[Git][ghc/ghc][wip/spj-wibbles] 827 commits: Be explicit about how stack usage of mvar primops are covered.

Simon Peyton Jones gitlab at gitlab.haskell.org
Thu Jul 23 11:59:51 UTC 2020



Simon Peyton Jones pushed to branch wip/spj-wibbles at Glasgow Haskell Compiler / GHC


Commits:
8c663c2c by Andreas Klebinger at 2020-03-04T16:12:14+01:00
Be explicit about how stack usage of mvar primops are covered.

This fixes #17893

[skip-ci]

- - - - -
cedd6f30 by Ben Gamari at 2020-03-05T14:53:12-05:00
rts: Add getCurrentThreadCPUTime helper

- - - - -
ace618cd by Ben Gamari at 2020-03-05T14:53:12-05:00
nonmoving-gc: Track time usage of nonmoving marking

- - - - -
022b5ad5 by Ben Gamari at 2020-03-05T14:53:12-05:00
Stats: Add sync pauses to +RTS -S output

- - - - -
06763234 by Ben Gamari at 2020-03-05T14:53:12-05:00
rts: Report nonmoving collector statistics in machine-readable output

- - - - -
70d2b995 by Ben Gamari at 2020-03-09T06:10:52-04:00
nonmoving: Fix collection of sparks

Previously sparks living in the non-moving heap would be promptly GC'd
by the minor collector since pruneSparkQueue uses the BF_EVACUATED flag,
which non-moving heap blocks do not have set.

Fix this by implementing proper support in pruneSparkQueue for
determining reachability in the non-moving heap. The story is told in
Note [Spark management in the nonmoving heap].

- - - - -
9668781a by Ben Gamari at 2020-03-09T06:11:30-04:00
gitlab-ci: Disable Sphinx documentation in Alpine build
- - - - -
8eb2c263 by Jean-Baptiste Mazon at 2020-03-09T16:33:37-04:00
Fix Windows breakage by not touching locales on Windows

- - - - -
b8dab057 by Jean-Baptiste Mazon at 2020-03-09T16:33:37-04:00
rts: ensure C numerics in heap profiles using Windows locales if needed

- - - - -
7d95260f by Jean-Baptiste Mazon at 2020-03-09T16:33:37-04:00
rts: refactor and comment profile locales

- - - - -
5b627813 by Ryan Scott at 2020-03-09T16:34:14-04:00
Use InstanceSigs in GND/DerivingVia-generated code (#17899)

Aside from making the generated code easier to read when
`-ddump-deriv` is enabled, this makes the error message in `T15073`
substantially simpler (see the updated `T15073` expected stderr).

Fixes #17899.

- - - - -
70b50778 by Ben Gamari at 2020-03-10T02:05:42-04:00
SysTools: Ensure that error parser can handle absolute paths on Windows

This fixes #17786, where the error parser fails to correctly handle the
drive name in absolute Windows paths.

Unfortunately I couldn't find a satisfactory way to test this.

- - - - -
85b861d8 by Ben Gamari at 2020-03-10T02:05:42-04:00
testsuite: Add test for #17786

This isn't pretty but it's perhaps better than nothing.

- - - - -
ee2c50cb by Sylvain Henry at 2020-03-10T02:06:33-04:00
Hadrian: track missing configure results

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ca8f51d4 by Ömer Sinan Ağacan at 2020-03-10T02:07:22-04:00
Add regression test for T17904

Closes #17904

- - - - -
5fa9cb82 by Richard Eisenberg at 2020-03-10T12:29:46-04:00
anyRewritableTyVar now looks in RuntimeReps

Previously, anyRewritableTyVar looked only at the arg and res
of `arg -> res`, but their RuntimeReps are also subject to
rewriting. Easy to fix.

Test case: typecheck/should_compile/T17024

Fixes #17024.

- - - - -
5ba01d83 by Ben Price at 2020-03-10T12:30:27-04:00
Clarify a Lint message

When developing a plugin I had a shadowing problem, where I generated
code
  app = \f{v r7B} x{v r7B} -> f{v r7B} x{v r7B}
This is obviously wrong, since the occurrence of `f` to the right of the
arrow refers to the `x` binder (they share a Unique). However, it is
rather confusing when Lint reports
  Mismatch in type between binder and occurrence
  Var: x{v rB7}
since it is printing the binder, rather than the occurrence.
It is rather easy to read this as claiming there is something wrong with
the `x` occurrence!

We change the report to explicitly print both the binder and the
occurrence variables.

- - - - -
7b2c827b by Simon Peyton Jones at 2020-03-10T12:31:15-04:00
Comments only

Clarify code added in #17852 and MR !2724

- - - - -
3300eeac by Krzysztof Gogolewski at 2020-03-10T12:31:54-04:00
Misc cleanup

- Remove Note [Existentials in shift_con_pat].
  The function shift_con_pat has been removed 15 years ago in 23f40f0e9be6d4.
- Remove kcLookupTcTyCon - it's the same as tcLookupTcTyCon
- Remove ASSERT in tyConAppArgN. It's already done by getNth,
  and it's the only reason getNth exists.
- Remove unused function nextRole

- - - - -
abf5736b by Krzysztof Gogolewski at 2020-03-10T18:05:01+01:00
Typos in comments [skip ci]

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bb586f89 by Ben Gamari at 2020-03-11T00:14:59-04:00
rts: Prefer darwin-specific getCurrentThreadCPUTime

macOS Catalina now supports a non-POSIX-compliant version of clock_gettime
which cannot use the clock_gettime codepath.

Fixes #17906.

- - - - -
20800b9a by Sylvain Henry at 2020-03-11T08:17:19-04:00
Split GHC.Iface.Utils module

* GHC.Iface.Recomp: recompilation avoidance stuff
* GHC.Iface.Make: mkIface*

Moved `writeIfaceFile` into GHC.Iface.Load alongside `readIface` and
renamed it `writeIface` for consistency.

- - - - -
1daa2029 by Greg Steuck at 2020-03-11T08:17:56-04:00
Fixed a minor typo in codegen.rst
- - - - -
0bc23338 by Ryan Scott at 2020-03-11T08:18:32-04:00
Re-quantify when generalising over rewrite rule types

Previously, `tcRules` would check for naughty quantification
candidates (see `Note [Naughty quantification candidates]` in
`TcMType`) when generalising over the type of a rewrite rule. This
caused sensible-looking rewrite rules (like those in #17710) to be
rejected. A more permissing (and easier-to-implement) approach is to
do what is described in `Note [Generalising in tcTyFamInstEqnGuts]`
in `TcTyClsDecls`: just re-quantify all the type variable binders,
regardless of the order in which the user specified them. After all,
the notion of type variable specificity has no real meaning in
rewrite rules, since one cannot "visibly apply" a rewrite rule.
I have written up this wisdom in
`Note [Re-quantify type variables in rules]` in `TcRules`.

As a result of this patch, compiling the `ExplicitForAllRules1` test
case now generates one fewer warning than it used to. As far as I can
tell, this is benign, since the thing that the disappearing warning
talked about was also mentioned in an entirely separate warning.

Fixes #17710.

- - - - -
336eac7e by Ben Gamari at 2020-03-11T08:19:08-04:00
testsuite: Mark ghci056 and ghcilink004 as fragile in unreg

As noted in #17018.

Also fix fragile declaration of T13786, which only runs in the normal
way.

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c61b9b02 by Simon Peyton Jones at 2020-03-11T08:19:44-04:00
Deepen call stack for isIn

I see quite a few warnings like:

  WARNING: file compiler/utils/Util.hs, line 593
    Over-long elem in unionLists

But the call stack is uninformative.   Better to add HasDebugCallStack
to isIn.  Ditto isn'tIn.

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3aa9b35f by Ömer Sinan Ağacan at 2020-03-11T08:20:27-04:00
Zero any slop after compaction in compacting GC

In copying GC, with the relevant debug flags enabled, we release the old
blocks after a GC, and the block allocator zeroes the space before
releasing a block. This effectively zeros the old heap.

In compacting GC we reuse the blocks and previously we didn't zero the
unused space in a compacting generation after compaction. With this
patch we zero the slop between the free pointer and the end of the block
when we're done with compaction and when switching to a new block
(because the current block doesn't have enough space for the next object
we're shifting).

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8e6febce by Sylvain Henry at 2020-03-11T20:33:37-04:00
Refactor GHC.Driver.Session (Ways and Flags)

* extract flags and ways into their own modules (with some renaming)

* remove one SOURCE import of GHC.Driver.Session from GHC.Driver.Phases

* when GHC uses dynamic linking (WayDyn), `interpWays` was only
  reporting WayDyn even if the host was profiled (WayProf).  Now it
  returns both as expected (might fix #16803).

* `mkBuildTag :: [Way] -> String` wasn't reporting a canonical tag for
  differently ordered lists. Now we sort and nub the list to fix this.

- - - - -
bc41e471 by Sylvain Henry at 2020-03-11T20:33:37-04:00
Refactor interpreterDynamic and interpreterProfiled

* `interpreterDynamic` and `interpreterProfiled` now take `Interp`
  parameters instead of DynFlags

* slight refactoring of `ExternalInterp` so that we can read the iserv
  configuration (which is pure) without reading an MVar.

- - - - -
a6989971 by Sylvain Henry at 2020-03-11T20:33:37-04:00
Use a Set to represent Ways

Should make `member` queries faster and avoid messing up with missing
`nubSort`.

Metric Increase:
    hie002

- - - - -
cb93a1a4 by Ryan Scott at 2020-03-11T20:34:14-04:00
Make DeriveFunctor-generated code require fewer beta reductions

Issue #17880 demonstrates that `DeriveFunctor`-generated code is
surprisingly fragile when rank-_n_ types are involved. The culprit is
that `$fmap` (the algorithm used to generate `fmap` implementations)
was too keen on applying arguments with rank-_n_ types to lambdas,
which fail to typecheck more often than not.

In this patch, I change `$fmap` (both the specification and the
implementation) to produce code that avoids creating as many lambdas,
avoiding problems when rank-_n_ field types arise.
See the comments titled "Functor instances" in `TcGenFunctor` for a
more detailed description. Not only does this fix #17880, but it also
ensures that the code that `DeriveFunctor` generates will continue
to work after simplified subsumption is implemented (see #17775).

What is truly amazing is that #17880 is actually a regression
(introduced in GHC 7.6.3) caused by commit
49ca2a37bef18aa57235ff1dbbf1cc0434979b1e, the fix #7436. Prior to
that commit, the version of `$fmap` that was used was almost
identical to the one used in this patch! Why did that commit change
`$fmap` then? It was to avoid severe performance issues that would
arise for recursive `fmap` implementations, such as in the example
below:

```hs
data List a = Nil | Cons a (List a) deriving Functor

-- ===>

instance Functor List where
  fmap f Nil = Nil
  fmap f (Cons x xs) = Cons (f x) (fmap (\y -> f y) xs)
```

The fact that `\y -> f y` was eta expanded caused significant
performance overheads. Commit
49ca2a37bef18aa57235ff1dbbf1cc0434979b1e fixed this performance
issue, but it went too far. As a result, this patch partially
reverts 49ca2a37bef18aa57235ff1dbbf1cc0434979b1e.

To ensure that the performance issues pre-#7436 do not resurface,
I have taken some precautionary measures:

* I have added a special case to `$fmap` for situations where the
  last type variable in an application of some type occurs directly.
  If this special case fires, we avoid creating a lambda expression.
  This ensures that we generate
  `fmap f (Cons x xs) = Cons (f x) (fmap f xs)` in the derived
  `Functor List` instance above. For more details, see
  `Note [Avoid unnecessary eta expansion in derived fmap implementations]`
  in `TcGenFunctor`.
* I have added a `T7436b` test case to ensure that the performance
  of this derived `Functor List`-style code does not regress.

When implementing this, I discovered that `$replace`, the algorithm
which generates implementations of `(<$)`, has a special case that is
very similar to the `$fmap` special case described above. `$replace`
marked this special case with a custom `Replacer` data type, which
was a bit overkill. In order to use the same machinery for both
`Functor` methods, I ripped out `Replacer` and instead implemented
a simple way to detect the special case. See the updated commentary
in `Note [Deriving <$]` for more details.

- - - - -
1f9db3e7 by Kirill Elagin at 2020-03-12T09:45:51-04:00
pretty-printer: Properly parenthesise LastStmt

After ApplicatveDo strips the last `return` during renaming, the pretty
printer has to restore it. However, if the return was followed by `$`,
the dollar was stripped too and not restored.

For example, the last stamement in:

```
  foo = do
    x <- ...
    ...
    return $ f x
```

would be printed as:

```
    return f x
```

This commit preserved the dolar, so it becomes:

```
    return $ f x
```

- - - - -
5cb93af7 by Kirill Elagin at 2020-03-12T09:45:51-04:00
pretty-printer: Do not print ApplicativeDo join

* Do not print `join` in ApplictiveStmt, unless ppr-debug
* Print parens around multiple parallel binds

When ApplicativeDo is enabled, the renamer analyses the statements of a
`do` block and in certain cases marks them as needing to be rewritten
using `join`.

For example, if you have:

```
foo = do
  a <- e1
  b <- e2
  doSomething a b
```

it will be desugared into:

```
foo = join (doSomething <$> e1 <*> e2)
```

After renaming but before desugaring the expression is stored
essentially as:

```
foo = do
  [will need join] (a <- e1 | b <- e2)
  [no return] doSomething a b
```

Before this change, the pretty printer would print a call to `join`,
even though it is not needed at this stage at all. The expression will be
actually rewritten into one using join only at desugaring, at which
point a literal call to join will be inserted.

- - - - -
3a259092 by Simon Peyton Jones at 2020-03-12T09:46:29-04:00
Expose compulsory unfoldings always

The unsafeCoerce# patch requires that unsafeCoerce# has
a compulsory unfolding that is always available.  So we have
to be careful to expose compulsory unfoldings unconditionally
and consistently.

We didn't get this quite right: #17871.  This patch fixes
it.  No real surprises here.

See Note [Always expose compulsory unfoldings] in GHC.Iface.Tidy

- - - - -
6a65b8c2 by Alp Mestanogullari at 2020-03-13T02:29:20-04:00
hadrian: improve dependency tracking for the check-* programs

The code in Rules.Register responsible for finding all the build artifacts
that Cabal installs when registering a library (static/shared libs, .hi files,
...) was looking in the wrong place. This patch fixes that logic and makes sure
we gather all those artifacts in a list to declare that the rule for a given
`.conf` file, our proxy for "Hadrian, please install this package in the package
db for this stage", also produces those artifacts under the said package
database.

We also were completely missing some logic to declare that the check-* programs
have dependencies besides their source code, at least when testing an in-tree
compiler.

Finally, this patch also removes redundant packages from 'testsuitePackages',
since they should already be covered by the stage<N>Packages lists from
Settings.Default.

With this patch, after a complete build and freezing stage 1, a change to
`compiler/parser/Parser.y` results in rebuilding the ghc lib, reinstalling it,
and rebuilding the few programs that depend on it, _including_ `check-ppr` and
`check-api-annotations` (therefore fixing #17273).

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44fad4a9 by Sylvain Henry at 2020-03-13T02:30:22-04:00
Rename isDllName

I wanted to fix the dangling comment in `isDllName` ("This is the cause
of #", #8696 is already mentioned earlier). I took the opportunity to
change the function name to better reflect what it does.

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2f292db8 by Paavo at 2020-03-13T02:31:03-04:00
Update documentation for closureSize

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f124ff0d by Ben Gamari at 2020-03-13T02:31:40-04:00
gitlab-ci: Rework triggering of release builds

Use a push option instead of tagging.

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7f25557a by Ben Gamari at 2020-03-13T10:38:09-04:00
gitlab-ci: Distinguish integer-simple test envs

Previously two integer-simple jobs declared the same test environment. One (the nightly job) was built in the perf way, the other in the validate way. Consequently they had appreciably different performance characteristics, causing in the nightly job to spuriously fail with performance changes.
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c12a2ec5 by Simon Peyton Jones at 2020-03-14T05:25:30-04:00
Fix Lint

Ticket #17590 pointed out a bug in the way the linter dealt with
type lets, exposed by the new uniqAway story.

The fix is described in Note [Linting type lets]. I ended up
putting the in-scope Ids in a different env field, le_ids,
rather than (as before) sneaking them into the TCvSubst.

Surprisingly tiresome, but done.

Metric Decrease:
    hie002

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b989845e by Sylvain Henry at 2020-03-14T05:26:11-04:00
Hadrian: fix absolute buildroot support (#17822)

Shake's "**" wildcard doesn't match absolute root. We must use "//" instead.

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4f117135 by Sylvain Henry at 2020-03-14T05:26:49-04:00
Make: refactor GMP rules

Document and use simpler rules for the ghc-gmp.h header.

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7432b327 by Sylvain Henry at 2020-03-14T05:27:28-04:00
Use correct option name (-opti) (fix #17314)

s/pgmo/opti

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8f7dd571 by Judah Jacobson at 2020-03-14T05:28:07-04:00
Allow overriding LD_STAGE0 and AR_STAGE0 in the configure script.

Previously it was possible to override the stage0 C compiler via `CC_STAGE0`,
but you couldn't override `ld` or `ar` in stage0.  This change allows overriding them
by setting `LD_STAGE0` or `AR_STAGE0`, respectively.

Our team uses this feature internally to take more control of our GHC build
and make it run more hermetically.

- - - - -
7c3e39a9 by Judah Jacobson at 2020-03-14T05:28:07-04:00
Use AC_ARG_VAR for LD_STAGE0 and AR_STAGE0.

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20d4d676 by Ben Gamari at 2020-03-14T05:28:43-04:00
nonmoving: Don't traverse filled segment list in pause

The non-moving collector would previously walk the entire filled segment
list during the preparatory pause. However, this is far more work than
is strictly necessary. We can rather get away with merely collecting the
allocators' filled segment list heads and process the lists themselves
during the concurrent phase. This can significantly reduce the maximum
gen1 GC pause time in programs with high rates of long-lived allocations.

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fdfa2d01 by Ben Gamari at 2020-03-14T05:29:18-04:00
nonmoving: Remove redundant bitmap clearing

nonmovingSweep already clears the bitmap in the sweep loop. There is no
reason to do so a second time.

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2f8c7767 by Simon Peyton Jones at 2020-03-14T05:29:55-04:00
Simple refactor of cheapEqExpr

No change in functionality.  Just seems tidier (and signficantly more
efficient) to deal with ticks directly than to call stripTicksTopE.

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88f7a762 by Simon Peyton Jones at 2020-03-14T05:29:55-04:00
Improve CSE.combineAlts

This patch improves the way that CSE combines identical
alternatives.  See #17901.

I'm still not happy about the duplication between CSE.combineAlts
and GHC.Core.Utils.combineIdenticalAlts; see the Notes with those
functions.  But this patch is a step forward.

Metric Decrease:
    T12425
    T5642

- - - - -
8b95ddd3 by Ben Gamari at 2020-03-14T05:30:31-04:00
gitlab-ci: Add integer-simple release build for Windows

Closes #16144.

