From patchwork Fri May 7 09:38:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierre-Marie de Rodat X-Patchwork-Id: 1475419 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=8.43.85.97; helo=sourceware.org; envelope-from=gcc-patches-bounces@gcc.gnu.org; receiver=) Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4Fc5446sPmz9sj5 for ; Fri, 7 May 2021 19:38:44 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 2AC3A3939C03; Fri, 7 May 2021 09:38:29 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from rock.gnat.com (rock.gnat.com [205.232.38.15]) by sourceware.org (Postfix) with ESMTP id 9A9B238930FF for ; Fri, 7 May 2021 09:38:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 9A9B238930FF Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=derodat@adacore.com Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 08C5856355; Fri, 7 May 2021 05:38:23 -0400 (EDT) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Vc5Kz65vlmdO; Fri, 7 May 2021 05:38:22 -0400 (EDT) Received: from tron.gnat.com (tron.gnat.com [IPv6:2620:20:4000:0:46a8:42ff:fe0e:e294]) by rock.gnat.com (Postfix) with ESMTP id E87C856357; Fri, 7 May 2021 05:38:22 -0400 (EDT) Received: by tron.gnat.com (Postfix, from userid 4862) id E7CB2FA; Fri, 7 May 2021 05:38:22 -0400 (EDT) Date: Fri, 7 May 2021 05:38:22 -0400 From: Pierre-Marie de Rodat To: gcc-patches@gcc.gnu.org Subject: [Ada] Minor efficiency improvement in containers Message-ID: <20210507093822.GA140583@adacore.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Status: No, score=-12.5 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bob Duff Errors-To: gcc-patches-bounces@gcc.gnu.org Sender: "Gcc-patches" Move an assertion to be conditional on T_Check, so pragma Suppress (Tampering_Checks) will suppress it. Note that the Lock component being checked has the Atomic aspect. This is not a bug fix. Tested on x86_64-pc-linux-gnu, committed on trunk gcc/ada/ * libgnat/a-conhel.adb (TC_Check): Move the Assert into the 'if'. diff --git a/gcc/ada/libgnat/a-conhel.adb b/gcc/ada/libgnat/a-conhel.adb --- a/gcc/ada/libgnat/a-conhel.adb +++ b/gcc/ada/libgnat/a-conhel.adb @@ -122,17 +122,20 @@ package body Ada.Containers.Helpers is procedure TC_Check (T_Counts : Tamper_Counts) is begin - if T_Check and then T_Counts.Busy > 0 then - raise Program_Error with - "attempt to tamper with cursors"; + if T_Check then + if T_Counts.Busy > 0 then + raise Program_Error with + "attempt to tamper with cursors"; + end if; + + -- The lock status (which monitors "element tampering") always + -- implies that the busy status (which monitors "cursor + -- tampering") is set too; this is a representation invariant. + -- Thus if the busy count is zero, then the lock count + -- must also be zero. + + pragma Assert (T_Counts.Lock = 0); end if; - - -- The lock status (which monitors "element tampering") always - -- implies that the busy status (which monitors "cursor tampering") - -- is set too; this is a representation invariant. Thus if the busy - -- bit is not set, then the lock bit must not be set either. - - pragma Assert (T_Counts.Lock = 0); end TC_Check; --------------