As much as 7x speedup on some programs, cuts all.bash time by 20%.

Change splicebefore function from O(n) to O(1).
The approach was suggested by Carl during the code's review
but apparently did not make it into the tree.
It makes a huge difference on huge programs.

Make twobitwalktype1 slightly faster by using & instead of %.
Really it needs to be cached; left a note to that effect.
(Not a complete fix, hence the ½.)

big.go (output of test/chan/select5.go)
 47.53u   0.50s  48.14r before this CL
  7.09u   0.47s   7.59r with splicebefore change (6.7x speedup)
  6.15u   0.42s   6.59r with twobitwalktype1 change (1.15x speedup; total 7.7x)

slow.go (variant of program in go.text, by mpvl)
 77.75u   2.11s  80.03r before this CL
 24.40u   1.97s  26.44r with splicebefore change (3.2x speedup)
 18.12u   2.19s  20.38r with twobitwalktype1 change (1.35x speedup; total 4.3x)

test/run
150.63u  49.57s  81.08r before this CL
 88.01u  45.60s  46.65r after this CL (1.7x speedup)

all.bash
369.70u 115.64s 256.21r before this CL
298.52u 110.35s 214.67r after this CL (1.24x speedup)

The test programs are at
https://rsc.googlecode.com/hg/testdata/big.go (36k lines, 276kB)
https://rsc.googlecode.com/hg/testdata/slow.go (7k lines, 352kB)

R=golang-codereviews, gobot, r
CC=cshapiro, golang-codereviews
https://golang.org/cl/43210045

Eventually we will want to bypass DATA for everything,
but the relocations are not standardized well enough across
architectures to make that possible.

This did not help as much as I expected, but it is definitely better.
It shaves maybe 1-2% off all.bash depending on how much you
trust the timings of a single run:

Before: 241.139r 362.702u 112.967s
After:  234.339r 359.623u 111.045s

R=golang-codereviews, gobot, r, iant
CC=golang-codereviews
https://golang.org/cl/44650043

Expand the type's doc comment to make its purpose clear
and discourage misuse.

R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/44680043

Generated by addca.

R=gobot
CC=golang-codereviews
https://golang.org/cl/44690043

R=adg, bradfitz
CC=golang-codereviews
https://golang.org/cl/44430043

And merge the blackhole.go file back into ioutil,
where it once was. It was only in a separate file
because it used to have race-vs-!race versions.

R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/44060044

These no longer work; removing them makes other refactoring easier.
The code for pack P being deleted in this CL does not work either.
I created issue 6989 to track restoring this functionality (probably not
until pack is written in Go).

R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/44300043

The practice of storing reference connections for testing has worked
reasonably well, but the large blocks of literal data in the .go files
is ugly and updating the tests is a real problem because their number
has grown.

This CL changes the way that reference tests work. It's now possible to
automatically update the tests and the test data is now stored in
testdata/. This should make it easier to implement changes that affect
all connections, like implementing the renegotiation extension.

R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/42060044

See this thread for background:
https://groups.google.com/forum/#!topic/golang-dev/xG7vPi21r8g

R=golang-codereviews, gobot, golang-dev, dsymonds
CC=golang-codereviews, golang-dev
https://golang.org/cl/44450043

Per RFC 4291, 'The use of "::" indicates one or more groups of 16 bits of zeros.'
Fixes #6628

R=golang-dev, rsc, minux.ma, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/15990043

R=golang-dev
CC=golang-dev
https://golang.org/cl/38030045

Fixes #6988.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/44070046

Needed for precise gc and copying stacks.

reflect.Value now takes 4 words instead of 3.

Still to do:
 - un-iword-ify channel ops.
 - un-iword-ify method receivers.

R=golang-dev, iant, rsc, khr
CC=golang-dev
https://golang.org/cl/43040043

This makes the linker's -X flag work again.

R=iant
CC=bradfitz, golang-codereviews, golang-dev
https://golang.org/cl/44360043

Notably, to show allocs. Currently: 11766 B/op, 21 allocs/op,
at least one alloc of which is in the benchmark loop itself.

R=golang-dev, jnewlin
CC=golang-dev
https://golang.org/cl/40370057

The runtime tests are executed 4 times in all.bash
and there is currently a 5-second delay each time.

