- Mar 03, 2021
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Matthew Pickering authored -
Matthew Pickering authored
The `whereFrom` function provides a Haskell interface for using the information created by `-finfo-table-map`. Given a Haskell value, the info table address will be passed to the `lookupIPE` function in order to attempt to find the source location information for that particular closure. At the moment it's not possible to distinguish the absense of the map and a failed lookup.
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Matthew Pickering authored
The `-fdistinct-constructor-tables` flag will generate a fresh info table for the usage of any data constructor. This is useful for debugging as now by inspecting the info table, you can determine which usage of a constructor caused that allocation rather than the old situation where the info table always mapped to the definition site of the data constructor which is useless. In conjunction with `-hi` and `-finfo-table-map` this gives a more fine grained understanding of where constructor allocations arise from in a program.
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Matthew Pickering authored
This new flag embeds a lookup table from the address of an info table to information about that info table. The main interface for consulting the map is the `lookupIPE` C function > InfoProvEnt * lookupIPE(StgInfoTable *info) The `InfoProvEnt` has the following structure: > typedef struct InfoProv_{ > char * table_name; > char * closure_desc; > char * ty_desc; > char * label; > char * module; > char * srcloc; > } InfoProv; > > typedef struct InfoProvEnt_ { > StgInfoTable * info; > InfoProv prov; > struct InfoProvEnt_ *link; > } InfoProvEnt; The source positions are approximated in a similar way to the source positions for DWARF debugging information. They are only approximate but in our experience provide a good enough hint about where the problem might be. It is therefore recommended to use this flag in conjunction with `-g<n>` for more accurate locations. The lookup table is also emitted into the eventlog when it is available as it is intended to be used with the `-hi` profiling mode. Using this flag will significantly increase the size of the resulting object file but only by a factor of 2-3x in our experience. -
Matthew Pickering authored
This profiling mode creates bands by the address of the info table for each closure. This provides a much more fine-grained profiling output than any of the other profiling modes. The `-hi` profiling mode does not require a profiling build.
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Matthew Pickering authored
This reverts commit 1c7c6f1a.
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As reported in #19432, the rules governing how `DefaultSignatures` are typechecked became stricter in GHC 9.0 due to simplified subsumption. However, this was far from obvious to me after reading the User's Guide section on `DefaultSignatures`. In this patch, I spruce up the documentation in that section so that it mentions these nuances. Resolves #19432.
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This applies the fix for #19033 to all the other flavours as well.
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The update of the Outputable instance resulted in a slew of documentation changes within Notes that used the old syntax. The most important doc changes are to `Note [Demand notation]` and the user's guide. Fixes #19016.
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Previously a255b4e3 failed to update the non-profiling codepath.
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Previously the profiled flavour transformer failed to add the profiled ways to the library and RTS ways lists, resulting in link failures.
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Thanks @mpickering for finding them!
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Avoid returning a lazy panic value when leak indicators are disabled.
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($) is INLINE so there is no reason ($!) shouldn't.
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This patch exposes three new functions in `GHC.Profiling` which allow heap profiling to be enabled and disabled dynamically. 1. startHeapProfTimer - Starts heap profiling with the given RTS options 2. stopHeapProfTimer - Stops heap profiling 3. requestHeapCensus - Perform a heap census on the next context switch, regardless of whether the timer is enabled or not. -
The first change makes the array ones use the proper fixed-size types, which also means that just like before, they can be used without explicit conversions with the boxed sized types. (Before, it was Int# / Word# on both sides, now it is fixed sized on both sides). For the second change, don't use "extend" or "narrow" in some of the user-facing primops names for conversions. - Names like `narrowInt32#` are misleading when `Int` is 32-bits. - Names like `extendInt64#` are flat-out wrong when `Int is 32-bits. - `narrow{Int,Word}<N>#` however map a type to itself, and so don't suffer from this problem. They are left as-is. These changes are batched together because Alex happend to use the array ops. We can only use released versions of Alex at this time, sadly, and I don't want to have to have a release thatwon't work for the final GHC 9.2. So by combining these we get all the changes for Alex done at once. Bump hackage state in a few places, and also make that workflow slightly easier for the future. Bump minimum Alex version Bump Cabal, array, bytestring, containers, text, and binary submodules -
Add Data.Type.Ord Add and update tests Metric Increase: MultiLayerModules -
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- Mar 02, 2021
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Fixes #17895.
