ghc /compiler/simplCore/CoreMonad.hs

Language Haskell Lines 907
MD5 Hash 236e131ddcb3bbcda1bb5c6a61882a63 Estimated Cost $14,229 (why?)
Repository git://github.com/ghc/ghc.git View Raw File View Project SPDX
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
{-
(c) The AQUA Project, Glasgow University, 1993-1998

\section[CoreMonad]{The core pipeline monad}
-}

{-# LANGUAGE CPP #-}

module CoreMonad (
    -- * Configuration of the core-to-core passes
    CoreToDo(..), runWhen, runMaybe,
    SimplifierMode(..),
    FloatOutSwitches(..),
    pprPassDetails,

    -- * Plugins
    PluginPass, bindsOnlyPass,

    -- * Counting
    SimplCount, doSimplTick, doFreeSimplTick, simplCountN,
    pprSimplCount, plusSimplCount, zeroSimplCount,
    isZeroSimplCount, hasDetailedCounts, Tick(..),

    -- * The monad
    CoreM, runCoreM,

    -- ** Reading from the monad
    getHscEnv, getRuleBase, getModule,
    getDynFlags, getOrigNameCache, getPackageFamInstEnv,
    getVisibleOrphanMods,
    getPrintUnqualified, getSrcSpanM,

    -- ** Writing to the monad
    addSimplCount,

    -- ** Lifting into the monad
    liftIO, liftIOWithCount,
    liftIO1, liftIO2, liftIO3, liftIO4,

    -- ** Global initialization
    reinitializeGlobals,

    -- ** Dealing with annotations
    getAnnotations, getFirstAnnotations,

    -- ** Screen output
    putMsg, putMsgS, errorMsg, errorMsgS, warnMsg,
    fatalErrorMsg, fatalErrorMsgS,
    debugTraceMsg, debugTraceMsgS,
    dumpIfSet_dyn,

#ifdef GHCI
    -- * Getting 'Name's
    thNameToGhcName
#endif
  ) where

#ifdef GHCI
import Name( Name )
import TcRnMonad        ( initTcForLookup )
#endif
import CoreSyn
import HscTypes
import Module
import DynFlags
import StaticFlags
import BasicTypes       ( CompilerPhase(..) )
import Annotations

import IOEnv hiding     ( liftIO, failM, failWithM )
import qualified IOEnv  ( liftIO )
import TcEnv            ( lookupGlobal )
import Var
import Outputable
import FastString
import qualified ErrUtils as Err
import ErrUtils( Severity(..) )
import Maybes
import UniqSupply
import UniqFM       ( UniqFM, mapUFM, filterUFM )
import MonadUtils
import SrcLoc
import ListSetOps       ( runs )
import Data.List
import Data.Ord
import Data.Dynamic
import Data.IORef
import Data.Map (Map)
import qualified Data.Map as Map
import Data.Word
import Control.Monad
import Control.Applicative ( Alternative(..) )

import Prelude hiding   ( read )

#ifdef GHCI
import Control.Concurrent.MVar (MVar)
import Linker ( PersistentLinkerState, saveLinkerGlobals, restoreLinkerGlobals )
import {-# SOURCE #-} TcSplice ( lookupThName_maybe )
import qualified Language.Haskell.TH as TH
#else
saveLinkerGlobals :: IO ()
saveLinkerGlobals = return ()

restoreLinkerGlobals :: () -> IO ()
restoreLinkerGlobals () = return ()
#endif

{-
************************************************************************
*                                                                      *
              The CoreToDo type and related types
          Abstraction of core-to-core passes to run.
*                                                                      *
************************************************************************
-}

data CoreToDo           -- These are diff core-to-core passes,
                        -- which may be invoked in any order,
                        -- as many times as you like.

  = CoreDoSimplify      -- The core-to-core simplifier.
        Int                    -- Max iterations
        SimplifierMode
  | CoreDoPluginPass String PluginPass
  | CoreDoFloatInwards
  | CoreDoFloatOutwards FloatOutSwitches
  | CoreLiberateCase
  | CoreDoPrintCore
  | CoreDoStaticArgs
  | CoreDoCallArity
  | CoreDoStrictness
  | CoreDoWorkerWrapper
  | CoreDoSpecialising
  | CoreDoSpecConstr
  | CoreCSE
  | CoreDoRuleCheck CompilerPhase String   -- Check for non-application of rules
                                           -- matching this string
  | CoreDoVectorisation
  | CoreDoNothing                -- Useful when building up
  | CoreDoPasses [CoreToDo]      -- lists of these things

