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janet/src/core/vm.c

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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 <dst/dst.h>
#include <dst/dstopcodes.h>
#include "symcache.h"
#include "gc.h"
/* VM State */
DstFiber *dst_vm_fiber = NULL;
int dst_vm_stackn = 0;
/* Helper to ensure proper fiber is activated after returning */
static int dst_update_fiber(uint32_t mask) {
if (dst_vm_fiber->frame == 0) {
dst_vm_fiber->status = DST_FIBER_DEAD;
}
while (dst_vm_fiber->status == DST_FIBER_DEAD ||
dst_vm_fiber->status == DST_FIBER_ERROR ||
dst_vm_fiber->status == DST_FIBER_DEBUG ||
dst_vm_fiber->flags & mask) {
if (NULL != dst_vm_fiber->parent) {
dst_vm_fiber = dst_vm_fiber->parent;
} else {
/* The root thread has terminated */
return 1;
}
}
dst_vm_fiber->status = DST_FIBER_ALIVE;
return 0;
}
/* Start running the VM from where it left off. */
static int dst_continue(Dst *returnreg) {
/* VM state */
register Dst *stack;
register uint32_t *pc;
register DstFunction *func;
/* Keep in mind the garbage collector cannot see this value.
* Values stored here should be used immediately */
Dst retreg;
/* Increment the stackn */
if (dst_vm_stackn >= DST_RECURSION_GUARD) {
*returnreg = dst_cstringv("C stack recursed too deeply");
return 1;
}
dst_vm_stackn++;
/* Use computed gotos for GCC and clang, otherwise use switch */
#ifdef __GNUC__
#define VM_START() {vm_next();
#define VM_END() }
#define VM_OP(op) label_##op :
#define VM_DEFAULT() label_unknown_op:
#define vm_next() goto *op_lookup[*pc & 0xFF];
static void *op_lookup[255] = {
&&label_DOP_NOOP,
&&label_DOP_ERROR,
&&label_DOP_TYPECHECK,
&&label_DOP_RETURN,
&&label_DOP_RETURN_NIL,
&&label_DOP_ADD_INTEGER,
&&label_DOP_ADD_IMMEDIATE,
&&label_DOP_ADD_REAL,
&&label_DOP_ADD,
&&label_DOP_SUBTRACT_INTEGER,
&&label_DOP_SUBTRACT_REAL,
&&label_DOP_SUBTRACT,
&&label_DOP_MULTIPLY_INTEGER,
&&label_DOP_MULTIPLY_IMMEDIATE,
&&label_DOP_MULTIPLY_REAL,
&&label_DOP_MULTIPLY,
&&label_DOP_DIVIDE_INTEGER,
&&label_DOP_DIVIDE_IMMEDIATE,
&&label_DOP_DIVIDE_REAL,
&&label_DOP_DIVIDE,
&&label_DOP_BAND,
&&label_DOP_BOR,
&&label_DOP_BXOR,
&&label_DOP_BNOT,
&&label_DOP_SHIFT_LEFT,
&&label_DOP_SHIFT_LEFT_IMMEDIATE,
&&label_DOP_SHIFT_RIGHT,
&&label_DOP_SHIFT_RIGHT_IMMEDIATE,
&&label_DOP_SHIFT_RIGHT_UNSIGNED,
&&label_DOP_SHIFT_RIGHT_UNSIGNED_IMMEDIATE,
&&label_DOP_MOVE_FAR,
&&label_DOP_MOVE_NEAR,
&&label_DOP_JUMP,
&&label_DOP_JUMP_IF,
&&label_DOP_JUMP_IF_NOT,
&&label_DOP_GREATER_THAN,
&&label_DOP_LESS_THAN,
&&label_DOP_EQUALS,
&&label_DOP_COMPARE,
&&label_DOP_LOAD_NIL,
&&label_DOP_LOAD_TRUE,
&&label_DOP_LOAD_FALSE,
&&label_DOP_LOAD_INTEGER,
&&label_DOP_LOAD_CONSTANT,
&&label_DOP_LOAD_UPVALUE,
&&label_DOP_LOAD_SELF,
&&label_DOP_SET_UPVALUE,
&&label_DOP_CLOSURE,
&&label_DOP_PUSH,
&&label_DOP_PUSH_2,
&&label_DOP_PUSH_3,
&&label_DOP_PUSH_ARRAY,
&&label_DOP_CALL,
&&label_DOP_TAILCALL,
&&label_DOP_TRANSFER,
&&label_DOP_GET,
&&label_DOP_PUT,
&&label_DOP_GET_INDEX,
&&label_DOP_PUT_INDEX,
&&label_DOP_LENGTH,
&&label_DOP_DEBUG,
&&label_unknown_op
};
#else
#define VM_START() for(;;){switch(*pc & 0xFF){
#define VM_END() }}
#define VM_OP(op) case op :
#define VM_DEFAULT() default:
#define vm_next() continue
#endif
#define vm_checkgc_next() dst_maybe_collect(); vm_next()
/* Used to extract bits from the opcode that correspond to arguments.
* Pulls out unsigned integers */
#define oparg(shift, mask) (((*pc) >> ((shift) << 3)) & (mask))
#define vm_throw(e) do { retreg = dst_cstringv(e); goto vm_error; } while (0)
#define vm_assert(cond, e) do {if (!(cond)) vm_throw((e)); } while (0)
#define vm_binop_integer(op) \
stack[oparg(1, 0xFF)] = dst_wrap_integer(\
dst_unwrap_integer(stack[oparg(2, 0xFF)]) op dst_unwrap_integer(stack[oparg(3, 0xFF)])\
);\
pc++;\
vm_next();
#define vm_binop_real(op)\
stack[oparg(1, 0xFF)] = dst_wrap_real(\
dst_unwrap_real(stack[oparg(2, 0xFF)]) op dst_unwrap_real(stack[oparg(3, 0xFF)])\
);\
pc++;\
vm_next();
#define vm_binop_immediate(op)\
stack[oparg(1, 0xFF)] = dst_wrap_integer(\
dst_unwrap_integer(stack[oparg(2, 0xFF)]) op (*((int32_t *)pc) >> 24)\
);\
pc++;\
vm_next();
#define vm_binop(op)\
{\
Dst op1 = stack[oparg(2, 0xFF)];\
Dst op2 = stack[oparg(3, 0xFF)];\
vm_assert(dst_checktype(op1, DST_INTEGER) || dst_checktype(op1, DST_REAL), "expected number");\
vm_assert(dst_checktype(op2, DST_INTEGER) || dst_checktype(op2, DST_REAL), "expected number");\
stack[oparg(1, 0xFF)] = dst_checktype(op1, DST_INTEGER)\
? (dst_checktype(op2, DST_INTEGER)\
? dst_wrap_integer(dst_unwrap_integer(op1) op dst_unwrap_integer(op2))\
: dst_wrap_real((double)dst_unwrap_integer(op1) op dst_unwrap_real(op2)))\
: (dst_checktype(op2, DST_INTEGER)\
? dst_wrap_real(dst_unwrap_real(op1) op (double)dst_unwrap_integer(op2))\
: dst_wrap_real(dst_unwrap_real(op1) op dst_unwrap_real(op2)));\
pc++;\
vm_next();\
}
#define vm_init_fiber_state() \
dst_vm_fiber->status = DST_FIBER_ALIVE;\
stack = dst_vm_fiber->data + dst_vm_fiber->frame;\
pc = dst_stack_frame(stack)->pc;\
func = dst_stack_frame(stack)->func;
vm_init_fiber_state();
/* Main interpreter loop. Sematically is a switch on
* (*pc & 0xFF) inside of an infinte loop. */
VM_START();
VM_DEFAULT();
VM_OP(DOP_DEBUG)
goto vm_debug;
VM_OP(DOP_NOOP)
pc++;
vm_next();
VM_OP(DOP_ERROR)
retreg = stack[oparg(1, 0xFF)];
goto vm_error;
VM_OP(DOP_TYPECHECK)
vm_assert((1 << dst_type(stack[oparg(1, 0xFF)])) & oparg(2, 0xFFFF), "typecheck failed");
pc++;
vm_next();
VM_OP(DOP_RETURN)
retreg = stack[oparg(1, 0xFFFFFF)];
goto vm_return;
VM_OP(DOP_RETURN_NIL)
retreg = dst_wrap_nil();
goto vm_return;
VM_OP(DOP_ADD_INTEGER)
vm_binop_integer(+);
VM_OP(DOP_ADD_IMMEDIATE)
vm_binop_immediate(+);
VM_OP(DOP_ADD_REAL)
vm_binop_real(+);
VM_OP(DOP_ADD)
vm_binop(+);
VM_OP(DOP_SUBTRACT_INTEGER)
vm_binop_integer(-);
VM_OP(DOP_SUBTRACT_REAL)
vm_binop_real(-);
VM_OP(DOP_SUBTRACT)
vm_binop(-);
VM_OP(DOP_MULTIPLY_INTEGER)
vm_binop_integer(*);
VM_OP(DOP_MULTIPLY_IMMEDIATE)
vm_binop_immediate(*);
VM_OP(DOP_MULTIPLY_REAL)
vm_binop_real(*);
VM_OP(DOP_MULTIPLY)
vm_binop(*);
VM_OP(DOP_DIVIDE_INTEGER)
vm_assert(dst_unwrap_integer(stack[oparg(3, 0xFF)]) != 0, "integer divide error");
vm_assert(!(dst_unwrap_integer(stack[oparg(3, 0xFF)]) == -1 &&
dst_unwrap_integer(stack[oparg(2, 0xFF)]) == INT32_MIN),
"integer divide error");
vm_binop_integer(/);
