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
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
|
%% -*- erlang-indent-level: 2 -*-
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2001-2013. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Copyright (c) 2001 by Erik Johansson. All Rights Reserved
%% ====================================================================
%% Filename : hipe_rtl_mk_switch.erl
%% Module : hipe_rtl_mk_switch
%% Purpose : Implements switching on Erlang values.
%% Notes : Only fixnums are supported well,
%% atoms work with table search,
%% the inline search of atoms might have some bugs.
%% Should be extended to handle bignums and floats.
%%
%% History : * 2001-02-28 Erik Johansson (happi@it.uu.se):
%% Created.
%% * 2001-04-01 Erik Trulsson (ertr1013@csd.uu.se):
%% Stefan Lindström (stli3993@csd.uu.se):
%% Added clustering and inlined binary search trees.
%% * 2001-07-30 EJ (happi@it.uu.se):
%% Fixed some bugs and started cleanup.
%% ====================================================================
%% Exports :
%% gen_switch_val(I, VarMap, ConstTab, Options)
%% gen_switch_tuple(I, Map, ConstTab, Options)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-module(hipe_rtl_mk_switch).
-export([gen_switch_val/4, gen_switch_tuple/4]).
%%-------------------------------------------------------------------------
-include("../main/hipe.hrl").
%%-------------------------------------------------------------------------
-define(MINFORJUMPTABLE,9).
% Minimum number of integers needed to use something else than an inline search.
-define(MINFORINTSEARCHTREE,65). % Must be at least 3
% Minimum number of integer elements needed to use a non-inline binary search.
-define(MININLINEATOMSEARCH,8).
% Minimum number of atoms needed to use an inline binary search instead
% of a fast linear search.
-define(MINFORATOMSEARCHTREE,20). % Must be at least 3
% Minimum number of atoms needed to use a non-inline binary search instead
% of a linear search.
-define(MAXINLINEATOMSEARCH,64). % Must be at least 3
% The cutoff point between inlined and non-inlined binary search for atoms
-define(WORDSIZE, hipe_rtl_arch:word_size()).
-define(MINDENSITY, 0.5).
% Minimum density required to use a jumptable instead of a binary search.
%% The reason why MINFORINTSEARCHTREE and MINFORATOMSEARCHTREE must be
%% at least 3 is that the function tab/5 will enter an infinite loop
%% and hang when faced with a switch of size 1 or 2.
%% Options used by this module:
%%
%% [no_]use_indexing
%% Determines if any indexing be should be done at all. Turned on
%% by default at optimization level o2 and higher.
%%
%% [no_]use_clusters
%% Controls whether we attempt to divide sparse integer switches
%% into smaller dense clusters for which jumptables are practical.
%% Turned off by default since it can increase compilation time
%% considerably and most programs will gain little benefit from it.
%%
%% [no_]use_inline_atom_search
%% Controls whether we use an inline binary search for small number
%% of atoms. Turned off by default since this is currently only
%% supported on SPARC (and not on x86) and probably needs a bit
%% more testing before it can be turned on by default.
gen_switch_val(I, VarMap, ConstTab, Options) ->
case proplists:get_bool(use_indexing, Options) of
false -> gen_slow_switch_val(I, VarMap, ConstTab, Options);
true -> gen_fast_switch_val(I, VarMap, ConstTab, Options)
end.
gen_fast_switch_val(I, VarMap, ConstTab, Options) ->
{Arg, VarMap0} =
hipe_rtl_varmap:icode_var2rtl_var(hipe_icode:switch_val_term(I), VarMap),
IcodeFail = hipe_icode:switch_val_fail_label(I),
{Fail, VarMap1} = hipe_rtl_varmap:icode_label2rtl_label(IcodeFail, VarMap0),
%% Important that the list of cases is sorted when handling integers.
UnsortedCases = hipe_icode:switch_val_cases(I),
Cases = lists:sort(UnsortedCases),
check_duplicates(Cases),
%% This check is currently not really necessary. The checking
%% happens at an earlier phase of the compilation.
{Types, InitCode} = split_types(Cases, Arg),
handle_types(Types, InitCode, VarMap1, ConstTab, Arg, {I, Fail, Options}).
handle_types([{Type,Lbl,Cases}|Types], Code, VarMap, ConstTab, Arg, Info) ->
{Code1,VarMap1,ConstTab1} = gen_fast_switch_on(Type, Cases,
VarMap,
ConstTab, Arg, Info),
handle_types(Types, [Code,Lbl,Code1], VarMap1, ConstTab1, Arg, Info);
handle_types([], Code, VarMap, ConstTab, _, _) ->
{Code, VarMap, ConstTab}.
