On Fri, 2004-04-30 at 17:36, Simon Marlow wrote:
On 30 April 2004 11:26, Duncan Coutts wrote:
Could someone remind me what the remaining issues are in getting ghc to build Haskell modules/packaged into unix .so shared libraries?
It might be possible to do this, but only if you want to do dlopen()-style linking at runtime. Linking a haskell binary against Haskell .so libraries still isn't possible - I had another look at this recently, and although one of the obstacles has been removed, there are others (details available on request).
Details would be interesting.
Any remaining issues to do with dlopen()ing a Haskell .so library are probably to do with CAFs. The dynamically loaded code needs to call newDynCAF() instead of newCAF() in a CAF's entry code - this is normally arranged by the RTS linker, but for a .so you'll have to do it some other way, like getting the compiler to emit the different call, or doing some CPP magic (but only for -fvia-C). Any reasonable patches to implement this will be incorporated.
Does that involve changing what reference get linked to which symbols or would it be a matter of finding a bunch of symbols & calling them after doing a dlopen() ? Another way of asking the same thing is can the calling newDynCAF be done in a separate phase (ie after dlopen()) or is it intimately part of the linking process? There seem to be several people interested in doing plug-in systems with dynamically loaded modules. I just came across this report: http://www.cs.chalmers.se/Cs/Grundutb/Kurser/afp/distinguished/dynamiclinker... Duncan