#15848: ghc builds cbits with -fPIC even when -fPIC is not passed to ghc on linux -------------------------------------+------------------------------------- Reporter: watashi | Owner: watashi Type: bug | Status: new Priority: normal | Milestone: Component: Driver | Version: 8.7 Resolution: | Keywords: Operating System: Linux | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #15847, #12759 | Differential Rev(s): Phab:D5288 Wiki Page: | -------------------------------------+------------------------------------- Changes (by watashi): * owner: (none) => watashi * differential: => Phab:D5288 * related: #15847 => #15847, #12759 Old description:

ghc assumes that on linux, C compiler (e.g. gcc) will build non-PIC object code when no `-fPIC` is passed. But this is no longer true for recent gcc version on some distributions. e.g.

{{{ $ uname -a Linux watashi-arch32 4.18.5-arch1-1.0-ARCH #1 SMP PREEMPT Tue Aug 28 20:45:30 CEST 2018 i686 GNU/Linux $ gcc --version gcc (GCC) 7.3.1 20180312 $ touch dummy.c $ gcc -Q -v dummy.c 2>&1 | grep PIC options enabled: -fPIC -fPIE -faggressive-loop-optimizations }}}

We need pass `-fno-PIC` explicitly just like `-no-pie`.

In particular, this results in 300+ ext-interp related tests to fail on i386 when built with a gcc that has `-fPIC` on by default, as we don't support loading non-PIC .o built from .c on i386. (See #15847, fix this bug will mitigate #15847)

New description: ghc assumes that on linux, C compiler (e.g. gcc) will build non-PIC object code when no `-fPIC` is passed. But this is no longer true for recent gcc version on some distributions. e.g. {{{ $ uname -a Linux watashi-arch32 4.18.5-arch1-1.0-ARCH #1 SMP PREEMPT Tue Aug 28 20:45:30 CEST 2018 i686 GNU/Linux $ gcc --version gcc (GCC) 7.3.1 20180312 $ touch dummy.c $ gcc -Q -v dummy.c 2>&1 | grep PIC options enabled: -fPIC -fPIE -faggressive-loop-optimizations }}} We need pass `-fno-PIC` explicitly just like we have done for `-no-pie` (See #12759) In particular, this results in 300+ ext-interp related tests to fail on i386 when built with a gcc that has `-fPIC` on by default, as we don't support loading non-PIC .o built from .c on i386. (See #15847, fix this bug will mitigate #15847) -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15848#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#15848: ghc builds cbits with -fPIC even when -fPIC is not passed to ghc on linux -------------------------------------+------------------------------------- Reporter: watashi | Owner: watashi Type: bug | Status: closed Priority: normal | Milestone: 8.8.1 Component: Driver | Version: 8.7 Resolution: fixed | Keywords: Operating System: Linux | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #15847, #12759 | Differential Rev(s): Phab:D5288 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => closed * resolution: => fixed * milestone: => 8.8.1 Comment: Great catch, watashi! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15848#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler