[GHC] #10161: GHC does not relink if a library's code changed

[GHC]

#10161: GHC does not relink if a library's code changed
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        Reporter:  nh2               |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Driver            |              Version:  7.8.4
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #10966            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by ezyang):

 So, I'm pretty sure the problem (in this bug) is this:

 1. You made an ABI-compatible change to an upstream library.
 2. Recompilation avoidance decides that myexe does not need to be
 recompiled (rightly so)
 3. The decision whether to relink or not depends purely on whether or not
 any local modules got recompiled. Which they did not.

 It sort of sounds like we need to store some extra metadata in the final
 linked executable which talks about the precise objects involved, so we
 know when to relink.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10161#comment:3>
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