code review 9033043: cmd/gc: fix some overflows in the compiler

cmd/gc: fix some overflows in the compiler
Some 64-bit fields were run through 32-bit words, some counts were
not checked for overflow, and relocations must fit in 32 bits.
Tests to follow.

[r, 2013-04-30 02:48:54]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[dsymonds, 2013-04-30 05:42:06]

LGTM

[r, 2013-04-30 05:44:43]

*** Submitted as https://code.google.com/p/go/source/detail?r=587ffbeec2f5 ***

cmd/gc: fix some overflows in the compiler
Some 64-bit fields were run through 32-bit words, some counts were
not checked for overflow, and relocations must fit in 32 bits.
Tests to follow.

R=golang-dev, dsymonds
CC=golang-dev
https://codereview.appspot.com/9033043

[dave_cheney.net, 2013-04-30 05:51:28]

Some general questions about the use of int64 vs vlong.

https://codereview.appspot.com/9033043/diff/1/src/cmd/6g/cgen.c
File src/cmd/6g/cgen.c (right):

https://codereview.appspot.com/9033043/diff/1/src/cmd/6g/cgen.c#newcode571
src/cmd/6g/cgen.c:571: uint64 w;
uint64 w, v;

https://codereview.appspot.com/9033043/diff/1/src/cmd/6g/gobj.c
File src/cmd/6g/gobj.c (right):

https://codereview.appspot.com/9033043/diff/1/src/cmd/6g/gobj.c#newcode505
src/cmd/6g/gobj.c:505: int64 o;
should this be uint64 or vlong ?

https://codereview.appspot.com/9033043/diff/1/src/cmd/6g/gsubr.c
File src/cmd/6g/gsubr.c (right):

https://codereview.appspot.com/9033043/diff/1/src/cmd/6g/gsubr.c#newcode1954
src/cmd/6g/gsubr.c:1954: int64 v, w;
should w be vlong ?

[r, 2013-04-30 06:32:48]

The compiler is sloppy about it and should be tidied up, but not now.
int64 and vlong are the same thing.

-rob