[{"id":17120,"web_url":"https://patchwork.libcamera.org/comment/17120/","msgid":"<221c0645-df3a-faad-a09b-d963e75809b2@ideasonboard.com>","date":"2021-05-22T16:32:34","subject":"Re: [libcamera-devel] [PATCH] test: byte-stream-buffer: Initialize\n\tdata array","submitter":{"id":86,"url":"https://patchwork.libcamera.org/api/people/86/","name":"Umang Jain","email":"umang.jain@ideasonboard.com"},"content":"Hi Niklas,\n\nThank you for the patch.\n\nOn 5/22/21 8:51 PM, Niklas Söderlund wrote:\n> Fix compiler warning about variable use before being initialized that\n> appears with gcc 11.1.0.\n>\n> test/byte-stream-buffer.cpp:31:63: error: ‘data’ may be used uninitialized [-Werror=maybe-uninitialized]\n>\n> Signed-off-by: Niklas Söderlund \nReviewed-by: Umang Jain \n> ---\n> test/byte-stream-buffer.cpp | 2 +-\n> 1 file changed, 1 insertion(+), 1 deletion(-)\n>\n> diff --git a/test/byte-stream-buffer.cpp b/test/byte-stream-buffer.cpp\n> index d606f146f6ef04ed..c911a863d27122ae 100644\n> --- a/test/byte-stream-buffer.cpp\n> +++ b/test/byte-stream-buffer.cpp\n> @@ -20,7 +20,7 @@ class ByteStreamBufferTest : public Test\n> protected:\n> \tint run()\n> \t{\n> -\t\tstd::array data;\n> +\t\tstd::array data = {};\n> \t\tunsigned int i;\n> \t\tuint32_t value;\n> \t\tint ret;","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 8C68CC3200\n\tfor ;\n\tSat, 22 May 2021 16:32:43 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id E6F2068919;\n\tSat, 22 May 2021 18:32:42 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 08E60601AA\n\tfor ;\n\tSat, 22 May 2021 18:32:41 +0200 (CEST)","from localhost.localdomain (unknown [103.251.226.203])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id DB7BB88F;\n\tSat, 22 May 2021 18:32:39 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"U6WqzUI6\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1621701160;\n\tbh=ftRrJ4W0tGJhJqGmeH74GKvVQgbl9tMFeJz1L+Kz8bA=;\n\th=Subject:To:References:From:Date:In-Reply-To:From;\n\tb=U6WqzUI6hja0u1Z+ADUC2S5FUl3LHS69COip39UN+4gYHyssHZEIjQu7r85vXZfdw\n\tdASgzxXACtU0ZIjS8n5umRAyJfBRzkSc8ExNmjlHffYGuUW0Sy8UfiBwy41Xbjo5LP\n\tOXoZMThKvl4u3v34zyihCpIhNHudDDx3qOuVh0eU=","To":"=?utf-8?q?Niklas_S=C3=B6derlund?= ,\n\tlibcamera-devel@lists.libcamera.org","References":"<20210522152132.2136700-1-niklas.soderlund@ragnatech.se>","From":"Umang Jain ","Message-ID":"<221c0645-df3a-faad-a09b-d963e75809b2@ideasonboard.com>","Date":"Sat, 22 May 2021 22:02:34 +0530","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101\n\tThunderbird/68.11.0","MIME-Version":"1.0","In-Reply-To":"<20210522152132.2136700-1-niklas.soderlund@ragnatech.se>","Content-Type":"text/plain; charset=utf-8; format=flowed","Content-Transfer-Encoding":"8bit","Content-Language":"en-US","Subject":"Re: [libcamera-devel] [PATCH] test: byte-stream-buffer: Initialize\n\tdata array","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":17121,"web_url":"https://patchwork.libcamera.org/comment/17121/","msgid":"","date":"2021-05-22T21:41:34","subject":"Re: [libcamera-devel] [PATCH] test: byte-stream-buffer: Initialize\n\tdata array","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Niklas,\n\nThank you for the patch.\n\nOn Sat, May 22, 2021 at 05:21:32PM +0200, Niklas Söderlund wrote:\n> Fix compiler warning about variable use before being initialized that\n> appears with gcc 11.1.0.\n> \n> test/byte-stream-buffer.cpp:31:63: error: ‘data’ may be used uninitialized [-Werror=maybe-uninitialized]\n\nI've installed gcc 11.1.0 to try and reproduce this (I was testing with\ngcc 11.0.1). Turns out I had to disable -Db_sanitize=address to get the\nerror. Not sure if it occurs with gcc 11.0.1 as it got replaced with\n11.1.0 and I don't want to recompile it :-) gcc 10.2.0 doesn't choke,\nneither with nor without -Db_sanitize=address.