src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp

*** 2143,42 ***
  
      // Load the oop from the handle
      __ movptr(obj_reg, Address(oop_handle_reg, 0));
  
      if (!UseHeavyMonitors) {
  
!       // Load immediate 1 into swap_reg %rax
!       __ movl(swap_reg, 1);
- 
-       // Load (object->mark() | 1) into swap_reg %rax
-       __ orptr(swap_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
  
!       // Save (object->mark() | 1) into BasicLock's displaced header
!       __ movptr(Address(lock_reg, mark_word_offset), swap_reg);
  
!       // src -> dest iff dest == rax else rax <- dest
!       __ lock();
!       __ cmpxchgptr(lock_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
!       __ jcc(Assembler::equal, count_mon);
  
!       // Hmm should this move to the slow path code area???
  
!       // Test if the oopMark is an obvious stack pointer, i.e.,
!       //  1) (mark & 3) == 0, and
!       //  2) rsp <= mark < mark + os::pagesize()
!       // These 3 tests can be done by evaluating the following
!       // expression: ((mark - rsp) & (3 - os::vm_page_size())),
!       // assuming both stack pointer and pagesize have their
!       // least significant 2 bits clear.
!       // NOTE: the oopMark is in swap_reg %rax as the result of cmpxchg
  
!       __ subptr(swap_reg, rsp);
!       __ andptr(swap_reg, 3 - (int)os::vm_page_size());
  
!       // Save the test result, for recursive case, the result is zero
!       __ movptr(Address(lock_reg, mark_word_offset), swap_reg);
!       __ jcc(Assembler::notEqual, slow_path_lock);
      } else {
        __ jmp(slow_path_lock);
      }
      __ bind(count_mon);
      __ inc_held_monitor_count();
--- 2143,47 ---
  
      // Load the oop from the handle
      __ movptr(obj_reg, Address(oop_handle_reg, 0));
  
      if (!UseHeavyMonitors) {
+       if (UseFastLocking) {
+         // Load object header
+         __ movptr(swap_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
+         __ fast_lock_impl(obj_reg, swap_reg, r15_thread, rscratch1, slow_path_lock);
+       } else {
+         // Load immediate 1 into swap_reg %rax
+         __ movl(swap_reg, 1);
  
!         // Load (object->mark() | 1) into swap_reg %rax
!         __ orptr(swap_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
  
!         // Save (object->mark() | 1) into BasicLock's displaced header
!         __ movptr(Address(lock_reg, mark_word_offset), swap_reg);
  
!         // src -> dest iff dest == rax else rax <- dest
!         __ lock();
!         __ cmpxchgptr(lock_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
!         __ jcc(Assembler::equal, count_mon);
  
!         // Hmm should this move to the slow path code area???
  
!         // Test if the oopMark is an obvious stack pointer, i.e.,
!         //  1) (mark & 3) == 0, and
!         //  2) rsp <= mark < mark + os::pagesize()
!         // These 3 tests can be done by evaluating the following
!         // expression: ((mark - rsp) & (3 - os::vm_page_size())),
!         // assuming both stack pointer and pagesize have their
!         // least significant 2 bits clear.
!         // NOTE: the oopMark is in swap_reg %rax as the result of cmpxchg
  
!         __ subptr(swap_reg, rsp);
!         __ andptr(swap_reg, 3 - (int)os::vm_page_size());
  
!         // Save the test result, for recursive case, the result is zero
!         __ movptr(Address(lock_reg, mark_word_offset), swap_reg);
!         __ jcc(Assembler::notEqual, slow_path_lock);
+       }
      } else {
        __ jmp(slow_path_lock);
      }
      __ bind(count_mon);
      __ inc_held_monitor_count();

*** 2288,11 ***
      Label fast_done;
  
      // Get locked oop from the handle we passed to jni
      __ movptr(obj_reg, Address(oop_handle_reg, 0));
  
!     if (!UseHeavyMonitors) {
        Label not_recur;
        // Simple recursive lock?
        __ cmpptr(Address(rsp, lock_slot_offset * VMRegImpl::stack_slot_size), NULL_WORD);
        __ jcc(Assembler::notEqual, not_recur);
        __ dec_held_monitor_count();
--- 2293,11 ---
      Label fast_done;
  
      // Get locked oop from the handle we passed to jni
      __ movptr(obj_reg, Address(oop_handle_reg, 0));
  
!     if (!UseHeavyMonitors && !UseFastLocking) {
        Label not_recur;
        // Simple recursive lock?
        __ cmpptr(Address(rsp, lock_slot_offset * VMRegImpl::stack_slot_size), NULL_WORD);
        __ jcc(Assembler::notEqual, not_recur);
        __ dec_held_monitor_count();

*** 2304,19 ***
      if (ret_type != T_FLOAT && ret_type != T_DOUBLE && ret_type != T_VOID) {
        save_native_result(masm, ret_type, stack_slots);
      }
  
      if (!UseHeavyMonitors) {
!       // get address of the stack lock
!       __ lea(rax, Address(rsp, lock_slot_offset * VMRegImpl::stack_slot_size));
!       //  get old displaced header
!       __ movptr(old_hdr, Address(rax, 0));
! 
!       // Atomic swap old header if oop still contains the stack lock
!       __ lock();
!       __ cmpxchgptr(old_hdr, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
!       __ jcc(Assembler::notEqual, slow_path_unlock);
        __ dec_held_monitor_count();
      } else {
        __ jmp(slow_path_unlock);
      }
  
--- 2309,25 ---
      if (ret_type != T_FLOAT && ret_type != T_DOUBLE && ret_type != T_VOID) {
        save_native_result(masm, ret_type, stack_slots);
      }
  
      if (!UseHeavyMonitors) {
!       if (UseFastLocking) {
!         __ movptr(swap_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
!         __ andptr(swap_reg, ~(int32_t)markWord::lock_mask_in_place);
!         __ fast_unlock_impl(obj_reg, swap_reg, lock_reg, slow_path_unlock);
!       } else {
!         // get address of the stack lock
!         __ lea(rax, Address(rsp, lock_slot_offset * VMRegImpl::stack_slot_size));
!         //  get old displaced header
!         __ movptr(old_hdr, Address(rax, 0));
+ 
+         // Atomic swap old header if oop still contains the stack lock
+         __ lock();
+         __ cmpxchgptr(old_hdr, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
+         __ jcc(Assembler::notEqual, slow_path_unlock);
+       }
        __ dec_held_monitor_count();
      } else {
        __ jmp(slow_path_unlock);
      }