godot/modules/gdscript/gdscript_function.cpp

/*************************************************************************/
/*  gdscript_function.cpp                                                */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2018 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2018 Godot Engine contributors (cf. AUTHORS.md)    */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/

#include "gdscript_function.h"

#include "gdscript.h"
#include "gdscript_functions.h"
#include "os/os.h"

Variant *GDScriptFunction::_get_variant(int p_address, GDScriptInstance *p_instance, GDScript *p_script, Variant &self, Variant *p_stack, String &r_error) const {

	int address = p_address & ADDR_MASK;

	//sequential table (jump table generated by compiler)
	switch ((p_address & ADDR_TYPE_MASK) >> ADDR_BITS) {

		case ADDR_TYPE_SELF: {
#ifdef DEBUG_ENABLED
			if (unlikely(!p_instance)) {
				r_error = "Cannot access self without instance.";
				return NULL;
			}
#endif
			return &self;
		} break;
		case ADDR_TYPE_CLASS: {

			return &p_script->_static_ref;
		} break;
		case ADDR_TYPE_MEMBER: {
#ifdef DEBUG_ENABLED
			if (unlikely(!p_instance)) {
				r_error = "Cannot access member without instance.";
				return NULL;
			}
#endif
			//member indexing is O(1)
			return &p_instance->members[address];
		} break;
		case ADDR_TYPE_CLASS_CONSTANT: {

			//todo change to index!
			GDScript *o = p_script;
#ifdef DEBUG_ENABLED
			ERR_FAIL_INDEX_V(address, _global_names_count, NULL);
#endif
			const StringName *sn = &_global_names_ptr[address];

			while (o) {
				GDScript *s = o;
				while (s) {

					Map<StringName, Variant>::Element *E = s->constants.find(*sn);
					if (E) {
						return &E->get();
					}
					s = s->_base;
				}
				o = o->_owner;
			}

			ERR_EXPLAIN("GDScriptCompiler bug...");
			ERR_FAIL_V(NULL);
		} break;
		case ADDR_TYPE_LOCAL_CONSTANT: {
#ifdef DEBUG_ENABLED
			ERR_FAIL_INDEX_V(address, _constant_count, NULL);
#endif
			return &_constants_ptr[address];
		} break;
		case ADDR_TYPE_STACK:
		case ADDR_TYPE_STACK_VARIABLE: {
#ifdef DEBUG_ENABLED
			ERR_FAIL_INDEX_V(address, _stack_size, NULL);
#endif
			return &p_stack[address];
		} break;
		case ADDR_TYPE_GLOBAL: {
#ifdef DEBUG_ENABLED
			ERR_FAIL_INDEX_V(address, GDScriptLanguage::get_singleton()->get_global_array_size(), NULL);
#endif
			return &GDScriptLanguage::get_singleton()->get_global_array()[address];
		} break;
#ifdef TOOLS_ENABLED
		case ADDR_TYPE_NAMED_GLOBAL: {
#ifdef DEBUG_ENABLED
			ERR_FAIL_INDEX_V(address, _named_globals_count, NULL);
#endif
			StringName id = _named_globals_ptr[address];

			if (GDScriptLanguage::get_singleton()->get_named_globals_map().has(id)) {
				return (Variant *)&GDScriptLanguage::get_singleton()->get_named_globals_map()[id];
			} else {
				r_error = "Autoload singleton '" + String(id) + "' has been removed.";
				return NULL;
			}
		} break;
#endif
		case ADDR_TYPE_NIL: {
			return &nil;
		} break;
	}

	ERR_EXPLAIN("Bad Code! (Addressing Mode)");
	ERR_FAIL_V(NULL);
	return NULL;
}

String GDScriptFunction::_get_call_error(const Variant::CallError &p_err, const String &p_where, const Variant **argptrs) const {

	String err_text;

	if (p_err.error == Variant::CallError::CALL_ERROR_INVALID_ARGUMENT) {
		int errorarg = p_err.argument;
		err_text = "Invalid type in " + p_where + ". Cannot convert argument " + itos(errorarg + 1) + " from " + Variant::get_type_name(argptrs[errorarg]->get_type()) + " to " + Variant::get_type_name(p_err.expected) + ".";
	} else if (p_err.error == Variant::CallError::CALL_ERROR_TOO_MANY_ARGUMENTS) {
		err_text = "Invalid call to " + p_where + ". Expected " + itos(p_err.argument) + " arguments.";
	} else if (p_err.error == Variant::CallError::CALL_ERROR_TOO_FEW_ARGUMENTS) {
		err_text = "Invalid call to " + p_where + ". Expected " + itos(p_err.argument) + " arguments.";
	} else if (p_err.error == Variant::CallError::CALL_ERROR_INVALID_METHOD) {
		err_text = "Invalid call. Nonexistent " + p_where + ".";
	} else if (p_err.error == Variant::CallError::CALL_ERROR_INSTANCE_IS_NULL) {
		err_text = "Attempt to call " + p_where + " on a null instance.";
	} else {
		err_text = "Bug, call error: #" + itos(p_err.error);
	}

	return err_text;
}

static String _get_var_type(const Variant *p_type) {

	String basestr;

	if (p_type->get_type() == Variant::OBJECT) {
		Object *bobj = *p_type;
		if (!bobj) {
			basestr = "null instance";
		} else {
#ifdef DEBUG_ENABLED
			if (ObjectDB::instance_validate(bobj)) {
				if (bobj->get_script_instance())
					basestr = bobj->get_class() + " (" + bobj->get_script_instance()->get_script()->get_path().get_file() + ")";
				else
					basestr = bobj->get_class();
			} else {
				basestr = "previously freed instance";
			}

