- Mar 10, 2021
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This adds two new methods to the Quasi class, putDoc and getDoc. They allow Haddock documentation to be added to declarations, module headers, function arguments and class/type family instances, as well as looked up. It works by building up a map of names to attach pieces of documentation to, which are then added in the extractDocs function in GHC.HsToCore.Docs. However because these template haskell names need to be resolved to GHC names at the time they are added, putDoc cannot directly add documentation to declarations that are currently being spliced. To remedy this, withDecDoc/withDecsDoc wraps the operation with addModFinalizer, and provides a more ergonomic interface for doing so. Similarly, the funD_doc, dataD_doc etc. combinators provide a more ergonomic interface for documenting functions and their arguments simultaneously. This also changes ArgDocMap to use an IntMap rather than an Map Int, for efficiency. Part of the work towards #5467
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Ben Gamari authored
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Previously, defining fields with DuplicateRecordFields in GHCi lead to strange shadowing behaviour, whereby fields would (accidentally) not shadow other fields. This simplifies things so that fields are shadowed in the same way whether or not DuplicateRecordFields is enabled.
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Related to #19381 #19359 #14702 After a spike in memory usage we have been conservative about returning allocated blocks to the OS in case we are still allocating a lot and would end up just reallocating them. The result of this was that up to 4 * live_bytes of blocks would be retained once they were allocated even if memory usage ended up a lot lower. For a heap of size ~1.5G, this would result in OS memory reporting 6G which is both misleading and worrying for users. In long-lived server applications this results in consistent high memory usage when the live data size is much more reasonable (for example ghcide) Therefore we have a new (2021) strategy which starts by retaining up to 4 * live_bytes of blocks before gradually returning uneeded memory back to the OS on subsequent major GCs which are NOT caused by a heap overflow. Each major GC which is NOT caused by heap overflow increases the consec_idle_gcs counter and the amount of memory which is retained is inversely proportional to this number. By default the excess memory retained is oldGenFactor (controlled by -F) / 2 ^ (consec_idle_gcs * returnDecayFactor) On a major GC caused by a heap overflow, the `consec_idle_gcs` variable is reset to 0 (as we could continue to allocate more, so retaining all the memory might make sense). Therefore setting bigger values for `-Fd` makes the rate at which memory is returned slower. Smaller values make it get returned faster. Setting `-Fd0` disables the memory return completely, which is the behaviour of older GHC versions. The default is `-Fd4` which results in the following scaling: > mapM print [(x, 1/ (2**(x / 4))) | x <- [1 :: Double ..20]] (1.0,0.8408964152537146) (2.0,0.7071067811865475) (3.0,0.5946035575013605) (4.0,0.5) (5.0,0.4204482076268573) (6.0,0.35355339059327373) (7.0,0.29730177875068026) (8.0,0.25) (9.0,0.21022410381342865) (10.0,0.17677669529663687) (11.0,0.14865088937534013) (12.0,0.125) (13.0,0.10511205190671433) (14.0,8.838834764831843e-2) (15.0,7.432544468767006e-2) (16.0,6.25e-2) (17.0,5.255602595335716e-2) (18.0,4.4194173824159216e-2) (19.0,3.716272234383503e-2) (20.0,3.125e-2) So after 13 consecutive GCs only 0.1 of the maximum memory used will be retained. Further to this decay factor, the amount of memory we attempt to retain is also influenced by the GC strategy for the oldest generation. If we are using a copying strategy then we will need at least 2 * live_bytes for copying to take place, so we always keep that much. If using compacting or nonmoving then we need a lower number, so we just retain at least `1.2 * live_bytes` for some protection. In future we might want to make this behaviour more aggressive, some relevant literature is > Ulan Degenbaev, Jochen Eisinger, Manfred Ernst, Ross McIlroy, and Hannes Payer. 2016. Idle time garbage collection scheduling. SIGPLAN Not. 51, 6 (June 2016), 570–583. DOI:https://doi.org/10.1145/2980983.2908106 which describes the "memory reducer" in the V8 javascript engine which on an idle collection immediately returns as much memory as possible.
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- Mar 09, 2021
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This fixes a regression that led to loss of location information in error messages about the use of tuple sections in patterns.
