This CL adds initial support for concurrent backend compilation.

BACKGROUND

The compiler currently consists (very roughly) of the following phases:

1. Initialization.
2. Lexing and parsing into the cmd/compile/internal/syntax AST.
3. Translation into the cmd/compile/internal/gc AST.
4. Some gc AST passes: typechecking, escape analysis, inlining,
   closure handling, expression evaluation ordering (order.go),
   and some lowering and optimization (walk.go).
5. Translation into the cmd/compile/internal/ssa SSA form.
6. Optimization and lowering of SSA form.
7. Translation from SSA form to assembler instructions.
8. Translation from assembler instructions to machine code.
9. Writing lots of output: machine code, DWARF symbols,
   type and reflection info, export data.

Phase 2 was already concurrent as of Go 1.8.

Phase 3 is planned for eventual removal;
we hope to go straight from syntax AST to SSA.

Phases 5–8 are per-function; this CL adds support for
processing multiple functions concurrently.
The slowest phases in the compiler are 5 and 6,
so this offers the opportunity for some good speed-ups.

Unfortunately, it's not quite that straightforward.
In the current compiler, the latter parts of phase 4
(order, walk) are done function-at-a-time as needed.
Making order and walk concurrency-safe proved hard,
and they're not particularly slow, so there wasn't much reward.
To enable phases 5–8 to be done concurrently,
when concurrent backend compilation is requested,
we complete phase 4 for all functions
before starting later phases for any functions.

Also, in reality, we automatically generate new
functions in phase 9, such as method wrappers
and equality and has routines.
Those new functions then go through phases 4–8.
This CL disables concurrent backend compilation
after the first, big, user-provided batch of
functions has been compiled.
This is done to keep things simple,
and because the autogenerated functions
tend to be small, few, simple, and fast to compile.

USAGE

Concurrent backend compilation still defaults to off.
To set the number of functions that may be backend-compiled
concurrently, use the compiler flag -c.
In future work, cmd/go will automatically set -c.

Furthermore, this CL has been intentionally written
so that the c=1 path has no backend concurrency whatsoever,
not even spawning any goroutines.
This helps ensure that, should problems arise
late in the development cycle,
we can simply have cmd/go set c=1 always,
and revert to the original compiler behavior.

MUTEXES

Most of the work required to make concurrent backend
compilation safe has occurred over the past month.
This CL adds a handful of mutexes to get the rest of the way there;
they are the mutexes that I didn't see a clean way to avoid.
Some of them may still be eliminable in future work.

In no particular order:

* gc.funcsymsmu. The global funcsyms slice is populated
  lazily when we need function symbols for closures.
  This occurs during gc AST to SSA translation.
  The function funcsym also does a package lookup,
  which is a source of races on types.Pkg.Syms;
  funcsymsmu also covers that package lookup.
  This mutex is low priority: it adds a single global,
  it is in an infrequently used code path, and it is low contention.
  Since funcsyms may now be added in any order,
  we must sort them to preserve reproducible builds.

* gc.largeStackFramesMu. We don't discover until after SSA compilation
  that a function's stack frame is gigantic.
  Recording that error happens basically never,
  but it does happen concurrently.
  Fix with a low priority mutex and sorting.

* obj.Link.hashmu. ctxt.hash stores the mapping from
  types.Syms (compiler symbols) to obj.LSyms (linker symbols).
  It is accessed fairly heavily through all the phases.
  This is the only heavily contended mutex.

* gc.signatlistmu. The global signatlist map is
  populated with types through several of the concurrent phases,
  including notably via ngotype during DWARF generation.
  It is low priority for removal.

* gc.typepkgmu. Looking up symbols in the types package
  happens a fair amount during backend compilation
  and DWARF generation, particularly via ngotype.
  This mutex helps us to avoid a broader mutex on types.Pkg.Syms.
  It has low-to-moderate contention.

* types.internedStringsmu. gc AST to SSA conversion and
  some SSA work introduce new autotmps.
  Those autotmps have their names interned to reduce allocations.
  That interning requires protecting types.internedStrings.
  The autotmp names are heavily re-used, and the mutex
  overhead and contention here are low, so it is probably
  a worthwhile performance optimization to keep this mutex.

TESTING

I have been testing this code locally by running
'go install -race cmd/compile'
and then doing
'go build -a -gcflags=-c=128 std cmd'
for all architectures and a variety of compiler flags.
This obviously needs to be made part of the builders,
but it is too expensive to make part of all.bash.
I have filed #19962 for this.

REPRODUCIBLE BUILDS

This version of the compiler generates reproducible builds.
Testing reproducible builds also needs automation, however,
and is also too expensive for all.bash.
This is #19961.

Also of note is that some of the compiler flags used by 'toolstash -cmp'
are currently incompatible with concurrent backend compilation.
They still work fine with c=1.
Time will tell whether this is a problem.

NEXT STEPS

* Continue to find and fix races and bugs,
  using a combination of code inspection, fuzzing,
  and hopefully some community experimentation.
  I do not know of any outstanding races,
  but there probably are some.
* Improve testing.
* Improve performance, for many values of c.
* Integrate with cmd/go and fine tune.
* Support concurrent compilation with the -race flag.
  It is a sad irony that it does not yet work.
* Minor code cleanup that has been deferred during
  the last month due to uncertainty about the
  ultimate shape of this CL.

PERFORMANCE

Here's the buried lede, at last. :)

All benchmarks are from my 8 core 2.9 GHz Intel Core i7 darwin/amd64 laptop.

