From patchwork Sun Sep 3 15:48:40 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 22596 Received: (qmail 93825 invoked by alias); 3 Sep 2017 15:48:48 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 93395 invoked by uid 89); 3 Sep 2017 15:48:47 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-25.0 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_SPAM, SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mail-oi0-f52.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=ohAzAI/44MUBgjYHLNbj4W/RGOBWS9EhkzKZIYryczI=; b=acvtS579UZj14BUN5RLvqRwtVr/qbx36zp6OZp2SAMtFmnEwkscULkiGNV5AXuX1q9 Bv51kT3KaFWb7tE86BI+KlUGzU53fzcTdYkFGHJkKeAWFZjDPy7hRzbhQX3IHFS1uXq8 L3m+vm3dWjIzYjjzWmoPoFNn3t4ACV/vIW6SKaGKlwxz4LoJ6V2Mt7GxtiRFo6X8iZlQ 5hysXP6lyUAnLdNTgWEvoL5WWvKjyw/+eDqFiIdqbDHTQSDgbbWkeBUSHAt8oSZg556S u6ThNmILv2EE8aejwR9+rA6DC66VTUe2W6uzzGhZ6xAvPXLtgjUBQXgAkPphxgmzF22v QM8A== X-Gm-Message-State: AHPjjUhvHJqpjaE4ioHmL4pmNhidu5OTBHJd9NgSYIz6ZCOTYUk0/GYt VDh8WeCpjUZTg/LPq08uqy/V5zUsIQ== X-Google-Smtp-Source: ADKCNb5A36zCTWVm6pxeawmLa+D8sddmdfMbl7DmqB3VFQfLW0QAl3hHuYtoVkDwscnzINCNDa+e/F+HSzz4JjDFYhw= X-Received: by 10.202.4.194 with SMTP id 185mr6675190oie.240.1504453721059; Sun, 03 Sep 2017 08:48:41 -0700 (PDT) MIME-Version: 1.0 From: "H.J. Lu" Date: Sun, 3 Sep 2017 08:48:40 -0700 Message-ID: Subject: [PATCH] Silence -O3 -Wall warning in malloc/hooks.c with GCC 7 [BZ #22052] To: Florian Weimer Cc: "Carlos O'Donell" , GNU C Library On Thu, Aug 31, 2017 at 10:01 AM, Florian Weimer wrote: > On 08/31/2017 05:55 AM, H.J. Lu wrote: > >> One of malloc change caused: >> >> https://sourceware.org/bugzilla/show_bug.cgi?id=22052 > > (uninit warning with -O3) > > I have not yet found a good way to suppress this. I don't know yet why > GCC loses the information that the maybe_p variable is initialized if > mem2chunk_check returns a non-null pointer. > This patch works for me. OK for master? From 735efe5ebc3eb6aa877b00b10ac0046524cee6e3 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Sun, 3 Sep 2017 08:39:55 -0700 Subject: [PATCH] Silence -O3 -Wall warning in malloc/hooks.c with GCC 7 [BZ #22052] MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit realloc_check has unsigned char *magic_p; ... __libc_lock_lock (main_arena.mutex); const mchunkptr oldp = mem2chunk_check (oldmem, &magic_p); __libc_lock_unlock (main_arena.mutex); if (!oldp) malloc_printerr ("realloc(): invalid pointer"); ... if (newmem == NULL) *magic_p ^= 0xFF; with static void malloc_printerr(const char *str) __attribute__ ((noreturn)); GCC 7 -O3 warns hooks.c: In function ‘realloc_check’: hooks.c:352:14: error: ‘magic_p’ may be used uninitialized in this function [-Werror=maybe-uninitialized] *magic_p ^= 0xFF; This patch silences GCC 7 by initializing magic_p to NULL. [BZ #22052] * malloc/hooks.c (realloc_check): Initialize magic_p to NULL. --- malloc/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/malloc/hooks.c b/malloc/hooks.c index 01be076f5e..03bc086901 100644 --- a/malloc/hooks.c +++ b/malloc/hooks.c @@ -287,7 +287,7 @@ realloc_check (void *oldmem, size_t bytes, const void *caller) { INTERNAL_SIZE_T nb; void *newmem = 0; - unsigned char *magic_p; + unsigned char *magic_p = NULL; if (bytes + 1 == 0) { -- 2.13.5