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matterbridge/vendor/github.com/d5/tengo/v2/vm.go
2020-03-28 23:41:35 +01:00

884 lines
20 KiB
Go

package tengo
import (
"fmt"
"sync/atomic"
"github.com/d5/tengo/v2/parser"
"github.com/d5/tengo/v2/token"
)
// frame represents a function call frame.
type frame struct {
fn *CompiledFunction
freeVars []*ObjectPtr
ip int
basePointer int
}
// VM is a virtual machine that executes the bytecode compiled by Compiler.
type VM struct {
constants []Object
stack [StackSize]Object
sp int
globals []Object
fileSet *parser.SourceFileSet
frames [MaxFrames]frame
framesIndex int
curFrame *frame
curInsts []byte
ip int
aborting int64
maxAllocs int64
allocs int64
err error
}
// NewVM creates a VM.
func NewVM(
bytecode *Bytecode,
globals []Object,
maxAllocs int64,
) *VM {
if globals == nil {
globals = make([]Object, GlobalsSize)
}
v := &VM{
constants: bytecode.Constants,
sp: 0,
globals: globals,
fileSet: bytecode.FileSet,
framesIndex: 1,
ip: -1,
maxAllocs: maxAllocs,
}
v.frames[0].fn = bytecode.MainFunction
v.frames[0].ip = -1
v.curFrame = &v.frames[0]
v.curInsts = v.curFrame.fn.Instructions
return v
}
// Abort aborts the execution.
func (v *VM) Abort() {
atomic.StoreInt64(&v.aborting, 1)
}
// Run starts the execution.
func (v *VM) Run() (err error) {
// reset VM states
v.sp = 0
v.curFrame = &(v.frames[0])
v.curInsts = v.curFrame.fn.Instructions
v.framesIndex = 1
v.ip = -1
v.allocs = v.maxAllocs + 1
v.run()
atomic.StoreInt64(&v.aborting, 0)
err = v.err
if err != nil {
filePos := v.fileSet.Position(
v.curFrame.fn.SourcePos(v.ip - 1))
err = fmt.Errorf("Runtime Error: %w\n\tat %s",
err, filePos)
for v.framesIndex > 1 {
v.framesIndex--
v.curFrame = &v.frames[v.framesIndex-1]
filePos = v.fileSet.Position(
v.curFrame.fn.SourcePos(v.curFrame.ip - 1))
err = fmt.Errorf("%w\n\tat %s", err, filePos)
}
return err
}
return nil
}
func (v *VM) run() {
for atomic.LoadInt64(&v.aborting) == 0 {
v.ip++
switch v.curInsts[v.ip] {
case parser.OpConstant:
v.ip += 2
cidx := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
v.stack[v.sp] = v.constants[cidx]
v.sp++
case parser.OpNull:
v.stack[v.sp] = UndefinedValue
v.sp++
case parser.OpBinaryOp:
v.ip++
right := v.stack[v.sp-1]
left := v.stack[v.sp-2]
tok := token.Token(v.curInsts[v.ip])
res, e := left.BinaryOp(tok, right)
if e != nil {
v.sp -= 2
if e == ErrInvalidOperator {
v.err = fmt.Errorf("invalid operation: %s %s %s",
left.TypeName(), tok.String(), right.TypeName())
return
}
v.err = e
return
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp-2] = res
v.sp--
case parser.OpEqual:
right := v.stack[v.sp-1]
left := v.stack[v.sp-2]
v.sp -= 2
if left.Equals(right) {
v.stack[v.sp] = TrueValue
} else {
v.stack[v.sp] = FalseValue
}
v.sp++
case parser.OpNotEqual:
right := v.stack[v.sp-1]
left := v.stack[v.sp-2]
v.sp -= 2
if left.Equals(right) {
v.stack[v.sp] = FalseValue
} else {
v.stack[v.sp] = TrueValue
}
v.sp++
case parser.OpPop:
v.sp--
case parser.OpTrue:
v.stack[v.sp] = TrueValue
v.sp++
case parser.OpFalse:
v.stack[v.sp] = FalseValue
v.sp++
case parser.OpLNot:
operand := v.stack[v.sp-1]
v.sp--
if operand.IsFalsy() {
v.stack[v.sp] = TrueValue
} else {
v.stack[v.sp] = FalseValue
}
v.sp++
case parser.OpBComplement:
operand := v.stack[v.sp-1]
v.sp--
switch x := operand.(type) {
case *Int:
var res Object = &Int{Value: ^x.Value}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = res
v.sp++
default:
v.err = fmt.Errorf("invalid operation: ^%s",
operand.TypeName())
return
}
case parser.OpMinus:
operand := v.stack[v.sp-1]
v.sp--
switch x := operand.(type) {
case *Int:
var res Object = &Int{Value: -x.Value}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = res
v.sp++
case *Float:
var res Object = &Float{Value: -x.Value}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = res
v.sp++
default:
v.err = fmt.Errorf("invalid operation: -%s",
