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From: Rob Newberry <robnewberry@grouplogic.com>
To: gcc-help@gcc.gnu.org
Subject: GCC 2.9.5, Solaris 2.8, SPARC - alignment issue - PLEASE HELP!
Date: Tue, 24 Jul 2001 14:24:00 -0000	[thread overview]
Message-ID: <Pine.LNX.4.10.10107241712190.17275-100000@host3.grouplogic.com> (raw)

Hi,

I have some legacy code, and I really, really, really need to not modify
it.  This code has alignment issues, but I would expect the compiler (or
the OS maybe) to handle this for me.

Here's some example of the code that causes problems:

        char    key[256];
        long    value = 1;

	// this causes a SIGSEGV on SPARC
        *((long*)&key[2]) = value;

I know this is cruddy, but I would _EXPECT_ the compiler to essentially
catch this and (more-or-less) rewrite it as something similar to:

	memcpy( &key[2], &value, sizeof(long));

I have tried compiling with STRICT_ALIGNMENT=1 and
SLOW_UNALIGNED_ACCESS=1, but neither is helping.  It always seg-faults.

Is there a solution to my problem on Sun OS 5.8 with GCC?

I am amenable to mucking with the Makefile or changing some kind of OS
configuration.  The thing that I can't do is modify the code.

(Actually, I can modify the code, but the problem is that I'm not sure I
can find all the places this could happen in the code, so I'd like to
simply let the compiler do it.  If there is a way to have the compiler
generate an error every time it sees misalignment, that would also be OK,
but absolutely less optimal.)

PLEASE HELP!

Rob

---------------------------------------------------------------------
Rob Newberry
Director of Fajita Technology
Group Logic, Inc.

             reply	other threads:[~2001-07-24 14:24 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-07-24 14:24 Rob Newberry [this message]
2001-07-26 16:23 ` Alexandre Oliva

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