[Git][ghc/ghc][wip/andreask/spark-gc] 250 commits: Add unsafePtrEquality# restricted to UnliftedTypes

Thu Jan 12 12:48:36 UTC 2023

Andreas Klebinger pushed to branch wip/andreask/spark-gc at Glasgow Haskell Compiler / GHC

Commits:
9d61c182 by Oleg Grenrus at 2022-11-22T15:59:34-05:00
Add unsafePtrEquality# restricted to UnliftedTypes

- - - - -
e817c871 by Jonathan Dowland at 2022-11-22T16:00:14-05:00
utils/unlit: adjust parser to match Report spec

The Haskell 2010 Report says that, for Latex-style Literate format,
"Program code begins on the first line following a line that begins
\begin{code}". (This is unchanged from the 98 Report)

However the unlit.c implementation only matches a line that contains
"\begin{code}" and nothing else. One consequence of this is that one
cannot suffix Latex options to the code environment. I.e., this does
not work:

\begin{code}[label=foo,caption=Foo Code]

Adjust the matcher to conform to the specification from the Report.

The Haskell Wiki currently recommends suffixing a '%' to \begin{code}
in order to deliberately hide a code block from Haskell. This is bad
advice, as it's relying on an implementation quirk rather than specified
behaviour. None-the-less, some people have tried to use it, c.f.
<https://mail.haskell.org/pipermail/haskell-cafe/2009-September/066780.html>

An alternative solution is to define a separate, equivalent Latex
environment to "code", that is functionally identical in Latex but
ignored by unlit. This should not be a burden: users are required to
manually define the code environment anyway, as it is not provided
by the Latex verbatim or lstlistings packages usually used for
presenting code in documents.

Fixes #3549.

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0b7fef11 by Teo Camarasu at 2022-11-23T12:44:33-05:00
Fix eventlog all option

Previously it didn't enable/disable nonmoving_gc and ticky event types

Fixes #21813

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04d0618c by Arnaud Spiwack at 2022-11-23T12:45:14-05:00
Expand Note [Linear types] with the stance on linting linearity

Per the discussion on #22123

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e1538516 by Lawton Nichols at 2022-11-23T12:45:55-05:00
Add documentation on custom Prelude modules (#22228)

Specifically, custom Prelude modules that are named `Prelude`.

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b5c71454 by Sylvain Henry at 2022-11-23T12:46:35-05:00
Don't let configure perform trivial substitutions (#21846)

Hadrian now performs substitutions, especially to generate .cabal files
from .cabal.in files. Two benefits:

1. We won't have to re-configure when we modify thing.cabal.in. Hadrian
   will take care of this for us.

2. It paves the way to allow the same package to be configured
   differently by Hadrian in the same session. This will be useful to
   fix #19174: we want to build a stage2 cross-compiler for the host
   platform and a stage1 compiler for the cross target platform in the
   same Hadrian session.

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99aca26b by nineonine at 2022-11-23T12:47:11-05:00
CApiFFI: add ConstPtr for encoding const-qualified pointer return types (#22043)

Previously, when using `capi` calling convention in foreign declarations,
code generator failed to handle const-cualified pointer return types.
This resulted in CC toolchain throwing `-Wincompatible-pointer-types-discards-qualifiers`
warning.

`Foreign.C.Types.ConstPtr` newtype was introduced to handle these cases -
special treatment was put in place to generate appropritetly qualified C
wrapper that no longer triggers the above mentioned warning.

Fixes #22043

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040bfdc3 by M Farkas-Dyck at 2022-11-23T21:59:03-05:00
Scrub some no-warning pragmas.

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178c1fd8 by Vladislav Zavialov at 2022-11-23T21:59:39-05:00
Check if the SDoc starts with a single quote (#22488)

This patch fixes pretty-printing of character literals
inside promoted lists and tuples.

When we pretty-print a promoted list or tuple whose first element
starts with a single quote, we want to add a space between the opening
bracket and the element:

	'[True]    -- ok
	'[ 'True]  -- ok
	'['True]   -- not ok

If we don't add the space, we accidentally produce a character
literal '['.

Before this patch, pprSpaceIfPromotedTyCon inspected the type as an AST
and tried to guess if it would be rendered with a single quote. However,
it missed the case when the inner type was itself a character literal:

	'[ 'x']  -- ok
	'['x']   -- not ok

Instead of adding this particular case, I opted for a more future-proof
solution: check the SDoc directly. This way we can detect if the single
quote is actually there instead of trying to predict it from the AST.
The new function is called spaceIfSingleQuote.

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11627c42 by Matthew Pickering at 2022-11-23T22:00:15-05:00
notes: Fix references to HPT space leak note

Updating this note was missed when updating the HPT to the HUG.

Fixes #22477

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86ff1523 by Andrei Borzenkov at 2022-11-24T17:24:51-05:00
Convert diagnostics in GHC.Rename.Expr to proper TcRnMessage (#20115)

Problem: avoid usage of TcRnMessageUnknown

Solution:
The following `TcRnMessage` messages has been introduced:
  TcRnNoRebindableSyntaxRecordDot
  TcRnNoFieldPunsRecordDot
  TcRnIllegalStaticExpression
  TcRnIllegalStaticFormInSplice
  TcRnListComprehensionDuplicateBinding
  TcRnEmptyStmtsGroup
  TcRnLastStmtNotExpr
  TcRnUnexpectedStatementInContext
  TcRnIllegalTupleSection
  TcRnIllegalImplicitParameterBindings
  TcRnSectionWithoutParentheses

Co-authored-by: sheaf <sam.derbyshire at gmail.com>

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d198a19a by Cheng Shao at 2022-11-24T17:25:29-05:00
rts: fix missing Arena.h symbols in RtsSymbols.c

It was an unfortunate oversight in !8961 and broke devel2 builds.

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5943e739 by Bodigrim at 2022-11-25T04:38:28-05:00
Assorted fixes to avoid Data.List.{head,tail}

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1f1b99b8 by sheaf at 2022-11-25T04:38:28-05:00
Review suggestions for assorted fixes to avoid Data.List.{head,tail}

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13d627bb by Vladislav Zavialov at 2022-11-25T04:39:04-05:00
Print unticked promoted data constructors (#20531)

Before this patch, GHC unconditionally printed ticks before promoted
data constructors:

	ghci> type T = True  -- unticked (user-written)
	ghci> :kind! T
	T :: Bool
	= 'True              -- ticked (compiler output)

After this patch, GHC prints ticks only when necessary:

	ghci> type F = False    -- unticked (user-written)
	ghci> :kind! F
	F :: Bool
	= False                 -- unticked (compiler output)

	ghci> data False        -- introduce ambiguity
	ghci> :kind! F
	F :: Bool
	= 'False                -- ticked by necessity (compiler output)

The old behavior can be enabled by -fprint-redundant-promotion-ticks.

Summary of changes:
* Rename PrintUnqualified to NamePprCtx
* Add QueryPromotionTick to it
* Consult the GlobalRdrEnv to decide whether to print a tick (see mkPromTick)
* Introduce -fprint-redundant-promotion-ticks

Co-authored-by: Artyom Kuznetsov <hi at wzrd.ht>

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d10dc6bd by Simon Peyton Jones at 2022-11-25T22:31:27+00:00
Fix decomposition of TyConApps

Ticket #22331 showed that we were being too eager to decompose
a Wanted TyConApp, leading to incompleteness in the solver.

To understand all this I ended up doing a substantial rewrite
of the old Note [Decomposing equalities], now reborn as
Note [Decomposing TyConApp equalities]. Plus rewrites of other
related Notes.

The actual fix is very minor and actually simplifies the code: in
`can_decompose` in `GHC.Tc.Solver.Canonical.canTyConApp`, we now call
`noMatchableIrreds`.  A closely related refactor: we stop trying to
use the same "no matchable givens" function here as in
`matchClassInst`.  Instead split into two much simpler functions.

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2da5c38a by Will Hawkins at 2022-11-26T04:05:04-05:00
Redirect output of musttail attribute test

Compilation output from test for support of musttail attribute leaked to
the console.

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0eb1c331 by Cheng Shao at 2022-11-28T08:55:53+00:00
Move hs_mulIntMayOflo cbits to ghc-prim

It's only used by wasm NCG at the moment, but ghc-prim is a more
reasonable place for hosting out-of-line primops. Also, we only need a
single version of hs_mulIntMayOflo.

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36b53a9d by Cheng Shao at 2022-11-28T09:05:57+00:00
compiler: generate ccalls for clz/ctz/popcnt in wasm NCG

We used to generate a single wasm clz/ctz/popcnt opcode, but it's
wrong when it comes to subwords, so might as well generate ccalls for
them. See #22470 for details.

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d4134e92 by Cheng Shao at 2022-11-28T23:48:14-05:00
compiler: remove unused MO_U_MulMayOflo

We actually only emit MO_S_MulMayOflo and never emit MO_U_MulMayOflo anywhere.

