This CL removes all unused code from bimport.go and bexport.go.
In the interest of keeping this CL strictly delete-only and easier to
review, the task of consolidating the vestigial code elsewhere is left
to future CLs.
Change-Id: Ib757cc27e3fe814cbf534776d026e4d4cddfc6db
Reviewed-on: https://go-review.googlesource.com/c/139338
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
The existing code for encoding 'for' loops in exported, inlineable
functions incorrectly assumed that the 'Right' field points to an
'expression' node. Adjusted the code to be able to handle any kind
of node. Made matching changes for the binary and indexed exporter.
This only shows up together with other pending compiler changes that
enable exporting of such functions which contain for loops.
No tests yet because we can't test this w/o those pending compiler
changes. Once those changes are in, this code will be tested implicitly.
However, the changes were tested manually together with the patches
described in the issue.
Fixes#25222.
Change-Id: I54babb87e5d665d2c1ef6116c1de1b8c50b1138e
Reviewed-on: https://go-review.googlesource.com/119595
Reviewed-by: David Chase <drchase@google.com>
This reduces the API surface of Type slightly (for #25056), but also
makes it more consistent with the reflect and go/types APIs.
Passes toolstash-check.
Change-Id: Ief9a8eb461ae6e88895f347e2a1b7b8a62423222
Reviewed-on: https://go-review.googlesource.com/109138
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
For struct fields and methods, Field.Nname was only used to store
position information, which means we're allocating an entire ONAME
Node+Name+Param structure just for one field. We can optimize away
these ONAME allocations by instead adding a Field.Pos field.
Unfortunately, we can't get rid of Field.Nname, because it's needed
for function parameters, so Field grows a little bit and now has more
redundant information in those cases. However, that was already the
case (e.g., Field.Sym and Field.Nname.Sym), and it's still a net win
for allocations as demonstrated by the benchmarks below.
Additionally, by moving the ONAME allocation for function parameters
to funcargs, we can avoid allocating them for function parameters that
aren't used in corresponding function bodies (e.g., interface methods,
function-typed variables, and imported functions/methods without
inline bodies).
name old time/op new time/op delta
Template 254ms ± 6% 251ms ± 6% -1.04% (p=0.000 n=487+488)
Unicode 128ms ± 7% 128ms ± 7% ~ (p=0.294 n=482+467)
GoTypes 862ms ± 5% 860ms ± 4% ~ (p=0.075 n=488+471)
Compiler 3.91s ± 4% 3.90s ± 4% -0.39% (p=0.000 n=468+473)
name old user-time/op new user-time/op delta
Template 339ms ±14% 336ms ±14% -1.02% (p=0.001 n=498+494)
Unicode 176ms ±18% 176ms ±25% ~ (p=0.940 n=491+499)
GoTypes 1.13s ± 8% 1.13s ± 9% ~ (p=0.157 n=496+493)
Compiler 5.24s ± 6% 5.21s ± 6% -0.57% (p=0.000 n=485+489)
name old alloc/op new alloc/op delta
Template 38.3MB ± 0% 37.3MB ± 0% -2.58% (p=0.000 n=499+497)
Unicode 29.1MB ± 0% 29.1MB ± 0% -0.03% (p=0.000 n=500+493)
GoTypes 116MB ± 0% 115MB ± 0% -0.65% (p=0.000 n=498+499)
Compiler 492MB ± 0% 487MB ± 0% -1.00% (p=0.000 n=497+498)
name old allocs/op new allocs/op delta
Template 364k ± 0% 360k ± 0% -1.15% (p=0.000 n=499+499)
Unicode 336k ± 0% 336k ± 0% -0.01% (p=0.000 n=500+493)
GoTypes 1.16M ± 0% 1.16M ± 0% -0.30% (p=0.000 n=499+499)
Compiler 4.54M ± 0% 4.51M ± 0% -0.58% (p=0.000 n=494+495)
Passes toolstash-check -gcflags=-dwarf=false. Changes DWARF output
because position information is now tracked more precisely for
function parameters.
