class.c

gcc库的原代码,对编程有很大帮助.

	  if (might_have_abstract_virtuals)
	    break;
	}
      if (might_have_abstract_virtuals)
	{
	  /* We use error_mark_node from override_one_vtable to signal
	     an artificial abstract. */
	  if (CLASSTYPE_ABSTRACT_VIRTUALS (t) == error_mark_node)
	    CLASSTYPE_ABSTRACT_VIRTUALS (t) = NULL_TREE;
	  CLASSTYPE_ABSTRACT_VIRTUALS (t) = get_abstract_virtuals (t);
	}
    }

  if (n_baseclasses)
    {
      /* Notice whether this class has type conversion functions defined.  */
      tree binfo = TYPE_BINFO (t);
      tree binfos = BINFO_BASETYPES (binfo);
      tree basetype;

      for (i = n_baseclasses-1; i >= 0; i--)
	{
	  basetype = BINFO_TYPE (TREE_VEC_ELT (binfos, i));

	  if (TYPE_HAS_CONVERSION (basetype))
	    {
	      TYPE_HAS_CONVERSION (t) = 1;
	      TYPE_HAS_INT_CONVERSION (t) |= TYPE_HAS_INT_CONVERSION (basetype);
	      TYPE_HAS_REAL_CONVERSION (t) |= TYPE_HAS_REAL_CONVERSION (basetype);
	    }
	  if (CLASSTYPE_MAX_DEPTH (basetype) >= CLASSTYPE_MAX_DEPTH (t))
	    CLASSTYPE_MAX_DEPTH (t) = CLASSTYPE_MAX_DEPTH (basetype) + 1;
	}
    }

  /* If this type has a copy constructor, force its mode to be BLKmode, and
     force its TREE_ADDRESSABLE bit to be nonzero.  This will cause it to
     be passed by invisible reference and prevent it from being returned in
     a register.  */
  if (! TYPE_HAS_TRIVIAL_INIT_REF (t))
    {
      tree variants;
      if (TREE_CODE (TYPE_NAME (t)) == TYPE_DECL)
	DECL_MODE (TYPE_NAME (t)) = BLKmode;
      for (variants = t; variants; variants = TYPE_NEXT_VARIANT (variants))
	{
	  TYPE_MODE (variants) = BLKmode;
	  TREE_ADDRESSABLE (variants) = 1;
	}
    }
}

/* Add FN to the method_vec growing on the class_obstack.  Used by
   finish_struct_methods.  */
static void
grow_method (fn, method_vec_ptr)
     tree fn;
     tree *method_vec_ptr;
{
  tree method_vec = (tree)obstack_base (&class_obstack);
  tree *testp = &TREE_VEC_ELT (method_vec, 0);
  if (*testp == NULL_TREE)
    testp++;
  while (((HOST_WIDE_INT) testp
	  < (HOST_WIDE_INT) obstack_next_free (&class_obstack))
	 && DECL_NAME (*testp) != DECL_NAME (fn))
    testp++;
  if ((HOST_WIDE_INT) testp
      < (HOST_WIDE_INT) obstack_next_free (&class_obstack))
    {
      tree x, prev_x;

      for (x = *testp; x; x = DECL_CHAIN (x))
	{
	  if (DECL_NAME (fn) == ansi_opname[(int) DELETE_EXPR]
	      || DECL_NAME (fn) == ansi_opname[(int) VEC_DELETE_EXPR])
	    {
	      /* ANSI C++ June 5 1992 WP 12.5.5.1 */
	      cp_error_at ("`%D' overloaded", fn);
	      cp_error_at ("previous declaration as `%D' here", x);
	    }
	  if (DECL_ASSEMBLER_NAME (fn)==DECL_ASSEMBLER_NAME (x))
	    {
	      /* We complain about multiple destructors on sight,
		 so we do not repeat the warning here.  Friend-friend
		 ambiguities are warned about outside this loop.  */
	      if (!DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (fn)))
		cp_error_at ("ambiguous method `%#D' in structure", fn);
	      break;
	    }
	  prev_x = x;
	}
      if (x == 0)
	{
	  if (*testp)
	    DECL_CHAIN (prev_x) = fn;
	  else
	    *testp = fn;
	}
    }
  else
    {
      obstack_ptr_grow (&class_obstack, fn);
      *method_vec_ptr = (tree)obstack_base (&class_obstack);
    }
}

/* Warn about duplicate methods in fn_fields.  Also compact method
   lists so that lookup can be made faster.

