1407662 - Provide information on JIT code region in profile

Status: RESOLVED DUPLICATE of bug 1426124

(Core :: Gecko Profiler, enhancement)

Description

[(not currently active) Ted Mielczarek]

perf-html would like to be able to hide or at least annotate JIT frames, because they currently just show up as bare addresses:
https://github.com/devtools-html/perf.html/issues/586

There's already an API that the JIT uses to provide info about JIT code regions, it's used by the stackwalker code on 64-bit platforms:
https://dxr.mozilla.org/mozilla-central/rev/19b32a138d08f73961df878a29de6f0aad441683/mozglue/misc/StackWalk.cpp#137

We could enable that code on all platforms (it's only called when the JIT code region changes) and save that information in profiles so that perf-html could annotate the JIT frames as such, or hide them.

Comment 1

[Greg Tatum [:gregtatum]]

I believe there Bug 1426124 solved this problem, and we already get some JIT information around the JIT optimizations. It's not clear to me (I'm no JS engine expert) on how RegisterJitCodeRegion would help us out at this point. If I'm missing something feel free to chime in and I can re-open this, but for now I'm marking it as a duplicate.

Comment 2

[(not currently active) Ted Mielczarek]

For profiling purposes filtering those frames is probably fine, no worries!