See golang.org/s/go12encoding for design.

R=r
CC=golang-dev
https://golang.org/cl/12541051

See golang.org/s/go12xml for design.

Fixes #2771.
Fixes #4169.
Fixes #5975.
Fixes #6125.

R=golang-dev, iant, dan.kortschak
CC=golang-dev
https://golang.org/cl/12603044

Fixes #5789.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10601043

Fixes #5126.

R=golang-dev, dsymonds, bradfitz, r, rsc, rogpeppe
CC=golang-dev
https://golang.org/cl/12566046

Do not use ? :
I cannot say this enough.

TBR=dvyukov
CC=golang-dev
https://golang.org/cl/12903043

Accessor to find where the bytes of a file start.

R=golang-dev, rsc, dsymonds, adg
CC=golang-dev
https://golang.org/cl/12784045

Update #4856

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12763044

Update #6081

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/12810043

Update #6138

TestOver65kFiles spends all its time garbage collecting.
Removing the 1.4 MB of allocations per each of the 65k
files brings this from 34 seconds to 0.23 seconds.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12894043

Use the fast path calculation to shorten the code.
No effect on benchmarks.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12696046

Before,
        go test -bench .
would just dump the long generic "go help" message. Confusing and
unhelpful. Now the message is short and on point and also reminds the
user about the oft-forgotten "go help testflag".

        % go test -bench
        go test: missing argument for flag bench
        run "go help test" or "go help testflag" for more information
        %

R=rsc
CC=golang-dev
https://golang.org/cl/12662046

Now builders say:
pkg/net/dnsclient_unix_test.go:10: imported and not used: "runtime"

R=golang-dev
CC=golang-dev
https://golang.org/cl/12890043

Windows builders say:
pkg\net\dnsclient_unix_test.go:24: undefined: dnsConfig
pkg\net\dnsclient_unix_test.go:25: undefined: exchange

R=golang-dev
CC=golang-dev
https://golang.org/cl/12889043

The schedtrace value sets dump period in milliseconds.
In default mode the trace looks as follows:
SCHED 0ms: gomaxprocs=4 idleprocs=0 threads=3 idlethreads=0 runqueue=0 [1 0 0 0]
SCHED 1001ms: gomaxprocs=4 idleprocs=3 threads=6 idlethreads=3 runqueue=0 [0 0 0 0]
SCHED 2008ms: gomaxprocs=4 idleprocs=1 threads=6 idlethreads=1 runqueue=0 [0 1 0 0]
If GODEBUG=scheddetail=1 is set as well, then the detailed trace is printed:
SCHED 0ms: gomaxprocs=4 idleprocs=0 threads=3 idlethreads=0 runqueue=0 singleproc=0 gcwaiting=1 mlocked=0 nmspinning=0 stopwait=0 sysmonwait=0
  P0: status=3 tick=1 m=0 runqsize=1/128 gfreecnt=0
  P1: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0
  P2: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0
  P3: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0
  M2: p=-1 curg=-1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=-1
  M1: p=-1 curg=-1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=-1
  M0: p=0 curg=1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=1
  G1: status=2() m=0 lockedm=0
  G2: status=1() m=-1 lockedm=-1

R=golang-dev, raggi, rsc
CC=golang-dev
https://golang.org/cl/11435044

They don't work on older chips, just like the x86-32 64-bit atomics.

Update #6134

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12880043

Breaks the build.  Old bucket arrays kept by iterators
still need to be scanned.

««« original CL description
runtime: tell GC not to scan internal hashmap structures.
We'll do it ourselves via hash_gciter, thanks.
Fixes bug 6119.

R=golang-dev, dvyukov, cookieo9, rsc
CC=golang-dev
https://golang.org/cl/12840043
»»»

R=golang-dev
CC=golang-dev
https://golang.org/cl/12884043

We'll do it ourselves via hash_gciter, thanks.
Fixes bug 6119.

R=golang-dev, dvyukov, cookieo9, rsc
CC=golang-dev
https://golang.org/cl/12840043

The NetBSD and OpenBSD failures are apparently real,
not due to the test bug fixed in 100b9fc0c46f.

««« original CL description
runtime/pprof: test netbsd and openbsd again

Maybe these will work now.

