\section[WorkWrap]{Worker/wrapper-generating back-end of strictness analyser}
\begin{code}
-#include "HsVersions.h"
-
-module WorkWrap ( workersAndWrappers ) where
+module WorkWrap ( workersAndWrappers, getWorkerIdAndCons ) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
import CoreSyn
-import CoreUnfold ( UnfoldingDetails(..){-ToDo:rm-}, UnfoldingGuidance(..) )
-IMPORT_DELOOPER(IdLoop) -- ToDo:rm when iWantToBeINLINEd goes
+import CoreUnfold ( Unfolding, certainlySmallEnoughToInline, calcUnfoldingGuidance )
+import CmdLineOpts ( opt_UnfoldingCreationThreshold )
import CoreUtils ( coreExprType )
-import Id ( idWantsToBeINLINEd, getIdStrictness, mkWorkerId,
- getIdInfo, replaceIdInfo, GenId
+import Id ( getInlinePragma, getIdStrictness, mkWorkerId,
+ addIdStrictness, addInlinePragma,
+ IdSet, emptyIdSet, addOneToIdSet,
+ GenId, Id
)
-import IdInfo ( noIdInfo, addInfo_UF, indicatesWorker,
- mkStrictnessInfo, StrictnessInfo(..)
+import IdInfo ( noIdInfo, addUnfoldInfo,
+ mkStrictnessInfo, addStrictnessInfo, StrictnessInfo(..)
)
import SaLib
-import UniqSupply ( returnUs, thenUs, mapUs, getUnique, SYN_IE(UniqSM) )
+import UniqSupply ( returnUs, thenUs, mapUs, getUnique, UniqSM )
import WwLib
-
-iWantToBeINLINEd :: UnfoldingGuidance -> UnfoldingDetails
-iWantToBeINLINEd x = NoUnfoldingDetails --ToDo:panic "WorkWrap.iWantToBeINLINEd (ToDo)"
+import Outputable
\end{code}
We take Core bindings whose binders have their strictness attached (by
The only reason this is monadised is for the unique supply.
\begin{code}
-tryWW :: Id -- the fn binder
- -> CoreExpr -- the bound rhs; its innards
+tryWW :: Id -- The fn binder
+ -> CoreExpr -- The bound rhs; its innards
-- are already ww'd
-> UniqSM [(Id, CoreExpr)] -- either *one* or *two* pairs;
-- if one, then no worker (only
-- if two, then a worker and a
-- wrapper.
tryWW fn_id rhs
- | idWantsToBeINLINEd fn_id
- -- No point in worker/wrappering something that is going to be
- -- INLINEd wholesale anyway. If the strictness analyser is run
- -- twice, this test also prevents wrappers (which are INLINEd)
- -- from being re-done.
- = do_nothing
-
- | otherwise
- = case (getIdStrictness fn_id) of
-
- NoStrictnessInfo -> do_nothing
- BottomGuaranteed -> do_nothing
- StrictnessInfo [] _ -> do_nothing -- V weird (but possible?)
-
- StrictnessInfo args_info _ ->
- if not (indicatesWorker args_info) then
- do_nothing
- else
-
- -- OK, it looks as if a worker is worth a try
- let
- (uvars, tyvars, args, body) = collectBinders rhs
- body_ty = coreExprType body
- in
- mkWwBodies body_ty tyvars args args_info `thenUs` \ result ->
- case result of
-
- Nothing -> -- Very peculiar. This can only happen if we hit an
- -- abstract type, which we shouldn't have since we've
- -- constructed the args_info in this module!
-
- -- False. We might hit the all-args-absent-and-the-
- -- body-is-unboxed case. A Nothing is legit. (WDP 94/10)
- do_nothing
-
- Just (wrapper_w_hole, worker_w_hole, worker_strictness, worker_ty_w_hole) ->
-
- -- Terrific! It worked!
