{- (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} -} {-# LANGUAGE DeriveDataTypeable #-} module BasicTypes( Version, bumpVersion, initialVersion, LeftOrRight(..), pickLR, ConTag, ConTagZ, fIRST_TAG, Arity, RepArity, JoinArity, Alignment, mkAlignment, alignmentOf, alignmentBytes, PromotionFlag(..), isPromoted, FunctionOrData(..), WarningTxt(..), pprWarningTxtForMsg, StringLiteral(..), Fixity(..), FixityDirection(..), defaultFixity, maxPrecedence, minPrecedence, negateFixity, funTyFixity, compareFixity, LexicalFixity(..), RecFlag(..), isRec, isNonRec, boolToRecFlag, Origin(..), isGenerated, RuleName, pprRuleName, TopLevelFlag(..), isTopLevel, isNotTopLevel, OverlapFlag(..), OverlapMode(..), setOverlapModeMaybe, hasOverlappingFlag, hasOverlappableFlag, hasIncoherentFlag, Boxity(..), isBoxed, PprPrec(..), topPrec, sigPrec, opPrec, funPrec, appPrec, maybeParen, TupleSort(..), tupleSortBoxity, boxityTupleSort, tupleParens, sumParens, pprAlternative, -- ** The OneShotInfo type OneShotInfo(..), noOneShotInfo, hasNoOneShotInfo, isOneShotInfo, bestOneShot, worstOneShot, OccInfo(..), noOccInfo, seqOccInfo, zapFragileOcc, isOneOcc, isDeadOcc, isStrongLoopBreaker, isWeakLoopBreaker, isManyOccs, strongLoopBreaker, weakLoopBreaker, InsideLam, insideLam, notInsideLam, OneBranch, oneBranch, notOneBranch, InterestingCxt, TailCallInfo(..), tailCallInfo, zapOccTailCallInfo, isAlwaysTailCalled, EP(..), DefMethSpec(..), SwapFlag(..), flipSwap, unSwap, isSwapped, CompilerPhase(..), PhaseNum, Activation(..), isActive, isActiveIn, competesWith, isNeverActive, isAlwaysActive, isEarlyActive, activeAfterInitial, activeDuringFinal, RuleMatchInfo(..), isConLike, isFunLike, InlineSpec(..), noUserInlineSpec, InlinePragma(..), defaultInlinePragma, alwaysInlinePragma, neverInlinePragma, dfunInlinePragma, isDefaultInlinePragma, isInlinePragma, isInlinablePragma, isAnyInlinePragma, inlinePragmaSpec, inlinePragmaSat, inlinePragmaActivation, inlinePragmaRuleMatchInfo, setInlinePragmaActivation, setInlinePragmaRuleMatchInfo, pprInline, pprInlineDebug, SuccessFlag(..), succeeded, failed, successIf, IntegralLit(..), FractionalLit(..), negateIntegralLit, negateFractionalLit, mkIntegralLit, mkFractionalLit, integralFractionalLit, SourceText(..), pprWithSourceText, IntWithInf, infinity, treatZeroAsInf, mkIntWithInf, intGtLimit, SpliceExplicitFlag(..), TypeOrKind(..), isTypeLevel, isKindLevel ) where import GhcPrelude import FastString import Outputable import SrcLoc ( Located,unLoc ) import Data.Data hiding (Fixity, Prefix, Infix) import Data.Function (on) import Data.Bits {- ************************************************************************ * * Binary choice * * ************************************************************************ -} data LeftOrRight = CLeft | CRight deriving( Eq, Data ) pickLR :: LeftOrRight -> (a,a) -> a pickLR CLeft (l,_) = l pickLR CRight (_,r) = r instance Outputable LeftOrRight where ppr CLeft = text "Left" ppr CRight = text "Right" {- ************************************************************************ * * \subsection[Arity]{Arity} * * ************************************************************************ -} -- | The number of value arguments that can be applied to a value before it does -- "real work". So: -- fib 100 has arity 0 -- \x -> fib x has arity 1 -- See also Note [Definition of arity] in CoreArity type Arity = Int -- | Representation Arity -- -- The number of represented arguments that can be applied to a value before it does -- "real work". So: -- fib 100 has representation arity 0 -- \x -> fib x has representation arity 1 -- \(# x, y #) -> fib (x + y) has representation arity 2 type RepArity = Int -- | The number of arguments that a join point takes. Unlike the arity of a -- function, this is a purely syntactic property and is fixed when the join -- point is created (or converted from a value). Both type and value arguments -- are counted. type JoinArity = Int {- ************************************************************************ * * Constructor tags * * ************************************************************************ -} -- | Constructor Tag -- -- Type of the tags associated with each constructor possibility or superclass -- selector type ConTag = Int -- | A *zero-indexed* constructor tag type ConTagZ = Int fIRST_TAG :: ConTag -- ^ Tags are allocated from here for real constructors -- or for superclass selectors fIRST_TAG = 1 {- ************************************************************************ * * \subsection[Alignment]{Alignment} * * ************************************************************************ -} -- | A power-of-two alignment newtype Alignment = Alignment { alignmentBytes :: Int } deriving (Eq, Ord) -- Builds an alignment, throws on non power of 2 input. This is not -- ideal, but convenient for internal use and better then silently -- passing incorrect data. mkAlignment :: Int -> Alignment mkAlignment n | n == 1 = Alignment 1 | n == 2 = Alignment 2 | n == 4 = Alignment 4 | n == 8 = Alignment 8 | n == 16 = Alignment 16 | n == 32 = Alignment 32 | n == 64 = Alignment 64 | n == 128 = Alignment 128 | n == 256 = Alignment 256 | n == 512 = Alignment 512 | otherwise = panic "mkAlignment: received either a non power of 2 argument or > 512" -- Calculates an alignment of a number. x is aligned at N bytes means -- the remainder from x / N is zero. Currently, interested in N <= 8, -- but can be expanded to N <= 16 or N <= 32 if used within SSE or AVX -- context. alignmentOf :: Int -> Alignment alignmentOf x = case x .