func TestNextConcurrentVariant2(t *testing.T) {
	// Just like TestNextConcurrent but instead of removing the initial breakpoint we check that when it happens is for other goroutines
	testcases := []nextTest{
		{8, 9},
		{9, 10},
		{10, 11},
	}
	withTestProcess("parallel_next", t, func(p *Process, fixture protest.Fixture) {
		_, err := setFunctionBreakpoint(p, "main.sayhi")
		assertNoError(err, t, "SetBreakpoint")
		assertNoError(p.Continue(), t, "Continue")
		f, ln := currentLineNumber(p, t)
		initV, err := evalVariable(p, "n")
		initVval, _ := constant.Int64Val(initV.Value)
		assertNoError(err, t, "EvalVariable")
		for _, tc := range testcases {
			g, err := p.CurrentThread.GetG()
			assertNoError(err, t, "GetG()")
			if p.SelectedGoroutine.ID != g.ID {
				t.Fatalf("SelectedGoroutine not CurrentThread's goroutine: %d %d", g.ID, p.SelectedGoroutine.ID)
			}
			if ln != tc.begin {
				t.Fatalf("Program not stopped at correct spot expected %d was %s:%d", tc.begin, filepath.Base(f), ln)
			}
			assertNoError(p.Next(), t, "Next() returned an error")
			var vval int64
			for {
				v, err := evalVariable(p, "n")
				assertNoError(err, t, "EvalVariable")
				vval, _ = constant.Int64Val(v.Value)
				if p.CurrentThread.CurrentBreakpoint == nil {
					if vval != initVval {
						t.Fatal("Did not end up on same goroutine")
					}
					break
				} else {
					if vval == initVval {
						t.Fatal("Initial breakpoint triggered twice for the same goroutine")
					}
					assertNoError(p.Continue(), t, "Continue 2")
				}
			}
			f, ln = currentLineNumber(p, t)
			if ln != tc.end {
				t.Fatalf("Program did not continue to correct next location expected %d was %s:%d", tc.end, filepath.Base(f), ln)
			}
		}
	})
}

// goVal returns the Go value for val, or nil.
func goVal(val constant.Value) interface{} {
	// val should exist, but be conservative and check
	if val == nil {
		return nil
	}
	// Match implementation restriction of other compilers.
	// gc only checks duplicates for integer, floating-point
	// and string values, so only create Go values for these
	// types.
	switch val.Kind() {
	case constant.Int:
		if x, ok := constant.Int64Val(val); ok {
			return x
		}
		if x, ok := constant.Uint64Val(val); ok {
			return x
		}
	case constant.Float:
		if x, ok := constant.Float64Val(val); ok {
			return x
		}
	case constant.String:
		return constant.StringVal(val)
	}
	return nil
}

func (g *javaGen) genConst(o *types.Const) {
	// TODO(hyangah): should const names use upper cases + "_"?
	// TODO(hyangah): check invalid names.
	jType := g.javaType(o.Type())
	val := o.Val().String()
	switch b := o.Type().(*types.Basic); b.Kind() {
	case types.Int64, types.UntypedInt:
		i, exact := constant.Int64Val(o.Val())
		if !exact {
			g.errorf("const value %s for %s cannot be represented as %s", val, o.Name(), jType)
			return
		}
		val = fmt.Sprintf("%dL", i)

	case types.Float32:
		f, _ := constant.Float32Val(o.Val())
		val = fmt.Sprintf("%gf", f)

	case types.Float64, types.UntypedFloat:
		f, _ := constant.Float64Val(o.Val())
		if math.IsInf(f, 0) || math.Abs(f) > math.MaxFloat64 {
			g.errorf("const value %s for %s cannot be represented as %s", val, o.Name(), jType)
			return
		}
		val = fmt.Sprintf("%g", f)
	}
	g.Printf("public static final %s %s = %s;\n", g.javaType(o.Type()), o.Name(), val)
}

func TestPointerSetting(t *testing.T) {
	withTestProcess("testvariables3", t, func(p *Process, fixture protest.Fixture) {
		assertNoError(p.Continue(), t, "Continue() returned an error")

		pval := func(n int64) {
			variable, err := evalVariable(p, "p1")
			assertNoError(err, t, "EvalVariable()")
			c0val, _ := constant.Int64Val(variable.Children[0].Value)
			if c0val != n {
				t.Fatalf("Wrong value of p1, *%d expected *%d", c0val, n)
			}
		}

		pval(1)

