768598 - add support for saving LR register

Status: RESOLVED FIXED

(Core :: Gecko Profiler, defect)

Description

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Attachment: Save ARM LR register in profiles

This is a hacky stopgap until we get full stack walking support.  We save the LR register with every PC sample, and then in the profiler UI we trust LR only from a set of whitelisted functions (mainly leaf functions from libc/bionic, e.g. various sycalls).  This gives us a bit of a better idea what's being called, even if we don't have the full stack.

Comment 1

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Attachment: Save ARM LR register in profiles

Missing #ifdefs around saving ->lr

Comment 2

[Benoit Girard (:BenWa)]

Comment on attachment 636837 [details] [diff] [review]
Save ARM LR register in profiles

r+ with the ifdef fixed to only add the L labels if we're coming from platform-linux so we don't trigger this on say windows arm.

Comment 3

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

On inbound as 2e9813915a1b

Comment 4

[(no longer active)]

https://hg.mozilla.org/mozilla-central/rev/2e9813915a1b