src/cpu/x86/vm/macroAssembler_x86.cpp

*** 2031,2041 ****
        lock();
      }
      cmpxchgptr(tmpReg, Address(objReg, 0));   // Uses RAX which is box
      bind(DONE_LABEL);
    } else {
!     Label DONE_LABEL, Stacked, CheckSucc;
  
      // Critically, the biased locking test must have precedence over
      // and appear before the (box->dhw == 0) recursive stack-lock test.
      if (UseBiasedLocking && !UseOptoBiasInlining) {
         biased_locking_exit(objReg, tmpReg, DONE_LABEL);
--- 2031,2041 ----
        lock();
      }
      cmpxchgptr(tmpReg, Address(objReg, 0));   // Uses RAX which is box
      bind(DONE_LABEL);
    } else {
!     Label DONE_LABEL, Stacked;
  
      // Critically, the biased locking test must have precedence over
      // and appear before the (box->dhw == 0) recursive stack-lock test.
      if (UseBiasedLocking && !UseOptoBiasInlining) {
         biased_locking_exit(objReg, tmpReg, DONE_LABEL);
*** 2225,2285 ****
      // Unfortunately none of our alignment mechanisms suffice.
      if ((EmitSync & 65536) == 0) {
         bind (CheckSucc);
      }
  #else // _LP64
      // It's inflated
      movptr(boxReg, Address (tmpReg, ObjectMonitor::owner_offset_in_bytes()-2));
      xorptr(boxReg, r15_thread);
      orptr (boxReg, Address (tmpReg, ObjectMonitor::recursions_offset_in_bytes()-2));
      jccb  (Assembler::notZero, DONE_LABEL);
      movptr(boxReg, Address (tmpReg, ObjectMonitor::cxq_offset_in_bytes()-2));
      orptr (boxReg, Address (tmpReg, ObjectMonitor::EntryList_offset_in_bytes()-2));
!     jccb  (Assembler::notZero, CheckSucc);
      movptr(Address (tmpReg, ObjectMonitor::owner_offset_in_bytes()-2), (int32_t)NULL_WORD);
      jmpb  (DONE_LABEL);
  
!     if ((EmitSync & 65536) == 0) {
!       Label LSuccess, LGoSlowPath ;
!       bind  (CheckSucc);
!       cmpptr(Address (tmpReg, ObjectMonitor::succ_offset_in_bytes()-2), (int32_t)NULL_WORD);
!       jccb  (Assembler::zero, LGoSlowPath);
! 
!       // I'd much rather use lock:andl m->_owner, 0 as it's faster than the
!       // the explicit ST;MEMBAR combination, but masm doesn't currently support
!       // "ANDQ M,IMM".  Don't use MFENCE here.  lock:add to TOS, xchg, etc
!       // are all faster when the write buffer is populated.
!       movptr (Address (tmpReg, ObjectMonitor::owner_offset_in_bytes()-2), (int32_t)NULL_WORD);
!       if (os::is_MP()) {
!          lock (); addl (Address(rsp, 0), 0);
!       }
!       cmpptr(Address (tmpReg, ObjectMonitor::succ_offset_in_bytes()-2), (int32_t)NULL_WORD);
!       jccb  (Assembler::notZero, LSuccess);
! 
!       movptr (boxReg, (int32_t)NULL_WORD);                   // box is really EAX
!       if (os::is_MP()) { lock(); }
!       cmpxchgptr(r15_thread, Address(tmpReg, ObjectMonitor::owner_offset_in_bytes()-2));
!       jccb  (Assembler::notEqual, LSuccess);
!       // Intentional fall-through into slow-path
! 
        bind  (LGoSlowPath);
        orl   (boxReg, 1);                      // set ICC.ZF=0 to indicate failure
        jmpb  (DONE_LABEL);
  
-       bind  (LSuccess);
-       testl (boxReg, 0);                      // set ICC.ZF=1 to indicate success
-       jmpb  (DONE_LABEL);
-     }
- 
      bind  (Stacked);
      movptr(tmpReg, Address (boxReg, 0));      // re-fetch
      if (os::is_MP()) { lock(); }
      cmpxchgptr(tmpReg, Address(objReg, 0)); // Uses RAX which is box
  
-     if (EmitSync & 65536) {
-        bind (CheckSucc);
-     }
  #endif
      bind(DONE_LABEL);
      // Avoid branch to branch on AMD processors
      if (EmitSync & 32768) {
         nop();
--- 2225,2260 ----
      // Unfortunately none of our alignment mechanisms suffice.
      if ((EmitSync & 65536) == 0) {
         bind (CheckSucc);
      }
  #else // _LP64
+     Label LGoSlowPath;
+ 
      // It's inflated
      movptr(boxReg, Address (tmpReg, ObjectMonitor::owner_offset_in_bytes()-2));
      xorptr(boxReg, r15_thread);
      orptr (boxReg, Address (tmpReg, ObjectMonitor::recursions_offset_in_bytes()-2));
      jccb  (Assembler::notZero, DONE_LABEL);
      movptr(boxReg, Address (tmpReg, ObjectMonitor::cxq_offset_in_bytes()-2));
      orptr (boxReg, Address (tmpReg, ObjectMonitor::EntryList_offset_in_bytes()-2));
!     orptr (boxReg, Address (tmpReg, ObjectMonitor::trace_exit_stack_offset_in_bytes()-2));
!     jccb  (Assembler::notZero, LGoSlowPath);
      movptr(Address (tmpReg, ObjectMonitor::owner_offset_in_bytes()-2), (int32_t)NULL_WORD);
      jmpb  (DONE_LABEL);
  
!     // We had a fast path here for when _succ was set, but event tracing
!     // requires always generating an event when there are any threads
!     // blocked on the monitor. Hence we enter the slow path.
      bind  (LGoSlowPath);
      orl   (boxReg, 1);                      // set ICC.ZF=0 to indicate failure
      jmpb  (DONE_LABEL);
  
      bind  (Stacked);
      movptr(tmpReg, Address (boxReg, 0));      // re-fetch
      if (os::is_MP()) { lock(); }
      cmpxchgptr(tmpReg, Address(objReg, 0)); // Uses RAX which is box
  
  #endif
      bind(DONE_LABEL);
      // Avoid branch to branch on AMD processors
      if (EmitSync & 32768) {
         nop();