static PrimitiveResult callFn(WrenVM* vm, Value* args, int numArgs)
{
ObjFn* fn;
if (IS_CLOSURE(args[0]))
{
fn = AS_CLOSURE(args[0])->fn;
}
else
{
fn = AS_FN(args[0]);
}
if (numArgs < fn->arity) RETURN_ERROR("Function expects more arguments.");
return PRIM_CALL;
}
void metaCompile(WrenVM* vm)
{
// Evaluate the code in the module where the calling function was defined.
// That's one stack frame back from the top since the top-most frame is the
// helper eval() method in Meta itself.
Value callingFn = OBJ_VAL(vm->fiber->frames[vm->fiber->numFrames - 2].fn);
ObjModule* module = IS_FN(callingFn)
? AS_FN(callingFn)->module
: AS_CLOSURE(callingFn)->fn->module;
// Compile it.
ObjFn* fn = wrenCompile(vm, module, wrenGetArgumentString(vm, 1), false);
if (fn == NULL) return;
// Return the result. We can't use the public API for this since we have a
// bare ObjFn.
*vm->foreignCallSlot = OBJ_VAL(fn);
vm->foreignCallSlot = NULL;
}
static void bindMethod(WrenVM* vm, int methodType, int symbol,
ObjClass* classObj, Value methodValue)
{
ObjFn* methodFn = IS_FN(methodValue) ? AS_FN(methodValue)
: AS_CLOSURE(methodValue)->fn;
// Methods are always bound against the class, and not the metaclass, even
// for static methods, so that constructors (which are static) get bound like
// instance methods.
wrenBindMethodCode(classObj, methodFn);
Method method;
method.type = METHOD_BLOCK;
method.fn.obj = AS_OBJ(methodValue);
if (methodType == CODE_METHOD_STATIC)
{
classObj = classObj->obj.classObj;
}
wrenBindMethod(vm, classObj, symbol, method);
}
static int dumpInstruction(WrenVM* vm, ObjFn* fn, int i, int* lastLine)
{
int start = i;
uint8_t* bytecode = fn->code.data;
Code code = (Code)bytecode[i];
int line = fn->debug->sourceLines.data[i];
if (lastLine == NULL || *lastLine != line)
{
printf("%4d:", line);
if (lastLine != NULL) *lastLine = line;
}
else
{
printf(" ");
}
printf(" %04d ", i++);
#define READ_BYTE() (bytecode[i++])
#define READ_SHORT() (i += 2, (bytecode[i - 2] << 8) | bytecode[i - 1])
#define BYTE_INSTRUCTION(name) \
printf("%-16s %5d\n", name, READ_BYTE()); \
break; \
switch (code)
{
case CODE_CONSTANT:
{
int constant = READ_SHORT();
printf("%-16s %5d '", "CONSTANT", constant);
wrenDumpValue(fn->constants.data[constant]);
printf("'\n");
break;
}
case CODE_NULL: printf("NULL\n"); break;
case CODE_FALSE: printf("FALSE\n"); break;
case CODE_TRUE: printf("TRUE\n"); break;
case CODE_LOAD_LOCAL_0: printf("LOAD_LOCAL_0\n"); break;
case CODE_LOAD_LOCAL_1: printf("LOAD_LOCAL_1\n"); break;
case CODE_LOAD_LOCAL_2: printf("LOAD_LOCAL_2\n"); break;
case CODE_LOAD_LOCAL_3: printf("LOAD_LOCAL_3\n"); break;
case CODE_LOAD_LOCAL_4: printf("LOAD_LOCAL_4\n"); break;
case CODE_LOAD_LOCAL_5: printf("LOAD_LOCAL_5\n"); break;
case CODE_LOAD_LOCAL_6: printf("LOAD_LOCAL_6\n"); break;
case CODE_LOAD_LOCAL_7: printf("LOAD_LOCAL_7\n"); break;
case CODE_LOAD_LOCAL_8: printf("LOAD_LOCAL_8\n"); break;
case CODE_LOAD_LOCAL: BYTE_INSTRUCTION("LOAD_LOCAL");