&. 7 of 0 -> Alignment 8 4 -> Alignment 4 2 -> Alignment 2 _ -> Alignment 1 instance Outputable Alignment where ppr (Alignment m) = ppr m {- ************************************************************************ * * One-shot information * * ************************************************************************ -} -- | If the 'Id' is a lambda-bound variable then it may have lambda-bound -- variable info. Sometimes we know whether the lambda binding this variable -- is a \"one-shot\" lambda; that is, whether it is applied at most once. -- -- This information may be useful in optimisation, as computations may -- safely be floated inside such a lambda without risk of duplicating -- work. data OneShotInfo = NoOneShotInfo -- ^ No information | OneShotLam -- ^ The lambda is applied at most once. deriving (Eq) -- | It is always safe to assume that an 'Id' has no lambda-bound variable information noOneShotInfo :: OneShotInfo noOneShotInfo = NoOneShotInfo isOneShotInfo, hasNoOneShotInfo :: OneShotInfo -> Bool isOneShotInfo OneShotLam = True isOneShotInfo _ = False hasNoOneShotInfo NoOneShotInfo = True hasNoOneShotInfo _ = False worstOneShot, bestOneShot :: OneShotInfo -> OneShotInfo -> OneShotInfo worstOneShot NoOneShotInfo _ = NoOneShotInfo worstOneShot OneShotLam os = os bestOneShot NoOneShotInfo os = os bestOneShot OneShotLam _ = OneShotLam pprOneShotInfo :: OneShotInfo -> SDoc pprOneShotInfo NoOneShotInfo = empty pprOneShotInfo OneShotLam = text "OneShot" instance Outputable OneShotInfo where ppr = pprOneShotInfo {- ************************************************************************ * * Swap flag * * ************************************************************************ -} data SwapFlag = NotSwapped -- Args are: actual, expected | IsSwapped -- Args are: expected, actual instance Outputable SwapFlag where ppr IsSwapped = text "Is-swapped" ppr NotSwapped = text "Not-swapped" flipSwap :: SwapFlag -> SwapFlag flipSwap IsSwapped = NotSwapped flipSwap NotSwapped = IsSwapped isSwapped :: SwapFlag -> Bool isSwapped IsSwapped = True isSwapped NotSwapped = False unSwap :: SwapFlag -> (a->a->b) -> a -> a -> b unSwap NotSwapped f a b = f a b unSwap IsSwapped f a b = f b a {- ********************************************************************* * * Promotion flag * * ********************************************************************* -} -- | Is a TyCon a promoted data constructor or just a normal type constructor? data PromotionFlag = NotPromoted | IsPromoted deriving ( Eq, Data ) isPromoted :: PromotionFlag -> Bool isPromoted IsPromoted = True isPromoted NotPromoted = False {- ************************************************************************ * * \subsection[FunctionOrData]{FunctionOrData} * * ************************************************************************ -} data FunctionOrData = IsFunction | IsData deriving (Eq, Ord, Data) instance Outputable FunctionOrData where ppr IsFunction = text "(function)" ppr IsData = text "(data)" {- ************************************************************************ * * \subsection[Version]{Module and identifier version numbers} * * ************************************************************************ -} type Version = Int bumpVersion :: Version -> Version bumpVersion v = v+1 initialVersion :: Version initialVersion = 1 {- ************************************************************************ * * Deprecations * * ************************************************************************ -} -- | A String Literal in the source, including its original raw format for use by -- source to source manipulation tools. data StringLiteral = StringLiteral { sl_st :: SourceText, -- literal raw source. -- See not [Literal source text] sl_fs :: FastString -- literal string value } deriving Data instance Eq StringLiteral where (StringLiteral _ a) == (StringLiteral _ b) = a == b instance Outputable StringLiteral where ppr sl = pprWithSourceText (sl_st sl) (ftext $ sl_fs sl) -- | Warning Text -- -- reason/explanation from a WARNING or DEPRECATED pragma data WarningTxt = WarningTxt (Located SourceText) [Located StringLiteral] | DeprecatedTxt (Located SourceText) [Located StringLiteral] deriving (Eq, Data) instance Outputable WarningTxt where ppr (WarningTxt lsrc ws) = case unLoc lsrc of NoSourceText -> pp_ws ws SourceText src -> text src <+> pp_ws ws <+> text "#-}" ppr (DeprecatedTxt lsrc ds) = case unLoc lsrc of NoSourceText -> pp_ws ds SourceText src -> text src <+> pp_ws ds <+> text "#-}" pp_ws :: [Located StringLiteral] -> SDoc pp_ws [l] = ppr $ unLoc l pp_ws ws = text "[" <+> vcat (punctuate comma (map (ppr . unLoc) ws)) <+> text "]" pprWarningTxtForMsg :: WarningTxt -> SDoc pprWarningTxtForMsg (WarningTxt _ ws) = doubleQuotes (vcat (map (ftext . sl_fs . unLoc) ws)) pprWarningTxtForMsg (DeprecatedTxt _ ds) = text "Deprecated:" <+> doubleQuotes (vcat (map (ftext . sl_fs . unLoc) ds)) {- ************************************************************************ * * Rules * * ************************************************************************ -} type RuleName = FastString pprRuleName :: RuleName -> SDoc pprRuleName rn = doubleQuotes (ftext rn) {- ************************************************************************ * * \subsection[Fixity]{Fixity info} * * ************************************************************************ -} ------------------------ data Fixity = Fixity SourceText Int FixityDirection -- Note [Pragma source text] deriving Data instance Outputable Fixity where ppr (Fixity _ prec dir) = hcat [ppr dir, space, int prec] instance Eq Fixity where -- Used to determine if two fixities conflict (Fixity _ p1 dir1) == (Fixity _ p2 dir2) = p1==p2 && dir1 == dir2 ------------------------ data FixityDirection = InfixL | InfixR | InfixN deriving (Eq, Data) instance Outputable FixityDirection where ppr InfixL = text "infixl" ppr InfixR = text "infixr" ppr InfixN = text "infix" ------------------------ maxPrecedence, minPrecedence :: Int maxPrecedence = 9 minPrecedence = 0 defaultFixity :: Fixity defaultFixity = Fixity NoSourceText maxPrecedence InfixL negateFixity, funTyFixity :: Fixity -- Wired-in fixities negateFixity = Fixity NoSourceText 6 InfixL -- Fixity of unary negate funTyFixity = Fixity NoSourceText (-1) InfixR -- Fixity of '->', see #15235 {- Consider \begin{verbatim} a `op1` b `op2` c \end{verbatim} @(compareFixity op1 op2)@ tells which way to arrange application, or whether there's an error. -} compareFixity :: Fixity -> Fixity -> (Bool, -- Error please Bool) -- Associate to the right: a op1 (b op2 c) 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) -- |Captures the fixity of declarations as they are parsed. This is not -- necessarily the same as the fixity declaration, as the normal fixity may be -- overridden using parens or backticks. data LexicalFixity = Prefix | Infix deriving (Data,Eq) instance Outputable LexicalFixity where ppr Prefix = text "Prefix" ppr Infix = text "Infix" {- ************************************************************************ * * \subsection[Top-level/local]{Top-level/not-top level flag} * * ************************************************************************ -} 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 = text "<TopLevel>" ppr NotTopLevel = text "<NotTopLevel>" {- ************************************************************************ * * Boxity flag * * ************************************************************************ -} data Boxity = Boxed | Unboxed deriving( Eq, Data ) isBoxed :: Boxity -> Bool isBoxed Boxed = True isBoxed Unboxed = False instance Outputable Boxity where ppr Boxed = text "Boxed" ppr Unboxed = text "Unboxed" {- ************************************************************************ * * Recursive/Non-Recursive flag * * ************************************************************************ -} -- | Recursivity Flag data RecFlag = Recursive | NonRecursive deriving( Eq, Data ) 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 = text "Recursive" ppr NonRecursive = text "NonRecursive" {- ************************************************************************ * * Code origin * * ************************************************************************ -} data Origin = FromSource | Generated deriving( Eq, Data ) isGenerated :: Origin -> Bool isGenerated Generated = True isGenerated FromSource = False instance Outputable Origin where ppr FromSource = text "FromSource" ppr Generated = text "Generated" {- ************************************************************************ * * Instance overlap flag * * ************************************************************************ -} -- | The semantics allowed for overlapping instances for a particular -- instance. See Note [Safe Haskell isSafeOverlap] (in `InstEnv.hs`) for a -- explanation of the `isSafeOverlap` field. -- -- - 'ApiAnnotation.AnnKeywordId' : -- 'ApiAnnotation.AnnOpen' @'\{-\# OVERLAPPABLE'@ or -- @'\{-\# OVERLAPPING'@ or -- @'\{-\# OVERLAPS'@ or -- @'\{-\# INCOHERENT'@, -- 'ApiAnnotation.AnnClose' @`\#-\}`@, -- For details on above see note [Api annotations] in ApiAnnotation data OverlapFlag = OverlapFlag { overlapMode :: OverlapMode , isSafeOverlap :: Bool } deriving (Eq, Data) setOverlapModeMaybe :: OverlapFlag -> Maybe OverlapMode -> OverlapFlag setOverlapModeMaybe f Nothing = f setOverlapModeMaybe f (Just m) = f { overlapMode = m } hasIncoherentFlag :: OverlapMode -> Bool hasIncoherentFlag mode = case mode of Incoherent _ -> True _ -> False hasOverlappableFlag :: OverlapMode -> Bool hasOverlappableFlag mode = case mode of Overlappable _ -> True Overlaps _ -> True Incoherent _ -> True _ -> False hasOverlappingFlag :: OverlapMode -> Bool hasOverlappingFlag mode = case mode of Overlapping _ -> True Overlaps _ -> True Incoherent _ -> True _ -> False data OverlapMode -- See Note [Rules for instance lookup] in InstEnv = NoOverlap SourceText -- See Note [Pragma source text] -- ^ This instance must not overlap another `NoOverlap` instance. -- However, it may be overlapped by `Overlapping` instances, -- and it may overlap `Overlappable` instances. | Overlappable SourceText -- See Note [Pragma source text] -- ^ Silently ignore this instance if you find a -- more specific one that matches the constraint -- you are trying to resolve -- -- Example: constraint (Foo [Int]) -- instance Foo [Int] -- instance {-# OVERLAPPABLE #-} Foo [a] -- -- Since the second instance has the Overlappable