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Message-ID: <42DBE87D.9080600@martin-kittel.de>
Date: Mon, 18 Jul 2005 17:36:00 -0000
From: Martin Kittel <debian@martin-kittel.de>
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To:  gcc-help@gcc.gnu.org
Subject: Gcc-4.0 vtable layout on IA64
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Hi,

While trying to get the MaxDB sources compiled with gcc 4.0 on an IA64 
machine I stumbled over the following comment describing the vtable layout:

  *  gcc 3.1 on ia64 uses new c++ abi (without runtime type info):
  *
  *  pInterface -> 0  -----------        0  -----------------------
  *                  ! virt.Meth ! ------->| gp0        | Method 0 |
  *                   -----------          |------------|          |
  *                  !     :     !       8 | offset0    |          |
  *                                         ------------+----------|
  *                                     16 | gp1        | Method 1 |
  *                                         ------------|          |
  *                                     24 | offset1    |          |
  *                                         ------------+----------|
  *                                        |      :     |    :     |
  *                                               :
  *                                        |      :     |    :     |
  *                                         ------------+----------|
  *                             16*(n-1)+0 | gp n       | Method n |
  *                                         ------------|          |
  *                             16*(n-1)+8 | offset n   |          |
  *                                         ------------+----------

I was wondering if this is still correct with gcc 4.0 or whether there 
the formula should be 8*(n-1) to access method n (as that seems to 
correspond to what you have on i386)?


Thanks for any help,

Martin.