   Algorithm: Outer loop builds lists by method name.  Inner loop
   checks for redundant method names within a list.

   Data Structure: List of method lists.  The outer list is a
   TREE_LIST, whose TREE_PURPOSE field is the field name and the
   TREE_VALUE is the DECL_CHAIN of the FUNCTION_DECLs.  TREE_CHAIN
   links the entire list of methods for TYPE_METHODS.  Friends are
   chained in the same way as member functions (? TREE_CHAIN or
   DECL_CHAIN), but they live in the TREE_TYPE field of the outer
   list.  That allows them to be quickly deleted, and requires no
   extra storage.

   If there are any constructors/destructors, they are moved to the
   front of the list.  This makes pushclass more efficient.

   We also link each field which has shares a name with its baseclass
   to the head of the list of fields for that base class.  This allows
   us to reduce search time in places like `build_method_call' to
   consider only reasonably likely functions.  */

static tree
finish_struct_methods (t, fn_fields, nonprivate_method)
     tree t;
     tree fn_fields;
     int nonprivate_method;
{
  tree method_vec;
  tree save_fn_fields = tree_cons (NULL_TREE, NULL_TREE, fn_fields);
  tree lastp;
  tree name = constructor_name (t);
  int i, n_baseclasses = CLASSTYPE_N_BASECLASSES (t);

  /* Now prepare to gather fn_fields into vector.  */
  struct obstack *ambient_obstack = current_obstack;
  current_obstack = &class_obstack;
  method_vec = make_node (TREE_VEC);
  /* Room has been saved for constructors and destructors.  */
  current_obstack = ambient_obstack;
  /* Now make this a live vector.  */
  obstack_free (&class_obstack, method_vec);
  obstack_blank (&class_obstack, sizeof (struct tree_vec));

  /* First fill in entry 0 with the constructors, and the next few with
     type conversion operators (if any).  */

  for (lastp = save_fn_fields; fn_fields; fn_fields = TREE_CHAIN (lastp))
    {
      tree fn_name = DECL_NAME (fn_fields);
      if (fn_name == NULL_TREE)
	fn_name = name;

      /* Clear out this flag.

	 @@ Doug may figure out how to break
	 @@ this with nested classes and friends.  */
      DECL_IN_AGGR_P (fn_fields) = 0;

      /* Note here that a copy ctor is private, so we don't dare generate
 	 a default copy constructor for a class that has a member
 	 of this type without making sure they have access to it.  */
      if (fn_name == name)
 	{
 	  tree parmtypes = FUNCTION_ARG_CHAIN (fn_fields);
 	  tree parmtype = parmtypes ? TREE_VALUE (parmtypes) : void_type_node;
	  
 	  if (TREE_CODE (parmtype) == REFERENCE_TYPE
 	      && TYPE_MAIN_VARIANT (TREE_TYPE (parmtype)) == t)
 	    {
 	      if (TREE_CHAIN (parmtypes) == NULL_TREE
 		  || TREE_CHAIN (parmtypes) == void_list_node
 		  || TREE_PURPOSE (TREE_CHAIN (parmtypes)))
 		{
 		  if (TREE_PROTECTED (fn_fields))
 		    TYPE_HAS_NONPUBLIC_CTOR (t) = 1;
 		  else if (TREE_PRIVATE (fn_fields))
 		    TYPE_HAS_NONPUBLIC_CTOR (t) = 2;
 		}
 	    }
	  /* Constructors are handled easily in search routines.  */
	  DECL_CHAIN (fn_fields) = TREE_VEC_ELT (method_vec, 0);
	  TREE_VEC_ELT (method_vec, 0) = fn_fields;
 	}
      else if (IDENTIFIER_TYPENAME_P (fn_name))
	{
	  tree return_type = TREE_TYPE (TREE_TYPE (fn_fields));

	  if (typecode_p (return_type, INTEGER_TYPE)
	      || typecode_p (return_type, BOOLEAN_TYPE)
	      || typecode_p (return_type, ENUMERAL_TYPE))
	    TYPE_HAS_INT_CONVERSION (t) = 1;
	  else if (typecode_p (return_type, REAL_TYPE))
	    TYPE_HAS_REAL_CONVERSION (t) = 1;

	  grow_method (fn_fields, &method_vec);
	}
      else
	{
	  lastp = fn_fields;
	  continue;
	}

