C++ BarrierSet类代码示例

static void gen_arraycopy_barrier_pre(oop* dest, size_t count, bool dest_uninitialized) {
    assert(count != 0, "count should be non-zero");
    assert(count <= (size_t)max_intx, "count too large");
    BarrierSet* bs = Universe::heap()->barrier_set();
    assert(bs->has_write_ref_array_pre_opt(), "Must have pre-barrier opt");
    bs->write_ref_array_pre(dest, (int)count, dest_uninitialized);
}

 // use_prev_marking == true  -> use "prev" marking information,
 // use_prev_marking == false -> use "next" marking information
 VerifyLiveClosure(G1CollectedHeap* g1h, bool use_prev_marking) :
   _g1h(g1h), _bs(NULL), _containing_obj(NULL),
   _failures(false), _n_failures(0), _use_prev_marking(use_prev_marking)
 {
   BarrierSet* bs = _g1h->barrier_set();
   if (bs->is_a(BarrierSet::CardTableModRef))
     _bs = (CardTableModRefBS*)bs;
 }

 // _vo == UsePrevMarking -> use "prev" marking information,
 // _vo == UseNextMarking -> use "next" marking information,
 // _vo == UseMarkWord    -> use mark word from object header.
 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
   _g1h(g1h), _bs(NULL), _containing_obj(NULL),
   _failures(false), _n_failures(0), _vo(vo)
 {
   BarrierSet* bs = _g1h->barrier_set();
   if (bs->is_a(BarrierSet::CardTableModRef))
     _bs = (CardTableModRefBS*)bs;
 }

char* i486_env::string_for_offset(intptr_t value) {
  stringStream st;
  BarrierSet* bs = Universe::heap()->barrier_set();
  BarrierSet::Name bsn = bs->kind();
    if (bs->kind() == BarrierSet::CardTableModRef &&
	(jbyte*) value == ((CardTableModRefBS*)(bs))->byte_map_base) {
    st.print("word_map_base");
  } else {
    st.print("%d", value);
  }
  return st.as_string();
}

void PSScavenge::initialize() {
  // Arguments must have been parsed

  if (AlwaysTenure) {
    _tenuring_threshold = 0;
  } else if (NeverTenure) {
    _tenuring_threshold = markOopDesc::max_age + 1;
  } else {
    // We want to smooth out our startup times for the AdaptiveSizePolicy
    _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold :
                                                    MaxTenuringThreshold;
  }

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  PSYoungGen* young_gen = heap->young_gen();
  PSOldGen* old_gen = heap->old_gen();
  PSPermGen* perm_gen = heap->perm_gen();

  // Set boundary between young_gen and old_gen
  assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(),
         "perm above old");
  assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(),
         "old above young");
  _young_generation_boundary = young_gen->eden_space()->bottom();

  // Initialize ref handling object for scavenging.
  MemRegion mr = young_gen->reserved();

  _ref_processor =
    new ReferenceProcessor(mr,                         // span
                           ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
                           (int) ParallelGCThreads,    // mt processing degree
                           true,                       // mt discovery
                           (int) ParallelGCThreads,    // mt discovery degree
                           true,                       // atomic_discovery
                           NULL,                       // header provides liveness info
                           false);                     // next field updates do not need write barrier

  // Cache the cardtable
  BarrierSet* bs = Universe::heap()->barrier_set();
  assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind");
  _card_table = (CardTableExtension*)bs;

  _counters = new CollectorCounters("PSScavenge", 0);
}

void sparc_env::print_address(address adr, outputStream* st) {
  if (StubRoutines::contains(adr)) {
    StubCodeDesc *desc = StubCodeDesc::desc_for(adr);
    if (desc == NULL)
      desc = StubCodeDesc::desc_for(adr + frame::pc_return_offset);
    if (desc == NULL)
      st->print("Unknown stub at " INTPTR_FORMAT, adr);
    else {
      st->print("Stub::%s", desc->name());
      if (desc->begin() != adr)
	st->print("%+d 0x%p",adr - desc->begin(), adr);
      else if (WizardMode) st->print(" " INTPTR_FORMAT, adr);
    }
  } else {
    BarrierSet* bs = Universe::heap()->barrier_set();
    if (bs->kind() == BarrierSet::CardTableModRef &&
	adr == (address)((CardTableModRefBS*)(bs))->byte_map_base) {
      st->print("word_map_base");
      if (WizardMode) st->print(" " INTPTR_FORMAT, (intptr_t)adr);
    } else {
      st->print(INTPTR_FORMAT, (intptr_t)adr); 
    }
  }
}

//.........这里部分代码省略.........
    mark_sweep_phase2();

