This CL introduces new API into package net to identify the network
interface.  A functionality of new API is very similar to RFC3493 -
"Interface Identification".

R=r, gri, bradfitz, robert.hencke, fullung, rsc
CC=golang-dev
https://golang.org/cl/4437087

Input code like

0000 (x.go:2) TEXT    main+0(SB),$36-0
0001 (x.go:3) MOVL    $5,i+-8(SP)
0002 (x.go:3) MOVL    $0,i+-4(SP)
0003 (x.go:4) MOVL    $1,BX
0004 (x.go:4) MOVL    i+-8(SP),AX
0005 (x.go:4) MOVL    i+-4(SP),DX
0006 (x.go:4) MOVL    AX,autotmp_0000+-20(SP)
0007 (x.go:4) MOVL    DX,autotmp_0000+-16(SP)
0008 (x.go:4) MOVL    autotmp_0000+-20(SP),CX
0009 (x.go:4) CMPL    autotmp_0000+-16(SP),$0
0010 (x.go:4) JNE     ,13
0011 (x.go:4) CMPL    CX,$32
0012 (x.go:4) JCS     ,14
0013 (x.go:4) MOVL    $0,BX
0014 (x.go:4) SHLL    CX,BX
0015 (x.go:4) MOVL    BX,x+-12(SP)
0016 (x.go:5) MOVL    x+-12(SP),AX
0017 (x.go:5) CDQ     ,
0018 (x.go:5) MOVL    AX,autotmp_0001+-28(SP)
0019 (x.go:5) MOVL    DX,autotmp_0001+-24(SP)
0020 (x.go:5) MOVL    autotmp_0001+-28(SP),AX
0021 (x.go:5) MOVL    autotmp_0001+-24(SP),DX
0022 (x.go:5) MOVL    AX,(SP)
0023 (x.go:5) MOVL    DX,4(SP)
0024 (x.go:5) CALL    ,runtime.printint+0(SB)
0025 (x.go:5) CALL    ,runtime.printnl+0(SB)
0026 (x.go:6) RET     ,

is problematic because the liveness range for
autotmp_0000 (0006-0009) is nested completely
inside a span where BX holds a live value (0003-0015).
Because the register allocator only looks at 0006-0009
to see which registers are used, it misses the fact that
BX is unavailable and uses it anyway.

The n->pun = anyregalloc() check in tempname is
a workaround for this bug, but I hit it again because
I did the tempname call before allocating BX, even
though I then used the temporary after storing in BX.
This should fix the real bug, and then we can remove
the workaround in tempname.

The code creates pseudo-variables for each register
and includes that information in the liveness propagation.
Then the regu fields can be populated using that more
complete information.  With that approach, BX is marked
as in use on every line in the whole span 0003-0015,
so that the decision about autotmp_0000
(using only 0006-0009) still has all the information
it needs.

This is not specific to the 386, but it only happens in
generated code of the form

        load R1
        ...
        load var into R2
        ...
        store R2 back into var
        ...
        use R1

and for the most part the other compilers generate
the loads for a given compiled line before any of
the stores.  Even so, this may not be the case everywhere,
so the change is worth making in all three.

R=ken2, ken, ken
CC=golang-dev
https://golang.org/cl/4529106

Plus fix spoiling of GOMAXPROCS in 2 existing rwmutex tests.
Plus fix benchmark output to stdout (now it outputs to stderr like all other output).

R=rsc
CC=golang-dev
https://golang.org/cl/4529111

These changes are not particularly invasive and have been tested
as broadly as possible.

8l/l.h:
  -	#pragma varargck: added some, removed duplicates.

ld/dwarf.c:
  -	As Plan 9 has no NULL, changed all occurrences to nil.
  -	Added USED(size); where necessary.
  -	Added (void) argument in definition of finddebugruntimepath().
  -	Plan 9 compiler was complaining about multiple
        assignments, repeaired by breaking up the commands.
  -	Correction: havedynamic = 1; restored.

ld/go.c:
  -	Needed USED(file); in two functions.
  -	Removed unused assignments flagged by the Plan 9 compiler.

ld/lib.c:
  -	Replaced unlink() with remove() which seems available everywhere.
  -	Removed USED(c4); and USED(magic) no longer required.
  -	Removed code flagged as unused by the Plan 9 compiler.
  -	Added attributes to a number of format strings.

R=rsc
CC=golang-dev
https://golang.org/cl/4435047

also inlined a typechecking function in dcl away.

R=rsc
CC=golang-dev
https://golang.org/cl/4550115

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4547082

R=r
CC=golang-dev
https://golang.org/cl/4539104

This is in preparation of escape analysis; function parameters
can now be tagged with interesting bits by the compiler by
assigning to n->note.

tested by having typecheck put a fake tag on all parameters of
pointer type and compiling the tree.

R=rsc
CC=golang-dev
https://golang.org/cl/4524092

image: add Rectangle.ContainsRectangle method.

R=r, rsc
CC=golang-dev
https://golang.org/cl/4517130

R=r
CC=golang-dev
https://golang.org/cl/4551092

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4548091

R=golang-dev, dchest
CC=golang-dev
https://golang.org/cl/4564057

rune if input implements UnreadRune; otherwise the lookahead
will lie.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4548082

There were two issues:
1) It might not be a path error, it might be 'permission denied'.
2) The concept of $PATH is Unix-specific.

R=alex.brainman, rsc, r, mattn.jp
CC=golang-dev
https://golang.org/cl/4530096

Fixes #1905

R=rsc
CC=golang-dev
https://golang.org/cl/4538111

R=rsc
CC=golang-dev
https://golang.org/cl/4529110

R=rsc
CC=golang-dev
https://golang.org/cl/4559067

Fixes #1907.

