code review 674041: Limit visible symbols in the shared library.

Limit visible symbols in the shared library.

[rsc1, 2010-04-13 21:07:23]

Looks great, thanks.

[Stefano Rivera, 2010-04-14 09:05:08]

On 2010/04/13 21:07:23, rsc1 wrote:
> Looks great, thanks.

There's an improved version in http://code.google.com/p/re2/issues/detail?id=16

For some reason Rietveld let me post this, but since then I haven't been able to
modify it or submit any more re2 changes.

[rsc, 2010-04-14 17:49:25]

> There's an improved version in
> http://code.google.com/p/re2/issues/detail?id=16
>
> For some reason Rietveld let me post this, but since then I haven't been
> able to modify it or submit any more re2 changes.

What are you running to modify it?  It sounds like maybe
you are running hg submit instead of hg mail or hg upload?

I've applied these in my local client, with some tweaks
to make them work on OS X too.  I'll submit them later
today.

Thanks again.
Russ

[Stefano Rivera, 2010-04-16 08:33:53]

Hello rsc (cc: re2-dev@googlegroups.com),

Please take another look.

[rsc, 2010-04-16 19:21:10]

*** Submitted as http://code.google.com/p/re2/source/detail?r=4b010fadadac ***

Add Makefile rules building a shared library.

This patch was necessary for packaging RE2 for Debian.
Fixes issue 16.

R=rsc
CC=re2-dev
http://codereview.appspot.com/674041

Committer: Russ Cox <rsc@swtch.com>

[rsc, 2010-04-16 19:22:51]

I've submitted this with some modifications to make it
work on OS X, and I also made the shared object directory obj/so
so that all the generated files are contained to obj/.
I avoided the linker script in hopes of doing something
that has a chance to work with other linkers, but if
you can explain why it's necessary I'm happy to
revisit the issue.

Thanks.
Russ

[stefano_rivera.za.net, 2010-04-19 13:44:45]

Hi Russ (2010.04.16_21:22:47_+0200)
> and I also made the shared object directory obj/so so that all the
> generated files are contained to obj/.

Much neater.

> I avoided the linker script in hopes of doing something that has a
> chance to work with other linkers, but if you can explain why it's
> necessary I'm happy to revisit the issue.

It's simply to reduce the number of symbols exposed in the shared
library, which means the soname won't need to be bumped as often.

There's no reason that applications linking to the shared library should
be using functions not defined in the installed headers.

So, no. It isn't necessary but it's useful (and I'll continue using it
in the Debian re2 package).

SR

-- 
Stefano Rivera
  http://tumbleweed.org.za/
  

[rsc, 2010-04-19 14:39:07]

> There's no reason that applications linking to the shared library should
> be using functions not defined in the installed headers.
>
> So, no. It isn't necessary but it's useful (and I'll continue using it
> in the Debian re2 package).

I see.  Sounds good, thanks.

Russ

[Stefano Rivera, 2010-04-23 14:29:27]

Hello re2-dev@googlegroups.com (cc: rsc),

Please take another look.

[Stefano Rivera, 2010-04-23 20:21:42]

Hello re2-dev@googlegroups.com (cc: re2-dev@googlegroups.com, rsc),

Please take another look.

[rsc1, 2010-04-30 06:18:33]

I thought the plan was to just maintain this file
on the side in Debian.  It seems pretty clunky to me,
but I guess that's just the way shared libraries are.

What is being excluded?  The list seems fairly broad
(and rightly so).

[Stefano Rivera, 2010-04-30 06:56:44]

On 2010/04/30 06:18:33, rsc1 wrote:
> I thought the plan was to just maintain this file
> on the side in Debian.

Ah, sorry I misunderstood your reply.

> What is being excluded?

Everything that isn't in the installed headers.

[rsc, 2010-04-30 07:08:06]

>> What is being excluded?
>
> Everything that isn't in the installed headers.

I ran nm on the shared object to see what that meant.
Wow that's a lot of junk!  Okay, I'll apply the patch.  ;-)

Russ

[Stefano Rivera, 2010-04-30 14:03:52]

Hello rsc (cc: re2-dev@googlegroups.com),

Please take another look.

[rsc_swtch, 2010-04-30 19:48:34]

LGTM

Thanks.  I renamed libre2.symbols.linux to libre2.symbols.

[rsc, 2010-04-30 19:48:59]

*** Submitted as http://code.google.com/p/re2/source/detail?r=532397377870 ***

Limit visible symbols in the shared library.

R=rsc
CC=re2-dev
http://codereview.appspot.com/674041

Committer: Russ Cox <rsc@swtch.com>