Fixes #16243.

Change-Id: I207d1e8aa48abe453a23c709ccf4f8e07368595b
Reviewed-on: https://go-review.googlesource.com/24648
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The frontend may emit node with line number missing. In this case,
use the parent line number. Instead of changing every call site of
pushLine, do it in pushLine itself.

Fixes #16214.

Change-Id: I80390550b56e4d690fc770b01ff725b892ffd6dc
Reviewed-on: https://go-review.googlesource.com/24641Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates x/net/http2 to git rev b400c2e for https://golang.org/cl/24214,
"http2: add additional blacklisted ciphersuites"

Both TLS_RSA_WITH_AES_128_GCM_SHA256 & TLS_RSA_WITH_AES_256_GCM_SHA384
are now blacklisted, per http://httpwg.org/specs/rfc7540.html#BadCipherSuites

Change-Id: I8b9a7f4dc3c152d0675e196523ddd36111744984
Reviewed-on: https://go-review.googlesource.com/24684Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

+ test.

Fixes #16230

Change-Id: Idac995437146a9df9e73f094d2a31abc25b1fa62
Reviewed-on: https://go-review.googlesource.com/24681Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

We had ~30 one way, and these four new occurrences the other way.

Updates #11626

Change-Id: Ic6403dc4905874916ae292ff739d33482ed8e5bf
Reviewed-on: https://go-review.googlesource.com/24683Reviewed-by: Rob Pike <r@golang.org>

Fixes #16230

Change-Id: Ibb10234a6c3ab8bd0cfd93c2ebe8cfa66f80f6b0
Reviewed-on: https://go-review.googlesource.com/24682Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Ctz is a hot-spot in the Go 1.7 memory manager. In SSA it's
implemented as an intrinsic that compiles to a few instructions, but
on the old backend (all architectures other than amd64), it's
implemented as a fairly complex Go function. As a result, switching to
bitmap-based allocation was a significant hit to allocation-heavy
workloads like BinaryTree17 on non-SSA platforms.

For unknown reasons, this hit 386 particularly hard. We can regain a
lot of the lost performance by implementing Ctz in assembly on the
386. This isn't as good as an intrinsic, since it still generates a
function call and prevents useful inlining, but it's much better than
the pure Go implementation:

name                      old time/op    new time/op    delta
BinaryTree17-12              3.59s ± 1%     3.06s ± 1%  -14.74%  (p=0.000 n=19+20)
Fannkuch11-12                3.72s ± 1%     3.64s ± 1%   -2.09%  (p=0.000 n=17+19)
FmtFprintfEmpty-12          52.3ns ± 3%    52.3ns ± 3%     ~     (p=0.829 n=20+19)
FmtFprintfString-12          156ns ± 1%     148ns ± 3%   -5.20%  (p=0.000 n=18+19)
FmtFprintfInt-12             137ns ± 1%     136ns ± 1%   -0.56%  (p=0.000 n=19+13)
FmtFprintfIntInt-12          227ns ± 2%     225ns ± 2%   -0.93%  (p=0.000 n=19+17)
FmtFprintfPrefixedInt-12     210ns ± 1%     208ns ± 1%   -0.91%  (p=0.000 n=19+17)
FmtFprintfFloat-12           375ns ± 1%     371ns ± 1%   -1.06%  (p=0.000 n=19+18)
FmtManyArgs-12               995ns ± 2%     978ns ± 1%   -1.63%  (p=0.000 n=17+17)
GobDecode-12                9.33ms ± 1%    9.19ms ± 0%   -1.59%  (p=0.000 n=20+17)
GobEncode-12                7.73ms ± 1%    7.73ms ± 1%     ~     (p=0.771 n=19+20)
Gzip-12                      375ms ± 1%     374ms ± 1%     ~     (p=0.141 n=20+18)
Gunzip-12                   61.8ms ± 1%    61.8ms ± 1%     ~     (p=0.602 n=20+20)
HTTPClientServer-12         87.7µs ± 2%    86.9µs ± 3%   -0.87%  (p=0.024 n=19+20)
JSONEncode-12               20.2ms ± 1%    20.4ms ± 0%   +0.53%  (p=0.000 n=18+19)
JSONDecode-12               65.3ms ± 0%    65.4ms ± 1%     ~     (p=0.385 n=16+19)
Mandelbrot200-12            4.11ms ± 1%    4.12ms ± 0%   +0.29%  (p=0.020 n=19+19)
GoParse-12                  3.75ms ± 1%    3.61ms ± 2%   -3.90%  (p=0.000 n=20+20)
RegexpMatchEasy0_32-12       104ns ± 0%     103ns ± 0%   -0.96%  (p=0.000 n=13+16)
RegexpMatchEasy0_1K-12       805ns ± 1%     803ns ± 1%     ~     (p=0.189 n=18+18)
RegexpMatchEasy1_32-12       111ns ± 0%     111ns ± 3%     ~     (p=1.000 n=14+19)
RegexpMatchEasy1_1K-12      1.00µs ± 1%    1.00µs ± 1%   +0.50%  (p=0.003 n=19+19)
RegexpMatchMedium_32-12      133ns ± 2%     133ns ± 2%     ~     (p=0.218 n=20+20)
RegexpMatchMedium_1K-12     41.2µs ± 1%    42.2µs ± 1%   +2.52%  (p=0.000 n=18+16)
RegexpMatchHard_32-12       2.35µs ± 1%    2.38µs ± 1%   +1.53%  (p=0.000 n=18+18)
RegexpMatchHard_1K-12       70.9µs ± 2%    72.0µs ± 1%   +1.42%  (p=0.000 n=19+17)
Revcomp-12                   1.06s ± 0%     1.05s ± 0%   -1.36%  (p=0.000 n=20+18)
Template-12                 86.2ms ± 1%    84.6ms ± 0%   -1.89%  (p=0.000 n=20+18)
TimeParse-12                 425ns ± 2%     428ns ± 1%   +0.77%  (p=0.000 n=18+19)
TimeFormat-12                517ns ± 1%     519ns ± 1%   +0.43%  (p=0.001 n=20+19)
[Geo mean]                  74.3µs         73.5µs        -1.05%

Prior to this commit, BinaryTree17-12 on 386 was 33% slower than at
the go1.6 tag. With this commit, it's 13% slower.

On arm and arm64, BinaryTree17-12 is only ~5% slower than it was at
go1.6. It may be worth implementing Ctz for them as well.

I consider this change low risk, since the functions it replaces are
simple, very well specified, and well tested.

For #16117.

Change-Id: Ic39d851d5aca91330134596effd2dab9689ba066
Reviewed-on: https://go-review.googlesource.com/24640Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Previously we started checking for context cancelation in Wait, but
that meant that when using StdoutPipe context cancelation never took
effect.

Fixes #16222.

Change-Id: I89cd26d3499a6080bf1a07718ce38d825561899e
Reviewed-on: https://go-review.googlesource.com/24650Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This should fix the report at #16224, and also fixes running the test as
root on my Ubuntu Trusty system.

Fixes #16224.

Change-Id: I4e3b5527aa63366afb33a7e30efab088d34fb302
Reviewed-on: https://go-review.googlesource.com/24670
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates x/net/http2 to git rev 8e573f40 for https://golang.org/cl/24600,
"http2: merge multiple GOAWAY frames' contents into error message"

Fixes #14627 (more)

Change-Id: I5231607c2c9e0d854ad6199ded43c59e59f62f52
Reviewed-on: https://go-review.googlesource.com/24612
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

There was only one use of "HTTP/1.n" compared to "HTTP/1.x":

h2_bundle.go://   "Just as in HTTP/1.x, header field names are strings of ASCII
httputil/dump.go:// DumpRequest returns the given request in its HTTP/1.x wire
httputil/dump.go:// intact. HTTP/2 requests are dumped in HTTP/1.x form, not in their
response.go:// Write writes r to w in the HTTP/1.x server response format,
server.go:      // Request.Body. For HTTP/1.x requests, handlers should read any
server.go:// The default HTTP/1.x and HTTP/2 ResponseWriter implementations
server.go:// The default ResponseWriter for HTTP/1.x connections supports
server.go:// http1ServerSupportsRequest reports whether Go's HTTP/1.x server
server.go:      // about HTTP/1.x Handlers concurrently reading and writing, like
server.go:      // HTTP/1.x from here on.
transport.go:   return fmt.Errorf("net/http: HTTP/1.x transport connection broken: %v", err)

Be consistent.

