The sticking point on 386 has been the "PC relative" relocations
used to point the garbage collection metadata at the type info.
These aren't in the code segment, and I don't trust that the linker
isn't doing something special that would be okay in code but
not when interpreting the pointers as data (for example, a PLT
jump table would be terrible).

Solve the problem in two steps:

1. Handle "PC relative" relocations within a section internally,
so that the external linker never sees them.

2. Move the gcdata and gcbss tables into the rodata section,
where the type information lives, so that the relocations can
be handled internally.

(To answer the obvious question, we make the gc->type
references relative so that they need not be relocated
individually when generating a shared object file.)

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7629043

For  better printing, I recently changed Name to return "<unnamed>" for templates
with empty names, but this causes trouble for the many packages that used "" as
the template name, so restore the old behavior.
It's usually printed as a quoted string anyway, so it should be fine.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/7577044

Fixes #4981.

R=bradfitz, fullung, rsc, minux.ma
CC=golang-dev
https://golang.org/cl/7474047

The information was missing, oddly enough.

R=golang-dev, rsc, iant
CC=golang-dev
https://golang.org/cl/7636044

Also rename the relevant examples and make sure the working one compiles.

R=golang-dev, bradfitz, adg, iant, rsc
CC=golang-dev
https://golang.org/cl/7597043

Fixes #4902

R=golang-dev, alex.brainman, r, google
CC=golang-dev
https://golang.org/cl/7579045

Otherwise the next goroutine run on the m
can get inadvertently locked if it executes a cgo call
that turns on the internal lock.

While we're here, fix the cgo panic unwind to
decrement m->ncgo like the non-panic unwind does.

Fixes #4971.

R=golang-dev, iant, dvyukov
CC=golang-dev
https://golang.org/cl/7627043

Have seen failures with GOMAXPROCS=4 on Windows.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7626043

Before this CL, running

        cd misc/cgo/test
        go test -c
        readelf --dyn-syms test.test | grep cgoexp

turned up many UNDEF symbols corresponding to symbols actually
in the binary but marked only cgo_export_static. Only symbols
marked cgo_export_dynamic should be listed in this mode.
And if the symbol is going to be listed, it should be listed with its
actual address instead of UNDEF.

The Linux dynamic linker didn't care about the seemingly missing
symbols, but the BSD one did.

This CL eliminates the symbols from the dyn-syms table.

R=golang-dev
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/7624043

Fixes #4905.

R=rsc, r, iant, ken
CC=golang-dev
https://golang.org/cl/7583043

- Introduce MaxAlign constant and use in data layout
and ELF section header.

- Allow up to 16-byte alignment for large objects
(will help Keith's hash changes).

- Emit ELF symbol for .rathole (global /dev/null used by 8c).

- Invoke gcc with -m32/-m64 as appropriate.

- Don't invoke gcc if writing the .o file failed.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7563045

Now the default startup is that the program begins at _rt0_386_$GOOS,
which behaves as if calling main(argc, argv). Main jumps to _rt0_386.

This makes the _rt0_386 entry match the expected semantics for
the standard C "main" function, which we can now provide for use when
linking against a standard C library.

386 analogue of https://golang.org/cl/7525043

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7551045

Implement what Chrome calls socket "late binding". See:
https://insouciant.org/tech/connection-management-in-chromium/

In a nutshell, if our HTTP client needs a TCP connection to a
remote host and there's not an idle one available, rather than
kick off a dial and wait for that specific dial, we instead
kick off a dial and wait for either our own dial to finish, or
any other TCP connection to that same host to become
available.

The implementation looks like a classic "Learning Go
Concurrency" slide.

Chrome's commit and numbers:
http://src.chromium.org/viewvc/chrome?view=rev&revision=36230

R=golang-dev, daniel.morsing, adg
CC=golang-dev
https://golang.org/cl/7587043

Change 231af8ac63aa (CL 7314062) made runtime.enteryscall()
set m->mcache = nil, which means that we can no longer use
syscall.errstr in syscall.Syscall and syscall.Syscall6, since it
requires a new buffer to be allocated for holding the error string.
Instead, we use pre-allocated per-M storage to hold error strings
from syscalls made while in entersyscall mode, and call
runtime.findnull to calculate the lengths.

Fixes #4994.

R=rsc, rminnich, ality, dvyukov, rminnich, r
CC=golang-dev
https://golang.org/cl/7567043

This CL splits multicast listener tests into two; for IPv4 and
for IPv6. It also removes redundant test inputs and makes sure
that assignment of multicast interface to stablize the tests.

Fixes #4059.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7565043

Instructions for use in AES hashing.  See CL#7543043

R=rsc
CC=golang-dev
https://golang.org/cl/7548043

The code would violate the contract of cmp64.

