1 /* GNU Objective C Runtime message lookup
2 Copyright (C) 1993, 1995, 1996, 1997, 1998,
3 2001, 2002, 2004, 2009 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/>. */
27 /* FIXME: This file has no business including tm.h. */
28 /* FIXME: This should be using libffi instead of __builtin_apply
31 #include "objc-private/common.h"
32 #include "objc-private/error.h"
34 #include "coretypes.h"
36 #include "objc/objc-api.h"
38 #include "objc-private/runtime.h"
39 #include "objc-private/sarray.h"
40 #include "objc/encoding.h"
41 #include "runtime-info.h"
42 #include <assert.h> /* For assert */
43 #include <string.h> /* For strlen */
45 /* This is how we hack STRUCT_VALUE to be 1 or 0. */
46 #define gen_rtx(args...) 1
47 #define gen_rtx_MEM(args...) 1
48 #define gen_rtx_REG(args...) 1
49 /* Alread defined in gcc/coretypes.h. So prevent double definition warning. */
53 #if ! defined (STRUCT_VALUE) || STRUCT_VALUE == 0
54 #define INVISIBLE_STRUCT_RETURN 1
56 #define INVISIBLE_STRUCT_RETURN 0
59 /* The uninstalled dispatch table */
60 struct sarray
*__objc_uninstalled_dtable
= 0; /* !T:MUTEX */
62 /* Two hooks for method forwarding. If either is set, it is invoked
63 * to return a function that performs the real forwarding. If both
64 * are set, the result of __objc_msg_forward2 will be preferred over
65 * that of __objc_msg_forward. If both return NULL or are unset,
66 * the libgcc based functions (__builtin_apply and friends) are
69 IMP (*__objc_msg_forward
) (SEL
) = NULL
;
70 IMP (*__objc_msg_forward2
) (id
, SEL
) = NULL
;
72 /* Send +initialize to class */
73 static void __objc_send_initialize (Class
);
75 static void __objc_install_dispatch_table_for_class (Class
);
77 /* Forward declare some functions */
78 static void __objc_init_install_dtable (id
, SEL
);
80 /* Various forwarding functions that are used based upon the
81 return type for the selector.
82 __objc_block_forward for structures.
83 __objc_double_forward for floats/doubles.
84 __objc_word_forward for pointers or types that fit in registers. */
85 static double __objc_double_forward (id
, SEL
, ...);
86 static id
__objc_word_forward (id
, SEL
, ...);
87 typedef struct { id many
[8]; } __big
;
88 #if INVISIBLE_STRUCT_RETURN
93 __objc_block_forward (id
, SEL
, ...);
94 static Method_t
search_for_method_in_hierarchy (Class
class, SEL sel
);
95 Method_t
search_for_method_in_list (MethodList_t list
, SEL op
);
96 id
nil_method (id
, SEL
);
98 /* Given a selector, return the proper forwarding implementation. */
101 __objc_get_forward_imp (id rcv
, SEL sel
)
103 /* If a custom forwarding hook was registered, try getting a forwarding
104 function from it. There are two forward routine hooks, one that
105 takes the receiver as an argument and one that does not. */
106 if (__objc_msg_forward2
)
109 if ((result
= __objc_msg_forward2 (rcv
, sel
)) != NULL
)
112 if (__objc_msg_forward
)
115 if ((result
= __objc_msg_forward (sel
)) != NULL
)
119 /* In all other cases, use the default forwarding functions built using
120 __builtin_apply and friends. */
122 const char *t
= sel
->sel_types
;
124 if (t
&& (*t
== '[' || *t
== '(' || *t
== '{')
125 #ifdef OBJC_MAX_STRUCT_BY_VALUE
126 && objc_sizeof_type (t
) > OBJC_MAX_STRUCT_BY_VALUE
129 return (IMP
)__objc_block_forward
;
130 else if (t
&& (*t
== 'f' || *t
== 'd'))
131 return (IMP
)__objc_double_forward
;
133 return (IMP
)__objc_word_forward
;
137 /* Given a class and selector, return the selector's implementation. */
140 get_imp (Class
class, SEL sel
)
142 /* In a vanilla implementation we would first check if the dispatch
143 table is installed. Here instead, to get more speed in the
144 standard case (that the dispatch table is installed) we first try
145 to get the imp using brute force. Only if that fails, we do what
146 we should have been doing from the very beginning, that is, check
147 if the dispatch table needs to be installed, install it if it's
148 not installed, and retrieve the imp from the table if it's
150 void *res
= sarray_get_safe (class->dtable
, (size_t) sel
->sel_id
);
153 /* Not a valid method */
154 if (class->dtable
== __objc_uninstalled_dtable
)
156 /* The dispatch table needs to be installed. */
157 objc_mutex_lock (__objc_runtime_mutex
);
159 /* Double-checked locking pattern: Check
160 __objc_uninstalled_dtable again in case another thread
161 installed the dtable while we were waiting for the lock
163 if (class->dtable
== __objc_uninstalled_dtable
)
165 __objc_install_dispatch_table_for_class (class);
168 objc_mutex_unlock (__objc_runtime_mutex
);
169 /* Call ourselves with the installed dispatch table
170 and get the real method */
171 res
= get_imp (class, sel
);
175 /* The dispatch table has been installed. */
177 /* Get the method from the dispatch table (we try to get it
178 again in case another thread has installed the dtable just
179 after we invoked sarray_get_safe, but before we checked
180 class->dtable == __objc_uninstalled_dtable).
182 res
= sarray_get_safe (class->dtable
, (size_t) sel
->sel_id
);
185 /* The dispatch table has been installed, and the method
186 is not in the dispatch table. So the method just
187 doesn't exist for the class. Return the forwarding
189 res
= __objc_get_forward_imp ((id
)class, sel
);
196 /* Given a method, return its implementation. */
198 method_get_imp (Method_t method
)
200 return (method
!= (Method_t
)0) ? method
->method_imp
: (IMP
)0;
203 /* Query if an object can respond to a selector, returns YES if the
204 object implements the selector otherwise NO. Does not check if the
205 method can be forwarded. */
208 __objc_responds_to (id object
, SEL sel
)
212 /* Install dispatch table if need be */
213 if (object
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
215 objc_mutex_lock (__objc_runtime_mutex
);
216 if (object
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
218 __objc_install_dispatch_table_for_class (object
->class_pointer
);
220 objc_mutex_unlock (__objc_runtime_mutex
);
223 /* Get the method from the dispatch table */
224 res
= sarray_get_safe (object
->class_pointer
->dtable
, (size_t) sel
->sel_id
);
228 /* This is the lookup function. All entries in the table are either a
229 valid method *or* zero. If zero then either the dispatch table
230 needs to be installed or it doesn't exist and forwarding is attempted. */
233 objc_msg_lookup (id receiver
, SEL op
)
238 result
= sarray_get_safe (receiver
->class_pointer
->dtable
,
242 /* Not a valid method */
243 if (receiver
->class_pointer
->dtable
== __objc_uninstalled_dtable
)
245 /* The dispatch table needs to be installed.
246 This happens on the very first method call to the class. */
247 __objc_init_install_dtable (receiver
, op
);
249 /* Get real method for this in newly installed dtable */
250 result
= get_imp (receiver
->class_pointer
, op
);
254 /* The dispatch table has been installed. Check again
255 if the method exists (just in case the dispatch table
256 has been installed by another thread after we did the
257 previous check that the method exists).
