Followup to CL 19001.

Change-Id: I7fa838b1ee8df53229e9dd29a231c2f9b2aa3f69
Reviewed-on: https://go-review.googlesource.com/19003Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

It's causing the darwin-386 builder to fail with:

--- FAIL: TestDynlink (0.07s)
    obj6_test.go:118: error exit status 3 output go tool: no such tool "asm"
FAIL
FAIL    cmd/internal/obj/x86    0.073s

So skip it for now. It's tested in enough other places.

Change-Id: I9a98ad7b8be807005750112d892ac6c676c17dd5
Reviewed-on: https://go-review.googlesource.com/18989
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

This makes "CGO_ENABLED=0 go list runtime/cgo" work,
which fixes the current cmd/go test failure.

Change-Id: Ia55ce3ba1dbb09f618ae5f4c8547722670360f59
Reviewed-on: https://go-review.googlesource.com/19001
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

We set GOMAXPROCS=1 to prevent test flakiness.
There are two sources of flakiness:
1. Some tests rely on particular execution order.
   If the order is different, race does not happen at all.
2. Ironically, ThreadSanitizer runtime contains a logical race condition
   that can lead to false negatives if racy accesses happen literally at the same time.
Tests used to work reliably in the good old days of GOMAXPROCS=1.
So let's set it for now. A more reliable solution is to explicitly annotate tests
with required execution order by means of a special "invisible" synchronization primitive
(that's what is done for C++ ThreadSanitizer tests). This is issue #14119.

This reduces flakes on RaceAsFunc3 test from 60/3000 to 1/3000.

Fixes #14086
Fixes #14079
Fixes #14035

Change-Id: Ibaec6b2b21e27b62563bffbb28473a854722cf41
Reviewed-on: https://go-review.googlesource.com/18968Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

CL 18964 included an extra patch (sorry, my first experience of
git-codereview) which defined the conventional breakpoint instruction
used by Plan 9 on arm, but also introduced a benign but unneeded
call to runtime.emptyfunc.  This CL removes the redundant call again.

This completes the series of CLs which add support for Plan 9 on arm.

Change-Id: Id293cfd40557c9d79b4b6cb164ed7ed49295b178
Reviewed-on: https://go-review.googlesource.com/19010Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Also fix a few bad links.

Change-Id: If04cdd312db24a827a3c958a9974c50ab148656c
Reviewed-on: https://go-review.googlesource.com/18979Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The vendored copy of golang.org/x/net/http/hpack was being treated
as not standard, which in turn was making it not subject to the mtime
exception for rebuilding the standard library in a release, which in turn
was making net/http look out of date.

One fix and three tests:

- Fix the definition of standard.
- Test that everything in $GOROOT/src/ is standard during 'go test cmd/go'.
(In general there can be non-standard things in $GOROOT/src/, but this
test implies that you can do that or you can run 'go test cmd/go',
but not both. That's fine.)
- Test that 'go list std cmd' shows our vendored code.
- Enforce that no standard package can depend on a non-standard one.

Also fix a few error printing nits.

Fixes #13713.

Change-Id: I1f943f1c354174c199e9b52075c11ee44198e81b
Reviewed-on: https://go-review.googlesource.com/18978Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>

Change-Id: I595379d2f02b0a43735f0375758e4997ce3b64a7
Reviewed-on: https://go-review.googlesource.com/18986
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ibba7fccba9617612e026bd0a208eb12918de465a
Reviewed-on: https://go-review.googlesource.com/18985Reviewed-by: Russ Cox <rsc@golang.org>

Martin Lenord pointed out that bad patterns have emerged in online
examples of how to use ServeFile, where people pass r.URL.Path[1:] to
ServeFile. This is unsafe. Document that it's unsafe, and add some
protections.

Fixes #14110

Change-Id: Ifeaa15534b2b3e46d3a8137be66748afa8fcd634
Reviewed-on: https://go-review.googlesource.com/18939Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Add magic word for Plan 9 ARM object header to objectMagic table.

Change-Id: I21eb8845a2ee2e8cdddc0849eedf43481aee9cde
Reviewed-on: https://go-review.googlesource.com/18963Reviewed-by: Russ Cox <rsc@golang.org>

Fields in Plan 9 object headers are big-endian, on all architectures.

