#13935: AC_CHECK_FUNC yields incorrect result for pthread functions on NixOS causing build to fail -------------------------------------+------------------------------------- Reporter: mjvoge02 | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: Keywords: autoconf, | Operating System: Linux AC_CHECK_FUNC, configure, nixos | Architecture: x86_64 | Type of failure: None/Unknown (amd64) | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Code in [[GhcFile(configure.ac)]] incorrectly assesses that pthread functions will be available without explicitly providing `-lpthread` to gcc. This causes the build to fail. Forcing `need_lpthread=1` in [[GhcFile(configure.ac)]] causes the build to succeed and produce a perfectly functional GHC. From conversation on #GHC: "It looks like the combination of the following two commits has caused the breakage: e94bfb677298de3c4b4e0d1223fbc589849b79be, c0872bf99ff891e440f118bf9eea20b980c2cfca.[[br]] The first makes the configure script check if the `-lpthread` argument is required when building GHC, and the second uses that knowledge at runtime to decide whether to pass `-lpthread` when linking programs. [[br]] Stage 0 builds stage 1 just fine, since it doesn't have these commits and decides whether to pass `-lpthread` based purely on the platform. But the code from the first commit is yielding a false result (I don't know why), so stage 1 fails to build stage 2, since the second commit makes it use the false result to choose not to pass `-lpthread`." Also, doesn't determining the need for `-lpthread` like this have problematic implications for cross compilation? Whether `-lpthread` is required could be different between linking GHC and GHC doing linking (e.g. a cross compiler built on a system that does need the flag targeting a system that doesn't.) Ignoring that, using AX_PTHREAD or ACX_PTHREAD could potentially help resolve the issue. Relevant code from [[GhcFile(configure.ac)]]: {{{#!bash dnl Some platforms (e.g. Android's Bionic) have pthreads support available dnl without linking against libpthread. Check whether -lpthread is necessary dnl to use pthreads. dnl dnl Note that it is important that this happens before we AC_CHECK_LIB(thread) AC_MSG_CHECKING(whether -lpthread is needed for pthreads) AC_CHECK_FUNC(pthread_create, [ AC_MSG_RESULT(no) need_lpthread=0 ], [ AC_CHECK_LIB(pthread, pthread_create, [ AC_MSG_RESULT(yes) need_lpthread=1 ], [ AC_MSG_RESULT([no pthreads support found.]) need_lpthread=0 ]) ]) AC_DEFINE_UNQUOTED([NEED_PTHREAD_LIB], [$need_lpthread], [Define 1 if we need to link code using pthreads with -lpthread]) }}} System information: Linux nixos 4.9.30 x86_64 GNU/Linux gcc 5.4.0 ghc 7.10.3 Attempting to build GHC HEAD fails with {{{#!bash ... "inplace/bin/ghc-stage1" -hisuf hi -osuf o -hcsuf hc -static -O0 -H64m -Wall -Iincludes -Iincludes/dist -Iincludes/dist- derivedconstants/header -Iincludes/dist-ghcconstants/header -this-unit- id ghc-8.3 -hide-all-packages -i -icompiler/backpack -icompiler/basicTypes -icompiler/cmm -icompiler/codeGen -icompiler/coreSyn -icompiler/deSugar -icompiler/ghci -icompiler/hsSyn -icompiler/iface -icompiler/llvmGen -icompiler/main -icompiler/nativeGen -icompiler/parser -icompiler/prelude -icompiler/profiling -icompiler/rename -icompiler/simplCore -icompiler/simplStg -icompiler/specialise -icompiler/stgSyn -icompiler/stranal -icompiler/typecheck -icompiler/types -icompiler/utils -icompiler/vectorise -icompiler/stage2/build -Icompiler/stage2/build -icompiler/stage2/build/./autogen -Icompiler/stage2/build/./autogen -Icompiler/. -Icompiler/parser -Icompiler/utils -Icompiler/../rts/dist/build -Icompiler/stage2 -optP-DGHCI -optP-include -optPcompiler/stage2/build/./autogen/cabal_macros.h -package-id base-4.10.0.0 -package-id deepseq-1.4.3.0 -package-id directory-1.3.0.2 -package-id process-1.6.0.0 -package-id bytestring-0.10.8.2 -package-id binary-0.8.4.1 -package-id time-1.8.0.1 -package-id containers-0.5.10.2 -package-id array-0.5.1.2 -package-id filepath-1.4.1.2 -package-id template-haskell-2.12.0.0 -package-id hpc-0.6.0.3 -package-id transformers-0.5.2.0 -package-id ghc-boot-8.3 -package-id ghc-boot-th-8.3 -package-id ghci-8.3 -package-id unix-2.7.2.2 -package-id terminfo-0.4.1.0 -Wall -fno-warn-name-shadowing -this-unit-id ghc -XHaskell2010 -optc- DTHREADED_RTS -DGHCI_TABLES_NEXT_TO_CODE -DSTAGE=2 -Rghc-timing -O0 -no- user-package-db -rtsopts -Wnoncanonical-monad-instances -odir compiler/stage2/build -hidir compiler/stage2/build -stubdir compiler/stage2/build -dynamic-too -c compiler/hsSyn/HsTypes.hs -o compiler/stage2/build/HsTypes.o -dyno compiler/stage2/build/HsTypes.dyn_o includes/rts/OSThreads.h:58:0: error: error: undefined reference to 'pthread_mutex_trylock' | 58 | return pthread_mutex_trylock(mutex); | ^ includes/rts/OSThreads.h:58:0: error: error: undefined reference to 'pthread_mutex_trylock' | 58 | return pthread_mutex_trylock(mutex); | ^ rts/posix/OSThreads.c:137:0: error: error: undefined reference to 'pthread_create' | 137 | int result = pthread_create(pId, NULL, (void *(*)(void *))startProc, param); | ^ rts/posix/OSThreads.c:139:0: error: error: undefined reference to 'pthread_detach' | 139 | pthread_detach(*pId); | ^ rts/posix/OSThreads.c:141:0: error: error: undefined reference to 'pthread_setname_np' | 141 | pthread_setname_np(*pId, name); | ^ rts/posix/OSThreads.c:184:0: error: error: undefined reference to 'pthread_key_create' | 184 | if ((r = pthread_key_create(key, NULL)) != 0) { | ^ rts/posix/OSThreads.c:203:0: error: error: undefined reference to 'pthread_setspecific' | 203 | if ((r = pthread_setspecific(*key,value)) != 0) { | ^ rts/posix/OSThreads.c:212:0: error: error: undefined reference to 'pthread_key_delete' | 212 | if ((r = pthread_key_delete(*key)) != 0) { | ^ rts/posix/OSThreads.c:233:0: error: error: undefined reference to 'pthread_create' | 233 | int result = pthread_create(&tid, NULL, | ^ rts/posix/OSThreads.c:236:0: error: error: undefined reference to 'pthread_detach' | 236 | pthread_detach(tid); | ^ rts/posix/OSThreads.c:192:0: error: error: undefined reference to 'pthread_getspecific' | 192 | return pthread_getspecific(*key); | ^ rts/posix/OSThreads.c:371:0: error: error: undefined reference to 'pthread_kill' | 371 | pthread_kill(id, SIGPIPE); | ^ rts/posix/itimer/Pthread.c:171:0: error: error: undefined reference to 'pthread_create' | 171 | if (! pthread_create(&thread, NULL, itimer_thread_func, (void*)handle_tick)) { | ^ rts/posix/itimer/Pthread.c:210:0: error: error: undefined reference to 'pthread_join' | 210 | if (pthread_join(thread, NULL)) { | ^ rts/posix/itimer/Pthread.c:173:0: error: error: undefined reference to 'pthread_setname_np' | 173 | pthread_setname_np(thread, "ghc_ticker"); | ^ rts/posix/itimer/Pthread.c:214:0: error: error: undefined reference to 'pthread_detach' | 214 | pthread_detach(thread); | ^ includes/rts/OSThreads.h:58:0: error: error: undefined reference to 'pthread_mutex_trylock' | 58 | return pthread_mutex_trylock(mutex); | ^ collect2: error: ld returned 1 exit status `gcc' failed in phase `Linker'. (Exit code: 1) make[1]: *** [iserv/ghc.mk:72: iserv/stage2/build/tmp/ghc-iserv] Error 1 make[1]: *** Waiting for unfinished jobs.... <> <> <> <> make: *** [Makefile:127: all] Error 2 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13935 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler