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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 <dst/dst.h>
#include "opcodes.h"
/* VM State */
DstFiber *dst_vm_fiber;
/* Start running the VM from where it left off. */
int dst_continue() {
/* VM state */
DstValue *stack;
uint32_t *pc;
DstFunction *func;
/* 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 { dst_vm_fiber->ret = dst_wrap_string(dst_cstring((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(\
stack[oparg(2, 0xFF)].as.integer op stack[oparg(3, 0xFF)].as.integer\
);\
pc++;\
continue;
#define vm_binop_real(op)\
stack[oparg(1, 0xFF)] = dst_wrap_real(\
stack[oparg(2, 0xFF)].as.real op stack[oparg(3, 0xFF)].as.real\
);\
pc++;\
continue;
#define vm_binop_immediate(op)\
stack[oparg(1, 0xFF)] = dst_wrap_integer(\
stack[oparg(2, 0xFF)].as.integer op (*((int32_t *)pc) >> 24)\
);\
pc++;\
continue;
#define vm_binop(op)\
{\
DstValue op1 = stack[oparg(2, 0xFF)];\
DstValue op2 = stack[oparg(3, 0xFF)];\
vm_assert(op1.type == DST_INTEGER || op1.type == DST_REAL, "expected number");\
vm_assert(op2.type == DST_INTEGER || op2.type == DST_REAL, "expected number");\
stack[oparg(1, 0xFF)] = op1.type == DST_INTEGER\
? (op2.type == DST_INTEGER\
? dst_wrap_integer(op1.as.integer op op2.as.integer)\
: dst_wrap_real(dst_integer_to_real(op1.as.integer) op op2.as.real))\
: (op2.type == DST_INTEGER\
? dst_wrap_real(op1.as.real op dst_integer_to_real(op2.as.integer))\
: dst_wrap_real(op1.as.real op op2.as.real));\
pc++;\
continue;\
}
#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. It is large, but it is
* is maintainable. Adding new opcodes is mostly just adding newcases
* to this loop, adding the opcode to opcodes.h, and adding it to the assembler.
* Some opcodes, especially ones that do arithmetic, are almost entirely
* templated by the above macros. */
for (;;) {
switch (*pc & 0xFF) {
default:
vm_throw("unknown opcode");
break;
case DOP_NOOP:
pc++;
continue;
case DOP_ERROR:
dst_vm_fiber->ret = stack[oparg(1, 0xFF)];
goto vm_error;
case DOP_TYPECHECK:
vm_assert((1 << stack[oparg(1, 0xFF)].type) & oparg(2, 0xFFFF),
"typecheck failed");
pc++;
continue;
case DOP_RETURN:
dst_vm_fiber->ret = stack[oparg(1, 0xFFFFFF)];
goto vm_return;
case DOP_RETURN_NIL:
dst_vm_fiber->ret.type = DST_NIL;
goto vm_return;
case DOP_COERCE_INTEGER:
{
DstValue input = stack[oparg(2, 0xFFFF)];
if (input.type == DST_INTEGER) {
stack[oparg(1, 0xFF)] = input;
} else if (input.type == DST_REAL) {
stack[oparg(1, 0xFF)] = dst_wrap_integer(dst_real_to_integer(input.as.real));
} else {
vm_throw("expected number");
}
continue;
}
case DOP_COERCE_REAL:
{
DstValue input = stack[oparg(2, 0xFFFF)];
if (input.type == DST_INTEGER) {
stack[oparg(1, 0xFF)] = dst_wrap_real(dst_integer_to_real(input.as.integer));
} else if (input.type == DST_REAL) {