Change-Id: Ib8077d70d564cc448c5e4290baceab3a4396d712
Reviewed-on: https://go-review.googlesource.com/108217
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This CL moves all of the logic for wiring up imported declarations
into export.go, so that it can be reused by the indexed importer
code. While here, increase symmetry across routines.
Passes toolstash-check.
Change-Id: I1ccec5c3999522b010e4d04ed56b632fd4d712d9
Reviewed-on: https://go-review.googlesource.com/107621
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
A package's height is defined as the length of the longest import path
between itself and a leaf package (i.e., package with no imports).
We can't rely on knowing the path of the package being compiled, so
package height is useful for defining a package ordering.
Updates #24693.
Change-Id: I965162c440b6c5397db91b621ea0be7fa63881f1
Reviewed-on: https://go-review.googlesource.com/105038
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Previously, constant pointer-typed expressions could use either Mpint
or NilVal as their Val depending on their construction, but const.go
expects each type to have a single corresponding Val kind.
This CL changes pointer-typed expressions to exclusively use Mpint.
Fixes#21221.
Change-Id: I6ba36c9b11eb19a68306f0b296acb11a8c254c41
Reviewed-on: https://go-review.googlesource.com/105315
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
There were multiple ad hoc ways to create method symbols, with subtle
and confusing differences between them. This CL unifies them into a
single well-documented encoding and implementation.
This introduces some inconsequential changes to symbol format for the
sake of simplicity and consistency. Two notable changes:
1) Symbol construction is now insensitive to the package currently
being compiled. Previously, non-exported methods on anonymous types
received different method symbols depending on whether the method was
local or imported.
2) Symbols for method values parenthesized non-pointer receiver types
and non-exported method names, and also always package-qualified
non-exported method names. Now they use the same rules as normal
method symbols.
The methodSym function is also now stricter about rejecting
non-sensical method/receiver combinations. Notably, this means that
typecheckfunc needs to call addmethod to validate the method before
calling declare, which also means we no longer emit errors about
redeclaring bogus methods.
Change-Id: I9501c7a53dd70ef60e5c74603974e5ecc06e2003
Reviewed-on: https://go-review.googlesource.com/104876
Reviewed-by: Robert Griesemer <gri@golang.org>
Inl, Inldcl, and InlCost are only applicable to functions with bodies
that can be inlined, so pull them out into a separate Inline type to
make understanding them easier.
A side benefit is that we can check if a function can be inlined by
just checking if n.Func.Inl is non-nil, which simplifies handling of
empty function bodies.
While here, remove some unnecessary Curfn twiddling, and make imported
functions use Inl.Dcl instead of Func.Dcl for consistency for local
functions.
Passes toolstash-check.
Change-Id: Ifd4a80349d85d9e8e4484952b38ec4a63182e81f
Reviewed-on: https://go-review.googlesource.com/104756
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Previously, n.Pos was reassigned to lineno when declare was called,
which might not match where the identifier actually appeared in the
source. This caused a loss of position precision for function
parameters (which were all declared at the last parameter's position),
and required some clumsy workarounds in bimport.go.
This CL changes declare to leave n.Pos alone and also fixes a few
places where n.Pos was not being set correctly.
Change-Id: Ibe5b5fd30609c684367207df701f9a1bfa82867f
Reviewed-on: https://go-review.googlesource.com/104275
Reviewed-by: Robert Griesemer <gri@golang.org>
Add helper methods that validate n.Op and convert to/from the
appropriate type.
Notably, there was a lot of code in walk.go that thought setting
Etype=1 on an OADDR node affected escape analysis.
Passes toolstash-check.
TBR=marvin
Change-Id: Ieae7c67225c1459c9719f9e6a748a25b975cf758
Reviewed-on: https://go-review.googlesource.com/99535
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
There were only two large classes of use for these variables:
1) Testing "funcdepth != 0" or "funcdepth > 0", which is equivalent to
checking "Curfn != nil".
