Currently there's an invariant in the runtime wherein the heap lock
can only be acquired on the system stack, otherwise a self-deadlock
could occur if the stack grows while the lock is held.

This invariant is upheld and documented in a number of situations (e.g.
allocManual, freeManual) but there are other places where the invariant
is either not maintained at all which risks self-deadlock (e.g.
setGCPercent, gcResetMarkState, allocmcache) or is maintained but
undocumented (e.g. gcSweep, readGCStats_m).

This change adds go:systemstack to any function that acquires the heap
lock or adds a systemstack(func() { ... }) around the critical section,
where appropriate. It also documents the invariant on (*mheap).lock
directly and updates repetitive documentation to refer to that comment.

Fixes #32105.

Change-Id: I702b1290709c118b837389c78efde25c51a2cafb
Reviewed-on: https://go-review.googlesource.com/c/go/+/177857
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Austin Clements <austin@google.com>

I have seen code that literally copied the example like this:

    if strings.ContainsAny(s, "1 & 2 & 3") {

The developer apparently thought that this is the way to
specify multiple characters and I noticed this pattern
being used in the example. Let's update the example so
that it's clear how multiple Unicode code points should
be specified.

Change-Id: Id4d780555e521af62fb787a7950be1e60848cd95
Reviewed-on: https://go-review.googlesource.com/c/go/+/178737Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ic5b01c0a6912d87e812331d6525939df8f525cca
GitHub-Last-Rev: b6ffefcf8f2ec1ed7ee13f36e8fef6af965ba332
GitHub-Pull-Request: golang/go#29993
Reviewed-on: https://go-review.googlesource.com/c/go/+/160417Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: If001d8f7e657e01711653827a170904932839e34
Reviewed-on: https://go-review.googlesource.com/c/go/+/178721
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ib7be503a46f3609ea29464569e57e1f620e97a53
GitHub-Last-Rev: a43cffe45f3b9d208028f7682088cbe537d6deca
GitHub-Pull-Request: golang/go#30007
Reviewed-on: https://go-review.googlesource.com/c/go/+/160431
Run-TryBot: Leon Klingele <git@leonklingele.de>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The typed arrays returned by TypedArrayOf were backed by WebAssembly
memory. They became invalid each time we grow the WebAssembly memory.
This made them very error prone and hard to use correctly.

This change removes TypedArrayOf completely and instead introduces
CopyBytesToGo and CopyBytesToJS for copying bytes between a byte
slice and an Uint8Array. This breaking change is still allowed for
the syscall/js package.

Fixes #31980.
Fixes #31812.

Change-Id: I14c76fdd60b48dd517c1593972a56d04965cb272
Reviewed-on: https://go-review.googlesource.com/c/go/+/177537
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Utilize KDSA when available. This guarantees constant time operation on all three curves mentioned,
and is faster than conventional assembly. The IBM Z model(s) that support KDSA as used in this CL
are not yet publicly available, and so we are unable to release performance data at this time.

Change-Id: I85360dcf90fe42d2bf32afe3f638e282de10a518
Reviewed-on: https://go-review.googlesource.com/c/go/+/174437
Run-TryBot: Michael Munday <mike.munday@ibm.com>
Reviewed-by: Michael Munday <mike.munday@ibm.com>

This is now recognized and recommended by GitHub.

Fixes #32201

Change-Id: Iafb5ef1b2bee5f021a711b0b758aaf6a74758c5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/178697Reviewed-by: Ian Lance Taylor <iant@golang.org>

This test was designed for #15609 and didn't consider nacl. It's not
worth adding new +build-guarded assembly files in issue15609.dir for
nacl, especially as nacl is going away.

Fixes #32206

Change-Id: Ic5bd48b4f790a1f7019100b8a72d4688df75512f
Reviewed-on: https://go-review.googlesource.com/c/go/+/178698
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Replaces putUint{32,64} functions in crypto/sha* packages with the
equivalent functions encoding/binary.BigEndian.PutUint{32,64}.

Change-Id: I9208d2125202ea9c97777560e6917d21893aced0
Reviewed-on: https://go-review.googlesource.com/c/go/+/156117Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ia42a4a658e4207cc1f036f2faeac011e71edad77
GitHub-Last-Rev: b384f81799fcd404f53647d8a3015487ea240c6f
GitHub-Pull-Request: golang/go#30012
Reviewed-on: https://go-review.googlesource.com/c/go/+/160436
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Encodes non-WSP CTL and non-US-ASCII UTF-8 characters using syntax specified in RFC 2231.