stack[oparg(1, 0xFF)] = input;
} else {
vm_throw("expected number");
}
continue;
}
case DOP_COERCE_STRING:
stack[oparg(1, 0xFF)] = dst_wrap_string(dst_to_string(stack[oparg(2, 0xFFFF)]));
pc++;
break;
case DOP_ADD_INTEGER:
vm_binop_integer(+);
case DOP_ADD_IMMEDIATE:
vm_binop_immediate(+);
case DOP_ADD_REAL:
vm_binop_real(+);
case DOP_ADD:
vm_binop(+);
case DOP_SUBTRACT_INTEGER:
vm_binop_integer(-);
case DOP_SUBTRACT_REAL:
vm_binop_real(-);
case DOP_SUBTRACT:
vm_binop(-);
case DOP_MULTIPLY_INTEGER:
vm_binop_integer(*);
case DOP_MULTIPLY_IMMEDIATE:
vm_binop_immediate(*);
case DOP_MULTIPLY_REAL:
vm_binop_real(*);
case DOP_MULTIPLY:
vm_binop(*);
case DOP_DIVIDE_INTEGER:
vm_assert(stack[oparg(3, 0xFF)].as.integer != 0, "integer divide by zero");
vm_assert(!(stack[oparg(3, 0xFF)].as.integer == -1 &&
stack[oparg(2, 0xFF)].as.integer == DST_INTEGER_MIN),
"integer divide overflow");
vm_binop_integer(/);
case DOP_DIVIDE_IMMEDIATE:
{
int64_t op1 = stack[oparg(2, 0xFF)].as.integer;
int64_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 by zero");
if (op2 == -1)
vm_throw("integer divide overflow");
else
stack[oparg(1, 0xFF)] = dst_wrap_integer(op1 / op2);
pc++;
continue;
}
case DOP_DIVIDE_REAL:
vm_binop_real(/);
case DOP_DIVIDE:
{
DstValue op1 = stack[oparg(2, 0xFF)];
DstValue op2 = stack[oparg(3, 0xFF)];
vm_assert(op1.type == DST_INTEGER || op1.type == DST_REAL, "expected number");
vm_assert(op2.type == DST_INTEGER || op2.type == DST_REAL, "expected number");
if (op2.type == DST_INTEGER && op2.as.integer == 0)
op2 = dst_wrap_real(0.0);
if (op2.type == DST_INTEGER && op2.as.integer == -1 &&
op1.type == DST_INTEGER && op1.as.integer == DST_INTEGER_MIN)
op2 = dst_wrap_real(-1);
stack[oparg(1, 0xFF)] = op1.type == DST_INTEGER
? op2.type == DST_INTEGER
? dst_wrap_integer(op1.as.integer / op2.as.integer)
: dst_wrap_real(dst_integer_to_real(op1.as.integer) / op2.as.real)
: op2.type == DST_INTEGER
? dst_wrap_real(op1.as.real / dst_integer_to_real(op2.as.integer))
: dst_wrap_real(op1.as.real / op2.as.real);
pc++;
continue;
}
case DOP_BAND:
vm_binop_integer(&);
case DOP_BOR:
vm_binop_integer(|);
case DOP_BXOR:
vm_binop_integer(^);
case DOP_BNOT:
stack[oparg(1, 0xFF)] = dst_wrap_integer(~stack[oparg(2, 0xFFFF)].as.integer);
continue;
case DOP_SHIFT_RIGHT_UNSIGNED:
stack[oparg(1, 0xFF)] = dst_wrap_integer(
stack[oparg(2, 0xFF)].as.uinteger
>>
stack[oparg(3, 0xFF)].as.uinteger
);
pc++;
continue;
case DOP_SHIFT_RIGHT_UNSIGNED_IMMEDIATE:
stack[oparg(1, 0xFF)] = dst_wrap_integer(
stack[oparg(2, 0xFF)].as.uinteger >> oparg(3, 0xFF)
);
pc++;
continue;
case DOP_SHIFT_RIGHT:
vm_binop_integer(>>);
case DOP_SHIFT_RIGHT_IMMEDIATE:
stack[oparg(1, 0xFF)] = dst_wrap_integer(
stack[oparg(2, 0xFF)].as.uinteger >> oparg(3, 0xFF)
);
pc++;
continue;
case DOP_SHIFT_LEFT:
vm_binop_integer(<<);
