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Re: C++ ABI: Reuse of tail padding
- From: Mark Mitchell <mark at codesourcery dot com>
- To: Nathan Sidwell <nathan at codesourcery dot com>
- Cc: "cxx-abi-dev at codesourcery dot com" <cxx-abi-dev at codesourcery dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>, "jason at redhat dot com" <jason at redhat dot com>
- Date: Wed, 14 Aug 2002 15:20:08 -0700
- Subject: Re: C++ ABI: Reuse of tail padding
--On Wednesday, August 14, 2002 10:15:07 PM +0100 Nathan Sidwell
Mark Mitchell wrote:
We have a problem here.
Intel's compiler does not pack things into the tail padding.
Neither, I expect, does HP's.
I would like to get hard data from more than the two compilers
There aren't many more to find. HP, Intel, and GCC are the compilers
that have implemented the ABI to date.
Others are in the process, which is part of why this is important.
I think I would prefer to change G++, and drop this idea from the spec,
even though it is an optimization.
Although using tail padding is neat, how many bytes would it
save in real programs? You only get it with structs of the form
or (on some non-i86 machines)
Well, that sounds like two votes for changing G++ (and clarifying the
spec to drop any hint of using tail padding).
Mark Mitchell firstname.lastname@example.org
CodeSourcery, LLC http://www.codesourcery.com