#else
			basestr = "Object";
#endif
		}

	} else {
		basestr = Variant::get_type_name(p_type->get_type());
	}

	return basestr;
}

#if defined(__GNUC__)
#define OPCODES_TABLE                         \
	static const void *switch_table_ops[] = { \
		&&OPCODE_OPERATOR,                    \
		&&OPCODE_EXTENDS_TEST,                \
		&&OPCODE_SET,                         \
		&&OPCODE_GET,                         \
		&&OPCODE_SET_NAMED,                   \
		&&OPCODE_GET_NAMED,                   \
		&&OPCODE_SET_MEMBER,                  \
		&&OPCODE_GET_MEMBER,                  \
		&&OPCODE_ASSIGN,                      \
		&&OPCODE_ASSIGN_TRUE,                 \
		&&OPCODE_ASSIGN_FALSE,                \
		&&OPCODE_CONSTRUCT,                   \
		&&OPCODE_CONSTRUCT_ARRAY,             \
		&&OPCODE_CONSTRUCT_DICTIONARY,        \
		&&OPCODE_CALL,                        \
		&&OPCODE_CALL_RETURN,                 \
		&&OPCODE_CALL_BUILT_IN,               \
		&&OPCODE_CALL_SELF,                   \
		&&OPCODE_CALL_SELF_BASE,              \
		&&OPCODE_YIELD,                       \
		&&OPCODE_YIELD_SIGNAL,                \
		&&OPCODE_YIELD_RESUME,                \
		&&OPCODE_JUMP,                        \
		&&OPCODE_JUMP_IF,                     \
		&&OPCODE_JUMP_IF_NOT,                 \
		&&OPCODE_JUMP_TO_DEF_ARGUMENT,        \
		&&OPCODE_RETURN,                      \
		&&OPCODE_ITERATE_BEGIN,               \
		&&OPCODE_ITERATE,                     \
		&&OPCODE_ASSERT,                      \
		&&OPCODE_BREAKPOINT,                  \
		&&OPCODE_LINE,                        \
		&&OPCODE_END                          \
	};

#define OPCODE(m_op) \
	m_op:
#define OPCODE_WHILE(m_test)
#define OPCODES_END \
	OPSEXIT:
#define OPCODES_OUT \
	OPSOUT:
#define DISPATCH_OPCODE goto *switch_table_ops[_code_ptr[ip]]
#define OPCODE_SWITCH(m_test) DISPATCH_OPCODE;
#define OPCODE_BREAK goto OPSEXIT
#define OPCODE_OUT goto OPSOUT
#else
#define OPCODES_TABLE
#define OPCODE(m_op) case m_op:
#define OPCODE_WHILE(m_test) while (m_test)
#define OPCODES_END
#define OPCODES_OUT
#define DISPATCH_OPCODE continue
#define OPCODE_SWITCH(m_test) switch (m_test)
#define OPCODE_BREAK break
#define OPCODE_OUT break
#endif

Variant GDScriptFunction::call(GDScriptInstance *p_instance, const Variant **p_args, int p_argcount, Variant::CallError &r_err, CallState *p_state) {

	OPCODES_TABLE;

	if (!_code_ptr) {

		return Variant();
	}

	r_err.error = Variant::CallError::CALL_OK;

	Variant self;
	Variant retvalue;
	Variant *stack = NULL;
	Variant **call_args;
	int defarg = 0;

#ifdef DEBUG_ENABLED

	//GDScriptLanguage::get_singleton()->calls++;

#endif

	uint32_t alloca_size = 0;
	GDScript *_class;
	int ip = 0;
	int line = _initial_line;

	if (p_state) {
		//use existing (supplied) state (yielded)
		stack = (Variant *)p_state->stack.ptr();
		call_args = (Variant **)&p_state->stack.ptr()[sizeof(Variant) * p_state->stack_size]; //ptr() to avoid bounds check
		line = p_state->line;
		ip = p_state->ip;
		alloca_size = p_state->stack.size();
		_class = p_state->_class;
		p_instance = p_state->instance;
		defarg = p_state->defarg;
		self = p_state->self;
		//stack[p_state->result_pos]=p_state->result; //assign stack with result

	} else {

		if (p_argcount != _argument_count) {

			if (p_argcount > _argument_count) {

				r_err.error = Variant::CallError::CALL_ERROR_TOO_MANY_ARGUMENTS;
				r_err.argument = _argument_count;

				return Variant();
			} else if (p_argcount < _argument_count - _default_arg_count) {

				r_err.error = Variant::CallError::CALL_ERROR_TOO_FEW_ARGUMENTS;
				r_err.argument = _argument_count - _default_arg_count;
				return Variant();
			} else {

				defarg = _argument_count - p_argcount;
			}
		}

		alloca_size = sizeof(Variant *) * _call_size + sizeof(Variant) * _stack_size;

		if (alloca_size) {

			uint8_t *aptr = (uint8_t *)alloca(alloca_size);

			if (_stack_size) {

				stack = (Variant *)aptr;
				for (int i = 0; i < p_argcount; i++)
					memnew_placement(&stack[i], Variant(*p_args[i]));
				for (int i = p_argcount; i < _stack_size; i++)
					memnew_placement(&stack[i], Variant);
			} else {
				stack = NULL;
			}

			if (_call_size) {

				call_args = (Variant **)&aptr[sizeof(Variant) * _stack_size];
			} else {

				call_args = NULL;
			}

		} else {
			stack = NULL;
			call_args = NULL;
		}

		if (p_instance) {
			if (p_instance->base_ref && static_cast<Reference *>(p_instance->owner)->is_referenced()) {

				self = REF(static_cast<Reference *>(p_instance->owner));
			} else {
				self = p_instance->owner;
			}
			_class = p_instance->script.ptr();
		} else {
			_class = _script;
		}
	}

	String err_text;

#ifdef DEBUG_ENABLED

	if (ScriptDebugger::get_singleton())
		GDScriptLanguage::get_singleton()->enter_function(p_instance, this, stack, &ip, &line);

#define GD_ERR_BREAK(m_cond)                                                                                           \
	{                                                                                                                  \
		if (unlikely(m_cond)) {                                                                                        \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Condition ' " _STR(m_cond) " ' is true. Breaking..:"); \
			OPCODE_BREAK;                                                                                              \
		} else                                                                                                         \
			_err_error_exists = false;                                                                                 \
	}

#define CHECK_SPACE(m_space) \
	GD_ERR_BREAK((ip + m_space) > _code_size)

#define GET_VARIANT_PTR(m_v, m_code_ofs)                                                       \
	Variant *m_v;                                                                              \
	m_v = _get_variant(_code_ptr[ip + m_code_ofs], p_instance, _class, self, stack, err_text); \
	if (unlikely(!m_v))                                                                        \
		OPCODE_BREAK;