- - - - -
e3c374cc by Simon Peyton Jones at 2020-03-14T05:31:07-04:00
Wrap an implication around class-sig kind errors

Ticket #17841 showed that we can get a kind error
in a class signature, but lack an enclosing implication
that binds its skolems.

This patch

* Adds the wrapping implication: the new call to
  checkTvConstraints in tcClassDecl1

* Simplifies the API to checkTvConstraints, which
  was not otherwise called at all.

* Simplifies TcErrors.report_unsolved by *not*
  initialising the TidyEnv from the typechecker lexical
  envt.  It's enough to do so from the free vars of the
  unsolved constraints; and we get silly renamings if
  we add variables twice: once from the lexical scope
  and once from the implication constraint.

- - - - -
73133a3b by Simon Peyton Jones at 2020-03-14T05:31:07-04:00
Refactoring in TcSMonad

This patch is just refactoring: no change in
behaviour.

I removed the rather complicated
    checkConstraintsTcS
    checkTvConstraintsTcS

in favour of simpler functions
    emitImplicationTcS
    emitTvImplicationTcS
    pushLevelNoWorkList

The last of these is a little strange, but overall
it's much better I think.

- - - - -
93c88c26 by Ben Gamari at 2020-03-14T05:31:42-04:00
base: Make `open` calls interruptible

As noted in #17912, `open` system calls were `safe` rather than
`interruptible`. Consequently, the program could not be interrupted with
SIGINT if stuck in a slow open operation. Fix this by marking
`c_safe_open` as interruptible.

- - - - -
bee4cdad by Vladislav Zavialov at 2020-03-14T05:32:18-04:00
Remove second tcLookupTcTyCon in tcDataDefn

Before this patch, tcDataDefn used to call tcLookupTcTyCon twice in a row:
	1. in bindTyClTyVars itself
	2. in the continuation passed to it

Now bindTyClTyVars passes the TcTyCon to the continuation, making
the second lookup unnecessary.

- - - - -
3f116d35 by Cale Gibbard at 2020-03-14T19:34:42-04:00
Enable stage1 build of haddock

The submodule has already been bumped to contain the fix.

- - - - -
49e9d739 by Ömer Sinan Ağacan at 2020-03-14T19:35:24-04:00
rts: Fix printClosure when printing fwd ptrs

- - - - -
1de3ab4a by Krzysztof Gogolewski at 2020-03-14T19:36:04-04:00
Remove unused field var_inline (#17915)

- - - - -
d30aeb4b by Krzysztof Gogolewski at 2020-03-15T03:57:41-04:00
Document restriction on SCC pragma syntax

Currently, the names of cost centres must be quoted or
be lowercase identifiers.

Fixes #17916.

- - - - -
b4774598 by Brian Foley at 2020-03-15T03:58:18-04:00
Remove some dead code

>From the notes.ghc.drop list found using weeder in #17713

- - - - -
dd6ffe6b by Viktor Dukhovni at 2020-03-15T03:58:55-04:00
Note platform-specific Foreign.C.Types in context

Also fix the markup in the general note at the top of the module.  Haddock
(usability trade-off), does not support multi-line emphasised text.

- - - - -
2e82465f by Sylvain Henry at 2020-03-15T10:57:10-04:00
Refactor CmmToAsm (disentangle DynFlags)

This patch disentangles a bit more DynFlags from the native code
generator (CmmToAsm).

In more details:

- add a new NCGConfig datatype in GHC.CmmToAsm.Config which contains the
  configuration of a native code generation session
- explicitly pass NCGConfig/Platform arguments when necessary
- as a consequence `sdocWithPlatform` is gone and there are only a few
  `sdocWithDynFlags` left
- remove the use of `unsafeGlobalDynFlags` from GHC.CmmToAsm.CFG
- remove `sdocDebugLevel` (now we pass the debug level via NCGConfig)

There are still some places where DynFlags is used, especially because
of pretty-printing (CLabel), because of Cmm helpers (such as
`cmmExprType`) and because of `Outputable` instance for the
instructions. These are left for future refactoring as this patch is
already big.

- - - - -
c35c545d by Judah Jacobson at 2020-03-15T10:57:48-04:00
Add a -no-haddock flag.

This flag undoes the effect of a previous "-haddock" flag.  Having both flags makes it easier
for build systems to enable Haddock parsing in a set of global flags, but then disable it locally for
specific targets (e.g., third-party packages whose comments don't pass the validation in the latest GHC).

I added the flag to expected-undocumented-flags.txt since `-haddock` was alreadyin that list.

- - - - -
cfcc3c9a by Ömer Sinan Ağacan at 2020-03-15T10:58:27-04:00
Fix global_link of TSOs for threads reachable via dead weaks

Fixes #17785

Here's how the problem occurs:

- In generation 0 we have a TSO that is finished (i.e. it has no more
  work to do or it is killed).

- The TSO only becomes reachable after collectDeadWeakPtrs().

- After collectDeadWeakPtrs() we switch to WeakDone phase where we don't
  move TSOs to different lists anymore (like the next gen's thread list
  or the resurrected_threads list).

- So the TSO will never be moved to a generation's thread list, but it
  will be promoted to generation 1.

- Generation 1 collected via mark-compact, and because the TSO is
  reachable it is marked, and its `global_link` field, which is bogus at
  this point (because the TSO is not in a list), will be threaded.

- Chaos ensues.

In other words, when these conditions hold:

- A TSO is reachable only after collectDeadWeakPtrs()
- It's finished (what_next is ThreadComplete or ThreadKilled)
- It's retained by mark-compact collector (moving collector doesn't
  evacuate the global_list field)

We end up doing random mutations on the heap because the TSO's
global_list field is not valid, but it still looks like a heap pointer
so we thread it during compacting GC.

The fix is simple: when we traverse old_threads lists to resurrect
unreachable threads the threads that won't be resurrected currently
stays on the old_threads lists. Those threads will never be visited
again by MarkWeak so we now reset the global_list fields. This way
compacting GC does not thread pointers to nowhere.

Testing
-------

The reproducer in #17785 is quite large and hard to build, because of
the dependencies, so I'm not adding a regression test.

In my testing the reproducer would take a less than 5 seconds to run,
and once in every ~5 runs would fail with a segfault or an assertion
error. In other cases it also fails with a test failure. Because the
tests never fail with the bug fix, assuming the code is correct, this
also means that this bug can sometimes lead to incorrect runtime
results.

After the fix I was able to run the reproducer repeatedly for about an
hour, with no runtime crashes or test failures.

To run the reproducer clone the git repo:

    $ git clone https://github.com/osa1/streamly --branch ghc-segfault

Then clone primitive and atomic-primops from their git repos and point
to the clones in cabal.project.local. The project should then be
buildable using GHC HEAD. Run the executable `properties` with `+RTS -c
-DZ`.

In addition to the reproducer above I run the test suite using:

    $ make slowtest EXTRA_HC_OPTS="-debug -with-rtsopts=-DS \
        -with-rtsopts=-c +RTS -c -RTS" SKIPWAY='nonmoving nonmoving_thr'

This enables compacting GC always in both GHC when building the test
programs and when running the test programs, and also enables sanity
checking when running the test programs. These set of flags are not
compatible for all tests so there are some failures, but I got the same
set of failures with this patch compared to GHC HEAD.

- - - - -
818b3c38 by Lysxia at 2020-03-16T23:52:42-04:00
base: add strict IO functions: readFile', getContents', hGetContents'

- - - - -
18a346a4 by Sylvain Henry at 2020-03-16T23:53:24-04:00
Modules: Core (#13009)

Update submodule: haddock

- - - - -
92327e3a by Ömer Sinan Ağacan at 2020-03-16T23:54:04-04:00
Update sanity checking for TSOs:

- Remove an invalid assumption about GC checking what_next field. The GC
  doesn't care about what_next at all, if a TSO is reachable then all
  its pointers are followed (other than global_tso, which is only
  followed by compacting GC).

- Remove checkSTACK in checkTSO: TSO stacks will be visited in
  checkHeapChain, or checkLargeObjects etc.

- Add an assertion in checkTSO to check that the global_link field is
  sane.

- Did some refactor to remove forward decls in checkGlobalTSOList and
  added braces around single-statement if statements.

- - - - -
e1aa4052 by PHO at 2020-03-17T07:36:09-04:00
Don't use non-portable operator "==" in configure.ac

The test operator "==" is a Bash extension and produces a wrong result
if /bin/sh is not Bash.

- - - - -
89f034dd by Maximilian Tagher at 2020-03-17T07:36:48-04:00
Document the units of -ddump-timings

Right now, in the output of -ddump-timings to a file, you can't tell what the units are:

```
CodeGen [TemplateTestImports]: alloc=22454880 time=14.597
```

I believe bytes/milliseconds are the correct units, but confirmation would be appreciated. I'm basing it off of this snippet from `withTiming'`:

```
when (verbosity dflags >= 2 && prtimings == PrintTimings)
  $ liftIO $ logInfo dflags (defaultUserStyle dflags)
      (text "!!!" <+> what <> colon <+> text "finished in"
       <+> doublePrec 2 time
       <+> text "milliseconds"
       <> comma
       <+> text "allocated"
       <+> doublePrec 3 (realToFrac alloc / 1024 / 1024)
       <+> text "megabytes")
```

which implies time is in milliseconds, and allocations in bytes (which divided by 1024 would be KB, and again would be MB)

- - - - -
beffa147 by Simon Peyton Jones at 2020-03-17T07:37:25-04:00
Implement mapTyCo like foldTyCo

This patch makes mapType use the successful idiom described
in TyCoRep
   Note [Specialising foldType]

I have not yet changed any functions to use mapType, though there
may be some suitable candidates.

This patch should be a no-op in terms of functionality but,
because it inlines the mapper itself, I'm hoping that there may
be some modest perf improvements.

Metric Decrease:
    T5631
    T5642
    T3064
    T9020
    T14683
    hie002
    haddock.Cabal
    haddock.base
    haddock.compiler

- - - - -
5800ebfe by Ömer Sinan Ağacan at 2020-03-17T07:38:08-04:00
Don't update ModDetails with CafInfos when opts are disabled

This is consistent with the interface file behavior where we omit
HsNoCafRefs annotations with -fomit-interface-pragmas (implied by -O0).

ModDetails and ModIface are just different representations of the same
thing, so they really need to be in sync. This patch does the right
thing and does not need too much explanation, but here's an example of a
problem not doing this causes in !2842:

    -- MyInteger.hs
    module MyInteger
      ( MyInteger (MyInteger)
      , ToMyInteger (toMyInteger)
      ) where

    newtype MyInteger = MyInteger Integer

    class ToMyInteger a where
      toMyInteger :: a -> MyInteger

    instance ToMyInteger Integer where
      toMyInteger = MyInteger {- . succ -}

    -- Main.hs
    module Main
      ( main
      ) where

    import MyInteger (MyInteger (MyInteger), toMyInteger)

    main :: IO ()
    main = do
      let (MyInteger i) = (id . toMyInteger) (41 :: Integer)
      print i

If I build this with -O0, without this fix, we generate a ModDetails with
accurate LFInfo for toMyInteger (MyInteger.$fToMyIntegerInteger) which says that
it's a LFReEntrant with arity 1. This means in the use site (Main) we tag the
value:

    R3 = MyInteger.$fToMyIntegerInteger_closure + 1;
    R2 = GHC.Base.id_closure;
    R1 = GHC.Base.._closure;
    Sp = Sp - 16;
    call stg_ap_ppp_fast(R4, R3, R2, R1) args: 24, res: 0, upd: 24;

Now we change the definition by uncommenting the `succ` part and it becomes a thunk:

    MyInteger.$fToMyIntegerInteger [InlPrag=INLINE (sat-args=0)]
      :: MyInteger.ToMyInteger GHC.Integer.Type.Integer
    [GblId[DFunId(nt)]] =
        {} \u [] $ctoMyInteger_rEA;

and its LFInfo is now LFThunk. This change in LFInfo makes a difference in the
use site: we can no longer tag it.

But becuase the interface fingerprint does not change (because ModIface does not
change) we don't rebuild Main and tag the thunk.

(1.2% increase in allocations when building T12545 on armv7 because we
generate more code without CafInfos)

Metric Increase:
    T12545

- - - - -
5b632dad by Paavo at 2020-03-17T07:38:48-04:00
Add example for Data.Semigroup.diff

- - - - -
4d85d68b by Paavo at 2020-03-17T07:38:48-04:00
Clean up

- - - - -
75168d07 by Paavo at 2020-03-17T07:38:48-04:00
Make example collapsible

- - - - -
53ff2cd0 by Richard Eisenberg at 2020-03-17T13:46:57+00:00
Fix #17021 by checking more return kinds

All the details are in new Note [Datatype return kinds] in
TcTyClsDecls.

Test case: typecheck/should_fail/T17021{,b}
           typecheck/should_compile/T17021a

Updates haddock submodule

- - - - -
528df8ec by Sylvain Henry at 2020-03-18T10:06:43-04:00
Modules: Core operations (#13009)

- - - - -
4e8a71c1 by Richard Eisenberg at 2020-03-18T10:07:19-04:00
Add release note about fix to #16502.

We thought we needed to update the manual, but the fix for #16502
actually brings the implementation in line with the manual. So we
just alert users of how to update their code.

- - - - -
5cbf9934 by Andreas Klebinger at 2020-03-19T00:39:27-04:00
Update "GHC differences to the FFI Chapter" in user guide.

The old entry had a heavy focus on how things had been. Which is
not what I generally look for in a user guide.

I also added a small section on behaviour of nested safe ffi calls.

[skip-ci]

- - - - -
b03fd3bc by Sebastian Graf at 2020-03-19T00:40:06-04:00
PmCheck: Use ConLikeSet to model negative info

In #17911, Simon recognised many warnings stemming from over-long list
unions while coverage checking Cabal's `LicenseId` module.

This patch introduces a new `PmAltConSet` type which uses a `UniqDSet`
instead of an association list for `ConLike`s. For `PmLit`s, it will
still use an assocation list, though, because a similar map data
structure would entail a lot of busy work.

Fixes #17911.

- - - - -
64f20756 by Sylvain Henry at 2020-03-19T12:16:49-04:00
Refactoring: use Platform instead of DynFlags when possible

Metric Decrease:
    ManyConstructors
    T12707
    T13035
    T1969

- - - - -
cb1785d9 by Ömer Sinan Ağacan at 2020-03-19T12:16:54-04:00
FastString: fix eager reading of string ptr in hashStr

This read causes NULL dereferencing when len is 0.

Fixes #17909

In the reproducer in #17909 this bug is triggered as follows:

- SimplOpt.dealWithStringLiteral is called with a single-char string
  ("=" in #17909)

- tailFS gets called on the FastString of the single-char string.

- tailFS checks the length of the string, which is 1, and calls
  mkFastStringByteString on the tail of the ByteString, which is an
  empty ByteString as the original ByteString has only one char.

- ByteString's unsafeUseAsCStringLen returns (NULL, 0) for the empty
  ByteString, which is passed to mkFastStringWith.

- mkFastStringWith gets hash of the NULL pointer via hashStr, which
  fails on empty strings because of this bug.

- - - - -
73a7383e by Richard Eisenberg at 2020-03-20T20:42:56-04:00
Simplify treatment of heterogeneous equality

Previously, if we had a [W] (a :: k1) ~ (rhs :: k2), we would
spit out a [D] k1 ~ k2 and part the W as irreducible, hoping for
a unification. But we needn't do this. Instead, we now spit out
a [W] co :: k2 ~ k1 and then use co to cast the rhs of the original
Wanted. This means that we retain the connection between the
spat-out constraint and the original.

The problem with this new approach is that we cannot use the
casted equality for substitution; it's too like wanteds-rewriting-
wanteds. So, we forbid CTyEqCans that mention coercion holes.

All the details are in Note [Equalities with incompatible kinds]
in TcCanonical.

There are a few knock-on effects, documented where they occur.

While debugging an error in this patch, Simon and I ran into
infelicities in how patterns and matches are printed; we made
small improvements.

This patch includes mitigations for #17828, which causes spurious
pattern-match warnings. When #17828 is fixed, these lines should
be removed.

- - - - -
faa36e5b by Sylvain Henry at 2020-03-20T20:43:41-04:00
Hadrian: ignore in-tree GMP objects with ``--lint``

- - - - -
9a96ff6b by Richard Eisenberg at 2020-03-20T20:44:17-04:00
Update core spec to reflect changes to Core.

Key changes:
 * Adds a new rule for forall-coercions over coercion variables, which
was implemented but conspicuously missing from the spec.
 * Adds treatment for FunCo.
 * Adds treatment for ForAllTy over coercion variables.
 * Improves commentary (including restoring a Note lost in
03d4852658e1b7407abb4da84b1b03bfa6f6db3b) in the source.

No changes to running code.

- - - - -
7e0451c6 by Sergej Jaskiewicz at 2020-03-20T20:44:55-04:00
Fix event message in withTiming'

This typo caused generating 'end' events without the corresponding 'begin' events.

- - - - -
1542a626 by Ben Gamari at 2020-03-22T22:37:47-04:00
fs.h: Add missing declarations on Windows

- - - - -
3bcf2ccd by Ben Gamari at 2020-03-22T22:37:47-04:00
Bump process submodule

Avoids redundant case alternative warning.

- - - - -
3b363ef9 by Ben Gamari at 2020-03-22T22:37:47-04:00
testsuite: Normalize slashes in ghc-api annotations output

Enable `normalise_slashes` on `annotations`, `listcomps`, and
`parseTree` to fix Windows failures.

- - - - -
25fc9429 by Ben Gamari at 2020-03-22T22:37:47-04:00
testsuite: Update expected output on Windows

- - - - -
7f58ec6d by Ben Gamari at 2020-03-22T22:37:47-04:00
testsuite: Fix TOP of T17786

- - - - -
aadcd909 by GHC GitLab CI at 2020-03-22T22:37:47-04:00
testsuite: Update expected output on Windows

- - - - -
dc1eb10d by GHC GitLab CI at 2020-03-22T22:37:47-04:00
hadrian: Fix executable extension passed to testsuite driver

- - - - -
58f62e2c by GHC GitLab CI at 2020-03-22T22:37:47-04:00
gitlab-ci: Require that Windows-hadrian job passes

- - - - -
8dd2415d by Ben Gamari at 2020-03-22T22:37:47-04:00
hadrian: Eliminate redundant .exe from GHC path

Previously we were invoking:

    bash -c
    "c:/GitLabRunner/builds/eEQrxK4p/0/ghc/ghc/toolchain/bin/ghc.exe.exe
    testsuite/mk/ghc-config.hs -o _build/test/bin/ghc-config.exe"

- - - - -
373621f6 by Ben Gamari at 2020-03-22T22:37:47-04:00
Bump hsc2hs submodule

- - - - -
abc02b40 by Hécate at 2020-03-22T22:38:33-04:00
Annotate the non-total function in Data.Foldable as such

- - - - -
19f12557 by Josef Svenningsson at 2020-03-23T14:05:33-04:00
Fix ApplicativeDo regression #17835

A previous fix for #15344 made sure that monadic 'fail' is used properly
when translating ApplicativeDo. However, it didn't properly account
for when a 'fail' will be inserted which resulted in some programs
failing with a type error.

