[Git][ghc/ghc][wip/wither-eq1-and-friends] 40 commits: Improve BUILD_PAP comments

Matthew Pickering (@mpickering) gitlab at gitlab.haskell.org
Wed Aug 10 08:25:11 UTC 2022



Matthew Pickering pushed to branch wip/wither-eq1-and-friends at Glasgow Haskell Compiler / GHC


Commits:
e9c77a22 by Andreas Klebinger at 2022-08-06T06:13:17-04:00
Improve BUILD_PAP comments

- - - - -
41234147 by Andreas Klebinger at 2022-08-06T06:13:17-04:00
Make dropTail comment a haddock comment

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ff11d579 by Andreas Klebinger at 2022-08-06T06:13:17-04:00
Add one more sanity check in stg_restore_cccs

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1f6c56ae by Andreas Klebinger at 2022-08-06T06:13:17-04:00
StgToCmm: Fix isSimpleScrut when profiling is enabled.

When profiling is enabled we must enter functions that might represent
thunks in order for their sccs to show up in the profile.

We might allocate even if the function is already evaluated in this
case. So we can't consider any potential function thunk to be a simple
scrut when profiling.

Not doing so caused profiled binaries to segfault.

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fab0ee93 by Andreas Klebinger at 2022-08-06T06:13:17-04:00
Change `-fprof-late` to insert cost centres after unfolding creation.

The former behaviour of adding cost centres after optimization but
before unfoldings are created is not available via the flag
`prof-late-inline` instead.

I also reduced the overhead of -fprof-late* by pushing the cost centres
into lambdas. This means the cost centres will only account for
execution of functions and not their partial application.

Further I made LATE_CC cost centres it's own CC flavour so they now
won't clash with user defined ones if a user uses the same string for
a custom scc.

LateCC: Don't put cost centres inside constructor workers.

With -fprof-late they are rarely useful as the worker is usually
inlined. Even if the worker is not inlined or we use -fprof-late-linline
they are generally not helpful but bloat compile and run time
significantly. So we just don't add sccs inside constructor workers.

-------------------------
Metric Decrease:
    T13701
-------------------------

- - - - -
f8bec4e3 by Ben Gamari at 2022-08-06T06:13:53-04:00
gitlab-ci: Fix hadrian bootstrapping of release pipelines

Previously we would attempt to test hadrian bootstrapping in the
`validate` build flavour. However, `ci.sh` refuses to run validation
builds during release pipelines, resulting in job failures. Fix this by
testing bootstrapping in the `release` flavour during release pipelines.

We also attempted to record perf notes for these builds, which is
redundant work and undesirable now since we no longer build in a
consistent flavour.

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c0348865 by Ben Gamari at 2022-08-06T11:45:17-04:00
compiler: Eliminate two uses of foldr in favor of foldl'

These two uses constructed maps, which is a case where foldl' is
generally more efficient since we avoid constructing an intermediate
O(n)-depth stack.

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d2e4e123 by Ben Gamari at 2022-08-06T11:45:17-04:00
rts: Fix code style

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57f530d3 by Ben Gamari at 2022-08-06T11:45:17-04:00
genprimopcode: Drop ArrayArray# references

As ArrayArray# no longer exists

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7267cd52 by Ben Gamari at 2022-08-06T11:45:17-04:00
base: Organize Haddocks in GHC.Conc.Sync

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aa818a9f by Ben Gamari at 2022-08-06T11:48:50-04:00
Add primop to list threads

A user came to #ghc yesterday wondering how best to check whether they
were leaking threads. We ended up using the eventlog but it seems to me
like it would be generally useful if Haskell programs could query their
own threads.

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6d1700b6 by Ben Gamari at 2022-08-06T11:51:35-04:00
rts: Move thread labels into TSO

This eliminates the thread label HashTable and instead tracks this
information in the TSO, allowing us to use proper StgArrBytes arrays for
backing the label and greatly simplifying management of object lifetimes
when we expose them to the user with the coming `threadLabel#` primop.

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1472044b by Ben Gamari at 2022-08-06T11:54:52-04:00
Add a primop to query the label of a thread

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43f2b271 by Ben Gamari at 2022-08-06T11:55:14-04:00
base: Share finalization thread label

For efficiency's sake we float the thread label assigned to the
finalization thread to the top-level, ensuring that we only need to
encode the label once.

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1d63b4fb by Ben Gamari at 2022-08-06T11:57:11-04:00
users-guide: Add release notes entry for thread introspection support

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09bca1de by Ben Gamari at 2022-08-07T01:19:35-04:00
hadrian: Fix binary distribution install attributes

Previously we would use plain `cp` to install various parts of the
binary distribution. However, `cp`'s behavior w.r.t. file attributes is
quite unclear; for this reason it is much better to rather use
`install`.

Fixes #21965.

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2b8ea16d by Ben Gamari at 2022-08-07T01:19:35-04:00
hadrian: Fix installation of system-cxx-std-lib package conf

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7b514848 by Ben Gamari at 2022-08-07T01:20:10-04:00
gitlab-ci: Bump Docker images

To give the ARMv7 job access to lld, fixing #21875.

