[Git][ghc/ghc][wip/perform-blocking-gc] 910 commits: rts: Teach getNumProcessors to return available processors

Ben Gamari gitlab at gitlab.haskell.org
Sun Nov 1 18:57:30 UTC 2020



Ben Gamari pushed to branch wip/perform-blocking-gc at Glasgow Haskell Compiler / GHC


Commits:
4413828b by Ben Gamari at 2020-05-30T06:07:31-04:00
rts: Teach getNumProcessors to return available processors

Previously we would report the number of physical processors, which
can be quite wrong in a containerized setting. Now we rather return how
many processors are in our affinity mask when possible.

I also refactored the code to prefer platform-specific since this will
report logical CPUs instead of physical (using
`machdep.cpu.thread_count` on Darwin and `cpuset_getaffinity` on FreeBSD).

Fixes #14781.

- - - - -
1449435c by Ben Gamari at 2020-05-30T06:07:31-04:00
users-guide: Note change in getNumProcessors in users guide

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3d960169 by Ben Gamari at 2020-05-30T06:07:31-04:00
rts: Drop compatibility shims for Windows Vista

We can now assume that the thread and processor group interfaces are
available.

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7f8f948c by Peter Trommler at 2020-05-30T06:08:07-04:00
PPC NCG: Fix .size directive on powerpc64 ELF v1

Thanks to Sergei Trofimovich for pointing out the issue.

Fixes #18237

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7c555b05 by Andreas Klebinger at 2020-05-30T06:08:43-04:00
Optimize GHC.Utils.Monad.

Many functions in this module are recursive and as such are marked
loop breakers. Which means they are unlikely to get an unfolding.

This is *bad*. We always want to specialize them to specific Monads.
Which requires a visible unfolding at the use site.

I rewrote the recursive ones from:

    foo f x = ... foo x' ...

to

    foo f x = go x
      where
        go x = ...

As well as giving some pragmas to make all of them available
for specialization.

The end result is a reduction of allocations of about -1.4% for
nofib/spectral/simple/Main.hs when compiled with `-O`.

-------------------------
Metric Decrease:
    T12425
    T14683
    T5631
    T9233
    T9675
    T9961
    WWRec
-------------------------

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8b1cb5df by Ben Gamari at 2020-05-30T06:09:20-04:00
Windows: Bump Windows toolchain to 0.2

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6947231a by Zubin Duggal at 2020-05-30T06:10:02-04:00
Simplify contexts in GHC.Iface.Ext.Ast

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2ee4f36c by Daniel Gröber at 2020-06-01T06:32:56-04:00
Cleanup OVERWRITING_CLOSURE logic

The code is just more confusing than it needs to be. We don't need to mix
the threaded check with the ldv profiling check since ldv's init already
checks for this. Hence they can be two separate checks. Taking the sanity
checking into account is also cleaner via DebugFlags.sanity. No need for
checking the DEBUG define.

The ZERO_SLOP_FOR_LDV_PROF and ZERO_SLOP_FOR_SANITY_CHECK definitions the
old code had also make things a lot more opaque IMO so I removed those.

- - - - -
6159559b by Daniel Gröber at 2020-06-01T06:32:56-04:00
Fix OVERWRITING_CLOSURE assuming closures are not inherently used

The new ASSERT in LDV_recordDead() was being tripped up by MVars when
removeFromMVarBlockedQueue() calls OVERWRITING_CLOSURE() via
OVERWRITE_INFO().

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38992085 by Daniel Gröber at 2020-06-01T06:32:56-04:00
Always zero shrunk mutable array slop when profiling

When shrinking arrays in the profiling way we currently don't always zero
the leftover slop. This means we can't traverse such closures in the heap
profiler. The old Note [zeroing slop] and #8402 have some rationale for why
this is so but I belive the reasoning doesn't apply to mutable
closures. There users already have to ensure multiple threads don't step on
each other's toes so zeroing should be safe.

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b0c1f2a6 by Ben Gamari at 2020-06-01T06:33:37-04:00
testsuite: Add test for #18151

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9a99a178 by Ben Gamari at 2020-06-01T06:33:37-04:00
testsuite: Add test for desugaring of PostfixOperators

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2b89ca5b by Ben Gamari at 2020-06-01T06:33:37-04:00
HsToCore: Eta expand left sections

Strangely, the comment next to this code already alluded to the fact
that even simply eta-expanding will sacrifice laziness. It's quite
unclear how we regressed so far.

See #18151.

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d412d7a3 by Kirill Elagin at 2020-06-01T06:34:21-04:00
Winferred-safe-imports: Do not exit with error

Currently, when -Winferred-safe-imports is enabled, even when it is not
turned into an error, the compiler will still exit with exit code 1 if
this warning was emitted.

Make sure it is really treated as a warning.

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f945eea5 by Ben Gamari at 2020-06-01T06:34:58-04:00
nonmoving: Optimise log2_ceil

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aab606e4 by Bodigrim at 2020-06-01T06:35:36-04:00
Clarify description of fromListN
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7e5220e2 by Bodigrim at 2020-06-01T06:35:36-04:00
Apply suggestion to libraries/base/GHC/Exts.hs
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f3fb1ce9 by fendor at 2020-06-01T06:36:18-04:00
Add `isInScope` check to `lintCoercion`

Mirrors the behaviour of `lintType`.

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5ac4d946 by fendor at 2020-06-01T06:36:18-04:00
Lint rhs of IfaceRule

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1cef6126 by Jeremy Schlatter at 2020-06-01T06:37:00-04:00
Fix wording in documentation

The duplicate "orphan instance" phrase here doesn't make sense, and was
probably an accident.

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5aaf08f2 by Takenobu Tani at 2020-06-01T06:37:43-04:00
configure: Modify aclocal.m4 according to new module hierarchy

This patch updates file paths according to new module hierarchy [1]:

* Rename:
  * compiler/GHC/Parser.hs       <= compiler/parser/Parser.hs
  * compiler/GHC/Parser/Lexer.hs <= compiler/Parser/Lexer.hs

* Add:
  * compiler/GHC/Cmm/Lexer.hs

[1]: https://gitlab.haskell.org/ghc/ghc/-/wikis/Make-GHC-codebase-more-modular

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15857ad8 by Ben Gamari at 2020-06-01T06:38:26-04:00
testsuite: Don't fail if we can't unlink __symlink_test

Afterall, it's possible we were unable to create it due to lack of
symlink permission.

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4a7229ef by Ben Gamari at 2020-06-01T06:38:26-04:00
testsuite: Refactor ghostscript detection

Tamar reported that he saw crashes due to unhandled exceptions.

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2ab37eaf by Ben Gamari at 2020-06-01T06:38:26-04:00
testsuite/perf_notes: Fix ill-typed assignments

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e45d5b66 by Ben Gamari at 2020-06-01T06:38:26-04:00
testsuite/testutil: Fix bytes/str mismatch

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7002d0cb by Ben Gamari at 2020-06-01T06:38:26-04:00
testsuite: Work around spurious mypy failure

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11390e3a by Takenobu Tani at 2020-06-01T06:39:05-04:00
Clean up file paths for new module hierarchy

This updates comments only.
This patch replaces file references according to new module hierarchy.

See also:
* https://gitlab.haskell.org/ghc/ghc/-/wikis/Make-GHC-codebase-more-modular
* https://gitlab.haskell.org/ghc/ghc/issues/13009

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8f2e5732 by Takenobu Tani at 2020-06-01T06:39:05-04:00
Modify file paths to module paths for new module hierarchy

This updates comments only.

This patch replaces module references according to new module
hierarchy [1][2].

For files under the `compiler/` directory, I replace them as
module paths instead of file paths. For instance,
`GHC.Unit.State` instead of `compiler/GHC/Unit/State.hs` [3].

For current and future haddock's markup, this patch encloses
the module name with "" [4].

[1]: https://gitlab.haskell.org/ghc/ghc/-/wikis/Make-GHC-codebase-more-modular
[2]: https://gitlab.haskell.org/ghc/ghc/issues/13009
[3]: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/3375#note_276613
[4]: https://haskell-haddock.readthedocs.io/en/latest/markup.html#linking-to-modules

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68b71c4a by Tom Ellis at 2020-06-01T06:39:55-04:00
Rename the singleton tuple GHC.Tuple.Unit to GHC.Tuple.Solo

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95da76c2 by Sylvain Henry at 2020-06-01T06:40:41-04:00
Hadrian: fix binary-dist target for cross-compilation

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730fcd54 by Vladislav Zavialov at 2020-06-01T06:41:18-04:00
Improve parser error messages for the @-operator

Since GHC diverges from the Haskell Report by allowing the user
to define (@) as an infix operator, we better give a good
error message when the user does so unintentionally.

In general, this is rather hard to do, as some failures will be
discovered only in the renamer or the type checker:

	x :: (Integer, Integer)
	x @ (a, b) = (1, 2)

This patch does *not* address this general case.

However, it gives much better error messages when the binding
is not syntactically valid:

	pairs xs @ (_:xs') = zip xs xs'

Before this patch, the error message was rather puzzling:

	<interactive>:1:1: error: Parse error in pattern: pairs

After this patch, the error message includes a hint:

	<interactive>:1:1: error:
	    Parse error in pattern: pairs
	    In a function binding for the ‘@’ operator.
	    Perhaps you meant an as-pattern, which must not be surrounded by whitespace

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0fde5377 by Vladislav Zavialov at 2020-06-01T06:41:18-04:00
Improve parser error messages for TypeApplications

With this patch, we always parse  f @t  as a type application,
thereby producing better error messages.

This steals two syntactic forms:

* Prefix form of the @-operator in expressions. Since the @-operator is
  a divergence from the Haskell Report anyway, this is not a major loss.

* Prefix form of @-patterns. Since we are stealing loose infix form
  anyway, might as well sacrifice the prefix form for the sake of much
  better error messages.

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c68e7e1e by Vladislav Zavialov at 2020-06-01T06:41:18-04:00
Improve parser error messages for TemplateHaskellQuotes

While [e| |], [t| |], [d| |], and so on, steal syntax from list
comprehensions, [| |] and [|| ||] do not steal any syntax.

Thus we can improve error messages by always accepting them in the
lexer. Turns out the renamer already performs necessary validation.

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120aedbd by Ben Gamari at 2020-06-01T16:07:02-04:00
gitlab-ci: Disable use of ld.lld on ARMv7

It turns out that lld non-deterministically fails on ARMv7. I suspect
this may be due to the a kernel regression as this only started
happening when we upgraded to 5.4. Nevertheless, easily avoided by
simply sticking with gold.

Works around #18280.

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d6279ff0 by Ben Gamari at 2020-06-02T13:03:30-04:00
gitlab-ci: Ensure that workaround for #18280 applies to bindisttest

We need to ensure that the `configure` flags working around #18280 are
propagated to the bindisttest `configure` as well.

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cb5c31b5 by Ben Gamari at 2020-06-03T17:55:04-04:00
gitlab-ci: Allow ARMv7 job to fail

Due to #18298.

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32a4ae90 by John Ericson at 2020-06-04T04:34:42-04:00
Clean up boot vs non-boot disambiguating types

We often have (ModuleName, Bool) or (Module, Bool) pairs for "extended"
module names (without or with a unit id) disambiguating boot and normal
modules. We think this is important enough across the compiler that it
deserves a new nominal product type. We do this with synnoyms and a
functor named with a `Gen` prefix, matching other newly created
definitions.

It was also requested that we keep custom `IsBoot` / `NotBoot` sum type.
So we have it too. This means changing many the many bools to use that
instead.

Updates `haddock` submodule.

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c05756cd by Niklas Hambüchen at 2020-06-04T04:35:24-04:00
docs: Add more details on InterruptibleFFI.

Details from https://gitlab.haskell.org/ghc/ghc/issues/8684
and https://github.com/takano-akio/filelock/pull/7#discussion_r280332430

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1b975aed by Andrew Martin at 2020-06-04T04:36:03-04:00
Allow finalizeForeignPtr to be called on FinalPtr/PlainPtr.

MR 2165 (commit 49301ad6226d9a83d110bee8c419615dd94f5ded) regressed
finalizeForeignPtr by throwing exceptions when PlainPtr was encounterd.
This regression did not make it into a release of GHC. Here, the
original behavior is restored, and FinalPtr is given the same treatment
as PlainPtr.

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2bd3929a by Luke Lau at 2020-06-04T04:36:41-04:00
Fix documentation on type families not being extracted

It looks like the location of the Names used for CoAxioms on type
families are now located at their type constructors. Previously, Docs.hs
thought the Names were located in the RHS, so the RealSrcSpan in the
instanceMap and getInstLoc didn't match up. Fixes #18241

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6735b9d9 by Ben Gamari at 2020-06-04T04:37:21-04:00
GHC.Hs.Instances: Compile with -O0

This module contains exclusively Data instances, which are going to be
slow no matter what we do. Furthermore, they are incredibly slow to
compile with optimisation (see #9557). Consequently we compile this with
-O0.  See #18254.

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c330331a by nineonine at 2020-06-04T04:37:59-04:00
Add test for #17669

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cab684f0 by Ben Gamari at 2020-06-04T04:38:36-04:00
rts: Add Windows-specific implementation of rtsSleep

Previously we would use the POSIX path, which uses `nanosleep`. However,
it turns out that `nanosleep` is provided by `libpthread` on Windows. In
general we don't want to incur such a dependency. Avoid this by simply
using `Sleep` on Windows.

Fixes #18272.

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ad44b504 by Ben Gamari at 2020-06-04T04:38:36-04:00
compiler: Disable use of process jobs with process < 1.6.9

Due to #17926.

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6a4098a4 by Moritz Angermann at 2020-06-04T04:55:51-04:00
[linker] Adds void printLoadedObjects(void);

This allows us to dump in-memory object code locations for debugging.

Fixup printLoadedObjects prototype

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af5e3a88 by Artem Pelenitsyn at 2020-06-05T03:18:49-04:00
base: fix sign confusion in log1mexp implementation (fix #17125)

author: claude (https://gitlab.haskell.org/trac-claude)

The correct threshold for log1mexp is -(log 2) with the current specification
of log1mexp. This change improves accuracy for large negative inputs.

To avoid code duplication, a small helper function is added;
it isn't the default implementation in Floating because it needs Ord.

This patch does nothing to address that the Haskell specification is
different from that in common use in other languages.

- - - - -
2b792fac by Simon Peyton Jones at 2020-06-05T09:27:50-04:00
Simple subsumption

This patch simplifies GHC to use simple subsumption.
  Ticket #17775

Implements GHC proposal #287
   https://github.com/ghc-proposals/ghc-proposals/blob/master/
   proposals/0287-simplify-subsumption.rst

All the motivation is described there; I will not repeat it here.
The implementation payload:
 * tcSubType and friends become noticably simpler, because it no
   longer uses eta-expansion when checking subsumption.
 * No deeplyInstantiate or deeplySkolemise

That in turn means that some tests fail, by design; they can all
be fixed by eta expansion.  There is a list of such changes below.

Implementing the patch led me into a variety of sticky corners, so
the patch includes several othe changes, some quite significant:

* I made String wired-in, so that
    "foo" :: String   rather than
    "foo" :: [Char]
  This improves error messages, and fixes #15679

* The pattern match checker relies on knowing about in-scope equality
  constraints, andd adds them to the desugarer's environment using
  addTyCsDs.  But the co_fn in a FunBind was missed, and for some reason
  simple-subsumption ends up with dictionaries there. So I added a
  call to addTyCsDs.  This is really part of #18049.

* I moved the ic_telescope field out of Implication and into
  ForAllSkol instead.  This is a nice win; just expresses the code
  much better.

* There was a bug in GHC.Tc.TyCl.Instance.tcDataFamInstHeader.
  We called checkDataKindSig inside tc_kind_sig, /before/
  solveEqualities and zonking.  Obviously wrong, easily fixed.

* solveLocalEqualitiesX: there was a whole mess in here, around
  failing fast enough.  I discovered a bad latent bug where we
  could successfully kind-check a type signature, and use it,
  but have unsolved constraints that could fill in coercion
  holes in that signature --  aargh.

  It's all explained in Note [Failure in local type signatures]
  in GHC.Tc.Solver. Much better now.

* I fixed a serious bug in anonymous type holes. IN
    f :: Int -> (forall a. a -> _) -> Int
  that "_" should be a unification variable at the /outer/
  level; it cannot be instantiated to 'a'.  This was plain
  wrong.  New fields mode_lvl and mode_holes in TcTyMode,
  and auxiliary data type GHC.Tc.Gen.HsType.HoleMode.

  This fixes #16292, but makes no progress towards the more
  ambitious #16082

* I got sucked into an enormous refactoring of the reporting of
  equality errors in GHC.Tc.Errors, especially in
      mkEqErr1
      mkTyVarEqErr
      misMatchMsg
      misMatchMsgOrCND
  In particular, the very tricky mkExpectedActualMsg function
  is gone.

  It took me a full day.  But the result is far easier to understand.
  (Still not easy!)  This led to various minor improvements in error
  output, and an enormous number of test-case error wibbles.

  One particular point: for occurs-check errors I now just say
     Can't match 'a' against '[a]'
  rather than using the intimidating language of "occurs check".

* Pretty-printing AbsBinds

Tests review

* Eta expansions
   T11305: one eta expansion
   T12082: one eta expansion (undefined)
   T13585a: one eta expansion
   T3102:  one eta expansion
   T3692:  two eta expansions (tricky)
   T2239:  two eta expansions
   T16473: one eta
   determ004: two eta expansions (undefined)
   annfail06: two eta (undefined)
   T17923: four eta expansions (a strange program indeed!)
   tcrun035: one eta expansion

* Ambiguity check at higher rank.  Now that we have simple
  subsumption, a type like
     f :: (forall a. Eq a => Int) -> Int
  is no longer ambiguous, because we could write
     g :: (forall a. Eq a => Int) -> Int
     g = f
  and it'd typecheck just fine.  But f's type is a bit
  suspicious, and we might want to consider making the
  ambiguity check do a check on each sub-term.  Meanwhile,
  these tests are accepted, whereas they were previously
  rejected as ambiguous:
     T7220a
     T15438
     T10503
     T9222

* Some more interesting error message wibbles
   T13381: Fine: one error (Int ~ Exp Int)
           rather than two (Int ~ Exp Int, Exp Int ~ Int)
   T9834:  Small change in error (improvement)
   T10619: Improved
   T2414:  Small change, due to order of unification, fine
   T2534:  A very simple case in which a change of unification order
           means we get tow unsolved constraints instead of one
   tc211: bizarre impredicative tests; just accept this for now

Updates Cabal and haddock submodules.

Metric Increase:
  T12150
  T12234
  T5837
  haddock.base
Metric Decrease:
  haddock.compiler
  haddock.Cabal
  haddock.base

Merge note: This appears to break the
`UnliftedNewtypesDifficultUnification` test. It has been marked as
broken in the interest of merging.

(cherry picked from commit 66b7b195cb3dce93ed5078b80bf568efae904cc5)

- - - - -
2dff8141 by Ryan Scott at 2020-06-05T14:21:24-04:00
Simplify bindLHsTyVarBndrs and bindHsQTyVars

Both `bindLHsTyVarBndrs` and `bindHsQTyVars` take two separate
`Maybe` arguments, which I find terribly confusing. Thankfully, it's
possible to remove one `Maybe` argument from each of these functions,
which this patch accomplishes:

* `bindHsQTyVars` takes a `Maybe SDoc` argument, which is `Just` if
  GHC should warn about any of the quantified type variables going
  unused. However, every call site uses `Nothing` in practice. This
  makes sense, since it doesn't really make sense to warn about
  unused type variables bound by an `LHsQTyVars`. For instance, you
  wouldn't warn about the `a` in `data Proxy a = Proxy` going unused.

  As a result, I simply remove this `Maybe SDoc` argument altogether.
* `bindLHsTyVarBndrs` also takes a `Maybe SDoc` argument for the same
  reasons that `bindHsQTyVars` took one. To make things more
  confusing, however, `bindLHsTyVarBndrs` also takes a separate
  `HsDocContext` argument, which is pretty-printed (to an `SDoc`) in
  warnings and error messages.

  In practice, the `Maybe SDoc` and the `HsDocContext` often contain
  the same text. See the call sites for `bindLHsTyVarBndrs` in
  `rnFamInstEqn` and `rnConDecl`, for instance. There are only a
  handful of call sites where the text differs between the
  `Maybe SDoc` and `HsDocContext` arguments:

  * In `rnHsRuleDecl`, where the `Maybe SDoc` says "`In the rule`"
    and the `HsDocContext` says "`In the transformation rule`".
  * In `rnHsTyKi`/`rn_ty`, where the `Maybe SDoc` says
    "`In the type`" but the `HsDocContext` is inhereted from the
    surrounding context (e.g., if `rnHsTyKi` were called on a
    top-level type signature, the `HsDocContext` would be
    "`In the type signature`" instead)

  In both cases, warnings/error messages arguably _improve_ by
  unifying making the `Maybe SDoc`'s text match that of the
  `HsDocContext`. As a result, I decided to remove the `Maybe SDoc`
  argument to `bindLHsTyVarBndrs` entirely and simply reuse the text
  from the `HsDocContext`. (I decided to change the phrase
  "transformation rule" to "rewrite rule" while I was in the area.)

  The `Maybe SDoc` argument has one other purpose: signaling when to
  emit "`Unused quantified type variable`" warnings. To recover this
  functionality, I replaced the `Maybe SDoc` argument with a
  boolean-like `WarnUnusedForalls` argument. The only
  `bindLHsTyVarBndrs` call site that chooses _not_ to emit these
  warnings in `bindHsQTyVars`.

- - - - -
e372331b by Ben Gamari at 2020-06-07T08:46:41-04:00
hadrian: Add missing deriveConstants dependency on ghcplatform.h

deriveConstants wants to compile C sources which #include PosixSource.h,
which itself #includes ghcplatform.h. Make sure that Hadrian knows
about this dependency.

Fixes #18290.

- - - - -
b022051a by Moritz Angermann at 2020-06-07T08:46:42-04:00
ghc-prim needs to depend on libc and libm

libm is just an empty shell on musl, and all the math functions are contained in
libc.

- - - - -
6dae6548 by Moritz Angermann at 2020-06-07T08:46:42-04:00
Disable DLL loading if without system linker

Some platforms (musl, aarch64) do not have a working dynamic linker
implemented in the libc, even though we might see dlopen.  It will
ultimately just return that this is not supported.  Hence we'll add
a flag to the compiler to flat our disable loading dlls.  This is
needed as we will otherwise try to load the shared library even
if this will subsequently fail.  At that point we have given up
looking for static options though.

- - - - -
4a158ffc by Moritz Angermann at 2020-06-07T08:46:43-04:00
Range is actually +/-2^32, not +/-2^31

See also: https://static.docs.arm.com/ihi0056/g/aaelf64.pdf

- - - - -
f1bfb806 by Ben Gamari at 2020-06-07T10:49:30-04:00
OccurAnal: Avoid exponential behavior due to where clauses

Previously the `Var` case of `occAnalApp` could in some cases (namely
in the case of `runRW#` applications) call `occAnalRhs` two. In the case
of nested `runRW#`s this results in exponential complexity. In some
cases the compilation time that resulted would be very long indeed
(see #18296).

Fixes #18296.

Metric Decrease:
    T9961
    T12150
    T12234

- - - - -
9b607671 by Takenobu Tani at 2020-06-09T08:05:46-04:00
Add link to GHC's wiki in the GHC API header

This adds a URL to point to GHC's wiki in the GHC API header.
Newcomers could easily find more information from the GHC API's
web like [1].

[1]: Current version, https://ghc.gitlab.haskell.org/ghc/doc/libraries/ghc-8.11.0.20200604/index.html

[skip ci]

- - - - -
72c7fe9a by Ryan Scott at 2020-06-09T08:06:24-04:00
Make GADT constructors adhere to the forall-or-nothing rule properly

Issue #18191 revealed that the types of GADT constructors don't quite
adhere to the `forall`-or-nothing rule. This patch serves to clean up
this sad state of affairs somewhat. The main change is not in the
code itself, but in the documentation, as this patch introduces two
sections to the GHC User's Guide:

* A "Formal syntax for GADTs" section that presents a BNF-style
  grammar for what is and isn't allowed in GADT constructor types.
  This mostly exists to codify GHC's existing behavior, but it also
  imposes a new restriction that addresses #18191: the outermost
  `forall` and/or context in a GADT constructor is not allowed to be
  surrounded by parentheses. Doing so would make these
  `forall`s/contexts nested, and GADTs do not support nested
  `forall`s/contexts at present.

* A "`forall`-or-nothing rule" section that describes exactly what
  the `forall`-or-nothing rule is all about. Surprisingly, there was
  no mention of this anywhere in the User's Guide up until now!

To adhere the new specification in the "Formal syntax for GADTs"
section of the User's Guide, the following code changes were made:

* A new function, `GHC.Hs.Type.splitLHsGADTPrefixTy`, was introduced.
  This is very much like `splitLHsSigmaTy`, except that it avoids
  splitting apart any parentheses, which can be syntactically
  significant for GADT types. See
  `Note [No nested foralls or contexts in GADT constructors]` in
  `GHC.Hs.Type`.

* `ConDeclGADTPrefixPs`, an extension constructor for `XConDecl`, was
  introduced so that `GHC.Parser.PostProcess.mkGadtDecl` can return
  it when given a prefix GADT constructor. Unlike `ConDeclGADT`,
  `ConDeclGADTPrefixPs` does not split the GADT type into its argument
  and result types, as this cannot be done until after the type is
  renamed (see `Note [GADT abstract syntax]` in `GHC.Hs.Decls` for why
  this is the case).

* `GHC.Renamer.Module.rnConDecl` now has an additional case for
  `ConDeclGADTPrefixPs` that (1) splits apart the full `LHsType` into
  its `forall`s, context, argument types, and result type, and
  (2) checks for nested `forall`s/contexts. Step (2) used to be
  performed the typechecker (in `GHC.Tc.TyCl.badDataConTyCon`) rather
  than the renamer, but now the relevant code from the typechecker
  can simply be deleted.

  One nice side effect of this change is that we are able to give a
  more accurate error message for GADT constructors that use visible
  dependent quantification (e.g., `MkFoo :: forall a -> a -> Foo a`),
  which improves the stderr in the `T16326_Fail6` test case.

Fixes #18191. Bumps the Haddock submodule.

- - - - -
a47e6442 by Ryan Scott at 2020-06-10T03:39:12-04:00
Always use rnImplicitBndrs to bring implicit tyvars into scope

This implements a first step towards #16762 by changing the renamer
to always use `rnImplicitBndrs` to bring implicitly bound type
variables into scope. The main change is in `rnFamInstEqn` and
`bindHsQTyVars`, which previously used _ad hoc_ methods of binding
their implicit tyvars.

There are a number of knock-on consequences:

* One of the reasons that `rnFamInstEqn` used an _ad hoc_ binding
  mechanism was to give more precise source locations in
  `-Wunused-type-patterns` warnings. (See
  https://gitlab.haskell.org/ghc/ghc/issues/16762#note_273343 for an
  example of this.) However, these warnings are actually a little
  _too_ precise, since implicitly bound type variables don't have
  exact binding sites like explicitly bound type variables do.
  A similar problem existed for
  "`Different names for the same type variable`" errors involving
  implicit tyvars bound by `bindHsQTyVars`.
  Therefore, we simply accept the less precise (but more accurate)
  source locations from `rnImplicitBndrs` in `rnFamInstEqn` and
  `bindHsQTyVars`. See
  `Note [Source locations for implicitly bound type variables]` in
  `GHC.Rename.HsType` for the full story.
* In order for `rnImplicitBndrs` to work in `rnFamInstEqn`, it needs
  to be able to look up names from the parent class (in the event
  that we are renaming an associated type family instance). As a
  result, `rnImplicitBndrs` now takes an argument of type
  `Maybe assoc`, which is `Just` in the event that a type family
  instance is associated with a class.
* Previously, GHC kept track of three type synonyms for free type
  variables in the renamer: `FreeKiTyVars`, `FreeKiTyVarsDups`
  (which are allowed to contain duplicates), and
  `FreeKiTyVarsNoDups` (which contain no duplicates). However, making
  is a distinction between `-Dups` and `-NoDups` is now pointless, as
  all code that returns `FreeKiTyVars{,Dups,NoDups}` will eventually
  end up being passed to `rnImplicitBndrs`, which removes duplicates.
  As a result, I decided to just get rid of `FreeKiTyVarsDups` and
  `FreeKiTyVarsNoDups`, leaving only `FreeKiTyVars`.
* The `bindLRdrNames` and `deleteBys` functions are now dead code, so
  I took the liberty of removing them.

- - - - -
24879129 by Takenobu Tani at 2020-06-10T03:39:59-04:00
Clarify leaf module names for new module hierarchy

This updates comments only.

This patch replaces leaf module names according to new module
hierarchy [1][2] as followings:

* Expand leaf names to easily find the module path:
  for instance, `Id.hs` to `GHC.Types.Id`.

* Modify leaf names according to new module hierarchy:
  for instance, `Convert.hs` to `GHC.ThToHs`.

* Fix typo:
  for instance, `GHC.Core.TyCo.Rep.hs` to `GHC.Core.TyCo.Rep`

See also !3375

[1]: https://gitlab.haskell.org/ghc/ghc/-/wikis/Make-GHC-codebase-more-modular
[2]: https://gitlab.haskell.org/ghc/ghc/issues/13009

- - - - -
92de9e25 by Ömer Sinan Ağacan at 2020-06-10T03:41:07-04:00
rts: Remove unused GET_ENTRY closure macro

This macro is not used and got broken in the meantime, as ENTRY_CODE was
deleted.

- - - - -
87102928 by Ömer Sinan Ağacan at 2020-06-10T03:41:50-04:00
Fix -fkeep-cafs flag name in users guide

- - - - -
ccd6843d by Shayne Fletcher at 2020-06-10T04:14:57-04:00
Expose impliedGFlags, impledOffGFlags, impliedXFlags

- - - - -
7a737e89 by Ömer Sinan Ağacan at 2020-06-10T04:14:58-04:00
Cross-module LambdaFormInfo passing

- Store LambdaFormInfos of exported Ids in interface files
- Use them in importing modules

This is for optimization purposes: if we know LambdaFormInfo of imported
Ids we can generate more efficient calling code, see `getCallMethod`.

Exporting (putting them in interface files or in ModDetails) and
importing (reading them from interface files) are both optional. We
don't assume known LambdaFormInfos anywhere and do not change how we
call Ids with unknown LambdaFormInfos.

Runtime, allocation, and residency numbers when building
Cabal-the-library (commit 0d4ee7ba3):

(Log and .hp files are in the MR: !2842)

|     | GHC HEAD | This patch | Diff           |
|-----|----------|------------|----------------|
| -O0 |  0:35.89 |    0:34.10 | -1.78s, -4.98% |
| -O1 |  2:24.01 |    2:23.62 | -0.39s, -0.27% |
| -O2 |  2:52.23 |    2:51.35 | -0.88s, -0.51% |

|     | GHC HEAD        | This patch      | Diff                       |
|-----|-----------------|-----------------|----------------------------|
| -O0 |  54,843,608,416 |  54,878,769,544 |  +35,161,128 bytes, +0.06% |
| -O1 | 227,136,076,400 | 227,569,045,168 | +432,968,768 bytes, +0.19% |
| -O2 | 266,147,063,296 | 266,749,643,440 | +602,580,144 bytes, +0.22% |

NOTE: Residency is measured with extra runtime args: `-i0 -h` which effectively
turn all GCs into major GCs, and do GC more often.

|     | GHC HEAD                   | This patch                   | Diff                       |
|-----|----------------------------|------------------------------|----------------------------|
| -O0 | 410,284,000 (910 samples)  | 411,745,008 (906 samples)    | +1,461,008 bytes, +0.35%   |
| -O1 | 928,580,856 (2109 samples) | 943,506,552 (2103 samples)   | +14,925,696 bytes, +1.60%  |
| -O2 | 993,951,352 (2549 samples) | 1,010,156,328 (2545 samples) | +16,204,9760 bytes, +1.63% |

NoFib results:

--------------------------------------------------------------------------------
        Program           Size    Allocs    Instrs     Reads    Writes
--------------------------------------------------------------------------------
             CS           0.0%      0.0%     +0.0%     +0.0%     +0.0%
            CSD           0.0%      0.0%      0.0%     +0.0%     +0.0%
             FS           0.0%      0.0%     +0.0%     +0.0%     +0.0%
              S           0.0%      0.0%     +0.0%     +0.0%     +0.0%
             VS           0.0%      0.0%     +0.0%     +0.0%     +0.0%
            VSD           0.0%      0.0%     +0.0%     +0.0%     +0.1%
            VSM           0.0%      0.0%     +0.0%     +0.0%     +0.0%
           anna           0.0%      0.0%     -0.3%     -0.8%     -0.0%
           ansi           0.0%      0.0%     -0.0%     -0.0%      0.0%
           atom           0.0%      0.0%     -0.0%     -0.0%      0.0%
         awards           0.0%      0.0%     -0.1%     -0.3%      0.0%
         banner           0.0%      0.0%     -0.0%     -0.0%     -0.0%
     bernouilli           0.0%      0.0%     -0.0%     -0.0%     -0.0%
   binary-trees           0.0%      0.0%     -0.0%     -0.0%     +0.0%
          boyer           0.0%      0.0%     -0.0%     -0.0%      0.0%
         boyer2           0.0%      0.0%     -0.0%     -0.0%      0.0%
           bspt           0.0%      0.0%     -0.0%     -0.2%      0.0%
      cacheprof           0.0%      0.0%     -0.1%     -0.4%     +0.0%
       calendar           0.0%      0.0%     -0.0%     -0.0%      0.0%
       cichelli           0.0%      0.0%     -0.9%     -2.4%      0.0%
        circsim           0.0%      0.0%     -0.0%     -0.0%      0.0%
       clausify           0.0%      0.0%     -0.1%     -0.3%      0.0%
  comp_lab_zift           0.0%      0.0%     -0.0%     -0.0%     +0.0%
       compress           0.0%      0.0%     -0.0%     -0.0%     -0.0%
      compress2           0.0%      0.0%     -0.0%     -0.0%      0.0%
    constraints           0.0%      0.0%     -0.1%     -0.2%     -0.0%
   cryptarithm1           0.0%      0.0%     -0.0%     -0.0%      0.0%
   cryptarithm2           0.0%      0.0%     -1.4%     -4.1%     -0.0%
            cse           0.0%      0.0%     -0.0%     -0.0%     -0.0%
   digits-of-e1           0.0%      0.0%     -0.0%     -0.0%     -0.0%
   digits-of-e2           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         dom-lt           0.0%      0.0%     -0.1%     -0.2%      0.0%
          eliza           0.0%      0.0%     -0.5%     -1.5%      0.0%
          event           0.0%      0.0%     -0.0%     -0.0%     -0.0%
    exact-reals           0.0%      0.0%     -0.1%     -0.3%     +0.0%
         exp3_8           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         expert           0.0%      0.0%     -0.3%     -1.0%     -0.0%
 fannkuch-redux           0.0%      0.0%     +0.0%     +0.0%     +0.0%
          fasta           0.0%      0.0%     -0.0%     -0.0%     +0.0%
            fem           0.0%      0.0%     -0.0%     -0.0%      0.0%
            fft           0.0%      0.0%     -0.0%     -0.0%      0.0%
           fft2           0.0%      0.0%     -0.0%     -0.0%      0.0%
       fibheaps           0.0%      0.0%     -0.0%     -0.0%     +0.0%
           fish           0.0%      0.0%      0.0%     -0.0%     +0.0%
          fluid           0.0%      0.0%     -0.4%     -1.2%     +0.0%
         fulsom           0.0%      0.0%     -0.0%     -0.0%      0.0%
         gamteb           0.0%      0.0%     -0.1%     -0.3%      0.0%
            gcd           0.0%      0.0%     -0.0%     -0.0%      0.0%
    gen_regexps           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         genfft           0.0%      0.0%     -0.0%     -0.0%      0.0%
             gg           0.0%      0.0%     -0.0%     -0.0%     +0.0%
           grep           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         hidden           0.0%      0.0%     -0.1%     -0.4%     -0.0%
            hpg           0.0%      0.0%     -0.2%     -0.5%     +0.0%
            ida           0.0%      0.0%     -0.0%     -0.0%     +0.0%
          infer           0.0%      0.0%     -0.3%     -0.8%     -0.0%
        integer           0.0%      0.0%     -0.0%     -0.0%     +0.0%
      integrate           0.0%      0.0%     -0.0%     -0.0%      0.0%
   k-nucleotide           0.0%      0.0%     -0.0%     -0.0%     +0.0%
          kahan           0.0%      0.0%     -0.0%     -0.0%     +0.0%
        knights           0.0%      0.0%     -2.2%     -5.4%      0.0%
         lambda           0.0%      0.0%     -0.6%     -1.8%      0.0%
     last-piece           0.0%      0.0%     -0.0%     -0.0%      0.0%
           lcss           0.0%      0.0%     -0.0%     -0.1%      0.0%
           life           0.0%      0.0%     -0.0%     -0.1%      0.0%
           lift           0.0%      0.0%     -0.2%     -0.6%     +0.0%
         linear           0.0%      0.0%     -0.0%     -0.0%     -0.0%
      listcompr           0.0%      0.0%     -0.0%     -0.0%      0.0%
       listcopy           0.0%      0.0%     -0.0%     -0.0%      0.0%
       maillist           0.0%      0.0%     -0.1%     -0.3%     +0.0%
         mandel           0.0%      0.0%     -0.0%     -0.0%      0.0%
        mandel2           0.0%      0.0%     -0.0%     -0.0%     -0.0%
           mate          +0.0%      0.0%     -0.0%     -0.0%     -0.0%
        minimax           0.0%      0.0%     -0.2%     -1.0%      0.0%
        mkhprog           0.0%      0.0%     -0.1%     -0.2%     -0.0%
     multiplier           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         n-body           0.0%      0.0%     -0.0%     -0.0%     +0.0%
       nucleic2           0.0%      0.0%     -0.1%     -0.2%      0.0%
           para           0.0%      0.0%     -0.0%     -0.0%     -0.0%
      paraffins           0.0%      0.0%     -0.0%     -0.0%      0.0%
         parser           0.0%      0.0%     -0.2%     -0.7%      0.0%
        parstof           0.0%      0.0%     -0.0%     -0.0%     +0.0%
            pic           0.0%      0.0%     -0.0%     -0.0%      0.0%
       pidigits           0.0%      0.0%     +0.0%     +0.0%     +0.0%
          power           0.0%      0.0%     -0.2%     -0.6%     +0.0%
         pretty           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         primes           0.0%      0.0%     -0.0%     -0.0%      0.0%
      primetest           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         prolog           0.0%      0.0%     -0.3%     -1.1%      0.0%
         puzzle           0.0%      0.0%     -0.0%     -0.0%      0.0%
         queens           0.0%      0.0%     -0.0%     -0.0%     +0.0%
        reptile           0.0%      0.0%     -0.0%     -0.0%      0.0%
reverse-complem           0.0%      0.0%     -0.0%     -0.0%     +0.0%
        rewrite           0.0%      0.0%     -0.7%     -2.5%     -0.0%
           rfib           0.0%      0.0%     -0.0%     -0.0%      0.0%
            rsa           0.0%      0.0%     -0.0%     -0.0%      0.0%
            scc           0.0%      0.0%     -0.1%     -0.2%     -0.0%
          sched           0.0%      0.0%     -0.0%     -0.0%     -0.0%
            scs           0.0%      0.0%     -1.0%     -2.6%     +0.0%
         simple           0.0%      0.0%     +0.0%     -0.0%     +0.0%
          solid           0.0%      0.0%     -0.0%     -0.0%      0.0%
        sorting           0.0%      0.0%     -0.6%     -1.6%      0.0%
  spectral-norm           0.0%      0.0%     +0.0%      0.0%     +0.0%
         sphere           0.0%      0.0%     -0.0%     -0.0%     -0.0%
         symalg           0.0%      0.0%     -0.0%     -0.0%     +0.0%
            tak           0.0%      0.0%     -0.0%     -0.0%      0.0%
      transform           0.0%      0.0%     -0.0%     -0.0%      0.0%
       treejoin           0.0%      0.0%     -0.0%     -0.0%      0.0%
      typecheck           0.0%      0.0%     -0.0%     -0.0%     +0.0%
        veritas          +0.0%      0.0%     -0.2%     -0.4%     +0.0%
           wang           0.0%      0.0%     -0.0%     -0.0%      0.0%
      wave4main           0.0%      0.0%     -0.0%     -0.0%     -0.0%
   wheel-sieve1           0.0%      0.0%     -0.0%     -0.0%     -0.0%
   wheel-sieve2           0.0%      0.0%     -0.0%     -0.0%     +0.0%
           x2n1           0.0%      0.0%     -0.0%     -0.0%     -0.0%
--------------------------------------------------------------------------------
            Min           0.0%      0.0%     -2.2%     -5.4%     -0.0%
            Max          +0.0%      0.0%     +0.0%     +0.0%     +0.1%
 Geometric Mean          -0.0%     -0.0%     -0.1%     -0.3%     +0.0%

Metric increases micro benchmarks tracked in #17686:

Metric Increase:
    T12150
    T12234
    T12425
    T13035
    T5837
    T6048
    T9233

Co-authored-by: Andreas Klebinger <klebinger.andreas at gmx.at>

- - - - -
3b22b14a by Shayne Fletcher at 2020-06-10T04:15:01-04:00
Give Language a Bounded instance

- - - - -
9454511b by Simon Peyton Jones at 2020-06-10T04:17:06-04:00
Optimisation in Unique.Supply

This patch switches on -fno-state-hack in GHC.Types.Unique.Supply.

It turned out that my fixes for #18078 (coercion floating) changed the
optimisation pathway for mkSplitUniqSupply in such a way that we had
an extra allocation inside the inner loop.  Adding -fno-state-hack
fixed that -- and indeed the loop in mkSplitUniqSupply is a classic
example of the way in which -fno-state-hack can be bad; see #18238.

Moreover, the new code is better than the old.  They allocate
the same, but the old code ends up with a partial application.
The net effect is that the test
    perf/should_run/UniqLoop
runs 20% faster!   From 2.5s down to 2.0s.  The allocation numbers
are the same -- but elapsed time falls. Good!

The bad thing about this is that it's terribly delicate.  But
at least it's a good example of such delicacy in action.

There is a long Note [Optimising the unique supply] which now
explains all this.

- - - - -
6d49d5be by Simon Peyton Jones at 2020-06-10T04:17:06-04:00
Implement cast worker/wrapper properly

The cast worker/wrapper transformation transforms
   x = e |> co
into
   y = e
   x = y |> co

This is done by the simplifier, but we were being
careless about transferring IdInfo from x to y,
and about what to do if x is a NOINLNE function.
This resulted in a series of bugs:
     #17673, #18093, #18078.

This patch fixes all that:

* Main change is in GHC.Core.Opt.Simplify, and
  the new prepareBinding function, which does this
  cast worker/wrapper transform.
  See Note [Cast worker/wrappers].

* There is quite a bit of refactoring around
  prepareRhs, makeTrivial etc.  It's nicer now.

* Some wrappers from strictness and cast w/w, notably those for
  a function with a NOINLINE, should inline very late. There
  wasn't really a mechanism for that, which was an existing bug
  really; so I invented a new finalPhase = Phase (-1).  It's used
  for all simplifier runs after the user-visible phase 2,1,0 have
  run.  (No new runs of the simplifier are introduced thereby.)

  See new Note [Compiler phases] in GHC.Types.Basic;
  the main changes are in GHC.Core.Opt.Driver

* Doing this made me trip over two places where the AnonArgFlag on a
  FunTy was being lost so we could end up with (Num a -> ty)
  rather than (Num a => ty)
    - In coercionLKind/coercionRKind
    - In contHoleType in the Simplifier

  I fixed the former by defining mkFunctionType and using it in
  coercionLKind/RKind.

  I could have done the same for the latter, but the information
  is almost to hand.  So I fixed the latter by
    - adding sc_hole_ty to ApplyToVal (like ApplyToTy),
    - adding as_hole_ty to ValArg (like TyArg)
    - adding sc_fun_ty to StrictArg
  Turned out I could then remove ai_type from ArgInfo.  This is
  just moving the deck chairs around, but it worked out nicely.

  See the new Note [AnonArgFlag] in GHC.Types.Var

* When looking at the 'arity decrease' thing (#18093) I discovered
  that stable unfoldings had a much lower arity than the actual
  optimised function.  That's what led to the arity-decrease
  message.  Simple solution: eta-expand.

  It's described in Note [Eta-expand stable unfoldings]
  in GHC.Core.Opt.Simplify

* I also discovered that unsafeCoerce wasn't being inlined if
  the context was boring.  So (\x. f (unsafeCoerce x)) would
  create a thunk -- yikes!  I fixed that by making inlineBoringOK
  a bit cleverer: see Note [Inline unsafeCoerce] in GHC.Core.Unfold.

  I also found that unsafeCoerceName was unused, so I removed it.

I made a test case for #18078, and a very similar one for #17673.

The net effect of all this on nofib is very modest, but positive:

--------------------------------------------------------------------------------
        Program           Size    Allocs   Runtime   Elapsed  TotalMem
--------------------------------------------------------------------------------
           anna          -0.4%     -0.1%     -3.1%     -3.1%      0.0%
 fannkuch-redux          -0.4%     -0.3%     -0.1%     -0.1%      0.0%
       maillist          -0.4%     -0.1%     -7.8%     -1.0%    -14.3%
      primetest          -0.4%    -15.6%     -7.1%     -6.6%      0.0%
--------------------------------------------------------------------------------
            Min          -0.9%    -15.6%    -13.3%    -14.2%    -14.3%
            Max          -0.3%      0.0%    +12.1%    +12.4%      0.0%
 Geometric Mean          -0.4%     -0.2%     -2.3%     -2.2%     -0.1%

All following metric decreases are compile-time allocation decreases
between -1% and -3%:

Metric Decrease:
  T5631
  T13701
  T14697
  T15164

- - - - -
32fd37f5 by Luke Lau at 2020-06-10T04:17:22-04:00
Fix lookupGlobalOccRn_maybe sometimes reporting an error

In some cases it was possible for lookupGlobalOccRn_maybe to return an
error, when it should be returning a Nothing. If it called
lookupExactOcc_either when there were no matching GlobalRdrElts in the
otherwise case, it would return an error message. This could be caused
when lookupThName_maybe in Template Haskell was looking in different
namespaces (thRdrNameGuesses), guessing different namespaces that the
name wasn't guaranteed to be found in.

However, by addressing this some more accurate errors were being lost in
the conversion to Maybes. So some of the lookup* functions have been
shuffled about so that errors should always be ignored in
lookup*_maybes, and propagated otherwise.

This fixes #18263

- - - - -
9b283e1b by Roland Senn at 2020-06-10T04:17:34-04:00
Initialize the allocation counter in GHCi to 0 (Fixes #16012)

According to the documentation for the function `getAllocationCounter` in
[System.Mem](http://hackage.haskell.org/package/base-4.14.0.0/docs/System-Mem.html)
initialize the allocationCounter also in GHCi to 0.

- - - - -
8d07c48c by Sylvain Henry at 2020-06-10T04:17:36-04:00
test: fix conc038

We had spurious failures of conc038 test on CI with stdout:

```
 newThread started
-mainThread
-Haskell: 2
 newThread back again
+mainThread
 1 sec later

 shutting down
+Haskell: 2
```

- - - - -
4c7e9689 by Sebastian Graf at 2020-06-11T10:37:38+02:00
Release Notes: Add news from the pattern-match checker [skip ci]

- - - - -
3445b965 by Sylvain Henry at 2020-06-13T02:13:01-04:00
Only test T16190 with the NCG

T16190 is meant to test a NCG feature. It has already caused spurious
failures in other MRs (e.g. !2165) when LLVM is used.

- - - - -
2517a51c by Sylvain Henry at 2020-06-13T02:13:01-04:00
DynFlags refactoring VIII (#17957)

* Remove several uses of `sdocWithDynFlags`, especially in GHC.Llvm.*

* Add LlvmOpts datatype to store Llvm backend options

* Remove Outputable instances (for LlvmVar, LlvmLit, LlvmStatic and
  Llvm.MetaExpr) which require LlvmOpts.

* Rename ppMetaExpr into ppMetaAnnotExpr (pprMetaExpr is now used in place of `ppr :: MetaExpr -> SDoc`)

- - - - -
7a02599a by Sylvain Henry at 2020-06-13T02:13:02-04:00
Remove unused code

- - - - -
72d08610 by Sylvain Henry at 2020-06-13T02:13:02-04:00
Refactor homeUnit

* rename thisPackage into homeUnit
* document and refactor several Backpack things

- - - - -
8dc71f55 by Sylvain Henry at 2020-06-13T02:13:02-04:00
Rename unsafeGetUnitInfo into unsafeLookupUnit

- - - - -
f6be6e43 by Sylvain Henry at 2020-06-13T02:13:02-04:00
Add allowVirtualUnits field in PackageState

Instead of always querying DynFlags to know whether we are allowed to
use virtual units (i.e. instantiated on-the-fly, cf Note [About units]
in GHC.Unit), we store it once for all in
`PackageState.allowVirtualUnits`.

This avoids using DynFlags too much (cf #17957) and is preliminary work
for #14335.

- - - - -
e7272d53 by Sylvain Henry at 2020-06-13T02:13:02-04:00
Enhance UnitId use

* use UnitId instead of String to identify wired-in units
* use UnitId instead of Unit in the backend (Unit are only use by
  Backpack to produce type-checked interfaces, not real code)
* rename lookup functions for consistency
* documentation

- - - - -
9c5572cd by Sylvain Henry at 2020-06-13T02:13:02-04:00
Remove LinkerUnitId type alias

- - - - -
d345edfe by Sylvain Henry at 2020-06-13T02:13:02-04:00
Refactor WiredMap

* Remove WiredInUnitId and WiredUnitId type aliases

- - - - -
3d171cd6 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Document and refactor `mkUnit` and `mkUnitInfoMap`

- - - - -
d2109b4f by Sylvain Henry at 2020-06-13T02:13:03-04:00
Remove PreloadUnitId type alias

- - - - -
f50c19b8 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Rename listUnitInfoMap into listUnitInfo

There is no Map involved

- - - - -
ed533ec2 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Rename Package into Unit

The terminology changed over time and now package databases contain
"units" (there can be several units compiled from a single Cabal
package: one per-component, one for each option set, one per
instantiation, etc.). We should try to be consistent internally and use
"units": that's what this renaming does. Maybe one day we'll fix the UI
too (e.g. replace -package-id with -unit-id, we already have
-this-unit-id and ghc-pkg has -unit-id...) but it's not done in this
patch.

* rename getPkgFrameworkOpts into getUnitFrameworkOpts
* rename UnitInfoMap into ClosureUnitInfoMap
* rename InstalledPackageIndex into UnitInfoMap
* rename UnusablePackages into UnusableUnits
* rename PackagePrecedenceIndex into UnitPrecedenceMap
* rename PackageDatabase into UnitDatabase
* rename pkgDatabase into unitDatabases
* rename pkgState into unitState
* rename initPackages into initUnits
* rename renamePackage into renameUnitInfo
* rename UnusablePackageReason into UnusableUnitReason
* rename getPackage* into getUnit*
* etc.

- - - - -
202728e5 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Make ClosureUnitInfoMap uses UnitInfoMap

- - - - -
55b4263e by Sylvain Henry at 2020-06-13T02:13:03-04:00
Remove ClosureUnitInfoMap

- - - - -
653d17bd by Sylvain Henry at 2020-06-13T02:13:03-04:00
Rename Package into Unit (2)

* rename PackageState into UnitState
* rename findWiredInPackages into findWiredInUnits
* rename lookupModuleInAll[Packages,Units]
* etc.

- - - - -
ae900605 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Move dump_mod_map into initUnits

- - - - -
598cc1dd by Sylvain Henry at 2020-06-13T02:13:03-04:00
Move wiring of homeUnitInstantiations outside of mkUnitState

- - - - -
437265eb by Sylvain Henry at 2020-06-13T02:13:03-04:00
Avoid timing module map dump in initUnits

- - - - -
9400aa93 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Remove preload parameter of mkUnitState

* Remove preload parameter (unused)
* Don't explicitly return preloaded units: redundant because already
  returned as "preloadUnits" field of UnitState

- - - - -
266bc3d9 by Sylvain Henry at 2020-06-13T02:13:03-04:00
DynFlags: refactor unwireUnit

- - - - -
9e715c1b by Sylvain Henry at 2020-06-13T02:13:03-04:00
Document getPreloadUnitsAnd

- - - - -
bd5810dc by Sylvain Henry at 2020-06-13T02:13:03-04:00
DynFlags: remove useless add_package parameter

- - - - -
36e1daf0 by Sylvain Henry at 2020-06-13T02:13:03-04:00
DynFlags: make listVisibleModuleNames take a UnitState

- - - - -
5226da37 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Refactor and document add_package

- - - - -
4b53aac1 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Refactor and document closeUnitDeps

- - - - -
42c054f6 by Sylvain Henry at 2020-06-13T02:13:03-04:00
DynFlags: findWiredInUnits

- - - - -
a444d01b by Sylvain Henry at 2020-06-13T02:13:03-04:00
DynFlags: reportCycles, reportUnusable

- - - - -
8408d521 by Sylvain Henry at 2020-06-13T02:13:03-04:00
DynFlags: merge_databases

- - - - -
fca2d25f by Sylvain Henry at 2020-06-13T02:13:03-04:00
DynFlags: add UnitConfig datatype

Avoid directly querying flags from DynFlags to build the UnitState.
Instead go via UnitConfig so that we could reuse this to make another
UnitState for plugins.

- - - - -
4274688a by Sylvain Henry at 2020-06-13T02:13:03-04:00
Move distrustAll into mkUnitState

- - - - -
28d804e1 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Create helper upd_wired_in_home_instantiations

- - - - -
ac964c83 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Put database cache in UnitConfig

- - - - -
bfd0a78c by Sylvain Henry at 2020-06-13T02:13:03-04:00
Don't return preload units when we set DyNFlags

Preload units can be retrieved in UnitState when needed (i.e. in GHCi)

- - - - -
1fbb4bf5 by Sylvain Henry at 2020-06-13T02:13:03-04:00
NCGConfig: remove useless ncgUnitId field

- - - - -
c10ff7e7 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Doc: fix some comments

- - - - -
456e17f0 by Sylvain Henry at 2020-06-13T02:13:03-04:00
Bump haddock submodule and allow metric decrease

Metric Decrease:
    T12150
    T12234
    T5837

Metric Increase:
    T16190

- - - - -
42953902 by Simon Peyton Jones at 2020-06-13T02:13:03-04:00
Trim the demand for recursive product types

Ticket #18304 showed that we need to be very careful
when exploring the demand (esp usage demand) on recursive
product types.

This patch solves the problem by trimming the demand on such types --
in effect, a form of "widening".

See the Note [Trimming a demand to a type] in DmdAnal, which explains
how I did this by piggy-backing on an existing mechansim for trimming
demands becuase of GADTs.  The significant payload of this patch is
very small indeed:

* Make GHC.Core.Opt.WorkWrap.Utils.typeShape use RecTcChecker to
  avoid looking through recursive types.

But on the way

* I found that ae_rec_tc was entirely inoperative and did nothing.
  So I removed it altogether from DmdAnal.

* I moved some code around in DmdAnal and Demand.
  (There are no actual changes in dmdFix.)

* I changed the API of DmsAnal.dmdAnalRhsLetDown to return
  a StrictSig rather than a decorated Id

* I removed the dead function peelTsFuns from Demand

Performance effects:

Nofib: 0.0% changes.  Not surprising, because they don't
       use recursive products

Perf tests

T12227:
  1% increase in compiler allocation, becuase $cto gets w/w'd.
  It did not w/w before because it takes a deeply nested
  argument, so the worker gets too many args, so we abandon w/w
  altogether (see GHC.Core.Opt.WorkWrap.Utils.isWorkerSmallEnough)

  With this patch we trim the demands.  That is not strictly
  necessary (since these Generic type constructors are like
  tuples -- they can't cause a loop) but the net result is that
  we now w/w $cto which is fine.

UniqLoop:
  16% decrease in /runtime/ allocation. The UniqSupply is a
  recursive product, so currently we abandon all strictness on
  'churn'.  With this patch 'churn' gets useful strictness, and
  we w/w it.  Hooray

Metric Decrease:
    UniqLoop

Metric Increase:
    T12227

- - - - -
87d504f4 by Viktor Dukhovni at 2020-06-13T02:13:05-04:00
Add introductory prose for Data.Traversable

- - - - -
9f09b608 by Oleg Grenrus at 2020-06-13T02:13:07-04:00
Fix #12073: Add MonadFix Q instance

- - - - -
220c2d34 by Ben Gamari at 2020-06-13T02:13:07-04:00
testsuite: Increase size of T12150

As noted in #18319, this test was previously very fragile. Increase its
size to make it more likely that its fails with its newly-increased
acceptance threshold.

Metric Increase:
    T12150

- - - - -
8bba1c26 by Ben Gamari at 2020-06-13T04:59:06-04:00
gitlab-ci: Always push perf notes

Previously we ci.sh would run with `set -e` implying that we wouldn't
push perf notes if the testsuite were to fail, even if it *only* failed
due to perf notes. This rendered the whole performance testing story
quite fragile as a single regressing commit would cause every successive
commit to fail since a new baseline would not be uploaded.

Fix this by ensuring that we always push performance notes.

- - - - -
7a773f16 by Ben Gamari at 2020-06-13T15:10:55-04:00
gitlab-ci: Eliminate redundant push of CI metrics

- - - - -
a31218f7 by Ryan Scott at 2020-06-13T15:58:37-04:00
Use HsForAllTelescope to avoid inferred, visible foralls

Currently, `HsForAllTy` permits the combination of `ForallVis` and
`Inferred`, but you can't actually typecheck code that uses it
(e.g., `forall {a} ->`). This patch refactors `HsForAllTy` to use a
new `HsForAllTelescope` data type that makes a type-level distinction
between visible and invisible `forall`s such that visible `forall`s
do not track `Specificity`. That part of the patch is actually quite
small; the rest is simply changing consumers of `HsType` to
accommodate this new type.

Fixes #18235. Bumps the `haddock` submodule.

- - - - -
c0e6dee9 by Tamar Christina at 2020-06-14T09:07:44-04:00
winio: Add Atomic Exchange PrimOp and implement Atomic Ptr exchanges.

The initial version was rewritten by Tamar Christina.
It was rewritten in large parts by Andreas Klebinger.

Co-authored-by: Andreas Klebinger <klebinger.andreas at gmx.at>

- - - - -
9a7462fb by Ben Gamari at 2020-06-14T15:35:23-04:00
codeGen: Don't discard live case binders in unsafeEqualityProof logic

Previously CoreToStg would unconditionally discard cases of the form:

    case unsafeEqualityProof of wild { _ -> rhs }

and rather replace the whole thing with `rhs`. However, in some cases
(see #18227) the case binder is still live, resulting in unbound
occurrences in `rhs`. Fix this by only discarding the case if the case
binder is dead.

Fixes #18227.

- - - - -
e4137c48 by Ben Gamari at 2020-06-14T15:35:23-04:00
testsuite: Add tests for #18227

T18227A is the original issue which gave rise to the ticket and depends
upon bytestring. T18227B is a minimized reproducer.

- - - - -
8bab9ff1 by Ben Gamari at 2020-06-14T15:35:59-04:00
hadrian: Fix rts include and library paths

Fixes two bugs:

 * (?) and (<>) associated in a surprising way
 * We neglected to include libdw paths in the rts configure flags

- - - - -
bd761185 by Ben Gamari at 2020-06-14T15:35:59-04:00
hadrian: Drop redundant GHC arguments

Cabal should already be passing this arguments to GHC.

- - - - -
01f7052c by Peter Trommler at 2020-06-14T15:36:38-04:00
FFI: Fix pass small ints in foreign call wrappers

The Haskell calling convention requires integer parameters smaller
than wordsize to be promoted to wordsize (where the upper bits are
don't care). To access such small integer parameter read a word from
the parameter array and then cast that word to the small integer
target type.

Fixes #15933

- - - - -
502647f7 by Krzysztof Gogolewski at 2020-06-14T15:37:14-04:00
Fix "ndecreasingIndentation" in manual (#18116)

- - - - -
9a9cc089 by Simon Jakobi at 2020-06-15T13:10:00-04:00
Use foldl' in unionManyUniqDSets

- - - - -
761dcb84 by Moritz Angermann at 2020-06-15T13:10:36-04:00
Load .lo as well.

Some archives contain so called linker objects, with the affectionate
.lo suffic.  For example the musl libc.a will come in that form.  We
still want to load those objects, hence we should not discard them and
look for .lo as well.  Ultimately we might want to fix this proerly by
looking at the file magic.

- - - - -
cf01477f by Vladislav Zavialov at 2020-06-15T13:11:20-04:00
User's Guide: KnownNat evidence is Natural

This bit of documentation got outdated after commit
1fcede43d2b30f33b7505e25eb6b1f321be0407f

- - - - -
d0dcbfe6 by Jan Hrček at 2020-06-16T20:36:38+02:00
Fix typos and formatting in user guide

- - - - -
56a9e95f by Jan Hrček at 2020-06-16T20:36:38+02:00
Resolve TODO

- - - - -
3e884d14 by Jan Hrček at 2020-06-16T20:36:38+02:00
Rename TcHoleErrors to GHC.Tc.Errors.Hole

- - - - -
d23fc678 by Stefan Schulze Frielinghaus at 2020-06-17T15:31:09-04:00
hadrian: Build with threaded runtime if available

See #16873.

- - - - -
0639dc10 by Sylvain Henry at 2020-06-17T15:31:53-04:00
T16190: only measure bytes_allocated

Just adding `{-# LANGUAGE BangPatterns #-}` makes the two other metrics
fluctuate by 13%.

- - - - -
4cab6897 by Adam Sandberg Ericsson at 2020-06-17T15:32:44-04:00
docs: fix formatting in users guide

- - - - -
eb8115a8 by Sylvain Henry at 2020-06-17T15:33:23-04:00
Move CLabel assertions into smart constructors (#17957)

It avoids using DynFlags in the Outputable instance of Clabel to check
assertions at pretty-printing time.

- - - - -
7faa4509 by Ben Gamari at 2020-06-17T15:43:31-04:00
base: Bump to 4.15.0.0

- - - - -
20616959 by Ben Gamari at 2020-06-17T15:43:31-04:00
configure: Use grep -q instead of --quiet

The latter is apparently not supported by busybox.

- - - - -
40fa237e by Krzysztof Gogolewski at 2020-06-17T16:21:58-04:00
Linear types (#15981)

This is the first step towards implementation of the linear types proposal
(https://github.com/ghc-proposals/ghc-proposals/pull/111).

It features

* A language extension -XLinearTypes
* Syntax for linear functions in the surface language
* Linearity checking in Core Lint, enabled with -dlinear-core-lint
* Core-to-core passes are mostly compatible with linearity
* Fields in a data type can be linear or unrestricted; linear fields
  have multiplicity-polymorphic constructors.
  If -XLinearTypes is disabled, the GADT syntax defaults to linear fields

The following items are not yet supported:

* a # m -> b syntax (only prefix FUN is supported for now)
* Full multiplicity inference (multiplicities are really only checked)
* Decent linearity error messages
* Linear let, where, and case expressions in the surface language
  (each of these currently introduce the unrestricted variant)
* Multiplicity-parametric fields
* Syntax for annotating lambda-bound or let-bound with a multiplicity
* Syntax for non-linear/multiple-field-multiplicity records
* Linear projections for records with a single linear field
* Linear pattern synonyms
* Multiplicity coercions (test LinearPolyType)

A high-level description can be found at
https://ghc.haskell.org/trac/ghc/wiki/LinearTypes/Implementation
Following the link above you will find a description of the changes made to Core.
This commit has been authored by

* Richard Eisenberg
* Krzysztof Gogolewski
* Matthew Pickering
* Arnaud Spiwack

With contributions from:

* Mark Barbone
* Alexander Vershilov

Updates haddock submodule.

- - - - -
6cb84c46 by Krzysztof Gogolewski at 2020-06-17T16:22:03-04:00
Various performance improvements

This implements several general performance improvements to GHC,
to offset the effect of the linear types change.

General optimisations:
- Add a `coreFullView` function which iterates `coreView` on the
  head. This avoids making function recursive solely because the
  iterate `coreView` themselves. As a consequence, this functions can
  be inlined, and trigger case-of-known constructor (_e.g._
  `kindRep_maybe`, `isLiftedRuntimeRep`, `isMultiplicityTy`,
  `getTyVar_maybe`, `splitAppTy_maybe`, `splitFunType_maybe`,
  `tyConAppTyCon_maybe`). The common pattern about all these functions
  is that they are almost always used as views, and immediately
  consumed by a case expression. This commit also mark them asx `INLINE`.
- In `subst_ty` add a special case for nullary `TyConApp`, which avoid
  allocations altogether.
- Use `mkTyConApp` in `subst_ty` for the general `TyConApp`. This
  required quite a bit of module shuffling.
  case. `myTyConApp` enforces crucial sharing, which was lost during
  substitution. See also !2952 .
- Make `subst_ty` stricter.
- In `eqType` (specifically, in `nonDetCmpType`), add a special case,
  tested first, for the very common case of nullary `TyConApp`.
  `nonDetCmpType` has been made `INLINE` otherwise it is actually a
  regression. This is similar to the optimisations in !2952.

Linear-type specific optimisations:
- Use `tyConAppTyCon_maybe` instead of the more complex `eqType` in
  the definition of the pattern synonyms `One` and `Many`.
- Break the `hs-boot` cycles between `Multiplicity.hs` and `Type.hs`:
  `Multiplicity` now import `Type` normally, rather than from the
  `hs-boot`. This way `tyConAppTyCon_maybe` can inline properly in the
  `One` and `Many` pattern synonyms.
- Make `updateIdTypeAndMult` strict in its type and multiplicity
- The `scaleIdBy` gets a specialised definition rather than being an
  alias to `scaleVarBy`
- `splitFunTy_maybe` is given the type `Type -> Maybe (Mult, Type,
  Type)` instead of `Type -> Maybe (Scaled Type, Type)`
- Remove the `MultMul` pattern synonym in favour of a view `isMultMul`
  because pattern synonyms appear not to inline well.
- in `eqType`, in a `FunTy`, compare multiplicities last: they are
  almost always both `Many`, so it helps failing faster.
- Cache `manyDataConTy` in `mkTyConApp`, to make sure that all the
  instances of `TyConApp ManyDataConTy []` are physically the same.

This commit has been authored by
* Richard Eisenberg
* Krzysztof Gogolewski
* Arnaud Spiwack

Metric Decrease:
    haddock.base
    T12227
    T12545
    T12990
    T1969
    T3064
    T5030
    T9872b

Metric Increase:
    haddock.base
    haddock.Cabal
    haddock.compiler
    T12150
    T12234
    T12425
    T12707
    T13035
    T13056
    T15164
    T16190
    T18304
    T1969
    T3064
    T3294
    T5631
    T5642
    T5837
    T6048
    T9020
    T9233
    T9675
    T9872a
    T9961
    WWRec

- - - - -
57db91d8 by Sylvain Henry at 2020-06-17T16:22:03-04:00
Remove integer-simple

integer-simple uses lists of words (`[Word]`) to represent big numbers
instead of ByteArray#:

   * it is less efficient than the newer ghc-bignum native backend

   * it isn't compatible with the big number representation that is now
     shared by all the ghc-bignum backends (based on the one that was
     used only in integer-gmp before).

As a consequence, we simply drop integer-simple

- - - - -
9f96bc12 by Sylvain Henry at 2020-06-17T16:22:03-04:00
ghc-bignum library

ghc-bignum is a newer package that aims to replace the legacy
integer-simple and integer-gmp packages.

* it supports several backends. In particular GMP is still supported and
  most of the code from integer-gmp has been merged in the "gmp"
  backend.

* the pure Haskell "native" backend is new and is much faster than the
  previous pure Haskell implementation provided by integer-simple

* new backends are easier to write because they only have to provide a
  few well defined functions. All the other code is common to all
  backends. In particular they all share the efficient small/big number
  distinction previously used only in integer-gmp.

* backends can all be tested against the "native" backend with a simple
  Cabal flag. Backends are only allowed to differ in performance, their
  results should be the same.

* Add `integer-gmp` compat package: provide some pattern synonyms and
  function aliases for those in `ghc-bignum`. It is intended to avoid
  breaking packages that depend on `integer-gmp` internals.

Update submodules: text, bytestring

Metric Decrease:
    Conversions
    ManyAlternatives
    ManyConstructors
    Naperian
    T10359
    T10547
    T10678
    T12150
    T12227
    T12234
    T12425
    T13035
    T13719
    T14936
    T1969
    T4801
    T4830
    T5237
    T5549
    T5837
    T8766
    T9020
    parsing001
    space_leak_001
    T16190
    haddock.base

On ARM and i386, T17499 regresses (+6% > 5%).
On x86_64 unregistered, T13701 sometimes regresses (+2.2% > 2%).

Metric Increase:
    T17499
    T13701

- - - - -
96aa5787 by Sylvain Henry at 2020-06-17T16:22:03-04:00
Update compiler

Thanks to ghc-bignum, the compiler can be simplified:

* Types and constructors of Integer and Natural can be wired-in. It
  means that we don't have to query them from interfaces. It also means
  that numeric literals don't have to carry their type with them.

* The same code is used whatever ghc-bignum backend is enabled. In
  particular, conversion of bignum literals into final Core expressions
  is now much more straightforward. Bignum closure inspection too.

* GHC itself doesn't depend on any integer-* package anymore

* The `integerLibrary` setting is gone.

- - - - -
0f67e344 by Sylvain Henry at 2020-06-17T16:22:03-04:00
Update `base` package

* GHC.Natural isn't implemented in `base` anymore. It is provided by
  ghc-bignum in GHC.Num.Natural. It means that we can safely use Natural
  primitives in `base` without fearing issues with built-in rewrite
  rules (cf #15286)

* `base` doesn't conditionally depend on an integer-* package anymore,
  it depends on ghc-bignum

* Some duplicated code in integer-* can now be factored in GHC.Float

* ghc-bignum tries to use a uniform naming convention so most of the
  other changes are renaming

- - - - -
aa9e7b71 by Sylvain Henry at 2020-06-17T16:22:03-04:00
Update `make` based build system

* replace integer-* package selection with ghc-bignum backend selection

- - - - -
f817d816 by Sylvain Henry at 2020-06-17T16:22:04-04:00
Update testsuite

* support detection of slow ghc-bignum backend (to replace the detection
  of integer-simple use). There are still some test cases that the
  native backend doesn't handle efficiently enough.

* remove tests for GMP only functions that have been removed from
  ghc-bignum

* fix test results showing dependent packages (e.g. integer-gmp) or
  showing suggested instances

* fix test using Integer/Natural API or showing internal names

- - - - -
dceecb09 by Sylvain Henry at 2020-06-17T16:22:04-04:00
Update Hadrian

* support ghc-bignum backend selection in flavours and command-line

* support ghc-bignum "--check" flag (compare results of selected backend
  against results of the native one) in flavours and command-line (e.g.
  pass --bignum=check-gmp" to check the "gmp" backend)

* remove the hack to workaround #15286

* build GMP only when the gmp backend is used

* remove hacks to workaround `text` package flags about integer-*. We
  fix `text` to use ghc-bignum unconditionally in another patch

- - - - -
fa4281d6 by Sylvain Henry at 2020-06-17T16:22:04-04:00
Bump bytestring and text submodules

- - - - -
1a3f6f34 by Adam Sandberg Ericsson at 2020-06-18T23:03:36-04:00
docs: mention -hiedir in docs for -outputdir

[skip ci]

- - - - -
729bcb02 by Sylvain Henry at 2020-06-18T23:04:17-04:00
Hadrian: fix build on Mac OS Catalina (#17798)

- - - - -
95e18292 by Andreas Klebinger at 2020-06-18T23:04:58-04:00
Relax allocation threshold for T12150.

This test performs little work, so the most minor allocation
changes often cause the test to fail.

Increasing the threshold to 2% should help with this.

- - - - -
8ce6c393 by Sebastian Graf at 2020-06-18T23:05:36-04:00
hadrian: Bump pinned cabal.project to an existent index-state

- - - - -
08c1cb0f by Ömer Sinan Ağacan at 2020-06-18T23:06:21-04:00
Fix uninitialized field read in Linker.c

Valgrind report of the bug when running the test `linker_unload`:

    ==29666== Conditional jump or move depends on uninitialised value(s)
    ==29666==    at 0x369C5B4: setOcInitialStatus (Linker.c:1305)
    ==29666==    by 0x369C6C5: mkOc (Linker.c:1347)
    ==29666==    by 0x36C027A: loadArchive_ (LoadArchive.c:522)
    ==29666==    by 0x36C0600: loadArchive (LoadArchive.c:626)
    ==29666==    by 0x2C144CD: ??? (in /home/omer/haskell/ghc_2/testsuite/tests/rts/linker/linker_unload.run/linker_unload)
    ==29666==
    ==29666== Conditional jump or move depends on uninitialised value(s)
    ==29666==    at 0x369C5B4: setOcInitialStatus (Linker.c:1305)
    ==29666==    by 0x369C6C5: mkOc (Linker.c:1347)
    ==29666==    by 0x369C9F6: preloadObjectFile (Linker.c:1507)
    ==29666==    by 0x369CA8D: loadObj_ (Linker.c:1536)
    ==29666==    by 0x369CB17: loadObj (Linker.c:1557)
    ==29666==    by 0x3866BC: main (linker_unload.c:33)

The problem is `mkOc` allocates a new `ObjectCode` and calls
`setOcInitialStatus` without initializing the `status` field.
`setOcInitialStatus` reads the field as first thing:

    static void setOcInitialStatus(ObjectCode* oc) {
        if (oc->status == OBJECT_DONT_RESOLVE)
          return;

        if (oc->archiveMemberName == NULL) {
            oc->status = OBJECT_NEEDED;
        } else {
            oc->status = OBJECT_LOADED;
        }
    }

`setOcInitialStatus` is unsed in two places for two different purposes:
in `mkOc` where we don't have the `status` field initialized yet (`mkOc`
is supposed to initialize it), and `loadOc` where we do have `status`
field initialized and we want to update it. Instead of splitting the
function into two functions which are both called just once I inline the
functions in the use sites and remove it.

Fixes #18342

- - - - -
da18ff99 by Tamar Christina at 2020-06-18T23:07:03-04:00
fix windows bootstrap due to linker changes

- - - - -
2af0ec90 by Sylvain Henry at 2020-06-18T23:07:47-04:00
DynFlags: store default depth in SDocContext (#17957)

It avoids having to use DynFlags to reach for pprUserLength.

- - - - -
d4a0be75 by Sylvain Henry at 2020-06-18T23:08:35-04:00
Move tablesNextToCode field into Platform

tablesNextToCode is a platform setting and doesn't belong into DynFlags
(#17957). Doing this is also a prerequisite to fix #14335 where we deal
with two platforms (target and host) that may have different platform
settings.

- - - - -
809caedf by John Ericson at 2020-06-23T22:47:37-04:00
Switch from HscSource to IsBootInterface for module lookup in GhcMake

We look up modules by their name, and not their contents. There is no
way to separately reference a signature vs regular module; you get what
you get. Only boot files can be referenced indepenently with `import {-#
SOURCE #-}`.

- - - - -
7750bd45 by Sylvain Henry at 2020-06-23T22:48:18-04:00
Cmm: introduce SAVE_REGS/RESTORE_REGS

We don't want to save both Fn and Dn register sets on x86-64 as they are
aliased to the same arch register (XMMn).

Moreover, when SAVE_STGREGS was used in conjunction with `jump foo [*]`
which makes a set of Cmm registers alive so that they cover all arch
registers used to pass parameter, we could have Fn, Dn and XMMn alive at
the same time. It made the LLVM code generator choke (see #17920).

Now `SAVE_REGS/RESTORE_REGS` and `jump foo [*]` use the same set of
registers.

- - - - -
2636794d by Sylvain Henry at 2020-06-23T22:48:18-04:00
CmmToC: don't add extern decl to parsed Cmm data

Previously, if a .cmm file *not in the RTS* contained something like:

```cmm
section "rodata" { msg : bits8[] "Test\n"; }
```

It would get compiled by CmmToC into:

```c
ERW_(msg);
const char msg[] = "Test\012";
```

and fail with:

```
/tmp/ghc32129_0/ghc_4.hc:5:12: error:
     error: conflicting types for \u2018msg\u2019
     const char msg[] = "Test\012";
                ^~~

In file included from /tmp/ghc32129_0/ghc_4.hc:3:0: error:

/tmp/ghc32129_0/ghc_4.hc:4:6: error:
     note: previous declaration of \u2018msg\u2019 was here
     ERW_(msg);
          ^

/builds/hsyl20/ghc/_build/install/lib/ghc-8.11.0.20200605/lib/../lib/x86_64-linux-ghc-8.11.0.20200605/rts-1.0/include/Stg.h:253:46: error:
     note: in definition of macro \u2018ERW_\u2019
     #define ERW_(X)   extern       StgWordArray (X)
                                                  ^
```

See the rationale for this on https://gitlab.haskell.org/ghc/ghc/-/wikis/commentary/compiler/backends/ppr-c#prototypes

Now we don't generate these extern declarations (ERW_, etc.) for
top-level data. It shouldn't change anything for the RTS (the only place
we use .cmm files) as it is already special cased in
`GHC.Cmm.CLabel.needsCDecl`. And hand-written Cmm can use explicit
extern declarations when needed.

Note that it allows `cgrun069` test to pass with CmmToC (cf #15467).

- - - - -
5f6a0665 by Sylvain Henry at 2020-06-23T22:48:18-04:00
LLVM: refactor and comment register padding code (#17920)

- - - - -
cad62ef1 by Sylvain Henry at 2020-06-23T22:48:18-04:00
Add tests for #17920

Metric Decrease:
    T12150
    T12234

- - - - -
a2a9006b by Xavier Denis at 2020-06-23T22:48:56-04:00
Fix issue #18262 by zonking constraints after solving

Zonk residual constraints in checkForExistence to reveal user type
errors.

Previously when `:instances` was used with instances that have TypeError
constraints the result would look something like:

instance [safe] s0 => Err 'A -- Defined at ../Bug2.hs:8:10

whereas after zonking, `:instances` now sees the `TypeError` and
properly eliminates the constraint from the results.

- - - - -
181516bc by Simon Peyton Jones at 2020-06-23T22:49:33-04:00
Fix a buglet in Simplify.simplCast

This bug, revealed by #18347, is just a missing update to
sc_hole_ty in simplCast.  I'd missed a code path when I
made the recentchanges in

    commit 6d49d5be904c0c01788fa7aae1b112d5b4dfaf1c
    Author: Simon Peyton Jones <simonpj at microsoft.com>
    Date:   Thu May 21 12:53:35 2020 +0100

    Implement cast worker/wrapper properly

The fix is very easy.

Two other minor changes

* Tidy up in SimpleOpt.simple_opt_expr. In fact I think this is an
  outright bug, introduced in the fix to #18112: we were simplifying
  the same coercion twice *with the same substitution*, which is just
  wrong.  It'd be a hard bug to trigger, so I just fixed it; less code
  too.

* Better debug printing of ApplyToVal

- - - - -
625a7f54 by Simon Peyton Jones at 2020-06-23T22:50:11-04:00
Two small tweaks to Coercion.simplifyArgsWorker

These tweaks affect the inner loop of simplifyArgsWorker, which
in turn is called from the flattener in Flatten.hs.  This is
a key perf bottleneck to T9872{a,b,c,d}.

These two small changes have a modest but useful benefit.
No change in functionality whatsoever.

Relates to #18354

- - - - -
b5768cce by Sylvain Henry at 2020-06-23T22:50:49-04:00
Don't use timesInt2# with GHC < 8.11 (fix #18358)

- - - - -
7ad4085c by Sylvain Henry at 2020-06-23T22:51:27-04:00
Fix invalid printf format

- - - - -
a1f34d37 by Krzysztof Gogolewski at 2020-06-23T22:52:09-04:00
Add missing entry to freeNamesItem (#18369)

- - - - -
03a708ba by Andreas Klebinger at 2020-06-25T03:54:37-04:00
Enable large address space optimization on windows.