Change-Id: I93c4c873e500f51af2b4762055e22f5487a625ac
Reviewed-on: https://go-review.googlesource.com/24610Reviewed-by: Andrew Gerrand <adg@golang.org>

Change-Id: I2b7a81cb809d109f10d5f0db957c614f466d6bfd
Reviewed-on: https://go-review.googlesource.com/24582Reviewed-by: Adam Langley <agl@golang.org>

I believe it's necessary to use a buffer size smaller than 64KB because
(at least some versions of) Window using a TCP receive window less than
64KB. Currently the client and server use buffer sizes of 16KB and 32KB,
respectively (the server uses io.Copy, which defaults to 32KB internally).
Since the server has been using 32KB, it should be safe for the client to
do so as well.

Fixes #15899

Change-Id: I36d44b29f2a5022c03fc086213d3c1adf153e983
Reviewed-on: https://go-review.googlesource.com/24581Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The assembly is broken: it does `MOVQ g(R12), R14` expecting that
R12 contains tls address, but it does not do get_tls(R12) before.
This magically works on linux: `MOVQ g(R12), R14` is compiled to
`mov %fs:0xfffffffffffffff8,%r14` which does not use R12.
But it crashes on windows.

Add explicit `get_tls(R12)`.

Fixes #16206

Change-Id: Ic1f21a6fef2473bcf9147de6646929781c9c1e98
Reviewed-on: https://go-review.googlesource.com/24590Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

When the blocked field was first introduced back in
https://golang.org/cl/61250043 the scheduler trace code incorrectly used
m->blocked instead of mp->blocked.  That has carried through the
conversion to Go.  This CL fixes it.

Change-Id: Id81907b625221895aa5c85b9853f7c185efd8f4b
Reviewed-on: https://go-review.googlesource.com/24571Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

If creating a new thread fails with EAGAIN, point the user at ulimit.

Fixes #15476.

Change-Id: Ib36519614b5c72776ea7f218a0c62df1dd91a8ea
Reviewed-on: https://go-review.googlesource.com/24570
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates x/net/http2 to git rev ef2e00e88 for https://golang.org/cl/24560,
"http2: make Transport return server's GOAWAY error back to the user"

Fixes #14627

Change-Id: I2bb123a3041e168db7c9446beef4ee47638f17ee
Reviewed-on: https://go-review.googlesource.com/24561Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Prior to this change package "foo" had to be installed in order to check
example names in "foo_test" package.

However by the time "foo_test" package is checked a parsed "foo" package
has been already constructed. Use it to check example names.

Also change TestDivergentPackagesExamples test to pass directory of the
package to the vet tool as it is the most common way to invoke it. This
requires changes to errchk to add support for grabbing source files from
a directory.

Fixes #16189

Change-Id: Ief103d07b024822282b86c24250835cc591793e8
Reviewed-on: https://go-review.googlesource.com/24488Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

TestPendingConnsAfterErr only cared that things didn't deadlock, so 5
seconds is a sufficient timer. We don't need 100 milliseconds.

I was able to reproduce with a tiny (5 nanosecond) timeout value,
instead of 100 milliseconds. In the process of testing with -race and
a high -count= value, I noticed several data races and panics
(sendings on a closed channel) which are also fixed in this change.

