numcodecs_wasm_host_reproducible/transform/
nan.rs

1use std::collections::VecDeque;
2
3use anyhow::{anyhow, Error};
4use wasm_encoder::reencode::{self, Reencode};
5
6/// Adapted from cranelift's NaN canonicalisation codegen pass
7/// <https://github.com/bytecodealliance/wasmtime/blob/ead6c7cc5dbb876437acbdf429a9190f25b96755/cranelift/codegen/src/nan_canonicalization.rs>
8/// Released under the Apache-2.0 WITH LLVM-exception License
9///
10/// Implementation written referencing:
11/// - WebAssembly Core Specification v2 <https://www.w3.org/TR/2024/WD-wasm-core-2-20240219>
12/// - The "WebAssembly 128-bit packed SIMD Extension" Specification: <https://github.com/WebAssembly/spec/blob/f8114686035f6ffc358771c822ede3c96bf54cd9/proposals/simd/SIMD.md>
13/// - The "Non-trapping Float-to-int Conversions" Extension Specification: <https://github.com/WebAssembly/spec/blob/f8114686035f6ffc358771c822ede3c96bf54cd9/proposals/nontrapping-float-to-int-conversion/Overview.md>
14pub enum NaNCanonicaliser {}
15
16impl NaNCanonicaliser {
17    pub fn apply_to_module(
18        wasm: &[u8],
19        features: wasmparser::WasmFeatures,
20    ) -> Result<Vec<u8>, anyhow::Error> {
21        let mut parser = wasmparser::Parser::new(0);
22        parser.set_features(features);
23
24        let mut module = wasm_encoder::Module::new();
25
26        let mut reencoder = NaNCanonicaliserReencoder {
27            func_type_num_params: Vec::new(),
28            function_type_indices: VecDeque::new(),
29        };
30        reencoder
31            .parse_core_module(&mut module, parser, wasm)
32            .map_err(|err| anyhow::format_err!("{}", err))?;
33
34        let wasm = module.finish();
35        wasmparser::Validator::new_with_features(features).validate_all(&wasm)?;
36        Ok(wasm)
37    }
38}
39
40struct NaNCanonicaliserReencoder {
41    func_type_num_params: Vec<u32>,
42    function_type_indices: VecDeque<usize>,
43}
44
45impl wasm_encoder::reencode::Reencode for NaNCanonicaliserReencoder {
46    type Error = Error;
47
48    fn parse_type_section(
49        &mut self,
50        types: &mut wasm_encoder::TypeSection,
51        section: wasmparser::TypeSectionReader<'_>,
52    ) -> Result<(), reencode::Error<Self::Error>> {
53        for func_ty in section.into_iter_err_on_gc_types() {
54            let func_ty = self.func_type(func_ty?)?;
55            #[expect(clippy::cast_possible_truncation)] // guaranteed by wasm spec
56            let num_params = func_ty.params().len() as u32;
57            self.func_type_num_params.push(num_params);
58            types.ty().func_type(&func_ty);
59        }
60        Ok(())
61    }
62
63    fn parse_function_section(
64        &mut self,
65        functions: &mut wasm_encoder::FunctionSection,
66        section: wasmparser::FunctionSectionReader<'_>,
67    ) -> Result<(), reencode::Error<Self::Error>> {
68        for function in section {
69            let function = self.type_index(function?);
70            self.function_type_indices.push_back(function as usize);
71            functions.function(function);
72        }
73        Ok(())
74    }
75
76    fn parse_function_body(
77        &mut self,
78        code: &mut wasm_encoder::CodeSection,
79        func: wasmparser::FunctionBody<'_>,
80    ) -> Result<(), reencode::Error<Self::Error>> {
81        let Some(function_ty) = self.function_type_indices.pop_front() else {
82            return Err(reencode::Error::UserError(anyhow!(
83                "wasm function body without declaration",
84            )));
85        };
86        let Some(num_params) = self.func_type_num_params.get(function_ty).copied() else {
87            return Err(reencode::Error::UserError(anyhow!(
88                "invalid type index for wasm function",
89            )));
90        };
91
92        let locals = func.get_locals_reader()?;
93        let locals = locals.into_iter().collect::<Result<Vec<_>, _>>()?;
94        let mut locals = locals
95            .into_iter()
96            .map(|(count, ty)| self.val_type(ty).map(|ty| (count, ty)))
97            .collect::<Result<Vec<_>, _>>()?;
98        let mut num_locals = locals.iter().map(|(count, _ty)| *count).sum::<u32>();
99
100        let mut stash_f32 = None;
101        let mut stash_f64 = None;
102        let mut stash_v128 = None;
103
104        let instructions = func.get_operators_reader()?;
105        for instruction in instructions {
106            if let Some(kind) = Self::may_produce_non_deterministic_nan(&instruction?)
107                .map_err(|err| reencode::Error::UserError(anyhow!(err)))?
108            {
109                match kind {
110                    MaybeNaNKind::F32 => stash_f32.get_or_insert_with(|| {
111                        let stash_f32 = num_params + num_locals;
112                        locals.push((1, wasm_encoder::ValType::F32));
113                        num_locals += 1;
114                        stash_f32
115                    }),
116                    MaybeNaNKind::F64 => stash_f64.get_or_insert_with(|| {
117                        let stash_f64 = num_params + num_locals;
118                        locals.push((1, wasm_encoder::ValType::F64));
119                        num_locals += 1;
120                        stash_f64
121                    }),
122                    MaybeNaNKind::F32x4 | MaybeNaNKind::F64x2 => {
123                        stash_v128.get_or_insert_with(|| {
124                            let stash_v128 = num_params + num_locals;
125                            locals.push((1, wasm_encoder::ValType::V128));
126                            num_locals += 1;
127                            stash_v128
128                        })
129                    }
130                };
131            }
132        }
133
134        let mut function = wasm_encoder::Function::new(locals);
135
136        for instruction in func.get_operators_reader()? {
137            let instruction = instruction?;
138
139            let kind = Self::may_produce_non_deterministic_nan(&instruction)
140                .map_err(|err| reencode::Error::UserError(anyhow!(err)))?;
141
142            function.instruction(&self.instruction(instruction)?);
143
144            if let Some(kind) = kind {
145                let Some(stash) = (match kind {
146                    MaybeNaNKind::F32 => stash_f32,
147                    MaybeNaNKind::F64 => stash_f64,
148                    MaybeNaNKind::F32x4 | MaybeNaNKind::F64x2 => stash_v128,
149                }) else {
150                    return Err(reencode::Error::UserError(anyhow!(
151                        "wasm float operation without matching canonicalisation stash",
152                    )));
153                };
154
155                for canon_instruction in
156                    Self::generate_nan_canonicalisation_instructions(kind, stash)
157                {
158                    function.instruction(&canon_instruction);
159                }
160            }
161        }
162
163        code.function(&function);
164
165        Ok(())
166    }
167}
168
169impl NaNCanonicaliserReencoder {
170    // Canonical 32-bit and 64-bit NaN values
171    const CANON_NAN_B32: u32 = 0x7FC0_0000;
172    const CANON_NAN_B32X4: u128 = 0x7FC0_0000_7FC0_0000_7FC0_0000_7FC0_0000;
173    const CANON_NAN_B64: u64 = 0x7FF8_0000_0000_0000;
174    const CANON_NAN_B64X2: u128 = 0x7FF8_0000_0000_0000_7FF8_0000_0000_0000;
175
176    fn generate_nan_canonicalisation_instructions(
177        kind: MaybeNaNKind,
178        stash: u32,
179    ) -> impl IntoIterator<Item = wasm_encoder::Instruction<'static>> {
180        match kind {
181            MaybeNaNKind::F32 => [
182                // stack: [x, ...]; stash: ??
