import qualified "transformers" Control.Monad.Trans as Trans
import qualified Control.Monad as Monad
import qualified Control.Monad.Trans.Writer as Writer
-import qualified Data.Map as Map
+import qualified Data.Accessor.Monad.Trans.State as MonadState
import qualified Data.Monoid as Monoid
-import Data.Accessor
+import qualified Data.Map as Map
-- GHC API
import CoreSyn
-import qualified UniqSupply
import qualified CoreUtils
import qualified Type
-import qualified TcType
-import qualified Name
import qualified Id
import qualified Var
+import qualified Name
import qualified VarSet
-import qualified NameSet
import qualified CoreFVs
-import qualified CoreUtils
+import qualified Class
import qualified MkCore
-import qualified HscTypes
import Outputable ( showSDoc, ppr, nest )
-- Local imports
import CLasH.Normalize.NormalizeTypes
import CLasH.Translator.TranslatorTypes
import CLasH.Normalize.NormalizeTools
-import CLasH.VHDL.VHDLTypes
+import CLasH.VHDL.Constants (builtinIds)
import qualified CLasH.Utils as Utils
import CLasH.Utils.Core.CoreTools
import CLasH.Utils.Core.BinderTools
--------------------------------
-- Remove empty (recursive) lets
letremove, letremovetop :: Transform
-letremove (Let (Rec []) res) = change $ res
+letremove (Let (Rec []) res) = change res
-- Leave all other expressions unchanged
letremove expr = return expr
-- Perform this transform everywhere
-- doesn't seem to set all those names as "system names", we apply some
-- guessing here.
inlinetoplevel, inlinetopleveltop :: Transform
+-- HACK: Don't inline == and /=. The default (derived) implementation
+-- for /= uses the polymorphic version of ==, which gets a dictionary
+-- for Eq passed in, which contains a reference to itself, resulting in
+-- an infinite loop in transformation. Not inlining == is really a hack,
+-- but for now it keeps things working with the most common symptom of
+-- this problem.
+inlinetoplevel expr@(Var f) | Name.getOccString f `elem` ["==", "/="] = return expr
-- Any system name is candidate for inlining. Never inline user-defined
-- functions, to preserve structure.
inlinetoplevel expr@(Var f) | not $ isUserDefined f = do
- norm <- isNormalizeable f
- -- See if this is a top level binding for which we have a body
- body_maybe <- Trans.lift $ getGlobalBind f
- if norm && Maybe.isJust body_maybe
- then do
- -- Get the normalized version
- norm <- Trans.lift $ getNormalized f
- if needsInline norm
- then do
- -- Regenerate all uniques in the to-be-inlined expression
- norm_uniqued <- Trans.lift $ genUniques norm
- change norm_uniqued
- else
- return expr
- else
- -- No body or not normalizeable.
- return expr
+ body_maybe <- needsInline f
+ case body_maybe of
+ Just body -> do
+ -- Regenerate all uniques in the to-be-inlined expression
+ body_uniqued <- Trans.lift $ genUniques body
+ -- And replace the variable reference with the unique'd body.
+ change body_uniqued
+ -- No need to inline
+ Nothing -> return expr
+
+
-- Leave all other expressions unchanged
inlinetoplevel expr = return expr
inlinetopleveltop = everywhere ("inlinetoplevel", inlinetoplevel)
+
+-- | Does the given binder need to be inlined? If so, return the body to
+-- be used for inlining.
+needsInline :: CoreBndr -> TransformMonad (Maybe CoreExpr)
+needsInline f = do
+ body_maybe <- Trans.lift $ getGlobalBind f
+ case body_maybe of
+ -- No body available?
+ Nothing -> return Nothing
+ Just body -> case CoreSyn.collectArgs body of
+ -- The body is some (top level) binder applied to 0 or more
+ -- arguments. That should be simple enough to inline.
+ (Var f, args) -> return $ Just body
+ -- Body is more complicated, try normalizing it
+ _ -> do
+ norm_maybe <- Trans.lift $ getNormalized_maybe f
+ case norm_maybe of
+ -- Noth normalizeable
+ Nothing -> return Nothing
+ Just norm -> case splitNormalized norm of
+ -- The function has just a single binding, so that's simple
+ -- enough to inline.
+ (args, [bind], res) -> return $ Just norm
+ -- More complicated function, don't inline
+ _ -> return Nothing
+
+--------------------------------
+-- Dictionary inlining
+--------------------------------
+-- Inline all top level dictionaries, so we can use them to resolve
+-- class methods based on the dictionary passed.
