mbeckerle commented on a change in pull request #316: Assortment of changes to
improve performance
URL: https://github.com/apache/incubator-daffodil/pull/316#discussion_r370336336
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File path:
daffodil-runtime1/src/main/scala/org/apache/daffodil/processors/Evaluatable.scala
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@@ -285,7 +285,17 @@ abstract class Evaluatable[+T <: AnyRef](protected val
ci: DPathCompileInfo, qNa
/**
* Preferred for use in the runtime.
*/
- @inline final def maybeConstant = constValue_.asInstanceOf[Maybe[T]]
+ @inline final def maybeConstant = {
+ // We could just do constValue_.asInstanceOf[Maybe[T]], but the compiled
+ // bytecode ends up allocating a Maybe. Since constant values are accessed
+ // very often, we really want to avoid that overhead. The following gets
+ // rid of those unnecessary allocations.
+ if (constValue_.isDefined) {
+ Maybe[T](constValue_.get.asInstanceOf[T])
Review comment:
This is interesting. So yeah, if you return constValue_ and cast it, that's
a generic operation, which requires a boxed object.
We should consider if this can be caught somehow. At minimum we can search
for "asInstanceOf[Maybe" and see if any others come up.
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