R=rsc
CC=golang-dev
https://golang.org/cl/4527096

It gets annoying to do this in caller code otherwise,
especially having to remember to Close one side.

R=rsc
CC=golang-dev
https://golang.org/cl/4517134

The LDREXD and STREXD instructions require
aligned addresses, and the ARM stack is not
guaranteed to be aligned during the check.
This may cause other problems later (on the ARM
not all 64-bit pointers may be 64-bit aligned)
but at least the check is correct now.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/4564053

R=rsc
CC=golang-dev
https://golang.org/cl/4550111

R=rsc
CC=golang-dev
https://golang.org/cl/4528116

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/4517132

R=rsc
CC=golang-dev
https://golang.org/cl/4529100

Add IPv6Mreq and Inet6Pktinfo for specifying the network interface.
Rename IpMreq to IPMreq, SetsockoptIpMreq to SetsockoptIPMreq.

R=rsc, dave, robert.hencke
CC=golang-dev
https://golang.org/cl/4532098

Fixes #1792.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4548083

Programs expect that Read and Write are synchronous.
The background goroutines make the implementation
a little easier, but they introduce asynchrony that
trips up calling code.  Remove them.

R=golang-dev, krasin
CC=golang-dev
https://golang.org/cl/4548079

R=r
CC=golang-dev
https://golang.org/cl/4515179

Fixes #1883.
Fixes #1702.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4532103

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/4539100

Fixes #1840.

R=rsc
CC=golang-dev
https://golang.org/cl/4548077

R=bradfitz, rsc
CC=golang-dev
https://golang.org/cl/4524087

This changes the internal implementation of Cond so that
it uses two generations of waiters.  This enables Signal
to guarantee that it will only wake up waiters that are
currently sleeping at the call time.

Fixes #1648.

R=dvyukov, gustavo, rsc
CC=golang-dev
https://golang.org/cl/4524083

- tested with GOARCH=386
- tested with GOARCH=amd64

R=iant
CC=golang-dev
https://golang.org/cl/4526100

This removes exec.Run and replaces exec.Cmd with a
new implementation. The new exec.Cmd represents
both a currently-running command and also a command
being prepared. It has a good zero value.

You can Start + Wait on a Cmd, or simply Run it.
Start (and Run) deal with copying stdout, stdin,
and stderr between the Cmd's io.Readers and
io.Writers.

There are convenience methods to capture a command's
stdout and/or stderr.

R=r, n13m3y3r, rsc, gustavo, alex.brainman, dsymonds, r, adg, duzy.chan, mike.rosset, kevlar
CC=golang-dev
https://golang.org/cl/4552052

On a 32bit machine, the big.Words are only 32bit.

R=rsc
CC=golang-dev
https://golang.org/cl/4561055

R=rsc
CC=golang-dev
https://golang.org/cl/4559058

- better number scanning algorithm
- fixed a couple of bugs related to base interpretation
- added scan benchmark
- added more test cases and made tests more precise
- introduced Int.scan method matching nat.scan
- refactored Int.Scan; now uses int.scan
- refactored Int.SetString; now uses int.scan

There is more potential, this was a fairly simple change.

gotest -test.bench="ScanPi" before/after (best of 3 runs):
big.BenchmarkScanPi	   1000	    2024900 ns/op
big.BenchmarkScanPi       10000      257540 ns/op

R=chickencha
CC=golang-dev, rsc
https://golang.org/cl/4527089

Using the getaddrinfo order is only okay if we
are smart enough to try multiple addresses in Dial.
Since the code does not do that, we must make
the right first choice, regardless of what getaddrinfo
does, and more often that not that means using the
IPv4 address, even on IPv6 systems.  With the CL
applied, gotest fails in package net on OS X.

helix.cam=; gotest
...
--- FAIL: net.TestDialGoogleIPv4 (1.05 seconds)
        -- 74.125.226.179:80 --
        -- www.google.com:80 --
        Dial("tcp", "", "www.google.com:80") = _, dial tcp [2001:4860:800f::69]:80: address family not supported by protocol family
        -- 74.125.226.179:http --
        -- www.google.com:http --
        Dial("tcp", "", "www.google.com:http") = _, dial tcp [2001:4860:800f::69]:80: address family not supported by protocol family
        -- 074.125.226.179:0080 --
        -- [::ffff:74.125.226.179]:80 --
        -- [::ffff:4a7d:e2b3]:80 --
        -- [0:0:0:0:0000:ffff:74.125.226.179]:80 --
        -- [0:0:0:0:000000:ffff:74.125.226.179]:80 --
        -- [0:0:0:0:0:ffff::74.125.226.179]:80 --
FAIL
gotest: "./6.out" failed: exit status 1

««« original CL description
net: name-based destination address selection

getaddrinfo() orders the addresses according to RFC 3484.

This means when IPv6 is working on a host we get results like:
    []string = {"2001:4810::110", "66.117.47.214"}

and when it's not working we get:
    []string = {"66.117.47.214", "2001:4810::110"}

thus can drop firstFavoriteAddr.

This also means /etc/gai.conf works on relevant systems.

R=rsc, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/4557058

»»»

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/4532101

This mostly adds the infrastructure for writing various forms of
packets as well as reading them. Adding symmetric encryption support
was simply an easy motivation.

There's also one brown-paper-bag fix in here. Previously I had the
conditional for the MDC hash check backwards: the code was checking
that the hash was *incorrect*. This was neatly counteracted by another
bug: it was hashing the ciphertext of the OCFB prefix, not the
plaintext.

R=bradfitz
CC=golang-dev
https://golang.org/cl/4564046