\begin{code}
module CoreSyn (
- Expr(..), Alt, Bind(..), Arg(..), Note(..),
+ Expr(..), Alt, Bind(..), AltCon(..), Arg, Note(..),
CoreExpr, CoreAlt, CoreBind, CoreArg, CoreBndr,
TaggedExpr, TaggedAlt, TaggedBind, TaggedArg,
- mkLets, mkLetBinds, mkLams,
- mkApps, mkTyApps, mkValApps,
- mkLit, mkStringLit, mkConApp, mkPrimApp, mkNote, mkNilExpr,
- bindNonRec, mkIfThenElse, varToCoreExpr,
+ mkLets, mkLams,
+ mkApps, mkTyApps, mkValApps, mkVarApps,
+ mkLit, mkIntLitInt, mkIntLit,
+ mkStringLit, mkStringLitFS, mkConApp,
+ varToCoreExpr,
- bindersOf, rhssOfBind, rhssOfAlts, isDeadBinder, isTyVar, isId,
+ bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts, isTyVar, isId,
collectBinders, collectTyBinders, collectValBinders, collectTyAndValBinders,
- collectArgs,
+ collectArgs, collectBindersIgnoringNotes,
coreExprCc,
+ flattenBinds,
- isValArg, isTypeArg, valArgCount,
+ isValArg, isTypeArg, valArgCount, valBndrCount,
+
+ -- Unfoldings
+ Unfolding(..), UnfoldingGuidance(..), -- Both abstract everywhere but in CoreUnfold.lhs
+ noUnfolding, mkOtherCon,
+ unfoldingTemplate, maybeUnfoldingTemplate, otherCons,
+ isValueUnfolding, isEvaldUnfolding, isCheapUnfolding, isCompulsoryUnfolding,
+ hasUnfolding, hasSomeUnfolding,
+
+ -- Seq stuff
+ seqRules, seqExpr, seqExprs, seqUnfolding,
-- Annotated expressions
- AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt, deAnnotate
+ AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt, deAnnotate, deAnnotate',
+
+ -- Core rules
+ CoreRules(..), -- Representation needed by friends
+ CoreRule(..), -- CoreSubst, CoreTidy, CoreFVs, PprCore only
+ RuleName,
+ emptyCoreRules, isEmptyCoreRules, rulesRhsFreeVars, rulesRules
) where
#include "HsVersions.h"
-import TysWiredIn ( boolTy, stringTy, nilDataCon )
-import CostCentre ( CostCentre, isDupdCC, noCostCentre )
-import Var ( Var, Id, TyVar, IdOrTyVar, isTyVar, isId, idType )
-import Id ( mkWildId, getInlinePragma )
-import Type ( Type, UsageAnn, mkTyVarTy, isUnLiftedType )
-import IdInfo ( InlinePragInfo(..) )
-import Const ( Con(..), DataCon, Literal(NoRepStr), PrimOp )
-import TysWiredIn ( trueDataCon, falseDataCon )
+import CostCentre ( CostCentre, noCostCentre )
+import Var ( Var, Id, TyVar, isTyVar, isId, idType )
+import VarEnv
+import Type ( Type, UsageAnn, mkTyVarTy, isUnLiftedType, seqType )
+import Literal ( Literal(MachStr), mkMachInt )
+import PrimOp ( PrimOp )
+import DataCon ( DataCon, dataConId )
+import ThinAir ( unpackCStringId, unpackCString2Id )
+import VarSet
import Outputable
\end{code}
These data types are the heart of the compiler
\begin{code}
+infixl 8 `App` -- App brackets to the left
+
data Expr b -- "b" for the type of binders,
= Var Id
- | Con Con [Arg b] -- Guaranteed saturated
- -- The Con can be a DataCon, Literal, PrimOP
- -- but cannot be DEFAULT
+ | Lit Literal
| App (Expr b) (Arg b)
| Lam b (Expr b)
| Let (Bind b) (Expr b)
type Arg b = Expr b -- Can be a Type
-type Alt b = (Con, [b], Expr b)
- -- (DEFAULT, [], rhs) is the default alternative
- -- The Con can be a Literal, DataCon, or DEFAULT, but cannot be PrimOp
+type Alt b = (AltCon, [b], Expr b) -- (DEFAULT, [], rhs) is the default alternative
+
+data AltCon = DataAlt DataCon
+ | LitAlt Literal
+ | DEFAULT
+ deriving (Eq, Ord)
data Bind b = NonRec b (Expr b)
| Rec [(b, (Expr b))]
| InlineCall -- Instructs simplifier to inline
-- the enclosed call
+ | InlineMe -- Instructs simplifer to treat the enclosed expression
+ -- as very small, and inline it at its call sites
+
| TermUsg -- A term-level usage annotation
UsageAnn -- (should not be a variable except during UsageSP inference)
\end{code}
%************************************************************************
%* *
+\subsection{Transformation rules}
+%* *
+%************************************************************************
+
+The CoreRule type and its friends are dealt with mainly in CoreRules,
+but CoreFVs, Subst, PprCore, CoreTidy also inspect the representation.
