%
% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1997-1998
%
\section[BasicTypes]{Miscellanous types}
This module defines a miscellaneously collection of very simple
types that
\begin{itemize}
\item have no other obvious home
\item don't depend on any other complicated types
\item are used in more than one "part" of the compiler
\end{itemize}
\begin{code}
module BasicTypes(
Version, bumpVersion, initialVersion,
Arity,
FunctionOrData(..),
WarningTxt(..),
Fixity(..), FixityDirection(..),
defaultFixity, maxPrecedence,
negateFixity, funTyFixity,
compareFixity,
IPName(..), ipNameName, mapIPName,
RecFlag(..), isRec, isNonRec, boolToRecFlag,
RuleName,
TopLevelFlag(..), isTopLevel, isNotTopLevel,
OverlapFlag(..),
Boxity(..), isBoxed,
TupCon(..), tupleParens,
OccInfo(..), seqOccInfo, zapFragileOcc, isOneOcc,
isDeadOcc, isLoopBreaker, isNonRuleLoopBreaker, isNoOcc,
nonRuleLoopBreaker,
InsideLam, insideLam, notInsideLam,
OneBranch, oneBranch, notOneBranch,
InterestingCxt,
EP(..),
HsBang(..), isBanged, isMarkedUnboxed,
StrictnessMark(..), isMarkedStrict,
DefMethSpec(..),
CompilerPhase(..), PhaseNum,
Activation(..), isActive, isActiveIn,
isNeverActive, isAlwaysActive, isEarlyActive,
RuleMatchInfo(..), isConLike, isFunLike,
InlineSpec(..),
InlinePragma(..), defaultInlinePragma, alwaysInlinePragma,
neverInlinePragma, dfunInlinePragma,
isDefaultInlinePragma,
isInlinePragma, isInlinablePragma, isAnyInlinePragma,
inlinePragmaSpec, inlinePragmaSat,
inlinePragmaActivation, inlinePragmaRuleMatchInfo,
setInlinePragmaActivation, setInlinePragmaRuleMatchInfo,
SuccessFlag(..), succeeded, failed, successIf
) where
import FastString
import Outputable
import Data.Data hiding (Fixity)
\end{code}
%************************************************************************
%* *
\subsection[Arity]{Arity}
%* *
%************************************************************************
\begin{code}
type Arity = Int
\end{code}
%************************************************************************
%* *
\subsection[FunctionOrData]{FunctionOrData}
%* *
%************************************************************************
\begin{code}
data FunctionOrData = IsFunction | IsData
deriving (Eq, Ord, Data, Typeable)
instance Outputable FunctionOrData where
ppr IsFunction = text "(function)"
ppr IsData = text "(data)"
\end{code}
%************************************************************************
%* *
\subsection[Version]{Module and identifier version numbers}
%* *
%************************************************************************
\begin{code}
type Version = Int
bumpVersion :: Version -> Version
bumpVersion v = v+1
initialVersion :: Version
initialVersion = 1
\end{code}
%************************************************************************
%* *
Deprecations
%* *
%************************************************************************
\begin{code}
data WarningTxt = WarningTxt [FastString]
| DeprecatedTxt [FastString]
deriving (Eq, Data, Typeable)
instance Outputable WarningTxt where
ppr (WarningTxt ws) = doubleQuotes (vcat (map ftext ws))
ppr (DeprecatedTxt ds) = text "Deprecated:" <+>
doubleQuotes (vcat (map ftext ds))
\end{code}
%************************************************************************
%* *
\subsection{Implicit parameter identity}
%* *
%************************************************************************
The @IPName@ type is here because it is used in TypeRep (i.e. very
early in the hierarchy), but also in HsSyn.
