Trying to call a method on a nil interface is a panic in Go. For
example:

	var stringer fmt.Stringer
	println(stringer.String()) // nil pointer dereference

In https://golang.org/cl/143097 we started recovering panics encountered
during function and method calls. However, we didn't handle this case,
as text/template panics before evalCall is ever run.

In particular, reflect's MethodByName will panic if the receiver is of
interface kind and nil:

	panic: reflect: Method on nil interface value

Simply add a check for that edge case, and have Template.Execute return
a helpful error. Note that Execute shouldn't just error if the interface
contains a typed nil, since we're able to find a method to call in that
case.

Finally, add regression tests for both the nil and typed nil interface
cases.

Fixes #30143.

Change-Id: Iffb21b40e14ba5fea0fcdd179cd80d1f23cabbab
Reviewed-on: https://go-review.googlesource.com/c/161761
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

Its only use was removed in golang.org/cl/114797, committed in October
2018.

Change-Id: I6560ccfb10d7c763f6470b20c853716779c18cee
Reviewed-on: https://go-review.googlesource.com/c/158897
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

We've got away with not copying the testdata directories for the
standard library because the exec wrapper also pushes almost the
entire $GOROOT tree to the device, including testdata directories.

Similar to what the iOS exec wrapper does.

Change-Id: I91ef63ef84a658fc8843002890132c64b7c1d20e
Reviewed-on: https://go-review.googlesource.com/c/163626
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Android emulator builders are soon to join the trybot set. To avoid
flaky runs, work around a longstanding adb bug where concurrent adb
commands sometimes fail.

I haven't seen the problem on actual devices until recently. It seems
that the recently added "adb wait-for-device" can introduce flakyness
with errors such as:

adb: error: failed to get feature set: protocol fault (couldn't read status): Connection reset by peer

Instead of working around that, give up and serialize use of adb
everywhere.

Fixes #23795
Updates #23824

Change-Id: If347c9981fa32ff8a1e14b7454f122ef682450a6
Reviewed-on: https://go-review.googlesource.com/c/163625Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

To run the standard library tests on Android, the androidtest.bash
script copies GOROOT to the device. Move that logic to the android
exec wrapper, thereby making androidtest.bash obsolete.

Apart from making Android less special, the sharded builder
infrastructure should now be able to run (emulated) Android builders
and trybots without special treatment.

Updates #23824

Change-Id: I41591fea9a15b38c6dcf84046ea57f1e9165eaa5
Reviewed-on: https://go-review.googlesource.com/c/163619
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #29423

Change-Id: I376d0776c3810c2273d1ea234ebe681d5fd2ae64
Reviewed-on: https://go-review.googlesource.com/c/163623
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>

The androidtest.bash script encodes the additional steps to build
Go and run tests on Android. In order to add sharded builders and
trybots, Android needs to fit into the usual make.bash + cmd/dist test
pattern.

This change moves building the exec wrapper into cmd/dist bootstrap.

Do the same for iOS while we're here.

Updates #23824

Change-Id: I58a1b0679c3a6c92fdc7fff464b469641f1fee74
Reviewed-on: https://go-review.googlesource.com/c/163618
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Use ReverseBytes32 and ReverseBytes64 to speed up these functions.
The byte reversal functions are intrinsics on most platforms and
generally compile to a single instruction.

name       old time/op  new time/op  delta
Reverse32  2.41ns ± 1%  1.94ns ± 3%  -19.60%  (p=0.000 n=20+19)
Reverse64  3.85ns ± 1%  2.56ns ± 1%  -33.32%  (p=0.000 n=17+19)

Change-Id: I160bf59a0c7bd5db94114803ec5a59fae448f096
Reviewed-on: https://go-review.googlesource.com/c/159358
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

The old code looks suspicious and is fragile.
It would fail if error messages were not totally the same.
Swapped the arguments order to fix that.

Change-Id: Id5df7242fb9224d0090245286ef8986ebb15e921
Reviewed-on: https://go-review.googlesource.com/c/161157
Run-TryBot: Iskander Sharipov <quasilyte@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

If we're accessing a field on a nil struct pointer, and that field is
present in the type, we should print a "nil pointer evaluating X.Y" error
instead of the broader "can't evaluate field Y in X". The latter error
should still be used for the cases where the field is simply missing.

While at it, remove the isNil checks in the struct and map cases. The
indirect func will only return a true isNil when returning a pointer or
interface reflect.Value, so it's impossible for either of these checks
to be useful.

Finally, extend the test suite to test a handful of these edge cases,
including the one shown in the original issue.

Fixes #29137.

