circuitpython/py/vm.c
Damien George bee17b00e3 py: Put n_state for bytecode in the bytecode prelude.
Rationale: setting up the stack (state for locals and exceptions) is
really part of the "code", it's the prelude of the function.  For
example, native code adjusts the stack pointer on entry to the function.
Native code doesn't need to know n_state for any other reason.  So
putting the state size in the bytecode prelude is sensible.

It reduced ROM usage on STM by about 30 bytes :)  And makes it easier to
pass information about the bytecode between functions.
2014-03-27 11:07:04 +00:00

727 lines
29 KiB
C

#include <stdio.h>
#include <assert.h>
#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
#include "bc0.h"
#include "bc.h"
// Value stack grows up (this makes it incompatible with native C stack, but
// makes sure that arguments to functions are in natural order arg1..argN
// (Python semantics mandates left-to-right evaluation order, including for
// function arguments). Stack pointer is pre-incremented and points at the
// top element.
// Exception stack also grows up, top element is also pointed at.
// Exception stack unwind reasons (WHY_* in CPython-speak)
// TODO perhaps compress this to RETURN=0, JUMP>0, with number of unwinds
// left to do encoded in the JUMP number
typedef enum {
UNWIND_RETURN = 1,
UNWIND_JUMP,
} mp_unwind_reason_t;
#define DECODE_UINT { \
unum = 0; \
do { \
unum = (unum << 7) + (*ip & 0x7f); \
} while ((*ip++ & 0x80) != 0); \
}
#define DECODE_ULABEL do { unum = (ip[0] | (ip[1] << 8)); ip += 2; } while (0)
#define DECODE_SLABEL do { unum = (ip[0] | (ip[1] << 8)) - 0x8000; ip += 2; } while (0)
#define DECODE_QSTR { \
qst = 0; \
do { \
qst = (qst << 7) + (*ip & 0x7f); \
} while ((*ip++ & 0x80) != 0); \
}
#define PUSH(val) *++sp = (val)
#define POP() (*sp--)
#define TOP() (*sp)
#define SET_TOP(val) *sp = (val)
mp_vm_return_kind_t mp_execute_byte_code(const byte *code, const mp_obj_t *args, uint n_args, const mp_obj_t *args2, uint n_args2, mp_obj_t *ret) {
const byte *ip = code;
// get code info size, and skip line number table
machine_uint_t code_info_size = ip[0] | (ip[1] << 8) | (ip[2] << 16) | (ip[3] << 24);
ip += code_info_size;
// bytecode prelude: state size and exception stack size; 16 bit uints
machine_uint_t n_state = ip[0] | (ip[1] << 8);
machine_uint_t n_exc_stack = ip[2] | (ip[3] << 8);
ip += 4;
// allocate state for locals and stack
mp_obj_t temp_state[10];
mp_obj_t *state = &temp_state[0];
if (n_state > 10) {
state = m_new(mp_obj_t, n_state);
}
mp_obj_t *sp = &state[0] - 1;
// allocate state for exceptions
mp_exc_stack exc_state[4];
mp_exc_stack *exc_stack = &exc_state[0];
if (n_exc_stack > 4) {
exc_stack = m_new(mp_exc_stack, n_exc_stack);
}
mp_exc_stack *exc_sp = &exc_stack[0] - 1;
// init args
for (uint i = 0; i < n_args; i++) {
state[n_state - 1 - i] = args[i];
}
for (uint i = 0; i < n_args2; i++) {
state[n_state - 1 - n_args - i] = args2[i];
}
// bytecode prelude: initialise closed over variables
