| Commit message (Collapse) | Author | Age | Files | Lines |
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The reasons for that can be found in the wiki:
https://gitlab.haskell.org/ghc/ghc/wikis/nested-cpr/split-off-cpr
We now run CPR after demand analysis (except for after the final demand
analysis run just before code gen). CPR got its own dump flags
(`-ddump-cpr-anal`, `-ddump-cpr-signatures`), but not its own flag to
activate/deactivate. It will run with `-fstrictness`/`-fworker-wrapper`.
As explained on the wiki page, this step is necessary for a sane Nested
CPR analysis. And it has quite positive impact on compiler performance:
Metric Decrease:
T9233
T9675
T9961
T15263
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See https://gitlab.haskell.org/ghc/ghc/issues/17801#note_253330
No regression test, as it's hard to trigger.
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Update haddock submodule
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There is no issue with nested splices as they do not require any compile
time code execution. All execution is delayed until the top-level
splice.
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This documentation-only patch fixes #17793
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Previously, we would accidentally make constraints like
forall a. C a => forall b. D b => E a b c as we traversed
superclasses. No longer!
This patch also expands Note [Eagerly expand given superclasses]
to work over quantified constraints; necessary for T16502b.
Close #17202 and #16502.
test cases: typecheck/should_compile/T{17202,16502{,b}}
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For record updates where the `record_expr` is a variable, as in #17783:
```hs
data PartialRec = No
| Yes { a :: Int, b :: Bool }
update No = No
update r@(Yes {}) = r { b = False }
```
We should make use of long distance info in
`-Wincomplete-record-updates` checking. But the call to `matchWrapper`
in the `RecUpd` case didn't specify a scrutinee expression, which would
correspond to the `record_expr` `r` here. That is fixed now.
Fixes #17783.
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Once again make sure this dumps the STG used for codegen.
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This patch implements the [sugggestion from Simon (PJ)](https://gitlab.haskell.org/ghc/ghc/issues/14628#note_146559):
- Make `TcErrors.getSkolemInfo` return a `SkolemInfo` rather than an `Implication`.
- If `getSkolemInfo` gets `RuntimeUnk`s, just return a new data constructor in `SkolemInfo`, called `RuntimeUnkSkol`.
- In `TcErrors.pprSkols` print something sensible for a `RuntimeUnkSkol`.
The `getSkolemInfo` function paniced while formating suggestions to add type annotations (subfunction `suggestAddSig`)
to a *"Couldn't match type ‘x’ with ‘y’"* error message.
The `getSkolemInfo` function didn't find any Implication value and paniced.
With this patch the `getSkolemInfo` function does no longer panic, if it finds `RuntimeUnkSkol`s.
As the panic occured while processing an error message, we don't need to implement any new error message!
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This link appears to have been forgotten in
0dad81ca5fd1f63bf8a3b6ad09787559e8bd05c0 .
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This is in preparation of backwards-incompatible changes in happy.
See https://github.com/simonmar/happy/issues/166
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cc/ @pepeiborra
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This alternative is redundant and triggers no warning when building with 8.6.5
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This implements the warning proposed in option (B) of the
Data.List.singleton CLC [discussion][].
This warning, which is included in `-Wcompat` is intended to help users
identify imports of modules that will change incompatibly in future GHC
releases. This currently only includes `Data.List` due to the expected
specialisation and addition of `Data.List.singleton`.
Fixes #17244.
[discussion]: https://groups.google.com/d/msg/haskell-core-libraries/q3zHLmzBa5E/PmlAs_kYAQAJ
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There are two main payloads of this patch:
1. This introduces IsPass, which allows e.g. printing
code to ask what pass it is running in (Renamed vs
Typechecked) and thus print extension fields. See
Note [IsPass] in Hs.Extension
2. This moves the HsWrap constructor into an extension
field, where it rightly belongs. This is done for
HsExpr and HsCmd, but not for HsPat, which is left
as an exercise for the reader.
There is also some refactoring around SyntaxExprs, but this
is really just incidental.
This patch subsumes !1721 (sorry @chreekat).
Along the way, there is a bit of refactoring in GHC.Hs.Extension,
including the removal of NameOrRdrName in favor of NoGhcTc.
