cp-search.c

早期freebsd实现

  basetype_chain = CLASSTYPE_BINFO_AS_LIST (type);
  TREE_VIA_PUBLIC (basetype_chain) = 1;

  search_stack = push_search_level (search_stack, &search_obstack);
  BINFO_VIA_PUBLIC (basetype_path) = 1;
  BINFO_INHERITANCE_CHAIN (basetype_path) = NULL_TREE;
  binfo = basetype_path;

  while (1)
    {
      tree binfos = BINFO_BASETYPES (binfo);
      int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

      /* Process and/or queue base types.  */
      for (i = 0; i < n_baselinks; i++)
	{
	  tree base_binfo = TREE_VEC_ELT (binfos, i);
	  if (BINFO_FIELDS_MARKED (base_binfo) == 0)
	    {
	      tree btypes;

	      SET_BINFO_FIELDS_MARKED (base_binfo);
	      btypes = my_tree_cons (NULL_TREE, base_binfo, basetype_chain);
	      TREE_VIA_PUBLIC (btypes) = TREE_VIA_PUBLIC (base_binfo);
	      TREE_VIA_PROTECTED (btypes) = TREE_VIA_PROTECTED (base_binfo);
	      TREE_VIA_VIRTUAL (btypes) = TREE_VIA_VIRTUAL (base_binfo);
	      obstack_ptr_grow (&search_obstack, btypes);
	      tail += 1;
	      if (tail >= search_stack->limit)
		my_friendly_abort (98);
	    }
	}

      /* Process head of queue, if one exists.  */
      if (head >= tail)
	break;

      basetype_chain = search_stack->first[head++];
      basetype_path = TREE_VALUE (basetype_chain);
      if (TREE_CHAIN (basetype_chain))
	BINFO_INHERITANCE_CHAIN (basetype_path) = TREE_VALUE (TREE_CHAIN (basetype_chain));
      else
	BINFO_INHERITANCE_CHAIN (basetype_path) = NULL_TREE;

      binfo = basetype_path;
      type = BINFO_TYPE (binfo);

      /* See if we can find NAME in TYPE.  If RVAL is nonzero,
	 and we do find NAME in TYPE, verify that such a second
	 sighting is in fact legal.  */

      if (rval)
	{
	  tree context = DECL_FIELD_CONTEXT (rval);
	  /* Just another way of finding the same member.  */
	  if (TYPE_BINFO (context) == binfo)
	    {
	      enum visibility_type new_v
		= compute_visibility (basetype_path, rval);
	      if (this_v != new_v)
		errstr = "conflicting visibilities to member `%s'";
	    }
	  /* Same baseclass, maybe different places in the lattice.  */
	  else if (context == type)
	    {
	      errstr = "member `%s' belongs to distinct base classes `%s'";
	      protect = 2;
	    }
	  else
	    {
	      tree nval = lookup_field_1 (type, name);

	      if (nval && TREE_CODE (nval) != TYPE_DECL && want_type)
		nval = NULL_TREE;


	      if (nval
		  && binfo != get_binfo (type, DECL_FIELD_CONTEXT (rval), 0))
		{
		  /* We found it in other than a baseclass of RVAL's.  */
		  errstr = "request for member `%s' is ambiguous";
		  protect = 2;
		}
	    }
	  if (errstr && entry)
	    {
	      tree error_string = my_build_string (errstr);
	      TREE_TYPE (entry) = error_string;
	    }
	  if (errstr && protect)
	    break;
	}
      else
	{
	  rval = lookup_field_1 (type, name);

	  if (rval && TREE_CODE (rval) != TYPE_DECL && want_type)
	    rval = NULL_TREE;

	  if (rval)
	    {
	      if (entry || protect)
		this_v = compute_visibility (basetype_path, rval);
	      if (entry)
		TREE_VALUE (entry) = rval;

