[Git][ghc/ghc][wip/T18282] 22 commits: Simplify bindLHsTyVarBndrs and bindHsQTyVars
Ben Gamari
gitlab at gitlab.haskell.org
Thu Jun 11 18:09:32 UTC 2020
Ben Gamari pushed to branch wip/T18282 at Glasgow Haskell Compiler / GHC
Commits:
2dff8141 by Ryan Scott at 2020-06-05T14:21:24-04:00
Simplify bindLHsTyVarBndrs and bindHsQTyVars
Both `bindLHsTyVarBndrs` and `bindHsQTyVars` take two separate
`Maybe` arguments, which I find terribly confusing. Thankfully, it's
possible to remove one `Maybe` argument from each of these functions,
which this patch accomplishes:
* `bindHsQTyVars` takes a `Maybe SDoc` argument, which is `Just` if
GHC should warn about any of the quantified type variables going
unused. However, every call site uses `Nothing` in practice. This
makes sense, since it doesn't really make sense to warn about
unused type variables bound by an `LHsQTyVars`. For instance, you
wouldn't warn about the `a` in `data Proxy a = Proxy` going unused.
As a result, I simply remove this `Maybe SDoc` argument altogether.
* `bindLHsTyVarBndrs` also takes a `Maybe SDoc` argument for the same
reasons that `bindHsQTyVars` took one. To make things more
confusing, however, `bindLHsTyVarBndrs` also takes a separate
`HsDocContext` argument, which is pretty-printed (to an `SDoc`) in
warnings and error messages.
In practice, the `Maybe SDoc` and the `HsDocContext` often contain
the same text. See the call sites for `bindLHsTyVarBndrs` in
`rnFamInstEqn` and `rnConDecl`, for instance. There are only a
handful of call sites where the text differs between the
`Maybe SDoc` and `HsDocContext` arguments:
* In `rnHsRuleDecl`, where the `Maybe SDoc` says "`In the rule`"
and the `HsDocContext` says "`In the transformation rule`".
* In `rnHsTyKi`/`rn_ty`, where the `Maybe SDoc` says
"`In the type`" but the `HsDocContext` is inhereted from the
surrounding context (e.g., if `rnHsTyKi` were called on a
top-level type signature, the `HsDocContext` would be
"`In the type signature`" instead)
In both cases, warnings/error messages arguably _improve_ by
unifying making the `Maybe SDoc`'s text match that of the
`HsDocContext`. As a result, I decided to remove the `Maybe SDoc`
argument to `bindLHsTyVarBndrs` entirely and simply reuse the text
from the `HsDocContext`. (I decided to change the phrase
"transformation rule" to "rewrite rule" while I was in the area.)
The `Maybe SDoc` argument has one other purpose: signaling when to
emit "`Unused quantified type variable`" warnings. To recover this
functionality, I replaced the `Maybe SDoc` argument with a
boolean-like `WarnUnusedForalls` argument. The only
`bindLHsTyVarBndrs` call site that chooses _not_ to emit these
warnings in `bindHsQTyVars`.
- - - - -
e372331b by Ben Gamari at 2020-06-07T08:46:41-04:00
hadrian: Add missing deriveConstants dependency on ghcplatform.h
deriveConstants wants to compile C sources which #include PosixSource.h,
which itself #includes ghcplatform.h. Make sure that Hadrian knows
about this dependency.
Fixes #18290.
- - - - -
b022051a by Moritz Angermann at 2020-06-07T08:46:42-04:00
ghc-prim needs to depend on libc and libm
libm is just an empty shell on musl, and all the math functions are contained in
libc.
- - - - -
6dae6548 by Moritz Angermann at 2020-06-07T08:46:42-04:00
Disable DLL loading if without system linker
Some platforms (musl, aarch64) do not have a working dynamic linker
implemented in the libc, even though we might see dlopen. It will
ultimately just return that this is not supported. Hence we'll add
a flag to the compiler to flat our disable loading dlls. This is
needed as we will otherwise try to load the shared library even
if this will subsequently fail. At that point we have given up
looking for static options though.
