[GHC] #12735: Evaluate the feasibility of using lld for linking

[GHC]

#12735: Evaluate the feasibility of using lld for linking
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        Reporter:  bgamari           |                Owner:
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Runtime System    |              Version:  8.0.1
  (Linker)                           |
      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 bgamari):

 Replying to [comment:2 dobenour]:
 > I would like to investigate a different approach: split the RTS linker
 as a C library that can be used by other projects, and which exposes a C
 API.  GHC would then depend on this library.

 I actually had a look at the `lld` codebase a few weeks ago and my initial
 impressions were that it isn't terribly well-suited to be used as a
 runtime linker. I offers a lot of parsing and relocation logic, but it
 lacks any support for managing mappings and the like.

 Consequently, I think the option that you suggest (which erikd has also
 advocated for in the past) is the only way forward. I would love to see it
 happen, but it will take some time. Currently our runtime linker is sorely
 in need of tests; this makes any sort of large-scale refactoring quite
 risky. `lld`'s testsuite may be a good source of inspiration (and perhaps
 even tests!) for fixing this.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12735#comment:3>
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