avm1: Implement Action::Throw

core/src/avm1.rs

@@ -499,9 +499,17 @@ impl<'gc> Avm1<'gc> {
             return Ok(());
         }
         while !self.stack_frames.is_empty() {
-            self.with_current_reader_mut(context, |this, r, context| {
+            if let Err(e) = self.with_current_reader_mut(context, |this, r, context| {
                 this.do_next_action(context, r)
-            })?;
+            }) {
+                if let Error::ThrownValue(error) = &e {
+                    let string = error
+                        .coerce_to_string(self, context)
+                        .unwrap_or_else(|_| Cow::Borrowed("undefined"));
+                    log::info!(target: "avm_trace", "{}", string);
+                }
+                return Err(e);
+            }
         }
 
         // Operand stack should be empty at this point.
@@ -688,10 +696,14 @@ impl<'gc> Avm1<'gc> {
                     num_actions_to_skip,
                 } => self.action_wait_for_frame_2(context, num_actions_to_skip, reader),
                 Action::With { actions } => self.action_with(context, actions),
+                Action::Throw => self.action_throw(context),
                 _ => self.unknown_op(context, action),
             };
             if let Err(e) = result {
-                log::error!("AVM1 error: {}", e);
+                match &e {
+                    Error::ThrownValue(_) => {}
+                    e => log::error!("AVM1 error: {}", e),
+                }
                 if e.is_halting() {
                     self.halt();
                 }
@@ -2849,6 +2861,18 @@ impl<'gc> Avm1<'gc> {
         Ok(())
     }
 
+    fn action_throw(&mut self, context: &mut UpdateContext<'_, 'gc, '_>) -> Result<(), Error<'gc>> {
+        let value = self.pop();
+        avm_debug!(
+            "Thrown exception: {}",
+            value
+                .coerce_to_string(self, context)
+                .unwrap_or_else(|_| Cow::Borrowed("undefined"))
+        );
+        self.retire_stack_frame(context, Value::Undefined);
+        Err(Error::ThrownValue(value))
+    }
+
     fn action_with(
         &mut self,
         context: &mut UpdateContext<'_, 'gc, '_>,

core/src/avm1/return_value.rs

@@ -93,10 +93,13 @@ impl<'gc> ReturnValue<'gc> {
 
         match self {
             Immediate(val) => Ok(val),
-            ResultOf(frame) => {
-                avm.run_current_frame(context, frame)?;
-                Ok(avm.pop())
-            }
+            ResultOf(frame) => match avm.run_current_frame(context, frame) {
+                Ok(_) => Ok(avm.pop()),
+                Err(e) => {
+                    avm.retire_stack_frame(context, Value::Undefined);
+                    Err(e)
+                }
+            },
         }
     }
 

core/tests/regression_tests.rs

@@ -173,6 +173,8 @@ swf_tests! {
     (define_function2_preload, "avm1/define_function2_preload", 1),
     (define_function2_preload_order, "avm1/define_function2_preload_order", 1),
     (mcl_as_broadcaster, "avm1/mcl_as_broadcaster", 1),
+    (uncaught_exception, "avm1/uncaught_exception", 1),
+    (uncaught_exception_bubbled, "avm1/uncaught_exception_bubbled", 1),
     (loadmovie, "avm1/loadmovie", 2),
     (loadmovienum, "avm1/loadmovienum", 2),
     (loadmovie_method, "avm1/loadmovie_method", 2),

core/tests/swfs/avm1/uncaught_exception/output.txt

@@ -0,0 +1 @@
+Oh no!

core/tests/swfs/avm1/uncaught_exception_bubbled/output.txt

@@ -0,0 +1 @@
+Oh no!