[GHC] #15990: Dynamically built GHC crashes on MacOS

[GHC]

#15990: Dynamically built GHC crashes on MacOS
-------------------------------------+-------------------------------------
           Reporter:  harpocrates    |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.8.1
          Component:  Build System   |           Version:  8.7
  (Hadrian)                          |
           Keywords:                 |  Operating System:  MacOS X
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 Since 79d5427e1f9de02c0b171bf5db46b6b49c6f85e3 (which add support for
 dynamically linking GHC), the default `./hadrian/build.sh` is broken for
 MacOS. In particular, the `ghc` built always crashes with a "Symbol not
 found" error. Example:

 {{{
 $ ./hadrian/build.sh -j -c
 # << fails shortly after building first ghc >>
 $ _build/stage1/bin/ghc
 dyld: Symbol not found: _ffi_type_double
   Referenced from: _build/stage1/lib/../lib/x86_64-osx-
 ghc-8.7.20181202/libHSghci-8.7-ghc8.7.20181202.dylib
   Expected in: flat namespace
  in _build/stage1/lib/../lib/x86_64-osx-
 ghc-8.7.20181202/libHSghci-8.7-ghc8.7.20181202.dylib
 [1]    52701 abort      _build/stage1/bin/ghc

 }}}

 See
 https://phabricator.haskell.org/rGHC79d5427e1f9de02c0b171bf5db46b6b49c6f85e3
 for more discussion. The core of the issue seems to be that
 `-Wl,-dead_strip_dylibs` accidentally strips some essential libraries
 (`libffi` is one of these).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15990>
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