Starting with Win 8.1/Server 2012 windows no longer preallocates
page tables for reserverd memory eagerly, which prevented us from
using this approach in the past.

We also try to allocate the heap high in the memory space.
Hopefully this makes it easier to allocate things in the low
4GB of memory that need to be there. Like jump islands for the
linker.

- - - - -
7e6d3d09 by Roland Senn at 2020-06-25T03:54:38-04:00
In `:break ident` allow out of scope and nested identifiers (Fix #3000)

This patch fixes the bug and implements the feature request of #3000.

1. If `Module` is a real module name and `identifier` a name of a
top-level function in `Module` then `:break Module.identifer` works
also for an `identifier` that is out of scope.

2. Extend the syntax for `:break identifier` to:

    :break [ModQual.]topLevelIdent[.nestedIdent]...[.nestedIdent]

`ModQual` is optional and is either the effective name of a module or
the local alias of a qualified import statement.

`topLevelIdent` is the name of a top level function in the module
referenced by `ModQual`.

`nestedIdent` is optional and the name of a function nested in a let or
where clause inside the previously mentioned function `nestedIdent` or
`topLevelIdent`.

If `ModQual` is a module name, then `topLevelIdent` can be any top level
identifier in this module. If `ModQual` is missing or a local alias of a
qualified import, then `topLevelIdent` must be in scope.

Breakpoints can be set on arbitrarily deeply nested functions, but the
whole chain of nested function names must be specified.

3. To support the new functionality rewrite the code to tab complete `:break`.

- - - - -
30e42652 by Ben Gamari at 2020-06-25T03:54:39-04:00
make: Respect XELATEX variable

Previously we simply ignored the XELATEX variable when building
PDF documentation.

- - - - -
4acc2934 by Ben Gamari at 2020-06-25T03:54:39-04:00
hadrian/make: Detect makeindex

Previously we would simply assume that makeindex was available.
Now we correctly detect it in `configure` and respect this conclusion in
hadrian and make.

- - - - -
0d61f866 by Simon Peyton Jones at 2020-06-25T03:54:40-04:00
Expunge GhcTcId

GHC.Hs.Extension had

  type GhcPs   = GhcPass 'Parsed
  type GhcRn   = GhcPass 'Renamed
  type GhcTc   = GhcPass 'Typechecked
  type GhcTcId = GhcTc

The last of these, GhcTcId, is a vestige of the past.

This patch expunges it from GHC.

- - - - -
8ddbed4a by Adam Wespiser at 2020-06-25T03:54:40-04:00
add examples to Data.Traversable

- - - - -
284001d0 by Oleg Grenrus at 2020-06-25T03:54:42-04:00
Export readBinIface_

- - - - -
90f43872 by Zubin Duggal at 2020-06-25T03:54:43-04:00
Export everything from HsToCore.

This lets us reuse these functions in haddock, avoiding synchronization bugs.

Also fixed some divergences with haddock in that file

Updates haddock submodule

- - - - -
c7dd6da7 by Takenobu Tani at 2020-06-25T03:54:44-04:00
Clean up haddock hyperlinks of GHC.* (part1)

This updates haddock comments only.

This patch focuses to update for hyperlinks in GHC API's haddock comments,
because broken links especially discourage newcomers.

This includes the following hierarchies:
  - GHC.Hs.*
  - GHC.Core.*
  - GHC.Stg.*
  - GHC.Cmm.*
  - GHC.Types.*
  - GHC.Data.*
  - GHC.Builtin.*
  - GHC.Parser.*
  - GHC.Driver.*
  - GHC top

- - - - -
1eb997a8 by Takenobu Tani at 2020-06-25T03:54:44-04:00
Clean up haddock hyperlinks of GHC.* (part2)

This updates haddock comments only.

This patch focuses to update for hyperlinks in GHC API's haddock comments,
because broken links especially discourage newcomers.

This includes the following hierarchies:

  - GHC.Iface.*
  - GHC.Llvm.*

  - GHC.Rename.*
  - GHC.Tc.*

  - GHC.HsToCore.*
  - GHC.StgToCmm.*
  - GHC.CmmToAsm.*

  - GHC.Runtime.*

  - GHC.Unit.*
  - GHC.Utils.*
  - GHC.SysTools.*

- - - - -
67a86b4d by Oleg Grenrus at 2020-06-25T03:54:46-04:00
Add MonadZip and MonadFix instances for Complex

These instances are taken from
https://hackage.haskell.org/package/linear-1.21/docs/Linear-Instances.html

They are the unique possible, so let they be in `base`.

- - - - -
c50ef26e by Artem Pelenitsyn at 2020-06-25T03:54:47-04:00
test suite: add reproducer for #17516

- - - - -
fe281b27 by Roland Senn at 2020-06-25T03:54:48-04:00
Enable maxBound checks for OverloadedLists (Fixes #18172)

Consider the Literal `[256] :: [Data.Word.Word8]`

When the `OverloadedLists` extension is not active, then the `ol_ext` field
in the `OverLitTc` record that is passed to the function `getIntegralLit`
contains the type `Word8`. This is a simple type, and we can use its
type constructor immediately for the `warnAboutOverflowedLiterals` function.

When the `OverloadedLists` extension is active, then the `ol_ext` field
contains the type family `Item [Word8]`. The function `nomaliseType` is used
to convert it to the needed type `Word8`.

- - - - -
a788d4d1 by Ben Gamari at 2020-06-25T03:54:52-04:00
rts/Hash: Simplify freeing of HashListChunks

While looking at #18348 I noticed that the treatment of HashLists are a
bit more complex than necessary (which lead to some initial confusion on
my part). Specifically, we allocate HashLists in chunks. Each chunk
allocation makes two allocations: one for the chunk itself and one for a
HashListChunk to link together the chunks for the purposes of freeing.

Simplify this (and hopefully make the relationship between these
clearer) but allocating the HashLists and HashListChunk in a single
malloc. This will both make the implementation easier to follow and
reduce C heap fragmentation.

Note that even after this patch we fail to bound the size of the free
HashList pool. However, this is a separate bug.

- - - - -
d3c2d59b by Sylvain Henry at 2020-06-25T03:54:55-04:00
RTS: avoid overflow on 32-bit arch (#18375)

We're now correctly computing allocated bytes on 32-bit arch, so we get
huge increases.

Metric Increase:
    haddock.Cabal
    haddock.base
    haddock.compiler
    space_leak_001

- - - - -
a3d69dc6 by Sebastian Graf at 2020-06-25T23:06:18-04:00
GHC.Core.Unify: Make UM actions one-shot by default

This MR makes the UM monad in GHC.Core.Unify into a one-shot
monad.  See the long Note [The one-shot state monad trick].

See also #18202 and !3309, which applies this to all Reader/State-like
monads in GHC for compile-time perf improvements. The pattern used
here enables something similar to the state-hack, but is applicable to
user-defined monads, not just `IO`.

Metric Decrease 'runtime/bytes allocated' (test_env='i386-linux-deb9'):
    haddock.Cabal

- - - - -
9ee58f8d by Matthias Pall Gissurarson at 2020-06-26T17:12:45+00:00
Implement the proposed -XQualifiedDo extension

Co-authored-by: Facundo Domínguez <facundo.dominguez at tweag.io>

QualifiedDo is implemented using the same placeholders for operation names in
the AST that were devised for RebindableSyntax. Whenever the renamer checks
which names to use for do syntax, it first checks if the do block is qualified
(e.g. M.do { stmts }), in which case it searches for qualified names in
the module M.

This allows users to write

    {-# LANGUAGE QualifiedDo #-}
    import qualified SomeModule as M

    f x = M.do           -- desugars to:
      y <- M.return x    -- M.return x M.>>= \y ->
      M.return y         -- M.return y M.>>
      M.return y         -- M.return y

See Note [QualifiedDo] and the users' guide for more details.

Issue #18214

Proposal:
https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0216-qualified-do.rst

Since we change the constructors `ITdo` and `ITmdo` to carry the new module
name, we need to bump the haddock submodule to account or the new shape of
these constructors.

- - - - -
ce987865 by Ryan Scott at 2020-06-27T11:55:21-04:00
Revamp the treatment of auxiliary bindings for derived instances

This started as a simple fix for #18321 that organically grew into a
much more sweeping refactor of how auxiliary bindings for derived
instances are handled. I have rewritten `Note [Auxiliary binders]`
in `GHC.Tc.Deriv.Generate` to explain all of the moving parts, but
the highlights are:

* Previously, the OccName of each auxiliary binding would be given
  a suffix containing a hash of its package name, module name, and
  parent data type to avoid name clashes. This was needlessly
  complicated, so we take the more direct approach of generating
  `Exact` `RdrName`s for each auxiliary binding with the same
  `OccName`, but using an underlying `System` `Name` with a fresh
  `Unique` for each binding. Unlike hashes, allocating new `Unique`s
  does not require any cleverness and avoid name clashes all the
  same...
* ...speaking of which, in order to convince the renamer that multiple
  auxiliary bindings with the same `OccName` (but different
  `Unique`s) are kosher, we now use `rnLocalValBindsLHS` instead of
  `rnTopBindsLHS` to rename auxiliary bindings. Again, see
  `Note [Auxiliary binders]` for the full story.
* I have removed the `DerivHsBind` constructor for
  `DerivStuff`—which was only used for `Data.Data`-related
  auxiliary bindings—and refactored `gen_Data_binds` to use
  `DerivAuxBind` instead. This brings the treatment of
  `Data.Data`-related auxiliary bindings in line with every other
  form of auxiliary binding.

Fixes #18321.

- - - - -
a403eb91 by Sylvain Henry at 2020-06-27T11:55:59-04:00
ghc-bignum: fix division by zero (#18359)

- - - - -
1b3d13b6 by Sylvain Henry at 2020-06-27T11:55:59-04:00
Fix ghc-bignum exceptions

We must ensure that exceptions are not simplified. Previously we used:

   case raiseDivZero of
      _ -> 0## -- dummyValue

But it was wrong because the evaluation of `raiseDivZero` was removed and
the dummy value was directly returned. See new Note [ghc-bignum exceptions].

I've also removed the exception triggering primops which were fragile.
We don't need them to be primops, we can have them exported by ghc-prim.

I've also added a test for #18359 which triggered this patch.

- - - - -
a74ec37c by Simon Peyton Jones at 2020-06-27T11:56:34-04:00
Better loop detection in findTypeShape

Andreas pointed out, in !3466, that my fix for #18304 was not
quite right.  This patch fixes it properly, by having just one
RecTcChecker rather than (implicitly) two nested ones, in
findTypeShape.

- - - - -
a04020b8 by Sylvain Henry at 2020-06-27T11:57:11-04:00
DynFlags: don't store buildTag

`DynFlags.buildTag` was a field created from the set of Ways in
`DynFlags.ways`. It had to be kept in sync with `DynFlags.ways` which
was fragile. We want to avoid global state like this (#17957).

Moreover in #14335 we also want to support loading units with different
ways: target units would still use `DynFlags.ways` but plugins would use
`GHC.Driver.Ways.hostFullWays`. To avoid having to deal both with build
tag and with ways, we recompute the buildTag on-the-fly (should be
pretty cheap) and we remove `DynFlags.buildTag` field.

- - - - -
0e83efa2 by Krzysztof Gogolewski at 2020-06-27T11:57:49-04:00
Don't generalize when typechecking a tuple section

The code is simpler and cleaner.

- - - - -
d8ba9e6f by Peter Trommler at 2020-06-28T09:19:11-04:00
RTS: Refactor Haskell-C glue for PPC 64-bit

Make sure the stack is 16 byte aligned even when reserved stack
bytes are not a multiple of 16 bytes.

Avoid saving r2 (TOC). On ELF v1 the function descriptor of StgReturn
has the same TOC as StgRun, on ELF v2 the TOC is recomputed in the
function prologue.

Use the ABI provided functions to save clobbered GPRs and FPRs.

Improve comments. Describe what the stack looks like and how it relates
to the respective ABIs.

- - - - -
42f797b0 by Ryan Scott at 2020-06-28T09:19:46-04:00
Use NHsCoreTy to embed types into GND-generated code

`GeneralizedNewtypeDeriving` is in the unique situation where it must
produce an `LHsType GhcPs` from a Core `Type`. Historically, this was
done with the `typeToLHsType` function, which walked over the entire
`Type` and attempted to construct an `LHsType` with the same overall
structure. `typeToLHsType` is quite complicated, however, and has
been the subject of numerous bugs over the years (e.g., #14579).

Luckily, there is an easier way to accomplish the same thing: the
`XHsType` constructor of `HsType`. `XHsType` bundles an `NHsCoreTy`,
which allows embedding a Core `Type` directly into an `HsType`,
avoiding the need to laboriously convert from one to another (as
`typeToLHsType` did). Moreover, renaming and typechecking an
`XHsType` is simple, since one doesn't need to do anything to a
Core `Type`...

...well, almost. For the reasons described in
`Note [Typechecking NHsCoreTys]` in `GHC.Tc.Gen.HsType`, we must
apply a substitution that we build from the local `tcl_env` type
environment. But that's a relatively modest price to pay.

Now that `GeneralizedNewtypeDeriving` uses `NHsCoreTy`, the
`typeToLHsType` function no longer has any uses in GHC, so this patch
rips it out. Some additional tweaks to `hsTypeNeedsParens` were
necessary to make the new `-ddump-deriv` output correctly
parenthesized, but other than that, this patch is quite
straightforward.

This is a mostly internal refactoring, although it is likely that
`GeneralizedNewtypeDeriving`-generated code will now need fewer
language extensions in certain situations than it did before.

- - - - -
68530b1c by Jan Hrček at 2020-06-28T09:20:22-04:00
Fix duplicated words and typos in comments and user guide

- - - - -
15b79bef by Ryan Scott at 2020-06-28T09:20:57-04:00
Add integer-gmp's ghc.mk and GNUmakefile to .gitignore

- - - - -
bfa5698b by Simon Peyton Jones at 2020-06-28T09:21:32-04:00
Fix a typo in Lint

This simple error in GHC.Core.Litn.lintJoinLams meant that
Lint reported bogus errors.

Fixes #18399

- - - - -
71006532 by Ryan Scott at 2020-06-30T07:10:42-04:00
Reject nested foralls/contexts in instance types more consistently

GHC is very wishy-washy about rejecting instance declarations with
nested `forall`s or contexts that are surrounded by outermost
parentheses. This can even lead to some strange interactions with
`ScopedTypeVariables`, as demonstrated in #18240. This patch makes
GHC more consistently reject instance types with nested
`forall`s/contexts so as to prevent these strange interactions.

On the implementation side, this patch tweaks `splitLHsInstDeclTy`
and `getLHsInstDeclHead` to not look through parentheses, which can
be semantically significant. I've added a
`Note [No nested foralls or contexts in instance types]` in
`GHC.Hs.Type` to explain why. This also introduces a
`no_nested_foralls_contexts_err` function in `GHC.Rename.HsType` to
catch nested `forall`s/contexts in instance types. This function is
now used in `rnClsInstDecl` (for ordinary instance declarations) and
`rnSrcDerivDecl` (for standalone `deriving` declarations), the latter
of which fixes #18271.

On the documentation side, this adds a new
"Formal syntax for instance declaration types" section to the GHC
User's Guide that presents a BNF-style grammar for what is and isn't
allowed in instance types.

Fixes #18240. Fixes #18271.

- - - - -
bccf3351 by Sylvain Henry at 2020-06-30T07:10:46-04:00
Add ghc-bignum to 8.12 release notes

- - - - -
81704a6f by David Eichmann at 2020-06-30T07:10:48-04:00
Update ssh keys in CI performance metrics upload script

- - - - -
85310fb8 by Joshua Price at 2020-06-30T07:10:49-04:00
Add missing Ix instances for tuples of size 6 through 15 (#16643)

- - - - -
cbb6b62f by Vladislav Zavialov at 2020-07-01T15:41:38-04:00
Implement -XLexicalNegation (GHC Proposal #229)

This patch introduces a new extension, -XLexicalNegation, which detects
whether the minus sign stands for negation or subtraction using the
whitespace-based rules described in GHC Proposal #229.

Updates haddock submodule.

- - - - -
fb5a0d01 by Martin Handley at 2020-07-01T15:42:14-04:00
#17169: Clarify Fixed's Enum instance.

- - - - -
b316804d by Simon Peyton Jones at 2020-07-01T15:42:49-04:00
Improve debug tracing for substitution

This patch improves debug tracing a bit (#18395)

* Remove the ancient SDoc argument to substitution, replacing it
  with a HasDebugCallStack constraint. The latter does the same
  job (indicate the call site) but much better.

* Add HasDebugCallStack to simpleOptExpr, exprIsConApp_maybe
  I needed this to help nail the lookupIdSubst panic in
  #18326, #17784

- - - - -
5c9fabb8 by Hécate at 2020-07-01T15:43:25-04:00
Add most common return values for `os` and `arch`

- - - - -
76d8cc74 by Ryan Scott at 2020-07-01T15:44:01-04:00
Desugar quoted uses of DerivingVia and expression type signatures properly

The way that `GHC.HsToCore.Quote` desugared quoted `via` types (e.g.,
`deriving via forall a. [a] instance Eq a => Eq (List a)`) and
explicit type annotations in signatures (e.g.,
`f = id @a :: forall a. a -> a`) was completely wrong, as it did not
implement the scoping guidelines laid out in
`Note [Scoped type variables in bindings]`. This is easily fixed.

While I was in town, I did some minor cleanup of related Notes:

* `Note [Scoped type variables in bindings]` and
  `Note [Scoped type variables in class and instance declarations]`
  say very nearly the same thing. I decided to just consolidate the
  two Notes into `Note [Scoped type variables in quotes]`.
* `Note [Don't quantify implicit type variables in quotes]` is
  somewhat outdated, as it predates GHC 8.10, where the
  `forall`-or-nothing rule requires kind variables to be explicitly
  quantified in the presence of an explicit `forall`. As a result,
  the running example in that Note doesn't even compile. I have
  changed the example to something simpler that illustrates the
  same point that the original Note was making.

Fixes #18388.

- - - - -
44d6a335 by Andreas Klebinger at 2020-07-02T02:54:54-04:00
T16012: Be verbose on failure.

- - - - -
f9853330 by Ryan Scott at 2020-07-02T02:55:29-04:00
Bump ghc-prim version to 0.7.0

Fixes #18279. Bumps the `text` submodule.

- - - - -
23e4e047 by Sylvain Henry at 2020-07-02T10:46:31-04:00
Hadrian: fix PowerPC64le support (#17601)

[ci skip]

- - - - -
3cdd8d69 by Sylvain Henry at 2020-07-02T10:47:08-04:00
NCG: correctly handle addresses with huge offsets (#15570)

Before this patch we could generate addresses of this form:

   movzbl cP0_str+-9223372036854775808,%eax

The linker can't handle them because the offset is too large:

   ld.lld: error: Main.o:(.text+0xB3): relocation R_X86_64_32S out of range: -9223372036852653050 is not in [-2147483648, 2147483647]

With this patch we detect those cases and generate:

   movq $-9223372036854775808,%rax
   addq $cP0_str,%rax
   movzbl (%rax),%eax

I've also refactored `getAmode` a little bit to make it easier to
understand and to trace.

- - - - -
4d90b3ff by Gabor Greif at 2020-07-02T20:07:59-04:00
No need for CURSES_INCLUDE_DIRS

This is a leftover from ef63ff27251a20ff11e58c9303677fa31e609a88
- - - - -
f08d6316 by Sylvain Henry at 2020-07-02T20:08:36-04:00
Replace Opt_SccProfilingOn flag with sccProfilingEnabled helper function

SCC profiling was enabled in a convoluted way: if WayProf was enabled,
Opt_SccProfilingOn general flag was set (in
`GHC.Driver.Ways.wayGeneralFlags`), and then this flag was queried in
various places.

There is no need to go via general flags, so this patch defines a
`sccProfilingEnabled :: DynFlags -> Bool` helper function that just
checks whether WayProf is enabled.

- - - - -
8cc7274b by Ben Gamari at 2020-07-03T02:49:27-04:00
rts/ProfHeap: Only allocate the Censuses that we need

When not LDV profiling there is no reason to allocate 32 Censuses; one
will do. This is a very small memory footprint optimisation, but it
comes for free.

- - - - -
b835112c by Ben Gamari at 2020-07-03T02:49:27-04:00
rts/ProfHeap: Free old allocations when reinitialising Censuses

Previously when not LDV profiling we would repeatedly reinitialise
`censuses[0]` with `initEra`. This failed to free the `Arena` and
`HashTable` from the old census, resulting in a memory leak.

Fixes #18348.

- - - - -
34be6523 by Valery Tolstov at 2020-07-03T02:50:03-04:00
Mention flags that are not enabled by -Wall (#18372)

* Mention missing flags that are not actually enabled by -Wall (docs/users_guide/using-warnings.rst)
* Additionally remove -Wmissing-monadfail-instances from the list of flags enabled by -Wcompat, as it is not the case since 8.8

- - - - -
edc8d22b by Sylvain Henry at 2020-07-03T02:50:40-04:00
LLVM: support R9 and R10 registers

d535ef006d85dbdb7cda2b09c5bc35cb80108909 allowed the use of up to 10
vanilla registers but didn't update LLVM backend to support them. This
patch fixes it.

- - - - -
4bf18646 by Simon Peyton Jones at 2020-07-03T08:37:42+01:00
Improve handling of data type return kinds

Following a long conversation with Richard, this patch tidies up the
handling of return kinds for data/newtype declarations (vanilla,
family, and instance).

I have substantially edited the Notes in TyCl, so they would
bear careful reading.

Fixes #18300, #18357

In GHC.Tc.Instance.Family.newFamInst we were checking some Lint-like
properties with ASSSERT.  Instead Richard and I have added
a proper linter for axioms, and called it from lintGblEnv, which in
turn is called in tcRnModuleTcRnM

New tests (T18300, T18357) cause an ASSERT failure in HEAD.

- - - - -
41d26492 by Sylvain Henry at 2020-07-03T17:33:59-04:00
DynFlags: avoid the use of sdocWithDynFlags in GHC.Core.Rules (#17957)

- - - - -
7aa6ef11 by Hécate at 2020-07-03T17:34:36-04:00
Add the __GHC_FULL_VERSION__ CPP macro to expose the full GHC version

- - - - -
e61d5395 by Chaitanya Koparkar at 2020-07-07T13:55:59-04:00
ghc-prim: Turn some comments into haddocks

[ci skip]

- - - - -
37743f91 by John Ericson at 2020-07-07T13:56:00-04:00
Support `timesInt2#` in LLVM backend

- - - - -
46397e53 by John Ericson at 2020-07-07T13:56:00-04:00
`genericIntMul2Op`: Call `genericWordMul2Op` directly

This unblocks a refactor, and removes partiality. It might be a PowerPC
regression but that should be fixable.

- - - - -
8a1c0584 by John Ericson at 2020-07-07T13:56:00-04:00
Simplify `PrimopCmmEmit`

Follow @simonpj's suggestion of pushing the "into regs" logic into
`emitPrimOp`. With the previous commit getting rid of the recursion in
`genericIntMul2Op`, this is now an easy refactor.

- - - - -
6607f203 by John Ericson at 2020-07-07T13:56:00-04:00
`opAllDone` -> `opIntoRegs`

The old name was and terrible and became worse after the previous
commit's refactor moved non-trivial funcationlity into its body.

- - - - -
fdcc53ba by Sylvain Henry at 2020-07-07T13:56:00-04:00
Optimise genericIntMul2Op

We shouldn't directly call 'genericWordMul2Op' in genericIntMul2Op
because a target may provide a faster primop for 'WordMul2Op': we'd
better use it!

- - - - -
686e7225 by Moritz Angermann at 2020-07-07T13:56:01-04:00
[linker/rtsSymbols] More linker symbols

Mostly symbols needed for aarch64/armv7l
and in combination with musl, where we have
to rely on loading *all* objects/archives

- __stack_chk_* only when not DYNAMIC

- - - - -
3f60b94d by Moritz Angermann at 2020-07-07T13:56:01-04:00
better if guards.

- - - - -
7abffced by Moritz Angermann at 2020-07-07T13:56:01-04:00
Fix (1)

- - - - -
cdfeb3f2 by Moritz Angermann at 2020-07-07T13:56:01-04:00
AArch32 symbols only on aarch32.

- - - - -
f496c955 by Adam Sandberg Ericsson at 2020-07-07T13:56:02-04:00
add -flink-rts flag to link the rts when linking a shared or static library #18072

By default we don't link the RTS when linking shared libraries because in the
most usual mode a shared library is an intermediary product, for example a
Haskell library, that will be linked into some executable in the end. So we
wish to defer the RTS flavour to link to the final link.

However sometimes the final product is the shared library, for example when
writing a plugin for some other system, so we do wish the shared library to
link the RTS.

For consistency we also make -staticlib honor this flag and its inversion.
-staticlib currently implies -flink-shared.

- - - - -
c59faf67 by Stefan Schulze Frielinghaus at 2020-07-07T13:56:04-04:00
hadrian: link check-ppr against debugging RTS if ghcDebugged

- - - - -
0effc57d by Adam Sandberg Ericsson at 2020-07-07T13:56:05-04:00
rts linker: teach the linker about GLIBC's special handling of *stat, mknod and atexit functions #7072

- - - - -
96153433 by Adam Sandberg Ericsson at 2020-07-07T13:56:06-04:00
hadrian: make hadrian/ghci use the bootstrap compiler from configure #18190

- - - - -
4d24f886 by Adam Sandberg Ericsson at 2020-07-07T13:56:07-04:00
hadrian: ignore cabal configure verbosity related flags #18131

- - - - -
7332bbff by Ben Gamari at 2020-07-07T13:56:08-04:00
testsuite: Widen T12234 acceptance window to 2%

Previously it wasn't uncommon to see +/-1% fluctuations in compiler
allocations on this test.

- - - - -
180b6313 by Gabor Greif at 2020-07-07T13:56:08-04:00
When running libtool, report it as such
- - - - -
d3bd6897 by Sylvain Henry at 2020-07-07T13:56:11-04:00
BigNum: rename BigNat types

Before this patch BigNat names were confusing because we had:

* GHC.Num.BigNat.BigNat: unlifted type used everywhere else
* GHC.Num.BigNat.BigNatW: lifted type only used to share static constants
* GHC.Natural.BigNat: lifted type only used for backward compatibility

After this patch we have:

* GHC.Num.BigNat.BigNat#: unlifted type
* GHC.Num.BigNat.BigNat: lifted type (reexported from GHC.Natural)

Thanks to @RyanGlScott for spotting this.

- - - - -
929d26db by Sylvain Henry at 2020-07-07T13:56:12-04:00
Bignum: don't build ghc-bignum with stage0

Noticed by @Ericson2314

- - - - -
d25b6851 by Sylvain Henry at 2020-07-07T13:56:12-04:00
Hadrian: ghc-gmp.h shouldn't be a compiler dependency

- - - - -
0ddae2ba by Sylvain Henry at 2020-07-07T13:56:14-04:00
DynFlags: factor out pprUnitId from "Outputable UnitId" instance

- - - - -
204f3f5d by Krzysztof Gogolewski at 2020-07-07T13:56:18-04:00
Remove unused function pprHsForAllExtra (#18423)

The function `pprHsForAllExtra` was called only on `Nothing`
since 2015 (1e041b7382b6aa).

- - - - -
3033e0e4 by Adam Sandberg Ericsson at 2020-07-08T20:36:49-04:00
hadrian: add flag to skip rebuilding dependency information #17636

- - - - -
b7de4b96 by Stefan Schulze Frielinghaus at 2020-07-09T09:49:22-04:00
Fix GHCi :print on big-endian platforms

On big-endian platforms executing

  import GHC.Exts
  data Foo = Foo Float# deriving Show
  foo = Foo 42.0#
  foo
  :print foo

results in an arithmetic overflow exception which is caused by function
index where moveBytes equals
  word_size - (r + item_size_b) * 8
Here we have a mixture of units. Both, word_size and item_size_b have
unit bytes whereas r has unit bits.  On 64-bit platforms moveBytes
equals then
  8 - (0 + 4) * 8
which results in a negative and therefore invalid second parameter for a
shiftL operation.

In order to make things more clear the expression
  (word .&. (mask `shiftL` moveBytes)) `shiftR` moveBytes
is equivalent to
  (word `shiftR` moveBytes) .&. mask
On big-endian platforms the shift must be a left shift instead of a
right shift. For symmetry reasons not a mask is used but two shifts in
order to zero out bits. Thus the fixed version equals
  case endian of
    BigEndian    -> (word `shiftL` moveBits) `shiftR` zeroOutBits `shiftL` zeroOutBits
    LittleEndian -> (word `shiftR` moveBits) `shiftL` zeroOutBits `shiftR` zeroOutBits

Fixes #16548 and #14455

- - - - -
3656dff8 by Sylvain Henry at 2020-07-09T09:50:01-04:00
LLVM: fix MO_S_Mul2 support (#18434)

The value indicating if the carry is useful wasn't taken into account.

- - - - -
d9f09506 by Simon Peyton Jones at 2020-07-10T10:33:44-04:00
Define multiShotIO and use it in mkSplitUniqueSupply

This patch is part of the ongoing eta-expansion saga;
see #18238.

It implements a neat trick (suggested by Sebastian Graf)
that allows the programmer to disable the default one-shot behaviour
of IO (the "state hack").  The trick is to use a new multiShotIO
function; see Note [multiShotIO].  For now, multiShotIO is defined
here in Unique.Supply; but it should ultimately be moved to the IO
library.

The change is necessary to get good code for GHC's unique supply;
see Note [Optimising the unique supply].

However it makes no difference to GHC as-is.  Rather, it makes
a difference when a subsequent commit

   Improve eta-expansion using ArityType

lands.

- - - - -
bce695cc by Simon Peyton Jones at 2020-07-10T10:33:44-04:00
Make arityType deal with join points

As Note [Eta-expansion and join points] describes,
this patch makes arityType deal correctly with join points.
What was there before was not wrong, but yielded lower
arities than it could.

Fixes #18328

In base GHC this makes no difference to nofib.

        Program           Size    Allocs   Runtime   Elapsed  TotalMem
--------------------------------------------------------------------------------
         n-body          -0.1%     -0.1%     -1.2%     -1.1%      0.0%
--------------------------------------------------------------------------------
            Min          -0.1%     -0.1%    -55.0%    -56.5%      0.0%
            Max          -0.0%      0.0%    +16.1%    +13.4%      0.0%
 Geometric Mean          -0.0%     -0.0%    -30.1%    -31.0%     -0.0%

But it starts to make real difference when we land the change to the
way mkDupableAlts handles StrictArg, in fixing #13253 and friends.
I think this is because we then get more non-inlined join points.

- - - - -
2b7c71cb by Simon Peyton Jones at 2020-07-11T12:17:02-04:00
Improve eta-expansion using ArityType

As #18355 shows, we were failing to preserve one-shot info when
eta-expanding.  It's rather easy to fix, by using ArityType more,
rather than just Arity.

This patch is important to suport the one-shot monad trick;
see #18202.  But the extra tracking of one-shot-ness requires
the patch

   Define multiShotIO and use it in mkSplitUniqueSupply

If that patch is missing, ths patch makes things worse in
GHC.Types.Uniq.Supply.  With it, however, we see these improvements

    T3064     compiler bytes allocated -2.2%
    T3294     compiler bytes allocated -1.3%
    T12707    compiler bytes allocated -1.3%
    T13056    compiler bytes allocated -2.2%

Metric Decrease:
    T3064
    T3294
    T12707
    T13056

- - - - -
de139cc4 by Artem Pelenitsyn at 2020-07-12T02:53:20-04:00
add reproducer for #15630

- - - - -
c4de6a7a by Andreas Klebinger at 2020-07-12T02:53:55-04:00
Give Uniq[D]FM a phantom type for its key.

This fixes #17667 and should help to avoid such issues going forward.

The changes are mostly mechanical in nature. With two notable
exceptions.

* The register allocator.

  The register allocator references registers by distinct uniques.
  However they come from the types of VirtualReg, Reg or Unique in
  various places. As a result we sometimes cast the key type of the
  map and use functions which operate on the now typed map but take
  a raw Unique as actual key. The logic itself has not changed it
  just becomes obvious where we do so now.

* <Type>Env Modules.

As an example a ClassEnv is currently queried using the types `Class`,
`Name`, and `TyCon`. This is safe since for a distinct class value all
these expressions give the same unique.

    getUnique cls
    getUnique (classTyCon cls)
    getUnique (className cls)
    getUnique (tcName $ classTyCon cls)

This is for the most part contained within the modules defining the
interface. However it requires us to play dirty when we are given a
`Name` to lookup in a `UniqFM Class a` map. But again the logic did
not change and it's for the most part hidden behind the Env Module.

Some of these cases could be avoided by refactoring but this is left
for future work.

We also bump the haddock submodule as it uses UniqFM.

- - - - -
c2cfdfde by Aaron Allen at 2020-07-13T09:00:33-04:00
Warn about empty Char enumerations (#18402)

Currently the "Enumeration is empty" warning (-Wempty-enumerations)
only fires for numeric literals. This patch adds support for `Char`
literals so that enumerating an empty list of `Char`s will also
trigger the warning.

- - - - -
c3ac87ec by Stefan Schulze Frielinghaus at 2020-07-13T09:01:10-04:00
hadrian: build check-ppr dynamic if GHC is build dynamic

Fixes #18361

- - - - -
9ad072b4 by Simon Peyton Jones at 2020-07-13T14:52:49-04:00
Use dumpStyle when printing inlinings

This just makes debug-printing consistent,
and more informative.

- - - - -
e78c4efb by Simon Peyton Jones at 2020-07-13T14:52:49-04:00
Comments only

- - - - -
7ccb760b by Simon Peyton Jones at 2020-07-13T14:52:49-04:00
Reduce result discount in conSize

Ticket #18282 showed that the result discount given by conSize
was massively too large.  This patch reduces that discount to
a constant 10, which just balances the cost of the constructor
application itself.

Note [Constructor size and result discount] elaborates, as
does the ticket #18282.

Reducing result discount reduces inlining, which affects perf.  I
found that I could increase the unfoldingUseThrehold from 80 to 90 in
compensation; in combination with the result discount change I get
these overall nofib numbers:

        Program           Size    Allocs   Runtime   Elapsed  TotalMem
--------------------------------------------------------------------------------
          boyer          -0.2%     +5.4%     -3.2%     -3.4%      0.0%
       cichelli          -0.1%     +5.9%    -11.2%    -11.7%      0.0%
      compress2          -0.2%     +9.6%     -6.0%     -6.8%      0.0%
   cryptarithm2          -0.1%     -3.9%     -6.0%     -5.7%      0.0%
         gamteb          -0.2%     +2.6%    -13.8%    -14.4%      0.0%
         genfft          -0.1%     -1.6%    -29.5%    -29.9%      0.0%
             gg          -0.0%     -2.2%    -17.2%    -17.8%    -20.0%
           life          -0.1%     -2.2%    -62.3%    -63.4%      0.0%
           mate          +0.0%     +1.4%     -5.1%     -5.1%    -14.3%
         parser          -0.2%     -2.1%     +7.4%     +6.7%      0.0%
      primetest          -0.2%    -12.8%    -14.3%    -14.2%      0.0%
         puzzle          -0.2%     +2.1%    -10.0%    -10.4%      0.0%
            rsa          -0.2%    -11.7%     -3.7%     -3.8%      0.0%
         simple          -0.2%     +2.8%    -36.7%    -38.3%     -2.2%
   wheel-sieve2          -0.1%    -19.2%    -48.8%    -49.2%    -42.9%
--------------------------------------------------------------------------------
            Min          -0.4%    -19.2%    -62.3%    -63.4%    -42.9%
            Max          +0.3%     +9.6%     +7.4%    +11.0%    +16.7%
 Geometric Mean          -0.1%     -0.3%    -17.6%    -18.0%     -0.7%

I'm ok with these numbers, remembering that this change removes
an *exponential* increase in code size in some in-the-wild cases.

I investigated compress2.  The difference is entirely caused by this
function no longer inlining

WriteRoutines.$woutputCodes
  = \ (w :: [CodeEvent]) ->
      let result_s1Sr
            = case WriteRoutines.outputCodes_$s$woutput w 0# 0# 8# 9# of
                (# ww1, ww2 #) -> (ww1, ww2)
      in (# case result_s1Sr of (x, _) ->
              map @Int @Char WriteRoutines.outputCodes1 x
         , case result_s1Sr of { (_, y) -> y } #)

It was right on the cusp before, driven by the excessive result
discount.  Too bad!

Happily, the compiler/perf tests show a number of improvements:
    T12227     compiler bytes-alloc  -6.6%
    T12545     compiler bytes-alloc  -4.7%
    T13056     compiler bytes-alloc  -3.3%
    T15263     runtime  bytes-alloc -13.1%
    T17499     runtime  bytes-alloc -14.3%
    T3294      compiler bytes-alloc  -1.1%
    T5030      compiler bytes-alloc -11.7%
    T9872a     compiler bytes-alloc  -2.0%
    T9872b     compiler bytes-alloc  -1.2%
    T9872c     compiler bytes-alloc  -1.5%

Metric Decrease:
    T12227
    T12545
    T13056
    T15263
    T17499
    T3294
    T5030
    T9872a
    T9872b
    T9872c

- - - - -
7f0b671e by Ben Gamari at 2020-07-13T14:52:49-04:00
testsuite: Widen acceptance threshold on T5837

This test is positively tiny and consequently the bytes allocated
measurement will be relatively noisy. Consequently I have seen this
fail spuriously quite often.

- - - - -
118e1c3d by Alp Mestanogullari at 2020-07-14T21:30:52-04:00
compiler: re-engineer the treatment of rebindable if

Executing on the plan described in #17582, this patch changes the way if expressions
are handled in the compiler in the presence of rebindable syntax. We get rid of the
SyntaxExpr field of HsIf and instead, when rebindable syntax is on, we rewrite the HsIf
node to the appropriate sequence of applications of the local `ifThenElse` function.

In order to be able to report good error messages, with expressions as they were
written by the user (and not as desugared by the renamer), we make use of TTG
extensions to extend GhcRn expression ASTs with an `HsExpansion` construct, which
keeps track of a source (GhcPs) expression and the desugared (GhcRn) expression that
it gives rise to. This way, we can typecheck the latter while reporting the former in
error messages.

In order to discard the error context lines that arise from typechecking the desugared
expressions (because they talk about expressions that the user has not written), we
carefully give a special treatment to the nodes fabricated by this new renaming-time
transformation when typechecking them. See Note [Rebindable syntax and HsExpansion]
for more details. The note also includes a recipe to apply the same treatment to
other rebindable constructs.

Tests 'rebindable11' and 'rebindable12' have been added to make sure we report
identical error messages as before this patch under various circumstances.

We also now disable rebindable syntax when processing untyped TH quotes, as per
the discussion in #18102 and document the interaction of rebindable syntax and
Template Haskell, both in Note [Template Haskell quotes and Rebindable Syntax]
and in the user guide, adding a test to make sure that we do not regress in
that regard.

- - - - -
64c774b0 by Andreas Klebinger at 2020-07-14T21:31:27-04:00
Explain why keeping DynFlags in AnalEnv saves allocation.

- - - - -
254245d0 by Ben Gamari at 2020-07-14T21:32:03-04:00
docs/users-guide: Update default -funfolding-use-threshold value

This was changed in 3d2991f8 but I neglected to update the
documentation. Fixes #18419.

- - - - -
4c259f86 by Andreas Klebinger at 2020-07-14T21:32:41-04:00
Escape backslashes in json profiling reports properly.

I also took the liberty to do away the fixed buffer size for escaping.
Using a fixed size here can only lead to issues down the line.

Fixes #18438.

- - - - -
23797224 by Sergei Trofimovich at 2020-07-14T21:33:19-04:00
.gitlab: re-enable integer-simple substitute (BIGNUM_BACKEND)

Recently build system migrated from INTEGER_LIBRARY to BIGNUM_BACKEND.
But gitlab CI was never updated. Let's enable BIGNUM_BACKEND=native.

