clash-lib-1.8.2: src/Clash/Normalize.hs
{-|
Copyright : (C) 2012-2016, University of Twente,
2016 , Myrtle Software Ltd,
2017 , Google Inc.,
2021-2023, QBayLogic B.V.
License : BSD2 (see the file LICENSE)
Maintainer : QBayLogic B.V. <devops@qbaylogic.com>
Turn CoreHW terms into normalized CoreHW Terms
-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE TemplateHaskell #-}
module Clash.Normalize where
import Control.Exception (throw)
import qualified Control.Lens as Lens
import Control.Monad (when)
import Control.Monad.State.Strict (State)
import Data.Default (def)
import Data.Either (lefts,partitionEithers)
import qualified Data.IntMap as IntMap
import Data.List
(intersect, mapAccumL)
import qualified Data.Map as Map
import qualified Data.Maybe as Maybe
import qualified Data.Set as Set
import qualified Data.Set.Lens as Lens
#if MIN_VERSION_prettyprinter(1,7,0)
import Prettyprinter (vcat)
#else
import Data.Text.Prettyprint.Doc (vcat)
#endif
import GHC.BasicTypes.Extra (isNoInline)
import Clash.Annotations.BitRepresentation.Internal
(CustomReprs)
import Clash.Core.Evaluator.Types as WHNF (Evaluator)
import Clash.Core.FreeVars
(freeLocalIds, globalIds)
import Clash.Core.HasFreeVars (notElemFreeVars)
import Clash.Core.HasType
import Clash.Core.PartialEval as PE (Evaluator)
import Clash.Core.Pretty (PrettyOptions(..), showPpr, showPpr', ppr)
import Clash.Core.Subst
(extendGblSubstList, mkSubst, substTm)
import Clash.Core.Term (Term (..), collectArgsTicks
,mkApps, mkTicks)
import Clash.Core.Type (Type, splitCoreFunForallTy)
import Clash.Core.TyCon (TyConMap)
import Clash.Core.Type (isPolyTy)
import Clash.Core.Var (Id, varName, varType)
import Clash.Core.VarEnv
(VarEnv, elemVarSet, eltsVarEnv, emptyInScopeSet, emptyVarEnv,
extendVarEnv, lookupVarEnv, mapVarEnv, mapMaybeVarEnv,
mkVarEnv, mkVarSet, notElemVarEnv, notElemVarSet, nullVarEnv, unionVarEnv)
import Clash.Debug (traceIf)
import Clash.Driver.Types
(BindingMap, Binding(..), DebugOpts(..), ClashEnv(..))
import Clash.Netlist.Types
(HWMap, FilteredHWType(..))
import Clash.Netlist.Util
(splitNormalized)
import Clash.Normalize.Strategy
import Clash.Normalize.Transformations
import Clash.Normalize.Types
import Clash.Normalize.Util
import Clash.Rewrite.Combinators
((>->), (!->), bottomupR, repeatR, topdownR)
import Clash.Rewrite.Types
(RewriteEnv (..), RewriteState (..), bindings, debugOpts, extra,
tcCache, topEntities, newInlineStrategy)
import Clash.Rewrite.Util
(apply, isUntranslatableType, runRewriteSession)
import Clash.Util
import Clash.Util.Interpolate (i)
import Clash.Util.Supply (Supply)
import Data.Binary (encode)
import qualified Data.ByteString as BS
import qualified Data.ByteString.Lazy as BL
import System.IO.Unsafe (unsafePerformIO)
import Clash.Rewrite.Types (RewriteStep(..))
