For #22095
Change-Id: Ie9ae84c758af99ac7daed26d0b3e3b0a47599edd
Reviewed-on: https://go-review.googlesource.com/67315
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
amd64 and 386 have rules to reduce multiplication by a positive power
of two, but a more general reduction (both for positive and negative
powers of two) is already performed by generic rules that were added
in CL 36323 to replace walkmul (see lines 166:173 in generic.rules).
The x86 and amd64 rules are never triggered during all.bash and can be
removed, reducing rules duplication.
The change also adds a few code generation tests for amd64 and 386.
Change-Id: I566d48186643bd722a4c0137fe94e513b8b20e36
Reviewed-on: https://go-review.googlesource.com/68450
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This is only to aid in human debugging, and for that reason we maintain a panic, and not return an error.
Fixes#22097
Change-Id: If72e4d1e47ec9125ca7bc97d5fe4cedb7f76ae72
Reviewed-on: https://go-review.googlesource.com/67970
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Change-Id: I34008f56c191df0edcaafc20d569bbc6184f89fc
Reviewed-on: https://go-review.googlesource.com/68470
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TestUnexportedSymbols requires dup2 that
my gcc installation does not have.
TestSignalHandlersWithNotify fails with:
undefined: syscall.SIGIO.
TestSignalHandlers fails with:
sched.h: No such file or directory.
TestExportedSymbolsWithDynamicLoad fails with:
dlfcn.h: No such file or directory.
Also add t.Helper calls to better error messages.
Updates #11058
Change-Id: I7eb514968464256b8337e45f57fcb7d7fe0e4693
Reviewed-on: https://go-review.googlesource.com/68410
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
ORETJMP doesn't need an ONAME if we just set the target method on Sym
instead of Left. Conveniently, this is where fmt.go was looking for it
anyway.
Change the iface parameter and global compiling_wrappers to bool.
Passes toolstash-check.
Change-Id: I5333f8bcb4e06bf8161808041125eb95c439aafe
Reviewed-on: https://go-review.googlesource.com/68252
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Robert Griesemer <gri@golang.org>
C_PPAUTO was matching offsets that is a multiple 8. But this
condition is dropped in CL 55610, causing unaligned offset
between 256 and 504 mistakenly matched to some classes, e.g.
C_UAUTO8K. This CL restores this condition, also fixes an
error that C_PPAUTO shouldn't match C_PSAUTO, because the
latter is not guaranteed to be multiple of 8. C_PPAUTO_8 is
unnecessary, removed.
Fixes#21992.
Change-Id: I75d5a0e5f5dc3dae335721fbec1bbcd4a3b862f2
Reviewed-on: https://go-review.googlesource.com/65730
Reviewed-by: David Chase <drchase@google.com>
Combine setcc and store of result into setcc that writes directly to memory.
Triggers 200+ times in go tool.
Fixes#21630
Change-Id: Iafa22607426f4120140c88fae4b9aecb46e0bba8
Reviewed-on: https://go-review.googlesource.com/67950
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
exit1 calls the bsdthread_terminate system call on Darwin. Currently
it passes no arguments on 386, arm, and arm64, and an exit status on
amd64. None of these are right. The signature of bsdthread_terminate
is:
int bsdthread_terminate(user_addr_t stackaddr, size_t freesize, uint32_t port, uint32_t sem);
Fix all of the Darwin exit1 implementations to call
bsdthread_terminate with 0 for all of these arguments so it doesn't
try to unmap some random memory, free some random port, or signal a
random semaphore.
This isn't a problem in practice because exit1 is never called.
However, we're about to start using exit1.
Change-Id: Idc534d196e3104e5253fc399553f21eb608693d7
Reviewed-on: https://go-review.googlesource.com/46036
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This was for cmd/cgo, and cmd/cgo isn't special anymore.
Change-Id: I71efaf553b24798b523c7102859428d36b470698
Reviewed-on: https://go-review.googlesource.com/68530
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The core dump reader wants to know the layout of this type.
No variable has this type, so it wasn't previously dumped
to DWARF output.
Change-Id: I982040b81bff202976743edc7fe53247533a9d81
Reviewed-on: https://go-review.googlesource.com/68312
Reviewed-by: Austin Clements <austin@google.com>
Currently, there is a single bit for LockOSThread, so two calls to
LockOSThread followed by one call to UnlockOSThread will unlock the
thread. There's evidence (#20458) that this is almost never what
people want or expect and it makes these APIs very hard to use
correctly or reliably.
Change this so LockOSThread/UnlockOSThread can be nested and the
calling goroutine will not be unwired until UnlockOSThread has been
called as many times as LockOSThread has. This should fix the vast
majority of incorrect uses while having no effect on the vast majority
of correct uses.
