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001917f8d9
janet/src/core/vm.c
Calvin Rose 001917f8d9 Begin clean up of vm.c 
Replace the oparg macro with 5 named virtual registers, combine
pc++ with vm_next() macro to be more terse, and move setup and
teardown logic of janet_continue into a separate function.

These changes are preparation for using setjmp/longjmp to do
error handling in the VM. Introducing longjmp for error handling in
the VM would allow it to be used in the C API, which could result in
simpler, more compact code.
2019-01-04 20:08:43 -05:00

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/*
* Copyright (c) 2018 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 <janet/janet.h>
#include "state.h"
#include "fiber.h"
#include "gc.h"
#include "symcache.h"
#include "util.h"
/* VM state */
JANET_THREAD_LOCAL JanetTable *janet_vm_registry;
JANET_THREAD_LOCAL int janet_vm_stackn = 0;
JANET_THREAD_LOCAL JanetFiber *janet_vm_fiber = NULL;
/* Virtual regsiters
*
* One instruction word
* CC | BB | AA | OP
* DD | DD | DD | OP
* EE | EE | AA | OP
*/
#define A ((*pc >> 8) & 0xFF)
#define B ((*pc >> 16) & 0xFF)
#define C (*pc >> 24)
#define D (*pc >> 8)
#define E (*pc >> 16)
/* Signed interpretations of registers */
#define CS (*((int32_t *)pc) >> 24)
#define DS (*((int32_t *)pc) >> 8)
#define ES (*((int32_t *)pc) >> 16)
/* How we dispatch instructions. By default, we use
* a switch inside an infinite loop. For GCC/clang, we use
* computed gotos. */
#ifdef ____GNUC__
#define VM_START() { goto *op_lookup[first_opcode];
#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_JOP_NOOP,
&&label_JOP_ERROR,
&&label_JOP_TYPECHECK,
&&label_JOP_RETURN,
&&label_JOP_RETURN_NIL,
&&label_JOP_ADD_IMMEDIATE,
&&label_JOP_ADD,
&&label_JOP_SUBTRACT,
&&label_JOP_MULTIPLY_IMMEDIATE,
&&label_JOP_MULTIPLY,
&&label_JOP_DIVIDE_IMMEDIATE,
&&label_JOP_DIVIDE,
&&label_JOP_BAND,
&&label_JOP_BOR,
&&label_JOP_BXOR,
&&label_JOP_BNOT,
&&label_JOP_SHIFT_LEFT,
&&label_JOP_SHIFT_LEFT_IMMEDIATE,
&&label_JOP_SHIFT_RIGHT,
&&label_JOP_SHIFT_RIGHT_IMMEDIATE,
&&label_JOP_SHIFT_RIGHT_UNSIGNED,
&&label_JOP_SHIFT_RIGHT_UNSIGNED_IMMEDIATE,
&&label_JOP_MOVE_FAR,
&&label_JOP_MOVE_NEAR,
&&label_JOP_JUMP,
&&label_JOP_JUMP_IF,
&&label_JOP_JUMP_IF_NOT,
&&label_JOP_GREATER_THAN,
&&label_JOP_GREATER_THAN_IMMEDIATE,
&&label_JOP_LESS_THAN,
&&label_JOP_LESS_THAN_IMMEDIATE,
&&label_JOP_EQUALS,
&&label_JOP_EQUALS_IMMEDIATE,
&&label_JOP_COMPARE,
&&label_JOP_LOAD_NIL,
&&label_JOP_LOAD_TRUE,
&&label_JOP_LOAD_FALSE,
&&label_JOP_LOAD_INTEGER,
&&label_JOP_LOAD_CONSTANT,
&&label_JOP_LOAD_UPVALUE,
&&label_JOP_LOAD_SELF,
&&label_JOP_SET_UPVALUE,
&&label_JOP_CLOSURE,
&&label_JOP_PUSH,
&&label_JOP_PUSH_2,
&&label_JOP_PUSH_3,
&&label_JOP_PUSH_ARRAY,
&&label_JOP_CALL,
&&label_JOP_TAILCALL,
&&label_JOP_RESUME,
&&label_JOP_SIGNAL,
&&label_JOP_GET,
&&label_JOP_PUT,
&&label_JOP_GET_INDEX,
&&label_JOP_PUT_INDEX,
&&label_JOP_LENGTH,
&&label_JOP_MAKE_ARRAY,