- - - - -
4a158ffc by Moritz Angermann at 2020-06-07T08:46:43-04:00
Range is actually +/-2^32, not +/-2^31
See also: https://static.docs.arm.com/ihi0056/g/aaelf64.pdf
- - - - -
f1bfb806 by Ben Gamari at 2020-06-07T10:49:30-04:00
OccurAnal: Avoid exponential behavior due to where clauses
Previously the `Var` case of `occAnalApp` could in some cases (namely
in the case of `runRW#` applications) call `occAnalRhs` two. In the case
of nested `runRW#`s this results in exponential complexity. In some
cases the compilation time that resulted would be very long indeed
(see #18296).
Fixes #18296.
Metric Decrease:
T9961
T12150
T12234
- - - - -
9b607671 by Takenobu Tani at 2020-06-09T08:05:46-04:00
Add link to GHC's wiki in the GHC API header
This adds a URL to point to GHC's wiki in the GHC API header.
Newcomers could easily find more information from the GHC API's
web like [1].
[1]: Current version, https://ghc.gitlab.haskell.org/ghc/doc/libraries/ghc-8.11.0.20200604/index.html
[skip ci]
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72c7fe9a by Ryan Scott at 2020-06-09T08:06:24-04:00
Make GADT constructors adhere to the forall-or-nothing rule properly
Issue #18191 revealed that the types of GADT constructors don't quite
adhere to the `forall`-or-nothing rule. This patch serves to clean up
this sad state of affairs somewhat. The main change is not in the
code itself, but in the documentation, as this patch introduces two
sections to the GHC User's Guide:
* A "Formal syntax for GADTs" section that presents a BNF-style
grammar for what is and isn't allowed in GADT constructor types.
This mostly exists to codify GHC's existing behavior, but it also
imposes a new restriction that addresses #18191: the outermost
`forall` and/or context in a GADT constructor is not allowed to be
surrounded by parentheses. Doing so would make these
`forall`s/contexts nested, and GADTs do not support nested
`forall`s/contexts at present.
* A "`forall`-or-nothing rule" section that describes exactly what
the `forall`-or-nothing rule is all about. Surprisingly, there was
no mention of this anywhere in the User's Guide up until now!
To adhere the new specification in the "Formal syntax for GADTs"
section of the User's Guide, the following code changes were made:
* A new function, `GHC.Hs.Type.splitLHsGADTPrefixTy`, was introduced.
This is very much like `splitLHsSigmaTy`, except that it avoids
splitting apart any parentheses, which can be syntactically
significant for GADT types. See
`Note [No nested foralls or contexts in GADT constructors]` in
`GHC.Hs.Type`.
* `ConDeclGADTPrefixPs`, an extension constructor for `XConDecl`, was
introduced so that `GHC.Parser.PostProcess.mkGadtDecl` can return
it when given a prefix GADT constructor. Unlike `ConDeclGADT`,
`ConDeclGADTPrefixPs` does not split the GADT type into its argument
and result types, as this cannot be done until after the type is
renamed (see `Note [GADT abstract syntax]` in `GHC.Hs.Decls` for why
this is the case).
* `GHC.Renamer.Module.rnConDecl` now has an additional case for
`ConDeclGADTPrefixPs` that (1) splits apart the full `LHsType` into
its `forall`s, context, argument types, and result type, and
(2) checks for nested `forall`s/contexts. Step (2) used to be
performed the typechecker (in `GHC.Tc.TyCl.badDataConTyCon`) rather
than the renamer, but now the relevant code from the typechecker
can simply be deleted.
One nice side effect of this change is that we are able to give a
more accurate error message for GADT constructors that use visible
dependent quantification (e.g., `MkFoo :: forall a -> a -> Foo a`),
which improves the stderr in the `T16326_Fail6` test case.
Fixes #18191. Bumps the Haddock submodule.
- - - - -
a47e6442 by Ryan Scott at 2020-06-10T03:39:12-04:00
Always use rnImplicitBndrs to bring implicit tyvars into scope
This implements a first step towards #16762 by changing the renamer
to always use `rnImplicitBndrs` to bring implicitly bound type
variables into scope. The main change is in `rnFamInstEqn` and
`bindHsQTyVars`, which previously used _ad hoc_ methods of binding
their implicit tyvars.