gen_fast_switch_on(integer, Cases, VarMap, ConstTab, Arg, {I, Fail, Options}) ->
{First,_} = hd(Cases),
Min = hipe_icode:const_value(First),
if length(Cases) < ?MINFORJUMPTABLE ->
gen_small_switch_val(Arg,Cases,Fail,VarMap,ConstTab,Options);
true ->
case proplists:get_bool(use_clusters, Options) of
false ->
M = list_to_tuple(Cases),
D = density(M, 1, tuple_size(M)),
if
D >= ?MINDENSITY ->
gen_jump_table(Arg,Fail,hipe_icode:switch_val_fail_label(I),VarMap,ConstTab,Cases,Min);
true ->
gen_search_switch_val(Arg, Cases, Fail, VarMap, ConstTab, Options)
end;
true ->
MC = minclusters(Cases),
Cl = cluster_split(Cases,MC),
CM = cluster_merge(Cl),
find_cluster(CM,VarMap,ConstTab,Options,Arg,Fail,hipe_icode:switch_val_fail_label(I))
end
end;
gen_fast_switch_on(atom, Cases, VarMap, ConstTab, Arg, {_I, Fail, Options}) ->
case proplists:get_bool(use_inline_atom_search, Options) of
true ->
if
length(Cases) < ?MININLINEATOMSEARCH ->
gen_linear_switch_val(Arg, Cases, Fail, VarMap, ConstTab, Options);
length(Cases) > ?MAXINLINEATOMSEARCH ->
gen_search_switch_val(Arg, Cases, Fail, VarMap, ConstTab, Options);
true ->
gen_atom_switch_val(Arg,Cases,Fail,VarMap,ConstTab,Options)
end;
false ->
if length(Cases) < ?MINFORATOMSEARCHTREE ->
gen_linear_switch_val(Arg, Cases, Fail, VarMap, ConstTab, Options);
true ->
gen_search_switch_val(Arg, Cases, Fail, VarMap, ConstTab, Options)
end
end;
gen_fast_switch_on(_, _, VarMap, ConstTab, _, {I,_Fail,Options}) ->
%% We can only handle smart indexing of integers and atoms
%% TODO: Consider bignum
gen_slow_switch_val(I, VarMap, ConstTab, Options).
%% Split different types into separate switches.
split_types([Case|Cases], Arg) ->
Type1 = casetype(Case),
Types = split(Cases,Type1,[Case],[]),
switch_on_types(Types,[], [], Arg);
split_types([],_) ->
%% Cant happen.
?EXIT({empty_caselist}).
switch_on_types([{Type,Cases}], AccCode, AccCases, _Arg) ->
Lbl = hipe_rtl:mk_new_label(),
I = hipe_rtl:mk_goto(hipe_rtl:label_name(Lbl)),
{[{Type,Lbl,lists:reverse(Cases)} | AccCases], lists:reverse([I|AccCode])};
switch_on_types([{other,Cases} | Rest], AccCode, AccCases, Arg) ->
%% Make sure the general case is handled last.
switch_on_types(Rest ++ [{other,Cases}], AccCode, AccCases, Arg);
switch_on_types([{Type,Cases} | Rest], AccCode, AccCases, Arg) ->
TLab = hipe_rtl:mk_new_label(),
FLab = hipe_rtl:mk_new_label(),
TestCode =
case Type of
integer ->
hipe_tagscheme:test_fixnum(Arg, hipe_rtl:label_name(TLab),
hipe_rtl:label_name(FLab), 0.5);
atom ->
hipe_tagscheme:test_atom(Arg, hipe_rtl:label_name(TLab),
hipe_rtl:label_name(FLab), 0.5);
bignum ->
hipe_tagscheme:test_bignum(Arg, hipe_rtl:label_name(TLab),
hipe_rtl:label_name(FLab), 0.5);
_ -> ?EXIT({ooops, type_not_handled, Type})
end,
switch_on_types(Rest, [[TestCode,FLab] | AccCode],
[{Type,TLab,lists:reverse(Cases)} | AccCases], Arg).
split([Case|Cases], Type, Current, Rest) ->
case casetype(Case) of
Type ->
split(Cases, Type, [Case|Current],Rest);
Other ->
split(Cases, Other, [Case], [{Type,Current}|Rest])
end;
split([], Type, Current, Rest) ->
[{Type, Current} | Rest].
%% Determine what type an entry in the caselist has
casetype({Const,_}) ->
casetype(hipe_icode:const_value(Const));
casetype(A) ->
if
is_integer(A) ->
case hipe_tagscheme:is_fixnum(A) of
true -> integer;
false -> bignum
end;
is_float(A) -> float;
is_atom(A) -> atom;
true -> other
end.
%% check that no duplicate values occur in the case list and also
%% check that all case values have the same type.
check_duplicates([]) -> true;
check_duplicates([_]) -> true;
check_duplicates([{Const1,_},{Const2,L2}|T]) ->
C1 = hipe_icode:const_value(Const1),
C2 = hipe_icode:const_value(Const2),
%% T1 = casetype(C1),
%% T2 = casetype(C2),
if C1 =/= C2 -> %% , T1 =:= T2 ->
check_duplicates([{Const2,L2}|T]);
true ->
?EXIT({bad_values_in_switchval,C1})
end.
%%
%% Determine the optimal way to divide Cases into clusters such that each
%% cluster is dense.
%%
%% See:
%% Producing Good Code for the Case Statement, Robert L. Bernstein
%% Software - Practice and Experience vol 15, 1985, no 10, pp 1021--1024
%% And
%% Correction to "Producing Good Code for the Case Statement"
%% Sampath Kannan and Todd A. Proebsting,
%% Software - Practice and Experience vol 24, 1994, no 2, p 233
%%
%% (The latter is where the algorithm comes from.)