case CODE_STORE_LOCAL: BYTE_INSTRUCTION("STORE_LOCAL");
case CODE_LOAD_UPVALUE: BYTE_INSTRUCTION("LOAD_UPVALUE");
case CODE_STORE_UPVALUE: BYTE_INSTRUCTION("STORE_UPVALUE");
case CODE_LOAD_MODULE_VAR:
{
int slot = READ_SHORT();
printf("%-16s %5d '%s'\n", "LOAD_MODULE_VAR", slot,
fn->module->variableNames.data[slot].buffer);
break;
}
case CODE_STORE_MODULE_VAR:
{
int slot = READ_SHORT();
printf("%-16s %5d '%s'\n", "STORE_MODULE_VAR", slot,
fn->module->variableNames.data[slot].buffer);
break;
}
case CODE_LOAD_FIELD_THIS: BYTE_INSTRUCTION("LOAD_FIELD_THIS");
case CODE_STORE_FIELD_THIS: BYTE_INSTRUCTION("STORE_FIELD_THIS");
case CODE_LOAD_FIELD: BYTE_INSTRUCTION("LOAD_FIELD");
case CODE_STORE_FIELD: BYTE_INSTRUCTION("STORE_FIELD");
case CODE_POP: printf("POP\n"); break;
case CODE_CALL_0:
case CODE_CALL_1:
case CODE_CALL_2:
case CODE_CALL_3:
case CODE_CALL_4:
case CODE_CALL_5:
case CODE_CALL_6:
case CODE_CALL_7:
case CODE_CALL_8:
case CODE_CALL_9:
case CODE_CALL_10:
case CODE_CALL_11:
case CODE_CALL_12:
case CODE_CALL_13:
case CODE_CALL_14:
case CODE_CALL_15:
case CODE_CALL_16:
{
int numArgs = bytecode[i - 1] - CODE_CALL_0;
int symbol = READ_SHORT();
printf("CALL_%-11d %5d '%s'\n", numArgs, symbol,
vm->methodNames.data[symbol].buffer);
break;
}
case CODE_SUPER_0:
case CODE_SUPER_1:
case CODE_SUPER_2:
case CODE_SUPER_3:
case CODE_SUPER_4:
case CODE_SUPER_5:
case CODE_SUPER_6:
case CODE_SUPER_7:
case CODE_SUPER_8:
case CODE_SUPER_9:
case CODE_SUPER_10:
case CODE_SUPER_11:
case CODE_SUPER_12:
case CODE_SUPER_13:
case CODE_SUPER_14:
case CODE_SUPER_15:
case CODE_SUPER_16:
{
int numArgs = bytecode[i - 1] - CODE_SUPER_0;
int symbol = READ_SHORT();
int superclass = READ_SHORT();
printf("SUPER_%-10d %5d '%s' %5d\n", numArgs, symbol,
vm->methodNames.data[symbol].buffer, superclass);
break;
}
case CODE_JUMP:
{
int offset = READ_SHORT();
printf("%-16s %5d to %d\n", "JUMP", offset, i + offset);
break;
}
case CODE_LOOP:
{
int offset = READ_SHORT();
printf("%-16s %5d to %d\n", "LOOP", offset, i - offset);
break;
}
case CODE_JUMP_IF:
{
int offset = READ_SHORT();
printf("%-16s %5d to %d\n", "JUMP_IF", offset, i + offset);
break;
}
case CODE_AND:
{
int offset = READ_SHORT();
printf("%-16s %5d to %d\n", "AND", offset, i + offset);
break;
}
case CODE_OR:
{
int offset = READ_SHORT();
printf("%-16s %5d to %d\n", "OR", offset, i + offset);
break;
}
case CODE_CLOSE_UPVALUE: printf("CLOSE_UPVALUE\n"); break;
case CODE_RETURN: printf("RETURN\n"); break;
case CODE_CLOSURE:
{
int constant = READ_SHORT();
printf("%-16s %5d ", "CLOSURE", constant);
wrenDumpValue(fn->constants.data[constant]);
printf(" ");
ObjFn* loadedFn = AS_FN(fn->constants.data[constant]);
for (int j = 0; j < loadedFn->numUpvalues; j++)
{
int isLocal = READ_BYTE();
int index = READ_BYTE();
if (j > 0) printf(", ");
printf("%s %d", isLocal ? "local" : "upvalue", index);
}
printf("\n");
break;
}
case CODE_CONSTRUCT: printf("CONSTRUCT\n"); break;
case CODE_FOREIGN_CONSTRUCT: printf("FOREIGN_CONSTRUCT\n"); break;