  | CoreDesugar    -- Right after desugaring, no simple optimisation yet!
  | CoreDesugarOpt -- CoreDesugarXXX: Not strictly a core-to-core pass, but produces
                       --                 Core output, and hence useful to pass to endPass

  | CoreTidy
  | CorePrep

instance Outputable CoreToDo where
  ppr (CoreDoSimplify _ _)     = text "Simplifier"
  ppr (CoreDoPluginPass s _)   = text "Core plugin: " <+> text s
  ppr CoreDoFloatInwards       = text "Float inwards"
  ppr (CoreDoFloatOutwards f)  = text "Float out" <> parens (ppr f)
  ppr CoreLiberateCase         = text "Liberate case"
  ppr CoreDoStaticArgs         = text "Static argument"
  ppr CoreDoCallArity          = text "Called arity analysis"
  ppr CoreDoStrictness         = text "Demand analysis"
  ppr CoreDoWorkerWrapper      = text "Worker Wrapper binds"
  ppr CoreDoSpecialising       = text "Specialise"
  ppr CoreDoSpecConstr         = text "SpecConstr"
  ppr CoreCSE                  = text "Common sub-expression"
  ppr CoreDoVectorisation      = text "Vectorisation"
  ppr CoreDesugar              = text "Desugar (before optimization)"
  ppr CoreDesugarOpt           = text "Desugar (after optimization)"
  ppr CoreTidy                 = text "Tidy Core"
  ppr CorePrep                 = text "CorePrep"
  ppr CoreDoPrintCore          = text "Print core"
  ppr (CoreDoRuleCheck {})     = text "Rule check"
  ppr CoreDoNothing            = text "CoreDoNothing"
  ppr (CoreDoPasses passes)    = text "CoreDoPasses" <+> ppr passes

pprPassDetails :: CoreToDo -> SDoc
pprPassDetails (CoreDoSimplify n md) = vcat [ text "Max iterations =" <+> int n
                                            , ppr md ]
pprPassDetails _ = Outputable.empty

data SimplifierMode             -- See comments in SimplMonad
  = SimplMode
        { sm_names      :: [String] -- Name(s) of the phase
        , sm_phase      :: CompilerPhase
        , sm_rules      :: Bool     -- Whether RULES are enabled
        , sm_inline     :: Bool     -- Whether inlining is enabled
        , sm_case_case  :: Bool     -- Whether case-of-case is enabled
        , sm_eta_expand :: Bool     -- Whether eta-expansion is enabled
        }

instance Outputable SimplifierMode where
    ppr (SimplMode { sm_phase = p, sm_names = ss
                   , sm_rules = r, sm_inline = i
                   , sm_eta_expand = eta, sm_case_case = cc })
       = text "SimplMode" <+> braces (
         sep [ text "Phase =" <+> ppr p <+>
               brackets (text (concat $ intersperse "," ss)) <> comma
             , pp_flag i   (sLit "inline") <> comma
             , pp_flag r   (sLit "rules") <> comma
             , pp_flag eta (sLit "eta-expand") <> comma
             , pp_flag cc  (sLit "case-of-case") ])
         where
           pp_flag f s = ppUnless f (text "no") <+> ptext s

data FloatOutSwitches = FloatOutSwitches {
  floatOutLambdas   :: Maybe Int,  -- ^ Just n <=> float lambdas to top level, if
                                   -- doing so will abstract over n or fewer
                                   -- value variables
                                   -- Nothing <=> float all lambdas to top level,
                                   --             regardless of how many free variables
                                   -- Just 0 is the vanilla case: float a lambda
                                   --    iff it has no free vars

  floatOutConstants :: Bool,       -- ^ True <=> float constants to top level,
                                   --            even if they do not escape a lambda
  floatOutOverSatApps :: Bool,
                             -- ^ True <=> float out over-saturated applications
                             --            based on arity information.
                             -- See Note [Floating over-saturated applications]
                             -- in SetLevels
  floatToTopLevelOnly :: Bool      -- ^ Allow floating to the top level only.
  }
instance Outputable FloatOutSwitches where
    ppr = pprFloatOutSwitches

pprFloatOutSwitches :: FloatOutSwitches -> SDoc
pprFloatOutSwitches sw
  = text "FOS" <+> (braces $
     sep $ punctuate comma $
     [ text "Lam ="    <+> ppr (floatOutLambdas sw)
     , text "Consts =" <+> ppr (floatOutConstants sw)
     , text "OverSatApps ="   <+> ppr (floatOutOverSatApps sw) ])

-- The core-to-core pass ordering is derived from the DynFlags:
runWhen :: Bool -> CoreToDo -> CoreToDo
runWhen True  do_this = do_this
runWhen False _       = CoreDoNothing

runMaybe :: Maybe a -> (a -> CoreToDo) -> CoreToDo
runMaybe (Just x) f = f x
runMaybe Nothing  _ = CoreDoNothing

{-
Note [RULEs enabled in SimplGently]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
RULES are enabled when doing "gentle" simplification.  Two reasons:

  * We really want the class-op cancellation to happen:
        op (df d1 d2) --> $cop3 d1 d2
    because this breaks the mutual recursion between 'op' and 'df'

  * I wanted the RULE
        lift String ===> ...
    to work in Template Haskell when simplifying
    splices, so we get simpler code for literal strings

But watch out: list fusion can prevent floating.  So use phase control
to switch off those rules until after floating.


************************************************************************
*                                                                      *
             Types for Plugins
*                                                                      *
************************************************************************
-}

-- | A description of the plugin pass itself
type PluginPass = ModGuts -> CoreM ModGuts

bindsOnlyPass :: (CoreProgram -> CoreM CoreProgram) -> ModGuts -> CoreM ModGuts
bindsOnlyPass pass guts
  = do { binds' <- pass (mg_binds guts)
       ; return (guts { mg_binds = binds' }) }

{-
************************************************************************
*                                                                      *
             Counting and logging
*                                                                      *
************************************************************************
-}

verboseSimplStats :: Bool
verboseSimplStats = opt_PprStyle_Debug          -- For now, anyway

zeroSimplCount     :: DynFlags -> SimplCount
isZeroSimplCount   :: SimplCount -> Bool
hasDetailedCounts  :: SimplCount -> Bool
pprSimplCount      :: SimplCount -> SDoc
doSimplTick        :: DynFlags -> Tick -> SimplCount -> SimplCount
doFreeSimplTick    ::             Tick -> SimplCount -> SimplCount
plusSimplCount     :: SimplCount -> SimplCount -> SimplCount

data SimplCount
   = VerySimplCount !Int        -- Used when don't want detailed stats

   | SimplCount {
        ticks   :: !Int,        -- Total ticks
        details :: !TickCounts, -- How many of each type

        n_log   :: !Int,        -- N
        log1    :: [Tick],      -- Last N events; <= opt_HistorySize,
                                --   most recent first
        log2    :: [Tick]       -- Last opt_HistorySize events before that
                                -- Having log1, log2 lets us accumulate the
                                -- recent history reasonably efficiently
     }

type TickCounts = Map Tick Int

simplCountN :: SimplCount -> Int
simplCountN (VerySimplCount n)         = n
simplCountN (SimplCount { ticks = n }) = n

zeroSimplCount dflags
                -- This is where we decide whether to do
                -- the VerySimpl version or the full-stats version
  | dopt Opt_D_dump_simpl_stats dflags
  = SimplCount {ticks = 0, details = Map.empty,
                n_log = 0, log1 = [], log2 = []}
  | otherwise
  = VerySimplCount 0

isZeroSimplCount (VerySimplCount n)         = n==0
isZeroSimplCount (SimplCount { ticks = n }) = n==0

hasDetailedCounts (VerySimplCount {}) = False
hasDetailedCounts (SimplCount {})     = True

doFreeSimplTick tick sc@SimplCount { details = dts }
  = sc { details = dts `addTick` tick }
doFreeSimplTick _ sc = sc

doSimplTick dflags tick
    sc@(SimplCount { ticks = tks, details = dts, n_log = nl, log1 = l1 })
  | nl >= historySize dflags = sc1 { n_log = 1, log1 = [tick], log2 = l1 }
  | otherwise                = sc1 { n_log = nl+1, log1 = tick : l1 }
  where
    sc1 = sc { ticks = tks+1, details = dts `addTick` tick }

doSimplTick _ _ (VerySimplCount n) = VerySimplCount (n+1)


-- Don't use Map.unionWith because that's lazy, and we want to
-- be pretty strict here!
addTick :: TickCounts -> Tick -> TickCounts
addTick fm tick = case Map.lookup tick fm of
                        Nothing -> Map.insert tick 1 fm
                        Just n  -> n1 `seq` Map.insert tick n1 fm
                                where
                                   n1 = n+1


plusSimplCount sc1@(SimplCount { ticks = tks1, details = dts1 })
               sc2@(SimplCount { ticks = tks2, details = dts2 })
  = log_base { ticks = tks1 + tks2, details = Map.unionWith (+) dts1 dts2 }
  where
        -- A hackish way of getting recent log info
    log_base | null (log1 sc2) = sc1    -- Nothing at all in sc2
             | null (log2 sc2) = sc2 { log2 = log1 sc1 }
             | otherwise       = sc2

plusSimplCount (VerySimplCount n) (VerySimplCount m) = VerySimplCount (n+m)
plusSimplCount _                  _                  = panic "plusSimplCount"
       -- We use one or the other consistently

pprSimplCount (VerySimplCount n) = text "Total ticks:" <+> int n
pprSimplCount (SimplCount { ticks = tks, details = dts, log1 = l1, log2 = l2 })
  = vcat [text "Total ticks:    " <+> int tks,
          blankLine,
          pprTickCounts dts,
          if verboseSimplStats then
                vcat [blankLine,
                      text "Log (most recent first)",
                      nest 4 (vcat (map ppr l1) $$ vcat (map ppr l2))]
          else Outputable.empty
    ]

pprTickCounts :: Map Tick Int -> SDoc
pprTickCounts counts
  = vcat (map pprTickGroup groups)
  where
    groups :: [[(Tick,Int)]]    -- Each group shares a comon tag
                                -- toList returns common tags adjacent
    groups = runs same_tag (Map.toList counts)
    same_tag (tick1,_) (tick2,_) = tickToTag tick1 == tickToTag tick2

pprTickGroup :: [(Tick, Int)] -> SDoc
pprTickGroup group@((tick1,_):_)
  = hang (int (sum [n | (_,n) <- group]) <+> text (tickString tick1))
       2 (vcat [ int n <+> pprTickCts tick
                                    -- flip as we want largest first
               | (tick,n) <- sortBy (flip (comparing snd)) group])
pprTickGroup [] = panic "pprTickGroup"

data Tick
  = PreInlineUnconditionally    Id
  | PostInlineUnconditionally   Id

  | UnfoldingDone               Id
  | RuleFired                   FastString      -- Rule name

  | LetFloatFromLet
  | EtaExpansion                Id      -- LHS binder
  | EtaReduction                Id      -- Binder on outer lambda
  | BetaReduction               Id      -- Lambda binder


  | CaseOfCase                  Id      -- Bndr on *inner* case
  | KnownBranch                 Id      -- Case binder
  | CaseMerge                   Id      -- Binder on outer case
  | AltMerge                    Id      -- Case binder
  | CaseElim                    Id      -- Case binder
  | CaseIdentity                Id      -- Case binder
  | FillInCaseDefault           Id      -- Case binder

  | BottomFound
  | SimplifierDone              -- Ticked at each iteration of the simplifier

instance Outputable Tick where
  ppr tick = text (tickString tick) <+> pprTickCts tick

instance Eq Tick where
  a == b = case a `cmpTick` b of
           EQ -> True
           _ -> False

instance Ord Tick where
  compare = cmpTick

tickToTag :: Tick -> Int
tickToTag (PreInlineUnconditionally _)  = 0
tickToTag (PostInlineUnconditionally _) = 1
tickToTag (UnfoldingDone _)             = 2
tickToTag (RuleFired _)                 = 3
tickToTag LetFloatFromLet               = 4
tickToTag (EtaExpansion _)              = 5
tickToTag (EtaReduction _)              = 6
tickToTag (BetaReduction _)             = 7
tickToTag (CaseOfCase _)                = 8
tickToTag (KnownBranch _)               = 9
tickToTag (CaseMerge _)                 = 10
tickToTag (CaseElim _)                  = 11
tickToTag (CaseIdentity _)              = 12
tickToTag (FillInCaseDefault _)         = 13
tickToTag BottomFound                   = 14
tickToTag SimplifierDone                = 16
tickToTag (AltMerge _)                  = 17

tickString :: Tick -> String
tickString (PreInlineUnconditionally _) = "PreInlineUnconditionally"
tickString (PostInlineUnconditionally _)= "PostInlineUnconditionally"
tickString (UnfoldingDone _)            = "UnfoldingDone"
tickString (RuleFired _)                = "RuleFired"
tickString LetFloatFromLet              = "LetFloatFromLet"
tickString (EtaExpansion _)             = "EtaExpansion"
tickString (EtaReduction _)             = "EtaReduction"
tickString (BetaReduction _)            = "BetaReduction"
tickString (CaseOfCase _)               = "CaseOfCase"
tickString (KnownBranch _)              = "KnownBranch"
tickString (CaseMerge _)                = "CaseMerge"
tickString (AltMerge _)                 = "AltMerge"
tickString (CaseElim _)                 = "CaseElim"
tickString (CaseIdentity _)             = "CaseIdentity"
tickString (FillInCaseDefault _)        = "FillInCaseDefault"
tickString BottomFound                  = "BottomFound"
tickString SimplifierDone               = "SimplifierDone"

pprTickCts :: Tick -> SDoc
pprTickCts (PreInlineUnconditionally v) = ppr v
pprTickCts (PostInlineUnconditionally v)= ppr v
pprTickCts (UnfoldingDone v)            = ppr v
pprTickCts (RuleFired v)                = ppr v
pprTickCts LetFloatFromLet              = Outputable.empty
pprTickCts (EtaExpansion v)             = ppr v
pprTickCts (EtaReduction v)             = ppr v
pprTickCts (BetaReduction v)            = ppr v
pprTickCts (CaseOfCase v)               = ppr v
pprTickCts (KnownBranch v)              = ppr v
pprTickCts (CaseMerge v)                = ppr v
pprTickCts (AltMerge v)                 = ppr v
pprTickCts (CaseElim v)                 = ppr v
pprTickCts (CaseIdentity v)             = ppr v
pprTickCts (FillInCaseDefault v)        = ppr v
pprTickCts _                            = Outputable.empty

cmpTick :: Tick -> Tick -> Ordering
cmpTick a b = case (tickToTag a `compare` tickToTag b) of
                GT -> GT
                EQ -> cmpEqTick a b
                LT -> LT

cmpEqTick :: Tick -> Tick -> Ordering
cmpEqTick (PreInlineUnconditionally a)  (PreInlineUnconditionally b)    = a `compare` b
cmpEqTick (PostInlineUnconditionally a) (PostInlineUnconditionally b)   = a `compare` b
cmpEqTick (UnfoldingDone a)             (UnfoldingDone b)               = a `compare` b
cmpEqTick (RuleFired a)                 (RuleFired b)                   = a `compare` b
cmpEqTick (EtaExpansion a)              (EtaExpansion b)                = a `compare` b
cmpEqTick (EtaReduction a)              (EtaReduction b)                = a `compare` b
cmpEqTick (BetaReduction a)             (BetaReduction b)               = a `compare` b
cmpEqTick (CaseOfCase a)                (CaseOfCase b)                  = a `compare` b
cmpEqTick (KnownBranch a)               (KnownBranch b)                 = a `compare` b
cmpEqTick (CaseMerge a)                 (CaseMerge b)                   = a `compare` b
cmpEqTick (AltMerge a)                  (AltMerge b)                    = a `compare` b
cmpEqTick (CaseElim a)                  (CaseElim b)                    = a `compare` b
cmpEqTick (CaseIdentity a)              (CaseIdentity b)                = a `compare` b
cmpEqTick (FillInCaseDefault a)         (FillInCaseDefault b)           = a `compare` b
cmpEqTick _                             _                               = EQ

{-
************************************************************************
*                                                                      *
             Monad and carried data structure definitions
*                                                                      *
************************************************************************
-}

newtype CoreState = CoreState {
        cs_uniq_supply :: UniqSupply
}

data CoreReader = CoreReader {
        cr_hsc_env             :: HscEnv,
        cr_rule_base           :: RuleBase,
        cr_module              :: Module,
        cr_print_unqual        :: PrintUnqualified,
        cr_loc                 :: SrcSpan,   -- Use this for log/error messages so they
                                             -- are at least tagged with the right source file
        cr_visible_orphan_mods :: !ModuleSet,
#ifdef GHCI
        cr_globals :: (MVar PersistentLinkerState, Bool)
#else
        cr_globals :: ()
#endif
}

