src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp

rev 53513 : 8217016: Shenandoah: Streamline generation of CAS barriers

*** 590,657 ****
  // Special Shenandoah CAS implementation that handles false negatives
  // due to concurrent evacuation.
  #ifndef _LP64
  void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm,
                                                  Register res, Address addr, Register oldval, Register newval,
!                                                 bool exchange, bool encode, Register tmp1, Register tmp2) {
    // Shenandoah has no 32-bit version for this.
    Unimplemented();
  }
  #else
  void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm,
                                                  Register res, Address addr, Register oldval, Register newval,
!                                                 bool exchange, bool encode, Register tmp1, Register tmp2) {
!   if (!ShenandoahCASBarrier) {
! #ifdef _LP64
!     if (UseCompressedOops) {
!       if (encode) {
!         __ encode_heap_oop(oldval);
!         __ mov(rscratch1, newval);
!         __ encode_heap_oop(rscratch1);
!         newval = rscratch1;
!       }
!       if (os::is_MP()) {
!         __ lock();
!       }
!       // oldval (rax) is implicitly used by this instruction
!       __ cmpxchgl(newval, addr);
!     } else
! #endif
!       {
!         if (os::is_MP()) {
!           __ lock();
!         }
!         __ cmpxchgptr(newval, addr);
!       }
! 
!     if (!exchange) {
!       assert(res != NULL, "need result register");
!       __ setb(Assembler::equal, res);
!       __ movzbl(res, res);
!     }
!     return;
!   }
! 
    assert(ShenandoahCASBarrier, "Should only be used when CAS barrier is enabled");
    assert(oldval == rax, "must be in rax for implicit use in cmpxchg");
  
    Label retry, done;
  
-   // Apply storeval barrier to newval.
-   if (encode) {
-     storeval_barrier(masm, newval, tmp1);
-   }
- 
-   if (UseCompressedOops) {
-     if (encode) {
-       __ encode_heap_oop(oldval);
-       __ mov(rscratch1, newval);
-       __ encode_heap_oop(rscratch1);
-       newval = rscratch1;
-     }
-   }
- 
    // Remember oldval for retry logic below
    if (UseCompressedOops) {
      __ movl(tmp1, oldval);
    } else {
      __ movptr(tmp1, oldval);
--- 590,612 ----
  // Special Shenandoah CAS implementation that handles false negatives
  // due to concurrent evacuation.
  #ifndef _LP64
  void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm,
                                                  Register res, Address addr, Register oldval, Register newval,
!                                                 bool exchange, Register tmp1, Register tmp2) {
    // Shenandoah has no 32-bit version for this.
    Unimplemented();
  }
  #else
  void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm,
                                                  Register res, Address addr, Register oldval, Register newval,
!                                                 bool exchange, Register tmp1, Register tmp2) {
    assert(ShenandoahCASBarrier, "Should only be used when CAS barrier is enabled");
    assert(oldval == rax, "must be in rax for implicit use in cmpxchg");
  
    Label retry, done;
  
    // Remember oldval for retry logic below
    if (UseCompressedOops) {
      __ movl(tmp1, oldval);
    } else {
      __ movptr(tmp1, oldval);