#else
#define GD_ERR_BREAK(m_cond)
#define CHECK_SPACE(m_space)
#define GET_VARIANT_PTR(m_v, m_code_ofs) \
	Variant *m_v;                        \
	m_v = _get_variant(_code_ptr[ip + m_code_ofs], p_instance, _class, self, stack, err_text);

#endif

#ifdef DEBUG_ENABLED

	uint64_t function_start_time = 0;
	uint64_t function_call_time = 0;

	if (GDScriptLanguage::get_singleton()->profiling) {
		function_start_time = OS::get_singleton()->get_ticks_usec();
		function_call_time = 0;
		profile.call_count++;
		profile.frame_call_count++;
	}
#endif
	bool exit_ok = false;

#ifdef DEBUG_ENABLED
	OPCODE_WHILE(ip < _code_size) {
		int last_opcode = _code_ptr[ip];
#else
	OPCODE_WHILE(true) {
#endif

		OPCODE_SWITCH(_code_ptr[ip]) {

			OPCODE(OPCODE_OPERATOR) {

				CHECK_SPACE(5);

				bool valid;
				Variant::Operator op = (Variant::Operator)_code_ptr[ip + 1];
				GD_ERR_BREAK(op >= Variant::OP_MAX);

				GET_VARIANT_PTR(a, 2);
				GET_VARIANT_PTR(b, 3);
				GET_VARIANT_PTR(dst, 4);

#ifdef DEBUG_ENABLED

				Variant ret;
				Variant::evaluate(op, *a, *b, ret, valid);
#else
				Variant::evaluate(op, *a, *b, *dst, valid);
#endif
#ifdef DEBUG_ENABLED
				if (!valid) {

					if (ret.get_type() == Variant::STRING) {
						//return a string when invalid with the error
						err_text = ret;
						err_text += " in operator '" + Variant::get_operator_name(op) + "'.";
					} else {
						err_text = "Invalid operands '" + Variant::get_type_name(a->get_type()) + "' and '" + Variant::get_type_name(b->get_type()) + "' in operator '" + Variant::get_operator_name(op) + "'.";
					}
					OPCODE_BREAK;
				}
				*dst = ret;
#endif
				ip += 5;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_EXTENDS_TEST) {

				CHECK_SPACE(4);

				GET_VARIANT_PTR(a, 1);
				GET_VARIANT_PTR(b, 2);
				GET_VARIANT_PTR(dst, 3);

#ifdef DEBUG_ENABLED
				if (a->get_type() != Variant::OBJECT || a->operator Object *() == NULL) {

					err_text = "Left operand of 'is' is not an instance of anything.";
					OPCODE_BREAK;
				}
				if (b->get_type() != Variant::OBJECT || b->operator Object *() == NULL) {

					err_text = "Right operand of 'is' is not a class.";
					OPCODE_BREAK;
				}
#endif
				Object *obj_A = *a;
				Object *obj_B = *b;

				GDScript *scr_B = Object::cast_to<GDScript>(obj_B);

				bool extends_ok = false;

				if (scr_B) {
					//if B is a script, the only valid condition is that A has an instance which inherits from the script
					//in other situation, this shoul return false.

					if (obj_A->get_script_instance() && obj_A->get_script_instance()->get_language() == GDScriptLanguage::get_singleton()) {

						GDScript *cmp = static_cast<GDScript *>(obj_A->get_script_instance()->get_script().ptr());
						//bool found=false;
						while (cmp) {

							if (cmp == scr_B) {
								//inherits from script, all ok
								extends_ok = true;
								break;
							}

							cmp = cmp->_base;
						}
					}

				} else {

					GDScriptNativeClass *nc = Object::cast_to<GDScriptNativeClass>(obj_B);

#ifdef DEBUG_ENABLED
					if (!nc) {

						err_text = "Right operand of 'is' is not a class (type: '" + obj_B->get_class() + "').";
						OPCODE_BREAK;
					}
#endif
					extends_ok = ClassDB::is_parent_class(obj_A->get_class_name(), nc->get_name());
				}

				*dst = extends_ok;
				ip += 4;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_SET) {

				CHECK_SPACE(3);

				GET_VARIANT_PTR(dst, 1);
				GET_VARIANT_PTR(index, 2);
				GET_VARIANT_PTR(value, 3);

				bool valid;
				dst->set(*index, *value, &valid);

#ifdef DEBUG_ENABLED
				if (!valid) {
					String v = index->operator String();
					if (v != "") {
						v = "'" + v + "'";
					} else {
						v = "of type '" + _get_var_type(index) + "'";
					}
					err_text = "Invalid set index " + v + " (on base: '" + _get_var_type(dst) + "') with value of type '" + _get_var_type(value) + "'";
					OPCODE_BREAK;
				}
#endif
				ip += 4;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_GET) {

				CHECK_SPACE(3);

				GET_VARIANT_PTR(src, 1);
				GET_VARIANT_PTR(index, 2);
				GET_VARIANT_PTR(dst, 3);

				bool valid;
#ifdef DEBUG_ENABLED
				//allow better error message in cases where src and dst are the same stack position
				Variant ret = src->get(*index, &valid);
#else
				*dst = src->get(*index, &valid);

#endif
#ifdef DEBUG_ENABLED
				if (!valid) {
					String v = index->operator String();
					if (v != "") {
						v = "'" + v + "'";
					} else {
						v = "of type '" + _get_var_type(index) + "'";
					}
					err_text = "Invalid get index " + v + " (on base: '" + _get_var_type(src) + "').";
					OPCODE_BREAK;
				}
				*dst = ret;
#endif
				ip += 4;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_SET_NAMED) {

				CHECK_SPACE(3);

				GET_VARIANT_PTR(dst, 1);
				GET_VARIANT_PTR(value, 3);

				int indexname = _code_ptr[ip + 2];

				GD_ERR_BREAK(indexname < 0 || indexname >= _global_names_count);
				const StringName *index = &_global_names_ptr[indexname];

				bool valid;
				dst->set_named(*index, *value, &valid);

