2 % (c) The GRASP/AQUA Project, Glasgow University, 1993-1996
4 \section[Specialise]{Stamping out overloading, and (optionally) polymorphism}
7 #include "HsVersions.h"
20 import Bag ( emptyBag, unitBag, isEmptyBag, unionBags,
21 partitionBag, listToBag, bagToList
23 import Class ( GenClass{-instance Eq-} )
24 import CmdLineOpts ( opt_SpecialiseImports, opt_D_simplifier_stats,
25 opt_CompilingPrelude, opt_SpecialiseTrace,
26 opt_SpecialiseOverloaded, opt_SpecialiseUnboxed,
29 import CoreLift ( mkLiftedId, liftExpr, bindUnlift, applyBindUnlifts )
31 import CoreUtils ( coreExprType, squashableDictishCcExpr )
32 import FiniteMap ( addListToFM_C )
33 import Id ( idType, isDefaultMethodId_maybe, toplevelishId,
34 isSuperDictSelId_maybe, isBottomingId,
35 isConstMethodId_maybe, isDataCon,
36 isImportedId, mkIdWithNewUniq,
37 dataConTyCon, applyTypeEnvToId,
38 nullIdEnv, addOneToIdEnv, growIdEnvList,
39 lookupIdEnv, IdEnv(..),
40 emptyIdSet, mkIdSet, unitIdSet,
41 elementOfIdSet, minusIdSet,
42 unionIdSets, unionManyIdSets, IdSet(..),
45 import Literal ( Literal{-instance Outputable-} )
46 import Maybes ( catMaybes, firstJust, maybeToBool )
47 import Name ( isLocallyDefined )
48 import Outputable ( interppSP, Outputable(..){-instance * []-} )
49 import PprStyle ( PprStyle(..) )
50 import PprType ( pprGenType, pprParendGenType, pprMaybeTy,
51 GenType{-instance Outputable-}, GenTyVar{-ditto-},
54 import PrelInfo ( liftDataCon )
55 import Pretty ( ppHang, ppCat, ppStr, ppAboves, ppBesides,
56 ppInt, ppSP, ppInterleave, ppNil, Pretty(..)
58 import PrimOp ( PrimOp(..) )
60 import Type ( mkTyVarTy, mkTyVarTys, isTyVarTy, getAppDataTyCon,
61 tyVarsOfTypes, applyTypeEnvToTy, isUnboxedType
63 import TyCon ( TyCon{-instance Eq-} )
64 import TyVar ( cloneTyVar,
65 elementOfTyVarSet, TyVarSet(..),
66 nullTyVarEnv, growTyVarEnvList, TyVarEnv(..),
67 GenTyVar{-instance Eq-}
69 import Unique ( Unique{-instance Eq-} )
70 import UniqSet ( mkUniqSet, unionUniqSets, uniqSetToList )
71 import UniqSupply ( splitUniqSupply, getUniques, getUnique )
72 import Util ( equivClasses, mapAccumL, assoc, zipWithEqual,
73 panic, pprTrace, pprPanic, assertPanic
79 data SpecInfo = SpecInfo [Maybe Type] Int Id
81 addIdSpecialisation = panic "Specialise.addIdSpecialisation (ToDo)"
82 cmpUniTypeMaybeList = panic "Specialise.cmpUniTypeMaybeList (ToDo)"
83 getIdSpecialisation = panic "Specialise.getIdSpecialisation (ToDo)"
84 isClassOpId = panic "Specialise.isClassOpId (ToDo)"
85 isDictTy = panic "Specialise.isDictTy (ToDo)"
86 isLocalGenTyCon = panic "Specialise.isLocalGenTyCon (ToDo)"
87 isLocalSpecTyCon = panic "Specialise.isLocalSpecTyCon (ToDo)"
88 isSpecId_maybe = panic "Specialise.isSpecId_maybe (ToDo)"
89 isSpecPragmaId_maybe = panic "Specialise.isSpecPragmaId_maybe (ToDo)"
90 lookupClassInstAtSimpleType = panic "Specialise.lookupClassInstAtSimpleType (ToDo)"
91 lookupSpecEnv = panic "Specialise.lookupSpecEnv (ToDo)"
92 mkPolySysTyVar = panic "Specialise.mkPolySysTyVar (ToDo)"
93 mkSpecEnv = panic "Specialise.mkSpecEnv (ToDo)"
94 mkSpecId = panic "Specialise.mkSpecId (ToDo)"
95 selectIdInfoForSpecId = panic "Specialise.selectIdInfoForSpecId (ToDo)"
96 specialiseTy = panic "Specialise.specialiseTy (ToDo)"
99 %************************************************************************
101 \subsection[notes-Specialise]{Implementation notes [SLPJ, Aug 18 1993]}
103 %************************************************************************
105 These notes describe how we implement specialisation to eliminate
106 overloading, and optionally to eliminate unboxed polymorphism, and
109 The specialisation pass is a partial evaluator which works on Core
110 syntax, complete with all the explicit dictionary application,
111 abstraction and construction as added by the type checker. The
112 existing type checker remains largely as it is.
114 One important thought: the {\em types} passed to an overloaded
115 function, and the {\em dictionaries} passed are mutually redundant.
116 If the same function is applied to the same type(s) then it is sure to
117 be applied to the same dictionary(s)---or rather to the same {\em
118 values}. (The arguments might look different but they will evaluate
121 Second important thought: we know that we can make progress by
122 treating dictionary arguments as static and worth specialising on. So
123 we can do without binding-time analysis, and instead specialise on
124 dictionary arguments and no others.
133 and suppose f is overloaded.
135 STEP 1: CALL-INSTANCE COLLECTION
137 We traverse <body>, accumulating all applications of f to types and
140 (Might there be partial applications, to just some of its types and
141 dictionaries? In principle yes, but in practice the type checker only
142 builds applications of f to all its types and dictionaries, so partial
143 applications could only arise as a result of transformation, and even
144 then I think it's unlikely. In any case, we simply don't accumulate such
145 partial applications.)
147 There's a choice of whether to collect details of all *polymorphic* functions
148 or simply all *overloaded* ones. How to sort this out?
149 Pass in a predicate on the function to say if it is "interesting"?
150 This is dependent on the user flags: SpecialiseOverloaded
156 So now we have a collection of calls to f:
160 Notice that f may take several type arguments. To avoid ambiguity, we
161 say that f is called at type t1/t2 and t3/t4.
163 We take equivalence classes using equality of the *types* (ignoring
164 the dictionary args, which as mentioned previously are redundant).
166 STEP 3: SPECIALISATION
168 For each equivalence class, choose a representative (f t1 t2 d1 d2),
169 and create a local instance of f, defined thus:
171 f@t1/t2 = <f_rhs> t1 t2 d1 d2
173 (f_rhs presumably has some big lambdas and dictionary lambdas, so lots
174 of simplification will now result.) Then we should recursively do
177 The new id has its own unique, but its print-name (if exported) has
178 an explicit representation of the instance types t1/t2.
180 Add this new id to f's IdInfo, to record that f has a specialised version.
182 Before doing any of this, check that f's IdInfo doesn't already
183 tell us about an existing instance of f at the required type/s.
184 (This might happen if specialisation was applied more than once, or
185 it might arise from user SPECIALIZE pragmas.)
189 Wait a minute! What if f is recursive? Then we can't just plug in
190 its right-hand side, can we?
192 But it's ok. The type checker *always* creates non-recursive definitions
193 for overloaded recursive functions. For example:
195 f x = f (x+x) -- Yes I know its silly
199 f a (d::Num a) = let p = +.sel a d
201 letrec fl (y::a) = fl (p y y)
205 We still have recusion for non-overloadd functions which we
206 speciailise, but the recursive call should get speciailised to the
207 same recursive version.
213 All this is crystal clear when the function is applied to *constant
214 types*; that is, types which have no type variables inside. But what if
215 it is applied to non-constant types? Suppose we find a call of f at type
216 t1/t2. There are two possibilities:
218 (a) The free type variables of t1, t2 are in scope at the definition point
219 of f. In this case there's no problem, we proceed just as before. A common
220 example is as follows. Here's the Haskell:
225 After typechecking we have
227 g a (d::Num a) (y::a) = let f b (d'::Num b) (x::b) = +.sel b d' x x
228 in +.sel a d (f a d y) (f a d y)
230 Notice that the call to f is at type type "a"; a non-constant type.
231 Both calls to f are at the same type, so we can specialise to give:
233 g a (d::Num a) (y::a) = let f@a (x::a) = +.sel a d x x
234 in +.sel a d (f@a y) (f@a y)
237 (b) The other case is when the type variables in the instance types
238 are *not* in scope at the definition point of f. The example we are
239 working with above is a good case. There are two instances of (+.sel a d),
240 but "a" is not in scope at the definition of +.sel. Can we do anything?
241 Yes, we can "common them up", a sort of limited common sub-expression deal.
244 g a (d::Num a) (y::a) = let +.sel@a = +.sel a d
245 f@a (x::a) = +.sel@a x x
246 in +.sel@a (f@a y) (f@a y)
248 This can save work, and can't be spotted by the type checker, because
249 the two instances of +.sel weren't originally at the same type.
253 * There are quite a few variations here. For example, the defn of
254 +.sel could be floated ouside the \y, to attempt to gain laziness.
255 It certainly mustn't be floated outside the \d because the d has to
258 * We don't want to inline f_rhs in this case, because
259 that will duplicate code. Just commoning up the call is the point.
261 * Nothing gets added to +.sel's IdInfo.
263 * Don't bother unless the equivalence class has more than one item!
265 Not clear whether this is all worth it. It is of course OK to
266 simply discard call-instances when passing a big lambda.
268 Polymorphism 2 -- Overloading
270 Consider a function whose most general type is
272 f :: forall a b. Ord a => [a] -> b -> b
274 There is really no point in making a version of g at Int/Int and another
275 at Int/Bool, because it's only instancing the type variable "a" which
276 buys us any efficiency. Since g is completely polymorphic in b there
277 ain't much point in making separate versions of g for the different
280 That suggests that we should identify which of g's type variables
281 are constrained (like "a") and which are unconstrained (like "b").
282 Then when taking equivalence classes in STEP 2, we ignore the type args
283 corresponding to unconstrained type variable. In STEP 3 we make
284 polymorphic versions. Thus:
286 f@t1/ = /\b -> <f_rhs> t1 b d1 d2
288 This seems pretty simple, and a Good Thing.
290 Polymorphism 3 -- Unboxed
293 If we are speciailising at unboxed types we must speciailise
294 regardless of the overloading constraint. In the exaple above it is
295 worth speciailising at types Int/Int#, Int/Bool# and a/Int#, Int#/Int#
298 Note that specialising an overloaded type at an uboxed type requires
299 an unboxed instance -- we cannot default to an unspecialised version!
306 f x = let g p q = p==q
312 Before specialisation, leaving out type abstractions we have
314 f df x = let g :: Eq a => a -> a -> Bool
316 h :: Num a => a -> a -> (a, Bool)
317 h dh r s = let deq = eqFromNum dh
318 in (+ dh r s, g deq r s)
322 After specialising h we get a specialised version of h, like this:
324 h' r s = let deq = eqFromNum df
325 in (+ df r s, g deq r s)
327 But we can't naively make an instance for g from this, because deq is not in scope
328 at the defn of g. Instead, we have to float out the (new) defn of deq
329 to widen its scope. Notice that this floating can't be done in advance -- it only
330 shows up when specialisation is done.
332 DELICATE MATTER: the way we tell a dictionary binding is by looking to
333 see if it has a Dict type. If the type has been "undictify'd", so that
334 it looks like a tuple, then the dictionary binding won't be floated, and
335 an opportunity to specialise might be lost.
337 User SPECIALIZE pragmas
338 ~~~~~~~~~~~~~~~~~~~~~~~
339 Specialisation pragmas can be digested by the type checker, and implemented
340 by adding extra definitions along with that of f, in the same way as before
342 f@t1/t2 = <f_rhs> t1 t2 d1 d2
344 Indeed the pragmas *have* to be dealt with by the type checker, because
345 only it knows how to build the dictionaries d1 and d2! For example
347 g :: Ord a => [a] -> [a]
348 {-# SPECIALIZE f :: [Tree Int] -> [Tree Int] #-}
350 Here, the specialised version of g is an application of g's rhs to the
351 Ord dictionary for (Tree Int), which only the type checker can conjure
352 up. There might not even *be* one, if (Tree Int) is not an instance of
353 Ord! (All the other specialision has suitable dictionaries to hand
356 Problem. The type checker doesn't have to hand a convenient <f_rhs>, because
357 it is buried in a complex (as-yet-un-desugared) binding group.
