The code writes text sections twice, one with Codeblk, one with
Datblk. The second write shouldn't be there.
May fix#38898.
Change-Id: I4ec70294059ec9aa0fc4cc69a3cd824f5843287b
Reviewed-on: https://go-review.googlesource.com/c/go/+/232661
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reject base 128 encoded integers that aren't using minimal encoding,
specifically if the leading octet of an encoded integer is 0x80. This
only affects parsing of tags and OIDs, both of which expect this
encoding (see X.690 8.1.2.4.2 and 8.19.2).
Fixes#36881
Change-Id: I969cf48ac1fba7e56bac334672806a0784d3e123
GitHub-Last-Rev: fefc03d202
GitHub-Pull-Request: golang/go#38281
Reviewed-on: https://go-review.googlesource.com/c/go/+/227320
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The previous behavior directly contradicted the docs that have been in
place for years:
To unmarshal a JSON array into a slice, Unmarshal resets the
slice length to zero and then appends each element to the slice.
We could use reflect.New to create a new element and reflect.Append to
then append it to the destination slice, but benchmarks have shown that
reflect.Append is very slow compared to the code that manually grows a
slice in this file.
Instead, if we're decoding into an element that came from the original
backing array, zero it before decoding into it. We're going to be using
the CodeDecoder benchmark, as it has a slice of struct pointers that's
decoded very often.
Note that we still reuse existing values from arrays being decoded into,
as the documentation agrees with the existing implementation in that
case:
To unmarshal a JSON array into a Go array, Unmarshal decodes
JSON array elements into corresponding Go array elements.
The numbers with the benchmark as-is might seem catastrophic, but that's
only because the benchmark is decoding into the same variable over and
over again. Since the old decoder was happy to reuse slice elements, it
would save a lot of allocations by not having to zero and re-allocate
said elements:
name old time/op new time/op delta
CodeDecoder-8 10.4ms ± 1% 10.9ms ± 1% +4.41% (p=0.000 n=10+10)
name old speed new speed delta
CodeDecoder-8 186MB/s ± 1% 178MB/s ± 1% -4.23% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
CodeDecoder-8 2.19MB ± 0% 3.59MB ± 0% +64.09% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
CodeDecoder-8 76.8k ± 0% 92.7k ± 0% +20.71% (p=0.000 n=10+10)
We can prove this by moving 'var r codeResponse' into the loop, so that
the benchmark no longer reuses the destination pointer. And sure enough,
we no longer see the slow-down caused by the extra allocations:
name old time/op new time/op delta
CodeDecoder-8 10.9ms ± 0% 10.9ms ± 1% -0.37% (p=0.043 n=10+10)
name old speed new speed delta
CodeDecoder-8 177MB/s ± 0% 178MB/s ± 1% +0.37% (p=0.041 n=10+10)
name old alloc/op new alloc/op delta
CodeDecoder-8 3.59MB ± 0% 3.59MB ± 0% ~ (p=0.780 n=10+10)
name old allocs/op new allocs/op delta
CodeDecoder-8 92.7k ± 0% 92.7k ± 0% ~ (all equal)
I believe that it's useful to leave the benchmarks as they are now,
because the decoder does reuse memory in some cases. For example,
existing map elements are reused. However, subtle changes like this one
need to be benchmarked carefully.
Finally, add a couple of tests involving both a slice and an array of
structs.
Fixes#21092.
Change-Id: I8b1194f25e723a31abd146fbfe9428ac10c1389d
Reviewed-on: https://go-review.googlesource.com/c/go/+/191783
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The `yield := osyield` line doesn't serve any purpose, it's committed in `2015`, time to delete that line:)
Change-Id: I382d4d32cf320f054f011f3b6684c868cbcb0ff2
GitHub-Last-Rev: 7a0aa25e55
GitHub-Pull-Request: golang/go#36078
Reviewed-on: https://go-review.googlesource.com/c/go/+/210837
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit moves the isSelect bool below the ticket uint32. The
boolean was consuming 8 bytes of the struct. The uint32 was also
consuming 8 bytes, so we can pack isSelect below the uint32 and save 8
bytes. This reduces the sudog struct from 96 bytes to 88 bytes.