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afa584a3 by Ben Gamari at 2022-08-07T05:08:52-04:00
hadrian: Don't use mk/config.mk.in

Ultimately we want to drop mk/config.mk so here I extract the bits
needed by the Hadrian bindist installation logic into a Hadrian-specific
file. While doing this I fixed binary distribution installation, #21901.

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b9bb45d7 by Ben Gamari at 2022-08-07T05:08:52-04:00
hadrian: Fix naming of cross-compiler wrappers

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78d04cfa by Ben Gamari at 2022-08-07T11:44:58-04:00
hadrian: Extend xattr Darwin hack to cover /lib

As noted in #21506, it is now necessary to remove extended attributes
from `/lib` as well as `/bin` to avoid SIP issues on Darwin.

Fixes #21506.

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20457d77 by Andreas Klebinger at 2022-08-08T14:42:26+02:00
NCG(x86): Compile add+shift as lea if possible.

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742292e4 by Andreas Klebinger at 2022-08-08T16:46:37-04:00
dataToTag#: Skip runtime tag check if argument is infered tagged

This addresses one part of #21710.

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1504a93e by Cheng Shao at 2022-08-08T16:47:14-04:00
rts: remove redundant stg_traceCcszh

This out-of-line primop has no Haskell wrapper and hasn't been used
anywhere in the tree. Furthermore, the code gets in the way of !7632, so
it should be garbage collected.

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a52de3cb by Andreas Klebinger at 2022-08-08T16:47:50-04:00
Document a divergence from the report in parsing function lhss.

GHC is happy to parse `(f) x y = x + y` when it should be a parse error
based on the Haskell report. Seems harmless enough so we won't fix it
but it's documented now.

Fixes #19788

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5765e133 by Ben Gamari at 2022-08-08T16:48:25-04:00
gitlab-ci: Add release job for aarch64/debian 11

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5b26f324 by Ben Gamari at 2022-08-08T19:39:20-04:00
gitlab-ci: Introduce validation job for aarch64 cross-compilation

Begins to address #11958.

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e866625c by Ben Gamari at 2022-08-08T19:39:20-04:00
Bump process submodule

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ae707762 by Ben Gamari at 2022-08-08T19:39:20-04:00
gitlab-ci: Add basic support for cross-compiler testiing

Here we add a simple qemu-based test for cross-compilers.

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50912d68 by Ben Gamari at 2022-08-08T19:39:57-04:00
rts: Ensure that Array# card arrays are initialized

In #19143 I noticed that newArray# failed to initialize the card table
of newly-allocated arrays. However, embarrassingly, I then only fixed
the issue in newArrayArray# and, in so doing, introduced the potential
for an integer underflow on zero-length arrays (#21962).

Here I fix the issue in newArray#, this time ensuring that we do not
underflow in pathological cases.

Fixes #19143.

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e5ceff56 by Ben Gamari at 2022-08-08T19:39:57-04:00
testsuite: Add test for #21962

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c1c08bd8 by Ben Gamari at 2022-08-09T02:31:14-04:00
gitlab-ci: Don't use coreutils on Darwin

In general we want to ensure that the tested environment is as similar
as possible to the environment the user will use. In the case of Darwin,
this means we want to use the system's BSD command-line utilities, not
coreutils.

This would have caught #21974.

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1c582f44 by Ben Gamari at 2022-08-09T02:31:14-04:00
hadrian: Fix bindist installation on Darwin

It turns out that `cp -P` on Darwin does not always copy a symlink as
a symlink. In order to get these semantics one must pass `-RP`. It's not
entirely clear whether this is valid under POSIX, but it is nevertheless
what Apple does.

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681aa076 by Ben Gamari at 2022-08-09T02:31:49-04:00
hadrian: Fix access mode of installed package registration files

Previously hadrian's bindist Makefile would modify package
registrations placed by `install` via a shell pipeline and `mv`.
However, the use of `mv` means that if umask is set then the user may
otherwise end up with package registrations which are inaccessible.
Fix this by ensuring that the mode is 0644.

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e9dfd26a by Krzysztof Gogolewski at 2022-08-09T02:32:24-04:00
Cleanups around pretty-printing

* Remove hack when printing OccNames. No longer needed since e3dcc0d5
* Remove unused `pprCmms` and `instance Outputable Instr`
* Simplify `pprCLabel` (no need to pass platform)
* Remove evil `Show`/`Eq` instances for `SDoc`. They were needed by
  ImmLit, but that can take just a String instead.
* Remove instance `Outputable CLabel` - proper output of labels
  needs a platform, and is done by the `OutputableP` instance

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66d2e927 by Ben Gamari at 2022-08-09T13:46:48-04:00
rts/linker: Resolve iconv_* on FreeBSD

FreeBSD's libiconv includes an implementation of the
iconv_* functions in libc. Unfortunately these can
only be resolved using dlvsym, which is how the RTS linker
usually resolves such functions. To fix this we include an ad-hoc
special case for iconv_*.