360 f@t1/t2 = f* t1 t2 d1 d2
362 where f* is the Id f with an IdInfo which says "inline me regardless!".
363 Indeed all the specialisation could be done in this way.
364 That in turn means that the simplifier has to be prepared to inline absolutely
365 any in-scope let-bound thing.
368 Again, the pragma should permit polymorphism in unconstrained variables:
370 h :: Ord a => [a] -> b -> b
371 {-# SPECIALIZE h :: [Int] -> b -> b #-}
373 We *insist* that all overloaded type variables are specialised to ground types,
374 (and hence there can be no context inside a SPECIALIZE pragma).
375 We *permit* unconstrained type variables to be specialised to
377 - or left as a polymorphic type variable
378 but nothing in between. So
380 {-# SPECIALIZE h :: [Int] -> [c] -> [c] #-}
382 is *illegal*. (It can be handled, but it adds complication, and gains the
386 SPECIALISING INSTANCE DECLARATIONS
387 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
390 instance Foo a => Foo [a] where
392 {-# SPECIALIZE instance Foo [Int] #-}
394 The original instance decl creates a dictionary-function
397 dfun.Foo.List :: forall a. Foo a -> Foo [a]
399 The SPECIALIZE pragma just makes a specialised copy, just as for
400 ordinary function definitions:
402 dfun.Foo.List@Int :: Foo [Int]
403 dfun.Foo.List@Int = dfun.Foo.List Int dFooInt
405 The information about what instance of the dfun exist gets added to
406 the dfun's IdInfo in the same way as a user-defined function too.
408 In fact, matters are a little bit more complicated than this.
409 When we make one of these specialised instances, we are defining
410 a constant dictionary, and so we want immediate access to its constant
411 methods and superclasses. Indeed, these constant methods and superclasses
412 must be in the IdInfo for the class selectors! We need help from the
413 typechecker to sort this out, perhaps by generating a separate IdInfo
416 Automatic instance decl specialisation?
417 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
418 Can instance decls be specialised automatically? It's tricky.
419 We could collect call-instance information for each dfun, but
420 then when we specialised their bodies we'd get new call-instances
421 for ordinary functions; and when we specialised their bodies, we might get
422 new call-instances of the dfuns, and so on. This all arises because of
423 the unrestricted mutual recursion between instance decls and value decls.
425 Furthermore, instance decls are usually exported and used non-locally,
426 so we'll want to compile enough to get those specialisations done.
428 Lastly, there's no such thing as a local instance decl, so we can
429 survive solely by spitting out *usage* information, and then reading that
430 back in as a pragma when next compiling the file. So for now,
431 we only specialise instance decls in response to pragmas.
433 That means that even if an instance decl ain't otherwise exported it
434 needs to be spat out as with a SPECIALIZE pragma. Furthermore, it needs
435 something to say which module defined the instance, so the usage info
436 can be fed into the right reqts info file. Blegh.
439 SPECIAILISING DATA DECLARATIONS
440 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
442 With unboxed specialisation (or full specialisation) we also require
443 data types (and their constructors) to be speciailised on unboxed
446 In addition to normal call instances we gather TyCon call instances at
447 unboxed types, determine equivalence classes for the locally defined
448 TyCons and build speciailised data constructor Ids for each TyCon and
449 substitute these in the Con calls.
451 We need the list of local TyCons to partition the TyCon instance info.
452 We pass out a FiniteMap from local TyCons to Specialised Instances to
453 give to the interface and code genertors.
455 N.B. The specialised data constructors reference the original data
456 constructor and type constructor which do not have the updated
457 specialisation info attached. Any specialisation info must be
458 extracted from the TyCon map returned.
461 SPITTING OUT USAGE INFORMATION
462 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
464 To spit out usage information we need to traverse the code collecting
465 call-instance information for all imported (non-prelude?) functions
466 and data types. Then we equivalence-class it and spit it out.
468 This is done at the top-level when all the call instances which escape
469 must be for imported functions and data types.
472 Partial specialisation by pragmas
473 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
474 What about partial specialisation:
476 k :: (Ord a, Eq b) => [a] -> b -> b -> [a]
477 {-# SPECIALIZE k :: Eq b => [Int] -> b -> b -> [a] #-}
481 {-# SPECIALIZE k :: Eq b => [Int] -> [b] -> [b] -> [a] #-}
483 Seems quite reasonable. Similar things could be done with instance decls:
485 instance (Foo a, Foo b) => Foo (a,b) where
487 {-# SPECIALIZE instance Foo a => Foo (a,Int) #-}
488 {-# SPECIALIZE instance Foo b => Foo (Int,b) #-}
490 Ho hum. Things are complex enough without this. I pass.
493 Requirements for the simplifer
494 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
495 The simplifier has to be able to take advantage of the specialisation.
497 * When the simplifier finds an application of a polymorphic f, it looks in
498 f's IdInfo in case there is a suitable instance to call instead. This converts
500 f t1 t2 d1 d2 ===> f_t1_t2
502 Note that the dictionaries get eaten up too!
504 * Dictionary selection operations on constant dictionaries must be
507 +.sel Int d ===> +Int
509 The obvious way to do this is in the same way as other specialised
510 calls: +.sel has inside it some IdInfo which tells that if it's applied
511 to the type Int then it should eat a dictionary and transform to +Int.
513 In short, dictionary selectors need IdInfo inside them for constant
516 * Exactly the same applies if a superclass dictionary is being
519 Eq.sel Int d ===> dEqInt
521 * Something similar applies to dictionary construction too. Suppose
522 dfun.Eq.List is the function taking a dictionary for (Eq a) to
523 one for (Eq [a]). Then we want
525 dfun.Eq.List Int d ===> dEq.List_Int
527 Where does the Eq [Int] dictionary come from? It is built in
528 response to a SPECIALIZE pragma on the Eq [a] instance decl.
530 In short, dfun Ids need IdInfo with a specialisation for each
531 constant instance of their instance declaration.
534 What does the specialisation IdInfo look like?
535 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
538 [Maybe Type] -- Instance types
539 Int -- No of dicts to eat
540 Id -- Specialised version
542 For example, if f has this SpecInfo:
544 SpecInfo [Just t1, Nothing, Just t3] 2 f'
548 f t1 t2 t3 d1 d2 ===> f t2
550 The "Nothings" identify type arguments in which the specialised
551 version is polymorphic.
553 What can't be done this way?
554 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
555 There is no way, post-typechecker, to get a dictionary for (say)
556 Eq a from a dictionary for Eq [a]. So if we find
560 we can't transform to
565 eqList :: (a->a->Bool) -> [a] -> [a] -> Bool
567 Of course, we currently have no way to automatically derive
568 eqList, nor to connect it to the Eq [a] instance decl, but you
569 can imagine that it might somehow be possible. Taking advantage
570 of this is permanently ruled out.
572 Still, this is no great hardship, because we intend to eliminate
573 overloading altogether anyway!
578 What about types/classes mentioned in SPECIALIZE pragmas spat out,
579 but not otherwise exported. Even if they are exported, what about
580 their original names.
582 Suggestion: use qualified names in pragmas, omitting module for
583 prelude and "this module".
590 f a (d::Num a) = let g = ...
592 ...(let d1::Ord a = Num.Ord.sel a d in g a d1)...
594 Here, g is only called at one type, but the dictionary isn't in scope at the
595 definition point for g. Usually the type checker would build a
596 definition for d1 which enclosed g, but the transformation system
597 might have moved d1's defn inward.
603 What should we do when a value is specialised to a *strict* unboxed value?
605 map_*_* f (x:xs) = let h = f x
609 Could convert let to case:
611 map_*_Int# f (x:xs) = case f x of h# ->
615 This may be undesirable since it forces evaluation here, but the value
616 may not be used in all branches of the body. In the general case this
617 transformation is impossible since the mutual recursion in a letrec
618 cannot be expressed as a case.
620 There is also a problem with top-level unboxed values, since our
621 implementation cannot handle unboxed values at the top level.
623 Solution: Lift the binding of the unboxed value and extract it when it
626 map_*_Int# f (x:xs) = let h = case (f x) of h# -> _Lift h#
631 Now give it to the simplifier and the _Lifting will be optimised away.
633 The benfit is that we have given the specialised "unboxed" values a
634 very simple lifted semantics and then leave it up to the simplifier to
635 optimise it --- knowing that the overheads will be removed in nearly
638 In particular, the value will only be evaluted in the branches of the
639 program which use it, rather than being forced at the point where the
640 value is bound. For example:
642 filtermap_*_* p f (x:xs)
649 filtermap_*_Int# p f (x:xs)
650 = let h = case (f x) of h# -> _Lift h#
653 True -> case h of _Lift h#
657 The binding for h can still be inlined in the one branch and the
661 Question: When won't the _Lifting be eliminated?
663 Answer: When they at the top-level (where it is necessary) or when
664 inlining would duplicate work (or possibly code depending on
665 options). However, the _Lifting will still be eliminated if the
666 strictness analyser deems the lifted binding strict.
670 %************************************************************************
672 \subsubsection[CallInstances]{@CallInstances@ data type}
674 %************************************************************************
677 type FreeVarsSet = IdSet
678 type FreeTyVarsSet = TyVarSet
682 Id -- This Id; *new* ie *cloned* id
683 [Maybe Type] -- Specialised at these types (*new*, cloned)
684 -- Nothing => no specialisation on this type arg
685 -- is required (flag dependent).
686 [CoreArg] -- And these dictionaries; all ValArgs
687 FreeVarsSet -- Free vars of the dict-args in terms of *new* ids
688 (Maybe SpecInfo) -- For specialisation with explicit SpecId
692 pprCI :: CallInstance -> Pretty
693 pprCI (CallInstance id spec_tys dicts _ maybe_specinfo)
694 = ppHang (ppCat [ppStr "Call inst for", ppr PprDebug id])
695 4 (ppAboves [ppCat (ppStr "types" : [pprMaybeTy PprDebug ty | ty <- spec_tys]),
696 case maybe_specinfo of
697 Nothing -> ppCat (ppStr "dicts" : [ppr_arg PprDebug dict | dict <- dicts])
698 Just (SpecInfo _ _ spec_id)
699 -> ppCat [ppStr "Explicit SpecId", ppr PprDebug spec_id]
702 -- ToDo: instance Outputable CoreArg?
