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=-8.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 AF36AC432C0 for ; Tue, 26 Nov 2019 01:17:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 54C512068F for ; Tue, 26 Nov 2019 01:17:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54C512068F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47MQxM0Zv0zDqVq for ; Tue, 26 Nov 2019 12:17:27 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47MQrd4kH5zDqf0 for ; Tue, 26 Nov 2019 12:13:21 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 47MQrd1PSrz9sPZ; Tue, 26 Nov 2019 12:13:21 +1100 (AEDT) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 465bfd9c44dea6b55962b5788a23ac87a467c923 In-Reply-To: <20191119045712.39633-2-natechancellor@gmail.com> To: Nathan Chancellor , Benjamin Herrenschmidt , Paul Mackerras From: Michael Ellerman Subject: Re: [PATCH v5 1/3] powerpc: Don't add -mabi= flags when building with Clang Message-Id: <47MQrd1PSrz9sPZ@ozlabs.org> Date: Tue, 26 Nov 2019 12:13:21 +1100 (AEDT) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nathan Chancellor , linuxppc-dev@lists.ozlabs.org, Daniel Axtens Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 2019-11-19 at 04:57:10 UTC, Nathan Chancellor wrote: > When building pseries_defconfig, building vdso32 errors out: > > error: unknown target ABI 'elfv1' > > This happens because -m32 in clang changes the target to 32-bit, > which does not allow the ABI to be changed, as the setABI virtual > function is not overridden: > > https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/clang/include/clang/Basic/TargetInfo.h#L1073-L1078 > > https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/clang/lib/Basic/Targets/PPC.h#L327-L365 > > Commit 4dc831aa8813 ("powerpc: Fix compiling a BE kernel with a > powerpc64le toolchain") added these flags to fix building big endian > kernels with a little endian GCC. > > Clang doesn't need -mabi because the target triple controls the default > value. -mlittle-endian and -mbig-endian manipulate the triple into > either powerpc64-* or powerpc64le-*, which properly sets the default > ABI: > > https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/clang/lib/Driver/Driver.cpp#L450-L463 > > https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/llvm/lib/Support/Triple.cpp#L1432-L1516 > > https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/clang/lib/Basic/Targets/PPC.h#L377-L383 > > Adding a debug print out in the PPC64TargetInfo constructor after line > 383 above shows this: > > $ echo | ./clang -E --target=powerpc64-linux -mbig-endian -o /dev/null - > Default ABI: elfv1 > > $ echo | ./clang -E --target=powerpc64-linux -mlittle-endian -o /dev/null - > Default ABI: elfv2 > > $ echo | ./clang -E --target=powerpc64le-linux -mbig-endian -o /dev/null - > Default ABI: elfv1 > > $ echo | ./clang -E --target=powerpc64le-linux -mlittle-endian -o /dev/null - > Default ABI: elfv2 > > Don't specify -mabi when building with clang to avoid the build error > with -m32 and not change any code generation. > > -mcall-aixdesc is not an implemented flag in clang so it can be > safely excluded as well, see commit 238abecde8ad ("powerpc: Don't > use gcc specific options on clang"). > > pseries_defconfig successfully builds after this patch and > powernv_defconfig and ppc44x_defconfig don't regress. > > Link: https://github.com/ClangBuiltLinux/linux/issues/240 > Reviewed-by: Daniel Axtens > Signed-off-by: Nathan Chancellor Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/465bfd9c44dea6b55962b5788a23ac87a467c923 cheers