VM_OP(DOP_DIVIDE_IMMEDIATE)
{
int32_t op1 = dst_unwrap_integer(stack[oparg(2, 0xFF)]);
int32_t op2 = *((int32_t *)pc) >> 24;
/* Check for degenerate integer division (divide by zero, and dividing
* min value by -1). These checks could be omitted if the arg is not
* 0 or -1. */
if (op2 == 0)
vm_throw("integer divide error");
if (op2 == -1 && op1 == INT32_MIN)
vm_throw("integer divide error");
else
stack[oparg(1, 0xFF)] = dst_wrap_integer(op1 / op2);
pc++;
vm_next();
}
VM_OP(DOP_DIVIDE_REAL)
vm_binop_real(/);
VM_OP(DOP_DIVIDE)
{
Dst op1 = stack[oparg(2, 0xFF)];
Dst op2 = stack[oparg(3, 0xFF)];
vm_assert(dst_checktype(op1, DST_INTEGER) || dst_checktype(op1, DST_REAL), "expected number");
vm_assert(dst_checktype(op2, DST_INTEGER) || dst_checktype(op2, DST_REAL), "expected number");
if (dst_checktype(op2, DST_INTEGER) && dst_unwrap_integer(op2) == 0)
vm_throw("integer divide error");
if (dst_checktype(op2, DST_INTEGER) && dst_unwrap_integer(op2) == -1 &&
dst_checktype(op1, DST_INTEGER) && dst_unwrap_integer(op1) == INT32_MIN)
vm_throw("integer divide error");
stack[oparg(1, 0xFF)] = dst_checktype(op1, DST_INTEGER)
? (dst_checktype(op2, DST_INTEGER)
? dst_wrap_integer(dst_unwrap_integer(op1) / dst_unwrap_integer(op2))
: dst_wrap_real((double)dst_unwrap_integer(op1) / dst_unwrap_real(op2)))
: (dst_checktype(op2, DST_INTEGER)
? dst_wrap_real(dst_unwrap_real(op1) / (double)dst_unwrap_integer(op2))
: dst_wrap_real(dst_unwrap_real(op1) / dst_unwrap_real(op2)));
pc++;
vm_next();
}
VM_OP(DOP_BAND)
vm_binop_integer(&);
VM_OP(DOP_BOR)
vm_binop_integer(|);
VM_OP(DOP_BXOR)
vm_binop_integer(^);
VM_OP(DOP_BNOT)
stack[oparg(1, 0xFF)] = dst_wrap_integer(~dst_unwrap_integer(stack[oparg(2, 0xFFFF)]));
vm_next();
VM_OP(DOP_SHIFT_RIGHT_UNSIGNED)
stack[oparg(1, 0xFF)] = dst_wrap_integer(
(int32_t)(((uint32_t)dst_unwrap_integer(stack[oparg(2, 0xFF)]))
>>
dst_unwrap_integer(stack[oparg(3, 0xFF)]))
);
pc++;
vm_next();
VM_OP(DOP_SHIFT_RIGHT_UNSIGNED_IMMEDIATE)
stack[oparg(1, 0xFF)] = dst_wrap_integer(
(int32_t) (((uint32_t)dst_unwrap_integer(stack[oparg(2, 0xFF)])) >> oparg(3, 0xFF))
);
pc++;
vm_next();
VM_OP(DOP_SHIFT_RIGHT)
vm_binop_integer(>>);
VM_OP(DOP_SHIFT_RIGHT_IMMEDIATE)
stack[oparg(1, 0xFF)] = dst_wrap_integer(
(int32_t)(dst_unwrap_integer(stack[oparg(2, 0xFF)]) >> oparg(3, 0xFF))
);
pc++;
vm_next();
VM_OP(DOP_SHIFT_LEFT)
vm_binop_integer(<<);
VM_OP(DOP_SHIFT_LEFT_IMMEDIATE)
stack[oparg(1, 0xFF)] = dst_wrap_integer(
dst_unwrap_integer(stack[oparg(2, 0xFF)]) << oparg(3, 0xFF)
);
pc++;
vm_next();
VM_OP(DOP_MOVE_NEAR)
stack[oparg(1, 0xFF)] = stack[oparg(2, 0xFFFF)];
pc++;
vm_next();
VM_OP(DOP_MOVE_FAR)
stack[oparg(2, 0xFFFF)] = stack[oparg(1, 0xFF)];
pc++;
vm_next();
VM_OP(DOP_JUMP)
pc += (*(int32_t *)pc) >> 8;
vm_next();
VM_OP(DOP_JUMP_IF)
if (dst_truthy(stack[oparg(1, 0xFF)])) {
pc += (*(int32_t *)pc) >> 16;
} else {
pc++;
}
vm_next();
VM_OP(DOP_JUMP_IF_NOT)
if (dst_truthy(stack[oparg(1, 0xFF)])) {
pc++;
} else {
pc += (*(int32_t *)pc) >> 16;
}
