[Git][ghc/ghc][wip/romes/ttg-zurich] 25 commits: Clarify -XGADTs enables existential quantification

Rodrigo Mesquita (@alt-romes) gitlab at gitlab.haskell.org
Fri Jun 21 14:05:37 UTC 2024 


Rodrigo Mesquita pushed to branch wip/romes/ttg-zurich at Glasgow Haskell Compiler / GHC


Commits:
d70abb49 by sheaf at 2024-06-18T18:47:20-04:00
Clarify -XGADTs enables existential quantification

Even though -XGADTs does not turn on -XExistentialQuantification,
it does allow the user of existential quantification syntax, without
needing to use GADT-style syntax.

Fixes #20865

- - - - -
13fdf788 by David Binder at 2024-06-18T18:48:02-04:00
Add RTS flag --read-tix-file (GHC Proposal 612)

This commit introduces the RTS flag `--read-tix-file=<yes|no>` which
controls whether a preexisting .tix file is read in at the beginning
of a program run. The default is currently `--read-tix-file=yes` but
will change to `--read-tix-file=no` in a future release of GHC. For
this reason, whenever a .tix file is read in a warning is emitted to
stderr. This warning can be silenced by explicitly passing the
`--read-tix-file=yes` option. Details can be found in the GHC proposal
cited below.

Users can query whether this flag has been used with the help of the
module `GHC.RTS.Flags`. A new field `readTixFile` was added to the
record `HpcFlags`.

These changes have been discussed and approved in
- GHC proposal 612: https://github.com/ghc-proposals/ghc-proposals/pull/612
- CLC proposal 276: https://github.com/haskell/core-libraries-committee/issues/276

- - - - -
f0e3cb6a by Fendor at 2024-06-18T18:48:38-04:00
Improve sharing of duplicated values in `ModIface`, fixes #24723

As a `ModIface` often contains duplicated values that are not
necessarily shared, we improve sharing by serialising the `ModIface`
to an in-memory byte array. Serialisation uses deduplication tables, and
deserialisation implicitly shares duplicated values.

This helps reducing the peak memory usage while compiling in
`--make` mode. The peak memory usage is especially smaller when
generating interface files with core expressions
(`-fwrite-if-simplified-core`).

On agda, this reduces the peak memory usage:

* `2.2 GB` to `1.9 GB` for a ghci session.

On `lib:Cabal`, we report:

* `570 MB` to `500 MB` for a ghci session
* `790 MB` to `667 MB` for compiling `lib:Cabal` with ghc

There is a small impact on execution time, around 2% on the agda code
base.

- - - - -
1bab7dde by Fendor at 2024-06-18T18:48:38-04:00
Avoid unneccessarily re-serialising the `ModIface`

To reduce memory usage of `ModIface`, we serialise `ModIface` to an
in-memory byte array, which implicitly shares duplicated values.

This serialised byte array can be reused to avoid work when we actually
write the `ModIface` to disk.
We introduce a new field to `ModIface` which allows us to save the byte
array, and write it direclty to disk if the `ModIface` wasn't changed
after the initial serialisation.

This requires us to change absolute offsets, for example to jump to the
deduplication table for `Name` or `FastString` with relative offsets, as
the deduplication byte array doesn't contain header information, such as
fingerprints.
To allow us to dump the binary blob to disk, we need to replace all
absolute offsets with relative ones.

We introduce additional helpers for `ModIface` binary serialisation, which
construct relocatable binary blobs. We say the binary blob is relocatable,
if the binary representation can be moved and does not contain any
absolute offsets.

Further, we introduce new primitives for `Binary` that allow to create
relocatable binaries, such as `forwardGetRel` and `forwardPutRel`.

-------------------------
Metric Decrease:
    MultiLayerModulesDefsGhcWithCore
Metric Increase:
    MultiComponentModules
    MultiLayerModules
    T10421
    T12150
    T12234
    T12425
    T13035
    T13253-spj
    T13701
    T13719
    T14697
    T15703
    T16875
    T18698b
    T18140
    T18304
    T18698a
    T18730
    T18923
    T20049
    T24582
    T5837
    T6048
    T9198
    T9961
    mhu-perf
-------------------------

These metric increases may look bad, but they are all completely benign,
we simply allocate 1 MB per module for `shareIface`. As this allocation
is quite quick, it has a negligible impact on run-time performance.
In fact, the performance difference wasn't measurable on my local
machine. Reducing the size of the pre-allocated 1 MB buffer avoids these
test failures, but also requires us to reallocate the buffer if the
interface file is too big. These reallocations *did* have an impact on
performance, which is why I have opted to accept all these metric
increases, as the number of allocated bytes is merely a guidance.

