From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mo4-p00-ob.smtp.rzone.de (mo4-p00-ob.smtp.rzone.de [85.215.255.22]) by sourceware.org (Postfix) with ESMTPS id C37F43858D35; Sat, 15 Jan 2022 13:56:55 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C37F43858D35 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=nieper-wisskirchen.de Authentication-Results: sourceware.org; spf=none smtp.mailfrom=nieper-wisskirchen.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1642255014; s=strato-dkim-0002; d=nieper-wisskirchen.de; h=Cc:To:Subject:Message-ID:Date:From:In-Reply-To:References:Cc:Date: From:Subject:Sender; bh=7z4ks22MTCtA2dIgFSMIgRocsmwMI8FH0zY65mlCK7E=; b=ZsAYxWVwbe/OvJvsVCzvH80TJVgo5yv9UunGVUYmBxlv1wC4RqwHgis6M5IAT0Z/wI 2fvQoWB0zeQruvU4SUPQJOZtUiANtVsBk+eNaX9w4qCuk906KJM0/MM6MzS8yGRaUm7+ /bpg2ed8HwtO258I89wnkM94ClUOp304UBT/swWJnLu1vIa7JxbSXZfLG9xKAZduNM0V v0WrydD8CQW0Yk5v43VhSK5HBnhmfZj+Gmu4Pg96KUvwb3Ylmho0k130Nd7mBGIMYAKs o6imKed2bzcFOU6hD+uXQCIKjDE5hveXDaVLpsQExKxS/w2VMoClUsAv0JoyXiIB7gXR 1pcQ== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":IW0WdmCmcvpIrP2+VJuPtIhjJvc4Ig+QdhX22iZVwSDOx4Kp3cYsBVGy6CZgmO/guIaKV8N565JGDQ==" X-RZG-CLASS-ID: mo00 Received: from mail-yb1-f175.google.com by smtp.strato.de (RZmta 47.37.6 AUTH) with ESMTPSA id k693bey0FDurwrO (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Sat, 15 Jan 2022 14:56:53 +0100 (CET) Received: by mail-yb1-f175.google.com with SMTP id m196so3588594ybf.4; Sat, 15 Jan 2022 05:56:53 -0800 (PST) X-Gm-Message-State: AOAM533JvX1TwsJ/zZksHI1j0/rU17mTmvr+/eoE81q3/fq1NIbr4KK9 /I+ITdS1eg+KSLbLyeICxZtZpTrY9Yi0GxNuvrs= X-Google-Smtp-Source: ABdhPJzG6NZupY58yQvPtKNs2LbNgU9rodvQnPant6D/pyeyRspf1BGlAOlLrxdQ02G4YDlBsIXCW0p89IFJAbk4+EM= X-Received: by 2002:a25:6891:: with SMTP id d139mr1565067ybc.215.1642255012950; Sat, 15 Jan 2022 05:56:52 -0800 (PST) MIME-Version: 1.0 References: <20211219213010.17113-1-marc@nieper-wisskirchen.de> <2a54fac9b37d87afb009b8eb339d5ad6927454dd.camel@redhat.com> In-Reply-To: From: =?UTF-8?Q?Marc_Nieper=2DWi=C3=9Fkirchen?= Date: Sat, 15 Jan 2022 14:56:41 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] gcc: pass-manager: Fix memory leak. [PR jit/63854] To: Jeff Law Cc: David Malcolm , gcc-patches@gcc.gnu.org, =?UTF-8?Q?Marc_Nieper=2DWi=C3=9Fkirchen_via_Jit?= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-3.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: jit@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Jit mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 15 Jan 2022 13:57:06 -0000 Jeff, David, do you need any more input from my side? -- Marc Am Sa., 8. Jan. 2022 um 17:32 Uhr schrieb Jeff Law : > > > > On 1/6/2022 6:53 AM, David Malcolm via Gcc-patches wrote: > > On Sun, 2021-12-19 at 22:30 +0100, Marc Nieper-Wi=C3=9Fkirchen wrote: > >> This patch fixes a memory leak in the pass manager. In the existing > >> code, > >> the m_name_to_pass_map is allocated in > >> pass_manager::register_pass_name, but > >> never deallocated. This is fixed by adding a deletion in > >> pass_manager::~pass_manager. Moreover the string keys in > >> m_name_to_pass_map are > >> all dynamically allocated. To free them, this patch adds a new hash > >> trait for > >> string hashes that are to be freed when the corresponding hash entry > >> is removed. > >> > >> This fix is particularly relevant for using GCC as a library through > >> libgccjit. > >> The memory leak also occurs when libgccjit is instructed to use an > >> external > >> driver. > >> > >> Before the patch, compiling the hello world example of libgccjit with > >> the external driver under Valgrind shows a loss of 12,611 (48 direct) > >> bytes. After the patch, no memory leaks are reported anymore. > >> (Memory leaks occurring when using the internal driver are mostly in > >> the driver code in gcc/gcc.c and have to be fixed separately.) > >> > >> The patch has been tested by fully bootstrapping the compiler with > >> the > >> frontends C, C++, Fortran, LTO, ObjC, JIT and running the test suite > >> under a x86_64-pc-linux-gnu host. > > Thanks for the patch. > > > > It looks correct to me, given that pass_manager::register_pass_name > > does an xstrdup and puts the result in the map. > > > > That said: > > - I'm not officially a reviewer for this part of gcc (though I probably > > touched this code last) > > - is it cleaner to instead change m_name_to_pass_map's key type from > > const char * to char *, to convey that the map "owns" the name? That > > way we probably wouldn't need struct typed_const_free_remove, and (I > > hope) works better with the type system. > > > > Dave > > > >> gcc/ChangeLog: > >> > >> PR jit/63854 > >> * hash-traits.h (struct typed_const_free_remove): New. > >> (struct free_string_hash): New. > >> * pass_manager.h: Use free_string_hash. > >> * passes.c (pass_manager::register_pass_name): Use > >> free_string_hash. > >> (pass_manager::~pass_manager): Delete allocated > >> m_name_to_pass_map. > My concern (and what I hadn't had time to dig into) was we initially > used nofree_string_hash -- I wanted to make sure there wasn't any path > where the name came from the stack (can't be free'd), was saved > elsewhere (danging pointer) and the like. ie, why were we using > nofree_string_hash to begin with? I've never really mucked around with > these bits, so the analysis side kept falling off the daily todo list. > > If/once you're comfortable with the patch David, then go ahead and apply > it on Marc's behalf. > > jeff >