R=golang-dev, minux.ma, khr, bradfitz
CC=golang-dev
https://golang.org/cl/42450043

R=golang-dev, lucio.dere, rsc
CC=golang-dev
https://golang.org/cl/44080046

The code is all about tags, and the cmd/go documentation
said to look in the go/build documentation for information
about tags, but the documentation said nothing about tags,
only build constraints. Make things clearer.

R=golang-dev, adg, rsc
CC=golang-dev
https://golang.org/cl/44100043

Since SHA-256 is now the default hash function, x509 should import it
otherwise some programs may fail because it hasn't been linked in.

R=golang-dev, dave, minux.ma
CC=golang-dev
https://golang.org/cl/44010047

1. expr append executable extension.
2. support '\r' character.

Fixes #6851.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/35330043

Make hostobj work on OpenBSD 5.3/5.4/-current - these have PIE
enabled by default and linking fails since the Go linker generates
objects that are neither PIC nor PIE.

Fixes #5067

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7572049

To make it possible to type "go test -run=DNS".
Also removes unnecessary parens.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/43470051

Fixes #6338

R=golang-dev, kin.wilson.za, rsc
CC=golang-dev
https://golang.org/cl/36180044

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/44180043

We did this elsewhere when io.ByteReader was added
but forgot this one.

R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/43480052

On the plus side, we don't need to change the bits when mallocing
pointerless objects.  On the other hand, we need to mark objects in the
free lists during GC.  But the free lists are small at GC time, so it
should be a net win.

benchmark                    old ns/op    new ns/op    delta
BenchmarkMalloc8                    40           33  -17.65%
BenchmarkMalloc16                   45           38  -15.72%
BenchmarkMallocTypeInfo8            58           59   +0.85%
BenchmarkMallocTypeInfo16           63           64   +1.10%

R=golang-dev, rsc, dvyukov
CC=cshapiro, golang-dev
https://golang.org/cl/41040043

Also removes an unused variable.

Fixes #6795.

R=adg, dave, bradfitz, gobot
CC=golang-dev
https://golang.org/cl/29440043

For machines, not threads.

Update #4720

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/44150043

Overloading size leads to problems if clients
try to set up an LSym by hand.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/44140043

R=r, bradfitz
CC=golang-dev
https://golang.org/cl/43480049

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/43480050

Update #4720

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/44080043

Benchmark is within the noise. I had to run this a dozen times
each before & after (on wall power, without a browser running)
before I could get halfway consistent numbers, and even then
they jumped all over the place, with the new one sometimes
being better. But these are the best of a dozen each.

Slowdown is expected anyway, since I imagine channels are
optimized more.

benchmark                 old ns/op    new ns/op    delta
BenchmarkCodeEncoder       26556987     27291072   +2.76%
BenchmarkEncoderEncode         1069         1071   +0.19%

benchmark                  old MB/s     new MB/s  speedup
BenchmarkCodeEncoder          73.07        71.10    0.97x

benchmark                old allocs   new allocs    delta
BenchmarkEncoderEncode            2            2    0.00%

benchmark                 old bytes    new bytes    delta
BenchmarkEncoderEncode          221          221    0.00%

Update #4720

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/37720047

Address several warnings generated by clang -fsanitize=undefined

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/43050043

Fixes #6576.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/14502065

Update #4078

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/14638043

sequences.

Use the same criteria for when to modify the tag type when
parsing a string in a sequence as when parsing a bare string
field.

Fixes #6726.

R=golang-dev, bradfitz, gobot, agl
CC=golang-dev
https://golang.org/cl/22460043

Float32 and Float64 are now both created by taking the ratio
of two integers which are chosen to fit entirely into the
precision of the desired float type. The previous code
could cast a Float64 with more than 23 bits of ".99999"
into a Float32 of 1.0, which is not in [0,1).

Float32 went from 15 to 21 ns/op (but is now correct).

Fixes #6721.

R=golang-dev, iant, rsc
CC=golang-dev
https://golang.org/cl/22730043

R=golang-dev, adg, rsc
CC=golang-dev
https://golang.org/cl/36950043

Fixes #6441.

R=r
CC=andybons, golang-dev
https://golang.org/cl/13829043