183                wasm_encoder::Instruction::LocalSet(stash),
184                // stack: [...]; stash: x
185                // canonical NaN
186                wasm_encoder::Instruction::F32Const(f32::from_bits(Self::CANON_NAN_B32)),
187                // stack: [canon(NaN), ...]; stash: x
188                wasm_encoder::Instruction::LocalGet(stash),
189                // stack: [x, canon(NaN), ...]; stash: x
190                wasm_encoder::Instruction::LocalGet(stash),
191                // stack: [x, x, canon(NaN), ...]; stash: x
192                wasm_encoder::Instruction::LocalGet(stash),
193                // stack: [x, x, x, canon(NaN), ...]; stash: x
194                // isNaN: x != x
195                wasm_encoder::Instruction::F32Ne,
196                // stack: [isNaN, x, canon(NaN), ...]; stash: x
197                // select expects the stack [c: isNaN, val2: x, val1: canon(NaN), ...]
198                // select returns if c == 0 { val2 } else { val1 }
199                // here if isNaN  then c = 1 and val1 = canon(NaN) is returned
200                //      if !isNaN then c = 0 and val2 = x is returned
201                wasm_encoder::Instruction::Select,
202                // stack: [canon(x), ...]; stash: x
203            ],
204            MaybeNaNKind::F64 => [
205                // stack: [x, ...]; stash: ??
206                wasm_encoder::Instruction::LocalSet(stash),
207                // stack: [...]; stash: x
208                // canonical NaN
209                wasm_encoder::Instruction::F64Const(f64::from_bits(Self::CANON_NAN_B64)),
210                // stack: [canon(NaN), ...]; stash: x
211                wasm_encoder::Instruction::LocalGet(stash),
212                // stack: [x, canon(NaN), ...]; stash: x
213                wasm_encoder::Instruction::LocalGet(stash),
214                // stack: [x, x, canon(NaN), ...]; stash: x
215                wasm_encoder::Instruction::LocalGet(stash),
216                // stack: [x, x, x, canon(NaN), ...]; stash: x
217                // isNaN: x != x
218                wasm_encoder::Instruction::F64Ne,
219                // stack: [isNaN, x, canon(NaN), ...]; stash: x
220                // select expects the stack [c: isNaN, val2: x, val1: canon(NaN), ...]
221                // select returns if c == 0 { val2 } else { val1 }
222                // here if isNaN  then c = 1 and val1 = canon(NaN) is returned
223                //      if !isNaN then c = 0 and val2 = x is returned
224                wasm_encoder::Instruction::Select,
225                // stack: [canon(x), ...]; stash: x
226            ],
227            MaybeNaNKind::F32x4 => [
228                // stack: [x, ...]; stash: ??
229                wasm_encoder::Instruction::LocalSet(stash),
230                // stack: [...]; stash: x
231                // canonical NaN
232                wasm_encoder::Instruction::V128Const(i128::from_le_bytes(
233                    Self::CANON_NAN_B32X4.to_le_bytes(),
234                )),
235                // stack: [canon(NaN), ...]; stash: x
236                wasm_encoder::Instruction::LocalGet(stash),
237                // stack: [x, canon(NaN), ...]; stash: x
238                wasm_encoder::Instruction::LocalGet(stash),
239                // stack: [x, x, canon(NaN), ...]; stash: x
240                wasm_encoder::Instruction::LocalGet(stash),
241                // stack: [x, x, x, canon(NaN), ...]; stash: x
242                // isNaN: x != x
243                wasm_encoder::Instruction::F32x4Ne,
244                // stack: [isNaN, x, canon(NaN), ...]; stash: x
245                // bitselect expects the stack [c: isNaN, val2: x, val1: canon(NaN), ...]
246                // bitselect returns if c[i] == 0 { val2[i] } else { val1[i] }
247                // here if per-lane isNaN  then c = 1 and val1 = canon(NaN) is returned
248                //      if per-lane !isNaN then c = 0 and val2 = x is returned
249                wasm_encoder::Instruction::V128Bitselect,
250                // stack: [canon(x), ...]; stash: x
251            ],
252            MaybeNaNKind::F64x2 => [
253                // stack: [x, ...]; stash: ??
254                wasm_encoder::Instruction::LocalSet(stash),
255                // stack: [...]; stash: x
256                // canonical NaN
257                wasm_encoder::Instruction::V128Const(i128::from_le_bytes(
258                    Self::CANON_NAN_B64X2.to_le_bytes(),
259                )),
260                // stack: [canon(NaN), ...]; stash: x
261                wasm_encoder::Instruction::LocalGet(stash),
262                // stack: [x, canon(NaN), ...]; stash: x
263                wasm_encoder::Instruction::LocalGet(stash),
264                // stack: [x, x, canon(NaN), ...]; stash: x
265                wasm_encoder::Instruction::LocalGet(stash),
266                // stack: [x, x, x, canon(NaN), ...]; stash: x
267                // isNaN: x != x
268                wasm_encoder::Instruction::F64x2Ne,
269                // stack: [isNaN, x, canon(NaN), ...]; stash: x
270                // bitselect expects the stack [c: isNaN, val2: x, val1: canon(NaN), ...]
