#12816: Link error with GOLD linker -------------------------------------+------------------------------------- Reporter: hsyl20 | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.2 Component: Compiler | Version: 8.1 (Linking) | Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Building GHC (amd64) | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- 1. I think we should add "pthread" to the list of extra-libs in "rts/package.conf.in" for the threaded RTS on UNIX-like host OSes. 2. we should include MachDeps.h in "rts/package.conf.in" Current master branch (2e8463b232054b788b73e6551947a9434aa76009) build is broken on my system[0]. When ghc-stage1 tries to produce ghc-stage2, I get: {{{ /home/hsyl20/repo/ghc/rts/dist/build/libHSrts_thr-ghc8.1.20161107.so: error: undefined reference to 'pthread_create' /home/hsyl20/repo/ghc/rts/dist/build/libHSrts_thr-ghc8.1.20161107.so: error: undefined reference to 'pthread_detach }}} (logs: http://pastebin.com/EbqEx6Gg ) I have tracked down the regression to the following recent commit: a977c96537bb7077c6445f02db98636b150e6e14 If I revert this commit, it builds. However I think this commit has only revealed the bug: if I add "pthread" to the list of extra-libs in "rts/package.conf.in", it builds too. We already add it on freebsd and openbsd but not on Linux. I think I have finally found out why other devs on #ghc haven't noticed this bug: my system uses the GOLD linker (because of #12748), but if I switch back to the BFD linker, it builds without error. While investigating this bug, I have noticed that linker flags for 64-bit atomic ops introduced by https://git.haskell.org/ghc.git/commitdiff/c06e3f46d24ef69f3a3d794f5f604cb8c... aren't set while they should: WORD_SIZE_IN_BITS isn't defined because we don't include MachDeps.h [0] x86-64, ArchLinux (Linux 4.8.6), GNU gold (GNU Binutils 2.27) 1.12, gcc (GCC) 6.2.1 20160830 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12816 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler