[Git][ghc/ghc][wip/toolchain-selection] 10 commits: base: add COMPLETE pragma to BufferCodec PatSyn

Tue Jul 18 01:18:23 UTC 2023

Rodrigo Mesquita pushed to branch wip/toolchain-selection at Glasgow Haskell Compiler / GHC

Commits:
22565506 by sheaf at 2023-07-17T21:12:59-04:00
base: add COMPLETE pragma to BufferCodec PatSyn

This implements CLC proposal #178, rectifying an oversight in the
implementation of CLC proposal #134 which could lead to spurious
pattern match warnings.

https://github.com/haskell/core-libraries-committee/issues/178
https://github.com/haskell/core-libraries-committee/issues/134

- - - - -
860f6269 by sheaf at 2023-07-17T21:13:00-04:00
exactprint: silence incomplete record update warnings

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df706de3 by sheaf at 2023-07-17T21:13:00-04:00
Re-instate -Wincomplete-record-updates

Commit e74fc066 refactored the handling of record updates to use
the HsExpanded mechanism. This meant that the pattern matching inherent
to a record update was considered to be "generated code", and thus we
stopped emitting "incomplete record update" warnings entirely.

This commit changes the "data Origin = Source | Generated" datatype,
adding a field to the Generated constructor to indicate whether we
still want to perform pattern-match checking. We also have to do a bit
of plumbing with HsCase, to record that the HsCase arose from an
HsExpansion of a RecUpd, so that the error message continues to mention
record updates as opposed to a generic "incomplete pattern matches in case"
error.

Finally, this patch also changes the way we handle inaccessible code
warnings. Commit e74fc066 was also a regression in this regard, as we
were emitting "inaccessible code" warnings for case statements spuriously
generated when desugaring a record update (remember: the desugaring mechanism
happens before typechecking; it thus can't take into account e.g. GADT information
in order to decide which constructors to include in the RHS of the desugaring
of the record update).
We fix this by changing the mechanism through which we disable inaccessible
code warnings: we now check whether we are in generated code in
GHC.Tc.Utils.TcMType.newImplication in order to determine whether to
emit inaccessible code warnings.

Fixes #23520
Updates haddock submodule, to avoid incomplete record update warnings

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1d05971e by sheaf at 2023-07-17T21:13:00-04:00
Propagate long-distance information in do-notation

The preceding commit re-enabled pattern-match checking inside record
updates. This revealed that #21360 was in fact NOT fixed by e74fc066.

This commit makes sure we correctly propagate long-distance information
in do blocks, e.g. in

```haskell
data T = A { fld :: Int } | B

f :: T -> Maybe T
f r = do
  a at A{} <- Just r
  Just $ case a of { A _ -> A 9 }
```

we need to propagate the fact that "a" is headed by the constructor "A"
to see that the case expression "case a of { A _ -> A 9 }" cannot fail.

Fixes #21360

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bea0e323 by sheaf at 2023-07-17T21:13:00-04:00
Skip PMC for boring patterns

Some patterns introduce no new information to the pattern-match
checker (such as plain variable or wildcard patterns). We can thus
skip doing any pattern-match checking on them when the sole purpose
for doing so was introducing new long-distance information.

See Note [Boring patterns] in GHC.Hs.Pat.

Doing this avoids regressing in performance now that we do additional
pattern-match checking inside do notation.

- - - - -
ddcdd88c by Rodrigo Mesquita at 2023-07-17T21:13:36-04:00
Split GHC.Platform.ArchOS from ghc-boot into ghc-platform

Split off the `GHC.Platform.ArchOS` module from the `ghc-boot` package
into this reinstallable standalone package which abides by the PVP, in
part motivated by the ongoing work on `ghc-toolchain` towards runtime
retargetability.

