Fixes #8023.

LGTM=rsc
R=r, iant, ken, rsc
CC=golang-codereviews
https://golang.org/cl/98340043

Discussion here: https://golang.org/cl/100490044/#msg14

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/98350043

Fixes #8010.

LGTM=bradfitz, khr
R=khr, bradfitz, dvyukov
CC=golang-codereviews
https://golang.org/cl/91450048

Currently freeOSMemory makes only marking phase of GC, but not sweeping phase.
So recently memory is not released after freeOSMemory.
Do both marking and sweeping during freeOSMemory.
Fixes #8019.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, rsc
https://golang.org/cl/97550043

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/94610043

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/92440043

Rename Seek to seek in asm file, was overlooked in CL 99320043.

LGTM=bradfitz, r
R=r, rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/99320044

Accidental change from fixing Content-Length on 204s
in http://golang.org/issue/6685 earlier.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/92400047

LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews
https://golang.org/cl/93420046

LGTM=r
R=golang-codereviews, aram, 0intro, gobot, r
CC=golang-codereviews
https://golang.org/cl/100490044

Found by go vet.

LGTM=crawshaw
R=golang-codereviews, crawshaw
CC=golang-codereviews
https://golang.org/cl/100510044

Fixes #8007.

LGTM=r
R=gri, r
CC=golang-codereviews
https://golang.org/cl/91510044

TBR=rsc

TBR=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/100500047

These functions claimed to return error (an interface)
and be implemented entirely in assembly, but it's not
possible to create an interface from assembly
(at least not easily).

In reality the functions were written to return an errno uintptr
despite the Go prototype saying error.
When the errno was 0, they coincidentally filled out a nil error
by writing the 0 to the type word of the interface.
If the errno was ever non-zero, the functions would
create a non-nil error that would crash when trying to
call err.Error().

Luckily these functions (Seek, Time, Gettimeofday) pretty
much never fail, so it was all kind of working.

Found by go vet.

LGTM=bradfitz, r
R=golang-codereviews, bradfitz, r
CC=golang-codereviews
https://golang.org/cl/99320043

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/98290048

Update #7947.

LGTM=iant
R=rsc, iant
CC=golang-codereviews
https://golang.org/cl/91500044

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/93430044

TestLargeDefs was issuing over one million small writes to
create a 7MB file (large.go). This is quite slow on Plan 9
since our disk file systems aren't very fast and they're
usually accessed over the network.

Buffering the writes makes the test about six times faster.
Even on Linux, it's about 1.5 times faster.

Here are the results on a slow Plan 9 machine:

Before:
        % ./pack.test -test.v -test.run TestLargeDefs
        === RUN TestLargeDefs
        --- PASS: TestLargeDefs (125.11 seconds)
        PASS

After:
        % ./pack.test -test.v -test.run TestLargeDefs
        === RUN TestLargeDefs
        --- PASS: TestLargeDefs (20.835 seconds)
        PASS

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/95040044

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/95490043

The introduction of temporaries in order.c was not
quite right for two corner cases:

1) The rewrite that pushed new variables on the lhs of
a receive into the body of the case was dropping the
declaration of the variables. If the variables escape,
the declaration is what allocates them.
Caught by escape analysis sanity check.
In fact the declarations should move into the body
always, so that we only allocate if the corresponding
case is selected. Do that. (This is an optimization that
was already present in Go 1.2. The new order code just
made it stop working.)

Fixes #7997.

2) The optimization to turn a single-recv select into
an ordinary receive assumed it could take the address
of the destination; not so if the destination is _.

Fixes #7998.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/100480043

Calling tar.Reader.Read() used to work fine, but without this patch it panics.
Simply return EOF to indicate the tar.Reader.Next() needs to be called.

LGTM=iant, bradfitz
R=golang-codereviews, bradfitz, iant, mikioh.mikioh, dominik.honnef
CC=golang-codereviews
https://golang.org/cl/94530043

This CL restores dropped constants not supported in OpenBSD 5.5
and tris to keep the promise of API compatibility.

Update #7049

LGTM=jsing, bradfitz
R=rsc, jsing, bradfitz
CC=golang-codereviews
https://golang.org/cl/94950043

This CL restores dropped constants not supported in OpenBSD 5.5
and tris to keep the promise of API compatibility.

Update #7049

LGTM=jsing, bradfitz, rsc
R=rsc, jsing, robert.hencke, minux.ma, bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/96970043

- use Init to establish heap invariant on
  a non-empty heap
- use Fix to update heap after an element's
  properties have been changed

(The old code used Init where it wasn't needed,
 and didn't use Fix because Fix was added after
 the example was written.)

LGTM=bradfitz
R=adonovan, bradfitz
CC=golang-codereviews
https://golang.org/cl/94520043

for GOOS in darwin freebsd linux nacl netbsd openbsd plan9 solaris windows
do
        for GOARCH in 386 amd64 amd64p32 arm
        do
                go vet
        done
done

These are all real mistakes being corrected, but none
of them should be able to cause problems today
due to the NOSPLIT on the functions.

However, vet has also identified a few important problems.
I'm sending this CL to get rid of the trivial 'go vet' results
before attacking the real ones.

