Change-Id: I540bdabe8ffda4697315fa6f09ad710c05b4a94d
Reviewed-on: https://go-review.googlesource.com/78134
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

ctx.Done() == ctx.Background().Done() is just
a long way to write ctx.Done() == nil.
Use the short way.

Change-Id: I7b3198b5dc46b8b40086243aa61882bc8c268eac
Reviewed-on: https://go-review.googlesource.com/78128
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Originally we tried the strict -er suffix as the rule in this case
but eventually we decided it was too awkward: io.WriteByter
became io.ByteWriter. By analogy, here the interface should be
named SessionResetter instead of the awkward ResetSessioner.

This change should not affect any drivers that have already
implemented the interface, because the method name is not changing.

(This was added during the Go 1.10 cycle and has not been
released yet, so we can change it.)

Change-Id: Ie50e4e090d3811f85965da9da37d966e9f45e79d
Reviewed-on: https://go-review.googlesource.com/78127
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>

Rewrite the text added in CL 50911, which I did not understand.

Change-Id: Id6271ffe2f7c8833dd7733fe0254fa4927fac150
Reviewed-on: https://go-review.googlesource.com/78124
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

MultiWriter(w1, w2) only writes to w2 if w1.Write succeeds.
I did not know this, and it was not documented.
Document and test.

Change-Id: Idec2e8444d5a7aca0b95d07814a28daa454eb1d3
Reviewed-on: https://go-review.googlesource.com/78123
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

CL 58210 introduced this constant for reasons I don't understand.
It should not be in the exported const block, which will pollute
godoc output with a "... unexported" notice.

Also since we already have a constant named xmlnsPrefix for "xmlns",
it is very confusing to also have xmlNamespacePrefix for "xml".
If we must have the constant at all, rename it to xmlPrefix.

Change-Id: I15f937454d730005816fcd32b1acca703acf1e51
Reviewed-on: https://go-review.googlesource.com/78121
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

A record can span multiple lines (the whole reason for the extra field),
so the important fact is that it's the _start_ of the record.
Make that clear in the name.

(This API was added during the Go 1.10 cycle so it can still be cleaned up.)

Change-Id: Id95b3ceb7cdfc4aa0ed5a053cb84da8945fa5496
Reviewed-on: https://go-review.googlesource.com/78119
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

Mainly get rid of the weird zero-value struct literal,
but while we're here also group and order things a bit better:
first the reader, then the data, then the call (which takes reader then data).

Change-Id: I901b0661d85d8eaa0807e4482aac66500ca996c7
Reviewed-on: https://go-review.googlesource.com/78118
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

Apparently we maintain this list by hand (for example, CL 52351).

Change-Id: I0a0b346cf2b7b547729cb1d0fa1642de447f7bba
Reviewed-on: https://go-review.googlesource.com/78117
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Mainly capitalize the first letter.
(Followup to CL 54351.)

Change-Id: I2d5c3d72c53d3468de7a9d4af8bd009182ff3d38
Reviewed-on: https://go-review.googlesource.com/78114
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

CL 65851 (bytes) and CL 65910 (strings) “improve[d] readability”
by removing the special case that bypassed the whole function body
when chars == "". In doing so, yes, the function was unindented a
level, which is nice, but the runtime of that case went from O(1) to O(n)
where n = len(s).

I don't know if anyone's code depends on the O(1) behavior in this case,
but quite possibly someone's does.

This CL adds the special case back, with a comment to prevent future
deletions, and without reindenting each function body in full.

Change-Id: I5aba33922b304dd1b8657e6d51d6c937a7f95c81
Reviewed-on: https://go-review.googlesource.com/78112
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

ExampleTrimLeft was inexplicably complex.

Change-Id: I13ca81bdeba728bdd632acf82e3a1101d29b9f39
Reviewed-on: https://go-review.googlesource.com/78111
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

This should help make clear that Len is not counting runes.
Also delete empty string, which doesn't add much.

Change-Id: I1602352df1897fef6e855e9db0bababb8ab788ca
Reviewed-on: https://go-review.googlesource.com/78110
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

Change-Id: If7ec07be4ecb0c1d6a1eb5c0740f150473aea6fa
Reviewed-on: https://go-review.googlesource.com/78130
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Change error message prefix from "tar:" to "archive/tar:" to maintain
backwards compatibility with Go1.9 and earlier in the unfortunate event
that someone is relying on string parsing of errors.

