Also adds the "// +checkalignedignore" escape hatch for packages to opt out of
checking.
See cl/439349432 for justification (https://github.com/google/gvisor/pull/7376).
PiperOrigin-RevId: 444918125
Part of a series of changes that will end with prohibiting use of sync/atomic
(u)int32 functions. See cl/440484071 for more details.
PiperOrigin-RevId: 442673296
All atomic 64 bit ints are changed to atomicbitops.(Ui|I)nt64. A nogo checker
enforces that sync/atomic 64 bit functions are not called.
For reviewers: the interesting changes are in the atomicbitops and checkaligned
packages.
Why do this?
- It is very easy to accidentally use atomic values without sync/atomic funcs.
- We have checkatomics, but this is optional and is forgotten in several places.
- Using a type+checker to enforce this seems less error prone and simpler.
- We get NoCopy protection.
- Use of 64 bit atomics can break 32 bit builds. We have types to handle this
without any runtime cost, so we might as well use them.
PiperOrigin-RevId: 440473398
- Redocument memory ordering from "no ordering" to "acquire-release". (No
functional change: both LOCK WHATEVER on x86, and LDAXR/STLXR loops on ARM64,
already have this property.)
- Remove IncUnlessZeroInt32 and DecUnlessOneInt32, which were only faster than
the equivalent loops using sync/atomic before the Go compiler inlined
non-unsafe.Pointer atomics many releases ago.
PiperOrigin-RevId: 295811743
Kevin Krakauer
Jamie Liu
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