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b55a8ea7 by Sylvain Henry at 2023-07-17T21:14:27-04:00
JS: better implementation for plusWord64 (#23597)

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c748d65b by Ben Gamari at 2023-07-18T02:14:56+01:00
ghc-toolchain: Initial commit

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1c139b5d by Rodrigo Mesquita at 2023-07-18T02:14:56+01:00
ghc-toolchain: Toolchain Selection

This commit integrates ghc-toolchain, the brand new way of configuring
toolchains for GHC, with the Hadrian build system, with configure, and
extends and improves the first iteration of ghc-toolchain.

The general overview is

* We introduce a program invoked `ghc-toolchain --triple=...` which, when run,
  produces a file with a `Target`. A `GHC.Toolchain.Target.Target`
  describes the properties of a target and the toolchain (executables
  and configured flags) to produce code for that target

* Hadrian was modified to read Target files, and will both
  * Invoke the toolchain configured in the Target file as needed
  * Produce a `settings` file for GHC based on the Target file for that stage

* `./configure` will invoke ghc-toolchain to generate target files, but
  it will also generate target files based on the flags configure itself
  configured (through `.in` files that are substituted)

  * By default, the Targets generated by configure are still (for now) the ones used by Hadrian

  * But we additionally validate the Target files generated by
    ghc-toolchain against the ones generated by configure, to get a head
    start on catching configuration bugs before we transition
    completely.

  * When we make that transition, we will want to drop a lot of the
    toolchain configuration logic from configure, but keep it otherwise.

* For each compiler stage we should have 1 target file (up to a stage compiler we can't run in our machine)
  * We just have a HOST target file, which we use as the target for stage0
  * And a TARGET target file, which we use for stage1 (and later stages, if not cross compiling)
  * Note there is no BUILD target file, because we only support cross compilation where BUILD=HOST
  * (for more details on cross-compilation see discussion on !9263)

See also
* Note [How we configure the bundled windows toolchain]
* Note [ghc-toolchain consistency checking]
* Note [ghc-toolchain overview]

Ticket: #19877
MR: !9263

- - - - -
4b8c0553 by Rodrigo Mesquita at 2023-07-18T02:14:56+01:00
Add flag to enable/disable ghc-toolchain based configurations

This flag is disabled by default, and we'll use the
configure-generated-toolchains by default until we remove the toolchain
configuration logic from configure.

- - - - -

30 changed files:

- compiler/GHC/Hs/Expr.hs
- compiler/GHC/Hs/Pat.hs
- compiler/GHC/Hs/Utils.hs
- compiler/GHC/HsToCore/Arrows.hs
- compiler/GHC/HsToCore/Errors/Ppr.hs
- compiler/GHC/HsToCore/Errors/Types.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/GuardedRHSs.hs
- compiler/GHC/HsToCore/ListComp.hs
- compiler/GHC/HsToCore/Match.hs
- compiler/GHC/HsToCore/Match.hs-boot
- compiler/GHC/HsToCore/Match/Constructor.hs
- compiler/GHC/HsToCore/Monad.hs
- compiler/GHC/HsToCore/Pmc.hs
- compiler/GHC/HsToCore/Pmc/Utils.hs
- compiler/GHC/HsToCore/Utils.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/Linker/Static.hs
- compiler/GHC/Platform.hs
- compiler/GHC/Rename/Expr.hs
- compiler/GHC/Rename/Utils.hs
- compiler/GHC/Tc/Deriv/Generate.hs
- compiler/GHC/Tc/Gen/Expr.hs
- compiler/GHC/Tc/Gen/Splice.hs
- compiler/GHC/Tc/TyCl/Instance.hs
- compiler/GHC/Tc/TyCl/PatSyn.hs
- compiler/GHC/Tc/TyCl/Utils.hs
- compiler/GHC/Tc/Types/Constraint.hs
- compiler/GHC/Tc/Utils/Monad.hs
- compiler/GHC/Tc/Utils/TcMType.hs

The diff was not included because it is too large.

View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/aebfe1bf41d809b2cbc5d16d7a5053c818c6af41...4b8c05537c789f50182799ee18394c3ba974a621

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/aebfe1bf41d809b2cbc5d16d7a5053c818c6af41...4b8c05537c789f50182799ee18394c3ba974a621
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