// typeAssert checks whether dynamic type of itf is instr.AssertedType.
// It returns the extracted value on success, and panics on failure,
// unless instr.CommaOk, in which case it always returns a "value,ok" tuple.
//
func typeAssert(i *interpreter, instr *ssa.TypeAssert, itf iface) value {
var v value
err := ""
if itf.t == nil {
err = fmt.Sprintf("interface conversion: interface is nil, not %s", instr.AssertedType)
} else if idst, ok := instr.AssertedType.Underlying().(*types.Interface); ok {
v = itf
err = checkInterface(i, idst, itf)
} else if types.Identical(itf.t, instr.AssertedType) {
v = itf.v // extract value
} else {
err = fmt.Sprintf("interface conversion: interface is %s, not %s", itf.t, instr.AssertedType)
}
if err != "" {
if !instr.CommaOk {
panic(err)
}
return tuple{zero(instr.AssertedType), false}
}
if instr.CommaOk {
return tuple{v, true}
}
return v
}
// computeTrackBits sets a.track to the necessary 'track' bits for the pointer queries.
func (a *analysis) computeTrackBits() {
var queryTypes []types.Type
for v := range a.config.Queries {
queryTypes = append(queryTypes, v.Type())
}
for v := range a.config.IndirectQueries {
queryTypes = append(queryTypes, mustDeref(v.Type()))
}
for _, t := range queryTypes {
switch t.Underlying().(type) {
case *types.Chan:
a.track |= trackChan
case *types.Map:
a.track |= trackMap
case *types.Pointer:
a.track |= trackPtr
case *types.Slice:
a.track |= trackSlice
case *types.Interface:
a.track = trackAll
return
}
if rVObj := a.reflectValueObj; rVObj != nil && types.Identical(t, rVObj.Type()) {
a.track = trackAll
return
}
}
}
// Set sets the map entry for key to val,
// and returns the previous entry, if any.
func (m *Map) Set(key types.Type, value interface{}) (prev interface{}) {
if m.table != nil {
hash := m.hasher.Hash(key)
bucket := m.table[hash]
var hole *entry
for i, e := range bucket {
if e.key == nil {
hole = &bucket[i]
} else if types.Identical(key, e.key) {
prev = e.value
bucket[i].value = value
return
}
}
if hole != nil {
*hole = entry{key, value} // overwrite deleted entry
} else {
m.table[hash] = append(bucket, entry{key, value})
}
} else {
if m.hasher.memo == nil {
m.hasher = MakeHasher()
}
hash := m.hasher.Hash(key)
m.table = map[uint32][]entry{hash: {entry{key, value}}}
}
m.length++
return
}
func checkEqualButNotIdentical(t *testing.T, x, y types.Type, comment string) {
if !types.Identical(x, y) {
t.Errorf("%s: not equal: %s, %s", comment, x, y)
}
if x == y {
t.Errorf("%s: identical: %v, %v", comment, x, y)
}
}
// At returns the map entry for the given key.
// The result is nil if the entry is not present.
//
func (m *Map) At(key types.Type) interface{} {
if m != nil && m.table != nil {
for _, e := range m.table[m.hasher.Hash(key)] {
if e.key != nil && types.Identical(key, e.key) {
return e.value
}
}
}
return nil
}
// Delete removes the entry with the given key, if any.
// It returns true if the entry was found.
//
func (m *Map) Delete(key types.Type) bool {
if m != nil && m.table != nil {
hash := m.hasher.Hash(key)
bucket := m.table[hash]
for i, e := range bucket {
if e.key != nil && types.Identical(key, e.key) {
// We can't compact the bucket as it
// would disturb iterators.
bucket[i] = entry{}
m.length--
return true
}
}
}
return false
}
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
}
}
}
func checkFuncValue(t *testing.T, prog *ssa.Program, obj *types.Func) {
fn := prog.FuncValue(obj)
// fmt.Printf("FuncValue(%s) = %s\n", obj, fn) // debugging
if fn == nil {
if obj.Name() != "interfaceMethod" {
t.Errorf("FuncValue(%s) == nil", obj)
}
return
}
if fnobj := fn.Object(); fnobj != obj {
t.Errorf("FuncValue(%s).Object() == %s; value was %s",
obj, fnobj, fn.Name())
return
}
if !types.Identical(fn.Type(), obj.Type()) {
t.Errorf("FuncValue(%s).Type() == %s", obj, fn.Type())
return
}
}
// isValuePreserving returns true if a conversion from ut_src to
// ut_dst is value-preserving, i.e. just a change of type.
