Minor. Saw this in a profile at few percent of CPU and was
curious what it was. Improves overall regexp benchmarks
anywhere from 0 to 3%, but they're a pain to run. You need to
run them in isolation for long runs to get stable numbers.

benchmark                  old ns/op    new ns/op    delta
BenchmarkEmptyOpContext          537          473  -11.92%

R=golang-dev, crawshaw
CC=golang-dev
https://golang.org/cl/13407043

AES-GCM is the only current TLS ciphersuite that doesn't have
cryptographic weaknesses (RC4), nor major construction issues (CBC mode
ciphers) and has some deployment (i.e. not-CCM).

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13249044

I noticed that this one benchmark in particular was very
noisy.  Looking into it, I saw that the table was wrong
and inconsistent with the lines above and below.

R=golang-dev, crawshaw
CC=golang-dev
https://golang.org/cl/13393045

R=bradfitz, alberto.garcia.hierro, rsc, adg
CC=golang-dev
https://golang.org/cl/7099045

When searching for an allocated bit, flushptrbuf would search
backward in the bitmap word containing the bit of pointer
being looked-up before searching the span.  This extra check
was not replicated in markonly which, instead, after not
finding an allocated bit for a pointer would directly look in
the span.

Using statistics generated from godoc, before this change span
lookups were, on average, more common than word lookups.  It
was common for markonly to consult spans for one third of its
pointer lookups.  With this change in place, what were
previously span lookups are overwhelmingly become by the word
lookups making the total number of span lookups a relatively
small fraction of the whole.

This change also introduces some statistics gathering about
lookups guarded by the CollectStats enum.

R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/13311043

#pragma textflag and #pragma dataflag directives.
Update dataflag directives to use symbols instead of integer constants.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13310043

Fixes #6138.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12953048

Fixes #5378

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/13247044

Types in function scope can have methods on them if they embed another type, but we didn't make the name unique, meaning that 2 identically named types in different functions would conflict with eachother.

Fixes #6269.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13326045

These instructions are emitted when GO386=387 or the target
i386 CPU does not have SSE2 capabilities.

Fixes #6215.

R=golang-dev, remyoudompheng
CC=golang-dev
https://golang.org/cl/12812045

The compiler computes initialization order by finding
a spanning tree between a package's global variables.
But it does so by walking both variables and functions
and stops detecting cycles between variables when they
mix with a cycle of mutually recursive functions.

Fixes #4847.

R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/9663047

Fixes #6140.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/13083043

Thanks to beatgammit for the fix.

Fixes #5408.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13261048

R=r, dvyukov
CC=golang-dev
https://golang.org/cl/13348045

Accidentally submitted.

««« original CL description
encoding/json: add "overflow" struct tag option

Fixes #6213.

R=golang-dev, dsymonds, bradfitz
CC=golang-dev
https://golang.org/cl/13180043
»»»

R=golang-dev
CC=golang-dev
https://golang.org/cl/13234045

Before this fix, it was always an error to use the Close method on the
io.WriteCloser obtained from Cmd.StdinPipe, as it would race with the
Close performed by Cmd.Wait.

Fixes #6270.

R=golang-dev, r, remyoudompheng, bradfitz, dsymonds
CC=golang-dev
https://golang.org/cl/13329043

Fixes #6213.

R=golang-dev, dsymonds, bradfitz
CC=golang-dev
https://golang.org/cl/13180043

Adapted from https://golang.org/cl/11564044.

Fixes breakage of darwin-amd64-race builder.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/13352045

See how it flies. We'll disable it again if the underlying issue is not resolved.
See issue 4155 for details.

Fixes #4155.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13368045

Update #4856

R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/12916046

Fixes #3944.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/13263043

Causes the package dependencies to include those for race detection.
Fixes #5653.

R=golang-dev, dave, bradfitz
CC=golang-dev
https://golang.org/cl/13236045

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/13334043

R=golang-dev, remyoudompheng
CC=golang-dev
https://golang.org/cl/12795052

Merge the comment from runtime/time.goc ("at least")
and also note that negative is okay and won't crash.
I see people going out of their way to avoid passing
a negative value to Sleep.

R=golang-dev, adg, r, alex.brainman
CC=golang-dev
https://golang.org/cl/13271045

The method is simple: the parser just parses

        {{if A}}a{{else if B}}b{{end}}

to the same tree that would be produced by

        {{if A}}a{{else}}{{if B}}b{{end}}{{end}}

Thus no changes are required in text/template itself
or in html/template, only in text/template/parse.

Fixes #6085

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/13327043

The previous wording, though accurate, was hard to parse.
In particular, it was tempting to interpret "the method"
as referring to "the function f" instead of "Do", and
required effort to find the correct antecedent for
"this receiver".

R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/13307043

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13313043

Fixes #6221

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/13289043

It wasn't obvious that the Auth could be nil.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/13060048

Fixes #5910.
Fixes #6260.

R=golang-dev, daniel.morsing
CC=golang-dev
https://golang.org/cl/13257044

Fixes #6247.

R=golang-dev, lucio.dere, bradfitz
CC=golang-dev
https://golang.org/cl/13216043

Removed posix assumptions in temporary file generation
Removed curl dependence
Changed opening of svg file

These must now work including symbol resolution.
[1] go tool pprof <prog_name> http://.../debug/pprof/profile
[2] go tool pprof http://.../debug/pprof/profile

Fixes 6177.

R=golang-dev, alex.brainman, bradfitz, kamil.kisiel
CC=golang-dev
https://golang.org/cl/13085043

A bullet list was getting mangled in godoc.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13060047

Reduce the number of allowed swap operations during stable sort. 

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12907045

Some users have multiple Go development trees and invoke the
'go' tool via a wrapper that sets GOROOT and GOPATH based on
the current directory.  Such users should customize go-command
to point to the wrapper script.

R=dominik.honnef
CC=golang-dev
https://golang.org/cl/13233043

No measurable impact on performance on amd64

R=golang-dev, khr, bradfitz
CC=golang-dev
https://golang.org/cl/13096045

R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/13274043

Fixes #4195

R=golang-dev, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/12960046

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/13262043