First, going from tip to this CL with c=1 has almost no impact.

name        old time/op       new time/op       delta
Template          195ms ± 3%        194ms ± 5%    ~     (p=0.370 n=30+29)
Unicode          86.6ms ± 3%       87.0ms ± 7%    ~     (p=0.958 n=29+30)
GoTypes           548ms ± 3%        555ms ± 4%  +1.35%  (p=0.001 n=30+28)
Compiler          2.51s ± 2%        2.54s ± 2%  +1.17%  (p=0.000 n=28+30)
SSA               5.16s ± 3%        5.16s ± 2%    ~     (p=0.910 n=30+29)
Flate             124ms ± 5%        124ms ± 4%    ~     (p=0.947 n=30+30)
GoParser          146ms ± 3%        146ms ± 3%    ~     (p=0.150 n=29+28)
Reflect           354ms ± 3%        352ms ± 4%    ~     (p=0.096 n=29+29)
Tar               107ms ± 5%        106ms ± 3%    ~     (p=0.370 n=30+29)
XML               200ms ± 4%        201ms ± 4%    ~     (p=0.313 n=29+28)
[Geo mean]        332ms             333ms       +0.10%

name        old user-time/op  new user-time/op  delta
Template          227ms ± 5%        225ms ± 5%    ~     (p=0.457 n=28+27)
Unicode           109ms ± 4%        109ms ± 5%    ~     (p=0.758 n=29+29)
GoTypes           713ms ± 4%        721ms ± 5%    ~     (p=0.051 n=30+29)
Compiler          3.36s ± 2%        3.38s ± 3%    ~     (p=0.146 n=30+30)
SSA               7.46s ± 3%        7.47s ± 3%    ~     (p=0.804 n=30+29)
Flate             146ms ± 7%        147ms ± 3%    ~     (p=0.833 n=29+27)
GoParser          179ms ± 5%        179ms ± 5%    ~     (p=0.866 n=30+30)
Reflect           431ms ± 4%        429ms ± 4%    ~     (p=0.593 n=29+30)
Tar               124ms ± 5%        123ms ± 5%    ~     (p=0.140 n=29+29)
XML               243ms ± 4%        242ms ± 7%    ~     (p=0.404 n=29+29)
[Geo mean]        415ms             415ms       +0.02%

name        old obj-bytes     new obj-bytes     delta
Template           382k ± 0%         382k ± 0%    ~     (all equal)
Unicode            203k ± 0%         203k ± 0%    ~     (all equal)
GoTypes           1.18M ± 0%        1.18M ± 0%    ~     (all equal)
Compiler          3.98M ± 0%        3.98M ± 0%    ~     (all equal)
SSA               8.28M ± 0%        8.28M ± 0%    ~     (all equal)
Flate              230k ± 0%         230k ± 0%    ~     (all equal)
GoParser           287k ± 0%         287k ± 0%    ~     (all equal)
Reflect           1.00M ± 0%        1.00M ± 0%    ~     (all equal)
Tar                190k ± 0%         190k ± 0%    ~     (all equal)
XML                416k ± 0%         416k ± 0%    ~     (all equal)
[Geo mean]         660k              660k       +0.00%

Comparing this CL to itself, from c=1 to c=2
improves real times 20-30%, costs 5-10% more CPU time,
and adds about 2% alloc.
The allocation increase comes from allocating more ssa.Caches.

name       old time/op       new time/op       delta
Template         202ms ± 3%        149ms ± 3%  -26.15%  (p=0.000 n=49+49)
Unicode         87.4ms ± 4%       84.2ms ± 3%   -3.68%  (p=0.000 n=48+48)
GoTypes          560ms ± 2%        398ms ± 2%  -28.96%  (p=0.000 n=49+49)
Compiler         2.46s ± 3%        1.76s ± 2%  -28.61%  (p=0.000 n=48+46)
SSA              6.17s ± 2%        4.04s ± 1%  -34.52%  (p=0.000 n=49+49)
Flate            126ms ± 3%         92ms ± 2%  -26.81%  (p=0.000 n=49+48)
GoParser         148ms ± 4%        107ms ± 2%  -27.78%  (p=0.000 n=49+48)
Reflect          361ms ± 3%        281ms ± 3%  -22.10%  (p=0.000 n=49+49)
Tar              109ms ± 4%         86ms ± 3%  -20.81%  (p=0.000 n=49+47)
XML              204ms ± 3%        144ms ± 2%  -29.53%  (p=0.000 n=48+45)

name       old user-time/op  new user-time/op  delta
Template         246ms ± 9%        246ms ± 4%     ~     (p=0.401 n=50+48)
Unicode          109ms ± 4%        111ms ± 4%   +1.47%  (p=0.000 n=44+50)
GoTypes          728ms ± 3%        765ms ± 3%   +5.04%  (p=0.000 n=46+50)
Compiler         3.33s ± 3%        3.41s ± 2%   +2.31%  (p=0.000 n=49+48)
SSA              8.52s ± 2%        9.11s ± 2%   +6.93%  (p=0.000 n=49+47)
Flate            149ms ± 4%        161ms ± 3%   +8.13%  (p=0.000 n=50+47)
GoParser         181ms ± 5%        192ms ± 2%   +6.40%  (p=0.000 n=49+46)
Reflect          452ms ± 9%        474ms ± 2%   +4.99%  (p=0.000 n=50+48)
Tar              126ms ± 6%        136ms ± 4%   +7.95%  (p=0.000 n=50+49)
XML              247ms ± 5%        264ms ± 3%   +6.94%  (p=0.000 n=48+50)

name       old alloc/op      new alloc/op      delta
Template        38.8MB ± 0%       39.3MB ± 0%   +1.48%  (p=0.008 n=5+5)
Unicode         29.8MB ± 0%       30.2MB ± 0%   +1.19%  (p=0.008 n=5+5)
GoTypes          113MB ± 0%        114MB ± 0%   +0.69%  (p=0.008 n=5+5)
Compiler         443MB ± 0%        447MB ± 0%   +0.95%  (p=0.008 n=5+5)
SSA             1.25GB ± 0%       1.26GB ± 0%   +0.89%  (p=0.008 n=5+5)
Flate           25.3MB ± 0%       25.9MB ± 1%   +2.35%  (p=0.008 n=5+5)
GoParser        31.7MB ± 0%       32.2MB ± 0%   +1.59%  (p=0.008 n=5+5)
Reflect         78.2MB ± 0%       78.9MB ± 0%   +0.91%  (p=0.008 n=5+5)
Tar             26.6MB ± 0%       27.0MB ± 0%   +1.80%  (p=0.008 n=5+5)
XML             42.4MB ± 0%       43.4MB ± 0%   +2.35%  (p=0.008 n=5+5)

name       old allocs/op     new allocs/op     delta
Template          379k ± 0%         378k ± 0%     ~     (p=0.421 n=5+5)
Unicode           322k ± 0%         321k ± 0%     ~     (p=0.222 n=5+5)
GoTypes          1.14M ± 0%        1.14M ± 0%     ~     (p=0.548 n=5+5)
Compiler         4.12M ± 0%        4.11M ± 0%   -0.14%  (p=0.032 n=5+5)
SSA              9.72M ± 0%        9.72M ± 0%     ~     (p=0.421 n=5+5)
Flate             234k ± 1%         234k ± 0%     ~     (p=0.421 n=5+5)
GoParser          316k ± 1%         315k ± 0%     ~     (p=0.222 n=5+5)
Reflect           980k ± 0%         979k ± 0%     ~     (p=0.095 n=5+5)
Tar               249k ± 1%         249k ± 1%     ~     (p=0.841 n=5+5)
XML               392k ± 0%         391k ± 0%     ~     (p=0.095 n=5+5)