\begin{code}
newtype IPName name = IPName name
deriving( Eq, Ord, Data, Typeable )
ipNameName :: IPName name -> name
ipNameName (IPName n) = n
mapIPName :: (a->b) -> IPName a -> IPName b
mapIPName f (IPName n) = IPName (f n)
instance Outputable name => Outputable (IPName name) where
ppr (IPName n) = char '?' <> ppr n
\end{code}
%************************************************************************
%* *
Rules
%* *
%************************************************************************
\begin{code}
type RuleName = FastString
\end{code}
%************************************************************************
%* *
\subsection[Fixity]{Fixity info}
%* *
%************************************************************************
\begin{code}
data Fixity = Fixity Int FixityDirection
deriving (Data, Typeable)
instance Outputable Fixity where
ppr (Fixity prec dir) = hcat [ppr dir, space, int prec]
instance Eq Fixity where
(Fixity p1 dir1) == (Fixity p2 dir2) = p1==p2 && dir1 == dir2
data FixityDirection = InfixL | InfixR | InfixN
deriving (Eq, Data, Typeable)
instance Outputable FixityDirection where
ppr InfixL = ptext (sLit "infixl")
ppr InfixR = ptext (sLit "infixr")
ppr InfixN = ptext (sLit "infix")
maxPrecedence :: Int
maxPrecedence = 9
defaultFixity :: Fixity
defaultFixity = Fixity maxPrecedence InfixL
negateFixity, funTyFixity :: Fixity
negateFixity = Fixity 6 InfixL
funTyFixity = Fixity 0 InfixR
\end{code}
Consider
\begin{verbatim}
a `op1` b `op2` c
\end{verbatim}
@(compareFixity op1 op2)@ tells which way to arrange appication, or
whether there's an error.
\begin{code}
compareFixity :: Fixity -> Fixity
-> (Bool,
Bool)
compareFixity (Fixity prec1 dir1) (Fixity prec2 dir2)
= case prec1 `compare` prec2 of
GT -> left
LT -> right
EQ -> case (dir1, dir2) of
(InfixR, InfixR) -> right
(InfixL, InfixL) -> left
_ -> error_please
where
right = (False, True)
left = (False, False)
error_please = (True, False)
\end{code}
%************************************************************************
%* *
\subsection[Top-level/local]{Top-level/not-top level flag}
%* *
%************************************************************************
\begin{code}
data TopLevelFlag
= TopLevel
| NotTopLevel
isTopLevel, isNotTopLevel :: TopLevelFlag -> Bool
isNotTopLevel NotTopLevel = True
isNotTopLevel TopLevel = False
isTopLevel TopLevel = True
isTopLevel NotTopLevel = False
instance Outputable TopLevelFlag where
ppr TopLevel = ptext (sLit "<TopLevel>")
ppr NotTopLevel = ptext (sLit "<NotTopLevel>")
\end{code}
%************************************************************************
%* *
Top-level/not-top level flag
%* *
%************************************************************************
\begin{code}
data Boxity
= Boxed
| Unboxed
deriving( Eq, Data, Typeable )
isBoxed :: Boxity -> Bool
isBoxed Boxed = True
isBoxed Unboxed = False
\end{code}
%************************************************************************
%* *
Recursive/Non-Recursive flag
%* *
%************************************************************************
\begin{code}
data RecFlag = Recursive
| NonRecursive
deriving( Eq, Data, Typeable )
isRec :: RecFlag -> Bool
isRec Recursive = True
isRec NonRecursive = False
isNonRec :: RecFlag -> Bool
isNonRec Recursive = False
isNonRec NonRecursive = True
boolToRecFlag :: Bool -> RecFlag
boolToRecFlag True = Recursive
boolToRecFlag False = NonRecursive
instance Outputable RecFlag where
ppr Recursive = ptext (sLit "Recursive")
ppr NonRecursive = ptext (sLit "NonRecursive")
\end{code}
%************************************************************************
%* *
Instance overlap flag
%* *
%************************************************************************
\begin{code}
data OverlapFlag
= NoOverlap
| OverlapOk
| Incoherent
deriving( Eq )
instance Outputable OverlapFlag where
ppr NoOverlap = empty
ppr OverlapOk = ptext (sLit "[overlap ok]")
ppr Incoherent = ptext (sLit "[incoherent]")
\end{code}
%************************************************************************
%* *
Tuples
%* *
%************************************************************************
\begin{code}
data TupCon = TupCon Boxity Arity
instance Eq TupCon where
(TupCon b1 a1) == (TupCon b2 a2) = b1==b2 && a1==a2
tupleParens :: Boxity -> SDoc -> SDoc
tupleParens Boxed p = parens p
tupleParens Unboxed p = ptext (sLit "(#") <+> p <+> ptext (sLit "#)")
\end{code}
%************************************************************************
%* *
\subsection[Generic]{Generic flag}
%* *
%************************************************************************
This is the "Embedding-Projection pair" datatype, it contains
two pieces of code (normally either RenamedExpr's or Id's)
If we have a such a pair (EP from to), the idea is that 'from' and 'to'
represents functions of type
from :: T -> Tring
to :: Tring -> T
And we should have
to (from x) = x
T and Tring are arbitrary, but typically T is the 'main' type while
Tring is the 'representation' type. (This just helps us remember
whether to use 'from' or 'to'.
\begin{code}
data EP a = EP { fromEP :: a,
toEP :: a }
\end{code}
Embedding-projection pairs are used in several places:
First of all, each type constructor has an EP associated with it, the
code in EP converts (datatype T) from T to Tring and back again.