2) In oldname, detecting whether a closure variable has been created
for the current function, which can be handled by instead testing
"n.Name.Curfn != Curfn".
Lastly, merge funcstart into funchdr, since it's only called once, and
it better matches up with funcbody now.
Passes toolstash-check.
Change-Id: I8fe159a9d37ef7debc4cd310354cea22a8b23394
Reviewed-on: https://go-review.googlesource.com/99076
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Binary import sometimes constructs nodes using functions
that use the global lineno for the Position. This causes
spurious numbers to appear in the assembly and the
debugging output.
Fix (targeted, because late in the cycle): save and restore
lineno around bimport calls known to use lineno-sensitive
functions.
Updates #22600.
(Comment: "This is a weird line to step through")
Change-Id: I9c4094670380609fe4b6696443fb02579521c596
Reviewed-on: https://go-review.googlesource.com/80115
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Previously, anytime we exported a function or method declaration
(which includes methods for every type transitively exported), we
included the inline function bodies, if any. However, in many cases,
it's impossible (or at least very unlikely) for the importing package
to call the method.
For example:
package p
type T int
func (t T) M() { t.u() }
func (t T) u() {}
func (t T) v() {}
T.M and T.u are inlineable, and they're both reachable through calls
to T.M, which is exported. However, t.v is also inlineable, but cannot
be reached.
Exception: if p.T is embedded in another type q.U, p.T.v will be
promoted to q.U.v, and the generated wrapper function could have
inlined the call to p.T.v. However, in practice, this doesn't happen,
and a missed inlining opportunity doesn't affect correctness.
To implement this, this CL introduces an extra flood fill pass before
exporting to mark inline bodies that are actually reachable, so the
exporter can skip over methods like t.v.
This reduces Kubernetes build time (as measured by "time go build -a
k8s.io/kubernetes/cmd/...") on an HP Z620 measurably:
== before ==
real 0m44.658s
user 11m19.136s
sys 0m53.844s
== after ==
real 0m41.702s
user 10m29.732s
sys 0m50.908s
It also significantly cuts down the cost of enabling mid-stack
inlining (-l=4):
== before (-l=4) ==
real 1m19.236s
user 20m6.528s
sys 1m17.328s
== after (-l=4) ==
real 0m59.100s
user 13m12.808s
sys 0m58.776s
Updates #19348.
Change-Id: Iade58233ca42af823a1630517a53848b5d3c7a7e
Reviewed-on: https://go-review.googlesource.com/74110
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Previously, we were treating cross-package function calls as free for
inlining budgeting.
In theory, we should be able to recompute InlCost from the
exported/reimported function bodies. However, that process mutates the
structure of the Node AST enough that it doesn't preserve InlCost. To
avoid unexpected issues, just record and restore InlCost in the export
data.
Fixes#19261.
Change-Id: Iac2bc0d32d4f948b64524aca657051f9fc96d92d
Reviewed-on: https://go-review.googlesource.com/70151
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
These were previously only relevant for recording scoping level so
that invalid 'fallthrough' statements could be rejected. However,
that's handled differently since CL 61130 (in particular, there's no
use of types.Block anymore), so these calls can be safely removed.
Passes toolstash-check.
Change-Id: I8631b156594df85b8d39f57acad3ebcf099d52f9
Reviewed-on: https://go-review.googlesource.com/64810
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Previously, we used OXFALL vs OFALL to distinguish fallthrough
statements that had been validated. Because in the Node AST we flatten
statement blocks, OXCASE and OXFALL needed to keep track of their
block scopes for this purpose.
Now that we have an AST that keeps these separate, we can just perform
the validation earlier.
Passes toolstash-check.
Fixes#14540.
Change-Id: I8421eaba16c2b3b72c9c5483b5cf20b14261385e
Reviewed-on: https://go-review.googlesource.com/61130
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
We only export packages that typechecked successfully, and OTYPE nodes
will always have their Type field set.
Changes the package export format, but only in the compiler-specific
section. No version bump necessary.
