go/printer: don't forget the .0 in 1.0

(use floating-point rather then integer constant division)

gofmt -w src misc

Fixes issue 3965.

R=r, bsiegert, 0xjnml
CC=bradfitz, golang-dev
http://codereview.appspot.com/6610051
doc/codewalk: make it work with jQuery 1.8.2
    so that it could work with the bundled jQuery.

R=adg
CC=golang-dev
http://codereview.appspot.com/6592073
runtime: mask SSE exceptions on plan9/amd64

The Go run-time assumes that all SSE floating-point exceptions
are masked so that Go programs are not broken by such invalid
operations. By default, the 64-bit version of the Plan 9 kernel
masks only some SSE floating-point exceptions. Here, we mask
them all on a per-thread basis.

R=rsc, rminnich, minux.ma
CC=golang-dev
http://codereview.appspot.com/6592056

Committer: Russ Cox <rsc@golang.org>
crypto/sha256, crypto/sha512: 1.3x speedup

SHA-256:

benchmark          old ns/op    new ns/op    delta
BenchmarkHash1K        21686        16912  -22.01%
BenchmarkHash8K       173216       135020  -22.05%

benchmark           old MB/s     new MB/s  speedup
BenchmarkHash1K        47.22        60.55    1.28x
BenchmarkHash8K        47.29        60.67    1.28x

SHA-512:

benchmark          old ns/op    new ns/op    delta
BenchmarkHash1K        14323        11163  -22.06%
BenchmarkHash8K       114120        88693  -22.28%

benchmark           old MB/s     new MB/s  speedup
BenchmarkHash1K        71.49        91.73    1.28x
BenchmarkHash8K        71.78        92.36    1.29x

R=golang-dev, agl
CC=golang-dev
http://codereview.appspot.com/6584071

Committer: Russ Cox <rsc@golang.org>
cmd/5g: fix out of registers in nested calls, add compiler torture test.

R=golang-dev, dave, daniel.morsing, rsc
CC=golang-dev, remy
http://codereview.appspot.com/6586072
cmd/5g: avoid temporary during constant OINDEX

func addr(s[]int) *int {
	return &s[2]
}

--- prog list "addr" ---
0000 (/home/dfc/src/addr.go:5) TEXT     addr+0(SB),$0-16
0001 (/home/dfc/src/addr.go:6) MOVW     $s+0(FP),R0
0002 (/home/dfc/src/addr.go:6) MOVW     4(R0),R1
0003 (/home/dfc/src/addr.go:6) MOVW     $2,R2
0004 (/home/dfc/src/addr.go:6) CMP      R2,R1,
0005 (/home/dfc/src/addr.go:6) BHI      ,7(APC)
0006 (/home/dfc/src/addr.go:6) BL       ,runtime.panicindex+0(SB)
0007 (/home/dfc/src/addr.go:6) MOVW     0(R0),R0
0008 (/home/dfc/src/addr.go:6) MOVW     $8,R1
0009 (/home/dfc/src/addr.go:6) ADD      R1,R0
0010 (/home/dfc/src/addr.go:6) MOVW     R0,.noname+12(FP)
0011 (/home/dfc/src/addr.go:6) RET      ,

becomes

--- prog list "addr" ---
0000 (/home/dfc/src/addr.go:5) TEXT     addr+0(SB),$0-16
0001 (/home/dfc/src/addr.go:6) MOVW     $s+0(FP),R0
0002 (/home/dfc/src/addr.go:6) MOVW     4(R0),R1
0003 (/home/dfc/src/addr.go:6) MOVW     $2,R2
0004 (/home/dfc/src/addr.go:6) CMP      R2,R1,
0005 (/home/dfc/src/addr.go:6) BHI      ,7(APC)
0006 (/home/dfc/src/addr.go:6) BL       ,runtime.panicindex+0(SB)
0007 (/home/dfc/src/addr.go:6) MOVW     0(R0),R0
0008 (/home/dfc/src/addr.go:6) ADD      $8,R0
0009 (/home/dfc/src/addr.go:6) MOVW     R0,.noname+12(FP)
0010 (/home/dfc/src/addr.go:6) RET      ,

R=rsc, remyoudompheng, minux.ma
CC=golang-dev
http://codereview.appspot.com/6590056
cmd/cc: map C int to int32 in Go defs

R=golang-dev, minux.ma, rsc
CC=golang-dev
http://codereview.appspot.com/6621052

Committer: Shenghou Ma <minux.ma@gmail.com>
test: Add rundir, rundircmpout and errorcheckdir commands to testlib and run.go

rundir will compile each file in the directory in lexicographic order, link the last file as the main package and run the resulting program. rundircmpout is an related command, that will compare the output of the program to an corresponding .out file

errorcheckdir will compile each file in a directory in lexicographic order, running errorcheck on each file as it compiles. All compilations are assumed to be successful except for the last file. However, If a -0 flag is present on the command, the last compilation will also be assumed successful

This CL also includes a small refactoring of run.go. It was getting unwieldy and the meaning of the run commands was hidden behind argument line formatting.

