1 {-# LANGUAGE PackageImports #-}
3 -- Functions to bring a Core expression in normal form. This module provides a
4 -- top level function "normalize", and defines the actual transformation passes that
7 module CLasH.Normalize (getNormalized, normalizeExpr, splitNormalized) where
11 import qualified Maybe
13 import qualified "transformers" Control.Monad.Trans as Trans
14 import qualified Control.Monad as Monad
15 import qualified Control.Monad.Trans.Writer as Writer
16 import qualified Data.Map as Map
17 import qualified Data.Monoid as Monoid
22 import qualified UniqSupply
23 import qualified CoreUtils
25 import qualified TcType
28 import qualified VarSet
29 import qualified NameSet
30 import qualified CoreFVs
31 import qualified CoreUtils
32 import qualified MkCore
33 import qualified HscTypes
34 import Outputable ( showSDoc, ppr, nest )
37 import CLasH.Normalize.NormalizeTypes
38 import CLasH.Translator.TranslatorTypes
39 import CLasH.Normalize.NormalizeTools
40 import CLasH.VHDL.VHDLTypes
41 import qualified CLasH.Utils as Utils
42 import CLasH.Utils.Core.CoreTools
43 import CLasH.Utils.Core.BinderTools
44 import CLasH.Utils.Pretty
46 --------------------------------
47 -- Start of transformations
48 --------------------------------
50 --------------------------------
52 --------------------------------
53 eta, etatop :: Transform
54 eta expr | is_fun expr && not (is_lam expr) = do
55 let arg_ty = (fst . Type.splitFunTy . CoreUtils.exprType) expr
56 id <- Trans.lift $ mkInternalVar "param" arg_ty
57 change (Lam id (App expr (Var id)))
58 -- Leave all other expressions unchanged
60 etatop = notappargs ("eta", eta)
62 --------------------------------
64 --------------------------------
65 beta, betatop :: Transform
66 -- Substitute arg for x in expr
67 beta (App (Lam x expr) arg) = change $ substitute [(x, arg)] expr
68 -- Propagate the application into the let
69 beta (App (Let binds expr) arg) = change $ Let binds (App expr arg)
70 -- Propagate the application into each of the alternatives
71 beta (App (Case scrut b ty alts) arg) = change $ Case scrut b ty' alts'
73 alts' = map (\(con, bndrs, expr) -> (con, bndrs, (App expr arg))) alts
74 ty' = CoreUtils.applyTypeToArg ty arg
75 -- Leave all other expressions unchanged
76 beta expr = return expr
77 -- Perform this transform everywhere
78 betatop = everywhere ("beta", beta)
80 --------------------------------
82 --------------------------------
83 -- Try to move casts as much downward as possible.
84 castprop, castproptop :: Transform
85 castprop (Cast (Let binds expr) ty) = change $ Let binds (Cast expr ty)
86 castprop expr@(Cast (Case scrut b _ alts) ty) = change (Case scrut b ty alts')
88 alts' = map (\(con, bndrs, expr) -> (con, bndrs, (Cast expr ty))) alts
89 -- Leave all other expressions unchanged
90 castprop expr = return expr
91 -- Perform this transform everywhere
92 castproptop = everywhere ("castprop", castprop)
94 --------------------------------
95 -- Cast simplification. Mostly useful for state packing and unpacking, but
96 -- perhaps for others as well.
97 --------------------------------
98 castsimpl, castsimpltop :: Transform
99 castsimpl expr@(Cast val ty) = do
100 -- Don't extract values that are already simpl
101 local_var <- Trans.lift $ is_local_var val
102 -- Don't extract values that are not representable, to prevent loops with
105 if (not local_var) && repr
107 -- Generate a binder for the expression
108 id <- Trans.lift $ mkBinderFor val "castval"
109 -- Extract the expression
110 change $ Let (NonRec id val) (Cast (Var id) ty)
113 -- Leave all other expressions unchanged
114 castsimpl expr = return expr
115 -- Perform this transform everywhere
116 castsimpltop = everywhere ("castsimpl", castsimpl)
119 --------------------------------
120 -- Lambda simplication
121 --------------------------------
122 -- Ensure that a lambda always evaluates to a let expressions or a simple
123 -- variable reference.
