From patchwork Mon Dec 2 17:33:32 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Mailhol via B4 Relay X-Patchwork-Id: 13891147 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 621B11DDC28; Mon, 2 Dec 2024 17:35:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733160905; cv=none; b=i0OVKdbAwLnWB74D244LdFP6vzwPaemWCm2mEKGS19+3GbXIhiLpmKKe2k+R9kgTBsCgJK3WVOJyOrxn0Z3hyFNotMrvcXIWNAnMk++P2ZkdEejSmFkUDwT8hOMeBHJ/b1RMYOqxbcSpNa/MHV8gWybMJin3ZBvyNJN9wcASFUM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733160905; c=relaxed/simple; bh=uAZMv8YsD+O3wlShIE66KqQtYXWRRt5F/8DqFrLry7o=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WYyBZRxQ3QlyoZtQmFc/K3S6ugFKs9ELIrYZ2MqnJJke3W55P8AGfdSGsjzRZWQllYcJSRMsim4NrCHsCvzy/nngLH0ydzdhr5NagfgiSOAmiRu2pvVfD6tJ11MjEcZq7cUTmFRyLTvUcVxqrdjrCYQwdm/XQCmAz/Cf/hJ15ME= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bnpeLmKT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bnpeLmKT" Received: by smtp.kernel.org (Postfix) with ESMTPS id EE828C4AF0C; Mon, 2 Dec 2024 17:35:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733160905; bh=uAZMv8YsD+O3wlShIE66KqQtYXWRRt5F/8DqFrLry7o=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=bnpeLmKTZ0P/1nIlgfq6P/89fGBp79XUw1RuAsTRlXRHCp2izeFvyG+TI1GSO6Kkj +vSOTNpWal9tOo9dbUTbh9ga3NCi42/NymrTLb22Q4h+u/cokTPsWtrlid/tRFM1T1 6dV8OjkixQG4eXBo6SkrUV3AeE/R4D8dTZFDlu9F64ELfy0Kyibo9a/OngDbjQ2PZS fRCmDaWTk6tZnYjK8xTrQZoanmydKBBAOMVkExgd7RD1+VOe0fYp5Yw3cTebcM93v7 5dsvx+CeiiRXTK43GkDDCdvLdYPnost8GIN8ypR562MwwNxO1YQn1QxI+326LAvREB 1xToeg5fGWCxA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id E082BD7833D; Mon, 2 Dec 2024 17:35:04 +0000 (UTC) From: Vincent Mailhol via B4 Relay Date: Tue, 03 Dec 2024 02:33:32 +0900 Subject: [PATCH 10/10] compiler.h: remove __is_constexpr() Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241203-is_constexpr-refactor-v1-10-4e4cbaecc216@wanadoo.fr> References: <20241203-is_constexpr-refactor-v1-0-4e4cbaecc216@wanadoo.fr> In-Reply-To: <20241203-is_constexpr-refactor-v1-0-4e4cbaecc216@wanadoo.fr> To: Linus Torvalds , David Laight , Luc Van Oostenryck , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Yury Norov , Rasmus Villemoes , Kees Cook , "Gustavo A. R. Silva" , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Suzuki K Poulose , Mike Leach , James Clark , Alexander Shishkin , Rikard Falkeborn , Martin Uecker Cc: linux-sparse@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-hardening@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, Vincent Mailhol X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3686; i=mailhol.vincent@wanadoo.fr; h=from:subject:message-id; bh=KhSEJ/z9NSPJazKznaA4eGwJC3/rNJqN3dS4dHFF/N0=; b=owGbwMvMwCV2McXO4Xp97WbG02pJDOm+7485PP/cFjpv4ddvR2VLOPkvvJfXCD3qLZ3Eld3nt LjUeklRRykLgxgXg6yYIsuyck5uhY5C77BDfy1h5rAygQxh4OIUgImY+zH8T7uwUoiP88gRLpWl X/NO/Lygvi6i7yFjyKWdpdGpMdvv/2P4H5bWr3/0ydJ1OX+dF13m2GEVIfQr88mHOomEbc+bzFv kGAE= X-Developer-Key: i=mailhol.vincent@wanadoo.fr; a=openpgp; fpr=ED8F700574E67F20E574E8E2AB5FEB886DBB99C2 X-Endpoint-Received: by B4 Relay for mailhol.vincent@wanadoo.fr/default with auth_id=291 X-Original-From: Vincent Mailhol Reply-To: mailhol.vincent@wanadoo.fr From: Vincent Mailhol Now that all the users of __is_constexpr() have been migrated to is_const() or one of its friends, remove it. The homage to Martin Uecker's genius hack remains in the documentation of __is_const_zero(). Signed-off-by: Vincent Mailhol --- include/linux/compiler.h | 47 ----------------------------------------------- 1 file changed, 47 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 165aa5b9bc484376087a130a1ac1f3edb50c983d..7ba75044828129cf1f81f458ade695786dbf132a 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -252,53 +252,6 @@ static inline void *offset_to_ptr(const int *off) #define __must_be_cstr(p) \ __BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)") -/* - * This returns a constant expression while determining if an argument is - * a constant expression, most importantly without evaluating the argument. - * Glory to Martin Uecker - * - * Details: - * - sizeof() return an integer constant expression, and does not evaluate - * the value of its operand; it only examines the type of its operand. - * - The results of comparing two integer constant expressions is also - * an integer constant expression. - * - The first literal "8" isn't important. It could be any literal value. - * - The second literal "8" is to avoid warnings about unaligned pointers; - * this could otherwise just be "1". - * - (long)(x) is used to avoid warnings about 64-bit types on 32-bit - * architectures. - * - The C Standard defines "null pointer constant", "(void *)0", as - * distinct from other void pointers. - * - If (x) is an integer constant expression, then the "* 0l" resolves - * it into an integer constant expression of value 0. Since it is cast to - * "void *", this makes the second operand a null pointer constant. - * - If (x) is not an integer constant expression, then the second operand - * resolves to a void pointer (but not a null pointer constant: the value - * is not an integer constant 0). - * - The conditional operator's third operand, "(int *)8", is an object - * pointer (to type "int"). - * - The behavior (including the return type) of the conditional operator - * ("operand1 ? operand2 : operand3") depends on the kind of expressions - * given for the second and third operands. This is the central mechanism - * of the macro: - * - When one operand is a null pointer constant (i.e. when x is an integer - * constant expression) and the other is an object pointer (i.e. our - * third operand), the conditional operator returns the type of the - * object pointer operand (i.e. "int *"). Here, within the sizeof(), we - * would then get: - * sizeof(*((int *)(...)) == sizeof(int) == 4 - * - When one operand is a void pointer (i.e. when x is not an integer - * constant expression) and the other is an object pointer (i.e. our - * third operand), the conditional operator returns a "void *" type. - * Here, within the sizeof(), we would then get: - * sizeof(*((void *)(...)) == sizeof(void) == 1 - * - The equality comparison to "sizeof(int)" therefore depends on (x): - * sizeof(int) == sizeof(int) (x) was a constant expression - * sizeof(int) != sizeof(void) (x) was not a constant expression - */ -#define __is_constexpr(x) \ - (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) - /* * Whether 'type' is a signed type or an unsigned type. Supports scalar types, * bool and also pointer types.