		// change p1 to point to i2
		scope, err := p.CurrentThread.Scope()
		assertNoError(err, t, "Scope()")
		i2addr, err := scope.EvalExpression("i2")
		assertNoError(err, t, "EvalExpression()")
		assertNoError(setVariable(p, "p1", fmt.Sprintf("(*int)(0x%x)", i2addr.Addr)), t, "SetVariable()")
		pval(2)

		// change the value of i2 check that p1 also changes
		assertNoError(setVariable(p, "i2", "5"), t, "SetVariable()")
		pval(5)
	})
}

func (p *exporter) value(x constant.Value) {
	if trace {
		p.tracef("value { ")
		defer p.tracef("} ")
	}

	switch kind := x.Kind(); kind {
	case constant.Bool:
		tag := falseTag
		if constant.BoolVal(x) {
			tag = trueTag
		}
		p.int(tag)
	case constant.Int:
		if i, ok := constant.Int64Val(x); ok {
			p.int(int64Tag)
			p.int64(i)
			return
		}
		p.int(floatTag)
		p.float(x)
	case constant.Float:
		p.int(fractionTag)
		p.fraction(x)
	case constant.Complex:
		p.int(complexTag)
		p.fraction(constant.Real(x))
		p.fraction(constant.Imag(x))
	case constant.String:
		p.int(stringTag)
		p.string(constant.StringVal(x))
	default:
		panic(fmt.Sprintf("unexpected value kind %d", kind))
	}
}

func (n *Node) Val() Val {
	var expr ast.Expr
	var ok bool
	if expr, ok = n.Node.(ast.Expr); ok {
		var typeAndValue types.TypeAndValue
		if typeAndValue, ok = n.Ctx.fn.Types[expr]; ok {
			if typeAndValue.Value == nil {
				panic("internal compiler error")
			}
			if typeAndValue.Value.Kind() != constant.Int {
				panic("unimplemented")
			}
			if i64, exact := constant.Int64Val(typeAndValue.Value); exact {
				mpInt := Mpint{}
				mpInt.Val = *big.NewInt(i64)
				val := Val{}
				val.U = &mpInt
				return val
			} else {
				panic("internal compiler error")
			}
		} else {
			panic("internal compiler error")
		}
	} else if _, ok = n.Node.(*ast.BasicLit); ok {
		panic("unimplemented")

	} else {
		// TODO: other ast.*
		return Val{}
	}
}

func (v *Variable) setValue(y *Variable) error {
	var err error
	switch v.Kind {
	case reflect.Float32, reflect.Float64:
		f, _ := constant.Float64Val(y.Value)
		err = v.writeFloatRaw(f, v.RealType.Size())
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		n, _ := constant.Int64Val(y.Value)
		err = v.writeUint(uint64(n), v.RealType.Size())
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		n, _ := constant.Uint64Val(y.Value)
		err = v.writeUint(n, v.RealType.Size())
	case reflect.Bool:
		err = v.writeBool(constant.BoolVal(y.Value))
	case reflect.Complex64, reflect.Complex128:
		real, _ := constant.Float64Val(constant.Real(y.Value))
		imag, _ := constant.Float64Val(constant.Imag(y.Value))
		err = v.writeComplex(real, imag, v.RealType.Size())
	default:
		fmt.Printf("default\n")
		if t, isptr := v.RealType.(*dwarf.PtrType); isptr {
			err = v.writeUint(uint64(y.Children[0].Addr), int64(t.ByteSize))
		} else {
			return fmt.Errorf("can not set variables of type %s (not implemented)", v.Kind.String())
		}
	}

	return err
}

func (v *Variable) loadSliceInfo(t *dwarf.SliceType) {
	v.mem = cacheMemory(v.mem, v.Addr, int(t.Size()))

