Also add a -testwork flag to facilitate debugging the test itself.

Three of the tests of this package invoked 'go install -i
-buildmode=c-archive' in order to generate an archive as well as
multiple C header files.

Unfortunately, the behavior of the '-i' flag is inappropriately broad
for this use-case: it not only generates the library and header files
(as desired), but also attempts to install a number of (unnecessary)
archive files for transitive dependencies to
GOROOT/pkg/$GOOS_$GOARCH_shared, which may not be writable — for
example, if GOROOT is owned by the root user but the test is being run
by a non-root user.

Instead, for now we generate the header files for transitive dependencies
separately by running 'go tool cgo -exportheader'.

In the future, we should consider how to improve the ergonomics for
generating transitive header files without coupling that to
unnecessary library installation.

Updates #28387
Updates #30316
Updates #35715

Change-Id: I3d483f84e22058561efe740aa4885fc3f26137b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/208117
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The profile proto message builder maintains a location entry cache
that maps a location (possibly involving multiple user frames
that represent inlined function calls) to the location id. We have
been using the first pc of the inlined call sequence as the key of
the cached location entry assuming that, for a given pc, the sequence
of frames representing the inlined call stack is deterministic and
stable. Then, when analyzing the new stack trace, we expected the
exact number of pcs to be present in the captured stack trace upon
the cache hit.

This assumption does not hold, however, in the presence of the stack
trace truncation in the runtime during profiling, and also with the
potential bugs in runtime.

A better fix is to use all the pcs of the inlined call sequece as
the key instead of the first pc. But that is a bigger code change.
This CL avoids the crash assuming the trace was truncated.

Fixes #35538

Change-Id: I8c6bae98bc8b178ee51523c7316f56b1cce6df16
Reviewed-on: https://go-review.googlesource.com/c/go/+/207609
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: Ie3495a51ac2021a55e7c1ee43a66d07a5bf2757a
GitHub-Last-Rev: b6a6bab3ab840b361021b25cac37eb6891c0fe4b
GitHub-Pull-Request: golang/go#35709
Reviewed-on: https://go-review.googlesource.com/c/go/+/207853Reviewed-by: Ian Lance Taylor <iant@golang.org>

The fix for #35652 did not guarantee that it was using a non-empty
src position to replace an empty one.  The new code checks again
and falls back to a more certain position.  (The input in question
compiles to a single empty infinite loop, and none of the actual instructions
had any source position at all.  That is a bug, but given the pathology
of this input, not one worth dealing with this late in the release cycle,
if ever.)

Literally:

00000 (5) TEXT "".f(SB), ABIInternal
00001 (5) PCDATA $0, $-2
00002 (5) PCDATA $1, $-2
00003 (5) FUNCDATA $0, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
00004 (5) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
00005 (5) FUNCDATA $2, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
b2
00006 (?) XCHGL AX, AX
b6
00007 (+1048575) JMP 6
00008 (?) END

TODO: Add runtime.InfiniteLoop(), replace infinite loops with a call to
that, and use an eco-friendly runtime.gopark instead.  (This was Cherry's
excellent idea.)

Updates #35652
Fixes #35695

Change-Id: I4b9a841142ee4df0f6b10863cfa0721a7e13b437
Reviewed-on: https://go-review.googlesource.com/c/go/+/207964
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Fixes #35750

Change-Id: I65d38cfc5ddd66131777e104c269cc3559b2471d
GitHub-Last-Rev: 953fdfd49b2be665be43f8148d2a6180dae3b91c
GitHub-Pull-Request: golang/go#35751
Reviewed-on: https://go-review.googlesource.com/c/go/+/208318Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Ampersand and equal are not dangerous in a JS/JSString context
but they might cause issues if interpolated in HTML attributes.

This change makes it harder to introduce XSS by misusing
escaping.

Thanks to t1ddl3r <t1ddl3r@gmail.com> for reporting this common
misuse scenario.

Fixes #35665

Change-Id: Ice6416477bba4cb2ba2fe2cfdc20e027957255c0
Reviewed-on: https://go-review.googlesource.com/c/go/+/207637Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Mike Samuel <mikesamuel@gmail.com>
Reviewed-by: Andrew Bonventre <andybons@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

NPN was removed in CL 174329.

Change-Id: Ic63ad53e7e24872e28673d590727e0300f435619
Reviewed-on: https://go-review.googlesource.com/c/go/+/208224
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Previously, we just reported an error for "all". Now we report an
error for any pattern that matches modules in the build list. The
build list can only contain the module "command-line-arguments", so
these patterns are not meaningful.

