I'm improving gccgo's detection of variables that are only set
but not used, and it triggers additional errors on this code.
The new gccgo errors are correct; gc seems to suppress them
due to the other, expected, errors.  This change uses the
variables so that no compiler will complain.

gccgo change is https://golang.org/cl/119920043 .

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/116050043

The gccgo compiler would fail this test.  The fix for gccgo is
https://golang.org/cl/116960043 .

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/118000043

GC thinks that it's an invalid pointer on plan9:
http://build.golang.org/log/f7da638a20544ef7f45e81f23fdbc4875044c296

LGTM=0intro
R=golang-codereviews, 0intro
CC=aram, golang-codereviews
https://golang.org/cl/113350043

benchmark                      old ns/op     new ns/op     delta
BenchmarkSelectUncontended     220           165           -25.00%
BenchmarkSelectContended       209           161           -22.97%
BenchmarkSelectProdCons        1042          904           -13.24%

But more importantly this change will allow
to get rid of free function in runtime.

Fixes #6494.

LGTM=rsc, khr
R=golang-codereviews, rsc, dominik.honnef, khr
CC=golang-codereviews, remyoudompheng
https://golang.org/cl/107670043

Fixes #8389.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/111320044

This is a temporary change to see how far the
builder gets when it times out.

LGTM=aram, 0intro
R=0intro, aram
CC=golang-codereviews, mischief
https://golang.org/cl/111400043

subtract freed count before span gets merged during free.

LGTM=dvyukov
R=dmitry, dvyukov
CC=golang-codereviews
https://golang.org/cl/112450045

Fix virtual address of the start of the text segment
on amd64 Plan 9.

This issue has been partially fixed in cmd/add2line,
as part of CL 106460044, but we forgot to report the
change to cmd/objdump.

In the meantime, we also fixed the textStart address
in both cmd/add2line and cmd/objdump.

LGTM=aram, ality, mischief
R=rsc, mischief, aram, ality
CC=golang-codereviews, jas
https://golang.org/cl/117920043

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/111360045

Hook pre-commit runs before 'hg commit' command whereas hook precommit runs
after the user has entered commit message.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/106320043

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/105500043

Fixes #8347.

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/109600044

The CopyFat benchmarks were changed in CL 92760044. See CL 111350043 for discussion.

LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/116000043

These benchmarks are important for performance. When compiling the stdlib:

* 77.1% of the calls to sgen (copyfat) are for 16 bytes; another 8.7% are for 24 bytes. (The next most common is 32 bytes, at 5.7%.)
* Over half the calls to clearfat are for 16 or 24 bytes.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews
https://golang.org/cl/111350043

Ken's standalone file server and its derivatives, like cwfs, return
error strings different from fossil when the user opens non-existent
files.

LGTM=aram, 0intro, r
R=0intro, aram, r
CC=golang-codereviews, ken
https://golang.org/cl/112420045

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/111330043

Also, fix a write check in writeBuf and make some bounds checks simpler.

LGTM=gri
R=golang-codereviews, adg, gri, r, minux
CC=golang-codereviews
https://golang.org/cl/113060043

This CLA replaces the one for 'snyh'.
Verified by hand.

LGTM=minux
R=iant, minux
CC=golang-codereviews
https://golang.org/cl/112420043

updatememstats is called on both the m and g stacks.
Call into flushallmcaches correctly.  flushallmcaches
can only run on the M stack.

This is somewhat temporary.  once ReadMemStats is in
Go we can have all of this code M-only.

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/116880043

Pre Go1?

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/115870043

Encoder compilation must be enc-independent,
because the resulting program is reused across
different encoders.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/115860043

Breaks build for FreeBSD. Probably clang related?

««« original CL description
cmd/cgo: disable inappropriate warnings when the gcc struct is empty

package main
//#cgo CFLAGS: -Wall
//void test() {}
import "C"
func main() {
    C.test()
}

This code will cause gcc issuing warnings about unused variable.

This commit use offset of the second return value of
Packages.structType to detect whether the gcc struct is empty,
and if it's directly invoke the C function instead of writing an
unused code.

LGTM=dave, minux
R=golang-codereviews, iant, minux, dave
CC=golang-codereviews
https://golang.org/cl/109640045

»»»

TBR=dfc
R=dave
CC=golang-codereviews
https://golang.org/cl/114990044

package main
//#cgo CFLAGS: -Wall
//void test() {}
import "C"
func main() {
    C.test()
}

This code will cause gcc issuing warnings about unused variable.

This commit use offset of the second return value of
Packages.structType to detect whether the gcc struct is empty,
and if it's directly invoke the C function instead of writing an
unused code.

LGTM=dave, minux
R=golang-codereviews, iant, minux, dave
CC=golang-codereviews
https://golang.org/cl/109640045

Fixes #8380.

Also update hashmap.go to use throwgo rather than panic.

LGTM=khr
R=khr, rsc
CC=golang-codereviews
https://golang.org/cl/115860045

redo stack allocation.  This is mostly the same as
the original CL with a few bug fixes.

1. add racemalloc() for stack allocations
2. fix poolalloc/poolfree to terminate free lists correctly.
3. adjust span ref count correctly.
4. don't use cache for sizes >= StackCacheSize.

Should fix bugs and memory leaks in original changelist.

««« original CL description
undo CL 104200047 / 318b04f28372

Breaks windows and race detector.
TBR=rsc

««« original CL description
runtime: stack allocator, separate from mallocgc

In order to move malloc to Go, we need to have a
separate stack allocator.  If we run out of stack
during malloc, malloc will not be available
to allocate a new stack.

Stacks are the last remaining FlagNoGC objects in the
GC heap.  Once they are out, we can get rid of the
distinction between the allocated/blockboundary bits.
(This will be in a separate change.)