Change-Id: I53408ced8a7b53807a0a8461b6baef1cd01d25ae
Reviewed-on: https://go-review.googlesource.com/c/153341
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

I forgot how to pull up the ssa debug options help, so instead of
writing -d=ssa/help, I just wrote -d=ssa/. Much to my amusement, the
compiler just crashed, as shown below. Fix that.

	panic: runtime error: index out of range

	goroutine 1 [running]:
	cmd/compile/internal/ssa.PhaseOption(0x7ffc375d2b70, 0x0, 0xdbff91, 0x5, 0x1, 0x0, 0x0, 0x1, 0x1)
	    /home/mvdan/tip/src/cmd/compile/internal/ssa/compile.go:327 +0x1876
	cmd/compile/internal/gc.Main(0xde7bd8)
	    /home/mvdan/tip/src/cmd/compile/internal/gc/main.go:411 +0x41d0
	main.main()
	    /home/mvdan/tip/src/cmd/compile/main.go:51 +0xab

Change-Id: Ia2ad394382ddf8f4498b16b5cfb49be0317fc1aa
Reviewed-on: https://go-review.googlesource.com/c/154421
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Go 1.12 is released, but it's currently not listed in the
https://golang.org/project page.

Change-Id: Ib5820f74245e4c986014c64eb40fa2911473e64b
Reviewed-on: https://go-review.googlesource.com/c/163837Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The example for Nanoseconds() currently reads:

  ns, _ := time.ParseDuration("1000ns")
  fmt.Printf("one microsecond has %d nanoseconds.", ns.Nanoseconds())

which is not terribly interesting: it seems obvious that parsing
"1000ns" and then calling Nanoseconds() will print 1000. The mention
of microseconds in the text suggests that the author's intention was,
instead, to write something like this:

  u, _ := time.ParseDuration("1us")

i.e. build a time value by parsing 1 microsecond, and then print the
value in nanoseconds. Change the example to do this.

Change-Id: I4ddb123f0935a12cda3b5d6f1ca919bfcd6383d6
Reviewed-on: https://go-review.googlesource.com/c/163622Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

I hope that this will fix the tests on iOS, but 'gomote create' isn't
giving me an instance I can test with. (Please patch and test before
approving.)

Updates #15919
Updates #30228

Change-Id: I1b7cd30d5b127a1ad3243b329fa005d229f69a24
Reviewed-on: https://go-review.googlesource.com/c/163726
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Elias Naur <mail@eliasnaur.com>

This CL updates text/template's scanner to accept the
new number syntaxes:

 - Hexadecimal floating-point values.
 - Digit-separating underscores.
 - Leading 0b and 0o prefixes.

See golang.org/design/19308-number-literals for background.

For #12711.
For #19308.
For #28493.
For #29008.

Change-Id: I68c16ea35c3f506701063781388de72bafee6b8d
Reviewed-on: https://go-review.googlesource.com/c/160248Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

This CL updates fmt's scanner to accept the new number syntaxes:

 - Hexadecimal floating-point values.
 - Digit-separating underscores.
 - Leading 0b and 0o prefixes.

See golang.org/design/19308-number-literals for background.

For #12711.
For #19308.
For #28493.
For #29008.

Change-Id: I5582af5c94059c781e6cf4e862441d3df3006adf
Reviewed-on: https://go-review.googlesource.com/c/160247Reviewed-by: Robert Griesemer <gri@golang.org>

This CL modifies fmt's printer to implement %#b and %O
to emit leading 0b and 0o prefixes on binary and octal.
(%#o is already taken and emits "0377"; %O emits "0o377".)

See golang.org/design/19308-number-literals for background.

For #19308.
For #12711.
Vet update is #29986.

Change-Id: I7c38a4484c48a03abe9f6d45c7d981c7c314f583
Reviewed-on: https://go-review.googlesource.com/c/160246Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

This CL modifies fmt's printer to implement %x and %X
for formatting floating-point data (floats and complexes)
in standard hexadecimal notation.

See golang.org/design/19308-number-literals for background.

For #29008.
Vet update is #29986.

Change-Id: If2842a11631bc393a1ebcf6914ed07658652af5a
Reviewed-on: https://go-review.googlesource.com/c/160245Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Updates #30241

Change-Id: I543d8914faf810835d3327baa3c84b3dff124156
Reviewed-on: https://go-review.googlesource.com/c/163519Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates #30228

Change-Id: I41bbedf15fa51242f69a3b1ecafd0d3191271799
Reviewed-on: https://go-review.googlesource.com/c/163518Reviewed-by: Jay Conrod <jayconrod@google.com>

These source files fail to build with 'go test ./...'.
Move them into testdata so that only test.bash will see them.

Updates #30228

Change-Id: I3673f3cb64b0c128a2bca5fee7679b672fe90770
Reviewed-on: https://go-review.googlesource.com/c/163212Reviewed-by: Ian Lance Taylor <iant@golang.org>

Add _test.go files in the individal directories to invoke 'go build'
with appropriate arguments.

Move the test driver out of cmd/dist so that it's easier to invoke the
test separately (using 'go test .').

