AIX doesn't allow to mmap an already mmap address. The previous way to
deal with this behavior was to munmap before calling mmap again.
However, mprotect syscall is able to change protections on a memory
range. Thus, memory mapped by sysReserve can be remap using it. Note
that sysMap is always called with a non-nil pointer so mprotect is
always possible.

Updates: #35451

Change-Id: I1fd1e1363d9ed9eb5a8aa7c8242549bd6dad8cd0
Reviewed-on: https://go-review.googlesource.com/c/go/+/207237Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

Fixes #28012

Change-Id: I711ebaabf63194e3d2c608d829da49c51a294d74
Reviewed-on: https://go-review.googlesource.com/c/go/+/210286
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ic79d97c2aa107c0e5c4a8906ad757b0390228bef
Reviewed-on: https://go-review.googlesource.com/c/go/+/210417Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Some Linux distributions will continue to provide 5.3.x kernels for a
while rather than 5.4.x.

Updates #35777

Change-Id: I493ef8338d94475f4fb1402ffb9040152832b0fd
Reviewed-on: https://go-review.googlesource.com/c/go/+/210299Reviewed-by: Austin Clements <austin@google.com>

Fixes #34930

Change-Id: Ie0ddd8de6e40f5a192c4d2267399126e449fe5f5
Reviewed-on: https://go-review.googlesource.com/c/go/+/210340
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

CL 209899 worked around an issue that corrupts vector registers in
recent versions of the Linux kernel by mlocking the top page of every
signal stack on amd64. However, the underlying issue also affects the
XMM registers on 386. This CL applies the mlock fix to both amd64 and
386.

Fixes #35777 (again).

Change-Id: I9886f2dc4c23625421296bd5518d5fd3288bfe48
Reviewed-on: https://go-review.googlesource.com/c/go/+/210345
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

slice, type, and select should all go with "a", not "an", since they all
start with consonant sounds.

Change-Id: I57e96dcbdc571dc21e24096779f2f756ec81103e
Reviewed-on: https://go-review.googlesource.com/c/go/+/210124Reviewed-by: Robert Griesemer <gri@golang.org>

The last paragraph in golang.org/doc/install/source#fetch is missing a
p tag, so it doesn't get formatted with the 'max-width: 50rem' like
all the other text in the page.

Add it.

Change-Id: I1a981dd2afde561b4ab21bd90ad99b3a146111f6
Reviewed-on: https://go-review.googlesource.com/c/go/+/210122Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Uses 2 channels to synchronize that test, because
relying on sleeps creates flaky behavior, thus:

a) 1 buffered channel to send back the last spurious line
without having to reason about "happens before" behavior
a) 1 buffered channel at the end of the handler; it'll
be controlled by whether we expect to timeout or not,
but will always be closed when the test ends

Fixes #35051

Change-Id: Iff735aa8d1ed9de8d92b792374ec161cc0a72798
Reviewed-on: https://go-review.googlesource.com/c/go/+/208477
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Fix a minor typo in the TLS handshake comment.

Change-Id: I0fd243e5440f6c77c97e844e6669a7974a2c8798
GitHub-Last-Rev: 21e91a1a48e8a9200e6fca89a988e1383ded7bb2
GitHub-Pull-Request: golang/go#36030
Reviewed-on: https://go-review.googlesource.com/c/go/+/210289Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Replaced modules require only valid import paths, not full
module paths that can be fetched with 'go get'.

The 'go' command does not in general reject manually-edited go.mod
files with these paths, so 'go mod edit' should not reject them
either.

Fixes #30513

Change-Id: I4f1a5c65937f91d41478f8d218c8018e0c70f320
Reviewed-on: https://go-review.googlesource.com/c/go/+/210343
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

CL 210338 suppressed duplication for import paths mentioned in an
ImportMissingError.

Unfortunately, that broke one of the cases in
cmd/go/internal/modload.TestImport, and the new error message is still
kind of awkward anyway.

Let's revert that part of the change — we can try again with more
coverage for that case.

Updates #35986

Change-Id: Ib0858aec4f89a7231e32c35ec876da80d80f2098
Reviewed-on: https://go-review.googlesource.com/c/go/+/210342
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

This location was missed in CL 204521.

Updates #33326
Updates #33848

Change-Id: I0ece6d9b37548d8abb54f79c69be5548a0428c76
Reviewed-on: https://go-review.googlesource.com/c/go/+/210341
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

There may be gaps between non-writeable and writeable PT_LOAD
segments, and the gaps may be large as the segments may have
large alignment. Don't count those gaps in file size comparison.

Fixes #36023.

Change-Id: I68582bdd0f385ac5c6f87d485d476d06bc96db19
Reviewed-on: https://go-review.googlesource.com/c/go/+/210180
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

If the path looks like it belongs in GOROOT/src and isn't there, we
should mention that in the error message — instead of the fact
that the path is not a valid module path, which the user likely
already knows.

