Avoid interface calls, enable inlining, and store the rngSource close to the
Mutex to exploit better memory locality.

Also add a benchmark to properly measure the threadsafe nature of globalRand.

On a linux/amd64 VM:

name                       old time/op  new time/op  delta
Int63Threadsafe-4          36.4ns ±12%  20.6ns ±11%  -43.52%  (p=0.000 n=30+30)
Int63ThreadsafeParallel-4  79.3ns ± 5%  56.5ns ± 5%  -28.69%  (p=0.000 n=29+30)

Change-Id: I6ab912c1a1e9afc7bacd8e72c82d4d50d546a510
Reviewed-on: https://go-review.googlesource.com/c/go/+/191538Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This change adds an optional "producer" section that reports the source
language and compiler version. See
https://github.com/WebAssembly/tool-conventions/blob/master/ProducersSection.md.

It also removes the now redundant "go.version" section.

Fixes #33295.

Change-Id: Ib4c80528728caf9e524fbd3f26822cbbc8b05a75
Reviewed-on: https://go-review.googlesource.com/c/go/+/196804
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Agniva De Sarker <agniva.quicksilver@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

In the GOPATH section of the 'How To Write Go Code' document, it is
mentioned two times in the span of a few lines that one can set GOPATH
to a custom workspace path. The two paragraphs say basically the same
thing, and they both link to golang.org/wiki/SettingGOPATH, so I'm
quite sure the duplication is not intentional.

This change deletes the second occurrence.

Change-Id: I16f8bb8657041a23ed272eacf9adbc5637e8e34a
Reviewed-on: https://go-review.googlesource.com/c/go/+/197839Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

CL 197817 replaced a use of n.Rlist with n.Right in a Fprintf call,
but it left the corresponding format as %.v, which broke the
TestFormats test on the longtest builder.

Since with n.Right is custom to use %v (and not %.v), replace the
format with %v.

Fixes the longtest builder.

Change-Id: Icf5bf820a936c51e633c25ada1a71a1ffb6d28c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/197837
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This CL changes cmd/compile to use Node.Right instead of
Node.Rlist for OAS2FUNC/OAS2RECV/OAS2MAPR/OAS2DOTTYPE nodes.
Fixes #32293

Change-Id: I4c9d9100be2d98d15e016797f934f64d385f5faa
Reviewed-on: https://go-review.googlesource.com/c/go/+/197817
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

updates #21450

Change-Id: Ibffe0dadc1e1523c55cd5f5b8a69bc1c399a255d
GitHub-Last-Rev: 507f55508121a525de4d210e7ada1396ccaaf367
GitHub-Pull-Request: golang/go#33497
Reviewed-on: https://go-review.googlesource.com/c/go/+/189177
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This was missing from the original StructOf CL because I couldn't
think of a use for it. Now I can: even with types used entirely
by reflect, unexported fields can be set using UnsafeAddr.

Change-Id: I5e7e3d81d16e8817cdd69d85796ce33930ef523b
Reviewed-on: https://go-review.googlesource.com/c/go/+/85661
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

As mentioned in https://golang.org/issue/34062#issuecomment-529692313
src/cmd refers to older version of golang.org/x/tools.
Hence, not checking if multiple errors are used in the same fmt.Errorf.
Updating golang.org/x/tools version to latest in src/cmd.

Fixes #34062

Change-Id: I358dec2c3d3af2b19add766b8488b919109b81d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/196843
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

First, be consistent about declaring typ as &b.Func.Config.Types and
not &config.Types. Not particularly better, and it barely changes the
output, but we're more consistent now.

Second, remove a bit of duplication when handling the typ, auxint, and
aux variables.

Third and last, remove a stray canFail assignment; we ended up setting
that in add, not breakf, so it's not necessary to set it manually if we
don't use breakf.

Updates #33644.

Change-Id: I75999cb223a201969266fbfeae043599fa27fac5
Reviewed-on: https://go-review.googlesource.com/c/go/+/196803
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This CL updates the export data format to include column details when
writing out position data. cmd/compile is updated to generate and make
use of the new details, but go/internal/gcimporter only knows how to
read the data. It doesn't yet actually make use of it.

Experimentally across a wide range of packages, this increases export
data size by around 4%. However, it has no impact on binary size.
(Notably, it actually shrinks k8s.io/kubernetes/cmd/kubelet's binary
size by 24kB, but it's unclear to me why at this time.)