%% This function will return a tuple with the first element being 0
%% The rest of the elements being integers. A value of M at index N
%% (where the first element is considered to have index 0) means that
%% the first N cases can be divided into M (but no fewer) clusters where
%% each cluster is dense.
minclusters(Cases) when is_list(Cases) ->
minclusters(list_to_tuple(Cases));
minclusters(Cases) when is_tuple(Cases) ->
N = tuple_size(Cases),
MinClusters = list_to_tuple([0|n_list(N,inf)]),
i_loop(1,N,MinClusters,Cases).
%% Create a list with N elements initialized to Init
n_list(0,_) -> [];
n_list(N,Init) -> [Init | n_list(N-1,Init)].
%% Do the dirty work of minclusters
i_loop(I,N,MinClusters,_Cases) when I > N ->
MinClusters;
i_loop(I,N,MinClusters,Cases) when I =< N ->
M = j_loop(0, I-1, MinClusters, Cases),
i_loop(I+1, N, M, Cases).
%% More dirty work
j_loop(J,I1,MinClusters,_Cases) when J > I1 ->
MinClusters;
j_loop(J,I1,MinClusters,Cases) when J =< I1 ->
D = density(Cases,J+1,I1+1),
A0 = element(J+1,MinClusters),
A = if
is_number(A0) ->
A0+1;
true ->
A0
end,
B = element(I1+2,MinClusters),
M = if
D >= ?MINDENSITY, A<B ->
setelement(I1+2,MinClusters,A);
true ->
MinClusters
end,
j_loop(J+1,I1,M,Cases).
%% Determine the density of a (subset of a) case list
%% A is a tuple with the cases in order from smallest to largest
%% I is the index of the first element and J of the last
density(A,I,J) ->
{AI,_} = element(I,A),
{AJ,_} = element(J,A),
(J-I+1)/(hipe_icode:const_value(AJ)-hipe_icode:const_value(AI)+1).
%% Split a case list into dense clusters
%% Returns a list of lists of cases.
%%
%% Cases is the case list and Clust is a list describing the optimal
%% clustering as returned by minclusters
%%
%% If the value in the last place in minclusters is M then we can
%% split the case list into M clusters. We then search for the last
%% (== right-most) occurance of the value M-1 in minclusters. That
%% indicates the largest number of cases that can be split into M-1
%% clusters. This means that the cases in between constitute one
%% cluster. Then we recurse on the remainder of the cases.
%%
%% The various calls to lists:reverse are just to ensure that the
%% cases remain in the correct, sorted order.
cluster_split(Cases, Clust) ->
A = tl(tuple_to_list(Clust)),
Max = element(tuple_size(Clust), Clust),
L1 = lists:reverse(Cases),
L2 = lists:reverse(A),
cluster_split(Max, [], [], L1, L2).
cluster_split(0, [], Res, Cases, _Clust) ->
L = lists:reverse(Cases),
{H,_} = hd(L),
{T,_} = hd(Cases),
[{dense,hipe_icode:const_value(H),hipe_icode:const_value(T),L}|Res];
cluster_split(N, [], Res, Cases, [N|_] = Clust) ->
cluster_split(N-1, [], Res, Cases, Clust);
cluster_split(N,Sofar,Res,Cases,[N|Clust]) ->
{H,_} = hd(Sofar),
{T,_} = lists:last(Sofar),
cluster_split(N-1,[],[{dense,hipe_icode:const_value(H),hipe_icode:const_value(T),Sofar}|Res],Cases,[N|Clust]);
cluster_split(N,Sofar,Res,[C|Cases],[_|Clust]) ->
cluster_split(N,[C|Sofar],Res,Cases,Clust).
%%
%% Merge adjacent small clusters into larger sparse clusters
%%
cluster_merge([C]) -> [C];
cluster_merge([{dense,Min,Max,C}|T]) when length(C) >= ?MINFORJUMPTABLE ->
C2 = cluster_merge(T),
[{dense,Min,Max,C}|C2];
cluster_merge([{sparse,Min,_,C},{sparse,_,Max,D}|T]) ->
R = {sparse,Min,Max,C ++ D},
cluster_merge([R|T]);
cluster_merge([{sparse,Min,_,C},{dense,_,Max,D}|T]) when length(D) < ?MINFORJUMPTABLE ->
R = {sparse,Min,Max,C ++ D},
cluster_merge([R|T]);
cluster_merge([{dense,Min,_,C},{dense,_,Max,D}|T]) when length(C) < ?MINFORJUMPTABLE, length(D) < ?MINFORJUMPTABLE ->
R = {sparse,Min,Max,C ++ D},
cluster_merge([R|T]);
cluster_merge([{dense,Min,_,D},{sparse,_,Max,C}|T]) when length(D) < ?MINFORJUMPTABLE ->
R = {sparse,Min,Max,C ++ D},
cluster_merge([R|T]);
cluster_merge([A,{dense,Min,Max,C}|T]) when length(C) >= ?MINFORJUMPTABLE ->
R = cluster_merge([{dense,Min,Max,C}|T]),
[A|R].