    // Don't add any more derived pointers during phase3
    COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
    COMPILER2_PRESENT(DerivedPointerTable::set_active(false));

    mark_sweep_phase3();

    mark_sweep_phase4();

    restore_marks();

    deallocate_stacks();

    if (ZapUnusedHeapArea) {
      // Do a complete mangle (top to end) because the usage for
      // scratch does not maintain a top pointer.
      young_gen->to_space()->mangle_unused_area_complete();
    }

    eden_empty = young_gen->eden_space()->is_empty();
    if (!eden_empty) {
      eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
    }

    // Update heap occupancy information which is used as
    // input to soft ref clearing policy at the next gc.
    Universe::update_heap_info_at_gc();

    survivors_empty = young_gen->from_space()->is_empty() &&
                      young_gen->to_space()->is_empty();
    young_gen_empty = eden_empty && survivors_empty;

    BarrierSet* bs = heap->barrier_set();
    if (bs->is_a(BarrierSet::ModRef)) {
      ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
      MemRegion old_mr = heap->old_gen()->reserved();
      MemRegion perm_mr = heap->perm_gen()->reserved();
      assert(perm_mr.end() <= old_mr.start(), "Generations out of order");

      if (young_gen_empty) {
        modBS->clear(MemRegion(perm_mr.start(), old_mr.end()));
      } else {
        modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end()));
      }
    }

    BiasedLocking::restore_marks();
    Threads::gc_epilogue();
    CodeCache::gc_epilogue();

    COMPILER2_PRESENT(DerivedPointerTable::update_pointers());

    ref_processor()->enqueue_discovered_references(NULL);

    // Update time of last GC
    reset_millis_since_last_gc();

    // Let the size policy know we're done
    size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);

    if (UseAdaptiveSizePolicy) {

      if (PrintAdaptiveSizePolicy) {
        gclog_or_tty->print("AdaptiveSizeStart: ");
        gclog_or_tty->stamp();

//.........这里部分代码省略.........
      { __ set_info("load_klass_patching", dont_gc_arguments);
        oop_maps = generate_patching(sasm, CAST_FROM_FN_PTR(address, move_klass_patching));
      }
      break;

    case load_mirror_patching_id:
      { __ set_info("load_mirror_patching", dont_gc_arguments);
        oop_maps = generate_patching(sasm, CAST_FROM_FN_PTR(address, move_mirror_patching));
      }
      break;

    case dtrace_object_alloc_id:
      { // O0: object
        __ set_info("dtrace_object_alloc", dont_gc_arguments);
        // we can't gc here so skip the oopmap but make sure that all
        // the live registers get saved.
        save_live_registers(sasm);

        __ save_thread(L7_thread_cache);
        __ call(CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_object_alloc),
                relocInfo::runtime_call_type);
        __ delayed()->mov(I0, O0);
        __ restore_thread(L7_thread_cache);

        restore_live_registers(sasm);
        __ ret();
        __ delayed()->restore();
      }
      break;

#if INCLUDE_ALL_GCS
    case g1_pre_barrier_slow_id:
      { // G4: previous value of memory
        BarrierSet* bs = Universe::heap()->barrier_set();
        if (bs->kind() != BarrierSet::G1SATBCTLogging) {
          __ save_frame(0);
          __ set((int)id, O1);
          __ call_RT(noreg, noreg, CAST_FROM_FN_PTR(address, unimplemented_entry), I0);
          __ should_not_reach_here();
          break;
        }

        __ set_info("g1_pre_barrier_slow_id", dont_gc_arguments);

        Register pre_val = G4;
        Register tmp  = G1_scratch;
        Register tmp2 = G3_scratch;

        Label refill, restart;
        bool with_frame = false; // I don't know if we can do with-frame.
        int satb_q_index_byte_offset =
          in_bytes(JavaThread::satb_mark_queue_offset() +
                   PtrQueue::byte_offset_of_index());
        int satb_q_buf_byte_offset =
          in_bytes(JavaThread::satb_mark_queue_offset() +
                   PtrQueue::byte_offset_of_buf());

        __ bind(restart);
        // Load the index into the SATB buffer. PtrQueue::_index is a
        // size_t so ld_ptr is appropriate
        __ ld_ptr(G2_thread, satb_q_index_byte_offset, tmp);

        // index == 0?
        __ cmp_and_brx_short(tmp, G0, Assembler::equal, Assembler::pn, refill);

        __ ld_ptr(G2_thread, satb_q_buf_byte_offset, tmp2);

static void gen_arraycopy_barrier(oop* dest, size_t count) {
    assert(count != 0, "count should be non-zero");
    BarrierSet* bs = Universe::heap()->barrier_set();
    assert(bs->has_write_ref_array_opt(), "Barrier set must have ref array opt");
    bs->write_ref_array((HeapWord*)dest, count);
}

//.........这里部分代码省略.........
    mark_sweep_phase2();

    // Don't add any more derived pointers during phase3
    COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
    COMPILER2_PRESENT(DerivedPointerTable::set_active(false));

    mark_sweep_phase3();

    mark_sweep_phase4();

    restore_marks();

    deallocate_stacks();

    if (ZapUnusedHeapArea) {
      // Do a complete mangle (top to end) because the usage for
      // scratch does not maintain a top pointer.
      young_gen->to_space()->mangle_unused_area_complete();
    }

    eden_empty = young_gen->eden_space()->is_empty();
    if (!eden_empty) {
      eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
    }

