py: VM never throws an exception, instead returns a status and value.
Addresses issue #290, and hopefully sets up things to allow generators
throwing exceptions, etc.
diff --git a/py/vm.c b/py/vm.c
index 461fecb..573167b 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -47,7 +47,7 @@
#define TOP() (*sp)
#define SET_TOP(val) *sp = (val)
-mp_obj_t mp_execute_byte_code(const byte *code, const mp_obj_t *args, uint n_args, const mp_obj_t *args2, uint n_args2, uint n_state) {
+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, uint n_state, mp_obj_t *ret) {
// allocate state for locals and stack
mp_obj_t temp_state[10];
mp_obj_t *state = &temp_state[0];
@@ -83,20 +83,30 @@
}
// execute the byte code
- if (mp_execute_byte_code_2(code, &ip, &state[n_state - 1], &sp)) {
- // it shouldn't yield
- assert(0);
- }
+ mp_vm_return_kind_t vm_return_kind = mp_execute_byte_code_2(code, &ip, &state[n_state - 1], &sp);
- // TODO check fails if, eg, return from within for loop
- //assert(sp == &state[17]);
- return *sp;
+ 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 true if bytecode yielded
-bool mp_execute_byte_code_2(const byte *code_info, const byte **ip_in_out, mp_obj_t *fastn, mp_obj_t **sp_in_out) {
+// 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) {
// careful: be sure to declare volatile any variables read in the exception handler (written is ok, I think)
const byte *ip = *ip_in_out;
@@ -569,7 +579,7 @@
nlr_pop();
*sp_in_out = sp;
assert(exc_sp == &exc_stack[0] - 1);
- return false;
+ return MP_VM_RETURN_NORMAL;
case MP_BC_RAISE_VARARGS:
unum = *ip++;
@@ -581,7 +591,7 @@
nlr_pop();
*ip_in_out = ip;
*sp_in_out = sp;
- return true;
+ return MP_VM_RETURN_YIELD;
case MP_BC_IMPORT_NAME:
DECODE_QSTR;
@@ -603,7 +613,7 @@
printf("code %p, byte code 0x%02x not implemented\n", ip, op);
assert(0);
nlr_pop();
- return false;
+ return MP_VM_RETURN_NORMAL;
}
}
@@ -653,9 +663,10 @@
PUSH(nlr.ret_val); // TODO should be type(nlr.ret_val), I think...
} else {
- // re-raise exception to higher level
- // TODO what to do if this is a generator??
- nlr_jump(nlr.ret_val);
+ // 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;
}
}
}