Updates #30228
Updates #28387

Change-Id: Ibc4a024a52c12a274058298b41cc90709f7f56c8
Reviewed-on: https://go-review.googlesource.com/c/163420Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I845375d2b3824211b80885228ba5b45503cba1a6
Reviewed-on: https://go-review.googlesource.com/c/163722Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ib6a0f5c35b1efc3f3c8e7ca2a5c4f35bf8bf5e5d
Reviewed-on: https://go-review.googlesource.com/c/163720Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Using go get prevents the failure case of when the
user doesn't have the repo on their machine.

Change-Id: I9c1174087728b5b06b578b0d52df6eeb7e8c7a3c
Reviewed-on: https://go-review.googlesource.com/c/163718Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

A recent change to fix stacktraces for inlined functions
introduced a regression on ppc64le when compiling position
independent code. That happened because ginsnop2 was called for
the purpose of inserting a NOP to identify the location of
the inlined function, when ginsnop should have been used.
ginsnop2 is intended to be used before deferreturn to ensure
r2 is properly restored when compiling position independent code.
In some cases the location where r2 is loaded from might not be
initialized. If that happens and r2 is used to generate an address,
the result is likely a SEGV.

This fixes that problem.

Fixes #30283

Change-Id: If70ef27fc65ef31969712422306ac3a57adbd5b6
Reviewed-on: https://go-review.googlesource.com/c/163337Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates #23824

Change-Id: I5472a05eb2cf571ccc84c76c6f592bf4dd2e3cb4
Reviewed-on: https://go-review.googlesource.com/c/163621
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This reverts commit 27b9571d.

Reason for revert: broke the multi-device Android builder. And the wait logic is moving to the exec wrapper anyway.

Change-Id: I3e429106bbe70b3a12286f8f229a2b558279eec4
Reviewed-on: https://go-review.googlesource.com/c/163620
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates #30228

Change-Id: Ie972694254d2195ca9760ea7ffb6073e01c52488
Reviewed-on: https://go-review.googlesource.com/c/163422
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Updates #30228

Change-Id: I4d213c6fe68c47ccb877f13b55128e035f76a26b
Reviewed-on: https://go-review.googlesource.com/c/163421
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates #30228
Updates #28387

Change-Id: Iad7d960b70221f90ccc2372bb1d4d41cec3926e4
Reviewed-on: https://go-review.googlesource.com/c/163214
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This change preserves the ability to test misc/cgo/test in GOPATH
mode, at the cost of indirection through a 'go test' subprocess.

Updates #30228

Change-Id: I08de855e62278d30fa622b2f7478e43dd2ab0e96
Reviewed-on: https://go-review.googlesource.com/c/163418
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

info.Name returns a name relative to the directory, so we need to
prefix that directory in the Stat call.

(This was missed in CL 141097 due to the fact that the test only
happened to check symlinks in the current directory.)

This allows the misc/ tests to work in module mode on platforms that
support symlinks.

Updates #30228
Updates #28107

Change-Id: Ie31836382df0cbd7d203b7a8b637c4743d68b6f3
Reviewed-on: https://go-review.googlesource.com/c/163517
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

If we run 'go test ./...' in the misc module, we don't want to see
errors for these standalone files.

We could instead add +ignore tags to each file individually, but this
is exactly what a testdata directory is for.

Updates #30228

Change-Id: I7047ad888dd6aff701f5982d58b6a79f6a487c58
Reviewed-on: https://go-review.googlesource.com/c/163417
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Updates #30228

Change-Id: Ie9dca7c64be8dff729be98cb6190236287afd23e
Reviewed-on: https://go-review.googlesource.com/c/163213
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Updates #30228

Change-Id: I5cc739eb9fdfb648ec45e350d43d4cb02e450553
Reviewed-on: https://go-review.googlesource.com/c/163211
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Updates #30228

Change-Id: I830e3c83416b2e5744f30d1a903a74c50462716b
Reviewed-on: https://go-review.googlesource.com/c/163210
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Updates #23824

Change-Id: I265e3f40192a0a4bf54f608d9408ba0cfef2b69c
Reviewed-on: https://go-review.googlesource.com/c/163457
Run-TryBot: Elias Naur <mail@eliasnaur.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates #30228

Change-Id: I84bc705591bdb3da0106404b24353251939355b8
Reviewed-on: https://go-review.googlesource.com/c/163209Reviewed-by: Jay Conrod <jayconrod@google.com>

Nothing in Go can truly guarantee a key will be gone from memory (see
#21865), so remove that claim. That makes Reset useless, because
unlike most Reset methods it doesn't restore the original value state,
so deprecate it.

Change-Id: I6bb0f7f94c7e6dd4c5ac19761bc8e5df1f9ec618
Reviewed-on: https://go-review.googlesource.com/c/162297Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>