Fixes #35728

Change-Id: Ibc736491ec9164588f9657c09d1b9683b33cf1de
Reviewed-on: https://go-review.googlesource.com/c/go/+/208222
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

In TestAsyncPreempt, the function being tested for preemption,
although still asynchronously preemptible, may have only samll
ranges of PCs that are preemtible. In an unlucky run, it may
take quite a while to have a signal that lands on a preemptible
instruction. The test case is kind of an extreme. Relax it to
make it more preemptible.

In the original version, the first closure has more work to do,
and it is not a leaf function, and the second test case is a
frameless leaf function. In the current version, the first one
is also a frameless leaf function (the atomic is intrinsified).
Add some calls to it. It is still not preemptible without async
preemption.

Fixes #35608.

Change-Id: Ia4f857f2afc55501c6568d7507b517e3b4db191c
Reviewed-on: https://go-review.googlesource.com/c/go/+/208221
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #35735

Change-Id: I4618ffcd1bcf9a7506468b9a1443bc4a2f7f3138
GitHub-Last-Rev: edaf780d3d8b4e01f3dd6750275ff50a39eb2113
GitHub-Pull-Request: golang/go#35736
Reviewed-on: https://go-review.googlesource.com/c/go/+/208297Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Starting with macOS 10.15 (Catalina), Apple now requires all software
distributed outside of the App Store to be notarized. Any binaries we
distribute must abide by a strict set of requirements like code-signing
and having a minimum target SDK of 10.9 (amongst others).

Apple’s notarization service will recursively inspect archives looking to
find notarization candidate binaries. If it finds a binary that does not
meet the requirements or is unable to decompress an archive, it will
reject the entire distribution. From cursory testing, it seems that the
service uses content sniffing to determine file types, so changing
the file extension will not work.

There are some binaries and archives included in our distribution that
are being detected by Apple’s service as potential candidates for
notarization or decompression. As these are files used by tests and some
are intentionally invalid, we don’t intend to ever make them compliant.

As a workaround for this, we base64-encode any binaries or archives that
Apple’s notarization service issues a warning for, as these warnings will
become errors in January 2020.

Updates #34986

Change-Id: I106fbb6227b61eb221755568f047ee11103c1680
Reviewed-on: https://go-review.googlesource.com/c/go/+/208118
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

One of the 'go build' commands executed by this test passed the '-i'
flag, which caused the 'go' command to attempt to install transitive
standard-library dependencies to GOROOT/pkg/$GOOS_$GOARCH_dynlink.

That failed if GOROOT/pkg was not writable (for example, if GOROOT was
owned by the root user, but the user running the test was not root).

As far as I can tell the '-i' flag is not necessary in this test.
Prior to the introduction of the build cache it may have been an
optimization, but now that the build cache is required the '-i' flag
only adds extra work.

Updates #30316

Change-Id: Ib60080a008c1941aa92b5bdd5a194d89fd6202aa
Reviewed-on: https://go-review.googlesource.com/c/go/+/208120
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The bash script that drives this test needs to know whether the
fortran compiler works, but it doesn't actually care about the
generated binary. Write that binary to /dev/null.

Updates #28387
Updates #30316

Change-Id: I4f86da1aeb939fc205f467511fc69235a6a9af26
Reviewed-on: https://go-review.googlesource.com/c/go/+/208124
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Reworking the comments in path to call out how leading
empty elements are treated. Also updating filepath.Join
since it shared much of the wording from path.Join.

Updates #35655

Change-Id: I5b15c5d36e9d19831ed39e6bcc7f2fd6c1330033
Reviewed-on: https://go-review.googlesource.com/c/go/+/207797Reviewed-by: Rob Pike <r@golang.org>

An application that wants to reject non-canonical encodings is likely to
care about other sources of malleability.

Change-Id: I1d3a5b281d2631ca78df3f89b957a02687a534d8
Reviewed-on: https://go-review.googlesource.com/c/go/+/188858Reviewed-by: Katie Hockman <katie@golang.org>

This implements preemptM on Windows using SuspendThead and
ResumeThread.

Unlike on POSIX platforms, preemptM on Windows happens synchronously.
This means we need a make a few other tweaks to suspendG:

1. We need to CAS the G back to _Grunning before doing the preemptM,
   or there's a good chance we'll just catch the G spinning on its
   status in the runtime, which won't be preemptible.

2. We need to rate-limit preemptM attempts. Otherwise, if the first
   attempt catches the G at a non-preemptible point, the busy loop in
   suspendG may hammer it so hard that it never makes it past that
   non-preemptible point.

