From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26345 invoked by alias); 10 Oct 2003 15:01:35 -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 26337 invoked from network); 10 Oct 2003 15:01:32 -0000 Received: from unknown (HELO mx1.redhat.com) (66.187.233.31) by sources.redhat.com with SMTP; 10 Oct 2003 15:01:32 -0000 Received: from int-mx2.corp.redhat.com (nat-pool-rdu-dmz.redhat.com [172.16.52.200] (may be forged)) by mx1.redhat.com (8.11.6/8.11.6) with ESMTP id h9AF1VM23780 for ; Fri, 10 Oct 2003 11:01:31 -0400 Received: from potter.sfbay.redhat.com (potter.sfbay.redhat.com [172.16.27.15]) by int-mx2.corp.redhat.com (8.11.6/8.11.6) with ESMTP id h9AF1VD26400 for ; Fri, 10 Oct 2003 11:01:31 -0400 Received: from cygbert.vinschen.de (vpn50-15.rdu.redhat.com [172.16.50.15]) by potter.sfbay.redhat.com (8.11.6/8.11.6) with ESMTP id h9AF1Ti16390 for ; Fri, 10 Oct 2003 08:01:29 -0700 Received: by cygbert.vinschen.de (Postfix, from userid 500) id B0A7C58047; Fri, 10 Oct 2003 17:01:27 +0200 (CEST) Date: Fri, 10 Oct 2003 15:01:00 -0000 From: Corinna Vinschen To: gdb-patches@sources.redhat.com Subject: Re: [RFA] sh-tdep.c (sh_use_struct_convention): Restructure and fix Message-ID: <20031010150127.GK14344@cygbert.vinschen.de> Reply-To: gdb-patches@sources.redhat.com Mail-Followup-To: gdb-patches@sources.redhat.com References: <20031004113939.GK11435@cygbert.vinschen.de> <16261.53197.951881.194874@localhost.redhat.com> <20031010072929.GF14344@cygbert.vinschen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20031010072929.GF14344@cygbert.vinschen.de> User-Agent: Mutt/1.4.1i X-SW-Source: 2003-10/txt/msg00358.txt.bz2 On Fri, Oct 10, 2003 at 09:29:29AM +0200, Corinna Vinschen wrote: > And even though I have to admit, that I'm not 100% sure (perhaps > I miss a case) I think the implementation should match at least 99% > of the description. > > The difference between the old and the new code is given by allowing > 4 byte structs (erm, aggregates) with more than one element, but a size > of 4 byte for the first element. This sounds somewhat weird, but that's > exactly the case if the 4 byte agregate is a bitfield or contains a > bitfield. So the change in this patch solves exactly these bitfields > as return type problem. ...and I just found out what this patch does *not* cover. It does not cover the case of bitfields of size 1 or 2 bytes :-( I rewrote the implementation of sh_use_struct_convention and tested it again. Below is the entire implementation instead of the patch. I think this is easier to read. I also tried to match the comments even better to the actual code. Is that ok to check in? Btw., this time, there *are* tests missing. The testsuite doesn't check for returning bitfield types of size 1 and 2 bytes. I'm going to add two tests to call-rt-st.exp which I hope to submit at least Monday. Corinna ========== SNIP =========== static int sh_use_struct_convention (int gcc_p, struct type *type) { int len = TYPE_LENGTH (type); int nelem = TYPE_NFIELDS (type); /* Non-power of 2 length types and types bigger than 8 bytes (which don't fit in two registers anyway) use struct convention. */ if (len != 1 && len != 2 && len != 4 && len != 8) return 1; /* Scalar types and aggregate types with exactly one field are aligned by definition. They are returned in registers. */ if (nelem <= 1) return 0; /* If the first field in the aggregate has the same length as the entire aggregate type, the type is returned in registers. */ if (TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) == len) return 0; /* If the size of the aggregate is 8 bytes and the first field is of size 4 bytes its alignment is equal to long long's alignment, so it's returned in registers. */ if (len == 8 && TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) == 4) return 0; /* Otherwise use struct convention. */ return 1; } ========== SNAP =========== -- Corinna Vinschen Cygwin Developer Red Hat, Inc.