+inlinedict expr@(Var f) | Id.isDictId f = do
+ body_maybe <- Trans.lift $ getGlobalBind f
+ case body_maybe of
+ Nothing -> return expr
+ Just body -> change body
-needsInline :: CoreExpr -> Bool
-needsInline expr = case splitNormalized expr of
- -- Inline any function that only has a single definition, it is probably
- -- simple enough. This might inline some stuff that it shouldn't though it
- -- will never inline user-defined functions (inlinetoplevel only tries
- -- system names) and inlining should never break things.
- (args, [bind], res) -> True
- _ -> False
+-- Leave all other expressions unchanged
+inlinedict expr = return expr
+inlinedicttop = everywhere ("inlinedict", inlinedict)
+
+--------------------------------
+-- ClassOp resolution
+--------------------------------
+-- Resolves any class operation to the actual operation whenever
+-- possible. Class methods (as well as parent dictionary selectors) are
+-- special "functions" that take a type and a dictionary and evaluate to
+-- the corresponding method. A dictionary is nothing more than a
+-- special dataconstructor applied to the type the dictionary is for,
+-- each of the superclasses and all of the class method definitions for
+-- that particular type. Since dictionaries all always inlined (top
+-- levels dictionaries are inlined by inlinedict, local dictionaries are
+-- inlined by inlinenonrep), we will eventually have something like:
+--
+-- baz
+-- @ CLasH.HardwareTypes.Bit
+-- (D:Baz @ CLasH.HardwareTypes.Bit bitbaz)
+--
+-- Here, baz is the method selector for the baz method, while
+-- D:Baz is the dictionary constructor for the Baz and bitbaz is the baz
+-- method defined in the Baz Bit instance declaration.
+--
+-- To resolve this, we can look at the ClassOp IdInfo from the baz Id,
+-- which contains the Class it is defined for. From the Class, we can
+-- get a list of all selectors (both parent class selectors as well as
+-- method selectors). Since the arguments to D:Baz (after the type
+-- argument) correspond exactly to this list, we then look up baz in
+-- that list and replace the entire expression by the corresponding
+-- argument to D:Baz.
+--
+-- We don't resolve methods that have a builtin translation (such as
+-- ==), since the actual implementation is not always (easily)
+-- translateable. For example, when deriving ==, GHC generates code
+-- using $con2tag functions to translate a datacon to an int and compare
+-- that with GHC.Prim.==# . Better to avoid that for now.
+classopresolution, classopresolutiontop :: Transform
+classopresolution expr@(App (App (Var sel) ty) dict) | not is_builtin =
+ case Id.isClassOpId_maybe sel of
+ -- Not a class op selector
+ Nothing -> return expr
+ Just cls -> case collectArgs dict of
+ (_, []) -> return expr -- Dict is not an application (e.g., not inlined yet)
+ (Var dictdc, (ty':selectors)) | not (Maybe.isJust (Id.isDataConId_maybe dictdc)) -> return expr -- Dictionary is not a datacon yet (but e.g., a top level binder)
+ | tyargs_neq ty ty' -> error $ "Normalize.classopresolution: Applying class selector to dictionary without matching type?\n" ++ pprString expr
+ | otherwise ->
+ let selector_ids = Class.classSelIds cls in
+ -- Find the selector used in the class' list of selectors
+ case List.elemIndex sel selector_ids of
+ Nothing -> error $ "Normalize.classopresolution: Selector not found in class' selector list? This should not happen!\nExpression: " ++ pprString expr ++ "\nClass: " ++ show cls ++ "\nSelectors: " ++ show selector_ids
+ -- Get the corresponding argument from the dictionary
+ Just n -> change (selectors!!n)
+ (_, _) -> return expr -- Not applying a variable? Don't touch
+ where
+ -- Compare two type arguments, returning True if they are _not_
+ -- equal
+ tyargs_neq (Type ty1) (Type ty2) = not $ Type.coreEqType ty1 ty2
+ tyargs_neq _ _ = True
+ -- Is this a builtin function / method?
+ is_builtin = elem (Name.getOccString sel) builtinIds
+
+-- Leave all other expressions unchanged
+classopresolution expr = return expr
+-- Perform this transform everywhere
+classopresolutiontop = everywhere ("classopresolution", classopresolution)
--------------------------------
-- Scrutinee simplification
-- Perform this transform everywhere
scrutsimpltop = everywhere ("scrutsimpl", scrutsimpl)
+--------------------------------
+-- Scrutinee binder removal
+--------------------------------
+-- A case expression can have an extra binder, to which the scrutinee is bound
+-- after bringing it to WHNF. This is used for forcing evaluation of strict
+-- arguments. Since strictness does not matter for us (rather, everything is
+-- sort of strict), this binder is ignored when generating VHDL, and must thus
+-- be wild in the normal form.