From c=1 to c=4, real time is down ~40%, CPU usage up 10-20%, alloc up ~5%:

name       old time/op       new time/op       delta
Template         203ms ± 3%        131ms ± 5%  -35.45%  (p=0.000 n=50+50)
Unicode         87.2ms ± 4%       84.1ms ± 2%   -3.61%  (p=0.000 n=48+47)
GoTypes          560ms ± 4%        310ms ± 2%  -44.65%  (p=0.000 n=50+49)
Compiler         2.47s ± 3%        1.41s ± 2%  -43.10%  (p=0.000 n=50+46)
SSA              6.17s ± 2%        3.20s ± 2%  -48.06%  (p=0.000 n=49+49)
Flate            126ms ± 4%         74ms ± 2%  -41.06%  (p=0.000 n=49+48)
GoParser         148ms ± 4%         89ms ± 3%  -39.97%  (p=0.000 n=49+50)
Reflect          360ms ± 3%        242ms ± 3%  -32.81%  (p=0.000 n=49+49)
Tar              108ms ± 4%         73ms ± 4%  -32.48%  (p=0.000 n=50+49)
XML              203ms ± 3%        119ms ± 3%  -41.56%  (p=0.000 n=49+48)

name       old user-time/op  new user-time/op  delta
Template         246ms ± 9%        287ms ± 9%  +16.98%  (p=0.000 n=50+50)
Unicode          109ms ± 4%        118ms ± 5%   +7.56%  (p=0.000 n=46+50)
GoTypes          735ms ± 4%        806ms ± 2%   +9.62%  (p=0.000 n=50+50)
Compiler         3.34s ± 4%        3.56s ± 2%   +6.78%  (p=0.000 n=49+49)
SSA              8.54s ± 3%       10.04s ± 3%  +17.55%  (p=0.000 n=50+50)
Flate            149ms ± 6%        176ms ± 3%  +17.82%  (p=0.000 n=50+48)
GoParser         181ms ± 5%        213ms ± 3%  +17.47%  (p=0.000 n=50+50)
Reflect          453ms ± 6%        499ms ± 2%  +10.11%  (p=0.000 n=50+48)
Tar              126ms ± 5%        149ms ±11%  +18.76%  (p=0.000 n=50+50)
XML              246ms ± 5%        287ms ± 4%  +16.53%  (p=0.000 n=49+50)

name       old alloc/op      new alloc/op      delta
Template        38.8MB ± 0%       40.4MB ± 0%   +4.21%  (p=0.008 n=5+5)
Unicode         29.8MB ± 0%       30.9MB ± 0%   +3.68%  (p=0.008 n=5+5)
GoTypes          113MB ± 0%        116MB ± 0%   +2.71%  (p=0.008 n=5+5)
Compiler         443MB ± 0%        455MB ± 0%   +2.75%  (p=0.008 n=5+5)
SSA             1.25GB ± 0%       1.27GB ± 0%   +1.84%  (p=0.008 n=5+5)
Flate           25.3MB ± 0%       26.9MB ± 1%   +6.31%  (p=0.008 n=5+5)
GoParser        31.7MB ± 0%       33.2MB ± 0%   +4.61%  (p=0.008 n=5+5)
Reflect         78.2MB ± 0%       80.2MB ± 0%   +2.53%  (p=0.008 n=5+5)
Tar             26.6MB ± 0%       27.9MB ± 0%   +5.19%  (p=0.008 n=5+5)
XML             42.4MB ± 0%       44.6MB ± 0%   +5.20%  (p=0.008 n=5+5)

name       old allocs/op     new allocs/op     delta
Template          380k ± 0%         379k ± 0%   -0.39%  (p=0.032 n=5+5)
Unicode           321k ± 0%         321k ± 0%     ~     (p=0.841 n=5+5)
GoTypes          1.14M ± 0%        1.14M ± 0%     ~     (p=0.421 n=5+5)
Compiler         4.12M ± 0%        4.14M ± 0%   +0.52%  (p=0.008 n=5+5)
SSA              9.72M ± 0%        9.76M ± 0%   +0.37%  (p=0.008 n=5+5)
Flate             234k ± 1%         234k ± 1%     ~     (p=0.690 n=5+5)
GoParser          316k ± 0%         317k ± 1%     ~     (p=0.841 n=5+5)
Reflect           981k ± 0%         981k ± 0%     ~     (p=1.000 n=5+5)
Tar               250k ± 0%         249k ± 1%     ~     (p=0.151 n=5+5)
XML               393k ± 0%         392k ± 0%     ~     (p=0.056 n=5+5)

Going beyond c=4 on my machine tends to increase CPU time and allocs
without impacting real time.

The CPU time numbers matter, because when there are many concurrent
compilation processes, that will impact the overall throughput.

The numbers above are in many ways the best case scenario;
we can take full advantage of all cores.
Fortunately, the most common compilation scenario is incremental
re-compilation of a single package during a build/test cycle.

Updates #15756

Change-Id: I6725558ca2069edec0ac5b0d1683105a9fff6bea
Reviewed-on: https://go-review.googlesource.com/40693Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

When using Lstat against symlinks that point to a directory,
the function returns FileInfo with both ModeDir and ModeSymlink set.
Change that to never set ModeDir if ModeSymlink is set.

Fixes #10424
Fixes #17540
Fixes #17541

Change-Id: Iba280888aad108360b8c1f18180a24493fe7ad2b
Reviewed-on: https://go-review.googlesource.com/41830Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes golang/go#20008.

