[Git][ghc/ghc][wip/ci-fixes] 20 commits: Optimisations in Data.Foldable (T17867)

Ben Gamari gitlab at gitlab.haskell.org
Thu Dec 3 18:01:55 UTC 2020



Ben Gamari pushed to branch wip/ci-fixes at Glasgow Haskell Compiler / GHC


Commits:
49ebe369 by chessai at 2020-11-30T19:47:40-05:00
Optimisations in Data.Foldable (T17867)

This PR concerns the following functions from `Data.Foldable`:
* minimum
* maximum
* sum
* product
* minimumBy
* maximumBy

- Default implementations of these functions now use `foldl'` or `foldMap'`.
- All have been marked with INLINEABLE to make room for further optimisations.

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4d79ef65 by chessai at 2020-11-30T19:47:40-05:00
Apply suggestion to libraries/base/Data/Foldable.hs
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6af074ce by chessai at 2020-11-30T19:47:40-05:00
Apply suggestion to libraries/base/Data/Foldable.hs
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ab334262 by Viktor Dukhovni at 2020-11-30T19:48:17-05:00
dirty MVAR after mutating TSO queue head

While the original head and tail of the TSO queue may be in the same
generation as the MVAR, interior elements of the queue could be younger
after a GC run and may then be exposed by putMVar operation that updates
the queue head.

Resolves #18919

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5eb163f3 by Ben Gamari at 2020-11-30T19:48:53-05:00
rts/linker: Don't allow shared libraries to be loaded multiple times

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490aa14d by Ben Gamari at 2020-11-30T19:48:53-05:00
rts/linker: Initialise CCSs from native shared objects

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6ac3db5f by Ben Gamari at 2020-11-30T19:48:53-05:00
rts/linker: Move shared library loading logic into Elf.c

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b6698d73 by GHC GitLab CI at 2020-11-30T19:48:53-05:00
rts/linker: Don't declare dynamic objects with image_mapped

This previously resulted in warnings due to spurious unmap failures.

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b94a65af by jneira at 2020-11-30T19:49:31-05:00
Include tried paths in findToolDir error

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72a87fbc by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Move core flattening algorithm to Core.Unify

This sets the stage for a later change, where this
algorithm will be needed from GHC.Core.InstEnv.

This commit also splits GHC.Core.Map into
GHC.Core.Map.Type and GHC.Core.Map.Expr,
in order to avoid module import cycles
with GHC.Core.

- - - - -
0dd45d0a by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Bump the # of commits searched for perf baseline

The previous value of 75 meant that a feature branch with
more than 75 commits would get spurious CI passes.

This affects #18692, but does not fix that ticket, because
if a baseline cannot be found, we should fail, not succeed.

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8bb52d91 by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Remove flattening variables

This patch redesigns the flattener to simplify type family applications
directly instead of using flattening meta-variables and skolems. The key new
innovation is the CanEqLHS type and the new CEqCan constraint (Ct). A CanEqLHS
is either a type variable or exactly-saturated type family application; either
can now be rewritten using a CEqCan constraint in the inert set.

Because the flattener no longer reduces all type family applications to
variables, there was some performance degradation if a lengthy type family
application is now flattened over and over (not making progress). To
compensate, this patch contains some extra optimizations in the flattener,
leading to a number of performance improvements.

Close #18875.
Close #18910.

There are many extra parts of the compiler that had to be affected in writing
this patch:

* The family-application cache (formerly the flat-cache) sometimes stores
  coercions built from Given inerts. When these inerts get kicked out, we must
  kick out from the cache as well. (This was, I believe, true previously, but
  somehow never caused trouble.) Kicking out from the cache requires adding a
  filterTM function to TrieMap.

* This patch obviates the need to distinguish "blocking" coercion holes from
  non-blocking ones (which, previously, arose from CFunEqCans). There is thus
  some simplification around coercion holes.

* Extra commentary throughout parts of the code I read through, to preserve
  the knowledge I gained while working.

* A change in the pure unifier around unifying skolems with other types.
  Unifying a skolem now leads to SurelyApart, not MaybeApart, as documented
  in Note [Binding when looking up instances] in GHC.Core.InstEnv.

* Some more use of MCoercion where appropriate.

* Previously, class-instance lookup automatically noticed that e.g. C Int was
  a "unifier" to a target [W] C (F Bool), because the F Bool was flattened to
  a variable. Now, a little more care must be taken around checking for
  unifying instances.

* Previously, tcSplitTyConApp_maybe would split (Eq a => a). This is silly,
  because (=>) is not a tycon in Haskell. Fixed now, but there are some
  knock-on changes in e.g. TrieMap code and in the canonicaliser.

