[Git][ghc/ghc][wip/refactor-demand] 112 commits: SMP.h: Add C11-style atomic operations
Sebastian Graf
gitlab at gitlab.haskell.org
Tue Nov 10 13:32:16 UTC 2020
Sebastian Graf pushed to branch wip/refactor-demand at Glasgow Haskell Compiler / GHC
Commits:
b9d4dd9c by Ben Gamari at 2020-10-24T20:44:17-04:00
SMP.h: Add C11-style atomic operations
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ccf2d4b0 by Ben Gamari at 2020-10-24T20:59:39-04:00
rts: Infrastructure for testing with ThreadSanitizer
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a61f66d6 by Ben Gamari at 2020-10-24T20:59:39-04:00
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.
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65136c13 by Ben Gamari at 2020-10-24T20:59:39-04:00
rts/Capability: Intialize interrupt field
Previously this was left uninitialized.
Also clarify some comments.
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b3ce6aca by Ben Gamari at 2020-10-24T20:59:39-04:00
rts/Task: Make comments proper Notes
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d3890ac7 by Ben Gamari at 2020-10-24T20:59:39-04:00
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.
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ef88712f by Ben Gamari at 2020-10-24T20:59:39-04:00
rts/OSThreads: Fix data race
Previously we would race on the cached processor count. Avoiding this is
straightforward; just use relaxed operations.
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33a719c3 by Ben Gamari at 2020-10-24T20:59:39-04:00
rts/ClosureMaros: Use relaxed atomics
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f08951fd by Ben Gamari at 2020-10-24T20:59:39-04:00
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.
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d584923a by Ben Gamari at 2020-10-24T20:59:39-04:00
testsuite: Fix thread leak in hs_try_putmvar00[13]
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bf1b0bc7 by Ben Gamari at 2020-10-24T20:59:39-04:00
rts: Introduce SET_HDR_RELEASE
Also ensure that we also store the info table pointer last to ensure
that the synchronization covers all stores.
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1a2e9f5e by Ben Gamari at 2020-10-24T21:00:19-04:00
gitlab-ci: Add nightly-x86_64-linux-deb9-tsan job
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58a5b0e5 by GHC GitLab CI at 2020-10-24T21:00:19-04:00
testsuite: Mark setnumcapabilities001 as broken with TSAN
Due to #18808.
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d9bc7dea by GHC GitLab CI at 2020-10-24T21:00:19-04:00
testsuite: Skip divbyzero and derefnull under TSAN
ThreadSanitizer changes the output of these tests.
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fcc42a10 by Ben Gamari at 2020-10-24T21:00:19-04:00
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.
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cae4bb3e by Ben Gamari at 2020-10-24T21:00:19-04:00
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.
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dae1b86a by Ben Gamari at 2020-10-24T21:00:19-04:00
testsuite: Mark T9872[abc] as high_memory_usage
These all have a maximum residency of over 2 GB.
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c5a0bb22 by Ben Gamari at 2020-10-24T21:00:19-04:00
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.
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4cb1232e by Ben Gamari at 2020-10-24T21:00:19-04:00
TSANUtils: Ensure that C11 atomics are supported
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7ed15f7f by Ben Gamari at 2020-10-24T21:00:19-04:00
testsuite: Mark T3807 as broken with TSAN
Due to #18883.
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f7e6f012 by Ben Gamari at 2020-10-24T21:00:19-04:00
testsuite: Mark T13702 as broken with TSAN due to #18884
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16b136b0 by Ben Gamari at 2020-10-24T21:00:36-04:00
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.
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2781d68c by Ben Gamari at 2020-10-24T21:00:36-04:00
rts: Annotate benign race in waitForCapability
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f6b4b492 by Ben Gamari at 2020-10-24T21:00:36-04:00
rts: Clarify locking behavior of releaseCapability_
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65219810 by Ben Gamari at 2020-10-24T21:00:36-04:00
rts: Add assertions for task ownership of capabilities
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31fa87ec by Ben Gamari at 2020-10-24T21:00:36-04:00
rts: Use relaxed atomics on n_returning_tasks
This mitigates the warning of a benign race on n_returning_tasks in
shouldYieldCapability.
See #17261.
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6517a2ea by Ben Gamari at 2020-10-24T21:00:36-04:00
rts: Mitigate races in capability interruption logic
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2e9ba3f2 by Ben Gamari at 2020-10-24T21:00:36-04:00
rts/Capability: Use relaxed operations for last_free_capability
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e10dde37 by Ben Gamari at 2020-10-24T21:00:37-04:00
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.