- - - - -
2643ba46 by Paavo at 2020-03-24T08:31:32-04:00
Add example and doc for Arg (Fixes #17153)

- - - - -
703221f4 by Roland Senn at 2020-03-25T14:45:04-04:00
Use export list of Main module in function TcRnDriver.hs:check_main (Fix #16453)

- Provide the export list of the `Main` module as parameter to the
  `compiler/typecheck/TcRnDriver.hs:check_main` function.
- Instead of `lookupOccRn_maybe` call the function `lookupInfoOccRn`.
  It returns the list `mains_all` of all the main functions in scope.
- Select from this list `mains_all` all `main` functions that are in
  the export list of the `Main` module.
- If this new list contains exactly one single `main` function, then
  typechecking continues.
- Otherwise issue an appropriate error message.

- - - - -
3e27205a by Sebastian Graf at 2020-03-25T14:45:40-04:00
Remove -fkill-absence and -fkill-one-shot flags

They seem to be a benchmarking vestige of the Cardinality paper and
probably shouldn't have been merged to HEAD in the first place.

- - - - -
262e42aa by Peter Trommler at 2020-03-25T22:41:39-04:00
Do not panic on linker errors

- - - - -
0de03cd7 by Sylvain Henry at 2020-03-25T22:42:02-04:00
DynFlags refactoring III

Use Platform instead of DynFlags when possible:
* `tARGET_MIN_INT` et al. replaced with `platformMinInt` et al.
* no more DynFlags in PreRules: added a new `RuleOpts` datatype
* don't use `wORD_SIZE` in the compiler
* make `wordAlignment` use `Platform`
* make `dOUBLE_SIZE` a constant

Metric Decrease:
    T13035
    T1969

- - - - -
7a04920b by Tristan Cacqueray at 2020-03-25T22:42:06-04:00
Base: fix a typo in liftA doc

This change removes an extra '|' that should not be rendered in
the liftA documentation.

Tracking: #17929

- - - - -
1c5a15f7 by Tristan Cacqueray at 2020-03-25T22:42:06-04:00
Base: add Control.Applicative optional example

This change adds an optional example.

Tracking: #17929

- - - - -
6d172e63 by Tristan Cacqueray at 2020-03-25T22:42:06-04:00
Base: add markup around Except

- - - - -
eb2162c8 by John Ericson at 2020-03-26T12:37:08-04:00
Remove unused `ghciTablesNextToCode` from compiler proper

- - - - -
f51efc4b by Joachim Breitner at 2020-03-26T12:37:09-04:00
Prepare to use run-time tablesNextToCode in compiler exclusively

Factor out CPP as much as possible to prepare for runtime
determinattion.

Progress towards #15548

- - - - -
1c446220 by Joachim Breitner at 2020-03-26T12:37:09-04:00
Use run-time tablesNextToCode in compiler exclusively (#15548)

Summary:

 - There is no more use of the TABLES_NEXT_TO_CODE CPP macro in
   `compiler/`. GHCI_TABLES_NEXT_TO_CODE is also removed entirely.
   The field within `PlatformMisc` within `DynFlags` is used instead.

 - The field is still not exposed as a CLI flag. We might consider some
   way to ensure the right RTS / libraries are used before doing that.

Original reviewers:

Original subscribers: TerrorJack, rwbarton, carter

Original Differential Revision: https://phabricator.haskell.org/D5082

- - - - -
1941ef4f by Sylvain Henry at 2020-03-29T17:28:51-04:00
Modules: Types (#13009)

Update Haddock submodule

Metric Increase:
   haddock.compiler

- - - - -
1c7c6f1a by Sylvain Henry at 2020-03-29T17:28:51-04:00
Remove GHC.Types.Unique.Map module

This module isn't used anywhere in GHC.

- - - - -
f1a6c73d by Sylvain Henry at 2020-03-29T17:28:51-04:00
Merge GHC.Types.CostCentre.Init into GHC.Driver.CodeOutput

- - - - -
54250f2d by Simon Peyton Jones at 2020-03-29T17:29:30-04:00
Demand analysis: simplify the demand for a RHS

Ticket #17932 showed that we were using a stupid demand for the RHS
of a let-binding, when the result is a product.  This was the result
of a "fix" in 2013, which (happily) turns out to no longer be
necessary.

So I just deleted the code, which simplifies the demand analyser,
and fixes #17932. That in turn uncovered that the anticipation
of worker/wrapper in CPR analysis was inaccurate, hence the logic
that decides whether to unbox an argument in WW was extracted into
a function `wantToUnbox`, now consulted by CPR analysis.

I tried nofib, and got 0.0% perf changes.

All this came up when messing about with !2873 (ticket #17917),
but is idependent of it.

Unfortunately, this patch regresses #4267 and realised that it is now
blocked on #16335.

- - - - -
03060b2f by Ben Gamari at 2020-03-29T17:30:05-04:00
testsuite: Fix T17786 on Windows

Fixes line ending normalization issue.

- - - - -
1f7995ba by Ben Gamari at 2020-03-29T17:30:05-04:00
testsuite: Fix T17786

Fix missing quoting and expected exit code.

- - - - -
ef9c608e by Ben Gamari at 2020-03-29T17:30:05-04:00
testsuite: Mark T12971 as broken on Windows

Due to #17945.

- - - - -
e54500c1 by Sylvain Henry at 2020-03-29T17:30:47-04:00
Store ComponentId details

As far as GHC is concerned, installed package components ("units") are
identified by an opaque ComponentId string provided by Cabal. But we
don't want to display it to users (as it contains a hash) so GHC queries
the database to retrieve some infos about the original source package
(name, version, component name).

This patch caches these infos in the ComponentId itself so that we don't
need to provide DynFlags (which contains installed package informations)
to print a ComponentId.

In the future we want GHC to support several independent package states
(e.g. for plugins and for target code), hence we need to avoid
implicitly querying a single global package state.

- - - - -
7e7cb714 by Marius Bakke at 2020-03-29T17:31:27-04:00
testsuite: Remove test that dlopens a PIE object.

glibc 2.30 disallowed dlopening PIE objects, so just remove the test.
Fixes #17952.

- - - - -
6c8f80d8 by Andreas Klebinger at 2020-03-29T17:32:04-04:00
Correct haddocks for testBit in Data.Bits

It conflated the nth bit with the bit at offset n.

Now we instead give the definition in terms of `bit and `.&.`
on top of clearer phrasing.

- - - - -
c916f190 by Andreas Klebinger at 2020-03-29T17:32:04-04:00
Apply suggestion to libraries/base/Data/Bits.hs
- - - - -
64bf7f51 by Ben Gamari at 2020-03-29T17:32:41-04:00
gitlab-ci: Add FreeBSD release job

- - - - -
a0d8e92e by Ryan Scott at 2020-03-29T17:33:20-04:00
Run checkNewDataCon before constraint-solving newtype constructors

Within `checkValidDataCon`, we used to run `checkValidType` on the
argument types of a newtype constructor before running
`checkNewDataCon`, which ensures that the user does not attempt
non-sensical things such as newtypes with multiple arguments or
constraints. This works out in most situations, but this falls over
on a corner case revealed in #17955:

```hs
newtype T = Coercible () T => T ()
```

`checkValidType`, among other things, peforms an ambiguity check on
the context of a data constructor, and that it turn invokes the
constraint solver. It turns out that there is a special case in the
constraint solver for representational equalities (read: `Coercible`
constraints) that causes newtypes to be unwrapped (see
`Note [Unwrap newtypes first]` in `TcCanonical`). This special case
does not know how to cope with an ill formed newtype like `T`, so
it ends up panicking.

The solution is surprisingly simple: just invoke `checkNewDataCon`
before `checkValidType` to ensure that the illicit newtype
constructor context is detected before the constraint solver can
run amok with it.

Fixes #17955.

- - - - -
45eb9d8c by Krzysztof Gogolewski at 2020-03-29T17:33:59-04:00
Minor cleanup

- Simplify mkBuildExpr, the function newTyVars was called
  only on a one-element list.
- TTG: use noExtCon in more places. This is more future-proof.
- In zonkExpr, panic instead of printing a warning.

- - - - -
f024b6e3 by Sylvain Henry at 2020-03-30T12:48:39+02:00
Expect T4267 to pass

Since 54250f2d8de910b094070c1b48f086030df634b1 we expected T4267 to
fail, but it passes on CI.

- - - - -
57b888c0 by Ryan Scott at 2020-03-31T10:54:20-04:00
Require GHC 8.8 as the minimum compiler for bootstrapping

This allows us to remove several bits of CPP that are either always
true or no longer reachable. As an added bonus, we no longer need to
worry about importing `Control.Monad.Fail.fail` qualified to avoid
clashing with `Control.Monad.fail`, since the latter is now the same
as the former.

- - - - -
33f09551 by Ryan Scott at 2020-03-31T10:54:57-04:00
Add regression test for #17963

The panic in #17963 happened to be fixed by commit
e3c374cc5bd7eb49649b9f507f9f7740697e3f70. This patch adds a
regression test to ensure that it remains fixed.

Fixes #17963.

- - - - -
09a36e80 by Ömer Sinan Ağacan at 2020-03-31T10:55:37-04:00
Simplify stderrSupportsAnsiColors

The combinator andM is used only once, and the code is shorter and
simpler if you inline it.

- - - - -
95bccdd0 by Ben Gamari at 2020-03-31T10:56:19-04:00
base: Ensure that encoding global variables aren't inlined

As noted in #17970, these (e.g. `getFileSystemEncoding` and
`setFileSystemEncoding`) previously had unfoldings, which would
break their global-ness.

While not strictly necessary, I also add a NOINLINE on
`initLocaleEncoding` since it is used in `System.IO`, ensuring that we
only system's query the locale encoding once.

Fixes #17970.

- - - - -
982aaa83 by Andreas Klebinger at 2020-03-31T10:56:55-04:00
Update hadrian index revision.

Required in order to build hadrian using ghc-8.10

- - - - -
4b9c5864 by Ben Gamari at 2020-03-31T10:57:32-04:00
integer-gmp: Bump version and add changelog entry

- - - - -
9b39f2e6 by Ryan Scott at 2020-04-01T01:20:00-04:00
Clean up "Eta reduction for data families" Notes

Before, there were two distinct Notes named
"Eta reduction for data families". This renames one of them to
"Implementing eta reduction for data families" to disambiguate the
two and fixes references in other parts of the codebase to ensure
that they are pointing to the right place.

Fixes #17313.

[ci skip]

- - - - -
7627eab5 by Ryan Scott at 2020-04-01T01:20:38-04:00
Fix the changelog/@since information for hGetContents'/getContents'/readFile'

Fixes #17979.

[ci skip]

- - - - -
0002db1b by Sylvain Henry at 2020-04-01T01:21:27-04:00
Kill wORDS_BIGENDIAN and replace it with platformByteOrder (#17957)

Metric Decrease:
    T13035
    T1969

- - - - -
7b217179 by Sebastian Graf at 2020-04-01T15:03:24-04:00
PmCheck: Adjust recursion depth for inhabitation test

In #17977, we ran into the reduction depth limit of the typechecker.
That was only a symptom of a much broader issue: The recursion depth
of the coverage checker for trying to instantiate strict fields in the
`nonVoid` test was far too high (100, the `defaultMaxTcBound`).

As a result, we were performing quite poorly on `T17977`.
Short of a proper termination analysis to prove emptyness of a type,
we just arbitrarily default to a much lower recursion limit of 3.

Fixes #17977.

- - - - -
3c09f636 by Andreas Klebinger at 2020-04-01T15:03:59-04:00
Make hadrian pass on the no-colour setting to GHC.

Fixes #17983.

- - - - -
b943b25d by Simon Peyton Jones at 2020-04-02T01:45:58-04:00
Re-engineer the binder-swap transformation

The binder-swap transformation is implemented by the occurrence
analyser -- see Note [Binder swap] in OccurAnal. However it had
a very nasty corner in it, for the case where the case scrutinee
was a GlobalId.  This led to trouble and hacks, and ultimately
to #16296.

This patch re-engineers how the occurrence analyser implements
the binder-swap, by actually carrying out a substitution rather
than by adding a let-binding.  It's all described in
Note [The binder-swap substitution].

I did a few other things along the way

* Fix a bug in StgCse, which could allow a loop breaker to be CSE'd
  away.  See Note [Care with loop breakers] in StgCse.  I think it can
  only show up if occurrence analyser sets up bad loop breakers, but
  still.

* Better commenting in SimplUtils.prepareAlts

* A little refactoring in CoreUnfold; nothing significant
  e.g. rename CoreUnfold.mkTopUnfolding to mkFinalUnfolding

* Renamed CoreSyn.isFragileUnfolding to hasCoreUnfolding

* Move mkRuleInfo to CoreFVs

We observed respectively 4.6% and 5.9% allocation decreases for the following
tests:

Metric Decrease:
    T9961
    haddock.base

- - - - -
42d68364 by Sebastian Graf at 2020-04-02T01:46:34-04:00
Preserve precise exceptions in strictness analysis

Fix #13380 and #17676 by

1. Changing `raiseIO#` to have `topDiv` instead of `botDiv`
2. Give it special treatment in `Simplifier.Util.mkArgInfo`, treating it
   as if it still had `botDiv`, to recover dead code elimination.

This is the first commit of the plan outlined in
https://gitlab.haskell.org/ghc/ghc/-/merge_requests/2525#note_260886.

- - - - -
0a88dd11 by Ömer Sinan Ağacan at 2020-04-02T01:47:25-04:00
Fix a pointer format string in RTS

- - - - -
5beac042 by Ömer Sinan Ağacan at 2020-04-02T01:48:05-04:00
Remove unused closure stg_IND_direct

- - - - -
88f38b03 by Ben Gamari at 2020-04-02T01:48:42-04:00
Session: Memoize stderrSupportsAnsiColors

Not only is this a reasonable efficiency measure but it avoids making
reentrant calls into ncurses, which is not thread-safe. See #17922.

- - - - -
27740f24 by Ryan Scott at 2020-04-02T01:49:21-04:00
Make Hadrian build with Cabal-3.2

GHC 8.10 ships with `Cabal-3.2.0.0`, so it would be convenient to
make Hadrian supporting building against 3.2.* instead of having to
rebuild the entirety of `Cabal-3.0.0.0`. There is one API change in
`Cabal-3.2.*` that affects Hadrian: the `synopsis` and `description`
functions now return `ShortText` instead of `String`. Since Hadrian
manipulates these `String`s in various places, I found that the
simplest fix was to use CPP to convert `ShortText` to `String`s
where appropriate.

- - - - -
49802002 by Sylvain Henry at 2020-04-02T01:50:00-04:00
Update Stack resolver for hadrian/build-stack

Broken by 57b888c0e90be7189285a6b078c30b26d0923809

- - - - -
30a63e79 by Ryan Scott at 2020-04-02T01:50:36-04:00
Fix two ASSERT buglets in reifyDataCon

Two `ASSERT`s in `reifyDataCon` were always using `arg_tys`, but
`arg_tys` is not meaningful for GADT constructors. In fact, it's
worse than non-meaningful, since using `arg_tys` when reifying a
GADT constructor can lead to failed `ASSERT`ions, as #17305
demonstrates.

This patch applies the simplest possible fix to the immediate
problem. The `ASSERT`s now use `r_arg_tys` instead of `arg_tys`, as
the former makes sure to give something meaningful for GADT
constructors. This makes the panic go away at the very least. There
is still an underlying issue with the way the internals of
`reifyDataCon` work, as described in
https://gitlab.haskell.org/ghc/ghc/issues/17305#note_227023, but we
leave that as future work, since fixing the underlying issue is
much trickier (see
https://gitlab.haskell.org/ghc/ghc/issues/17305#note_227087).

- - - - -
ef7576c4 by Zubin Duggal at 2020-04-03T06:24:56-04:00
Add outputable instances for the types in GHC.Iface.Ext.Types, add -ddump-hie
flag to dump pretty printed contents of the .hie file

Metric Increase:
   hie002

Because of the regression on i386:

compile_time/bytes allocated increased from i386-linux-deb9 baseline @ HEAD~10:
    Expected    hie002 (normal) compile_time/bytes allocated: 583014888.0 +/-10%
    Lower bound hie002 (normal) compile_time/bytes allocated:   524713399
    Upper bound hie002 (normal) compile_time/bytes allocated:   641316377
    Actual      hie002 (normal) compile_time/bytes allocated:   877986292
    Deviation   hie002 (normal) compile_time/bytes allocated:        50.6 %
*** unexpected stat test failure for hie002(normal)

- - - - -
9462452a by Andreas Klebinger at 2020-04-03T06:25:33-04:00
Improve and refactor StgToCmm codegen for DataCons.

We now differentiate three cases of constructor bindings:

1)Bindings which we can "replace" with a reference to
  an existing closure. Reference the replacement closure
  when accessing the binding.
2)Bindings which we can "replace" as above. But we still
  generate a closure which will be referenced by modules
  importing this binding.
3)For any other binding generate a closure. Then reference
  it.

Before this patch 1) did only apply to local bindings and we
didn't do 2) at all.

- - - - -
a214d214 by Moritz Bruder at 2020-04-03T06:26:11-04:00
Add singleton to NonEmpty in libraries/base

This adds a definition to construct a singleton non-empty list
(Data.List.NonEmpty) according to issue #17851.

- - - - -
f7597aa0 by Sylvain Henry at 2020-04-03T06:26:54-04:00
Testsuite: measure compiler stats for T16190

We were mistakenly measuring program stats

- - - - -
a485c3c4 by Sylvain Henry at 2020-04-03T06:26:54-04:00
Move blob handling into StgToCmm

Move handling of big literal strings from CmmToAsm to StgToCmm. It
avoids the use of `sdocWithDynFlags` (cf #10143). We might need to move
this handling even higher in the pipeline in the future (cf #17960):
this patch will make it easier.

- - - - -
cc2918a0 by Sylvain Henry at 2020-04-03T06:26:54-04:00
Refactor CmmStatics

In !2959 we noticed that there was some redundant code (in GHC.Cmm.Utils
and GHC.Cmm.StgToCmm.Utils) used to deal with `CmmStatics` datatype
(before SRT generation) and `RawCmmStatics` datatype (after SRT
generation).

This patch removes this redundant code by using a single GADT for
(Raw)CmmStatics.

- - - - -
9e60273d by Maxim Koltsov at 2020-04-03T06:27:32-04:00
Fix haddock formatting in Control.Monad.ST.Lazy.Imp.hs

- - - - -
1b7e8a94 by Andreas Klebinger at 2020-04-03T06:28:08-04:00
Turn newlines into spaces for hadrian/ghci.

The newlines break the command on windows.