- getUnique `thenUs` \ worker_uniq ->
- let
- worker_ty = worker_ty_w_hole body_ty
-
- worker_id = mkWorkerId worker_uniq fn_id worker_ty
- (noIdInfo `addInfo` worker_strictness)
-
- wrapper_rhs = wrapper_w_hole worker_id
- worker_rhs = worker_w_hole body
-
- revised_strictness_info
- = -- We know the basic strictness info already, but
- -- we need to slam in the exact identity of the
- -- worker Id:
- mkStrictnessInfo args_info (Just worker_id)
-
- wrapper_id = fn_id `replaceIdInfo`
- (getIdInfo fn_id `addInfo`
- revised_strictness_info `addInfo_UF`
- iWantToBeINLINEd UnfoldAlways)
- -- NB! the "iWantToBeINLINEd" part adds an INLINE pragma to
- -- the wrapper, which is of course what we want.
- in
- returnUs [ (worker_id, worker_rhs), -- worker comes first
- (wrapper_id, wrapper_rhs) ] -- because wrapper mentions it
+ | (certainlySmallEnoughToInline $
+ calcUnfoldingGuidance (getInlinePragma fn_id)
+ opt_UnfoldingCreationThreshold
+ rhs
+ )
+ -- No point in worker/wrappering something that is going to be
+ -- INLINEd wholesale anyway. If the strictness analyser is run
+ -- twice, this test also prevents wrappers (which are INLINEd)
+ -- from being re-done.
+
+ || not has_strictness_info
+ || not (worthSplitting revised_wrap_args_info)
+ = returnUs [ (fn_id, rhs) ]
+
+ | otherwise -- Do w/w split
+ = let
+ (tyvars, wrap_args, body) = collectBinders rhs
+ in
+ mkWwBodies tyvars wrap_args
+ (coreExprType body)
+ revised_wrap_args_info `thenUs` \ (wrap_fn, work_fn, work_demands) ->
+ getUnique `thenUs` \ work_uniq ->
+ let
+ work_rhs = work_fn body
+ work_id = mkWorkerId work_uniq fn_id (coreExprType work_rhs) work_info
+ work_info = noIdInfo `addStrictnessInfo` mkStrictnessInfo work_demands False
+
+ wrap_rhs = wrap_fn work_id
+ wrap_id = addInlinePragma (fn_id `addIdStrictness`
+ mkStrictnessInfo revised_wrap_args_info True)
+ -- Add info to the wrapper:
+ -- (a) we want to inline it everywhere
+ -- (b) we want to pin on its revised stricteness info
+ -- (c) we pin on its worker id and the list of constructors mentioned in the wrapper
+ in
+ returnUs ([(work_id, work_rhs), (wrap_id, wrap_rhs)])
+ -- Worker first, because wrapper mentions it
+ where
+ strictness_info = getIdStrictness fn_id
+ has_strictness_info = case strictness_info of
+ StrictnessInfo _ _ -> True
+ other -> False
+
+ wrap_args_info = case strictness_info of
+ StrictnessInfo args_info _ -> args_info
+ revised_wrap_args_info = setUnpackStrategy wrap_args_info
+
+-- This rather (nay! extremely!) crude function looks at a wrapper function, and
+-- snaffles out (a) the worker Id and (b) constructors needed to
+-- make the wrapper.
+-- These are needed when we write an interface file.
+getWorkerIdAndCons wrap_id wrapper_fn
+ = go wrapper_fn
where
- do_nothing = returnUs [ (fn_id, rhs) ]
+ go (Lam _ body) = go body
+ go (Case _ (AlgAlts [(con,_,rhs)] _)) = let (wrap_id, cons) = go rhs
+ in (wrap_id, cons `addOneToIdSet` con)
+ go (Let (NonRec _ (Coerce (CoerceOut con) _ _)) body)
+ = let (wrap_id, cons) = go body
+ in (wrap_id, cons `addOneToIdSet` con)
+ go other = (get_work_id other, emptyIdSet)
+
+ get_work_id (App fn _) = get_work_id fn
+ get_work_id (Var work_id) = work_id
+ get_work_id other = pprPanic "getWorkerIdAndCons" (ppr wrap_id)
\end{code}
projects / ghc-hetmet.git / blobdiff