259 result
= sarray_get_safe (receiver
->class_pointer
->dtable
,
263 /* If the method still just doesn't exist for the
264 class, attempt to forward the method. */
265 result
= __objc_get_forward_imp (receiver
, op
);
272 return (IMP
)nil_method
;
276 objc_msg_lookup_super (Super_t super
, SEL sel
)
279 return get_imp (super
->class, sel
);
281 return (IMP
)nil_method
;
284 int method_get_sizeof_arguments (Method
*);
287 objc_msg_sendv (id object
, SEL op
, arglist_t arg_frame
)
289 Method
*m
= class_get_instance_method (object
->class_pointer
, op
);
291 *((id
*) method_get_first_argument (m
, arg_frame
, &type
)) = object
;
292 *((SEL
*) method_get_next_argument (arg_frame
, &type
)) = op
;
293 return __builtin_apply ((apply_t
) m
->method_imp
,
295 method_get_sizeof_arguments (m
));
299 __objc_init_dispatch_tables ()
301 __objc_uninstalled_dtable
= sarray_new (200, 0);
304 /* This function is called by objc_msg_lookup when the
305 dispatch table needs to be installed; thus it is called once
306 for each class, namely when the very first message is sent to it. */
308 __objc_init_install_dtable (id receiver
, SEL op
__attribute__ ((__unused__
)))
310 objc_mutex_lock (__objc_runtime_mutex
);
312 /* This may happen, if the programmer has taken the address of a
313 method before the dtable was initialized... too bad for him! */
314 if (receiver
->class_pointer
->dtable
!= __objc_uninstalled_dtable
)
316 objc_mutex_unlock (__objc_runtime_mutex
);
320 if (CLS_ISCLASS (receiver
->class_pointer
))
322 /* receiver is an ordinary object */
323 assert (CLS_ISCLASS (receiver
->class_pointer
));
325 /* install instance methods table */
326 __objc_install_dispatch_table_for_class (receiver
->class_pointer
);
328 /* call +initialize -- this will in turn install the factory
329 dispatch table if not already done :-) */
330 __objc_send_initialize (receiver
->class_pointer
);
334 /* receiver is a class object */
335 assert (CLS_ISCLASS ((Class
)receiver
));
336 assert (CLS_ISMETA (receiver
->class_pointer
));
338 /* Install real dtable for factory methods */
339 __objc_install_dispatch_table_for_class (receiver
->class_pointer
);
341 __objc_send_initialize ((Class
)receiver
);
343 objc_mutex_unlock (__objc_runtime_mutex
);
346 /* Install dummy table for class which causes the first message to
347 that class (or instances hereof) to be initialized properly */
349 __objc_install_premature_dtable (Class
class)
351 assert (__objc_uninstalled_dtable
);
352 class->dtable
= __objc_uninstalled_dtable
;
355 /* Send +initialize to class if not already done */
357 __objc_send_initialize (Class
class)
359 /* This *must* be a class object */
360 assert (CLS_ISCLASS (class));
361 assert (! CLS_ISMETA (class));
363 if (! CLS_ISINITIALIZED (class))
365 CLS_SETINITIALIZED (class);
366 CLS_SETINITIALIZED (class->class_pointer
);
368 /* Create the garbage collector type memory description */
369 __objc_generate_gc_type_description (class);
371 if (class->super_class
)
372 __objc_send_initialize (class->super_class
);
375 SEL op
= sel_register_name ("initialize");
377 MethodList_t method_list
= class->class_pointer
->methods
;
379 while (method_list
) {
383 for (i
= 0; i
< method_list
->method_count
; i
++) {
384 method
= &(method_list
->method_list
[i
]);
385 if (method
->method_name
386 && method
->method_name
->sel_id
== op
->sel_id
) {
387 imp
= method
->method_imp
;
395 method_list
= method_list
->method_next
;
399 (*imp
) ((id
) class, op
);
405 /* Walk on the methods list of class and install the methods in the reverse
406 order of the lists. Since methods added by categories are before the methods
407 of class in the methods list, this allows categories to substitute methods
408 declared in class. However if more than one category replaces the same
409 method nothing is guaranteed about what method will be used.