This meant that we had no real need for GHC.Hs.PlaceHolder, so
I got rid of it.
Updates haddock submodule.
-------------------------
Metric Decrease:
haddock.compiler
-------------------------
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```
main = do
print $ g [1..100] a
where g xs x = map (`mod` x) xs
a :: Int = 324
```
The above program previously attributed the cost of computing 324 to a cost
centre named `(...)`, with this change the cost is attributed to `a` instead.
This change only affects simple pattern bindings (decorated variables: type
signatures, parens, ~ annotations and ! annotations).
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This entailed
* Adding a tcf_view field to TyCoFolder
* Moving exactTyCoVarsOtType to TcType. It properly belongs
there, since only the typechecker calls this function. But
it also means that we can "see" and inline tcView.
Metric Decrease:
T14683
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This patch delivers on (much of) #17509.
* Introduces the shallow vs deep free variable distinction
* Introduce TyCoRep.foldType,
foldType :: Monoid a => TyCoFolder env a
-> env -> Type -> a
and use it in the free variable finders.
* Substitution in TyCoSubst
* ASSERTs are on for checkValidSubst
* checkValidSubst uses shallowTyCoVarsOfTypes etc
Quite a few things still to do
* We could use foldType in lots of other places
* We could use mapType for substitution. (Check that we get
good code!)
* Some (but not yet all) clients of substitution can now
save time by using shallowTyCoVarsOfTypes
* All calls to tyCoVarsOfTypes should be inspected; most of
them should be shallow. Maybe.
* Currently shallowTyCoVarsOfTypes still returns
unification variables, but not CoVarHoles.
Reason: we need to return unification variables
in some of the calls in TcSimplify, eg when promoting.
* We should do the same thing for tyCoFVsOfTypes, which is
currently unchanged.
* tyCoFVsOfTypes returns CoVarHoles, because of the
use in TcSimplify.mkResidualConstraints. See
Note [Emitting the residual implication in simplifyInfer]
* #17509 talks about "relevant" variables too.
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After c846618ae0 we don't have accurate CafInfos for Ids in the current
module and we're free to introduce new CAFFY or non-CAFFY bindings or
change CafInfos of existing binders; so no we no longer need to
maintain CafInfos in Core or STG passes.
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In #17703 (a follow-up of !2192), we established that contrary to my
belief, type constraints arising from existentials in code like
```hs
data Ex where Ex :: a -> Ex
f _ | let x = Ex @Int 15 = case x of Ex -> ...
```
are in fact useful.
This commit makes a number of refactorings and improvements to comments,
but fundamentally changes `addCoreCt.core_expr` to record the type
constraint `a ~ Int` in addition to `x ~ Ex @a y` and `y ~ 15`.
Fixes #17703.
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The driver code is some of the nastiest in GHC, and I am worried about
being able to untangle all the tech debt. In `HscMain` we have a number
of helpers which are either not-used or little used. I delete them so we
can reduce cognative load, distilling the essential complexity away from
the cruft.
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I found the old control flow a bit hard to follow; I rewrote it to first
decide whether to desugar, and then use that choice when computing
whether to simplify / what sort of interface file to write.
I hope eventually we will always write post-tc interface files, which
will make the logic of this function even simpler, and continue the
thrust of this refactor.
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Other variant was removed in ac1a379363618a6f2f17fff65ce9129164b6ef30
but docs were no changed.
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This patch fixes #17566 by refactoring the way we decide the final
identity of the tyvars in the TyCons of a possibly-recursive nest
of type and class decls, possibly with associated types.
It's all laid out in
Note [Swizzling the tyvars before generaliseTcTyCon]
Main changes:
* We have to generalise each decl (with its associated types)
all at once: TcTyClsDecls.generaliseTyClDecl
* The main new work is done in TcTyClsDecls.swizzleTcTyConBndrs
* The mysterious TcHsSyn.zonkRecTyVarBndrs dies altogether
Other smaller things:
* A little refactoring, moving bindTyClTyVars from tcTyClDecl1
to tcDataDefn, tcSynRhs, etc. Clearer, reduces the number of
parameters
* Reduce the amount of swizzling required.
