On stack overflow, if all frames on the stack are
copyable, we copy the frames to a new stack twice
as large as the old one.  During GC, if a G is using
less than 1/4 of its stack, copy the stack to a stack
half its size.

TODO
- Do something about C frames.  When a C frame is in the
  stack segment, it isn't copyable.  We allocate a new segment
  in this case.
  - For idempotent C code, we can abort it, copy the stack,
    then retry.  I'm working on a separate CL for this.
  - For other C code, we can raise the stackguard
    to the lowest Go frame so the next call that Go frame
    makes triggers a copy, which will then succeed.
- Pick a starting stack size?

The plan is that eventually we reach a point where the
stack contains only copyable frames.

LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/54650044

The cached computed interface tables are indexed by the interface
types, not by the unnamed underlying interfaces

To preserve the invariants expected by interface comparison, an
itab generated for an interface type must not be used for a value
of a different interface type even if the representation is identical.

Fixes #7207.

LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/69210044

Generated by addca. Manually added gmail address.

LGTM=dsymonds
R=golang-codereviews
CC=adg, dsymonds, golang-codereviews
https://golang.org/cl/69240045

Update #6007

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/69040045

MCaches	now hold a MSpan for each sizeclass which they have
exclusive access to allocate from, so no lock is needed.

Modifying the heap bitmaps also no longer requires a cas.

runtime.free gets more expensive.  But we don't use it
much any more.

It's not much faster on 1 processor, but it's a lot
faster on multiple processors.

benchmark                 old ns/op    new ns/op    delta
BenchmarkSetTypeNoPtr1           24           23   -0.42%
BenchmarkSetTypeNoPtr2           33           34   +0.89%
BenchmarkSetTypePtr1             51           49   -3.72%
BenchmarkSetTypePtr2             55           54   -1.98%

benchmark                old ns/op    new ns/op    delta
BenchmarkAllocation          52739        50770   -3.73%
BenchmarkAllocation-2        33957        34141   +0.54%
BenchmarkAllocation-3        33326        29015  -12.94%
BenchmarkAllocation-4        38105        25795  -32.31%
BenchmarkAllocation-5        68055        24409  -64.13%
BenchmarkAllocation-6        71544        23488  -67.17%
BenchmarkAllocation-7        68374        23041  -66.30%
BenchmarkAllocation-8        70117        20758  -70.40%

LGTM=rsc, dvyukov
R=dvyukov, bradfitz, khr, rsc
CC=golang-codereviews
https://golang.org/cl/46810043

Functions that "fit" on one line and were on one
line in the original source are not broken up into
two lines anymore simply because they contain a comment.

- Fine-tuned use of separating blanks after /*-style comments, so:

( /* extra blank after this comment */ )
(a int /* no extra blank after this comment*/)

- Factored out comment state (from printer state) into commentInfo.
- No impact on $GOROOT/src, misc formatting.

Fixes #5543.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/68630043

Fixes #7413.

LGTM=rsc
R=remyoudompheng
CC=golang-codereviews, r, rsc
https://golang.org/cl/69180044

From the original description in CL 15770043

The main change here is to consult $GOARCH.

In 6c, when GOOS=nacl, some of the more complex addressing modes must be disabled, and the BP and R15 registers must not be used.

See golang.org/s/go13nacl for design overview.

LGTM=rsc
R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/69020044

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/68980044

This partly addresses issue 6099 where a gofmt rewrite is behaving
unexpectedly because the provided rewrite term is not a valid expression
but is silently consumed anyway.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/68920044

These are mistakes in the first big NaCl CL.

LGTM=minux.ma, iant
R=golang-codereviews, minux.ma, iant
CC=golang-codereviews
https://golang.org/cl/69200043

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/68650045

LGTM=dave, rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/68960044

The gvardef function does nothing if n->class == PEXTERN, so
we don't need to test for that before calling it.  This makes
the 6g/8g code more like the 5g code and clarifies that the
cases that do not test for n->class != PEXTERN are not buggy.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68900044

Switch nanotime to a monotonic clock on openbsd/386 and openbsd/amd64.
Also use a monotonic clock when for thrsleep, since the sleep duration
is based on the value returned from nanotime.

