module CoreSyn (
Expr(..), Alt, Bind(..), AltCon(..), Arg, Note(..),
CoreExpr, CoreAlt, CoreBind, CoreArg, CoreBndr,
- TaggedExpr, TaggedAlt, TaggedBind, TaggedArg,
+ TaggedExpr, TaggedAlt, TaggedBind, TaggedArg, TaggedBndr(..),
mkLets, mkLams,
mkApps, mkTyApps, mkValApps, mkVarApps,
mkLit, mkIntLitInt, mkIntLit,
- mkStringLit, mkStringLitFS, mkConApp,
- mkAltExpr,
- bindNonRec, mkIfThenElse, varToCoreExpr,
+ mkConApp,
+ varToCoreExpr,
- bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts, isTyVar, isId,
+ isTyVar, isId,
+ bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts,
collectBinders, collectTyBinders, collectValBinders, collectTyAndValBinders,
- collectArgs, collectBindersIgnoringNotes,
+ collectArgs,
coreExprCc,
flattenBinds,
- isValArg, isTypeArg, valArgCount, valBndrCount,
+ isValArg, isTypeArg, valArgCount, valBndrCount, isRuntimeArg, isRuntimeVar,
- -- Seq stuff
- seqRules, seqExpr, seqExprs,
+ -- Unfoldings
+ Unfolding(..), UnfoldingGuidance(..), -- Both abstract everywhere but in CoreUnfold.lhs
+ noUnfolding, mkOtherCon,
+ unfoldingTemplate, maybeUnfoldingTemplate, otherCons,
+ isValueUnfolding, isEvaldUnfolding, isCheapUnfolding, isCompulsoryUnfolding,
+ hasUnfolding, hasSomeUnfolding, neverUnfold,
- -- Size
- coreBindsSize,
+ -- Seq stuff
+ seqRules, seqExpr, seqExprs, seqUnfolding,
-- Annotated expressions
- AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt, deAnnotate, deAnnotate',
+ AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt,
+ deAnnotate, deAnnotate', deAnnAlt, collectAnnBndrs,
-- Core rules
CoreRules(..), -- Representation needed by friends
CoreRule(..), -- CoreSubst, CoreTidy, CoreFVs, PprCore only
+ IdCoreRule,
RuleName,
- emptyCoreRules, isEmptyCoreRules, rulesRhsFreeVars, rulesRules
+ emptyCoreRules, isEmptyCoreRules, rulesRhsFreeVars, rulesRules,
+ isBuiltinRule, ruleName
) where
#include "HsVersions.h"
-import TysWiredIn ( boolTy, stringTy, nilDataCon )
+import CmdLineOpts ( opt_RuntimeTypes )
import CostCentre ( CostCentre, noCostCentre )
-import Var ( Var, Id, TyVar, isTyVar, isId, idType )
-import VarEnv
-import Id ( mkWildId, idOccInfo, idInfo )
-import Type ( Type, UsageAnn, mkTyVarTy, isUnLiftedType, seqType )
-import IdInfo ( OccInfo(..), megaSeqIdInfo )
-import Literal ( Literal(MachStr), mkMachInt )
-import PrimOp ( PrimOp )
-import DataCon ( DataCon, dataConId )
-import TysWiredIn ( trueDataCon, falseDataCon )
-import ThinAir ( unpackCStringId, unpackCString2Id, addr2IntegerId )
+import Var ( Var, Id, TyVar, isTyVar, isId )
+import Type ( Type, mkTyVarTy, seqType )
+import Literal ( Literal, mkMachInt )
+import DataCon ( DataCon, dataConWorkId )
+import BasicTypes ( Activation )
import VarSet
+import FastString
import Outputable
\end{code}
| Lam b (Expr b)
| Let (Bind b) (Expr b)
| Case (Expr b) b [Alt b] -- Binder gets bound to value of scrutinee
- -- DEFAULT case must be last, if it occurs at all
+ -- Invariant: the list of alternatives is ALWAYS EXHAUSTIVE
+ -- Invariant: the DEFAULT case must be *first*, if it occurs at all
| Note Note (Expr b)
| Type Type -- This should only show up at the top
-- level of an Arg
| 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)
+ | CoreNote String -- A generic core annotation, propagated but not used by GHC
+
+-- NOTE: we also treat expressions wrapped in InlineMe as
+-- 'cheap' and 'dupable' (in the sense of exprIsCheap, exprIsDupable)
+-- What this means is that we obediently inline even things that don't
+-- look like valuse. This is sometimes important:
+-- {-# INLINE f #-}
+-- f = g . h
+-- Here, f looks like a redex, and we aren't going to inline (.) because it's
+-- inside an INLINE, so it'll stay looking like a redex. Nevertheless, we
+-- should inline f even inside lambdas. In effect, we should trust the programmer.
