semantics.c

gcc-2.95.3 Linux下最常用的C编译器

tree 
begin_constructor_declarator (scope, name)
     tree scope;
     tree name;
{
  tree result = build_parse_node (SCOPE_REF, scope, name);
  enter_scope_of (result);
  return result;
}

/* Finish an init-declarator.  Returns a DECL.  */

tree
finish_declarator (declarator, declspecs, attributes,
		   prefix_attributes, initialized)
     tree declarator;
     tree declspecs;
     tree attributes;
     tree prefix_attributes;
     int initialized;
{
  return start_decl (declarator, declspecs, initialized, attributes,
		     prefix_attributes); 
}

/* Finish a translation unit.  */

void 
finish_translation_unit ()
{
  /* In case there were missing closebraces,
     get us back to the global binding level.  */
  while (! toplevel_bindings_p ())
    poplevel (0, 0, 0);
  while (current_namespace != global_namespace)
    pop_namespace ();
  finish_file ();
}

/* Finish a template type parameter, specified as AGGR IDENTIFIER.
   Returns the parameter.  */

tree 
finish_template_type_parm (aggr, identifier)
     tree aggr;
     tree identifier;
{
  if (aggr == signature_type_node)
    sorry ("signature as template type parameter");
  else if (aggr != class_type_node)
    {
      pedwarn ("template type parameters must use the keyword `class' or `typename'");
      aggr = class_type_node;
    }

  return build_tree_list (aggr, identifier);
}

/* Finish a template template parameter, specified as AGGR IDENTIFIER.
   Returns the parameter.  */

tree 
finish_template_template_parm (aggr, identifier)
     tree aggr;
     tree identifier;
{
  tree decl = build_decl (TYPE_DECL, identifier, NULL_TREE);
  tree tmpl = build_lang_decl (TEMPLATE_DECL, identifier, NULL_TREE);
  DECL_TEMPLATE_PARMS (tmpl) = current_template_parms;
  DECL_TEMPLATE_RESULT (tmpl) = decl;
  SET_DECL_ARTIFICIAL (decl);
  end_template_decl ();

  return finish_template_type_parm (aggr, tmpl);
}

/* Finish a parameter list, indicated by PARMS.  If ELLIPSIS is
   non-zero, the parameter list was terminated by a `...'.  */

tree
finish_parmlist (parms, ellipsis)
     tree parms;
     int ellipsis;
{
  if (!ellipsis)
    chainon (parms, void_list_node);
  /* We mark the PARMS as a parmlist so that declarator processing can
     disambiguate certain constructs.  */
  if (parms != NULL_TREE)
    TREE_PARMLIST (parms) = 1;

  return parms;
}

/* Begin a class definition, as indicated by T.  */

tree
begin_class_definition (t)
     tree t;
{
  push_obstacks_nochange ();
  end_temporary_allocation ();
  
  if (t == error_mark_node
      || ! IS_AGGR_TYPE (t))
    {
      t = make_lang_type (RECORD_TYPE);
      pushtag (make_anon_name (), t, 0);
    }

  /* In a definition of a member class template, we will get here with an
     implicit typename, a TYPENAME_TYPE with a type.  */
  if (TREE_CODE (t) == TYPENAME_TYPE)
    t = TREE_TYPE (t);
  
  /* If we generated a partial instantiation of this type, but now
     we're seeing a real definition, we're actually looking at a
     partial specialization.  Consider:

       template <class T, class U>
       struct Y {};

       template <class T>
       struct X {};

       template <class T, class U>
       void f()
       {
	 typename X<Y<T, U> >::A a;
       }

       template <class T, class U>
       struct X<Y<T, U> >
       {
       };

     We have to undo the effects of the previous partial
     instantiation.  */
  if (PARTIAL_INSTANTIATION_P (t))
    {
      if (!pedantic) 
	{
	  /* Unfortunately, when we're not in pedantic mode, we
	     attempt to actually fill in some of the fields of the
	     partial instantiation, in order to support the implicit
	     typename extension.  Clear those fields now, in
	     preparation for the definition here.  The fields cleared
	     here must match those set in instantiate_class_template.
	     Look for a comment mentioning begin_class_definition
	     there.  */
	  TYPE_BINFO_BASETYPES (t) = NULL_TREE;
	  TYPE_FIELDS (t) = NULL_TREE;
	  TYPE_METHODS (t) = NULL_TREE;
	  CLASSTYPE_TAGS (t) = NULL_TREE;
	  TYPE_SIZE (t) = NULL_TREE;
	}

