[Git][ghc/ghc][master] Remove SpecConstrAnnotation (#13681)
Marge Bot
gitlab at gitlab.haskell.org
Tue May 5 07:23:42 UTC 2020
Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC
Commits:
7bc3a65b by Sylvain Henry at 2020-05-05T03:23:31-04:00
Remove SpecConstrAnnotation (#13681)
This has been deprecated since 2013. Use GHC.Types.SPEC instead.
Make GHC.Exts "not-home" for haddock
Metric Decrease:
haddock.base
- - - - -
5 changed files:
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Driver/Session.hs
- libraries/base/GHC/Exts.hs
- testsuite/tests/simplCore/should_compile/T5550.hs
- testsuite/tests/simplCore/should_compile/T7944.hs
Changes:
=====================================
compiler/GHC/Core/Opt/SpecConstr.hs
=====================================
@@ -1,23 +1,18 @@
{-
-ToDo [Oct 2013]
-~~~~~~~~~~~~~~~
-1. Nuke ForceSpecConstr for good (it is subsumed by GHC.Types.SPEC in ghc-prim)
-2. Nuke NoSpecConstr
-
(c) The GRASP/AQUA Project, Glasgow University, 1992-1998
-\section[SpecConstr]{Specialise over constructors}
-}
{-# LANGUAGE CPP #-}
{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
-module GHC.Core.Opt.SpecConstr(
- specConstrProgram,
- SpecConstrAnnotation(..)
- ) where
+-- | Specialise over constructors
+module GHC.Core.Opt.SpecConstr
+ ( specConstrProgram
+ )
+where
#include "HsVersions.h"
@@ -49,7 +44,6 @@ import GHC.Driver.Session ( DynFlags(..), GeneralFlag( Opt_SpecConstrKeen )
import GHC.Data.Maybe ( orElse, catMaybes, isJust, isNothing )
import GHC.Types.Demand
import GHC.Types.Cpr
-import GHC.Serialized ( deserializeWithData )
import GHC.Utils.Misc
import GHC.Data.Pair
import GHC.Types.Unique.Supply
@@ -61,8 +55,6 @@ import Control.Monad ( zipWithM )
import Data.List
import GHC.Builtin.Names ( specTyConName )
import GHC.Unit.Module
-import GHC.Core.TyCon ( TyCon )
-import GHC.Exts( SpecConstrAnnotation(..) )
import Data.Ord( comparing )
{-
@@ -454,32 +446,19 @@ With stream fusion and in other similar cases, we want to fully
specialise some (but not necessarily all!) loops regardless of their
size and the number of specialisations.
-We allow a library to do this, in one of two ways (one which is
-deprecated):
-
- 1) Add a parameter of type GHC.Types.SPEC (from ghc-prim) to the loop body.
-
- 2) (Deprecated) Annotate a type with ForceSpecConstr from GHC.Exts,
- and then add *that* type as a parameter to the loop body
+We allow a library to force the specialisation by adding a parameter of type
+GHC.Types.SPEC (from ghc-prim) to the loop body.
-The reason #2 is deprecated is because it requires GHCi, which isn't
-available for things like a cross compiler using stage1.
+ Historical note: in the past any datatype could be used in place of
+ GHC.Types.SPEC as long as it was annotated with GHC.Exts.ForceSpecConstr. It
+ has been deprecated because it required GHCi, which isn't available for
+ things like a cross compiler using stage1.
Here's a (simplified) example from the `vector` package. You may bring
the special 'force specialization' type into scope by saying:
import GHC.Types (SPEC(..))
-or by defining your own type (again, deprecated):
-
- data SPEC = SPEC | SPEC2
- {-# ANN type SPEC ForceSpecConstr #-}
-
-(Note this is the exact same definition of GHC.Types.SPEC, just
-without the annotation.)
-
-After that, you say:
-
foldl :: (a -> b -> a) -> a -> Stream b -> a
{-# INLINE foldl #-}
foldl f z (Stream step s _) = foldl_loop SPEC z s
@@ -501,7 +480,7 @@ foldl_loop. Note that
This is all quite ugly; we ought to come up with a better design.
