From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sender4-pp-o91.zoho.com (sender4-pp-o91.zoho.com [136.143.188.91]) by sourceware.org (Postfix) with ESMTPS id F05C2384AB5C; Fri, 26 Apr 2024 13:51:15 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org F05C2384AB5C Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=zoho.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=zoho.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org F05C2384AB5C Authentication-Results: server2.sourceware.org; arc=pass smtp.remote-ip=136.143.188.91 ARC-Seal: i=2; a=rsa-sha256; d=sourceware.org; s=key; t=1714139478; cv=pass; b=IamDXExjvfauSv9felnJSjXHC6GOyVu4tJLsmGiBqvmTPEX/cbMGrGQJAucyl4aYmI79lnHPrC7OSkrWZEuThC6AqTkbJMGQSXKCSmwN4DiZerorh1/X6FyHK/zuUaL9DTHJKcv44HXNHEgsdxjv0manXeNtpJFFet92HUqqzBg= ARC-Message-Signature: i=2; a=rsa-sha256; d=sourceware.org; s=key; t=1714139478; c=relaxed/simple; bh=5OwVX/6glJUiyKMrMRUiaOj43rifnQLQvdIvntT5p+0=; h=DKIM-Signature:Message-ID:Date:MIME-Version:Subject:From:To; b=OkvzdKkbKP2jPjGvkQT8h6+EJVTKwVoYwXh5hwrn1AWJWZMq6tvNVl5Tc5zi+HfAI7HyFgSWVQgC4HgGcwZr3NZcIwodSb2JJBvL+nYNwehFrFvvlJFmoX+ElcOKl4z3XbuGPvy5xahLsDkXpYxhIAtQ+SF9uqvkaiw3OYyGoPs= ARC-Authentication-Results: i=2; server2.sourceware.org ARC-Seal: i=1; a=rsa-sha256; t=1714139471; cv=none; d=zohomail.com; s=zohoarc; b=PSJMX4v3kmmSHKA/3qXF8Y+M8qRKVQvosWQaY8M6j+zTH1+vsO4+gF7T7BYtae/mXMjfPKAUS5slkK7E5HOX6nBjl7Pa5GmsD5QxhPf910M5+lOEhoRFb9yxWP3sko8gprbmwJnKA9Xnnxlpufb2G0H9cb8KRLM6C5lddl8d2mI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1714139471; h=Content-Type:Content-Transfer-Encoding:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To:Cc; bh=46EwkcoUwu7aUTYEygLLJ/oCcaiH954z5Mxr24djaxU=; b=lBm/Z4/vaiqxycS/Zq8v1Wy//uC8MqqKgy8gJroLOxQnF/2TJ1HgbCZDKdGcUjWqF2uQY4i0qPrLgsxGwJWB+vO1WPyonhSDJEkRlSvvjzbXHx/Dg/DiCSEVgIvP4Jn81jFaVC77FWGkBArLwXqfTQE0lDbvOykJ8w6eeOGwM4I= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=zoho.com; spf=pass smtp.mailfrom=bouanto@zoho.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1714139471; s=zm2022; d=zoho.com; i=bouanto@zoho.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:From:From:To:To:References:In-Reply-To:Content-Type:Content-Transfer-Encoding:Feedback-ID:Message-Id:Reply-To:Cc; bh=46EwkcoUwu7aUTYEygLLJ/oCcaiH954z5Mxr24djaxU=; b=CHCueybW1Bmgy5QJ9Bc7RKuNme04toonbUIhDAReHo1QTrnnT0btscNvlMkiERrP tXClWG1UIHOODzAx5JzVWMPmZNN4TC8xQvtNPSpOwM+Aoio/khSh2MPdAqWcPn5F+Cs kIFvNyUV9ySBcxLkwgy5rbwPGnJ8jwAqjOO3t2i8= Received: by mx.zohomail.com with SMTPS id 1714139469997144.34543155002143; Fri, 26 Apr 2024 06:51:09 -0700 (PDT) Message-ID: Date: Fri, 26 Apr 2024 09:51:08 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Frontend access to target features (was Re: [PATCH] libgccjit: Add ability to get CPU features) From: Antoni Boucher To: David Malcolm , jit@gcc.gnu.org, gcc-patches@gcc.gnu.org References: <8b0199d9835f568b7bcde41bf9432c21f604e489.camel@zoho.com> <755705e37731c4fbc3ab7eb1a96d8df0147bb002.camel@redhat.com> <6050c91ae34a2cdaeebd79ada9e2b9ffaf881e21.camel@zoho.com> <997ddb068ca13f755accd03f38141e56c87b84a7.camel@redhat.com> <1f7f229f-5d42-4bb6-9a47-0f3c630bea44@zoho.com> <4d106b99-20b4-466e-9c25-89e00df164f2@zoho.com> Content-Language: