GHC Weekly News - 10/24/2014

Austin Seipp austin at
Sat Oct 25 00:00:50 UTC 2014

Note: this post is available (with full hyperlinks) at


Hi *,

Welcome to the weekly GHC news. This one will be short this week, as
the preceding one occurred only on Monday - but we'll be going with
Fridays from now on, so next week we'll hopefully see a longer list.

 - GHC 7.8.4 tickets have been in waiting, and the RC will be soon
after Austin finishes some final merges and tests on his branch. **We
have not committed a time for the release after the RC**, yet we would
like people to **please seriously test** and immediately report any
major showstoppers - or alert us of ones we missed.
 - For the GHC 7.10 release, one of the major features we planned to
try and merge was DWARF debugging information. This is actually a
small component of larger ongoing work, including adding stack traces
to Haskell executables. While, unfortunately, not all the work can be
merged, we talked with Peter, and made a plan: our hope is to get
Phab:D169 merged, which lays all the groundwork, followed by DWARF
debugging information in the code generators. This will allow tools
like `gdb` or other extensible debuggers to analyze C-- IR accurately
for compiled executables.
 Peter has written up a wiki page, available at SourceNotes,
describing the design. We hope to land all the core infrastructure in
Phab:D169 soon, followed by DWARF information for the Native Code
Generator, all for 7.10.1
 - This past week, a discussion sort of organically started on the
`#ghc` IRC channel about the future of the LLVM backend. GHC's backend
is buggy, has no control over LLVM versions, and breaks frequently
with new versions. This all significantly impacts users, and relegates
the backend to a second class citizen. After some discussion, Austin
wrote up a proposal for a improved backend, and wrangled several other
people to help. The current plan is to try an execute this by GHC
7.12, with the goal of making the LLVM backend Tier 1 for major
supported platforms.
 - You may notice is now responds slightly
faster in some cases - we've activated a caching layer (CloudFlare) on
the site, so hopefully things should be a little more smooth.

Closed tickets this week: #9684, #9692, #9038, #9679, #9537, #1473.


Austin Seipp, Haskell Consultant
Well-Typed LLP,

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