[Git][ghc/ghc][wip/strict-NoExtCon] 32 commits: Clean up "Eta reduction for data families" Notes
Ryan Scott
gitlab at gitlab.haskell.org
Tue Apr 7 23:43:39 UTC 2020
Ryan Scott pushed to branch wip/strict-NoExtCon at Glasgow Haskell Compiler / GHC
Commits:
9b39f2e6 by Ryan Scott at 2020-04-01T01:20:00-04:00
Clean up "Eta reduction for data families" Notes
Before, there were two distinct Notes named
"Eta reduction for data families". This renames one of them to
"Implementing eta reduction for data families" to disambiguate the
two and fixes references in other parts of the codebase to ensure
that they are pointing to the right place.
Fixes #17313.
[ci skip]
- - - - -
7627eab5 by Ryan Scott at 2020-04-01T01:20:38-04:00
Fix the changelog/@since information for hGetContents'/getContents'/readFile'
Fixes #17979.
[ci skip]
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0002db1b by Sylvain Henry at 2020-04-01T01:21:27-04:00
Kill wORDS_BIGENDIAN and replace it with platformByteOrder (#17957)
Metric Decrease:
T13035
T1969
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7b217179 by Sebastian Graf at 2020-04-01T15:03:24-04:00
PmCheck: Adjust recursion depth for inhabitation test
In #17977, we ran into the reduction depth limit of the typechecker.
That was only a symptom of a much broader issue: The recursion depth
of the coverage checker for trying to instantiate strict fields in the
`nonVoid` test was far too high (100, the `defaultMaxTcBound`).
As a result, we were performing quite poorly on `T17977`.
Short of a proper termination analysis to prove emptyness of a type,
we just arbitrarily default to a much lower recursion limit of 3.
Fixes #17977.
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3c09f636 by Andreas Klebinger at 2020-04-01T15:03:59-04:00
Make hadrian pass on the no-colour setting to GHC.
Fixes #17983.
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b943b25d by Simon Peyton Jones at 2020-04-02T01:45:58-04:00
Re-engineer the binder-swap transformation
The binder-swap transformation is implemented by the occurrence
analyser -- see Note [Binder swap] in OccurAnal. However it had
a very nasty corner in it, for the case where the case scrutinee
was a GlobalId. This led to trouble and hacks, and ultimately
to #16296.
This patch re-engineers how the occurrence analyser implements
the binder-swap, by actually carrying out a substitution rather
than by adding a let-binding. It's all described in
Note [The binder-swap substitution].
I did a few other things along the way
* Fix a bug in StgCse, which could allow a loop breaker to be CSE'd
away. See Note [Care with loop breakers] in StgCse. I think it can
only show up if occurrence analyser sets up bad loop breakers, but
still.
* Better commenting in SimplUtils.prepareAlts
* A little refactoring in CoreUnfold; nothing significant
e.g. rename CoreUnfold.mkTopUnfolding to mkFinalUnfolding
* Renamed CoreSyn.isFragileUnfolding to hasCoreUnfolding
* Move mkRuleInfo to CoreFVs
We observed respectively 4.6% and 5.9% allocation decreases for the following
tests:
Metric Decrease:
T9961
haddock.base
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42d68364 by Sebastian Graf at 2020-04-02T01:46:34-04:00
Preserve precise exceptions in strictness analysis
Fix #13380 and #17676 by
1. Changing `raiseIO#` to have `topDiv` instead of `botDiv`
2. Give it special treatment in `Simplifier.Util.mkArgInfo`, treating it
as if it still had `botDiv`, to recover dead code elimination.
This is the first commit of the plan outlined in
https://gitlab.haskell.org/ghc/ghc/-/merge_requests/2525#note_260886.