en-US, fr In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Feedback-ID: rr08011228b4f98b09aa51b9a3f251c0ed0000fe193f7fde8a65508f10d015bcc326fff7c2e14718eccc2aa408:zu08011226580989f91c8d3016d7c1dfeb00005b25d2992e9a24669409ede4bdde2a229eea8c18a4963cc6:rf0801122626eda9cb0351e3e26a01eca100000ea94b046c9acefc4c550c24f7dd089f523d812f24c36c99:ZohoMail X-ZohoMailClient: External X-Spam-Status: No, score=-3.1 required=5.0 tests=BAYES_00,BODY_8BITS,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,KAM_SHORT,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Now that we have a more general way to check if target-dependent types are supported (see this commit: https://github.com/rust-lang/gcc/commit/1c9a9b2f1fd914cad911467ec1d29f158643c2ce#diff-018089519ab2b14a34313ded0ae1a2f9fcab5f7bcb2fa31f147e1dc757bbdd7aR4016), perhaps we should remove gcc_jit_target_info_supports_128bit_int from this patch, or change it to include the more general way. David, what are your thoughts on this? Le 2024-04-19 à 08 h 34, Antoni Boucher a écrit : > David: Ping. > > Le 2024-04-09 à 09 h 21, Antoni Boucher a écrit : >> David: Ping. >> >> Le 2024-04-01 à 08 h 20, Antoni Boucher a écrit : >>> David: Ping. >>> >>> Le 2024-03-19 à 07 h 03, Arthur Cohen a écrit : >>>> Hi, >>>> >>>> On 3/5/24 16:09, David Malcolm wrote: >>>>> On Thu, 2023-11-09 at 19:33 -0500, Antoni Boucher wrote: >>>>>> Hi. >>>>>> See answers below. >>>>>> >>>>>> On Thu, 2023-11-09 at 18:04 -0500, David Malcolm wrote: >>>>>>> On Thu, 2023-11-09 at 17:27 -0500, Antoni Boucher wrote: >>>>>>>> Hi. >>>>>>>> This patch adds support for getting the CPU features in libgccjit >>>>>>>> (bug >>>>>>>> 112466) >>>>>>>> >>>>>>>> There's a TODO in the test: >>>>>>>> I'm not sure how to test that gcc_jit_target_info_arch returns >>>>>>>> the >>>>>>>> correct value since it is dependant on the CPU. >>>>>>>> Any idea on how to improve this? >>>>>>>> >>>>>>>> Also, I created a CStringHash to be able to have a >>>>>>>> std::unordered_set. Is there any built-in way of >>>>>>>> doing >>>>>>>> this? >>>>>>> >>>>>>> Thanks for the patch. >>>>>>> >>>>>>> Some high-level questions: >>>>>>> >>>>>>> Is this specifically about detecting capabilities of the host that >>>>>>> libgccjit is currently running on? or how the target was configured >>>>>>> when libgccjit was built? >>>>>> >>>>>> I'm less sure about this part. I'll need to do more tests. >>>>>> >>>>>>> >>>>>>> One of the benefits of libgccjit is that, in theory, we support all >>>>>>> of >>>>>>> the targets that GCC already supports.  Does this patch change >>>>>>> that, >>>>>>> or >>>>>>> is this more about giving client code the ability to determine >>>>>>> capabilities of the specific host being compiled for? >>>>>> >>>>>> This should not change that. If it does, this is a bug. >>>>>> >>>>>>> >>>>>>> I'm nervous about having per-target jit code.  Presumably there's a >>>>>>> reason that we can't reuse existing target logic here - can you >>>>>>> please >>>>>>> describe what the problem is.  I see that the ChangeLog has: >>>>>>> >>>>>>>>          * config/i386/i386-jit.cc: New file. >>>>>>> >>>>>>> where i386-jit.cc has almost 200 lines of nontrivial code.  Where >>>>>>> did >>>>>>> this come from?  