Change-Id: I722f5827e73948fceb0432bc8b3b22471fea8f61
Reviewed-on: https://go-review.googlesource.com/63273
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
Discovered while debugging CL 53644.
No test case because these are purely internal conversions that should
never end up resulting in compiler warnings or even generated code.
Updates #19683.
Change-Id: I0d9333ef2c963fa22eb9b5335bb022bcc9b25708
Reviewed-on: https://go-review.googlesource.com/58190
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This reverts commit f612cd704a.
Reason for revert: We thought the original change had broken the
linux/amd64 and linux/386 builders, but it turned out to be a problem
with the build infrastructure, not the change.
Change-Id: Ic3318a63464fcba8d845ac04494115a7ba620364
Reviewed-on: https://go-review.googlesource.com/55050
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This reverts commit f0b3626904.
Reason for revert: this change caused the runtime tests on all linux/amd64 and linux/386 builders to timeout
Change-Id: Idf8cfdfc84540e21e8da403e74df5596a1d9327b
Reviewed-on: https://go-review.googlesource.com/54490
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Mostly node and position parameters that are no longer used.
Also remove an unnecessary node variable while at it.
Found with github.com/mvdan/unparam.
Change-Id: I88f9bd5d20bfc5b0f6f63ea81869daa246175061
Reviewed-on: https://go-review.googlesource.com/54130
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
If we've already imported a named type, then there's no need to
process its associated methods except to validate that the signature
matches the existing known method.
However, the current import code still creates a new function node for
each method, saves its inline body (if any), and adds the node to the
global importlist. Because of this, the duplicate methods are never
garbage collected.
This CL changes the compiler to avoid amassing uncollectable garbage
or performing any unnecessary processing.
This is particularly noticeable for protobuf-heavy code. For the
motivating Go package, this CL reduced compile max-RSS from ~12GB to
~3GB and compile time from ~65s to ~50s.
Passes toolstash -cmp for std, cmd, and k8s.io/kubernetes/cmd/....
Change-Id: Ib53ba9f2ad3212995671cf6ba220ee8a56d8d009
Reviewed-on: https://go-review.googlesource.com/51331
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This doesn't change the existing restriction with disallows
spaces in import paths (as found in an import declaration).
It simply permits packages to be under a directory name that
may contain spaces.
Verified manually that it works. This could use a test, but the
change is trivial. We also can't use the existing test framework
(under test/) because the way those tests are run with test/run.go,
the mechanims for compiling a directory, even if it contains blanks
it its name, does't produce compiler paths with blanks
(the compilation is local).
Fixes#20306.
Change-Id: I6cbffb86c3394347897c3c94b110da0aadc5bfdf
Reviewed-on: https://go-review.googlesource.com/46001
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
isifacemethod accessed thisT without checking if it was initialized,
opening the possibility for a bug during type checking. Give better
name, move it to package types, and provide accessor instead.
Change-Id: I29ffc408252a4ba4ef1de218fa154397786c9be6
Reviewed-on: https://go-review.googlesource.com/41673
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
More steps towards simpler symbol handling:
- Pushdcl's incoming pos argument, saved in a newly pushed *Sym, was always
immediately overwritten by the Lastlineno value of the saved *Sym.
- Markdcl's incoming pos argument, saved in the stack mark *Sym, was not
restored when the stack mark was popped.
- Popdcl always maintained the most recent Lastlineno for a *Sym given
by package and name, making it unnecessary to save Lastlineno in the
first place. Removed Lastlineno from the set of fields that need saving,
and simplified Popdcl.
Change-Id: Ie93da1fbd780dcafc2703044e781c0c6298df569
Reviewed-on: https://go-review.googlesource.com/41390
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
That's where it belongs. Also, moved pkgMap and pkgs globals.
Change-Id: I531727fe5ce162c403efefec82f4cc90afa326d7
Reviewed-on: https://go-review.googlesource.com/41071
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This reverts commit c8b889cc48.
Reason for revert: broke noopt build, compiler performance regression, new Curfn uses
Let's fix those and then try this again.