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0a88dd11 by Ömer Sinan Ağacan at 2020-04-02T01:47:25-04:00
Fix a pointer format string in RTS
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5beac042 by Ömer Sinan Ağacan at 2020-04-02T01:48:05-04:00
Remove unused closure stg_IND_direct
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88f38b03 by Ben Gamari at 2020-04-02T01:48:42-04:00
Session: Memoize stderrSupportsAnsiColors
Not only is this a reasonable efficiency measure but it avoids making
reentrant calls into ncurses, which is not thread-safe. See #17922.
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27740f24 by Ryan Scott at 2020-04-02T01:49:21-04:00
Make Hadrian build with Cabal-3.2
GHC 8.10 ships with `Cabal-3.2.0.0`, so it would be convenient to
make Hadrian supporting building against 3.2.* instead of having to
rebuild the entirety of `Cabal-3.0.0.0`. There is one API change in
`Cabal-3.2.*` that affects Hadrian: the `synopsis` and `description`
functions now return `ShortText` instead of `String`. Since Hadrian
manipulates these `String`s in various places, I found that the
simplest fix was to use CPP to convert `ShortText` to `String`s
where appropriate.
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49802002 by Sylvain Henry at 2020-04-02T01:50:00-04:00
Update Stack resolver for hadrian/build-stack
Broken by 57b888c0e90be7189285a6b078c30b26d0923809
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30a63e79 by Ryan Scott at 2020-04-02T01:50:36-04:00
Fix two ASSERT buglets in reifyDataCon
Two `ASSERT`s in `reifyDataCon` were always using `arg_tys`, but
`arg_tys` is not meaningful for GADT constructors. In fact, it's
worse than non-meaningful, since using `arg_tys` when reifying a
GADT constructor can lead to failed `ASSERT`ions, as #17305
demonstrates.
This patch applies the simplest possible fix to the immediate
problem. The `ASSERT`s now use `r_arg_tys` instead of `arg_tys`, as
the former makes sure to give something meaningful for GADT
constructors. This makes the panic go away at the very least. There
is still an underlying issue with the way the internals of
`reifyDataCon` work, as described in
https://gitlab.haskell.org/ghc/ghc/issues/17305#note_227023, but we
leave that as future work, since fixing the underlying issue is
much trickier (see
https://gitlab.haskell.org/ghc/ghc/issues/17305#note_227087).
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ef7576c4 by Zubin Duggal at 2020-04-03T06:24:56-04:00
Add outputable instances for the types in GHC.Iface.Ext.Types, add -ddump-hie
flag to dump pretty printed contents of the .hie file
Metric Increase:
hie002
Because of the regression on i386:
compile_time/bytes allocated increased from i386-linux-deb9 baseline @ HEAD~10:
Expected hie002 (normal) compile_time/bytes allocated: 583014888.0 +/-10%
Lower bound hie002 (normal) compile_time/bytes allocated: 524713399
Upper bound hie002 (normal) compile_time/bytes allocated: 641316377
Actual hie002 (normal) compile_time/bytes allocated: 877986292
Deviation hie002 (normal) compile_time/bytes allocated: 50.6 %
*** unexpected stat test failure for hie002(normal)
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9462452a by Andreas Klebinger at 2020-04-03T06:25:33-04:00
Improve and refactor StgToCmm codegen for DataCons.
We now differentiate three cases of constructor bindings:
1)Bindings which we can "replace" with a reference to
an existing closure. Reference the replacement closure
when accessing the binding.
2)Bindings which we can "replace" as above. But we still
generate a closure which will be referenced by modules
importing this binding.
3)For any other binding generate a closure. Then reference
it.
Before this patch 1) did only apply to local bindings and we
didn't do 2) at all.
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a214d214 by Moritz Bruder at 2020-04-03T06:26:11-04:00
Add singleton to NonEmpty in libraries/base
This adds a definition to construct a singleton non-empty list
(Data.List.NonEmpty) according to issue #17851.
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f7597aa0 by Sylvain Henry at 2020-04-03T06:26:54-04:00
Testsuite: measure compiler stats for T16190
We were mistakenly measuring program stats
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a485c3c4 by Sylvain Henry at 2020-04-03T06:26:54-04:00
Move blob handling into StgToCmm
Move handling of big literal strings from CmmToAsm to StgToCmm. It
avoids the use of `sdocWithDynFlags` (cf #10143). We might need to move
this handling even higher in the pipeline in the future (cf #17960):
this patch will make it easier.
