When we release memory to the OS, if the OS doesn't want us
to release it (for example, because the program executed
mlockall(MCL_FUTURE)), madvise will fail. Ignore the failure
instead of crashing.

Fixes #3435.

R=ken2
CC=golang-dev
https://golang.org/cl/6998052

benchmark             old ns/op    new ns/op    delta
BenchmarkDefer              165          113  -31.52%
BenchmarkDefer10            155          103  -33.55%
BenchmarkDeferMany          216          158  -26.85%

benchmark            old allocs   new allocs    delta
BenchmarkDefer                1            0  -100.00%
BenchmarkDefer10              1            0  -100.00%
BenchmarkDeferMany            1            0  -100.00%

benchmark             old bytes    new bytes    delta
BenchmarkDefer               64            0  -100.00%
BenchmarkDefer10             64            0  -100.00%
BenchmarkDeferMany           64           66    3.12%

Fixes #2364.

R=ken2
CC=golang-dev
https://golang.org/cl/7001051

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6971048

Close the read side of the pipe.
Fixes #4551.

R=rsc
CC=golang-dev
https://golang.org/cl/6962049

Fixes #3887.

R=golang-dev, daniel.morsing, remyoudompheng, rsc
CC=golang-dev
https://golang.org/cl/6997045

Fixes #4581.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7000052

Any flag.Value that has an IsBoolFlag method that returns true
will be treated as a bool flag type during parsing.

Fixes #4262.

R=bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6944064

The patch makes the compile user an ordinary package-local
symbol for the name of embedded fields of builtin type.

This is incompatible with the fix delivered for issue 2687
(revision 3c060add43fb) but fixes it in a different way, because
the explicit symbol on the field makes the typechecker able to
find it in lookdot.

Fixes #3552.

R=lvd, rsc, daniel.morsing
CC=golang-dev
https://golang.org/cl/6866047

The typechecking code was doing an extra, unnecessary
indirection.

Fixes #4458.

R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6998051

Fixes #4470.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6949073

Replacement for GOEXPERIMENT=zerostack, easier to use.
Does not require a separate toolchain.

R=ken2
CC=golang-dev
https://golang.org/cl/6996051

remove zerostack compiler experiment; will do at link time instead

««« original CL description
cmd/gc: add GOEXPERIMENT=zerostack to clear stack on function entry

This is expensive but it might be useful in cases where
people are suffering from false positives during garbage
collection and are willing to trade the CPU time for getting
rid of the false positives.

On the other hand it only eliminates false positives caused
by other function calls, not false positives caused by dead
temporaries stored in the current function call.

The 5g/6g/8g changes were pulled out of the history, from
the last time we needed to do this (to work around a goto bug).
The code in go.h, lex.c, pgen.c is new but tiny.

R=ken2
CC=golang-dev
https://golang.org/cl/6938073
»»»

R=ken2
CC=golang-dev
https://golang.org/cl/7002051

When using subexpressions ($1) as replacements, when they either don't exist or values weren't found causes a panic.
This patch ensures that the match location isn't -1, to prevent out of bounds errors.
Fixes #3816.

R=franciscossouza, rsc
CC=golang-dev
https://golang.org/cl/6931049

Generated by addca.

R=gobot
CC=golang-dev
https://golang.org/cl/7007051

EDE2 is a rare DES mode that can be implemented with crypto/des, but
it's somewhat non-obvious so this CL adds an example of doing so.

Fixes #3537.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6721056

Fixes #4579.

R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7000051

Fixes #4562.

R=ken2
CC=golang-dev
https://golang.org/cl/7008044

Fixes #3559.

This makes Marshal handle fields marked ",any" instead of ignoring
them. That makes Marshal more symmetrical with Unmarshal, which seems
to have been a design goal.

Note some test cases were changed, because this patch changes
marshalling behavior. I think the previous behavior was buggy, but
there's still a backward-compatibility question to consider.

R=rsc
CC=golang-dev, n13m3y3r
https://golang.org/cl/6938068

R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7003049

Also restore the smallintconst case for binary ops.

Fixes #3835.

R=daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6999043

Most benchmarks are within the 3% margin of error. This code path is quite common in the fmt package.

linux/arm, Freescale iMX.53 (cortex-a8)

fmt:
benchmark                      old ns/op    new ns/op    delta
BenchmarkSprintfEmpty                925          785  -15.14%
BenchmarkSprintfString              5050         5039   -0.22%
BenchmarkSprintfInt                 4425         4406   -0.43%
BenchmarkSprintfIntInt              5802         5762   -0.69%
BenchmarkSprintfPrefixedInt         7029         6541   -6.94%
BenchmarkSprintfFloat              10278        10083   -1.90%
BenchmarkManyArgs                  18558        17606   -5.13%
BenchmarkScanInts               15592690     15415360   -1.14%
BenchmarkScanRecursiveInt       25155020     25050900   -0.41%

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6921056

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6996046

Taken from upstream pprof.

Fixes #4564.

R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/6952045

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6997043

Fixes #4557.

R=dave, rsc
CC=golang-dev
https://golang.org/cl/6946078

This disables checks for limited address space
and unlimited stack. They are not required for Go.
Fixes #4577.

R=golang-dev, iant
CC=golang-dev, kamil.kisiel, minux.ma
https://golang.org/cl/7003045

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7006043

Avoids unlink the underlying file before the socket close.

R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/7004044

R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/6944066

Followup to 6971049.

R=bradfitz
CC=golang-dev
https://golang.org/cl/6970049

Fixes #4580.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7002043

A fatal error used to happen when escassign-ing a multiple
function return to a single node. However, the situation
naturally appears when using "go f(g())" or "defer f(g())",
because g() is escassign-ed to sink.

Fixes #4529.

R=golang-dev, lvd, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6920060

Fixes #4309.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6974045

Fixes #4543.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6971050

This guarantees that powers of two return exact answers.

We could do a multiprecision approximation for the
rest of the answer too, but this seems like it should be
good enough.

Fixes #4567.

R=golang-dev, iant, remyoudompheng
CC=golang-dev
https://golang.org/cl/6943074

Enable cgo on OpenBSD.

The OpenBSD ld.so(1) does not currently support PT_TLS sections. Work
around this by fixing up the TCB that has been provided by librthread
and reallocating a TCB with additional space for TLS. Also provide a
wrapper for pthread_create, allowing zeroed TLS to be allocated for
threads created externally to Go.

Joint work with Shenghou Ma (minux).

Requires change 6846064.

Fixes #3205.

R=golang-dev, minux.ma, iant, rsc, iant
CC=golang-dev
https://golang.org/cl/6853059

The OpenBSD ld.so(1) does not currently support PT_TLS and refuses
to load ELF binaries that contain PT_TLS sections. Do not emit PT_TLS
sections - we will handle this appropriately in runtime/cgo instead.

R=golang-dev, minux.ma, iant
CC=golang-dev
https://golang.org/cl/6846064

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6968049

Fixes #4550.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6973048

If a handler did a panic(nil), the connection was never closed.

Fixes #4050

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6971049