[wgpu-core] Compute minimum binding size correctly for arrays.

In early versions of WGSL, `storage` or `uniform` global variables had
to be either structs or runtime-sized arrays. This rule was relaxed,
and now globals can have any type; Naga automatically wraps such
variables in structs when required by the backend shading language.

Under the old rules, whenever wgpu-core saw a `storage` or `uniform`
global variable with an array type, it could assume it was a
runtime-sized array, and take the stride as the minimum binding size.
Under the new rules, wgpu-core must consider fixed-sized and
runtime-sized arrays separately.

CHANGELOG.md

@@ -109,6 +109,7 @@ Bottom level categories:
 - Fix the validation of vertex and index ranges. By @nical in [#5144](https://github.com/gfx-rs/wgpu/pull/5144) and [#5156](https://github.com/gfx-rs/wgpu/pull/5156)
 - Device lost callbacks are invoked when replaced and when global is dropped. By @bradwerth in [#5168](https://github.com/gfx-rs/wgpu/pull/5168)
 - Fix panic when creating a surface while no backend is available. By @wumpf [#5166](https://github.com/gfx-rs/wgpu/pull/5166)
+- Correctly compute minimum buffer size for array-typed `storage` and `uniform` vars. By @jimblandy [#5222](https://github.com/gfx-rs/wgpu/pull/5222)
 
 #### WGL
 

tests/tests/buffer.rs

@@ -174,11 +174,7 @@ static MAP_OFFSET: GpuTestConfiguration = GpuTestConfiguration::new().run_async(
 /// 16 for that variable's group/index. Pipeline creation should fail.
 #[gpu_test]
 static MINIMUM_BUFFER_BINDING_SIZE_LAYOUT: GpuTestConfiguration = GpuTestConfiguration::new()
-    .parameters(
-        TestParameters::default()
-            .test_features_limits()
-            .skip(FailureCase::always()), // https://github.com/gfx-rs/wgpu/issues/5219
-    )
+    .parameters(TestParameters::default().test_features_limits())
     .run_sync(|ctx| {
         // Create a shader module that statically uses a storage buffer.
         let shader_module = ctx
@@ -242,11 +238,7 @@ static MINIMUM_BUFFER_BINDING_SIZE_LAYOUT: GpuTestConfiguration = GpuTestConfigu
 /// binding. Command recording should fail.
 #[gpu_test]
 static MINIMUM_BUFFER_BINDING_SIZE_DISPATCH: GpuTestConfiguration = GpuTestConfiguration::new()
-    .parameters(
-        TestParameters::default()
-            .test_features_limits()
-            .skip(FailureCase::always()), // https://github.com/gfx-rs/wgpu/issues/5219
-    )
+    .parameters(TestParameters::default().test_features_limits())
     .run_sync(|ctx| {
         // This test tries to use a bindgroup layout with a
         // min_binding_size of 16 to an index whose WGSL type requires 32

wgpu-core/src/validation.rs

@@ -892,9 +892,15 @@ impl Interface {
                     class,
                 },
                 naga::TypeInner::Sampler { comparison } => ResourceType::Sampler { comparison },
-                naga::TypeInner::Array { stride, .. } => ResourceType::Buffer {
-                    size: wgt::BufferSize::new(stride as u64).unwrap(),
-                },
+                naga::TypeInner::Array { stride, size, .. } => {
+                    let size = match size {
+                        naga::ArraySize::Constant(size) => size.get() * stride,
+                        naga::ArraySize::Dynamic => stride,
+                    };
+                    ResourceType::Buffer {
+                        size: wgt::BufferSize::new(size as u64).unwrap(),
+                    }
+                }
                 ref other => ResourceType::Buffer {
                     size: wgt::BufferSize::new(other.size(module.to_ctx()) as u64).unwrap(),
                 },