Updates #28259.

Change-Id: I351fb340839df8d3adced49b3757c4537fb91b3f
Reviewed-on: https://go-review.googlesource.com/c/go/+/196963
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Attributes with a namespace or a data- prefix are handled as if they
had no namespace/data- prefix.

There is also a special case, where attributes with a "xmlns" namespace
are always treated as containing URLs.

This could surprise users of the package, since this behaviour was not
documented anywhere, so this change adds some documentation for all
three cases.

Fixes #12648

Change-Id: If57a2ec49fec91a330fc04795726e8cffa9b75c0
Reviewed-on: https://go-review.googlesource.com/c/go/+/79895
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

The relative path element ".." is already rejected
by the checks for leading and trailing dots.

Fixes #27299

Change-Id: Ia8ab543c93288cdc0615abd6d22521d44bc56d72
Reviewed-on: https://go-review.googlesource.com/c/go/+/197720
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Removes TestTimeoutHandlerAndFlusher due to flakes on
one of the builders due to timing issues.

Perhaps later, we might need to bring it back when we've
figured out the timing issues.

Fixes #34573.

Change-Id: Ia88d4da31fb228296144dc31f9a4288167fb4a53
Reviewed-on: https://go-review.googlesource.com/c/go/+/197757
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Remove linker reading and processing of automs (no longer needed, now
that the compiler is emitting R_USETYPE relocations on functions). So
as to avoid changing the object file format, the object still contains
a count of automs, but this count is required to be zero.

Updates #34554.

Change-Id: I10230e191057c5c5705541eeb06f747d5f73c42d
Reviewed-on: https://go-review.googlesource.com/c/go/+/197500Reviewed-by: Jeremy Faller <jeremy@golang.org>

Don't write Autom records when writing a function to the object file;
we no longer need them in the linker for DWARF processing. So as to
keep the object file format unchanged, write out a zero-length list of
automs to the object, as opposed to removing all references.

Updates #34554.

Change-Id: I42a1d67207ea7114ae4f3a315cf37effba57f190
Reviewed-on: https://go-review.googlesource.com/c/go/+/197499Reviewed-by: Jeremy Faller <jeremy@golang.org>

Switch the linker over to use dummy R_USETYPE relocations on DWARF
subprogram DIEs as a means of insuring that DWARF types are created
for types of autotmp values used in live functions.

This change is part of a series intended to clean up handling of
autotmp types and remove use of autom's in the compiler and linker.

Updates #34554.

Change-Id: Ic74da6bd723ab7e4d8a16ad46e23228650d4b525
Reviewed-on: https://go-review.googlesource.com/c/go/+/197498
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

During DWARF processing, keep track of the go type symbols for types
directly or indirectly referenced by auto variables in a function,
and add a set of dummy R_USETYPE relocations to the function's DWARF
subprogram DIE symbol.

This change is not useful on its own, but is part of a series of
changes intended to clean up handling of autom's in the compiler
and linker.

Updates #34554.

Change-Id: I974afa9b7092aa5dba808f74e00aa931249d6fe9
Reviewed-on: https://go-review.googlesource.com/c/go/+/197497
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

ORUNESTR represents the special case of integer->string conversion. If
the integer is a constant, then the string is a constant too, so
evconst needs to perform constant folding here.

Passes toolstash-check.

Fixes #34563.

Change-Id: Ieab3d76794d8ce570106b6b707a4bcd725d156e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/197677
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Instead of returning an error, just panic: the function is
used only for debugging purposes anyway.

Change-Id: Ie81b2309daaf1efb9470992391534bce2141b3c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/196779Reviewed-by: David Chase <drchase@google.com>

In poset, all constants are always related to each other, so they
are part of the same DAG. Currently, it can be any of the DAGs in
the forest. Since we're about to start visiting that DAG for the
task of calculating bounds, make sure that it's conventionally
always the first, so that we don't need to search for it.

Change-Id: Ia7ca312b52336b4731b070d45cf0d768a0d6aeeb
Reviewed-on: https://go-review.googlesource.com/c/go/+/196599Reviewed-by: David Chase <drchase@google.com>

Also added a test to ensure that any interactions
between TimeoutHandler and Flusher result in the
correct status code and body, but also that we don't
get superfluous logs from stray writes as was seen
in the bug report.

Fixes #34439.

