I've placed net.runtime_Semacquire into netpoll.goc,
but netbsd does not yet use netpoll.goc.

R=golang-dev, bradfitz, iant
CC=golang-dev
https://golang.org/cl/12699045

The mutex, fdMutex, handles locking and lifetime of sysfd,
and serializes Read and Write methods.
This allows to strip 2 sync.Mutex.Lock calls,
2 sync.Mutex.Unlock calls, 1 defer and some amount
of misc overhead from every network operation.

On linux/amd64, Intel E5-2690:
benchmark                             old ns/op    new ns/op    delta
BenchmarkTCP4Persistent                    9595         9454   -1.47%
BenchmarkTCP4Persistent-2                  8978         8772   -2.29%
BenchmarkTCP4ConcurrentReadWrite           4900         4625   -5.61%
BenchmarkTCP4ConcurrentReadWrite-2         2603         2500   -3.96%

In general it strips 70-500 ns from every network operation depending
on processor model. On my relatively new E5-2690 it accounts to ~5%
of network op cost.

Fixes #6074.

R=golang-dev, bradfitz, alex.brainman, iant, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/12418043

The old code was caching per-type struct field info. Instead,
cache type-specific encoding funcs, tailored for that
particular type to avoid unnecessary reflection at runtime.
Once the machine is built once, future encodings of that type
just run the func.

benchmark               old ns/op    new ns/op    delta
BenchmarkCodeEncoder     48424939     36975320  -23.64%

benchmark                old MB/s     new MB/s  speedup
BenchmarkCodeEncoder        40.07        52.48    1.31x

Additionally, the numbers seem stable now at ~52 MB/s, whereas
the numbers for the old code were all over the place: 11 MB/s,
40 MB/s, 13 MB/s, 39 MB/s, etc.  In the benchmark above I compared
against the best I saw the old code do.

R=rsc, adg
CC=gobot, golang-dev, r
https://golang.org/cl/9129044

This should be more efficient everywhere, and appears to be
required on Solaris.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12583046

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12578044

bug086.go:14:1: error: missing return at end of function

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12697043

Sigh.

R=golang-dev
CC=golang-dev
https://golang.org/cl/12491045

Simple approach. Still generates garbage, but not as much.

benchmark                        old ns/op    new ns/op    delta
BenchmarkWriteSlice1000Int32s        40260        18791  -53.33%

benchmark                         old MB/s     new MB/s  speedup
BenchmarkWriteSlice1000Int32s        99.35       212.87    2.14x

Fixes #2634.

R=golang-dev, crawshaw
CC=golang-dev
https://golang.org/cl/12680046

Fixes #5048.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12651044

Introduce freezetheworld function that is a best-effort attempt to stop any concurrently running goroutines. Call it during crash.
Fixes #5873.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12054044

It's a modest package with modest goals and limitations.
Make that clear.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/12694043

No longer continue assuming package main.

Fixes #4776.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12677043

Original CL by rsc (11916045):

The motivation for disallowing them was RFC 4180 saying
"The last field in the record must not be followed by a comma."
I believe this is an admonition to CSV generators, not readers.
When reading, anything followed by a comma is not the last field.

Fixes #5892.

R=golang-dev, rsc, r
CC=golang-dev
https://golang.org/cl/12294043

Pseudo-instructions MOVBS and MOVHS are used to clarify
the semantics of short integers vs. registers:
 * 8-bit and 16-bit values in registers are assumed to always
   be zero-extended or sign-extended depending on their type.
 * MOVB is truncation or move of an already extended value
   between registers.
 * MOVBU enforces zero-extension at the destination (register).
 * MOVBS enforces sign-extension at the destination (register).
And similarly for MOVH/MOVS/MOVHU.