// Precondition: neither argument is a named type.
//
func isValuePreserving(ut_src, ut_dst types.Type) bool {
// Identical underlying types?
if types.Identical(ut_dst, ut_src) {
return true
}
switch ut_dst.(type) {
case *types.Chan:
// Conversion between channel types?
_, ok := ut_src.(*types.Chan)
return ok
case *types.Pointer:
// Conversion between pointers with identical base types?
_, ok := ut_src.(*types.Pointer)
return ok
}
return false
}
// emitCompare emits to f code compute the boolean result of
// comparison comparison 'x op y'.
//
func emitCompare(f *Function, op token.Token, x, y Value, pos token.Pos) Value {
xt := x.Type().Underlying()
yt := y.Type().Underlying()
// Special case to optimise a tagless SwitchStmt so that
// these are equivalent
// switch { case e: ...}
// switch true { case e: ... }
// if e==true { ... }
// even in the case when e's type is an interface.
// TODO(adonovan): opt: generalise to x==true, false!=y, etc.
if x == vTrue && op == token.EQL {
if yt, ok := yt.(*types.Basic); ok && yt.Info()&types.IsBoolean != 0 {
return y
}
}
if types.Identical(xt, yt) {
// no conversion necessary
} else if _, ok := xt.(*types.Interface); ok {
y = emitConv(f, y, x.Type())
} else if _, ok := yt.(*types.Interface); ok {
x = emitConv(f, x, y.Type())
} else if _, ok := x.(*Const); ok {
x = emitConv(f, x, y.Type())
} else if _, ok := y.(*Const); ok {
y = emitConv(f, y, x.Type())
} else {
// other cases, e.g. channels. No-op.
}
v := &BinOp{
Op: op,
X: x,
Y: y,
}
v.setPos(pos)
v.setType(tBool)
return f.emit(v)
}
func checkVarValue(t *testing.T, prog *ssa.Program, pkg *ssa.Package, ref []ast.Node, obj *types.Var, expKind string, wantAddr bool) {
// The prefix of all assertions messages.
prefix := fmt.Sprintf("VarValue(%s @ L%d)",
obj, prog.Fset.Position(ref[0].Pos()).Line)
v, gotAddr := prog.VarValue(obj, pkg, ref)
// Kind is the concrete type of the ssa Value.
gotKind := "nil"
if v != nil {
gotKind = fmt.Sprintf("%T", v)[len("*ssa."):]
}
// fmt.Printf("%s = %v (kind %q; expect %q) wantAddr=%t gotAddr=%t\n", prefix, v, gotKind, expKind, wantAddr, gotAddr) // debugging
// Check the kinds match.
// "nil" indicates expected failure (e.g. optimized away).
if expKind != gotKind {
t.Errorf("%s concrete type == %s, want %s", prefix, gotKind, expKind)
}
// Check the types match.
// If wantAddr, the expected type is the object's address.
if v != nil {
expType := obj.Type()
if wantAddr {
expType = types.NewPointer(expType)
if !gotAddr {
t.Errorf("%s: got value, want address", prefix)
}
} else if gotAddr {
t.Errorf("%s: got address, want value", prefix)
}
if !types.Identical(v.Type(), expType) {
t.Errorf("%s.Type() == %s, want %s", prefix, v.Type(), expType)
}
}
}
// Like isTest, but checks the signature too.
func isTestSig(f *Function, prefix string, sig *types.Signature) bool {
return isTest(f.Name(), prefix) && types.Identical(f.Signature, sig)
}
func (x rtype) eq(_ types.Type, y interface{}) bool {
return types.Identical(x.t, y.(rtype).t)
}
// nil-tolerant variant of types.Identical.
