#7478: setSessionDynFlags does not always work -------------------------------------+------------------------------------- Reporter: edsko | Owner: Type: bug | Status: new Priority: high | Milestone: 7.12.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: ghc- Related Tickets: | api/T7478 | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by bherzog): I observe the same problem as [comment:8 thoughtpolice], also on a 32 bit Linux system (debian Wheezy), but with ghc master 7b042d5adabdb0fc06286db1a7f9cbf1e9fd1fbf. I have analysed it a bit and I think I have a solution or a least a work-around. On my system, the flags returned by `getSessionDynFlags` in `T7478.hs` are inconsistent with regard to dynamic vs. static linking. The `ways` list is empty, so in particular does not contain `WayDyn`, but at the same time, `Opt_Static` is not in `generalFlags`. This state of the flags is a bit contradictory, because AFAICT, there's some code that only looks at the presence of `WayDyn` when deciding whether a static or dynamic build has been requested while some other code only looks at `Opt_Static`. A missing `WayDyn` means to link statically, whereas a missing `Opt_Static` means linking dynamically. So the code expects this to be more consistent, which is also apparent from the fact that the `updateWays` function sets/unsets `Opt_Static` depending on the absence/presence of `WayDyn`. A workaround that works for me is to extend `defaultDynFlags` so that it applies `updateWays` to the `DynFlags` value it creates. I'm not sure that's the correct solution, though. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7478#comment:17 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler