Depending on net/http means depending on cgo.
When the tree is in a shaky state it's nice to see sync/atomic
pass even if cgo or net causes broken binaries.
R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/10753044
Currently more than 1 gorutine can execute raceWrite() in Wait()
in the following scenario:
1. goroutine 1 executes first check of wg.counter, sees that it's == 0
2. goroutine 2 executes first check of wg.counter, sees that it's == 0
3. goroutine 2 locks the mutex, sees that he is the first waiter and executes raceWrite()
4. goroutine 2 block on the semaphore
5. goroutine 3 executes Done() and unblocks goroutine 2
6. goroutine 1 lock the mutex, sees that he is the first waiter and executes raceWrite()
It produces the following false report:
WARNING: DATA RACE
Write by goroutine 35:
sync.raceWrite()
src/pkg/sync/race.go:41 +0x33
sync.(*WaitGroup).Wait()
src/pkg/sync/waitgroup.go:103 +0xae
command-line-arguments_test.TestNoRaceWaitGroupMultipleWait2()
src/pkg/runtime/race/testdata/waitgroup_test.go:156 +0x19a
testing.tRunner()
src/pkg/testing/testing.go:361 +0x108
Previous write by goroutine 36:
sync.raceWrite()
src/pkg/sync/race.go:41 +0x33
sync.(*WaitGroup).Wait()
src/pkg/sync/waitgroup.go:103 +0xae
command-line-arguments_test.func·012()
src/pkg/runtime/race/testdata/waitgroup_test.go:148 +0x4d
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10424043
Do not synchronize Add(1) with Wait().
Imitate read on first Add(1) and write on Wait(),
it allows to catch common misuses of WaitGroup:
- Add() called in the additional goroutine itself
- incorrect reuse of WaitGroup with multiple waiters
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/10093044
The race detector uses a global lock to analyze atomic
operations. A panic in the middle of the code leaves the
lock acquired.
Similarly, the sync package may leave the race detectro
inconsistent when methods are called on nil pointers.
R=golang-dev, r, minux.ma, dvyukov, rsc, adg
CC=golang-dev
https://golang.org/cl/7981043
And fix test. Pointer to unsafe.Pointer tests nothing important...
Also identify the incorrect type: go/types.Type is a Stringer.
Also fix a couple of incorrect format verbs found by new printf checker,
now that we can run it on more files.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7385051
deferred block. This makes hangs in the waiting code less likely
if a goroutine exits abnormally.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7306052
It allows to catch e.g. a data race between atomic write and non-atomic write,
or Mutex.Lock() and mutex overwrite (e.g. mu = Mutex{}).
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6817103
Rename the first argument of CompareAndSwapT and AddT s/val/addr/
for consistency with LoadT and StoreT.
R=rsc, r, dvyukov
CC=golang-dev
https://golang.org/cl/6494112
No perf/semantic changes, merely improves code health.
There were several questions as to why Once.Do uses
atomic.CompareAndSwap to do a store.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6208057
This is a follow-up to CL 5978051.
Use kernel cas64 helper if we can, fallback to LDREXD/STREXD if
we are on ARMv6 or higher, and to lock-emulated cas64 if on ARMv5.
A future CL will fix {Add,Load,Store}{Int,Uint}64 and issue 3331.
R=bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6034048
The docs look awkward - there is a paragraph
"For example:" with a plain text example,
and straight below it a real Example.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5717048
hammerCompareAndSwapPointer64 was only passing on
little-endian systems. hammerCompareAndSwapPointer32 was
writing 8 bytes to a uint32 value on the heap.
R=rsc, dvyukov
CC=golang-dev
https://golang.org/cl/5654065
Consequently, remove many package Makefiles,
and shorten the few that remain.
gomake becomes 'go tool make'.
Turn off test phases of run.bash that do not work,
flagged with $BROKEN. Future CLs will restore these,
but this seemed like a big enough CL already.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5601057
An experiment: allow structs to be copied even if they
contain unexported fields. This gives packages the
ability to return opaque values in their APIs, like reflect
does for reflect.Value but without the kludgy hacks reflect
resorts to.
In general, we trust programmers not to do silly things
like *x = *y on a package's struct pointers, just as we trust
programmers not to do unicode.Letter = unicode.Digit,
but packages that want a harder guarantee can introduce
an extra level of indirection, like in the changes to os.File
in this CL or by using an interface type.
All in one CL so that it can be rolled back more easily if
we decide this is a bad idea.
Originally discussed in March 2011.
https://groups.google.com/group/golang-dev/t/3f5d30938c7c45ef
R=golang-dev, adg, dvyukov, r, bradfitz, jan.mercl, gri
CC=golang-dev
https://golang.org/cl/5372095
MFENCE was introduced only on the Pentium4 (SSE2),
while XADD was introduced on the 486.
Fixes#2268.
R=golang-dev, rsc
CC=fshahriar, golang-dev
https://golang.org/cl/5056045
Disable the LoadInt32 and LoadUint32 tests, since they fail.
These should be fixed but we want to get through the rest of the build
to see if something else unrelated is broken. The arm build has been
bad for a long time.
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4780041