+scrutbndrremove, scrutbndrremovetop :: Transform
+-- If the scrutinee is already simple, and the bndr is not wild yet, replace
+-- all occurences of the binder with the scrutinee variable.
+scrutbndrremove (Case (Var scrut) bndr ty alts) | bndr_used = do
+ alts' <- mapM subs_bndr alts
+ change $ Case (Var scrut) wild ty alts'
+ where
+ is_used (_, _, expr) = expr_uses_binders [bndr] expr
+ bndr_used = or $ map is_used alts
+ subs_bndr (con, bndrs, expr) = do
+ expr' <- substitute bndr (Var scrut) expr
+ return (con, bndrs, expr')
+ wild = MkCore.mkWildBinder (Id.idType bndr)
+-- Leave all other expressions unchanged
+scrutbndrremove expr = return expr
+scrutbndrremovetop = everywhere ("scrutbndrremove", scrutbndrremove)
+
--------------------------------
-- Case binder wildening
--------------------------------
-- is bound to a new simple selector case statement and for each complex
-- expression. We do this only for representable types, to prevent loops with
-- inlinenonrep.
-casesimpl expr@(Case scrut b ty alts) = do
+casesimpl expr@(Case scrut bndr ty alts) | not bndr_used = do
(bindingss, alts') <- (Monad.liftM unzip) $ mapM doalt alts
let bindings = concat bindingss
-- Replace the case with a let with bindings and a case
- let newlet = mkNonRecLets bindings (Case scrut b ty alts')
+ let newlet = mkNonRecLets bindings (Case scrut bndr ty alts')
-- If there are no non-wild binders, or this case is already a simple
-- selector (i.e., a single alt with exactly one binding), already a simple
-- selector altan no bindings (i.e., no wild binders in the original case),
-- don't change anything, otherwise, replace the case.
if null bindings then return expr else change newlet
where
+ -- Check if the scrutinee binder is used
+ is_used (_, _, expr) = expr_uses_binders [bndr] expr
+ bndr_used = or $ map is_used alts
-- Generate a single wild binder, since they are all the same
wild = MkCore.mkWildBinder
-- Wilden the binders of one alt, producing a list of bindings as a
-- Extract a complex expression, if possible. For this we check if any of
-- the new list of bndrs are used by expr. We can't use free_vars here,
-- since that looks at the old bndrs.
- let uses_bndrs = not $ VarSet.isEmptyVarSet $ CoreFVs.exprSomeFreeVars (`elem` newbndrs) $ expr
+ let uses_bndrs = not $ VarSet.isEmptyVarSet $ CoreFVs.exprSomeFreeVars (`elem` newbndrs) expr
(exprbinding_maybe, expr') <- doexpr expr uses_bndrs
-- Create a new alternative
let newalt = (con, newbndrs, expr')
id <- Trans.lift $ mkBinderFor expr "caseval"
-- We don't flag a change here, since casevalsimpl will do that above
-- based on Just we return here.
- return $ (Just (id, expr), Var id)
+ return (Just (id, expr), Var id)
else
-- Don't simplify anything else
return (Nothing, expr)
-- Replace a useless case by the value of its single alternative
caseremove (Case scrut b ty [(con, bndrs, expr)]) | not usesvars = change expr
-- Find if any of the binders are used by expr
- where usesvars = (not . VarSet.isEmptyVarSet . (CoreFVs.exprSomeFreeVars (`elem` bndrs))) expr
+ where usesvars = (not . VarSet.isEmptyVarSet . (CoreFVs.exprSomeFreeVars (`elem` b:bndrs))) expr
-- Leave all other expressions unchanged
caseremove expr = return expr
-- Perform this transform everywhere
let newbody = MkCore.mkCoreLams newparams (MkCore.mkCoreApps body oldargs)
-- Create a new function with the same name but a new body
newf <- Trans.lift $ mkFunction f newbody
+
+ Trans.lift $ MonadState.modify tsInitStates (\ismap ->
+ let init_state_maybe = Map.lookup f ismap in
+ case init_state_maybe of
+ Nothing -> ismap
+ Just init_state -> Map.insert newf init_state ismap)
-- Replace the original application with one of the new function to the
-- new arguments.