Did you base it on existing code in our source >>>>>>> tree, >>>>>>> making modifications to fit the new internal API, or did you write >>>>>>> it >>>>>>> from scratch?  In either case, how onerous would this be for other >>>>>>> targets? >>>>>> >>>>>> This was mostly copied from the same code done for the Rust and D >>>>>> frontends. >>>>>> See this commit and the following: >>>>>> https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b1c06fd9723453dd2b2ec306684cb806dc2b4fbb >>>>>> The equivalent to i386-jit.cc is there: >>>>>> https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=22e3557e2d52f129f2bbfdc98688b945dba28dc9 >>>>> >>>>> [CCing Iain and Arthur re those patches; for reference, the patch >>>>> being >>>>> discussed is attached to : >>>>> https://gcc.gnu.org/pipermail/jit/2024q1/001792.html ] >>>>> >>>>> One of my concerns about this patch is that we seem to be gaining code >>>>> that's per-(frontend x config) which seems to be copied and pasted >>>>> with >>>>> a search and replace, which could lead to an M*N explosion. >>>> >>>> I think this is definitely already the case, and it would be worth >>>> investigating if C/C++/Rust/jit can reuse a similar set of target >>>> files, or how to factor them together. I imagine that all of these >>>> components share similar needs for the targets they support. >>>> >>>>> >>>>> Is there any real difference between the per-config code for the >>>>> different frontends, or should there be a general "enumerate all >>>>> features of the target" hook that's independent of the frontend? (but >>>>> perhaps calls into it). >>>>> >>>>> Am I right in thinking that (rustc with default LLVM backend) has some >>>>> set of feature strings that both (rustc with rustc_codegen_gcc) and >>>>> gccrs are trying to emulate?  If so, is it presumably a goal that >>>>> libgccjit gives identical results to gccrs?  If so, would it be crazy >>>>> for libgccjit to consume e.g. config/i386/i386-rust.cc ? >>>> >>>> I think this would definitely make sense, and it could probably be >>>> extended to other frontends. For the time being I think it makes >>>> sense to try it out for gccrs and jit. But finding a fitting name >>>> will be hard :) >>>> >>>> Best, >>>> >>>> Arthur >>>> >>>>> >>>>> Dave >>>>> >>>>>> >>>>>>> >>>>>>> I'm not at expert at target hooks (or at the i386 backend), so if >>>>>>> we >>>>>>> do >>>>>>> go with this approach I'd want someone else to review those parts >>>>>>> of >>>>>>> the patch. >>>>>>> >>>>>>> Have you verified that GCC builds with this patch with jit *not* >>>>>>> enabled in the enabled languages? >>>>>> >>>>>> I will do. >>>>>> >>>>>>> >>>>>>> [...snip...] >>>>>>> >>>>>>> A nitpick: >>>>>>> >>>>>>>> +.. function:: const char * \ >>>>>>>> +              gcc_jit_target_info_arch (gcc_jit_target_info >>>>>>>> *info) >>>>>>>> + >>>>>>>> +   Get the architecture of the currently running CPU. >>>>>>> >>>>>>> What does this string look like? >>>>>>> How long does the pointer remain valid? >>>>>> >>>>>> It's the march string, like "znver2", for instance. >>>>>> It remains valid until we free the gcc_jit_target_info object. >>>>>> >>>>>>> >>>>>>> Thanks again; hope the above makes sense >>>>>>> Dave >>>>>>> >>>>>> >>>>>