case CODE_CLASS:
{
int numFields = READ_BYTE();
printf("%-16s %5d fields\n", "CLASS", numFields);
break;
}
case CODE_FOREIGN_CLASS: printf("FOREIGN_CLASS\n"); break;
case CODE_METHOD_INSTANCE:
{
int symbol = READ_SHORT();
printf("%-16s %5d '%s'\n", "METHOD_INSTANCE", symbol,
vm->methodNames.data[symbol].buffer);
break;
}
case CODE_METHOD_STATIC:
{
int symbol = READ_SHORT();
printf("%-16s %5d '%s'\n", "METHOD_STATIC", symbol,
vm->methodNames.data[symbol].buffer);
break;
}
case CODE_IMPORT_MODULE:
{
int name = READ_SHORT();
printf("%-16s %5d '", "IMPORT_MODULE", name);
wrenDumpValue(fn->constants.data[name]);
printf("'\n");
break;
}
case CODE_IMPORT_VARIABLE:
{
int module = READ_SHORT();
int variable = READ_SHORT();
printf("%-16s %5d '", "IMPORT_VARIABLE", module);
wrenDumpValue(fn->constants.data[module]);
printf("' %5d '", variable);
wrenDumpValue(fn->constants.data[variable]);
printf("'\n");
break;
}
case CODE_END:
printf("END\n");
break;
default:
printf("UKNOWN! [%d]\n", bytecode[i - 1]);
break;
}
// Return how many bytes this instruction takes, or -1 if it's an END.
if (code == CODE_END) return -1;
return i - start;
#undef READ_BYTE
#undef READ_SHORT
}
// 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.
static bool runInterpreter(WrenVM* vm)
{
// Hoist these into local variables. They are accessed frequently in the loop
// but assigned less frequently. Keeping them in locals and updating them when
// a call frame has been pushed or popped gives a large speed boost.
register ObjFiber* fiber = vm->fiber;
register CallFrame* frame;
register Value* stackStart;
register uint8_t* ip;
register ObjFn* fn;
// These macros are designed to only be invoked within this function.
#define PUSH(value) (*fiber->stackTop++ = value)
#define POP() (*(--fiber->stackTop))
#define DROP() (fiber->stackTop--)
#define PEEK() (*(fiber->stackTop - 1))
#define PEEK2() (*(fiber->stackTop - 2))
#define READ_BYTE() (*ip++)
#define READ_SHORT() (ip += 2, (ip[-2] << 8) | ip[-1])
// Use this before a CallFrame is pushed to store the local variables back
// into the current one.
#define STORE_FRAME() frame->ip = ip
// Use this after a CallFrame has been pushed or popped to refresh the local
// variables.
#define LOAD_FRAME() \
frame = &fiber->frames[fiber->numFrames - 1]; \
stackStart = frame->stackStart; \
ip = frame->ip; \
if (frame->fn->type == OBJ_FN) \
{ \
fn = (ObjFn*)frame->fn; \
} \
else \
{ \
fn = ((ObjClosure*)frame->fn)->fn; \
}
// Terminates the current fiber with error string [error]. If another calling
// fiber is willing to catch the error, transfers control to it, otherwise
// exits the interpreter.
#define RUNTIME_ERROR(error) \
do { \
STORE_FRAME(); \
fiber = runtimeError(vm, fiber, error); \
if (fiber == NULL) return false; \
LOAD_FRAME(); \
DISPATCH(); \
} \
while (false)
#if WREN_COMPUTED_GOTO
// Note that the order of instructions here must exacly match the Code enum
// in wren_vm.h or horrendously bad things happen.
