Use explicit SSE writes instead of REP STOSQ.

benchmark               old ns/op    new ns/op    delta
BenchmarkMemclr5               22            5  -73.62%
BenchmarkMemclr16              27            5  -78.49%
BenchmarkMemclr64              28            6  -76.43%
BenchmarkMemclr256             34            8  -74.94%
BenchmarkMemclr4096           112           84  -24.73%
BenchmarkMemclr65536         1902         1920   +0.95%

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/60090044

filepath.Base covers all scenarios
(for example paths like d:hello.txt)
on windows

LGTM=iant, bradfitz
R=golang-codereviews, iant, bradfitz
CC=golang-codereviews
https://golang.org/cl/59740050

This CL is in preparation to make cgo work on freebsd/arm.

The signedness of C char might be a problem when we make bare syscall
APIs, Go structures, using built-in bootstrap scripts with cgo because
they do translate C stuff to Go stuff internally. For now almost all
the C compilers assume that the type of char will be unsigned on arm
by default but it makes a different view from amd64, 386.

This CL just passes -fsigned-char, let the type of char be signed,
option which is supported on both gcc and clang to the underlying C
compilers through cgo for avoiding such inconsistency on syscall API.

LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/59740051

This CL is in preparation to make cgo work on freebsd/arm.

LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/59490051

This CL is in preparation to make cgo work on freebsd/arm.

It's just for fixing build fails on freebsd/arm, we still need to
update z-files later for fixing several package test fails.

How to generate z-files on freebsd/arm in the bootstrapping phase:
1. run freebsd on appropriate arm-eabi platforms
2. both syscall z-files and runtime def-files in the current tree are
   broken about EABI padding, fix them by hand
3. run make.bash again to build $GOTOOLDIR/cgo
4. use $GOTOOLDIR/cgo directly

LGTM=iant
R=iant, dave
CC=golang-codereviews
https://golang.org/cl/59490052

This CL is in preparation to make cgo work on freebsd/arm.

LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/60500044

This CL is in preparation to make cgo work on freebsd/arm.

How to generate defs-files on freebsd/arm in the bootstrapping phase:
1. run freebsd on appropriate arm-eabi platforms
2. both syscall z-files and runtime def-files in the current tree are
   broken about EABI padding, fix them by hand
3. run make.bash again to build $GOTOOLDIR/cgo
4. use $GOTOOLDIR/cgo directly

LGTM=minux.ma, iant
R=iant, minux.ma, dave
CC=golang-codereviews
https://golang.org/cl/59580045

Whitespace characters are allowed in quoted-string according to RFC 5322 without
being "Q"-encoding. Address.String() already always formats the name portion in
quoted string, so whitespace characters should be allowed in there.

Fixes #6641.

LGTM=dave, dsymonds
R=golang-codereviews, gobot, dsymonds, dave
CC=golang-codereviews
https://golang.org/cl/55770043

Fixes #7240.

LGTM=tommi.virtanen, bradfitz
R=golang-codereviews, tommi.virtanen, bradfitz
CC=golang-codereviews
https://golang.org/cl/60480045

I just added support for goto statements to my GopherJS project and now I am trying to get rid of my patches. These occurrences of goto however are a bit problematic:
GopherJS has to emulate gotos, so there is some performance drawback when doing so. In this case the drawback is major, since this is a core function of math/big which is called quite often. Additionally I can't see any reason here why the implementation with gotos should be preferred over my proposal.
That's why I would kindly ask to include this patch, even though it is functional equivalent to the existing code.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/55470046

So that we don't need to update the file each time a new version is released.

LGTM=dave, r, adg
R=golang-codereviews, dave, josharian, gobot, adg, r
CC=golang-codereviews
https://golang.org/cl/48730043

Introduce two new environment variables, CC_FOR_TARGET and CXX_FOR_TARGET.
CC_FOR_TARGET defaults to CC and is used when compiling for GOARCH, while
CC remains for compiling for GOHOSTARCH.
CXX_FOR_TARGET defaults to CXX and is used when compiling C++ code for
GOARCH.

CGO_ENABLED defaults to disabled when cross compiling and has to be
explicitly enabled.

Update #4714

LGTM=minux.ma, iant
R=golang-codereviews, minux.ma, iant, rsc, dominik.honnef
CC=golang-codereviews
https://golang.org/cl/57100043

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/52350044

Fixes #7034.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/57140043

Fixes #7016.

