cmd/compile: keep variable numbering for inlineable exported functions

Another step towards hooking up exported inlined function bodies.

Change-Id: Ib8094b03ac7970fee0e51b5826b5f8aa232e23fb
Reviewed-on: https://go-review.googlesource.com/20605Reviewed-by: Alan Donovan <adonovan@google.com>
Run-TryBot: Robert Griesemer <gri@golang.org>

src/cmd/compile/internal/gc/bexport.go

@@ -276,12 +276,16 @@ func Export(out *obj.Biobuf, trace bool) int {
 	}
 	for _, sym := range funcs {
 		p.string(sym.Name)
-		// The type can only be a signature for functions. However, by always
-		// writing the complete type specification (rather than just a signature)
-		// we keep the option open of sharing common signatures across multiple
-		// functions as a means to further compress the export data.
-		p.typ(sym.Def.Type)
-		p.inlinedBody(sym.Def)
+		sig := sym.Def.Type
+		inlineable := p.isInlineable(sym.Def)
+		p.paramList(sig.Params(), inlineable)
+		p.paramList(sig.Results(), inlineable)
+		index := -1
+		if inlineable {
+			index = len(p.inlined)
+			p.inlined = append(p.inlined, sym.Def.Func)
+		}
+		p.int(index)
 		if p.trace {
 			p.tracef("\n")
 		}
@@ -476,10 +480,17 @@ func (p *exporter) typ(t *Type) {
 				p.tracef("\n")
 			}
 			p.string(m.Sym.Name)
-			p.paramList(m.Type.Recvs())
-			p.paramList(m.Type.Params())
-			p.paramList(m.Type.Results())
-			p.inlinedBody(m.Type.Nname)
+			sig := m.Type
+			inlineable := p.isInlineable(sig.Nname)
+			p.paramList(sig.Recvs(), inlineable)
+			p.paramList(sig.Params(), inlineable)
+			p.paramList(sig.Results(), inlineable)
+			index := -1
+			if inlineable {
+				index = len(p.inlined)
+				p.inlined = append(p.inlined, sig.Nname.Func)
+			}
+			p.int(index)
 		}
 
 		if p.trace && len(methods) > 0 {
@@ -516,8 +527,8 @@ func (p *exporter) typ(t *Type) {
 
 	case TFUNC:
 		p.tag(signatureTag)
-		p.paramList(t.Params())
-		p.paramList(t.Results())
+		p.paramList(t.Params(), false)
+		p.paramList(t.Results(), false)
 
 	case TINTER:
 		p.tag(interfaceTag)
@@ -596,8 +607,8 @@ func (p *exporter) method(m *Field) {
 	// TODO(gri) For functions signatures, we use p.typ() to export
 	// so we could share the same type with multiple functions. Do
 	// the same here, or never try to do this for functions.
-	p.paramList(m.Type.Params())
-	p.paramList(m.Type.Results())
+	p.paramList(m.Type.Params(), false)
+	p.paramList(m.Type.Results(), false)
 }
 
 // fieldName is like qualifiedName but it doesn't record the package
@@ -631,7 +642,7 @@ func basetypeName(t *Type) string {
 	return ""
 }
 
-func (p *exporter) paramList(params *Type) {
+func (p *exporter) paramList(params *Type, numbered bool) {
 	if params.Etype != TSTRUCT || !params.Funarg {
 		Fatalf("exporter: parameter list expected")
 	}
@@ -640,16 +651,16 @@ func (p *exporter) paramList(params *Type) {
 	// (look at the first parameter only since either all
 	// names are present or all are absent)
 	n := countfield(params)
-	if n > 0 && parName(params.Field(0)) == "" {
+	if n > 0 && parName(params.Field(0), numbered) == "" {
 		n = -n
 	}
 	p.int(n)
 	for q, it := IterFields(params); q != nil; q = it.Next() {
-		p.param(q, n)
+		p.param(q, n, numbered)
 	}
 }
 
-func (p *exporter) param(q *Field, n int) {
+func (p *exporter) param(q *Field, n int, numbered bool) {
 	t := q.Type
 	if q.Isddd {
 		// create a fake type to encode ... just for the p.typ call
@@ -659,7 +670,7 @@ func (p *exporter) param(q *Field, n int) {
 	}
 	p.typ(t)
 	if n > 0 {
-		p.string(parName(q))
+		p.string(parName(q, numbered))
 	}
 	// TODO(gri) This is compiler-specific (escape info).
 	// Move into compiler-specific section eventually?
@@ -670,7 +681,7 @@ func (p *exporter) param(q *Field, n int) {
 	p.note(q.Note)
 }
 