static void* dispatchTable[] = {
&&code_CONSTANT,
&&code_NULL,
&&code_FALSE,
&&code_TRUE,
&&code_LOAD_LOCAL_0,
&&code_LOAD_LOCAL_1,
&&code_LOAD_LOCAL_2,
&&code_LOAD_LOCAL_3,
&&code_LOAD_LOCAL_4,
&&code_LOAD_LOCAL_5,
&&code_LOAD_LOCAL_6,
&&code_LOAD_LOCAL_7,
&&code_LOAD_LOCAL_8,
&&code_LOAD_LOCAL,
&&code_STORE_LOCAL,
&&code_LOAD_UPVALUE,
&&code_STORE_UPVALUE,
&&code_LOAD_GLOBAL,
&&code_STORE_GLOBAL,
&&code_LOAD_FIELD_THIS,
&&code_STORE_FIELD_THIS,
&&code_LOAD_FIELD,
&&code_STORE_FIELD,
&&code_POP,
&&code_CALL_0,
&&code_CALL_1,
&&code_CALL_2,
&&code_CALL_3,
&&code_CALL_4,
&&code_CALL_5,
&&code_CALL_6,
&&code_CALL_7,
&&code_CALL_8,
&&code_CALL_9,
&&code_CALL_10,
&&code_CALL_11,
&&code_CALL_12,
&&code_CALL_13,
&&code_CALL_14,
&&code_CALL_15,
&&code_CALL_16,
&&code_SUPER_0,
&&code_SUPER_1,
&&code_SUPER_2,
&&code_SUPER_3,
&&code_SUPER_4,
&&code_SUPER_5,
&&code_SUPER_6,
&&code_SUPER_7,
&&code_SUPER_8,
&&code_SUPER_9,
&&code_SUPER_10,
&&code_SUPER_11,
&&code_SUPER_12,
&&code_SUPER_13,
&&code_SUPER_14,
&&code_SUPER_15,
&&code_SUPER_16,
&&code_JUMP,
&&code_LOOP,
&&code_JUMP_IF,
&&code_AND,
&&code_OR,
&&code_IS,
&&code_CLOSE_UPVALUE,
&&code_RETURN,
&&code_LIST,
&&code_CLOSURE,
&&code_CLASS,
&&code_METHOD_INSTANCE,
&&code_METHOD_STATIC,
&&code_END
};
#define INTERPRET_LOOP DISPATCH();
#define CASE_CODE(name) code_##name
#if WREN_DEBUG_TRACE_INSTRUCTIONS
// Prints the stack and instruction before each instruction is executed.
#define DISPATCH() \
{ \
wrenDebugPrintStack(fiber); \
wrenDebugPrintInstruction(vm, fn, (int)(ip - fn->bytecode)); \
instruction = *ip++; \
goto *dispatchTable[instruction]; \
}
#else
#define DISPATCH() goto *dispatchTable[instruction = READ_BYTE()];
#endif
#else
#define INTERPRET_LOOP for (;;) switch (instruction = READ_BYTE())
#define CASE_CODE(name) case CODE_##name
#define DISPATCH() break
#endif
LOAD_FRAME();
Code instruction;
INTERPRET_LOOP
{
CASE_CODE(LOAD_LOCAL_0):
CASE_CODE(LOAD_LOCAL_1):
CASE_CODE(LOAD_LOCAL_2):
CASE_CODE(LOAD_LOCAL_3):
CASE_CODE(LOAD_LOCAL_4):
CASE_CODE(LOAD_LOCAL_5):
CASE_CODE(LOAD_LOCAL_6):
CASE_CODE(LOAD_LOCAL_7):
CASE_CODE(LOAD_LOCAL_8):
PUSH(stackStart[instruction - CODE_LOAD_LOCAL_0]);
DISPATCH();
CASE_CODE(LOAD_LOCAL):
PUSH(stackStart[READ_BYTE()]);
DISPATCH();
CASE_CODE(LOAD_FIELD_THIS):
{
int field = READ_BYTE();
Value receiver = stackStart[0];
ASSERT(IS_INSTANCE(receiver), "Receiver should be instance.");
ObjInstance* instance = AS_INSTANCE(receiver);
ASSERT(field < instance->obj.classObj->numFields, "Out of bounds field.");
PUSH(instance->fields[field]);
DISPATCH();
}
CASE_CODE(POP): DROP(); DISPATCH();
CASE_CODE(NULL): PUSH(NULL_VAL); DISPATCH();
CASE_CODE(FALSE): PUSH(FALSE_VAL); DISPATCH();
CASE_CODE(TRUE): PUSH(TRUE_VAL); DISPATCH();
CASE_CODE(CALL_0):
CASE_CODE(CALL_1):
CASE_CODE(CALL_2):
CASE_CODE(CALL_3):
CASE_CODE(CALL_4):
CASE_CODE(CALL_5):
CASE_CODE(CALL_6):
CASE_CODE(CALL_7):
CASE_CODE(CALL_8):
CASE_CODE(CALL_9):
CASE_CODE(CALL_10):
CASE_CODE(CALL_11):
CASE_CODE(CALL_12):
CASE_CODE(CALL_13):
CASE_CODE(CALL_14):
CASE_CODE(CALL_15):
CASE_CODE(CALL_16):
{
// Add one for the implicit receiver argument.
