cmd/compile: fix the missing size for FuncInfoSym

Change-Id: I46543e188bf25384e529a9d5a3095033ac618bbd
Reviewed-on: https://go-review.googlesource.com/c/go/+/402057
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>

Author: zhouguangyuan0718

src/cmd/internal/obj/objfile.go

@@ -726,11 +726,13 @@ func genFuncInfoSyms(ctxt *Link) {
 		}
 
 		o.Write(&b)
+		p := b.Bytes()
 		isym := &LSym{
 			Type:   objabi.SDATA, // for now, I don't think it matters
 			PkgIdx: goobj.PkgIdxSelf,
 			SymIdx: symidx,
-			P:      append([]byte(nil), b.Bytes()...),
+			P:      append([]byte(nil), p...),
+			Size:   int64(len(p)),
 		}
 		isym.Set(AttrIndexed, true)
 		symidx++