[GHC] #9038: Foreign calls don't make their arguments look strict

[GHC]

#9038: Foreign calls don't make their arguments look strict
-------------------------------------+-------------------------------------
              Reporter:  tibbe       |            Owner:
                  Type:  bug         |           Status:  infoneeded
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.2
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:  1592
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------

Comment (by tibbe):

 I might have been mistaken. I read the core for `add3` above and assumed
 that since `add3` isn't worker-wrappered the argument wouldn't be unboxed.
 I tried calling add3 (which is really the
 `System.Metrics.Distribution.add` function in the ekg-core package)
 function in this little test program

 {{{
 module Test where

 import System.Metrics.Distribution

 test :: Distribution -> IO ()
 test distrib = add distrib 1.0
 }}}

 and things seem to be unboxed correctly.

 Here's the demand signature for `add3`:

 {{{
 add3
   :: Distribution
      -> Double
      -> Int64
      -> State# RealWorld
      -> (# State# RealWorld, () #)
 [GblId,
  Arity=4,
  Caf=NoCafRefs,
  Str=DmdType <L,1*U(U)><L,1*U(U)><L,1*U(U)><L,U>,
  Unf=Unf{Src=<vanilla>, TopLvl=True, Arity=4, Value=True,
          ConLike=True, WorkFree=True, Expandable=True,
          Guidance=IF_ARGS [0 20 20 0] 156 30}]
 }}}

 How do I read the `DmdType <L,1*U(U)><L,1*U(U)><L,1*U(U)><L,U>` line?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9038#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler