Add Instance::wgsl_language_features (#6814)

* docs(naga): clarify desc. for `LanguageExtension`

* feat(naga): expose `{,Implemented,Unimplemented}LanguageExtension`

* feat(naga): expose `ImplementedLanguageExtension` as `WgslLanguageExtension`

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
Co-Authored-By: Erich Gubler <erichdongubler@gmail.com>

* feat: add `Instance::wgsl_language_features`

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
Co-Authored-By: Erich Gubler <erichdongubler@gmail.com>

* refactor: reimpl. `ImplementedLanguageExtension::all` w/ `strum::VariantArray`

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

---------

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
Co-authored-by: Erich Gubler <erichdongubler@gmail.com>

Author: sagudev

CHANGELOG.md

@@ -162,6 +162,7 @@ By @wumpf in [#6849](https://github.com/gfx-rs/wgpu/pull/6849).
 - Move raytracing alignments into HAL instead of in core. By @Vecvec in [#6563](https://github.com/gfx-rs/wgpu/pull/6563).
 - Allow for statically linking DXC rather than including separate `.dll` files. By @DouglasDwyer in [#6574](https://github.com/gfx-rs/wgpu/pull/6574).
 - `DeviceType` and `AdapterInfo` now impl `Hash` by @cwfitzgerald in [#6868](https://github.com/gfx-rs/wgpu/pull/6868)
+- Add `wgsl_language_features` for obtaining available WGSL language feature by @sagudev in [#6814](https://github.com/gfx-rs/wgpu/pull/6814)
 
 ##### Vulkan
 

Cargo.lock

@@ -75,6 +75,7 @@ codespan-reporting = { version = "0.11.0" }
 rustc-hash.workspace = true
 indexmap.workspace = true
 log = "0.4"
+strum.workspace = true
 spirv = { version = "0.3", optional = true }
 thiserror.workspace = true
 serde = { version = "1.0.217", features = ["derive"], optional = true }
@@ -102,4 +103,3 @@ ron = "0.8.0"
 rspirv = { version = "0.11", git = "https://github.com/gfx-rs/rspirv", rev = "b969f175d5663258b4891e44b76c1544da9661ab" }
 serde = { workspace = true, features = ["derive"] }
 spirv = { version = "0.3", features = ["deserialize"] }
-strum.workspace = true

naga/Cargo.toml

@@ -20,6 +20,10 @@ pub use crate::front::wgsl::error::ParseError;
 use crate::front::wgsl::lower::Lowerer;
 use crate::Scalar;
 
+pub use crate::front::wgsl::parse::directive::language_extension::{
+    ImplementedLanguageExtension, LanguageExtension, UnimplementedLanguageExtension,
+};
+
 pub struct Frontend {
     parser: Parser,
 }

naga/src/front/wgsl/mod.rs

@@ -2,11 +2,13 @@
 //!
 //! The focal point of this module is the [`LanguageExtension`] API.
 
-/// A language extension not guaranteed to be present in all environments.
+use strum::VariantArray;
+
+/// A language extension recognized by Naga, but not guaranteed to be present in all environments.
 ///
 /// WGSL spec.: <https://www.w3.org/TR/WGSL/#language-extensions-sec>
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-pub(crate) enum LanguageExtension {
+pub enum LanguageExtension {
     #[allow(unused)]
     Implemented(ImplementedLanguageExtension),
     Unimplemented(UnimplementedLanguageExtension),
@@ -41,7 +43,7 @@ impl LanguageExtension {
     /// Maps this [`LanguageExtension`] into the sentinel word associated with it in WGSL.
     pub const fn to_ident(self) -> &'static str {
         match self {
-            Self::Implemented(kind) => match kind {},
+            Self::Implemented(kind) => kind.to_ident(),
             Self::Unimplemented(kind) => match kind {
                 UnimplementedLanguageExtension::ReadOnlyAndReadWriteStorageTextures => {
                     Self::READONLY_AND_READWRITE_STORAGE_TEXTURES
@@ -61,12 +63,24 @@ impl LanguageExtension {
 }
 
 /// A variant of [`LanguageExtension::Implemented`].
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-pub(crate) enum ImplementedLanguageExtension {}
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, VariantArray)]
+pub enum ImplementedLanguageExtension {}
+
+impl ImplementedLanguageExtension {
+    /// Returns slice of all variants of [`ImplementedLanguageExtension`].
+    pub const fn all() -> &'static [Self] {
+        Self::VARIANTS
+    }
+
+    /// Maps this [`ImplementedLanguageExtension`] into the sentinel word associated with it in WGSL.
+    pub const fn to_ident(self) -> &'static str {
+        match self {}
+    }
+}
 
 /// A variant of [`LanguageExtension::Unimplemented`].
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-pub(crate) enum UnimplementedLanguageExtension {
+pub enum UnimplementedLanguageExtension {
     ReadOnlyAndReadWriteStorageTextures,
     Packed4x8IntegerDotProduct,
     UnrestrictedPointerParameters,

naga/src/front/wgsl/parse/directive/language_extension.rs

@@ -187,6 +187,7 @@ optional = true
 
 [dependencies]
 arrayvec.workspace = true
+bitflags.workspace = true
 document-features.workspace = true
 log.workspace = true
 parking_lot.workspace = true

wgpu/Cargo.toml

@@ -4,6 +4,23 @@ use crate::{dispatch::InstanceInterface, *};
 
 use std::future::Future;
 
