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<h3>
Ben Gamari pushed to branch wip/unloading
at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4>
Commits:
</h4>
<ul>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b9d4dd9cbc4f1dd40e6beaf5d8301ac9d3034fca">b9d4dd9c</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:44:17-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">SMP.h: Add C11-style atomic operations
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ccf2d4b091284a60acc6c16d166ea7cafade209f">ccf2d4b0</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Infrastructure for testing with ThreadSanitizer
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/a61f66d6c14762869ad95b7646bce975df9f80f8">a61f66d6</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/CNF: Initialize all bdescrs in group
It seems wise and cheap to ensure that the whole bdescr of all blocks of
a compact group is valid, even if most cases only look at the flags
field.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/65136c134d1b6e2f2c5d7193fade3c99a8cb81c4">65136c13</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Capability: Intialize interrupt field
Previously this was left uninitialized.
Also clarify some comments.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b3ce6acaae1b386aeca6649738cf286ad71ed5cd">b3ce6aca</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Task: Make comments proper Notes
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d3890ac737e282a582f0cc9819dedd2a8c363501">d3890ac7</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/SpinLock: Move to proper atomics
This is fairly straightforward; we just needed to use relaxed operations
for the PROF_SPIN counters and a release store instead of a write
barrier.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ef88712f5dcc9e245b4e3819be1889e659731b59">ef88712f</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/OSThreads: Fix data race
Previously we would race on the cached processor count. Avoiding this is
straightforward; just use relaxed operations.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/33a719c392be4d8a389a1331c6c88093148f7396">33a719c3</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/ClosureMaros: Use relaxed atomics
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f08951fd0279248bd4e9536e4cf44ba658aaf710">f08951fd</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">configure: Bump minimum-supported gcc version to 4.7
Since the __atomic_* builtins are not supported until gcc 4.7. Given
that this version was released in 2012 I think this is acceptable.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d584923a1e1fe92a4bb38b2cd1f0bf5a3b7802f0">d584923a</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Fix thread leak in hs_try_putmvar00[13]
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bf1b0bc78da7dbe5f6fbda54b37a9cb165ff857f">bf1b0bc7</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T20:59:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Introduce SET_HDR_RELEASE
Also ensure that we also store the info table pointer last to ensure
that the synchronization covers all stores.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/1a2e9f5e8f125ea47b1d6d2a1740614109488c24">1a2e9f5e</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">gitlab-ci: Add nightly-x86_64-linux-deb9-tsan job
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/58a5b0e55dfb7bbb95f51ade650b1d45dc2d929c">58a5b0e5</a></strong>
<div>
<span>by GHC GitLab CI</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Mark setnumcapabilities001 as broken with TSAN
Due to #18808.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d9bc7dea72e0135cd0e969e8b4e977a33cbec906">d9bc7dea</a></strong>
<div>
<span>by GHC GitLab CI</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Skip divbyzero and derefnull under TSAN
ThreadSanitizer changes the output of these tests.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/fcc42a10ada33f2ad6c344fdd8f8468742bf35cd">fcc42a10</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Skip high memory usage tests with TSAN
ThreadSanitizer significantly increases the memory footprint of tests,
so much so that it can send machines into OOM.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cae4bb3e0f65016be057db2f1b02f449ba646e74">cae4bb3e</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Mark hie002 as high_memory_usage
This test has a peak residency of 1GByte; this is large enough to
classify as "high" in my book.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/dae1b86abc7c22ae92eba264709546783ac4673f">dae1b86a</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Mark T9872[abc] as high_memory_usage
These all have a maximum residency of over 2 GB.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/c5a0bb22238a437ae050e8cc6120d5a41533866d">c5a0bb22</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">gitlab-ci: Disable documentation in TSAN build
Haddock chews through enough memory to cause the CI builders to OOM and
there's frankly no reason to build documentation in this job anyways.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4cb1232ec5ad92f40ed494fde4a9f172cc4980fb">4cb1232e</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">TSANUtils: Ensure that C11 atomics are supported
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7ed15f7f84f43729fd8373b8c6fdd07ede07d05e">7ed15f7f</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Mark T3807 as broken with TSAN
Due to #18883.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f7e6f012bcedbf60fac2631e223b8766c9afa959">f7e6f012</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Mark T13702 as broken with TSAN due to #18884
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/16b136b0c3c79833a1e35305f9c5d1b0511eda9c">16b136b0</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:36-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Factor out logic to identify a good capability for running a task
Not only does this make the control flow a bit clearer but it also
allows us to add a TSAN suppression on this logic, which requires
(harmless) data races.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2781d68c5d94fd87435d6316c2d4118171e97b14">2781d68c</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:36-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Annotate benign race in waitForCapability
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f6b4b492d9c112c30ddc0bda2338b143b56faf4c">f6b4b492</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:36-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Clarify locking behavior of releaseCapability_
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/65219810a41f1c903838185a766baeba8954cc88">65219810</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:36-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Add assertions for task ownership of capabilities
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/31fa87ecb4ff1abc761d776d48e87cd0fd37bedd">31fa87ec</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:36-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Use relaxed atomics on n_returning_tasks
This mitigates the warning of a benign race on n_returning_tasks in
shouldYieldCapability.