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8d15eadc by Apoorv Ingle at 2022-11-29T03:09:31-05:00
Killing cc_fundeps, streamlining kind equality orientation, and type equality processing order

Fixes: #217093
Associated to #19415

This change
* Flips the orientation of the the generated kind equality coercion in canEqLHSHetero;
* Removes `cc_fundeps` in CDictCan as the check was incomplete;
* Changes `canDecomposableTyConAppOk` to ensure we process kind equalities before type equalities and avoiding a call to `canEqLHSHetero` while processing wanted TyConApp equalities
* Adds 2 new tests for validating the change
   - testsuites/typecheck/should_compile/T21703.hs and
   - testsuites/typecheck/should_fail/T19415b.hs (a simpler version of T19415.hs)
* Misc: Due to the change in the equality direction some error messages now have flipped type mismatch errors
* Changes in Notes:
  - Note [Fundeps with instances, and equality orientation] supercedes Note [Fundeps with instances]
  - Added Note [Kind Equality Orientation] to visualize the kind flipping
  - Added Note [Decomposing Dependent TyCons and Processing Wanted Equalties]

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646969d4 by Krzysztof Gogolewski at 2022-11-29T03:10:13-05:00
Change printing of sized literals to match the proposal

Literals in Core were printed as e.g. 0xFF#16 :: Int16#.
The proposal 451 now specifies syntax 0xFF#Int16.
This change affects the Core printer only - more to be done later.

Part of #21422.

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02e282ec by Simon Peyton Jones at 2022-11-29T03:10:48-05:00
Be a bit more selective about floating bottoming expressions

This MR arranges to float a bottoming expression to the top
only if it escapes a value lambda.

See #22494 and Note [Floating to the top] in SetLevels.

This has a generally beneficial effect in nofib

+-------------------------------++----------+
|                               ||tsv (rel) |
+===============================++==========+
|           imaginary/paraffins ||   -0.93% |
|                imaginary/rfib ||   -0.05% |
|                      real/fem ||   -0.03% |
|                    real/fluid ||   -0.01% |
|                   real/fulsom ||   +0.05% |
|                   real/gamteb ||   -0.27% |
|                       real/gg ||   -0.10% |
|                   real/hidden ||   -0.01% |
|                      real/hpg ||   -0.03% |
|                      real/scs ||  -11.13% |
|         shootout/k-nucleotide ||   -0.01% |
|               shootout/n-body ||   -0.08% |
|   shootout/reverse-complement ||   -0.00% |
|        shootout/spectral-norm ||   -0.02% |
|             spectral/fibheaps ||   -0.20% |
|           spectral/hartel/fft ||   -1.04% |
|         spectral/hartel/solid ||   +0.33% |
|     spectral/hartel/wave4main ||   -0.35% |
|                 spectral/mate ||   +0.76% |
+===============================++==========+
|                     geom mean ||   -0.12% |

The effect on compile time is generally slightly beneficial

Metrics: compile_time/bytes allocated
----------------------------------------------
MultiLayerModulesTH_OneShot(normal)  +0.3%
                  PmSeriesG(normal)  -0.2%
                  PmSeriesT(normal)  -0.1%
                     T10421(normal)  -0.1%
                    T10421a(normal)  -0.1%
                     T10858(normal)  -0.1%
                     T11276(normal)  -0.1%
                    T11303b(normal)  -0.2%
                     T11545(normal)  -0.1%
                     T11822(normal)  -0.1%
                     T12150(optasm)  -0.1%
                     T12234(optasm)  -0.3%
                     T13035(normal)  -0.2%
                     T16190(normal)  -0.1%
                     T16875(normal)  -0.4%
                    T17836b(normal)  -0.2%
                     T17977(normal)  -0.2%
                    T17977b(normal)  -0.2%
                     T18140(normal)  -0.1%
                     T18282(normal)  -0.1%
                     T18304(normal)  -0.2%
                    T18698a(normal)  -0.1%
                     T18923(normal)  -0.1%
                     T20049(normal)  -0.1%
                    T21839r(normal)  -0.1%
                      T5837(normal)  -0.4%
                      T6048(optasm)  +3.2% BAD
                      T9198(normal)  -0.2%
                      T9630(normal)  -0.1%
       TcPlugin_RewritePerf(normal)  -0.4%
             hard_hole_fits(normal)  -0.1%

                          geo. mean  -0.0%
                          minimum    -0.4%
                          maximum    +3.2%

The T6048 outlier is hard to pin down, but it may be the effect of
reading in more interface files definitions. It's a small program for
which compile time is very short, so I'm not bothered about it.

Metric Increase:
    T6048

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ab23dc5e by Ben Gamari at 2022-11-29T03:11:25-05:00
testsuite: Mark unpack_sums_6 as fragile due to #22504

This test is explicitly dependent upon runtime, which is generally not
appropriate given that the testsuite is run in parallel and generally
saturates the CPU.

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def47dd3 by Ben Gamari at 2022-11-29T03:11:25-05:00
testsuite: Don't use grep -q in unpack_sums_7

`grep -q` closes stdin as soon as it finds the pattern it is looking
for, resulting in #22484.

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cc25d52e by Sylvain Henry at 2022-11-29T09:44:31+01:00
Add Javascript backend

Add JS backend adapted from the GHCJS project by Luite Stegeman.

Some features haven't been ported or implemented yet. Tests for these
features have been disabled with an associated gitlab ticket.

Bump array submodule

Work funded by IOG.

Co-authored-by: Jeffrey Young <jeffrey.young at iohk.io>
Co-authored-by: Luite Stegeman <stegeman at gmail.com>
Co-authored-by: Josh Meredith <joshmeredith2008 at gmail.com>

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68c966cd by sheaf at 2022-11-30T09:31:25-05:00
Fix @since annotations on WithDict and Coercible

Fixes #22453

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a3a8e9e9 by Simon Peyton Jones at 2022-11-30T09:32:03-05:00
Be more careful in GHC.Tc.Solver.Interact.solveOneFromTheOther

We were failing to account for the cc_pend_sc flag in this
important function, with the result that we expanded superclasses
forever.

Fixes #22516.

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a9d9b8c0 by Simon Peyton Jones at 2022-11-30T09:32:03-05:00
Use mkNakedFunTy in tcPatSynSig

As #22521 showed, in tcPatSynSig we make a "fake type" to
kind-generalise; and that type has unzonked type variables in it. So
we must not use `mkFunTy` (which checks FunTy's invariants) via
`mkPhiTy` when building this type.  Instead we need to use
`mkNakedFunTy`.

Easy fix.

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31462d98 by Andreas Klebinger at 2022-11-30T14:50:58-05:00
Properly cast values when writing/reading unboxed sums.

Unboxed sums might store a Int8# value as Int64#. This patch
makes sure we keep track of the actual value type.

See Note [Casting slot arguments] for the details.

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10a2a7de by Oleg Grenrus at 2022-11-30T14:51:39-05:00
Move Void to GHC.Base...

This change would allow `Void` to be used deeper in module graph.
For example exported from `Prelude` (though that might be already
possible).

Also this change includes a change `stimes @Void _ x = x`,
https://github.com/haskell/core-libraries-committee/issues/95

While the above is not required, maintaining old stimes behavior
would be tricky as `GHC.Base` doesn't know about `Num` or `Integral`,
which would require more hs-boot files.

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b4cfa8e2 by Sebastian Graf at 2022-11-30T14:52:24-05:00
DmdAnal: Reflect the `seq` of strict fields of a DataCon worker (#22475)

See the updated `Note [Data-con worker strictness]`
and the new `Note [Demand transformer for data constructors]`.

Fixes #22475.

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d87f28d8 by Baldur Blöndal at 2022-11-30T21:16:36+01:00
Make Functor a quantified superclass of Bifunctor.

See https://github.com/haskell/core-libraries-committee/issues/91 for
discussion.

This change relates Bifunctor with Functor by requiring second = fmap.
Moreover this change is a step towards unblocking the major version bump
of bifunctors and profunctors to major version 6. This paves the way to
move the Profunctor class into base. For that Functor first similarly
becomes a superclass of Profunctor in the new major version 6.

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72cf4c5d by doyougnu at 2022-12-01T12:36:44-05:00
FastString: SAT bucket_match

Metric Decrease:
    MultiLayerModulesTH_OneShot

- - - - -
afc2540d by Simon Peyton Jones at 2022-12-01T12:37:20-05:00
Add a missing varToCoreExpr in etaBodyForJoinPoint

This subtle bug showed up when compiling a library with 9.4.
See #22491.  The bug is present in master, but it is hard to
trigger; the new regression test T22491 fails in 9.4.

The fix was easy: just add a missing varToCoreExpr in
etaBodyForJoinPoint.

The fix is definitely right though!

I also did some other minor refatoring:
* Moved the preInlineUnconditionally test in simplExprF1 to
  before the call to joinPointBinding_maybe, to avoid fruitless
  eta-expansion.
* Added a boolean from_lam flag to simplNonRecE, to avoid two
  fruitless tests, and commented it a bit better.

These refactorings seem to save 0.1% on compile-time allocation in
perf/compiler; with a max saving of 1.4% in T9961

Metric Decrease:
    T9961

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81eeec7f by M Farkas-Dyck at 2022-12-01T12:37:56-05:00
CI: Forbid the fully static build on Alpine to fail.

To do so, we mark some tests broken in this configuration.

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c5d1bf29 by Bryan Richter at 2022-12-01T12:37:56-05:00
CI: Remove ARMv7 jobs

These jobs fail (and are allowed to fail) nearly every time.

Soon they won't even be able to run at all, as we won't currently have
runners that can run them.

Fixing the latter problem is tracked in #22409.

I went ahead and removed all settings and configurations.

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d82992fd by Bryan Richter at 2022-12-01T12:37:56-05:00
CI: Fix CI lint

Failure was introduced by conflicting changes to gen_ci.hs that did
*not* trigger git conflicts.

