[Git][ghc/ghc][wip/T18141] 49 commits: nonmoving: Clear bitmap after initializing block size

Sat May 9 19:28:11 UTC 2020

Ben Gamari pushed to branch wip/T18141 at Glasgow Haskell Compiler / GHC

Commits:
2aa67611 by Ben Gamari at 2020-04-30T21:34:44-04:00
nonmoving: Clear bitmap after initializing block size

Previously nonmovingInitSegment would clear the bitmap before
initializing the segment's block size. This is broken since
nonmovingClearBitmap looks at the segment's block size to determine how
much bitmap to clear.

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54dad3cf by Ben Gamari at 2020-04-30T21:34:44-04:00
nonmoving: Explicitly memoize block count

A profile cast doubt on whether the compiler hoisted the bound out the
loop as I would have expected here. It turns out it did but nevertheless
it seems clearer to just do this manually.

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99ff8145 by Ben Gamari at 2020-04-30T21:34:44-04:00
nonmoving: Eagerly flush all capabilities' update remembered sets

(cherry picked from commit 2fa79119570b358a4db61446396889b8260d7957)

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05b0a9fd by Ömer Sinan Ağacan at 2020-04-30T21:35:24-04:00
Remove OneShotInfo field of LFReEntrant, document OneShotInfo

The field is only used in withNewTickyCounterFun and it's easier to
directly pass a parameter for one-shot info to withNewTickyCounterFun
instead of passing it via LFReEntrant. This also makes !2842 simpler.

Other changes:

- New Note (by SPJ) [OneShotInfo overview] added.
- Arity argument of thunkCode removed as it's always 0.

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a43620c6 by Ömer Sinan Ağacan at 2020-04-30T21:35:24-04:00
GHC.StgToCmm.Ticky: remove a few unused stuff

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780de9e1 by Sylvain Henry at 2020-05-01T10:37:39-04:00
Use platform in Iface Binary

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f8386c7b by Sylvain Henry at 2020-05-01T10:37:39-04:00
Refactor PprDebug handling

If `-dppr-debug` is set, then PprUser and PprDump styles are silently
replaced with PprDebug style. This was done in `mkUserStyle` and
`mkDumpStyle` smart constructors. As a consequence they needed a
DynFlags parameter.

Now we keep the original PprUser and PprDump styles until they are used
to create an `SDocContext`. I.e. the substitution is only performed in
`initSDocContext`.

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b3df9e78 by Sylvain Henry at 2020-05-01T10:37:39-04:00
Remove PprStyle param of logging actions

Use `withPprStyle` instead to apply a specific style to a SDoc.

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de9fc995 by Sylvain Henry at 2020-05-01T10:37:39-04:00
Fully remove PprDebug

PprDebug was a pain to deal with consistently as it is implied by
`-dppr-debug` but it isn't really a PprStyle. We remove it completely
and query the appropriate SDoc flag instead (`sdocPprDebug`) via
helpers (`getPprDebug` and its friends).

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8b51fcbd by Sebastian Graf at 2020-05-01T10:38:16-04:00
PmCheck: Only call checkSingle if we would report warnings

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fd7ea0fe by Sebastian Graf at 2020-05-01T10:38:16-04:00
PmCheck: Pick up `EvVar`s bound in `HsWrapper`s for long-distance info

`HsWrapper`s introduce evidence bindings through `WpEvLam` which the
pattern-match coverage checker should be made aware of.

Failing to do so caused #18049, where the resulting impreciseness of
imcompleteness warnings seemingly contradicted with
`-Winaccessible-code`.

The solution is simple: Collect all the evidence binders of an
`HsWrapper` and add it to the ambient `Deltas` before desugaring
the wrapped expression.

But that means we pick up many more evidence bindings, even when they
wrap around code without a single pattern match to check! That regressed
`T3064` by over 300%, so now we are adding long-distance info lazily
through judicious use of `unsafeInterleaveIO`.

Fixes #18049.

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7bfe9ac5 by Ben Gamari at 2020-05-03T04:41:33-04:00
rts: Enable tracing of nonmoving heap census with -ln

Previously this was not easily available to the user. Fix this.
Non-moving collection lifecycle events are now reported with -lg.