The linker is adapted to assemble MOVB and MOVH to an ordinary
mov. Also a peephole pass in 5g that aims at eliminating
redundant zero/sign extensions is improved.

encoding/binary:
benchmark                              old ns/op    new ns/op    delta
BenchmarkReadSlice1000Int32s              220387       217185   -1.45%
BenchmarkReadStruct                        12839        12910   +0.55%
BenchmarkReadInts                           5692         5534   -2.78%
BenchmarkWriteInts                          6137         6016   -1.97%
BenchmarkPutUvarint32                        257          241   -6.23%
BenchmarkPutUvarint64                        812          754   -7.14%
benchmark                               old MB/s     new MB/s  speedup
BenchmarkReadSlice1000Int32s               18.15        18.42    1.01x
BenchmarkReadStruct                         5.45         5.42    0.99x
BenchmarkReadInts                           5.27         5.42    1.03x
BenchmarkWriteInts                          4.89         4.99    1.02x
BenchmarkPutUvarint32                      15.56        16.57    1.06x
BenchmarkPutUvarint64                       9.85        10.60    1.08x

crypto/des:
benchmark                              old ns/op    new ns/op    delta
BenchmarkEncrypt                            7002         5169  -26.18%
BenchmarkDecrypt                            7015         5195  -25.94%
benchmark                               old MB/s     new MB/s  speedup
BenchmarkEncrypt                            1.14         1.55    1.36x
BenchmarkDecrypt                            1.14         1.54    1.35x

strconv:
benchmark                              old ns/op    new ns/op    delta
BenchmarkAtof64Decimal                       457          385  -15.75%
BenchmarkAtof64Float                         574          479  -16.55%
BenchmarkAtof64FloatExp                     1035          906  -12.46%
BenchmarkAtof64Big                          1793         1457  -18.74%
BenchmarkAtof64RandomBits                   2267         2066   -8.87%
BenchmarkAtof64RandomFloats                 1416         1194  -15.68%
BenchmarkAtof32Decimal                       451          379  -15.96%
BenchmarkAtof32Float                         547          435  -20.48%
BenchmarkAtof32FloatExp                     1095          986   -9.95%
BenchmarkAtof32Random                       1154         1006  -12.82%
BenchmarkAtoi                               1415         1380   -2.47%
BenchmarkAtoiNeg                            1414         1401   -0.92%
BenchmarkAtoi64                             1744         1671   -4.19%
BenchmarkAtoi64Neg                          1737         1662   -4.32%

Fixes #1837.

R=rsc, dave, bradfitz
CC=golang-dev
https://golang.org/cl/12424043

Fixes #6043.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12693043

Fixes #6034.

R=golang-dev, bradfitz, alex.brainman, dan.kortschak
CC=golang-dev
https://golang.org/cl/12311044

By separating finding the end of the comment from the end of the action,
we can diagnose malformed comments better.
Also tweak the documentation to make the comment syntax clearer.

Fixes #6022.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/12570044

g% 6c ~/x.c
/Users/rsc/x.c:1 duplicate types given: STRUCT s and VOID
/Users/rsc/x.c:1 no return at end of function: f
g%

Fixes #6083.

R=ken2
CC=golang-dev
https://golang.org/cl/12691043

See issue 4949 for a full explanation.

Allocs go from 1 to zero in the non-addressable case.
Fixes #4949.

BenchmarkInterfaceBig             90           14  -84.01%
BenchmarkInterfaceSmall           14           14   +0.00%

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12646043

R=golang-dev, bradfitz
CC=golang-dev, ryanslade
https://golang.org/cl/12588044

Unlike the existing net package own pollster, runtime-integrated
network pollster on BSD variants, actually kqueue, requires a socket
that has beed passed to syscall.Listen previously for a stream
listener.

This CL separates pollDesc.Init of Unix network pollster from newFD
to avoid any breakages in the transition from Unix network pollster
to runtime-integrated pollster. Upcoming CLs will rearrange the call
order of pollster and syscall functions like the following;

- For dialers that open active connections, pollDesc.Init will be
  called in between syscall.Bind and syscall.Connect.