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ce126993 by Simon Peyton Jones at 2022-12-02T01:22:12-05:00
Refactor TyCon to have a top-level product

This patch changes the representation of TyCon so that it has
a top-level product type, with a field that gives the details
(newtype, type family etc), #22458.

Not much change in allocation, but execution seems to be a bit
faster.

Includes a change to the haddock submodule to adjust for API changes.

- - - - -
74c767df by Matthew Pickering at 2022-12-02T01:22:48-05:00
ApplicativeDo: Set pattern location before running exhaustiveness checker

This improves the error messages of the exhaustiveness checker when
checking statements which have been moved around with ApplicativeDo.

Before:

Test.hs:2:3: warning: [GHC-62161] [-Wincomplete-uni-patterns]
    Pattern match(es) are non-exhaustive
    In a pattern binding:
        Patterns of type ‘Maybe ()’ not matched: Nothing
  |
2 |   let x = ()
  |   ^^^^^^^^^^

After:

Test.hs:4:3: warning: [GHC-62161] [-Wincomplete-uni-patterns]
    Pattern match(es) are non-exhaustive
    In a pattern binding:
        Patterns of type ‘Maybe ()’ not matched: Nothing
  |
4 |   ~(Just res1) <- seq x (pure $ Nothing @())
  |

Fixes #22483

- - - - -
85ecc1a0 by Matthew Pickering at 2022-12-02T19:46:43-05:00
Add special case for :Main module in `GHC.IfaceToCore.mk_top_id`

See Note [Root-main Id]

The `:Main` special binding is actually defined in the current module
(hence don't go looking for it externally) but the module name is rOOT_MAIN
rather than the current module so we need this special case.

There was already some similar logic in `GHC.Rename.Env` for
External Core, but now the "External Core" is in interface files it
needs to be moved here instead.

Fixes #22405

- - - - -
108c319f by Krzysztof Gogolewski at 2022-12-02T19:47:18-05:00
Fix linearity checking in Lint

Lint was not able to see that x*y <= x*y, because this inequality
was decomposed to x <= x*y && y <= x*y, but there was no rule
to see that x <= x*y.

Fixes #22546.

- - - - -
bb674262 by Bryan Richter at 2022-12-03T04:38:46-05:00
Mark T16916 fragile

See https://gitlab.haskell.org/ghc/ghc/-/issues/16966

- - - - -
5d267d46 by Vladislav Zavialov at 2022-12-03T04:39:22-05:00
Refactor: FreshOrReuse instead of addTyClTyVarBinds

This is a refactoring that should have no effect on observable behavior.

Prior to this change, GHC.HsToCore.Quote contained a few closely related
functions to process type variable bindings: addSimpleTyVarBinds,
addHsTyVarBinds, addQTyVarBinds, and addTyClTyVarBinds.

We can classify them by their input type and name generation strategy:

                              Fresh names only    Reuse bound names
                          +---------------------+-------------------+
                   [Name] | addSimpleTyVarBinds |                   |
[LHsTyVarBndr flag GhcRn] |     addHsTyVarBinds |                   |
        LHsQTyVars GhcRn  |      addQTyVarBinds | addTyClTyVarBinds |
                          +---------------------+-------------------+

Note how two functions are missing. Because of this omission, there were
two places where a LHsQTyVars value was constructed just to be able to pass it
to addTyClTyVarBinds:

1. mk_qtvs in addHsOuterFamEqnTyVarBinds    -- bad
2. mkHsQTvs in repFamilyDecl                -- bad

This prevented me from making other changes to LHsQTyVars, so the main
goal of this refactoring is to get rid of those workarounds.

The most direct solution would be to define the missing functions.
But that would lead to a certain amount of code duplication. To avoid
code duplication, I factored out the name generation strategy into a
function parameter:

	data FreshOrReuse
	  = FreshNamesOnly
	  | ReuseBoundNames

	addSimpleTyVarBinds :: FreshOrReuse -> ...
	addHsTyVarBinds     :: FreshOrReuse -> ...
	addQTyVarBinds      :: FreshOrReuse -> ...

- - - - -
c189b831 by Vladislav Zavialov at 2022-12-03T04:39:22-05:00
addHsOuterFamEqnTyVarBinds: use FreshNamesOnly for explicit binders

Consider this example:

	[d| instance forall a. C [a] where
	      type forall b. G [a] b = Proxy b |]

When we process "forall b." in the associated type instance, it is
unambiguously the binding site for "b" and we want a fresh name for it.
Therefore, FreshNamesOnly is more fitting than ReuseBoundNames.
This should not have any observable effect but it avoids pointless
lookups in the MetaEnv.

- - - - -
42512264 by Ross Paterson at 2022-12-03T10:32:45+00:00
Handle type data declarations in Template Haskell quotations and splices (fixes #22500)

This adds a TypeDataD constructor to the Template Haskell Dec type,
and ensures that the constructors it contains go in the TyCls namespace.

- - - - -
1a767fa3 by Vladislav Zavialov at 2022-12-05T05:18:50-05:00
Add BufSpan to EpaLocation (#22319, #22558)

The key part of this patch is the change to mkTokenLocation:

	- mkTokenLocation (RealSrcSpan r _)  = TokenLoc (EpaSpan r)
	+ mkTokenLocation (RealSrcSpan r mb) = TokenLoc (EpaSpan r mb)

mkTokenLocation used to discard the BufSpan, but now it is saved and can
be retrieved from LHsToken or LHsUniToken.

This is made possible by the following change to EpaLocation:

	- data EpaLocation = EpaSpan !RealSrcSpan
	+ data EpaLocation = EpaSpan !RealSrcSpan !(Strict.Maybe BufSpan)
	                   | ...

The end goal is to make use of the BufSpan in Parser/PostProcess/Haddock.

- - - - -
cd31acad by sheaf at 2022-12-06T15:45:58-05:00
Hadrian: fix ghcDebugAssertions off-by-one error

Commit 6b2f7ffe changed the logic that decided whether to enable debug
assertions. However, it had an off-by-one error, as the stage parameter
to the function inconsistently referred to the stage of the compiler
being used to build or the stage of the compiler we are building.

This patch makes it consistent. Now the parameter always refers to the
the compiler which is being built.

In particular, this patch re-enables
assertions in the stage 2 compiler when building with devel2 flavour,
and disables assertions in the stage 2 compiler when building with
validate flavour.

Some extra performance tests are now run in the "validate" jobs because
the stage2 compiler no longer contains assertions.

-------------------------
Metric Decrease:
    CoOpt_Singletons
    MultiComponentModules
    MultiComponentModulesRecomp
    MultiLayerModulesTH_OneShot
    T11374
    T12227
    T12234
    T13253-spj
    T13701
    T14683
    T14697
    T15703
    T17096
    T17516
    T18304
    T18478
    T18923
    T5030
    T9872b
    TcPlugin_RewritePerf
Metric Increase:
    MultiComponentModules
    MultiComponentModulesRecomp
    MultiLayerModules
    MultiLayerModulesRecomp
    MultiLayerModulesTH_Make
    T13386
    T13719
    T3294
    T9233
    T9675
    parsing001
-------------------------

- - - - -
21d66db1 by mrkun at 2022-12-06T15:46:38-05:00
Push DynFlags out of runInstallNameTool

- - - - -
aaaaa79b by mrkun at 2022-12-06T15:46:38-05:00
Push DynFlags out of askOtool

- - - - -
4e28f49e by mrkun at 2022-12-06T15:46:38-05:00
Push DynFlags out of runInjectRPaths

- - - - -
a7422580 by mrkun at 2022-12-06T15:46:38-05:00
Push DynFlags out of Linker.MacOS

- - - - -
e902d771 by Matthew Craven at 2022-12-08T08:30:23-05:00
Fix bounds-checking buglet in Data.Array.Byte

...another manifestation of #20851 which
I unfortunately missed in my first pass.

- - - - -
8d36c0c6 by Gergő Érdi at 2022-12-08T08:31:03-05:00
Remove copy-pasted definitions of `graphFromEdgedVertices*`

- - - - -
c5d8ed3a by Gergő Érdi at 2022-12-08T08:31:03-05:00
Add version of `reachableGraph` that avoids loop for cyclic inputs
by building its result connected component by component

Fixes #22512

- - - - -
90cd5396 by Krzysztof Gogolewski at 2022-12-08T08:31:39-05:00
Mark Type.Reflection.Unsafe as Unsafe

This module can be used to construct ill-formed TypeReps, so it should
be Unsafe.

- - - - -
2057c77d by Ian-Woo Kim at 2022-12-08T08:32:19-05:00
Truncate eventlog event for large payload (#20221)

RTS eventlog events for postCapsetVecEvent are truncated if payload
is larger than EVENT_PAYLOAD_SIZE_MAX
Previously, postCapsetVecEvent records eventlog event with payload
of variable size larger than EVENT_PAYLOAD_SIZE_MAX (2^16) without
any validation, resulting in corrupted data.
For example, this happens when a Haskell binary is invoked with very
long command line arguments exceeding 2^16 bytes (see #20221).
Now we check the size of accumulated payload messages incrementally,
and truncate the message just before the payload size exceeds
EVENT_PAYLOAD_SIZE_MAX. RTS will warn the user with a message showing
how many arguments are truncated.

- - - - -
9ec76f61 by Cheng Shao at 2022-12-08T08:32:59-05:00
hadrian: don't add debug info to non-debug ways of rts

Hadrian used to pass -g when building all ways of rts. It makes output
binaries larger (especially so for wasm backend), and isn't needed by
most users out there, so this patch removes that flag. In case the
debug info is desired, we still pass -g3 when building the debug way,
and there's also the debug_info flavour transformer which ensures -g3
is passed for all rts ways.

