On systems that use kqueue, we always register descriptors for both
EVFILT_READ and EVFILT_WRITE. On at least FreeBSD and OpenBSD, when
the write end of a pipe is registered for EVFILT_READ and EVFILT_WRITE
events, and the read end of the pipe is closed, kqueue reports an
EVFILT_READ event with EV_EOF set, but does not report an EVFILT_WRITE
event. Since the write to the pipe is waiting for an EVFILT_WRITE
event, closing the read end of a pipe can cause the write end to hang
rather than attempt another write which will fail with EPIPE.

Fix this by treating EVFILT_READ with EV_EOF set as making both reads
and writes ready to proceed.

The real test for this is in CL 71770, which tests using various
timeouts with pipes.

Updates #22114

Change-Id: Ib23fbaaddbccd8eee77bdf18f27a7f0aa50e2742
Reviewed-on: https://go-review.googlesource.com/71973Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Fixes #22342.

Change-Id: Ic942162e98dce5749e381a31d58b0bf16c7d6f98
Reviewed-on: https://go-review.googlesource.com/72132
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Since inlining budget calculation is fixed in CL 70151
runtime.nextFreeFast is no longer inlineable on MIPS64x because
it does not support Ctz64 as intrinsic. Skip the test.

Updates #22239.

Change-Id: Id00d55628ddb4b48d27aebfa10377a896765d569
Reviewed-on: https://go-review.googlesource.com/72271
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This hack existed because cmd/go used to install (write) and then run
cmd/cgo in the same invocation, and writing and then running a program
is a no-no in modern multithreaded Unix programs (see #22315).

As of CL 68338, cmd/go no longer installs any programs that it then
tries to use. It never did this for any program other than cgo, and
CL 68338 removed that special case for cgo.

Now this special case, added for #3001 long ago, can be removed too.

Change-Id: I338f1f8665e9aca823e33ef7dda9d19f665e4281
Reviewed-on: https://go-review.googlesource.com/71571
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

build.go - commands and misc helpers
action.go - action graph construction
exec.go - action graph execution
gc.go - gc toolchain
gccgo.go - gccgo toolchain

Change-Id: I39b6e2490ac05334c2321e9ad88df694a6efa82f
Reviewed-on: https://go-review.googlesource.com/70671
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

It uses the build ID, which is soon to be internal to package work.
Luckily it is also only called from package work.

Change-Id: I5e6662cfe667bdc9190f086be733105ad65a3191
Reviewed-on: https://go-review.googlesource.com/70670
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Where GCC says "unrecognized command line option", clang says "unknown
argument". This distinction usually doesn't matter because the
compiler will also exit with a non-zero status, but clang 3.4
reportedly exits with a zero status after reporting an unknown argument.

Change-Id: Ieb69ea352a8de0cd4171a1c26708dfe523421cfa
Reviewed-on: https://go-review.googlesource.com/72151
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>

When traceviewer encounters a failure of json trace import
due to data error, onImportFail tried to access an error variable
which was not yet defined.

Change-Id: I431be03f179aafacaf1fd3c62a6337e8b5bd18fb
Reviewed-on: https://go-review.googlesource.com/71970Reviewed-by: Austin Clements <austin@google.com>

The test already contained logic to do this however it did not match
the error "cannot find 'ld'" which appears to be how gcc fails when
ld.gold is missing.

Fixes #22340.

Change-Id: I841248cc489b8fa72bc00a95000ad405f9ef8a4f
Reviewed-on: https://go-review.googlesource.com/72111
Run-TryBot: Michael Munday <mike.munday@ibm.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

A 1XX, 204, or 304 response may not include a response body according
to RFC 7230, section 3.3.3. If a buggy server returns a 204 or 304
response with a body that is chunked encoded, the invalid body is
currently made readable in the Response. This can lead to data races due
to the transport connection's read loop which does not wait for the body
EOF when the response status is 204 or 304.

The correct behavior is to ignore the body on a 204 or 304 response, and
treat the body data as the beginning of the next request on the
connection.

Updates #22330.