&&label_JOP_MAKE_BUFFER,
&&label_JOP_MAKE_STRING,
&&label_JOP_MAKE_STRUCT,
&&label_JOP_MAKE_TABLE,
&&label_JOP_MAKE_TUPLE,
&&label_JOP_NUMERIC_LESS_THAN,
&&label_JOP_NUMERIC_LESS_THAN_EQUAL,
&&label_JOP_NUMERIC_GREATER_THAN,
&&label_JOP_NUMERIC_GREATER_THAN_EQUAL,
&&label_JOP_NUMERIC_EQUAL,
&&label_unknown_op
};
#else
#define VM_START() uint8_t opcode = first_opcode; for (;;) {switch(opcode) {
#define VM_END() }}
#define VM_OP(op) case op :
#define VM_DEFAULT() default:
#define vm_next() opcode = *pc & 0xFF; continue
#endif
/* Next instruction variations */
#define janet_maybe_collect() do {\
if (janet_vm_next_collection >= janet_vm_gc_interval) janet_collect(); } while (0)
#define vm_checkgc_next() janet_maybe_collect(); vm_next()
#define vm_pcnext() pc++; vm_next()
#define vm_checkgc_pcnext() janet_maybe_collect(); vm_pcnext()
/* Handle certain errors in main vm loop */
#define vm_throw(e) do { retreg = janet_cstringv(e); goto vm_error; } while (0)
#define vm_assert(cond, e) do {if (!(cond)) vm_throw((e)); } while (0)
#define vm_assert_type(X, T) do { \
if (!(janet_checktype((X), (T)))) { \
expected_types = 1 << (T); \
retreg = (X); \
goto vm_type_error; \
} \
} while (0)
#define vm_assert_types(X, TS) do { \
if (!(janet_checktypes((X), (TS)))) { \
expected_types = (TS); \
retreg = (X); \
goto vm_type_error; \
} \
} while (0)
/* Templates for certain patterns in opcodes */
#define vm_binop_immediate(op)\
{\
Janet op1 = stack[B];\
vm_assert_type(op1, JANET_NUMBER);\
double x1 = janet_unwrap_number(op1);\
stack[A] = janet_wrap_number(x1 op CS);\
vm_pcnext();\
}
#define _vm_bitop_immediate(op, type1)\
{\
Janet op1 = stack[B];\
vm_assert_type(op1, JANET_NUMBER);\
type1 x1 = (type1) janet_unwrap_integer(op1);\
stack[A] = janet_wrap_integer(x1 op CS);\
vm_pcnext();\
}
#define vm_bitop_immediate(op) _vm_bitop_immediate(op, int32_t);
#define vm_bitopu_immediate(op) _vm_bitop_immediate(op, uint32_t);
#define _vm_binop(op, wrap)\
{\
Janet op1 = stack[B];\
Janet op2 = stack[C];\
vm_assert_type(op1, JANET_NUMBER);\
vm_assert_type(op2, JANET_NUMBER);\
double x1 = janet_unwrap_number(op1);\
double x2 = janet_unwrap_number(op2);\
stack[A] = wrap(x1 op x2);\
vm_pcnext();\
}
#define vm_binop(op) _vm_binop(op, janet_wrap_number)
#define vm_numcomp(op) _vm_binop(op, janet_wrap_boolean)
#define _vm_bitop(op, type1)\
{\
Janet op1 = stack[B];\
Janet op2 = stack[C];\
vm_assert_type(op1, JANET_NUMBER);\
vm_assert_type(op2, JANET_NUMBER);\
type1 x1 = (type1) janet_unwrap_integer(op1);\
int32_t x2 = janet_unwrap_integer(op2);\
stack[A] = janet_wrap_integer(x1 op x2);\
vm_pcnext();\
}
#define vm_bitop(op) _vm_bitop(op, int32_t)
#define vm_bitopu(op) _vm_bitop(op, uint32_t)
/* Interpreter main loop */
static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
/* interpreter state */
register Janet *stack;
register uint32_t *pc;
register JanetFunction *func;
/* Keep in mind the garbage collector cannot see this value.
