From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (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 0903372 for ; Tue, 24 Aug 2021 02:27:34 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id EBDEF613D5; Tue, 24 Aug 2021 02:27:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629772053; bh=NOvJGCvW1HVdaDqhCUnwbbyYfhSHjlfgYPzYKkOiPeI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sVo8kH14HV4YMJUOa/sFGqFKMlYvaRHWnjrvEpgstLxyWfoE1UaForX7zQQFkmpBb Geep8/Zqy1BvWYK0RIAGXu6dEpxEz/49ho/U/ehCqyXPkV6wZ0P4DPwe56qFFYhfkQ aYsarl6rdNXIFELz7+lEKIKNA21PmggLbrFWwmJmPVabnpAtAIlY7OSPmDfZCUb8zV chWdq/uS+UWzJ6Etm0OD8q7/0gzafwogKdqUygQ48muscUfP9iCwxaUwjwVvqH5nOf 7o2M2apdEIejOD0GG69EhgZOchV9AKwNyIzaze5VLDP4UmF1TlrxWdIDnN4UQgb/y8 aR7u/vij+whEg== From: Nathan Chancellor To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Masahiro Yamada Cc: "H. Peter Anvin" , Nick Desaulniers , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, llvm@lists.linux.dev, Nathan Chancellor Subject: [PATCH 2/2] kbuild: Add -Werror=ignored-optimization-argument to CLANG_FLAGS Date: Mon, 23 Aug 2021 19:26:40 -0700 Message-Id: <20210824022640.2170859-3-nathan@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210824022640.2170859-1-nathan@kernel.org> References: <20210824022640.2170859-1-nathan@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Bot: notify Content-Transfer-Encoding: 8bit Similar to commit 589834b3a009 ("kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS"). Clang ignores certain GCC flags that it has not implemented, only emitting a warning: $ echo | clang -fsyntax-only -falign-jumps -x c - clang-14: warning: optimization flag '-falign-jumps' is not supported [-Wignored-optimization-argument] When one of these flags gets added to KBUILD_CFLAGS unconditionally, all subsequent cc-{disable-warning,option} calls fail because -Werror was added to these invocations to turn the above warning and the equivalent -W flag warning into errors. To catch the presence of these flags earlier, turn -Wignored-optimization-argument into an error so that the flags can either be implemented or ignored via cc-option and there are no more weird errors. Signed-off-by: Nathan Chancellor --- scripts/Makefile.clang | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 4cce8fd0779c..2fe38a9fdc11 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -29,7 +29,11 @@ CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) else CLANG_FLAGS += -fintegrated-as endif +# By default, clang only warns on unknown warning or optimization flags +# Make it behave more like gcc by erroring when these flags are encountered +# so they can be implemented or wrapped in cc-option. CLANG_FLAGS += -Werror=unknown-warning-option +CLANG_FLAGS += -Werror=ignored-optimization-argument KBUILD_CFLAGS += $(CLANG_FLAGS) KBUILD_AFLAGS += $(CLANG_FLAGS) export CLANG_FLAGS -- 2.33.0