/* GNU Objective C Runtime message lookup Copyright (C) 1993, 1995, 1996, 1997 Free Software Foundation, Inc. Contributed by Kresten Krab Thorup This file is part of GNU CC. GNU CC 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. GNU CC 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 GNU CC; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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. */ #include "../tconfig.h" #include "runtime.h" #include "sarray.h" #include "encoding.h" #include "runtime-info.h" /* this is how we hack STRUCT_VALUE to be 1 or 0 */ #define gen_rtx(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 */ /* 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) { 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) { 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); __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 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); __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 so the method just doesn't exist for the class. Attempt to forward the method. */ result = __objc_get_forward_imp(op); } } return result; } else return nil_method; } IMP objc_msg_lookup_super (Super_t super, SEL sel) { if (super->self) return get_imp (super->class, sel); else return 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) { /* 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) return; objc_mutex_lock(__objc_runtime_mutex); 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); if (strcmp (sel_get_name (op), "initialize")) __objc_send_initialize((Class)receiver); else CLS_SETINITIALIZED((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); if(class->super_class) __objc_send_initialize(class->super_class); { SEL op = sel_register_name ("initialize"); Class tmpclass = class; IMP imp = 0; while (!imp && tmpclass) { MethodList_t method_list = tmpclass->class_pointer->methods; while(!imp && method_list) { int i; Method_t method; for (i=0;imethod_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; } } method_list = method_list->method_next; } tmpclass = tmpclass->super_class; } 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 it's 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) { int i; /* Passing of a linked list is not allowed. Do multiple calls. */ assert (!list->method_next); /* Check for duplicates. */ for (i = 0; i < list->method_count; ++i) { Method_t method = &list->method_list[i]; if (method->method_name) /* Sometimes these are NULL */ { /* This is where selector names are transmogrified to SEL's */ method->method_name = sel_register_typed_name ((const char*)method->method_name, method->method_types); } } /* 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}; #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. */ { size_t strlen (const char*); 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); printf("memory usage: (%s)\n", #ifdef OBJC_SPARSE2 "2-level sparse arrays" #else "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; }