1// Copyright 2009 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package ir
6
7import (
8	"cmd/compile/internal/base"
9	"cmd/compile/internal/types"
10	"cmd/internal/src"
11)
12
13// Calling TypeNode converts a *types.Type to a Node shell.
14
15// A typeNode is a Node wrapper for type t.
16type typeNode struct {
17	miniNode
18	typ *types.Type
19}
20
21func newTypeNode(typ *types.Type) *typeNode {
22	n := &typeNode{typ: typ}
23	n.pos = src.NoXPos
24	n.op = OTYPE
25	n.SetTypecheck(1)
26	return n
27}
28
29func (n *typeNode) Type() *types.Type { return n.typ }
30func (n *typeNode) Sym() *types.Sym   { return n.typ.Sym() }
31
32// TypeNode returns the Node representing the type t.
33func TypeNode(t *types.Type) Node {
34	if n := t.Obj(); n != nil {
35		if n.Type() != t {
36			base.Fatalf("type skew: %v has type %v, but expected %v", n, n.Type(), t)
37		}
38		return n.(*Name)
39	}
40	return newTypeNode(t)
41}
42
43// A DynamicType represents a type expression whose exact type must be
44// computed dynamically.
45type DynamicType struct {
46	miniExpr
47
48	// RType is an expression that yields a *runtime._type value
49	// representing the asserted type.
50	//
51	// BUG(mdempsky): If ITab is non-nil, RType may be nil.
52	RType Node
53
54	// ITab is an expression that yields a *runtime.itab value
55	// representing the asserted type within the assertee expression's
56	// original interface type.
57	//
58	// ITab is only used for assertions (including type switches) from
59	// non-empty interface type to a concrete (i.e., non-interface)
60	// type. For all other assertions, ITab is nil.
61	ITab Node
62}
63
64func NewDynamicType(pos src.XPos, rtype Node) *DynamicType {
65	n := &DynamicType{RType: rtype}
66	n.pos = pos
67	n.op = ODYNAMICTYPE
68	return n
69}
70