#ifdef DEBUG_ENABLED
				if (!valid) {
					String err_type;
					err_text = "Invalid set index '" + String(*index) + "' (on base: '" + _get_var_type(dst) + "') with value of type '" + _get_var_type(value) + "'.";
					OPCODE_BREAK;
				}
#endif
				ip += 4;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_GET_NAMED) {

				CHECK_SPACE(4);

				GET_VARIANT_PTR(src, 1);
				GET_VARIANT_PTR(dst, 3);

				int indexname = _code_ptr[ip + 2];

				GD_ERR_BREAK(indexname < 0 || indexname >= _global_names_count);
				const StringName *index = &_global_names_ptr[indexname];

				bool valid;
#ifdef DEBUG_ENABLED
				//allow better error message in cases where src and dst are the same stack position
				Variant ret = src->get_named(*index, &valid);

#else
				*dst = src->get_named(*index, &valid);
#endif
#ifdef DEBUG_ENABLED
				if (!valid) {
					if (src->has_method(*index)) {
						err_text = "Invalid get index '" + index->operator String() + "' (on base: '" + _get_var_type(src) + "'). Did you mean '." + index->operator String() + "()' or funcref(obj, \"" + index->operator String() + "\") ?";
					} else {
						err_text = "Invalid get index '" + index->operator String() + "' (on base: '" + _get_var_type(src) + "').";
					}
					OPCODE_BREAK;
				}
				*dst = ret;
#endif
				ip += 4;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_SET_MEMBER) {

				CHECK_SPACE(3);
				int indexname = _code_ptr[ip + 1];
				GD_ERR_BREAK(indexname < 0 || indexname >= _global_names_count);
				const StringName *index = &_global_names_ptr[indexname];
				GET_VARIANT_PTR(src, 2);

				bool valid;
				bool ok = ClassDB::set_property(p_instance->owner, *index, *src, &valid);
#ifdef DEBUG_ENABLED
				if (!ok) {
					err_text = "Internal error setting property: " + String(*index);
					OPCODE_BREAK;
				} else if (!valid) {
					err_text = "Error setting property '" + String(*index) + "' with value of type " + Variant::get_type_name(src->get_type()) + ".";
					OPCODE_BREAK;
				}
#endif
				ip += 3;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_GET_MEMBER) {

				CHECK_SPACE(3);
				int indexname = _code_ptr[ip + 1];
				GD_ERR_BREAK(indexname < 0 || indexname >= _global_names_count);
				const StringName *index = &_global_names_ptr[indexname];
				GET_VARIANT_PTR(dst, 2);
				bool ok = ClassDB::get_property(p_instance->owner, *index, *dst);

#ifdef DEBUG_ENABLED
				if (!ok) {
					err_text = "Internal error getting property: " + String(*index);
					OPCODE_BREAK;
				}
#endif
				ip += 3;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_ASSIGN) {

				CHECK_SPACE(3);
				GET_VARIANT_PTR(dst, 1);
				GET_VARIANT_PTR(src, 2);

				*dst = *src;

				ip += 3;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_ASSIGN_TRUE) {

				CHECK_SPACE(2);
				GET_VARIANT_PTR(dst, 1);

				*dst = true;

				ip += 2;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_ASSIGN_FALSE) {

				CHECK_SPACE(2);
				GET_VARIANT_PTR(dst, 1);

				*dst = false;

				ip += 2;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_CONSTRUCT) {

				CHECK_SPACE(2);
				Variant::Type t = Variant::Type(_code_ptr[ip + 1]);
				int argc = _code_ptr[ip + 2];
				CHECK_SPACE(argc + 2);
				Variant **argptrs = call_args;
				for (int i = 0; i < argc; i++) {
					GET_VARIANT_PTR(v, 3 + i);
					argptrs[i] = v;
				}

				GET_VARIANT_PTR(dst, 3 + argc);
				Variant::CallError err;
				*dst = Variant::construct(t, (const Variant **)argptrs, argc, err);

#ifdef DEBUG_ENABLED
				if (err.error != Variant::CallError::CALL_OK) {

					err_text = _get_call_error(err, "'" + Variant::get_type_name(t) + "' constructor", (const Variant **)argptrs);
					OPCODE_BREAK;
				}
#endif

				ip += 4 + argc;
				//construct a basic type
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_CONSTRUCT_ARRAY) {

				CHECK_SPACE(1);
				int argc = _code_ptr[ip + 1];
				Array array; //arrays are always shared
				array.resize(argc);
				CHECK_SPACE(argc + 2);

				for (int i = 0; i < argc; i++) {
					GET_VARIANT_PTR(v, 2 + i);
					array[i] = *v;
				}

				GET_VARIANT_PTR(dst, 2 + argc);

				*dst = array;

				ip += 3 + argc;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_CONSTRUCT_DICTIONARY) {

				CHECK_SPACE(1);
				int argc = _code_ptr[ip + 1];
				Dictionary dict; //arrays are always shared

				CHECK_SPACE(argc * 2 + 2);

				for (int i = 0; i < argc; i++) {

					GET_VARIANT_PTR(k, 2 + i * 2 + 0);
					GET_VARIANT_PTR(v, 2 + i * 2 + 1);
					dict[*k] = *v;
				}

				GET_VARIANT_PTR(dst, 2 + argc * 2);

				*dst = dict;

				ip += 3 + argc * 2;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_CALL_RETURN)
			OPCODE(OPCODE_CALL) {

				CHECK_SPACE(4);
				bool call_ret = _code_ptr[ip] == OPCODE_CALL_RETURN;

				int argc = _code_ptr[ip + 1];
				GET_VARIANT_PTR(base, 2);
				int nameg = _code_ptr[ip + 3];

				GD_ERR_BREAK(nameg < 0 || nameg >= _global_names_count);
				const StringName *methodname = &_global_names_ptr[nameg];

				GD_ERR_BREAK(argc < 0);
				ip += 4;
				CHECK_SPACE(argc + 1);
				Variant **argptrs = call_args;

				for (int i = 0; i < argc; i++) {
					GET_VARIANT_PTR(v, i);
					argptrs[i] = v;
				}

#ifdef DEBUG_ENABLED
				uint64_t call_time = 0;

				if (GDScriptLanguage::get_singleton()->profiling) {
					call_time = OS::get_singleton()->get_ticks_usec();
				}

