[EXPERIMENT] Tail encode

[iglosiggio]

This PR encodes arc4 structs tail-first instead of head-first. This helps with code generation sometimes (because the required bytestrings are usually already in the stack).

This is a draft because opcount is not the only relevant metric. We should discuss contract size and see if there's an alternative approach via teal or mir peepholes.

[engineering-ci]

⚠️ No changelog fragment detected

[engineering-ci]

Name	Status	O0 bytes	O1 bytes	O2 bytes	O0 ops	O1 ops	O2 ops
arc_28	🟢	+8	-	-	+4	-	-
box_storage	🔺	-	+2🔺	+2	+3	+1🔺	+1
voting	🟢	-8	-7🟢	-7	-4	-4	-4
abi_routing/Reference	🟢	+4	-	-	+2	-	-
arc4_conversions/TestContract	🟢	-58	-18🟢	-18	-22	-16🟢	-16
arc4_dynamic_arrays	🟢	-55	-	-	-19	-	-
arc4_signature/ContractTwo	🟢	+2	-9🟢	-9	+1	-5🟢	-5
arc4_types/Arc4ArraysContract	🟢	+18	-	-	+12	-	-
arc4_types/Arc4BoolEvalContract	🟢	+6	-	-	+6	-	-
arc4_types/Arc4BoolTypeContract	🟢	-8	-	-	-2	-	-
arc4_types/Arc4DynamicBytesContract	🟢	+12	-	-	+8	-	-
arc4_types/Arc4DynamicStringArrayContract	🟢	+13	-	-	+10	-	-
arc4_types/Arc4MutableParamsContract	🟢	+4	-	-	+2	-	-
arc4_types/Arc4MutationContract	🟢	+213	-	-	+134	-	-
arc4_types/Arc4NumericTypesContract	🟢	-2	-	-	-1	-	-
arc4_types/Arc4StructsFromAnotherModule	🟢	-2	-	-	-1	-	-
arc4_types/Arc4StructsTypeContract	🟢	-6	-	-	-3	-	-
arc4_types/Arc4TuplesTypeContract	🟢	+12	-	-	+7	-	-
arc4_types/MutableParams2	🟢	+26	-	-	+19	-	-
arc_56	🟢	-2	-1🟢	-1	-1	-4🟢	-4
array/AbiCallContract	🟢	+2	-	-	+3	-	-
array/Contract	🤔	-46	+39🔺	+39	-22	-22	-21🟢
array/ImmutableArrayContract	🤔	-40	+8🔺	+8	+2	-7🟢	-7
array/ImmutableArrayInitContract	🟢	-8	-	-	+2	-	-
array/StaticSizeContract	🔺	-2	+7🔺	+7	+1	+13🔺	+13
avm_types_in_abi	🟢	-18	-6🟢	-6	-9	-4🟢	-4
group_side_effects/AppExpectingEffects	🟢	-2	-	-	-1	-	-
intrinsics/Optimizations	🟢	-8	-7🟢	-7	-4	-5🟢	-5
literals	🟢	+4	-	-	+2	-	-
marketplace_demo/DigitalMarketplaceWithImmStruct	🤔	-26	+52🔺	+52	-13	-7🟢	-7
marketplace_demo/DigitalMarketplaceWithStruct	🤔	-26	+52🔺	+52	-13	-7🟢	-7
marketplace_demo/DigitalMarketplaceWithTups	🤔	-2	+43🔺	+43	-1	-8🟢	-8
mutable_native_types/Case1WithTups	🔺	-16	+2🔺	+2	-7	+1🔺	+1
mutable_native_types/Case2WithImmStruct	🟢	-10	-3🟢	-3	-4	-2🟢	-2
mutable_native_types/Case3WithStruct	🟢	-6	-3🟢	-3	-2	-2	-2
mutable_native_types/Contract	🤔	-22	+3🔺	+3	-5	-6🟢	-6
mutable_native_types/TestAbiCall	🟢	-34	-4🟢	-4	-8	-2🟢	-2
named_tuples	🟢	-9	-5🟢	-5	-4	-3🟢	-3
regression_tests/Issue118	🟢	+4	-	-	+2	-	-
regression_tests/SlotAllocationInlining	🟢	-2	-	-	-1	-	-
regression_tests/VRFVerifier	🟢	-	-4🟢	-4	-	-3🟢	-3
state_mutations	🟢	+2	-	-	+5	-	-
struct_by_name	🟢	-18	-	-	-9	-	-
template_variables	🟢	-4	-	-	-2	-	-
tuple_support/NestedTuples	🟢	-99	-2🟢	-2	-45	-5🟢	-5
tuple_support/NestedTuplesStorage	🟢	+2	-8🟢	-8	+6	-4🟢	-4
typed_abi_call/Greeter	🟢	-18	-	-	-9	-	-
typed_abi_call/Logger	🟢	-6	-6	-6	-3	-13🟢	-13
Total	🤔	-231	+125🔺	+125	+16	-114🟢	-113🟢

