From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 48199 invoked by alias); 27 Aug 2019 14:58:06 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 48182 invoked by uid 89); 27 Aug 2019 14:58:06 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-6.4 required=5.0 tests=AWL,BAYES_00,KAM_SHORT,SPF_HELO_PASS autolearn=ham version=3.3.1 spammy=vacation X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 27 Aug 2019 14:58:04 +0000 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F3981106E96B; Tue, 27 Aug 2019 14:58:02 +0000 (UTC) Received: from ovpn-117-125.phx2.redhat.com (ovpn-117-125.phx2.redhat.com [10.3.117.125]) by smtp.corp.redhat.com (Postfix) with ESMTP id 67DCB60F88; Tue, 27 Aug 2019 14:58:02 +0000 (UTC) Message-ID: <1566917881.3379.24.camel@redhat.com> Subject: Re: Rust front-end From: David Malcolm To: Mateus Carmo Martins de Freitas Barbosa , gcc@gcc.gnu.org Cc: Philip Herron Date: Tue, 27 Aug 2019 14:58:00 -0000 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2019-08/txt/msg00220.txt.bz2 On Fri, 2019-08-23 at 11:10 -0300, Mateus Carmo Martins de Freitas Barbosa wrote: > I'm interested in working on the Rust front-end for GCC. > > So far I've cloned the repository git> > and tried to compile it as described in tFrontEnd>. > I've compiled it outside of the gcc directory tree with > > $ ../gccrs/configure --prefix=/opt/gccrs --enable-languages=rust > --disable-multilib --disable-bootstrap > $ make > > > But this produces some linking errors for functions that were called > but never defined: > > > /usr/bin/ld: rust/rust-lang.o: in function > `rust_langhook_handle_option(unsigned long, char const*, long, int, > unsigned int, cl_option_handlers const*)': > /home/baal/gccrs-build/gcc/../../gccrs/gcc/rust/rust-lang.c:185: > undefined reference to `rust_add_search_path(char const*)' > /usr/bin/ld: /home/baal/gccrs-build/gcc/../../gccrs/gcc/rust/rust- > lang.c:213: > undefined reference to `rust_add_search_path(char const*)' > /usr/bin/ld: /home/baal/gccrs-build/gcc/../../gccrs/gcc/rust/rust- > lang.c:217: > undefined reference to `rust_add_search_path(char const*)' > /usr/bin/ld: rust/rust-lang.o: in function > `rust_langhook_post_options': > /home/baal/gccrs-build/gcc/../../gccrs/gcc/rust/rust-lang.c:245: > undefined reference to `rust_add_search_path(char const*)' > /usr/bin/ld: rust/rust-lang.o: in function > `rust_langhook_parse_file()': > /home/baal/gccrs-build/gcc/../../gccrs/gcc/rust/rust-lang.c:282: > undefined reference to `rust_parse_input_files(char const**, unsigned > int, bool)' > /usr/bin/ld: rust/rust-lang.o:/home/baal/gccrs-build/gcc/./gtype- > rust.h:24: > undefined reference to `rust_non_zero_struct' > collect2: error: ld returned 1 exit status > make[2]: *** [../../gccrs/gcc/rust/Make-lang.in:61: rust1] Error 1 > make[2]: Leaving directory '/home/baal/gccrs-build/gcc' > make[1]: *** [Makefile:4319: all-gcc] Error 2 > > > It's doesn't really help that the latest commit message > (3b1e76d808b9725e6ef439ae534011370e65fb85) says simply "x" and the > previous one, only "more". Anyhow, I'm left with those questions: > > - Considering I'm new to gcc development, what should I read before > getting into this? > - Is there any developer in particular I should talk to? As far as I can tell, this is a side-project by one gcc developer ("redbrain" aka Philip Herron), who appears to only work on it intermittently. It may not be the best start for someone new to gcc development. I've CCed him on this email (hi Philip!) as I suspect he hasn't seen this thread (or might be on vacation). > - Is there anything else I need to know before getting started? FWIW, I'm not convinced that a rust frontend to gcc is the best approach - Rust has some complicated semantic-checking rules that must be implemented by a compiler (the "borrow checker"). Hopefully that code is available via a library. One approach would be something like how the GCC Go frontend works, which uses a library shared with the other Go compiler implementation to parse the code, and turn it into GCC's IR, which then goes through GCC's optimizer and backend. Another approach would be to build a gcc-based backend to the existing rust compiler, as an alternative to its LLVM-based backend, rather than a rust frontend to gcc. libgccjit (despite its name) has the ability to generate ahead-of-time code (e.g. .o files), and has rust bindings, and thus could be embedded inside rustc - in theory, at least. I'm the maintainer of libgccjit. See this discussion: https://users.rust-lang.org/t/rust-front-end-to-gcc/11601 Although I'm a fan of Rust, I'm deep in the middle of another gcc- related project, and I don't have cycles to spare to work on this (beyond answering libgccjit questions). Hope this is helpful and constructive Dave