for (uint n_local = *ip++; n_local > 0; n_local--) {
uint local_num = *ip++;
if (local_num < n_args + n_args2) {
state[n_state - 1 - local_num] = mp_obj_new_cell(state[n_state - 1 - local_num]);
} else {
state[n_state - 1 - local_num] = mp_obj_new_cell(MP_OBJ_NULL);
}
}
// execute the byte code
mp_vm_return_kind_t vm_return_kind = mp_execute_byte_code_2(code, &ip, &state[n_state - 1], &sp, exc_stack, &exc_sp, MP_OBJ_NULL);
switch (vm_return_kind) {
case MP_VM_RETURN_NORMAL:
*ret = *sp;
return MP_VM_RETURN_NORMAL;
case MP_VM_RETURN_EXCEPTION:
*ret = state[n_state - 1];
return MP_VM_RETURN_EXCEPTION;
case MP_VM_RETURN_YIELD: // byte-code shouldn't yield
default:
assert(0);
*ret = mp_const_none;
return MP_VM_RETURN_NORMAL;
}
}
// fastn has items in reverse order (fastn[0] is local[0], fastn[-1] is local[1], etc)
// sp points to bottom of stack which grows up
// returns:
// MP_VM_RETURN_NORMAL, sp valid, return value in *sp
// MP_VM_RETURN_YIELD, ip, sp valid, yielded value in *sp
// MP_VM_RETURN_EXCEPTION, exception in fastn[0]
mp_vm_return_kind_t mp_execute_byte_code_2(const byte *code_info, const byte **ip_in_out,
mp_obj_t *fastn, mp_obj_t **sp_in_out,
mp_exc_stack *exc_stack, mp_exc_stack **exc_sp_in_out,
volatile mp_obj_t inject_exc) {
// careful: be sure to declare volatile any variables read in the exception handler (written is ok, I think)
const byte *ip = *ip_in_out;
mp_obj_t *sp = *sp_in_out;
machine_uint_t unum;
qstr qst;
mp_obj_t obj1, obj2;
nlr_buf_t nlr;
volatile bool currently_in_except_block = MP_TAGPTR_TAG(*exc_sp_in_out); // 0 or 1, to detect nested exceptions
mp_exc_stack *volatile exc_sp = MP_TAGPTR_PTR(*exc_sp_in_out); // stack grows up, exc_sp points to top of stack
const byte *volatile save_ip = ip; // this is so we can access ip in the exception handler without making ip volatile (which means the compiler can't keep it in a register in the main loop)
// outer exception handling loop
for (;;) {
outer_dispatch_loop:
if (nlr_push(&nlr) == 0) {
// If we have exception to inject, now that we finish setting up
// execution context, raise it. This works as if RAISE_VARARGS
// bytecode was executed.
if (inject_exc != MP_OBJ_NULL) {
mp_obj_t t = inject_exc;
inject_exc = MP_OBJ_NULL;
nlr_jump(rt_make_raise_obj(t));
}
// loop to execute byte code
for (;;) {
dispatch_loop:
save_ip = ip;
int op = *ip++;
switch (op) {
case MP_BC_LOAD_CONST_FALSE:
PUSH(mp_const_false);
break;
case MP_BC_LOAD_CONST_NONE:
PUSH(mp_const_none);
break;
case MP_BC_LOAD_CONST_TRUE:
PUSH(mp_const_true);
break;
case MP_BC_LOAD_CONST_ELLIPSIS:
PUSH(mp_const_ellipsis);
break;
case MP_BC_LOAD_CONST_SMALL_INT: {
machine_int_t num = 0;
if ((ip[0] & 0x40) != 0) {
// Number is negative
num--;
}
do {
num = (num << 7) | (*ip & 0x7f);
} while ((*ip++ & 0x80) != 0);
PUSH(MP_OBJ_NEW_SMALL_INT(num));
break;
}
case MP_BC_LOAD_CONST_INT:
DECODE_QSTR;
PUSH(mp_obj_new_int_from_long_str(qstr_str(qst)));
break;
case MP_BC_LOAD_CONST_DEC:
DECODE_QSTR;
PUSH(rt_load_const_dec(qst));
break;
case MP_BC_LOAD_CONST_ID:
DECODE_QSTR;