Bug: https://gitlab.haskell.org/ghc/ghc/-/issues/18437
Signed-off-by: Sergei Trofimovich <slyfox at gentoo.org>

- - - - -
e0db878a by Sergei Trofimovich at 2020-07-14T21:33:19-04:00
ghc-bignum: bring in sync .hs-boot files with module declarations

Before this change `BIGNUM_BACKEND=native` build was failing as:

```
libraries/ghc-bignum/src/GHC/Num/BigNat/Native.hs:708:16: error:
    * Variable not in scope: naturalFromBigNat# :: WordArray# -> t
    * Perhaps you meant one of these:
        `naturalFromBigNat' (imported from GHC.Num.Natural),
        `naturalToBigNat' (imported from GHC.Num.Natural)
    |
708 |           m' = naturalFromBigNat# m
    |
```

This happens because `.hs-boot` files are slightly out of date.
This change brings in data and function types in sync.

Bug: https://gitlab.haskell.org/ghc/ghc/-/issues/18437
Signed-off-by: Sergei Trofimovich <slyfox at gentoo.org>

- - - - -
c9f65c36 by Stefan Schulze Frielinghaus at 2020-07-14T21:33:57-04:00
rts/Disassembler.c: Use FMT_HexWord for printing values in hex format

- - - - -
58ae62eb by Matthias Andreas Benkard at 2020-07-14T21:34:35-04:00
macOS: Load frameworks without stating them first.

macOS Big Sur makes the following change to how frameworks are shipped
with the OS:

> New in macOS Big Sur 11 beta, the system ships with a built-in
> dynamic linker cache of all system-provided libraries. As part of
> this change, copies of dynamic libraries are no longer present on
> the filesystem. Code that attempts to check for dynamic library
> presence by looking for a file at a path or enumerating a directory
> will fail. Instead, check for library presence by attempting to
> dlopen() the path, which will correctly check for the library in the
> cache. (62986286)

https://developer.apple.com/documentation/macos-release-notes/macos-big-sur-11-beta-release-notes/

Therefore, the previous method of checking whether a library exists
before attempting to load it makes GHC.Runtime.Linker.loadFramework
fail to find frameworks installed at /System/Library/Frameworks.

GHC.Runtime.Linker.loadFramework now opportunistically loads the
framework libraries without checking for their existence first,
failing only if all attempts to load a given framework from any of the
various possible locations fail.

- - - - -
cdc4a6b0 by Matthias Andreas Benkard at 2020-07-14T21:34:35-04:00
loadFramework: Output the errors collected in all loading attempts.

With the recent change away from first finding and then loading a
framework, loadFramework had no way of communicating the real reason
why loadDLL failed if it was any reason other than the framework
missing from the file system.  It now collects all loading attempt
errors into a list and concatenates them into a string to return to
the caller.

- - - - -
51dbfa52 by Ben Gamari at 2020-07-15T04:05:34-04:00
StgToCmm: Use CmmRegOff smart constructor

Previously we would generate expressions of the form
`CmmRegOff BaseReg 0`. This should do no harm (and really should be
handled by the NCG anyways) but it's better to just generate a plain
`CmmReg`.

- - - - -
ae11bdfd by Ben Gamari at 2020-07-15T04:06:08-04:00
testsuite: Add regression test for #17744

Test due to @monoidal.

- - - - -
0e3c277a by Ben Gamari at 2020-07-15T16:41:01-04:00
Bump Cabal submodule

Updates a variety of tests as Cabal is now more strict about Cabal file
form.

- - - - -
ceed994a by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Drop Windows Vista support, require Windows 7

- - - - -
00a23bfd by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Update Windows FileSystem wrapper utilities.

- - - - -
459e1c5f by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Use SlimReaderLocks and ConditonalVariables provided by the OS instead of emulated ones

- - - - -
763088fc by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Small linker comment and ifdef cleanups

- - - - -
1a228ff9 by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Flush event logs eagerly.

- - - - -
e9e04dda by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Refactor Buffer structures to be able to track async operations

- - - - -
356dc3fe by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Implement new Console API

- - - - -
90e69f77 by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Add IOPort synchronization primitive

- - - - -
71245fcc by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Add new io-manager cmdline options

- - - - -
d548a3b3 by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Init Windows console Codepage to UTF-8.

- - - - -
58ef6366 by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Add unsafeSplat to GHC.Event.Array

- - - - -
d660725e by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Add size and iterate to GHC.Event.IntTable.

- - - - -
050da6dd by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Switch Testsuite to test winio by default

- - - - -
4bf542bf by Tamar Christina at 2020-07-15T16:41:01-04:00
winio: Multiple refactorings and support changes.

- - - - -
4489af6b by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: core threaded I/O manager

- - - - -
64d8f2fe by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: core non-threaded I/O manager

- - - - -
8da15a09 by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: Fix a scheduler bug with the threaded-runtime.

- - - - -
84ea3d14 by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: Relaxing some constraints in io-manager.

- - - - -
ccf0d107 by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: Fix issues with non-threaded I/O manager after split.

- - - - -
b492fe6e by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: Remove some barf statements that are a bit strict.

- - - - -
01423fd2 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Expand comments describing non-threaded loop

- - - - -
4b69004f by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: fix FileSize unstat-able handles

- - - - -
9b384270 by Tamar Christina at 2020-07-15T16:41:02-04:00
winio: Implement new tempfile routines for winio

- - - - -
f1e0be82 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Fix input truncation when reading from handle.

This was caused by not upholding the read buffer invariant
that bufR == bufL == 0 for empty read buffers.

- - - - -
e176b625 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Fix output truncation for writes larger than buffer size

- - - - -
a831ce0e by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Rewrite bufWrite.

I think it's far easier to follow the code now.
It's also correct now as I had still missed a spot
where we didn't update the offset.

- - - - -
6aefdf62 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Fix offset set by bufReadEmpty.

bufReadEmpty returns the bytes read *including* content that
was already buffered,
But for calculating the offset we only care about the number
of bytes read into the new buffer.

- - - - -
750ebaee by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Clean up code surrounding IOPort primitives.

According to phyx these should only be read and written once per
object. Not neccesarily in that order.

To strengthen that guarantee the primitives will now throw an
exception if we violate this invariant.

As a consequence we can eliminate some code from their primops.
In particular code dealing with multiple queued readers/writers
now simply checks the invariant and throws an exception if it
was violated. That is in contrast to mvars which will do things
like wake up all readers, queue multi writers etc.

- - - - -
ffd31db9 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Fix multi threaded threadDelay and a few other small changes.

Multithreaded threadDelay suffered from a race condition
based on the ioManagerStatus. Since the status isn't needed
for WIO I removed it completely.

This resulted in a light refactoring, as consequence we will always
wake up the IO manager using interruptSystemManager, which uses
`postQueuedCompletionStatus` internally.

I also added a few comments which hopefully makes the code easier to
dive into for the next person diving in.

- - - - -
6ec26df2 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
wionio: Make IO subsystem check a no-op on non-windows platforms.

- - - - -
29bcd936 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Set handle offset when opening files in Append mode.

Otherwise we would truncate the file.

- - - - -
55c29700 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Remove debug event log trace

- - - - -
9acb9f40 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Fix sqrt and openFile009 test cases

- - - - -
57017cb7 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Allow hp2ps to build with -DDEBUG

- - - - -
b8cd9995 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Update output of T9681 since we now actually run it.

- - - - -
10af5b14 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: A few more improvements to the IOPort primitives.

- - - - -
39afc4a7 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Fix expected tempfiles output.

Tempfiles now works properly on windows, as such we can
delete the win32 specific output.

- - - - -
99db46e0 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Assign thread labels to IOManager threads.

- - - - -
be6af732 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Properly check for the tso of an incall to be zero.

- - - - -
e2c6dac7 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Mark FD instances as unsupported under WINIO.

- - - - -
fd02ceed by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Fix threadDelay maxBound invocations.

Instead of letting the ns timer overflow now clamp it at
(maxBound :: Word64) ns. That still gives a few hundred
years.

- - - - -
bc79f9f1 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Add comments/cleanup an import in base

- - - - -
1d197f4b by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Mark outstanding_service_requests volatile.

As far as I know C(99) gives no guarantees for code like

    bool condition;

    ...

    while(condition)
        sleep();

that condition will be updated if it's changed by another thread.
So we are explicit here and mark it as volatile, this will force
a reload from memory on each iteration.

- - - - -
dc438186 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Make last_event a local variable

- - - - -
2fc957c5 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Add comment about thread safety of processCompletion.

- - - - -
4c026b6c by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: nonthreaded: Create io processing threads in main thread.

We now set a flag in the IO thread. The scheduler when looking for work
will check the flag and create/queue threads accordingly.

We used to create these in the IO thread. This improved performance
but caused frequent segfaults. Thread creation/allocation is only safe to
do if nothing currently accesses the storeagemanager. However without
locks in the non-threaded runtime this can't be guaranteed.

This shouldn't change performance all too much.

In the past we had:
* IO: Create/Queue thread.
* Scheduler: Runs a few times. Eventually picks up IO processing thread.

Now it's:
* IO: Set flag to queue thread.
* Scheduler: Pick up flag, if set create/queue thread. Eventually picks up IO processing thread.

- - - - -
f47c7208 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Add an exported isHeapAlloced function to the RTS

- - - - -
cc5d7bb1 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Queue IO processing threads at the front of the queue.

This will unblock the IO thread sooner hopefully leading to higher
throughput in some situations.

- - - - -
e7630115 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: ThreadDelay001: Use higher resolution timer.

- - - - -
451b5f96 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Update T9681 output, disable T4808 on windows.

T4808 tests functionality of the FD interface which won't be supported
under WINIO.

T9681 just has it's expected output tweaked.

- - - - -
dd06f930 by Andreas Klebinger at 2020-07-15T16:41:02-04:00
winio: Wake io manager once per registerTimeout.

Which is implicitly done in editTimeouts, so need to wake it
up twice.

- - - - -
e87d0bf9 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Update placeholder comment with actual function name.

- - - - -
fc9025db by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Always lock win32 event queue

- - - - -
c24c9a1f by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Display thread labels when tracing scheduler events.

- - - - -
06542b03 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Refactor non-threaded runner thread and scheduler interface.

Only use a single communication point (registerAlertableWait) to inform
the C side aobut both timeouts to use as well as outstanding requests.

Also queue a haskell processing thread after each return from alertable
waits. This way there is no risk of us missing a timer event.

- - - - -
256299b1 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Remove outstanding_requests from runner.

We used a variable to keep track of situations where we got
entries from the IO port, but all of them had already been
canceled. While we can avoid some work that way this case
seems quite rare.

So we give up on tracking this and instead always assume at
least one of the returned entries is valid.

If that's not the case no harm is done, we just perform some
additional work. But it makes the runner easier to reason about.

In particular we don't need to care if another thread modifies
oustanding_requests after we return from waiting on the IO Port.

- - - - -
3ebd8ad9 by Tamar Christina at 2020-07-15T16:41:03-04:00
winio: Various fixes related to rebase and testdriver

- - - - -
6be6bcba by Tamar Christina at 2020-07-15T16:41:03-04:00
winio: Fix rebase artifacts

- - - - -
2c649dc3 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Rename unsafeSplat to unsafeCopyFromBuffer

- - - - -
a18b73f3 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Remove unused size/iterate operations from IntTable

- - - - -
16bab48e by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Detect running IO Backend via peeking at RtsConfig

- - - - -
8b8405a0 by Tamar Christina at 2020-07-15T16:41:03-04:00
winio: update temp path so GCC etc can handle it.

Also fix PIPE support, clean up error casting, fix memory leaks

- - - - -
2092bc54 by Ben Gamari at 2020-07-15T16:41:03-04:00
winio: Minor comments/renamings

- - - - -
a5b5b6c0 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Checking if an error code indicates completion is now a function.

- - - - -
362176fd by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Small refactor in withOverlappedEx

- - - - -
32e20597 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: A few comments and commented out dbxIO

- - - - -
a4bfc1d9 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Don't drop buffer offset in byteView/cwcharView

- - - - -
b3ad2a54 by Tamar Christina at 2020-07-15T16:41:03-04:00
winio: revert BHandle changes.

- - - - -
3dcd87e2 by Ben Gamari at 2020-07-15T16:41:03-04:00
winio: Fix imports

- - - - -
5a371890 by Tamar Christina at 2020-07-15T16:41:03-04:00
winio: update ghc-cabal to handle new Cabal submodule bump

- - - - -
d07ebe0d by Ben Gamari at 2020-07-15T16:41:03-04:00
winio: Only compile sources on Windows

- - - - -
dcb42393 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Actually return Nothing on EOF for non-blocking read

- - - - -
895a3beb by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Deduplicate logic in encodeMultiByte[Raw]IO.

- - - - -
e06e6734 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Deduplicate openFile logic

- - - - -
b59430c0 by Tamar Christina at 2020-07-15T16:41:03-04:00
winio: fix -werror issue in encoding file

- - - - -
f8d39a51 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Don't mention windows specific functions when building on Linux.

- - - - -
6a533d2a by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: add a note about file locking in the RTS.

- - - - -
cf37ce34 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Add version to @since annotation

- - - - -
0fafa2eb by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Rename GHC.Conc.IOCP -> GHC.Conc.WinIO

- - - - -
1854fc23 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Expand GHC.Conc.POSIX description

It now explains users may not use these functions when
using the old IO manager.

- - - - -
fcc7ba41 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Fix potential spaceleak in __createUUIDTempFileErrNo

- - - - -
6b3fd9fa by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Remove redundant -Wno-missing-signatures pragmas

- - - - -
916fc861 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Make it explicit that we only create one IO manager

- - - - -
f260a721 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Note why we don't use blocking waits.

- - - - -
aa0a4bbf by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Remove commented out pragma

- - - - -
d679b544 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Remove redundant buffer write in Handle/Text.hs:bufReadEmpty

- - - - -
d3f94368 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Rename SmartHandles to StdHandles

- - - - -
bd6b8ec1 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: add comment stating failure behaviour for getUniqueFileInfo.

- - - - -
12846b85 by Andreas Klebinger at 2020-07-15T16:41:03-04:00
winio: Update IOPort haddocks.

- - - - -
9f39fb14 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Add a note cross reference

- - - - -
62dd5a73 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Name Haskell/OS I/O Manager explicitly in Note

- - - - -
fa807828 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Expand BlockedOnIOCompletion description.

- - - - -
f0880a1d by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Remove historical todos

- - - - -
8e58e714 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Update note, remove debugging pragma.

- - - - -
aa4d84d5 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: flushCharReadBuffer shouldn't need to adjust offsets.

- - - - -
e580893a by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Remove obsolete comment about cond. variables

- - - - -
d54e9d79 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: fix initial linux validate build

- - - - -
3cd4de46 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Fix ThreadDelay001 CPP

- - - - -
c88b1b9f by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Fix openFile009 merge conflict leftover

- - - - -
849e8889 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Accept T9681 output.

GHC now reports String instead of [Char].

- - - - -
e7701818 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Fix cabal006 after upgrading cabal submodule

Demand cabal 2.0 syntax instead of >= 1.20 as required by newer cabal versions.

- - - - -
a44f0373 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Fix stderr output for ghci/linking/dyn tests.

We used to filter rtsopts, i opted to instead just accept the warning of it having no effect.
This works both for -rtsopts, as well as -with-rtsopts which winio adds.

- - - - -
515d9896 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Adjust T15261b stdout for --io-manager flag.

- - - - -
949aaacc by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Adjust T5435_dyn_asm stderr

The warning about rtsopts having no consequences is expected.
So accept new stderr.

- - - - -
7d424e1e by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Also accept T7037 stderr

- - - - -
1f009768 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: fix cabal04 by filtering rts args

- - - - -
981a9f2e by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: fix cabal01 by accepting expected stderr

- - - - -
b7b0464e by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: fix safePkg01 by accepting expected stderr

- - - - -
32734b29 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: fix T5435_dyn_gcc by accepting expected stderr

- - - - -
acc5cebf by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: fix tempfiles test on linux

- - - - -
c577b789 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Accept accepted stderr for T3807

- - - - -
c108c527 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Accept accepted stderr for linker_unload

- - - - -
2b0b9a08 by Andreas Klebinger at 2020-07-15T16:41:04-04:00
winio: Accept accepted stderr for linker_unload_multiple_objs

- - - - -
67afb03c by Tamar Christina at 2020-07-15T16:41:04-04:00
winio: clarify wording on conditional variables.

- - - - -
3bd41572 by Tamar Christina at 2020-07-15T16:41:04-04:00
winio: clarify comment on cooked mode.

- - - - -
ded58a03 by Tamar Christina at 2020-07-15T16:41:04-04:00
winio: update lockfile signature and remove mistaken symbol in rts.

- - - - -
2143c492 by Ben Gamari at 2020-07-15T16:41:04-04:00
testsuite: Add winio and winio_threaded ways

Reverts many of the testsuite changes

- - - - -
c0979cc5 by Ben Gamari at 2020-07-16T10:56:54-04:00
Merge remote-tracking branch 'origin/wip/winio'

- - - - -
750a1595 by Ben Gamari at 2020-07-18T07:26:41-04:00
rts: Add --copying-gc flag to reverse effect of --nonmoving-gc

Fixes #18281.

- - - - -
6ba6a881 by Hécate at 2020-07-18T07:26:42-04:00
Implement `fullCompilerVersion`

Follow-up of https://gitlab.haskell.org/ghc/ghc/-/issues/18403

This MR adds `fullCompilerVersion`, a function that shares the same
backend as the `--numeric-version` GHC flag, exposing a full,
three-digit version datatype.

- - - - -
e6cf27df by Hécate at 2020-07-18T07:26:43-04:00
Add a Lint hadrian rule and an .hlint.yaml file in base/

- - - - -
bcb177dd by Simon Peyton Jones at 2020-07-18T07:26:43-04:00
Allow multiple case branches to have a higher rank type

As #18412 points out, it should be OK for multiple case alternatives
to have a higher rank type, provided they are all the same.

This patch implements that change.  It sweeps away
GHC.Tc.Gen.Match.tauifyMultipleBranches, and friends, replacing it
with an enhanced version of fillInferResult.

The basic change to fillInferResult is to permit the case in which
another case alternative has already filled in the result; and in
that case simply unify.  It's very simple actually.

See the new Note [fillInferResult] in TcMType

Other refactoring:

- Move all the InferResult code to one place, in GHC.Tc.Utils.TcMType
  (previously some of it was in Unify)

- Move tcInstType and friends from TcMType to Instantiate, where it
  more properly belongs.  (TCMType was getting very long.)

- - - - -
e5525a51 by Simon Peyton Jones at 2020-07-18T07:26:43-04:00
Improve typechecking of NPlusK patterns

This patch (due to Richard Eisenberg) improves
documentation of the wrapper returned by tcSubMult
(see Note [Wrapper returned from tcSubMult] in
 GHC.Tc.Utils.Unify).

And, more substantially, it cleans up the multiplicity
handling in the typechecking of NPlusKPat

- - - - -
12f90352 by Krzysztof Gogolewski at 2020-07-18T07:26:45-04:00
Remove {-# CORE #-} pragma (part of #18048)

This pragma has no effect since 2011.
It was introduced for External Core, which no longer exists.

Updates haddock submodule.

- - - - -
e504c913 by Simon Peyton Jones at 2020-07-18T07:26:45-04:00
Refactor the simplification of join binders

This MR (for #18449) refactors the Simplifier's treatment
of join-point binders.

Specifically, it puts together, into
     GHC.Core.Opt.Simplify.Env.adjustJoinPointType
two currently-separate ways in which we adjust the type of
a join point. As the comment says:

-- (adjustJoinPointType mult new_res_ty join_id) does two things:
--
--   1. Set the return type of the join_id to new_res_ty
--      See Note [Return type for join points]
--
--   2. Adjust the multiplicity of arrows in join_id's type, as
--      directed by 'mult'. See Note [Scaling join point arguments]

I think this actually fixes a latent bug, by ensuring that the
seIdSubst and seInScope have the right multiplicity on the type
of join points.

I did some tidying up while I was at it.  No more
setJoinResTy, or modifyJoinResTy: instead it's done locally in
Simplify.Env.adjustJoinPointType

- - - - -
49b265f0 by Chaitanya Koparkar at 2020-07-18T07:26:46-04:00
Fix minor typos in a Core.hs note

- - - - -
8d59aed6 by Stefan Schulze Frielinghaus at 2020-07-18T07:26:47-04:00
GHCi: Fix isLittleEndian

- - - - -
c26e81d1 by Ben Gamari at 2020-07-18T07:26:47-04:00
testsuite: Mark ghci tests as fragile under unreg compiler

In particular I have seen T16012 fail repeatedly under the
unregisterised compiler.

- - - - -
868e4523 by Moritz Angermann at 2020-07-20T04:30:38-04:00
Revert "AArch32 symbols only on aarch32."

This reverts commit cdfeb3f24f76e8fd30452016676e56fbc827789a.

Signed-off-by: Moritz Angermann <moritz.angermann at gmail.com>

- - - - -
c915ba84 by Moritz Angermann at 2020-07-20T04:30:38-04:00
Revert "Fix (1)"

This reverts commit 7abffced01f5680efafe44f6be2733eab321b039.

Signed-off-by: Moritz Angermann <moritz.angermann at gmail.com>

- - - - -
777c452a by Moritz Angermann at 2020-07-20T04:30:38-04:00
Revert "better if guards."

This reverts commit 3f60b94de1f460ca3f689152860b108a19ce193e.

Signed-off-by: Moritz Angermann <moritz.angermann at gmail.com>

- - - - -
0dd40552 by Moritz Angermann at 2020-07-20T04:30:38-04:00
Revert "[linker/rtsSymbols] More linker symbols"

This reverts commit 686e72253aed3880268dd6858eadd8c320f09e97.

Signed-off-by: Moritz Angermann <moritz.angermann at gmail.com>

- - - - -
30caeee7 by Sylvain Henry at 2020-07-21T06:39:33-04:00
DynFlags: remove use of sdocWithDynFlags from GHC.Stg.* (#17957)

* add StgPprOpts datatype
* remove Outputable instances for types that need `StgPprOpts` to be
  pretty-printed and explicitly call type specific ppr functions
* add default `panicStgPprOpts` for panic messages (when it's not
  convenient to thread StgPprOpts or DynFlags down to the ppr function
  call)

- - - - -
863c544c by Mark at 2020-07-21T06:39:34-04:00
Fix a typo in existential_quantification.rst
- - - - -
05910be1 by Krzysztof Gogolewski at 2020-07-21T14:47:07-04:00
Add release notes entry for #17816

[skip ci]

- - - - -
a6257192 by Matthew Pickering at 2020-07-21T14:47:19-04:00
Use a newtype `Code` for the return type of typed quotations (Proposal #195)

There are three problems with the current API:

1. It is hard to properly write instances for ``Quote m => m (TExp a)`` as the type is the composition
   of two type constructors. Doing so in your program involves making your own newtype and
   doing a lot of wrapping/unwrapping.

   For example, if I want to create a language which I can either run immediately or
   generate code from I could write the following with the new API. ::

      class Lang r where
        _int :: Int -> r Int
        _if  :: r Bool -> r a -> r a -> r a

      instance Lang Identity where
        _int = Identity
        _if (Identity b) (Identity t) (Identity f) = Identity (if b then t else f)

      instance Quote m => Lang (Code m) where
        _int = liftTyped
        _if cb ct cf = [|| if $$cb then $$ct else $$cf ||]

2. When doing code generation it is common to want to store code fragments in
   a map. When doing typed code generation, these code fragments contain a
   type index so it is desirable to store them in one of the parameterised
   map data types such as ``DMap`` from ``dependent-map`` or ``MapF`` from
   ``parameterized-utils``.

   ::

      compiler :: Env -> AST a -> Code Q a

      data AST a where ...
      data Ident a = ...

      type Env = MapF Ident (Code Q)

      newtype Code m a = Code (m (TExp a))

   In this example, the ``MapF`` maps an ``Ident String`` directly to a ``Code Q String``.
   Using one of these map types currently requires creating your own newtype and constantly
   wrapping every quotation and unwrapping it when using a splice. Achievable, but
   it creates even more syntactic noise than normal metaprogramming.

3. ``m (TExp a)`` is ugly to read and write, understanding ``Code m a`` is
   easier. This is a weak reason but one everyone
   can surely agree with.

Updates text submodule.

- - - - -
58235d46 by Ben Gamari at 2020-07-21T14:47:28-04:00
users-guide: Fix :rts-flag:`--copying-gc` documentation

It was missing a newline.

- - - - -
19e80b9a by Vladislav Zavialov at 2020-07-21T14:50:01-04:00
Accumulate Haddock comments in P (#17544, #17561, #8944)

Haddock comments are, first and foremost, comments. It's very annoying
to incorporate them into the grammar. We can take advantage of an
important property: adding a Haddock comment does not change the parse
tree in any way other than wrapping some nodes in HsDocTy and the like
(and if it does, that's a bug).

This patch implements the following:

* Accumulate Haddock comments with their locations in the P monad.
  This is handled in the lexer.

* After parsing, do a pass over the AST to associate Haddock comments
  with AST nodes using location info.

* Report the leftover comments to the user as a warning (-Winvalid-haddock).

- - - - -
4c719460 by David Binder at 2020-07-22T20:17:35-04:00
Fix dead link to haskell prime discussion

- - - - -
f2f817e4 by BinderDavid at 2020-07-22T20:17:35-04:00
Replace broken links to old haskell-prime site by working links to gitlab instance.
[skip ci]

- - - - -
0bf8980e by Daniel Gröber at 2020-07-22T20:18:11-04:00
Remove length field from FastString

- - - - -
1010c33b by Daniel Gröber at 2020-07-22T20:18:11-04:00
Use ShortByteString for FastString

There are multiple reasons we want this:

- Fewer allocations: ByteString has 3 fields, ShortByteString just has one.
- ByteString memory is pinned:
  - This can cause fragmentation issues (see for example #13110) but also
  - makes using FastStrings in compact regions impossible.

Metric Decrease:
    T5837
    T12150
    T12234
    T12425

- - - - -
8336ba78 by Daniel Gröber at 2020-07-22T20:18:11-04:00
Pass specialised utf8DecodeChar# to utf8DecodeLazy# for performance

Currently we're passing a indexWord8OffAddr# type function to
utf8DecodeLazy# which then passes it on to utf8DecodeChar#. By passing one
of utf8DecodeCharAddr# or utf8DecodeCharByteArray# instead we benefit from
the inlining and specialization already done for those.

- - - - -
7484a9a4 by Daniel Gröber at 2020-07-22T20:18:11-04:00
Encoding: Add comment about tricky ForeignPtr lifetime

- - - - -
5536ed28 by Daniel Gröber at 2020-07-22T20:18:11-04:00
Use IO constructor instead of `stToIO . ST`

- - - - -
5b8902e3 by Daniel Gröber at 2020-07-22T20:18:11-04:00
Encoding: Remove redundant use of withForeignPtr

- - - - -
5976a161 by Daniel Gröber at 2020-07-22T20:18:11-04:00
Encoding: Reformat utf8EncodeShortByteString to be more consistent

- - - - -
9ddf1614 by Daniel Gröber at 2020-07-22T20:18:11-04:00
FastString: Reintroduce character count cache

Metric Increase:
    ManyConstructors

Metric Decrease:
    T4029

- - - - -
e9491668 by Ben Gamari at 2020-07-22T20:18:46-04:00
get-win32-tarballs: Fix detection of missing tarballs

This fixes the error message given by configure when the user
attempts to configure without first download the win32 tarballs.

- - - - -
9f3ff8fd by Andreas Klebinger at 2020-07-22T20:19:22-04:00
Enable BangPatterns, ScopedTypeVariables for ghc and hadrian by default.

This is only for their respective codebases.

- - - - -
0f17b930 by Sylvain Henry at 2020-07-22T20:19:59-04:00
Remove unused "ncg" flag

This flag has been removed in 066b369de2c6f7da03c88206288dca29ab061b31
in 2011.

- - - - -
bab4ec8f by Sylvain Henry at 2020-07-22T20:19:59-04:00
Don't panic if the NCG isn't built (it is always built)

- - - - -
8ea33edb by Sylvain Henry at 2020-07-22T20:19:59-04:00
Remove unused sGhcWithNativeCodeGen

- - - - -
e079bb72 by Sylvain Henry at 2020-07-22T20:19:59-04:00
Correctly test active backend

Previously we used a platform settings to detect if the native code
generator was used. This was wrong. We need to use the
`DynFlags.hscTarget` field instead.

- - - - -
735f9d6b by Sylvain Henry at 2020-07-22T20:19:59-04:00
Replace ghcWithNativeCodeGen with a proper Backend datatype

* Represent backends with a `Backend` datatype in GHC.Driver.Backend

* Don't detect the default backend to use for the target platform at
  compile time in Hadrian/make but at runtime. It makes "Settings"
  simpler and it is a step toward making GHC multi-target.

* The latter change also fixes hadrian which has not been updated to
  take into account that the NCG now supports AIX and PPC64 (cf
  df26b95559fd467abc0a3a4151127c95cb5011b9 and
  d3c1dda60d0ec07fc7f593bfd83ec9457dfa7984)

* Also we don't treat iOS specifically anymore (cf
  cb4878ffd18a3c70f98bdbb413cd3c4d1f054e1f)

- - - - -
f7cc4313 by Sylvain Henry at 2020-07-22T20:19:59-04:00
Replace HscTarget with Backend

They both have the same role and Backend name is more explicit.

Metric Decrease:
    T3064

Update Haddock submodule

- - - - -
15ce1804 by Andreas Klebinger at 2020-07-22T20:20:34-04:00
Deprecate -fdmd-tx-dict-sel.

It's behaviour is now unconditionally enabled as
it's slightly beneficial.

There are almost no benchmarks which benefit from
disabling it, so it's not worth the keep this
configurable.

This fixes #18429.

- - - - -
ff1b7710 by Sylvain Henry at 2020-07-22T20:21:11-04:00
Add test for #18064

It has been fixed by 0effc57d48ace6b719a9f4cbeac67c95ad55010b

- - - - -
cfa89149 by Krzysztof Gogolewski at 2020-07-22T20:21:48-04:00
Define type Void# = (# #) (#18441)

There's one backwards compatibility issue: GHC.Prim no longer exports
Void#, we now manually re-export it from GHC.Exts.

- - - - -
02f40b0d by Sebastian Graf at 2020-07-22T20:22:23-04:00
Add regression test for #18478

!3392 backported !2993 to GHC 8.10.2 which most probably is responsible
for fixing #18478, which triggered a pattern match checker performance
regression in GHC 8.10.1 as first observed in #17977.

- - - - -
7f44df1e by Sylvain Henry at 2020-07-22T20:23:00-04:00
Minor refactoring of Unit display

* for consistency, try to always use UnitPprInfo to display units to
  users

* remove some uses of `unitPackageIdString` as it doesn't show the
  component name and it uses String

- - - - -
dff1cb3d by Moritz Angermann at 2020-07-23T07:55:29-04:00
[linker] Fix out of range relocations.

mmap may return address all over the place. mmap_next will ensure we get
the next free page after the requested address.

This is especially important for linking on aarch64, where the memory model with PIC
admits relocations in the +-4GB range, and as such we can't work with
arbitrary object locations in memory.

Of note: we map the rts into process space, so any mapped objects must
not be ouside of the 4GB from the processes address space.

- - - - -
cdd0ff16 by Tamar Christina at 2020-07-24T18:12:23-04:00
winio: restore console cp on exit

- - - - -
c1f4f81d by Tamar Christina at 2020-07-24T18:13:00-04:00
winio: change memory allocation strategy and fix double free errors.

- - - - -
ba205046 by Simon Peyton Jones at 2020-07-24T18:13:35-04:00
Care with occCheckExpand in kind of occurrences

Issue #18451 showed that we could get an infinite type, through
over-use of occCheckExpand in the kind of an /occurrence/ of a
type variable.

See Note [Occurrence checking: look inside kinds] in GHC.Core.Type

This patch fixes the problem by making occCheckExpand less eager
to expand synonyms in kinds.

It also improves pretty printing of kinds, by *not* suppressing
the kind on a tyvar-binder like
    (a :: Const Type b)
where type Const p q = p.  Even though the kind of 'a' is Type,
we don't want to suppress the kind ascription.  Example: the
error message for polykinds/T18451{a,b}. See GHC.Core.TyCo.Ppr
Note [Suppressing * kinds].

- - - - -
02133353 by Zubin Duggal at 2020-07-25T00:44:30-04:00
Simplify XRec definition
Change `Located X` usage to `XRec pass X`
This increases the scope of the LPat experiment to almost all of GHC.
Introduce UnXRec and MapXRec classes

Fixes #17587 and #18408

Updates haddock submodule

Co-authored-by: Philipp Krüger <philipp.krueger1 at gmail.com>

- - - - -
e443846b by Sylvain Henry at 2020-07-25T00:45:07-04:00
DynFlags: store printer in TraceBinIfaceReading

We don't need to pass the whole DynFlags, just pass the logging
function, if any.

- - - - -
15b2b44f by Sylvain Henry at 2020-07-25T00:45:08-04:00
Rename GHC.Driver.Ways into GHC.Platform.Ways

- - - - -
342a01af by Sylvain Henry at 2020-07-25T00:45:08-04:00
Add GHC.Platform.Profile

- - - - -
6333d739 by Sylvain Henry at 2020-07-25T00:45:08-04:00
Put PlatformConstants into Platform

- - - - -
9dfeca6c by Sylvain Henry at 2020-07-25T00:45:08-04:00
Remove platform constant wrappers

Platform constant wrappers took a DynFlags parameter, hence implicitly
used the target platform constants. We removed them to allow support
for several platforms at once (#14335) and to avoid having to pass
the full DynFlags to every function (#17957).

Metric Decrease:
   T4801

- - - - -
73145d57 by Sylvain Henry at 2020-07-25T00:45:08-04:00
Remove dead code in utils/derivConstants

- - - - -
7721b923 by Sylvain Henry at 2020-07-25T00:45:08-04:00
Move GHC.Platform into the compiler

Previously it was in ghc-boot so that ghc-pkg could use it. However it
wasn't necessary because ghc-pkg only uses a subset of it: reading
target arch and OS from the settings file. This is now done via
GHC.Platform.ArchOS (was called PlatformMini before).

- - - - -
459afeb5 by Sylvain Henry at 2020-07-25T00:45:08-04:00
Fix build systems

- - - - -
9e2930c3 by Sylvain Henry at 2020-07-25T00:45:08-04:00
Bump CountParserDeps

- - - - -
6e2db34b by Sylvain Henry at 2020-07-25T00:45:08-04:00
Add accessors to ArchOS

- - - - -
fc0f6fbc by Stefan Schulze Frielinghaus at 2020-07-25T00:45:45-04:00
Require SMP support in order to build a threaded stage1

Fixes 18266

- - - - -
a7c4439a by Matthias Andreas Benkard at 2020-07-26T13:23:24-04:00
Document loadFramework changes. (#18446)

Adds commentary on the rationale for the changes made in merge request
!3689.

- - - - -
da7269a4 by Ben Gamari at 2020-07-26T13:23:59-04:00
rts/win32: Exit with EXIT_HEAPOVERFLOW if memory commit fails

Since switching to the two-step allocator, the `outofmem` test fails via
`osCommitMemory` failing to commit. However, this was previously exiting
with `EXIT_FAILURE`, rather than `EXIT_HEAPOVERFLOW`. I think the latter
is a more reasonable exit code for this case and matches the behavior on
POSIX platforms.

- - - - -
f153a1d0 by Ben Gamari at 2020-07-26T13:23:59-04:00
testsuite: Update win32 output for parseTree

- - - - -
e91672f0 by Ben Gamari at 2020-07-26T13:23:59-04:00
testsuite: Normalise WinIO error message differences

Previously the old Windows IO manager threw different errors than WinIO.
We now canonicalise these to the WinIO errors.

- - - - -
9cbfe086 by Ben Gamari at 2020-07-26T13:23:59-04:00
gitlab-ci: Kill ssh-agent after pushing test metrics

Otherwise the Windows builds hang forever waiting for the process to
terminate.

- - - - -
8236925f by Tamar Christina at 2020-07-26T13:24:35-04:00
winio: remove dead argument to stg_newIOPortzh

- - - - -
ce0a1d67 by Tamar Christina at 2020-07-26T13:25:11-04:00
winio: fix detection of tty terminals

- - - - -
52685cf7 by Tamar Christina at 2020-07-26T13:25:48-04:00
winio: update codeowners

- - - - -
aee45d9e by Vladislav Zavialov at 2020-07-27T07:06:56-04:00
Improve NegativeLiterals (#18022, GHC Proposal #344)

Before this patch, NegativeLiterals used to parse x-1 as x (-1).

This may not be what the user expects, and now it is fixed:
x-1 is parsed as (-) x 1.

We achieve this by the following requirement:

  * When lexing a negative literal,
    it must not be preceded by a 'closing token'.

This also applies to unboxed literals, e.g. -1#.

See GHC Proposal #229 for the definition of a closing token.

A nice consequence of this change is that -XNegativeLiterals becomes a
subset of -XLexicalNegation. In other words, enabling both of those
extensions has the same effect as enabling -XLexicalNegation alone.

- - - - -
667ab69e by leiftw at 2020-07-27T07:07:32-04:00
fix typo referring to non-existent `-ohidir` flag, should be `-hidir` I think
- - - - -
6ff89c17 by Vladislav Zavialov at 2020-07-27T07:08:07-04:00
Refactor the parser a little

* Create a dedicated production for type operators
* Create a dedicated type for the UNPACK pragma
* Remove an outdated part of Note [Parsing data constructors is hard]

- - - - -
aa054d32 by Ben Gamari at 2020-07-27T20:09:07-04:00
Drop 32-bit Windows support

As noted in #18487, we have reached the end of this road.

- - - - -
6da73bbf by Michalis Pardalos at 2020-07-27T20:09:44-04:00
Add minimal test for #12492

- - - - -
47680cb7 by Michalis Pardalos at 2020-07-27T20:09:44-04:00
Use allocate, not ALLOC_PRIM_P for unpackClosure#

ALLOC_PRIM_P fails for large closures, by directly using allocate
we can handle closures which are larger than the block size.

Fixes #12492

- - - - -
3d345c96 by Simon Peyton Jones at 2020-07-27T20:10:19-04:00
Eta-expand the Simplifier monad

This patch eta-expands the Simplifier's monad, using the method
explained in GHC.Core.Unify Note [The one-shot state monad trick].
It's part of the exta-expansion programme in #18202.

It's a tiny patch, but is worth a 1-2% reduction in bytes-allocated
by the compiler.  Here's the list, based on the compiler-performance
tests in perf/compiler:

                    Reduction in bytes allocated
   T10858(normal)      -0.7%
   T12425(optasm)      -1.3%
   T13056(optasm)      -1.8%
   T14683(normal)      -1.1%
   T15164(normal)      -1.3%
   T15630(normal)      -1.4%
   T17516(normal)      -2.3%
   T18282(normal)      -1.6%
   T18304(normal)      -0.8%
   T1969(normal)       -0.6%
   T4801(normal)       -0.8%
   T5321FD(normal)     -0.7%
   T5321Fun(normal)    -0.5%
   T5642(normal)       -0.9%
   T6048(optasm)       -1.1%
   T9020(optasm)       -2.7%
   T9233(normal)       -0.7%
   T9675(optasm)       -0.5%
   T9961(normal)       -2.9%
   WWRec(normal)       -1.2%

Metric Decrease:
    T12425
    T9020
    T9961

- - - - -
57aca6bb by Ben Gamari at 2020-07-27T20:10:54-04:00
gitlab-ci: Ensure that Hadrian jobs don't download artifacts

Previously the Hadrian jobs had the default dependencies, meaning that
they would download artifacts from all jobs of earlier stages. This is
unneccessary.

- - - - -
0a815cea by Ben Gamari at 2020-07-27T20:10:54-04:00
gitlab-ci: Bump bootstrap compiler to 8.8.4

Hopefully this will make the Windows jobs a bit more reliable.

- - - - -
0bd60059 by Simon Peyton Jones at 2020-07-28T02:01:49-04:00
This patch addresses the exponential blow-up in the simplifier.

