{"id":15760,"url":"https://patchwork.libcamera.org/api/1.1/patches/15760/?format=json","web_url":"https://patchwork.libcamera.org/patch/15760/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20220429215841.19913-1-laurent.pinchart@ideasonboard.com>","date":"2022-04-29T21:58:41","name":"[libcamera-devel] libcamera: object: Silence gcc false positive error in release mode","commit_ref":"4f1d1a48fe7ebe1282d7608a59cb059e1367e584","pull_url":null,"state":"accepted","archived":false,"hash":"c65b311728314f60b9ae5153889c3f954b07049e","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/1.1/people/2/?format=json","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/15760/mbox/","series":[{"id":3085,"url":"https://patchwork.libcamera.org/api/1.1/series/3085/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=3085","date":"2022-04-29T21:58:41","name":"[libcamera-devel] libcamera: object: Silence gcc false positive error in release mode","version":1,"mbox":"https://patchwork.libcamera.org/series/3085/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/15760/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/15760/checks/","tags":{},"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 ECFCFC0F2A\n\tfor ;\n\tFri, 29 Apr 2022 21:58:48 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 645FB604A5;\n\tFri, 29 Apr 2022 23:58:48 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 130B46042F\n\tfor ;\n\tFri, 29 Apr 2022 23:58:46 +0200 (CEST)","from pendragon.lan (62-78-145-57.bb.dnainternet.fi [62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 820FE45F\n\tfor ;\n\tFri, 29 Apr 2022 23:58:45 +0200 (CEST)"],"DKIM-Signature":["v=1; 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dkim=pass (1024-bit key; \n\tunprotected) header.d=ideasonboard.com\n\theader.i=@ideasonboard.com\n\theader.b=\"p4IjbRuu\"; dkim-atps=neutral","To":"libcamera-devel@lists.libcamera.org","Date":"Sat, 30 Apr 2022 00:58:41 +0300","Message-Id":"<20220429215841.19913-1-laurent.pinchart@ideasonboard.com>","X-Mailer":"git-send-email 2.35.1","MIME-Version":"1.0","Content-Type":"text/plain; charset=UTF-8","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH] libcamera: object: Silence gcc false\n\tpositive error in release mode","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","From":"Laurent Pinchart via libcamera-devel\n\t","Reply-To":"Laurent Pinchart ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"gcc 10 and 11 produce an error when compiling libcamera in release mode:\n\nIn file included from ../../src/libcamera/base/object.cpp:13:\n../../include/libcamera/base/message.h: In member function ‘void libcamera::Object::notifyThreadMove()’:\n../../include/libcamera/base/message.h:58:47: error: array subscript ‘const libcamera::InvokeMessage[0]’ is partly outside array bounds of ‘libcamera::Message [1]’ [-Werror=array-bounds]\n 58 | Semaphore *semaphore() const { return semaphore_; }\n | ^~~~~~~~~~\n../../src/libcamera/base/object.cpp:280:17: note: while referencing ‘msg’\n 280 | Message msg(Message::ThreadMoveMessage);\n | ^~~\n\nThis seems to be a false positive, given that msg->type() can never be\nequal to Message::InvokeMessage in Object::message() when called from\nObject::notifyThreadMove(), as the message is created there with the\nMessage::ThreadMoveMessage type. The problem as been reported in\nhttps://gcc.gnu.org/bugzilla/show_bug.cgi?id=105400, but the error\nnonetheless needs to be fixed without waiting for a new gcc release, and\na dynamic_cast does the job with a small additional runtime cost that\nshouldn't be a big issue, given that moving objects between threads is a\nrare operation.\n\nBug: https://bugs.libcamera.org/show_bug.cgi?id=125\nSigned-off-by: Laurent Pinchart \n---\n src/libcamera/base/object.cpp | 6 +++++-\n 1 file changed, 5 insertions(+), 1 deletion(-)","diff":"diff --git a/src/libcamera/base/object.cpp b/src/libcamera/base/object.cpp\nindex ec5b55d125d1..92cecd22fbe9 100644\n--- a/src/libcamera/base/object.cpp\n+++ b/src/libcamera/base/object.cpp\n@@ -189,7 +189,11 @@ void Object::message(Message *msg)\n {\n \tswitch (msg->type()) {\n \tcase Message::InvokeMessage: {\n-\t\tInvokeMessage *iMsg = static_cast(msg);\n+\t\t/*\n+\t\t * A static_cast should be enough, but gcc 10 and 11 choke on\n+\t\t * it in release mode (with -O2 or -O3).\n+\t\t */\n+\t\tInvokeMessage *iMsg = dynamic_cast(msg);\n \t\tSemaphore *semaphore = iMsg->semaphore();\n \t\tiMsg->invoke();\n \n","prefixes":["libcamera-devel"]}