Change-Id: If555cdaf2f5eaa125e2590fc4d113dbc99750738
GitHub-Last-Rev: d63b4e086b
GitHub-Pull-Request: golang/go#36552
Reviewed-on: https://go-review.googlesource.com/c/go/+/214677
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Change-Id: I493bb7e5e9a9e1752236dea1e032b317da7f67f1
Reviewed-on: https://go-review.googlesource.com/c/go/+/211560
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This CL sets positions for errors from cals to load within the load
call itself, similar to how the rest of the code in pkg.go sets
positions right after the error is set on the package.
This allows the code to ensure that we only add positions either for
ImportPathErrors, or if an error was passed into load, and was set
using setLoadPackageDataError. (Though I'm wondering if the call
to setLoadPackageDataError should be done before the call to load).
Fixes#38034
Change-Id: I0748866933b4c1a329954b4b96640bef702a4644
Reviewed-on: https://go-review.googlesource.com/c/go/+/228784
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Being lenient on those has caused enough security issues.
Spun out of CL 231419.
Fixes#38889
Change-Id: Idd3bc6adc22e08a30b3dabb146ce78d4105684cd
Reviewed-on: https://go-review.googlesource.com/c/go/+/232277
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Before going around making changes, surface the current behavior in the
docs as a starting point. No behavior changes.
Change-Id: If8096cedbba7eda37694dbb7f438046d590c3bcc
Reviewed-on: https://go-review.googlesource.com/c/go/+/231377
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
This is a security hardening measure against HTTP request smuggling.
Thank you to ZeddYu for reporting this issue.
We weren't parsing things correctly anyway, allowing "identity" to be
combined with "chunked", and ignoring any Transfer-Encoding header past
the first. This is a delicate security surface that already broke
before, just be strict and don't add complexity to support cases not
observed in the wild (nginx removed "identity" support [1] and multiple
TE header support [2]) and removed by RFC 7230 (see page 81).
It'd probably be good to also drop support for anything other than
"chunked" in outbound TE headers, as "identity" is not a thing anymore,
and we are probably off-spec for anything other than "chunked", but it
should not be a security concern, so leaving it for now. See #38867.
[1]: https://hg.nginx.org/nginx/rev/fe5976aae0e3
[2]: https://hg.nginx.org/nginx/rev/aca005d232ff
Change-Id: If17d0827f9c6167a0b19a158e2bc5844ec803288
Reviewed-on: https://go-review.googlesource.com/c/go/+/231418
Reviewed-by: Katie Hockman <katie@golang.org>
Clients have to reject any HelloRetryRequest message that doesn't lead
to a change in the ClientHello. Instead, we were rejecting any HRR that
didn't select an alternative group, even if it sent a cookie, which
would change the CH.
The good news is that I know of no TLS servers that use or need HRRs
exclusively for cookies (which are mostly useful in DTLS as a way to
verify the source address). The bad news is that we poisoned the
ecosystem as Go 1.12 to 1.14 will reject such HRRs. Oops, hopefully no
one needed this.
No tests because neither Go nor s_server support cookies. This would
presumably get covered once we integrate BoGo.
Fixes#30149
Change-Id: I760fb1ded81148ac3096cf201cbc1e941374b83d
Reviewed-on: https://go-review.googlesource.com/c/go/+/231039
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
Following CL 208126, do the same for MIPS.
Change-Id: I95f8fc99a234524119a4d29c7695676dc0ea1025
Reviewed-on: https://go-review.googlesource.com/c/go/+/208217
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
On some architectures, for async preemption the injected call
needs to clobber a register (usually REGTMP) in order to return
to the preempted function. As a consequence, the PC ranges where
REGTMP is live are not preemptible.
