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Previously, GHC would not warn whenever there was a class instance that
didn't implement a class method whose name begins with an underscore.

Fixes #12959.

Test Plan: make test TEST=WarnMinimal

Reviewers: austin, bgamari, simonpj

Reviewed By: bgamari, simonpj

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2849

GHC Trac Issues: #12959

Reviewers: austin, alanz, bgamari

Reviewed By: alanz, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2836

This fixes some cases of wrong stacks being generated by the profiler.
For background and details on the fix see
`Note [Evaluating functions with profiling]` in `rts/Apply.cmm`.

This does have an impact on allocations for some programs when
profiling.  nofib results:

```
   k-nucleotide          +0.0%     +8.8%    +11.0%    +11.0%      0.0%
         puzzle          +0.0%    +12.5%     0.244     0.246      0.0%
      typecheck           0.0%     +8.7%    +16.1%    +16.2%      0.0%
------------------------------------------------------------------------
--------
            Min          -0.0%     -0.0%    -34.4%    -35.5%    -25.0%
            Max          +0.0%    +12.5%    +48.9%    +49.4%    +10.6%
 Geometric Mean          +0.0%     +0.6%     +2.0%     +1.8%     -0.3%

```

But runtimes don't seem to be affected much, and the examples I looked
at were completely legitimate.  For example, in puzzle we have this:

```
position :: ItemType -> StateType ->  BankType
position Bono = bonoPos
position Edge = edgePos
position Larry = larryPos
position Adam = adamPos
```

where the identifiers on the rhs are all record selectors.  Previously
the profiler gave a stack that looked like

```
  position
  bonoPos
  ...
```

i.e. `bonoPos` was at the same level of the call stack as `position`,
but now it looks like

```
  position
   bonoPos
   ...
```

I used the normaliser from the testsuite to diff the profiling output
from other nofib programs and they all looked better.

Test Plan:
* the broken test passes
* validate
* compiled and ran all of nofib, measured perf, diff'd several .prof
files

Reviewers: niteria, erikd, austin, scpmw, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2804

GHC Trac Issues: #5654, #10007

Currently tracking down where two ASTs disagree is quite difficult. Add a --dump
flag to check-ppr which dumps the respective ASTs to files, which can then be
easily compared with diff, etc.

This deviated by 12% from the expected allocations on Windows.
Yet another case of #12758.

Previously, these functions were hardcoded so as to always `error`
whenever given an argument of 0 or 1. This restriction can be lifted
pretty easily, however.

This requires a slight tweak to `isBuiltInOcc_maybe` in `TysWiredIn` to
allow it to recognize `Unit#` (which is the hard-wired `OccName` for
unboxed 1-tuples).

Fixes #12977.

Test Plan: make test TEST=12977

Reviewers: austin, goldfire, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2847

GHC Trac Issues: #12977

libraries/integer-gmp/gmp/objs/__.SYMDEF SORTED is created by Mac OS
builds.

Test Plan: validate

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2840

`procPointAnalysis` doesn't need to run in `UniqSM` (it consists of a
single `return` and the call to `analyzeCmm` function which is pure).
Making it non-monadic simplifies the code a bit.
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>

Test Plan: validate

Reviewers: austin, bgamari, simonmar

Reviewed By: simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2837

Test Plan: validate

Reviewers: austin, Phyx

Reviewed By: Phyx

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2835

GHC Trac Issues: #12965

D1290 added a panic in a code path that can be reached when
!cGhcWithNativeCodeGen.  This reverts just that part of that patch.

Reviewers: austin, simonmar, bgamari, xnyhps

Reviewed By: simonmar

Subscribers: xnyhps, thomie

Differential Revision: https://phabricator.haskell.org/D2831

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2830

Reviewers: austin, bgamari, RyanGlScott

Reviewed By: bgamari, RyanGlScott

Subscribers: RyanGlScott, thomie

Differential Revision: https://phabricator.haskell.org/D2824

Mingw-w64 does a stupid thing. They set the FPU precision to extended
mode by default.  The reasoning is that it's for compatibility with GNU
Linux ported libraries. However the problem is this is incompatible with
the standard Windows double precision mode.  In fact, if we create a new
OS thread then Windows will reset the FPU to double precision mode.  So
we end up with a weird state where the main thread by default has a
different precision than any child threads.

