From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gproxy2-pub.mail.unifiedlayer.com (gproxy2-pub.mail.unifiedlayer.com [69.89.18.3]) by sourceware.org (Postfix) with ESMTPS id 6DD7E3858425 for ; Tue, 20 Dec 2022 21:03:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 6DD7E3858425 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=tromey.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=tromey.com Received: from cmgw12.mail.unifiedlayer.com (unknown [10.0.90.127]) by progateway4.mail.pro1.eigbox.com (Postfix) with ESMTP id BFA41100476F7 for ; Tue, 20 Dec 2022 21:02:59 +0000 (UTC) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with ESMTP id 7jlLphBLqSbI37jlLp6ExD; Tue, 20 Dec 2022 21:02:59 +0000 X-Authority-Reason: nr=8 X-Authority-Analysis: v=2.4 cv=TfpTCTch c=1 sm=1 tr=0 ts=63a22303 a=ApxJNpeYhEAb1aAlGBBbmA==:117 a=ApxJNpeYhEAb1aAlGBBbmA==:17 a=dLZJa+xiwSxG16/P+YVxDGlgEgI=:19 a=IkcTkHD0fZMA:10:nop_charset_1 a=sHyYjHe8cH0A:10:nop_rcvd_month_year a=Qbun_eYptAEA:10:endurance_base64_authed_username_1 a=CCpqsmhAAAAA:8 a=lajzBTEP1nAlgUU_FtUA:9 a=QEXdDO2ut3YA:10:nop_charset_2 a=ul9cdbp4aOFLsgKbc677:22 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tromey.com; s=default; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Message-ID: In-Reply-To:Date:References:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=s/2vPTwqYUhYSF+si56e6MilZfSB6QXsTZkii9iFrMc=; b=tk3wCb+AoUv1tYBew3lwxgSmKY TyhnQbOMoVkcLVT5lg5L3mn/dzyur7C4Q/gLMNfpr+35m0Vi6QiSYhjGze4+Bi71BFj3kh8SKDava TBdgKcqHXZYZkJwZ2XErBfYeQ; Received: from 97-122-76-186.hlrn.qwest.net ([97.122.76.186]:46752 helo=murgatroyd) by box5379.bluehost.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1p7jlL-002NrM-34; Tue, 20 Dec 2022 14:02:59 -0700 From: Tom Tromey To: =?utf-8?Q?Torbj=C3=B6rn?= SVENSSON via Gdb-patches Cc: =?utf-8?Q?Torbj=C3=B6rn?= SVENSSON , , , Yvan Roux Subject: Re: [PATCH v2 3/4] gdb: dwarf2 generic implementation for caching function data References: <20221118155252.113476-1-torbjorn.svensson@foss.st.com> <20221118155252.113476-4-torbjorn.svensson@foss.st.com> X-Attribution: Tom Date: Tue, 20 Dec 2022 14:02:57 -0700 In-Reply-To: <20221118155252.113476-4-torbjorn.svensson@foss.st.com> (=?utf-8?Q?=22Torbj=C3=B6rn?= SVENSSON via Gdb-patches"'s message of "Fri, 18 Nov 2022 16:52:52 +0100") Message-ID: <87ili5kcu6.fsf@tromey.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - box5379.bluehost.com X-AntiAbuse: Original Domain - sourceware.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tromey.com X-BWhitelist: no X-Source-IP: 97.122.76.186 X-Source-L: No X-Exim-ID: 1p7jlL-002NrM-34 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 97-122-76-186.hlrn.qwest.net (murgatroyd) [97.122.76.186]:46752 X-Source-Auth: tom+tromey.com X-Email-Count: 1 X-Source-Cap: ZWx5bnJvYmk7ZWx5bnJvYmk7Ym94NTM3OS5ibHVlaG9zdC5jb20= X-Local-Domain: yes X-Spam-Status: No, score=-3022.2 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,JMQ_SPF_NEUTRAL,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: >>>>> Torbj=C3=B6rn SVENSSON via Gdb-patches w= rites: > When there is no dwarf2 data for a register, a function can be called > to provide the value of this register. In some situations, it might > not be trivial to determine the value to return and it would cause a > performance bottleneck to do the computation each time. Thanks for the patch. > This patch allows the called function to have a "cache" object that it > can use to store some metadata between calls to reduce the performance > impact of the complex logic. > The cache object is unique for each function and frame, so if there are > more than one function pointer stored in the dwarf2_frame_cache->reg > array, then the appropriate pointer will be supplied (the type is not > known by the dwarf2 implementation). Does this ever happen? If not perhaps a simpler approach would be better. > +struct dwarf2_frame_fn_data > +{ New type should have a comment. > + struct value *(*fn) (frame_info_ptr this_frame, void **this_cache, > + int regnum); Shouldn't this use the fn_prev_register typedef? > + void *data; > + struct dwarf2_frame_fn_data* next; Wrong placement of the "*", but really a lot of the code isn't following the GNU / gdb style. > +void *dwarf2_frame_get_fn_data (frame_info_ptr this_frame, void **this_c= ache, > + fn_prev_register fn) Normally new functions get a comment referring to the header where they are declared. > + > +/* Allocate a new instance of the function unique data. */ > + > +extern void *dwarf2_frame_allocate_fn_data (frame_info_ptr this_frame, > + void **this_cache, > + fn_prev_register fn, > + unsigned long size); > + > +/* Retrieve the function unique data for this frame. */ > + > +extern void *dwarf2_frame_get_fn_data (frame_info_ptr this_frame, I think these comments could perhaps be expanded a bit. Tom