Now that the only remaining ir.Node implementation that is stored
(directly) into ssa.Aux, we can rewrite all of the conversions between
ir.Node and ssa.Aux to use *ir.Name instead.
rf doesn't have a way to rewrite the type switch case clauses, so we
just use sed instead. There's only a handful, and they're the only
times that "case ir.Node" appears anyway.
The next CL will move the tag method declarations so that ir.Node no
longer implements ssa.Aux.
Passes buildall w/ toolstash -cmp.
Updates #42982.
[git-generate]
cd src/cmd/compile/internal
sed -i -e 's/case ir.Node/case *ir.Name/' gc/plive.go */ssa.go
cd ssa
rf '
ex . ../gc {
import "cmd/compile/internal/ir"
var v *Value
v.Aux.(ir.Node) -> v.Aux.(*ir.Name)
var n ir.Node
var asAux func(Aux)
strict n # only match ir.Node-typed expressions; not *ir.Name
implicit asAux # match implicit assignments to ssa.Aux
asAux(n) -> n.(*ir.Name)
}
'
Change-Id: I3206ef5f12a7cfa37c5fecc67a1ca02ea4d52b32
Reviewed-on: https://go-review.googlesource.com/c/go/+/275789
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
OpFwdRef is the only SSA value that needs the ability to store an
arbitrary ir.Node in its Aux field. Every other SSA value always uses
an *ir.Name.
This CL introduces FwdRefAux, which wraps an ir.Node and implements
the ssa.Aux tag interface, so that a subsequent refactoring can change
ir.Node to not implement ssa.Aux.
Passes buildall w/ toolstash -cmp.
Updates #42982.
Change-Id: Id1475b28847579573cd376e82f28761d84cd1c23
Reviewed-on: https://go-review.googlesource.com/c/go/+/275788
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Position independent code expects that R25 (aka $t9) contains the address of the
called function. As such, use R25 when calling from sigfwd.
Change-Id: I66b2b9bfa1f1bb983c7385eb2eaa19d9cd87d9fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/275893
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This was already documented as always being an ONAME, so it just
needed a few type assertion changes.
Passes buildall w/ toolstash -cmp.
Updates #42982.
Change-Id: I61f4b6ebd57c43b41977f4b37b81fe94fb11a723
Reviewed-on: https://go-review.googlesource.com/c/go/+/275757
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
It's currently hard to automate refactorings around the Value.Aux
field, because we don't have any static typing information for it.
Adding a tag interface will make subsequent CLs easier and safer.
Passes buildall w/ toolstash -cmp.
Updates #42982.
Change-Id: I41ae8e411a66bda3195a0957b60c2fe8a8002893
Reviewed-on: https://go-review.googlesource.com/c/go/+/275756
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
For #40281Fixes#42959
Change-Id: Ibc4769fda1592a1373ec720ea30baf319c0a0136
Reviewed-on: https://go-review.googlesource.com/c/go/+/274448
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Russ, is this what you meant?
Change-Id: I27d2847811c6eabd94358e435eb3eb4bc8cfaa9e
Reviewed-on: https://go-review.googlesource.com/c/go/+/275712
Trust: Keith Randall <khr@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The plan was always to export them once we remove the getters
and setters, but do it a bit early, with _ suffixes as needed, so that
the reflection-based ir.Dump can access the fields.
Passes buildall w/ toolstash -cmp.
[git-generate]
cd src/cmd/compile/internal/ir
rf '
mv AddStringExpr.list AddStringExpr.List_
mv BlockStmt.list BlockStmt.List_
mv CallExpr.body CallExpr.Body_
mv CaseStmt.list CaseStmt.List_
mv CaseStmt.body CaseStmt.Body_
mv ClosureExpr.fn ClosureExpr.Func_
mv CompLitExpr.list CompLitExpr.List_
mv ForStmt.body ForStmt.Body_
mv Func.body Func.Body_
mv IfStmt.body IfStmt.Body_
mv InlinedCallExpr.body InlinedCallExpr.Body_
mv RangeStmt.body RangeStmt.Body_
mv SliceExpr.list SliceExpr.List_
mv SliceHeaderExpr.lenCap SliceHeaderExpr.LenCap_
mv TypeSwitchGuard.name TypeSwitchGuard.Name_
'
go generate
Change-Id: I06e65920cecbcc51bea2254f52fcd7d5c5d0dc90
Reviewed-on: https://go-review.googlesource.com/c/go/+/275784
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The next CL will rename Func.body to Func.Body_.
At some point in the future we will rename it to Func.Body.
Make the generator not get confused.
Passes buildall w/ toolstash -cmp.