func sameType(x, y types.Type) bool {
if x == nil {
return y == nil
}
return y != nil && types.Identical(x, y)
}
// Ensure that, in debug mode, we can determine the ssa.Value
// corresponding to every ast.Expr.
func TestValueForExpr(t *testing.T) {
conf := loader.Config{ParserMode: parser.ParseComments}
f, err := conf.ParseFile("testdata/valueforexpr.go", nil)
if err != nil {
t.Error(err)
return
}
conf.CreateFromFiles("main", f)
iprog, err := conf.Load()
if err != nil {
t.Error(err)
return
}
mainInfo := iprog.Created[0]
prog := ssa.Create(iprog, 0)
mainPkg := prog.Package(mainInfo.Pkg)
mainPkg.SetDebugMode(true)
mainPkg.Build()
if false {
// debugging
for _, mem := range mainPkg.Members {
if fn, ok := mem.(*ssa.Function); ok {
fn.WriteTo(os.Stderr)
}
}
}
// Find the actual AST node for each canonical position.
parenExprByPos := make(map[token.Pos]*ast.ParenExpr)
ast.Inspect(f, func(n ast.Node) bool {
if n != nil {
if e, ok := n.(*ast.ParenExpr); ok {
parenExprByPos[e.Pos()] = e
}
}
return true
})
// Find all annotations of form /*@kind*/.
for _, c := range f.Comments {
text := strings.TrimSpace(c.Text())
if text == "" || text[0] != '@' {
continue
}
text = text[1:]
pos := c.End() + 1
position := prog.Fset.Position(pos)
var e ast.Expr
if target := parenExprByPos[pos]; target == nil {
t.Errorf("%s: annotation doesn't precede ParenExpr: %q", position, text)
continue
} else {
e = target.X
}
path, _ := astutil.PathEnclosingInterval(f, pos, pos)
if path == nil {
t.Errorf("%s: can't find AST path from root to comment: %s", position, text)
continue
}
fn := ssa.EnclosingFunction(mainPkg, path)
if fn == nil {
t.Errorf("%s: can't find enclosing function", position)
continue
}
v, gotAddr := fn.ValueForExpr(e) // (may be nil)
got := strings.TrimPrefix(fmt.Sprintf("%T", v), "*ssa.")
if want := text; got != want {
t.Errorf("%s: got value %q, want %q", position, got, want)
}
if v != nil {
T := v.Type()
if gotAddr {
T = T.Underlying().(*types.Pointer).Elem() // deref
}
if !types.Identical(T, mainInfo.TypeOf(e)) {
t.Errorf("%s: got type %s, want %s", position, mainInfo.TypeOf(e), T)
}
}
}
}
func isSlice(typ types.Type, bkind types.BasicKind) bool {
t, ok := typ.Underlying().(*types.Slice)
return ok && types.Identical(t.Elem().Underlying(), types.Typ[bkind])
}
// emitConv emits to f code to convert Value val to exactly type typ,
// and returns the converted value. Implicit conversions are required
// by language assignability rules in assignments, parameter passing,
// etc. Conversions cannot fail dynamically.
//
func emitConv(f *Function, val Value, typ types.Type) Value {
t_src := val.Type()
// Identical types? Conversion is a no-op.
if types.Identical(t_src, typ) {
return val
}
ut_dst := typ.Underlying()
ut_src := t_src.Underlying()
// Just a change of type, but not value or representation?
if isValuePreserving(ut_src, ut_dst) {
c := &ChangeType{X: val}
c.setType(typ)
return f.emit(c)
}
// Conversion to, or construction of a value of, an interface type?
if _, ok := ut_dst.(*types.Interface); ok {
// Assignment from one interface type to another?
if _, ok := ut_src.(*types.Interface); ok {
c := &ChangeInterface{X: val}
c.setType(typ)
return f.emit(c)
}
// Untyped nil constant? Return interface-typed nil constant.
if ut_src == tUntypedNil {
return nilConst(typ)
}
// Convert (non-nil) "untyped" literals to their default type.
if t, ok := ut_src.(*types.Basic); ok && t.Info()&types.IsUntyped != 0 {
val = emitConv(f, val, DefaultType(ut_src))
}
f.Pkg.Prog.needMethodsOf(val.Type())
mi := &MakeInterface{X: val}
mi.setType(typ)
return f.emit(mi)
}
// Conversion of a compile-time constant value?
if c, ok := val.(*Const); ok {
if _, ok := ut_dst.(*types.Basic); ok || c.IsNil() {
// Conversion of a compile-time constant to
// another constant type results in a new
// constant of the destination type and
// (initially) the same abstract value.