flag, -- the first instance will be chosen (otherwise -- its ambiguous which to choose) | Overlapping SourceText -- See Note [Pragma source text] -- ^ Silently ignore any more general instances that may be -- used to solve the constraint. -- -- Example: constraint (Foo [Int]) -- instance {-# OVERLAPPING #-} Foo [Int] -- instance Foo [a] -- -- Since the first instance has the Overlapping flag, -- the second---more general---instance will be ignored (otherwise -- it is ambiguous which to choose) | Overlaps SourceText -- See Note [Pragma source text] -- ^ Equivalent to having both `Overlapping` and `Overlappable` flags. | Incoherent SourceText -- See Note [Pragma source text] -- ^ Behave like Overlappable and Overlapping, and in addition pick -- an an arbitrary one if there are multiple matching candidates, and -- don't worry about later instantiation -- -- Example: constraint (Foo [b]) -- instance {-# INCOHERENT -} Foo [Int] -- instance Foo [a] -- Without the Incoherent flag, we'd complain that -- instantiating 'b' would change which instance -- was chosen. See also note [Incoherent instances] in InstEnv deriving (Eq, Data) instance Outputable OverlapFlag where ppr flag = ppr (overlapMode flag) <+> pprSafeOverlap (isSafeOverlap flag) instance Outputable OverlapMode where ppr (NoOverlap _) = empty ppr (Overlappable _) = text "[overlappable]" ppr (Overlapping _) = text "[overlapping]" ppr (Overlaps _) = text "[overlap ok]" ppr (Incoherent _) = text "[incoherent]" pprSafeOverlap :: Bool -> SDoc pprSafeOverlap True = text "[safe]" pprSafeOverlap False = empty {- ************************************************************************ * * Precedence * * ************************************************************************ -} -- | A general-purpose pretty-printing precedence type. newtype PprPrec = PprPrec Int deriving (Eq, Ord, Show) -- See Note [Precedence in types] topPrec, sigPrec, funPrec, opPrec, appPrec :: PprPrec topPrec = PprPrec 0 -- No parens sigPrec = PprPrec 1 -- Explicit type signatures funPrec = PprPrec 2 -- Function args; no parens for constructor apps -- See [Type operator precedence] for why both -- funPrec and opPrec exist. opPrec = PprPrec 2 -- Infix operator appPrec = PprPrec 3 -- Constructor args; no parens for atomic maybeParen :: PprPrec -> PprPrec -> SDoc -> SDoc maybeParen ctxt_prec inner_prec pretty | ctxt_prec < inner_prec = pretty | otherwise = parens pretty {- Note [Precedence in types] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Many pretty-printing functions have type ppr_ty :: PprPrec -> Type -> SDoc The PprPrec gives the binding strength of the context. For example, in T ty1 ty2 we will pretty-print 'ty1' and 'ty2' with the call (ppr_ty appPrec ty) to indicate that the context is that of an argument of a TyConApp. We use this consistently for Type and HsType. Note [Type operator precedence] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We don't keep the fixity of type operators in the operator. So the pretty printer follows the following precedence order: TyConPrec Type constructor application TyOpPrec/FunPrec Operator application and function arrow We have funPrec and opPrec to represent the precedence of function arrow and type operators respectively, but currently we implement funPrec == opPrec, so that we don't distinguish the two. Reason: it's hard to parse a type like a ~ b => c * d -> e - f By treating opPrec = funPrec we end up with more parens (a ~ b) => (c * d) -> (e - f) But the two are different constructors of PprPrec so we could make (->) bind more or less tightly if we wanted. -} {- ************************************************************************ * * Tuples * * ************************************************************************ -} data TupleSort = BoxedTuple | UnboxedTuple | ConstraintTuple deriving( Eq, Data ) instance Outputable TupleSort where ppr ts = text $ case ts of BoxedTuple -> "BoxedTuple" UnboxedTuple -> "UnboxedTuple" ConstraintTuple -> "ConstraintTuple" tupleSortBoxity :: TupleSort -> Boxity tupleSortBoxity BoxedTuple = Boxed tupleSortBoxity UnboxedTuple = Unboxed tupleSortBoxity ConstraintTuple = Boxed boxityTupleSort :: Boxity -> TupleSort boxityTupleSort Boxed = BoxedTuple boxityTupleSort Unboxed = UnboxedTuple tupleParens :: TupleSort -> SDoc -> SDoc tupleParens BoxedTuple p = parens p tupleParens UnboxedTuple p = text "(#" <+> p <+> ptext (sLit "#)") tupleParens ConstraintTuple p -- In debug-style write (% Eq a, Ord b %) = ifPprDebug (text "(%" <+> p <+> ptext (sLit "%)")) (parens p) {- ************************************************************************ * * Sums * * ************************************************************************ -} sumParens :: SDoc -> SDoc sumParens p = ptext (sLit "(#") <+> p <+> ptext (sLit "#)") -- | Pretty print an alternative in an unboxed sum e.g. "| a | |". pprAlternative :: (a -> SDoc) -- ^ The pretty printing function to use -> a -- ^ The things to be pretty printed -> ConTag -- ^ Alternative (one-based) -> Arity -- ^ Arity -> SDoc -- ^ 'SDoc' where the alternative havs been pretty -- printed and finally packed into a paragraph. pprAlternative pp x alt arity = fsep (replicate (alt - 1) vbar ++ [pp x] ++ replicate (arity - alt) vbar) {- ************************************************************************ * * \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'. -} -- | Embedding Projection pair data EP a = EP { fromEP :: a, -- :: T -> Tring toEP :: a } -- :: Tring -> T {- 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 -} -- | identifier Occurrence Information data OccInfo = ManyOccs { occ_tail :: !TailCallInfo } -- ^ There are many occurrences, or unknown occurrences | IAmDead -- ^ Marks unused variables. Sometimes useful for -- lambda and case-bound variables. | OneOcc { occ_in_lam :: !InsideLam , occ_one_br :: !OneBranch , occ_int_cxt :: !InterestingCxt , occ_tail :: !TailCallInfo } -- ^ Occurs exactly once (per branch), not inside a rule -- | This identifier breaks a loop of mutually recursive functions. The field -- marks whether it is only a loop breaker due to a reference in a rule | IAmALoopBreaker { occ_rules_only :: !RulesOnly , occ_tail :: !TailCallInfo } -- Note [LoopBreaker OccInfo] deriving (Eq) type RulesOnly = Bool {- Note [LoopBreaker OccInfo] ~~~~~~~~~~~~~~~~~~~~~~~~~~ IAmALoopBreaker True <=> A "weak" or rules-only loop breaker Do not preInlineUnconditionally IAmALoopBreaker False <=> A "strong" loop breaker Do not inline at all See OccurAnal Note [Weak loop breakers] -} noOccInfo :: OccInfo noOccInfo = ManyOccs { occ_tail = NoTailCallInfo } isManyOccs :: OccInfo -> Bool isManyOccs ManyOccs{} = True isManyOccs _ = False seqOccInfo :: OccInfo -> () seqOccInfo occ = occ `seq` () ----------------- -- | Interesting Context type InterestingCxt = Bool -- True <=> Function: is applied -- Data value: scrutinised by a case with -- at least one non-DEFAULT branch ----------------- -- | Inside Lambda type InsideLam = Bool -- True <=> Occurs inside a non-linear lambda -- Substituting a redex for this occurrence is -- dangerous because it might duplicate work. insideLam, notInsideLam :: InsideLam insideLam = True notInsideLam = False ----------------- type OneBranch = Bool -- True <=> Occurs in only one case branch -- so no code-duplication issue to worry about oneBranch, notOneBranch :: OneBranch oneBranch = True notOneBranch = False ----------------- data TailCallInfo = AlwaysTailCalled JoinArity -- See Note [TailCallInfo] | NoTailCallInfo deriving (Eq) tailCallInfo :: OccInfo -> TailCallInfo tailCallInfo IAmDead = NoTailCallInfo tailCallInfo other = occ_tail other zapOccTailCallInfo :: OccInfo -> OccInfo zapOccTailCallInfo IAmDead = IAmDead zapOccTailCallInfo occ = occ { occ_tail = NoTailCallInfo } isAlwaysTailCalled :: OccInfo -> Bool isAlwaysTailCalled occ = case tailCallInfo occ of AlwaysTailCalled{} -> True NoTailCallInfo -> False instance Outputable TailCallInfo where ppr (AlwaysTailCalled ar) = sep [ text "Tail", int ar ] ppr _ = empty ----------------- strongLoopBreaker, weakLoopBreaker :: OccInfo strongLoopBreaker = IAmALoopBreaker False NoTailCallInfo weakLoopBreaker = IAmALoopBreaker True NoTailCallInfo isWeakLoopBreaker :: OccInfo -> Bool isWeakLoopBreaker (IAmALoopBreaker{}) = True isWeakLoopBreaker _ = False isStrongLoopBreaker :: OccInfo -> Bool isStrongLoopBreaker (IAmALoopBreaker { occ_rules_only = False }) = True -- Loop-breaker that breaks a non-rule cycle isStrongLoopBreaker _ = False isDeadOcc :: OccInfo -> Bool isDeadOcc IAmDead = True isDeadOcc _ = False isOneOcc :: OccInfo -> Bool isOneOcc (OneOcc {}) = True isOneOcc _ = False zapFragileOcc :: OccInfo -> OccInfo -- Keep only the most robust data: deadness, loop-breaker-hood zapFragileOcc (OneOcc {}) = noOccInfo zapFragileOcc occ = zapOccTailCallInfo occ instance Outputable OccInfo where -- only used for debugging; never parsed. KSW 1999-07 ppr (ManyOccs tails) = pprShortTailCallInfo tails ppr IAmDead = text "Dead" ppr (IAmALoopBreaker rule_only tails) = text "LoopBreaker" <> pp_ro <> pprShortTailCallInfo tails where pp_ro | rule_only = char '!' | otherwise = empty ppr (OneOcc inside_lam one_branch int_cxt tail_info) = text "Once" <> pp_lam <> pp_br <> pp_args <> pp_tail where pp_lam | inside_lam = char 'L' | otherwise = empty pp_br | one_branch = empty | otherwise = char '*' pp_args | int_cxt = char '!' | otherwise = empty pp_tail = pprShortTailCallInfo tail_info pprShortTailCallInfo :: TailCallInfo -> SDoc pprShortTailCallInfo (AlwaysTailCalled ar) = char 'T' <> brackets (int ar) pprShortTailCallInfo NoTailCallInfo = empty {- Note [TailCallInfo] ~~~~~~~~~~~~~~~~~~~ The occurrence analyser determines what can be made into a join point, but it doesn't change the binder into a JoinId because then it would be inconsistent with the occurrences. Thus it's left to the simplifier (or to simpleOptExpr) to change the IdDetails. The AlwaysTailCalled marker actually means slightly more than simply that the function is always tail-called. See Note [Invariants on join points]. This info is quite fragile and should not be relied upon unless the occurrence analyser has *just* run. Use 'Id.isJoinId_maybe' for the permanent state of the join-point-hood of a binder; a join id itself will not be marked AlwaysTailCalled. Note that there is a 'TailCallInfo' on a 'ManyOccs' value. One might expect that being tail-called would mean that the variable could only appear once per branch (thus getting a `OneOcc { occ_one_br = True }` occurrence info), but a join point can also be invoked from other join points, not just from case branches: let j1 x = ... j2 y = ... j1 z {- tail call -} ... in case w of A -> j1 v B -> j2 u C -> j2 q Here both 'j1' and 'j2' will get marked AlwaysTailCalled, but j1 will get ManyOccs and j2 will get `OneOcc { occ_one_br = True }`. ************************************************************************ * * Default method specification * * ************************************************************************ 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.DefMethInfo before begin put in a Class object. -} -- | Default Method Specification data DefMethSpec ty = VanillaDM -- Default method given with polymorphic code | GenericDM ty -- Default method given with code of this type instance Outputable (DefMethSpec ty) where ppr VanillaDM = text "{- Has default method -}" ppr (GenericDM {}) = text "{- Has generic default method -}" {- ************************************************************************ * * \subsection{Success flag} * * ************************************************************************ -} data SuccessFlag = Succeeded | Failed instance Outputable SuccessFlag where ppr Succeeded = text "Succeeded" ppr Failed = text "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 {- ************************************************************************ * * \subsection{Source Text} * * ************************************************************************ Keeping Source Text for source to source conversions Note [Pragma source text] ~~~~~~~~~~~~~~~~~~~~~~~~~ The lexer does a case-insensitive match for pragmas, as well as accepting both UK and US spelling variants. So {-# SPECIALISE #-} {-# SPECIALIZE #-} {-# Specialize #-} will all generate ITspec_prag token for the start of the pragma. In order to be able to do source to source conversions, the original source text for the token needs to be preserved, hence the `SourceText` field. So the lexer will then generate ITspec_prag "{ -# SPECIALISE" ITspec_prag "{ -# SPECIALIZE" ITspec_prag "{ -# Specialize" for the cases above. [without the space between '{' and '-', otherwise this comment won't parse] Note [Literal source text] ~~~~~~~~~~~~~~~~~~~~~~~~~~ The lexer/parser converts literals from their original source text versions to an appropriate internal representation. This is a problem for tools doing source to source conversions, so the original source text is stored in literals where this can occur. Motivating examples for HsLit HsChar '\n' == '\x20` HsCharPrim '\x41`# == `A` HsString "\x20\x41" == " A" HsStringPrim "\x20"# == " "# HsInt 001 == 1 HsIntPrim 002# == 2# HsWordPrim 003## == 3## HsInt64Prim 004## == 4## HsWord64Prim 005## == 5## HsInteger 006 == 6 For OverLitVal HsIntegral 003 == 0x003 HsIsString "\x41nd" == "And" -} -- Note [Literal source text],[Pragma source text] data SourceText = SourceText String | NoSourceText -- ^ For when code is generated, e.g. TH, -- deriving. The pretty printer will then make -- its own representation of the item. deriving (Data, Show, Eq ) instance Outputable SourceText where ppr (SourceText s) = text "SourceText" <+> text s ppr NoSourceText = text "NoSourceText" -- | Special combinator for showing string literals. pprWithSourceText :: SourceText -> SDoc -> SDoc pprWithSourceText NoSourceText d = d pprWithSourceText (SourceText src) _ = text src {- ************************************************************************ * * \subsection{Activation} * * ************************************************************************ When a rule or inlining is active -} -- | Phase Number type PhaseNum = Int -- Compilation phase -- Phases decrease towards zero -- Zero is the last phase data CompilerPhase = Phase PhaseNum | InitialPhase -- The first phase -- number = infinity! instance Outputable CompilerPhase where ppr (Phase n) = int n ppr InitialPhase = text "InitialPhase" activeAfterInitial :: Activation -- Active in the first phase after the initial phase -- Currently we have just phases [2,1,0] activeAfterInitial = ActiveAfter NoSourceText 2 activeDuringFinal :: Activation -- Active in the final simplification phase (which is repeated) activeDuringFinal = ActiveAfter NoSourceText 0 -- See note [Pragma source text] data Activation = NeverActive | AlwaysActive | ActiveBefore SourceText PhaseNum -- Active only *strictly before* this phase | ActiveAfter SourceText PhaseNum -- Active in this phase and later deriving( Eq, Data ) -- Eq used in comparing rules in GHC.Hs.Decls -- | Rule Match Information data RuleMatchInfo = ConLike -- See Note [CONLIKE pragma] | FunLike deriving( Eq, Data, Show ) -- Show needed for Lexer.x data InlinePragma -- Note [InlinePragma] = InlinePragma { inl_src :: SourceText -- Note [Pragma source text] , inl_inline :: InlineSpec -- See Note [inl_inline and inl_act] , inl_sat :: Maybe Arity -- Just n <=> Inline only when applied to n -- explicit (non-type, non-dictionary) args -- That is, inl_sat describes the number of *source-code* -- arguments the thing must be applied to. We add on the -- number of implicit, dictionary arguments when making -- the Unfolding, and don't look at inl_sat further , inl_act :: Activation -- Says during which phases inlining is allowed -- See Note [inl_inline and inl_act] , inl_rule :: RuleMatchInfo -- Should the function be treated like a constructor? } deriving( Eq, Data ) -- | Inline Specification data InlineSpec -- What the user's INLINE pragma