Fixes #7668
Fixes #9624

Change-Id: I433f167c5bdd84a7f811ac0410b08b10790e0d9f
GitHub-Last-Rev: 9c77146760341fdb3af35c1b94d4ee00ffb0daae
GitHub-Pull-Request: golang/go#29328
Reviewed-on: https://go-review.googlesource.com/c/go/+/154760Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Float formatting uses a multiprecision fallback path where Grisu3
algorithm fails. This has a bug during the rounding phase: the
difference between the decimal value and the upper bound is examined
byte-by-byte and doesn't properly handle the case where the first
divergence has a difference of 1.

For instance (using an example from #29491), for the number
498484681984085570, roundShortest examines the three decimal values:

lower: 498484681984085536
d:     498484681984085568
upper: 498484681984085600

After examining the 16th digit, we know that rounding d up will fall
within the bounds unless all remaining digits of d are 9 and all
remaining digits of upper are 0:

d:     ...855xx
upper: ...856xx

However, the loop forgets that d and upper have already diverged and
then on the next iteration sees that the 17th digit of d is actually
lower than the 17th digit of upper and decides that we still can't round
up:

d:     ...8556x
upper: ...8560x

Thus the original value is incorrectly rounded down to
498484681984085560 instead of the closer (and equally short)
498484681984085570.

Thanks to Brian Kessler for diagnosing this bug.

Fix it by remembering when we've seen divergence in previous digits.

This CL also fixes another bug in the same loop: for some inputs, the
decimal value d or the lower bound may have fewer digits than the upper
bound, yet the iteration through the digits starts at i=0 for each of
them. For instance, given the float64 value 1e23, we have

d:      99999999999999991611392
upper: 100000000000000000000000

but the loop starts by comparing '9' to '1' rather than '0' to '1'.

I haven't found any cases where this second bug causes incorrect output
because when the digit comparison fails on the first loop iteration the
upper bound always has more nonzero digits (i.e., the expression
'i+1 < upper.nd' is always true).

Fixes #29491

Change-Id: I58856a7a2e47935ec2f233d9f717ef15c78bb2d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/157697
Run-TryBot: Caleb Spare <cespare@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rémy Oudompheng <remyoudompheng@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This CL changes the default module download and module verification mechanisms
to use the Go module mirror and Go checksum database run by Google.
See https://proxy.golang.org/privacy for the services' privacy policy.
(Today, that URL is a redirect to Google's standard privacy policy,
which covers these services as well. If we publish a more specific
privacy policy just for these services, that URL will be updated to
display or redirect to it.)

See 'go help modules' and 'go help modules-auth' for details (added in this CL).

To disable the mirror and checksum database for non-public modules:

	go env -w GONOPROXY=*.private.net,your.com/*
	go env -w GONOSUMDB=*.private.net,your.com/*

(If you are using a private module proxy then you'd only do the second.)

If you run into problems with the behavior of the go command when using
the Go module mirror or the Go checksum database, please file issues at
https://golang.org/issue/new, so that we can address them for the
Go 1.13 release.

For #25530.

This CL also documents GONOPROXY.
Fixes #32056.

Change-Id: I2fde82e071742272b0842efd9580df1a56947fec
Reviewed-on: https://go-review.googlesource.com/c/go/+/178179
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Apologies for the the nitpicky PR. I believe there is a minor typo in the documentation of `MaxScanTokenSize`, which confused me for a moment when I went to search for the referenced method, `Scan.Buffer`. Thanks!

Change-Id: I5d21e77276285206497fe75291001032c255cace
GitHub-Last-Rev: 635e35c0191c11f2b6966b5e58cf91a1064099da
GitHub-Pull-Request: golang/go#32193
Reviewed-on: https://go-review.googlesource.com/c/go/+/178637Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #31961

Change-Id: I9db9ecfd2f8ca7cf51df4413a6e0d66de5da7043
Reviewed-on: https://go-review.googlesource.com/c/go/+/178457
Run-TryBot: Agniva De Sarker <agniva.quicksilver@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

The new slice function returns the result of slicing its first argument by
the following arguments. Thus {{slice x 1 3}} is, in Go syntax, x[1:3].
Each sliced item must be a string, slice, or array.

Closed #30153

RELNOTE=yes

Change-Id: I63188c422848cee3d383a64dc4d046e3a1767c63
Reviewed-on: https://go-review.googlesource.com/c/go/+/161762Reviewed-by: Rob Pike <r@golang.org>

Like panicking and erroring - wrapErrs should always be reset to
the default false. wrapErrs should only be true when set by Errorf.