Fixes#20458.
Change-Id: I1464e5e9a0ea4208fbb83638ee9847f929a2bacb
Reviewed-on: https://go-review.googlesource.com/45752
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The primary build tools cmd/asm, cmd/compile, and cmd/link are
built during cmd/dist bootstrap and then assumed by cmd/go to
be available for any future builds.
The only tool invoked by cmd/go during a build and not in this list
is cmd/cgo; instead of being built during cmd/dist and assumed by
cmd/go, cmd/go arranges to build cmd/cgo if needed as part of
the regular build. We got here because at the time cmd/go was written,
cmd/cgo was the only build tool written in Go (the others were in C),
and so it made some sense to put cmd/dist in charge of building
the C tools and to have custom code in cmd/go to build cmd/cgo
just in time for it to be used by a particular build.
This custom code has historically been quite subtle, though, because
the build of cmd/cgo inherits whatever build flags apply to the
build that wants to use cmd/cgo. If you're not careful,
"go install -race strings" might under the wrong circumstances
also install a race-enabled cmd/cgo binary, which is unexpected
at the least.
The custom code is only going to get more problematic as we
move toward more precise analysis of whether dependencies are
up-to-date. In that case, "go build -race strings" will check to
see if there is not just a cmd/cgo already but a race-enabled
cmd/cgo, which makes no sense.
Instead of perpetuating the special case, treat cgo like all the
other build tools: build it first in cmd/dist, and then assume it is present.
This simplifies cmd/go.
Building cmd/cgo during bootstrap also allows the default
build of cmd/cgo to be built using cgo, which may be necessary
on future essentially-cgo-only systems.
Change-Id: I414e22c10c9920f4e98f97fa35ff22058c0f143d
Reviewed-on: https://go-review.googlesource.com/68338
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The loop finder doesn't return good information if it
encounters an irreducible loop. Make a start on improving
this, and set a function-level flag to indicate when there
is such a loop (and the returned information might be flaky).
Use that flag to prevent the loop rotater from getting
confused; the existing code seems to depend on artifacts
of the previous loop-finding algorithm. (There is one
irreducible loop in the go library, in "inflate.go").
Change-Id: If6e26feab38d9b009d2252d556e1470c803bde40
Reviewed-on: https://go-review.googlesource.com/42150
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Telling the truth about these will be important for
content-based staleness checks.
Change-Id: Iaed6ca6c945eb805d815156753a3e5dc48c6f0b9
Reviewed-on: https://go-review.googlesource.com/68336
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Init functions are problematic because we want cmd/link to be
able to insert an import of runtime/cgo for external linking.
For all the other systems that just means putting runtime/cgo into
the binary. The linker is not set up to generate calls to init functions,
and luckily this one can be avoided entirely.
This means people don't have to import _ "runtime/cgo" in their
iOS programs anymore. The linker's default import is now enough.
This CL also adjusts cmd/go to record the linker's default import,
now that the explicit import is gone.
Change-Id: I81d23476663e03664f90d531c24db2e4f2e6c66b
Reviewed-on: https://go-review.googlesource.com/68490
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Historically, gc optimistically parsed the left-hand side of
assignments as expressions. Later, if it discovered a ":=" assignment,
it rewrote the parsed expressions as declarations.
This failed in the presence of dot imports though, because we lost
information about whether an imported object was named via a bare
identifier "Foo" or a normal qualified "pkg.Foo".
This CL fixes the issue by specially noding the left-hand side of ":="
assignments.
Fixes#22076.
Change-Id: I18190ecdb863112e7d009e1687e6112eec559921
Reviewed-on: https://go-review.googlesource.com/66810
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This applies the amd64-specific changes from CL 42611 to the s390x P256
implementation. The s390x implementation was disabled in CL 62292 and
this CL re-enables it.
Adam Langley's commit message from CL 42611:
The optimised P-256 includes a CombinedMult function, which doesn't do
dual-scalar multiplication, but does avoid an affine conversion for
ECDSA verification.
However, it currently uses an assembly point addition function that
doesn't handle exceptional cases.
Fixes#20215.
Change-Id: I2f6b532f495e85b8903475b4f64cc32a3b2f6769
Reviewed-on: https://go-review.googlesource.com/64290
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
We're going to start building cmd/cgo as part of the bootstrap,
and with it debug/elf, so the copy here needs to work with Go 1.4.
It does except for the use of the new io.SeekStart etc constants,
so remove that use.
Change-Id: Ib7fcf46e1e9060f96d2bacaaf349c9b0df347550
Reviewed-on: https://go-review.googlesource.com/68337
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This shortens the args lists but also sets up better for
the content-based staleness changes.
