From f57f484053f276c6fb57047cf02fa043974d7b95 Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Mon, 11 Jan 2021 14:30:16 -0800 Subject: [PATCH] [dev.regabi] cmd/compile: decouple escape analysis from Name.Vargen Escape analysis needs to know the index of result parameters for recording escape-flow information. It currently relies on Vargen for this, but it can easily figure this out for itself. So just do that instead, so that we can remove Vargen. Passes toolstash -cmp. For #43633. Change-Id: I65dedc2d73bc25e85ff400f308e50b73dc503630 Reviewed-on: https://go-review.googlesource.com/c/go/+/283192 Trust: Matthew Dempsky Trust: Dan Scales Run-TryBot: Matthew Dempsky TryBot-Result: Go Bot Reviewed-by: Dan Scales --- src/cmd/compile/internal/escape/escape.go | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go index c63383af43a..bee3878f100 100644 --- a/src/cmd/compile/internal/escape/escape.go +++ b/src/cmd/compile/internal/escape/escape.go @@ -126,6 +126,11 @@ type location struct { edges []edge // incoming edges loopDepth int // loopDepth at declaration + // resultIndex records the tuple index (starting at 1) for + // PPARAMOUT variables within their function's result type. + // For non-PPARAMOUT variables it's 0. + resultIndex int + // derefs and walkgen are used during walkOne to track the // minimal dereferences from the walk root. derefs int // >= -1 @@ -259,11 +264,16 @@ func (b *batch) initFunc(fn *ir.Func) { } // Allocate locations for local variables. - for _, dcl := range fn.Dcl { - if dcl.Op() == ir.ONAME { - e.newLoc(dcl, false) + for _, n := range fn.Dcl { + if n.Op() == ir.ONAME { + e.newLoc(n, false) } } + + // Initialize resultIndex for result parameters. + for i, f := range fn.Type().Results().FieldSlice() { + e.oldLoc(f.Nname.(*ir.Name)).resultIndex = 1 + i + } } func (b *batch) walkFunc(fn *ir.Func) { @@ -1609,8 +1619,7 @@ func (l *location) leakTo(sink *location, derefs int) { // If sink is a result parameter and we can fit return bits // into the escape analysis tag, then record a return leak. if sink.isName(ir.PPARAMOUT) && sink.curfn == l.curfn { - // TODO(mdempsky): Eliminate dependency on Vargen here. - ri := int(sink.n.Name().Vargen) - 1 + ri := sink.resultIndex - 1 if ri < numEscResults { // Leak to result parameter. l.paramEsc.AddResult(ri, derefs)