	var err error
	for _, f := range t.Field {
		switch f.Name {
		case "array":
			var base uint64
			base, err = readUintRaw(v.mem, uintptr(int64(v.Addr)+f.ByteOffset), f.Type.Size())
			if err == nil {
				v.Base = uintptr(base)
				// Dereference array type to get value type
				ptrType, ok := f.Type.(*dwarf.PtrType)
				if !ok {
					v.Unreadable = fmt.Errorf("Invalid type %s in slice array", f.Type)
					return
				}
				v.fieldType = ptrType.Type
			}
		case "len":
			lstrAddr, _ := v.toField(f)
			lstrAddr.loadValue(loadSingleValue)
			err = lstrAddr.Unreadable
			if err == nil {
				v.Len, _ = constant.Int64Val(lstrAddr.Value)
			}
		case "cap":
			cstrAddr, _ := v.toField(f)
			cstrAddr.loadValue(loadSingleValue)
			err = cstrAddr.Unreadable
			if err == nil {
				v.Cap, _ = constant.Int64Val(cstrAddr.Value)
			}
		}
		if err != nil {
			v.Unreadable = err
			return
		}
	}

	v.stride = v.fieldType.Size()
	if t, ok := v.fieldType.(*dwarf.PtrType); ok {
		v.stride = t.ByteSize
	}

	return
}

func (v *Variable) loadSliceInfo(t *dwarf.StructType) {
	var err error
	for _, f := range t.Field {
		switch f.Name {
		case "array":
			var base uint64
			base, err = v.thread.readUintRaw(uintptr(int64(v.Addr)+f.ByteOffset), int64(v.thread.dbp.arch.PtrSize()))
			if err == nil {
				v.base = uintptr(base)
				// Dereference array type to get value type
				ptrType, ok := f.Type.(*dwarf.PtrType)
				if !ok {
					v.Unreadable = fmt.Errorf("Invalid type %s in slice array", f.Type)
					return
				}
				v.fieldType = ptrType.Type
			}
		case "len":
			lstrAddr, _ := v.toField(f)
			lstrAddr.loadValue()
			err = lstrAddr.Unreadable
			if err == nil {
				v.Len, _ = constant.Int64Val(lstrAddr.Value)
			}
		case "cap":
			cstrAddr, _ := v.toField(f)
			cstrAddr.loadValue()
			err = cstrAddr.Unreadable
			if err == nil {
				v.Cap, _ = constant.Int64Val(cstrAddr.Value)
			}
		}
		if err != nil {
			v.Unreadable = err
			return
		}
	}

	v.stride = v.fieldType.Size()
	if _, ok := v.fieldType.(*dwarf.PtrType); ok {
		v.stride = int64(v.thread.dbp.arch.PtrSize())
	}

	return
}

// asInt64 returns the value as a 64-bit integer if possible, or returns an
// error if not possible.
func (expr *NumVal) asInt64() (int64, error) {
	intVal, ok := expr.asConstantInt()
	if !ok {
		return 0, fmt.Errorf("cannot represent %v as an int", expr.Value)
	}
	i, exact := constant.Int64Val(intVal)
	if !exact {
		return 0, fmt.Errorf("representing %v as an int would overflow", intVal)
	}
	return i, nil
}

// asInt64 returns the value as a 64-bit integer if possible, or returns an
// error if not possible. The method will set expr.resInt to the value of
// this int64 if it is successful, avoiding the need to call the method again.
func (expr *NumVal) asInt64() (int64, error) {
	intVal, ok := expr.asConstantInt()
	if !ok {
		return 0, errConstNotInt
	}
	i, exact := constant.Int64Val(intVal)
	if !exact {
		return 0, errConstOutOfRange
	}
	expr.resInt = DInt(i)
	return i, nil
}

// Conversion type-checks the conversion T(x).
// The result is in x.
func (check *Checker) conversion(x *operand, T Type) {
	constArg := x.mode == constant_

	var ok bool
	switch {
	case constArg && isConstType(T):
		// constant conversion
		switch t := T.Underlying().(*Basic); {
		case representableConst(x.val, check.conf, t.kind, &x.val):
			ok = true
		case isInteger(x.typ) && isString(t):
			codepoint := int64(-1)
			if i, ok := constant.Int64Val(x.val); ok {
				codepoint = i
			}
			// If codepoint < 0 the absolute value is too large (or unknown) for
			// conversion. This is the same as converting any other out-of-range
			// value - let string(codepoint) do the work.
			x.val = constant.MakeString(string(codepoint))
			ok = true
		}
	case x.convertibleTo(check.conf, T):
		// non-constant conversion
		x.mode = value
		ok = true
	}

	if !ok {
		check.errorf(x.pos(), "cannot convert %s to %s", x, T)
		x.mode = invalid
		return
	}

