RFR: JDK-8314890: Reduce number of loads for Klass decoding in static code [v4]

[Thomas Stuefe]

On Mon, 4 Sep 2023 09:28:10 GMT, Andrew Haley <aph at openjdk.org> wrote:

> So, I was wondering if there is there some reason to do all this manually? It looks like an obvious candidate for bitfields.

The immediate reason is that a static class member cannot be a bitfield. Another reason is that bitfields are not used much in hotspot, manual bitfiddling is the way things are done (see for instance markword element handling). The only cases where bitfields are used seem to be in interface headers used from outside the hotspot, e.g. jmm.hpp.

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PR Comment: https://git.openjdk.org/jdk/pull/15389#issuecomment-1746379706