[64bit] openldap compilation doesn't produce shared libraries
Thu Jun 13 08:52:00 GMT 2013
On Jun 13 10:37, Kai Tietz wrote:
> 2013/6/13 Corinna Vinschen wrote:
> > Too bad. This is a typical problem of projects which have been ported
> > to 64 bit, but only to SYSV ABI, not to MS ABI. The problem never shows
> > up in the SYSV ABI (Linux, Solaris, etc), because arguments < 64 bit are
> > zero extended when pushed on the stack. Unfortunately, in the MS ABI,
> > parameters < 64 bit are not zero extended so the higher bits can contain
> > any random value. Here, the uncasted 0 is int, so it's pushed on the
> > stack with the higher 32 bit set to any garbage this stack address
> > contains at the time.
> > Given our LP64-ness, I'm wondering if we couldn't tweak gcc to zero
> > extend arguments as well, even when otherwise using the MS ABI...
> > Corinna
> > --
> > Corinna Vinschen Please, send mails regarding Cygwin to
> > Cygwin Maintainer cygwin AT cygwin DOT com
> > Red Hat
> Hmm, well, we could do that, but it means of course in some cases a
> performance-penalty. For preventing some misunderstandings about
> MS-ABI I have to note that MS-ABI also extends argument also to
> natural-stack-boundary (means 8 byte on x64). Only difference here is
> that no sign-extending is used in general (in oppose to x86_64 ABI).
> So as quick feature this isn't implementable AFAICS due it has impact
> on behavior and performance.
That puzzles me quite a bit. If MS-ABI *does* extend arguments, and
only the signedness is a problem, then why does (int)0 pushes something
different on the stack than (long)0? Signedness can't be the reason
The only reason I can see for that is that the argument has not been
extended at all. Yes, it takes its 64 bit slot, but only 32 bits have
been written to the stack, apparently. Am I missing something?
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Maintainer cygwin AT cygwin DOT com
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