Shipping core libraries with debug symbols

[Peter Wortmann]

(sorry for late answer)

Yes, that's pretty much what this would boil down to. The patch is trivial:

https://github.com/scpmw/ghc/commit/29acc#diff-1

I think this is a good idea anyways. We can always re-introduce the data 
for higher -g<n> levels.

Greetings,
   Peter


On 05/01/2015 00:59, Johan Tibell wrote:
> What about keeping exactly what -g1 keeps for gcc (i.e. functions,
> external variables, and line number tables)?
>
> On Sun, Jan 4, 2015 at 5:48 PM, Peter Wortmann <scpmw at leeds.ac.uk
> <mailto:scpmw at leeds.ac.uk>> wrote:
>
>
>
>     Okay, I ran a little experiment - here's the size of the debug
>     sections that Fission would keep (for base library):
>
>        .debug_abbrev:          8932 - 0.06%
>        .debug_line:          374134 - 2.6%
>        .debug_frame:         671200 - 4.5%
>
>     Not that much. On the other hand, .debug_info is a significant
>     contributor:
>
>        .debug_info(full):   4527391 - 30%
>
>     Here's what this contains: All procs get a corresponding DWARF
>     entry, and we declare all Cmm blocks as "lexical blocks". The latter
>     isn't actually required right now - to my knowledge, GDB simply
>     ignores it, while LLDB shows it as "inlined" routines. In either
>     case, it just shows yet more GHC-generated names, so it's really
>     only useful for profiling tools that know Cmm block names.
>
>     So here's what we get if we strip out block information:
>
>        .debug_info(!block): 1688410 - 11%
>
>     This eliminates a good chunk of information, and might therefore be
>     a good idea for "-g1" at minimum. If we want this as default for
>     7.10, this would make the total overhead about 18%. Acceptable? I
>     can supply a patch if needed.
>
>     Just for comparison - for Fission we'd strip proc records as well,
>     which would cause even more extreme savings:
>
>        .debug_info(!proc):    36081 - 0.2%
>
>     At this point the overhead would be just about 7% - but without
>     doing Fission properly this would most certainly affect debuggers.
>
>     Greetings,
>        Peter
>
>     On 03/01/2015 21:22, Johan Tibell wrote:
>     > How much debug info (as a percentage) do we currently generate? Could we just keep it in there in the release?
>
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