124 lambdasimpl, lambdasimpltop :: Transform
125 -- Don't simplify a lambda that evaluates to let, since this is already
126 -- normal form (and would cause infinite loops).
127 lambdasimpl expr@(Lam _ (Let _ _)) = return expr
128 -- Put the of a lambda in its own binding, but not when the expression is
129 -- already a local variable, or not representable (to prevent loops with
131 lambdasimpl expr@(Lam bndr res) = do
133 local_var <- Trans.lift $ is_local_var res
134 if not local_var && repr
136 id <- Trans.lift $ mkBinderFor res "res"
137 change $ Lam bndr (Let (NonRec id res) (Var id))
139 -- If the result is already a local var or not representable, don't
143 -- Leave all other expressions unchanged
144 lambdasimpl expr = return expr
145 -- Perform this transform everywhere
146 lambdasimpltop = everywhere ("lambdasimpl", lambdasimpl)
148 --------------------------------
149 -- let derecursification
150 --------------------------------
151 letderec, letderectop :: Transform
152 letderec expr@(Let (Rec binds) res) = case liftable of
153 -- Nothing is liftable, just return
155 -- Something can be lifted, generate a new let expression
156 _ -> change $ mkNonRecLets liftable (Let (Rec nonliftable) res)
158 -- Make a list of all the binders bound in this recursive let
159 bndrs = map fst binds
160 -- See which bindings are liftable
161 (liftable, nonliftable) = List.partition canlift binds
162 -- Any expression that does not use any of the binders in this recursive let
163 -- can be lifted into a nonrec let. It can't use its own binder either,
164 -- since that would mean the binding is self-recursive and should be in a
165 -- single bind recursive let.
166 canlift (bndr, e) = not $ expr_uses_binders bndrs e
167 -- Leave all other expressions unchanged
168 letderec expr = return expr
169 -- Perform this transform everywhere
170 letderectop = everywhere ("letderec", letderec)
172 --------------------------------
173 -- let simplification
174 --------------------------------
175 letsimpl, letsimpltop :: Transform
176 -- Don't simplify a let that evaluates to another let, since this is already
177 -- normal form (and would cause infinite loops with letflat below).
178 letsimpl expr@(Let _ (Let _ _)) = return expr
179 -- Put the "in ..." value of a let in its own binding, but not when the
180 -- expression is already a local variable, or not representable (to prevent loops with inlinenonrep).
181 letsimpl expr@(Let binds res) = do
183 local_var <- Trans.lift $ is_local_var res
184 if not local_var && repr
186 -- If the result is not a local var already (to prevent loops with
187 -- ourselves), extract it.
188 id <- Trans.lift $ mkBinderFor res "foo"
189 change $ Let binds (Let (NonRec id res) (Var id))
191 -- If the result is already a local var, don't extract it.
194 -- Leave all other expressions unchanged
195 letsimpl expr = return expr
196 -- Perform this transform everywhere
197 letsimpltop = everywhere ("letsimpl", letsimpl)
199 --------------------------------
201 --------------------------------
202 -- Takes a let that binds another let, and turns that into two nested lets.
204 -- let b = (let b' = expr' in res') in res
206 -- let b' = expr' in (let b = res' in res)
207 letflat, letflattop :: Transform
208 -- Turn a nonrec let that binds a let into two nested lets.
209 letflat (Let (NonRec b (Let binds res')) res) =
210 change $ Let binds (Let (NonRec b res') res)
211 letflat (Let (Rec binds) expr) = do
212 -- Flatten each binding.
