From nobody Wed Oct 15 07:25:27 2025 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4cmjKh0JgZz6Csbt; Wed, 15 Oct 2025 07:25:28 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cmjKg4x0Kz3RJH; Wed, 15 Oct 2025 07:25:27 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1760513127; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=+kb0Wp1+QU42zulFckUxFavf8yJfiedoFCpvwEVGabg=; b=f7Lt+Y8GtPGiNUiv7r6HVD9TH9huxnX3zuXrD4mbisrPpU5pgQcVZHHxItPisB4b9ozgHN L5HRtv94wrRGh8JyWwiLefFW5FcPRGrZ4N1AVC/r19tO6ipS3Y/5cnLz/LVhOeMgNpQLcL aI1pdmEMd8uCOir1fdOx1sP6AAw0ZAIiTWqY3dnVWZ0M7q4d61z4dfAp2gwxQ/5xLFjCPC 7ZN0jXDMkQLnaZhOJrXRk68m9MbKh7/8KV1ytntoqU347xu9I0T/PKlOnFwFkDZpoFIo+I sKHC2MzLhdhxE4ERVxMDyYWiTfi5LFFpWengDK0yirgxYBI9k2WB5l3+js4jCA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1760513127; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=+kb0Wp1+QU42zulFckUxFavf8yJfiedoFCpvwEVGabg=; b=wZU6DJRnzMNN4ieD5GGYcusDSnofZ25b0iL/z+mHLCd5vOQireb+x8m3cVtbM2fTp1BkzA GtFUjA1459Acp+QvD5I5Nt/4F+/LJXvNObs/C3WS44PDfPeGuaDyampVqegIrZDAbkTKBy WZC5UU52189fkPnbdPOWsj55czI+GRcNg/zyfdXYTzPwQIcdull4MaKMpPxAhMY5Xc9CNq yCuNYAQ7MYGPHf2qXzH3lTFzArlBAth8l9G4+Ul7niCAh5CyTsx+HypW56mW74w7gHA/ps TTLSDcvjAjegwowKTsQkHxgH7AYth+t/jJPKsCx3M5O/ERVAxTtDMdRI7r9yRg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1760513127; a=rsa-sha256; cv=none; b=v/HU21dXYNWnPnd3zAkR/INcPXW1Qc894bXr8Y0bSX67DK34FhoAQG3BaPOlj8AUFBPn9T XBdYQaVuN8iVXzsaduJGgb3yaC8dFKz0bz4LDe+feyQiTefGurWOc74ErDJkUQrkFjNXDN 8Fys+XqGMMd4nT0703LqrcEba4NcG7DNHVzc08j1o36yLhnMZ2xZUN8Whj87k4oMF/EwWp JwjXRsmguLQB5tDRUc5HGVzDawb5hwMP5aWVQLGhoj1YXrnJf7BABWDh+PrAjSlPnePfTe UWQu61Ouo8vSbqjrdQfg2OIwJ5EwDR6kRkHOhUXkpMzqm1mZ417sO8u8Rhk34Q== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4cmjKg4NlYzCvQ; Wed, 15 Oct 2025 07:25:27 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 59F7PRQ3072463; Wed, 15 Oct 2025 07:25:27 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 59F7PRrN072460; Wed, 15 Oct 2025 07:25:27 GMT (envelope-from git) Date: Wed, 15 Oct 2025 07:25:27 GMT Message-Id: <202510150725.59F7PRrN072460@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Ryan Libby Subject: git: c44d2663a790 - main - rb tree: remove strict aliasing violations List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: rlibby X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: c44d2663a790b31bc1cd08958b45a661487c0287 Auto-Submitted: auto-generated The branch main has been updated by rlibby: URL: https://cgit.FreeBSD.org/src/commit/?id=c44d2663a790b31bc1cd08958b45a661487c0287 commit c44d2663a790b31bc1cd08958b45a661487c0287 Author: Ryan Libby AuthorDate: 2025-10-15 04:05:19 +0000 Commit: Ryan Libby CommitDate: 2025-10-15 06:44:47 +0000 rb