- - - - -
4291bdda by Simon Peyton Jones at 2020-04-03T06:28:44-04:00
Major improvements to the specialiser

This patch is joint work of Alexis King and Simon PJ.  It does some
significant refactoring of the type-class specialiser.  Main highlights:

* We can specialise functions with types like
     f :: Eq a => a -> Ord b => b => blah
  where the classes aren't all at the front (#16473).  Here we can
  correctly specialise 'f' based on a call like
     f @Int @Bool dEqInt x dOrdBool
  This change really happened in an earlier patch
     commit 2d0cf6252957b8980d89481ecd0b79891da4b14b
     Author: Sandy Maguire <sandy at sandymaguire.me>
     Date:   Thu May 16 12:12:10 2019 -0400
  work that this new patch builds directly on that work, and refactors
  it a bit.

* We can specialise functions with implicit parameters (#17930)
     g :: (?foo :: Bool, Show a) => a -> String
  Previously we could not, but now they behave just like a non-class
  argument as in 'f' above.

* We can specialise under-saturated calls, where some (but not all of
  the dictionary arguments are provided (#17966).  For example, we can
  specialise the above 'f' based on a call
     map (f @Int dEqInt) xs
  even though we don't (and can't) give Ord dictionary.

  This may sound exotic, but #17966 is a program from the wild, and
  showed significant perf loss for functions like f, if you need
  saturation of all dictionaries.

* We fix a buglet in which a floated dictionary had a bogus demand
  (#17810), by using zapIdDemandInfo in the NonRec case of specBind.

* A tiny side benefit: we can drop dead arguments to specialised
  functions; see Note [Drop dead args from specialisations]

* Fixed a bug in deciding what dictionaries are "interesting"; see
  Note [Keep the old dictionaries interesting]

This is all achieved by by building on Sandy Macguire's work in
defining SpecArg, which mkCallUDs uses to describe the arguments of
the call. Main changes:

* Main work is in specHeader, which marched down the [InBndr] from the
  function definition and the [SpecArg] from the call site, together.

* specCalls no longer has an arity check; the entire mechanism now
  handles unders-saturated calls fine.

* mkCallUDs decides on an argument-by-argument basis whether to
  specialise a particular dictionary argument; this is new.
  See mk_spec_arg in mkCallUDs.

It looks as if there are many more lines of code, but I think that
all the extra lines are comments!

- - - - -
40a85563 by Ömer Sinan Ağacan at 2020-04-03T18:26:19+03:00
Revert accidental change in 9462452

[ci skip]

- - - - -
bd75e5da by Ryan Scott at 2020-04-04T07:07:58-04:00
Enable ImpredicativeTypes internally when typechecking selector bindings

This is necessary for certain record selectors with higher-rank
types, such as the examples in #18005. See
`Note [Impredicative record selectors]` in `TcTyDecls`.

Fixes #18005.

- - - - -
dcfe29c8 by Ömer Sinan Ağacan at 2020-04-06T13:16:08-04:00
Don't override proc CafInfos in ticky builds

Fixes #17947

When we have a ticky label for a proc, IdLabels for the ticky counter
and proc entry share the same Name. This caused overriding proc CafInfos
with the ticky CafInfos (i.e. NoCafRefs) during SRT analysis.

We now ignore the ticky labels when building SRTMaps. This makes sense
because:

- When building the current module they don't need to be in SRTMaps as
  they're initialized as non-CAFFY (see mkRednCountsLabel), so they
  don't take part in the dependency analysis and they're never added to
  SRTs.

  (Reminder: a "dependency" in the SRT analysis is a CAFFY dependency,
  non-CAFFY uses are not considered as dependencies for the algorithm)

- They don't appear in the interfaces as they're not exported, so it
  doesn't matter for cross-module concerns whether they're in the SRTMap
  or not.

See also the new Note [Ticky labels in SRT analysis].

- - - - -
cec2c71f by Simon Peyton Jones at 2020-04-06T13:16:44-04:00
Fix an tricky specialiser loop

Issue #17151 was a very tricky example of a bug in which the
specialiser accidentally constructs a recurive dictionary,
so that everything turns into bottom.

I have fixed variants of this bug at least twice before:
see Note [Avoiding loops].  It was a bit of a struggle
to isolate the problem, greatly aided by the work that
Alexey Kuleshevich did in distilling a test case.

Once I'd understood the problem, it was not difficult to fix,
though it did lead me a bit of refactoring in specImports.

- - - - -
e850d14f by Simon Peyton Jones at 2020-04-06T13:16:44-04:00
Refactoring only

This refactors DictBinds into a data type rather than a pair.
No change in behaviour, just better code

- - - - -
f38e8d61 by Daniel Gröber at 2020-04-07T02:00:05-04:00
rts: ProfHeap: Fix memory leak when not compiled with profiling

If we're doing heap profiling on an unprofiled executable we keep
allocating new space in initEra via nextEra on each profiler run but we
don't have a corresponding freeEra call.

We do free the last era in endHeapProfiling but previous eras will have
been overwritten by initEra and will never get free()ed.

Metric Decrease:
    space_leak_001

- - - - -
bcd66859 by Sebastian Graf at 2020-04-07T02:00:41-04:00
Re-export GHC.Magic.noinline from base

- - - - -
3d2991f8 by Ben Gamari at 2020-04-07T18:36:09-04:00
simplifier: Kill off ufKeenessFactor

We used to have another factor, ufKeenessFactor, which would scale the
discounts before they were subtracted from the size. This was justified
with the following comment:

  -- We multiple the raw discounts (args_discount and result_discount)
  -- ty opt_UnfoldingKeenessFactor because the former have to do with
  --  *size* whereas the discounts imply that there's some extra
  --  *efficiency* to be gained (e.g. beta reductions, case reductions)
  -- by inlining.

However, this is highly suspect since it means that we subtract a
*scaled* size from an absolute size, resulting in crazy (e.g. negative)
scores in some cases (#15304). We consequently killed off
ufKeenessFactor and bumped up the ufUseThreshold to compensate.

Adjustment of unfolding use threshold
=====================================

Since this removes a discount from our inlining heuristic, I revisited our
default choice of -funfolding-use-threshold to minimize the change in
overall inlining behavior. Specifically, I measured runtime allocations
and executable size of nofib and the testsuite performance tests built
using compilers (and core libraries) built with several values of
-funfolding-use-threshold.

This comes as a result of a quantitative comparison of testsuite
performance and code size as a function of ufUseThreshold, comparing
GHC trees using values of 50, 60, 70, 80, 90, and 100. The test set
consisted of nofib and the testsuite performance tests.
A full summary of these measurements are found in the description of
!2608

Comparing executable sizes (relative to the base commit) across all
nofib tests, we see that sizes are similar to the baseline:

            gmean      min      max   median
thresh
50         -6.36%   -7.04%   -4.82%   -6.46%
60         -5.04%   -5.97%   -3.83%   -5.11%
70         -2.90%   -3.84%   -2.31%   -2.92%
80         -0.75%   -2.16%   -0.42%   -0.73%
90         +0.24%   -0.41%   +0.55%   +0.26%
100        +1.36%   +0.80%   +1.64%   +1.37%
baseline   +0.00%   +0.00%   +0.00%   +0.00%

Likewise, looking at runtime allocations we see that 80 gives slightly
better optimisation than the baseline:

            gmean      min      max   median
thresh
50         +0.16%   -0.16%   +4.43%   +0.00%
60         +0.09%   -0.00%   +3.10%   +0.00%
70         +0.04%   -0.09%   +2.29%   +0.00%
80         +0.02%   -1.17%   +2.29%   +0.00%
90         -0.02%   -2.59%   +1.86%   +0.00%
100        +0.00%   -2.59%   +7.51%   -0.00%
baseline   +0.00%   +0.00%   +0.00%   +0.00%

Finally, I had to add a NOINLINE in T4306 to ensure that `upd` is
worker-wrappered as the test expects. This makes me wonder whether the
inlining heuristic is now too liberal as `upd` is quite a large
function. The same measure was taken in T12600.

             Wall clock time compiling Cabal with -O0
thresh       50     60     70     80     90      100    baseline
build-Cabal  93.88  89.58  92.59  90.09  100.26  94.81  89.13

Also, this change happens to avoid the spurious test output in
`plugin-recomp-change` and `plugin-recomp-change-prof` (see #17308).

Metric Decrease:
    hie002
    T12234
    T13035
    T13719
    T14683
    T4801
    T5631
    T5642
    T9020
    T9872d
    T9961
Metric Increase:
    T12150
    T12425
    T13701
    T14697
    T15426
    T1969
    T3064
    T5837
    T6048
    T9203
    T9872a
    T9872b
    T9872c
    T9872d
    haddock.Cabal
    haddock.base
    haddock.compiler

- - - - -
255418da by Sylvain Henry at 2020-04-07T18:36:49-04:00
Modules: type-checker (#13009)

Update Haddock submodule

- - - - -
04b6cf94 by Ryan Scott at 2020-04-07T19:43:20-04:00
Make NoExtCon fields strict

This changes every unused TTG extension constructor to be strict in
its field so that the pattern-match coverage checker is smart enough
any such constructors are unreachable in pattern matches. This lets
us remove nearly every use of `noExtCon` in the GHC API. The only
ones we cannot remove are ones underneath uses of `ghcPass`, but that
is only because GHC 8.8's and 8.10's coverage checkers weren't smart
enough to perform this kind of reasoning. GHC HEAD's coverage
checker, on the other hand, _is_ smart enough, so we guard these uses
of `noExtCon` with CPP for now.

Bumps the `haddock` submodule.

Fixes #17992.

- - - - -
7802fa17 by Ryan Scott at 2020-04-08T16:43:44-04:00
Handle promoted data constructors in typeToLHsType correctly

Instead of using `nlHsTyVar`, which hardcodes `NotPromoted`, have
`typeToLHsType` pick between `Promoted` and `NotPromoted` by checking
if a type constructor is promoted using `isPromotedDataCon`.

Fixes #18020.

- - - - -
ce481361 by Ben Gamari at 2020-04-09T16:17:21-04:00
hadrian: Use --export-dynamic when linking iserv

As noticed in #17962, the make build system currently does this (see
3ce0e0ba) but the change was never ported to Hadrian.

- - - - -
fa66f143 by Ben Gamari at 2020-04-09T16:17:21-04:00
iserv: Don't pass --export-dynamic on FreeBSD

This is definitely a hack but it's probably the best we can do for now.
Hadrian does the right thing here by passing --export-dynamic only to
the linker.

- - - - -
39075176 by Ömer Sinan Ağacan at 2020-04-09T16:18:00-04:00
Fix CNF handling in compacting GC

Fixes #17937

Previously compacting GC simply ignored CNFs. This is mostly fine as
most (see "What about small compacts?" below) CNF objects don't have
outgoing pointers, and are "large" (allocated in large blocks) and large
objects are not moved or compacted.

However if we do GC *during* sharing-preserving compaction then the CNF
will have a hash table mapping objects that have been moved to the CNF
to their location in the CNF, to be able to preserve sharing.

This case is handled in the copying collector, in `scavenge_compact`,
where we evacuate hash table entries and then rehash the table.

Compacting GC ignored this case.

We now visit CNFs in all generations when threading pointers to the
compacted heap and thread hash table keys. A visited CNF is added to the
list `nfdata_chain`. After compaction is done, we re-visit the CNFs in
that list and rehash the tables.

The overhead is minimal: the list is static in `Compact.c`, and link
field is added to `StgCompactNFData` closure. Programs that don't use
CNFs should not be affected.

To test this CNF tests are now also run in a new way 'compacting_gc',
which just passes `-c` to the RTS, enabling compacting GC for the oldest
generation. Before this patch the result would be:

    Unexpected failures:
       compact_gc.run          compact_gc [bad exit code (139)] (compacting_gc)
       compact_huge_array.run  compact_huge_array [bad exit code (1)] (compacting_gc)

With this patch all tests pass. I can also pass `-c -DS` without any
failures.

What about small compacts? Small CNFs are still not handled by the
compacting GC. However so far I'm unable to write a test that triggers a
runtime panic ("update_fwd: unknown/strange object") by allocating a
small CNF in a compated heap. It's possible that I'm missing something
and it's not possible to have a small CNF.

NoFib Results:

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

Bumping numbers of nonsensical perf tests:

Metric Increase:
    T12150
    T12234
    T12425
    T13035
    T5837
    T6048

It's simply not possible for this patch to increase allocations, and
I've wasted enough time on these test in the past (see #17686). I think
these tests should not be perf tests, but for now I'll bump the numbers.

- - - - -
dce50062 by Sylvain Henry at 2020-04-09T16:18:44-04:00
Rts: show errno on failure (#18033)

- - - - -
045139f4 by Hécate at 2020-04-09T23:10:44-04:00
Add an example to liftIO and explain its purpose

- - - - -
101fab6e by Sebastian Graf at 2020-04-09T23:11:21-04:00
Special case `isConstraintKindCon` on `AlgTyCon`

Previously, the `tyConUnique` record selector would unfold into a huge
case expression that would be inlined in all call sites, such as the
`INLINE`-annotated `coreView`, see #18026. `constraintKindTyConKey` only
occurs as the `Unique` of an `AlgTyCon` anyway, so we can make the code
a lot more compact, but have to move it to GHC.Core.TyCon.

Metric Decrease:
    T12150
    T12234

- - - - -
f5212dfc by Sebastian Graf at 2020-04-09T23:11:57-04:00
DmdAnal: No need to attach a StrictSig to DataCon workers

In GHC.Types.Id.Make we were giving a strictness signature to every data
constructor wrapper Id that we weren't looking at in demand analysis
anyway. We used to use its CPR info, but that has its own CPR signature
now.

`Note [Data-con worker strictness]` then felt very out of place, so I
moved it to GHC.Core.DataCon.

- - - - -
75a185dc by Sylvain Henry at 2020-04-09T23:12:37-04:00
Hadrian: fix --summary

- - - - -
723062ed by Ömer Sinan Ağacan at 2020-04-10T09:18:14+03:00
testsuite: Move no_lint to the top level, tweak hie002

- We don't want to benchmark linting so disable lints in hie002 perf
  test

- Move no_lint to the top-level to be able to use it in tests other than
  those in `testsuite/tests/perf/compiler`.

- Filter out -dstg-lint in no_lint.

- hie002 allocation numbers on 32-bit are unstable, so skip it on 32-bit

Metric Decrease:
    hie002
    ManyConstructors
    T12150
    T12234
    T13035
    T1969
    T4801
    T9233
    T9961

- - - - -
bcafaa82 by Peter Trommler at 2020-04-10T19:29:33-04:00
Testsuite: mark T11531 fragile

The test depends on a link editor allowing undefined symbols in an ELF
shared object. This is the standard but it seems some distributions
patch their link editor. See the report by @hsyl20 in #11531.

Fixes #11531

- - - - -
0889f5ee by Takenobu Tani at 2020-04-12T11:44:52+09:00
testsuite: Fix comment for a language extension

[skip ci]

- - - - -
cd4f92b5 by Simon Peyton Jones at 2020-04-12T11:20:58-04:00
Significant refactor of Lint

This refactoring of Lint was triggered by #17923, which is
fixed by this patch.

The main change is this.  Instead of
   lintType :: Type -> LintM LintedKind
we now have
   lintType :: Type -> LintM LintedType

Previously, all of typeKind was effectively duplicate in lintType.
Moreover, since we have an ambient substitution, we still had to
apply the substition here and there, sometimes more than once. It
was all very tricky, in the end, and made my head hurt.

Now, lintType returns a fully linted type, with all substitutions
performed on it.  This is much simpler.

The same thing is needed for Coercions.  Instead of
  lintCoercion :: OutCoercion
               -> LintM (LintedKind, LintedKind,
                         LintedType, LintedType, Role)
we now have
  lintCoercion :: Coercion -> LintM LintedCoercion

Much simpler!  The code is shorter and less bug-prone.

There are a lot of knock on effects.  But life is now better.

Metric Decrease:
    T1969

- - - - -
0efaf301 by Josh Meredith at 2020-04-12T11:21:34-04:00
Implement extensible interface files

- - - - -
54ca66a7 by Ryan Scott at 2020-04-12T11:22:10-04:00
Use conLikeUserTyVarBinders to quantify field selector types

This patch:

1. Writes up a specification for how the types of top-level field
   selectors should be determined in a new section of the GHC User's
   Guide, and
2. Makes GHC actually implement that specification by using
   `conLikeUserTyVarBinders` in `mkOneRecordSelector` to preserve the
   order and specificity of type variables written by the user.

Fixes #18023.

- - - - -
35799dda by Ben Gamari at 2020-04-12T11:22:50-04:00
hadrian: Don't --export-dynamic on Darwin

When fixing #17962 I neglected to consider that --export-dynamic is only
supported on ELF platforms.

- - - - -
e8029816 by Alexis King at 2020-04-12T11:23:27-04:00
Add an INLINE pragma to Control.Category.>>>

This fixes #18013 by adding INLINE pragmas to both Control.Category.>>>
and GHC.Desugar.>>>. The functional change in this patch is tiny (just
two lines of pragmas!), but an accompanying Note explains in gory
detail what’s going on.

- - - - -
0da186c1 by Krzysztof Gogolewski at 2020-04-14T07:55:20-04:00
Change zipWith to zipWithEqual in a few places

- - - - -
074c1ccd by Andreas Klebinger at 2020-04-14T07:55:55-04:00
Small change to the windows ticker.

We already have a function to go from time to ms so use it.
Also expand on the state of timer resolution.

- - - - -
b69cc884 by Alp Mestanogullari at 2020-04-14T07:56:38-04:00
hadrian: get rid of unnecessary levels of nesting in source-dist

- - - - -
d0c3b069 by Julien Debon at 2020-04-14T07:57:16-04:00
doc (Foldable): Add examples to Data.Foldable

See #17929

- - - - -
5b08e0c0 by Ben Gamari at 2020-04-14T23:28:20-04:00
StgCRun: Enable unwinding only on Linux

It's broken on macOS due and SmartOS due to assembler differences
(#15207) so let's be conservative in enabling it. Also, refactor things
to make the intent clearer.

- - - - -
27cc2e7b by Ben Gamari at 2020-04-14T23:28:57-04:00
rts: Don't mark evacuate_large as inline

This function has two callsites and is quite large. GCC consequently
decides not to inline and warns instead. Given the situation, I can't
blame it. Let's just remove the inline specifier.

- - - - -
9853fc5e by Ben Gamari at 2020-04-14T23:29:48-04:00
base: Enable large file support for OFD locking impl.

Not only is this a good idea in general but this should also avoid
issue #17950 by ensuring that off_t is 64-bits.

- - - - -
7b41f21b by Matthew Pickering at 2020-04-14T23:30:24-04:00
Hadrian: Make -i paths absolute

The primary reason for this change is that ghcide does not work with
relative paths. It also matches what cabal and stack do, they always
pass absolute paths.

