And fix the wrong comment.

Initially found this because the comment was wrong about the possible
values. Then noticed that there doesn't seem to be any reason to use
uintptr over SelectDir.

Change-Id: I4f9f9640e49d89e558ed00bd99e57dab890785f5
Reviewed-on: https://go-review.googlesource.com/20655Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Only compute the number of maximum allowed elements per slice once.
Special case newcap computation for slices with byte sized elements.

name              old time/op  new time/op  delta
GrowSliceBytes-2  61.1ns ± 1%  43.4ns ± 1%  -29.00%  (p=0.000 n=20+20)
GrowSliceInts-2   85.9ns ± 1%  75.7ns ± 1%  -11.80%  (p=0.000 n=20+20)

Change-Id: I5d9c0d5987cdd108ac29dc32e31912dcefa2324d
Reviewed-on: https://go-review.googlesource.com/20653Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

It was failing like "unknown groupid ᎈ|" instead of "unknown groupid
5000" due to the conversion from int to string.

Updates #14806

Change-Id: I83e4b478ff628ad4053573a9f32b3fadce22e847
Reviewed-on: https://go-review.googlesource.com/20642Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Fixes #11419.

Change-Id: I7935a253e3e96191a33f5041bab203ecc5f0c976
Reviewed-on: https://go-review.googlesource.com/20647Reviewed-by: Keith Randall <khr@golang.org>

* Shaves about 10k from pkg/tools/linux_amd64.
* Was suggested by drchase before
* Found by looking at ssa output of #14758

Change-Id: If2c4ddf3b2603d4dfd8fb4d9199b9a3dcb05b17d
Reviewed-on: https://go-review.googlesource.com/20570Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Simplify function signature.
Remove unused Ctxt field Enforce_data_order.

Passes toolstash -cmp.

Change-Id: I5caa270ca9ae725708fe415b2c978b5f40780255
Reviewed-on: https://go-review.googlesource.com/20644
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Passes toolstash -cmp.

Change-Id: Ib8c76081956e1d4eecef16b82bc8d527d7849d7e
Reviewed-on: https://go-review.googlesource.com/20643
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

pprof crashed when running with:

     go tool pprof %INVALID

Change-Id: I47c2a4da7273e3a97a833f320a650b8c6b59d6b9
Reviewed-on: https://go-review.googlesource.com/20632Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This makes the output of compiling with -S more
stable in the face of unimportant variation in the
order in which relocs are generated.
It is also more pleasant to read the relocs when
they are sorted.

Also, do some minor cleanup.

For #14786

Change-Id: Id92020b13fd21777dfb5b29c2722c3b2eb27001b
Reviewed-on: https://go-review.googlesource.com/20641Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Shrinks gc.Type and gc.Func slightly.

Passes "GOEXPERIMENT=fieldtrack ./all.bash" and "go test -a
-toolexec='toolstash -cmp' -ldflags=-k=rsc.io/tmp/fieldtrack.tracked
rsc.io/tmp/fieldtrack".

Change-Id: I785fe8a18eb830d9867d34247e4cd41a6a7921d4
Reviewed-on: https://go-review.googlesource.com/20557
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Split the auxFloat type into 32/64 bit versions and perform checking for
exactly representable float32 values.  Perform const folding on
float32/64.  Comment out some const negation rules that the frontend
already performs.

Change-Id: Ib3f8d59fa8b30e50fe0267786cfb3c50a06169d2
Reviewed-on: https://go-review.googlesource.com/20568
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

* Refacts a bit saving and restoring parents restrictions
* Shaves ~100k from pkg/tools/linux_amd64,
but most of the savings come from the rewrite rules.
* Improves on the following artificial test case:
func f1(a4 bool, a6 bool) bool {
  return a6 || (a6 || (a6 || a4)) || (a6 || (a4 || a6 || (false || a6)))
}

Change-Id: I714000f75a37a3a6617c6e6834c75bd23674215f
Reviewed-on: https://go-review.googlesource.com/20306Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Move functions testSchedLocalQueueLocal and testSchedLocalQueueSteal
from proc.go to export_test.go, the only site that they are used.

Fixes #14796

Change-Id: I16b6fa4a13835eab33f66a2c2e87a5f5c79b7bd3
Reviewed-on: https://go-review.googlesource.com/20640
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

readClose hasn't been used in years.

Change-Id: Ia963c082e049ef856c2a637fec15204efe48b3b6
Reviewed-on: https://go-review.googlesource.com/20631Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Ensures that after request.ParseMultipartForm has been invoked,
Request.PostForm and Request.Form are both populated with the
same formValues read in, instead of only populating Request.Form.

Fixes #9305

Change-Id: I3d4a11b006fc7dffaa35360014fe15b8c74d00a3
Reviewed-on: https://go-review.googlesource.com/19986Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Reuse auto symbols so cse can eliminate OpAddrs that refer to
them.

Change-Id: I69e6a3f77a3a33946459cf8c6eccf223f6125048
Reviewed-on: https://go-review.googlesource.com/20569
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Reduces link time by ~3%

Results with gc on:
name       old s/op   new s/op   delta
LinkCmdGo  0.82 ± 2%  0.78 ± 2%  -3.90%  (p=0.000 n=17+17)
LinkJuju   7.11 ± 7%  6.87 ± 6%  -3.41%  (p=0.012 n=20+19)

Less noisy results with gc turned off:
name       old s/op   new s/op   delta
LinkCmdGo  0.66 ± 2%  0.64 ± 2%  -3.14%  (p=0.000 n=18+20)
LinkJuju   5.91 ± 1%  5.72 ± 2%  -3.17%  (p=0.000 n=20+20)

Change-Id: I4cac7933b0b22d0aee18255e1ab54550ad364593
Reviewed-on: https://go-review.googlesource.com/20478Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>

Every go executable has COFF symbol table appended at the end. The table is
used by nm and addr2line and contains all symbols present in the executable.
The table is quite large. For example, my go.exe has 11736 records.

To generate symbol table:
1) we walk "all symbols" list to count symbols we want for the table;
2) we allocate large global array of COFFSym structs (32 bytes each)
   to fit our symbols;
3) we walk "all symbols" list again to fill our array with contents;
4) we iterate over our global array to write all records to the file.

This CL changes all these steps with single step:
- walk "all symbols" list and write each COFF symbol table record to
  the file as we go.

I hope new version is faster and uses less garbage, but I don't know
how to benchmark this.

Change-Id: Ie4870583250131ea4428e0e83a0696c9df1794e0
Reviewed-on: https://go-review.googlesource.com/20580Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>

We use *24 a lot for pointer arithmetic when accessing slices
of slices ([][]T).  Rewrite to use an LEA and a shift.
The shift will likely be free, as it often gets folded into
an indexed load/store.

Update #14606

Change-Id: Ie0bf6dc1093876efd57e88ce5f62c26a9bf21cec
Reviewed-on: https://go-review.googlesource.com/20567
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Todd Neal <todd@tneal.org>

The structpkg global variable was only used to verify internal
consistency when declaring methods during import. Track the
value in the parser and binary importer directly and pass it
to the relevant function as an argument.

Change-Id: I7e5e006f9046d84f9a3959616f073798fda36c97
Reviewed-on: https://go-review.googlesource.com/20606Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The outCount value includes a flag bit for dotdotdot.

If we have this count incorrect, then the offset for the
methodset *rtype are in the wrong place.