#endif
				Variant::CallError err;
				if (call_ret) {

					GET_VARIANT_PTR(ret, argc);
					base->call_ptr(*methodname, (const Variant **)argptrs, argc, ret, err);
				} else {

					base->call_ptr(*methodname, (const Variant **)argptrs, argc, NULL, err);
				}
#ifdef DEBUG_ENABLED
				if (GDScriptLanguage::get_singleton()->profiling) {
					function_call_time += OS::get_singleton()->get_ticks_usec() - call_time;
				}

				if (err.error != Variant::CallError::CALL_OK) {

					String methodstr = *methodname;
					String basestr = _get_var_type(base);

					if (methodstr == "call") {
						if (argc >= 1) {
							methodstr = String(*argptrs[0]) + " (via call)";
							if (err.error == Variant::CallError::CALL_ERROR_INVALID_ARGUMENT) {
								err.argument -= 1;
							}
						}
					} else if (methodstr == "free") {

						if (err.error == Variant::CallError::CALL_ERROR_INVALID_METHOD) {

							if (base->is_ref()) {
								err_text = "Attempted to free a reference.";
								OPCODE_BREAK;
							} else if (base->get_type() == Variant::OBJECT) {

								err_text = "Attempted to free a locked object (calling or emitting).";
								OPCODE_BREAK;
							}
						}
					}
					err_text = _get_call_error(err, "function '" + methodstr + "' in base '" + basestr + "'", (const Variant **)argptrs);
					OPCODE_BREAK;
				}
#endif

				//_call_func(NULL,base,*methodname,ip,argc,p_instance,stack);
				ip += argc + 1;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_CALL_BUILT_IN) {

				CHECK_SPACE(4);

				GDScriptFunctions::Function func = GDScriptFunctions::Function(_code_ptr[ip + 1]);
				int argc = _code_ptr[ip + 2];
				GD_ERR_BREAK(argc < 0);

				ip += 3;
				CHECK_SPACE(argc + 1);
				Variant **argptrs = call_args;

				for (int i = 0; i < argc; i++) {
					GET_VARIANT_PTR(v, i);
					argptrs[i] = v;
				}

				GET_VARIANT_PTR(dst, argc);

				Variant::CallError err;

				GDScriptFunctions::call(func, (const Variant **)argptrs, argc, *dst, err);

#ifdef DEBUG_ENABLED
				if (err.error != Variant::CallError::CALL_OK) {

					String methodstr = GDScriptFunctions::get_func_name(func);
					if (dst->get_type() == Variant::STRING) {
						//call provided error string
						err_text = "Error calling built-in function '" + methodstr + "': " + String(*dst);
					} else {
						err_text = _get_call_error(err, "built-in function '" + methodstr + "'", (const Variant **)argptrs);
					}
					OPCODE_BREAK;
				}
#endif
				ip += argc + 1;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_CALL_SELF) {

				OPCODE_BREAK;
			}

			OPCODE(OPCODE_CALL_SELF_BASE) {

				CHECK_SPACE(2);
				int self_fun = _code_ptr[ip + 1];

#ifdef DEBUG_ENABLED
				if (self_fun < 0 || self_fun >= _global_names_count) {

					err_text = "compiler bug, function name not found";
					OPCODE_BREAK;
				}
#endif
				const StringName *methodname = &_global_names_ptr[self_fun];

				int argc = _code_ptr[ip + 2];

				CHECK_SPACE(2 + argc + 1);

				Variant **argptrs = call_args;

				for (int i = 0; i < argc; i++) {
					GET_VARIANT_PTR(v, i + 3);
					argptrs[i] = v;
				}

				GET_VARIANT_PTR(dst, argc + 3);

				const GDScript *gds = _script;

				const Map<StringName, GDScriptFunction *>::Element *E = NULL;
				while (gds->base.ptr()) {
					gds = gds->base.ptr();
					E = gds->member_functions.find(*methodname);
					if (E)
						break;
				}

				Variant::CallError err;

				if (E) {

					*dst = E->get()->call(p_instance, (const Variant **)argptrs, argc, err);
				} else if (gds->native.ptr()) {

					if (*methodname != GDScriptLanguage::get_singleton()->strings._init) {

						MethodBind *mb = ClassDB::get_method(gds->native->get_name(), *methodname);
						if (!mb) {
							err.error = Variant::CallError::CALL_ERROR_INVALID_METHOD;
						} else {
							*dst = mb->call(p_instance->owner, (const Variant **)argptrs, argc, err);
						}
					} else {
						err.error = Variant::CallError::CALL_OK;
					}
				} else {

					if (*methodname != GDScriptLanguage::get_singleton()->strings._init) {
						err.error = Variant::CallError::CALL_ERROR_INVALID_METHOD;
					} else {
						err.error = Variant::CallError::CALL_OK;
					}
				}

				if (err.error != Variant::CallError::CALL_OK) {

					String methodstr = *methodname;
					err_text = _get_call_error(err, "function '" + methodstr + "'", (const Variant **)argptrs);

					OPCODE_BREAK;
				}

				ip += 4 + argc;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_YIELD)
			OPCODE(OPCODE_YIELD_SIGNAL) {

				int ipofs = 1;
				if (_code_ptr[ip] == OPCODE_YIELD_SIGNAL) {
					CHECK_SPACE(4);
					ipofs += 2;
				} else {
					CHECK_SPACE(2);
				}

				Ref<GDScriptFunctionState> gdfs = memnew(GDScriptFunctionState);
				gdfs->function = this;

				gdfs->state.stack.resize(alloca_size);
				//copy variant stack
				for (int i = 0; i < _stack_size; i++) {
					memnew_placement(&gdfs->state.stack[sizeof(Variant) * i], Variant(stack[i]));
				}
				gdfs->state.stack_size = _stack_size;
				gdfs->state.self = self;
				gdfs->state.alloca_size = alloca_size;
				gdfs->state._class = _class;
				gdfs->state.ip = ip + ipofs;
				gdfs->state.line = line;
				gdfs->state.instance_id = (p_instance && p_instance->get_owner()) ? p_instance->get_owner()->get_instance_id() : 0;
				gdfs->state.script_id = _class->get_instance_id();
				//gdfs->state.result_pos=ip+ipofs-1;
				gdfs->state.defarg = defarg;
				gdfs->state.instance = p_instance;
				gdfs->function = this;

				retvalue = gdfs;

				if (_code_ptr[ip] == OPCODE_YIELD_SIGNAL) {
					//do the oneshot connect
					GET_VARIANT_PTR(argobj, 1);
					GET_VARIANT_PTR(argname, 2);