%% Generate code to search for the correct cluster
find_cluster([{sparse,_Min,_Max,C}],VarMap,ConstTab,Options,Arg,Fail,_IcodeFail) ->
case length(C) < ?MINFORINTSEARCHTREE of
true ->
gen_small_switch_val(Arg,C,Fail,VarMap,ConstTab,Options);
_ ->
gen_search_switch_val(Arg,C,Fail,VarMap,ConstTab,Options)
end;
find_cluster([{dense,Min,_Max,C}],VarMap,ConstTab,Options,Arg,Fail,IcodeFail) ->
case length(C) < ?MINFORJUMPTABLE of
true ->
gen_small_switch_val(Arg,C,Fail,VarMap,ConstTab,Options);
_ ->
gen_jump_table(Arg,Fail,IcodeFail,VarMap,ConstTab,C,Min)
end;
find_cluster([{Density,Min,Max,C}|T],VarMap,ConstTab,Options,Arg,Fail,IcodeFail) ->
ClustLab = hipe_rtl:mk_new_label(),
NextLab = hipe_rtl:mk_new_label(),
{ClustCode,V1,C1} = find_cluster([{Density,Min,Max,C}],VarMap,ConstTab,Options,Arg,Fail,IcodeFail),
{Rest,V2,C2} = find_cluster(T,V1,C1,Options,Arg,Fail,IcodeFail),
{[
hipe_rtl:mk_branch(Arg, gt, hipe_rtl:mk_imm(hipe_tagscheme:mk_fixnum(Max)),
hipe_rtl:label_name(NextLab),
hipe_rtl:label_name(ClustLab), 0.50),
ClustLab
] ++
ClustCode ++
[NextLab] ++
Rest,
V2,C2}.
%% Generate efficient code for a linear search through the case list.
%% Only works for atoms and integer.
gen_linear_switch_val(Arg,Cases,Fail,VarMap,ConstTab,_Options) ->
{Values,_Labels} = split_cases(Cases),
{LabMap,VarMap1} = lbls_from_cases(Cases,VarMap),
Code = fast_linear_search(Arg,Values,LabMap,Fail),
{Code,VarMap1,ConstTab}.
fast_linear_search(_Arg,[],[],Fail) ->
[hipe_rtl:mk_goto(hipe_rtl:label_name(Fail))];
fast_linear_search(Arg,[Case|Cases],[Label|Labels],Fail) ->
Reg = hipe_rtl:mk_new_reg_gcsafe(),
NextLab = hipe_rtl:mk_new_label(),
C2 = fast_linear_search(Arg,Cases,Labels,Fail),
C1 =
if
is_integer(Case) ->
TVal = hipe_tagscheme:mk_fixnum(Case),
[
hipe_rtl:mk_move(Reg,hipe_rtl:mk_imm(TVal)),
hipe_rtl:mk_branch(Arg,eq,Reg,
Label,
hipe_rtl:label_name(NextLab), 0.5),
NextLab
];
is_atom(Case) ->
[
hipe_rtl:mk_load_atom(Reg,Case),
hipe_rtl:mk_branch(Arg,eq,Reg,
Label,
hipe_rtl:label_name(NextLab), 0.5),
NextLab
];
true -> % This should never happen !
?EXIT({internal_error_in_switch_val,Case})
end,
[C1,C2].
%% Generate code to search through a small cluster of integers using
%% binary search
gen_small_switch_val(Arg,Cases,Fail,VarMap,ConstTab,_Options) ->
{Values,_Labels} = split_cases(Cases),
{LabMap,VarMap1} = lbls_from_cases(Cases,VarMap),
Keys = [hipe_tagscheme:mk_fixnum(X) % Add tags to the values
|| X <- Values],
Code = inline_search(Keys, LabMap, Arg, Fail),
{Code, VarMap1, ConstTab}.
%% Generate code to search through a small cluster of atoms
gen_atom_switch_val(Arg,Cases,Fail,VarMap,ConstTab,_Options) ->
{Values, _Labels} = split_cases(Cases),
{LabMap,VarMap1} = lbls_from_cases(Cases,VarMap),
LMap = [{label,L} || L <- LabMap],
{NewConstTab,Id} = hipe_consttab:insert_sorted_block(ConstTab, Values),
{NewConstTab2,LabId} =
hipe_consttab:insert_sorted_block(NewConstTab, word, LMap, Values),
Code = inline_atom_search(0, length(Cases)-1, Id, LabId, Arg, Fail, LabMap),
{Code, VarMap1, NewConstTab2}.
%% calculate the middle position of a list (+ 1 because of 1-indexing of lists)
get_middle(List) ->
N = length(List),
N div 2 + 1.
%% get element [N1, N2] from a list
get_cases(_, 0, 0) ->
[];
get_cases([H|T], 0, N) ->
[H | get_cases(T, 0, N - 1)];
get_cases([_|T], N1, N2) ->
get_cases(T, N1 - 1, N2 - 1).
%% inline_search/4 creates RTL code for a inlined binary search.