Fixes #15684

Change-Id: Ib4605fcc0f296e658cb948352ed642b801cb578c
Reviewed-on: https://go-review.googlesource.com/24550Reviewed-by: Marko Tiikkaja <marko@joh.to>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

Fixes #16165

Change-Id: Ic90e5873e0c8ee044f09543177192dcae1dcdbed
Reviewed-on: https://go-review.googlesource.com/24531
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I47bd98509663d75b0d4dedbdb778e803d90053cf
Reviewed-on: https://go-review.googlesource.com/24216Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Don't configure HTTP/2 in http.Server.Serve(net.Listener) if the
Server's TLSConfig is set and doesn't include the "h2" NextProto
value. This avoids mutating a *tls.Config already in use if
previously passed to tls.NewListener.

Also document this. (it's come up a few times now)

Fixes #15908

Change-Id: I283eed82fdb29a791f80d801aadd9f75db244de0
Reviewed-on: https://go-review.googlesource.com/24508Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #16201

Change-Id: I38c17859db78c2868905da24217e0ad47739c320
Reviewed-on: https://go-review.googlesource.com/24541
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates #16124

Change-Id: Ib58f2bb37fd1559efc512a2e3cba976f09b939a0
Reviewed-on: https://go-review.googlesource.com/24520Reviewed-by: Andrew Gerrand <adg@golang.org>

Changes beyond generated tables:
- Now supports aliases to handle deprecated
  property classes.
- Some Mongolian letters are now modifiers.

Other changes:
- strconv: newly generated table to be in sync
- regexp/syntax: updated maxFold

Fixes #16191

Change-Id: I56bdf21ee2f775f2a82d0465b3772faf5c24cb61
Reviewed-on: https://go-review.googlesource.com/24496
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Several minor changes that remove a good chunk of the overhead added
to the reflect Name method over the 1.7 cycle, as seen from the
non-SSA architectures.

In particular, there are ~20 fewer instructions in reflect.name.name
on 386, and the method now qualifies for inlining.

The simple JSON decoding benchmark on darwin/386:

	name           old time/op    new time/op    delta
	CodeDecoder-8    49.2ms ± 0%    48.9ms ± 1%  -0.77%  (p=0.000 n=10+9)

	name           old speed      new speed      delta
	CodeDecoder-8  39.4MB/s ± 0%  39.7MB/s ± 1%  +0.77%  (p=0.000 n=10+9)

On darwin/amd64 the effect is less pronounced:

	name           old time/op    new time/op    delta
	CodeDecoder-8    38.9ms ± 0%    38.7ms ± 1%  -0.38%  (p=0.005 n=10+10)

	name           old speed      new speed      delta
	CodeDecoder-8  49.9MB/s ± 0%  50.1MB/s ± 1%  +0.38%  (p=0.006 n=10+10)

Counterintuitively, I get much more useful benchmark data out of my
MacBook Pro than a linux workstation with more expensive Intel chips.
While the laptop has fewer cores and an active GUI, the single-threaded
performance is significantly better (nearly 1.5x decoding throughput)
so the differences are more pronounced.

For #16117.

Change-Id: I4e0cc1cc2d271d47d5127b1ee1ca926faf34cabf
Reviewed-on: https://go-review.googlesource.com/24510Reviewed-by: Ian Lance Taylor <iant@golang.org>

This modifies a recent performance improvement to the
And8 and Or8 atomic functions which required both ppc64le
and ppc64 to use power8 instructions. Since then it was
decided that ppc64 (BE) should work for power5 and later.
This change uses instructions compatible with power5 for
ppc64 and uses power8 for ppc64le.

Fixes #16004

Change-Id: I623c75e8e6fd1fa063a53d250d86cdc9d0890dc7
Reviewed-on: https://go-review.googlesource.com/24181Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The version of pprof in gperftools has been deprecated.
No need to have a pointer to that version since go tool pprof
is included with the Go distro.

Change-Id: I6d769a68f64280f5db89ff6fbc67bfea9c8f1526
Reviewed-on: https://go-review.googlesource.com/24509Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

On linux/386 compared to tip:

	name                     old time/op  new time/op  delta
	DecodeInterfaceSlice-40  1.23ms ± 1%  1.17ms ± 1%  -4.93%  (p=0.000 n=9+10)

Recovers about half the performance regression from Go 1.6 on 386.

For #16117.

