objc-act.c

gcc库的原代码,对编程有很大帮助.

static tree
init_def_list (type)
     tree type;
{
  tree expr, initlist = NULL_TREE;
  struct imp_entry *impent;

  if (imp_count)
    for (impent = imp_list; impent; impent = impent->next)
      {
	if (TREE_CODE (impent->imp_context) == CLASS_IMPLEMENTATION_TYPE)
	  {
	    expr = build_unary_op (ADDR_EXPR, impent->class_decl, 0);
	    initlist = tree_cons (NULL_TREE, expr, initlist);
	  }
      }

  if (cat_count)
    for (impent = imp_list; impent; impent = impent->next)
      {
	if (TREE_CODE (impent->imp_context) == CATEGORY_IMPLEMENTATION_TYPE)
	  {
	    expr = build_unary_op (ADDR_EXPR, impent->class_decl, 0);
	    initlist = tree_cons (NULL_TREE, expr, initlist);
	  }
      }

  return build_constructor (type, nreverse (initlist));
}

/* Construct the initial value for all of _objc_symtab.  */

static tree
init_objc_symtab (type)
     tree type;
{
  tree initlist;

  /* sel_ref_cnt = { ..., 5, ... } */

  initlist = build_tree_list (NULL_TREE, build_int_2 (0, 0));

  /* refs = { ..., _OBJC_SELECTOR_TABLE, ... } */

  if (flag_next_runtime || ! sel_ref_chain)
    initlist = tree_cons (NULL_TREE, build_int_2 (0, 0), initlist);
  else
    initlist = tree_cons (NULL_TREE,
			  build_unary_op (ADDR_EXPR,
					  UOBJC_SELECTOR_TABLE_decl, 1),
			  initlist);

  /* cls_def_cnt = { ..., 5, ... } */

  initlist = tree_cons (NULL_TREE, build_int_2 (imp_count, 0), initlist);

  /* cat_def_cnt = { ..., 5, ... } */

  initlist = tree_cons (NULL_TREE, build_int_2 (cat_count, 0), initlist);

  /* cls_def = { ..., { &Foo, &Bar, ...}, ... } */

  if (imp_count || cat_count)
    {
      tree field = TYPE_FIELDS (type);
      field = TREE_CHAIN (TREE_CHAIN (TREE_CHAIN (TREE_CHAIN (field))));

      initlist = tree_cons (NULL_TREE, init_def_list (TREE_TYPE (field)),
			    initlist);
    }

  return build_constructor (type, nreverse (initlist));
}

/* Push forward-declarations of all the categories
   so that init_def_list can use them in a CONSTRUCTOR.  */

static void
forward_declare_categories ()
{
  struct imp_entry *impent;
  tree sav = implementation_context;

  for (impent = imp_list; impent; impent = impent->next)
    {
      if (TREE_CODE (impent->imp_context) == CATEGORY_IMPLEMENTATION_TYPE)
	{
	  /* Set an invisible arg to synth_id_with_class_suffix.  */
	  implementation_context = impent->imp_context;
	  impent->class_decl
	    = create_builtin_decl (VAR_DECL, objc_category_template,
				   IDENTIFIER_POINTER (synth_id_with_class_suffix ("_OBJC_CATEGORY", implementation_context)));
	}
    }
  implementation_context = sav;
}

/* Create the declaration of _OBJC_SYMBOLS, with type `strict _objc_symtab'
   and initialized appropriately.  */

static void
generate_objc_symtab_decl ()
{
  tree sc_spec;

  if (!objc_category_template)
    build_category_template ();

  /* forward declare categories */
  if (cat_count)
    forward_declare_categories ();

  if (!objc_symtab_template)
    build_objc_symtab_template ();

  sc_spec = build_tree_list (NULL_TREE, ridpointers[(int) RID_STATIC]);

  UOBJC_SYMBOLS_decl = start_decl (get_identifier ("_OBJC_SYMBOLS"),
				   tree_cons (NULL_TREE,
					      objc_symtab_template, sc_spec),
				   1,
				   NULL_TREE, NULL_TREE);