      /* This isn't a partial instantiation any more.  */
      PARTIAL_INSTANTIATION_P (t) = 0;
    }
  /* If this type was already complete, and we see another definition,
     that's an error.  */
  else if (TYPE_SIZE (t))
    duplicate_tag_error (t);

  if (TYPE_BEING_DEFINED (t))
    {
      t = make_lang_type (TREE_CODE (t));
      pushtag (TYPE_IDENTIFIER (t), t, 0);
    }
  maybe_process_partial_specialization (t);
  pushclass (t, 1);
  TYPE_BEING_DEFINED (t) = 1;
  /* Reset the interface data, at the earliest possible
     moment, as it might have been set via a class foo;
     before.  */
  /* Don't change signatures.  */
  if (! IS_SIGNATURE (t))
    {
      int needs_writing;
      tree name = TYPE_IDENTIFIER (t);
      
      if (! ANON_AGGRNAME_P (name))
	{
	  CLASSTYPE_INTERFACE_ONLY (t) = interface_only;
	  SET_CLASSTYPE_INTERFACE_UNKNOWN_X
	    (t, interface_unknown);
	}
      
      /* Record how to set the access of this class's
	 virtual functions.  If write_virtuals == 3, then
	 inline virtuals are ``extern inline''.  */
      if (write_virtuals == 3)
	needs_writing = ! CLASSTYPE_INTERFACE_ONLY (t)
	  && CLASSTYPE_INTERFACE_KNOWN (t);
      else
	needs_writing = 1;
      CLASSTYPE_VTABLE_NEEDS_WRITING (t) = needs_writing;
    }
#if 0
  tmp = TYPE_IDENTIFIER ($<ttype>0);
  if (tmp && IDENTIFIER_TEMPLATE (tmp))
    overload_template_name (tmp, 1);
#endif
  reset_specialization();
  
  /* In case this is a local class within a template
     function, we save the current tree structure so
     that we can get it back later.  */
  begin_tree ();

  /* Make a declaration for this class in its own scope.  */
  build_self_reference ();

  return t;
}

/* Finish the member declaration given by DECL.  */

void
finish_member_declaration (decl)
     tree decl;
{
  if (decl == error_mark_node || decl == NULL_TREE)
    return;

  if (decl == void_type_node)
    /* The COMPONENT was a friend, not a member, and so there's
       nothing for us to do.  */
    return;

  /* We should see only one DECL at a time.  */
  my_friendly_assert (TREE_CHAIN (decl) == NULL_TREE, 0);

  /* Set up access control for DECL.  */
  TREE_PRIVATE (decl) 
    = (current_access_specifier == access_private_node);
  TREE_PROTECTED (decl) 
    = (current_access_specifier == access_protected_node);
  if (TREE_CODE (decl) == TEMPLATE_DECL)
    {
      TREE_PRIVATE (DECL_RESULT (decl)) = TREE_PRIVATE (decl);
      TREE_PROTECTED (DECL_RESULT (decl)) = TREE_PROTECTED (decl);
    }

  /* Mark the DECL as a member of the current class.  */
  if (TREE_CODE (decl) == FUNCTION_DECL 
      || DECL_FUNCTION_TEMPLATE_P (decl))
    /* Historically, DECL_CONTEXT was not set for a FUNCTION_DECL in
       finish_struct.  Presumably it is already set as the function is
       parsed.  Perhaps DECL_CLASS_CONTEXT is already set, too?  */
    DECL_CLASS_CONTEXT (decl) = current_class_type;
  else
    DECL_CONTEXT (decl) = current_class_type;

  /* Put functions on the TYPE_METHODS list and everything else on the
     TYPE_FIELDS list.  Note that these are built up in reverse order.
     We reverse them (to obtain declaration order) in finish_struct.  */
  if (TREE_CODE (decl) == FUNCTION_DECL 
      || DECL_FUNCTION_TEMPLATE_P (decl))
    {
      /* We also need to add this function to the
	 CLASSTYPE_METHOD_VEC.  */
      add_method (current_class_type, 0, decl);

