-
Notifications
You must be signed in to change notification settings - Fork 104
/
c_backend.ml
2449 lines (2209 loc) · 104 KB
/
c_backend.ml
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
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
(****************************************************************************)
(* Sail *)
(* *)
(* Sail and the Sail architecture models here, comprising all files and *)
(* directories except the ASL-derived Sail code in the aarch64 directory, *)
(* are subject to the BSD two-clause licence below. *)
(* *)
(* The ASL derived parts of the ARMv8.3 specification in *)
(* aarch64/no_vector and aarch64/full are copyright ARM Ltd. *)
(* *)
(* Copyright (c) 2013-2021 *)
(* Kathyrn Gray *)
(* Shaked Flur *)
(* Stephen Kell *)
(* Gabriel Kerneis *)
(* Robert Norton-Wright *)
(* Christopher Pulte *)
(* Peter Sewell *)
(* Alasdair Armstrong *)
(* Brian Campbell *)
(* Thomas Bauereiss *)
(* Anthony Fox *)
(* Jon French *)
(* Dominic Mulligan *)
(* Stephen Kell *)
(* Mark Wassell *)
(* Alastair Reid (Arm Ltd) *)
(* *)
(* All rights reserved. *)
(* *)
(* This work was partially supported by EPSRC grant EP/K008528/1 <a *)
(* href="http://www.cl.cam.ac.uk/users/pes20/rems">REMS: Rigorous *)
(* Engineering for Mainstream Systems</a>, an ARM iCASE award, EPSRC IAA *)
(* KTF funding, and donations from Arm. This project has received *)
(* funding from the European Research Council (ERC) under the European *)
(* Union’s Horizon 2020 research and innovation programme (grant *)
(* agreement No 789108, ELVER). *)
(* *)
(* This software was developed by SRI International and the University of *)
(* Cambridge Computer Laboratory (Department of Computer Science and *)
(* Technology) under DARPA/AFRL contracts FA8650-18-C-7809 ("CIFV") *)
(* and FA8750-10-C-0237 ("CTSRD"). *)
(* *)
(* Redistribution and use in source and binary forms, with or without *)
(* modification, are permitted provided that the following conditions *)
(* are met: *)
(* 1. Redistributions of source code must retain the above copyright *)
(* notice, this list of conditions and the following disclaimer. *)
(* 2. Redistributions in binary form must reproduce the above copyright *)
(* notice, this list of conditions and the following disclaimer in *)
(* the documentation and/or other materials provided with the *)
(* distribution. *)
(* *)
(* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' *)
(* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED *)
(* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A *)
(* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR *)
(* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, *)
(* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT *)
(* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF *)
(* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND *)
(* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, *)
(* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT *)
(* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF *)
(* SUCH DAMAGE. *)
(****************************************************************************)
open Libsail
open Ast
open Ast_defs
open Ast_util
open Jib
open Jib_compile
open Jib_util
open Type_check
open PPrint
open Value2
open Anf
module Big_int = Nat_big_num
let opt_static = ref false
let static () = if !opt_static then "static " else ""
let opt_no_main = ref false
let opt_no_lib = ref false
let opt_no_rts = ref false
let opt_prefix = ref "z"
let opt_extra_params = ref None
let opt_extra_arguments = ref None
let opt_branch_coverage = ref None
let extra_params () =
match !opt_extra_params with
| Some str -> str ^ ", "
| _ -> ""
let extra_arguments is_extern =
match !opt_extra_arguments with
| Some str when not is_extern -> str ^ ", "
| _ -> ""
(* Optimization flags *)
let optimize_primops = ref false
let optimize_hoist_allocations = ref false
let optimize_struct_updates = ref false
let optimize_alias = ref false
let optimize_fixed_int = ref false
let optimize_fixed_bits = ref false
let (gensym, _) = symbol_generator "cb"
let ngensym () = name (gensym ())
let c_error ?loc:(l=Parse_ast.Unknown) message =
raise (Reporting.err_general l ("\nC backend: " ^ message))
let zencode_id id = Util.zencode_string (string_of_id id)
let zencode_uid (id, ctyps) =
match ctyps with
| [] -> Util.zencode_string (string_of_id id)
| _ -> Util.zencode_string (string_of_id id ^ "#" ^ Util.string_of_list "_" string_of_ctyp ctyps)
let ctor_bindings = List.fold_left (fun map (id, ctyp) -> UBindings.add id ctyp map) UBindings.empty
(**************************************************************************)