Change-Id: If95ad29750b776338178d660646568bf26a4abda
Reviewed-on: https://go-review.googlesource.com/18964Reviewed-by: Russ Cox <rsc@golang.org>

Also document the special behavior of Alignof(s.f), and mention the
correspondence between Alignof and reflect.Type.{Align,FieldAlign}.

Change-Id: I6f81047a04c86887f1b1164473225616cae45a26
Reviewed-on: https://go-review.googlesource.com/18949
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Fixes #9157

Change-Id: Iadf305a172a0ec53ae91e1b2db3f3351691a48ff
Reviewed-on: https://go-review.googlesource.com/18935Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

It's possible for arena_start+MaxArena32 to wrap.
We do the right thing in the bounds check but not in the print.

For #13992 (to fix the print there, not the bug).

Change-Id: I4df845d0c03f0f35461b128e4f6765d3ccb71c6d
Reviewed-on: https://go-review.googlesource.com/18975
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

The previous CL is the real fix. This one is just insurance.

Fixes #14046 again.

Change-Id: I553349504bb1789e4b66c888dbe4034568918ad6
Reviewed-on: https://go-review.googlesource.com/18977Reviewed-by: Austin Clements <austin@google.com>

It was just completely broken if you gave it the number
of records it asked for. Make it impossible for that particular
inconsistency to happen again.

Also make it exclude system goroutines, to match both
NumGoroutine and Stack.

Fixes #14046.

Change-Id: Ic238c6b89934ba7b47cccd3440dd347ed11e4c3d
Reviewed-on: https://go-review.googlesource.com/18976
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

For Go 1.7 we can remove all the code.google.com code
(except maybe the shutdown warning).

See #10193.

Change-Id: I4b8182eb66494f0bf373b40ca5da6ae4738342be
Reviewed-on: https://go-review.googlesource.com/18974Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This has been flaking on the new OpenBSD 5.8 builders lately:
https://storage.googleapis.com/go-build-log/808270e7/openbsd-amd64-gce58_61ce2663.log
(as one example)

Add more debug info when it fails.

Updates #14107

Change-Id: Ie30bc0c703d2e9ee993d1e232ffc5f2d17e65c97
Reviewed-on: https://go-review.googlesource.com/18938
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Currently p.gcBgMarkWorker is a *g. Change it to a guintptr. This
eliminates a write barrier during the subtle mark worker parking dance
(which isn't known to be causing problems, but may).

Change-Id: Ibf12c05ac910820448059e69a68e5b882c993ed8
Reviewed-on: https://go-review.googlesource.com/18970
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

traceEvent records system call events after a G has already entered
_Gsyscall, which means the garbage collector could be installing stack
barriers in the G's stack during the traceEvent. If traceEvent
attempts to capture the user stack during this, it may observe a
inconsistent stack barriers and panic. Fix this by acquiring the stack
lock around the stack walk in traceEvent.

Fixes #14101.

Change-Id: I15f0ab0c70c04c6e182221f65a6f761c5a896459
Reviewed-on: https://go-review.googlesource.com/18973
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Currently mark workers attach to their designated Ps before parking,
either during initialization or after performing a phase transition.
However, in both of these cases, it's possible that the mark worker is
running on a different P than the one it attaches to. This is a
problem, because as soon as the worker attaches to a P, that P's
scheduler can execute the worker. If the worker hasn't yet parked on
the P it's actually running on, this means the worker G will be
running in two places at once. The most visible consequence of this is
that once the first instance of the worker does park, it will clear
g.m and the second instance will crash shortly when it tries to use
g.m.

Fix this by moving the attach to the gopark callback. At this point,
the G is genuinely stopped and the callback is running on the system
stack, so it's safe for another P's scheduler to pick up the worker G.

Fixes #13363. Fixes #13978.

Change-Id: If2f7c4a4174f9511f6227e14a27c56fb842d1cc8
Reviewed-on: https://go-review.googlesource.com/18761Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>

The current code delays the literal pool until the very last moment,
but based on the assumption that span-dependent jumps are as
short as possible. If they need to be enlarged in a later round, that
very last moment may be too late. Flush a little early to prevent that.

Fixes #13579.

Change-Id: I759b5db5c43a977bf2b940872870cbbc436ad141
Reviewed-on: https://go-review.googlesource.com/18972Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Russ Cox <rsc@golang.org>

Clarify that Compressor and Decompressor callbacks must support being invoked
concurrently, but that the writer or reader returned need not be.

