rootSetClosure.cpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#include "precompiled.hpp"
#include "classfile/classLoaderData.hpp"
#include "classfile/systemDictionary.hpp"
#include "jfr/leakprofiler/chains/edgeQueue.hpp"
#include "jfr/leakprofiler/chains/rootSetClosure.hpp"
#include "jfr/leakprofiler/utilities/saveRestore.hpp"
#include "jfr/leakprofiler/utilities/unifiedOop.hpp"
#include "memory/universe.hpp"
#include "prims/jvmtiExport.hpp"
#include "runtime/jniHandles.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/thread.hpp"
#include "services/management.hpp"
#include "utilities/align.hpp"

RootSetClosure::RootSetClosure(EdgeQueue* edge_queue) :
  _edge_queue(edge_queue) {
}

void RootSetClosure::do_oop(oop* ref) {
  assert(ref != NULL, "invariant");
  // We discard unaligned root references because
  // our reference tagging scheme will use
  // the lowest bit in a represented reference
  // to indicate the reference is narrow.
  // It is mainly roots delivered via nmethods::do_oops()
  // that come in unaligned. It should be ok to duck these
  // since they are supposedly weak.
  if (!is_aligned(ref, HeapWordSize)) {
    return;
  }

  assert(is_aligned(ref, HeapWordSize), "invariant");
  const oop pointee = *ref;
  if (pointee != NULL) {
    closure_impl(ref, pointee);
  }
}

void RootSetClosure::do_oop(narrowOop* ref) {
  assert(ref != NULL, "invariant");
  assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
  const oop pointee = oopDesc::load_decode_heap_oop(ref);
  if (pointee != NULL) {
    closure_impl(UnifiedOop::encode(ref), pointee);
  }
}

void RootSetClosure::closure_impl(const oop* reference, const oop pointee) {
  if (!_edge_queue->is_full())  {
    _edge_queue->add(NULL, reference);
  }
}

void RootSetClosure::add_to_queue(EdgeQueue* edge_queue) {
  RootSetClosure rs(edge_queue);
  process_roots(&rs);
}

class RootSetClosureMarkScope : public MarkingCodeBlobClosure::MarkScope {
};

void RootSetClosure::process_roots(OopClosure* closure) {
  SaveRestoreCLDClaimBits save_restore_cld_claim_bits;
  RootSetClosureMarkScope mark_scope;

  CLDToOopClosure cldt_closure(closure);
  ClassLoaderDataGraph::always_strong_cld_do(&cldt_closure);
  CodeBlobToOopClosure blobs(closure, false);
  Threads::oops_do(closure, NULL, &blobs); // XXX set CLDClosure to NULL
  ObjectSynchronizer::oops_do(closure);
  Universe::oops_do(closure);
  JNIHandles::oops_do(closure);
  JvmtiExport::oops_do(closure);
  SystemDictionary::oops_do(closure);
  Management::oops_do(closure);
  StringTable::oops_do(closure);
}