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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Zubin pushed to branch wip/24275 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: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8bef8d9ff72ca826338e2e893b0d97bfc7b25d0b">8bef8d9f</a></strong>
<div>
<span> by Luite Stegeman </span> <i> at 2023-12-14T04:31:33-05:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>JS: Mark spurious CI failures js_fragile(24259)
This marks the spurious test failures on the JS platform as
js_fragile(24259), so we don't hold up merge requests while
fixing the underlying issues.
See #24259
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/1c79526a0ee0060dc692478926f6d0228c853a33">1c79526a</a></strong>
<div>
<span> by Finley McIlwaine </span> <i> at 2023-12-15T12:24:40-08:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Late plugins
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/000c3302c6520430ca4c702d55d8eaeec61c9997">000c3302</a></strong>
<div>
<span> by Finley McIlwaine </span> <i> at 2023-12-15T12:24:40-08:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>withTiming on LateCCs and late plugins
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/be4551acf4ed705a1c3384db6a537f61000da688">be4551ac</a></strong>
<div>
<span> by Finley McIlwaine </span> <i> at 2023-12-15T12:24:40-08:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>add test for late plugins
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7c29da9f2650e6b849d50efbbe1ac82b4f52f8fc">7c29da9f</a></strong>
<div>
<span> by Finley McIlwaine </span> <i> at 2023-12-15T12:24:40-08:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Document late plugins
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9a52ae46a33b490161e1e3e1cc70caa46c60488a">9a52ae46</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-12-20T07:07:26-05:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>Fix thunk update ordering
Previously we attempted to ensure soundness of concurrent thunk update
by synchronizing on the access of the thunk's info table pointer field.
This was believed to be sufficient since the indirectee (which may
expose a closure allocated by another core) would not be examined
until the info table pointer update is complete.
However, it turns out that this can result in data races in the presence
of multiple threads racing a update a single thunk. For instance,
consider this interleaving under the old scheme:
Thread A Thread B
--------- ---------
t=0 Enter t
1 Push update frame
2 Begin evaluation
4 Pause thread
5 t.indirectee=tso
6 Release t.info=BLACKHOLE
7 ... (e.g. GC)
8 Resume thread
9 Finish evaluation
10 Relaxed t.indirectee=x
11 Load t.info
12 Acquire fence
13 Inspect t.indirectee
14 Release t.info=BLACKHOLE
Here Thread A enters thunk `t` but is soon paused, resulting in `t`
being lazily blackholed at t=6. Then, at t=10 Thread A finishes
evaluation and updates `t.indirectee` with a relaxed store.
Meanwhile, Thread B enters the blackhole. Under the old scheme this
would introduce an acquire-fence but this would only synchronize with
Thread A at t=6. Consequently, the result of the evaluation, `x`, is not
visible to Thread B, introducing a data race.
We fix this by treating the `indirectee` field as we do all other
mutable fields. This means we must always access this field with
acquire-loads and release-stores.
See #23185.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f4b535382db3e7879dd4b9312ed64d6586339f1f">f4b53538</a></strong>
<div>
<span> by Vladislav Zavialov </span> <i> at 2023-12-20T07:08:02-05:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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;'>docs: Fix link to 051-ghc-base-libraries.rst
The proposal is no longer available at the previous URL.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8a8d964d555a1bd18a64617b62d61d537e28a0c9">8a8d964d</a></strong>
<div>
<span> by Zubin Duggal </span> <i> at 2023-12-20T17:53:22+05:30 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #333238; position: relative; font-family: var(--default-mono-font, "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: Really don't lose track of nodes when we fail to resolve cycles
This fixes a bug in 8db8d2fd1c881032b1b360c032b6d9d072c11723, where we could lose
track of acyclic components at the start of an unresolved cycle. We now ensure we
never loose track of any of these components.
As T24275 demonstrates, a "cyclic" SCC might not really be a true SCC:
When viewed without boot files, we have a single SCC
```
[REC main:T24275B [main:T24275B {-# SOURCE #-},
main:T24275A {-# SOURCE #-}]
main:T24275A [main:T24275A {-# SOURCE #-}]]
```
But with boot files this turns into
```
[NONREC main:T24275B {-# SOURCE #-} [],
REC main:T24275B [main:T24275B {-# SOURCE #-},
main:T24275A {-# SOURCE #-}]
main:T24275A {-# SOURCE #-} [main:T24275B],
NONREC main:T24275A [main:T24275A {-# SOURCE #-}]]
```
Note that this is truly not an SCC, as no nodes are reachable from T24275B.hs-boot.
However, we treat this entire group as a single "SCC" because it seems so when we
analyse the graph without taking boot files into account.
To handle this, I extended `findCycle` to not assume its input is an SCC, and to
try harder to find cycles in its input.
Fixes #24275
</pre>
</li>
</ul>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
30 changed files:
</h4>
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<a href="#f67efdd3ec0e6a124bc1f40bec7c1e910d36c06c">
compiler/GHC/Core/LateCC.hs
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<a href="#076d011643e7ccd7d4e01c8948db82d0d4f59432">
compiler/GHC/Data/Graph/Directed.hs
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<a href="#9a679a2680ef6061397f1987091ea9f96ffe095d">
compiler/GHC/Driver/Main.hs
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<a href="#1dab250036d04cfcf3530f6ff27889f723cc2dda">
compiler/GHC/Driver/Make.hs
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<a href="#c4236c3de9fb0253d53aab2fe6dbdd3a2aa8b8bc">
compiler/GHC/Driver/Plugins.hs
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<a href="#2f341f858154eb8e1900d5bd92a156b13ddd06f3">
compiler/GHC/StgToCmm/Bind.hs
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<a href="#523e258f899a29c551e69a88115587d32ba73db1">
docs/users_guide/9.10.1-notes.rst
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<a href="#616606d7ec92f17c847240a7bc125e1d8c9c00a1">
docs/users_guide/extending_ghc.rst
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<a href="#b817c80cbb15890d9a6df41e91d15d7442471f3c">
libraries/base/tests/all.T
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<a href="#c6ca7d2b8bb94ab0a0ee349206e12a4a65925cec">
rts/Apply.cmm
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rts/Compact.cmm
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<a href="#7cd911ebab0f9f45be4a3d53fd5b4cb6cf96de6b">
rts/Heap.c
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<a href="#539d43389593f2626a387f2c904f03c215c7c802">
rts/Interpreter.c
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rts/Messages.c
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rts/PrimOps.cmm
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rts/StableName.c
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rts/StgMiscClosures.cmm
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rts/ThreadPaused.c
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rts/Threads.c
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rts/Updates.cmm
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rts/Updates.h
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rts/include/Cmm.h
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rts/include/rts/TSANUtils.h
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rts/include/stg/SMP.h
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rts/sm/Evac.c
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rts/sm/NonMovingMark.c
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rts/sm/Storage.c
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<a href="#c591f85f122007bac88228c5ff6fd76b40e6a811">
testsuite/driver/testlib.py
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<a href="#a25d25da9535c7e8c81cd6701fe76ea4b81b74b1">
testsuite/tests/backpack/cabal/T20509/all.T
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<a href="#83920aed73deb4a4d473dbc760163216be638d67">
testsuite/tests/backpack/cabal/bkpcabal02/all.T
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The diff was not included because it is too large.
</h5>
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