change $ MkCore.mkCoreApps (Var newf) newargs
doarg arg = do
repr <- isRepr arg
bndrs <- Trans.lift getGlobalBinders
- let interesting var = Var.isLocalVar var && (not $ var `elem` bndrs)
+ let interesting var = Var.isLocalVar var && (var `notElem` bndrs)
if not repr && not (is_var arg && interesting (exprToVar arg)) && not (has_free_tyvars arg)
then do
-- Propagate all complex arguments that are not representable, but not
let free_vars = VarSet.varSetElems $ CoreFVs.exprSomeFreeVars interesting arg
-- Mark the current expression as changed
setChanged
+ -- TODO: Clone the free_vars (and update references in arg), since
+ -- this might cause conflicts if two arguments that are propagated
+ -- share a free variable. Also, we are now introducing new variables
+ -- into a function that are not fresh, which violates the binder
+ -- uniqueness invariant.
return (map Var free_vars, free_vars, arg)
else do
-- Representable types will not be propagated, and arguments with free
-- type variables will be propagated later.
+ -- Note that we implicitly remove any type variables in the type of
+ -- the original argument by using the type of the actual argument
+ -- for the new formal parameter.
-- TODO: preserve original naming?
id <- Trans.lift $ mkBinderFor arg "param"
-- Just pass the original argument to the new function, which binds it
-- What transforms to run?
-transforms = [inlinetopleveltop, argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop, castsimpltop, lambdasimpltop, simplrestop]
+transforms = [inlinedicttop, inlinetopleveltop, classopresolutiontop, argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, scrutbndrremovetop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop, castsimpltop, lambdasimpltop, simplrestop]
--- | Returns the normalized version of the given function.
+-- | Returns the normalized version of the given function, or an error
+-- if it is not a known global binder.
getNormalized ::
CoreBndr -- ^ The function to get
-> TranslatorSession CoreExpr -- The normalized function body
-
-getNormalized bndr = Utils.makeCached bndr tsNormalized $ do
- if is_poly (Var bndr)
- then
- -- This should really only happen at the top level... TODO: Give
- -- a different error if this happens down in the recursion.
- error $ "\nNormalize.normalizeBind: Function " ++ show bndr ++ " is polymorphic, can't normalize"
- else do
- expr <- getBinding bndr
- normalizeExpr (show bndr) expr
+getNormalized bndr = do
+ norm <- getNormalized_maybe bndr
+ return $ Maybe.fromMaybe
+ (error $ "Normalize.getNormalized: Unknown or non-representable function requested: " ++ show bndr)
+ norm
+
+-- | Returns the normalized version of the given function, or Nothing
+-- when the binder is not a known global binder or is not normalizeable.
+getNormalized_maybe ::
+ CoreBndr -- ^ The function to get
+ -> TranslatorSession (Maybe CoreExpr) -- The normalized function body
+
+getNormalized_maybe bndr = do
+ expr_maybe <- getGlobalBind bndr
+ normalizeable <- isNormalizeable' bndr
+ if not normalizeable || Maybe.isNothing expr_maybe
+ then
+ -- Binder not normalizeable or not found
+ return Nothing
+ else if is_poly (Var bndr)
+ then
+ -- This should really only happen at the top level... TODO: Give
+ -- a different error if this happens down in the recursion.
+ error $ "\nNormalize.normalizeBind: Function " ++ show bndr ++ " is polymorphic, can't normalize"
+ else do
+ -- Binder found and is monomorphic. Normalize the expression
+ -- and cache the result.
+ normalized <- Utils.makeCached bndr tsNormalized $
+ normalizeExpr (show bndr) (Maybe.fromJust expr_maybe)
+ return (Just normalized)
-- | Normalize an expression
normalizeExpr ::
trace ("\n" ++ what ++ " after normalization:\n\n" ++ showSDoc ( ppr expr')) $ return ()
return expr'
--- | Get the value that is bound to the given binder at top level. Fails when
--- there is no such binding.
-getBinding ::
- CoreBndr -- ^ The binder to get the expression for
- -> TranslatorSession CoreExpr -- ^ The value bound to the binder
-
-getBinding bndr = Utils.makeCached bndr tsBindings $ do
- -- If the binding isn't in the "cache" (bindings map), then we can't create
- -- it out of thin air, so return an error.
- error $ "Normalize.getBinding: Unknown function requested: " ++ show bndr
-
-- | Split a normalized expression into the argument binders, top level
-- bindings and the result binder.
splitNormalized ::
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