Updates #10958, #24543.

Change-Id: Ie53b098811096f7e45d864afd292dc9e999ce226
Reviewed-on: https://go-review.googlesource.com/c/go/+/204340
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

On Windows, there is currently a race between unminit closing the
thread's handle and profileloop1 suspending the thread using its
handle. If another handle reuses the same handle value, this can lead
to unpredictable results.

To fix this, we protect the thread handle with a lock and duplicate it
under this lock in profileloop1 before using it.

This is going to become a much bigger problem with non-cooperative
preemption (#10958, #24543), which uses the same basic mechanism as
profileloop1.

Change-Id: I9d62b83051df8c03f3363344438e37781a69ce16
Reviewed-on: https://go-review.googlesource.com/c/go/+/207779
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

This field is only used on Windows.

Change-Id: I12d4df09261f8e7ad54c2abd7beda669af28c8e7
Reviewed-on: https://go-review.googlesource.com/c/go/+/207778
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

Since the new page allocator, AIX's GDB has trouble running Go programs.
It does work but it can be really slow. Therefore, they are disable when
tests are run with -short.

Updates: #35710

Change-Id: Ibfc4bd2cd9714268f1fe172aaf32a73612e262d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/207919
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ia65bac00fe8600f50620ce0583455eb33f06ff95
Reviewed-on: https://go-review.googlesource.com/c/go/+/207918
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>

Fixes #35703

Change-Id: I476efad38897cae93f298af86784bbc2cc2449a3
Reviewed-on: https://go-review.googlesource.com/c/go/+/208037
Run-TryBot: Baokun Lee <nototon@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Updates #33637

Change-Id: Ieb8fce1b9c44f630cddc5ff6d19daa17185867e1
Reviewed-on: https://go-review.googlesource.com/c/go/+/206618
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>

Updates #33637

Change-Id: I3a0d05551d5a680febf742b912a5a6e5af753a6e
Reviewed-on: https://go-review.googlesource.com/c/go/+/206617
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>

In CL 207962, I removed a seemingly-redundant -i flag. As it turns
out, the -i flag has *two* meanings: “install dependencies”, and “do
not actually run the test”. Without the flag, we omit the former
behavior, but add the latter.

We're about to run specific tests from these binaries on the very next
line, so don't preemptively run all of the tests.

Updates #30316

Change-Id: Ie3d8a37dc5f6bd98c232b308b0a6a165b5d82f7c
Reviewed-on: https://go-review.googlesource.com/c/go/+/207966
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

TestInstalls was already mostly redundant with
TestInstallInto{GOPATH,GOBIN}, except for one additional check for the
install location of cmd/fix.

We can't assume that GOROOT is writable in general, so we also can't
assume that the test will be able to reinstall cmd/fix at run time.
Moreover, other processes running in parallel may expect to invoke
cmd/fix themselves, so this test temporarily removing it could induce
systemwide flakes.

We could carefully construct a parallel GOROOT and install cmd/fix
into it, but we can get *almost* as much coverage — at a much lower
cost — by checking the output of 'go list' instead of actually
rebuilding and reinstalling the binary.

Updates #28387
Updates #30316

Change-Id: Id49f44a68b0c52dfabb84c665f63c4e7db58dd49
Reviewed-on: https://go-review.googlesource.com/c/go/+/207965
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Update gccgoPkgpathToSymbolNew() to bring it into conformance
with the way that gccgo now handles packagepaths with embedded
dots (see CL 200838). See also https://gcc.gnu.org/PR61880, a
related bug.

Updates #35623.

Change-Id: I32f064320b9af387fc17771530c745a9e3003c20
Reviewed-on: https://go-review.googlesource.com/c/go/+/207957
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

These terms will be defined throughout the document, and more terms
will be added. After drafting a few sections, it's clear that a
glossary will be useful. There are enough terms that it would be
overwhelming at the beginning.

Also, add anchors for each heading and add a couple more headings.

Updates #33637

Change-Id: I0017064f0b1e5e656dd280018ca0379484345df1
Reviewed-on: https://go-review.googlesource.com/c/go/+/206478
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>

The whole point of copying these files is so that we can modify them.

Updates #30316

Change-Id: Iaba7ddec5159078f2c3d3451cbab363365b15c9d
Reviewed-on: https://go-review.googlesource.com/c/go/+/207963
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

At one point (before GOCACHE), the '-i' flag meant, effectively,
“save the intermediate results of this command to make
future commands faster”.