* Values stored here should be used immediately */
Janet retreg;
/* Expected types on type error */
uint16_t expected_types;
/* Signal to return when done */
JanetSignal signal = JANET_SIGNAL_OK;
/* Setup fiber state */
stack = fiber->data + fiber->frame;
pc = janet_stack_frame(stack)->pc;
func = janet_stack_frame(stack)->func;
if (fiber->child) {
/* Check for child fiber. If there is a child, run child before self.
* This should only be hit when the current fiber is pending on a RESUME
* instruction. */
retreg = in;
goto vm_resume_child;
}
if (janet_fiber_status(fiber) != JANET_STATUS_NEW &&
((*pc & 0xFF) == JOP_SIGNAL)) {
/* Only should be hit if child is waiting on a SIGNAL instruction */
/* If waiting for response to signal, use input and increment pc */
stack[A] = in;
pc++;
}
/* The first opcode to execute. If the first opcode has
* the breakpoint bit set and we were in the debug state, skip
* that first breakpoint. */
uint8_t first_opcode = (janet_fiber_status(fiber) == JANET_STATUS_DEBUG)
? (*pc & 0x7F)
: (*pc & 0xFF);
/* Main interpreter loop. Semantically is a switch on
* (*pc & 0xFF) inside of an infinte loop. */
VM_START();
VM_DEFAULT();
signal = JANET_SIGNAL_DEBUG;
retreg = janet_wrap_nil();
goto vm_exit;
VM_OP(JOP_NOOP)
vm_pcnext();
VM_OP(JOP_ERROR)
retreg = stack[A];
goto vm_error;
VM_OP(JOP_TYPECHECK)
if (!janet_checktypes(stack[A], E)) {
JanetArgs tempargs;
tempargs.n = A + 1;
tempargs.v = stack;
janet_typemany_err(tempargs, A, E);
goto vm_error;
}
vm_pcnext();
VM_OP(JOP_RETURN)
retreg = stack[D];
goto vm_return;
VM_OP(JOP_RETURN_NIL)
retreg = janet_wrap_nil();
goto vm_return;
VM_OP(JOP_ADD_IMMEDIATE)
vm_binop_immediate(+);
VM_OP(JOP_ADD)
vm_binop(+);
VM_OP(JOP_SUBTRACT)
vm_binop(-);
VM_OP(JOP_MULTIPLY_IMMEDIATE)
vm_binop_immediate(*);
VM_OP(JOP_MULTIPLY)
vm_binop(*);
VM_OP(JOP_NUMERIC_LESS_THAN)
vm_numcomp(<);
VM_OP(JOP_NUMERIC_LESS_THAN_EQUAL)
vm_numcomp(<=);
VM_OP(JOP_NUMERIC_GREATER_THAN)
vm_numcomp(>);
VM_OP(JOP_NUMERIC_GREATER_THAN_EQUAL)
vm_numcomp(>=);
VM_OP(JOP_NUMERIC_EQUAL)
vm_numcomp(==);
VM_OP(JOP_DIVIDE_IMMEDIATE)
vm_binop_immediate(/);
VM_OP(JOP_DIVIDE)
vm_binop(/);
VM_OP(JOP_BAND)
vm_bitop(&);
VM_OP(JOP_BOR)
vm_bitop(|);
VM_OP(JOP_BXOR)
vm_bitop(^);
VM_OP(JOP_BNOT)
{
Janet op = stack[E];
vm_assert_type(op, JANET_NUMBER);
stack[A] = janet_wrap_integer(~janet_unwrap_integer(op));
vm_pcnext();
}
VM_OP(JOP_SHIFT_RIGHT_UNSIGNED)
vm_bitopu(>>);
VM_OP(JOP_SHIFT_RIGHT_UNSIGNED_IMMEDIATE)
vm_bitopu_immediate(>>);
VM_OP(JOP_SHIFT_RIGHT)
vm_bitop(>>);
VM_OP(JOP_SHIFT_RIGHT_IMMEDIATE)
vm_bitop_immediate(>>);
VM_OP(JOP_SHIFT_LEFT)
vm_bitop(<<);
VM_OP(JOP_SHIFT_LEFT_IMMEDIATE)
vm_bitop_immediate(<<);
VM_OP(JOP_MOVE_NEAR)
stack[A] = stack[E];
vm_pcnext();
VM_OP(JOP_MOVE_FAR)
stack[E] = stack[A];
vm_pcnext();
VM_OP(JOP_JUMP)
pc += DS;
vm_next();
VM_OP(JOP_JUMP_IF)
if (janet_truthy(stack[A])) {
pc += ES;
} else {
pc++;
}
vm_next();
VM_OP(JOP_JUMP_IF_NOT)
if (janet_truthy(stack[A])) {
pc++;
} else {
pc += ES;
}
vm_next();
VM_OP(JOP_LESS_THAN)
stack[A] = janet_wrap_boolean(janet_compare(stack[B], stack[C]) < 0);
vm_pcnext();
VM_OP(JOP_LESS_THAN_IMMEDIATE)
