llgo/ssa getDefer fix: move to function start

ssa/stmt_builder.go

@@ -191,11 +191,12 @@ func (b Builder) deferKey() Expr {
 func (b Builder) getDefer() *aDefer {
 	self := b.Func
 	if self.defer_ == nil {
-		// TODO(xsw): move to funtion start
+		// TODO(xsw): if in pkg.init?
 		// 0: proc func(uintptr)
 		// 1: bits uintptr
 		// 2: link *Defer
 		// 3: rund int
+		b.SetBlockEx(b.blk, AtStart, false)
 		prog := b.Prog
 		key := b.deferKey()
 		deferfn := prog.Null(prog.VoidPtr())
@@ -204,6 +205,7 @@ func (b Builder) getDefer() *aDefer {
 		ptr := b.aggregateAlloca(prog.Defer(), deferfn.impl, zero.impl, link.impl)
 		deferData := Expr{ptr, prog.DeferPtr()}
 		b.pthreadSetspecific(key, deferData)
+		b.SetBlockEx(b.blk, AtEnd, false)
 		self.defer_ = &aDefer{
 			key:     key,
 			data:    deferData,