[Git][ghc/ghc][wip/T18234] 32 commits: GHC.Core.Unfold: Refactor traceInline

Ben Gamari gitlab at gitlab.haskell.org
Sat May 30 15:46:35 UTC 2020



Ben Gamari pushed to branch wip/T18234 at Glasgow Haskell Compiler / GHC


Commits:
28deee28 by Ben Gamari at 2020-05-28T16:23:21-04:00
GHC.Core.Unfold: Refactor traceInline

This reduces duplication as well as fixes a bug wherein -dinlining-check
would override -ddump-inlinings. Moreover, the new variant

- - - - -
1f393e1e by Ben Gamari at 2020-05-28T16:23:21-04:00
Avoid unnecessary allocations due to tracing utilities

While ticky-profiling the typechecker I noticed that hundreds of
millions of SDocs are being allocated just in case -ddump-*-trace is
enabled. This is awful.

We avoid this by ensuring that the dump flag check is inlined into the
call site, ensuring that the tracing document needn't be allocated
unless it's actually needed.

See Note [INLINE conditional tracing utilities] for details.

Fixes #18168.

Metric Decrease:
  T9961
  haddock.Cabal
  haddock.base
  haddock.compiler

- - - - -
5f621a78 by Vladislav Zavialov at 2020-05-28T16:23:58-04:00
Add Semigroup/Monoid for Q (#18123)

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dc5f004c by Xavier Denis at 2020-05-28T16:24:37-04:00
Fix #18071

Run the core linter on candidate instances to ensure they are
well-kinded.

Better handle quantified constraints by using a CtWanted to avoid
having unsolved constraints thrown away at the end by the solver.

- - - - -
10e6982c by Sebastian Graf at 2020-05-28T16:25:14-04:00
FloatOut: Only eta-expand dead-end RHS if arity will increase (#18231)

Otherwise we risk turning trivial RHS into non-trivial RHS, introducing
unnecessary bindings in the next Simplifier run, resulting in more
churn.

Fixes #18231.

- - - - -
08dab5f7 by Sebastian Graf at 2020-05-28T16:25:14-04:00
DmdAnal: Recognise precise exceptions from case alternatives (#18086)

Consider

```hs
m :: IO ()
m = do
  putStrLn "foo"
  error "bar"
```

`m` (from #18086) always throws a (precise or imprecise) exception or
diverges. Yet demand analysis infers `<L,A>` as demand signature instead
of `<L,A>x` for it.

That's because the demand analyser sees `putStrLn` occuring in a case
scrutinee and decides that it has to `deferAfterPreciseException`,
because `putStrLn` throws a precise exception on some control flow
paths. This will mask the `botDiv` `Divergence`of the single case alt
containing `error` to `topDiv`. Since `putStrLn` has `topDiv` itself,
the final `Divergence` is `topDiv`.

This is easily fixed: `deferAfterPreciseException` works by `lub`ing
with the demand type of a virtual case branch denoting the precise
exceptional control flow. We used `nopDmdType` before, but we can be
more precise and use `exnDmdType`, which is `nopDmdType` with `exnDiv`.

Now the `Divergence` from the case alt will degrade `botDiv` to `exnDiv`
instead of `topDiv`, which combines with the result from the scrutinee
to `exnDiv`, and all is well.

Fixes #18086.

- - - - -
aef95f11 by Ben Gamari at 2020-05-28T16:25:53-04:00
Ticky-ticky: Record DataCon name in ticker name

This makes it significantly easier to spot the nature of
allocations regressions and comes at a reasonably low cost.

- - - - -
8f021b8c by Ben Gamari at 2020-05-28T16:26:34-04:00
hadrian: Don't track GHC's verbosity argument

Teach hadrian to ignore GHC's -v argument in its recompilation check,
thus fixing #18131.

- - - - -
13d9380b by Ben Gamari at 2020-05-28T16:27:20-04:00
Rip out CmmStackInfo(updfr_space)

As noted in #18232, this field is currently completely unused and
moreover doesn't have a clear meaning.

- - - - -
f10d11fa by Andreas Klebinger at 2020-05-29T01:38:42-04:00
Fix "build/elem" RULE.

An redundant constraint prevented the rule from matching.

Fixing this allows a call to elem on a known list to be translated
into a series of equality checks, and eventually a simple case
expression.