Change-Id: Icc3cad1365d04cac8fd09da9dbb0bbf55c13ef44
Reviewed-on: https://go-review.googlesource.com/39991
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Change compiler and linker to emit DWARF lexical blocks in debug_info.
Version of debug_info is updated from DWARF v.2 to DWARF v.3 since version 2
does not allow lexical blocks with discontinuous ranges.
Second attempt at https://go-review.googlesource.com/#/c/29591/
Remaining open problems:
- scope information is removed from inlined functions
- variables in debug_info do not have DW_AT_start_scope attributes so a
variable will shadow other variables with the same name as soon as its
containing scope begins, before its declaration.
Updates golang/go#12899, golang/go#6913
Change-Id: I0e260a45b564d14a87b88974eb16c5387cb410a5
Reviewed-on: https://go-review.googlesource.com/36879
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
They are in the types package, no need to mention the Type suffix.
Change-Id: Ie4fe1e3c1793514145e33f9df373d715f63e1aad
Reviewed-on: https://go-review.googlesource.com/39911
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
- created new package cmd/compile/internal/types
- moved Pkg, Sym, Type to new package
- to break cycles, for now we need the (ugly) types/utils.go
file which contains a handful of functions that must be installed
early by the gc frontend
- to break cycles, for now we need two functions to convert between
*gc.Node and *types.Node (the latter is a dummy type)
- adjusted the gc's code to use the new package and the conversion
functions as needed
- made several Pkg, Sym, and Type methods functions as needed
- renamed constructors typ, typPtr, typArray, etc. to types.New,
types.NewPtr, types.NewArray, etc.
Passes toolstash-check -all.
Change-Id: I8adfa5e85c731645d0a7fd2030375ed6ebf54b72
Reviewed-on: https://go-review.googlesource.com/39855
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Followup to previous typenod CL. Changes export data format, but only
the compiler-specific section, so no version bump.
Change-Id: I0c21737141f3d257366b29b2a9211bc7217c39ee
Reviewed-on: https://go-review.googlesource.com/39797
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Pass around the imported package explicitly instead of relying
on a global variable.
Unfortunately we still need a global variable to communicate to
the typechecker that we're in an import, but the semantic load
is significantly reduced as it's just a bool, set/reset in a
couple of places only.
Change-Id: I4ebeae4064eb76ca0c4e2a15e4ca53813f005c29
Reviewed-on: https://go-review.googlesource.com/38595
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
First step towards removing global var importpkg.
Change-Id: Ifdda7c295e5720a7ff2da9baea17f03f190d48fa
Reviewed-on: https://go-review.googlesource.com/38594
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Previously, we handled recursive interfaces by deferring typechecking
of interface methods, while eagerly expanding interface embeddings.
This CL switches to eagerly evaluating interface methods, and
deferring expanding interface embeddings to dowidth. This allows us to
detect recursive interface embeddings with the same mechanism used for
detecting recursive struct embeddings.
Updates #16369.
Change-Id: If4c0320058047f8a2d9b52b9a79de47eb9887f95
Reviewed-on: https://go-review.googlesource.com/38391
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Mapping all empty interfaces onto the same Type
allows better reuse of the ptrTo and sliceOf
Type caches for *interface{} and []interface{}.
This has little compiler performance impact now,
but it will be helpful in the future,
when we will eagerly populate some of those caches.
Passes toolstash-check.
Change-Id: I17daee599a129b0b2f5f3025c1be43d569d6782c
Reviewed-on: https://go-review.googlesource.com/38344
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
By clearing out t.nod in copytype, we effectively lose the reference
from a Type back to its declaring OTYPE Node. This means later in
typenamesym when we add typenod(t) to signatlist, we end up creating a
new OTYPE Node. Moreover, this Node's position information will depend
on whatever context it happens be needed, and will be used for the
Type's position in the export data.
Updates #19391.
Change-Id: Ied93126449f75d7c5e3275cbdcc6fa657a8aa21d
Reviewed-on: https://go-review.googlesource.com/37870
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>