410 Assumes that __objc_runtime_mutex is locked down. */
412 __objc_install_methods_in_dtable (Class
class, MethodList_t method_list
)
419 if (method_list
->method_next
)
420 __objc_install_methods_in_dtable (class, method_list
->method_next
);
422 for (i
= 0; i
< method_list
->method_count
; i
++)
424 Method_t method
= &(method_list
->method_list
[i
]);
425 sarray_at_put_safe (class->dtable
,
426 (sidx
) method
->method_name
->sel_id
,
431 /* Assumes that __objc_runtime_mutex is locked down. */
433 __objc_install_dispatch_table_for_class (Class
class)
437 /* If the class has not yet had its class links resolved, we must
438 re-compute all class links */
439 if (! CLS_ISRESOLV (class))
440 __objc_resolve_class_links ();
442 super
= class->super_class
;
444 if (super
!= 0 && (super
->dtable
== __objc_uninstalled_dtable
))
445 __objc_install_dispatch_table_for_class (super
);
447 /* Allocate dtable if necessary */
450 objc_mutex_lock (__objc_runtime_mutex
);
451 class->dtable
= sarray_new (__objc_selector_max_index
, 0);
452 objc_mutex_unlock (__objc_runtime_mutex
);
455 class->dtable
= sarray_lazy_copy (super
->dtable
);
457 __objc_install_methods_in_dtable (class, class->methods
);
461 __objc_update_dispatch_table_for_class (Class
class)
466 /* not yet installed -- skip it */
467 if (class->dtable
== __objc_uninstalled_dtable
)
470 objc_mutex_lock (__objc_runtime_mutex
);
473 __objc_install_premature_dtable (class); /* someone might require it... */
474 sarray_free (arr
); /* release memory */
476 /* could have been lazy... */
477 __objc_install_dispatch_table_for_class (class);
479 if (class->subclass_list
) /* Traverse subclasses */
480 for (next
= class->subclass_list
; next
; next
= next
->sibling_class
)
481 __objc_update_dispatch_table_for_class (next
);
483 objc_mutex_unlock (__objc_runtime_mutex
);
487 /* This function adds a method list to a class. This function is
488 typically called by another function specific to the run-time. As
489 such this function does not worry about thread safe issues.
491 This one is only called for categories. Class objects have their
492 methods installed right away, and their selectors are made into
493 SEL's by the function __objc_register_selectors_from_class. */
495 class_add_method_list (Class
class, MethodList_t list
)
497 /* Passing of a linked list is not allowed. Do multiple calls. */
498 assert (! list
->method_next
);
500 __objc_register_selectors_from_list(list
);
502 /* Add the methods to the class's method list. */
503 list
->method_next
= class->methods
;
504 class->methods
= list
;
506 /* Update the dispatch table of class */
507 __objc_update_dispatch_table_for_class (class);
511 class_get_instance_method (Class
class, SEL op
)
513 return search_for_method_in_hierarchy (class, op
);
517 class_get_class_method (MetaClass
class, SEL op
)
519 return search_for_method_in_hierarchy (class, op
);
523 /* Search for a method starting from the current class up its hierarchy.
524 Return a pointer to the method's method structure if found. NULL
528 search_for_method_in_hierarchy (Class cls
, SEL sel
)
530 Method_t method
= NULL
;
533 if (! sel_is_mapped (sel
))
536 /* Scan the method list of the class. If the method isn't found in the
537 list then step to its super class. */
538 for (class = cls
; ((! method
) && class); class = class->super_class
)
539 method
= search_for_method_in_list (class->methods
, sel
);
546 /* Given a linked list of method and a method's name. Search for the named
547 method's method structure. Return a pointer to the method's method
548 structure if found. NULL otherwise. */
550 search_for_method_in_list (MethodList_t list
, SEL op
)
552 MethodList_t method_list
= list
;
554 if (! sel_is_mapped (op
))
557 /* If not found then we'll search the list. */
562 /* Search the method list. */
563 for (i
= 0; i
< method_list
->method_count
; ++i
)
565 Method_t method
= &method_list
->method_list
[i
];
567 if (method
->method_name
)
568 if (method
->method_name
->sel_id
== op
->sel_id
)
572 /* The method wasn't found. Follow the link to the next list of
574 method_list
= method_list
->method_next
;
580 static retval_t
__objc_forward (id object
, SEL sel
, arglist_t args
);
582 /* Forwarding pointers/integers through the normal registers */
584 __objc_word_forward (id rcv
, SEL op
, ...)