Change-Id: I7a429490320595fc558a8c5e260ec41bc3a788e2
Reviewed-on: https://go-review.googlesource.com/41858Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Taken from the Intel Software Development Manual (of course, in the line
below it's ADC DST, SRC; The opposite of the commit subject).

  12 /r		ADC r8, r/m8

We need 0x12 for the corresponding ytab line, not 0x10.

  {Ymb, Ynone, Yrb, Zm_r, 1},

Updates #14069

Change-Id: Id37cbd0c581c9988c2de355efa908956278e2189
Reviewed-on: https://go-review.googlesource.com/41857Reviewed-by: Keith Randall <khr@golang.org>

This is preparatory cleanup to make future changes clearer.

Change-Id: I20fb9c78257de61b8bd096fce6b1e751995c01f2
Reviewed-on: https://go-review.googlesource.com/41818
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I72bea1450386100482b4681b20eb9a9af12c7522
Reviewed-on: https://go-review.googlesource.com/41816Reviewed-by: Michael Matloob <matloob@golang.org>

Delete old TestRuntimeFunctionTrimming, which is testing a dead API
and is now handled in end-to-end tests.

Change-Id: I64fc2991ed4a7690456356b5f6b546f36935bb67
Reviewed-on: https://go-review.googlesource.com/41815
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

Don't bother with BenchmarkDecoderStream — it's doing something subtle
with the input buffer that isn't easy to replicate in a parallel test.

Results remain comparable with the non-parallel version with -cpu=1:

benchmark                          old ns/op     new ns/op     delta
BenchmarkCodeEncoder               22815832      21058729      -7.70%
BenchmarkCodeEncoder-6             22190561      3579757       -83.87%
BenchmarkCodeMarshal               25356621      25396429      +0.16%
BenchmarkCodeMarshal-6             25359813      4944908       -80.50%
BenchmarkCodeDecoder               94794556      88016360      -7.15%
BenchmarkCodeDecoder-6             93795028      16726283      -82.17%
BenchmarkDecoderStream             532           583           +9.59%
BenchmarkDecoderStream-6           598           550           -8.03%
BenchmarkCodeUnmarshal             97644168      89162504      -8.69%
BenchmarkCodeUnmarshal-6           96615302      17036419      -82.37%
BenchmarkCodeUnmarshalReuse        91747073      90298479      -1.58%
BenchmarkCodeUnmarshalReuse-6      89397165      15518005      -82.64%
BenchmarkUnmarshalString           808           843           +4.33%
BenchmarkUnmarshalString-6         912           220           -75.88%
BenchmarkUnmarshalFloat64          695           732           +5.32%
BenchmarkUnmarshalFloat64-6        710           191           -73.10%
BenchmarkUnmarshalInt64            635           640           +0.79%
BenchmarkUnmarshalInt64-6          618           185           -70.06%
BenchmarkIssue10335                916           947           +3.38%
BenchmarkIssue10335-6              879           216           -75.43%
BenchmarkNumberIsValid             34.7          34.3          -1.15%
BenchmarkNumberIsValid-6           34.9          36.7          +5.16%
BenchmarkNumberIsValidRegexp       1174          1121          -4.51%
BenchmarkNumberIsValidRegexp-6     1134          1119          -1.32%
BenchmarkSkipValue                 20506938      20708060      +0.98%
BenchmarkSkipValue-6               21627665      22375630      +3.46%
BenchmarkEncoderEncode             690           726           +5.22%
BenchmarkEncoderEncode-6           649           157           -75.81%

benchmark                    old MB/s     new MB/s     speedup
BenchmarkCodeEncoder         85.05        92.15        1.08x
BenchmarkCodeEncoder-6       87.45        542.07       6.20x
BenchmarkCodeMarshal         76.53        76.41        1.00x
BenchmarkCodeMarshal-6       76.52        392.42       5.13x
BenchmarkCodeDecoder         20.47        22.05        1.08x
BenchmarkCodeDecoder-6       20.69        116.01       5.61x
BenchmarkCodeUnmarshal       19.87        21.76        1.10x
BenchmarkCodeUnmarshal-6     20.08        113.90       5.67x
BenchmarkSkipValue           90.55        89.67        0.99x
BenchmarkSkipValue-6         90.83        87.80        0.97x

benchmark                    old allocs     new allocs     delta
BenchmarkIssue10335          4              4              +0.00%
BenchmarkIssue10335-6        4              4              +0.00%
BenchmarkEncoderEncode       1              1              +0.00%
BenchmarkEncoderEncode-6     1              1              +0.00%

benchmark                    old bytes     new bytes     delta
BenchmarkIssue10335          320           320           +0.00%
BenchmarkIssue10335-6        320           320           +0.00%
BenchmarkEncoderEncode       8             8             +0.00%
BenchmarkEncoderEncode-6     8             8             +0.00%

updates #18177

Change-Id: Ia4f5bf5ac0afbadb1705ed9f9e1b39dabba67b40
Reviewed-on: https://go-review.googlesource.com/36724Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Add a benchmark for PtrTo: it's the motivation for #17973, which is
the motivation for #18177.

Results remain comparable with the non-parallel version with -cpu=1:

benchmark                             old ns/op     new ns/op     delta
BenchmarkCall                         357           360           +0.84%
BenchmarkCall-6                       90.3          90.7          +0.44%
BenchmarkCallArgCopy/size=128         319           323           +1.25%
BenchmarkCallArgCopy/size=128-6       329           82.2          -75.02%
BenchmarkCallArgCopy/size=256         354           335           -5.37%
BenchmarkCallArgCopy/size=256-6       340           85.2          -74.94%
BenchmarkCallArgCopy/size=1024        374           703           +87.97%
BenchmarkCallArgCopy/size=1024-6      378           95.8          -74.66%
BenchmarkCallArgCopy/size=4096        627           631           +0.64%
BenchmarkCallArgCopy/size=4096-6      643           120           -81.34%
BenchmarkCallArgCopy/size=65536       10502         10169         -3.17%
BenchmarkCallArgCopy/size=65536-6     10298         2240          -78.25%
BenchmarkFieldByName1                 139           132           -5.04%
BenchmarkFieldByName1-6               144           24.9          -82.71%
BenchmarkFieldByName2                 2721          2778          +2.09%
BenchmarkFieldByName2-6               3953          578           -85.38%
BenchmarkFieldByName3                 19136         18357         -4.07%
BenchmarkFieldByName3-6               23072         3850          -83.31%
BenchmarkInterfaceBig                 12.7          15.5          +22.05%
BenchmarkInterfaceBig-6               14.2          2.48          -82.54%
BenchmarkInterfaceSmall               13.1          15.1          +15.27%
BenchmarkInterfaceSmall-6             13.0          2.54          -80.46%
BenchmarkNew                          43.8          43.0          -1.83%
BenchmarkNew-6                        40.5          6.67          -83.53%