	      /* These may look ambiguous, but they really are not.  */
	      if (vbase_name_p)
		break;
	    }
	}
    }
  {
    tree *tp = search_stack->first;
    tree *search_tail = tp + tail;

    /* If this FIELD_DECL defines its own visibility, deal with that.  */
    if (rval && errstr == 0
	&& ((protect&1) || entry)
	&& DECL_LANG_SPECIFIC (rval)
	&& DECL_VISIBILITY (rval))
      {
	while (tp < search_tail)
	  {
	    /* If is possible for one of the derived types on the
	       path to have defined special visibility for this
	       field.  Look for such declarations and report an
	       error if a conflict is found.  */
	    enum visibility_type new_v;

	    if (this_v != visibility_default)
	      new_v = compute_visibility (TREE_VALUE (*tp), rval);
	    if (this_v != visibility_default && new_v != this_v)
	      {
		errstr = "conflicting visibilities to member `%s'";
		this_v = visibility_default;
	      }
	    own_visibility = new_v;
	    CLEAR_BINFO_FIELDS_MARKED (TREE_VALUE (*tp));
	    tp += 1;
	  }
      }
    else
      {
	while (tp < search_tail)
	  {
	    CLEAR_BINFO_FIELDS_MARKED (TREE_VALUE (*tp));
	    tp += 1;
	  }
      }
  }
  search_stack = pop_search_level (search_stack);

  if (errstr == 0)
    {
      if (own_visibility == visibility_private)
	errstr = "member `%s' declared private";
      else if (own_visibility == visibility_protected)
	errstr = "member `%s' declared protected";
      else if (this_v == visibility_private)
	errstr = TREE_PRIVATE (rval)
	  ? "member `%s' is private"
	    : "member `%s' is from private base class";
      else if (this_v == visibility_protected)
	errstr = TREE_PROTECTED (rval)
	  ? "member `%s' is protected"
	    : "member `%s' is from protected base class";
    }

  if (entry)
    {
      if (errstr)
	{
	  tree error_string = my_build_string (errstr);
	  /* Save error message with entry.  */
	  TREE_TYPE (entry) = error_string;
	}
      else
	{
	  /* Mark entry as having no error string.  */
	  TREE_TYPE (entry) = NULL_TREE;
	}
    }

  if (errstr && protect)
    {
      error (errstr, IDENTIFIER_POINTER (name), TYPE_NAME_STRING (type));
      rval = error_mark_node;
    }
  return rval;
}

/* Try to find NAME inside a nested class.  */
tree
lookup_nested_field (name)
     tree name;
{
  register tree t;

  tree id = NULL_TREE;
  if (TREE_CHAIN (current_class_type))
    {
      /* Climb our way up the nested ladder, seeing if we're trying to
	 modify a field in an enclosing class.  If so, we should only
	 be able to modify if it's static.  */
      for (t = TREE_CHAIN (current_class_type);
	   t && DECL_CONTEXT (t);
	   t = TREE_CHAIN (DECL_CONTEXT (t)))
	{
	  if (TREE_CODE (DECL_CONTEXT (t)) != RECORD_TYPE)
	    break;

	  /* N.B.: lookup_field will do the visibility checking for us */
	  id = lookup_field (DECL_CONTEXT (t), name, 1, 0);
	  if (id == error_mark_node)
	    continue;
	  if (id != NULL_TREE)
	    {
	      if (TREE_CODE (id) == FIELD_DECL
		  && ! TREE_STATIC (id)
		  && TREE_TYPE (id) != error_mark_node)
		{
		  error ("assignment to non-static member `%s' of enclosing class `%s'",
			 lang_printable_name (id),
			 IDENTIFIER_POINTER (TYPE_IDENTIFIER
					     (DECL_CONTEXT (t))));
		  /* Mark this for do_identifier().  It would otherwise
		     claim that the variable was undeclared.  */
		  TREE_TYPE (id) = error_mark_node;
		}
	      break;
	    }
	}
    }

  return id;
}

/* TYPE is a class type. Return the index of the fields within
   the method vector with name NAME, or -1 is no such field exists.  */
static int
lookup_fnfields_1 (type, name)
     tree type, name;
{
  register tree method_vec = CLASSTYPE_METHOD_VEC (type);

  if (method_vec != 0)
    {
      register tree *methods = &TREE_VEC_ELT (method_vec, 0);
      register tree *end = TREE_VEC_END (method_vec);

