diff options
Diffstat (limited to 'libobjc/sendmsg.c')
| -rw-r--r-- | libobjc/sendmsg.c | 701 |
1 files changed, 701 insertions, 0 deletions
diff --git a/libobjc/sendmsg.c b/libobjc/sendmsg.c new file mode 100644 index 0000000..9453ef3 --- /dev/null +++ b/libobjc/sendmsg.c @@ -0,0 +1,701 @@ +/* GNU Objective C Runtime message lookup + Copyright (C) 1993, 1995, 1996, 1997, 1998, + 2001, 2002, 2004 Free Software Foundation, Inc. + Contributed by Kresten Krab Thorup + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify it under the +terms of the GNU General Public License as published by the Free Software +Foundation; either version 2, or (at your option) any later version. + +GCC is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS +FOR A PARTICULAR PURPOSE. See the GNU General Public License for more +details. + +You should have received a copy of the GNU General Public License along with +GCC; see the file COPYING. If not, write to the Free Software +Foundation, 51 Franklin Street, Fifth Floor, +Boston, MA 02110-1301, USA. */ + +/* As a special exception, if you link this library with files compiled with + GCC to produce an executable, this does not cause the resulting executable + to be covered by the GNU General Public License. This exception does not + however invalidate any other reasons why the executable file might be + covered by the GNU General Public License. */ + +/* FIXME: This file has no business including tm.h. */ +/* FIXME: This should be using libffi instead of __builtin_apply + and friends. */ + +#include "tconfig.h" +#include "coretypes.h" +#include "tm.h" +#include "objc/runtime.h" +#include "objc/sarray.h" +#include "objc/encoding.h" +#include "runtime-info.h" + +/* 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 +#define rtx int + +#if ! defined (STRUCT_VALUE) || STRUCT_VALUE == 0 +#define INVISIBLE_STRUCT_RETURN 1 +#else +#define INVISIBLE_STRUCT_RETURN 0 +#endif + +/* The uninstalled dispatch table */ +struct sarray *__objc_uninstalled_dtable = 0; /* !T:MUTEX */ + +/* Hook for method forwarding. If it is set, is invoked to return a + function that performs the real forwarding. Otherwise the libgcc + based functions (__builtin_apply and friends) are used. */ +IMP (*__objc_msg_forward) (SEL) = NULL; + +/* 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); + +/* 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. + */ +static double __objc_double_forward (id, SEL, ...); +static id __objc_word_forward (id, SEL, ...); +typedef struct { id many[8]; } __big; +#if INVISIBLE_STRUCT_RETURN +static __big +#else +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); +id nil_method (id, SEL); + +/* Given a selector, return the proper forwarding implementation. */ +inline +IMP +__objc_get_forward_imp (SEL sel) +{ + /* If a custom forwarding hook was registered, try getting a forwarding + * function from it. */ + if (__objc_msg_forward) + { + IMP result; + if ((result = __objc_msg_forward (sel)) != NULL) + return result; + } + + /* 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 +#endif + ) + return (IMP)__objc_block_forward; + else if (t && (*t == 'f' || *t == 'd')) + return (IMP)__objc_double_forward; + else + return (IMP)__objc_word_forward; + } +} + +/* Given a class and selector, return the selector's implementation. */ +inline +IMP +get_imp (Class class, SEL sel) +{ + /* In a vanilla implementation we would first check if the dispatch + table is installed. Here instead, to get more speed in the + standard case (that the dispatch table is installed) we first try + to get the imp using brute force. Only if that fails, we do what + we should have been doing from the very beginning, that is, check + if the dispatch table needs to be installed, install it if it's + not installed, and retrieve the imp from the table if it's + installed. */ + 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 (sel); + } + } + } + return res; +} + +/* 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. */ +inline +BOOL +__objc_responds_to (id object, SEL sel) +{ + void *res; + + /* Install dispatch table if need be */ + if (object->class_pointer->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_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); +} + +/* 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 +IMP +objc_msg_lookup (id receiver, SEL op) +{ + IMP result; + if (receiver) + { + 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 (op); + } + } + } + return result; + } + else + return (IMP)nil_method; +} + +IMP +objc_msg_lookup_super (Super_t super, SEL sel) +{ + if (super->self) + return get_imp (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); +} + +/* Install dummy table for class which causes the first message to + that class (or instances hereof) to be initialized properly */ +void +__objc_install_premature_dtable (Class class) +{ + assert (__objc_uninstalled_dtable); + class->dtable = __objc_uninstalled_dtable; +} + +/* Send +initialize to class if not already done */ +static void +__objc_send_initialize (Class class) +{ + /* This *must* be a class object */ + assert (CLS_ISCLASS (class)); + assert (! CLS_ISMETA (class)); + + if (! CLS_ISINITIALIZED (class)) + { + CLS_SETINITIALIZED (class); + CLS_SETINITIALIZED (class->class_pointer); + + /* 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); + + } + } +} + +/* 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) +{ + int i; + + if (! method_list) + return; + + if (method_list->method_next) + __objc_install_methods_in_dtable (class, 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, + (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; + + objc_mutex_lock (__objc_runtime_mutex); + + arr = class->dtable; + __objc_install_premature_dtable (class); /* someone might require it... */ + sarray_free (arr); /* release memory */ + + /* could have been lazy... */ + __objc_install_dispatch_table_for_class (class); + + 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. */ +void +class_add_method_list (Class class, MethodList_t list) +{ + /* Passing of a linked list is not allowed. Do multiple calls. */ + assert (! list->method_next); + + __objc_register_selectors_from_list(list); + + /* Add the methods to the class's method list. */ + list->method_next = class->methods; + class->methods = list; + + /* Update the dispatch table of class */ + __objc_update_dispatch_table_for_class (class); +} + +Method_t +class_get_instance_method (Class class, SEL op) +{ + return search_for_method_in_hierarchy (class, op); +} + +Method_t +class_get_class_method (MetaClass class, SEL op) +{ + return search_for_method_in_hierarchy (class, op); +} + + +/* 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 Method_t +search_for_method_in_hierarchy (Class cls, SEL sel) +{ + Method_t 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. */ + for (class = cls; ((! method) && class); class = class->super_class) + method = search_for_method_in_list (class->methods, sel); + + return method; +} + + + +/* 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) +{ + MethodList_t method_list = list; + + if (! sel_is_mapped (op)) + return NULL; + + /* If not found then we'll search the list. */ + while (method_list) + { + int i; + + /* Search the method list. */ + for (i = 0; i < method_list->method_count; ++i) + { + Method_t method = &method_list->method_list[i]; + + if (method->method_name) + if (method->method_name->sel_id == op->sel_id) + return method; + } + + /* The method wasn't found. Follow the link to the next list of + methods. */ + method_list = method_list->method_next; + } + + return NULL; +} + +static retval_t __objc_forward (id object, SEL sel, arglist_t args); + +/* Forwarding pointers/integers through the normal registers */ +static id +__objc_word_forward (id rcv, SEL op, ...) +{ + void *args, *res; + + args = __builtin_apply_args (); + res = __objc_forward (rcv, op, args); + if (res) + __builtin_return (res); + else + return res; +} + +/* 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 */ +static double +__objc_double_forward (id rcv, SEL op, ...) +{ + void *args, *res; + + args = __builtin_apply_args (); + res = __objc_forward (rcv, op, args); + __builtin_return (res); +} + +#if INVISIBLE_STRUCT_RETURN +static __big +#else +static id +#endif +__objc_block_forward (id rcv, SEL op, ...) +{ + void *args, *res; + + args = __builtin_apply_args (); + res = __objc_forward (rcv, op, args); + if (res) + __builtin_return (res); + else +#if INVISIBLE_STRUCT_RETURN + return (__big) {{0, 0, 0, 0, 0, 0, 0, 0}}; +#else + return nil; +#endif +} + + +/* 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. */ +static retval_t +__objc_forward (id object, SEL sel, arglist_t args) +{ + IMP imp; + static SEL frwd_sel = 0; /* !T:SAFE2 */ + SEL err_sel; + + /* 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); + return (*imp) (object, frwd_sel, sel, args); + } + + /* 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); + return (*imp) (object, err_sel, sel); + } + + /* The object doesn't recognize the method. Check for responding to + error:. If it does then sent it. */ + { + char msg[256 + strlen ((const char *) sel_get_name (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); + } + + /* The object doesn't respond to doesNotRecognize: or error:; Therefore, + a default action is taken. */ + objc_error (object, OBJC_ERR_UNIMPLEMENTED, "%s\n", msg); + + return 0; + } +} + +void +__objc_print_dtable_stats () +{ + int total = 0; + + objc_mutex_lock (__objc_runtime_mutex); + +#ifdef OBJC_SPARSE2 + printf ("memory usage: (%s)\n", "2-level sparse arrays"); +#else + printf ("memory usage: (%s)\n", "3-level sparse arrays"); +#endif + + printf ("arrays: %d = %ld bytes\n", narrays, + (long) narrays * sizeof (struct sarray)); + total += narrays * sizeof (struct sarray); + printf ("buckets: %d = %ld bytes\n", nbuckets, + (long) nbuckets * sizeof (struct sbucket)); + total += nbuckets * sizeof (struct sbucket); + + printf ("idxtables: %d = %ld bytes\n", + idxsize, (long) idxsize * sizeof (void *)); + total += idxsize * sizeof (void *); + printf ("-----------------------------------\n"); + printf ("total: %d bytes\n", total); + printf ("===================================\n"); + + 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 () +{ + return __objc_uninstalled_dtable; +} |