Specifically:
  #13253 exponential inlining
  #10421 ditto
  #18140 strict constructors
  #18282 another nested-function call case

This patch makes one really significant changes: change the way that
mkDupableCont handles StrictArg.  The details are explained in
GHC.Core.Opt.Simplify Note [Duplicating StrictArg].

Specific changes

* In mkDupableCont, when making auxiliary bindings for the other arguments
  of a call, add extra plumbing so that we don't forget the demand on them.
  Otherwise we haev to wait for another round of strictness analysis. But
  actually all the info is to hand.  This change affects:
  - Make the strictness list in ArgInfo be [Demand] instead of [Bool],
    and rename it to ai_dmds.
  - Add as_dmd to ValArg
  - Simplify.makeTrivial takes a Demand
  - mkDupableContWithDmds takes a [Demand]

There are a number of other small changes

1. For Ids that are used at most once in each branch of a case, make
   the occurrence analyser record the total number of syntactic
   occurrences.  Previously we recorded just OneBranch or
   MultipleBranches.

   I thought this was going to be useful, but I ended up barely
   using it; see Note [Note [Suppress exponential blowup] in
   GHC.Core.Opt.Simplify.Utils

   Actual changes:
     * See the occ_n_br field of OneOcc.
     * postInlineUnconditionally

2. I found a small perf buglet in SetLevels; see the new
   function GHC.Core.Opt.SetLevels.hasFreeJoin

3. Remove the sc_cci field of StrictArg.  I found I could get
   its information from the sc_fun field instead.  Less to get
   wrong!

4. In ArgInfo, arrange that ai_dmds and ai_discs have a simpler
   invariant: they line up with the value arguments beyond ai_args
   This allowed a bit of nice refactoring; see isStrictArgInfo,
   lazyArgcontext, strictArgContext

There is virtually no difference in nofib. (The runtime numbers
are bogus -- I tried a few manually.)

        Program           Size    Allocs   Runtime   Elapsed  TotalMem
--------------------------------------------------------------------------------
            fft          +0.0%     -2.0%    -48.3%    -49.4%      0.0%
     multiplier          +0.0%     -2.2%    -50.3%    -50.9%      0.0%
--------------------------------------------------------------------------------
            Min          -0.4%     -2.2%    -59.2%    -60.4%      0.0%
            Max          +0.0%     +0.1%     +3.3%     +4.9%      0.0%
 Geometric Mean          +0.0%     -0.0%    -33.2%    -34.3%     -0.0%

Test T18282 is an existing example of these deeply-nested strict calls.
We get a big decrease in compile time (-85%) because so much less
inlining takes place.

Metric Decrease:
    T18282

- - - - -
6ee07b49 by Sylvain Henry at 2020-07-28T02:02:27-04:00
Bignum: add support for negative shifts (fix #18499)

shiftR/shiftL support negative arguments despite Haskell 2010 report
saying otherwise. We explicitly test for negative values which is bad
(it gets in the way of constant folding, etc.). Anyway, for consistency
we fix Bits instancesof Integer/Natural.

- - - - -
f305bbfd by Peter Trommler at 2020-07-28T02:03:02-04:00
config: Fix Haskell platform constructor w/ params

Fixes #18505

- - - - -
318bb17c by Oleg Grenrus at 2020-07-28T20:54:13-04:00
Fix typo in haddock

Spotted by `vilpan` on `#haskell`

- - - - -
39c89862 by Sergei Trofimovich at 2020-07-28T20:54:50-04:00
ghc/mk: don't build gmp packages for BIGNUM_BACKEND=native

Before this change make-based `BIGNUM_BACKEND=native` build was failing as:

```
x86_64-pc-linux-gnu-gcc: error: libraries/ghc-bignum/gmp/objs/*.o: No such file or directory
```

This happens because ghc.mk was pulling in gmp-dependent
ghc-bignum library unconditionally. The change avoid building
ghc-bignum.

Bug: https://gitlab.haskell.org/ghc/ghc/-/issues/18437
Signed-off-by: Sergei Trofimovich <slyfox at gentoo.org>

- - - - -
b9a880fc by Felix Wiemuth at 2020-07-29T15:06:35-04:00
Fix typo
- - - - -
c59064b0 by Brandon Chinn at 2020-07-29T15:07:11-04:00
Add regression test for #16341

- - - - -
a61411ca by Brandon Chinn at 2020-07-29T15:07:11-04:00
Pass dit_rep_tc_args to dsm_stock_gen_fn

- - - - -
a26498da by Brandon Chinn at 2020-07-29T15:07:11-04:00
Pass tc_args to gen_fn

- - - - -
44b11bad by Brandon Chinn at 2020-07-29T15:07:11-04:00
Filter out unreachable constructors when deriving stock instances (#16431)

- - - - -
bbc51916 by Simon Peyton Jones at 2020-07-29T15:07:47-04:00
Kill off sc_mult and as_mult fields

They are readily derivable from other fields, so this is more
efficient, and less error prone.

Fixes #18494

- - - - -
e3db4b4c by Peter Trommler at 2020-07-29T15:08:22-04:00
configure: Fix build system on ARM

- - - - -
96c31ea1 by Sylvain Henry at 2020-07-29T15:09:02-04:00
Fix bug in Natural multiplication (fix #18509)

A bug was lingering in Natural multiplication (inverting two limbs)
despite QuickCheck tests used during the development leading to wrong
results (independently of the selected backend).

- - - - -
e1dc3d7b by Krzysztof Gogolewski at 2020-07-29T15:09:39-04:00
Fix validation errors (#18510)

Test T2632 is a stage1 test that failed because of the Q => Quote change.

The remaining tests did not use quotation and failed when the path
contained a space.

- - - - -
6c68a842 by John Ericson at 2020-07-30T07:11:02-04:00
For `-fkeep-going` do not duplicate dependency edge code

We now compute the deps for `-fkeep-going` the same way that the
original graph calculates them, so the edges are correct. Upsweep really
ought to take the graph rather than a topological sort so we are never
recalculating anything, but at least things are recaluclated
consistently now.

- - - - -
502de556 by cgibbard at 2020-07-30T07:11:02-04:00
Add haddock comment for unfilteredEdges
and move the note about drop_hs_boot_nodes into it.
- - - - -
01c948eb by Ryan Scott at 2020-07-30T07:11:37-04:00
Clean up the inferred type variable restriction

This patch primarily:

* Documents `checkInferredVars` (previously called
  `check_inferred_vars`) more carefully. This is the
  function which throws an error message if a user quantifies an
  inferred type variable in a place where specificity cannot be
  observed. See `Note [Unobservably inferred type variables]` in
  `GHC.Rename.HsType`.

  Note that I now invoke `checkInferredVars` _alongside_
  `rnHsSigType`, `rnHsWcSigType`, etc. rather than doing so _inside_
  of these functions. This results in slightly more call sites for
  `checkInferredVars`, but it makes it much easier to enumerate the
  spots where the inferred type variable restriction comes into
  effect.
* Removes the inferred type variable restriction for default method
  type signatures, per the discussion in #18432. As a result, this
  patch fixes #18432.

Along the way, I performed some various cleanup:

* I moved `no_nested_foralls_contexts_err` into `GHC.Rename.Utils`
  (under the new name `noNestedForallsContextsErr`), since it now
  needs to be invoked from multiple modules. I also added a helper
  function `addNoNestedForallsContextsErr` that throws the error
  message after producing it, as this is a common idiom.
* In order to ensure that users cannot sneak inferred type variables
  into `SPECIALISE instance` pragmas by way of nested `forall`s, I
  now invoke `addNoNestedForallsContextsErr` when renaming
  `SPECIALISE instance` pragmas, much like when we rename normal
  instance declarations. (This probably should have originally been
  done as a part of the fix for #18240, but this task was somehow
  overlooked.) As a result, this patch fixes #18455 as a side effect.

- - - - -
d47324ce by Ryan Scott at 2020-07-30T07:12:16-04:00
Don't mark closed type family equations as occurrences

Previously, `rnFamInstEqn` would mark the name of the type/data
family used in an equation as an occurrence, regardless of what sort
of family it is. Most of the time, this is the correct thing to do.
The exception is closed type families, whose equations constitute its
definition and therefore should not be marked as occurrences.
Overzealously counting the equations of a closed type family as
occurrences can cause certain warnings to not be emitted, as observed
in #18470.  See `Note [Type family equations and occurrences]` in
`GHC.Rename.Module` for the full story.

This fixes #18470 with a little bit of extra-casing in
`rnFamInstEqn`. To accomplish this, I added an extra
`ClosedTyFamInfo` field to the `NonAssocTyFamEqn` constructor of
`AssocTyFamInfo` and refactored the relevant call sites accordingly
so that this information is propagated to `rnFamInstEqn`.

While I was in town, I moved `wrongTyFamName`, which checks that the
name of a closed type family matches the name in an equation for that
family, from the renamer to the typechecker to avoid the need for an
`ASSERT`. As an added bonus, this lets us simplify the details of
`ClosedTyFamInfo` a bit.

- - - - -
ebe2cf45 by Simon Peyton Jones at 2020-07-30T07:12:52-04:00
Remove an incorrect WARN in extendLocalRdrEnv

I noticed this warning going off, and discovered that it's
really fine.  This small patch removes the warning, and docments
what is going on.

- - - - -
9f71f697 by Simon Peyton Jones at 2020-07-30T07:13:27-04:00
Add two bangs to improve perf of flattening

This tiny patch improves the compile time of flatten-heavy
programs by 1-2%, by adding two bangs.

Addresses (somewhat) #18502

This reduces allocation by
   T9872b   -1.1%
   T9872d   -3.3%

   T5321Fun -0.2%
   T5631    -0.2%
   T5837    +0.1%
   T6048    +0.1%

Metric Decrease:
    T9872b
    T9872d

- - - - -
7c274cd5 by Sylvain Henry at 2020-07-30T22:54:48-04:00
Fix minimal imports dump for boot files (fix #18497)

- - - - -
175cb5b4 by Sylvain Henry at 2020-07-30T22:55:25-04:00
DynFlags: don't use sdocWithDynFlags in datacon ppr

We don't need to use `sdocWithDynFlags` to know whether we should
display linear types for datacon types, we already have
`sdocLinearTypes` field in `SDocContext`.  Moreover we want to remove
`sdocWithDynFlags` (#10143, #17957)).

- - - - -
380638a3 by Sylvain Henry at 2020-07-30T22:56:03-04:00
Bignum: fix powMod for gmp backend (#18515)

Also reenable integerPowMod test which had never been reenabled by
mistake.

- - - - -
56a7c193 by Sylvain Henry at 2020-07-31T19:32:09+02:00
Refactor CLabel pretty-printing

Pretty-printing CLabel relies on sdocWithDynFlags that we want to remove
(#10143, #17957). It uses it to query the backend and the platform.

This patch exposes Clabel ppr functions specialised for each backend so
that backend code can directly use them.

- - - - -
3b15dc3c by Sylvain Henry at 2020-07-31T19:32:09+02:00
DynFlags: don't use sdocWithDynFlags in GHC.CmmToAsm.Dwarf.Types

- - - - -
e30fed6c by Vladislav Zavialov at 2020-08-01T04:23:04-04:00
Test case for #17652

The issue was fixed by 19e80b9af252eee760dc047765a9930ef00067ec

- - - - -
22641742 by Ryan Scott at 2020-08-02T16:44:11-04:00
Remove ConDeclGADTPrefixPs

This removes the `ConDeclGADTPrefixPs` per the discussion in #18517.
Most of this patch simply removes code, although the code in the
`rnConDecl` case for `ConDeclGADTPrefixPs` had to be moved around a
bit:

* The nested `forall`s check now lives in the `rnConDecl` case for
  `ConDeclGADT`.
* The `LinearTypes`-specific code that used to live in the
  `rnConDecl` case for `ConDeclGADTPrefixPs` now lives in
  `GHC.Parser.PostProcess.mkGadtDecl`, which is now monadic so that
  it can check if `-XLinearTypes` is enabled.

Fixes #18157.

- - - - -
f2d1accf by Leon Schoorl at 2020-08-02T16:44:47-04:00
Fix GHC_STAGE definition generated by make

Fixes #18070

GHC_STAGE is the stage of the compiler we're building, it should be 1,2(,3?).
But make was generating 0 and 1.

Hadrian does this correctly using a similar `+ 1`:
https://gitlab.haskell.org/ghc/ghc/-/blob/eb8115a8c4cbc842b66798480fefc7ab64d31931/hadrian/src/Rules/Generate.hs#L245

- - - - -
947206f4 by Niklas Hambüchen at 2020-08-03T07:52:33+02:00
hadrian: Fix running stage0/bin/ghc with wrong package DB. Fixes #17468.

In the invocation of `cabal configure`, `--ghc-pkg-option=--global-package-db`
was already given correctly to tell `stage0/bin/ghc-pkg` that it should use
the package DB in `stage1/`.

However, `ghc` needs to be given this information as well, not only `ghc-pkg`!
Until now that was not the case; the package DB in `stage0` was given to
`ghc` instead.
This was wrong, because there is no binary compatibility guarantee that says
that the `stage0` DB's `package.cache` (which is written by the
stage0 == system-provided ghc-pkg) can be deserialised by the `ghc-pkg`
from the source code tree.

As a result, when trying to add fields to `InstalledPackageInfo` that get
serialised into / deserialised from the `package.cache`, errors like

    _build/stage0/lib/package.conf.d/package.cache: GHC.PackageDb.readPackageDb: inappropriate type (Not a valid Unicode code point!)

would appear. This was because the `stage0/bin/ghc would try to
deserialise the newly added fields from
`_build/stage0/lib/package.conf.d/package.cache`, but they were not in there
because the system `ghc-pkg` doesn't know about them and thus didn't write them
there.
It would try to do that because any GHC by default tries to read the global
package db in `../lib/package.conf.d/package.cache`.
For `stage0/bin/ghc` that *can never work* as explained above, so we
must disable this default via `-no-global-package-db` and give it the
correct package DB explicitly.

This is the same problem as #16534, and the same fix as in MR !780
(but in another context; that one was for developers trying out the
`stage0/bin/ghc` == `_build/ghc-stage1` interactively, while this fix
is for a `cabal configure` invocation).

I also noticed that the fix for #16534 forgot to pass `-no-global-package-db`,
and have fixed that in this commit as well.
It only worked until now because nobody tried to add a new ghc-pkg `.conf`
field since the introduction of Hadrian.

- - - - -
ef2ae81a by Alex Biehl at 2020-08-03T07:52:33+02:00
Hardcode RTS includes to cope with unregistered builds

- - - - -
d613ed76 by Sylvain Henry at 2020-08-05T03:59:27-04:00
Bignum: add backward compat integer-gmp functions

Also enhance bigNatCheck# and isValidNatural test

- - - - -
3f2f7718 by Sylvain Henry at 2020-08-05T03:59:27-04:00
Bignum: add more BigNat compat functions in integer-gmp

- - - - -
5e12cd17 by Krzysztof Gogolewski at 2020-08-05T04:00:04-04:00
Rename Core.Opt.Driver -> Core.Opt.Pipeline

Closes #18504.

- - - - -
2bff2f87 by Ben Gamari at 2020-08-05T04:00:39-04:00
Revert "iserv: Don't pass --export-dynamic on FreeBSD"

This reverts commit 2290eb02cf95e9cfffcb15fc9c593d5ef79c75d9.

- - - - -
53ce0db5 by Ben Gamari at 2020-08-05T04:00:39-04:00
Refactor handling of object merging

Previously to merge a set of object files we would invoke the linker as
usual, adding -r to the command-line. However, this can result in
non-sensical command-lines which causes lld to balk (#17962).

To avoid this we introduce a new tool setting into GHC, -pgmlm, which is
the linker which we use to merge object files.

- - - - -
eb7013c3 by Hécate at 2020-08-05T04:01:15-04:00
Remove all the unnecessary LANGUAGE pragmas

- - - - -
fbcb886d by Ryan Scott at 2020-08-05T04:01:51-04:00
Make CodeQ and TExpQ levity polymorphic

The patch is quite straightforward. The only tricky part is that
`Language.Haskell.TH.Lib.Internal` now must be `Trustworthy` instead
of `Safe` due to the `GHC.Exts` import (in order to import `TYPE`).

Since `CodeQ` has yet to appear in any released version of
`template-haskell`, I didn't bother mentioning the change to `CodeQ`
in the `template-haskell` release notes.

Fixes #18521.

- - - - -
686e06c5 by Vladislav Zavialov at 2020-08-06T13:34:05-04:00
Grammar for types and data/newtype constructors

Before this patch, we parsed types into a reversed sequence
of operators and operands. For example, (F x y + G a b * X)
would be parsed as [X, *, b, a, G, +, y, x, F],
using a simple grammar:

	tyapps
	  : tyapp
	  | tyapps tyapp

	tyapp
	  : atype
	  | PREFIX_AT atype
	  | tyop
	  | unpackedness

Then we used a hand-written state machine to assemble this
 either into a type,        using 'mergeOps',
     or into a constructor, using 'mergeDataCon'.

This is due to a syntactic ambiguity:

	data T1 a =          MkT1 a
	data T2 a = Ord a => MkT2 a

In T1, what follows after the = sign is a data/newtype constructor
declaration. However, in T2, what follows is a type (of kind
Constraint). We don't know which of the two we are parsing until we
encounter =>, and we cannot check for => without unlimited lookahead.

This poses a few issues when it comes to e.g. infix operators:

	data I1 = Int :+ Bool :+ Char          -- bad
	data I2 = Int :+ Bool :+ Char => MkI2  -- fine

By this issue alone we are forced into parsing into an intermediate
representation and doing a separate validation pass.

However, should that intermediate representation be as low-level as a
flat sequence of operators and operands?

Before GHC Proposal #229, the answer was Yes, due to some particularly
nasty corner cases:

	data T = ! A :+ ! B          -- used to be fine, hard to parse
	data T = ! A :+ ! B => MkT   -- bad

However, now the answer is No, as this corner case is gone:

	data T = ! A :+ ! B          -- bad
	data T = ! A :+ ! B => MkT   -- bad

This means we can write a proper grammar for types, overloading it in
the DisambECP style, see Note [Ambiguous syntactic categories].

With this patch, we introduce a new class, DisambTD. Just like
DisambECP is used to disambiguate between expressions, commands, and patterns,
DisambTD  is used to disambiguate between types and data/newtype constructors.

This way, we get a proper, declarative grammar for constructors and
types:

	infixtype
	  : ftype
	  | ftype tyop infixtype
	  | unpackedness infixtype

	ftype
	  : atype
	  | tyop
	  | ftype tyarg
	  | ftype PREFIX_AT tyarg

	tyarg
	  : atype
	  | unpackedness atype

And having a grammar for types means we are a step closer to using a
single grammar for types and expressions.

- - - - -
6770e199 by Vladislav Zavialov at 2020-08-06T13:34:05-04:00
Clean up the story around runPV/runECP_P/runECP_PV

This patch started as a small documentation change, an attempt to make
Note [Parser-Validator] and Note [Ambiguous syntactic categories]
more clear and up-to-date.

But it turned out that runECP_P/runECP_PV are weakly motivated,
and it's easier to remove them than to find a good rationale/explanation
for their existence.

As the result, there's a bit of refactoring in addition to
a documentation update.

- - - - -
826d07db by Vladislav Zavialov at 2020-08-06T13:34:06-04:00
Fix debug_ppr_ty ForAllTy (#18522)

Before this change, GHC would
pretty-print   forall k. forall a -> ()
          as   forall @k a. ()
which isn't even valid Haskell.

- - - - -
0ddb4384 by Vladislav Zavialov at 2020-08-06T13:34:06-04:00
Fix visible forall in ppr_ty (#18522)

Before this patch, this type:
  T :: forall k -> (k ~ k) => forall j -> k -> j -> Type
was printed incorrectly as:
  T :: forall k j -> (k ~ k) => k -> j -> Type

- - - - -
d2a43225 by Richard Eisenberg at 2020-08-06T13:34:06-04:00
Fail eagerly on a lev-poly datacon arg

Close #18534.

See commentary in the patch.

- - - - -
63348155 by Sylvain Henry at 2020-08-06T13:34:08-04:00
Use a type alias for Ways

- - - - -
9570c212 by Takenobu Tani at 2020-08-06T19:46:46-04:00
users-guide: Rename 8.12 to 9.0

GHC 8.12.1 has been renamed to GHC 9.0.1.

See also:
  https://mail.haskell.org/pipermail/ghc-devs/2020-July/019083.html

[skip ci]

- - - - -
3907ee01 by Cale Gibbard at 2020-08-07T08:34:46-04:00
A fix to an error message in monad comprehensions, and a move of dsHandleMonadicFailure
as suggested by comments on !2330.

- - - - -
fa9bb70a by Cale Gibbard at 2020-08-07T08:34:46-04:00
Add some tests for fail messages in do-expressions and monad-comprehensions.

- - - - -
5f036063 by Ben Gamari at 2020-08-07T08:35:21-04:00
cmm: Clean up Notes a bit

- - - - -
6402c124 by Ben Gamari at 2020-08-07T08:35:21-04:00
CmmLint: Check foreign call argument register invariant

As mentioned in Note [Register parameter passing] the arguments of
foreign calls cannot refer to caller-saved registers.

- - - - -
15b36de0 by Ben Gamari at 2020-08-07T08:35:21-04:00
nativeGen: One approach to fix #18527

Previously the code generator could produce corrupt C call sequences due
to register overlap between MachOp lowerings and the platform's calling
convention. We fix this using a hack described in Note [Evaluate C-call
arguments before placing in destination registers].

- - - - -
3847ae0c by Ben Gamari at 2020-08-07T08:35:21-04:00
testsuite: Add test for #18527

- - - - -
dd51d53b by Ben Gamari at 2020-08-07T08:35:21-04:00
testsuite: Fix prog001

Previously it failed as the `ghc` package was not visible.

- - - - -
e4f1b73a by Alan Zimmerman at 2020-08-07T23:58:10-04:00
ApiAnnotations; tweaks for ghc-exactprint update

Remove unused ApiAnns, add one for linear arrow.

Include API Annotations for trailing comma in export list.

- - - - -
8a665db6 by Ben Gamari at 2020-08-07T23:58:45-04:00
configure: Fix double-negation in ld merge-objects check

We want to only run the check if ld is gold.

Fixes the fix to #17962.
- - - - -
a11c9678 by Adam Sandberg Ericsson at 2020-08-09T11:32:25+02:00
hadrian: depend on boot compiler version #18001

- - - - -
c8873b52 by Alan Zimmerman at 2020-08-09T21:17:54-04:00
Api Annotations : Adjust SrcSpans for prefix bang (!).

And prefix ~

(cherry picked from commit 8dbee2c578b1f642d45561be3f416119863e01eb)

- - - - -
77398b67 by Sylvain Henry at 2020-08-09T21:18:34-04:00
Avoid allocations in `splitAtList` (#18535)

As suspected by @simonpj in #18535, avoiding allocations in
`GHC.Utils.Misc.splitAtList` when there are no leftover arguments is
beneficial for performance:

   On CI validate-x86_64-linux-deb9-hadrian:
    T12227 -7%
    T12545 -12.3%
    T5030  -10%
    T9872a -2%
    T9872b -2.1%
    T9872c -2.5%

Metric Decrease:
    T12227
    T12545
    T5030
    T9872a
    T9872b
    T9872c

- - - - -
8ba41a0f by Felix Yan at 2020-08-10T20:23:29-04:00
Correct a typo in ghc.mk
- - - - -
1c469264 by Felix Yan at 2020-08-10T20:23:29-04:00
Add a closing parenthesis too

- - - - -
acf537f9 by Sylvain Henry at 2020-08-10T20:24:09-04:00
Make splitAtList strict in its arguments

Also fix its slightly wrong comment

Metric Decrease:
    T5030
    T12227
    T12545

- - - - -
ab4d1589 by Ben Gamari at 2020-08-11T22:18:03-04:00
typecheck: Drop SPECIALISE pragmas when there is no unfolding

Previously the desugarer would instead fall over when it realized that
there was no unfolding for an imported function with a SPECIALISE
pragma. We now rather drop the SPECIALISE pragma and throw a warning.

Fixes #18118.

- - - - -
0ac8c0a5 by Ben Gamari at 2020-08-11T22:18:03-04:00
testsuite: Add test for #18118

- - - - -
c43078d7 by Sven Tennie at 2020-08-11T22:18:38-04:00
Add hie.yaml to ghc-heap

This enables IDE support by haskell-language-server for ghc-heap.

- - - - -
f1088b3f by Ben Gamari at 2020-08-11T22:19:15-04:00
testsuite: Specify metrics collected by T17516

Previously it collected everything, including "max bytes used". This is
problematic since the test makes no attempt to control for deviations in
GC timing, resulting in high variability. Fix this by only collecting
"bytes allocated".

- - - - -
accbc242 by Sylvain Henry at 2020-08-12T03:50:12-04:00
DynFlags: disentangle Outputable

- put panic related functions into GHC.Utils.Panic
- put trace related functions using DynFlags in GHC.Driver.Ppr

One step closer making Outputable fully independent of DynFlags.

Bump haddock submodule

- - - - -
db6dd810 by Ben Gamari at 2020-08-12T03:50:48-04:00
testsuite: Increase tolerance of T16916

T16916 (testing #16916) has been slightly fragile in CI due to its
reliance on CPU times. While it's hard to see how to eliminate
the time-dependence entirely, we can nevertheless make it more tolerant.

Fixes #16966.

- - - - -
bee43aca by Sylvain Henry at 2020-08-12T20:52:50-04:00
Rewrite and move the monad-state hack note

The note has been rewritten by @simonpj in !3851

[skip ci]

- - - - -
25fdf25e by Alan Zimmerman at 2020-08-12T20:53:26-04:00
ApiAnnotations: Fix parser for new GHC 9.0 features

- - - - -
7831fe05 by Ben Gamari at 2020-08-13T03:44:17-04:00
parser: Suggest ImportQualifiedPost in prepositive import warning

As suggested in #18545.

- - - - -
55dec4dc by Sebastian Graf at 2020-08-13T03:44:52-04:00
PmCheck: Better long-distance info for where bindings (#18533)

Where bindings can see evidence from the pattern match of the `GRHSs`
they belong to, but not from anything in any of the guards (which belong
to one of possibly many RHSs).

Before this patch, we did *not* consider said evidence, causing #18533,
where the lack of considering type information from a case pattern match
leads to failure to resolve the vanilla COMPLETE set of a data type.

Making available that information required a medium amount of
refactoring so that `checkMatches` can return a
`[(Deltas, NonEmpty Deltas)]`; one `(Deltas, NonEmpty Deltas)` for each
`GRHSs` of the match group. The first component of the pair is the
covered set of the pattern, the second component is one covered set per
RHS.

Fixes #18533.
Regression test case: T18533

- - - - -
cf97889a by Hécate at 2020-08-13T03:45:29-04:00
Re-add BangPatterns to CodePage.hs

- - - - -
ffc0d578 by Sylvain Henry at 2020-08-13T09:49:56-04:00
Add HomeUnit type

Since Backpack the "home unit" is much more involved than what it was
before (just an identifier obtained with `-this-unit-id`). Now it is
used in conjunction with `-component-id` and `-instantiated-with` to
configure module instantiations and to detect if we are type-checking an
indefinite unit or compiling a definite one.

This patch introduces a new HomeUnit datatype which is much easier to
understand. Moreover to make GHC support several packages in the same
instances, we will need to handle several HomeUnits so having a
dedicated (documented) type is helpful.

Finally in #14335 we will also need to handle the case where we have no
HomeUnit at all because we are only loading existing interfaces for
plugins which live in a different space compared to units used to
produce target code. Several functions will have to be refactored to
accept "Maybe HomeUnit" parameters instead of implicitly querying the
HomeUnit fields in DynFlags. Having a dedicated type will make this
easier.

Bump haddock submodule

- - - - -
8a51b2ab by Sylvain Henry at 2020-08-13T21:09:15-04:00
Make IOEnv monad one-shot (#18202)

On CI (x86_64-linux-deb9-hadrian, compile_time/bytes_allocated):

    T10421     -1.8%    (threshold: +/- 1%)
    T10421a    -1.7%    (threshold: +/- 1%)
    T12150     -4.9%    (threshold: +/- 2%)
    T12227     -1.6     (threshold: +/- 1%)
    T12425     -1.5%    (threshold: +/- 1%)
    T12545     -3.8%    (threshold: +/- 1%)
    T12707     -3.0%    (threshold: +/- 1%)
    T13035     -3.0%    (threshold: +/- 1%)
    T14683     -10.3%   (threshold: +/- 2%)
    T3064      -6.9%    (threshold: +/- 2%)
    T4801      -4.3%    (threshold: +/- 2%)
    T5030      -2.6%    (threshold: +/- 2%)
    T5321FD    -3.6%    (threshold: +/- 2%)
    T5321Fun   -4.6%    (threshold: +/- 2%)
    T5631      -19.7%   (threshold: +/- 2%)
    T5642      -13.0%   (threshold: +/- 2%)
    T783       -2.7     (threshold: +/- 2%)
    T9020      -11.1    (threshold: +/- 2%)
    T9961      -3.4%    (threshold: +/- 2%)

    T1969 (compile_time/bytes_allocated)  -2.2%  (threshold: +/-1%)
    T1969 (compile_time/max_bytes_used)   +24.4% (threshold: +/-20%)

Additionally on other CIs:

    haddock.Cabal                  -10.0%   (threshold: +/- 5%)
    haddock.compiler               -9.5%    (threshold: +/- 5%)
    haddock.base (max bytes used)  +24.6%   (threshold: +/- 15%)
    T10370 (max bytes used, i386)  +18.4%   (threshold: +/- 15%)

Metric Decrease:
    T10421
    T10421a
    T12150
    T12227
    T12425
    T12545
    T12707
    T13035
    T14683
    T3064
    T4801
    T5030
    T5321FD
    T5321Fun
    T5631
    T5642
    T783
    T9020
    T9961
    haddock.Cabal
    haddock.compiler
Metric Decrease 'compile_time/bytes allocated':
    T1969
Metric Increase 'compile_time/max_bytes_used':
    T1969
    T10370
    haddock.base

- - - - -
9f66fdf6 by Ben Gamari at 2020-08-14T15:50:34-04:00
testsuite: Drop --io-manager flag from testsuite configuration

This is no longer necessary as there are now dedicated testsuite ways
which run tests with WinIO.

- - - - -
55fd1dc5 by Ben Gamari at 2020-08-14T15:51:10-04:00
llvm-targets: Add i686 targets

Addresses #18422.

- - - - -
f4cc57fa by Ben Gamari at 2020-08-18T15:38:55-04:00
Allow unsaturated runRW# applications

Previously we had a very aggressive Core Lint check which caught
unsaturated applications of runRW#. However, there is nothing
wrong with such applications and they may naturally arise in desugared
Core. For instance, the desugared Core of Data.Primitive.Array.runArray#
from the `primitive` package contains:

    case ($) (runRW# @_ @_) (\s -> ...) of ...

In this case it's almost certain that ($) will be inlined, turning the
application into a saturated application. However, even if this weren't
the case there isn't a problem: CorePrep (after deleting an unnecessary
case) can simply generate code in its usual way, resulting in a call to
the Haskell definition of runRW#.

Fixes #18291.

- - - - -
3ac6ae7c by Ben Gamari at 2020-08-18T15:38:55-04:00
testsuite: Add test for #18291

- - - - -
a87a0b49 by Eli Schwartz at 2020-08-18T15:39:30-04:00
install: do not install sphinx doctrees

These files are 100% not needed at install time, and they contain
unreproducible info. See https://reproducible-builds.org/ for why this
matters.

- - - - -
194b25ee by Ben Gamari at 2020-08-18T15:40:05-04:00
testsuite: Allow baseline commit to be set explicitly

- - - - -
fdcf7645 by Ben Gamari at 2020-08-18T15:40:05-04:00
gitlab-ci: Use MR base commit as performance baseline

- - - - -
9ad5cab3 by Fendor at 2020-08-18T15:40:42-04:00
Expose UnitInfoMap as it is part of the public API

- - - - -
aa4b744d by Ben Gamari at 2020-08-18T22:11:36-04:00
testsuite: Only run llvm ways if llc is available

As noted in #18560, we previously would always run the LLVM ways since
`configure` would set `SettingsLlcCommand` to something non-null when
it otherwise couldn't find the `llc` executable. Now we rather probe for
the existence of the `llc` executable in the testsuite driver.

Fixes #18560.

- - - - -
0c5ed5c7 by Sylvain Henry at 2020-08-18T22:12:13-04:00
DynFlags: refactor GHC.CmmToAsm (#17957, #10143)

This patch removes the use of `sdocWithDynFlags` from GHC.CmmToAsm.*.Ppr

To do that I've had to make some refactoring:

* X86' and PPC's `Instr` are no longer `Outputable` as they require a
  `Platform` argument

* `Instruction` class now exposes `pprInstr :: Platform -> instr -> SDoc`

* as a consequence, I've refactored some modules to avoid .hs-boot files

* added (derived) functor instances for some datatypes parametric in the
  instruction type. It's useful for pretty-printing as we just have to
  map `pprInstr` before pretty-printing the container datatype.

- - - - -
731c8d3b by nineonine at 2020-08-19T18:47:39-04:00
Implement -Wredundant-bang-patterns (#17340)

Add new flag '-Wredundant-bang-patterns' that enables checks for "dead" bangs.
Dead bangs are the ones that under no circumstances can force a thunk that
wasn't already forced. Dead bangs are a form of redundant bangs. The new check
is performed in Pattern-Match Coverage Checker along with other checks (namely,
redundant and inaccessible RHSs). Given

    f :: Bool -> Int
    f True = 1
    f !x   = 2

we can detect dead bang patterns by checking whether @x ~ ⊥@ is satisfiable
where the PmBang appears in 'checkGrdTree'. If not, then clearly the bang is
dead. Such a dead bang is then indicated in the annotated pattern-match tree by
a 'RedundantSrcBang' wrapping. In 'redundantAndInaccessibles', we collect
all dead bangs to warn about.

Note that we don't want to warn for a dead bang that appears on a redundant
clause. That is because in that case, we recommend to delete the clause wholly,
including its leading pattern match.

Dead bang patterns are redundant. But there are bang patterns which are
redundant that aren't dead, for example

    f !() = 0

the bang still forces the match variable, before we attempt to match on (). But
it is redundant with the forcing done by the () match. We currently don't
detect redundant bangs that aren't dead.

- - - - -
eb9bdaef by Simon Peyton Jones at 2020-08-19T18:48:14-04:00
Add right-to-left rule for pattern bindings

Fix #18323 by adding a few lines of code to handle non-recursive
pattern bindings.  see GHC.Tc.Gen.Bind
Note [Special case for non-recursive pattern bindings]

Alas, this confused the pattern-match overlap checker; see #18323.

Note that this patch only affects pattern bindings like that
for (x,y) in this program

  combine :: (forall a . [a] -> a) -> [forall a. a -> a]
          -> ((forall a . [a] -> a), [forall a. a -> a])

  breaks = let (x,y) = combine head ids
           in x y True

We need ImpredicativeTypes for those [forall a. a->a] types to be
valid. And with ImpredicativeTypes the old, unprincipled "allow
unification variables to unify with a polytype" story actually
works quite well. So this test compiles fine (if delicatedly) with
old GHCs; but not with QuickLook unless we add this patch

- - - - -
293c7fba by Sylvain Henry at 2020-08-21T09:36:38-04:00
Put CFG weights into their own module (#17957)

It avoids having to query DynFlags to get them

- - - - -
50eb4460 by Sylvain Henry at 2020-08-21T09:36:38-04:00
Don't use DynFlags in CmmToAsm.BlockLayout (#17957)

- - - - -
659eb31b by Sylvain Henry at 2020-08-21T09:36:38-04:00
NCG: Dwarf configuration

* remove references to DynFlags in GHC.CmmToAsm.Dwarf
* add specific Dwarf options in NCGConfig instead of directly querying
  the debug level

- - - - -
2d8ca917 by Sylvain Henry at 2020-08-21T09:37:15-04:00
Fix -ddump-stg flag

-ddump-stg was dumping the initial STG (just after Core-to-STG pass)
which was misleading because we want the final STG to know if a function
allocates or not. Now we have a new flag -ddump-stg-from-core for this and
-ddump-stg is deprecated.

- - - - -
fddddbf4 by Vladislav Zavialov at 2020-08-21T09:37:49-04:00
Import qualified Prelude in Cmm/Parser.y

In preparation for the next version of 'happy', c95920 added a qualified
import to GHC/Parser.y but for some reason neglected GHC/Cmm/Parser.y

This patch adds the missing qualified import to GHC/Cmm/Parser.y and
also adds a clarifying comment to explain why this import is needed.

- - - - -
989c1c27 by Ben Gamari at 2020-08-21T11:27:53-04:00
gitlab-ci: Test master branch as well

While these builds are strictly speaking redundant (since every commit
is tested by @marge-bot before making it into `master`), they are nevertheless
useful as they are displayed in the branch's commit list in GitLab's web interface.

Fixes #18595.
- - - - -
e67ae884 by Aditya Gupta at 2020-08-22T03:29:00-04:00
mkUnique refactoring (#18362)

Move uniqFromMask from Unique.Supply to Unique.
Move the the functions that call mkUnique from Unique to Builtin.Uniques

- - - - -
03cfcfd4 by Wander Hillen at 2020-08-22T03:29:36-04:00
Add ubuntu 20.04 jobs for nightly and release

- - - - -
3f501545 by Craig Ferguson at 2020-08-22T03:30:13-04:00
Utils: clarify docs slightly

The previous comment implies `nTimes n f` is either `f^{n+1}` or
`f^{2^n}` (when in fact it's `f^n`).

- - - - -
8b865092 by Krzysztof Gogolewski at 2020-08-23T14:12:53+02:00
Do not print synonyms in :i (->), :i Type (#18594)

This adds a new printing flag `sdocPrintTypeAbbreviations` that is used
specifically to avoid ghci printing 'type (->) = (->)' and 'type Type = Type'.

- - - - -
d8f61182 by Krzysztof Gogolewski at 2020-08-23T14:12:56+02:00
Move pprTyTcApp' inside pprTyTcApp

No semantic change

- - - - -
364258e0 by Krzysztof Gogolewski at 2020-08-24T00:32:31-04:00
Fix types in silly shifts (#18589)

Patch written by Simon. I have only added a testcase.

- - - - -
b1eb38a0 by Sylvain Henry at 2020-08-24T00:33:13-04:00
Perf: make SDoc monad one-shot (#18202)

With validate-x86_64-linux-deb9-hadrian:
   T1969  -3.4% (threshold: +/-1%)
   T3294  -3.3% (threshold: +/-1%)
   T12707 -1.4% (threshold: +/-1%)

Additionally with validate-x86_64-linux-deb9-unreg-hadrian:
   T4801  -2.4% (threshold: +/-2%)
   T13035 -1.4% (threshold: +/-1%)
   T13379 -2.4% (threshold: +/-2%)
   ManyAlternatives -2.5% (threshold: +/-2%)
   ManyConstructors -3.0% (threshold: +/-2%)

Metric Decrease:
    T12707
    T1969
    T3294
    ManyAlternatives
    ManyConstructors
    T13035
    T13379
    T4801

- - - - -
a77b9ec2 by Krzysztof Gogolewski at 2020-08-24T10:04:20-04:00
Add a test for #18397

The bug was fixed by !3421.

- - - - -
05550a5a by Sylvain Henry at 2020-08-24T10:04:59-04:00
Avoid roundtrip through SDoc

As found by @monoidal on https://gitlab.haskell.org/ghc/ghc/-/merge_requests/3885#note_295126

- - - - -
0a1ecc5f by Ben Gamari at 2020-08-25T07:37:05-04:00
SysTools.Process: Handle exceptions in readCreateProcessWithExitCode'

In #18069 we are observing MVar deadlocks from somewhere in ghc.exe.
This use of MVar stood out as being one of the more likely culprits.
Here we make sure that it is exception-safe.

- - - - -
db8793ad by Richard Eisenberg at 2020-08-25T07:37:40-04:00
Use tcView, not coreView, in the pure unifier.

Addresses a lingering point within #11715.

