[V8] Fixed infinite loop in Debug::PrepareStep

src/debug.cc

Index: src/debug.cc
diff --git a/src/debug.cc b/src/debug.cc
index 342aa505da7b6378f66f9636dfc3eef12ce3df1d..e96ef4626d7d402e927dd7f96634c8eaeaad4e3b 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -1360,11 +1360,16 @@ void Debug::PrepareStep(StepAction step_action,
         Isolate* isolate = JSFunction::cast(fun)->GetIsolate();
         Code* apply = isolate->builtins()->builtin(Builtins::kFunctionApply);
         Code* call = isolate->builtins()->builtin(Builtins::kFunctionCall);
+        // Find target function on the expression stack for expression like
+        // Function.call.call...apply(...)
+        int i = 1;
         while (fun->IsJSFunction()) {
           Code* code = JSFunction::cast(fun)->shared()->code();
           if (code != apply && code != call) break;
-          fun = frame->GetExpression(
-              expressions_count - 1 - call_function_arg_count);
+          DCHECK(expressions_count - i - call_function_arg_count >= 0);
+          fun = frame->GetExpression(expressions_count - i -
+                                     call_function_arg_count);
+          i -= 1;
         }
       }