* New function anyFreeVarsOf{Type,Co} to check whether a free variable
  satisfies a certain predicate.

* Type synonyms now remember whether or not they are "forgetful"; a forgetful
  synonym drops at least one argument. This is useful when flattening; see
  flattenView.

* The pattern-match completeness checker invokes the solver. This invocation
  might need to look through newtypes when checking representational equality.
  Thus, the desugarer needs to keep track of the in-scope variables to know
  what newtype constructors are in scope. I bet this bug was around before but
  never noticed.

* Extra-constraints wildcards are no longer simplified before printing.
  See Note [Do not simplify ConstraintHoles] in GHC.Tc.Solver.

* Whether or not there are Given equalities has become slightly subtler.
  See the new HasGivenEqs datatype.

* Note [Type variable cycles in Givens] in GHC.Tc.Solver.Canonical
  explains a significant new wrinkle in the new approach.

* See Note [What might match later?] in GHC.Tc.Solver.Interact, which
  explains the fix to #18910.

* The inert_count field of InertCans wasn't actually used, so I removed
  it.

Though I (Richard) did the implementation, Simon PJ was very involved
in design and review.

This updates the Haddock submodule to avoid #18932 by adding
a type signature.

-------------------------
Metric Decrease:
    T12227
    T5030
    T9872a
    T9872b
    T9872c
Metric Increase:
    T9872d
-------------------------

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d66660ba by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Rename the flattener to become the rewriter.

Now that flattening doesn't produce flattening variables,
it's not really flattening anything: it's rewriting. This
change also means that the rewriter can no longer be confused
the core flattener (in GHC.Core.Unify), which is sometimes used
during type-checking.

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add0aeae by Ben Gamari at 2020-12-01T19:58:17-05:00
rts: Introduce mmapAnonForLinker

Previously most of the uses of mmapForLinker were mapping anonymous
memory, resulting in a great deal of unnecessary repetition. Factor this
out into a new helper.

Also fixes a few places where error checking was missing or suboptimal.

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97d71646 by Ben Gamari at 2020-12-01T19:58:17-05:00
rts/linker: Introduce munmapForLinker

Consolidates munmap calls to ensure consistent error handling.

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d8872af0 by Ben Gamari at 2020-12-01T19:58:18-05:00
rts/Linker: Introduce Windows implementations for mmapForLinker, et al.

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c35d0e03 by Ben Gamari at 2020-12-01T19:58:18-05:00
rts/m32: Introduce NEEDS_M32 macro

Instead of relying on RTS_LINKER_USE_MMAP

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41c64eb5 by Ben Gamari at 2020-12-01T19:58:18-05:00
rts/linker: Use m32 to allocate symbol extras in PEi386

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e0b08c5f by Ben Gamari at 2020-12-03T13:01:47-05:00
gitlab-ci: Fix copy-paste error

Also be more consistent in quoting.

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f85141e3 by Ben Gamari at 2020-12-03T13:01:47-05:00
gitlab-ci: Run linters through ci.sh

Ensuring that the right toolchain is used.

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30 changed files:

- .gitlab-ci.yml
- .gitlab/ci.sh
- compiler/GHC/Cmm/CommonBlockElim.hs
- compiler/GHC/Cmm/Dataflow/Label.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion.hs-boot
- compiler/GHC/Core/Coercion/Axiom.hs
- compiler/GHC/Core/Coercion/Opt.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/InstEnv.hs
- + compiler/GHC/Core/Map/Expr.hs
- compiler/GHC/Core/Map.hs → compiler/GHC/Core/Map/Type.hs
- compiler/GHC/Core/Opt/CSE.hs
- compiler/GHC/Core/TyCo/FVs.hs
- compiler/GHC/Core/TyCo/Rep.hs
- compiler/GHC/Core/TyCon.hs
- compiler/GHC/Core/TyCon/Env.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Unify.hs
- compiler/GHC/Data/Bag.hs
- compiler/GHC/Data/Maybe.hs
- compiler/GHC/Data/TrieMap.hs
- compiler/GHC/Driver/Flags.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/HsToCore/Monad.hs
- compiler/GHC/HsToCore/Pmc/Solver.hs
- compiler/GHC/HsToCore/Pmc/Solver/Types.hs
- compiler/GHC/HsToCore/Types.hs
- compiler/GHC/Iface/Ext/Utils.hs
- compiler/GHC/Stg/CSE.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/bf66d123e7eeb264105fc9483f061c404ab50285...f85141e32b34b6e747be17bf0589329b54c6ea96

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