See #17261.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/6517a2ea285688907e8d71e8313f04e919a24445">6517a2ea</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:36-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Mitigate races in capability interruption logic
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2e9ba3f2881a59fde9932929dce7c42cdcfd4432">2e9ba3f2</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:36-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Capability: Use relaxed operations for last_free_capability
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/e10dde371229d45bcc864207cfb6e022dde51bf9">e10dde37</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:37-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Use relaxed operations for cap->running_task (TODO)
This shouldn't be necessary since only the owning thread of the capability
should be touching this.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/855325cdcad4c10e0f37c10934a62a07c6ec48b2">855325cd</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:37-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Schedule: Use relaxed operations for sched_state
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/811f915db3b682f33aad2c3e6ca039a6e8451c69">811f915d</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:37-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Accept data race in work-stealing implementation
This race is okay since the task is owned by the capability pushing it.
By Note [Ownership of Task] this means that the capability is free to
write to `task->cap` without taking `task->lock`.
Fixes #17276.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8d2b3c3d1fcb9009b6dfcce85777e04bcec9d219">8d2b3c3d</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:37-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Eliminate data races on pending_sync
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f88710185acc0e02b334b96004f4b8fae38c5eb9">f8871018</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:37-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Schedule: Eliminate data races on recent_activity
We cannot safely use relaxed atomics here.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d079b9435382882b0b069ea40bcd287db18082d3">d079b943</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:37-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Avoid data races in message handling
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/06f80497b8bd5eea93b72989e9b58372ef482ef9">06f80497</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:37-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Messages: Drop incredibly fishy write barrier
executeMessage previously had a write barrier at the beginning of its
loop apparently in an attempt to synchronize with another thread's
writes to the Message. I would guess that the author had intended to use
a load barrier here given that there are no globally-visible writes done
in executeMessage.
I've removed the redundant barrier since the necessary load barrier is
now provided by the ACQUIRE_LOAD.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d4a87779dc691a4db876817e01ba237655768d77">d4a87779</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:38-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/ThreadPaused: Avoid data races
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/56778ab38eeb9fd683250a57c228f3821a444811">56778ab3</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:38-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Schedule: Eliminate data races in run queue management
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/086521f744f989a4f11585989f1304ab1333a61b">086521f7</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:38-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Eliminate shutdown data race on task counters
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/abad977849a70578bca4e5b17a85aff43e3327be">abad9778</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:38-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Threads: Avoid data races (TODO)
Replace barriers with appropriate ordering. Drop redundant barrier in
tryWakeupThread (the RELEASE barrier will be provided by sendMessage's
mutex release).
We use relaxed operations on why_blocked and the stack although it's not
clear to me why this is necessary.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2f56be8a74f1f012f1756380ae111ec1327ddde0">2f56be8a</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Messages: Annotate benign race
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7c0cdab17dcf57702bb57e4b9f4136701a33a2e0">7c0cdab1</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/RaiseAsync: Synchronize what_next read
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/6cc2a8a578688e1f0542373d913bc4b171239157">6cc2a8a5</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Task: Move debugTrace to avoid data race
Specifically, we need to hold all_tasks_mutex to read taskCount.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bbaec97d1d3d9984736d5f6424785b1c95bd8312">bbaec97d</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Disable flawed assertion
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/dd175a926c0e9654cd6ac8d9d26b183540c87331">dd175a92</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:39-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Document schedulePushWork race
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/3416244b736b386f0bbf8369083f90110cd524a2">3416244b</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:40-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Capabiliity: Properly fix data race on n_returning_tasks
There is a real data race but can be made safe by using proper atomic
(but relaxed) accesses.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/dffd943207dd356a113ee8ff3e51227c2655a039">dffd9432</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:40-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Make write of to_cap->inbox atomic
This is necessary since emptyInbox may read from to_cap->inbox without
taking cap->lock.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/1f4cbc2942ad8b757a225b23c9f097f371ca490c">1f4cbc29</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:57-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/BlockAlloc: Use relaxed operations
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d0d07cffeded2b1d1b4ffed1f8b06eddc9f06600">d0d07cff</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:57-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Rework handling of mutlist scavenging statistics
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9e5c7f6de8e3d4cda0c07e0f210d9d5004fc6131">9e5c7f6d</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:57-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Avoid data races in StablePtr implementation
This fixes two potentially problematic data races in the StablePtr
implementation:
* We would fail to RELEASE the stable pointer table when enlarging it,
causing other cores to potentially see uninitialized memory.