Surprisingly this seems to regress elem for strings. To avoid
this we now also allow foldrCString to inline and add an UTF8
variant. This results in elem being compiled to a tight
non-allocating loop over the primitive string literal which
performs a linear search.

In the process this commit adds UTF8 variants for some of the
functions in GHC.CString. This is required to make this work for
both ASCII and UTF8 strings.

There are also small tweaks to the CString related rules.
We now allow ourselfes the luxury to compare the folding function
via eqExpr, which helps to ensure the rule fires before we inline
foldrCString*. Together with a few changes to allow matching on both
the UTF8 and ASCII variants of the CString functions.

- - - - -
bbeb2389 by Ben Gamari at 2020-05-29T01:39:19-04:00
CoreToStg: Add Outputable ArgInfo instance

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0e3361ca by Simon Peyton Jones at 2020-05-29T01:39:19-04:00
Make Lint check return type of a join point

Consider
   join x = rhs in body
It's important that the type of 'rhs' is the same as the type of
'body', but Lint wasn't checking that invariant.

Now it does!  This was exposed by investigation into !3113.

- - - - -
c49f7df0 by Simon Peyton Jones at 2020-05-29T01:39:19-04:00
Do not float join points in exprIsConApp_maybe

We hvae been making exprIsConApp_maybe cleverer in recent times:

    commit b78cc64e923716ac0512c299f42d4d0012306c05
    Date:   Thu Nov 15 17:14:31 2018 +0100
    Make constructor wrappers inline only during the final phase

    commit 7833cf407d1f608bebb1d38bb99d3035d8d735e6
    Date:   Thu Jan 24 17:58:50 2019 +0100
    Look through newtype wrappers (Trac #16254)

    commit c25b135ff5b9c69a90df0ccf51b04952c2dc6ee1
    Date:   Thu Feb 21 12:03:22 2019 +0000
    Fix exprIsConApp_maybe

But alas there was still a bug, now immortalised in
  Note [Don't float join points]
in SimpleOpt.

It's quite hard to trigger because it requires a dead
join point, but it came up when compiling Cabal
Cabal.Distribution.Fields.Lexer.hs, when working on
!3113.

Happily, the fix is extremly easy.  Finding the
bug was not so easy.

- - - - -
46720997 by Ben Gamari at 2020-05-29T01:39:19-04:00
Allow simplification through runRW#

Because runRW# inlines so late, we were previously able to do very
little simplification across it. For instance, given even a simple
program like

    case runRW# (\s -> let n = I# 42# in n) of
      I# n# -> f n#

we previously had no way to avoid the allocation of the I#.

This patch allows the simplifier to push strict contexts into the
continuation of a runRW# application, as explained in
in Note [Simplification of runRW#] in GHC.CoreToStg.Prep.

Fixes #15127.

Metric Increase:
    T9961
Metric Decrease:
    ManyConstructors

Co-Authored-By: Simon Peyton-Jone <simonpj at microsoft.com>

- - - - -
277c2f26 by Ben Gamari at 2020-05-29T01:39:55-04:00
Eta expand un-saturated primops

Now since we no longer try to predict CAFfyness we have no need for the
solution to #16846. Eta expanding unsaturated primop applications is
conceptually simpler, especially in the presence of levity polymorphism.

This essentially reverts cac8dc9f51e31e4c0a6cd9bc302f7e1bc7c03beb,
as suggested in #18079.

Closes #18079.

- - - - -
f44d7ae0 by Simon Jakobi at 2020-05-29T01:40:34-04:00
base: Scrap deprecation plan for Data.Monoid.{First,Last}

See the discussion on the libraries mailing list for context:

https://mail.haskell.org/pipermail/libraries/2020-April/030357.html

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8b494895 by Jeremy Schlatter at 2020-05-29T01:41:12-04:00
Fix typo in documentation

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998450f4 by Gleb Popov at 2020-05-29T01:41:53-04:00
Always define USE_PTHREAD_FOR_ITIMER for FreeBSD.

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f9a513e0 by Alp Mestanogullari at 2020-05-29T01:42:36-04:00
hadrian: introduce 'install' target

Its logic is very simple. It `need`s the `binary-dist-dir` target
and runs suitable `configure` and `make install` commands for the
user. A new `--prefix` command line argument is introduced to
specify where GHC should be installed.

- - - - -
67738db1 by Travis Whitaker at 2020-05-29T13:34:48-04:00
Build a threaded stage 1 if the bootstrapping GHC supports it.