[engineering-ci]

Coverage Report

File	Stmts	Miss	Cover	Missing
src/puya
__main__.py	36	6	83%	45, 52–53, 71–72, 78
arc32.py	89	4	96%	74, 125–130
arc56.py	81	4	95%	285–287, 297
artifact_sorter.py	57	2	96%	32, 89
compile.py	210	7	97%	98–99, 173–174, 182, 343, 401
context.py	52	1	98%	39
errors.py	41	1	98%	59
log.py	265	66	75%	82, 92–93, 98–105, 120–128, 150, 186–187, 229–231, 234–236, 238, 251–267, 296, 302, 312–317, 320, 388–389, 426–428, 441–455, 479
main.py	41	7	83%	31, 50–55
parse.py	83	4	95%	31, 40, 50, 56
program_refs.py	28	2	93%	45, 56
utils.py	226	14	94%	37, 196, 201–204, 222–224, 258, 265, 288, 290, 309, 348
src/puya/awst
function_traverser.py	330	3	99%	66, 76, 413
nodes.py	1311	63	95%	113, 117–120, 160, 164–167, 462, 527, 700, 769, 795, 853, 873, 896, 935, 980, 1009–1010, 1032, 1036, 1105, 1126, 1157–1158, 1185, 1188–1190, 1208, 1242, 1245, 1283, 1288, 1415, 1441, 1474, 1506, 1532, 1537, 1784, 1928, 1947, 2013, 2051, 2060, 2279, 2328, 2346, 2350, 2468, 2615, 2620, 2625, 2633, 2638, 2643, 2680–2681, 2691
serialize.py	76	12	84%	21–25, 49, 94–100, 117, 121
to_code_visitor.py	479	11	98%	149, 260, 297, 343, 380, 494–497, 677, 705, 709
txn_fields.py	101	1	99%	53
wtypes.py	376	9	98%	233, 314, 366, 379, 390, 395–396, 437, 466
src/puya/awst/validation
base_invoker.py	47	4	91%	55, 62, 72–76
immutable.py	33	2	94%	29, 37
inner_transactions.py	196	1	99%	168
labels.py	30	8	73%	25–27, 32, 36–41
src/puya/ir
_arc4_default_args.py	110	15	86%	63–64, 79, 92, 94, 96, 98, 100, 102, 108, 115, 136–137, 232, 239
contract_metadata.py	229	7	97%	56, 206–210, 308–314
arc4_router.py	259	5	98%	169, 233, 335, 353, 519
arc4_types.py	162	19	88%	26–27, 46, 50, 54, 58, 62, 70, 96, 103, 110, 117, 129, 135, 139, 151, 211, 215, 230
avm_ops.py	324	1	99%	46
avm_ops_models.py	37	2	95%	15, 23
context.py	113	6	95%	79, 91, 98, 101, 103, 112
encodings.py	204	6	97%	230, 233, 239, 257, 294, 298
main.py	224	14	94%	117, 126–132, 142–148, 174, 342–343, 355, 363
models.py	794	27	97%	211, 218, 413, 435, 496, 514, 518, 634–635, 759–760, 765, 771–775, 788, 845, 875, 931, 992, 1037, 1122, 1166, 1181, 1193, 1220, 1288–1289
mutating_register_context.py	87	3	97%	48–49, 51
op_utils.py	163	2	99%	212–219
ssa.py	151	2	99%	52–53
types.py	313	34	89%	56, 59, 62, 75, 80–82, 86–88, 128, 142, 181, 248, 251, 262, 271, 275, 278, 296, 302, 400–404, 506–507, 512, 529–530, 555, 561, 564, 567, 570
visitor.py	185	5	97%	184, 285, 306, 312, 358
visitor_mutator.py	223	7	97%	89–92, 94, 193, 234
src/puya/ir/builder
_utils.py	39	2	95%	50, 52
assignment.py	119	7	94%	63, 79, 190, 192–193, 220, 265
blocks.py	134	7	95%	55, 92–96, 158, 166, 231
bytes.py	70	14	80%	17–49, 138
callsub.py	109	10	91%	35–36, 57–60, 73, 118–122
dynamic_array.py	167	5	97%	81–82, 135–136, 172
encoding_validation.py	71	1	99%	121
flow_control.py	104	2	98%	53, 57