tree: remove strict aliasing violations Rework internal RB macros to avoid assignments via type punned pointers. RB uses low order pointer bits to encode information (whether children are red), and was manipulating those values via (*(__uintptr_t *)&elm), which leads to strict aliasing warnings. In the kernel we use -fno-strict-aliasing, but this isn't necessarily the case in user space. This quiets thousands of -Wstrict-aliasing warnings in the user space build. Reported by: GCC -Wstrict-aliasing Reviewed by: dougm Discussed with: kib Differential Revision: https://reviews.freebsd.org/D52939 --- sys/sys/tree.h | 57 ++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 34 insertions(+), 23 deletions(-) diff --git a/sys/sys/tree.h b/sys/sys/tree.h index c11bccfb387c..194ad505b038 100644 --- a/sys/sys/tree.h +++ b/sys/sys/tree.h @@ -334,10 +334,13 @@ struct { \ #define _RB_L ((__uintptr_t)1) #define _RB_R ((__uintptr_t)2) #define _RB_LR ((__uintptr_t)3) -#define _RB_BITS(elm) (*(__uintptr_t *)&elm) +#define _RB_BITS(elm) ((__uintptr_t)elm) #define _RB_BITSUP(elm, field) _RB_BITS(_RB_UP(elm, field)) -#define _RB_PTR(elm) (__typeof(elm)) \ - ((__uintptr_t)elm & ~_RB_LR) +#define _RB_PTR_OP(elm, op, dir) ((__typeof(elm)) \ + ((__uintptr_t)(elm) op (dir))) +#define _RB_PTR(elm) _RB_PTR_OP((elm), &, ~_RB_LR) +#define _RB_MOD_OR(elm, dir) ((elm) = _RB_PTR_OP((elm), |, (dir))) +#define _RB_MOD_XOR(elm, dir) ((elm) = _RB_PTR_OP((elm), ^, (dir))) #define RB_PARENT(elm, field) _RB_PTR(_RB_UP(elm, field)) #define RB_LEFT(elm, field) _RB_LINK(elm, _RB_L, field) @@ -346,8 +349,8 @@ struct { \ #define RB_EMPTY(head) (RB_ROOT(head) == NULL) #define RB_SET_PARENT(dst, src, field) do { \ - _RB_BITSUP(dst, field) = (__uintptr_t)src | \ - (_RB_BITSUP(dst, field) & _RB_LR); \ + _RB_UP(dst, field) = (__typeof(src))((__uintptr_t)src | \ + (_RB_BITSUP(dst, field) & _RB_LR)); \ } while (/*CONSTCOND*/ 0) #define RB_SET(elm, parent, field) do { \ @@ -546,12 +549,12 @@ name##_RB_INSERT_COLOR(struct name *head, \ elmdir = RB_RIGHT(parent, field) == elm ? _RB_R : _RB_L; \ if (_RB_BITS(gpar) & elmdir) { \ /* shorten the parent-elm edge to rebalance */ \ - _RB_BITSUP(parent, field) ^= elmdir; \ + _RB_MOD_XOR(_RB_UP(parent, field), elmdir); \ return (NULL); \ } \ sibdir = elmdir ^ _RB_LR; \ /* the other edge must change length */ \ - _RB_BITSUP(parent, field) ^= sibdir; \ + _RB_MOD_XOR(_RB_UP(parent, field), sibdir); \ if ((_RB_BITS(gpar) & _RB_LR) == 0) { \ /* both edges now short, retry from parent */ \ child = elm; \ @@ -583,11 +586,14 @@ name##_RB_INSERT_COLOR(struct name *head, \ RB_ROTATE(elm, child, elmdir, field); \ child_up = _RB_UP(child, field); \ if (_RB_BITS(child_up) & sibdir) \ - _RB_BITSUP(parent, field) ^= elmdir; \ + _RB_MOD_XOR(_RB_UP(parent, field), \ + elmdir); \ if (_RB_BITS(child_up) & elmdir) \ - _RB_BITSUP(elm, field) ^= _RB_LR; \ + _RB_MOD_XOR(_RB_UP(elm, field), \ + _RB_LR); \ else \ - _RB_BITSUP(elm, field) ^= elmdir; \ + _RB_MOD_XOR(_RB_UP(elm, field), \ + elmdir); \ /* if child is a leaf, don't augment elm, \ * since it is restored to be a leaf again. */ \ if ((_RB_BITS(child_up) & _RB_LR) == 0) \ @@ -656,7 +662,7 @@ name##_RB_REMOVE_COLOR(struct name *head, \ /* the rank of the tree rooted at elm shrank */ \ gpar = _RB_UP(parent, field); \ elmdir = RB_RIGHT(parent, field) == elm ? _RB_R : _RB_L; \ - _RB_BITS(gpar) ^= elmdir; \ + _RB_MOD_XOR(gpar, elmdir); \ if (_RB_BITS(gpar) & elmdir) { \ /* lengthen the parent-elm edge to rebalance */ \ _RB_UP(parent, field) = gpar; \ @@ -664,7 +670,7 @@ name##_RB_REMOVE_COLOR(struct name *head, \ } \ if (_RB_BITS(gpar) & _RB_LR) { \ /* shorten other edge, retry from parent */ \ - _RB_BITS(gpar) ^= _RB_LR; \ + _RB_MOD_XOR(gpar, _RB_LR); \ _RB_UP(parent, field) = gpar; \ gpar = _RB_PTR(gpar); \ continue; \ @@ -672,7 +678,7 @@ name##_RB_REMOVE_COLOR(struct name *head, \ sibdir = elmdir ^ _RB_LR; \ sib = _RB_LINK(parent, sibdir, field); \ up = _RB_UP(sib, field); \ - _RB_BITS(up) ^= _RB_LR; \ + _RB_MOD_XOR(up, _RB_LR); \ if ((_RB_BITS(up) & _RB_LR) == 0) { \ /* shorten edges descending from sib, retry */ \ _RB_UP(sib, field) = up; \ @@ -703,24 +709,29 @@ name##_RB_REMOVE_COLOR(struct name *head, \ /* elm is a 1-child. First rotate at elm. */ \ RB_ROTATE(sib, elm, sibdir, field); \ up = _RB_UP(elm, field); \ - _RB_BITSUP(parent, field) ^= \ - (_RB_BITS(up) & elmdir) ? _RB_LR : elmdir; \ - _RB_BITSUP(sib, field) ^= \ - (_RB_BITS(up) & sibdir) ? _RB_LR : sibdir; \ - _RB_BITSUP(elm, field) |= _RB_LR; \ + _RB_MOD_XOR(_RB_UP(parent, field), \ + (_RB_BITS(up) & elmdir) ? _RB_LR : elmdir); \ + _RB_MOD_XOR(_RB_UP(sib, field), \ + (_RB_BITS(up) & sibdir) ? _RB_LR : sibdir); \ + _RB_MOD_OR(_RB_UP(elm, field), _RB_LR); \ } else { \ if ((_RB_BITS(up) & elmdir) == 0 && \ RB_STRICT_HST && elm != NULL) { \ /* if parent does not become a leaf, \ do not demote parent yet. */ \ - _RB_BITSUP(parent, field) ^= sibdir; \ - _RB_BITSUP(sib, field) ^= _RB_LR; \ + _RB_MOD_XOR(_RB_UP(parent, field), \ + sibdir); \ + _RB_MOD_XOR(_RB_UP(sib, field), \ + _RB_LR); \ } else if ((_RB_BITS(up) & elmdir) == 0) { \ /* demote parent. */ \ - _RB_BITSUP(parent, field) ^= elmdir; \ - _RB_BITSUP(sib, field) ^= sibdir; \ + _RB_MOD_XOR(_RB_UP(parent, field), \ + elmdir); \ + _RB_MOD_XOR(_RB_UP(sib, field), \ + sibdir); \ } else \ - _RB_BITSUP(sib, field) ^= sibdir; \ + _RB_MOD_XOR(_RB_UP(sib, field), \ + sibdir); \ elm = sib; \ } \ \