decl.c

GCC编译器源代码

    {
      if (DECL_NAME (link) != NULL_TREE)
	{
	  /* If the ident. was used or addressed via a local extern decl,
	     don't forget that fact.  */
	  if (DECL_EXTERNAL (link))
	    {
	      if (TREE_USED (link))
		TREE_USED (DECL_ASSEMBLER_NAME (link)) = 1;
	      if (TREE_ADDRESSABLE (link))
		TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (link)) = 1;
	    }
	  IDENTIFIER_LOCAL_VALUE (DECL_NAME (link)) = NULL_TREE;
	}
    }

  /* Restore all name-meanings of the outer levels
     that were shadowed by this level.  */

  for (link = current_binding_level->shadowed; link; link = TREE_CHAIN (link))
    IDENTIFIER_LOCAL_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);
  for (link = current_binding_level->class_shadowed;
       link; link = TREE_CHAIN (link))
    IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);
  for (link = current_binding_level->type_shadowed;
       link; link = TREE_CHAIN (link))
    IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);

  /* suspend a level.  */
  suspend_binding_level ();
#endif
}

/* Subroutines for reverting temporarily to top-level for instantiation
   of templates and such.  We actually need to clear out the class- and
   local-value slots of all identifiers, so that only the global values
   are at all visible.  Simply setting current_binding_level to the global
   scope isn't enough, because more binding levels may be pushed.  */
struct saved_scope {
  struct binding_level *old_binding_level;
  tree old_bindings;
  struct saved_scope *prev;
  tree class_name, class_type, function_decl;
  struct binding_level *class_bindings;
  tree *lang_base, *lang_stack, lang_name;
  int lang_stacksize;
  int minimal_parse_mode;
  tree last_function_parms;
  tree template_parms;
  HOST_WIDE_INT processing_template_decl;
  tree previous_class_type, previous_class_values;
};
static struct saved_scope *current_saved_scope;

static tree
store_bindings (names, old_bindings)
     tree names, old_bindings;
{
  tree t;
  for (t = names; t; t = TREE_CHAIN (t))
    {
      tree binding, t1, id;

      if (TREE_CODE (t) == TREE_LIST)
	id = TREE_PURPOSE (t);
      else
	id = DECL_NAME (t);

      if (!id
	  || (!IDENTIFIER_LOCAL_VALUE (id)
	      && !IDENTIFIER_CLASS_VALUE (id)))
	continue;

      for (t1 = old_bindings; t1; t1 = TREE_CHAIN (t1))
	if (TREE_VEC_ELT (t1, 0) == id)
	  goto skip_it;
	    
      binding = make_tree_vec (4);
      if (id)
	{
	  my_friendly_assert (TREE_CODE (id) == IDENTIFIER_NODE, 135);
	  TREE_VEC_ELT (binding, 0) = id;
	  TREE_VEC_ELT (binding, 1) = IDENTIFIER_TYPE_VALUE (id);
	  TREE_VEC_ELT (binding, 2) = IDENTIFIER_LOCAL_VALUE (id);
	  TREE_VEC_ELT (binding, 3) = IDENTIFIER_CLASS_VALUE (id);
	  IDENTIFIER_LOCAL_VALUE (id) = NULL_TREE;
	  IDENTIFIER_CLASS_VALUE (id) = NULL_TREE;
	}
      TREE_CHAIN (binding) = old_bindings;
      old_bindings = binding;
    skip_it:
      ;
    }
  return old_bindings;
}

void
maybe_push_to_top_level (pseudo)
     int pseudo;
{
  extern int current_lang_stacksize;
  struct saved_scope *s
    = (struct saved_scope *) xmalloc (sizeof (struct saved_scope));
  struct binding_level *b = inner_binding_level;
  tree old_bindings = NULL_TREE;

  if (current_function_decl)
    push_cp_function_context (NULL_TREE);

  if (previous_class_type)
    old_bindings = store_bindings (previous_class_values, old_bindings);

  /* Have to include global_binding_level, because class-level decls
     aren't listed anywhere useful.  */
  for (; b; b = b->level_chain)
    {
      tree t;

      if (b == global_binding_level || (pseudo && b->pseudo_global))
	break;

      old_bindings = store_bindings (b->names, old_bindings);
      /* We also need to check class_shadowed to save class-level type
	 bindings, since pushclass doesn't fill in b->names.  */
      if (b->parm_flag == 2)
	old_bindings = store_bindings (b->class_shadowed, old_bindings);

