From bbee5236cd64a11a2bfd194eb9f809f51cae0870 Mon Sep 17 00:00:00 2001 From: Michael Munday Date: Mon, 10 Aug 2020 08:01:21 -0700 Subject: [release-branch.go1.15] cmd/internal/obj: fix inline marker issue on s390x The optimization that replaces inline markers with pre-existing instructions assumes that 'Prog' values produced by the compiler are still reachable after the assembler has run. This was not true on s390x where the assembler was removing NOP instructions from the linked list of 'Prog' values. This led to broken inlining data which in turn caused an infinite loop in the runtime traceback code. Fix this by stopping the s390x assembler backend removing NOP values. It does not make any difference to the output of the assembler because NOP instructions are 0 bytes long anyway. Note: compiler check omitted from backport to reduce risk of change. Fixes #40693. Change-Id: I4eb570de13165cde342d5fb2ee3218945ddf4b52 Reviewed-on: https://go-review.googlesource.com/c/go/+/248478 Run-TryBot: Michael Munday TryBot-Result: Gobot Gobot Reviewed-by: Dmitri Shuralyov Reviewed-by: Keith Randall --- src/cmd/internal/obj/s390x/objz.go | 11 ----------- 1 file changed, 11 deletions(-) diff --git a/src/cmd/internal/obj/s390x/objz.go b/src/cmd/internal/obj/s390x/objz.go index b14dc810fa..ef6335d849 100644 --- a/src/cmd/internal/obj/s390x/objz.go +++ b/src/cmd/internal/obj/s390x/objz.go @@ -283,17 +283,6 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) { ACMPUBNE: q = p p.Mark |= BRANCH - if p.Pcond != nil { - q := p.Pcond - for q.As == obj.ANOP { - q = q.Link - p.Pcond = q - } - } - - case obj.ANOP: - q.Link = p.Link /* q is non-nop */ - p.Link.Mark |= p.Mark default: q = p -- cgit v1.2.3-54-g00ecf