benchmark                             old MB/s     new MB/s     speedup
BenchmarkCallArgCopy/size=128         400.24       395.15       0.99x
BenchmarkCallArgCopy/size=128-6       388.74       1557.76      4.01x
BenchmarkCallArgCopy/size=256         722.44       762.44       1.06x
BenchmarkCallArgCopy/size=256-6       751.98       3003.83      3.99x
BenchmarkCallArgCopy/size=1024        2733.22      1455.50      0.53x
BenchmarkCallArgCopy/size=1024-6      2706.40      10687.53     3.95x
BenchmarkCallArgCopy/size=4096        6523.32      6488.25      0.99x
BenchmarkCallArgCopy/size=4096-6      6363.85      34003.09     5.34x
BenchmarkCallArgCopy/size=65536       6239.88      6444.46      1.03x
BenchmarkCallArgCopy/size=65536-6     6363.83      29255.26     4.60x

benchmark           old allocs     new allocs     delta
BenchmarkCall       0              0              +0.00%
BenchmarkCall-6     0              0              +0.00%

benchmark           old bytes     new bytes     delta
BenchmarkCall       0             0             +0.00%
BenchmarkCall-6     0             0             +0.00%

updates #17973
updates #18177

Change-Id: If70c5c742e8d1b138347f4963ad7cff38fffc018
Reviewed-on: https://go-review.googlesource.com/36831
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Results remain comparable with the non-parallel version with -cpu=1:

benchmark                              old ns/op     new ns/op     delta
BenchmarkEndToEndPipe                  6200          6171          -0.47%
BenchmarkEndToEndPipe-6                1073          1024          -4.57%
BenchmarkEndToEndByteBuffer            2925          2664          -8.92%
BenchmarkEndToEndByteBuffer-6          516           560           +8.53%
BenchmarkEndToEndSliceByteBuffer       231683        237450        +2.49%
BenchmarkEndToEndSliceByteBuffer-6     59080         59452         +0.63%
BenchmarkEncodeComplex128Slice         67541         66003         -2.28%
BenchmarkEncodeComplex128Slice-6       72740         11316         -84.44%
BenchmarkEncodeFloat64Slice            25769         27899         +8.27%
BenchmarkEncodeFloat64Slice-6          26655         4557          -82.90%
BenchmarkEncodeInt32Slice              18685         18845         +0.86%
BenchmarkEncodeInt32Slice-6            18389         3462          -81.17%
BenchmarkEncodeStringSlice             19089         19354         +1.39%
BenchmarkEncodeStringSlice-6           20155         3237          -83.94%
BenchmarkEncodeInterfaceSlice          659601        677129        +2.66%
BenchmarkEncodeInterfaceSlice-6        640974        251621        -60.74%
BenchmarkDecodeComplex128Slice         117130        129955        +10.95%
BenchmarkDecodeComplex128Slice-6       155447        24924         -83.97%
BenchmarkDecodeFloat64Slice            67695         68776         +1.60%
BenchmarkDecodeFloat64Slice-6          82966         15225         -81.65%
BenchmarkDecodeInt32Slice              63102         62733         -0.58%
BenchmarkDecodeInt32Slice-6            77857         13003         -83.30%
BenchmarkDecodeStringSlice             130240        129562        -0.52%
BenchmarkDecodeStringSlice-6           165500        31507         -80.96%
BenchmarkDecodeInterfaceSlice          937637        1060835       +13.14%
BenchmarkDecodeInterfaceSlice-6        973495        270613        -72.20%

updates #18177

Change-Id: Ib3579010faa70827d5cbd02a826dbbb66ca13eb7
Reviewed-on: https://go-review.googlesource.com/36722
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Results remain comparable with the non-parallel version with -cpu=1:
benchmark                old ns/op     new ns/op     delta
BenchmarkMarshal         31220         28618         -8.33%
BenchmarkMarshal-6       37181         7658          -79.40%
BenchmarkUnmarshal       81837         83522         +2.06%
BenchmarkUnmarshal-6     96339         18244         -81.06%

benchmark                old allocs     new allocs     delta
BenchmarkMarshal         23             23             +0.00%
BenchmarkMarshal-6       23             23             +0.00%
BenchmarkUnmarshal       189            189            +0.00%
BenchmarkUnmarshal-6     189            189            +0.00%

benchmark                old bytes     new bytes     delta
BenchmarkMarshal         5776          5776          +0.00%
BenchmarkMarshal-6       5776          5776          +0.00%
BenchmarkUnmarshal       8576          8576          +0.00%
BenchmarkUnmarshal-6     8576          8576          +0.00%

updates #18177

Change-Id: I7e7055a11d18896bd54d7d773f2ec64767cdb4c8
Reviewed-on: https://go-review.googlesource.com/36810
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This is a direct port of the version from
commit a60ad46e0ed33d02e09bda439efaf9c9727dbc6c
(https://go-review.googlesource.com/c/37342/).

updates #17973
updates #18177

Change-Id: I63fa5ef6951b1edd39f84927d1181a4df9b15385
Reviewed-on: https://go-review.googlesource.com/36617Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Follow-up to review comments on CL 41797.

Mask the input to set2 and set3, so that at the very least,
we won't corrupt the rest of the flags in case of a bad input.
It also seems more semantically appropriate.

Do minor cleanup in addrescapes. I started on larger cleanup,
but it wasn't clear that it was an improvement.

Add warning comments and sanity checks to Initorder and Class constants,
to attempt to prevent them from overflowing their allotted flag bits.

Passes toolstash-check.

