bool CheckArity(Obj[] args, int numArgs, int stackStart)
{
ObjFn fn = args[stackStart] as ObjFn;
ObjClosure c = args[stackStart] as ObjClosure;
if (c != null)
{
fn = c.Function;
}
if (fn == null)
{
Fiber.Error = Obj.MakeString("Receiver must be a function or closure.");
return(false);
}
if (numArgs - 1 < fn.Arity)
{
Fiber.Error = Obj.MakeString("Function expects more arguments.");
return(false);
}
return(true);
}
// The main bytecode interpreter loop. This is where the magic happens. It is
// also, as you can imagine, highly performance critical. Returns `true` if the
// fiber completed without error.
private bool RunInterpreter()
{
/* Load Frame */
CallFrame frame = Fiber.Frames[Fiber.NumFrames - 1];
int ip = frame.Ip;
int stackStart = frame.StackStart;
Obj[] stack = Fiber.Stack;
ObjFn fn = frame.Fn as ObjFn ?? ((ObjClosure)frame.Fn).Function;
byte[] bytecode = fn.Bytecode;
while (true)
{
Instruction instruction = (Instruction)bytecode[ip++];
int index;
switch (instruction)
{
case Instruction.LOAD_LOCAL_0:
case Instruction.LOAD_LOCAL_1:
case Instruction.LOAD_LOCAL_2:
case Instruction.LOAD_LOCAL_3:
case Instruction.LOAD_LOCAL_4:
case Instruction.LOAD_LOCAL_5:
case Instruction.LOAD_LOCAL_6:
case Instruction.LOAD_LOCAL_7:
case Instruction.LOAD_LOCAL_8:
{
index = stackStart + instruction - Instruction.LOAD_LOCAL_0;
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = stack[index];
break;
}
case Instruction.LOAD_LOCAL:
{
index = stackStart + bytecode[ip++];
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = stack[index];
break;
}
case Instruction.LOAD_FIELD_THIS:
{
byte field = bytecode[ip++];
ObjInstance instance = (ObjInstance)stack[stackStart];
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = instance.Fields[field];
break;
}
case Instruction.POP:
{
Fiber.StackTop--;
break;
}
case Instruction.DUP:
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop] = stack[Fiber.StackTop - 1];
Fiber.StackTop++;
break;
}
case Instruction.NULL:
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = Obj.Null;
break;
}
case Instruction.FALSE:
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = Obj.False;
break;
}
case Instruction.TRUE:
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = Obj.True;
break;
}
case Instruction.CALL_0:
case Instruction.CALL_1:
case Instruction.CALL_2:
case Instruction.CALL_3:
case Instruction.CALL_4:
case Instruction.CALL_5:
case Instruction.CALL_6:
case Instruction.CALL_7:
case Instruction.CALL_8:
case Instruction.CALL_9:
case Instruction.CALL_10:
case Instruction.CALL_11:
case Instruction.CALL_12:
case Instruction.CALL_13:
case Instruction.CALL_14:
case Instruction.CALL_15:
case Instruction.CALL_16:
// Handle Super calls
case Instruction.SUPER_0:
case Instruction.SUPER_1:
case Instruction.SUPER_2:
case Instruction.SUPER_3:
case Instruction.SUPER_4:
case Instruction.SUPER_5:
case Instruction.SUPER_6:
case Instruction.SUPER_7:
case Instruction.SUPER_8:
case Instruction.SUPER_9:
case Instruction.SUPER_10:
case Instruction.SUPER_11:
case Instruction.SUPER_12:
case Instruction.SUPER_13:
case Instruction.SUPER_14:
case Instruction.SUPER_15:
case Instruction.SUPER_16:
{
int numArgs = instruction - (instruction >= Instruction.SUPER_0 ? Instruction.SUPER_0 : Instruction.CALL_0) + 1;
int symbol = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
// The receiver is the first argument.