vm_next();
VM_OP(DOP_LESS_THAN)
stack[oparg(1, 0xFF)] = dst_wrap_boolean(dst_compare(
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]
) < 0);
pc++;
vm_next();
VM_OP(DOP_GREATER_THAN)
stack[oparg(1, 0xFF)] = dst_wrap_boolean(dst_compare(
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]
) > 0);
pc++;
vm_next();
VM_OP(DOP_EQUALS)
stack[oparg(1, 0xFF)] = dst_wrap_boolean(dst_equals(
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]
));
pc++;
vm_next();
VM_OP(DOP_COMPARE)
stack[oparg(1, 0xFF)] = dst_wrap_integer(dst_compare(
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]
));
pc++;
vm_next();
VM_OP(DOP_LOAD_NIL)
stack[oparg(1, 0xFFFFFF)] = dst_wrap_nil();
pc++;
vm_next();
VM_OP(DOP_LOAD_TRUE)
stack[oparg(1, 0xFFFFFF)] = dst_wrap_boolean(1);
pc++;
vm_next();
VM_OP(DOP_LOAD_FALSE)
stack[oparg(1, 0xFFFFFF)] = dst_wrap_boolean(0);
pc++;
vm_next();
VM_OP(DOP_LOAD_INTEGER)
stack[oparg(1, 0xFF)] = dst_wrap_integer(*((int32_t *)pc) >> 16);
pc++;
vm_next();
VM_OP(DOP_LOAD_CONSTANT)
{
int32_t index = oparg(2, 0xFFFF);
vm_assert(index < func->def->constants_length, "invalid constant");
stack[oparg(1, 0xFF)] = func->def->constants[index];
pc++;
vm_next();
}
VM_OP(DOP_LOAD_SELF)
stack[oparg(1, 0xFFFFFF)] = dst_wrap_function(func);
pc++;
vm_next();
VM_OP(DOP_LOAD_UPVALUE)
{
int32_t eindex = oparg(2, 0xFF);
int32_t vindex = oparg(3, 0xFF);
DstFuncEnv *env;
vm_assert(func->def->environments_length > eindex, "invalid upvalue");
env = func->envs[eindex];
vm_assert(env->length > vindex, "invalid upvalue");
if (env->offset) {
/* On stack */
stack[oparg(1, 0xFF)] = env->as.fiber->data[env->offset + vindex];
} else {
/* Off stack */
stack[oparg(1, 0xFF)] = env->as.values[vindex];
}
pc++;
vm_next();
}
VM_OP(DOP_SET_UPVALUE)
{
int32_t eindex = oparg(2, 0xFF);
int32_t vindex = oparg(3, 0xFF);
DstFuncEnv *env;
vm_assert(func->def->environments_length > eindex, "invalid upvalue");
env = func->envs[eindex];
vm_assert(env->length > vindex, "invalid upvalue");
if (env->offset) {
env->as.fiber->data[env->offset + vindex] = stack[oparg(1, 0xFF)];
} else {
env->as.values[vindex] = stack[oparg(1, 0xFF)];
}
pc++;
vm_next();
}
VM_OP(DOP_CLOSURE)
{
DstFuncDef *fd;
DstFunction *fn;
int32_t elen;
vm_assert((int32_t)oparg(2, 0xFFFF) < func->def->defs_length, "invalid funcdef");
fd = func->def->defs[(int32_t)oparg(2, 0xFFFF)];
elen = fd->environments_length;
fn = dst_gcalloc(DST_MEMORY_FUNCTION, sizeof(DstFunction) + (elen * sizeof(DstFuncEnv *)));
fn->def = fd;
{
int32_t i;
for (i = 0; i < elen; ++i) {
int32_t inherit = fd->environments[i];
if (inherit == -1) {
DstStackFrame *frame = (DstStackFrame *)stack - 1;
if (!frame->env) {
/* Lazy capture of current stack frame */
DstFuncEnv *env = dst_gcalloc(DST_MEMORY_FUNCENV, sizeof(DstFuncEnv));
env->offset = dst_vm_fiber->frame;
env->as.fiber = dst_vm_fiber;
env->length = func->def->slotcount;
frame->env = env;
}
fn->envs[i] = frame->env;
} else {
fn->envs[i] = func->envs[inherit];
}
}
}
