On Wed, 17 Jul 2024 04:52:35 GMT, David Holmes <dhol...@openjdk.org> wrote:
>> Citing David Holmes from bug report: >> "We provided the ability to leave out certain VM services (JVMTI, GC's other >> than serial, ...) as part of the design of the MinimalVM to support Java SE >> Embedded, along with the Compact Profiles of JDK 8. This manifested in the >> source code as a set of INCLUDE_XXX ifdef guards. The build system later >> exposed these as individual --with-jvm-features=xxx,yyy support. However, it >> was never intended (and certainly not tested) that you could mix-and-match >> arbitrary subsets of these VM features at will. Consequently if you start >> trying to do this you will find things that need fixing." >> >> I added `INCLUDE_JVMTI` guards in two places where it was missed: JVMCI and >> JFR. Affected code was added recently, in the past year. After that I was >> able to build VM on all supported platforms. >> >> Note: building VM without JVMTI is not officially supported feature. We are >> not testing it and such failures (missing guards) are not unexpected. >> >> A lot of tests failed with VM without JVMTI. All are expected failures. I >> listed failed tests in bug report. >> I fixed (added requires `vm.jvmti`) only one which was part of >> [JDK-8257967](https://bugs.openjdk.org/browse/JDK-8257967) changes which >> introduced JFR code without `INCLUDE_JVMTI` guards. >> >> I ran 2 rounds of testing: >> >> First, only **tier1** with VM built without JVMTI to see if builds passed >> and which tests affected. I wrote comment in bug report which tests failed >> (all expected to fail without JVMTI). >> >> Second round of testing with JVMTI in VM: tier1-4 > > src/hotspot/share/jfr/instrumentation/jfrJvmtiAgent.hpp line 35: > >> 33: JfrJvmtiAgent(); >> 34: ~JfrJvmtiAgent(); >> 35: static bool create() NOT_JVMTI_RETURN_(true); > > It initially seemed odd to return `true` here, but looking through the JFR > code that interacts with the Agent it seems the right way to view this is > that without JVMTI we have a no-op agent. Right. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/20209#discussion_r1680433885
