spirv-std: add #[repr(C)] (and extra comments) to opaque handle types.

crates/spirv-std/src/image.rs

@@ -94,6 +94,8 @@ pub type Cubemap = crate::Image!(cube, type=f32, sampled, __crate_root=crate);
 /// See SPIR-V OpTypeImage specification for the meaning of integer parameters.
 #[spirv(generic_image_type)]
 #[derive(Copy, Clone)]
+// HACK(eddyb) avoids "transparent newtype of `_anti_zst_padding`" misinterpretation.
+#[repr(C)]
 pub struct Image<
     SampledType: SampleType<FORMAT>,
     const DIM: u32,          // Dimensionality,
@@ -103,7 +105,9 @@ pub struct Image<
     const SAMPLED: u32,      // Sampled,
     const FORMAT: u32,       // ImageFormat,
 > {
-    _x: u32,
+    // HACK(eddyb) avoids the layout becoming ZST (and being elided in one way
+    // or another, before `#[spirv(generic_image_type)]` can special-case it).
+    _anti_zst_padding: core::mem::MaybeUninit<u32>,
     _marker: core::marker::PhantomData<SampledType>,
 }
 

crates/spirv-std/src/ray_tracing.rs

@@ -7,8 +7,12 @@ use core::arch::asm;
 /// acceleration structure handle as defined in the client API specification.
 #[spirv(acceleration_structure)]
 #[derive(Copy, Clone)]
+// HACK(eddyb) avoids "transparent newtype of `_anti_zst_padding`" misinterpretation.
+#[repr(C)]
 pub struct AccelerationStructure {
-    pub(crate) _private: u32,
+    // HACK(eddyb) avoids the layout becoming ZST (and being elided in one way
+    // or another, before `#[spirv(acceleration_structure)]` can special-case it).
+    _anti_zst_padding: core::mem::MaybeUninit<u32>,
 }
 
 impl AccelerationStructure {
@@ -186,8 +190,12 @@ pub enum CommittedIntersection {
 
 /// A ray query type which is an opaque object representing a ray traversal.
 #[spirv(ray_query)]
+// HACK(eddyb) avoids "transparent newtype of `_anti_zst_padding`" misinterpretation.
+#[repr(C)]
 pub struct RayQuery {
-    _private: u32,
+    // HACK(eddyb) avoids the layout becoming ZST (and being elided in one way
+    // or another, before `#[spirv(ray_query)]` can special-case it).
+    _anti_zst_padding: core::mem::MaybeUninit<u32>,
 }
 
 /// Constructs an uninitialized ray query variable. Using the syntax

crates/spirv-std/src/runtime_array.rs

@@ -7,9 +7,12 @@ use core::marker::PhantomData;
 /// Hence, this type represents something very similar to a slice, but with no way of knowing its
 /// length.
 #[spirv(runtime_array)]
+// HACK(eddyb) avoids "transparent newtype of `_anti_zst_padding`" misinterpretation.
+#[repr(C)]
 pub struct RuntimeArray<T> {
-    // spooky! this field does not exist, so if it's referenced in rust code, things will explode
-    _do_not_touch: u32,
+    // HACK(eddyb) avoids the layout becoming ZST (and being elided in one way
+    // or another, before `#[spirv(runtime_array)]` can special-case it).
+    _anti_zst_padding: core::mem::MaybeUninit<u32>,
     _phantom: PhantomData<T>,
 }
 

crates/spirv-std/src/sampler.rs

@@ -2,6 +2,10 @@
 /// sample an image.
 #[spirv(sampler)]
 #[derive(Copy, Clone)]
+// HACK(eddyb) avoids "transparent newtype of `_anti_zst_padding`" misinterpretation.
+#[repr(C)]
 pub struct Sampler {
-    _x: u32,
+    // HACK(eddyb) avoids the layout becoming ZST (and being elided in one way
+    // or another, before `#[spirv(sampler)]` can special-case it).
+    _anti_zst_padding: core::mem::MaybeUninit<u32>,
 }

tests/ui/image/gather_err.stderr

@@ -9,9 +9,9 @@ error[E0277]: the trait bound `Image<f32, 0, 2, 0, 0, 1, 0>: HasGather` is not s
               Image<SampledType, 3, DEPTH, ARRAYED, 0, SAMPLED, FORMAT>
               Image<SampledType, 4, DEPTH, ARRAYED, 0, SAMPLED, FORMAT>
 note: required by a bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, spirv_std::::image::{impl#1}::{constant#0}, SAMPLED, FORMAT>::gather`
-   --> $SPIRV_STD_SRC/image.rs:163:15
+   --> $SPIRV_STD_SRC/image.rs:167:15
     |
-163 |         Self: HasGather,
+167 |         Self: HasGather,
     |               ^^^^^^^^^ required by this bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, spirv_std::::image::{impl#1}::{constant#0}, SAMPLED, FORMAT>::gather`
 
