From 40ba119e3f990fd570ec928307e92a5b6a76bd0e Mon Sep 17 00:00:00 2001 From: Dan Scales Date: Mon, 9 Aug 2021 16:00:29 -0700 Subject: [dev.typeparams] cmd/compile: keep export format unchanged if no type params are exported Added new export tags 'G' and 'U' to export parameterized functions/methods and parameterized types respectively. This has the advantage that the Go 1.18 format remains backward-compatible with the Go 1.17 format if no type parameters are exported. Change-Id: I9dba8faaa65609eb3f9c693bd0c79daee98bd865 Reviewed-on: https://go-review.googlesource.com/c/go/+/340989 Trust: Dan Scales Run-TryBot: Dan Scales TryBot-Result: Go Bot Reviewed-by: Robert Griesemer Reviewed-by: Robert Findley Reviewed-by: Matthew Dempsky --- src/cmd/compile/internal/typecheck/iexport.go | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) (limited to 'src/cmd/compile/internal/typecheck/iexport.go') diff --git a/src/cmd/compile/internal/typecheck/iexport.go b/src/cmd/compile/internal/typecheck/iexport.go index 2944908bcb..5f510a0a25 100644 --- a/src/cmd/compile/internal/typecheck/iexport.go +++ b/src/cmd/compile/internal/typecheck/iexport.go @@ -314,12 +314,7 @@ func WriteExports(out io.Writer, extensions bool) { // Assemble header. var hdr intWriter hdr.WriteByte('i') - if base.Flag.G > 0 { - hdr.uint64(iexportVersionCurrent) - } else { - // Use old export format if doing -G=0 (no generics) - hdr.uint64(iexportVersionPosCol) - } + hdr.uint64(iexportVersionCurrent) hdr.uint64(uint64(p.strings.Len())) hdr.uint64(dataLen) @@ -487,7 +482,11 @@ func (p *iexporter) doDecl(n *ir.Name) { } // Function. - w.tag('F') + if n.Type().TParams().NumFields() == 0 { + w.tag('F') + } else { + w.tag('G') + } w.pos(n.Pos()) // The tparam list of the function type is the // declaration of the type params. So, write out the type @@ -495,7 +494,7 @@ func (p *iexporter) doDecl(n *ir.Name) { // referenced via their type offset (via typOff) in all // other places in the signature and function that they // are used. - if base.Flag.G > 0 { + if n.Type().TParams().NumFields() > 0 { w.tparamList(n.Type().TParams().FieldSlice()) } w.signature(n.Type()) @@ -544,10 +543,14 @@ func (p *iexporter) doDecl(n *ir.Name) { } // Defined type. - w.tag('T') + if len(n.Type().RParams()) == 0 { + w.tag('T') + } else { + w.tag('U') + } w.pos(n.Pos()) - if base.Flag.G > 0 { + if len(n.Type().RParams()) > 0 { // Export type parameters, if any, needed for this type w.typeList(n.Type().RParams()) } -- cgit v1.2.3-54-g00ecf