#ifdef DEBUG_ENABLED
					if (argobj->get_type() != Variant::OBJECT) {
						err_text = "First argument of yield() not of type object.";
						OPCODE_BREAK;
					}
					if (argname->get_type() != Variant::STRING) {
						err_text = "Second argument of yield() not a string (for signal name).";
						OPCODE_BREAK;
					}
#endif
					Object *obj = argobj->operator Object *();
					String signal = argname->operator String();
#ifdef DEBUG_ENABLED

					if (!obj) {
						err_text = "First argument of yield() is null.";
						OPCODE_BREAK;
					}
					if (ScriptDebugger::get_singleton()) {
						if (!ObjectDB::instance_validate(obj)) {
							err_text = "First argument of yield() is a previously freed instance.";
							OPCODE_BREAK;
						}
					}
					if (signal.length() == 0) {

						err_text = "Second argument of yield() is an empty string (for signal name).";
						OPCODE_BREAK;
					}

#endif
					Error err = obj->connect(signal, gdfs.ptr(), "_signal_callback", varray(gdfs), Object::CONNECT_ONESHOT);
#ifdef DEBUG_ENABLED
					if (err != OK) {
						err_text = "Error connecting to signal: " + signal + " during yield().";
						OPCODE_BREAK;
					}
#endif
				}

				exit_ok = true;
				OPCODE_BREAK;
			}

			OPCODE(OPCODE_YIELD_RESUME) {

				CHECK_SPACE(2);
#ifdef DEBUG_ENABLED
				if (!p_state) {
					err_text = ("Invalid Resume (bug?)");
					OPCODE_BREAK;
				}
#endif
				GET_VARIANT_PTR(result, 1);
				*result = p_state->result;
				ip += 2;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_JUMP) {

				CHECK_SPACE(2);
				int to = _code_ptr[ip + 1];

				GD_ERR_BREAK(to < 0 || to > _code_size);
				ip = to;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_JUMP_IF) {

				CHECK_SPACE(3);

				GET_VARIANT_PTR(test, 1);

				bool result = test->booleanize();

				if (result) {
					int to = _code_ptr[ip + 2];
					GD_ERR_BREAK(to < 0 || to > _code_size);
					ip = to;
				} else {
					ip += 3;
				}
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_JUMP_IF_NOT) {

				CHECK_SPACE(3);

				GET_VARIANT_PTR(test, 1);

				bool result = test->booleanize();

				if (!result) {
					int to = _code_ptr[ip + 2];
					GD_ERR_BREAK(to < 0 || to > _code_size);
					ip = to;
				} else {
					ip += 3;
				}
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_JUMP_TO_DEF_ARGUMENT) {

				CHECK_SPACE(2);
				ip = _default_arg_ptr[defarg];
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_RETURN) {

				CHECK_SPACE(2);
				GET_VARIANT_PTR(r, 1);
				retvalue = *r;
				exit_ok = true;
				OPCODE_BREAK;
			}

			OPCODE(OPCODE_ITERATE_BEGIN) {

				CHECK_SPACE(8); //space for this a regular iterate

				GET_VARIANT_PTR(counter, 1);
				GET_VARIANT_PTR(container, 2);

				bool valid;
				if (!container->iter_init(*counter, valid)) {
#ifdef DEBUG_ENABLED
					if (!valid) {
						err_text = "Unable to iterate on object of type  " + Variant::get_type_name(container->get_type()) + "'.";
						OPCODE_BREAK;
					}
#endif
					int jumpto = _code_ptr[ip + 3];
					GD_ERR_BREAK(jumpto < 0 || jumpto > _code_size);
					ip = jumpto;
				} else {
					GET_VARIANT_PTR(iterator, 4);

					*iterator = container->iter_get(*counter, valid);
#ifdef DEBUG_ENABLED
					if (!valid) {
						err_text = "Unable to obtain iterator object of type  " + Variant::get_type_name(container->get_type()) + "'.";
						OPCODE_BREAK;
					}
#endif
					ip += 5; //skip regular iterate which is always next
				}
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_ITERATE) {

				CHECK_SPACE(4);

				GET_VARIANT_PTR(counter, 1);
				GET_VARIANT_PTR(container, 2);

				bool valid;
				if (!container->iter_next(*counter, valid)) {
#ifdef DEBUG_ENABLED
					if (!valid) {
						err_text = "Unable to iterate on object of type  " + Variant::get_type_name(container->get_type()) + "' (type changed since first iteration?).";
						OPCODE_BREAK;
					}
#endif
					int jumpto = _code_ptr[ip + 3];
					GD_ERR_BREAK(jumpto < 0 || jumpto > _code_size);
					ip = jumpto;
				} else {
					GET_VARIANT_PTR(iterator, 4);

					*iterator = container->iter_get(*counter, valid);
#ifdef DEBUG_ENABLED
					if (!valid) {
						err_text = "Unable to obtain iterator object of type  " + Variant::get_type_name(container->get_type()) + "' (but was obtained on first iteration?).";
						OPCODE_BREAK;
					}
#endif
					ip += 5; //loop again
				}
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_ASSERT) {
				CHECK_SPACE(2);
				GET_VARIANT_PTR(test, 1);

#ifdef DEBUG_ENABLED
				bool result = test->booleanize();

				if (!result) {

					err_text = "Assertion failed.";
					OPCODE_BREAK;
				}

#endif
				ip += 2;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_BREAKPOINT) {
#ifdef DEBUG_ENABLED
				if (ScriptDebugger::get_singleton()) {
					GDScriptLanguage::get_singleton()->debug_break("Breakpoint Statement", true);
				}
#endif
				ip += 1;
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_LINE) {
				CHECK_SPACE(2);

				line = _code_ptr[ip + 1];
				ip += 2;

				if (ScriptDebugger::get_singleton()) {
					// line
					bool do_break = false;

					if (ScriptDebugger::get_singleton()->get_lines_left() > 0) {

						if (ScriptDebugger::get_singleton()->get_depth() <= 0)
							ScriptDebugger::get_singleton()->set_lines_left(ScriptDebugger::get_singleton()->get_lines_left() - 1);
						if (ScriptDebugger::get_singleton()->get_lines_left() <= 0)
							do_break = true;
					}

					if (ScriptDebugger::get_singleton()->is_breakpoint(line, source))
						do_break = true;

					if (do_break) {
						GDScriptLanguage::get_singleton()->debug_break("Breakpoint", true);
					}