      /* Unwind type-value slots back to top level.  */
      for (t = b->type_shadowed; t; t = TREE_CHAIN (t))
	SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (t), TREE_VALUE (t));
    }

  s->old_binding_level = current_binding_level;
  current_binding_level = b;

  s->class_name = current_class_name;
  s->class_type = current_class_type;
  s->function_decl = current_function_decl;
  s->class_bindings = class_binding_level;
  s->lang_stack = current_lang_stack;
  s->lang_base = current_lang_base;
  s->lang_stacksize = current_lang_stacksize;
  s->lang_name = current_lang_name;
  s->minimal_parse_mode = minimal_parse_mode;
  s->last_function_parms = last_function_parms;
  s->template_parms = current_template_parms;
  s->processing_template_decl = processing_template_decl;
  s->previous_class_type = previous_class_type;
  s->previous_class_values = previous_class_values;

  current_class_name = current_class_type = NULL_TREE;
  current_function_decl = NULL_TREE;
  class_binding_level = (struct binding_level *)0;
  current_lang_stacksize = 10;
  current_lang_stack = current_lang_base
    = (tree *) xmalloc (current_lang_stacksize * sizeof (tree));
  current_lang_name = lang_name_cplusplus;
  strict_prototype = strict_prototypes_lang_cplusplus;
  named_labels = NULL_TREE;
  minimal_parse_mode = 0;
  previous_class_type = previous_class_values = NULL_TREE;
  if (!pseudo)
    {
      current_template_parms = NULL_TREE;
      processing_template_decl = 0;
    }

  s->prev = current_saved_scope;
  s->old_bindings = old_bindings;
  current_saved_scope = s;

  push_obstacks (&permanent_obstack, &permanent_obstack);
}

void
push_to_top_level ()
{
  maybe_push_to_top_level (0);
}

void
pop_from_top_level ()
{
  extern int current_lang_stacksize;
  struct saved_scope *s = current_saved_scope;
  tree t;

  /* Clear out class-level bindings cache.  */
  if (previous_class_type)
    {
      popclass (-1);
      previous_class_type = NULL_TREE;
    }

  pop_obstacks ();

  current_binding_level = s->old_binding_level;
  current_saved_scope = s->prev;
  for (t = s->old_bindings; t; t = TREE_CHAIN (t))
    {
      tree id = TREE_VEC_ELT (t, 0);
      if (id)
	{
	  IDENTIFIER_TYPE_VALUE (id) = TREE_VEC_ELT (t, 1);
	  IDENTIFIER_LOCAL_VALUE (id) = TREE_VEC_ELT (t, 2);
	  IDENTIFIER_CLASS_VALUE (id) = TREE_VEC_ELT (t, 3);
	}
    }
  current_class_name = s->class_name;
  current_class_type = s->class_type;
  current_function_decl = s->function_decl;
  class_binding_level = s->class_bindings;
  free (current_lang_base);
  current_lang_base = s->lang_base;
  current_lang_stack = s->lang_stack;
  current_lang_name = s->lang_name;
  current_lang_stacksize = s->lang_stacksize;
  if (current_lang_name == lang_name_cplusplus)
    strict_prototype = strict_prototypes_lang_cplusplus;
  else if (current_lang_name == lang_name_c)
    strict_prototype = strict_prototypes_lang_c;
  minimal_parse_mode = s->minimal_parse_mode;
  last_function_parms = s->last_function_parms;
  current_template_parms = s->template_parms;
  processing_template_decl = s->processing_template_decl;
  previous_class_type = s->previous_class_type;
  previous_class_values = s->previous_class_values;

  free (s);

  if (current_function_decl)
    pop_cp_function_context (NULL_TREE);
}

/* Push a definition of struct, union or enum tag "name".
   into binding_level "b".   "type" should be the type node, 
   We assume that the tag "name" is not already defined.

   Note that the definition may really be just a forward reference.
   In that case, the TYPE_SIZE will be a NULL_TREE.

   C++ gratuitously puts all these tags in the name space.  */

/* When setting the IDENTIFIER_TYPE_VALUE field of an identifier ID,
   record the shadowed value for this binding contour.  TYPE is
   the type that ID maps to.  */

static void
set_identifier_type_value_with_scope (id, type, b)
     tree id;
     tree type;
     struct binding_level *b;
{
  if (b != global_binding_level)
    {
      tree old_type_value = IDENTIFIER_TYPE_VALUE (id);
      b->type_shadowed
	= tree_cons (id, old_type_value, b->type_shadowed);
    }
  SET_IDENTIFIER_TYPE_VALUE (id, type);
}

/* As set_identifier_type_value_with_scope, but using inner_binding_level.  */

void
set_identifier_type_value (id, type)
     tree id;
     tree type;
{
  set_identifier_type_value_with_scope (id, type, inner_binding_level);
}

/* Pop off extraneous binding levels left over due to syntax errors.

