Mark await expressions as caught or uncaught

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 0c354aab24fe6a425fc7f04731fadb90af5a606d..d70561a49a80ddd13f1381114b26b81e9ab75a93 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4597,6 +4597,9 @@ class HandlerTable : public FixedArray {
                  // catching are part of a desugaring and should therefore not
                  // be visible to the user (we won't notify the debugger of such
                  // exceptions).
+    ASYNC_AWAIT,  // The exception will be caught and cause a promise rejection
+                  // in the desugaring of an async function, so special
+                  // async/await handling in the debugger can take place.
   };
 
   // Getters for handler table based on ranges.
@@ -4649,8 +4652,8 @@ class HandlerTable : public FixedArray {
   static const int kReturnEntrySize = 2;
 
   // Encoding of the {handler} field.
-  class HandlerPredictionField : public BitField<CatchPrediction, 0, 2> {};
-  class HandlerOffsetField : public BitField<int, 2, 30> {};
+  class HandlerPredictionField : public BitField<CatchPrediction, 0, 3> {};
+  class HandlerOffsetField : public BitField<int, 3, 29> {};

[adamk, 2016/09/08 18:58:36]

Sorry I'm not familiar here, what is this an offset into? i.e., is 29 bits
sufficient?

[Dan Ehrenberg, 2016/09/08 22:34:05]

This is for a particular code object. I don't think it'll get anywhere near this
big. Anyway, if our tests hit it, it'll cause a DCHECK failure.

 };
 
 // ByteArray represents fixed sized byte arrays.  Used for the relocation info