Fixes #14783

Change-Id: If5acb16af08d4ffe36c8c9ee389c32f2712ce757
Reviewed-on: https://go-review.googlesource.com/20566Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Currently, if a client of crypto/tls (e.g., net/http, http2) calls
tls.Conn.Write with a 33KB buffer, that ends up writing three TLS
records: 16KB, 16KB, and 1KB. Slow clients (such as 2G phones) must
download the first 16KB record before they can decrypt the first byte.
To improve latency, it's better to send smaller TLS records. However,
sending smaller records adds overhead (more overhead bytes and more
crypto calls), which slightly hurts throughput.

A simple heuristic, implemented in this change, is to send small
records for new connections, then boost to large records after the
first 1MB has been written on the connection.

Fixes #14376

Change-Id: Ice0f6279325be6775aa55351809f88e07dd700cd
Reviewed-on: https://go-review.googlesource.com/19591
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tom Bergan <tombergan@google.com>
Reviewed-by: Adam Langley <agl@golang.org>

Only copy the ones that actually change.  Also combine deep and substAny
functions into one.  The Type.Copyany field is now unused, so remove it.

Passes toolstash -cmp.

Change-Id: Id28a9bf144ecf3e522aad00496f8a21ae2b74680
Reviewed-on: https://go-review.googlesource.com/20600Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Fixes #14370.

Change-Id: Ieb95ee3494f592fb5fc74aa4b803479671816927
Reviewed-on: https://go-review.googlesource.com/20551Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

I copied this down incorrectly. See
https://tools.ietf.org/html/rfc5758#section-3.1.

Thankfully it's incredibly obscure.

Fixes #14663.

Change-Id: I4792ee979916cc15aa2e300c8bc989bc4f9c63ac
Reviewed-on: https://go-review.googlesource.com/20549Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>

This change improves the error message when encountering a TLS handshake
message that is larger than our limit (64KB). Previously the error was
just “local error: internal error”.

Updates #13401.

Change-Id: I86127112045ae33e51079e3bc047dd7386ddc71a
Reviewed-on: https://go-review.googlesource.com/20547Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Move lexinit, typeinit, lexinit1, and lexfini into new universe.go
file, and give them a more idiomatic and descriptive API. No code
changes.

Change-Id: I0e9b25dcc86ad10f4b990dc02bd33477b488cc85
Reviewed-on: https://go-review.googlesource.com/20604Reviewed-by: Robert Griesemer <gri@golang.org>

Missed these two declarations in the previous cleanup.

Change-Id: I54ff3accd387dd90e12847daccf4477169797f81
Reviewed-on: https://go-review.googlesource.com/20603
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This is really moving all the non-lexer pieces out of lex.go
into main.go. It's always been confusing that the top-most
compiler entry point (Main) is in the same file with the
lexer. Both files remain of substantial size (> 1000 lines),
which justifies this even more.

No other changes.

Change-Id: I03895589d5e3cc2340580350bbc1420539893dfc
Reviewed-on: https://go-review.googlesource.com/20601
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Id041c1b2d364aecd7a6613a53237f7de2c650a7e
Reviewed-on: https://go-review.googlesource.com/20599
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #14740

Change-Id: Iad8d971c21977b0a1f4ef55a08bb180a8125e976
Reviewed-on: https://go-review.googlesource.com/20562Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Removes an intermediate layer of functions that was clogging up a
corner of the compiler's profile graph.

I can't measure a performance improvement running a large build
like jujud, but the profile reports less total time spent in
gc.(*lexer).getr.

Change-Id: I3000585cfcb0f9729d3a3859e9023690a6528591
Reviewed-on: https://go-review.googlesource.com/20565Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

In addition to reflect.Value.Call, exported methods can be invoked
by the Func value in the reflect.Method struct. This CL has the
compiler track what functions get access to a legitimate reflect.Method
struct by looking for interface calls to either of:

	Method(int) reflect.Method
	MethodByName(string) (reflect.Method, bool)

This is a little overly conservative. If a user implements a type
with one of these methods without using the underlying calls on
reflect.Type, the linker will assume the worst and include all
exported methods. But it's cheap.

No change to any of the binary sizes reported in cl/20483.

