Commit b8875f2f authored by simonm's avatar simonm
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[project @ 1996-03-26 17:10:41 by simonm]

Split Specialise.lhs into
To reduce heap-size requirements for compiling this module.
parent f6ca98ca
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% (c) The GRASP/AQUA Project, Glasgow University, 1993-1995
\section[SpecMonad]{Monad for the Specialiser}
#include "HsVersions.h"
module SpecMonad where
import PlainCore
import SpecTyFuns
import Outputable -- ToDo: these may be removable...
import Pretty
import AbsUniType
import Bag
import CmdLineOpts ( GlobalSwitch(..) )
import CoreLift ( mkLiftedId, liftExpr, bindUnlift, applyBindUnlifts )
import IdEnv
import Id
import IdInfo
import InstEnv ( lookupClassInstAtSimpleType )
import Maybes ( catMaybes, firstJust, maybeToBool, Maybe(..) )
import TyVarEnv -- ( growTyVarEnvList, nullTyVarEnv, TyVarEnv, TypeEnv(..) )
import Util
import UniqSet
import SplitUniq
infixr 9 `thenSM`
%* *
\subsection[cloning-binders]{The Specialising IdEnv and CloneInfo}
%* *
@SpecIdEnv@ maps old Ids to their new "clone". There are three cases:
1) (NoLift CoLitAtom l) : an Id which is bound to a literal
2) (NoLift CoLitAtom l) : an Id bound to a "new" Id
The new Id is a possibly-type-specialised clone of the original
3) Lifted lifted_id unlifted_id :
This indicates that the original Id has been specialised to an
unboxed value which must be lifted (see "Unboxed bindings" above)
@unlifted_id@ is the unboxed clone of the original Id
@lifted_id@ is a *lifted* version of the original Id
When you lookup Ids which are Lifted, you have to insert a case
expression to un-lift the value (done with @bindUnlift@)
You also have to insert a case to lift the value in the binding
(done with @liftExpr@)
type SpecIdEnv = IdEnv CloneInfo
data CloneInfo
= NoLift PlainCoreAtom -- refers to cloned id or literal
| Lifted Id -- lifted, cloned id
Id -- unlifted, cloned id
%* *
\subsection[monad-Specialise]{Monad used in specialisation}
%* *
Monad has:
inherited: control flags and
recordInst functions with flags cached
environment mapping tyvars to types
environment mapping Ids to Atoms
threaded in and out: unique supply
type SpecM result
= (GlobalSwitch -> Bool)
-> TypeEnv
-> SpecIdEnv
-> SplitUniqSupply
-> result
initSM m sw_chker uniqs
= m sw_chker nullTyVarEnv nullIdEnv uniqs
returnSM :: a -> SpecM a
thenSM :: SpecM a -> (a -> SpecM b) -> SpecM b
fixSM :: (a -> SpecM a) -> SpecM a
thenSM m k sw_chkr tvenv idenv us
= case splitUniqSupply us of { (s1, s2) ->
case (m sw_chkr tvenv idenv s1) of { r ->
k r sw_chkr tvenv idenv s2 }}
returnSM r sw_chkr tvenv idenv us = r
fixSM k sw_chkr tvenv idenv us
= r
r = k r sw_chkr tvenv idenv us -- Recursive in r!
getSwitchCheckerSM sw_chkr tvenv idenv us = sw_chkr
The only interesting bit is figuring out the type of the SpecId!
newSpecIds :: [Id] -- The id of which to make a specialised version
-> [Maybe UniType] -- Specialise to these types
-> Int -- No of dicts to specialise
-> SpecM [Id]
newSpecIds new_ids maybe_tys dicts_to_ignore sw_chkr tvenv idenv us
= [ mkSpecId uniq id maybe_tys (spec_id_ty id) (selectIdInfoForSpecId id)
| (id,uniq) <- new_ids `zip` uniqs ]
uniqs = getSUniques (length new_ids) us
spec_id_ty id = specialiseTy (getIdUniType id) maybe_tys dicts_to_ignore
newTyVars :: Int -> SpecM [TyVar]
newTyVars n sw_chkr tvenv idenv us
= map mkPolySysTyVar uniqs
uniqs = getSUniques n us
@cloneLambdaOrCaseBinders@ and @cloneLetBinders@ take a bunch of
binders, and build ``clones'' for them. The clones differ from the
originals in three ways:
(a) they have a fresh unique
(b) they have the current type environment applied to their type
(c) for Let binders which have been specialised to unboxed values
the clone will have a lifted type
As well as returning the list of cloned @Id@s they also return a list of
@CloneInfo@s which the original binders should be bound to.
cloneLambdaOrCaseBinders :: [Id] -- Old binders
-> SpecM ([Id], [CloneInfo]) -- New ones
cloneLambdaOrCaseBinders old_ids sw_chkr tvenv idenv us
= let
uniqs = getSUniques (length old_ids) us
unzip (zipWith clone_it old_ids uniqs)
clone_it old_id uniq
= (new_id, NoLift (CoVarAtom new_id))
new_id = applyTypeEnvToId tvenv (mkIdWithNewUniq old_id uniq)
cloneLetBinders :: Bool -- Top level ?
-> Bool -- Recursice
-> [Id] -- Old binders
-> SpecM ([Id], [CloneInfo]) -- New ones
cloneLetBinders top_lev is_rec old_ids sw_chkr tvenv idenv us
= let
uniqs = getSUniques (2 * length old_ids) us
unzip (clone_them old_ids uniqs)
clone_them [] [] = []
clone_them (old_id:olds) (u1:u2:uniqs)
| top_lev
= (old_id,
NoLift (CoVarAtom old_id)) : clone_rest
-- Don't clone if it is a top-level thing. Why not?