- - - - -
41230e26 by Daniel Gröber at 2020-04-14T23:31:01-04:00
Zero out pinned block alignment slop when profiling

The heap profiler currently cannot traverse pinned blocks because of
alignment slop. This used to just be a minor annoyance as the whole block
is accounted into a special cost center rather than the respective object's
CCS, cf. #7275. However for the new root profiler we would like to be able
to visit _every_ closure on the heap. We need to do this so we can get rid
of the current 'flip' bit hack in the heap traversal code.

Since info pointers are always non-zero we can in principle skip all the
slop in the profiler if we can rely on it being zeroed. This assumption
caused problems in the past though, commit a586b33f8e ("rts: Correct
handling of LARGE ARR_WORDS in LDV profiler"), part of !1118, tried to use
the same trick for BF_LARGE objects but neglected to take into account that
shrink*Array# functions don't ensure that slop is zeroed when not
compiling with profiling.

Later, commit 0c114c6599 ("Handle large ARR_WORDS in heap census (fix
as we will only be assuming slop is zeroed when profiling is on.

This commit also reduces the ammount of slop we introduce in the first
place by calculating the needed alignment before doing the allocation for
small objects where we know the next available address. For large objects
we don't know how much alignment we'll have to do yet since those details
are hidden behind the allocateMightFail function so there we continue to
allocate the maximum additional words we'll need to do the alignment.

So we don't have to duplicate all this logic in the cmm code we pull it
into the RTS allocatePinned function instead.

Metric Decrease:
    T7257
    haddock.Cabal
    haddock.base

- - - - -
15fa9bd6 by Daniel Gröber at 2020-04-14T23:31:01-04:00
rts: Expand and add more notes regarding slop

- - - - -
caf3f444 by Daniel Gröber at 2020-04-14T23:31:01-04:00
rts: allocatePinned: Fix confusion about word/byte units

- - - - -
c3c0f662 by Daniel Gröber at 2020-04-14T23:31:01-04:00
rts: Underline some Notes as is conventional

- - - - -
e149dea9 by Daniel Gröber at 2020-04-14T23:31:38-04:00
rts: Fix nomenclature in OVERWRITING_CLOSURE macros

The additional commentary introduced by commit 8916e64e5437 ("Implement
shrinkSmallMutableArray# and resizeSmallMutableArray#.") unfortunately got
this wrong. We set 'prim' to true in overwritingClosureOfs because we
_don't_ want to call LDV_recordDead().

The reason is because of this "inherently used" distinction made in the LDV
profiler so I rename the variable to be more appropriate.

- - - - -
1dd3d18c by Daniel Gröber at 2020-04-14T23:31:38-04:00
Remove call to LDV_RECORD_CREATE for array resizing

- - - - -
19de2fb0 by Daniel Gröber at 2020-04-14T23:31:38-04:00
rts: Assert LDV_recordDead is not called for inherently used closures

The comments make it clear LDV_recordDead should not be called for
inhererently used closures, so add an assertion to codify this fact.

- - - - -
0b934e30 by Ryan Scott at 2020-04-14T23:32:14-04:00
Bump template-haskell version to 2.17.0.0

This requires bumping the `exceptions` and `text` submodules to bring
in commits that bump their respective upper version bounds on
`template-haskell`.

Fixes #17645. Fixes #17696.

Note that the new `text` commit includes a fair number of additions
to the Haddocks in that library. As a result, Haddock has to do more
work during the `haddock.Cabal` test case, increasing the number of
allocations it requires. Therefore,

-------------------------
Metric Increase:
    haddock.Cabal
-------------------------

- - - - -
22cc8e51 by Ryan Scott at 2020-04-15T17:48:47-04:00
Fix #18052 by using pprPrefixOcc in more places

This fixes several small oversights in the choice of pretty-printing
function to use. Fixes #18052.

- - - - -
ec77b2f1 by Daniel Gröber at 2020-04-15T17:49:24-04:00
rts: ProfHeap: Fix wrong time in last heap profile sample

We've had this longstanding issue in the heap profiler, where the time of
the last sample in the profile is sometimes way off causing the rendered
graph to be quite useless for long runs.

It seems to me the problem is that we use mut_user_time() for the last
sample as opposed to getRTSStats(), which we use when calling heapProfile()
in GC.c.

The former is equivalent to getProcessCPUTime() but the latter does
some additional stuff:

    getProcessCPUTime() - end_init_cpu - stats.gc_cpu_ns -
    stats.nonmoving_gc_cpu_ns

So to fix this just use getRTSStats() in both places.

- - - - -
85fc32f0 by Sylvain Henry at 2020-04-17T12:45:25-04:00
Hadrian: fix dyn_o/dyn_hi rule (#17534)

- - - - -
bfde3b76 by Ryan Scott at 2020-04-17T12:46:02-04:00
Fix #18065 by fixing an InstCo oversight in Core Lint

There was a small thinko in Core Lint's treatment of `InstCo`
coercions that ultimately led to #18065. The fix: add an apostrophe.
That's it!

Fixes #18065.

Co-authored-by: Simon Peyton Jones <simonpj at microsoft.com>

- - - - -
a05348eb by Cale Gibbard at 2020-04-17T13:08:47-04:00
Change the fail operator argument of BindStmt to be a Maybe

Don't use noSyntaxExpr for it. There is no good way to defensively case
on that, nor is it clear one ought to do so.

- - - - -
79e27144 by John Ericson at 2020-04-17T13:08:47-04:00
Use trees that grow for rebindable operators for `<-` binds

Also add more documentation.

- - - - -
18bc16ed by Cale Gibbard at 2020-04-17T13:08:47-04:00
Use FailOperator in more places, define a couple datatypes (XBindStmtRn and XBindStmtTc) to help clarify the meaning of XBindStmt in the renamer and typechecker

- - - - -
84cc8394 by Simon Peyton Jones at 2020-04-18T13:20:29-04:00
Add a missing zonk in tcHsPartialType

I omitted a vital zonk when refactoring tcHsPartialType in
   commit 48fb3482f8cbc8a4b37161021e846105f980eed4
   Author: Simon Peyton Jones <simonpj at microsoft.com>
   Date:   Wed Jun 5 08:55:17 2019 +0100

   Fix typechecking of partial type signatures

This patch fixes it and adds commentary to explain why.

Fixes #18008

- - - - -
2ee96ac1 by Ben Gamari at 2020-04-18T13:21:05-04:00
gitlab-ci: Bump FreeBSD bootstrap compiler to 8.10.1

- - - - -
434312e5 by Ben Gamari at 2020-04-18T13:21:05-04:00
gitlab-ci: Enable FreeBSD job for so-labelled MRs

- - - - -
ddffb227 by Ben Gamari at 2020-04-18T13:21:05-04:00
gitlab-ci: Use rules syntax for conditional jobs

- - - - -
e2586828 by Ben Gamari at 2020-04-18T13:21:05-04:00
Bump hsc2hs submodule

- - - - -
15ab6cd5 by Ömer Sinan Ağacan at 2020-04-18T13:21:44-04:00
Improve prepForeignCall error reporting

Show parameters and description of the error code when ffi_prep_cif
fails.

This may be helpful for debugging #17018.

- - - - -
3ca52151 by Sylvain Henry at 2020-04-18T20:04:14+02:00
GHC.Core.Opt renaming

* GHC.Core.Op                  => GHC.Core.Opt
* GHC.Core.Opt.Simplify.Driver => GHC.Core.Opt.Driver
* GHC.Core.Opt.Tidy            => GHC.Core.Tidy
* GHC.Core.Opt.WorkWrap.Lib    => GHC.Core.Opt.WorkWrap.Utils

As discussed in:
 * https://mail.haskell.org/pipermail/ghc-devs/2020-April/018758.html
 * https://gitlab.haskell.org/ghc/ghc/issues/13009#note_264650

- - - - -
15312bbb by Sylvain Henry at 2020-04-18T20:04:46+02:00
Modules (#13009)

* SysTools
* Parser
* GHC.Builtin
* GHC.Iface.Recomp
* Settings

Update Haddock submodule

Metric Decrease:
    Naperian
    parsing001

- - - - -
eaed0a32 by Alexis King at 2020-04-19T03:16:44-04:00
Add missing addInScope call for letrec binders in OccurAnal

This fixes #18044, where a shadowed variable was incorrectly substituted
by the binder swap on the RHS of a floated-in letrec. This can only
happen when the uniques line up *just* right, so writing a regression
test would be very difficult, but at least the fix is small and
straightforward.

- - - - -
36882493 by Shayne Fletcher at 2020-04-20T04:36:43-04:00
Derive Ord instance for Extension

Metric Increase:
   T12150
   T12234

- - - - -
b43365ad by Simon Peyton Jones at 2020-04-20T04:37:20-04:00
Fix a buglet in redundant-constraint warnings

Ticket #18036 pointed out that we were reporting a redundant
constraint when it really really wasn't.

Turned out to be a buglet in the SkolemInfo for the
relevant implication constraint.  Easily fixed!

- - - - -
d5fae7da by Ömer Sinan Ağacan at 2020-04-20T14:39:28-04:00
Mark T12010 fragile on 32-bit

- - - - -
bca02fca by Adam Sandberg Ericsson at 2020-04-21T06:38:45-04:00
docs: drop note about not supporting shared libraries on unix systems

[skip ci]

- - - - -
6655f933 by Sylvain Henry at 2020-04-21T06:39:32-04:00
Use ParserFlags in GHC.Runtime.Eval (#17957)

Instead of passing `DynFlags` to functions such as `isStmt` and
`hasImport` in `GHC.Runtime.Eval` we pass `ParserFlags`. It's a much
simpler structure that can be created purely with `mkParserFlags'`.

- - - - -
70be0fbc by Sylvain Henry at 2020-04-21T06:39:32-04:00
GHC.Runtime: avoid DynFlags (#17957)

* add `getPlatform :: TcM Platform` helper
* remove unused `DynFlags` parameter from `emptyPLS`

- - - - -
35e43d48 by Sylvain Henry at 2020-04-21T06:39:32-04:00
Avoid DynFlags in Ppr code (#17957)

* replace `DynFlags` parameters with `SDocContext` parameters for a few
  Ppr related functions: `bufLeftRenderSDoc`, `printSDoc`,
  `printSDocLn`, `showSDocOneLine`.

* remove the use of `pprCols :: DynFlags -> Int` in Outputable. We
  already have the information via `sdocLineLength :: SDocContext ->
  Int`

- - - - -
ce5c2999 by Sylvain Henry at 2020-04-21T06:39:32-04:00
Avoid using sdocWithDynFlags (#17957)

Remove one use of `sdocWithDynFlags` from `GHC.CmmToLlvm.llvmCodeGen'`
and from `GHC.Driver.CodeOutput.profilingInitCode`

- - - - -
f2a98996 by Sylvain Henry at 2020-04-21T06:39:32-04:00
Avoid `sdocWithDynFlags` in `pprCLbl` (#17957)

* add a `DynFlags` parameter to `pprCLbl`
* put `maybe_underscore` and `pprAsmCLbl` in a `where` clause to avoid
  `DynFlags` parameters

- - - - -
747093b7 by Sylvain Henry at 2020-04-21T06:39:32-04:00
CmmToAsm DynFlags refactoring (#17957)

* Remove `DynFlags` parameter from `isDynLinkName`: `isDynLinkName` used
  to test the global `ExternalDynamicRefs` flag. Now we test it outside of
  `isDynLinkName`

* Add new fields into `NCGConfig`: current unit id, sse/bmi versions,
  externalDynamicRefs, etc.

* Replace many uses of `DynFlags` by `NCGConfig`

* Moved `BMI/SSE` datatypes into `GHC.Platform`

- - - - -
ffd7eef2 by Takenobu Tani at 2020-04-22T23:09:50-04:00
stg-spec: Modify file paths according to new module hierarchy

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

  * GHC/Stg/Syntax.hs       <= stgSyn/StgSyn.hs
  * GHC/Types/Literal.hs    <= basicTypes/Literal.hs
  * GHC/Types/CostCentre.hs <= profiling/CostCentre.hs

This patch also updates old file path [2]:

  * utils/genapply/Main.hs  <= utils/genapply/GenApply.hs

[1]: https://gitlab.haskell.org/ghc/ghc/-/wikis/Make-GHC-codebase-more-modular
[2]: commit 0cc4aad36f

[skip ci]

- - - - -
e8a5d81b by Jonathan DK Gibbons at 2020-04-22T23:10:28-04:00
Refactor the `MatchResult` type in the desugarer

This way, it does a better job of proving whether or not the fail operator is used.

- - - - -
dcb7fe5a by John Ericson at 2020-04-22T23:10:28-04:00
Remove panic in dsHandleMonadicFailure

Rework dsHandleMonadicFailure to be correct by construction instead of
using an unreachable panic.

- - - - -
cde23cd4 by John Ericson at 2020-04-22T23:10:28-04:00
Inline `adjustMatchResult`

It is just `fmap`

- - - - -
72cb6bcc by John Ericson at 2020-04-22T23:10:28-04:00
Generalize type of `matchCanFail`

- - - - -
401f7bb3 by John Ericson at 2020-04-22T23:10:28-04:00
`MatchResult'` -> `MatchResult`

Inline `MatchResult` alias accordingly.

- - - - -
6c9fae23 by Alexis King at 2020-04-22T23:11:12-04:00
Mark DataCon wrappers CONLIKE

Now that DataCon wrappers don’t inline until phase 0 (see commit
b78cc64e923716ac0512c299f42d4d0012306c05), it’s important that
case-of-known-constructor and RULE matching be able to see saturated
applications of DataCon wrappers in unfoldings. Making them conlike is a
natural way to do it, since they are, in fact, precisely the sort of
thing the CONLIKE pragma exists to solve.

Fixes #18012.

This also bumps the version of the parsec submodule to incorporate a
patch that avoids a metric increase on the haddock perf tests. The
increase was not really a flaw in this patch, as parsec was implicitly
relying on inlining heuristics. The patch to parsec just adds some
INLINABLE pragmas, and we get a nice performance bump out of it (well
beyond the performance we lost from this patch).

Metric Decrease:
    T12234
    WWRec
    haddock.Cabal
    haddock.base
    haddock.compiler

- - - - -
48b8951e by Roland Senn at 2020-04-22T23:11:51-04:00
Fix tab-completion for :break (#17989)

In tab-completion for the `:break` command, only those
identifiers should be shown, that are accepted in the
`:break` command. Hence these identifiers must be

- defined in an interpreted module
- top-level
- currently in scope
- listed in a `ModBreaks` value as a possible breakpoint.

The identifiers my be qualified or unqualified.

To get all possible top-level breakpoints for tab-completeion
with the correct qualification do:

1. Build the  list called `pifsBreaks` of all pairs of
(Identifier, module-filename) from the `ModBreaks` values.
Here all identifiers are unqualified.

2. Build the list called `pifInscope` of all pairs of
(Identifiers, module-filename) with identifiers from
the `GlobalRdrEnv`. Take only those identifiers that are
in scope and have the  correct prefix.
Here the identifiers may be qualified.

3. From the `pifInscope` list seclect all pairs that can be
found in the `pifsBreaks` list, by comparing only the
unqualified part of the identifier.
The remaining identifiers can be used for tab-completion.

This ensures, that we show only identifiers, that can be used
in a `:break` command.

- - - - -
34a45ee6 by Peter Trommler at 2020-04-22T23:12:27-04:00
PPC NCG: Add DWARF constants and debug labels

Fixes #11261

- - - - -
ffde2348 by Simon Peyton Jones at 2020-04-22T23:13:06-04:00
Do eager instantation in terms

This patch implements eager instantiation, a small but critical change
to the type inference engine, #17173.  The main change is this:

  When inferring types, always return an instantiated type
  (for now, deeply instantiated; in future shallowly instantiated)

There is more discussion in
https://www.tweag.io/posts/2020-04-02-lazy-eager-instantiation.html

There is quite a bit of refactoring in this patch:

* The ir_inst field of GHC.Tc.Utils.TcType.InferResultk
  has entirely gone.  So tcInferInst and tcInferNoInst have collapsed
  into tcInfer.

* Type inference of applications, via tcInferApp and
  tcInferAppHead, are substantially refactored, preparing
  the way for Quick Look impredicativity.

* New pure function GHC.Tc.Gen.Expr.collectHsArgs and applyHsArgs
  are beatifully dual.  We can see the zipper!

* GHC.Tc.Gen.Expr.tcArgs is now much nicer; no longer needs to return
  a wrapper

* In HsExpr, HsTypeApp now contains the the actual type argument,
  and is used in desugaring, rather than putting it in a mysterious
  wrapper.

* I struggled a bit with good error reporting in
  Unify.matchActualFunTysPart. It's a little bit simpler than before,
  but still not great.

Some smaller things

* Rename tcPolyExpr --> tcCheckExpr
         tcMonoExpr --> tcLExpr
* tcPatSig moves from GHC.Tc.Gen.HsType to GHC.Tc.Gen.Pat

Metric Decrease:
    T9961

Reduction of 1.6% in comiler allocation on T9961, I think.

- - - - -
6f84aca3 by Ben Gamari at 2020-04-22T23:13:43-04:00
rts: Ensure that sigaction structs are initialized

I noticed these may have uninitialized fields when looking into #18037.
The reporter says that zeroing them doesn't fix the MSAN failures they
observe but zeroing them is the right thing to do regardless.

- - - - -
c29f0fa6 by Andreas Klebinger at 2020-04-22T23:14:21-04:00
Add "ddump-cmm-opt" as alias for "ddump-opt-cmm".

- - - - -
4b4a8b60 by Ben Gamari at 2020-04-22T23:14:57-04:00
llvmGen: Remove -fast-llvm flag

Issue #18076 drew my attention to the undocumented `-fast-llvm` flag for
the LLVM code generator introduced in
22733532171330136d87533d523f565f2a4f102f. Speaking to Moritz about this,
the motivation for this flag was to avoid potential incompatibilities
between LLVM and the assembler/linker toolchain by making LLVM
responsible for machine-code generation.

Unfortunately, this cannot possibly work: the LLVM backend's mangler
performs a number of transforms on the assembler generated by LLVM that
are necessary for correctness. These are currently:

 * mangling Haskell functions' symbol types to be `object` instead of
   `function` on ELF platforms (necessary for tables-next-to-code)
 * mangling AVX instructions to ensure that we don't assume alignment
   (which LLVM otherwise does)
 * mangling Darwin's  subsections-via-symbols directives

Given that these are all necessary I don't believe that we can support
`-fast-llvm`. Let's rather remove it.

- - - - -
831b6642 by Moritz Angermann at 2020-04-22T23:15:33-04:00
Fix build warning; add more informative information to the linker; fix linker for empty sections

- - - - -
c409961a by Ryan Scott at 2020-04-22T23:16:12-04:00
Update commentary and slightly refactor GHC.Tc.Deriv.Infer

There was some out-of-date commentary in `GHC.Tc.Deriv.Infer` that
has been modernized. Along the way, I removed the `bad` constraints
in `simplifyDeriv`, which did not serve any useful purpose (besides
being printed in debugging output).