stack[oparg(1, 0xFF)] = dst_wrap_function(fn);
pc++;
vm_checkgc_next();
}
VM_OP(DOP_PUSH)
dst_fiber_push(dst_vm_fiber, stack[oparg(1, 0xFFFFFF)]);
pc++;
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
vm_checkgc_next();
VM_OP(DOP_PUSH_2)
dst_fiber_push2(dst_vm_fiber,
stack[oparg(1, 0xFF)],
stack[oparg(2, 0xFFFF)]);
pc++;
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
vm_checkgc_next();
VM_OP(DOP_PUSH_3)
dst_fiber_push3(dst_vm_fiber,
stack[oparg(1, 0xFF)],
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]);
pc++;
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
vm_checkgc_next();
VM_OP(DOP_PUSH_ARRAY)
{
const Dst *vals;
int32_t len;
if (dst_seq_view(stack[oparg(1, 0xFFFFFF)], &vals, &len)) {
dst_fiber_pushn(dst_vm_fiber, vals, len);
} else {
vm_throw("expected array/tuple");
}
}
pc++;
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
vm_checkgc_next();
VM_OP(DOP_CALL)
{
Dst callee = stack[oparg(2, 0xFFFF)];
if (dst_vm_fiber->maxstack &&
dst_vm_fiber->stacktop > dst_vm_fiber->maxstack) {
vm_throw("stack overflow");
}
if (dst_checktype(callee, DST_FUNCTION)) {
func = dst_unwrap_function(callee);
dst_stack_frame(stack)->pc = pc;
dst_fiber_funcframe(dst_vm_fiber, func);
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
pc = func->def->bytecode;
vm_checkgc_next();
} else if (dst_checktype(callee, DST_CFUNCTION)) {
DstArgs args;
args.n = dst_vm_fiber->stacktop - dst_vm_fiber->stackstart;
dst_fiber_cframe(dst_vm_fiber);
retreg = dst_wrap_nil();
args.v = dst_vm_fiber->data + dst_vm_fiber->frame;
args.ret = &retreg;
if (dst_unwrap_cfunction(callee)(args)) {
goto vm_error;
}
goto vm_return_cfunc;
}
vm_throw("expected function");
}
VM_OP(DOP_TAILCALL)
{
Dst callee = stack[oparg(1, 0xFFFFFF)];
if (dst_checktype(callee, DST_FUNCTION)) {
func = dst_unwrap_function(callee);
dst_fiber_funcframe_tail(dst_vm_fiber, func);
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
pc = func->def->bytecode;
vm_checkgc_next();
} else if (dst_checktype(callee, DST_CFUNCTION)) {
DstArgs args;
args.n = dst_vm_fiber->stacktop - dst_vm_fiber->stackstart;
dst_fiber_cframe(dst_vm_fiber);
retreg = dst_wrap_nil();
args.v = dst_vm_fiber->data + dst_vm_fiber->frame;
args.ret = &retreg;
if (dst_unwrap_cfunction(callee)(args)) {
goto vm_error;
}
goto vm_return_cfunc_tail;
}
vm_throw("expected function");
}
VM_OP(DOP_TRANSFER)
{
int status;
DstFiber *nextfiber;
DstStackFrame *frame = dst_stack_frame(stack);
Dst temp = stack[oparg(2, 0xFF)];
retreg = stack[oparg(3, 0xFF)];
vm_assert(dst_checktype(temp, DST_FIBER) ||
dst_checktype(temp, DST_NIL), "expected fiber");
nextfiber = dst_checktype(temp, DST_FIBER)
? dst_unwrap_fiber(temp)
: dst_vm_fiber->parent;
/* Check for root fiber */
if (NULL == nextfiber) {
frame->pc = pc;
*returnreg = retreg;
dst_vm_stackn--;
return 0;
}
status = nextfiber->status;
vm_assert(status == DST_FIBER_PENDING ||
status == DST_FIBER_NEW, "can only transfer to new or pending fiber");
frame->pc = pc;