\n\nThe full error is:\n\n../../test/byte-stream-buffer.cpp: In member function ‘virtual int ByteStreamBufferTest::run()’:\n../../test/byte-stream-buffer.cpp:31:63: error: ‘data’ may be used uninitialized [-Werror=maybe-uninitialized]\n 31 | ByteStreamBuffer wbuf(data.data(), data.size());\n | ^\nIn file included from ../../test/byte-stream-buffer.cpp:8:\n/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/array:176:7: note: by argument 1 of type ‘const std::array*’ to ‘constexpr std::array<_Tp, _Nm>::size_type std::array<_Tp, _Nm>::size() const [with _Tp = unsigned char; long unsigned int _Nm = 100]’ declared here\n 176 | size() const noexcept { return _Nm; }\n | ^~~~\n../../test/byte-stream-buffer.cpp:23:42: note: ‘data’ declared here\n 23 | std::array data;\n |\n\nThis seems to be a false positive, the size() function returns _Nm,\nwhich is the second argument to the template and is hardcoded to 100.\nThe error disappears with the following change:\n\ndiff --git a/test/byte-stream-buffer.cpp b/test/byte-stream-buffer.cpp\nindex d606f146f6ef..312be615da50 100644\n--- a/test/byte-stream-buffer.cpp\n+++ b/test/byte-stream-buffer.cpp\n@@ -28,7 +28,8 @@ protected:\n \t\t/*\n \t\t * Write mode.\n \t\t */\n-\t\tByteStreamBuffer wbuf(data.data(), data.size());\n+\t\tsize_t s = data.size();\n+\t\tByteStreamBuffer wbuf(data.data(), s);\n\n \t\tif (wbuf.base() != data.data() || wbuf.size() != data.size() ||\n \t\t wbuf.offset() != 0 || wbuf.overflow()) {\n\nIt really looks like a compiler bug.\n\n> Signed-off-by: Niklas Söderlund \n> ---\n> test/byte-stream-buffer.cpp | 2 +-\n> 1 file changed, 1 insertion(+), 1 deletion(-)\n> \n> diff --git a/test/byte-stream-buffer.cpp b/test/byte-stream-buffer.cpp\n> index d606f146f6ef04ed..c911a863d27122ae 100644\n> --- a/test/byte-stream-buffer.cpp\n> +++ b/test/byte-stream-buffer.cpp\n> @@ -20,7 +20,7 @@ class ByteStreamBufferTest : public Test\n> protected:\n> \tint run()\n> \t{\n> -\t\tstd::array data;\n> +\t\tstd::array data = {};\n\nAs this is a test case, there's no issue in initializing the array.\nCould you however add a comment to explain this, to avoid someone\nremoving the initialization later by mistake ?\n\n\t\t/*\n\t\t * gcc 11.1.0 incorrectly raises a maybe-uninitialized warning\n\t\t * when calling data.size() below (if the address sanitizer is\n\t\t * disabled). Silence it by initializing the array.\n\t\t */\n\nReviewed-by: Laurent Pinchart \n\n> \t\tunsigned int i;\n> \t\tuint32_t value;\n> \t\tint ret;","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 3DEE7C3200\n\tfor ;\n\tSat, 22 May 2021 21:41:41 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 8C45C68919;\n\tSat, 22 May 2021 23:41:40 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 7A631601AA\n\tfor ;\n\tSat, 22 May 2021 23:41:39 +0200 (CEST)","from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi\n\t[62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 11FEA9AA;\n\tSat, 22 May 2021 23:41:38 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"E4sG6i8o\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1621719699;\n\tbh=Vk4kf7zuMOGuKMrG7m5PsRxh7hFN1cgJJCxxNCUu5Bc=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=E4sG6i8odBxcwmd4PAWNXeODDu+xua92ELKakQWXtHU9iuM4RpLJt3rMIITTJfgYI\n\t2BTh5V5dqtndySAEjIWfge84ZoYjLZs0xB5SGe/FkMsGiuHz53ju1cRmF5/RCFnfMR\n\tbXJuiBZ5brcDyAL2DpXFxGJj7KtpfX52Buv0XzHo=","Date":"Sun, 23 May 2021 00:41:34 +0300","From":"Laurent Pinchart ","To":"Niklas =?utf-8?q?S=C3=B6derlund?= ","Message-ID":"","References":"<20210522152132.2136700-1-niklas.soderlund@ragnatech.se>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"<20210522152132.2136700-1-niklas.soderlund@ragnatech.se>","Subject":"Re: [libcamera-devel] [PATCH] test: byte-stream-buffer: Initialize\n\tdata array","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera-devel@lists.libcamera.org","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]