[GHC] #12622: Unboxed static pointers lead to missing SPT entries

[GHC]

#12622: Unboxed static pointers lead to missing SPT entries
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        Reporter:  mboes             |                Owner:
                                     |  facundo.dominguez
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2709
       Wiki Page:                    |  Phab:D2720
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Comment (by facundo.dominguez):

 > I'm betting that if we had a top-level binding x = makeStatic e then it
 would never get inlined anyway.

 Indeed, I would hope GHC has no incentive to inline it.

 > You say that FloatOut would have go treat makeStatic specially, when not
 currently treat StaticPtr specially. Why?

 The SetLevels pass checks if a soon-to-be new top-level binding is a
 static pointer to determine what kind of Id to produce for the new binding
 (bindings of StaticPtrs need to be of //exported// kind). But so far the
 SetLevels pass decides on its own that the static pointer needs to be
 floated, because, I presume, most or all data constructor applications are
 treated like that.

 If we want SetLevels to float `makeStatic e`, we probably will have to
 modify the decision procedure to treat `makeStatic e` unlike other
 function applications and always float it.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12622#comment:15>
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