New in Go 1 will be nanosecond precision in the result of time.Now on Linux.
This will break code that stores time in external formats at microsecond
precision, reads it back, and expects to get exactly the same time.

Code like that can be fixed by using time.Now().Round(time.Microsecond)
instead of time.Now() in those contexts.

R=golang-dev, bradfitz, iant, remyoudompheng
CC=golang-dev
https://golang.org/cl/6903050

Fixes #4252.

R=rsc, golang-dev, mirtchovski, daniel.morsing, dave, lvd
CC=golang-dev
https://golang.org/cl/6856126

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/6901056

This makes sure the outputs do not change for a fixed seed.
See also https://golang.org/cl/6905049.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6907048

This changes the output of

rand.Seed(0)
perm := rand.Perm(100)

When giving the same seeds to Go 1.0 and Go 1.1 programs
I would like them to generate the same random numbers.

««« original CL description
math/rand: remove noop iteration in Perm

The first iteration always do `m[0], m[0] = m[0], m[0]`, because
`rand.Intn(1)` is 0.

fun note: IIRC in TAOCP version of this algorithm, `i` goes
backward (n-1->1), meaning that the "already" shuffled part of the
array is never altered betweens iterations, while in the current
implementation the "not-yet" shuffled part of the array is
conserved between iterations.

R=golang-dev
CC=golang-dev
https://golang.org/cl/6845121

»»»

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6905049

R=rsc
CC=golang-dev
https://golang.org/cl/6889052

Fixes #4457.

R=rsc, iant, r, ken
CC=golang-dev
https://golang.org/cl/6862046

gotype can now handle much of the standard library.

- marked packages which have type checker issues
- this CL depends on CL 6846131

R=rsc
CC=golang-dev
https://golang.org/cl/6850130

Also:
- better handling of type assertions
- implemented built-in error type
- first cut at handling variadic function signatures
- several bug fixes

R=rsc, rogpeppe
CC=golang-dev
https://golang.org/cl/6846131

R=rsc
CC=golang-dev
https://golang.org/cl/6867062

The spec didn't preclude invalid type assertions and
type switches, i.e., cases where a concrete type doesn't
implement the interface type in the assertion in the first
place. Both, the gc and gccgo compiler exclude these cases.
This is documenting the status quo.

Also:
- minor clean up of respective examples
- added sentence about default case in select statements

Fixes #4472.

R=rsc, iant, r, ken
CC=golang-dev
https://golang.org/cl/6869050

Fixes #2615.

R=dave, minux.ma, iant, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6847078

Also fixes a necessary TODO in the process.

Fixes #4126

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6869053

R=rsc, golang-dev
CC=golang-dev
https://golang.org/cl/6884046

The fixjmp step eliminates redundant chains of JMP
instructions that are produced by the compiler during
code generation.

It is already implemented in gc, and can be adapted to 6c/8c with
the exception that JMPs refer to destination by pc instead of by
pointer. The algorithm is modified to operate on Regs instead of Progs
for this reason. The pcs are already restored later by regopt.

R=goalng-dev, rsc
CC=golang-dev
https://golang.org/cl/6865046

Add missing file that should have been included in CL 6854063 / 5eac1a2d6fc3

R=remyoudompheng, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6891049

The 0-length part is fine, but some callers that write 0 bytes
also pass nil as the data pointer, and the Plan 9 kernel kills the
process with 'invalid address in sys call' in that case.

R=ken2
CC=golang-dev
https://golang.org/cl/6862051

R=gri
CC=golang-dev
https://golang.org/cl/6890047

Fixes #2458.

R=mikioh.mikioh, rsc
CC=golang-dev
https://golang.org/cl/6869054

R=golang-dev
CC=golang-dev
https://golang.org/cl/6883046

Fixes #2510

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6867050

Per the curl man page, the http_proxy configuration can be
of the form:

   [protocol://]<host>[:port]

And we had a test that <ip>:<port> worked, but if
the host began with a letter, url.Parse parsed the hostname
as the scheme instead, confusing ProxyFromEnvironment.

R=golang-dev
CC=golang-dev
https://golang.org/cl/6875060

Used to say:

issue4251.go:12: inverted slice range
issue4251.go:12: constant -1 overflows uint64
issue4251.go:16: inverted slice range
issue4251.go:16: constant -1 overflows uint64
issue4251.go:20: inverted slice range
issue4251.go:20: constant -1 overflows uint64

With this patch, only gives the "inverted slice range" errors.

R=golang-dev, daniel.morsing
CC=golang-dev
https://golang.org/cl/6871058

Fixes #4396.

For fixed arrays larger than the unmapped page, agenr would general a nil check by loading the first word of the array. However there is no requirement for the first element of a byte array to be word aligned, so this check causes a trap on ARMv5 hardware (ARMv6 since relaxed that restriction, but it probably still comes at a cost).

Switching the check to MOVB ensures alignment is not an issue. This check is only invoked in a few places in the code where large fixed arrays are embedded into structs, compress/lzw is the biggest offender, and switching to MOVB has no observable performance penalty.

Thanks to Rémy and Daniel Morsing for helping me debug this on IRC last night.

R=remyoudompheng, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6854063

Fixes #4434.

This proposal replaces the previous CL 6855110. Due to issue 599, 64-bit atomic operations should probably be avoided, so use a sync.Mutex instead.

Benchmark comparisons against 025b9d070a85 on linux/386:

CL 6855110:

benchmark                        old ns/op    new ns/op    delta
BenchmarkTCPOneShot                 710024       727409   +2.45%
BenchmarkTCPOneShotTimeout          758178       768620   +1.38%
BenchmarkTCPPersistent              223464       228058   +2.06%
BenchmarkTCPPersistentTimeout       234494       242600   +3.46%

This proposal:

benchmark                        old ns/op    new ns/op    delta
BenchmarkTCPOneShot                 710024       718492   +1.19%
BenchmarkTCPOneShotTimeout          758178       748783   -1.24%
BenchmarkTCPPersistent              223464       227628   +1.86%
BenchmarkTCPPersistentTimeout       234494       238321   +1.63%

R=rsc, dvyukov, mikioh.mikioh, alex.brainman, bradfitz
CC=golang-dev, remyoudompheng
https://golang.org/cl/6866050

R=dave, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/6873046

Fixes #4281

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6872053

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6868067

The current spec says that when calling make, if both len and
cap are constant, it is an error if len > cap.  The gc
compiler does not yet implement that, but when it does this
will need to change.  Changing it now for the benefit of
gccgo.

R=gri
CC=golang-dev
https://golang.org/cl/6867064

Using append simplifies the code and makes it work if
the initial capacity of the slice is smaller than the
number of items pushed.

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/6869060

R=bradfitz
CC=golang-dev
https://golang.org/cl/6871060

Also: fix an incorrect link.

Fixes #4479.
Fixes #4456.

R=rsc, iant, r, ken
CC=golang-dev
https://golang.org/cl/6868062

R=gri
CC=golang-dev
https://golang.org/cl/6868059

Fixes #4172

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6872055

R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/6871057

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6874056

R=golang-dev
CC=golang-dev
https://golang.org/cl/6868057

R=gri
CC=golang-dev
https://golang.org/cl/6871054

R=gri
CC=golang-dev
https://golang.org/cl/6870053

R=golang-dev, remyoudompheng, iant
CC=golang-dev
https://golang.org/cl/6863055