operand.TypeName())
return
}
case parser.OpJumpFalsy:
v.ip += 2
v.sp--
if v.stack[v.sp].IsFalsy() {
pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
v.ip = pos - 1
}
case parser.OpAndJump:
v.ip += 2
if v.stack[v.sp-1].IsFalsy() {
pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
v.ip = pos - 1
} else {
v.sp--
}
case parser.OpOrJump:
v.ip += 2
if v.stack[v.sp-1].IsFalsy() {
v.sp--
} else {
pos := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
v.ip = pos - 1
}
case parser.OpJump:
pos := int(v.curInsts[v.ip+2]) | int(v.curInsts[v.ip+1])<<8
v.ip = pos - 1
case parser.OpSetGlobal:
v.ip += 2
v.sp--
globalIndex := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
v.globals[globalIndex] = v.stack[v.sp]
case parser.OpSetSelGlobal:
v.ip += 3
globalIndex := int(v.curInsts[v.ip-1]) | int(v.curInsts[v.ip-2])<<8
numSelectors := int(v.curInsts[v.ip])
// selectors and RHS value
selectors := make([]Object, numSelectors)
for i := 0; i < numSelectors; i++ {
selectors[i] = v.stack[v.sp-numSelectors+i]
}
val := v.stack[v.sp-numSelectors-1]
v.sp -= numSelectors + 1
e := indexAssign(v.globals[globalIndex], val, selectors)
if e != nil {
v.err = e
return
}
case parser.OpGetGlobal:
v.ip += 2
globalIndex := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
val := v.globals[globalIndex]
v.stack[v.sp] = val
v.sp++
case parser.OpArray:
v.ip += 2
numElements := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
var elements []Object
for i := v.sp - numElements; i < v.sp; i++ {
elements = append(elements, v.stack[i])
}
v.sp -= numElements
var arr Object = &Array{Value: elements}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = arr
v.sp++
case parser.OpMap:
v.ip += 2
numElements := int(v.curInsts[v.ip]) | int(v.curInsts[v.ip-1])<<8
kv := make(map[string]Object)
for i := v.sp - numElements; i < v.sp; i += 2 {
key := v.stack[i]
value := v.stack[i+1]
kv[key.(*String).Value] = value
}
v.sp -= numElements
var m Object = &Map{Value: kv}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = m
v.sp++
case parser.OpError:
value := v.stack[v.sp-1]
var e Object = &Error{
Value: value,
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp-1] = e
case parser.OpImmutable:
value := v.stack[v.sp-1]
switch value := value.(type) {
case *Array:
var immutableArray Object = &ImmutableArray{
Value: value.Value,
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp-1] = immutableArray
case *Map:
var immutableMap Object = &ImmutableMap{
Value: value.Value,
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp-1] = immutableMap
}
case parser.OpIndex:
index := v.stack[v.sp-1]
left := v.stack[v.sp-2]
v.sp -= 2
val, err := left.IndexGet(index)
if err != nil {
if err == ErrNotIndexable {
v.err = fmt.Errorf("not indexable: %s", index.TypeName())
return
}
if err == ErrInvalidIndexType {
v.err = fmt.Errorf("invalid index type: %s",
index.TypeName())
return
}
v.err = err
return
}
if val == nil {
val = UndefinedValue
}
v.stack[v.sp] = val
v.sp++
case parser.OpSliceIndex:
high := v.stack[v.sp-1]
low := v.stack[v.sp-2]
left := v.stack[v.sp-3]
v.sp -= 3
var lowIdx int64
if low != UndefinedValue {
if low, ok := low.(*Int); ok {
lowIdx = low.Value
} else {
v.err = fmt.Errorf("invalid slice index type: %s",
low.TypeName())
return
}
}
switch left := left.(type) {
case *Array:
numElements := int64(len(left.Value))
var highIdx int64
if high == UndefinedValue {
highIdx = numElements
} else if high, ok := high.(*Int); ok {
highIdx = high.Value
} else {
v.err = fmt.Errorf("invalid slice index type: %s",
high.TypeName())
return
}
if lowIdx > highIdx {
v.err = fmt.Errorf("invalid slice index: %d > %d",
lowIdx, highIdx)
return
}
if lowIdx < 0 {
lowIdx = 0
} else if lowIdx > numElements {
lowIdx = numElements
}
if highIdx < 0 {
highIdx = 0
} else if highIdx > numElements {
highIdx = numElements
}
