From patchwork Fri Nov 3 03:19:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Marchi X-Patchwork-Id: 78970 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 693F13858408 for ; Fri, 3 Nov 2023 03:19:46 +0000 (GMT) X-Original-To: gdb-patches@sourceware.org Delivered-To: gdb-patches@sourceware.org Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id A11033858D39 for ; Fri, 3 Nov 2023 03:19:24 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org A11033858D39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=polymtl.ca Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=polymtl.ca ARC-Filter: OpenARC Filter v1.0.0 sourceware.org A11033858D39 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=132.207.4.11 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698981574; cv=none; b=KMB8f7nYKsA1VTZL3piXrzjPuC4UUJhZWLL6A3hiTvoUdTYbWCtywWlscw5ZykLq0J3W++kXKnev51jxpqhUJWwOqmeKpgnngAO/1jSXXUGS3Ljak2QukzDBLsTJX/SorA9wGZeQ9P+VM4OYs29A0a8OZbHELQ/KzXN6Am1DTZE= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698981574; c=relaxed/simple; bh=MTTJjFgciZTC+9cLO3qfp7JvvkVAeEbEvQfDWA5TmOM=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=D2uLlwlOwn9pS1uP15CCxJLufvHhJoE7d3Dj3UGm5kK4sr3u7eg2FAKOdfqIM9RmMN3zfaTpE3/z5CE/XOJyrip1ZCFzV3pXebEVLqJoL07qkE9W+NqGjL5RHRkm2RlxewajYn+oZbmC7aBtU6eKuT2RxWMCfcO7c2jmJQDeUs4= ARC-Authentication-Results: i=1; server2.sourceware.org Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 3A33JIAd012632 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 2 Nov 2023 23:19:22 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 3A33JIAd012632 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=polymtl.ca; s=default; t=1698981563; bh=ZE6gLorVE1rjOOvq9Qz09uC98s+R9HSTlzaxtI/ITN8=; h=From:To:Cc:Subject:Date:From; b=JYU8zMQNgmHp6I122kujLli9w0eqlGF++e6lbQc1yZiZWfIY56B9E5TtxihmXeUDg +ZjJ4S9VkGwe0bTe2niUzQKYEwugO89AKomFH+wPWcm7rsCRyZinPcY7duf1KXOb3Q IBiyrYmgoXNzLdRHnfoVxSU4kS/IHlJ8sMagyd4w= Received: from simark.localdomain (modemcable238.237-201-24.mc.videotron.ca [24.201.237.238]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id EAA761E0C1; Thu, 2 Nov 2023 23:19:17 -0400 (EDT) From: Simon Marchi To: gdb-patches@sourceware.org Cc: Simon Marchi Subject: [PATCH] gdbsupport: mark array_view::slice with [[nodiscard]] Date: Thu, 2 Nov 2023 23:19:09 -0400 Message-ID: <20231103031917.927026-1-simon.marchi@polymtl.ca> X-Mailer: git-send-email 2.42.0 MIME-Version: 1.0 X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Fri, 3 Nov 2023 03:19:18 +0000 X-Spam-Status: No, score=-3188.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org From: Simon Marchi I (almost) had a bug where I did: buffer.slice (...) but I meant: buffer = buffer.slice (...) The first one does nothing, it creates a new array_view but without using it, it's useless. Mark the slice methods with [[nodiscard]] (which is standard C++17) so that error would generate a warning. I guess that many functions could be marked as nodiscard, essentially function that is pure (doesn't have side-effects). But this one seems particularly easy to mis-use. Change-Id: Ib39a0a65a5728a3cfd68a02ae31635810baeaccb --- gdbsupport/array-view.h | 2 ++ 1 file changed, 2 insertions(+) base-commit: 268109cad16c692e24a583c21ef5a8ac58cc51fe diff --git a/gdbsupport/array-view.h b/gdbsupport/array-view.h index ee3a3c58710c..4b519112e78f 100644 --- a/gdbsupport/array-view.h +++ b/gdbsupport/array-view.h @@ -185,6 +185,7 @@ class array_view /* Slice an array view. */ /* Return a new array view over SIZE elements starting at START. */ + [[nodiscard]] constexpr array_view slice (size_type start, size_type size) const noexcept { #if defined(_GLIBCXX_DEBUG) && __cplusplus >= 201402L @@ -195,6 +196,7 @@ class array_view /* Return a new array view over all the elements after START, inclusive. */ + [[nodiscard]] constexpr array_view slice (size_type start) const noexcept { #if defined(_GLIBCXX_DEBUG) && __cplusplus >= 201402L