- - - - -
fb77207a by Simon Peyton Jones at 2020-08-25T07:38:16-04:00
Use LIdP rather than (XRec p (IdP p))

This patch mainly just replaces use of
    XRec p (IdP p)
with
    LIdP p

One slightly more significant change is to parameterise
HsPatSynDetails over the pass rather than the argument type,
so that it's uniform with HsConDeclDetails and HsConPatDetails.

I also got rid of the dead code GHC.Hs.type.conDetailsArgs

But this is all just minor refactoring. No change in functionality.

- - - - -
8426a136 by Krzysztof Gogolewski at 2020-08-25T07:38:54-04:00
Add a test for #18585

- - - - -
2d635a50 by Takenobu Tani at 2020-08-26T04:50:21-04:00
linters: Make CPP linter skip image files

This patch adds an exclusion rule for `docs/users_guide/images`,
to avoid lint errors of PDF files.

- - - - -
b7d98cb2 by Takenobu Tani at 2020-08-26T04:50:21-04:00
users-guide: Color the logo on the front page of the PDF

This patch updates the logo with a recent color scheme.
This affects only the PDF version of the user's guide.

See also:
* https://mail.haskell.org/pipermail/ghc-devs/2020-August/019139.html
* https://gitlab.haskell.org/ghc/ghc/-/wikis/logo

- - - - -
0b17fa18 by Sylvain Henry at 2020-08-26T04:50:58-04:00
Refactor UnitId pretty-printing

When we pretty-print a UnitId for the user, we try to map it back to its
origin package name, version and component to print
"package-version:component" instead of some hash.

The UnitId type doesn't carry these information, so we have to look into
a UnitState to find them. This is why the Outputable instance of
UnitId used `sdocWithDynFlags` in order to access the `unitState` field
of DynFlags.

This is wrong for several reasons:

1. The DynFlags are accessed when the message is printed, not when it is
   generated. So we could imagine that the unitState may have changed
   in-between. Especially if we want to allow unit unloading.

2. We want GHC to support several independent sessions at once, hence
   several UnitState. The current approach supposes there is a unique
   UnitState as a UnitId doesn't indicate which UnitState to use.

See the Note [Pretty-printing UnitId] in GHC.Unit for the new approach
implemented by this patch.

One step closer to remove `sdocDynFlags` field from `SDocContext`
(#10143).

Fix #18124.

Also fix some Backpack code to use SDoc instead of String.

- - - - -
dc476a50 by Sylvain Henry at 2020-08-26T04:51:35-04:00
Bignum: fix BigNat subtraction (#18604)

There was a confusion between the boolean expected by
withNewWordArrayTrimedMaybe and the boolean returned by subtracting
functions.

- - - - -
fcb10b6c by Peter Trommler at 2020-08-26T10:42:30-04:00
PPC and X86: Portable printing of IEEE floats

GNU as and the AIX assembler support floating point literals.
SPARC seems to have support too but I cannot test on SPARC.
Curiously, `doubleToBytes` is also used in the LLVM backend.

To avoid endianness issues when cross-compiling float and double literals
are printed as C-style floating point values. The assembler then takes
care of memory layout and endianness.

This was brought up in #18431 by @hsyl20.

- - - - -
770100e0 by Krzysztof Gogolewski at 2020-08-26T10:43:13-04:00
primops: Remove Monadic and Dyadic categories

There were four categories of primops: Monadic, Dyadic, Compare, GenPrimOp.

The compiler does not treat Monadic and Dyadic in any special way,
we can just replace them with GenPrimOp.

Compare is still used in isComparisonPrimOp.

- - - - -
01ff8c89 by Aditya Gupta at 2020-08-27T14:19:26-04:00
Consolidate imports in getMinimalImports (#18264)

- - - - -
bacccb73 by Ryan Scott at 2020-08-27T14:20:01-04:00
Make {hsExpr,hsType,pat}NeedsParens aware of boxed 1-tuples

`hsExprNeedsParens`, `hsTypeNeedsParens`, and `patNeedsParens`
previously assumed that all uses of explicit tuples in the source
syntax never need to be parenthesized. This is true save for one
exception: boxed one-tuples, which use the `Solo` data type from
`GHC.Tuple` instead of special tuple syntax. This patch adds the
necessary logic to the three `*NeedsParens` functions to handle
`Solo` correctly.

Fixes #18612.

- - - - -
c6f50cea by Krzysztof Gogolewski at 2020-08-28T02:22:36-04:00
Add missing primop documentation (#18454)

- Add three pseudoops to primops.txt.pp, so that Haddock renders
  the documentation
- Update comments
- Remove special case for "->" - it's no longer exported from GHC.Prim
- Remove reference to Note [Compiling GHC.Prim] - the ad-hoc fix is no
  longer there after updates to levity polymorphism.
- Document GHC.Prim
- Remove the comment that lazy is levity-polymorphic.
  As far as I can tell, it never was: in 80e399639,
  only the unfolding was given an open type variable.
- Remove haddock hack in GHC.Magic - no longer neccessary after
  adding realWorld# to primops.txt.pp.

- - - - -
f065b6b0 by Tamar Christina at 2020-08-28T02:23:13-04:00
Fix use distro toolchian

- - - - -
4517a382 by Tamar Christina at 2020-08-28T02:23:13-04:00
document how build system find toolchains on Windows

- - - - -
329f7cb9 by Ben Gamari at 2020-08-31T22:59:14-04:00
base: Better error message on invalid getSystemTimerManager call

Previously we would produce a rather unhelpful pattern match failure
error in the case where the user called `getSystemTimerManager` in a
program which isn't built with `-threaded`. This understandably confused
the user in #15616.

Fixes #15616.

- - - - -
f6d70a8f by Roland Senn at 2020-08-31T22:59:50-04:00
Add tests for #15617.

Avoid a similar regression in the future.

- - - - -
e5969fd0 by Roland Senn at 2020-08-31T23:00:27-04:00
Add additional tests for #18172 (Followup MR 3543)

There was still one active discussion [thread](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/3543#note_284325) when MR !3543 got merged.

This MR adds the requested tests exercising the changes in
`compiler/GHC/HsToCore/Match/Literal.hs:warnAboutEmptyEnumerations` and its sub-functions.

- - - - -
fe18b482 by Ben Gamari at 2020-08-31T23:01:02-04:00
Bump Win32 and process submodules

- - - - -
2da93308 by Sylvain Henry at 2020-08-31T23:01:39-04:00
Hadrian: fix slow-validate flavour (#18586)

- - - - -
85e13008 by Andreas Klebinger at 2020-08-31T23:02:15-04:00
Update dominator code with fixes from the dom-lt package.

Two bugs turned out in the package that have been fixed since.
This MR includes this fixes in the GHC port of the code.

- - - - -
dffb38fa by Andreas Klebinger at 2020-08-31T23:02:15-04:00
Dominators.hs: Use unix line endings

- - - - -
6189cc04 by Moritz Angermann at 2020-08-31T23:02:50-04:00
[fixup 3433] move debugBelch into IF_DEBUG(linker)

The commit in dff1cb3d9c111808fec60190747272b973547c52 incorrectly left
the `debugBelch` function without a comment or IF_DEBUG(linker,)
decoration. This rectifies it.

Needs at least a 8.10 backport, as it was backported in 6471cc6aff80d5deebbdb1bf7b677b31ed2af3d5

- - - - -
bcb68a3f by Sylvain Henry at 2020-08-31T23:03:27-04:00
Don't store HomeUnit in UnitConfig

Allow the creation of a UnitConfig (hence of a UnitState) without having
a HomeUnit. It's required for #14335.

- - - - -
0a372387 by Sylvain Henry at 2020-08-31T23:04:04-04:00
Fix documentation and fix "check" bignum backend (#18604)

- - - - -
eb85f125 by Moritz Angermann at 2020-08-31T23:04:39-04:00
Set the dynamic-system-linker flag to Manual

This flag should be user controllable, hence Manual: True.

- - - - -
380ef845 by Sven Tennie at 2020-08-31T23:05:14-04:00
Ignore more files

Ignore files from "new style" cabal builds (dist-newstyle folders) and
from clangd (C language server).

- - - - -
74a7fbff by Takenobu Tani at 2020-08-31T23:05:51-04:00
Limit upper version of Happy for ghc-9.0 and earlier (#18620)

This patch adds the upper bound of a happy version for ghc-9.0
and earlier.

Currently, we can't use happy-1.20.0 for ghc-9.0.

See #18620.

- - - - -
a4473f02 by Takenobu Tani at 2020-08-31T23:05:51-04:00
Limit upper version of Happy for ghc-9.2 (#18620)

This patch adds the upper bound of a happy version for ghc-9.2.

Currently, We can use happy-1.19 or happy-1.20 for ghc-9.2.

See #18620.

- - - - -
a8a2568b by Sylvain Henry at 2020-08-31T23:06:28-04:00
Bignum: add BigNat compat functions (#18613)

- - - - -
884245dd by Sylvain Henry at 2020-09-01T12:39:36-04:00
Fix FastString lexicographic ordering (fix #18562)

- - - - -
4b4fbc58 by Sylvain Henry at 2020-09-01T12:39:36-04:00
Remove "Ord FastString" instance

FastStrings can be compared in 2 ways: by Unique or lexically. We don't
want to bless one particular way with an "Ord" instance because it leads
to bugs (#18562) or to suboptimal code (e.g. using lexical comparison
while a Unique comparison would suffice).

UTF-8 encoding has the advantage that sorting strings by their encoded
bytes also sorts them by their Unicode code points, without having to
decode the actual code points. BUT GHC uses Modified UTF-8 which
diverges from UTF-8 by encoding \0 as 0xC080 instead of 0x00 (to avoid
null bytes in the middle of a String so that the string can still be
null-terminated). This patch adds a new `utf8CompareShortByteString`
function that performs sorting by bytes but that also takes Modified
UTF-8 into account. It is much more performant than decoding the strings
into [Char] to perform comparisons (which we did in the previous patch).

Bump haddock submodule

- - - - -
b4edcde7 by Ben Gamari at 2020-09-01T14:53:42-04:00
testsuite: Add broken test for #18302

- - - - -
bfab2a30 by Sebastian Graf at 2020-09-02T15:54:55-04:00
Turn on -XMonoLocalBinds by default (#18430)

And fix the resulting type errors.

Co-authored-by: Krzysztof Gogolewski <krz.gogolewski at gmail.com>

Metric Decrease:
    parsing001

- - - - -
c30cc0e9 by David Feuer at 2020-09-02T15:55:31-04:00
Remove potential space leak from Data.List.transpose

Previously, `transpose` produced a list of heads
and a list of tails independently. This meant that
a function using only some heads, and only some tails,
could potentially leak space. Use `unzip` to work
around the problem by producing pairs and selector
thunks instead. Time and allocation behavior will
be worse, but there should be no more leak potential.
- - - - -
ffc3da47 by Sylvain Henry at 2020-09-02T15:56:11-04:00
Remove outdated note

- - - - -
85e62123 by Sylvain Henry at 2020-09-02T15:56:48-04:00
Bignum: add missing compat import/export functions

- - - - -
397c2b03 by Ben Gamari at 2020-09-03T17:31:47-04:00
configure: Work around Raspbian's silly packaging decisions

See #17856.

- - - - -
4891c18a by Kathryn Spiers at 2020-09-03T17:32:24-04:00
expected-undocumented-flags remove kill flags

It looks like the flags were removed in https://gitlab.haskell.org/ghc/ghc/-/commit/3e27205a66b06a4501d87eb31e285eadbc693eb7
and can safely be removed here
- - - - -
1d6d6488 by Sylvain Henry at 2020-09-04T16:24:20-04:00
Don't rely on CLabel's Outputable instance in CmmToC

This is in preparation of the removal of sdocWithDynFlags (#10143),
hence of the refactoring of CLabel's Outputable instance.

- - - - -
89ce7cdf by Sylvain Henry at 2020-09-04T16:24:59-04:00
DynFlags: use Platform in foldRegs*

- - - - -
220ad8d6 by Sylvain Henry at 2020-09-04T16:24:59-04:00
DynFlags: don't pass DynFlags to cmmImplementSwitchPlans

- - - - -
c1e54439 by Ryan Scott at 2020-09-04T16:25:35-04:00
Introduce isBoxedTupleDataCon and use it to fix #18644

The code that converts promoted tuple data constructors to
`IfaceType`s in `GHC.CoreToIface` was using `isTupleDataCon`, which
conflates boxed and unboxed tuple data constructors. To avoid this,
this patch introduces `isBoxedTupleDataCon`, which is like
`isTupleDataCon` but only works for _boxed_ tuple data constructors.

While I was in town, I was horribly confused by the fact that there
were separate functions named `isUnboxedTupleCon` and
`isUnboxedTupleTyCon` (similarly, `isUnboxedSumCon` and
`isUnboxedSumTyCon`). It turns out that the former only works for
data constructors, despite its very general name! I opted to rename
`isUnboxedTupleCon` to `isUnboxedTupleDataCon` (similarly, I renamed
`isUnboxedSumCon` to `isUnboxedSumDataCon`) to avoid this potential
confusion, as well as to be more consistent with
the naming convention I used for `isBoxedTupleDataCon`.

Fixes #18644.

- - - - -
07bdcac3 by GHC GitLab CI at 2020-09-04T22:26:25-04:00
configure: Avoid hard-coded ld path on Windows

The fix to #17962 ended up regressing on Windows as it failed to
replicate the logic responsible for overriding the toolchain paths on
Windows. This resulted in a hard-coded path to a directory that likely
doesn't exist on the user's system (#18550).

- - - - -
0be8e746 by Benjamin Maurer at 2020-09-04T22:27:01-04:00
Documented the as of yet undocumented '--print-*'  GHC flags,
as well as `-split-objs`, since that is related to
`--print-object-splitting-supported`.
See #18641

- - - - -
4813486f by Sylvain Henry at 2020-09-04T22:27:44-04:00
Move Hadrian's wiki pages in tree (fix #16165)

Only the debugging page contains interesting stuff. Some of this stuff
looks old (e.g. recommending "cabal install")...

- - - - -
7980ae23 by GHC GitLab CI at 2020-09-05T14:50:52-04:00
rts: Consistently use stgMallocBytes instead of malloc

This can help in debugging RTS memory leaks since all allocations go
through the same interface.

- - - - -
67059893 by Ben Gamari at 2020-09-05T14:51:27-04:00
configure: Fix whitespace

- - - - -
be2cc0ad by Ben Gamari at 2020-09-05T14:51:27-04:00
gitlab-ci: More intelligent detection of locale availability

Previously ci.sh would unconditionally use C.UTF-8. However, this fails
on Centos 7, which appears not to provide this locale. Now we first try
C.UTF-8, then try en_US.UTF-8, then fail.

Works around #18607.

- - - - -
15dca847 by Ben Gamari at 2020-09-05T14:51:27-04:00
gitlab-ci: Rename RELEASE variable to RELEASE_JOB

This interfered with the autoconf variable of the same name, breaking
pre-release builds.

- - - - -
bec0d170 by Ben Gamari at 2020-09-05T14:51:27-04:00
gitlab-ci: Bump Windows toolchain version

This should have been done when we bumped the bootstrap compiler to
8.8.4.

- - - - -
9fbaee21 by Ben Gamari at 2020-09-05T14:51:27-04:00
gitlab-ci: Drop Windows make job

These are a significant burden on our CI resources and end up failing
quite often due to #18274. Here I drop the make jobs during
validaion; it is now run only during the nightly builds.

- - - - -
869f6e19 by Ben Gamari at 2020-09-05T14:51:27-04:00
testsuite: Drop Windows-specific output for parseTree

The normalise_slashes normaliser should handle this.

- - - - -
2c9f743c by Ben Gamari at 2020-09-05T14:51:28-04:00
testsuite: Mark T5975[ab] as broken on Windows

Due to #7305.

- - - - -
643785e3 by Ben Gamari at 2020-09-05T14:51:28-04:00
gitlab-ci: Fix typo

A small typo in a rule regular expression.

- - - - -
c5413fc6 by Wander Hillen at 2020-09-07T09:33:54-04:00
Add clarification regarding poll/kqueue flags

- - - - -
10434d60 by Ben Gamari at 2020-09-07T09:34:32-04:00
gitlab-ci: Configure bignum backend in Hadrian builds

- - - - -
d4bc9f0d by Ben Gamari at 2020-09-07T09:34:32-04:00
gitlab-ci: Use hadrian builds for Windows release artifacts

- - - - -
4ff93292 by Moritz Angermann at 2020-09-07T21:18:39-04:00
[macOS] improved runpath handling

In b592bd98ff25730bbe3c13d6f62a427df8c78e28 we started using
-dead_strip_dylib on macOS when lining dynamic libraries and binaries.
The underlying reason being the Load Command Size Limit in macOS
Sierra (10.14) and later.

GHC will produce @rpath/libHS... dependency entries together with a
corresponding RPATH entry pointing to the location of the libHS...
library. Thus for every library we produce two Load Commands.  One to
specify the dependent library, and one with the path where to find it.
This makes relocating libraries and binaries easier, as we just need to
update the RPATH entry with the install_name_tool. The dynamic linker
will then subsitute each @rpath with the RPATH entries it finds in the
libraries load commands or the environement, when looking up @rpath
relative libraries.

-dead_strip_dylibs intructs the linker to drop unused libraries. This in
turn help us reduce the number of referenced libraries, and subsequently
the size of the load commands.  This however does not remove the RPATH
entries.  Subsequently we can end up (in extreme cases) with only a
single @rpath/libHS... entry, but 100s or more RPATH entries in the Load
Commands.

This patch rectifies this (slighly unorthodox) by passing *no* -rpath
arguments to the linker at link time, but -headerpad 8000.  The
headerpad argument is in hexadecimal and the maxium 32k of the load
command size.  This tells the linker to pad the load command section
enough for us to inject the RPATHs later.  We then proceed to link the
library or binary with -dead_strip_dylibs, and *after* the linking
inspect the library to find the left over (non-dead-stripped)
dependencies (using otool).  We find the corresponding RPATHs for each
@rpath relative dependency, and inject them into the library or binary
using the install_name_tool.  Thus achieving a deadstripped dylib (and
rpaths) build product.

We can not do this in GHC, without starting to reimplement a dynamic
linker as we do not know which symbols and subsequently libraries are
necessary.

Commissioned-by: Mercury Technologies, Inc. (mercury.com)

- - - - -
df04b81e by Sylvain Henry at 2020-09-07T21:19:20-04:00
Move DynFlags test into updateModDetailsIdInfos's caller (#17957)

- - - - -
ea1cbb8f by Ben Gamari at 2020-09-08T15:42:02-04:00
rts: Add stg_copyArray_barrier to RtsSymbols list

It's incredible that this wasn't noticed until now.

- - - - -
d7b2f799 by Daishi Nakajima at 2020-09-08T15:42:41-04:00
testsuite: Output performance test results in tabular format
this was suggested in #18417.

Change the print format of the values.
* Shorten commit hash
* Reduce precision of the "Value" field
* Shorten metrics name
  * e.g. runtime/bytes allocated -> run/alloc
* Shorten "MetricsChange"
  * e.g. unchanged -> unch, increased -> incr

And, print the baseline environment if there are baselines that were
measured in a different environment than the current environment.

If all "Baseline commit" are the same, print it once.

- - - - -
44472daf by Ryan Scott at 2020-09-08T15:43:16-04:00
Make the forall-or-nothing rule only apply to invisible foralls (#18660)

This fixes #18660 by changing `isLHsForAllTy` to
`isLHsInvisForAllTy`, which is sufficient to make the
`forall`-or-nothing rule only apply to invisible `forall`s. I also
updated some related documentation and Notes while I was in the
neighborhood.

- - - - -
0c61cbff by Ben Gamari at 2020-09-08T15:43:54-04:00
gitlab-ci: Handle distributions without locales

Previously we would assume that the `locale` utility exists. However,
this is not so on Alpine as musl's locale support is essentially
non-existent.

(cherry picked from commit 17cdb7ac3b557a245fee1686e066f9f770ddc21e)

- - - - -
d989c842 by Ben Gamari at 2020-09-08T15:43:55-04:00
gitlab-ci: Accept Centos 7 C.utf8 locale

Centos apparently has C.utf8 rather than C.UTF-8.

(cherry picked from commit d9f85dd25a26a04d3485470afb3395ee2dec6464)

- - - - -
e5a2899c by John Ericson at 2020-09-09T00:46:05-04:00
Use "to" instead of "2" in internal names of conversion ops

Change the constructors for the primop union, and also names of the
literal conversion functions.

"2" runs into trouble when we need to do conversions from fixed-width
types, and end up with thing like "Int642Word".

Only the names internal to GHC are changed, as I don't want to worry
about breaking changes ATM.

- - - - -
822f1057 by Ryan Scott at 2020-09-09T00:46:41-04:00
Postpone associated tyfam default checks until after typechecking

Previously, associated type family defaults were validity-checked
during typechecking. Unfortunately, the error messages that these
checks produce run the risk of printing knot-tied type constructors,
which will cause GHC to diverge. In order to preserve the current
error message's descriptiveness, this patch postpones these validity
checks until after typechecking, which are now located in the new
function `GHC.Tc.Validity.checkValidAssocTyFamDeflt`.

Fixes #18648.

- - - - -
8c892689 by Sylvain Henry at 2020-09-09T11:19:24-04:00
DynFlags: add OptCoercionOpts

Use OptCoercionOpts to avoid threading DynFlags all the way down to
GHC.Core.Coercion.Opt

- - - - -
3f32a9c0 by Sylvain Henry at 2020-09-09T11:19:24-04:00
DynFlags: add UnfoldingOpts and SimpleOpts

Milestone: after this patch, we only use 'unsafeGlobalDynFlags' for the
state hack and for debug in Outputable.

- - - - -
b3df72a6 by Sylvain Henry at 2020-09-09T11:19:24-04:00
DynFlags: add sm_pre_inline field into SimplMode (#17957)

It avoids passing and querying DynFlags down in the simplifier.

- - - - -
ffae5792 by Sylvain Henry at 2020-09-09T11:19:24-04:00
Add comments about sm_dflags and simpleOptExpr

- - - - -
7911d0d9 by Alan Zimmerman at 2020-09-09T11:20:03-04:00
Remove GENERATED pragma, as it is not being used

@alanz pointed out on ghc-devs that the payload of this pragma does
not appear to be used anywhere.

I (@bgamari) did some digging and traced the pragma's addition back to
d386e0d2 (way back in 2006!).

It appears that it was intended to be used by code generators for use
in informing the code coveraging checker about generated code
provenance. When it was added it used the pragma's "payload" fields as
source location information to build an "ExternalBox". However, it
looks like this was dropped a year later in 55a5d8d9.  At this point
it seems like the pragma serves no useful purpose.

Given that it also is not documented, I think we should remove it.

Updates haddock submodule

Closes #18639

- - - - -
5aae5b32 by Ben Gamari at 2020-09-09T18:31:40-04:00
gitlab-ci: Bump Docker images

We now generate our Docker images via Dhall definitions, as described in
ghc/ci-images!52. Additionally, we are far more careful about where tools
come from, using the ALEX, HAPPY, HSCOLOR, and GHC environment variables
(set in the Dockerfiles) to find bootstrapping tools.

- - - - -
4ce9fe88 by Ben Gamari at 2020-09-09T18:31:40-04:00
hadrian: Fix leakage of GHC in PATH into build

Previously hadrian would use GHC on PATH when configuring packages (or
fail if there is no such GHC). Fix this. Unfortunately this runs into
another bug in Cabal which we workaround.

- - - - -
291a15dd by Ben Gamari at 2020-09-09T18:31:40-04:00
utils: Bump cabal-version of hp2ps and unlit

- - - - -
4798caa0 by David Himmelstrup at 2020-09-09T18:32:16-04:00
rts comment: RTS_TICKY_SYMBOLS moved from rts/Linker.c to rts/RtsSymbols.c

- - - - -
67ce72da by Sebastian Graf at 2020-09-10T10:35:33-04:00
Add long-distance info for pattern bindings (#18572)

We didn't consider the RHS of a pattern-binding before, which led to
surprising warnings listed in #18572.

As can be seen from the regression test T18572, we get the expected
output now.

- - - - -
1207576a by Sebastian Graf at 2020-09-10T10:35:33-04:00
PmCheck: Big refactor using guard tree variants more closely following source syntax (#18565)

Previously, we desugared and coverage checked plain guard trees as
described in Lower Your Guards. That caused (in !3849) quite a bit of
pain when we need to partially recover tree structure of the input
syntax to return covered sets for long-distance information, for
example.

In this refactor, I introduced a guard tree variant for each relevant
source syntax component of a pattern-match (mainly match groups, match,
GRHS, empty case, pattern binding). I made sure to share as much
coverage checking code as possible, so that the syntax-specific checking
functions are just wrappers around the more substantial checking
functions for the LYG primitives (`checkSequence`, `checkGrds`).

The refactoring payed off in clearer code and elimination of all panics
related to assumed guard tree structure and thus fixes #18565.

I also took the liberty to rename and re-arrange the order of functions
and comments in the module, deleted some dead and irrelevant Notes,
wrote some new ones and gave an overview module haddock.

- - - - -
95455982 by GHC GitLab CI at 2020-09-10T10:36:09-04:00
hadrian: Don't include -fdiagnostics-color in argument hash

Otherwise the input hash will vary with whether colors are requested,
which changed with `isatty`.

Fixes #18672.

- - - - -
6abe4a1c by Sebastian Graf at 2020-09-10T17:02:00+02:00
.gitignore *.hiedb files

- - - - -
3777be14 by Sebastian Graf at 2020-09-10T17:03:12+02:00
PmCheck: Handle ⊥ and strict fields correctly (#18341)

In #18341, we discovered an incorrect digression from Lower Your Guards.
This MR changes what's necessary to support properly fixing #18341.

In particular, bottomness constraints are now properly tracked in the
oracle/inhabitation testing, as an additional field
`vi_bot :: Maybe Bool` in `VarInfo`. That in turn allows us to
model newtypes as advertised in the Appendix of LYG and fix #17725.
Proper handling of ⊥ also fixes #17977 (once again) and fixes #18670.

For some reason I couldn't follow, this also fixes #18273.

I also added a couple of regression tests that were missing. Most of
them were already fixed before.

In summary, this patch fixes #18341, #17725, #18273, #17977 and #18670.

Metric Decrease:
    T12227

- - - - -
1bd28931 by David Himmelstrup at 2020-09-11T09:59:43-04:00
Define TICKY_TICKY when compiling cmm RTS files.

- - - - -
15e67801 by David Himmelstrup at 2020-09-11T09:59:43-04:00
Fix typos in TICKY_TICKY symbol names.

- - - - -
8a5a91cb by David Himmelstrup at 2020-09-11T09:59:43-04:00
Enable TICKY_TICKY for debug builds when building with makefiles.

- - - - -
fc965c09 by Sandy Maguire at 2020-09-12T00:31:36-04:00
Add clamp function to Data.Ord

- - - - -
fb6e29e8 by Sandy Maguire at 2020-09-12T00:31:37-04:00
Add tests

- - - - -
2a942285 by Sebastian Graf at 2020-09-12T00:32:13-04:00
PmCheck: Disattach COMPLETE pragma lookup from TyCons

By not attaching COMPLETE pragmas with a particular TyCon and instead
assume that every COMPLETE pragma is applicable everywhere, we can
drastically simplify the logic that tries to initialise available
COMPLETE sets of a variable during the pattern-match checking process,
as well as fixing a few bugs.

Of course, we have to make sure not to report any of the
ill-typed/unrelated COMPLETE sets, which came up in a few regression
tests.

In doing so, we fix #17207, #18277 and #14422.

There was a metric decrease in #18478 by ~20%.

Metric Decrease:
    T18478

- - - - -
389a6683 by Ben Gamari at 2020-09-12T00:32:49-04:00
hadrian: Pass input file to makeindex

Strangely I find that on Alpine (and apparently only on Alpine) the
latex makeindex command expects to be given a filename, lest it reads
from stdin.

- - - - -
853d121a by Ryan Scott at 2020-09-12T00:33:25-04:00
Don't quote argument to Hadrian's test-env flag (#18656)

Doing so causes the name of the test environment to gain an extra
set of double quotes, which changes the name entirely.

Fixes #18656.

- - - - -
8440b5fa by Krzysztof Gogolewski at 2020-09-12T00:33:25-04:00
Make sure we can read past perf notes

See #18656.

- - - - -
2157be52 by theobat at 2020-09-12T21:27:04-04:00
Avoid iterating twice in `zipTyEnv` (#18535)

zipToUFM is a new function to replace `listToUFM (zipEqual ks vs)`.
An explicit recursion is preferred due to the sensible nature of fusion.

    T12227 -6.0%
    T12545 -12.3%
    T5030  -9.0%
    T9872a -1.6%
    T9872b -1.6%
    T9872c -2.0%

 -------------------------
Metric Decrease:
    T12227
    T12545
    T5030
    T9872a
    T9872b
    T9872c
-------------------------

- - - - -
69ea2fee by Sebastian Graf at 2020-09-12T21:27:40-04:00
Make `tcCheckSatisfiability` incremental (#18645)

By taking and returning an `InertSet`.
Every new `TcS` session can then pick up where a prior session left with
`setTcSInerts`.

Since we don't want to unflatten the Givens (and because it leads to
infinite loops, see !3971), we introduced a new variant of `runTcS`,
`runTcSInerts`, that takes and returns the `InertSet` and makes
sure not to unflatten the Givens after running the `TcS` action.

Fixes #18645 and #17836.

Metric Decrease:
    T17977
    T18478

- - - - -
a77e48d2 by Sebastian Graf at 2020-09-12T21:27:40-04:00
Extract definition of DsM into GHC.HsToCore.Types

`DsM` was previously defined in `GHC.Tc.Types`, along with `TcM`. But
`GHC.Tc.Types` is in the set of transitive dependencies of `GHC.Parser`,
a set which we aim to minimise. Test case `CountParserDeps` checks for
that.

Having `DsM` in that set means the parser also depends on the innards of
the pattern-match checker in `GHC.HsToCore.PmCheck.Types`, which is the
reason we have that module in the first place.

In the previous commit, we represented the `TyState` by an `InertSet`,
but that pulls the constraint solver as well as 250 more modules into
the set of dependencies, triggering failure of `CountParserDeps`.
Clearly, we want to evolve the pattern-match checker (and the desugarer)
without being concerned by this test, so this patch includes a small
refactor that puts `DsM` into its own module.

- - - - -
fd5d622a by Sebastian Graf at 2020-09-12T21:27:40-04:00
Hackily decouple the parser from the desugarer

In a hopefully temporary hack, I re-used the idea from !1957 of using a
nullary type family to break the dependency from GHC.Driver.Hooks on the
definition of DsM ("Abstract Data").
This in turn broke the last dependency from the parser to the desugarer.
More details in `Note [The Decoupling Abstract Data Hack]`.

In the future, we hope to undo this hack again in favour of breaking the
dependency from the parser to DynFlags altogether.

- - - - -
35a7b7ec by Adam Sandberg Eriksson at 2020-09-14T17:46:16-04:00
docs: -B rts option sounds the bell on every GC (#18351)
- - - - -
5ae8212c by Wander Hillen at 2020-09-14T17:46:54-04:00
Populate gitlab cache after building

- - - - -
a5ffb39a by Wander Hillen at 2020-09-14T17:46:54-04:00
Move ahead cabal cache restoration to before use of cabal

- - - - -
e8b37c21 by Wander Hillen at 2020-09-14T17:46:54-04:00
Do the hadrian rebuild multicore

- - - - -
07762eb5 by Wander Hillen at 2020-09-14T17:46:54-04:00
Also cache other hadrian builds

- - - - -
8610bcbe by DenisFrezzato at 2020-09-15T15:19:08-04:00
Fix rtsopts documentation

- - - - -
c7182a5c by Simon Peyton Jones at 2020-09-15T15:19:44-04:00
Care with implicit-parameter superclasses

Two bugs, #18627 and #18649, had the same cause: we were not
account for the fact that a constaint tuple might hide an implicit
parameter.

The solution is not hard: look for implicit parameters in
superclasses.  See Note [Local implicit parameters] in
GHC.Core.Predicate.

Then we use this new function in two places

* The "short-cut solver" in GHC.Tc.Solver.Interact.shortCutSolver
  which simply didn't handle implicit parameters properly at all.
  This fixes #18627

* The specialiser, which should not specialise on implicit parameters
  This fixes #18649

There are some lingering worries (see Note [Local implicit
parameters]) but things are much better.

- - - - -
0f3884b0 by Zubin Duggal at 2020-09-15T15:20:23-04:00
Export enrichHie from GHC.Iface.Ext.Ast

This is useful for `ghcide`

- - - - -
b3143f5a by Sylvain Henry at 2020-09-15T15:21:06-04:00
Enhance metrics output

- - - - -
4283feaa by Ryan Scott at 2020-09-15T15:21:43-04:00
Introduce and use DerivClauseTys (#18662)

This switches `deriv_clause_tys` so that instead of using a list of
`LHsSigType`s to represent the types in a `deriving` clause, it now
uses a sum type. `DctSingle` represents a `deriving` clause with no
enclosing parentheses, while `DctMulti` represents a clause with
enclosing parentheses. This makes pretty-printing easier and avoids
confusion between `HsParTy` and the enclosing parentheses in
`deriving` clauses, which are different semantically.

Fixes #18662.

- - - - -
90229c4b by Ryan Scott at 2020-09-16T04:53:22-04:00
Include -f{write,validate}-ide-info in the User's Guide flag reference

Previously, these were omitted from the flag reference due to a
layout oversight in `docs/users_guide/flags.{rst,py}`.

Fixes #18426.

- - - - -
ce42e187 by Ben Gamari at 2020-09-16T04:53:59-04:00
rts: Fix erroneous usage of vsnprintf

As pointed out in #18685, this should be snprintf not vsnprintf. This
appears to be due to a cut-and-paste error.

Fixes #18658.

- - - - -
b695e7d7 by Sylvain Henry at 2020-09-16T04:54:38-04:00
Rename ghci flag into internal-interpreter

"ghci" as a flag name was confusing because it really enables the
internal-interpreter. Even the ghci library had a "ghci" flag...

- - - - -
8af954d2 by Sylvain Henry at 2020-09-16T04:55:17-04:00
Make ghc-boot reexport modules from ghc-boot-th

Packages don't have to import both ghc-boot and ghc-boot-th. It makes
the dependency graph easier to understand and to refactor.

- - - - -
6baa67f5 by Adam Sandberg Eriksson at 2020-09-16T07:45:47-04:00
docs: correct haddock reference

[skip ci]
- - - - -
7cf09ab0 by Simon Peyton Jones at 2020-09-17T01:27:25-04:00
Do absence analysis on stable unfoldings

Ticket #18638 showed that Very Bad Things happen if we fail
to do absence analysis on stable unfoldings.  It's all described
in Note [Absence analysis for stable unfoldings and RULES].

I'm a bit surprised this hasn't bitten us before. Fortunately
the fix is pretty simple.

- - - - -
76d3bcbc by Leif Metcalf at 2020-09-17T01:28:01-04:00
Replace deprecated git --recursive

The --recursive flag of git-clone has been replaced by the
--recurse-submodules flag since git 1.7.4, released in 2011.
- - - - -
da8f4ddd by Richard Eisenberg at 2020-09-17T01:28:38-04:00
Document IfaceTupleTy

- - - - -
3c94c816 by HaskellMouse at 2020-09-17T08:49:51-04:00
Added explicit fixity to (~).

Solves #18252

- - - - -
b612e396 by Cary Robbins at 2020-09-17T08:50:30-04:00
Make the 'IsString (Const a b)' instance polykinded on 'b'

- - - - -
8d0c26c4 by Ben Gamari at 2020-09-17T08:51:08-04:00
rts/win32: Fix missing #include's

These slipped through CI.

- - - - -
76009ec8 by Ben Gamari at 2020-09-17T08:51:08-04:00
Bump Win32 submodule to 2.9.0.0

Also bumps Cabal, directory

- - - - -
147bb598 by Ben Gamari at 2020-09-17T08:51:08-04:00
Bump version to 9.0

Bumps haskeline and haddock submodules.

(cherry picked from commit f218cfc92f7b1a1e01190851972bb9a0e0f3c682)

- - - - -
5c7387f6 by Leif Metcalf at 2020-09-17T08:51:43-04:00
Make Z-encoding comment into a note

- - - - -
c12b3041 by Leif Metcalf at 2020-09-17T08:51:43-04:00
Cosmetic

- - - - -
4f461e1a by Vladislav Zavialov at 2020-09-17T08:52:19-04:00
Parser.y: clarify treatment of @{-# UNPACK #-}

Before this patch, we had this parser production:

	ftype : ...
	      | ftype PREFIX_AT tyarg  { ... }

And 'tyarg' is defined as follows:

	tyarg : atype              { ... }
	      | unpackedness atype { ... }

So one might get the (false) impression that that parser production is
intended to parse things like:

	F @{-# UNPACK #-} X

However, the lexer wouldn't produce PREFIX_AT followed by 'unpackedness',
as the '@' operator followed by '{-' is not considered prefix.

Thus there's no point using 'tyarg' after PREFIX_AT,
and a simple 'atype' will suffice:

	ftype : ...
	      | ftype PREFIX_AT atype  { ... }

This change has no user-facing consequences. It just makes the grammar a
bit more clear.

- - - - -
9dec8600 by Benjamin Maurer at 2020-09-17T08:52:56-04:00
Documented '-m' flags for machine specific instruction extensions.
See #18641 'Documenting the Expected Undocumented Flags'

- - - - -
ca48076a by Sylvain Henry at 2020-09-17T20:04:08-04:00
Introduce OutputableP

Some types need a Platform value to be pretty-printed: CLabel, Cmm
types, instructions, etc.

Before this patch they had an Outputable instance and the Platform value
was obtained via sdocWithDynFlags. It meant that the *renderer* of the
SDoc was responsible of passing the appropriate Platform value (e.g. via
the DynFlags given to showSDoc).  It put the burden of passing the
Platform value on the renderer while the generator of the SDoc knows the
Platform it is generating the SDoc for and there is no point passing a
different Platform at rendering time.

With this patch, we introduce a new OutputableP class:

   class OutputableP a where
      pdoc :: Platform -> a -> SDoc

With this class we still have some polymorphism as we have with `ppr`
(i.e. we can use `pdoc` on a variety of types instead of having a
dedicated `pprXXX` function for each XXX type).

One step closer removing `sdocWithDynFlags` (#10143) and supporting
several platforms (#14335).

- - - - -
e45c8544 by Sylvain Henry at 2020-09-17T20:04:08-04:00
Generalize OutputableP

Add a type parameter for the environment required by OutputableP. It
avoids tying Platform with OutputableP.

- - - - -
37aa224a by Sylvain Henry at 2020-09-17T20:04:08-04:00
Add note about OutputableP

- - - - -
7f2785f2 by Sylvain Henry at 2020-09-17T20:04:08-04:00
Remove pprPrec from Outputable (unused)

- - - - -
b689f3db by Sylvain Henry at 2020-09-17T20:04:46-04:00
Bignum: add clamping naturalToWord (fix #18697)

- - - - -
0799b3de by Ben Gamari at 2020-09-18T15:55:50-04:00
rts/nonmoving: Add missing STM write barrier

When updating a TRec for a TVar already part of a transaction we
previously neglected to add the old value to the update remembered set.
I suspect this was the cause of #18587.

- - - - -
c4921349 by Ben Gamari at 2020-09-18T15:56:25-04:00
rts: Refactor foreign export tracking

This avoids calling `libc` in the initializers which are responsible for
registering foreign exports. We believe this should avoid the corruption
observed in #18548.

See Note [Tracking foreign exports] in rts/ForeignExports.c for an
overview of the new scheme.

- - - - -
40dc9106 by Ben Gamari at 2020-09-18T15:56:25-04:00
rts: Refactor unloading of foreign export StablePtrs

Previously we would allocate a linked list cell for each foreign export.
Now we can avoid this by taking advantage of the fact that they are
already broken into groups.

- - - - -
45fa8218 by Simon Jakobi at 2020-09-19T06:57:36-04:00
Deprecate Data.Semigroup.Option

Libraries email: https://mail.haskell.org/pipermail/libraries/2018-April/028724.html

GHC issue: https://gitlab.haskell.org/ghc/ghc/issues/15028

Corresponding PRs for deepseq:
* https://github.com/haskell/deepseq/pull/55
* https://github.com/haskell/deepseq/pull/57

Bumps the deepseq submodule.