271                // bitselect returns if c[i] == 0 { val2[i] } else { val1[i] }
272                // here if per-lane isNaN  then c = 1 and val1 = canon(NaN) is returned
273                //      if per-lane !isNaN then c = 0 and val2 = x is returned
274                wasm_encoder::Instruction::V128Bitselect,
275                // stack: [canon(x), ...]; stash: x
276            ],
277        }
278    }
279
280    #[expect(clippy::too_many_lines)]
281    fn may_produce_non_deterministic_nan(
282        instr: &wasmparser::Operator,
283    ) -> Result<Option<MaybeNaNKind>, NonDeterministicWasmFeature> {
284        match instr {
285            // === MVP ===
286            // non-float operation
287            wasmparser::Operator::Unreachable
288            | wasmparser::Operator::Nop
289            | wasmparser::Operator::Block { .. }
290            | wasmparser::Operator::Loop { .. }
291            | wasmparser::Operator::If { .. }
292            | wasmparser::Operator::Else => Ok(None),
293            // === Exception handling ===
294            // non-float operation
295            wasmparser::Operator::TryTable { .. }
296            | wasmparser::Operator::Throw { .. }
297            | wasmparser::Operator::ThrowRef => Ok(None),
298            // === Legacy exception handling (deprecated) ===
299            // non-float operation
300            wasmparser::Operator::Try { .. }
301            | wasmparser::Operator::Catch { .. }
302            | wasmparser::Operator::Rethrow { .. }
303            | wasmparser::Operator::Delegate { .. }
304            | wasmparser::Operator::CatchAll => Ok(None),
305            // === MVP ===
306            // non-float operation
307            wasmparser::Operator::End
308            | wasmparser::Operator::Br { .. }
309            | wasmparser::Operator::BrIf { .. }
310            | wasmparser::Operator::BrTable { .. }
311            | wasmparser::Operator::Return
312            | wasmparser::Operator::Call { .. }
313            | wasmparser::Operator::CallIndirect { .. } => Ok(None),
314            // === Tail calls ===
315            // non-float operation
316            wasmparser::Operator::ReturnCall { .. }
317            | wasmparser::Operator::ReturnCallIndirect { .. } => Ok(None),
318            // === MVP ===
319            // non-float operation
320            wasmparser::Operator::Drop | wasmparser::Operator::Select => Ok(None),
321            // === Reference types ===
322            // non-float operation
323            wasmparser::Operator::TypedSelect { .. } => Ok(None),
324            // locals may contain floats, but get/set/tee are deterministic
325            wasmparser::Operator::LocalGet { .. }
326            | wasmparser::Operator::LocalSet { .. }
327            | wasmparser::Operator::LocalTee { .. } => Ok(None),
328            // non-float operation
329            wasmparser::Operator::GlobalGet { .. }
330            | wasmparser::Operator::GlobalSet { .. }
331            | wasmparser::Operator::I32Load { .. }
332            | wasmparser::Operator::I64Load { .. } => Ok(None),
333            // loading a float from memory is deterministic, even when a
334            //  non-canonical NaN value is loaded
335            wasmparser::Operator::F32Load { .. } | wasmparser::Operator::F64Load { .. } => Ok(None),
336            // non-float operation
337            wasmparser::Operator::I32Load8S { .. }
338            | wasmparser::Operator::I32Load8U { .. }
339            | wasmparser::Operator::I32Load16S { .. }
340            | wasmparser::Operator::I32Load16U { .. }
341            | wasmparser::Operator::I64Load8S { .. }
342            | wasmparser::Operator::I64Load8U { .. }
343            | wasmparser::Operator::I64Load16S { .. }
344            | wasmparser::Operator::I64Load16U { .. }
345            | wasmparser::Operator::I64Load32S { .. }
346            | wasmparser::Operator::I64Load32U { .. }
347            | wasmparser::Operator::I32Store { .. }
348            | wasmparser::Operator::I64Store { .. } => Ok(None),
349            // storing a float to memory is deterministic, even when a
350            //  non-canonical NaN value is stored
351            wasmparser::Operator::F32Store { .. } | wasmparser::Operator::F64Store { .. } => {
352                Ok(None)
353            }
354            // non-float operation
355            wasmparser::Operator::I32Store8 { .. }
356            | wasmparser::Operator::I32Store16 { .. }
357            | wasmparser::Operator::I64Store8 { .. }
358            | wasmparser::Operator::I64Store16 { .. }
359            | wasmparser::Operator::I64Store32 { .. }
360            | wasmparser::Operator::MemorySize { .. }
361            | wasmparser::Operator::MemoryGrow { .. }
362            | wasmparser::Operator::I32Const { .. }
363            | wasmparser::Operator::I64Const { .. } => Ok(None),
364            // constant float values are deterministic, even when they represent
365            //  non-canonical NaN values
366            wasmparser::Operator::F32Const { .. } | wasmparser::Operator::F64Const { .. } => {
367                Ok(None)
368            }
369            // === Reference types ===
370            // non-float operation
371            wasmparser::Operator::RefNull { .. }
372            | wasmparser::Operator::RefIsNull
373            | wasmparser::Operator::RefFunc { .. } => Ok(None),
374            // === Garbage collection ===
375            // non-float operation
376            wasmparser::Operator::RefEq => Ok(None),
377            // === MVP ===
378            // non-float operation
379            wasmparser::Operator::I32Eqz
380            | wasmparser::Operator::I32Eq
381            | wasmparser::Operator::I32Ne
382            | wasmparser::Operator::I32LtS
383            | wasmparser::Operator::I32LtU
384            | wasmparser::Operator::I32GtS
385            | wasmparser::Operator::I32GtU
386            | wasmparser::Operator::I32LeS
387            | wasmparser::Operator::I32LeU
388            | wasmparser::Operator::I32GeS
389            | wasmparser::Operator::I32GeU
390            | wasmparser::Operator::I64Eqz
391            | wasmparser::Operator::I64Eq
392            | wasmparser::Operator::I64Ne
393            | wasmparser::Operator::I64LtS
394            | wasmparser::Operator::I64LtU
395            | wasmparser::Operator::I64GtS
396            | wasmparser::Operator::I64GtU
397            | wasmparser::Operator::I64LeS
398            | wasmparser::Operator::I64LeU
399            | wasmparser::Operator::I64GeS
400            | wasmparser::Operator::I64GeU => Ok(None),
401            // deterministic float operation
402            wasmparser::Operator::F32Eq
403            | wasmparser::Operator::F32Ne
404            | wasmparser::Operator::F32Lt
405            | wasmparser::Operator::F32Gt
406            | wasmparser::Operator::F32Le
