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
/*!
Shader validator.
*/

mod analyzer;
mod compose;
mod expression;
mod function;
mod handles;
mod interface;
mod r#type;

use crate::{
    arena::Handle,
    proc::{ExpressionKindTracker, LayoutError, Layouter, TypeResolution},
    FastHashSet,
};
use bit_set::BitSet;
use std::ops;

//TODO: analyze the model at the same time as we validate it,
// merge the corresponding matches over expressions and statements.

use crate::span::{AddSpan as _, WithSpan};
pub use analyzer::{ExpressionInfo, FunctionInfo, GlobalUse, Uniformity, UniformityRequirements};
pub use compose::ComposeError;
pub use expression::{check_literal_value, LiteralError};
pub use expression::{ConstExpressionError, ExpressionError};
pub use function::{CallError, FunctionError, LocalVariableError};
pub use interface::{EntryPointError, GlobalVariableError, VaryingError};
pub use r#type::{Disalignment, TypeError, TypeFlags, WidthError};

use self::handles::InvalidHandleError;

bitflags::bitflags! {
    /// Validation flags.
    ///
    /// If you are working with trusted shaders, then you may be able
    /// to save some time by skipping validation.
    ///
    /// If you do not perform full validation, invalid shaders may
    /// cause Naga to panic. If you do perform full validation and
    /// [`Validator::validate`] returns `Ok`, then Naga promises that
    /// code generation will either succeed or return an error; it
    /// should never panic.
    ///
    /// The default value for `ValidationFlags` is
    /// `ValidationFlags::all()`.
    #[cfg_attr(feature = "serialize", derive(serde::Serialize))]
    #[cfg_attr(feature = "deserialize", derive(serde::Deserialize))]
    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    pub struct ValidationFlags: u8 {
        /// Expressions.
        const EXPRESSIONS = 0x1;
        /// Statements and blocks of them.
        const BLOCKS = 0x2;
        /// Uniformity of control flow for operations that require it.
        const CONTROL_FLOW_UNIFORMITY = 0x4;
        /// Host-shareable structure layouts.
        const STRUCT_LAYOUTS = 0x8;
        /// Constants.
        const CONSTANTS = 0x10;
        /// Group, binding, and location attributes.
        const BINDINGS = 0x20;
    }
}

impl Default for ValidationFlags {
    fn default() -> Self {
        Self::all()
    }
}

bitflags::bitflags! {
    /// Allowed IR capabilities.
    #[must_use]
    #[cfg_attr(feature = "serialize", derive(serde::Serialize))]
    #[cfg_attr(feature = "deserialize", derive(serde::Deserialize))]
    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    pub struct Capabilities: u32 {
        /// Support for [`AddressSpace:PushConstant`].
        const PUSH_CONSTANT = 0x1;
        /// Float values with width = 8.
        const FLOAT64 = 0x2;
        /// Support for [`Builtin:PrimitiveIndex`].
        const PRIMITIVE_INDEX = 0x4;
        /// Support for non-uniform indexing of sampled textures and storage buffer arrays.
        const SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING = 0x8;
        /// Support for non-uniform indexing of uniform buffers and storage texture arrays.
        const UNIFORM_BUFFER_AND_STORAGE_TEXTURE_ARRAY_NON_UNIFORM_INDEXING = 0x10;
        /// Support for non-uniform indexing of samplers.
        const SAMPLER_NON_UNIFORM_INDEXING = 0x20;
        /// Support for [`Builtin::ClipDistance`].
        const CLIP_DISTANCE = 0x40;
        /// Support for [`Builtin::CullDistance`].
        const CULL_DISTANCE = 0x80;
        /// Support for 16-bit normalized storage texture formats.
        const STORAGE_TEXTURE_16BIT_NORM_FORMATS = 0x100;
        /// Support for [`BuiltIn::ViewIndex`].
        const MULTIVIEW = 0x200;
        /// Support for `early_depth_test`.
        const EARLY_DEPTH_TEST = 0x400;
        /// Support for [`Builtin::SampleIndex`] and [`Sampling::Sample`].
        const MULTISAMPLED_SHADING = 0x800;
        /// Support for ray queries and acceleration structures.
        const RAY_QUERY = 0x1000;
        /// Support for generating two sources for blending from fragment shaders.
        const DUAL_SOURCE_BLENDING = 0x2000;
        /// Support for arrayed cube textures.
        const CUBE_ARRAY_TEXTURES = 0x4000;
        /// Support for 64-bit signed and unsigned integers.
        const SHADER_INT64 = 0x8000;
        /// Support for subgroup operations.
        const SUBGROUP = 0x10000;
        /// Support for subgroup barriers.
        const SUBGROUP_BARRIER = 0x20000;
    }
}