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c560dd07 by Ben Gamari at 2020-05-03T04:41:33-04:00
users guide: Move eventlog documentation users guide

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02543d5e by Ben Gamari at 2020-05-03T04:41:33-04:00
users guide: Add documentation for non-moving GC events

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b465dd45 by Alexis King at 2020-05-03T04:42:12-04:00
Flatten nested casts in the simple optimizer

Normally, we aren’t supposed to generated any nested casts, since mkCast
takes care to flatten them, but the simple optimizer didn’t use mkCast,
so they could show up after inlining. This isn’t really a problem, since
the simplifier will clean them up immediately anyway, but it can clutter
the -ddump-ds output, and it’s an extremely easy fix.

closes #18112

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8bdc03d6 by Simon Peyton Jones at 2020-05-04T01:56:59-04:00
Don't return a panic in tcNestedSplice

In GHC.Tc.Gen.Splice.tcNestedSplice we were returning a
typechecked expression of "panic". That is usually OK, because
the result is discarded.  But it happens that tcApp now looks at
the typechecked expression, trivially, to ask if it is tagToEnum.
So being bottom is bad.

Moreover a debug-trace might print it out.

So better to return a civilised expression, even though it is
usually discarded.

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0bf640b1 by Baldur Blöndal at 2020-05-04T01:57:36-04:00
Don't require parentheses around via type (`-XDerivingVia'). Fixes #18130".

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30272412 by Artem Pelenitsyn at 2020-05-04T13:19:59-04:00
Remove custom ExceptionMonad class (#18075) (updating haddock submodule accordingly)

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b9f7c08f by jneira at 2020-05-04T13:20:37-04:00
Remove unused hs-boot file

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1d8f80cd by Sylvain Henry at 2020-05-05T03:22:46-04:00
Remove references to -package-key

* remove references to `-package-key` which has been removed in 2016
  (240ddd7c39536776e955e881d709bbb039b48513)

* remove support for `-this-package-key` which has been deprecated at the
  same time

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7bc3a65b by Sylvain Henry at 2020-05-05T03:23:31-04:00
Remove SpecConstrAnnotation (#13681)

This has been deprecated since 2013. Use GHC.Types.SPEC instead.

Make GHC.Exts "not-home" for haddock

Metric Decrease:
   haddock.base

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3c862f63 by DenisFrezzato at 2020-05-05T03:24:15-04:00
Fix Haskell98 short description in documentation

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2420c555 by Ryan Scott at 2020-05-05T03:24:53-04:00
Add regression tests for #16244, #16245, #16758

Commit e3c374cc5bd7eb49649b9f507f9f7740697e3f70 ended up
fixing quite a few bugs:

* This commit fixes #16244 completely. A regression test has been
  added.
* This commit fixes one program from #16245. (The program in
  https://gitlab.haskell.org/ghc/ghc/issues/16245#note_211369 still
  panics, and the program in
  https://gitlab.haskell.org/ghc/ghc/issues/16245#note_211400 still
  loops infinitely.) A regression test has been added for this
  program.
* This commit fixes #16758. Accordingly, this patch removes the
  `expect_broken` label from the `T16758` test case, moves it from
  `should_compile` to `should_fail` (as it should produce an error
  message), and checks in the expected stderr.

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40c71c2c by Sylvain Henry at 2020-05-05T03:25:31-04:00
Fix colorized error messages (#18128)

In b3df9e780fb2f5658412c644849cd0f1e6f50331 I broke colorized messages
by using "dump" style instead of "user" style. This commits fixes it.

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7ab6ab09 by Richard Eisenberg at 2020-05-06T04:39:32-04:00
Refactor hole constraints.

Previously, holes (both expression holes / out of scope variables and
partial-type-signature wildcards) were emitted as *constraints* via
the CHoleCan constructor. While this worked fine for error reporting,
there was a fair amount of faff in keeping these constraints in line.
In particular, and unlike other constraints, we could never change
a CHoleCan to become CNonCanonical. In addition:
 * the "predicate" of a CHoleCan constraint was really the type
   of the hole, which is not a predicate at all
 * type-level holes (partial type signature wildcards) carried
   evidence, which was never used
 * tcNormalise (used in the pattern-match checker) had to create
   a hole constraint just to extract it again; it was quite messy

The new approach is to record holes directly in WantedConstraints.
It flows much more nicely now.

Along the way, I did some cleaning up of commentary in
GHC.Tc.Errors.Hole, which I had a hard time understanding.

This was instigated by a future patch that will refactor
the way predicates are handled. The fact that CHoleCan's
"predicate" wasn't really a predicate is incompatible with
that future patch.

No test case, because this is meant to be purely internal.

