[GHC] #7718: ios patch no 8: adjustor pools

[GHC]

#7718: ios patch no 8: adjustor pools
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  Reporter:  StephenBlackheath  |          Owner:         
      Type:  feature request    |         Status:  patch  
  Priority:  normal             |      Milestone:  7.8.1  
 Component:  Compiler           |        Version:  7.7    
Resolution:                     |       Keywords:         
        Os:  Other              |   Architecture:  arm    
   Failure:  None/Unknown       |     Difficulty:  Unknown
  Testcase:                     |      Blockedby:         
  Blocking:  7724               |        Related:         
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Comment(by StephenBlackheath):

 igloo: I think this is correct (this whole business is quite complicated):

 On most platforms (but not iOS) libffi gives executable and writable
 pointers that are the same. i386 and x86_64 on all OSes including Linux do
 their own adjustors (which assume exec & writable are the same).

 On iOS libffi requires exec & writable pointers to be different and so we
 need a hash table to associate them. Most platforms do not require this
 overhead, so I've left them untouched except for abstracting the
 difference between executable/writable pointers a little bit using an
 explicit execToWritable() which is a no-op on most platforms.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7718#comment:15>
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