Simplify tagged event handling.

Don't make copies of Events on replay. The same events may be replayed a lot,
so it's better to copy before storing the events. Also avoid a copy if the
tag doesn't actually change.

The intent of this change is to reduce gc churn on incremental builds. When
I wrote this change (~a year ago), this was a noticable source of gc churn in
some benchmarks I ran at the time.

PiperOrigin-RevId: 177450696

1 files changed, 1 insertions, 2 deletions

diff --git a/src/main/java/com/google/devtools/build/skyframe/ParallelEvaluatorContext.java b/src/main/java/com/google/devtools/build/skyframe/ParallelEvaluatorContext.java
index 840b5801e4..6860433c01 100644
--- a/src/main/java/com/google/devtools/build/skyframe/ParallelEvaluatorContext.java
+++ b/src/main/java/com/google/devtools/build/skyframe/ParallelEvaluatorContext.java
@@ -231,9 +231,8 @@ class ParallelEvaluatorContext {
 
     @Override
     public void accept(TaggedEvents events) {
-      String tag = events.getTag();
       for (Event e : events.getEvents()) {
-        reporter.handle(e.withTag(tag));
+        reporter.handle(e);
       }
     }
   }