stack[A] = janet_wrap_boolean(janet_unwrap_integer(stack[B]) < CS);
vm_pcnext();
VM_OP(JOP_GREATER_THAN)
stack[A] = janet_wrap_boolean(janet_compare(stack[B], stack[C]) > 0);
vm_pcnext();
VM_OP(JOP_GREATER_THAN_IMMEDIATE)
stack[A] = janet_wrap_boolean(janet_unwrap_integer(stack[B]) > CS);
vm_pcnext();
VM_OP(JOP_EQUALS)
stack[A] = janet_wrap_boolean(janet_equals(stack[B], stack[C]));
vm_pcnext();
VM_OP(JOP_EQUALS_IMMEDIATE)
stack[A] = janet_wrap_boolean(janet_unwrap_integer(stack[B]) == CS);
vm_pcnext();
VM_OP(JOP_COMPARE)
stack[A] = janet_wrap_integer(janet_compare(stack[B], stack[C]));
vm_pcnext();
VM_OP(JOP_LOAD_NIL)
stack[D] = janet_wrap_nil();
vm_pcnext();
VM_OP(JOP_LOAD_TRUE)
stack[D] = janet_wrap_true();
vm_pcnext();
VM_OP(JOP_LOAD_FALSE)
stack[D] = janet_wrap_false();
vm_pcnext();
VM_OP(JOP_LOAD_INTEGER)
stack[A] = janet_wrap_integer(ES);
vm_pcnext();
VM_OP(JOP_LOAD_CONSTANT)
{
int32_t cindex = (int32_t)E;
vm_assert(cindex < func->def->constants_length, "invalid constant");
stack[A] = func->def->constants[cindex];
vm_pcnext();
}
VM_OP(JOP_LOAD_SELF)
stack[D] = janet_wrap_function(func);
vm_pcnext();
VM_OP(JOP_LOAD_UPVALUE)
{
int32_t eindex = B;
int32_t vindex = C;
JanetFuncEnv *env;
vm_assert(func->def->environments_length > eindex, "invalid upvalue environment");
env = func->envs[eindex];
vm_assert(env->length > vindex, "invalid upvalue index");
if (env->offset) {
/* On stack */
stack[A] = env->as.fiber->data[env->offset + vindex];
} else {
/* Off stack */
stack[A] = env->as.values[vindex];
}
vm_pcnext();
}
VM_OP(JOP_SET_UPVALUE)
{
int32_t eindex = B;
int32_t vindex = C;
JanetFuncEnv *env;
vm_assert(func->def->environments_length > eindex, "invalid upvalue environment");
env = func->envs[eindex];
vm_assert(env->length > vindex, "invalid upvalue index");
if (env->offset) {
env->as.fiber->data[env->offset + vindex] = stack[A];
} else {
env->as.values[vindex] = stack[A];
}
vm_pcnext();
}
VM_OP(JOP_CLOSURE)
{
JanetFuncDef *fd;
JanetFunction *fn;
int32_t elen;
int32_t defindex = (int32_t)E;
vm_assert(defindex < func->def->defs_length, "invalid funcdef");
fd = func->def->defs[defindex];
elen = fd->environments_length;
fn = janet_gcalloc(JANET_MEMORY_FUNCTION, sizeof(JanetFunction) + (elen * sizeof(JanetFuncEnv *)));
fn->def = fd;
{
int32_t i;
for (i = 0; i < elen; ++i) {
int32_t inherit = fd->environments[i];
if (inherit == -1) {
JanetStackFrame *frame = janet_stack_frame(stack);
if (!frame->env) {
/* Lazy capture of current stack frame */
JanetFuncEnv *env = janet_gcalloc(JANET_MEMORY_FUNCENV, sizeof(JanetFuncEnv));
env->offset = fiber->frame;
env->as.fiber = fiber;
env->length = func->def->slotcount;
frame->env = env;
}
fn->envs[i] = frame->env;
} else {
fn->envs[i] = func->envs[inherit];
}
}
}
stack[A] = janet_wrap_function(fn);
vm_checkgc_pcnext();
}
VM_OP(JOP_PUSH)
janet_fiber_push(fiber, stack[D]);
stack = fiber->data + fiber->frame;
vm_checkgc_pcnext();
VM_OP(JOP_PUSH_2)
janet_fiber_push2(fiber, stack[A], stack[E]);
stack = fiber->data + fiber->frame;
vm_checkgc_pcnext();
VM_OP(JOP_PUSH_3)
janet_fiber_push3(fiber, stack[A], stack[B], stack[C]);
stack = fiber->data + fiber->frame;
