GHC update 28 (#84)

* GHC update 28 * Update 2024-05-02-ghc-update-28.md * jeff: add perf chapter link * Update 2024-05-02-ghc-update-28.md * Update 2024-05-02-ghc-update-28.md add profiling functionality work * Update 2024-05-02-ghc-update-28.md --------- Co-authored-by: Jeffrey Young <jeffrey.young@iohk.io> Co-authored-by: Luite Stegeman <stegeman@gmail.com>
input-output-hk · May 6, 2024 · 419c957 · 419c957
1 parent 1d1e8b9
commit 419c957
Showing 1 changed file with 52 additions and 0 deletions.
diff --git a/blog/2024-05-02-ghc-update-28.md b/blog/2024-05-02-ghc-update-28.md
@@ -0,0 +1,52 @@
+---
+slug: 2024-05-02-ghc-update
+title: "IOG GHC Update #28"
+authors: [sylvain,doyougnu,luite]
+tags: [ghc,ghc-update]
+---
+
+Triweekly update from the GHC DevX team at IOG.
+
+<!-- truncate -->
+
+Previous updates can be found [here](https://engineering.iog.io/tags/ghc-update).
+
+- Sylvain: completed and merged someone's patch opened for 4 years to make GHC
+  generate better LLVM IR for complete switches.
+  [GHC#24717](https://gitlab.haskell.org/ghc/ghc/-/issues/24717),
+  [GHC!12491](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12491).
+
+- Sylvain: fixed issue with code using DeriveLift and when building
+  template-haskell.
+  [GHC#22229](https://gitlab.haskell.org/ghc/ghc/-/issues/22229),
+  [GHC!12456](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12456).
+
+- Sylvain: fixed a segfault in GHCi when using breakpoints.
+  [GHC#24712](https://gitlab.haskell.org/ghc/ghc/-/issues/24712),
+  [GHC!12500](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12500)
+
+- Sylvain: fixed a JS codegen issue because GHC generates code that computes
+  with RUBBISH literals. There may be more to it as it's not really supposed to
+  happen, but at least the generated JS code is valid code now .
+  [GHC#24664](https://gitlab.haskell.org/ghc/ghc/-/issues/24664),
+  [GHC!12463](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12463).
+
+- Jeff: After a long exhausting battle with the GHC testsuite, jeff expanded the testsuite capabilites to track binary sizes for each backend in GHC's CI and their dependencies. [MR](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12372#c591f85f122007bac88228c5ff6fd76b40e6a811) is merging now.
+
+- Jeff: Published the [perf](https://haskell.foundation/hs-opt-handbook.github.io/src/Measurement_Observation/Binary_Profiling/linux_perf.html#perf-chapter) chapter for the [Haskell Optimization Handbook](https://github.com/haskellfoundation/hs-opt-handbook.github.io).
+
+- Hamish: added support for the JS backend in Miso
+  [Miso#738](https://github.com/dmjio/miso/pull/738). This led to a discussion
+  about generated code size. Sylvain opened two issues about ideas to reduce
+  code size ([GHC#24743](https://gitlab.haskell.org/ghc/ghc/-/issues/24743) and
+  [GHC#24744](https://gitlab.haskell.org/ghc/ghc/-/issues/24744)) and one MR to
+  prepare for #24743
+  [GHC!12538](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12538).
+
+- Luite: Made a new implementation of the functionality of starting/stopping
+  profiling counters for cost centre profiling [GHC!12478](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12478).
+  This implementation is simpler than the previous one [GHC!12440](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/12440),
+  but requires reading a global variable for each counter increment. Initial performance
+  measurements have shown that the cost is minor. We haven't merged this yet because of ongoing
+  work on even finer control of cost centre counters (multiple counters per cost centre stack and per-thread
+  settings), which might supersede this patch.