From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 C36A46E589 for ; Tue, 5 Dec 2023 21:38:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="YnhA+Lw6" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=HKW4QFdw1SLSy+SkuqSHdm3s7yV1a+qPMBI8CTnpIIQ=; b=YnhA+Lw601956o/BXGvoJwVs6b HJ/ruVA7o7YK8GsFiaU8pesx1TY1HZe1YgvI/ZNQpHpMBDU1HidBuw3Kug5y5Z8Oys6bgmCguEvDr MhBtL7J+wjd/TtYdnXZt1YFqpBQbN0xHEt0ohsYHTviT3X8TcdUj6b6B7VGrkd4Btgr7vUCxP0fLQ WI97i5i8K2w8RdHp73Gq3qQb8+t2H73w2SbEWYijKjHabtCMOokySCrhY0UI/i9cvJHpuI4DzyrZN TbR3KybOl1fMP5diqdjKNvn7tcSi9twOa7taauWBAPPv6yKEQp9/3QvK2reorfJe4Hhfq65+pD7JO UTb3UfQw==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1rAd7H-007TNt-26; Tue, 05 Dec 2023 21:38:07 +0000 Date: Tue, 5 Dec 2023 21:38:07 +0000 From: Al Viro To: tanzirh@google.com Cc: Kees Cook , Andy Shevchenko , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, Nick DeSaulniers , Andrew Morton , llvm@lists.linux.dev Subject: Re: [PATCH] lib/string: shrink lib/string.i via IWYU Message-ID: <20231205213807.GE1674809@ZenIV> References: <20231205-libstringheader-v1-1-7f9c573053a7@gmail.com> 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 In-Reply-To: <20231205-libstringheader-v1-1-7f9c573053a7@gmail.com> Sender: Al Viro On Tue, Dec 05, 2023 at 08:58:53PM +0000, tanzirh@google.com wrote: > This diff uses an open source tool include-what-you-use (IWYU) to modify > the include list changing indirect includes to direct includes. How does it account for arch- and config-dependent indirect includes? In particular, on sh this patch breaks, since there word-at-a-time.h does not contain an include of kernel.h, even though it uses REPEAT_BYTE. This is a very simple case (they really ought to include kernel.h, same as all other instances of word-at-a-time.h), but I would expect arseloads of more subtle breakage in anything less trivial. And I'm not at all sure that there's no config-dependent breakage as well - this had been caught by quick make allmodconfig + make lib/string.o on a bunch of architectures; the graph of indirects includes (as well as the set of symbols needed for given header) is very much config-dependent. > IWYU is implemented using the IWYUScripts github repository which is a tool that is > currently undergoing development. These changes seek to improve build times. > > This change to lib/string.c resulted in a preprocessed size of > lib/string.i from 26371 lines to 5232 lines (-80%). It also breeds includes of asm/*.h, by the look of the output, which is not a good thing in general ;-/ E.g. #include *anywhere* outside of linux/uaccess.h is a bad idea. > If there are any problems with the output of the tool please raise an > issue on the github. Sorry, no. Your tool, your workflow, of course, but I don't do github issues. You are welcome to the contents of this reply, but I'm not using browser-based UI without very strong reasons; this one isn't.