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855325cd by Ben Gamari at 2020-10-24T21:00:37-04:00
rts/Schedule: Use relaxed operations for sched_state
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811f915d by Ben Gamari at 2020-10-24T21:00:37-04:00
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.
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8d2b3c3d by Ben Gamari at 2020-10-24T21:00:37-04:00
rts: Eliminate data races on pending_sync
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f8871018 by Ben Gamari at 2020-10-24T21:00:37-04:00
rts/Schedule: Eliminate data races on recent_activity
We cannot safely use relaxed atomics here.
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d079b943 by Ben Gamari at 2020-10-24T21:00:37-04:00
rts: Avoid data races in message handling
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06f80497 by Ben Gamari at 2020-10-24T21:00:37-04:00
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.
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d4a87779 by Ben Gamari at 2020-10-24T21:00:38-04:00
rts/ThreadPaused: Avoid data races
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56778ab3 by Ben Gamari at 2020-10-24T21:00:38-04:00
rts/Schedule: Eliminate data races in run queue management
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086521f7 by Ben Gamari at 2020-10-24T21:00:38-04:00
rts: Eliminate shutdown data race on task counters
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abad9778 by Ben Gamari at 2020-10-24T21:00:38-04:00
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.
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2f56be8a by Ben Gamari at 2020-10-24T21:00:39-04:00
rts/Messages: Annotate benign race
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7c0cdab1 by Ben Gamari at 2020-10-24T21:00:39-04:00
rts/RaiseAsync: Synchronize what_next read
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6cc2a8a5 by Ben Gamari at 2020-10-24T21:00:39-04:00
rts/Task: Move debugTrace to avoid data race
Specifically, we need to hold all_tasks_mutex to read taskCount.
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bbaec97d by Ben Gamari at 2020-10-24T21:00:39-04:00
Disable flawed assertion
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dd175a92 by Ben Gamari at 2020-10-24T21:00:39-04:00
Document schedulePushWork race
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3416244b by Ben Gamari at 2020-10-24T21:00:40-04:00
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.
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dffd9432 by Ben Gamari at 2020-10-24T21:00:40-04:00
rts: Make write of to_cap->inbox atomic
This is necessary since emptyInbox may read from to_cap->inbox without
taking cap->lock.
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1f4cbc29 by Ben Gamari at 2020-10-24T21:00:57-04:00
rts/BlockAlloc: Use relaxed operations
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d0d07cff by Ben Gamari at 2020-10-24T21:00:57-04:00
rts: Rework handling of mutlist scavenging statistics
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9e5c7f6d by Ben Gamari at 2020-10-24T21:00:57-04:00
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.
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316add67 by Ben Gamari at 2020-10-24T21:00:57-04:00
rts/Storage: Use atomics
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5c23bc4c by Ben Gamari at 2020-10-24T21:00:58-04:00
rts/Updates: Use proper atomic operations
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3d0f033c by Ben Gamari at 2020-10-24T21:00:58-04:00
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.
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edb4b92b by Ben Gamari at 2020-10-24T21:01:18-04:00
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.
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d39bbd3d by Ben Gamari at 2020-10-24T21:01:33-04:00
rts: Use relaxed atomics for whitehole spin stats
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8f802f38 by Ben Gamari at 2020-10-24T21:01:33-04:00
rts: Avoid lock order inversion during fork
Fixes #17275.
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cef667b0 by GHC GitLab CI at 2020-10-24T21:01:34-04:00
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.
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8cf50eb1 by Ben Gamari at 2020-10-24T21:01:54-04:00
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.
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88a7ce38 by Ben Gamari at 2020-10-24T21:01:54-04:00
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.
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f97c59ce by Ben Gamari at 2020-10-24T21:02:11-04:00
Mitigate data races in event manager startup/shutdown
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c7c3f8aa by Ben Gamari at 2020-10-24T21:02:22-04:00
rts: Accept benign races in Proftimer
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5a98dfca by Ben Gamari at 2020-10-24T21:02:22-04:00
rts: Pause timer while changing capability count
This avoids #17289.
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01d95525 by Ben Gamari at 2020-10-24T21:02:22-04:00
Fix #17289
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9a528985 by Ben Gamari at 2020-10-24T21:02:23-04:00
suppress #17289 (ticker) race
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1726ec41 by Ben Gamari at 2020-10-24T21:02:23-04:00
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.
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bfbe4366 by Ben Gamari at 2020-10-24T21:02:23-04:00
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.