Change-Id: Ie8676d92a4da3e27ff21b91a98b3e13d16730ba1
Reviewed-on: https://go-review.googlesource.com/24468Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Do not throw away the rest of Int63 value used for
generation random bytes. Save it in Rand struct and
re-use during the next Read call.

Fixes #16124

Change-Id: Ic70bd80c3c3a6590e60ac615e8b3c2324589bea3
Reviewed-on: https://go-review.googlesource.com/24251Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #16162.

Change-Id: I6f4ae906630079ef5fc29ee5f70e2e3d1c962170
Reviewed-on: https://go-review.googlesource.com/24390Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This fixes some 40 warnings from go vet.

Fixes #16134.

Change-Id: Ib9fcba275fe692f027a2a07b581c8cf503b11087
Reviewed-on: https://go-review.googlesource.com/24287Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Change ExampleResponseRecorder to use httptest.NewRequest instead of
http.NewRequest. This makes the example shorter and shows how to use
one more function from the httptest package.

Change-Id: I3d35869bd0a4daf1c7551b649428bb2f2a45eba2
Reviewed-on: https://go-review.googlesource.com/24480
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #16197

Change-Id: Icaabacbb22bc18c52b9e04b47385ac5325fcccd1
Reviewed-on: https://go-review.googlesource.com/24505
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The compiler was treating all global function literals as occurring in a
function named "glob", which caused a symbol name collision when there
was an actual function named "glob".  Fixed by adding a period.

Fixes #16193.

Change-Id: I67792901a8ca04635ba41d172bfaee99944f594d
Reviewed-on: https://go-review.googlesource.com/24500Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

In the comments for this file there is a reference to gperftools
for more info on pprof. pprof now live on its own repo on github,
and the version in gperftools is deprecated.

Change-Id: I8a188f129534f73edd132ef4e5a2d566e69df7e9
Reviewed-on: https://go-review.googlesource.com/24502Reviewed-by: Ian Lance Taylor <iant@golang.org>

Make sure the pointer to the heap copy of an output parameter is kept
live throughout the function.  The function could panic at any point,
and then a defer could recover.  Thus, we need the pointer to the heap
copy always available so the post-deferreturn code can copy the return
value back to the stack.

Before this CL, the pointer to the heap copy could be considered dead in
certain situations, like code which is reverse dominated by a panic call.

Fixes #16095.

Change-Id: Ic3800423e563670e5b567b473bf4c84cddb49a4c
Reviewed-on: https://go-review.googlesource.com/24213
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

This fixes the obvious bug and makes go vet look for identifiers in foo
package when checking example names in foo_test package.

Note that for this check to work the foo package have to be
installed (using go install).

This commit however doesn't fix TestDivergentPackagesExamples test that
is not implemented correctly and passes only by chance.

Updates #16189

Change-Id: I5c2f675cd07e5b66cf0432b2b3e422ab45c3dedd
Reviewed-on: https://go-review.googlesource.com/24487Reviewed-by: Dmitri Shuralyov <shurcool@gmail.com>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Swtich from a sync.RWMutex to atomic.Value for cacheTypeFields.

On GOARCH=386, this recovers most of the remaining performance
difference from the 1.6 release. Compared with tip on linux/386:

	name            old time/op    new time/op    delta
	CodeDecoder-40    92.8ms ± 1%    87.7ms ± 1%  -5.50%  (p=0.000 n=10+10)

	name            old speed      new speed      delta
	CodeDecoder-40  20.9MB/s ± 1%  22.1MB/s ± 1%  +5.83%  (p=0.000 n=10+10)

With more time and care, I believe more of the JSON decoder's work
could be shifted so it is done before decoding, and independent of
the number of bytes processed. Maybe someone could explore that for
Go 1.8.

For #16117.

Change-Id: I049655b2e5b76384a0d5f4b90e3ec7cc8d8c4340
Reviewed-on: https://go-review.googlesource.com/24472
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #15788

Change-Id: I5a1fd1e5992f1c16cf8d8437d742bf02e1653b9c
Reviewed-on: https://go-review.googlesource.com/23461Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>