From owner-dev-commits-src-main@freebsd.org Tue May 25 18:15:04 2021 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 14701651945; Tue, 25 May 2021 18:15:04 +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 "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4FqMgW3hWhz3vFR; Tue, 25 May 2021 18:15:03 +0000 (UTC) (envelope-from git@FreeBSD.org) 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 454CB224E9; Tue, 25 May 2021 18:15:03 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 14PIF3HW043888; Tue, 25 May 2021 18:15:03 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 14PIF3ck043887; Tue, 25 May 2021 18:15:03 GMT (envelope-from git) Date: Tue, 25 May 2021 18:15:03 GMT Message-Id: <202105251815.14PIF3ck043887@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: "Bjoern A. Zeeb" Subject: git: 1082490cd867 - main - LinuxKPI: change BUILD_BUG_ON() MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: bz X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 1082490cd867a4d443862523c37ce947735342d0 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 May 2021 18:15:04 -0000 The branch main has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=1082490cd867a4d443862523c37ce947735342d0 commit 1082490cd867a4d443862523c37ce947735342d0 Author: Bjoern A. Zeeb AuthorDate: 2021-05-24 18:26:41 +0000 Commit: Bjoern A. Zeeb CommitDate: 2021-05-25 18:01:47 +0000 LinuxKPI: change BUILD_BUG_ON() BUILD_BUG_ON() can be used inside functions where the definition to CTASSERT() (_Static_assert()) seems to not work. Go back to an old-style CTASSERT() implementation but also add a variable dclaration to avoid "unsued typedef" errors and dummy-use the variable to avoid "unusued variable" errors. Given it is all self-contained in a block and not used outside this should be optimised away. Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Reviewed by: hselasky Differential Revision: https://reviews.freebsd.org/D30431 --- sys/compat/linuxkpi/common/include/linux/kernel.h | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/sys/compat/linuxkpi/common/include/linux/kernel.h b/sys/compat/linuxkpi/common/include/linux/kernel.h index b30fa8ba5729..807138334fdd 100644 --- a/sys/compat/linuxkpi/common/include/linux/kernel.h +++ b/sys/compat/linuxkpi/common/include/linux/kernel.h @@ -89,8 +89,23 @@ #define S64_C(x) x ## LL #define U64_C(x) x ## ULL +/* + * BUILD_BUG_ON() can happen inside functions where _Static_assert() does not + * seem to work. Use old-schoold-ish CTASSERT from before commit + * a3085588a88fa58eb5b1eaae471999e1995a29cf but also make sure we do not + * end up with an unused typedef or variable. The compiler should optimise + * it away entirely. + */ +#define _O_CTASSERT(x) _O__CTASSERT(x, __LINE__) +#define _O__CTASSERT(x, y) _O___CTASSERT(x, y) +#define _O___CTASSERT(x, y) while (0) { \ + typedef char __assert_line_ ## y[(x) ? 1 : -1]; \ + __assert_line_ ## y _x; \ + _x[0] = '\0'; \ +} + #define BUILD_BUG() do { CTASSERT(0); } while (0) -#define BUILD_BUG_ON(x) CTASSERT(!(x)) +#define BUILD_BUG_ON(x) _O_CTASSERT(!(x)) #define BUILD_BUG_ON_MSG(x, msg) BUILD_BUG_ON(x) #define BUILD_BUG_ON_NOT_POWER_OF_2(x) BUILD_BUG_ON(!powerof2(x)) #define BUILD_BUG_ON_INVALID(expr) while (0) { (void)(expr); }