var val Object = &Array{
Value: left.Value[lowIdx:highIdx],
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = val
v.sp++
case *ImmutableArray:
numElements := int64(len(left.Value))
var highIdx int64
if high == UndefinedValue {
highIdx = numElements
} else if high, ok := high.(*Int); ok {
highIdx = high.Value
} else {
v.err = fmt.Errorf("invalid slice index type: %s",
high.TypeName())
return
}
if lowIdx > highIdx {
v.err = fmt.Errorf("invalid slice index: %d > %d",
lowIdx, highIdx)
return
}
if lowIdx < 0 {
lowIdx = 0
} else if lowIdx > numElements {
lowIdx = numElements
}
if highIdx < 0 {
highIdx = 0
} else if highIdx > numElements {
highIdx = numElements
}
var val Object = &Array{
Value: left.Value[lowIdx:highIdx],
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = val
v.sp++
case *String:
numElements := int64(len(left.Value))
var highIdx int64
if high == UndefinedValue {
highIdx = numElements
} else if high, ok := high.(*Int); ok {
highIdx = high.Value
} else {
v.err = fmt.Errorf("invalid slice index type: %s",
high.TypeName())
return
}
if lowIdx > highIdx {
v.err = fmt.Errorf("invalid slice index: %d > %d",
lowIdx, highIdx)
return
}
if lowIdx < 0 {
lowIdx = 0
} else if lowIdx > numElements {
lowIdx = numElements
}
if highIdx < 0 {
highIdx = 0
} else if highIdx > numElements {
highIdx = numElements
}
var val Object = &String{
Value: left.Value[lowIdx:highIdx],
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = val
v.sp++
case *Bytes:
numElements := int64(len(left.Value))
var highIdx int64
if high == UndefinedValue {
highIdx = numElements
} else if high, ok := high.(*Int); ok {
highIdx = high.Value
} else {
v.err = fmt.Errorf("invalid slice index type: %s",
high.TypeName())
return
}
if lowIdx > highIdx {
v.err = fmt.Errorf("invalid slice index: %d > %d",
lowIdx, highIdx)
return
}
if lowIdx < 0 {
lowIdx = 0
} else if lowIdx > numElements {
lowIdx = numElements
}
if highIdx < 0 {
highIdx = 0
} else if highIdx > numElements {
highIdx = numElements
}
var val Object = &Bytes{
Value: left.Value[lowIdx:highIdx],
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = val
v.sp++
}
case parser.OpCall:
numArgs := int(v.curInsts[v.ip+1])
v.ip++
value := v.stack[v.sp-1-numArgs]
if !value.CanCall() {
v.err = fmt.Errorf("not callable: %s", value.TypeName())
return
}
if callee, ok := value.(*CompiledFunction); ok {
if callee.VarArgs {
// if the closure is variadic,
// roll up all variadic parameters into an array
realArgs := callee.NumParameters - 1
varArgs := numArgs - realArgs
if varArgs >= 0 {
numArgs = realArgs + 1
args := make([]Object, varArgs)
spStart := v.sp - varArgs
for i := spStart; i < v.sp; i++ {
args[i-spStart] = v.stack[i]
}
v.stack[spStart] = &Array{Value: args}
v.sp = spStart + 1
}
}
if numArgs != callee.NumParameters {
if callee.VarArgs {
v.err = fmt.Errorf(
"wrong number of arguments: want>=%d, got=%d",
callee.NumParameters-1, numArgs)
} else {
v.err = fmt.Errorf(
"wrong number of arguments: want=%d, got=%d",
callee.NumParameters, numArgs)
}
return
}
// test if it's tail-call
if callee == v.curFrame.fn { // recursion
nextOp := v.curInsts[v.ip+1]
if nextOp == parser.OpReturn ||
(nextOp == parser.OpPop &&
parser.OpReturn == v.curInsts[v.ip+2]) {
for p := 0; p < numArgs; p++ {
v.stack[v.curFrame.basePointer+p] =
v.stack[v.sp-numArgs+p]
}
v.sp -= numArgs + 1
v.ip = -1 // reset IP to beginning of the frame
continue
}
}
if v.framesIndex >= MaxFrames {
v.err = ErrStackOverflow
return
}
// update call frame
v.curFrame.ip = v.ip // store current ip before call
v.curFrame = &(v.frames[v.framesIndex])
v.curFrame.fn = callee
v.curFrame.freeVars = callee.Free
v.curFrame.basePointer = v.sp - numArgs
v.curInsts = callee.Instructions
v.ip = -1
v.framesIndex++
v.sp = v.sp - numArgs + callee.NumLocals
} else {
var args []Object
args = append(args, v.stack[v.sp-numArgs:v.sp]...)