+
+\begin{code}
+data CoreRules
+ = Rules [CoreRule]
+ VarSet -- Locally-defined free vars of RHSs
+
+type RuleName = FAST_STRING
+
+data CoreRule
+ = Rule RuleName
+ [CoreBndr] -- Forall'd variables
+ [CoreExpr] -- LHS args
+ CoreExpr -- RHS
+
+ | BuiltinRule -- Built-in rules are used for constant folding
+ -- and suchlike. It has no free variables.
+ ([CoreExpr] -> Maybe (RuleName, CoreExpr))
+
+emptyCoreRules :: CoreRules
+emptyCoreRules = Rules [] emptyVarSet
+
+isEmptyCoreRules :: CoreRules -> Bool
+isEmptyCoreRules (Rules rs _) = null rs
+
+rulesRhsFreeVars :: CoreRules -> VarSet
+rulesRhsFreeVars (Rules _ fvs) = fvs
+
+rulesRules :: CoreRules -> [CoreRule]
+rulesRules (Rules rules _) = rules
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{@Unfolding@ type}
+%* *
+%************************************************************************
+
+The @Unfolding@ type is declared here to avoid numerous loops, but it
+should be abstract everywhere except in CoreUnfold.lhs
+
+\begin{code}
+data Unfolding
+ = NoUnfolding
+
+ | OtherCon [AltCon] -- It ain't one of these
+ -- (OtherCon xs) also indicates that something has been evaluated
+ -- and hence there's no point in re-evaluating it.
+ -- OtherCon [] is used even for non-data-type values
+ -- to indicated evaluated-ness. Notably:
+ -- data C = C !(Int -> Int)
+ -- case x of { C f -> ... }
+ -- Here, f gets an OtherCon [] unfolding.
+
+ | CompulsoryUnfolding CoreExpr -- There is no "original" definition,
+ -- so you'd better unfold.
+
+ | CoreUnfolding -- An unfolding with redundant cached information
+ CoreExpr -- Template; binder-info is correct
+ Bool -- This is a top-level binding
+ Bool -- exprIsCheap template (cached); it won't duplicate (much) work
+ -- if you inline this in more than one place
+ Bool -- exprIsValue template (cached); it is ok to discard a `seq` on
+ -- this variable
+ Bool -- exprIsBottom template (cached)
+ UnfoldingGuidance -- Tells about the *size* of the template.
+
+
+data UnfoldingGuidance
+ = UnfoldNever
+ | UnfoldIfGoodArgs Int -- and "n" value args
+
+ [Int] -- Discount if the argument is evaluated.
+ -- (i.e., a simplification will definitely
+ -- be possible). One elt of the list per *value* arg.
+
+ Int -- The "size" of the unfolding; to be elaborated
+ -- later. ToDo
+
+ Int -- Scrutinee discount: the discount to substract if the thing is in
+ -- a context (case (thing args) of ...),
+ -- (where there are the right number of arguments.)
