Use InteropLibrary to get exception message

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/exception/ExceptionUtils.java

@@ -56,6 +56,7 @@
 import com.oracle.graal.python.nodes.call.CallNode;
 import com.oracle.graal.python.runtime.PythonContext;
 import com.oracle.truffle.api.CompilerAsserts;
+import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.RootCallTarget;
 import com.oracle.truffle.api.Truffle;
@@ -64,6 +65,8 @@
 import com.oracle.truffle.api.frame.Frame;
 import com.oracle.truffle.api.frame.FrameInstance;
 import com.oracle.truffle.api.frame.FrameInstanceVisitor;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
 import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.api.nodes.RootNode;
 import com.oracle.truffle.api.source.SourceSection;
@@ -106,7 +109,16 @@ public static void printPythonLikeStackTrace(Throwable e) {
             }
             printStack(stack);
         }
-        System.err.println(e.getMessage());
+        InteropLibrary lib = InteropLibrary.getUncached();
+        if (lib.isException(e)) {
+            try {
+                System.err.println(lib.getExceptionMessage(e));
+            } catch (UnsupportedMessageException unsupportedMessageException) {
+                throw CompilerDirectives.shouldNotReachHere();
+            }
+        } else {
+            System.err.println(e.getMessage());
+        }
     }
 
     private static void appendStackLine(ArrayList<String> stack, Node location, RootNode rootNode, boolean evenWithoutSource) {