-- | Run a NormalizeSession in a given environment
runNormalization
:: ClashEnv
-> Supply
-- ^ UniqueSupply
-> BindingMap
-- ^ Global Binders
-> (CustomReprs -> TyConMap -> Type ->
State HWMap (Maybe (Either String FilteredHWType)))
-- ^ Hardcoded Type -> HWType translator
-> PE.Evaluator
-- ^ Hardcoded evaluator for partial evaluation
-> WHNF.Evaluator
-- ^ Hardcoded evaluator for WHNF (old evaluator)
-> VarEnv Bool
-- ^ Map telling whether a components is part of a recursive group
-> [Id]
-- ^ topEntities
-> NormalizeSession a
-- ^ NormalizeSession to run
-> IO a
runNormalization env supply globals typeTrans peEval eval rcsMap topEnts =
runRewriteSession rwEnv rwState
where
-- TODO The RewriteEnv should just take ClashOpts.
rwEnv = RewriteEnv
env
typeTrans
peEval
eval
(mkVarSet topEnts)
rwState = RewriteState
0
mempty -- transformCounters Map
globals
supply
(error $ $(curLoc) ++ "Report as bug: no curFun",noSrcSpan)
0
(IntMap.empty, 0)
emptyVarEnv
normState
normState = NormalizeState
emptyVarEnv
Map.empty
emptyVarEnv
emptyVarEnv
Map.empty
rcsMap
normalize
:: [Id]
-> NormalizeSession BindingMap
normalize [] = return emptyVarEnv
normalize top = do
(new,topNormalized) <- unzip <$> mapM normalize' top
newNormalized <- normalize (concat new)
return (unionVarEnv (mkVarEnv topNormalized) newNormalized)
normalize' :: Id -> NormalizeSession ([Id], (Id, Binding Term))
normalize' nm = do
exprM <- lookupVarEnv nm <$> Lens.use bindings
let nmS = showPpr (varName nm)
case exprM of
Just (Binding nm' sp inl pr tm r) -> do
tcm <- Lens.view tcCache
topEnts <- Lens.view topEntities
let isTop = nm `elemVarSet` topEnts
ty0 = coreTypeOf nm'
ty1 = if isTop then tvSubstWithTyEq ty0 else ty0
-- check for polymorphic types
when (isPolyTy ty1) $
let msg = $curLoc ++ [i|
Clash can only normalize monomorphic functions, but this is polymorphic:
#{showPpr' def{displayUniques=False\} nm'}
|]
msgExtra | ty0 == ty1 = Nothing
| otherwise = Just $ [i|
Even after applying type equality constraints it remained polymorphic:
#{showPpr' def{displayUniques=False\} nm'{varType=ty1\}}
|]
in throw (ClashException sp msg msgExtra)
-- check for unrepresentable result type
let (args,resTy) = splitCoreFunForallTy tcm ty1
isTopEnt = nm `elemVarSet` topEnts
isFunction = not $ null $ lefts args
resTyRep <- not <$> isUntranslatableType False resTy
if resTyRep
then do
tmNorm <- normalizeTopLvlBndr isTopEnt nm (Binding nm' sp inl pr tm r)
let usedBndrs = Lens.toListOf globalIds (bindingTerm tmNorm)
traceIf (bindingRecursive tmNorm)
(concat [ $(curLoc),"Expr belonging to bndr: ",nmS ," (:: "
, showPpr (coreTypeOf (bindingId tmNorm))
, ") remains recursive after normalization:\n"
, showPpr (bindingTerm tmNorm) ])
(return ())
prevNorm <- mapVarEnv bindingId <$> Lens.use (extra.normalized)
let toNormalize = filter (`notElemVarSet` topEnts)
$ filter (`notElemVarEnv` (extendVarEnv nm nm prevNorm)) usedBndrs
return (toNormalize,(nm,tmNorm))
else
do
-- Throw an error for unrepresentable topEntities and functions
when (isTopEnt || isFunction) $
let msg = $(curLoc) ++ [i|
This bndr has a non-representable return type and can't be normalized:
#{showPpr' def{displayUniques=False\} nm'}
|]
in throw (ClashException sp msg Nothing)
-- But allow the compilation to proceed for nonrepresentable values.
-- This can happen for example when GHC decides to create a toplevel binder
-- for the ByteArray# inside of a Natural constant.
-- (GHC-8.4 does this with tests/shouldwork/Numbers/Exp.hs)
-- It will later be inlined by flattenCallTree.
opts <- Lens.view debugOpts
traceIf (dbg_invariants opts)
(concat [$(curLoc), "Expr belonging to bndr: ", nmS, " (:: "
, showPpr (coreTypeOf nm')
, ") has a non-representable return type."