Change-Id: Iee3f4915889a8287377bf3304d5b9250a909477e
Reviewed-on: https://go-review.googlesource.com/c/go/+/275783
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
On ir.Node, ir.Nodes, and ir.Op, # is ignored, so %#v is %v.
On ir.Node, %S is the same as %v.
On types.Type, # is ignored, so %#L is %L, %#v is %v.
On types.Type, 0 is ignored, so %0S is %S.
Rewrite all these using go test cmd/compile -r, plus a
few multiline formats mentioning %0S on types updated by hand.
Now the formats used in the compiler match the documentation
for the format methods, a minor miracle.
Passes buildall w/ toolstash -cmp.
Change-Id: I3d4a3fae543145a68da13eede91166632c5b1ceb
Reviewed-on: https://go-review.googlesource.com/c/go/+/275782
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The format map is going to keep growing as we add more use of
concrete node types. Stop that by reporting all Node implementations
as Node.
Also, there's little point to reporting uses of %v, %p, %T, nor to reporting
formatting of basic types like int and []byte. Remove those too.
(Vet takes care of mistakes involving basic types now.)
Passes buildall w/ toolstash -cmp.
Change-Id: Ia9fb39b401c29bf0c76ffebaa24836c70acd773f
Reviewed-on: https://go-review.googlesource.com/c/go/+/275781
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Some cleanup left over from moving the Type and Sym formatting to types.
And then document what the type formats are, now that it's clear.
Passes buildall w/ toolstash -cmp.
Change-Id: I35cb8978f1627db1056cb8ab343ce6ba6c99afad
Reviewed-on: https://go-review.googlesource.com/c/go/+/275780
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Move the printing of types.Type and types.Sym out of ir
into package types, where it properly belongs. This wasn't
done originally (when the code was in gc) because the Type
and Sym printing was a bit tangled up with the Node printing.
But now they are untangled and can move into the correct
package.
This CL is automatically generated.
A followup CL will clean up a little bit more by hand.
Passes buildall w/ toolstash -cmp.
[git-generate]
cd src/cmd/compile/internal/ir
rf '
mv FmtMode fmtMode
mv FErr fmtGo
mv FDbg fmtDebug
mv FTypeId fmtTypeID
mv FTypeIdName fmtTypeIDName
mv methodSymName SymMethodName
mv BuiltinPkg LocalPkg BlankSym OrigSym NumImport \
fmtMode fmtGo symFormat sconv sconv2 symfmt SymMethodName \
BasicTypeNames fmtBufferPool InstallTypeFormats typeFormat tconv tconv2 fldconv FmtConst \
typefmt.go
mv typefmt.go cmd/compile/internal/types
'
cd ../types
mv typefmt.go fmt.go
Change-Id: I6f3fd818323733ab8446f00594937c1628760b27
Reviewed-on: https://go-review.googlesource.com/c/go/+/275779
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
It turns out that the FmtFlag is really only tracking the FmtLong and FmtShort bits,
and the others simply mirror the state of the FmtMode and are copied out and
back in repeatedly.
Simplify to FmtFlag being the verb itself ('S', 'L', or 'v').
Now there is only one formatting enumeration, making it a bit
easier to understand what's going on.
Passes buildall w/ toolstash -cmp.
Change-Id: I85bde2183eb22228fcf46d19d003401d588d9825
Reviewed-on: https://go-review.googlesource.com/c/go/+/275778
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This code is now hardly used and not worth the complexity.
It also tangles together Nodes and Types in a way that keeps
this code in package ir instead of package types.
Passes buildall w/ toolstash -cmp.
Change-Id: I2e829c1f6b602acbdc8ab4aac3b798f9ded762ef
Reviewed-on: https://go-review.googlesource.com/c/go/+/275777
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Narrow the interface between package ir and package types
to make it easier to clean up the type formatting code all in one place.
Also introduce ir.BlankSym for use by OrigSym, so that later
OrigSym can move to package types without needing to reference
a variable of type ir.Node.
Passes buildall w/ toolstash -cmp.
Change-Id: I39fa419a1c8fb3318203e31cacc8d06399deeff9
Reviewed-on: https://go-review.googlesource.com/c/go/+/275776
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
nconvFmt calls base.Fatalf if mode is anything but FErr,
proving that the only formats that matter for nodes are
plain %v, %S, and %L. And the nodes formatter can only get to %v.
(%S and %v are the same; we'll clean that up separately.)
Node and Nodes can therefore ignore mode, and all the mode
code can be removed from those implementations, removing
quite a few layers of abstraction.
Op similarly only runs in one mode and can be simplified.
Passes buildall w/ toolstash -cmp.
Change-Id: Ibfd845033e9c68181a20fb81c8f3dd428463920a
Reviewed-on: https://go-review.googlesource.com/c/go/+/275775
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The Node printing code is tangled up due to the multiple printing modes.
