[GHC] #8935: Obscure linker bug leads to crash in GHCi

[GHC]

#8935: Obscure linker bug leads to crash in GHCi
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        Reporter:  simonmar          |            Owner:  trommler
            Type:  bug               |           Status:  patch
        Priority:  high              |        Milestone:  7.8.3
       Component:  Runtime System    |          Version:  7.8.1-rc2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  GHCi crash        |       Difficulty:  Rocket Science
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by trommler):

 Replying to [comment:41 simonmar]:
 > @trommler, giving you the ticket.
 Thanks!
 >
 > Thinking about it, I'm less sure that `RTLD_LOCAL` will work now,
 because it won't allow us to load new libraries that depend on libraries
 we've previously loaded, and we definitely need to be able to do that.
 For libraries (SOs) coming from installed packages everything should be
 fine. The have a `NEEDED` tag for all dependencies and the system linker
 will `dlopen()` them and resolve the symbols.

 So for new libraries temporary SOs need to be produced the same way SOs in
 packages are, with `NEEDED` tags for all previously loaded libraries. The
 new library could potentially depend on all previously loaded libraries.

 I am thinking of something along the lines of:
 {{{
 ld -shared temp.o ... < -l for each library loaded so far >
 }}}

 Perhaps we could remove libraries from the list that are not needed by the
 new library by using `--as-needed` but I want to check first if this flag
 is GNU ld specific.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8935#comment:42>
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