213 binds' <- Utils.concatM $ Monad.mapM flatbind binds
214 -- Return the new let. We don't use change here, since possibly nothing has
215 -- changed. If anything has changed, flatbind has already flagged that
217 return $ Let (Rec binds') expr
219 -- Turns a binding of a let into a multiple bindings, or any other binding
220 -- into a list with just that binding
221 flatbind :: (CoreBndr, CoreExpr) -> TransformMonad [(CoreBndr, CoreExpr)]
222 flatbind (b, Let (Rec binds) expr) = change ((b, expr):binds)
223 flatbind (b, expr) = return [(b, expr)]
224 -- Leave all other expressions unchanged
225 letflat expr = return expr
226 -- Perform this transform everywhere
227 letflattop = everywhere ("letflat", letflat)
229 --------------------------------
231 --------------------------------
232 -- Remove empty (recursive) lets
233 letremove, letremovetop :: Transform
234 letremove (Let (Rec []) res) = change $ res
235 -- Leave all other expressions unchanged
236 letremove expr = return expr
237 -- Perform this transform everywhere
238 letremovetop = everywhere ("letremove", letremove)
240 --------------------------------
241 -- Simple let binding removal
242 --------------------------------
243 -- Remove a = b bindings from let expressions everywhere
244 letremovesimpletop :: Transform
245 letremovesimpletop = everywhere ("letremovesimple", inlinebind (\(b, e) -> Trans.lift $ is_local_var e))
247 --------------------------------
248 -- Unused let binding removal
249 --------------------------------
250 letremoveunused, letremoveunusedtop :: Transform
251 letremoveunused expr@(Let _ _) = do
252 -- Filter out all unused binds.
253 let binds' = filter dobind binds
254 -- Only set the changed flag if binds got removed
255 changeif (length binds' /= length binds) (mkNonRecLets binds' res)
257 (binds, res) = flattenLets expr
258 bound_exprs = map snd binds
259 -- For each bind check if the bind is used by res or any of the bound
261 dobind (bndr, _) = any (expr_uses_binders [bndr]) (res:bound_exprs)
262 -- Leave all other expressions unchanged
263 letremoveunused expr = return expr
264 letremoveunusedtop = everywhere ("letremoveunused", letremoveunused)
266 --------------------------------
267 -- Identical let binding merging
268 --------------------------------
269 -- Merge two bindings in a let if they are identical
270 -- TODO: We would very much like to use GHC's CSE module for this, but that
271 -- doesn't track if something changed or not, so we can't use it properly.
272 letmerge, letmergetop :: Transform
273 letmerge expr@(Let _ _) = do
274 let (binds, res) = flattenLets expr
275 binds' <- domerge binds
276 return $ mkNonRecLets binds' res
278 domerge :: [(CoreBndr, CoreExpr)] -> TransformMonad [(CoreBndr, CoreExpr)]
279 domerge [] = return []
281 es' <- mapM (mergebinds e) es
285 -- Uses the second bind to simplify the second bind, if applicable.
286 mergebinds :: (CoreBndr, CoreExpr) -> (CoreBndr, CoreExpr) -> TransformMonad (CoreBndr, CoreExpr)
287 mergebinds (b1, e1) (b2, e2)
288 -- Identical expressions? Replace the second binding with a reference to
290 | CoreUtils.cheapEqExpr e1 e2 = change $ (b2, Var b1)
291 -- Different expressions? Don't change
292 | otherwise = return (b2, e2)
293 -- Leave all other expressions unchanged
294 letmerge expr = return expr
295 letmergetop = everywhere ("letmerge", letmerge)
297 --------------------------------
299 --------------------------------
300 -- Remove a = B bindings, with B :: a -> b, or B :: forall x . T, from let
301 -- expressions everywhere. This means that any value that still needs to be
302 -- applied to something else (polymorphic values need to be applied to a
303 -- Type) will be inlined, and will eventually be applied to all their
306 -- This is a tricky function, which is prone to create loops in the
307 -- transformations. To fix this, we make sure that no transformation will
308 -- create a new let binding with a function type. These other transformations
309 -- will just not work on those function-typed values at first, but the other
310 -- transformations (in particular β-reduction) should make sure that the type
311 -- of those values eventually becomes primitive.