	// The conversion argument types are final. For untyped values the
	// conversion provides the type, per the spec: "A constant may be
	// given a type explicitly by a constant declaration or conversion,...".
	final := x.typ
	if isUntyped(x.typ) {
		final = T
		// - For conversions to interfaces, use the argument's default type.
		// - For conversions of untyped constants to non-constant types, also
		//   use the default type (e.g., []byte("foo") should report string
		//   not []byte as type for the constant "foo").
		// - Keep untyped nil for untyped nil arguments.
		if IsInterface(T) || constArg && !isConstType(T) {
			final = defaultType(x.typ)
		}
		check.updateExprType(x.expr, final, true)
	}

	x.typ = T
}

func (gvar *Variable) parseG() (*G, error) {
	mem := gvar.mem
	dbp := gvar.dbp
	gaddr := uint64(gvar.Addr)
	_, deref := gvar.RealType.(*dwarf.PtrType)

	initialInstructions := make([]byte, dbp.arch.PtrSize()+1)
	initialInstructions[0] = op.DW_OP_addr
	binary.LittleEndian.PutUint64(initialInstructions[1:], gaddr)
	if deref {
		gaddrbytes, err := mem.readMemory(uintptr(gaddr), dbp.arch.PtrSize())
		if err != nil {
			return nil, fmt.Errorf("error derefing *G %s", err)
		}
		initialInstructions = append([]byte{op.DW_OP_addr}, gaddrbytes...)
		gaddr = binary.LittleEndian.Uint64(gaddrbytes)
		if gaddr == 0 {
			id := 0
			if thread, ok := mem.(*Thread); ok {
				id = thread.ID
			}
			return nil, NoGError{tid: id}
		}
	}
	if gaddr == 0 {
		return nil, NoGError{}
	}
	gvar.loadValue()
	if gvar.Unreadable != nil {
		return nil, gvar.Unreadable
	}
	schedVar := gvar.toFieldNamed("sched")
	pc, _ := constant.Int64Val(schedVar.toFieldNamed("pc").Value)
	sp, _ := constant.Int64Val(schedVar.toFieldNamed("sp").Value)
	id, _ := constant.Int64Val(gvar.toFieldNamed("goid").Value)
	gopc, _ := constant.Int64Val(gvar.toFieldNamed("gopc").Value)
	waitReason := constant.StringVal(gvar.toFieldNamed("waitreason").Value)
	d := gvar.toFieldNamed("_defer")
	deferPC := int64(0)
	fnvar := d.toFieldNamed("fn")
	if fnvar != nil {
		fnvalvar := fnvar.toFieldNamed("fn")
		deferPC, _ = constant.Int64Val(fnvalvar.Value)
	}
	status, _ := constant.Int64Val(gvar.toFieldNamed("atomicstatus").Value)
	f, l, fn := gvar.dbp.goSymTable.PCToLine(uint64(pc))
	g := &G{
		ID:         int(id),
		GoPC:       uint64(gopc),
		PC:         uint64(pc),
		SP:         uint64(sp),
		WaitReason: waitReason,
		DeferPC:    uint64(deferPC),
		Status:     uint64(status),
		CurrentLoc: Location{PC: uint64(pc), File: f, Line: l, Fn: fn},
		dbp:        gvar.dbp,
	}
	return g, nil
}

