GHC Weekly News - 2015/01/27

thoughtpolice - 2015-01-27

Hi *,

It’s time for some GHC Weekly news!

  • Austin took the time the past week to check ./validate --slow failures, and is planning on filing bugs and fixes for the remaining failures soon. Afterwords, we’ll immediately begin enabling --slow on Phabricator, so developers get their patches tested more thoroughly.

  • The 7.10 release looks like it will likely not have a 3rd Release Candidate, and will be released in late February of 2015, as we originally expected.

  • The 7.10 branch currently has two showstopping bugs we plan on hitting before the final release. And we’d really like for users to test so we can catch more!

  • Austin Seipp will likely be gone for the coming week in a trip to New York City from the 28th to the 4th, meaning (much to the dismay of cheering crowds) you’d better catch him beforehand if you need him! (Alternatively Austin will be held back due to an intense snowstorm developing in NYC. So, we’ll see!)

  • Austin is planning on helping the LLVM support in HEAD soon; after coordinating with Ben Gamari, we’re hoping to ship GHC 7.12 with (at least) LLVM 3.6 as an officially supported backend, based on the documentation described in https://ghc.haskell.org/trac/ghc/wiki/ImprovedLLVMBackend - lots of thanks to Ben for working with upstream to file bugs and improve things!

And in other news, through chatter on the mailing list and Phabricator, we have:

  • Austin Seipp announced GHC 7.10.1 RC2: https://www.haskell.org/pipermail/ghc-devs/2015-January/008140.html

  • Peter Trommler posted his first version of a native Linux/PowerPC 64bit code generator! There’s still a lot more work to do, but this is a significantly improved situation over the unregisterised C backend. Curious developers can see the patch at Phab:D629.

  • A long, ongoing thread started by Richard Eisenberg about the long-term plans for the vectorisation code have been posted. The worry is that the vectoriser as well as DPH have stagnated in development, which costs other developers any time they need to build GHC, make larger changes, or keep code clean. There have been a lot of varied proposals in the thread from removing the code to commenting it out, to keeping it. It’s unclear what the future holds, but the discussion still rages on. https://www.haskell.org/pipermail/ghc-devs/2015-January/007986.html

  • Karel Gardas is working on reviving the SPARC native code generator, but has hit a snag where double float load instructions were broken. https://www.haskell.org/pipermail/ghc-devs/2015-January/008123.html

  • Alexander Vershilov made a proposal to the GHC team: can we remove the transformers dependency? It turns out to be a rather painful dependency for users of the GHC API and of packages depending on transformers, as you cannot link against any version other than the one GHC ships, causing pain. The alternative proposal involves splitting off the transformers dependency into a package of Orphan instances. The final decision isn’t yet clear, nor is a winner in clear sight yet! https://www.haskell.org/pipermail/ghc-devs/2015-January/008058.html

  • Konstantine Rybnikov has a simple question about GHC’s error messages: can they say Error: before anything else, to be more consistent with warnings? It seems like a positive change - and it looks like Konstantine is on the job to fix it, too. https://www.haskell.org/pipermail/ghc-devs/2015-January/008105.html

  • Simon Marlow has started a long thread about the fate of records in future GHC versions. Previously, Adam Gundry had worked on OverloadedRecordFields. And now Nikita Volkov has introduced his records library which sits in a slightly different spot in the design space. But now the question is - how do we proceed? Despite all prior historical precedent, it looks like there’s finally some convergence on a reasonable design that can hit GHC in the future. https://www.haskell.org/pipermail/ghc-devs/2015-January/008049.html

Closed tickets the past two weeks include: #9889, #9384, #8624, #9922, #9878, #9999, #9957, #7298, #9836, #10008, #9856, #9975, #10013, #9949, #9953, #9856, #9955, #9867, #10015, #9961, #5364, #9928, and #10028.