Type parameter resolution is a bit tricky: type parameters are in the
function scope, but unlike ordinary parameters may reference eachother.
When resolving the function scope, we must be careful about the order in
which objects are resolved and declared.
Using ordering allows us to avoid passing around temporary scopes for
field declarations.
Add a bunch of tests for this behavior, and skip "_" in resolution tests
as it just adds noise.
For #45221
Change-Id: Id080cddce3fd76396bf86ba5aba856aedf64a458
Reviewed-on: https://go-review.googlesource.com/c/go/+/304456
Trust: Robert Findley <rfindley@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
The overview comments discuss readying goroutines, which is the most
common source of work, but timers and idle-priority GC work also require
the same synchronization w.r.t. spinning Ms.
This CL should have no functional changes.
For #43997
Updates #44313
Change-Id: I7910a7f93764dde07c3ed63666277eb832bf8299
Reviewed-on: https://go-review.googlesource.com/c/go/+/307912
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Here tryWakeP can't already be true, so there is no need to combine the
values.
This CL should have no functional changes.
For #43997.
For #44313.
Change-Id: I640c7bb88a5f70c8d22f89f0b5b146b3f60c0136
Reviewed-on: https://go-review.googlesource.com/c/go/+/307911
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
findrunnable has a couple places where delta is recomputed from a new
pollUntil value. This proves to be a pain in refactoring, as it is easy
to forget to do properly.
Move computation of delta closer to its use, where it is more logical
anyways.
This CL should have no functional changes.
For #43997.
For #44313.
Change-Id: I89980fd7f40f8a4c56c7540cae03ff99e12e1422
Reviewed-on: https://go-review.googlesource.com/c/go/+/307910
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
There are stack slots that are kept live for defers, which are
tracked separately. Don't clobber them.
Change-Id: Ib558345758b5a4fd89c7ff8a3fe08087059add21
Reviewed-on: https://go-review.googlesource.com/c/go/+/310329
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
In makeFuncStub and methodValueCall, it stores ctxt (DX) as an
argument of moveMakeFuncArgPtrs, and assumes it does not change
by the call. This is not guaranteed, and it does happen if
-clobberdead compiler flag is used. Store it somewhere else and
reload after the call.
Change-Id: I9307e3cf94db4b38305ab35494088386dfcbaae8
Reviewed-on: https://go-review.googlesource.com/c/go/+/310409
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
former code only spilled those parameters mentioned in code
AT THE REGISTER LEVEL, this caused problems with liveness
sometimes (which worked on whole variables including
aggregates).
Updates #40724.
Change-Id: Ib9fdc50d95d1d2b1f1e405dd370540e88582ac71
Reviewed-on: https://go-review.googlesource.com/c/go/+/310690
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
There was a race condition that could lead to child.serveRequest
removing the request ID before child.handleRequest had read the empty
FCGI_STDIN message that indicates end-of-stream which in turn could
lead to child.serveRequest blocking while trying to consume the
request body.
Now, we remove the request ID from within child.handleRequest after
the end of stdin has been detected, eliminating the race condition.
Since there are no more concurrent modifications/accesses
to child.requests, we remove the accompanying sync.Mutex.
Change-Id: I80c68e65904a988dfa9e3cceec1829496628ff34
GitHub-Last-Rev: b3976111ae
GitHub-Pull-Request: golang/go#42840
Reviewed-on: https://go-review.googlesource.com/c/go/+/273366
Trust: Damien Neil <dneil@google.com>
Trust: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Simplified both tests significantly by removing logic for writing
the client/server side messages. The flake was likely because of a
race between the closing of the local pipe from inside the test
and closing of the pipe from within the handshakeContext goroutine.
Wait to close the local pipe in the test until after the test
has finished running.
Fixes#45106Fixes#45299
Change-Id: If7ca75aeff7df70cda03c934fa9d8513276d465d
Reviewed-on: https://go-review.googlesource.com/c/go/+/305250
Trust: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Trust: Katie Hockman <katie@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
The build.Default context really needs to accurately describe
the default build context. The goexperiment tags being a special
case in the go command violates that rule and is the root cause
of the various try-bot failures blocking the enabling of regabi.