407            | wasmparser::Operator::F32Ge
408            | wasmparser::Operator::F64Eq
409            | wasmparser::Operator::F64Ne
410            | wasmparser::Operator::F64Lt
411            | wasmparser::Operator::F64Gt
412            | wasmparser::Operator::F64Le
413            | wasmparser::Operator::F64Ge => Ok(None),
414            // non-float operation
415            wasmparser::Operator::I32Clz
416            | wasmparser::Operator::I32Ctz
417            | wasmparser::Operator::I32Popcnt
418            | wasmparser::Operator::I32Add
419            | wasmparser::Operator::I32Sub
420            | wasmparser::Operator::I32Mul
421            | wasmparser::Operator::I32DivS
422            | wasmparser::Operator::I32DivU
423            | wasmparser::Operator::I32RemS
424            | wasmparser::Operator::I32RemU
425            | wasmparser::Operator::I32And
426            | wasmparser::Operator::I32Or
427            | wasmparser::Operator::I32Xor
428            | wasmparser::Operator::I32Shl
429            | wasmparser::Operator::I32ShrS
430            | wasmparser::Operator::I32ShrU
431            | wasmparser::Operator::I32Rotl
432            | wasmparser::Operator::I32Rotr
433            | wasmparser::Operator::I64Clz
434            | wasmparser::Operator::I64Ctz
435            | wasmparser::Operator::I64Popcnt
436            | wasmparser::Operator::I64Add
437            | wasmparser::Operator::I64Sub
438            | wasmparser::Operator::I64Mul
439            | wasmparser::Operator::I64DivS
440            | wasmparser::Operator::I64DivU
441            | wasmparser::Operator::I64RemS
442            | wasmparser::Operator::I64RemU
443            | wasmparser::Operator::I64And
444            | wasmparser::Operator::I64Or
445            | wasmparser::Operator::I64Xor
446            | wasmparser::Operator::I64Shl
447            | wasmparser::Operator::I64ShrS
448            | wasmparser::Operator::I64ShrU
449            | wasmparser::Operator::I64Rotl
450            | wasmparser::Operator::I64Rotr => Ok(None),
451            // deterministic float operation
452            wasmparser::Operator::F32Abs | wasmparser::Operator::F32Neg => Ok(None),
453            // non-deterministic float operation that may produce any NaN
454            wasmparser::Operator::F32Ceil
455            | wasmparser::Operator::F32Floor
456            | wasmparser::Operator::F32Trunc
457            | wasmparser::Operator::F32Nearest
458            | wasmparser::Operator::F32Sqrt
459            | wasmparser::Operator::F32Add
460            | wasmparser::Operator::F32Sub
461            | wasmparser::Operator::F32Mul
462            | wasmparser::Operator::F32Div
463            | wasmparser::Operator::F32Min
464            | wasmparser::Operator::F32Max => Ok(Some(MaybeNaNKind::F32)),
465            // deterministic float operation
466            wasmparser::Operator::F32Copysign
467            | wasmparser::Operator::F64Abs
468            | wasmparser::Operator::F64Neg => Ok(None),
469            // non-deterministic float operation that may produce any NaN
470            wasmparser::Operator::F64Ceil
471            | wasmparser::Operator::F64Floor
472            | wasmparser::Operator::F64Trunc
473            | wasmparser::Operator::F64Nearest
474            | wasmparser::Operator::F64Sqrt
475            | wasmparser::Operator::F64Add
476            | wasmparser::Operator::F64Sub
477            | wasmparser::Operator::F64Mul
478            | wasmparser::Operator::F64Div
479            | wasmparser::Operator::F64Min
480            | wasmparser::Operator::F64Max => Ok(Some(MaybeNaNKind::F64)),
481            // deterministic float operation
482            wasmparser::Operator::F64Copysign => Ok(None),
483            // non-float operation
484            wasmparser::Operator::I32WrapI64 => Ok(None),
485            // truncate float to int, which traps to be deterministic
486            wasmparser::Operator::I32TruncF32S
487            | wasmparser::Operator::I32TruncF32U
488            | wasmparser::Operator::I32TruncF64S
489            | wasmparser::Operator::I32TruncF64U => Ok(None),
490            // non-float operation
491            wasmparser::Operator::I64ExtendI32S | wasmparser::Operator::I64ExtendI32U => Ok(None),
492            // truncate float to int, which traps to be deterministic
493            wasmparser::Operator::I64TruncF32S
494            | wasmparser::Operator::I64TruncF32U
495            | wasmparser::Operator::I64TruncF64S
496            | wasmparser::Operator::I64TruncF64U => Ok(None),
497            // convert int to float, deterministic
498            wasmparser::Operator::F32ConvertI32S
499            | wasmparser::Operator::F32ConvertI32U
500            | wasmparser::Operator::F32ConvertI64S
501            | wasmparser::Operator::F32ConvertI64U => Ok(None),
502            // non-deterministic float operation that may produce any NaN
503            wasmparser::Operator::F32DemoteF64 => Ok(Some(MaybeNaNKind::F32)),
504            // convert int to float, deterministic
505            wasmparser::Operator::F64ConvertI32S
506            | wasmparser::Operator::F64ConvertI32U
507            | wasmparser::Operator::F64ConvertI64S
508            | wasmparser::Operator::F64ConvertI64U => Ok(None),
509            // non-deterministic float operation that may produce any NaN
510            wasmparser::Operator::F64PromoteF32 => Ok(Some(MaybeNaNKind::F64)),
511            // float <-> int bit cast, deterministic
512            wasmparser::Operator::I32ReinterpretF32
513            | wasmparser::Operator::I64ReinterpretF64
514            | wasmparser::Operator::F32ReinterpretI32
515            | wasmparser::Operator::F64ReinterpretI64 => Ok(None),
516            // === Sign extension ===
517            // non-float operation
518            wasmparser::Operator::I32Extend8S
519            | wasmparser::Operator::I32Extend16S
520            | wasmparser::Operator::I64Extend8S
521            | wasmparser::Operator::I64Extend16S
522            | wasmparser::Operator::I64Extend32S => Ok(None),
523            // === Garbage collection ===
524            // non-float operation
525            wasmparser::Operator::StructNew { .. }
526            | wasmparser::Operator::StructNewDefault { .. }
527            | wasmparser::Operator::StructGet { .. }
528            | wasmparser::Operator::StructGetS { .. }
529            | wasmparser::Operator::StructGetU { .. }
530            | wasmparser::Operator::StructSet { .. }
531            | wasmparser::Operator::ArrayNew { .. }
532            | wasmparser::Operator::ArrayNewDefault { .. }
533            | wasmparser::Operator::ArrayNewFixed { .. }
534            | wasmparser::Operator::ArrayNewData { .. }
535            | wasmparser::Operator::ArrayNewElem { .. }
536            | wasmparser::Operator::ArrayGet { .. }
