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,
44 getBuiltinUniques, mkBuiltinUnique,
45 mkPseudoUnique1, mkPseudoUnique2, mkPseudoUnique3
48 #include "HsVersions.h"
50 import BasicTypes ( Boxity(..) )
51 import FastString ( FastString, uniqueOfFS )
54 import PrelBase ( Char(..), chr, ord )
59 %************************************************************************
61 \subsection[Unique-type]{@Unique@ type and operations}
63 %************************************************************************
65 The @Chars@ are ``tag letters'' that identify the @UniqueSupply@.
66 Fast comparison is everything on @Uniques@:
69 data Unique = MkUnique Int#
73 u2i :: Unique -> FAST_INT
77 Now come the functions which construct uniques from their pieces, and vice versa.
78 The stuff about unique *supplies* is handled further down this module.
81 mkUnique :: Char -> Int -> Unique -- Builds a unique from pieces
82 unpkUnique :: Unique -> (Char, Int) -- The reverse
84 mkUniqueGrimily :: Int# -> Unique -- A trap-door for UniqSupply
86 getKey :: Unique -> Int# -- for Var
88 incrUnique :: Unique -> Unique
89 deriveUnique :: Unique -> Int -> Unique
90 newTagUnique :: Unique -> Char -> Unique
92 isTupleKey :: Unique -> Bool
97 mkUniqueGrimily x = MkUnique x
100 getKey (MkUnique x) = x
102 incrUnique (MkUnique i) = MkUnique (i +# 1#)
104 -- deriveUnique uses an 'X' tag so that it won't clash with
105 -- any of the uniques produced any other way
106 deriveUnique (MkUnique i) delta = mkUnique 'X' (I# i + delta)
108 -- newTagUnique changes the "domain" of a unique to a different char
109 newTagUnique u c = mkUnique c i where (_,i) = unpkUnique u
111 -- pop the Char in the top 8 bits of the Unique(Supply)
113 -- No 64-bit bugs here, as long as we have at least 32 bits. --JSM
119 mkUnique (C# c) (I# i)
120 = MkUnique (w2i (tag `or#` bits))
122 tag = i2w (ord# c) `shiftL#` i2w_s 24#
123 bits = i2w i `and#` (i2w 16777215#){-``0x00ffffff''-}
125 unpkUnique (MkUnique u)
127 tag = C# (chr# (w2i ((i2w u) `shiftr` (i2w_s 24#))))
128 i = I# (w2i ((i2w u) `and#` (i2w 16777215#){-``0x00ffffff''-}))
132 shiftr x y = shiftRL# x y
137 %************************************************************************
139 \subsection[Uniquable-class]{The @Uniquable@ class}
141 %************************************************************************
144 class Uniquable a where
145 getUnique :: a -> Unique
147 hasKey :: Uniquable a => a -> Unique -> Bool
148 x `hasKey` k = getUnique x == k
150 instance Uniquable FastString where
151 getUnique fs = mkUniqueGrimily (uniqueOfFS fs)
153 instance Uniquable Int where
154 getUnique (I# i#) = mkUniqueGrimily i#
158 %************************************************************************
160 \subsection[Unique-instances]{Instance declarations for @Unique@}
162 %************************************************************************
164 And the whole point (besides uniqueness) is fast equality. We don't
165 use `deriving' because we want {\em precise} control of ordering
166 (equality on @Uniques@ is v common).
169 eqUnique (MkUnique u1) (MkUnique u2) = u1 ==# u2
170 ltUnique (MkUnique u1) (MkUnique u2) = u1 <# u2
171 leUnique (MkUnique u1) (MkUnique u2) = u1 <=# u2
173 cmpUnique (MkUnique u1) (MkUnique u2)
174 = if u1 ==# u2 then EQ else if u1 <# u2 then LT else GT
176 instance Eq Unique where
177 a == b = eqUnique a b
178 a /= b = not (eqUnique a b)
180 instance Ord Unique where
182 a <= b = leUnique a b
183 a > b = not (leUnique a b)
184 a >= b = not (ltUnique a b)
185 compare a b = cmpUnique a b
188 instance Uniquable Unique where
192 We do sometimes make strings with @Uniques@ in them:
194 pprUnique, pprUnique10 :: Unique -> SDoc
197 = case unpkUnique uniq of
198 (tag, u) -> finish_ppr tag u (iToBase62 u)
200 pprUnique10 uniq -- in base-10, dudes
201 = case unpkUnique uniq of
202 (tag, u) -> finish_ppr tag u (int u)
204 finish_ppr 't' u pp_u | u < 26
205 = -- Special case to make v common tyvars, t1, t2, ...
206 -- come out as a, b, ... (shorter, easier to read)
207 char (chr (ord 'a' + u))
208 finish_ppr tag u pp_u = char tag <> pp_u
210 instance Outputable Unique where
213 instance Show Unique where
214 showsPrec p uniq = showsPrecSDoc p (pprUnique uniq)
217 %************************************************************************
219 \subsection[Utils-base62]{Base-62 numbers}
221 %************************************************************************
223 A character-stingy way to read/write numbers (notably Uniques).
224 The ``62-its'' are \tr{[0-9a-zA-Z]}. We don't handle negative Ints.
225 Code stolen from Lennart.
227 # define BYTE_ARRAY GlaExts.ByteArray
228 # define RUN_ST ST.runST
229 # define AND_THEN >>=
230 # define AND_THEN_ >>
231 # define RETURN return
233 iToBase62 :: Int -> SDoc
238 #if __GLASGOW_HASKELL__ < 405
239 bytes = case chars62 of { BYTE_ARRAY bounds_who_needs_'em bytes -> bytes }
241 bytes = case chars62 of { BYTE_ARRAY _ _ bytes -> bytes }
245 case (indexCharArray# bytes n#) of { c ->
248 case (quotRem n 62) of { (q, I# r#) ->
249 case (indexCharArray# bytes r#) of { c ->
250 (<>) (iToBase62 q) (char (C# c)) }}
252 -- keep this at top level! (bug on 94/10/24 WDP)
253 chars62 :: BYTE_ARRAY Int
256 newCharArray (0, 61) AND_THEN \ ch_array ->
257 fill_in ch_array 0 62 "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
259 unsafeFreezeByteArray ch_array
262 fill_in ch_array i lim str
266 = writeCharArray ch_array i (str !! i) AND_THEN_
267 fill_in ch_array (i+1) lim str
270 %************************************************************************
272 \subsection[Uniques-prelude]{@Uniques@ for wired-in Prelude things}
274 %************************************************************************
276 Allocation of unique supply characters:
277 v,t,u : for renumbering value-, type- and usage- vars.
278 other a-z: lower case chars for unique supplies (see Main.lhs)
280 C-E: pseudo uniques (used in native-code generator)
281 X: uniques derived by deriveUnique
282 _: unifiable tyvars (above)
283 0-9: prelude things below
286 mkAlphaTyVarUnique i = mkUnique '1' i
288 mkPreludeClassUnique i = mkUnique '2' i
289 mkPreludeTyConUnique i = mkUnique '3' i
290 mkTupleTyConUnique Boxed a = mkUnique '4' a
291 mkTupleTyConUnique Unboxed a = mkUnique '5' a
293 -- Data constructor keys occupy *two* slots. The first is used for the
294 -- data constructor itself and its wrapper function (the function that
295 -- evaluates arguments as necessary and calls the worker). The second is
296 -- used for the worker function (the function that builds the constructor
299 mkPreludeDataConUnique i = mkUnique '6' (2*i) -- Must be alphabetic
300 mkTupleDataConUnique Boxed a = mkUnique '7' (2*a) -- ditto (*may* be used in C labels)
301 mkTupleDataConUnique Unboxed a = mkUnique '8' (2*a)
303 -- This one is used for a tiresome reason
304 -- to improve a consistency-checking error check in the renamer
305 isTupleKey u = case unpkUnique u of
306 (tag,_) -> tag == '4' || tag == '5' || tag == '7' || tag == '8'
308 mkPrimOpIdUnique op = mkUnique '9' op
309 mkPreludeMiscIdUnique i = mkUnique '0' i
311 -- The "tyvar uniques" print specially nicely: a, b, c, etc.
312 -- See pprUnique for details
314 initTyVarUnique :: Unique
315 initTyVarUnique = mkUnique 't' 0
317 initTidyUniques :: (Unique, Unique) -- Global and local
318 initTidyUniques = (mkUnique 'g' 0, mkUnique 'x' 0)
320 mkPseudoUnique1, mkPseudoUnique2, mkPseudoUnique3,
321 mkBuiltinUnique :: Int -> Unique
323 mkBuiltinUnique i = mkUnique 'B' i
324 mkPseudoUnique1 i = mkUnique 'C' i -- used for getUnique on Regs
325 mkPseudoUnique2 i = mkUnique 'D' i -- used in NCG for getUnique on RealRegs
326 mkPseudoUnique3 i = mkUnique 'E' i -- used in NCG spiller to create spill VirtualRegs
330 getBuiltinUniques :: Int -> [Unique]
331 getBuiltinUniques n = map (mkUnique 'B') [1 .. n]