Ensure that deadlines affect already issued IO.

R=golang-dev, mikioh.mikioh, bradfitz
CC=golang-dev
https://golang.org/cl/12847043

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12851043

Fixes #5722.

R=golang-dev, khr, cshapiro, rsc, r
CC=golang-dev
https://golang.org/cl/12670045

Just for readability reasons; to prevent overlooking deadline stuff
across over platforms.

R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/8656044

The new version does not require any memory allocations and is 30-50% faster.
Also detect and painc if Cond is copied after first.

benchmark            old ns/op    new ns/op    delta
BenchmarkCond1             317          195  -38.49%
BenchmarkCond1-2           875          607  -30.63%
BenchmarkCond1-4          1116          548  -50.90%
BenchmarkCond1-8          1013          613  -39.49%
BenchmarkCond1-16          983          450  -54.22%
BenchmarkCond2             559          352  -37.03%
BenchmarkCond2-2          1916         1378  -28.08%
BenchmarkCond2-4          1518         1322  -12.91%
BenchmarkCond2-8          2313         1291  -44.19%
BenchmarkCond2-16         1885         1078  -42.81%
BenchmarkCond4            1070          614  -42.62%
BenchmarkCond4-2          4899         3047  -37.80%
BenchmarkCond4-4          3813         3006  -21.16%
BenchmarkCond4-8          3605         3045  -15.53%
BenchmarkCond4-16         4148         2637  -36.43%
BenchmarkCond8            2086         1264  -39.41%
BenchmarkCond8-2          9961         6736  -32.38%
BenchmarkCond8-4          8135         7689   -5.48%
BenchmarkCond8-8          9623         7517  -21.89%
BenchmarkCond8-16        11661         8093  -30.60%

R=sougou, rsc, bradfitz, r
CC=golang-dev
https://golang.org/cl/11573043

If the timer goroutine is wakeup by timeout,
other goroutines will still notewakeup because sleeping is still set.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12763043

Fixes #5517.
Fixes #5659.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12183044

Fixes #6103.

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/12686045

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/12836044

R=gri, r
CC=golang-dev
https://golang.org/cl/12822043

R=golang-dev, go.peter.90, rsc, r
CC=golang-dev
https://golang.org/cl/12016043

The compilers assume they can generate temporary variables
as needed to preserve the right semantics or simplify code
generation and the back end will still generate good code.
This turns out not to be true. The back ends will only
track the first 128 variables per function and give up
on the remainder. That needs to be fixed too, in a later CL.

This CL merges temporary variables with equal types and
non-overlapping lifetimes using the greedy algorithm in
Poletto and Sarkar, "Linear Scan Register Allocation",
ACM TOPLAS 1999.

The result can be striking in the right functions.

Top 20 frame size changes in a 6g godoc binary by bytes saved:

5464 1984 (-3480, -63.7%) go/build.(*Context).Import
4456 1824 (-2632, -59.1%) go/printer.(*printer).expr1
2560   80 (-2480, -96.9%) time.nextStdChunk
3496 1608 (-1888, -54.0%) go/printer.(*printer).stmt
1896  272 (-1624, -85.7%) net/http.init
2688 1400 (-1288, -47.9%) fmt.(*pp).printReflectValue
2800 1512 (-1288, -46.0%) main.main
3296 2016 (-1280, -38.8%) crypto/tls.(*Conn).clientHandshake
1664  488 (-1176, -70.7%) time.loadZoneZip
1760  608 (-1152, -65.5%) time.parse
4104 3072 (-1032, -25.1%) runtime/pprof.writeHeap
1680  712 ( -968, -57.6%) go/ast.Walk
2488 1560 ( -928, -37.3%) crypto/x509.parseCertificate
1128  392 ( -736, -65.2%) math/big.nat.divLarge
1528  864 ( -664, -43.5%) go/printer.(*printer).fieldList
1360  712 ( -648, -47.6%) regexp/syntax.(*parser).factor
2104 1528 ( -576, -27.4%) encoding/asn1.parseField
1064  504 ( -560, -52.6%) encoding/xml.(*Decoder).text
 584   48 ( -536, -91.8%) html.init
1400  864 ( -536, -38.3%) go/doc.playExample

In the same godoc build, cuts the number of functions with
too many vars from 83 to 32.

R=ken2
CC=golang-dev
https://golang.org/cl/12829043

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12830043

If the hg checkout of go.tools fails, check for Internet
connectivity before failing.

R=golang-dev, shivakumar.gn
CC=golang-dev
https://golang.org/cl/12814043

R=ken2
CC=golang-dev
https://golang.org/cl/12827043

Now there's only one copy of the flow graph construction
and dominator computation, and different optimizations
can attach different annotations to the instructions.

R=ken2
CC=golang-dev
https://golang.org/cl/12797045

Out of context, it can be very confusing because there can be lots of Go
files in the directory, but the error message says there aren't.

R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/12823043

The call builtin unconditionally tries to convert a second return value from a function to the error type. This fails in case nil is returned, effectively making call useless for functions returning two values.

This CL adds a nil check for the second return value, and adds a test.

Note that for regular function and method calls the nil error case is handled correctly and is verified by a test.

R=r
CC=golang-dev
https://golang.org/cl/12804043

Bugs pointed out by cshapiro in CL 12637051.

R=cshapiro
CC=golang-dev
https://golang.org/cl/12815043

Code in gc/popt.c is compiled as part of 5g, 6g, and 8g,
meaning it can use arch-specific headers but there's
just one copy of the code.

This is the same arrangement we use for the portable
code generation logic in gc/pgen.c.