int argStart = Fiber.StackTop - numArgs;
Obj receiver = stack[argStart];
ObjClass classObj;
if (instruction < Instruction.SUPER_0)
{
if (receiver.Type == ObjType.Obj)
{
classObj = receiver.ClassObj;
}
else if (receiver.Type == ObjType.Num)
{
classObj = NumClass;
}
else if (receiver == Obj.True || receiver == Obj.False)
{
classObj = BoolClass;
}
else
{
classObj = NullClass;
}
}
else
{
// The superclass is stored in a constant.
classObj = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]] as ObjClass;
ip += 2;
}
// If the class's method table doesn't include the symbol, bail.
Method method = symbol < classObj.Methods.Length ? classObj.Methods[symbol] : null;
if (method == null)
{
/* Method not found */
frame.Ip = ip;
MethodNotFound(this, classObj, symbol);
if (!HandleRuntimeError())
{
return(false);
}
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
if (method.MType == MethodType.Primitive)
{
// After calling this, the result will be in the first arg slot.
if (method.Primitive(this, stack, argStart))
{
Fiber.StackTop = argStart + 1;
}
else
{
frame.Ip = ip;
if (Fiber.Error != null && Fiber.Error != Obj.Null)
{
if (!HandleRuntimeError())
{
return(false);
}
}
else
{
// If we don't have a fiber to switch to, stop interpreting.
if (stack[argStart] == Obj.Null)
{
return(true);
}
Fiber = stack[argStart] as ObjFiber;
if (Fiber == null)
{
return(false);
}
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
}
break;
}
frame.Ip = ip;
if (method.MType == MethodType.Block)
{
receiver = method.Obj;
}
else if (!CheckArity(stack, numArgs, argStart))
{
if (!HandleRuntimeError())
{
return(false);
}
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
Fiber.Frames.Add(frame = new CallFrame {
Fn = receiver, StackStart = argStart, Ip = 0
});
Fiber.NumFrames++;
/* Load Frame */
ip = 0;
stackStart = argStart;
fn = (receiver as ObjFn) ?? (receiver as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
case Instruction.STORE_LOCAL:
{
index = stackStart + bytecode[ip++];
stack[index] = stack[Fiber.StackTop - 1];
break;
}
case Instruction.CONSTANT:
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
break;
}
case Instruction.LOAD_UPVALUE:
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = ((ObjClosure)frame.Fn).Upvalues[bytecode[ip++]].Container;
break;
}
case Instruction.STORE_UPVALUE:
{
ObjUpvalue[] upvalues = ((ObjClosure)frame.Fn).Upvalues;
upvalues[bytecode[ip++]].Container = stack[Fiber.StackTop - 1];
break;
}
case Instruction.LOAD_MODULE_VAR:
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = fn.Module.Variables[(bytecode[ip] << 8) + bytecode[ip + 1]].Container;
ip += 2;
break;
}
case Instruction.STORE_MODULE_VAR:
{
fn.Module.Variables[(bytecode[ip] << 8) + bytecode[ip + 1]].Container = stack[Fiber.StackTop - 1];
ip += 2;
break;
}
case Instruction.STORE_FIELD_THIS:
{
byte field = bytecode[ip++];
ObjInstance instance = (ObjInstance)stack[stackStart];
instance.Fields[field] = stack[Fiber.StackTop - 1];
break;
}
case Instruction.LOAD_FIELD:
{
byte field = bytecode[ip++];
ObjInstance instance = (ObjInstance)stack[--Fiber.StackTop];
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = instance.Fields[field];
break;
}
case Instruction.STORE_FIELD:
{
byte field = bytecode[ip++];
ObjInstance instance = (ObjInstance)stack[--Fiber.StackTop];
instance.Fields[field] = stack[Fiber.StackTop - 1];
break;
}
case Instruction.JUMP:
{
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += offset + 2;
break;
}
case Instruction.LOOP:
{
// Jump back to the top of the loop.