Fixes #34769
Fixes #35734

Change-Id: I3589336d102e420a5ad3bf246816e29f3cbe6d71
Reviewed-on: https://go-review.googlesource.com/c/go/+/210339
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

There is a part in the comment that points to a non-existent file.
It seems to have been overlooked in following PR.
https://go-review.googlesource.com/c/go/+/98518/

Change-Id: I21dbfbd270c654d5cd7fa88d114a356862612d90
Reviewed-on: https://go-review.googlesource.com/c/go/+/210298Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

get.RepoRootForImportPath now returns errors that satisfy
load.ImportPathError in cases where the import path appears in the
messages. (The import path probably should appear in all errors from
this function, but this CL does not change these errors).

Changed modfetch.notExistError to be a wrapper (with an Unwrap method)
instead of a string. This means errors.As works with notFoundError and
ImportPathError.

ImportMissingError no longer prints the package path if it wraps an
ImportPathError.

TestMissingImportErrorRepetition no longer counts the package path
within a URL (like https://...?go-get=1).

Fixes #35986

Change-Id: I38f795191c46d04b542c553e705f23822260c790
Reviewed-on: https://go-review.googlesource.com/c/go/+/210338
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

This test was recently added in CL 209961.

Apparently Windows can't seek a directory filehandle?

And move the test from test/fixedbugs (which is mostly for compiler bugs) to
an os package test.

Updates #36019

Change-Id: I626b69b0294471014901d0ccfeefe5e2c7651788
Reviewed-on: https://go-review.googlesource.com/c/go/+/210283
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Currently, we're ignoring failures to mlock signal stacks in the
workaround for #35777. This means if your mlock limit is low, you'll
instead get random memory corruption, which seems like the wrong
trade-off.

This CL checks for mlock failures and panics with useful guidance.

Updates #35777.

Change-Id: I15f02d3a1fceade79f6ca717500ca5b86d5bd570
Reviewed-on: https://go-review.googlesource.com/c/go/+/210098
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

If one of the helper goroutine panics, the main goroutine call to Wait
may hang forever waiting for something to call Done. Put that call in
a goroutine like the others.

Fixes #35774

Change-Id: I8d2b58d8f473644a49a95338f70111d4e6ed4e12
Reviewed-on: https://go-review.googlesource.com/c/go/+/210218
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

This change replaces

buf := [HUGE_CONST]*T)(unsafe.Pointer(p))[:]

with

buf := [HUGE_CONST]*T)(unsafe.Pointer(p))[:n:n]

Pointer p points to n of T elements. New unsafe pointer conversion
logic verifies that both first and last elements point into the same
Go variable.

This change replaces [:] with [:n:n] to please pointer checker.
According to @mdempsky, compiler specially recognizes when you
combine a pointer conversion with a full slice operation in a single
expression and makes an exception.

After this, only one failure in net remains when running:

go test -a -short -gcflags=all=-d=checkptr std cmd

Updates #34972

Change-Id: I2c8731650c856264bc788e4e07fa0530f7c250fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/208617
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change package qualification to print the full package path for packages
that have non-unique names (that is, where multiple different packages
have the same name). Use the package name as qualifier in all other cases
(but don't print any qualification if we're talking about the package
being type-checked).

This matches the behavior of the compiler.

Fixes #35895.

Change-Id: I33ab8e7adfae1378907c01e33cabda114f65887f
Reviewed-on: https://go-review.googlesource.com/c/go/+/209578
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

There should be no space after comma.

Change-Id: I6a5c85a386d9d1611b71d5b15a31a00c24c316b4
Reviewed-on: https://go-review.googlesource.com/c/go/+/210120
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Give the runtime more of a chance to do other work in a tight loop.

Fixes #34693

Change-Id: I8df6173d2c93ecaccecf4520a6913b495787df78
Reviewed-on: https://go-review.googlesource.com/c/go/+/210217
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Currently, a block's control instruction gets the liveness info
of the last Value in the block. However, for an empty block, the
control instruction gets the invalid liveness info and therefore
not preemptible. One example is empty infinite loop, which has
only a control instruction. The control instruction being non-
preemptible makes the whole loop non-preemptible.

Fix this by using a different, preemptible liveness info for
empty block's control. We can choose an arbitrary preemptible
liveness info, as at run time we don't really use the liveness
map at that instruction.

As before, if the last Value in the block is non-preemptible, so
is the block control. For example, the conditional branch in the
write barrier test block is still non-preemptible.

Also, only update liveness info if we are actually emitting
instructions. So zero-width Values' liveness info (which are
always invalid) won't affect the block control's liveness info.
For example, if the last Values in a block is a tuple-generating
operation and a Select, the block control instruction is still
preemptible.

Fixes #35923.

Change-Id: Ic5225f3254b07e4955f7905329b544515907642b
Reviewed-on: https://go-review.googlesource.com/c/go/+/209659
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>

Count Values with side effects but no use as live, and don't fuse
branches that contain such Values. (This can happen e.g. when it
is followed by an infinite loop.) Otherwise this may lead to
miscompilation (side effect fired at wrong condition) or ICE (two
stores live simultaneously).

Fixes #36005.