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Fixes #17953
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Previously the eventlog infrastructure had a couple of races that could pop up when using the startEventLog/endEventLog interfaces. In particular, stopping and then later restarting logging could result in data preceding the eventlog header, breaking the integrity of the stream. To fix this we rework the invariants regarding the eventlog and generally tighten up the concurrency control surrounding starting and stopping of logging. We also fix an unrelated bug, wherein log events from disabled capabilities could end up never flushed.
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- Mar 01, 2021
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Consider (`T18610`): ```hs f :: Bool -> Int f x = case (x, x) of (True, True) -> 1 (False, False) -> 2 (True, False) -> 3 -- Warning: Redundant ``` The third clause will be flagged as redundant. Nevertheless, the programmer might intend to keep the clause in order to avoid bitrot. After this patch, the programmer can write ```hs g :: Bool -> Int g x = case (x, x) of (True, True) -> 1 (False, False) -> 2 (True, False) | GHC.Exts.considerAccessible -> 3 -- No warning ``` And won't be bothered any longer. See also `Note [considerAccessible]` and the updated entries in the user's guide. Fixes #18610 and #19228. -
While fixing #18610, I noticed that ```hs f :: Bool -> Int f x = case (x, x) of (True, True) -> 1 (False, False) -> 2 ``` was *not* detected as exhaustive. I tracked it down to `equateUSDFM`, where upon merging equality classes of `x` and `y`, we failed to atually indirect the *representative* `x'` of the equality class of `x` to the representative `y'` of `y`. The fixed code is much more naturally and would I should have written in the first place. I can confirm that the above example now is detected as exhaustive. The commit that fixes #18610 comes directly after and it has `f` above as a regression test, so I saw no need to open a ticket or commit a separate regression test.
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If the context is missing it is captured as Nothing, rather than putting a noLoc in the ParsedSource. Updates haddock submodule
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Ticket #19360 showed up a terrible bug in the occurrence analyser, in a situation like this Rec { f = g ; g = ..f... {-# RULE g .. = ...f... #-} } Then f was postInlineUnconditionally, but not in the RULE (which is simplified first), so we had a RULE mentioning a variable that was not in scope. This led me to review (again) the subtle loop-breaker stuff in the occurrence analyser. The actual changes are few, and are largely simplifications. I did a /lot/ of comment re-organising though. There was an unexpected amount of fallout. * Validation failed when compiling the stage2 compiler with profiling on. That turned to tickle a second latent bug in the same OccAnal code (at least I think it was always there), which led me to simplify still further; see Note [inl_fvs] in GHC.Core.Opt.OccurAnal. * But that in turn let me to some strange behaviour in CSE when ticks are in the picture, which I duly fixed. See Note [Dealing with ticks] in GHC.Core.Opt.CSE. * Then I got an ASSERT failure in CoreToStg, which again seems to be a latent bug. See Note [Ticks in applications] in GHC.CoreToStg * I also made one unforced change: I now simplify the RHS of a RULE in the same way as the RHS of a stable unfolding. This can allow a trivial binding to disappear sooner than otherwise, and I don't think it has any downsides. The change is in GHC.Core.Opt.Simplify.simplRules. -
This is a first step towards #18738.
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Ticket #19364 helpfully points out that we do not currently take advantage of pushing the result type of an application into the arguments. This makes error messages notably less good. The fix is rather easy: move the result-type unification step earlier. It's even a bit more efficient; in the the checking case we now do one less zonk. See Note [Unify with expected type before typechecking arguments] in GHC.Tc.Gen.App This change generally improves error messages, but it made one worse: typecheck/should_fail/T16204c. That led me to the realisation that a good error can be replaced by a less-good one, which provoked me to change GHC.Tc.Solver.Interact.inertsCanDischarge. It's explained in the new Note [Combining equalities] One other refactoring: I discovered that KindEqOrigin didn't need a Maybe in its type -- a nice simplification.
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As #19293 realises, this one keeps on flip flopping by 2.5% depending on how many modules there are within the GHC package. We should revert this once we figured out how to fix what's going on.
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Ben Gamari authored
Metric Decrease: T10421 -
Ben Gamari authored
Previously flushEventLog failed to flush anything but the global event buffer in the non-threaded RTS. Fixes #19436.
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Ben Gamari authored
The previous approach performed the flush in yieldCapability. However, as pointed out in #19435, this is wrong as it idle capabilities will not go through this codepath. The fix is simple: undo the optimisation, flushing in `flushEventLog` by calling `flushAllCapsEventsBufs` after acquiring all capabilities. Fixes #19435.
