If a program wants to evaluate math.Sqrt for any constant value
(for example, math.Sqrt(3)), we can replace that expression with
its evaluation (1.7320508075688772) at compile time, instead of
generating a SQRT assembly command or equivalent.

Adds tests that math.Sqrt generates the correct values. I also
compiled a short program and verified that the Sqrt expression was
replaced by a constant value in the "after opt" step.

Adds a short doc to the top of generic.rules explaining what the file
does and how other files interact with it.

Fixes #15543.

Change-Id: I6b6e63ac61cec50763a09ba581024adeee03d4fa
Reviewed-on: https://go-review.googlesource.com/27457Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>

Tell msan that the arguments to the traceback functions are initialized,
in case the traceback functions are compiled with -fsanitize=memory.

Change-Id: I3ab0816604906c6cd7086245e6ae2e7fa62fe354
Reviewed-on: https://go-review.googlesource.com/24856
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

I've also unexported a few symbols that weren't used outside the
package.

Updates #16818

Change-Id: I39d9d87b3eec30b88b4a17c1333cfbbfa6b3518f
Reviewed-on: https://go-review.googlesource.com/27468
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Otherwise flag.PrintDefaults will fail when it tries to determine
whether the default is the zero value.

Fixes #16694.

Change-Id: I253fbf11ffc0a9069fd48c2c3cf3074df53e3a03
Reviewed-on: https://go-review.googlesource.com/27003
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The optional fractional seconds overrides any range error
from the second parsing. Instead don't look for optional fractional
seconds if a range error has occured.

Change-Id: I27e0a2432740f6753668bd8833e48b9495bc4036
Reviewed-on: https://go-review.googlesource.com/27590
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Cleanup test code for symbolic links.

Change-Id: I25f561cd34dc4d120a4143f933619d233a6cffc5
Reviewed-on: https://go-review.googlesource.com/27573Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Cleanup test code for symbolic links.

Change-Id: I7a116e4d5c0e955578eca53c1af559e9092f60cd
Reviewed-on: https://go-review.googlesource.com/27572Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I384eac632a4a87c12977e56a7d7bad7614305c51
Reviewed-on: https://go-review.googlesource.com/25143
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #16802.

Change-Id: I41be7bb4e21e3beaa2136ee69771b0f455b2a7c6
Reviewed-on: https://go-review.googlesource.com/27417Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

On some error when using io.Copy with TCPConn, it displays an error
correlation like the following:

read tcp 192.0.2.1:1111->192.0.2.2:2222: read tcp [2001:db8::2]:2222->[2001:db8::3]:3333 read: connection reset by peer

the correlation "some error on reading after reading operation" looks a
bit confusing because the operation on the ReadFrom method of TCPConn is
actually "writing after reading." To clarify and avoid confusion, this
change sets "readfrom" to the Op field of outer-most OpError instead of
"read."

Change-Id: I6bf4e2e7247143fa54bbcf9cef7a8ae1ede1b35c
Reviewed-on: https://go-review.googlesource.com/25220Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I43f14cdd9eb4a1d5471fc88c1b4759ceb2c674cf
Reviewed-on: https://go-review.googlesource.com/24817
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Iabb25e97714d070c31c657559a97a3bfc979da18
Reviewed-on: https://go-review.googlesource.com/25403Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I7c809ec385b56ebb2ec784a1479d466df6ab4d1a
Reviewed-on: https://go-review.googlesource.com/27565Reviewed-by: Ian Lance Taylor <iant@golang.org>

This enables better packing when key and value
types have different alignments.

Cuts 57k off cmd/go.

Change-Id: Ifdd125264caccd7852d622382c94e4689e757978
Reviewed-on: https://go-review.googlesource.com/26669
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Change-Id: Ie2bef1c181a49d7a02ed8068894d2bd81fc5bafa
Reviewed-on: https://go-review.googlesource.com/27566Reviewed-by: Ian Lance Taylor <iant@golang.org>

This permits people to use -buildmode=c-archive to produce an archive
file that can be included in a PIE or shared library.

Change-Id: Ie340ee2f08bcff4f6fd1415f7d96d51ee3a7c9a1
Reviewed-on: https://go-review.googlesource.com/24180
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Add missing race and msan checks to reflect.typedmmemove and
reflect.typedslicecopy. Missing these checks caused the race detector
to miss races and caused msan to issue false positive errors.

Fixes #16281.

Change-Id: I500b5f92bd68dc99dd5d6f297827fd5d2609e88b
Reviewed-on: https://go-review.googlesource.com/24760
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

Keep flagInterpreter unchanged after flag parsing. This lets us replace
flagInterpreterSet with flagInterpreter != "".

Change-Id: Ifd2edbb2ce0011e97276ca18281b8ffbabde1c50
Reviewed-on: https://go-review.googlesource.com/27563
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I29fadde646095fa8507f239a339857bf53172c14
Reviewed-on: https://go-review.googlesource.com/27418Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Android timezones are in a packed format, different from the separate
files of a regular Unix system. This CL contain the necessary code to
parse the packed tzdata file and extract time zones from it. It also
adds a basic test to ensure the new parser works.

Fixes #13581

Change-Id: Idebe73726c3d4c2de89dd6ae1d7d19f975207500
Reviewed-on: https://go-review.googlesource.com/24494Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fetch the current time in nanoseconds, not microseconds, by using
clock_gettime rather than gettimeofday.

Updates #11222

Change-Id: I1c2c1b88f80ae82002518359436e19099061c6fb
Reviewed-on: https://go-review.googlesource.com/26790Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Minux Ma <minux@golang.org>

os package and path/filepath package have duplicated code for
checking symlink supports in test code.
This CL tries to simplify such test code.