Secondly, when we are filling in Generic methods (in the typechecker,
tcMethodBinds), we are constructing bimaps by induction on the structure
of the type of the method signature.
%************************************************************************
%* *
\subsection{Occurrence information}
%* *
%************************************************************************
This data type is used exclusively by the simplifier, but it appears in a
SubstResult, which is currently defined in VarEnv, which is pretty near
the base of the module hierarchy. So it seemed simpler to put the
defn of OccInfo here, safely at the bottom
\begin{code}
data OccInfo
= NoOccInfo
| IAmDead
| OneOcc
!InsideLam
!OneBranch
!InterestingCxt
| IAmALoopBreaker
!RulesOnly
type RulesOnly = Bool
\end{code}
Note [LoopBreaker OccInfo]
~~~~~~~~~~~~~~~~~~~~~~~~~~
An OccInfo of (IAmLoopBreaker False) is used by the occurrence
analyser in two ways:
(a) to mark loop-breakers in a group of recursive
definitions (hence the name)
(b) to mark binders that must not be inlined in this phase
(perhaps it has a NOINLINE pragma)
Things with (IAmLoopBreaker False) do not get an unfolding
pinned on to them, so they are completely opaque.
See OccurAnal Note [Weak loop breakers] for (IAmLoopBreaker True).
\begin{code}
isNoOcc :: OccInfo -> Bool
isNoOcc NoOccInfo = True
isNoOcc _ = False
seqOccInfo :: OccInfo -> ()
seqOccInfo occ = occ `seq` ()
type InterestingCxt = Bool
type InsideLam = Bool
insideLam, notInsideLam :: InsideLam
insideLam = True
notInsideLam = False
type OneBranch = Bool
oneBranch, notOneBranch :: OneBranch
oneBranch = True
notOneBranch = False
isLoopBreaker :: OccInfo -> Bool
isLoopBreaker (IAmALoopBreaker _) = True
isLoopBreaker _ = False
isNonRuleLoopBreaker :: OccInfo -> Bool
isNonRuleLoopBreaker (IAmALoopBreaker False) = True
isNonRuleLoopBreaker _ = False
nonRuleLoopBreaker :: OccInfo
nonRuleLoopBreaker = IAmALoopBreaker False
isDeadOcc :: OccInfo -> Bool
isDeadOcc IAmDead = True
isDeadOcc _ = False
isOneOcc :: OccInfo -> Bool
isOneOcc (OneOcc {}) = True
isOneOcc _ = False
zapFragileOcc :: OccInfo -> OccInfo
zapFragileOcc (OneOcc {}) = NoOccInfo
zapFragileOcc occ = occ
\end{code}
\begin{code}
instance Outputable OccInfo where
ppr NoOccInfo = empty
ppr (IAmALoopBreaker ro) = ptext (sLit "LoopBreaker") <> if ro then char '!' else empty
ppr IAmDead = ptext (sLit "Dead")
ppr (OneOcc inside_lam one_branch int_cxt)
= ptext (sLit "Once") <> pp_lam <> pp_br <> pp_args
where
pp_lam | inside_lam = char 'L'
| otherwise = empty
pp_br | one_branch = empty
| otherwise = char '*'
pp_args | int_cxt = char '!'
| otherwise = empty
instance Show OccInfo where
showsPrec p occ = showsPrecSDoc p (ppr occ)
\end{code}
%************************************************************************
%* *
Strictness indication
%* *
%************************************************************************
The strictness annotations on types in data type declarations
e.g. data T = MkT !Int !(Bool,Bool)
\begin{code}
data HsBang = HsNoBang
| HsStrict
| HsUnpack
| HsUnpackFailed
deriving (Eq, Data, Typeable)
instance Outputable HsBang where
ppr HsNoBang = empty
ppr HsStrict = char '!'
ppr HsUnpack = ptext (sLit "{-# UNPACK #-} !")
ppr HsUnpackFailed = ptext (sLit "{-# UNPACK (failed) #-} !")
isBanged :: HsBang -> Bool
isBanged HsNoBang = False
isBanged _ = True
isMarkedUnboxed :: HsBang -> Bool
isMarkedUnboxed HsUnpack = True
isMarkedUnboxed _ = False
data StrictnessMark = MarkedStrict | NotMarkedStrict
instance Outputable StrictnessMark where
ppr MarkedStrict = ptext (sLit "!")