+
+noUnfolding = NoUnfolding
+mkOtherCon = OtherCon
+
+seqUnfolding :: Unfolding -> ()
+seqUnfolding (CoreUnfolding e top b1 b2 b3 g)
+ = seqExpr e `seq` top `seq` b1 `seq` b2 `seq` b3 `seq` seqGuidance g
+seqUnfolding other = ()
+
+seqGuidance (UnfoldIfGoodArgs n ns a b) = n `seq` sum ns `seq` a `seq` b `seq` ()
+seqGuidance other = ()
+\end{code}
+
+\begin{code}
+unfoldingTemplate :: Unfolding -> CoreExpr
+unfoldingTemplate (CoreUnfolding expr _ _ _ _ _) = expr
+unfoldingTemplate (CompulsoryUnfolding expr) = expr
+unfoldingTemplate other = panic "getUnfoldingTemplate"
+
+maybeUnfoldingTemplate :: Unfolding -> Maybe CoreExpr
+maybeUnfoldingTemplate (CoreUnfolding expr _ _ _ _ _) = Just expr
+maybeUnfoldingTemplate (CompulsoryUnfolding expr) = Just expr
+maybeUnfoldingTemplate other = Nothing
+
+otherCons :: Unfolding -> [AltCon]
+otherCons (OtherCon cons) = cons
+otherCons other = []
+
+isValueUnfolding :: Unfolding -> Bool
+ -- Returns False for OtherCon
+isValueUnfolding (CoreUnfolding _ _ _ is_evald _ _) = is_evald
+isValueUnfolding other = False
+
+isEvaldUnfolding :: Unfolding -> Bool
+ -- Returns True for OtherCon
+isEvaldUnfolding (OtherCon _) = True
+isEvaldUnfolding (CoreUnfolding _ _ _ is_evald _ _) = is_evald
+isEvaldUnfolding other = False
+
+isCheapUnfolding :: Unfolding -> Bool
+isCheapUnfolding (CoreUnfolding _ _ is_cheap _ _ _) = is_cheap
+isCheapUnfolding other = False
+
+isCompulsoryUnfolding :: Unfolding -> Bool
+isCompulsoryUnfolding (CompulsoryUnfolding _) = True
+isCompulsoryUnfolding other = False
+
+hasUnfolding :: Unfolding -> Bool
+hasUnfolding (CoreUnfolding _ _ _ _ _ _) = True
+hasUnfolding (CompulsoryUnfolding _) = True
+hasUnfolding other = False
+
+hasSomeUnfolding :: Unfolding -> Bool
+hasSomeUnfolding NoUnfolding = False
+hasSomeUnfolding other = True
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{The main data type}
+%* *
+%************************************************************************
+
+\begin{code}
+-- The Ord is needed for the FiniteMap used in the lookForConstructor
+-- in SimplEnv. If you declared that lookForConstructor *ignores*
+-- constructor-applications with LitArg args, then you could get
+-- rid of this Ord.
+
+instance Outputable AltCon where
+ ppr (DataAlt dc) = ppr dc
+ ppr (LitAlt lit) = ppr lit
+ ppr DEFAULT = ptext SLIT("__DEFAULT")
+
+instance Show AltCon where
+ showsPrec p con = showsPrecSDoc p (ppr con)
+\end{code}
+
+
+%************************************************************************
+%* *
\subsection{Useful synonyms}
%* *
%************************************************************************
The common case
\begin{code}
-type CoreBndr = IdOrTyVar
+type CoreBndr = Var
type CoreExpr = Expr CoreBndr
type CoreArg = Arg CoreBndr
type CoreBind = Bind CoreBndr
mkApps :: Expr b -> [Arg b] -> Expr b
mkTyApps :: Expr b -> [Type] -> Expr b
mkValApps :: Expr b -> [Expr b] -> Expr b
+mkVarApps :: Expr b -> [Var] -> Expr b
mkApps f args = foldl App f args
mkTyApps f args = foldl (\ e a -> App e (Type a)) f args