  TREE_USED (UOBJC_SYMBOLS_decl) = 1;
  DECL_IGNORED_P (UOBJC_SYMBOLS_decl) = 1;
  DECL_ARTIFICIAL (UOBJC_SYMBOLS_decl) = 1;
  finish_decl (UOBJC_SYMBOLS_decl,
	       init_objc_symtab (TREE_TYPE (UOBJC_SYMBOLS_decl)),
	       NULL_TREE);
}

static tree
init_module_descriptor (type)
     tree type;
{
  tree initlist, expr;

  /* version = { 1, ... } */

  expr = build_int_2 (OBJC_VERSION, 0);
  initlist = build_tree_list (NULL_TREE, expr);

  /* size = { ..., sizeof (struct objc_module), ... } */

  expr = size_in_bytes (objc_module_template);
  initlist = tree_cons (NULL_TREE, expr, initlist);

  /* name = { ..., "foo.m", ... } */

  expr = add_objc_string (get_identifier (input_filename), class_names);
  initlist = tree_cons (NULL_TREE, expr, initlist);


  if (!flag_next_runtime)
    {
      /* statics = { ..., _OBJC_STATIC_INSTANCES, ... }  */
      if (static_instances_decl)
	expr = build_unary_op (ADDR_EXPR, static_instances_decl, 0);
      else
	expr = build_int_2 (0, 0);
      initlist = tree_cons (NULL_TREE, expr, initlist);
    }

  /* symtab = { ..., _OBJC_SYMBOLS, ... } */

  if (UOBJC_SYMBOLS_decl)
    expr = build_unary_op (ADDR_EXPR, UOBJC_SYMBOLS_decl, 0);
  else
    expr = build_int_2 (0, 0);
  initlist = tree_cons (NULL_TREE, expr, initlist);

  return build_constructor (type, nreverse (initlist));
}

/* Write out the data structures to describe Objective C classes defined.
   If appropriate, compile and output a setup function to initialize them.
   Return a string which is the name of a function to call to initialize
   the Objective C data structures for this file (and perhaps for other files
   also).

   struct objc_module { ... } _OBJC_MODULE = { ... };   */

static char *
build_module_descriptor ()
{
  tree decl_specs, field_decl, field_decl_chain;

  objc_module_template
    = start_struct (RECORD_TYPE, get_identifier (UTAG_MODULE));

  /* Long version; */

  decl_specs = build_tree_list (NULL_TREE, ridpointers[(int) RID_LONG]);
  field_decl = get_identifier ("version");
  field_decl
    = grokfield (input_filename, lineno, field_decl, decl_specs, NULL_TREE);
  field_decl_chain = field_decl;

  /* long  size; */

  decl_specs = build_tree_list (NULL_TREE, ridpointers[(int) RID_LONG]);
  field_decl = get_identifier ("size");
  field_decl
    = grokfield (input_filename, lineno, field_decl, decl_specs, NULL_TREE);
  chainon (field_decl_chain, field_decl);

  /* char  *name; */

  decl_specs = build_tree_list (NULL_TREE, ridpointers[(int) RID_CHAR]);
  field_decl = build1 (INDIRECT_REF, NULL_TREE, get_identifier ("name"));
  field_decl
    = grokfield (input_filename, lineno, field_decl, decl_specs, NULL_TREE);
  chainon (field_decl_chain, field_decl);


  if (!flag_next_runtime)
    {
      /* void *statics */

      decl_specs = get_identifier (UTAG_STATICS);
      decl_specs
	= build_tree_list (NULL_TREE, xref_tag (RECORD_TYPE, decl_specs));
      field_decl
	= build1 (INDIRECT_REF, NULL_TREE, get_identifier ("statics"));
      field_decl = grokfield (input_filename, lineno, field_decl,
			      decl_specs, NULL_TREE);
      chainon (field_decl_chain, field_decl);
    }


  /* struct objc_symtab *symtab; */

  decl_specs = get_identifier (UTAG_SYMTAB);
  decl_specs = build_tree_list (NULL_TREE, xref_tag (RECORD_TYPE, decl_specs));
  field_decl = build1 (INDIRECT_REF, NULL_TREE, get_identifier ("symtab"));
  field_decl
    = grokfield (input_filename, lineno, field_decl, decl_specs, NULL_TREE);
  chainon (field_decl_chain, field_decl);

  finish_struct (objc_module_template, field_decl_chain, NULL_TREE);