ret, e := value.Call(args...)
v.sp -= numArgs + 1
// runtime error
if e != nil {
if e == ErrWrongNumArguments {
v.err = fmt.Errorf(
"wrong number of arguments in call to '%s'",
value.TypeName())
return
}
if e, ok := e.(ErrInvalidArgumentType); ok {
v.err = fmt.Errorf(
"invalid type for argument '%s' in call to '%s': "+
"expected %s, found %s",
e.Name, value.TypeName(), e.Expected, e.Found)
return
}
v.err = e
return
}
// nil return -> undefined
if ret == nil {
ret = UndefinedValue
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = ret
v.sp++
}
case parser.OpReturn:
v.ip++
var retVal Object
if int(v.curInsts[v.ip]) == 1 {
retVal = v.stack[v.sp-1]
} else {
retVal = UndefinedValue
}
//v.sp--
v.framesIndex--
v.curFrame = &v.frames[v.framesIndex-1]
v.curInsts = v.curFrame.fn.Instructions
v.ip = v.curFrame.ip
//v.sp = lastFrame.basePointer - 1
v.sp = v.frames[v.framesIndex].basePointer
// skip stack overflow check because (newSP) <= (oldSP)
v.stack[v.sp-1] = retVal
//v.sp++
case parser.OpDefineLocal:
v.ip++
localIndex := int(v.curInsts[v.ip])
sp := v.curFrame.basePointer + localIndex
// local variables can be mutated by other actions
// so always store the copy of popped value
val := v.stack[v.sp-1]
v.sp--
v.stack[sp] = val
case parser.OpSetLocal:
localIndex := int(v.curInsts[v.ip+1])
v.ip++
sp := v.curFrame.basePointer + localIndex
// update pointee of v.stack[sp] instead of replacing the pointer
// itself. this is needed because there can be free variables
// referencing the same local variables.
val := v.stack[v.sp-1]
v.sp--
if obj, ok := v.stack[sp].(*ObjectPtr); ok {
*obj.Value = val
val = obj
}
v.stack[sp] = val // also use a copy of popped value
case parser.OpSetSelLocal:
localIndex := int(v.curInsts[v.ip+1])
numSelectors := int(v.curInsts[v.ip+2])
v.ip += 2
// selectors and RHS value
selectors := make([]Object, numSelectors)
for i := 0; i < numSelectors; i++ {
selectors[i] = v.stack[v.sp-numSelectors+i]
}
val := v.stack[v.sp-numSelectors-1]
v.sp -= numSelectors + 1
dst := v.stack[v.curFrame.basePointer+localIndex]
if obj, ok := dst.(*ObjectPtr); ok {
dst = *obj.Value
}
if e := indexAssign(dst, val, selectors); e != nil {
v.err = e
return
}
case parser.OpGetLocal:
v.ip++
localIndex := int(v.curInsts[v.ip])
val := v.stack[v.curFrame.basePointer+localIndex]
if obj, ok := val.(*ObjectPtr); ok {
val = *obj.Value
}
v.stack[v.sp] = val
v.sp++
case parser.OpGetBuiltin:
v.ip++
builtinIndex := int(v.curInsts[v.ip])
v.stack[v.sp] = builtinFuncs[builtinIndex]
v.sp++
case parser.OpClosure:
v.ip += 3
constIndex := int(v.curInsts[v.ip-1]) | int(v.curInsts[v.ip-2])<<8
numFree := int(v.curInsts[v.ip])
fn, ok := v.constants[constIndex].(*CompiledFunction)
if !ok {
v.err = fmt.Errorf("not function: %s", fn.TypeName())
return
}
free := make([]*ObjectPtr, numFree)
for i := 0; i < numFree; i++ {
switch freeVar := (v.stack[v.sp-numFree+i]).(type) {
case *ObjectPtr:
free[i] = freeVar
default:
free[i] = &ObjectPtr{
Value: &v.stack[v.sp-numFree+i],
}
}
}
