#include "HsVersions.h"
import CoreSyn
-import CoreUtils ( coreExprType )
-import Id ( Id, idType, mkSysLocal, getIdDemandInfo, setIdDemandInfo,
+import CoreUtils ( exprType, mkInlineMe )
+import Id ( Id, idType, mkSysLocal, idDemandInfo, setIdDemandInfo,
isOneShotLambda, setOneShotLambda,
mkWildId, setIdInfo
)
import IdInfo ( CprInfo(..), noCprInfo, vanillaIdInfo )
-import Const ( Con(..), DataCon )
-import DataCon ( isExistentialDataCon, dataConArgTys )
-import Demand ( Demand(..) )
+import DataCon ( DataCon, splitProductType )
+import Demand ( Demand(..), wwLazy, wwPrim )
import PrelInfo ( realWorldPrimId, aBSENT_ERROR_ID )
import TysPrim ( realWorldStatePrimTy )
import TysWiredIn ( unboxedTupleCon, unboxedTupleTyCon )
import Type ( isUnLiftedType,
- splitForAllTys, splitFunTys,
+ splitForAllTys, splitFunTys, isAlgType,
splitAlgTyConApp_maybe, splitNewType_maybe,
mkTyConApp, mkFunTys,
Type
)
import TyCon ( isNewTyCon, isProductTyCon, TyCon )
import BasicTypes ( NewOrData(..), Arity )
-import Var ( TyVar, IdOrTyVar )
+import Var ( TyVar, Var, isId )
import UniqSupply ( returnUs, thenUs, getUniqueUs, getUniquesUs,
mapUs, UniqSM )
import Util ( zipWithEqual, zipEqual, lengthExceeds )
-> Bool -- True <=> the wrapper would not be an identity function
worthSplitting ds result_bot = any worth_it ds
-- We used not to split if the result is bottom.
- -- [Justification: there's no efficiency to be gained,
- -- and (worse) the wrapper body may not look like a wrapper
- -- body to getWorkerIdAndCons]
- -- But now (a) we don't have getWorkerIdAndCons, and
- -- (b) it's sometimes bad not to make a wrapper. Consider
+ -- [Justification: there's no efficiency to be gained.]
+ -- But it's sometimes bad not to make a wrapper. Consider
-- fw = \x# -> let x = I# x# in case e of
-- p1 -> error_fn x
-- p2 -> error_fn x
mkWwBodies :: Type -- Type of original function
-> Arity -- Arity of original function
-> [Demand] -- Strictness of original function
+ -> Bool -- True <=> function returns bottom
-> [Bool] -- One-shot-ness of the function
-> CprInfo -- Result of CPR analysis
- -> UniqSM ([IdOrTyVar], -- Worker args
+ -> UniqSM ([Demand], -- Demands for worker (value) args
Id -> CoreExpr, -- Wrapper body, lacking only the worker Id
CoreExpr -> CoreExpr) -- Worker body, lacking the original function rhs
-mkWwBodies fun_ty arity demands one_shots cpr_info
- = WARN( not (lengthExceeds demands (arity-1))
- || not (lengthExceeds one_shots (arity-1)),
- text "mkWrapper" <+> ppr fun_ty <+> ppr arity <+> ppr (take arity demands) <+> ppr (take arity one_shots) )
- mkWWargs fun_ty arity demands one_shots `thenUs` \ (wrap_args, wrap_fn_args, work_fn_args, res_ty) ->
- mkWWstr wrap_args `thenUs` \ (work_args, wrap_fn_str, work_fn_str) ->
- mkWWcpr res_ty cpr_info `thenUs` \ (wrap_fn_cpr, work_fn_cpr, cpr_res_ty) ->
- mkWWfixup cpr_res_ty work_args `thenUs` \ (wrap_fn_fixup, work_fn_fixup) ->
-
- returnUs (work_args,
- Note InlineMe . wrap_fn_args . wrap_fn_cpr . wrap_fn_str . wrap_fn_fixup . Var,
+mkWwBodies fun_ty arity demands res_bot one_shots cpr_info
+ = mkWWargs fun_ty arity demands' res_bot one_shots' `thenUs` \ (wrap_args, wrap_fn_args, work_fn_args, res_ty) ->
+ mkWWstr wrap_args `thenUs` \ (work_dmds, wrap_fn_str, work_fn_str) ->
+ mkWWcpr res_ty cpr_info `thenUs` \ (wrap_fn_cpr, work_fn_cpr, cpr_res_ty) ->
+ mkWWfixup cpr_res_ty work_dmds `thenUs` \ (final_work_dmds, wrap_fn_fixup, work_fn_fixup) ->
+
+ returnUs (final_work_dmds,
+ mkInlineMe . wrap_fn_args . wrap_fn_cpr . wrap_fn_str . wrap_fn_fixup . Var,
work_fn_fixup . work_fn_str . work_fn_cpr . work_fn_args)
+ where
+ demands' = demands ++ repeat wwLazy
+ one_shots' = one_shots ++ repeat False
\end{code}
the \x to get what we want.
