s.output.Data() was being retrieved before the synchronization
point, which meant that it could be retrieved before the
goroutine wrote it.  Using gccgo this caused random errors.

R=gri
DELTA=2  (1 added, 0 deleted, 1 changed)
OCL=31046
CL=31267

and make 5c, 8c use them.

centralizes reachability analysis
and switch generation.

now 8c doesn't have spurious warnings
in pkg/runtime.

R=ken
OCL=31266
CL=31266

  Natural, Integer, and Rational numbers
- added Value() methods to access small Natural and Integers
  as uint64 or int64 respectively, and to get the components
  of Rational numbers
- fixed a bug with Integer creation
- removed some _'s from names
- added more comments in places
- added test cases

R=rsc
DELTA=184  (127 added, 11 deleted, 46 changed)
OCL=31210
CL=31265

needed for heap allocation if variable escapes.

package main
func main(){
	var i interface{} = 42;
	switch v := i.(type) {
	case int:
		println(&v, v);
	}
}

R=ken
OCL=31245
CL=31245

	x << "a"
	1 << int(2)

R=ken
OCL=31244
CL=31244

R=rsc
APPROVED=rsc
DELTA=46  (0 added, 5 deleted, 41 changed)
OCL=31241
CL=31243

R=rsc
APPROVED=rsc
DELTA=32  (26 added, 4 deleted, 2 changed)
OCL=31172
CL=31242

* give genwrapper and genembedtramp the same signature.
* move duint8, duint16, duint32, duint64, duintptr into gc.
* tidy genwrapper.
* bug involving struct field symbols in signature list.
  (hash-order dependent so hard to trigger)
* new Type print format %#-T like %#T but omits
  names on function arguments.

R=ken
OCL=31237
CL=31237

missing break after error.

dot symbol bug fix: leave sym alone
(was incorrect for inserted cross-package dots).

R=ken
OCL=31234
CL=31236

for now, canSet stays.
i will look into getting rid of it in
a future CL.

R=r
DELTA=420  (419 added, 0 deleted, 1 changed)
OCL=31231
CL=31235

R=ken
OCL=31233
CL=31233

interface = (*int)(nil) is not the same as
interface = nil.

package main
func main() {
	var x interface{} = (*int)(nil);
	println(x.(*int));
}

R=ken
OCL=31232
CL=31232

R=ken
OCL=31230
CL=31230

when implicit assignment would have been okay.

R=ken
OCL=31225
CL=31227

package main

func main() {
       var x interface {} = 42;
       switch x := x.(type) {
       case int:
       case foo:
       }
}

before:
x.go:7: non-type case in type switch
x.go:7: inappropriate case for a type switch

now:
x.go:7: foo: undefined

R=ken
OCL=31221
CL=31221

R=r
DELTA=179  (172 added, 6 deleted, 1 changed)
OCL=31215
CL=31220

package main
func main() {
       var x interface{};
       switch x {
       case 41:
       case "b":
       }
}

before:
x.go:5: fatal error: exprcmp

now:
x.go:5: illegal types for operand: EQ
	interface { }
	int
x.go:6: illegal types for operand: EQ
	interface { }
	string

R=ken
OCL=31217
CL=31219

  * use structs instead of interfaces
  * compiler lays out data structures ahead of time,
    so no more parsing of strings.
  * unified reflect data structures with interface
    runtime data structures.
  * richer data structures should enable reflection
    on chans and maps, but not implemented here.

R=r,iant
DELTA=1179  (1179 added, 0 deleted, 0 changed)
OCL=31107
CL=31213

R=rsc
DELTA=248  (40 added, 108 deleted, 100 changed)
OCL=31211
CL=31211

- display: show '...' if a struct/interface has fields/methods removed; show
  struct/interface w/o {}'s if all fields/methods were removed; and show the
  {}'s if the struct/interface was empty to begin with

R=rsc
DELTA=41  (36 added, 0 deleted, 5 changed)
OCL=31201
CL=31204

R=rsc
DELTA=4  (4 added, 0 deleted, 0 changed)
OCL=31192
CL=31198

- use FilterExports instead of the various predicates in printer.go and doc.go
  which simplifies a lot of code and makes it easier to deal with complex cases

R=rsc
DELTA=445  (197 added, 190 deleted, 58 changed)
OCL=31110
CL=31196

R=rsc
APPROVED=rsc
DELTA=7  (0 added, 1 deleted, 6 changed)
OCL=31189
CL=31191

R=ken
OCL=31190
CL=31190

8bit and 16bit, some optoas, replaced Addr.index with
Addr.name

empty function compiles, mutex compiles

R=rsc
APPROVED=rsc
DELTA=908  (83 added, 41 deleted, 784 changed)
OCL=31127
CL=31188

R=rsc
APPROVED=rsc
DELTA=48  (30 added, 16 deleted, 2 changed)
OCL=31152
CL=31187

R=rsc
APPROVED=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=31151
CL=31168

R=r
OCL=31156
CL=31156

R=ken
OCL=31149
CL=31149

R=r,iant
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=31146
CL=31148

R=rsc
DELTA=77  (76 added, 0 deleted, 1 changed)
OCL=31147
CL=31147

fix tests of bad map keys to use slices instead.

R=r
DELTA=7  (0 added, 1 deleted, 6 changed)
OCL=31123
CL=31145

alignment issue is fixed.

R=ken
OCL=31124
CL=31144

R=rsc
APPROVED=rsc
DELTA=28  (28 added, 0 deleted, 0 changed)
OCL=31128
CL=31130

R=rsc
APPROVED=rsc
DELTA=4  (0 added, 0 deleted, 4 changed)
OCL=31016
CL=31126

R=ken
OCL=31125
CL=31125

R=rsc
DELTA=59  (44 added, 13 deleted, 2 changed)
OCL=31105
CL=31105

R=rsc
DELTA=57  (34 added, 10 deleted, 13 changed)
OCL=31098
CL=31101

R=r
DELTA=113  (89 added, 9 deleted, 15 changed)
OCL=31087
CL=31096

(actually slices encode but do not decode yet)

R=rsc
DELTA=221  (82 added, 65 deleted, 74 changed)
OCL=31095
CL=31095