[GHC] #12606: Linux (ELF) Support for "ghc -static -shared"

[GHC]

#12606: Linux (ELF) Support for "ghc -static -shared"
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           Reporter:  tmobile           |             Owner:
               Type:  feature request   |            Status:  new
           Priority:  normal            |         Milestone:  ⊥
          Component:  Compiler          |           Version:  8.0.1
           Keywords:                    |  Operating System:  Linux
       Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
          Test Case:                    |        Blocked By:
           Blocking:                    |   Related Tickets:
Differential Rev(s):                    |         Wiki Page:
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 On some platforms it is possible to create a stand-alone shared library
 out of some object `Foo.o` including foreign exports with something like:

 `ghc -static -shared Foo.o ...`

 The resulting library will have `Foo`'s dependencies including `base` as
 well as the RTS statically linked in. On BSDs this is possible because
 generating position independent code is the default there, and on Windows
 this is possible because the dynamic loader uses some magic that doesn't
 require position independent code. Unfortunately on Linux this is not
 possible because `libHSbase`, `libHSrts`, etc. are not built with `-fPIC`
 unless one specifically asks for it when building GHC. As far as I know
 this is the only way to get `-static -shared` to work on this platform.

 There are use cases for compiling Haskell code into a single shared object
 that does not have additional runtime dependencies. Suppose one wishes to
 write a plugin for a program in Haskell. It would be nice to provide the
 plugin as a single shared object, rather than requiring GHC's libraries to
 be present at runtime as well.

 An easy solution might be adding a switch to the configure script or
 `build.mk` to make it easier to build GHC+libs with `-fPIC` on Linux.
 Ideally it would be possible to build and install both PIC and non-PIC
 libraries and have GHC choose the correct one at link time based on the
 flags and target platform, since PIC code carries a small
 space/performance overhead and isn't necessary on Linux in most cases.

 I don't know my way around GHC(outside of the GHC API) or the build system
 that well yet, but if adding extra build system flags and GHC link-time
 flag handling code to make this work is an acceptable solution I'm happy
 to spend the time to get this working.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12606>
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