chore: separate new unsafe ops into blocks

Unsafe operations can be exhausting to validate by themselves. Therefore, it's often interesting to
separate these out so we can justify each individual operation, and let a human reader accumulate
and drop supporting safety context in the smallest increments necessary. To that end, this commit
can pave the way for future work where we may do something like enable
[`clippy::undocumented_unsafe_blocks`], which calls out `unsafe` blocks that do not have a `SAFETY`
comment immediately above them.

This commit only separates the operations in `unsafe` blocks I added in this same PR; I'm
deliberately leaving existing `unsafe` blocks alone, ATM.

[`clippy::undocumented_unsafe_blocks`]: https://rust-lang.github.io/rust-clippy/stable/index.html#undocumented_unsafe_blocks

wgpu-core/src/track/mod.rs

@@ -420,12 +420,9 @@ impl<A: hub::HalApi> ResourceMetadataProvider<'_, A> {
             }
             ResourceMetadataProvider::Indirect { metadata } => {
                 metadata.tracker_assert_in_bounds(index);
-                (unsafe { *metadata.epochs.get_unchecked(index) }, unsafe {
-                    metadata
-                        .ref_counts
-                        .get_unchecked(index)
-                        .clone()
-                        .unwrap_unchecked()
+                (unsafe { *metadata.epochs.get_unchecked(index) }, {
+                    let ref_count = unsafe { metadata.ref_counts.get_unchecked(index) };
+                    unsafe { ref_count.clone().unwrap_unchecked() }
                 })
             }
             ResourceMetadataProvider::Resource { epoch } => {

wgpu-core/src/track/texture.rs

@@ -291,9 +291,10 @@ impl<A: hub::HalApi> TextureUsageScope<A> {
             self.tracker_assert_in_bounds(index);
             scope.tracker_assert_in_bounds(index);
 
+            let texture_data = unsafe { texture_data_from_texture(storage, index32) };
             unsafe {
                 insert_or_merge(
-                    texture_data_from_texture(storage, index32),
+                    texture_data,
                     &mut self.set,
                     &mut self.metadata,
                     index32,
@@ -359,9 +360,10 @@ impl<A: hub::HalApi> TextureUsageScope<A> {
 
         self.tracker_assert_in_bounds(index);
 
+        let texture_data = unsafe { texture_data_from_texture(storage, index32) };
         unsafe {
             insert_or_merge(
-                texture_data_from_texture(storage, index32),
+                texture_data,
                 &mut self.set,
                 &mut self.metadata,
                 index32,
@@ -467,13 +469,8 @@ impl<A: hub::HalApi> TextureTracker<A> {
 
         self.tracker_assert_in_bounds(index);
 
-        unsafe {
-            self.metadata
-                .ref_counts
-                .get_unchecked(index)
-                .as_ref()
-                .unwrap_unchecked()
-        }
+        let ref_count = unsafe { self.metadata.ref_counts.get_unchecked(index) };
+        unsafe { ref_count.as_ref().unwrap_unchecked() }
     }
 
     /// Inserts a single texture and a state into the resource tracker.
@@ -683,9 +680,10 @@ impl<A: hub::HalApi> TextureTracker<A> {
             if unsafe { !scope.metadata.owned.get(index).unwrap_unchecked() } {
                 continue;
             }
+            let texture_data = unsafe { texture_data_from_texture(storage, index32) };
             unsafe {
                 insert_or_barrier_update(
-                    texture_data_from_texture(storage, index32),
+                    texture_data,
                     Some(&mut self.start_set),
                     &mut self.end_set,
                     &mut self.metadata,

wgpu-hal/src/vulkan/device.rs

@@ -48,13 +48,16 @@ impl super::DeviceShared {
                 .collect();
             &buffer_vec
         };
+
+        let name = unsafe { CStr::from_bytes_with_nul_unchecked(name_bytes) };
+
         let _result = unsafe {
             extension.debug_utils_set_object_name(
                 self.raw.handle(),
                 &vk::DebugUtilsObjectNameInfoEXT::builder()
                     .object_type(object_type)
                     .object_handle(object.as_raw())
-                    .object_name(CStr::from_bytes_with_nul_unchecked(name_bytes)),
+                    .object_name(name),
             )
         };
     }