, " Not normalising:\n", showPpr tm] )
(return ([],(nm,(Binding nm' sp inl pr tm r))))
Nothing -> error $ $(curLoc) ++ "Expr belonging to bndr: " ++ nmS ++ " not found"
-- | Check whether the normalized bindings are non-recursive. Errors when one
-- of the components is recursive.
checkNonRecursive
:: BindingMap
-- ^ List of normalized binders
-> BindingMap
checkNonRecursive norm = case mapMaybeVarEnv go norm of
rcs | nullVarEnv rcs -> norm
rcs -> error $ $(curLoc) ++ "Callgraph after normalization contains following recursive components: "
++ show (vcat [ ppr a <> ppr b
| (a,b) <- eltsVarEnv rcs
])
where
go (Binding nm _ _ _ tm r) =
if r then Just (nm,tm) else Nothing
-- | Perform general \"clean up\" of the normalized (non-recursive) function
-- hierarchy. This includes:
--
-- * Inlining functions that simply \"wrap\" another function
cleanupGraph
:: Id
-> BindingMap
-> NormalizeSession BindingMap
cleanupGraph topEntity norm
| Just ct <- mkCallTree [] norm topEntity
= do ctFlat <- flattenCallTree ct
return (mkVarEnv $ snd $ callTreeToList [] ctFlat)
cleanupGraph _ norm = return norm
-- | A tree of identifiers and their bindings, with branches containing
-- additional bindings which are used. See "Clash.Driver.Types.Binding".
--
data CallTree
= CLeaf (Id, Binding Term)
| CBranch (Id, Binding Term) [CallTree]
mkCallTree
:: [Id]
-- ^ Visited
-> BindingMap
-- ^ Global binders
-> Id
-- ^ Root of the call graph
-> Maybe CallTree
mkCallTree visited bindingMap root
| Just rootTm <- lookupVarEnv root bindingMap
= let used = Set.toList $ Lens.setOf globalIds $ (bindingTerm rootTm)
other = Maybe.mapMaybe (mkCallTree (root:visited) bindingMap) (filter (`notElem` visited) used)
in case used of
[] -> Just (CLeaf (root,rootTm))
_ -> Just (CBranch (root,rootTm) other)
mkCallTree _ _ _ = Nothing
stripArgs
:: [Id]
-> [Id]
-> [Either Term Type]
-> Maybe [Either Term Type]
stripArgs _ (_:_) [] = Nothing
stripArgs allIds [] args = if any mentionsId args
then Nothing
else Just args
where
mentionsId t = not $ null (either (Lens.toListOf freeLocalIds) (const []) t
`intersect`
allIds)
stripArgs allIds (id_:ids) (Left (Var nm):args)
| id_ == nm = stripArgs allIds ids args
| otherwise = Nothing
stripArgs _ _ _ = Nothing
flattenNode
:: CallTree
-> NormalizeSession (Either CallTree ((Id,Term),[CallTree]))
flattenNode c@(CLeaf (_,(Binding _ _ spec _ _ _))) | isNoInline spec = return (Left c)
flattenNode c@(CLeaf (nm,(Binding _ _ _ _ e _))) = do
isTopEntity <- elemVarSet nm <$> Lens.view topEntities
if isTopEntity then return (Left c) else do
tcm <- Lens.view tcCache
let norm = splitNormalized tcm e
case norm of
Right (ids,[(bId,bExpr)],_) -> do
let (fun,args,ticks) = collectArgsTicks bExpr
case stripArgs ids (reverse ids) (reverse args) of
Just remainder | bId `notElemFreeVars` bExpr ->
return (Right ((nm,mkApps (mkTicks fun ticks) (reverse remainder)),[]))
_ -> return (Right ((nm,e),[]))
_ -> return (Right ((nm,e),[]))
flattenNode b@(CBranch (_,(Binding _ _ spec _ _ _)) _) | isNoInline spec =
return (Left b)
flattenNode b@(CBranch (nm,(Binding _ _ _ _ e _)) us) = do
isTopEntity <- elemVarSet nm <$> Lens.view topEntities
if isTopEntity then return (Left b) else do