Specifically, bindExplicitTKBndrs_Q_Tv doesn't need
to clone a new Name for the TyVarTv, and not
cloning means that in the vasly common case,
swizzleTyConBndrs is a no-op
In detail:
Rename newTyVarTyVar --> cloneTyVarTyVar
Add newTyVarTyTyVar that doesn't clone
Use the non-cloning newTyVarTyVar in
bindExplicitTKBndrs_Q_Tv
Rename newFlexiKindedTyVarTyVar
--> cloneFlexiKindedTyVarTyVar
* Define new utility function and use it
HsDecls.familyDeclName ::
FamilyDecl (GhcPass p) -> IdP (GhcPass p)
Updates haddock submodule.
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In particular, show their kinds.
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This patch avoids skolemiseUnboundMetaTyVar making
up a fresh Name when it doesn't need to.
See Note [Skolemising and identity]
Improves error messsages for partial type signatures.
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(Guided by the profiler output)
- Add a few bang patterns, INLINABLE annotations, and a seqList in a few
places in Cmm and STG parts.
- Do not add external variables as dependencies in STG dependency
analysis (GHC.Stg.DepAnal).
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This patch removes all CafInfo predictions and various hacks to preserve
predicted CafInfos from the compiler and assigns final CafInfos to
interface Ids after code generation. SRT analysis is extended to support
static data, and Cmm generator is modified to allow generating
static_link fields after SRT analysis.
This also fixes `-fcatch-bottoms`, which introduces error calls in case
expressions in CorePrep, which runs *after* CoreTidy (which is where we
decide on CafInfos) and turns previously non-CAFFY things into CAFFY.
Fixes #17648
Fixes #9718
Evaluation
==========
NoFib
-----
Boot with: `make boot mode=fast`
Run: `make mode=fast EXTRA_RUNTEST_OPTS="-cachegrind" NoFibRuns=1`
--------------------------------------------------------------------------------
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% -0.5%
VSM -0.0% 0.0% -0.0% -0.0% -0.0%
anna -0.1% 0.0% -0.0% -0.0% -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% -0.0% -0.0% -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% -0.0% -0.0%
cacheprof -0.0% 0.0% -0.0% -0.0% -0.0%
calendar -0.0% 0.0% -0.0% -0.0% -0.0%
cichelli -0.0% 0.0% -0.0% -0.0% -0.0%
circsim -0.0% 0.0% -0.0% -0.0% -0.0%
clausify -0.0% 0.0% -0.0% -0.0% -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% -0.0% -0.0% -0.0%
cryptarithm1 -0.0% 0.0% -0.0% -0.0% -0.0%
cryptarithm2 -0.0% 0.0% -0.0% -0.0% -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% -0.0% -0.0% -0.0%
eliza -0.0% 0.0% -0.0% -0.0% -0.0%
event -0.0% 0.0% -0.0% -0.0% -0.0%
exact-reals -0.0% 0.0% -0.0% -0.0% -0.0%
exp3_8 -0.0% 0.0% -0.0% -0.0% -0.0%
expert -0.0% 0.0% -0.0% -0.0% -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 -0.1% 0.0% -0.0% -0.0% -0.0%
fulsom -0.0% 0.0% -0.0% -0.0% -0.0%
gamteb -0.0% 0.0% -0.0% -0.0% -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% -0.0% -0.0% -0.0%
hpg -0.1% 0.0% -0.0% -0.0% -0.0%
ida -0.0% 0.0% -0.0% -0.0% -0.0%
infer -0.0% 0.0% -0.0% -0.0% -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% -0.0% -0.0% -0.0%
lambda -0.0% 0.0% -0.0% -0.0% -0.0%
last-piece -0.0% 0.0% -0.0% -0.0% -0.0%
lcss -0.0% 0.0% -0.0% -0.0% -0.0%
life -0.0% 0.0% -0.0% -0.0% -0.0%
lift -0.0% 0.0% -0.0% -0.0% -0.0%
linear -0.1% 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% -0.0% -0.0% -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% -0.0% -0.0% -0.0%
mkhprog -0.0% 0.0% -0.0% -0.0% -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% -0.0% -0.0% -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 -0.1% 0.0% -0.0% -0.0% -0.0%
parstof -0.1% 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% -0.0% -0.0% -0.0%
pretty -0.0% 0.0% -0.3% -0.4% -0.4%