* We would fail to ACQUIRE when dereferencing a stable pointer.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/316add6762aca4a01fbe71d264b0c65c11313929">316add67</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:57-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Storage: Use atomics
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5c23bc4cd6936840deeb398bbea06165952f17c2">5c23bc4c</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:58-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Updates: Use proper atomic operations
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/3d0f033c5109ae0131b81e6b9aaf2a04ebeba1f4">3d0f033c</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:00:58-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Weak: Eliminate data races
By taking all_tasks_mutex in stat_exit. Also better-document the fact
that the task statistics are protected by all_tasks_mutex.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/edb4b92b218cee5b309866f3d236da30c5621567">edb4b92b</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:01:18-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/WSDeque: Rewrite with proper atomics
After a few attempts at shoring up the previous implementation, I ended
up turning to the literature and now use the proven implementation,
> N.M. Lê, A. Pop, A.Cohen, and F.Z. Nardelli. "Correct and Efficient
> Work-Stealing for Weak Memory Models". PPoPP'13, February 2013,
> ACM 978-1-4503-1922/13/02.
Note only is this approach formally proven correct under C11 semantics
but it is also proved to be a bit faster in practice.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d39bbd3dbd569d60c7f27f68a1f30885a30c3fa3">d39bbd3d</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:01:33-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Use relaxed atomics for whitehole spin stats
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8f802f386ad5774a863f756f2d8d397903074700">8f802f38</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:01:33-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Avoid lock order inversion during fork
Fixes #17275.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cef667b081c71008e0633d276349dd863cb46d7f">cef667b0</a></strong>
<div>
<span>by GHC GitLab CI</span>
<i>at 2020-10-24T21:01:34-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Use proper relaxe operations in getCurrentThreadCPUTime
Here we are doing lazy initialization; it's okay if we do the check more
than once, hence relaxed operation is fine.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8cf50eb1b5f145d7bca9abae6220f4c2622e21b1">8cf50eb1</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:01:54-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/STM: Use atomics
This fixes a potentially harmful race where we failed to synchronize
before looking at a TVar's current_value.
Also did a bit of refactoring to avoid abstract over management of
max_commits.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/88a7ce3893fe16c7d345e91838722b18ad728740">88a7ce38</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:01:54-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/stm: Strengthen orderings to SEQ_CST instead of volatile
Previously the `current_value`, `first_watch_queue_entry`, and
`num_updates` fields of `StgTVar` were marked as `volatile` in an
attempt to provide strong ordering. Of course, this isn't sufficient.