PUSH(rt_load_const_str(qst)); // TODO
break;
case MP_BC_LOAD_CONST_BYTES:
DECODE_QSTR;
PUSH(rt_load_const_bytes(qst));
break;
case MP_BC_LOAD_CONST_STRING:
DECODE_QSTR;
PUSH(rt_load_const_str(qst));
break;
case MP_BC_LOAD_FAST_0:
PUSH(fastn[0]);
break;
case MP_BC_LOAD_FAST_1:
PUSH(fastn[-1]);
break;
case MP_BC_LOAD_FAST_2:
PUSH(fastn[-2]);
break;
case MP_BC_LOAD_FAST_N:
DECODE_UINT;
PUSH(fastn[-unum]);
break;
case MP_BC_LOAD_DEREF:
DECODE_UINT;
PUSH(rt_get_cell(fastn[-unum]));
break;
case MP_BC_LOAD_NAME:
DECODE_QSTR;
PUSH(rt_load_name(qst));
break;
case MP_BC_LOAD_GLOBAL:
DECODE_QSTR;
PUSH(rt_load_global(qst));
break;
case MP_BC_LOAD_ATTR:
DECODE_QSTR;
SET_TOP(rt_load_attr(TOP(), qst));
break;
case MP_BC_LOAD_METHOD:
DECODE_QSTR;
rt_load_method(*sp, qst, sp);
sp += 1;
break;
case MP_BC_LOAD_BUILD_CLASS:
PUSH(rt_load_build_class());
break;
case MP_BC_STORE_FAST_0:
fastn[0] = POP();
break;
case MP_BC_STORE_FAST_1:
fastn[-1] = POP();
break;
case MP_BC_STORE_FAST_2:
fastn[-2] = POP();
break;
case MP_BC_STORE_FAST_N:
DECODE_UINT;
fastn[-unum] = POP();
break;
case MP_BC_STORE_DEREF:
DECODE_UINT;
rt_set_cell(fastn[-unum], POP());
break;
case MP_BC_STORE_NAME:
DECODE_QSTR;
rt_store_name(qst, POP());
break;
case MP_BC_STORE_GLOBAL:
DECODE_QSTR;
rt_store_global(qst, POP());
break;
case MP_BC_STORE_ATTR:
DECODE_QSTR;
rt_store_attr(sp[0], qst, sp[-1]);
sp -= 2;
break;
case MP_BC_STORE_SUBSCR:
rt_store_subscr(sp[-1], sp[0], sp[-2]);
sp -= 3;
break;
case MP_BC_DELETE_NAME:
DECODE_QSTR;
rt_delete_name(qst);
break;
case MP_BC_DUP_TOP:
obj1 = TOP();
PUSH(obj1);
break;
case MP_BC_DUP_TOP_TWO:
sp += 2;
sp[0] = sp[-2];
sp[-1] = sp[-3];
break;
case MP_BC_POP_TOP:
sp -= 1;
break;
case MP_BC_ROT_TWO:
obj1 = sp[0];
sp[0] = sp[-1];
sp[-1] = obj1;
break;
case MP_BC_ROT_THREE:
obj1 = sp[0];
sp[0] = sp[-1];
sp[-1] = sp[-2];
sp[-2] = obj1;
break;
case MP_BC_JUMP:
DECODE_SLABEL;
ip += unum;
break;
case MP_BC_POP_JUMP_IF_TRUE:
DECODE_SLABEL;
if (rt_is_true(POP())) {
ip += unum;
}
break;
case MP_BC_POP_JUMP_IF_FALSE:
DECODE_SLABEL;
if (!rt_is_true(POP())) {
ip += unum;
}
break;
case MP_BC_JUMP_IF_TRUE_OR_POP:
DECODE_SLABEL;
if (rt_is_true(TOP())) {
ip += unum;
} else {
sp--;
}
break;
case MP_BC_JUMP_IF_FALSE_OR_POP:
DECODE_SLABEL;
if (rt_is_true(TOP())) {
sp--;
} else {
ip += unum;
}
break;
/* we are trying to get away without using this opcode
case MP_BC_SETUP_LOOP:
DECODE_UINT;
// push_block(MP_BC_SETUP_LOOP, ip + unum, sp)
break;
*/
case MP_BC_UNWIND_JUMP:
DECODE_SLABEL;
PUSH((void*)(ip + unum)); // push destination ip for jump
PUSH((void*)(machine_uint_t)(*ip)); // push number of exception handlers to unwind
unwind_jump:
unum = (machine_uint_t)POP(); // get number of exception handlers to unwind
while (unum > 0) {
unum -= 1;
assert(exc_sp >= exc_stack);
if (exc_sp->opcode == MP_BC_SETUP_FINALLY) {
// We're going to run "finally" code as a coroutine
// (not calling it recursively). Set up a sentinel
// on a stack so it can return back to us when it is
// done (when END_FINALLY reached).