312 inlinenonreptop :: Transform
313 inlinenonreptop = everywhere ("inlinenonrep", inlinebind ((Monad.liftM not) . isRepr . snd))
315 --------------------------------
316 -- Scrutinee simplification
317 --------------------------------
318 scrutsimpl,scrutsimpltop :: Transform
319 -- Don't touch scrutinees that are already simple
320 scrutsimpl expr@(Case (Var _) _ _ _) = return expr
321 -- Replace all other cases with a let that binds the scrutinee and a new
322 -- simple scrutinee, but only when the scrutinee is representable (to prevent
323 -- loops with inlinenonrep, though I don't think a non-representable scrutinee
324 -- will be supported anyway...)
325 scrutsimpl expr@(Case scrut b ty alts) = do
329 id <- Trans.lift $ mkBinderFor scrut "scrut"
330 change $ Let (NonRec id scrut) (Case (Var id) b ty alts)
333 -- Leave all other expressions unchanged
334 scrutsimpl expr = return expr
335 -- Perform this transform everywhere
336 scrutsimpltop = everywhere ("scrutsimpl", scrutsimpl)
338 --------------------------------
339 -- Case binder wildening
340 --------------------------------
341 casesimpl, casesimpltop :: Transform
342 -- This is already a selector case (or, if x does not appear in bndrs, a very
343 -- simple case statement that will be removed by caseremove below). Just leave
345 casesimpl expr@(Case scrut b ty [(con, bndrs, Var x)]) = return expr
346 -- Make sure that all case alternatives have only wild binders and simple
348 -- This is done by creating a new let binding for each non-wild binder, which
349 -- is bound to a new simple selector case statement and for each complex
350 -- expression. We do this only for representable types, to prevent loops with
352 casesimpl expr@(Case scrut b ty alts) = do
353 (bindingss, alts') <- (Monad.liftM unzip) $ mapM doalt alts
354 let bindings = concat bindingss
355 -- Replace the case with a let with bindings and a case
356 let newlet = mkNonRecLets bindings (Case scrut b ty alts')
357 -- If there are no non-wild binders, or this case is already a simple
358 -- selector (i.e., a single alt with exactly one binding), already a simple
359 -- selector altan no bindings (i.e., no wild binders in the original case),
360 -- don't change anything, otherwise, replace the case.
361 if null bindings then return expr else change newlet
363 -- Generate a single wild binder, since they are all the same
364 wild = MkCore.mkWildBinder
365 -- Wilden the binders of one alt, producing a list of bindings as a
367 doalt :: CoreAlt -> TransformMonad ([(CoreBndr, CoreExpr)], CoreAlt)
368 doalt (con, bndrs, expr) = do
369 -- Make each binder wild, if possible
370 bndrs_res <- Monad.zipWithM dobndr bndrs [0..]
371 let (newbndrs, bindings_maybe) = unzip bndrs_res
372 -- Extract a complex expression, if possible. For this we check if any of
373 -- the new list of bndrs are used by expr. We can't use free_vars here,
374 -- since that looks at the old bndrs.
375 let uses_bndrs = not $ VarSet.isEmptyVarSet $ CoreFVs.exprSomeFreeVars (`elem` newbndrs) $ expr
376 (exprbinding_maybe, expr') <- doexpr expr uses_bndrs
377 -- Create a new alternative
378 let newalt = (con, newbndrs, expr')
379 let bindings = Maybe.catMaybes (bindings_maybe ++ [exprbinding_maybe])
380 return (bindings, newalt)
382 -- Make wild alternatives for each binder
383 wildbndrs = map (\bndr -> MkCore.mkWildBinder (Id.idType bndr)) bndrs
384 -- A set of all the binders that are used by the expression
385 free_vars = CoreFVs.exprSomeFreeVars (`elem` bndrs) expr
386 -- Look at the ith binder in the case alternative. Return a new binder
387 -- for it (either the same one, or a wild one) and optionally a let
388 -- binding containing a case expression.
