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janet/core/vm.c

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/*
* Copyright (c) 2017 Calvin Rose
*
* 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 <gst/gst.h>
static const char GST_NO_UPVALUE[] = "no upvalue";
static const char GST_EXPECTED_FUNCTION[] = "expected function";
/* Start running the VM from where it left off. */
int gst_continue(Gst *vm) {
/* VM state */
GstValue *stack;
uint16_t *pc;
/* Some temporary values */
GstValue temp, v1, v2;
#define gst_exit(vm, r) return ((vm)->ret = (r), GST_RETURN_OK)
#define gst_error(vm, e) do { (vm)->ret = gst_string_cv((vm), (e)); goto vm_error; } while (0)
#define gst_assert(vm, cond, e) do {if (!(cond)){gst_error((vm), (e));}} while (0)
/* Intialize local state */
vm->thread->status = GST_THREAD_ALIVE;
stack = gst_thread_stack(vm->thread);
pc = gst_frame_pc(stack);
/* Main interpreter loop */
for (;;) {
switch (*pc) {
default:
gst_error(vm, "unknown opcode");
break;
case GST_OP_FLS: /* Load False */
temp.type = GST_BOOLEAN;
temp.data.boolean = 0;
stack[pc[1]] = temp;
pc += 2;
continue;
case GST_OP_TRU: /* Load True */
temp.type = GST_BOOLEAN;
temp.data.boolean = 1;
stack[pc[1]] = temp;
pc += 2;
continue;
case GST_OP_NIL: /* Load Nil */
temp.type = GST_NIL;
stack[pc[1]] = temp;
pc += 2;
continue;
case GST_OP_I16: /* Load Small Integer */
temp.type = GST_INTEGER;
temp.data.integer = ((int16_t *)(pc))[2];
stack[pc[1]] = temp;
pc += 3;
continue;
case GST_OP_UPV: /* Load Up Value */
case GST_OP_SUV: /* Set Up Value */
{
GstValue *upv;
GstFunction *fn;
GstFuncEnv *env;
uint16_t level = pc[2];
temp = gst_frame_callee(stack);
gst_assert(vm, temp.type == GST_FUNCTION, GST_EXPECTED_FUNCTION);
fn = temp.data.function;
if (level == 0)
upv = stack + pc[3];
else {
while (fn && --level)
fn = fn->parent;
gst_assert(vm, fn, GST_NO_UPVALUE);
env = fn->env;
if (env->thread)
upv = env->thread->data + env->stackOffset + pc[3];
else
upv = env->values + pc[3];
}
if (pc[0] == GST_OP_UPV) {
stack[pc[1]] = *upv;
} else {
*upv = stack[pc[1]];
}
pc += 4;
}
continue;
case GST_OP_JIF: /* Jump If */
if (gst_truthy(stack[pc[1]])) {
pc += 4;
} else {
pc += *((int32_t *)(pc + 2));
}
continue;
case GST_OP_JMP: /* Jump */
pc += *((int32_t *)(pc + 1));
continue;
case GST_OP_CST: /* Load constant value */
v1 = gst_frame_callee(stack);
gst_assert(vm, v1.type == GST_FUNCTION, GST_EXPECTED_FUNCTION);
if (pc[2] > v1.data.function->def->literalsLen)
gst_error(vm, GST_NO_UPVALUE);
stack[pc[1]] = v1.data.function->def->literals[pc[2]];
pc += 3;
continue;
case GST_OP_I32: /* Load 32 bit integer */
temp.type = GST_INTEGER;
temp.data.integer = *((int32_t *)(pc + 2));
stack[pc[1]] = temp;
pc += 4;
continue;
case GST_OP_I64: /* Load 64 bit integer */
temp.type = GST_INTEGER;
temp.data.integer = (GstInteger) *((int64_t *)(pc + 2));
stack[pc[1]] = temp;
pc += 6;
continue;
case GST_OP_F64: /* Load 64 bit float */
temp.type = GST_REAL;
temp.data.real = (GstReal) *((double *)(pc + 2));
stack[pc[1]] = temp;
pc += 6;
continue;
case GST_OP_MOV: /* Move Values */
stack[pc[1]] = stack[pc[2]];
pc += 3;
continue;
case GST_OP_CLN: /* Create closure from constant FuncDef */
{
GstFunction *fn;
v1 = gst_frame_callee(stack);
temp = v1.data.function->def->literals[pc[2]];
