decl.c

GUN开源阻止下的编译器GCC

  /* Just in case we get out of sync. */
  if (! namespace_bindings_p ())
    poplevel (0, 0, 0);

  decls = current_binding_level->names;

  /* Clear out the meanings of the local variables of this level.  */

  for (link = decls; link; link = TREE_CHAIN (link))
    {
      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 ();
}

/* 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;
  tree base_init_list, member_init_list;
  struct binding_level *class_bindings;
  tree previous_class_type;
  tree *lang_base, *lang_stack, lang_name;
  int lang_stacksize;
  tree named_labels;
};
static struct saved_scope *current_saved_scope;
extern tree prev_class_type;

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

  /* 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)
	continue;
      
      for (t = b->names; t; t = TREE_CHAIN (t))
	{
	  tree binding, t1, t2 = t;
	  tree id = DECL_ASSEMBLER_NAME (t2);

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

  s->old_binding_level = current_binding_level;
  current_binding_level = global_binding_level;

  s->class_name = current_class_name;
  s->class_type = current_class_type;
  s->function_decl = current_function_decl;
  s->base_init_list = current_base_init_list;
  s->member_init_list = current_member_init_list;
  s->class_bindings = class_binding_level;
  s->previous_class_type = previous_class_type;
  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->named_labels = named_labels;
  current_class_name = current_class_type = NULL_TREE;
  current_function_decl = NULL_TREE;
  class_binding_level = (struct binding_level *)0;
  previous_class_type = NULL_TREE;
  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;

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

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

  if (previous_class_type)
    previous_class_type = NULL_TREE;

  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_base_init_list = s->base_init_list;
  current_member_init_list = s->member_init_list;
  current_function_decl = s->function_decl;
  class_binding_level = s->class_bindings;
  previous_class_type = s->previous_class_type;
  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;
  named_labels = s->named_labels;

  free (s);
}

/* 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);
}

/* Subroutine "set_nested_typename" builds the nested-typename of
   the type decl in question.  (Argument CLASSNAME can actually be
   a function as well, if that's the smallest containing scope.)  */

static void
set_nested_typename (decl, classname, name, type)
     tree decl, classname, name, type;
{
  char *buf;
  my_friendly_assert (TREE_CODE (decl) == TYPE_DECL, 136);

  /* No need to do this for anonymous names, since they're unique.  */
  if (ANON_AGGRNAME_P (name))
    {
      DECL_NESTED_TYPENAME (decl) = name;
      return;
    }

  if (classname == NULL_TREE)
    classname = get_identifier ("");

  my_friendly_assert (TREE_CODE (classname) == IDENTIFIER_NODE, 137);
  my_friendly_assert (TREE_CODE (name) == IDENTIFIER_NODE, 138);
  buf = (char *) alloca (4 + IDENTIFIER_LENGTH (classname)
			 + IDENTIFIER_LENGTH (name));
  sprintf (buf, "%s::%s", IDENTIFIER_POINTER (classname),
	   IDENTIFIER_POINTER (name));
  DECL_NESTED_TYPENAME (decl) = get_identifier (buf);
  TREE_MANGLED (DECL_NESTED_TYPENAME (decl)) = 1;

  /* Create an extra decl so that the nested name will have a type value
     where appropriate.  */
  {
    tree nested, type_decl;
    nested = DECL_NESTED_TYPENAME (decl);
    type_decl = build_decl (TYPE_DECL, nested, type);
    DECL_NESTED_TYPENAME (type_decl) = nested;
    SET_DECL_ARTIFICIAL (type_decl);
    /* Mark the TYPE_DECL node created just above as a gratuitous one so that
       dwarfout.c will know not to generate a TAG_typedef DIE for it, and
       sdbout.c won't try to output a .def for "::foo".  */
    DECL_IGNORED_P (type_decl) = 1;

    /* Remove this when local classes are fixed.  */
    SET_IDENTIFIER_TYPE_VALUE (nested, type);

    pushdecl_nonclass_level (type_decl);
  }
}

/* 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
}

#if 0 /* not yet, should get fixed properly later */
/* Create a TYPE_DECL node with the correct DECL_ASSEMBLER_NAME.
   Other routines shouldn't use build_decl directly; they'll produce
   incorrect results with `-g' unless they duplicate this code.

   This is currently needed mainly for dbxout.c, but we can make
   use of it in method.c later as well.  */
tree
make_type_decl (name, type)
     tree name, type;
{
  tree decl, id;
  decl = build_decl (TYPE_DECL, name, type);
  if (TYPE_NAME (type) == name)
    /* Class/union/enum definition, or a redundant typedef for same.  */
    {
      id = get_identifier (build_overload_name (type, 1, 1));
      DECL_ASSEMBLER_NAME (decl) = id;
    }
  else if (TYPE_NAME (type) != NULL_TREE)
    /* Explicit typedef, or implicit typedef for template expansion.  */
    DECL_ASSEMBLER_NAME (decl) = DECL_ASSEMBLER_NAME (TYPE_NAME (type));
  else
    {
      /* XXX: Typedef for unnamed struct; some other situations.
	 TYPE_NAME is null; what's right here?  */
    }
  return decl;
}
#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);

#if 0
      /* Record the identifier as the type's name if it has none.  */
      if (TYPE_NAME (type) == NULL_TREE)
        TYPE_NAME (type) = name;
#endif
      
      /* 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;
#if 0 /* not yet, should get fixed properly later */
		  d = make_type_decl (name, type);
#else
		  d = build_decl (TYPE_DECL, name, type);
		  DECL_ASSEMBLER_NAME (d) = current_namespace_id (DECL_ASSEMBLER_NAME (d));
#endif
		  SET_DECL_ARTIFICIAL (d);
#ifdef DWARF_DEBUGGING_INFO
		  if (write_symbols == DWARF_DEBUG)
		    {
		      /* Mark the TYPE_DECL node we created just above as an
			 gratuitous one.  We need to do this so that dwarfout.c
			 will understand that it is not supposed to output a
			 TAG_typedef DIE  for it. */
		      DECL_IGNORED_P (d) = 1;
		    }
#endif /* DWARF_DEBUGGING_INFO */
		  set_identifier_type_value_with_scope (name, type, b);
		}
	      else
		d = TYPE_NAME (d);

	      TYPE_NAME (type) = d;

	      /* If it is anonymous, then we are called from pushdecl,
		 and we don't want to infinitely recurse.  */
	      if (! ANON_AGGRNAME_P (name))
		{
		  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);
#ifdef DWARF_DEBUGGING_INFO
	      if (write_symbols == DWARF_DEBUG)
		{
		  /* Mark the TYPE_DECL node we created just above as an
		     gratuitous one.  We need to do this so that dwarfout.c
		     will understand that it is not supposed to