537            | wasmparser::Operator::ArrayGetS { .. }
538            | wasmparser::Operator::ArrayGetU { .. }
539            | wasmparser::Operator::ArraySet { .. }
540            | wasmparser::Operator::ArrayLen
541            | wasmparser::Operator::ArrayFill { .. }
542            | wasmparser::Operator::ArrayCopy { .. }
543            | wasmparser::Operator::ArrayInitData { .. }
544            | wasmparser::Operator::ArrayInitElem { .. }
545            | wasmparser::Operator::RefTestNonNull { .. }
546            | wasmparser::Operator::RefTestNullable { .. }
547            | wasmparser::Operator::RefCastNonNull { .. }
548            | wasmparser::Operator::RefCastNullable { .. }
549            | wasmparser::Operator::BrOnCast { .. }
550            | wasmparser::Operator::BrOnCastFail { .. }
551            | wasmparser::Operator::AnyConvertExtern
552            | wasmparser::Operator::ExternConvertAny
553            | wasmparser::Operator::RefI31
554            | wasmparser::Operator::I31GetS
555            | wasmparser::Operator::I31GetU => Ok(None),
556            // === Non-trapping float-to-int conversions ===
557            // truncate float to int, which saturates to be deterministic
558            wasmparser::Operator::I32TruncSatF32S
559            | wasmparser::Operator::I32TruncSatF32U
560            | wasmparser::Operator::I32TruncSatF64S
561            | wasmparser::Operator::I32TruncSatF64U
562            | wasmparser::Operator::I64TruncSatF32S
563            | wasmparser::Operator::I64TruncSatF32U
564            | wasmparser::Operator::I64TruncSatF64S
565            | wasmparser::Operator::I64TruncSatF64U => Ok(None),
566            // === Bulk memory ===
567            // non-float operation
568            wasmparser::Operator::MemoryInit { .. }
569            | wasmparser::Operator::DataDrop { .. }
570            | wasmparser::Operator::MemoryCopy { .. }
571            | wasmparser::Operator::MemoryFill { .. }
572            | wasmparser::Operator::TableInit { .. }
573            | wasmparser::Operator::ElemDrop { .. }
574            | wasmparser::Operator::TableCopy { .. } => Ok(None),
575            // === Reference types ===
576            // non-float operation
577            wasmparser::Operator::TableFill { .. }
578            | wasmparser::Operator::TableGet { .. }
579            | wasmparser::Operator::TableSet { .. }
580            | wasmparser::Operator::TableGrow { .. }
581            | wasmparser::Operator::TableSize { .. } => Ok(None),
582            // === Memory control ===
583            // non-float operation
584            wasmparser::Operator::MemoryDiscard { .. } => Ok(None),
585            // === Threads ===
586            // non-deterministic with potential data races
587            wasmparser::Operator::MemoryAtomicNotify { .. }
588            | wasmparser::Operator::MemoryAtomicWait32 { .. }
589            | wasmparser::Operator::MemoryAtomicWait64 { .. }
590            | wasmparser::Operator::AtomicFence
591            | wasmparser::Operator::I32AtomicLoad { .. }
592            | wasmparser::Operator::I64AtomicLoad { .. }
593            | wasmparser::Operator::I32AtomicLoad8U { .. }
594            | wasmparser::Operator::I32AtomicLoad16U { .. }
595            | wasmparser::Operator::I64AtomicLoad8U { .. }
596            | wasmparser::Operator::I64AtomicLoad16U { .. }
597            | wasmparser::Operator::I64AtomicLoad32U { .. }
598            | wasmparser::Operator::I32AtomicStore { .. }
599            | wasmparser::Operator::I64AtomicStore { .. }
600            | wasmparser::Operator::I32AtomicStore8 { .. }
601            | wasmparser::Operator::I32AtomicStore16 { .. }
602            | wasmparser::Operator::I64AtomicStore8 { .. }
603            | wasmparser::Operator::I64AtomicStore16 { .. }
604            | wasmparser::Operator::I64AtomicStore32 { .. }
605            | wasmparser::Operator::I32AtomicRmwAdd { .. }
606            | wasmparser::Operator::I64AtomicRmwAdd { .. }
607            | wasmparser::Operator::I32AtomicRmw8AddU { .. }
608            | wasmparser::Operator::I32AtomicRmw16AddU { .. }
609            | wasmparser::Operator::I64AtomicRmw8AddU { .. }
610            | wasmparser::Operator::I64AtomicRmw16AddU { .. }
611            | wasmparser::Operator::I64AtomicRmw32AddU { .. }
612            | wasmparser::Operator::I32AtomicRmwSub { .. }
613            | wasmparser::Operator::I64AtomicRmwSub { .. }
614            | wasmparser::Operator::I32AtomicRmw8SubU { .. }
615            | wasmparser::Operator::I32AtomicRmw16SubU { .. }
616            | wasmparser::Operator::I64AtomicRmw8SubU { .. }
617            | wasmparser::Operator::I64AtomicRmw16SubU { .. }
618            | wasmparser::Operator::I64AtomicRmw32SubU { .. }
619            | wasmparser::Operator::I32AtomicRmwAnd { .. }
620            | wasmparser::Operator::I64AtomicRmwAnd { .. }
621            | wasmparser::Operator::I32AtomicRmw8AndU { .. }
622            | wasmparser::Operator::I32AtomicRmw16AndU { .. }
623            | wasmparser::Operator::I64AtomicRmw8AndU { .. }
624            | wasmparser::Operator::I64AtomicRmw16AndU { .. }
625            | wasmparser::Operator::I64AtomicRmw32AndU { .. }
626            | wasmparser::Operator::I32AtomicRmwOr { .. }
627            | wasmparser::Operator::I64AtomicRmwOr { .. }
628            | wasmparser::Operator::I32AtomicRmw8OrU { .. }
629            | wasmparser::Operator::I32AtomicRmw16OrU { .. }
630            | wasmparser::Operator::I64AtomicRmw8OrU { .. }
631            | wasmparser::Operator::I64AtomicRmw16OrU { .. }
632            | wasmparser::Operator::I64AtomicRmw32OrU { .. }
633            | wasmparser::Operator::I32AtomicRmwXor { .. }
634            | wasmparser::Operator::I64AtomicRmwXor { .. }
635            | wasmparser::Operator::I32AtomicRmw8XorU { .. }
636            | wasmparser::Operator::I32AtomicRmw16XorU { .. }
637            | wasmparser::Operator::I64AtomicRmw8XorU { .. }
638            | wasmparser::Operator::I64AtomicRmw16XorU { .. }
639            | wasmparser::Operator::I64AtomicRmw32XorU { .. }
640            | wasmparser::Operator::I32AtomicRmwXchg { .. }
641            | wasmparser::Operator::I64AtomicRmwXchg { .. }
642            | wasmparser::Operator::I32AtomicRmw8XchgU { .. }
643            | wasmparser::Operator::I32AtomicRmw16XchgU { .. }
644            | wasmparser::Operator::I64AtomicRmw8XchgU { .. }
645            | wasmparser::Operator::I64AtomicRmw16XchgU { .. }
646            | wasmparser::Operator::I64AtomicRmw32XchgU { .. }
647            | wasmparser::Operator::I32AtomicRmwCmpxchg { .. }
648            | wasmparser::Operator::I64AtomicRmwCmpxchg { .. }
649            | wasmparser::Operator::I32AtomicRmw8CmpxchgU { .. }
650            | wasmparser::Operator::I32AtomicRmw16CmpxchgU { .. }
651            | wasmparser::Operator::I64AtomicRmw8CmpxchgU { .. }
