/* GNU Objective C Runtime message lookup    Copyright (C) 1993, 1995, 1996, 1997 Free Software Foundation, Inc.   Contributed by Kresten Krab ThorupThis file is part of GNU CC.GNU CC is free software; you can redistribute it and/or modify it under theterms of the GNU General Public License as published by the Free SoftwareFoundation; either version 2, or (at your option) any later version.GNU CC is distributed in the hope that it will be useful, but WITHOUT ANYWARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESSFOR A PARTICULAR PURPOSE.  See the GNU General Public License for moredetails.You should have received a copy of the GNU General Public License along withGNU CC; see the file COPYING.  If not, write to the Free SoftwareFoundation, 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 #elsestatic 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__IMPget_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 theobject implements the selector otherwise NO.  Does not check if themethod 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__IMPobjc_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;}IMPobjc_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_tobjc_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;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;	      }	    }	    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;