Fixes #5002.

R=rsc, golang-dev
CC=golang-dev
https://golang.org/cl/7593043

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7595043

TBR=golang-dev
CC=golang-dev
https://golang.org/cl/7575046

R=adonovan, bradfitz
CC=golang-dev
https://golang.org/cl/7492045

    Instead of relying on gofmt's diff output (which is a unified
    diff), we manually invoke diff -n and produce an RCS format diff,
    which can easily be parsed in Emacs, with the go--apply-rcs-patch
    function.

    This fixes undocumented issues with the old implementation such as
    skipping over hunks of changes, and it fixes the documented issue
    of not being able to handle file names that include whitespace.

    It can also apply the patch on a buffer that has no file name
    attached at all.

    Last but not least, it greatly simplifies the gofmt function
    itself.

Fixes #4766.
Fixes #4475.

R=adonovan, cw, patrick.allen.higgins, sameer
CC=golang-dev
https://golang.org/cl/7516046

Move pollServer from fd_unix.go to fd_poll_unix.go.
Add pollServerInit(*NetFD) to allow custom initialization.
Add pollServer.Close(*NetFD) to allow custom finalization.
Move setDeadline() to fd_poll_unix.go to allow custom handling of deadlines.
Move newPollServer() to fd_poll_unix.go to allow custom initialization.
No logical code changes.
The next step will be to turn off fd_poll_unix.go for some platform
(I have changes for darwin/linux) and redirect it into runtime. See:
https://golang.org/cl/7569043/diff/2001/src/pkg/net/fd_poll_runtime.go

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7513045

The deadlock episodically occurs on misc/cgo/test/TestCthread.
The problem is that starttheworld() leaves some P's with local work
without M's. Then all active M's enter into syscalls, but reject to
wake another M's due to the following check (both in entersyscallblock() and in retake()):
if(p->runqhead == p->runqtail &&
        runtime·atomicload(&runtime·sched.nmspinning) +
        runtime·atomicload(&runtime·sched.npidle) > 0)
        continue;

R=rsc
CC=golang-dev
https://golang.org/cl/7424054

Still to do: non-linux and non-amd64.
It may work on other ELF-based amd64 systems too, but untested.

"go test -ldflags -hostobj $GOROOT/misc/cgo/test" passes.

Much may yet change, but this seems a reasonable checkpoint.

R=iant
CC=golang-dev
https://golang.org/cl/7369057

Fixes #4955.

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/7563043

Ensure that accept/connect respect deadline,
even if the operation can be executed w/o blocking.
Note this changes external behavior, but it makes
it consistent with read/write.
Factor out deadline check into pollServer.PrepareRead/Write,
in preparation for edge triggered pollServer.
Ensure that pollServer.WaitRead/Write are not called concurrently
by adding rio/wio locks around connect/accept.

R=golang-dev, mikioh.mikioh, bradfitz, iant
CC=golang-dev
https://golang.org/cl/7436048

R=golang-dev, akumar
CC=golang-dev
https://golang.org/cl/7523044

R=golang-dev, akumar
CC=golang-dev
https://golang.org/cl/7564043

Fixes #4505.

R=golang-dev, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/7468043

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/7551043

Fixes #4982.

R=adonovan, r
CC=golang-dev
https://golang.org/cl/7537043

Also:
- cleaner handling of constants w/ unknown value
- removed several TODOs

R=adonovan
CC=golang-dev
https://golang.org/cl/7473043

Fixes #4974.

R=rsc, bradfitz, r
CC=golang-dev
https://golang.org/cl/7545043

It's a common mistake to build a recursive String method; explain it well and
show how to avoid it.

R=golang-dev, bradfitz, adg
CC=golang-dev
https://golang.org/cl/7486049

See also https://golang.org/cl/7520044

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7533044

Before:
BenchmarkHeaderWriteSubset  500000  2354 ns/op  197 B/op  2 allocs/op
After:
BenchmarkHeaderWriteSubset 1000000  2085 ns/op    0 B/op  0 allocs/op

Fixes #3761

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7508043

Also emit cgo_ldflag pragmas.

R=golang-dev, remyoudompheng, iant
CC=golang-dev
https://golang.org/cl/7530043

TBR=bradfitz
CC=golang-dev
https://golang.org/cl/7540043

TBR=golang-dev
CC=golang-dev
https://golang.org/cl/7539043

Some IDS somewhere thinks "Go http package" is a virus.
Make it something else for Go 1.1. Dumb but easy.

R=golang-dev, bradfitz, minux.ma
CC=golang-dev
https://golang.org/cl/7532043