Fixes issue 4058.

R=rsc, minux.ma, remyoudompheng, iant
CC=golang-dev
http://codereview.appspot.com/6554071
pprof: add goroutine blocking profiling
The profiler collects goroutine blocking information similar to Google Perf Tools.
You may see an example of the profile (converted to svg) attached to
http://code.google.com/p/go/issues/detail?id=3946
The public API changes are:
+pkg runtime, func BlockProfile([]BlockProfileRecord) (int, bool)
+pkg runtime, func SetBlockProfileRate(int)
+pkg runtime, method (*BlockProfileRecord) Stack() []uintptr
+pkg runtime, type BlockProfileRecord struct
+pkg runtime, type BlockProfileRecord struct, Count int64
+pkg runtime, type BlockProfileRecord struct, Cycles int64
+pkg runtime, type BlockProfileRecord struct, embedded StackRecord

R=rsc, dave, minux.ma, r
CC=gobot, golang-dev, r, remyoudompheng
http://codereview.appspot.com/6443115
runtime: fix a panic when growing zero-width-element slices.

Fixes issue 4197.

R=golang-dev, r
CC=golang-dev
http://codereview.appspot.com/6611056
cmd/5g: avoid temporary during constant asop

func add() int {
        var a int
        a += 10
        a += 20
        a += 30
        a -= 10
        a -= 20
        a -= 30
        return a
}

before

--- prog list "add" ---
0000 (/home/dfc/src/add.go:5) TEXT      add+0(SB),$0-4
0001 (/home/dfc/src/add.go:6) MOVW      $0,R2
0002 (/home/dfc/src/add.go:7) MOVW      $10,R0
0003 (/home/dfc/src/add.go:7) ADD       R0,R2,R1
0004 (/home/dfc/src/add.go:8) MOVW      $20,R0
0005 (/home/dfc/src/add.go:8) ADD       R0,R1
0006 (/home/dfc/src/add.go:9) MOVW      $30,R0
0007 (/home/dfc/src/add.go:9) ADD       R0,R1
0008 (/home/dfc/src/add.go:10) MOVW     $10,R0
0009 (/home/dfc/src/add.go:10) SUB      R0,R1
0010 (/home/dfc/src/add.go:11) MOVW     $20,R0
0011 (/home/dfc/src/add.go:11) SUB      R0,R1
0012 (/home/dfc/src/add.go:12) MOVW     $30,R0
0013 (/home/dfc/src/add.go:12) SUB      R0,R1,R2
0014 (/home/dfc/src/add.go:12) MOVW     R2,R0
0015 (/home/dfc/src/add.go:13) MOVW     R2,R1
0016 (/home/dfc/src/add.go:13) MOVW     R2,.noname+0(FP)
0017 (/home/dfc/src/add.go:13) RET      ,

after

--- prog list "add" ---
0000 (/home/dfc/src/add.go:5) TEXT      add+0(SB),$0-4
0001 (/home/dfc/src/add.go:6) MOVW      $0,R0
0002 (/home/dfc/src/add.go:7) ADD       $10,R0
0003 (/home/dfc/src/add.go:8) ADD       $20,R0
0004 (/home/dfc/src/add.go:9) ADD       $30,R0
0005 (/home/dfc/src/add.go:10) SUB      $10,R0
0006 (/home/dfc/src/add.go:11) SUB      $20,R0
0007 (/home/dfc/src/add.go:12) SUB      $30,R0,R2
0008 (/home/dfc/src/add.go:13) MOVW     R2,R0
0009 (/home/dfc/src/add.go:13) MOVW     R2,.noname+0(FP)
0010 (/home/dfc/src/add.go:13) RET      ,

R=rsc, minux.ma, remyoudompheng
CC=golang-dev
http://codereview.appspot.com/6584056