- - - - -
7658cdd4 by Krzysztof Gogolewski at 2022-12-08T08:33:36-05:00
Restore show (typeRep @[]) == "[]"

The Show instance for TypeRep [] has changed in 9.5 to output "List"
because the name of the type constructor changed.
This seems to be accidental and is inconsistent with TypeReps of saturated
lists, which are printed as e.g. "[Int]".
For now, I'm restoring the old behavior; in the future,
maybe we should show TypeReps without puns (List, Tuple, Type).

- - - - -
216deefd by Matthew Pickering at 2022-12-08T22:45:27-05:00
Add test for #22162

- - - - -
5d0a311f by Matthew Pickering at 2022-12-08T22:45:27-05:00
ci: Add job to test interface file determinism guarantees

In this job we can run on every commit we add a test which builds the
Cabal library twice and checks that the ABI hash and interface hash is
stable across the two builds.

* We run the test 20 times to try to weed out any race conditions due to
  `-j`
* We run the builds in different temporary directories to try to weed
  out anything related to build directory affecting ABI or interface
  file hash.

Fixes #22180

- - - - -
0a76d7d4 by Matthew Pickering at 2022-12-08T22:45:27-05:00
ci: Add job for testing interface stability across builds

The idea is that both the bindists should product libraries with the
same ABI and interface hash.
So the job checks with ghc-pkg to make sure the computed ABI
is the same.

In future this job can be extended to check for the other facets of
interface determinism.

Fixes #22180

- - - - -
74c9bf91 by Matthew Pickering at 2022-12-08T22:45:27-05:00
backpack: Be more careful when adding together ImportAvails

There was some code in the signature merging logic which added together
the ImportAvails of the signature and the signature which was merged
into it. This had the side-effect of making the merged signature depend
on the signature (via a normal module dependency). The intention was to
propagate orphan instances through the merge but this also messed up
recompilation logic because we shouldn't be attempting to load B.hi when
mergeing it.

The fix is to just combine the part of ImportAvails that we intended to
(transitive info, orphan instances and type family instances) rather
than the whole thing.

- - - - -
d122e022 by Matthew Pickering at 2022-12-08T22:45:27-05:00
Fix mk_mod_usage_info if the interface file is not already loaded

In #22217 it was observed that the order modules are compiled in affects
the contents of an interface file. This was because a module dependended
on another module indirectly, via a re-export but the interface file for
this module was never loaded because the symbol was never used in the
file.

If we decide that we depend on a module then we jolly well ought to
record this fact in the interface file! Otherwise it could lead to very
subtle recompilation bugs if the dependency is not tracked and the
module is updated.

Therefore the best thing to do is just to make sure the file is loaded
by calling the `loadSysInterface` function.  This first checks the
caches (like we did before) but then actually goes to find the interface
on disk if it wasn't loaded.

Fixes #22217

- - - - -
ea25088d by lrzlin at 2022-12-08T22:46:06-05:00
Add initial support for LoongArch Architecture.

- - - - -
9eb9d2f4 by Bodigrim at 2022-12-08T22:46:47-05:00
Update submodule mtl to 2.3.1, parsec to 3.1.15.1, haddock and Cabal to HEAD

- - - - -
08d8fe2a by Bodigrim at 2022-12-08T22:46:47-05:00
Allow mtl-2.3 in hadrian

- - - - -
3807a46c by Bodigrim at 2022-12-08T22:46:47-05:00
Support mtl-2.3 in check-exact

- - - - -
ef702a18 by Bodigrim at 2022-12-08T22:46:47-05:00
Fix tests

- - - - -
3144e8ff by Sebastian Graf at 2022-12-08T22:47:22-05:00
Make (^) INLINE (#22324)

So that we get to cancel away the allocation for the lazily used base.

We can move `powImpl` (which *is* strict in the base) to the top-level
so that we don't duplicate too much code and move the SPECIALISATION
pragmas onto `powImpl`.

The net effect of this change is that `(^)` plays along much better with
inlining thresholds and loopification (#22227), for example in `x2n1`.

Fixes #22324.

- - - - -
1d3a8b8e by Matthew Pickering at 2022-12-08T22:47:59-05:00
Typeable: Fix module locations of some definitions in GHC.Types

There was some confusion in Data.Typeable about which module certain
wired-in things were defined in. Just because something is wired-in
doesn't mean it comes from GHC.Prim, in particular things like LiftedRep
and RuntimeRep are defined in GHC.Types and that's the end of the story.

Things like Int#, Float# etc are defined in GHC.Prim as they have no
Haskell definition site at all so we need to generate type
representations for them (which live in GHC.Types).

Fixes #22510

- - - - -
0f7588b5 by Sebastian Graf at 2022-12-08T22:48:34-05:00
Make `drop` and `dropWhile` fuse (#18964)

I copied the fusion framework we have in place for `take`.
T18964 asserts that we regress neither when fusion fires nor when it doesn't.

Fixes #18964.

- - - - -
26e71562 by Sebastian Graf at 2022-12-08T22:49:10-05:00
Do not strictify a DFun's parameter dictionaries (#22549)

... thus fixing #22549.

The details are in the refurbished and no longer dead
`Note [Do not strictify a DFun's parameter dictionaries]`.

There's a regression test in T22549.

- - - - -
36093407 by John Ericson at 2022-12-08T22:49:45-05:00
Delete `rts/package.conf.in`

It is a relic of the Make build system. The RTS now uses a
`package.conf` file generated the usual way by Cabal.

- - - - -
b0cc2fcf by Krzysztof Gogolewski at 2022-12-08T22:50:21-05:00
Fixes around primitive literals

* The SourceText of primitive characters 'a'# did not include
  the #, unlike for other primitive literals 1#, 1##, 1.0#, 1.0##, "a"#.
  We can now remove the function pp_st_suffix, which was a hack
  to add the # back.
* Negative primitive literals shouldn't use parentheses, as described in
  Note [Printing of literals in Core]. Added a testcase to T14681.

- - - - -
aacf616d by Bryan Richter at 2022-12-08T22:50:56-05:00
testsuite: Mark conc024 fragile on Windows

- - - - -
ed239a24 by Ryan Scott at 2022-12-09T09:42:16-05:00
Document TH splices' interaction with INCOHERENT instances

Top-level declaration splices can having surprising interactions with
`INCOHERENT` instances, as observed in #22492. This patch
resolves #22492 by documenting this strange interaction in the GHC User's
Guide.

[ci skip]

- - - - -
1023b432 by Mike Pilgrem at 2022-12-09T09:42:56-05:00
Fix #22300 Document GHC's extensions to valid whitespace

- - - - -
79b0cec0 by Luite Stegeman at 2022-12-09T09:43:38-05:00
Add support for environments that don't have setImmediate

- - - - -
5b007ec5 by Luite Stegeman at 2022-12-09T09:43:38-05:00
Fix bound thread status

- - - - -
65335d10 by Matthew Pickering at 2022-12-09T20:15:45-05:00
Update containers submodule

This contains a fix necessary for the multi-repl to work on GHC's code
base where we try to load containers and template-haskell into the same
session.

- - - - -
4937c0bb by Matthew Pickering at 2022-12-09T20:15:45-05:00
hadrian-multi: Put interface files in separate directories

Before we were putting all the interface files in the same directory
which was leading to collisions if the files were called the same thing.

- - - - -
8acb5b7b by Matthew Pickering at 2022-12-09T20:15:45-05:00
hadrian-toolargs: Add filepath to allowed repl targets

- - - - -
5949d927 by Matthew Pickering at 2022-12-09T20:15:45-05:00
driver: Set correct UnitId when rehydrating modules

We were not setting the UnitId before rehydrating modules which just led
to us attempting to find things in the wrong HPT. The test for this is
the hadrian-multi command (which is now added as a CI job).

Fixes #22222

- - - - -
ab06c0f0 by Matthew Pickering at 2022-12-09T20:15:45-05:00
ci: Add job to test hadrian-multi command

I am not sure this job is good because it requires booting HEAD with
HEAD, but it should be fine.

- - - - -
fac3e568 by Matthew Pickering at 2022-12-09T20:16:20-05:00
hadrian: Update bootstrap plans to 9.2.* series and 9.4.* series.

This updates the build plans for the most recent compiler versions, as
well as fixing the hadrian-bootstrap-gen script to a specific GHC
version.

- - - - -
195b08b4 by Matthew Pickering at 2022-12-09T20:16:20-05:00
ci: Bump boot images to use ghc-9.4.3

Also updates the bootstrap jobs to test booting 9.2 and 9.4.

- - - - -
c658c580 by Matthew Pickering at 2022-12-09T20:16:20-05:00
hlint: Removed redundant UnboxedSums pragmas

UnboxedSums is quite confusingly implied by UnboxedTuples, alas, just
the way it is.

See #22485

- - - - -
b3e98a92 by Oleg Grenrus at 2022-12-11T12:26:17-05:00
Add heqT, a kind-heterogeneous variant of heq

CLC proposal https://github.com/haskell/core-libraries-committee/issues/99

- - - - -
bfd7c1e6 by Bodigrim at 2022-12-11T12:26:55-05:00
Document that Bifunctor instances for tuples are lawful only up to laziness

- - - - -
5d1a1881 by Bryan Richter at 2022-12-12T16:22:36-05:00
Mark T21336a fragile

- - - - -
c30accc2 by Matthew Pickering at 2022-12-12T16:23:11-05:00
Add test for #21476

This issues seems to have been fixed since the ticket was made, so let's
add a test and move on.