func TestNextConcurrent(t *testing.T) {
	testcases := []nextTest{
		{8, 9},
		{9, 10},
		{10, 11},
	}
	withTestProcess("parallel_next", t, func(p *Process, fixture protest.Fixture) {
		bp, err := setFunctionBreakpoint(p, "main.sayhi")
		assertNoError(err, t, "SetBreakpoint")
		assertNoError(p.Continue(), t, "Continue")
		f, ln := currentLineNumber(p, t)
		initV, err := evalVariable(p, "n")
		initVval, _ := constant.Int64Val(initV.Value)
		assertNoError(err, t, "EvalVariable")
		_, err = p.ClearBreakpoint(bp.Addr)
		assertNoError(err, t, "ClearBreakpoint()")
		for _, tc := range testcases {
			g, err := p.CurrentThread.GetG()
			assertNoError(err, t, "GetG()")
			if p.SelectedGoroutine.ID != g.ID {
				t.Fatalf("SelectedGoroutine not CurrentThread's goroutine: %d %d", g.ID, p.SelectedGoroutine.ID)
			}
			if ln != tc.begin {
				t.Fatalf("Program not stopped at correct spot expected %d was %s:%d", tc.begin, filepath.Base(f), ln)
			}
			assertNoError(p.Next(), t, "Next() returned an error")
			f, ln = currentLineNumber(p, t)
			if ln != tc.end {
				t.Fatalf("Program did not continue to correct next location expected %d was %s:%d", tc.end, filepath.Base(f), ln)
			}
			v, err := evalVariable(p, "n")
			assertNoError(err, t, "EvalVariable")
			vval, _ := constant.Int64Val(v.Value)
			if vval != initVval {
				t.Fatal("Did not end up on same goroutine")
			}
		}
	})
}

// Int64 returns the numeric value of this constant truncated to fit
// a signed 64-bit integer.
//
func (c *Const) Int64() int64 {
	switch x := c.Value; x.Kind() {
	case exact.Int:
		if i, ok := exact.Int64Val(x); ok {
			return i
		}
		return 0
	case exact.Float:
		f, _ := exact.Float64Val(x)
		return int64(f)
	}
	panic(fmt.Sprintf("unexpected constant value: %T", c.Value))
}

func (g *ObjcGen) genConstM(o *types.Const) {
	if _, ok := o.Type().(*types.Basic); !ok {
		g.Printf("// skipped const %s with unsupported type: %T\n\n", o.Name(), o)
		return
	}
	cName := fmt.Sprintf("%s%s", g.namePrefix, o.Name())
	objcType := g.objcType(o.Type())

	switch b := o.Type().(*types.Basic); b.Kind() {
	case types.Bool, types.UntypedBool:
		v := "NO"
		if constant.BoolVal(o.Val()) {
			v = "YES"
		}
		g.Printf("const BOOL %s = %s;\n", cName, v)

	case types.String, types.UntypedString:
		g.Printf("NSString* const %s = @%s;\n", cName, constExactString(o))

	case types.Int, types.Int8, types.Int16, types.Int32:
		g.Printf("const %s %s = %s;\n", objcType, cName, o.Val())

	case types.Int64, types.UntypedInt:
		i, exact := constant.Int64Val(o.Val())
		if !exact {
			g.errorf("const value %s for %s cannot be represented as %s", o.Val(), o.Name(), objcType)
			return
		}
		if i == math.MinInt64 {
			// -9223372036854775808LL does not work because 922337203685477508 is
			// larger than max int64.
			g.Printf("const int64_t %s = %dLL-1;\n", cName, i+1)
		} else {
			g.Printf("const int64_t %s = %dLL;\n", cName, i)
		}

	case types.Float32, types.Float64, types.UntypedFloat:
		f, _ := constant.Float64Val(o.Val())
		if math.IsInf(f, 0) || math.Abs(f) > math.MaxFloat64 {
			g.errorf("const value %s for %s cannot be represented as double", o.Val(), o.Name())
			return
		}
		g.Printf("const %s %s = %g;\n", objcType, cName, f)

	default:
		g.errorf("unsupported const type %s for %s", b, o.Name())
	}
}

func (v *Variable) asInt() (int64, error) {
	if v.DwarfType == nil {
		if v.Value.Kind() != constant.Int {
			return 0, fmt.Errorf("can not convert constant %s to int", v.Value)
		}
	} else {
		v.loadValue()
		if v.Unreadable != nil {
			return 0, v.Unreadable
		}
		if _, ok := v.DwarfType.(*dwarf.IntType); !ok {
			return 0, fmt.Errorf("can not convert value of type %s to int", v.DwarfType.String())
		}
	}
	n, _ := constant.Int64Val(v.Value)
	return n, nil
}

