A paranoid go at constant time implementation of P256 curve.

This code relies on z13 SIMD instruction set. For zEC12 and below,
the fallback is the existing P256 implementation. To facilitate this
fallback mode, I've refactored the code so that implementations can
be picked at run-time.

Its 'slightly' difficult to grok, but there is ASCII art..

name            old time/op  new time/op  delta
BaseMultP256     419µs ± 3%    27µs ± 1%  -93.65% (p=0.000 n=10+8)
ScalarMultP256  1.05ms ±10%  0.09ms ± 1%  -90.94% (p=0.000 n=10+8)

Change-Id: Ic1ded898a2ceab055b1c69570c03179c4b85b177
Reviewed-on: https://go-review.googlesource.com/31231
Run-TryBot: Michael Munday <munday@ca.ibm.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
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Implements subset of MIPS32(r1) instruction set.

Change-Id: Iba017350f6c2763de05d4d1bc2f123e8eb76d0ff
Reviewed-on: https://go-review.googlesource.com/31475
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Fixes #17606

Change-Id: I040c7621cef265d44b58f16556e6d58660a2245d
Reviewed-on: https://go-review.googlesource.com/32889
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>

Add tmpdir as a parameter to the closure otherwise the subsequent
modifications to tmpdir causes only the last subdirectory to be
removed.

Additionally, add the missing argument for the t.Fatalf call.

Change-Id: I3df53f9051f7ea40cf3f846d47d9cefe445e9b9d
Reviewed-on: https://go-review.googlesource.com/32892Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #11944.

Change-Id: I424ba93725f22fd599e052eb182f9ba2fca8e8bd
Reviewed-on: https://go-review.googlesource.com/32881Reviewed-by: Alan Donovan <adonovan@google.com>

Updates #17824.

Change-Id: I73cf89c21b418158c7014c3271cd1103a17a5c86
Reviewed-on: https://go-review.googlesource.com/32882Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Id3d571666b9275e3fa5cb20762afbd391dbcdeba
Reviewed-on: https://go-review.googlesource.com/32883Reviewed-by: Minux Ma <minux@golang.org>

// Executable returns the path name for the executable that started
// the current process. There is no guarantee that the path is still
// pointing to the correct executable. If a symlink was used to start
// the process, depending on the operating system, the result might
// be the symlink or the path it pointed to. If a stable result is
// needed, path/filepath.EvalSymlinks might help.
//
// Executable returns an absolute path unless an error occurred.
//
// The main use case is finding resources located relative to an
// executable.
//
// Executable is not supported on nacl or OpenBSD (unless procfs is
// mounted.)
func Executable() (string, error) {
	return executable()
}

Fixes #12773.

Change-Id: I469738d905b12f0b633ea4d88954f8859227a88c
Reviewed-on: https://go-review.googlesource.com/16551
Run-TryBot: Minux Ma <minux@golang.org>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

For os.Executable. Updates #12773.

Change-Id: Iff6593514b7453b6c5e1f20079e35cb4992cc74a
Reviewed-on: https://go-review.googlesource.com/32877Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ice8f3b42194852f7ee8f00f004e80014d1ea119b
Reviewed-on: https://go-review.googlesource.com/32875Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This commit also adds a test for pkg-config usage in cgo.

Fixes #16455.

Change-Id: I95fb6a288a4d19093c4613c93878017d95cbe4a2
Reviewed-on: https://go-review.googlesource.com/32735
Run-TryBot: Quentin Smith <quentin@golang.org>
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Reviewed-by: Russ Cox <rsc@golang.org>

CL 32871 updated the default cipher suites to use AES-GCM in
preference to ChaCha20-Poly1305 on platforms which have hardware
implementations of AES-GCM. This change makes BenchmarkThroughput
use the default cipher suites instead of the test cipher suites to
ensure that the recommended (fastest) algorithms are used.

Updates #17779.

Change-Id: Ib551223e4a00b5ea197d4d73748e1fdd8a47c32d
Reviewed-on: https://go-review.googlesource.com/32838
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>

For #17812.