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- Feb 28, 2021
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Reduce code bloat by replacing a call to `(==)` (which is defined in terms of `compare`) and to `compare` by a single call to `compare`, utilising the `Semigroup Ordering` instance. The compiler was eliminate the code bloat before, so this is a rather cosmetical improvement. Fixes #19443.
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Previously, non-determinism arising from a use of `uniqCompareFS` in `cmpLit` potentially crept into `CoreMap`, which we expect to behave deterministically. So we simply use `lexicalCompareFS` now. Fixes #19438.
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While fixing #17336 we noticed that code like this: = if | tc == intTyConName -> ... | tc == int8TyConName -> ... | tc == int16TyConName -> ... | tc == int32TyConName -> ... | tc == int64TyConName -> ... | tc == wordTyConName -> ... | tc == word8TyConName -> ... | tc == word16TyConName -> ... | tc == word32TyConName -> ... | tc == word64TyConName -> ... | tc == naturalTyConName -> ... was not transformed into a single case expression on the Name's unique as I would have expected but as a linear search. Bindings for known names are not simple constructor applications because of their strict `n_occ :: !OccName` field that needs to allocate a `FastString`: this field needs to be forced before using the `n_unique` field. This patch partially reverses ccaf7b66 by making `n_occ` lazy and by ensuring that helper functions used to declare known names are fully inlined. The code above is then optimised as expected. Baseline Test Metric value New value Change --------------------------------------------------------------------------- ManyAlternatives(normal) ghc/alloc 822810880.0 822104032.0 -0.1% ManyConstructors(normal) ghc/alloc 4551734924.0 4480621808.0 -1.6% MultiLayerModules(normal) ghc/alloc 6029108292.0 6016024464.0 -0.2% Naperian(optasm) ghc/alloc 57396600.0 56826184.0 -1.0% PmSeriesG(normal) ghc/alloc 55666656.0 54521840.0 -2.1% PmSeriesS(normal) ghc/alloc 70204344.0 69047328.0 -1.6% PmSeriesT(normal) ghc/alloc 102273172.0 101070016.0 -1.2% PmSeriesV(normal) ghc/alloc 69157156.0 68002176.0 -1.7% T10421(normal) ghc/alloc 129875476.0 128881544.0 -0.8% T10421a(normal) ghc/alloc 92031552.0 90982800.0 -1.1% T10547(normal) ghc/alloc 34399800.0 33016760.0 -4.0% GOOD T10858(normal) ghc/alloc 208316964.0 207318616.0 -0.5% T11195(normal) ghc/alloc 304100548.0 302797040.0 -0.4% T11276(normal) ghc/alloc 140586764.0 139469832.0 -0.8% T11303b(normal) ghc/alloc 52118960.0 51120248.0 -1.9% T11374(normal) ghc/alloc 241325868.0 240692752.0 -0.3% T11822(normal) ghc/alloc 150612036.0 149582736.0 -0.7% T12150(optasm) ghc/alloc 92738452.0 91897224.0 -0.9% T12227(normal) ghc/alloc 494236296.0 493086728.0 -0.2% T12234(optasm) ghc/alloc 66786816.0 65966096.0 -1.2% T12425(optasm) ghc/alloc 112396704.0 111471016.0 -0.8% T12545(normal) ghc/alloc 1832733768.0 1828021072.0 -0.3% T12707(normal) ghc/alloc 1054991144.0 1053359696.0 -0.2% T13035(normal) ghc/alloc 116173180.0 115112072.0 -0.9% T13056(optasm) ghc/alloc 391749192.0 390687864.0 -0.3% T13253(normal) ghc/alloc 382785700.0 381550592.0 -0.3% T13253-spj(normal) ghc/alloc 168806064.0 167987192.0 -0.5% T13379(normal) ghc/alloc 403890296.0 402447920.0 -0.4% T13701(normal) ghc/alloc 2542828108.0 2534392736.0 -0.3% T13719(normal) ghc/alloc 4666717708.0 4659489416.0 -0.2% T14052(ghci) ghc/alloc 2181268580.0 2175320640.0 -0.3% T14683(normal) ghc/alloc 3094166824.0 3094524216.0 +0.0% T14697(normal) ghc/alloc 