cmd/compile/internal/ir: remove unused -G=0 node types

ir.PkgName was only used by the old -G=0 frontend for representing
identifiers that refer to a package name. The new types2-based
frontends directly resolve the qualified identifier to the respective
object during IR construction.

Similarly, most of the ir.*Type nodes were only needed for
representing types in the IR prior to type checking. The new
types2-based frontends directly construct the corresponding types.Type
instead.

Exception: The internal typecheck.DeclFunc API used for
compiler-generated functions still depends on ir.FuncType, so that IR
node type is retained for now. (Eventually, we should update
typecheck.DeclFunc and callers to not depend on it, but it's not
urgent.)

Change-Id: I982f1bbd41eef5b42ce0f32676c7dc4a8ab6d0ee
Reviewed-on: https://go-review.googlesource.com/c/go/+/388538
Run-TryBot: Matthew Dempsky <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Trust: Matthew Dempsky <[email protected]>
Reviewed-by: Keith Randall <[email protected]>

Author: mdempsky

src/cmd/compile/internal/ir/copy.go

@@ -79,7 +79,7 @@ func DeepCopy(pos src.XPos, n Node) Node {
 	var edit func(Node) Node
 	edit = func(x Node) Node {
 		switch x.Op() {
-		case OPACK, ONAME, ONONAME, OLITERAL, ONIL, OTYPE:
+		case ONAME, ONONAME, OLITERAL, ONIL, OTYPE:
 			return x
 		}
 		x = Copy(x)

src/cmd/compile/internal/ir/fmt.go

@@ -202,7 +202,6 @@ var OpPrec = []int{
 	ONIL:           8,
 	ONONAME:        8,
 	OOFFSETOF:      8,
-	OPACK:          8,
 	OPANIC:         8,
 	OPAREN:         8,
 	OPRINTN:        8,
@@ -213,13 +212,7 @@ var OpPrec = []int{
 	OSTR2BYTES:     8,
 	OSTR2RUNES:     8,
 	OSTRUCTLIT:     8,
-	OTARRAY:        8,
-	OTSLICE:        8,
-	OTCHAN:         8,
 	OTFUNC:         8,
-	OTINTER:        8,
-	OTMAP:          8,
-	OTSTRUCT:       8,
 	OTYPE:          8,
 	OUNSAFEADD:     8,
 	OUNSAFESLICE:   8,
@@ -640,7 +633,7 @@ func exprFmt(n Node, s fmt.State, prec int) {
 			return
 		}
 		fallthrough
-	case OPACK, ONONAME:
+	case ONONAME:
 		fmt.Fprint(s, n.Sym())
 
 	case OLINKSYMOFFSET:
@@ -654,49 +647,6 @@ func exprFmt(n Node, s fmt.State, prec int) {
 		}
 		fmt.Fprintf(s, "%v", n.Type())
 
-	case OTSLICE:
-		n := n.(*SliceType)
-		if n.DDD {
-			fmt.Fprintf(s, "...%v", n.Elem)
-		} else {
-			fmt.Fprintf(s, "[]%v", n.Elem) // happens before typecheck
-		}
-
-	case OTARRAY:
-		n := n.(*ArrayType)
-		if n.Len == nil {
-			fmt.Fprintf(s, "[...]%v", n.Elem)
-		} else {
-			fmt.Fprintf(s, "[%v]%v", n.Len, n.Elem)
-		}
-
-	case OTMAP:
-		n := n.(*MapType)
-		fmt.Fprintf(s, "map[%v]%v", n.Key, n.Elem)
-
-	case OTCHAN:
-		n := n.(*ChanType)
-		switch n.Dir {
-		case types.Crecv:
-			fmt.Fprintf(s, "<-chan %v", n.Elem)
-
-		case types.Csend:
-			fmt.Fprintf(s, "chan<- %v", n.Elem)
-
-		default:
-			if n.Elem != nil && n.Elem.Op() == OTCHAN && n.Elem.(*ChanType).Dir == types.Crecv {
-				fmt.Fprintf(s, "chan (%v)", n.Elem)
-			} else {
-				fmt.Fprintf(s, "chan %v", n.Elem)
-			}
-		}
-
-	case OTSTRUCT:
-		fmt.Fprint(s, "<struct>")
-
-	case OTINTER:
-		fmt.Fprint(s, "<inter>")
-
 	case OTFUNC:
 		fmt.Fprint(s, "<func>")
 

src/cmd/compile/internal/ir/name.go

@@ -48,7 +48,6 @@ type Name struct {
 	Opt       interface{} // for use by escape analysis
 	Embed     *[]Embed    // list of embedded files, for ONAME var
 
-	PkgName *PkgName // real package for import . names
 	// For a local variable (not param) or extern, the initializing assignment (OAS or OAS2).
 	// For a closure var, the ONAME node of the outer captured variable.
 	// For the case-local variables of a type switch, the type switch guard (OTYPESW).
@@ -536,22 +535,3 @@ type Embed struct {
 	Pos      src.XPos
 	Patterns []string
 }
-
-// A Pack is an identifier referring to an imported package.
-type PkgName struct {
-	miniNode
-	sym  *types.Sym
-	Pkg  *types.Pkg
-	Used bool
-}
-
-func (p *PkgName) Sym() *types.Sym { return p.sym }
-
-func (*PkgName) CanBeNtype() {}
-
-func NewPkgName(pos src.XPos, sym *types.Sym, pkg *types.Pkg) *PkgName {
-	p := &PkgName{sym: sym, Pkg: pkg}
-	p.op = OPACK
-	p.pos = pos
-	return p
-}

src/cmd/compile/internal/ir/node.go

@@ -118,7 +118,6 @@ const (
 	// Also used for a qualified package identifier that hasn't been resolved yet.
 	ONONAME
 	OTYPE    // type name
-	OPACK    // import
 	OLITERAL // literal
 	ONIL     // nil
 
@@ -291,15 +290,10 @@ const (
 	OFUNCINST // instantiation of a generic function
 
 	// types
-	OTCHAN   // chan int
-	OTMAP    // map[string]int
-	OTSTRUCT // struct{}
-	OTINTER  // interface{}
 	// OTFUNC: func() - Recv is receiver field, Params is list of param fields, Results is
 	// list of result fields.
+	// TODO(mdempsky): Remove.
 	OTFUNC
-	OTARRAY // [8]int or [...]int
-	OTSLICE // []int
 
 	// misc
 	// intermediate representation of an inlined call.  Uses Init (assignments
@@ -533,7 +527,7 @@ func HasNamedResults(fn *Func) bool {
 // their usage position.
 func HasUniquePos(n Node) bool {
 	switch n.Op() {
-	case ONAME, OPACK:
+	case ONAME:
 		return false
 	case OLITERAL, ONIL, OTYPE:
 		if n.Sym() != nil {