RFR: 8266252: Streamline AbstractInterpreter::method_kind

[Ioi Lam]

On Thu, 29 Apr 2021 16:04:54 GMT, Claes Redestad <redestad at openjdk.org> wrote:

> This patch refactors AbstractInterpreter::method_kind to reduce branches on average while better compartmentalizing the exceptional cases.
> 
> Additionally Method::is_empty_method is trivial enough that making it inlineable helps reduce cost while reducing size of the libjvm.
> 
> Result is a 40% speed-up, or a reduction of .25% of instructions on Hello World that scales to larger applications.

Looks good to me. Just a minor nit about asserts.

For other reviewers, you can get better diffs by adding `?w=1` to ignore whitespace changes. I.e., `https://github.com/openjdk/jdk/pull/3798/files?w=1`

src/hotspot/share/interpreter/abstractInterpreter.cpp line 143:

> 141:       // _dsqrt will be selected for both Math::sqrt and StrictMath::sqrt, but the latter
> 142:       // is native. Keep treating it like a native method in the interpreter
> 143:       case vmIntrinsics::_dsqrt: return m->is_native() ? native : java_lang_math_sqrt;

Maybe we should add an assert that m must be one of the two methods mentioned by the above comment?

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Marked as reviewed by iklam (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3798