Fixes #18073.

- - - - -
125aa2b8 by Ömer Sinan Ağacan at 2020-04-22T23:16:51-04:00
Remove leftover comment in tcRnModule', redundant bind

The code for the comment was moved in dc8c03b2a5c but the comment was
forgotten.

- - - - -
8ea37b01 by Sylvain Henry at 2020-04-22T23:17:34-04:00
RTS: workaround a Linux kernel bug in timerfd

Reading a timerfd may return 0: https://lkml.org/lkml/2019/8/16/335.

This is currently undocumented behavior and documentation "won't happen
anytime soon" (https://lkml.org/lkml/2020/2/13/295).

With this patch, we just ignore the result instead of crashing. It may
fix #18033 but we can't be sure because we don't have enough
information.

See also this discussion about the kernel bug:
https://github.com/Azure/sonic-swss-common/pull/302/files/1f070e7920c2e5d63316c0105bf4481e73d72dc9

- - - - -
cd8409c2 by Ryan Scott at 2020-04-23T11:39:24-04:00
Create di_scoped_tvs for associated data family instances properly

See `Note [Associated data family instances and di_scoped_tvs]` in
`GHC.Tc.TyCl.Instance`, which explains all of the moving parts.

Fixes #18055.

- - - - -
339e8ece by Ben Gamari at 2020-04-23T11:40:02-04:00
hadrian/ghci: Allow arguments to be passed to GHCi

Previously the arguments passed to hadrian/ghci were passed both to
`hadrian` and GHCi. This is rather odd given that there are essentially
not arguments in the intersection of the two. Let's just pass them to
GHCi; this allows `hadrian/ghci -Werror`.

- - - - -
5946c85a by Ben Gamari at 2020-04-23T11:40:38-04:00
testsuite: Don't attempt to read .std{err,out} files if they don't exist

Simon reports that he was previously seeing framework failures due to
an attempt to read the non-existing T13456.stderr. While I don't know
exactly what this is due to, it does seem like a non-existing
.std{out,err} file should be equivalent to an empty file. Teach the
testsuite driver to treat it as such.

- - - - -
c42754d5 by John Ericson at 2020-04-23T18:32:43-04:00
Trees That Grow refactor for `ConPat` and `CoPat`

- `ConPat{In,Out}` -> `ConPat`

- `CoPat` -> `XPat (CoPat ..)`

Note that `GHC.HS.*` still uses `HsWrap`, but only when `p ~ GhcTc`.
After this change, moving the type family instances out of `GHC.HS.*` is
sufficient to break the cycle.

Add XCollectPat class to decide how binders are collected from XXPat based on the pass.

Previously we did this with IsPass, but that doesn't work for Haddock's
DocNameI, and the constraint doesn't express what actual distinction is being
made. Perhaps a class for collecting binders more generally is in order, but we
haven't attempted this yet.

Pure refactor of code around ConPat

 - InPat/OutPat synonyms removed

 - rename several identifiers

 - redundant constraints removed

 - move extension field in ConPat to be first

 - make ConPat use record syntax more consistently

Fix T6145 (ConPatIn became ConPat)

Add comments from SPJ.

Add comment about haddock's use of CollectPass.

Updates haddock submodule.

- - - - -
72da0c29 by mniip at 2020-04-23T18:33:21-04:00
Add :doc to GHC.Prim

- - - - -
2c23e2e3 by mniip at 2020-04-23T18:33:21-04:00
Include docs for non-primop entries in primops.txt as well

- - - - -
0ac29c88 by mniip at 2020-04-23T18:33:21-04:00
GHC.Prim docs: note and test

- - - - -
b0fbfc75 by John Ericson at 2020-04-24T12:07:14-04:00
Switch order on `GhcMake.IsBoot`

In !1798 we were requested to replace many `Bool`s with this data type.
But those bools had `False` meaning `NotBoot`, so the `Ord` instance
would be flipped if we use this data-type as-is.

Since the planned formally-`Bool` occurrences vastly outnumber the
current occurrences, we figured it would be better to conform the `Ord`
instance to how the `Bool` is used now, fixing any issues, rather than
fix them currently with the bigger refactor later in !1798. That way,
!1798 can be a "pure" refactor with no behavioral changes.

- - - - -
af332442 by Sylvain Henry at 2020-04-26T13:55:14-04:00
Modules: Utils and Data (#13009)

Update Haddock submodule

Metric Increase:
   haddock.compiler

- - - - -
cd4434c8 by Sylvain Henry at 2020-04-26T13:55:16-04:00
Fix misleading Ptr phantom type in SerializedCompact (#15653)

- - - - -
22bf5c73 by Ömer Sinan Ağacan at 2020-04-26T13:55:22-04:00
Tweak includes in non-moving GC headers

We don't use hash tables in non-moving GC so remove the includes.

This breaks Compact.c as existing includes no longer include Hash.h, so
include Hash.h explicitly in Compact.c.

- - - - -
99823ed2 by Sylvain Henry at 2020-04-27T20:24:46-04:00
TH: fix Show/Eq/Ord instances for Bytes (#16457)

We shouldn't compare pointer values but the actual bytes.

- - - - -
c62271a2 by Alp Mestanogullari at 2020-04-27T20:25:33-04:00
hadrian: always capture both stdout and stderr when running a builder fails

The idea being that when a builder('s command) fails, we quite likely want to
have all the information available to figure out why. Depending on the builder
_and_ the particular problem, the useful bits of information can be printed
on stdout or stderr.

We accomplish this by defining a simple wrapper for Shake's `cmd` function,
that just _always_ captures both streams in case the command returns a non-zero
exit code, and by using this wrapper everywhere in `hadrian/src/Builder.hs`.

Fixes #18089.

- - - - -
4b9764db by Ryan Scott at 2020-04-28T15:40:04-04:00
Define a Quote IO instance

Fixes #18103.

- - - - -
518a63d4 by Ryan Scott at 2020-04-28T15:40:42-04:00
Make boxed 1-tuples have known keys

Unlike other tuples, which use special syntax and are "known" by way
of a special `isBuiltInOcc_maybe` code path, boxed 1-tuples do not
use special syntax. Therefore, in order to make sure that the
internals of GHC are aware of the `data Unit a = Unit a` definition
in `GHC.Tuple`, we give `Unit` known keys. For the full details, see
`Note [One-tuples] (Wrinkle: Make boxed one-tuple names have known keys)`
in `GHC.Builtin.Types`.

Fixes #18097.

- - - - -
2cfc4ab9 by Sylvain Henry at 2020-04-30T01:56:56-04:00
Document backpack fields in DynFlags

- - - - -
10a2ba90 by Sylvain Henry at 2020-04-30T01:56:56-04:00
Refactor UnitInfo

* Rename InstalledPackageInfo into GenericUnitInfo

The name InstalledPackageInfo is only kept for alleged backward
compatibility reason in Cabal. ghc-boot has its own stripped down copy
of this datatype but it doesn't need to keep the name. Internally we
already use type aliases (UnitInfo in GHC, PackageCacheFormat in
ghc-pkg).

* Rename UnitInfo fields: add "unit" prefix and fix misleading names

* Add comments on every UnitInfo field

* Rename SourcePackageId into PackageId

"Package" already indicates that it's a "source package". Installed
package components are called units.

Update Haddock submodule

- - - - -
69562e34 by Sylvain Henry at 2020-04-30T01:56:56-04:00
Remove unused `emptyGenericUnitInfo`

- - - - -
9e2c8e0e by Sylvain Henry at 2020-04-30T01:56:56-04:00
Refactor UnitInfo load/store from databases

Converting between UnitInfo stored in package databases and UnitInfo as
they are used in ghc-pkg and ghc was done in a very convoluted way (via
BinaryStringRep and DbUnitModuleRep type classes using fun deps, etc.).
It was difficult to understand and even more to modify (I wanted to
try to use a GADT for UnitId but fun deps got in the way).

The new code uses much more straightforward functions to convert between
the different representations. Much simpler.

- - - - -
ea717aa4 by Sylvain Henry at 2020-04-30T01:56:56-04:00
Factorize mungePackagePaths code

This patch factorizes the duplicated code used in ghc-pkg and in GHC to
munge package paths/urls.

It also fixes haddock-html munging in GHC (allowed to be either a file
or a url) to mimic ghc-pkg behavior.

- - - - -
10d15f1e by Sylvain Henry at 2020-04-30T01:56:56-04:00
Refactoring unit management code

Over the years the unit management code has been modified a lot to keep
up with changes in Cabal (e.g. support for several library components in
the same package), to integrate BackPack, etc. I found it very hard to
understand as the terminology wasn't consistent, was referring to past
concepts, etc.

The terminology is now explained as clearly as I could in the Note
"About Units" and the code is refactored to reflect it.

-------------------

Many names were misleading: UnitId is not an Id but could be a virtual
unit (an indefinite one instantiated on the fly), IndefUnitId
constructor may contain a definite instantiated unit, etc.

   * Rename IndefUnitId into InstantiatedUnit
   * Rename IndefModule into InstantiatedModule
   * Rename UnitId type into Unit
   * Rename IndefiniteUnitId constructor into VirtUnit
   * Rename DefiniteUnitId constructor into RealUnit
   * Rename packageConfigId into mkUnit
   * Rename getPackageDetails into unsafeGetUnitInfo
   * Rename InstalledUnitId into UnitId

Remove references to misleading ComponentId: a ComponentId is just an
indefinite unit-id to be instantiated.

   * Rename ComponentId into IndefUnitId
   * Rename ComponentDetails into UnitPprInfo
   * Fix display of UnitPprInfo with empty version: this is now used for
     units dynamically generated by BackPack

Generalize several types (Module, Unit, etc.) so that they can be used
with different unit identifier types: UnitKey, UnitId, Unit, etc.

   * GenModule: Module, InstantiatedModule and InstalledModule are now
     instances of this type
   * Generalize DefUnitId, IndefUnitId, Unit, InstantiatedUnit,
     PackageDatabase

Replace BackPack fake "hole" UnitId by a proper HoleUnit constructor.

Add basic support for UnitKey. They should be used more in the future to
avoid mixing them up with UnitId as we do now.

Add many comments.

Update Haddock submodule

- - - - -
8bfb0219 by Sylvain Henry at 2020-04-30T01:56:56-04:00
Unit: split and rename modules

Introduce GHC.Unit.* hierarchy for everything concerning units, packages
and modules.

Update Haddock submodule

- - - - -
71484b09 by Alexis King at 2020-04-30T01:57:35-04:00
Allow block arguments in arrow control operators

Arrow control operators have their own entries in the grammar, so they
did not cooperate with BlockArguments. This was just a minor oversight,
so this patch adjusts the grammar to add the desired behavior.

fixes #18050

- - - - -
a48cd2a0 by Alexis King at 2020-04-30T01:57:35-04:00
Allow LambdaCase to be used as a command in proc notation

- - - - -
f4d3773c by Alexis King at 2020-04-30T01:57:35-04:00
Document BlockArguments/LambdaCase support in arrow notation

- - - - -
5bdfdd13 by Simon Peyton Jones at 2020-04-30T01:58:15-04:00
Add tests for #17873

- - - - -
19b701c2 by Simon Peyton Jones at 2020-04-30T07:30:13-04:00
Mark rule args as non-tail-called

This was just an omission...b I'd failed to call markAllNonTailCall on
rule args.  I think this bug has been here a long time, but it's quite
hard to trigger.

Fixes #18098

- - - - -
014ef4a3 by Matthew Pickering at 2020-04-30T07:30:50-04:00
Hadrian: Improve tool-args command to support more components

There is a new command to hadrian, tool:path/to/file.hs, which returns
the options needed to compile that file in GHCi.

This is now used in the ghci script with argument `ghc/Main.hs` but its
main purpose is to support the new multi-component branch of ghcide.

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

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

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

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

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

(cherry picked from commit 2fa79119570b358a4db61446396889b8260d7957)

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

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

Other changes:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Fixes #18049.

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

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

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

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

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

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

closes #18112

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

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

Moreover a debug-trace might print it out.

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

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

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

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

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

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

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

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

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

Make GHC.Exts "not-home" for haddock

Metric Decrease:
   haddock.base

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

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

Commit e3c374cc5bd7eb49649b9f507f9f7740697e3f70 ended up
fixing quite a few bugs:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Updates haddock submodule

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

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

Fixes #18127.

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

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

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

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

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

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

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

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

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

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

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

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

See #17929

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

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

See #17929

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

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

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

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

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

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

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

 - Use type synnonym to convey the intent like elsewhere.

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

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

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

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

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

Fixes #18120

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

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

- - - - -
9d97f4b5 by nineonine at 2020-05-08T15:30:03-04:00
Add test for #16167

- - - - -
aa318338 by Ryan Scott at 2020-05-08T15:30:04-04:00
Bump exceptions submodule so that dist-boot is .gitignore'd

`exceptions` is a stage-0 boot library as of commit
30272412fa437ab8e7a8035db94a278e10513413, which means that building
`exceptions` in a GHC tree will generate a `dist-boot` directory.
However, this directory was not specified in `exceptions`'
`.gitignore` file, which causes it to dirty up the current `git`
working directory.

Accordingly, this bumps the `exceptions` submodule to commit
ghc/packages/exceptions at 23c0b8a50d7592af37ca09beeec16b93080df98f,
which adds `dist-boot` to the `.gitignore` file.

- - - - -
ea86360f by Ömer Sinan Ağacan at 2020-05-08T15:30:30-04:00
Linker.c: initialize n_symbols of ObjectCode with other fields

- - - - -
951c1fb0 by Sylvain Henry at 2020-05-09T21:46:38-04:00
Fix unboxed-sums GC ptr-slot rubbish value (#17791)

This patch allows boot libraries to use unboxed sums without implicitly
depending on `base` package because of `absentSumFieldError`.

See updated Note [aBSENT_SUM_FIELD_ERROR_ID] in GHC.Core.Make

- - - - -
b352d63c by Ben Gamari at 2020-05-09T21:47:14-04:00
rts: Make non-existent linker search path merely a warning

As noted in #18105, previously this resulted in a rather intrusive error
message. This is in contrast to the general expectation that search
paths are merely places to look, not places that must exist.

Fixes #18105.

- - - - -
cf4f1e2f by Ben Gamari at 2020-05-13T02:02:33-04:00
rts/CNF: Fix fixup comparison function

Previously we would implicitly convert the difference between two words
to an int, resulting in an integer overflow on 64-bit machines.

Fixes #16992

- - - - -
a03da9bf by Ömer Sinan Ağacan at 2020-05-13T02:03:16-04:00
Pack some of IdInfo fields into a bit field

This reduces residency of compiler quite a bit on some programs.
Example stats when building T10370:

Before:

   2,871,242,832 bytes allocated in the heap
   4,693,328,008 bytes copied during GC
      33,941,448 bytes maximum residency (276 sample(s))
         375,976 bytes maximum slop
              83 MiB total memory in use (0 MB lost due to fragmentation)

After:

   2,858,897,344 bytes allocated in the heap
   4,629,255,440 bytes copied during GC
      32,616,624 bytes maximum residency (278 sample(s))
         314,400 bytes maximum slop
              80 MiB total memory in use (0 MB lost due to fragmentation)

So -3.9% residency, -1.3% bytes copied and -0.4% allocations.

Fixes #17497

Metric Decrease:
    T9233
    T9675

- - - - -
670c3e5c by Ben Gamari at 2020-05-13T02:03:54-04:00
get-win32-tarballs: Fix base URL

Revert a change previously made for testing purposes.

- - - - -
8ad8dc41 by Ben Gamari at 2020-05-13T02:03:54-04:00
get-win32-tarballs: Improve diagnostics output

- - - - -
8c0740b7 by Simon Jakobi at 2020-05-13T02:04:33-04:00
docs: Add examples for Data.Semigroup.Arg{Min,Max}

Context: #17153

- - - - -
cb22348f by Ben Gamari at 2020-05-13T02:05:11-04:00
Add few cleanups of the CAF logic

Give the NameSet of non-CAFfy names a proper newtype to distinguish it
from all of the other NameSets floating about.

- - - - -
90e38b81 by Emeka Nkurumeh at 2020-05-13T02:05:51-04:00
fix printf warning when using with ghc with clang on mingw
- - - - -
86d8ac22 by Sebastian Graf at 2020-05-13T02:06:29-04:00
CprAnal: Don't attach CPR sigs to expandable bindings (#18154)

Instead, look through expandable unfoldings in `cprTransform`.
See the new Note [CPR for expandable unfoldings]:

```
Long static data structures (whether top-level or not) like

  xs = x1 : xs1
  xs1 = x2 : xs2
  xs2 = x3 : xs3

should not get CPR signatures, because they

  * Never get WW'd, so their CPR signature should be irrelevant after analysis
    (in fact the signature might even be harmful for that reason)
  * Would need to be inlined/expanded to see their constructed product
  * Recording CPR on them blows up interface file sizes and is redundant with
    their unfolding. In case of Nested CPR, this blow-up can be quadratic!

But we can't just stop giving DataCon application bindings the CPR property,
for example

  fac 0 = 1
  fac n = n * fac (n-1)

fac certainly has the CPR property and should be WW'd! But FloatOut will
transform the first clause to

  lvl = 1
  fac 0 = lvl

If lvl doesn't have the CPR property, fac won't either. But lvl doesn't have a
CPR signature to extrapolate into a CPR transformer ('cprTransform'). So
instead we keep on cprAnal'ing through *expandable* unfoldings for these arity
0 bindings via 'cprExpandUnfolding_maybe'.

In practice, GHC generates a lot of (nested) TyCon and KindRep bindings, one
for each data declaration. It's wasteful to attach CPR signatures to each of
them (and intractable in case of Nested CPR).
```

Fixes #18154.

- - - - -
e34bf656 by Ben Gamari at 2020-05-13T02:07:08-04:00
users-guide: Add discussion of shared object naming

Fixes #18074.

- - - - -
5d0f2445 by Ben Gamari at 2020-05-13T02:07:47-04:00
testsuite: Print sign of performance changes

Executes the minor formatting change in the tabulated performance
changes suggested in #18135.

- - - - -
9e4b981f by Ben Gamari at 2020-05-13T02:08:24-04:00
testsuite: Add testcase for #18129

- - - - -
266310c3 by Ivan-Yudin at 2020-05-13T02:09:03-04:00
doc: Reformulate the opening paragraph of Ch. 4 in User's guide

Removes mentioning of Hugs
(it is not helpful for new users anymore).

Changes the wording for the rest of the paragraph.

Fixes #18132.

- - - - -
55e35c0b by Baldur Blöndal at 2020-05-13T20:02:48-04:00
Predicate, Equivalence derive via `.. -> a -> All'

- - - - -
d7e0b57f by Alp Mestanogullari at 2020-05-13T20:03:30-04:00
hadrian: add a --freeze2 option to freeze stage 1 and 2

- - - - -
d880d6b2 by Artem Pelenitsyn at 2020-05-13T20:04:11-04:00
Don't reload environment files on every setSessionDynFlags

Makes `interpretPackageEnv` (which loads envirinment files) a part of
`parseDynamicFlags` (parsing command-line arguments, which is typically
done once) instead of `setSessionDynFlags` (which is typically called
several times). Making several (transitive) calls to `interpretPackageEnv`,
as before, caused #18125 #16318, which should be fixed now.

