{-
(c) The University of Glasgow 2006
(c) The GRASP/AQUA Project, Glasgow University, 1998

\section[Literal]{@Literal@: literals}
-}

{-# LANGUAGE CPP, DeriveDataTypeable, ScopedTypeVariables #-}
{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}

module GHC.Types.Literal
        (
        -- * Main data type
          Literal(..)           -- Exported to ParseIface
        , LitNumType(..)

        -- ** Creating Literals
        , mkLitInt, mkLitIntWrap, mkLitIntWrapC, mkLitIntUnchecked
        , mkLitWord, mkLitWordWrap, mkLitWordWrapC
        , mkLitInt64, mkLitInt64Wrap
        , mkLitWord64, mkLitWord64Wrap
        , mkLitFloat, mkLitDouble
        , mkLitChar, mkLitString
        , mkLitInteger, mkLitNatural
        , mkLitNumber, mkLitNumberWrap

        -- ** Operations on Literals
        , literalType
        , absentLiteralOf
        , pprLiteral
        , litNumIsSigned
        , litNumCheckRange

        -- ** Predicates on Literals and their contents
        , litIsDupable, litIsTrivial, litIsLifted
        , inCharRange
        , isZeroLit
        , litFitsInChar
        , litValue, isLitValue, isLitValue_maybe, mapLitValue

        -- ** Coercions
        , word2IntLit, int2WordLit
        , narrowLit
        , narrow8IntLit, narrow16IntLit, narrow32IntLit
        , narrow8WordLit, narrow16WordLit, narrow32WordLit
        , char2IntLit, int2CharLit
        , float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit
        , nullAddrLit, rubbishLit, float2DoubleLit, double2FloatLit
        ) where

#include "HsVersions.h"

import GHC.Prelude

import GHC.Builtin.Types.Prim
import {-# SOURCE #-} GHC.Builtin.Types
import GHC.Builtin.Names
import GHC.Core.Type
import GHC.Core.TyCon
import GHC.Utils.Outputable
import GHC.Data.FastString
import GHC.Types.Basic
import GHC.Utils.Binary
import GHC.Settings.Constants
import GHC.Platform
import GHC.Types.Unique.FM
import GHC.Utils.Misc

import Data.ByteString (ByteString)
import Data.Int
import Data.Word
import Data.Char
import Data.Maybe ( isJust )
import Data.Data ( Data )
import Data.Proxy
import Numeric ( fromRat )

{-
************************************************************************
*                                                                      *
\subsection{Literals}
*                                                                      *
************************************************************************
-}

-- | So-called 'Literal's are one of:
--
-- * An unboxed numeric literal or floating-point literal which is presumed
--   to be surrounded by appropriate constructors (@Int#@, etc.), so that
--   the overall thing makes sense.
--
--   We maintain the invariant that the 'Integer' in the 'LitNumber'
--   constructor is actually in the (possibly target-dependent) range.
--   The mkLit{Int,Word}*Wrap smart constructors ensure this by applying
--   the target machine's wrapping semantics. Use these in situations
--   where you know the wrapping semantics are correct.
--
-- * The literal derived from the label mentioned in a \"foreign label\"
--   declaration ('LitLabel')
--
-- * A 'LitRubbish' to be used in place of values of 'UnliftedRep'
--   (i.e. 'MutVar#') when the value is never used.
--
-- * A character
-- * A string
-- * The NULL pointer
--
data Literal
  = LitChar    Char             -- ^ @Char#@ - at least 31 bits. Create with
                                -- 'mkLitChar'

  | LitNumber !LitNumType !Integer
                                -- ^ Any numeric literal that can be
                                -- internally represented with an Integer.

  | LitString !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 'mkLitString'

  | LitNullAddr                 -- ^ The @NULL@ pointer, the only pointer value
                                -- that can be represented as a Literal. Create
                                -- with 'nullAddrLit'

  | LitRubbish                  -- ^ A nonsense value, used when an unlifted
                                -- binding is absent and has type
                                -- @forall (a :: 'TYPE' 'UnliftedRep'). a@.
                                -- May be lowered by code-gen to any possible
                                -- value. Also see Note [Rubbish literals]

  | LitFloat   Rational         -- ^ @Float#@. Create with 'mkLitFloat'
  | LitDouble  Rational         -- ^ @Double#@. Create with 'mkLitDouble'

  | LitLabel   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@ => @\<x\>@ will
                                --    be appended to label name when emitting
                                --    assembly.
                                --
                                -- 3) Flag indicating whether the symbol
                                --    references a function or a data
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-- | Numeric literal type
data LitNumType
  = LitNumInteger -- ^ @Integer@ (see Note [BigNum literals])
  | LitNumNatural -- ^ @Natural@ (see Note [BigNum literals])
  | LitNumInt     -- ^ @Int#@ - according to target machine
  | LitNumInt64   -- ^ @Int64#@ - exactly 64 bits
  | LitNumWord    -- ^ @Word#@ - according to target machine
  | LitNumWord64  -- ^ @Word64#@ - exactly 64 bits
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-- | Indicate if a numeric literal type supports negative numbers
litNumIsSigned :: LitNumType -> Bool
litNumIsSigned :: LitNumType -> Bool
litNumIsSigned LitNumType
nt = case LitNumType
nt of
  LitNumType
LitNumInteger -> Bool
True
  LitNumType
LitNumNatural -> Bool
False
  LitNumType
LitNumInt     -> Bool
True
  LitNumType
LitNumInt64   -> Bool
True
  LitNumType
LitNumWord    -> Bool
False
  LitNumType
LitNumWord64  -> Bool
False

{-
Note [BigNum literals]
~~~~~~~~~~~~~~~~~~~~~~

GHC supports 2 kinds of arbitrary precision integers (a.k.a BigNum):

   * Natural: natural represented as a Word# or as a BigNat

   * Integer: integer represented a an Int# or as a BigNat (Integer's
   constructors indicate the sign)

BigNum literal instances are removed from Core during the CorePrep phase. They
are replaced with expression to build them at runtime from machine literals
(Word#, Int#, etc.) or from a list of Word#s.

Note [String literals]
~~~~~~~~~~~~~~~~~~~~~~

String literals are UTF-8 encoded and stored into ByteStrings in the following
ASTs: Haskell, Core, Stg, Cmm. TH can also emit ByteString based string literals
with the BytesPrimL constructor (see #14741).

It wasn't true before as [Word8] was used in Cmm AST and in TH which was quite
bad for performance with large strings (see #16198 and #14741).

To include string literals into output objects, the assembler code generator has
to embed the UTF-8 encoded binary blob. See Note [Embedding large binary blobs]
for more details.

-}

instance Binary LitNumType where
   put_ :: BinHandle -> LitNumType -> IO ()
put_ BinHandle
bh LitNumType
numTyp = BinHandle -> Word8 -> IO ()
putByte BinHandle
bh (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (LitNumType -> Int
forall a. Enum a => a -> Int
fromEnum LitNumType
numTyp))
   get :: BinHandle -> IO LitNumType
get BinHandle
bh = do
      Word8
h <- BinHandle -> IO Word8
getByte BinHandle
bh
      LitNumType -> IO LitNumType
forall (m :: * -> *) a. Monad m => a -> m a
return (Int -> LitNumType
forall a. Enum a => Int -> a
toEnum (Word8 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word8
h))

instance Binary Literal where
    put_ :: BinHandle -> Literal -> IO ()
put_ BinHandle
bh (LitChar Char
aa)     = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
0; BinHandle -> Char -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh Char
aa
    put_ BinHandle
bh (LitString ByteString
ab)   = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
1; BinHandle -> ByteString -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh ByteString
ab
    put_ BinHandle
bh (Literal
LitNullAddr)    = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
2
    put_ BinHandle
bh (LitFloat Rational
ah)    = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
3; BinHandle -> Rational -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh Rational
ah
    put_ BinHandle
bh (LitDouble Rational
ai)   = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
4; BinHandle -> Rational -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh Rational
ai
    put_ BinHandle
bh (LitLabel FastString
aj Maybe Int
mb FunctionOrData
fod)
        = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
5
             BinHandle -> FastString -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh FastString
aj
             BinHandle -> Maybe Int -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh Maybe Int
mb
             BinHandle -> FunctionOrData -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh FunctionOrData
fod
    put_ BinHandle
bh (LitNumber LitNumType
nt Integer
i)
        = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
6
             BinHandle -> LitNumType -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh LitNumType
nt
             BinHandle -> Integer -> IO ()
forall a. Binary a => BinHandle -> a -> IO ()
put_ BinHandle
bh Integer
i
    put_ BinHandle
bh (Literal
LitRubbish)     = do BinHandle -> Word8 -> IO ()
putByte BinHandle
bh Word8
7
    get :: BinHandle -> IO Literal
get BinHandle
bh = do
            Word8
h <- BinHandle -> IO Word8
getByte BinHandle
bh
            case Word8
h of
              Word8
0 -> do
                    Char
aa <- BinHandle -> IO Char
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (Char -> Literal
LitChar Char
aa)
              Word8
1 -> do
                    ByteString
ab <- BinHandle -> IO ByteString
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (ByteString -> Literal
LitString ByteString
ab)
              Word8
2 -> do
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (Literal
LitNullAddr)
              Word8
3 -> do
                    Rational
ah <- BinHandle -> IO Rational
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (Rational -> Literal
LitFloat Rational
ah)
              Word8
4 -> do
                    Rational
ai <- BinHandle -> IO Rational
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (Rational -> Literal
LitDouble Rational
ai)
              Word8
5 -> do
                    FastString
aj <- BinHandle -> IO FastString
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Maybe Int
mb <- BinHandle -> IO (Maybe Int)
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    FunctionOrData
fod <- BinHandle -> IO FunctionOrData
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (FastString -> Maybe Int -> FunctionOrData -> Literal
LitLabel FastString
aj Maybe Int
mb FunctionOrData
fod)
              Word8
6 -> do
                    LitNumType
nt <- BinHandle -> IO LitNumType
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Integer
i  <- BinHandle -> IO Integer
forall a. Binary a => BinHandle -> IO a
get BinHandle
bh
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (LitNumType -> Integer -> Literal
LitNumber LitNumType
nt Integer
i)
              Word8
_ -> do
                    Literal -> IO Literal
forall (m :: * -> *) a. Monad m => a -> m a
return (Literal
LitRubbish)

instance Outputable Literal where
    ppr :: Literal -> SDoc
ppr = (SDoc -> SDoc) -> Literal -> SDoc
pprLiteral SDoc -> SDoc
forall a. a -> a
id

instance Eq Literal where
    Literal
a == :: Literal -> Literal -> Bool
== Literal
b = Literal -> Literal -> Ordering
forall a. Ord a => a -> a -> Ordering
compare Literal
a Literal
b Ordering -> Ordering -> Bool
forall a. Eq a => a -> a -> Bool
== Ordering
EQ

-- | Needed for the @Ord@ instance of 'AltCon', which in turn is needed in
-- 'GHC.Data.TrieMap.CoreMap'.
instance Ord Literal where
    compare :: Literal -> Literal -> Ordering
compare = Literal -> Literal -> Ordering
cmpLit

{-
        Construction
        ~~~~~~~~~~~~
-}

{- Note [Word/Int underflow/overflow]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
According to the Haskell Report 2010 (Sections 18.1 and 23.1 about signed and
unsigned integral types): "All arithmetic is performed modulo 2^n, where n is
the number of bits in the type."

GHC stores Word# and Int# constant values as Integer. Core optimizations such
as constant folding must ensure that the Integer value remains in the valid
target Word/Int range (see #13172). The following functions are used to
ensure this.

Note that we *don't* warn the user about overflow. It's not done at runtime
either, and compilation of completely harmless things like
   ((124076834 :: Word32) + (2147483647 :: Word32))
doesn't yield a warning. Instead we simply squash the value into the *target*
Int/Word range.
-}

-- | Wrap a literal number according to its type
wrapLitNumber :: Platform -> Literal -> Literal
wrapLitNumber :: Platform -> Literal -> Literal
wrapLitNumber Platform
platform v :: Literal
v@(LitNumber LitNumType
nt Integer
i) = case LitNumType
nt of
  LitNumType
LitNumInt -> case Platform -> PlatformWordSize
platformWordSize Platform
platform of
    PlatformWordSize
PW4 -> LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (Int32 -> Integer
forall a. Integral a => a -> Integer
toInteger (Integer -> Int32
forall a b. (Integral a, Num b) => a -> b
fromIntegral Integer
i :: Int32))
    PlatformWordSize
PW8 -> LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (Int64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Integer -> Int64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Integer
i :: Int64))
  LitNumType
LitNumWord -> case Platform -> PlatformWordSize
platformWordSize Platform
platform of
    PlatformWordSize
PW4 -> LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (Word32 -> Integer
forall a. Integral a => a -> Integer
toInteger (Integer -> Word32
forall a b. (Integral a, Num b) => a -> b
fromIntegral Integer
i :: Word32))
    PlatformWordSize
PW8 -> LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (Word64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Integer -> Word64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Integer
i :: Word64))
  LitNumType
LitNumInt64   -> LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (Int64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Integer -> Int64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Integer
i :: Int64))
  LitNumType
LitNumWord64  -> LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (Word64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Integer -> Word64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Integer
i :: Word64))
  LitNumType
LitNumInteger -> Literal
v
  LitNumType
LitNumNatural -> Literal
v
wrapLitNumber Platform
_ Literal
x = Literal
x

-- | Create a numeric 'Literal' of the given type
mkLitNumberWrap :: Platform -> LitNumType -> Integer -> Literal
mkLitNumberWrap :: Platform -> LitNumType -> Integer -> Literal
mkLitNumberWrap Platform
platform LitNumType
nt Integer
i = Platform -> Literal -> Literal
wrapLitNumber Platform
platform (LitNumType -> Integer -> Literal
LitNumber LitNumType
nt Integer
i)

-- | Check that a given number is in the range of a numeric literal
litNumCheckRange :: Platform -> LitNumType -> Integer -> Bool
litNumCheckRange :: Platform -> LitNumType -> Integer -> Bool
litNumCheckRange Platform
platform LitNumType
nt Integer
i = case LitNumType
nt of
     LitNumType
LitNumInt     -> Platform -> Integer -> Bool
platformInIntRange Platform
platform Integer
i
     LitNumType
LitNumWord    -> Platform -> Integer -> Bool
platformInWordRange Platform
platform Integer
i
     LitNumType
LitNumInt64   -> Integer -> Bool
inInt64Range Integer
i
     LitNumType
LitNumWord64  -> Integer -> Bool
inWord64Range Integer
i
     LitNumType
LitNumNatural -> Integer
i Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
>= Integer
0
     LitNumType
LitNumInteger -> Bool
True

-- | Create a numeric 'Literal' of the given type
mkLitNumber :: Platform -> LitNumType -> Integer -> Literal
mkLitNumber :: Platform -> LitNumType -> Integer -> Literal
mkLitNumber Platform
platform LitNumType
nt Integer
i =
  ASSERT2(litNumCheckRange platform nt i, integer i)
  (LitNumType -> Integer -> Literal
LitNumber LitNumType
nt Integer
i)

-- | Creates a 'Literal' of type @Int#@
mkLitInt :: Platform -> Integer -> Literal
mkLitInt :: Platform -> Integer -> Literal
mkLitInt Platform
platform Integer
x = ASSERT2( platformInIntRange platform x,  integer x )
                       (Integer -> Literal
mkLitIntUnchecked Integer
x)

-- | Creates a 'Literal' of type @Int#@.
--   If the argument is out of the (target-dependent) range, it is wrapped.
--   See Note [Word/Int underflow/overflow]
mkLitIntWrap :: Platform -> Integer -> Literal
mkLitIntWrap :: Platform -> Integer -> Literal
mkLitIntWrap Platform
platform Integer
i = Platform -> Literal -> Literal
wrapLitNumber Platform
platform (Literal -> Literal) -> Literal -> Literal
forall a b. (a -> b) -> a -> b
$ Integer -> Literal
mkLitIntUnchecked Integer
i

-- | Creates a 'Literal' of type @Int#@ without checking its range.
mkLitIntUnchecked :: Integer -> Literal
mkLitIntUnchecked :: Integer -> Literal
mkLitIntUnchecked Integer
i = LitNumType -> Integer -> Literal
LitNumber LitNumType
LitNumInt Integer
i

-- | Creates a 'Literal' of type @Int#@, as well as a 'Bool'ean flag indicating
--   overflow. That is, if the argument is out of the (target-dependent) range
--   the argument is wrapped and the overflow flag will be set.
--   See Note [Word/Int underflow/overflow]
mkLitIntWrapC :: Platform -> Integer -> (Literal, Bool)
mkLitIntWrapC :: Platform -> Integer -> (Literal, Bool)
mkLitIntWrapC Platform
platform Integer
i = (Literal
n, Integer
i Integer -> Integer -> Bool
forall a. Eq a => a -> a -> Bool
/= Integer
i')
  where
    n :: Literal
n@(LitNumber LitNumType
_ Integer
i') = Platform -> Integer -> Literal
mkLitIntWrap Platform
platform Integer
i

-- | Creates a 'Literal' of type @Word#@
mkLitWord :: Platform -> Integer -> Literal
mkLitWord :: Platform -> Integer -> Literal
mkLitWord Platform
platform Integer
x = ASSERT2( platformInWordRange platform x, integer x )
                        (Integer -> Literal
mkLitWordUnchecked Integer
x)

-- | Creates a 'Literal' of type @Word#@.
--   If the argument is out of the (target-dependent) range, it is wrapped.
--   See Note [Word/Int underflow/overflow]
mkLitWordWrap :: Platform -> Integer -> Literal
mkLitWordWrap :: Platform -> Integer -> Literal
mkLitWordWrap Platform
platform Integer
i = Platform -> Literal -> Literal
wrapLitNumber Platform
platform (Literal -> Literal) -> Literal -> Literal
forall a b. (a -> b) -> a -> b
$ Integer -> Literal
mkLitWordUnchecked Integer
i

-- | Creates a 'Literal' of type @Word#@ without checking its range.
mkLitWordUnchecked :: Integer -> Literal
mkLitWordUnchecked :: Integer -> Literal
mkLitWordUnchecked Integer
i = LitNumType -> Integer -> Literal
LitNumber LitNumType
LitNumWord Integer
i

-- | Creates a 'Literal' of type @Word#@, as well as a 'Bool'ean flag indicating
--   carry. That is, if the argument is out of the (target-dependent) range
--   the argument is wrapped and the carry flag will be set.
--   See Note [Word/Int underflow/overflow]
mkLitWordWrapC :: Platform -> Integer -> (Literal, Bool)
mkLitWordWrapC :: Platform -> Integer -> (Literal, Bool)
mkLitWordWrapC Platform
platform Integer
i = (Literal
n, Integer
i Integer -> Integer -> Bool
forall a. Eq a => a -> a -> Bool
/= Integer
i')
  where
    n :: Literal
n@(LitNumber LitNumType
_ Integer
i') = Platform -> Integer -> Literal
mkLitWordWrap Platform
platform Integer
i

-- | Creates a 'Literal' of type @Int64#@
mkLitInt64 :: Integer -> Literal
mkLitInt64 :: Integer -> Literal
mkLitInt64  Integer
x = ASSERT2( inInt64Range x, integer x ) (mkLitInt64Unchecked x)

-- | Creates a 'Literal' of type @Int64#@.
--   If the argument is out of the range, it is wrapped.
mkLitInt64Wrap :: Platform -> Integer -> Literal
mkLitInt64Wrap :: Platform -> Integer -> Literal
mkLitInt64Wrap Platform
platform Integer
i = Platform -> Literal -> Literal
wrapLitNumber Platform
platform (Literal -> Literal) -> Literal -> Literal
forall a b. (a -> b) -> a -> b
$ Integer -> Literal
mkLitInt64Unchecked Integer
i

-- | Creates a 'Literal' of type @Int64#@ without checking its range.
mkLitInt64Unchecked :: Integer -> Literal
mkLitInt64Unchecked :: Integer -> Literal
mkLitInt64Unchecked Integer
i = LitNumType -> Integer -> Literal
LitNumber LitNumType
LitNumInt64 Integer
i

-- | Creates a 'Literal' of type @Word64#@
mkLitWord64 :: Integer -> Literal
mkLitWord64 :: Integer -> Literal
mkLitWord64 Integer
x = ASSERT2( inWord64Range x, integer x ) (mkLitWord64Unchecked x)

-- | Creates a 'Literal' of type @Word64#@.
--   If the argument is out of the range, it is wrapped.
mkLitWord64Wrap :: Platform -> Integer -> Literal
mkLitWord64Wrap :: Platform -> Integer -> Literal
mkLitWord64Wrap Platform
platform Integer
i = Platform -> Literal -> Literal
wrapLitNumber Platform
platform (Literal -> Literal) -> Literal -> Literal
forall a b. (a -> b) -> a -> b
$ Integer -> Literal
mkLitWord64Unchecked Integer
i

-- | Creates a 'Literal' of type @Word64#@ without checking its range.
mkLitWord64Unchecked :: Integer -> Literal
mkLitWord64Unchecked :: Integer -> Literal
mkLitWord64Unchecked Integer
i = LitNumType -> Integer -> Literal
LitNumber LitNumType
LitNumWord64 Integer
i

-- | Creates a 'Literal' of type @Float#@
mkLitFloat :: Rational -> Literal
mkLitFloat :: Rational -> Literal
mkLitFloat = Rational -> Literal
LitFloat

-- | Creates a 'Literal' of type @Double#@
mkLitDouble :: Rational -> Literal
mkLitDouble :: Rational -> Literal
mkLitDouble = Rational -> Literal
LitDouble

-- | Creates a 'Literal' of type @Char#@
mkLitChar :: Char -> Literal
mkLitChar :: Char -> Literal
mkLitChar = Char -> Literal
LitChar

-- | 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@
mkLitString :: String -> Literal
-- stored UTF-8 encoded
mkLitString :: String -> Literal
mkLitString String
s = ByteString -> Literal
LitString (FastString -> ByteString
bytesFS (FastString -> ByteString) -> FastString -> ByteString
forall a b. (a -> b) -> a -> b
$ String -> FastString
mkFastString String
s)

mkLitInteger :: Integer -> Literal
mkLitInteger :: Integer -> Literal
mkLitInteger Integer
x = LitNumType -> Integer -> Literal
LitNumber LitNumType
LitNumInteger Integer
x

mkLitNatural :: Integer -> Literal
mkLitNatural :: Integer -> Literal
mkLitNatural Integer
x = ASSERT2( inNaturalRange x,  integer x )
                    (LitNumType -> Integer -> Literal
LitNumber LitNumType
LitNumNatural Integer
x)

inNaturalRange :: Integer -> Bool
inNaturalRange :: Integer -> Bool
inNaturalRange Integer
x = Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
>= Integer
0

inInt64Range, inWord64Range :: Integer -> Bool
inInt64Range :: Integer -> Bool
inInt64Range Integer
x  = Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
>= Int64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Int64
forall a. Bounded a => a
minBound :: Int64) Bool -> Bool -> Bool
&&
                  Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
<= Int64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Int64
forall a. Bounded a => a
maxBound :: Int64)
inWord64Range :: Integer -> Bool
inWord64Range Integer
x = Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
>= Word64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Word64
forall a. Bounded a => a
minBound :: Word64) Bool -> Bool -> Bool
&&
                  Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
<= Word64 -> Integer
forall a. Integral a => a -> Integer
toInteger (Word64
forall a. Bounded a => a
maxBound :: Word64)

inCharRange :: Char -> Bool
inCharRange :: Char -> Bool
inCharRange Char
c =  Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
>= Char
'\0' Bool -> Bool -> Bool
&& Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
<= Int -> Char
chr Int
tARGET_MAX_CHAR

-- | Tests whether the literal represents a zero of whatever type it is
isZeroLit :: Literal -> Bool
isZeroLit :: Literal -> Bool
isZeroLit (LitNumber LitNumType
_ Integer
0) = Bool
True
isZeroLit (LitFloat  Rational
0)   = Bool
True
isZeroLit (LitDouble Rational
0)   = Bool
True
isZeroLit Literal
_               = Bool
False

-- | Returns the 'Integer' contained in the 'Literal', for when that makes
-- sense, i.e. for 'Char', 'Int', 'Word', 'LitInteger' and 'LitNatural'.
litValue  :: Literal -> Integer
litValue :: Literal -> Integer
litValue Literal
l = case Literal -> Maybe Integer
isLitValue_maybe Literal
l of
   Just Integer
x  -> Integer
x
   Maybe Integer
Nothing -> String -> SDoc -> Integer
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"litValue" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

-- | Returns the 'Integer' contained in the 'Literal', for when that makes
-- sense, i.e. for 'Char' and numbers.
isLitValue_maybe  :: Literal -> Maybe Integer
isLitValue_maybe :: Literal -> Maybe Integer
isLitValue_maybe (LitChar   Char
c)     = Integer -> Maybe Integer
forall a. a -> Maybe a
Just (Integer -> Maybe Integer) -> Integer -> Maybe Integer
forall a b. (a -> b) -> a -> b
$ Int -> Integer
forall a. Integral a => a -> Integer
toInteger (Int -> Integer) -> Int -> Integer
forall a b. (a -> b) -> a -> b
$ Char -> Int
ord Char
c
isLitValue_maybe (LitNumber LitNumType
_ Integer
i)   = Integer -> Maybe Integer
forall a. a -> Maybe a
Just Integer
i
isLitValue_maybe Literal
_                 = Maybe Integer
forall a. Maybe a
Nothing

-- | Apply a function to the 'Integer' contained in the 'Literal', for when that
-- makes sense, e.g. for 'Char' and numbers.
-- For fixed-size integral literals, the result will be wrapped in accordance
-- with the semantics of the target type.
-- See Note [Word/Int underflow/overflow]
mapLitValue  :: Platform -> (Integer -> Integer) -> Literal -> Literal
mapLitValue :: Platform -> (Integer -> Integer) -> Literal -> Literal
mapLitValue Platform
_        Integer -> Integer
f (LitChar   Char
c)      = Char -> Literal
mkLitChar (Char -> Char
fchar Char
c)
   where fchar :: Char -> Char
fchar = Int -> Char
chr (Int -> Char) -> (Char -> Int) -> Char -> Char
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Integer -> Int
forall a. Num a => Integer -> a
fromInteger (Integer -> Int) -> (Char -> Integer) -> Char -> Int
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Integer -> Integer
f (Integer -> Integer) -> (Char -> Integer) -> Char -> Integer
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> Integer
forall a. Integral a => a -> Integer
toInteger (Int -> Integer) -> (Char -> Int) -> Char -> Integer
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Char -> Int
ord
mapLitValue Platform
platform Integer -> Integer
f (LitNumber LitNumType
nt Integer
i)   = Platform -> Literal -> Literal
wrapLitNumber Platform
platform (LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (Integer -> Integer
f Integer
i))
mapLitValue Platform
_        Integer -> Integer
_ Literal
l                  = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"mapLitValue" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

-- | Indicate if the `Literal` contains an 'Integer' value, e.g. 'Char',
-- 'Int', 'Word', 'LitInteger' and 'LitNatural'.
isLitValue  :: Literal -> Bool
isLitValue :: Literal -> Bool
isLitValue = Maybe Integer -> Bool
forall a. Maybe a -> Bool
isJust (Maybe Integer -> Bool)
-> (Literal -> Maybe Integer) -> Literal -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Literal -> Maybe Integer
isLitValue_maybe

{-
        Coercions
        ~~~~~~~~~
-}

narrow8IntLit, narrow16IntLit, narrow32IntLit,
  narrow8WordLit, narrow16WordLit, narrow32WordLit,
  char2IntLit, int2CharLit,
  float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit,
  float2DoubleLit, double2FloatLit
  :: Literal -> Literal

word2IntLit, int2WordLit :: Platform -> Literal -> Literal
word2IntLit :: Platform -> Literal -> Literal
word2IntLit Platform
platform (LitNumber LitNumType
LitNumWord Integer
w)
  -- Map Word range [max_int+1, max_word]
  -- to Int range   [min_int  , -1]
  -- Range [0,max_int] has the same representation with both Int and Word
  | Integer
w Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
> Platform -> Integer
platformMaxInt Platform
platform = Platform -> Integer -> Literal
mkLitInt Platform
platform (Integer
w Integer -> Integer -> Integer
forall a. Num a => a -> a -> a
- Platform -> Integer
platformMaxWord Platform
platform Integer -> Integer -> Integer
forall a. Num a => a -> a -> a
- Integer
1)
  | Bool
otherwise                   = Platform -> Integer -> Literal
mkLitInt Platform
platform Integer
w
word2IntLit Platform
_ Literal
l = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"word2IntLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

int2WordLit :: Platform -> Literal -> Literal
int2WordLit Platform
platform (LitNumber LitNumType
LitNumInt Integer
i)
  -- Map Int range [min_int  , -1]
  -- to Word range [max_int+1, max_word]
  -- Range [0,max_int] has the same representation with both Int and Word
  | Integer
i Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
< Integer
0     = Platform -> Integer -> Literal
mkLitWord Platform
platform (Integer
1 Integer -> Integer -> Integer
forall a. Num a => a -> a -> a
+ Platform -> Integer
platformMaxWord Platform
platform Integer -> Integer -> Integer
forall a. Num a => a -> a -> a
+ Integer
i)
  | Bool
otherwise = Platform -> Integer -> Literal
mkLitWord Platform
platform Integer
i
int2WordLit Platform
_ Literal
l = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"int2WordLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

-- | Narrow a literal number (unchecked result range)
narrowLit :: forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit :: forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit Proxy a
_ (LitNumber LitNumType
nt Integer
i) = LitNumType -> Integer -> Literal
LitNumber LitNumType
nt (a -> Integer
forall a. Integral a => a -> Integer
toInteger (Integer -> a
forall a. Num a => Integer -> a
fromInteger Integer
i :: a))
narrowLit Proxy a
_ Literal
l                = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"narrowLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

narrow8IntLit :: Literal -> Literal
narrow8IntLit   = Proxy Int8 -> Literal -> Literal
forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit (Proxy Int8
forall {k} (t :: k). Proxy t
Proxy :: Proxy Int8)
narrow16IntLit :: Literal -> Literal
narrow16IntLit  = Proxy Int16 -> Literal -> Literal
forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit (Proxy Int16
forall {k} (t :: k). Proxy t
Proxy :: Proxy Int16)
narrow32IntLit :: Literal -> Literal
narrow32IntLit  = Proxy Int32 -> Literal -> Literal
forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit (Proxy Int32
forall {k} (t :: k). Proxy t
Proxy :: Proxy Int32)
narrow8WordLit :: Literal -> Literal
narrow8WordLit  = Proxy Word8 -> Literal -> Literal
forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit (Proxy Word8
forall {k} (t :: k). Proxy t
Proxy :: Proxy Word8)
narrow16WordLit :: Literal -> Literal
narrow16WordLit = Proxy Word16 -> Literal -> Literal
forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit (Proxy Word16
forall {k} (t :: k). Proxy t
Proxy :: Proxy Word16)
narrow32WordLit :: Literal -> Literal
narrow32WordLit = Proxy Word32 -> Literal -> Literal
forall a. Integral a => Proxy a -> Literal -> Literal
narrowLit (Proxy Word32
forall {k} (t :: k). Proxy t
Proxy :: Proxy Word32)

char2IntLit :: Literal -> Literal
char2IntLit (LitChar Char
c)       = Integer -> Literal
mkLitIntUnchecked (Int -> Integer
forall a. Integral a => a -> Integer
toInteger (Char -> Int
ord Char
c))
char2IntLit Literal
l                 = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"char2IntLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)
int2CharLit :: Literal -> Literal
int2CharLit (LitNumber LitNumType
_ Integer
i)   = Char -> Literal
LitChar (Int -> Char
chr (Integer -> Int
forall a. Num a => Integer -> a
fromInteger Integer
i))
int2CharLit Literal
l                 = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"int2CharLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

float2IntLit :: Literal -> Literal
float2IntLit (LitFloat Rational
f)      = Integer -> Literal
mkLitIntUnchecked (Rational -> Integer
forall a b. (RealFrac a, Integral b) => a -> b
truncate Rational
f)
float2IntLit Literal
l                 = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"float2IntLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)
int2FloatLit :: Literal -> Literal
int2FloatLit (LitNumber LitNumType
_ Integer
i)   = Rational -> Literal
LitFloat (Integer -> Rational
forall a. Num a => Integer -> a
fromInteger Integer
i)
int2FloatLit Literal
l                 = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"int2FloatLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

double2IntLit :: Literal -> Literal
double2IntLit (LitDouble Rational
f)     = Integer -> Literal
mkLitIntUnchecked (Rational -> Integer
forall a b. (RealFrac a, Integral b) => a -> b
truncate Rational
f)
double2IntLit Literal
l                 = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"double2IntLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)
int2DoubleLit :: Literal -> Literal
int2DoubleLit (LitNumber LitNumType
_ Integer
i)   = Rational -> Literal
LitDouble (Integer -> Rational
forall a. Num a => Integer -> a
fromInteger Integer
i)
int2DoubleLit Literal
l                 = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"int2DoubleLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

float2DoubleLit :: Literal -> Literal
float2DoubleLit (LitFloat  Rational
f) = Rational -> Literal
LitDouble Rational
f
float2DoubleLit Literal
l             = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"float2DoubleLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)
double2FloatLit :: Literal -> Literal
double2FloatLit (LitDouble Rational
d) = Rational -> Literal
LitFloat  Rational
d
double2FloatLit Literal
l             = String -> SDoc -> Literal
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"double2FloatLit" (Literal -> SDoc
forall a. Outputable a => a -> SDoc
ppr Literal
l)

nullAddrLit :: Literal
nullAddrLit :: Literal
nullAddrLit = Literal
LitNullAddr

-- | A nonsense literal of type @forall (a :: 'TYPE' 'UnliftedRep'). a@.
rubbishLit :: Literal
rubbishLit :: Literal
rubbishLit = Literal
LitRubbish

{-
        Predicates
        ~~~~~~~~~~
-}

-- | True if there is absolutely no penalty to duplicating the literal.
-- False principally of strings.
--
-- "Why?", you say? I'm glad you asked. Well, for one duplicating strings would
-- blow up code sizes. Not only this, it's also unsafe.
--
-- Consider a program that wants to traverse a string. One way it might do this
-- is to first compute the Addr# pointing to the end of the string, and then,
-- starting from the beginning, bump a pointer using eqAddr# to determine the
-- end. For instance,
--
-- @
-- -- Given pointers to the start and end of a string, count how many zeros
-- -- the string contains.
-- countZeros :: Addr# -> Addr# -> -> Int
-- countZeros start end = go start 0
--   where
--     go off n
--       | off `addrEq#` end = n
--       | otherwise         = go (off `plusAddr#` 1) n'
--       where n' | isTrue# (indexInt8OffAddr# off 0# ==# 0#) = n + 1
--                | otherwise                                 = n
-- @
--
-- Consider what happens if we considered strings to be trivial (and therefore
-- duplicable) and emitted a call like @countZeros "hello"# ("hello"#
-- `plusAddr`# 5)@. The beginning and end pointers do not belong to the same
-- string, meaning that an iteration like the above would blow up terribly.
-- This is what happened in #12757.
--
-- Ultimately the solution here is to make primitive strings a bit more
-- structured, ensuring that the compiler can't inline in ways that will break
-- user code. One approach to this is described in #8472.
litIsTrivial :: Literal -> Bool
--      c.f. GHC.Core.Utils.exprIsTrivial
litIsTrivial :: Literal -> Bool
litIsTrivial (LitString ByteString
_)    = Bool
False
litIsTrivial (LitNumber LitNumType
nt Integer
_) = case LitNumType
nt of
  LitNumType
LitNumInteger -> Bool
False
  LitNumType
LitNumNatural -> Bool
False
  LitNumType
LitNumInt     -> Bool
True
  LitNumType
LitNumInt64   -> Bool
True
  LitNumType
LitNumWord    -> Bool
True
  LitNumType
LitNumWord64  -> Bool
True
litIsTrivial Literal
_                  = Bool
True

-- | True if code space does not go bad if we duplicate this literal
litIsDupable :: Platform -> Literal -> Bool
--      c.f. GHC.Core.Utils.exprIsDupable
litIsDupable :: Platform -> Literal -> Bool
litIsDupable Platform
platform Literal
x = case Literal
x of
   (LitNumber LitNumType
nt Integer
i) -> case LitNumType
nt of
      LitNumType
LitNumInteger -> Platform -> Integer -> Bool
platformInIntRange Platform
platform Integer
i
      LitNumType
LitNumNatural -> Platform -> Integer -> Bool
platformInWordRange Platform
platform Integer
i
      LitNumType
LitNumInt     -> Bool
True
      LitNumType
LitNumInt64   -> Bool
True
      LitNumType
LitNumWord    -> Bool
True
      LitNumType
LitNumWord64  -> Bool
True
   (LitString ByteString
_) -> Bool
False
   Literal
_             -> Bool
True

litFitsInChar :: Literal -> Bool
litFitsInChar :: Literal -> Bool
litFitsInChar (LitNumber LitNumType
_ Integer
i) = Integer
i Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
>= Int -> Integer
forall a. Integral a => a -> Integer
toInteger (Char -> Int
ord Char
forall a. Bounded a => a
minBound)
                              Bool -> Bool -> Bool
&& Integer
i Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
<= Int -> Integer
forall a. Integral a => a -> Integer
toInteger (Char -> Int
ord Char
forall a. Bounded a => a
maxBound)
litFitsInChar Literal
_               = Bool
False

litIsLifted :: Literal -> Bool
litIsLifted :: Literal -> Bool
litIsLifted (LitNumber LitNumType
nt Integer
_) = case LitNumType
nt of
  LitNumType
LitNumInteger -> Bool
True
  LitNumType
LitNumNatural -> Bool
True
  LitNumType
LitNumInt     -> Bool
False
  LitNumType
LitNumInt64   -> Bool
False
  LitNumType
LitNumWord    -> Bool
False
  LitNumType
LitNumWord64  -> Bool
False
litIsLifted Literal
_                  = Bool
False

{-
        Types
        ~~~~~
-}

-- | Find the Haskell 'Type' the literal occupies
literalType :: Literal -> Type
literalType :: Literal -> Type
literalType Literal
LitNullAddr       = Type
addrPrimTy
literalType (LitChar Char
_)       = Type
charPrimTy
literalType (LitString  ByteString
_)    = Type
addrPrimTy
literalType (LitFloat Rational
_)      = Type
floatPrimTy
literalType (LitDouble Rational
_)     = Type
doublePrimTy
literalType (LitLabel FastString
_ Maybe Int
_ FunctionOrData
_)  = Type
addrPrimTy
literalType (LitNumber LitNumType
lt Integer
_)  = case LitNumType
lt of
   LitNumType
LitNumInteger -> Type
integerTy
   LitNumType
LitNumNatural -> Type
naturalTy
   LitNumType
LitNumInt     -> Type
intPrimTy
   LitNumType
LitNumInt64   -> Type
int64PrimTy
   LitNumType
LitNumWord    -> Type
wordPrimTy
   LitNumType
LitNumWord64  -> Type
word64PrimTy
literalType (Literal
LitRubbish)      = TyCoVar -> ArgFlag -> Type -> Type
mkForAllTy TyCoVar
a ArgFlag
Inferred (TyCoVar -> Type
mkTyVarTy TyCoVar
a)
  where
    a :: TyCoVar
a = TyCoVar
alphaTyVarUnliftedRep

absentLiteralOf :: TyCon -> Maybe Literal
-- Return a literal of the appropriate primitive
-- TyCon, to use as a placeholder when it doesn't matter
-- Rubbish literals are handled in GHC.Core.Opt.WorkWrap.Utils, because
--  1. Looking at the TyCon is not enough, we need the actual type
--  2. This would need to return a type application to a literal
absentLiteralOf :: TyCon -> Maybe Literal
absentLiteralOf TyCon
tc = UniqFM TyCon Literal -> TyCon -> Maybe Literal
forall key elt. Uniquable key => UniqFM key elt -> key -> Maybe elt
lookupUFM UniqFM TyCon Literal
absent_lits TyCon
tc

absent_lits :: UniqFM TyCon Literal
absent_lits :: UniqFM TyCon Literal
absent_lits = [(Unique, Literal)] -> UniqFM TyCon Literal
forall elt key. [(Unique, elt)] -> UniqFM key elt
listToUFM_Directly
                        -- Explicitly construct the mape from the known
                        -- keys of these tyCons.
                        [ (Unique
addrPrimTyConKey,    Literal
LitNullAddr)
                        , (Unique
charPrimTyConKey,    Char -> Literal
LitChar Char
'x')
                        , (Unique
intPrimTyConKey,     Integer -> Literal
mkLitIntUnchecked Integer
0)
                        , (Unique
int64PrimTyConKey,   Integer -> Literal
mkLitInt64Unchecked Integer
0)
                        , (Unique
wordPrimTyConKey,    Integer -> Literal
mkLitWordUnchecked Integer
0)
                        , (Unique
word64PrimTyConKey,  Integer -> Literal
mkLitWord64Unchecked Integer
0)
                        , (Unique
floatPrimTyConKey,   Rational -> Literal
LitFloat Rational
0)
                        , (Unique
doublePrimTyConKey,  Rational -> Literal
LitDouble Rational
0)
                        ]

{-
        Comparison
        ~~~~~~~~~~
-}

cmpLit :: Literal -> Literal -> Ordering
cmpLit :: Literal -> Literal -> Ordering
cmpLit (LitChar      Char
a)     (LitChar       Char
b)     = Char
a Char -> Char -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` Char
b
cmpLit (LitString    ByteString
a)     (LitString     ByteString
b)     = ByteString
a ByteString -> ByteString -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` ByteString
b
cmpLit (Literal
LitNullAddr)        (Literal
LitNullAddr)         = Ordering
EQ
cmpLit (LitFloat     Rational
a)     (LitFloat      Rational
b)     = Rational
a Rational -> Rational -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` Rational
b
cmpLit (LitDouble    Rational
a)     (LitDouble     Rational
b)     = Rational
a Rational -> Rational -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` Rational
b
cmpLit (LitLabel     FastString
a Maybe Int
_ FunctionOrData
_) (LitLabel      FastString
b Maybe Int
_ FunctionOrData
_) = FastString
a FastString -> FastString -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` FastString
b
cmpLit (LitNumber LitNumType
nt1 Integer
a)    (LitNumber LitNumType
nt2  Integer
b)
  | LitNumType
nt1 LitNumType -> LitNumType -> Bool
forall a. Eq a => a -> a -> Bool
== LitNumType
nt2 = Integer
a   Integer -> Integer -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` Integer
b
  | Bool
otherwise  = LitNumType
nt1 LitNumType -> LitNumType -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` LitNumType
nt2
cmpLit (Literal
LitRubbish)         (Literal
LitRubbish)          = Ordering
EQ
cmpLit Literal
lit1 Literal
lit2
  | Literal -> Int
litTag Literal
lit1 Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
< Literal -> Int
litTag Literal
lit2 = Ordering
LT
  | Bool
otherwise                 = Ordering
GT

litTag :: Literal -> Int
litTag :: Literal -> Int
litTag (LitChar      Char
_)   = Int
1
litTag (LitString    ByteString
_)   = Int
2
litTag (Literal
LitNullAddr)      = Int
3
litTag (LitFloat     Rational
_)   = Int
4
litTag (LitDouble    Rational
_)   = Int
5
litTag (LitLabel FastString
_ Maybe Int
_ FunctionOrData
_)   = Int
6
litTag (LitNumber  {})    = Int
7
litTag (Literal
LitRubbish)       = Int
8