However, now that we require GOCACHE to be enabled everywhere, '-i' no
longer has that meaning: the intermediate results are already saved in
GOCACHE, so the -i flag merely adds extra work (copying or linking
things from GOCACHE into pkg), and also adds additional failure modes
resulting from that extra work (particularly when 'pkg' is read-only).

Since the flag now causes more harm than good, omit it.

Updates #30316

Change-Id: I295b6c0fc460dfc11ffa2a964cbb2a40f2935edc
Reviewed-on: https://go-review.googlesource.com/c/go/+/207962
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I71fc3016106db733b888f3daccc00b493abe39b2
Reviewed-on: https://go-review.googlesource.com/c/go/+/207840Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates #28387
Updates #30316

Change-Id: I31e04c89f2cc226f9b5110f14c8b80a18e937efb
Reviewed-on: https://go-review.googlesource.com/c/go/+/207960
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

This test runs 'go test -race -i runtime/race' and checks that it did
not overwrite cmd/cgo.

If GOROOT/pkg is read-only and GOROOT/pkg/$GOOS_$GOARCH_race is not
already populated, as are the conditions if the Go toolchain was
installed from source as root using 'make.bash', then 'go test -race
-i' itself will fail because it cannot install packages to GOROOT/pkg.

However, such a failure is not relevant to the test: even if 'go test
-race -i' fails, we can still verify that it did not incidentally
overwrite cmd/cgo.

Updates #28387
Updates #30316

Change-Id: Iff2f75a0aeb4c926290ac3062c83695604522078
Reviewed-on: https://go-review.googlesource.com/c/go/+/207959
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Updates #28387
Updates #30316

Change-Id: I48c6dd8619ea9602e9617ce11dfa05f1c70a485d
Reviewed-on: https://go-review.googlesource.com/c/go/+/207958Reviewed-by: Jay Conrod <jayconrod@google.com>

The darwin-arm64-correlium builder was failing the test consistently
at the old values. Give the ticks more time to let the test pass.

Updates #35692

Change-Id: Ibc636cd4db2595c82f4e8c6c822c3df4c2b7e0a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/207839
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates #6239
Updates #27707

Change-Id: I65e6471829c9de4677d3ac78ef6cd7aa0a1fc4cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/171884Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

Handle immediates larger than 12-bits by rewriting as an LUI instruction with
the high bits, followed by the original instruction with the low bits.

Based on the riscv-go port.

Updates #27532

Change-Id: I8ed6d6e6db06fb8a27f3ab75f467ec2b7ff1f075
Reviewed-on: https://go-review.googlesource.com/c/go/+/204626Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Based on the riscv-go port.

Updates #27532

Change-Id: I478254306441c253d3a2c09c10932ad1ac0be3c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/204625Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Dan Scales pointed out a theoretical deadlock in the runtime.

The timer code runs timer functions while holding the timers lock for a P.
The scavenger queues up a timer function that calls wakeScavenger,
which acquires the scavenger lock.

The scavengeSleep function acquires the scavenger lock,
then calls resetTimer which can call addInitializedTimer
which acquires the timers lock for the current P.

So there is a potential deadlock, in that the scavenger lock and
the timers lock for some P may both be acquired in different order.
It's not clear to me whether this deadlock can ever actually occur.

Issue 35532 describes another possible deadlock.

The pollSetDeadline function acquires pd.lock for some poll descriptor,
and in some cases calls resettimer which can in some cases acquire
the timers lock for the current P.

The timer code runs timer functions while holding the timers lock for a P.
The timer function for poll descriptors winds up in netpolldeadlineimpl
which acquires pd.lock.

So again there is a potential deadlock, in that the pd lock for some
poll descriptor and the timers lock for some P may both be acquired in
different order. I think this can happen if we change the deadline
for a network connection exactly as the former deadline expires.

Looking at the code, I don't see any reason why we have to hold
the timers lock while running a timer function.
This CL implements that change.

Updates #6239
Updates #27707
Fixes #35532

Change-Id: I17792f5a0120e01ea07cf1b2de8434d5c10704dd
Reviewed-on: https://go-review.googlesource.com/c/go/+/207348
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

Take the opportunity of deflaking to make it take less time to run.

Updates #35537

Change-Id: I91ca8094fbe18fbfcd34dfda98da1592c9c82943
Reviewed-on: https://go-review.googlesource.com/c/go/+/207403
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This will help to detect regressions of #28387 when running
'go test cmd/go' in a writable GOROOT.

Updates #28387
Updates #30316

Change-Id: I551e044111535404688b1a76e63163dfcb41bb5c
Reviewed-on: https://go-review.googlesource.com/c/go/+/207701
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>