Add user_events support for the native runtime events

[davmason]

Opening as a draft because there are still build errors, but I wanted to give people a chance to look at the shape of the changes. This adds support to the runtime to emit events under the user_events format, using the EventHeader format described at https://github.com/microsoft/LinuxTracepoints/.

[davmason]

I believe all the build issues are sorted now, and the LinuxTracepoints code is moved to the appropriate place (src/native/external) so marking this as ready to review. @noahfalk @brianrob if you could take a look I would appreciate it.

Since the generated files aren't part of the code review I will paste examples here.

clretwallmain.h is modified to generate user_events support on linux

inline BOOL EventEnabledGCStart(void) {return EventPipeEventEnabledGCStart() || UserEventsEventEnabledGCStart() || (XplatEventLogger::IsEventLoggingEnabled() && EventXplatEnabledGCStart());}

inline ULONG FireEtwGCStart(
    const unsigned int  Count,
    const unsigned int  Reason,
    LPCGUID ActivityId = nullptr,
    LPCGUID RelatedActivityId = nullptr
)
{
    ULONG status = EventPipeWriteEventGCStart(Count,Reason,ActivityId,RelatedActivityId);
status &= UserEventsWriteEventGCStart(Count,Reason,ActivityId,RelatedActivityId);
    status &= FireEtXplatGCStart(Count,Reason);
    return status;
}

Each provider has a separate file, following the custom of EventPipe. The files declare the provider and then add a UserEventsEventEnabled* and UserEventsWrite* like the following:

TRACELOGGING_DEFINE_PROVIDER(DotNETRuntime, "Microsoft-Windows-DotNETRuntime", (0xe13c0d23, 0xccbc, 0x4e12, 0x93, 0x1b, 0xd9, 0xcc, 0x2e, 0xee, 0x27, 0xe4));

BOOL UserEventsEventEnabledGCStart(void)
{
    return IsUserEventsEnabled() && TraceLoggingProviderEnabled(UserEventGCStart, 4, 1);
}

extern "C" ULONG UserEventsWriteEventGCStart(
    const unsigned int Count,
    const unsigned int Reason,
    LPCGUID ActivityId,
    LPCGUID RelatedActivityId)
{
    if (!UserEventsEventEnabledGCStart())
        return ERROR_SUCCESS;
    TraceLoggingWriteActivity(DotNETRuntime, "GCStart", ActivityId, RelatedActivityId, TraceLoggingLevel(4), TraceLoggingKeyword(1),
    TraceLoggingUInt32(Count),
    TraceLoggingUInt32(Reason)
    );
    return ERROR_SUCCESS;
}

[AaronRobinsonMSFT]

@jkoritzinsky Any concerns with the CMake here?

[noahfalk]

A few small comments/questions inline, but the main request I'd have is please add at least a brief document in docs/design/features :)

It should describe what functionality is being added, how to turn it on, what is the format of the data in the events, the current state of the feature (ie no EventSource support, no TraceEvent support), what Linux environment is needed for it to work, and a pointer to relevant code/docs/important comments for those wanting to learn more.

[noahfalk]

Since the generated files aren't part of the code review I will paste examples here.

Can you add those examples in the design doc and/or as comments in the python code. They are very useful to understand the feature not just now but when someone is trying to learn about it in the future.

[davmason]

Can you add those examples in the design doc and/or as comments in the python code. They are very useful to understand the feature not just now but when someone is trying to learn about it in the future.

Sure thing, just pushed a design doc and some more comments in genUserEvents.py

[davmason]

@noahfalk I just pushed a new commit that makes it so user_events can be checked by category, not just event. Can you take a look and make sure you're ok with the additional changes?