g++ exception_support.h has original_value, but not the compiler

[Brendan Kehoe <brendan at zen dot org>]

Unless it's been known to not matter (and thus would call for a suitable
comment in the header), the type struct cp_eh_info in
libstdc++-v3/libsupc++/exception_support.h has an `original_value' pointer as
its final field:

struct cp_eh_info
{
  __eh_info eh_info;
  void *value;
  void *type;
  cleanup_fn cleanup;
  bool caught;
  cp_eh_info *next;
  long handlers;
  void *original_value;
};


However, the cp_eh_info constructed inside gcc/cp/except.c does not include
that one, finishing at the "handlers" member:

      t = make_aggr_type (RECORD_TYPE);
      fields[0] = build_decl (FIELD_DECL, 
                              get_identifier ("eh_info"), t1);
      fields[1] = build_decl (FIELD_DECL, get_identifier ("value"),
                              ptr_type_node);
      fields[2] = build_decl (FIELD_DECL, get_identifier ("type"),
                              ptr_type_node);
      fields[3] = build_decl
        (FIELD_DECL, get_identifier ("cleanup"),
         build_pointer_type (build_function_type
                             (ptr_type_node, tree_cons
                              (NULL_TREE, ptr_type_node, void_list_node))));
      fields[4] = build_decl (FIELD_DECL, get_identifier ("caught"),
                              boolean_type_node);
      fields[5] = build_decl (FIELD_DECL, get_identifier ("next"),
                              build_pointer_type (t));
      fields[6] = build_decl
        (FIELD_DECL, get_identifier ("handlers"), long_integer_type_node);
      /* N.B.: The fourth field LEN is expected to be
         the number of fields - 1, not the total number of fields.  */
      finish_builtin_type (t, "cp_eh_info", fields, 6, ptr_type_node);

Deliberate, or accidental?

Hope this helps,
B