Fixes #7627.

CL 61970044 changed the order in which .a files are passed to gccgo's link phase. However by reversing the order it caused gccgo to complain if both internal (liba.a) and external (liba_test.a) versions of a package were presented as the former would not contain all the necessary symbols, and the latter would duplicate symbols already defined.

This change ensures that all 'fake' targets remain at the top of the final link order which should be fine as a package compiled as an external test is a superset of its internal sibling.

Looking at how gcToolchain links tests I think this change now accurately mirrors those actions which present $WORK/_test before $WORK in the link order.

LGTM=iant
R=rsc, iant
CC=golang-codereviews, michael.hudson
https://golang.org/cl/80300043

Makes gc -x better.

LGTM=r
R=golang-codereviews, bradfitz, r
CC=golang-codereviews
https://golang.org/cl/73090043

LGTM=aram, rsc
R=aram, adg, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/74750045

Almost all TODOS, but the structure is there and it has the details
from go1.3.txt, which is hereby deleted.

LGTM=dominik.honnef, adg
R=golang-codereviews, dominik.honnef, adg
CC=golang-codereviews
https://golang.org/cl/80240044

If someone configures a 'textwidth' in go files, vim will by default insert
newlines into long lines as you type, which breaks syntax and doesn't really
make sense for go code. This fixes the default.

LGTM=dsymonds
R=golang-codereviews, gobot, dsymonds
CC=golang-codereviews
https://golang.org/cl/76890046

LGTM=adg
R=adg
CC=golang-codereviews
https://golang.org/cl/80310043

Some platform that implements inp_localgroup-like shared internet
protocol control block group looks a bit sensitive about transport
layer protocol's address:port reuse. Sometimes it rejects a TCP SYN
packet using TCP RST, and sometimes silence.

For now, until test case refactoring, we admit few Dial failures on
TestTCPConcurrentAccept as a workaround.

Update #7400
Update #7541

LGTM=jsing
R=jsing
CC=golang-codereviews
https://golang.org/cl/75920043

The previous fix CL 69340044 still leaves a possibility of it.
This CL prevents the kernel, especially DragonFly BSD, from
performing unpredictable asynchronous connection establishment
on stream-based transport layer protocol sockets.

Update #7541
Update #7474

LGTM=jsing
R=jsing
CC=golang-codereviews
https://golang.org/cl/75930043

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/80250043

LGTM=josharian
R=golang-codereviews, josharian
CC=golang-codereviews
https://golang.org/cl/80220043

Fixes windows/amd64 build.

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/79470046

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/79890046

Disable it until it's debugged so it doesn't hide other real
problems on Windows. The test was known to be unreliable
anyway (which is why it only needed 1 of 20 runs to pass), but
apparently it never passes on Windows. Figure out why later.

Update #7634

LGTM=alex.brainman
R=adg, alex.brainman
CC=golang-codereviews
https://golang.org/cl/80110043

See http://golang.org/s/go13heapdump for the file format.

LGTM=rsc
R=rsc, bradfitz, dvyukov, khr
CC=golang-codereviews
https://golang.org/cl/37540043

TBR=rsc
CC=golang-codereviews
https://golang.org/cl/80090043

Change two-bit stack map entries to encode:
0 = dead
1 = scalar
2 = pointer
3 = multiword

If multiword, the two-bit entry for the following word encodes:
0 = string
1 = slice
2 = iface
3 = eface

That way, during stack scanning we can check if a string
is zero length or a slice has zero capacity.  We can avoid
following the contained pointer in those cases.  It is safe
to do so because it can never be dereferenced, and it is
desirable to do so because it may cause false retention
of the following block in memory.

Slice feature turned off until issue 7564 is fixed.

Update #7549

LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/76380043

The existing code did not have a clear notion of whether
memory has been actually reserved.  It checked based on
whether in 32-bit mode or 64-bit mode and (on GNU/Linux) the
requested address, but it confused the requested address and
the returned address.

LGTM=rsc
R=rsc, dvyukov
CC=golang-codereviews, michael.hudson
https://golang.org/cl/79610043

This the second part of making persistent HTTPS connections to
certain servers (notably Amazon) robust.

See the story in part 1: https://golang.org/cl/76400046/

This is the http Transport change that notes whether our
net.Conn.Read has ever seen an EOF. If it has, then we use
that as an additional signal to not re-use that connection (in
addition to the HTTP response headers)

Fixes #3514

LGTM=rsc
R=agl, rsc
CC=golang-codereviews
https://golang.org/cl/79240044

Update #3514

An io.Reader is permitted to return either (n, nil)
or (n, io.EOF) on EOF or other error.

The tls package previously always returned (n, nil) for a read
of size n if n bytes were available, not surfacing errors at
the same time.

Amazon's HTTPS frontends like to hang up on clients without
sending the appropriate HTTP headers. (In their defense,
they're allowed to hang up any time, but generally a server
hangs up after a bit of inactivity, not immediately.) In any
case, the Go HTTP client tries to re-use connections by
looking at whether the response headers say to keep the
connection open, and because the connection looks okay, under
heavy load it's possible we'll reuse it immediately, writing
the next request, just as the Transport's always-reading
goroutine returns from tls.Conn.Read and sees (0, io.EOF).