      TREE_CHAIN (decl) = TYPE_METHODS (current_class_type);
      TYPE_METHODS (current_class_type) = decl;
    }
  else
    {
      /* All TYPE_DECLs go at the end of TYPE_FIELDS.  Ordinary fields
	 go at the beginning.  The reason is that lookup_field_1
	 searches the list in order, and we want a field name to
	 override a type name so that the "struct stat hack" will
	 work.  In particular:

	   struct S { enum E { }; int E } s;
	   s.E = 3;

	 is legal.  In addition, the FIELD_DECLs must be maintained in
	 declaration order so that class layout works as expected.
	 However, we don't need that order until class layout, so we
	 save a little time by putting FIELD_DECLs on in reverse order
	 here, and then reversing them in finish_struct_1.  (We could
	 also keep a pointer to the correct insertion points in the
	 list.)  */

      if (TREE_CODE (decl) == TYPE_DECL)
	TYPE_FIELDS (current_class_type) 
	  = chainon (TYPE_FIELDS (current_class_type), decl);
      else
	{
	  TREE_CHAIN (decl) = TYPE_FIELDS (current_class_type);
	  TYPE_FIELDS (current_class_type) = decl;
	}

      /* Enter the DECL into the scope of the class.  */
      if (TREE_CODE (decl) != USING_DECL)
	pushdecl_class_level (decl);
    }
}

/* Finish a class definition T with the indicate ATTRIBUTES.  If SEMI,
   the definition is immediately followed by a semicolon.  Returns the
   type.  */

tree
finish_class_definition (t, attributes, semi, pop_scope_p)
     tree t;
     tree attributes;
     int semi;
     int pop_scope_p;
{
  /* finish_struct nukes this anyway; if finish_exception does too,
     then it can go.  */
  if (semi)
    note_got_semicolon (t);

  /* If we got any attributes in class_head, xref_tag will stick them in
     TREE_TYPE of the type.  Grab them now.  */
  attributes = chainon (TREE_TYPE (t), attributes);
  TREE_TYPE (t) = NULL_TREE;

  if (TREE_CODE (t) == ENUMERAL_TYPE)
    ;
  else
    {
      t = finish_struct (t, attributes, semi);
      if (semi) 
	note_got_semicolon (t);
    }

  pop_obstacks ();

  if (! semi)
    check_for_missing_semicolon (t); 
  if (pop_scope_p)
    pop_scope (CP_DECL_CONTEXT (TYPE_MAIN_DECL (t)));
  if (current_scope () == current_function_decl)
    do_pending_defargs ();

  return t;
}

/* Finish processing the default argument expressions cached during
   the processing of a class definition.  */

void
begin_inline_definitions ()
{
  if (pending_inlines 
      && current_scope () == current_function_decl)
    do_pending_inlines ();
}

/* Finish processing the inline function definitions cached during the
   processing of a class definition.  */

void
finish_inline_definitions ()
{
  if (current_class_type == NULL_TREE)
    clear_inline_text_obstack (); 
  
  /* Undo the begin_tree in begin_class_definition.  */
  end_tree ();
}

/* Finish processing the declaration of a member class template
   TYPES whose template parameters are given by PARMS.  */

tree
finish_member_class_template (types)
     tree types;
{
  tree t;

  /* If there are declared, but undefined, partial specializations
     mixed in with the typespecs they will not yet have passed through
     maybe_process_partial_specialization, so we do that here.  */
  for (t = types; t != NULL_TREE; t = TREE_CHAIN (t))
    if (IS_AGGR_TYPE_CODE (TREE_CODE (TREE_VALUE (t))))
      maybe_process_partial_specialization (TREE_VALUE (t));

  note_list_got_semicolon (types);
  grok_x_components (types);
  if (TYPE_CONTEXT (TREE_VALUE (types)) != current_class_type)
    /* The component was in fact a friend declaration.  We avoid
       finish_member_template_decl performing certain checks by
       unsetting TYPES.  */
    types = NULL_TREE;
  
  finish_member_template_decl (types);

  /* As with other component type declarations, we do
     not store the new DECL on the list of
     component_decls.  */
  return NULL_TREE;
}

/* Finish processsing a complete template declaration.  The PARMS are
   the template parameters.  */

void
finish_template_decl (parms)
     tree parms;
{
  if (parms)
    end_template_decl ();
  else
    end_specialization ();
}