- - - - -
2229d570 by Vladislav Zavialov at 2020-09-19T15:47:24-04:00
Require happy >=1.20

- - - - -
a89c2fba by Ben Gamari at 2020-09-19T15:47:24-04:00
ci.sh: Enforce minimum happy/alex versions

Also, always invoke cabal-install to ensure that happy/alex symlinks are
up-to-date.

- - - - -
2f7ef2fb by Ben Gamari at 2020-09-19T15:47:24-04:00
gitlab-ci: Ensure that cabal-install overwrites existing executables

Previously cabal-install wouldn't overwrite toolchain executables if
they already existed (as they likely would due to caching).

- - - - -
ac213d26 by Ryan Scott at 2020-09-19T15:48:01-04:00
Wire in constraint tuples

This wires in the definitions of the constraint tuple classes. The
key changes are in:

* `GHC.Builtin.Types`, where the `mk_ctuple` function is used to
  define constraint tuple type constructors, data constructors, and
  superclass selector functions, and
* `GHC.Builtin.Uniques`. In addition to wiring in the `Unique`s for
  constraint tuple type and data constructors, we now must wire in
  the superclass selector functions. Luckily, this proves to be not
  that challenging. See the newly added comments.

Historical note: constraint tuples used to be wired-in until about
five years ago, when commit 130e93aab220bdf14d08028771f83df210da340b
turned them into known-key names. This was done as part of a larger
refactor to reduce the number of special cases for constraint tuples,
but the commit message notes that the main reason that constraint
tuples were made known-key (as opposed to boxed/unboxed tuples, which
are wired in) is because it was awkward to wire in the superclass
selectors. This commit solves the problem of wiring in superclass
selectors.

Fixes #18635.

-------------------------
Metric Decrease:
    T10421
    T12150
    T12227
    T12234
    T12425
    T13056
    T13253-spj
    T18282
    T18304
    T5321FD
    T5321Fun
    T5837
    T9961
Metric Decrease (test_env='x86_64-linux-deb9-unreg-hadrian'):
    T12707
Metric Decrease (test_env='x86_64-darwin'):
    T4029
-------------------------

- - - - -
e195dae6 by Wander Hillen at 2020-09-19T15:48:41-04:00
Export singleton function from Data.List

Data.OldList exports a monomorphized singleton function but
it is not re-exported by Data.List. Adding the export to
Data.List causes a conflict with a 14-year old function of the
same name and type by SPJ in GHC.Utils.Misc. We can't just remove
this function because that leads to a problems when building
GHC with a stage0 compiler that does not have singleton in
Data.List yet. We also can't hide the function in GHC.Utils.Misc
since it is not possible to hide a function from a module if the
module does not export the function. To work around this, all
places where the Utils.Misc singleton was used now use a qualified
version like Utils.singleton and in GHC.Utils.Misc we are very
specific about which version we export.

- - - - -
9c1b8ad9 by Sylvain Henry at 2020-09-19T15:49:19-04:00
Bump Stack resolver

- - - - -
d05d13ce by John Ericson at 2020-09-19T15:49:57-04:00
Cinch -fno-warn-name-shadowing down to specific GHCi module

- - - - -
f1accd00 by Sylvain Henry at 2020-09-19T15:49:57-04:00
Add quick-validate Hadrian flavour (quick + -Werror)

- - - - -
8f8d51f1 by Andreas Klebinger at 2020-09-19T15:50:33-04:00
Fix docs who misstated how the RTS treats size suffixes.

They are parsed as multiples of 1024. Not 1000. The docs
used to imply otherwise.

See decodeSize in rts/RtsFlags.c for the logic for this.

- - - - -
2ae0edbd by Andreas Klebinger at 2020-09-19T15:50:33-04:00
Fix a codeblock in ghci.rst

- - - - -
4df3aa95 by Ben Gamari at 2020-09-19T15:51:07-04:00
users guide: Fix various documentation issues

- - - - -
885ecd18 by Ben Gamari at 2020-09-19T15:51:07-04:00
hadrian: Fail on Sphinx syntax errors

Specifically the "Inline literal start-string without end-string"
warning, which typically means that the user neglected to separate
an inline code block from suffix text with a backslash.

- - - - -
b26cd867 by David Feuer at 2020-09-19T15:51:44-04:00
Unpack the MVar in Compact

The `MVar` lock in `Compact` was unnecessarily lazy, creating an extra indirection and wasting two words. Make it strict.
- - - - -
760307cf by Artyom Kuznetsov at 2020-09-19T15:52:21-04:00
Remove GADT self-reference check (#11554, #12081, #12174, fixes #15942)

Reverts 430f5c84dac1eab550110d543831a70516b5cac8

- - - - -
057db94c by Ben Gamari at 2020-09-19T15:52:56-04:00
rts: Drop field initializer on thread_basic_info_data_t

This struct has a number of fields and we only care that the value is
initialized with zeros. This eliminates the warnings noted in #17905.

- - - - -
87e2e2b1 by Vladislav Zavialov at 2020-09-19T23:55:30+03:00
Resolve shift/reduce conflicts with %shift (#17232)

- - - - -
66cba46e by Ben Gamari at 2020-09-20T20:30:57-04:00
testsuite: Unmark T12971 as broken on Windows

It's unclear why, but this no longer seems to fail.

Closes #17945.

- - - - -
816811d4 by Ben Gamari at 2020-09-20T20:30:57-04:00
testsuite: Unmark T5975[ab] as broken on Windows

Sadly it's unclear *why* they have suddenly started working.

Closes #7305.

- - - - -
43a43d39 by Ben Gamari at 2020-09-20T20:30:57-04:00
base/testsuite: Add missing LANGUAGE pragma in ThreadDelay001

Only affected the Windows codepath.

- - - - -
ced8f113 by Ben Gamari at 2020-09-20T20:30:57-04:00
testsuite: Update expected output for outofmem on Windows

The error originates from osCommitMemory rather than getMBlocks.

- - - - -
ea08aead by Ben Gamari at 2020-09-20T20:30:57-04:00
testsuite: Mark some GHCi/Makefile tests as broken on Windows

See #18718.

- - - - -
caf6a5a3 by GHC GitLab CI at 2020-09-20T20:30:57-04:00
testsuite: Fix WinIO error message normalization

This wasn't being applied to stderr.

- - - - -
93ab3e8d by GHC GitLab CI at 2020-09-20T20:30:57-04:00
testsuite: Mark tempfiles as broken on Win32 without WinIO

The old POSIX emulation appears to ignore the user-requested prefix.

- - - - -
9df77fed by GHC GitLab CI at 2020-09-20T20:30:57-04:00
testsuite: Mark TH_spliceE5_prof as broken on Windows

Due to #18721.

- - - - -
1a0f8243 by Ryan Scott at 2020-09-21T16:45:47-04:00
Remove unused ThBrackCtxt and ResSigCtxt

Fixes #18715.

- - - - -
2f222b12 by Ryan Scott at 2020-09-21T16:45:47-04:00
Disallow constraints in KindSigCtxt

This patch cleans up how `GHC.Tc.Validity` classifies `UserTypeCtxt`s
that can only refer to kind-level positions, which is important for
rejecting certain classes of programs. In particular, this patch:

* Introduces a new `TypeOrKindCtxt` data type and
  `typeOrKindCtxt :: UserTypeCtxt -> TypeOrKindCtxt` function, which
  determines whether a `UserTypeCtxt` can refer to type-level
  contexts, kind-level contexts, or both.
* Defines the existing `allConstraintsAllowed` and `vdqAllowed`
  functions in terms of `typeOrKindCtxt`, which avoids code
  duplication and ensures that they stay in sync in the future.

The net effect of this patch is that it fixes #18714, in which it was
discovered that `allConstraintsAllowed` incorrectly returned `True`
for `KindSigCtxt`. Because `typeOrKindCtxt` now correctly classifies
`KindSigCtxt` as a kind-level context, this bug no longer occurs.

- - - - -
aaa51dcf by Ben Gamari at 2020-09-21T16:46:22-04:00
hadrian: Add extra-deps: happy-1.20 to stack.yaml

GHC now requires happy-1.20, which isn't available in LTS-16.14.

Fixes #18726.
- - - - -
6de40f83 by Simon Peyton Jones at 2020-09-22T05:37:24-04:00
Better eta-expansion (again) and don't specilise DFuns

This patch fixes #18223, which made GHC generate an exponential
amount of code.  There are three quite separate changes in here

1.  Re-engineer eta-expansion (again).  The eta-expander was
    generating lots of intermediate stuff, which could be optimised
    away, but which choked the simplifier meanwhile.  Relatively
    easy to kill it off at source.

    See Note [The EtaInfo mechanism] in GHC.Core.Opt.Arity.
    The main new thing is the use of pushCoArg in getArg_maybe.

2.  Stop Specialise specalising DFuns.  This is the cause of a huge
    (and utterly unnecessary) blowup in program size in #18223.
    See Note [Do not specialise DFuns] in GHC.Core.Opt.Specialise.

    I also refactored the Specialise monad a bit... it was silly,
    because it passed on unchanging values as if they were mutable
    state.

3.  Do an extra Simplifer run, after SpecConstra and before
    late-Specialise.  I found (investigating perf/compiler/T16473)
    that failing to do this was crippling *both* SpecConstr *and*
    Specialise.  See Note [Simplify after SpecConstr] in
    GHC.Core.Opt.Pipeline.

    This change does mean an extra run of the Simplifier, but only
    with -O2, and I think that's acceptable.

    T16473 allocates *three* times less with this change.  (I changed
    it to check runtime rather than compile time.)

Some smaller consequences

* I moved pushCoercion, pushCoArg and friends from SimpleOpt
  to Arity, because it was needed by the new etaInfoApp.

  And pushCoValArg now returns a MCoercion rather than Coercion for
  the argument Coercion.

* A minor, incidental improvement to Core pretty-printing

This does fix #18223, (which was otherwise uncompilable. Hooray.  But
there is still a big intermediate because there are some very deeply
nested types in that program.

Modest reductions in compile-time allocation on a couple of benchmarks
    T12425     -2.0%
    T13253    -10.3%

Metric increase with -O2, due to extra simplifier run
    T9233     +5.8%
    T12227    +1.8%
    T15630    +5.0%

There is a spurious apparent increase on heap residency on T9630,
on some architectures at least.  I tried it with -G1 and the residency
is essentially unchanged.

Metric Increase
    T9233
    T12227
    T9630

Metric Decrease
    T12425
    T13253

- - - - -
416bd50e by Simon Peyton Jones at 2020-09-22T05:37:59-04:00
Fix the occurrence analyser

Ticket #18603 demonstrated that the occurrence analyser's
handling of

  local RULES for imported Ids

(which I now call IMP-RULES) was inadequate.  It led the simplifier
into an infnite loop by failing to label a binder as a loop breaker.

The main change in this commit is to treat IMP-RULES in a simple and
uniform way: as extra rules for the local binder.  See
  Note [IMP-RULES: local rules for imported functions]

This led to quite a bit of refactoring.  The result is still tricky,
but it's much better than before, and better documented I think.

Oh, and it fixes the bug.

- - - - -
6fe8a0c7 by Sebastian Graf at 2020-09-22T05:38:35-04:00
PmCheck - Comments only: Replace /~ by ≁

- - - - -
e9501547 by Sebastian Graf at 2020-09-22T05:38:35-04:00
PmCheck: Rewrite inhabitation test

We used to produce inhabitants of a pattern-match refinement type Nabla
in the checker in at least two different and mostly redundant ways:

  1. There was `provideEvidence` (now called
     `generateInhabitingPatterns`) which is used by
     `GHC.HsToCore.PmCheck` to produce non-exhaustive patterns, which
     produces inhabitants of a Nabla as a sub-refinement type where all
     match variables are instantiated.
  2. There also was `ensure{,All}Inhabited` (now called
     `inhabitationTest`) which worked slightly different, but was
     whenever new type constraints or negative term constraints were
     added. See below why `provideEvidence` and `ensureAllInhabited`
     can't be the same function, the main reason being performance.
  3. And last but not least there was the `nonVoid` test, which tested
     that a given type was inhabited. We did use this for strict fields
     and -XEmptyCase in the past.

The overlap of (3) with (2) was always a major pet peeve of mine. The
latter was quite efficient and proven to work for recursive data types,
etc, but could not handle negative constraints well (e.g. we often want
to know if a *refined* type is empty, such as `{ x:[a] | x /= [] }`).

Lower Your Guards suggested that we could get by with just one, by
replacing both functions with `inhabitationTest` in this patch.
That was only possible by implementing the structure of φ constraints
as in the paper, namely the semantics of φ constructor constraints.

This has a number of benefits:

  a. Proper handling of unlifted types and strict fields, fixing #18249,
     without any code duplication between
     `GHC.HsToCore.PmCheck.Oracle.instCon` (was `mkOneConFull`) and
     `GHC.HsToCore.PmCheck.checkGrd`.
  b. `instCon` can perform the `nonVoid` test (3) simply by emitting
     unliftedness constraints for strict fields.
  c. `nonVoid` (3) is thus simply expressed by a call to
     `inhabitationTest`.
  d. Similarly, `ensureAllInhabited` (2), which we called after adding
     type info, now can similarly be expressed as the fuel-based
     `inhabitationTest`.

See the new `Note [Why inhabitationTest doesn't call generateInhabitingPatterns]`
why we still have tests (1) and (2).

Fixes #18249 and brings nice metric decreases for `T17836` (-76%) and
`T17836b` (-46%), as well as `T18478` (-8%) at the cost of a few very
minor regressions (< +2%), potentially due to the fact that
`generateInhabitingPatterns` does more work to suggest the minimal
COMPLETE set.

Metric Decrease:
    T17836
    T17836b

- - - - -
086ef018 by Hécate at 2020-09-23T06:52:08-04:00
Remove the list of loaded modules from the ghci prompt

- - - - -
d7385f70 by Ben Gamari at 2020-09-23T06:52:44-04:00
Bump submodules

* Bump bytestring to 0.10.12.0
* Bump Cabal to 3.4.0.0-rc3
* Bump Win32 to 2.10.0.0

- - - - -
667d6355 by Sylvain Henry at 2020-09-23T20:43:48-04:00
Refactor CLabel pretty-printing

* Don't depend on the selected backend to know if we print Asm or C
  labels: we already have PprStyle to determine this. Moreover even when
  a native backend is used (NCG, LLVM) we may want to C headers
  containing pretty-printed labels, so it wasn't a good predicate
  anyway.

* Make pretty-printing code clearer and avoid partiality

- - - - -
a584366b by Sylvain Henry at 2020-09-23T20:43:48-04:00
Remove sdocWithDynFlags (fix #10143)

- - - - -
a997fa01 by Sylvain Henry at 2020-09-23T20:43:48-04:00
Preliminary work towards removing DynFlags -> Driver.Ppr dependency

- - - - -
31fea307 by Hécate at 2020-09-23T20:44:24-04:00
Remove redundant "do", "return" and language extensions from base

- - - - -
04d64331 by syd at cs-syd.eu at 2020-09-24T13:15:54-04:00
Update Lock.hs with more documentation to make sure that the Boolean return value is clear.

[skip ci]

- - - - -
97cff919 by Simon Peyton Jones at 2020-09-24T13:16:32-04:00
Implement Quick Look impredicativity

This patch implements Quick Look impredicativity (#18126), sticking
very closely to the design in
    A quick look at impredicativity, Serrano et al, ICFP 2020

The main change is that a big chunk of GHC.Tc.Gen.Expr has been
extracted to two new modules
    GHC.Tc.Gen.App
    GHC.Tc.Gen.Head
which deal with typechecking n-ary applications, and the head of
such applications, respectively.  Both contain a good deal of
documentation.

Three other loosely-related changes are in this patch:

* I implemented (partly by accident) points (2,3)) of the accepted GHC
  proposal "Clean up printing of foralls", namely
  https://github.com/ghc-proposals/ghc-proposals/blob/
        master/proposals/0179-printing-foralls.rst
  (see #16320).

  In particular, see Note [TcRnExprMode] in GHC.Tc.Module
  - :type instantiates /inferred/, but not /specified/, quantifiers
  - :type +d instantiates /all/ quantifiers
  - :type +v is killed off

  That completes the implementation of the proposal,
  since point (1) was done in
    commit df08468113ab46832b7ac0a7311b608d1b418c4d
    Author: Krzysztof Gogolewski <krzysztof.gogolewski at tweag.io>
    Date:   Mon Feb 3 21:17:11 2020 +0100
    Always display inferred variables using braces

* HsRecFld (which the renamer introduces for record field selectors),
  is now preserved by the typechecker, rather than being rewritten
  back to HsVar.  This is more uniform, and turned out to be more
  convenient in the new scheme of things.

* The GHCi debugger uses a non-standard unification that allows the
  unification variables to unify with polytypes.  We used to hack
  this by using ImpredicativeTypes, but that doesn't work anymore
  so I introduces RuntimeUnkTv.  See Note [RuntimeUnkTv] in
  GHC.Runtime.Heap.Inspect

Updates haddock submodule.

WARNING: this patch won't validate on its own.  It was too
hard to fully disentangle it from the following patch, on
type errors and kind generalisation.

Changes to tests

* Fixes #9730 (test added)

* Fixes #7026 (test added)

* Fixes most of #8808, except function `g2'` which uses a
  section (which doesn't play with QL yet -- see #18126)
  Test added

* Fixes #1330. NB Church1.hs subsumes Church2.hs, which is now deleted

* Fixes #17332 (test added)

* Fixes #4295

* This patch makes typecheck/should_run/T7861 fail.
  But that turns out to be a pre-existing bug: #18467.
  So I have just made T7861 into expect_broken(18467)

- - - - -
9fa26aa1 by Simon Peyton Jones at 2020-09-24T13:16:32-04:00
Improve kind generalisation, error messages

This patch does two things:

* It refactors GHC.Tc.Errors a bit.  In debugging Quick Look I was
  forced to look in detail at error messages, and ended up doing a bit
  of refactoring, esp in mkTyVarEqErr'.  It's still quite a mess, but
  a bit better, I think.

* It makes a significant improvement to the kind checking of type and
  class declarations. Specifically, we now ensure that if kind
  checking fails with an unsolved constraint, all the skolems are in
  scope.  That wasn't the case before, which led to some obscure error
  messages; and occasional failures with "no skolem info" (eg #16245).

Both of these, and the main Quick Look patch itself, affect a /lot/ of
error messages, as you can see from the number of files changed.  I've
checked them all; I think they are as good or better than before.

Smaller things

* I documented the various instances of VarBndr better.
  See Note [The VarBndr tyep and its uses] in GHC.Types.Var

* Renamed GHC.Tc.Solver.simpl_top to simplifyTopWanteds

* A bit of refactoring in bindExplicitTKTele, to avoid the
  footwork with Either.  Simpler now.

* Move promoteTyVar from GHC.Tc.Solver to GHC.Tc.Utils.TcMType

Fixes #16245 (comment 211369), memorialised as
  typecheck/polykinds/T16245a
Also fixes the three bugs in #18640

- - - - -
6d0ce0eb by Sebastian Graf at 2020-09-24T13:17:07-04:00
PmCheck: Desugar string literal patterns with -XRebindableSyntax correctly (#18708)

Fixes #18708.

- - - - -
007940d2 by Hécate at 2020-09-24T13:17:44-04:00
Namespace the Hadrian linting rule for base

- - - - -
5b727189 by Andreas Klebinger at 2020-09-25T21:10:20-04:00
Make sizeExpr strict in the size threshold to facilitate WW.

- - - - -
dd664031 by Ben Gamari at 2020-09-25T21:10:56-04:00
ci.sh: Factor out common utilities

- - - - -
5b78e865 by Ben Gamari at 2020-09-25T21:10:56-04:00
ci: Add ad-hoc performance testing rule

- - - - -
29885f07 by Zubin Duggal at 2020-09-25T21:11:32-04:00
Stop removing definitions of record fields in GHC.Iface.Ext.Ast

- - - - -
0d6519d9 by Ben Gamari at 2020-09-25T21:12:08-04:00
gitlab-ci: Drop Darwin cleanup job

We now have a proper periodic clean-up script installed on the runners.

- - - - -
277d20af by Sebastian Graf at 2020-09-25T21:12:44-04:00
Add regression tests for #18371

They have been fixed by !3959, I believe.
Fixes #18371.

- - - - -
8edf6056 by Sebastian Graf at 2020-09-25T21:12:44-04:00
Add a regression test for #18609

The egregious performance hits are gone since !4050.
So we fix #18609.

- - - - -
4a1b89a4 by Sebastian Graf at 2020-09-25T21:12:44-04:00
Accept new test output for #17218

The expected test output was plain wrong.
It has been fixed for a long time.
Thus we can close #17218.

- - - - -
51606236 by Sven Tennie at 2020-09-25T21:13:19-04:00
Print RET_BIG stack closures

A RET_BIG closure has a large bitmap that describes it's payload and can
be printed with printLargeBitmap().

Additionally, the output for payload closures of small and big bitmaps is
changed: printObj() is used to print a bit more information about what's
on the stack.

- - - - -
2707c4ea by Arnaud Spiwack at 2020-09-25T21:13:58-04:00
Pattern guards BindStmt always use multiplicity Many

Fixes #18439 .

The rhs of the pattern guard was consumed with multiplicity one, while
the pattern assumed it was Many. We use Many everywhere instead.

This is behaviour consistent with that of `case` expression. See #18738.

- - - - -
92daad24 by Sylvain Henry at 2020-09-25T21:14:36-04:00
Bignum: refactor backend modules

* move backends into GHC.Num.Backend.*
* split backend selection into GHC.Num.Backend and
  GHC.Num.Backend.Selected to avoid duplication with the Check backend

- - - - -
04bc50b3 by Sylvain Henry at 2020-09-25T21:14:36-04:00
Bignum: implement extended GCD (#18427)

- - - - -
6a7dae4b by Krzysztof Gogolewski at 2020-09-25T21:15:14-04:00
Fix typed holes causing linearity errors (#18491)

- - - - -
83407ffc by Krzysztof Gogolewski at 2020-09-25T21:15:53-04:00
Various documentation fixes

* Remove UnliftedFFITypes from conf. Some time ago, this extension
  was undocumented and we had to silence a warning.
  This is no longer needed.
* Use r'' in conf.py. This fixes a Sphinx warning:
  WARNING: Support for evaluating Python 2 syntax is deprecated and will be removed in Sphinx 4.0. Convert docs/users_guide/conf.py to Python 3 syntax.
* Mark GHCForeignImportPrim as documented
* Fix formatting in template_haskell.rst
* Remove 'recursive do' from the list of unsupported items in TH

- - - - -
af1e84e7 by Sebastian Graf at 2020-09-26T05:36:46-04:00
PmCheck: Big refactor of module structure

  * Move everything from `GHC.HsToCore.PmCheck.*` to
    `GHC.HsToCore.Pmc.*` in analogy to `GHC.Tc`, rename exported
    `covCheck*` functions to `pmc*`
  * Rename `Pmc.Oracle` to `Pmc.Solver`
  * Split off the LYG desugaring and checking steps into their own
    modules (`Pmc.Desugar` and `Pmc.Check` respectively)
  * Split off a `Pmc.Utils` module with stuff shared by
    `Pmc.{,Desugar,Check,Solver}`
  * Move `Pmc.Types` to `Pmc.Solver.Types`, add a new `Pmc.Types` module
    with all the LYG types, which form the interfaces between
    `Pmc.{Desugar,Check,Solver,}`.

- - - - -
f08f98e8 by Sebastian Graf at 2020-09-26T05:36:46-04:00
Extract SharedIdEnv into its own module

It's now named `GHC.Types.Unique.SDFM.UniqSDFM`.
The implementation is more clear about its stated goals and supported
operations.

- - - - -
1cde295c by Sylvain Henry at 2020-09-26T05:37:23-04:00
Bignum: add bigNatFromWordArray

Reimplementation of integer-gmp's byteArrayToBigNat#

- - - - -
bda55fa0 by Krzysztof Gogolewski at 2020-09-26T13:18:22-04:00
Make 'undefined x' linear in 'x' (#18731)

- - - - -
160fba4a by Krzysztof Gogolewski at 2020-09-26T13:19:00-04:00
Disallow linear types in FFI (#18472)

- - - - -
e124f2a7 by Krzysztof Gogolewski at 2020-09-26T13:19:36-04:00
Fix handling of function coercions (#18747)

This was broken when we added multiplicity to the function type.

- - - - -
7ff43382 by Vladislav Zavialov at 2020-09-27T03:01:31+03:00
Comments: change outdated reference to mergeOps

As of 686e06c59c3aa6b66895e8a501c7afb019b09e36,
GHC.Parser.PostProcess.mergeOps no longer exists.

[ci skip]

- - - - -
4edf5527 by Vladislav Zavialov at 2020-09-27T10:04:12-04:00
Don't rearrange (->) in the renamer

The parser produces an AST where the (->)
is already associated correctly:

  1. (->) has the least possible precedence
  2. (->) is right-associative

Thus we don't need to handle it in mkHsOpTyRn.

- - - - -
a9ce159b by Vladislav Zavialov at 2020-09-27T10:04:12-04:00
Remove outdated comment in rnHsTyKi

This comment dates back to 3df40b7b78044206bbcffe3e2c0a57d901baf5e8
and does not seem relevant anymore.

- - - - -
583a2070 by Richard Eisenberg at 2020-09-29T00:31:27-04:00
Optimize NthCo (FunCo ...) in coercion opt

We were missing this case previously.

Close #18528.

Metric Decrease:
    T18223
    T5321Fun

- - - - -
b31a3360 by Krzysztof Gogolewski at 2020-09-29T00:32:05-04:00
Linear types: fix kind inference when checking datacons

- - - - -
5830a12c by Vladislav Zavialov at 2020-09-29T00:32:05-04:00
New linear types syntax: a %p -> b (#18459)

Implements GHC Proposal #356

Updates the haddock submodule.

- - - - -
bca4d36d by Vladislav Zavialov at 2020-09-29T00:32:05-04:00
Improve error messages for (a %m) without LinearTypes

Detect when the user forgets to enable the LinearTypes
extension and produce a better error message.

Steals the (a %m) syntax from TypeOperators, the workaround
is to write (a % m) instead.

- - - - -
b9635d0a by Benjamin Maurer at 2020-09-29T00:32:43-04:00
Description of flag `-H` was in 'verbosity options', moved to 'misc'.
Fixes #18699

- - - - -
74c797f6 by Benjamin Maurer at 2020-09-29T00:33:20-04:00
Workaround for #18623: GHC crashes bc. under rlimit for vmem it will reserve
_all_ of it, leaving nothing for, e.g., thread stacks.
Fix will only allocate 2/3rds and check whether remainder is at least large
enough for minimum amount of thread stacks.

- - - - -
4365d77a by Ryan Scott at 2020-09-29T00:33:57-04:00
Add regression test #18501

ghc/ghc!3220 ended up fixing #18501. This patch adds a regression
test for #18501 to ensure that it stays fixed.

- - - - -
8e3f00dd by Sylvain Henry at 2020-09-29T17:24:03+02:00
Make the parser module less dependent on DynFlags

Bump haddock submodule

- - - - -
3ab0d8f7 by Sebastian Graf at 2020-09-30T02:48:27-04:00
PmCheck: Long-distance information for LocalBinds (#18626)

Now `desugarLocalBind` (formerly `desugarLet`) reasons about

  * `FunBind`s that
    * Have no pattern matches (so which aren't functions)
    * Have a singleton match group with a single GRHS
    * (which may have guards)
  * and looks through trivial post-typechecking `AbsBinds` in doing so
    to pick up the introduced renamings.

And desugars to `PmLet` LYG-style guards. Since GRHSs are no longer
denoted simply by `NonEmpty PmGRHS`, but also need to carry a `[PmGrd]`
for the `PmLet`s from `LocalBind`s, I added `PmGRHSs` to capture that.

Since we call out to the desugarer more often, I found that there were
superfluous warnings emitted when desugaring e.g. case expressions.
Thus, I made sure that we deactivate any warnings in the LYG desugaring
steps by the new wrapper function `noCheckDs`.

There's a regression test in `T18626`. Fixes #18626.

- - - - -
f8f60efc by Ben Gamari at 2020-09-30T02:49:03-04:00
testsuite: Mark T12971 as broken on Windows

Due to #17945.

- - - - -
6527fc57 by Ben Gamari at 2020-09-30T02:49:03-04:00
Bump Cabal, hsc2hs, directory, process submodules

Necessary for recent Win32 bump.

- - - - -
df3f5880 by Sylvain Henry at 2020-09-30T02:49:41-04:00
Remove unsafeGlobalDynFlags (#17957, #14597)

There are still global variables but only 3 booleans instead of a single
DynFlags.

- - - - -
9befd94d by Sylvain Henry at 2020-09-30T02:49:41-04:00
Remove unused global variables

Some removed globals variables were still declared in the RTS.

They were removed in the following commits:

* 4fc6524a2a4a0003495a96c8b84783286f65c198
* 0dc7985663efa1739aafb480759e2e2e7fca2a36
* bbd3c399939311ec3e308721ab87ca6b9443f358

- - - - -
7c98699f by Richard Eisenberg at 2020-09-30T02:50:17-04:00
Omit redundant kind equality check in solver

See updated Note [Use loose types in inert set] in
GHC.Tc.Solver.Monad.

Close #18753.

- - - - -
39549826 by Sebastian Graf at 2020-09-30T02:50:54-04:00
Pmc: Don't call exprType on type arguments (#18767)

Fixes #18767.

- - - - -
235e410f by Richard Eisenberg at 2020-09-30T02:51:29-04:00
Regression test for #10709.

Close #10709

- - - - -
5c32655f by Ben Gamari at 2020-09-30T22:31:55-04:00
hadrian/doc: Clarify documentation of key-value configuration
- - - - -
0bb02873 by Sylvain Henry at 2020-10-01T18:34:53-04:00
Add test for T18574

- - - - -
e393f213 by Sylvain Henry at 2020-10-01T18:34:53-04:00
Allow fusion with catMaybes (#18574)

Metric Decrease:
   T18574

- - - - -
d2cfad96 by Fendor at 2020-10-01T18:35:33-04:00
Add mainModuleNameIs and demote mainModIs

Add `mainModuleNameIs` to DynFlags and demote
`mainModIs` to function which uses the homeUnit from DynFlags
it is created from.

- - - - -
fc351ab8 by Fendor at 2020-10-01T18:35:33-04:00
Use HomeUnit for main module without module declaration

- - - - -
dca1cb22 by Fendor at 2020-10-01T18:35:33-04:00
Remove mAIN completely

- - - - -
a5aaceec by Sylvain Henry at 2020-10-01T18:36:11-04:00
Use ADTs for parser errors/warnings

Haskell and Cmm parsers/lexers now report errors and warnings using ADTs
defined in GHC.Parser.Errors. They can be printed using functions in
GHC.Parser.Errors.Ppr.

Some of the errors provide hints with a separate ADT (e.g. to suggest to
turn on some extension). For now, however, hints are not consistent
across all messages. For example some errors contain the hints in the
main message. I didn't want to change any message with this patch. I
expect these changes to be discussed and implemented later.

Surprisingly, this patch enhances performance. On CI
(x86_64/deb9/hadrian, ghc/alloc):

   parsing001         -11.5%
   T13719             -2.7%
   MultiLayerModules  -3.5%
   Naperian           -3.1%

Bump haddock submodule

Metric Decrease:
    MultiLayerModules
    Naperian
    T13719
    parsing001

- - - - -
a946c7ef by Sylvain Henry at 2020-10-01T18:36:11-04:00
Less DynFlags in Header parsing

- - - - -
dafe7943 by Sylvain Henry at 2020-10-01T18:36:11-04:00
Parser: remove some unused imports

These are not reported by GHC because Happy adds {-# OPTIONS_GHC -w #-}

- - - - -
93d5de16 by Sylvain Henry at 2020-10-01T18:36:11-04:00
Don't import GHC.Unit to reduce the number of dependencies

- - - - -
e3655f81 by Sebastian Graf at 2020-10-01T18:36:47-04:00
Don't attach CPR signatures to NOINLINE data structures (#18154)

Because the generated `KindRep`s don't have an unfolding, !3230 did not
actually stop to compute, attach and serialise unnecessary CPR
signatures for them. As already said in
`Note [CPR for data structures]`, that leads to bloated interface
files which is ultimately quadratic for Nested CPR.

So we don't attach any CPR signature to bindings that

  * Are not thunks (because thunks are not in WHNF)
  * Have arity 0 (which means the top-level constructor is not a lambda)

If the data structure has an unfolding, we continue to look through it.
If not (as is the case for `KindRep`s), we look at the unchanged CPR
signature and see `topCprType`, as expected.

- - - - -
ba5965eb by Richard Eisenberg at 2020-10-01T18:37:23-04:00
Add regression test for #18755.

Close #18755

- - - - -
a8018c17 by Vladislav Zavialov at 2020-10-01T18:37:58-04:00
Fix pretty-printing of the mult-polymorphic arrow

A follow-up to !4020 (5830a12c46e7227c276a8a71213057595ee4fc04)

- - - - -
e5523324 by Sylvain Henry at 2020-10-01T18:38:35-04:00
Bignum: add integerNegate RULE

- - - - -
1edd6d21 by Vladislav Zavialov at 2020-10-01T18:39:10-04:00
Refactor: remove rnHsDoc

It did not do any useful work.

- - - - -
a9ae83af by Krzysztof Gogolewski at 2020-10-02T08:00:25-04:00
Fix typos in comments

[skip ci]

- - - - -
b81350bb by Icelandjack at 2020-10-02T08:01:01-04:00
Replaced MkT1 with T1 in type signatures.
- - - - -
3c9beab7 by Vladislav Zavialov at 2020-10-02T13:51:58-04:00
Minor TTG clean-up: comments, unused families, bottom

1. Fix and update section headers in GHC/Hs/Extension.hs
2. Delete the unused 'XCoreAnn' and 'XTickPragma' families
3. Avoid calls to 'panic' in 'pprStmt'

- - - - -
12c06927 by Sylvain Henry at 2020-10-02T13:52:38-04:00
Bignum: implement integerRecipMod (#18427)

- - - - -
8dd4f405 by Sylvain Henry at 2020-10-02T13:52:38-04:00
Bignum: implement integerPowMod (#18427)

Incidentally fix powModInteger which was crashing in integer-gmp for
negative exponents when the modular multiplicative inverse for the base
didn't exist. Now we compute it explicitly with integerRecipMod so that
every backend returns the same result without crashing.

- - - - -
1033a720 by Krzysztof Gogolewski at 2020-10-02T13:53:23-04:00
Reject linearity in kinds in checkValidType (#18780)

Patch taken from https://gitlab.haskell.org/ghc/ghc/-/issues/18624#note_300673

- - - - -
b0ccba66 by Krzysztof Gogolewski at 2020-10-03T19:33:02-04:00
Small documentation fixes

- Fix formatting of code blocks and a few sphinx warnings
- Move the Void# change to 9.2, it was done right after the branch was cut
- Fix typo in linear types documentation
- Note that -Wincomplete-uni-patterns affects lazy patterns

[skip ci]

- - - - -
70dc2f09 by Karel Gardas at 2020-10-03T19:33:06-04:00
fix rts.cabal to use real arch names and not aliasses (fixes #18654)

- - - - -
bc5de347 by Sebastian Graf at 2020-10-05T13:59:24-04:00
Inline `integerDecodeDouble#` and constant-fold `decodeDouble_Int64#` instead

Currently, `integerDecodeDouble#` is known-key so that it can be
recognised in constant folding. But that is very brittle and doesn't
survive worker/wrapper, which we even do for
`NOINLINE` things since #13143.
Also it is a trade-off: The implementation of `integerDecodeDouble#`
allocates an `Integer` box that never cancels aways if we don't inline
it.

Hence we recognise the `decodeDouble_Int64#` primop instead in constant
folding, so that we can inline `integerDecodeDouble#`. As a result,
`integerDecodeDouble#` no longer needs to be known-key.

While doing so, I realised that we don't constant-fold
`decodeFloat_Int#` either, so I also added a RULE for it.

`integerDecodeDouble` is dead, so I deleted it.

Part of #18092. This improves the 32-bit `realToFrac`/`toRational`:

Metric Decrease:
    T10359

- - - - -
802b5e6f by Krzysztof Gogolewski at 2020-10-05T13:59:33-04:00
Fix linear types in TH splices (#18465)

- - - - -
18a3ddf7 by Ben Gamari at 2020-10-05T13:59:33-04:00
rts: Fix integer width in TICK_BUMP_BY

Previously `TICK_BUMP_BY` was defined as

```c
 #define TICK_BUMP_BY(ctr,n) CLong[ctr] = CLong[ctr] + n
```

Yet the tickers themselves were defined as `StgInt`s. This happened to
work out correctly on Linux, where `CLong` is 64-bits. However, it
failed on Windows, where `CLong` is 32-bits, resulting in #18782.

Fixes #18783.

- - - - -
5fc4243b by Rachel at 2020-10-07T14:59:45-04:00
Document profiling flags, warning flags, and no-pie

- - - - -
b41f7c38 by Andreas Klebinger at 2020-10-07T15:00:20-04:00
WinIO: Small changes related to atomic request swaps.

Move the atomix exchange over the Ptr type to an internal module.

Fix a bug caused by us passing ptr-to-ptr instead of ptr to
atomic exchange.

Renamed interlockedExchange to exchangePtr.

I've also added an cas primitive. It turned out we don't need it
for WinIO but I'm leaving it in as it's useful for other things.

- - - - -
948a14e1 by Ben Gamari at 2020-10-07T15:00:55-04:00
gitlab-ci: Fix name of Ubuntu 20.04 image
- - - - -
74d4017b by Sylvain Henry at 2020-10-07T15:01:35-04:00
Fix -flink-rts (#18651)

Before this patch -flink-rts could link with GHC's rts instead of the
selected one.

- - - - -
0e8b923d by Sylvain Henry at 2020-10-07T15:01:35-04:00
Apply suggestion to compiler/GHC/SysTools.hs
- - - - -
d6dff830 by Alan Zimmerman at 2020-10-07T15:02:10-04:00
Preserve as-parsed arrow type for HsUnrestrictedArrow

When linear types are disabled, HsUnrestrictedArrow is treated as
HslinearArrow.

Move this adjustment into the type checking phase, so that the parsed
source accurately represents the source as parsed.

Closes #18791

- - - - -
030c5ce0 by Karel Gardas at 2020-10-07T15:02:48-04:00
hadrian: use stage0 linker to merge objects when done during the stage0

Fixes #18800.

- - - - -
a94db588 by Ben Gamari at 2020-10-07T15:03:23-04:00
testsuite: Allow whitespace before "Metric (in|de)crease"

Several people have struggled with metric change annotations
in their commit messages not being recognized due to the fact that
GitLab's job log inserts a space at the beginning of each line. Teach
the regular expression to accept this whitespace.

- - - - -
e91ddddd by Krzysztof Gogolewski at 2020-10-07T15:04:07-04:00
Misc cleanup

* Include funTyCon in exposedPrimTyCons.
  Every single place using exposedPrimTyCons was adding funTyCon
  manually.
* Remove unused synTyConResKind and ieLWrappedName
* Add recordSelectorTyCon_maybe
* In exprType, panic instead of giving a trace message and dummy output.
  This prevents #18767 reoccurring.
* Fix compilation error in fragile concprog001 test (part of #18732)

- - - - -
386c2d7f by Sylvain Henry at 2020-10-09T08:40:33-04:00
Use UnitId in the backend instead of Unit

In Cmm we can only have real units identified with an UnitId.  Other
units (on-the-fly instantiated units and holes) are only used in
type-checking backpack sessions that don't produce Cmm.

- - - - -
a566c83d by Simon Jakobi at 2020-10-09T08:41:09-04:00
Update containers to v0.6.4.1

Updates containers submodule.

- - - - -
fd984d68 by Tamar Christina at 2020-10-09T08:41:50-04:00
rts: fix race condition in StgCRun

On windows the stack has to be allocated 4k at a time, otherwise we get
a segfault. This is done by using a helper ___chkstk_ms that is provided
by libgcc. The Haskell side already knows how to handle this but we need
to do the same from STG. Previously we would drop the stack in StgRun
but would only make it valid whenever the scheduler loop ran.