impl Default for Capabilities {
    fn default() -> Self {
        Self::MULTISAMPLED_SHADING | Self::CUBE_ARRAY_TEXTURES
    }
}

bitflags::bitflags! {
    /// Supported subgroup operations
    #[cfg_attr(feature = "serialize", derive(serde::Serialize))]
    #[cfg_attr(feature = "deserialize", derive(serde::Deserialize))]
    #[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
    pub struct SubgroupOperationSet: u8 {
        /// Elect, Barrier
        const BASIC = 1 << 0;
        /// Any, All
        const VOTE = 1 << 1;
        /// reductions, scans
        const ARITHMETIC = 1 << 2;
        /// ballot, broadcast
        const BALLOT = 1 << 3;
        /// shuffle, shuffle xor
        const SHUFFLE = 1 << 4;
        /// shuffle up, down
        const SHUFFLE_RELATIVE = 1 << 5;
        // We don't support these operations yet
        // /// Clustered
        // const CLUSTERED = 1 << 6;
        // /// Quad supported
        // const QUAD_FRAGMENT_COMPUTE = 1 << 7;
        // /// Quad supported in all stages
        // const QUAD_ALL_STAGES = 1 << 8;
    }
}

impl super::SubgroupOperation {
    const fn required_operations(&self) -> SubgroupOperationSet {
        use SubgroupOperationSet as S;
        match *self {
            Self::All | Self::Any => S::VOTE,
            Self::Add | Self::Mul | Self::Min | Self::Max | Self::And | Self::Or | Self::Xor => {
                S::ARITHMETIC
            }
        }
    }
}

impl super::GatherMode {
    const fn required_operations(&self) -> SubgroupOperationSet {
        use SubgroupOperationSet as S;
        match *self {
            Self::BroadcastFirst | Self::Broadcast(_) => S::BALLOT,
            Self::Shuffle(_) | Self::ShuffleXor(_) => S::SHUFFLE,
            Self::ShuffleUp(_) | Self::ShuffleDown(_) => S::SHUFFLE_RELATIVE,
        }
    }
}

bitflags::bitflags! {
    /// Validation flags.
    #[cfg_attr(feature = "serialize", derive(serde::Serialize))]
    #[cfg_attr(feature = "deserialize", derive(serde::Deserialize))]
    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    pub struct ShaderStages: u8 {
        const VERTEX = 0x1;
        const FRAGMENT = 0x2;
        const COMPUTE = 0x4;
    }
}

#[derive(Debug, Clone)]
#[cfg_attr(feature = "serialize", derive(serde::Serialize))]
#[cfg_attr(feature = "deserialize", derive(serde::Deserialize))]
pub struct ModuleInfo {
    type_flags: Vec<TypeFlags>,
    functions: Vec<FunctionInfo>,
    entry_points: Vec<FunctionInfo>,
    const_expression_types: Box<[TypeResolution]>,
}

impl ops::Index<Handle<crate::Type>> for ModuleInfo {
    type Output = TypeFlags;
    fn index(&self, handle: Handle<crate::Type>) -> &Self::Output {
        &self.type_flags[handle.index()]
    }
}

impl ops::Index<Handle<crate::Function>> for ModuleInfo {
    type Output = FunctionInfo;
    fn index(&self, handle: Handle<crate::Function>) -> &Self::Output {
        &self.functions[handle.index()]
    }
}

impl ops::Index<Handle<crate::Expression>> for ModuleInfo {
    type Output = TypeResolution;
    fn index(&self, handle: Handle<crate::Expression>) -> &Self::Output {
        &self.const_expression_types[handle.index()]
    }
}

#[derive(Debug)]
pub struct Validator {
    flags: ValidationFlags,
    capabilities: Capabilities,
    subgroup_stages: ShaderStages,
    subgroup_operations: SubgroupOperationSet,
    types: Vec<r#type::TypeInfo>,
    layouter: Layouter,
    location_mask: BitSet,
    ep_resource_bindings: FastHashSet<crate::ResourceBinding>,
    #[allow(dead_code)]
    switch_values: FastHashSet<crate::SwitchValue>,
    valid_expression_list: Vec<Handle<crate::Expression>>,
    valid_expression_set: BitSet,
    override_ids: FastHashSet<u16>,
    allow_overrides: bool,
}