There are a number of knock-on consequences:
* One of the reasons that `rnFamInstEqn` used an _ad hoc_ binding
mechanism was to give more precise source locations in
`-Wunused-type-patterns` warnings. (See
https://gitlab.haskell.org/ghc/ghc/issues/16762#note_273343 for an
example of this.) However, these warnings are actually a little
_too_ precise, since implicitly bound type variables don't have
exact binding sites like explicitly bound type variables do.
A similar problem existed for
"`Different names for the same type variable`" errors involving
implicit tyvars bound by `bindHsQTyVars`.
Therefore, we simply accept the less precise (but more accurate)
source locations from `rnImplicitBndrs` in `rnFamInstEqn` and
`bindHsQTyVars`. See
`Note [Source locations for implicitly bound type variables]` in
`GHC.Rename.HsType` for the full story.
* In order for `rnImplicitBndrs` to work in `rnFamInstEqn`, it needs
to be able to look up names from the parent class (in the event
that we are renaming an associated type family instance). As a
result, `rnImplicitBndrs` now takes an argument of type
`Maybe assoc`, which is `Just` in the event that a type family
instance is associated with a class.
* Previously, GHC kept track of three type synonyms for free type
variables in the renamer: `FreeKiTyVars`, `FreeKiTyVarsDups`
(which are allowed to contain duplicates), and
`FreeKiTyVarsNoDups` (which contain no duplicates). However, making
is a distinction between `-Dups` and `-NoDups` is now pointless, as
all code that returns `FreeKiTyVars{,Dups,NoDups}` will eventually
end up being passed to `rnImplicitBndrs`, which removes duplicates.
As a result, I decided to just get rid of `FreeKiTyVarsDups` and
`FreeKiTyVarsNoDups`, leaving only `FreeKiTyVars`.
* The `bindLRdrNames` and `deleteBys` functions are now dead code, so
I took the liberty of removing them.
- - - - -
24879129 by Takenobu Tani at 2020-06-10T03:39:59-04:00
Clarify leaf module names for new module hierarchy
This updates comments only.
This patch replaces leaf module names according to new module
hierarchy [1][2] as followings:
* Expand leaf names to easily find the module path:
for instance, `Id.hs` to `GHC.Types.Id`.
* Modify leaf names according to new module hierarchy:
for instance, `Convert.hs` to `GHC.ThToHs`.
* Fix typo:
for instance, `GHC.Core.TyCo.Rep.hs` to `GHC.Core.TyCo.Rep`
See also !3375
[1]: https://gitlab.haskell.org/ghc/ghc/-/wikis/Make-GHC-codebase-more-modular
[2]: https://gitlab.haskell.org/ghc/ghc/issues/13009
- - - - -
92de9e25 by Ömer Sinan Ağacan at 2020-06-10T03:41:07-04:00
rts: Remove unused GET_ENTRY closure macro
This macro is not used and got broken in the meantime, as ENTRY_CODE was
deleted.
- - - - -
87102928 by Ömer Sinan Ağacan at 2020-06-10T03:41:50-04:00
Fix -fkeep-cafs flag name in users guide
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ccd6843d by Shayne Fletcher at 2020-06-10T04:14:57-04:00
Expose impliedGFlags, impledOffGFlags, impliedXFlags
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7a737e89 by Ömer Sinan Ağacan at 2020-06-10T04:14:58-04:00
Cross-module LambdaFormInfo passing
- Store LambdaFormInfos of exported Ids in interface files
- Use them in importing modules
This is for optimization purposes: if we know LambdaFormInfo of imported
Ids we can generate more efficient calling code, see `getCallMethod`.
Exporting (putting them in interface files or in ModDetails) and
importing (reading them from interface files) are both optional. We
don't assume known LambdaFormInfos anywhere and do not change how we
call Ids with unknown LambdaFormInfos.