This approach was fundamentally broken in that it falls apart when you
take a signal from the OS. We see it less often because you initially
get allocated a 1MB stack block which you have to blow past first.

Concretely this means we must always keep the stack valid.

Fixes #18601.

- - - - -
accdb24a by Sylvain Henry at 2020-10-09T08:42:31-04:00
Expose RTS-only ways (#18651)

Some RTS ways are exposed via settings (ghcThreaded, ghcDebugged) but
not all. It's simpler if the RTS exposes them all itself.

- - - - -
d360f343 by MaxGabriel at 2020-10-09T08:43:11-04:00
Document -Wderiving-typeable

Tracking: #18641

- - - - -
e48cab2a by Krzysztof Gogolewski at 2020-10-09T08:43:49-04:00
Add a flag to indicate that gcc supports -no-pie

Fixes #17919.

- - - - -
f7e2fff9 by Hécate at 2020-10-09T08:44:26-04:00
Add linting of `base` to the CI

- - - - -
45a1d493 by Andreas Klebinger at 2020-10-09T08:45:05-04:00
Use proper RTS flags when collecting residency in perf tests.

Replace options like collect_stats(['peak_megabytes_allocated'],4) with
collect_runtime_residency(4) and so forth. Reason being that the later
also supplies some default RTS arguments which make sure residency does
not fluctuate too much.

The new flags mean we get new (hopefully more accurate) baselines so
accept the stat changes.

-------------------------
Metric Decrease:
     T4029
     T4334
     T7850
Metric Increase:
     T13218
     T7436
-------------------------

- - - - -
ef65b154 by Andreas Klebinger at 2020-10-09T08:45:42-04:00
testsuite/timeout: Fix windows specific errors.

We now seem to use -Werror there. Which caused some long standing
warnings to become errors.

I applied changes to remove the warnings allowing the testsuite to
run on windows as well.

- - - - -
e691a5a0 by Sylvain Henry at 2020-10-09T08:46:22-04:00
Hadrian: add quick-debug flavour

- - - - -
12191a99 by Sylvain Henry at 2020-10-09T08:47:00-04:00
Bignum: match on small Integer/Natural

Previously we only matched on *variables* whose unfoldings were a ConApp
of the form `IS lit#` or `NS lit##`. But we forgot to match on the
ConApp directly... As a consequence, constant folding only worked after
the FloatOut pass which creates bindings for most sub-expressions. With
this patch, matching on bignums works even with -O0 (see bignumMatch
test).

- - - - -
36787bba by Alan Zimmerman at 2020-10-09T08:47:36-04:00
ApiAnnotations : preserve parens in GADTs

A cleanup in 7f418acf61e accidentally discarded some parens in
ConDeclGADT.

Make sure these stay in the AST in a usable format.

Also ensure the AnnLolly does not get lost in a GADT.

- - - - -
32dc7698 by Krzysztof Gogolewski at 2020-10-09T08:48:15-04:00
Linear types: fix roles in GADTs (#18799)

- - - - -
9657f6f3 by Ben Gamari at 2020-10-09T08:48:52-04:00
sdist: Include hadrian sources in source distribution

Previously the make build system's source distribution rules neglected
to include Hadrian's sources.

Fixes #18794.

- - - - -
c832f7e2 by Tamar Christina at 2020-10-09T08:49:33-04:00
winio: fixed timeouts non-threaded.

- - - - -
6f0243ae by Tamar Christina at 2020-10-09T08:50:13-04:00
winio: fix array splat

- - - - -
0fd3d360 by Tamar Christina at 2020-10-09T08:50:51-04:00
winio: fixed bytestring reading interface.

- - - - -
dfaef1ca by Tamar Christina at 2020-10-09T08:51:30-04:00
winio: fixed more data error.

- - - - -
bfdccac6 by Simon Peyton Jones at 2020-10-09T08:52:07-04:00
Fix desugaring of record updates on data families

This fixes a long-standing bug in the desugaring of record
updates for data families, when the latter involves a GADT. It's
all explained in Note [Update for GADTs] in GHC.HsToCore.Expr.

Building the correct cast is surprisingly tricky, as that Note
explains.

Fixes #18809.  The test case (in indexed-types/should_compile/T18809)
contains several examples that exercise the dark corners.

- - - - -
e5c7c9c8 by Ben Gamari at 2020-10-09T08:52:43-04:00
Bump win32-tarballs version to 0.3

This should fix #18774.

- - - - -
ef950b19 by Andreas Klebinger at 2020-10-09T08:53:21-04:00
Add TyCon Set/Env and use them in a few places.

Firstly this improves code clarity.

But it also has performance benefits as we no longer
go through the name of the TyCon to get at it's unique.

In order to make this work the recursion check for TyCon
has been moved into it's own module in order to avoid import
cycles.

- - - - -
fd302e93 by Krzysztof Gogolewski at 2020-10-09T08:54:02-04:00
Add -pgmlm and -optlm flags

!3798 added documentation and semantics for the flags,
but not parsing.

- - - - -
db236ffc by Sylvain Henry at 2020-10-09T08:54:41-04:00
Testsuite: increase timeout for T18223 (#18795)

- - - - -
6a243e9d by Sylvain Henry at 2020-10-09T08:55:21-04:00
Cache HomeUnit in HscEnv (#17957)

Instead of recreating the HomeUnit from the DynFlags every time we need
it, we store it in the HscEnv.

- - - - -
5884fd32 by Fendor at 2020-10-09T19:46:28+02:00
Move File Target parser to library #18596

- - - - -
ea59fd4d by Hécate at 2020-10-10T14:49:59-04:00
Lint the compiler for extraneous LANGUAGE pragmas

- - - - -
22f218b7 by Krzysztof Gogolewski at 2020-10-10T14:50:42-04:00
Linear types: fix quantification in GADTs (#18790)

- - - - -
74ee1237 by Sylvain Henry at 2020-10-10T14:51:20-04:00
Bignum: fix bigNatCompareWord# bug (#18813)

- - - - -
274e21f0 by Hécate at 2020-10-11T10:55:56+02:00
Remove the dependency on the ghc-linters stage

- - - - -
990ea991 by Daniel Rogozin at 2020-10-11T22:20:04+03:00
Fall back to types when looking up data constructors (#18740)

Before this patch, referring to a data constructor in a term-level
context led to a scoping error:

    ghci> id Int
    <interactive>:1:4: error: Data constructor not in scope: Int

After this patch, the renamer falls back to the type namespace
and successfully finds the Int. It is then rejected in the type
checker with a more useful error message:

    <interactive>:1:4: error:
    • Illegal term-level use of the type constructor ‘Int’
        imported from ‘Prelude’ (and originally defined in ‘GHC.Types’)
    • In the first argument of ‘id’, namely ‘Int’
      In the expression: id Int

We also do this for type variables.

- - - - -
9bbc84d2 by Sylvain Henry at 2020-10-12T18:21:51-04:00
DynFlags: refactor DmdAnal

Make demand analysis usable without having to provide DynFlags.

- - - - -
7fdcce6d by Wander Hillen at 2020-10-13T00:12:47-04:00
Initial ShortText code and conversion of package db code

Metric Decrease:
    Naperian
    T10421
    T10421a
    T10547
    T12150
    T12234
    T12425
    T13035
    T18140
    T18304
    T5837
    T6048
    T13253-spj
    T18282
    T18223
    T3064
    T9961
Metric Increase
    T13701

HFSKJH

- - - - -
0a5f2918 by Sylvain Henry at 2020-10-13T00:13:28-04:00
Parser: don't require the HomeUnitId

The HomeUnitId is only used by the Cmm parser and this one has access to
the DynFlags, so it can grab the UnitId of the HomeUnit from them.

Bump haddock submodule

- - - - -
8f4f5794 by HaskellMouse at 2020-10-13T13:05:49+03:00
Unification of Nat and Naturals

This commit removes the separate kind 'Nat' and enables promotion
of type 'Natural' for using as type literal.
It partially solves #10776

Now the following code will be successfully typechecked:
    data C = MkC Natural
    type CC = MkC 1

Before this change we had to create the separate type for promotion
    data C = MkC Natural
    data CP = MkCP Nat
    type CC = MkCP 1

But CP is uninhabited in terms.

For backward compatibility type synonym `Nat` has been made:
    type Nat = Natural

The user's documentation and tests have been updated.
The haddock submodule also have been updated.

- - - - -
0fc1cb54 by Ben Gamari at 2020-10-14T03:42:50-04:00
gitlab-ci: Verify that Hadrian builds with Stack

As noted in #18726, this regularly breaks. Let's test it.

Note that we don't actually perform a build of GHC itself; we merely
test that the Hadrian executable builds and works (by invoking `hadrian
--version`).

- - - - -
89f4d8e9 by Ben Gamari at 2020-10-14T12:03:57-04:00
Bump LLVM version to 10.0

Fixes #18267.

- - - - -
716385c9 by Ryan Scott at 2020-10-14T12:04:34-04:00
Make DataKinds the sole arbiter of kind-level literals (and friends)

Previously, the use of kind-level literals, promoted tuples,
and promoted lists required enabling both `DataKinds` and
`PolyKinds`. This made sense back in a `TypeInType` world, but not so
much now that `TypeInType`'s role has been superseded. Nowadays,
`PolyKinds` only controls kind polymorphism, so let's make `DataKinds`
the thing that controls the other aspects of `TypeInType`, which include
literals, promoted tuples and promoted lists.

There are some other things that overzealously required `PolyKinds`,
which this patch fixes as well:

* Previously, using constraints in kinds (e.g., `data T :: () -> Type`)
  required `PolyKinds`, despite the fact that this is orthogonal to kind
  polymorphism. This now requires `DataKinds` instead.
* Previously, using kind annotations in kinds
  (e.g., `data T :: (Type :: Type) -> Type`) required both `KindSignatures`
  and `PolyKinds`. This doesn't make much sense, so it only requires
  `KindSignatures` now.

Fixes #18831.

- - - - -
ac300a0d by Vladislav Zavialov at 2020-10-14T12:05:11-04:00
Remove "Operator sections" from docs/users_guide/bugs.rst

The issue described in that section was fixed by
2b89ca5b850b4097447cc4908cbb0631011ce979

- - - - -
bf2411a3 by Vladislav Zavialov at 2020-10-14T12:05:11-04:00
Fix PostfixOperators (#18151)

This fixes a regression introduced in 2b89ca5b850b4097447cc4908cbb0631011ce979
See the new T18151x test case.

- - - - -
e60ae8a3 by Fumiaki Kinoshita at 2020-10-14T18:06:12-04:00
Add -Wnoncanonical-{monad,monoid}-instances to standardWarnings

-------------------------
Metric Decrease:
   T12425
Metric Increase:
   T17516
-------------------------

- - - - -
15d2340c by Simon Peyton Jones at 2020-10-14T18:06:48-04:00
Fix some missed opportunities for preInlineUnconditionally

There are two signficant changes here:

* Ticket #18815 showed that we were missing some opportunities for
  preInlineUnconditionally.  The one-line fix is in the code for
  GHC.Core.Opt.Simplify.Utils.preInlineUnconditionally, which now
  switches off only for INLINE pragmas.  I expanded
  Note [Stable unfoldings and preInlineUnconditionally] to explain.

* When doing this I discovered a way in which preInlineUnconditionally
  was occasionally /too/ eager.  It's all explained in
  Note [Occurrences in stable unfoldings] in GHC.Core.Opt.OccurAnal,
  and the one-line change adding markAllMany to occAnalUnfolding.

I also got confused about what NoUserInline meant, so I've renamed
it to NoUserInlinePrag, and changed its pretty-printing slightly.
That led to soem error messate wibbling, and touches quite a few
files, but there is no change in functionality.

I did a nofib run.  As expected, no significant changes.

        Program           Size    Allocs
----------------------------------------
         sphere          -0.0%     -0.4%
----------------------------------------
            Min          -0.0%     -0.4%
            Max          -0.0%     +0.0%
 Geometric Mean          -0.0%     -0.0%

I'm allowing a max-residency increase for T10370, which seems
very irreproducible. (See comments on !4241.)  There is always
sampling error for max-residency measurements; and in any case
the change shows up on some platforms but not others.

Metric Increase:
    T10370

- - - - -
0c4bfed8 by Ben Gamari at 2020-10-14T18:07:25-04:00
users-guide: Add missing :ghc-flag: directive
- - - - -
51c4b851 by Krzysztof Gogolewski at 2020-10-15T04:30:27-04:00
Remove Proxy# argument in Data.Typeable.Internal

No longer neccessary - TypeRep is now indexed, there is no ambiguity.

Also fix a comment in Evidence.hs, IsLabel no longer takes a Proxy#.

- - - - -
809f09e8 by Sylvain Henry at 2020-10-15T04:31:07-04:00
Fix parsing of PIE flags

-fPIE and -fno-PIE flags were (un)setting Opt_PIC instead of Opt_PIE.

Original commit: 3625728a0e3a9b56c2b85ae7ea8bcabdd83ece6a

- - - - -
3d7db148 by Ben Gamari at 2020-10-15T04:31:42-04:00
testsuite: Add missing #include on <stdlib.h>

This otherwise fails on newer Clangs, which warn
more aggressively on undeclared symbols.
- - - - -
998803dc by Andrzej Rybczak at 2020-10-15T11:40:32+02:00
Add flags for annotating Generic{,1} methods INLINE[1] (#11068)

Makes it possible for GHC to optimize away intermediate Generic representation
for more types.

Metric Increase:
    T12227

- - - - -
6b14c418 by GHC GitLab CI at 2020-10-15T21:57:50-04:00
Extend mAX_TUPLE_SIZE to 64

As well a ctuples and sums.

- - - - -
d495f36a by Ben Gamari at 2020-10-15T21:58:27-04:00
rts: Clean-up whitespace in Interpreter

- - - - -
cf10becd by Ben Gamari at 2020-10-15T21:58:27-04:00
compiler/ByteCode: Use strict Maps in bytecode assembler

- - - - -
ae146b53 by Ben Gamari at 2020-10-15T21:58:27-04:00
compiler/ByteCode: Make LocalLabel a newtype

- - - - -
cc536288 by Ben Gamari at 2020-10-15T21:58:27-04:00
compiler/ByteCode: Allow 2^32 local labels

This widens LocalLabel to 2^16, avoiding the crash observed in #14334.

Closes #14334.

- - - - -
1bb0512f by Ben Gamari at 2020-10-16T00:15:31-04:00
mingw: Extract zst toolchain archives

This should have been done when the toolchain was bumped.

- - - - -
bf7c5b6d by Ben Gamari at 2020-10-16T00:15:31-04:00
base: Reintroduce necessary LANGUAGE pragmas

These were incorrectly removed in a recent cleanup commit.

- - - - -
c6b4be4b by Ben Gamari at 2020-10-16T00:15:31-04:00
testsuite: Sort metrics by metric type

Closes #18838.

- - - - -
c7989c93 by Ben Gamari at 2020-10-16T00:15:31-04:00
testsuite: Account for -Wnoncanonical-monoid-instances changes on Windows

- - - - -
330a5433 by Ben Gamari at 2020-10-16T00:15:31-04:00
rts: Add __mingw_vfprintf to RtsSymbols.c

Following the model of the other printf symbols. See Note [Symbols for
MinGW's printf].

- - - - -
c4a69f37 by Ben Gamari at 2020-10-16T00:15:31-04:00
gitlab-ci: Remove allow_failure from Windows jobs

- - - - -
9a9679db by Ben Gamari at 2020-10-16T00:15:31-04:00
gitlab-ci: Fix Hadrian bindist names

- - - - -
07b0db86 by f-a at 2020-10-16T10:14:39-04:00
Clarify Eq documentation #18713
- - - - -
aca0e63b by Ben Gamari at 2020-10-17T10:20:31-04:00
gitlab-ci: Allow doc-tarball job to fail

Currently the Hadrian build appears not to package documentation correctly,
causing doc-tarball to fail due to the Windows build.
- - - - -
b02a9ea7 by Ben Gamari at 2020-10-17T13:26:24-04:00
gitlab-ci: s/allow_newer/allow_failure

Silly mistake on my part.
- - - - -
59d7c9f4 by John Ericson at 2020-10-17T22:01:38-04:00
Skip type family defaults with hs-boot and hsig files

Works around #17190, possible resolution for #17224. New design is is
according to accepted [GHC Propoal 320].

Instances in signatures currently unconditionally opt into associated
family defaults if no explicit instance is given. This is bad for two
reasons:

  1. It constrains possible instantiations to use the default, rather
  than possibly define the associated family differently.

  2. It breaks compilation as type families are unsupported in
  signatures.

This PR simply turns off the filling in of defaults in those cases.
Additionally, it squelches a missing definition warning for hs-boot too
that was only squelched for hsig before.

The downsides are:

  1. There is no way to opt into the default, other than copying its
  definition.

  2. If we fixed type classes in signatures, and wanted instances to
  have to explicitly *out of* rather than into the default, that would
  now be a breaking change.

The change that is most unambiguously goood is harmonizing the warning
squelching between hs-boot or hsig. Maybe they should have the warning
(opt out of default) maybe they shouldn't (opt in to default), but
surely it should be the same for both.

Add hs-boot version of a backpack test regarding class-specified
defaults in instances that appear in an hs-boot file.

The metrics increase is very slight and makes no sense --- at least no
one has figured anything out after this languishing for a while, so I'm
just going to accept it.

Metric Increase:
  T10421a

[GHC proposal 320]: https://github.com/ghc-proposals/ghc-proposals/pull/320

- - - - -
7eb46a09 by Sebastian Graf at 2020-10-17T22:02:13-04:00
Arity: Refactor fixed-point iteration in GHC.Core.Opt.Arity

Arity analysis used to propagate optimistic arity types during
fixed-point interation through the `ArityEnv`'s `ae_cheap_fun` field,
which is like `GHC.Core.Utils.exprIsCheap`, but also considers the
current iteration's optimistic arity, for the binder in question only.

In #18793, we have seen that this is a problematic design, because it
doesn't allow us to look through PAP bindings of that binder.

Hence this patch refactors to a more traditional form with an explicit
signature environment, in which we record the optimistic `ArityType` of
the binder in question (and at the moment is the *only* binder that is
recorded in the arity environment).

- - - - -
6b3eb06a by Sebastian Graf at 2020-10-17T22:02:13-04:00
Arity: Record arity types for non-recursive lets

In #18793, we saw a compelling example which requires us to look at
non-recursive let-bindings during arity analysis and unleash their arity
types at use sites.

After the refactoring in the previous patch, the needed change is quite
simple and very local to `arityType`'s defn for non-recurisve `Let`.

Apart from that, we had to get rid of the second item of
`Note [Dealing with bottoms]`, which was entirely a safety measure and
hindered optimistic fixed-point iteration.

Fixes #18793.

The following metric increases are all caused by this commit and a
result of the fact that we just do more work now:

Metric Increase:
    T3294
    T12545
    T12707

- - - - -
451455fd by Sebastian Graf at 2020-10-17T22:02:13-04:00
Testsuite: Add dead arity analysis tests

We didn't seem to test these old tests at all, judging from their
expected output.

- - - - -
50e9df49 by Dylan Yudaken at 2020-10-17T22:02:50-04:00
When using rts_setInCallCapability, lock incall threads

This diff makes sure that incall threads, when using `rts_setInCallCapability`, will be created as locked.
If the thread is not locked, the thread might end up being scheduled to a different capability.
While this is mentioned in the docs for `rts_setInCallCapability,`, it makes the method significantly less useful as there is no guarantees on the capability being used.

This commit also adds a test to make sure things stay on the correct capability.

- - - - -
0b995759 by DylanZA at 2020-10-17T22:02:50-04:00
Apply suggestion to testsuite/tests/ffi/should_run/all.T
- - - - -
a91dcb66 by Sylvain Henry at 2020-10-17T22:04:02-04:00
Don't get host RTS ways via settings (#18651)

To correctly perform a linking hack for Windows we need to link with the
RTS GHC is currently using. We used to query the RTS ways via the
"settings" file but it is fragile (#18651). The hack hasn't been fixed
to take into account all the ways (Tracing) and it makes linking of GHC
with another RTS more difficult (we need to link with another RTS and to
regenerate the settings file).

So this patch uses the ways reported by the RTS itself
(GHC.Platform.Ways.hostWays) instead of the "settings" file.

- - - - -
d858a3ae by Hécate at 2020-10-17T22:04:38-04:00
Linting corrections

* Bring back LANGUAGE pragmas in GHC.IO.Handle.Lock.Windows
* Exclude some modules that are wrongfully reported

- - - - -
b5b3e34e by Vladislav Zavialov at 2020-10-19T18:16:20-04:00
Implement -Woperator-whitespace (#18834)

This patch implements two related warnings:

  -Woperator-whitespace-ext-conflict
      warns on uses of infix operators that would be parsed
      differently were a particular GHC extension enabled

  -Woperator-whitespace
      warns on prefix, suffix, and tight infix uses of infix
      operators

Updates submodules: haddock, containers.

- - - - -
9648d680 by Sylvain Henry at 2020-10-19T18:16:58-04:00
Remove pdocPrec

pdocPrec was only used in GHC.Cmm.DebugBlock.pprUnwindExpr, so remove
it. OutputableP becomes a one-function class which might be better for
performance.

- - - - -
ee5dcdf9 by Ben Gamari at 2020-10-20T00:47:54-04:00
testsuite: Add test for #18346

This was fixed by 4291bddaea3148908c55f235ee8978e1d9aa6f20.

- - - - -
6c7a5c0c by Krzysztof Gogolewski at 2020-10-20T00:48:29-04:00
Minor comments, update linear types docs

- Update comments: placeHolderTypeTc no longer exists
  "another level check problem" was a temporary comment from linear types
- Use Mult type synonym (reported in #18676)
- Mention multiplicity-polymorphic fields in linear types docs

- - - - -
58a1ca38 by nineonine at 2020-10-20T00:49:07-04:00
Compile modules with `-fobject-code` enabled to byte-code when loaded with `*` prefix in ghci (#8042)

The documentation states that when using :add and :load, the `*` prefix forces a module
to be loaded as byte-code. However, this seems to be ignored when -fobject-code has been
enabled. In that case, the compiled code is always used, regardless of whether the *-form
is used.

The idea is to consult the Targets in HscEnv and check the 'targetAllowObjCode' flag. If
the flag for given module is set, then patch up DynFlags and select compilation backend
accordingly.

This would require a linear scan of course, but that shouldn't be too costly.

- - - - -
59b08a5d by Ben Gamari at 2020-10-20T00:49:41-04:00
gitlab-ci: Rename FLAVOUR -> BUILD_FLAVOUR

Previously the Hadrian jobs used the `FLAVOUR` environment variable to
communicate which flavour `ci.sh` should build whereas `make` used
`BUILD_FLAVOUR`. This caused unnecessary confusion. Consolidate these
two.

- - - - -
ea736839 by Alan Zimmerman at 2020-10-20T08:35:34+01:00
API Annotations: Keep track of unicode for linear arrow notation

The linear arrow can be parsed as `%1 ->` or a direct single token unicode
equivalent.

Make sure that this distinction is captured in the parsed AST by using
IsUnicodeSyntax where it appears, and introduce a new API Annotation,
AnnMult to represent its location when unicode is not used.

Updated haddock submodule

- - - - -
cf3c3bcd by Ben Gamari at 2020-10-20T22:56:31-04:00
testsuite: Mark T12971 as fragile on Windows

Due to #17945.

- - - - -
e2c4a947 by Vladislav Zavialov at 2020-10-21T16:00:30+03:00
Parser regression tests, close #12862 #12446

These issues were fixed by earlier parser changes, most likely related
to whitespace-sensitive parsing.

- - - - -
711929e6 by Simon Peyton Jones at 2020-10-23T02:42:59-04:00
Fix error message location in tcCheckPatSynDecl

Ticket #18856 showed that we were failing to set the right location
for an error message.  Easy to fix, happily.

Turns out that this also improves the error location in test T11010,
which was bogus before but we had never noticed.

- - - - -
730bb590 by Ben Gamari at 2020-10-23T02:43:33-04:00
cmm: Add Note reference to ForeignHint
- - - - -
9ad51bc9 by David Beacham at 2020-10-27T13:59:35-04:00
Fix `instance Bounded a => Bounded (Down a)` (#18716)

* Flip `minBound` and `maxBound` to respect the change in ordering
* Remove awkward `Enum` (and hence `Integral`) instances for
  `Data.Ord.Down`
* Update changelog

- - - - -
eedec53d by Vladislav Zavialov at 2020-10-27T14:00:11-04:00
Version bump: base-4.16 (#18712)

Also bumps upper bounds on base in boot libraries (incl. submodules).

- - - - -
412018c1 by Tamar Christina at 2020-10-27T14:00:49-04:00
winio: simplify logic remove optimization step.

- - - - -
4950dd07 by Ben Gamari at 2020-10-27T14:01:24-04:00
hadrian: Suppress xelatex output unless it fails

As noted in #18835, xelatex produces an absurd amount of output, nearly
all of which is meaningless. Silence this.

Fixes #18835.

- - - - -
f3d8ab2e by Ben Gamari at 2020-10-27T14:02:00-04:00
build system: Clean mingw tarballs

Tamar noticed in !4293 that the build systems fail to clean up the mingw
tarballs directory (`ghc-tarballs`). Fix this in both the make build
system and Hadrian.

- - - - -
0b3d23af by Simon Peyton Jones at 2020-10-27T14:02:34-04:00
Fix two constraint solving problems

This patch fixes two problems in the constraint solver.

* An actual bug #18555: we were floating out a constraint to eagerly,
  and that was ultimately fatal.  It's explained in
  Note [Do not float blocked constraints] in GHC.Core.Constraint.

  This is all very delicate, but it's all going to become irrelevant
  when we stop floating constraints (#17656).

* A major performance infelicity in the flattener.  When flattening
  (ty |> co) we *never* generated Refl, even when there was nothing
  at all to do.  Result: we would gratuitously rewrite the constraint
  to exactly the same thing, wasting work.  Described in #18413, and
  came up again in #18855.

  Solution: exploit the special case by calling the new function
  castCoercionKind1.  See Note [castCoercionKind1] in
  GHC.Core.Coercion

- - - - -
f76c5a08 by Sergei Trofimovich at 2020-10-27T14:03:14-04:00
ghc.mk: amend 'make sdist'

Noticed 'make sdist' failure seen as:

```
"rm" -rf sdistprep/ghc/ghc-9.1.0.20201020/hadrian/_build/ (SRC_DIST_GHC_DIR)/hadrian/dist-newstyle/
/bin/sh: -c: line 0: syntax error near unexpected token `('
```

commit 9657f6f34
("sdist: Include hadrian sources in source distribution")
added a new cleanup path without a variable expantion.

The change adds variable reference. While at it move directory
cleanup to a separate statement.

Amends #18794

Signed-off-by: Sergei Trofimovich <slyfox at gentoo.org>

- - - - -
78b52c88 by David Eichmann at 2020-10-27T14:03:51-04:00
Use config.run_ways for multi_compile_and_run tests

- - - - -
e3fdd419 by Alan Zimmerman at 2020-10-27T14:04:26-04:00
Api Annotations: Introduce AnnPercent for HsExplicitMult

For the case

  foo :: a %p -> b

The location of the '%' is captured, separate from the 'p'

- - - - -
d2a25f42 by Ben Gamari at 2020-10-27T14:05:02-04:00
gitlab-ci: Bump ci-images

Bumps bootstrap compiler to 8.10.1.

- - - - -
28f98b01 by Sebastian Graf at 2020-10-27T14:05:37-04:00
DmdAnal: Kill `is_thunk` case in `splitFV`

The `splitFV` function implements the highly dubious hack
described in `Note [Lazy und unleashable free variables]` in
GHC.Core.Opt.DmdAnal. It arranges it so that demand signatures only
carry strictness info on free variables. Usage info is released through
other means, see the Note. It's purely for analysis performance reasons.

It turns out that `splitFV` has a quite involved case for thunks that
produces slightly different usage signatures and it's not clear why we
need it: `splitFV` is only relevant in the LetDown case and the only
time we call it on thunks is for top-level or local recursive thunks.

Since usage signatures of top-level thunks can only reference other
top-level bindings and we completely discard demand info we have on
top-level things (see the lack of `setIdDemandInfo` in
`dmdAnalTopBind`), the `is_thunk` case is completely irrelevant here.

For local, recursive thunks, the added benefit of the `is_thunk` test
is marginal: We get used-multiple-times in some cases where previously
we had used-once if a recursive thunk has multiple call sites. It's
very unlikely and not a case to optimise for.

So we kill the `is_thunk` case and inline `splitFV` at its call site,
exposing `isWeakDmd` from `GHC.Types.Demand` instead.

The NoFib summary supports this decision:

```
            Min           0.0%     -0.0%
            Max           0.0%     +0.0%
 Geometric Mean          -0.0%     -0.0%
```

- - - - -
60322f93 by Ben Gamari at 2020-10-28T21:11:39-04:00
hadrian: Don't quote metric baseline argument

Previously this was quoted inappropriately.
- - - - -
c85eb372 by Alan Zimmerman at 2020-10-28T21:12:15-04:00
API Annotations: put constructors in alphabetical order

- - - - -
795908dc by John Ericson at 2020-10-29T03:53:14-04:00
Widen acceptance threshold for T10421a

Progress towards #18842. As @sgraf812 points out, widening the window is
dangerous until the exponential described in #17658 is fixed. But this
test has caused enough misery and is low stakes enough that we and
@bgamari think it's worth it in this one case for the time being.

- - - - -
0e9f6def by Sylvain Henry at 2020-10-29T03:53:52-04:00
Split GHC.Driver.Types

I was working on making DynFlags stateless (#17957), especially by
storing loaded plugins into HscEnv instead of DynFlags. It turned out to
be complicated because HscEnv is in GHC.Driver.Types but LoadedPlugin
isn't: it is in GHC.Driver.Plugins which depends on GHC.Driver.Types. I
didn't feel like introducing yet another hs-boot file to break the loop.

Additionally I remember that while we introduced the module hierarchy
(#13009) we talked about splitting GHC.Driver.Types because it contained
various unrelated types and functions, but we never executed. I didn't
feel like making GHC.Driver.Types bigger with more unrelated Plugins
related types, so finally I bit the bullet and split GHC.Driver.Types.

As a consequence this patch moves a lot of things. I've tried to put
them into appropriate modules but nothing is set in stone.

Several other things moved to avoid loops.

* Removed Binary instances from GHC.Utils.Binary for random compiler
  things
* Moved Typeable Binary instances into GHC.Utils.Binary.Typeable: they
  import a lot of things that users of GHC.Utils.Binary don't want to
  depend on.
* put everything related to Units/Modules under GHC.Unit:
  GHC.Unit.Finder, GHC.Unit.Module.{ModGuts,ModIface,Deps,etc.}
* Created several modules under GHC.Types: GHC.Types.Fixity, SourceText,
  etc.
* Split GHC.Utils.Error (into GHC.Types.Error)
* Finally removed GHC.Driver.Types

Note that this patch doesn't put loaded plugins into HscEnv. It's left
for another patch.

Bump haddock submodule

- - - - -
22f5d9a9 by Sylvain Henry at 2020-10-29T03:53:52-04:00
GC: Avoid data race (#18717, #17964)

- - - - -
2ef2fac4 by Ryan Scott at 2020-10-29T04:18:52-04:00
Check for large tuples more thoroughly

This fixes #18723 by:

* Moving the existing `GHC.Tc.Gen.HsType.bigConstraintTuple` validity
  check to `GHC.Rename.Utils.checkCTupSize` for consistency with
  `GHC.Rename.Utils.checkTupSize`, and
* Using `check(C)TupSize` when checking tuple _types_, in addition
  to checking names, expressions, and patterns.

Note that I put as many of these checks as possible in the typechecker so
that GHC can properly distinguish between boxed and constraint tuples. The
exception to this rule is checking names, which I perform in the renamer
(in `GHC.Rename.Env`) so that we can rule out `(,, ... ,,)` and
`''(,, ... ,,)` alike in one fell swoop.

While I was in town, I also removed the `HsConstraintTuple` and
`HsBoxedTuple` constructors of `HsTupleSort`, which are functionally
unused. This requires a `haddock` submodule bump.

- - - - -
7f8be3eb by Richard Eisenberg at 2020-10-29T22:08:13-04:00
Remove unnecessary gender from comments/docs

While, say, alternating "he" and "she" in sequential writing
may be nicer than always using "they", reading code/documentation
is almost never sequential. If this small change makes individuals
feel more welcome in GHC's codebase, that's a good thing.

- - - - -
9902d9ec by Viktor Dukhovni at 2020-10-30T05:28:30-04:00
[skip ci] Fix typo in `callocBytes` haddock.

- - - - -
31fcb55f by Ryan Scott at 2020-10-30T18:52:50-04:00
Split HsConDecl{H98,GADT}Details

Haskell98 and GADT constructors both use `HsConDeclDetails`, which includes
`InfixCon`. But `InfixCon` is never used for GADT constructors, which results
in an awkward unrepresentable state. This removes the unrepresentable state by:

* Renaming the existing `HsConDeclDetails` synonym to `HsConDeclH98Details`,
  which emphasizes the fact that it is now only used for Haskell98-style data
  constructors, and
* Creating a new `HsConDeclGADTDetails` data type with `PrefixConGADT` and
  `RecConGADT` constructors that closely resemble `PrefixCon` and `InfixCon`
  in `HsConDeclH98Details`. The key difference is that `HsConDeclGADTDetails`
  lacks any way to represent infix constructors.

The rest of the patch is refactoring to accommodate the new structure of
`HsConDecl{H98,GADT}Details`. Some highlights:

* The `getConArgs` and `hsConDeclArgTys` functions have been removed, as
  there is no way to implement these functions uniformly for all
  `ConDecl`s. For the most part, their previous call sites now
  pattern match on the `ConDecl`s directly and do different things for
  `ConDeclH98`s and `ConDeclGADT`s.

  I did introduce one new function to make the transition easier:
  `getRecConArgs_maybe`, which extracts the arguments from a `RecCon(GADT)`.
  This is still possible since `RecCon(GADT)`s still use the same representation
  in both `HsConDeclH98Details` and `HsConDeclGADTDetails`, and since the
  pattern that `getRecConArgs_maybe` implements is used in several places,
  I thought it worthwhile to factor it out into its own function.
* Previously, the `con_args` fields in `ConDeclH98` and `ConDeclGADT` were
  both of type `HsConDeclDetails`. Now, the former is of type
  `HsConDeclH98Details`, and the latter is of type `HsConDeclGADTDetails`,
  which are distinct types. As a result, I had to rename the `con_args` field
  in `ConDeclGADT` to `con_g_args` to make it typecheck.

  A consequence of all this is that the `con_args` field is now partial, so
  using `con_args` as a top-level field selector is dangerous. (Indeed, Haddock
  was using `con_args` at the top-level, which caused it to crash at runtime
  before I noticed what was wrong!) I decided to add a disclaimer in the 9.2.1
  release notes to advertise this pitfall.

Fixes #18844. Bumps the `haddock` submodule.

- - - - -
57c3db96 by Ryan Scott at 2020-10-31T02:53:55-04:00
Make typechecker equality consider visibility in ForAllTys

Previously, `can_eq_nc'` would equate `ForAllTy`s regardless of their
`ArgFlag`, including `forall i -> i -> Type` and `forall i. i -> Type`! To fix
this, `can_eq_nc'` now uses the `sameVis` function to first check if the
`ArgFlag`s are equal modulo specificity. I have also updated `tcEqType`'s
implementation to match this behavior. For more explanation on the "modulo
specificity" part, see the new `Note [ForAllTy and typechecker equality]`
in `GHC.Tc.Solver.Canonical`.

While I was in town, I fixed some related documentation issues:

* I added `Note [Typechecker equality]` to `GHC.Tc.Utils.TcType` to describe
  what exactly distinguishes `can_eq_nc'` and `tcEqType` (which implement
  typechecker equality) from `eqType` (which implements definitional equality,
  which does not care about the `ArgFlags` of `ForAllTy`s at all).
* The User's Guide had some outdated prose on the specified/inferred
  distinction being different for types and kinds, a holdover from #15079. This
  is no longer the case on today's GHC, so I removed this prose, added some new
  prose to take its place, and added a regression test for the programs in
  #15079.
* The User's Guide had some _more_ outdated prose on inferred type variables
  not being allowed in `default` type signatures for class methods, which is no
  longer true as of the resolution of #18432.
* The related `Note [Deferred Unification]` was being referenced as
  `Note [Deferred unification]` elsewhere, which made it harder to `grep`
  for. I decided to change the name of the Note to `Deferred unification`
  for consistency with the capitalization style used for most other Notes.

Fixes #18863.

- - - - -
a98593f0 by Sylvain Henry at 2020-10-31T02:54:34-04:00
Refactor numeric constant folding rules

Avoid the use of global pattern synonyms.

1) I think it's going to be helpful to implement constant folding for
   other numeric types, especially Natural which doesn't have a wrapping
   behavior. We'll have to refactor these rules even more so we'd better
   make them less cryptic.

2) It should also be slightly faster because global pattern synonyms
   matched operations for every numeric types instead of the current one:
   e.g., ":**:" pattern was matching multiplication for both Int# and
   Word# types. As we will probably want to implement constant folding
   for other numeric types (Int8#, Int16#, etc.), it is more efficient
   to only match primops for a given type as we do now.

- - - - -
730ef38f by Sylvain Henry at 2020-10-31T02:54:34-04:00
Simplify constant-folding (#18032)

See #18032 for the details.

* Use `Lit (LitNumber _ i)` instead of `isLitValue_maybe` which does
  more work but that is not needed for constant-folding
* Don't export `GHC.Types.Literal.isLitValue_maybe`
* Kill `GHC.Types.Literal.isLitValue` which isn't used

- - - - -
d5a53c1a by Ben Gamari at 2020-10-31T02:55:10-04:00
primops.txt.pp: Move ByteArray# primops to separate file

This file will be generated.

- - - - -
b4278a41 by Ben Gamari at 2020-10-31T02:55:10-04:00
primops: Generate ByteArray# index/read/write primops

Previously these were mostly undocumented and was ripe for potential
inconsistencies.

- - - - -
08e6993a by Sylvain Henry at 2020-10-31T02:55:50-04:00
Move loadDecl into IfaceToCore

- - - - -
cb1f755c by Tamar Christina at 2020-10-31T09:26:56-04:00
winio: Fix unused variables warnings

- - - - -
eb368078 by Andrzej Rybczak at 2020-10-31T09:27:34-04:00
Add testcase for #816

- - - - -
bd4abdc9 by Ben Gamari at 2020-11-01T01:10:31-04:00
testsuite: Add performance test for #18698

- - - - -
dfd27445 by Hécate at 2020-11-01T01:11:09-04:00
Add the proper HLint rules and remove redundant keywords from compiler

- - - - -
ce1bb995 by Hécate at 2020-11-01T08:52:08-05:00
Fix a leak in `transpose`

This patch was authored by David Feuer <david.feuer at gmail.com>

- - - - -
e63db32c by Ben Gamari at 2020-11-01T08:52:44-05:00
Scav: Use bd->gen_no instead of bd->gen->no

This potentially saves a cache miss per scavenge.

- - - - -
1a184ceb by Ben Gamari at 2020-11-01T13:57:10-05:00
rts: Introduce performBlockingMajorGC

- - - - -


17 changed files:

- .gitignore
- .gitlab-ci.yml
- .gitlab/ci.sh
- + .gitlab/common.sh
- .gitlab/linters/check-cpp.py
- .gitlab/test-metrics.sh
- .gitmodules
- CODEOWNERS
- Makefile
- README.md
- aclocal.m4
- + compiler/.hlint.yaml
- compiler/GHC.hs
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/Names/TH.hs
- compiler/GHC/Builtin/PrimOps.hs
- + compiler/GHC/Builtin/RebindableNames.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/da04a8647230fa97e84cfc4b319ce097e2b2d734...1a184ceb8d4c3093fe1a8a5085a747943274a8d9

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/da04a8647230fa97e84cfc4b319ce097e2b2d734...1a184ceb8d4c3093fe1a8a5085a747943274a8d9
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