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% -0.0% -0.0% -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% -0.0% -0.0% -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% -0.3% -0.5% -0.4%
sched -0.0% 0.0% -0.0% -0.0% -0.0%
scs -0.0% 0.0% -0.0% -0.0% -0.0%
simple -0.1% 0.0% -0.0% -0.0% -0.0%
solid -0.0% 0.0% -0.0% -0.0% -0.0%
sorting -0.0% 0.0% -0.0% -0.0% -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% -0.0% -0.0% -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 -0.1% 0.0% -0.3% -0.5% -0.5%
Max -0.0% 0.0% -0.0% -0.0% -0.0%
Geometric Mean -0.0% -0.0% -0.0% -0.0% -0.0%
--------------------------------------------------------------------------------
Program Size Allocs Instrs Reads Writes
--------------------------------------------------------------------------------
circsim -0.1% 0.0% -0.0% -0.0% -0.0%
constraints -0.0% 0.0% -0.0% -0.0% -0.0%
fibheaps -0.0% 0.0% -0.0% -0.0% -0.0%
gc_bench -0.0% 0.0% -0.0% -0.0% -0.0%
hash -0.0% 0.0% -0.0% -0.0% -0.0%
lcss -0.0% 0.0% -0.0% -0.0% -0.0%
power -0.0% 0.0% -0.0% -0.0% -0.0%
spellcheck -0.0% 0.0% -0.0% -0.0% -0.0%
--------------------------------------------------------------------------------
Min -0.1% 0.0% -0.0% -0.0% -0.0%
Max -0.0% 0.0% -0.0% -0.0% -0.0%
Geometric Mean -0.0% +0.0% -0.0% -0.0% -0.0%
Manual inspection of programs in testsuite/tests/programs
---------------------------------------------------------
I built these programs with a bunch of dump flags and `-O` and compared
STG, Cmm, and Asm dumps and file sizes.
(Below the numbers in parenthesis show number of modules in the program)
These programs have identical compiler (same .hi and .o sizes, STG, and
Cmm and Asm dumps):
- Queens (1), andre_monad (1), cholewo-eval (2), cvh_unboxing (3),
andy_cherry (7), fun_insts (1), hs-boot (4), fast2haskell (2),
jl_defaults (1), jq_readsPrec (1), jules_xref (1), jtod_circint (4),
jules_xref2 (1), lennart_range (1), lex (1), life_space_leak (1),
bargon-mangler-bug (7), record_upd (1), rittri (1), sanders_array (1),
strict_anns (1), thurston-module-arith (2), okeefe_neural (1),
joao-circular (6), 10queens (1)
Programs with different compiler outputs:
- jl_defaults (1): For some reason GHC HEAD marks a lot of top-level
`[Int]` closures as CAFFY for no reason. With this patch we no longer
make them CAFFY and generate less SRT entries. For some reason Main.o
is slightly larger with this patch (1.3%) and the executable sizes are
the same. (I'd expect both to be smaller)
- launchbury (1): Same as jl_defaults: top-level `[Int]` closures marked
as CAFFY for no reason. Similarly `Main.o` is 1.4% larger but the
executable sizes are the same.
- galois_raytrace (13): Differences are in the Parse module. There are a
lot, but some of the changes are caused by the fact that for some
reason (I think a bug) GHC HEAD marks the dictionary for `Functor
Identity` as CAFFY. Parse.o is 0.4% larger, the executable size is the
same.
- north_array: We now generate less SRT entries because some of array
primops used in this program like `NewArrayOp` get eliminated during
Stg-to-Cmm and turn some CAFFY things into non-CAFFY. Main.o gets 24%
larger (9224 bytes from 9000 bytes), executable sizes are the same.
- seward-space-leak: Difference in this program is better shown by this
smaller example:
module Lib where
data CDS
= Case [CDS] [(Int, CDS)]
| Call CDS CDS
instance Eq CDS where
Case sels1 rets1 == Case sels2 rets2 =
sels1 == sels2 && rets1 == rets2
Call a1 b1 == Call a2 b2 =
a1 == a2 && b1 == b2
_ == _ =
False
In this program GHC HEAD builds a new SRT for the recursive group of
`(==)`, `(/=)` and the dictionary closure. Then `/=` points to `==`
in its SRT field, and `==` uses the SRT object as its SRT. With this
patch we use the closure for `/=` as the SRT and add `==` there. Then
`/=` gets an empty SRT field and `==` points to `/=` in its SRT
field.