Runtime, allocation, and residency numbers when building
Cabal-the-library (commit 0d4ee7ba3):
(Log and .hp files are in the MR: !2842)
| | GHC HEAD | This patch | Diff |
|-----|----------|------------|----------------|
| -O0 | 0:35.89 | 0:34.10 | -1.78s, -4.98% |
| -O1 | 2:24.01 | 2:23.62 | -0.39s, -0.27% |
| -O2 | 2:52.23 | 2:51.35 | -0.88s, -0.51% |
| | GHC HEAD | This patch | Diff |
|-----|-----------------|-----------------|----------------------------|
| -O0 | 54,843,608,416 | 54,878,769,544 | +35,161,128 bytes, +0.06% |
| -O1 | 227,136,076,400 | 227,569,045,168 | +432,968,768 bytes, +0.19% |
| -O2 | 266,147,063,296 | 266,749,643,440 | +602,580,144 bytes, +0.22% |
NOTE: Residency is measured with extra runtime args: `-i0 -h` which effectively
turn all GCs into major GCs, and do GC more often.
| | GHC HEAD | This patch | Diff |
|-----|----------------------------|------------------------------|----------------------------|
| -O0 | 410,284,000 (910 samples) | 411,745,008 (906 samples) | +1,461,008 bytes, +0.35% |
| -O1 | 928,580,856 (2109 samples) | 943,506,552 (2103 samples) | +14,925,696 bytes, +1.60% |
| -O2 | 993,951,352 (2549 samples) | 1,010,156,328 (2545 samples) | +16,204,9760 bytes, +1.63% |
NoFib results:
--------------------------------------------------------------------------------
Program Size Allocs Instrs Reads Writes
--------------------------------------------------------------------------------
CS 0.0% 0.0% +0.0% +0.0% +0.0%
CSD 0.0% 0.0% 0.0% +0.0% +0.0%
FS 0.0% 0.0% +0.0% +0.0% +0.0%
S 0.0% 0.0% +0.0% +0.0% +0.0%
VS 0.0% 0.0% +0.0% +0.0% +0.0%
VSD 0.0% 0.0% +0.0% +0.0% +0.1%
VSM 0.0% 0.0% +0.0% +0.0% +0.0%
anna 0.0% 0.0% -0.3% -0.8% -0.0%
ansi 0.0% 0.0% -0.0% -0.0% 0.0%
atom 0.0% 0.0% -0.0% -0.0% 0.0%
awards 0.0% 0.0% -0.1% -0.3% 0.0%
banner 0.0% 0.0% -0.0% -0.0% -0.0%
bernouilli 0.0% 0.0% -0.0% -0.0% -0.0%
binary-trees 0.0% 0.0% -0.0% -0.0% +0.0%
boyer 0.0% 0.0% -0.0% -0.0% 0.0%
boyer2 0.0% 0.0% -0.0% -0.0% 0.0%
bspt 0.0% 0.0% -0.0% -0.2% 0.0%
cacheprof 0.0% 0.0% -0.1% -0.4% +0.0%
calendar 0.0% 0.0% -0.0% -0.0% 0.0%
cichelli 0.0% 0.0% -0.9% -2.4% 0.0%
circsim 0.0% 0.0% -0.0% -0.0% 0.0%
clausify 0.0% 0.0% -0.1% -0.3% 0.0%
comp_lab_zift 0.0% 0.0% -0.0% -0.0% +0.0%
compress 0.0% 0.0% -0.0% -0.0% -0.0%
compress2 0.0% 0.0% -0.0% -0.0% 0.0%
constraints 0.0% 0.0% -0.1% -0.2% -0.0%
cryptarithm1 0.0% 0.0% -0.0% -0.0% 0.0%
cryptarithm2 0.0% 0.0% -1.4% -4.1% -0.0%
cse 0.0% 0.0% -0.0% -0.0% -0.0%
digits-of-e1 0.0% 0.0% -0.0% -0.0% -0.0%
digits-of-e2 0.0% 0.0% -0.0% -0.0% -0.0%
