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 mkPseudoUnique1, mkPseudoUnique2, mkPseudoUnique3
48 #include "HsVersions.h"
50 import BasicTypes ( Boxity(..) )
51 import FastString ( FastString, uniqueOfFS )
54 import PrelBase ( Char(..), chr, ord )
60 %************************************************************************
62 \subsection[Unique-type]{@Unique@ type and operations}
64 %************************************************************************
66 The @Chars@ are ``tag letters'' that identify the @UniqueSupply@.
67 Fast comparison is everything on @Uniques@:
70 data Unique = MkUnique Int#
74 u2i :: Unique -> FastInt
78 Now come the functions which construct uniques from their pieces, and vice versa.
79 The stuff about unique *supplies* is handled further down this module.
82 mkUnique :: Char -> Int -> Unique -- Builds a unique from pieces
83 unpkUnique :: Unique -> (Char, Int) -- The reverse
85 mkUniqueGrimily :: Int# -> Unique -- A trap-door for UniqSupply
87 getKey :: Unique -> Int# -- for Var
89 incrUnique :: Unique -> Unique
90 deriveUnique :: Unique -> Int -> Unique
91 newTagUnique :: Unique -> Char -> Unique
93 isTupleKey :: Unique -> Bool
98 mkUniqueGrimily x = MkUnique x
100 {-# INLINE getKey #-}
101 getKey (MkUnique x) = x
103 incrUnique (MkUnique i) = MkUnique (i +# 1#)
105 -- deriveUnique uses an 'X' tag so that it won't clash with
106 -- any of the uniques produced any other way
107 deriveUnique (MkUnique i) delta = mkUnique 'X' (I# i + delta)
109 -- newTagUnique changes the "domain" of a unique to a different char
110 newTagUnique u c = mkUnique c i where (_,i) = unpkUnique u
112 -- pop the Char in the top 8 bits of the Unique(Supply)
114 -- No 64-bit bugs here, as long as we have at least 32 bits. --JSM
120 mkUnique (C# c) (I# i)
121 = MkUnique (w2i (tag `or#` bits))
123 #if __GLASGOW_HASKELL__ >= 503
124 tag = i2w (ord# c) `uncheckedShiftL#` i2w_s 24#
126 tag = i2w (ord# c) `shiftL#` i2w_s 24#
128 bits = i2w i `and#` (i2w 16777215#){-``0x00ffffff''-}
130 unpkUnique (MkUnique u)
132 tag = C# (chr# (w2i ((i2w u) `shiftr` (i2w_s 24#))))
133 i = I# (w2i ((i2w u) `and#` (i2w 16777215#){-``0x00ffffff''-}))
137 #if __GLASGOW_HASKELL__ >= 503
138 shiftr x y = uncheckedShiftRL# x y
140 shiftr x y = shiftRL# x y
146 %************************************************************************
148 \subsection[Uniquable-class]{The @Uniquable@ class}
150 %************************************************************************
153 class Uniquable a where
154 getUnique :: a -> Unique
156 hasKey :: Uniquable a => a -> Unique -> Bool
157 x `hasKey` k = getUnique x == k
159 instance Uniquable FastString where
160 getUnique fs = mkUniqueGrimily (uniqueOfFS fs)
162 instance Uniquable Int where
163 getUnique (I# i#) = mkUniqueGrimily i#
167 %************************************************************************
169 \subsection[Unique-instances]{Instance declarations for @Unique@}
171 %************************************************************************
173 And the whole point (besides uniqueness) is fast equality. We don't
174 use `deriving' because we want {\em precise} control of ordering
175 (equality on @Uniques@ is v common).
178 eqUnique (MkUnique u1) (MkUnique u2) = u1 ==# u2
179 ltUnique (MkUnique u1) (MkUnique u2) = u1 <# u2
180 leUnique (MkUnique u1) (MkUnique u2) = u1 <=# u2
182 cmpUnique (MkUnique u1) (MkUnique u2)
183 = if u1 ==# u2 then EQ else if u1 <# u2 then LT else GT
185 instance Eq Unique where
186 a == b = eqUnique a b
187 a /= b = not (eqUnique a b)
189 instance Ord Unique where
191 a <= b = leUnique a b
192 a > b = not (leUnique a b)
193 a >= b = not (ltUnique a b)
194 compare a b = cmpUnique a b
197 instance Uniquable Unique where
201 We do sometimes make strings with @Uniques@ in them:
203 pprUnique, pprUnique10 :: Unique -> SDoc
206 = case unpkUnique uniq of
207 (tag, u) -> finish_ppr tag u (iToBase62 u)
209 pprUnique10 uniq -- in base-10, dudes
210 = case unpkUnique uniq of
211 (tag, u) -> finish_ppr tag u (int u)
213 finish_ppr 't' u pp_u | u < 26
214 = -- Special case to make v common tyvars, t1, t2, ...
215 -- come out as a, b, ... (shorter, easier to read)
216 char (chr (ord 'a' + u))
217 finish_ppr tag u pp_u = char tag <> pp_u
219 instance Outputable Unique where
222 instance Show Unique where
223 showsPrec p uniq = showsPrecSDoc p (pprUnique uniq)
226 %************************************************************************
228 \subsection[Utils-base62]{Base-62 numbers}
230 %************************************************************************
232 A character-stingy way to read/write numbers (notably Uniques).
233 The ``62-its'' are \tr{[0-9a-zA-Z]}. We don't handle negative Ints.
234 Code stolen from Lennart.
236 # define BYTE_ARRAY GlaExts.ByteArray
237 # define RUN_ST ST.runST
238 # define AND_THEN >>=
239 # define AND_THEN_ >>
240 # define RETURN return
242 iToBase62 :: Int -> SDoc
247 #if __GLASGOW_HASKELL__ < 405
248 bytes = case chars62 of { BYTE_ARRAY bounds_who_needs_'em bytes -> bytes }
250 bytes = case chars62 of { BYTE_ARRAY _ _ bytes -> bytes }
254 case (indexCharArray# bytes n#) of { c ->
257 case (quotRem n 62) of { (q, I# r#) ->
258 case (indexCharArray# bytes r#) of { c ->
259 (<>) (iToBase62 q) (char (C# c)) }}
261 -- keep this at top level! (bug on 94/10/24 WDP)
262 chars62 :: BYTE_ARRAY Int
265 newCharArray (0, 61) AND_THEN \ ch_array ->
266 fill_in ch_array 0 62 "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
268 unsafeFreezeByteArray ch_array
271 fill_in ch_array i lim str
275 = writeCharArray ch_array i (str !! i) AND_THEN_
276 fill_in ch_array (i+1) lim str
279 %************************************************************************
281 \subsection[Uniques-prelude]{@Uniques@ for wired-in Prelude things}
283 %************************************************************************
285 Allocation of unique supply characters:
286 v,t,u : for renumbering value-, type- and usage- vars.
287 other a-z: lower case chars for unique supplies (see Main.lhs)
289 C-E: pseudo uniques (used in native-code generator)
290 X: uniques derived by deriveUnique
291 _: unifiable tyvars (above)
292 0-9: prelude things below
295 mkAlphaTyVarUnique i = mkUnique '1' i
297 mkPreludeClassUnique i = mkUnique '2' i
299 -- Prelude type constructors occupy *three* slots.
300 -- The first is for the tycon itself; the latter two
301 -- are for the generic to/from Ids. See TysWiredIn.mk_tc_gen_info.
303 mkPreludeTyConUnique i = mkUnique '3' (3*i)
304 mkTupleTyConUnique Boxed a = mkUnique '4' (3*a)
305 mkTupleTyConUnique Unboxed a = mkUnique '5' (3*a)
307 -- Data constructor keys occupy *two* slots. The first is used for the
308 -- data constructor itself and its wrapper function (the function that
309 -- evaluates arguments as necessary and calls the worker). The second is
310 -- used for the worker function (the function that builds the constructor
313 mkPreludeDataConUnique i = mkUnique '6' (2*i) -- Must be alphabetic
314 mkTupleDataConUnique Boxed a = mkUnique '7' (2*a) -- ditto (*may* be used in C labels)
315 mkTupleDataConUnique Unboxed a = mkUnique '8' (2*a)
317 -- This one is used for a tiresome reason
318 -- to improve a consistency-checking error check in the renamer
319 isTupleKey u = case unpkUnique u of
320 (tag,_) -> tag == '4' || tag == '5' || tag == '7' || tag == '8'
322 mkPrimOpIdUnique op = mkUnique '9' op
323 mkPreludeMiscIdUnique i = mkUnique '0' i
325 -- The "tyvar uniques" print specially nicely: a, b, c, etc.
326 -- See pprUnique for details
328 initTyVarUnique :: Unique
329 initTyVarUnique = mkUnique 't' 0
331 initTidyUniques :: (Unique, Unique) -- Global and local
332 initTidyUniques = (mkUnique 'g' 0, mkUnique 'x' 0)
334 mkPseudoUnique1, mkPseudoUnique2, mkPseudoUnique3,
335 mkBuiltinUnique :: Int -> Unique
337 mkBuiltinUnique i = mkUnique 'B' i
338 mkPseudoUnique1 i = mkUnique 'C' i -- used for getUnique on Regs
339 mkPseudoUnique2 i = mkUnique 'D' i -- used in NCG for getUnique on RealRegs
340 mkPseudoUnique3 i = mkUnique 'E' i -- used in NCG spiller to create spill VirtualRegs