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From: Daniel Colascione <dancol@dancol.org>
To: "Mattias Engdegård" <mattiase@acm.org>
Cc: 34180@debbugs.gnu.org, Lars Ingebrigtsen <larsi@gnus.org>,
	Paul Eggert <eggert@cs.ucla.edu>,
	Stefan Monnier <monnier@iro.umontreal.ca>
Subject: bug#34180: 27.0.50; argv[0] used incorrectly to find the .pdmp
Date: Tue, 12 Oct 2021 09:24:48 -0700	[thread overview]
Message-ID: <3b65b08e-4f6d-d2cb-6621-7f6e988227de@dancol.org> (raw)
In-Reply-To: <59495BCF-EF2F-4E1F-A466-1CC61CE57893@acm.org>

On 10/12/21 5:27 AM, Mattias Engdegård wrote:
> I don't think Paul meant that we necessarily have to use the embedded dump in-place. It could just as well be the source of a memory copy to its runtime location; everything would then work just like today except that the dump file is embedded into the executable.

Copying the dump on startup will hurt performance --- the dump is meant 
to be used directly from a disk-backed file.

I'm also not entirely clear on how you're planning on avoiding the usual 
problems with executable modification --- relinking the executable can 
change all the locations of the symbols in the binary, and if symbol 
locations change, any previously-generated dump becomes invalid.

Even if on *some* platforms *today* we can replace an embedded dump 
image in an already-built executable without re-linking the thing, 
there's no guarantee that we can continue doing that. (For example --- 
imagine a future platform that signs all binaries during the build 
process.) Modifying binaries is always a platform-specific thing and 
doing it for Emacs risks forward compatibility. Usin a separate dump 
file relies only on public APIs guaranteed to work forever.






  reply	other threads:[~2021-10-12 16:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-23 16:07 bug#34180: 27.0.50; argv[0] used incorrectly to find the .pdmp Stefan Monnier
2019-01-27  3:54 ` Daniel Colascione
2019-01-27 15:23   ` Eli Zaretskii
2021-10-11 14:02     ` Lars Ingebrigtsen
2021-10-11 14:04       ` Lars Ingebrigtsen
2021-10-11 15:10       ` Paul Eggert
2021-10-11 16:05         ` Eli Zaretskii
2021-10-11 20:13         ` Daniel Colascione
2021-10-12  0:51           ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-10-12 10:51           ` Lars Ingebrigtsen
2021-10-12 11:54             ` Philipp Stephani
2021-10-12 11:59               ` Lars Ingebrigtsen
2021-10-12 14:10             ` Eli Zaretskii
2021-10-11 15:54       ` Eli Zaretskii
2021-10-12 10:48         ` Lars Ingebrigtsen
2021-10-11 21:16       ` Richard Stallman
2021-10-12 12:27 ` Mattias Engdegård
2021-10-12 16:24   ` Daniel Colascione [this message]
2021-10-12 16:46     ` Eli Zaretskii
2021-10-12 16:59     ` Mattias Engdegård

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