/* Finish processing a a template-id (which names a type) of the form
   NAME < ARGS >.  Return the TYPE_DECL for the type named by the
   template-id.  If ENTERING_SCOPE is non-zero we are about to enter
   the scope of template-id indicated.  */

tree
finish_template_type (name, args, entering_scope)
     tree name;
     tree args;
     int entering_scope;
{
  tree decl;

  decl = lookup_template_class (name, args,
				NULL_TREE, NULL_TREE, entering_scope);
  if (decl != error_mark_node)
    decl = TYPE_STUB_DECL (decl);

  return decl;
}

/* SR is a SCOPE_REF node.  Enter the scope of SR, whether it is a
   namespace scope or a class scope.  */

void
enter_scope_of (sr)
     tree sr;
{
  tree scope = TREE_OPERAND (sr, 0);

  if (TREE_CODE (scope) == NAMESPACE_DECL)
    {
      push_decl_namespace (scope);
      TREE_COMPLEXITY (sr) = -1;
    }
  else if (scope != current_class_type)
    {
      if (TREE_CODE (scope) == TYPENAME_TYPE)
	{
	  /* In a declarator for a template class member, the scope will
	     get here as an implicit typename, a TYPENAME_TYPE with a type.  */
	  scope = TREE_TYPE (scope);
	  TREE_OPERAND (sr, 0) = scope;
	}
      push_nested_class (scope, 3);
      TREE_COMPLEXITY (sr) = current_class_depth;
    }
}

/* Finish processing a BASE_CLASS with the indicated ACCESS_SPECIFIER.
   Return a TREE_LIST containing the ACCESS_SPECIFIER and the
   BASE_CLASS, or NULL_TREE if an error occurred.  The
   ACCESSS_SPECIFIER is one of
   access_{default,public,protected_private}[_virtual]_node.*/

tree 
finish_base_specifier (access_specifier, base_class,
		       current_aggr_is_signature)
     tree access_specifier;
     tree base_class;
     int current_aggr_is_signature;
{
  tree type;
  tree result;

  if (base_class == NULL_TREE)
    {
      error ("invalid base class");
      type = error_mark_node;
    }
  else
    type = TREE_TYPE (base_class);
  if (current_aggr_is_signature && access_specifier)
    error ("access and source specifiers not allowed in signature");
  if (! is_aggr_type (type, 1))
    result = NULL_TREE;
  else if (current_aggr_is_signature
	   && (! type) && (! IS_SIGNATURE (type)))
    {
      error ("class name not allowed as base signature");
      result = NULL_TREE;
    }
  else if (current_aggr_is_signature)
    {
      sorry ("signature inheritance, base type `%s' ignored",
	     IDENTIFIER_POINTER (access_specifier));
      result = build_tree_list (access_public_node, type);
    }
  else if (type && IS_SIGNATURE (type))
    {
      error ("signature name not allowed as base class");
      result = NULL_TREE;
    }
  else
    result = build_tree_list (access_specifier, type);

  return result;
}

/* Called when multiple declarators are processed.  If that is not
   premitted in this context, an error is issued.  */

void
check_multiple_declarators ()
{
  /* [temp]
     
     In a template-declaration, explicit specialization, or explicit
     instantiation the init-declarator-list in the declaration shall
     contain at most one declarator.  

     We don't just use PROCESSING_TEMPLATE_DECL for the first
     condition since that would disallow the perfectly legal code, 
     like `template <class T> struct S { int i, j; };'.  */
  tree scope = current_scope ();

  if (scope && TREE_CODE (scope) == FUNCTION_DECL)
    /* It's OK to write `template <class T> void f() { int i, j;}'.  */
    return;
     
  if (PROCESSING_REAL_TEMPLATE_DECL_P () 
      || processing_explicit_instantiation
      || processing_specialization)
    cp_error ("multiple declarators in template declaration");
}

tree
finish_typeof (expr)
     tree expr;
{
  if (processing_template_decl)
    {
      tree t;

      push_obstacks_nochange ();
      end_temporary_allocation ();

      t = make_lang_type (TYPEOF_TYPE);
      TYPE_FIELDS (t) = expr;

      pop_obstacks ();

      return t;
    }

  return TREE_TYPE (expr);
}