Updates #16360.

Adds examples for:
+ CombinedOutput
+ StdinPipe
+ StderrPipe

Change-Id: I19293e64b34ed9268da00e0519173a73bfbc2c10
Reviewed-on: https://go-review.googlesource.com/29150
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

Since the legacy backends were removed, these fields are write-only.

Change-Id: I4816c39267b7c10a4da2a6d22cd367dc475e564d
Reviewed-on: https://go-review.googlesource.com/29246
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Dave Cheney <dave@cheney.net>

Follow up to CL 29134. Generated with gofmt -r 'Nod -> nod', plus
three manual adjustments to the comments in syntax/parser.go

Change-Id: I02920f7ab10c70b6e850457b42d5fe35f1f3821a
Reviewed-on: https://go-review.googlesource.com/29136Reviewed-by: Matthew Dempsky <mdempsky@google.com>

According to golang.org/s/go12symtab, for N files, it should put N+1
there.

Fixes #17132.

Change-Id: I0c84136855c6436be72b9d3c407bf10d4c81a099
Reviewed-on: https://go-review.googlesource.com/29275
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Change-Id: I5c2fd0ff1b49f3826f2b9869b0b11329804b0e2a
Reviewed-on: https://go-review.googlesource.com/29244
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

Only added lines are moving amd64 and x86's ginsnop functions from
gsubr.go to ggen.go to match other architectures, so all of the
gsubr.go files can go away.

Change-Id: Ib2292460c155ae6d9dcf5c9801f178031d8eea7a
Reviewed-on: https://go-review.googlesource.com/29240
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

Change-Id: I0131b0d7421ff1397f16a08eff758250abbdf8e2
Reviewed-on: https://go-review.googlesource.com/29239Reviewed-by: Dave Cheney <dave@cheney.net>

Effective Go has references to a function call f(c, req) made by ServeHTTP mixed with f(w,
req). c is dropped in favor of w to maintain consistency

Fixes #17128

Change-Id: I6746fd115ed5a58971fd24e54024d29d18ead1fa
Reviewed-on: https://go-review.googlesource.com/29311Reviewed-by: Rob Pike <r@golang.org>

ReadMsgUnix and WriteMsgUnix both will read/write 1 byte from/to the
socket if they were given no buffer to read/write, to avoid a common
pitfall in out of band operations (they will usually block
indefinitely if there's no actual data to read).

This patch adds a note about this behaviour in their documentation, so
users can be aware of it.

Change-Id: I751f0e12bb4d80311e94ea8de023595c5d40ec3e
Reviewed-on: https://go-review.googlesource.com/29180
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Binary search remains our friend.
Suppose you add an ought-to-be-benign pattern to PPC64.rules,
and make.bash starts crashing.  You can guard the pattern(s)
with config.DebugTest:

(Eq8 x y) && config.DebugTest && isSigned(x.Type) &&
   isSigned(y.Type) ->
   (Equal (CMPW (SignExt8to32 x) (SignExt8to32 y)))

and then

  gossahash -s ./make.bash
  ...
  (go drink beer while silicon minions toil)
  ...
  Trying ./make.bash args=[], env=[GOSSAHASH=100110010111110]
  ./make.bash failed (1 distinct triggers): exit status 1
  Trigger string is 'GOSSAHASH triggered (*importReader).readByte',
    repeated 1 times
  Review GSHS_LAST_FAIL.0.log for failing run
  Finished with GOSSAHASH=100110010111110

Change-Id: I4eff46ebaf496baa2acedd32e217005cb3ac1c62
Reviewed-on: https://go-review.googlesource.com/29273
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Everything is SSA now.

Update #16357

Change-Id: I436dbe367b863ee81a3695a7d653ba4bfc5b0f6c
Reviewed-on: https://go-review.googlesource.com/29232Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Delete legacy backend tests, make SSA tests unconditional.

Next CL will remove _ssa from the file names.

