From patchwork Mon May 26 16:47:49 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Georg-Johann Lay X-Patchwork-Id: 352579 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id BE7291400A3 for ; Tue, 27 May 2014 02:45:43 +1000 (EST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender :message-id:date:from:mime-version:to:cc:subject:content-type :content-transfer-encoding; q=dns; s=default; b=REz2UXnWFV1MN+CW Rqh9Ld7IrtlO5gWvDkuxGcFH0/7caD563qTfyT0JmvFzW4D/4j0n5wb1NHhmDiFx arQzUjOEO35odBxWaA/mWIi6NfiFRhREM/Si4lPU799fTC04mAPPzJC+dfKGJQgu SxUW5ZPZB5KhU2mxo+0v8wBDaQM= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender :message-id:date:from:mime-version:to:cc:subject:content-type :content-transfer-encoding; s=default; bh=V0Zu6JoxRf/MK/9KuhZmZ7 ug1fo=; b=g48ITQlsL4HbIOe28cyYOdFYDBafgCYJsNJJbMabeIrgzKNHnxgCY3 g/YgcMXDRb5Tql78zAonorJPtdLTMMfHwxKR22q/cjWQBnVJNY/P9h0jOeq5Lg7n +LmrM0YFKKlHJ7mX4onWF5J9i4nRm3r1537Mw2Jwk72WIrBQRcLjA= Received: (qmail 20953 invoked by alias); 26 May 2014 16:45:36 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Received: (qmail 20942 invoked by uid 89); 26 May 2014 16:45:35 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 X-HELO: mo4-p00-ob.smtp.rzone.de Received: from mo4-p00-ob.smtp.rzone.de (HELO mo4-p00-ob.smtp.rzone.de) (81.169.146.216) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Mon, 26 May 2014 16:45:33 +0000 X-RZG-AUTH: :LXoWVUeid/7A29J/hMvvT3ol15ykJcYwRP/XHRipPRQwznuLpg== X-RZG-CLASS-ID: mo00 Received: from [192.168.0.22] (business-188-111-022-002.static.arcor-ip.net [188.111.22.2]) by smtp.strato.de (RZmta 34.2 AUTH) with ESMTPSA id j05e51q4QGjSO6m (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate); Mon, 26 May 2014 18:45:28 +0200 (CEST) Message-ID: <53837035.6030208@gjlay.de> Date: Mon, 26 May 2014 18:47:49 +0200 From: Georg-Johann Lay User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: GCC Patches CC: Denis Chertykov Subject: [patch, doc, avr] PR61044: Note that label defferences are not supported X-IsSubscribed: yes This adds a note to the user manual that code with label differences is not supported. This is because adding an offset to a stub address as generated with gs() will in general not yield the address of the label+offset. This actually occurs only if gs() has something to do, e.g. on devices with more than 128KiB of flash; but I don't see any benefit from supporting the feature on small devices -- left out all the problems caused by relaxing and when gas resolves the label difference. Thus, add a note that it's not available on any AVR and mark the PR as invalid. Ok for trunk? Johann PR target/61044 * doc/extend.texi (Local Labels): Note that label differences are not supported for AVR. Index: doc/extend.texi =================================================================== --- doc/extend.texi (revision 210936) +++ doc/extend.texi (working copy) @@ -373,6 +373,8 @@ goto *(&&foo + array[i]); This is more friendly to code living in shared libraries, as it reduces the number of dynamic relocations that are needed, and by consequence, allows the data to be read-only. +This alternative with label differences is not supported for the AVR target, +please use the first approach for AVR programs. The @code{&&foo} expressions for the same label might have different values if the containing function is inlined or cloned. If a program