(The cleanups I made in golang.org/x/tools were long overdue
but are not strictly necessary for making regabi work; this CL is.)
Having moved the GOEXPERIMENT parsing into internal/buildcfg,
go/build can now use it to set up build.Default, in the new field
ToolTags, meant to hold toolchain-determined tags (for now,
just the experiments). And at the same time we can remove the
duplication of GOOS and GOARCH defaults.
And then once build.Default is set up accurately, the special case
code in cmd/go itself can be removed, and the special case code
in test/run.go is at least a bit less special.
Change-Id: Ib7394e10aa018e492cb9a83fb8fb9a5011a8c25b
Reviewed-on: https://go-review.googlesource.com/c/go/+/310732
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Austin Clements <austin@google.com>
The go/build package needs access to this configuration,
so move it into a new package available to the standard library.
Change-Id: I868a94148b52350c76116451f4ad9191246adcff
Reviewed-on: https://go-review.googlesource.com/c/go/+/310731
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
For #36460
Change-Id: I50c7018a6841bba1a8c6f8f8eca150df1f685526
Reviewed-on: https://go-review.googlesource.com/c/go/+/310789
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
mainPackagesOnly now includes non-main packages matched by literal
arguments in the returned slice, since their errors must be reported.
GoFilesPackages attaches the same error to its package if
opts.MainOnly is true. This changes the error output of 'go run'
slightly, but it seems like an imporovement.
For #42088
Change-Id: I8f2942470383af5d4c9763022bc94338f5314b07
Reviewed-on: https://go-review.googlesource.com/c/go/+/310829
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
The xcoff writer has several "ldr.SymVersion(s) != 0" checks. The
intent of these is to check for file-local (or static) symbols. Prior
to the introduction of symbol ABIs, this was indeed equivalent since
only file-local symbols has non-zero versions, but ABIs also use the
symbol version space. This still happened to work until much more
recently because we were only ever cgo-exporting version 0 symbols,
but CL 309341 changed this, causing these checks to fail on symbols
that were okay to export.
Replace these checks with ldr.IsFileLocal(s).
This should fix the AIX builder.
(Originally based on CL 309772.)
Fixes#45553.
Updates #40724.
Change-Id: I0a3a7f621ad8f9fe078d34e667286275257691ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/310729
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Currently, when we about to emit code that sets the function
results and returns, it emits a VarDef. But in some cases, the
result node is actually live and holding useful data. VarDef
means that we are about to (re)initialize it so all previous
data are dead, but that is not true. Don't insert that.
Also don't add VarDef for register results. We are not going to
store anything (currently it doesn't cause problem, just
unnecessary).
Change-Id: I9dd3b70b4a3f5035af028b143fde8fafa2f11fa0
Reviewed-on: https://go-review.googlesource.com/c/go/+/310589
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
'go run' can now build a command at a specific version in module-aware
mode, ignoring the go.mod file in the current directory if there is one.
For #42088
Change-Id: I0bd9bcbe40c0442a268cd1cc315a8a2cbb5adeee
Reviewed-on: https://go-review.googlesource.com/c/go/+/310074
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
These functions take the address of an argument and expect to be able
to reach later arguments from that pointer. This means they must be
laid out sequentially in memory (using ABI0) and all arguments must be
live even though they don't all appear to be referenced. This is
exactly what go:cgo_unsafe_args does.
Without this, GOEXPERIMENT=regabi,regabiargs on windows/amd64 crashes
on runtime startup because the stdcall functions are called with their
arguments in registers, so taking the address of one of them has no
bearing on the memory locations of the following arguments.
With this, GOEXPERIMENT=regabi,regabiargs on windows/amd64 passes
all.bash.
For #40724.
Change-Id: I4a4d6a913f85799b43f61c234d21ebb113a9b527
Reviewed-on: https://go-review.googlesource.com/c/go/+/310733
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
'go run cmd@version' will use the same code.
This changes error messages a bit.
For #42088
Change-Id: Iaed3997a3d27f9fc0e868013ab765f1fb638a0b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/310410
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
PackageOpts is a new struct type accepted by package loading
functions. It initially has two fields: IgnoreImports, and
ModResolveTests. Previously, these were global variables set by
clients. We'll add more to this in the future.