It turns out that this change improves the performance of
the pattern-match checker, likely because fewer constraints
are sloshing about in tcNormalise. I have not investigated
deeply, but an improvement is not a surprise here:

-------------------------
Metric Decrease:
    PmSeriesG
-------------------------

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420b957d by Ben Gamari at 2020-05-06T04:40:08-04:00
rts: Zero block flags with -DZ

Block flags are very useful for determining the state of a block.
However, some block allocator users don't touch them, leading to
misleading values. Ensure that we zero then when zero-on-gc is set. This
is safe and makes the flags more useful during debugging.

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740b3b8d by Ben Gamari at 2020-05-06T04:40:08-04:00
nonmoving: Fix incorrect failed_to_evac value during deadlock gc

Previously we would incorrectly set the failed_to_evac flag if we
evacuated a value due to a deadlock GC. This would cause us to mark more
things as dirty than strictly necessary. It also turned up a nasty but
which I will fix next.

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b2d72c75 by Ben Gamari at 2020-05-06T04:40:08-04:00
nonmoving: Fix handling of dirty objects

Previously we (incorrectly) relied on failed_to_evac to be "precise".
That is, we expected it to only be true if *all* of an object's fields
lived outside of the non-moving heap. However, does not match the
behavior of failed_to_evac, which is true if *any* of the object's
fields weren't promoted (meaning that some others *may* live in the
non-moving heap).

This is problematic as we skip the non-moving write barrier for dirty
objects (which we can only safely do if *all* fields point outside of
the non-moving heap).

Clearly this arises due to a fundamental difference in the behavior
expected of failed_to_evac in the moving and non-moving collector.
e.g., in the moving collector it is always safe to conservatively say
failed_to_evac=true whereas in the non-moving collector the safe value
is false.

This issue went unnoticed as I never wrote down the dirtiness
invariant enforced by the non-moving collector. We now define this
invariant as

    An object being marked as dirty implies that all of its fields are
    on the mark queue (or, equivalently, update remembered set).

To maintain this invariant we teach nonmovingScavengeOne to push the
fields of objects which we fail to evacuate to the update remembered
set. This is a simple and reasonably cheap solution and avoids the
complexity and fragility that other, more strict alternative invariants
would require.

All of this is described in a new Note, Note [Dirty flags in the
non-moving collector] in NonMoving.c.

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9f3e6884 by Zubin Duggal at 2020-05-06T04:41:08-04:00
Allow atomic update of NameCache in readHieFile

The situation arises in ghcide where multiple different threads may need to
update the name cache, therefore with the older interface it could happen
that you start reading a hie file with name cache A and produce name cache
A + B, but another thread in the meantime updated the namecache to A +
C. Therefore if you write the new namecache you will lose the A' updates
from the second thread.

Updates haddock submodule

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edec6a6c by Ryan Scott at 2020-05-06T04:41:57-04:00
Make isTauTy detect higher-rank contexts

Previously, `isTauTy` would only detect higher-rank `forall`s, not
higher-rank contexts, which led to some minor bugs observed
in #18127. Easily fixed by adding a case for
`(FunTy InvisArg _ _)`.

Fixes #18127.

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a95e7fe0 by Ömer Sinan Ağacan at 2020-05-06T04:42:39-04:00
ELF linker: increment curSymbol after filling in fields of current entry

The bug was introduced in a8b7cef4d45 which added a field to the
`symbols` array elements and then updated this code incorrectly:

    - oc->symbols[curSymbol++] = nm;
    + oc->symbols[curSymbol++].name = nm;
    + oc->symbols[curSymbol].addr = symbol->addr;

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cab1871a by Sylvain Henry at 2020-05-06T04:43:21-04:00
Move LeadingUnderscore into Platform (#17957)

Avoid direct use of DynFlags to know if symbols must be prefixed by an
underscore.

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94e7c563 by Sylvain Henry at 2020-05-06T04:43:21-04:00
Don't use DynFlags in showLinkerState (#17957)

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9afd9251 by Ryan Scott at 2020-05-06T04:43:58-04:00
Refactoring: Use bindSigTyVarsFV in rnMethodBinds

`rnMethodBinds` was explicitly using `xoptM` to determine if
`ScopedTypeVariables` is enabled before bringing type variables
bound by the class/instance header into scope. However, this `xoptM`
logic is already performed by the `bindSigTyVarsFV` function. This
patch uses `bindSigTyVarsFV` in `rnMethodBinds` to reduce the number
of places where we need to consult if `ScopedTypeVariables` is on.