703 ppr_arg sty (TyArg t) = ppr sty t
704 ppr_arg sty (LitArg i) = ppr sty i
705 ppr_arg sty (VarArg v) = ppr sty v
707 isUnboxedCI :: CallInstance -> Bool
708 isUnboxedCI (CallInstance _ spec_tys _ _ _)
709 = any isUnboxedType (catMaybes spec_tys)
711 isExplicitCI :: CallInstance -> Bool
712 isExplicitCI (CallInstance _ _ _ _ (Just _))
714 isExplicitCI (CallInstance _ _ _ _ Nothing)
718 Comparisons are based on the {\em types}, ignoring the dictionary args:
722 cmpCI :: CallInstance -> CallInstance -> TAG_
723 cmpCI (CallInstance id1 tys1 _ _ _) (CallInstance id2 tys2 _ _ _)
724 = case (id1 `cmp` id2) of { EQ_ -> cmpUniTypeMaybeList tys1 tys2; other -> other }
726 cmpCI_tys :: CallInstance -> CallInstance -> TAG_
727 cmpCI_tys (CallInstance _ tys1 _ _ _) (CallInstance _ tys2 _ _ _)
728 = cmpUniTypeMaybeList tys1 tys2
730 eqCI_tys :: CallInstance -> CallInstance -> Bool
732 = case cmpCI_tys c1 c2 of { EQ_ -> True; other -> False }
734 isCIofTheseIds :: [Id] -> CallInstance -> Bool
735 isCIofTheseIds ids (CallInstance ci_id _ _ _ _)
736 = any ((==) ci_id) ids
738 singleCI :: Id -> [Maybe Type] -> [CoreArg] -> UsageDetails
739 singleCI id tys dicts
740 = UsageDetails (unitBag (CallInstance id tys dicts fv_set Nothing))
741 emptyBag [] emptyIdSet 0 0
743 fv_set = mkIdSet (id : [dict | (VarArg dict) <- dicts])
745 explicitCI :: Id -> [Maybe Type] -> SpecInfo -> UsageDetails
746 explicitCI id tys specinfo
747 = UsageDetails (unitBag call_inst) emptyBag [] emptyIdSet 0 0
749 call_inst = CallInstance id tys dicts fv_set (Just specinfo)
750 dicts = panic "Specialise:explicitCI:dicts"
751 fv_set = unitIdSet id
753 -- We do not process the CIs for top-level dfuns or defms
754 -- Instead we require an explicit SPEC inst pragma for dfuns
755 -- and an explict method within any instances for the defms
757 getCIids :: Bool -> [Id] -> [Id]
758 getCIids True ids = filter not_dict_or_defm ids
762 = not (isDictTy (idType id) || maybeToBool (isDefaultMethodId_maybe id))
764 getCIs :: Bool -> [Id] -> UsageDetails -> ([CallInstance], UsageDetails)
765 getCIs top_lev ids (UsageDetails cis tycon_cis dbs fvs c i)
767 (cis_here, cis_not_here) = partitionBag (isCIofTheseIds (getCIids top_lev ids)) cis
768 cis_here_list = bagToList cis_here
770 -- pprTrace "getCIs:"
771 -- (ppHang (ppBesides [ppStr "{",
772 -- interppSP PprDebug ids,
774 -- 4 (ppAboves (map pprCI cis_here_list)))
775 (cis_here_list, UsageDetails cis_not_here tycon_cis dbs fvs c i)
777 dumpCIs :: Bag CallInstance -- The call instances
778 -> Bool -- True <=> top level bound Ids
779 -> Bool -- True <=> dict bindings to be floated (specBind only)
780 -> [CallInstance] -- Call insts for bound ids (instBind only)
781 -> [Id] -- Bound ids *new*
782 -> [Id] -- Full bound ids: includes dumped dicts
783 -> Bag CallInstance -- Kept call instances
785 -- CIs are dumped if:
786 -- 1) they are a CI for one of the bound ids, or
787 -- 2) they mention any of the dicts in a local unfloated binding
789 -- For top-level bindings we allow the call instances to
790 -- float past a dict bind and place all the top-level binds
791 -- in a *global* Rec.
792 -- We leave it to the simplifier will sort it all out ...
794 dumpCIs cis top_lev floating inst_cis bound_ids full_ids
795 = (if not (isEmptyBag cis_of_bound_id) &&
796 not (isEmptyBag cis_of_bound_id_without_inst_cis)
798 pprTrace ("dumpCIs: dumping CI which was not instantiated ... \n" ++
799 " (may be a non-HM recursive call)\n")
800 (ppHang (ppBesides [ppStr "{",
801 interppSP PprDebug bound_ids,
803 4 (ppAboves [ppStr "Dumping CIs:",
804 ppAboves (map pprCI (bagToList cis_of_bound_id)),
805 ppStr "Instantiating CIs:",
806 ppAboves (map pprCI inst_cis)]))
808 if top_lev || floating then
811 (if not (isEmptyBag cis_dump_unboxed)
812 then pprTrace "dumpCIs: bound dictionary arg ... WITH UNBOXED TYPES!\n"
813 (ppHang (ppBesides [ppStr "{",
814 interppSP PprDebug full_ids,
816 4 (ppAboves (map pprCI (bagToList cis_dump))))
818 cis_keep_not_bound_id
821 (cis_of_bound_id, cis_not_bound_id)
822 = partitionBag (isCIofTheseIds (getCIids top_lev bound_ids)) cis
824 (cis_dump, cis_keep_not_bound_id)
825 = partitionBag ok_to_dump_ci cis_not_bound_id
827 ok_to_dump_ci (CallInstance _ _ _ fv_set _)
828 = any (\ i -> i `elementOfIdSet` fv_set) full_ids
830 (_, cis_of_bound_id_without_inst_cis) = partitionBag have_inst_ci cis_of_bound_id
831 have_inst_ci ci = any (eqCI_tys ci) inst_cis
833 (cis_dump_unboxed, _) = partitionBag isUnboxedCI cis_dump
837 Any call instances of a bound_id can be safely dumped, because any
838 recursive calls should be at the same instance as the parent instance.
840 letrec f = /\a -> \x::a -> ...(f t x')...
842 Here, the type, t, at which f is used in its own RHS should be
843 just "a"; that is, the recursive call is at the same type as
844 the original call. That means that when specialising f at some
845 type, say Int#, we shouldn't find any *new* instances of f
846 arising from specialising f's RHS. The only instance we'll find
847 is another call of (f Int#).
849 We check this in dumpCIs by passing in all the instantiated call
850 instances (inst_cis) and reporting any dumped cis (cis_of_bound_id)
851 for which there is no such instance.
853 We also report CIs dumped due to a bound dictionary arg if they
854 contain unboxed types.
856 %************************************************************************
858 \subsubsection[TyConInstances]{@TyConInstances@ data type}
860 %************************************************************************
864 = TyConInstance TyCon -- Type Constructor
865 [Maybe Type] -- Applied to these specialising types
867 cmpTyConI :: TyConInstance -> TyConInstance -> TAG_
868 cmpTyConI (TyConInstance tc1 tys1) (TyConInstance tc2 tys2)
869 = case (cmp tc1 tc2) of { EQ_ -> cmpUniTypeMaybeList tys1 tys2; other -> other }
871 cmpTyConI_tys :: TyConInstance -> TyConInstance -> TAG_
872 cmpTyConI_tys (TyConInstance _ tys1) (TyConInstance _ tys2)
873 = cmpUniTypeMaybeList tys1 tys2
875 singleTyConI :: TyCon -> [Maybe Type] -> UsageDetails
876 singleTyConI ty_con spec_tys
877 = UsageDetails emptyBag (unitBag (TyConInstance ty_con spec_tys)) [] emptyIdSet 0 0
879 isTyConIofThisTyCon :: TyCon -> TyConInstance -> Bool
880 isTyConIofThisTyCon ty_con (TyConInstance inst_ty_con _) = ty_con == inst_ty_con
882 isLocalSpecTyConI :: Bool -> TyConInstance -> Bool
883 isLocalSpecTyConI comp_prel (TyConInstance inst_ty_con _) = isLocalSpecTyCon comp_prel inst_ty_con
885 getLocalSpecTyConIs :: Bool -> UsageDetails -> ([TyConInstance], UsageDetails)
886 getLocalSpecTyConIs comp_prel (UsageDetails cis tycon_cis dbs fvs c i)
888 (tycon_cis_local, tycon_cis_global)
889 = partitionBag (isLocalSpecTyConI comp_prel) tycon_cis
890 tycon_cis_local_list = bagToList tycon_cis_local
892 (tycon_cis_local_list, UsageDetails cis tycon_cis_global dbs fvs c i)
896 %************************************************************************
898 \subsubsection[UsageDetails]{@UsageDetails@ data type}
900 %************************************************************************
905 (Bag CallInstance) -- The collection of call-instances
906 (Bag TyConInstance) -- Constructor call-instances
907 [DictBindDetails] -- Dictionary bindings in data-dependence order!
908 FreeVarsSet -- Free variables (excl imported ones, incl top level) (cloned)
909 Int -- no. of spec calls
910 Int -- no. of spec insts
913 The DictBindDetails are fully processed; their call-instance information is
914 incorporated in the call-instances of the
915 UsageDetails which includes the DictBindDetails. The free vars in a usage details
916 will *include* the binders of the DictBind details.
918 A @DictBindDetails@ contains bindings for dictionaries *only*.
923 [Id] -- Main binders, originally visible in scope of binding (cloned)
924 CoreBinding -- Fully processed
925 FreeVarsSet -- Free in binding group (cloned)
926 FreeTyVarsSet -- Free in binding group
930 emptyUDs :: UsageDetails
931 unionUDs :: UsageDetails -> UsageDetails -> UsageDetails
932 unionUDList :: [UsageDetails] -> UsageDetails
934 tickSpecCall :: Bool -> UsageDetails -> UsageDetails
935 tickSpecInsts :: UsageDetails -> UsageDetails
937 tickSpecCall found (UsageDetails cis ty_cis dbs fvs c i)
938 = UsageDetails cis ty_cis dbs fvs (c + (if found then 1 else 0)) i
940 tickSpecInsts (UsageDetails cis ty_cis dbs fvs c i)
941 = UsageDetails cis ty_cis dbs fvs c (i+1)
943 emptyUDs = UsageDetails emptyBag emptyBag [] emptyIdSet 0 0
945 unionUDs (UsageDetails cis1 tycon_cis1 dbs1 fvs1 c1 i1) (UsageDetails cis2 tycon_cis2 dbs2 fvs2 c2 i2)
946 = UsageDetails (unionBags cis1 cis2) (unionBags tycon_cis1 tycon_cis2)
947 (dbs1 ++ dbs2) (fvs1 `unionIdSets` fvs2) (c1+c2) (i1+i2)
948 -- The append here is really redundant, since the bindings don't
949 -- scope over each other. ToDo.
951 unionUDList = foldr unionUDs emptyUDs
953 singleFvUDs (VarArg v) | not (isImportedId v)
954 = UsageDetails emptyBag emptyBag [] (unitIdSet v) 0 0
958 singleConUDs con = UsageDetails emptyBag emptyBag [] (unitIdSet con) 0 0
960 dumpDBs :: [DictBindDetails]
961 -> Bool -- True <=> top level bound Ids
962 -> [TyVar] -- TyVars being bound (cloned)
963 -> [Id] -- Ids being bound (cloned)
964 -> FreeVarsSet -- Fvs of body
965 -> ([CoreBinding], -- These ones have to go here
966 [DictBindDetails], -- These can float further
967 [Id], -- Incoming list + names of dicts bound here
968 FreeVarsSet -- Incoming fvs + fvs of dicts bound here
971 -- It is just to complex to try to float top-level
972 -- dict bindings with constant methods, inst methods,
973 -- auxillary derived instance defns and user instance
974 -- defns all getting in the way.
975 -- So we dump all dbinds as soon as we get to the top
976 -- level and place them in a *global* Rec.
977 -- We leave it to the simplifier will sort it all out ...
979 dumpDBs [] top_lev bound_tyvars bound_ids fvs
980 = ([], [], bound_ids, fvs)
982 dumpDBs ((db@(DictBindDetails dbinders dbind db_fvs db_ftv)):dbs)
983 top_lev bound_tyvars bound_ids fvs
985 || any (\ i -> i `elementOfIdSet` db_fvs) bound_ids
986 || any (\ t -> t `elementOfTyVarSet` db_ftv) bound_tyvars
987 = let -- Ha! Dump it!
988 (dbinds_here, dbs_outer, full_bound_ids, full_fvs)
989 = dumpDBs dbs top_lev bound_tyvars (dbinders ++ bound_ids) (db_fvs `unionIdSets` fvs)
991 (dbind : dbinds_here, dbs_outer, full_bound_ids, full_fvs)
993 | otherwise -- This one can float out further
995 (dbinds_here, dbs_outer, full_bound_ids, full_fvs)
996 = dumpDBs dbs top_lev bound_tyvars bound_ids fvs
998 (dbinds_here, db : dbs_outer, full_bound_ids, full_fvs)
1002 dumpUDs :: UsageDetails
1003 -> Bool -- True <=> top level bound Ids
1004 -> Bool -- True <=> dict bindings to be floated (specBind only)
1005 -> [CallInstance] -- Call insts for bound Ids (instBind only)
1006 -> [Id] -- Ids which are just being bound; *new*
1007 -> [TyVar] -- TyVars which are just being bound
1008 -> ([CoreBinding], -- Bindings from UsageDetails which mention the ids
1009 UsageDetails) -- The above bindings removed, and
1010 -- any call-instances which mention the ids dumped too
1012 dumpUDs (UsageDetails cis tycon_cis dbs fvs c i) top_lev floating inst_cis bound_ids tvs
1014 (dict_binds_here, dbs_outer, full_bound_ids, full_fvs)
1015 = dumpDBs dbs top_lev tvs bound_ids fvs
1016 cis_outer = dumpCIs cis top_lev floating inst_cis bound_ids full_bound_ids
1017 fvs_outer = full_fvs `minusIdSet` (mkIdSet full_bound_ids)
1019 (dict_binds_here, UsageDetails cis_outer tycon_cis dbs_outer fvs_outer c i)
1023 addDictBinds :: [Id] -> CoreBinding -> UsageDetails -- Dict binding and RHS usage
1024 -> UsageDetails -- The usage to augment
1026 addDictBinds dbinders dbind (UsageDetails db_cis db_tycon_cis db_dbs db_fvs db_c db_i)
1027 (UsageDetails cis tycon_cis dbs fvs c i)
1028 = UsageDetails (db_cis `unionBags` cis)
1029 (db_tycon_cis `unionBags` tycon_cis)
1030 (db_dbs ++ [DictBindDetails dbinders dbind db_fvs db_ftvs] ++ dbs)
1032 -- NB: We ignore counts from dictbinds since it is not user code
1034 -- The free tyvars of the dictionary bindings should really be
1035 -- gotten from the RHSs, but I'm pretty sure it's good enough just
1036 -- to look at the type of the dictionary itself.