652            | wasmparser::Operator::I64AtomicRmw16CmpxchgU { .. }
653            | wasmparser::Operator::I64AtomicRmw32CmpxchgU { .. } => {
654                Err(NonDeterministicWasmFeature::Threads)
655            }
656            // === Shared-everything threads ===
657            // non-deterministic with potential data races
658            wasmparser::Operator::GlobalAtomicGet { .. }
659            | wasmparser::Operator::GlobalAtomicSet { .. }
660            | wasmparser::Operator::GlobalAtomicRmwAdd { .. }
661            | wasmparser::Operator::GlobalAtomicRmwSub { .. }
662            | wasmparser::Operator::GlobalAtomicRmwAnd { .. }
663            | wasmparser::Operator::GlobalAtomicRmwOr { .. }
664            | wasmparser::Operator::GlobalAtomicRmwXor { .. }
665            | wasmparser::Operator::GlobalAtomicRmwXchg { .. }
666            | wasmparser::Operator::GlobalAtomicRmwCmpxchg { .. }
667            | wasmparser::Operator::TableAtomicGet { .. }
668            | wasmparser::Operator::TableAtomicSet { .. }
669            | wasmparser::Operator::TableAtomicRmwXchg { .. }
670            | wasmparser::Operator::TableAtomicRmwCmpxchg { .. }
671            | wasmparser::Operator::StructAtomicGet { .. }
672            | wasmparser::Operator::StructAtomicGetS { .. }
673            | wasmparser::Operator::StructAtomicGetU { .. }
674            | wasmparser::Operator::StructAtomicSet { .. }
675            | wasmparser::Operator::StructAtomicRmwAdd { .. }
676            | wasmparser::Operator::StructAtomicRmwSub { .. }
677            | wasmparser::Operator::StructAtomicRmwAnd { .. }
678            | wasmparser::Operator::StructAtomicRmwOr { .. }
679            | wasmparser::Operator::StructAtomicRmwXor { .. }
680            | wasmparser::Operator::StructAtomicRmwXchg { .. }
681            | wasmparser::Operator::StructAtomicRmwCmpxchg { .. }
682            | wasmparser::Operator::ArrayAtomicGet { .. }
683            | wasmparser::Operator::ArrayAtomicGetS { .. }
684            | wasmparser::Operator::ArrayAtomicGetU { .. }
685            | wasmparser::Operator::ArrayAtomicSet { .. }
686            | wasmparser::Operator::ArrayAtomicRmwAdd { .. }
687            | wasmparser::Operator::ArrayAtomicRmwSub { .. }
688            | wasmparser::Operator::ArrayAtomicRmwAnd { .. }
689            | wasmparser::Operator::ArrayAtomicRmwOr { .. }
690            | wasmparser::Operator::ArrayAtomicRmwXor { .. }
691            | wasmparser::Operator::ArrayAtomicRmwXchg { .. }
692            | wasmparser::Operator::ArrayAtomicRmwCmpxchg { .. }
693            | wasmparser::Operator::RefI31Shared => {
694                Err(NonDeterministicWasmFeature::SharedEverythingThreads)
695            }
696            // === SIMD ===
697            // non-float operation, memory loads/stores are deterministic
698            wasmparser::Operator::V128Load { .. }
699            | wasmparser::Operator::V128Load8x8S { .. }
700            | wasmparser::Operator::V128Load8x8U { .. }
701            | wasmparser::Operator::V128Load16x4S { .. }
702            | wasmparser::Operator::V128Load16x4U { .. }
703            | wasmparser::Operator::V128Load32x2S { .. }
704            | wasmparser::Operator::V128Load32x2U { .. }
705            | wasmparser::Operator::V128Load8Splat { .. }
706            | wasmparser::Operator::V128Load16Splat { .. }
707            | wasmparser::Operator::V128Load32Splat { .. }
708            | wasmparser::Operator::V128Load64Splat { .. }
709            | wasmparser::Operator::V128Load32Zero { .. }
710            | wasmparser::Operator::V128Load64Zero { .. }
711            | wasmparser::Operator::V128Store { .. }
712            | wasmparser::Operator::V128Load8Lane { .. }
713            | wasmparser::Operator::V128Load16Lane { .. }
714            | wasmparser::Operator::V128Load32Lane { .. }
715            | wasmparser::Operator::V128Load64Lane { .. }
716            | wasmparser::Operator::V128Store8Lane { .. }
717            | wasmparser::Operator::V128Store16Lane { .. }
718            | wasmparser::Operator::V128Store32Lane { .. }
719            | wasmparser::Operator::V128Store64Lane { .. } => Ok(None),
720            // constant values are deterministic, even when they represent
721            //  non-canonical NaN values
722            wasmparser::Operator::V128Const { .. } => Ok(None),
723            // non-float operation
724            wasmparser::Operator::I8x16Shuffle { .. }
725            | wasmparser::Operator::I8x16ExtractLaneS { .. }
726            | wasmparser::Operator::I8x16ExtractLaneU { .. }
727            | wasmparser::Operator::I8x16ReplaceLane { .. }
728            | wasmparser::Operator::I16x8ExtractLaneS { .. }
729            | wasmparser::Operator::I16x8ExtractLaneU { .. }
730            | wasmparser::Operator::I16x8ReplaceLane { .. }
731            | wasmparser::Operator::I32x4ExtractLane { .. }
732            | wasmparser::Operator::I32x4ReplaceLane { .. }
733            | wasmparser::Operator::I64x2ExtractLane { .. }
734            | wasmparser::Operator::I64x2ReplaceLane { .. } => Ok(None),
735            // extracting or replacing lanes is deterministic
736            wasmparser::Operator::F32x4ExtractLane { .. }
737            | wasmparser::Operator::F32x4ReplaceLane { .. }
738            | wasmparser::Operator::F64x2ExtractLane { .. }
739            | wasmparser::Operator::F64x2ReplaceLane { .. } => Ok(None),
740            // non-float operation
741            wasmparser::Operator::I8x16Swizzle
742            | wasmparser::Operator::I8x16Splat
743            | wasmparser::Operator::I16x8Splat
744            | wasmparser::Operator::I32x4Splat
745            | wasmparser::Operator::I64x2Splat => Ok(None),
746            // splatting is deterministic, even when a non-canonical NaN value
747            //  is splatted
748            wasmparser::Operator::F32x4Splat | wasmparser::Operator::F64x2Splat => Ok(None),
749            // non-float operation
750            wasmparser::Operator::I8x16Eq
751            | wasmparser::Operator::I8x16Ne
752            | wasmparser::Operator::I8x16LtS
753            | wasmparser::Operator::I8x16LtU
754            | wasmparser::Operator::I8x16GtS
755            | wasmparser::Operator::I8x16GtU
756            | wasmparser::Operator::I8x16LeS
757            | wasmparser::Operator::I8x16LeU
758            | wasmparser::Operator::I8x16GeS
759            | wasmparser::Operator::I8x16GeU
760            | wasmparser::Operator::I16x8Eq
761            | wasmparser::Operator::I16x8Ne
762            | wasmparser::Operator::I16x8LtS
763            | wasmparser::Operator::I16x8LtU
764            | wasmparser::Operator::I16x8GtS
765            | wasmparser::Operator::I16x8GtU
766            | wasmparser::Operator::I16x8LeS
767            | wasmparser::Operator::I16x8LeU
768            | wasmparser::Operator::I16x8GeS