For #40775
Change-Id: I6956e56502de836d3815ce788bdf16fc5f3e5338
Reviewed-on: https://go-review.googlesource.com/c/go/+/310669
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
It looks like these are fixed again for darwin on current tip after CL
111258 marked them to be skipped.
Updates #23168
Change-Id: I4abecee1152ccd4f2d44d76d1acdecb0d6140981
Reviewed-on: https://go-review.googlesource.com/c/go/+/308994
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
There is no x86 GOARCH, this should likely be 386.
Change-Id: I16f1cf5edb0cce156d42ecb621b2ae481c8f1789
Reviewed-on: https://go-review.googlesource.com/c/go/+/308995
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Currently, run.go sets GOEXPERIMENT build tags based on the
*difference* from the baseline experiment configuration, rather than
the absolute experiment configuration. This differs from cmd/go. As a
result, if we set a baseline configuration and don't override it with
a GOEXPERIMENT setting, run.go won't set any GOEXPERIMENT build tags,
instead of setting the tags corresponding to the baseline
configuration.
Fix this by making compile -V=goexperiment produce the full
GOEXPERIMENT configuration, which run.go can then use to set exactly
the right set of build tags.
For #40724.
Change-Id: Ieda6ea62f1a1fabbe8d749d6d09c198fd5ca8377
Reviewed-on: https://go-review.googlesource.com/c/go/+/310171
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
We need to adjust baseline experiment configuration based on the
configured GOOS and GOARCH, so it can't live in goexperiment. Move it
to objabi.
Change-Id: I65f4ce56902c6c1a82735050773c58f2d1320cc6
Reviewed-on: https://go-review.googlesource.com/c/go/+/310169
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The existing implementation allows read / write deadlines to exist
in the past. This updates conditionals to only add to the deadline
when the value is positive.
Fixes: #39177
Change-Id: I841c30ba2849a337e7bc98c8aa136c4527c314ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/235437
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Damien Neil <dneil@google.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Damien Neil <dneil@google.com>
The shift amount should be masked to avoid rotation values
beyond the numer of bits. In this case, if the shift amount
is 0, it should rotate 0, not 32.
Fixes#45589
Change-Id: I1e764497a39d0ec128e29af42352b70c70b2ecc5
Reviewed-on: https://go-review.googlesource.com/c/go/+/310569
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Carlos Eduardo Seo <carlos.seo@linaro.org>
Trust: Carlos Eduardo Seo <carlos.seo@linaro.org>
Only complain about missing type; leave it to type-checking
to decide whether "..." is permitted in the first place.
Fixes#43674.
Change-Id: Icbc8f084e364fe3ac16076406a134354219c08d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/310209
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
This requires consolidating the register move operations into a
single case entry in asmout. These moves are also used to
sign/zero-extend register values.
Combine the three asmout cases for register moves. This allows
AMOVWZ and AMOVW to be handled with the same optab entries.
Likewise, remove the diagnostic error for non-zero constant
loads into R0 using the register move operations, it is not
possible to match this asmout case with a non-zero constant.
Finally, fix the load constant 0 via "MOV[BHW]{,Z} $0, Rx".
These now generate "li Rx, $0" instead of a zero/sign-extend
of the contents of R0.
Change-Id: Ia4a263661582f10feda27ee21cb121e05ea931dc
Reviewed-on: https://go-review.googlesource.com/c/go/+/308190
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Carlos Eduardo Seo <carlos.seo@linaro.org>
Trust: Carlos Eduardo Seo <carlos.seo@linaro.org>
If there is more than the expected single dial, the channel will block.
Allow at least one connection per client, and do the expected cleanup.
Updates #45570
Change-Id: Iaecd45298a7d7c591b7d7b1be13cea6e4a1e2e85
Reviewed-on: https://go-review.googlesource.com/c/go/+/310213
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Trust: Damien Neil <dneil@google.com>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
This is probably unlikely in practice, but when debugging alignment
related issues on ppc64 using very small text section splits, the elf
header could grow beyond the preallocated space and quietly stomp
on the first few text sections.
Change-Id: Ided58aa0b1e60f9da4b3cb277e4ebafcee4ec693
Reviewed-on: https://go-review.googlesource.com/c/go/+/307430
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Lynn Boger <laboger@linux.vnet.ibm.com>
The previous CL introduced macros for transitions from the Windows ABI
to the Go ABI. This CL does the same for SysV and uses them in almost
all places where we transition from the C ABI to the Go ABI.