Change-Id: I89a457ceb783b6f66136d5bf9be0a9b0a04fa955
Reviewed-on: https://go-review.googlesource.com/71910Reviewed-by: Tom Bergan <tombergan@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Tom Bergan <tombergan@google.com>

For #22341.

Change-Id: I7e586c58075e4c835ef97701db2f38bdf7558521
Reviewed-on: https://go-review.googlesource.com/71974
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

https://golang.org/cl/71750 specifies iota values as indices,
thus making them independent from nested constant declarations.
This CL removes some of the comments in the examples that were
still referring to the old notion of iotas being incremented
and reset.

As an aside, please note that the spec still permits the use
of iota in a nested function (like before). Specifically, the
following cases are permitted by the spec (as before):

1) const _ = len([iota]int{})
2) const _ = unsafe.Sizeof(func(){ _ = iota })

For #15550.

Change-Id: I9e5fec75daf7b628b1e08d970512397e9c348923
Reviewed-on: https://go-review.googlesource.com/71912Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

racewalk's "foreach" function applies a function to all of a Node's
immediate children, but with a non-idiomatic signature.

This CL reworks it to recursively iterate over the entire subtree
rooted at Node and provides a way to short-circuit iteration.

Passes toolstash -cmp for std cmd with -race.

Change-Id: I738b73953d608709802c97945b7e0f4e4940d3f4
Reviewed-on: https://go-review.googlesource.com/71911
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: I094af156e7b8c31af3162d943a8c61268803ab89
Reviewed-on: https://go-review.googlesource.com/71830Reviewed-by: Gabriel Aszalos <gabriel.aszalos@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Gabriel Aszalos <gabriel.aszalos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

On modern Unix systems it is basically impossible for a multithreaded
program to open a binary for write, close it, and then fork+exec that
same binary. So don't write the binary if we're going to fork+exec it.

This fixes the ETXTBSY flakes.

Fixes #22220.
See also #22315.

Change-Id: I6be4802fa174726ef2a93d5b2f09f708da897cdb
Reviewed-on: https://go-review.googlesource.com/71570
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Issue #15550 is clearly an esoteric case but the spec was silent
about it and we had diverging implementations. By making `iota`
and index that is relative to the respective constant declaration,
nested const declarations won't affect outer values of `iota`.

cmd/compile and go/types already follow this semantics.

Fixes #15550.

Change-Id: If138189e3ea4373f8ba50ac6fb1d219b481f8698
Reviewed-on: https://go-review.googlesource.com/71750Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

golang.org/cl/37258 was committed to fix issue #16146.

This patch seemed intent to allow at most one dangling byte.  But, as
implemented, many more bytes may actually slip through.  This is because
the LZW layer creates a bufio.Reader which will itself consume data
beyond the end of the LZW stream, and this isn't accounted for anywhere.

This change means to avoid the allocation of the bufio.Reader by making
blockReader implement io.ByteReader.  Further, it adds a close() method
which detects extra data in the block sequence.  To avoid any
regressions with poorly encoded GIFs which may have worked accidentally,
there are no restrictions on how many extra bytes may exist in the final
full sub-block that contained LZW data.  If the end of the LZW stream
happened to align with the end of a sub-block, at most one more
sub-block with a length of 1 byte may exist before the block terminator.

This change aims to be at least as performant as the prior
implementation.  But the primary gain is avoiding the allocation of a
bufio.Reader per frame:

name      old time/op    new time/op    delta
Decode-8     276µs ± 0%     275µs ± 2%    ~     (p=0.690 n=5+5)

name      old speed      new speed      delta
Decode-8  55.9MB/s ± 0%  56.3MB/s ± 2%    ~     (p=0.690 n=5+5)

name      old alloc/op   new alloc/op   delta
Decode-8    49.2kB ± 0%    44.8kB ± 0%  -9.10%  (p=0.008 n=5+5)

name      old allocs/op  new allocs/op  delta
Decode-8       269 ± 0%       267 ± 0%  -0.74%  (p=0.008 n=5+5)

Change-Id: Iec4f9b895561ad52266313fbc73ec82c070c3349
Reviewed-on: https://go-review.googlesource.com/68350
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Nigel Tao <nigeltao@golang.org>

When building test binaries, we build one archive with all of the test
sources and a second archive with the generated test package main and
link them together. If the test sources are themselves in package main
and the test was compiled with non-default compiler flags, then both
archives will contain a go.cuinfo.producer.main symbol, leading to a
duplicate symbol failure.