vm_checkgc_pcnext();
VM_OP(JOP_PUSH_ARRAY)
{
const Janet *vals;
int32_t len;
if (janet_indexed_view(stack[D], &vals, &len)) {
janet_fiber_pushn(fiber, vals, len);
} else {
retreg = stack[D];
expected_types = JANET_TFLAG_INDEXED;
goto vm_type_error;
}
}
stack = fiber->data + fiber->frame;
vm_checkgc_pcnext();
VM_OP(JOP_CALL)
{
Janet callee = stack[E];
if (fiber->maxstack &&
fiber->stacktop > fiber->maxstack) {
vm_throw("stack overflow");
}
if (janet_checktype(callee, JANET_FUNCTION)) {
func = janet_unwrap_function(callee);
janet_stack_frame(stack)->pc = pc;
if (janet_fiber_funcframe(fiber, func))
goto vm_arity_error;
stack = fiber->data + fiber->frame;
pc = func->def->bytecode;
vm_checkgc_next();
} else if (janet_checktype(callee, JANET_CFUNCTION)) {
JanetArgs args;
args.n = fiber->stacktop - fiber->stackstart;
janet_fiber_cframe(fiber, janet_unwrap_cfunction(callee));
retreg = janet_wrap_nil();
args.v = fiber->data + fiber->frame;
args.ret = &retreg;
if (janet_unwrap_cfunction(callee)(args)) {
signal = JANET_SIGNAL_ERROR;
goto vm_exit;
}
goto vm_return_cfunc;
} else {
int status;
int32_t argn = fiber->stacktop - fiber->stackstart;
Janet ds, key;
if (janet_checktypes(callee, JANET_TFLAG_INDEXED | JANET_TFLAG_DICTIONARY)) {
if (argn != 1) {
retreg = callee;
goto vm_arity_error_2;
}
ds = callee;
key = fiber->data[fiber->stackstart];
} else if (janet_checktypes(callee, JANET_TFLAG_SYMBOL | JANET_TFLAG_KEYWORD)) {
if (argn != 1) {
retreg = callee;
goto vm_arity_error_2;
}
ds = fiber->data[fiber->stackstart];
key = callee;
} else {
expected_types = JANET_TFLAG_CALLABLE;
retreg = callee;
goto vm_type_error;
}
fiber->stacktop = fiber->stackstart;
status = janet_get(ds, key, stack + A);
if (status == -2) {
vm_throw("expected integer key");
} else if (status == -1) {
vm_throw("expected table or struct");
}
vm_pcnext();
}
}
VM_OP(JOP_TAILCALL)
{
Janet callee = stack[D];
if (janet_checktype(callee, JANET_FUNCTION)) {
func = janet_unwrap_function(callee);
if (janet_fiber_funcframe_tail(fiber, func))
goto vm_arity_error;
stack = fiber->data + fiber->frame;
pc = func->def->bytecode;
vm_checkgc_next();
} else if (janet_checktype(callee, JANET_CFUNCTION)) {
JanetArgs args;
args.n = fiber->stacktop - fiber->stackstart;
janet_fiber_cframe(fiber, janet_unwrap_cfunction(callee));
retreg = janet_wrap_nil();
args.v = fiber->data + fiber->frame;
args.ret = &retreg;
if (janet_unwrap_cfunction(callee)(args)) {
signal = JANET_SIGNAL_ERROR;
goto vm_exit;
}
goto vm_return_cfunc_tail;
} else {
int status;
int32_t argn = fiber->stacktop - fiber->stackstart;
Janet ds, key;
if (janet_checktypes(callee, JANET_TFLAG_INDEXED | JANET_TFLAG_DICTIONARY)) {
if (argn != 1) {
retreg = callee;
goto vm_arity_error_2;
}
ds = callee;
key = fiber->data[fiber->stackstart];
} else if (janet_checktypes(callee, JANET_TFLAG_SYMBOL | JANET_TFLAG_KEYWORD)) {
if (argn != 1) {
retreg = callee;
goto vm_arity_error_2;
}
ds = fiber->data[fiber->stackstart];
key = callee;
} else {
expected_types = JANET_TFLAG_CALLABLE;
retreg = callee;
goto vm_type_error;
}
fiber->stacktop = fiber->stackstart;
status = janet_get(ds, key, &retreg);