Change-Id: I57b9661ba36f56406aa7a1d8da9b7c70338f9119
Reviewed-on: https://go-review.googlesource.com/41817
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

When the stack register is decremented to acquire stack space at
the beginning of a function, a MOVDU should be used so it is done
atomically, unless the size of the stack frame is too large for
that instruction.  The code to determine whether to use MOVDU
or MOVD was checking if the function was a leaf and always generating MOVD
when it was.  The choice of MOVD vs. MOVDU should only depend on the stack
frame size.  This fixes that problem.

Change-Id: I0e49c79036f1e8f7584179e1442b938fc6da085f
Reviewed-on: https://go-review.googlesource.com/41813Reviewed-by: Michael Munday <munday@ca.ibm.com>

Put it at position zero, since it is fairly hot.

This shrinks gc.Node into a smaller size class on 64 bit systems.

name        old time/op       new time/op       delta
Template          193ms ± 5%        192ms ± 3%    ~     (p=0.353 n=94+93)
Unicode          86.1ms ± 5%       85.0ms ± 4%  -1.23%  (p=0.000 n=95+98)
GoTypes           546ms ± 3%        544ms ± 4%  -0.40%  (p=0.007 n=94+97)
Compiler          2.56s ± 3%        2.54s ± 3%  -0.67%  (p=0.000 n=99+97)
SSA               5.13s ± 2%        5.10s ± 3%  -0.55%  (p=0.000 n=94+98)
Flate             122ms ± 6%        121ms ± 4%  -0.75%  (p=0.002 n=97+95)
GoParser          144ms ± 5%        144ms ± 4%    ~     (p=0.298 n=98+97)
Reflect           348ms ± 4%        349ms ± 4%    ~     (p=0.350 n=98+97)
Tar               105ms ± 5%        104ms ± 5%    ~     (p=0.154 n=96+98)
XML               200ms ± 5%        198ms ± 4%  -0.71%  (p=0.015 n=97+98)
[Geo mean]        330ms             328ms       -0.52%

name        old user-time/op  new user-time/op  delta
Template          229ms ±11%        224ms ± 7%  -2.16%  (p=0.001 n=100+87)
Unicode           109ms ± 5%        109ms ± 6%    ~     (p=0.897 n=96+91)
GoTypes           712ms ± 4%        709ms ± 4%    ~     (p=0.085 n=96+98)
Compiler          3.41s ± 3%        3.36s ± 3%  -1.43%  (p=0.000 n=98+98)
SSA               7.46s ± 3%        7.31s ± 3%  -2.02%  (p=0.000 n=100+99)
Flate             145ms ± 6%        143ms ± 6%  -1.11%  (p=0.001 n=99+97)
GoParser          177ms ± 5%        176ms ± 5%  -0.78%  (p=0.018 n=95+95)
Reflect           432ms ± 7%        435ms ± 9%    ~     (p=0.296 n=100+100)
Tar               121ms ± 7%        121ms ± 5%    ~     (p=0.072 n=100+95)
XML               241ms ± 4%        239ms ± 5%    ~     (p=0.085 n=97+99)
[Geo mean]        413ms             410ms       -0.73%

name        old alloc/op      new alloc/op      delta
Template         38.4MB ± 0%       37.7MB ± 0%  -1.85%  (p=0.008 n=5+5)
Unicode          30.1MB ± 0%       28.8MB ± 0%  -4.09%  (p=0.008 n=5+5)
GoTypes           112MB ± 0%        110MB ± 0%  -1.69%  (p=0.008 n=5+5)
Compiler          470MB ± 0%        461MB ± 0%  -1.91%  (p=0.008 n=5+5)
SSA              1.13GB ± 0%       1.11GB ± 0%  -1.70%  (p=0.008 n=5+5)
Flate            25.0MB ± 0%       24.6MB ± 0%  -1.67%  (p=0.008 n=5+5)
GoParser         31.6MB ± 0%       31.1MB ± 0%  -1.66%  (p=0.008 n=5+5)
Reflect          77.1MB ± 0%       75.8MB ± 0%  -1.69%  (p=0.008 n=5+5)
Tar              26.3MB ± 0%       25.7MB ± 0%  -2.06%  (p=0.008 n=5+5)
XML              41.9MB ± 0%       41.1MB ± 0%  -1.93%  (p=0.008 n=5+5)
[Geo mean]       73.5MB            72.0MB       -2.03%

name        old allocs/op     new allocs/op     delta
Template           383k ± 0%         383k ± 0%    ~     (p=0.690 n=5+5)
Unicode            343k ± 0%         343k ± 0%    ~     (p=0.841 n=5+5)
GoTypes           1.16M ± 0%        1.16M ± 0%    ~     (p=0.310 n=5+5)
Compiler          4.43M ± 0%        4.42M ± 0%  -0.17%  (p=0.008 n=5+5)
SSA               9.85M ± 0%        9.85M ± 0%    ~     (p=0.310 n=5+5)
Flate              236k ± 0%         236k ± 1%    ~     (p=0.841 n=5+5)
GoParser           320k ± 0%         320k ± 0%    ~     (p=0.421 n=5+5)
Reflect            988k ± 0%         987k ± 0%    ~     (p=0.690 n=5+5)
Tar                252k ± 0%         251k ± 0%    ~     (p=0.095 n=5+5)
XML                399k ± 0%         399k ± 0%    ~     (p=1.000 n=5+5)
[Geo mean]         741k              740k       -0.07%

Change-Id: I9e952b58a98e30a12494304db9ce50d0a85e459c
Reviewed-on: https://go-review.googlesource.com/41797
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>

In many cases the records returned by Reader.Read will only be used between calls
to Read and become garbage once a new record is read. In this case, instead of
allocating a new slice on each call to Read, we can reuse the last allocated slice
for successive calls to avoid unnecessary allocations.

This change adds a new field ReuseRecord to the Reader struct to enable this reuse.

ReuseRecord is false by default to avoid breaking existing code which dependss on
the current behaviour.

I also added 4 new benchmarks, corresponding to the existing Read benchmarks, which
set ReuseRecord to true.

