From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76332C433E0 for ; Wed, 24 Jun 2020 21:30:50 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4274E2081A for ; Wed, 24 Jun 2020 21:30:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Sjm7Enuj"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="QSb2yx30" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4274E2081A Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=3MbPXjlr6lFkbpQo+f6snABMY42twr/lN2DZ58gyiag=; b=Sjm7EnujGdd9MlGHQIfThpYCY afu8kJKpFErXdzCmAPCt3aR7tVH4Vc4IWZU28SafEZOftrWmgjocQ1Lx+9cyE9wi6yepGPeuYq5Sx 3Ons1rEt0mR4RFNlGil3rggLf7lGPUhM30QVAIRjj3ek0BeHS/S40RxQpux7fPPXEA+uYZchasr8q +lGj9j8xdq/WjFsMOFbzDSNlbkW+YBtUrx7ZiH4HUkcgL1fkn80CWMsYk9I9P9AFunJFS28894Tdt HKdJpa+5yR6aQHCIiKfshacDy/qqF0WmQ2H3JXNhp8WGO8KWAAzS4efDQxJvGz0zapM+5DusCBqn1 0nJrengzg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1joCxH-0007Rm-Ik; Wed, 24 Jun 2020 21:29:15 +0000 Received: from mail-pg1-x543.google.com ([2607:f8b0:4864:20::543]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1joCxE-0007Pq-QY for linux-arm-kernel@lists.infradead.org; Wed, 24 Jun 2020 21:29:13 +0000 Received: by mail-pg1-x543.google.com with SMTP id r18so2071676pgk.11 for ; Wed, 24 Jun 2020 14:29:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=8S7wdQVFSvGinNDpzeGeM5bOvAIHO3+dn7qtS4xKvV8=; b=QSb2yx30HozPwbE3cmDUoYnn/m54tkj1kAjJCdgJUPE9p9hcmMPBKaVPQ8nq6Bc1WJ qB9goQOthKh59QOfHEOB0pjBNCmP4PYV/LKAx2CJEjeYgcYLuigmtDK1rd0z3GBirbjf QT7+7vbSd+q2ZOzjXvTocpYNfGsOGa/P0watDoU+3ObHezue05cXmufnhVEm5Q3ZZmTa XCjrJbaX5IO0+0GeI80gfIvjmkaMIwYTVrZh2tjnwzLuU1tncROVGCLiilpUzqVPfzKM RIHYMVRhw56vrkubCQ6vuKEMInx200lTXE2eT3cyIagXjOxlrxuHoW9NFhenw6ZcgEPv QI4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=8S7wdQVFSvGinNDpzeGeM5bOvAIHO3+dn7qtS4xKvV8=; b=FplJ/DeFykcz3lrukqdM+VKvD+RkMPELRfy7bQ/alK4UshaTePF671HFpMj4oNaHXl WRu7vJ1gNGoZ0CHzkWWNeUdyJadBqNew5f2RYwDb3FTycwweyuy/QwoJOtBNvFouxmd9 XdROsKDJtOaRdklIslJA1ZYFWgzNeMziGQktvd51uULUA4BOjE5OqBXRUsSIo12ruSY6 +MvmWYMaz2t6wKObMzXhpKPW0HxXL9Vp6vSfNW+Rtm5GwFmZlnlf3V5yJRuwysyNsUzc TrnBJWSgZvfTvT0U9wQgWXBNiyQhDDUY4PQC7aXnn6m1L2tAH+SRQ+vK2v+kDHRRokSS QwmA== X-Gm-Message-State: AOAM531s4P9vA1HljX+omC9XcsiKIoYCR96KKHcOhyhh+PXcI4qAIjn+ psnhnZeZG8XQfReHYPysNp3uiQ== X-Google-Smtp-Source: ABdhPJzNztQf4xK5/Zlp8kovh17ym7/QBwLnR6UiKFeUru/SjadRA2bRjfkD85Hht24sZeCqpm8n5Q== X-Received: by 2002:a63:79c2:: with SMTP id u185mr6299836pgc.84.1593034148817; Wed, 24 Jun 2020 14:29:08 -0700 (PDT) Received: from google.com ([2620:15c:201:2:ce90:ab18:83b0:619]) by smtp.gmail.com with ESMTPSA id q1sm22211040pfk.132.2020.06.24.14.29.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jun 2020 14:29:08 -0700 (PDT) Date: Wed, 24 Jun 2020 14:29:02 -0700 From: Sami Tolvanen To: Nick Desaulniers Subject: Re: [PATCH 02/22] kbuild: add support for Clang LTO Message-ID: <20200624212902.GA26253@google.com> References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-3-samitolvanen@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch , "maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)" , Kees Cook , "Paul E. McKenney" , Kernel Hardening , Greg Kroah-Hartman , Masahiro Yamada , Linux Kbuild mailing list , LKML , clang-built-linux , linux-pci@vger.kernel.org, Will Deacon , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jun 24, 2020 at 01:53:52PM -0700, Nick Desaulniers wrote: > On Wed, Jun 24, 2020 at 1:32 PM Sami Tolvanen wrote: > > > > diff --git a/Makefile b/Makefile > > index ac2c61c37a73..0c7fe6fb2143 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -886,6 +886,22 @@ KBUILD_CFLAGS += $(CC_FLAGS_SCS) > > export CC_FLAGS_SCS > > endif > > > > +ifdef CONFIG_LTO_CLANG > > +ifdef CONFIG_THINLTO > > +CC_FLAGS_LTO_CLANG := -flto=thin $(call cc-option, -fsplit-lto-unit) > > The kconfig change gates this on clang-11; do we still need the > cc-option check here, or can we hardcode the use of -fsplit-lto-unit? > Playing with the flag in godbolt, it looks like clang-8 had support > for this flag. True, we don't need cc-option here anymore. I'll remove it, thanks. > > +KBUILD_LDFLAGS += --thinlto-cache-dir=.thinlto-cache > > It might be nice to have `make distclean` or even `make clean` scrub > the .thinlto-cache? Also, I verified that the `.gitignore` rule for > `.*` properly ignores this dir. Sure, distclean sounds appropriate to me. Sami _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel