More modules that need LANGUAGE BangPatterns

[ghc-hetmet.git] / compiler / basicTypes / Unique.lhs

diff --git a/compiler/basicTypes/Unique.lhs b/compiler/basicTypes/Unique.lhs
index 4028786..4180604 100644 (file)
--- a/compiler/basicTypes/Unique.lhs
+++ b/compiler/basicTypes/Unique.lhs
@@ -16,12 +16,16 @@ Some of the other hair in this code is to be able to use a
 Haskell).
 
 \begin{code}
+{-# LANGUAGE BangPatterns #-}
 module Unique (
-       Unique, Uniquable(..), hasKey,
+        -- * Main data types
+       Unique, Uniquable(..), 
+       
+       -- ** Constructors, desctructors and operations on 'Unique's
+       hasKey,
 
        pprUnique, 
 
-       mkUnique,                       -- Used in UniqSupply
        mkUniqueGrimily,                -- Used in UniqSupply only!
        getKey, getKeyFastInt,          -- Used in Var, UniqFM, Name only!
 
@@ -32,6 +36,8 @@ module Unique (
 
        isTupleKey, 
 
+        -- ** Making built-in uniques
+
        -- now all the built-in Uniques (and functions to make them)
        -- [the Oh-So-Wonderful Haskell module system wins again...]
        mkAlphaTyVarUnique,
@@ -41,6 +47,9 @@ module Unique (
        mkPreludeTyConUnique, mkPreludeClassUnique,
        mkPArrDataConUnique,
 
+        mkVarOccUnique, mkDataOccUnique, mkTvOccUnique, mkTcOccUnique,
+        mkRegSingleUnique, mkRegPairUnique, mkRegClassUnique, mkRegSubUnique,
+
        mkBuiltinUnique,
        mkPseudoUniqueC,
        mkPseudoUniqueD,
@@ -54,9 +63,7 @@ import BasicTypes
 import FastTypes
 import FastString
 import Outputable
-#ifdef DEBUG
-import StaticFlags     ( opt_SuppressUniques )
-#endif
+-- import StaticFlags
 
 #if defined(__GLASGOW_HASKELL__)
 --just for implementing a fast [0,61) -> Char function
@@ -78,6 +85,10 @@ Fast comparison is everything on @Uniques@:
 
 \begin{code}
 --why not newtype Int?
+
+-- | The type of unique identifiers that are used in many places in GHC
+-- for fast ordering and equality tests. You should generate these with
+-- the functions from the 'UniqSupply' module
 data Unique = MkUnique FastInt
 \end{code}
 
@@ -85,7 +96,6 @@ Now come the functions which construct uniques from their pieces, and vice versa
 The stuff about unique *supplies* is handled further down this module.
 
 \begin{code}
-mkUnique       :: Char -> Int -> Unique        -- Builds a unique from pieces
 unpkUnique     :: Unique -> (Char, Int)        -- The reverse
 
 mkUniqueGrimily :: Int -> Unique               -- A trap-door for UniqSupply
@@ -123,11 +133,14 @@ newTagUnique u c = mkUnique c i where (_,i) = unpkUnique u
 
 -- and as long as the Char fits in 8 bits, which we assume anyway!
 
+mkUnique :: Char -> Int -> Unique      -- Builds a unique from pieces
+-- NOT EXPORTED, so that we can see all the Chars that 
+--               are used in this one module
 mkUnique c i
   = MkUnique (tag `bitOrFastInt` bits)
   where
-    tag  = fastOrd (cUnbox c) `shiftLFastInt` _ILIT(24)
-    bits = iUnbox i `bitAndFastInt` _ILIT(16777215){-``0x00ffffff''-}
+    !tag  = fastOrd (cUnbox c) `shiftLFastInt` _ILIT(24)
+    !bits = iUnbox i `bitAndFastInt` _ILIT(16777215){-``0x00ffffff''-}
 
 unpkUnique (MkUnique u)
   = let
@@ -148,6 +161,7 @@ unpkUnique (MkUnique u)
 %************************************************************************
 
 \begin{code}
+-- | Class of things that we can obtain a 'Unique' from
 class Uniquable a where
     getUnique :: a -> Unique
 