For #14740

Change-Id: Ie17786395d0453ce0384d8b240ecb043b7726137
Reviewed-on: https://go-review.googlesource.com/20489Reviewed-by: Matthew Dempsky <mdempsky@google.com>

While we're here, remove a bit of dead code.

Change-Id: I1344bb41e5d368825ca5748189382f9e7023c59a
Reviewed-on: https://go-review.googlesource.com/20596
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Use an early return. Check errors. Deduplicate.

Change-Id: Iabefd563b5ef82a16fab4791277630804fd09003
Reviewed-on: https://go-review.googlesource.com/20597
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I298b9d389ac33a24365f4c06a122c3af989906c0
Reviewed-on: https://go-review.googlesource.com/20594
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Might as well sort them while they're still in a slice.

Change-Id: I40c25ddc5c054dcb4da2aeefa79947967609d599
Reviewed-on: https://go-review.googlesource.com/20591
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Part 1 of optimizing the deflater. This optimizes the bitwriter by:

* Removing allocations.
* Storing compound values for bit codes instead of 2 separate tables.
* Accumulate 48 bits between writes instead of 24.
* Inline bit flushing.

This also contains code that will be used in later CL's
(writeBlockDynamic, writeBlockHuff).

Tests for Huffman bit writer encoding regressions has been added.

name                       old speed      new speed      delta
EncodeDigitsSpeed1e4-4     19.3MB/s ± 1%  21.6MB/s ± 1%  +11.77%
EncodeDigitsSpeed1e5-4     25.0MB/s ± 6%  30.7MB/s ± 1%  +22.70%
EncodeDigitsSpeed1e6-4     28.2MB/s ± 1%  32.3MB/s ± 1%  +14.64%
EncodeDigitsDefault1e4-4   13.3MB/s ± 0%  14.2MB/s ± 1%   +7.07%
EncodeDigitsDefault1e5-4   6.43MB/s ± 1%  6.64MB/s ± 1%   +3.27%
EncodeDigitsDefault1e6-4   5.81MB/s ± 0%  5.85MB/s ± 1%   +0.69%
EncodeDigitsCompress1e4-4  13.2MB/s ± 0%  14.4MB/s ± 0%   +9.10%
EncodeDigitsCompress1e5-4  6.40MB/s ± 1%  6.61MB/s ± 0%   +3.20%
EncodeDigitsCompress1e6-4  5.80MB/s ± 1%  5.90MB/s ± 1%   +1.64%
EncodeTwainSpeed1e4-4      18.4MB/s ± 1%  20.7MB/s ± 1%  +12.72%
EncodeTwainSpeed1e5-4      27.7MB/s ± 1%  31.0MB/s ± 1%  +11.78%
EncodeTwainSpeed1e6-4      29.1MB/s ± 0%  32.9MB/s ± 2%  +13.25%
EncodeTwainDefault1e4-4    12.4MB/s ± 0%  13.1MB/s ± 1%   +5.88%
EncodeTwainDefault1e5-4    7.52MB/s ± 1%  7.83MB/s ± 0%   +4.19%
EncodeTwainDefault1e6-4    7.08MB/s ± 1%  7.26MB/s ± 0%   +2.54%
EncodeTwainCompress1e4-4   12.0MB/s ± 1%  12.8MB/s ± 1%   +6.70%
EncodeTwainCompress1e5-4   5.96MB/s ± 1%  6.16MB/s ± 0%   +3.27%
EncodeTwainCompress1e6-4   5.37MB/s ± 0%  5.39MB/s ± 1%   +0.47%