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It's surprisingly tricky to deal with 'main' (#19397). This patch does quite bit of refactoring do to it right. Well, more-right anyway! The moving parts are documented in GHC.Tc.Module Note [Dealing with main] Some other oddments: * Rename tcRnExports to rnExports; no typechecking here! * rnExports now uses checkNoErrs rather than failIfErrsM; the former fails only if rnExports itself finds errors * Small improvements to tcTyThingCategory, which ultimately weren't important to the patch, but I've retained as a minor improvement.
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- Mar 08, 2021
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The way in which allocatePinned took blocks out of the nursery was leading to horrible fragmentation in some workloads. The strategy now is that a separate free block list is reserved for each capability and blocks are taken from there. When it's empty the global SM lock is taken and a fresh block of size PINNED_EMPTY_SIZE is allocated. Fixes #19481
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- Mar 07, 2021
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Ben Gamari authored
This implements the BoxedRep proposal, refactoring the `RuntimeRep` hierarchy from: ```haskell data RuntimeRep = LiftedPtrRep | UnliftedPtrRep | ... ``` to ```haskell data RuntimeRep = BoxedRep Levity | ... data Levity = Lifted | Unlifted ``` Updates binary, haddock submodules. Closes #17526. Metric Increase: T12545
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- Mar 05, 2021
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This enables a registerised build for the riscv64 architecture.
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This addresses points (1a) and (1b) of #19165. - Move mkFailExpr to HsToCore/Utils, as it can be shared - Desugar incomplete patterns and holes to an empty case, as in Note [Incompleteness and linearity] - Enable linear linting of desugarer output - Mark MultConstructor as broken. It fails Lint, but I'd like to fix this separately. Metric Decrease: T6048
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Previously this test did nothing to prevent GHC from reading .ghci due to the `-e` arguments. Consequently it could fail due to multiple reloadings of DynFlags while evaluating .ghci.
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Commit 2a942285 dramatically simplified the implementation and improved the performance of COMPLETE sets while making them applicable in more scenarios at the same time. But it turned out that there was a change in semantics that (to me unexpectedly) broke users' expectations (see #14422): They relied on the "type signature" of a COMPLETE pragma to restrict the scrutinee types of a pattern match for which they are applicable. This patch brings back that filtering, so the semantics is the same as it was in GHC 9.0. See the updated Note [Implementation of COMPLETE pragmas]. There are a few testsuite output changes (`completesig13`, `T14422`) which assert this change. Co-authored-by:
Sebastian Graf <sebastian.graf@kit.edu>
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This was fixed as a result of #19181.
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Part of #17804.
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- Mar 03, 2021
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Matthew Pickering authored
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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. -
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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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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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. -
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.
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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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- Feb 28, 2021
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For years we have lived in a supposedly sweet spot that gave case binders the CPR property, unconditionally. Which is an optimistic hack that is now described in `Historical Note [Optimistic case binder CPR]`. In #19232 the concern was raised that this might do more harm than good and that might be better off simply by taking the CPR property of the scrutinee for the CPR type of the case binder. And indeed that's what we do now. Since `Note [CPR in a DataAlt case alternative]` is now only about field binders, I renamed and garbage collected it into `Note [Optimistic field binder CPR]`. NoFib approves: ``` NoFib Results -------------------------------------------------------------------------------- Program Allocs Instrs -------------------------------------------------------------------------------- anna +0.1% +0.1% nucleic2 -1.2% -0.6% sched 0.0% +0.9% transform -0.0% -0.1% -------------------------------------------------------------------------------- Min -1.2% -0.6% Max +0.1% +0.9% Geometric Mean -0.0% +0.0% ``` Fixes #19232.
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This test flip-flops by +-1% in arbitrary changes in CI. While playing around with `-dunique-increment`, I could reproduce variations of 3% in compiler allocations, so I set the acceptance window accordingly. Fixes #19414.
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The previous code using TyCoMapper could promote the same metavar twice. Use a set instead.
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- Feb 27, 2021
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The test probably could have used `usleep` from `unistd.h` instead, but this seemed like the simplest solution. Fixes #19431.
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When desugaring large overloaded literals we now avoid computing the `Rational` value. Instead prefering to store the significant and exponent as given where reasonable and possible. See Note [FractionalLit representation] for details.
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It should be left to tooling to perform the filtering to remove these specific closure types from the profile if desired. Fixes #16795
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