search.c

GCC编译器源代码

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

      return rvals;
    }
  rval = NULL_TREE;

  if (name == ctor_identifier || name == dtor_identifier)
    {
      /* Don't allow lookups of constructors and destructors to go
 	 deeper than the first place we look.  */
      if (entry)
 	TREE_TYPE (entry) = TREE_VALUE (entry) = NULL_TREE;

      return NULL_TREE;
    }

  if (basetype_path == TYPE_BINFO (type))
    {
      basetype_chain = CLASSTYPE_BINFO_AS_LIST (type);
      TREE_VIA_PUBLIC (basetype_chain) = 1;
      BINFO_VIA_PUBLIC (basetype_path) = 1;
      BINFO_INHERITANCE_CHAIN (basetype_path) = NULL_TREE;
    }
  else
    {
      basetype_chain = build_expr_list (NULL_TREE, basetype_path);
      TREE_VIA_PUBLIC (basetype_chain) = TREE_VIA_PUBLIC (basetype_path);
      TREE_VIA_PROTECTED (basetype_chain) = TREE_VIA_PROTECTED (basetype_path);
      TREE_VIA_VIRTUAL (basetype_chain) = TREE_VIA_VIRTUAL (basetype_path);
    }

  /* The ambiguity check relies upon breadth first searching.  */

  search_stack = push_search_level (search_stack, &search_obstack);
  binfo = basetype_path;
  binfo_h = binfo;

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

      /* 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);
	      if (TREE_VIA_VIRTUAL (base_binfo))
		btypes = my_tree_cons (NULL_TREE,
				    TYPE_BINFO (BINFO_TYPE (TREE_VEC_ELT (BINFO_BASETYPES (binfo_h), i))),
				    btypes);
	      else
		btypes = my_tree_cons (NULL_TREE,
				    TREE_VEC_ELT (BINFO_BASETYPES (binfo_h), i),
				    btypes);
	      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++];
      binfo_h = TREE_VALUE (basetype_chain);
      basetype_chain = TREE_CHAIN (basetype_chain);
      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 valid.  */

      idx = lookup_fnfields_here (type, name);

      if (idx >= 0 || (lookup_field_1 (type, name)!=NULL_TREE && !find_all))
	{
	  if (rval_binfo && !find_all && hides (rval_binfo_h, binfo_h))
	    {
	      /* This is ok, the member found is in rval_binfo, not
		 here (binfo).  */
	    }
	  else if (rval_binfo==NULL_TREE || find_all || hides (binfo_h, rval_binfo_h))
	    {
	      /* This is ok, the member found is here (binfo), not in
		 rval_binfo.  */
	      if (idx >= 0)
		{
		  rval = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), idx);
		  /* Note, rvals can only be previously set if find_all is
		     true.  */
		  rvals = my_tree_cons (basetype_path, rval, rvals);
		  if (TYPE_BINFO_BASETYPES (type)
		      && CLASSTYPE_BASELINK_VEC (type))
		    TREE_TYPE (rvals) = TREE_VEC_ELT (CLASSTYPE_BASELINK_VEC (type), idx);
		}
	      else
		{
		  /* Undo finding it before, as something else hides it.  */
		  rval = NULL_TREE;
		  rvals = NULL_TREE;
		}
	      rval_binfo = binfo;
	      rval_binfo_h = binfo_h;
	    }
	  else
	    {
	      /* This is ambiguous.  */
	      errstr = "request for method `%D' is ambiguous";
	      rvals = error_mark_node;
	      break;
	    }
	}
    }
  {
    tree *tp = search_stack->first;
    tree *search_tail = tp + tail;

    while (tp < search_tail)
      {
	CLEAR_BINFO_FIELDS_MARKED (TREE_VALUE (TREE_CHAIN (*tp)));
	tp += 1;
      }
  }
  search_stack = pop_search_level (search_stack);

  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;
	  TREE_VALUE (entry) = rvals;
	}
    }

  if (errstr && protect)
    {
      cp_error (errstr, name);
      rvals = error_mark_node;
    }

  return rvals;
}

/* BREADTH-FIRST SEARCH ROUTINES.  */

/* Search a multiple inheritance hierarchy by breadth-first search.

