Re: lib/39465: threads stack is not aligned properly for gcc on i386

[David Holland <dholland-bugs%netbsd.org@localhost>]

The following reply was made to PR lib/39465; it has been noted by GNATS.

From: David Holland <dholland-bugs%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: lib/39465: threads stack is not aligned properly for gcc on i386
Date: Sat, 5 Nov 2011 12:59:15 +0000

 On Mon, Aug 29, 2011 at 09:20:05AM +0000, Anthony Mallet wrote:
  >  |  Separating out an extra "sp--" seems bogus
  >  
  >  I do not remember all the details, but IIRC separating sp-- was
  > the way to get it right (i.e. have the test program pass). I agree
  > that this seemed/seems bogus to me as well... Couldn't it be
  > because gcc assumes that the first variable on the stack is aligned
  > on 16 bytes, handling the ret address differently?
 
 It could be any number of similar things... but it's important to
 figure out what, or it'll probably break if something shifts around a
 little.
 
 Also, AIUI it's an ABI issue that can't fully be solved this way, and
 there's resistance to applying a patch like this - not correct
 resistance IMO but it's there nonetheless, so it's unlikely to be
 accepted for -5.
 
 Meanwhile, AFAIK now that HEAD has gcc 4.5 it's no longer necessary
 there.
 
 -- 
 David A. Holland
 dholland%netbsd.org@localhost