\end{code}
+INVARIANTS:
+
+* The RHS of a letrec, and the RHSs of all top-level lets,
+ must be of LIFTED type.
+
+* The RHS of a let, may be of UNLIFTED type, but only if the expression
+ is ok-for-speculation. This means that the let can be floated around
+ without difficulty. e.g.
+ y::Int# = x +# 1# ok
+ y::Int# = fac 4# not ok [use case instead]
+
+* The argument of an App can be of any type.
+
+* The simplifier tries to ensure that if the RHS of a let is a constructor
+ application, its arguments are trivial, so that the constructor can be
+ inlined vigorously.
+
%************************************************************************
%* *
= Rules [CoreRule]
VarSet -- Locally-defined free vars of RHSs
-type RuleName = FAST_STRING
+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}
+
+\begin{code}
+type RuleName = FastString
+type IdCoreRule = (Id,CoreRule) -- Rules don't have their leading Id inside them
data CoreRule
= Rule RuleName
+ Activation -- When the rule is active
[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))
+ RuleName -- and suchlike. It has no free variables.
+ ([CoreExpr] -> Maybe CoreExpr)
-emptyCoreRules :: CoreRules
-emptyCoreRules = Rules [] emptyVarSet
+isBuiltinRule (BuiltinRule _ _) = True
+isBuiltinRule _ = False
-isEmptyCoreRules :: CoreRules -> Bool
-isEmptyCoreRules (Rules rs _) = null rs
+ruleName :: CoreRule -> RuleName
+ruleName (Rule n _ _ _ _) = n
+ruleName (BuiltinRule n _) = n
+\end{code}
-rulesRhsFreeVars :: CoreRules -> VarSet
-rulesRhsFreeVars (Rules _ fvs) = fvs
-rulesRules :: CoreRules -> [CoreRule]
-rulesRules (Rules rules _) = rules
+%************************************************************************
+%* *
+\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 -- True <=> top level binding
+ Bool -- exprIsValue template (cached); it is ok to discard a `seq` on
+ -- this variable
+ Bool -- True <=> doesn't waste (much) work to expand inside an inlining
+ -- Basically it's exprIsCheap
+ 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 g)
+ = seqExpr e `seq` top `seq` b1 `seq` b2 `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
+
+neverUnfold :: Unfolding -> Bool
+neverUnfold NoUnfolding = True
+neverUnfold (OtherCon _) = True
+neverUnfold (CoreUnfolding _ _ _ _ UnfoldNever) = True
+neverUnfold other = False
\end{code}
type CoreArg = Arg CoreBndr
type CoreBind = Bind CoreBndr
type CoreAlt = Alt CoreBndr
-type CoreNote = Note
\end{code}
Binders are ``tagged'' with a \tr{t}:
\begin{code}
-type Tagged t = (CoreBndr, t)
+data TaggedBndr t = TB CoreBndr t -- TB for "tagged binder"
+
+type TaggedBind t = Bind (TaggedBndr t)
+type TaggedExpr t = Expr (TaggedBndr t)
+type TaggedArg t = Arg (TaggedBndr t)
+type TaggedAlt t = Alt (TaggedBndr t)
+
+instance Outputable b => Outputable (TaggedBndr b) where
+ ppr (TB b l) = char '<' <> ppr b <> comma <> ppr l <> char '>'
-type TaggedBind t = Bind (Tagged t)
-type TaggedExpr t = Expr (Tagged t)
-type TaggedArg t = Arg (Tagged t)
-type TaggedAlt t = Alt (Tagged t)
+instance Outputable b => OutputableBndr (TaggedBndr b) where
+ pprBndr _ b = ppr b -- Simple
\end{code}
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
mkLit lit = Lit lit
-mkConApp con args = mkApps (Var (dataConId con)) args
+mkConApp con args = mkApps (Var (dataConWorkId con)) args
+
+mkLams binders body = foldr Lam body binders
+mkLets binds body = foldr Let body binds
mkIntLit n = Lit (mkMachInt n)
mkIntLitInt n = Lit (mkMachInt (toInteger n))
-mkStringLit str = mkStringLitFS (_PK_ str)
-
-mkStringLitFS str
- | any is_NUL (_UNPK_ str)
- = -- Must cater for NULs in literal string
- mkApps (Var unpackCString2Id)
- [Lit (MachStr str),
- mkIntLitInt (_LENGTH_ str)]
-
- | otherwise
- = -- No NULs in the string
- App (Var unpackCStringId) (Lit (MachStr str))
-
- where
- is_NUL c = c == '\0'
-
varToCoreExpr :: CoreBndr -> Expr b
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}
-
-\begin{code}
-mkLets :: [Bind b] -> Expr b -> Expr b
-mkLets binds body = foldr Let body binds
-
-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
--- It's used by the desugarer to avoid building bindings
--- that give Core Lint a heart attack. Actually the simplifier
--- deals with them perfectly well.