Fixes #22740

Change-Id: I59039c59818a0599e9d3b06bb5a531aa22a389b8
Reviewed-on: https://go-review.googlesource.com/77933Reviewed-by: roger peppe <rogpeppe@gmail.com>

If a composite literal contains any comments on their own lines without
any elements, the printer would unindent the comments.

The comments in this edge case are written when the closing '}' is
written. Indent and outdent first so that the indentation is
interspersed before the comment is written.

Also note that the go/printer golden tests don't show the exact same
behaviour that gofmt does. Added a TODO to figure this out in a separate
CL.

While at it, ensure that the tree conforms to gofmt. The changes are
unrelated to this indentation fix, however.

Fixes #22355.

Change-Id: I5ac25ac6de95a236f1e123479127cc4dd71e93fe
Reviewed-on: https://go-review.googlesource.com/74232
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Robert Griesemer <gri@golang.org>

The CPU time reported in the gctrace for STW phases is simply
work.stwprocs times the wall-clock duration of these phases. However,
work.stwprocs is set to gcprocs(), which is wrong for multiple
reasons:

1. gcprocs is intended to limit the number of Ms used for mark
   termination based on how well the garbage collector actually
   scales, but the gctrace wants to report how much CPU time is being
   stolen from the application. During STW, that's *all* of the CPU,
   regardless of how many the garbage collector can actually use.

2. gcprocs assumes it's being called during STW, so it limits its
   result to sched.nmidle+1. However, we're not calling it during STW,
   so sched.nmidle is typically quite small, even if GOMAXPROCS is
   quite large.

Fix this by setting work.stwprocs to min(ncpu, GOMAXPROCS). This also
fixes the overall GC CPU fraction, which is based on the computed CPU
times.

Fixes #22725.

Change-Id: I64b5ce87e28dbec6870aa068ce7aecdd28c058d1
Reviewed-on: https://go-review.googlesource.com/77710
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>

Use IndexByte first, as it allows us to skip lots of bytes quickly.
If IndexByte is generating a lot of false positives, switch over to Rabin-Karp.

Experiments for ppc64le
bytes:
name                             old time/op  new time/op  delta
IndexPeriodic/IndexPeriodic2-2   1.12ms ± 0%  0.18ms ± 0%  -83.54%  (p=0.000 n=10+9)
IndexPeriodic/IndexPeriodic4-2    635µs ± 0%   184µs ± 0%  -71.06%  (p=0.000 n=9+9)
IndexPeriodic/IndexPeriodic8-2    289µs ± 0%   184µs ± 0%  -36.51%  (p=0.000 n=10+9)
IndexPeriodic/IndexPeriodic16-2   133µs ± 0%   183µs ± 0%  +37.68%  (p=0.000 n=10+9)
IndexPeriodic/IndexPeriodic32-2  68.3µs ± 0%  70.2µs ± 0%   +2.76%  (p=0.000 n=10+10)
IndexPeriodic/IndexPeriodic64-2  35.8µs ± 0%  36.6µs ± 0%   +2.17%  (p=0.000 n=8+10)

strings:
name                             old time/op  new time/op  delta
IndexPeriodic/IndexPeriodic2-2    184µs ± 0%   184µs ± 0%   +0.11%  (p=0.029 n=4+4)
IndexPeriodic/IndexPeriodic4-2    184µs ± 0%   184µs ± 0%     ~     (p=0.886 n=4+4)
IndexPeriodic/IndexPeriodic8-2    184µs ± 0%   184µs ± 0%     ~     (p=0.486 n=4+4)
IndexPeriodic/IndexPeriodic16-2   185µs ± 1%   184µs ± 0%     ~     (p=0.343 n=4+4)
IndexPeriodic/IndexPeriodic32-2   184µs ± 0%    69µs ± 0%  -62.37%  (p=0.029 n=4+4)
IndexPeriodic/IndexPeriodic64-2   184µs ± 0%    37µs ± 0%  -80.17%  (p=0.029 n=4+4)

Fixes #22578

Change-Id: If2a4d8554cb96bfd699b58149d13ac294615f8b8
Reviewed-on: https://go-review.googlesource.com/76070Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>

Additions to:
https://go-review.googlesource.com/c/go/+/61570
https://go-review.googlesource.com/c/go/+/61550

Change-Id: Id89e1119333a8721cb9720a04a01dab1f2705fa9
Reviewed-on: https://go-review.googlesource.com/77591
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I63f3d2edb09801c99957a1f744639523fb6d0b62
Reviewed-on: https://go-review.googlesource.com/60331Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I259a6ed6a1abc63d2dc39eca7e85f94cf38001cc
Reviewed-on: https://go-review.googlesource.com/47342Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I9bb7568ca16b420254796eb38dfb86c5ca3399d7
Reviewed-on: https://go-review.googlesource.com/77890Reviewed-by: Ian Lance Taylor <iant@golang.org>

Permit the C preamble to use the _GoString_ type. Permit Go code to
pass string values directly to those C types. Add accessors for C
code to retrieve sizes and pointers.

Fixes #6907

Change-Id: I190c88319ec88a3ef0ddb99f342a843ba69fcaa3
Reviewed-on: https://go-review.googlesource.com/70890
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Change-Id: Ib9ec3524b712e016a9dd2fbee5555362c1a0cb59
Reviewed-on: https://go-review.googlesource.com/77770Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Update runtime asm_arm64.s and memclr_arm64.s to improve performance by using
SIMD instructions to do more in parallel. It shows improvement on bytes, html
and go1 benchmarks (particualrly regexp, which uses IndexByte frequently).

Benchmark results of bytes:

name                     old time/op   new time/op    delta
IndexByte/10-8            28.5ns ± 0%    19.5ns ± 0%   -31.58%  (p=0.000 n=10+10)
IndexByte/32-8            52.6ns ± 0%    19.0ns ± 0%   -63.88%  (p=0.000 n=10+10)
IndexByte/4K-8            4.12µs ± 0%    0.49µs ± 0%   -88.16%  (p=0.000 n=10+10)
IndexByte/4M-8            4.29ms ± 1%    0.70ms ±26%   -83.65%  (p=0.000 n=10+10)
IndexByte/64M-8           69.7ms ± 0%    16.0ms ± 0%   -76.97%  (p=0.000 n=9+10)
IndexBytePortable/10-8    34.0ns ± 0%    34.0ns ± 0%      ~     (all equal)
IndexBytePortable/32-8    66.1ns ± 0%    66.1ns ± 0%      ~     (p=0.471 n=9+9)
IndexBytePortable/4K-8    6.17µs ± 0%    6.17µs ± 0%      ~     (all equal)
IndexBytePortable/4M-8    6.33ms ± 0%    6.35ms ± 0%    +0.21%  (p=0.002 n=10+9)
IndexBytePortable/64M-8    103ms ± 0%     103ms ± 0%    +0.01%  (p=0.017 n=9+10)

name                     old speed     new speed      delta
IndexByte/10-8           351MB/s ± 0%   512MB/s ± 0%   +46.14%  (p=0.000 n=9+10)
IndexByte/32-8           609MB/s ± 0%  1683MB/s ± 0%  +176.40%  (p=0.000 n=10+10)
IndexByte/4K-8           994MB/s ± 0%  8378MB/s ± 0%  +742.75%  (p=0.000 n=10+10)
IndexByte/4M-8           977MB/s ± 1%  6149MB/s ±32%  +529.29%  (p=0.000 n=10+10)
IndexByte/64M-8          963MB/s ± 0%  4182MB/s ± 0%  +334.29%  (p=0.000 n=9+10)
IndexBytePortable/10-8   294MB/s ± 0%   294MB/s ± 0%    +0.17%  (p=0.000 n=8+8)
IndexBytePortable/32-8   484MB/s ± 0%   484MB/s ± 0%      ~     (p=0.877 n=9+9)
IndexBytePortable/4K-8   664MB/s ± 0%   664MB/s ± 0%      ~     (p=0.242 n=8+9)
IndexBytePortable/4M-8   662MB/s ± 0%   661MB/s ± 0%    -0.21%  (p=0.002 n=10+9)
IndexBytePortable/64M-8  652MB/s ± 0%   652MB/s ± 0%      ~     (p=0.065 n=10+10)

Benchmark results of html:

name              old time/op  new time/op  delta
Escape-8          62.0µs ± 1%  61.0µs ± 1%   -1.69%  (p=0.000 n=9+10)
EscapeNone-8      10.2µs ± 0%  10.2µs ± 0%   -0.09%  (p=0.022 n=9+10)
Unescape-8        71.9µs ± 0%  68.7µs ± 0%   -4.35%  (p=0.000 n=10+10)
UnescapeNone-8    4.03µs ± 0%  0.48µs ± 0%  -88.08%  (p=0.000 n=10+10)
UnescapeSparse-8  10.7µs ± 2%   7.1µs ± 3%  -33.91%  (p=0.000 n=10+10)
UnescapeDense-8   53.2µs ± 1%  53.5µs ± 1%     ~     (p=0.143 n=10+10)

Benchmark results of go1:

name                     old time/op    new time/op    delta
BinaryTree17-8              6.53s ± 0%     6.48s ± 2%      ~     (p=0.190 n=4+5)
Fannkuch11-8                6.35s ± 1%     6.35s ± 0%      ~     (p=1.000 n=5+5)
FmtFprintfEmpty-8           108ns ± 1%     101ns ± 2%    -6.32%  (p=0.008 n=5+5)
FmtFprintfString-8          172ns ± 1%     182ns ± 2%    +5.70%  (p=0.008 n=5+5)
FmtFprintfInt-8             207ns ± 0%     207ns ± 0%      ~     (p=0.444 n=5+5)
FmtFprintfIntInt-8          277ns ± 1%     276ns ± 1%      ~     (p=0.873 n=5+5)
FmtFprintfPrefixedInt-8     386ns ± 0%     382ns ± 1%    -1.04%  (p=0.024 n=5+5)
FmtFprintfFloat-8           492ns ± 0%     492ns ± 1%      ~     (p=0.571 n=4+5)
FmtManyArgs-8              1.32µs ± 1%    1.33µs ± 0%      ~     (p=0.087 n=5+5)
GobDecode-8                16.8ms ± 2%    16.7ms ± 1%      ~     (p=1.000 n=5+5)
GobEncode-8                14.1ms ± 1%    14.0ms ± 1%      ~     (p=0.056 n=5+5)
Gzip-8                      788ms ± 0%     802ms ± 0%    +1.71%  (p=0.008 n=5+5)
Gunzip-8                   83.6ms ± 0%    83.9ms ± 0%    +0.40%  (p=0.008 n=5+5)
HTTPClientServer-8          120µs ± 0%     120µs ± 1%      ~     (p=0.548 n=5+5)
JSONEncode-8               33.2ms ± 0%    33.0ms ± 1%    -0.71%  (p=0.008 n=5+5)
JSONDecode-8                152ms ± 1%     152ms ± 1%      ~     (p=1.000 n=5+5)
Mandelbrot200-8            10.0ms ± 0%    10.0ms ± 0%    -0.05%  (p=0.008 n=5+5)
GoParse-8                  7.97ms ± 0%    7.98ms ± 0%      ~     (p=0.690 n=5+5)
RegexpMatchEasy0_32-8       233ns ± 1%     206ns ± 0%   -11.44%  (p=0.016 n=5+4)
RegexpMatchEasy0_1K-8      1.86µs ± 0%    0.77µs ± 1%   -58.54%  (p=0.008 n=5+5)
RegexpMatchEasy1_32-8       250ns ± 0%     205ns ± 0%   -18.07%  (p=0.008 n=5+5)
RegexpMatchEasy1_1K-8      2.28µs ± 0%    1.11µs ± 0%   -51.09%  (p=0.029 n=4+4)
RegexpMatchMedium_32-8      332ns ± 1%     301ns ± 2%    -9.45%  (p=0.008 n=5+5)
RegexpMatchMedium_1K-8     85.5µs ± 2%    78.8µs ± 0%    -7.83%  (p=0.008 n=5+5)
RegexpMatchHard_32-8       4.34µs ± 1%    4.27µs ± 0%    -1.49%  (p=0.008 n=5+5)
RegexpMatchHard_1K-8        130µs ± 1%     127µs ± 0%    -2.53%  (p=0.008 n=5+5)
Revcomp-8                   1.35s ± 1%     1.13s ± 1%   -16.17%  (p=0.008 n=5+5)
Template-8                  160ms ± 2%     162ms ± 2%      ~     (p=0.222 n=5+5)
TimeParse-8                 795ns ± 2%     778ns ± 1%      ~     (p=0.095 n=5+5)
TimeFormat-8                782ns ± 0%     786ns ± 1%    +0.59%  (p=0.040 n=5+5)

