On Thu, 18 Apr 2024 20:11:15 GMT, Claes Redestad <[email protected]> wrote:
> Investigating a recent regression in mainline I realized we have an
> opportunity to improve the bootstrap overheads of ObjectMethods::bootstrap by
> using `invokeExact` in a way similar to what we already do for LMF and SCF
> BSMs. This avoids generating type checking adapters and equates to a one-off
> startup win of around 5ms in any app that ever has the need to spin up a
> toString, equals or hashCode method on a record.
src/java.base/share/classes/java/lang/invoke/BootstrapMethodInvoker.java line
150:
> 148: } else if (isObjectMethodsBootstrapBSM(bsmType)) {
> 149: MethodHandle[] methodHandles = new
> MethodHandle[argv.length - 2];
> 150: System.arraycopy(argv, 2, methodHandles, 0,
> argv.length - 2);
Are we avoiding `Arrays.copyOfRange(argv, 2, argv.length, MethodHandle.class)`
because of the JIT? If JIT compiler can recognize `MethodHandle.class` constant
and inline I recommend using copyOfRange like for string concat above.
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PR Review Comment: https://git.openjdk.org/jdk/pull/18845#discussion_r1571783566
