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

rev 56771 : 8233339: Shenandoah: Centralize load barrier decisions into ShenandoahBarrierSet

*** 443,467 ****
      load_reference_barrier_not_null(masm, dst, src);
      __ bind(done);
    }
  }
  
  void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
               Register dst, Address src, Register tmp1, Register tmp_thread) {
-   bool on_oop = is_reference_type(type);
-   bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
-   bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
-   bool not_in_heap = (decorators & IN_NATIVE) != 0;
-   bool on_reference = on_weak || on_phantom;
-   bool is_traversal_mode = ShenandoahHeap::heap()->is_traversal_mode();
-   bool keep_alive = ((decorators & AS_NO_KEEPALIVE) == 0) || is_traversal_mode;
- 
    Register result_dst = dst;
    bool use_tmp1_for_dst = false;
  
!   if (on_oop) {
!     // We want to preserve src
      if (dst == src.base() || dst == src.index()) {
        // Use tmp1 for dst if possible, as it is not used in BarrierAssembler::load_at()
        if (tmp1->is_valid() && tmp1 != src.base() && tmp1 != src.index()) {
          dst = tmp1;
          use_tmp1_for_dst = true;
--- 443,475 ----
      load_reference_barrier_not_null(masm, dst, src);
      __ bind(done);
    }
  }
  
+ //
+ // Arguments:
+ //
+ // Inputs:
+ //   src:        oop location, might be clobbered
+ //   tmp1:       scratch register, might not be valid.
+ //   tmp_thread: unused
+ //
+ // Output:
+ //   dst:        oop loaded from src location
+ //
+ // Kill:
+ //   tmp1 (if it is valid)
+ //
  void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
               Register dst, Address src, Register tmp1, Register tmp_thread) {
    Register result_dst = dst;
    bool use_tmp1_for_dst = false;
+   bool need_load_reference_barrier = ShenandoahBarrierSet::need_load_reference_barrier(decorators, type);
  
!   // Only preserve src address if we need load reference barrier
!   if (need_load_reference_barrier) {
!     // Use tmp1 or rdi as temporary output register to avoid clobbering src
      if (dst == src.base() || dst == src.index()) {
        // Use tmp1 for dst if possible, as it is not used in BarrierAssembler::load_at()
        if (tmp1->is_valid() && tmp1 != src.base() && tmp1 != src.index()) {
          dst = tmp1;
          use_tmp1_for_dst = true;
*** 473,500 ****
      assert_different_registers(dst, src.base(), src.index());
    }
  
    BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
  
!   if (on_oop) {
!     if (not_in_heap && !is_traversal_mode) {
        load_reference_barrier_native(masm, dst, src);
      } else {
        load_reference_barrier(masm, dst, src);
      }
  
      if (dst != result_dst) {
        __ movptr(result_dst, dst);
  
        if (!use_tmp1_for_dst) {
          __ pop(dst);
        }
  
        dst = result_dst;
      }
  
!     if (ShenandoahKeepAliveBarrier && on_reference && keep_alive) {
        const Register thread = NOT_LP64(tmp_thread) LP64_ONLY(r15_thread);
        assert_different_registers(dst, tmp1, tmp_thread);
        NOT_LP64(__ get_thread(thread));
        // Generate the SATB pre-barrier code to log the value of
        // the referent field in an SATB buffer.
--- 481,510 ----
      assert_different_registers(dst, src.base(), src.index());
    }
  
    BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
  
!   if (!need_load_reference_barrier) return;
! 
!   if (ShenandoahBarrierSet::use_native_load_reference_barrier(decorators, type)) {
      load_reference_barrier_native(masm, dst, src);
    } else {
      load_reference_barrier(masm, dst, src);
    }
  
+   // Move loaded oop to final destination
    if (dst != result_dst) {
      __ movptr(result_dst, dst);
  
      if (!use_tmp1_for_dst) {
        __ pop(dst);
      }
  
      dst = result_dst;
    }
  
!   if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
      const Register thread = NOT_LP64(tmp_thread) LP64_ONLY(r15_thread);
      assert_different_registers(dst, tmp1, tmp_thread);
      NOT_LP64(__ get_thread(thread));
      // Generate the SATB pre-barrier code to log the value of
      // the referent field in an SATB buffer.
*** 504,514 ****
                                     thread /* thread */,
                                     tmp1 /* tmp */,
                                     true /* tosca_live */,
                                     true /* expand_call */);
      }
-   }
  }
  
  void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                Address dst, Register val, Register tmp1, Register tmp2) {
  
--- 514,523 ----