376323432.0 374024184.0 -0.6% T15164(normal) ghc/alloc 1896324828.0 1893236528.0 -0.2% T15630(normal) ghc/alloc 198932800.0 197783656.0 -0.6% T16190(normal) ghc/alloc 288186840.0 287250024.0 -0.3% T16577(normal) ghc/alloc 8324100940.0 8321580600.0 -0.0% T17096(normal) ghc/alloc 318264420.0 316961792.0 -0.4% T17516(normal) ghc/alloc 1332680768.0 1331635504.0 -0.1% T17836(normal) ghc/alloc 1296308168.0 1291098504.0 -0.4% T17836b(normal) ghc/alloc 62008340.0 60745256.0 -2.0% T17977(normal) ghc/alloc 52954564.0 51890248.0 -2.0% T17977b(normal) ghc/alloc 47824016.0 46683936.0 -2.4% T18140(normal) ghc/alloc 117408932.0 116353672.0 -0.9% T18223(normal) ghc/alloc 5603767896.0 5602037104.0 -0.0% T18282(normal) ghc/alloc 166456808.0 165396320.0 -0.6% T18304(normal) ghc/alloc 103694052.0 103513136.0 -0.2% T18478(normal) ghc/alloc 816819336.0 814459560.0 -0.3% T18698a(normal) ghc/alloc 438652404.0 437041784.0 -0.4% T18698b(normal) ghc/alloc 529448324.0 527666608.0 -0.3% T18923(normal) ghc/alloc 78360824.0 77315560.0 -1.3% T1969(normal) ghc/alloc 854223208.0 851303488.0 -0.3% T3064(normal) ghc/alloc 200655808.0 199368872.0 -0.6% T3294(normal) ghc/alloc 1791121792.0 1790033888.0 -0.1% T4801(normal) ghc/alloc 343749816.0 341760680.0 -0.6% T5030(normal) ghc/alloc 377520872.0 376492360.0 -0.3% T5321FD(normal) ghc/alloc 312680408.0 311618536.0 -0.3% T5321Fun(normal) ghc/alloc 355635656.0 354536264.0 -0.3% T5631(normal) ghc/alloc 629667068.0 629562192.0 -0.0% T5642(normal) ghc/alloc 540913864.0 539569952.0 -0.2% T5837(normal) ghc/alloc 43183652.0 42177928.0 -2.3% T6048(optasm) ghc/alloc 96395616.0 95397032.0 -1.0% T783(normal) ghc/alloc 427778908.0 426307760.0 -0.3% T9020(optasm) ghc/alloc 279523960.0 277010040.0 -0.9% T9233(normal) ghc/alloc 966717488.0 964594096.0 -0.2% T9630(normal) ghc/alloc 1585228636.0 1581428672.0 -0.2% T9675(optasm) ghc/alloc 594817892.0 591703040.0 -0.5% T9872a(normal) ghc/alloc 2216955420.0 2215648024.0 -0.1% T9872b(normal) ghc/alloc 2747814924.0 2746515472.0 -0.0% T9872c(normal) ghc/alloc 2271878772.0 2270554344.0 -0.1% T9872d(normal) ghc/alloc 623661168.0 621434064.0 -0.4% T9961(normal) ghc/alloc 409059124.0 406811120.0 -0.5% WWRec(normal) ghc/alloc 940563924.0 938008112.0 -0.3% hie002(normal) ghc/alloc 9801941116.0 9787675736.0 -0.1% parsing001(normal) ghc/alloc 494756632.0 493828512.0 -0.2% Metric Decrease: T10547 T13035 T12425 -
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The CODEOWNERS documentation has this to say on the current matching behaviour: > The path definition order is significant: the last pattern matching a > given path is used to find the code owners. Take this as an example: /rts/ bgamari [...] /rts/win32/ Phyx (I'm omitting the '@' so as to not notification spam everyone) This means a change in a file under win23 would only have Phyx but not bgamari as approver. I don't think that's the behaviour we want. Using "sections" we can get additive behaviour instead, from the docs: > Additionally, the usual guidance that only the last pattern matching the > file is applied is expanded such that the last pattern matching for each > section is applied. [RTS] /rts/ bgamari [...] [WinIO] /rts/win32/ Phyx So now since those entries are in different sections both would be added to the approvers list. The sections feature was introduced in Gitlab 13.2, see "Version history" on [1] we're currently running 18.8 on gitlab.haskell.org, see [2]. [1]: https://docs.gitlab.com/13.8/ee/user/project/code_owners.html#code-owners-sections [2]: https://gitlab.haskell.org/help
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