name                     old speed      new speed      delta
GobDecode-8              45.8MB/s ± 2%  45.9MB/s ± 1%      ~     (p=1.000 n=5+5)
GobEncode-8              54.3MB/s ± 1%  55.0MB/s ± 1%      ~     (p=0.056 n=5+5)
Gzip-8                   24.6MB/s ± 0%  24.2MB/s ± 0%    -1.69%  (p=0.008 n=5+5)
Gunzip-8                  232MB/s ± 0%   231MB/s ± 0%    -0.40%  (p=0.008 n=5+5)
JSONEncode-8             58.4MB/s ± 0%  58.8MB/s ± 1%    +0.71%  (p=0.008 n=5+5)
JSONDecode-8             12.8MB/s ± 1%  12.8MB/s ± 1%      ~     (p=1.000 n=5+5)
GoParse-8                7.27MB/s ± 0%  7.26MB/s ± 0%      ~     (p=0.762 n=5+5)
RegexpMatchEasy0_32-8     137MB/s ± 1%   155MB/s ± 0%   +12.93%  (p=0.008 n=5+5)
RegexpMatchEasy0_1K-8     551MB/s ± 0%  1329MB/s ± 1%  +141.11%  (p=0.008 n=5+5)
RegexpMatchEasy1_32-8     128MB/s ± 0%   156MB/s ± 0%   +22.00%  (p=0.008 n=5+5)
RegexpMatchEasy1_1K-8     449MB/s ± 0%   920MB/s ± 0%  +104.68%  (p=0.016 n=4+5)
RegexpMatchMedium_32-8   3.00MB/s ± 0%  3.32MB/s ± 2%   +10.60%  (p=0.016 n=4+5)
RegexpMatchMedium_1K-8   12.0MB/s ± 2%  13.0MB/s ± 0%    +8.48%  (p=0.008 n=5+5)
RegexpMatchHard_32-8     7.38MB/s ± 1%  7.49MB/s ± 0%    +1.49%  (p=0.008 n=5+5)
RegexpMatchHard_1K-8     7.88MB/s ± 1%  8.08MB/s ± 0%    +2.59%  (p=0.008 n=5+5)
Revcomp-8                 188MB/s ± 1%   224MB/s ± 1%   +19.29%  (p=0.008 n=5+5)
Template-8               12.2MB/s ± 2%  12.0MB/s ± 2%      ~     (p=0.206 n=5+5)

Change-Id: I94116620a287d173a6f60510684362e500f54887
Reviewed-on: https://go-review.googlesource.com/33597
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Fixes #20924

Change-Id: If89f31da63cbea38d7e615a428b7b07629770a45
Reviewed-on: https://go-review.googlesource.com/47851
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tim Cooper <tim.cooper@layeh.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Included in a warning that EncodeToMemory may return an incomplete PEM
encoded structure if invalid headers are supplied. Example:

	pem.EncodeToMemory(&pem.Block{
		Headers: map[string]string{
			"a":   "test1",
			"b:c": "test2",
		},
	})

Returns:

	-----BEGIN -----
	a: test1

Change-Id: Ia9cf0202f985e3cf210aabb6f07667e581ff081f
Reviewed-on: https://go-review.googlesource.com/77790Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

We set Content-Type to "text/plain; charset=utf-8" even with blank body
before. Let's strip this unnecessary header though it's harmless in most
cases.

Fixes #20784
Signed-off-by: Tw <tw19881113@gmail.com>

Change-Id: Ic58a410dcbc89f457c6ddd92961d9cbf545b2f4f
Reviewed-on: https://go-review.googlesource.com/46631
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Unless you go back and read the hash package documentation, it's
not clear that all the hash packages implement marshaling and
unmarshaling. Document the behaviour specifically in each package
that implements it as it this is hidden behaviour and easy to miss.

Change-Id: Id9d3508909362f1a3e53872d0319298359e50a94
Reviewed-on: https://go-review.googlesource.com/77251Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

If the Linux kernel was built with CONFIG_OPTIMIZE_INLINING=n and was
built with hardening options turned on, GCC will insert a stack probe
in the VDSO function that requires a full page of stack space.
The stack probe can corrupt memory if another thread is using it.
Avoid sporadic crashes by calling the VDSO on the g0 or gsignal stack.

