GHC status report

[Edward Kmett]

On Thu, May 1, 2014 at 5:30 PM, Simon Marlow <marlowsd at gmail.com> wrote:

> We should fix this (or at least make it a lot less likely).  Is there a
> ticket?
>

Not yet. I just converted to 7.8.2 the other day (I'd been running the
release candidate) and wanted to duplicate the problem first. I haven't
been writing code on my larger projects since upgrading, so I've yet to
experience the problem again.

A similar issue was happening with parallel rebuilds with -j on a Mac after
^C'ing out of a cabal build, when compiling with -dynamic-too, where it
winds up blaming missing files, but can't generate them That has caused me
to abandon using -j during development. I encountered this one first, and
I'm not sure if these are both just the same error.

If I had to guess part of the problem seems like the logic in cabal and/or
ghc around -dynamic-too treats the .dyn_foo and the .foo files as one
inseparable artifact, when you can actually wind up with one of them and
not the other.

A final dynamic-linking issue that is only tangentially related is that it
seems the dynamic-only code path is a bit broken as well. e.g. shared:
True, executable-dynamic: True in cabal. I've had it complain about about
looking for missing installed .hi files and skip right past the .dyn_hi
files when working on a subsequent package that uses the first one.

The only real relevance of that issue is that I was hoping to use it to cut
my build times and to address the above concerns by not having two
artifacts being produced when the tooling is designed around one, but I
seem forced to build both.

As soon as I have a build break in a way that I can show a decent trace,
I'll put in a ticket.

-Edward


> Cheers,
> Simon
>
>
>  -Edward
>>
>>
>> On Thu, May 1, 2014 at 3:29 AM, Simon Peyton Jones
>> <simonpj at microsoft.com <mailto:simonpj at microsoft.com>> wrote:
>>
>>     | Dynamic linking has been a huge headache in GHC, and it's not
>>     clear that
>>     | it's an overall improvement compared with the static linker.  Now
>> that
>>     | 7.8 is out of the way, it's time to have a conversation about
>>     whether we
>>     | want to do dynamic linking again for 7.10, or revert to static
>>     linking.
>>
>>     I echo this. Dynamic linking has had many un-anticipated costs and
>>     it is still very far from sorted out.  It originally felt like a
>>     Fantastic Idea to give up our own linker and adopt the system
>>     linker, but it now feels to me like a black hole, endlessly sucking
>>     effort and increasing complexity.
>>
>>     My viewpoint is highly un-informed about details; I just watch the
>>     traffic going by.  And of course it does have benefits that
>>     doubtless generate less traffic.
>>
>>     Simon
>>
>>     |
>>     |
>>     |
>>     | >
>>     | > On Tue, Apr 29, 2014 at 6:13 PM, Simon Peyton Jones
>>     | > <simonpj at microsoft.com <mailto:simonpj at microsoft.com>
>>     <mailto:simonpj at microsoft.com <mailto:simonpj at microsoft.com>>> wrote:
>>     | >
>>     | >     As Austin has told us, there's a draft of the *GHC Status
>> Report
>>     | for
>>     | >     the HCAR*, here:____
>>     | >
>>     | > https://ghc.haskell.org/trac/ghc/wiki/Status/May14____
>>     | >
>>     | >     Have we missed out something  you have been working hard on?
>>  Do
>>     | >     take a moment to add a bullet in an appropriate place (it's a
>>     | >     wiki).  I'd like to be sure that we are giving credit to all
>> the
>>     | >     appropriate people, so please help us fix that too.  GHC is
>>     a team
>>     | >     effort.____
>>     | >
>>     | >     Deadline is 1 May I think.____
>>     | >
>>     | >     Thanks____
>>     | >
>>     | >     Simon____
>>     | >
>>     | >     __ __
>>     | >
>>     | >
>>     | >     _______________________________________________
>>     | >     ghc-devs mailing list
>>     | > ghc-devs at haskell.org <mailto:ghc-devs at haskell.org>
>>     <mailto:ghc-devs at haskell.org <mailto:ghc-devs at haskell.org>>
>>
>>     | > http://www.haskell.org/mailman/listinfo/ghc-devs
>>     | >
>>     | >
>>     | >
>>     | >
>>     | > _______________________________________________
>>     | > ghc-devs mailing list
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>>     | > http://www.haskell.org/mailman/listinfo/ghc-devs
>>     | >
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>>
>
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