Profiler does not work on ruby-head (3.3.0dev)

[ivoanjo]

Current behaviour:

When trying to enable profiling on ruby-head (3.3.0dev), it refuses to turn on with this message:

W, [2023-03-10T18:09:50.702665 #912154] WARN -- ddtrace: [ddtrace] Profiling was requested but is not supported, profiling disabled: Your ddtrace installation is missing support for the Continuous Profiler because your Ruby has been compiled without JIT support (--disable-jit-support). The profiling native extension requires a Ruby compiled with JIT support, even if the JIT is not in use by the application itself. For help solving this issue, please contact Datadog support at <https://docs.datadoghq.com/help/>. You can also check out the Continuous Profiler troubleshooting page at <https://dtdg.co/ruby-profiler-troubleshooting>.

This is actually not the case; what happened is that the mjit header that we check for and were using has been obsoleted and dropped as of ruby/ruby#7458 .

(I plan to support Ruby 3.3 using the debase-ruby_core_source gem, which we're already using to support Ruby 2.5 and below. But currently this is not yet in place.)

Expected behaviour:

Profiler should run on Ruby 3.3 as well.

Steps to reproduce:

1. Try to profile ruby 3.3: DD_PROFILING_ENABLED=true be ddtracerb exec ruby -e sleep
2. It fails

Environment

• ddtrace version: master
• Configuration block (Datadog.configure ...): -
• Ruby version: 3.3
• Operating system: -
• Relevant library versions: -

[ivoanjo]

Fixed in #2860