   BINFO is an aggregate type, possibly in a multiple-inheritance hierarchy.
   TESTFN is a function, which, if true, means that our condition has been met,
   and its return value should be returned.
   QFN, if non-NULL, is a predicate dictating whether the type should
   even be queued.  */

static HOST_WIDE_INT
breadth_first_search (binfo, testfn, qfn)
     tree binfo;
     int (*testfn) PROTO((tree, int));
     int (*qfn) PROTO((tree, int));
{
  int head = 0, tail = 0;
  int rval = 0;

  search_stack = push_search_level (search_stack, &search_obstack);

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

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

	  if (BINFO_MARKED (base_binfo) == 0
	      && (qfn == 0 || (*qfn) (binfo, i)))
	    {
	      SET_BINFO_MARKED (base_binfo);
	      obstack_ptr_grow (&search_obstack, binfo);
	      obstack_ptr_grow (&search_obstack, (HOST_WIDE_INT) i);
	      tail += 2;
	      if (tail >= search_stack->limit)
		my_friendly_abort (100);
	    }
	}
      /* Process head of queue, if one exists.  */
      if (head >= tail)
	{
	  rval = 0;
	  break;
	}

      binfo = search_stack->first[head++];
      i = (HOST_WIDE_INT) search_stack->first[head++];
      if (rval = (*testfn) (binfo, i))
	break;
      binfo = BINFO_BASETYPE (binfo, i);
    }
  {
    tree *tp = search_stack->first;
    tree *search_tail = tp + tail;
    while (tp < search_tail)
      {
	tree binfo = *tp++;
	int i = (HOST_WIDE_INT)(*tp++);
	CLEAR_BINFO_MARKED (BINFO_BASETYPE (binfo, i));
      }
  }

  search_stack = pop_search_level (search_stack);
  return rval;
}

/* Functions to use in breadth first searches.  */
typedef int (*pfi) PROTO((tree, int));

static tree declarator;

static tree
get_virtuals_named_this (binfo)
     tree binfo;
{
  tree fields;

  fields = lookup_fnfields (binfo, declarator, -1);
  /* fields cannot be error_mark_node */

  if (fields == 0)
    return 0;

  /* Get to the function decls, and return the first virtual function
     with this name, if there is one.  */
  while (fields)
    {
      tree fndecl;

      for (fndecl = TREE_VALUE (fields); fndecl; fndecl = DECL_CHAIN (fndecl))
	if (DECL_VINDEX (fndecl))
	  return fields;
      fields = next_baselink (fields);
    }
  return NULL_TREE;
}

static tree
get_virtual_destructor (binfo, i)
     tree binfo;
     int i;
{
  tree type = BINFO_TYPE (binfo);
  if (i >= 0)
    type = BINFO_TYPE (TREE_VEC_ELT (BINFO_BASETYPES (binfo), i));
  if (TYPE_HAS_DESTRUCTOR (type)
      && DECL_VINDEX (TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), 1)))
    return TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (type), 1);
  return 0;
}

static int
tree_has_any_destructor_p (binfo, i)
     tree binfo;
     int i;
{
  tree type = BINFO_TYPE (binfo);
  if (i >= 0)
    type = BINFO_TYPE (TREE_VEC_ELT (BINFO_BASETYPES (binfo), i));
  return TYPE_NEEDS_DESTRUCTOR (type);
}

/* Given a class type TYPE, and a function decl FNDECL, look for a
   virtual function in TYPE's hierarchy which FNDECL could match as a
   virtual function.  It doesn't matter which one we find.

   DTORP is nonzero if we are looking for a destructor.  Destructors
   need special treatment because they do not match by name.  */

tree
get_matching_virtual (binfo, fndecl, dtorp)
     tree binfo, fndecl;
     int dtorp;
{
  tree tmp = NULL_TREE;

  /* Breadth first search routines start searching basetypes
     of TYPE, so we must perform first ply of search here.  */
  if (dtorp)
    {
      if (tree_has_any_destructor_p (binfo, -1))
	tmp = get_virtual_destructor (binfo, -1);

      if (tmp)
	return tmp;

      tmp = (tree) breadth_first_search (binfo,
					 (pfi) get_virtual_destructor,
					 tree_has_any_destructor_p);
      return tmp;
    }
  else
    {
      tree drettype, dtypes, btypes, instptr_type;
      tree basetype = DECL_CLASS_CONTEXT (fndecl);
      tree baselink, best = NULL_TREE;
      tree name = DECL_ASSEMBLER_NAME (fndecl);

