From owner-freebsd-arch@FreeBSD.ORG Wed Nov 17 23:42:51 2010 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 636CA1065672; Wed, 17 Nov 2010 23:42:51 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from harmony.bsdimp.com (bsdimp.com [199.45.160.85]) by mx1.freebsd.org (Postfix) with ESMTP id 04D618FC15; Wed, 17 Nov 2010 23:42:50 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by harmony.bsdimp.com (8.14.3/8.14.1) with ESMTP id oAHNWJnq055509; Wed, 17 Nov 2010 16:32:19 -0700 (MST) (envelope-from imp@bsdimp.com) Message-ID: <4CE46602.9000303@bsdimp.com> Date: Wed, 17 Nov 2010 16:32:18 -0700 From: Warner Losh User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.2.12) Gecko/20101029 Thunderbird/3.1.6 MIME-Version: 1.0 To: John Baldwin References: <201007291718.12687.tijl@coosemans.org> <4CE417B3.3030102@bsdimp.com> <201011172058.05683.tijl@coosemans.org> <201011171718.37798.jhb@freebsd.org> In-Reply-To: <201011171718.37798.jhb@freebsd.org> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: Garrett Cooper , Warner Losh , Tijl Coosemans , Dimitry Andric , freebsd-arch@freebsd.org Subject: Re: Support for cc -m32 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Nov 2010 23:42:51 -0000 On 11/17/2010 15:18, John Baldwin wrote: > On Wednesday, November 17, 2010 2:57:51 pm Tijl Coosemans wrote: >> cc-m32-3.diff: >> Modify amd64 headers to include i386 headers when compiling 32 bit code. >> >> All amd64 headers follow the following format: >> >> #ifndef _AMD64_HEADER_H_ >> #define _AMD64_HEADER_H_ >> >> #ifdef __i386__ >> #include >> #else >> >> /* Amd64 declarations go here. */ >> >> #endif /* __i386__ */ >> #endif /* !_AMD64_HEADER_H_ */ > I find this to be really ugly, and error prone (since it is a manual process). > I'd prefer something that autogenerated headers in /usr/include/machine that > #include the appropriate version similar to what Warner suggested. > > However, one issue with that approach (and this one) are headers that only > exist for one platform. The end result would be that that header would now > exist for both platforms (in that if you do 'if [ -r > /usr/include/machine/foo.h ]' it will be true). We can make it #error or > otherwise fail (by including a non-existing file for example), but if there > was some way to have cc -m32 "magically" substitute "i386/" for "machine", > that is what I would most prefer. (This has problems too in that #include > would work with -m32 even though /usr/include/machine/foo.h > doesn't exist, but /usr/include/i386/foo.h does. "magically" converting machine -> i386 requires cpp hacking. However, the if [] test is beyond the scope of the API that we support. Scripts that use -m32 will have to cope with other issues. We could 'solve' this by having an /usr/include32, but even that still isn't complete. I contend that the least bad solution is to auto generate the machine directory from the sys/{i386,amd64}/include. If we do that, we could implement -m64 on i386 too, but that needs a lot more infrastructure. Warner