Golang code-google-com-p-go-tools-go-types.Const类(方法)实例源码

// ConstValue returns the SSA Value denoted by the source-level named
// constant obj.  The result may be a *Const, or nil if not found.
//
func (prog *Program) ConstValue(obj *types.Const) *Const {
	// TODO(adonovan): opt: share (don't reallocate)
	// Consts for const objects and constant ast.Exprs.

	// Universal constant? {true,false,nil}
	if obj.Parent() == types.Universe {
		return NewConst(obj.Val(), obj.Type())
	}
	// Package-level named constant?
	if v := prog.packageLevelValue(obj); v != nil {
		return v.(*Const)
	}
	return NewConst(obj.Val(), obj.Type())
}

func checkConstValue(t *testing.T, prog *ssa.Program, obj *types.Const) {
	c := prog.ConstValue(obj)
	// fmt.Printf("ConstValue(%s) = %s\n", obj, c) // debugging
	if c == nil {
		t.Errorf("ConstValue(%s) == nil", obj)
		return
	}
	if !types.Identical(c.Type(), obj.Type()) {
		t.Errorf("ConstValue(%s).Type() == %s", obj, c.Type())
		return
	}
	if obj.Name() != "nil" {
		if !exact.Compare(c.Value, token.EQL, obj.Val()) {
			t.Errorf("ConstValue(%s).Value (%s) != %s",
				obj, c.Value, obj.Val())
			return
		}
	}
}