This change looks fine to me.
Main.o gets 0.07% larger, executable sizes are identical.
head.hackage
------------
head.hackage's CI script builds 428 packages from Hackage using this
patch with no failures.
Compiler performance
--------------------
The compiler perf tests report that the compiler allocates slightly more
(worst case observed so far is 4%). However most programs in the test
suite are small, single file programs. To benchmark compiler performance
on something more realistic I build Cabal (the library, 236 modules)
with different optimisation levels. For the "max residency" row I run
GHC with `+RTS -s -A100k -i0 -h` for more accurate numbers. Other rows
are generated with just `-s`. (This is because `-i0` causes running GC
much more frequently and as a result "bytes copied" gets inflated by
more than 25x in some cases)
* -O0
| | GHC HEAD | This MR | Diff |
| --------------- | -------------- | -------------- | ------ |
| Bytes allocated | 54,413,350,872 | 54,701,099,464 | +0.52% |
| Bytes copied | 4,926,037,184 | 4,990,638,760 | +1.31% |
| Max residency | 421,225,624 | 424,324,264 | +0.73% |
* -O1
| | GHC HEAD | This MR | Diff |
| --------------- | --------------- | --------------- | ------ |
| Bytes allocated | 245,849,209,992 | 246,562,088,672 | +0.28% |
| Bytes copied | 26,943,452,560 | 27,089,972,296 | +0.54% |
| Max residency | 982,643,440 | 991,663,432 | +0.91% |
* -O2
| | GHC HEAD | This MR | Diff |
| --------------- | --------------- | --------------- | ------ |
| Bytes allocated | 291,044,511,408 | 291,863,910,912 | +0.28% |
| Bytes copied | 37,044,237,616 | 36,121,690,472 | -2.49% |
| Max residency | 1,071,600,328 | 1,086,396,256 | +1.38% |
Extra compiler allocations
--------------------------
Runtime allocations of programs are as reported above (NoFib section).
The compiler now allocates more than before. Main source of allocation
in this patch compared to base commit is the new SRT algorithm
(GHC.Cmm.Info.Build). Below is some of the extra work we do with this
patch, numbers generated by profiled stage 2 compiler when building a
pathological case (the test 'ManyConstructors') with '-O2':
- We now sort the final STG for a module, which means traversing the
entire program, generating free variable set for each top-level
binding, doing SCC analysis, and re-ordering the program. In
ManyConstructors this step allocates 97,889,952 bytes.
- We now do SRT analysis on static data, which in a program like
ManyConstructors causes analysing 10,000 bindings that we would
previously just skip. This step allocates 70,898,352 bytes.
- We now maintain an SRT map for the entire module as we compile Cmm
groups:
data ModuleSRTInfo = ModuleSRTInfo
{ ...
, moduleSRTMap :: SRTMap
}
(SRTMap is just a strict Map from the 'containers' library)
This map gets an entry for most bindings in a module (exceptions are
THUNKs and CAFFY static functions). For ManyConstructors this map
gets 50015 entries.
- Once we're done with code generation we generate a NameSet from SRTMap
for the non-CAFFY names in the current module. This set gets the same
number of entries as the SRTMap.
- Finally we update CafInfos in ModDetails for the non-CAFFY Ids, using
the NameSet generated in the previous step. This usually does the
least amount of allocation among the work listed here.
Only place with this patch where we do less work in the CAF analysis in
the tidying pass (CoreTidy). However that doesn't save us much, as the
pass still needs to traverse the whole program and update IdInfos for
other reasons. Only thing we don't here do is the `hasCafRefs` pass over
the RHS of bindings, which is a stateless pass that returns a boolean
value, so it doesn't allocate much.
(Metric changes blow are all increased allocations)
Metric changes
--------------
Metric Increase:
ManyAlternatives
ManyConstructors
T13035
T14683
T1969
T9961
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Replacing it with `newSysName`. Fixes #17061.