#ifdef GATHER_STATISTICS
      n_calls_lookup_fnfields_1++;
#endif
      if (*methods && name == constructor_name (type))
	return 0;

      while (++methods != end)
	{
#ifdef GATHER_STATISTICS
	  n_outer_fields_searched++;
#endif
	  if (DECL_NAME (*methods) == name)
	    break;
	}
      if (methods != end)
	return methods - &TREE_VEC_ELT (method_vec, 0);
    }

  return -1;
}

/* Starting from BASETYPE, return a TREE_BASELINK-like object
   which gives the following information (in a list):

   TREE_TYPE: list of basetypes needed to get to...
   TREE_VALUE: list of all functions in of given type
   which have name NAME.

   No visibility information is computed by this function,
   other then to adorn the list of basetypes with
   TREE_VIA_PUBLIC.

   If FIND_AMBIGUOUS is non-zero, then if we find two ways to get
   to the same member function, both those ways are found,
   and the caller must know what to do about this.  */
tree
lookup_fnfields (basetype_path, name, find_ambiguous)
     tree basetype_path, name;
     int find_ambiguous;
{
  int head = 0, tail = 0;
  tree type, rval, rvals = NULL_TREE;
  tree entry, binfo, basetype_chain;

  /* For now, don't try this.  */
  int protect = find_ambiguous;

  /* Things for memoization.  */
  char *errstr = 0;

  /* Set this to nonzero if we don't know how to compute
     accurate error messages for visibility.  */
  int index = MEMOIZED_HASH_FN (name);

  binfo = basetype_path;
  type = BINFO_TYPE (basetype_path);

  if (CLASSTYPE_MTABLE_ENTRY (type))
    {
      tree tem = MEMOIZED_FNFIELDS (CLASSTYPE_MTABLE_ENTRY (type), index);

      while (tem && TREE_PURPOSE (tem) != name)
	{
	  memoized_fields_searched[1]++;
	  tem = TREE_CHAIN (tem);
	}
      if (tem)
	{
	  if (protect && TREE_TYPE (tem))
	    {
	      error (TREE_STRING_POINTER (TREE_TYPE (tem)),
		     IDENTIFIER_POINTER (name),
		     TYPE_NAME_STRING (DECL_CLASS_CONTEXT (TREE_VALUE (TREE_VALUE (tem)))));
	      return error_mark_node;
	    }
	  if (TREE_VALUE (tem) == NULL_TREE)
	    {
	      memoized_fast_rejects[1] += 1;
	      return NULL_TREE;
	    }
	  else
	    {
	      /* Want to return this, but we must make sure
		 that visibility information is consistent.  */
	      tree baselink = TREE_VALUE (tem);
	      tree memoized_basetypes = TREE_PURPOSE (baselink);
	      tree these_basetypes = basetype_path;
	      while (memoized_basetypes && these_basetypes)
		{
		  memoized_fields_searched[1]++;
		  if (TREE_VALUE (memoized_basetypes) != these_basetypes)
		    break;
		  memoized_basetypes = TREE_CHAIN (memoized_basetypes);
		  these_basetypes = BINFO_INHERITANCE_CHAIN (these_basetypes);
		}
	      /* The following statement is true only when both are NULL.  */
	      if (memoized_basetypes == these_basetypes)
		{
		  memoized_fast_finds[1] += 1;
		  return TREE_VALUE (tem);
		}
	      /* else, we must re-find this field by hand.  */
	      baselink = tree_cons (basetype_path, TREE_VALUE (baselink), TREE_CHAIN (baselink));
	      return baselink;
	    }
	}
    }