if (temp.type != GST_FUNCDEF)
gst_error(vm, "cannot create closure from non-funcdef");
fn = gst_alloc(vm, sizeof(GstFunction));
fn->def = temp.data.def;
if (temp.data.def->flags & GST_FUNCDEF_FLAG_NEEDSPARENT)
fn->parent = v1.data.function;
else
fn->parent = NULL;
if (v1.type != GST_FUNCTION)
gst_error(vm, GST_EXPECTED_FUNCTION);
if (gst_frame_env(stack) == NULL && (fn->def->flags & GST_FUNCDEF_FLAG_NEEDSENV)) {
gst_frame_env(stack) = gst_alloc(vm, sizeof(GstFuncEnv));
gst_frame_env(stack)->thread = vm->thread;
gst_frame_env(stack)->stackOffset = vm->thread->count;
gst_frame_env(stack)->values = NULL;
}
if (pc[2] > v1.data.function->def->literalsLen)
gst_error(vm, GST_NO_UPVALUE);
if (fn->def->flags & GST_FUNCDEF_FLAG_NEEDSENV)
fn->env = gst_frame_env(stack);
else
fn->env = NULL;
temp.type = GST_FUNCTION;
temp.data.function = fn;
stack[pc[1]] = temp;
pc += 3;
}
break;
case GST_OP_RTN: /* Return nil */
temp.type = GST_NIL;
goto vm_return;
case GST_OP_RET: /* Return */
temp = stack[pc[1]];
goto vm_return;
case GST_OP_PSK: /* Push stack */
{
uint16_t arity = pc[1];
uint16_t i;
uint16_t newBase = gst_frame_size(stack) + GST_FRAME_SIZE;
gst_frame_args(stack) = newBase;
gst_thread_ensure_extra(vm, vm->thread, GST_FRAME_SIZE + arity);
stack = gst_thread_stack(vm->thread);
gst_frame_size(stack) += GST_FRAME_SIZE + arity;
/* Nil stuff */
for (i = 0; i < GST_FRAME_SIZE; ++i)
stack[newBase + i - GST_FRAME_SIZE].type = GST_NIL;
/* Write arguments */
for (i = 0; i < arity; ++i)
stack[newBase + i] = stack[pc[2 + i]];
pc += 2 + arity;
}
break;
case GST_OP_PAR: /* Push array or tuple */
{
uint32_t count, i, oldsize;
const GstValue *data;
temp = stack[pc[1]];
if (temp.type == GST_TUPLE) {
count = gst_tuple_length(temp.data.tuple);
data = temp.data.tuple;
} else if (temp.type == GST_ARRAY){
count = temp.data.array->count;
data = temp.data.array->data;
} else {
gst_error(vm, "expected array or tuple");
}
oldsize = gst_frame_size(stack);
gst_thread_pushnil(vm, vm->thread, count);
stack = gst_thread_stack(vm->thread);
for (i = 0; i < count; ++i)
stack[oldsize + i] = data[i];
/*gst_frame_size(stack) += count;*/
pc += 2;
}
break;
case GST_OP_CAL: /* Call */
{
uint16_t newStackIndex = gst_frame_args(stack);
uint16_t size = gst_frame_size(stack);
temp = stack[pc[1]];
gst_frame_size(stack) = newStackIndex - GST_FRAME_SIZE;
gst_frame_ret(stack) = pc[2];
gst_frame_pc(stack) = pc + 3;
if (newStackIndex < GST_FRAME_SIZE)
gst_error(vm, "invalid call instruction");
vm->thread->count += newStackIndex;
stack = gst_thread_stack(vm->thread);
gst_frame_size(stack) = size - newStackIndex;
gst_frame_prevsize(stack) = newStackIndex - GST_FRAME_SIZE;
gst_frame_callee(stack) = temp;
}
goto common_function_call;
case GST_OP_TCL: /* Tail call */
{
uint16_t newStackIndex = gst_frame_args(stack);
uint16_t size = gst_frame_size(stack);
uint16_t i;
temp = stack[pc[1]];
/* Check for closures */
if (gst_frame_env(stack)) {
GstFuncEnv *env = gst_frame_env(stack);
env->thread = NULL;
env->stackOffset = size;
env->values = gst_alloc(vm, sizeof(GstValue) * size);
gst_memcpy(env->values, stack, sizeof(GstValue) * size);
}
if (newStackIndex)
for (i = 0; i < size - newStackIndex; ++i)
stack[i] = stack[newStackIndex + i];
gst_frame_size(stack) = size - newStackIndex;
gst_frame_callee(stack) = temp;