Update #6007

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/68460044

See the discussion on the original CL for context:
        https://golang.org/cl/60100043/

LGTM=josharian
R=r, josharian
CC=golang-codereviews
https://golang.org/cl/68890043

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/68820043

LGTM=iant, aram, dave
R=golang-codereviews, iant, aram, dave
CC=golang-codereviews
https://golang.org/cl/68770044

For now we don't use CLOCK_MONOTONIC_FAST instead because
it's not supported on prior to 9-STABLE.

Update #6007

LGTM=minux.ma
R=golang-codereviews, minux.ma, bradfitz
CC=golang-codereviews
https://golang.org/cl/68690043

maxstksize is superfluous and appears to be vestigial. 6g does not use it.

c >= 4 cannot occur; c = w % 4.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68750043

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/68760043

These previously reviewed CLs are present in this CL.

---
changeset:   18445:436bb084caed
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 09:50:34 2013 -0500
description:
runtime: assembly and system calls for Native Client x86-64

See golang.org/s/go13nacl for design overview.

This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.

This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.

R≡adg
https://golang.org/cl/15760044

---
changeset:   18448:90bd871b5994
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 09:51:36 2013 -0500
description:
runtime: amd64p32 and Native Client assembly bootstrap

See golang.org/s/go13nacl for design overview.

This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.

This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.

R≡khr
https://golang.org/cl/15820043

---
changeset:   18449:b011c3dc687e
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 09:51:58 2013 -0500
description:
math: amd64p32 assembly routines

These routines only manipulate float64 values,
so the amd64 and amd64p32 can share assembly.

The large number of files is symptomatic of a problem
with package path: it is a Go package structured like a C library.
But that will need to wait for another day.

See golang.org/s/go13nacl for design overview.

This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.

This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.

R≡bradfitz
https://golang.org/cl/15870043

---
changeset:   18450:43234f082eec
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 10:03:19 2013 -0500
description:
syscall: networking for Native Client

See golang.org/s/go13nacl for design overview.

This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.

This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.

R≡rsc
https://golang.org/cl/15780043

---
changeset:   18451:9c8d1d890aaa
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 10:03:34 2013 -0500
description:
runtime: assembly and system calls for Native Client x86-32

See golang.org/s/go13nacl for design overview.

This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.

This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.

R≡rsc
https://golang.org/cl/15800043

---
changeset:   18452:f90b1dd9228f
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 11:04:09 2013 -0500
description:
runtime: fix frame size for linux/amd64 runtime.raise

R≡rsc
https://golang.org/cl/24480043

---
changeset:   18445:436bb084caed
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 09:50:34 2013 -0500
description:
runtime: assembly and system calls for Native Client x86-64

See golang.org/s/go13nacl for design overview.

This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.

This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.

R≡adg
https://golang.org/cl/15760044

---
changeset:   18455:53b06799a938
user:        Russ Cox <rsc@golang.org>
date:        Mon Nov 11 23:29:52 2013 -0500
description:
cmd/gc: add -nolocalimports flag

R≡dsymonds
https://golang.org/cl/24990043

---
changeset:   18456:24f64e1eaa8a
user:        Russ Cox <rsc@golang.org>
date:        Tue Nov 12 22:06:29 2013 -0500
description:
runtime: add comments for playback write

R≡adg
https://golang.org/cl/25190043

---
changeset:   18457:d1f615bbb6e4
user:        Russ Cox <rsc@golang.org>
date:        Wed Nov 13 17:03:52 2013 -0500
description:
runtime: write only to NaCl stdout, never to NaCl stderr

NaCl writes some other messages on standard error
that we would like to be able to squelch.

R≡adg
https://golang.org/cl/26240044

---
changeset:   18458:1f01be1a1dc2
tag:         tip
user:        Russ Cox <rsc@golang.org>
date:        Wed Nov 13 19:45:16 2013 -0500
description:
runtime: remove apparent debugging dreg

Setting timens to 0 turns off fake time.