(* 2. Converting sail types to C types *)
(**************************************************************************)
let max_int n = Big_int.pred (Big_int.pow_int_positive 2 (n - 1))
let min_int n = Big_int.negate (Big_int.pow_int_positive 2 (n - 1))
(** This function is used to split types into those we allocate on the
stack, versus those which need to live on the heap, or otherwise
require some additional memory management *)
let rec is_stack_ctyp ctyp = match ctyp with
| CT_fbits _ | CT_sbits _ | CT_bit | CT_unit | CT_bool | CT_enum _ -> true
| CT_fint n -> n <= 64
| CT_lint when !optimize_fixed_int -> true
| CT_lint -> false
| CT_lbits _ when !optimize_fixed_bits -> true
| CT_lbits _ -> false
| CT_real | CT_string | CT_list _ | CT_vector _ | CT_fvector _ -> false
| CT_struct (_, fields) -> List.for_all (fun (_, ctyp) -> is_stack_ctyp ctyp) fields
| CT_variant (_, ctors) -> false (* List.for_all (fun (_, ctyp) -> is_stack_ctyp ctyp) ctors *) (* FIXME *)
| CT_tup ctyps -> List.for_all is_stack_ctyp ctyps
| CT_ref ctyp -> true
| CT_poly _ -> true
| CT_float _ -> true
| CT_rounding_mode -> true
| CT_constant n -> Big_int.less_equal (min_int 64) n && Big_int.greater_equal n (max_int 64)
let v_mask_lower i = V_lit (VL_bits (Util.list_init i (fun _ -> Sail2_values.B1), true), CT_fbits (i, true))
let hex_char =
let open Sail2_values in
function
| '0' -> [B0; B0; B0; B0]
| '1' -> [B0; B0; B0; B1]
| '2' -> [B0; B0; B1; B0]
| '3' -> [B0; B0; B1; B1]
| '4' -> [B0; B1; B0; B0]
| '5' -> [B0; B1; B0; B1]
| '6' -> [B0; B1; B1; B0]
| '7' -> [B0; B1; B1; B1]
| '8' -> [B1; B0; B0; B0]
| '9' -> [B1; B0; B0; B1]
| 'A' | 'a' -> [B1; B0; B1; B0]
| 'B' | 'b' -> [B1; B0; B1; B1]
| 'C' | 'c' -> [B1; B1; B0; B0]
| 'D' | 'd' -> [B1; B1; B0; B1]
| 'E' | 'e' -> [B1; B1; B1; B0]
| 'F' | 'f' -> [B1; B1; B1; B1]
| _ -> failwith "Invalid hex character"
let literal_to_fragment (L_aux (l_aux, _) as lit) =
match l_aux with
| L_num n when Big_int.less_equal (min_int 64) n && Big_int.less_equal n (max_int 64) ->
Some (V_lit (VL_int n, CT_fint 64))
| L_hex str when String.length str <= 16 ->
let padding = 16 - String.length str in
let padding = Util.list_init padding (fun _ -> Sail2_values.B0) in
let content = Util.string_to_list str |> List.map hex_char |> List.concat in
Some (V_lit (VL_bits (padding @ content, true), CT_fbits (String.length str * 4, true)))
| L_unit -> Some (V_lit (VL_unit, CT_unit))
| L_true -> Some (V_lit (VL_bool true, CT_bool))
| L_false -> Some (V_lit (VL_bool false, CT_bool))
| _ -> None
module C_config(Opts : sig val branch_coverage : out_channel option end) : Config = struct
(** Convert a sail type into a C-type. This function can be quite
slow, because it uses ctx.local_env and SMT to analyse the Sail
types and attempts to fit them into the smallest possible C
types, provided ctx.optimize_smt is true (default) **)
let rec convert_typ ctx typ =
let Typ_aux (typ_aux, l) as typ = Env.expand_synonyms ctx.local_env typ in
match typ_aux with
| Typ_id id when string_of_id id = "bit" -> CT_bit
| Typ_id id when string_of_id id = "bool" -> CT_bool
| Typ_id id when string_of_id id = "int" -> CT_lint
| Typ_id id when string_of_id id = "nat" -> CT_lint
| Typ_id id when string_of_id id = "unit" -> CT_unit
| Typ_id id when string_of_id id = "string" -> CT_string
| Typ_id id when string_of_id id = "real" -> CT_real
| Typ_app (id, _) when string_of_id id = "atom_bool" -> CT_bool
| Typ_app (id, args) when string_of_id id = "itself" ->
convert_typ ctx (Typ_aux (Typ_app (mk_id "atom", args), l))
| Typ_app (id, _) when string_of_id id = "range" || string_of_id id = "atom" || string_of_id id = "implicit" ->
begin match destruct_range Env.empty typ with
| None -> assert false (* Checked if range type in guard *)
| Some (kids, constr, n, m) ->
let ctx = { ctx with local_env = add_existential Parse_ast.Unknown (List.map (mk_kopt K_int) kids) constr ctx.local_env }in
match nexp_simp n, nexp_simp m with
| Nexp_aux (Nexp_constant n, _), Nexp_aux (Nexp_constant m, _)
when Big_int.less_equal (min_int 64) n && Big_int.less_equal m (max_int 64) ->
CT_fint 64
| n, m ->
if prove __POS__ ctx.local_env (nc_lteq (nconstant (min_int 64)) n) && prove __POS__ ctx.local_env (nc_lteq m (nconstant (max_int 64))) then
CT_fint 64
else
CT_lint
end
| Typ_app (id, [A_aux (A_typ typ, _)]) when string_of_id id = "list" ->
CT_list (ctyp_suprema (convert_typ ctx typ))
(* When converting a sail bitvector type into C, we have three options in order of efficiency:
- If the length is obviously static and smaller than 64, use the fixed bits type (aka uint64_t), fbits.
- If the length is less than 64, then use a small bits type, sbits.
- If the length may be larger than 64, use a large bits type lbits. *)
| Typ_app (id, [A_aux (A_nexp n, _);
A_aux (A_order ord, _)])
when string_of_id id = "bitvector" ->
let direction = true in (* match ord with Ord_aux (Ord_dec, _) -> true | Ord_aux (Ord_inc, _) -> false | _ -> assert false in *)
begin match nexp_simp n with
| Nexp_aux (Nexp_constant n, _) when Big_int.less_equal n (Big_int.of_int 64) -> CT_fbits (Big_int.to_int n, direction)
| n when prove __POS__ ctx.local_env (nc_lteq n (nint 64)) -> CT_sbits (64, direction)
| _ -> CT_lbits direction
end
| Typ_app (id, [A_aux (A_nexp n, _);
A_aux (A_order ord, _);
A_aux (A_typ typ, _)])
when string_of_id id = "vector" ->
let direction = true in (* let direction = match ord with Ord_aux (Ord_dec, _) -> true | Ord_aux (Ord_inc, _) -> false | _ -> assert false in *)
CT_vector (direction, convert_typ ctx typ)
| Typ_app (id, [A_aux (A_typ typ, _)]) when string_of_id id = "register" ->
CT_ref (convert_typ ctx typ)
| Typ_id id when Bindings.mem id ctx.records -> CT_struct (id, Bindings.find id ctx.records |> snd |> UBindings.bindings)
| Typ_app (id, typ_args) when Bindings.mem id ctx.records ->
let (typ_params, fields) = Bindings.find id ctx.records in
let quants =
List.fold_left2 (fun quants typ_param typ_arg ->
match typ_arg with
| A_aux (A_typ typ, _) ->
KBindings.add typ_param (convert_typ ctx typ) quants
| _ ->
Reporting.unreachable l __POS__ "Non-type argument for record here should be impossible"
) ctx.quants typ_params (List.filter is_typ_arg_typ typ_args)
in
let fix_ctyp ctyp = if is_polymorphic ctyp then ctyp_suprema (subst_poly quants ctyp) else ctyp in
CT_struct (id, UBindings.map fix_ctyp fields |> UBindings.bindings)
| Typ_id id when Bindings.mem id ctx.variants -> CT_variant (id, Bindings.find id ctx.variants |> snd |> UBindings.bindings)
| Typ_app (id, typ_args) when Bindings.mem id ctx.variants ->
let (typ_params, ctors) = Bindings.find id ctx.variants in
let quants =
List.fold_left2 (fun quants typ_param typ_arg ->
match typ_arg with
| A_aux (A_typ typ, _) ->
KBindings.add typ_param (convert_typ ctx typ) quants
| _ ->
Reporting.unreachable l __POS__ "Non-type argument for variant here should be impossible"
) ctx.quants typ_params (List.filter is_typ_arg_typ typ_args)
in
let fix_ctyp ctyp = if is_polymorphic ctyp then ctyp_suprema (subst_poly quants ctyp) else ctyp in
CT_variant (id, UBindings.map fix_ctyp ctors |> UBindings.bindings)
| Typ_id id when Bindings.mem id ctx.enums -> CT_enum (id, Bindings.find id ctx.enums |> IdSet.elements)
| Typ_tup typs -> CT_tup (List.map (convert_typ ctx) typs)
| Typ_exist _ ->
(* Use Type_check.destruct_exist when optimising with SMT, to
ensure that we don't cause any type variable clashes in
local_env, and that we can optimize the existential based
upon it's constraints. *)
begin match destruct_exist typ with
| Some (kids, nc, typ) ->
let env = add_existential l kids nc ctx.local_env in
convert_typ { ctx with local_env = env } typ
| None -> raise (Reporting.err_unreachable l __POS__ "Existential cannot be destructured!")
end
| Typ_var kid -> CT_poly kid
| _ -> c_error ~loc:l ("No C type for type " ^ string_of_typ typ)
let is_stack_typ ctx typ = is_stack_ctyp (convert_typ ctx typ)
let is_fbits_typ ctx typ =
match convert_typ ctx typ with
| CT_fbits _ -> true
| _ -> false
let is_sbits_typ ctx typ =
match convert_typ ctx typ with
| CT_sbits _ -> true
| _ -> false
(**************************************************************************)
(* 3. Optimization of primitives and literals *)
(**************************************************************************)
let c_literals ctx =
let rec c_literal env l = function
| AV_lit (lit, typ) as v when is_stack_ctyp (convert_typ { ctx with local_env = env } typ) ->
begin
match literal_to_fragment lit with
| Some cval -> AV_cval (cval, typ)
| None -> v
end
| AV_tuple avals -> AV_tuple (List.map (c_literal env l) avals)
| v -> v
in
map_aval c_literal
let rec is_bitvector = function
| [] -> true
| AV_lit (L_aux (L_zero, _), _) :: avals -> is_bitvector avals
| AV_lit (L_aux (L_one, _), _) :: avals -> is_bitvector avals
| _ :: _ -> false
let value_of_aval_bit = function
| AV_lit (L_aux (L_zero, _), _) -> Sail2_values.B0
| AV_lit (L_aux (L_one, _), _) -> Sail2_values.B1
| _ -> assert false
(** Used to make sure the -Ofixed_int and -Ofixed_bits don't
interfere with assumptions made about optimizations in the common
case. *)
let never_optimize = function
| CT_lbits _ | CT_lint -> true
| _ -> false
let rec c_aval ctx = function
| AV_lit (lit, typ) as v ->
begin
match literal_to_fragment lit with
| Some cval -> AV_cval (cval, typ)
| None -> v
end
| AV_cval (cval, typ) -> AV_cval (cval, typ)
(* An id can be converted to a C fragment if it's type can be
stack-allocated. *)
| AV_id (id, lvar) as v ->
begin
match lvar with
| Local (_, typ) ->
let ctyp = convert_typ ctx typ in
if is_stack_ctyp ctyp && not (never_optimize ctyp) then
begin
try
(* We need to check that id's type hasn't changed due to flow typing *)
let _, ctyp' = Bindings.find id ctx.locals in
if ctyp_equal ctyp ctyp' then
AV_cval (V_id (name_or_global ctx id, ctyp), typ)
else
(* id's type changed due to flow typing, so it's
really still heap allocated! *)
v
with
(* Hack: Assuming global letbindings don't change from flow typing... *)
Not_found -> AV_cval (V_id (name_or_global ctx id, ctyp), typ)
end
else
v
| Register typ ->
let ctyp = convert_typ ctx typ in
if is_stack_ctyp ctyp && not (never_optimize ctyp) then
AV_cval (V_id (global id, ctyp), typ)
else
v
| _ -> v
end
| AV_vector (v, typ) when is_bitvector v && List.length v <= 64 ->
let bitstring = VL_bits (List.map value_of_aval_bit v, true) in
AV_cval (V_lit (bitstring, CT_fbits (List.length v, true)), typ)
| AV_tuple avals -> AV_tuple (List.map (c_aval ctx) avals)
| aval -> aval
let c_fragment = function
| AV_cval (cval, _) -> cval
| _ -> assert false
(* Map over all the functions in an aexp. *)
let rec analyze_functions ctx f (AE_aux (aexp, env, l)) =
let ctx = { ctx with local_env = env } in
let aexp = match aexp with
| AE_app (id, vs, typ) -> f ctx id vs typ
| AE_cast (aexp, typ) -> AE_cast (analyze_functions ctx f aexp, typ)
| AE_assign (alexp, aexp) -> AE_assign (alexp, analyze_functions ctx f aexp)
| AE_short_circuit (op, aval, aexp) -> AE_short_circuit (op, aval, analyze_functions ctx f aexp)
| AE_let (mut, id, typ1, aexp1, (AE_aux (_, env2, _) as aexp2), typ2) ->
let aexp1 = analyze_functions ctx f aexp1 in
(* Use aexp2's environment because it will contain constraints for id *)
let ctyp1 = convert_typ { ctx with local_env = env2 } typ1 in
let ctx = { ctx with locals = Bindings.add id (mut, ctyp1) ctx.locals } in
AE_let (mut, id, typ1, aexp1, analyze_functions ctx f aexp2, typ2)
| AE_block (aexps, aexp, typ) -> AE_block (List.map (analyze_functions ctx f) aexps, analyze_functions ctx f aexp, typ)
| AE_if (aval, aexp1, aexp2, typ) ->
AE_if (aval, analyze_functions ctx f aexp1, analyze_functions ctx f aexp2, typ)
| AE_loop (loop_typ, aexp1, aexp2) -> AE_loop (loop_typ, analyze_functions ctx f aexp1, analyze_functions ctx f aexp2)
| AE_for (id, aexp1, aexp2, aexp3, order, aexp4) ->
let aexp1 = analyze_functions ctx f aexp1 in
let aexp2 = analyze_functions ctx f aexp2 in
let aexp3 = analyze_functions ctx f aexp3 in
let aexp4 = analyze_functions ctx f aexp4 in
(* Currently we assume that loop indexes are always safe to put into an int64 *)
let ctx = { ctx with locals = Bindings.add id (Immutable, CT_fint 64) ctx.locals } in
AE_for (id, aexp1, aexp2, aexp3, order, aexp4)
| AE_case (aval, cases, typ) ->
let analyze_case (AP_aux (_, env, _) as pat, aexp1, aexp2) =
let pat_bindings = Bindings.bindings (apat_types pat) in
let ctx = { ctx with local_env = env } in
let ctx =
List.fold_left (fun ctx (id, typ) -> { ctx with locals = Bindings.add id (Immutable, convert_typ ctx typ) ctx.locals }) ctx pat_bindings
in
pat, analyze_functions ctx f aexp1, analyze_functions ctx f aexp2
in
AE_case (aval, List.map analyze_case cases, typ)
| AE_try (aexp, cases, typ) ->
AE_try (analyze_functions ctx f aexp, List.map (fun (pat, aexp1, aexp2) -> pat, analyze_functions ctx f aexp1, analyze_functions ctx f aexp2) cases, typ)
| AE_field _ | AE_record_update _ | AE_val _ | AE_return _ | AE_exit _ | AE_throw _ as v -> v
in
AE_aux (aexp, env, l)
let analyze_primop' ctx id args typ =
let no_change = AE_app (id, args, typ) in
let args = List.map (c_aval ctx) args in
let extern = if ctx_is_extern id ctx then ctx_get_extern id ctx else failwith "Not extern" in
let v_one = V_lit (VL_int (Big_int.of_int 1), CT_fint 64) in
let v_int n = V_lit (VL_int (Big_int.of_int n), CT_fint 64) in
match extern, args with
| "eq_bits", [AV_cval (v1, _); AV_cval (v2, _)] when ctyp_equal (cval_ctyp v1) (cval_ctyp v2) ->
begin match cval_ctyp v1 with
| CT_fbits _ | CT_sbits _ ->
AE_val (AV_cval (V_call (Eq, [v1; v2]), typ))
| _ -> no_change
end
| "neq_bits", [AV_cval (v1, _); AV_cval (v2, _)] when ctyp_equal (cval_ctyp v1) (cval_ctyp v2) ->
begin match cval_ctyp v1 with
| CT_fbits _ | CT_sbits _ ->
AE_val (AV_cval (V_call (Neq, [v1; v2]), typ))
| _ -> no_change
end
| "eq_int", [AV_cval (v1, _); AV_cval (v2, _)] ->
AE_val (AV_cval (V_call (Eq, [v1; v2]), typ))
| "eq_bit", [AV_cval (v1, _); AV_cval (v2, _)] ->
AE_val (AV_cval (V_call (Eq, [v1; v2]), typ))
| "zeros", [_] ->
begin match destruct_vector ctx.tc_env typ with
