[GHC] #11784: panic "hscCmmFile: no_mod" with `-v2 and above

[GHC]

#11784: panic "hscCmmFile: no_mod" with `-v2 and above
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        Reporter:  erikd             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by bgamari):

 The problem here is that `hscCompileCmmFile` needs a `Module` to give to
 `CodeOutput.codeOutput`. The downstream uses of this `Module` are,
 * `outputForeignStubs`: needs a string to form the stem of the stub
 filename
 * `PIC.howToAccessLabel`: calls `CLabel.labelDynamic`, which,
   * then wants to compare it against another `Module` taken from a
 `HpcTicksLabel`
   * and uses it to call `Packages.isDllName`

 Given that `PIC.howToAccessLabel` hasn't blowing up due to the bottoming
 `Module`s we give it for C-- files, I suppose it should be safe for
 `hscCompileCmmFile` to simply make up a module name to give to the
 backend.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11784#comment:3>
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