Unprotected reads -> relaxed reads.
Unprotected write -> relaxed write.
The only unprotected write we had was in SkTraceEvent, which it looks like we nabbed from Chrome at some point and changed only to silence TSAN. Chrome's version uses AtomicWord / NoBarrier_Load / NoBarrier_Store, which boils down to the same as here, intptr_t / relaxed load / relaxed store.
This leaves one place where we're lying a bit to TSAN, in include/core/SkLazyPtr.h where we're doing a data-dependent consume load. We're telling TSAN it's consume, but telling any other compiler to compile it as relaxed, given how they all upgrade consume to acquire. This eliminates a barrier for us on ARM. How do you guys deal with this? Just use a consume memory order, take the hit, and hope compilers get smarter one day?
BUG=chromium:465721
No public API changes.
TBR=reed@google.com
Review URL: https://codereview.chromium.org/996763002
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