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The package terminology is a bit of a mess. Cabal packages contain
components. Instances of these components when built with some
flags/options/dependencies are called units. Units are registered into
package databases and their metadata are called PackageConfig.
GHC only knows about package databases containing units. It is a sad
mismatch not fixed by this patch (we would have to rename parameters
such as `package-id <unit-id>` which would affect users).
This patch however fixes the following internal names:
- Renames PackageConfig into UnitInfo.
- Rename systemPackageConfig into globalPackageDatabase[Path]
- Rename PkgConfXX into PkgDbXX
- Rename pkgIdMap into unitIdMap
- Rename ModuleToPkgDbAll into ModuleNameProvidersMap
- Rename lookupPackage into lookupUnit
- Add comments on DynFlags package related fields
It also introduces a new `PackageDatabase` datatype instead of
explicitly passing the following tuple: `(FilePath,[PackageConfig])`.
The `pkgDatabase` field in `DynFlags` now contains the unit info for
each unit of each package database exactly as they have been read from
disk. Previously the command-line flag `-distrust-all-packages` would
modify these unit info. Now this flag only affects the "dynamic"
consolidated package state found in `pkgState` field. It makes sense
because `initPackages` could be called first with this
`distrust-all-packages` flag set and then again (using ghc-api) without
and it should work (package databases are not read again from disk when
`initPackages` is called the second time).
Bump haddock submodule
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interpretPackageEnv modifies the flags by reading the dreaded package
environments. It is much less surprising to call it from
`setSessionDynFlags` instead of reading package environments as a
side-effect of `initPackages`.
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incomplete-uni-patterns and incomplete-record-updates will be in -Wall at a
future date, so prepare for that by disabling those warnings on files that
trigger them.
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Richard points out in #17688 that we use `splitLHsForAllTy` and
`splitLHsSigmaTy` in places that we ought to be using the
corresponding `-Invis` variants instead, identifying two bugs
that are caused by this oversight:
* Certain TH-quoted type signatures, such as those that appear in
quoted `SPECIALISE` pragmas, silently turn visible `forall`s into
invisible `forall`s.
* When quoted, the type `forall a -> (a ~ a) => a` will turn into
`forall a -> a` due to a bug in `DsMeta.repForall` that drops
contexts that follow visible `forall`s.
These are both ultimately caused by the fact that `splitLHsForAllTy`
and `splitLHsSigmaTy` split apart visible `forall`s in addition to
invisible ones. This patch cleans things up:
* We now use `splitLHsForAllTyInvis` and `splitLHsSigmaTyInvis`
throughout the codebase. Relatedly, the `splitLHsForAllTy` and
`splitLHsSigmaTy` have been removed, as they are easy to misuse.
* `DsMeta.repForall` now only handles invisible `forall`s to reduce
the chance for confusion with visible `forall`s, which need to be
handled differently. I also renamed it from `repForall` to
`repForallT` to emphasize that its distinguishing characteristic
is the fact that it desugars down to `L.H.TH.Syntax.ForallT`.
Fixes #17688.
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Previously, `hsScopedTvs` (and its cousin `hsWcScopedTvs`) pretended
that visible dependent quantification could not possibly happen at
the term level, and cemented that assumption with an `ASSERT`:
```hs
hsScopedTvs (HsForAllTy { hst_fvf = vis_flag, ... }) =
ASSERT( vis_flag == ForallInvis )
...
```
It turns out that this assumption is wrong. You can end up tripping
this `ASSERT` if you stick it to the man and write a type for a term
that uses visible dependent quantification anyway, like in this
example:
```hs
{-# LANGUAGE ScopedTypeVariables #-}
x :: forall a -> a -> a
x = x
```
That won't typecheck, but that's not the point. Before the
typechecker has a chance to reject this, the renamer will try
to use `hsScopedTvs` to bring `a` into scope over the body of `x`,
since `a` is quantified by a `forall`. This, in turn, causes the
`ASSERT` to fail. Bummer.
Instead of walking on this dangerous ground, this patch makes GHC
adopt a more hardline stance by pattern-matching directly on
`ForallInvis` in `hsScopedTvs`:
```hs
hsScopedTvs (HsForAllTy { hst_fvf = ForallInvis, ... }) = ...