					ScriptDebugger::get_singleton()->line_poll();
				}
			}
			DISPATCH_OPCODE;

			OPCODE(OPCODE_END) {

				exit_ok = true;
				OPCODE_BREAK;
			}

// Enable for debugging
#if 0
			default: {

				err_text = "Illegal opcode " + itos(_code_ptr[ip]) + " at address " + itos(ip);
				OPCODE_BREAK;
			}
#endif
		}

		OPCODES_END
#ifdef DEBUG_ENABLED
		if (exit_ok)
			OPCODE_OUT;
		//error
		// function, file, line, error, explanation
		String err_file;
		if (p_instance)
			err_file = p_instance->script->path;
		else if (_class)
			err_file = _class->path;
		if (err_file == "")
			err_file = "<built-in>";
		String err_func = name;
		if (p_instance && p_instance->script->name != "")
			err_func = p_instance->script->name + "." + err_func;
		int err_line = line;
		if (err_text == "") {
			err_text = "Internal Script Error! - opcode #" + itos(last_opcode) + " (report please).";
		}

		if (!GDScriptLanguage::get_singleton()->debug_break(err_text, false)) {
			// debugger break did not happen

			_err_print_error(err_func.utf8().get_data(), err_file.utf8().get_data(), err_line, err_text.utf8().get_data(), ERR_HANDLER_SCRIPT);
		}

#endif
		OPCODE_OUT;
	}

	OPCODES_OUT
#ifdef DEBUG_ENABLED
	if (GDScriptLanguage::get_singleton()->profiling) {
		uint64_t time_taken = OS::get_singleton()->get_ticks_usec() - function_start_time;
		profile.total_time += time_taken;
		profile.self_time += time_taken - function_call_time;
		profile.frame_total_time += time_taken;
		profile.frame_self_time += time_taken - function_call_time;
		GDScriptLanguage::get_singleton()->script_frame_time += time_taken - function_call_time;
	}

	if (ScriptDebugger::get_singleton())
		GDScriptLanguage::get_singleton()->exit_function();
#endif

	if (_stack_size) {
		//free stack
		for (int i = 0; i < _stack_size; i++)
			stack[i].~Variant();
	}

	return retvalue;
}

const int *GDScriptFunction::get_code() const {

	return _code_ptr;
}
int GDScriptFunction::get_code_size() const {

	return _code_size;
}

Variant GDScriptFunction::get_constant(int p_idx) const {

	ERR_FAIL_INDEX_V(p_idx, constants.size(), "<errconst>");
	return constants[p_idx];
}

StringName GDScriptFunction::get_global_name(int p_idx) const {

	ERR_FAIL_INDEX_V(p_idx, global_names.size(), "<errgname>");
	return global_names[p_idx];
}

int GDScriptFunction::get_default_argument_count() const {

	return default_arguments.size();
}
int GDScriptFunction::get_default_argument_addr(int p_idx) const {

	ERR_FAIL_INDEX_V(p_idx, default_arguments.size(), -1);
	return default_arguments[p_idx];
}

GDScriptDataType GDScriptFunction::get_return_type() const {
	return return_type;
}

GDScriptDataType GDScriptFunction::get_argument_type(int p_idx) const {
	ERR_FAIL_INDEX_V(p_idx, argument_types.size(), GDScriptDataType());
	return argument_types[p_idx];
}

StringName GDScriptFunction::get_name() const {

	return name;
}

int GDScriptFunction::get_max_stack_size() const {

	return _stack_size;
}

struct _GDFKC {

	int order;
	List<int> pos;
};

struct _GDFKCS {

	int order;
	StringName id;
	int pos;

	bool operator<(const _GDFKCS &p_r) const {

		return order < p_r.order;
	}
};

void GDScriptFunction::debug_get_stack_member_state(int p_line, List<Pair<StringName, int> > *r_stackvars) const {

	int oc = 0;
	Map<StringName, _GDFKC> sdmap;
	for (const List<StackDebug>::Element *E = stack_debug.front(); E; E = E->next()) {

		const StackDebug &sd = E->get();
		if (sd.line > p_line)
			break;

		if (sd.added) {

			if (!sdmap.has(sd.identifier)) {
				_GDFKC d;
				d.order = oc++;
				d.pos.push_back(sd.pos);
				sdmap[sd.identifier] = d;

			} else {
				sdmap[sd.identifier].pos.push_back(sd.pos);
			}
		} else {

			ERR_CONTINUE(!sdmap.has(sd.identifier));

			sdmap[sd.identifier].pos.pop_back();
			if (sdmap[sd.identifier].pos.empty())
				sdmap.erase(sd.identifier);
		}
	}

	List<_GDFKCS> stackpositions;
	for (Map<StringName, _GDFKC>::Element *E = sdmap.front(); E; E = E->next()) {

		_GDFKCS spp;
		spp.id = E->key();
		spp.order = E->get().order;
		spp.pos = E->get().pos.back()->get();
		stackpositions.push_back(spp);
	}

	stackpositions.sort();

	for (List<_GDFKCS>::Element *E = stackpositions.front(); E; E = E->next()) {

		Pair<StringName, int> p;
		p.first = E->get().id;
		p.second = E->get().pos;
		r_stackvars->push_back(p);
	}
}

