decl.c

gcc-2.95.3 Linux下最常用的C编译器

}

static void
resume_binding_level (b)
     struct binding_level *b;
{
  /* Resuming binding levels is meant only for namespaces,
     and those cannot nest into classes. */
  my_friendly_assert(!class_binding_level, 386);
  /* Also, resuming a non-directly nested namespace is a no-no.  */
  my_friendly_assert(b->level_chain == current_binding_level, 386);
  current_binding_level = b;
#if defined(DEBUG_CP_BINDING_LEVELS)
  b->binding_depth = binding_depth;
  indent ();
  fprintf (stderr, "resume %s level 0x%08x line %d\n",
	   (is_class_level) ? "class" : "block", b, lineno);
  is_class_level = 0;
  binding_depth++;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */
}

/* Create a new `struct binding_level'.  */

static
struct binding_level *
make_binding_level ()
{
  /* NOSTRICT */
  return (struct binding_level *) xmalloc (sizeof (struct binding_level));
}

/* Nonzero if we are currently in the global binding level.  */

int
global_bindings_p ()
{
  return current_binding_level == global_binding_level;
}

/* Return the innermost binding level that is not for a class scope.  */

static struct binding_level *
innermost_nonclass_level ()
{
  struct binding_level *b;

  b = current_binding_level;
  while (b->parm_flag == 2)
    b = b->level_chain;

  return b;
}

/* Nonzero if we are currently in a toplevel binding level.  This
   means either the global binding level or a namespace in a toplevel
   binding level.  Since there are no non-toplevel namespace levels,
   this really means any namespace or pseudo-global level.  We also
   include a class whose context is toplevel.  */

int
toplevel_bindings_p ()
{
  struct binding_level *b = innermost_nonclass_level ();

  return b->namespace_p || b->pseudo_global;
}

/* Nonzero if this is a namespace scope, or if we are defining a class
   which is itself at namespace scope, or whose enclosing class is
   such a class, etc.  */

int
namespace_bindings_p ()
{
  struct binding_level *b = innermost_nonclass_level ();

  return b->namespace_p;
}

void
keep_next_level ()
{
  keep_next_level_flag = 1;
}

/* Nonzero if the current level needs to have a BLOCK made.  */

int
kept_level_p ()
{
  return (current_binding_level->blocks != NULL_TREE
	  || current_binding_level->keep
	  || current_binding_level->names != NULL_TREE
	  || (current_binding_level->tags != NULL_TREE
	      && !current_binding_level->tag_transparent));
}

/* Identify this binding level as a level of parameters.  */

void
declare_parm_level ()
{
  current_binding_level->parm_flag = 1;
}

void
declare_pseudo_global_level ()
{
  current_binding_level->pseudo_global = 1;
}

static void
declare_namespace_level ()
{
  current_binding_level->namespace_p = 1;
}

int
pseudo_global_level_p ()
{
  struct binding_level *b = innermost_nonclass_level ();

  return b->pseudo_global;
}

void
set_class_shadows (shadows)
     tree shadows;
{
  class_binding_level->class_shadowed = shadows;
}

/* Enter a new binding level.
   If TAG_TRANSPARENT is nonzero, do so only for the name space of variables,
   not for that of tags.  */

void
pushlevel (tag_transparent)
     int tag_transparent;
{
  register struct binding_level *newlevel = NULL_BINDING_LEVEL;

  /* If this is the top level of a function,
     just make sure that NAMED_LABELS is 0.
     They should have been set to 0 at the end of the previous function.  */

  if (current_binding_level == global_binding_level)
    my_friendly_assert (named_labels == NULL_TREE, 134);

  /* Reuse or create a struct for this binding level.  */

#if defined(DEBUG_CP_BINDING_LEVELS)
  if (0)
#else /* !defined(DEBUG_CP_BINDING_LEVELS) */
  if (free_binding_level)
#endif /* !defined(DEBUG_CP_BINDING_LEVELS) */
    {
      newlevel = free_binding_level;
      free_binding_level = free_binding_level->level_chain;
    }
  else
    {
      newlevel = make_binding_level ();
    }

  push_binding_level (newlevel, tag_transparent, keep_next_level_flag);
  GNU_xref_start_scope ((HOST_WIDE_INT) newlevel);
  keep_next_level_flag = 0;
}

void
note_level_for_for ()
{
  current_binding_level->is_for_scope = 1;
}

void
pushlevel_temporary (tag_transparent)
     int tag_transparent;
{
  pushlevel (tag_transparent);
  current_binding_level->keep = 2;
  clear_last_expr ();

