RFR: 8008243: Zero: Implement fast bytecodes

Aleksey Shipilev shade at openjdk.java.net
Mon Oct 18 14:47:04 UTC 2021

This work improves Zero performance considerably, without complicating the interpreter all that much. This work is based on much earlier patch by @rkennke, then edited by @jerboaa, and finally polished by me here :)

SPECjvm benchmarks improve across the board, with lowest improvement on `Derby` (+6%) and largest on `Compress` (+50%). Given that Zero is used to implement the JVM on emerging platforms that are still rather slow themselves, it makes sense to make Zero quantifiably faster. Even 10% improvement means more than 2 hours a day worth of CPU time.

Additional testing:
 - [x] Linux x86_64 Zero fastdebug bootcycle-images
 - [x] Linux x86_64 Zero fastdebug fuzzer tests (no failures = no new behaviors introduced)


Commit messages:
 - Base implementation

Changes: https://git.openjdk.java.net/jdk/pull/1938/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1938&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8008243
  Stats: 576 lines in 1 file changed: 505 ins; 57 del; 14 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1938.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1938/head:pull/1938

PR: https://git.openjdk.java.net/jdk/pull/1938

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