dom-lt 0.0% 0.0% -0.1% -0.2% 0.0%
eliza 0.0% 0.0% -0.5% -1.5% 0.0%
event 0.0% 0.0% -0.0% -0.0% -0.0%
exact-reals 0.0% 0.0% -0.1% -0.3% +0.0%
exp3_8 0.0% 0.0% -0.0% -0.0% -0.0%
expert 0.0% 0.0% -0.3% -1.0% -0.0%
fannkuch-redux 0.0% 0.0% +0.0% +0.0% +0.0%
fasta 0.0% 0.0% -0.0% -0.0% +0.0%
fem 0.0% 0.0% -0.0% -0.0% 0.0%
fft 0.0% 0.0% -0.0% -0.0% 0.0%
fft2 0.0% 0.0% -0.0% -0.0% 0.0%
fibheaps 0.0% 0.0% -0.0% -0.0% +0.0%
fish 0.0% 0.0% 0.0% -0.0% +0.0%
fluid 0.0% 0.0% -0.4% -1.2% +0.0%
fulsom 0.0% 0.0% -0.0% -0.0% 0.0%
gamteb 0.0% 0.0% -0.1% -0.3% 0.0%
gcd 0.0% 0.0% -0.0% -0.0% 0.0%
gen_regexps 0.0% 0.0% -0.0% -0.0% -0.0%
genfft 0.0% 0.0% -0.0% -0.0% 0.0%
gg 0.0% 0.0% -0.0% -0.0% +0.0%
grep 0.0% 0.0% -0.0% -0.0% -0.0%
hidden 0.0% 0.0% -0.1% -0.4% -0.0%
hpg 0.0% 0.0% -0.2% -0.5% +0.0%
ida 0.0% 0.0% -0.0% -0.0% +0.0%
infer 0.0% 0.0% -0.3% -0.8% -0.0%
integer 0.0% 0.0% -0.0% -0.0% +0.0%
integrate 0.0% 0.0% -0.0% -0.0% 0.0%
k-nucleotide 0.0% 0.0% -0.0% -0.0% +0.0%
kahan 0.0% 0.0% -0.0% -0.0% +0.0%
knights 0.0% 0.0% -2.2% -5.4% 0.0%
lambda 0.0% 0.0% -0.6% -1.8% 0.0%
last-piece 0.0% 0.0% -0.0% -0.0% 0.0%
lcss 0.0% 0.0% -0.0% -0.1% 0.0%
life 0.0% 0.0% -0.0% -0.1% 0.0%
lift 0.0% 0.0% -0.2% -0.6% +0.0%
linear 0.0% 0.0% -0.0% -0.0% -0.0%
listcompr 0.0% 0.0% -0.0% -0.0% 0.0%
listcopy 0.0% 0.0% -0.0% -0.0% 0.0%
maillist 0.0% 0.0% -0.1% -0.3% +0.0%
mandel 0.0% 0.0% -0.0% -0.0% 0.0%
mandel2 0.0% 0.0% -0.0% -0.0% -0.0%
mate +0.0% 0.0% -0.0% -0.0% -0.0%
minimax 0.0% 0.0% -0.2% -1.0% 0.0%
mkhprog 0.0% 0.0% -0.1% -0.2% -0.0%
multiplier 0.0% 0.0% -0.0% -0.0% -0.0%
n-body 0.0% 0.0% -0.0% -0.0% +0.0%
nucleic2 0.0% 0.0% -0.1% -0.2% 0.0%
para 0.0% 0.0% -0.0% -0.0% -0.0%
paraffins 0.0% 0.0% -0.0% -0.0% 0.0%
parser 0.0% 0.0% -0.2% -0.7% 0.0%
parstof 0.0% 0.0% -0.0% -0.0% +0.0%
pic 0.0% 0.0% -0.0% -0.0% 0.0%
pidigits 0.0% 0.0% +0.0% +0.0% +0.0%
power 0.0% 0.0% -0.2% -0.6% +0.0%
pretty 0.0% 0.0% -0.0% -0.0% -0.0%
primes 0.0% 0.0% -0.0% -0.0% 0.0%
primetest 0.0% 0.0% -0.0% -0.0% -0.0%
prolog 0.0% 0.0% -0.3% -1.1% 0.0%
puzzle 0.0% 0.0% -0.0% -0.0% 0.0%
queens 0.0% 0.0% -0.0% -0.0% +0.0%
reptile 0.0% 0.0% -0.0% -0.0% 0.0%
reverse-complem 0.0% 0.0% -0.0% -0.0% +0.0%
rewrite 0.0% 0.0% -0.7% -2.5% -0.0%
rfib 0.0% 0.0% -0.0% -0.0% 0.0%
rsa 0.0% 0.0% -0.0% -0.0% 0.0%
scc 0.0% 0.0% -0.1% -0.2% -0.0%
sched 0.0% 0.0% -0.0% -0.0% -0.0%
scs 0.0% 0.0% -1.0% -2.6% +0.0%
simple 0.0% 0.0% +0.0% -0.0% +0.0%
solid 0.0% 0.0% -0.0% -0.0% 0.0%
sorting 0.0% 0.0% -0.6% -1.6% 0.0%
spectral-norm 0.0% 0.0% +0.0% 0.0% +0.0%
sphere 0.0% 0.0% -0.0% -0.0% -0.0%