looked like = Inline -- User wrote INLINE | Inlinable -- User wrote INLINABLE | NoInline -- User wrote NOINLINE | NoUserInline -- User did not write any of INLINE/INLINABLE/NOINLINE -- e.g. in `defaultInlinePragma` or when created by CSE deriving( Eq, Data, Show ) -- Show needed for Lexer.x {- 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 = NoUserInline 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 = Inline or Inlineable, then the Id should have an InlineRule unfolding. If you want to know where InlinePragmas take effect: Look in DsBinds.makeCorePair Note [inl_inline and inl_act] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * inl_inline says what the user wrote: did she say INLINE, NOINLINE, INLINABLE, or nothing at all * inl_act says in what phases the unfolding is active or inactive E.g If you write INLINE[1] then inl_act will be set to ActiveAfter 1 If you write NOINLINE[1] then inl_act will be set to ActiveBefore 1 If you write NOINLINE[~1] then inl_act will be set to ActiveAfter 1 So note that inl_act does not say what pragma you wrote: it just expresses its consequences * inl_act just says when the unfolding is active; it doesn't say what to inline. If you say INLINE f, then f's inl_act will be AlwaysActive, but in addition f will get a "stable unfolding" with UnfoldingGuidance that tells the inliner to be pretty eager about it. 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.hs. -} isConLike :: RuleMatchInfo -> Bool isConLike ConLike = True isConLike _ = False isFunLike :: RuleMatchInfo -> Bool isFunLike FunLike = True isFunLike _ = False noUserInlineSpec :: InlineSpec -> Bool noUserInlineSpec NoUserInline = True noUserInlineSpec _ = False defaultInlinePragma, alwaysInlinePragma, neverInlinePragma, dfunInlinePragma :: InlinePragma defaultInlinePragma = InlinePragma { inl_src = SourceText "{-# INLINE" , inl_act = AlwaysActive , inl_rule = FunLike , inl_inline = NoUserInline , inl_sat = Nothing } alwaysInlinePragma = defaultInlinePragma { inl_inline = Inline } neverInlinePragma = defaultInlinePragma { inl_act = NeverActive } inlinePragmaSpec :: InlinePragma -> InlineSpec inlinePragmaSpec = inl_inline -- A DFun has an always-active inline activation so that -- exprIsConApp_maybe can "see" its unfolding -- (However, its actual Unfolding is a DFunUnfolding, which is -- never inlined other than via exprIsConApp_maybe.) dfunInlinePragma = defaultInlinePragma { inl_act = AlwaysActive , inl_rule = ConLike } isDefaultInlinePragma :: InlinePragma -> Bool isDefaultInlinePragma (InlinePragma { inl_act = activation , inl_rule = match_info , inl_inline = inline }) = noUserInlineSpec 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 -- INLINE or INLINABLE 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 = empty ppr NeverActive = brackets (text "~") ppr (ActiveBefore _ n) = brackets (char '~' <> int n) ppr (ActiveAfter _ n) = brackets (int n) instance Outputable RuleMatchInfo where ppr ConLike = text "CONLIKE" ppr FunLike = text "FUNLIKE" instance Outputable InlineSpec where ppr Inline = text "INLINE" ppr NoInline = text "NOINLINE" ppr Inlinable = text "INLINABLE" ppr NoUserInline = text "NOUSERINLINE" -- what is better? instance Outputable InlinePragma where ppr = pprInline pprInline :: InlinePragma -> SDoc pprInline = pprInline' True pprInlineDebug :: InlinePragma -> SDoc pprInlineDebug = pprInline' False pprInline' :: Bool -- True <=> do not display the inl_inline field -> InlinePragma -> SDoc pprInline' emptyInline (InlinePragma { inl_inline = inline, inl_act = activation , inl_rule = info, inl_sat = mb_arity }) = pp_inl inline <> pp_act inline activation <+> pp_sat <+> pp_info where pp_inl x = if emptyInline then empty else ppr x pp_act Inline AlwaysActive = empty pp_act NoInline NeverActive = empty pp_act _ act = ppr act pp_sat | Just ar <- mb_arity = parens (text "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 competesWith :: Activation -> Activation -> Bool -- See Note [Activation competition] competesWith NeverActive _ = False competesWith _ NeverActive = False competesWith AlwaysActive _ = True competesWith (ActiveBefore {}) AlwaysActive = True competesWith (ActiveBefore {}) (ActiveBefore {}) = True competesWith (ActiveBefore _ a) (ActiveAfter _ b) = a < b competesWith (ActiveAfter {}) AlwaysActive = False competesWith (ActiveAfter {}) (ActiveBefore {}) = False competesWith (ActiveAfter _ a) (ActiveAfter _ b) = a >= b {- Note [Competing activations] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sometimes a RULE and an inlining may compete, or two RULES. See Note [Rules and inlining/other rules] in Desugar. We say that act1 "competes with" act2 iff act1 is active in the phase when act2 *becomes* active NB: remember that phases count *down*: 2, 1, 0! It's too conservative to ensure that the two are never simultaneously active. For example, a rule might be always active, and an inlining might switch on in phase 2. We could switch off the rule, but it does no harm. -} isNeverActive, isAlwaysActive, isEarlyActive :: Activation -> Bool isNeverActive NeverActive = True isNeverActive _ = False isAlwaysActive AlwaysActive = True isAlwaysActive _ = False isEarlyActive AlwaysActive = True isEarlyActive (ActiveBefore {}) = True isEarlyActive _ = False -- | Integral Literal -- -- Used (instead of