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cc2918a0 by Sylvain Henry at 2020-04-03T06:26:54-04:00
Refactor CmmStatics
In !2959 we noticed that there was some redundant code (in GHC.Cmm.Utils
and GHC.Cmm.StgToCmm.Utils) used to deal with `CmmStatics` datatype
(before SRT generation) and `RawCmmStatics` datatype (after SRT
generation).
This patch removes this redundant code by using a single GADT for
(Raw)CmmStatics.
- - - - -
9e60273d by Maxim Koltsov at 2020-04-03T06:27:32-04:00
Fix haddock formatting in Control.Monad.ST.Lazy.Imp.hs
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1b7e8a94 by Andreas Klebinger at 2020-04-03T06:28:08-04:00
Turn newlines into spaces for hadrian/ghci.
The newlines break the command on windows.
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4291bdda by Simon Peyton Jones at 2020-04-03T06:28:44-04:00
Major improvements to the specialiser
This patch is joint work of Alexis King and Simon PJ. It does some
significant refactoring of the type-class specialiser. Main highlights:
* We can specialise functions with types like
f :: Eq a => a -> Ord b => b => blah
where the classes aren't all at the front (#16473). Here we can
correctly specialise 'f' based on a call like
f @Int @Bool dEqInt x dOrdBool
This change really happened in an earlier patch
commit 2d0cf6252957b8980d89481ecd0b79891da4b14b
Author: Sandy Maguire <sandy at sandymaguire.me>
Date: Thu May 16 12:12:10 2019 -0400
work that this new patch builds directly on that work, and refactors
it a bit.
* We can specialise functions with implicit parameters (#17930)
g :: (?foo :: Bool, Show a) => a -> String
Previously we could not, but now they behave just like a non-class
argument as in 'f' above.
* We can specialise under-saturated calls, where some (but not all of
the dictionary arguments are provided (#17966). For example, we can
specialise the above 'f' based on a call
map (f @Int dEqInt) xs
even though we don't (and can't) give Ord dictionary.
This may sound exotic, but #17966 is a program from the wild, and
showed significant perf loss for functions like f, if you need
saturation of all dictionaries.
* We fix a buglet in which a floated dictionary had a bogus demand
(#17810), by using zapIdDemandInfo in the NonRec case of specBind.
* A tiny side benefit: we can drop dead arguments to specialised
functions; see Note [Drop dead args from specialisations]
* Fixed a bug in deciding what dictionaries are "interesting"; see
Note [Keep the old dictionaries interesting]
This is all achieved by by building on Sandy Macguire's work in
defining SpecArg, which mkCallUDs uses to describe the arguments of
the call. Main changes:
* Main work is in specHeader, which marched down the [InBndr] from the
function definition and the [SpecArg] from the call site, together.
* specCalls no longer has an arity check; the entire mechanism now
handles unders-saturated calls fine.
* mkCallUDs decides on an argument-by-argument basis whether to
specialise a particular dictionary argument; this is new.
See mk_spec_arg in mkCallUDs.
It looks as if there are many more lines of code, but I think that
all the extra lines are comments!
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40a85563 by Ömer Sinan Ağacan at 2020-04-03T18:26:19+03:00
Revert accidental change in 9462452
[ci skip]
- - - - -
bd75e5da by Ryan Scott at 2020-04-04T07:07:58-04:00
Enable ImpredicativeTypes internally when typechecking selector bindings
This is necessary for certain record selectors with higher-rank
types, such as the examples in #18005. See
`Note [Impredicative record selectors]` in `TcTyDecls`.
Fixes #18005.