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
ip -= offset;
break;
}
case Instruction.JUMP_IF:
{
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
Obj condition = stack[--Fiber.StackTop];
if (condition == Obj.False || condition == Obj.Null)
{
ip += offset;
}
break;
}
case Instruction.AND:
case Instruction.OR:
{
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
Obj condition = stack[Fiber.StackTop - 1];
if ((condition == Obj.Null || condition == Obj.False) ^ instruction == Instruction.OR)
{
ip += offset;
}
else
{
Fiber.StackTop--;
}
break;
}
case Instruction.CLOSE_UPVALUE:
{
Fiber.CloseUpvalue();
Fiber.StackTop--;
break;
}
case Instruction.RETURN:
{
Fiber.Frames.RemoveAt(--Fiber.NumFrames);
Obj result = stack[--Fiber.StackTop];
// Close any upvalues still in scope.
if (Fiber.StackTop > stackStart)
{
while (Fiber.OpenUpvalues != null && Fiber.OpenUpvalues.Index >= stackStart)
{
Fiber.CloseUpvalue();
}
}
// If the fiber is complete, end it.
if (Fiber.NumFrames == 0)
{
// If this is the main fiber, we're done.
if (Fiber.Caller == null)
{
return(true);
}
// We have a calling fiber to resume.
Fiber = Fiber.Caller;
stack = Fiber.Stack;
// Store the result in the resuming fiber.
stack[Fiber.StackTop - 1] = result;
}
else
{
// Discard the stack slots for the call frame (leaving one slot for the result).
Fiber.StackTop = stackStart + 1;
// Store the result of the block in the first slot, which is where the
// caller expects it.
stack[stackStart] = result;
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
fn = frame.Fn as ObjFn ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
case Instruction.CLOSURE:
{
ObjFn prototype = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]] as ObjFn;
ip += 2;
// Create the closure and push it on the stack before creating upvalues
// so that it doesn't get collected.
ObjClosure closure = new ObjClosure(prototype);
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = closure;
// Capture upvalues.
for (int i = 0; i < prototype.NumUpvalues; i++)
{
byte isLocal = bytecode[ip++];
index = bytecode[ip++];
if (isLocal > 0)
{
// Make an new upvalue to close over the parent's local variable.
closure.Upvalues[i] = Fiber.CaptureUpvalue(stackStart + index);
}
else
{
// Use the same upvalue as the current call frame.
closure.Upvalues[i] = ((ObjClosure)frame.Fn).Upvalues[index];
}
}
break;
}
case Instruction.CLASS:
{
Obj name = stack[Fiber.StackTop - 2];
ObjClass superclass = stack[Fiber.StackTop - 1] as ObjClass;
Obj error = ValidateSuperclass(name, stack[Fiber.StackTop - 1]);
if (error != null)
{
Fiber.Error = error;
frame.Ip = ip;
if (!HandleRuntimeError())
{
return(false);
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
int numFields = bytecode[ip++];
Obj classObj = new ObjClass(superclass, numFields, name as ObjString);
// Don't pop the superclass and name off the stack until the subclass is
// done being created, to make sure it doesn't get collected.
Fiber.StackTop -= 2;
// Now that we know the total number of fields, make sure we don't overflow.
if (superclass.NumFields + numFields <= Compiler.MaxFields)
{
stack[Fiber.StackTop++] = classObj;
break;
}
// Overflow handling
frame.Ip = ip;
Fiber.Error = Obj.MakeString(string.Format("Class '{0}' may not have more than 255 fields, including inherited ones.", name));
if (!HandleRuntimeError())
{
return(false);
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
case Instruction.METHOD_INSTANCE:
case Instruction.METHOD_STATIC:
{
int symbol = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
ObjClass classObj = stack[Fiber.StackTop - 1] as ObjClass;
Obj method = stack[Fiber.StackTop - 2];
bool isStatic = instruction == Instruction.METHOD_STATIC;
if (!BindMethod(isStatic, symbol, classObj, method))
{
frame.Ip = ip;
Fiber.Error = Obj.MakeString("Error while binding method");
if (!HandleRuntimeError())
{
return(false);
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
Fiber.StackTop -= 2;
break;
}
case Instruction.LOAD_MODULE:
{
Obj name = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
Obj result = ImportModule(name);
// If it returned a string, it was an error message.
if ((result is ObjString))
{
frame.Ip = ip;
Fiber.Error = result;
if (!HandleRuntimeError())
{
return(false);
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
// Make a slot that the module's fiber can use to store its result in.
// It ends up getting discarded, but CODE_RETURN expects to be able to
// place a value there.
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = Obj.Null;
// If it returned a fiber to execute the module body, switch to it.
if (result is ObjFiber)
{
// Return to this module when that one is done.
(result as ObjFiber).Caller = Fiber;
frame.Ip = ip;
Fiber = (result as ObjFiber);
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
}
break;
}
case Instruction.IMPORT_VARIABLE:
{
Obj module = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
Obj variable = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
Obj result;
if (ImportVariable(module, variable, out result))
{
if (Fiber.StackTop >= Fiber.Capacity)
{
stack = Fiber.IncreaseStack();
}
stack[Fiber.StackTop++] = result;
}
else
{
frame.Ip = ip;
Fiber.Error = result;
if (!HandleRuntimeError())
{
return(false);
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
}
break;
}
case Instruction.CONSTRUCT:
{
int stackPosition = Fiber.StackTop - 1 + (Instruction.CALL_0 - (Instruction)bytecode[ip]);
ObjClass v = stack[stackPosition] as ObjClass;
if (v == null)
{
Fiber.Error = Obj.MakeString("'this' should be a class.");
if (!HandleRuntimeError())
{
return(false);
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
stack[stackPosition] = new ObjInstance(v);
}
break;
case Instruction.FOREIGN_CLASS:
// Not yet implemented
break;
case Instruction.FOREIGN_CONSTRUCT:
// Not yet implemented
break;
case Instruction.END:
// A CODE_END should always be preceded by a CODE_RETURN. If we get here,
// the compiler generated wrong code.
return(false);
}
}
// We should only exit this function from an explicit return from CODE_RETURN
// or a runtime error.
}
// The main bytecode interpreter loop. This is where the magic happens. It is
// also, as you can imagine, highly performance critical. Returns `true` if the
// fiber completed without error.
private bool RunInterpreter()
{
Instruction instruction;
int index;
/* Load Frame */
CallFrame frame = Fiber.Frames[Fiber.NumFrames - 1];
int ip = frame.Ip;
int stackStart = frame.StackStart;
Obj[] stack = Fiber.Stack;
ObjFn fn = frame.Fn as ObjFn ?? ((ObjClosure)frame.Fn).Function;
byte[] bytecode = fn.Bytecode;
while (true)
{
switch (instruction = (Instruction)bytecode[ip++])
{
case Instruction.LoadLocal0:
case Instruction.LoadLocal1:
case Instruction.LoadLocal2:
case Instruction.LoadLocal3:
case Instruction.LoadLocal4:
case Instruction.LoadLocal5:
case Instruction.LoadLocal6:
case Instruction.LoadLocal7:
case Instruction.LoadLocal8:
index = stackStart + (int)instruction; // LOAD_LOCAL_0 has code 0
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = stack[index];
break;
case Instruction.LoadLocal:
index = stackStart + bytecode[ip++];
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = stack[index];
break;
case Instruction.LoadFieldThis:
{
byte field = bytecode[ip++];
Obj receiver = stack[stackStart];
ObjInstance instance = receiver as ObjInstance;
if (Fiber.StackTop >= Fiber.Capacity)