@@ -202,11 +216,9 @@ We do sometimes make strings with @Uniques@ in them:
 \begin{code}
 pprUnique :: Unique -> SDoc
 pprUnique uniq
-#ifdef DEBUG
-  | opt_SuppressUniques
-  = empty      -- Used exclusively to suppress uniques so you 
-  | otherwise  -- can compare output easily
-#endif
+--   | opt_SuppressUniques
+--  = empty    -- Used exclusively to suppress uniques so you 
+--  | otherwise        -- can compare output easily
   = case unpkUnique uniq of
       (tag, u) -> finish_ppr tag u (text (iToBase62 u))
 
@@ -259,7 +271,7 @@ iToBase62 n_
 #if defined(__GLASGOW_HASKELL__)
     --then FastInt == Int#
     chooseChar62 n = C# (indexCharOffAddr# chars62 n)
-    chars62 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"#
+    !chars62 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"#
 #else
     --Haskell98 arrays are portable
     chooseChar62 n = (!) chars62 n
@@ -280,13 +292,14 @@ Allocation of unique supply characters:
        X:   uniques derived by deriveUnique
        _:   unifiable tyvars   (above)
        0-9: prelude things below
+            (no numbers left any more..)
+       ::   (prelude) parallel array data constructors
 
        other a-z: lower case chars for unique supplies.  Used so far:
 
        d       desugarer
        f       AbsC flattener
        g       SimplStg
-       l       ndpFlatten
        n       Native codegen
        r       Hsc name cache
        s       simplifier
@@ -329,11 +342,10 @@ mkTupleDataConUnique Unboxed a    = mkUnique '8' (2*a)
 isTupleKey u = case unpkUnique u of
                (tag,_) -> tag == '4' || tag == '5' || tag == '7' || tag == '8'
 
-mkPrimOpIdUnique op            = mkUnique '9' op
-mkPreludeMiscIdUnique i                = mkUnique '0' i
+mkPrimOpIdUnique op         = mkUnique '9' op
+mkPreludeMiscIdUnique  i    = mkUnique '0' i
 
--- No numbers left anymore, so I pick something different for the character
--- tag 
+-- No numbers left anymore, so I pick something different for the character tag 
 mkPArrDataConUnique a          = mkUnique ':' (2*a)
 
 -- The "tyvar uniques" print specially nicely: a, b, c, etc.
@@ -350,5 +362,18 @@ mkPseudoUniqueC i = mkUnique 'C' i -- used for getUnique on Regs
 mkPseudoUniqueD i = mkUnique 'D' i -- used in NCG for getUnique on RealRegs
 mkPseudoUniqueE i = mkUnique 'E' i -- used in NCG spiller to create spill VirtualRegs
 mkPseudoUniqueH i = mkUnique 'H' i -- used in NCG spiller to create spill VirtualRegs
+
+mkRegSingleUnique, mkRegPairUnique, mkRegSubUnique, mkRegClassUnique :: Int -> Unique
+mkRegSingleUnique = mkUnique 'R'
+mkRegSubUnique    = mkUnique 'S'
+mkRegPairUnique   = mkUnique 'P'
+mkRegClassUnique  = mkUnique 'L'
+
+mkVarOccUnique, mkDataOccUnique, mkTvOccUnique, mkTcOccUnique :: FastString -> Unique
+-- See Note [The Unique of an OccName] in OccName
+mkVarOccUnique  fs = mkUnique 'i' (iBox (uniqueOfFS fs))
+mkDataOccUnique fs = mkUnique 'd' (iBox (uniqueOfFS fs))
+mkTvOccUnique  fs = mkUnique 'v' (iBox (uniqueOfFS fs))
+mkTcOccUnique  fs = mkUnique 'c' (iBox (uniqueOfFS fs))
 \end{code}