With gccgo some operating systems require using select rather
than epoll or kevent.  Using select means that we have to wake
up the polling thread each time we add a new file descriptor.
This implements that in the generic code rather than adding
another wakeup channel, even though nothing in the current net
package uses the capability.

R=rsc, iant2
CC=golang-dev
https://golang.org/cl/4284069

NewPackage creates an ast.Package node from
a set of package files and resolves unresolved
identifiers.

Also:
- Changed semantics of Scope.Insert: If an
  object is inserted w/o errors, the result
  is nil (before it was obj).
- Fixed an identifier resolution bug in the
  parser: map keys must not be resolved.

gotype runs through several go/* packages
and successfully resolves all (non-field/method)
identifiers.

R=rog, rsc
CC=golang-dev
https://golang.org/cl/4298044

This speeds up strings.ToLower, etc.

before/after:
strings_test.BenchmarkMapNoChanges 1000000 1013 ns/op
strings_test.BenchmarkMapNoChanges 5000000  442 ns/op

R=r, rog, eh, rsc
CC=golang-dev
https://golang.org/cl/4306056

in gdb, 'info goroutines' and 'goroutine <n> <cmd> were crashing
because the 'g' and 'm' structures had changed a bit.

R=rsc
CC=golang-dev
https://golang.org/cl/4289077

R=r
CC=golang-dev
https://golang.org/cl/4313051

bug323.go:18:3: error: reference to undefined field or method ‘Meth’
bug323.go:19:3: error: reference to undefined field or method ‘Meth2’

R=golang-dev, rsc1
CC=golang-dev
https://golang.org/cl/4280072

R=adg
CC=golang-dev
https://golang.org/cl/4289076

On darwin amd64 it was impossible to create more that ~132 threads. While
investigating I noticed that go consumes almost 1TB of virtual memory per
OS thread and the reason for such a small limit of OS thread was because
process was running out of virtual memory. While looking at bsdthread_create
I noticed that on amd64 it wasn't using PTHREAD_START_CUSTOM.
If you look at http://fxr.watson.org/fxr/source/bsd/kern/pthread_synch.c?v=xnu-1228
you will see that in that case darwin will use stack pointer as stack size,
allocating huge amounts of memory for stack. This change fixes the issue
and allows for creation of up to 2560 OS threads (which appears to be some
Mac OS X limit) with relatively small virtual memory consumption.

R=rsc
CC=golang-dev
https://golang.org/cl/4289075

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/4316042

bug325.go:13:10: error: invalid indirect of ‘unsafe.Pointer’
bug325.go:14:31: error: reference to field ‘foo’ in object which has no fields or methods

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4313050

R=rsc
CC=golang-dev
https://golang.org/cl/4314044

init.go:16:10: error: invalid reference to unexported identifier ‘runtime.init’
init.go:15:2: error: reference to undefined name ‘init’
init.go:17:10: error: reference to undefined name ‘init’

R=golang-dev, rsc1
CC=golang-dev
https://golang.org/cl/4289074

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4279074

It's been six months.

R=rsc
CC=golang-dev
https://golang.org/cl/4289073

R=rsc
CC=golang-dev
https://golang.org/cl/4275076

cmp6.go:28:9: error: incompatible types in binary expression
cmp6.go:29:9: error: incompatible types in binary expression
cmp6.go:40:9: error: incompatible types in binary expression
cmp6.go:41:9: error: incompatible types in binary expression
cmp6.go:48:9: error: expected integer, floating, complex, string, pointer, boolean, interface, slice, map, channel, or function type

R=rsc, r2
CC=golang-dev
https://golang.org/cl/4281071

These are the top runners.  More to come.
Also print two digits of timing info under -test.v.

R=rsc
CC=golang-dev
https://golang.org/cl/4317044

bug081.go:9:9: error: expected type

R=rsc
CC=golang-dev
https://golang.org/cl/4280071

R=adg, rsc, ality
CC=golang-dev
https://golang.org/cl/4281069

New make target "testshort" runs "gotest -test.short" and is invoked
by run.bash, which is invoked by all.bash.

Use -test.short to make one package (crypto ecdsa) run much faster.
More changes to come.

Once this is in, I will update the long-running tests to use the new flag.

R=rsc
CC=golang-dev
https://golang.org/cl/4317043

bug016.go:11:8: error: negative shift count

R=rsc, gri
CC=golang-dev
https://golang.org/cl/4312055

R=rsc
CC=golang-dev
https://golang.org/cl/4314042

R=rsc
CC=golang-dev
https://golang.org/cl/4298060

R=iant, rsc, brainman
CC=golang-dev
https://golang.org/cl/4306042

R=rsc
CC=golang-dev
https://golang.org/cl/4312054

bug274.go:23:3: error: missing statement after label
bug274.go:25:3: error: missing statement after label
bug274.go:28:3: error: label ‘L2’ defined and not used

R=rsc
CC=golang-dev
https://golang.org/cl/4273114

Fixes #1615.
This time for sure.

R=rsc, gri
CC=golang-dev
https://golang.org/cl/4275079

Fixes #1641.

Actually it side steps the real issue, which is that the
setitimer(2) implementation on OS X is not useful for
profiling of multi-threaded programs.  I filed the below
using the Apple Bug Reporter.

/*
Filed as Apple Bug Report #9177434.

This program creates a new pthread that loops, wasting cpu time.
In the main pthread, it sleeps on a condition that will never come true.
Before doing so it sets up an interval timer using ITIMER_PROF.
The handler prints a message saying which thread it is running on.

POSIX does not specify which thread should receive the signal, but
in order to be useful in a user-mode self-profiler like pprof or gprof
   http://code.google.com/p/google-perftools
   http://www.delorie.com/gnu/docs/binutils/gprof_25.html
it is important that the thread that receives the signal is the one
whose execution caused the timer to expire.

