From b22af9b407dc29d1a733976484904ad0ab168466 Mon Sep 17 00:00:00 2001 From: Cherry Zhang Date: Thu, 10 Sep 2020 22:41:29 -0400 Subject: cmd/link: record only the first occurance in Reachparent graph In the deadcode pass, a type symbol may be marked twice, one without UsedInIface, one with. For the second time, don't update the Reachparent graph, so it only records the path of the first time the symbol is reached. This ensures the Reachparent graph is acyclic. TODO: add a test. (This only affects GOEXPERIMENT=fieldtrack) Change-Id: I68e8a1a69c3830bc8aee5df946151dc22dcb2b29 Reviewed-on: https://go-review.googlesource.com/c/go/+/254297 Run-TryBot: Cherry Zhang TryBot-Result: Gobot Gobot Reviewed-by: Than McIntosh --- src/cmd/link/internal/ld/deadcode.go | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/cmd/link/internal/ld/deadcode.go b/src/cmd/link/internal/ld/deadcode.go index 0269429723..35545f950e 100644 --- a/src/cmd/link/internal/ld/deadcode.go +++ b/src/cmd/link/internal/ld/deadcode.go @@ -209,7 +209,7 @@ func (d *deadcodePass) mark(symIdx, parent loader.Sym) { if symIdx != 0 && !d.ldr.AttrReachable(symIdx) { d.wq.push(symIdx) d.ldr.SetAttrReachable(symIdx, true) - if objabi.Fieldtrack_enabled != 0 { + if objabi.Fieldtrack_enabled != 0 && d.ldr.Reachparent[symIdx] == 0 { d.ldr.Reachparent[symIdx] = parent } if *flagDumpDep { -- cgit v1.2.3-54-g00ecf