dst_vm_fiber->status = DST_FIBER_PENDING;
dst_vm_fiber = nextfiber;
vm_init_fiber_state();
if (status == DST_FIBER_PENDING) {
/* The next fiber is currently on a transfer instruction. */
stack[oparg(1, 0xFF)] = retreg;
pc++;
} else {
/* The next fiber is new and is on the first instruction */
if ((func->def->flags & DST_FUNCDEF_FLAG_VARARG) &&
!func->def->arity) {
/* Fully var arg function */
Dst *tup = dst_tuple_begin(1);
tup[0] = retreg;
stack[0] = dst_wrap_tuple(dst_tuple_end(tup));
} else if (func->def->arity) {
/* Non zero arity function */
stack[0] = retreg;
}
}
vm_checkgc_next();
}
VM_OP(DOP_PUT)
dst_put(stack[oparg(1, 0xFF)],
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]);
++pc;
vm_checkgc_next();
VM_OP(DOP_PUT_INDEX)
dst_setindex(stack[oparg(1, 0xFF)],
stack[oparg(2, 0xFF)],
oparg(3, 0xFF));
++pc;
vm_checkgc_next();
VM_OP(DOP_GET)
stack[oparg(1, 0xFF)] = dst_get(
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]);
++pc;
vm_next();
VM_OP(DOP_GET_INDEX)
stack[oparg(1, 0xFF)] = dst_getindex(
stack[oparg(2, 0xFF)],
oparg(3, 0xFF));
++pc;
vm_next();
VM_OP(DOP_LENGTH)
stack[oparg(1, 0xFF)] = dst_wrap_integer(dst_length(stack[oparg(2, 0xFFFF)]));
++pc;
vm_next();
/* Return from c function. Simpler than retuning from dst function */
vm_return_cfunc:
{
dst_fiber_popframe(dst_vm_fiber);
if (dst_update_fiber(DST_FIBER_MASK_RETURN)) goto vm_exit_value;
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
stack[oparg(1, 0xFF)] = retreg;
pc++;
vm_checkgc_next();
}
/* Return from a cfunction that is in tail position (pop 2 stack frames) */
vm_return_cfunc_tail:
{
dst_fiber_popframe(dst_vm_fiber);
if (dst_update_fiber(DST_FIBER_MASK_RETURN)) goto vm_exit_value;
goto vm_return;
}
/* Handle returning from stack frame. Expect return value in retreg */
vm_return:
{
dst_fiber_popframe(dst_vm_fiber);
if (dst_update_fiber(DST_FIBER_MASK_RETURN)) goto vm_exit_value;
goto vm_reset;
}
/* Handle errors from c functions and vm opcodes */
vm_error:
{
dst_vm_fiber->status = DST_FIBER_ERROR;
if (dst_update_fiber(DST_FIBER_MASK_ERROR)) goto vm_exit_error;
goto vm_reset;
}
/* Handle debugger interrupts */
vm_debug:
{
dst_vm_fiber->status = DST_FIBER_DEBUG;
if (dst_update_fiber(DST_FIBER_MASK_DEBUG)) goto vm_exit_debug;
goto vm_reset;
}
/* Reset state of machine */
vm_reset:
{
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
func = dst_stack_frame(stack)->func;
pc = dst_stack_frame(stack)->pc;
stack[oparg(1, 0xFF)] = retreg;
pc++;
vm_checkgc_next();
}
/* Exit loop with return value */
vm_exit_value:
{
*returnreg = retreg;
dst_vm_stackn--;
return 0;
}
/* Exit loop with error value */
vm_exit_error:
{
*returnreg = retreg;
dst_vm_stackn--;
return 1;
}
/* Exit loop with debug */
vm_exit_debug:
{
*returnreg = dst_wrap_nil();
dst_vm_stackn--;
return 2;
}
VM_END()
#undef oparg
#undef vm_error
#undef vm_assert
#undef vm_binop
#undef vm_binop_real
#undef vm_binop_integer
#undef vm_binop_immediate
#undef vm_init_fiber_state
}
