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Date:      Sun, 7 Aug 2011 13:52:56 +0200
From:      Marius Strobl <marius@alchemy.franken.de>
To:        Marcel Moolenaar <marcel@xcllnt.net>
Cc:        src-committers@FreeBSD.org, Ruslan Mahmatkhanov <cvs-src@yandex.ru>, Garrett Cooper <yanegomi@gmail.com>, svn-src-all@FreeBSD.org, Andriy Gapon <avg@FreeBSD.org>, svn-src-head@FreeBSD.org
Subject:   Re: svn commit: r224683 - head/lib/libthread_db
Message-ID:  <20110807115256.GG48988@alchemy.franken.de>
In-Reply-To: <96C6C36B-E521-4438-9AEF-59D9A922D3B4@xcllnt.net>
References:  <201108061748.p76HmUbM061259@svn.freebsd.org> <4E3DA560.6020100@yandex.ru> <CAGH67wSFRXLRBVcoR8RME111pE7UaZ+y-k8qmTtCkOy+MC3Dhw@mail.gmail.com> <4E3DBAF8.5040102@FreeBSD.org> <20110806232415.GE48988@alchemy.franken.de> <96C6C36B-E521-4438-9AEF-59D9A922D3B4@xcllnt.net>

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On Sat, Aug 06, 2011 at 07:35:49PM -0700, Marcel Moolenaar wrote:
> 
> On Aug 6, 2011, at 4:24 PM, Marius Strobl wrote:
> 
> > On Sun, Aug 07, 2011 at 01:06:48AM +0300, Andriy Gapon wrote:
> >> on 07/08/2011 00:41 Garrett Cooper said the following:
> >>> It's not just i386. It's other architectures like arm, mips, and pc98
> >>> according to the tinderbox reports (this list is potentially
> >>> incomplete).
> >> 
> >> Yeah, confusingly enough thr_pread_long() is declared to take uint64_t* as its
> >> third argument, so this commit breaks all platforms where uint64_t is not
> >> derived from (unsigned) long.
> >> Just in case, thr_pread_int() takes uint32_t* as well.
> >> 
> > 
> > Yes, the type of val is wrong. I'm currently running a fix through a
> > universe build
> 
> Ah, euh, ok, I forgot about this particular quirk:
> 
> uint64_t is deliberate, because it's the width of long on 64-bit
> architectures and thread_db is to be used as a support library
> for a cross-tool (i.e. a 32-bit debugger for a 64-bit target).
> 
> That's why thr_pread_long() takes a pointer to uint64_t and
> thr_pread_int() takes a pointer to uint32_t...
> 
> Sorry for missing this in the review.

Okay, but then I don't know how to properly fix this given that
thr_p{read,write}_long() still seem to do the wrong thing as they
supply sizeof(long) rather than the size of a long on the target
to thr_p{read,write}() as the size of the value in the target
address space. If I change the callers of thr_pread_long() to
supply a uint64_t this will compile but it still does the wrong
thing in the cross-debugging case and I can't even think of how
to fix that without additional information about the target, i.e.
just using sizeof(uint64_t) obviously also is the wrong thing.
Both thr_p{read,write}_ptr() are similarly confusing as they take
a psaddr_t which is defined as uint64_t but use sizeof(void *)
which again is specific to the host rather tan the target.
Do you have a suggestion how to fix these?

Marius




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