer
))
308 /* receiver is an ordinary object */
309 assert (CLS_ISCLASS (receiver
->class_pointer
));
311 /* install instance methods table */
312 __objc_install_dispatch_table_for_class (receiver
->class_pointer
);
314 /* call +initialize -- this will in turn install the factory
315 dispatch table if not already done :-) */
316 __objc_send_initialize (receiver
->class_pointer
);
320 /* receiver is a class object */
321 assert (CLS_ISCLASS ((Class
)receiver
));
322 assert (CLS_ISMETA (receiver
->class_pointer
));
324 /* Install real dtable for factory methods */
325 __objc_install_dispatch_table_for_class (receiver
->class_pointer
);
327 __objc_send_initialize ((Class
)receiver
);
329 objc_mutex_unlock (__objc_runtime_mutex
);
332 /* Install dummy table for class which causes the first message to
333 that class (or instances hereof) to be initialized properly */
335 __objc_install_premature_dtable (Class
class)
337 assert (__objc_uninstalled_dtable
);
338 class->dtable
= __objc_uninstalled_dtable
;
341 /* Send +initialize to class if not already done */
343 __objc_send_initialize (Class
class)
345 /* This *must* be a class object */
346 assert (CLS_ISCLASS (class));
347 assert (! CLS_ISMETA (class));
349 if (! CLS_ISINITIALIZED (class))
351 CLS_SETINITIALIZED (class);
352 CLS_SETINITIALIZED (class->class_pointer
);
354 /* Create the garbage collector type memory description */
355 __objc_generate_gc_type_description (class);
357 if (class->super_class
)
358 __objc_send_initialize (class->super_class
);
361 SEL op
= sel_register_name ("initialize");
363 MethodList_t method_list
= class->class_pointer
->methods
;
365 while (method_list
) {
369 for (i
= 0; i
< method_list
->method_count
; i
++) {
370 method
= &(method_list
->method_list
[i
]);
371 if (method
->method_name
372 && method
->method_name
->sel_id
== op
->sel_id
) {
373 imp
= method
->method_imp
;
381 method_list
= method_list
->method_next
;
385 (*imp
) ((id
) class, op
);
391 /* Walk on the methods list of class and install the methods in the reverse
392 order of the lists. Since methods added by categories are before the methods
393 of class in the methods list, this allows categories to substitute methods
394 declared in class. However if more than one category replaces the same
395 method nothing is guaranteed about what method will be used.
396 Assumes that __objc_runtime_mutex is locked down. */
398 __objc_install_methods_in_dtable (Class
class, MethodList_t method_list
)
405 if (method_list
->method_next
)
406 __objc_install_methods_in_dtable (class, method_list
->method_next
);
408 for (i
= 0; i
< method_list
->method_count
; i
++)
410 Method_t method
= &(method_list
->method_list
[i
]);
411 sarray_at_put_safe (class->dtable
,
412 (sidx
) method
->method_name
->sel_id
,
417 /* Assumes that __objc_runtime_mutex is locked down. */
419 __objc_install_dispatch_table_for_class (Class
class)
423 /* If the class has not yet had its class links resolved, we must
424 re-compute all class links */
425 if (! CLS_ISRESOLV (class))
426 __objc_resolve_class_links ();
428 super
= class->super_class
;
430 if (super
!= 0 && (super
->dtable
== __objc_uninstalled_dtable
))
431 __objc_install_dispatch_table_for_class (super
);
433 /* Allocate dtable if necessary */
436 objc_mutex_lock (__objc_runtime_mutex
);
437 class->dtable
= sarray_new (__objc_selector_max_index
, 0);
438 objc_mutex_unlock (__objc_runtime_mutex
);
441 class->dtable
= sarray_lazy_copy (super
->dtable
);
443 __objc_install_methods_in_dtable (class, class->methods
);
447 __objc_update_dispatch_table_for_class (Class
class)
452 /* not yet installed -- skip it */
453 if (class->dtable
== __objc_uninstalled_dtable
)
456 objc_mutex_lock (__objc_runtime_mutex
);
459 __objc_install_premature_dtable (class); /* someone might require it... */
460 sarray_free (arr
); /* release memory */
462 /* could have been lazy... */
463 __objc_install_dispatch_table_for_class (class);
465 if (class->subclass_list
) /* Traverse subclasses */
466 for (next
= class->subclass_list
; next
; next
= next
->sibling_class
)
467 __objc_update_dispatch_table_for_class (next
);
469 objc_mutex_unlock (__objc_runtime_mutex
);
473 /* This function adds a method list to a class. This function is
474 typically called by another function specific to the run-time. As
475 such this function does not worry about thread safe issues.
477 This one is only called for categories. Class objects have their
478 methods installed right away, and their selectors are made into
479 SEL's by the function __objc_register_selectors_from_class. */
481 class_add_method_list (Class
class, MethodList_t list
)
483 /* Passing of a linked list is not allowed. Do multiple calls. */
484 assert (! list
->method_next
);
486 __objc_register_selectors_from_list(list
);
488 /* Add the methods to the class's method list. */
489 list
->method_next
= class->methods
;
490 class->methods
= list
;
492 /* Update the dispatch table of class */
493 __objc_update_dispatch_table_for_class (class);
497 class_get_instance_method (Class
class, SEL op
)
499 return search_for_method_in_hierarchy (class, op
);
503 class_get_class_method (MetaClass
class, SEL op
)
505 return search_for_method_in_hierarchy (class, op
);
509 /* Search for a method starting from the current class up its hierarchy.
