// typeOKForCgoCall returns true if the type of arg is OK to pass to a
// C function using cgo. This is not true for Go types with embedded
// pointers.
func typeOKForCgoCall(t types.Type) bool {
if t == nil {
return true
}
switch t := t.Underlying().(type) {
case *types.Chan, *types.Map, *types.Signature, *types.Slice:
return false
case *types.Pointer:
return typeOKForCgoCall(t.Elem())
case *types.Array:
return typeOKForCgoCall(t.Elem())
case *types.Struct:
for i := 0; i < t.NumFields(); i++ {
if !typeOKForCgoCall(t.Field(i).Type()) {
return false
}
}
}
return true
}
func equalType(x, y types.Type) error {
if reflect.TypeOf(x) != reflect.TypeOf(y) {
return fmt.Errorf("unequal kinds: %T vs %T", x, y)
}
switch x := x.(type) {
case *types.Interface:
y := y.(*types.Interface)
// TODO(gri): enable separate emission of Embedded interfaces
// and ExplicitMethods then use this logic.
// if x.NumEmbeddeds() != y.NumEmbeddeds() {
// return fmt.Errorf("unequal number of embedded interfaces: %d vs %d",
// x.NumEmbeddeds(), y.NumEmbeddeds())
// }
// for i := 0; i < x.NumEmbeddeds(); i++ {
// xi := x.Embedded(i)
// yi := y.Embedded(i)
// if xi.String() != yi.String() {
// return fmt.Errorf("mismatched %th embedded interface: %s vs %s",
// i, xi, yi)
// }
// }
// if x.NumExplicitMethods() != y.NumExplicitMethods() {
// return fmt.Errorf("unequal methods: %d vs %d",
// x.NumExplicitMethods(), y.NumExplicitMethods())
// }
// for i := 0; i < x.NumExplicitMethods(); i++ {
// xm := x.ExplicitMethod(i)
// ym := y.ExplicitMethod(i)
// if xm.Name() != ym.Name() {
// return fmt.Errorf("mismatched %th method: %s vs %s", i, xm, ym)
// }
// if err := equalType(xm.Type(), ym.Type()); err != nil {
// return fmt.Errorf("mismatched %s method: %s", xm.Name(), err)
// }
// }
if x.NumMethods() != y.NumMethods() {
return fmt.Errorf("unequal methods: %d vs %d",
x.NumMethods(), y.NumMethods())
}
for i := 0; i < x.NumMethods(); i++ {
xm := x.Method(i)
ym := y.Method(i)
if xm.Name() != ym.Name() {
return fmt.Errorf("mismatched %dth method: %s vs %s", i, xm, ym)
}
if err := equalType(xm.Type(), ym.Type()); err != nil {
return fmt.Errorf("mismatched %s method: %s", xm.Name(), err)
}
}
case *types.Array:
y := y.(*types.Array)
if x.Len() != y.Len() {
return fmt.Errorf("unequal array lengths: %d vs %d", x.Len(), y.Len())
}
if err := equalType(x.Elem(), y.Elem()); err != nil {
return fmt.Errorf("array elements: %s", err)
}
case *types.Basic:
y := y.(*types.Basic)
if x.Kind() != y.Kind() {
return fmt.Errorf("unequal basic types: %s vs %s", x, y)
}
case *types.Chan:
y := y.(*types.Chan)
if x.Dir() != y.Dir() {
return fmt.Errorf("unequal channel directions: %d vs %d", x.Dir(), y.Dir())
}
if err := equalType(x.Elem(), y.Elem()); err != nil {
return fmt.Errorf("channel elements: %s", err)
}
case *types.Map:
y := y.(*types.Map)
if err := equalType(x.Key(), y.Key()); err != nil {
return fmt.Errorf("map keys: %s", err)
}
if err := equalType(x.Elem(), y.Elem()); err != nil {
return fmt.Errorf("map values: %s", err)
}
case *types.Named:
y := y.(*types.Named)
if x.String() != y.String() {
return fmt.Errorf("unequal named types: %s vs %s", x, y)
}
case *types.Pointer:
y := y.(*types.Pointer)
if err := equalType(x.Elem(), y.Elem()); err != nil {
return fmt.Errorf("pointer elements: %s", err)
}
case *types.Signature:
y := y.(*types.Signature)
if err := equalType(x.Params(), y.Params()); err != nil {
return fmt.Errorf("parameters: %s", err)
}
if err := equalType(x.Results(), y.Results()); err != nil {
return fmt.Errorf("results: %s", err)
}
if x.Variadic() != y.Variadic() {
return fmt.Errorf("unequal varidicity: %t vs %t",
x.Variadic(), y.Variadic())
}
if (x.Recv() != nil) != (y.Recv() != nil) {
return fmt.Errorf("unequal receivers: %s vs %s", x.Recv(), y.Recv())
}
if x.Recv() != nil {
// TODO(adonovan): fix: this assertion fires for interface methods.
// The type of the receiver of an interface method is a named type
// if the Package was loaded from export data, or an unnamed (interface)
// type if the Package was produced by type-checking ASTs.
// if err := equalType(x.Recv().Type(), y.Recv().Type()); err != nil {
// return fmt.Errorf("receiver: %s", err)
// }
}
case *types.Slice:
y := y.(*types.Slice)
if err := equalType(x.Elem(), y.Elem()); err != nil {
return fmt.Errorf("slice elements: %s", err)
}
case *types.Struct:
y := y.(*types.Struct)
if x.NumFields() != y.NumFields() {
return fmt.Errorf("unequal struct fields: %d vs %d",
x.NumFields(), y.NumFields())
}
for i := 0; i < x.NumFields(); i++ {
xf := x.Field(i)
yf := y.Field(i)
if xf.Name() != yf.Name() {
return fmt.Errorf("mismatched fields: %s vs %s", xf, yf)
}
if err := equalType(xf.Type(), yf.Type()); err != nil {
return fmt.Errorf("struct field %s: %s", xf.Name(), err)
}
if x.Tag(i) != y.Tag(i) {
return fmt.Errorf("struct field %s has unequal tags: %q vs %q",
xf.Name(), x.Tag(i), y.Tag(i))
}
}
case *types.Tuple:
y := y.(*types.Tuple)
if x.Len() != y.Len() {
return fmt.Errorf("unequal tuple lengths: %d vs %d", x.Len(), y.Len())
}
for i := 0; i < x.Len(); i++ {
if err := equalType(x.At(i).Type(), y.At(i).Type()); err != nil {
return fmt.Errorf("tuple element %d: %s", i, err)
}
}
}
return nil
}
// zero returns a new "zero" value of the specified type.
func zero(t types.Type) value {
switch t := t.(type) {
case *types.Basic:
if t.Kind() == types.UntypedNil {
panic("untyped nil has no zero value")
}
if t.Info()&types.IsUntyped != 0 {
// TODO(adonovan): make it an invariant that
// this is unreachable. Currently some
// constants have 'untyped' types when they
// should be defaulted by the typechecker.
t = ssa.DefaultType(t).(*types.Basic)
}
switch t.Kind() {
case types.Bool:
return false
case types.Int:
return int(0)
case types.Int8:
return int8(0)
case types.Int16:
return int16(0)
case types.Int32:
return int32(0)
case types.Int64:
return int64(0)
case types.Uint:
return uint(0)
case types.Uint8:
return uint8(0)
case types.Uint16:
return uint16(0)
case types.Uint32:
return uint32(0)
case types.Uint64:
return uint64(0)
case types.Uintptr:
return uintptr(0)
case types.Float32:
return float32(0)
case types.Float64:
return float64(0)
case types.Complex64:
return complex64(0)
case types.Complex128:
return complex128(0)
case types.String:
return ""
case types.UnsafePointer:
return unsafe.Pointer(nil)
default:
panic(fmt.Sprint("zero for unexpected type:", t))
}
case *types.Pointer:
return (*value)(nil)
case *types.Array:
a := make(array, t.Len())
for i := range a {
a[i] = zero(t.Elem())
}
return a
case *types.Named:
return zero(t.Underlying())
case *types.Interface:
return iface{} // nil type, methodset and value
case *types.Slice:
return []value(nil)
case *types.Struct:
s := make(structure, t.NumFields())
for i := range s {
s[i] = zero(t.Field(i).Type())
}
return s
case *types.Tuple:
if t.Len() == 1 {
return zero(t.At(0).Type())
}
s := make(tuple, t.Len())
for i := range s {
s[i] = zero(t.At(i).Type())
}
return s
case *types.Chan:
return chan value(nil)
case *types.Map:
if usesBuiltinMap(t.Key()) {
return map[value]value(nil)
}
return (*hashmap)(nil)
case *types.Signature:
return (*ssa.Function)(nil)
}
panic(fmt.Sprint("zero: unexpected ", t))
}
// flatten returns a list of directly contained fields in the preorder
// traversal of the type tree of t. The resulting elements are all
// scalars (basic types or pointerlike types), except for struct/array
// "identity" nodes, whose type is that of the aggregate.