| Some (Nexp_aux (Nexp_constant n, _), _, Typ_aux (Typ_id id, _))
when string_of_id id = "bit" && Big_int.less_equal n (Big_int.of_int 64) ->
let n = Big_int.to_int n in
AE_val (AV_cval (V_lit (VL_bits (Util.list_init n (fun _ -> Sail2_values.B0), true), CT_fbits (n, true)), typ))
| _ -> no_change
end
| "zero_extend", [AV_cval (v, _); _] ->
begin match destruct_vector ctx.tc_env typ with
| Some (Nexp_aux (Nexp_constant n, _), _, Typ_aux (Typ_id id, _))
when string_of_id id = "bit" && Big_int.less_equal n (Big_int.of_int 64) ->
AE_val (AV_cval (V_call (Zero_extend (Big_int.to_int n), [v]), typ))
| _ -> no_change
end
| "sign_extend", [AV_cval (v, _); _] ->
begin match destruct_vector ctx.tc_env typ with
| Some (Nexp_aux (Nexp_constant n, _), _, Typ_aux (Typ_id id, _))
when string_of_id id = "bit" && Big_int.less_equal n (Big_int.of_int 64) ->
AE_val (AV_cval (V_call (Sign_extend (Big_int.to_int n), [v]), typ))
| _ -> no_change
end
| "lteq", [AV_cval (v1, _); AV_cval (v2, _)] ->
AE_val (AV_cval (V_call (Ilteq, [v1; v2]), typ))
| "gteq", [AV_cval (v1, _); AV_cval (v2, _)] ->
AE_val (AV_cval (V_call (Igteq, [v1; v2]), typ))
| "lt", [AV_cval (v1, _); AV_cval (v2, _)] ->
AE_val (AV_cval (V_call (Ilt, [v1; v2]), typ))
| "gt", [AV_cval (v1, _); AV_cval (v2, _)] ->
AE_val (AV_cval (V_call (Igt, [v1; v2]), typ))
| "append", [AV_cval (v1, _); AV_cval (v2, _)] ->
begin match convert_typ ctx typ with
| CT_fbits _ | CT_sbits _ ->
AE_val (AV_cval (V_call (Concat, [v1; v2]), typ))
| _ -> no_change
end
| "not_bits", [AV_cval (v, _)] ->
AE_val (AV_cval (V_call (Bvnot, [v]), typ))
| "add_bits", [AV_cval (v1, _); AV_cval (v2, _)] when ctyp_equal (cval_ctyp v1) (cval_ctyp v2) ->
AE_val (AV_cval (V_call (Bvadd, [v1; v2]), typ))
| "sub_bits", [AV_cval (v1, _); AV_cval (v2, _)] when ctyp_equal (cval_ctyp v1) (cval_ctyp v2) ->
AE_val (AV_cval (V_call (Bvsub, [v1; v2]), typ))
| "and_bits", [AV_cval (v1, _); AV_cval (v2, _)] when ctyp_equal (cval_ctyp v1) (cval_ctyp v2) ->
AE_val (AV_cval (V_call (Bvand, [v1; v2]), typ))
| "or_bits", [AV_cval (v1, _); AV_cval (v2, _)] when ctyp_equal (cval_ctyp v1) (cval_ctyp v2) ->
AE_val (AV_cval (V_call (Bvor, [v1; v2]), typ))
| "xor_bits", [AV_cval (v1, _); AV_cval (v2, _)] when ctyp_equal (cval_ctyp v1) (cval_ctyp v2) ->
AE_val (AV_cval (V_call (Bvxor, [v1; v2]), typ))
| "vector_subrange", [AV_cval (vec, _); AV_cval (f, _); AV_cval (t, _)] ->
begin match convert_typ ctx typ with
| CT_fbits (n, true) ->
AE_val (AV_cval (V_call (Slice n, [vec; t]), typ))
| _ -> no_change
end
| "slice", [AV_cval (vec, _); AV_cval (start, _); AV_cval (len, _)] ->
begin match convert_typ ctx typ with
| CT_fbits (n, _) ->
AE_val (AV_cval (V_call (Slice n, [vec; start]), typ))
| CT_sbits (64, _) ->
AE_val (AV_cval (V_call (Sslice 64, [vec; start; len]), typ))
| _ -> no_change
end
| "vector_access", [AV_cval (vec, _); AV_cval (n, _)] ->
AE_val (AV_cval (V_call (Bvaccess, [vec; n]), typ))
| "add_int", [AV_cval (op1, _); AV_cval (op2, _)] ->
begin match destruct_range ctx.local_env typ with
| None -> no_change
| Some (kids, constr, n, m) ->
match nexp_simp n, nexp_simp m with
| Nexp_aux (Nexp_constant n, _), Nexp_aux (Nexp_constant m, _)
when Big_int.less_equal (min_int 64) n && Big_int.less_equal m (max_int 64) ->
AE_val (AV_cval (V_call (Iadd, [op1; op2]), typ))
| n, m when prove __POS__ ctx.local_env (nc_lteq (nconstant (min_int 64)) n) && prove __POS__ ctx.local_env (nc_lteq m (nconstant (max_int 64))) ->
AE_val (AV_cval (V_call (Iadd, [op1; op2]), typ))
| _ -> no_change
end
| "replicate_bits", [AV_cval (vec, vtyp); _] ->
begin match destruct_vector ctx.tc_env typ, destruct_vector ctx.tc_env vtyp with
| Some (Nexp_aux (Nexp_constant n, _), _, _), Some (Nexp_aux (Nexp_constant m, _), _, _)
when Big_int.less_equal n (Big_int.of_int 64) ->
let times = Big_int.div n m in
if Big_int.equal (Big_int.mul m times) n then
AE_val (AV_cval (V_call (Replicate (Big_int.to_int times), [vec]), typ))
else
no_change
| _, _ ->
no_change
end
| "undefined_bit", _ ->
AE_val (AV_cval (V_lit (VL_bit Sail2_values.B0, CT_bit), typ))
| "undefined_bool", _ ->
AE_val (AV_cval (V_lit (VL_bool false, CT_bool), typ))
| _, _ ->
no_change
let analyze_primop ctx id args typ =
let no_change = AE_app (id, args, typ) in
if !optimize_primops then
try analyze_primop' ctx id args typ with
| Failure str ->
no_change
else
no_change
let optimize_anf ctx aexp =
analyze_functions ctx analyze_primop (c_literals ctx aexp)
let unroll_loops = None
let specialize_calls = false
let ignore_64 = false
let struct_value = false
let use_real = false
let branch_coverage = Opts.branch_coverage
let track_throw = true
end
