[GHC] #10383: AArch64: get GHC Calling convention working

[GHC]

#10383: AArch64: get GHC Calling convention working
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        Reporter:  erikd                |                Owner:  erikd
            Type:  feature request      |               Status:  new
        Priority:  normal               |            Milestone:  8.0.1
       Component:  Compiler             |              Version:  7.11
      Resolution:                       |             Keywords:
Operating System:  Unknown/Multiple     |         Architecture:  aarch64
 Type of failure:  Building GHC failed  |            Test Case:
      Blocked By:                       |             Blocking:
 Related Tickets:                       |  Differential Rev(s):
       Wiki Page:                       |
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Comment (by edmund):

 That sounds good!

 Are you sure that commit cc4522de4b60d975836a444a61a123011a496349 ("Fix
 clobbered regs list for aarch64 StgRun") is correct and necessary?
 Firstly, why is "%d15" missing from the list? Secondly, why are callee-
 save registers being saved and restored by the assembly code AND being
 described as clobbered so that the C compiler generates code to save and
 restore them? Isn't that just going to result in all those registers being
 saved and restored twice?

 However, it presumably doesn't hurt the correctness, so perhaps you should
 for now just add "%d15" to the list and insert a warning comment: "Callee-
 save registers are perhaps being saved and restored twice, redundantly!"

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10383#comment:34>
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