1037 -- Doing the proper job would entail keeping track of free tyvars as
1038 -- well as free vars, which would be a bore.
1039 db_ftvs = tyVarsOfTypes (map idType dbinders)
1042 %************************************************************************
1044 \subsection[cloning-binders]{The Specialising IdEnv and CloneInfo}
1046 %************************************************************************
1048 @SpecIdEnv@ maps old Ids to their new "clone". There are three cases:
1050 1) (NoLift LitArg l) : an Id which is bound to a literal
1052 2) (NoLift LitArg l) : an Id bound to a "new" Id
1053 The new Id is a possibly-type-specialised clone of the original
1055 3) Lifted lifted_id unlifted_id :
1057 This indicates that the original Id has been specialised to an
1058 unboxed value which must be lifted (see "Unboxed bindings" above)
1059 @unlifted_id@ is the unboxed clone of the original Id
1060 @lifted_id@ is a *lifted* version of the original Id
1062 When you lookup Ids which are Lifted, you have to insert a case
1063 expression to un-lift the value (done with @bindUnlift@)
1065 You also have to insert a case to lift the value in the binding
1066 (done with @liftExpr@)
1070 type SpecIdEnv = IdEnv CloneInfo
1073 = NoLift CoreArg -- refers to cloned id or literal
1075 | Lifted Id -- lifted, cloned id
1076 Id -- unlifted, cloned id
1080 %************************************************************************
1082 \subsection[specialise-data]{Data returned by specialiser}
1084 %************************************************************************
1089 -- True <=> Specialisation performed
1091 -- False <=> Specialisation completed with errors
1094 -- Local tycons declared in this module
1097 -- Those in-scope data types for which we want to
1098 -- generate code for their constructors.
1099 -- Namely: data types declared in this module +
1100 -- any big tuples used in this module
1101 -- The initial (and default) value is the local tycons
1103 (FiniteMap TyCon [(Bool, [Maybe Type])])
1104 -- TyCon specialisations to be generated
1105 -- We generate specialialised code (Bool=True) for data types
1106 -- defined in this module and any tuples used in this module
1107 -- The initial (and default) value is the specialisations
1108 -- requested by source-level SPECIALIZE data pragmas (Bool=True)
1109 -- and _SPECIALISE_ pragmas (Bool=False) in the interface files
1111 (Bag (Id,[Maybe Type]))
1112 -- Imported specialisation errors
1113 (Bag (Id,[Maybe Type]))
1114 -- Imported specialisation warnings
1115 (Bag (TyCon,[Maybe Type]))
1116 -- Imported TyCon specialisation errors
1118 initSpecData local_tycons tycon_specs
1119 = SpecData False True local_tycons local_tycons tycon_specs emptyBag emptyBag emptyBag
1122 ToDo[sansom]: Transformation data to process specialisation requests.
1124 %************************************************************************
1126 \subsection[specProgram]{Specialising a core program}
1128 %************************************************************************
1131 specProgram :: UniqSupply
1132 -> [CoreBinding] -- input ...
1134 -> ([CoreBinding], -- main result
1135 SpecialiseData) -- result specialise data
1137 specProgram uniqs binds
1138 (SpecData False _ local_tycons _ init_specs init_errs init_warn init_tyerrs)
1139 = case (initSM (specTyConsAndScope (specTopBinds binds)) uniqs) of
1140 (final_binds, tycon_specs_list,
1141 UsageDetails import_cis import_tycis _ fvs spec_calls spec_insts)
1143 used_conids = filter isDataCon (uniqSetToList fvs)
1144 used_tycons = map dataConTyCon used_conids
1145 used_gen = filter isLocalGenTyCon used_tycons
1146 gen_tycons = uniqSetToList (mkUniqSet local_tycons `unionUniqSets` mkUniqSet used_gen)
1148 result_specs = addListToFM_C (++) init_specs tycon_specs_list
1150 uniq_cis = map head (equivClasses cmpCI (bagToList import_cis))
1151 cis_list = [(id, tys) | CallInstance id tys _ _ _ <- uniq_cis]
1152 (cis_unboxed, cis_other) = partition (isUnboxedSpecialisation . snd) cis_list
1153 cis_warn = init_warn `unionBags` listToBag cis_other
1154 cis_errs = init_errs `unionBags` listToBag cis_unboxed
1156 uniq_tycis = map head (equivClasses cmpTyConI (bagToList import_tycis))
1157 tycis_unboxed = [(con, tys) | TyConInstance con tys <- uniq_tycis]
1158 tycis_errs = init_tyerrs `unionBags` listToBag tycis_unboxed
1160 no_errs = isEmptyBag cis_errs && isEmptyBag tycis_errs
1161 && (not opt_SpecialiseImports || isEmptyBag cis_warn)
1163 (if opt_D_simplifier_stats then
1164 pprTrace "\nSpecialiser Stats:\n" (ppAboves [
1165 ppBesides [ppStr "SpecCalls ", ppInt spec_calls],
1166 ppBesides [ppStr "SpecInsts ", ppInt spec_insts],
1171 SpecData True no_errs local_tycons gen_tycons result_specs
1172 cis_errs cis_warn tycis_errs)
1174 specProgram uniqs binds (SpecData True _ _ _ _ _ _ _)
1175 = panic "Specialise:specProgram: specialiser called more than once"
1177 -- It may be possible safely to call the specialiser more than once,
1178 -- but I am not sure there is any benefit in doing so (Patrick)
1180 -- ToDo: What about unfoldings performed after specialisation ???
1183 %************************************************************************
1185 \subsection[specTyConsAndScope]{Specialising data constructors within tycons}
1187 %************************************************************************
1189 In the specialiser we just collect up the specialisations which will
1190 be required. We don't create the specialised constructors in
1191 Core. These are only introduced when we convert to StgSyn.
1193 ToDo: Perhaps this collection should be done in CoreToStg to ensure no inconsistencies!
1196 specTyConsAndScope :: SpecM ([CoreBinding], UsageDetails)
1197 -> SpecM ([CoreBinding], [(TyCon,[(Bool,[Maybe Type])])], UsageDetails)
1199 specTyConsAndScope scopeM
1200 = scopeM `thenSM` \ (binds, scope_uds) ->
1202 (tycons_cis, gotci_scope_uds)
1203 = getLocalSpecTyConIs opt_CompilingPrelude scope_uds
1205 tycon_specs_list = collectTyConSpecs tycons_cis
1207 (if opt_SpecialiseTrace && not (null tycon_specs_list) then
1208 pprTrace "Specialising TyCons:\n"
1209 (ppAboves [ if not (null specs) then
1210 ppHang (ppCat [(ppr PprDebug tycon), ppStr "at types"])
1211 4 (ppAboves (map pp_specs specs))
1213 | (tycon, specs) <- tycon_specs_list])
1215 returnSM (binds, tycon_specs_list, gotci_scope_uds)
1218 collectTyConSpecs []
1220 collectTyConSpecs tycons_cis@(TyConInstance tycon _ : _)
1221 = (tycon, tycon_specs) : collectTyConSpecs other_tycons_cis
1223 (tycon_cis, other_tycons_cis) = partition (isTyConIofThisTyCon tycon) tycons_cis
1224 uniq_cis = map head (equivClasses cmpTyConI_tys tycon_cis)
1225 tycon_specs = [(False, spec_tys) | TyConInstance _ spec_tys <- uniq_cis]
1227 pp_specs (False, spec_tys) = ppInterleave ppNil [pprMaybeTy PprDebug spec_ty | spec_ty <- spec_tys]
1231 %************************************************************************
1233 \subsection[specTopBinds]{Specialising top-level bindings}
1235 %************************************************************************
1238 specTopBinds :: [CoreBinding]
1239 -> SpecM ([CoreBinding], UsageDetails)
1242 = spec_top_binds binds `thenSM` \ (binds, UsageDetails cis tycis dbind_details fvs c i) ->
1244 -- Add bindings for floated dbinds and collect fvs
1245 -- In actual fact many of these bindings are dead code since dict
1246 -- arguments are dropped when a specialised call is created
1247 -- The simplifier should be able to cope ...
1249 (dbinders_s, dbinds, dfvs_s)
1250 = unzip3 [(dbinders, dbind, dfvs) | DictBindDetails dbinders dbind dfvs _ <- dbind_details]
1252 full_fvs = fvs `unionIdSets` unionManyIdSets dfvs_s
1253 fvs_outer = full_fvs `minusIdSet` (mkIdSet (concat dbinders_s))
1255 -- It is just to complex to try to sort out top-level dependencies
1256 -- So we just place all the top-level binds in a *global* Rec and
1257 -- leave it to the simplifier to sort it all out ...