-ForceSpecConstr arguments are spotted in scExpr' and scTopBinds which then set
+SPEC arguments are spotted in scExpr' and scTopBinds which then set
sc_force to True when calling specLoop. This flag does four things:
* Ignore specConstrThreshold, to specialise functions of arbitrary size
@@ -544,8 +523,8 @@ What alternatives did I consider?
user (e.g., the accumulator here) but we still want to specialise as
much as possible.
-Alternatives to ForceSpecConstr
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Alternatives to SPEC
+~~~~~~~~~~~~~~~~~~~~
Instead of giving the loop an extra argument of type SPEC, we
also considered *wrapping* arguments in SPEC, thus
data SPEC a = SPEC a | SPEC2
@@ -569,13 +548,13 @@ this doesn't look like a specialisable call.
Note [Limit recursive specialisation]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-It is possible for ForceSpecConstr to cause an infinite loop of specialisation.
+It is possible for SPEC to cause an infinite loop of specialisation.
Because there is no limit on the number of specialisations, a recursive call with
a recursive constructor as an argument (for example, list cons) will generate
a specialisation for that constructor. If the resulting specialisation also
contains a recursive call with the constructor, this could proceed indefinitely.
-For example, if ForceSpecConstr is on:
+For example, if SPEC is on:
loop :: [Int] -> [Int] -> [Int]
loop z [] = z
loop z (x:xs) = loop (x:z) xs
@@ -605,16 +584,6 @@ more than N times (controlled by -fspec-constr-recursive=N) we check
See #5550. Also #13623, where this test had become over-aggressive,
and we lost a wonderful specialisation that we really wanted!
-Note [NoSpecConstr]
-~~~~~~~~~~~~~~~~~~~
-The ignoreDataCon stuff allows you to say
- {-# ANN type T NoSpecConstr #-}
-to mean "don't specialise on arguments of this type". It was added
-before we had ForceSpecConstr. Lacking ForceSpecConstr we specialised
-regardless of size; and then we needed a way to turn that *off*. Now
-that we have ForceSpecConstr, this NoSpecConstr is probably redundant.
-(Used only for PArray, TODO: remove?)
-
-----------------------------------------------------
Stuff not yet handled
-----------------------------------------------------
@@ -702,11 +671,10 @@ specConstrProgram guts
= do
dflags <- getDynFlags
us <- getUniqueSupplyM
- (_, annos) <- getFirstAnnotations deserializeWithData guts
this_mod <- getModule
let binds' = reverse $ fst $ initUs us $ do
-- Note [Top-level recursive groups]
- (env, binds) <- goEnv (initScEnv dflags this_mod annos)
+ (env, binds) <- goEnv (initScEnv dflags this_mod)
(mg_binds guts)
-- binds is identical to (mg_binds guts), except that the
-- binders on the LHS have been replaced by extendBndr
@@ -821,7 +789,7 @@ data ScEnv = SCE { sc_dflags :: DynFlags,
-- See Note [Avoiding exponential blowup]
sc_recursive :: Int, -- Max # of specialisations over recursive type.
- -- Stops ForceSpecConstr from diverging.
+ -- Stops SPEC from diverging.