This 1MB allocation increase causes a lot of tests to fail that
generally have a low allocation number. E.g., increasing from 40MB to
41MB is a 2.5% increase.
In particular, the tests T12150, T13253-spj, T18140, T18304, T18698a,
T18923, T20049, T24582, T5837, T6048, and T9961 only fail on i386-darwin
job, where the number of allocated bytes seems to be lower than in other
jobs.
The tests T16875 and T18698b fail on i386-linux for the same reason.

- - - - -
099992df by Andreas Klebinger at 2024-06-18T18:49:14-04:00
Improve documentation of @Any@ type.

In particular mention possible uses for non-lifted types.

Fixes #23100.

- - - - -
5e75412b by Jakob Bruenker at 2024-06-18T18:49:51-04:00
Update user guide to indicate support for 64-tuples

- - - - -
4f5da595 by Andreas Klebinger at 2024-06-18T18:50:28-04:00
lint notes: Add more info to notes.stdout

When fixing a note reference CI fails with a somewhat confusing diff.
See #21123. This commit adds a line to the output file being compared
which hopefully makes it clear this is the list of broken refs, not all
refs.

Fixes #21123

- - - - -
1eb15c61 by Jakob Bruenker at 2024-06-18T18:51:04-04:00
docs: Update mention of ($) type in user guide

Fixes #24909

- - - - -
1d66c9e3 by Jan Hrček at 2024-06-18T18:51:47-04:00
Remove duplicate Anno instances

- - - - -
8ea0ba95 by Sven Tennie at 2024-06-18T18:52:23-04:00
AArch64: Delete unused RegNos

This has the additional benefit of getting rid of the -1 encoding (real
registers start at 0.)

- - - - -
325422e0 by Sjoerd Visscher at 2024-06-18T18:53:04-04:00
Bump stm submodule to current master

- - - - -
64fba310 by Cheng Shao at 2024-06-18T18:53:40-04:00
testsuite: bump T17572 timeout on wasm32

- - - - -
eb612fbc by Sven Tennie at 2024-06-19T06:46:00-04:00
AArch64: Simplify BL instruction

The BL constructor carried unused data in its third argument.

- - - - -
b0300503 by Alan Zimmerman at 2024-06-19T06:46:36-04:00
TTG: Move SourceText from `Fixity` to `FixitySig`

It is only used there, simplifies the use of `Fixity` in the rest of
the code, and is moved into a TTG extension point.

Precedes !12842, to simplify it

- - - - -
842e119b by Rodrigo Mesquita at 2024-06-19T06:47:13-04:00
base: Deprecate some .Internal modules

Deprecates the following modules according to clc-proposal #217:
https://github.com/haskell/core-libraries-committee/issues/217

* GHC.TypeNats.Internal
* GHC.TypeLits.Internal
* GHC.ExecutionStack.Internal

Closes #24998

- - - - -
e965aae6 by Adriaan Leijnse at 2024-06-21T15:05:27+01:00
ttg: Remove SourceText from OverloadedLabel

Progress towards #21592

- - - - -
1b01990c by Alexander Foremny at 2024-06-21T15:05:27+01:00
AST: GHC.Prelude -> Prelude

Refactor occurrences to GHC.Prelude with Prelude within
Language/Haskell.

Progress towards #21592

- - - - -
75583e0e by Alexander Foremny at 2024-06-21T15:05:27+01:00
AST: remove occurrences of GHC.Unit.Module.ModuleName

`GHC.Unit.Module` re-exports `ModuleName` from
`Language.Haskell.Syntax.Module.Name`.

Progress towards #21592

- - - - -
10e85e12 by Fabian Kirchner at 2024-06-21T15:05:27+01:00
AST: move Data instance definition for ModuleName to GHC.Unit.Types

To remove the dependency on GHC.Utils.Misc inside
Language.Haskell.Syntax.Module.Name, the instance definition is moved
from there into GHC.Unit.Types.

