run.bash: add sanity test for race detector

R=golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/6612064
cmd/gc: fix incomplete export data when inlining with local variables.

When local declarations needed unexported types, these could
be missing in the export data.

Fixes build with -gcflags -lll, except for exp/gotype.

R=golang-dev, rsc, lvd
CC=golang-dev
http://codereview.appspot.com/6813067
cmd/gc: racewalk: fix instrumentation of ninit lists
The idea is to (1) process ninit of all nodes,
and (2) put instrumentation of ninit into the nodes themselves (not the top-level statement ninit).
Fixes issue 4304.

R=golang-dev, rsc
CC=golang-dev, lvd
http://codereview.appspot.com/6818049
go/build: support compiler as build constraint

This supports writing different .c/.s code when using gccgo.

R=golang-dev, dsymonds, iant, rsc
CC=golang-dev
http://codereview.appspot.com/6823055
cmd/go: fixes to gccgo support

* Use -fgo-pkgpath and -gccgopkgpath rather than -fgo-prefix
  and -gccgoprefix.
* Define GOPKGPATH when compiling .c or .s files for gccgo.
* Use -fgo-relative-import-path.
* Produce .o files for gccgo, not .[568] files.
* Pass -E when linking if using cgo.

R=golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/6820064
cmd/cgo: improve gccgo support

Use wrapper functions to tell scheduler what we are doing.

With this patch, and a separate patch to the go tool, all the
cgo tests pass with gccgo.

R=golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/6812058
exp/types/staging: filling in more blanks

- simplified assignment checking by removing duplicate code
- implemented field lookup (methods, structs, embedded fields)
- importing methods (not just parsing them)
- type-checking functions and methods
- typechecking more statements (inc/dec, select, return)
- tracing support for easier debugging
- handling nil more correctly (comparisons)
- initial support for [...]T{} arrays
- initial support for method expressions
- lots of bug fixes

All packages under pkg/go as well as pkg/exp/types typecheck
now with pkg/exp/gotype applied to them; i.e., a significant
amount of typechecking works now (several statements are not
implemented yet, but handling statements is almost trivial in
comparison with typechecking expressions).

R=rsc
CC=golang-dev
http://codereview.appspot.com/6768063
cmd/gc, runtime: pass PC directly to racefuncenter.

go test -race -run none -bench . encoding/json
benchmark                      old ns/op    new ns/op    delta
BenchmarkCodeEncoder          3207689000   1716149000  -46.50%
BenchmarkCodeMarshal          3206761000   1715677000  -46.50%
BenchmarkCodeDecoder          8647304000   4482709000  -48.16%
BenchmarkCodeUnmarshal        8032217000   3451248000  -57.03%
BenchmarkCodeUnmarshalReuse   8016722000   3480502000  -56.58%
BenchmarkSkipValue           10340453000   4560313000  -55.90%

benchmark                       old MB/s     new MB/s  speedup
BenchmarkCodeEncoder                0.60         1.13    1.88x
BenchmarkCodeMarshal                0.61         1.13    1.85x
BenchmarkCodeDecoder                0.22         0.43    1.95x
BenchmarkCodeUnmarshal              0.24         0.56    2.33x
BenchmarkCodeUnmarshalReuse         0.24         0.56    2.33x
BenchmarkSkipValue                  0.19         0.44    2.32x

Fixes issue 4248.

R=dvyukov, golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/6815066
syscall: add {Get,Set,List,Remove}xattr on Linux.

R=golang-dev, minux.ma, fullung, dave, rsc, hanwenn
CC=golang-dev
http://codereview.appspot.com/6350074

Committer: Russ Cox <rsc@golang.org>
cmd/gc: racewalk: fix a bunch of minor issues
1. Prepend racefuncenter() to fn->enter -- fn->enter can contain new() calls,
and we want them to be in the scope of the function.
2. Dump fn->enter and fn->exit.
3. Add TODO that OTYPESW expression can contain interesting memory accesses.
4. Ignore only _ names instead of all names starting with _.

R=golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/6822048
cmd/gc: fix build

R=golang-dev
CC=golang-dev
http://codereview.appspot.com/6826047