From: Jeffrey A Law <law@cygnus.com>
To: Neil Booth <NeilB@earthling.net>
Cc: Byron Stanoszek <gandalf@winds.org>,
geoffk@cygnus.com, gcc@gcc.gnu.org, gcc-patches@gcc.gnu.org,
jakub@redhat.com
Subject: Re: warning: pasting would not give a valid preprocessing token
Date: Thu, 14 Sep 2000 16:08:00 -0000 [thread overview]
Message-ID: <7437.968972879@upchuck> (raw)
In-Reply-To: <20000914235302.A9969@daikokuya.demon.co.uk>
In message < 20000914235302.A9969@daikokuya.demon.co.uk >you write:
> [There's no point cc-ing Zack; his mail address is no more]
>
> Byron,
>
> I hope this fixes it for you. I'm bootstrapping now, and will then
> run the testsuite.
>
> This area is a bit ugly and in bad need of a cleanup. I need to
> extract more flexibility from the lexer first, though. The problem
> was in the way we handle macro arguments: each argument is a list of
> pointers to the tokens making up the argument. These tend to point to
> the original tokens (in this case, the comma in the macro definition
> in the hash table). That token has a PASTE_LEFT flag to say it's on
> the left hand side of a ##. The problem is that after processing the
> paste, and correctly not emitting a warning about invalid pastes, we
> maintained a pointer to the same comma for the nested macro
> replacements (since it is part of an argument itself). Unforunately,
> of course, that comma still has its paste flag set, so the paste
> mechanism gets re-invoked in later unintended places; hence the
> (repeated) warnings.
>
> This is a nice testcase for quite a deep nested macro bug. I
> simplified your case to the one below, which I'll commit along with
> the fix. If you have a chance, please give it a whirl.
>
> It also fixes a bug in ON_REST_ARG - the macro was testing the flags
> of the wrong thing (easy to do since #defines are typeless). Any
> relief the original fix brought might therefore be undone; I'd be
> interested in knowing if the warnings it "cured" come back with this
> patch.
>
> OK to commit?
>
> Neil.
>
> * cpplex.c (ON_REST_ARG): Correct the test.
> (maybe_paste_with_next): Duplicate a token that fail pasting,
> and clear its PASTE_LEFT flag, so that nested pasting attempts
> do not occur.
> * gcc.dg/cpp/paste10.c: Testcase.
Assuming the bootstrap & test passes, this is fine to install.
jeff
next prev parent reply other threads:[~2000-09-14 16:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20000914185040.A12722@daikokuya.demon.co.uk>
[not found] ` <Pine.LNX.4.21.0009141510140.21092-201000@winds.org>
2000-09-14 15:53 ` Neil Booth
2000-09-14 16:02 ` Neil Booth
2000-09-14 16:08 ` Jeffrey A Law [this message]
2000-09-15 16:53 ` Byron Stanoszek
2000-08-11 20:41 Byron Stanoszek
2000-08-11 20:46 ` Geoff Keating
2000-08-11 20:58 ` Byron Stanoszek
2000-08-11 23:31 ` Zack Weinberg
2000-08-12 8:19 ` Byron Stanoszek
2000-09-06 19:18 ` Zack Weinberg
2000-09-07 12:04 ` Byron Stanoszek
2000-09-11 21:44 ` Zack Weinberg
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