// We don't truncate the value yet.
return NewConst(c.Value, typ)
}
// We're converting from constant to non-constant type,
// e.g. string -> []byte/[]rune.
}
// A representation-changing conversion?
// At least one of {ut_src,ut_dst} must be *Basic.
// (The other may be []byte or []rune.)
_, ok1 := ut_src.(*types.Basic)
_, ok2 := ut_dst.(*types.Basic)
if ok1 || ok2 {
c := &Convert{X: val}
c.setType(typ)
return f.emit(c)
}
panic(fmt.Sprintf("in %s: cannot convert %s (%s) to %s", f, val, val.Type(), typ))
}
func (fr *frame) convert(v *govalue, dsttyp types.Type) *govalue {
b := fr.builder
// If it's a stack allocated value, we'll want to compare the
// value type, not the pointer type.
srctyp := v.typ
// Get the underlying type, if any.
origdsttyp := dsttyp
dsttyp = dsttyp.Underlying()
srctyp = srctyp.Underlying()
// Identical (underlying) types? Just swap in the destination type.
if types.Identical(srctyp, dsttyp) {
return newValue(v.value, origdsttyp)
}
// Both pointer types with identical underlying types? Same as above.
if srctyp, ok := srctyp.(*types.Pointer); ok {
if dsttyp, ok := dsttyp.(*types.Pointer); ok {
srctyp := srctyp.Elem().Underlying()
dsttyp := dsttyp.Elem().Underlying()
if types.Identical(srctyp, dsttyp) {
return newValue(v.value, origdsttyp)
}
}
}
// string ->
if isString(srctyp) {
// (untyped) string -> string
// XXX should untyped strings be able to escape go/types?
if isString(dsttyp) {
return newValue(v.value, origdsttyp)
}
// string -> []byte
if isSlice(dsttyp, types.Byte) {
value := v.value
strdata := fr.builder.CreateExtractValue(value, 0, "")
strlen := fr.builder.CreateExtractValue(value, 1, "")
// Data must be copied, to prevent changes in
// the byte slice from mutating the string.
newdata := fr.createMalloc(strlen)
fr.memcpy(newdata, strdata, strlen)
struct_ := llvm.Undef(fr.types.ToLLVM(dsttyp))
struct_ = fr.builder.CreateInsertValue(struct_, newdata, 0, "")
struct_ = fr.builder.CreateInsertValue(struct_, strlen, 1, "")
struct_ = fr.builder.CreateInsertValue(struct_, strlen, 2, "")
return newValue(struct_, origdsttyp)
}
// string -> []rune
if isSlice(dsttyp, types.Rune) {
return fr.stringToRuneSlice(v)
}
}
// []byte -> string
if isSlice(srctyp, types.Byte) && isString(dsttyp) {
value := v.value
data := fr.builder.CreateExtractValue(value, 0, "")
len := fr.builder.CreateExtractValue(value, 1, "")
// Data must be copied, to prevent changes in
// the byte slice from mutating the string.
newdata := fr.createMalloc(len)
fr.memcpy(newdata, data, len)
struct_ := llvm.Undef(fr.types.ToLLVM(types.Typ[types.String]))
struct_ = fr.builder.CreateInsertValue(struct_, newdata, 0, "")
struct_ = fr.builder.CreateInsertValue(struct_, len, 1, "")
return newValue(struct_, types.Typ[types.String])
}
// []rune -> string
if isSlice(srctyp, types.Rune) && isString(dsttyp) {
return fr.runeSliceToString(v)
}
// rune -> string
if isString(dsttyp) && isInteger(srctyp) {
return fr.runeToString(v)
}
// Unsafe pointer conversions.