}
goto common_function_call;
/* Code common to all function calls */
common_function_call:
gst_frame_args(stack) = 0;
gst_frame_env(stack) = NULL;
gst_thread_endframe(vm, vm->thread);
stack = vm->thread->data + vm->thread->count;
temp = gst_frame_callee(stack);
if (temp.type == GST_FUNCTION) {
pc = temp.data.function->def->byteCode;
} else if (temp.type == GST_CFUNCTION) {
int status;
vm->ret.type = GST_NIL;
status = temp.data.cfunction(vm);
if (status == GST_RETURN_OK) {
temp = vm->ret;
goto vm_return;
} else {
goto vm_error;
}
} else {
gst_error(vm, GST_EXPECTED_FUNCTION);
}
break;
case GST_OP_ARR: /* Array literal */
{
uint32_t i;
uint32_t arrayLen = pc[2];
GstArray *array = gst_array(vm, arrayLen);
array->count = arrayLen;
for (i = 0; i < arrayLen; ++i)
array->data[i] = stack[pc[3 + i]];
temp.type = GST_ARRAY;
temp.data.array = array;
stack[pc[1]] = temp;
pc += 3 + arrayLen;
}
break;
case GST_OP_DIC: /* Table literal */
{
uint32_t i = 3;
uint32_t kvs = pc[2];
GstTable *t = gst_table(vm, 2 * kvs);
kvs = kvs + 3;
while (i < kvs) {
v1 = stack[pc[i++]];
v2 = stack[pc[i++]];
gst_table_put(vm, t, v1, v2);
}
temp.type = GST_TABLE;
temp.data.table = t;
stack[pc[1]] = temp;
pc += kvs;
}
break;
case GST_OP_TUP: /* Tuple literal */
{
uint32_t i;
uint32_t len = pc[2];
GstValue *tuple = gst_tuple_begin(vm, len);
for (i = 0; i < len; ++i)
tuple[i] = stack[pc[3 + i]];
temp.type = GST_TUPLE;
temp.data.tuple = gst_tuple_end(vm, tuple);
stack[pc[1]] = temp;
pc += 3 + len;
}
break;
case GST_OP_TRN: /* Transfer */
temp = stack[pc[2]]; /* The thread */
v1 = stack[pc[3]]; /* The value to pass in */
if (temp.type != GST_THREAD && temp.type != GST_NIL)
gst_error(vm, "expected thread");
if (temp.type == GST_NIL && vm->thread->parent) {
temp = gst_wrap_thread(vm->thread->parent);
}
if (temp.type == GST_THREAD) {
if (temp.data.thread->status != GST_THREAD_PENDING)
gst_error(vm, "can only enter pending thread");
}
gst_frame_ret(stack) = pc[1];
vm->thread->status = GST_THREAD_PENDING;
gst_frame_pc(stack) = pc + 4;
if (temp.type == GST_NIL) {
vm->ret = v1;
return GST_RETURN_OK;
}
temp.data.thread->status = GST_THREAD_ALIVE;
vm->thread = temp.data.thread;
stack = gst_thread_stack(temp.data.thread);
if (gst_frame_callee(stack).type != GST_FUNCTION)
goto vm_return;
stack[gst_frame_ret(stack)] = v1;
pc = gst_frame_pc(stack);
continue;
/* Handle returning from stack frame. Expect return value in temp. */
vm_return:
stack = gst_thread_popframe(vm, vm->thread);
while (vm->thread->count < GST_FRAME_SIZE ||
vm->thread->status == GST_THREAD_DEAD ||
vm->thread->status == GST_THREAD_ERROR) {
vm->thread->status = GST_THREAD_DEAD;
if (vm->thread->parent) {
vm->thread = vm->thread->parent;
if (vm->thread->status == GST_THREAD_ALIVE) {
/* If the parent thread is still alive,
we are inside a cfunction */
vm->ret = temp;
return GST_RETURN_OK;
}
stack = vm->thread->data + vm->thread->count;
} else {
vm->ret = temp;
return GST_RETURN_OK;
}
}
vm->thread->status = GST_THREAD_ALIVE;
pc = gst_frame_pc(stack);
stack[gst_frame_ret(stack)] = temp;
continue;
/* Handle errors from c functions and vm opcodes */
vm_error:
vm->thread->status = GST_THREAD_ERROR;
while (vm->thread->count < GST_FRAME_SIZE ||
vm->thread->status == GST_THREAD_DEAD ||
vm->thread->status == GST_THREAD_ERROR) {