v.sp -= numFree
cl := &CompiledFunction{
Instructions: fn.Instructions,
NumLocals: fn.NumLocals,
NumParameters: fn.NumParameters,
VarArgs: fn.VarArgs,
Free: free,
}
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = cl
v.sp++
case parser.OpGetFreePtr:
v.ip++
freeIndex := int(v.curInsts[v.ip])
val := v.curFrame.freeVars[freeIndex]
v.stack[v.sp] = val
v.sp++
case parser.OpGetFree:
v.ip++
freeIndex := int(v.curInsts[v.ip])
val := *v.curFrame.freeVars[freeIndex].Value
v.stack[v.sp] = val
v.sp++
case parser.OpSetFree:
v.ip++
freeIndex := int(v.curInsts[v.ip])
*v.curFrame.freeVars[freeIndex].Value = v.stack[v.sp-1]
v.sp--
case parser.OpGetLocalPtr:
v.ip++
localIndex := int(v.curInsts[v.ip])
sp := v.curFrame.basePointer + localIndex
val := v.stack[sp]
var freeVar *ObjectPtr
if obj, ok := val.(*ObjectPtr); ok {
freeVar = obj
} else {
freeVar = &ObjectPtr{Value: &val}
v.stack[sp] = freeVar
}
v.stack[v.sp] = freeVar
v.sp++
case parser.OpSetSelFree:
v.ip += 2
freeIndex := int(v.curInsts[v.ip-1])
numSelectors := int(v.curInsts[v.ip])
// selectors and RHS value
selectors := make([]Object, numSelectors)
for i := 0; i < numSelectors; i++ {
selectors[i] = v.stack[v.sp-numSelectors+i]
}
val := v.stack[v.sp-numSelectors-1]
v.sp -= numSelectors + 1
e := indexAssign(*v.curFrame.freeVars[freeIndex].Value,
val, selectors)
if e != nil {
v.err = e
return
}
case parser.OpIteratorInit:
var iterator Object
dst := v.stack[v.sp-1]
v.sp--
if !dst.CanIterate() {
v.err = fmt.Errorf("not iterable: %s", dst.TypeName())
return
}
iterator = dst.Iterate()
v.allocs--
if v.allocs == 0 {
v.err = ErrObjectAllocLimit
return
}
v.stack[v.sp] = iterator
v.sp++
case parser.OpIteratorNext:
iterator := v.stack[v.sp-1]
v.sp--
hasMore := iterator.(Iterator).Next()
if hasMore {
v.stack[v.sp] = TrueValue
} else {
v.stack[v.sp] = FalseValue
}
v.sp++
case parser.OpIteratorKey:
iterator := v.stack[v.sp-1]
v.sp--
val := iterator.(Iterator).Key()
v.stack[v.sp] = val
v.sp++
case parser.OpIteratorValue:
iterator := v.stack[v.sp-1]
v.sp--
val := iterator.(Iterator).Value()
v.stack[v.sp] = val
v.sp++
case parser.OpSuspend:
return
default:
v.err = fmt.Errorf("unknown opcode: %d", v.curInsts[v.ip])
return
}
}
}
// IsStackEmpty tests if the stack is empty or not.
func (v *VM) IsStackEmpty() bool {
return v.sp == 0
}
func indexAssign(dst, src Object, selectors []Object) error {
numSel := len(selectors)
for sidx := numSel - 1; sidx > 0; sidx-- {
next, err := dst.IndexGet(selectors[sidx])
if err != nil {
if err == ErrNotIndexable {
return fmt.Errorf("not indexable: %s", dst.TypeName())
}
if err == ErrInvalidIndexType {
return fmt.Errorf("invalid index type: %s",
selectors[sidx].TypeName())
}
return err
}
dst = next
}
if err := dst.IndexSet(selectors[0], src); err != nil {
if err == ErrNotIndexAssignable {
return fmt.Errorf("not index-assignable: %s", dst.TypeName())
}
if err == ErrInvalidIndexValueType {
return fmt.Errorf("invaid index value type: %s", src.TypeName())
}
return err
}
return nil
}