From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 B74173EEAF4; Fri, 9 Oct 2026 21:45:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791582305; cv=none; b=AZ7F26Jp13+GqTI+bLMOdaJTYkQnjwNMnR6HxMuKvGVQWpg5FPKf6QdQqNLtzzBNkTKjYPGvGRN4vdJs7ERiRtysEfVPfx4kNiBoHJ1EuEorrQYGm0YyDAV9fPe8LsMNdk+RGQIbDAhFIQaowGhBdQ9E3fUqLM5kFGRGt63i544= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791582305; c=relaxed/simple; bh=Mx+Fa3qwtiruTRAvxKYDaJtw/h36DYYsB+OVvBpksoM=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=SthEbBwi6/hdISXuNpqiQxwi1vruQDsbNNkDFUq7B6yhHohJDxrismeyO6iey+7b8ttL98CQW+hgVjZ7owk7ahkRsaaXvWsA3Tszviwo/4+jkxXb44lnOlMLEd+u90kczmWI7EJlZIj8/M1NDQ5t/56t/85EpkVdC+keXKStnXo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kgOFAEQ8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kgOFAEQ8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 630E51F000FF; Fri, 9 Oct 2026 21:45:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791582304; bh=+y+EbJegof4frOO48AQVjywih4C5zhgf/nF5m6CeXSs=; h=Date:From:To:Cc:Subject; b=kgOFAEQ8iV0QomKkcqjDKPJde3Ih42AbStErVhUAS4C0/efh4w4CWATRUgk1SMu6N FfVu3Qq+BOhVDxJgysPfxKwUamojbrUOVNKTtRs8oRbuUqgLsDsYZJt+Adhr9/iFq6 ME0JHml+esVCzDhuVjCdPS1gjI5LdMY/4TLrFx31zz3D/lmqI1b5QF5U5Re6ptCFgd BvRvL/ZHYlvXq/dd1ECthcsnYTVxO+Y0zgNl5Ew3yuakw37VN5k8Z87XkXJN125LnM wrWwR1KDBQprvx1OxyLmnuYqUv/PvYo/vCLFu42gfwaLcpq/Ue9KIjrr1yj3gdtJyh Py58K/RaT2vRA== Date: Fri, 9 Oct 2026 22:45:01 +0100 From: Nathan Chancellor To: Rong Xu , Han Shen Cc: llvm@lists.linux.dev, linux-kbuild@vger.kernel.org Subject: Build breakage from renamed '-split-machine-functions' plugin option Message-ID: <20261009214501.GA905361@ax162> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi Rong and Han, LLVM recently landed a commit renaming the '-split-machine-functions' plugin option to '-function-splitting=all': https://github.com/llvm/llvm-project/commit/3e6acc87c58843e551d6e8e4bf06c26712b04622 This breaks builds with CONFIG_AUTOFDO and CONFIG_LTO_CLANG_THIN with: ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument '-split-machine-functions'. Try: 'ld.lld --help' Obviously, we can handle this rename but I noticed that the combination of '-flto -fsplit-machine-functions' should add the corresponding '-plugin-opt=' since LLVM 15: https://github.com/llvm/llvm-project/commit/72acd042bad35f78232f17addc02196a7af1a6e9 So is this even necessary? Should we just remove KBUILD_LDFLAGS += -plugin-opt=-split-machine-functions from scripts/Makefile.autofdo and rely on '-fsplit-machine-functions' to do the right thing or am I missing something here? -- Cheers, Nathan