1260 returnSM ([Rec (pairsFromCoreBinds binds)], UsageDetails cis tycis [] fvs_outer c i)
1263 spec_top_binds (first_bind:rest_binds)
1264 = specBindAndScope True first_bind (
1265 spec_top_binds rest_binds `thenSM` \ (rest_binds, rest_uds) ->
1266 returnSM (ItsABinds rest_binds, rest_uds)
1267 ) `thenSM` \ (first_binds, ItsABinds rest_binds, all_uds) ->
1268 returnSM (first_binds ++ rest_binds, all_uds)
1271 = returnSM ([], emptyUDs)
1274 %************************************************************************
1276 \subsection[specExpr]{Specialising expressions}
1278 %************************************************************************
1281 specExpr :: CoreExpr
1282 -> [CoreArg] -- The arguments:
1283 -- TypeArgs are speced
1284 -- ValArgs are unprocessed
1285 -> SpecM (CoreExpr, -- Result expression with specialised versions installed
1286 UsageDetails)-- Details of usage of enclosing binders in the result
1289 specExpr (Var v) args
1290 = lookupId v `thenSM` \ vlookup ->
1293 -> -- Binding has been lifted, need to extract un-lifted value
1294 -- NB: a function binding will never be lifted => args always null
1295 -- i.e. no call instance required or call to be constructed
1297 returnSM (bindUnlift vl vu (Var vu), singleFvUDs (VarArg vl))
1299 NoLift vatom@(VarArg new_v)
1300 -> mapSM specOutArg args `thenSM` \ arg_info ->
1301 mkCallInstance v new_v arg_info `thenSM` \ call_uds ->
1302 mkCall new_v arg_info `thenSM` \ ~(speced, call) ->
1304 uds = unionUDList [call_uds,
1306 unionUDList [uds | (_,uds,_) <- arg_info]
1309 returnSM (call, tickSpecCall speced uds)
1311 specExpr expr@(Lit _) null_args
1312 = ASSERT (null null_args)
1313 returnSM (expr, emptyUDs)
1315 specExpr (Con con args) null_args
1316 = ASSERT (null null_args)
1318 (targs, vargs) = partition_args args
1320 mapAndUnzipSM specTyArg targs `thenSM` \ (targs, tys) ->
1321 mapAndUnzip3SM specValArg vargs `thenSM` \ (vargs, args_uds_s, unlifts) ->
1322 mkTyConInstance con tys `thenSM` \ con_uds ->
1323 returnSM (applyBindUnlifts unlifts (Con con (targs ++ vargs)),
1324 unionUDList args_uds_s `unionUDs` con_uds)
1326 specExpr (Prim op@(CCallOp str is_asm may_gc arg_tys res_ty) args) null_args
1327 = ASSERT (null null_args)
1329 (targs, vargs) = partition_args args
1332 mapSM specTy arg_tys `thenSM` \ arg_tys ->
1333 specTy res_ty `thenSM` \ res_ty ->
1334 mapAndUnzip3SM specValArg vargs `thenSM` \ (vargs, args_uds_s, unlifts) ->
1335 returnSM (applyBindUnlifts unlifts (Prim (CCallOp str is_asm may_gc arg_tys res_ty) vargs),
1336 unionUDList args_uds_s)
1338 specExpr (Prim prim args) null_args
1339 = ASSERT (null null_args)
1341 (targs, vargs) = partition_args args
1343 mapAndUnzipSM specTyArg targs `thenSM` \ (targs, tys) ->
1344 mapAndUnzip3SM specValArg vargs `thenSM` \ (vargs, args_uds_s, unlifts) ->
1345 -- specPrimOp prim tys `thenSM` \ (prim, tys, prim_uds) ->
1346 returnSM (applyBindUnlifts unlifts (Prim prim (targs ++ vargs)),
1347 unionUDList args_uds_s {-`unionUDs` prim_uds-} )
1351 specPrimOp :: PrimOp
1357 -- Checks that PrimOp can handle (possibly unboxed) tys passed
1358 -- and/or chooses PrimOp specialised to any unboxed tys
1359 -- Errors are dealt with by returning a PrimOp call instance
1360 -- which will result in a cis_errs message
1362 -- ToDo: Deal with checkSpecTyApp for Prim in CoreLint
1366 specExpr (App fun arg) args
1367 = -- If TyArg, arg will be processed; otherwise, left alone
1368 preSpecArg arg `thenSM` \ new_arg ->
1369 specExpr fun (new_arg : args) `thenSM` \ (expr,uds) ->
1370 returnSM (expr, uds)
1372 specExpr (Lam (ValBinder binder) body) (arg : args) | isValArg arg
1373 = lookup_arg arg `thenSM` \ arg ->
1374 bindId binder arg (specExpr body args)
1376 lookup_arg (LitArg l) = returnSM (NoLift (LitArg l))
1377 lookup_arg (VarArg v) = lookupId v
1379 specExpr (Lam (ValBinder binder) body) []
1380 = specLambdaOrCaseBody [binder] body [] `thenSM` \ ([binder], body, uds) ->
1381 returnSM (Lam (ValBinder binder) body, uds)
1383 specExpr (Lam (TyBinder tyvar) body) (TyArg ty : args)
1384 = -- Type lambda with argument; argument already spec'd
1385 bindTyVar tyvar ty ( specExpr body args )
1387 specExpr (Lam (TyBinder tyvar) body) []
1389 cloneTyVarSM tyvar `thenSM` \ new_tyvar ->
1390 bindTyVar tyvar (mkTyVarTy new_tyvar) (
1391 specExpr body [] `thenSM` \ (body, body_uds) ->
1393 (binds_here, final_uds) = dumpUDs body_uds False False [] [] [new_tyvar]
1395 returnSM (Lam (TyBinder new_tyvar)
1396 (mkCoLetsNoUnboxed binds_here body),
1400 specExpr (Case scrutinee alts) args
1401 = specExpr scrutinee [] `thenSM` \ (scrutinee, scrut_uds) ->
1402 specAlts alts scrutinee_type args `thenSM` \ (alts, alts_uds) ->
1403 returnSM (Case scrutinee alts, scrut_uds `unionUDs` alts_uds)
1405 scrutinee_type = coreExprType scrutinee
1407 specExpr (Let bind body) args
1408 = specBindAndScope False bind (
1409 specExpr body args `thenSM` \ (body, body_uds) ->
1410 returnSM (ItsAnExpr body, body_uds)
1411 ) `thenSM` \ (binds, ItsAnExpr body, all_uds) ->
1412 returnSM (mkCoLetsUnboxedToCase binds body, all_uds)
1414 specExpr (SCC cc expr) args
1415 = specExpr expr [] `thenSM` \ (expr, expr_uds) ->
1416 mapAndUnzip3SM specOutArg args `thenSM` \ (args, args_uds_s, unlifts) ->
1419 = if squashableDictishCcExpr cc expr -- can toss the _scc_
1423 returnSM (applyBindUnlifts unlifts (mkGenApp scc_expr args),
1424 unionUDList args_uds_s `unionUDs` expr_uds)
1426 specExpr (Coerce _ _ _) args = panic "Specialise.specExpr:Coerce"
1428 -- ToDo: This may leave some unspec'd dictionaries!!
1431 %************************************************************************
1433 \subsubsection{Specialising a lambda}
1435 %************************************************************************
1438 specLambdaOrCaseBody :: [Id] -- The binders
1439 -> CoreExpr -- The body
1440 -> [CoreArg] -- Its args
1441 -> SpecM ([Id], -- New binders
1442 CoreExpr, -- New body
1445 specLambdaOrCaseBody bound_ids body args
1446 = cloneLambdaOrCaseBinders bound_ids `thenSM` \ (new_ids, clone_infos) ->
1447 bindIds bound_ids clone_infos (
1449 specExpr body args `thenSM` \ (body, body_uds) ->
1452 -- Dump any dictionary bindings (and call instances)
1453 -- from the scope which mention things bound here
1454 (binds_here, final_uds) = dumpUDs body_uds False False [] new_ids []
1456 returnSM (new_ids, mkCoLetsNoUnboxed binds_here body, final_uds)
1459 -- ToDo: Opportunity here to common-up dictionaries with same type,
1460 -- thus avoiding recomputation.
1463 A variable bound in a lambda or case is normally monomorphic so no
1464 specialised versions will be required. This is just as well since we
1465 do not know what code to specialise!
1467 Unfortunately this is not always the case. For example a class Foo
1468 with polymorphic methods gives rise to a dictionary with polymorphic
1469 components as follows:
1476 instance Foo Int where
1484 d.Foo.Int :: ( \/b . Int -> b -> Int, \/c . Int -> c -> Int )
1485 d.Foo.Int = (op1_Int, op2_Int)
1487 op1 = /\ a b -> \ dFoo -> case dFoo of (meth1, _) -> meth1 b
1489 ... op1 {Int Int#} d.Foo.Int 1 3# ...
1492 N.B. The type of the dictionary is not Hindley Milner!
1494 Now we must specialise op1 at {* Int#} which requires a version of
1495 meth1 at {Int#}. But since meth1 was extracted from a dictionary we do
1496 not have access to its code to create the specialised version.
1498 If we specialise on overloaded types as well we specialise op1 at
1499 {Int Int#} d.Foo.Int:
1501 op1_Int_Int# = case d.Foo.Int of (meth1, _) -> meth1 {Int#}
1503 Though this is still invalid, after further simplification we get:
1505 op1_Int_Int# = opInt1 {Int#}
1507 Another round of specialisation will result in the specialised
1508 version of op1Int being called directly.
1510 For now we PANIC if a polymorphic lambda/case bound variable is found
1511 in a call instance with an unboxed type. Other call instances, arising
1512 from overloaded type arguments, are discarded since the unspecialised
1513 version extracted from the method can be called as normal.
1515 ToDo: Implement and test second round of specialisation.
1518 %************************************************************************
1520 \subsubsection{Specialising case alternatives}
1522 %************************************************************************
1526 specAlts (AlgAlts alts deflt) scrutinee_ty args
1527 = mapSM specTy ty_args `thenSM` \ ty_args ->
1528 mapAndUnzipSM (specAlgAlt ty_args) alts `thenSM` \ (alts, alts_uds_s) ->
1529 specDeflt deflt args `thenSM` \ (deflt, deflt_uds) ->
1530 returnSM (AlgAlts alts deflt,
1531 unionUDList alts_uds_s `unionUDs` deflt_uds)
1533 -- We use ty_args of scrutinee type to identify specialisation of
1536 (_, ty_args, _) = getAppDataTyCon scrutinee_ty
1538 specAlgAlt ty_args (con,binders,rhs)
1539 = specLambdaOrCaseBody binders rhs args `thenSM` \ (binders, rhs, rhs_uds) ->
1540 mkTyConInstance con ty_args `thenSM` \ con_uds ->
1541 returnSM ((con,binders,rhs), rhs_uds `unionUDs` con_uds)
1543 specAlts (PrimAlts alts deflt) scrutinee_ty args
1544 = mapAndUnzipSM specPrimAlt alts `thenSM` \ (alts, alts_uds_s) ->
1545 specDeflt deflt args `thenSM` \ (deflt, deflt_uds) ->
1546 returnSM (PrimAlts alts deflt,
1547 unionUDList alts_uds_s `unionUDs` deflt_uds)
1549 specPrimAlt (lit,rhs) = specExpr rhs args `thenSM` \ (rhs, uds) ->
1550 returnSM ((lit,rhs), uds)
1553 specDeflt NoDefault args = returnSM (NoDefault, emptyUDs)
1554 specDeflt (BindDefault binder rhs) args
1555 = specLambdaOrCaseBody [binder] rhs args `thenSM` \ ([binder], rhs, uds) ->
1556 returnSM (BindDefault binder rhs, uds)
1560 %************************************************************************
1562 \subsubsection{Specialising an atom}
1564 %************************************************************************
1567 partition_args :: [CoreArg] -> ([CoreArg], [CoreArg])
1569 = span is_ty_arg args
1571 is_ty_arg (TyArg _) = True
1575 preSpecArg :: CoreArg -> SpecM CoreArg -- diddle TyArgs, but nothing else
1577 preSpecArg (TyArg ty)
1578 = specTy ty `thenSM` \ new_ty ->
1579 returnSM (TyArg new_ty)
1581 preSpecArg other = returnSM other
1583 --------------------
1584 specValArg :: CoreArg -> SpecM (CoreArg, UsageDetails,
1585 CoreExpr -> CoreExpr)
1587 specValArg (LitArg lit)
1588 = returnSM (LitArg lit, emptyUDs, id)
1590 specValArg (VarArg v)
1591 = lookupId v `thenSM` \ vlookup ->
1594 -> returnSM (VarArg vu, singleFvUDs (VarArg vl), bindUnlift vl vu)
1597 -> returnSM (vatom, singleFvUDs vatom, id)
1601 specTyArg (TyArg ty)
1602 = specTy ty `thenSM` \ new_ty ->
1603 returnSM (TyArg new_ty, new_ty)
1606 specOutArg :: CoreArg -> SpecM (CoreArg, UsageDetails,
1607 CoreExpr -> CoreExpr)
1609 specOutArg (TyArg ty) -- already speced; no action
1610 = returnSM (TyArg ty, emptyUDs, id)