Fixes #7468
Fixes #7424

LGTM=rsc, dvyukov
R=golang-codereviews, dvyukov, khr, dave, rsc
CC=golang-codereviews
https://golang.org/cl/104200047
»»»

TBR=rsc
CC=golang-codereviews
https://golang.org/cl/101570044
»»»

LGTM=dvyukov
R=dvyukov, dave, khr, alex.brainman
CC=golang-codereviews
https://golang.org/cl/112240044

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/118860043

Resolves TODO for not walking all goroutines in NumGoroutines.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, rsc
https://golang.org/cl/107290044

1. Add select on sync channels benchmark.
2. Make channels in BenchmarkSelectNonblock shared.
With GOMAXPROCS=1 it is the same, but with GOMAXPROCS>1
it becomes a more interesting benchmark.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews
https://golang.org/cl/115780043

Previously we had a bitmap to check whether or not a byte
appears in a string should be replaced. But we don't actually
need a separate bitmap for that purpose. Removing the bitmap
makes the code simpler.

LGTM=dave, iant, nigeltao
R=golang-codereviews, dave, gobot, nigeltao, iant, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/110100043

LGTM=adonovan, rsc
R=rsc, adonovan
CC=golang-codereviews
https://golang.org/cl/117800043

Fixes #5750.

https://code.google.com/p/go/issues/detail?id=5750

os: Separate windows from posix. Implement windows support.
path/filepath: Use the same implementation as other platforms
syscall: Add/rework new APIs for Windows

LGTM=alex.brainman
R=golang-codereviews, alex.brainman, gobot, rsc, minux
CC=golang-codereviews
https://golang.org/cl/86160044

Generated by a+c.

R=gobot
CC=golang-codereviews
https://golang.org/cl/114890043

Fixes #8378

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/114880043

"archive/tar: reuse temporary buffer in writeHeader" introduced a
change which was supposed to help lower the number of allocations from
512 bytes for every call to writeHeader. This change broke the writing
of PAX headers.

writeHeader calls writePAXHeader and writePAXHeader calls writeHeader
again. writeHeader will end up writing the PAX header twice.

example broken header:
PaxHeaders.4007/NetLock_Arany_=Class_Gold=_Ftanstvny.crt0000000000000000000000000000007112301216634021512 xustar0000000000000000
PaxHeaders.4007/NetLock_Arany_=Class_Gold=_Ftanstvny.crt0000000000000000000000000000007112301216634021512 xustar0000000000000000

example correct header:
PaxHeaders.4290/NetLock_Arany_=Class_Gold=_Ftanstvny.crt0000000000000000000000000000007112301216634021516 xustar0000000000000000
0100644000000000000000000000270412301216634007250 0ustar0000000000000000

This commit adds a dedicated buffer for pax headers to the Writer
struct. This change increases the size of the struct by 512 bytes, but
allows tar/writer to avoid allocating 512 bytes for all written
headers and it avoids allocating 512 more bytes for pax headers.

LGTM=dsymonds
R=dsymonds, dave, iant
CC=golang-codereviews
https://golang.org/cl/110480043

Pending CL 113120043.

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/112290043

Fixes #6102.

LGTM=gri
R=ken, r, gri
CC=golang-codereviews
https://golang.org/cl/113120043

The garbage collector and stack scans are good enough now.

Fixes #7446.

LGTM=r
R=r, dvyukov
CC=golang-codereviews, mdempsky, mtj
https://golang.org/cl/112870046

As written, the ! applies before the &1.
This would crash writing out missing pcdata tables
if we ever used non-contiguous IDs in a function.
We don't, but fix anyway.

LGTM=iant, minux
R=minux, iant
CC=golang-codereviews
https://golang.org/cl/117810047

It's a bit slower, but not painfully so.  There is still room for
improvement (saving space so we can use nosplit, and removing the
requirement for hash/eq stubs).

benchmark                              old ns/op     new ns/op     delta
BenchmarkMegMap                        23.5          24.2          +2.98%
BenchmarkMegOneMap                     14.9          15.7          +5.37%
BenchmarkMegEqMap                      71668         72234         +0.79%
BenchmarkMegEmptyMap                   4.05          4.93          +21.73%
BenchmarkSmallStrMap                   21.9          22.5          +2.74%
BenchmarkMapStringKeysEight_16         23.1          26.3          +13.85%
BenchmarkMapStringKeysEight_32         21.9          25.0          +14.16%
BenchmarkMapStringKeysEight_64         21.9          25.1          +14.61%
BenchmarkMapStringKeysEight_1M         21.9          25.0          +14.16%
BenchmarkIntMap                        21.8          12.5          -42.66%
BenchmarkRepeatedLookupStrMapKey32     39.3          30.2          -23.16%
BenchmarkRepeatedLookupStrMapKey1M     322353        322675        +0.10%
BenchmarkNewEmptyMap                   129           136           +5.43%
BenchmarkMapIter                       137           107           -21.90%
BenchmarkMapIterEmpty                  7.14          8.71          +21.99%
BenchmarkSameLengthMap                 5.24          6.82          +30.15%
BenchmarkBigKeyMap                     34.5          35.3          +2.32%
BenchmarkBigValMap                     36.1          36.1          +0.00%
BenchmarkSmallKeyMap                   26.9          26.7          -0.74%

LGTM=rsc
R=golang-codereviews, dave, dvyukov, rsc, gobot, khr
CC=golang-codereviews
https://golang.org/cl/99380043

A byte order mark  (BOM) cannot be backquoted.

LGTM=r
R=golang-codereviews, gobot, r
CC=golang-codereviews
https://golang.org/cl/112310043