[GHC] #11353: DWARF call frame information incorrect in the presence of unsafe foreign calls

[GHC]

#11353: DWARF call frame information incorrect in the presence of unsafe foreign
calls
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        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  7.10.3
  (CodeGen)                          |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Debugging         |  (amd64)
  information is incorrect           |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11338, #11337    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by scpmw):

 Not sure why you are worrying about the order - that gets derived from the
 NCG output using cmmDebugLink. This is precisely so NCG is free to do
 whatever it wants with blocks, even reorder or optimise them out.

 My first impulse here would be that you will need some sort of `UNWIND`
 anyway to have NCG create labels. So maybe have it carry its unwind rules,
 that would allow NCG to update it. In either case, you would feed that
 information back roughly the same way that currently `ngs_labels` gets
 threaded back to debug information generation. As `UNWIND` would carry
 unique labels, this could just be replacing the current `[Label]` block
 list with an an ordered `[(Label, [UnwindTable])]` debug label to unwind
 table map.

 Not sure - this is exactly the kind of complexity that I tried my best to
 avoid, so I haven't put a lot of thought into it.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11353#comment:7>
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