Integer) to represent negative zegative zero which is -- required for NegativeLiterals extension to correctly parse `-0::Double` -- as negative zero. See also #13211. data IntegralLit = IL { il_text :: SourceText , il_neg :: Bool -- See Note [Negative zero] , il_value :: Integer } deriving (Data, Show) mkIntegralLit :: Integral a => a -> IntegralLit mkIntegralLit i = IL { il_text = SourceText (show i_integer) , il_neg = i < 0 , il_value = i_integer } where i_integer :: Integer i_integer = toInteger i negateIntegralLit :: IntegralLit -> IntegralLit negateIntegralLit (IL text neg value) = case text of SourceText ('-':src) -> IL (SourceText src) False (negate value) SourceText src -> IL (SourceText ('-':src)) True (negate value) NoSourceText -> IL NoSourceText (not neg) (negate value) -- | Fractional Literal -- -- Used (instead of Rational) to represent exactly the floating point literal that we -- encountered in the user's source program. This allows us to pretty-print exactly what -- the user wrote, which is important e.g. for floating point numbers that can't represented -- as Doubles (we used to via Double for pretty-printing). See also #2245. data FractionalLit = FL { fl_text :: SourceText -- How the value was written in the source , fl_neg :: Bool -- See Note [Negative zero] , fl_value :: Rational -- Numeric value of the literal } deriving (Data, Show) -- The Show instance is required for the derived Lexer.x:Token instance when DEBUG is on mkFractionalLit :: Real a => a -> FractionalLit mkFractionalLit r = FL { fl_text = SourceText (show (realToFrac r::Double)) -- Converting to a Double here may technically lose -- precision (see #15502). We could alternatively -- convert to a Rational for the most accuracy, but -- it would cause Floats and Doubles to be displayed -- strangely, so we opt not to do this. (In contrast -- to mkIntegralLit, where we always convert to an -- Integer for the highest accuracy.) , fl_neg = r < 0 , fl_value = toRational r } negateFractionalLit :: FractionalLit -> FractionalLit negateFractionalLit (FL text neg value) = case text of SourceText ('-':src) -> FL (SourceText src) False value SourceText src -> FL (SourceText ('-':src)) True value NoSourceText -> FL NoSourceText (not neg) (negate value) integralFractionalLit :: Bool -> Integer -> FractionalLit integralFractionalLit neg i = FL { fl_text = SourceText (show i), fl_neg = neg, fl_value = fromInteger i } -- Comparison operations are needed when grouping literals -- for compiling pattern-matching (module MatchLit) instance Eq IntegralLit where (==) = (==) `on` il_value instance Ord IntegralLit where compare = compare `on` il_value instance Outputable IntegralLit where ppr (IL (SourceText src) _ _) = text src ppr (IL NoSourceText _ value) = text (show value) instance Eq FractionalLit where (==) = (==) `on` fl_value instance Ord FractionalLit where compare = compare `on` fl_value instance Outputable FractionalLit where ppr f = pprWithSourceText (fl_text f) (rational (fl_value f)) {- ************************************************************************ * * IntWithInf * * ************************************************************************ Represents an integer or positive infinity -} -- | An integer or infinity data IntWithInf = Int {-# UNPACK #-} !Int | Infinity deriving Eq -- | A representation of infinity infinity :: IntWithInf infinity = Infinity instance Ord IntWithInf where compare Infinity Infinity = EQ compare (Int _) Infinity = LT compare Infinity (Int _) = GT compare (Int a) (Int b) = a `compare` b instance Outputable IntWithInf where ppr Infinity = char '∞' ppr (Int n) = int n instance Num IntWithInf where (+) = plusWithInf (*) = mulWithInf abs Infinity = Infinity abs (Int n) = Int (abs n) signum Infinity = Int 1 signum (Int n) = Int (signum n) fromInteger = Int . fromInteger (-) = panic "subtracting IntWithInfs" intGtLimit :: Int -> IntWithInf -> Bool intGtLimit _ Infinity = False intGtLimit n (Int m) = n > m -- | Add two 'IntWithInf's plusWithInf :: IntWithInf -> IntWithInf -> IntWithInf plusWithInf Infinity _ = Infinity plusWithInf _ Infinity = Infinity plusWithInf (Int a) (Int b) = Int (a + b) -- | Multiply two 'IntWithInf's mulWithInf :: IntWithInf -> IntWithInf -> IntWithInf mulWithInf Infinity _ = Infinity mulWithInf _ Infinity = Infinity mulWithInf (Int a) (Int b) = Int (a * b) -- | Turn a positive number into an 'IntWithInf', where 0 represents infinity treatZeroAsInf :: Int -> IntWithInf treatZeroAsInf 0 = Infinity treatZeroAsInf n = Int n -- | Inject any integer into an 'IntWithInf' mkIntWithInf :: Int -> IntWithInf mkIntWithInf = Int data SpliceExplicitFlag = ExplicitSplice | -- ^ <=> $(f x y) ImplicitSplice -- ^ <=> f x y, i.e. a naked top level expression deriving Data {- ********************************************************************* * * Types vs Kinds * * ********************************************************************* -} -- | Flag to see whether we're type-checking terms or kind-checking types data TypeOrKind = TypeLevel | KindLevel deriving Eq instance Outputable TypeOrKind where ppr TypeLevel = text "TypeLevel" ppr KindLevel = text "KindLevel" isTypeLevel :: TypeOrKind -> Bool isTypeLevel TypeLevel = True isTypeLevel KindLevel = False isKindLevel :: TypeOrKind -> Bool isKindLevel TypeLevel = False isKindLevel KindLevel = True