GDScriptFunction::GDScriptFunction() :
		function_list(this) {

	_stack_size = 0;
	_call_size = 0;
	rpc_mode = MultiplayerAPI::RPC_MODE_DISABLED;
	name = "<anonymous>";
#ifdef DEBUG_ENABLED
	_func_cname = NULL;

	if (GDScriptLanguage::get_singleton()->lock) {
		GDScriptLanguage::get_singleton()->lock->lock();
	}
	GDScriptLanguage::get_singleton()->function_list.add(&function_list);

	if (GDScriptLanguage::get_singleton()->lock) {
		GDScriptLanguage::get_singleton()->lock->unlock();
	}

	profile.call_count = 0;
	profile.self_time = 0;
	profile.total_time = 0;
	profile.frame_call_count = 0;
	profile.frame_self_time = 0;
	profile.frame_total_time = 0;
	profile.last_frame_call_count = 0;
	profile.last_frame_self_time = 0;
	profile.last_frame_total_time = 0;

#endif
}

GDScriptFunction::~GDScriptFunction() {
#ifdef DEBUG_ENABLED
	if (GDScriptLanguage::get_singleton()->lock) {
		GDScriptLanguage::get_singleton()->lock->lock();
	}
	GDScriptLanguage::get_singleton()->function_list.remove(&function_list);

	if (GDScriptLanguage::get_singleton()->lock) {
		GDScriptLanguage::get_singleton()->lock->unlock();
	}
#endif
}

/////////////////////

Variant GDScriptFunctionState::_signal_callback(const Variant **p_args, int p_argcount, Variant::CallError &r_error) {

#ifdef DEBUG_ENABLED
	if (state.instance_id && !ObjectDB::get_instance(state.instance_id)) {
		ERR_EXPLAIN("Resumed after yield, but class instance is gone");
		ERR_FAIL_V(Variant());
	}

	if (state.script_id && !ObjectDB::get_instance(state.script_id)) {
		ERR_EXPLAIN("Resumed after yield, but script is gone");
		ERR_FAIL_V(Variant());
	}
#endif

	Variant arg;
	r_error.error = Variant::CallError::CALL_OK;

	ERR_FAIL_COND_V(!function, Variant());

	if (p_argcount == 0) {
		r_error.error = Variant::CallError::CALL_ERROR_TOO_FEW_ARGUMENTS;
		r_error.argument = 1;
		return Variant();
	} else if (p_argcount == 1) {
		//noooneee
	} else if (p_argcount == 2) {
		arg = *p_args[0];
	} else {
		Array extra_args;
		for (int i = 0; i < p_argcount - 1; i++) {
			extra_args.push_back(*p_args[i]);
		}
		arg = extra_args;
	}

	Ref<GDScriptFunctionState> self = *p_args[p_argcount - 1];

	if (self.is_null()) {
		r_error.error = Variant::CallError::CALL_ERROR_INVALID_ARGUMENT;
		r_error.argument = p_argcount - 1;
		r_error.expected = Variant::OBJECT;
		return Variant();
	}

	state.result = arg;
	Variant ret = function->call(NULL, NULL, 0, r_error, &state);

	bool completed = true;

	// If the return value is a GDScriptFunctionState reference,
	// then the function did yield again after resuming.
	if (ret.is_ref()) {
		GDScriptFunctionState *gdfs = Object::cast_to<GDScriptFunctionState>(ret);
		if (gdfs && gdfs->function == function) {
			completed = false;
			gdfs->first_state = first_state.is_valid() ? first_state : Ref<GDScriptFunctionState>(this);
		}
	}

	function = NULL; //cleaned up;
	state.result = Variant();

	if (completed) {
		if (first_state.is_valid()) {
			first_state->emit_signal("completed", ret);
		} else {
			emit_signal("completed", ret);
		}
	}

	return ret;
}

bool GDScriptFunctionState::is_valid(bool p_extended_check) const {

	if (function == NULL)
		return false;

	if (p_extended_check) {
		//class instance gone?
		if (state.instance_id && !ObjectDB::get_instance(state.instance_id))
			return false;
		//script gone?
		if (state.script_id && !ObjectDB::get_instance(state.script_id))
			return false;
	}

	return true;
}

Variant GDScriptFunctionState::resume(const Variant &p_arg) {

	ERR_FAIL_COND_V(!function, Variant());
#ifdef DEBUG_ENABLED
	if (state.instance_id && !ObjectDB::get_instance(state.instance_id)) {
		ERR_EXPLAIN("Resumed after yield, but class instance is gone");
		ERR_FAIL_V(Variant());
	}

	if (state.script_id && !ObjectDB::get_instance(state.script_id)) {
		ERR_EXPLAIN("Resumed after yield, but script is gone");
		ERR_FAIL_V(Variant());
	}
#endif

	state.result = p_arg;
	Variant::CallError err;
	Variant ret = function->call(NULL, NULL, 0, err, &state);

	bool completed = true;

	// If the return value is a GDScriptFunctionState reference,
	// then the function did yield again after resuming.
	if (ret.is_ref()) {
		GDScriptFunctionState *gdfs = Object::cast_to<GDScriptFunctionState>(ret);
		if (gdfs && gdfs->function == function) {
			completed = false;
			gdfs->first_state = first_state.is_valid() ? first_state : Ref<GDScriptFunctionState>(this);
		}
	}

	function = NULL; //cleaned up;
	state.result = Variant();

	if (completed) {
		if (first_state.is_valid()) {
			first_state->emit_signal("completed", ret);
		} else {
			emit_signal("completed", ret);
		}
	}

	return ret;
}

void GDScriptFunctionState::_bind_methods() {

	ClassDB::bind_method(D_METHOD("resume", "arg"), &GDScriptFunctionState::resume, DEFVAL(Variant()));
	ClassDB::bind_method(D_METHOD("is_valid", "extended_check"), &GDScriptFunctionState::is_valid, DEFVAL(false));
	ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "_signal_callback", &GDScriptFunctionState::_signal_callback, MethodInfo("_signal_callback"));

	ADD_SIGNAL(MethodInfo("completed", PropertyInfo(Variant::NIL, "result", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NIL_IS_VARIANT)));
}

GDScriptFunctionState::GDScriptFunctionState() {

	function = NULL;
}

GDScriptFunctionState::~GDScriptFunctionState() {

	if (function != NULL) {
		//never called, deinitialize stack
		for (int i = 0; i < state.stack_size; i++) {
			Variant *v = (Variant *)&state.stack[sizeof(Variant) * i];
			v->~Variant();
		}
	}
}