Test Plan: ./validate new test T7289

Reviewers: simonmar, austin, bgamari, erikd

Reviewed By: simonmar

Subscribers: thomie, #ghc_windows_task_force

Differential Revision: https://phabricator.haskell.org/D2819

GHC Trac Issues: #7289

This patch implements the display of constraints in the error message
for typed holes.

Test Plan: validate, read docs

Reviewers: simonpj, austin, bgamari

Reviewed By: simonpj, bgamari

Subscribers: simonpj, thomie

Differential Revision: https://phabricator.haskell.org/D2767

GHC Trac Issues: #10614

Before the change result of expression
    ArchSupportsSMP="$(if $(filter $(ARM_ISA),ARMv5 ARMv6),NO,YES)"
to evaluate to
    ArchSupportsSMP="YES"

After the change it's
    ArchSupportsSMP=YES

Thanks to orion for the fix!

Fixes Trac #12981
Signed-off-by: Sergei Trofimovich <siarheit@google.com>

[ci skip]

Summary:
If we didn't load the orphans, we might conclude an instance
is not implemented when it is.  See test bkp42.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2841

Reviewers: austin, alanz, bgamari

Reviewed By: alanz, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2834

Test Plan: validate

Reviewers: simonpj, austin, bgamari, goldfire

Reviewed By: bgamari, goldfire

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2829

Old test used timeouts that leads to the various sporadic errors.
Tet was rewritten to not use timeouts.

Reviewers: austin, erikd, simonmar, bgamari

Reviewed By: simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2827

GHC Trac Issues: #12956

Test Plan: ./validate

Reviewers: austin, bgamari, erikd, simonmar

Reviewed By: simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2825

Reviewers: austin, simonmar, erikd, bgamari

Reviewed By: erikd, bgamari

Subscribers: angerman, thomie

Differential Revision: https://phabricator.haskell.org/D2823

Ticket #9696 reported that `readRawBufferPtr` and `writeRawBufferPtr`
allocated unnecessarily. The binding is question was,
```
let {
  buf_s4VD [Dmd=<L,U(U)>] :: GHC.Ptr.Ptr GHC.Word.Word8
  [LclId, Unf=OtherCon []] =
      NO_CCS GHC.Ptr.Ptr! [ds1_s4Vy];
} in
  case
      GHC.IO.FD.$wreadRawBufferPtr
          Main.main5
          0#
          0#
          buf_s4VD
          Main.main4
          Main.main3
          GHC.Prim.void#
  of ...
```
The problem was that GHC apparently couldn't tell that
`readRawBufferPtr` would always demand the buffer. Here we simple add
bang patterns on all of the small arguments of these functions to ensure
that worker/wrappers can eliminate these allocations.

Test Plan: Look at STG produced by testcase in #9696, verify no
allocations

Reviewers: austin, hvr, simonmar

Reviewed By: simonmar

Subscribers: RyanGlScott, simonmar, thomie

Differential Revision: https://phabricator.haskell.org/D2813

GHC Trac Issues: #9696

This reverts commit bc3d37da.

Summary:
Previously, we only checked to recompile if a signature we
previously depended on changed; however, if the -unit-id
settings changed, this could have resulted in more or less
signatures needing to be merged in; we weren't checking
for this case.

(Note that this logic is irrelevant for normal module imports,
which we also check using -unit-id, as we record each import
and redo it, forcing a recompile if the result changed.)
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2832

Summary:
Previously we would just let compilation proceed along until
we tried to pull up the Module for the hsig file, and get
main:A instead of <A>, and get a mysterious error.  Check
for this earlier!