1612 specOutArg other_arg -- unprocessed; spec the atom
1613 = specValArg other_arg
1617 %************************************************************************
1619 \subsubsection{Specialising bindings}
1621 %************************************************************************
1623 A classic case of when having a polymorphic recursive function would help!
1626 data BindsOrExpr = ItsABinds [CoreBinding]
1627 | ItsAnExpr CoreExpr
1632 :: Bool -- True <=> a top level group
1633 -> CoreBinding -- As yet unprocessed
1634 -> SpecM (BindsOrExpr, UsageDetails) -- Something to do the scope of the bindings
1635 -> SpecM ([CoreBinding], -- Processed
1636 BindsOrExpr, -- Combined result
1637 UsageDetails) -- Usage details of the whole lot
1639 specBindAndScope top_lev bind scopeM
1640 = cloneLetBinders top_lev (is_rec bind) binders
1641 `thenSM` \ (new_binders, clone_infos) ->
1643 -- Two cases now: either this is a bunch of local dictionaries,
1644 -- in which case we float them; or its a bunch of other values,
1645 -- in which case we see if they correspond to any call-instances
1646 -- we have from processing the scope
1648 if not top_lev && all (isDictTy . idType) binders
1650 -- Ha! A group of local dictionary bindings
1652 bindIds binders clone_infos (
1654 -- Process the dictionary bindings themselves
1655 specBind False True new_binders [] bind `thenSM` \ (bind, rhs_uds) ->
1657 -- Process their scope
1658 scopeM `thenSM` \ (thing, scope_uds) ->
1660 -- Add the bindings to the current stuff
1661 final_uds = addDictBinds new_binders bind rhs_uds scope_uds
1663 returnSM ([], thing, final_uds)
1666 -- Ho! A group of bindings
1668 fixSM (\ ~(_, _, _, rec_spec_infos) ->
1670 bindSpecIds binders clone_infos rec_spec_infos (
1671 -- It's ok to have new binders in scope in
1672 -- non-recursive decls too, cos name shadowing is gone by now
1674 -- Do the scope of the bindings
1675 scopeM `thenSM` \ (thing, scope_uds) ->
1677 (call_insts, gotci_scope_uds) = getCIs top_lev new_binders scope_uds
1679 equiv_ciss = equivClasses cmpCI_tys call_insts
1680 inst_cis = map head equiv_ciss
1683 -- Do the bindings themselves
1684 specBind top_lev False new_binders inst_cis bind
1685 `thenSM` \ (spec_bind, spec_uds) ->
1687 -- Create any necessary instances
1688 instBind top_lev new_binders bind equiv_ciss inst_cis
1689 `thenSM` \ (inst_binds, inst_uds, spec_infos) ->
1692 -- NB: dumpUDs only worries about new_binders since the free var
1693 -- stuff only records free new_binders
1694 -- The spec_ids only appear in SpecInfos and final speced calls
1696 -- Build final binding group and usage details
1697 (final_binds, final_uds)
1699 -- For a top-level binding we have to dumpUDs from
1700 -- spec_uds and inst_uds and scope_uds creating
1701 -- *global* dict bindings
1703 (scope_dict_binds, final_scope_uds)
1704 = dumpUDs gotci_scope_uds True False [] new_binders []
1705 (spec_dict_binds, final_spec_uds)
1706 = dumpUDs spec_uds True False inst_cis new_binders []
1707 (inst_dict_binds, final_inst_uds)
1708 = dumpUDs inst_uds True False inst_cis new_binders []
1710 ([spec_bind] ++ inst_binds ++ scope_dict_binds
1711 ++ spec_dict_binds ++ inst_dict_binds,
1712 final_spec_uds `unionUDs` final_scope_uds `unionUDs` final_inst_uds)
1714 -- For a local binding we only have to dumpUDs from
1715 -- scope_uds since the UDs from spec_uds and inst_uds
1716 -- have already been dumped by specBind and instBind
1718 (scope_dict_binds, final_scope_uds)
1719 = dumpUDs gotci_scope_uds False False [] new_binders []
1721 ([spec_bind] ++ inst_binds ++ scope_dict_binds,
1722 spec_uds `unionUDs` final_scope_uds `unionUDs` inst_uds)
1724 -- inst_uds comes last, because there may be dict bindings
1725 -- floating outward in scope_uds which are mentioned
1726 -- in the call-instances, and hence in spec_uds.
1727 -- This ordering makes sure that the precedence order
1728 -- among the dict bindings finally floated out is maintained.
1730 returnSM (final_binds, thing, final_uds, spec_infos)
1732 ) `thenSM` \ (binds, thing, final_uds, spec_infos) ->
1733 returnSM (binds, thing, final_uds)
1735 binders = bindersOf bind
1737 is_rec (NonRec _ _) = False
1742 specBind :: Bool -> Bool -> [Id] -> [CallInstance]
1744 -> SpecM (CoreBinding, UsageDetails)
1745 -- The UsageDetails returned has already had stuff to do with this group
1746 -- of binders deleted; that's why new_binders is passed in.
1747 specBind top_lev floating new_binders inst_cis (NonRec binder rhs)
1748 = specOneBinding top_lev floating new_binders inst_cis (binder,rhs)
1749 `thenSM` \ ((binder,rhs), rhs_uds) ->
1750 returnSM (NonRec binder rhs, rhs_uds)
1752 specBind top_lev floating new_binders inst_cis (Rec pairs)
1753 = mapAndUnzipSM (specOneBinding top_lev floating new_binders inst_cis) pairs
1754 `thenSM` \ (pairs, rhs_uds_s) ->
1755 returnSM (Rec pairs, unionUDList rhs_uds_s)
1758 specOneBinding :: Bool -> Bool -> [Id] -> [CallInstance]
1760 -> SpecM ((Id,CoreExpr), UsageDetails)
1762 specOneBinding top_lev floating new_binders inst_cis (binder, rhs)
1763 = lookupId binder `thenSM` \ blookup ->
1764 specExpr rhs [] `thenSM` \ (rhs, rhs_uds) ->
1766 specid_maybe_maybe = isSpecPragmaId_maybe binder
1767 is_specid = maybeToBool specid_maybe_maybe
1768 Just specinfo_maybe = specid_maybe_maybe
1769 specid_with_info = maybeToBool specinfo_maybe
1770 Just spec_info = specinfo_maybe
1772 -- If we have a SpecInfo stored in a SpecPragmaId binder
1773 -- it will contain a SpecInfo with an explicit SpecId
1774 -- We add the explicit ci to the usage details
1775 -- Any ordinary cis for orig_id (there should only be one)
1776 -- will be ignored later
1779 = if is_specid && specid_with_info then
1781 (SpecInfo spec_tys _ spec_id) = spec_info
1782 Just (orig_id, _) = isSpecId_maybe spec_id
1784 ASSERT(toplevelishId orig_id) -- must not be cloned!
1785 explicitCI orig_id spec_tys spec_info
1789 -- For a local binding we dump the usage details, creating
1790 -- any local dict bindings required
1791 -- At the top-level the uds will be dumped in specBindAndScope
1792 -- and the dict bindings made *global*
1794 (local_dict_binds, final_uds)
1795 = if not top_lev then
1796 dumpUDs rhs_uds False floating inst_cis new_binders []
1801 Lifted lift_binder unlift_binder
1802 -> -- We may need to record an unboxed instance of
1803 -- the _Lift data type in the usage details
1804 mkTyConInstance liftDataCon [idType unlift_binder]
1805 `thenSM` \ lift_uds ->
1806 returnSM ((lift_binder,
1807 mkCoLetsNoUnboxed local_dict_binds (liftExpr unlift_binder rhs)),
1808 final_uds `unionUDs` pragma_uds `unionUDs` lift_uds)
1810 NoLift (VarArg binder)
1811 -> returnSM ((binder, mkCoLetsNoUnboxed local_dict_binds rhs),
1812 final_uds `unionUDs` pragma_uds)
1816 %************************************************************************
1818 \subsection{@instBind@}
1820 %************************************************************************
1823 instBind top_lev new_ids@(first_binder:other_binders) bind equiv_ciss inst_cis
1825 = returnSM ([], emptyUDs, [])
1827 | all same_overloading other_binders
1828 = -- For each call_inst, build an instance
1829 mapAndUnzip3SM do_this_class equiv_ciss
1830 `thenSM` \ (inst_binds, inst_uds_s, spec_infos) ->
1832 -- Add in the remaining UDs
1833 returnSM (catMaybes inst_binds,
1834 unionUDList inst_uds_s,
1838 | otherwise -- Incompatible overloadings; see below by same_overloading
1839 = (if not (null (filter isUnboxedCI (concat equiv_ciss)))
1840 then pprTrace "dumpCIs: not same overloading ... WITH UNBOXED TYPES!\n"
1842 then pprTrace "dumpCIs: not same overloading ... top level \n"
1844 ) (ppHang (ppBesides [ppStr "{",
1845 interppSP PprDebug new_ids,
1847 4 (ppAboves [ppAboves (map (pprGenType PprDebug . idType) new_ids),
1848 ppAboves (map pprCI (concat equiv_ciss))]))
1849 (returnSM ([], emptyUDs, []))
1852 (tyvar_tmpls, class_tyvar_pairs) = getIdOverloading first_binder
1853 tyvar_tmpl_tys = mkTyVarTys tyvar_tmpls
1855 no_of_tyvars = length tyvar_tmpls
1856 no_of_dicts = length class_tyvar_pairs
1858 do_this_class equiv_cis
1859 = mkOneInst do_cis explicit_cis no_of_dicts top_lev inst_cis new_ids bind
1861 (explicit_cis, normal_cis) = partition isExplicitCI equiv_cis
1862 do_cis = head (normal_cis ++ explicit_cis)
1863 -- must choose a normal_cis in preference since dict_args will
1864 -- not be defined for an explicit_cis
1866 -- same_overloading tests whether the types of all the binders
1867 -- are "compatible"; ie have the same type and dictionary abstractions
1868 -- Almost always this is the case, because a recursive group is abstracted
1869 -- all together. But, it can happen that it ain't the case, because of
1870 -- code generated from instance decls:
1873 -- dfun.Foo.Int :: (forall a. a -> Int, Int)
1874 -- dfun.Foo.Int = (const.op1.Int, const.op2.Int)
1876 -- const.op1.Int :: forall a. a -> Int
1877 -- const.op1.Int a = defm.Foo.op1 Int a dfun.Foo.Int
1879 -- const.op2.Int :: Int
1880 -- const.op2.Int = 3
1882 -- Note that the first two defns have different polymorphism, but they are
1883 -- mutually recursive!
1885 same_overloading :: Id -> Bool
1887 = no_of_tyvars == length this_id_tyvars
1888 -- Same no of tyvars
1889 && no_of_dicts == length this_id_class_tyvar_pairs
1890 -- Same no of vdicts
1891 && and (zipWith same_ov class_tyvar_pairs this_id_class_tyvar_pairs)
1892 && length class_tyvar_pairs == length this_id_class_tyvar_pairs
1895 (this_id_tyvars, this_id_class_tyvar_pairs) = getIdOverloading id
1896 tyvar_pairs = this_id_tyvars `zip` tyvar_tmpls
1898 same_ov (clas1,tyvar1) (clas2,tyvar2)
1900 tyvar1 == assoc "same_overloading" tyvar_pairs tyvar2
1904 - a call instance eg f [t1,t2,t3] [d1,d2]
1905 - the rhs of the function eg orig_rhs
1906 - a constraint vector, saying which of eg [T,F,T]
1907 the functions type args are constrained
1910 We return a new definition
1912 f@t1//t3 = /\a -> orig_rhs t1 a t3 d1 d2
1914 The SpecInfo for f will be (the "2" indicates 2 dictionaries to eat)
1916 SpecInfo [Just t1, Nothing, Just t3] 2 f@t1//t3
1918 Based on this SpecInfo, a call instance of f
1920 ...(f t1 t2 t3 d1 d2)...
1922 should get replaced by
1926 (But that is the business of @mkCall@.)
1929 mkOneInst :: CallInstance
1930 -> [CallInstance] -- Any explicit cis for this inst
1931 -> Int -- No of dicts to specialise
1932 -> Bool -- Top level binders?
1933 -> [CallInstance] -- Instantiated call insts for binders
1934 -> [Id] -- New binders
1935 -> CoreBinding -- Unprocessed
1936 -> SpecM (Maybe CoreBinding, -- Instantiated version of input
1938 [Maybe SpecInfo] -- One for each id in the original binding
1941 mkOneInst do_cis@(CallInstance _ spec_tys dict_args _ _) explicit_cis
1942 no_of_dicts_to_specialise top_lev inst_cis new_ids orig_bind
1943 = newSpecIds new_ids spec_tys no_of_dicts_to_specialise
1944 `thenSM` \ spec_ids ->
1945 newTyVars (length [() | Nothing <- spec_tys]) `thenSM` \ poly_tyvars ->
1947 -- arg_tys is spec_tys with tyvars instead of the Nothing spec_tys
1948 -- which correspond to unspeciailsed args
1950 (_,arg_tys) = mapAccumL do_the_wotsit poly_tyvars spec_tys
1953 args = map TyArg arg_tys ++ dict_args
1955 (new_id:_) = new_ids
1956 (spec_id:_) = spec_ids
1958 do_bind (NonRec orig_id rhs)
1959 = do_one_rhs (spec_id, new_id, (orig_id,rhs))
1960 `thenSM` \ (maybe_spec, rhs_uds, spec_info) ->
1962 Just (spec_id, rhs) -> returnSM (Just (NonRec spec_id rhs), rhs_uds, [spec_info])
1963 Nothing -> returnSM (Nothing, rhs_uds, [spec_info])
1966 = mapAndUnzip3SM do_one_rhs (zip3 spec_ids new_ids pairs)
1967 `thenSM` \ (maybe_pairs, rhss_uds_s, spec_infos) ->
1968 returnSM (Just (Rec (catMaybes maybe_pairs)),
1969 unionUDList rhss_uds_s, spec_infos)
1971 do_one_rhs (spec_id, new_id, (orig_id, orig_rhs))
1973 -- Avoid duplicating a spec which has already been created ...
