cmd/compile: fix some plive comments

The liveness analysis no longer directly emits PCDATA. Fix stale
comments that say so.

Change-Id: Id26b112ddf4c13a12ebf766f64bf57c68fbfe3ef
Reviewed-on: https://go-review.googlesource.com/67691
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/gc/plive.go b/src/cmd/compile/internal/gc/plive.go
index 9d2dcf658f9a7d573f19ba56e8544d3c70fc573c..49d0229702b1d4170ba8fbcf69547af6f4d9185b 100644 (file)
--- a/src/cmd/compile/internal/gc/plive.go
+++ b/src/cmd/compile/internal/gc/plive.go
@@ -692,7 +692,7 @@ func (lv *Liveness) epilogue() {
        for _, b := range lv.f.Blocks {
                be := lv.blockEffects(b)
 
-               // walk backward, emit pcdata and populate the maps
+               // walk backward, construct maps at each safe point
                index := int32(be.lastbitmapindex)
                if index < 0 {
                        // the first block we encounter should have the ATEXT so
@@ -1012,7 +1012,8 @@ Outer:
        }
        lv.livevars = lv.livevars[:uniq]
 
-       // Rewrite PCDATA instructions to use new numbering.
+       // Record compacted stack map indexes for each value.
+       // These will later become PCDATA instructions.
        lv.showlive(nil, lv.livevars[0])
        pos := 1
        lv.stackMapIndex = make(map[*ssa.Value]int)