TBR≡adg
https://golang.org/cl/26400043

LGTM=bradfitz
R=dave, bradfitz
CC=golang-codereviews
https://golang.org/cl/68730043

Solaris does not define syscall.{Mmap,Munmap}. Move the Mmap test to a new file and exclude solaris as discussed.

LGTM=aram
R=aram, mikioh.mikioh, iant
CC=golang-codereviews
https://golang.org/cl/68720043

LGTM=bradfitz
R=golang-codereviews, bradfitz, khr
CC=golang-codereviews
https://golang.org/cl/68680043

Regression from https://golang.org/cl/68490043/diff/60001/src/pkg/crypto/sha1/sha1block_decl.go

Fixes arm build.

TBR=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68080046

An absent condition/tag in for and switch statements is equivalent
to the predeclared constant true; not simply the expression true
(which might lead to a locally defined true).

Not a language change.

Fixes #7404.

LGTM=iant, r
R=r, iant, rsc, ken
CC=golang-codereviews
https://golang.org/cl/68150046

CL 68150047 lost runtime.panicdivide.

TBR=dfc
CC=golang-codereviews
https://golang.org/cl/68610043

The parser was assuming it would find <body> or </head>.
If the entire response is just <meta> tags, it finds EOF and
treats that as an error. It's not.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/68520044

Update #3362

LGTM=agl
R=agl
CC=golang-codereviews
https://golang.org/cl/68150045

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/68600043

The new flag was added by CL 68150047 (part of the NaCl replay),
but the change, like the original, omitted documentation of the
new behavior.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/68580043

See golang.org/s/go13nacl for design overview.

This CL is the mostly mechanical changes from rsc's Go 1.2 based NaCl branch, specifically 39cb35750369 to 500771b477cf from https://code.google.com/r/rsc-go13nacl. This CL does not include working NaCl support, there are probably two or three more large merges to come.

CL 15750044 is not included as it involves more invasive changes to the linker which will need to be merged separately.

The exact change lists included are

15050047: syscall: support for Native Client
15360044: syscall: unzip implementation for Native Client
15370044: syscall: Native Client SRPC implementation
15400047: cmd/dist, cmd/go, go/build, test: support for Native Client
15410048: runtime: support for Native Client
15410049: syscall: file descriptor table for Native Client
15410050: syscall: in-memory file system for Native Client
15440048: all: update +build lines for Native Client port
15540045: cmd/6g, cmd/8g, cmd/gc: support for Native Client
15570045: os: support for Native Client
15680044: crypto/..., hash/crc32, reflect, sync/atomic: support for amd64p32
15690044: net: support for Native Client
15690048: runtime: support for fake time like on Go Playground
15690051: build: disable various tests on Native Client

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68150047

Update #6007

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/67730048

This CL adds a test that calls Mmap and Munmap through Syscall9
as the canary that detects assembly fragment breakage. For now
there is no package test that uses Syscall9 in the standard
library across all Unix-like systems.

Note that the package runtime owns its assembly fragments, so
this canary never works for runtime breakage.

LGTM=iant, bradfitz
R=iant, minux.ma, bradfitz
CC=golang-codereviews
https://golang.org/cl/61520049

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/68050043

These are only the new files, autogenerated files are in a
different CL to keep the size down.

LGTM=dave, minux.ma, jsing
R=golang-codereviews, dave, jsing, gobot, minux.ma, rsc, iant, mikioh.mikioh
CC=golang-codereviews
https://golang.org/cl/36000043

LGTM=minux.ma, mikioh.mikioh
R=golang-codereviews, minux.ma, gobot, jsing, mikioh.mikioh, dave
CC=golang-codereviews
https://golang.org/cl/36010043

LGTM=dave, rsc
R=golang-codereviews, minux.ma, mikioh.mikioh, dave, iant, rsc
CC=golang-codereviews
https://golang.org/cl/36030043

Does not change src, misc formatting.

Fixes #5623.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/68400043

Update #3362

Also set a 30 second timeout, instead of relying on the
operating system's timeout, which if often but not always 3
minutes.

LGTM=crawshaw
R=rsc, crawshaw
CC=golang-codereviews
https://golang.org/cl/68330046