- For stream listeners that open passive stream connections,
  pollDesc.Init will be called just after syscall.Listen.

- For datagram listeners that open datagram connections,
  pollDesc.Init will be called just after syscall.Bind.

This is in preparation for runtime-integrated network pollster for BSD
variants.

Update #5199

R=dvyukov, bradfitz
CC=golang-dev
https://golang.org/cl/12663043

Having a trailing dot in the string doesn't really simplify
the checking loop in isDomainName. Avoid this unnecessary allocation.
Also make the valid domain names more explicit by adding some more
test cases.

benchmark            old ns/op    new ns/op    delta
BenchmarkDNSNames       2420.0        983.0  -59.38%

benchmark           old allocs   new allocs    delta
BenchmarkDNSNames           12            0  -100.00%

benchmark            old bytes    new bytes    delta
BenchmarkDNSNames          336            0  -100.00%

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12662043

Renders code coverage as an overlay, replicating the look of the
HTML that go tool cover produces.

Also some cleanups.

R=adonovan, bradfitz
CC=golang-dev
https://golang.org/cl/12684043

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/12603045

MOVBS and MOVHS are defined as duplicates of MOVB and MOVH,
and perform sign-extension moving.
No change is made to code generation.

Update #1837

R=rsc, bradfitz
CC=golang-dev
https://golang.org/cl/12682043

- adjusted test files so that they actually type-check
- adjusted go1.txt, go1.1.txt, next.txt
- to run, provide build tag: api_tool

Fixes #4538.

R=bradfitz
CC=golang-dev
https://golang.org/cl/12300043

The ResponseWriter's ReadFrom method was causing side effects on
the output before any data was read.

Now, bail out early and do a normal copy (which does a read
before writing) when our input and output are known to not to
be the pair of types we need for sendfile.

Fixes #5660

R=golang-dev, rsc, nightlyone
CC=golang-dev
https://golang.org/cl/12632043

I moved the pointer block from one end of the frame
to the other toward the end of working on the last CL,
and of course that made the optimization no longer work.

Now it works again:

0030 (bug361.go:12) DATA    gclocals·0+0(SB)/4,$4
0030 (bug361.go:12) DATA    gclocals·0+4(SB)/4,$3
0030 (bug361.go:12) GLOBL   gclocals·0+0(SB),8,$8

Fixes arm build (this time for sure!).

TBR=golang-dev
CC=cshapiro, golang-dev, iant
https://golang.org/cl/12627044

Sort non-pointer-containing data to the low end of the
stack frame, and make the bitmaps only cover the
pointer-containing top end.

Generates significantly less garbage collection bitmap
for programs with large byte buffers on the stack.

Only 2% shorter for godoc, but 99.99998% shorter
in some test cases.

Fixes arm build.

TBR=golang-dev
CC=cshapiro, golang-dev, iant
https://golang.org/cl/12541047

We weren't seeing additions. (stuff to put in next.txt)

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12678043

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12519046

R=gri
CC=golang-dev
https://golang.org/cl/12639043

The receiver name is optional. when Method's receiver name messing,
the functionList regex can't match the Method,
e.g. `func (*T) ProtoMessage() {}`.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12530044

Fixes #5900.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12669043

Individual variables bigger than 10 MB are now
moved to the heap, as if they had escaped on
their own.

This avoids ridiculous stacks for programs that
do things like
        x := [1<<30]byte{}
        ... use x ...

If 10 MB is too small, we can raise the limit.

Fixes #6077.

R=ken2
CC=golang-dev
https://golang.org/cl/12650045

Readdir's result should never contain a nil.

Fixes #5960.

R=golang-dev, rsc, bradfitz
CC=golang-dev
https://golang.org/cl/12261043

Fixes #5334.

R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/8653047

R=golang-dev
CC=golang-dev
https://golang.org/cl/12634044

Generated by addca.

R=gobot
CC=golang-dev
https://golang.org/cl/12671043

Fixes #4938.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12657044