sc_keen :: Bool, -- Specialise on arguments that are known
-- constructors, even if they are not
@@ -838,15 +806,13 @@ data ScEnv = SCE { sc_dflags :: DynFlags,
-- Binds interesting non-top-level variables
-- Domain is OutVars (*after* applying the substitution)
- sc_vals :: ValueEnv,
+ sc_vals :: ValueEnv
-- Domain is OutIds (*after* applying the substitution)
-- Used even for top-level bindings (but not imported ones)
-- The range of the ValueEnv is *work-free* values
-- such as (\x. blah), or (Just v)
-- but NOT (Just (expensive v))
-- See Note [Work-free values only in environment]
-
- sc_annotations :: UniqFM SpecConstrAnnotation
}
---------------------
@@ -863,8 +829,8 @@ instance Outputable Value where
ppr LambdaVal = text "<Lambda>"
---------------------
-initScEnv :: DynFlags -> Module -> UniqFM SpecConstrAnnotation -> ScEnv
-initScEnv dflags this_mod anns
+initScEnv :: DynFlags -> Module -> ScEnv
+initScEnv dflags this_mod
= SCE { sc_dflags = dflags,
sc_module = this_mod,
sc_size = specConstrThreshold dflags,
@@ -874,8 +840,7 @@ initScEnv dflags this_mod anns
sc_force = False,
sc_subst = emptySubst,
sc_how_bound = emptyVarEnv,
- sc_vals = emptyVarEnv,
- sc_annotations = anns }
+ sc_vals = emptyVarEnv }
data HowBound = RecFun -- These are the recursive functions for which
-- we seek interesting call patterns
@@ -1000,21 +965,7 @@ decreaseSpecCount env n_specs
---------------------------------------------------
-- See Note [Forcing specialisation]
-ignoreType :: ScEnv -> Type -> Bool
-ignoreDataCon :: ScEnv -> DataCon -> Bool
forceSpecBndr :: ScEnv -> Var -> Bool
-
-ignoreDataCon env dc = ignoreTyCon env (dataConTyCon dc)
-
-ignoreType env ty
- = case tyConAppTyCon_maybe ty of
- Just tycon -> ignoreTyCon env tycon
- _ -> False
-
-ignoreTyCon :: ScEnv -> TyCon -> Bool
-ignoreTyCon env tycon
- = lookupUFM (sc_annotations env) tycon == Just NoSpecConstr
-
forceSpecBndr env var = forceSpecFunTy env . snd . splitForAllTys . varType $ var
forceSpecFunTy :: ScEnv -> Type -> Bool
@@ -1028,7 +979,6 @@ forceSpecArgTy env ty
| Just (tycon, tys) <- splitTyConApp_maybe ty
, tycon /= funTyCon
= tyConName tycon == specTyConName
- || lookupUFM (sc_annotations env) tycon == Just ForceSpecConstr
|| any (forceSpecArgTy env) tys
forceSpecArgTy _ _ = False
@@ -1898,9 +1848,9 @@ by trim_pats.
of specialisations for a given function to N.
* -fno-spec-constr-count sets the sc_count field to Nothing,
- which switches of the limit.
+ which switches off the limit.
-* The ghastly ForceSpecConstr trick also switches of the limit
+* The ghastly SPEC trick also switches off the limit
for a particular function
* Otherwise we sort the patterns to choose the most general
@@ -2173,7 +2123,6 @@ argToPat env in_scope val_env (Case scrut _ _ [(_, _, rhs)]) arg_occ
-}
argToPat env in_scope val_env (Cast arg co) arg_occ
- | not (ignoreType env ty2)
= do { (interesting, arg') <- argToPat env in_scope val_env arg arg_occ
; if not interesting then
wildCardPat ty2
@@ -2204,7 +2153,6 @@ argToPat in_scope val_env arg arg_occ
-- NB: this *precedes* the Var case, so that we catch nullary constrs
argToPat env in_scope val_env arg arg_occ
| Just (ConVal (DataAlt dc) args) <- isValue val_env arg
- , not (ignoreDataCon env dc) -- See Note [NoSpecConstr]
, Just arg_occs <- mb_scrut dc
= do { let (ty_args, rest_args) = splitAtList (dataConUnivTyVars dc) args
; (_, args') <- argsToPats env in_scope val_env rest_args arg_occs
@@ -2225,11 +2173,10 @@ argToPat env in_scope val_env arg arg_occ
-- In that case it counts as "interesting"
argToPat env in_scope val_env (Var v) arg_occ
| sc_force env || case arg_occ of { UnkOcc -> False; _other -> True }, -- (a)
- is_value, -- (b)
+ is_value -- (b)
-- Ignoring sc_keen here to avoid gratuitously incurring Note [Reboxing]
-- So sc_keen focused just on f (I# x), where we have freshly-allocated
-- box that we can eliminate in the caller
- not (ignoreType env (varType v))
= return (True, Var v)
where
is_value
=====================================
compiler/GHC/Driver/Session.hs
=====================================
@@ -496,7 +496,7 @@ data DynFlags = DynFlags {
specConstrThreshold :: Maybe Int, -- ^ Threshold for SpecConstr
specConstrCount :: Maybe Int, -- ^ Max number of specialisations for any one function
specConstrRecursive :: Int, -- ^ Max number of specialisations for recursive types
- -- Not optional; otherwise ForceSpecConstr can diverge.
