From patchwork Mon Aug 2 23:43:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 12414949 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=-31.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 4CEA1C4338F for ; Mon, 2 Aug 2021 23:43:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 228F960EE3 for ; Mon, 2 Aug 2021 23:43:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232400AbhHBXnZ (ORCPT ); Mon, 2 Aug 2021 19:43:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232208AbhHBXnY (ORCPT ); Mon, 2 Aug 2021 19:43:24 -0400 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95911C0613D5 for ; Mon, 2 Aug 2021 16:43:13 -0700 (PDT) Received: by mail-qv1-xf4a.google.com with SMTP id hf7-20020a0562140e87b02902dc988b8675so14200583qvb.3 for ; Mon, 02 Aug 2021 16:43:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=yy9pyQojvK7Hdmo6VGo2Lui7HtlFWMn7Zh2eGYLAN30=; b=UH3CUy9t8ryrDG4F3pv3TetQOMIQtKV6Y2LYsFhy+ponF7FuzwIOeDtuKfPCeNRPz7 qHv8bicgNi2Ms3bIMqrwpY0Md+goVKT37gdnPhhc2+yX4vG/W+X5cyUIn/dkmk2cLyF0 MRdcgQAGixOudrNX42SWMNzXoN/NtEIZjLBCDQl4+oKI8Pl+WlHKMJloWVrWpXB5Vm7P Ssr1i3ElcLtqhCrLJGNmyjpeEgyd+YFIKF+sgrp6IBqZg7VKnHjNmygADAV0uwUssdse Gi6DioUPgJIJ+D58vtaUZ8bRm/0K+LhPuz3XJtLMDhzu/CXC+QDLi2/WPpwFQ0LZjaMX rd9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=yy9pyQojvK7Hdmo6VGo2Lui7HtlFWMn7Zh2eGYLAN30=; b=ae7CkR41KKKlMuxKLYsne32LjPk7cI3XngfDuOta2WS0MwGePUFjJs/sMq8waf9Smd /8SQMqNFQ089tMEcN5kH1o2mr8Av7trFjhuKluzOf1uIn3WtSKhC40JP8pBH2f5+fuX/ yVgdiywzRFmZdwv1BbchEqTl1hmis8j8NoJomaBWvsYFm7lX7wknQtyh33DY8OhLXCn3 Ma6Qg9pUlJKkXb932wKO+sgE0d6GMP5O8gxgtPWuRjIvmFvd9cV1jXw27XZ5lkmKWX43 OVs3r0btoJU/VNbnst5ZOmEJrRc++D1vUJ1QwAhfub2jJ8EIdvTp381Q3eGs3fJeGLlw vVzA== X-Gm-Message-State: AOAM533knukBJJlFhDdd06Sta93p6D2w1jRZ26cx61Mn/flWguCwMRVh 6NG92NAKH/2bRtsImsLqLi+NIAHQP54HxZyYMDk= X-Google-Smtp-Source: ABdhPJxv56UYXw0HdwPKZZQFp3/zRO8zP8qIjavfTRIKYqCH5596UCuGHqajKqMv8WCVM5UAz4HoFd32fzVH1fyJqgg= X-Received: from ndesaulniers1.mtv.corp.google.com ([2620:15c:211:202:3db0:42c:8665:a4ae]) (user=ndesaulniers job=sendgmr) by 2002:a0c:b44b:: with SMTP id e11mr18946709qvf.38.1627947792748; Mon, 02 Aug 2021 16:43:12 -0700 (PDT) Date: Mon, 2 Aug 2021 16:43:03 -0700 Message-Id: <20210802234304.3519577-1-ndesaulniers@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.32.0.554.ge1b32706d8-goog Subject: [PATCH] scripts/Makefile.clang: default to LLVM_IAS=1 From: Nick Desaulniers To: Masahiro Yamada , Nathan Chancellor Cc: Khem Raj , Nick Desaulniers , Michal Marek , Jonathan Corbet , Paul Walmsley , Palmer Dabbelt , Albert Ou , clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org LLVM_IAS=1 controls enabling clang's integrated assembler via -integrated-as. This was an explicit opt in until we could enable assembler support in Clang for more architecures. Now we have support and CI coverage of LLVM_IAS=1 for all architecures except a few more bugs affecting s390 and powerpc. This commit flips the default from opt in via LLVM_IAS=1 to opt out via LLVM_IAS=0. CI systems or developers that were previously doing builds with CC=clang or LLVM=1 without explicitly setting LLVM_IAS must now explicitly opt out via LLVM_IAS=0, otherwise they will be implicitly opted-in. This finally shortens the command