\begin{code}
--- mkWWargs is driven off the function type.
+-- mkWWargs is driven off the function type and arity.
-- It chomps bites off foralls, arrows, newtypes
-- and keeps repeating that until it's satisfied the supplied arity
-mkWWargs :: Type -> Arity
- -> [Demand] -> [Bool] -- Both these will in due course be derived
+mkWWargs :: Type -> Arity
+ -> [Demand] -> Bool -> [Bool] -- Both these will in due course be derived
-- from the type. The [Bool] is True for a one-shot arg.
- -> UniqSM ([IdOrTyVar], -- Wrapper args
+ -- ** Both are infinite, extended with neutral values if necy **
+ -> UniqSM ([Var], -- Wrapper args
CoreExpr -> CoreExpr, -- Wrapper fn
CoreExpr -> CoreExpr, -- Worker fn
Type) -- Type of wrapper body
-mkWWargs fun_ty arity demands one_shots
- | arity == 0
- = returnUs ([], id, id, fun_ty)
-
- | otherwise
+mkWWargs fun_ty arity demands res_bot one_shots
+ | (res_bot || arity > 0) && (not (null tyvars) || n_arg_tys > 0)
+ -- If the function returns bottom, we feel free to
+ -- build lots of wrapper args:
+ -- \x. let v=E in \y. bottom
+ -- = \xy. let v=E in bottom
= getUniquesUs n_args `thenUs` \ wrap_uniqs ->
let
val_args = zipWith4 mk_wrap_arg wrap_uniqs arg_tys demands one_shots
wrap_args = tyvars ++ val_args
in
- mkWWargs body_rep_ty
+ mkWWargs new_fun_ty
(arity - n_args)
(drop n_args demands)
+ res_bot
(drop n_args one_shots) `thenUs` \ (more_wrap_args, wrap_fn_args, work_fn_args, res_ty) ->
returnUs (wrap_args ++ more_wrap_args,
- mkLams wrap_args . wrap_coerce_fn . wrap_fn_args,
- work_fn_args . work_coerce_fn . applyToVars wrap_args,
+ mkLams wrap_args . wrap_fn_args,
+ work_fn_args . applyToVars wrap_args,
res_ty)
where
(tyvars, tau) = splitForAllTys fun_ty
(arg_tys, body_ty) = splitFunTys tau
n_arg_tys = length arg_tys
- n_args = arity `min` n_arg_tys
- (wrap_coerce_fn, work_coerce_fn, body_rep_ty)
- | n_arg_tys == n_args -- All arg_tys used up
- = case splitNewType_maybe body_ty of
- Just rep_ty -> (Note (Coerce body_ty rep_ty), Note (Coerce rep_ty body_ty), rep_ty)
- Nothing -> ASSERT2( n_args /= 0, text "mkWWargs" <+> ppr arity <+> ppr fun_ty )
- (id, id, body_ty)
- | otherwise -- Leftover arg-tys
- = (id, id, mkFunTys (drop n_args arg_tys) body_ty)
-
-applyToVars :: [IdOrTyVar] -> CoreExpr -> CoreExpr
+ n_args | res_bot = n_arg_tys
+ | otherwise = arity `min` n_arg_tys
+ new_fun_ty | n_args == n_arg_tys = body_ty