#[derive(Clone, Debug, thiserror::Error)]
#[cfg_attr(test, derive(PartialEq))]
pub enum ConstantError {
    #[error("Initializer must be a const-expression")]
    InitializerExprType,
    #[error("The type doesn't match the constant")]
    InvalidType,
    #[error("The type is not constructible")]
    NonConstructibleType,
}

#[derive(Clone, Debug, thiserror::Error)]
#[cfg_attr(test, derive(PartialEq))]
pub enum OverrideError {
    #[error("Override name and ID are missing")]
    MissingNameAndID,
    #[error("Override ID must be unique")]
    DuplicateID,
    #[error("Initializer must be a const-expression or override-expression")]
    InitializerExprType,
    #[error("The type doesn't match the override")]
    InvalidType,
    #[error("The type is not constructible")]
    NonConstructibleType,
    #[error("The type is not a scalar")]
    TypeNotScalar,
    #[error("Override declarations are not allowed")]
    NotAllowed,
}

#[derive(Clone, Debug, thiserror::Error)]
#[cfg_attr(test, derive(PartialEq))]
pub enum ValidationError {
    #[error(transparent)]
    InvalidHandle(#[from] InvalidHandleError),
    #[error(transparent)]
    Layouter(#[from] LayoutError),
    #[error("Type {handle:?} '{name}' is invalid")]
    Type {
        handle: Handle<crate::Type>,
        name: String,
        source: TypeError,
    },
    #[error("Constant expression {handle:?} is invalid")]
    ConstExpression {
        handle: Handle<crate::Expression>,
        source: ConstExpressionError,
    },
    #[error("Constant {handle:?} '{name}' is invalid")]
    Constant {
        handle: Handle<crate::Constant>,
        name: String,
        source: ConstantError,
    },
    #[error("Override {handle:?} '{name}' is invalid")]
    Override {
        handle: Handle<crate::Override>,
        name: String,
        source: OverrideError,
    },
    #[error("Global variable {handle:?} '{name}' is invalid")]
    GlobalVariable {
        handle: Handle<crate::GlobalVariable>,
        name: String,
        source: GlobalVariableError,
    },
    #[error("Function {handle:?} '{name}' is invalid")]
    Function {
        handle: Handle<crate::Function>,
        name: String,
        source: FunctionError,
    },
    #[error("Entry point {name} at {stage:?} is invalid")]
    EntryPoint {
        stage: crate::ShaderStage,
        name: String,
        source: EntryPointError,
    },
    #[error("Module is corrupted")]
    Corrupted,
}

impl crate::TypeInner {
    const fn is_sized(&self) -> bool {
        match *self {
            Self::Scalar { .. }
            | Self::Vector { .. }
            | Self::Matrix { .. }
            | Self::Array {
                size: crate::ArraySize::Constant(_),
                ..
            }
            | Self::Atomic { .. }
            | Self::Pointer { .. }
            | Self::ValuePointer { .. }
            | Self::Struct { .. } => true,
            Self::Array { .. }
            | Self::Image { .. }
            | Self::Sampler { .. }
            | Self::AccelerationStructure
            | Self::RayQuery
            | Self::BindingArray { .. } => false,
        }
    }

    /// Return the `ImageDimension` for which `self` is an appropriate coordinate.
    const fn image_storage_coordinates(&self) -> Option<crate::ImageDimension> {
        match *self {
            Self::Scalar(crate::Scalar {
                kind: crate::ScalarKind::Sint | crate::ScalarKind::Uint,
                ..
            }) => Some(crate::ImageDimension::D1),
            Self::Vector {
                size: crate::VectorSize::Bi,
                scalar:
                    crate::Scalar {
                        kind: crate::ScalarKind::Sint | crate::ScalarKind::Uint,
                        ..
                    },
            } => Some(crate::ImageDimension::D2),
            Self::Vector {
                size: crate::VectorSize::Tri,
                scalar:
                    crate::Scalar {
                        kind: crate::ScalarKind::Sint | crate::ScalarKind::Uint,
                        ..
                    },
            } => Some(crate::ImageDimension::D3),
            _ => None,
        }
    }
}

impl Validator {
    /// Construct a new validator instance.
    pub fn new(flags: ValidationFlags, capabilities: Capabilities) -> Self {
        Validator {
            flags,
            capabilities,
            subgroup_stages: ShaderStages::empty(),
            subgroup_operations: SubgroupOperationSet::empty(),
            types: Vec::new(),
            layouter: Layouter::default(),
            location_mask: BitSet::new(),
            ep_resource_bindings: FastHashSet::default(),
            switch_values: FastHashSet::default(),
            valid_expression_list: Vec::new(),
            valid_expression_set: BitSet::new(),
            override_ids: FastHashSet::default(),
            allow_overrides: true,
        }
    }

    pub fn subgroup_stages(&mut self, stages: ShaderStages) -> &mut Self {
        self.subgroup_stages = stages;
        self
    }

    pub fn subgroup_operations(&mut self, operations: SubgroupOperationSet) -> &mut Self {
        self.subgroup_operations = operations;
        self
    }