The uses of REGTMP are usually generated by the assembler, where
it needs to load or materialize a large constant or offset that
doesn't fit into the instruction. In those cases, REGTMP is not
live at the start of the instruction sequence. Instead of giving
up preemption in those cases, we could preempt it and restart the
sequence when resuming the execution. Basically, this is like
reissuing an interrupted instruction, except that here the
"instruction" is a Prog that consists of multiple machine
instructions. For this to work, we need to generate PC data to
mark the start of the Prog.
Currently this is only done for ARM64.
TODO: the split-stack function prologue is currently not async
preemptible. We could use this mechanism, preempt it and restart
at the function entry.
Change-Id: I37cb282f8e606e7ab6f67b3edfdc6063097b4bd1
Reviewed-on: https://go-review.googlesource.com/c/go/+/208126
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
There is a range of numbers lower than 0x7fff_ffff_ffff_ffff which
cannot be represented by a 64 bit float. We set that to the correct
limit beyond which conversions can happen properly.
It appears that the negative bound check can indeed by correctly handled
by I64TruncF64S. But we use the same limit for consistency.
Fixes#38839
Change-Id: Ib783a22cb331fba7e6955459f41c67f9ceb53461
Reviewed-on: https://go-review.googlesource.com/c/go/+/231837
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Record the caller when Cleanup is called to report it with t.Log
instead of unhelpful line in testing.go.
Fixes#38800
Change-Id: I3136f5d92a0e5a48f8b32a2e13b2521bc91d72d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/232237
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The {AND,OR,XOR}const ops can only take an int32 as an argument.
Make sure that when rewriting a BTx op to one of these, the result
has no high-order bits.
Fixes#38746
Change-Id: Ia7c5f76952329f60974bc033c29a5433610f3b28
Reviewed-on: https://go-review.googlesource.com/c/go/+/231977
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Replaced almost every use of Bytes with FillBytes.
Note that the approved proposal was for
func (*Int) FillBytes(buf []byte)
while this implements
func (*Int) FillBytes(buf []byte) []byte
because the latter was far nicer to use in all callsites.
Fixes#35833
Change-Id: Ia912df123e5d79b763845312ea3d9a8051343c0a
Reviewed-on: https://go-review.googlesource.com/c/go/+/230397
Reviewed-by: Robert Griesemer <gri@golang.org>
The Go 1.15 code freeze has just started. This is the time to update
all golang.org/x/... module versions that contribute packages to the
std and cmd modules in the standard library to latest master versions.
Those versions have already gone through code review, and now they
will undergo additional testing during the freeze period.
If there are new issues in these dependencies discovered, we have
the freeze period to deal with that. By the end of the freeze period,
we will have confidence that the Go 1.15 release and the dependency
versions it has selected are robust.
If one of the Go 1.15.x minor releases requires changing code in one of
the vendored packages, we'll be able to do so on top of the versions
that are selected here, and not be forced to use versions that came
from different time periods, or try to jump across multiple untested
versions in a minor release.
The dependency versions that are selected in this commit are:
github.com/google/pprof v0.0.0-20200229191704-1ebb73c60ed3
github.com/ianlancetaylor/demangle v0.0.0-20200414190113-039b1ae3a340
golang.org/x/arch v0.0.0-20200312215426-ff8b605520f4
golang.org/x/crypto v0.0.0-20200429183012-4b2356b1ed79
golang.org/x/mod v0.2.1-0.20200429172858-859b3ef565e2
golang.org/x/net v0.0.0-20200501053045-e0ff5e5a1de5
golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3
golang.org/x/text v0.3.3-0.20200430171850-afb9336c4530
golang.org/x/tools v0.0.0-20200504152539-33427f1b0364
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543
github.com/ianlancetaylor/demangle is considered in scope and updated.
github.com/google/pprof is out of scope and was not updated.
For #36905.
Change-Id: Icb6996eb0df11f16edd9a42e04434012c0336354
Reviewed-on: https://go-review.googlesource.com/c/go/+/231657
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, Value.Addr collapses flagRO, which is a combination of
flagEmbedRO and flagStickyRO, to flagStickyRO. This causes exported
fields of unexported anonymous field from Value.Addr.Elem read only.