(** Functions that have heap-allocated return types are implemented by
passing a pointer a location where the return value should be
stored. The ANF -> Sail IR pass for expressions simply outputs an
I_return instruction for any return value, so this function walks
over the IR ast for expressions and modifies the return statements
into code that sets that pointer, as well as adds extra control
flow to cleanup heap-allocated variables correctly when a function
terminates early. See the generate_cleanup function for how this is
done. *)
let fix_early_heap_return ret ret_ctyp instrs =
let end_function_label = label "end_function_" in
let is_return_recur (I_aux (instr, _)) =
match instr with
| I_if _ | I_block _ | I_try_block _ | I_end _ | I_funcall _ | I_copy _ | I_undefined _ -> true
| _ -> false
in
let rec rewrite_return instrs =
match instr_split_at is_return_recur instrs with
| instrs, [] -> instrs
| before, I_aux (I_block instrs, _) :: after ->
before
@ [iblock (rewrite_return instrs)]
@ rewrite_return after
| before, I_aux (I_try_block instrs, (_, l)) :: after ->
before
@ [itry_block l (rewrite_return instrs)]
@ rewrite_return after
| before, I_aux (I_if (cval, then_instrs, else_instrs, ctyp), (_, l)) :: after ->
before
@ [iif l cval (rewrite_return then_instrs) (rewrite_return else_instrs) ctyp]
@ rewrite_return after
| before, I_aux (I_funcall (CL_id (Return _, ctyp), extern, fid, args), aux) :: after ->
before
@ [I_aux (I_funcall (CL_addr (CL_id (ret, CT_ref ctyp)), extern, fid, args), aux)]
@ rewrite_return after
| before, I_aux (I_copy (CL_id (Return _, ctyp), cval), aux) :: after ->
before
@ [I_aux (I_copy (CL_addr (CL_id (ret, CT_ref ctyp)), cval), aux)]
@ rewrite_return after
| before, I_aux ((I_end _ | I_undefined _), _) :: after ->
before
@ [igoto end_function_label]
@ rewrite_return after
| before, (I_aux ((I_copy _ | I_funcall _), _) as instr) :: after ->
before @ instr :: rewrite_return after
| _, _ -> assert false
in
rewrite_return instrs
@ [ilabel end_function_label]
(* This is like fix_early_heap_return, but for stack allocated returns. *)
let fix_early_stack_return ret ret_ctyp instrs =
let is_return_recur (I_aux (instr, _)) =
match instr with
| I_if _ | I_block _ | I_try_block _ | I_end _ | I_funcall _ | I_copy _ -> true
| _ -> false
in
let rec rewrite_return instrs =
match instr_split_at is_return_recur instrs with
| instrs, [] -> instrs
| before, I_aux (I_block instrs, _) :: after ->
before
@ [iblock (rewrite_return instrs)]
@ rewrite_return after
| before, I_aux (I_try_block instrs, (_, l)) :: after ->
before
@ [itry_block l (rewrite_return instrs)]
@ rewrite_return after
| before, I_aux (I_if (cval, then_instrs, else_instrs, ctyp), (_, l)) :: after ->
before
@ [iif l cval (rewrite_return then_instrs) (rewrite_return else_instrs) ctyp]
@ rewrite_return after
| before, I_aux (I_funcall (CL_id (Return _, ctyp), extern, fid, args), aux) :: after ->
before
@ [I_aux (I_funcall (CL_id (ret, ctyp), extern, fid, args), aux)]
@ rewrite_return after
| before, I_aux (I_copy (CL_id (Return _, ctyp), cval), aux) :: after ->
before
@ [I_aux (I_copy (CL_id (ret, ctyp), cval), aux)]
@ rewrite_return after
| before, I_aux (I_end _, _) :: after ->
before
@ [ireturn (V_id (ret, ret_ctyp))]
@ rewrite_return after
| before, (I_aux ((I_copy _ | I_funcall _), _) as instr) :: after ->
before @ instr :: rewrite_return after
| _, _ -> assert false
in
rewrite_return instrs
let rec insert_heap_returns ret_ctyps = function
| (CDEF_spec (id, _, _, ret_ctyp) as cdef) :: cdefs ->
cdef :: insert_heap_returns (Bindings.add id ret_ctyp ret_ctyps) cdefs
| CDEF_fundef (id, None, args, body) :: cdefs ->
let gs = gensym () in
begin match Bindings.find_opt id ret_ctyps with
| None ->
raise (Reporting.err_general (id_loc id) ("Cannot find return type for function " ^ string_of_id id))
| Some ret_ctyp when not (is_stack_ctyp ret_ctyp) ->
CDEF_fundef (id, Some gs, args, fix_early_heap_return (name gs) ret_ctyp body)
:: insert_heap_returns ret_ctyps cdefs
| Some ret_ctyp ->
CDEF_fundef (id, None, args, fix_early_stack_return (name gs) ret_ctyp (idecl (id_loc id) ret_ctyp (name gs) :: body))
:: insert_heap_returns ret_ctyps cdefs
end
| CDEF_fundef (id, gs, _, _) :: _ ->
raise (Reporting.err_unreachable (id_loc id) __POS__ "Found function with return already re-written in insert_heap_returns")
| cdef :: cdefs ->
cdef :: insert_heap_returns ret_ctyps cdefs
| [] -> []
(** To keep things neat we use GCC's local labels extension to limit
the scope of labels. We do this by iterating over all the blocks
and adding a __label__ declaration with all the labels local to
that block. The add_local_labels function is called by the code
generator just before it outputs C.
See https://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html **)
let add_local_labels' instrs =
let is_label (I_aux (instr, _)) =
match instr with
| I_label str -> [str]
| _ -> []
in
let labels = List.concat (List.map is_label instrs) in
let local_label_decl = iraw ("__label__ " ^ String.concat ", " labels ^ ";\n") in
if labels = [] then
instrs
else
local_label_decl :: instrs
let add_local_labels instrs =
match map_instrs add_local_labels' (iblock instrs) with
| I_aux (I_block instrs, _) -> instrs
| _ -> assert false
(**************************************************************************)
(* 5. Optimizations *)
(**************************************************************************)
let hoist_ctyp = function
| CT_lint | CT_lbits _ | CT_struct _ -> true
| _ -> false
let hoist_counter = ref 0
let hoist_id () =
let id = mk_id ("gh#" ^ string_of_int !hoist_counter) in
incr hoist_counter;
name id
let hoist_allocations recursive_functions = function
| CDEF_fundef (function_id, _, _, _) as cdef when IdSet.mem function_id recursive_functions ->
[cdef]
| CDEF_fundef (function_id, heap_return, args, body) ->
let decls = ref [] in
let cleanups = ref [] in
let rec hoist = function
| I_aux (I_decl (ctyp, decl_id), annot) :: instrs when hoist_ctyp ctyp ->
let hid = hoist_id () in
decls := idecl (snd annot) ctyp hid :: !decls;
cleanups := iclear ctyp hid :: !cleanups;
let instrs = instrs_rename decl_id hid instrs in
I_aux (I_reset (ctyp, hid), annot) :: hoist instrs
| I_aux (I_init (ctyp, decl_id, cval), annot) :: instrs when hoist_ctyp ctyp ->
let hid = hoist_id () in
decls := idecl (snd annot) ctyp hid :: !decls;
cleanups := iclear ctyp hid :: !cleanups;
let instrs = instrs_rename decl_id hid instrs in
I_aux (I_reinit (ctyp, hid, cval), annot) :: hoist instrs
| I_aux (I_clear (ctyp, _), _) :: instrs when hoist_ctyp ctyp ->
hoist instrs
| I_aux (I_block block, annot) :: instrs ->
I_aux (I_block (hoist block), annot) :: hoist instrs
| I_aux (I_try_block block, annot) :: instrs ->
I_aux (I_try_block (hoist block), annot) :: hoist instrs
| I_aux (I_if (cval, then_instrs, else_instrs, ctyp), annot) :: instrs ->
I_aux (I_if (cval, hoist then_instrs, hoist else_instrs, ctyp), annot) :: hoist instrs
| instr :: instrs -> instr :: hoist instrs
| [] -> []
in
let body = hoist body in
if !decls = [] then
[CDEF_fundef (function_id, heap_return, args, body)]
else
[CDEF_startup (function_id, List.rev !decls);
CDEF_fundef (function_id, heap_return, args, body);
CDEF_finish (function_id, !cleanups)]
| cdef -> [cdef]
(** Once we specialize variants, there may be additional type
dependencies which could be in the wrong order. As such we need to
sort the type definitions in the list of cdefs. *)
let sort_ctype_defs cdefs =
(* Split the cdefs into type definitions and non type definitions *)
let is_ctype_def = function CDEF_type _ -> true | _ -> false in
let unwrap = function CDEF_type ctdef -> ctdef | _ -> assert false in
let ctype_defs = List.map unwrap (List.filter is_ctype_def cdefs) in
let cdefs = List.filter (fun cdef -> not (is_ctype_def cdef)) cdefs in
let ctdef_id = function
| CTD_enum (id, _) | CTD_struct (id, _) | CTD_variant (id, _) -> id
in
let ctdef_ids = function
| CTD_enum _ -> IdSet.empty
| CTD_struct (_, ctors) | CTD_variant (_, ctors) ->
List.fold_left (fun ids (_, ctyp) -> IdSet.union (ctyp_ids ctyp) ids) IdSet.empty ctors
in
(* Create a reverse (i.e. from types to the types that are dependent
upon them) id graph of dependencies between types *)
let module IdGraph = Graph.Make(Id) in
let graph =
List.fold_left (fun g ctdef ->
List.fold_left (fun g id -> IdGraph.add_edge id (ctdef_id ctdef) g)
(IdGraph.add_edges (ctdef_id ctdef) [] g) (* Make sure even types with no dependencies are in graph *)
(IdSet.elements (ctdef_ids ctdef)))
IdGraph.empty
ctype_defs
in
(* Then select the ctypes in the correct order as given by the topsort *)
let ids = IdGraph.topsort graph in
let ctype_defs =
List.map (fun id -> CDEF_type (List.find (fun ctdef -> Id.compare (ctdef_id ctdef) id = 0) ctype_defs)) ids
in
ctype_defs @ cdefs
let removed = icomment "REMOVED"
let is_not_removed = function
| I_aux (I_comment "REMOVED", _) -> false
| _ -> true
(** This optimization looks for patterns of the form:
create x : t;
x = y;
// modifications to x, and no changes to y
y = x;
// no further changes to x
kill x;
If found, we can remove the variable x, and directly modify y instead. *)
let remove_alias =
let pattern ctyp id =
let alias = ref None in
let rec scan ctyp id n instrs =
match n, !alias, instrs with
| 0, None, I_aux (I_copy (CL_id (id', ctyp'), V_id (a, ctyp'')), _) :: instrs
when Name.compare id id' = 0 && ctyp_equal ctyp ctyp' && ctyp_equal ctyp' ctyp'' ->
alias := Some a;
scan ctyp id 1 instrs
| 1, Some a, I_aux (I_copy (CL_id (a', ctyp'), V_id (id', ctyp'')), _) :: instrs
when Name.compare a a' = 0 && Name.compare id id' = 0 && ctyp_equal ctyp ctyp' && ctyp_equal ctyp' ctyp'' ->
scan ctyp id 2 instrs
| 1, Some a, instr :: instrs ->
if NameSet.mem a (instr_ids instr) then
None
else
scan ctyp id 1 instrs
| 2, Some a, I_aux (I_clear (ctyp', id'), _) :: instrs
when Name.compare id id' = 0 && ctyp_equal ctyp ctyp' ->
scan ctyp id 2 instrs
| 2, Some a, instr :: instrs ->
if NameSet.mem id (instr_ids instr) then
None
else
scan ctyp id 2 instrs
| 2, Some a, [] -> !alias
| n, _, _ :: instrs when n = 0 || n > 2 -> scan ctyp id n instrs
| _, _, I_aux (_, (_, l)) :: instrs -> raise (Reporting.err_unreachable l __POS__ "optimize_alias")
| _, _, [] -> None
in
scan ctyp id 0
in
let remove_alias id alias = function
| I_aux (I_copy (CL_id (id', _), V_id (alias', _)), _)
when Name.compare id id' = 0 && Name.compare alias alias' = 0 -> removed
| I_aux (I_copy (CL_id (alias', _), V_id (id', _)), _)
when Name.compare id id' = 0 && Name.compare alias alias' = 0 -> removed
| I_aux (I_clear (_, id'), _) -> removed
| instr -> instr
in
let rec opt = function
| I_aux (I_decl (ctyp, id), _) as instr :: instrs ->
begin match pattern ctyp id instrs with
| None -> instr :: opt instrs
| Some alias ->
let instrs = List.map (map_instr (remove_alias id alias)) instrs in
filter_instrs is_not_removed (List.map (instr_rename id alias) instrs)
end
| I_aux (I_block block, aux) :: instrs -> I_aux (I_block (opt block), aux) :: opt instrs
| I_aux (I_try_block block, aux) :: instrs -> I_aux (I_try_block (opt block), aux) :: opt instrs
| I_aux (I_if (cval, then_instrs, else_instrs, ctyp), aux) :: instrs ->
I_aux (I_if (cval, opt then_instrs, opt else_instrs, ctyp), aux) :: opt instrs
| instr :: instrs ->
instr :: opt instrs
| [] -> []
in
function
| CDEF_fundef (function_id, heap_return, args, body) ->
[CDEF_fundef (function_id, heap_return, args, opt body)]
| cdef -> [cdef]
(** This optimization looks for patterns of the form
create x : t;
create y : t;
// modifications to y, no changes to x
x = y;
kill y;
If found we can replace y by x *)
let combine_variables =
let pattern ctyp id =
let combine = ref None in
let rec scan id n instrs =
match n, !combine, instrs with
| 0, None, I_aux (I_block block, _) :: instrs ->
begin match scan id 0 block with
| Some combine -> Some combine
| None -> scan id 0 instrs
end
| 0, None, I_aux (I_decl (ctyp', id'), _) :: instrs when ctyp_equal ctyp ctyp' ->
combine := Some id';
scan id 1 instrs
| 1, Some c, I_aux (I_copy (CL_id (id', ctyp'), V_id (c', ctyp'')), _) :: instrs
when Name.compare c c' = 0 && Name.compare id id' = 0 && ctyp_equal ctyp ctyp' && ctyp_equal ctyp' ctyp'' ->
scan id 2 instrs
(* Ignore seemingly early clears of x, as this can happen along exception paths *)
| 1, Some c, I_aux (I_clear (_, id'), _) :: instrs
when Name.compare id id' = 0 ->
scan id 1 instrs
| 1, Some c, instr :: instrs ->
if NameSet.mem id (instr_ids instr) then
None
else
scan id 1 instrs
| 2, Some c, I_aux (I_clear (ctyp', c'), _) :: instrs
when Name.compare c c' = 0 && ctyp_equal ctyp ctyp' ->
!combine
| 2, Some c, instr :: instrs ->
if NameSet.mem c (instr_ids instr) then
None
else
scan id 2 instrs
| 2, Some c, [] -> !combine
| n, _, _ :: instrs -> scan id n instrs
| _, _, [] -> None
in
scan id 0
in
let remove_variable id = function