int numArgs = instruction - CODE_CALL_0 + 1;
int symbol = READ_SHORT();
Value receiver = *(fiber->stackTop - numArgs);
ObjClass* classObj = wrenGetClassInline(vm, receiver);
// If the class's method table doesn't include the symbol, bail.
if (symbol >= classObj->methods.count)
{
RUNTIME_ERROR(methodNotFound(vm, classObj, symbol));
}
Method* method = &classObj->methods.data[symbol];
switch (method->type)
{
case METHOD_PRIMITIVE:
{
Value* args = fiber->stackTop - numArgs;
// After calling this, the result will be in the first arg slot.
switch (method->fn.primitive(vm, fiber, args))
{
case PRIM_VALUE:
// The result is now in the first arg slot. Discard the other
// stack slots.
fiber->stackTop -= numArgs - 1;
break;
case PRIM_ERROR:
RUNTIME_ERROR(AS_STRING(args[0]));
case PRIM_CALL:
STORE_FRAME();
callFunction(fiber, AS_OBJ(args[0]), numArgs);
LOAD_FRAME();
break;
case PRIM_RUN_FIBER:
STORE_FRAME();
fiber = AS_FIBER(args[0]);
LOAD_FRAME();
break;
}
break;
}
case METHOD_FOREIGN:
callForeign(vm, fiber, method->fn.foreign, numArgs);
break;
case METHOD_BLOCK:
STORE_FRAME();
callFunction(fiber, method->fn.obj, numArgs);
LOAD_FRAME();
break;
case METHOD_NONE:
RUNTIME_ERROR(methodNotFound(vm, classObj, symbol));
break;
}
DISPATCH();
}
CASE_CODE(STORE_LOCAL):
stackStart[READ_BYTE()] = PEEK();
DISPATCH();
CASE_CODE(CONSTANT):
PUSH(fn->constants[READ_SHORT()]);
DISPATCH();
CASE_CODE(SUPER_0):
CASE_CODE(SUPER_1):
CASE_CODE(SUPER_2):
CASE_CODE(SUPER_3):
CASE_CODE(SUPER_4):
CASE_CODE(SUPER_5):
CASE_CODE(SUPER_6):
CASE_CODE(SUPER_7):
CASE_CODE(SUPER_8):
CASE_CODE(SUPER_9):
CASE_CODE(SUPER_10):
CASE_CODE(SUPER_11):
CASE_CODE(SUPER_12):
CASE_CODE(SUPER_13):
CASE_CODE(SUPER_14):
CASE_CODE(SUPER_15):
CASE_CODE(SUPER_16):
{
// TODO: Almost completely copied from CALL. Unify somehow.
// Add one for the implicit receiver argument.
int numArgs = instruction - CODE_SUPER_0 + 1;
int symbol = READ_SHORT();
Value receiver = *(fiber->stackTop - numArgs);
ObjClass* classObj = wrenGetClassInline(vm, receiver);
// Ignore methods defined on the receiver's immediate class.
classObj = classObj->superclass;
// If the class's method table doesn't include the symbol, bail.
if (symbol >= classObj->methods.count)
{
RUNTIME_ERROR(methodNotFound(vm, classObj, symbol));
}
Method* method = &classObj->methods.data[symbol];
switch (method->type)
{
case METHOD_PRIMITIVE:
{
Value* args = fiber->stackTop - numArgs;
// After calling this, the result will be in the first arg slot.
switch (method->fn.primitive(vm, fiber, args))
{
case PRIM_VALUE:
// The result is now in the first arg slot. Discard the other
// stack slots.