Move fixjmp and noreturn there to get the ball rolling.

R=ken2
CC=golang-dev
https://golang.org/cl/12789043

Malformed domain attributes are not sent in a Set-Cookie header.
Instead the domain attribute is dropped which turns the cookie
into a host-only cookie. This is much safer than dropping characters
from domain attribute.

Domain attributes with a leading dot '.' are still allowed, even
if discouraged by RFC 6265 section 4.1.1.

Fixes #6013

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12745043

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12798043

Fixes #5933.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12699051

The original plan was to collect allocation stacks
for all memory blocks. But it was never implemented
and it's not in near plans and it's unclear how to do it at all.

R=golang-dev, dave, bradfitz
CC=golang-dev
https://golang.org/cl/12724044

Fixes #6098.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12717043

Like CL 12637051, but for 5g instead of 6g.

R=ken2
CC=golang-dev
https://golang.org/cl/12779043

They are just like MOVW and should be setting only
two register fields, not three.

R=ken2
CC=golang-dev, remyoudompheng
https://golang.org/cl/12781043

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12702048

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12774043

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12773044

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12773043

Like CL 12637051, but for 8g instead of 6g.
Fix a few minor 6g errors too.

R=ken2
CC=golang-dev
https://golang.org/cl/12778043

Update #5530

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12504044

Fixes #5530.

R=golang-dev, iant, com.liigo
CC=golang-dev
https://golang.org/cl/12688044

No need for the complex condition.
Fixes #6089

R=golang-dev, mischief, adg
CC=golang-dev
https://golang.org/cl/12731043

Add new proginfo function that returns information about a
Prog*. The information includes various instruction
description bits as well as a list of required registers set
and used and indexing registers used.

Convert the large instruction switches to use proginfo.

This information was formerly duplicated in multiple
optimization passes, inconsistently. For example, the
information about which registers an instruction requires
appeared three times for most instructions.

Most of the switches were incomplete or incorrect in some way.
For example, the switch in copyu did not list cases for INCB,
JPS, MOVAPD, MOVBWSX, MOVBWZX, PCDATA, POPQ, PUSHQ, STD,
TESTB, TESTQ, and XCHGL. Those were all falling into the
"unknown instruction" default case and stopping the rewrite,
perhaps unnecessarily. Similarly, the switch in needc only
listed a handful of the instructions that use or set the carry bit.

We still need to decide whether to use proginfo to generalize
a few of the remaining smaller switches in peep.c.

If this goes well, we'll make similar changes in 8g and 5g.

R=ken2
CC=golang-dev
https://golang.org/cl/12637051

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/12698047

Fixes #5993.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/12665046

Update #5100
Update #6086

Remove switchReader, switchWriter, switchReaderPair,
switchWriterPair, etc.

Now it only maintains pools of bufio Readers and Writers, but
uses Reset instead of working around all their
previously-associated state.

Compared to before the bufio Reset change, it's the same number of
allocations, and also faster:

benchmark                                   old ns/op    new ns/op    delta
BenchmarkClientServer                          111218       109828   -1.25%
BenchmarkClientServerParallel4                  70580        70013   -0.80%
BenchmarkClientServerParallel64                 72636        68919   -5.12%
BenchmarkServer                                139858       137068   -1.99%
BenchmarkServerFakeConnNoKeepAlive              14619        14314   -2.09%
BenchmarkServerFakeConnWithKeepAlive            12390        11361   -8.31%
BenchmarkServerFakeConnWithKeepAliveLite         7630         7306   -4.25%
BenchmarkServerHandlerTypeLen                    9688         9342   -3.57%
BenchmarkServerHandlerNoLen                      8700         8470   -2.64%
BenchmarkServerHandlerNoType                     9255         8949   -3.31%
BenchmarkServerHandlerNoHeader                   7058         6806   -3.57%

benchmark                                  old allocs   new allocs    delta
BenchmarkClientServer                              61           61    0.00%
BenchmarkClientServerParallel4                     61           61    0.00%
BenchmarkClientServerParallel64                    61           61    0.00%
BenchmarkServer                                    16           16    0.00%
BenchmarkServerFakeConnNoKeepAlive                 24           24    0.00%
BenchmarkServerFakeConnWithKeepAlive               19           19    0.00%
BenchmarkServerFakeConnWithKeepAliveLite            9            9    0.00%
BenchmarkServerHandlerTypeLen                      17           17    0.00%
BenchmarkServerHandlerNoLen                        14           14    0.00%
BenchmarkServerHandlerNoType                       15           15    0.00%
BenchmarkServerHandlerNoHeader                      9            9    0.00%

benchmark                                   old bytes    new bytes    delta
BenchmarkClientServer                            6988         6985   -0.04%
BenchmarkClientServerParallel4                   6979         6985    0.09%
BenchmarkClientServerParallel64                  7002         7019    0.24%
BenchmarkServer                                  1846         1848    0.11%
BenchmarkServerFakeConnNoKeepAlive               2420         2412   -0.33%
BenchmarkServerFakeConnWithKeepAlive             2126         2129    0.14%
BenchmarkServerFakeConnWithKeepAliveLite          989          990    0.10%
BenchmarkServerHandlerTypeLen                    1818         1819    0.06%
BenchmarkServerHandlerNoLen                      1775         1777    0.11%
BenchmarkServerHandlerNoType                     1783         1785    0.11%
BenchmarkServerHandlerNoHeader                    989          990    0.10%

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12708046

Fixes #6086

R=golang-dev, pieter, r, rsc
CC=golang-dev
https://golang.org/cl/12603049