Linux and FreeBSD handle this by sending the signal to the process's
queue but delivering it to the current thread if possible:

   http://lxr.linux.no/linux+v2.6.38/kernel/signal.c#L802
     807        /*
     808         * Now find a thread we can wake up to take the signal off the queue.
     809         *
     810         * If the main thread wants the signal, it gets first crack.
     811         * Probably the least surprising to the average bear.
     812         * /

   http://fxr.watson.org/fxr/source/kern/kern_sig.c?v=FREEBSD8;im=bigexcerpts#L1907
     1914         /*
     1915          * Check if current thread can handle the signal without
     1916          * switching context to another thread.
     1917          * /

On those operating systems, this program prints:

    $ ./a.out
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    signal on cpu-chewing looper thread
    $

The OS X kernel does not have any such preference.  Its get_signalthread
does not prefer current_thread(), in contrast to the other two systems,
so the signal gets delivered to the first thread in the list that is able to
handle it, which ends up being the main thread in this experiment.
http://fxr.watson.org/fxr/source/bsd/kern/kern_sig.c?v=xnu-1456.1.26;im=excerpts#L1666

    $ ./a.out
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    signal on sleeping main thread
    $

The fix is to make get_signalthread use the same heuristic as
Linux and FreeBSD, namely to use current_thread() if possible
before scanning the process thread list.

*/

#include <sys/time.h>
#include <sys/signal.h>
#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

static void handler(int);
static void* looper(void*);

static pthread_t pmain, ploop;

int
main(void)
{
        struct itimerval it;
        struct sigaction sa;
        pthread_cond_t cond;
        pthread_mutex_t mu;

        memset(&sa, 0, sizeof sa);
        sa.sa_handler = handler;
        sa.sa_flags = SA_RESTART;
        memset(&sa.sa_mask, 0xff, sizeof sa.sa_mask);
        sigaction(SIGPROF, &sa, 0);

        pmain = pthread_self();
        pthread_create(&ploop, 0, looper, 0);

        memset(&it, 0, sizeof it);
        it.it_interval.tv_usec = 10000;
        it.it_value = it.it_interval;
        setitimer(ITIMER_PROF, &it, 0);

        pthread_mutex_init(&mu, 0);
        pthread_mutex_lock(&mu);

        pthread_cond_init(&cond, 0);
        for(;;)
                pthread_cond_wait(&cond, &mu);

        return 0;
}

static void
handler(int sig)
{
        static int nsig;
        pthread_t p;

        p = pthread_self();
        if(p == pmain)
                printf("signal on sleeping main thread\n");
        else if(p == ploop)
                printf("signal on cpu-chewing looper thread\n");
        else
                printf("signal on %p\n", (void*)p);
        if(++nsig >= 10)
                exit(0);
}

static void*
looper(void *v)
{
        for(;;);
}

R=r
CC=golang-dev
https://golang.org/cl/4273113

label.go:30:1: error: label ‘L6’ already defined
label.go:28:1: note: previous definition of ‘L6’ was here
label.go:23:1: error: label ‘L4’ defined and not used
label.go:52:2: error: label ‘defalt’ defined and not used
label.go:17:1: error: label ‘L2’ defined and not used
label.go:26:1: error: label ‘L5’ defined and not used
label.go:20:1: error: label ‘L3’ defined and not used
label.go:14:1: error: label ‘L1’ defined and not used

label1.go:32:13: error: invalid continue label ‘L2’
label1.go:44:13: error: invalid continue label ‘L3’
label1.go:52:10: error: invalid break label ‘L4’
label1.go:55:13: error: invalid continue label ‘L4’
label1.go:65:9: error: invalid break label ‘L5’
label1.go:68:12: error: invalid continue label ‘L5’
label1.go:76:10: error: invalid break label ‘L1’
label1.go:79:13: error: invalid continue label ‘L1’

R=rsc
CC=golang-dev
https://golang.org/cl/4275078

Also fix comment.

The only caller of chanrecv initializes the value to false, so
this patch makes no difference at present.  But it seems like
the right thing to do.

R=rsc
CC=golang-dev
https://golang.org/cl/4312053

R=rsc
CC=golang-dev
https://golang.org/cl/4309049

R=r
CC=golang-dev
https://golang.org/cl/4280060

Fixes #1639

R=golang-dev, bradfitzgo
CC=golang-dev
https://golang.org/cl/4291069

R=adg, dfc, r
CC=golang-dev
https://golang.org/cl/4296042

R=golang-dev
CC=golang-dev
https://golang.org/cl/4276077

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/4273102

Correctly distinguish between lhs and rhs identifiers
and resolve/declare them accordingly.

Collect field and method names in respective scopes
(will be available after some minor AST API changes).

Also collect imports since it's useful to have that
list directly w/o having to re-traverse the AST
(will also be available after some minor AST API changes).

No external API changes in this CL.

R=rsc, rog
CC=golang-dev
https://golang.org/cl/4271061

Change M-x gofmt to display errors in a new buffer instead of
clobbering the current buffer.

Add gofmt-before-save, which runs gofmt when in go-mode.  This
can be used with before-save-hook.  Add to your .emacs:
  (add-hook 'before-save-hook 'gofmt-before-save)

R=rsc, aclements, amdragon
CC=golang-dev
https://golang.org/cl/4276059

The top level bytes.Buffer is always there and can be re-used.
Rpc goes from 83 to 79 mallocs per round trip.

R=rsc
CC=golang-dev
https://golang.org/cl/4271062

R=rsc
CC=golang-dev
https://golang.org/cl/4285063