Earlier the atomicbitops_state_autogen.go was not being built because it had
an impossible build condition: `(amd64 || arm64) && !amd64 && !arm64`.
This is a known deficiency in go_stateify tool. This was solved via having
two identical files like 32b_32bit.go and 32b_64bit.go. Just piggyback this.
This changes also enhances `atomicbitops.Bool` in the following ways:
- Added RacyLoad(), RacyStore() and CompareAndSwap() for Bool to bring it up to
speed with the other types.
- Delegated the actual atomic operations work to the underlying Uint32.
- Cleaned up code with b32(); similar to what sync/atomic.Bool does.
PiperOrigin-RevId: 597607982
This adds a new atomic type, `atomicbitops.Float64`, which has similar
operations as `atomicbitops.Uint64`. It actually uses `atomicbitops.Uint64`
for storing its bits.
`atomicbitops.Float64` supports `Swap`, `CompareAndSwap`, and `Add`
operations.
This is useful in gVisor's metric library for keeping track of the
sum-of-squared-deviation statistic of distribution metrics.
PiperOrigin-RevId: 537127647
For all trivial and zero frame-sized functions, we now require an explicit
NOFRAME annotation as the heuristic has changed. See go.dev/cl/466316.
Most of these functions do not *require* NOFRAME, but this change encodes
the existing behavior in order to avoid accidental bugs or regressions.
PiperOrigin-RevId: 513946210
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
AlignedAtomicUint64 is 15 bytes and it takes 16 bytes in structures. On
32-bit systems, variables and structure fields is guaranteed to be
32-bit aligned and this means that we need only 12 bytes to find 8
contiguous bytes.
BP should be callee-save. It will be saved automatically if there is nonzero frame size.
$ go vet -framepointer ./pkg/atomicbitops
pkg/atomicbitops/atomicbitops_amd64.s:27:1: frame pointer is clobbered before saving
pkg/atomicbitops/atomicbitops_amd64.s:34:1: frame pointer is clobbered before saving
pkg/atomicbitops/atomicbitops_amd64.s:50:1: frame pointer is clobbered before saving
pkg/atomicbitops/atomicbitops_amd64.s:57:1: frame pointer is clobbered before saving
pkg/atomicbitops/atomicbitops_amd64.s:64:1: frame pointer is clobbered before saving
Signed-off-by: Koichi Shiraishi <zchee.io@gmail.com>
Ayush Ranjan
Etienne Perot
Adin Scannell
Nicolas Lacasse
gVisor bot
Brad Fitzpatrick
Kevin Krakauer
howard zhang
Brad Fitzpatrick
Koichi Shiraishi
Andrei Vagin
Jamie Liu