go/internal/gccgoimporter: support embedded field in pointer loop

Backport of https://golang.org/cl/194440.  Original description:
    
        If an embedded field refers to a type via a pointer, the parser needs
        to know the name of the embedded field. It is possible that the
        pointer type is not yet resolved. This CL fixes the parser to handle
        that case by setting the pointer element type to the unresolved named
        type while the pointer is being resolved.
    
    Updates golang/go#34182
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/194562

From-SVN: r275606

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-68038b4fdf1456482af986cb05dcf3121bd43ffc
+556451586b10584e4778694c84b03d0ecbbab150
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/go/internal/gccgoimporter/importer_test.go

@@ -96,6 +96,7 @@ var importerTests = [...]importerTest{
 	{pkgpath: "issue29198", name: "FooServer", gccgoVersion: 7, want: "type FooServer struct{FooServer *FooServer; user string; ctx context.Context}"},
 	{pkgpath: "issue30628", name: "Apple", want: "type Apple struct{hey sync.RWMutex; x int; RQ [517]struct{Count uintptr; NumBytes uintptr; Last uintptr}}"},
 	{pkgpath: "issue31540", name: "S", gccgoVersion: 7, want: "type S struct{b int; map[Y]Z}"},
+	{pkgpath: "issue34182", name: "T1", want: "type T1 struct{f *T2}"},
 }
 
 func TestGoxImporter(t *testing.T) {

libgo/go/go/internal/gccgoimporter/parser.go

@@ -254,7 +254,7 @@ func (p *parser) parseField(pkg *types.Package) (field *types.Var, tag string) {
 			case *types.Named:
 				name = typ.Obj().Name()
 			default:
-				p.error("anonymous field expected")
+				p.error("embedded field expected")
 			}
 		}
 	}
@@ -469,8 +469,12 @@ func (p *parser) reserve(n int) {
 	}
 }
 
-// update sets the type map entries for the given type numbers nlist to t.
-func (p *parser) update(t types.Type, nlist []int) {
+// update sets the type map entries for the entries in nlist to t.
+// An entry in nlist can be a type number in p.typeList,
+// used to resolve named types, or it can be a *types.Pointer,
+// used to resolve pointers to named types in case they are referenced
+// by embedded fields.
+func (p *parser) update(t types.Type, nlist []interface{}) {
 	if len(nlist) != 0 {
 		if t == reserved {
 			p.errorf("internal error: update(%v) invoked on reserved", nlist)
@@ -480,20 +484,34 @@ func (p *parser) update(t types.Type, nlist []int) {
 		}
 	}
 	for _, n := range nlist {
-		if p.typeList[n] == t {
-			continue
+		switch n := n.(type) {
+		case int:
+			if p.typeList[n] == t {
+				continue
+			}
+			if p.typeList[n] != reserved {
+				p.errorf("internal error: update(%v): %d not reserved", nlist, n)
+			}
+			p.typeList[n] = t
+		case *types.Pointer:
+			if *n != (types.Pointer{}) {
+				elem := n.Elem()
+				if elem == t {
+					continue
+				}
+				p.errorf("internal error: update: pointer already set to %v, expected %v", elem, t)
+			}
+			*n = *types.NewPointer(t)
+		default:
+			p.errorf("internal error: %T on nlist", n)
 		}
-		if p.typeList[n] != reserved {
-			p.errorf("internal error: update(%v): %d not reserved", nlist, n)
-		}
-		p.typeList[n] = t
 	}
 }
 
 // NamedType = TypeName [ "=" ] Type { Method } .
 // TypeName  = ExportedName .
 // Method    = "func" "(" Param ")" Name ParamList ResultList [InlineBody] ";" .
-func (p *parser) parseNamedType(nlist []int) types.Type {
+func (p *parser) parseNamedType(nlist []interface{}) types.Type {
 	pkg, name := p.parseExportedName()
 	scope := pkg.Scope()
 	obj := scope.Lookup(name)
@@ -504,7 +522,7 @@ func (p *parser) parseNamedType(nlist []int) types.Type {
 	// type alias
 	if p.tok == '=' {
 		p.next()
-		p.aliases[nlist[len(nlist)-1]] = name
+		p.aliases[nlist[len(nlist)-1].(int)] = name
 		if obj != nil {
 			// use the previously imported (canonical) type
 			t := obj.Type()
@@ -603,7 +621,7 @@ func (p *parser) parseInt() int {
 }
 
 // ArrayOrSliceType = "[" [ int ] "]" Type .
-func (p *parser) parseArrayOrSliceType(pkg *types.Package, nlist []int) types.Type {
+func (p *parser) parseArrayOrSliceType(pkg *types.Package, nlist []interface{}) types.Type {
 	p.expect('[')
 	if p.tok == ']' {
 		p.next()
@@ -626,7 +644,7 @@ func (p *parser) parseArrayOrSliceType(pkg *types.Package, nlist []int) types.Ty
 }
 
 // MapType = "map" "[" Type "]" Type .
-func (p *parser) parseMapType(pkg *types.Package, nlist []int) types.Type {
+func (p *parser) parseMapType(pkg *types.Package, nlist []interface{}) types.Type {
 	p.expectKeyword("map")
 
 	t := new(types.Map)
@@ -642,7 +660,7 @@ func (p *parser) parseMapType(pkg *types.Package, nlist []int) types.Type {
 }
 
 // ChanType = "chan" ["<-" | "-<"] Type .
-func (p *parser) parseChanType(pkg *types.Package, nlist []int) types.Type {
+func (p *parser) parseChanType(pkg *types.Package, nlist []interface{}) types.Type {
 	p.expectKeyword("chan")
 
 	t := new(types.Chan)
@@ -669,7 +687,7 @@ func (p *parser) parseChanType(pkg *types.Package, nlist []int) types.Type {
 }
 