if (vm->thread->errorParent == NULL)
return GST_RETURN_ERROR;
vm->thread = vm->thread->errorParent;
if (vm->thread->status == GST_THREAD_ALIVE) {
/* If the parent thread is still alive,
we are inside a cfunction */
return GST_RETURN_ERROR;
}
}
vm->thread->status = GST_THREAD_ALIVE;
stack = vm->thread->data + vm->thread->count;
stack[gst_frame_ret(stack)] = vm->ret;
pc = gst_frame_pc(stack);
continue;
} /* end switch */
/* Check for collection every cycle. If the instruction definitely does
* not allocate memory, it can use continue instead of break to
* skip this check */
gst_maybe_collect(vm);
} /* end for */
}
/* Run the vm with a given function. This function is
* called to start the vm. */
int gst_run(Gst *vm, GstValue callee) {
int result;
if (vm->thread &&
(vm->thread->status == GST_THREAD_DEAD ||
vm->thread->status == GST_THREAD_ALIVE)) {
/* Reuse old thread */
gst_thread_reset(vm, vm->thread, callee);
} else {
/* Create new thread */
vm->thread = gst_thread(vm, callee, 64);
}
if (callee.type == GST_CFUNCTION) {
vm->ret.type = GST_NIL;
result = callee.data.cfunction(vm);
} else if (callee.type == GST_FUNCTION) {
result = gst_continue(vm);
} else {
vm->ret = gst_string_cv(vm, "expected function");
return GST_RETURN_ERROR;
}
/* Handle yields */
while (result == GST_RETURN_OK && vm->thread->status == GST_THREAD_PENDING) {
/* Send back in the value yielded - TODO - do something useful with this */
GstValue *stack = gst_thread_stack(vm->thread);
stack[gst_frame_ret(stack)] = vm->ret;
/* Resume */
result = gst_continue(vm);
}
return result;
}
/* Get an argument from the stack */
GstValue gst_arg(Gst *vm, uint32_t index) {
GstValue *stack = gst_thread_stack(vm->thread);
uint32_t frameSize = gst_frame_size(stack);
if (frameSize <= index) {
GstValue ret;
ret.type = GST_NIL;
return ret;
}
return stack[index];
}
/* Put a value on the stack */
void gst_set_arg(Gst* vm, uint32_t index, GstValue x) {
GstValue *stack = gst_thread_stack(vm->thread);
uint32_t frameSize = gst_frame_size(stack);
if (frameSize <= index) return;
stack[index] = x;
}
/* Get the size of the VMStack */
uint32_t gst_count_args(Gst *vm) {
GstValue *stack = gst_thread_stack(vm->thread);
return gst_frame_size(stack);
}
/* Initialize the VM */
void gst_init(Gst *vm) {
vm->ret.type = GST_NIL;
/* Garbage collection */
vm->blocks = NULL;
vm->nextCollection = 0;
/* Setting memoryInterval to zero forces
* a collection pretty much every cycle, which is
* horrible for performance, but helps ensure
* there are no memory bugs during dev */
vm->memoryInterval = 0;
vm->black = 0;
/* Add thread */
vm->thread = NULL;
/* Set up the cache */
vm->cache = gst_raw_calloc(1, 128 * sizeof(GstValue));
vm->cache_capacity = vm->cache == NULL ? 0 : 128;
vm->cache_count = 0;
vm->cache_deleted = 0;
/* Set up global env */
vm->modules = gst_table(vm, 10);
vm->registry = gst_table(vm, 10);
vm->env = gst_table(vm, 10);
}
/* Clear all memory associated with the VM */
void gst_deinit(Gst *vm) {
gst_clear_memory(vm);
vm->thread = NULL;
vm->modules = NULL;
vm->registry = NULL;
vm->ret.type = GST_NIL;
/* Deinit the cache */
gst_raw_free(vm->cache);
vm->cache = NULL;
vm->cache_count = 0;
vm->cache_capacity = 0;
vm->cache_deleted = 0;
}
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