func newVariable(name string, addr uintptr, dwarfType dwarf.Type, thread *Thread) (*Variable, error) {
v := &Variable{
Name: name,
Addr: addr,
dwarfType: dwarfType,
thread: thread,
Type: dwarfType.String(),
}
switch t := dwarfType.(type) {
case *dwarf.StructType:
if strings.HasPrefix(t.StructName, "[]") {
err := v.loadSliceInfo(t)
if err != nil {
return nil, err
}
}
case *dwarf.ArrayType:
v.base = v.Addr
v.Len = t.Count
v.Cap = -1
v.fieldType = t.Type
v.stride = 0
if t.Count > 0 {
v.stride = t.ByteSize / t.Count
}
}
return v, nil
}
func (v *Variable) isType(typ dwarf.Type, kind reflect.Kind) error {
if v.DwarfType != nil {
if typ != nil && typ.String() != v.RealType.String() {
return fmt.Errorf("can not convert value of type %s to %s", v.DwarfType.String(), typ.String())
}
return nil
}
if typ == nil {
return nil
}
if v == nilVariable {
switch kind {
case reflect.Slice, reflect.Map, reflect.Func, reflect.Ptr, reflect.Chan, reflect.Interface:
return nil
default:
return fmt.Errorf("mismatched types nil and %s", typ.String())
}
}
converr := fmt.Errorf("can not convert %s constant to %s", v.Value, typ.String())
if v.Value == nil {
return converr
}
switch t := typ.(type) {
case *dwarf.IntType:
if v.Value.Kind() != constant.Int {
return converr
}
case *dwarf.UintType:
if v.Value.Kind() != constant.Int {
return converr
}
case *dwarf.FloatType:
if (v.Value.Kind() != constant.Int) && (v.Value.Kind() != constant.Float) {
return converr
}
case *dwarf.BoolType:
if v.Value.Kind() != constant.Bool {
return converr
}
case *dwarf.StructType:
if t.StructName != "string" {
return converr
}
if v.Value.Kind() != constant.String {
return converr
}
case *dwarf.ComplexType:
if v.Value.Kind() != constant.Complex && v.Value.Kind() != constant.Float && v.Value.Kind() != constant.Int {
return converr
}
default:
return converr
}
return nil
}
// Eval type cast expressions
func (scope *EvalScope) evalTypeCast(node *ast.CallExpr) (*Variable, error) {
if len(node.Args) != 1 {
return nil, fmt.Errorf("wrong number of arguments for a type cast")
}
argv, err := scope.evalAST(node.Args[0])
if err != nil {
return nil, err
}
argv.loadValue()
if argv.Unreadable != nil {
return nil, argv.Unreadable
}
fnnode := node.Fun
// remove all enclosing parenthesis from the type name
for {
p, ok := fnnode.(*ast.ParenExpr)
if !ok {
break
}
fnnode = p.X
}
var typ dwarf.Type
if snode, ok := fnnode.(*ast.StarExpr); ok {
// Pointer types only appear in the dwarf informations when
// a pointer to the type is used in the target program, here
// we create a pointer type on the fly so that the user can
// specify a pointer to any variable used in the target program
ptyp, err := scope.findType(exprToString(snode.X))
if err != nil {
return nil, err
}
typ = &dwarf.PtrType{dwarf.CommonType{int64(scope.Thread.dbp.arch.PtrSize()), exprToString(fnnode)}, ptyp}
} else {
typ, err = scope.findType(exprToString(fnnode))
if err != nil {
return nil, err
}
}
// only supports cast of integer constants into pointers
ptyp, isptrtyp := typ.(*dwarf.PtrType)
if !isptrtyp {
return nil, fmt.Errorf("can not convert \"%s\" to %s", exprToString(node.Args[0]), typ.String())
}
switch argv.Kind {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
// ok
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
// ok
default:
return nil, fmt.Errorf("can not convert \"%s\" to %s", exprToString(node.Args[0]), typ.String())
}
n, _ := constant.Int64Val(argv.Value)
v := newVariable("", 0, ptyp, scope.Thread)
v.Children = []Variable{*newVariable("", uintptr(n), ptyp.Type, scope.Thread)}
return v, nil
}