 error[E0277]: the trait bound `Image<f32, 2, 2, 0, 0, 1, 0>: HasGather` is not satisfied
@@ -25,9 +25,9 @@ error[E0277]: the trait bound `Image<f32, 2, 2, 0, 0, 1, 0>: HasGather` is not s
               Image<SampledType, 3, DEPTH, ARRAYED, 0, SAMPLED, FORMAT>
               Image<SampledType, 4, DEPTH, ARRAYED, 0, SAMPLED, FORMAT>
 note: required by a bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, spirv_std::::image::{impl#1}::{constant#0}, SAMPLED, FORMAT>::gather`
-   --> $SPIRV_STD_SRC/image.rs:163:15
+   --> $SPIRV_STD_SRC/image.rs:167:15
     |
-163 |         Self: HasGather,
+167 |         Self: HasGather,
     |               ^^^^^^^^^ required by this bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, spirv_std::::image::{impl#1}::{constant#0}, SAMPLED, FORMAT>::gather`
 
 error: aborting due to 2 previous errors

tests/ui/image/query/query_levels_err.stderr

@@ -10,9 +10,9 @@ error[E0277]: the trait bound `Image<f32, 4, 2, 0, 0, 1, 0>: HasQueryLevels` is
               Image<SampledType, 2, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>
               Image<SampledType, 3, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>
 note: required by a bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>::query_levels`
-   --> $SPIRV_STD_SRC/image.rs:813:15
+   --> $SPIRV_STD_SRC/image.rs:817:15
     |
-813 |         Self: HasQueryLevels,
+817 |         Self: HasQueryLevels,
     |               ^^^^^^^^^^^^^^ required by this bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>::query_levels`
 
 error: aborting due to previous error

tests/ui/image/query/query_lod_err.stderr

@@ -10,9 +10,9 @@ error[E0277]: the trait bound `Image<f32, 4, 2, 0, 0, 1, 0>: HasQueryLevels` is
               Image<SampledType, 2, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>
               Image<SampledType, 3, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>
 note: required by a bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>::query_lod`
-   --> $SPIRV_STD_SRC/image.rs:839:15
+   --> $SPIRV_STD_SRC/image.rs:843:15
     |
-839 |         Self: HasQueryLevels,
+843 |         Self: HasQueryLevels,
     |               ^^^^^^^^^^^^^^ required by this bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>::query_lod`
 
 error: aborting due to previous error

tests/ui/image/query/query_size_err.stderr

@@ -15,9 +15,9 @@ error[E0277]: the trait bound `Image<f32, 1, 2, 0, 0, 1, 0>: HasQuerySize` is no
               Image<SampledType, 2, DEPTH, ARRAYED, 0, 2, FORMAT>
             and 6 others
 note: required by a bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>::query_size`
-   --> $SPIRV_STD_SRC/image.rs:870:15
+   --> $SPIRV_STD_SRC/image.rs:874:15
     |
-870 |         Self: HasQuerySize,
+874 |         Self: HasQuerySize,
     |               ^^^^^^^^^^^^ required by this bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, MULTISAMPLED, SAMPLED, FORMAT>::query_size`
 
 error: aborting due to previous error

tests/ui/image/query/query_size_lod_err.stderr

@@ -10,9 +10,9 @@ error[E0277]: the trait bound `Image<f32, 4, 2, 0, 0, 1, 0>: HasQuerySizeLod` is
               Image<SampledType, 2, DEPTH, ARRAYED, 0, SAMPLED, FORMAT>
               Image<SampledType, 3, DEPTH, ARRAYED, 0, SAMPLED, FORMAT>
 note: required by a bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, spirv_std::::image::{impl#7}::{constant#0}, SAMPLED, FORMAT>::query_size_lod`
-   --> $SPIRV_STD_SRC/image.rs:903:15
+   --> $SPIRV_STD_SRC/image.rs:907:15
     |
-903 |         Self: HasQuerySizeLod,
+907 |         Self: HasQuerySizeLod,
     |               ^^^^^^^^^^^^^^^ required by this bound in `Image::<SampledType, DIM, DEPTH, ARRAYED, spirv_std::::image::{impl#7}::{constant#0}, SAMPLED, FORMAT>::query_size_lod`
 
 error: aborting due to previous error