{-
        Printing
        ~~~~~~~~
* See Note [Printing of literals in Core]
-}

pprLiteral :: (SDoc -> SDoc) -> Literal -> SDoc
pprLiteral :: (SDoc -> SDoc) -> Literal -> SDoc
pprLiteral SDoc -> SDoc
_       (LitChar Char
c)     = Char -> SDoc
pprPrimChar Char
c
pprLiteral SDoc -> SDoc
_       (LitString ByteString
s)   = ByteString -> SDoc
pprHsBytes ByteString
s
pprLiteral SDoc -> SDoc
_       (Literal
LitNullAddr)   = String -> SDoc
text String
"__NULL"
pprLiteral SDoc -> SDoc
_       (LitFloat Rational
f)    = Float -> SDoc
float (Rational -> Float
forall a. RealFloat a => Rational -> a
fromRat Rational
f) SDoc -> SDoc -> SDoc
<> SDoc
primFloatSuffix
pprLiteral SDoc -> SDoc
_       (LitDouble Rational
d)   = Double -> SDoc
double (Rational -> Double
forall a. RealFloat a => Rational -> a
fromRat Rational
d) SDoc -> SDoc -> SDoc
<> SDoc
primDoubleSuffix
pprLiteral SDoc -> SDoc
add_par (LitNumber LitNumType
nt Integer
i)
   = case LitNumType
nt of
       LitNumType
LitNumInteger -> (SDoc -> SDoc) -> Integer -> SDoc
pprIntegerVal SDoc -> SDoc
add_par Integer
i
       LitNumType
LitNumNatural -> (SDoc -> SDoc) -> Integer -> SDoc
pprIntegerVal SDoc -> SDoc
add_par Integer
i
       LitNumType
LitNumInt     -> Integer -> SDoc
pprPrimInt Integer
i
       LitNumType
LitNumInt64   -> Integer -> SDoc
pprPrimInt64 Integer
i
       LitNumType
LitNumWord    -> Integer -> SDoc
pprPrimWord Integer
i
       LitNumType
LitNumWord64  -> Integer -> SDoc
pprPrimWord64 Integer
i
pprLiteral SDoc -> SDoc
add_par (LitLabel FastString
l Maybe Int
mb FunctionOrData
fod) =
    SDoc -> SDoc
add_par (String -> SDoc
text String
"__label" SDoc -> SDoc -> SDoc
<+> SDoc
b SDoc -> SDoc -> SDoc
<+> FunctionOrData -> SDoc
forall a. Outputable a => a -> SDoc
ppr FunctionOrData
fod)
    where b :: SDoc
b = case Maybe Int
mb of
              Maybe Int
Nothing -> FastString -> SDoc
pprHsString FastString
l
              Just Int
x  -> SDoc -> SDoc
doubleQuotes (String -> SDoc
text (FastString -> String
unpackFS FastString
l String -> String -> String
forall a. [a] -> [a] -> [a]
++ Char
'@'Char -> String -> String
forall a. a -> [a] -> [a]
:Int -> String
forall a. Show a => a -> String
show Int
x))
pprLiteral SDoc -> SDoc
_       (Literal
LitRubbish)     = String -> SDoc
text String
"__RUBBISH"

pprIntegerVal :: (SDoc -> SDoc) -> Integer -> SDoc
-- See Note [Printing of literals in Core].
pprIntegerVal :: (SDoc -> SDoc) -> Integer -> SDoc
pprIntegerVal SDoc -> SDoc
add_par Integer
i | Integer
i Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
< Integer
0     = SDoc -> SDoc
add_par (Integer -> SDoc
integer Integer
i)
                        | Bool
otherwise = Integer -> SDoc
integer Integer
i

{-
Note [Printing of literals in Core]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The function `add_par` is used to wrap parenthesis around negative integers
(`LitInteger`) and labels (`LitLabel`), 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)
-------         -------            ----------------------
LitChar         'a'#
LitString       "aaa"#
LitNullAddr     "__NULL"
LitInt          -1#
LitInt64        -1L#
LitWord          1##
LitWord64        1L##
LitFloat        -1.0#
LitDouble       -1.0##
LitInteger      -1                 (-1)
LitLabel        "__label" ...      ("__label" ...)
LitRubbish      "__RUBBISH"

Note [Rubbish literals]
~~~~~~~~~~~~~~~~~~~~~~~
During worker/wrapper after demand analysis, where an argument
is unused (absent) we do the following w/w split (supposing that
y is absent):

  f x y z = e
===>
  f x y z = $wf x z
  $wf x z = let y = <absent value>
            in e

Usually the binding for y is ultimately optimised away, and
even if not it should never be evaluated -- but that's the
way the w/w split starts off.

What is <absent value>?
* For lifted values <absent value> can be a call to 'error'.
* For primitive types like Int# or Word# we can use any random
  value of that type.
* But what about /unlifted/ but /boxed/ types like MutVar# or
  Array#?   We need a literal value of that type.

That is 'LitRubbish'.  Since we need a rubbish literal for
many boxed, unlifted types, we say that LitRubbish has type
  LitRubbish :: forall (a :: TYPE UnliftedRep). a

So we might see a w/w split like
  $wf x z = let y :: Array# Int = LitRubbish @(Array# Int)
            in e

Recall that (TYPE UnliftedRep) is the kind of boxed, unlifted
heap pointers.

Here are the moving parts:

* We define LitRubbish as a constructor in GHC.Types.Literal.Literal

* It is given its polymorphic type by Literal.literalType

* GHC.Core.Opt.WorkWrap.Utils.mk_absent_let introduces a LitRubbish for absent
  arguments of boxed, unlifted type.

* In CoreToSTG we convert (RubishLit @t) to just ().  STG is
  untyped, so it doesn't matter that it points to a lifted
  value. The important thing is that it is a heap pointer,
  which the garbage collector can follow if it encounters it.

  We considered maintaining LitRubbish in STG, and lowering
  it in the code generators, but it seems simpler to do it
  once and for all in CoreToSTG.

  In GHC.ByteCode.Asm we just lower it as a 0 literal, because
  it's all boxed and lifted to the host GC anyway.
-}