diff options
| -rw-r--r-- | py/vm.c | 61 |
1 files changed, 23 insertions, 38 deletions
@@ -48,14 +48,6 @@ // 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 \ mp_uint_t unum = 0; \ do { \ @@ -613,29 +605,18 @@ dispatch_loop: mp_call_method_n_kw(3, 0, sp); SET_TOP(mp_const_none); } else if (MP_OBJ_IS_SMALL_INT(TOP())) { - mp_int_t cause_val = MP_OBJ_SMALL_INT_VALUE(TOP()); - if (cause_val == UNWIND_RETURN) { - // stack: (..., __exit__, ctx_mgr, ret_val, UNWIND_RETURN) - mp_obj_t ret_val = sp[-1]; - sp[-1] = mp_const_none; - sp[0] = mp_const_none; - sp[1] = mp_const_none; - mp_call_method_n_kw(3, 0, sp - 3); - sp[-3] = ret_val; - sp[-2] = MP_OBJ_NEW_SMALL_INT(UNWIND_RETURN); - } else { - assert(cause_val == UNWIND_JUMP); - // stack: (..., __exit__, ctx_mgr, dest_ip, num_exc, UNWIND_JUMP) - mp_obj_t dest_ip = sp[-2]; - mp_obj_t num_exc = sp[-1]; - sp[-2] = mp_const_none; - sp[-1] = mp_const_none; - sp[0] = mp_const_none; - mp_call_method_n_kw(3, 0, sp - 4); - sp[-4] = dest_ip; - sp[-3] = num_exc; - sp[-2] = MP_OBJ_NEW_SMALL_INT(UNWIND_JUMP); - } + // Getting here there are two distinct cases: + // - unwind return, stack: (..., __exit__, ctx_mgr, ret_val, SMALL_INT(-1)) + // - unwind jump, stack: (..., __exit__, ctx_mgr, dest_ip, SMALL_INT(num_exc)) + // For both cases we do exactly the same thing. + mp_obj_t data = sp[-1]; + mp_obj_t cause = sp[0]; + sp[-1] = mp_const_none; + sp[0] = mp_const_none; + sp[1] = mp_const_none; + mp_call_method_n_kw(3, 0, sp - 3); + sp[-3] = data; + sp[-2] = cause; sp -= 2; // we removed (__exit__, ctx_mgr) } else { assert(mp_obj_is_exception_instance(TOP())); @@ -680,10 +661,11 @@ unwind_jump:; // of a "with" block contains the context manager info. // 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 + // on the stack so it can return back to us when it is // done (when WITH_CLEANUP or END_FINALLY reached). - PUSH((mp_obj_t)unum); // push number of exception handlers left to unwind - PUSH(MP_OBJ_NEW_SMALL_INT(UNWIND_JUMP)); // push sentinel + // The sentinel is the number of exception handlers left to + // unwind, which is a non-negative integer. + PUSH(MP_OBJ_NEW_SMALL_INT(unum)); ip = exc_sp->handler; // get exception handler byte code address exc_sp--; // pop exception handler goto dispatch_loop; // run the exception handler @@ -720,11 +702,14 @@ unwind_jump:; } 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()); - if (reason == UNWIND_RETURN) { + mp_int_t cause = MP_OBJ_SMALL_INT_VALUE(POP()); + if (cause < 0) { + // A negative cause indicates unwind return goto unwind_return; } else { - assert(reason == UNWIND_JUMP); + // Otherwise it's an unwind jump and we must push as a raw + // number the number of exception handlers to unwind + PUSH((mp_obj_t)cause); goto unwind_jump; } } else { @@ -1101,7 +1086,7 @@ unwind_return: // (not calling it recursively). Set up a sentinel // on a stack so it can return back to us when it is // done (when WITH_CLEANUP or END_FINALLY reached). - PUSH(MP_OBJ_NEW_SMALL_INT(UNWIND_RETURN)); + PUSH(MP_OBJ_NEW_SMALL_INT(-1)); ip = exc_sp->handler; exc_sp--; goto dispatch_loop; |