llvm_type := fr.types.ToLLVM(dsttyp)
if dsttyp == types.Typ[types.UnsafePointer] { // X -> unsafe.Pointer
if _, isptr := srctyp.(*types.Pointer); isptr {
return newValue(v.value, origdsttyp)
} else if srctyp == types.Typ[types.Uintptr] {
value := b.CreateIntToPtr(v.value, llvm_type, "")
return newValue(value, origdsttyp)
}
} else if srctyp == types.Typ[types.UnsafePointer] { // unsafe.Pointer -> X
if _, isptr := dsttyp.(*types.Pointer); isptr {
return newValue(v.value, origdsttyp)
} else if dsttyp == types.Typ[types.Uintptr] {
value := b.CreatePtrToInt(v.value, llvm_type, "")
return newValue(value, origdsttyp)
}
}
lv := v.value
srcType := lv.Type()
switch srcType.TypeKind() {
case llvm.IntegerTypeKind:
switch llvm_type.TypeKind() {
case llvm.IntegerTypeKind:
srcBits := srcType.IntTypeWidth()
dstBits := llvm_type.IntTypeWidth()
delta := srcBits - dstBits
switch {
case delta < 0:
if !isUnsigned(srctyp) {
lv = b.CreateSExt(lv, llvm_type, "")
} else {
lv = b.CreateZExt(lv, llvm_type, "")
}
case delta > 0:
lv = b.CreateTrunc(lv, llvm_type, "")
}
return newValue(lv, origdsttyp)
case llvm.FloatTypeKind, llvm.DoubleTypeKind:
if !isUnsigned(v.Type()) {
lv = b.CreateSIToFP(lv, llvm_type, "")
} else {
lv = b.CreateUIToFP(lv, llvm_type, "")
}
return newValue(lv, origdsttyp)
}
case llvm.DoubleTypeKind:
switch llvm_type.TypeKind() {
case llvm.FloatTypeKind:
lv = b.CreateFPTrunc(lv, llvm_type, "")
return newValue(lv, origdsttyp)
case llvm.IntegerTypeKind:
if !isUnsigned(dsttyp) {
lv = b.CreateFPToSI(lv, llvm_type, "")
} else {
lv = b.CreateFPToUI(lv, llvm_type, "")
}
return newValue(lv, origdsttyp)
}
case llvm.FloatTypeKind:
switch llvm_type.TypeKind() {
case llvm.DoubleTypeKind:
lv = b.CreateFPExt(lv, llvm_type, "")
return newValue(lv, origdsttyp)
case llvm.IntegerTypeKind:
if !isUnsigned(dsttyp) {
lv = b.CreateFPToSI(lv, llvm_type, "")
} else {
lv = b.CreateFPToUI(lv, llvm_type, "")
}
return newValue(lv, origdsttyp)
}
}
// Complex -> complex. Complexes are only convertible to other
// complexes, contant conversions aside. So we can just check the
// source type here; given that the types are not identical
// (checked above), we can assume the destination type is the alternate
// complex type.
if isComplex(srctyp) {
var fpcast func(llvm.Builder, llvm.Value, llvm.Type, string) llvm.Value
var fptype llvm.Type
if srctyp == types.Typ[types.Complex64] {
fpcast = (llvm.Builder).CreateFPExt
fptype = llvm.DoubleType()
} else {
fpcast = (llvm.Builder).CreateFPTrunc
fptype = llvm.FloatType()
}
if fpcast != nil {
realv := b.CreateExtractValue(lv, 0, "")
imagv := b.CreateExtractValue(lv, 1, "")
realv = fpcast(b, realv, fptype, "")
imagv = fpcast(b, imagv, fptype, "")
lv = llvm.Undef(fr.types.ToLLVM(dsttyp))
lv = b.CreateInsertValue(lv, realv, 0, "")
lv = b.CreateInsertValue(lv, imagv, 1, "")
return newValue(lv, origdsttyp)
}
}
panic(fmt.Sprintf("unimplemented conversion: %s (%s) -> %s", v.typ, lv.Type(), origdsttyp))
}