      TREE_CHAIN (lastp) = TREE_CHAIN (fn_fields);
      TREE_CHAIN (fn_fields) = NULL_TREE;
    }

  fn_fields = TREE_CHAIN (save_fn_fields);
  while (fn_fields)
    {
      tree nextp;
      tree fn_name = DECL_NAME (fn_fields);
      if (fn_name == NULL_TREE)
	fn_name = name;

      nextp = TREE_CHAIN (fn_fields);
      TREE_CHAIN (fn_fields) = NULL_TREE;

      if (fn_name == ansi_opname[(int) MODIFY_EXPR])
	{
	  tree parmtype = TREE_VALUE (FUNCTION_ARG_CHAIN (fn_fields));

	  if (copy_assignment_arg_p (parmtype, DECL_VIRTUAL_P (fn_fields)))
	    {
	      if (TREE_PROTECTED (fn_fields))
		TYPE_HAS_NONPUBLIC_ASSIGN_REF (t) = 1;
	      else if (TREE_PRIVATE (fn_fields))
		TYPE_HAS_NONPUBLIC_ASSIGN_REF (t) = 2;
	    }
	}

      grow_method (fn_fields, &method_vec);
      fn_fields = nextp;
    }

  TREE_VEC_LENGTH (method_vec) = (tree *)obstack_next_free (&class_obstack)
    - (&TREE_VEC_ELT (method_vec, 0));
  obstack_finish (&class_obstack);
  CLASSTYPE_METHOD_VEC (t) = method_vec;

  if (nonprivate_method == 0
      && CLASSTYPE_FRIEND_CLASSES (t) == NULL_TREE
      && DECL_FRIENDLIST (TYPE_NAME (t)) == NULL_TREE)
    {
      tree binfos = BINFO_BASETYPES (TYPE_BINFO (t));
      for (i = 0; i < n_baseclasses; i++)
	if (TREE_VIA_PUBLIC (TREE_VEC_ELT (binfos, i))
	    || TREE_VIA_PROTECTED (TREE_VEC_ELT (binfos, i)))
	  {
	    nonprivate_method = 1;
	    break;
	  }
      if (nonprivate_method == 0)
	cp_warning ("all member functions in class `%T' are private", t);
    }

  /* If there are constructors (and destructors), they are at the
     front.  Place destructors at very front.  Also warn if all
     constructors and/or destructors are private (in which case this
     class is effectively unusable.  */
  if (TYPE_HAS_DESTRUCTOR (t))
    {
      tree dtor, prev;

      for (dtor = TREE_VEC_ELT (method_vec, 0);
	   dtor;
	   prev = dtor, dtor = DECL_CHAIN (dtor))
	{
	  if (DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (dtor)))
	    {
	      if (TREE_PRIVATE (dtor)
		  && CLASSTYPE_FRIEND_CLASSES (t) == NULL_TREE
		  && DECL_FRIENDLIST (TYPE_NAME (t)) == NULL_TREE
		  && warn_ctor_dtor_privacy)
		cp_warning ("`%#T' only defines a private destructor and has no friends",
			    t);
	      break;
	    }
	}

      /* Wild parse errors can cause this to happen.  */
      if (dtor == NULL_TREE)
	TYPE_HAS_DESTRUCTOR (t) = 0;
      else if (dtor != TREE_VEC_ELT (method_vec, 0))
	{
	  DECL_CHAIN (prev) = DECL_CHAIN (dtor);
	  DECL_CHAIN (dtor) = TREE_VEC_ELT (method_vec, 0);
	  TREE_VEC_ELT (method_vec, 0) = dtor;
	}
    }