case DOP_MOVE:
stack[oparg(1, 0xFF)] = stack[oparg(2, 0xFFFF)];
pc++;
continue;
case DOP_JUMP:
pc += (*(int32_t *)pc) >> 8;
continue;
case DOP_JUMP_IF:
if (dst_truthy(stack[oparg(1, 0xFF)])) {
pc += (*(int32_t *)pc) >> 16;
} else {
pc++;
}
continue;
case DOP_GREATER_THAN:
stack[oparg(1, 0xFF)].type = DST_BOOLEAN;
stack[oparg(1, 0xFF)].as.boolean = dst_compare(
stack[oparg(2, 0xFF)],
stack[oparg(3 ,0xFF)]
) > 0;
pc++;
continue;
case DOP_EQUALS:
stack[oparg(1, 0xFF)].type = DST_BOOLEAN;
stack[oparg(1, 0xFF)].as.boolean = dst_equals(
stack[oparg(2, 0xFF)],
stack[oparg(3 ,0xFF)]
);
pc++;
continue;
case DOP_COMPARE:
stack[oparg(1, 0xFF)].type = DST_INTEGER;
stack[oparg(1, 0xFF)].as.integer = dst_compare(
stack[oparg(2, 0xFF)],
stack[oparg(3 ,0xFF)]
);
pc++;
continue;
case DOP_LOAD_NIL:
stack[oparg(1, 0xFFFFFF)].type = DST_NIL;
pc++;
continue;
case DOP_LOAD_BOOLEAN:
stack[oparg(1, 0xFF)] = dst_wrap_boolean(oparg(2, 0xFFFF));
pc++;
continue;
case DOP_LOAD_INTEGER:
stack[oparg(1, 0xFF)] = dst_wrap_integer(*((int32_t *)pc) >> 16);
pc++;
continue;
case DOP_LOAD_CONSTANT:
vm_assert(oparg(2, 0xFFFF) < func->def->constants_length, "invalid constant");
stack[oparg(1, 0xFF)] = func->def->constants[oparg(2, 0xFFFF)];
pc++;
continue;
case DOP_LOAD_UPVALUE:
{
uint32_t eindex = oparg(2, 0xFF);
uint32_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++;
continue;
}
case DOP_SET_UPVALUE:
{
uint32_t eindex = oparg(2, 0xFF);
uint32_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++;
continue;
}
case DOP_CLOSURE:
{
uint32_t i;
DstFunction *fn;
DstFuncDef *fd;
vm_assert(oparg(2, 0xFFFF) < func->def->constants_length, "invalid constant");
vm_assert(func->def->constants[oparg(2, 0xFFFF)].type == DST_NIL, "constant must be funcdef");
fd = (DstFuncDef *)(func->def->constants[oparg(2, 0xFFFF)].as.pointer);
fn = dst_alloc(DST_MEMORY_FUNCTION, sizeof(DstFunction));
fn->envs = malloc(sizeof(DstFuncEnv *) * fd->environments_length);
if (NULL == fn->envs) {
DST_OUT_OF_MEMORY;
}
if (fd->flags & DST_FUNCDEF_FLAG_NEEDSENV) {
/* Delayed capture of current stack frame */
DstFuncEnv *env = dst_alloc(DST_MEMORY_FUNCENV, sizeof(DstFuncEnv));
env->offset = dst_vm_fiber->frame;
env->as.fiber = dst_vm_fiber;
env->length = func->def->slotcount;
fn->envs[0] = env;
} else {
fn->envs[0] = NULL;
}
for (i = 1; i < fd->environments_length; ++i) {
uint32_t inherit = fd->environments[i];
fn->envs[i] = func->envs[inherit];
}
stack[oparg(1, 0xFF)] = dst_wrap_function(fn);
pc++;
break;
}
case DOP_PUSH:
dst_fiber_push(dst_vm_fiber, stack[oparg(1, 0xFFFFFF)]);
pc++;
break;
case DOP_PUSH_2:
dst_fiber_push2(dst_vm_fiber,
stack[oparg(1, 0xFF)],
stack[oparg(2, 0xFFFF)]);
pc++;
break;;
case DOP_PUSH_3:
dst_fiber_push3(dst_vm_fiber,
stack[oparg(1, 0xFF)],
stack[oparg(2, 0xFF)],
stack[oparg(3, 0xFF)]);
pc++;
break;
case DOP_PUSH_ARRAY:
{
uint32_t count;
const DstValue *array;
if (dst_seq_view(stack[oparg(1, 0xFFFFFF)], &array, &count)) {
dst_fiber_pushn(dst_vm_fiber, array, count);
} else {
vm_throw("expected array or tuple");
}
pc++;
break;
}
case DOP_CALL:
{
DstValue callee = stack[oparg(2, 0xFFFF)];
if (callee.type == DST_FUNCTION) {
func = callee.as.function;
dst_fiber_funcframe(dst_vm_fiber, func);
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
pc = func->def->bytecode;
break;
} else if (callee.type == DST_CFUNCTION) {
dst_fiber_cframe(dst_vm_fiber);
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
dst_vm_fiber->ret.type = DST_NIL;
if (callee.as.cfunction(stack, dst_vm_fiber->frametop - dst_vm_fiber->frame)) {
dst_fiber_popframe(dst_vm_fiber);
goto vm_error;
} else {
dst_fiber_popframe(dst_vm_fiber);
goto vm_return;
}
} else {
vm_throw("cannot call non-function type");
}
break;
}
case DOP_TAILCALL:
{
DstValue callee = stack[oparg(2, 0xFFFF)];
if (callee.type == DST_FUNCTION) {
func = callee.as.function;
dst_fiber_funcframe_tail(dst_vm_fiber, func);
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
pc = func->def->bytecode;
break;
} else if (callee.type == DST_CFUNCTION) {
dst_fiber_cframe_tail(dst_vm_fiber);
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
dst_vm_fiber->ret.type = DST_NIL;
if (callee.as.cfunction(stack, dst_vm_fiber->frametop - dst_vm_fiber->frame)) {
dst_fiber_popframe(dst_vm_fiber);
goto vm_error;
} else {
dst_fiber_popframe(dst_vm_fiber);
goto vm_return;
}
} else {
vm_throw("expected function");
}
break;
}
case DOP_SYSCALL:
{
DstCFunction f = dst_vm_syscalls[oparg(2, 0xFF)];
vm_assert(NULL != f, "invalid syscall");
dst_fiber_cframe(dst_vm_fiber);
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
dst_vm_fiber->ret.type = DST_NIL;
if (f(stack, dst_vm_fiber->frametop - dst_vm_fiber->frame)) {
dst_fiber_popframe(dst_vm_fiber);
goto vm_error;
} else {
dst_fiber_popframe(dst_vm_fiber);
goto vm_return;
}
continue;
}
case DOP_LOAD_SYSCALL:
{
DstCFunction f = dst_vm_syscalls[oparg(2, 0xFF)];
vm_assert(NULL != f, "invalid syscall");
stack[oparg(1, 0xFF)] = dst_wrap_cfunction(f);
pc++;
continue;
}
case DOP_TRANSFER:
{
DstFiber *nextfiber;
DstStackFrame *frame = dst_stack_frame(stack);
DstValue temp = stack[oparg(2, 0xFF)];
DstValue retvalue = stack[oparg(3, 0xFF)];
vm_assert(temp.type == DST_FIBER ||
temp.type == DST_NIL, "expected fiber");
nextfiber = temp.type == DST_FIBER
? temp.as.fiber
: dst_vm_fiber->parent;
/* Check for root fiber */
if (NULL == nextfiber) {
frame->pc = pc;
dst_vm_fiber->ret = retvalue;
return 0;
}
vm_assert(nextfiber->status == DST_FIBER_PENDING, "can only transfer to pending fiber");
frame->pc = pc;
dst_vm_fiber->status = DST_FIBER_PENDING;
dst_vm_fiber = nextfiber;
vm_init_fiber_state();
stack[oparg(1, 0xFF)] = retvalue;
pc++;
continue;
}
/* Handle returning from stack frame. Expect return value in fiber->ret */
vm_return:
{
DstValue ret = dst_vm_fiber->ret;
dst_fiber_popframe(dst_vm_fiber);
while (!dst_vm_fiber->frame ||
dst_vm_fiber->status == DST_FIBER_DEAD ||
dst_vm_fiber->status == DST_FIBER_ERROR) {
dst_vm_fiber->status = DST_FIBER_DEAD;
if (NULL != dst_vm_fiber->parent) {
dst_vm_fiber = dst_vm_fiber->parent;
if (dst_vm_fiber->status == DST_FIBER_ALIVE) {
/* If the parent thread is still alive,
we are inside a cfunction */
return 0;
}
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
} else {
return 0;
}
}
dst_vm_fiber->status = DST_FIBER_ALIVE;
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
pc = dst_stack_frame(stack)->pc;
stack[oparg(1, 0xFF)] = ret;
pc++;
continue;
}
/* Handle errors from c functions and vm opcodes */
vm_error:
{
DstValue ret = dst_vm_fiber->ret;
dst_vm_fiber->status = DST_FIBER_ERROR;
while (!dst_vm_fiber->frame ||
dst_vm_fiber->status == DST_FIBER_DEAD ||
dst_vm_fiber->status == DST_FIBER_ERROR) {
if (dst_vm_fiber->parent == NULL)
return 1;
dst_vm_fiber = dst_vm_fiber->parent;
if (dst_vm_fiber->status == DST_FIBER_ALIVE) {
/* If the parent thread is still alive,
we are inside a cfunction */
return 1;
}
}
dst_vm_fiber->status = DST_FIBER_ALIVE;
stack = dst_vm_fiber->data + dst_vm_fiber->frame;
pc = dst_stack_frame(stack)->pc;
stack[oparg(1, 0xFF)] = ret;
pc++;
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 */
dst_maybe_collect();
} /* end for */
#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(DstValue callee) {
if (NULL == dst_vm_fiber) {
dst_vm_fiber = dst_fiber(0);
} else {
dst_fiber_reset(dst_vm_fiber);
}
if (callee.type == DST_CFUNCTION) {
dst_vm_fiber->ret.type = DST_NIL;
dst_fiber_cframe(dst_vm_fiber);
return callee.as.cfunction(dst_vm_fiber->data + dst_vm_fiber->frame, 0);
} else if (callee.type == DST_FUNCTION) {
dst_fiber_funcframe(dst_vm_fiber, callee.as.function);
return dst_continue();
}
dst_vm_fiber->ret = dst_wrap_string(dst_cstring("expected function"));
return 1;
}
/* 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_memory_interval = 0;
uint32_t initialCacheCapacity = 1024;
/* Set up the cache */
dst_vm_cache = calloc(1, initialCacheCapacity * sizeof(DstValue));
if (NULL == dst_vm_cache) {
return 1;
}
dst_vm_cache_capacity = dst_vm_cache == NULL ? 0 : initialCacheCapacity;
dst_vm_cache_count = 0;
dst_vm_cache_deleted = 0;
/* Set thread */
dst_vm_fiber = NULL;
return 0;
}
/* Clear all memory associated with the VM */
void dst_deinit() {
dst_clear_memory();
dst_vm_fiber = NULL;
/* Deinit the cache */
free(dst_vm_cache);
dst_vm_cache = NULL;
dst_vm_cache_count = 0;
dst_vm_cache_capacity = 0;
dst_vm_cache_deleted = 0;
}
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