The previous version was not handling an off_t (64 bit)
parameter on 32 bit i386 systems.  This patch splits sendfile
into two implementations in their respective arch-specific files.
Tested on FreeBSD amd64 and i386.

R=bradfitz
CC=golang-dev
https://golang.org/cl/6356048

1. Rename 'g' and 'm' local vars to 'gp' and 'mp' (convention already used in some functions)
'g' and 'm' are global vars that mean current goroutine and current machine,
when they are shadowed by local vars, it's confusing, no ability to debug log both, etc.
2. White-space shuffling.
No semantic changes.
In preparation to bigger changes.

R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/6355061

Fixes #2492

R=rsc, bradfitz
CC=golang-dev
https://golang.org/cl/6295073

There may be further savings if convT2I can avoid the function call
if the cache is good and T is uintptr-shaped, a la convT2E, but that
will be a follow-up CL.

src/pkg/runtime:
benchmark                  old ns/op    new ns/op    delta
BenchmarkConvT2ISmall             43           15  -64.01%
BenchmarkConvT2IUintptr           45           14  -67.48%
BenchmarkConvT2ILarge            130          101  -22.31%

test/bench/go1:
benchmark                 old ns/op    new ns/op    delta
BenchmarkBinaryTree17    8588997000   8499058000   -1.05%
BenchmarkFannkuch11      5300392000   5358093000   +1.09%
BenchmarkGobDecode         30295580     31040190   +2.46%
BenchmarkGobEncode         18102070     17675650   -2.36%
BenchmarkGzip             774191400    771591400   -0.34%
BenchmarkGunzip           245915100    247464100   +0.63%
BenchmarkJSONEncode       123577000    121423050   -1.74%
BenchmarkJSONDecode       451969800    596256200  +31.92%
BenchmarkMandelbrot200     10060050     10072880   +0.13%
BenchmarkParse             10989840     11037710   +0.44%
BenchmarkRevcomp         1782666000   1716864000   -3.69%
BenchmarkTemplate         798286600    723234400   -9.40%

R=rsc, bradfitz, go.peter.90, daniel.morsing, dave, uriel
CC=golang-dev
https://golang.org/cl/6337058

The switch at the beginning of the function already ensures n > 1,
so testing for n < 2 is redundant.

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/6350051

Occasionally I see:
--- FAIL: TestAllocations-15 (0.00 seconds)
        all_test.go:1575: 6 mallocs after 100 iterations
Tested:
$ go test -cpu=1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20 reflect

R=golang-dev, dsymonds, r
CC=golang-dev
https://golang.org/cl/6354063

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6348062

     Fixes #3789.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6357058

        Fixes #3765.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6349064

otherwise it fails spuriously with "newfunc allocated unexpectedly" message
when run with GOMAXPROCS>1 (other goroutine allocates).

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6347056

It will be required for scheduler that maintains
GOMAXPROCS MCache's.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6350062

No change, just for consistency.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6346048

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6356050

Some accumulated changes from the past few weeks.

Just cleans up all.bash output.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6354056

Generating env.bat using dist env -wp > env.bat failed silently
if case of an error, because the message was redirected to env.bat.
Verbose messages still go to stdout, causing problems, but that's
a seperate change.
Made errprintf() identical to xprintf(), except for the output handle.
Yes, it's duplicate code, but most of the function is unpacking
the argument list and preparing it for WriteFile(), which has to be
done anyway.

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/6343047

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6344049

        Fixes #3741.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6308076

The previous code assumed the gofmt output referred to /tmp but
that's not true if TMPDIR points somewhere else (like on Macs).
Fixes #3782.

R=sameer
CC=golang-dev
https://golang.org/cl/6346050

Fixes #3784

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6351052

R=bradfitz
CC=golang-dev
https://golang.org/cl/6357049

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6356046

- point out difference between selectors and qualified identifiers
- differentiate between illegal selectors and run-time panics
- use "indirect" as opposed to "dereference" consistently
- add extra links

Fixes #3779.

R=r, rsc, iant, ken
CC=golang-dev
https://golang.org/cl/6326059

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6350047

And update implementation location comment.

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/6352046

Updates #2362.

R=nigeltao
CC=golang-dev
https://golang.org/cl/6326057

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6354048

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6359043

TBR=bradfitz
CC=golang-dev
https://golang.org/cl/6358043

Alternative to https://golang.org/cl/6330044.

Fixes #3681.

R=golang-dev, r, hanwen, iant
CC=golang-dev
https://golang.org/cl/6335056

Current results on 2 core darwin/amd64:
BenchmarkGoroutineChain		351 ns/op
BenchmarkGoroutineChain-2	3840 ns/op
BenchmarkGoroutineChain-4	4040 ns/op
BenchmarkConcGoroutineChain	350 ns/op
BenchmarkConcGoroutineChain-2	875 ns/op
BenchmarkConcGoroutineChain-4	2027 ns/op

R=r, rsc
CC=golang-dev
https://golang.org/cl/6332054

Fixes #3763.

R=r, rsc, iant, ken
CC=golang-dev
https://golang.org/cl/6333066

I missed the API change in the last FreeBSD CL, but the tool caught it.

TBR=bradfitz
CC=golang-dev
https://golang.org/cl/6331063

Fixes #3630.

R=rsc
CC=bradfitz, dsymonds, golang-dev, rodrigo.moraes
https://golang.org/cl/6210067

R=golang-dev, rsc, bradfitz, devon.odell
CC=golang-dev
https://golang.org/cl/6221054

Guess I was wrong about being done for the day.

R=golang-dev, r
CC=golang-dev, unpantsu
https://golang.org/cl/6325060

Fixes #3752.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6331062

arm soft div and mod performance plays an important part
in runtime performance.

The currently implementation is very stable, but we believe
we can best it. This benchmark provides a reference point.

linux/arm omap4 pandaboard

BenchmarkUint32Div7     10000000               298 ns/op
BenchmarkUint32Div37    10000000               298 ns/op
BenchmarkUint32Div123   10000000               298 ns/op
BenchmarkUint32Div763   10000000               298 ns/op
BenchmarkUint32Div1247  10000000               299 ns/op
BenchmarkUint32Div9305  10000000               298 ns/op
BenchmarkUint32Div13307 10000000               298 ns/op
BenchmarkUint32Div52513 10000000               298 ns/op
BenchmarkUint32Div60978747      10000000               298 ns/op
BenchmarkUint32Div106956295     10000000               297 ns/op
BenchmarkUint32Mod7     10000000               280 ns/op
BenchmarkUint32Mod37    10000000               280 ns/op
BenchmarkUint32Mod123   10000000               280 ns/op
BenchmarkUint32Mod763   10000000               280 ns/op
BenchmarkUint32Mod1247  10000000               280 ns/op
BenchmarkUint32Mod9305  10000000               280 ns/op
BenchmarkUint32Mod13307 10000000               280 ns/op
BenchmarkUint32Mod52513 10000000               280 ns/op
BenchmarkUint32Mod60978747      10000000               280 ns/op
BenchmarkUint32Mod106956295     10000000               280 ns/op

R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6258067

It's just stutter.

R=golang-dev, dsymonds, r
CC=golang-dev
https://golang.org/cl/6334053

Number represents the actual JSON text,
preserving the precision and
formatting of the original input.

R=rsc, iant
CC=golang-dev
https://golang.org/cl/6202068

This is my last one for today, I hope!

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6339052