On Wed, 18 Oct 2023 11:56:14 GMT, Claes Redestad <redes...@openjdk.org> wrote:
> In #16006 using `StringConcatFactory` seem to induce a run-to-run variance.
> One idea to reduce this is to generate expression trees with fewer branches
> by looking up and using the prefix-less `prepend` methods directly for cases
> where constant is null/empty so that the prefixed prepender will always deal
> with a non-null prefix constant.
src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java line 725:
> 723: }
> 724:
> 725: private static MethodHandle noPrefixPrepender(Class<?> cl) {
Should the no-prefix prependers be declared package-private now that they are
accessed via JLA? Otherwise we might accidentally change those APIs and break
stuff.
Another way to guard is to make stringConcatHelper find methods with a lookup
restricted to package access by changing this line:
https://github.com/openjdk/jdk/blob/e25a49a993f270c33f7929e629fb3075a11fdec9/src/java.base/share/classes/java/lang/StringConcatHelper.java#L589
to
return MethodHandles.lookup()
.dropLookupMode(MethodHandles.Lookup.PRIVATE)
.findStatic(StringConcatHelper.class, name, methodType);
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/16244#discussion_r1364794177