if (status == -2) {
vm_throw("expected integer key");
} else if (status == -1) {
vm_throw("expected table or struct");
}
janet_fiber_popframe(fiber);
if (fiber->frame == 0) goto vm_exit;
goto vm_reset;
}
}
VM_OP(JOP_RESUME)
{
Janet fiberval = stack[B];
vm_assert_type(fiberval, JANET_FIBER);
retreg = stack[C];
fiber->child = janet_unwrap_fiber(fiberval);
goto vm_resume_child;
}
VM_OP(JOP_SIGNAL)
{
int32_t s = C;
if (s > JANET_SIGNAL_USER9) s = JANET_SIGNAL_USER9;
if (s < 0) s = 0;
signal = s;
retreg = stack[B];
goto vm_exit;
}
VM_OP(JOP_PUT)
{
Janet ds = stack[A];
Janet key = stack[B];
Janet value = stack[C];
int status = janet_put(ds, key, value);
if (status == -1) {
expected_types = JANET_TFLAG_ARRAY | JANET_TFLAG_BUFFER | JANET_TFLAG_TABLE;
retreg = ds;
goto vm_type_error;
} else if (status == -2) {
vm_throw("expected integer key for data structure");
} else if (status == -3) {
vm_throw("expected integer value for data structure");
}
vm_checkgc_pcnext();
}
VM_OP(JOP_PUT_INDEX)
{
Janet ds = stack[A];
Janet value = stack[B];
int32_t index = (int32_t)C;
int status = janet_putindex(ds, index, value);
if (status == -1) {
expected_types = JANET_TFLAG_ARRAY | JANET_TFLAG_BUFFER | JANET_TFLAG_TABLE;
retreg = ds;
goto vm_type_error;
} else if (status == -3) {
vm_throw("expected integer value for data structure");
}
vm_checkgc_pcnext();
}
VM_OP(JOP_GET)
{
Janet ds = stack[B];
Janet key = stack[C];
int status = janet_get(ds, key, stack + A);
if (status == -1) {
expected_types = JANET_TFLAG_LENGTHABLE;
retreg = ds;
goto vm_type_error;
} else if (status == -2) {
vm_throw("expected integer key for data structure");
}
vm_pcnext();
}
VM_OP(JOP_GET_INDEX)
{
Janet ds = stack[B];
int32_t index = C;
if (janet_getindex(ds, index, stack + A)) {
expected_types = JANET_TFLAG_LENGTHABLE;
retreg = ds;
goto vm_type_error;
}
vm_pcnext();
}
VM_OP(JOP_LENGTH)
{
Janet x = stack[E];
int32_t len;
if (janet_length(x, &len)) {
expected_types = JANET_TFLAG_LENGTHABLE;
retreg = x;
goto vm_type_error;
}
stack[A] = janet_wrap_integer(len);
vm_pcnext();
}
VM_OP(JOP_MAKE_ARRAY)
{
int32_t count = fiber->stacktop - fiber->stackstart;
Janet *mem = fiber->data + fiber->stackstart;
stack[D] = janet_wrap_array(janet_array_n(mem, count));
fiber->stacktop = fiber->stackstart;
vm_checkgc_pcnext();
}
VM_OP(JOP_MAKE_TUPLE)
{
int32_t count = fiber->stacktop - fiber->stackstart;
Janet *mem = fiber->data + fiber->stackstart;
stack[D] = janet_wrap_tuple(janet_tuple_n(mem, count));
fiber->stacktop = fiber->stackstart;
vm_checkgc_pcnext();
}
VM_OP(JOP_MAKE_TABLE)
{
int32_t count = fiber->stacktop - fiber->stackstart;
Janet *mem = fiber->data + fiber->stackstart;
if (count & 1)
vm_throw("expected even number of arguments to table constructor");
JanetTable *table = janet_table(count / 2);
for (int32_t i = 0; i < count; i += 2)
janet_table_put(table, mem[i], mem[i + 1]);
stack[D] = janet_wrap_table(table);
fiber->stacktop = fiber->stackstart;
vm_checkgc_pcnext();
}
VM_OP(JOP_MAKE_STRUCT)
{
int32_t count = fiber->stacktop - fiber->stackstart;
Janet *mem = fiber->data + fiber->stackstart;
if (count & 1)