510 Return a pointer to the method's method structure if found. NULL
514 search_for_method_in_hierarchy (Class cls
, SEL sel
)
516 Method_t method
= NULL
;
519 if (! sel_is_mapped (sel
))
522 /* Scan the method list of the class. If the method isn't found in the
523 list then step to its super class. */
524 for (class = cls
; ((! method
) && class); class = class->super_class
)
525 method
= search_for_method_in_list (class->methods
, sel
);
532 /* Given a linked list of method and a method's name. Search for the named
533 method's method structure. Return a pointer to the method's method
534 structure if found. NULL otherwise. */
536 search_for_method_in_list (MethodList_t list
, SEL op
)
538 MethodList_t method_list
= list
;
540 if (! sel_is_mapped (op
))
543 /* If not found then we'll search the list. */
548 /* Search the method list. */
549 for (i
= 0; i
< method_list
->method_count
; ++i
)
551 Method_t method
= &method_list
->method_list
[i
];
553 if (method
->method_name
)
554 if (method
->method_name
->sel_id
== op
->sel_id
)
558 /* The method wasn't found. Follow the link to the next list of
560 method_list
= method_list
->method_next
;
566 static retval_t
__objc_forward (id object
, SEL sel
, arglist_t args
);
568 /* Forwarding pointers/integers through the normal registers */
570 __objc_word_forward (id rcv
, SEL op
, ...)
574 args
= __builtin_apply_args ();
575 res
= __objc_forward (rcv
, op
, args
);
577 __builtin_return (res
);
582 /* Specific routine for forwarding floats/double because of
583 architectural differences on some processors. i386s for
584 example which uses a floating point stack versus general
585 registers for floating point numbers. This forward routine
586 makes sure that GCC restores the proper return values */
588 __objc_double_forward (id rcv
, SEL op
, ...)
592 args
= __builtin_apply_args ();
593 res
= __objc_forward (rcv
, op
, args
);
594 __builtin_return (res
);
597 #if INVISIBLE_STRUCT_RETURN
602 __objc_block_forward (id rcv
, SEL op
, ...)
606 args
= __builtin_apply_args ();
607 res
= __objc_forward (rcv
, op
, args
);
609 __builtin_return (res
);
611 #if INVISIBLE_STRUCT_RETURN
612 return (__big
) {{0, 0, 0, 0, 0, 0, 0, 0}};
619 /* This function is installed in the dispatch table for all methods which are
620 not implemented. Thus, it is called when a selector is not recognized. */
622 __objc_forward (id object
, SEL sel
, arglist_t args
)
625 static SEL frwd_sel
= 0; /* !T:SAFE2 */
628 /* first try if the object understands forward:: */
630 frwd_sel
= sel_get_any_uid ("forward::");
632 if (__objc_responds_to (object
, frwd_sel
))
634 imp
= get_imp (object
->class_pointer
, frwd_sel
);
635 return (*imp
) (object
, frwd_sel
, sel
, args
);
638 /* If the object recognizes the doesNotRecognize: method then we're going
640 err_sel
= sel_get_any_uid ("doesNotRecognize:");
641 if (__objc_responds_to (object
, err_sel
))
643 imp
= get_imp (object
->class_pointer
, err_sel
);
644 return (*imp
) (object
, err_sel
, sel
);
647 /* The object doesn't recognize the method. Check for responding to
648 error:. If it does then sent it. */
650 char msg
[256 + strlen ((const char *) sel_get_name (sel
))
651 + strlen ((const char *) object
->class_pointer
->name
)];
653 sprintf (msg
, "(%s) %s does not recognize %s",
654 (CLS_ISMETA (object
->class_pointer
)
657 object
->class_pointer
->name
, sel_get_name (sel
));
659 err_sel
= sel_get_any_uid ("error:");
660 if (__objc_responds_to (object
, err_sel
))
662 imp
= get_imp (object
->class_pointer
, err_sel
);
663 return (*imp
) (object
, sel_get_any_uid ("error:"), msg
);
666 /* The object doesn't respond to doesNotRecognize: or error:; Therefore,
667 a default action is taken. */
668 objc_error (object
, OBJC_ERR_UNIMPLEMENTED
, "%s\n", msg
);
675 __objc_print_dtable_stats ()
679 objc_mutex_lock (__objc_runtime_mutex
);
682 printf ("memory usage: (%s)\n", "2-level sparse arrays");
684 printf ("memory usage: (%s)\n", "3-level sparse arrays");
687 printf ("arrays: %d = %ld bytes\n", narrays
,
688 (long) narrays
* sizeof (struct sarray
));
689 total
+= narrays
* sizeof (struct sarray
);
690 printf ("buckets: %d = %ld bytes\n", nbuckets
,
691 (long) nbuckets
* sizeof (struct sbucket
));
692 total
+= nbuckets
* sizeof (struct sbucket
);
694 printf ("idxtables: %d = %ld bytes\n",
695 idxsize
, (long) idxsize
* sizeof (void *));
696 total
+= idxsize
* sizeof (void *);
697 printf ("-----------------------------------\n");
698 printf ("total: %d bytes\n", total
);
699 printf ("===================================\n");
701 objc_mutex_unlock (__objc_runtime_mutex
);
704 /* Returns the uninstalled dispatch table indicator.
705 If a class' dispatch table points to __objc_uninstalled_dtable
706 then that means it needs its dispatch table to be installed. */
709 objc_get_uninstalled_dtable ()
711 return __objc_uninstalled_dtable
;