//
// reflect.Value is considered pointerlike, similar to interface{}.
//
// Callers must not mutate the result.
//
func (a *analysis) flatten(t types.Type) []*fieldInfo {
fl, ok := a.flattenMemo[t]
if !ok {
switch t := t.(type) {
case *types.Named:
u := t.Underlying()
if isInterface(u) {
// Debuggability hack: don't remove
// the named type from interfaces as
// they're very verbose.
fl = append(fl, &fieldInfo{typ: t})
} else {
fl = a.flatten(u)
}
case *types.Basic,
*types.Signature,
*types.Chan,
*types.Map,
*types.Interface,
*types.Slice,
*types.Pointer:
fl = append(fl, &fieldInfo{typ: t})
case *types.Array:
fl = append(fl, &fieldInfo{typ: t}) // identity node
for _, fi := range a.flatten(t.Elem()) {
fl = append(fl, &fieldInfo{typ: fi.typ, op: true, tail: fi})
}
case *types.Struct:
fl = append(fl, &fieldInfo{typ: t}) // identity node
for i, n := 0, t.NumFields(); i < n; i++ {
f := t.Field(i)
for _, fi := range a.flatten(f.Type()) {
fl = append(fl, &fieldInfo{typ: fi.typ, op: f, tail: fi})
}
}
case *types.Tuple:
// No identity node: tuples are never address-taken.
n := t.Len()
if n == 1 {
// Don't add a fieldInfo link for singletons,
// e.g. in params/results.
fl = append(fl, a.flatten(t.At(0).Type())...)
} else {
for i := 0; i < n; i++ {
f := t.At(i)
for _, fi := range a.flatten(f.Type()) {
fl = append(fl, &fieldInfo{typ: fi.typ, op: i, tail: fi})
}
}
}
default:
panic(t)
}
a.flattenMemo[t] = fl
}
return fl
}
// hashFor computes the hash of t.
func (h Hasher) hashFor(t types.Type) uint32 {
// See Identical for rationale.
switch t := t.(type) {
case *types.Basic:
return uint32(t.Kind())
case *types.Array:
return 9043 + 2*uint32(t.Len()) + 3*h.Hash(t.Elem())
case *types.Slice:
return 9049 + 2*h.Hash(t.Elem())
case *types.Struct:
var hash uint32 = 9059
for i, n := 0, t.NumFields(); i < n; i++ {
f := t.Field(i)
if f.Anonymous() {
hash += 8861
}
hash += hashString(t.Tag(i))
hash += hashString(f.Name()) // (ignore f.Pkg)
hash += h.Hash(f.Type())
}
return hash
case *types.Pointer:
return 9067 + 2*h.Hash(t.Elem())
case *types.Signature:
var hash uint32 = 9091
if t.Variadic() {
hash *= 8863
}
return hash + 3*h.hashTuple(t.Params()) + 5*h.hashTuple(t.Results())
case *types.Interface:
var hash uint32 = 9103
for i, n := 0, t.NumMethods(); i < n; i++ {
// See go/types.identicalMethods for rationale.
// Method order is not significant.
// Ignore m.Pkg().
m := t.Method(i)
hash += 3*hashString(m.Name()) + 5*h.Hash(m.Type())
}
return hash
case *types.Map:
return 9109 + 2*h.Hash(t.Key()) + 3*h.Hash(t.Elem())
case *types.Chan:
return 9127 + 2*uint32(t.Dir()) + 3*h.Hash(t.Elem())
case *types.Named:
// Not safe with a copying GC; objects may move.
return uint32(reflect.ValueOf(t.Obj()).Pointer())
case *types.Tuple:
return h.hashTuple(t)
}
panic(t)
}