Right now flamegraph uses dtrace on macOS but this runs into some limitations:

• Inline frames are not properly handled (Incorrect or partial flamegraph output on MacOS #113)
• Running dtrace requires root rights
• dtrace is generally considered deprecated functionality on macOS and will likely disappear longer term

One potential solution is to switch to xctrace and then implement a reader for the .trace / .run files. speedscope appears to have partial support for these files but I haven't been able to make it work at all yet. There is an issue from a while ago that it's not working (jlfwong/speedscope#196) but the code there might still be useful.