symalg 0.0% 0.0% -0.0% -0.0% +0.0%
tak 0.0% 0.0% -0.0% -0.0% 0.0%
transform 0.0% 0.0% -0.0% -0.0% 0.0%
treejoin 0.0% 0.0% -0.0% -0.0% 0.0%
typecheck 0.0% 0.0% -0.0% -0.0% +0.0%
veritas +0.0% 0.0% -0.2% -0.4% +0.0%
wang 0.0% 0.0% -0.0% -0.0% 0.0%
wave4main 0.0% 0.0% -0.0% -0.0% -0.0%
wheel-sieve1 0.0% 0.0% -0.0% -0.0% -0.0%
wheel-sieve2 0.0% 0.0% -0.0% -0.0% +0.0%
x2n1 0.0% 0.0% -0.0% -0.0% -0.0%
--------------------------------------------------------------------------------
Min 0.0% 0.0% -2.2% -5.4% -0.0%
Max +0.0% 0.0% +0.0% +0.0% +0.1%
Geometric Mean -0.0% -0.0% -0.1% -0.3% +0.0%
Metric increases micro benchmarks tracked in #17686:
Metric Increase:
T12150
T12234
T12425
T13035
T5837
T6048
T9233
Co-authored-by: Andreas Klebinger <klebinger.andreas at gmx.at>
- - - - -
3b22b14a by Shayne Fletcher at 2020-06-10T04:15:01-04:00
Give Language a Bounded instance
- - - - -
9454511b by Simon Peyton Jones at 2020-06-10T04:17:06-04:00
Optimisation in Unique.Supply
This patch switches on -fno-state-hack in GHC.Types.Unique.Supply.
It turned out that my fixes for #18078 (coercion floating) changed the
optimisation pathway for mkSplitUniqSupply in such a way that we had
an extra allocation inside the inner loop. Adding -fno-state-hack
fixed that -- and indeed the loop in mkSplitUniqSupply is a classic
example of the way in which -fno-state-hack can be bad; see #18238.
Moreover, the new code is better than the old. They allocate
the same, but the old code ends up with a partial application.
The net effect is that the test
perf/should_run/UniqLoop
runs 20% faster! From 2.5s down to 2.0s. The allocation numbers
are the same -- but elapsed time falls. Good!
The bad thing about this is that it's terribly delicate. But
at least it's a good example of such delicacy in action.
There is a long Note [Optimising the unique supply] which now
explains all this.
- - - - -
6d49d5be by Simon Peyton Jones at 2020-06-10T04:17:06-04:00
Implement cast worker/wrapper properly
The cast worker/wrapper transformation transforms
x = e |> co
into
y = e
x = y |> co
This is done by the simplifier, but we were being
careless about transferring IdInfo from x to y,
and about what to do if x is a NOINLNE function.
This resulted in a series of bugs:
#17673, #18093, #18078.
This patch fixes all that:
* Main change is in GHC.Core.Opt.Simplify, and
the new prepareBinding function, which does this
cast worker/wrapper transform.
See Note [Cast worker/wrappers].
* There is quite a bit of refactoring around
prepareRhs, makeTrivial etc. It's nicer now.