ppr NotMarkedStrict = empty
isMarkedStrict :: StrictnessMark -> Bool
isMarkedStrict NotMarkedStrict = False
isMarkedStrict _ = True
\end{code}
%************************************************************************
%* *
Default method specfication
%* *
%************************************************************************
The DefMethSpec enumeration just indicates what sort of default method
is used for a class. It is generated from source code, and present in
interface files; it is converted to Class.DefMeth before begin put in a
Class object.
\begin{code}
data DefMethSpec = NoDM
| VanillaDM
| GenericDM
instance Outputable DefMethSpec where
ppr NoDM = empty
ppr VanillaDM = ptext (sLit "{- Has default method -}")
ppr GenericDM = ptext (sLit "{- Has generic default method -}")
\end{code}
%************************************************************************
%* *
\subsection{Success flag}
%* *
%************************************************************************
\begin{code}
data SuccessFlag = Succeeded | Failed
instance Outputable SuccessFlag where
ppr Succeeded = ptext (sLit "Succeeded")
ppr Failed = ptext (sLit "Failed")
successIf :: Bool -> SuccessFlag
successIf True = Succeeded
successIf False = Failed
succeeded, failed :: SuccessFlag -> Bool
succeeded Succeeded = True
succeeded Failed = False
failed Succeeded = False
failed Failed = True
\end{code}
%************************************************************************
%* *
\subsection{Activation}
%* *
%************************************************************************
When a rule or inlining is active
\begin{code}
type PhaseNum = Int
data CompilerPhase
= Phase PhaseNum
| InitialPhase
instance Outputable CompilerPhase where
ppr (Phase n) = int n
ppr InitialPhase = ptext (sLit "InitialPhase")
data Activation = NeverActive
| AlwaysActive
| ActiveBefore PhaseNum
| ActiveAfter PhaseNum
deriving( Eq, Data, Typeable )
data RuleMatchInfo = ConLike
| FunLike
deriving( Eq, Data, Typeable, Show )
data InlinePragma
= InlinePragma
{ inl_inline :: InlineSpec
, inl_sat :: Maybe Arity
, inl_act :: Activation
, inl_rule :: RuleMatchInfo
} deriving( Eq, Data, Typeable )
data InlineSpec
= Inline
| Inlinable
| NoInline
| EmptyInlineSpec
deriving( Eq, Data, Typeable, Show )
\end{code}
Note [InlinePragma]
~~~~~~~~~~~~~~~~~~~
This data type mirrors what you can write in an INLINE or NOINLINE pragma in
the source program.
If you write nothing at all, you get defaultInlinePragma:
inl_inline = False
inl_act = AlwaysActive
inl_rule = FunLike
It's not possible to get that combination by *writing* something, so
if an Id has defaultInlinePragma it means the user didn't specify anything.
If inl_inline = True, then the Id should have an InlineRule unfolding.
Note [CONLIKE pragma]
~~~~~~~~~~~~~~~~~~~~~
The ConLike constructor of a RuleMatchInfo is aimed at the following.
Consider first
{-# RULE "r/cons" forall a as. r (a:as) = f (a+1) #-}
g b bs = let x = b:bs in ..x...x...(r x)...
Now, the rule applies to the (r x) term, because GHC "looks through"
the definition of 'x' to see that it is (b:bs).
Now consider
{-# RULE "r/f" forall v. r (f v) = f (v+1) #-}
g v = let x = f v in ..x...x...(r x)...
Normally the (r x) would *not* match the rule, because GHC would be
scared about duplicating the redex (f v), so it does not "look
through" the bindings.
However the CONLIKE modifier says to treat 'f' like a constructor in
this situation, and "look through" the unfolding for x. So (r x)
fires, yielding (f (v+1)).
This is all controlled with a user-visible pragma:
{-# NOINLINE CONLIKE [1] f #-}
The main effects of CONLIKE are:
- The occurrence analyser (OccAnal) and simplifier (Simplify) treat
CONLIKE thing like constructors, by ANF-ing them
- New function coreUtils.exprIsExpandable is like exprIsCheap, but
additionally spots applications of CONLIKE functions
- A CoreUnfolding has a field that caches exprIsExpandable
- The rule matcher consults this field. See
Note [Expanding variables] in Rules.lhs.