389 dobndr :: CoreBndr -> Int -> TransformMonad (CoreBndr, Maybe (CoreBndr, CoreExpr))
391 repr <- isRepr (Var b)
392 -- Is b wild (e.g., not a free var of expr. Since b is only in scope
393 -- in expr, this means that b is unused if expr does not use it.)
394 let wild = not (VarSet.elemVarSet b free_vars)
395 -- Create a new binding for any representable binder that is not
396 -- already wild and is representable (to prevent loops with
398 if (not wild) && repr
400 -- Create on new binder that will actually capture a value in this
401 -- case statement, and return it.
402 let bty = (Id.idType b)
403 id <- Trans.lift $ mkInternalVar "sel" bty
404 let binders = take i wildbndrs ++ [id] ++ drop (i+1) wildbndrs
405 let caseexpr = Case scrut b bty [(con, binders, Var id)]
406 return (wildbndrs!!i, Just (b, caseexpr))
408 -- Just leave the original binder in place, and don't generate an
409 -- extra selector case.
411 -- Process the expression of a case alternative. Accepts an expression
412 -- and whether this expression uses any of the binders in the
413 -- alternative. Returns an optional new binding and a new expression.
414 doexpr :: CoreExpr -> Bool -> TransformMonad (Maybe (CoreBndr, CoreExpr), CoreExpr)
415 doexpr expr uses_bndrs = do
416 local_var <- Trans.lift $ is_local_var expr
418 -- Extract any expressions that do not use any binders from this
419 -- alternative, is not a local var already and is representable (to
420 -- prevent loops with inlinenonrep).
421 if (not uses_bndrs) && (not local_var) && repr
423 id <- Trans.lift $ mkBinderFor expr "caseval"
424 -- We don't flag a change here, since casevalsimpl will do that above
425 -- based on Just we return here.
426 return $ (Just (id, expr), Var id)
428 -- Don't simplify anything else
429 return (Nothing, expr)
430 -- Leave all other expressions unchanged
431 casesimpl expr = return expr
432 -- Perform this transform everywhere
433 casesimpltop = everywhere ("casesimpl", casesimpl)
435 --------------------------------
437 --------------------------------
438 -- Remove case statements that have only a single alternative and only wild
440 caseremove, caseremovetop :: Transform
441 -- Replace a useless case by the value of its single alternative
442 caseremove (Case scrut b ty [(con, bndrs, expr)]) | not usesvars = change expr
443 -- Find if any of the binders are used by expr
444 where usesvars = (not . VarSet.isEmptyVarSet . (CoreFVs.exprSomeFreeVars (`elem` bndrs))) expr
445 -- Leave all other expressions unchanged
446 caseremove expr = return expr
447 -- Perform this transform everywhere
448 caseremovetop = everywhere ("caseremove", caseremove)
450 --------------------------------
451 -- Argument extraction
452 --------------------------------
453 -- Make sure that all arguments of a representable type are simple variables.
454 appsimpl, appsimpltop :: Transform
455 -- Simplify all representable arguments. Do this by introducing a new Let
456 -- that binds the argument and passing the new binder in the application.
457 appsimpl expr@(App f arg) = do
458 -- Check runtime representability
460 local_var <- Trans.lift $ is_local_var arg
461 if repr && not local_var
462 then do -- Extract representable arguments
463 id <- Trans.lift $ mkBinderFor arg "arg"
464 change $ Let (NonRec id arg) (App f (Var id))
465 else -- Leave non-representable arguments unchanged
467 -- Leave all other expressions unchanged
468 appsimpl expr = return expr
469 -- Perform this transform everywhere
470 appsimpltop = everywhere ("appsimpl", appsimpl)
472 --------------------------------
473 -- Function-typed argument propagation
474 --------------------------------
475 -- Remove all applications to function-typed arguments, by duplication the
476 -- function called with the function-typed parameter replaced by the free
477 -- variables of the argument passed in.