iteration.py	239	5	98%	103–104, 120, 152, 230
itxn.py	580	51	91%	154–155, 157, 171, 209–210, 234–235, 347–350, 643, 662–680, 711, 800, 824, 839, 846, 850, 886, 898, 902, 916, 928, 934, 940, 944, 964, 1028, 1038, 1042, 1046, 1062, 1074, 1102, 1108, 1112, 1116, 1120, 1138, 1149, 1160
main.py	747	49	93%	167, 292, 304–323, 333–335, 402, 426, 450, 474–475, 499, 525, 567, 572–573, 584–585, 753, 778–779, 811, 846, 927, 992, 1091–1095, 1178, 1246, 1249, 1402, 1428, 1456–1457, 1608, 1628, 1683–1685
sequence.py	136	6	96%	191–196, 217–220, 235–236
storage.py	208	5	98%	117, 335–339, 351
src/puya/ir/builder/aggregates
arc4_codecs.py	318	25	92%	58, 94, 147–148, 202, 269, 320, 333, 349, 392, 410, 426–428, 442–444, 518, 535, 537, 554–555, 570–571, 600
main.py	88	3	97%	76, 102, 116
sequence.py	156	1	99%	144
src/puya/ir/destructure
coalesce_locals.py	144	21	85%	198, 209, 213–224, 230–231, 246–251
critical_edges.py	32	1	97%	24
parcopy.py	72	1	99%	80
src/puya/ir/optimize
_call_graph.py	32	1	97%	42
add_box_extract_replace.py	279	5	98%	235–236, 240, 276, 516
assignments.py	114	4	96%	48, 168, 184–185
compiled_reference.py	101	5	95%	56, 87, 168–173
constant_propagation.py	71	1	99%	90
control_op_simplification.py	77	1	99%	170
inlining.py	244	11	95%	34–43, 47, 54, 417, 421, 425, 435, 439
inner_txn.py	36	2	94%	49–50
intrinsic_simplification.py	809	42	95%	268, 514, 545, 556–557, 625–626, 647, 752, 833, 864–893, 1244–1246, 1325, 1351, 1353, 1426, 1440, 1471, 1477, 1479, 1481, 1486, 1488, 1490, 1494, 1568
repeated_loads_elimination.py	155	2	99%	156, 173
src/puya/ir/validation
_base.py	30	1	97%	28
compile_reference_validator.py	20	2	90%	24, 30
min_avm_version_validator.py	15	4	73%	16–20
op_run_mode_validator.py	19	1	95%	29
slot_reservation.py	18	1	94%	20
src/puya/mir
aligned_writer.py	63	2	97%	21, 61
builder.py	207	23	89%	129–131, 159–161, 180, 183, 186, 189, 192, 195, 198, 254, 261, 401, 404, 407, 410, 413, 416, 419, 422
main.py	77	1	99%	37
models.py	499	4	99%	120, 255, 321, 727
output.py	61	1	98%	20
visitor.py	86	1	99%	175
src/puya/mir/stack_allocation
f_stack.py	95	3	97%	58–67
l_stack.py	117	1	99%	71
peephole.py	41	3	93%	38, 40, 43
x_stack.py	203	3	99%	33, 331–335
src/puya/teal
builder.py	200	2	99%	74, 114
models.py	470	1	99%	461
stack_manipulations.py	31	1	97%	42
src/puya/teal/optimize
constant_block.py	93	4	96%	43, 126, 163, 180
constant_stack_shuffling.py	94	9	90%	54–55, 77–78, 94–100
main.py	176	4	98%	141, 200, 227–228
peephole.py	137	2	99%	170, 295
repeated_rotations.py	51	5	90%	16, 52–55
repeated_rotations_search.py	90	6	93%	35, 41–42, 58, 68–69
src/puya/ussemble
assemble.py	201	3	99%	253, 273, 317
models.py	26	1	96%	16
op_spec_models.py	22	1	95%	20
src/puyapy
__main__.py	43	6	86%	155, 160–165, 204, 213
client_gen.py	110	11	90%	59–60, 78–82, 86, 200, 207–208, 228
compile.py	91	13	86%	41, 57, 68, 72, 132–133, 141–144, 153–156
find_sources.py	97	4	96%	25, 46, 105, 124
interpreter_data.py	18	2	89%	32–33
models.py	103	1	99%	76
parse.py	270	35	87%	115–120, 179, 189, 197, 209–210, 226–228, 239–244, 252–257, 261, 436, 440–441, 473–476, 480–481, 494–496, 501
template.py	32	8	75%	10–11, 18–19, 27–28, 34, 37
src/puyapy/awst_build
arc4_client.py	101	26	74%	45–49, 57, 69, 75, 79, 96, 108, 111–112, 118, 121, 124, 130, 133, 136–141, 144, 147, 150, 153, 156, 159, 162, 165
arc4_client_gen.py	134	8	94%	30, 89–90, 100, 102, 117–118, 188
arc4_decorators.py	246	51	79%	45, 90–91, 98–100, 111–115, 123–125, 146–148, 151, 179, 187, 201, 203, 236, 249–250, 264–265, 279–280, 287, 290–296, 301, 308, 329, 337, 341, 351–355, 371, 373, 376–377, 386, 389–390, 392
arc4_utils.py	115	4	97%	162, 169, 183, 211
base_mypy_visitor.py	155	28	82%	59, 69, 92–100, 167–173, 191, 199–212, 226, 228, 230, 281, 285, 289, 291, 298–318
context.py	271	61	77%	57, 60, 70–71, 89–90, 130, 176, 179–180, 182, 234, 239, 245–249, 256, 265, 267, 270–272, 274, 281, 283, 293–306, 318, 332, 335–347, 365, 383, 408, 417–423
contract.py	328	31	91%	123, 175, 204–208, 248, 250, 254, 258, 266, 278, 280, 350, 353, 365, 373, 376, 379, 382, 385, 388, 391, 394, 397, 490–494, 543–547, 621–625, 683, 709
intrinsic_factory.py	26	2	92%	67–69
intrinsic_models.py	49	1	98%	55
main.py	42	1	98%	41
module.py	428	61	86%	139, 159, 165–182, 199–200, 207, 216–217, 224–228, 250, 279, 299–300, 311, 333–336, 346–348, 354, 371–374, 387, 421, 450–451, 472–473, 529–530, 556, 567, 570, 576, 589, 595, 601, 621, 641, 646, 650, 659–663, 755, 763, 765
pytypes.py	636	63	90%	87, 97–99, 104, 111, 116–118, 122–124, 151–152, 192, 210–216, 239, 263, 305, 343–345, 374, 441, 450, 469, 487, 491, 606–607, 691–693, 707–708, 775–776, 880, 891–892, 930–931, 978–979, 984, 1053–1054, 1077–1078, 1229–1230, 1258, 1286, 1322–1324, 1364, 1374–1375
subroutine.py	640	42	93%	164, 184–185, 282, 308–309, 327, 344, 369, 377, 388, 421–424, 537–538, 593, 726, 737, 739, 748, 766, 769, 801, 807, 868, 876–879, 885, 936, 941, 944–950, 1041, 1061, 1217, 1257, 1283, 1299–1300, 1309
utils.py	203	28	86%	30, 47–51, 79–80, 102, 141–142, 144, 188–189, 240, 248, 253, 266–270, 275–278, 285, 329–332
src/puyapy/awst_build/eb
_base.py	127	16	87%	52, 57–59, 64, 71, 80–82, 143, 154, 184, 189, 199, 210, 224–226
_bytes_backed.py	48	2	96%	30–31
_expect.py	122	17	86%	25, 36, 85–88, 107, 160–161, 219–222, 232–235
_literals.py	156	34	78%	44, 65, 77, 96, 125, 142, 156–160, 164, 168–174, 184–198, 203
_type_registry.py	41	3	93%	271–272, 285
utils.py	62	3	95%	36–38, 108
biguint.py	101	6	94%	56, 100, 139, 155–156, 158
binary_bool_op.py	105	3	97%	153, 161, 171
bool.py	55	9	84%	38–42, 58, 69, 82, 96
bytes.py	173	16	91%	102–103, 130–131, 136–137, 143–144, 147, 155, 233, 271, 292–293, 313–314
compiled.py	70	9	87%	85–89, 126–130, 153
conditional_literal.py	133	34	74%	97, 101, 161, 165–168, 177–179, 202–205, 214, 218, 222–225, 240–252, 261–262, 273–276
contracts.py	77	8	90%	55, 61, 63, 73, 99, 109, 111, 116
dict.py	27	5	81%	24, 32–34, 38
ensure_budget.py	31	1	97%	46
fixed_bytes.py	274	11	96%	110–111, 142, 250, 335, 412, 464, 516, 522, 586–587
interface.py	91	2	98%	317–319
intrinsics.py	120	8	93%	55–56, 70, 91, 98, 111, 118, 210
log.py	43	4	91%	45–46, 51, 60
logicsig.py	15	1	93%	25
none.py	27	4	85%	17, 27–28, 37
size_of.py	25	3	88%	31–33
string.py	144	13	91%	71, 115–116, 135, 140, 183, 190, 194, 206, 280–282, 302
subroutine.py	80	16	80%	46, 50–53, 68, 71–78, 93, 101–102, 104–107, 112
template_variables.py	37	2	95%	29, 57
tuple.py	338	12	96%	87, 94, 135, 154, 257, 350–351, 470, 546, 557–558, 621
uint64.py	108	5	95%	57, 118–119, 167–168
uint64_enums.py	40	2	95%	40, 45
unsigned_builtins.py	155	22	86%	73, 80, 104, 128, 132, 136, 140, 148, 152, 156, 160, 164, 174, 178, 184, 195, 201, 207, 246, 278, 290, 302
src/puyapy/awst_build/eb/arc4
_base.py	105	5	95%	183–186, 197, 227–228
_utils.py	123	5	96%	44, 103, 134, 197, 201
abi_call.py	349	21	94%	123, 129, 150, 220, 233–234, 316, 327, 407, 431, 464, 483–484, 503, 538, 582, 618, 685, 770–771, 788
address.py	73	2	97%	56, 115
bool.py	60	1	98%	42
dynamic_array.py	122	9	93%	109–110, 128, 152, 206, 221–222, 225–228
dynamic_bytes.py	68	3	96%	98–100
emit.py	53	2	96%	40–43
string.py	100	7	93%	54–55, 105, 126, 131–134
struct.py	82	1	99%	54
tuple.py	92	12	87%	51–53, 91–94, 97–98, 137–140, 145, 170
ufixed.py	74	2	97%	51, 110
uint.py	96	2	98%	101–106
src/puyapy/awst_build/eb/reference_types
account.py	82	1	99%	179
application.py	45	1	98%	39
asset.py	65	1	98%	47
src/puyapy/awst_build/eb/storage
_storage.py	108	20	81%	58, 66, 70, 74, 78, 82, 86, 90, 94, 104, 108, 112, 116, 122, 133, 139, 145, 157–159
_value_proxy.py	55	3	95%	42, 50, 54
box.py	113	1	99%	174
box_map.py	164	2	99%	199, 265
box_ref.py	111	17	85%	76–80, 89–93, 103, 111, 127, 135, 148, 153–162
global_state.py	127	6	95%	103–104, 113–114, 163–164
local_state.py	137	11	92%	98–99, 103, 150, 154, 158, 168, 172, 196, 253, 277
src/puyapy/awst_build/eb/transaction
base.py	39	2	95%	22, 42
group.py	51	1	98%	47
inner.py	54	2	96%	96–97
inner_params.py	88	5	94%	65, 77, 81, 169, 171
itxn_args.py	60	1	98%	72
src/puyapy/lsp
__main__.py	17	17	0%	1–44
analyse.py	268	191	29%	58–70, 76–183, 186–197, 201–216, 226–246, 249, 252–254, 265–281, 288–332, 349–373, 381, 385–386, 395–399, 404–411, 434–449, 461, 465, 467, 473, 482–487, 491
log.py	44	44	0%	1–89
server.py	133	82	38%	62–70, 74–79, 86–136, 153–155, 158–162, 165–172, 179–197, 200, 203–208, 218–220
src/puyapy/validation
arc4_copy.py	130	2	98%	35, 39
TOTAL	30164	2007	93%

Tests	Skipped	Failures	Errors	Time
1226	3 💤	0 ❌	0 🔥	8m 1s ⏱️