This commit fix this by keeping all bits of flagRO from origin
value in Value.Addr. This should be safe due to following reasons:
* Result of Value.Addr is not CanSet because of it is not CanAddr
but not flagRO.
* Addr.Elem get same flagRO as origin, so it should behave same as
origin in CanSet.
Fixes#32772.
Change-Id: I79e086628c0fb6569a50ce63f3b95916f997eda1
GitHub-Last-Rev: 78e280e6d0
GitHub-Pull-Request: golang/go#32787
Reviewed-on: https://go-review.googlesource.com/c/go/+/183937
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
QueryPattern will now look up the current version of a module (if any)
before invoking queryProxy. This changes the interpretation of some
patterns (like "upgrade") and avoids the need to download earlier
versions for earlier versions when the current version is
+incompatible.
Fixes#37574
Change-Id: I4089d6099236493df13a7f88a252b5e5e556d383
Reviewed-on: https://go-review.googlesource.com/c/go/+/231599
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Introduces a few casts, mostly to fix rules that mix int64 and int32
off1 and off2.
Passes
GOARCH=arm64 gotip build -toolexec 'toolstash -cmp' -a std
Change-Id: I1ec75211f3bb8e521dcc5217cf29ab0655a84d79
Reviewed-on: https://go-review.googlesource.com/c/go/+/230840
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CL 208617 introduced syscall.utf16PtrToString and
internal/syscall/windows.UTF16PtrToString functions.
Original version of CL 208617 did not include syscall.utf16PtrToString
and internal/syscall/windows.UTF16PtrToString max parameter. The
parameter was added by Brad at the request of Ian. Ian said:
"In some cases it seems at least possible that the null terminator is
not present. I think it would be safer if we passed a maximum length
here."
The syscall.utf16PtrToString and
internal/syscall/windows.UTF16PtrToString function are designed to work
with only null terminated strings. So max parameter is superfluous.
This change removes max parameter.
Updates #34972
Change-Id: Ifea65dbd86bca8a08353579c6b9636c6f963d165
Reviewed-on: https://go-review.googlesource.com/c/go/+/228858
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
When forwarding a request, a SingleHostReverseProxy appends the
request's path to the target URL's path. However, if certain path
elements are encoded, (such as %2F for slash in either the request or
target path), simply joining the URL.Path elements is not sufficient,
since the field holds the decoded path.
Since 87a605, the RawPath field was added which holds a decoding
hint for the URL. When joining URL paths, this decoding hint needs
to be taken into consideration.
As an example, if the target URL.Path is /a/b, and URL.RawPath
is /a%2Fb, joining the path with /c should result in /a/b/c
in URL.Path, and /a%2Fb/c in RawPath.
The added joinURLPath function combines the two URL's Paths,
while taking into account escaping, and replaces the previously used
singleJoiningSlash in NewSingleHostReverseProxy.
Fixes#35908
Change-Id: I45886aee548431fe4031883ab1629a41e35f1727
GitHub-Last-Rev: 7be6b8d421
GitHub-Pull-Request: golang/go#36378
Reviewed-on: https://go-review.googlesource.com/c/go/+/213257
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This makes the intent clearer, allows for another ellipsis and will aid
in future rewriting. While here, document boolean loads to explain register
contents.
Change-Id: I933db2813826d88819366191fbbea8fcee5e4dda
Reviewed-on: https://go-review.googlesource.com/c/go/+/230120
Reviewed-by: Keith Randall <khr@golang.org>
Ctty was always handled as a child descriptor, but in some cases
passing a parent descriptor would also work. This depended on
unpredictable details of the implementation. Reject those cases to
avoid confusion.
Also reject setting both Setctty and Foreground, as they use Ctty
in incompatible ways. It's unlikely that any programs set both fields,
as they don't make sense together.
Fixes#29458
Change-Id: Ieba2d625711fd4b82c8e65e1feed02fd1fb25e6d
Reviewed-on: https://go-review.googlesource.com/c/go/+/231638
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Normalization of number prefixes and exponents was added in CL 160184
directly in cmd/gofmt. The same behavior change needs to be applied in
the go/format package. This is done by moving the normalization code
into go/printer, behind a new StdFormat mode, which is then re-used
by both cmd/gofmt and go/format.