 // StructType = "struct" "{" { Field } "}" .
-func (p *parser) parseStructType(pkg *types.Package, nlist []int) types.Type {
+func (p *parser) parseStructType(pkg *types.Package, nlist []interface{}) types.Type {
 	p.expectKeyword("struct")
 
 	t := new(types.Struct)
@@ -736,7 +754,7 @@ func (p *parser) parseResultList(pkg *types.Package) *types.Tuple {
 }
 
 // FunctionType = ParamList ResultList .
-func (p *parser) parseFunctionType(pkg *types.Package, nlist []int) *types.Signature {
+func (p *parser) parseFunctionType(pkg *types.Package, nlist []interface{}) *types.Signature {
 	t := new(types.Signature)
 	p.update(t, nlist)
 
@@ -776,7 +794,7 @@ func (p *parser) parseFunc(pkg *types.Package) *types.Func {
 }
 
 // InterfaceType = "interface" "{" { ("?" Type | Func) ";" } "}" .
-func (p *parser) parseInterfaceType(pkg *types.Package, nlist []int) types.Type {
+func (p *parser) parseInterfaceType(pkg *types.Package, nlist []interface{}) types.Type {
 	p.expectKeyword("interface")
 
 	t := new(types.Interface)
@@ -805,7 +823,7 @@ func (p *parser) parseInterfaceType(pkg *types.Package, nlist []int) types.Type
 }
 
 // PointerType = "*" ("any" | Type) .
-func (p *parser) parsePointerType(pkg *types.Package, nlist []int) types.Type {
+func (p *parser) parsePointerType(pkg *types.Package, nlist []interface{}) types.Type {
 	p.expect('*')
 	if p.tok == scanner.Ident {
 		p.expectKeyword("any")
@@ -817,13 +835,13 @@ func (p *parser) parsePointerType(pkg *types.Package, nlist []int) types.Type {
 	t := new(types.Pointer)
 	p.update(t, nlist)
 
-	*t = *types.NewPointer(p.parseType(pkg))
+	*t = *types.NewPointer(p.parseType(pkg, t))
 
 	return t
 }
 
 // TypeSpec = NamedType | MapType | ChanType | StructType | InterfaceType | PointerType | ArrayOrSliceType | FunctionType .
-func (p *parser) parseTypeSpec(pkg *types.Package, nlist []int) types.Type {
+func (p *parser) parseTypeSpec(pkg *types.Package, nlist []interface{}) types.Type {
 	switch p.tok {
 	case scanner.String:
 		return p.parseNamedType(nlist)
@@ -912,14 +930,14 @@ func lookupBuiltinType(typ int) types.Type {
 //
 // parseType updates the type map to t for all type numbers n.
 //
-func (p *parser) parseType(pkg *types.Package, n ...int) types.Type {
+func (p *parser) parseType(pkg *types.Package, n ...interface{}) types.Type {
 	p.expect('<')
 	t, _ := p.parseTypeAfterAngle(pkg, n...)
 	return t
 }
 
 // (*parser).Type after reading the "<".
-func (p *parser) parseTypeAfterAngle(pkg *types.Package, n ...int) (t types.Type, n1 int) {
+func (p *parser) parseTypeAfterAngle(pkg *types.Package, n ...interface{}) (t types.Type, n1 int) {
 	p.expectKeyword("type")
 
 	n1 = 0
@@ -962,7 +980,7 @@ func (p *parser) parseTypeAfterAngle(pkg *types.Package, n ...int) (t types.Type
 // parseTypeExtended is identical to parseType, but if the type in
 // question is a saved type, returns the index as well as the type
 // pointer (index returned is zero if we parsed a builtin).
-func (p *parser) parseTypeExtended(pkg *types.Package, n ...int) (t types.Type, n1 int) {
+func (p *parser) parseTypeExtended(pkg *types.Package, n ...interface{}) (t types.Type, n1 int) {
 	p.expect('<')
 	t, n1 = p.parseTypeAfterAngle(pkg, n...)
 	return
@@ -1044,12 +1062,12 @@ func (p *parser) parseTypes(pkg *types.Package) {
 	}
 
 	for i := 1; i < int(exportedp1); i++ {
-		p.parseSavedType(pkg, i, []int{})
+		p.parseSavedType(pkg, i, nil)
 	}
 }
 
 // parseSavedType parses one saved type definition.
-func (p *parser) parseSavedType(pkg *types.Package, i int, nlist []int) {
+func (p *parser) parseSavedType(pkg *types.Package, i int, nlist []interface{}) {
 	defer func(s *scanner.Scanner, tok rune, lit string) {
 		p.scanner = s
 		p.tok = tok

libgo/go/go/internal/gccgoimporter/testdata/issue34182.go

@@ -0,0 +1,17 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package issue34182
+
+type T1 struct {
+	f *T2
+}
+
+type T2 struct {
+	f T3
+}
+
+type T3 struct {
+	*T2
+}

libgo/go/go/internal/gccgoimporter/testdata/issue34182.gox

@@ -0,0 +1,13 @@
+v3;
+package issue34182
+pkgpath issue34182
+init issue34182 ~go.issue34182
+types 8 4 21 21 21 17 30 45 45
+type 1 "T1" <type 6>
+type 2 "T2" <type 7>
+type 3 "T3" <type 5>
+type 4 *<type 2>
+type 5 struct { ? <type 4>; }
+type 6 struct { .go.issue34182.f <type 4>; }
+type 7 struct { .go.issue34182.f <type 3>; }
+checksum FF02C49BAF44B06C087ED4E573F7CC880C79C208