Ignore memory access on g0/gsignal.
See the issue for context and explanation.
Fixes #8627.

LGTM=khr
R=golang-codereviews, mdempsky, khr
CC=golang-codereviews, rsc
https://golang.org/cl/137070043

Code to bring goroutines to a gc safepoint one at a time,
do some work such as scanning, and restart the
goroutine, and then move on to the next goroutine.
Currently this code does not do much useful work
but this infrastructure will be critical to future
concurrent GC work.

Fixed comments reviewers.

LGTM=rsc
R=golang-codereviews, rsc, dvyukov
CC=golang-codereviews
https://golang.org/cl/131580043

LGTM=rsc
R=golang-codereviews, rsc, khr
CC=golang-codereviews
https://golang.org/cl/139900043

LGTM=alex.brainman, iant
R=golang-codereviews, alex.brainman, iant
CC=dvyukov, golang-codereviews, khr, r
https://golang.org/cl/139070043

This gives them correct types in Go and also makes it
possible to use them to run Go code on an m stack.

LGTM=iant
R=golang-codereviews, dave, iant
CC=dvyukov, golang-codereviews, khr, r
https://golang.org/cl/137970044

They were in proc.c mainly because there was no portable
traceback source file. As part of converting them to Go,
move to traceback.go.

In order to get access to the PC of _rt0_go,
rename to runtime.rt0_go.

LGTM=r
R=golang-codereviews, r
CC=dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/139110043

This removes the ** unsafe hack.

Real bug fixed at chan.go:101.

LGTM=dave, r, iant
R=golang-codereviews, dave, r, iant
CC=dvyukov, golang-codereviews, khr
https://golang.org/cl/140870044

If system is busy burning cpu, it takes long time (about 300ms on
windows builders) to adjust prof thread priority. Once adjusted, prof
thread runs ahead of everyone else, but due to initial slowness, it
does not capture prof snapshots until start-up period is completed.

Change prof thread priority sooner, so it can start captures straight
away.

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/134360043

While we are here, give the gc helper a real function name
that will appear in stack traces.

LGTM=rlh
R=rlh
CC=dvyukov, golang-codereviews
https://golang.org/cl/133470043

This fixes the Plan 9 build.

Fix issue 8621.

LGTM=iant
R=rsc, mattn.jp, iant
CC=golang-codereviews
https://golang.org/cl/135280043

LGTM=bradfitz, rsc
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/137920044

C and Go calling conventions are now compatible, so we
don't need two versions of this function.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/139080043

LGTM=rsc
R=golang-codereviews, bradfitz, iant, khr, rsc
CC=golang-codereviews
https://golang.org/cl/139020043

Reverse dependency of https://golang.org/cl/130950043/

LGTM=agl
R=golang-codereviews, agl
CC=agl, golang-codereviews
https://golang.org/cl/138800043

Generated by a+c.

R=gobot
CC=golang-codereviews
https://golang.org/cl/134330043

The two converted files were nearly identical.
Instead of continuing that duplication, I merged them
into a single traceback.go.

Tested on arm, amd64, amd64p32, and 386.

LGTM=r
R=golang-codereviews, remyoudompheng, dave, r
CC=dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/134200044

The code I wrote originally works for trivial functions
that are inlined at a call site in another package,
because that was how I wrote my local test.
Make hex(x) work for non-inlinable functions too.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/140830043

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/133460043

Previously, if all connections were busy, we would always
re-prepare the statement on the connection we were assigned from
the pool.  That meant that if all connections were busy most of the
time, the number of prepared statements for each connection would
keep increasing over time.

Instead, after getting a free connection, check to see if the
statement has already been prepared on it, and reuse the statement
handle if so.

LGTM=bradfitz
R=golang-codereviews, gobot, bradfitz
CC=golang-codereviews
https://golang.org/cl/116930043

LGTM=bradfitz, rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews, khr
https://golang.org/cl/133240043

LGTM=dvyukov, rsc
R=golang-codereviews, dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/132440043

LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/140110043

LGTM=rsc
R=rsc, ality
CC=golang-codereviews
https://golang.org/cl/137030043

It looks like this has just always been broken:
the race detector handles running Go code on g0 of the main thread
and on g0 of any extra threads created by non-Go code, but it does
not handle running Go code on g0 of non-main threads created by Go.
Handle that.