Change-Id: I4af62db256742326f9353f98a2fcb5f71d2a5fd9
Reviewed-on: https://go-review.googlesource.com/c/go/+/197659
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Currently we handle [...]T array literals by treating [...]T as
special "DDD array" types. However, these array literals are just
composite literal syntax, not a distinct Go type. Moreover,
representing them as Go types contributes to complexity in a number of
unrelated bits of code.

This CL changes OCOMPLIT typechecking to look for the [...]T syntax
and handle it specially, so we can remove DDD arrays.

Passes toolstash-check.

Change-Id: Ibbf701eac4caa7a321e2d10e256658fdfaa8a160
Reviewed-on: https://go-review.googlesource.com/c/go/+/197604
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Fixes #33977

Change-Id: I4b136788f08b08c53087af8d3cd56125e620b51b
Reviewed-on: https://go-review.googlesource.com/c/go/+/197602
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Typechecking slice literals, array literals, and array literals using
"..." notation all use very similar logic, but tie into the logic for
checking the OCOMPLIT node in slightly different ways.

By refactoring this function out into a separate helper, it makes it
easier to separate slice and array literals, and the subsequent CL
will further separate array literals that do use "..." notation from
those that do not.

Passes toolstash-check.

Change-Id: I4c572e0d9d08bcc86b5c224bd6f9e1c498726c19
Reviewed-on: https://go-review.googlesource.com/c/go/+/197603
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: I29e24c734e5e0041008771c805a0285aac3e02e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/196598Reviewed-by: David Chase <drchase@google.com>

prove wasn't able to detect induction variables that was bound
by another inducation variable. This happened because an indvar
is a Phi, and thus in case of a dependency, the loop bounding
condition looked as Phi < Phi. This triggered an existing
codepath that checked whether the upper bound was a Phi to
detect loop conditions written in reversed order respect to the
idiomatic way (eg: for i:=0; len(n)>i; i++).

To fix this, we call the indvar pattern matching on both operands
of the loop condition, so that the first operand that matches
will be treated as the indvar.

Updates #24660 (removes a boundcheck from Fannkuch)

Change-Id: Iade83d8deb54f14277ed3f2e37b190e1ed173d11
Reviewed-on: https://go-review.googlesource.com/c/go/+/195220Reviewed-by: David Chase <drchase@google.com>

This CL extracts the logic for pattern-matching an induction
variable into a separate function, in preparation for next CL
where we would need to call it multiple times.

No functional changes, passes toolstash -cmp.

Change-Id: Ic52391e6c1b2e72bae32a0f3f65dfea321caaf4f
Reviewed-on: https://go-review.googlesource.com/c/go/+/195737Reviewed-by: David Chase <drchase@google.com>

Removes TODO left by previous commit to appease toolstash.

Change-Id: I5c0bf25f21ba5c0abe3b1b2ed0b17c604717f39b
Reviewed-on: https://go-review.googlesource.com/c/go/+/197121Reviewed-by: Robert Griesemer <gri@golang.org>

Previously, we would recognize &(T{...}) expressions during type
checking, rewrite them into (*T){...}, and then do a lot of extra work
to make sure the user doesn't write (*T){...} themselves and
resynthesizing the OPTRLIT later on.

This CL simply handles &T{...} directly in the straight forward
manner, by changing OADDR directly to OPTRLIT when appropriate.

While here, match go/types's invalid composite literal type error
message.

Passes toolstash-check.

Change-Id: I902b14c7e2cd9fa93e6915dd58272d2352ba38f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/197120
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Now that OpSliceMake is called by runtime.makeslice callers,
prove can see and record the actual length and cap of each
slice being constructed.

This small patch is enough to remove 260 additional bound checks
from cmd+std.

Thanks to Martin Möhrmann for pointing me to CL141822 that
I had missed.

Updates #24660

Change-Id: I14556850f285392051f3f07d13b456b608b64eb9
Reviewed-on: https://go-review.googlesource.com/c/go/+/196784
Run-TryBot: Giovanni Bajo <rasky@develer.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

This allows for `LD 4(X5), X6' rather than `LD $4, X5, X6'. Similar for other
load and store instructions. It is worth noting that none of these are likely
to be used directly once the MOV pseudo-instructions are implemented.

Updates #27532

Change-Id: Ie043c2dedd2cdaceb258b27976cfb3f74aa1cc1d
Reviewed-on: https://go-review.googlesource.com/c/go/+/196842Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #34297

Change-Id: I4584a97d4562d7af0412d683ba1c206e3c1d9edb
Reviewed-on: https://go-review.googlesource.com/c/go/+/197539
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Add support for assembling control transfer instructions.