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aac19e6c by Peter Trommler at 2020-05-29T13:35:24-04:00
PPC NCG: No per-symbol .section ".toc" directives

All position independent symbols are collected during code generation
and emitted in one go. Prepending each symbol with a .section ".toc"
directive is redundant. This patch drops the per-symbol directives
leading to smaller assembler files.

Fixes #18250

- - - - -
4413828b by Ben Gamari at 2020-05-30T06:07:31-04:00
rts: Teach getNumProcessors to return available processors

Previously we would report the number of physical processors, which
can be quite wrong in a containerized setting. Now we rather return how
many processors are in our affinity mask when possible.

I also refactored the code to prefer platform-specific since this will
report logical CPUs instead of physical (using
`machdep.cpu.thread_count` on Darwin and `cpuset_getaffinity` on FreeBSD).

Fixes #14781.

- - - - -
1449435c by Ben Gamari at 2020-05-30T06:07:31-04:00
users-guide: Note change in getNumProcessors in users guide

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3d960169 by Ben Gamari at 2020-05-30T06:07:31-04:00
rts: Drop compatibility shims for Windows Vista

We can now assume that the thread and processor group interfaces are
available.

- - - - -
7f8f948c by Peter Trommler at 2020-05-30T06:08:07-04:00
PPC NCG: Fix .size directive on powerpc64 ELF v1

Thanks to Sergei Trofimovich for pointing out the issue.

Fixes #18237

- - - - -
7c555b05 by Andreas Klebinger at 2020-05-30T06:08:43-04:00
Optimize GHC.Utils.Monad.

Many functions in this module are recursive and as such are marked
loop breakers. Which means they are unlikely to get an unfolding.

This is *bad*. We always want to specialize them to specific Monads.
Which requires a visible unfolding at the use site.

I rewrote the recursive ones from:

    foo f x = ... foo x' ...

to

    foo f x = go x
      where
        go x = ...

As well as giving some pragmas to make all of them available
for specialization.

The end result is a reduction of allocations of about -1.4% for
nofib/spectral/simple/Main.hs when compiled with `-O`.

-------------------------
Metric Decrease:
    T12425
    T14683
    T5631
    T9233
    T9675
    T9961
    WWRec
-------------------------

- - - - -
8b1cb5df by Ben Gamari at 2020-05-30T06:09:20-04:00
Windows: Bump Windows toolchain to 0.2

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6947231a by Zubin Duggal at 2020-05-30T06:10:02-04:00
Simplify contexts in GHC.Iface.Ext.Ast

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d23dafab by Sylvain Henry at 2020-05-30T11:46:08-04:00
Hadrian: fix binary-dist target for cross-compilation

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9ea96091 by Ben Gamari at 2020-05-30T11:46:08-04:00
gitlab-ci: Add usage message to ci.sh

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d5e7fd0b by Ben Gamari at 2020-05-30T11:46:08-04:00
gitlab-ci: Make names more consistent

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d58b84f1 by Ben Gamari at 2020-05-30T11:46:29-04:00
gitlab-ci: Introduce a nightly cross-compilation job

This adds a job to test cross-compilation from x86-64 to AArch64 with
Hadrian.

Fixes #18234.

- - - - -


30 changed files:

- .gitlab-ci.yml
- .gitlab/ci.sh
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/PrimOps.hs
- compiler/GHC/ByteCode/Linker.hs
- compiler/GHC/Cmm.hs
- compiler/GHC/Cmm/LayoutStack.hs
- compiler/GHC/Cmm/Ppr.hs
- compiler/GHC/Cmm/ProcPoint.hs
- compiler/GHC/CmmToAsm/PIC.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/Opt/FloatOut.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Monad.hs
- compiler/GHC/Core/SimpleOpt.hs
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/CoreToStg.hs
- compiler/GHC/CoreToStg/Prep.hs
- compiler/GHC/HsToCore/PmCheck/Oracle.hs
- compiler/GHC/HsToCore/Utils.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/Runtime/Eval.hs
- compiler/GHC/StgToCmm/Bind.hs
- compiler/GHC/StgToCmm/Monad.hs
- compiler/GHC/StgToCmm/Ticky.hs
- compiler/GHC/Tc/Solver/Flatten.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/21cb2c3df1cb5857aebd0f5ba69c7f0e19eb1419...d58b84f1f59dfbfcf0f076eab9f1aa054fbe10f6

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