// checkLongShift checks if shift or shift-assign operations shift by more than
// the length of the underlying variable.
func checkLongShift(f *File, node ast.Node, x, y ast.Expr) {
	if f.pkg.types[x].Value != nil {
		// Ignore shifts of constants.
		// These are frequently used for bit-twiddling tricks
		// like ^uint(0) >> 63 for 32/64 bit detection and compatibility.
		return
	}
	v := f.pkg.types[y].Value
	if v == nil {
		return
	}
	amt, ok := constant.Int64Val(v)
	if !ok {
		return
	}
	t := f.pkg.types[x].Type
	if t == nil {
		return
	}
	b, ok := t.Underlying().(*types.Basic)
	if !ok {
		return
	}
	var size int64
	var msg string
	switch b.Kind() {
	case types.Uint8, types.Int8:
		size = 8
	case types.Uint16, types.Int16:
		size = 16
	case types.Uint32, types.Int32:
		size = 32
	case types.Uint64, types.Int64:
		size = 64
	case types.Int, types.Uint, types.Uintptr:
		// These types may be as small as 32 bits, but no smaller.
		size = 32
		msg = "might be "
	default:
		return
	}
	if amt >= size {
		ident := f.gofmt(x)
		f.Badf(node.Pos(), "%s %stoo small for shift of %d", ident, msg, amt)
	}
}

func (p *exporter) value(x constant.Value) {
	if trace {
		p.tracef("= ")
	}

	switch x.Kind() {
	case constant.Bool:
		tag := falseTag
		if constant.BoolVal(x) {
			tag = trueTag
		}
		p.tag(tag)

	case constant.Int:
		if v, exact := constant.Int64Val(x); exact {
			// common case: x fits into an int64 - use compact encoding
			p.tag(int64Tag)
			p.int64(v)
			return
		}
		// uncommon case: large x - use float encoding
		// (powers of 2 will be encoded efficiently with exponent)
		p.tag(floatTag)
		p.float(constant.ToFloat(x))

	case constant.Float:
		p.tag(floatTag)
		p.float(x)

	case constant.Complex:
		p.tag(complexTag)
		p.float(constant.Real(x))
		p.float(constant.Imag(x))

	case constant.String:
		p.tag(stringTag)
		p.string(constant.StringVal(x))

	case constant.Unknown:
		// package contains type errors
		p.tag(unknownTag)

	default:
		log.Fatalf("gcimporter: unexpected value %v (%T)", x, x)
	}
}

func TestCondBreakpointError(t *testing.T) {
	withTestProcess("parallel_next", t, func(p *Process, fixture protest.Fixture) {
		addr, _, err := p.goSymTable.LineToPC(fixture.Source, 9)
		assertNoError(err, t, "LineToPC")
		bp, err := p.SetBreakpoint(addr)
		assertNoError(err, t, "SetBreakpoint()")
		bp.Cond = &ast.BinaryExpr{
			Op: token.EQL,
			X:  &ast.Ident{Name: "nonexistentvariable"},
			Y:  &ast.BasicLit{Kind: token.INT, Value: "7"},
		}

		err = p.Continue()
		if err == nil {
			t.Fatalf("No error on first Continue()")
		}

		if err.Error() != "error evaluating expression: could not find symbol value for nonexistentvariable" && err.Error() != "multiple errors evaluating conditions" {
			t.Fatalf("Unexpected error on first Continue(): %v", err)
		}

		bp.Cond = &ast.BinaryExpr{
			Op: token.EQL,
			X:  &ast.Ident{Name: "n"},
			Y:  &ast.BasicLit{Kind: token.INT, Value: "7"},
		}

		err = p.Continue()
		if err != nil {
			if _, exited := err.(ProcessExitedError); !exited {
				t.Fatalf("Unexpected error on second Continue(): %v", err)
			}
		} else {
			nvar, err := evalVariable(p, "n")
			assertNoError(err, t, "EvalVariable()")

			n, _ := constant.Int64Val(nvar.Value)
			if n != 7 {
				t.Fatalf("Stoppend on wrong goroutine %d\n", n)
			}
		}
	})
}