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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Simon Peyton Jones pushed to branch wip/T25281 at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
Commits:
</h4>
<ul>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/68e2da5a9ed2f0221b0b17a19032d909a1ea1037">68e2da5a</a></strong>
<div>
<span> by Rodrigo Mesquita </span> <i> at 2024-10-05T10:36:15-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Deprecation for WarnCompatUnqualifiedImports
Fixes #25330
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4327f0e8c5091dae9ab0f58e2e3c8af5bacd12ea">4327f0e8</a></strong>
<div>
<span> by Andrew Lelechenko </span> <i> at 2024-10-05T10:36:52-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Restrict Data.List.NonEmpty.unzip to NonEmpty (a, b) -> (NonEmpty a, NonEmpty b)
Implementing the final phase of CLC proposal https://github.com/haskell/core-libraries-committee/issues/86
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ceca9efb3d437fb74263877d98d4fb4a45ee96b8">ceca9efb</a></strong>
<div>
<span> by Cheng Shao </span> <i> at 2024-10-06T02:18:31+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>driver: fix runWorkerLimit on wasm
This commit fixes link-time unresolved symbol errors for sem_open etc
on wasm, by making runWorkerLimit always behave single-threaded. This
avoids introducing the jobserver logic into the final wasm module and
thus avoids referencing the posix semaphore symbols.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/135fd1ac9212ba7d3517e4e4c0bf85bf247ac3b3">135fd1ac</a></strong>
<div>
<span> by Torsten Schmits </span> <i> at 2024-10-06T02:18:31+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Parallelize getRootSummary computations in dep analysis downsweep
This reuses the upsweep step's infrastructure to process batches of
modules in parallel.
I benchmarked this by running `ghc -M` on two sets of 10,000 modules;
one with a linear dependency chain and the other with a binary tree.
Comparing different values for the number of modules per thread
suggested an optimum at `length targets `div` (n_cap * 2)`, with results
similar to this one (6 cores, 12 threads):
```
Benchmark 1: linear 1 jobs
Time (mean ± σ): 1.775 s ± 0.026 s [User: 1.377 s, System: 0.399 s]
Range (min … max): 1.757 s … 1.793 s 2 runs
Benchmark 2: linear 6 jobs
Time (mean ± σ): 876.2 ms ± 20.9 ms [User: 1833.2 ms, System: 518.6 ms]
Range (min … max): 856.2 ms … 898.0 ms 3 runs
Benchmark 3: linear 12 jobs
Time (mean ± σ): 793.5 ms ± 23.2 ms [User: 2318.9 ms, System: 718.6 ms]
Range (min … max): 771.9 ms … 818.0 ms 3 runs
```
Results don't differ much when the batch size is reduced to a quarter
of that, but there's significant thread scheduling overhead for a size
of 1:
```
Benchmark 1: linear 1 jobs
Time (mean ± σ): 2.611 s ± 0.029 s [User: 2.851 s, System: 0.783 s]
Range (min … max): 2.591 s … 2.632 s 2 runs
Benchmark 2: linear 6 jobs
Time (mean ± σ): 1.189 s ± 0.007 s [User: 2.707 s, System: 1.103 s]
Range (min … max): 1.184 s … 1.194 s 2 runs
Benchmark 3: linear 12 jobs
Time (mean ± σ): 1.097 s ± 0.006 s [User: 2.938 s, System: 1.300 s]
Range (min … max): 1.093 s … 1.101 s 2 runs
```
Larger batches also slightly worsen performance.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/535a2117239f0d0e4588c6616fcd8deed725cfc0">535a2117</a></strong>
<div>
<span> by Daniel Díaz </span> <i> at 2024-10-06T09:51:46-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Clarify the meaning of "exactly once" in LinearTypes
Solves documentaion issue #25084.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/92f8939a5fa689dc0143501cfeac0b3b2cd7abd6">92f8939a</a></strong>
<div>
<span> by Krzysztof Gogolewski </span> <i> at 2024-10-06T09:52:22-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Only allow (a => b) :: Constraint rather than CONSTRAINT rep
Fixes #25243
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/19bd6a1f65875dac771388f3a0b96b71acfca37e">19bd6a1f</a></strong>
<div>
<span> by Sebastian Graf </span> <i> at 2024-10-07T08:34:07+01:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Desugaring, plus -Wincomplete-record-selectors
This commit does several related things:
* Major refactor of the handling of applications in the desugarer.
Now all applications are handled in `dsApp`, `ds_app` and related
functions. This dramatically simplifies the code and removes
complicated cruft that had accumulated. Hooray.
Fixes #25281.
* Improve the handling of -Wincomplete-record-selectors.
We now incorporate the result type of unsaturated record selector
applications as well as consider long-distance information in
getField applications.
Plus, the implmentation now builds the improved `dsApp` stuff
above, so it is much easier to understand.
Plus, incorporates improved error message wording suggested
by Adam Gundry in !12685.
Fixes #24824, #24891
See the long Note [Detecting incomplete record selectors]
* Add -Wincomplete-record-selectors to -Wall, as specified in
GHC Proposal 516.
