From 1ec056244e1a058ea3a21f0abd1165d710398416 Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Mon, 24 May 2021 04:41:58 -0700 Subject: [PATCH] [dev.typeparams] cmd/compile: inlining tweaks for toolstash This CL makes to minor changes motivated by making it easier to make large-scale changes to the inliner while satisfying toolstash -cmp: 1. When creating inlining variables, make sure to preserve the AutoTemp flag. This is necessary so that temporary variables introduced by rewriting f(g()) calls during typecheck stay autotemp after inlining and are (correctly) omitted from DWARF debugging information. 2. When sorting variables for stack frame layout, use a stable sort. This ensures that layout is insensitive to whether deadcode elimination happens before or after inlining. Change-Id: I672e752a873c7e16749b9873fd6573607e074309 Reviewed-on: https://go-review.googlesource.com/c/go/+/323011 Trust: Matthew Dempsky Trust: Dan Scales Run-TryBot: Matthew Dempsky TryBot-Result: Go Bot Reviewed-by: Dan Scales --- src/cmd/compile/internal/inline/inl.go | 1 + src/cmd/compile/internal/ssagen/pgen.go | 5 ++++- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/inline/inl.go b/src/cmd/compile/internal/inline/inl.go index 00f8447f05..042e3f2332 100644 --- a/src/cmd/compile/internal/inline/inl.go +++ b/src/cmd/compile/internal/inline/inl.go @@ -1029,6 +1029,7 @@ func inlvar(var_ *ir.Name) *ir.Name { n.SetType(var_.Type()) n.Class = ir.PAUTO n.SetUsed(true) + n.SetAutoTemp(var_.AutoTemp()) n.Curfn = ir.CurFunc // the calling function, not the called one n.SetAddrtaken(var_.Addrtaken()) diff --git a/src/cmd/compile/internal/ssagen/pgen.go b/src/cmd/compile/internal/ssagen/pgen.go index 62567535d7..93157bfa11 100644 --- a/src/cmd/compile/internal/ssagen/pgen.go +++ b/src/cmd/compile/internal/ssagen/pgen.go @@ -114,7 +114,10 @@ func (s *ssafn) AllocFrame(f *ssa.Func) { } } - sort.Sort(byStackVar(fn.Dcl)) + // Use sort.Stable instead of sort.Sort so stack layout (and thus + // compiler output) is less sensitive to frontend changes that + // introduce or remove unused variables. + sort.Stable(byStackVar(fn.Dcl)) // Reassign stack offsets of the locals that are used. lastHasPtr := false