Change-Id: I58411aaa0e8b2250a16ddb20c951e39da3d601e8
Reviewed-on: https://go-review.googlesource.com/32872Reviewed-by: Alan Donovan <adonovan@google.com>

Windows has a limit of 260 characters on normal paths, but it's possible
to use longer paths by using "extended-length paths" that begin with
`\\?\`. This commit attempts to transparently convert an absolute path
to an extended-length path, following the subtly different rules those
paths require. It does not attempt to handle relative paths, which
continue to be passed to the operating system unmodified.

This adds a new test, TestLongPath, to the os package. This test makes
sure that it is possible to write a path at least 400 characters long
and runs on every platform. It also tests symlinks and hardlinks, though
symlinks are not testable with our builder configuration.

HasLink is moved to internal/testenv so it can be used by multiple tests.

https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
has Microsoft's documentation on extended-length paths.

Fixes #3358.
Fixes #10577.
Fixes #17500.

Change-Id: I4ff6bb2ef9c9a4468d383d98379f65cf9c448218
Reviewed-on: https://go-review.googlesource.com/32451
Run-TryBot: Quentin Smith <quentin@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Change-Id: Ie21df37016c90cd0479c23ec4845f8195dd90fda
Reviewed-on: https://go-review.googlesource.com/16518Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Icd77ccbfe6a31117a11effb949b5826950df75a9
Reviewed-on: https://go-review.googlesource.com/16550Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Support for ChaCha20-Poly1305 ciphers was recently added to crypto/tls.
These ciphers are preferable in software, but they cannot beat hardware
support for AES-GCM, if present.

This change moves detection for hardware AES-GCM support into
cipher/internal/cipherhw so that it can be used from crypto/tls. Then,
when AES-GCM hardware is present, the AES-GCM cipher suites are
prioritised by default in crypto/tls. (Some servers, such as Google,
respect the client's preference between AES-GCM and ChaCha20-Poly1305.)

Fixes #17779.

Change-Id: I50de2be486f0b0b8052c4628d3e3205a1d54a646
Reviewed-on: https://go-review.googlesource.com/32871
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Some multipart data arrives in a stream, where subsequent parts may not
be ready yet. Read should return a complete part as soon as
possible.

Fixes #15431

Change-Id: Ie8c041b853f3e07f0f2a66fbf4bcab5fe9132a7c
Reviewed-on: https://go-review.googlesource.com/32032
Run-TryBot: Quentin Smith <quentin@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Cuts tests from 35 to 25 seconds.

Many of these could be parallel if the test runner were modified to
give each test its own workdir cloned from the tempdir files they
use. But later. This helps for now.

Updates #17751

Change-Id: Icc2ff87cca60a33ec5fd8abb1eb0a9ca3e85bf95
Reviewed-on: https://go-review.googlesource.com/32850
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #17812.

Change-Id: I08202165dd3f72ae04420e7b6129b8b689e74f5c
Reviewed-on: https://go-review.googlesource.com/32870Reviewed-by: Alan Donovan <adonovan@google.com>

Fixes #17818.

Change-Id: Id7242b0bdd5e1db254b44ae29900fc4f3362c743
Reviewed-on: https://go-review.googlesource.com/32828Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ibf73ee7be4591393f4e08d464edfa325c3ec2c11
Reviewed-on: https://go-review.googlesource.com/32798Reviewed-by: Ian Lance Taylor <iant@golang.org>

The tests all pass (for me at least) so I don't think there is any
reason not to enable them.

Change-Id: I96e71383e573273f442a849914cf6458ada14f82
Reviewed-on: https://go-review.googlesource.com/32855Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

ppc64le supports both internal and external linking so I don't
think there is any reason for it to skip this test.

Change-Id: I05c80cc25909c0364f0a1fb7d20766b011ea1ebb
Reviewed-on: https://go-review.googlesource.com/32854Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

On ppc64x, trampolines are used to resolve too-far
branches for internal linking.  The external linking,
solution on ppc64x is to split text sections when they
get too large, allowing the external linker to handle
the long branches.

On arm trampolines are generanted for too-far branches
for internal and external linking.  When the change
was made recently to enable trampolines for external linking
on arm, that broke the ppc64x fix for too-far branches
with external linking.