Fixes #20354.

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5d66a0ce by Ben Gamari at 2022-08-09T13:46:48-04:00
system-cxx-std-lib: Add support for FreeBSD libcxxrt

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ea90e61d by Ben Gamari at 2022-08-09T13:46:48-04:00
gitlab-ci: Bump to use freebsd13 runners

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d71a2051 by sheaf at 2022-08-09T13:47:28-04:00
Fix size_up_alloc to account for UnliftedDatatypes

The size_up_alloc function mistakenly considered any type that isn't
lifted to not allocate anything, which is wrong. What we want instead
is to check the type isn't boxed. This accounts for (BoxedRep Unlifted).

Fixes #21939

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d4b6fddb by John Ericson at 2022-08-10T08:25:08+00:00
Relax instances for Functor combinators; put superclass on Class1 to make non-breaking

The first change makes the `Eq`, `Ord`, `Show`, and `Read` instances for
`Sum`, `Product`, and `Compose` match those for `:+:`, `:*:`, and `:.:`.
These have the proper flexible contexts that are exactly what the
instance needs:

For example, instead of
```haskell
instance (Eq1 f, Eq1 g, Eq a) => Eq (Compose f g a) where
  (==) = eq1
```
we do
```haskell
deriving instance Eq (f (g a)) => Eq (Compose f g a)
```

But, that change alone is rather breaking, because until now `Eq (f a)`
and `Eq1 f` (and respectively the other classes and their `*1`
equivalents too) are *incomparable* constraints. This has always been an
annoyance of working with the `*1` classes, and now it would rear it's
head one last time as an pesky migration.

Instead, we give the `*1` classes superclasses, like so:
```haskell
(forall a. Eq a => Eq (f a)) => Eq1 f
```
along with some laws that canonicity is preserved, like:
```haskell
liftEq (==) = (==)
```

and likewise for `*2` classes:
```haskell
(forall a. Eq a => Eq1 (f a)) => Eq2 f
```
and laws:
```haskell
liftEq2 (==) = liftEq1
```

The `*1` classes also have default methods using the `*2` classes where
possible.

What this means, as explained in the docs, is that `*1` classes really
are generations of the regular classes, indicating that the methods can
be split into a canonical lifting combined with a canonical inner, with
the super class "witnessing" the laws[1] in a fashion.

Circling back to the pragmatics of migrating, note that the superclass
means evidence for the old `Sum`, `Product`, and `Compose` instances is
(more than) sufficient, so breakage is less likely --- as long no
instances are "missing", existing polymorphic code will continue to
work.

Breakage can occur when a datatype implements the `*1` class but not the
corresponding regular class, but this is almost certainly an oversight.
For example, containers made that mistake for `Tree` and `Ord`, which I
fixed in https://github.com/haskell/containers/pull/761, but fixing the
issue by adding `Ord1` was extremely *un*controversial.

`Generically1` was also missing `Eq`, `Ord`, `Read,` and `Show`
instances. It is unlikely this would have been caught without
implementing this change.

-----

[1]: In fact, someday, when the laws are part of the language and not
only documentation, we might be able to drop the superclass field of the
dictionary by using the laws to recover the superclass in an
instance-agnostic manner, e.g. with a *non*-overloaded function with
type:

```haskell
DictEq1 f -> DictEq a -> DictEq (f a)
```

But I don't wish to get into optomizations now, just demonstrate the
close relationship between the law and the superclass.

Bump haddock submodule because of test output changing.

- - - - -


30 changed files:

- .gitlab-ci.yml
- .gitlab/ci.sh
- .gitlab/darwin/toolchain.nix
- .gitlab/gen_ci.hs
- .gitlab/jobs.yaml
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/Cmm.hs
- compiler/GHC/Cmm/CLabel.hs
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/Info/Build.hs
- compiler/GHC/Cmm/Sink.hs
- compiler/GHC/CmmToAsm/AArch64/Ppr.hs
- compiler/GHC/CmmToAsm/AArch64/Regs.hs
- compiler/GHC/CmmToAsm/PPC/CodeGen.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/CmmToAsm/PPC/Regs.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/CmmToAsm/X86/Regs.hs
- compiler/GHC/Core/LateCC.hs
- compiler/GHC/Core/Opt/Pipeline.hs
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/Driver/CodeOutput.hs
- compiler/GHC/Driver/Flags.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Iface/Tidy.hs
- compiler/GHC/Stg/InferTags/Rewrite.hs
- compiler/GHC/Stg/Pipeline.hs
- compiler/GHC/StgToCmm/Closure.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e0fc88263659188b0195e64e0a13478ea185273e...d4b6fddba81edb62f4496d55c89781355a9f35a4

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e0fc88263659188b0195e64e0a13478ea185273e...d4b6fddba81edb62f4496d55c89781355a9f35a4
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