From: "Daniel Colascione" <dancol@dancol.org>
To: "Alan Mackenzie" <acm@muc.de>
Cc: Daniel Colascione <dancol@dancol.org>, emacs-devel@gnu.org
Subject: Re: Help please! To track down GC trying to free an already freed object.
Date: Tue, 2 Apr 2019 13:33:02 -0700 [thread overview]
Message-ID: <4a2df4442b4acf2eb2dabd3c2c4227c5.squirrel@dancol.org> (raw)
In-Reply-To: <20190402202412.GA25792@ACM>
> Hello, Daniel.
>
> On Tue, Apr 02, 2019 at 12:09:59 -0700, Daniel Colascione wrote:
>> > Hello, Emacs.
>
>> > I get this problem after a recent merge of master into
>> > /scratch/accurate-warning-pos (my branch where I'm trying to implement
>> > correct source positions in the byte compiler's warning messages).
>> This
>> > was a large merge, including bringing in the portable dumper.
>
>> > Emacs aborts at mark_object L+179 (in alloc.c), because a pseudovector
>> > being freed already has type PVEC_FREE, i.e. has been freed already.
>> > This object is a "symbol with position", a type of pseudovector which
>> > doesn't yet exist outside of this scratch branch.
>
>> Out of curiosity, why do we need a new C-level type here?
>
> It's to help solve a bug in the byte compiler, which up until recently
> was intractable. The byte compiler frequently (?usually) reports
> incorrect line/column numbers in its warning messages. This is due to
> the kludge it uses to keep track of them.
>
> The only current candidate for a fix is for the reader, on a flag being
> bound to non-nil, to return "symbols with position" rather than standard
> symbols. The "position" associated with the symbol is it's textual
> offset from the beginning of the construct in the source file being read.
So if I read symbol foo from file1.el and symbol foo from file2.el, I get
two different symbol-with-location instances, each tagged with a different
source location? Do these symbol objects compare eq to each other?
next prev parent reply other threads:[~2019-04-02 20:33 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-02 11:25 Help please! To track down GC trying to free an already freed object Alan Mackenzie
2019-04-02 15:04 ` Eli Zaretskii
2019-04-02 20:42 ` Alan Mackenzie
2019-04-03 4:43 ` Eli Zaretskii
2019-04-04 18:57 ` Alan Mackenzie
2019-04-02 19:09 ` Daniel Colascione
2019-04-02 19:21 ` Eli Zaretskii
2019-04-02 20:46 ` Alan Mackenzie
2019-04-02 21:03 ` Daniel Colascione
2019-04-03 4:39 ` Eli Zaretskii
2019-04-03 10:01 ` Alan Mackenzie
2019-04-03 10:12 ` Eli Zaretskii
2019-04-03 15:23 ` Paul Eggert
2019-04-02 20:24 ` Alan Mackenzie
2019-04-02 20:33 ` Daniel Colascione [this message]
2019-04-02 21:00 ` Alan Mackenzie
2019-04-05 4:49 ` Alex
2019-04-05 8:26 ` Alan Mackenzie
2019-04-05 17:05 ` Comparing symbol-with-position using eq (was: Help please! To track down GC trying to free an already freed object.) Alex
2019-04-05 18:21 ` Comparing symbol-with-position using eq Alan Mackenzie
2019-04-05 20:18 ` Daniel Colascione
2019-04-05 21:54 ` Alan Mackenzie
2019-04-05 22:50 ` Paul Eggert
2019-04-06 12:23 ` Clément Pit-Claudel
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