[GHC] #8308: Resurrect ticky code for counting constructor arity

[GHC]

#8308: Resurrect ticky code for counting constructor arity
------------------------------+--------------------------------------------
        Reporter:  jstolarek  |                Owner:
            Type:  task       |               Status:  patch
        Priority:  normal     |            Milestone:  8.2.1
       Component:  Profiling  |              Version:  7.7
      Resolution:             |             Keywords:  newcomer
Operating System:  Windows    |         Architecture:  Unknown/Multiple
 Type of failure:  Other      |            Test Case:
      Blocked By:             |             Blocking:
 Related Tickets:             |  Differential Rev(s):  Phab:D931 Phab:D2318
       Wiki Page:             |
------------------------------+--------------------------------------------

Comment (by Tamar Christina <tamar@…>):

 In [changeset:"b020db2a841c397a02ec352f8b6dc110b38b927b/ghc" b020db2/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="b020db2a841c397a02ec352f8b6dc110b38b927b"
 Fix Ticky histogram on Windows

 Summary:
 The histogram types are defined in `Ticky.c` as `StgInt` values.

 ```
 EXTERN StgInt RET_NEW_hst[TICKY_BIN_COUNT] INIT({0});
 EXTERN StgInt RET_OLD_hst[TICKY_BIN_COUNT] INIT({0});
 EXTERN StgInt RET_UNBOXED_TUP_hst[TICKY_BIN_COUNT] INIT({0});
 ```

 which means they'll be `32-bits` on `x86` and `64-bits` on `x86_64`.

 However the `bumpHistogram` in `StgCmmTicky` is incrementing them as if
 they're a `cLong`. A long on Windows `x86_64` is `32-bit`.

 As such when then value for the `_hst_1` is being set what it's actually
 doing
 is setting the value of the high bits of the first entry.

 This ends up giving us `0b‭100000000000000000000000000000000‬` or
 `4294967296`
 as is displayed in the ticket on #8308.

 Since `StgInt` is defined using the `WORD` size. Just use that directly in
 `bumpHistogram`.

 Also since `cLong` is no longer used after this commit it will also be
 dropped.

 Test Plan: make TEST=T8308

 Reviewers: mlen, jstolarek, bgamari, thomie, goldfire, simonmar, austin

 Reviewed By: bgamari, thomie

 Subscribers: #ghc_windows_task_force

 Differential Revision: https://phabricator.haskell.org/D2318

 GHC Trac Issues: #8308
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8308#comment:19>
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