Update #16357

Change-Id: I2a7f5dcbc69455f63b5e6e6b2725df26ab86c8dd
Reviewed-on: https://go-review.googlesource.com/29231
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #17040

Change-Id: I3682cc0367b919084c280d7dc64746495c1d4aaa
Reviewed-on: https://go-review.googlesource.com/28872Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Also remove the hard-coded path for getting glibc information.

As an example, the following is the diff for `go bug` on Ubuntu before
and after the change:

>>>
--- /tmp/01     2016-09-13 15:08:53.202758043 +0530
+++ /tmp/02     2016-09-13 21:38:17.485039867 +0530
@@ -1,7 +1,7 @@
 Please check whether the issue also reproduces on the latest release, go1.7.1.

 ```
-go version devel +bdb3b790 Wed Sep 7 03:23:44 2016 +0000 linux/amd64
+go version devel +cb13150 Wed Sep 7 09:46:58 2016 +0530 linux/amd64
 GOARCH="amd64"
 GOBIN=""
 GOEXE=""
@@ -18,5 +18,23 @@
 CXX="g++"
 CGO_ENABLED="1"
 uname -sr: Linux 4.4.0-36-generic
+Distributor ID:        Ubuntu
+Description:   Ubuntu 16.04.1 LTS
+Release:       16.04
+Codename:      xenial
+/lib/x86_64-linux-gnu/libc.so.6: GNU C Library (Ubuntu GLIBC 2.23-0ubuntu3) stable release version 2.23, by Roland McGrath et al.
 gdb --version: GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
 ```
<<<

Change-Id: I7e3730a797af0f94d6e43fe4743ab48bc0f11f1b
Reviewed-on: https://go-review.googlesource.com/28581
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

GOSSAFUNC=foo had previously only done printing for the
single function foo, and didn't quite clean up after itself
properly. Changes ensures that Config.HTML != nil iff
GOSSAFUNC==name-of-current-function.

Change-Id: I255e2902dfc64f715d93225f0d29d9525c06f764
Reviewed-on: https://go-review.googlesource.com/29250
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The only remaining consumers of gins were
ginsnop and arch-independent opcodes like GVARDEF.
Rewrite ginsnop to create and populate progs directly.
Move arch-independent opcodes to package gc
and simplify.
Delete some now unused code.
There is more.
Step one towards eliminating gc.Node.Reg.

Change-Id: I7c34cd8a848f6fc3b030705ab8e293838e0b6c20
Reviewed-on: https://go-review.googlesource.com/29220
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes the build.

Change-Id: Ib9aca6cf86d595d20f22dbf730afa8dea4b44672
Reviewed-on: https://go-review.googlesource.com/29221Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Unroll s == "ab" to

len(s) == 2 && s[0] == 'a' && s[1] == 'b'

This generates faster and shorter code
by avoiding a runtime call.
Do something similar for !=.

The cutoff length is 6. This was chosen empirically
by examining binary sizes on arm, arm64, 386, and amd64
using the SSA backend.

For all architectures examined, 4, 5, and 6 were
the ideal cutoff, with identical binary sizes.

The distribution of constant string equality sizes
during 'go build -a std' is:

 40.81%   622 len 0
 14.11%   215 len 4
  9.45%   144 len 1
  7.81%   119 len 3
  7.48%   114 len 5
  5.12%    78 len 7
  4.13%    63 len 2
  3.54%    54 len 8
  2.69%    41 len 6
  1.18%    18 len 10
  0.85%    13 len 9
  0.66%    10 len 14
  0.59%     9 len 17
  0.46%     7 len 11
  0.26%     4 len 12
  0.20%     3 len 19
  0.13%     2 len 13
  0.13%     2 len 15
  0.13%     2 len 16
  0.07%     1 len 20
  0.07%     1 len 23
  0.07%     1 len 33
  0.07%     1 len 36

A cutoff of length 6 covers most of the cases.