>Allocations:

benchmark                              old allocs     new allocs     delta
BenchmarkEncodeDigitsSpeed1e4-4        50             0              -100.00%
BenchmarkEncodeDigitsSpeed1e5-4        110            0              -100.00%
BenchmarkEncodeDigitsSpeed1e6-4        1032           0              -100.00%
BenchmarkEncodeDigitsDefault1e4-4      56             0              -100.00%
BenchmarkEncodeDigitsDefault1e5-4      120            0              -100.00%
BenchmarkEncodeDigitsDefault1e6-4      966            0              -100.00%
BenchmarkEncodeDigitsCompress1e4-4     56             0              -100.00%
BenchmarkEncodeDigitsCompress1e5-4     120            0              -100.00%
BenchmarkEncodeDigitsCompress1e6-4     966            0              -100.00%
BenchmarkEncodeTwainSpeed1e4-4         58             0              -100.00%
BenchmarkEncodeTwainSpeed1e5-4         132            0              -100.00%
BenchmarkEncodeTwainSpeed1e6-4         1082           0              -100.00%
BenchmarkEncodeTwainDefault1e4-4       52             0              -100.00%
BenchmarkEncodeTwainDefault1e5-4       126            0              -100.00%
BenchmarkEncodeTwainDefault1e6-4       886            0              -100.00%
BenchmarkEncodeTwainCompress1e4-4      52             0              -100.00%
BenchmarkEncodeTwainCompress1e5-4      120            0              -100.00%
BenchmarkEncodeTwainCompress1e6-4      880            0              -100.00%

benchmark                              old bytes     new bytes     delta
BenchmarkEncodeDigitsSpeed1e4-4        4288          2             -99.95%
BenchmarkEncodeDigitsSpeed1e5-4        8896          15            -99.83%
BenchmarkEncodeDigitsSpeed1e6-4        84098         153           -99.82%
BenchmarkEncodeDigitsDefault1e4-4      4480          3             -99.93%
BenchmarkEncodeDigitsDefault1e5-4      9216          76            -99.18%
BenchmarkEncodeDigitsDefault1e6-4      73920         768           -98.96%
BenchmarkEncodeDigitsCompress1e4-4     4480          3             -99.93%
BenchmarkEncodeDigitsCompress1e5-4     9216          76            -99.18%
BenchmarkEncodeDigitsCompress1e6-4     73920         768           -98.96%
BenchmarkEncodeTwainSpeed1e4-4         4544          2             -99.96%
BenchmarkEncodeTwainSpeed1e5-4         9600          15            -99.84%
BenchmarkEncodeTwainSpeed1e6-4         77633         153           -99.80%
BenchmarkEncodeTwainDefault1e4-4       4352          3             -99.93%
BenchmarkEncodeTwainDefault1e5-4       9408          76            -99.19%
BenchmarkEncodeTwainDefault1e6-4       65984         768           -98.84%
BenchmarkEncodeTwainCompress1e4-4      4352          3             -99.93%
BenchmarkEncodeTwainCompress1e5-4      9216          76            -99.18%
BenchmarkEncodeTwainCompress1e6-4      65792         768           -98.83%

Updates #14258

Change-Id: Ibaa97b9619743ad623094727228eb2ada1ec7f1f
Reviewed-on: https://go-review.googlesource.com/19336Reviewed-by: Nigel Tao <nigeltao@golang.org>
Reviewed-by: Joe Tsai <joetsai@digital-static.net>
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This will test if deflate output is deterministic between two runs
of the deflater, when write sizes differ.

The deflater makes no official promises that results are
deterministic between runs, but this is a good test to determine
unintentional randomness.

Note that this does not guarantee that results are deterministic
across platforms nor that results will be deterministic between
Go versions. This is also not guarantees we should imply.

Change-Id: Id7dd89fe276060fd83a43d0b34ac35d50fcd32d9
Reviewed-on: https://go-review.googlesource.com/20573Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

p can be nil in Dconv so we need to do a check before dereferencing
it. Fixes a problem I was having running toolstash.

Change-Id: I34d6d278b319583d8454c2342ac88e054fc4b641
Reviewed-on: https://go-review.googlesource.com/20595Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>