We now use proper atomic operations. In most of these cases I strengthen
the ordering all the way to SEQ_CST although it's possible that some
could be weakened with some thought.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f97c59ce014687979fa731db7227773fa83d2156">f97c59ce</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:11-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Mitigate data races in event manager startup/shutdown
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/c7c3f8aa978dd6230e3b0f2d21dec84a47bd5e7c">c7c3f8aa</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:22-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Accept benign races in Proftimer
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5a98dfcae41b79bed912521d1eeb2cbc09f0742b">5a98dfca</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:22-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Pause timer while changing capability count
This avoids #17289.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/01d9552509a94d1bd1a717f1730b1c513bf7fea8">01d95525</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:22-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Fix #17289
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9a528985e8e738b4987b58938fad5711af81b61a">9a528985</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:23-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">suppress #17289 (ticker) race
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/1726ec419f3c537b28e1290424203c586408bd41">1726ec41</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:23-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Fix timer initialization
Previously `initScheduler` would attempt to pause the ticker and in so
doing acquire the ticker mutex. However, initTicker, which is
responsible for initializing said mutex, hadn't been called
yet.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bfbe4366e658035a9182500ae286c71fc1ee54fd">bfbe4366</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:23-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Fix races in Pthread timer backend shudown
We can generally be pretty relaxed in the barriers here since the timer
thread is a loop.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/297acc71dbbc0786c55c178d5e5fc453d9f4f2f9">297acc71</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-24T21:02:44-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Stats: Hide a few unused unnecessarily global functions
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/aad1f803471fff1f187b0a0784dc38a867379847">aad1f803</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-30T00:41:14-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/GC: Use atomics
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d0bc05178ba8a36a8c18158a488471d15fbf97d1">d0bc0517</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-30T00:41:14-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Use RELEASE ordering in unlockClosure
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d44f523208d32b599fa7e1260de32515d2ef9944">d44f5232</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-30T00:41:14-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Storage: Accept races on heap size counters
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4e4a73868488f83aa9d355d147e116408634c140">4e4a7386</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-30T00:41:14-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Join to concurrent mark thread during shutdown
Previously we would take all capabilities but fail to join on the thread
itself, potentially resulting in a leaked thread.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/a80cc8577774a744d684cd1f513e373405cd2f2b">a80cc857</a></strong>
<div>
<span>by GHC GitLab CI</span>
<i>at 2020-10-30T00:41:14-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Fix race in GC CPU time accounting
Ensure that the GC leader synchronizes with workers before calling
stat_endGC.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/105d43db7bb7f399be3e5474d207e330d1b2da5a">105d43db</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-30T14:02:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/SpinLock: Separate out slow path
Not only is this in general a good idea, but it turns out that GCC
unrolls the retry loop, resulting is massive code bloat in critical
parts of the RTS (e.g. `evacuate`).
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f7b45cde43f47f94b77411477aabdb56f8f63d66">f7b45cde</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-10-30T14:02:19-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Use relaxed ordering on spinlock counters
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bd4abdc953427e084e7ecba89db64860f6859822">bd4abdc9</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T01:10:31-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Add performance test for #18698
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/dfd27445308d1ed2df8826c2a045130e918e8192">dfd27445</a></strong>
<div>
<span>by Hécate</span>
<i>at 2020-11-01T01:11:09-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Add the proper HLint rules and remove redundant keywords from compiler
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ce1bb9959e2465db1c3880f3c532ae7e1be39b41">ce1bb995</a></strong>
<div>
<span>by Hécate</span>
<i>at 2020-11-01T08:52:08-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Fix a leak in `transpose`
This patch was authored by David Feuer <david.feuer@gmail.com>
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/e63db32c7eb089985a1a7279a0a886a32d70ac0e">e63db32c</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T08:52:44-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Scav: Use bd->gen_no instead of bd->gen->no
This potentially saves a cache miss per scavenge.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b1dda15324bf08dcd6265e066577c18d4f3f061d">b1dda153</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T12:58:36-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Stats: Protect with mutex
While on face value this seems a bit heavy, I think it's far better than
enforcing ordering on every access.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5c2e6bced838b7d7617af2bfb272889a9af16a76">5c2e6bce</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T12:58:36-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Tear down stats_mutex after exitHeapProfiling
Since the latter wants to call getRTSStats.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ef25aaa107ae099a2a9bd80d3130664334c69482">ef25aaa1</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:02:11-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Annotate hopefully "benign" races in freeGroup
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/3a18155331e07e53b9f3b1d987ed430066b17aa4">3a181553</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:02:18-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Strengthen ordering in releaseGCThreads
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/af474f6246036d4f904949af96c5c74fb8d1dbe0">af474f62</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:05:38-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Suppress data race due to close
This suppresses the other side of a race during shutdown.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b4686bff56377a583f0605b81fae290d3fee4c4a">b4686bff</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:09:59-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/ci' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b8e66e0eecdc58ec5fea0b2c9a9454d38858886c">b8e66e0e</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:10:01-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/storage' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/375512cfbb968ed0ffbdf33153b71fab4b707dce">375512cf</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:10:02-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/wsdeque' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/65ebf07e459733b9dfb51b02ac987411bd478841">65ebf07e</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:10:03-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/misc' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/55c375d0bc1c7b9f5476d2b074f5da3539386c93">55c375d0</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:10:04-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/stm' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/a9f75fe23b47358bda585e9af3e2b44da7817c37">a9f75fe2</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:10:06-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/event-mgr' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8325d6585bd1eb440456abcb05a638c44f2aee88">8325d658</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:10:24-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/timer' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/07e82ba52228580cfbd90ff031e657acbecc715b">07e82ba5</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-01T13:10:35-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge branch 'wip/tsan/stats' into wip/tsan/all
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4ce2f7d6e6a516173750b1d740f345e90992ffce">4ce2f7d6</a></strong>
<div>
<span>by GHC GitLab CI</span>
<i>at 2020-11-02T23:45:06-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">testsuite: Add --top flag to driver
This allows us to make `config.top` a proper Path. Previously it was a
str, which caused the Ghostscript detection logic to break.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/0b7722219ffdb109c3a8b034a8e112d18e6e4336">0b772221</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-02T23:45:42-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Document that ccall convention doesn't support varargs
We do not support foreign "C" imports of varargs functions. While this
works on amd64, in general the platform's calling convention may need
more type information that our Cmm representation can currently provide.