* Some wrappers from strictness and cast w/w, notably those for
a function with a NOINLINE, should inline very late. There
wasn't really a mechanism for that, which was an existing bug
really; so I invented a new finalPhase = Phase (-1). It's used
for all simplifier runs after the user-visible phase 2,1,0 have
run. (No new runs of the simplifier are introduced thereby.)
See new Note [Compiler phases] in GHC.Types.Basic;
the main changes are in GHC.Core.Opt.Driver
* Doing this made me trip over two places where the AnonArgFlag on a
FunTy was being lost so we could end up with (Num a -> ty)
rather than (Num a => ty)
- In coercionLKind/coercionRKind
- In contHoleType in the Simplifier
I fixed the former by defining mkFunctionType and using it in
coercionLKind/RKind.
I could have done the same for the latter, but the information
is almost to hand. So I fixed the latter by
- adding sc_hole_ty to ApplyToVal (like ApplyToTy),
- adding as_hole_ty to ValArg (like TyArg)
- adding sc_fun_ty to StrictArg
Turned out I could then remove ai_type from ArgInfo. This is
just moving the deck chairs around, but it worked out nicely.
See the new Note [AnonArgFlag] in GHC.Types.Var
* When looking at the 'arity decrease' thing (#18093) I discovered
that stable unfoldings had a much lower arity than the actual
optimised function. That's what led to the arity-decrease
message. Simple solution: eta-expand.
It's described in Note [Eta-expand stable unfoldings]
in GHC.Core.Opt.Simplify
* I also discovered that unsafeCoerce wasn't being inlined if
the context was boring. So (\x. f (unsafeCoerce x)) would
create a thunk -- yikes! I fixed that by making inlineBoringOK
a bit cleverer: see Note [Inline unsafeCoerce] in GHC.Core.Unfold.
I also found that unsafeCoerceName was unused, so I removed it.
I made a test case for #18078, and a very similar one for #17673.
The net effect of all this on nofib is very modest, but positive:
--------------------------------------------------------------------------------
Program Size Allocs Runtime Elapsed TotalMem
--------------------------------------------------------------------------------
anna -0.4% -0.1% -3.1% -3.1% 0.0%
fannkuch-redux -0.4% -0.3% -0.1% -0.1% 0.0%
maillist -0.4% -0.1% -7.8% -1.0% -14.3%
primetest -0.4% -15.6% -7.1% -6.6% 0.0%
--------------------------------------------------------------------------------
Min -0.9% -15.6% -13.3% -14.2% -14.3%
Max -0.3% 0.0% +12.1% +12.4% 0.0%
Geometric Mean -0.4% -0.2% -2.3% -2.2% -0.1%
All following metric decreases are compile-time allocation decreases
between -1% and -3%:
Metric Decrease:
T5631
T13701
T14697
T15164
- - - - -
32fd37f5 by Luke Lau at 2020-06-10T04:17:22-04:00
Fix lookupGlobalOccRn_maybe sometimes reporting an error
In some cases it was possible for lookupGlobalOccRn_maybe to return an
error, when it should be returning a Nothing. If it called
lookupExactOcc_either when there were no matching GlobalRdrElts in the
otherwise case, it would return an error message. This could be caused
when lookupThName_maybe in Template Haskell was looking in different
namespaces (thRdrNameGuesses), guessing different namespaces that the
name wasn't guaranteed to be found in.
However, by addressing this some more accurate errors were being lost in
the conversion to Maybes. So some of the lookup* functions have been
shuffled about so that errors should always be ignored in
lookup*_maybes, and propagated otherwise.
This fixes #18263
- - - - -
9b283e1b by Roland Senn at 2020-06-10T04:17:34-04:00
Initialize the allocation counter in GHCi to 0 (Fixes #16012)
According to the documentation for the function `getAllocationCounter` in
[System.Mem](http://hackage.haskell.org/package/base-4.14.0.0/docs/System-Mem.html)
initialize the allocationCounter also in GHCi to 0.