Fixes #21476

- - - - -
e9d74a3e by Sebastian Graf at 2022-12-13T22:18:39-05:00
Respect -XStrict in the pattern-match checker (#21761)

We were missing a call to `decideBangHood` in the pattern-match checker.
There is another call in `matchWrapper.mk_eqn_info` which seems redundant
but really is not; see `Note [Desugaring -XStrict matches in Pmc]`.

Fixes #21761.

- - - - -
884790e2 by Gergő Érdi at 2022-12-13T22:19:14-05:00
Fix loop in the interface representation of some `Unfolding` fields

As discovered in #22272, dehydration of the unfolding info of a
recursive definition used to involve a traversal of the definition
itself, which in turn involves traversing the unfolding info. Hence,
a loop.

Instead, we now store enough data in the interface that we can produce
the unfolding info without this traversal. See Note [Tying the 'CoreUnfolding' knot]
for details.

Fixes #22272

Co-authored-by: Simon Peyton Jones <simon.peytonjones at gmail.com>

- - - - -
9f301189 by Alan Zimmerman at 2022-12-13T22:19:50-05:00
EPA: When splitting out header comments, keep ones for first decl

Any comments immediately preceding the first declaration are no longer
kept as header comments, but attach to the first declaration instead.

- - - - -
8b1f1b45 by Sylvain Henry at 2022-12-13T22:20:28-05:00
JS: fix object file name comparison (#22578)

- - - - -
e9e161bb by Bryan Richter at 2022-12-13T22:21:03-05:00
configure: Bump min bootstrap GHC version to 9.2

- - - - -
75855643 by Ben Gamari at 2022-12-15T03:54:02-05:00
hadrian: Don't enable TSAN in stage0 build

- - - - -
da7b51d8 by Ben Gamari at 2022-12-15T03:54:02-05:00
cmm: Introduce blockConcat

- - - - -
34f6b09c by Ben Gamari at 2022-12-15T03:54:02-05:00
cmm: Introduce MemoryOrderings

- - - - -
43beaa7b by Ben Gamari at 2022-12-15T03:54:02-05:00
llvm: Respect memory specified orderings

- - - - -
8faf74fc by Ben Gamari at 2022-12-15T03:54:02-05:00
Codegen/x86: Eliminate barrier for relaxed accesses

- - - - -
6cc3944a by Ben Gamari at 2022-12-15T03:54:02-05:00
cmm/Parser: Reduce some repetition

- - - - -
6c9862c4 by Ben Gamari at 2022-12-15T03:54:02-05:00
cmm/Parser: Add syntax for ordered loads and stores

- - - - -
748490d2 by Ben Gamari at 2022-12-15T03:54:02-05:00
cmm/Parser: Atomic load syntax

Originally I had thought I would just use the `prim` call syntax instead
of introducing new syntax for atomic loads. However, it turns out that
`prim` call syntax tends to make things quite unreadable. This new
syntax seems quite natural.

- - - - -
28c6781a by Ben Gamari at 2022-12-15T03:54:02-05:00
codeGen: Introduce ThreadSanitizer instrumentation

This introduces a new Cmm pass which instruments the program with
ThreadSanitizer annotations, allowing full tracking of mutator memory
accesses via TSAN.

- - - - -
d97aa311 by Ben Gamari at 2022-12-15T03:54:02-05:00
Hadrian: Drop TSAN_ENABLED define from flavour

This is redundant since the TSANUtils.h already defines it.

- - - - -
86974ef1 by Ben Gamari at 2022-12-15T03:54:02-05:00
hadrian: Enable Cmm instrumentation in TSAN flavour

- - - - -
93723290 by Ben Gamari at 2022-12-15T03:54:02-05:00
rts: Ensure that global regs are never passed as fun call args

This is in general unsafe as they may be clobbered if they are mapped to
caller-saved machine registers. See Note [Register parameter passing].

- - - - -
2eb0fb87 by Matthew Pickering at 2022-12-15T03:54:39-05:00
Package Imports: Get candidate packages also from re-exported modules

Previously we were just looking at the direct imports to try and work
out what a package qualifier could apply to but #22333 pointed out we
also needed to look for reexported modules.

Fixes #22333

- - - - -
552b7908 by Ben Gamari at 2022-12-15T03:55:15-05:00
compiler: Ensure that MutVar operations have necessary barriers

Here we add acquire and release barriers in readMutVar# and
writeMutVar#, which are necessary for soundness.

Fixes #22468.

- - - - -
933d61a4 by Simon Peyton Jones at 2022-12-15T03:55:51-05:00
Fix bogus test in Lint

The Lint check for branch compatiblity within an axiom, in
GHC.Core.Lint.compatible_branches was subtly different to the
check made when contructing an axiom, in
GHC.Core.FamInstEnv.compatibleBranches.

The latter is correct, so I killed the former and am now using the
latter.

On the way I did some improvements to pretty-printing and documentation.

- - - - -
03ed0b95 by Ryan Scott at 2022-12-15T03:56:26-05:00
checkValidInst: Don't expand synonyms when splitting sigma types

Previously, the `checkValidInst` function (used when checking that an instance
declaration is headed by an actual type class, not a type synonym) was using
`tcSplitSigmaTy` to split apart the `forall`s and instance context. This is
incorrect, however, as `tcSplitSigmaTy` expands type synonyms, which can cause
instances headed by quantified constraint type synonyms to be accepted
erroneously.

This patch introduces `splitInstTyForValidity`, a variant of `tcSplitSigmaTy`
specialized for validity checking that does _not_ expand type synonyms, and
uses it in `checkValidInst`.

Fixes #22570.

- - - - -
ed056bc3 by Ben Gamari at 2022-12-16T16:12:44-05:00
rts/Messages: Refactor

This doesn't change behavior but makes the code a bit easier to follow.

- - - - -
7356f8e0 by Ben Gamari at 2022-12-16T16:12:44-05:00
rts/ThreadPaused: Ordering fixes

- - - - -
914f0025 by Ben Gamari at 2022-12-16T16:12:44-05:00
eventlog: Silence spurious data race

- - - - -
fbc84244 by Ben Gamari at 2022-12-16T16:12:44-05:00
Introduce SET_INFO_RELEASE for Cmm

- - - - -
821b5472 by Ben Gamari at 2022-12-16T16:12:44-05:00
rts: Use fences instead of explicit barriers

- - - - -
2228c999 by Ben Gamari at 2022-12-16T16:12:44-05:00
rts/stm: Fix memory ordering in readTVarIO#

See #22421.

- - - - -
99269b9f by Ben Gamari at 2022-12-16T16:12:44-05:00
Improve heap memory barrier Note

Also introduce MUT_FIELD marker in Closures.h to document mutable
fields.

- - - - -
70999283 by Ben Gamari at 2022-12-16T16:12:44-05:00
rts: Introduce getNumCapabilities

And ensure accesses to n_capabilities are atomic (although with relaxed
ordering). This is necessary as RTS API callers may concurrently call
into the RTS without holding a capability.

- - - - -
98689f77 by Ben Gamari at 2022-12-16T16:12:44-05:00
ghc: Fix data race in dump file handling

Previously the dump filename cache would use a non-atomic update which
could potentially result in lost dump contents. Note that this is still
a bit racy since the first writer may lag behind a later appending
writer.

- - - - -
605d9547 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Always use atomics for context_switch and interrupt

Since these are modified by the timer handler.

- - - - -
86f20258 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts/Timer: Always use atomic operations

As noted in #22447, the existence of the pthread-based ITimer
implementation means that we cannot assume that the program is
single-threaded.

- - - - -
f8e901dc by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Encapsulate recent_activity access

This makes it easier to ensure that it is accessed using the necessary
atomic operations.

- - - - -
e0affaa9 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Encapsulate access to capabilities array

- - - - -
7ca683e4 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Encapsulate sched_state

- - - - -
1cf13bd0 by Ben Gamari at 2022-12-16T16:12:45-05:00
PrimOps: Fix benign MutVar race

Relaxed ordering is fine here since the later CAS implies a release.

- - - - -
3d2a7e08 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Style fix

- - - - -
82c62074 by Ben Gamari at 2022-12-16T16:12:45-05:00
compiler: Use release store in eager blackholing

- - - - -
eb1a0136 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Fix ordering of makeStableName

- - - - -
ad0e260a by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Use ordered accesses instead of explicit barriers

- - - - -
a3eccf06 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Statically allocate capabilities

This is a rather simplistic way of solving #17289.

- - - - -
287fa3fb by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Ensure that all accesses to pending_sync are atomic

- - - - -
351eae58 by Ben Gamari at 2022-12-16T16:12:45-05:00
rts: Note race with wakeBlockingQueue

- - - - -
5acf33dd by Bodigrim at 2022-12-16T16:13:22-05:00
Bump submodule directory to 1.3.8.0 and hpc to HEAD

- - - - -
0dd95421 by Bodigrim at 2022-12-16T16:13:22-05:00
Accept allocations increase on Windows

This is because of `filepath-1.4.100.0` and AFPP, causing increasing round-trips
between lists and ByteArray. See #22625 for discussion.