For instance, this is the case with Darwin's AArch64 calling convention.
Document this fact in the users guide and fix T5423 which makes use of a
disallowed foreign import.
Closes #18854.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/81006a06736c7300626f9d692a118b493b585cd5">81006a06</a></strong>
<div>
<span>by David Eichmann</span>
<i>at 2020-11-02T23:46:19-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">RtsAPI: pause and resume the RTS
The `rts_pause` and `rts_resume` functions have been added to `RtsAPI.h` and
allow an external process to completely pause and resume the RTS.
Co-authored-by: Sven Tennie <sven.tennie@gmail.com>
Co-authored-by: Matthew Pickering <matthewtpickering@gmail.com>
Co-authored-by: Ben Gamari <bgamari.foss@gmail.com>
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bfb1e272950169c17963adaf423890e47b908f4d">bfb1e272</a></strong>
<div>
<span>by Ryan Scott</span>
<i>at 2020-11-02T23:46:55-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Display results of GHC.Core.Lint.lint* functions consistently
Previously, the functions in `GHC.Core.Lint` used a patchwork of
different ways to display Core Lint errors:
* `lintPassResult` (which is the source of most Core Lint errors) renders
Core Lint errors with a distinctive banner (e.g.,
`*** Core Lint errors : in result of ... ***`) that sets them apart
from ordinary GHC error messages.
* `lintAxioms`, in contrast, uses a completely different code path that
displays Core Lint errors in a rather confusing manner. For example,
the program in #18770 would give these results:
```
Bug.hs:1:1: error:
Bug.hs:12:1: warning:
Non-*-like kind when *-like expected: RuntimeRep
when checking the body of forall: 'TupleRep '[r]
In the coercion axiom Bug.N:T :: []. Bug.T ~_R Any
Substitution: [TCvSubst
In scope: InScope {r}
Type env: [axl :-> r]
Co env: []]
|
1 | {-# LANGUAGE DataKinds #-}
| ^
```
* Further digging reveals that `GHC.IfaceToCore` displays Core Lint
errors for iface unfoldings as though they were a GHC panic. See, for
example, this excerpt from #17723:
```
ghc: panic! (the 'impossible' happened)
(GHC version 8.8.2 for x86_64-unknown-linux):
Iface Lint failure
In interface for Lib
...
```
This patch makes all of these code paths display Core Lint errors and
warnings consistently. I decided to adopt the conventions that
`lintPassResult` currently uses, as they appear to have been around the
longest (and look the best, in my subjective opinion). We now use the
`displayLintResult` function for all three scenarios mentioned above.
For example, here is what the Core Lint error for the program in #18770 looks
like after this patch:
```
[1 of 1] Compiling Bug ( Bug.hs, Bug.o )
*** Core Lint errors : in result of TcGblEnv axioms ***
Bug.hs:12:1: warning:
Non-*-like kind when *-like expected: RuntimeRep
when checking the body of forall: 'TupleRep '[r_axn]
In the coercion axiom N:T :: []. T ~_R Any
Substitution: [TCvSubst
In scope: InScope {r_axn}
Type env: [axn :-> r_axn]
Co env: []]
*** Offending Program ***
axiom N:T :: T = Any -- Defined at Bug.hs:12:1
*** End of Offense ***
<no location info>: error:
Compilation had errors
```
Fixes #18770.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/a9e5f52c571ae3dfd4826e10a256d1a265f7e058">a9e5f52c</a></strong>
<div>
<span>by Simon Peyton Jones</span>
<i>at 2020-11-02T23:47:31-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Expand type synonyms with :kind!
