[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:  7.12.1
       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 Revisions:
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Comment (by erikd):

 Had a further (at least 3rd or 4th) look at the Aarch64 version of the
 `StgRun` function in `rts/StgCRun.c`. I noticed that some some of the
 registers that are pushed and popped on/off the stack were not listed in
 the "clobbered registers" part of the `__asm__` definition.

 Came up with this patch:

 {{{
 commit 5f75cbcea67cbb587a7d640f6241469744ab026f
 Author: Erik de Castro Lopo <erikd at mega-nerd.com>
 Date:   Wed Jun 3 05:54:23 2015 +0000

     rts: Fix clobbered registers list in aarch64 StgRun

 diff --git a/rts/StgCRun.c b/rts/StgCRun.c
 index 02ec532..46d7f11 100644
 --- a/rts/StgCRun.c
 +++ b/rts/StgCRun.c
 @@ -820,8 +820,14 @@ StgRun(StgFunPtr f, StgRegTable *basereg) {

        : "=r" (r)
        : "r" (f), "r" (basereg), "i" (RESERVED_C_STACK_BYTES)
 -        : "%x19", "%x20", "%x21", "%x22", "%x23", "%x24", "%x25", "%x26",
 "%x27", "%x28",
 -          "%x16", "%x17", "%x30"
 +
 +      : "%x16", "%x17", /* Exclude %r18 (platform/temporary register) */
 +        "%x19", "%x20", "%x21", "%x22", "%x23", "%x24", "%x25",
 +        "%x26", "%x27", "%x28", /* Exclude %x29 (frame pointer) */
 +        "%x30",
 +        "%d8", "%d9", "%d10", "%d11", "%d12", "%d13", "%d14"
 +
 +
      );
      return r;
  }
 }}}

 The stage2 compiler still segfaults, but comparing the `inplace/bin/ghc-
 stage2 +RTS -Da` output showed that with the above patch the program got a
 lot further before segfaulting.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10383#comment:11>
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