Add %GetCallerJSFunction intrinsic

src/runtime/runtime-internal.cc

Index: src/runtime/runtime-internal.cc
diff --git a/src/runtime/runtime-internal.cc b/src/runtime/runtime-internal.cc
index e0e583e4021122d75999f9c1de54b5c08da14c00..afc7df77d171af248ba03d5baf5bc7bf84377e9c 100644
--- a/src/runtime/runtime-internal.cc
+++ b/src/runtime/runtime-internal.cc
@@ -416,5 +416,26 @@ RUNTIME_FUNCTION(Runtime_GetTypeFeedbackVector) {
   CONVERT_ARG_CHECKED(JSFunction, function, 0);
   return function->shared()->feedback_vector();
 }
+
+
+RUNTIME_FUNCTION(Runtime_GetCallerJSFunction) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 0);
+  JavaScriptFrameIterator it(isolate);
+  int frames_to_count = 2;
+  int function_index = 0;
+  List<JSFunction*> functions(FLAG_max_inlining_levels + 1);
+  while (frames_to_count-- != 0) {
+    if (function_index == 0) {
+      functions.Rewind(0);
+      it.frame()->GetFunctions(&functions);
+      it.Advance();
+      function_index = functions.length() - 1;
+    } else {
+      function_index--;
+    }
+  }
+  return functions[function_index];
+}
 }  // namespace internal
 }  // namespace v8