line invocation when cross compiling with LLVM to simply: $ make ARCH=arm64 LLVM=1 Link: https://github.com/ClangBuiltLinux/linux/issues/1434 Signed-off-by: Nick Desaulniers --- Note: base is: https://lore.kernel.org/lkml/20210802183910.1802120-1-ndesaulniers@google.com/ Documentation/kbuild/llvm.rst | 14 ++++++++------ Makefile | 2 +- arch/riscv/Makefile | 2 +- scripts/Makefile.clang | 6 +++--- 4 files changed, 13 insertions(+), 11 deletions(-) base-commit: d7a86429dbc691bf540688fcc8542cc20246a85b prerequisite-patch-id: 0d3072ecb5fd06ff6fd6ea81fe601f6c54c23910 prerequisite-patch-id: 2654829756eb8a094a0ffad1679caa75a4d86619 prerequisite-patch-id: a51e7885ca2376d008bbf146a5589da247806f7b diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst index f8a360958f4c..16712fab4d3a 100644 --- a/Documentation/kbuild/llvm.rst +++ b/Documentation/kbuild/llvm.rst @@ -60,17 +60,14 @@ They can be enabled individually. The full list of the parameters: :: OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump READELF=llvm-readelf \ HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar HOSTLD=ld.lld -Currently, the integrated assembler is disabled by default. You can pass -``LLVM_IAS=1`` to enable it. +Currently, the integrated assembler is enabled by default. You can pass +``LLVM_IAS=0`` to disable it. Omitting CROSS_COMPILE ---------------------- As explained above, ``CROSS_COMPILE`` is used to set ``--target=``. -Unless ``LLVM_IAS=1`` is specified, ``CROSS_COMPILE`` is also used to derive -``--prefix=`` to search for the GNU assembler and linker. - If ``CROSS_COMPILE`` is not specified, the ``--target=`` is inferred from ``ARCH``. @@ -78,7 +75,12 @@ That means if you use only LLVM tools, ``CROSS_COMPILE`` becomes unnecessary. For example, to cross-compile the arm64 kernel:: - make ARCH=arm64 LLVM=1 LLVM_IAS=1 + make ARCH=arm64 LLVM=1 + +If ``LLVM_IAS=0`` is specified, ``CROSS_COMPILE`` is also used to derive +``--prefix=`` to search for the GNU assembler and linker. :: + + make ARCH=arm64 LLVM=1 LLVM_IAS=0 CROSS_COMPILE=aarch64-linux-gnu- Supported Architectures ----------------------- diff --git a/Makefile b/Makefile index 444558e62cbc..b24b48c9ebb7 100644 --- a/Makefile +++ b/Makefile @@ -845,7 +845,7 @@ else DEBUG_CFLAGS += -g endif -ifneq ($(LLVM_IAS),1) +ifeq ($(LLVM_IAS),0) KBUILD_AFLAGS += -Wa,-gdwarf-2 endif diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index bc74afdbf31e..807f7c94bc6f 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -41,7 +41,7 @@ endif ifeq ($(CONFIG_LD_IS_LLD),y) KBUILD_CFLAGS += -mno-relax KBUILD_AFLAGS += -mno-relax -ifneq ($(LLVM_IAS),1) +ifeq ($(LLVM_IAS),0) KBUILD_CFLAGS += -Wa,-mno-relax KBUILD_AFLAGS += -Wa,-mno-relax endif diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 1f4e3eb70f88..3ae63bd35582 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -22,12 +22,12 @@ else CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) endif # CROSS_COMPILE -ifeq ($(LLVM_IAS),1) -CLANG_FLAGS += -integrated-as -else +ifeq ($(LLVM_IAS),0) CLANG_FLAGS += -no-integrated-as GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) +else +CLANG_FLAGS += -integrated-as endif CLANG_FLAGS += -Werror=unknown-warning-option KBUILD_CFLAGS += $(CLANG_FLAGS)