mkValApps f args = foldl (\ e a -> App e a) f args
+mkVarApps f vars = foldl (\ e a -> App e (varToCoreExpr a)) f vars
-mkLit :: Literal -> Expr b
-mkStringLit :: String -> Expr b
-mkConApp :: DataCon -> [Arg b] -> Expr b
-mkPrimApp :: PrimOp -> [Arg b] -> Expr b
-
-mkLit lit = Con (Literal lit) []
-mkStringLit str = Con (Literal (NoRepStr (_PK_ str) stringTy)) []
-mkConApp con args = Con (DataCon con) args
-mkPrimApp op args = Con (PrimOp op) args
+mkLit :: Literal -> Expr b
+mkIntLit :: Integer -> Expr b
+mkIntLitInt :: Int -> Expr b
+mkStringLit :: String -> Expr b -- Makes a [Char] literal
+mkStringLitFS :: FAST_STRING -> Expr b -- Makes a [Char] literal
+mkConApp :: DataCon -> [Arg b] -> Expr b
+mkLets :: [Bind b] -> Expr b -> Expr b
+mkLams :: [b] -> Expr b -> Expr b
-mkNilExpr :: Type -> CoreExpr
-mkNilExpr ty = Con (DataCon nilDataCon) [Type ty]
+mkLit lit = Lit lit
+mkConApp con args = mkApps (Var (dataConId con)) args
-varToCoreExpr :: CoreBndr -> CoreExpr
-varToCoreExpr v | isId v = Var v
- | otherwise = Type (mkTyVarTy v)
-\end{code}
-
-\begin{code}
-mkLams :: [b] -> Expr b -> Expr b
mkLams binders body = foldr Lam body binders
-\end{code}
+mkLets binds body = foldr Let body binds
-\begin{code}
-mkLets :: [Bind b] -> Expr b -> Expr b
-mkLets binds body = foldr Let body binds
-
-mkLetBinds :: [CoreBind] -> CoreExpr -> CoreExpr
--- mkLetBinds is like mkLets, but it uses bindNonRec to
--- make a case binding for unlifted things
-mkLetBinds [] body = body
-mkLetBinds (NonRec b r : binds) body = bindNonRec b r (mkLetBinds binds body)
-mkLetBinds (bind : binds) body = Let bind (mkLetBinds binds body)
-
-bindNonRec :: Id -> CoreExpr -> CoreExpr -> CoreExpr
--- (bindNonRec x r b) produces either
--- let x = r in b
--- or
--- case r of x { _DEFAULT_ -> b }
---
--- depending on whether x is unlifted or not
-bindNonRec bndr rhs body
- | isUnLiftedType (idType bndr) = Case rhs bndr [(DEFAULT,[],body)]
- | otherwise = Let (NonRec bndr rhs) body
-
-mkIfThenElse :: CoreExpr -> CoreExpr -> CoreExpr -> CoreExpr
-mkIfThenElse guard then_expr else_expr
- = Case guard (mkWildId boolTy)
- [ (DataCon trueDataCon, [], then_expr),
- (DataCon falseDataCon, [], else_expr) ]
-\end{code}
-
-mkNote removes redundant coercions, and SCCs where possible
+mkIntLit n = Lit (mkMachInt n)
+mkIntLitInt n = Lit (mkMachInt (toInteger n))
-\begin{code}
-mkNote :: Note -> Expr b -> Expr b
-mkNote (Coerce to_ty1 from_ty1) (Note (Coerce to_ty2 from_ty2) expr)
- = ASSERT( from_ty1 == to_ty2 )
- mkNote (Coerce to_ty1 from_ty2) expr
+mkStringLit str = mkStringLitFS (_PK_ str)
-mkNote (SCC cc1) expr@(Note (SCC cc2) _)
- | isDupdCC cc1 -- Discard the outer SCC provided we don't need
- = expr -- to track its entry count
+mkStringLitFS str
+ | any is_NUL (_UNPK_ str)
+ = -- Must cater for NULs in literal string
+ mkApps (Var unpackCString2Id)
+ [Lit (MachStr str),
+ mkIntLitInt (_LENGTH_ str)]
-mkNote note@(SCC cc1) expr@(Lam x e) -- Move _scc_ inside lambda
- = Lam x (mkNote note e)
+ | otherwise
+ = -- No NULs in the string