PUSH((void*)unum); // push number of exception handlers left to unwind
PUSH(MP_OBJ_NEW_SMALL_INT(UNWIND_JUMP)); // push sentinel
ip = exc_sp->handler; // get exception handler byte code address
exc_sp--; // pop exception handler
goto dispatch_loop; // run the exception handler
}
exc_sp--;
}
ip = (const byte*)POP(); // pop destination ip for jump
break;
// matched against: POP_BLOCK or POP_EXCEPT (anything else?)
case MP_BC_SETUP_EXCEPT:
case MP_BC_SETUP_FINALLY:
DECODE_ULABEL; // except labels are always forward
++exc_sp;
exc_sp->opcode = op;
exc_sp->handler = ip + unum;
exc_sp->val_sp = MP_TAGPTR_MAKE(sp, currently_in_except_block);
currently_in_except_block = 0; // in a try block now
break;
case MP_BC_END_FINALLY:
// not fully implemented
// if TOS is an exception, reraises the exception (3 values on TOS)
// if TOS is None, just pops it and continues
// if TOS is an integer, does something else
// else error
if (mp_obj_is_exception_instance(TOP())) {
nlr_jump(TOP());
}
if (TOP() == mp_const_none) {
sp--;
} else if (MP_OBJ_IS_SMALL_INT(TOP())) {
// We finished "finally" coroutine and now dispatch back
// to our caller, based on TOS value
mp_unwind_reason_t reason = MP_OBJ_SMALL_INT_VALUE(POP());
switch (reason) {
case UNWIND_RETURN:
goto unwind_return;
case UNWIND_JUMP:
goto unwind_jump;
}
assert(0);
} else {
assert(0);
}
break;
case MP_BC_GET_ITER:
SET_TOP(rt_getiter(TOP()));
break;
case MP_BC_FOR_ITER:
DECODE_ULABEL; // the jump offset if iteration finishes; for labels are always forward
obj1 = rt_iternext_allow_raise(TOP());
if (obj1 == MP_OBJ_NULL) {
--sp; // pop the exhausted iterator
ip += unum; // jump to after for-block
} else {
PUSH(obj1); // push the next iteration value
}
break;
// matched against: SETUP_EXCEPT, SETUP_FINALLY, SETUP_WITH
case MP_BC_POP_BLOCK:
// we are exiting an exception handler, so pop the last one of the exception-stack
assert(exc_sp >= exc_stack);
currently_in_except_block = MP_TAGPTR_TAG(exc_sp->val_sp); // restore previous state
exc_sp--; // pop back to previous exception handler
break;
// matched against: SETUP_EXCEPT
case MP_BC_POP_EXCEPT:
// TODO need to work out how blocks work etc
// pops block, checks it's an exception block, and restores the stack, saving the 3 exception values to local threadstate
assert(exc_sp >= exc_stack);
assert(currently_in_except_block);
//sp = (mp_obj_t*)(*exc_sp--);
//exc_sp--; // discard ip
currently_in_except_block = MP_TAGPTR_TAG(exc_sp->val_sp); // restore previous state
exc_sp--; // pop back to previous exception handler
//sp -= 3; // pop 3 exception values
break;
case MP_BC_NOT:
if (TOP() == mp_const_true) {
SET_TOP(mp_const_false);
} else {
SET_TOP(mp_const_true);
}
break;
case MP_BC_UNARY_OP:
unum = *ip++;