To do this, I also had to add -Wno-incomplete-record-selectors
to the build flags for Cabal in GHC's CI. See
hadrian/src/Settings/Warnings.hs. We can remove this when
Cabal is updated so that it doesn't trigger the warning:
https://github.com/haskell/cabal/issues/10402
2.6% decrease in compile time allocation in RecordUpPerf
Metric Decrease:
RecordUpdPerf
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5b5b6cc2f6a1d34d7f3be33f8c09a69a39000850">5b5b6cc2</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-10-07T08:34:07+01:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Elmininate incomplete record selectors
This patch is a pure refactor of GHC's source code, to avoid the use
of partial record selectors. It was provoked by adding
-Wincomplete-record-selectors to -Wall (as the GHC Proposal specified),
which in turn showed up lots of places where GHC was using incomplete
record selectors.
This patch does mostly-simple refactoring to make it clear to the pattern
match checker that there is in fact no partiality.
There is one externally-visible change: I changed the data type HoleFit
to split out the two cases
data HoleFit = TcHoleFit TcHoleFit | RawHoleFit SDoc
data TcHoleFit = HoleFit { ...lots of fields }
There are large swathes of code that just deal with `TcHoleFit`, and
having it as a separate data types makes it apparent that `RawHoleFit`
can't occur.
This makes it much better -- but the change is visible in the
HolePlugin interface. I decided that there are so few clients of this
API that it's worth the change.
I moved several functions from Language.Haskell.Syntax to GHC.Hs.
Reason, when instantiated at (GhcPass _), the extension data construtcor
is guaranteed unused, and that justifies omitted patterns in these
functions. By putting them in GHC.Hs.X I can specialise the type for
(GhcPass _) and thereby make the function total.
An interesting side-light is that there were a few local function
definitions without a type signature, like this one in GHC.Parser.Header
convImport (L _ i) = (ideclPkgQual i, reLoc $ ideclName i)
This is fully closed, and so is generalised; but that generalises
it to any old pass, not (GhcPass _), so GHC rightly complains about the
use of the selector `ideclPkgQual`. I added a type signature to `i`, thus
convImport (L _ (i::ImportDecl GhcPs))
= (ideclPkgQual i, reLoc $ ideclName i)
which specialised the function enough to make the record selector complete.
Quite a surprising consequence of local let-generalisation!
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4e69c01ea96e4ba516e880a4451a4d6204069e51">4e69c01e</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-10-07T08:34:07+01:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Yet more
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/0614c06192a7a2d4949cbcac19db59b8d18f1407">0614c061</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-10-07T08:34:07+01:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>One more
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cabe5e38f4ef96f3823ff067b374ea5ddee120d8">cabe5e38</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-10-07T08:34:07+01:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>More
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/c43bf0aaed81c6a9b5d370f5ae7ddde86fe644ae">c43bf0aa</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2024-10-07T10:17:40+01:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #28272d; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>More
</pre>
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30 changed files:
</h4>
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<a href="#3008b031dfff6e38be4d7b8861e17927ee8c3fab">
compiler/GHC/CmmToAsm/Dwarf/Types.hs
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<a href="#23fa440e58d1f384d18650b52802ad6d03891572">
compiler/GHC/CmmToAsm/Reg/Graph/Stats.hs
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<a href="#182d6a315e784018aa9c8b2ad736036b97bd5d48">
compiler/GHC/Core.hs
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<a href="#783e5dae6e86931f06700fc088fb7d48c8a07386">
compiler/GHC/Core/Coercion.hs
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<a href="#b452cc5181a4af3460c43a4e3e4b5edaa238b4e0">
compiler/GHC/Core/ConLike.hs
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compiler/GHC/Core/FVs.hs
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compiler/GHC/Core/LateCC/OverloadedCalls.hs
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compiler/GHC/Core/Lint.hs
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compiler/GHC/Core/Opt/Arity.hs
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compiler/GHC/Core/Opt/CprAnal.hs
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compiler/GHC/Core/Opt/DmdAnal.hs
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compiler/GHC/Core/Opt/Simplify/Env.hs
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compiler/GHC/Core/Opt/Simplify/Utils.hs
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compiler/GHC/Core/Opt/SpecConstr.hs
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compiler/GHC/Core/Rules.hs
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compiler/GHC/Core/SimpleOpt.hs
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compiler/GHC/Core/Subst.hs
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compiler/GHC/Core/Type.hs
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compiler/GHC/Core/Utils.hs
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compiler/GHC/CoreToIface.hs
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compiler/GHC/Driver/Flags.hs
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compiler/GHC/Driver/Make.hs
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compiler/GHC/Driver/Session.hs
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compiler/GHC/Hs/Binds.hs
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compiler/GHC/Hs/Decls.hs
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compiler/GHC/Hs/Expr.hs
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compiler/GHC/Hs/Pat.hs
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compiler/GHC/Hs/Stats.hs
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compiler/GHC/Hs/Type.hs
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