Updates #8359

Change-Id: Ia407b581dd124185f165c25f5701018a8ce4357a
Reviewed-on: https://go-review.googlesource.com/18627Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

This debugging print crept into an earlier CL of mine.

Change-Id: If6e8609e69a60aec50c06889c2d98a8b8a4bd02b
Reviewed-on: https://go-review.googlesource.com/18971
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

In some cases the documentation for functions in this package was
lacking from the beginning and, in order cases, the documentation didn't
keep pace as the package grew.

This change somewhat addresses that.

Updates #13711.

Change-Id: I25b2bb1fcd4658c5417671e23cf8e644d08cb9ab
Reviewed-on: https://go-review.googlesource.com/18486Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #13954

Change-Id: I4c01e9bb3fb08e8b9fa14d4c59b7ea824ba3f0c9
Reviewed-on: https://go-review.googlesource.com/18937Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Currently we run profiling tests for around 200ms in short mode.
However, even on platforms with good profiling, these tests are
inherently flaky, especially on loaded systems like the builders.

To mitigate this, modify the profiling test harness so that if a test
fails in a way that could indicate there just weren't enough samples,
it retries with a longer duration.

This requires some adjustment to the profile checker to distinguish
"fatal" and "retryable" errors. In particular, we no longer consider
it a fatal error to get a profile with zero samples (which we
previously treated as a parse error). We replace this with a retryable
check that the total number of samples is reasonable.

Fixes #13943. Fixes #13871. Fixes #13223.

Change-Id: I9a08664a7e1734c5334b1f3792a56184fe314c4d
Reviewed-on: https://go-review.googlesource.com/18683Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates x/net/http2 to git rev eb066e3 for https://golang.org/cl/18932

Fixes #13925
Fixes #14061

Change-Id: I73f8c09232877404362358240b7b369bb9c76a12
Reviewed-on: https://go-review.googlesource.com/18934Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #14103

Change-Id: I89963643eccc902b809e04b7a14153acb0d242e1
Reviewed-on: https://go-review.googlesource.com/18933Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #14020

Change-Id: I454c2613912a7efcb464c6e6f3ac2e0ec89fb719
Reviewed-on: https://go-review.googlesource.com/18750Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Chris Broadfoot <cbro@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

People who want to use -buildmode=c-archive in unusual cross-compilation
setups will need something like this.  It could also be done via (yet
another) environment variable but I use -extar by analogy with the
existing -extld.

Change-Id: I354cfabc4c470603affd13cd946997b3a24c0e6c
Reviewed-on: https://go-review.googlesource.com/18913Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I8c647e709d93a76636e04375609fceadf3754aa1
Reviewed-on: https://go-review.googlesource.com/18954Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #13938.

Change-Id: I0b4842b8bc22dc79323d6894c123cde638f52d3f
Reviewed-on: https://go-review.googlesource.com/18856Reviewed-by: Adam Langley <agl@golang.org>

Windows: putting spaces where they don't belong since Windows NT 3.1.

Fixes #14002.

Change-Id: I48ba8a7bfe3f27f83c8aa8355a8d355933d6c5df
Reviewed-on: https://go-review.googlesource.com/18855Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Add example of how to use the aes package to
implement AES encryption and decryption
within an application.

Per feedback, use more secure AES-GCM implementation as an
example in crypto/cipher instead of AES directly.

Change-Id: I84453ebb18e0bc79344a24171a031ec0d7ccec2e
Reviewed-on: https://go-review.googlesource.com/18803Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #14099.

Change-Id: I122e918bdc55fb185f4a4a797489b160219542d2
Reviewed-on: https://go-review.googlesource.com/18943
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Was part of #13822 but not in the first message, so I missed it.

Fixes #13822 again.

Change-Id: I775004fa8d47b6af293124605521ec396573e267
Reviewed-on: https://go-review.googlesource.com/18900
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I85fa5e672a476098f8711dcbb5b20ea1a3fa630d
Reviewed-on: https://go-review.googlesource.com/18953Reviewed-by: Ian Lance Taylor <iant@golang.org>

Use of the alternate signal stack on darwin/{arm,arm64} is reportedly
buggy, and the runtime function sigaltstack does nothing.  So don't
check the sigaltstack result to decide how to handle the signal stack.

Fixes #14070.

Change-Id: Ie97ede8895fad721e3acc79225f2cafcbe1f3a81
Reviewed-on: https://go-review.googlesource.com/18940
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>