- - - - -
102cfd67 by Ryan Scott at 2020-05-13T20:04:46-04:00
Factor out HsPatSigType for pat sigs/RULE term sigs (#16762)

This implements chunks (2) and (3) of
https://gitlab.haskell.org/ghc/ghc/issues/16762#note_270170. Namely,
it introduces a dedicated `HsPatSigType` AST type, which represents
the types that can appear in pattern signatures and term-level `RULE`
binders. Previously, these were represented with `LHsSigWcType`.
Although `LHsSigWcType` is isomorphic to `HsPatSigType`, the intended
semantics of the two types are slightly different, as evidenced by
the fact that they have different code paths in the renamer and
typechecker.

See also the new `Note [Pattern signature binders and scoping]` in
`GHC.Hs.Types`.

- - - - -
b17574f7 by Hécate at 2020-05-13T20:05:28-04:00
fix(documentation): Fix the RST links to GHC.Prim

- - - - -
df021fb1 by Baldur Blöndal at 2020-05-13T20:06:06-04:00
Document (->) using inferred quantification for its runtime representations.

Fixes #18142.

- - - - -
1a93ea57 by Takenobu Tani at 2020-05-13T20:06:54-04:00
Tweak man page for ghc command

This commit updates the ghc command's man page as followings:

* Enable `man_show_urls` to show URL addresses in the `DESCRIPTION`
section of ghc.rst, because sphinx currently removes hyperlinks
for man pages.

* Add a `SEE ALSO` section to point to the GHC homepage

- - - - -
a951e1ba by Takenobu Tani at 2020-05-13T20:07:37-04:00
GHCi: Add link to the user's guide in help message

This commit adds a link to the user's guide in ghci's
`:help` message.

Newcomers could easily reach to details of ghci.

- - - - -
404581ea by Jeff Happily at 2020-05-13T20:08:15-04:00
Handle single unused import

- - - - -
1c999e5d by Ben Gamari at 2020-05-13T20:09:07-04:00
Ensure that printMinimalImports closes handle

Fixes #18166.

- - - - -
c9f5a8f4 by Ben Gamari at 2020-05-13T20:09:51-04:00
hadrian: Tell testsuite driver about LLVM availability

This reflects the logic present in the Make build system into Hadrian.

Fixes #18167.

- - - - -
c05c0659 by Simon Jakobi at 2020-05-14T03:31:21-04:00
Improve some folds over Uniq[D]FM

* Replace some non-deterministic lazy folds with
  strict folds.
* Replace some O(n log n) folds in deterministic order
  with O(n) non-deterministic folds.
* Replace some folds with set-operations on the underlying
  IntMaps.

This reduces max residency when compiling
`nofib/spectral/simple/Main.hs` with -O0 by about 1%.

Maximum residency when compiling Cabal also seems reduced on the
order of 3-9%.

- - - - -
477f13bb by Simon Jakobi at 2020-05-14T03:31:58-04:00
Use Data.IntMap.disjoint

Data.IntMap gained a dedicated `disjoint` function in containers-0.6.2.1.

This patch applies this function where appropriate in hopes of modest
compiler performance improvements.

Closes #16806.

- - - - -
e9c0110c by Ben Gamari at 2020-05-14T12:25:53-04:00
IdInfo: Add reference to bitfield-packing ticket

- - - - -
9bd20e83 by Sebastian Graf at 2020-05-15T10:42:09-04:00
DmdAnal: Improve handling of precise exceptions

This patch does two things: Fix possible unsoundness in what was called
the "IO hack" and implement part 2.1 of the "fixing precise exceptions"
plan in
https://gitlab.haskell.org/ghc/ghc/wikis/fixing-precise-exceptions,
which, in combination with !2956, supersedes !3014 and !2525.

**IO hack**

The "IO hack" (which is a fallback to preserve precise exceptions
semantics and thus soundness, rather than some smart thing that
increases precision) is called `exprMayThrowPreciseException` now.
I came up with two testcases exemplifying possible unsoundness (if
twisted enough) in the old approach:

- `T13380d`: Demonstrating unsoundness of the "IO hack" when resorting
             to manual state token threading and direct use of primops.
             More details below.
- `T13380e`: Demonstrating unsoundness of the "IO hack" when we have
             Nested CPR. Not currently relevant, as we don't have Nested
             CPR yet.
- `T13380f`: Demonstrating unsoundness of the "IO hack" for safe FFI
             calls.

Basically, the IO hack assumed that precise exceptions can only be
thrown from a case scrutinee of type `(# State# RealWorld, _ #)`. I
couldn't come up with a program using the `IO` abstraction that violates
this assumption. But it's easy to do so via manual state token threading
and direct use of primops, see `T13380d`. Also similar code might be
generated by Nested CPR in the (hopefully not too) distant future, see
`T13380e`. Hence, we now have a more careful test in `forcesRealWorld`
that passes `T13380{d,e}` (and will hopefully be robust to Nested CPR).

**Precise exceptions**

In #13380 and #17676 we saw that we didn't preserve precise exception
semantics in demand analysis. We fixed that with minimal changes in
!2956, but that was terribly unprincipled.

That unprincipledness resulted in a loss of precision, which is tracked
by these new test cases:

- `T13380b`: Regression in dead code elimination, because !2956 was too
             syntactic about `raiseIO#`
- `T13380c`: No need to apply the "IO hack" when the IO action may not
             throw a precise exception (and the existing IO hack doesn't
             detect that)

Fixing both issues in !3014 turned out to be too complicated and had
the potential to regress in the future. Hence we decided to only fix
`T13380b` and augment the `Divergence` lattice with a new middle-layer
element, `ExnOrDiv`, which means either `Diverges` (, throws an
imprecise exception) or throws a *precise* exception.

See the wiki page on Step 2.1 for more implementational details:
https://gitlab.haskell.org/ghc/ghc/wikis/fixing-precise-exceptions#dead-code-elimination-for-raiseio-with-isdeadenddiv-introducing-exnordiv-step-21

- - - - -
568d7279 by Ben Gamari at 2020-05-15T10:42:46-04:00
GHC.Cmm.Opt: Handle MO_XX_Conv

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

Fixes #18141.

- - - - -
5bcf8606 by Ryan Scott at 2020-05-17T08:46:38-04:00
Remove duplicate Note [When to print foralls] in GHC.Core.TyCo.Ppr

There are two different Notes named `[When to print foralls]`. The
most up-to-date one is in `GHC.Iface.Type`, but there is a second
one in `GHC.Core.TyCo.Ppr`. The latter is less up-to-date, as it was
written before GHC switched over to using ifaces to pretty-print
types. I decided to just remove the latter and replace it with a
reference to the former.

[ci skip]

- - - - -
55f0e783 by Fumiaki Kinoshita at 2020-05-21T12:10:44-04:00
base: Add Generic instances to various datatypes under GHC.*

* GHC.Fingerprint.Types: Fingerprint
* GHC.RTS.Flags: GiveGCStats, GCFlags, ConcFlags, DebugFlags, CCFlags, DoHeapProfile, ProfFlags, DoTrace, TraceFlags, TickyFlags, ParFlags and RTSFlags
* GHC.Stats: RTSStats and GCStats
* GHC.ByteOrder: ByteOrder
* GHC.Unicode: GeneralCategory
* GHC.Stack.Types: SrcLoc

Metric Increase:
    haddock.base

- - - - -
a9311cd5 by Gert-Jan Bottu at 2020-05-21T12:11:31-04:00
Explicit Specificity

Implementation for Ticket #16393.
Explicit specificity allows users to manually create inferred type variables,
by marking them with braces.
This way, the user determines which variables can be instantiated through
visible type application.

The additional syntax is included in the parser, allowing users to write
braces in type variable binders (type signatures, data constructors etc).
This information is passed along through the renamer and verified in the
type checker.
The AST for type variable binders, data constructors, pattern synonyms,
partial signatures and Template Haskell has been updated to include the
specificity of type variables.

Minor notes:
- Bumps haddock submodule
- Disables pattern match checking in GHC.Iface.Type with GHC 8.8

- - - - -
24e61aad by Ben Price at 2020-05-21T12:12:17-04:00
Lint should say when it is checking a rule

It is rather confusing that when lint finds an error in a rule attached
to a binder, it reports the error as in the RHS, not the rule:
  ...
  In the RHS of foo

We add a clarifying line:
  ...
  In the RHS of foo
  In a rule attached to foo

The implication that the rule lives inside the RHS is a bit odd, but
this niggle is already present for unfoldings, whose pattern we are
following.

- - - - -
78c6523c by Ben Gamari at 2020-05-21T12:13:01-04:00
nonmoving: Optimise the write barrier

- - - - -
13f6c9d0 by Andreas Klebinger at 2020-05-21T12:13:45-04:00
Refactor linear reg alloc to remember past assignments.

When assigning registers we now first try registers we
assigned to in the past, instead of picking the "first"
one.

This is in extremely helpful when dealing with loops for
which variables are dead for part of the loop.

This is important for patterns like this:

        foo = arg1
    loop:
        use(foo)
        ...
        foo = getVal()
        goto loop;

There we:
* assign foo to the register of arg1.
* use foo, it's dead after this use as it's overwritten after.
* do other things.
* look for a register to put foo in.

If we pick an arbitrary one it might differ from the register the
start of the loop expect's foo to be in.
To fix this we simply look for past register assignments for
the given variable. If we find one and the register is free we
use that register.

This reduces the need for fixup blocks which match the register
assignment between blocks. In the example above between the end
and the head of the loop.

This patch also moves branch weight estimation ahead of register
allocation and adds a flag to control it (cmm-static-pred).
* It means the linear allocator is more likely to assign the hotter
  code paths first.
* If it assign these first we are:
  + Less likely to spill on the hot path.
  + Less likely to introduce fixup blocks on the hot path.

These two measure combined are surprisingly effective. Based on nofib
we get in the mean:

* -0.9% instructions executed
* -0.1% reads/writes
* -0.2% code size.
* -0.1% compiler allocations.
* -0.9% compile time.
* -0.8% runtime.

Most of the benefits are simply a result of removing redundant moves
and spills.

Reduced compiler allocations likely are the result of less code being
generated. (The added lookup is mostly non-allocating).

- - - - -
edc2cc58 by Andreas Klebinger at 2020-05-21T12:14:25-04:00
NCG: Codelayout: Distinguish conditional and other branches.

In #18053 we ended up with a suboptimal code layout because
the code layout algorithm didn't distinguish between conditional
and unconditional control flow.

We can completely eliminate unconditional control flow instructions
by placing blocks next to each other, not so much for conditionals.

In terms of implementation we simply give conditional branches less
weight before computing the layout.

Fixes #18053

- - - - -
b7a6b2f4 by Gleb Popov at 2020-05-21T12:15:26-04:00
gitlab-ci: Set locale to C.UTF-8.

- - - - -
a8c27cf6 by Stefan Holdermans at 2020-05-21T12:16:08-04:00
Allow spaces in GHCi :script file names

This patch updates the user interface of GHCi so that file names passed
to the ':script' command may contain spaces escaped with a backslash.

For example:

  :script foo\ bar.script

The implementation uses a modified version of 'words' that does not
break on escaped spaces.

Fixes #18027.

- - - - -
82663959 by Stefan Holdermans at 2020-05-21T12:16:08-04:00
Add extra tests for GHCi :script syntax checks

The syntax for GHCi's ":script" command allows for only a single file
name to be passed as an argument. This patch adds a test for the cases
in which a file name is missing or multiple file names are passed.

Related to #T18027.

- - - - -
a0b79e1b by Stefan Holdermans at 2020-05-21T12:16:08-04:00
Allow GHCi :script file names in double quotes

This patch updates the user interface of GHCi so that file names passed
to the ':script' command can be wrapped in double quotes.

For example:

  :script "foo bar.script"

The implementation uses a modified version of 'words' that treats
character sequences enclosed in double quotes as single words.

Fixes #18027.

- - - - -
cf566330 by Stefan Holdermans at 2020-05-21T12:16:08-04:00
Update documentation for GHCi :script

This patch adds the fixes that allow for file names containing spaces to
be passed to GHCi's ':script' command to the release notes for 8.12 and
expands the user-guide documentation for ':script' by mentioning how
such file names can be passed.

Related to #18027.

- - - - -
0004ccb8 by Tuan Le at 2020-05-21T12:16:46-04:00
llvmGen: Consider Relocatable read-only data as not constantReferences: #18137

- - - - -
964d3ea2 by John Ericson at 2020-05-21T12:17:30-04:00
Use `Checker` for `tc_pat`

- - - - -
b797aa42 by John Ericson at 2020-05-21T12:17:30-04:00
Use `Checker` for `tc_lpat` and `tc_lpats`

- - - - -
5108e84a by John Ericson at 2020-05-21T12:17:30-04:00
More judiciously panic in `ts_pat`

- - - - -
510e0451 by John Ericson at 2020-05-21T12:17:30-04:00
Put `PatEnv` first in `GHC.Tc.Gen.Pat.Checker`

- - - - -
cb4231db by John Ericson at 2020-05-21T12:17:30-04:00
Tiny cleaup eta-reduce away a function argument

In GHC, not in the code being compiled!

- - - - -
6890c38d by John Ericson at 2020-05-21T12:17:30-04:00
Use braces with do in `SplicePat` case for consistency

- - - - -
3451584f by buggymcbugfix at 2020-05-21T12:18:06-04:00
Fix spelling mistakes and typos

- - - - -
b552e531 by buggymcbugfix at 2020-05-21T12:18:06-04:00
Add INLINABLE pragmas to Enum list producers

The INLINABLE pragmas ensure that we export stable (unoptimised) unfoldings in
the interface file so we can do list fusion at usage sites.

Related tickets: #15185, #8763, #18178.

- - - - -
e7480063 by buggymcbugfix at 2020-05-21T12:18:06-04:00
Piggyback on Enum Word methods for Word64

If we are on a 64 bit platform, we can use the efficient Enum Word
methods for the Enum Word64 instance.

- - - - -
892b0c41 by buggymcbugfix at 2020-05-21T12:18:06-04:00
Document INLINE(ABLE) pragmas that enable fusion

- - - - -
2b363ebb by Richard Eisenberg at 2020-05-21T12:18:45-04:00
MR template should ask for key part
- - - - -
a95bbd0b by Sebastian Graf at 2020-05-21T12:19:37-04:00
Make `Int`'s `mod` and `rem` strict in their first arguments

They used to be strict until 4d2ac2d (9 years ago).

It's obviously better to be strict for performance reasons.
It also blocks #18067.

NoFib results:

```
--------------------------------------------------------------------------------
        Program         Allocs    Instrs
--------------------------------------------------------------------------------
        integer          -1.1%     +0.4%
   wheel-sieve2         +21.2%    +20.7%
--------------------------------------------------------------------------------
            Min          -1.1%     -0.0%
            Max         +21.2%    +20.7%
 Geometric Mean          +0.2%     +0.2%
```

The regression in `wheel-sieve2` is due to reboxing that likely will go
away with the resolution of #18067. See !3282 for details.

Fixes #18187.

- - - - -
d3d055b8 by Galen Huntington at 2020-05-21T12:20:18-04:00
Clarify pitfalls of NegativeLiterals; see #18022.
- - - - -
1b508a9e by Alexey Kuleshevich at 2020-05-21T12:21:02-04:00
Fix wording in primops documentation to reflect the correct reasoning:

* Besides resizing functions, shrinking ones also mutate the
  size of a mutable array and because of those two `sizeofMutabeByteArray`
  and `sizeofSmallMutableArray` are now deprecated
* Change reference in documentation to the newer functions `getSizeof*`
  instead of `sizeof*` for shrinking functions
* Fix incorrect mention of "byte" instead of "small"

- - - - -
4ca0c8a1 by Andreas Klebinger at 2020-05-21T12:21:53-04:00
Don't variable-length encode magic iface constant.

We changed to use variable length encodings for many types by default,
including Word32. This makes sense for numbers but not when Word32 is
meant to represent four bytes.

I added a FixedLengthEncoding newtype to Binary who's instances
interpret their argument as a collection of bytes instead of a number.

We then use this when writing/reading magic numbers to the iface file.

I also took the libery to remove the dummy iface field.

This fixes #18180.

- - - - -
a1275081 by Krzysztof Gogolewski at 2020-05-21T12:22:35-04:00
Add a regression test for #11506

The testcase works now.
See explanation in https://gitlab.haskell.org/ghc/ghc/issues/11506#note_273202

- - - - -
8a816e5f by Krzysztof Gogolewski at 2020-05-21T12:23:55-04:00
Sort deterministically metric output

Previously, we sorted according to the test name and way,
but the metrics (max_bytes_used/peak_megabytes_allocated etc.)
were appearing in nondeterministic order.

- - - - -
566cc73f by Sylvain Henry at 2020-05-21T12:24:45-04:00
Move isDynLinkName into GHC.Types.Name

It doesn't belong into GHC.Unit.State

- - - - -
d830bbc9 by Adam Sandberg Ericsson at 2020-05-23T13:36:20-04:00
docs: fix formatting and add some links

[skip ci]

- - - - -
49301ad6 by Andrew Martin at 2020-05-23T13:37:01-04:00
Implement cstringLength# and FinalPtr

This function and its accompanying rule resolve issue #5218.
A future PR to the bytestring library will make the internal
Data.ByteString.Internal.unsafePackAddress compute string length
with cstringLength#. This will improve the status quo because it is
eligible for constant folding.

Additionally, introduce a new data constructor to ForeignPtrContents
named FinalPtr. This additional data constructor, when used in the
IsString instance for ByteString, leads to more Core-to-Core
optimization opportunities, fewer runtime allocations, and smaller
binaries.

Also, this commit re-exports all the functions from GHC.CString
(including cstringLength#) in GHC.Exts. It also adds a new test
driver. This test driver is used to perform substring matches on Core
that is dumped after all the simplifier passes. In this commit, it is
used to check that constant folding of cstringLength# works.

- - - - -
dcd6bdcc by Ben Gamari at 2020-05-23T13:37:48-04:00
simplCore: Ignore ticks in rule templates

This fixes #17619, where a tick snuck in to the template of a rule,
resulting in a panic during rule matching. The tick in question was
introduced via post-inlining, as discussed in `Note [Simplifying
rules]`. The solution we decided upon was to simply ignore ticks in the
rule template, as discussed in `Note [Tick annotations in RULE
matching]`.

Fixes #18162.
Fixes #17619.

- - - - -
82cb8913 by John Ericson at 2020-05-23T13:38:32-04:00
Fix #18145 and also avoid needless work with implicit vars

 - `forAllOrNothing` now is monadic, so we can trace whether we bind
   an explicit `forall` or not.

 - #18145 arose because the free vars calculation was needlessly
   complex. It is now greatly simplified.

