8291555: Implement alternative fast-locking scheme

src/hotspot/share/runtime/lockStack.cpp

@@ -58,10 +58,12 @@ uint32_t LockStack::end_offset() {
   return static_cast<uint32_t>(offset);
 }
 
+#ifdef ASSERT
 static bool is_stack_watermark_processing(JavaThread* thread) {
   StackWatermark* watermark = StackWatermarkSet::get(thread, StackWatermarkKind::gc);
   return watermark->processing_started() && !watermark->processing_completed();
 }
+#endif
 
 #ifndef PRODUCT
 void LockStack::verify(const char* msg) const {

src/hotspot/share/runtime/objectMonitor.hpp

@@ -158,7 +158,7 @@ class ObjectMonitor : public CHeapObj<mtObjectMonitor> {
   static const uintptr_t ANONYMOUS_OWNER = 1;
 
 private:
-  static constexpr void* anon_owner_ptr() { return reinterpret_cast<void*>(ANONYMOUS_OWNER); }
+  static void* anon_owner_ptr() { return reinterpret_cast<void*>(ANONYMOUS_OWNER); }
 
   void* volatile _owner;            // pointer to owning thread OR BasicLock
   volatile uint64_t _previous_owner_tid;  // thread id of the previous owner of the monitor