2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 @Uniques@ are used to distinguish entities in the compiler (@Ids@,
6 @Classes@, etc.) from each other. Thus, @Uniques@ are the basic
7 comparison key in the compiler.
9 If there is any single operation that needs to be fast, it is @Unique@
10 comparison. Unsurprisingly, there is quite a bit of huff-and-puff
13 Some of the other hair in this code is to be able to use a
14 ``splittable @UniqueSupply@'' if requested/possible (not standard
19 Unique, Uniquable(..), hasKey,
20 u2i, -- hack: used in UniqFM
22 pprUnique, pprUnique10,
24 mkUnique, -- Used in UniqSupply
25 mkUniqueGrimily, -- Used in UniqSupply only!
26 getKey, -- Used in Var only!
28 incrUnique, -- Used for renumbering
29 deriveUnique, -- Ditto
30 newTagUnique, -- Used in CgCase
36 -- now all the built-in Uniques (and functions to make them)
37 -- [the Oh-So-Wonderful Haskell module system wins again...]
40 mkTupleTyConUnique, mkTupleDataConUnique,
41 mkPreludeMiscIdUnique, mkPreludeDataConUnique,
42 mkPreludeTyConUnique, mkPreludeClassUnique,
45 mkBuiltinUnique, builtinUniques,
46 mkPseudoUnique1, mkPseudoUnique2, mkPseudoUnique3
49 #include "HsVersions.h"
51 import BasicTypes ( Boxity(..) )
52 import FastString ( FastString, uniqueOfFS )
55 import Char ( chr, ord )
61 %************************************************************************
63 \subsection[Unique-type]{@Unique@ type and operations}
65 %************************************************************************
67 The @Chars@ are ``tag letters'' that identify the @UniqueSupply@.
68 Fast comparison is everything on @Uniques@:
71 data Unique = MkUnique Int#
75 u2i :: Unique -> FastInt
79 Now come the functions which construct uniques from their pieces, and vice versa.
80 The stuff about unique *supplies* is handled further down this module.
83 mkUnique :: Char -> Int -> Unique -- Builds a unique from pieces
84 unpkUnique :: Unique -> (Char, Int) -- The reverse
86 mkUniqueGrimily :: Int# -> Unique -- A trap-door for UniqSupply
88 getKey :: Unique -> Int# -- for Var
90 incrUnique :: Unique -> Unique
91 deriveUnique :: Unique -> Int -> Unique
92 newTagUnique :: Unique -> Char -> Unique
94 isTupleKey :: Unique -> Bool
99 mkUniqueGrimily x = MkUnique x
101 {-# INLINE getKey #-}
102 getKey (MkUnique x) = x
104 incrUnique (MkUnique i) = MkUnique (i +# 1#)
106 -- deriveUnique uses an 'X' tag so that it won't clash with
107 -- any of the uniques produced any other way
108 deriveUnique (MkUnique i) delta = mkUnique 'X' (I# i + delta)
110 -- newTagUnique changes the "domain" of a unique to a different char
111 newTagUnique u c = mkUnique c i where (_,i) = unpkUnique u
113 -- pop the Char in the top 8 bits of the Unique(Supply)
115 -- No 64-bit bugs here, as long as we have at least 32 bits. --JSM
121 mkUnique (C# c) (I# i)
122 = MkUnique (w2i (tag `or#` bits))
124 #if __GLASGOW_HASKELL__ >= 503
125 tag = i2w (ord# c) `uncheckedShiftL#` i2w_s 24#
127 tag = i2w (ord# c) `shiftL#` i2w_s 24#
129 bits = i2w i `and#` (i2w 16777215#){-``0x00ffffff''-}
131 unpkUnique (MkUnique u)
133 tag = C# (chr# (w2i ((i2w u) `shiftr` (i2w_s 24#))))
134 i = I# (w2i ((i2w u) `and#` (i2w 16777215#){-``0x00ffffff''-}))
138 #if __GLASGOW_HASKELL__ >= 503
139 shiftr x y = uncheckedShiftRL# x y
141 shiftr x y = shiftRL# x y
147 %************************************************************************
149 \subsection[Uniquable-class]{The @Uniquable@ class}
151 %************************************************************************
154 class Uniquable a where
155 getUnique :: a -> Unique
157 hasKey :: Uniquable a => a -> Unique -> Bool
158 x `hasKey` k = getUnique x == k
160 instance Uniquable FastString where
161 getUnique fs = mkUniqueGrimily (uniqueOfFS fs)
163 instance Uniquable Int where
164 getUnique (I# i#) = mkUniqueGrimily i#
168 %************************************************************************
170 \subsection[Unique-instances]{Instance declarations for @Unique@}
172 %************************************************************************
174 And the whole point (besides uniqueness) is fast equality. We don't
175 use `deriving' because we want {\em precise} control of ordering
176 (equality on @Uniques@ is v common).
179 eqUnique (MkUnique u1) (MkUnique u2) = u1 ==# u2
180 ltUnique (MkUnique u1) (MkUnique u2) = u1 <# u2
181 leUnique (MkUnique u1) (MkUnique u2) = u1 <=# u2
183 cmpUnique (MkUnique u1) (MkUnique u2)
184 = if u1 ==# u2 then EQ else if u1 <# u2 then LT else GT
186 instance Eq Unique where
187 a == b = eqUnique a b
188 a /= b = not (eqUnique a b)
190 instance Ord Unique where
192 a <= b = leUnique a b
193 a > b = not (leUnique a b)
194 a >= b = not (ltUnique a b)
195 compare a b = cmpUnique a b
198 instance Uniquable Unique where
202 We do sometimes make strings with @Uniques@ in them:
204 pprUnique, pprUnique10 :: Unique -> SDoc
207 = case unpkUnique uniq of
208 (tag, u) -> finish_ppr tag u (iToBase62 u)
210 pprUnique10 uniq -- in base-10, dudes
211 = case unpkUnique uniq of
212 (tag, u) -> finish_ppr tag u (int u)
214 finish_ppr 't' u pp_u | u < 26
215 = -- Special case to make v common tyvars, t1, t2, ...
216 -- come out as a, b, ... (shorter, easier to read)
217 char (chr (ord 'a' + u))
218 finish_ppr tag u pp_u = char tag <> pp_u
220 instance Outputable Unique where
223 instance Show Unique where
224 showsPrec p uniq = showsPrecSDoc p (pprUnique uniq)
227 %************************************************************************
229 \subsection[Utils-base62]{Base-62 numbers}
231 %************************************************************************
233 A character-stingy way to read/write numbers (notably Uniques).
234 The ``62-its'' are \tr{[0-9a-zA-Z]}. We don't handle negative Ints.
235 Code stolen from Lennart.
237 # define BYTE_ARRAY GlaExts.ByteArray
238 # define RUN_ST ST.runST
239 # define AND_THEN >>=
240 # define AND_THEN_ >>
241 # define RETURN return
243 iToBase62 :: Int -> SDoc
248 #if __GLASGOW_HASKELL__ < 405
249 bytes = case chars62 of { BYTE_ARRAY bounds_who_needs_'em bytes -> bytes }
251 bytes = case chars62 of { BYTE_ARRAY _ _ bytes -> bytes }
255 case (indexCharArray# bytes n#) of { c ->
258 case (quotRem n 62) of { (q, I# r#) ->
259 case (indexCharArray# bytes r#) of { c ->
260 (<>) (iToBase62 q) (char (C# c)) }}
262 -- keep this at top level! (bug on 94/10/24 WDP)
263 chars62 :: BYTE_ARRAY Int
266 newCharArray (0, 61) AND_THEN \ ch_array ->
267 fill_in ch_array 0 62 "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
269 unsafeFreezeByteArray ch_array
272 fill_in ch_array i lim str
276 = writeCharArray ch_array i (str !! i) AND_THEN_
277 fill_in ch_array (i+1) lim str
280 %************************************************************************
282 \subsection[Uniques-prelude]{@Uniques@ for wired-in Prelude things}
284 %************************************************************************
286 Allocation of unique supply characters:
287 v,t,u : for renumbering value-, type- and usage- vars.
288 other a-z: lower case chars for unique supplies (see Main.lhs)
290 C-E: pseudo uniques (used in native-code generator)
291 X: uniques derived by deriveUnique
292 _: unifiable tyvars (above)
293 0-9: prelude things below
296 mkAlphaTyVarUnique i = mkUnique '1' i
298 mkPreludeClassUnique i = mkUnique '2' i
300 -- Prelude type constructors occupy *three* slots.
301 -- The first is for the tycon itself; the latter two
302 -- are for the generic to/from Ids. See TysWiredIn.mk_tc_gen_info.
304 mkPreludeTyConUnique i = mkUnique '3' (3*i)
305 mkTupleTyConUnique Boxed a = mkUnique '4' (3*a)
306 mkTupleTyConUnique Unboxed a = mkUnique '5' (3*a)
308 -- Data constructor keys occupy *two* slots. The first is used for the
309 -- data constructor itself and its wrapper function (the function that
310 -- evaluates arguments as necessary and calls the worker). The second is
311 -- used for the worker function (the function that builds the constructor
314 mkPreludeDataConUnique i = mkUnique '6' (2*i) -- Must be alphabetic
315 mkTupleDataConUnique Boxed a = mkUnique '7' (2*a) -- ditto (*may* be used in C labels)
316 mkTupleDataConUnique Unboxed a = mkUnique '8' (2*a)
318 -- This one is used for a tiresome reason
319 -- to improve a consistency-checking error check in the renamer
320 isTupleKey u = case unpkUnique u of
321 (tag,_) -> tag == '4' || tag == '5' || tag == '7' || tag == '8'
323 mkPrimOpIdUnique op = mkUnique '9' op
324 mkPreludeMiscIdUnique i = mkUnique '0' i
326 -- No numbers left anymore, so I pick something different for the character
328 mkPArrDataConUnique a = mkUnique ':' (2*a)
330 -- The "tyvar uniques" print specially nicely: a, b, c, etc.
331 -- See pprUnique for details
333 initTyVarUnique :: Unique
334 initTyVarUnique = mkUnique 't' 0
336 initTidyUniques :: (Unique, Unique) -- Global and local
337 initTidyUniques = (mkUnique 'g' 0, mkUnique 'x' 0)
339 mkPseudoUnique1, mkPseudoUnique2, mkPseudoUnique3,
340 mkBuiltinUnique :: Int -> Unique
342 builtinUniques :: [Unique]
343 builtinUniques = map mkBuiltinUnique [1..]
345 mkBuiltinUnique i = mkUnique 'B' i
346 mkPseudoUnique1 i = mkUnique 'C' i -- used for getUnique on Regs
347 mkPseudoUnique2 i = mkUnique 'D' i -- used in NCG for getUnique on RealRegs
348 mkPseudoUnique3 i = mkUnique 'E' i -- used in NCG spiller to create spill VirtualRegs