Fiber.IncreaseStack();
stack[Fiber.StackTop++] = instance.Fields[field];
break;
}
case Instruction.Pop:
Fiber.StackTop--;
break;
case Instruction.Dup:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop] = stack[Fiber.StackTop - 1];
Fiber.StackTop++;
break;
case Instruction.Null:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = Obj.Null;
break;
case Instruction.False:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = Obj.False;
break;
case Instruction.True:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = Obj.True;
break;
case Instruction.Zero:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = Obj.Zero;
break;
case Instruction.One:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = Obj.One;
break;
case Instruction.Call0:
case Instruction.Call1:
case Instruction.Call2:
case Instruction.Call3:
case Instruction.Call4:
case Instruction.Call5:
case Instruction.Call6:
case Instruction.Call7:
case Instruction.Call8:
case Instruction.Call9:
case Instruction.Call10:
case Instruction.Call11:
case Instruction.Call12:
case Instruction.Call13:
case Instruction.Call14:
case Instruction.Call15:
case Instruction.Call16:
// Handle Super calls
case Instruction.Super0:
case Instruction.Super1:
case Instruction.Super2:
case Instruction.Super3:
case Instruction.Super4:
case Instruction.Super5:
case Instruction.Super6:
case Instruction.Super7:
case Instruction.Super8:
case Instruction.Super9:
case Instruction.Super10:
case Instruction.Super11:
case Instruction.Super12:
case Instruction.Super13:
case Instruction.Super14:
case Instruction.Super15:
case Instruction.Super16:
{
int numArgs = instruction - (instruction >= Instruction.Super0 ? Instruction.Super0 : Instruction.Call0) + 1;
int symbol = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
// The receiver is the first argument.
int argStart = Fiber.StackTop - numArgs;
Obj receiver = stack[argStart];
ObjClass classObj;
if (instruction < Instruction.Super0)
{
if (receiver.Type == ObjType.Obj)
classObj = receiver.ClassObj;
else if (receiver.Type == ObjType.Num)
classObj = NumClass;
else if (receiver == Obj.True || receiver == Obj.False)
classObj = BoolClass;
else
classObj = NullClass;
}
else
{
// The superclass is stored in a constant.
classObj = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]] as ObjClass;
ip += 2;
}
// If the class's method table doesn't include the symbol, bail.
Method method = symbol < classObj.Methods.Length ? classObj.Methods[symbol] : null;
if (method == null)
{
/* Method not found */
frame.Ip = ip;
MethodNotFound(this, classObj, symbol);
if (!HandleRuntimeError())
return false;
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
if (method.MType == MethodType.Primitive)
{
// After calling this, the result will be in the first arg slot.
if (method.Primitive(this, stack, argStart))
{
Fiber.StackTop = argStart + 1;
}
else
{
frame.Ip = ip;
if (Fiber.Error != null && Fiber.Error != Obj.Null)
{
if (!HandleRuntimeError())
return false;
}
else
{
// If we don't have a fiber to switch to, stop interpreting.
