{- (c) The University of Glasgow 2006 (c) The GRASP/AQUA Project, Glasgow University, 1998 \section[Literal]{@Literal@: Machine literals (unboxed, of course)} -} {-# LANGUAGE CPP, DeriveDataTypeable #-} module Literal ( -- * Main data type Literal(..) -- Exported to ParseIface -- ** Creating Literals , mkMachInt, mkMachWord , mkMachInt64, mkMachWord64 , mkMachFloat, mkMachDouble , mkMachChar, mkMachString , mkLitInteger -- ** Operations on Literals , literalType , hashLiteral , absentLiteralOf , pprLiteral -- ** Predicates on Literals and their contents , litIsDupable, litIsTrivial, litIsLifted , inIntRange, inWordRange, tARGET_MAX_INT, inCharRange , isZeroLit , litFitsInChar , litValue -- ** Coercions , word2IntLit, int2WordLit , narrow8IntLit, narrow16IntLit, narrow32IntLit , narrow8WordLit, narrow16WordLit, narrow32WordLit , char2IntLit, int2CharLit , float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit , nullAddrLit, float2DoubleLit, double2FloatLit ) where #include "HsVersions.h" import TysPrim import PrelNames import Type import TyCon import Outputable import FastString import BasicTypes import Binary import Constants import DynFlags import UniqFM import Util import Data.ByteString (ByteString) import Data.Int import Data.Ratio import Data.Word import Data.Char import Data.Data ( Data, Typeable ) import Numeric ( fromRat ) {- ************************************************************************ * * \subsection{Literals} * * ************************************************************************ -} -- | So-called 'Literal's are one of: -- -- * An unboxed (/machine/) literal ('MachInt', 'MachFloat', etc.), -- which is presumed to be surrounded by appropriate constructors -- (@Int#@, etc.), so that the overall thing makes sense. -- -- * The literal derived from the label mentioned in a \"foreign label\" -- declaration ('MachLabel') data Literal = ------------------ -- First the primitive guys MachChar Char -- ^ @Char#@ - at least 31 bits. Create with 'mkMachChar' | MachStr ByteString -- ^ A string-literal: stored and emitted -- UTF-8 encoded, we'll arrange to decode it -- at runtime. Also emitted with a @'\0'@ -- terminator. Create with 'mkMachString' | MachNullAddr -- ^ The @NULL@ pointer, the only pointer value -- that can be represented as a Literal. Create -- with 'nullAddrLit' | MachInt Integer -- ^ @Int#@ - at least @WORD_SIZE_IN_BITS@ bits. Create with 'mkMachInt' | MachInt64 Integer -- ^ @Int64#@ - at least 64 bits. Create with 'mkMachInt64' | MachWord Integer -- ^ @Word#@ - at least @WORD_SIZE_IN_BITS@ bits. Create with 'mkMachWord' | MachWord64 Integer -- ^ @Word64#@ - at least 64 bits. Create with 'mkMachWord64' | MachFloat Rational -- ^ @Float#@. Create with 'mkMachFloat' | MachDouble Rational -- ^ @Double#@. Create with 'mkMachDouble' | MachLabel FastString (Maybe Int) FunctionOrData -- ^ A label literal. Parameters: -- -- 1) The name of the symbol mentioned in the declaration -- -- 2) The size (in bytes) of the arguments -- the label expects. Only applicable with -- @stdcall@ labels. @Just x@ => @\@ will -- be appended to label name when emitting assembly. | LitInteger Integer Type -- ^ Integer literals -- See Note [Integer literals] deriving (Data, Typeable) {- Note [Integer literals] ~~~~~~~~~~~~~~~~~~~~~~~ An