Split out the Dump mode into its own code, which clarifies it considerably.
We are going to have to change the code for the new Node representations,
so it is nice to have it in an understandable form first.
The output of Dump is unchanged except for the removal of spurious
mid-Dump blank lines that have been printed for a while but don't
really make sense and appear to be a bug.
The %+v verb on Op prints the name ("ADD" not "+"), matching
%+v on Node and %+v on Nodes to get Dump and DumpList formats.
Passes buildall w/ toolstash -cmp.
Change-Id: I07f0f245859f1f785e10bdd671855ca43c51b545
Reviewed-on: https://go-review.googlesource.com/c/go/+/275774
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This code is a few layer of abstraction stacked up on top
of each other, and they're hard to see all at the same time
because the file is pretty mixed up. As much as I try to avoid
code rearrangement to keep history, this one is long overdue.
A followup CL will cut out some of the layers, and the diff will be
much clearer what's going on with the code ordered with
callers near callees, as it is now.
Passes buildall w/ toolstash -cmp.
Change-Id: Iffc49d43cf4be9fab47e2dd59a5f98930573350f
Reviewed-on: https://go-review.googlesource.com/c/go/+/275773
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This is unreachable code - the only way short can be true is
if verb == 'S', but jconv is only called when verb == 'j'.
Simplify by removing.
Passes buildall w/ toolstash -cmp.
Change-Id: I27bd38319f72215069e940b320b5c82608e2651a
Reviewed-on: https://go-review.googlesource.com/c/go/+/275772
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Ending typecheck1 in the switch makes it safe for each case
to do an appropriate type assertion. The main change is dropping
the computation of "ok" and using the syntax nodes themselves
to decide what's OK.
Passes buildall w/ toolstash -cmp.
Change-Id: I2a1873a51e3f1194d74bb87a6653cb9857a02a1b
Reviewed-on: https://go-review.googlesource.com/c/go/+/275444
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Add Node method generator by Matthew Dempsky,
lightly adapted to account for a few special cases.
No more writing these by hand.
Change-Id: I6933b895df666928b851bddf81b994799c0c97f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/275434
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
sys/unistd.h only exists in glibc and not in musl so use the standard
location. This is a regression from CL 210639
Change-Id: Idd4c75510d9829316b44300c36c34df6d667cc05
GitHub-Last-Rev: 0fa4162f1c
GitHub-Pull-Request: golang/go#43038
Reviewed-on: https://go-review.googlesource.com/c/go/+/275732
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Andrew G. Morgan <agm@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Filippo Valsorda <filippo@golang.org>
The gofrontend code would in some circumstances incorrectly generate a
type descriptor for an alias type, causing the type to fail to be
equal to the unaliased type.
Change-Id: I47d33b0bfde3c72a9a186049539732bdd5a6a96e
Reviewed-on: https://go-review.googlesource.com/c/go/+/275632
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
For #40700
Change-Id: Idea442d45d18ca8cedc0b160df23eac6b86755ef
Reviewed-on: https://go-review.googlesource.com/c/go/+/275677
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Enabled fixedbugs/issue8183.go for run.go with new typechecker
now that issue is fixed.
Fixes#42992.
Updates #42991.
Change-Id: I23451999983b740d5f37ce3fa75ee756daf1a44f
Reviewed-on: https://go-review.googlesource.com/c/go/+/275517
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
If an interface contains a blank method, that's already an error. No
need for useless follow-up error messages about not implementing them.
Fixes#42964.
Change-Id: I5bf53a8f27d75d4c86c61588c5e2e3e95563d320
Reviewed-on: https://go-review.googlesource.com/c/go/+/275294
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
In the past, we had a lot of trouble with misusing *types.Sym
throughout the frontend, so I tried to push us towards always passing
around ONAMEs instead. But for constructing and writing out the symbol
indexes for the indexed export data, keying by *types.Sym is exactly
what we want.
Passes buildall w/ toolstash -cmp.
Updates #42982.
Change-Id: Idd8f1fb057d75a52a34ebc7788d9332fb49caf8d
Reviewed-on: https://go-review.googlesource.com/c/go/+/275755
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
All of the uses were already using *ir.Func index operands, so only
needs the map type itself updated.
Passes buildall w/ toolstash -cmp.
Updates #42982.
Change-Id: I568d8601f3eb077e07e887f2071aa1a2667d803c
Reviewed-on: https://go-review.googlesource.com/c/go/+/275754
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Similar to the previous CL, the only two users of NodeQueue only
needed it for tracking objects, not arbitrary AST nodes. So change
it's signature to use *Name instead of Node.
