RFR: 8323183: ClassFile API performance improvements

[Adam Sotona]

On Mon, 8 Jan 2024 14:43:58 GMT, Chen Liang <liach at openjdk.org> wrote:

> You need to update the slot counting from `DirectCodeBuilder` and `StackMapDecoder` to fully avoid creating any MethodTypeDesc.

It would be good to avoid all bottlenecks, however not all of them have equal effect.
This patch avoids MTD construction for every invocation instruction. We may cache the symbol in the relevant Utf8Entry, however it still means to create each MTD at least once. "Hairy" methods doing a lot of various invocations are the most affected.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/17306#issuecomment-1881429589