metrics: properly annotate required features for 64-bit-only metrics (#7449)

tokio/src/macros/cfg.rs

@@ -1,5 +1,26 @@
 #![allow(unused_macros)]
 
+/// Allows specifying arbitrary combinations of features and config flags,
+/// which are also propagated to `docsrs` config.
+///
+/// Each contained item will have the annotations applied
+///
+/// ## Example usage:
+/// ```no-compile
+/// feature! {
+/// #![any(
+///     feature = "process",
+///     feature = "sync",
+///     feature = "rt",
+///     tokio_unstable
+/// )]
+///     /// docs
+///     pub struct MyStruct {};
+///     /// docs
+///     pub struct AnotherStruct {};
+/// }
+/// ```
+///
 macro_rules! feature {
     (
         #![$meta:meta]

tokio/src/runtime/metrics/runtime.rs

@@ -342,8 +342,13 @@ impl RuntimeMetrics {
                 .worker_metrics(worker)
                 .thread_id()
         }
+    }
 
-        cfg_64bit_metrics! {
+    feature! {
+        #![all(
+            tokio_unstable,
+            target_has_atomic = "64"
+        )]
         /// Returns the number of tasks spawned in this runtime since it was created.
         ///
         /// This count starts at zero when the runtime is created and increases by one each time a task is spawned.
@@ -683,6 +688,8 @@ impl RuntimeMetrics {
         }
     }
 
+    cfg_unstable_metrics! {
+
         /// Renamed to [`RuntimeMetrics::global_queue_depth`]
         #[deprecated = "Renamed to global_queue_depth"]
         #[doc(hidden)]
@@ -877,8 +884,13 @@ impl RuntimeMetrics {
         pub fn poll_count_histogram_bucket_range(&self, bucket: usize) -> Range<Duration> {
             self.poll_time_histogram_bucket_range(bucket)
         }
+    }
 
-        cfg_64bit_metrics! {
+    feature! {
+    #![all(
+        tokio_unstable,
+        target_has_atomic = "64"
+    )]
         /// Returns the number of times the given worker polled tasks with a poll
         /// duration within the given bucket's range.
         ///
@@ -992,6 +1004,7 @@ impl RuntimeMetrics {
         }
     }
 
+    cfg_unstable_metrics! {
         /// Returns the number of tasks currently scheduled in the blocking
         /// thread pool, spawned using `spawn_blocking`.
         ///
@@ -1015,9 +1028,14 @@ impl RuntimeMetrics {
         pub fn blocking_queue_depth(&self) -> usize {
             self.handle.inner.blocking_queue_depth()
         }
+    }
 
-        cfg_net! {
-            cfg_64bit_metrics! {
+    feature! {
+        #![all(
+            tokio_unstable,
+            target_has_atomic = "64",
+            feature = "net"
+        )]
             /// Returns the number of file descriptors that have been registered with the
             /// runtime's I/O driver.
             ///
@@ -1103,5 +1121,3 @@ impl RuntimeMetrics {
             }
     }
 }
-    }
-}