Metric Increase:
    MultiComponentModules
    MultiComponentModulesRecomp
    MultiLayerModules
    MultiLayerModulesRecomp
    T10421
    T10547
    T12150
    T12227
    T12234
    T12425
    T13035
    T13253
    T13253-spj
    T13701
    T13719
    T15703
    T16875
    T18140
    T18282
    T18304
    T18698a
    T18698b
    T18923
    T20049
    T21839c
    T21839r
    T5837
    T6048
    T9198
    T9961
    TcPlugin_RewritePerf
    hard_hole_fits

- - - - -
ef9ac9d2 by Cheng Shao at 2022-12-16T16:13:59-05:00
testsuite: Mark T9405 as fragile instead of broken on Windows

It's starting to pass again, and the unexpected pass blocks CI.

- - - - -
1f3abd85 by Cheng Shao at 2022-12-16T21:16:28+00:00
compiler: remove obsolete commented code in wasm NCG

It was just a temporary hack to workaround a bug in the relooper, that
bug has been fixed long before the wasm backend is merged.

- - - - -
e3104eab by Cheng Shao at 2022-12-16T21:16:28+00:00
compiler: add missing export list of GHC.CmmToAsm.Wasm.FromCmm

Also removes some unreachable code here.

- - - - -
1c6930bf by Cheng Shao at 2022-12-16T21:16:28+00:00
compiler: change fallback function signature to Cmm function signature in wasm NCG

In the wasm NCG, when handling a `CLabel` of undefined function
without knowing its function signature, we used to fallback to `() ->
()` which is accepted by `wasm-ld`. This patch changes it to the
signature of Cmm functions, which equally works, but would be required
when we emit tail call instructions.

- - - - -
8a81d9d9 by Cheng Shao at 2022-12-16T21:16:28+00:00
compiler: add optional tail-call support in wasm NCG

When the `-mtail-call` clang flag is passed at configure time, wasm
tail-call extension is enabled, and the wasm NCG will emit
`return_call`/`return_call_indirect` instructions to take advantage of
it and avoid the `StgRun` trampoline overhead.

Closes #22461.

- - - - -
d1431cc0 by Cheng Shao at 2022-12-17T08:07:15-05:00
base: add missing autoconf checks for waitpid/umask

These are not present in wasi-libc. Required for fixing #22589

- - - - -
da3f1e91 by Cheng Shao at 2022-12-17T08:07:51-05:00
compiler: make .wasm the default executable extension on wasm32

Following convention as in other wasm toolchains. Fixes #22594.

- - - - -
ad21f4ef by Cheng Shao at 2022-12-17T08:07:51-05:00
ci: support hello.wasm in ci.sh cross testing logic

- - - - -
6fe2d778 by amesgen at 2022-12-18T19:33:49-05:00
Correct `exitWith` Haddocks

The `IOError`-specific `catch` in the Prelude is long gone.

- - - - -
b3eacd64 by Ben Gamari at 2022-12-18T19:34:24-05:00
rts: Drop racy assertion

0e274c39bf836d5bb846f5fa08649c75f85326ac added an assertion in
`dirty_MUT_VAR` checking that the MUT_VAR being dirtied was clean.
However, this isn't necessarily the case since another thread may have
raced us to dirty the object.

- - - - -
761c1f49 by Ben Gamari at 2022-12-18T19:35:00-05:00
rts/libdw: Silence uninitialized usage warnings

As noted in #22538, previously some GCC versions warned that various
locals in Libdw.c may be used uninitialized. Although this wasn't
strictly true (since they were initialized in an inline assembler block)
we fix this by providing explicit empty initializers.

Fixes #22538
- - - - -
5e047eff by Matthew Pickering at 2022-12-20T15:12:04+00:00
testsuite: Mark T16392 as fragile on windows

See #22649

- - - - -
703a4665 by M Farkas-Dyck at 2022-12-20T21:14:46-05:00
Scrub some partiality in `GHC.Cmm.Info.Build`: `doSRTs` takes a `[(CAFSet, CmmDecl)]` but truly wants a `[(CAFSet, CmmStatics)]`.

- - - - -
9736ab74 by Matthew Pickering at 2022-12-20T21:15:22-05:00
packaging: Fix upload_ghc_libs.py script

This change reflects the changes where .cabal files are now generated by
hadrian rather than ./configure.

Fixes #22518

- - - - -
7c6de18d by Ben Gamari at 2022-12-20T21:15:57-05:00
configure: Drop uses of AC_PROG_CC_C99

As noted in #22566, this macro is deprecated as of autoconf-2.70
`AC_PROG_CC` now sets `ac_cv_prog_cc_c99` itself.

Closes #22566.

- - - - -
36c5d98e by Ben Gamari at 2022-12-20T21:15:57-05:00
configure: Use AS_HELP_STRING instead of AC_HELP_STRING

The latter has been deprecated.

See #22566.

- - - - -
befe6ff8 by Bodigrim at 2022-12-20T21:16:37-05:00
GHCi.UI: fix various usages of head and tail

- - - - -
666d0ba7 by Bodigrim at 2022-12-20T21:16:37-05:00
GHCi.UI: avoid head and tail in parseCallEscape and around

- - - - -
5d96fd50 by Bodigrim at 2022-12-20T21:16:37-05:00
Make GHC.Driver.Main.hscTcRnLookupRdrName to return NonEmpty

- - - - -
3ce2ab94 by Bodigrim at 2022-12-21T06:17:56-05:00
Allow transformers-0.6 in ghc, ghci, ghc-bin and hadrian

- - - - -
954de93a by Bodigrim at 2022-12-21T06:17:56-05:00
Update submodule haskeline to HEAD (to allow transformers-0.6)

- - - - -
cefbeec3 by Bodigrim at 2022-12-21T06:17:56-05:00
Update submodule transformers to 0.6.0.4

- - - - -
b4730b62 by Bodigrim at 2022-12-21T06:17:56-05:00
Fix tests

T13253 imports MonadTrans, which acquired a quantified constraint in transformers-0.6, thus increase in allocations

Metric Increase:
    T13253

- - - - -
0be75261 by Simon Peyton Jones at 2022-12-21T06:18:32-05:00
Abstract over the right free vars

Fix #22459, in two ways:

(1) Make the Specialiser not create a bogus specialisation if
    it is presented by strangely polymorphic dictionary.
    See Note [Weird special case in SpecDict] in
    GHC.Core.Opt.Specialise

(2) Be more careful in abstractFloats
    See Note [Which type variables to abstract over]
    in GHC.Core.Opt.Simplify.Utils.

So (2) stops creating the excessively polymorphic dictionary in
abstractFloats, while (1) stops crashing if some other pass should
nevertheless create a weirdly polymorphic dictionary.

- - - - -
df7bc6b3 by Ying-Ruei Liang (TheKK) at 2022-12-21T14:31:54-05:00
rts: explicitly store return value of ccall checkClosure to prevent type error (#22617)

- - - - -
e193e537 by Simon Peyton Jones at 2022-12-21T14:32:30-05:00
Fix shadowing lacuna in OccurAnal

Issue #22623 demonstrated another lacuna in the implementation
of wrinkle (BS3) in Note [The binder-swap substitution] in
the occurrence analyser.

I was failing to add TyVar lambda binders using
addInScope/addOneInScope and that led to a totally bogus binder-swap
transformation.

Very easy to fix.

- - - - -
3d55d8ab by Simon Peyton Jones at 2022-12-21T14:32:30-05:00
Fix an assertion check in addToEqualCtList

The old assertion saw that a constraint ct could rewrite itself
(of course it can) and complained (stupid).

Fixes #22645

- - - - -
ceb2e9b9 by Ben Gamari at 2022-12-21T15:26:08-05:00
configure: Bump version to 9.6

- - - - -
fb4d36c4 by Ben Gamari at 2022-12-21T15:27:49-05:00
base: Bump version to 4.18

Requires various submodule bumps.

- - - - -
93ee7e90 by Ben Gamari at 2022-12-21T15:27:49-05:00
ghc-boot: Fix bootstrapping

- - - - -
fc3a2232 by Ben Gamari at 2022-12-22T13:45:06-05:00
Bump GHC version to 9.7

- - - - -
914f7fe3 by Andreas Klebinger at 2022-12-22T23:36:10-05:00
Don't consider large byte arrays/compact regions pinned.

Workaround for #22255 which showed how treating large/compact regions
as pinned could cause segfaults.

- - - - -
32b32d7f by Matthew Pickering at 2022-12-22T23:36:46-05:00
hadrian bindist: Install manpages to share/man/man1/ghc.1

When the installation makefile was copied over the manpages were no
longer installed in the correct place. Now we install it into share/man/man1/ghc.1
as the make build system did.

Fixes #22371

- - - - -
b3ddf803 by Ben Gamari at 2022-12-22T23:37:23-05:00
rts: Drop paths from configure from cabal file

A long time ago we would rely on substitutions from the configure script
to inject paths of the include and library directories of libffi and
libdw. However, now these are instead handled inside Hadrian when
calling Cabal's `configure` (see the uses of `cabalExtraDirs` in
Hadrian's `Settings.Packages.packageArgs`).

While the occurrences in the cabal file were redundant, they did no
harm. However, since b5c714545abc5f75a1ffdcc39b4bfdc7cd5e64b4 they have
no longer been interpolated. @mpickering noticed the suspicious
uninterpolated occurrence of `@FFIIncludeDir@` in #22595,
prompting this commit to finally remove them.