The fix adds a check to use trampolines only for internal
linking with ppc64x.

Fixes #17795

Change-Id: Icce968fb96545f10a913e07654514643bce96261
Reviewed-on: https://go-review.googlesource.com/32853
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>

Fixes #17815

Change-Id: I766082d28a14c77f5dfb6cd1974b86cb0a8fe31a
Reviewed-on: https://go-review.googlesource.com/32852Reviewed-by: Minux Ma <minux@golang.org>

Fixes #17811

Change-Id: I7bf9cbc5245417047ad28a14d9b9ad6592607d3d
Reviewed-on: https://go-review.googlesource.com/32774Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Was 2.3 seconds. Now 1.4 seconds.

Next win would be not running a child process and refactoring main so
it could be called from tests easily. But that would also require
rewriting the errchk written in Perl. This appears to be the last user
of errchk in the tree.

Updates #17751

Change-Id: Id7c3cec76f438590789b994e756f55b5397be07f
Reviewed-on: https://go-review.googlesource.com/32754
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Fixes #17797.

Change-Id: I544df81c4bcf3cbd36a793be40050f14f9a9974f
Reviewed-on: https://go-review.googlesource.com/32761Reviewed-by: Dominik Honnef <dominik@honnef.co>

net/fd_windows.go:121: syscall.WSABuf composite literal uses unkeyed fields

Change-Id: I91cbe38199d5b6828379a854d08f6ceaf687dd82
Reviewed-on: https://go-review.googlesource.com/32760
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #17805

Change-Id: I30d3e63a82b3690a76f2bb33d59ae34c62a7fa59
Reviewed-on: https://go-review.googlesource.com/32759
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

A few tests were using the global DefaultTransport implicitly.
Be explicit instead. And then make some parallel while I'm there.

Change-Id: I3c617e75429ecc8f6d23567d1470f5e5d0cb7cfd
Reviewed-on: https://go-review.googlesource.com/32758
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

These comments were originally introduced together with the changes
for alias declarations, and then reverted when we backed out alias
support.

Reintroduce them.

Change-Id: I3ef2c4f4672d6af8a900f5d73df273edf28d1a14
Reviewed-on: https://go-review.googlesource.com/32826Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This reverts commit 32db3f27.

Reason: Decision to back out current alias implementation.

For #16339.

Change-Id: Ib05e3d96041d8347e49cae292f66bec791a1fdc8
Reviewed-on: https://go-review.googlesource.com/32825Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This reverts commit 776a9010.

Reason: Decision to back out current alias implementation.

For #16339.

Change-Id: Icb451a122c661ded05d9293356b466fa72b965f3
Reviewed-on: https://go-review.googlesource.com/32824Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This reverts commit 57ae8330.

Reason: Decision to back out current alias implementation.

For #16339.

Change-Id: I7bcc04ac87ea3590999e58ff65a7f2e1e6c6bc77
Reviewed-on: https://go-review.googlesource.com/32823Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change-Id: I0520a37a48a56d231a8ac2dc58b2bf1762282760
Reviewed-on: https://go-review.googlesource.com/32795Reviewed-by: Ian Lance Taylor <iant@golang.org>

This reverts commit 59c63c71.

Reason: Decision to back out current alias implementation.

For #16339.

Change-Id: Idd135fe84b7ce4814cb3632f717736fc6985634c
Reviewed-on: https://go-review.googlesource.com/32822Reviewed-by: Chris Manghane <cmang@golang.org>

This reverts commit aa8c8e77.

Reason: Decision to back out current alias implementation.

For #16339.

Change-Id: I4db9a8d6b3625c794be9d2f1ff0e9c047f383d28
Reviewed-on: https://go-review.googlesource.com/32827
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Chris Manghane <cmang@golang.org>

Reason: Decision to back out current alias implementation.

Leaving import/export related code in place for now.

For #16339.

TBR=mdempsky

Change-Id: Ib0897cab2c1c3dc8a541f2efb9893271b0b0efe2
Reviewed-on: https://go-review.googlesource.com/32757Reviewed-by: Robert Griesemer <gri@golang.org>