While we're here, delete the now-unused Pkgpath method.
Change-Id: Ic60fa03efbc37a7c7fe9758a1cfa5dddef1a4151
Reviewed-on: https://go-review.googlesource.com/68335
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The following instructions were introduced in ARMv6, and the compiler
can do more optimization with them.
1. "MOVBS Rm@>i, Rd": rotates Rm 0/8/16/24 bits, does signed
byte extension to word, and writes the result to Rd.
2. "MOVHS Rm@>i, Rd": rotates Rm 0/8/16/24 bits, does signed
halfword extension to word, and writes the result to Rd.
3. "MOVBU Rm@>i, Rd": rotates Rm 0/8/16/24 bits, does unsigned
byte extension to word, and writes the result to Rd.
4. "MOVHU Rm@>i, Rd": rotates Rm 0/8/16/24 bits, does unsigned
half-word extension to word, and writes the result to Rd.
5. "XTAB Rm@>i, Rn, Rd": rotates Rm 0/8/16/24 bits, does signed
byte extension to word, adds Rn, and writes the result to Rd.
6. "XTAH Rm@>i, Rn, Rd": rotates Rm 0/8/16/24 bits, does signed
half-word extension to word, adds Rn, and writes the result to Rd.
7. "XTABU Rm@>i, Rn, Rd": rotates Rm 0/8/16/24 bits, does unsigned
byte extension to word, adds Rn, and writes the result to Rd.
8. "XTAHU Rm@>i, Rn, Rd": rotates Rm 0/8/16/24 bits, does unsigned
half-word extension to word, adds Rn, and writes the result to Rd.
Change-Id: I4306d7ebac93015d7e2e40d307f2c4271c03f466
Reviewed-on: https://go-review.googlesource.com/65790
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
For #22095
Change-Id: I2cb0d3e0aaf9f97952cf8dda0e99a4379e275020
Reviewed-on: https://go-review.googlesource.com/68332
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For #22095
Change-Id: I07c288208d94dabae164c2ca0a067402a8e5c2e6
Reviewed-on: https://go-review.googlesource.com/68331
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Moves type symbol name mangling out of the object reader
and into a separate pass. Requires some care, as changing
the name of a type may require dealing with duplicate
symbols for the first time.
Disables DWARF for both plugins and programs that use plugin.Open,
because type manging is currently incompatible with the go.info.*
symbol generator in cmd/link. (It relies on the symbol names to
find type information.) A future fix for this would be moving the
go.info.* generation into the compiler, with the logic we use
for generating the type.* symbols.
Fixes#19529
Change-Id: I75615f8bdda86ff9e767e536d9aa36e15c194098
Reviewed-on: https://go-review.googlesource.com/67312
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
There is no cache here yet. This CL defines ActionID, Hash, and HashFile,
which the new content-based staleness code can use. Eventually we'll
put a real cache implementation here, but it's not necessary yet.
Change-Id: Ide433cb449f4dbe658694453f348c947642df79b
Reviewed-on: https://go-review.googlesource.com/67311
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
(*sigctxt).fault() currently returns either uintptr, uint32, or uint64
depending on the platform. Make them all return uintptr.
For #10958 (but a nice change on its own).
Change-Id: I7813e779d0edcba112dd47fda776f4ce6e50e227
Reviewed-on: https://go-review.googlesource.com/68015
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Currently the linker figures out where runtime-gdb.py should be by
looking for the path to runtime/debug.go. However, debug.go contains
only a few symbols and can easily get dead-code eliminated entirely,
especially from simple binaries. When this happens, the resulting
binary lacks a reference to runtime-gdb.py, so the GDB helpers don't
get loaded.
Fix this by instead sniffing for runtime/proc.go. This contains
runtime.main and the scheduler, so it's not going anywhere.
Change-Id: Ie3380c77c840d28614fada68b8c5861625f2aff5
Reviewed-on: https://go-review.googlesource.com/68019
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
All of the callers want a *obj.LSym instead of a *types.Sym, and the
runtime type descriptors don't need Go source symbols anyway.
Passes toolstash-check.
Change-Id: I8ae4b64380fbb547857f49b42465118f41884eed
Reviewed-on: https://go-review.googlesource.com/68251
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Before CL 62530 fastrand always returned non-zero value, and one
condition in sema.go depends on this behavior.
fastrand is used to generate random weight for treap of sudog, and
it is checked against zero to verify sudog were inserted into treap or
wait queue.
Since its precision is not very important for correctness, lets just
always set its lowest bit in this place.