The User's Guide claims that `:kind!` should expand type synonyms,
but GHCi wasn't doing this in practice. Let's just update the implementation
to match the specification in the User's Guide.
Fixes #13795. Fixes #18828.
Co-authored-by: Ryan Scott <ryan.gl.scott@gmail.com>
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/1370eda7a53f5dfc88afe705b2ffecb1d5544ec7">1370eda7</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-02T23:48:06-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">hadrian: Don't capture RunTest output
There are a few reasons why capturing the output of the RunTest builder
is undesirable:
* there is a large amount of output which then gets unnecessarily
duplicated by Hadrian if the builder fails
* the output may contain codepoints which are unrepresentable in the
current codepage on Windows, causing Hadrian to crash
* capturing the output causes the testsuite driver to disable
its colorisation logic, making the output less legible.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/78f2767d4db5e69a142ac6a408a217b11c35949d">78f2767d</a></strong>
<div>
<span>by Matthew Pickering</span>
<i>at 2020-11-03T17:39:53-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Update inlining flags documentation
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/14ce454f7294381225b4211dc191a167a386e380">14ce454f</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-11-03T17:40:34-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Linker: reorganize linker related code
Move linker related code into GHC.Linker. Previously it was scattered
into GHC.Unit.State, GHC.Driver.Pipeline, GHC.Runtime.Linker, etc.
Add documentation in GHC.Linker
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/616bec0dee67ae4841c4e60e9406cc9c63358223">616bec0d</a></strong>
<div>
<span>by Alan Zimmerman</span>
<i>at 2020-11-03T17:41:10-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Restrict Linear arrow %1 to exactly literal 1 only
This disallows `a %001 -> b`, and makes sure the type literal is
printed from its SourceText so it is clear why.
Closes #18888
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/3486ebe6f960cc55d52c1e645ee15fdeb277d0ab">3486ebe6</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-11-03T17:41:48-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Hadrian: don't fail if ghc-tarballs dir doesn't exist
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/37f0434d65fa0891a961504c8882893fad7609c6">37f0434d</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-11-03T17:42:26-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Constant-folding: don't pass through GHC's Int/Word (fix #11704)
Constant-folding rules for integerToWord/integerToInt were performing
the following coercions at compilation time:
integerToWord: target's Integer -> ghc's Word -> target's Word
integerToInt : target's Integer -> ghc's Int -> target's Int
1) It was wrong for cross-compilers when GHC's word size is smaller than
the target one. This patch avoids passing through GHC's word-sized
types:
integerToWord: target's Integer -> ghc's Integer -> target's Word
integerToInt : target's Integer -> ghc's Integer -> target's Int
2) Additionally we didn't wrap the target word/int literal to make it
fit into the target's range! This broke the invariant of literals
only containing values in range.
The existing code is wrong only with a 64-bit cross-compiling GHC,
targeting a 32-bit platform, and performing constant folding on a
literal that doesn't fit in a 32-bit word. If GHC was built with
DEBUG, the assertion in GHC.Types.Literal.mkLitWord would fail.
Otherwise the bad transformation would go unnoticed.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bff74de713dac3e62c3bb6f1946e0649549f2215">bff74de7</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-11-03T17:43:03-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Bignum: make GMP's bignat_add not recursive
bignat_add was a loopbreaker with an INLINE pragma (spotted by
@mpickering). This patch makes it non recursive to avoid the issue.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bb100805337adc666867da300ee5b0b11c18fe00">bb100805</a></strong>
<div>
<span>by Andreas Klebinger</span>
<i>at 2020-11-04T16:47:24-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">NCG: Fix 64bit int comparisons on 32bit x86
We no compare these by doing 64bit subtraction and
checking the resulting flags.
We used to do this differently but the old approach was
broken when the high bits compared equal and the comparison
was one of >= or <=.
The new approach should be both correct and faster.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b790b7f91104197429cd80e2c192a6fcda9dd6b4">b790b7f9</a></strong>
<div>
<span>by Andreas Klebinger</span>
<i>at 2020-11-04T16:47:59-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Testsuite: Support for user supplied package dbs
We can now supply additional package dbs to the testsuite.
