allocating registers in shift and div.

fix behavior when res == a reserved register.

R=ken
OCL=32765
CL=32767

and delete some dead code.
no actual changes here.

R=ken
OCL=32764
CL=32764

R=ken
OCL=32760
CL=32760

couple of fixes to timing.sh

R=rsc
DELTA=10  (5 added, 0 deleted, 5 changed)
OCL=32742
CL=32756

R=ken
OCL=32750
CL=32753

R=gri,rsc
OCL=32748
CL=32748

timing.sh improvements

R=rsc
DELTA=334  (319 added, 0 deleted, 15 changed)
OCL=32734
CL=32736

R=r
DELTA=0  (0 added, 0 deleted, 0 changed)
OCL=32730
CL=32735

add script to automate timing

R=rsc
DELTA=78  (68 added, 0 deleted, 10 changed)
OCL=32729
CL=32732

R=rsc
DELTA=682  (511 added, 171 deleted, 0 changed)
OCL=32725
CL=32727

split into typecheck + walk

R=ken
OCL=32726
CL=32726

R=ken
OCL=32716
CL=32720

start a log of progress

R=rsc
DELTA=222  (185 added, 17 deleted, 20 changed)
OCL=32701
CL=32718

R=rsc
DELTA=311  (311 added, 0 deleted, 0 changed)
OCL=32696
CL=32699

R=rsc
DELTA=40  (0 added, 0 deleted, 40 changed)
OCL=32694
CL=32698

R=rsc
DELTA=41  (41 added, 0 deleted, 0 changed)
OCL=32692
CL=32697

R=rsc
DELTA=28  (0 added, 20 deleted, 8 changed)
OCL=32676
CL=32684

R=rsc
DELTA=45  (28 added, 4 deleted, 13 changed)
OCL=32673
CL=32675

R=rsc
DELTA=19  (18 added, 0 deleted, 1 changed)
OCL=32656
CL=32670

typecheck.c is now responsible for all type checking
except for assignment and function argument "..."

R=ken
OCL=32661
CL=32667

- emit line tag id's in html mode
- support for general html tags
- better names for a few identifiers

godoc.go:
- emit links from exported names to source code
  (actual placement needs fine-tuning)

R=rsc
DELTA=108  (68 added, 4 deleted, 36 changed)
OCL=32639
CL=32654

- replace forward-declared types with complete
  declaration when it is found

R=rsc
DELTA=23  (15 added, 0 deleted, 8 changed)
OCL=32618
CL=32618

DELTA=5  (5 added, 0 deleted, 0 changed)
OCL=32484
CL=32617

- prepare for generation of HTML id tags and links
- do HTML-escaping in central print routine
- move tabwriter setup into printer
- fixed various TODOs

godoc:
- removed tabwriter setup, need for various HTML-escaping

R=rsc
DELTA=210  (107 added, 36 deleted, 67 changed)
OCL=32612
CL=32616

R=rsc
DELTA=100  (82 added, 4 deleted, 14 changed)
OCL=32609
CL=32615

types were supposed to be identical but only needed to be
compatible.  This gets rid of the Type.literal method.  I
renamed the Type.rep method to Type.lit because I believe it
corresponds to the term "literal" as used in the spec.

R=rsc
APPROVED=rsc
DELTA=228  (57 added, 35 deleted, 136 changed)
OCL=32606
CL=32608

the position where they were defined so I can produce good
error messages on redefinitions.

R=rsc
APPROVED=rsc
DELTA=204  (126 added, 13 deleted, 65 changed)
OCL=32599
CL=32605

R=rsc
DELTA=23  (23 added, 0 deleted, 0 changed)
OCL=32592
CL=32595

add commentary about findVar's invariant.

R=rsc
DELTA=6  (3 added, 0 deleted, 3 changed)
OCL=32583
CL=32594

R=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=32591
CL=32593

R=rsc
DELTA=73  (27 added, 25 deleted, 21 changed)
OCL=32587
CL=32587

R=ken
OCL=32581
CL=32581

R=ken
OCL=32576
CL=32580

- make token.Position.String more robust

TBR=rsc
DELTA=20  (10 added, 6 deleted, 4 changed)
OCL=32564
CL=32564

R=rsc
OCL=32563
CL=32563

handled by typecheck.

second switch is gone

move floating point minus into back end

R=ken
OCL=32558
CL=32558

R=rsc
DELTA=28  (19 added, 0 deleted, 9 changed)
OCL=32550
CL=32554

- more orthogonal functionality of filter functions for better re-use

go/doc/doc.go:
- simplified interface
- collect filenames of packages so that they can be shown

godoc:
- removed TODO, show list of package (linked) files used to create documentation

R=rsc
DELTA=130  (68 added, 24 deleted, 38 changed)
OCL=32549
CL=32552

R=gri
APPROVED=gri
DELTA=33  (20 added, 6 deleted, 7 changed)
OCL=32544
CL=32546

R=rsc
DELTA=2  (0 added, 0 deleted, 2 changed)
OCL=32540
CL=32545