    /// Reset the validator internals
    pub fn reset(&mut self) {
        self.types.clear();
        self.layouter.clear();
        self.location_mask.clear();
        self.ep_resource_bindings.clear();
        self.switch_values.clear();
        self.valid_expression_list.clear();
        self.valid_expression_set.clear();
        self.override_ids.clear();
    }

    fn validate_constant(
        &self,
        handle: Handle<crate::Constant>,
        gctx: crate::proc::GlobalCtx,
        mod_info: &ModuleInfo,
        global_expr_kind: &ExpressionKindTracker,
    ) -> Result<(), ConstantError> {
        let con = &gctx.constants[handle];

        let type_info = &self.types[con.ty.index()];
        if !type_info.flags.contains(TypeFlags::CONSTRUCTIBLE) {
            return Err(ConstantError::NonConstructibleType);
        }

        if !global_expr_kind.is_const(con.init) {
            return Err(ConstantError::InitializerExprType);
        }

        let decl_ty = &gctx.types[con.ty].inner;
        let init_ty = mod_info[con.init].inner_with(gctx.types);
        if !decl_ty.equivalent(init_ty, gctx.types) {
            return Err(ConstantError::InvalidType);
        }

        Ok(())
    }

    fn validate_override(
        &mut self,
        handle: Handle<crate::Override>,
        gctx: crate::proc::GlobalCtx,
        mod_info: &ModuleInfo,
    ) -> Result<(), OverrideError> {
        if !self.allow_overrides {
            return Err(OverrideError::NotAllowed);
        }

        let o = &gctx.overrides[handle];

        if o.name.is_none() && o.id.is_none() {
            return Err(OverrideError::MissingNameAndID);
        }

        if let Some(id) = o.id {
            if !self.override_ids.insert(id) {
                return Err(OverrideError::DuplicateID);
            }
        }

        let type_info = &self.types[o.ty.index()];
        if !type_info.flags.contains(TypeFlags::CONSTRUCTIBLE) {
            return Err(OverrideError::NonConstructibleType);
        }

        let decl_ty = &gctx.types[o.ty].inner;
        match decl_ty {
            &crate::TypeInner::Scalar(scalar) => match scalar {
                crate::Scalar::BOOL
                | crate::Scalar::I32
                | crate::Scalar::U32
                | crate::Scalar::F32
                | crate::Scalar::F64 => {}
                _ => return Err(OverrideError::TypeNotScalar),
            },
            _ => return Err(OverrideError::TypeNotScalar),
        }

        if let Some(init) = o.init {
            let init_ty = mod_info[init].inner_with(gctx.types);
            if !decl_ty.equivalent(init_ty, gctx.types) {
                return Err(OverrideError::InvalidType);
            }
        }

        Ok(())
    }

    /// Check the given module to be valid.
    pub fn validate(
        &mut self,
        module: &crate::Module,
    ) -> Result<ModuleInfo, WithSpan<ValidationError>> {
        self.allow_overrides = true;
        self.validate_impl(module)
    }

    /// Check the given module to be valid.
    ///
    /// With the additional restriction that overrides are not present.
    pub fn validate_no_overrides(
        &mut self,
        module: &crate::Module,
    ) -> Result<ModuleInfo, WithSpan<ValidationError>> {
        self.allow_overrides = false;
        self.validate_impl(module)
    }

    fn validate_impl(
        &mut self,
        module: &crate::Module,
    ) -> Result<ModuleInfo, WithSpan<ValidationError>> {
        self.reset();
        self.reset_types(module.types.len());

        Self::validate_module_handles(module).map_err(|e| e.with_span())?;

        self.layouter.update(module.to_ctx()).map_err(|e| {
            let handle = e.ty;
            ValidationError::from(e).with_span_handle(handle, &module.types)
        })?;