    // Update heap occupancy information which is used as
    // input to soft ref clearing policy at the next gc.
    Universe::update_heap_info_at_gc();

    survivors_empty = young_gen->from_space()->is_empty() &&
                      young_gen->to_space()->is_empty();
    young_gen_empty = eden_empty && survivors_empty;

    BarrierSet* bs = heap->barrier_set();
    if (bs->is_a(BarrierSet::ModRef)) {
      ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
      MemRegion old_mr = heap->old_gen()->reserved();
      if (young_gen_empty) {
        modBS->clear(MemRegion(old_mr.start(), old_mr.end()));
      } else {
        modBS->invalidate(MemRegion(old_mr.start(), old_mr.end()));
      }
    }

    // Delete metaspaces for unloaded class loaders and clean up loader_data graph
    ClassLoaderDataGraph::purge();
    MetaspaceAux::verify_metrics();

    BiasedLocking::restore_marks();
    CodeCache::gc_epilogue();
    JvmtiExport::gc_epilogue();

    COMPILER2_PRESENT(DerivedPointerTable::update_pointers());

    ref_processor()->enqueue_discovered_references(NULL);

    // Update time of last GC
    reset_millis_since_last_gc();

    // Let the size policy know we're done
    size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);

    if (UseAdaptiveSizePolicy) {

      if (PrintAdaptiveSizePolicy) {
        gclog_or_tty->print("AdaptiveSizeStart: ");

// This method contains no policy. You should probably
// be calling invoke() instead.
void PSMarkSweep::invoke_no_policy(bool& notify_ref_lock, bool clear_all_softrefs) {
    assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
    assert(ref_processor() != NULL, "Sanity");

    if (GC_locker::is_active()) return;

    ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
    assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

    PSYoungGen* young_gen = heap->young_gen();
    PSOldGen* old_gen = heap->old_gen();
    PSPermGen* perm_gen = heap->perm_gen();

    // Increment the invocation count
    heap->increment_total_collections();

    // We need to track unique mark sweep invocations as well.
    _total_invocations++;

    if (PrintHeapAtGC) {
        gclog_or_tty->print_cr(" {Heap before GC invocations=%d:", heap->total_collections());
        Universe::print();
    }

    // Fill in TLABs
    heap->ensure_parseability();

    if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
        HandleMark hm;  // Discard invalid handles created during verification
        tty->print(" VerifyBeforeGC:");
        Universe::verify(true);
    }

    {
        HandleMark hm;
        TraceTime t1("Full GC", PrintGC, true, gclog_or_tty);
        TraceCollectorStats tcs(counters());
        if (TraceGen1Time) accumulated_time()->start();

        // Let the size policy know we're starting
        AdaptiveSizePolicy* size_policy = heap->size_policy();
        size_policy->major_collection_begin();

        // When collecting the permanent generation methodOops may be moving,
        // so we either have to flush all bcp data or convert it into bci.
        NOT_CORE(CodeCache::gc_prologue());
        Threads::gc_prologue();

        // Capture heap size before collection for printing.
        size_t prev_used = heap->used();

        // Capture perm gen size before collection for sizing.
        size_t perm_gen_prev_used = perm_gen->used_in_bytes();

        bool marked_for_unloading = false;

        allocate_stacks();

        NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
        COMPILER2_ONLY(DerivedPointerTable::clear());

        ref_processor()->enable_discovery();

        mark_sweep_phase1(marked_for_unloading, clear_all_softrefs);

        mark_sweep_phase2();

        // Don't add any more derived pointers during phase3
        COMPILER2_ONLY(assert(DerivedPointerTable::is_active(), "Sanity"));
        COMPILER2_ONLY(DerivedPointerTable::set_active(false));

        mark_sweep_phase3();

        mark_sweep_phase4();

        restore_marks();

        deallocate_stacks();

        // "free at last gc" is calculated from these.
        Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity());
        Universe::set_heap_used_at_last_gc(Universe::heap()->used());

        bool all_empty = young_gen->eden_space()->is_empty() &&
                         young_gen->from_space()->is_empty() &&
                         young_gen->to_space()->is_empty();

        BarrierSet* bs = heap->barrier_set();
        if (bs->is_a(BarrierSet::ModRef)) {
            ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
            MemRegion old_mr = heap->old_gen()->reserved();
            MemRegion perm_mr = heap->perm_gen()->reserved();
            assert(old_mr.end() <= perm_mr.start(), "Generations out of order");

            if (all_empty) {
                modBS->clear(MemRegion(old_mr.start(), perm_mr.end()));
            } else {
                modBS->invalidate(MemRegion(old_mr.start(), perm_mr.end()));
//.........这里部分代码省略.........