Change-Id: I4d51cc2f0905109e232b0983dc5331bd34f138bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/178517
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>

Currently, some tests under test/fixedbugs never run:

	$ for d in test/fixedbugs/*.dir; do
	  ! test -f "${d%.dir}.go" && echo "$d"
	done
	test/fixedbugs/issue15071.dir
	test/fixedbugs/issue15609.dir
	test/fixedbugs/issue29612.dir

Because they missed the corresponding ".go" file, so "go run run.go"
will skip them.

Add missing ".go" files for those tests to make sure they will be
collected and run.

While at it, add another action "runindir", which does "go run ."
inside the t.goDirName then check the output.

Change-Id: I88000b3663a6a615d90c1cf11844ea0377403e3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/177798
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

We want the builders to be able to cross-compile test binaries for a
few of the super slow builders that require either slow hardware or
slow full CPU emulation.

Updates golang/go#31217

Change-Id: I8d33b18efaf788f6f131354b2917ac9738ca975e
Reviewed-on: https://go-review.googlesource.com/c/go/+/178399
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I8827cef0f57459384329c50c51795350da0ede4b
GitHub-Last-Rev: c9ad9e12b5a0fff47c21a8c299b762b64b8c9c7c
GitHub-Pull-Request: golang/go#30010
Reviewed-on: https://go-review.googlesource.com/c/go/+/160434
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

This keeps transparency of a wrapped image.Image even after it is encoded.

Fixes #30995

Change-Id: I1f7ac98b1741f83ed740f6eda6c36b7e9b16e5af
Reviewed-on: https://go-review.googlesource.com/c/go/+/177377Reviewed-by: Hayato Kawakami <kawakami.ozone@gmail.com>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Run-TryBot: Benny Siegert <bsiegert@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

As an optimization, function literals capture variables by value when
they're not assigned and their address has not been taken. Because
result parameters are implicitly assigned through return statements
(which do not otherwise set the "assigned" flag), result parameters
are explicitly handled to always capture by reference.

However, the logic was slightly mistaken because it was only checking
if the variable in the immediately enclosing context was a return
parameter, whereas in a multiply-nested function literal it would
itself be another closure variable (PAUTOHEAP) rather than a return
parameter (PPARAMOUT).

The fix is to simply test the outermost variable, like the rest of the
if statement's tests were already doing.

Fixes #32175.

Change-Id: Ibadde033ff89a1b47584b3f56c0014d8e5a74512
Reviewed-on: https://go-review.googlesource.com/c/go/+/178541
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #29662

Change-Id: I38b52b96712e44a323333da17dbbc883516773b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/177900Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

To a fifth reading of the relevant docs, it looks like

1) a constraint dictionary with no policy applies to all of them;
2) multiple applying constraint dictionaries should have their results OR'd;
3) untrusted certificates in the keychain should be used for chain building.

This fixes 1), approximates 2) and punts on 3).

Fixes #30672
Fixes #30471

Change-Id: Ibbaabf0b77d267377c0b5de07abca3445c2c2302
Reviewed-on: https://go-review.googlesource.com/c/go/+/178539Reviewed-by: Adam Langley <agl@golang.org>

Note how untrustedData is never NULL, so loadSystemRoots was checking
the wrong thing.

Also, renamed the C function to CopyPEMRoots to follow the
CoreFoundation naming convention on ownership.

Finally, redirect all debug output to standard error.

Change-Id: Ie80abefadf8974a75c0646aa02fcfcebcbe3bde8
Reviewed-on: https://go-review.googlesource.com/c/go/+/178538Reviewed-by: Adam Langley <agl@golang.org>

CFDictionaryGetValueIfPresent does not take ownership of the value, so
releasing the properties dictionary before passing the value to CFEqual
can crash. Not really clear why this works most of the time.

See https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html

Fixes #28092
Hopefully fixes #30763

Change-Id: I5ee7ca276b753a48abc3aedfb78b8af68b448dd4
Reviewed-on: https://go-review.googlesource.com/c/go/+/178537Reviewed-by: Adam Langley <agl@golang.org>

Shorten some of the longest tests that run during all.bash.
Removes 7r 50u 21s from all.bash.

After this change, all.bash is under 5 minutes again on my laptop.

For #26473.

