Optimize the hash code function of Pair to minimize varargs expansion.

--
MOS_MIGRATED_REVID=107812527

2 files changed, 4 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/util/Pair.java b/src/main/java/com/google/devtools/build/lib/util/Pair.java
index 08f1e798f0..91d04c62f1 100644
--- a/src/main/java/com/google/devtools/build/lib/util/Pair.java
+++ b/src/main/java/com/google/devtools/build/lib/util/Pair.java
@@ -81,7 +81,9 @@ public final class Pair<A, B> {
 
   @Override
   public int hashCode() {
-    return Objects.hash(first, second);
+    int hash1 = first == null ? 0 : first.hashCode();
+    int hash2 = second == null ? 0 : second.hashCode();
+    return 31 * hash1 + hash2;
   }
 
   /**
diff --git a/src/test/java/com/google/devtools/build/lib/util/PairTest.java b/src/test/java/com/google/devtools/build/lib/util/PairTest.java
index a54b256da5..98bebbc867 100644
--- a/src/test/java/com/google/devtools/build/lib/util/PairTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/PairTest.java
@@ -21,8 +21,6 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
-import java.util.Objects;
-
 /**
  * Tests for {@link Pair}.
  */
@@ -37,7 +35,7 @@ public class PairTest {
     assertSame(a, p.first);
     assertSame(b, p.second);
     assertEquals(Pair.of(a, b), p);
-    assertEquals(Objects.hash(a, b), p.hashCode());
+    assertEquals(31 * a.hashCode() + b.hashCode(), p.hashCode());
   }
 
   @Test