This has been causing test build failures on darwin-arm-a1428ios,
darwin-arm64-a1549ios, linux-amd64-noopt, android-arm-wiko-fever, and
android-arm64-wiko-fever since CL 71430 added this symbol. This CL
should fix the build.

Change-Id: I69051c846e7c0d97395a865a361cae07f411f9ad
Reviewed-on: https://go-review.googlesource.com/71771
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

CL 70310 dropped TODO while moving code.
Add TODO back, so we do not forget.

Change-Id: I3599ac02743bd35fb9556fdc238e9c72cf7f718f
Reviewed-on: https://go-review.googlesource.com/71590Reviewed-by: David Crawshaw <crawshaw@golang.org>

Fixes #22258.

Change-Id: I43e68f1cf3163e1a041ebff2734ff2cb7943f695
Reviewed-on: https://go-review.googlesource.com/71431Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

No test because at present it is never called in a way that fails.
When #22114 is implemented, failure will be possible. Not including this
change in that work because this change is separable and clearly correct.

Updates #22114

Change-Id: I81eb9eec8800e8082d918c0e5fb71282f538267e
Reviewed-on: https://go-review.googlesource.com/71751
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Joe Tsai <joetsai@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

StructField.ByteSize is almost always unset; document that Type.Size()
is the place to look.

The dwarf package doesn't spend much effort teaching you DWARF, so I
don't know what level of handholding is appropriate. Still, no harm in a
little comment.

Closes #21093

Change-Id: I0ed8cad2fa18e10a47d264ff16c176d603d6033c
Reviewed-on: https://go-review.googlesource.com/71671
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Fixes #21800

Change-Id: I6c61d3543f28e9951b2a219b3c7298077b38f29e
Reviewed-on: https://go-review.googlesource.com/66210
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

This adds a whitelisted subset of compiler flags to the DW_AT_producer
DWARF attribute of each package compilation unit DIE. This is common
practice in DWARF and can help debuggers determine the quality of the
produced debugging information.

Fixes #22168.

Change-Id: I1b994ef2262aa9b88b68eb6e883695d1103acc58
Reviewed-on: https://go-review.googlesource.com/71430Reviewed-by: Ian Lance Taylor <iant@golang.org>

Currently mmap returns an unsafe.Pointer that encodes OS errors as
values less than 4096. In practice this is okay, but it borders on
being really unsafe: for example, the value has to be checked
immediately after return and if stack copying were ever to observe
such a value, it would panic. It's also not remotely idiomatic.

Fix this by making mmap return a separate pointer value and error,
like a normal Go function.

Updates #22218.

Change-Id: Iefd965095ffc82cc91118872753a5d39d785c3a6
Reviewed-on: https://go-review.googlesource.com/71270
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Set DW_AT_variable_parameter on DW_TAG_formal_parameters that are
actually return values. variable_parameter is supposed to indicate inout
parameters, but Go doesn't really have those, and DWARF doesn't have
explicit support for multiple return values. This seems to be the best
compromise, especially since the implementation of the two is very
similar -- both are stack slots.

Fixes #21100

Change-Id: Icebabc92b7b397e0aa00a7237478cce84ad1a670
Reviewed-on: https://go-review.googlesource.com/71670
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

Updates http2 to x/net/http2 git rev 1087133bc4a for:

  http2: reject DATA frame before HEADERS frame
  https://golang.org/cl/56770

  http2: respect peer's SETTINGS_MAX_HEADER_LIST_SIZE in ClientConn
  https://golang.org/cl/29243

  http2: reset client stream after processing response headers
  https://golang.org/cl/70510

Also updated TestRequestLimit_h2 as the behavior changed slightly due
to https://golang.org/cl/29243.