But because Amazon does send an AlertCloseNotify record before
it hangs up on us, and the tls package does its own internal
buffering (up to 1024 bytes) of pending data, we have the
AlertCloseNotify in an unread buffer when our Conn.Read (to
the HTTP Transport code) reads its final bit of data in the
HTTP response body.

This change makes that final Read return (n, io.EOF) when
an AlertCloseNotify record is buffered right after, if we'd
otherwise return (n, nil).

A dependent change in the HTTP code then notes whether a
client connection has seen an io.EOF and uses that as an
additional signal to not reuse a HTTPS connection. With both
changes, the majority of Amazon request failures go
away. Without either one, 10-20 goroutines hitting the S3 API
leads to such an error rate that empirically up to 5 retries
are needed to complete an API call.

LGTM=agl, rsc
R=agl, rsc
CC=golang-codereviews
https://golang.org/cl/76400046

The nproc and ndone fields are uint32.  This makes the type
consistent.

LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews
https://golang.org/cl/79340044

Strictly speaking, it's not necessary in example_test.go, as the
Rows.Close docs say that "If Next returns false, the Rows are closed
automatically". However, if the for loop breaks or returns early, it's
not obvious that you'll leak unless you explicitly call Rows.Close.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews, rsc
https://golang.org/cl/79330043

Structured Exception Handling (SEH) was the first way to handle
exceptions (memory faults, divides by zero) on Windows.
The S might as well stand for "stack-based": the implementation
interprets stack addresses in a few different ways, and it gets
subtly confused by Go's management of stacks. It's also something
that requires active maintenance during cgo switches, and we've
had bugs in that maintenance in the past.

We have recently come to believe that SEH cannot work with
Go's stack usage. See http://golang.org/issue/7325 for details.

Vectored Exception Handling (VEH) is more like a Unix signal
handler: you set it once for the whole process and forget about it.

This CL drops all the SEH code and replaces it with VEH code.
Many special cases and 7 #ifdefs disappear.

VEH was introduced in Windows XP, so Go on windows/386 will
now require Windows XP or later. The previous requirement was
Windows 2000 or later. Windows 2000 immediately preceded
Windows XP, so Windows 2000 is the only affected version.
Microsoft stopped supporting Windows 2000 in 2010.
See http://golang.org/s/win2000-golang-nuts for details.

Fixes #7325.

LGTM=alex.brainman, r
R=golang-codereviews, alex.brainman, stephen.gutekanst, dave
CC=golang-codereviews, iant, r
https://golang.org/cl/74790043

This has come up twice now. Redirect future questions
to the explanation in the issue tracker.

LGTM=iant, r
R=r, iant
CC=golang-codereviews
https://golang.org/cl/79550043

Currently it's always zero, but that is inconsistent with math.Pow
and also plain wrong.
This is a proposal for how it should be defined.
Fixes #7583.

LGTM=rsc
R=golang-codereviews, iant, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/76940044

Fixes #7252.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/77990044

Fixes #7488.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/78050043

This rule not existing has been the source of many discussions
on golang-dev and on issues. We have stated publicly that it is
true, but we have never written it down. Write it down.

Fixes #6242.

LGTM=r, dan.kortschak, iant, dvyukov
R=golang-codereviews, r, dominik.honnef, dvyukov, dan.kortschak, iant, 0xjnml
CC=golang-codereviews
https://golang.org/cl/75130045

Fixes #6403

LGTM=rsc
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/72840044

ReadFrom should not return until it receives a non-nil error
or too many contiguous (0, nil)s from a given reader.
Currently it immediately returns if it receives one (0, nil).
Fixes #7611.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/76400048

Fixes #6902

LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/78730049

bi is a slice and not an array, so bi[:] does not make much sense.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/79280043

LGTM=josharian, dan.kortschak
R=golang-codereviews, josharian, dan.kortschak
CC=golang-codereviews
https://golang.org/cl/75080043

It's a little bit waste to check if r is not a surrogate
code point because RuneError is not a surrogate code point.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/79230043

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/79080044

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/79120043

"min" and "max" in "case '{'" clause are fresh variables.
The variables defined in the outer scope never get value
other than 0.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/78750044

Currently Scan ignores an error returned from source if the number
of bytes source has read is 0.

Fixes #7594.

LGTM=gri
R=golang-codereviews, bradfitz, gri
CC=golang-codereviews
https://golang.org/cl/78120043

warning: src/cmd/ld/macho.c:595 sign-extended character constant
warning: src/cmd/ld/macho.c:595 sign-extended character constant
warning: src/cmd/ld/symtab.c:63 sign-extended character constant
warning: src/cmd/ld/symtab.c:63 sign-extended character constant

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/76580046

LGTM=dvyukov
R=dvyukov
CC=golang-codereviews
https://golang.org/cl/78410043

Fixes issue #6976.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/72080044