588 args
= __builtin_apply_args ();
589 res
= __objc_forward (rcv
, op
, args
);
591 __builtin_return (res
);
596 /* Specific routine for forwarding floats/double because of
597 architectural differences on some processors. i386s for
598 example which uses a floating point stack versus general
599 registers for floating point numbers. This forward routine
600 makes sure that GCC restores the proper return values */
602 __objc_double_forward (id rcv
, SEL op
, ...)
606 args
= __builtin_apply_args ();
607 res
= __objc_forward (rcv
, op
, args
);
608 __builtin_return (res
);
611 #if INVISIBLE_STRUCT_RETURN
616 __objc_block_forward (id rcv
, SEL op
, ...)
620 args
= __builtin_apply_args ();
621 res
= __objc_forward (rcv
, op
, args
);
623 __builtin_return (res
);
625 #if INVISIBLE_STRUCT_RETURN
626 return (__big
) {{0, 0, 0, 0, 0, 0, 0, 0}};
633 /* This function is installed in the dispatch table for all methods which are
634 not implemented. Thus, it is called when a selector is not recognized. */
636 __objc_forward (id object
, SEL sel
, arglist_t args
)
639 static SEL frwd_sel
= 0; /* !T:SAFE2 */
642 /* first try if the object understands forward:: */
644 frwd_sel
= sel_get_any_uid ("forward::");
646 if (__objc_responds_to (object
, frwd_sel
))
648 imp
= get_imp (object
->class_pointer
, frwd_sel
);
649 return (*imp
) (object
, frwd_sel
, sel
, args
);
652 /* If the object recognizes the doesNotRecognize: method then we're going
654 err_sel
= sel_get_any_uid ("doesNotRecognize:");
655 if (__objc_responds_to (object
, err_sel
))
657 imp
= get_imp (object
->class_pointer
, err_sel
);
658 return (*imp
) (object
, err_sel
, sel
);
661 /* The object doesn't recognize the method. Check for responding to
662 error:. If it does then sent it. */
664 char msg
[256 + strlen ((const char *) sel_get_name (sel
))
665 + strlen ((const char *) object
->class_pointer
->name
)];
667 sprintf (msg
, "(%s) %s does not recognize %s",
668 (CLS_ISMETA (object
->class_pointer
)
671 object
->class_pointer
->name
, sel_get_name (sel
));
673 /* TODO: support for error: is surely deprecated ? */
674 err_sel
= sel_get_any_uid ("error:");
675 if (__objc_responds_to (object
, err_sel
))
677 imp
= get_imp (object
->class_pointer
, err_sel
);
678 return (*imp
) (object
, sel_get_any_uid ("error:"), msg
);
681 /* The object doesn't respond to doesNotRecognize: or error:; Therefore,
682 a default action is taken. */
683 _objc_abort ("%s\n", msg
);
690 __objc_print_dtable_stats ()
694 objc_mutex_lock (__objc_runtime_mutex
);
697 printf ("memory usage: (%s)\n", "2-level sparse arrays");
699 printf ("memory usage: (%s)\n", "3-level sparse arrays");
702 printf ("arrays: %d = %ld bytes\n", narrays
,
703 (long) ((size_t) narrays
* sizeof (struct sarray
)));
704 total
+= narrays
* sizeof (struct sarray
);
705 printf ("buckets: %d = %ld bytes\n", nbuckets
,
706 (long) ((size_t) nbuckets
* sizeof (struct sbucket
)));
707 total
+= nbuckets
* sizeof (struct sbucket
);
709 printf ("idxtables: %d = %ld bytes\n",
710 idxsize
, (long) ((size_t) idxsize
* sizeof (void *)));
711 total
+= idxsize
* sizeof (void *);
712 printf ("-----------------------------------\n");
713 printf ("total: %d bytes\n", total
);
714 printf ("===================================\n");
716 objc_mutex_unlock (__objc_runtime_mutex
);
719 /* Returns the uninstalled dispatch table indicator.
720 If a class' dispatch table points to __objc_uninstalled_dtable
721 then that means it needs its dispatch table to be installed. */
724 objc_get_uninstalled_dtable ()
726 return __objc_uninstalled_dtable
;