   We don't pop past namespaces, as they might be valid.  */

void
pop_everything ()
{
#ifdef DEBUG_CP_BINDING_LEVELS
  fprintf (stderr, "XXX entering pop_everything ()\n");
#endif
  while (! toplevel_bindings_p () && ! pseudo_global_level_p ())
    {
      if (class_binding_level)
	pop_nested_class (1);
      else
	poplevel (0, 0, 0);
    }
#ifdef DEBUG_CP_BINDING_LEVELS
  fprintf (stderr, "XXX leaving pop_everything ()\n");
#endif
}

/* Push a tag name NAME for struct/class/union/enum type TYPE.
   Normally put into into the inner-most non-tag-transparent scope,
   but if GLOBALIZE is true, put it in the inner-most non-class scope.
   The latter is needed for implicit declarations.  */

void
pushtag (name, type, globalize)
     tree name, type;
     int globalize;
{
  register struct binding_level *b;
  tree context = 0;
  tree c_decl = 0;

  b = inner_binding_level;
  while (b->tag_transparent
	 || (globalize && b->parm_flag == 2))
    b = b->level_chain;

  if (toplevel_bindings_p ())
    b->tags = perm_tree_cons (name, type, b->tags);
  else
    b->tags = saveable_tree_cons (name, type, b->tags);

  if (name)
    {
      context = type ? TYPE_CONTEXT (type) : NULL_TREE;
      if (! context && ! globalize)
        context = current_scope ();
      if (context)
	c_decl = TREE_CODE (context) == FUNCTION_DECL
	  ? context : TYPE_MAIN_DECL (context);

      /* Do C++ gratuitous typedefing.  */
      if (IDENTIFIER_TYPE_VALUE (name) != type)
        {
          register tree d;
	  int newdecl = 0;
	  
	  if (b->parm_flag != 2
	      || TYPE_SIZE (current_class_type) != NULL_TREE)
	    {
	      d = lookup_nested_type (type, c_decl);

	      if (d == NULL_TREE)
		{
		  newdecl = 1;
		  d = build_decl (TYPE_DECL, name, type);
		  SET_DECL_ARTIFICIAL (d);
		  set_identifier_type_value_with_scope (name, type, b);
		}
	      else
		d = TYPE_MAIN_DECL (d);

	      TYPE_NAME (type) = d;
	      DECL_CONTEXT (d) = context;
	      if (! globalize && processing_template_decl && IS_AGGR_TYPE (type))
		push_template_decl (d);

	      if (b->parm_flag == 2)
		d = pushdecl_class_level (d);
	      else
		d = pushdecl_with_scope (d, b);
	    }
	  else
	    {
	      /* Make nested declarations go into class-level scope.  */
	      newdecl = 1;
	      d = build_decl (TYPE_DECL, name, type);
	      SET_DECL_ARTIFICIAL (d);
	      TYPE_NAME (type) = d;
	      DECL_CONTEXT (d) = context;
	      if (! globalize && processing_template_decl && IS_AGGR_TYPE (type))
		push_template_decl (d);

	      d = pushdecl_class_level (d);
	    }
	  if (newdecl)
	    {
	      if (ANON_AGGRNAME_P (name))
		DECL_IGNORED_P (d) = 1;

	      TYPE_CONTEXT (type) = DECL_CONTEXT (d);
	      DECL_ASSEMBLER_NAME (d) = DECL_NAME (d);
	      DECL_ASSEMBLER_NAME (d)
		= get_identifier (build_overload_name (type, 1, 1));
	    }
        }
      if (b->parm_flag == 2)
	{
	  TREE_NONLOCAL_FLAG (type) = 1;
	  if (TYPE_SIZE (current_class_type) == NULL_TREE)
	    CLASSTYPE_TAGS (current_class_type) = b->tags;
	}
    }

  if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL)
    /* Use the canonical TYPE_DECL for this node.  */
    TYPE_STUB_DECL (type) = TYPE_NAME (type);
  else
    {
      /* Create a fake NULL-named TYPE_DECL node whose TREE_TYPE
	 will be the tagged type we just added to the current
	 binding level.  This fake NULL-named TYPE_DECL node helps
	 dwarfout.c to know when it needs to output a
	 representation of a tagged type, and it also gives us a
	 convenient place to record the "scope start" address for
	 the tagged type.  */

      tree d = build_decl (TYPE_DECL, NULL_TREE, type);
      TYPE_STUB_DECL (type) = pushdecl_with_scope (d, b);
    }
}

/* Counter used to create anonymous type names.  */

static int anon_cnt = 0;

/* Return an IDENTIFIER which can be used as a name for
   anonymous structs and unions.  */

tree
make_anon_name ()
{
  char buf[32];

  sprintf (buf, ANON_AGGRNAME_FORMAT, anon_cnt++);
  return get_identifier (buf);
}

/* Clear the TREE_PURPOSE slot of tags which have anonymous typenames.
   This keeps dbxout from getting confused.  */

void
clear_anon_tags ()
{
  register struct binding_level *b;
  register tree tags;
  static int last_cnt = 0;

  /* Fast out if no new anon names were declared.  */
  if (last_cnt == anon_cnt)
    return;

  b = current_binding_level;
  while (b->tag_transparent)
    b = b->level_chain;
  tags = b->tags;
  while (tags)
    {
      /* A NULL purpose means we have already processed all tags
	 from here to the end