Based on the riscv-go port.

Updates #27532

Change-Id: I205d3ccd0a48deeaace0f20fca8516f382a83fae
Reviewed-on: https://go-review.googlesource.com/c/go/+/196841Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Add support for assembling AUIPC and LUI instructions.

Based on the riscv-go port.

Updates #27532

Change-Id: I178868b6dcc6fdc6b8527454569a3538ed50723e
Reviewed-on: https://go-review.googlesource.com/c/go/+/196840Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: If694ce529393b8ae9c6c55270665efc3a108a3b2
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/558778Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/197504Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

RFC 7230 is clear about headers with a space before the colon, like

X-Answer : 42

being invalid, but we've been accepting and normalizing them for compatibility
purposes since CL 5690059 in 2012.

On the client side, this is harmless and indeed most browsers behave the same
to this day. On the server side, this becomes a security issue when the
behavior doesn't match that of a reverse proxy sitting in front of the server.

For example, if a WAF accepts them without normalizing them, it might be
possible to bypass its filters, because the Go server would interpret the
header differently. Worse, if the reverse proxy coalesces requests onto a
single HTTP/1.1 connection to a Go server, the understanding of the request
boundaries can get out of sync between them, allowing an attacker to tack an
arbitrary method and path onto a request by other clients, including
authentication headers unknown to the attacker.

This was recently presented at multiple security conferences:
https://portswigger.net/blog/http-desync-attacks-request-smuggling-reborn

net/http servers already reject header keys with invalid characters.
Simply stop normalizing extra spaces in net/textproto, let it return them
unchanged like it does for other invalid headers, and let net/http enforce
RFC 7230, which is HTTP specific. This loses us normalization on the client
side, but there's no right answer on the client side anyway, and hiding the
issue sounds worse than letting the application decide.

Fixes CVE-2019-16276
Fixes #34540

Change-Id: I6d272de827e0870da85d93df770d6a0e161bbcf1
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/549719Reviewed-by: Brad Fitzpatrick <bradfitz@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/197503
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

If the parent context passed to WithCancel or WithTimeout
is a known context implementation (one created by this package),
we attach the child to the parent by editing data structures directly;
otherwise, for unknown parent implementations, we make a
goroutine that watches for the parent to finish and propagates
the cancellation.

A common problem with this scheme, before this CL, is that
users who write custom context implementations to manage
their value sets cause WithCancel/WithTimeout to start
goroutines that would have not been started before.

This CL changes the way we map a parent context back to the
underlying data structure. Instead of walking up through
known context implementations to reach the *cancelCtx,
we look up parent.Value(&cancelCtxKey) to return the
innermost *cancelCtx, which we use if it matches parent.Done().

This way, a custom context implementation wrapping a
*cancelCtx but not changing Done-ness (and not refusing
to return wrapped keys) will not require a goroutine anymore
in WithCancel/WithTimeout.

For #28728.

Change-Id: Idba2f435c81b19fe38d0dbf308458ca87c7381e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/196521Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This reverts CL 196837 (commit 78baea83).

Reason for revert: broke the mips64le build.

Change-Id: I531da60d098cb227659c9977a3d229474325b0a5
Reviewed-on: https://go-review.googlesource.com/c/go/+/197538
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

There are currently two edges in the lock cycle graph caused by
scavenge.lock: with sched.lock and mheap_.lock. These edges appear
because of the call to ready() and stack growths respectively.
Furthermore, there's already an invariant in the code wherein
mheap_.lock must be acquired before scavenge.lock, hence the cycle.

The fix to this is to bring scavenge.lock higher in the lock cycle
graph, such that sched.lock and mheap_.lock are only acquired once
scavenge.lock is already held.

To faciliate this change, we move scavenger waking outside of
gcSetTriggerRatio such that it doesn't have to happen with the heap
locked. Furthermore, we check scavenge generation numbers with the heap
locked by using gopark instead of goparkunlock, and specify a function
which aborts the park should there be any skew in generation count.

Fixes #34047.

Change-Id: I3519119214bac66375e2b1262b36ce376c820d12
Reviewed-on: https://go-review.googlesource.com/c/go/+/191977
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: I59446965b198767af60d617da29b5c2e457829ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/197477Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>