if (stack[argStart] == Obj.Null)
return true;
Fiber = stack[argStart] as ObjFiber;
if (Fiber == null)
return false;
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
}
break;
}
frame.Ip = ip;
if (method.MType == MethodType.Block)
{
receiver = method.Obj;
}
else if (!CheckArity(stack, numArgs, argStart))
{
if (!HandleRuntimeError())
return false;
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
Fiber.Frames.Add(frame = new CallFrame { Fn = receiver, StackStart = argStart, Ip = 0 });
Fiber.NumFrames++;
/* Load Frame */
ip = 0;
stackStart = argStart;
fn = (receiver as ObjFn) ?? (receiver as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
case Instruction.StoreLocal:
index = stackStart + bytecode[ip++];
stack[index] = stack[Fiber.StackTop - 1];
break;
case Instruction.SmallConstant:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = fn.Constants[bytecode[ip]];
ip += 1;
break;
case Instruction.Constant:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
break;
case Instruction.LoadUpvalue:
{
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = ((ObjClosure)frame.Fn).Upvalues[bytecode[ip++]].Container;
break;
}
case Instruction.StoreUpvalue:
{
ObjUpvalue[] upvalues = ((ObjClosure)frame.Fn).Upvalues;
upvalues[bytecode[ip++]].Container = stack[Fiber.StackTop - 1];
break;
}
case Instruction.LoadModuleVar:
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = fn.Module.Variables[(bytecode[ip] << 8) + bytecode[ip + 1]].Container;
ip += 2;
break;
case Instruction.StoreModuleVar:
fn.Module.Variables[(bytecode[ip] << 8) + bytecode[ip + 1]].Container = stack[Fiber.StackTop - 1];
ip += 2;
break;
case Instruction.StoreFieldThis:
{
byte field = bytecode[ip++];
Obj receiver = stack[stackStart];
ObjInstance instance = receiver as ObjInstance;
instance.Fields[field] = stack[Fiber.StackTop - 1];
break;
}
case Instruction.LoadField:
{
byte field = bytecode[ip++];
Obj receiver = stack[--Fiber.StackTop];
ObjInstance instance = receiver as ObjInstance;
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = instance.Fields[field];
break;
}
case Instruction.StoreField:
{
byte field = bytecode[ip++];
Obj receiver = stack[--Fiber.StackTop];
ObjInstance instance = receiver as ObjInstance;
instance.Fields[field] = stack[Fiber.StackTop - 1];
break;
}
case Instruction.Jump:
{
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += offset + 2;
break;
}
case Instruction.Loop:
{
// Jump back to the top of the loop.
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
ip -= offset;
break;
}
case Instruction.JumpIf:
{
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
Obj condition = stack[--Fiber.StackTop];
if (condition == Obj.False || condition == Obj.Null) ip += offset;
break;
}
case Instruction.And:
{
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
ObjType condition = stack[Fiber.StackTop - 1].Type;
switch (condition)
{
case ObjType.Null:
case ObjType.False:
ip += offset;
break;
default:
Fiber.StackTop--;
break;
}
break;
}
case Instruction.Or:
{
int offset = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
Obj condition = stack[Fiber.StackTop - 1];
switch (condition.Type)
{
case ObjType.Null:
case ObjType.False:
Fiber.StackTop--;
break;
default:
ip += offset;
break;
}
break;
}
case Instruction.CloseUpvalue:
Fiber.CloseUpvalue();
Fiber.StackTop--;
break;
case Instruction.Return:
{
Fiber.Frames.RemoveAt(--Fiber.NumFrames);
Obj result = stack[--Fiber.StackTop];
// Close any upvalues still in scope.
if (Fiber.StackTop > stackStart)
{
Obj first = stack[stackStart];
while (Fiber.OpenUpvalues != null &&
Fiber.OpenUpvalues.Container != first)
{
Fiber.CloseUpvalue();
}
Fiber.CloseUpvalue();
}
// If the fiber is complete, end it.
if (Fiber.NumFrames == 0)
{
// If this is the main fiber, we're done.
if (Fiber.Caller == null) return true;
// We have a calling fiber to resume.
Fiber = Fiber.Caller;
stack = Fiber.Stack;
// Store the result in the resuming fiber.
stack[Fiber.StackTop - 1] = result;
}
else
{
// Discard the stack slots for the call frame (leaving one slot for the result).
Fiber.StackTop = stackStart + 1;
// Store the result of the block in the first slot, which is where the
// caller expects it.
stack[Fiber.StackTop - 1] = result;
}
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
fn = frame.Fn as ObjFn ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
case Instruction.Closure:
{
ObjFn prototype = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]] as ObjFn;
ip += 2;
// Create the closure and push it on the stack before creating upvalues
// so that it doesn't get collected.