- - - - -
b2c7523d by Ben Gamari at 2022-12-22T23:37:59-05:00
Bump libffi-tarballs submodule

We will now use libffi-3.4.4.

- - - - -
3699a554 by Alan Zimmerman at 2022-12-22T23:38:35-05:00
EPA: Make EOF position part of AnnsModule

Closes #20951
Closes #19697

- - - - -
99757ce8 by Sylvain Henry at 2022-12-22T23:39:13-05:00
JS: fix support for -outputdir (#22641)

The `-outputdir` option wasn't correctly handled with the JS backend
because the same code path was used to handle both objects produced by
the JS backend and foreign .js files. Now we clearly distinguish the
two in the pipeline, fixing the bug.

- - - - -
02ed7d78 by Simon Peyton Jones at 2022-12-22T23:39:49-05:00
Refactor mkRuntimeError

This patch fixes #22634.  Because we don't have TYPE/CONSTRAINT
polymorphism, we need two error functions rather than one.

I took the opportunity to rname runtimeError to impossibleError,
to line up with mkImpossibleExpr, and avoid confusion with the
genuine runtime-error-constructing functions.

- - - - -
35267f07 by Ben Gamari at 2022-12-22T23:40:32-05:00
base: Fix event manager shutdown race on non-Linux platforms

During shutdown it's possible that we will attempt to use a closed fd
to wakeup another capability's event manager. On the Linux eventfd path
we were careful to handle this. However on the non-Linux path we failed
to do so. Fix this.

- - - - -
317f45c1 by Simon Peyton Jones at 2022-12-22T23:41:07-05:00
Fix unifier bug: failing to decompose over-saturated type family

This simple patch fixes #22647

- - - - -
14b2e3d3 by Ben Gamari at 2022-12-22T23:41:42-05:00
rts/m32: Fix sanity checking

Previously we would attempt to clear pages which were marked as
read-only. Fix this.

- - - - -
16a1bcd1 by Matthew Pickering at 2022-12-23T09:15:24+00:00
ci: Move wasm pipelines into nightly rather than master

See #22664 for the changes which need to be made to bring one of these
back to the validate pipeline.

- - - - -
18d2acd2 by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Fix race in marking of blackholes

We must use an acquire-fence when marking to ensure that the indirectee
is visible.

- - - - -
11241efa by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Fix segment list races

- - - - -
602455c9 by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Use atomic when looking at bd->gen

Since it may have been mutated by a moving GC.

- - - - -
9d63b160 by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Eliminate race in bump_static_flag

To ensure that we don't race with a mutator entering a new CAF we take
the SM mutex before touching static_flag. The other option here would be
to instead modify newCAF to use a CAS but the present approach is a bit
safer.

- - - - -
26837523 by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Ensure that mutable fields have acquire barrier

- - - - -
8093264a by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Fix races in collector status tracking

Mark a number of accesses to do with tracking of the status of the
concurrent collection thread as atomic. No interesting races here,
merely necessary to satisfy TSAN.

- - - - -
387d4fcc by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Make segment state updates atomic

- - - - -
543cae00 by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Refactor update remembered set initialization

This avoids a lock inversion between the storage manager mutex and
the stable pointer table mutex by not dropping the SM_MUTEX in
nonmovingCollect. This requires quite a bit of rejiggering but it
does seem like a better strategy.

- - - - -
c9936718 by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Ensure that we aren't holding locks when closing them

TSAN complains about this sort of thing.

- - - - -
0cd31f7d by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Make bitmap accesses atomic

This is a benign race on any sensible hard since these are byte
accesses. Nevertheless, atomic accesses are necessary to satisfy
TSAN.

- - - - -
d3fe110a by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Fix benign race in update remembered set check

Relaxed load is fine here since we will take the lock before looking at
the list.

- - - - -
ab6cf893 by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Fix race in shortcutting

We must use an acquire load to read the info table pointer since if we
find an indirection we must be certain that we see the indirectee.

- - - - -
36c9f23c by Ben Gamari at 2022-12-23T19:09:30-05:00
nonmoving: Make free list counter accesses atomic

Since these may race with the allocator(s).

- - - - -
aebef31c by doyougnu at 2022-12-23T19:10:09-05:00
add GHC.Utils.Binary.foldGet' and use for Iface

A minor optimization to remove lazy IO and a lazy accumulator

strictify foldGet'

IFace.Binary: use strict foldGet'

remove superfluous bang

- - - - -
5eb357d9 by Ben Gamari at 2022-12-24T00:41:05-05:00
compiler: Ensure that GHC toolchain is first in search path

As noted in #22561, it is important that GHC's toolchain look
first for its own headers and libraries to ensure that the
system's are not found instead. If this happens things can
break in surprising ways (e.g. see #22561).

- - - - -
cbaebfb9 by Matthew Pickering at 2022-12-24T00:41:40-05:00
head.hackage: Use slow-validate bindist for linting jobs

This enables the SLOW_VALIDATE env var for the linting head.hackage
jobs, namely the jobs enabled manually, by the label or on the nightly
build now use the deb10-numa-slow-validate bindist which has assertions
enabled.

See #22623 for a ticket which was found by using this configuration
already!

The head.hackage jobs triggered by upstream CI are now thusly:

hackage-lint: Can be triggered on any MR, normal validate pipeline or nightly build.
              Runs head.hackage with -dlint and a slow-validate bindist

hackage-label-lint: Trigged on MRs with "user-facing" label, runs the slow-validate
                    head.hackage build with -dlint.

nightly-hackage-lint: Runs automatically on nightly pipelines with slow-validate + dlint config.

nightly-hackage-perf: Runs automaticaly on nightly pipelines with release build and eventlogging enabled.

release-hackage-lint: Runs automatically on release pipelines with -dlint on a release bindist.

- - - - -
f4850f36 by Matthew Pickering at 2022-12-24T00:41:40-05:00
ci: Don't run abi-test-nightly on release jobs

The test is not configured to get the correct dependencies for the
release pipelines (and indeed stops the release pipeline being run at
all)

- - - - -
c264b06b by Matthew Pickering at 2022-12-24T00:41:40-05:00
ci: Run head.hackage jobs on upstream-testing branch rather than master

This change allows less priviledged users to trigger head.hackage jobs
because less permissions are needed to trigger jobs on the
upstream-testing branch, which is not protected.

There is a CI job which updates upstream-testing each hour to the state
of the master branch so it should always be relatively up-to-date.

- - - - -
63b97430 by Ben Gamari at 2022-12-24T00:42:16-05:00
llvmGen: Fix relaxed ordering

Previously I used LLVM's `unordered` ordering for the C11 `relaxed`
ordering. However, this is wrong and should rather use the LLVM
`monotonic` ordering.

Fixes #22640
- - - - -
f42ba88f by Ben Gamari at 2022-12-24T00:42:16-05:00
gitlab-ci: Introduce aarch64-linux-llvm job

This nightly job will ensure that we don't break the LLVM backend on
AArch64/Linux by bootstrapping GHC.

This would have caught #22640.

- - - - -
6d62f6bf by Matthew Pickering at 2022-12-24T00:42:51-05:00
Store RdrName rather than OccName in Holes

In #20472 it was pointed out that you couldn't defer out of scope but
the implementation collapsed a RdrName into an OccName to stuff it into
a Hole. This leads to the error message for a deferred qualified name
dropping the qualification which affects the quality of the error
message.

This commit adds a bit more structure to a hole, so a hole can replace a
RdrName without losing information about what that RdrName was. This is
important when printing error messages.

I also added a test which checks the Template Haskell deferral of out of
scope qualified names works properly.

Fixes #22130

- - - - -
3c3060e4 by Richard Eisenberg at 2022-12-24T17:34:19+00:00
Drop support for kind constraints.

This implements proposal 547 and closes ticket #22298.
See the proposal and ticket for motivation.

Compiler perf improves a bit

Metrics: compile_time/bytes allocated
-------------------------------------
  CoOpt_Singletons(normal)   -2.4% GOOD
            T12545(normal)   +1.0%
            T13035(normal)  -13.5% GOOD
            T18478(normal)   +0.9%
            T9872d(normal)   -2.2% GOOD

                 geo. mean   -0.2%
                 minimum    -13.5%
                 maximum     +1.0%

Metric Decrease:
    CoOpt_Singletons
    T13035
    T9872d

- - - - -
6d7d4393 by Ben Gamari at 2022-12-24T21:09:56-05:00
hadrian: Ensure that linker scripts are used when merging objects

In #22527 @rui314 inadvertantly pointed out a glaring bug in Hadrian's
implementation of the object merging rules: unlike the old `make` build
system we utterly failed to pass the needed linker scripts. Fix this.

- - - - -
a5bd0eb8 by Bodigrim at 2022-12-24T21:10:34-05:00
Document infelicities of instance Ord Double and workarounds

- - - - -
62b9a7b2 by Zubin Duggal at 2023-01-03T12:22:11+00:00
Force the Docs structure to prevent leaks in GHCi with -haddock without -fwrite-interface

Involves adding many new NFData instances.

Without forcing Docs, references to the TcGblEnv for each module are retained
by the Docs structure. Usually these are forced when the ModIface is serialised
but not when we aren't writing the interface.

- - - - -
21bedd84 by Facundo Domínguez at 2023-01-03T23:27:30-05:00
Explain the auxiliary functions of permutations

- - - - -
32255d05 by Matthew Pickering at 2023-01-04T11:58:42+00:00
compiler: Add -f[no-]split-sections flags

Here we add a `-fsplit-sections` flag which may some day replace
`-split-sections`. This has the advantage of automatically providing a
`-fno-split-sections` flag, which is useful for our packaging because we
enable `-split-sections` by default but want to disable it in certain
configurations.