1974 -- This can arise in a Rec involving a dfun for which a
1975 -- a specialised instance has been created but specialisation
1976 -- "required" by one of the other Ids in the Rec
1977 | top_lev && maybeToBool lookup_orig_spec
1978 = (if opt_SpecialiseTrace
1979 then trace_nospec " Exists: " exists_id
1982 returnSM (Nothing, emptyUDs, Nothing)
1985 -- Check for a (single) explicit call instance for this id
1986 | not (null explicit_cis_for_this_id)
1987 = ASSERT (length explicit_cis_for_this_id == 1)
1988 (if opt_SpecialiseTrace
1989 then trace_nospec " Explicit: " explicit_id
1992 returnSM (Nothing, tickSpecInsts emptyUDs, Just explicit_spec_info)
1995 -- Apply the specialiser to (orig_rhs t1 a t3 d1 d2)
1997 = ASSERT (no_of_dicts_to_specialise == length dict_args)
1998 specExpr orig_rhs args `thenSM` \ (inst_rhs, inst_uds) ->
2000 -- For a local binding we dump the usage details, creating
2001 -- any local dict bindings required
2002 -- At the top-level the uds will be dumped in specBindAndScope
2003 -- and the dict bindings made *global*
2005 (local_dict_binds, final_uds)
2006 = if not top_lev then
2007 dumpUDs inst_uds False False inst_cis new_ids []
2011 spec_info = Just (SpecInfo spec_tys no_of_dicts_to_specialise spec_id)
2013 if isUnboxedType (idType spec_id) then
2014 ASSERT (null poly_tyvars)
2015 liftId spec_id `thenSM` \ (lift_spec_id, unlift_spec_id) ->
2016 mkTyConInstance liftDataCon [idType unlift_spec_id]
2017 `thenSM` \ lift_uds ->
2018 returnSM (Just (lift_spec_id,
2019 mkCoLetsNoUnboxed local_dict_binds (liftExpr unlift_spec_id inst_rhs)),
2020 tickSpecInsts (final_uds `unionUDs` lift_uds), spec_info)
2022 returnSM (Just (spec_id,
2023 mkCoLetsNoUnboxed local_dict_binds (mkTyLam poly_tyvars inst_rhs)),
2024 tickSpecInsts final_uds, spec_info)
2026 lookup_orig_spec = lookupSpecEnv (getIdSpecialisation orig_id) arg_tys
2027 Just (exists_id, _, _) = lookup_orig_spec
2029 explicit_cis_for_this_id = filter (isCIofTheseIds [new_id]) explicit_cis
2030 [CallInstance _ _ _ _ (Just explicit_spec_info)] = explicit_cis_for_this_id
2031 SpecInfo _ _ explicit_id = explicit_spec_info
2033 trace_nospec :: String -> Id -> a -> a
2034 trace_nospec str spec_id
2036 (ppCat [ppr PprDebug new_id, ppInterleave ppNil (map pp_ty arg_tys),
2037 ppStr "==>", ppr PprDebug spec_id])
2039 (if opt_SpecialiseTrace then
2040 pprTrace "Specialising:"
2041 (ppHang (ppBesides [ppStr "{",
2042 interppSP PprDebug new_ids,
2045 ppBesides [ppStr "types: ", ppInterleave ppNil (map pp_ty arg_tys)],
2046 if isExplicitCI do_cis then ppNil else
2047 ppBesides [ppStr "dicts: ", ppInterleave ppNil (map pp_dict dict_args)],
2048 ppBesides [ppStr "specs: ", ppr PprDebug spec_ids]]))
2051 do_bind orig_bind `thenSM` \ (maybe_inst_bind, inst_uds, spec_infos) ->
2053 returnSM (maybe_inst_bind, inst_uds, spec_infos)
2056 pp_dict d = ppr_arg PprDebug d
2057 pp_ty t = pprParendGenType PprDebug t
2059 do_the_wotsit (tyvar:tyvars) Nothing = (tyvars, mkTyVarTy tyvar)
2060 do_the_wotsit tyvars (Just ty) = (tyvars, ty)
2064 %************************************************************************
2066 \subsection[Misc]{Miscellaneous junk}
2068 %************************************************************************
2071 mkCallInstance :: Id
2073 -> [(CoreArg, UsageDetails, CoreExpr -> CoreExpr)]
2074 -> SpecM UsageDetails
2076 mkCallInstance id new_id []
2079 mkCallInstance id new_id args
2081 -- No specialised versions for "error" and friends are req'd.
2082 -- This is a special case in core lint etc.
2087 -- No call instances for SuperDictSelIds
2088 -- These are a special case in mkCall
2090 | maybeToBool (isSuperDictSelId_maybe id)
2093 -- There are also no call instances for ClassOpIds
2094 -- However, we need to process it to get any second-level call
2095 -- instances for a ConstMethodId extracted from its SpecEnv
2099 spec_overloading = opt_SpecialiseOverloaded
2100 spec_unboxed = opt_SpecialiseUnboxed
2101 spec_all = opt_SpecialiseAll
2103 (tyvars, class_tyvar_pairs) = getIdOverloading id
2105 arg_res = take_type_args tyvars class_tyvar_pairs args
2106 enough_args = maybeToBool arg_res
2108 (Just (tys, dicts, rest_args)) = arg_res
2111 = (record, lookup, spec_tys)
2113 spec_tys = specialiseCallTys spec_all spec_unboxed spec_overloading
2114 (mkConstraintVector id) tys
2116 record = any (not . isTyVarTy) (catMaybes spec_tys)
2118 lookup = lookupSpecEnv (getIdSpecialisation id) tys
2120 if (not enough_args) then
2121 pprPanic "Specialise:recordCallInst: Unsaturated Type & Dict Application:\n\t"
2122 (ppCat (ppr PprDebug id : map (ppr_arg PprDebug) [arg | (arg,_,_) <- args]))
2124 case record_spec id tys of
2126 -> -- pprTrace "CallInst:NotReqd\n"
2127 -- (ppCat [ppr PprDebug id, ppCat (map (ppr PprDebug) args)])
2130 (True, Nothing, spec_tys)
2131 -> if isClassOpId id then -- No CIs for class ops, dfun will give SPEC inst
2134 -- pprTrace "CallInst:Reqd\n"
2135 -- (ppAboves [ppCat [ppr PprDebug id, ppCat (map (ppr PprDebug) args)],
2136 -- ppCat [ppStr "CI", ppCat (map (pprMaybeTy PprDebug) spec_tys),
2137 -- ppCat (map (ppr PprDebug) dicts)]])
2138 (returnSM (singleCI new_id spec_tys dicts))
2140 (True, Just (spec_id, tys_left, toss), _)
2141 -> if maybeToBool (isConstMethodId_maybe spec_id) then
2142 -- If we got a const method spec_id see if further spec required
2143 -- NB: const method is top-level so spec_id will not be cloned
2144 case record_spec spec_id tys_left of
2146 -> -- pprTrace "CallInst:Exists\n"
2147 -- (ppAboves [ppCat [ppr PprDebug id, ppCat (map (ppr PprDebug) args)],
2148 -- ppCat [ppStr "->", ppr PprDebug spec_id,
2149 -- ppr PprDebug (tys_left ++ drop toss dicts)]])
2152 (True, Nothing, spec_tys)
2153 -> -- pprTrace "CallInst:Exists:Reqd\n"
2154 -- (ppAboves [ppCat [ppr PprDebug id, ppCat (map (ppr PprDebug) args)],
2155 -- ppCat [ppStr "->", ppr PprDebug spec_id,
2156 -- ppr PprDebug (tys_left ++ drop toss dicts)],
2157 -- ppCat [ppStr "CI", ppCat (map (pprMaybeTy PprDebug) spec_tys),
2158 -- ppCat (map (ppr PprDebug) (drop toss dicts))]])
2159 (returnSM (singleCI spec_id spec_tys (drop toss dicts)))
2161 (True, Just (spec_spec_id, tys_left_left, toss_toss), _)
2162 -> -- pprTrace "CallInst:Exists:Exists\n"
2163 -- (ppAboves [ppCat [ppr PprDebug id, ppCat (map (ppr PprDebug) args)],
2164 -- ppCat [ppStr "->", ppr PprDebug spec_id,
2165 -- ppr PprDebug (tys_left ++ drop toss dicts)],
2166 -- ppCat [ppStr "->", ppr PprDebug spec_spec_id,
2167 -- ppr PprDebug (tys_left_left ++ drop (toss + toss_toss) dicts)]])
2171 -- pprTrace "CallInst:Exists\n"
2172 -- (ppAboves [ppCat [ppr PprDebug id, ppCat (map (ppr PprDebug) args)],
2173 -- ppCat [ppStr "->", ppr PprDebug spec_id,
2174 -- ppr PprDebug (tys_left ++ drop toss dicts)]])
2178 take_type_args (_:tyvars) class_tyvar_pairs ((TyArg ty,_,_):args)
2179 = case (take_type_args tyvars class_tyvar_pairs args) of
2181 Just (tys, dicts, others) -> Just (ty:tys, dicts, others)
2183 take_type_args (_:tyvars) class_tyvar_pairs [] = Nothing
2185 take_type_args [] class_tyvar_pairs args
2186 = case (take_dict_args class_tyvar_pairs args) of
2188 Just (dicts, others) -> Just ([], dicts, others)
2190 take_dict_args (_:class_tyvar_pairs) ((dict,_,_):args) | isValArg dict
2191 = case (take_dict_args class_tyvar_pairs args) of
2193 Just (dicts, others) -> Just (dict:dicts, others)
2195 take_dict_args (_:class_tyvar_pairs) [] = Nothing
2197 take_dict_args [] args = Just ([], args)
2202 -> [(CoreArg, UsageDetails, CoreExpr -> CoreExpr)]
2203 -> SpecM (Bool, CoreExpr)
2206 | maybeToBool (isSuperDictSelId_maybe new_id)
2207 && any isUnboxedType ty_args
2208 -- No specialisations for super-dict selectors
2209 -- Specialise unboxed calls to SuperDictSelIds by extracting
2210 -- the super class dictionary directly form the super class
2211 -- NB: This should be dead code since all uses of this dictionary should
2212 -- have been specialised. We only do this to keep core-lint happy.
2214 Just (_, super_class) = isSuperDictSelId_maybe new_id
2215 super_dict_id = case lookupClassInstAtSimpleType super_class (head ty_args) of
2216 Nothing -> panic "Specialise:mkCall:SuperDictId"
2219 returnSM (False, Var super_dict_id)
2222 = case lookupSpecEnv (getIdSpecialisation new_id) ty_args of
2223 Nothing -> checkUnspecOK new_id ty_args (
2224 returnSM (False, unspec_call)
2227 Just spec_1_details@(spec_id_1, tys_left_1, dicts_to_toss_1)
2229 -- It may be necessary to specialsie a constant method spec_id again
2230 (spec_id, tys_left, dicts_to_toss) =
2231 case (maybeToBool (isConstMethodId_maybe spec_id_1),
2232 lookupSpecEnv (getIdSpecialisation spec_id_1) tys_left_1) of
2233 (False, _ ) -> spec_1_details
2234 (True, Nothing) -> spec_1_details
2235 (True, Just (spec_id_2, tys_left_2, dicts_to_toss_2))
2236 -> (spec_id_2, tys_left_2, dicts_to_toss_1 + dicts_to_toss_2)
2238 args_left = toss_dicts dicts_to_toss val_args
2240 checkSpecOK new_id ty_args spec_id tys_left (
2242 -- The resulting spec_id may be a top-level unboxed value
2243 -- This can arise for:
2244 -- 1) constant method values
2245 -- eq: class Num a where pi :: a
2246 -- instance Num Double# where pi = 3.141#
2247 -- 2) specilised overloaded values
2248 -- eq: i1 :: Num a => a
2249 -- i1 Int# d.Num.Int# ==> i1.Int#
2250 -- These top level defns should have been lifted.
2251 -- We must add code to unlift such a spec_id.
2253 if isUnboxedType (idType spec_id) then
2254 ASSERT (null tys_left && null args_left)
2255 if toplevelishId spec_id then
2256 liftId spec_id `thenSM` \ (lift_spec_id, unlift_spec_id) ->
2257 returnSM (True, bindUnlift lift_spec_id unlift_spec_id
2258 (Var unlift_spec_id))
2260 pprPanic "Specialise:mkCall: unboxed spec_id not top-level ...\n"
2261 (ppCat [ppr PprDebug new_id,
2262 ppInterleave ppNil (map (pprParendGenType PprDebug) ty_args),
2264 ppr PprDebug spec_id])
2267 (vals_left, _, unlifts_left) = unzip3 args_left
2268 applied_tys = mkTyApp (Var spec_id) tys_left
2269 applied_vals = mkGenApp applied_tys vals_left
2271 returnSM (True, applyBindUnlifts unlifts_left applied_vals)
2274 (tys_and_vals, _, unlifts) = unzip3 args
2275 unspec_call = applyBindUnlifts unlifts (mkGenApp (Var new_id) tys_and_vals)
2278 -- ty_args is the types at the front of the arg list
2279 -- val_args is the rest of the arg-list
2281 (ty_args, val_args) = get args
2283 get ((TyArg ty,_,_) : args) = (ty : tys, rest) where (tys,rest) = get args
2284 get args = ([], args)
2287 -- toss_dicts chucks away dict args, checking that they ain't types!
2288 toss_dicts 0 args = args
2289 toss_dicts n ((a,_,_) : args)
2290 | isValArg a = toss_dicts (n-1) args
2295 checkUnspecOK :: Id -> [Type] -> a -> a
2296 checkUnspecOK check_id tys
2297 = if isLocallyDefined check_id && any isUnboxedType tys
2298 then pprPanic "Specialise:checkUnspecOK: unboxed instance for local id not found\n"
2299 (ppCat [ppr PprDebug check_id,
2300 ppInterleave ppNil (map (pprParendGenType PprDebug) tys)])
2303 checkSpecOK :: Id -> [Type] -> Id -> [Type] -> a -> a
2304 checkSpecOK check_id tys spec_id tys_left
2305 = if any isUnboxedType tys_left
2306 then pprPanic "Specialise:checkSpecOK: unboxed type args in specialised application\n"
2307 (ppAboves [ppCat [ppr PprDebug check_id,
2308 ppInterleave ppNil (map (pprParendGenType PprDebug) tys)],
2309 ppCat [ppr PprDebug spec_id,
2310 ppInterleave ppNil (map (pprParendGenType PprDebug) tys_left)]])
2315 mkTyConInstance :: Id
2317 -> SpecM UsageDetails
2318 mkTyConInstance con tys
2319 = recordTyConInst con tys `thenSM` \ record_inst ->
2321 Nothing -- No TyCon instance
2322 -> -- pprTrace "NoTyConInst:"
2323 -- (ppCat [ppr PprDebug tycon, ppStr "at",
2324 -- ppr PprDebug con, ppCat (map (ppr PprDebug) tys)])
2325 (returnSM (singleConUDs con))
2327 Just spec_tys -- Record TyCon instance
2328 -> -- pprTrace "TyConInst:"
2329 -- (ppCat [ppr PprDebug tycon, ppStr "at",
2330 -- ppr PprDebug con, ppCat (map (ppr PprDebug) tys),
2331 -- ppBesides [ppStr "(",
2332 -- ppCat [pprMaybeTy PprDebug ty | ty <- spec_tys],
2334 (returnSM (singleTyConI tycon spec_tys `unionUDs` singleConUDs con))
2336 tycon = dataConTyCon con
2340 recordTyConInst :: Id
2342 -> SpecM (Maybe [Maybe Type])
2344 recordTyConInst con tys
2346 spec_tys = specialiseConstrTys tys
2348 do_tycon_spec = maybeToBool (firstJust spec_tys)
2350 spec_exists = maybeToBool (lookupSpecEnv
2351 (getIdSpecialisation con)
2354 -- pprTrace "ConSpecExists?: "
2355 -- (ppAboves [ppStr (if spec_exists then "True" else "False"),
2356 -- ppr PprShowAll con, ppCat (map (ppr PprDebug) tys)])
2357 (if (not spec_exists && do_tycon_spec)
2358 then returnSM (Just spec_tys)
2359 else returnSM Nothing)
2362 %************************************************************************
2364 \subsection[monad-Specialise]{Monad used in specialisation}
2366 %************************************************************************
2370 inherited: control flags and
2371 recordInst functions with flags cached
2373 environment mapping tyvars to types
2374 environment mapping Ids to Atoms
2376 threaded in and out: unique supply
2379 type TypeEnv = TyVarEnv Type
2388 = m nullTyVarEnv nullIdEnv uniqs
2390 returnSM :: a -> SpecM a
2391 thenSM :: SpecM a -> (a -> SpecM b) -> SpecM b
2392 fixSM :: (a -> SpecM a) -> SpecM a
2394 thenSM m k tvenv idenv us
2395 = case splitUniqSupply us of { (s1, s2) ->
2396 case (m tvenv idenv s1) of { r ->
2397 k r tvenv idenv s2 }}
2399 returnSM r tvenv idenv us = r
2401 fixSM k tvenv idenv us
2404 r = k r tvenv idenv us -- Recursive in r!
2407 The only interesting bit is figuring out the type of the SpecId!
2410 newSpecIds :: [Id] -- The id of which to make a specialised version
2411 -> [Maybe Type] -- Specialise to these types
2412 -> Int -- No of dicts to specialise
2415 newSpecIds new_ids maybe_tys dicts_to_ignore tvenv idenv us
2416 = [ mkSpecId uniq id maybe_tys (spec_id_ty id) (selectIdInfoForSpecId id)
2417 | (id,uniq) <- new_ids `zip` uniqs ]
2419 uniqs = getUniques (length new_ids) us
2420 spec_id_ty id = specialiseTy (idType id) maybe_tys dicts_to_ignore
2422 newTyVars :: Int -> SpecM [TyVar]
2423 newTyVars n tvenv idenv us
2424 = map mkPolySysTyVar uniqs
2426 uniqs = getUniques n us
2429 @cloneLambdaOrCaseBinders@ and @cloneLetBinders@ take a bunch of
2430 binders, and build ``clones'' for them. The clones differ from the
2431 originals in three ways:
2433 (a) they have a fresh unique
2434 (b) they have the current type environment applied to their type
2435 (c) for Let binders which have been specialised to unboxed values
2436 the clone will have a lifted type
2438 As well as returning the list of cloned @Id@s they also return a list of
2439 @CloneInfo@s which the original binders should be bound to.
2442 cloneLambdaOrCaseBinders :: [Id] -- Old binders
2443 -> SpecM ([Id], [CloneInfo]) -- New ones
2445 cloneLambdaOrCaseBinders old_ids tvenv idenv us
2447 uniqs = getUniques (length old_ids) us
2449 unzip (zipWithEqual clone_it old_ids uniqs)
2451 clone_it old_id uniq
2452 = (new_id, NoLift (VarArg new_id))
2454 new_id = applyTypeEnvToId tvenv (mkIdWithNewUniq old_id uniq)
2456 cloneLetBinders :: Bool -- Top level ?
2457 -> Bool -- Recursice
2458 -> [Id] -- Old binders
2459 -> SpecM ([Id], [CloneInfo]) -- New ones
2461 cloneLetBinders top_lev is_rec old_ids tvenv idenv us
2463 uniqs = getUniques (2 * length old_ids) us
2465 unzip (clone_them old_ids uniqs)
2467 clone_them [] [] = []
2469 clone_them (old_id:olds) (u1:u2:uniqs)
2472 NoLift (VarArg old_id)) : clone_rest
2474 -- Don't clone if it is a top-level thing. Why not?
2475 -- (a) we don't want to change the uniques
2476 -- on such things (see TopLevId in Id.lhs)
2477 -- (b) we don't have to be paranoid about name capture
2478 -- (c) the thing is polymorphic so no need to subst
2481 = if (is_rec && isUnboxedType new_ty && not (isUnboxedType old_ty))
2483 Lifted lifted_id unlifted_id) : clone_rest
2485 NoLift (VarArg new_id)) : clone_rest
2488 clone_rest = clone_them olds uniqs
2490 new_id = applyTypeEnvToId tvenv (mkIdWithNewUniq old_id u1)
2491 new_ty = idType new_id
2492 old_ty = idType old_id
2494 (lifted_id, unlifted_id) = mkLiftedId new_id u2
2497 cloneTyVarSM :: TyVar -> SpecM TyVar
2499 cloneTyVarSM old_tyvar tvenv idenv us
2503 cloneTyVar old_tyvar uniq -- new_tyvar
2505 bindId :: Id -> CloneInfo -> SpecM thing -> SpecM thing
2507 bindId id val specm tvenv idenv us
2508 = specm tvenv (addOneToIdEnv idenv id val) us
2510 bindIds :: [Id] -> [CloneInfo] -> SpecM thing -> SpecM thing
2512 bindIds olds news specm tvenv idenv us
2513 = specm tvenv (growIdEnvList idenv (zip olds news)) us
2515 bindSpecIds :: [Id] -- Old
2516 -> [(CloneInfo)] -- New
2517 -> [[Maybe SpecInfo]] -- Corresponding specialisations
2518 -- Each sub-list corresponds to a different type,
2519 -- and contains one Maybe spec_info for each id
2523 bindSpecIds olds clones spec_infos specm tvenv idenv us
2524 = specm tvenv (growIdEnvList idenv old_to_clone) us
2526 old_to_clone = mk_old_to_clone olds clones spec_infos
2528 -- The important thing here is that we are *lazy* in spec_infos
2529 mk_old_to_clone [] [] _ = []
2530 mk_old_to_clone (old:rest_olds) (clone:rest_clones) spec_infos
2531 = (old, add_spec_info clone) :
2532 mk_old_to_clone rest_olds rest_clones spec_infos_rest
2534 add_spec_info (NoLift (VarArg new))
2535 = NoLift (VarArg (new `addIdSpecialisation`
2536 (mkSpecEnv spec_infos_this_id)))
2537 add_spec_info lifted
2538 = lifted -- no specialised instances for unboxed lifted values
2540 spec_infos_this_id = catMaybes (map head spec_infos)
2541 spec_infos_rest = map tail spec_infos
2544 bindTyVar :: TyVar -> Type -> SpecM thing -> SpecM thing
2546 bindTyVar tyvar ty specm tvenv idenv us
2547 = specm (growTyVarEnvList tvenv [(tyvar,ty)]) idenv us
2551 lookupId :: Id -> SpecM CloneInfo
2553 lookupId id tvenv idenv us
2554 = case lookupIdEnv idenv id of
2555 Nothing -> NoLift (VarArg id)
2560 specTy :: Type -> SpecM Type -- Apply the current type envt to the type
2562 specTy ty tvenv idenv us
2563 = applyTypeEnvToTy tvenv ty
2567 liftId :: Id -> SpecM (Id, Id)
2568 liftId id tvenv idenv us
2575 In other monads these @mapSM@ things are usually called @listM@.
2576 I think @mapSM@ is a much better name. The `2' and `3' variants are
2577 when you want to return two or three results, and get at them
2578 separately. It saves you having to do an (unzip stuff) right after.
2581 mapSM :: (a -> SpecM b) -> [a] -> SpecM [b]
2582 mapAndUnzipSM :: (a -> SpecM (b1, b2)) -> [a] -> SpecM ([b1],[b2])
2583 mapAndUnzip3SM :: (a -> SpecM (b1, b2, b3)) -> [a] -> SpecM ([b1],[b2],[b3])
2584 mapAndUnzip4SM :: (a -> SpecM (b1, b2, b3, b4)) -> [a] -> SpecM ([b1],[b2],[b3],[b4])
2586 mapSM f [] = returnSM []
2587 mapSM f (x:xs) = f x `thenSM` \ r ->
2588 mapSM f xs `thenSM` \ rs ->
2591 mapAndUnzipSM f [] = returnSM ([],[])
2592 mapAndUnzipSM f (x:xs) = f x `thenSM` \ (r1, r2) ->
2593 mapAndUnzipSM f xs `thenSM` \ (rs1,rs2) ->
2594 returnSM ((r1:rs1),(r2:rs2))
2596 mapAndUnzip3SM f [] = returnSM ([],[],[])
2597 mapAndUnzip3SM f (x:xs) = f x `thenSM` \ (r1,r2,r3) ->
2598 mapAndUnzip3SM f xs `thenSM` \ (rs1,rs2,rs3) ->
2599 returnSM ((r1:rs1),(r2:rs2),(r3:rs3))
2601 mapAndUnzip4SM f [] = returnSM ([],[],[],[])
2602 mapAndUnzip4SM f (x:xs) = f x `thenSM` \ (r1,r2,r3,r4) ->
2603 mapAndUnzip4SM f xs `thenSM` \ (rs1,rs2,rs3,rs4) ->
2604 returnSM ((r1:rs1),(r2:rs2),(r3:rs3),(r4:rs4))