769            | wasmparser::Operator::I16x8GeU
770            | wasmparser::Operator::I32x4Eq
771            | wasmparser::Operator::I32x4Ne
772            | wasmparser::Operator::I32x4LtS
773            | wasmparser::Operator::I32x4LtU
774            | wasmparser::Operator::I32x4GtS
775            | wasmparser::Operator::I32x4GtU
776            | wasmparser::Operator::I32x4LeS
777            | wasmparser::Operator::I32x4LeU
778            | wasmparser::Operator::I32x4GeS
779            | wasmparser::Operator::I32x4GeU
780            | wasmparser::Operator::I64x2Eq
781            | wasmparser::Operator::I64x2Ne
782            | wasmparser::Operator::I64x2LtS
783            | wasmparser::Operator::I64x2GtS
784            | wasmparser::Operator::I64x2LeS
785            | wasmparser::Operator::I64x2GeS => Ok(None),
786            // deterministic float operation
787            wasmparser::Operator::F32x4Eq
788            | wasmparser::Operator::F32x4Ne
789            | wasmparser::Operator::F32x4Lt
790            | wasmparser::Operator::F32x4Gt
791            | wasmparser::Operator::F32x4Le
792            | wasmparser::Operator::F32x4Ge
793            | wasmparser::Operator::F64x2Eq
794            | wasmparser::Operator::F64x2Ne
795            | wasmparser::Operator::F64x2Lt
796            | wasmparser::Operator::F64x2Gt
797            | wasmparser::Operator::F64x2Le
798            | wasmparser::Operator::F64x2Ge => Ok(None),
799            // non-float operation
800            wasmparser::Operator::V128Not
801            | wasmparser::Operator::V128And
802            | wasmparser::Operator::V128AndNot
803            | wasmparser::Operator::V128Or
804            | wasmparser::Operator::V128Xor
805            | wasmparser::Operator::V128Bitselect
806            | wasmparser::Operator::V128AnyTrue
807            | wasmparser::Operator::I8x16Abs
808            | wasmparser::Operator::I8x16Neg
809            | wasmparser::Operator::I8x16Popcnt
810            | wasmparser::Operator::I8x16AllTrue
811            | wasmparser::Operator::I8x16Bitmask
812            | wasmparser::Operator::I8x16NarrowI16x8S
813            | wasmparser::Operator::I8x16NarrowI16x8U
814            | wasmparser::Operator::I8x16Shl
815            | wasmparser::Operator::I8x16ShrS
816            | wasmparser::Operator::I8x16ShrU
817            | wasmparser::Operator::I8x16Add
818            | wasmparser::Operator::I8x16AddSatS
819            | wasmparser::Operator::I8x16AddSatU
820            | wasmparser::Operator::I8x16Sub
821            | wasmparser::Operator::I8x16SubSatS
822            | wasmparser::Operator::I8x16SubSatU
823            | wasmparser::Operator::I8x16MinS
824            | wasmparser::Operator::I8x16MinU
825            | wasmparser::Operator::I8x16MaxS
826            | wasmparser::Operator::I8x16MaxU
827            | wasmparser::Operator::I8x16AvgrU
828            | wasmparser::Operator::I16x8ExtAddPairwiseI8x16S
829            | wasmparser::Operator::I16x8ExtAddPairwiseI8x16U
830            | wasmparser::Operator::I16x8Abs
831            | wasmparser::Operator::I16x8Neg
832            | wasmparser::Operator::I16x8Q15MulrSatS
833            | wasmparser::Operator::I16x8AllTrue
834            | wasmparser::Operator::I16x8Bitmask
835            | wasmparser::Operator::I16x8NarrowI32x4S
836            | wasmparser::Operator::I16x8NarrowI32x4U
837            | wasmparser::Operator::I16x8ExtendLowI8x16S
838            | wasmparser::Operator::I16x8ExtendHighI8x16S
839            | wasmparser::Operator::I16x8ExtendLowI8x16U
840            | wasmparser::Operator::I16x8ExtendHighI8x16U
841            | wasmparser::Operator::I16x8Shl
842            | wasmparser::Operator::I16x8ShrS
843            | wasmparser::Operator::I16x8ShrU
844            | wasmparser::Operator::I16x8Add
845            | wasmparser::Operator::I16x8AddSatS
846            | wasmparser::Operator::I16x8AddSatU
847            | wasmparser::Operator::I16x8Sub
848            | wasmparser::Operator::I16x8SubSatS
849            | wasmparser::Operator::I16x8SubSatU
850            | wasmparser::Operator::I16x8Mul
851            | wasmparser::Operator::I16x8MinS
852            | wasmparser::Operator::I16x8MinU
853            | wasmparser::Operator::I16x8MaxS
854            | wasmparser::Operator::I16x8MaxU
855            | wasmparser::Operator::I16x8AvgrU
856            | wasmparser::Operator::I16x8ExtMulLowI8x16S
857            | wasmparser::Operator::I16x8ExtMulHighI8x16S
858            | wasmparser::Operator::I16x8ExtMulLowI8x16U
859            | wasmparser::Operator::I16x8ExtMulHighI8x16U
860            | wasmparser::Operator::I32x4ExtAddPairwiseI16x8S
861            | wasmparser::Operator::I32x4ExtAddPairwiseI16x8U
862            | wasmparser::Operator::I32x4Abs
863            | wasmparser::Operator::I32x4Neg
864            | wasmparser::Operator::I32x4AllTrue
865            | wasmparser::Operator::I32x4Bitmask
866            | wasmparser::Operator::I32x4ExtendLowI16x8S
867            | wasmparser::Operator::I32x4ExtendHighI16x8S
868            | wasmparser::Operator::I32x4ExtendLowI16x8U
869            | wasmparser::Operator::I32x4ExtendHighI16x8U
870            | wasmparser::Operator::I32x4Shl
871            | wasmparser::Operator::I32x4ShrS
872            | wasmparser::Operator::I32x4ShrU
873            | wasmparser::Operator::I32x4Add
874            | wasmparser::Operator::I32x4Sub
875            | wasmparser::Operator::I32x4Mul
876            | wasmparser::Operator::I32x4MinS
877            | wasmparser::Operator::I32x4MinU
878            | wasmparser::Operator::I32x4MaxS
879            | wasmparser::Operator::I32x4MaxU
880            | wasmparser::Operator::I32x4DotI16x8S
881            | wasmparser::Operator::I32x4ExtMulLowI16x8S
882            | wasmparser::Operator::I32x4ExtMulHighI16x8S
883            | wasmparser::Operator::I32x4ExtMulLowI16x8U
884            | wasmparser::Operator::I32x4ExtMulHighI16x8U
885            | wasmparser::Operator::I64x2Abs
886            | wasmparser::Operator::I64x2Neg
887            | wasmparser::Operator::I64x2AllTrue
888            | wasmparser::Operator::I64x2Bitmask
889            | wasmparser::Operator::I64x2ExtendLowI32x4S
890            | wasmparser::Operator::I64x2ExtendHighI32x4S
891            | wasmparser::Operator::I64x2ExtendLowI32x4U
892            | wasmparser::Operator::I64x2ExtendHighI32x4U
893            | wasmparser::Operator::I64x2Shl
894            | wasmparser::Operator::I64x2ShrS
895            | wasmparser::Operator::I64x2ShrU
896            | wasmparser::Operator::I64x2Add
897            | wasmparser::Operator::I64x2Sub
898            | wasmparser::Operator::I64x2Mul
899            | wasmparser::Operator::I64x2ExtMulLowI32x4S
900            | wasmparser::Operator::I64x2ExtMulHighI32x4S
901            | wasmparser::Operator::I64x2ExtMulLowI32x4U