Benchstat on my local machine (old is ReuseRecord = false, new is ReuseRecord = true)

name                          old time/op    new time/op    delta
Read-8                          2.75µs ± 2%    1.88µs ± 1%  -31.52%  (p=0.000 n=14+15)
ReadWithFieldsPerRecord-8       2.75µs ± 0%    1.89µs ± 1%  -31.43%  (p=0.000 n=13+13)
ReadWithoutFieldsPerRecord-8    2.77µs ± 1%    1.88µs ± 1%  -32.06%  (p=0.000 n=15+15)
ReadLargeFields-8               55.4µs ± 1%    54.2µs ± 0%   -2.07%  (p=0.000 n=15+14)

name                          old alloc/op   new alloc/op   delta
Read-8                            664B ± 0%       24B ± 0%  -96.39%  (p=0.000 n=15+15)
ReadWithFieldsPerRecord-8         664B ± 0%       24B ± 0%  -96.39%  (p=0.000 n=15+15)
ReadWithoutFieldsPerRecord-8      664B ± 0%       24B ± 0%  -96.39%  (p=0.000 n=15+15)
ReadLargeFields-8               3.94kB ± 0%    2.98kB ± 0%  -24.39%  (p=0.000 n=15+15)

name                          old allocs/op  new allocs/op  delta
Read-8                            18.0 ± 0%       8.0 ± 0%  -55.56%  (p=0.000 n=15+15)
ReadWithFieldsPerRecord-8         18.0 ± 0%       8.0 ± 0%  -55.56%  (p=0.000 n=15+15)
ReadWithoutFieldsPerRecord-8      18.0 ± 0%       8.0 ± 0%  -55.56%  (p=0.000 n=15+15)
ReadLargeFields-8                 24.0 ± 0%      12.0 ± 0%  -50.00%  (p=0.000 n=15+15)

Fixes #19721

Change-Id: I79b14128bb9bb3465f53f40f93b1b528a9da6f58
Reviewed-on: https://go-review.googlesource.com/41730Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Some large testing/build systems require some form of test discovery before
running tests.  This usually allows for analytics, history, and stats on a per
tests basis.  Typically these systems are meant used in multi-language
environments and the original source code is not known or available.

This adds a -test.list option which takes a regular expression as an
argument. Any tests, benchmarks, or examples that match that regular
expression will be printed, one per line, to stdout and then the program
will exit.

Since subtests are named/discovered at run time this will only show
top-level tests names and is a known limitation.

Fixes #17209

Change-Id: I7e607f5f4f084d623a1cae88a1f70e7d92b7f13e
Reviewed-on: https://go-review.googlesource.com/41195Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The Context definition to date has not defined what Err returns
before the Done channel is closed. Define that it returns nil,
as most implementations do.

All the standard context implementations (those in package
context and in golang.org/x/net/context) return Err() == nil
when Done is not yet closed. However, some non-standard
implementations may exist that return Err() != nil in this case,
as permitted by the Context definition before this date.
Call these "errorful implementations".

Because all the standard context implementations ensure that
Err() == nil when Done is not yet closed, clients now exist that
assume Err() != nil implies Done is closed and use calling Err
as a quick short-circuit check instead of first doing a non-blocking
receive from Done and then, if that succeeds, needing to call Err.
This assumption holds for all the standard Context implementations,
so these clients work fine in practice, even though they are making
unwarranted assumptions about the Context implementations.
Call these "technically incorrect clients".

If a technically incorrect client encounters an errorful
implementation, the client misbehaves. Because there are few
errorful implementations, over time we expect that many clients
will end up being technically incorrect without realizing it,
leading to latent, subtle bugs. If we want to eliminate these
latent, subtle bugs, there are two ways to do this:
either make errorful implementations more common
(exposing the client bugs more often) or redefine the Context
interface so that the clients are not buggy after all.

If we make errorful implementations more common, such
as by changing the standard context implementations to
return ErrNotDone instead of nil when Err is called before
Done is closed, this will shake out essentially all of the
technically incorrect clients, forcing people to find and fix
those clients during the transition to Go 1.9.
Technically this is allowed by the compatibility policy,
but we expect there are many pieces of code assuming
that Err() != nil means done, so updating will cause real pain.

If instead we disallow errorful implementations, then they
will need to be fixed as they are discovered, but the fault
will officially lie in the errorful Context implementation,
not in the clients. Technically this is disallowed by the compatibility
policy, because these errorful implementations were "correct"
in earlier versions of Go, except that they didn't work with
common client code. We expect there are hardly any errorful
implementations, so that disallowing them will be less disruptive
and more in the spirit of the compatibility policy.

This CL takes the path of expected least disruption,
narrowing the Context interface semantics and potentially
invalidating existing implementations. A survey of the
go-corpus v0.01 turned up only five Context implementations,
all trivial and none errorful (details in #19856).
We are aware of one early Context implementation inside Google,
from before even golang.org/x/net/context existed,
that is errorful. The misbehavior of an open-source library
when passed such a context is what prompted #19856.
That context implementation would be disallowed after this CL
and would need to be corrected. We are aware of no other
affected context implementations. On the other hand, a survey
of the go-corpus v0.01 turned up many instances of client
code assuming that Err() == nil implies not done yet
(details also in #19856). On balance, narrowing Context and
thereby allowing Err() == nil checks should invalidate significantly
less code than a push to flush out all the currently technically
incorrect Err() == nil checks.

If release feedback shows that we're wrong about this balance,
we can roll back this CL and try again in Go 1.10.

Fixes #19856.

Change-Id: Id45d126fac70e1fcc42d73e5a87ca1b66935b831
Reviewed-on: https://go-review.googlesource.com/40291
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Sameer Ajmani <sameer@golang.org>

Since close errors have been cleaned up in CL 39997,
TestCloseError is failing on Plan 9, because
TCPListener.Close didn't check that the listener
has already been closed before writing the "hangup"
string to the listener control file.

This change fixes TCPListener.Close on Plan 9,
by closing poll.FD before writing the "hangup"
string.

Fixes #20128.

Change-Id: I13862b23a9055dd1be658acef7066707d98c591f
Reviewed-on: https://go-review.googlesource.com/41850
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I251ae497b0ab237d4b3fe98e397052394142d437
Reviewed-on: https://go-review.googlesource.com/41653Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This updates sha256.block and sha512.block to use vector instructions.  While
each round must still be performed independently, this allows for the use of
the vshasigma{w,d} crypto acceleration instructions.

For crypto/sha256:

benchmark               old ns/op     new ns/op     delta
BenchmarkHash8Bytes     570           300           -47.37%
BenchmarkHash1K         7529          3018          -59.91%
BenchmarkHash8K         55308         21938         -60.33%

benchmark               old MB/s     new MB/s     speedup
BenchmarkHash8Bytes     14.01        26.58        1.90x
BenchmarkHash1K         136.00       339.23       2.49x
BenchmarkHash8K         148.11       373.40       2.52x

For crypto/sha512:

benchmark               old ns/op     new ns/op     delta
BenchmarkHash8Bytes     725           394           -45.66%
BenchmarkHash1K         5062          2107          -58.38%
BenchmarkHash8K         34711         13918         -59.90%

benchmark               old MB/s     new MB/s     speedup
BenchmarkHash8Bytes     11.03        20.29        1.84x
BenchmarkHash1K         202.28       485.84       2.40x
BenchmarkHash8K         236.00       588.56       2.49x

Fixes #20069

Change-Id: I28bffe6e9eb484a83a004116fce84acb4942abca
Reviewed-on: https://go-review.googlesource.com/41391
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>

This may improve perormance during concurrent access
to mheap.central array from multiple CPU cores.

Change-Id: I8f48dd2e72aa62e9c32de07ae60fe552d8642782
Reviewed-on: https://go-review.googlesource.com/41550Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Moved the relevant file.close() usages close to after the
file opens and put them in defer statements, so that readers
don't have to think too much as to where the file is
being closed.

Change-Id: Ic4190b02ea2f5ac281b9ba104e0023e9f87ca8c7
Reviewed-on: https://go-review.googlesource.com/41796Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Catch all the cases where a file operation might return ErrFileClosing,
and convert to ErrClosed. Use a new method for the conversion, which
permits us to remove some KeepAlive calls.

Change-Id: I584178f297efe6cb86f3090b2341091b412f1041
Reviewed-on: https://go-review.googlesource.com/41793
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Id5aa4a1499068bf2d3497b21d794f970b7e47fdf
Reviewed-on: https://go-review.googlesource.com/41795
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Grand savings: 6 bits.

Change-Id: I364be54cc41534689e01672ed0fe2c10a560d3d4
Reviewed-on: https://go-review.googlesource.com/41794
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I30c59ba84dcacc3de39c42f94484b47bb7c36eba
Reviewed-on: https://go-review.googlesource.com/41792
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Resolve import paths to get plugin symbol prefixes.

Fixes #19534

Change-Id: Ic25d83e72465ba8f6be0337218a1627b5dc702dc
Reviewed-on: https://go-review.googlesource.com/40994
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

The LocalAddrContext should have the network address of the actual
interface.

Fixes #18686

Change-Id: I9c401eda312f3a0e7e65b013af827aeeef3b4d3d
Reviewed-on: https://go-review.googlesource.com/35490
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Node.Walkdef is 0, 1, or 2, so it only requires two bits.
Add support for 2-bit values to bitset,
and use it for Node.Walkdef.

Class, Embedded, Typecheck, and Initorder will follow suit
in subsequent CLs.

The multi-bit flags will go at the beginning,
since that generates (marginally) more efficient code.

Change-Id: Id6e2e66e437f10aaa05b8a6e1652efb327d06128
Reviewed-on: https://go-review.googlesource.com/41791
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

It is no longer used.

Change-Id: Id64f387867a0503d13eaecda12e6606682c24595
Reviewed-on: https://go-review.googlesource.com/41790
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

In the past we returned "use of closed network connection" when using
a closed network descriptor in some way. In CL 36799 that was changed
to return "use of closed file or network connection". Because programs
have no access to a value of this error type (see issue #4373) they
resort to doing direct string comparisons (see issue #19252). This CL
restores the old error string so that we don't break programs
unnecessarily with the 1.9 release.

This adds a test to the net package for the expected string.

For symmetry check that the os package returns the expected error,
which for os already exists as os.ErrClosed.

Updates #4373.
Fixed #19252.

Change-Id: I5b83fd12cfa03501a077cad9336499b819f4a38b
Reviewed-on: https://go-review.googlesource.com/39997
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

In addition to being more compact,
this makes the code a lot clearer.

Change-Id: Ibcb70526c2e5913dcf34904fda194e3585228c3f
Reviewed-on: https://go-review.googlesource.com/41761
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

node.Likely may once have held -1/0/+1,
but it is now only 0/1.

With improved SSA heuristics,
it may someday go away entirely.

Change-Id: I6451d17fd7fb47e67fea4d39df302b6db00ea57b
Reviewed-on: https://go-review.googlesource.com/41760
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

It was added in Go 1.7. Also gofmt while at it.

Change-Id: Idb65fb44e2f2a4365dceea3f833aeb51a8d12333
Reviewed-on: https://go-review.googlesource.com/41692
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates #18243

Change-Id: I1fe0af65dbd52c3e8e0a245e4cbbdfca100971b4
Reviewed-on: https://go-review.googlesource.com/41759
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

This updates the bundled http2 package from git rev
5602c733f70afc6dcec6766be0d5034d4c4f14de of the x/net repo for:

  http2: Use NO_ERROR instead of CANCEL when responding before the request is finished
  https://golang.org/cl/40630

  http2: enforce write deadline per stream
  https://golang.org/cl/34727

Updates golang/go#19948
Fixes golang/go#18437

Change-Id: I14500476e91551fa8f27a1aeb8ae3cac9600b74c
Reviewed-on: https://go-review.googlesource.com/41753Reviewed-by: Kale Blankenship <kale@lemnisys.com>
Reviewed-by: Tom Bergan <tombergan@google.com>
Run-TryBot: Kale Blankenship <kale@lemnisys.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates golang_org/x/net/route to rev da118f7 for:
- route: don't fail test when at least one version of INET protocols is available

Updates #19298.
Updates #19967.

Change-Id: I46948f1bd4ac6e6afd424623233f90e2b6b954c6
Reviewed-on: https://go-review.googlesource.com/41652
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates golang_org/x/net/lif to rev a25ba90 for:
- lif: don't fail test when at least one version of INET protocols is available

Updates #19967.

Change-Id: I4b946a4c6eee7938193688ecbfc4a9d69d88c94e
Reviewed-on: https://go-review.googlesource.com/41651
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I34547b057605bb9e1e2227c41867589348560244
Reviewed-on: https://go-review.googlesource.com/41513
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>