linker_unload

[Joachim Breitner]

Hi,


Am Mittwoch, den 03.12.2014, 11:18 +0100 schrieb Herbert Valerio Riedel:
> On 2014-12-03 at 09:48:58 +0100, Simon Peyton Jones wrote:
> For a non-failing linker_unload environment, the testprogram is linked
> against libgmp.so:
> 
> $ ldd tests/rts/linker_unload 
> 	linux-vdso.so.1 =>  (0x00007fff20f6c000)
> 	libgmp.so.10 => /usr/lib/x86_64-linux-gnu/libgmp.so.10 (0x00007f83c5bbb000)
> 	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f83c58b5000)
> 	librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f83c56ac000)
> 	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f83c54a8000)
> 	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f83c50e3000)
> 	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f83c4ec4000)
> 	/lib64/ld-linux-x86-64.so.2 (0x00007f83c5e76000)

and for a failing, it is not.


I further narrowed it down to the question of whether gcc passes
"--as-needed" to ld by default: If I pass "-optl-Wl,--no-as-needed" to
ghc when compiling linker_unload.c, it works there as well.


In some releases of Ubuntu, --as-needed is the default¹. Not sure why
Herbert does not see this behavior in a recent release (14.04).

I’m also not sure about the right fix: Should we just pass
-Wl,--no-as-needed to gcc always? But clearly there is a reason for this
flag becoming default. Can we set up things so that they work with
--as-needed?

Greetings,
Joachim




¹ https://lists.ubuntu.com/archives/ubuntu-devel-announce/2010-November/000783.html



-- 
Joachim “nomeata” Breitner
  mail at joachim-breitner.de • http://www.joachim-breitner.de/
  Jabber: nomeata at joachim-breitner.de  • GPG-Key: 0xF0FBF51F
  Debian Developer: nomeata at debian.org

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: This is a digitally signed message part
URL: <http://www.haskell.org/pipermail/ghc-devs/attachments/20141203/09718845/attachment.sig>