cmd/compile: add sliceBound

Add a constant for the magic -1 for slice bounds.
Use it.
Enforce more aggressively that bounds must be
slice, ddd, or non-negative.
Remove ad hoc check in plive.go.
Check bounds before constructing an array type
when typechecking.

All changes are manual.

Passes toolstash -cmp.

Change-Id: I9fd9cc789d7d4b4eea3b30b24037a254d3788add
Reviewed-on: https://go-review.googlesource.com/21348
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Josh Bleecher Snyder 2016-03-31 09:29:39 -07:00
parent 4b95575bd4
commit e775b8df7a
5 changed files with 26 additions and 16 deletions

View file

@ -249,7 +249,7 @@ func dowidth(t *Type) {
w = t.Bound * t.Elem().Width
t.Align = t.Elem().Align
} else if t.Bound == -1 {
} else if t.IsSlice() {
w = int64(sizeof_Array)
checkwidth(t.Elem())
t.Align = uint8(Widthptr)