This does require a tweak to the nowritebarrierrec checker, because
previously it was pushing the ODCLFUNC *Func pointers into the queue,
whereas now we push the ONAME/PFUNC *Name pointers instead. However,
it's trivial and safe to flip between them.
Also, this changes a handful of export-related code from Node to
*Name, to avoid introducing type assertions within iexport.go.
Passes buildall w/ toolstash -cmp.
Updates #42982.
Change-Id: I867f9752121509fc3da753978c6a41d5015bc0ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/275753
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
The only user of NodeSet (computing initialization dependencies) only
needs to store *Names in this structure. So change its definition to
match that need, and update the code in initorder.go accordingly.
Passes buildall w/ toolstash -cmp.
Updates #42982.
Change-Id: I181a8aaf9bc71e88f4ac009c4f381a718080e48f
Reviewed-on: https://go-review.googlesource.com/c/go/+/275752
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
According to [1], this function returns NULL when it errors, rather than
INVALID_HANDLE_VALUE, which other Win32 functions return. This was
pointed out in CL 273446 for the x/sys package, and this patch here
cleans it up for the syscall package and updates the vendored x/sys
package using the usual `go get/go mod vendor` dance. The function is
currently in use by crypto/x509/root_windows.go, which calls
CertOpenStore(CERT_STORE_PROV_MEMORY), which I assume can fail under OOM
or other weird conditions. Quick reversing indicates that [1] is
correct, as there's a `xor eax, eax` in the error paths of the function
just before jumping to the epilogue.
[1] https://docs.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certopenstore#return-value
Change-Id: I77c0b0319c13313212f8710785252c494da56ed5
Reviewed-on: https://go-review.googlesource.com/c/go/+/273827
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Trust: Alex Brainman <alex.brainman@gmail.com>
Pulls in a fix to make versioned import paths more readable in pprof's
graph view.
Updated via the instructions in README.vendor.
Updates #36905
Change-Id: I6a91de0f4ca1be3fc69d8e1a39ccf4f5bd0387ef
Reviewed-on: https://go-review.googlesource.com/c/go/+/275513
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Change-Id: I103e3eeacd5b11efd63c965482a626878ba5ac81
Reviewed-on: https://go-review.googlesource.com/c/go/+/275216
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>
Currently, because we use the same *Name to represent both declaration
and uses of an object, it's ambiguous what "n1 == n2" means when
comparing two Node values. It can mean any of: Are these the same
syntactic element? Is n1 a use of declared variable n2? Are n1 and n2
both uses of the same declared variable?
We'd like to introduce a new IdentExpr node to replace use of Name
within the AST, but that means those three cases need to be handled
differently. The first case needs to stay "n1 == n2", but the other
cases need to become "n1.Name() == n2" and "n1.Name() == n2.Name()",
respectively. ("n1.Name() == n2.Name()" also currently works for the
second case, but eventually we'll want to get rid of the Name.Name
method.)
This CL introduces helper functions SameSource and Uses to handle
these cases. It also introduces DeclaredBy, which is another somewhat
common case that the next CL introduces uses of.
Passes buildall w/ toolstash -cmp.
Updates #42990.
Change-Id: Ia816c124446e9067645d5820a8163f295968794f
Reviewed-on: https://go-review.googlesource.com/c/go/+/275305
Reviewed-by: Russ Cox <rsc@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
There are no language changes in Go 1.16, so document that.
For #40700.
Fixes#42976.
Change-Id: I80b0d2ce6cf550c00c0f026ee59ac9fbce6310be
Reviewed-on: https://go-review.googlesource.com/c/go/+/275117
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The only reason for the DeepCopyNode interface was to
allow the type syntaxes to avoid being constrained by
Left, Right etc. methods. Now those are gone, so the
general traversal methods they implement (doChildren, editChildren)
do the right thing for DeepCopy.
Passes buildall w/ toolstash -cmp.
Change-Id: I54672c011114a95efabff32dbcf02e6071f91b9e
Reviewed-on: https://go-review.googlesource.com/c/go/+/275379
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
deadcode is trying to walk the statements it can find,
but it can sweep in other nodes too. Stop doing that:
only walk known statements containing statements.
Otherwise, if we put panics in expression accessors that
shouldn't be used anymore, deadcode can trip them.
deadcode would be a good candidate to rewrite using
EditChildren, but that would certainly cause toolstash
changes, since deadcode is so ad-hoc about exactly
which parts of the function it looks at. For now just
remove the general traversal and leave as is.
Passes buildall w/ toolstash -cmp.
Change-Id: I06481eb87350905597600203c4fa724d55645b46
Reviewed-on: https://go-review.googlesource.com/c/go/+/275377
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