Compared to Windows, this transition is much simpler and I didn't find
any places that were getting it wrong. But this does let us unify a
lot of code nicely and introduces some degree of abstraction around
these ABI transitions.
Change-Id: Ib6bdecafce587ce18fca4c8300fcf401284a2bcd
Reviewed-on: https://go-review.googlesource.com/c/go/+/309930
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
There are several assembly functions that transition from the Windows
ABI to the Go ABI. These all need to save all registers that are
callee-save in the Windows ABI and caller-save in the Go ABI and
prepare the register state for Go. However, they all do this slightly
differently and most of them don't save the necessary XMM registers
for this transition (which could corrupt them in the C caller).
Furthermore, now that we have a carefully specified Go ABI, it's clear
that none of these actually get all of the details 100% right.
So, unify this code into two macros in a shared header in
runtime/cgo/abi_amd64.h that handle all necessary registers and setup
and use these macros everywhere on Windows that handles transitions
from C to Go.
Change-Id: I62f41345a507aad1ca383814ac8b7e2a9ffb821e
Reviewed-on: https://go-review.googlesource.com/c/go/+/309769
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This function bounces between the C and Go ABIs a few times. This CL
narrows the scope of the Go -> C transition to just around the branch
that calls C. This lets us take advantage of C callee-save registers
to simplify the code a little.
Change-Id: I1ffa0b9e50325425c5ec66596978aeb6450a6b57
Reviewed-on: https://go-review.googlesource.com/c/go/+/309929
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
CL 308931 ported several runtime assembly functions to ABIInternal so
that compiler-generated ABIInternal calls don't go through ABI
wrappers, but it missed the runtime assembly functions that are
actually defined in internal/bytealg.
This eliminates the cost of wrappers for the BleveQuery and
GopherLuaKNucleotide benchmarks, but there's still more to do for
Tile38.
0-base 1-wrappers
sec/op sec/op vs base
BleveQuery 6.507 ± 0% 6.477 ± 0% -0.46% (p=0.004 n=20)
GopherLuaKNucleotide 30.39 ± 1% 30.34 ± 0% ~ (p=0.301 n=20)
Tile38IntersectsCircle100kmRequest 1.038m ± 1% 1.080m ± 2% +4.03% (p=0.000 n=20)
For #40724.
Change-Id: I0b722443f684fcb997b1d70802c5ed4b8d8f9829
Reviewed-on: https://go-review.googlesource.com/c/go/+/310184
Trust: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
According the armv8-a specification, the destination register of the ADDS/ADDSW/
SUBS/SUBSW instructions can not be RSP, the current implementation does not
check this and encodes this wrong instruction format as a CMN instruction. This
CL adds a check and test cases for this situation.
Change-Id: I92cc2f8e17dbda70f0dce8fddf1ca6d5d7730589
Reviewed-on: https://go-review.googlesource.com/c/go/+/309989
Reviewed-by: eric fang <eric.fang@arm.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Trust: eric fang <eric.fang@arm.com>
Run-TryBot: eric fang <eric.fang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Updates #45448
Change-Id: I2e79ae6b9cf43a481aa703578712619ea344e421
Reviewed-on: https://go-review.googlesource.com/c/go/+/310212
Trust: Damien Neil <dneil@google.com>
Run-TryBot: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Change-Id: I28a1910890659aaa449ffd2a847cd4ced5a8600d
Reviewed-on: https://go-review.googlesource.com/c/go/+/310211
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
Add in some missing global assignment ops to the list of globals ops
that should be traversed to look for generic function instantiations.
The most common other one for global assigments (and the relevant one
for this bug) is OAS2FUNC, but also look at global assigments with
OAS2DOTTYPE, OAS2MAPR, OAS2RECV, and OASOP.
Bonus small fix: get rid of -G=3 case in ir.IsAddressable. Now that we
don't call the old typechecker from noder2, we don't need this -G-3
check anymore.
Fixes#45547.
Change-Id: I75fecec55ea0d6f62e1c2294d4d77447ed9be6ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/310210
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