478 argprop, argproptop :: Transform
479 -- Transform any application of a named function (i.e., skip applications of
480 -- lambda's). Also skip applications that have arguments with free type
481 -- variables, since we can't inline those.
482 argprop expr@(App _ _) | is_var fexpr = do
483 -- Find the body of the function called
484 body_maybe <- Trans.lift $ getGlobalBind f
487 -- Process each of the arguments in turn
488 (args', changed) <- Writer.listen $ mapM doarg args
489 -- See if any of the arguments changed
490 case Monoid.getAny changed of
492 let (newargs', newparams', oldargs) = unzip3 args'
493 let newargs = concat newargs'
494 let newparams = concat newparams'
495 -- Create a new body that consists of a lambda for all new arguments and
496 -- the old body applied to some arguments.
497 let newbody = MkCore.mkCoreLams newparams (MkCore.mkCoreApps body oldargs)
498 -- Create a new function with the same name but a new body
499 newf <- Trans.lift $ mkFunction f newbody
500 -- Replace the original application with one of the new function to the
502 change $ MkCore.mkCoreApps (Var newf) newargs
504 -- Don't change the expression if none of the arguments changed
507 -- If we don't have a body for the function called, leave it unchanged (it
508 -- should be a primitive function then).
509 Nothing -> return expr
511 -- Find the function called and the arguments
512 (fexpr, args) = collectArgs expr
515 -- Process a single argument and return (args, bndrs, arg), where args are
516 -- the arguments to replace the given argument in the original
517 -- application, bndrs are the binders to include in the top-level lambda
518 -- in the new function body, and arg is the argument to apply to the old
520 doarg :: CoreExpr -> TransformMonad ([CoreExpr], [CoreBndr], CoreExpr)
523 bndrs <- Trans.lift getGlobalBinders
524 let interesting var = Var.isLocalVar var && (not $ var `elem` bndrs)
525 if not repr && not (is_var arg && interesting (exprToVar arg)) && not (has_free_tyvars arg)
527 -- Propagate all complex arguments that are not representable, but not
528 -- arguments with free type variables (since those would require types
529 -- not known yet, which will always be known eventually).
530 -- Find interesting free variables, each of which should be passed to
531 -- the new function instead of the original function argument.
533 -- Interesting vars are those that are local, but not available from the
534 -- top level scope (functions from this module are defined as local, but
535 -- they're not local to this function, so we can freely move references
536 -- to them into another function).
537 let free_vars = VarSet.varSetElems $ CoreFVs.exprSomeFreeVars interesting arg
538 -- Mark the current expression as changed
540 return (map Var free_vars, free_vars, arg)
542 -- Representable types will not be propagated, and arguments with free
543 -- type variables will be propagated later.
544 -- TODO: preserve original naming?
545 id <- Trans.lift $ mkBinderFor arg "param"
546 -- Just pass the original argument to the new function, which binds it
547 -- to a new id and just pass that new id to the old function body.
548 return ([arg], [id], mkReferenceTo id)
549 -- Leave all other expressions unchanged
550 argprop expr = return expr
551 -- Perform this transform everywhere
552 argproptop = everywhere ("argprop", argprop)
554 --------------------------------
555 -- Function-typed argument extraction
556 --------------------------------
557 -- This transform takes any function-typed argument that cannot be propagated
558 -- (because the function that is applied to it is a builtin function), and
559 -- puts it in a brand new top level binder. This allows us to for example
560 -- apply map to a lambda expression This will not conflict with inlinenonrep,
561 -- since that only inlines local let bindings, not top level bindings.
562 funextract, funextracttop :: Transform
563 funextract expr@(App _ _) | is_var fexpr = do
564 body_maybe <- Trans.lift $ getGlobalBind f
566 -- We don't have a function body for f, so we can perform this transform.
568 -- Find the new arguments
569 args' <- mapM doarg args
570 -- And update the arguments. We use return instead of changed, so the
571 -- changed flag doesn't get set if none of the args got changed.