R=golang-dev, dvyukov, bradfitz
CC=golang-dev
https://golang.org/cl/12787044
»»»

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12873043

Fixes #6100.

R=golang-dev, dave, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/12703045

Currently it's possible that a goroutine
that periodically executes non-blocking
cgo/syscalls is never preempted.
This change splits scheduler and syscall
ticks to prevent such situation.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12658045

Currently we lose lots of profiling signals.
Most notably, GC is not accounted at all.
But stack splits, scheduler, syscalls, etc are lost as well.
This creates seriously misleading profile.
With this change all profiling signals are accounted.
Now I see these additional entries that were previously absent:
161  29.7%  29.7%      164  30.3% syscall.Syscall
 12   2.2%  50.9%       12   2.2% scanblock
 11   2.0%  55.0%       11   2.0% markonly
 10   1.8%  58.9%       10   1.8% sweepspan
  2   0.4%  85.8%        2   0.4% runtime.newstack
It is still impossible to understand what causes stack splits,
but at least it's clear how many time is spent on them.
Update #2197.
Update #5659.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12179043

Fixes #6070.
Update #6055.

R=golang-dev, nightlyone, rsc
CC=golang-dev
https://golang.org/cl/12602043

R=cshapiro
CC=golang-dev
https://golang.org/cl/12877043

Return an ErrClosedPipe rather than allowing the write to proceed.

Fixes #5330.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12541053

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12870043

so that we don't need to traceback through __kuser_cmpxchg

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12869043

Fixes #5686.

R=golang-dev, bradfitz, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/12458043

* Add a new kind of Name, "fpvar" which stands for function pointer variable
* When walking the AST, find functions used as expressions and create a new Name object for them
* Track functions which are only used in expr contexts, and avoid generating bridge code for them

R=golang-dev, minux.ma, fullung, rsc, iant
CC=golang-dev
https://golang.org/cl/9835047

Maybe these will work now.

R=golang-dev, dvyukov, bradfitz
CC=golang-dev
https://golang.org/cl/12787044

R=bradfitz, dave, rsc, r
CC=golang-dev
https://golang.org/cl/10001045

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/12790043

Ensure that deadlines affect already issued IO.

R=golang-dev, mikioh.mikioh, bradfitz
CC=golang-dev
https://golang.org/cl/12847043

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12851043

Fixes #5722.

R=golang-dev, khr, cshapiro, rsc, r
CC=golang-dev
https://golang.org/cl/12670045

Just for readability reasons; to prevent overlooking deadline stuff
across over platforms.

R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/8656044

The new version does not require any memory allocations and is 30-50% faster.
Also detect and painc if Cond is copied after first.

benchmark            old ns/op    new ns/op    delta
BenchmarkCond1             317          195  -38.49%
BenchmarkCond1-2           875          607  -30.63%
BenchmarkCond1-4          1116          548  -50.90%
BenchmarkCond1-8          1013          613  -39.49%
BenchmarkCond1-16          983          450  -54.22%
BenchmarkCond2             559          352  -37.03%
BenchmarkCond2-2          1916         1378  -28.08%
BenchmarkCond2-4          1518         1322  -12.91%
BenchmarkCond2-8          2313         1291  -44.19%
BenchmarkCond2-16         1885         1078  -42.81%
BenchmarkCond4            1070          614  -42.62%
BenchmarkCond4-2          4899         3047  -37.80%
BenchmarkCond4-4          3813         3006  -21.16%
BenchmarkCond4-8          3605         3045  -15.53%
BenchmarkCond4-16         4148         2637  -36.43%
BenchmarkCond8            2086         1264  -39.41%
BenchmarkCond8-2          9961         6736  -32.38%
BenchmarkCond8-4          8135         7689   -5.48%
BenchmarkCond8-8          9623         7517  -21.89%
BenchmarkCond8-16        11661         8093  -30.60%

R=sougou, rsc, bradfitz, r
CC=golang-dev
https://golang.org/cl/11573043

If the timer goroutine is wakeup by timeout,
other goroutines will still notewakeup because sleeping is still set.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12763043

Fixes #5517.
Fixes #5659.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12183044

Fixes #6103.

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/12686045

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/12836044