Current Zero interpreter has the optimization for JVMTI support. It recognizes that JVMTI is disabled most of the time, and that JVMTI checks in the interpreter code slows it down considerably. (I measured it myself for this patch, it gives about 20% hit in build times).
Current optimization works as follows. At build time, an XSLT transform is performed on `bytecodeInterpreter.cpp`, yielding `bytecodeInterpreterWithChecks.cpp`. In that new compilation unit, `VM_JVMTI` macro is defined, and a new entry point -- `BytecodeInterpreter::withChecks` -- is defined. Then, both compilation units are compiled. In one of them, `JVMTI` hooks are stripped out. In another, they persist. Then, callers have to choose which entry point to use. I believe this can be rewritten to use C++ templates instead of XLST and defines dance. This also allows to clean up JVMTI checks a bit. Additional testing: - [x] Linux x86_64 Zero fastdebug build with `-jvmti` - [x] Linux x86_64 Zero fastdebug/release build times are not regressing ------------- Commit messages: - Revert one dubious change - 8255822: Zero: improve build-time JVMTI handling Changes: https://git.openjdk.java.net/jdk/pull/1061/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1061&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8255822 Stats: 155 lines in 6 files changed: 3 ins; 118 del; 34 mod Patch: https://git.openjdk.java.net/jdk/pull/1061.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/1061/head:pull/1061 PR: https://git.openjdk.java.net/jdk/pull/1061
