From 95748d1b741d2c612cf90d9b6f4f8bdb81800e23 Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Tue, 18 May 2021 01:20:13 -0700 Subject: [PATCH] [dev.typeparams] cmd/compile: avoid some redundant type construction This CL updates noder and typecheck to avoid a couple of instances of redundant evaluation of type expressions: 1. When noding struct fields or parameter tuples, check for syntax.Type reuse between adjacent fields and then reuse the corresponding ir.Node type expression. It would perhaps be even better to avoid re-noding the type expression too, but noder's days are numbered anyway, so I'd rather be minimally invasive here. 2. When importing an empty interface, reuse the same cached empty interface instance that is used for empty interfaces that appear in source. This matches types2's behavior, which uses a single types2.Interface instance for all empty interfaces. These changes are motivated by making it possible to migrate from typecheck to types2 while passing toolstash -cmp. Updates #46208. Change-Id: Ia6458894494464d863181db356f3284630c90ffe Reviewed-on: https://go-review.googlesource.com/c/go/+/320789 Run-TryBot: Matthew Dempsky Trust: Matthew Dempsky TryBot-Result: Go Bot Reviewed-by: Robert Griesemer --- src/cmd/compile/internal/noder/noder.go | 6 ++++++ src/cmd/compile/internal/typecheck/iimport.go | 4 ++++ 2 files changed, 10 insertions(+) diff --git a/src/cmd/compile/internal/noder/noder.go b/src/cmd/compile/internal/noder/noder.go index 4c7c9fc322f..06c3b00601f 100644 --- a/src/cmd/compile/internal/noder/noder.go +++ b/src/cmd/compile/internal/noder/noder.go @@ -625,6 +625,9 @@ func (p *noder) params(params []*syntax.Field, dddOk bool) []*ir.Field { for i, param := range params { p.setlineno(param) nodes = append(nodes, p.param(param, dddOk, i+1 == len(params))) + if i > 0 && params[i].Type == params[i-1].Type { + nodes[i].Ntype = nodes[i-1].Ntype + } } return nodes } @@ -917,6 +920,9 @@ func (p *noder) structType(expr *syntax.StructType) ir.Node { } else { n = ir.NewField(p.pos(field), p.name(field.Name), p.typeExpr(field.Type), nil) } + if i > 0 && expr.FieldList[i].Type == expr.FieldList[i-1].Type { + n.Ntype = l[i-1].Ntype + } if i < len(expr.TagList) && expr.TagList[i] != nil { n.Note = constant.StringVal(p.basicLit(expr.TagList[i])) } diff --git a/src/cmd/compile/internal/typecheck/iimport.go b/src/cmd/compile/internal/typecheck/iimport.go index 3fb675f8244..16b3e7ceba4 100644 --- a/src/cmd/compile/internal/typecheck/iimport.go +++ b/src/cmd/compile/internal/typecheck/iimport.go @@ -745,6 +745,10 @@ func (r *importReader) typ1() *types.Type { methods[i] = types.NewField(pos, sym, typ) } + if len(embeddeds)+len(methods) == 0 { + return types.Types[types.TINTER] + } + t := types.NewInterface(r.currPkg, append(embeddeds, methods...)) // Ensure we expand the interface in the frontend (#25055).