For make the package db can be supplied by
passing PACKAGE_DB=/path/to/db.
In the testsuite driver it's passed via the --test-package-db
argument.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/81560981fd9af7ea21b2592c405e9e22af838aab">81560981</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-11-04T16:48:42-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Don't use LEA with 8-bit registers (#18614)
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/17d5c51834d64f1762320b7abaa40c5686564f4d">17d5c518</a></strong>
<div>
<span>by Viktor Dukhovni</span>
<i>at 2020-11-05T00:50:23-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Naming, value types and tests for Addr# atomics
The atomic Exchange and CAS operations on integral types are updated to
take and return more natural `Word#` rather than `Int#` values. These
are bit-block not arithmetic operations, and the sign bit plays no
special role.
Standardises the names to `atomic<OpType><ValType>Addr#`, where `OpType` is one
of `Cas` or `Exchange` and `ValType` is presently either `Word` or `Addr`.
Eventually, variants for `Word32` and `Word64` can and should be added,
once #11953 and related issues (e.g. #13825) are resolved.
Adds tests for `Addr#` CAS that mirror existing tests for
`MutableByteArray#`.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2125b1d6bea0c620e3a089603dace6bb38020c81">2125b1d6</a></strong>
<div>
<span>by Ryan Scott</span>
<i>at 2020-11-05T00:51:01-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Add a regression test for #18920
Commit f594a68a5500696d94ae36425bbf4d4073aca3b2
(`Use level numbers for generalisation`) ended up fixing #18920. Let's add a
regression test to ensure that it stays fixed.
Fixes #18920.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/e07e383a3250cb27a9128ad8d5c68def5c3df336">e07e383a</a></strong>
<div>
<span>by Ryan Scott</span>
<i>at 2020-11-06T03:45:28-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Replace HsImplicitBndrs with HsOuterTyVarBndrs
This refactors the GHC AST to remove `HsImplicitBndrs` and replace it with
`HsOuterTyVarBndrs`, a type which records whether the outermost quantification
in a type is explicit (i.e., with an outermost, invisible `forall`) or
implicit. As a result of this refactoring, it is now evident in the AST where
the `forall`-or-nothing rule applies: it's all the places that use
`HsOuterTyVarBndrs`. See the revamped `Note [forall-or-nothing rule]` in
`GHC.Hs.Type` (previously in `GHC.Rename.HsType`).
Moreover, the places where `ScopedTypeVariables` brings lexically scoped type
variables into scope are a subset of the places that adhere to the
`forall`-or-nothing rule, so this also makes places that interact with
`ScopedTypeVariables` easier to find. See the revamped
`Note [Lexically scoped type variables]` in `GHC.Hs.Type` (previously in
`GHC.Tc.Gen.Sig`).
`HsOuterTyVarBndrs` are used in type signatures (see `HsOuterSigTyVarBndrs`)
and type family equations (see `HsOuterFamEqnTyVarBndrs`). The main difference
between the former and the latter is that the former cares about specificity
but the latter does not.
There are a number of knock-on consequences:
* There is now a dedicated `HsSigType` type, which is the combination of
`HsOuterSigTyVarBndrs` and `HsType`. `LHsSigType` is now an alias for an
`XRec` of `HsSigType`.
* Working out the details led us to a substantial refactoring of
the handling of explicit (user-written) and implicit type-variable
bindings in `GHC.Tc.Gen.HsType`.
Instead of a confusing family of higher order functions, we now
have a local data type, `SkolemInfo`, that controls how these
binders are kind-checked.
It remains very fiddly, not fully satisfying. But it's better
than it was.
Fixes #16762. Bumps the Haddock submodule.
Co-authored-by: Simon Peyton Jones <simonpj@microsoft.com>
Co-authored-by: Richard Eisenberg <rae@richarde.dev>
Co-authored-by: Zubin Duggal <zubin@cmi.ac.in>
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/c85f4928d4dbb2eb2cf906d08bfe7620d6f04ca5">c85f4928</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-11-06T03:46:08-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Refactor -dynamic-too handling
1) Don't modify DynFlags (too much) for -dynamic-too: now when we
generate dynamic outputs for "-dynamic-too", we only set "dynamicNow"
boolean field in DynFlags instead of modifying several other fields.
These fields now have accessors that take dynamicNow into account.