Should fix the race build failures on the dashboard.

We're running into this now because we are running more
and more Go code on g0.

TBR=dvyukov
CC=golang-codereviews
https://golang.org/cl/137910043

The file in repo has been updated recently, but all these changes
are gone off the web site now. It seems web site gets updated once
in a while, so we'll update our file occasionally.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/140780043

Fixes #8626.

LGTM=bradfitz
R=golang-codereviews
CC=bradfitz, golang-codereviews, iant, r
https://golang.org/cl/137050043

The exported Go definitions appearing in mprof.go are
copied verbatim from debug.go.

The unexported Go funcs and types are new.
The C Bucket type used a union and was not a line-for-line translation.

LGTM=remyoudompheng
R=golang-codereviews, remyoudompheng
CC=dvyukov, golang-codereviews, iant, khr, r
https://golang.org/cl/137040043

#ifdef'ed out code wasn't updated for argp change.

TBR=iant
CC=golang-codereviews
https://golang.org/cl/139040043

It was a throw originally; it was converted incorrectly.

LGTM=dave
R=khr, dave
CC=golang-codereviews
https://golang.org/cl/139000043

Adding the #include to defs.c makes it get processed
by cmd/dist, which writes out Go equivalent for all the
C data structures defined in defs.c.

This in turn makes it necessary to define the Plink type,
used in os_plan9.h, in os_plan9.go. Rename it to _Plink
to avoid being exported.

LGTM=0intro, iant
R=golang-codereviews, iant, 0intro
CC=golang-codereviews, r
https://golang.org/cl/132490043

uintptr is better when translating to Go,
and in a few places it's better in C too.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews, iant, khr
https://golang.org/cl/138980043

This change fixes the last known false negative of the race detector --
detection of races between mutating atomic operations and non-atomic operations.
Race runtime already has functions for precise modelling of various atomic operations,
so this change just forwards all atomic ops to race runtime
instead of poor man modeling in sync/atomic package.
Performance is also improved -- full sync/atomic tests run in 60s instead of 85s now.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, rsc
https://golang.org/cl/111310044

benchmark                  old ns/op     new ns/op     delta
BenchmarkSingleMatch       49443         52275         +5.73%
BenchmarkIndex             28.8          27.4          -4.86%
BenchmarkLastIndex         14.5          14.0          -3.45%
BenchmarkLastIndexHard1    3982782       2309200       -42.02%
BenchmarkLastIndexHard2    3985562       2287715       -42.60%
BenchmarkLastIndexHard3    3555259       2282866       -35.79%

LGTM=josharian, nigeltao
R=golang-codereviews, ality, josharian, bradfitz, dave, nigeltao, gobot, nightlyone
CC=golang-codereviews
https://golang.org/cl/102560043

These haven't been run in ages.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews, iant, khr, r
https://golang.org/cl/134170043

This is needed for callers to be able to keep track of the
writing position within a zip file. Otherwise it's not
possible to compute the size of headers, and the TOC isn't
written until the very end.

LGTM=adg
R=adg
CC=golang-codereviews
https://golang.org/cl/134210043

NO CODE CHANGES HERE

The first conversion was not complete.
This CL doesn't make any actual changes,
but it inserts the missing mprof.goc code
as comments so that the next CL will have
useful diffs.

To make the diffs a bit more useful, removed
all semicolons, ->, and runtime· prefixes as well.

Also corrected order of a few functions in mprof.go
to match original order in mprof.goc.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews, iant, khr, r
https://golang.org/cl/134200043

The [568]c compilers no longer support packed structs, so
using them with -cdefs no longer works.  Just commenting out
the test, rather than removing it, in case this needs to be
handled.  It may be that -cdefs can go away entirely in the
future, in which case so can this directory.

LGTM=mdempsky
R=rsc, mdempsky
CC=golang-codereviews
https://golang.org/cl/136030043

For example:
go build -ldflags -C cmd/go 2>&1 | awk '{print $NF}' | sort | uniq -c | sort -nr

LGTM=khr
R=khr, josharian
CC=golang-codereviews
https://golang.org/cl/135170044

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/138960043

positive numbers to mean a numeric zlib compression level.

LGTM=bradfitz, ruiu
R=bradfitz, ruiu
CC=golang-codereviews, jeff.allen
https://golang.org/cl/138860043