  /* Note we don't call push_momentary() here.  Otherwise, it would cause
     cleanups to be allocated on the momentary obstack, and they will be
     overwritten by the next statement.  */

  expand_start_bindings (0);
}

/* For a binding between a name and an entity at a block scope,
   this is the `struct binding_level' for the block.  */
#define BINDING_LEVEL(NODE) \
   (((struct tree_binding*)NODE)->scope.level)

/* These are currently unused, but permanent, CPLUS_BINDING nodes.
   They are kept here because they are allocated from the permanent
   obstack and cannot be easily freed.  */
static tree free_binding_nodes;

/* Make DECL the innermost binding for ID.  The LEVEL is the binding
   level at which this declaration is being bound.  */

static void
push_binding (id, decl, level)
     tree id;
     tree decl;
     struct binding_level* level;
{
  tree binding;

  if (!free_binding_nodes)
    {
      /* There are no free nodes, so we must build one here.  */
      push_obstacks_nochange ();
      end_temporary_allocation ();
      binding = make_node (CPLUS_BINDING);
      pop_obstacks ();
    }
  else
    {
      /* There are nodes on the free list.  Grab the first one.  */
      binding = free_binding_nodes;
      
      /* And update the free list.  */
      free_binding_nodes = TREE_CHAIN (free_binding_nodes);
    }

  /* Now, fill in the binding information.  */
  BINDING_VALUE (binding) = decl;
  BINDING_TYPE (binding) = NULL_TREE;
  BINDING_LEVEL (binding) = level;
  INHERITED_VALUE_BINDING_P (binding) = 0;
  LOCAL_BINDING_P (binding) = (level != class_binding_level);

  /* And put it on the front of the list of bindings for ID.  */
  TREE_CHAIN (binding) = IDENTIFIER_BINDING (id);
  IDENTIFIER_BINDING (id) = binding;
}

/* ID is already bound in the current scope.  But, DECL is an
   additional binding for ID in the same scope.  This is the `struct
   stat' hack whereby a non-typedef class-name or enum-name can be
   bound at the same level as some other kind of entity.  It's the
   responsibility of the caller to check that inserting this name is
   legal here.  Returns nonzero if the new binding was successful.  */
static int
add_binding (id, decl)
     tree id;
     tree decl;
{
  tree binding = IDENTIFIER_BINDING (id);
  int ok = 1;

  if (TREE_CODE (decl) == TYPE_DECL && DECL_ARTIFICIAL (decl))
    /* The new name is the type name.  */
    BINDING_TYPE (binding) = decl;
  else if (!BINDING_VALUE (binding))
    /* This situation arises when push_class_level_binding moves an
       inherited type-binding out of the way to make room for a new
       value binding.  */
    BINDING_VALUE (binding) = decl;
  else if (TREE_CODE (BINDING_VALUE (binding)) == TYPE_DECL
	   && DECL_ARTIFICIAL (BINDING_VALUE (binding)))
    {
      /* The old binding was a type name.  It was placed in
	 BINDING_VALUE because it was thought, at the point it was
	 declared, to be the only entity with such a name.  Move the
	 type name into the type slot; it is now hidden by the new
	 binding.  */
      BINDING_TYPE (binding) = BINDING_VALUE (binding);
      BINDING_VALUE (binding) = decl;
      INHERITED_VALUE_BINDING_P (binding) = 0;
    }
  else
    {
      cp_error ("declaration of `%#D'", decl);
      cp_error_at ("conflicts with previous declaration `%#D'",
		   BINDING_VALUE (binding));
      ok = 0;
    }

  return ok;
}

/* Bind DECL to ID in the current_binding_level.
   If PUSH_USING is set in FLAGS, we know that DECL doesn't really belong
   to this binding level, that it got here through a using-declaration.  */

void
push_local_binding (id, decl, flags)
     tree id;
     tree decl;
     int flags;
{
  struct binding_level *b;

  /* Skip over any local classes.  This makes sense if we call
     push_local_binding with a friend decl of a local class.  */
  b = current_binding_level;
  while (b->parm_flag == 2)
    b = b->level_chain;

  if (lookup_name_current_level (id))
    {
      /* Supplement the existing binding.  */
      if (!add_binding (id, decl))
	/* It didn't work.  Something else must be bound at this
	   level.  Do not add DECL to the list of things to pop
	   later.  */
	return;
    }
  else
    /* Create a new binding.  */
    push_binding (id, decl, b);

  if (TREE_CODE (decl) == OVERLOAD || (flags & PUSH_USING))
    /* We must put the OVERLOAD into a TREE_LIST since the
       TREE_CHAIN of an OVERLOAD is already used.  Similarly for
       decls that got here through a using-declaration.  */
    decl = build_tree_list (NULL_TREE, decl);

