py: Implement proper re-raising in native codegen's finally handler.

This allows an exception to propagate correctly through a finally
handler.

py/emitnative.c

@@ -1824,7 +1824,14 @@ STATIC void emit_native_setup_finally(emit_t *emit, mp_uint_t label) {
 }
 
 STATIC void emit_native_end_finally(emit_t *emit) {
-    emit_pre_pop_discard(emit);
+    // logic:
+    //   exc = pop_stack
+    //   if exc == None: pass
+    //   else: raise exc
+    // the check if exc is None is done in the MP_F_NATIVE_RAISE stub
+    vtype_kind_t vtype;
+    emit_pre_pop_reg(emit, &vtype, REG_ARG_1);
+    emit_call(emit, MP_F_NATIVE_RAISE);
     emit_post(emit);
 }
 

py/nativeglue.c

@@ -80,8 +80,11 @@ mp_obj_t mp_native_call_function_n_kw(mp_obj_t fun_in, mp_uint_t n_args_kw, cons
 }
 
 // wrapper that makes raise obj and raises it
-NORETURN void mp_native_raise(mp_obj_t o) {
-    nlr_raise(mp_make_raise_obj(o));
+// END_FINALLY opcode requires that we don't raise if o==None
+void mp_native_raise(mp_obj_t o) {
+    if (o != mp_const_none) {
+        nlr_raise(mp_make_raise_obj(o));
+    }
 }
 
 // these must correspond to the respective enum in runtime0.h

py/runtime.h

@@ -119,7 +119,7 @@ NORETURN void mp_not_implemented(const char *msg);
 mp_uint_t mp_convert_obj_to_native(mp_obj_t obj, mp_uint_t type);
 mp_obj_t mp_convert_native_to_obj(mp_uint_t val, mp_uint_t type);
 mp_obj_t mp_native_call_function_n_kw(mp_obj_t fun_in, mp_uint_t n_args_kw, const mp_obj_t *args);
-NORETURN void mp_native_raise(mp_obj_t o);
+void mp_native_raise(mp_obj_t o);
 
 extern struct _mp_obj_list_t mp_sys_path_obj;
 extern struct _mp_obj_list_t mp_sys_argv_obj;

tests/run-tests

@@ -78,7 +78,7 @@ def run_tests(pyb, tests, args):
     # Some tests are known to fail with native emitter
     # Remove them from the below when they work
     if args.emit == 'native':
-        skip_tests.update({'basics/%s.py' % t for t in 'bytes_gen class_store_class class_super class_super_object closure1 closure2 closure_defargs del_deref del_local fun3 fun_calldblstar fun_callstar fun_callstardblstar fun_defargs fun_defargs2 fun_kwargs fun_kwonly fun_kwonlydef fun_kwvarargs fun_varargs gen_yield_from gen_yield_from_close gen_yield_from_ducktype gen_yield_from_exc gen_yield_from_iter gen_yield_from_send gen_yield_from_throw generator1 generator2 generator_args generator_close generator_closure generator_exc generator_return generator_send globals_del string_format string_join subclass_native2_list subclass_native2_tuple try2 try_finally1 try_finally_loops try_finally_return try_reraise try_reraise2 unboundlocal with1 with_break with_continue with_return'.split()})
+        skip_tests.update({'basics/%s.py' % t for t in 'bytes_gen class_store_class class_super class_super_object closure1 closure2 closure_defargs del_deref del_local fun3 fun_calldblstar fun_callstar fun_callstardblstar fun_defargs fun_defargs2 fun_kwargs fun_kwonly fun_kwonlydef fun_kwvarargs fun_varargs gen_yield_from gen_yield_from_close gen_yield_from_ducktype gen_yield_from_exc gen_yield_from_iter gen_yield_from_send gen_yield_from_throw generator1 generator2 generator_args generator_close generator_closure generator_exc generator_return generator_send globals_del string_format string_join subclass_native2_list subclass_native2_tuple try_finally_loops try_finally_return try_reraise try_reraise2 unboundlocal with1 with_break with_continue with_return'.split()})
         skip_tests.add('float/string_format.py')
         skip_tests.add('import/gen_context.py')
         skip_tests.add('io/file_with.py')