Precompute hashCode in BuildConfigurationValue.Key.

Since it is always interned, there's no reason to lazily compute the hash code - it will be called by the interner.

PiperOrigin-RevId: 368515456

src/main/java/com/google/devtools/build/lib/skyframe/BuildConfigurationValue.java

@@ -138,9 +138,8 @@ public static final class Key implements SkyKey, Serializable {
     private static final Interner<Key> keyInterner = BlazeInterners.newWeakInterner();
 
     private final FragmentClassSet fragments;
-    final BuildOptions.OptionsDiffForReconstruction optionsDiff;
-    // If hashCode really is -1, we'll recompute it from scratch each time. Oh well.
-    private volatile int hashCode = -1;
+    private final BuildOptions.OptionsDiffForReconstruction optionsDiff;
+    private final int hashCode;
 
     @AutoCodec.Instantiator
     @VisibleForSerialization
@@ -152,6 +151,7 @@ static Key create(
     private Key(FragmentClassSet fragments, BuildOptions.OptionsDiffForReconstruction optionsDiff) {
       this.fragments = Preconditions.checkNotNull(fragments);
       this.optionsDiff = Preconditions.checkNotNull(optionsDiff);
+      this.hashCode = Objects.hash(fragments, optionsDiff);
     }
 
     @VisibleForTesting
@@ -182,9 +182,6 @@ public boolean equals(Object o) {
 
     @Override
     public int hashCode() {
-      if (hashCode == -1) {
-        hashCode = Objects.hash(fragments, optionsDiff);
-      }
       return hashCode;
     }