  /* Now for each member function (except for constructors and
     destructors), compute where member functions of the same
     name reside in base classes.  */
  if (n_baseclasses != 0
      && TREE_VEC_LENGTH (method_vec) > 1)
    {
      int len = TREE_VEC_LENGTH (method_vec);
      tree baselink_vec = make_tree_vec (len);
      int any_links = 0;
      tree baselink_binfo = build_tree_list (NULL_TREE, TYPE_BINFO (t));

      for (i = 1; i < len; i++)
	{
	  TREE_VEC_ELT (baselink_vec, i)
	    = get_baselinks (baselink_binfo, t, DECL_NAME (TREE_VEC_ELT (method_vec, i)));
	  if (TREE_VEC_ELT (baselink_vec, i) != 0)
	    any_links = 1;
	}
      if (any_links != 0)
	CLASSTYPE_BASELINK_VEC (t) = baselink_vec;
      else
	obstack_free (current_obstack, baselink_vec);
    }

  /* Now add the methods to the TYPE_METHODS of T, arranged in a chain.  */
  {
    tree x, last_x = NULL_TREE;
    int limit = TREE_VEC_LENGTH (method_vec);

    for (i = 1; i < limit; i++)
      {
	for (x = TREE_VEC_ELT (method_vec, i); x; x = DECL_CHAIN (x))
	  {
	    if (last_x != NULL_TREE)
	      TREE_CHAIN (last_x) = x;
	    last_x = x;
	  }
      }

    /* Put ctors and dtors at the front of the list.  */
    x = TREE_VEC_ELT (method_vec, 0);
    if (x)
      {
	while (DECL_CHAIN (x))
	  {
	    /* Let's avoid being circular about this.  */
	    if (x == DECL_CHAIN (x))
	      break;
	    TREE_CHAIN (x) = DECL_CHAIN (x);
	    x = DECL_CHAIN (x);
	  }
	if (TREE_VEC_LENGTH (method_vec) > 1)
	  TREE_CHAIN (x) = TREE_VEC_ELT (method_vec, 1);
	else
	  TREE_CHAIN (x) = NULL_TREE;
      }
  }

  TYPE_METHODS (t) = method_vec;

  return method_vec;
}

/* Emit error when a duplicate definition of a type is seen.  Patch up. */

void
duplicate_tag_error (t)
     tree t;
{
  cp_error ("redefinition of `%#T'", t);
  cp_error_at ("previous definition here", t);

  /* Pretend we haven't defined this type.  */

  /* All of the component_decl's were TREE_CHAINed together in the parser.
     finish_struct_methods walks these chains and assembles all methods with
     the same base name into DECL_CHAINs. Now we don't need the parser chains
     anymore, so we unravel them.
   */
  /*
   * This used to be in finish_struct, but it turns out that the
   * TREE_CHAIN is used by dbxout_type_methods and perhaps some other things...
   */
  if (CLASSTYPE_METHOD_VEC(t)) 
    {
      tree tv = CLASSTYPE_METHOD_VEC(t);
      int i, len  = TREE_VEC_LENGTH (tv);
      for (i = 0; i < len; i++)
	{
	  tree unchain = TREE_VEC_ELT (tv, i);
	  while (unchain != NULL_TREE) 
	    {
	      TREE_CHAIN (unchain) = NULL_TREE;
	      unchain = DECL_CHAIN(unchain);
	    }
	}
    }

  if (TYPE_LANG_SPECIFIC (t))
    {
      tree as_list = CLASSTYPE_AS_LIST (t);
      tree binfo = TYPE_BINFO (t);
      tree binfo_as_list = CLASSTYPE_BINFO_AS_LIST (t);
      int interface_only = CLASSTYPE_INTERFACE_ONLY (t);
      int interface_unknown = CLASSTYPE_INTERFACE_UNKNOWN (t);

      bzero ((char *) TYPE_LANG_SPECIFIC (t), sizeof (struct lang_type));
      BINFO_BASETYPES(binfo) = NULL_TREE;

      CLASSTYPE_AS_LIST (t) = as_list;
      TYPE_BINFO (t) = binfo;
      CLASSTYPE_BINFO_AS_LIST (t) = binfo_as_list;
      CLASSTYPE_INTERFACE_ONLY (t) = interface_only;
      SET_CLASSTYPE_INTERFACE_UNKNOWN_X (t, interface_unknown);
      CLASSTYPE_VBASE_SIZE (t) = integer_zero_node;
      TYPE_REDEFINED (t) = 1;
    }
  TYPE_SIZE (t)