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dcfe29c8 by Ömer Sinan Ağacan at 2020-04-06T13:16:08-04:00
Don't override proc CafInfos in ticky builds
Fixes #17947
When we have a ticky label for a proc, IdLabels for the ticky counter
and proc entry share the same Name. This caused overriding proc CafInfos
with the ticky CafInfos (i.e. NoCafRefs) during SRT analysis.
We now ignore the ticky labels when building SRTMaps. This makes sense
because:
- When building the current module they don't need to be in SRTMaps as
they're initialized as non-CAFFY (see mkRednCountsLabel), so they
don't take part in the dependency analysis and they're never added to
SRTs.
(Reminder: a "dependency" in the SRT analysis is a CAFFY dependency,
non-CAFFY uses are not considered as dependencies for the algorithm)
- They don't appear in the interfaces as they're not exported, so it
doesn't matter for cross-module concerns whether they're in the SRTMap
or not.
See also the new Note [Ticky labels in SRT analysis].
- - - - -
cec2c71f by Simon Peyton Jones at 2020-04-06T13:16:44-04:00
Fix an tricky specialiser loop
Issue #17151 was a very tricky example of a bug in which the
specialiser accidentally constructs a recurive dictionary,
so that everything turns into bottom.
I have fixed variants of this bug at least twice before:
see Note [Avoiding loops]. It was a bit of a struggle
to isolate the problem, greatly aided by the work that
Alexey Kuleshevich did in distilling a test case.
Once I'd understood the problem, it was not difficult to fix,
though it did lead me a bit of refactoring in specImports.
- - - - -
e850d14f by Simon Peyton Jones at 2020-04-06T13:16:44-04:00
Refactoring only
This refactors DictBinds into a data type rather than a pair.
No change in behaviour, just better code
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f38e8d61 by Daniel Gröber at 2020-04-07T02:00:05-04:00
rts: ProfHeap: Fix memory leak when not compiled with profiling
If we're doing heap profiling on an unprofiled executable we keep
allocating new space in initEra via nextEra on each profiler run but we
don't have a corresponding freeEra call.
We do free the last era in endHeapProfiling but previous eras will have
been overwritten by initEra and will never get free()ed.
Metric Decrease:
space_leak_001
- - - - -
bcd66859 by Sebastian Graf at 2020-04-07T02:00:41-04:00
Re-export GHC.Magic.noinline from base
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3d2991f8 by Ben Gamari at 2020-04-07T18:36:09-04:00
simplifier: Kill off ufKeenessFactor
We used to have another factor, ufKeenessFactor, which would scale the
discounts before they were subtracted from the size. This was justified
with the following comment:
-- We multiple the raw discounts (args_discount and result_discount)
-- ty opt_UnfoldingKeenessFactor because the former have to do with
-- *size* whereas the discounts imply that there's some extra
-- *efficiency* to be gained (e.g. beta reductions, case reductions)
-- by inlining.
However, this is highly suspect since it means that we subtract a
*scaled* size from an absolute size, resulting in crazy (e.g. negative)
scores in some cases (#15304). We consequently killed off
ufKeenessFactor and bumped up the ufUseThreshold to compensate.
Adjustment of unfolding use threshold
=====================================
Since this removes a discount from our inlining heuristic, I revisited our
default choice of -funfolding-use-threshold to minimize the change in
overall inlining behavior. Specifically, I measured runtime allocations
and executable size of nofib and the testsuite performance tests built
using compilers (and core libraries) built with several values of
-funfolding-use-threshold.
This comes as a result of a quantitative comparison of testsuite
performance and code size as a function of ufUseThreshold, comparing
GHC trees using values of 50, 60, 70, 80, 90, and 100. The test set
consisted of nofib and the testsuite performance tests.