SET_TOP(rt_unary_op(unum, TOP()));
break;
case MP_BC_BINARY_OP:
unum = *ip++;
obj2 = POP();
obj1 = TOP();
SET_TOP(rt_binary_op(unum, obj1, obj2));
break;
case MP_BC_BUILD_TUPLE:
DECODE_UINT;
sp -= unum - 1;
SET_TOP(rt_build_tuple(unum, sp));
break;
case MP_BC_BUILD_LIST:
DECODE_UINT;
sp -= unum - 1;
SET_TOP(rt_build_list(unum, sp));
break;
case MP_BC_LIST_APPEND:
DECODE_UINT;
// I think it's guaranteed by the compiler that sp[unum] is a list
rt_list_append(sp[-unum], sp[0]);
sp--;
break;
case MP_BC_BUILD_MAP:
DECODE_UINT;
PUSH(rt_build_map(unum));
break;
case MP_BC_STORE_MAP:
sp -= 2;
rt_store_map(sp[0], sp[2], sp[1]);
break;
case MP_BC_MAP_ADD:
DECODE_UINT;
// I think it's guaranteed by the compiler that sp[-unum - 1] is a map
rt_store_map(sp[-unum - 1], sp[0], sp[-1]);
sp -= 2;
break;
case MP_BC_BUILD_SET:
DECODE_UINT;
sp -= unum - 1;
SET_TOP(rt_build_set(unum, sp));
break;
case MP_BC_SET_ADD:
DECODE_UINT;
// I think it's guaranteed by the compiler that sp[-unum] is a set
rt_store_set(sp[-unum], sp[0]);
sp--;
break;
#if MICROPY_ENABLE_SLICE
case MP_BC_BUILD_SLICE:
DECODE_UINT;
if (unum == 2) {
obj2 = POP();
obj1 = TOP();
SET_TOP(mp_obj_new_slice(obj1, obj2, NULL));
} else {
printf("3-argument slice is not supported\n");
assert(0);
}
break;
#endif
case MP_BC_UNPACK_SEQUENCE:
DECODE_UINT;
rt_unpack_sequence(sp[0], unum, sp);
sp += unum - 1;
break;
case MP_BC_MAKE_FUNCTION:
DECODE_UINT;
PUSH(rt_make_function_from_id(unum, MP_OBJ_NULL));
break;
case MP_BC_MAKE_FUNCTION_DEFARGS:
DECODE_UINT;
SET_TOP(rt_make_function_from_id(unum, TOP()));
break;
case MP_BC_MAKE_CLOSURE:
DECODE_UINT;
SET_TOP(rt_make_closure_from_id(unum, TOP(), MP_OBJ_NULL));
break;
case MP_BC_MAKE_CLOSURE_DEFARGS:
DECODE_UINT;
obj1 = POP();
SET_TOP(rt_make_closure_from_id(unum, obj1, TOP()));
break;
case MP_BC_CALL_FUNCTION:
DECODE_UINT;
// unum & 0xff == n_positional
// (unum >> 8) & 0xff == n_keyword
sp -= (unum & 0xff) + ((unum >> 7) & 0x1fe);
SET_TOP(rt_call_function_n_kw(*sp, unum & 0xff, (unum >> 8) & 0xff, sp + 1));
break;
case MP_BC_CALL_METHOD:
DECODE_UINT;
// unum & 0xff == n_positional
// (unum >> 8) & 0xff == n_keyword
sp -= (unum & 0xff) + ((unum >> 7) & 0x1fe) + 1;
SET_TOP(rt_call_method_n_kw(unum & 0xff, (unum >> 8) & 0xff, sp));
break;
case MP_BC_RETURN_VALUE:
unwind_return:
while (exc_sp >= exc_stack) {
if (exc_sp->opcode == MP_BC_SETUP_FINALLY) {
// We're going to run "finally" code as a coroutine
// (not calling it recursively). Set up a sentinel
// on a stack so it can return back to us when it is
// done (when END_FINALLY reached).
PUSH(MP_OBJ_NEW_SMALL_INT(UNWIND_RETURN));
ip = exc_sp->handler;
// We don't need to do anything with sp, finally is just
// syntactic sugar for sequential execution??
