[GHC] #12573: Allow the user to pick the address that the RTS reserves for the heap

[GHC]

#12573: Allow the user to pick the address that the RTS reserves for the heap
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        Reporter:  bitonic           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.0.2
       Component:  Runtime System    |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by tmcdonell):

 @bitonic my current (partially working) solution is to use an
 `__attribute__((constructor))` function to `mmap` the region that
 CUDA/OpenCL requires before the RTS initialises. The RTS will then avoid
 it and you can `munmap` it right before initialising CUDA/OpenCL:

 https://github.com/tmcdonell/cuda/blob/hotfix/ghc-8/cbits/init.c

 You can also initialise OpenCL directly in the constructor function, but
 then you'll spin up the GPU many times during compilation/haddock (every
 time a package loads your library). (This is simpler and what the master
 branch of the above repo does, actually.)

 Both those approaches work for compiled programs, but not in ghci, and I
 haven't had a chance to dig to the bottom of it yet.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12573#comment:3>
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