Fixes #13959
Fixes #20521
Fixes #21466

Change-Id: Iac659694f3a48b8bd485546a4f96a932e3056026
Reviewed-on: https://go-review.googlesource.com/71611
Run-TryBot: Tom Bergan <tombergan@google.com>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes Darwin 386 build. It turns out that the Darwin pthread_create
function saves the SSE registers, and therefore requires an aligned stack.
This worked before https://golang.org/cl/70530 because the stack sizes
were chosen to leave the stack aligned.

Change-Id: I911a9e8dcde4e41e595d5ef9b9a1ca733e154de6
Reviewed-on: https://go-review.googlesource.com/71432Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Fixes #13265.

Change-Id: I792eb4ee26bef8a56e279e23f9802cb39019e0d0
Reviewed-on: https://go-review.googlesource.com/34929Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #22292

Change-Id: I016e5f2b8624a6ebaf11a693a0f6d94d7b0d3f92
Reviewed-on: https://go-review.googlesource.com/71550Reviewed-by: Daniel Theophanes <kardianos@gmail.com>

More generally I'm concerned about these tests using
$GOROOT/src/cmd/go as scratch space, especially
combined wtih tg.parallel() - it's easy to believe some other
test might inadvertently also try to write x.exe about the
same time. This CL only solves the "didn't clean up x.exe"
problem and leaves for another day the "probably shouldn't
write to cmd/go at all" problem.

Fixes #22266.

Change-Id: I651534d70e2d360138e0373fb4a316081872550b
Reviewed-on: https://go-review.googlesource.com/71410
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Nowhere in the spec did we mention the import path for package
unsafe. Now we do.

Fixes #22308.

Change-Id: Ifd42c873188e898c597cdee4284e7a9d234a9282
Reviewed-on: https://go-review.googlesource.com/71373Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change-Id: I9d723e49bf2cabf97a09e29e46fd2c426845fd1d
Reviewed-on: https://go-review.googlesource.com/71470Reviewed-by: Ian Lance Taylor <iant@golang.org>

This reverts commit 897080d5.

Reason for revert: Fails to fix all the locking issues.

Updates #21117

Change-Id: I6fc9cb7897244d6e1af78c089a2bf383258ec049
Reviewed-on: https://go-review.googlesource.com/71450Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixed an error that occurred in atomic mode. cover adds a global
variable declaration that forces sync/atomic to be used. fixDirectives
was confused by this declaration since it has an invalid
position. These declarations are now skipped.

Fixes #22309

Change-Id: I84f5fec13ef847fca35ad49f7704fb93b60503e0
Reviewed-on: https://go-review.googlesource.com/71351
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Simplifies the switch statement in the isZeroValue function by merging
the case branches.

Change-Id: I5b27939b62808dadac0cef632567b17e0e2b9a1d
Reviewed-on: https://go-review.googlesource.com/71390
Run-TryBot: Gabriel Aszalos <gabriel.aszalos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

When an opening "{" of a block is missing and after advancing we
find a closing "}", it's likely better to assume the end of the
block. Fixed and removed TODO.

Change-Id: I20c9b4ecca798933a7cd4cbf21185bd4ca04f5f7
Reviewed-on: https://go-review.googlesource.com/71291Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change-Id: I2c2571b33603f0fd0ba5a79400da7b845d246b8c
Reviewed-on: https://go-review.googlesource.com/71290Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Current suffix check is based on instruction, which is not very
accurate. For example, "MOVW.S R1, R2" is valid, but
"MOVW.S $0xaaaaaaaa, R1" and "MOVW.P CPSR, R9" are not.

This patch fixes the above kinds of issues by checking suffix
based on []optab. And also more test cases are added.

fixes #20509

Change-Id: Ibad91be72c78eefa719412a83b4d44370d2202a8
Reviewed-on: https://go-review.googlesource.com/70910
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

CL 46037 and CL 46038 implemented termination of
locked OS threads when the goroutine exits.

However, this behavior leads to crashes of Go programs
using runtime.LockOSThread on Plan 9. This is notably
the case of the os/exec and net packages.

This change disables termination of locked OS threads
on Plan 9.

Updates #22227.

Change-Id: If9fa241bff1c0b68e7e9e321e06e5203b3923212
Reviewed-on: https://go-review.googlesource.com/71230Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>