  /* Create an instance of "objc_module". */

  decl_specs = tree_cons (NULL_TREE, objc_module_template,
			  build_tree_list (NULL_TREE,
					   ridpointers[(int) RID_STATIC]));

  UOBJC_MODULES_decl = start_decl (get_identifier ("_OBJC_MODULES"),
				   decl_specs, 1, NULL_TREE, NULL_TREE);

  DECL_ARTIFICIAL (UOBJC_MODULES_decl) = 1;
  DECL_IGNORED_P (UOBJC_MODULES_decl) = 1;
  finish_decl (UOBJC_MODULES_decl,
	       init_module_descriptor (TREE_TYPE (UOBJC_MODULES_decl)),
	       NULL_TREE);

  /* Mark the decl to avoid "defined but not used" warning. */
  DECL_IN_SYSTEM_HEADER (UOBJC_MODULES_decl) = 1;

  /* Generate a constructor call for the module descriptor.
     This code was generated by reading the grammar rules
     of c-parse.in;  Therefore, it may not be the most efficient
     way of generating the requisite code. */

  if (flag_next_runtime)
    return 0;

  {
    tree parms, function_decl, decelerator, void_list_node;
    tree function_type;
    extern tree get_file_function_name ();
    tree init_function_name = get_file_function_name ('I');

    /* Declare void __objc_execClass (void*); */

    void_list_node = build_tree_list (NULL_TREE, void_type_node);
    function_type
      = build_function_type (void_type_node,
			     tree_cons (NULL_TREE, ptr_type_node,
					void_list_node));
    function_decl = build_decl (FUNCTION_DECL,
				get_identifier (TAG_EXECCLASS),
				function_type);
    DECL_EXTERNAL (function_decl) = 1;
    DECL_ARTIFICIAL (function_decl) = 1;
    TREE_PUBLIC (function_decl) = 1;

    pushdecl (function_decl);
    rest_of_decl_compilation (function_decl, 0, 0, 0);

    parms
      = build_tree_list (NULL_TREE,
			 build_unary_op (ADDR_EXPR, UOBJC_MODULES_decl, 0));
    decelerator = build_function_call (function_decl, parms);

    /* void _GLOBAL_$I$<gnyf> () {objc_execClass (&L_OBJC_MODULES);}  */

    start_function (void_list_node,
		    build_parse_node (CALL_EXPR, init_function_name,
				      /* This has the format of the output
					 of get_parm_info.  */
				      tree_cons (NULL_TREE, NULL_TREE,
						 void_list_node),
				      NULL_TREE),
		    NULL_TREE, NULL_TREE, 0);
#if 0 /* This should be turned back on later
	 for the systems where collect is not needed.  */
    /* Make these functions nonglobal
       so each file can use the same name.  */
    TREE_PUBLIC (current_function_decl) = 0;
#endif
    TREE_USED (current_function_decl) = 1;
    store_parm_decls ();

    assemble_external (function_decl);
    c_expand_expr_stmt (decelerator);

    TREE_PUBLIC (current_function_decl) = 1;

    function_decl = current_function_decl;
    finish_function (0);

    /* Return the name of the constructor function.  */
    return XSTR (XEXP (DECL_RTL (function_decl), 0), 0);
  }
}

/* extern const char _OBJC_STRINGS[]; */

static void
generate_forward_declaration_to_string_table ()
{
  tree sc_spec, decl_specs, expr_decl;

  sc_spec = tree_cons (NULL_TREE, ridpointers[(int) RID_EXTERN], NULL_TREE);
  decl_specs = tree_cons (NULL_TREE, ridpointers[(int) RID_CHAR], sc_spec);

  expr_decl
    = build_nt (ARRAY_REF, get_identifier ("_OBJC_STRINGS"), NULL_TREE);

