runtime: double-check that symbol table is sorted

If the symbol table is unsorted, the binary search in findfunc
will not find its func, which will make stack traces stop early.
When the garbage collector starts using the stack tracer,
that would be a serious problem.

The unsorted symbol addresses came from from two things:

1. The symbols in an ELF object are not necessarily sorted,
   so sort them before adding them to the symbol list.

2. The __i686.get_pc_thunk.bx symbol is present in multiple
   object files and was having its address adjusted multiple
   times, producing an incorrect address in the symbol table.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7440044

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7413045

Also add a report about "invalid type" from gotype, if -v is set.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7420045

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7431046

This is the plan for how to make host linking work with
the rest of the system.

There are two complications:

1. It is a goal to preserve the property that pure Go programs
(even ones importing "net") can be compiled without needing
gcc, so that a Go toolchain download works out of the box.
This forces the support for two linking modes: with and without
gcc.

2. It is a goal to allow users with old copies of SWIG to continue
to use those copies. This forces the support for "internal only"
packages. Perhaps it is reasonable to require a new SWIG.
I don't know.

R=iant
CC=golang-dev
https://golang.org/cl/7433043

This reveals the presence of control and non-printable characters in the
errors returned by the Parse functions.  Also add unit tests for NumError.

R=golang-dev, r, rsc
CC=golang-dev
https://golang.org/cl/7393075

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7444045

The test suite for ReadResponse was not checking the error return on the io.Copy
on the body. This was masking two errors: the handling of chunked responses to
HEAD requests and the handling of Content-Length > 0 to HEAD.

The former manifested itself as an 'unexpected EOF' when doing the io.Copy
because a chunked reader was assigned but there were no chunks to read. The
latter cause (*http.Response).Write to report an error on HEAD requests
because it saw a Content-Length > 0 and expected a body.

There was also a missing \r\n in one chunked test that meant that the chunked
encoding was malformed. This does not appear to have been intentional.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7407046

also move a cgo-depend test to appropriate source file in runtime.

R=golang-dev, dave, adg, rsc
CC=golang-dev
https://golang.org/cl/7393063

Fixes #4769.

R=golang-dev, dave, adg, bradfitz
CC=fullung, golang-dev
https://golang.org/cl/7322089

Revision 6a88e1893941 corrupts the argument to
racefuncenter by pushing the data block pointer
to the stack.

Fixes #4885.

R=dvyukov, rsc
CC=golang-dev
https://golang.org/cl/7381053

Ignore problematic tests and un-ignore one
we can now pass.

R=rsc, rminnich, ality, dave, bradfitz
CC=golang-dev
https://golang.org/cl/7396060

This CL reduces unnecessary network facility lookups introduced
by recent changes below.

changeset: 15798:53a4da6a4f4a
net: return correct point-to-point interface address on linux

changeset: 15799:a81ef8e0cc05
net: set up IPv6 scoped addressing zone for network facilities

Also adds a test case for issue	4839.

Benchmark results on linux/amd64, virtual machine:
benchmark                                 old ns/op    new ns/op    delta
BenchmarkInterfaces-2                         80487        80382   -0.13%
BenchmarkInterfaceByIndex-2                   72013        71391   -0.86%
BenchmarkInterfaceByName-2                    79865        80101   +0.30%
BenchmarkInterfaceAddrs-2                     42071       829677  +1872.09%
BenchmarkInterfacesAndAddrs-2                 35016       607622  +1635.27%
BenchmarkInterfacesAndMulticastAddrs-2       169849       169082   -0.45%
old: 15797:9c3930413c1b, new: tip

Benchmark results on linux/amd64, virtual machine:
benchmark                                 old ns/op    new ns/op    delta
BenchmarkInterfaces-2                         80487        81459   +1.21%
BenchmarkInterfaceByIndex-2                   72013        71512   -0.70%
BenchmarkInterfaceByName-2                    79865        80567   +0.88%
BenchmarkInterfaceAddrs-2                     42071       120108  +185.49%
BenchmarkInterfacesAndAddrs-2                 35016        33259   -5.02%
BenchmarkInterfacesAndMulticastAddrs-2       169849        82391  -51.49%
old: 15797:9c3930413c1b, new: tip+CL7400055

Benchmark results on darwin/amd64:
benchmark                                 old ns/op    new ns/op    delta
BenchmarkInterfaces-2                         34402        34231   -0.50%
BenchmarkInterfaceByIndex-2                   13192        12956   -1.79%
BenchmarkInterfaceByName-2                    34791        34388   -1.16%
BenchmarkInterfaceAddrs-2                     36565        63906  +74.77%
BenchmarkInterfacesAndAddrs-2                 17497        31068  +77.56%
BenchmarkInterfacesAndMulticastAddrs-2        25276        66711  +163.93%
old: 15797:9c3930413c1b, new: tip

Benchmark results on darwin/amd64:
benchmark                                 old ns/op    new ns/op    delta
BenchmarkInterfaces-2                         34402        31854   -7.41%
BenchmarkInterfaceByIndex-2                   13192        12950   -1.83%
BenchmarkInterfaceByName-2                    34791        31926   -8.23%
BenchmarkInterfaceAddrs-2                     36565        42144  +15.26%
BenchmarkInterfacesAndAddrs-2                 17497        17329   -0.96%
BenchmarkInterfacesAndMulticastAddrs-2        25276        24870   -1.61%
old: 15797:9c3930413c1b, new: tip+CL7400055

Update #4234.
Fixes #4839 (again).
Fixes #4866.