Integer literal is represented using, well, an Integer, to make it easier to write RULEs for them. They also contain the Integer type, so that e.g. literalType can return the right Type for them. They only get converted into real Core, mkInteger [c1, c2, .., cn] during the CorePrep phase, although TidyPgm looks ahead at what the core will be, so that it can see whether it involves CAFs. When we initally build an Integer literal, notably when deserialising it from an interface file (see the Binary instance below), we don't have convenient access to the mkInteger Id. So we just use an error thunk, and fill in the real Id when we do tcIfaceLit in TcIface. Binary instance -} instance Binary Literal where put_ bh (MachChar aa) = do putByte bh 0; put_ bh aa put_ bh (MachStr ab) = do putByte bh 1; put_ bh ab put_ bh (MachNullAddr) = do putByte bh 2 put_ bh (MachInt ad) = do putByte bh 3; put_ bh ad put_ bh (MachInt64 ae) = do putByte bh 4; put_ bh ae put_ bh (MachWord af) = do putByte bh 5; put_ bh af put_ bh (MachWord64 ag) = do putByte bh 6; put_ bh ag put_ bh (MachFloat ah) = do putByte bh 7; put_ bh ah put_ bh (MachDouble ai) = do putByte bh 8; put_ bh ai put_ bh (MachLabel aj mb fod) = do putByte bh 9 put_ bh aj put_ bh mb put_ bh fod put_ bh (LitInteger i _) = do putByte bh 10; put_ bh i get bh = do h <- getByte bh case h of 0 -> do aa <- get bh return (MachChar aa) 1 -> do ab <- get bh return (MachStr ab) 2 -> do return (MachNullAddr) 3 -> do ad <- get bh return (MachInt ad) 4 -> do ae <- get bh return (MachInt64 ae) 5 -> do af <- get bh return (MachWord af) 6 -> do ag <- get bh return (MachWord64 ag) 7 -> do ah <- get bh return (MachFloat ah) 8 -> do ai <- get bh return (MachDouble ai) 9 -> do aj <- get bh mb <- get bh fod <- get bh return (MachLabel aj mb fod) _ -> do i <- get bh -- See Note [Integer literals] return $ mkLitInteger i (panic "Evaluated the place holder for mkInteger") instance Outputable Literal where ppr lit = pprLiteral (\d -> d) lit instance Eq Literal where a == b = case (a `compare` b) of { EQ -> True; _ -> False } a /= b = case (a `compare` b) of { EQ -> False; _ -> True } instance Ord Literal where a <= b = case (a `compare` b) of { LT -> True; EQ -> True; GT -> False } a < b = case (a `compare` b) of { LT -> True; EQ -> False; GT -> False } a >= b = case (a `compare` b) of { LT -> False; EQ -> True; GT -> True } a > b = case (a `compare` b) of { LT -> False; EQ -> False; GT -> True } compare a b = cmpLit a b {- Construction ~~~~~~~~~~~~ -} -- | Creates a 'Literal' of type @Int#@ mkMachInt :: DynFlags -> Integer -> Literal mkMachInt dflags x = ASSERT2( inIntRange dflags x, integer x ) MachInt x -- | Creates a 'Literal' of type @Word#@ mkMachWord :: DynFlags -> Integer -> Literal mkMachWord dflags x = ASSERT2( inWordRange dflags x, integer x ) MachWord x -- | Creates a 'Literal' of type @Int64#@ mkMachInt64 :: Integer -> Literal mkMachInt64 x = MachInt64 x -- | Creates a 'Literal' of type @Word64#@ mkMachWord64 :: Integer -> Literal mkMachWord64 x = MachWord64 x -- | Creates a 'Literal' of type @Float#@ mkMachFloat :: Rational -> Literal mkMachFloat = MachFloat -- | Creates a 'Literal' of type @Double#@ mkMachDouble :: Rational -> Literal mkMachDouble = MachDouble -- | Creates a 'Literal' of type @Char#@ mkMachChar :: Char -> Literal mkMachChar = MachChar -- | Creates a 'Literal' of type @Addr#@, which is appropriate for passing to -- e.g. some of the \"error\" functions in GHC.Err such as @GHC.Err.runtimeError@ mkMachString :: String -> Literal -- stored UTF-8 encoded mkMachString s = MachStr (fastStringToByteString $ mkFastString s) mkLitInteger :: Integer -> Type -> Literal mkLitInteger = LitInteger inIntRange, inWordRange :: DynFlags -> Integer -> Bool inIntRange dflags x = x >= tARGET_MIN_INT dflags && x <= tARGET_MAX_INT dflags inWordRange dflags x = x >= 0 && x <= tARGET_MAX_WORD dflags inCharRange :: Char -> Bool inCharRange c = c >= '\0' && c <= chr tARGET_MAX_CHAR -- | Tests whether the literal represents a zero of whatever type it is isZeroLit :: Literal -> Bool isZeroLit (MachInt 0) = True isZeroLit (MachInt64 0) = True isZeroLit (MachWord 0) = True isZeroLit (MachWord64 0) = True isZeroLit (MachFloat 0) = True isZeroLit (MachDouble 0) = True isZeroLit _ = False -- | Returns the 'Integer' contained in the 'Literal', for when that makes -- sense, i.e. for 'Char', 'Int', 'Word' and 'LitInteger'. litValue :: Literal -> Integer litValue (MachChar c) = toInteger $ ord c litValue (MachInt i) = i litValue (MachInt64 i) = i litValue (MachWord i) = i litValue (MachWord64 i) = i litValue (LitInteger i _) = i litValue l = pprPanic "litValue" (ppr l) {- Coercions ~~~~~~~~~ -} narrow8IntLit, narrow16IntLit, narrow32IntLit, narrow8WordLit, narrow16WordLit, narrow32WordLit, char2IntLit, int2CharLit, float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit, float2DoubleLit, double2FloatLit :: Literal -> Literal word2IntLit, int2WordLit :: DynFlags -> Literal -> Literal word2IntLit dflags (MachWord w) | w > tARGET_MAX_INT dflags = MachInt (w - tARGET_MAX_WORD dflags - 1) | otherwise = MachInt w word2IntLit _ l = pprPanic "word2IntLit" (ppr l) int2WordLit dflags (MachInt i) | i < 0 = MachWord (1 + tARGET_MAX_WORD dflags + i) -- (-1) ---> tARGET_MAX_WORD | otherwise = MachWord i int2WordLit _ l = pprPanic "int2WordLit" (ppr l) narrow8IntLit (MachInt i) = MachInt (toInteger (fromInteger i :: Int8)) narrow8IntLit l = pprPanic "narrow8IntLit" (ppr l) narrow16IntLit (MachInt i) = MachInt (toInteger (fromInteger i :: Int16)) narrow16IntLit l = pprPanic "narrow16IntLit" (ppr l) narrow32IntLit (MachInt i) = MachInt (toInteger (fromInteger i :: Int32)) narrow32IntLit l = pprPanic "narrow32IntLit" (ppr l) narrow8WordLit (MachWord w) = MachWord (toInteger (fromInteger w :: Word8)) narrow8WordLit l = pprPanic "narrow8WordLit" (ppr l) narrow16WordLit (MachWord w) = MachWord (toInteger (fromInteger w :: Word16)) narrow16WordLit l = pprPanic "narrow16WordLit" (ppr l) narrow32WordLit (MachWord w) = MachWord (toInteger (fromInteger w :: Word32)) narrow32WordLit l = pprPanic "narrow32WordLit" (ppr l) char2IntLit (MachChar c) = MachInt (toInteger (ord c)) char2IntLit l = pprPanic "char2IntLit" (ppr l) int2CharLit (MachInt i) = MachChar (chr (fromInteger i)) int2CharLit l = pprPanic "int2CharLit" (ppr l) float2IntLit (MachFloat f) = MachInt (truncate f) float2IntLit l = pprPanic "float2IntLit" (ppr l) int2FloatLit (MachInt i) = MachFloat (fromInteger i) int2FloatLit l = pprPanic "int2FloatLit" (ppr l) double2IntLit (MachDouble f) = MachInt (truncate f) double2IntLit l = pprPanic "double2IntLit" (ppr l) int2DoubleLit (MachInt i) = MachDouble (fromInteger i) int2DoubleLit l = pprPanic "int2DoubleLit" (ppr l) float2DoubleLit (MachFloat f) = MachDouble f float2DoubleLit l = pprPanic "float2DoubleLit" (ppr l) double2FloatLit (MachDouble d) = MachFloat d double2FloatLit l = pprPanic "double2FloatLit" (ppr l) nullAddrLit :: Literal nullAddrLit = MachNullAddr {- Predicates ~~~~~~~~~~ -} -- | True if there is absolutely no penalty to duplicating the literal. -- False principally of strings litIsTrivial :: Literal -> Bool -- c.f. CoreUtils.exprIsTrivial litIsTrivial (MachStr _) = False litIsTrivial (LitInteger {}) = False litIsTrivial _ = True -- | True if code space does not go bad if we duplicate this literal -- Currently we treat it just like 'litIsTrivial' litIsDupable :: DynFlags -> Literal -> Bool -- c.f. CoreUtils.exprIsDupable litIsDupable _ (MachStr _) = False litIsDupable dflags (LitInteger i _) = inIntRange dflags i litIsDupable _ _ = True litFitsInChar :: Literal -> Bool litFitsInChar (MachInt i) = i >= toInteger (ord minBound) && i <= toInteger (ord maxBound) litFitsInChar _ = False litIsLifted :: Literal -> Bool litIsLifted (LitInteger {}) = True litIsLifted _ = False {- Types ~~~~~ -} -- | Find the Haskell 'Type' the literal occupies literalType :: Literal -> Type literalType MachNullAddr = addrPrimTy literalType (MachChar _) = charPrimTy literalType (MachStr _) = addrPrimTy literalType (MachInt _) = intPrimTy literalType (MachWord _) = wordPrimTy literalType (MachInt64 _) = int64PrimTy literalType (MachWord64 _) = word64PrimTy literalType (MachFloat _) = floatPrimTy literalType (MachDouble _) = doublePrimTy literalType (MachLabel _ _ _) = addrPrimTy literalType (LitInteger _ t) = t absentLiteralOf :: TyCon -> Maybe Literal -- Return a literal of the appropriate primtive -- TyCon, to use as a placeholder when it doesn't matter absentLiteralOf tc = lookupUFM absent_lits (tyConName tc) absent_lits :: UniqFM Literal absent_lits = listToUFM [ (addrPrimTyConKey, MachNullAddr) , (charPrimTyConKey, MachChar 'x') , (intPrimTyConKey, MachInt 0) , (int64PrimTyConKey, MachInt64 0) , (floatPrimTyConKey, MachFloat 0) , (doublePrimTyConKey, MachDouble 0) , (wordPrimTyConKey, MachWord 0) , (word64PrimTyConKey, MachWord64 0) ] {- Comparison ~~~~~~~~~~ -} cmpLit :: Literal -> Literal -> Ordering cmpLit (MachChar a) (MachChar b) = a `compare` b cmpLit (MachStr a) (MachStr b) = a `compare` b cmpLit (MachNullAddr) (MachNullAddr) = EQ cmpLit (MachInt a) (MachInt b) = a `compare` b cmpLit (MachWord a) (MachWord b) = a `compare` b cmpLit (MachInt64 a) (MachInt64 b) = a `compare` b cmpLit (MachWord64 a) (MachWord64 b) = a `compare` b cmpLit (MachFloat a) (MachFloat b) = a `compare` b cmpLit (MachDouble a) (MachDouble b) = a `compare` b cmpLit (MachLabel a _ _) (MachLabel b _ _) = a `compare` b cmpLit (LitInteger a _) (LitInteger b _) = a `compare` b cmpLit lit1 lit2 | litTag lit1 < litTag lit2 = LT | otherwise = GT litTag :: Literal -> Int litTag (MachChar _) = 1 litTag (MachStr _) = 2 litTag (MachNullAddr) = 3 litTag (MachInt _) = 4 litTag (MachWord _) = 5 litTag (MachInt64 _) = 6 litTag (MachWord64 _) = 7 litTag (MachFloat _) = 8 litTag (MachDouble _) = 9 litTag (MachLabel _ _ _) = 10 litTag (LitInteger {}) = 11 {- Printing ~~~~~~~~ * See Note [Printing of literals in Core] -} pprLiteral :: (SDoc -> SDoc) -> Literal -> SDoc pprLiteral _ (MachChar c) = pprPrimChar c pprLiteral _ (MachStr s) = pprHsBytes s pprLiteral _ (MachNullAddr) = text "__NULL" pprLiteral _ (MachInt i) = pprPrimInt i pprLiteral _ (MachInt64 i) = pprPrimInt64 i pprLiteral _ (MachWord w) = pprPrimWord w pprLiteral _ (MachWord64 w) = pprPrimWord64 w pprLiteral _ (MachFloat f) = float (fromRat f) <> primFloatSuffix pprLiteral _ (MachDouble d) = double (fromRat d) <> primDoubleSuffix pprLiteral add_par (LitInteger i _) = pprIntegerVal add_par i pprLiteral add_par (MachLabel l mb fod) = add_par (text "__label" <+> b <+> ppr fod) where b = case mb of Nothing -> pprHsString l Just x -> doubleQuotes (text (unpackFS l ++ '@':show x)) pprIntegerVal :: (SDoc -> SDoc) -> Integer -> SDoc -- See Note [Printing of literals in Core]. pprIntegerVal add_par i | i < 0 = add_par (integer i) | otherwise = integer i {- Note [Printing of literals in Core] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The function `add_par` is used to wrap parenthesis around negative integers (`LitInteger`) and labels (`MachLabel`), if they occur in a context requiring an atomic thing (for example function application). Although not all Core literals would be valid Haskell, we are trying to stay as close as possible to Haskell syntax in the printing of Core, to make it easier for a Haskell user to read Core. To that end: * We do print parenthesis around negative `LitInteger`, because we print `LitInteger` using plain number literals (no prefix or suffix), and plain number literals in Haskell require parenthesis in contexts like function application (i.e. `1 - -1` is not valid Haskell). * We don't print parenthesis around other (negative) literals, because they aren't needed in GHC/Haskell either (i.e. `1# -# -1#` is accepted by GHC's parser). Literal Output Output if context requires an atom (if different) ------- ------- ---------------------- MachChar 'a'# MachStr "aaa"# MachNullAddr "__NULL" MachInt -1# MachInt64 -1L# MachWord 1## MachWord64 1L## MachFloat -1.0# MachDouble -1.0## LitInteger -1 (-1) MachLabel "__label" ... ("__label" ...) -} {- ************************************************************************ * * \subsection{Hashing} * * ************************************************************************ Hash values should be zero or a positive integer. No negatives please. (They mess up the UniqFM for some reason.) -} hashLiteral :: Literal -> Int hashLiteral (MachChar c) = ord c + 1000 -- Keep it out of range of common ints hashLiteral (MachStr s) = hashByteString s hashLiteral (MachNullAddr) = 0 hashLiteral (MachInt i) = hashInteger i hashLiteral (MachInt64 i) = hashInteger i hashLiteral (MachWord i) = hashInteger i hashLiteral (MachWord64 i) = hashInteger i hashLiteral (MachFloat r) = hashRational r hashLiteral (MachDouble r) = hashRational r hashLiteral (MachLabel s _ _) = hashFS s hashLiteral (LitInteger i _) = hashInteger i hashRational :: Rational -> Int hashRational r = hashInteger (numerator r) hashInteger :: Integer -> Int hashInteger i = 1 + abs (fromInteger (i `rem` 10000)) -- The 1+ is to avoid zero, which is a Bad Number -- since we use * to combine hash values hashFS :: FastString -> Int hashFS s = uniqueOfFS s