-- Note: CoreWriter used to be defined with data, rather than newtype.  If it
-- is defined that way again, the cw_simpl_count field, at least, must be
-- strict to avoid a space leak (Trac #7702).
newtype CoreWriter = CoreWriter {
        cw_simpl_count :: SimplCount
}

emptyWriter :: DynFlags -> CoreWriter
emptyWriter dflags = CoreWriter {
        cw_simpl_count = zeroSimplCount dflags
    }

plusWriter :: CoreWriter -> CoreWriter -> CoreWriter
plusWriter w1 w2 = CoreWriter {
        cw_simpl_count = (cw_simpl_count w1) `plusSimplCount` (cw_simpl_count w2)
    }

type CoreIOEnv = IOEnv CoreReader

-- | The monad used by Core-to-Core passes to access common state, register simplification
-- statistics and so on
newtype CoreM a = CoreM { unCoreM :: CoreState -> CoreIOEnv (a, CoreState, CoreWriter) }

instance Functor CoreM where
    fmap = liftM

instance Monad CoreM where
    mx >>= f = CoreM $ \s -> do
            (x, s', w1) <- unCoreM mx s
            (y, s'', w2) <- unCoreM (f x) s'
            let w = w1 `plusWriter` w2
            return $ seq w (y, s'', w)
            -- forcing w before building the tuple avoids a space leak
            -- (Trac #7702)

instance Applicative CoreM where
    pure x = CoreM $ \s -> nop s x
    (<*>) = ap
    m *> k = m >>= \_ -> k

instance Alternative CoreM where
    empty   = CoreM (const Control.Applicative.empty)
    m <|> n = CoreM (\rs -> unCoreM m rs <|> unCoreM n rs)

instance MonadPlus CoreM

instance MonadUnique CoreM where
    getUniqueSupplyM = do
        us <- getS cs_uniq_supply
        let (us1, us2) = splitUniqSupply us
        modifyS (\s -> s { cs_uniq_supply = us2 })
        return us1

    getUniqueM = do
        us <- getS cs_uniq_supply
        let (u,us') = takeUniqFromSupply us
        modifyS (\s -> s { cs_uniq_supply = us' })
        return u

runCoreM :: HscEnv
         -> RuleBase
         -> UniqSupply
         -> Module
         -> ModuleSet
         -> PrintUnqualified
         -> SrcSpan
         -> CoreM a
         -> IO (a, SimplCount)
runCoreM hsc_env rule_base us mod orph_imps print_unqual loc m
  = do { glbls <- saveLinkerGlobals
       ; liftM extract $ runIOEnv (reader glbls) $ unCoreM m state }
  where
    reader glbls = CoreReader {
            cr_hsc_env = hsc_env,
            cr_rule_base = rule_base,
            cr_module = mod,
            cr_visible_orphan_mods = orph_imps,
            cr_globals = glbls,
            cr_print_unqual = print_unqual,
            cr_loc = loc
        }
    state = CoreState {
            cs_uniq_supply = us
        }

    extract :: (a, CoreState, CoreWriter) -> (a, SimplCount)
    extract (value, _, writer) = (value, cw_simpl_count writer)

{-
************************************************************************
*                                                                      *
             Core combinators, not exported
*                                                                      *
************************************************************************
-}

nop :: CoreState -> a -> CoreIOEnv (a, CoreState, CoreWriter)
nop s x = do
    r <- getEnv
    return (x, s, emptyWriter $ (hsc_dflags . cr_hsc_env) r)

read :: (CoreReader -> a) -> CoreM a
read f = CoreM (\s -> getEnv >>= (\r -> nop s (f r)))

getS :: (CoreState -> a) -> CoreM a
getS f = CoreM (\s -> nop s (f s))

modifyS :: (CoreState -> CoreState) -> CoreM ()
modifyS f = CoreM (\s -> nop (f s) ())

write :: CoreWriter -> CoreM ()
write w = CoreM (\s -> return ((), s, w))

-- \subsection{Lifting IO into the monad}

-- | Lift an 'IOEnv' operation into 'CoreM'
liftIOEnv :: CoreIOEnv a -> CoreM a
liftIOEnv mx = CoreM (\s -> mx >>= (\x -> nop s x))

instance MonadIO CoreM where
    liftIO = liftIOEnv . IOEnv.liftIO

-- | Lift an 'IO' operation into 'CoreM' while consuming its 'SimplCount'
liftIOWithCount :: IO (SimplCount, a) -> CoreM a
liftIOWithCount what = liftIO what >>= (\(count, x) -> addSimplCount count >> return x)

