From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18692 invoked by alias); 22 Oct 2003 22:32:59 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 18685 invoked from network); 22 Oct 2003 22:32:57 -0000 Received: from unknown (HELO localhost.redhat.com) (207.219.125.105) by sources.redhat.com with SMTP; 22 Oct 2003 22:32:57 -0000 Received: from redhat.com (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id AF8B32B89; Wed, 22 Oct 2003 18:32:56 -0400 (EDT) Message-ID: <3F970598.9020908@redhat.com> Date: Wed, 22 Oct 2003 22:32:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-US; rv:1.0.2) Gecko/20030820 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jim Blandy Cc: gdb-patches@sources.redhat.com, Kris Warkentin , Daniel Jacobowitz Subject: Re: RFA: osabi: correct test for compatible handlers References: <3F96D128.5040904@redhat.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2003-10/txt/msg00662.txt.bz2 > Andrew Cagney writes: > > >> > + /* BFD's 'A->compatible (A, B)' functions return zero if A and B are >> > + incompatible. But if they are compatible, it returns the 'more >> > + featureful' of the two arches. That is, if A can run code >> > + written for B, but B can't run code written for A, then it'll >> > + return A. >> > + + struct bfd_arch_info objects are atoms: that is, there's >> > supposed >> > + to be exactly one instance for a given machine. So you can tell >> > + whether two are equivalent by comparing pointers. */ >> > + return (a == b || a->compatible (a, b) == a); > >> >> Hey, nice. >> >> Don't worry about a can_run_code_for function though, having the logic >> inline makes what's happening easier to understand (and will simplify >> a follow-on wild-card patch I've got pending). > > > It may be easier for you, but the original author did get the test > backwards, and I had to go through an embarrassing number of wrong > tries before I got it right. I'd really like to leave the function > separate. I had to go through an equally enbarrassing number of tries before I established exactly what the patch was doing. Changing: if (compatible == handler->arch_info) to: if (compatible == arch_info) (correct?) The really important thing here is your commentary as that explains exactly what is going on. Having it as close as possible to the problem (the call site) is, I think, going to make things easier to understand. Andrew