[GHC] #15338: ghc-pkg misbehaves after possible miscompilation on m68k and sh4

[GHC]

#15338: ghc-pkg misbehaves after possible miscompilation on m68k and sh4
-------------------------------------+-------------------------------------
           Reporter:  glaubitz       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           Keywords:                 |  Operating System:  Linux
       Architecture:  m68k           |   Type of failure:  Incorrect result
                                     |  at runtime
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 We have observed in Debian that GHC can produce a erratically behaving
 version of ghc-pkg which causes issues when piping it's output to another
 program.

 Example:

 {{{
 make_setup_recipe
 Running ghc --make Setup.hs -o debian/hlibrary.setup
 [1 of 1] Compiling Main             ( Setup.hs, Setup.o )
 Linking debian/hlibrary.setup ...
 . /usr/share/haskell-devscripts/Dh_Haskell.sh && \
 configure_recipe
 Running debian/hlibrary.setup configure --ghc -v2 --package-
 db=/var/lib/ghc/package.conf.d --prefix=/usr --libdir=/usr/lib/haskell-
 packages/ghc/lib --libexecdir=/usr/lib --builddir=dist-ghc --ghc-option
 =-optl-Wl\,-z\,relro --haddockdir=/usr/lib/ghc-doc/haddock/base-prelude-/
 --datasubdir=base-prelude --htmldir=/usr/share/doc/libghc-base-prelude-
 doc/html/ --enable-library-profiling
 Configuring base-prelude-1.2.1...
 Warning: cannot determine version of /usr/bin/ghc-pkg :
 ""
 hlibrary.setup: The program 'ghc-pkg' is required but the version of
 /usr/bin/ghc-pkg could not be determined.
 }}}

 (Full log: https://buildd.debian.org/status/fetch.php?pkg=haskell-base-
 prelude&arch=m68k&ver=1.2.1-1&stamp=1530588494&raw=0)

 Examining the behavior of the affected ghc-pkg binary on m68k shows what's
 going on:

 {{{
 root at pacman:~# uname -a
 Linux pacman 4.16.0-2-m68k #1 Debian 4.16.16-1 (2018-06-19) m68k GNU/Linux
 root at pacman:~# ghc-pkg --version
 GHC package manager version 8.2.2
 root at pacman:~# ghc-pkg --version | cat
 root at pacman:~#
 }}}

 Comparing that to an x86_64 machine shows that piping to cat should
 actually output something:

 {{{
 glaubitz at epyc:~$ uname -a
 Linux epyc 4.16.0-2-amd64 #1 SMP Debian 4.16.12-1 (2018-05-27) x86_64
 GNU/Linux
 glaubitz at epyc:~$ ghc --version
 The Glorious Glasgow Haskell Compilation System, version 8.2.2
 glaubitz at epyc:~$ ghc --version | cat
 The Glorious Glasgow Haskell Compilation System, version 8.2.2
 glaubitz at epyc:~$
 }}}

 Further investigation shows that the problem is partially resolved when
 building GHC with reduced optimization:

 {{{
         echo "SRC_HC_OPTS += -O0 -H64m" >> mk/build.mk
         echo "GhcStage1HcOpts = -O" >> mk/build.mk
         echo "GhcStage2HcOpts = -O0" >> mk/build.mk
         echo "GhcLibHcOpts = -O" >> mk/build.mk
 }}}

 The above issue goes away, but ghc-pkg itself still shows some strange
 behavior:

 {{{
 make_setup_recipe
 Running ghc --make Setup.hs -o debian/hlibrary.setup
 [1 of 1] Compiling Main             ( Setup.hs, Setup.o )
 Linking debian/hlibrary.setup ...
 . /usr/share/haskell-devscripts/Dh_Haskell.sh && \
 configure_recipe
 Running debian/hlibrary.setup configure --ghc -v2 --package-
 db=/var/lib/ghc/package.conf.d --prefix=/usr --libdir=/usr/lib/haskell-
 packages/ghc/lib --libexecdir=/usr/lib --builddir=dist-ghc --ghc-option
 =-optl-Wl\,-z\,relro --haddockdir=/usr/lib/ghc-doc/haddock/microlens-
 ghc-0.4.8.0/ --datasubdir=microlens-ghc --htmldir=/usr/share/doc/libghc-
 microlens-ghc-doc/html/ --enable-library-profiling
 Configuring microlens-ghc-0.4.8.0...
 hlibrary.setup: ghc-pkg dump failed: dieVerbatim: user error
 (hlibrary.setup:
 '/usr/bin/ghc-pkg' exited with an error:
 ghc-pkg: <stdout>: commitBuffer: invalid argument (invalid character)
 )
 }}}

 (Full log: https://buildd.debian.org/status/fetch.php?pkg=haskell-
 microlens-ghc&arch=m68k&ver=0.4.8.0-2&stamp=1529960552&raw=0)

 To reproduce the issue, GHC can be tested using QEMU which has pretty good
 support for the m68k target these days.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15338>
GHC <http://www.haskell.org/ghc/>
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