Change-Id: Ie0460aa935808d65460408feaed210fbaa1d5d79
Reviewed-on: https://go-review.googlesource.com/c/go/+/177559
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Each different file that does import "C" must be compiled
and analyzed separately by cgo. Having fewer files import "C"
reduces the cost of building the test. This is especially important
because this test is built and run four different times (with different
settings) during all.bash.

go test -c in this directory used to take over 20 seconds on my laptop.
Now it takes under 5 seconds.

Removes 23.4r 29.0u 21.5s from all.bash.

For #26473.

Change-Id: Ie7cb7b0d9d6138ebd2eb548d0d8ea6e409ae10b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/177558
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

First, remove the randomization of initialization order.

Then, revert to source code order instead of sorted package path order.

This restores the behavior that was in 1.12.

A larger change which will implement the suggestion in #31636 will
wait for 1.14. It's too complicated for 1.13 at this point (it has
tricky interactions with plugins).

Fixes #31636

Change-Id: I35b48e8cc21cf9f93c0973edd9193d2eac197628
Reviewed-on: https://go-review.googlesource.com/c/go/+/178297
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

If the char class is 0x0-0x10ffff we mistakenly would String that to `[^]`,
which is not a valid regex.

Fixes #31807

Change-Id: I9ceeaddc28b67b8e1de12b6703bcb124cc784556
Reviewed-on: https://go-review.googlesource.com/c/go/+/175679Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The Wrapper type no longer exists.

Change-Id: I21051f26c6722a957295819f2f385f2bbd0db355
Reviewed-on: https://go-review.googlesource.com/c/go/+/177618Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #31267

Change-Id: I91e4aa8cf9d797689cb9612d0fe3bf1bb3ad15a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/178177Reviewed-by: Keith Randall <khr@golang.org>

Gerrit is complaining about pushes that affect these files
and forcing people to use -o nokeycheck, which defeats
the point of the check. Hide the keys from this kind of scan
by marking them explicitly as testing keys.

This is a little annoying but better than training everyone
who ever edits one of these test files to reflexively override
the Gerrit check.

The only remaining keys explicitly marked as private instead
of testing are in examples, and there's not much to do
about those. Hopefully they are not edited as much.

Change-Id: I4431592b5266cb39fe6a80b40e742d97da803a0b
Reviewed-on: https://go-review.googlesource.com/c/go/+/178178
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Build a single binary containing all the TestPointerChecks
instead of building many small binaries,
each with its own cgo+compile+link invocation.
This cuts 'go test -run=TestPointerChecks'
from 6.7r 35.5u 26.1s to 2.1r 2.1u 1.4s.

Move as many cgo checks as possible into fewer test files
for TestReportsTypeErrors too.
This cuts 'go test -run=TestReportsTypeErrors'
from 2.1r 6.7u 6.7s to 1.5r 2.5u 2.5s.

After this change, all.bash runs in ~4:30 on my laptop.

For #26473.

Change-Id: I3787448b03689a1f62dd810957ab6013bb75582f
Reviewed-on: https://go-review.googlesource.com/c/go/+/177599
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Cuts api test time from 12.7r 26.2u 14.2s to 7.5r 12.1u 2.2s.

After this change, all.bash runs in ~4:36 on my laptop.

For #26473.

Change-Id: I4211e6afcd7ab61a4ed2c9a2aa5ac1ea04982695
Reviewed-on: https://go-review.googlesource.com/c/go/+/177597
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

typecheck type alias always replaces the original definition of the symbol.
This is wrong behavior because if the symbol's definition is replaced by a
local type alias, it ends up being written to compiled file as an alias,
instead of the original type.

To fix, only replace the definition of symbol with global type alias.

Fixes #31959

Change-Id: Id85a15e8a9d6a4b06727e655a95dc81e63df633a
Reviewed-on: https://go-review.googlesource.com/c/go/+/177378
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Fixes #31896

Change-Id: I228a809568cd37c599987f9f1e99df5c229e6c9b
Reviewed-on: https://go-review.googlesource.com/c/go/+/176112
Run-TryBot: Caleb Spare <cespare@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Change-Id: Ie299a5eca6f6a7c5a37c00ff0de7ce322450375b
Reviewed-on: https://go-review.googlesource.com/c/go/+/178123Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This change modifies Go to include image/webp as a built-in mime type for the .webp file extension.

Change-Id: Id46d34fac8cc859ddd69aa8669294815654214f8
GitHub-Last-Rev: f191e1c325126e2caeb3123c912131ce5236542b
GitHub-Pull-Request: golang/go#32157
Reviewed-on: https://go-review.googlesource.com/c/go/+/178317Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>