Progress towards #21592

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b8a5c13c by Fabian Kirchner at 2024-06-21T15:05:27+01:00
AST: move negateOverLitVal into GHC.Hs.Lit

The function negateOverLitVal is not used within Language.Haskell and
therefore can be moved to the respective module inside GHC.Hs.

Progress towards #21592

- - - - -
45129ebb by Fabian Kirchner at 2024-06-21T15:05:27+01:00
AST: move conDetailsArity into GHC.Rename.Module

The function conDetailsArity is only used inside GHC.Rename.Module.  We
therefore move it there from Language.Haskell.Syntax.Lit.

Progress towards #21592

- - - - -
891ad15f by Mauricio at 2024-06-21T15:05:27+01:00
AST: Remove GHC.Utils.Assert from GHC

Simple cleanup.

Progress towards #21592

- - - - -
a8e55a33 by Fabian Kirchner at 2024-06-21T15:05:27+01:00
ttg: extract Specificity, ForAllTyFlag and helper functions from GHC.Types.Var

Progress towards #21592

Specificity, ForAllTyFlag and its' helper functions are extracted from
GHC.Types.Var and moved into a new module Language.Haskell.Syntax.Specificity.

Note: Eventually (i.e. after Language.Haskell.Syntax.Decls does not depend on
GHC.* anymore) these should be moved into Language.Haskell.Syntax.Decls.
At this point, this would cause cyclic dependencies.

- - - - -
3246e0e5 by Adowrath at 2024-06-21T15:05:27+01:00
ttg: Split HsSrcBang, remove ref to DataCon from Syntax.Type

Progress towards #21592

This splits HsSrcBang up, creating the new HsBang within
`Language.Haskell.Syntax.Basic`. `HsBang` holds the unpackedness
and strictness information, while `HsSrcBang` only adds the SourceText
for usage within the compiler directly.

Inside the AST, to preserve the SourceText, it is hidden behind the
pre-existing extension point `XBindTy`. All other occurrences of
`HsSrcBang` were adapted to deconstruct the inner `HsBang`, and when
interacting with the `BindTy` constructor, the hidden `SourceText` is
extracted/inserted into the `XBindTy` extension point.

`GHC.Core.DataCon` exports both `HsSrcBang` and `HsBang` for
convenience. A constructor function `mkHsSrcBang` that takes all
individual components has been added.

Two exceptions has been made though:
- The `Outputable HsSrcBang` instance is replaced by
  `Outputable HsBang`. While being only GHC-internal, the only place
  it's used is in outputting `HsBangTy` constructors -- which already
  have `HsBang`. It wouldn't make sense to reconstruct a `HsSrcBang` just
  to ignore the `SourceText` anyway.
- The error `TcRnUnexpectedAnnotation` did not use the `SourceText`,
  so it too now only holds a `HsBang`.

- - - - -
93af4f54 by Mauricio at 2024-06-21T15:05:28+01:00
AST: Moved definitions that use GHC.Utils.Panic to GHC namespace

Progress towards #21592

- - - - -


30 changed files:

- compiler/GHC.hs
- compiler/GHC/Builtin/PrimOps.hs
- compiler/GHC/Builtin/Types.hs
- compiler/GHC/CmmToAsm/AArch64/CodeGen.hs
- compiler/GHC/CmmToAsm/AArch64/Instr.hs
- compiler/GHC/CmmToAsm/AArch64/Ppr.hs
- compiler/GHC/Core/DataCon.hs
- compiler/GHC/Core/TyCo/Rep.hs-boot
- compiler/GHC/CoreToIface.hs
- compiler/GHC/Hs.hs
- compiler/GHC/Hs/Binds.hs
- compiler/GHC/Hs/Decls.hs
- compiler/GHC/Hs/Dump.hs
- compiler/GHC/Hs/Expr.hs
- compiler/GHC/Hs/Lit.hs
- + compiler/GHC/Hs/Specificity.hs
- compiler/GHC/Hs/Syn/Type.hs
- compiler/GHC/Hs/Type.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/Iface/Binary.hs
- compiler/GHC/Iface/Ext/Binary.hs
- compiler/GHC/Iface/Ext/Fields.hs
- compiler/GHC/Iface/Load.hs
- compiler/GHC/Iface/Make.hs
- compiler/GHC/Iface/Recomp.hs
- compiler/GHC/Iface/Rename.hs
- compiler/GHC/IfaceToCore.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/Annotation.hs


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