+ | otherwise = mkFunTys (drop n_args arg_tys) body_ty
+
+mkWWargs fun_ty arity demands res_bot one_shots
+ = case splitNewType_maybe fun_ty of
+ Nothing -> returnUs ([], id, id, fun_ty)
+ Just rep_ty -> mkWWargs rep_ty arity demands res_bot one_shots `thenUs` \ (wrap_args, wrap_fn_args, work_fn_args, res_ty) ->
+ returnUs (wrap_args,
+ Note (Coerce fun_ty rep_ty) . wrap_fn_args,
+ work_fn_args . Note (Coerce rep_ty fun_ty),
+ res_ty)
+
+
+applyToVars :: [Var] -> CoreExpr -> CoreExpr
applyToVars vars fn = mkVarApps fn vars
mk_wrap_arg uniq ty dmd one_shot
%************************************************************************
\begin{code}
-mkWWfixup res_ty work_args
- | null work_args && isUnLiftedType res_ty
+mkWWfixup res_ty work_dmds
+ | null work_dmds && isUnLiftedType res_ty
-- Horrid special case. If the worker would have no arguments, and the
-- function returns a primitive type value, that would make the worker into
-- an unboxed value. We box it by passing a dummy void argument, thus:
let
void_arg = mk_ww_local void_arg_uniq realWorldStatePrimTy
in
- returnUs (\ call_to_worker -> App call_to_worker (Var realWorldPrimId),
+ returnUs ([wwPrim],
+ \ call_to_worker -> App call_to_worker (Var realWorldPrimId),
\ worker_body -> Lam void_arg worker_body)
| otherwise
- = returnUs (id, id)
+ = returnUs (work_dmds, id, id)
\end{code}
%************************************************************************
\begin{code}
-mkWWstr :: [IdOrTyVar] -- Wrapper args; have their demand info on them
+mkWWstr :: [Var] -- Wrapper args; have their demand info on them
-- *Includes type variables*
- -> UniqSM ([IdOrTyVar], -- Worker args
+ -> UniqSM ([Demand], -- Demand on worker (value) args
CoreExpr -> CoreExpr, -- Wrapper body, lacking the worker call
-- and without its lambdas
-- This fn adds the unboxing, and makes the
mkWWstr wrap_args
= mk_ww_str wrap_args `thenUs` \ (work_args, wrap_fn, work_fn) ->
- returnUs ( work_args,
+ returnUs ( [idDemandInfo v | v <- work_args, isId v],
\ wrapper_body -> wrap_fn (mkVarApps wrapper_body work_args),
\ worker_body -> mkLams work_args (work_fn worker_body))
returnUs (arg : worker_args, wrap_fn, work_fn)
| otherwise
- = case getIdDemandInfo arg of
+ = case idDemandInfo arg of
-- Absent case
WwLazy True ->
mkWWcpr body_ty NoCPRInfo
= returnUs (id, id, body_ty) -- Must be just the strictness transf.