+ App (Var unpackCStringId) (Lit (MachStr str))
--- Slide InlineCall in around the function
-mkNote InlineCall (App f a) = App (mkNote InlineCall f) a
-mkNote InlineCall (Var v) = Note InlineCall (Var v)
-mkNote InlineCall expr = expr
+ where
+ is_NUL c = c == '\0'
-mkNote note expr = Note note expr
+varToCoreExpr :: CoreBndr -> Expr b
+varToCoreExpr v | isId v = Var v
+ | otherwise = Type (mkTyVarTy v)
\end{code}
+
%************************************************************************
%* *
\subsection{Simple access functions}
bindersOf (NonRec binder _) = [binder]
bindersOf (Rec pairs) = [binder | (binder, _) <- pairs]
+bindersOfBinds :: [Bind b] -> [b]
+bindersOfBinds binds = foldr ((++) . bindersOf) [] binds
+
rhssOfBind :: Bind b -> [Expr b]
rhssOfBind (NonRec _ rhs) = [rhs]
rhssOfBind (Rec pairs) = [rhs | (_,rhs) <- pairs]
rhssOfAlts :: [Alt b] -> [Expr b]
rhssOfAlts alts = [e | (_,_,e) <- alts]
-isDeadBinder :: CoreBndr -> Bool
-isDeadBinder bndr | isId bndr = case getInlinePragma bndr of
- IAmDead -> True
- other -> False
- | otherwise = False -- TyVars count as not dead
+flattenBinds :: [Bind b] -> [(b, Expr b)] -- Get all the lhs/rhs pairs
+flattenBinds (NonRec b r : binds) = (b,r) : flattenBinds binds
+flattenBinds (Rec prs1 : binds) = prs1 ++ flattenBinds binds
+flattenBinds [] = []
\end{code}
We often want to strip off leading lambdas before getting down to
order.
\begin{code}
-collectBinders :: Expr b -> ([b], Expr b)
-collectTyBinders :: CoreExpr -> ([TyVar], CoreExpr)
-collectValBinders :: CoreExpr -> ([Id], CoreExpr)
-collectTyAndValBinders :: CoreExpr -> ([TyVar], [Id], CoreExpr)
+collectBinders :: Expr b -> ([b], Expr b)
+collectBindersIgnoringNotes :: Expr b -> ([b], Expr b)
+collectTyBinders :: CoreExpr -> ([TyVar], CoreExpr)
+collectValBinders :: CoreExpr -> ([Id], CoreExpr)
+collectTyAndValBinders :: CoreExpr -> ([TyVar], [Id], CoreExpr)
+
+collectBinders expr
+ = go [] expr
+ where
+ go bs (Lam b e) = go (b:bs) e
+ go bs e = (reverse bs, e)
+
+-- This one ignores notes. It's used in CoreUnfold and StrAnal
+-- when we aren't going to put the expression back together from
+-- the pieces, so we don't mind losing the Notes
+collectBindersIgnoringNotes expr
+ = go [] expr
+ where
+ go bs (Lam b e) = go (b:bs) e
+ go bs (Note _ e) = go bs e
+ go bs e = (reverse bs, e)
collectTyAndValBinders expr
= (tvs, ids, body)
(tvs, body1) = collectTyBinders expr
(ids, body) = collectValBinders body1
-collectBinders expr
- = go [] expr
- where
- go tvs (Lam b e) = go (b:tvs) e
- go tvs e = (reverse tvs, e)
-
collectTyBinders expr
= go [] expr
where
isTypeArg (Type _) = True
isTypeArg other = False
+valBndrCount :: [CoreBndr] -> Int
+valBndrCount [] = 0
+valBndrCount (b : bs) | isId b = 1 + valBndrCount bs
+ | otherwise = valBndrCount bs
+
valArgCount :: [Arg b] -> Int
valArgCount [] = 0
valArgCount (Type _ : args) = valArgCount args
%************************************************************************
%* *
+\subsection{Seq stuff}
+%* *
+%************************************************************************