Change-Id: I0371488337f5e951eca699852daab9ccb16ddd62
Reviewed-on: https://go-review.googlesource.com/27331
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This permits the error message to distinguish between a context that was
canceled and a context that timed out.

Updates #16381.

Change-Id: I3994b98e32952abcd7ddb5fee08fa1535999be6d
Reviewed-on: https://go-review.googlesource.com/24978
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

No functional changes.

Change-Id: I0961227e8a7be2d7c611452896843b6955303fa6
Reviewed-on: https://go-review.googlesource.com/26768Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

This sort is now only reachable for constant clauses
for a non-interface switch expression value.

Refactor a bit so that the few tests that remain
are concise and easy to read.

Add a test that string length takes priority
over built-in string order.

Change-Id: Iedaa11ff77049d5ad1bf14f54cbb8c3411d589a7
Reviewed-on: https://go-review.googlesource.com/26767
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This is simpler than the sorting technique.
It also allows us to simplify or eliminate
some of the sorting decisions.

Most important, sorting will not work when case clauses
represent ranges of integers: There is no correct
sort order that allows overlap detection by comparing
neighbors. Using a map allows of a cheap, simple
approach to ranges, namely to insert every int
in the map. The equivalent approach for sorting
means juggling temporary Nodes for every int,
which is a lot more expensive.

Change-Id: I84df3cb805992a1b04d14e0e4b2334f943e0ce05
Reviewed-on: https://go-review.googlesource.com/26766
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

The implementations are going to start diverging more.
Instead of more if clauses and empty parameters,
specialize.

Change-Id: I44584450592e8c9f72a10d8ada859c07e9d9aa19
Reviewed-on: https://go-review.googlesource.com/26764
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

We used to have separate kinds for the default
case and the nil type case. Now that those are
gone, we can use a simple bool instead.

Change-Id: I65488e945df68178e893cddd2e091ebb6e32ef4d
Reviewed-on: https://go-review.googlesource.com/26763
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Switch lowering splits each case expression out
into its own OCASE node.

Change-Id: Ifcb72b99975ed36da8540f6e43343e9aa2058572
Reviewed-on: https://go-review.googlesource.com/26769
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This is a bit simpler than playing sorting games,
and it is clearer that it generates errors
in the correct (source) order.

It also allows us to simplify sorting.

It also prevents quadratic error messages for
(pathological) inputs with many duplicate type cases.

While we’re here, refactoring deduping into separate functions.

Negligible compilebench impact.

Fixes #15912.

Change-Id: I6cc19edd38875389a70ccbdbdf0d9b7d5ac5946f
Reviewed-on: https://go-review.googlesource.com/26762
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change-Id: If443ffb50b140c466dcf4cc5340f44948bfa46a9
Reviewed-on: https://go-review.googlesource.com/26765Reviewed-by: Matthew Dempsky <mdempsky@google.com>

example for httptest.Recorder was inspecting Recoder directly.
Using Result() to convert Recorder into a http.Response yields a much
better user experience.

Closes #16837

Change-Id: Id0e636c12cd6adb1ba11f89953ff2b0f43758cf3
Reviewed-on: https://go-review.googlesource.com/27495Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

CL 27473 accidentally changed `!Debug['I']` to `*flagInterpreter != ""`.
Since the old `Debug['I']` was set when the new *flagInterpreter was
set, this inverted the sense of the condition. The effect was to always
ignore the cgo_dynamic_interpreter setting from runtime/cgo. This worked
OK when the default interpreter was the correct one, but failed when it
was not, as is currently the case on, at least, PPC64 and ARM.

This CL restores the old behavior by using a separate variable to track
whether the -I flag was used, just as we used to.

Change-Id: Icf9b65fa41349ed2e4de477fec0a557ef1eb8189
Reviewed-on: https://go-review.googlesource.com/27562
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

My flags change reversed the meaning of -s within mips64's
linker code. This should fix that.

Change-Id: Ia24002469e557fb29badfd830134e61c1dd7e16e
Reviewed-on: https://go-review.googlesource.com/27555Reviewed-by: Minux Ma <minux@golang.org>

Replace ad-hoc encoding of export version info with a
more systematic approach.

Continue to read (but not write) the Go1.7 format for backward-
compatibility. This will avoid spurious errors with old installed
packages.

Fixes #16244.

Change-Id: I945e79ffd5e22b883250f6f9fac218370c2505a2
Reviewed-on: https://go-review.googlesource.com/27452Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Updates #16795

Change-Id: I0bcc34bb5a92a2c480aebfb0eb6ba57bcc7f7cfd
Reviewed-on: https://go-review.googlesource.com/27551Reviewed-by: Ian Lance Taylor <iant@golang.org>

This adds some additional rules to improve loads and
stores for ppc64x.

Change-Id: I96b99c3a0019e6ac5393910c086f58330a04fc5a
Reviewed-on: https://go-review.googlesource.com/27354
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

Rather than juggle default and nil cases as part
of a slice, handle them explicitly.

Change-Id: I97b200c9d3f23fe1a438acdbf3d13b0cf7e0851e
Reviewed-on: https://go-review.googlesource.com/26761
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Fixes #15911.

Change-Id: I500533484de61aa09abe4cecb010445e3176324e
Reviewed-on: https://go-review.googlesource.com/26760
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change-Id: Iacedb792c73591b7fd75e836aab8e0e117c8e738
Reviewed-on: https://go-review.googlesource.com/27494
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>