- - - - -
e640940c by Matthew Pickering at 2023-01-04T11:58:42+00:00
hadrian: Fix computation of tables_next_to_code for outOfTreeCompiler

This copy-pasto was introduced in de5fb3489f2a9bd6dc75d0cb8925a27fe9b9084b

- - - - -
15bee123 by Matthew Pickering at 2023-01-04T11:58:42+00:00
hadrian: Add test:all_deps to build just testsuite dependencies

Fixes #22534

- - - - -
fec6638e by Matthew Pickering at 2023-01-04T11:58:42+00:00
hadrian: Add no_split_sections tranformer

This transformer reverts the effect of `split_sections`, which we intend
to use for platforms which don't support split sections.

In order to achieve this we have to modify the implemntation of the
split_sections transformer to store whether we are enabling
split_sections directly in the `Flavour` definition. This is because
otherwise there's no convenient way to turn off split_sections due to
having to pass additional linker scripts when merging objects.

- - - - -
3dc05726 by Matthew Pickering at 2023-01-04T11:58:42+00:00
check-exact: Fix build with -Werror

- - - - -
53a6ae7a by Matthew Pickering at 2023-01-04T11:58:42+00:00
ci: Build all test dependencies with in-tree compiler

This means that these executables will honour flavour transformers such
as "werror".

Fixes #22555

- - - - -
32e264c1 by Matthew Pickering at 2023-01-04T11:58:42+00:00
hadrian: Document using GHC environment variable to select boot compiler

Fixes #22340

- - - - -
be9dd9b0 by Matthew Pickering at 2023-01-04T11:58:42+00:00
packaging: Build perf builds with -split-sections

In 8f71d958 the make build system was made to use split-sections on
linux systems but it appears this logic never made it to hadrian.
There is the split_sections flavour transformer but this doesn't appear
to be used for perf builds on linux.

This is disbled on deb9 and windows due to #21670

Closes #21135

- - - - -
00dc5106 by Matthew Pickering at 2023-01-04T14:32:45-05:00
sphinx: Use modern syntax for extlinks

This fixes the following build error:

```
  Command line: /opt/homebrew/opt/sphinx-doc/bin/sphinx-build -b man -d /private/tmp/extra-dir-55768274273/.doctrees-man -n -w /private/tmp/extra-dir-55768274273/.log docs/users_guide /private/tmp/extra-dir-55768274273
  ===> Command failed with error code: 2

  Exception occurred:
    File "/opt/homebrew/Cellar/sphinx-doc/6.0.0/libexec/lib/python3.11/site-packages/sphinx/ext/extlinks.py", line 101, in role
      title = caption % part
              ~~~~~~~~^~~~~~
  TypeError: not all arguments converted during string formatting
```

I tested on Sphinx-5.1.1 and Sphinx-6.0.0

Thanks for sterni for providing instructions about how to test using
sphinx-6.0.0.

Fixes #22690

- - - - -
541aedcd by Krzysztof Gogolewski at 2023-01-05T10:48:34-05:00
Misc cleanup

- Remove unused uniques and hs-boot declarations
- Fix types of seq and unsafeCoerce#
- Remove FastString/String roundtrip in JS
- Use TTG to enforce totality
- Remove enumeration in Heap/Inspect; the 'otherwise' clause
  serves the primitive types well.

- - - - -
22bb8998 by Alan Zimmerman at 2023-01-05T10:49:09-05:00
EPA: Do not collect comments from end of file

In Parser.y semis1 production triggers for the virtual semi at the end
of the file. This is detected by it being zero length.

In this case, do not extend the span being used to gather comments, so
any final comments are allocated at the module level instead.

- - - - -
9e077999 by Vladislav Zavialov at 2023-01-05T23:01:55-05:00
HsToken in TypeArg (#19623)

Updates the haddock submodule.

- - - - -
b2a2db04 by Matthew Pickering at 2023-01-05T23:02:30-05:00
Revert "configure: Drop uses of AC_PROG_CC_C99"

This reverts commit 7c6de18dd3151ead954c210336728e8686c91de6.

Centos7 using a very old version of the toolchain (autotools-2.69) where
the behaviour of these macros has not yet changed. I am reverting this
without haste as it is blocking the 9.6 branch.

Fixes #22704

- - - - -
28f8c0eb by Luite Stegeman at 2023-01-06T18:16:24+09:00
Add support for sized literals in the bytecode interpreter.

The bytecode interpreter only has branching instructions for
word-sized values. These are used for pattern matching.
Branching instructions for other types (e.g. Int16# or Word8#)
weren't needed, since unoptimized Core or STG never requires
branching on types like this.

It's now possible for optimized STG to reach the bytecode
generator (e.g. fat interface files or certain compiler flag
combinations), which requires dealing with various sized
literals in branches.

This patch improves support for generating bytecode from
optimized STG by adding the following new bytecode
instructions:

    TESTLT_I64
    TESTEQ_I64
    TESTLT_I32
    TESTEQ_I32
    TESTLT_I16
    TESTEQ_I16
    TESTLT_I8
    TESTEQ_I8
    TESTLT_W64
    TESTEQ_W64
    TESTLT_W32
    TESTEQ_W32
    TESTLT_W16
    TESTEQ_W16
    TESTLT_W8
    TESTEQ_W8

Fixes #21945

- - - - -
ac39e8e9 by Matthew Pickering at 2023-01-06T13:47:00-05:00
Only store Name in FunRhs rather than Id with knot-tied fields

All the issues here have been caused by #18758.
The goal of the ticket is to be able to talk about things like
`LTyClDecl GhcTc`. In the case of HsMatchContext,
the correct "context" is whatever we want, and in fact storing just a
`Name` is sufficient and correct context, even if the rest of the AST is
storing typechecker Ids.

So this reverts (#20415, !5579) which intended to get closed to #18758 but
didn't really and introduced a few subtle bugs.

Printing of an error message in #22695 would just hang, because we would
attempt to print the `Id` in debug mode to assertain whether it was
empty or not. Printing the Name is fine for the error message.

Another consequence is that when `-dppr-debug` was enabled the compiler would
hang because the debug printing of the Id would try and print fields
which were not populated yet.

This also led to 32070e6c2e1b4b7c32530a9566fe14543791f9a6 having to add
a workaround for the `checkArgs` function which was probably a very
similar bug to #22695.

Fixes #22695

- - - - -
c306d939 by Matthew Pickering at 2023-01-06T22:08:53-05:00
ci: Upgrade darwin, windows and freebsd CI to use GHC-9.4.3

Fixes #22599

- - - - -
0db496ff by Matthew Pickering at 2023-01-06T22:08:53-05:00
darwin ci: Explicitly pass desired build triple to configure

On the zw3rk machines for some reason the build machine was inferred to
be arm64. Setting the build triple appropiately resolve this confusion
and we produce x86 binaries.

- - - - -
2459c358 by Ben Gamari at 2023-01-06T22:09:29-05:00
rts: MUT_VAR is not a StgMutArrPtrs

There was previously a comment claiming that the MUT_VAR closure type
had the layout of StgMutArrPtrs.
- - - - -
6206cb92 by Simon Peyton Jones at 2023-01-07T12:14:40-05:00
Make FloatIn robust to shadowing

This MR fixes #22622. See the new
  Note [Shadowing and name capture]

I did a bit of refactoring in sepBindsByDropPoint too.

The bug doesn't manifest in HEAD, but it did show up in 9.4,
so we should backport this patch to 9.4

- - - - -
a960ca81 by Matthew Pickering at 2023-01-07T12:15:15-05:00
T10955: Set DYLD_LIBRARY_PATH for darwin

The correct path to direct the dynamic linker on darwin is
DYLD_LIBRARY_PATH rather than LD_LIBRARY_PATH. On recent versions of OSX
using LD_LIBRARY_PATH seems to have stopped working.

For more reading see:

https://stackoverflow.com/questions/3146274/is-it-ok-to-use-dyld-library-path-on-mac-os-x-and-whats-the-dynamic-library-s

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73484710 by Matthew Pickering at 2023-01-07T12:15:15-05:00
Skip T18623 on darwin (to add to the long list of OSs)

On recent versions of OSX, running `ulimit -v` results in

```
ulimit: setrlimit failed: invalid argument
```

Time is too short to work out what random stuff Apple has been doing
with ulimit, so just skip the test like we do for other platforms.

- - - - -
8c0ea25f by Matthew Pickering at 2023-01-07T12:15:15-05:00
Pass -Wl,-no_fixup_chains to ld64 when appropiate

Recent versions of MacOS use a version of ld where `-fixup_chains` is on by default.
This is incompatible with our usage of `-undefined dynamic_lookup`. Therefore we
explicitly disable `fixup-chains` by passing `-no_fixup_chains` to the linker on
darwin. This results in a warning of the form:

ld: warning: -undefined dynamic_lookup may not work with chained fixups

The manual explains the incompatible nature of these two flags:

     -undefined treatment
             Specifies how undefined symbols are to be treated. Options are: error, warning,
             suppress, or dynamic_lookup.  The default is error. Note: dynamic_lookup that
             depends on lazy binding will not work with chained fixups.

A relevant ticket is #22429

Here are also a few other links which are relevant to the issue:

Official comment: https://developer.apple.com/forums/thread/719961