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To: Daniel Jacobowitz <drow@mvista.com>
Cc: gdb <gdb@sources.redhat.com>, Elena Zannoni <ezannoni@redhat.com>,
   Jim Blandy <jimb@redhat.com>
Subject: Re: DW_AT_containing_type
References: <m3brx3facd.fsf@dhcp-10-42-69-238.kealia.com>
	<20030612180714.GA19092@nevyn.them.org>
From: David Carlton <carlton@math.stanford.edu>
Date: Thu, 12 Jun 2003 18:16:00 -0000
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On Thu, 12 Jun 2003 14:07:14 -0400, Daniel Jacobowitz <drow@mvista.com> said:
> On Thu, Jun 12, 2003 at 10:56:50AM -0700, David Carlton wrote:

>> What's with GDB's and GCC's use of DW_AT_containing type?  As far as I
>> can tell, it's only supposed to be used within
>> DW_TAG_ptr_to_member_type, but GCC generates it and GDB uses it in
>> many other contexts.

> We are misusing it.  See the GCC source for a comment explaining
> this GNU extension.  We use it to indicate which base type contains
> the vtable pointer for the derived class; there are a number of
> other ways to do it, and at one point we should switch to another
> way.

Ah, thanks for the explanation.

David Carlton
carlton@math.stanford.edu