Fixes #12955.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2815

GHC Trac Issues: #12955

Summary:
At the moment, data and type declarations using infix formatting produce the
same AST as those using prefix.

So

    type a ++ b = c

and

    type (++) a b = c

cannot be distinguished in the parsed source, without looking at the OccName
details of the constructor being defined.

Having access to the OccName requires an additional constraint which explodes
out over the entire AST because of its recursive definitions.

In keeping with moving the parsed source to more directly reflect the source
code as parsed, add a specific flag to the declaration to indicate the fixity,
as used in a Match now too.

Note: this flag is to capture the fixity used for the lexical definition of the
type, primarily for use by ppr and ghc-exactprint.

Updates haddock submodule.

Test Plan: ./validate

Reviewers: mpickering, goldfire, bgamari, austin

Reviewed By: mpickering

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2828

GHC Trac Issues: #12942

This patch makes GHC's floating more robust, by allowing it
to float unboxed expressions of at least some common types.

See Note [Floating MFEs of unlifted type] in SetLevels.

This was all provoked by Trac #12603

I had the environments wrong so that CSE could mis-clone
an expression, if the uniques just happened to be badly
arranged.  It's hard to trigger the bug, so I can't make
a reliable test case.

Happily the fix is easy.

Test seems to randomly fail on harbormaster. Disabling it until it can be fixed.

Test Plan: make test TEST=T12903

Reviewers: austin, bgamari, simonmar, mpickering

Reviewed By: mpickering

Subscribers: mpickering, thomie, qnikst

Differential Revision: https://phabricator.haskell.org/D2821

GHC Trac Issues: #12903

I'd forgotten to turn [W] + [D] constraints back into [WD]
in dropDerivedSimples; and that led to Trac #12936.

Fortunately the fix is simple.

We try to prune solved implication constraints, but it's a
bit tricky because of our desire to correctly report unused
'givens'.  This patch improves matters a bit... in tracig some
other bug I saw lots of empty constraints lying around!

Summary:
The use of globals is quite painful when multiple rts are loaded, e.g.
when plugins are loaded, which bring in a second rts. The sharedCAF
appraoch was employed for the FastStringTable; I've taken the libery
to extend this to the other globals I could find.

This is a reboot of D2575, that should hopefully not exhibit the same
windows build issues.

Reviewers: Phyx, simonmar, goldfire, bgamari, austin, hvr, erikd

Reviewed By: Phyx, simonmar, bgamari

Subscribers: mpickering, thomie

Differential Revision: https://phabricator.haskell.org/D2773

Summary:
Everytime we upgrade the GCC version this wrapper needed updating.
This is a big fragile and we kept forgetting it.

Instead automate it so we don't have to worry about it.

Test Plan: ./validate

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: thomie, #ghc_windows_task_force

Differential Revision: https://phabricator.haskell.org/D2820

GHC Trac Issues: #12871

Reviewers: bgamari, austin, erikd, simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2818

Test Plan: Validate on Windows, ensure that linking works.

Reviewers: Phyx, austin, erikd, simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2817

Yet another reason why no change to too small to validate. Arg.

Due to #11317.

After talking to Richard, he and I concluded that choosing the rather
common name `Newtype` to represent the corresponding deriving strategy
in Template Haskell was a poor choice of name. I've opted to rename it
to something less common (`NewtypeStrategy`) while we still have time. I
also renamed the corrsponding datatype in the GHC internals so as to
match it.

Reviewers: austin, goldfire, hvr, bgamari

Reviewed By: bgamari

Subscribers: thomie, mpickering

Differential Revision: https://phabricator.haskell.org/D2814

GHC Trac Issues: #10598

This is so that global test flags that control the error formatting are
propagated correctly.  This patch is kind of related to: D2718

The stderr for API annotations is ignored entirely now per @alanz's
suggestion.

Test Plan: validate

Reviewers: thomie, alanz, austin, bgamari

Reviewed By: bgamari

Subscribers: alanz

Differential Revision: https://phabricator.haskell.org/D2808