[GHC] #7062: Spurious undefined reference to `openpty'

[GHC]

#7062: Spurious undefined reference to `openpty'
---------------------------------+------------------------------------------
    Reporter:  simonmar          |       Owner:                  
        Type:  bug               |      Status:  merge           
    Priority:  high              |   Milestone:  7.4.3           
   Component:  Compiler          |     Version:  7.4.2           
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
---------------------------------+------------------------------------------

Comment(by trommler):

 Replying to [comment:12 nus]:
 > Replying to [comment:8 trommler]:
 > I'm not sure what's going on with that build. After applying
 http://hackage.haskell.org/trac/ghc/changeset/301b37255fb9ea3abd634cf9caf774c6dab647b7
 to the pristine ghc-7.4.2 sources the `process001(dyn)` test from the
 7.4.2 testsuite finishes OK here.
 My executable also contains a RUNPATH tag in addition to the RPATH tag:
 {{{
 Dynamic section at offset 0x2d78 contains 27 entries:
   Tag        Type                         Name/Value
  0x0000000000000001 (NEEDED)             Shared library:
 [libHSprocess-1.1.0.2-ghc7.7.20120724.so]
  0x0000000000000001 (NEEDED)             Shared library:
 [libHSbase-4.6.0.0-ghc7.7.20120724.so]
  0x0000000000000001 (NEEDED)             Shared library: [libHSghc-
 prim-0.3.0.0-ghc7.7.20120724.so]
  0x0000000000000001 (NEEDED)             Shared library: [libHSrts-
 ghc7.7.20120724.so]
  0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
  0x000000000000000f (RPATH)              Library rpath:
 [/home/peter/projects/haskell/ghc-validate/libraries/process/dist-
 install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/directory/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/unix
 /dist-install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/bytestring/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/time
 /dist-install/build:/home/peter/projects/haskell/ghc-validate/libraries
 /old-locale/dist-install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/filepath/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/deepseq
 /dist-install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/array/dist-install/build:/home/peter/projects/haskell
 /ghc-validate/libraries/base/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/integer-
 gmp/dist-install/build:/home/peter/projects/haskell/ghc-validate/libraries
 /ghc-prim/dist-install/build:/home/peter/projects/haskell/ghc-
 validate/rts/dist/build]
  0x000000000000001d (RUNPATH)            Library runpath:
 [/home/peter/projects/haskell/ghc-validate/libraries/process/dist-
 install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/directory/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/unix
 /dist-install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/bytestring/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/time
 /dist-install/build:/home/peter/projects/haskell/ghc-validate/libraries
 /old-locale/dist-install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/filepath/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/deepseq
 /dist-install/build:/home/peter/projects/haskell/ghc-
 validate/libraries/array/dist-install/build:/home/peter/projects/haskell
 /ghc-validate/libraries/base/dist-
 install/build:/home/peter/projects/haskell/ghc-validate/libraries/integer-
 gmp/dist-install/build:/home/peter/projects/haskell/ghc-validate/libraries
 /ghc-prim/dist-install/build:/home/peter/projects/haskell/ghc-
 validate/rts/dist/build]
  0x000000000000000c (INIT)               0x401c00
 [snip]
 }}}

 The default on openSUSE's binutils is to {{{--enable-new-dtags}}} for ld.
 Then shared libraries will have both RUNPATH and RPATH. If I understand a
 discussion between Duncan Coutts and Andrew Suffield right
 [http://www.haskell.org/pipermail/cvs-ghc/2010-January/052251.html] then
 RUNPATH overrides RPATH . So I needed to look at RUNPATH. RUNPATH is only
 searched in the object that caused the load. Since {{{libHSdirectory}}}
 does not contain a RUNPATH but needs {{{libHSunix}}} the latter cannot be
 found. The RUNPATH in {{{process001}}} will not be searched as
 {{{process001}}} does not (directly) load {{{libHSunix}}} as a consequence
 of {{{--asneeded}}}.

 A temporary solution would be to add {{{--disable-new-dtags}}} to the
 linker flags in {{{settings}}}. I'll prepare a patch for this and add it
 to the ticket.

 Long term we should consider adding RUNPATHs to all libraries as Duncan
 suggested in the above posting.
 > > This matches nus' results with readelf above. In number 2) note that
 libHSunix... is missing in {{{readelf -d process001}}} output. That means
 the Rpath to libHSunix... is also not included in process001 and hence the
 "No such file or directory."
 > Perhaps you're checking a different executable? Here RPATH of the
 produced executable has the path to the directory containing `HSunix`:
 What I said about RPATH was wrong. My RPATH looks exactly like yours.
 Sorry about the confusion.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7062#comment:13>
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