[GHC] #14999: unwinding info for stg_catch_frame is wrong

[GHC]

#14999: unwinding info for stg_catch_frame is wrong
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        Reporter:  niteria           |                Owner:  niteria
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.4.3
       Component:  Compiler          |              Version:
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  Debugging         |  (amd64)
  information is incorrect           |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  phab:D4606
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"6132d7c5e6404936ef281a6f3be333fea780906e/ghc"
 6132d7c5/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="6132d7c5e6404936ef281a6f3be333fea780906e"
 Correctly add unwinding info in manifestSp and makeFixupBlocks

 In `manifestSp` the unwind info was before the relevant instruction, not
 after.  I added some notes to establish semantics.  Also removes
 redundant annotation in stg_catch_frame.

 For `makeFixupBlocks` it looks like we were off by `wORD_SIZE dflags`.
 I'm not sure why, but it lines up with `manifestSp`.  In fact it lines
 up so well so that I can consolidate the Sp unwind logic in
 `maybeAddUnwind`.  I detected the problems with `makeFixupBlocks` by
 running T14779b after patching D4559.

 Test Plan: added a new test

 Reviewers: bgamari, scpmw, simonmar, erikd

 Reviewed By: bgamari

 Subscribers: thomie, carter

 GHC Trac Issues: #14999

 Differential Revision: https://phabricator.haskell.org/D4606
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14999#comment:5>
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