902            | wasmparser::Operator::I64x2ExtMulHighI32x4U => Ok(None),
903            // non-deterministic float operation that may produce any NaN
904            wasmparser::Operator::F32x4Ceil
905            | wasmparser::Operator::F32x4Floor
906            | wasmparser::Operator::F32x4Trunc
907            | wasmparser::Operator::F32x4Nearest => Ok(Some(MaybeNaNKind::F32x4)),
908            // deterministic float operation
909            wasmparser::Operator::F32x4Abs | wasmparser::Operator::F32x4Neg => Ok(None),
910            // non-deterministic float operation that may produce any NaN
911            wasmparser::Operator::F32x4Sqrt
912            | wasmparser::Operator::F32x4Add
913            | wasmparser::Operator::F32x4Sub
914            | wasmparser::Operator::F32x4Mul
915            | wasmparser::Operator::F32x4Div
916            | wasmparser::Operator::F32x4Min
917            | wasmparser::Operator::F32x4Max => Ok(Some(MaybeNaNKind::F32x4)),
918            // deterministic float operation
919            wasmparser::Operator::F32x4PMin | wasmparser::Operator::F32x4PMax => Ok(None),
920            // non-deterministic float operation that may produce any NaN
921            wasmparser::Operator::F64x2Ceil
922            | wasmparser::Operator::F64x2Floor
923            | wasmparser::Operator::F64x2Trunc
924            | wasmparser::Operator::F64x2Nearest => Ok(Some(MaybeNaNKind::F64x2)),
925            // deterministic float operation
926            wasmparser::Operator::F64x2Abs | wasmparser::Operator::F64x2Neg => Ok(None),
927            // non-deterministic float operation that may produce any NaN
928            wasmparser::Operator::F64x2Sqrt
929            | wasmparser::Operator::F64x2Add
930            | wasmparser::Operator::F64x2Sub
931            | wasmparser::Operator::F64x2Mul
932            | wasmparser::Operator::F64x2Div
933            | wasmparser::Operator::F64x2Min
934            | wasmparser::Operator::F64x2Max => Ok(Some(MaybeNaNKind::F64x2)),
935            // deterministic float operation
936            wasmparser::Operator::F64x2PMin | wasmparser::Operator::F64x2PMax => Ok(None),
937            // truncate float to int, which saturates to be deterministic
938            wasmparser::Operator::I32x4TruncSatF32x4S
939            | wasmparser::Operator::I32x4TruncSatF32x4U => Ok(None),
940            // convert int to float, deterministic
941            wasmparser::Operator::F32x4ConvertI32x4S | wasmparser::Operator::F32x4ConvertI32x4U => {
942                Ok(None)
943            }
944            // truncate float to int, which saturates to be deterministic
945            wasmparser::Operator::I32x4TruncSatF64x2SZero
946            | wasmparser::Operator::I32x4TruncSatF64x2UZero => Ok(None),
947            // convert int to float, deterministic
948            wasmparser::Operator::F64x2ConvertLowI32x4S
949            | wasmparser::Operator::F64x2ConvertLowI32x4U => Ok(None),
950            // non-deterministic float operation that may produce any NaN
951            wasmparser::Operator::F32x4DemoteF64x2Zero => Ok(Some(MaybeNaNKind::F32x4)),
952            wasmparser::Operator::F64x2PromoteLowF32x4 => Ok(Some(MaybeNaNKind::F64x2)),
953            // === Relaxed SIMD ===
954            // non-deterministic, result may be platform-dependent
955            wasmparser::Operator::I8x16RelaxedSwizzle
956            | wasmparser::Operator::I32x4RelaxedTruncF32x4S
957            | wasmparser::Operator::I32x4RelaxedTruncF32x4U
958            | wasmparser::Operator::I32x4RelaxedTruncF64x2SZero
959            | wasmparser::Operator::I32x4RelaxedTruncF64x2UZero
960            | wasmparser::Operator::F32x4RelaxedMadd
961            | wasmparser::Operator::F32x4RelaxedNmadd
962            | wasmparser::Operator::F64x2RelaxedMadd
963            | wasmparser::Operator::F64x2RelaxedNmadd
964            | wasmparser::Operator::I8x16RelaxedLaneselect
965            | wasmparser::Operator::I16x8RelaxedLaneselect
966            | wasmparser::Operator::I32x4RelaxedLaneselect
967            | wasmparser::Operator::I64x2RelaxedLaneselect
968            | wasmparser::Operator::F32x4RelaxedMin
969            | wasmparser::Operator::F32x4RelaxedMax
970            | wasmparser::Operator::F64x2RelaxedMin
971            | wasmparser::Operator::F64x2RelaxedMax
972            | wasmparser::Operator::I16x8RelaxedQ15mulrS
973            | wasmparser::Operator::I16x8RelaxedDotI8x16I7x16S
974            | wasmparser::Operator::I32x4RelaxedDotI8x16I7x16AddS => {
975                Err(NonDeterministicWasmFeature::RelaxedSimd)
976            }
977            // === Typed function references ===
978            // non-float operation
979            wasmparser::Operator::CallRef { .. }
980            | wasmparser::Operator::ReturnCallRef { .. }
981            | wasmparser::Operator::RefAsNonNull
982            | wasmparser::Operator::BrOnNull { .. }
983            | wasmparser::Operator::BrOnNonNull { .. } => Ok(None),
984            // === Stack switching ===
985            // non-float operation
986            wasmparser::Operator::ContNew { .. }
987            | wasmparser::Operator::ContBind { .. }
988            | wasmparser::Operator::Suspend { .. }
989            | wasmparser::Operator::Resume { .. }
990            | wasmparser::Operator::ResumeThrow { .. }
991            | wasmparser::Operator::Switch { .. } => Ok(None),
992            // === Wide Arithmetic ===
993            // non-float operation
994            wasmparser::Operator::I64Add128
995            | wasmparser::Operator::I64Sub128
996            | wasmparser::Operator::I64MulWideS
997            | wasmparser::Operator::I64MulWideU => Ok(None),
998            // === FIXME ===
999            #[cfg(not(test))]
1000            #[expect(clippy::panic)]
1001            _ => panic!("unsupported instruction"),
1002            #[cfg(test)]
1003            #[expect(unsafe_code)]
1004            _ => {
1005                extern "C" {
1006                    fn nan_canonicaliser_unhandled_operator() -> !;
1007                }
1008                unsafe { nan_canonicaliser_unhandled_operator() }
1009            }
1010        }
1011    }
1012}
1013
1014#[derive(Copy, Clone)]
1015enum MaybeNaNKind {
1016    F32,
1017    F64,
1018    F32x4,
1019    F64x2,
1020}
1021
1022#[derive(Debug, thiserror::Error)]
1023enum NonDeterministicWasmFeature {
1024    #[error(
1025        "WASM uses the non-deterministic relaxed-simd feature, which may produce \
1026         platform-dependent results"
1027    )]
1028    RelaxedSimd,
1029    #[error("WASM uses the non-deterministic threads feature, which may produce data races")]
1030    Threads,
1031    #[error(
1032        "WASM uses the non-deterministic shared-everything threads feature, which may produce \
1033         data races"
1034    )]
1035    SharedEverythingThreads,
1036}