-- (a) we don't want to change the uniques
-- on such things (see TopLevId in Id.lhs)
-- (b) we don't have to be paranoid about name capture
-- (c) the thing is polymorphic so no need to subst
| otherwise
= if (is_rec && isUnboxedDataType new_ty && not (isUnboxedDataType old_ty))
then (lifted_id,
Lifted lifted_id unlifted_id) : clone_rest
else (new_id,
NoLift (CoVarAtom new_id)) : clone_rest
clone_rest = clone_them olds uniqs
new_id = applyTypeEnvToId tvenv (mkIdWithNewUniq old_id u1)
new_ty = getIdUniType new_id
old_ty = getIdUniType old_id
(lifted_id, unlifted_id) = mkLiftedId new_id u2
cloneTyVarSM :: TyVar -> SpecM TyVar
cloneTyVarSM old_tyvar sw_chkr tvenv idenv us
= let
uniq = getSUnique us
cloneTyVar old_tyvar uniq -- new_tyvar
bindId :: Id -> CloneInfo -> SpecM thing -> SpecM thing
bindId id val specm sw_chkr tvenv idenv us
= specm sw_chkr tvenv (addOneToIdEnv idenv id val) us
bindIds :: [Id] -> [CloneInfo] -> SpecM thing -> SpecM thing
bindIds olds news specm sw_chkr tvenv idenv us
= specm sw_chkr tvenv (growIdEnvList idenv (zip olds news)) us
bindSpecIds :: [Id] -- Old
-> [(CloneInfo)] -- New
-> [[Maybe SpecInfo]] -- Corresponding specialisations
-- Each sub-list corresponds to a different type,
-- and contains one Maybe spec_info for each id
-> SpecM thing
-> SpecM thing
bindSpecIds olds clones spec_infos specm sw_chkr tvenv idenv us
= specm sw_chkr tvenv (growIdEnvList idenv old_to_clone) us
old_to_clone = mk_old_to_clone olds clones spec_infos
-- The important thing here is that we are *lazy* in spec_infos
mk_old_to_clone [] [] _ = []
mk_old_to_clone (old:rest_olds) (clone:rest_clones) spec_infos
= (old, add_spec_info clone) :
mk_old_to_clone rest_olds rest_clones spec_infos_rest
add_spec_info (NoLift (CoVarAtom new))
= NoLift (CoVarAtom (new `addIdSpecialisation`
(mkSpecEnv spec_infos_this_id)))
add_spec_info lifted
= lifted -- no specialised instances for unboxed lifted values
spec_infos_this_id = catMaybes (map head spec_infos)
spec_infos_rest = map tail spec_infos
bindTyVar :: TyVar -> UniType -> SpecM thing -> SpecM thing
bindTyVar tyvar ty specm sw_chkr tvenv idenv us
= specm sw_chkr (growTyVarEnvList tvenv [(tyvar,ty)]) idenv us
lookupId :: Id -> SpecM CloneInfo
lookupId id sw_chkr tvenv idenv us
= case lookupIdEnv idenv id of
Nothing -> NoLift (CoVarAtom id)
Just info -> info
specTy :: UniType -> SpecM UniType -- Apply the current type envt to the type
specTy ty sw_chkr tvenv idenv us
= applyTypeEnvToTy tvenv ty
liftId :: Id -> SpecM (Id, Id)
liftId id sw_chkr tvenv idenv us
= let
uniq = getSUnique us
mkLiftedId id uniq
In other monads these @mapSM@ things are usually called @listM@.
I think @mapSM@ is a much better name. The `2' and `3' variants are
when you want to return two or three results, and get at them
separately. It saves you having to do an (unzip stuff) right after.
mapSM :: (a -> SpecM b) -> [a] -> SpecM [b]
mapAndUnzipSM :: (a -> SpecM (b1, b2)) -> [a] -> SpecM ([b1],[b2])
mapAndUnzip3SM :: (a -> SpecM (b1, b2, b3)) -> [a] -> SpecM ([b1],[b2],[b3])
mapAndUnzip4SM :: (a -> SpecM (b1, b2, b3, b4)) -> [a] -> SpecM ([b1],[b2],[b3],[b4])
mapSM f [] = returnSM []
mapSM f (x:xs) = f x `thenSM` \ r ->
mapSM f xs `thenSM` \ rs ->
returnSM (r:rs)
mapAndUnzipSM f [] = returnSM ([],[])
mapAndUnzipSM f (x:xs) = f x `thenSM` \ (r1, r2) ->
mapAndUnzipSM f xs `thenSM` \ (rs1,rs2) ->
returnSM ((r1:rs1),(r2:rs2))
mapAndUnzip3SM f [] = returnSM ([],[],[])
mapAndUnzip3SM f (x:xs) = f x `thenSM` \ (r1,r2,r3) ->
mapAndUnzip3SM f xs `thenSM` \ (rs1,rs2,rs3) ->
returnSM ((r1:rs1),(r2:rs2),(r3:rs3))
mapAndUnzip4SM f [] = returnSM ([],[],[],[])
mapAndUnzip4SM f (x:xs) = f x `thenSM` \ (r1,r2,r3,r4) ->
mapAndUnzip4SM f xs `thenSM` \ (rs1,rs2,rs3,rs4) ->
returnSM ((r1:rs1),(r2:rs2),(r3:rs3),(r4:rs4))
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