-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)
- [ (DataAlt trueDataCon, [], then_expr),
- (DataAlt falseDataCon, [], else_expr) ]
-\end{code}
-
-
-\begin{code}
-mkAltExpr :: AltCon -> [CoreBndr] -> [Type] -> CoreExpr
- -- This guy constructs the value that the scrutinee must have
- -- when you are in one particular branch of a case
-mkAltExpr (DataAlt con) args inst_tys
- = mkConApp con (map Type inst_tys ++ map varToCoreExpr args)
-mkAltExpr (LitAlt lit) [] []
- = Lit lit
-\end{code}
-
%************************************************************************
%* *
\begin{code}
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)
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)
where
\end{code}
+
%************************************************************************
%* *
\subsection{Predicates}
%* *
%************************************************************************
+@isRuntimeVar v@ returns if (Lam v _) really becomes a lambda at runtime,
+i.e. if type applications are actual lambdas because types are kept around
+at runtime.
+
+Similarly isRuntimeArg.
+
+\begin{code}
+isRuntimeVar :: Var -> Bool
+isRuntimeVar | opt_RuntimeTypes = \v -> True
+ | otherwise = \v -> isId v
+
+isRuntimeArg :: CoreExpr -> Bool
+isRuntimeArg | opt_RuntimeTypes = \e -> True
+ | otherwise = \e -> isValArg e
+\end{code}
+
\begin{code}
isValArg (Type _) = False
isValArg other = True
seqExprs (e:es) = seqExpr e `seq` seqExprs es
seqNote (Coerce t1 t2) = seqType t1 `seq` seqType t2
+seqNote (CoreNote s) = s `seq` ()
seqNote other = ()
seqBndr b = b `seq` ()
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
+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}
-\begin{code}
-coreBindsSize :: [CoreBind] -> Int
-coreBindsSize bs = foldr ((+) . bindSize) 0 bs
-
-exprSize :: CoreExpr -> Int
- -- A measure of the size of the expressions
- -- It also forces the expression pretty drastically as a side effect
-exprSize (Var v) = varSize v
-exprSize (Lit lit) = 1
-exprSize (App f a) = exprSize f + exprSize a
-exprSize (Lam b e) = varSize b + exprSize e
-exprSize (Let b e) = bindSize b + exprSize e
-exprSize (Case e b as) = exprSize e + varSize b + foldr ((+) . altSize) 0 as
-exprSize (Note n e) = exprSize e
-exprSize (Type t) = seqType t `seq`
- 1
-
-exprsSize = foldr ((+) . exprSize) 0
-
-varSize :: Var -> Int
-varSize b | isTyVar b = 1
- | otherwise = seqType (idType b) `seq`
- megaSeqIdInfo (idInfo b) `seq`
- 1
-
-varsSize = foldr ((+) . varSize) 0
-
-bindSize (NonRec b e) = varSize b + exprSize e
-bindSize (Rec prs) = foldr ((+) . pairSize) 0 prs
-
-pairSize (b,e) = varSize b + exprSize e
-
-altSize (c,bs,e) = c `seq` varsSize bs + exprSize e
-\end{code}
%************************************************************************
deAnnotate' (AnnCase scrut v alts)
= Case (deAnnotate scrut) v (map deAnnAlt alts)
- where
- deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs)
+
+deAnnAlt :: AnnAlt bndr annot -> Alt bndr
+deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs)
\end{code}
+\begin{code}
+collectAnnBndrs :: AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot)
+collectAnnBndrs e
+ = collect [] e
+ where
+ collect bs (_, AnnLam b body) = collect (b:bs) body
+ collect bs body = (reverse bs, body)
+\end{code}
projects / ghc-hetmet.git / blobdiff