[GHC] #11470: Support changing cross compiler target at runtime

[GHC]

#11470: Support changing cross compiler target at runtime
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        Reporter:  ezyang            |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11378            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by angerman):

 Just to add a note on LLVM. If we would have an architecture independent
 IR[1] backend, and would just emit bitcode (which we could do from textual
 or bitcode IR), we could ask LLVM to produce the relevant executables for
 the relevant targets. There is however the question about how much
 architecture dependent information is used up until the Cmm phase from
 which the LLVM backend takes over and how much architecture dependent
 information we use in the llvm backend. We'd finally have to see about the
 mangler as well.

 If we therefore got a bitcode emitting ghc, we would almost get all llvm
 backends for free.

 ----

 [1]: As far as I understand, you can have architecture independent IR;
 which however requires careful instruction selection.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11470#comment:9>
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