LGTM=r
R=golang-codereviews, r, bradfitz
CC=golang-codereviews
https://golang.org/cl/95460046

None of these are real bugs.
The variable name in the reference is not semantically meaningful,
except that 'go vet' will double check the offset against the name for you.

The stack sizes being corrected really are incorrect but they are also
in NOSPLIT functions so they typically don't matter.

Found by vet.

GOOS=linux GOARCH=amd64 go vet sync/atomic
GOOS=linux GOARCH=amd64p32 go vet sync/atomic
GOOS=linux GOARCH=386 go vet sync/atomic
GOOS=linux GOARCH=arm go vet sync/atomic
GOOS=freebsd GOARCH=arm go vet sync/atomic
GOOS=netbsd GOARCH=arm go vet sync/atomic

LGTM=r
R=r, bradfitz
CC=golang-codereviews
https://golang.org/cl/100500043

The vet check is in CL 10470044.

LGTM=bradfitz, r
R=r, bradfitz
CC=golang-codereviews
https://golang.org/cl/91480044

The GC program describing a data structure sometimes trusts the
pointer base type and other times does not (if not, the garbage collector
must fall back on per-allocation type information stored in the heap).
Make the scanning of a pointer in an interface do the same.
This fixes a crash in a particular use of reflect.SliceHeader.

Fixes #8004.

LGTM=khr
R=golang-codereviews, khr
CC=0xe2.0x9a.0x9b, golang-codereviews, iant, r
https://golang.org/cl/100470045

LGTM=ruiu
R=golang-codereviews, ruiu
CC=golang-codereviews
https://golang.org/cl/91480043

Globals, function arguments, and results are special cases in
registerization.

Globals must be flushed aggressively, because nearly any
operation can cause a panic, and the recovery code must see
the latest values. Globals also must be loaded aggressively,
because nearly any store through a pointer might be updating a
global: the compiler cannot see all the "address of"
operations on globals, especially exported globals. To
accomplish this, mark all globals as having their address
taken, which effectively disables registerization.

If a function contains a defer statement, the function results
must be flushed aggressively, because nearly any operation can
cause a panic, and the deferred code may call recover, causing
the original function to return the current values of its
function results. To accomplish this, mark all function
results as having their address taken if the function contains
any defer statements. This causes not just aggressive flushing
but also aggressive loading. The aggressive loading is
overkill but the best we can do in the current code.

Function arguments must be considered live at all safe points
in a function, because garbage collection always preserves
them: they must be up-to-date in order to be preserved
correctly. Accomplish this by marking them live at all call
sites. An earlier attempt at this marked function arguments as
having their address taken, which disabled registerization
completely, making programs slower. This CL's solution allows
registerization while preserving safety. The benchmark speedup
is caused by being able to registerize again (the earlier CL
lost the same amount).

benchmark                old ns/op     new ns/op     delta
BenchmarkEqualPort32     61.4          56.0          -8.79%

benchmark                old MB/s     new MB/s     speedup
BenchmarkEqualPort32     521.56       570.97       1.09x

Fixes #1304. (again)
Fixes #7944. (again)
Fixes #7984.
Fixes #7995.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, iant, r
https://golang.org/cl/97500044

Do not compare nil and true.

Fixes #7996.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/91470043

The function takes 32 bytes of arguments: 8 for the *block
and then 3*8 for the slice.

The 24 is not causing a bug (today at least) because the
final word is the cap of the slice, which the assembly
does not use.

Identified by 'go vet std'.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/96360043

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/100440045

Fixes #7406.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/97440043

fixes windows build

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/97500043

Turns out elf.File.Sections is indexed by the actual
section number, not the number minus one.
I don't know why I thought the -1 was necessary.

Fixes objdump test (and therefore build) on ELF systems.

While we're here, fix bounds on gnuDump so that we
don't crash when asked to disassemble outside
the text segment. May fix Windows build or at least
make the failure more interesting.

TBR=iant
CC=golang-codereviews
https://golang.org/cl/92390043

Implement the changes as suggested by rsc.
Fixes #6670.

LGTM=josharian, iant
R=golang-codereviews, iant, josharian, mikioh.mikioh, alex, gobot
CC=golang-codereviews, rsc
https://golang.org/cl/83690045

There is some duplication here with cmd/nm.
There is a TODO to address that after 1.3 is out.

Update #7452

x86 disassembly works and is tested.

The arm disassembler does not exist yet
and is therefore not yet hooked up.

LGTM=crawshaw, iant
R=crawshaw, iant
CC=golang-codereviews
https://golang.org/cl/91360046

The x86 disassembler lives in rsc.io/x86/x86asm for now.
We need to figure out what should live where in the long term,
but not before the 1.3 release.

The completed code reviews for the disassembler are at:
https://golang.org/cl/95350044
https://golang.org/cl/95300044
https://golang.org/cl/97100047
https://golang.org/cl/93110044
https://golang.org/cl/99000043
https://golang.org/cl/98990043

LGTM=crawshaw
R=crawshaw, jacek.masiulaniec
CC=golang-codereviews
https://golang.org/cl/92360043

Generated by addca.

R=gobot
CC=golang-codereviews
https://golang.org/cl/92380043