{-
************************************************************************
*                                                                      *
             Reader, writer and state accessors
*                                                                      *
************************************************************************
-}

getHscEnv :: CoreM HscEnv
getHscEnv = read cr_hsc_env

getRuleBase :: CoreM RuleBase
getRuleBase = read cr_rule_base

getVisibleOrphanMods :: CoreM ModuleSet
getVisibleOrphanMods = read cr_visible_orphan_mods

getPrintUnqualified :: CoreM PrintUnqualified
getPrintUnqualified = read cr_print_unqual

getSrcSpanM :: CoreM SrcSpan
getSrcSpanM = read cr_loc

addSimplCount :: SimplCount -> CoreM ()
addSimplCount count = write (CoreWriter { cw_simpl_count = count })

-- Convenience accessors for useful fields of HscEnv

instance HasDynFlags CoreM where
    getDynFlags = fmap hsc_dflags getHscEnv

instance HasModule CoreM where
    getModule = read cr_module

-- | The original name cache is the current mapping from 'Module' and
-- 'OccName' to a compiler-wide unique 'Name'
getOrigNameCache :: CoreM OrigNameCache
getOrigNameCache = do
    nameCacheRef <- fmap hsc_NC getHscEnv
    liftIO $ fmap nsNames $ readIORef nameCacheRef

getPackageFamInstEnv :: CoreM PackageFamInstEnv
getPackageFamInstEnv = do
    hsc_env <- getHscEnv
    eps <- liftIO $ hscEPS hsc_env
    return $ eps_fam_inst_env eps

{-
************************************************************************
*                                                                      *
             Initializing globals
*                                                                      *
************************************************************************

This is a rather annoying function. When a plugin is loaded, it currently
gets linked against a *newly loaded* copy of the GHC package. This would
not be a problem, except that the new copy has its own mutable state
that is not shared with that state that has already been initialized by
the original GHC package.

(NB This mechanism is sufficient for granting plugins read-only access to
globals that are guaranteed to be initialized before the plugin is loaded.  If
any further synchronization is necessary, I would suggest using the more
sophisticated mechanism involving GHC.Conc.Sync.sharedCAF and rts/Globals.c to
share a single instance of the global variable among the compiler and the
plugins.  Perhaps we should migrate all global variables to use that mechanism,
for robustness... -- NSF July 2013)

This leads to loaded plugins calling GHC code which pokes the static flags,
and then dying with a panic because the static flags *it* sees are uninitialized.

There are two possible solutions:
  1. Export the symbols from the GHC executable from the GHC library and link
     against this existing copy rather than a new copy of the GHC library
  2. Carefully ensure that the global state in the two copies of the GHC
     library matches

I tried 1. and it *almost* works (and speeds up plugin load times!) except
on Windows. On Windows the GHC library tends to export more than 65536 symbols
(see #5292) which overflows the limit of what we can export from the EXE and
causes breakage.

(Note that if the GHC executable was dynamically linked this wouldn't be a
problem, because we could share the GHC library it links to.)

We are going to try 2. instead. Unfortunately, this means that every plugin
will have to say `reinitializeGlobals` before it does anything, but never mind.

I've threaded the cr_globals through CoreM rather than giving them as an
argument to the plugin function so that we can turn this function into
(return ()) without breaking any plugins when we eventually get 1. working.
-}

reinitializeGlobals :: CoreM ()
reinitializeGlobals = do
    linker_globals <- read cr_globals
    hsc_env <- getHscEnv
    let dflags = hsc_dflags hsc_env
    liftIO $ restoreLinkerGlobals linker_globals
    liftIO $ setUnsafeGlobalDynFlags dflags

{-
************************************************************************
*                                                                      *
             Dealing with annotations
*                                                                      *
************************************************************************
-}

-- | Get all annotations of a given type. This happens lazily, that is
-- no deserialization will take place until the [a] is actually demanded and
-- the [a] can also be empty (the UniqFM is not filtered).
--
-- This should be done once at the start of a Core-to-Core pass that uses
-- annotations.
--
-- See Note [Annotations]
getAnnotations :: Typeable a => ([Word8] -> a) -> ModGuts -> CoreM (UniqFM [a])
getAnnotations deserialize guts = do
     hsc_env <- getHscEnv
     ann_env <- liftIO $ prepareAnnotations hsc_env (Just guts)
     return (deserializeAnns deserialize ann_env)

-- | Get at most one annotation of a given type per Unique.
getFirstAnnotations :: Typeable a => ([Word8] -> a) -> ModGuts -> CoreM (UniqFM a)
getFirstAnnotations deserialize guts
  = liftM (mapUFM head . filterUFM (not . null))
  $ getAnnotations deserialize guts