fiber->stackTop -= numArgs - 1;
break;
case PRIM_ERROR:
RUNTIME_ERROR(AS_STRING(args[0]));
case PRIM_CALL:
STORE_FRAME();
callFunction(fiber, AS_OBJ(args[0]), numArgs);
LOAD_FRAME();
break;
case PRIM_RUN_FIBER:
STORE_FRAME();
fiber = AS_FIBER(args[0]);
LOAD_FRAME();
break;
}
break;
}
case METHOD_FOREIGN:
callForeign(vm, fiber, method->fn.foreign, numArgs);
break;
case METHOD_BLOCK:
STORE_FRAME();
callFunction(fiber, method->fn.obj, numArgs);
LOAD_FRAME();
break;
case METHOD_NONE:
RUNTIME_ERROR(methodNotFound(vm, classObj, symbol));
break;
}
DISPATCH();
}
CASE_CODE(LOAD_UPVALUE):
{
Upvalue** upvalues = ((ObjClosure*)frame->fn)->upvalues;
PUSH(*upvalues[READ_BYTE()]->value);
DISPATCH();
}
CASE_CODE(STORE_UPVALUE):
{
Upvalue** upvalues = ((ObjClosure*)frame->fn)->upvalues;
*upvalues[READ_BYTE()]->value = PEEK();
DISPATCH();
}
CASE_CODE(LOAD_GLOBAL):
PUSH(vm->globals.data[READ_SHORT()]);
DISPATCH();
CASE_CODE(STORE_GLOBAL):
vm->globals.data[READ_SHORT()] = PEEK();
DISPATCH();
CASE_CODE(STORE_FIELD_THIS):
{
int field = READ_BYTE();
Value receiver = stackStart[0];
ASSERT(IS_INSTANCE(receiver), "Receiver should be instance.");
ObjInstance* instance = AS_INSTANCE(receiver);
ASSERT(field < instance->obj.classObj->numFields, "Out of bounds field.");
instance->fields[field] = PEEK();
DISPATCH();
}
CASE_CODE(LOAD_FIELD):
{
int field = READ_BYTE();
Value receiver = POP();
ASSERT(IS_INSTANCE(receiver), "Receiver should be instance.");
ObjInstance* instance = AS_INSTANCE(receiver);
ASSERT(field < instance->obj.classObj->numFields, "Out of bounds field.");
PUSH(instance->fields[field]);
DISPATCH();
}
CASE_CODE(STORE_FIELD):
{
int field = READ_BYTE();
Value receiver = POP();
ASSERT(IS_INSTANCE(receiver), "Receiver should be instance.");
ObjInstance* instance = AS_INSTANCE(receiver);
ASSERT(field < instance->obj.classObj->numFields, "Out of bounds field.");
instance->fields[field] = PEEK();
DISPATCH();
}
CASE_CODE(JUMP):
{
int offset = READ_SHORT();
ip += offset;
DISPATCH();
}
CASE_CODE(LOOP):
{
// Jump back to the top of the loop.
int offset = READ_SHORT();
ip -= offset;
DISPATCH();
}
CASE_CODE(JUMP_IF):
{
int offset = READ_SHORT();
Value condition = POP();
if (IS_FALSE(condition) || IS_NULL(condition)) ip += offset;
DISPATCH();
}
CASE_CODE(AND):
{
int offset = READ_SHORT();
Value condition = PEEK();
if (IS_FALSE(condition) || IS_NULL(condition))
{
// Short-circuit the right hand side.
ip += offset;
}
else
{
// Discard the condition and evaluate the right hand side.
DROP();
}
DISPATCH();
}
CASE_CODE(OR):
{
int offset = READ_SHORT();
Value condition = PEEK();
if (IS_FALSE(condition) || IS_NULL(condition))
{
// Discard the condition and evaluate the right hand side.
DROP();
}
else
{
// Short-circuit the right hand side.
ip += offset;
}
DISPATCH();
}
CASE_CODE(IS):
{
Value expected = POP();
if (!IS_CLASS(expected))
{
const char* message = "Right operand must be a class.";
RUNTIME_ERROR(AS_STRING(wrenNewString(vm, message, strlen(message))));
}
ObjClass* actual = wrenGetClass(vm, POP());
bool isInstance = false;
// Walk the superclass chain looking for the class.
while (actual != NULL)
{
if (actual == AS_CLASS(expected))
{
isInstance = true;
break;
}
actual = actual->superclass;
}
PUSH(BOOL_VAL(isInstance));
DISPATCH();
}
CASE_CODE(CLOSE_UPVALUE):
closeUpvalue(fiber);
DROP();
DISPATCH();
CASE_CODE(RETURN):
{
Value result = POP();
fiber->numFrames--;
// Close any upvalues still in scope.