%% It requires two sorted tables - one with the keys to search
%% through and one with the corresponding labels to jump to.
%%
%% Input:
%% KeyList - A list of keys to search through.
%% LableList - A list of labels to jump to.
%% KeyReg - A register containing the key to search for.
%% Default - A label to jump to if the key is not found.
%%
inline_search([], _LabelList, _KeyReg, _Default) -> [];
inline_search(KeyList, LabelList, KeyReg, Default) ->
%% Create some registers and labels that we need.
Reg = hipe_rtl:mk_new_reg_gcsafe(),
Lab1 = hipe_rtl:mk_new_label(),
Lab2 = hipe_rtl:mk_new_label(),
Lab3 = hipe_rtl:mk_new_label(),
Length = length(KeyList),
if
Length >= 3 ->
%% Get middle element and keys/labels before that and after
Middle_pos = get_middle(KeyList),
Middle_key = lists:nth(Middle_pos, KeyList),
Keys_beginning = get_cases(KeyList, 0, Middle_pos - 1),
Labels_beginning = get_cases(LabelList, 0, Middle_pos - 1),
Keys_ending = get_cases(KeyList, Middle_pos, Length),
Labels_ending = get_cases(LabelList, Middle_pos, Length),
%% Create the code.
%% Get the label and build it up properly
Middle_label = lists:nth(Middle_pos, LabelList),
A = [hipe_rtl:mk_move(Reg, hipe_rtl:mk_imm(Middle_key)),
hipe_rtl:mk_branch(KeyReg, lt, Reg,
hipe_rtl:label_name(Lab2),
hipe_rtl:label_name(Lab1), 0.5),
Lab1,
hipe_rtl:mk_branch(KeyReg, gt, Reg,
hipe_rtl:label_name(Lab3),
Middle_label , 0.5),
Lab2],
%% build search tree for keys less than the middle element
B = inline_search(Keys_beginning, Labels_beginning, KeyReg, Default),
%% ...and for keys bigger than the middle element
D = inline_search(Keys_ending, Labels_ending, KeyReg, Default),
%% append the code and return it
A ++ B ++ [Lab3] ++ D;
Length =:= 2 ->
%% get the first and second elements and theirs labels
Key_first = hd(KeyList),
First_label = hd(LabelList),
%% Key_second = hipe_tagscheme:mk_fixnum(lists:nth(2, KeyList)),
Key_second = lists:nth(2, KeyList),
Second_label = lists:nth(2, LabelList),
NewLab = hipe_rtl:mk_new_label(),
%% compare them
A = [hipe_rtl:mk_move(Reg,hipe_rtl:mk_imm(Key_first)),
hipe_rtl:mk_branch(KeyReg, eq, Reg,
First_label,
hipe_rtl:label_name(NewLab) , 0.5),
NewLab],
B = [hipe_rtl:mk_move(Reg,hipe_rtl:mk_imm(Key_second)),
hipe_rtl:mk_branch(KeyReg, eq, Reg,
Second_label,
hipe_rtl:label_name(Default) , 0.5)],
A ++ B;
Length =:= 1 ->
Key = hd(KeyList),
Label = hd(LabelList),
[hipe_rtl:mk_move(Reg,hipe_rtl:mk_imm(Key)),
hipe_rtl:mk_branch(KeyReg, eq, Reg,
Label,
hipe_rtl:label_name(Default) , 0.5)]
end.
inline_atom_search(Start, End, Block, LBlock, KeyReg, Default, Labels) ->
Reg = hipe_rtl:mk_new_reg_gcsafe(),
Length = (End - Start) + 1,
if
Length >= 3 ->
Lab1 = hipe_rtl:mk_new_label(),
Lab2 = hipe_rtl:mk_new_label(),
Lab3 = hipe_rtl:mk_new_label(),
Lab4 = hipe_rtl:mk_new_label(),
Mid = ((End-Start) div 2)+Start,
End1 = Mid-1,
Start1 = Mid+1,
A = [
hipe_rtl:mk_load_word_index(Reg,Block,Mid),
hipe_rtl:mk_branch(KeyReg, lt, Reg,
hipe_rtl:label_name(Lab2),
hipe_rtl:label_name(Lab1), 0.5),
Lab1,
hipe_rtl:mk_branch(KeyReg, gt, Reg,
hipe_rtl:label_name(Lab3),
hipe_rtl:label_name(Lab4), 0.5),
Lab4,
hipe_rtl:mk_goto_index(LBlock, Mid, Labels),
Lab2
],
B = [inline_atom_search(Start,End1,Block,LBlock,KeyReg,Default,Labels)],
C = [inline_atom_search(Start1,End,Block,LBlock,KeyReg,Default,Labels)],
A ++ B ++ [Lab3] ++ C;
Length =:= 2 ->
L1 = hipe_rtl:mk_new_label(),
L2 = hipe_rtl:mk_new_label(),
L3 = hipe_rtl:mk_new_label(),
[
hipe_rtl:mk_load_word_index(Reg,Block,Start),
hipe_rtl:mk_branch(KeyReg,eq,Reg,
hipe_rtl:label_name(L1),
hipe_rtl:label_name(L2), 0.5),
L1,
hipe_rtl:mk_goto_index(LBlock,Start,Labels),
L2,
hipe_rtl:mk_load_word_index(Reg,Block,End),
hipe_rtl:mk_branch(KeyReg,eq,Reg,
hipe_rtl:label_name(L3),
hipe_rtl:label_name(Default), 0.5),
L3,
hipe_rtl:mk_goto_index(LBlock, End, Labels)
];
Length =:= 1 ->
NewLab = hipe_rtl:mk_new_label(),
[
hipe_rtl:mk_load_word_index(Reg,Block,Start),
hipe_rtl:mk_branch(KeyReg, eq, Reg,
hipe_rtl:label_name(NewLab),
hipe_rtl:label_name(Default), 0.9),
NewLab,
hipe_rtl:mk_goto_index(LBlock, Start, Labels)
]
end.
%% Create a jumptable
gen_jump_table(Arg,Fail,IcodeFail,VarMap,ConstTab,Cases,Min) ->
%% Map is a rtl mapping of Dense
{Max,DenseTbl} = dense_interval(Cases,Min,IcodeFail),
{Map,VarMap2} = lbls_from_cases(DenseTbl,VarMap),
%% Make some labels and registers that we need.
BelowLab = hipe_rtl:mk_new_label(),
UntaggedR = hipe_rtl:mk_new_reg_gcsafe(),
StartR = hipe_rtl:mk_new_reg_gcsafe(),
%% Generate the code to do the switch...
{[
%% Untag the index.
hipe_tagscheme:untag_fixnum(UntaggedR, Arg)|
%% Check that the index is within Min and Max.
case Min of
0 -> %% First element is 0 this is simple.
[hipe_rtl:mk_branch(UntaggedR, gtu, hipe_rtl:mk_imm(Max),
hipe_rtl:label_name(Fail),
hipe_rtl:label_name(BelowLab), 0.01),
BelowLab,
%% StartR contains the index into the jumptable
hipe_rtl:mk_switch(UntaggedR, Map)];
_ -> %% First element is not 0
[hipe_rtl:mk_alu(StartR, UntaggedR, sub,
hipe_rtl:mk_imm(Min)),
hipe_rtl:mk_branch(StartR, gtu, hipe_rtl:mk_imm(Max-Min),
hipe_rtl:label_name(Fail),
hipe_rtl:label_name(BelowLab), 0.01),
BelowLab,
%% StartR contains the index into the jumptable
hipe_rtl:mk_switch(StartR, Map)]
end],
VarMap2,
ConstTab}.
%% Generate the jumptable for Cases while filling in unused positions
%% with the fail label
dense_interval(Cases, Min, IcodeFail) ->
dense_interval(Cases, Min, IcodeFail, 0, 0).
dense_interval([Pair = {Const,_}|Rest], Pos, Fail, Range, NoEntries) ->
Val = hipe_icode:const_value(Const),
if
Pos < Val ->
{Max, Res} =
dense_interval([Pair|Rest], Pos+1, Fail, Range+1, NoEntries),
{Max,[{hipe_icode:mk_const(Pos), Fail}|Res]};
true ->
{Max, Res} = dense_interval(Rest, Pos+1, Fail, Range+1, NoEntries+1),
{Max, [Pair | Res]}
end;
dense_interval([], Max, _, _, _) ->
{Max-1, []}.
%%-------------------------------------------------------------------------
%% switch_val without jumptable
%%
gen_slow_switch_val(I, VarMap, ConstTab, Options) ->
Is = rewrite_switch_val(I),
?IF_DEBUG_LEVEL(3,?msg("Switch: ~w\n", [Is]), no_debug),
hipe_icode2rtl:translate_instrs(Is, VarMap, ConstTab, Options).
rewrite_switch_val(I) ->
Var = hipe_icode:switch_val_term(I),
Fail = hipe_icode:switch_val_fail_label(I),
Cases = hipe_icode:switch_val_cases(I),
rewrite_switch_val_cases(Cases, Fail, Var).
rewrite_switch_val_cases([{C,L}|Cases], Fail, Arg) ->
Tmp = hipe_icode:mk_new_var(),
NextLab = hipe_icode:mk_new_label(),
[hipe_icode:mk_move(Tmp, C),
hipe_icode:mk_if(op_exact_eqeq_2, [Arg, Tmp], L,
hipe_icode:label_name(NextLab)),
NextLab |
rewrite_switch_val_cases(Cases, Fail, Arg)];
rewrite_switch_val_cases([], Fail, _Arg) ->
[hipe_icode:mk_goto(Fail)].
%%-------------------------------------------------------------------------
%% switch_val with binary search jumptable
%%
gen_search_switch_val(Arg, Cases, Default, VarMap, ConstTab, _Options) ->
ValTableR = hipe_rtl:mk_new_reg_gcsafe(),
{Values,_Labels} = split_cases(Cases),
{NewConstTab,Id} = hipe_consttab:insert_sorted_block(ConstTab, Values),
{LabMap,VarMap1} = lbls_from_cases(Cases,VarMap),
Code =
[hipe_rtl:mk_load_address(ValTableR, Id, constant)|
tab(Values,LabMap,Arg,ValTableR,Default)],
{Code, VarMap1, NewConstTab}.
%%-------------------------------------------------------------------------
%%
%% tab/5 creates RTL code for a binary search.
%% It requires two sorted tables one with the keys to search
%% through and one with the corresponding labels to jump to.
%%
%% The implementation is derived from John Bentlys
%% Programming Pearls.
%%
%% Input:
%% KeyList - A list of keys to search through.
%% (Just used to calculate the number of elements.)
%% LableList - A list of labels to jump to.
%% KeyReg - A register containing the key to search for.
%% TablePntrReg - A register containing a pointer to the
%% tables with keys
%% Default - A lable to jump to if the key is not found.
%%
%% Example:
%% KeyTbl: < a, b, d, f, h, i, z >
%% Lbls: < 5, 3, 2, 4, 1, 7, 6 >
%% Default: 8
%% KeyReg: v37
%% TablePntrReg: r41
%%
%% should give code like:
%% r41 <- KeyTbl
%% r42 <- 0
%% r43 <- [r41+16]
%% if (r43 gt v37) then L17 (0.50) else L16
%% L16:
%% r42 <- 16
%% goto L17
%% L17:
%% r46 <- r42 add 16
%% r45 <- [r41+r46]
%% if (r45 gt v37) then L21 (0.50) else L20
%% L20:
%% r42 <- r46
%% goto L21
%% L21:
%% r48 <- r42 add 8
%% r47 <- [r41+r48]
%% if (r47 gt v37) then L23 (0.50) else L22
%% L22:
%% r42 <- r48
%% goto L23
%% L23:
%% r50 <- r42 add 4
%% r49 <- [r41+r50]
%% if (r49 gt v37) then L25 (0.50) else L24
%% L24:
%% r42 <- r42 add 4
%% goto L25
%% L25:
%% if (r42 gt 28) then L6 (0.50) else L18
%% L18:
%% r44 <- [r41+r42]
%% if (r44 eq v37) then L19 (0.90) else L8
%% L19:
%% r42 <- r42 sra 2
%% switch (r42) <L5, L3, L2, L4, L1,
%% L7, L6>
%%
%% The search is done like a rolled out binary search,
%% but instead of starting in the middle we start at
%% the power of two closest above the middle.
%%
%% We let IndexReg point to the lower bound of our
%% search, and then we speculatively look at a
%% position at IndexReg + I where I is a power of 2.
%%
%% Example: Looking for 'h' in
%% KeyTbl: < a, b, d, f, h, i, z >
%%
%% We start with IndexReg=0 and I=4
%% < a, b, d, f, h, i, z >
%% ^ ^
%% IndexReg + I
%%
%% 'f' < 'h' so we add I to IndexReg and divide I with 2
%% IndexReg=4 and I=2
%% < a, b, d, f, h, i, z >
%% ^ ^
%% IndexReg + I
%%
%% 'i' > 'h' so we keep IndexReg and divide I with 2
%% IndexReg=4 and I=1
%% < a, b, d, f, h, i, z >
%% ^ ^
%% IndexReg+ I
%% Now we have found 'h' so we add I to IndexReg -> 5
%% And we can load switch to the label at position 5 in
%% the label table.
%%
%% Now since the wordsize is 4 all numbers above are
%% Multiples of 4.
tab(KeyList, LabelList, KeyReg, TablePntrReg, Default) ->
%% Calculate the size of the table:
%% the number of keys * wordsize
LastOffset = (length(KeyList)-1)*?WORDSIZE,
%% Calculate the power of two closest to the size of the table.
Pow2 = 1 bsl trunc(math:log(LastOffset) / math:log(2)),
%% Create some registers and lables that we need
IndexReg = hipe_rtl:mk_new_reg_gcsafe(),
Temp = hipe_rtl:mk_new_reg_gcsafe(),
Temp2 = hipe_rtl:mk_new_reg_gcsafe(),
Lab1 = hipe_rtl:mk_new_label(),
Lab2 = hipe_rtl:mk_new_label(),
Lab3 = hipe_rtl:mk_new_label(),
Lab4 = hipe_rtl:mk_new_label(),
%% Calculate the position to start looking at
Init = (LastOffset)-Pow2,
%% Create the code
[
hipe_rtl:mk_move(IndexReg,hipe_rtl:mk_imm(0)),
hipe_rtl:mk_load(Temp,TablePntrReg,hipe_rtl:mk_imm(Init)),
hipe_rtl:mk_branch(Temp, geu, KeyReg,
hipe_rtl:label_name(Lab2),
hipe_rtl:label_name(Lab1), 0.5),
Lab1,
hipe_rtl:mk_alu(IndexReg, IndexReg, add, hipe_rtl:mk_imm(Init+?WORDSIZE)),
hipe_rtl:mk_goto(hipe_rtl:label_name(Lab2)),
Lab2] ++
step(Pow2 div 2, TablePntrReg, IndexReg, KeyReg) ++
[hipe_rtl:mk_branch(IndexReg, gt, hipe_rtl:mk_imm(LastOffset),
hipe_rtl:label_name(Default),
hipe_rtl:label_name(Lab3), 0.5),
Lab3,
hipe_rtl:mk_load(Temp2,TablePntrReg,IndexReg),
hipe_rtl:mk_branch(Temp2, eq, KeyReg,
hipe_rtl:label_name(Lab4),
hipe_rtl:label_name(Default), 0.9),
Lab4,
hipe_rtl:mk_alu(IndexReg, IndexReg, sra,
hipe_rtl:mk_imm(hipe_rtl_arch:log2_word_size())),
hipe_rtl:mk_sorted_switch(IndexReg, LabelList, KeyList)
].
step(I,TablePntrReg,IndexReg,KeyReg) ->
Temp = hipe_rtl:mk_new_reg_gcsafe(),
TempIndex = hipe_rtl:mk_new_reg_gcsafe(),
Lab1 = hipe_rtl:mk_new_label(),
Lab2 = hipe_rtl:mk_new_label(),
[hipe_rtl:mk_alu(TempIndex, IndexReg, add, hipe_rtl:mk_imm(I)),
hipe_rtl:mk_load(Temp,TablePntrReg,TempIndex),
hipe_rtl:mk_branch(Temp, gtu, KeyReg,
hipe_rtl:label_name(Lab2),
hipe_rtl:label_name(Lab1) , 0.5),
Lab1] ++
case ?WORDSIZE of
I -> %% Recursive base case
[hipe_rtl:mk_alu(IndexReg, IndexReg, add, hipe_rtl:mk_imm(I)),
hipe_rtl:mk_goto(hipe_rtl:label_name(Lab2)),
Lab2
];
_ -> %% Recursion case
[hipe_rtl:mk_move(IndexReg, TempIndex),
hipe_rtl:mk_goto(hipe_rtl:label_name(Lab2)),
Lab2
| step(I div 2, TablePntrReg, IndexReg, KeyReg)
]
end.
%%-------------------------------------------------------------------------
lbls_from_cases([{_,L}|Rest], VarMap) ->
{Map,VarMap1} = lbls_from_cases(Rest, VarMap),
{RtlL, VarMap2} = hipe_rtl_varmap:icode_label2rtl_label(L,VarMap1),
%% {[{label,hipe_rtl:label_name(RtlL)}|Map],VarMap2};
{[hipe_rtl:label_name(RtlL)|Map],VarMap2};
lbls_from_cases([], VarMap) ->
{[], VarMap}.
%%-------------------------------------------------------------------------
split_cases(L) ->
split_cases(L, [], []).
split_cases([], Vs, Ls) -> {lists:reverse(Vs),lists:reverse(Ls)};
split_cases([{V,L}|Rest], Vs, Ls) ->
split_cases(Rest, [hipe_icode:const_value(V)|Vs], [L|Ls]).
%%-------------------------------------------------------------------------
%%
%% {switch_tuple_arity,X,Fail,N,[{A1,L1},...,{AN,LN}]}
%%
%% if not boxed(X) goto Fail
%% Hdr := *boxed_val(X)
%% switch_int(Hdr,Fail,[{H(A1),L1},...,{H(AN),LN}])
%% where H(Ai) = make_arityval(Ai)
%%
%%-------------------------------------------------------------------------
gen_switch_tuple(I, Map, ConstTab, _Options) ->
Var = hipe_icode:switch_tuple_arity_term(I),
{X, Map1} = hipe_rtl_varmap:icode_var2rtl_var(Var, Map),
Fail0 = hipe_icode:switch_tuple_arity_fail_label(I),
{Fail1, Map2} = hipe_rtl_varmap:icode_label2rtl_label(Fail0, Map1),
FailLab = hipe_rtl:label_name(Fail1),
{Cases, Map3} =
lists:foldr(fun({A,L}, {Rest,M}) ->
{L1,M1} = hipe_rtl_varmap:icode_label2rtl_label(L, M),
L2 = hipe_rtl:label_name(L1),
A1 = hipe_icode:const_value(A),
H1 = hipe_tagscheme:mk_arityval(A1),
{[{H1,L2}|Rest], M1} end,
{[], Map2},
hipe_icode:switch_tuple_arity_cases(I)),
Hdr = hipe_rtl:mk_new_reg_gcsafe(),
IsBoxedLab = hipe_rtl:mk_new_label(),
{[hipe_tagscheme:test_is_boxed(X, hipe_rtl:label_name(IsBoxedLab),
FailLab, 0.9),
IsBoxedLab,
hipe_tagscheme:get_header(Hdr, X) |
gen_switch_int(Hdr, FailLab, Cases)],
Map3, ConstTab}.
%%
%% RTL-level switch-on-int
%%
gen_switch_int(X, FailLab, [{C,L}|Rest]) ->
NextLab = hipe_rtl:mk_new_label(),
[hipe_rtl:mk_branch(X, eq, hipe_rtl:mk_imm(C), L,
hipe_rtl:label_name(NextLab), 0.5),
NextLab |
gen_switch_int(X, FailLab, Rest)];
gen_switch_int(_, FailLab, []) ->
[hipe_rtl:mk_goto(FailLab)].
|