From: Marc Glisse <marc.glisse@inria.fr>
To: Ian Lance Taylor <iant@google.com>
Cc: gcc@gcc.gnu.org
Subject: Re: PATCH RFA: Build stages 2 and 3 with C++
Date: Sun, 31 Jul 2011 23:20:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.02.1108010008200.5578@laptop-mg.saclay.inria.fr> (raw)
In-Reply-To: <mcroc0u3ef5.fsf@coign.corp.google.com>
On Fri, 15 Jul 2011, Ian Lance Taylor wrote:
> I would like to propose this patch as a step toward building gcc using a
> C++ compiler. This patch builds stage1 with the C compiler as usual,
> and defaults to building stages 2 and 3 with a C++ compiler built during
> stage 1. This means that the gcc installed and used by most people will
> be built by a C++ compiler. This will ensure that gcc is fully
> buildable with C++, while retaining the ability to bootstrap with only a
> C compiler, not a C++ compiler.
Nice step. Now that gcc can (mostly) build with g++, it would be great if
it could build with a non-gnu compiler. More precisely, with a compiler
that doesn't define __GNUC__. Indeed, the code is quite different in this
case, as can be seen trying to compile gcc with CC='gcc -U__GNUC__' and
CXX='g++ -U__GNUC__' (there are other reasons why this won't work, but at
least it shows some of the same issues I see with sunpro).
To start with, the obstack_free macro casts a pointer to an int -> error.
/data/repos/gcc/trunk/libcpp/directives.c:2048:7: error: cast from Β‘char*Β’
to Β‘intΒ’ loses precision [-fpermissive]
Then, ENUM_BITFIELD(cpp_ttype) is expanded to unsigned int instead of the
enum, and conversions from int to enum require an explicit cast in C++,
giving many errors like:
/data/repos/gcc/trunk/libcpp/charset.c:1615:79: error: invalid conversion
from Β‘unsigned intΒ’ to Β‘cpp_ttypeΒ’ [-fpermissive]
/data/repos/gcc/trunk/libcpp/charset.c:1371:1: error: initializing
argument 5 of Β‘bool cpp_interpret_string(cpp_reader*, const cpp_string*,
size_t, cpp_string*, cpp_ttype)Β’ [-fpermissive]
Do we want to add a cast in almost every place a field declared with
ENUM_BITFIELD is used? That's quite a lot of places, everywhere in gcc...
The alternative would be to store the full enum instead of a bitfield
(just for stage1 so that's not too bad), but some comments in the code
seem to advise against it.
--
Marc Glisse
next prev parent reply other threads:[~2011-07-31 22:56 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-16 6:56 Ian Lance Taylor
2011-07-16 7:05 ` Andrew Pinski
2011-07-16 7:48 ` Ian Lance Taylor
2011-07-16 7:59 ` Basile Starynkevitch
2011-07-17 3:17 ` Ian Lance Taylor
2011-07-16 16:11 ` Diego Novillo
2011-07-16 22:58 ` Ian Lance Taylor
2011-07-17 10:36 ` Richard Guenther
2011-07-17 12:21 ` Eric Botcazou
2011-07-17 16:55 ` Richard Guenther
2011-07-17 17:55 ` Markus Trippelsdorf
2011-07-17 22:37 ` Markus Trippelsdorf
2011-09-04 17:20 ` Thomas Schwinge
2011-07-16 20:40 ` Toon Moene
2011-07-19 21:33 ` Ian Lance Taylor
2011-07-19 22:24 ` Gabriel Dos Reis
2011-07-20 0:46 ` H.J. Lu
2011-07-20 1:15 ` H.J. Lu
2011-07-20 6:28 ` David Edelsohn
2011-07-20 9:34 ` Jonathan Wakely
2011-07-20 11:02 ` Jonathan Wakely
2011-07-20 12:41 ` David Edelsohn
2011-07-20 12:48 ` Richard Guenther
2011-07-20 14:07 ` Diego Novillo
2011-07-20 14:34 ` Ian Lance Taylor
2011-07-20 15:35 ` Jonathan Wakely
2011-07-20 15:06 ` Toon Moene
2011-07-20 15:23 ` Ian Lance Taylor
2011-07-20 15:53 ` David Edelsohn
2011-07-20 15:55 ` Ian Lance Taylor
2011-07-20 20:05 ` David Edelsohn
2011-07-20 20:53 ` Ian Lance Taylor
2011-07-20 21:06 ` Mike Stump
2011-07-21 0:10 ` Ian Lance Taylor
2011-07-21 9:40 ` Basile Starynkevitch
2011-07-21 16:06 ` Ian Lance Taylor
2011-07-21 17:44 ` Jakub Jelinek
2011-07-21 19:40 ` Ian Lance Taylor
2011-07-21 20:12 ` Basile Starynkevitch
2011-07-21 22:38 ` Ian Lance Taylor
2011-07-21 6:57 ` David Edelsohn
2011-07-21 7:25 ` Eric Botcazou
2011-07-21 14:24 ` David Edelsohn
2011-07-20 17:58 ` Thomas Schwinge
2011-07-20 21:41 ` Toon Moene
2011-07-31 23:20 ` Marc Glisse [this message]
2011-08-01 9:14 ` Richard Guenther
2011-08-01 9:53 ` Joseph S. Myers
2011-08-01 9:59 ` Richard Guenther
2011-08-01 10:05 ` Marc Glisse
2011-08-08 17:42 ` Romain Geissler
2011-08-08 18:49 ` Ian Lance Taylor
2011-08-08 19:40 ` Romain Geissler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.2.02.1108010008200.5578@laptop-mg.saclay.inria.fr \
--to=marc.glisse@inria.fr \
--cc=gcc@gcc.gnu.org \
--cc=iant@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).