Benchmarks on amd64 comparing a string to a constant of length 3:

Cmp/1same-8           4.78ns ± 6%  0.94ns ± 9%  -80.26%  (p=0.000 n=20+20)
Cmp/1diffbytes-8      6.43ns ± 6%  0.96ns ±11%  -85.13%  (p=0.000 n=20+20)
Cmp/3same-8           4.71ns ± 5%  1.28ns ± 5%  -72.90%  (p=0.000 n=20+20)
Cmp/3difffirstbyte-8  6.33ns ± 7%  1.27ns ± 7%  -79.90%  (p=0.000 n=20+20)
Cmp/3difflastbyte-8   6.34ns ± 8%  1.26ns ± 9%  -80.13%  (p=0.000 n=20+20)

The change to the prove test preserves the
existing intent of the test. When the string was
short, there was a new "proved in bounds" report
that referred to individual byte comparisons.

Change-Id: I593ac303b0d11f275672090c5c786ea0c6b8da13
Reviewed-on: https://go-review.googlesource.com/26758
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I14a7c08105e6bdcee04a5cc21d7932e9ca753384
Reviewed-on: https://go-review.googlesource.com/29138
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fix conflict between CL 29213 and 29134.

Change-Id: Ie58bd7195893d7e634f1b257ee0bdd3250cd23c2
Reviewed-on: https://go-review.googlesource.com/29137
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

staticassign unwraps all CONVNOPs.
However, in the included test, we need the
CONVNOP for everything to typecheck.
Stop unwrapping unnecessarily.

The code we generate for this example is
suboptimal, but that's not new; see #17113.

Fixes #17111.

Change-Id: I29532787a074a6fe19a5cc53271eb9c84bf1b576
Reviewed-on: https://go-review.googlesource.com/29213
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

After the removal of the old backend many types are no longer referenced
outside internal/gc. Make these functions private so that tools like
honnef.co/go/unused can spot when they become dead code. In doing so
this CL identified several previously public helpers which are no longer
used, so removes them.

This should be the last of the public functions.

Change-Id: I7e9c4e72f86f391b428b9dddb6f0d516529706c3
Reviewed-on: https://go-review.googlesource.com/29134
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Instead of dumping information for the use
to copy/paste into the issue tracker,
open the issue tracker directly with a pre-filled
template.

Change-Id: I370d0063b609200497014ccda35244fa4314a662
Reviewed-on: https://go-review.googlesource.com/29210
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: If8d27cf1cd8d650ed0ba332448d3174d80b6b0ca
Reviewed-on: https://go-review.googlesource.com/29217
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ifa7a882b020f7b0c9602c28c3e5567e5d4c39e73
Reviewed-on: https://go-review.googlesource.com/29216
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>

Consistently use int16 for [ft]reg and int64 for [ft]offset.

Change-Id: I7d279bb6e4fb735105429234a949074bf1cefb29
Reviewed-on: https://go-review.googlesource.com/29215
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>

Change-Id: Ib05a8e149db8accdb1474703cd7b7004243d91d4
Reviewed-on: https://go-review.googlesource.com/29214
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

These are no longer reachable as gins dispatches to ginscon for all
arch-specific instructions anyway.

Change-Id: I7f34883c16058308d8afa0f960dcf554af31bfe4
Reviewed-on: https://go-review.googlesource.com/29211Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

After the removal of the old backend many types are no longer referenced
outside internal/gc. Make these functions private so that tools like
honnef.co/go/unused can spot when they become dead code. In doing so
this CL identified several previously public helpers which are no longer
used, so removes them.

Change-Id: Idc2d485f493206de9d661bd3cb0ecb4684177b32
Reviewed-on: https://go-review.googlesource.com/29133
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Remove unused functions spotted by honnef.co/go/unused.