Note that formatting of Go source code changes over time, so the exact
byte output produced by go/printer may change between versions of Go
when using StdFormat mode. What is guaranteed is that the new formatting
is equivalent Go code.
Clients looking to format Go code with standard formatting consistent
with cmd/gofmt and go/format would need to start using this flag, but
a better alternative is to use the go/format package instead.
Benchstat numbers on go test go/printer -bench=BenchmarkPrint:
name old time/op new time/op delta
Print-8 4.56ms ± 1% 4.57ms ± 0% ~ (p=0.700 n=3+3)
name old alloc/op new alloc/op delta
Print-8 467kB ± 0% 467kB ± 0% ~ (p=1.000 n=3+3)
name old allocs/op new allocs/op delta
Print-8 17.2k ± 0% 17.2k ± 0% ~ (all equal)
That benchmark data doesn't contain any numbers that need to be
normalized. More work needs to be performed when formatting Go code
with numbers, but it is unavoidable to produce standard formatting.
Fixes#37476.
For #37453.
Change-Id: If50bde4035c3ee6e6ff0ece5691f6d3566ffe8d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/231461
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Adding the usage of PCALIGN directive for arm64, and updating some
details on using some directives defined in the textflag.h file.
Change-Id: I43d363e3337939bab69b856831caf06803a292d2
Reviewed-on: https://go-review.googlesource.com/c/go/+/227801
Reviewed-by: Cherry Zhang <cherryyz@google.com>
CL 231397 is submitted too fast... Expand the comment to make it
a little clearer.
Change-Id: Ica9737aa7b51f97320bab74457388dcab8188370
Reviewed-on: https://go-review.googlesource.com/c/go/+/231597
Reviewed-by: Austin Clements <austin@google.com>
This commit adds a new option to the x86 assembler. If the
GOAMD64 environment variable is set to alignedjumps (the
default) and we're doing a 64 bit build, the assembler will
make sure that neither stand alone nor macro-fused jumps will
end on or cross 32 byte boundaries. To achieve this, functions
are aligned on 32 byte boundaries, rather than 16 bytes, and
jump instructions are padded to ensure that they do not
cross or end on 32 byte boundaries. Jumps are padded
by adding a NOP instruction of the appropriate length before
the jump.
The commit is likely to result in larger binary sizes when
GOAMD64=alignedjumps. On the binaries tested so far, an
increase of between 1.4% and 1.5% has been observed.
Updates #35881
Co-authored-by: David Chase <drchase@google.com>
Change-Id: Ief0722300bc3f987098e4fd92b22b14ad6281d91
Reviewed-on: https://go-review.googlesource.com/c/go/+/219357
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
A symbol being reachable doesn't imply its type descriptor is
needed. Don't mark it.
If the type is converted to interface somewhere in the program,
there will be an explicit use of the type descriptor, which
will make it marked.
A println("hello") program before and after
-rwxr-xr-x 1 cherryyz primarygroup 1259824 Apr 30 23:00 hello
-rwxr-xr-x 1 cherryyz primarygroup 1169680 Apr 30 23:10 hello
Updates #38782.
Updates #6853.
Change-Id: I88884c126ce75ba073f1ba059c4b892c87d2ac96
Reviewed-on: https://go-review.googlesource.com/c/go/+/231397
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
(Reland of golang.org/cl/33677.)
This CL adds a UsesCgo config setting to go/types to specify that the
_cgo_gotypes.go file generated by cmd/cgo has been provided as a
source file. The type checker then internally resolves C.bar qualified
identifiers to _Cfoo_bar as appropriate.
It also adds support to srcimporter to automatically run cgo.
Unfortunately, this functionality is not compatible with overriding
OpenFile, because cmd/cgo and gcc will directly open files.
Updates #16623.
Updates #35721.
Change-Id: Ib179d55c8c589916f98ceeae0b9a3e746157253a
Reviewed-on: https://go-review.googlesource.com/c/go/+/231459
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