vm_throw("expected even number of arguments to struct constructor");
JanetKV *st = janet_struct_begin(count / 2);
for (int32_t i = 0; i < count; i += 2)
janet_struct_put(st, mem[i], mem[i + 1]);
stack[D] = janet_wrap_struct(janet_struct_end(st));
fiber->stacktop = fiber->stackstart;
vm_checkgc_pcnext();
}
VM_OP(JOP_MAKE_STRING)
{
int32_t count = fiber->stacktop - fiber->stackstart;
Janet *mem = fiber->data + fiber->stackstart;
JanetBuffer buffer;
janet_buffer_init(&buffer, 10 * count);
for (int32_t i = 0; i < count; i++)
janet_to_string_b(&buffer, mem[i]);
stack[D] = janet_stringv(buffer.data, buffer.count);
janet_buffer_deinit(&buffer);
fiber->stacktop = fiber->stackstart;
vm_checkgc_pcnext();
}
VM_OP(JOP_MAKE_BUFFER)
{
int32_t count = fiber->stacktop - fiber->stackstart;
Janet *mem = fiber->data + fiber->stackstart;
JanetBuffer *buffer = janet_buffer(10 * count);
for (int32_t i = 0; i < count; i++)
janet_to_string_b(buffer, mem[i]);
stack[D] = janet_wrap_buffer(buffer);
fiber->stacktop = fiber->stackstart;
vm_checkgc_pcnext();
}
/* Return from c function. Simpler than returning from janet function */
vm_return_cfunc:
{
janet_fiber_popframe(fiber);
if (fiber->frame == 0) goto vm_exit;
stack = fiber->data + fiber->frame;
stack[A] = retreg;
vm_checkgc_pcnext();
}
/* Return from a cfunction that is in tail position (pop 2 stack frames) */
vm_return_cfunc_tail:
{
janet_fiber_popframe(fiber);
janet_fiber_popframe(fiber);
if (fiber->frame == 0) goto vm_exit;
goto vm_reset;
}
/* Handle returning from stack frame. Expect return value in retreg */
vm_return:
{
janet_fiber_popframe(fiber);
if (fiber->frame == 0) goto vm_exit;
goto vm_reset;
}
/* Handle function calls with bad arity */
vm_arity_error:
{
int32_t nargs = fiber->stacktop - fiber->stackstart;
retreg = janet_wrap_string(janet_formatc("%v called with %d argument%s, expected %d",
janet_wrap_function(func),
nargs,
nargs == 1 ? "" : "s",
func->def->arity));
signal = JANET_SIGNAL_ERROR;
goto vm_exit;
}
/* Handle calling a data structure, keyword, or symbol with bad arity */
vm_arity_error_2:
{
int32_t nargs = fiber->stacktop - fiber->stackstart;
retreg = janet_wrap_string(janet_formatc("%v called with %d argument%s, expected 1",
retreg,
nargs,
nargs == 1 ? "" : "s"));
signal = JANET_SIGNAL_ERROR;
goto vm_exit;
}
/* Resume a child fiber */
vm_resume_child:
{
JanetFiber *child = fiber->child;
JanetFiberStatus status = janet_fiber_status(child);
if (status == JANET_STATUS_ALIVE) vm_throw("cannot resume live fiber");
if (status == JANET_STATUS_DEAD) vm_throw("cannot resume dead fiber");
if (status == JANET_STATUS_ERROR) vm_throw("cannot resume errored fiber");
signal = janet_continue(child, retreg, &retreg);
if (signal != JANET_SIGNAL_OK) {
if (child->flags & (1 << signal)) {
/* Intercept signal */
signal = JANET_SIGNAL_OK;
fiber->child = NULL;
} else {
/* Propogate signal */
goto vm_exit;
}
} else {
fiber->child = NULL;
}
stack[A] = retreg;
vm_checkgc_pcnext();
}
/* Handle type errors. The found type is the type of retreg,
* the expected types are in the expected_types field. */
vm_type_error:
{
JanetBuffer errbuf;
janet_buffer_init(&errbuf, 10);
janet_buffer_push_cstring(&errbuf, "expected ");
janet_buffer_push_types(&errbuf, expected_types);
janet_buffer_push_cstring(&errbuf, ", got ");
janet_buffer_push_cstring(&errbuf, janet_type_names[janet_type(retreg)]);
retreg = janet_stringv(errbuf.data, errbuf.count);
janet_buffer_deinit(&errbuf);
signal = JANET_SIGNAL_ERROR;
goto vm_exit;
}
/* Handle errors from c functions and vm opcodes */
vm_error:
{
signal = JANET_SIGNAL_ERROR;
goto vm_exit;
}
/* Exit from vm loop. If signal is not set explicitely, does
* a successful return (JANET_SIGNAL_OK). */
vm_exit:
{
janet_stack_frame(stack)->pc = pc;
janet_fiber_push(fiber, retreg);
return signal;
}
/* Reset state of machine */
vm_reset:
{
stack = fiber->data + fiber->frame;
func = janet_stack_frame(stack)->func;
pc = janet_stack_frame(stack)->pc;
stack[A] = retreg;
vm_checkgc_pcnext();
}
VM_END()
}
/* Enter the main vm loop */
JanetSignal janet_continue(JanetFiber *fiber, Janet in, Janet *out) {
/* Check conditions */
if (janet_vm_stackn >= JANET_RECURSION_GUARD) {
janet_fiber_set_status(fiber, JANET_STATUS_ERROR);
*out = janet_cstringv("C stack recursed too deeply");
return JANET_SIGNAL_ERROR;
}
JanetFiberStatus startstatus = janet_fiber_status(fiber);
if (startstatus == JANET_STATUS_ALIVE ||
startstatus == JANET_STATUS_DEAD ||
startstatus == JANET_STATUS_ERROR) {
*out = janet_cstringv("cannot resume alive, dead, or errored fiber");
return JANET_SIGNAL_ERROR;
}
/* Prepare state */
janet_vm_stackn++;
janet_gcroot(janet_wrap_fiber(fiber));
JanetFiber *old_vm_fiber = janet_vm_fiber;
janet_vm_fiber = fiber;
janet_fiber_set_status(fiber, JANET_STATUS_ALIVE);
/* Run loop */
JanetSignal signal = run_vm(fiber, in);
/* Tear down */
janet_fiber_set_status(fiber, signal);
janet_vm_fiber = old_vm_fiber;
janet_vm_stackn--;
janet_gcunroot(janet_wrap_fiber(fiber));
/* Pop error or return value from fiber stack */
*out = fiber->data[--fiber->stacktop];
return signal;
}
JanetSignal janet_call(
JanetFunction *fun,
int32_t argn,
const Janet *argv,
Janet *out,
JanetFiber **f) {
JanetFiber *fiber = janet_fiber_n(fun, 64, argv, argn);
if (f) *f = fiber;
if (!fiber) {
*out = janet_cstringv("arity mismatch");
return JANET_SIGNAL_ERROR;
}
return janet_continue(fiber, janet_wrap_nil(), out);
}
/* Setup VM */
int janet_init(void) {
/* Garbage collection */
janet_vm_blocks = NULL;
janet_vm_next_collection = 0;
/* Setting memoryInterval to zero forces
* a collection pretty much every cycle, which is
* incredibly horrible for performance, but can help ensure
* there are no memory bugs during development */
janet_vm_gc_interval = 0x10000;
janet_symcache_init();
/* Initialize gc roots */
janet_vm_roots = NULL;
janet_vm_root_count = 0;
janet_vm_root_capacity = 0;
/* Initialize registry */
janet_vm_registry = janet_table(0);
janet_gcroot(janet_wrap_table(janet_vm_registry));
return 0;
}
/* Clear all memory associated with the VM */
void janet_deinit(void) {
janet_clear_memory();
janet_symcache_deinit();
free(janet_vm_roots);
janet_vm_roots = NULL;
janet_vm_root_count = 0;
janet_vm_root_capacity = 0;
janet_vm_registry = NULL;
}
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