Change-Id: Iabf3b201215ce21e420a60f4ef2679b36231eda7
Reviewed-on: https://go-review.googlesource.com/29132
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

It's not everything, but it is a good start.

I tried to make the CL delete only.  goimports forced
a few exceptions to that rule.

Update #16357

Change-Id: I041925cb2fe68bb7ae1617af862b22c48da649c1
Reviewed-on: https://go-review.googlesource.com/29168
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Martin Möhrmann <martisch@uos.de>

Get rid of BlockCheck. Josh goaded me into it, and I went
down a rabbithole making it happen.

NilCheck now panics if the pointer is nil and returns void, as before.
BlockCheck is gone, and NilCheck is no longer a Control value for
any block. It just exists (and deadcode knows not to throw it away).

I rewrote the nilcheckelim pass to handle this case.  In particular,
there can now be multiple NilCheck ops per block.

I moved all of the arch-dependent nil check elimination done as
part of ssaGenValue into its own proper pass, so we don't have to
duplicate that code for every architecture.

Making the arch-dependent nil check its own pass means I needed
to add a bunch of flags to the opcode table so I could write
the code without arch-dependent ops everywhere.

Change-Id: I419f891ac9b0de313033ff09115c374163416a9f
Reviewed-on: https://go-review.googlesource.com/29120
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

We will soon add dedicated builders for running vet/all.
Their name will end with "-vetall".
On those builders, run vet/all and nothing else.
On all other builders, including local all.bash,
don't run vet/all at all, because it is slow.

This will probably be refined more over time.

Change-Id: Ib1d0337adda84353931a325515c132068d4320cd
Reviewed-on: https://go-review.googlesource.com/28962
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Passes toolstash -cmp.

Fixes #16870.

Change-Id: I70dc3bbb3cd3031826e5a54b96ba1ea603c282d1
Reviewed-on: https://go-review.googlesource.com/27910
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

when not instrumenting:
- Intrinsify uses of slicebytetostringtmp within the runtime package
  in the ssa backend.
- Pass OARRAYBYTESTRTMP nodes to the compiler backends for lowering
  instead of generating calls to slicebytetostringtmp.

name                    old time/op  new time/op  delta
ConcatStringAndBytes-4  27.9ns ± 2%  24.7ns ± 2%  -11.52%  (p=0.000 n=43+43)

Fixes #17044

Change-Id: I51ce9c3b93284ce526edd0234f094e98580faf2d
Reviewed-on: https://go-review.googlesource.com/29017
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: I63e7fd7f62aa80e1252b0c5b6c472439aa66da73
Reviewed-on: https://go-review.googlesource.com/29169Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

It is unlikely that the value of UnixNano overflow in most
use cases. However, the max date of 2262 is also within the range
where it may be of concern to some users. Rather than have each
person recompute when this overflows to validate if its okay for
their use case, we just document it as within the years 1678 and
2262, for user's convenience.

Fixes #16977

Change-Id: I4988738c147f4a6d30f8b8735c3941b75113bb16
Reviewed-on: https://go-review.googlesource.com/28478Reviewed-by: Andrew Gerrand <adg@golang.org>

Prepared with gofmt -r.

Change-Id: Ib9f224cc20353acd9c5850dead1a2d32ca5427d3
Reviewed-on: https://go-review.googlesource.com/29165
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

No need to test so many sizes in race mode, especially for a package
which doesn't use goroutines.

Reduces test time from 2.5 minutes to 25 seconds.

Updates #17104

Change-Id: I7065b39273f82edece385c0d67b3f2d83d4934b8
Reviewed-on: https://go-review.googlesource.com/29163Reviewed-by: David Crawshaw <crawshaw@golang.org>

No coverage is gained by running the 1e6 versions of the test over the
1e4 versions. It just adds 140 seconds of race overhead time.

Updates #17104

Change-Id: I41408aedae34a8b1a148eebdda20269cdefffba3
Reviewed-on: https://go-review.googlesource.com/29159
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>