  UOBJC_STRINGS_decl = define_decl (expr_decl, decl_specs);
}

/* Return the DECL of the string IDENT in the SECTION.  */

static tree
get_objc_string_decl (ident, section)
     tree ident;
     enum string_section section;
{
  tree chain, decl;

  if (section == class_names)
    chain = class_names_chain;
  else if (section == meth_var_names)
    chain = meth_var_names_chain;
  else if (section == meth_var_types)
    chain = meth_var_types_chain;

  for (; chain != 0; chain = TREE_VALUE (chain))
    if (TREE_VALUE (chain) == ident)
      return (TREE_PURPOSE (chain));

  abort ();
  return NULL_TREE;
}

/* Output references to all statically allocated objects.  Return the DECL
   for the array built.  */

static tree
generate_static_references ()
{
  tree decls = NULL_TREE, ident, decl_spec, expr_decl, expr = NULL_TREE;
  tree class_name, class, decl, instance, idecl, initlist;
  tree cl_chain, in_chain, type;
  int num_inst, num_class;
  char buf[256];

  if (flag_next_runtime)
    abort ();

  for (cl_chain = objc_static_instances, num_class = 0;
       cl_chain; cl_chain = TREE_CHAIN (cl_chain), num_class++)
    {
      for (num_inst = 0, in_chain = TREE_PURPOSE (cl_chain);
	   in_chain; num_inst++, in_chain = TREE_CHAIN (in_chain));

      sprintf (buf, "_OBJC_STATIC_INSTANCES_%d", num_class);
      ident = get_identifier (buf);

      expr_decl = build_nt (ARRAY_REF, ident, NULL_TREE);
      decl_spec = tree_cons (NULL_TREE, build_pointer_type (void_type_node),
			     build_tree_list (NULL_TREE,
					      ridpointers[(int) RID_STATIC]));
      decl = start_decl (expr_decl, decl_spec, 1, NULL_TREE, NULL_TREE);
      DECL_CONTEXT (decl) = 0;
      DECL_ARTIFICIAL (decl) = 1;

      /* Output {class_name, ...}.  */
      class = TREE_VALUE (cl_chain);
      class_name = get_objc_string_decl (TYPE_NAME (class), class_names);
      initlist = build_tree_list (NULL_TREE,
				  build_unary_op (ADDR_EXPR, class_name, 1));

      /* Output {..., instance, ...}.  */
      for (in_chain = TREE_PURPOSE (cl_chain);
	   in_chain; in_chain = TREE_CHAIN (in_chain))
	{
	  expr = build_unary_op (ADDR_EXPR, TREE_VALUE (in_chain), 1);
	  initlist = tree_cons (NULL_TREE, expr, initlist);
	}

      /* Output {..., NULL}.  */
      initlist = tree_cons (NULL_TREE, build_int_2 (0, 0), initlist);

      expr = build_constructor (TREE_TYPE (decl), nreverse (initlist));
      finish_decl (decl, expr, NULL_TREE);
      TREE_USED (decl) = 1;

      type = build_array_type (build_pointer_type (void_type_node), 0);
      decl = build_decl (VAR_DECL, ident, type);
      make_decl_rtl (decl, 0, 1);
      TREE_USED (decl) = 1;
      decls
	= tree_cons (NULL_TREE, build_unary_op (ADDR_EXPR, decl, 1), decls);
    }

  decls = tree_cons (NULL_TREE, build_int_2 (0, 0), decls);
  ident = get_identifier ("_OBJC_STATIC_INSTANCES");
  expr_decl = build_nt (ARRAY_REF, ident, NULL_TREE);
  decl_spec = tree_cons (NULL_TREE, build_pointer_type (void_type_node),
			 build_tree_list (NULL_TREE,
					  ridpointers[(int) RID_STATIC]));
  static_instances_decl
    = start_decl (expr_decl, decl_spec, 1, NULL_TREE, NULL_TREE);
  DECL_CONTEXT (static_instances_decl) = 0;
  DECL_ARTIFICIAL (static_instances_decl) = 1;
  end_temporary_allocation ();
  expr = build_constructor (TREE_TYPE (static_instances_decl),
			    nreverse (decls));
  finish_decl (static_instances_decl, expr, NULL_TREE);
}

/* Output all strings. */

static void
generate_strings ()
{
  tree sc_spec, decl_specs, expr_decl;
  tree chain, string_expr;
  tree string, decl;

  for (chain = class_names_chain; chain; chain = TREE_CHAIN (chain))
    {
      string = TREE_VALUE (chain);
      decl = TREE_PURPOSE (chain);
      sc_spec
	= tree_cons (NULL_TREE, ridpointers[(int) RID_STATIC], NULL_TREE);