RFR: 8200238: Reduce number of exceptions created when calling MemberName$Factory::resolveOrNull
claes.redestad at oracle.com
Mon Mar 26 12:08:06 UTC 2018
MethodHandleNatives::resolve are used by both
MemberName$Factory::resolveOrFail and ::resolveOrNull, the latter
allowing speculative lookup of methods.
While the linkResolver code this calls into in the VM will create and
throw exceptions for all cases where a method or field is missing, these
are caught by MethodHandles::resolve_MemberName and an empty handle is
returned instead. However, the outer method, MHN_resolve_Mem will always
create a new exception and throw it.
In case of resolveOrNull, we'll then ignore whatever exception is thrown
in the java code, so in effect we're creating and ignoring two
exceptions on a failed lookup.
We can cut this in half by passing a boolean to
MethodHandleNatives::resolve to indicate whether we're doing a
speculative lookup (resolveOrNull) or not (resolveOrFail):
This is a small startup optimization for applications that have a high
miss rate (looks up a lot of methods that doesn't exist in the
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