wgsl: validate struct parsing

[dj2]

• [x] struct a {} -- invalid (empty struct)
• [ ] struct { a: i32, } -- invalid no name
• [ ] invalid duplicate struct name

struct a { a: i32, };
struct a { b: i32, };

• [ ] struct a { a : i32, a: f32 } -- invalid duplicate member name
• [ ] struct a b: i32} -- invalid missing {
• [ ] struct a { b: i32 -- invalid missing }
• [ ] struct 123 { a: i32} --invalid name
• [ ] struct a { a: i32; b:i32;} -- invalid ; instead of ,
• [ ] struct a { a: i32 b: i32} -- invalid missing ,
• [x] struct a { a: i32, b: i32,} -- valid trailing ,
• [x] struct a { a: i32,} -- single element valid
• [ ] valid substructure

struct a { b: f32 };
struct b { c: a };

• [ ] struct a { b: i32}; var a = 1; -- invalid usage of a shadows struct name
• [ ] struct a { b i32} -- invalid declaration inside struct decl
• [x] struct a { b: array<f32> } -- valid runtime array
• [x] struct a { b: array<f32>, c: i32} -- invalid runtime array must be last
• [x] struct a { b: texture_3d} -- invalid
• [x] struct a { b: sampler } -- invalid
• [x] all types -- valid

struct B {
  a: i32
};
struct a {
  a: i32,
  b: f32,
  c: u32,
  d: mat2x3<f32>,
  e: vec3<f32>,
  f: atomic<i32>,
  g: array<B, 4>,
  h: B,
 i: array<f32>
}

• [x] struct B { a: array<i32>}; struct a { b: B } -- invalid as runtime array must be in outer struct

• [ ] struct/*comment*/B\n\n{\na/*comment*/: i32} -- valid

• [x] struct a { b: ptr<workgroup, i32>} -- invalid no pointers

• [ ] type a = i32; struct b { c: a} -- valid

• [ ] struct a { @builtin(position) @location(1) a : vec4<f32>} --invalid only one of

• [ ] struct a { @builtin(position) a : vec4<f32> } -- valid

• [ ] struct a { @location(0) b: f32} -- valid

• [ ] struct a { @location(0) @interpolate(flat) b: f32} -- valid

• [ ] struct a { @interpolate(perspective, centroid) @location(2) b: f32} -- valid

• [ ] struct a { @builtin(position) @invariant a : vec4<f32>} -- valid

• [ ] struct a { @invariant @builtin(position) a : vec4<f32>} -- valid

• [ ] struct a { @binding(0) b: f32} -- invalid

• [ ] struct a { @group(1) b: f32} -- invalid

• [ ] struct a { @id(1) b: f32} -- invalid

• [ ] struct a { @interpolate(flat) @builtin(position) b: vec4<f32>} -- invalid

• [ ] struct a { @invariant @location(0) b: f32} -- invalid

• [ ] struct a { @workgroup_size(1) b: f32} -- invalid

• [ ] multiple builtins (test each of the builtins for each of the valid and invalid stages

Align and size rules for storage class

• [x] struct a { @align(32) b: vec3<f32>} -- valid
• [x] struct a { @align(0) b: f32 } --invalid
• [x] struct a { @align(7) b: f32 } -- invalid not power of 2
• [ ] struct a { @align(2) b: i32} -- invalid align must be at least 4
• [ ] struct a { @align(4) @size(4) b: atomic<i32>} -- valid
• [ ] struct a { @size(4) @align(4) b: atomic<i32>} -- valid
• [ ] struct a { @align(8) @size(7) b: i32, @align(256) @size(1025) c: f32} -- valid
• [x] struct a { @align(32) @align(16) b: f32} -- invalid
• [x] struct a { @size(32) @size(16) b: f32} -- invalid

Align and size rules for uniform class

• [ ] struct a { b : array<f32, 7> } -- invalid stride must be 16 and not 4
• [ ] struct a { @size(16) b: array<f32, 7>} -- valid
• [ ] struct b { c: i32}; struct a { d: b} -- invalid as size of b must be 16 and not 4

[dj2]

• Size tests https://github.com/gpuweb/cts/blob/main/src/webgpu/shader/validation/shader_io/size.spec.ts
• Align tests https://github.com/gpuweb/cts/blob/main/src/webgpu/shader/validation/parse/align.spec.ts
• Struct tests https://github.com/gpuweb/cts/blob/main/src/webgpu/shader/validation/types/struct.spec.ts