[Git][ghc/ghc][wip/proposal-195] 199 commits: gitlab-ci: Allow ARMv7 job to fail

Sylvain Henry gitlab at gitlab.haskell.org
Thu Jul 9 13:26:16 UTC 2020



Sylvain Henry pushed to branch wip/proposal-195 at Glasgow Haskell Compiler / GHC


Commits:
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.

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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

- - - - -
652b3e85 by Matthew Pickering at 2020-07-09T15:23:25+02:00
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.

- - - - -


30 changed files:

- .gitlab-ci.yml
- .gitlab/ci.sh
- .gitlab/test-metrics.sh
- .gitmodules
- aclocal.m4
- compiler/GHC.hs
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/Names/TH.hs
- compiler/GHC/Builtin/PrimOps.hs
- compiler/GHC/Builtin/Types.hs
- compiler/GHC/Builtin/Types.hs-boot
- compiler/GHC/Builtin/Types/Prim.hs
- compiler/GHC/Builtin/Utils.hs
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/ByteCode/Asm.hs
- compiler/GHC/ByteCode/InfoTable.hs
- compiler/GHC/ByteCode/Linker.hs
- compiler/GHC/ByteCode/Types.hs
- compiler/GHC/Cmm/CLabel.hs
- compiler/GHC/Cmm/CallConv.hs
- compiler/GHC/Cmm/Dataflow/Block.hs
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/Info.hs
- compiler/GHC/Cmm/Info/Build.hs
- compiler/GHC/Cmm/LayoutStack.hs
- compiler/GHC/Cmm/MachOp.hs
- compiler/GHC/Cmm/Monad.hs
- compiler/GHC/Cmm/Node.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/Cmm/Pipeline.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/48c844a2d7a8066ecb4e45ad4dca2ae042e02b66...652b3e85ee41fd9d42c5162f258ec8eedc29c651

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/48c844a2d7a8066ecb4e45ad4dca2ae042e02b66...652b3e85ee41fd9d42c5162f258ec8eedc29c651
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