src/hotspot/cpu/riscv/gc/shenandoah/shenandoahBarrierSetAssembler_riscv.cpp

*** 907,11 ***
        __ ld(_obj, _addr);
      }
    }
  
    // If the object is null, there is no point in applying barriers.
!   maybe_far_jump_if_zero(masm, _obj);
  
    // We need to make sure that loads done by callers survive across slow-path calls.
    // For self-loads, we need to care about the case when both KA and LRB are enabled (rare).
    bool needs_both_barriers = _needs_keep_alive_barrier && _needs_load_ref_barrier;
    if (!_do_load || needs_both_barriers) {
--- 907,11 ---
        __ ld(_obj, _addr);
      }
    }
  
    // If the object is null, there is no point in applying barriers.
!   maybe_far_jump_if_zero(masm, _obj, continuation());
  
    // We need to make sure that loads done by callers survive across slow-path calls.
    // For self-loads, we need to care about the case when both KA and LRB are enabled (rare).
    bool needs_both_barriers = _needs_keep_alive_barrier && _needs_load_ref_barrier;
    if (!_do_load || needs_both_barriers) {

*** 930,27 ***
    } else {
      ShouldNotReachHere();
    }
  }
  
! void ShenandoahBarrierStubC2::maybe_far_jump_if_zero(MacroAssembler& masm, Register reg) {
    Label L_short_jump;
    __ bnez(reg, L_short_jump);
!   __ j(*continuation());
    __ bind(L_short_jump);
  }
  
  void ShenandoahBarrierStubC2::keepalive(MacroAssembler& masm, Label* L_done) {
    Address index(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
    Address buffer(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
    Label L_through, L_slowpath;
  
!   // If another barrier is enabled as well, do a runtime check for a specific barrier.
!   if (_needs_load_ref_barrier) {
!     assert(L_done == nullptr, "L_done is always null when _needs_load_ref_barrier is true");
!     Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::MARKING)));
!     __ lbu(_tmp1, gc_state_fast);
      __ beqz(_tmp1, L_through);
    }
  
    // Fast-path: put object into buffer.
    // If buffer is already full, go slow.
--- 930,28 ---
    } else {
      ShouldNotReachHere();
    }
  }
  
! void ShenandoahBarrierStubC2::maybe_far_jump_if_zero(MacroAssembler& masm, Register reg, Label* L_target) {
    Label L_short_jump;
    __ bnez(reg, L_short_jump);
!   __ j(*L_target);
    __ bind(L_short_jump);
  }
  
  void ShenandoahBarrierStubC2::keepalive(MacroAssembler& masm, Label* L_done) {
    Address index(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
    Address buffer(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
    Label L_through, L_slowpath;
  
!   // Hotpatched GC checks only care about idle/non-idle state, so we need to check again here.
!   Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::MARKING)));
!   __ lbu(_tmp1, gc_state_fast);
!   if (L_done != nullptr) {
!     maybe_far_jump_if_zero(masm, _tmp1, L_done);
+   } else {
      __ beqz(_tmp1, L_through);
    }
  
    // Fast-path: put object into buffer.
    // If buffer is already full, go slow.

*** 996,17 ***
  }
  
  void ShenandoahBarrierStubC2::lrb(MacroAssembler& masm) {
    Label L_slow;
  
!   // If another barrier is enabled as well, do a runtime check for a specific barrier.
!   if (_needs_keep_alive_barrier) {
!     char state_to_check = ShenandoahHeap::HAS_FORWARDED | (_needs_load_ref_weak_barrier ? ShenandoahHeap::WEAK_ROOTS : 0);
!     Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(state_to_check)));
!     __ lbu(_tmp1, gc_state_fast);
-     maybe_far_jump_if_zero(masm, _tmp1);
-   }
  
    // If weak references are being processed, weak/phantom loads need to go slow,
    // regardless of their cset status.
    if (_needs_load_ref_weak_barrier) {
      Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::WEAK_ROOTS)));
--- 997,15 ---
  }
  
  void ShenandoahBarrierStubC2::lrb(MacroAssembler& masm) {
    Label L_slow;
  
!   // Hotpatched GC checks only care about idle/non-idle state, so we need to check again here.
!   char state_to_check = ShenandoahHeap::HAS_FORWARDED | (_needs_load_ref_weak_barrier ? ShenandoahHeap::WEAK_ROOTS : 0);
!   Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(state_to_check)));
!   __ lbu(_tmp1, gc_state_fast);
!   maybe_far_jump_if_zero(masm, _tmp1, continuation());
  
    // If weak references are being processed, weak/phantom loads need to go slow,
    // regardless of their cset status.
    if (_needs_load_ref_weak_barrier) {
      Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::WEAK_ROOTS)));

*** 1023,11 ***
  
    __ mv(_tmp1, ShenandoahHeap::in_cset_fast_test_addr());
    __ srli(_tmp2, _tmp2, ShenandoahHeapRegion::region_size_bytes_shift_jint());
    __ add(_tmp1, _tmp1, _tmp2);
    __ lbu(_tmp1, Address(_tmp1, 0));
!   maybe_far_jump_if_zero(masm, _tmp1);
  
    // Slow path
    __ bind(L_slow);
  
    // Obj is the result, need to temporarily stop preserving it.
--- 1022,11 ---
  
    __ mv(_tmp1, ShenandoahHeap::in_cset_fast_test_addr());
    __ srli(_tmp2, _tmp2, ShenandoahHeapRegion::region_size_bytes_shift_jint());
    __ add(_tmp1, _tmp1, _tmp2);
    __ lbu(_tmp1, Address(_tmp1, 0));
!   maybe_far_jump_if_zero(masm, _tmp1, continuation());
  
    // Slow path
    __ bind(L_slow);
  
    // Obj is the result, need to temporarily stop preserving it.