On Tue, 10 Nov 2020 07:22:07 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
>> 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 when >> working on this patch: removing this optimization yields 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 > > Aleksey Shipilev has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains six commits: > > - Simplify a few JVMTI_ENABLED blocks > - Merge branch 'master' into JDK-8255822-zero-jvmti-rework > - Fix build error > - Merge branch 'master' into JDK-8255822-zero-jvmti-rework > - Revert one dubious change > - 8255822: Zero: improve build-time JVMTI handling > Summary: use C++ templates instead of XSLT transforms Still good. ------------- Marked as reviewed by dholmes (Reviewer). PR: https://git.openjdk.java.net/jdk/pull/1061