This is purely refactoring, and there should be no user-visible
change in behavior.

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6f6d72b2 by Brian Foley at 2020-05-08T15:29:25-04:00
Remove further dead code found by a simple Python script.

Avoid removing some functions that are part of an API even
though they're not used in-tree at the moment.

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78bf8bf9 by Julien Debon at 2020-05-08T15:29:28-04:00
Add doc examples for Bifoldable

See #17929

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66f0a847 by Julien Debon at 2020-05-08T15:29:29-04:00
doc (Bitraversable): Add examples to Bitraversable

* Add examples to Data.Bitraversable
* Fix formatting for (,) in Bitraversable and Bifoldable
* Fix mistake on bimapAccumR documentation

See #17929

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9749fe12 by Baldur Blöndal at 2020-05-08T15:29:32-04:00
Specify kind variables for inferred kinds in base.

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4e9aef9e by John Ericson at 2020-05-08T15:29:36-04:00
HsSigWcTypeScoping: Pull in documentation from stray location

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f4d5c6df by John Ericson at 2020-05-08T15:29:36-04:00
Rename local `real_fvs` to `implicit_vs`

It doesn't make sense to call the "free" variables we are about to
implicitly bind the real ones.

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20570b4b by John Ericson at 2020-05-08T15:29:36-04:00
A few tiny style nits with renaming

 - Use case rather than guards that repeatedly scrutenize same thing.

 - No need for view pattern when `L` is fine.

 - Use type synnonym to convey the intent like elsewhere.

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09ac8de5 by John Ericson at 2020-05-08T15:29:36-04:00
Add `forAllOrNothing` function with note

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bb35c0e5 by Joseph C. Sible at 2020-05-08T15:29:40-04:00
Document lawlessness of Ap's Num instance
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cdd229ff by Joseph C. Sible at 2020-05-08T15:29:40-04:00
Apply suggestion to libraries/base/Data/Monoid.hs
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926d2aab by Joseph C. Sible at 2020-05-08T15:29:40-04:00
Apply more suggestions from Simon Jakobi
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7a763cff by Adam Gundry at 2020-05-08T15:29:41-04:00
Reject all duplicate declarations involving DuplicateRecordFields (fixes #17965)

This fixes a bug that resulted in some programs being accepted that used the same
identifier as a field label and another declaration, depending on the order they
appeared in the source code.

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88e3c815 by Simon Peyton Jones at 2020-05-08T15:29:41-04:00
Fix specialisation for DFuns

When specialising a DFun we must take care to saturate the
unfolding.  See Note [Specialising DFuns] in Specialise.

Fixes #18120

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86c77b36 by Greg Steuck at 2020-05-08T15:29:45-04:00
Remove unused SEGMENT_PROT_RWX

It's been unused for a year and is problematic on any OS which
requires W^X for security.

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202269ec by Ben Gamari at 2020-05-09T15:28:04-04:00
GHC.Cmm.Opt: Handle MO_XX_Conv

This MachOp was introduced by 2c959a1894311e59cd2fd469c1967491c1e488f3
but a wildcard match in cmmMachOpFoldM hid the fact that it wasn't
handled. Ideally we would eliminate the match but this appears to be a
larger task.

Fixes #18141.

- - - - -

30 changed files:

- compiler/GHC.hs
- compiler/GHC/Cmm/CLabel.hs
- compiler/GHC/Cmm/Opt.hs
- compiler/GHC/Cmm/Pipeline.hs
- compiler/GHC/Cmm/Utils.hs
- compiler/GHC/CmmToAsm.hs
- compiler/GHC/CmmToAsm/PPC/Cond.hs
- compiler/GHC/CmmToAsm/SPARC/Cond.hs
- compiler/GHC/CmmToAsm/X86/Cond.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Opt/Driver.hs
- compiler/GHC/Core/Opt/Monad.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/Specialise.hs
- compiler/GHC/Core/Ppr.hs
- compiler/GHC/Core/Rules.hs
- compiler/GHC/Core/SimpleOpt.hs
- compiler/GHC/Core/TyCo/Ppr.hs
- compiler/GHC/Core/TyCon.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/Data/IOEnv.hs
- compiler/GHC/Driver/Backpack.hs
- compiler/GHC/Driver/CodeOutput.hs
- compiler/GHC/Driver/Finder.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Make.hs
- compiler/GHC/Driver/Monad.hs

The diff was not included because it is too large.

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