ObjClosure closure = new ObjClosure(prototype);
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = closure;
// Capture upvalues.
for (int i = 0; i < prototype.NumUpvalues; i++)
{
byte isLocal = bytecode[ip++];
index = bytecode[ip++];
if (isLocal > 0)
{
// Make an new upvalue to close over the parent's local variable.
closure.Upvalues[i] = Fiber.CaptureUpvalue(stackStart + index);
}
else
{
// Use the same upvalue as the current call frame.
closure.Upvalues[i] = ((ObjClosure)frame.Fn).Upvalues[index];
}
}
break;
}
case Instruction.Class:
{
Obj name = stack[Fiber.StackTop - 2];
ObjClass superclass = ObjectClass;
// Use implicit Object superclass if none given.
if (stack[Fiber.StackTop - 1] != Obj.Null)
{
Fiber.Error = ValidateSuperclass(name, stack[Fiber.StackTop - 1]);
if (Fiber.Error != null)
{
frame.Ip = ip;
if (!HandleRuntimeError())
return false;
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
superclass = stack[Fiber.StackTop - 1] as ObjClass;
}
int numFields = bytecode[ip++];
Obj classObj = new ObjClass(superclass, numFields, name as ObjString);
// Don't pop the superclass and name off the stack until the subclass is
// done being created, to make sure it doesn't get collected.
Fiber.StackTop -= 2;
// Now that we know the total number of fields, make sure we don't overflow.
if (superclass.NumFields + numFields > Compiler.MaxFields)
{
frame.Ip = ip;
Fiber.Error = Obj.MakeString(string.Format("Class '{0}' may not have more than 255 fields, including inherited ones.", name));
if (!HandleRuntimeError())
return false;
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = classObj;
break;
}
case Instruction.MethodInstance:
case Instruction.MethodStatic:
{
int symbol = (bytecode[ip] << 8) + bytecode[ip + 1];
ip += 2;
ObjClass classObj = stack[Fiber.StackTop - 1] as ObjClass;
Obj method = stack[Fiber.StackTop - 2];
bool isStatic = instruction != Instruction.MethodInstance;
Fiber.Error = BindMethod(isStatic, symbol, classObj, method);
if (Fiber.Error != null)
{
frame.Ip = ip;
if (!HandleRuntimeError())
return false;
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
Fiber.StackTop -= 2;
break;
}
case Instruction.LoadModule:
{
Obj name = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
Obj result = ImportModule(name);
// If it returned a string, it was an error message.
if ((result is ObjString))
{
frame.Ip = ip;
Fiber.Error = result;
if (!HandleRuntimeError())
return false;
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
break;
}
// Make a slot that the module's fiber can use to store its result in.
// It ends up getting discarded, but CODE_RETURN expects to be able to
// place a value there.
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = Obj.Null;
// If it returned a fiber to execute the module body, switch to it.
if (result is ObjFiber)
{
// Return to this module when that one is done.
(result as ObjFiber).Caller = Fiber;
frame.Ip = ip;
Fiber = (result as ObjFiber);
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
}
break;
}
case Instruction.ImportVariable:
{
Obj module = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
Obj variable = fn.Constants[(bytecode[ip] << 8) + bytecode[ip + 1]];
ip += 2;
Obj result;
if (ImportVariable(module, variable, out result))
{
if (Fiber.StackTop >= Fiber.Capacity)
stack = Fiber.IncreaseStack();
stack[Fiber.StackTop++] = result;
}
else
{
frame.Ip = ip;
Fiber.Error = result;
if (!HandleRuntimeError())
return false;
/* Load Frame */
frame = Fiber.Frames[Fiber.NumFrames - 1];
ip = frame.Ip;
stackStart = frame.StackStart;
stack = Fiber.Stack;
fn = (frame.Fn as ObjFn) ?? (frame.Fn as ObjClosure).Function;
bytecode = fn.Bytecode;
}
break;
}
case Instruction.End:
// A CODE_END should always be preceded by a CODE_RETURN. If we get here,
// the compiler generated wrong code.
return false;
}
}
// We should only exit this function from an explicit return from CODE_RETURN
// or a runtime error.
}