Change-Id: If202eae4b37cb7f0311d6ca120ffa46609925157
Reviewed-on: https://go-review.googlesource.com/c/go/+/210179Reviewed-by: Keith Randall <khr@golang.org>

Updates #24715

Change-Id: Ie6421cf2d599740bbb0576bcc37bd8ddf5af3961
Reviewed-on: https://go-review.googlesource.com/c/go/+/210119Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The newline was dropped during the refactor in CL 194617.

Fixes #35984

Change-Id: I7e0d7aa2d7a4d1f44898921f8bb40401620d78b2
Reviewed-on: https://go-review.googlesource.com/c/go/+/209965
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

If we aren't able to load imports from one file in a package due to a
parse error (scanner.ErrorList), 'go list -e' should still list
imports in other files.

Fixes #35973

Change-Id: I59f171877949bb7afaf252b6c8a970de22e60c7a
Reviewed-on: https://go-review.googlesource.com/c/go/+/210097
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

The first Readdirnames calls opendir and caches the result.
The behavior of that cached opendir result isn't specified on a seek
of the underlying fd. Free the opendir result on a seek so that
we'll allocate a new one the next time around.

Also fix wasm behavior in this regard, so that a seek to the
file start resets the Readdirnames position, regardless of platform.

p.s. I hate the Readdirnames API.

Fixes #35767.

Change-Id: Ieffb61b3c5cdd42591f69ab13f932003966f2297
Reviewed-on: https://go-review.googlesource.com/c/go/+/209961
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This issue was fixed by earlier improvements to error handling when
loading modules.

Fixes #34829

Change-Id: I4cf4e182a7381f8b5c359179d90bd02491ea7911
Reviewed-on: https://go-review.googlesource.com/c/go/+/209037
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Not all closed issues in a given minor milestone are included in that
release, only the ones that have been labeled as CherryPickApproved are.

Update the links to the GitHub issue tracker to include a filter on the
CherryPickApproved label, so that the default view shows only the
backports that were included in a given release. This should more useful
to most people than seeing all backports (considered and approved).

Do this only for Go 1.9.1 and newer releases, as that is when we started
using the CherryPickCandidate and CherryPickApproved labels.

Fixes #35988

Change-Id: I51e07c1bc3ab9c4a5744e8f668c5470adf78bffe
Reviewed-on: https://go-review.googlesource.com/c/go/+/209918Reviewed-by: Alexander Rakoczy <alex@golang.org>

Change-Id: I191ac2a2b469c6179d22d66c15f2d96ecb3d0902
Reviewed-on: https://go-review.googlesource.com/c/go/+/209970Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

CL 209077 updated bundled http2 to x/net git rev ef20fe5d7 without
bumping the go.mod version.

Identified with the new go/packages based cmd/bundle from CL 189818.

$ go get golang.org/x/net@ef20fe5d7
$ go mod tidy
$ go mod vendor
$ go generate -run bundle std # with CL 189818

Updates #32031

Change-Id: I581d35f33e2adafb588b2b0569648039187234a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/209901
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Remove documentation reference to gcCopySpans(), as that function was
removed in https://golang.org/cl/30537

Fixes #35683

Change-Id: I7fb7c6cc60bfb3a133a019a20eb3f9d4c7627b31
Reviewed-on: https://go-review.googlesource.com/c/go/+/209917Reviewed-by: Austin Clements <austin@google.com>

The Perm function return 0 or 1 or 2 or 3. 4 is not returned,
so that changed the argument to 5.

Change-Id: Ic980c71a9f29f522bdeef4fce70a6c2dd136d791
Reviewed-on: https://go-review.googlesource.com/c/go/+/209777Reviewed-by: Ian Lance Taylor <iant@golang.org>

Otherwise we leave a gap at the start of Segrelrodata equal to the
size of the read-only non-relro data, which causes -buildmode=pie
executables to be noticeably larger than -buildmode=exe executables.

Change-Id: I98956ef29d5b7a57ad8e633c823ac09d9ca36a45
Reviewed-on: https://go-review.googlesource.com/c/go/+/208897
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Linux 5.2 introduced a bug that can corrupt vector registers on return
from a signal if the signal stack isn't faulted in:
https://bugzilla.kernel.org/show_bug.cgi?id=205663

This CL works around this by mlocking the top page of all Go signal
stacks on the affected kernels.

Fixes #35326, #35777

Change-Id: I77c80a2baa4780827633f92f464486caa222295d
Reviewed-on: https://go-review.googlesource.com/c/go/+/209899
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Chase <drchase@google.com>

This will be used to parse the Linux kernel versions, but this code is
generic and can be tested on its own.

For #35777.

Change-Id: If1df48d07250e5855dde45bc9d57c66f777b9fb4
Reviewed-on: https://go-review.googlesource.com/c/go/+/209597
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Test set GOOS to linux and darwin without setting GOARCH. darwin is
not a valid GOOS for all architectures we test.

Fixes #35976

Change-Id: I4da2ebcbf9ad52e07bcc1632b48fcfdbc49b1289
Reviewed-on: https://go-review.googlesource.com/c/go/+/209900
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>