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297acc71 by Ben Gamari at 2020-10-24T21:02:44-04:00
rts/Stats: Hide a few unused unnecessarily global functions
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aad1f803 by Ben Gamari at 2020-10-30T00:41:14-04:00
rts/GC: Use atomics
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d0bc0517 by Ben Gamari at 2020-10-30T00:41:14-04:00
rts: Use RELEASE ordering in unlockClosure
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d44f5232 by Ben Gamari at 2020-10-30T00:41:14-04:00
rts/Storage: Accept races on heap size counters
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4e4a7386 by Ben Gamari at 2020-10-30T00:41:14-04:00
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.
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a80cc857 by GHC GitLab CI at 2020-10-30T00:41:14-04:00
rts: Fix race in GC CPU time accounting
Ensure that the GC leader synchronizes with workers before calling
stat_endGC.
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105d43db by Ben Gamari at 2020-10-30T14:02:19-04:00
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`).
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f7b45cde by Ben Gamari at 2020-10-30T14:02:19-04:00
rts: Use relaxed ordering on spinlock counters
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b1dda153 by Ben Gamari at 2020-11-01T12:58:36-05:00
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.
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5c2e6bce by Ben Gamari at 2020-11-01T12:58:36-05:00
rts: Tear down stats_mutex after exitHeapProfiling
Since the latter wants to call getRTSStats.
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ef25aaa1 by Ben Gamari at 2020-11-01T13:02:11-05:00
rts: Annotate hopefully "benign" races in freeGroup
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3a181553 by Ben Gamari at 2020-11-01T13:02:18-05:00
Strengthen ordering in releaseGCThreads
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af474f62 by Ben Gamari at 2020-11-01T13:05:38-05:00
Suppress data race due to close
This suppresses the other side of a race during shutdown.
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b4686bff by Ben Gamari at 2020-11-01T13:09:59-05:00
Merge branch 'wip/tsan/ci' into wip/tsan/all
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b8e66e0e by Ben Gamari at 2020-11-01T13:10:01-05:00
Merge branch 'wip/tsan/storage' into wip/tsan/all
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375512cf by Ben Gamari at 2020-11-01T13:10:02-05:00
Merge branch 'wip/tsan/wsdeque' into wip/tsan/all
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65ebf07e by Ben Gamari at 2020-11-01T13:10:03-05:00
Merge branch 'wip/tsan/misc' into wip/tsan/all
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55c375d0 by Ben Gamari at 2020-11-01T13:10:04-05:00
Merge branch 'wip/tsan/stm' into wip/tsan/all
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a9f75fe2 by Ben Gamari at 2020-11-01T13:10:06-05:00
Merge branch 'wip/tsan/event-mgr' into wip/tsan/all
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8325d658 by Ben Gamari at 2020-11-01T13:10:24-05:00
Merge branch 'wip/tsan/timer' into wip/tsan/all
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07e82ba5 by Ben Gamari at 2020-11-01T13:10:35-05:00
Merge branch 'wip/tsan/stats' into wip/tsan/all
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4ce2f7d6 by GHC GitLab CI at 2020-11-02T23:45:06-05:00
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.
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0b772221 by Ben Gamari at 2020-11-02T23:45:42-05:00
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.
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81006a06 by David Eichmann at 2020-11-02T23:46:19-05:00
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 at gmail.com>
Co-authored-by: Matthew Pickering <matthewtpickering at gmail.com>
Co-authored-by: Ben Gamari <bgamari.foss at gmail.com>
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bfb1e272 by Ryan Scott at 2020-11-02T23:46:55-05:00
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.
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a9e5f52c by Simon Peyton Jones at 2020-11-02T23:47:31-05:00
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 at gmail.com>
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1370eda7 by Ben Gamari at 2020-11-02T23:48:06-05:00
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.
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78f2767d by Matthew Pickering at 2020-11-03T17:39:53-05:00
Update inlining flags documentation
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14ce454f by Sylvain Henry at 2020-11-03T17:40:34-05:00
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
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616bec0d by Alan Zimmerman at 2020-11-03T17:41:10-05:00
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
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3486ebe6 by Sylvain Henry at 2020-11-03T17:41:48-05:00
Hadrian: don't fail if ghc-tarballs dir doesn't exist
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37f0434d by Sylvain Henry at 2020-11-03T17:42:26-05:00
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.
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bff74de7 by Sylvain Henry at 2020-11-03T17:43:03-05:00
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.
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bb100805 by Andreas Klebinger at 2020-11-04T16:47:24-05:00
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.