        // These should all get overwritten.
        let placeholder = TypeResolution::Value(crate::TypeInner::Scalar(crate::Scalar {
            kind: crate::ScalarKind::Bool,
            width: 0,
        }));

        let mut mod_info = ModuleInfo {
            type_flags: Vec::with_capacity(module.types.len()),
            functions: Vec::with_capacity(module.functions.len()),
            entry_points: Vec::with_capacity(module.entry_points.len()),
            const_expression_types: vec![placeholder; module.global_expressions.len()]
                .into_boxed_slice(),
        };

        for (handle, ty) in module.types.iter() {
            let ty_info = self
                .validate_type(handle, module.to_ctx())
                .map_err(|source| {
                    ValidationError::Type {
                        handle,
                        name: ty.name.clone().unwrap_or_default(),
                        source,
                    }
                    .with_span_handle(handle, &module.types)
                })?;
            mod_info.type_flags.push(ty_info.flags);
            self.types[handle.index()] = ty_info;
        }

        {
            let t = crate::Arena::new();
            let resolve_context = crate::proc::ResolveContext::with_locals(module, &t, &[]);
            for (handle, _) in module.global_expressions.iter() {
                mod_info
                    .process_const_expression(handle, &resolve_context, module.to_ctx())
                    .map_err(|source| {
                        ValidationError::ConstExpression { handle, source }
                            .with_span_handle(handle, &module.global_expressions)
                    })?
            }
        }

        let global_expr_kind = ExpressionKindTracker::from_arena(&module.global_expressions);

        if self.flags.contains(ValidationFlags::CONSTANTS) {
            for (handle, _) in module.global_expressions.iter() {
                self.validate_const_expression(
                    handle,
                    module.to_ctx(),
                    &mod_info,
                    &global_expr_kind,
                )
                .map_err(|source| {
                    ValidationError::ConstExpression { handle, source }
                        .with_span_handle(handle, &module.global_expressions)
                })?
            }

            for (handle, constant) in module.constants.iter() {
                self.validate_constant(handle, module.to_ctx(), &mod_info, &global_expr_kind)
                    .map_err(|source| {
                        ValidationError::Constant {
                            handle,
                            name: constant.name.clone().unwrap_or_default(),
                            source,
                        }
                        .with_span_handle(handle, &module.constants)
                    })?
            }

            for (handle, override_) in module.overrides.iter() {
                self.validate_override(handle, module.to_ctx(), &mod_info)
                    .map_err(|source| {
                        ValidationError::Override {
                            handle,
                            name: override_.name.clone().unwrap_or_default(),
                            source,
                        }
                        .with_span_handle(handle, &module.overrides)
                    })?
            }
        }

        for (var_handle, var) in module.global_variables.iter() {
            self.validate_global_var(var, module.to_ctx(), &mod_info, &global_expr_kind)
                .map_err(|source| {
                    ValidationError::GlobalVariable {
                        handle: var_handle,
                        name: var.name.clone().unwrap_or_default(),
                        source,
                    }
                    .with_span_handle(var_handle, &module.global_variables)
                })?;
        }

        for (handle, fun) in module.functions.iter() {
            match self.validate_function(fun, module, &mod_info, false, &global_expr_kind) {
                Ok(info) => mod_info.functions.push(info),
                Err(error) => {
                    return Err(error.and_then(|source| {
                        ValidationError::Function {
                            handle,
                            name: fun.name.clone().unwrap_or_default(),
                            source,
                        }
                        .with_span_handle(handle, &module.functions)
                    }))
                }
            }
        }

        let mut ep_map = FastHashSet::default();
        for ep in module.entry_points.iter() {
            if !ep_map.insert((ep.stage, &ep.name)) {
                return Err(ValidationError::EntryPoint {
                    stage: ep.stage,
                    name: ep.name.clone(),
                    source: EntryPointError::Conflict,
                }
                .with_span()); // TODO: keep some EP span information?
            }

            match self.validate_entry_point(ep, module, &mod_info, &global_expr_kind) {
                Ok(info) => mod_info.entry_points.push(info),
                Err(error) => {
                    return Err(error.and_then(|source| {
                        ValidationError::EntryPoint {
                            stage: ep.stage,
                            name: ep.name.clone(),
                            source,
                        }
                        .with_span()
                    }));
                }
            }
        }

        Ok(mod_info)
    }
}

fn validate_atomic_compare_exchange_struct(
    types: &crate::UniqueArena<crate::Type>,
    members: &[crate::StructMember],
    scalar_predicate: impl FnOnce(&crate::TypeInner) -> bool,
) -> bool {
    members.len() == 2
        && members[0].name.as_deref() == Some("old_value")
        && scalar_predicate(&types[members[0].ty].inner)
        && members[1].name.as_deref() == Some("exchanged")
        && types[members[1].ty].inner == crate::TypeInner::Scalar(crate::Scalar::BOOL)
}