While we're at it, align the stack as C code expects. We've been
getting away with a misaligned stack, but it's possible that the VDSO
code will change in the future to break that assumption.

Benchmarks show a 11% hit on time.Now, but it's only 6ns.

name                      old time/op  new time/op  delta
AfterFunc-12              1.66ms ± 0%  1.66ms ± 1%     ~     (p=0.905 n=9+10)
After-12                  1.90ms ± 6%  1.86ms ± 0%   -2.05%  (p=0.012 n=10+8)
Stop-12                    113µs ± 3%   115µs ± 2%   +1.60%  (p=0.017 n=9+10)
SimultaneousAfterFunc-12   145µs ± 1%   144µs ± 0%   -0.68%  (p=0.002 n=10+8)
StartStop-12              39.5µs ± 3%  40.4µs ± 5%   +2.19%  (p=0.023 n=10+10)
Reset-12                  10.2µs ± 0%  10.4µs ± 0%   +2.45%  (p=0.000 n=10+9)
Sleep-12                   190µs ± 1%   190µs ± 1%     ~     (p=0.971 n=10+10)
Ticker-12                 4.68ms ± 2%  4.64ms ± 2%   -0.83%  (p=0.043 n=9+10)
Now-12                    48.4ns ±11%  54.0ns ±11%  +11.42%  (p=0.017 n=10+10)
NowUnixNano-12            48.5ns ±13%  56.9ns ± 8%  +17.30%  (p=0.000 n=10+10)
Format-12                  489ns ±11%   504ns ± 6%     ~     (p=0.289 n=10+10)
FormatNow-12               436ns ±23%   480ns ±13%  +10.25%  (p=0.026 n=9+10)
MarshalJSON-12             656ns ±14%   587ns ±24%     ~     (p=0.063 n=10+10)
MarshalText-12             647ns ± 7%   638ns ± 9%     ~     (p=0.516 n=10+10)
Parse-12                   348ns ± 8%   328ns ± 9%   -5.66%  (p=0.030 n=10+10)
ParseDuration-12           136ns ± 9%   140ns ±11%     ~     (p=0.425 n=10+10)
Hour-12                   14.8ns ± 6%  15.6ns ±11%     ~     (p=0.085 n=10+10)
Second-12                 14.0ns ± 6%  14.3ns ±12%     ~     (p=0.443 n=10+10)
Year-12                   32.4ns ±11%  33.4ns ± 6%     ~     (p=0.492 n=10+10)
Day-12                    41.5ns ± 9%  42.3ns ±12%     ~     (p=0.239 n=10+10)

Fixes #20427

Change-Id: Ia395cbb863215f4499b8e7ef95f4b99f51090911
Reviewed-on: https://go-review.googlesource.com/76990Reviewed-by: Austin Clements <austin@google.com>

I verified this change on a corpus of > 200 GB of emails since the mid-90s. With
this change, more addresses parse than before, and anything which parsed before
still parses.

In said corpus, I came across the edge case of comments preceding an
addr-spec (with angle brackets!), e.g. “(John Doe) <john@example.com>”, which
does not satisfy the conditions to be treated as a fallback, as per my reading
of RFC2822.

This change does not parse quoted-strings within comments (a corresponding TODO
is in the code), but I have not seen that in the wild.

Fixes #22670

Change-Id: I526fcf7c6390aa1c219fdec1852f26c514506f76
Reviewed-on: https://go-review.googlesource.com/77474Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

GDB 7.5 recognizes DWARF4 by default.

GDB 7.5 release note does not explicitly mention DWARF4 support
but according to GCC 4.8 release note
 https://gcc.gnu.org/gcc-4.8/changes.html

 "DWARF4 is now the default when generating DWARF debug
 information. ...
 GDB 7.5, Valgrind 3.8.0 and elfutils 0.154 debug information
 consumers support DWARF4 by default."

Change-Id: I56b011c7c38fbc103bbd366ceaea3b709c66ab7f
Reviewed-on: https://go-review.googlesource.com/77570Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>

change hash/crc32 package to use cpu package instead of using
runtime internal variables to check crc32 instruction

Change-Id: I8f88d2351bde8ed4e256f9adf822a08b9a00f532
Reviewed-on: https://go-review.googlesource.com/76490Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

I submitted two CLs which broke the build. Add temporary placeholder
with false bools to fix the build and restore old behavior.