```
Now `a` will not be brought over the body of `x` at all (which is how
it should be), there's no chance of the `ASSERT` failing anymore (as
it's gone), and best of all, the behavior of `hsScopedTvs` does not
change. Everyone wins!
Fixes #17687.
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`DsMeta.rep_sig` used to skip over `FixSig` entirely, which had the
effect of causing local fixity declarations to be dropped when quoted
in Template Haskell. But there is no good reason for this state of
affairs, as the code in `DsMeta.repFixD` (which handles top-level
fixity declarations) handles local fixity declarations just fine.
This patch factors out the necessary parts of `repFixD` so that they
can be used in `rep_sig` as well.
There was one minor complication: the fixity signatures for class
methods in each `HsGroup` were stored both in `FixSig`s _and_ the
list of `LFixitySig`s for top-level fixity signatures, so I needed
to take action to prevent fixity signatures for class methods being
converted to `Dec`s twice. I tweaked `RnSource.add` to avoid putting
these fixity signatures in two places and added
`Note [Top-level fixity signatures in an HsGroup]` in `GHC.Hs.Decls`
to explain the new design.
Fixes #17608. Bumps the Haddock submodule.
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In https://gitlab.haskell.org/ghc/ghc/merge_requests/2192#note_246551
Simon convinced me that ignoring type variables existentially bound by
data constructors have to be the same way as value binders.
Sadly I couldn't think of a regression test, but I'm confident that this
change strictly improves on the status quo.
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We used to check `GrdVec`s arising from multiple clauses and guards in
isolation. That resulted in a split between `pmCheck` and
`pmCheckGuards`, the implementations of which were similar, but subtly
different in detail. Also the throttling mechanism described in
`Note [Countering exponential blowup]` ultimately got quite complicated
because it had to cater for both checking functions.
This patch realises that pattern match checking doesn't just consider
single guarded RHSs, but that it's always a whole set of clauses, each
of which can have multiple guarded RHSs in turn. We do so by
translating a list of `Match`es to a `GrdTree`:
```haskell
data GrdTree
= Rhs !RhsInfo
| Guard !PmGrd !GrdTree -- captures lef-to-right match semantics
| Sequence !GrdTree !GrdTree -- captures top-to-bottom match semantics
| Empty -- For -XEmptyCase, neutral element of Sequence
```
Then we have a function `checkGrdTree` that matches a given `GrdTree`
against an incoming set of values, represented by `Deltas`:
```haskell
checkGrdTree :: GrdTree -> Deltas -> CheckResult
...
```
Throttling is isolated to the `Sequence` case and becomes as easy as one
would expect: When the union of uncovered values becomes too big, just
return the original incoming `Deltas` instead (which is always a
superset of the union, thus a sound approximation).
The returned `CheckResult` contains two things:
1. The set of values that were not covered by any of the clauses, for
exhaustivity warnings.
2. The `AnnotatedTree` that enriches the syntactic structure of the
input program with divergence and inaccessibility information.
This is `AnnotatedTree`:
```haskell
data AnnotatedTree
= AccessibleRhs !RhsInfo
| InaccessibleRhs !RhsInfo
| MayDiverge !AnnotatedTree
| SequenceAnn !AnnotatedTree !AnnotatedTree
| EmptyAnn
```
Crucially, `MayDiverge` asserts that the tree may force diverging
values, so not all of its wrapped clauses can be redundant.
While the set of uncovered values can be used to generate the missing
equations for warning messages, redundant and proper inaccessible
equations can be extracted from `AnnotatedTree` by
`redundantAndInaccessibleRhss`.
For this to work properly, the interface to the Oracle had to change.
There's only `addPmCts` now, which takes a bag of `PmCt`s. There's a
whole bunch of `PmCt` variants to replace the different oracle functions
from before.
The new `AnnotatedTree` structure allows for more accurate warning
reporting (as evidenced by a number of changes spread throughout GHC's
code base), thus we fix #17465.
Fixes #17646 on the go.
Metric Decrease:
T11822
T9233
PmSeriesS
haddock.compiler
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Closes #17659.
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It was deprecated in 2012 with 46258b40
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