-mkWWcpr body_ty (CPRInfo cpr_args)
+mkWWcpr body_ty ReturnsCPR
+ | not (isAlgType body_ty)
+ = WARN( True, text "mkWWcpr: non-algebraic body type" <+> ppr body_ty )
+ returnUs (id, id, body_ty)
+
| n_con_args == 1 && isUnLiftedType con_arg_ty1
-- Special case when there is a single result of unlifted type
= getUniquesUs 2 `thenUs` \ [work_uniq, arg_uniq] ->
arg = mk_ww_local arg_uniq con_arg_ty1
in
returnUs (\ wkr_call -> Case wkr_call arg [(DEFAULT, [], mkConApp data_con (map Type tycon_arg_tys ++ [Var arg]))],
- \ body -> Case body work_wild [(DataCon data_con, [arg], Var arg)],
+ \ body -> Case body work_wild [(DataAlt data_con, [arg], Var arg)],
con_arg_ty1)
| otherwise -- The general case
(wrap_wild : work_wild : args) = zipWith mk_ww_local uniqs (ubx_tup_ty : body_ty : con_arg_tys)
arg_vars = map Var args
ubx_tup_con = unboxedTupleCon n_con_args
- ubx_tup_ty = coreExprType ubx_tup_app
+ ubx_tup_ty = exprType ubx_tup_app
ubx_tup_app = mkConApp ubx_tup_con (map Type con_arg_tys ++ arg_vars)
con_app = mkConApp data_con (map Type tycon_arg_tys ++ arg_vars)
in
- returnUs (\ wkr_call -> Case wkr_call wrap_wild [(DataCon ubx_tup_con, args, con_app)],
- \ body -> Case body work_wild [(DataCon data_con, args, ubx_tup_app)],
+ returnUs (\ wkr_call -> Case wkr_call wrap_wild [(DataAlt ubx_tup_con, args, con_app)],
+ \ body -> Case body work_wild [(DataAlt data_con, args, ubx_tup_app)],
ubx_tup_ty)
where
(tycon, tycon_arg_tys, data_con, con_arg_tys) = splitProductType "mkWWcpr" body_ty
n_con_args = length con_arg_tys
con_arg_ty1 = head con_arg_tys
-
-
-splitProductType :: String -> Type -> (TyCon, [Type], DataCon, [Type])
- -- For a tiresome reason, the type might not look like a product type
- -- This happens when compiling the compiler! The module Name
- -- imports {-# SOURCE #-} TyCon and Id
- -- data Name = Name NameSort Unique OccName Provenance
- -- data NameSort = WiredInId Module Id | ...
- -- So Name does not look recursive (because Id is imported via a hi-boot file,
- -- which says nothing about Id's rep) but actually it is, because Ids have Names.
- -- Modules that *import* Name have a more complete view, see that Name is recursive,
- -- and therefore that it isn't a ProductType. This conflicts with the CPR info
- -- in exports from Name that say "do CPR".
- --
- -- Arguably we should regard Name as a product anyway because it isn't recursive
- -- via products all the way... but we don't have that info to hand, and even if
- -- we did this case might *still* arise.
-
- --
- -- So we hack our way out for now, by trusting the pragma that said "do CPR"
- -- that means we can't use splitProductType_maybe
-
-splitProductType fname ty
- = case splitAlgTyConApp_maybe ty of
- Just (tycon, tycon_args, (con:other_cons))
- | null other_cons && not (isExistentialDataCon con)
- -> WARN( not (isProductTyCon tycon),
- text "splitProductType hack: I happened!" <+> ppr ty )
- (tycon, tycon_args, con, dataConArgTys con tycon_args)
-
- other -> pprPanic (fname ++ ": not a product") (ppr ty)
\end{code}
-- A data type
= Case (Var arg)
(sanitiseCaseBndr arg)
- [(DataCon boxing_con, unpk_args, body)]
+ [(DataAlt boxing_con, unpk_args, body)]
sanitiseCaseBndr :: Id -> Id
-- The argument we are scrutinising has the right type to be
(unpk_arg:other_args) = unpk_args
mk_pk_let DataType arg boxing_con con_tys unpk_args body
- = Let (NonRec arg (Con (DataCon boxing_con) con_args)) body
+ = Let (NonRec arg (mkConApp boxing_con con_args)) body
where
con_args = map Type con_tys ++ map Var unpk_args
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