572 return $ MkCore.mkCoreApps fexpr args'
573 -- We have a function body for f, leave this application to funprop
574 Just _ -> return expr
576 -- Find the function called and the arguments
577 (fexpr, args) = collectArgs expr
579 -- Change any arguments that have a function type, but are not simple yet
580 -- (ie, a variable or application). This means to create a new function
581 -- for map (\f -> ...) b, but not for map (foo a) b.
583 -- We could use is_applicable here instead of is_fun, but I think
584 -- arguments to functions could only have forall typing when existential
585 -- typing is enabled. Not sure, though.
586 doarg arg | not (is_simple arg) && is_fun arg = do
587 -- Create a new top level binding that binds the argument. Its body will
588 -- be extended with lambda expressions, to take any free variables used
589 -- by the argument expression.
590 let free_vars = VarSet.varSetElems $ CoreFVs.exprFreeVars arg
591 let body = MkCore.mkCoreLams free_vars arg
592 id <- Trans.lift $ mkBinderFor body "fun"
593 Trans.lift $ addGlobalBind id body
594 -- Replace the argument with a reference to the new function, applied to
596 change $ MkCore.mkCoreApps (Var id) (map Var free_vars)
597 -- Leave all other arguments untouched
598 doarg arg = return arg
600 -- Leave all other expressions unchanged
601 funextract expr = return expr
602 -- Perform this transform everywhere
603 funextracttop = everywhere ("funextract", funextract)
605 --------------------------------
606 -- End of transformations
607 --------------------------------
612 -- What transforms to run?
613 transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letmergetop, letremoveunusedtop, castsimpltop, lambdasimpltop]
615 -- | Returns the normalized version of the given function.
617 CoreBndr -- ^ The function to get
618 -> TranslatorSession CoreExpr -- The normalized function body
620 getNormalized bndr = Utils.makeCached bndr tsNormalized $ do
621 if is_poly (Var bndr)
623 -- This should really only happen at the top level... TODO: Give
624 -- a different error if this happens down in the recursion.
625 error $ "\nNormalize.normalizeBind: Function " ++ show bndr ++ " is polymorphic, can't normalize"
627 expr <- getBinding bndr
628 normalizeExpr (show bndr) expr
630 -- | Normalize an expression
632 String -- ^ What are we normalizing? For debug output only.
633 -> CoreSyn.CoreExpr -- ^ The expression to normalize
634 -> TranslatorSession CoreSyn.CoreExpr -- ^ The normalized expression
636 normalizeExpr what expr = do
637 -- Normalize this expression
638 trace (what ++ " before normalization:\n\n" ++ showSDoc ( ppr expr ) ++ "\n") $ return ()
639 expr' <- dotransforms transforms expr
640 trace ("\n" ++ what ++ " after normalization:\n\n" ++ showSDoc ( ppr expr')) $ return ()
643 -- | Get the value that is bound to the given binder at top level. Fails when
644 -- there is no such binding.
646 CoreBndr -- ^ The binder to get the expression for
647 -> TranslatorSession CoreExpr -- ^ The value bound to the binder
649 getBinding bndr = Utils.makeCached bndr tsBindings $ do
650 -- If the binding isn't in the "cache" (bindings map), then we can't create
651 -- it out of thin air, so return an error.
652 error $ "Normalize.getBinding: Unknown function requested: " ++ show bndr
654 -- | Split a normalized expression into the argument binders, top level
655 -- bindings and the result binder.
657 CoreExpr -- ^ The normalized expression
658 -> ([CoreBndr], [Binding], CoreBndr)
659 splitNormalized expr = (args, binds, res)
661 (args, letexpr) = CoreSyn.collectBinders expr
662 (binds, resexpr) = flattenLets letexpr
663 res = case resexpr of
665 _ -> error $ "Normalize.splitNormalized: Not in normal form: " ++ pprString expr ++ "\n"