\begin{code}
isConLike :: RuleMatchInfo -> Bool
isConLike ConLike = True
isConLike _ = False
isFunLike :: RuleMatchInfo -> Bool
isFunLike FunLike = True
isFunLike _ = False
isEmptyInlineSpec :: InlineSpec -> Bool
isEmptyInlineSpec EmptyInlineSpec = True
isEmptyInlineSpec _ = False
defaultInlinePragma, alwaysInlinePragma, neverInlinePragma, dfunInlinePragma
:: InlinePragma
defaultInlinePragma = InlinePragma { inl_act = AlwaysActive
, inl_rule = FunLike
, inl_inline = EmptyInlineSpec
, inl_sat = Nothing }
alwaysInlinePragma = defaultInlinePragma { inl_inline = Inline }
neverInlinePragma = defaultInlinePragma { inl_act = NeverActive }
inlinePragmaSpec :: InlinePragma -> InlineSpec
inlinePragmaSpec = inl_inline
dfunInlinePragma = defaultInlinePragma { inl_act = AlwaysActive
, inl_rule = ConLike }
isDefaultInlinePragma :: InlinePragma -> Bool
isDefaultInlinePragma (InlinePragma { inl_act = activation
, inl_rule = match_info
, inl_inline = inline })
= isEmptyInlineSpec inline && isAlwaysActive activation && isFunLike match_info
isInlinePragma :: InlinePragma -> Bool
isInlinePragma prag = case inl_inline prag of
Inline -> True
_ -> False
isInlinablePragma :: InlinePragma -> Bool
isInlinablePragma prag = case inl_inline prag of
Inlinable -> True
_ -> False
isAnyInlinePragma :: InlinePragma -> Bool
isAnyInlinePragma prag = case inl_inline prag of
Inline -> True
Inlinable -> True
_ -> False
inlinePragmaSat :: InlinePragma -> Maybe Arity
inlinePragmaSat = inl_sat
inlinePragmaActivation :: InlinePragma -> Activation
inlinePragmaActivation (InlinePragma { inl_act = activation }) = activation
inlinePragmaRuleMatchInfo :: InlinePragma -> RuleMatchInfo
inlinePragmaRuleMatchInfo (InlinePragma { inl_rule = info }) = info
setInlinePragmaActivation :: InlinePragma -> Activation -> InlinePragma
setInlinePragmaActivation prag activation = prag { inl_act = activation }
setInlinePragmaRuleMatchInfo :: InlinePragma -> RuleMatchInfo -> InlinePragma
setInlinePragmaRuleMatchInfo prag info = prag { inl_rule = info }
instance Outputable Activation where
ppr AlwaysActive = brackets (ptext (sLit "ALWAYS"))
ppr NeverActive = brackets (ptext (sLit "NEVER"))
ppr (ActiveBefore n) = brackets (char '~' <> int n)
ppr (ActiveAfter n) = brackets (int n)
instance Outputable RuleMatchInfo where
ppr ConLike = ptext (sLit "CONLIKE")
ppr FunLike = ptext (sLit "FUNLIKE")
instance Outputable InlineSpec where
ppr Inline = ptext (sLit "INLINE")
ppr NoInline = ptext (sLit "NOINLINE")
ppr Inlinable = ptext (sLit "INLINABLE")
ppr EmptyInlineSpec = empty
instance Outputable InlinePragma where
ppr (InlinePragma { inl_inline = inline, inl_act = activation
, inl_rule = info, inl_sat = mb_arity })
= ppr inline <> pp_act inline activation <+> pp_sat <+> pp_info
where
pp_act Inline AlwaysActive = empty
pp_act NoInline NeverActive = empty
pp_act _ act = ppr act
pp_sat | Just ar <- mb_arity = parens (ptext (sLit "sat-args=") <> int ar)
| otherwise = empty
pp_info | isFunLike info = empty
| otherwise = ppr info
isActive :: CompilerPhase -> Activation -> Bool
isActive InitialPhase AlwaysActive = True
isActive InitialPhase (ActiveBefore {}) = True
isActive InitialPhase _ = False
isActive (Phase p) act = isActiveIn p act
isActiveIn :: PhaseNum -> Activation -> Bool
isActiveIn _ NeverActive = False
isActiveIn _ AlwaysActive = True
isActiveIn p (ActiveAfter n) = p <= n
isActiveIn p (ActiveBefore n) = p > n
isNeverActive, isAlwaysActive, isEarlyActive :: Activation -> Bool
isNeverActive NeverActive = True
isNeverActive _ = False
isAlwaysActive AlwaysActive = True
isAlwaysActive _ = False
isEarlyActive AlwaysActive = True
isEarlyActive (ActiveBefore {}) = True
isEarlyActive _ = False
\end{code}