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b790b7f9 by Andreas Klebinger at 2020-11-04T16:47:59-05:00
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.
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81560981 by Sylvain Henry at 2020-11-04T16:48:42-05:00
Don't use LEA with 8-bit registers (#18614)
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17d5c518 by Viktor Dukhovni at 2020-11-05T00:50:23-05:00
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#`.
- - - - -
2125b1d6 by Ryan Scott at 2020-11-05T00:51:01-05:00
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.
- - - - -
e07e383a by Ryan Scott at 2020-11-06T03:45:28-05:00
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 at microsoft.com>
Co-authored-by: Richard Eisenberg <rae at richarde.dev>
Co-authored-by: Zubin Duggal <zubin at cmi.ac.in>
- - - - -
c85f4928 by Sylvain Henry at 2020-11-06T03:46:08-05:00
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?
- - - - -
2cb87909 by Moritz Angermann at 2020-11-06T03:46:44-05:00
[AArch64] Aarch64 Always PIC
- - - - -
b1d2c1f3 by Ben Gamari at 2020-11-06T03:47:19-05:00
rts/Sanity: Avoid nasty race in weak pointer sanity-checking
See Note [Racing weak pointer evacuation] for all of the gory details.
- - - - -
638f38c5 by Ben Gamari at 2020-11-08T09:29:16-05:00
Merge remote-tracking branch 'origin/wip/tsan/all'
- - - - -
22888798 by Ben Gamari at 2020-11-08T12:08:40-05:00
Fix haddock submodule
The previous merge mistakenly reverted it.
- - - - -
78c22006 by Sebastian Graf at 2020-11-10T14:32:07+01:00
Fix strictness signatures of `prefetchValue*#` primops
Their strictness signatures said the primops are strict in their first
argument, which is wrong: Handing it a thunk will prefetch the pointer
to the thunk, but not evaluate it. Hence not strict.
The regression test `T8256` actually tests for laziness in the first
argument, so GHC apparently never exploited the strictness signature.
See also https://gitlab.haskell.org/ghc/ghc/-/issues/8256#note_310867,
where this came up.
- - - - -
bebd73a7 by Sebastian Graf at 2020-11-10T14:32:07+01:00
Demand: Interleave usage and strictness demands (#18903)
As outlined in #18903, interleaving usage and strictness demands not
only means a more compact demand representation, but also allows us to
express demands that we weren't easily able to express before.
Call demands are *relative* in the sense that a call demand `Cn(cd)`
on `g` says "`g` is called `n` times. *Whenever `g` is called*, the
result is used according to `cd`". Example from #18903:
```hs
h :: Int -> Int
h m =
let g :: Int -> (Int,Int)
g 1 = (m, 0)
g n = (2 * n, 2 `div` n)
{-# NOINLINE g #-}
in case m of
1 -> 0
2 -> snd (g m)
_ -> uncurry (+) (g m)
```
Without the interleaved representation, we would just get `L` for the
strictness demand on `g`. Now we are able to express that whenever
`g` is called, its second component is used strictly in denoting `g`
by `1C1((1(U),S(U)))`. This would allow Nested CPR to unbox the
division, for example.
Now other advances in expressiveness like #18885 are possible.
Fixes #18903.
- - - - -
edea2fb9 by Sebastian Graf at 2020-11-10T14:32:07+01:00
Update user's guide entry on demand analysis and worker/wrapper
The demand signature notation has been undocumented for a long time.
The only source to understand it, apart from reading the `Outputable`
instance, has been an outdated wiki page.
Since the previous commits have reworked the demand lattice, I took
it as an opportunity to also write some documentation about notation.
- - - - -
30 changed files:
- .gitlab-ci.yml
- compiler/GHC.hs
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Cond.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Make.hs
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/Pipeline.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/CoreToStg.hs
- compiler/GHC/CoreToStg/Prep.hs
- compiler/GHC/Data/EnumSet.hs
- compiler/GHC/Driver/Backpack.hs
- compiler/GHC/Driver/Env.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Make.hs
- compiler/GHC/Driver/MakeFile.hs
- compiler/GHC/Driver/Pipeline.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Hs/Decls.hs
- compiler/GHC/Hs/Extension.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c70b5613a4ac59e4046feed23e7d99f388cdd958...edea2fb99faaa4706bcd781b508cc4e80b1715ba
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c70b5613a4ac59e4046feed23e7d99f388cdd958...edea2fb99faaa4706bcd781b508cc4e80b1715ba
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