Value* firstValue = stackStart;
while (fiber->openUpvalues != NULL &&
fiber->openUpvalues->value >= firstValue)
{
closeUpvalue(fiber);
}
// 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;
// Store the result in the resuming fiber.
*(fiber->stackTop - 1) = result;
}
else
{
// Store the result of the block in the first slot, which is where the
// caller expects it.
stackStart[0] = result;
// Discard the stack slots for the call frame (leaving one slot for the
// result).
fiber->stackTop = frame->stackStart + 1;
}
LOAD_FRAME();
DISPATCH();
}
CASE_CODE(LIST):
{
int numElements = READ_BYTE();
ObjList* list = wrenNewList(vm, numElements);
// TODO: Do a straight memcopy.
for (int i = 0; i < numElements; i++)
{
list->elements[i] = *(fiber->stackTop - numElements + i);
}
// Discard the elements.
fiber->stackTop -= numElements;
PUSH(OBJ_VAL(list));
DISPATCH();
}
CASE_CODE(CLOSURE):
{
ObjFn* prototype = AS_FN(fn->constants[READ_SHORT()]);
ASSERT(prototype->numUpvalues > 0,
"Should not create closure for functions that don't need it.");
// Create the closure and push it on the stack before creating upvalues
// so that it doesn't get collected.
ObjClosure* closure = wrenNewClosure(vm, prototype);
PUSH(OBJ_VAL(closure));
// Capture upvalues.
for (int i = 0; i < prototype->numUpvalues; i++)
{
bool isLocal = READ_BYTE();
int index = READ_BYTE();
if (isLocal)
{
// Make an new upvalue to close over the parent's local variable.
closure->upvalues[i] = captureUpvalue(vm, fiber,
frame->stackStart + index);
}
else
{
// Use the same upvalue as the current call frame.
closure->upvalues[i] = ((ObjClosure*)frame->fn)->upvalues[index];
}
}
DISPATCH();
}
CASE_CODE(CLASS):
{
ObjString* name = AS_STRING(PEEK2());
ObjClass* superclass;
if (IS_NULL(PEEK()))
{
// Implicit Object superclass.
superclass = vm->objectClass;
}
else
{
// TODO: Handle the superclass not being a class object!
superclass = AS_CLASS(PEEK());
}
int numFields = READ_BYTE();
ObjClass* classObj = wrenNewClass(vm, superclass, numFields, name);
// 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.
DROP();
DROP();
// Now that we know the total number of fields, make sure we don't
// overflow.
if (superclass->numFields + numFields > MAX_FIELDS)
{
char message[70 + MAX_VARIABLE_NAME];
snprintf(message, 70 + MAX_VARIABLE_NAME,
"Class '%s' may not have more than %d fields, including inherited "
"ones.", name->value, MAX_FIELDS);
RUNTIME_ERROR(AS_STRING(wrenNewString(vm, message, strlen(message))));
}
PUSH(OBJ_VAL(classObj));
DISPATCH();
}
CASE_CODE(METHOD_INSTANCE):
CASE_CODE(METHOD_STATIC):
{
int type = instruction;
int symbol = READ_SHORT();
ObjClass* classObj = AS_CLASS(PEEK());
Value method = PEEK2();
bindMethod(vm, type, symbol, classObj, method);
DROP();
DROP();
DISPATCH();
}
CASE_CODE(END):
// A CODE_END should always be preceded by a CODE_RETURN. If we get here,
// the compiler generated wrong code.
UNREACHABLE();
}
// We should only exit this function from an explicit return from CODE_RETURN
// or a runtime error.
UNREACHABLE();
return false;
}
WrenInterpretResult wrenInterpret(WrenVM* vm, const char* sourcePath,
const char* source)
{
// TODO: Check for freed VM.
ObjFn* fn = wrenCompile(vm, sourcePath, source);
if (fn == NULL) return WREN_RESULT_COMPILE_ERROR;
WREN_PIN(vm, fn);
vm->fiber = wrenNewFiber(vm, (Obj*)fn);
WREN_UNPIN(vm);
if (runInterpreter(vm))
{
return WREN_RESULT_SUCCESS;
}
else
{
return WREN_RESULT_RUNTIME_ERROR;
}
}