 - Replaced some other implicit var code with `filterFreeVarsToBind`.

Co-authored-by: Ryan Scott <ryan.gl.scott at gmail.com>

- - - - -
a60dc835 by Ben Gamari at 2020-05-23T13:39:12-04:00
Bump process submodule

Fixes #17926.

- - - - -
856adf54 by Ben Gamari at 2020-05-23T13:40:21-04:00
users-guide: Clarify meaning of -haddock flag

Fixes #18206.

- - - - -
7ae57afd by Ben Gamari at 2020-05-23T13:41:03-04:00
git: Add ignored commits file

This can be used to tell git to ignore bulk renaming commits like the
recently-finished module hierarchy refactoring. Configured with,

    git config blame.ignoreRevsFile .git-ignore-revs

- - - - -
63d30e60 by jneira at 2020-05-24T01:54:42-04:00
Add hie-bios script for windows systems
It is a direct translation of the sh script

- - - - -
59182b88 by jneira at 2020-05-24T01:54:42-04:00
Honour previous values for CABAL and CABFLAGS
The immediate goal is let the hie-bios.bat script
set CABFLAGS with `-v0` and remove all cabal output
except the compiler arguments

- - - - -
932dc54e by jneira at 2020-05-24T01:54:42-04:00
Add specific configuration for windows in hie.yaml

- - - - -
e0eda070 by jneira at 2020-05-24T01:54:42-04:00
Remove not needed hie-bios output

- - - - -
a0ea59d6 by Sylvain Henry at 2020-05-24T01:55:24-04:00
Move Config module into GHC.Settings

- - - - -
37430251 by Sylvain Henry at 2020-05-24T01:55:24-04:00
Rename GHC.Core.Arity into GHC.Core.Opt.Arity

- - - - -
a426abb9 by Sylvain Henry at 2020-05-24T01:55:24-04:00
Rename GHC.Hs.Types into GHC.Hs.Type

See discussion in https://gitlab.haskell.org/ghc/ghc/issues/13009#note_268610

- - - - -
1c91a7a0 by Sylvain Henry at 2020-05-24T01:55:24-04:00
Bump haddock submodule

- - - - -
66bd24d1 by Ryan Scott at 2020-05-24T01:56:03-04:00
Add orderingTyCon to wiredInTyCons (#18185)

`Ordering` needs to be wired in for use in the built-in `CmpNat` and
`CmpSymbol` type families, but somehow it was never added to the list
of `wiredInTyCons`, leading to the various oddities observed
in #18185. Easily fixed by moving `orderingTyCon` from
`basicKnownKeyNames` to `wiredInTyCons`.

Fixes #18185.

- - - - -
01c43634 by Matthew Pickering at 2020-05-24T01:56:42-04:00
Remove unused hs-boot file

- - - - -
7a07aa71 by Sylvain Henry at 2020-05-24T15:22:17-04:00
Hadrian: fix cross-compiler build (#16051)

- - - - -
15ccca16 by Sylvain Henry at 2020-05-24T15:22:17-04:00
Hadrian: fix distDir per stage

- - - - -
b420fb24 by Sylvain Henry at 2020-05-24T15:22:17-04:00
Hadrian: fix hp2ps error during cross-compilation

Fixed by @alp (see https://gitlab.haskell.org/ghc/ghc/issues/16051#note_274265)

- - - - -
cd339ef0 by Joshua Price at 2020-05-24T15:22:56-04:00
Make Unicode brackets opening/closing tokens (#18225)

The tokens `[|`, `|]`, `(|`, and `|)` are opening/closing tokens as
described in GHC Proposal #229. This commit makes the unicode
variants (`⟦`, `⟧`, `⦇`, and `⦈`) act the same as their ASCII
counterparts.

- - - - -
013d7120 by Ben Gamari at 2020-05-25T09:48:17-04:00
Revert "Specify kind variables for inferred kinds in base."

As noted in !3132, this has rather severe knock-on consequences in
user-code. We'll need to revisit this before merging something along
these lines.

This reverts commit 9749fe1223d182b1f8e7e4f7378df661c509f396.

- - - - -
4c4312ed by Ben Gamari at 2020-05-25T09:48:53-04:00
Coverage: Drop redundant ad-hoc boot module check

To determine whether the module is a boot module
Coverage.addTicksToBinds was checking for a `boot` suffix in the module
source filename. This is quite ad-hoc and shouldn't be necessary; the
callsite in `deSugar` already checks that the module isn't a boot
module.

- - - - -
1abf3c84 by Ben Gamari at 2020-05-25T09:48:53-04:00
Coverage: Make tickBoxCount strict

This could otherwise easily cause a leak of (+) thunks.

- - - - -
b2813750 by Ben Gamari at 2020-05-25T09:48:53-04:00
Coverage: Make ccIndices strict

This just seems like a good idea.

- - - - -
02e278eb by Ben Gamari at 2020-05-25T09:48:53-04:00
Coverage: Don't produce ModBreaks if not HscInterpreted

emptyModBreaks contains a bottom and consequently it's important that we
don't use it unless necessary.

- - - - -
b8c014ce by Ben Gamari at 2020-05-25T09:48:53-04:00
Coverage: Factor out addMixEntry

- - - - -
53814a64 by Zubin Duggal at 2020-05-26T03:03:24-04:00
Add info about typeclass evidence to .hie files

See `testsuite/tests/hiefile/should_run/HieQueries.hs` and
`testsuite/tests/hiefile/should_run/HieQueries.stdout` for an example of this

We add two new fields, `EvidenceVarBind` and `EvidenceVarUse` to the
`ContextInfo` associated with an Identifier. These are associated with the
appropriate identifiers for the evidence variables collected when we come across
`HsWrappers`, `TcEvBinds` and `IPBinds` while traversing the AST.

Instance dictionary and superclass selector dictionaries from `tcg_insts` and
classes defined in `tcg_tcs` are also recorded in the AST as originating from
their definition span

This allows us to save a complete picture of the evidence constructed by the
constraint solver, and will let us report this to the user, enabling features
like going to the instance definition from the invocation of a class method(or
any other method taking a constraint) and finding all usages of a particular
instance.

Additionally,

- Mark NodeInfo with an origin so we can differentiate between bindings
  origininating in the source vs those in ghc
- Along with typeclass evidence info, also include information on Implicit
  Parameters
- Add a few utility functions to HieUtils in order to query the new info

Updates haddock submodule

- - - - -
6604906c by Sebastian Graf at 2020-05-26T03:04:04-04:00
Make WorkWrap.Lib.isWorkerSmallEnough aware of the old arity

We should allow a wrapper with up to 82 parameters when the original
function had 82 parameters to begin with.

I verified that this made no difference on NoFib, but then again
it doesn't use huge records...

Fixes #18122.

- - - - -
cf772f19 by Sylvain Henry at 2020-05-26T03:04:45-04:00
Enhance Note [About units] for Backpack

- - - - -
ede24126 by Takenobu Tani at 2020-05-27T00:13:55-04:00
core-spec: Modify file paths according to new module hierarchy

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

  * GHC/Core.hs                <= coreSyn/CoreSyn.hs
  * GHC/Core/Coercion.hs       <= types/Coercion.hs
  * GHC/Core/Coercion/Axiom.hs <= types/CoAxiom.hs
  * GHC/Core/Coercion/Opt.hs   <= types/OptCoercion.hs
  * GHC/Core/DataCon.hs        <= basicTypes/DataCon.hs
  * GHC/Core/FamInstEnv.hs     <= types/FamInstEnv.hs
  * GHC/Core/Lint.hs           <= coreSyn/CoreLint.hs
  * GHC/Core/Subst.hs          <= coreSyn/CoreSubst.hs
  * GHC/Core/TyCo/Rep.hs       <= types/TyCoRep.hs
  * GHC/Core/TyCon.hs          <= types/TyCon.hs
  * GHC/Core/Type.hs           <= types/Type.hs
  * GHC/Core/Unify.hs          <= types/Unify.hs
  * GHC/Types/Literal.hs       <= basicTypes/Literal.hs
  * GHC/Types/Var.hs           <= basicTypes/Var.hs

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

[skip ci]

- - - - -
04750304 by Ben Gamari at 2020-05-27T00:14:33-04:00
eventlog: Fix racy flushing

Previously no attempt was made to avoid multiple threads writing their
capability-local eventlog buffers to the eventlog writer simultaneously.
This could result in multiple eventlog streams being interleaved. Fix
this by documenting that the EventLogWriter's write() and flush()
functions may be called reentrantly and fix the default writer to
protect its FILE* by a mutex.

Fixes #18210.

- - - - -
d6203f24 by Joshua Price at 2020-05-27T00:15:17-04:00
Make `identifier` parse unparenthesized `->` (#18060)

- - - - -
28deee28 by Ben Gamari at 2020-05-28T16:23:21-04:00
GHC.Core.Unfold: Refactor traceInline

This reduces duplication as well as fixes a bug wherein -dinlining-check
would override -ddump-inlinings. Moreover, the new variant

- - - - -
1f393e1e by Ben Gamari at 2020-05-28T16:23:21-04:00
Avoid unnecessary allocations due to tracing utilities

While ticky-profiling the typechecker I noticed that hundreds of
millions of SDocs are being allocated just in case -ddump-*-trace is
enabled. This is awful.

We avoid this by ensuring that the dump flag check is inlined into the
call site, ensuring that the tracing document needn't be allocated
unless it's actually needed.

See Note [INLINE conditional tracing utilities] for details.

Fixes #18168.

Metric Decrease:
  T9961
  haddock.Cabal
  haddock.base
  haddock.compiler

- - - - -
5f621a78 by Vladislav Zavialov at 2020-05-28T16:23:58-04:00
Add Semigroup/Monoid for Q (#18123)

- - - - -
dc5f004c by Xavier Denis at 2020-05-28T16:24:37-04:00
Fix #18071

Run the core linter on candidate instances to ensure they are
well-kinded.

Better handle quantified constraints by using a CtWanted to avoid
having unsolved constraints thrown away at the end by the solver.

- - - - -
10e6982c by Sebastian Graf at 2020-05-28T16:25:14-04:00
FloatOut: Only eta-expand dead-end RHS if arity will increase (#18231)

Otherwise we risk turning trivial RHS into non-trivial RHS, introducing
unnecessary bindings in the next Simplifier run, resulting in more
churn.

Fixes #18231.

- - - - -
08dab5f7 by Sebastian Graf at 2020-05-28T16:25:14-04:00
DmdAnal: Recognise precise exceptions from case alternatives (#18086)

Consider

```hs
m :: IO ()
m = do
  putStrLn "foo"
  error "bar"
```

`m` (from #18086) always throws a (precise or imprecise) exception or
diverges. Yet demand analysis infers `<L,A>` as demand signature instead
of `<L,A>x` for it.

That's because the demand analyser sees `putStrLn` occuring in a case
scrutinee and decides that it has to `deferAfterPreciseException`,
because `putStrLn` throws a precise exception on some control flow
paths. This will mask the `botDiv` `Divergence`of the single case alt
containing `error` to `topDiv`. Since `putStrLn` has `topDiv` itself,
the final `Divergence` is `topDiv`.

This is easily fixed: `deferAfterPreciseException` works by `lub`ing
with the demand type of a virtual case branch denoting the precise
exceptional control flow. We used `nopDmdType` before, but we can be
more precise and use `exnDmdType`, which is `nopDmdType` with `exnDiv`.

Now the `Divergence` from the case alt will degrade `botDiv` to `exnDiv`
instead of `topDiv`, which combines with the result from the scrutinee
to `exnDiv`, and all is well.

Fixes #18086.

- - - - -
aef95f11 by Ben Gamari at 2020-05-28T16:25:53-04:00
Ticky-ticky: Record DataCon name in ticker name

This makes it significantly easier to spot the nature of
allocations regressions and comes at a reasonably low cost.

- - - - -
8f021b8c by Ben Gamari at 2020-05-28T16:26:34-04:00
hadrian: Don't track GHC's verbosity argument

Teach hadrian to ignore GHC's -v argument in its recompilation check,
thus fixing #18131.

- - - - -
13d9380b by Ben Gamari at 2020-05-28T16:27:20-04:00
Rip out CmmStackInfo(updfr_space)

As noted in #18232, this field is currently completely unused and
moreover doesn't have a clear meaning.

- - - - -
f10d11fa by Andreas Klebinger at 2020-05-29T01:38:42-04:00
Fix "build/elem" RULE.

An redundant constraint prevented the rule from matching.

Fixing this allows a call to elem on a known list to be translated
into a series of equality checks, and eventually a simple case
expression.

Surprisingly this seems to regress elem for strings. To avoid
this we now also allow foldrCString to inline and add an UTF8
variant. This results in elem being compiled to a tight
non-allocating loop over the primitive string literal which
performs a linear search.

In the process this commit adds UTF8 variants for some of the
functions in GHC.CString. This is required to make this work for
both ASCII and UTF8 strings.

There are also small tweaks to the CString related rules.
We now allow ourselfes the luxury to compare the folding function
via eqExpr, which helps to ensure the rule fires before we inline
foldrCString*. Together with a few changes to allow matching on both
the UTF8 and ASCII variants of the CString functions.

- - - - -
bbeb2389 by Ben Gamari at 2020-05-29T01:39:19-04:00
CoreToStg: Add Outputable ArgInfo instance

- - - - -
0e3361ca by Simon Peyton Jones at 2020-05-29T01:39:19-04:00
Make Lint check return type of a join point

Consider
   join x = rhs in body
It's important that the type of 'rhs' is the same as the type of
'body', but Lint wasn't checking that invariant.

Now it does!  This was exposed by investigation into !3113.

- - - - -
c49f7df0 by Simon Peyton Jones at 2020-05-29T01:39:19-04:00
Do not float join points in exprIsConApp_maybe

We hvae been making exprIsConApp_maybe cleverer in recent times:

    commit b78cc64e923716ac0512c299f42d4d0012306c05
    Date:   Thu Nov 15 17:14:31 2018 +0100
    Make constructor wrappers inline only during the final phase

    commit 7833cf407d1f608bebb1d38bb99d3035d8d735e6
    Date:   Thu Jan 24 17:58:50 2019 +0100
    Look through newtype wrappers (Trac #16254)

    commit c25b135ff5b9c69a90df0ccf51b04952c2dc6ee1
    Date:   Thu Feb 21 12:03:22 2019 +0000
    Fix exprIsConApp_maybe

But alas there was still a bug, now immortalised in
  Note [Don't float join points]
in SimpleOpt.

It's quite hard to trigger because it requires a dead
join point, but it came up when compiling Cabal
Cabal.Distribution.Fields.Lexer.hs, when working on
!3113.

Happily, the fix is extremly easy.  Finding the
bug was not so easy.

- - - - -
46720997 by Ben Gamari at 2020-05-29T01:39:19-04:00
Allow simplification through runRW#

Because runRW# inlines so late, we were previously able to do very
little simplification across it. For instance, given even a simple
program like

    case runRW# (\s -> let n = I# 42# in n) of
      I# n# -> f n#

we previously had no way to avoid the allocation of the I#.

This patch allows the simplifier to push strict contexts into the
continuation of a runRW# application, as explained in
in Note [Simplification of runRW#] in GHC.CoreToStg.Prep.

Fixes #15127.

Metric Increase:
    T9961
Metric Decrease:
    ManyConstructors

Co-Authored-By: Simon Peyton-Jone <simonpj at microsoft.com>

- - - - -
277c2f26 by Ben Gamari at 2020-05-29T01:39:55-04:00
Eta expand un-saturated primops

Now since we no longer try to predict CAFfyness we have no need for the
solution to #16846. Eta expanding unsaturated primop applications is
conceptually simpler, especially in the presence of levity polymorphism.

This essentially reverts cac8dc9f51e31e4c0a6cd9bc302f7e1bc7c03beb,
as suggested in #18079.

Closes #18079.

- - - - -
f44d7ae0 by Simon Jakobi at 2020-05-29T01:40:34-04:00
base: Scrap deprecation plan for Data.Monoid.{First,Last}

See the discussion on the libraries mailing list for context:

https://mail.haskell.org/pipermail/libraries/2020-April/030357.html

- - - - -
8b494895 by Jeremy Schlatter at 2020-05-29T01:41:12-04:00
Fix typo in documentation

- - - - -
998450f4 by Gleb Popov at 2020-05-29T01:41:53-04:00
Always define USE_PTHREAD_FOR_ITIMER for FreeBSD.

- - - - -
f9a513e0 by Alp Mestanogullari at 2020-05-29T01:42:36-04:00
hadrian: introduce 'install' target

Its logic is very simple. It `need`s the `binary-dist-dir` target
and runs suitable `configure` and `make install` commands for the
user. A new `--prefix` command line argument is introduced to
specify where GHC should be installed.

- - - - -
67738db1 by Travis Whitaker at 2020-05-29T13:34:48-04:00
Build a threaded stage 1 if the bootstrapping GHC supports it.

- - - - -
aac19e6c by Peter Trommler at 2020-05-29T13:35:24-04:00
PPC NCG: No per-symbol .section ".toc" directives

All position independent symbols are collected during code generation
and emitted in one go. Prepending each symbol with a .section ".toc"
directive is redundant. This patch drops the per-symbol directives
leading to smaller assembler files.

Fixes #18250

- - - - -
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

- - - - -
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.

- - - - -
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

- - - - -
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
-------------------------

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

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

- - - - -
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().

- - - - -
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.

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

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

- - - - -
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.

- - - - -
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.

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

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

Mirrors the behaviour of `lintType`.

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

- - - - -
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.

- - - - -
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

- - - - -
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.

- - - - -
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.

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

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

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

- - - - -
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

- - - - -
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

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

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

- - - - -
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

- - - - -
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.

- - - - -
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.

- - - - -
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.

- - - - -
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.

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

Due to #18298.

- - - - -
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.

- - - - -
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

- - - - -
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.

- - - - -
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

- - - - -
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.

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

- - - - -
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.

- - - - -
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.

- - - - -
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

- - - - -
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).

- - - - -
6c888db3 by Simon Peyton Jones at 2020-07-23T12:57:10+01:00
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.

- - - - -


16 changed files:

- + .git-ignore-revs
- .gitlab-ci.yml
- .gitlab/ci.sh
- .gitlab/linters/check-cpp.py
- .gitlab/merge_request_templates/merge-request.md
- .gitlab/test-metrics.sh
- .gitmodules
- CODEOWNERS
- Makefile
- aclocal.m4
- compiler/GHC.hs
- + compiler/GHC/Builtin/Names.hs
- + compiler/GHC/Builtin/Names/TH.hs
- + compiler/GHC/Builtin/PrimOps.hs
- + compiler/GHC/Builtin/PrimOps.hs-boot
- + 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/e245779ff0d183c6b1040ef25583f7083617f0a6...6c888db3275310c2cf875fb82e354ab567d2f84c

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e245779ff0d183c6b1040ef25583f7083617f0a6...6c888db3275310c2cf875fb82e354ab567d2f84c
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