diff options
Diffstat (limited to 'src/cmd/compile/internal/gc/pgen.go')
| -rw-r--r-- | src/cmd/compile/internal/gc/pgen.go | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go index 643ba79d63..dde28f670b 100644 --- a/src/cmd/compile/internal/gc/pgen.go +++ b/src/cmd/compile/internal/gc/pgen.go @@ -120,7 +120,30 @@ func Gvarlive(n *Node) { } func removevardef(firstp *obj.Prog) { + // At VARKILLs, zero variable if it is ambiguously live. + // After the VARKILL anything this variable references + // might be collected. If it were to become live again later, + // the GC will see references to already-collected objects. + // See issue 20029. for p := firstp; p != nil; p = p.Link { + if p.As != obj.AVARKILL { + continue + } + n := p.To.Node.(*Node) + if !n.Name.Needzero { + continue + } + if n.Class != PAUTO { + Fatalf("zero of variable which isn't PAUTO %v", n) + } + if n.Type.Size()%int64(Widthptr) != 0 { + Fatalf("zero of variable not a multiple of ptr size %v", n) + } + Thearch.ZeroAuto(n, p) + } + + for p := firstp; p != nil; p = p.Link { + for p.Link != nil && (p.Link.As == obj.AVARDEF || p.Link.As == obj.AVARKILL || p.Link.As == obj.AVARLIVE) { p.Link = p.Link.Link } |