2) Use DynamicTooState ADT to represent -dynamic-too state. It's much
clearer than the undocumented "DynamicTooConditional" that was used
before.
As a result, we can finally remove the hscs_iface_dflags field in
HscRecomp. There was a comment on this field saying:
"FIXME (osa): I don't understand why this is necessary, but I spent
almost two days trying to figure this out and I couldn't .. perhaps
someone who understands this code better will remove this later."
I don't fully understand the details, but it was needed because of the
changes made to the DynFlags for -dynamic-too.
There is still something very dubious in GHC.Iface.Recomp: we have to
disable the "dynamicNow" flag at some point for some Backpack's "heinous
hack" to continue to work. It may be because interfaces for indefinite
units are always non-dynamic, or because we mix and match dynamic and
non-dynamic interfaces (#9176), or something else, who knows?
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2cb879092c0c946f5313216fc9ce4b93954c2f74">2cb87909</a></strong>
<div>
<span>by Moritz Angermann</span>
<i>at 2020-11-06T03:46:44-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">[AArch64] Aarch64 Always PIC
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b1d2c1f3246b3740589a59bdf7648c13de47c32b">b1d2c1f3</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-06T03:47:19-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts/Sanity: Avoid nasty race in weak pointer sanity-checking
See Note [Racing weak pointer evacuation] for all of the gory details.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/638f38c50e80a19275f3a06535a0dd8130a17a53">638f38c5</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-08T09:29:16-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Merge remote-tracking branch 'origin/wip/tsan/all'
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/22888798d224f96202480595fc49bc5c4b2f8328">22888798</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-11-08T12:08:40-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Fix haddock submodule
The previous merge mistakenly reverted it.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/befe4a8efef40af24cff7a16d078f74585a13cfc">befe4a8e</a></strong>
<div>
<span>by Ömer Sinan Ağacan</span>
<i>at 2020-11-09T19:19:57-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Fix and enable object unloading in GHCi
Fixes #16525 by tracking dependencies between object file symbols and
marking symbol liveness during garbage collection
See Note [Object unloading] in CheckUnload.c for details.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/79f42070a59332445b49a4d2f8abc8664240facb">79f42070</a></strong>
<div>
<span>by Ray Shih</span>
<i>at 2020-11-09T19:19:57-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Add loadNativeObj and unloadNativeObj
(This change is originally written by niteria)
This adds two functions:
* `loadNativeObj`
* `unloadNativeObj`
and implements them for Linux.
They are useful if you want to load a shared object with Haskell code
using the system linker and have GHC call dlclose() after the
code is no longer referenced from the heap.
Using the system linker allows you to load the shared object
above outside the low-mem region. It also loads the DWARF sections
in a way that `perf` understands.
`dl_iterate_phdr` is what makes this implementation Linux specific.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7470273c4e3b8882ec1b7c38cad3d091193a65c7">7470273c</a></strong>
<div>
<span>by GHC GitLab CI</span>
<i>at 2020-11-09T19:19:57-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">rts: Introduce highMemDynamic
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b9ca5fd987c82b0fb4124765875942360a9f87bd">b9ca5fd9</a></strong>
<div>
<span>by GHC GitLab CI</span>
<i>at 2020-11-09T19:19:57-05:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Introduce test for dynamic library unloading
This uses the highMemDynamic flag introduced earlier to verify that
dynamic objects are properly unloaded.
</pre>
</li>
</ul>
<h4>30 changed files:</h4>
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compiler/.hlint.yaml
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compiler/GHC.hs
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compiler/GHC/Builtin/primops.txt.pp
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compiler/GHC/Cmm/Graph.hs
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compiler/GHC/Cmm/LayoutStack.hs
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compiler/GHC/Core.hs
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compiler/GHC/Core/Coercion.hs
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compiler/GHC/Core/Lint.hs
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compiler/GHC/Core/Make.hs
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compiler/GHC/Core/Opt/ConstantFold.hs
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compiler/GHC/Core/Opt/Exitify.hs
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compiler/GHC/Core/Opt/Monad.hs
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compiler/GHC/Core/Opt/Pipeline.hs
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compiler/GHC/Core/Opt/Simplify.hs
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compiler/GHC/Core/Opt/SpecConstr.hs
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compiler/GHC/Core/Opt/Specialise.hs
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compiler/GHC/Core/Opt/StaticArgs.hs
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compiler/GHC/Core/TyCon/Env.hs
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