Updates #22047
Updates #21806
Change-Id: Iba0b56d81054e6ef9c49ffd293fc5d92a6a31e9b
Reviewed-on: https://go-review.googlesource.com/68050
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
PlainAuth originally refused to send passwords to non-TLS servers
and was documented as such.
In 2013, issue #5184 was filed objecting to the TLS requirement,
despite the fact that it is spelled out clearly in RFC 4954.
The only possibly legitimate use case raised was using PLAIN auth
for connections to localhost, and the suggested fix was to let the
server decide: if it advertises that PLAIN auth is OK, believe it.
That approach was adopted in CL 8279043 and released in Go 1.1.
Unfortunately, this is exactly wrong. The whole point of the TLS
requirement is to make sure not to send the password to the wrong
server or to a man-in-the-middle. Instead of implementing this rule,
CL 8279043 blindly trusts the server, so that if a man-in-the-middle
says "it's OK, you can send me your password," PlainAuth does.
And the documentation was not updated to reflect any of this.
This CL restores the original TLS check, as required by RFC 4954
and as promised in the documentation for PlainAuth.
It then carves out a documented exception for connections made
to localhost (defined as "localhost", "127.0.0.1", or "::1").
Change-Id: I1d3729bbd33aa2f11a03f4c000e6bb473164957b
Reviewed-on: https://go-review.googlesource.com/68170
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This can only lead to confusion.
Change-Id: Iae84c6404ab5eeb6950faa2364f97a017c67c506
Reviewed-on: https://go-review.googlesource.com/68110
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Simon Rawet <Simon@rawet.se>
This removes some of the []byte/string conversions currently
existing in the (un)marshaling methods of Int and Rat.
For Int we introduce a new function (*Int).setFromScanner() essentially
implementing the SetString method being given an io.ByteScanner instead
of a string. So we can handle the string case in (*Int).SetString with
a *strings.Reader and the []byte case in (*Int).UnmarshalText() with a
*bytes.Reader now avoiding the []byte/string conversion here.
For Rat we introduce a new function (*Rat).marshal() essentially
implementing the String method outputting []byte instead of string.
Using this new function and the same formatting rules as in
(*Rat).RatString we can implement (*Rat).MarshalText() without
the []byte/string conversion it used to have.
Change-Id: Ic5ef246c1582c428a40f214b95a16671ef0a06d9
Reviewed-on: https://go-review.googlesource.com/65950
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
It was only waiting 0.1 seconds for the two GCs it wanted.
Let it wait 1 second.
Change-Id: Ib3cdc8127cbf95694a9f173643c02529a85063af
Reviewed-on: https://go-review.googlesource.com/68151
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Before this change the ct == 0 check could never be true. Moreover the
values were not properly indirected.
Change-Id: Ice47e36e3492babc4b47d2f9099e8772be231c96
Reviewed-on: https://go-review.googlesource.com/68130
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Run-TryBot: Daniel Theophanes <kardianos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Preparation for moving the object file reader to its own package.
For #22095
Change-Id: I31fe4a10a2c465f8ea4bf548f40918807e4ec6b5
Reviewed-on: https://go-review.googlesource.com/67314
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Fix incorrect reference to string instead of byte slice.
Change-Id: I95553da32acfbcf5dde9613b07ea38408cb31ae8
Reviewed-on: https://go-review.googlesource.com/68090
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Also reduce the passed context from *Link to *sys.Arch, so fewer
data dependencies need to be wired through all the code dealing
with symbols.
For #22095
Change-Id: I50969405d6562c5152bd1a3c443b72413e9b70bc
Reviewed-on: https://go-review.googlesource.com/67313
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Update golang/go#22120
Change-Id: Ie7dbd0e7b01b116c960243a8cd3fa9fd121f317d
Reviewed-on: https://go-review.googlesource.com/68021
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
All current darwin architectures seem to take at least 100ms to dial a closed port,
and that was making the all.bash script fail.
Fixes#22062
Change-Id: Ib79c4b7a5db2373c95ce5d993cdcbee55cc0667f
Reviewed-on: https://go-review.googlesource.com/67350
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Begin passing coutbuf by as a parameter. To make the initial plumbing
pass easier, it is also a field in the standard ctxt parameter.
Consolidate the byte writing functions into the OutBuf object.
The result is less architecture-dependent initialization.
To avoid plumbing out everywhere we want to report an error, move
handling of out file deletion to an AtExit function.
For #22095
Change-Id: I0863695241562e0662ae3669666c7922b8c846f9
Reviewed-on: https://go-review.googlesource.com/67318
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For #22095
Change-Id: I9d1f0d93f8fd701a24af826dc903eea2bc235de2
Reviewed-on: https://go-review.googlesource.com/67317
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
