abi layout difftest: cuda and scalar-math feature forwarding

Author: Firestar99

tests/difftests/tests/Cargo.lock

@@ -5,9 +5,14 @@ edition.workspace = true
 [lints]
 workspace = true
 
+[features]
+cuda = ["glam/cuda"]
+scalar-math = ["glam/scalar-math"]
+
 # GPU deps
 [dependencies]
 spirv-std.workspace = true
+glam.workspace = true
 bytemuck.workspace = true
 
 # CPU deps (for the test harness)

tests/difftests/tests/lang/abi/vector_layout/cpu/Cargo.toml

@@ -1,7 +1,9 @@
+use crate::glam_features::GlamFeatures;
 use crate::layout::{LAYOUT_COUNT, LAYOUT_LEN, eval_layouts};
 use difftest::config::Config;
 
-pub fn run() {
+pub fn run(glam_feature: GlamFeatures) {
+    glam_feature.assert();
     let config = Config::from_path(std::env::args().nth(1).unwrap()).unwrap();
     let mut out = vec![0; LAYOUT_LEN];
     for gid in 0..LAYOUT_COUNT {

tests/difftests/tests/lang/abi/vector_layout/cpu/src/cpu_driver.rs

@@ -0,0 +1,35 @@
+#[repr(u32)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum GlamFeatures {
+    Default,
+    Cuda,
+    ScalarMath,
+}
+
+impl GlamFeatures {
+    pub fn is(&self) -> bool {
+        match self {
+            // cuda: 16 (!)
+            // cuda + scalar-math: 8
+            // scalar-math: (native) 4
+            GlamFeatures::Default => align_of::<glam::Mat2>() == 16 && !GlamFeatures::Cuda.is(),
+            // default, scalar-math: (native) 4
+            GlamFeatures::Cuda => align_of::<glam::Vec2>() == 8,
+            // default, cuda: 16
+            GlamFeatures::ScalarMath => align_of::<glam::Vec4>() == 4,
+        }
+    }
+
+    pub fn assert(&self) {
+        for feature in [Self::Default, Self::Cuda, Self::ScalarMath] {
+            if *self == feature {
+                assert!(feature.is(), "Expected feature {feature:?} to be enabled");
+            } else {
+                assert!(
+                    !feature.is(),
+                    "Feature {feature:?} mistakenly enabled! Too aggressive feature unification?"
+                );
+            }
+        }
+    }
+}

tests/difftests/tests/lang/abi/vector_layout/cpu/src/glam_features.rs

@@ -2,6 +2,7 @@
 
 #[cfg(not(target_arch = "spirv"))]
 pub mod cpu_driver;
+pub mod glam_features;
 pub mod layout;
 pub mod shader;
 #[cfg(not(target_arch = "spirv"))]

tests/difftests/tests/lang/abi/vector_layout/cpu/src/lib.rs

@@ -1,3 +1,5 @@
+use abi_vector_layout_cpu::glam_features::GlamFeatures;
+
 fn main() {
-    abi_vector_layout_cpu::cpu_driver::run();
+    abi_vector_layout_cpu::cpu_driver::run(GlamFeatures::Default);
 }

tests/difftests/tests/lang/abi/vector_layout/cpu/src/main.rs

@@ -1,8 +1,10 @@
+use crate::glam_features::GlamFeatures;
 use crate::layout::{LAYOUT_COUNT, LAYOUT_LEN};
 use difftest::config::Config;
 use difftest::scaffold::compute::{BufferConfig, RustComputeShader, WgpuComputeTestMultiBuffer};
 
-pub fn run() {
+pub fn run(glam_feature: GlamFeatures) {
+    glam_feature.assert();
     let config = Config::from_path(std::env::args().nth(1).unwrap()).unwrap();
     let test = WgpuComputeTestMultiBuffer::new(
         RustComputeShader::default(),

tests/difftests/tests/lang/abi/vector_layout/cpu/src/shader_driver.rs

@@ -1,3 +1,5 @@
+use abi_vector_layout_cpu::glam_features::GlamFeatures;
+
 fn main() {
-    abi_vector_layout_cpu::shader_driver::run();
+    abi_vector_layout_cpu::shader_driver::run(GlamFeatures::Default);
 }