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>
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>
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>
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>
Put each node in charge of its EditChildren implementation.
This removes the final generic use of Left, SetLeft, Right, SetRight,
and so on in package ir.
Passes buildall w/ toolstash -cmp.
Change-Id: I9821cc20f5b91cc9b44eb1f386cc82f20cd6770c
Reviewed-on: https://go-review.googlesource.com/c/go/+/275376
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Put each node in charge of its DoChildren implementation.
This removes a generic use of Left, Right, and so on
in func DoChildren, heading toward removing those even from
being used in package ir.
Passes buildall w/ toolstash -cmp.
Change-Id: Ibdf56f36801217cf24549e063da0078c1820a56b
Reviewed-on: https://go-review.googlesource.com/c/go/+/275375
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Put each node in charge of making copies of its own slices.
This removes a generic use of Body, SetBody, and so on
in func Copy, heading toward removing those even from
being used in package ir.
Passes buildall w/ toolstash -cmp.
Change-Id: I249b7fe54cf72e9d2f0467b10f3f257abf9b29b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/275374
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This CL rephrases the general inlining rewriter in terms of ir.EditChildren.
It is the final part of the code that was processing arbitrary nodes using
Left, SetLeft, and so on. After this CL, there should be none left except
for the implementations of DoChildren and EditChildren, which fall next.
Passes buildall w/ toolstash -cmp.
Change-Id: I9c36053360cd040710716f0b39397a80114be713
Reviewed-on: https://go-review.googlesource.com/c/go/+/275373
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This CL converts all the generic searching traversal to use ir.Find
instead of relying on direct access to Left, Right, and so on.
Passes buildall w/ toolstash -cmp.
Change-Id: I4d951aef630c00bf333f24be79565cc564694d04
Reviewed-on: https://go-review.googlesource.com/c/go/+/275372
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This CL introduces the general visitor functionality that will replace
the Left, SetLeft, Right, SetRight, etc methods in the Node interface.
For now, the CL defines the functionality in terms of those methods,
but eventually the Nodes themselves will implement DoChildren
and EditChildren and be relieved of implementing Left, SetLeft, and so on.
The CL also updates Inspect (which moved to visit.go) and DeepCopy
to use the new functionality.
The Find helper is not used in this CL but will be used in a future one.
Passes buildall w/ toolstash -cmp.
Change-Id: Id0eea654a884ab3ea25f48bd8bdd71712b5dcb44
Reviewed-on: https://go-review.googlesource.com/c/go/+/275311
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Now inlcopy and ir.DeepCopy are semantically the same,
so drop the inlcopy implementation.
Passes buildall w/ toolstash -cmp.
Change-Id: Id2abb39a412a8e57167a29be5ecf76e990dc9d3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/275310
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
DeepCopy is not called DeepSepCopy, so it should use Copy, not SepCopy.
Also, the old gc.treecopy, which became ir.DeepCopy, only copied
the Left, Right, and List fields - not Init, Rlist, Body - and I didn't
notice when I moved it over. A general utility function should of
course copy the whole node, so do that.
Finally, the semantics of Copy should not depend on whether a
particular child node is held directly in a field or in a slice,
so make Copy duplicate the slice backing arrays as well.
(Logically, those backing arrays are part of the node storage.)
Passes buildall w/ toolstash -cmp.
Change-Id: I18fbe3f2b40078f566ed6370684d5585052b36a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/275309
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The upcoming general iterators will process nodes in
source code order, meaning that the "then" block comes
before the "else" block. But for an if node, "then" is Body
while "else" is Rlist, and the inliner processes Rlist first.
The order of processing changes the order of inlining decisions,
which can affect which functions are inlined, but in general
won't affect much. (It's not like we know that we should prefer
to inline functions in else bodies over then bodies.)
Swapping these is not safe for toolstash -cmp.
Doing it in a separate CL lets the upcoming CLs all be toolstash-safe.
Change-Id: Id16172849239b0564930d2bbff1260ad6d03d5ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/275308
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This CL consolidates and cleans up fmt.go's logic for skipping past
Nodes introduced during typechecking. This allows eliminating SetOrig
on ConvExpr and Name. Also changes ConstExpr.SetOrig to a panic for
good measure.
The only remaining SetOrig uses now are for rewriting multi-value
"f(g())" calls and "return g()" statements, and type-checking
composite literals. It should be possible to eliminate both of those
as well.
Passes buildall w/ toolstash -cmp.
Change-Id: I478aea1a17dfb7a784293b930bf9081637eb2d7a
Reviewed-on: https://go-review.googlesource.com/c/go/+/275179
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
It's useful to have quick access to the types.Field that a given
selector or method value expression refer to. Previously we abused Opt
for this, but couldn't do that for OCALLPART because escape analysis
uses Opt.
Now that we have more flexibility, we can simply add additional
pointer fields for this. This also allows getting rid of an unneeded
ONAME node for OCALLPART.
Passes buildall w/ toolstash -cmp.
Change-Id: I980d7bdb19abfd0b6f58a232876861b88dee1e47
Reviewed-on: https://go-review.googlesource.com/c/go/+/275034
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
The next CL adds ConstExpr, which is a more memory efficient
representation for constant expressions than Name. However, currently
a bunch of Val helper methods are defined on Name. This CL changes
them into standalone functions that work with any Node.Val
implementation.
There's also an existing standalone function named Int64Val, which
takes a Type argument to specify what type of integer is expected. So
to avoid collisions, this CL renames it to IntVal.
Passes buildall w/ toolstash -cmp.
[git-generate]
cd src/cmd/compile/internal/ir
rf 'mv Int64Val IntVal'
sed -i -E -e 's/\(n \*Name\) (CanInt64|((I|Ui)nt64|Bool|String)Val)\(/\1(n Node/' name.go
cd ../gc
rf '
ex {
import "cmd/compile/internal/ir"
var n ir.Node
n.CanInt64() -> ir.CanInt64(n)
n.Int64Val() -> ir.Int64Val(n)
n.Uint64Val() -> ir.Uint64Val(n)
n.BoolVal() -> ir.BoolVal(n)
n.StringVal() -> ir.StringVal(n)
}
'
cd ../ir
rf '
mv CanInt64 Int64Val Uint64Val BoolVal StringVal val.go
rm Node.CanInt64 Node.Int64Val Node.Uint64Val Node.BoolVal Node.StringVal
'
Change-Id: I003140bda1690d770fd608bdd087e6d4ff00fb1f
Reviewed-on: https://go-review.googlesource.com/c/go/+/275032
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Recreated manually to push below some CLs it depended on.
Change-Id: I1b3316fcdce39cbb33e5cbb471f5cd1cd2efc1f5
Reviewed-on: https://go-review.googlesource.com/c/go/+/274599
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This CL improves handling of OCONVNOP nodes during ssa generation,
so it is not toolstash safe.
An OCONVNOP wrapper is necessary for the "for" condition of
certain compiled range loops, and the boolean evaluator was
not looking through them properly, generating unnecessary
temporaries. That change saved 8k of the (13 MB) go binary.
The other changes just streamline the handling of OCONVNOP
to be more like what OSTMTEXPR will be like. They have no
effect on output size but do tweak the ssa graph a little, which
causes different register decisions and therefore different output.
Change-Id: I9e1dcd413b60944e21554c3e3f2bdc9adcee7634
Reviewed-on: https://go-review.googlesource.com/c/go/+/274598
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The check for blank in okAs is redundant with what its callers already
done, so just inline the conversion in callers side instead.
Passes toolstash-check.
Change-Id: I606105e2d2cf8e80214722a13c3101c464d20d82
Reviewed-on: https://go-review.googlesource.com/c/go/+/274793
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Noticed the typ field was duplicated, since it is also in miniExpr inside Name.
Also clarified the comments for Func, now that it is actually the ODCLFUNC node.
Change-Id: Ia483a0ad34bb409cd92c43d4ae0a6852f9e4f644
Reviewed-on: https://go-review.googlesource.com/c/go/+/274619
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dan Scales <danscales@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
For statements like goto that don't need an init, use an
explicit block statement instead of forcing them to have one.
There is also one call to addinit that is being replaced with
a block. That call is the source of much of my confusion
regarding init statements: walkstmt calls addinit on a statement,
whereas all the other uses of addinit are on expressions.
After this CL, they're all expressions.
Passes buildall w/ toolstash -cmp.
Change-Id: Ifdef9d318c236dc1a7567f9e9ef4a6bedd3fe81f
Reviewed-on: https://go-review.googlesource.com/c/go/+/274597
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Not toolstash -cmp safe, so split into its own CL.
Change-Id: I523227514a95e19c9afe17556d754a03164bce76
Reviewed-on: https://go-review.googlesource.com/c/go/+/274595
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
OEMPTY is an empty *statement*, but it confusingly
gets handled as an expression in a few places.
More confusingly, OEMPTY often has an init list,
making it not empty at all. Replace uses and analysis
of OEMPTY with OBLOCK instead.
Passes buildall w/ toolstash -cmp.
Change-Id: I8d4fcef151e4f441fa19b1b96da5272d778131d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/274594
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
It turned out that "go get" was using the network to look up
https://github.com?go-get=1 while resolving github.com/google/go-cmp,
and that is not the fastest page to load.
Stop that lookup by adjusting the path prefixes in the vcs table.
It also turned out that "go get" was using the network to look up
https://rsc.io?go-get=1 while resolving https://rsc.io/nonexist.svn.
That's a bit more defensible maybe, since rsc.io is not a known VCS host.
But for tests we really want to avoid the network entirely, so this CL
adds a special case in repoRootFromVCSPaths that returns a hard error
for plain "rsc.io" instead of doing the web fetch.
To keep us honest in the future, I added two automatically-set env
variables TESTGONETWORK=panic and TESTGOVCS=panic.
These cause the go command to panic rather than make a network request
or invoke a VCS command.
go test -short cmd/go now passes with these checks.
This reduced the time spent in go test -short cmd/go on my
Google workstation from 154s to 30s. (Yay network firewalls.)
Change-Id: I49207fca7f901fa011765fb984dc9cec8b691f11
Reviewed-on: https://go-review.googlesource.com/c/go/+/274441
Trust: Russ Cox <rsc@golang.org>
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