- - - - -
8d07c48c by Sylvain Henry at 2020-06-10T04:17:36-04:00
test: fix conc038
We had spurious failures of conc038 test on CI with stdout:
```
newThread started
-mainThread
-Haskell: 2
newThread back again
+mainThread
1 sec later
shutting down
+Haskell: 2
```
- - - - -
b7c80e61 by Simon Peyton Jones at 2020-06-11T14:09:29-04:00
Reduce result discount in conSize
Ticket #18282 showed that the result discount given by conSize
was massively too large. This patch reduces that discount to
a constant 10, which just balances the cost of the constructor
application itself.
Note [Constructor size and result discount] elaborates, as
does the ticket #18282.
Reducing result discount reduces inlining, which affects perf. I
found that I could increase the unfoldingUseThrehold from 80 to 90 in
compensation; in combination with the result discount change I get
these overall nofib numbers:
Program Size Allocs Runtime Elapsed TotalMem
--------------------------------------------------------------------------------
boyer -0.3% +5.4% +0.7% +1.0% 0.0%
cichelli -0.3% +5.9% -9.9% -9.5% 0.0%
compress2 -0.4% +9.6% +7.2% +6.4% 0.0%
constraints -0.3% +0.2% -3.0% -3.4% 0.0%
cryptarithm2 -0.3% -3.9% -2.2% -2.4% 0.0%
gamteb -0.4% +2.5% +2.8% +2.8% 0.0%
life -0.3% -2.2% -4.7% -4.9% 0.0%
lift -0.3% -0.3% -0.8% -0.5% 0.0%
linear -0.3% -0.1% -4.1% -4.5% 0.0%
mate -0.2% +1.4% -2.2% -1.9% -14.3%
parser -0.3% -2.1% -5.4% -4.6% 0.0%
puzzle -0.3% +2.1% -6.6% -6.3% 0.0%
simple -0.4% +2.8% -3.4% -3.3% -2.2%
veritas -0.1% +0.7% -0.6% -1.1% 0.0%
wheel-sieve2 -0.3% -19.2% -24.9% -24.5% -42.9%
--------------------------------------------------------------------------------
Min -0.4% -19.2% -24.9% -24.5% -42.9%
Max +0.1% +9.6% +7.2% +6.4% +33.3%
Geometric Mean -0.3% -0.0% -3.0% -2.9% -0.3%
I'm ok with these numbers, remembering that this change removes
an *exponential* increase in code size in some in-the-wild cases.
I investigated compress2. The difference is entirely caused by this
function no longer inlining
WriteRoutines.$woutputCodes
= \ (w :: [CodeEvent]) ->
let result_s1Sr
= case WriteRoutines.outputCodes_$s$woutput w 0# 0# 8# 9# of
(# ww1, ww2 #) -> (ww1, ww2)
in (# case result_s1Sr of (x, _) ->
map @Int @Char WriteRoutines.outputCodes1 x
, case result_s1Sr of { (_, y) -> y } #)
It was right on the cusp before, driven by the excessive result
discount. Too bad!
Metric Decrease:
T12227
T12545
T15263
T1969
T5030
T9872a
T9872c
Metric Increase:
T13701
T9872d
- - - - -
dd0ae044 by Simon Peyton Jones at 2020-06-11T14:09:29-04:00
Perf wibbles
Document before committing
- - - - -
30 changed files:
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/Node.hs
- compiler/GHC/Cmm/Ppr/Expr.hs
- compiler/GHC/CmmToAsm.hs
- compiler/GHC/CmmToAsm/CFG.hs
- compiler/GHC/CmmToAsm/Dwarf.hs
- compiler/GHC/CmmToAsm/Monad.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/CmmToAsm/SPARC/Ppr.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/CmmToLlvm/Data.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion/Axiom.hs
- compiler/GHC/Core/FVs.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Opt/CSE.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/Driver.hs
- compiler/GHC/Core/Opt/FloatIn.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7d7c2dc7fceee763b4f292466488892cf4b6ca5a...dd0ae04476ab92dfad75875b03e1b7bdb5992c49
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7d7c2dc7fceee763b4f292466488892cf4b6ca5a...dd0ae04476ab92dfad75875b03e1b7bdb5992c49
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