-func parName(q *Field) string {
+func parName(q *Field, numbered bool) string {
 	if q.Sym == nil {
 		return ""
 	}
@@ -687,9 +698,11 @@ func parName(q *Field) string {
 			Fatalf("exporter: unexpected parameter name: %s", name)
 		}
 	}
-	// undo gc-internal name specialization
-	if i := strings.Index(name, "·"); i > 0 {
-		name = name[:i] // cut off numbering
+	// undo gc-internal name specialization unless required
+	if !numbered {
+		if i := strings.Index(name, "·"); i > 0 {
+			name = name[:i] // cut off numbering
+		}
 	}
 	return name
 }
@@ -775,18 +788,16 @@ func (p *exporter) float(x *Mpflt) {
 // ----------------------------------------------------------------------------
 // Inlined function bodies
 
-func (p *exporter) inlinedBody(n *Node) {
-	index := -1 // index < 0 => not inlined
+func (p *exporter) isInlineable(n *Node) bool {
 	if n != nil && n.Func != nil && len(n.Func.Inl.Slice()) != 0 {
 		// when lazily typechecking inlined bodies, some re-exported ones may not have been typechecked yet.
 		// currently that can leave unresolved ONONAMEs in import-dot-ed packages in the wrong package
 		if Debug['l'] < 2 {
 			typecheckinl(n)
 		}
-		index = len(p.inlined) // index >= 0 => inlined
-		p.inlined = append(p.inlined, n.Func)
+		return true
 	}
-	p.int(index)
+	return false
 }
 
 func (p *exporter) nodeList(list Nodes) {

src/cmd/compile/internal/gc/bimport.go

@@ -77,16 +77,18 @@ func Import(in *bufio.Reader) {
 	for i := p.int(); i > 0; i-- {
 		// parser.go:hidden_fndcl
 		sym := p.localname()
-		typ := p.typ()
+		params := p.paramList()
+		result := p.paramList()
 		inl := p.int()
 
+		sig := functype(nil, params, result)
 		importsym(sym, ONAME)
-		if sym.Def != nil && sym.Def.Op == ONAME && !Eqtype(typ, sym.Def.Type) {
-			Fatalf("importer: inconsistent definition for func %v during import\n\t%v\n\t%v", sym, sym.Def.Type, typ)
+		if sym.Def != nil && sym.Def.Op == ONAME && !Eqtype(sig, sym.Def.Type) {
+			Fatalf("importer: inconsistent definition for func %v during import\n\t%v\n\t%v", sym, sym.Def.Type, sig)
 		}
 
 		n := newfuncname(sym)
-		n.Type = typ
+		n.Type = sig
 		declare(n, PFUNC)
 		funchdr(n)
 
@@ -94,7 +96,7 @@ func Import(in *bufio.Reader) {
 		n.Func.Inl.Set(nil)
 		if inl >= 0 {
 			if inl != len(p.inlined) {
-				panic("inlined body list inconsistent")
+				panic(fmt.Sprintf("inlined body list inconsistent: %d != %d", inl, len(p.inlined)))
 			}
 			p.inlined = append(p.inlined, n.Func)
 		}
@@ -113,7 +115,7 @@ func Import(in *bufio.Reader) {
 	// read inlined functions bodies
 	n := p.int()
 	for i := 0; i < n; i++ {
-		body := p.nodeList()
+		body := p.block()
 		const hookup = false // TODO(gri) enable and remove this condition
 		if hookup {
 			p.inlined[i].Inl.Set(body)
@@ -265,7 +267,7 @@ func (p *importer) typ() *Type {
 			n.Func.Inl.Set(nil)
 			if inl >= 0 {
 				if inl != len(p.inlined) {
-					panic("inlined body list inconsistent")
+					panic(fmt.Sprintf("inlined body list inconsistent: %d != %d", inl, len(p.inlined)))
 				}
 				p.inlined = append(p.inlined, n.Func)
 			}
@@ -542,6 +544,15 @@ func (p *importer) float(x *Mpflt) {
 // ----------------------------------------------------------------------------
 // Inlined function bodies
 
+func (p *importer) block() []*Node {
+	markdcl()
+	// TODO(gri) populate "scope" with function parameters so they can be found
+	//           inside the function body
+	list := p.nodeList()
+	popdcl()
+	return list
+}
+
 // parser.go:stmt_list
 func (p *importer) nodeList() []*Node {
 	c := p.int()

src/go/internal/gcimporter/bimport.go

@@ -87,7 +87,9 @@ func BImportData(imports map[string]*types.Package, data []byte, path string) (i
 	// read funcs
 	for i := p.int(); i > 0; i-- {
 		name := p.string()
-		sig := p.typ(nil).(*types.Signature)
+		params, isddd := p.paramList()
+		result, _ := p.paramList()
+		sig := types.NewSignature(nil, params, result, isddd)
 		p.int() // read and discard index of inlined function body
 		p.declare(types.NewFunc(token.NoPos, pkg, name, sig))
 	}