[GHC] #8834: 64-bit windows cabal.exe segfaults in GC

[GHC]

#8834: 64-bit windows cabal.exe segfaults in GC
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        Reporter:  awson          |            Owner:  jstolarek
            Type:  bug            |           Status:  patch
        Priority:  highest        |        Milestone:  7.8.1
       Component:  Compiler       |          Version:  7.8.1-rc2
      Resolution:                 |         Keywords:
Operating System:  Windows        |     Architecture:  x86_64 (amd64)
 Type of failure:  Runtime crash  |       Difficulty:  Unknown
       Test Case:                 |       Blocked By:
        Blocking:                 |  Related Tickets:
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Comment (by jstolarek):

 Replying to [comment:58 simonmar]:
 > I believe `mingw32_HOST_OS` is defined on 64-bit Windows.
 Doesn't the output from my small C program suggest otherwise? Am I missing
 something here?

 > You can test this with `ghc --info` on your 64-bit Windows GHC.
 {{{
 (...)
  ,("target os","OSMinGW32")
  ,("target arch","ArchX86_64")
 (...)
  ,("Build platform","x86_64-unknown-mingw32")
  ,("Host platform","x86_64-unknown-mingw32")
  ,("Target platform","x86_64-unknown-mingw32")
 (...)
 }}}

 > glibc is completely irrelevant here. memchr comes from system dll
 msvcrt.dll and I doubt it is wrong.

 Hmm... I doubt we can take a look at source of that dll ;-) awson, could
 you verify that change in `MachRegs.h` fixes the bug? You might need to
 recompile GHC from scratch, at least I had to do so because the changes
 weren't picked up after partial recompilation. Note: don't test that with
 latest HEAD as it contains Simon's temporary fix based on your earlier
 patch.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8834#comment:60>
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