R=golang-dev, fullung
CC=golang-dev
https://golang.org/cl/7400055

syscall: Use NewError for all system errors and introduce
        some new errors for compatibility with other packages
        and proper error handling in net. Also introduce
        Temporary and Timeout methods on ErrorString.

net: Make errors from dial, accept, listen functions follow the
        OpError standard and discern whether the underlying
        error came from syscall. Since Plan 9 uses a correspondence
        between file and network operations, all system error
        reporting happens through the underlying file operation.
        In Go code, we go through package os for file operations,
        so there is another level of indirection in error types.
        This change allows us to compare the errors with those in
        package syscall, when appropriate.

os: Just use the error string already present in package os,
        instead of calling out to package syscall.

R=rsc, ality, rminnich, bradfitz
CC=golang-dev
https://golang.org/cl/7398054

Map order is non-deterministic. Introduce a new
environment string array that tracks the env map.
This allows us to produce identical results for
Environ() upon successive calls, as expected by the
TestConsistentEnviron test in package os.

R=rsc, ality, rminnich, bradfitz, r
CC=golang-dev
https://golang.org/cl/7411047

The installer package will now detect a previous installation and warn the user
that the previous installation will be deleted. If the user continues, the
installer will delete the previous installation and install the package as
usual.

Fixes #4293.

R=adg
CC=golang-dev
https://golang.org/cl/7427044

Generated by addca.

R=gobot
CC=golang-dev
https://golang.org/cl/7432043

R=golang-dev, r, bradfitz, iant
CC=golang-dev
https://golang.org/cl/7407050

It's not a big deal, but it's easy to fix.

R=dsymonds
CC=dr.volker.dobler, golang-dev
https://golang.org/cl/7425043

New tests added for port handling and IDNA domains.
A new test case contains several redundant
tests but provides a nice documentation of the
implemented rules for domain handling.

R=nigeltao
CC=golang-dev
https://golang.org/cl/7393070

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7230059

Fixes #4873.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7421043

Update #4842

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7369060

Also delete bogus tests for f.pkg (does the file have a package) since all
files have a package attached. The tests for pkg.types and pkg.values
suffice.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7418043

These are superseded by the tool at misc/dist.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7420044

R=r
CC=golang-dev
https://golang.org/cl/7375060

Permits all sorts of custom HTTP timeout policies without
adding a new Transport timeout Duration for each combination
of HTTP phases.

This keeps track internally of which TCP connection a given
Request is on, and lets callers forcefully close the TCP
connection for a given request, without actually getting
the net.Conn directly.

Additionally, a future CL will implement res.Body.Close (Issue
3672) in terms of this.

Update #3362
Update #3672

R=golang-dev, rsc, adg
CC=golang-dev
https://golang.org/cl/7372054

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7420043

Fixes #4897.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7377061

R=adonovan
CC=golang-dev
https://golang.org/cl/7369059

Use portable ReadDirent, not linux Getdents.

R=gri
TBR=gri
CC=golang-dev
https://golang.org/cl/7405051

ssadump:
- permit naming a package (not just *.go files) on command line.
- set BuildSerially flag when setting Log* flags
  (Q. should instead the logging functions take a lock?)

Builder:
- fixed bug when calling variadic function with zero '...'-params.
  Added regression test.

interp:
- more external functions:
   the 'error' interface
   bytes.{Equal,IndexByte}
   reflect.(Value).{Bool,NumOut,Out}
   syscall.{Close,Fstat,Read,Open,Stat,Lstat,Fstat,
     Getdents,ParseDirents,Getwd}
- permit comparisons between *Function and *closure.

With this CL, ssadump can now interpret ssadump itself (!),
loading, parsing, typing, SSA-building, and running
println("Hello, World!").  While a fmt-based equivalent still
lacks some external routines, e.g. math/big, I think there are
diminishing returns in expanding the interpreter (and
debugging it is starting to feel like "Inception").

I'm pretty confident this package is now good enough for wider use.

R=gri
CC=golang-dev
https://golang.org/cl/7392053

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7392054

Add DialOpt. So we have:

func Dial(net, addr string) (Conn, error)
func DialTimeout(net, addr string, timeout time.Duration) (Conn, error)
func DialOpt(addr string, opts ...DialOption) (Conn, error)

DialTimeout (and Dial) are regrettable in retrospect. Maybe
in a future Go we'll be back down to one Dial, with DialOpt
becoming Dial.

DialOpt looks like:

c, err := net.DialOpt("google.com:80")  // tcp is default
c, err := net.DialOpt("google.com:80", net.Timeout(30 * time.Second))
c, err := net.DialOpt("google.com:80", net.TCPFastOpen())
c, err := net.DialOpt("google.com:80", net.LocalAddr(..))
c, err := net.DialOpt("google.com:53", net.Network("udp6"))

And then: (clustered in godoc)

type DialOption interface { /* private only */ }
  func Deadline(time.Time) DialOption
  func LocalAddr(Addr) DialOption
  func Network(string) DialOption
  func TCPFastOpen() DialOption
  func Timeout(time.Duration) DialOption

I'm pretty confident we could add Happy Eyeballs to this too.

Fixes #3097
Update #3610
Update #4842

R=golang-dev, r, dave, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7365049

add per-P cache of dead G's
add global runnable queue (not used for now)
add list of idle P's (not used for now)

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7397061

If all locals are optimized away, the type instructions would stay in the instruction stream. Call fixautoused to scrub the output.

Fixes #4915.

R=rsc
CC=golang-dev
https://golang.org/cl/7385055

The values for the planet masses are given in
earth mass, not solar mass.

R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/7368054

Update #3362

R=golang-dev, adg, rsc
CC=golang-dev
https://golang.org/cl/7369055

While submitting CL 7371051 I accidentally reverted much of CL
7395052.  This change restores it.

R=gri
TBR=gri
CC=golang-dev
https://golang.org/cl/7364051

R=rsc
CC=golang-dev
https://golang.org/cl/7383054