+
+\begin{code}
+seqExpr :: CoreExpr -> ()
+seqExpr (Var v) = v `seq` ()
+seqExpr (Lit lit) = lit `seq` ()
+seqExpr (App f a) = seqExpr f `seq` seqExpr a
+seqExpr (Lam b e) = seqBndr b `seq` seqExpr e
+seqExpr (Let b e) = seqBind b `seq` seqExpr e
+seqExpr (Case e b as) = seqExpr e `seq` seqBndr b `seq` seqAlts as
+seqExpr (Note n e) = seqNote n `seq` seqExpr e
+seqExpr (Type t) = seqType t
+
+seqExprs [] = ()
+seqExprs (e:es) = seqExpr e `seq` seqExprs es
+
+seqNote (Coerce t1 t2) = seqType t1 `seq` seqType t2
+seqNote other = ()
+
+seqBndr b = b `seq` ()
+
+seqBndrs [] = ()
+seqBndrs (b:bs) = seqBndr b `seq` seqBndrs bs
+
+seqBind (NonRec b e) = seqBndr b `seq` seqExpr e
+seqBind (Rec prs) = seqPairs prs
+
+seqPairs [] = ()
+seqPairs ((b,e):prs) = seqBndr b `seq` seqExpr e `seq` seqPairs prs
+
+seqAlts [] = ()
+seqAlts ((c,bs,e):alts) = seqBndrs bs `seq` seqExpr e `seq` seqAlts alts
+
+seqRules :: CoreRules -> ()
+seqRules (Rules rules fvs) = seq_rules rules `seq` seqVarSet fvs
+
+seq_rules [] = ()
+seq_rules (Rule fs bs es e : rules) = seqBndrs bs `seq` seqExprs (e:es) `seq` seq_rules rules
+seq_rules (BuiltinRule _ : rules) = seq_rules rules
+\end{code}
+
+
+
+%************************************************************************
+%* *
\subsection{Annotated core; annotation at every node in the tree}
%* *
%************************************************************************
data AnnExpr' bndr annot
= AnnVar Id
- | AnnCon Con [AnnExpr bndr annot]
+ | AnnLit Literal
| AnnLam bndr (AnnExpr bndr annot)
| AnnApp (AnnExpr bndr annot) (AnnExpr bndr annot)
| AnnCase (AnnExpr bndr annot) bndr [AnnAlt bndr annot]
| AnnNote Note (AnnExpr bndr annot)
| AnnType Type
-type AnnAlt bndr annot = (Con, [bndr], AnnExpr bndr annot)
+type AnnAlt bndr annot = (AltCon, [bndr], AnnExpr bndr annot)
data AnnBind bndr annot
= AnnNonRec bndr (AnnExpr bndr annot)
\begin{code}
deAnnotate :: AnnExpr bndr annot -> Expr bndr
+deAnnotate (_, e) = deAnnotate' e
-deAnnotate (_, AnnType t) = Type t
-deAnnotate (_, AnnVar v) = Var v
-deAnnotate (_, AnnCon con args) = Con con (map deAnnotate args)
-deAnnotate (_, AnnLam binder body)= Lam binder (deAnnotate body)
-deAnnotate (_, AnnApp fun arg) = App (deAnnotate fun) (deAnnotate arg)
-deAnnotate (_, AnnNote note body) = Note note (deAnnotate body)
+deAnnotate' (AnnType t) = Type t
+deAnnotate' (AnnVar v) = Var v
+deAnnotate' (AnnLit lit) = Lit lit
+deAnnotate' (AnnLam binder body) = Lam binder (deAnnotate body)
+deAnnotate' (AnnApp fun arg) = App (deAnnotate fun) (deAnnotate arg)
+deAnnotate' (AnnNote note body) = Note note (deAnnotate body)
-deAnnotate (_, AnnLet bind body)
+deAnnotate' (AnnLet bind body)
= Let (deAnnBind bind) (deAnnotate body)
where
deAnnBind (AnnNonRec var rhs) = NonRec var (deAnnotate rhs)
deAnnBind (AnnRec pairs) = Rec [(v,deAnnotate rhs) | (v,rhs) <- pairs]
-deAnnotate (_, AnnCase scrut v alts)
+deAnnotate' (AnnCase scrut v alts)
= Case (deAnnotate scrut) v (map deAnnAlt alts)
where
deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs)