dynamic loading with ghc api?

[Don Stewart]

Using plugins with dynamic Haskell objects hasn't been tested in quite a while.

-- Don

On Thu, Apr 7, 2011 at 5:14 PM, Rob Nikander <rob.nikander at gmail.com> wrote:
> Is the 'plugins' package compatible with dynamic linking of the main
> program?   I ask because I wrote a test program using
> System.Plugins.load and it works fine, but when I link it to the GHC
> api using `ghc -dynamic ...' (which is nice cause it avoids the 50 MB
> executable),  it seg faults when it tries to call the function that it
> loaded from the .o file.  Maybe I need to compile the .o with
> something more than `ghc -c MyPlugin.hs'?
>
> Rob
>
> On Thu, Apr 7, 2011 at 3:35 PM, Don Stewart <dons00 at gmail.com> wrote:
>> Perhaps look at the plugins package source?
>>
>> -- Don
>>
>> On Thu, Apr 7, 2011 at 12:20 PM, Rob Nikander <rob.nikander at gmail.com> wrote:
>>> Hi all,
>>>
>>> I'd like to load a value from a .o file.  I've got...
>>>
>>> import ObjLink
>>> main = do
>>>  initObjLinker
>>>  loadObj "Thing.o"
>>>  resolveObjs
>>>  Just ptr <- lookupSymbol "Thing_value_closure"
>>>
>>> Is that the correct symbol to load for the name "value" in module
>>> "Thing"?  And if so, how to I get the haskell value out of the Ptr
>>> that I get from lookupSymbol?  I found some code to do it and it works
>>> value :: Int, but it seg faults if value :: Integer, or something more
>>> complex like a function.
>>>
>>> {-# LANGUAGE MagicHash #-}
>>> {-# LANGUAGE UnboxedTuples #-}
>>> ...
>>> let !(Ptr addr) = ptr
>>> in case addrToHValue# addr of
>>>    (# hval #) -> hval
>>>
>>> Is there some documentation for this that I'm missing?  I'm looking at
>>> haddock with just type signatures, like this:
>>>
>>> http://www.haskell.org/ghc/docs/7.0.3/html/libraries/ghc-7.0.3/ObjLink.html
>>>
>>> (I'm a haskell beginner.)
>>>
>>> thank you,
>>> Rob
>>>
>>> _______________________________________________
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>>> Glasgow-haskell-users at haskell.org
>>> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
>>>
>>
>
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