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From: "Rafael Espíndola" <rafael.espindola@gmail.com>
To: Sriraman Tallam <tmsriram@google.com>
Cc: gnu-gabi@sourceware.org, binutils <binutils@sourceware.org>,
	 Xinliang David Li <davidxl@google.com>,
	Cary Coutant <ccoutant@gmail.com>,
	 Sterling Augustine <saugustine@google.com>,
	Paul Pluzhnikov <ppluzhnikov@google.com>,
	 Ian Lance Taylor <iant@google.com>,
	"H.J. Lu" <hjl.tools@gmail.com>,
	 Rahul Chaudhry <rahulchaudhry@google.com>,
	Luis Lozano <llozano@google.com>,
	 Peter Collingbourne <pcc@google.com>,
	Rui Ueyama <ruiu@google.com>
Subject: Re: Reducing code size of Position Independent Executables (PIE) by shrinking the size of dynamic relocations section
Date: Sun, 01 Jan 2017 00:00:00 -0000	[thread overview]
Message-ID: <CAG3jReKcwAOzm9UYmUUHU_peNRoK3u=sLd5FqKaca30zD29bew@mail.gmail.com> (raw)
In-Reply-To: <CAAs8HmyKSjqo2GKD0TQy8R80sVcXB3mNORMpXZ_a6sDdmWQOdg@mail.gmail.com>

On 25 April 2017 at 13:12, Sriraman Tallam <tmsriram@google.com> wrote:
> We identified a problem with PIE executables, more than 5% code size
> bloat compared to non-PIE and we have a few proposals to reduce the
> bloat.  Please take a look and let us know what you think.

Just a bit of terminology, it is not code, it is a read only data.
Why is the table size a problem? I can imagine a few reasons, but it
would be nice to know which one you are trying to solve:

* The file size itself is a problem for shipping the file.
* The startup time is a problem and a compact table makes the dynamic
linker faster.
* The memory usage is a problem.

For the last one one thing that could be done is have something like
PT_GNU_RELRO but that tells the dynamic linker to unmmap the region
completely once it is done with the relocations.

In addition what is done for COFF, the other existing solution I know
is https://wiki.mozilla.org/Elfhack. In the case of mozilla the issue
was just the size of the binary being shipped I think.

Cheers,
Rafael

  parent reply	other threads:[~2017-04-27 20:04 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-01  0:00 Sriraman Tallam
2017-01-01  0:00 ` H.J. Lu
2017-01-01  0:00   ` Sriraman Tallam
2017-01-01  0:00 ` Cary Coutant
2017-01-01  0:00   ` Sriraman Tallam
2017-01-01  0:00   ` H.J. Lu
2017-01-01  0:00   ` Markus Trippelsdorf
2017-01-01  0:00   ` Florian Weimer
2017-01-01  0:00     ` Alan Modra
2017-01-01  0:00 ` Rafael Espíndola [this message]
2017-01-01  0:00   ` Sriraman Tallam
     [not found] <CAGWvnynFwXFGLj3tAVgDatn0zmuHcWHyRNuDvR+wRZCXLnar_A@mail.gmail.com>
2017-01-01  0:00 ` Rafael Avila de Espindola
2017-01-01  0:00   ` David Edelsohn
2017-01-01  0:00     ` Suprateeka R Hegde
2017-01-01  0:00       ` Florian Weimer
2017-01-01  0:00         ` Suprateeka R Hegde
2017-01-01  0:00           ` Sriraman Tallam via gnu-gabi
2017-01-01  0:00             ` Rahul Chaudhry via gnu-gabi
2017-01-01  0:00               ` Florian Weimer
2017-01-01  0:00                 ` Sriraman Tallam via gnu-gabi
2017-01-01  0:00                   ` Rahul Chaudhry via gnu-gabi
     [not found]                     ` <CAORpzuMftCGpXUObOyoFY0=jorMBDWEDbQJ23DifTNW3v-WA6Q@mail.gmail.com>
2017-01-01  0:00                       ` Rahul Chaudhry via gnu-gabi
2017-01-01  0:00                         ` Cary Coutant
2017-01-01  0:00                           ` Rahul Chaudhry via gnu-gabi
     [not found]                             ` <CAORpzuPYsSBJtypm3NDcfcgRzos3WO4JjkvgiqpyBYBhoqLVFA@mail.gmail.com>
2018-01-01  0:00                               ` Florian Weimer
2017-01-01  0:00               ` Cary Coutant
2017-01-01  0:00                 ` Rahul Chaudhry via gnu-gabi
2017-01-01  0:00                   ` Rahul Chaudhry via gnu-gabi
2017-01-01  0:00               ` Ian Lance Taylor via gnu-gabi

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