[GHC] #15397: Linking Issue on Ubuntu and Fedora with Provided Bindists (GHC-8.4.2)

[GHC]

#15397: Linking Issue on Ubuntu and Fedora with Provided Bindists (GHC-8.4.2)
-------------------------------------+-------------------------------------
           Reporter:  _recursion     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.4.4
          Component:  Compiler       |           Version:  8.4.2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Incorrect result
  Unknown/Multiple                   |  at runtime
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 It appears that the bindists being given to both ubuntu and fedora users
 are subtly broken. When attempting to link a binary depending on libffi,
 the linker picks up the copy of `libffi.so.7` found in the rts folder of
 the distribution. This means that at runtime, despite the systems in
 question having a copy of `libffi.so.6`, the binary can't find the correct
 shared library to link against.

 This does not happen on Arch Linux or Gentoo, as `/usr/lib` or
 `/usr/lib64` are included in their linker invocations respectively,
 allowing the linker to pick up the correct version of the dependency.

 You can reproduce the issue quickly by cloning [https://github.com/luna
 /luna-core Luna Core] and executing the following commands. I suggest
 doing this on an Ubuntu or Fedora system as I know it fails on those two
 distros.

 {{{
 stack build luna-shell --fast
 stack exec luna
 }}}

 You should see something along the lines of the following.

 {{{
 error while loading shared libraries: libffi.so.7: cannot open shared
 object file: No such file or directory
 }}}

 In essence, the reproduction steps are as follows:

 1. Create a project depending on libffi using ghc-8.4.2
 2. Build the project
 3. Execute it


 The ''expected'' result is that the binary links against the system copy
 of `libffi.so.6`, rather than the `libffi.so.7` provided in the ghc
 distribution.

 I can't guarantee that Ubuntu and Fedora are the only affected systems,
 but I know that Arch Linux and Gentoo were both fine with the provided
 bindists. All tested systems were x64, so I cannot confirm if the issue
 affects x86 bindists.

 The actual symptom appears to be a result of the linker never being given
 the path to the system library directory (e.g. `/usr/lib` or
 `/usr/lib64`), whereas on Arch and Gentoo, the linkline does contain that
 directory.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15397>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler