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
use rkyv::{Archive, Deserialize as RkyvDeserialize, Serialize as RkyvSerialize};
#[cfg(feature = "enable-serde")]
use serde::{Deserialize, Serialize};
#[cfg(feature = "detect-wasm-features")]
use wasmparser::{Parser, Payload, Validator, WasmFeatures};
/// Controls which experimental features will be enabled.
/// Features usually have a corresponding [WebAssembly proposal].
///
/// [WebAssembly proposal]: https://github.com/WebAssembly/proposals
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
#[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "artifact-size", derive(loupe::MemoryUsage))]
#[derive(RkyvSerialize, RkyvDeserialize, Archive)]
#[rkyv(derive(Debug), compare(PartialEq))]
pub struct Features {
/// Threads proposal should be enabled
pub threads: bool,
/// Reference Types proposal should be enabled
pub reference_types: bool,
/// SIMD proposal should be enabled
pub simd: bool,
/// Bulk Memory proposal should be enabled
pub bulk_memory: bool,
/// Multi Value proposal should be enabled
pub multi_value: bool,
/// Tail call proposal should be enabled
pub tail_call: bool,
/// Module Linking proposal should be enabled
pub module_linking: bool,
/// Multi Memory proposal should be enabled
pub multi_memory: bool,
/// 64-bit Memory proposal should be enabled
pub memory64: bool,
/// Wasm exceptions proposal should be enabled
pub exceptions: bool,
/// Relaxed SIMD proposal should be enabled
pub relaxed_simd: bool,
/// Extended constant expressions proposal should be enabled
pub extended_const: bool,
/// Wide Arithmetic proposal should be enabled
pub wide_arithmetic: bool,
}
impl Features {
/// Create a new feature
pub fn new() -> Self {
Self {
threads: true,
// Reference types should be on by default
reference_types: true,
// SIMD should be on by default
simd: true,
// Bulk Memory should be on by default
bulk_memory: true,
// Multivalue should be on by default
multi_value: true,
tail_call: false,
module_linking: false,
multi_memory: false,
memory64: false,
exceptions: false,
relaxed_simd: false,
wide_arithmetic: false,
// Extended Constant Expressions should be on by default
extended_const: true,
}
}
/// Create a new feature set with all features enabled.
pub fn all() -> Self {
Self {
threads: true,
reference_types: true,
simd: true,
bulk_memory: true,
multi_value: true,
tail_call: true,
module_linking: true,
multi_memory: true,
memory64: true,
exceptions: true,
relaxed_simd: true,
extended_const: true,
wide_arithmetic: true,
}
}
/// Create a new feature set with all features disabled.
pub fn none() -> Self {
Self {
threads: false,
reference_types: false,
simd: false,
bulk_memory: false,
multi_value: false,
tail_call: false,
module_linking: false,
multi_memory: false,
memory64: false,
exceptions: false,
relaxed_simd: false,
extended_const: false,
wide_arithmetic: false,
}
}
/// Configures whether the WebAssembly threads proposal will be enabled.
///
/// The [WebAssembly threads proposal][threads] is not currently fully
/// standardized and is undergoing development. Support for this feature can
/// be enabled through this method for appropriate WebAssembly modules.
///
/// This feature gates items such as shared memories and atomic
/// instructions.
///
/// This is `true` by default.
///
/// [threads]: https://github.com/webassembly/threads
pub fn threads(&mut self, enable: bool) -> &mut Self {
self.threads = enable;
self
}
/// Configures whether the WebAssembly reference types proposal will be
/// enabled.
///
/// The [WebAssembly reference types proposal][proposal] is now
/// fully standardized and enabled by default.
///
/// This feature gates items such as the `externref` type and multiple tables
/// being in a module. Note that enabling the reference types feature will
/// also enable the bulk memory feature.
///
/// This is `true` by default.
///
/// [proposal]: https://github.com/webassembly/reference-types
pub fn reference_types(&mut self, enable: bool) -> &mut Self {
self.reference_types = enable;
// The reference types proposal depends on the bulk memory proposal
if enable {
self.bulk_memory(true);
}
self
}
/// Configures whether the WebAssembly SIMD proposal will be
/// enabled.
///
/// The [WebAssembly SIMD proposal][proposal] is now
/// fully standardized.
/// Support for this feature can be enabled through this method
/// for appropriate WebAssembly modules.
///
/// This feature gates items such as the `v128` type and all of its
/// operators being in a module.
///
/// This is `true` by default.
///
/// [proposal]: https://github.com/webassembly/simd
pub fn simd(&mut self, enable: bool) -> &mut Self {
self.simd = enable;
self
}
/// Configures whether the WebAssembly Relaxed SIMD proposal will be
/// enabled.
///
/// The [WebAssembly Relaxed SIMD proposal][proposal] is now
/// fully standardized.
/// Support for this feature can be enabled through this method
/// for appropriate WebAssembly modules.
///
/// This is `false` by default.
///
/// [proposal]: https://github.com/WebAssembly/relaxed-simd
pub fn relaxed_simd(&mut self, enable: bool) -> &mut Self {
self.relaxed_simd = enable;
self
}
/// Configures whether the WebAssembly bulk memory operations proposal will
/// be enabled.
///
/// The [WebAssembly bulk memory operations proposal][proposal] is now
/// fully standardized and enabled by default.
///
/// This feature gates items such as the `memory.copy` instruction, passive
/// data/table segments, etc, being in a module.
///
/// This is `true` by default.
///
/// [proposal]: https://github.com/webassembly/bulk-memory-operations
pub fn bulk_memory(&mut self, enable: bool) -> &mut Self {
self.bulk_memory = enable;
// In case is false, we disable both threads and reference types
// since they both depend on bulk memory
if !enable {
self.reference_types(false);
}
self
}
/// Configures whether the WebAssembly multi-value proposal will
/// be enabled.
///
/// The [WebAssembly multi-value proposal][proposal] is now fully
/// standardized and enabled by default.
///
/// This feature gates functions and blocks returning multiple values in a
/// module, for example.
///
/// This is `true` by default.
///
/// [proposal]: https://github.com/webassembly/multi-value
pub fn multi_value(&mut self, enable: bool) -> &mut Self {
self.multi_value = enable;
self
}
/// Configures whether the WebAssembly tail-call proposal will
/// be enabled.
///
/// The [WebAssembly tail-call proposal][proposal] is now
/// fully standardized.
/// Support for this feature can be enabled through this method
/// for appropriate WebAssembly modules.
///
/// This feature gates tail-call functions in WebAssembly.
///
/// This is `false` by default.
///
/// [proposal]: https://github.com/webassembly/tail-call
pub fn tail_call(&mut self, enable: bool) -> &mut Self {
self.tail_call = enable;
self
}
/// Configures whether the WebAssembly module linking proposal will
/// be enabled.
///
/// The [WebAssembly module linking proposal][proposal] is not
/// currently fully standardized and is undergoing development.
/// Support for this feature can be enabled through this method for
/// appropriate WebAssembly modules.
///
/// This feature allows WebAssembly modules to define, import and
/// export modules and instances.
///
/// This is `false` by default.
///
/// [proposal]: https://github.com/webassembly/module-linking
pub fn module_linking(&mut self, enable: bool) -> &mut Self {
self.module_linking = enable;
self
}
/// Configures whether the WebAssembly multi-memory proposal will
/// be enabled.
///
/// The [WebAssembly multi-memory proposal][proposal] is now
/// fully standardized.
/// Support for this feature can be enabled through this method
/// for appropriate WebAssembly modules.
///
/// This feature adds the ability to use multiple memories within a
/// single Wasm module.
///
/// This is `false` by default.
///
/// [proposal]: https://github.com/WebAssembly/multi-memory
pub fn multi_memory(&mut self, enable: bool) -> &mut Self {
self.multi_memory = enable;
self
}
/// Configures whether the WebAssembly 64-bit memory proposal will
/// be enabled.
///
/// The [WebAssembly 64-bit memory proposal][proposal] is now
/// fully standardized.
/// Support for this feature can be enabled through this method
/// for appropriate WebAssembly modules.
///
/// This feature gates support for linear memory of sizes larger than
/// 2^32 bits.
///
/// This is `false` by default.
///
/// [proposal]: https://github.com/WebAssembly/memory64
pub fn memory64(&mut self, enable: bool) -> &mut Self {
self.memory64 = enable;
self
}
/// Configures whether the WebAssembly exception-handling proposal will be enabled.
///
/// The [WebAssembly exception-handling proposal][eh] is now
/// fully standardized.
/// Support for this feature can be enabled through this method
/// for appropriate WebAssembly modules.
///
/// This is `false` by default.
///
/// [eh]: https://github.com/webassembly/exception-handling
pub fn exceptions(&mut self, enable: bool) -> &mut Self {
self.exceptions = enable;
self
}
/// Configures whether the WebAssembly wide arithmetic proposal will be enabled.
///
/// The [Wide Arithmetic][wa] is not currently fully
/// standardized and is undergoing development. Support for this feature can
/// be enabled through this method for appropriate WebAssembly modules.
///
/// This is `false` by default.
///
/// [wa]: https://github.com/WebAssembly/wide-arithmetic
pub fn wide_arithmetic(&mut self, enable: bool) -> &mut Self {
self.wide_arithmetic = enable;
self
}
/// Configures whether the WebAssembly Extended Constant Expressions proposal will be enabled.
///
/// The [WebAssembly Extended Constant Expressions][extended-const] is now
/// fully standardized.
/// Support for this feature can be enabled through this method
/// for appropriate WebAssembly modules.
///
/// This is `true` by default.
///
/// [extended-const]: https://github.com/WebAssembly/extended-const
pub fn extended_const(&mut self, enable: bool) -> &mut Self {
self.extended_const = enable;
self
}
/// Checks if this features set contains all the features required by another set
pub fn contains_features(&self, required: &Self) -> bool {
// Check all required features
(!required.simd || self.simd)
&& (!required.bulk_memory || self.bulk_memory)
&& (!required.reference_types || self.reference_types)
&& (!required.threads || self.threads)
&& (!required.multi_value || self.multi_value)
&& (!required.exceptions || self.exceptions)
&& (!required.tail_call || self.tail_call)
&& (!required.module_linking || self.module_linking)
&& (!required.multi_memory || self.multi_memory)
&& (!required.memory64 || self.memory64)
&& (!required.relaxed_simd || self.relaxed_simd)
&& (!required.extended_const || self.extended_const)
&& (!required.wide_arithmetic || self.wide_arithmetic)
}
#[cfg(feature = "detect-wasm-features")]
/// Detects required WebAssembly features from a module binary.
///
/// This method analyzes a WebAssembly module's binary to determine which
/// features it requires. It does this by:
/// 1. Attempting to validate the module with different feature sets
/// 2. Analyzing validation errors to detect required features
/// 3. Parsing the module to detect certain common patterns
///
/// # Arguments
///
/// * `wasm_bytes` - The binary content of the WebAssembly module
///
/// # Returns
///
/// A new `Features` instance with the detected features enabled.
pub fn detect_from_wasm(wasm_bytes: &[u8]) -> Result<Self, wasmparser::BinaryReaderError> {
let mut features = Self::default();
// Simple test for exceptions - try to validate with exceptions disabled
let mut exceptions_test = WasmFeatures::default();
// Enable most features except exceptions
exceptions_test.set(WasmFeatures::BULK_MEMORY, true);
exceptions_test.set(WasmFeatures::REFERENCE_TYPES, true);
exceptions_test.set(WasmFeatures::SIMD, true);
exceptions_test.set(WasmFeatures::MULTI_VALUE, true);
exceptions_test.set(WasmFeatures::THREADS, true);
exceptions_test.set(WasmFeatures::TAIL_CALL, true);
exceptions_test.set(WasmFeatures::MULTI_MEMORY, true);
exceptions_test.set(WasmFeatures::MEMORY64, true);
exceptions_test.set(WasmFeatures::EXCEPTIONS, false);
let mut validator = Validator::new_with_features(exceptions_test);
if let Err(e) = validator.validate_all(wasm_bytes) {
let err_msg = e.to_string();
if err_msg.contains("exception") {
features.exceptions(true);
}
}
// Now try with all features enabled to catch anything we might have missed
let mut wasm_features = WasmFeatures::default();
wasm_features.set(WasmFeatures::EXCEPTIONS, true);
wasm_features.set(WasmFeatures::BULK_MEMORY, true);
wasm_features.set(WasmFeatures::REFERENCE_TYPES, true);
wasm_features.set(WasmFeatures::SIMD, true);
wasm_features.set(WasmFeatures::MULTI_VALUE, true);
wasm_features.set(WasmFeatures::THREADS, true);
wasm_features.set(WasmFeatures::TAIL_CALL, true);
wasm_features.set(WasmFeatures::MULTI_MEMORY, true);
wasm_features.set(WasmFeatures::MEMORY64, true);
wasm_features.set(WasmFeatures::RELAXED_SIMD, false);
let mut validator = Validator::new_with_features(wasm_features);
match validator.validate_all(wasm_bytes) {
Err(e) => {
// If validation fails due to missing feature support, check which feature it is
let err_msg = e.to_string().to_lowercase();
if err_msg.contains("exception") || err_msg.contains("try/catch") {
features.exceptions(true);
}
if err_msg.contains("bulk memory") {
features.bulk_memory(true);
}
if err_msg.contains("reference type") {
features.reference_types(true);
}
if err_msg.contains("relaxed simd") {
features.relaxed_simd(true);
} else if err_msg.contains("simd") {
features.simd(true);
}
if err_msg.contains("multi value") || err_msg.contains("multiple values") {
features.multi_value(true);
}
if err_msg.contains("thread") || err_msg.contains("shared memory") {
features.threads(true);
}
if err_msg.contains("tail call") {
features.tail_call(true);
}
if err_msg.contains("module linking") {
features.module_linking(true);
}
if err_msg.contains("multi memory") {
features.multi_memory(true);
}
if err_msg.contains("memory64") {
features.memory64(true);
}
if err_msg.contains("wide arithmetic") {
features.wide_arithmetic(true);
}
if err_msg.contains("constant expression") {
features.extended_const(true);
}
}
Ok(_) => {
// The module validated successfully with all features enabled,
// which means it could potentially use any of them.
// We'll do a more detailed analysis by parsing the module.
}
}
// A simple pass to detect certain common patterns
for payload in Parser::new(0).parse_all(wasm_bytes) {
let payload = payload?;
if let Payload::CustomSection(section) = payload {
let name = section.name();
// Exception handling has a custom section
if name.contains("exception") {
features.exceptions(true);
}
}
}
Ok(features)
}
/// Extend this feature set with another set.
///
/// Self will be modified to include all features that are required by
/// either set.
pub fn extend(&mut self, other: &Self) {
// Written this way to cause compile errors when new features are added.
let Self {
threads,
reference_types,
simd,
bulk_memory,
multi_value,
tail_call,
module_linking,
multi_memory,
memory64,
exceptions,
relaxed_simd,
extended_const,
wide_arithmetic,
} = other.clone();
*self = Self {
threads: self.threads || threads,
reference_types: self.reference_types || reference_types,
simd: self.simd || simd,
bulk_memory: self.bulk_memory || bulk_memory,
multi_value: self.multi_value || multi_value,
tail_call: self.tail_call || tail_call,
module_linking: self.module_linking || module_linking,
multi_memory: self.multi_memory || multi_memory,
memory64: self.memory64 || memory64,
exceptions: self.exceptions || exceptions,
relaxed_simd: self.relaxed_simd || relaxed_simd,
extended_const: self.extended_const || extended_const,
wide_arithmetic: self.wide_arithmetic || wide_arithmetic,
};
}
}
impl Default for Features {
fn default() -> Self {
Self::new()
}
}
#[cfg(test)]
mod test_features {
use super::*;
#[test]
fn default_features() {
let default = Features::default();
assert_eq!(
default,
Features {
threads: true,
reference_types: true,
simd: true,
bulk_memory: true,
multi_value: true,
tail_call: false,
module_linking: false,
multi_memory: false,
memory64: false,
exceptions: false,
relaxed_simd: false,
extended_const: true,
wide_arithmetic: false
}
);
}
#[test]
fn features_extend() {
let all = Features::all();
let mut target = Features::none();
target.extend(&all);
assert_eq!(target, all);
}
#[test]
fn enable_threads() {
let mut features = Features::new();
features.bulk_memory(false).threads(true);
assert!(features.threads);
}
#[test]
fn enable_reference_types() {
let mut features = Features::new();
features.bulk_memory(false).reference_types(true);
assert!(features.reference_types);
assert!(features.bulk_memory);
}
#[test]
fn enable_simd() {
let mut features = Features::new();
features.simd(true);
assert!(features.simd);
}
#[test]
fn enable_multi_value() {
let mut features = Features::new();
features.multi_value(true);
assert!(features.multi_value);
}
#[test]
fn enable_bulk_memory() {
let mut features = Features::new();
features.bulk_memory(true);
assert!(features.bulk_memory);
}
#[test]
fn disable_bulk_memory() {
let mut features = Features::new();
features
.threads(true)
.reference_types(true)
.bulk_memory(false);
assert!(!features.bulk_memory);
assert!(!features.reference_types);
}
#[test]
fn enable_tail_call() {
let mut features = Features::new();
features.tail_call(true);
assert!(features.tail_call);
}
#[test]
fn enable_module_linking() {
let mut features = Features::new();
features.module_linking(true);
assert!(features.module_linking);
}
#[test]
fn enable_multi_memory() {
let mut features = Features::new();
features.multi_memory(true);
assert!(features.multi_memory);
}
#[test]
fn enable_memory64() {
let mut features = Features::new();
features.memory64(true);
assert!(features.memory64);
}
}