[GHC] #9438: Dynamic GHCi doesn't support static libraries

[GHC]

#9438: Dynamic GHCi doesn't support static libraries
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        Reporter:  egl               |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.8.3
  (Linking)                          |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHCi crash        |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #8164, #14708,    |  Differential Rev(s):  Phab:D4589
  #15032                             |
       Wiki Page:                    |
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Comment (by Phyx-):

 @bgamari It certainly *can* be implemented, but it really depends on how
 `DYNAMIC_GHC_PROGRAMS` is implemented.

 I haven't looked at the exact implementation but I would imagine, that in
 order for this to work, the .so must export all symbols as globals. I
 suspect (without looking) that ghc is linking the shared lib using
 `--whole-archive`.

 C static shared archives wouldn't be must of an issue. If you have no
 reference to the C code in your own code it doesn't matter if the symbols
 are not there. As you can't directly call C code anyway.

 static Haskell libraries are a different issue, loading a static archive
 would require all it's symbols to also be exported. Two libraries with the
 exact same z-encoded symbol names would produce a duplicate symbol error,
 while this need not be the case normally.

 This is why I *think* it's currently not supported. An obvious work-around
 would be to create multiple .so and link them in the same order as the
 static archives.

 So I think it can be supported, but will require a bit of changes to
 `DYNAMIC_GHC_PROGRAMS`. You'd also have to track these archives. It would
 be a bit annoying to recompile them on every scope change when they didn't
 change. A totally naive implementation would be a bit of a performance
 hit.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9438#comment:12>
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