+ -- Not optional; otherwise SPEC can diverge.
binBlobThreshold :: Word, -- ^ Binary literals (e.g. strings) whose size is above
-- this threshold will be dumped in a binary file
-- by the assembler code generator (0 to disable)
=====================================
libraries/base/GHC/Exts.hs
=====================================
@@ -2,6 +2,8 @@
{-# LANGUAGE MagicHash, UnboxedTuples, TypeFamilies, DeriveDataTypeable,
MultiParamTypeClasses, FlexibleInstances, NoImplicitPrelude #-}
+{-# OPTIONS_HADDOCK not-home #-}
+
-----------------------------------------------------------------------------
-- |
-- Module : GHC.Exts
@@ -83,9 +85,6 @@ module GHC.Exts
-- * Event logging
traceEvent,
- -- * SpecConstr annotations
- SpecConstrAnnotation(..),
-
-- * The call stack
currentCallStack,
@@ -111,7 +110,6 @@ import GHC.Stack
import qualified Data.Coerce
import Data.String
import Data.OldList
-import Data.Data
import Data.Ord
import Data.Version ( Version(..), makeVersion )
import qualified Debug.Trace
@@ -159,25 +157,6 @@ traceEvent = Debug.Trace.traceEventIO
{-# DEPRECATED traceEvent "Use 'Debug.Trace.traceEvent' or 'Debug.Trace.traceEventIO'" #-} -- deprecated in 7.4
-{- **********************************************************************
-* *
-* SpecConstr annotation *
-* *
-********************************************************************** -}
-
--- Annotating a type with NoSpecConstr will make SpecConstr
--- not specialise for arguments of that type.
-
--- This data type is defined here, rather than in the SpecConstr module
--- itself, so that importing it doesn't force stupidly linking the
--- entire ghc package at runtime
-
-data SpecConstrAnnotation = NoSpecConstr | ForceSpecConstr
- deriving ( Data -- ^ @since 4.3.0.0
- , Eq -- ^ @since 4.3.0.0
- )
-
-
{- **********************************************************************
* *
* The IsList class *
=====================================
testsuite/tests/simplCore/should_compile/T5550.hs
=====================================
@@ -1,9 +1,6 @@
module T5550 where
-import GHC.Exts ( SpecConstrAnnotation(..) )
-
-data SPEC = SPEC | SPEC2
-{-# ANN type SPEC ForceSpecConstr #-}
+import GHC.Types
loop :: SPEC -> [Int] -> [Int] -> [Int]
loop SPEC z [] = z
=====================================
testsuite/tests/simplCore/should_compile/T7944.hs
=====================================
@@ -1,10 +1,6 @@
module T7944 where
-import GHC.Exts
-
--- Force specialisation of "go"
-data SPEC = SPEC | SPEC2
-{-# ANN type SPEC ForceSpecConstr #-}
+import GHC.Types
-- This is more or less just an ordinary fold
go :: SPEC -> [a] -> IntMap a -> IntMap a
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/7bc3a65b467c4286377b9bded277d5a2f69160b3
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/7bc3a65b467c4286377b9bded277d5a2f69160b3
You're receiving this email because of your account on gitlab.haskell.org.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/ghc-commits/attachments/20200505/4c6ded08/attachment-0001.html>
More information about the ghc-commits
mailing list