--- old/src/hotspot/share/runtime/javaCalls.cpp	2020-01-24 19:19:08.482453789 +0000
+++ new/src/hotspot/share/runtime/javaCalls.cpp	2020-01-24 19:19:07.695176096 +0000
@@ -521,8 +521,6 @@
    intptr_t* _value;
 
  public:
-  bool _is_return;
-
   SignatureChekker(Symbol* signature,
                    BasicType return_type,
                    bool is_static,
@@ -532,17 +530,19 @@
     _pos(0),
     _return_type(return_type),
     _value_state(value_state),
-    _value(value),
-    _is_return(false)
+    _value(value)
   {
     if (!is_static) {
       check_value(true); // Receiver must be an oop
     }
+    do_parameters_on(this);
+    check_return_type(return_type);
   }
 
-  void check_value(bool type) {
+ private:
+  void check_value(bool is_reference) {
     uint state = _value_state[_pos++];
-    if (type) {
+    if (is_reference) {
       guarantee(is_value_state_indirect_oop(state),
                 "signature does not match pushed arguments: %u at %d",
                 state, _pos - 1);
@@ -553,38 +553,20 @@
     }
   }
 
-  void check_doing_return(bool state) { _is_return = state; }
-
   void check_return_type(BasicType t) {
-    guarantee(_is_return && t == _return_type, "return type does not match");
+    guarantee(t == _return_type, "return type does not match");
   }
 
-  void check_int(BasicType t) {
-    if (_is_return) {
-      check_return_type(t);
-      return;
-    }
+  void check_single_word() {
     check_value(false);
   }
 
-  void check_double(BasicType t) { check_long(t); }
-
-  void check_long(BasicType t) {
-    if (_is_return) {
-      check_return_type(t);
-      return;
-    }
-
+  void check_double_word() {
     check_value(false);
     check_value(false);
   }
 
-  void check_obj(BasicType t) {
-    if (_is_return) {
-      check_return_type(t);
-      return;
-    }
-
+  void check_reference() {
     intptr_t v = _value[_pos];
     if (v != 0) {
       // v is a "handle" referring to an oop, cast to integral type.
@@ -601,17 +583,26 @@
     check_value(true);          // Verify value state.
   }
 
-  void do_bool()                       { check_int(T_BOOLEAN);       }
-  void do_char()                       { check_int(T_CHAR);          }
-  void do_float()                      { check_int(T_FLOAT);         }
-  void do_double()                     { check_double(T_DOUBLE);     }
-  void do_byte()                       { check_int(T_BYTE);          }
-  void do_short()                      { check_int(T_SHORT);         }
-  void do_int()                        { check_int(T_INT);           }
-  void do_long()                       { check_long(T_LONG);         }
-  void do_void()                       { check_return_type(T_VOID);  }
-  void do_object(int begin, int end)   { check_obj(T_OBJECT);        }
-  void do_array(int begin, int end)    { check_obj(T_OBJECT);        }
+  friend class SignatureIterator;  // so do_parameters_on can call do_type
+  void do_type(BasicType type) {
+    switch (type) {
+    case T_BYTE:
+    case T_BOOLEAN:
+    case T_CHAR:
+    case T_SHORT:
+    case T_INT:
+    case T_FLOAT:  // this one also
+      check_single_word(); break;
+    case T_LONG:
+    case T_DOUBLE:
+      check_double_word(); break;
+    case T_ARRAY:
+    case T_OBJECT:
+      check_reference(); break;
+    default:
+      ShouldNotReachHere();
+    }
+  }
 };
 
 
@@ -629,7 +620,4 @@
                       method->is_static(),
                       _value_state,
                       _value);
-  sc.iterate_parameters();
-  sc.check_doing_return(true);
-  sc.iterate_returntype();
 }