+bitflags::bitflags! {
+    /// WGSL language extensions.
+    ///
+    /// WGSL spec.: <https://www.w3.org/TR/WGSL/#language-extensions-sec>
+    #[derive(Debug, Clone, PartialEq, PartialOrd, Ord, Eq, Hash)]
+    pub struct WgslLanguageFeatures: u32 {
+        /// <https://www.w3.org/TR/WGSL/#language_extension-readonly_and_readwrite_storage_textures>
+        const ReadOnlyAndReadWriteStorageTextures = 1 << 0;
+        /// <https://www.w3.org/TR/WGSL/#language_extension-packed_4x8_integer_dot_product>
+        const Packed4x8IntegerDotProduct = 1 << 1;
+        /// <https://www.w3.org/TR/WGSL/#language_extension-unrestricted_pointer_parameters>
+        const UnrestrictedPointerParameters = 1 << 2;
+        /// <https://www.w3.org/TR/WGSL/#language_extension-pointer_composite_access>
+        const PointerCompositeAccess = 1 << 3;
+    }
+}
+
 /// Context for all other wgpu objects. Instance of wgpu.
 ///
 /// This is the first thing you create when using wgpu.
@@ -385,4 +402,12 @@ impl Instance {
     pub fn generate_report(&self) -> Option<wgc::global::GlobalReport> {
         self.inner.as_core_opt().map(|ctx| ctx.generate_report())
     }
+
+    /// Returns set of supported WGSL language extensions supported by this instance.
+    ///
+    /// <https://www.w3.org/TR/webgpu/#gpuwgsllanguagefeatures>
+    #[cfg(feature = "wgsl")]
+    pub fn wgsl_language_features(&self) -> WgslLanguageFeatures {
+        self.inner.wgsl_language_features()
+    }
 }

wgpu/src/api/instance.rs

@@ -1563,6 +1563,40 @@ impl dispatch::InstanceInterface for ContextWebGpu {
         // Devices are automatically polled.
         true
     }
+
+    #[cfg(feature = "wgsl")]
+    fn wgsl_language_features(&self) -> crate::WgslLanguageFeatures {
+        let mut wgsl_language_features = crate::WgslLanguageFeatures::empty();
+        if let Some(gpu) = &self.gpu {
+            gpu.wgsl_language_features()
+                .keys()
+                .into_iter()
+                .map(|wlf| wlf.expect("`WgslLanguageFeatures` elements should be valid"))
+                .map(|wlf| {
+                    wlf.as_string()
+                        .expect("`WgslLanguageFeatures` should be string set")
+                })
+                .filter_map(|wlf| match wlf.as_str() {
+                    "readonly_and_readwrite_storage_textures" => {
+                        Some(crate::WgslLanguageFeatures::ReadOnlyAndReadWriteStorageTextures)
+                    }
+                    "packed_4x8_integer_dot_product" => {
+                        Some(crate::WgslLanguageFeatures::Packed4x8IntegerDotProduct)
+                    }
+                    "unrestricted_pointer_parameters" => {
+                        Some(crate::WgslLanguageFeatures::UnrestrictedPointerParameters)
+                    }
+                    "pointer_composite_access" => {
+                        Some(crate::WgslLanguageFeatures::PointerCompositeAccess)
+                    }
+                    _ => None,
+                })
+                .for_each(|wlf| {
+                    wgsl_language_features |= wlf;
+                })
+        }
+        wgsl_language_features
+    }
 }
 
 impl Drop for ContextWebGpu {

wgpu/src/backend/webgpu.rs

@@ -851,6 +851,18 @@ impl dispatch::InstanceInterface for ContextWgpuCore {
             Err(err) => self.handle_error_fatal(err, "Instance::poll_all_devices"),
         }
     }
+
+    #[cfg(feature = "wgsl")]
+    fn wgsl_language_features(&self) -> crate::WgslLanguageFeatures {
+        wgc::naga::front::wgsl::ImplementedLanguageExtension::all()
+            .iter()
+            .copied()
+            .fold(
+                crate::WgslLanguageFeatures::empty(),
+                #[allow(unreachable_code)]
+                |acc, wle| acc | match wle {},
+            )
+    }
 }
 
 impl dispatch::AdapterInterface for CoreAdapter {

wgpu/src/backend/wgpu_core.rs

@@ -100,6 +100,9 @@ pub trait InstanceInterface: CommonTraits {
     ) -> Pin<Box<dyn RequestAdapterFuture>>;
 
     fn poll_all_devices(&self, force_wait: bool) -> bool;
+
+    #[cfg(feature = "wgsl")]
+    fn wgsl_language_features(&self) -> crate::WgslLanguageFeatures;
 }
 
 pub trait AdapterInterface: CommonTraits {