// sp =
exc_sp--;
goto dispatch_loop;
}
exc_sp--;
}
nlr_pop();
*sp_in_out = sp;
assert(exc_sp == exc_stack - 1);
return MP_VM_RETURN_NORMAL;
case MP_BC_RAISE_VARARGS:
unum = *ip++;
assert(unum <= 1);
if (unum == 0) {
// This assumes that nlr.ret_val holds last raised
// exception and is not overwritten since then.
obj1 = nlr.ret_val;
} else {
obj1 = POP();
}
nlr_jump(rt_make_raise_obj(obj1));
case MP_BC_YIELD_VALUE:
nlr_pop();
*ip_in_out = ip;
*sp_in_out = sp;
*exc_sp_in_out = MP_TAGPTR_MAKE(exc_sp, currently_in_except_block);
return MP_VM_RETURN_YIELD;
case MP_BC_IMPORT_NAME:
DECODE_QSTR;
obj1 = POP();
SET_TOP(rt_import_name(qst, obj1, TOP()));
break;
case MP_BC_IMPORT_FROM:
DECODE_QSTR;
obj1 = rt_import_from(TOP(), qst);
PUSH(obj1);
break;
case MP_BC_IMPORT_STAR:
rt_import_all(POP());
break;
default:
printf("code %p, byte code 0x%02x not implemented\n", ip, op);
assert(0);
nlr_pop();
return MP_VM_RETURN_NORMAL;
}
}
} else {
// exception occurred
// check if it's a StopIteration within a for block
if (*save_ip == MP_BC_FOR_ITER && mp_obj_is_subclass_fast(mp_obj_get_type(nlr.ret_val), &mp_type_StopIteration)) {
ip = save_ip + 1;
DECODE_ULABEL; // the jump offset if iteration finishes; for labels are always forward
--sp; // pop the exhausted iterator
ip += unum; // jump to after for-block
goto outer_dispatch_loop; // continue with dispatch loop
}
// set file and line number that the exception occurred at
// TODO: don't set traceback for exceptions re-raised by END_FINALLY.
// But consider how to handle nested exceptions.
if (mp_obj_is_exception_instance(nlr.ret_val)) {
machine_uint_t code_info_size = code_info[0] | (code_info[1] << 8) | (code_info[2] << 16) | (code_info[3] << 24);
qstr source_file = code_info[4] | (code_info[5] << 8) | (code_info[6] << 16) | (code_info[7] << 24);
qstr block_name = code_info[8] | (code_info[9] << 8) | (code_info[10] << 16) | (code_info[11] << 24);
machine_uint_t source_line = 1;
machine_uint_t bc = save_ip - code_info - code_info_size;
//printf("find %lu %d %d\n", bc, code_info[12], code_info[13]);
for (const byte* ci = code_info + 12; *ci && bc >= ((*ci) & 31); ci++) {
bc -= *ci & 31;
source_line += *ci >> 5;
}
mp_obj_exception_add_traceback(nlr.ret_val, source_file, source_line, block_name);
}
while (currently_in_except_block) {
// nested exception
assert(exc_sp >= exc_stack);
// TODO make a proper message for nested exception
// at the moment we are just raising the very last exception (the one that caused the nested exception)
// move up to previous exception handler
currently_in_except_block = MP_TAGPTR_TAG(exc_sp->val_sp); // restore previous state
exc_sp--; // pop back to previous exception handler
}
if (exc_sp >= exc_stack) {
// set flag to indicate that we are now handling an exception
currently_in_except_block = 1;
// catch exception and pass to byte code
sp = MP_TAGPTR_PTR(exc_sp->val_sp);
ip = exc_sp->handler;
// push(traceback, exc-val, exc-type)
PUSH(mp_const_none);
PUSH(nlr.ret_val);
PUSH(nlr.ret_val); // TODO should be type(nlr.ret_val), I think...
} else {
// propagate exception to higher level
// TODO what to do about ip and sp? they don't really make sense at this point
fastn[0] = nlr.ret_val; // must put exception here because sp is invalid
return MP_VM_RETURN_EXCEPTION;
}
}
}
}