/* Run the vm with a given function. This function is
* called to start the vm. */
int dst_run(Dst callee, Dst *returnreg) {
if (dst_vm_fiber) {
dst_fiber_reset(dst_vm_fiber);
} else {
dst_vm_fiber = dst_fiber(64);
}
if (dst_checktype(callee, DST_CFUNCTION)) {
DstArgs args;
*returnreg = dst_wrap_nil();
dst_fiber_cframe(dst_vm_fiber);
args.n = 0;
args.v = dst_vm_fiber->data + dst_vm_fiber->frame;
args.ret = returnreg;
return dst_unwrap_cfunction(callee)(args);
} else if (dst_checktype(callee, DST_FUNCTION)) {
dst_fiber_funcframe(dst_vm_fiber, dst_unwrap_function(callee));
return dst_continue(returnreg);
}
*returnreg = dst_cstringv("expected function");
return 1;
}
/* Helper for calling a function */
static int dst_call_help(Dst callee, Dst *returnreg, int32_t argn, const Dst* argv) {
dst_vm_fiber = dst_fiber(64);
dst_fiber_pushn(dst_vm_fiber, argv, argn);
if (dst_checktype(callee, DST_CFUNCTION)) {
DstArgs args;
*returnreg = dst_wrap_nil();
dst_fiber_cframe(dst_vm_fiber);
args.n = argn;
args.v = dst_vm_fiber->data + dst_vm_fiber->frame;
args.ret = returnreg;
return dst_unwrap_cfunction(callee)(args);
} else if (dst_checktype(callee, DST_FUNCTION)) {
dst_fiber_funcframe(dst_vm_fiber, dst_unwrap_function(callee));
return dst_continue(returnreg);
} else {
*returnreg = dst_cstringv("expected function");
return 1;
}
}
/* Run from inside a cfunction. This should only be used for
* short functions as it prevents re-entering the current fiber
* and suspend garbage collection. Currently used in the compiler
* for macro evaluation. */
int dst_call_suspend(Dst callee, Dst *returnreg, int32_t argn, const Dst *argv) {
int ret;
int lock;
DstFiber *oldfiber = dst_vm_fiber;
lock = dst_vm_gc_suspend++;
ret = dst_call_help(callee, returnreg, argn, argv);
dst_vm_fiber = oldfiber;
dst_vm_gc_suspend = lock;
return ret;
}
/* Run from inside a cfunction. This will not suspend GC, so
* the caller must be sure that no Dst*'s are left dangling in the calling function.
* Such values can be locked with dst_gcroot and unlocked with dst_gcunroot. */
int dst_call(Dst callee, Dst *returnreg, int32_t argn, const Dst *argv) {
int ret;
DstFiber *oldfiber = dst_vm_fiber;
dst_gcroot(dst_wrap_fiber(oldfiber));
ret = dst_call_help(callee, returnreg, argn, argv);
dst_gcunroot(dst_wrap_fiber(oldfiber));
dst_vm_fiber = oldfiber;
return ret;
}
/* Setup functions */
int dst_init() {
/* Garbage collection */
dst_vm_blocks = NULL;
dst_vm_next_collection = 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 */
dst_vm_gc_interval = 0x100000;
dst_symcache_init();
/* Set thread */
dst_vm_fiber = NULL;
/* Initialize gc roots */
dst_vm_roots = NULL;
dst_vm_root_count = 0;
dst_vm_root_capacity = 0;
return 0;
}
/* Clear all memory associated with the VM */
void dst_deinit() {
dst_clear_memory();
dst_vm_fiber = NULL;
dst_symcache_deinit();
free(dst_vm_roots);
dst_vm_roots = NULL;
dst_vm_root_count = 0;
dst_vm_root_capacity = 0;
}
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