#ifdef GATHER_STATISTICS
  n_calls_lookup_fnfields++;
#endif
  if (protect && flag_memoize_lookups && ! global_bindings_p ())
    entry = make_memoized_table_entry (type, name, 1);
  else
    entry = 0;

  index = lookup_fnfields_1 (type, name);

  if (index >= 0)
    {
      rval = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), index);
      rvals = my_tree_cons (basetype_path, rval, NULL_TREE);
      if (BINFO_BASETYPES (binfo) && CLASSTYPE_BASELINK_VEC (type))
	TREE_TYPE (rvals) = TREE_VEC_ELT (CLASSTYPE_BASELINK_VEC (type), index);

      if (entry)
	{
	  TREE_VALUE (entry) = rvals;
	  TREE_TYPE (entry) = NULL_TREE;
	}

      if (errstr && protect)
	{
	  error (errstr, IDENTIFIER_POINTER (name), TYPE_NAME_STRING (type));
	  return error_mark_node;
	}
      return rvals;
    }
  rval = NULL_TREE;

  basetype_chain = CLASSTYPE_BINFO_AS_LIST (type);
  TREE_VIA_PUBLIC (basetype_chain) = 1;

  search_stack = push_search_level (search_stack, &search_obstack);
  BINFO_VIA_PUBLIC (basetype_path) = 1;
  BINFO_INHERITANCE_CHAIN (basetype_path) = NULL_TREE;
  binfo = basetype_path;

  while (1)
    {
      tree binfos = BINFO_BASETYPES (binfo);
      int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

      /* Process and/or queue base types.  */
      for (i = 0; i < n_baselinks; i++)
	{
	  tree base_binfo = TREE_VEC_ELT (binfos, i);
	  if (BINFO_FIELDS_MARKED (base_binfo) == 0)
	    {
	      tree btypes;

	      SET_BINFO_FIELDS_MARKED (base_binfo);
	      btypes = my_tree_cons (NULL_TREE, base_binfo, basetype_chain);
	      TREE_VIA_PUBLIC (btypes) = TREE_VIA_PUBLIC (base_binfo);
	      TREE_VIA_PROTECTED (btypes) = TREE_VIA_PROTECTED (base_binfo);
	      TREE_VIA_VIRTUAL (btypes) = TREE_VIA_VIRTUAL (base_binfo);
	      obstack_ptr_grow (&search_obstack, btypes);
	      tail += 1;
	      if (tail >= search_stack->limit)
		my_friendly_abort (99);
	    }
	}

      /* Process head of queue, if one exists.  */
      if (head >= tail)
	break;

      basetype_chain = search_stack->first[head++];
      basetype_path = TREE_VALUE (basetype_chain);
      if (TREE_CHAIN (basetype_chain))
	BINFO_INHERITANCE_CHAIN (basetype_path) = TREE_VALUE (TREE_CHAIN (basetype_chain));
      else
	BINFO_INHERITANCE_CHAIN (basetype_path) = NULL_TREE;

      binfo = basetype_path;
      type = BINFO_TYPE (binfo);

      /* See if we can find NAME in TYPE.  If RVAL is nonzero,
	 and we do find NAME in TYPE, verify that such a second
	 sighting is in fact legal.  */

      if (rval)
	{
	  tree context = DECL_CLASS_CONTEXT (rval);
	  /* Just another way of finding the same member.  */
	  if (TYPE_BINFO (context) == binfo)
	    ;
	  /* Same baseclass, maybe different places in the lattice.  */
	  else if (context == type)
	    {
	      if (TREE_VIA_VIRTUAL (TREE_PURPOSE (rvals)))
		if (TREE_VIA_VIRTUAL (binfo))
		  ;
		else
		  errstr = "member `%s' belongs to virtual and non-virtual baseclasses `%s'";