tcm <- Lens.view tcCache
let norm = splitNormalized tcm e
case norm of
Right (ids,[(bId,bExpr)],_) -> do
let (fun,args,ticks) = collectArgsTicks bExpr
case stripArgs ids (reverse ids) (reverse args) of
Just remainder | bId `notElemFreeVars` bExpr ->
return (Right ((nm,mkApps (mkTicks fun ticks) (reverse remainder)),us))
_ -> return (Right ((nm,e),us))
_ -> do
newInlineStrat <- Lens.view newInlineStrategy
if newInlineStrat || isCheapFunction e
then return (Right ((nm,e),us))
else return (Left b)
flattenCallTree
:: CallTree
-> NormalizeSession CallTree
flattenCallTree c@(CLeaf _) = return c
flattenCallTree (CBranch (nm,(Binding nm' sp inl pr tm r)) used) = do
flattenedUsed <- mapM flattenCallTree used
(newUsed,il_ct) <- partitionEithers <$> mapM flattenNode flattenedUsed
let (toInline,il_used) = unzip il_ct
subst = extendGblSubstList (mkSubst emptyInScopeSet) toInline
newExpr <- case toInline of
[] -> return tm
_ -> do
let tm1 = substTm "flattenCallTree.flattenExpr" subst tm
-- NB: When -fclash-debug-history is on, emit binary data holding the recorded rewrite steps
opts <- Lens.view debugOpts
let rewriteHistFile = dbg_historyFile opts
when (Maybe.isJust rewriteHistFile) $
let !_ = unsafePerformIO
$ BS.appendFile (Maybe.fromJust rewriteHistFile)
$ BL.toStrict
$ encode RewriteStep
{ t_ctx = []
, t_name = "INLINE"
, t_bndrS = showPpr (varName nm')
, t_before = tm
, t_after = tm1
}
in pure ()
rewriteExpr ("flattenExpr",flatten) (showPpr nm, tm1) (nm', sp)
let allUsed = newUsed ++ concat il_used
-- inline all components when the resulting expression after flattening
-- is still considered "cheap". This happens often at the topEntity which
-- wraps another functions and has some selectors and data-constructors.
if not (isNoInline inl) && isCheapFunction newExpr
then do
let (toInline',allUsed') = unzip (map goCheap allUsed)
subst' = extendGblSubstList (mkSubst emptyInScopeSet)
(Maybe.catMaybes toInline')
let tm1 = substTm "flattenCallTree.flattenCheap" subst' newExpr
newExpr' <- rewriteExpr ("flattenCheap",flatten) (showPpr nm, tm1) (nm', sp)
return (CBranch (nm,(Binding nm' sp inl pr newExpr' r)) (concat allUsed'))
else return (CBranch (nm,(Binding nm' sp inl pr newExpr r)) allUsed)
where
flatten =
repeatR (topdownR (apply "appProp" appProp >->
apply "bindConstantVar" bindConstantVar >->
apply "caseCon" caseCon >->
(apply "reduceConst" reduceConst !-> apply "deadcode" deadCode) >->
apply "reduceNonRepPrim" reduceNonRepPrim >->
apply "removeUnusedExpr" removeUnusedExpr) >->
bottomupR (apply "flattenLet" flattenLet)) !->
topdownSucR (apply "topLet" topLet)
goCheap c@(CLeaf (nm2,(Binding _ _ inl2 _ e _)))
| isNoInline inl2 = (Nothing ,[c])
| otherwise = (Just (nm2,e),[])
goCheap c@(CBranch (nm2,(Binding _ _ inl2 _ e _)) us)
| isNoInline inl2 = (Nothing, [c])
| otherwise = (Just (nm2,e),us)
callTreeToList :: [Id] -> CallTree -> ([Id], [(Id, Binding Term)])
callTreeToList visited (CLeaf (nm,bndr))
| nm `elem` visited = (visited,[])
| otherwise = (nm:visited,[(nm,bndr)])
callTreeToList visited (CBranch (nm,bndr) used)
| nm `elem` visited = (visited,[])
| otherwise = (visited',(nm,bndr):(concat others))
where
(visited',others) = mapAccumL callTreeToList (nm:visited) used