LGTM=r
R=r
CC=adg, bradfitz, dave, golang-codereviews
https://golang.org/cl/60100043

Fixes #7117.

LGTM=gri
R=golang-codereviews, gobot, gri
CC=golang-codereviews
https://golang.org/cl/53310044

This reduces the ability to fingerprint TLS connections.

The impeteus for this change was a recent change to OpenSSL
by Nick Mathewson:

http://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=2016265dfb

LGTM=agl
R=agl
CC=golang-codereviews
https://golang.org/cl/57230043

Add benchmarks for:
1. non-blocking failing receive (polling of "stop" chan)
2. channel-based semaphore (gate pattern)
3. select-based producer/consumer (pass data through a channel, but also wait on "stop" and "timeout" channels)

LGTM=r
R=golang-codereviews, r
CC=bradfitz, golang-codereviews, iant, khr
https://golang.org/cl/59040043

CL 56120043 fixed and cleaned up TLS on ARM after introducing liblink, but
left flag_shared broken. This CL restores the (unsupported) flag_shared
behaviour by simply rewriting access to $runtime.tlsgm(SB) with
runtime.tlsgm(SB), to compensate for the extra indirection when going from
the R_ARM_TLS_LE32 relocation to the R_ARM_TLS_IE32 relocation.

Also, remove unnecessary symbol lookup left after 56120043.

LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/57000043

CL 56120043 fixed TLS handling on ARM after the introduction of
liblink but left older ARM processors broken.

Before liblink, the MRC instruction was replaced with a fallback
on older ARMs. CL 56120043 removed that, because the rewrite matched
bit patterns on the AWORD pseudo-instruction and could therefore change
unrelated AWORDs that happened to match.

This CL adds an AMRC instruction to encode both MRC and MCR previously
encoded as AWORDs. Then, in liblink, the AMRC instructions are either
rewritten to AWORD, or, on goarm < 7, replaced with a branch to the
fallback.

./all.bash completes successfully on an ARMv7 with either GOARM=7 or
GOARM=5. I have verified that the fallback is indeed present in both
runtime.save_gm and runtime.load_gm when GOARM=5 but not when GOARM=7.

If all goes well, this should fix the armv5 builders.

LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/55540044

Command was (and is) documented like:
"If name contains no path separators, Command uses LookPath to
resolve the path to a complete name if possible. Otherwise it
uses name directly."

But that wasn't true. It always did LookPath, and then
set a sticky error that the user couldn't unset.
And then if cmd.Dir was changed, Start would still fail
due to the earlier sticky error being set.

This keeps LookPath in the same place as before (so no user
visible changes in cmd.Path after Command), but only does
it when the documentation says it will happen.

Also, clarify the docs about a relative Dir path.

No change in any existing behavior, except using Command
is now possible with relative paths. Previously it only
worked if you built the *Cmd by hand.

Fixes #7228

LGTM=iant
R=iant
CC=adg, golang-codereviews
https://golang.org/cl/59580044

LGTM=dave
R==r, r, dave
CC=golang-codereviews
https://golang.org/cl/59810043

Generated by addca.

LGTM=iant
R=gobot, iant
CC=golang-codereviews
https://golang.org/cl/59770043

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59550044

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/51430044

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59410044

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59450044

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59460043

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/54800045

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59450043

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59440043

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/56730044

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59430043

Generated by addca.

TBR=iant
R=gobot
CC=golang-codereviews
https://golang.org/cl/59420043

Fixes #6874.

Use runtime.GC() as a stronger version of runtime.Gosched() which tends to bias the running goroutine in an otherwise idle system. This appears to reduce the worst case number of spins from 600 down to 30 on my 2 core system under high load.

LGTM=iant
R=golang-codereviews, lucio.dere, iant, dvyukov
CC=golang-codereviews
https://golang.org/cl/56540046

No functional changes, just more readable code.

LGTM=r
R=golang-codereviews, gobot, r
CC=golang-codereviews
https://golang.org/cl/59240043

If a LowerUpper ever happens, maketables will complain.

Fixes #7002.

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/59210044

LGTM=r
R=golang-codereviews, r, arnehormann, bradfitz
CC=golang-codereviews
https://golang.org/cl/58450043

I don't know what is n, but it exists somewhere there.

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/58710043

LGTM=alex.brainman
R=golang-codereviews, alex.brainman
CC=dave, golang-codereviews
https://golang.org/cl/58900044