{-
Note [Annotations]
~~~~~~~~~~~~~~~~~~
A Core-to-Core pass that wants to make use of annotations calls
getAnnotations or getFirstAnnotations at the beginning to obtain a UniqFM with
annotations of a specific type. This produces all annotations from interface
files read so far. However, annotations from interface files read during the
pass will not be visible until getAnnotations is called again. This is similar
to how rules work and probably isn't too bad.

The current implementation could be optimised a bit: when looking up
annotations for a thing from the HomePackageTable, we could search directly in
the module where the thing is defined rather than building one UniqFM which
contains all annotations we know of. This would work because annotations can
only be given to things defined in the same module. However, since we would
only want to deserialise every annotation once, we would have to build a cache
for every module in the HTP. In the end, it's probably not worth it as long as
we aren't using annotations heavily.

************************************************************************
*                                                                      *
                Direct screen output
*                                                                      *
************************************************************************
-}

msg :: Severity -> SDoc -> CoreM ()
msg sev doc
  = do { dflags <- getDynFlags
       ; loc    <- getSrcSpanM
       ; unqual <- getPrintUnqualified
       ; let sty = case sev of
                     SevError   -> err_sty
                     SevWarning -> err_sty
                     SevDump    -> dump_sty
                     _          -> user_sty
             err_sty  = mkErrStyle dflags unqual
             user_sty = mkUserStyle unqual AllTheWay
             dump_sty = mkDumpStyle unqual
       ; liftIO $
         (log_action dflags) dflags NoReason sev loc sty doc }

-- | Output a String message to the screen
putMsgS :: String -> CoreM ()
putMsgS = putMsg . text

-- | Output a message to the screen
putMsg :: SDoc -> CoreM ()
putMsg = msg SevInfo

-- | Output an error to the screen. Does not cause the compiler to die.
errorMsgS :: String -> CoreM ()
errorMsgS = errorMsg . text

-- | Output an error to the screen. Does not cause the compiler to die.
errorMsg :: SDoc -> CoreM ()
errorMsg = msg SevError

warnMsg :: SDoc -> CoreM ()
warnMsg = msg SevWarning

-- | Output a fatal error to the screen. Does not cause the compiler to die.
fatalErrorMsgS :: String -> CoreM ()
fatalErrorMsgS = fatalErrorMsg . text

-- | Output a fatal error to the screen. Does not cause the compiler to die.
fatalErrorMsg :: SDoc -> CoreM ()
fatalErrorMsg = msg SevFatal

-- | Output a string debugging message at verbosity level of @-v@ or higher
debugTraceMsgS :: String -> CoreM ()
debugTraceMsgS = debugTraceMsg . text

-- | Outputs a debugging message at verbosity level of @-v@ or higher
debugTraceMsg :: SDoc -> CoreM ()
debugTraceMsg = msg SevDump

-- | Show some labelled 'SDoc' if a particular flag is set or at a verbosity level of @-v -ddump-most@ or higher
dumpIfSet_dyn :: DumpFlag -> String -> SDoc -> CoreM ()
dumpIfSet_dyn flag str doc
  = do { dflags <- getDynFlags
       ; unqual <- getPrintUnqualified
       ; when (dopt flag dflags) $ liftIO $
         Err.dumpSDoc dflags unqual flag str doc }

{-
************************************************************************
*                                                                      *
               Finding TyThings
*                                                                      *
************************************************************************
-}

instance MonadThings CoreM where
    lookupThing name = do { hsc_env <- getHscEnv
                          ; liftIO $ lookupGlobal hsc_env name }

{-
************************************************************************
*                                                                      *
               Template Haskell interoperability
*                                                                      *
************************************************************************
-}

#ifdef GHCI
-- | Attempt to convert a Template Haskell name to one that GHC can
-- understand. Original TH names such as those you get when you use
-- the @'foo@ syntax will be translated to their equivalent GHC name
-- exactly. Qualified or unqualifed TH names will be dynamically bound
-- to names in the module being compiled, if possible. Exact TH names
-- will be bound to the name they represent, exactly.
thNameToGhcName :: TH.Name -> CoreM (Maybe Name)
thNameToGhcName th_name = do
    hsc_env <- getHscEnv
    liftIO $ initTcForLookup hsc_env (lookupThName_maybe th_name)
#endif
Back to Top