      declarator = DECL_NAME (fndecl);
      if (IDENTIFIER_VIRTUAL_P (declarator) == 0)
	return NULL_TREE;

      baselink = get_virtuals_named_this (binfo);
      if (baselink == NULL_TREE)
	return NULL_TREE;

      drettype = TREE_TYPE (TREE_TYPE (fndecl));
      dtypes = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
      if (DECL_STATIC_FUNCTION_P (fndecl))
	instptr_type = NULL_TREE;
      else
	instptr_type = TREE_TYPE (TREE_VALUE (dtypes));

      for (; baselink; baselink = next_baselink (baselink))
	{
	  for (tmp = TREE_VALUE (baselink); tmp; tmp = DECL_CHAIN (tmp))
	    {
	      if (! DECL_VINDEX (tmp))
		continue;

	      btypes = TYPE_ARG_TYPES (TREE_TYPE (tmp));
	      if (instptr_type == NULL_TREE)
		{
		  if (compparms (TREE_CHAIN (btypes), dtypes, 3))
		    /* Caller knows to give error in this case.  */
		    return tmp;
		  return NULL_TREE;
		}

	      if ((TYPE_READONLY (TREE_TYPE (TREE_VALUE (btypes)))
		   == TYPE_READONLY (instptr_type))
		  && compparms (TREE_CHAIN (btypes), TREE_CHAIN (dtypes), 3))
		{
		  tree brettype = TREE_TYPE (TREE_TYPE (tmp));
		  if (comptypes (brettype, drettype, 1))
		    /* OK */;
		  else if
		    (TREE_CODE (brettype) == TREE_CODE (drettype)
		     && (TREE_CODE (brettype) == POINTER_TYPE
			 || TREE_CODE (brettype) == REFERENCE_TYPE)
		     && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (brettype)),
				   TYPE_MAIN_VARIANT (TREE_TYPE (drettype)),
				   0))
		      /* covariant return type */
		    {
		      tree b = TREE_TYPE (brettype), d = TREE_TYPE (drettype);
		      if (TYPE_MAIN_VARIANT (b) != TYPE_MAIN_VARIANT (d))
			{
			  tree binfo = get_binfo (b, d, 1);
			  if (binfo != error_mark_node
			      && (! BINFO_OFFSET_ZEROP (binfo)
				  || TREE_VIA_VIRTUAL (binfo)))
			    sorry ("adjusting pointers for covariant returns");
			}
		      if (TYPE_READONLY (d) > TYPE_READONLY (b))
			{
			  cp_error_at ("return type of `%#D' adds const", fndecl);
			  cp_error_at ("  overriding definition as `%#D'",
				       tmp);
			}
		      else if (TYPE_VOLATILE (d) > TYPE_VOLATILE (b))
			{
			  cp_error_at ("return type of `%#D' adds volatile",
				    fndecl);
			  cp_error_at ("  overriding definition as `%#D'",
				       tmp);
			}
		    }
		  else if (IS_AGGR_TYPE_2 (brettype, drettype)
			   && comptypes (brettype, drettype, 0))
		    {
		      error ("invalid covariant return type (must use pointer or reference)");
		      cp_error_at ("  overriding `%#D'", tmp);
		      cp_error_at ("  with `%#D'", fndecl);
		    }
		  else if (IDENTIFIER_ERROR_LOCUS (name) == NULL_TREE)
		    {
		      cp_error_at ("conflicting return type specified for virtual function `%#D'", fndecl);
		      cp_error_at ("  overriding definition as `%#D'", tmp);
		      SET_IDENTIFIER_ERROR_LOCUS (name, basetype);
		    }
		  break;
		}
	    }
	  if (tmp)
	    {
	      best = tmp;
	      break;
	    }
	}

      return best;
    }
}

/* Return the list of virtual functions which are abstract in type
   TYPE that come from non virtual base classes.  See
   expand_direct_vtbls_init for the style of search we do.  */

static tree
get_abstract_virtuals_1 (binfo, do_self, abstract_virtuals)
     tree binfo;
     int do_self;
     tree abstract_virtuals;
{
  tree binfos = BINFO_BASETYPES (binfo);
  int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

  for (i = 0; i < n_baselinks; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      int is_not_base_vtable
	= i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo));
      if (! TREE_VIA_VIRTU