  /* And put DECL on the list of things declared by the current
     binding level.  */
  TREE_CHAIN (decl) = b->names;
  b->names = decl;
}

/* Bind DECL to ID in the class_binding_level.  Returns nonzero if the
   binding was successful.  */

int
push_class_binding (id, decl)
     tree id;
     tree decl;
{
  int result = 1;
  tree binding = IDENTIFIER_BINDING (id);
  tree context;

  /* Note that we declared this value so that we can issue an error if
     this an illegal redeclaration of a name already used for some
     other purpose.  */
  note_name_declared_in_class (id, decl);

  if (binding && BINDING_LEVEL (binding) == class_binding_level)
    /* Supplement the existing binding.  */
    result = add_binding (id, decl);
  else
    /* Create a new binding.  */
    push_binding (id, decl, class_binding_level);

  /* Update the IDENTIFIER_CLASS_VALUE for this ID to be the
     class-level declaration.  Note that we do not use DECL here
     because of the possibility of the `struct stat' hack; if DECL is
     a class-name or enum-name we might prefer a field-name, or some
     such.  */
  IDENTIFIER_CLASS_VALUE (id) = BINDING_VALUE (IDENTIFIER_BINDING (id));

  /* If this is a binding from a base class, mark it as such.  */
  binding = IDENTIFIER_BINDING (id);
  if (BINDING_VALUE (binding) == decl && TREE_CODE (decl) != TREE_LIST)
    {
      /* Any implicit typename must be from a base-class.  The
	 context for an implicit typename declaration is always
	 the derived class in which the lookup was done, so the checks
	 based on the context of DECL below will not trigger.  */
      if (TREE_CODE (decl) == TYPE_DECL 
	  && IMPLICIT_TYPENAME_P (TREE_TYPE (decl)))
	INHERITED_VALUE_BINDING_P (binding) = 1;
      else
	{
	  if (TREE_CODE (decl) == OVERLOAD)
	    context = DECL_REAL_CONTEXT (OVL_CURRENT (decl));
	  else
	    {
	      my_friendly_assert (TREE_CODE_CLASS (TREE_CODE (decl)) == 'd',
				  0);
	      context = DECL_REAL_CONTEXT (decl);
	    }

	  if (is_properly_derived_from (current_class_type, context))
	    INHERITED_VALUE_BINDING_P (binding) = 1;
	  else
	    INHERITED_VALUE_BINDING_P (binding) = 0;
	}
    }
  else if (BINDING_VALUE (binding) == decl)
    /* We only encounter a TREE_LIST when push_class_decls detects an
       ambiguity.  Such an ambiguity can be overridden by a definition
       in this class.  */
    INHERITED_VALUE_BINDING_P (binding) = 1;

  return result;
}

/* Remove the binding for DECL which should be the innermost binding
   for ID.  */

static void 
pop_binding (id, decl) 
     tree id;
     tree decl;
{
  tree binding;
    
  if (id == NULL_TREE)
    /* It's easiest to write the loops that call this function without
       checking whether or not the entities involved have names.  We
       get here for such an entity.  */
    return;

  /* Get the innermost binding for ID.  */
  binding = IDENTIFIER_BINDING (id);

  /* The name should be bound.  */
  my_friendly_assert (binding != NULL_TREE, 0);

  /* The DECL will be either the ordinary binding or the type
     binding for this identifier.  Remove that binding.  */
  if (BINDING_VALUE (binding) == decl)
    BINDING_VALUE (binding) = NULL_TREE;
  else if (BINDING_TYPE (binding) == decl)
    BINDING_TYPE (binding) = NULL_TREE;
  else
    my_friendly_abort (0);

  if (!BINDING_VALUE (binding) && !BINDING_TYPE (binding))
    {
      /* We're completely done with the innermost binding for this
	 identifier.  Unhook it from the list of bindings.  */
      IDENTIFIER_BINDING (id) = TREE_CHAIN (binding);

      /* And place it on the free list.  */
      TREE_CHAIN (binding) = free_binding_nodes;
      free_binding_nodes = binding;
    }