rusticl: add debug assertions to avoid truncating casts

v2: reorder commits for cherry-picking

Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33989>

src/gallium/frontends/rusticl/api/device.rs

@@ -346,6 +346,11 @@ fn get_device_ids(
         return Err(CL_DEVICE_NOT_FOUND);
     }
 
+    debug_assert!(
+        devs.len() <= cl_uint::MAX as usize,
+        "number of available devices exceeds `cl_uint::MAX`"
+    );
+
     // num_devices returns the number of OpenCL devices available that match device_type. If
     // num_devices is NULL, this argument is ignored.
     // SAFETY: Caller is responsible for providing a null pointer or one valid

src/gallium/frontends/rusticl/api/memory.rs

@@ -916,6 +916,11 @@ fn get_supported_image_formats(
     res.sort();
     res.dedup();
 
+    debug_assert!(
+        res.len() <= cl_uint::MAX as usize,
+        "number of supported formats exceeds `cl_uint::MAX`"
+    );
+
     // `num_image_formats` should be the full count of supported formats,
     // regardless of the value of `num_entries`. It may be null, in which case
     // it is ignored.

src/gallium/frontends/rusticl/api/types.rs

@@ -189,6 +189,13 @@ cl_callback!(
 
 impl SVMFreeCb {
     pub fn call(self, queue: &Queue, svm_pointers: &mut [usize]) {
+        // `clEnqueueSVMFree()` takes the length of the `svm_pointers` list as a
+        // `cl_uint`, so this will only occur in cases of implementation error.
+        debug_assert!(
+            svm_pointers.len() <= cl_uint::MAX as usize,
+            "svm_pointers count must not exceed `cl_uint::MAX`"
+        );
+
         let (num_svm_pointers, svm_pointers) = if !svm_pointers.is_empty() {
             (
                 svm_pointers.len() as cl_uint,