A full summary of these measurements are found in the description of
!2608
Comparing executable sizes (relative to the base commit) across all
nofib tests, we see that sizes are similar to the baseline:
gmean min max median
thresh
50 -6.36% -7.04% -4.82% -6.46%
60 -5.04% -5.97% -3.83% -5.11%
70 -2.90% -3.84% -2.31% -2.92%
80 -0.75% -2.16% -0.42% -0.73%
90 +0.24% -0.41% +0.55% +0.26%
100 +1.36% +0.80% +1.64% +1.37%
baseline +0.00% +0.00% +0.00% +0.00%
Likewise, looking at runtime allocations we see that 80 gives slightly
better optimisation than the baseline:
gmean min max median
thresh
50 +0.16% -0.16% +4.43% +0.00%
60 +0.09% -0.00% +3.10% +0.00%
70 +0.04% -0.09% +2.29% +0.00%
80 +0.02% -1.17% +2.29% +0.00%
90 -0.02% -2.59% +1.86% +0.00%
100 +0.00% -2.59% +7.51% -0.00%
baseline +0.00% +0.00% +0.00% +0.00%
Finally, I had to add a NOINLINE in T4306 to ensure that `upd` is
worker-wrappered as the test expects. This makes me wonder whether the
inlining heuristic is now too liberal as `upd` is quite a large
function. The same measure was taken in T12600.
Wall clock time compiling Cabal with -O0
thresh 50 60 70 80 90 100 baseline
build-Cabal 93.88 89.58 92.59 90.09 100.26 94.81 89.13
Also, this change happens to avoid the spurious test output in
`plugin-recomp-change` and `plugin-recomp-change-prof` (see #17308).
Metric Decrease:
hie002
T12234
T13035
T13719
T14683
T4801
T5631
T5642
T9020
T9872d
T9961
Metric Increase:
T12150
T12425
T13701
T14697
T15426
T1969
T3064
T5837
T6048
T9203
T9872a
T9872b
T9872c
T9872d
haddock.Cabal
haddock.base
haddock.compiler
- - - - -
255418da by Sylvain Henry at 2020-04-07T18:36:49-04:00
Modules: type-checker (#13009)
Update Haddock submodule
- - - - -
04b6cf94 by Ryan Scott at 2020-04-07T19:43:20-04:00
Make NoExtCon fields strict
This changes every unused TTG extension constructor to be strict in
its field so that the pattern-match coverage checker is smart enough
any such constructors are unreachable in pattern matches. This lets
us remove nearly every use of `noExtCon` in the GHC API. The only
ones we cannot remove are ones underneath uses of `ghcPass`, but that
is only because GHC 8.8's and 8.10's coverage checkers weren't smart
enough to perform this kind of reasoning. GHC HEAD's coverage
checker, on the other hand, _is_ smart enough, so we guard these uses
of `noExtCon` with CPP for now.
Bumps the `haddock` submodule.
Fixes #17992.
- - - - -
30 changed files:
- CODEOWNERS
- compiler/GHC.hs
- compiler/GHC/Cmm.hs
- compiler/GHC/Cmm/CLabel.hs
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/Expr.hs
- compiler/GHC/Cmm/Info.hs
- compiler/GHC/Cmm/Info/Build.hs
- compiler/GHC/Cmm/Node.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/Cmm/Ppr/Decl.hs
- compiler/GHC/Cmm/Utils.hs
- compiler/GHC/CmmToAsm/PPC/CodeGen.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/CmmToAsm/PPC/RegInfo.hs
- compiler/GHC/CmmToAsm/Ppr.hs
- compiler/GHC/CmmToAsm/SPARC/CodeGen.hs
- compiler/GHC/CmmToAsm/SPARC/CodeGen/Gen32.hs
- compiler/GHC/CmmToAsm/SPARC/Ppr.hs
- compiler/GHC/CmmToAsm/SPARC/ShortcutJump.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Instr.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/CmmToC.hs
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Data.hs
- compiler/GHC/CmmToLlvm/Ppr.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Arity.hs
- compiler/GHC/Core/Class.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/6ae1e0f5e73c0fd3f81e43d347a9c38f63edc23b...04b6cf947ea065a210a216cc91f918cc1660d430
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/6ae1e0f5e73c0fd3f81e43d347a9c38f63edc23b...04b6cf947ea065a210a216cc91f918cc1660d430
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