Updates golang/go#22718 (details of why it broke)

Change-Id: I1f30624e14f631a95f4eff5aae462f1091f723a2
Reviewed-on: https://go-review.googlesource.com/77590Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Optimize with ARMv8 SHA256 instructions.
Result (Cortex-A72)

name           old time/op    new time/op      delta
Hash8Bytes-64    1.54µs ± 1%      0.61µs ± 9%    -60.67%  (p=0.008 n=5+5)
Hash1K-64        17.2µs ± 1%       1.4µs ± 2%    -91.91%  (p=0.008 n=5+5)
Hash8K-64         127µs ± 0%         7µs ± 1%    -94.42%  (p=0.008 n=5+5)

name           old speed      new speed        delta
Hash8Bytes-64  5.20MB/s ± 1%   13.23MB/s ±10%   +154.58%  (p=0.008 n=5+5)
Hash1K-64      59.4MB/s ± 1%   735.1MB/s ± 2%  +1136.96%  (p=0.008 n=5+5)
Hash8K-64      64.5MB/s ± 0%  1156.3MB/s ± 1%  +1692.75%  (p=0.008 n=5+5)

Change-Id: I47eca6471b75cd07cb0c77477053a07d0de7494f
Reviewed-on: https://go-review.googlesource.com/61570Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Optimize with ARMv8 SHA1 instructions.
Results (Cortex-A72)

name             old time/op    new time/op     delta
Hash8Bytes-64      1.06µs ± 4%     0.56µs ± 4%   -47.19%  (p=0.008 n=5+5)
Hash320Bytes-64    3.92µs ± 1%     0.82µs ± 2%   -79.07%  (p=0.008 n=5+5)
Hash1K-64          10.2µs ± 2%      1.5µs ± 2%   -85.71%  (p=0.008 n=5+5)
Hash8K-64          73.9µs ± 1%      7.6µs ± 1%   -89.66%  (p=0.008 n=5+5)

name             old speed      new speed       delta
Hash8Bytes-64    7.55MB/s ± 4%  14.29MB/s ± 4%   +89.27%  (p=0.008 n=5+5)
Hash320Bytes-64  81.6MB/s ± 1%  390.0MB/s ± 2%  +377.64%  (p=0.008 n=5+5)
Hash1K-64         100MB/s ± 2%    701MB/s ± 2%  +599.65%  (p=0.008 n=5+5)
Hash8K-64         111MB/s ± 1%   1072MB/s ± 1%  +867.44%  (p=0.008 n=5+5)

Change-Id: I84397f980db9518f4150ac4c5ffa2c5a97a34444
Reviewed-on: https://go-review.googlesource.com/61550Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

A clarifying comment was added to indicate that overflow of a
single Word is not possible in the single digit calculation.
Lehmer's paper includes a proof of the bounds on the size of the
cosequences (u0, u1, u2, v0, v1, v2).

Change-Id: I98127a07aa8f8fe44814b74b2bc6ff720805194b
Reviewed-on: https://go-review.googlesource.com/77451Reviewed-by: Robert Griesemer <gri@golang.org>

Previously when RoundTrip returned a non-nil error, the proxy returned a
StatusBadGateway error, instead of first calling ModifyResponse. This
commit first calls ModifyResponse, whether or not the error returned
from RoundTrip is nil.

Also closes response body when ModifyResponse returns an error. See #22658.

Fixes #21255

Change-Id: I5b5bf23a69ae5608f87d4ece756a1b4985ccaa9c
Reviewed-on: https://go-review.googlesource.com/54030Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

In the doc for QueryUnescape and PathUnescape, clarify that by 0xAB we
means a substring with any two valid hexadecimal digits.

Fixes #18642

Change-Id: Ib65b130995ae5fcf07e25ee0fcc41fad520c5662
Reviewed-on: https://go-review.googlesource.com/77050Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #22703

The fix was already done by Cherry for defer/go of an interface call (CL 23820).
We just need to do it everywhere.

Change-Id: I0115d22e443931fe1bcce44c93c4d0770b5fd268
Reviewed-on: https://go-review.googlesource.com/77450
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>