1 /*
   2  * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "jfr/leakprofiler/chains/edgeQueue.hpp"
  29 #include "jfr/leakprofiler/chains/rootSetClosure.hpp"
  30 #include "jfr/leakprofiler/utilities/saveRestore.hpp"
  31 #include "jfr/leakprofiler/utilities/unifiedOop.hpp"
  32 #include "memory/universe.hpp"
  33 #include "prims/jvmtiExport.hpp"
  34 #include "runtime/jniHandles.hpp"
  35 #include "runtime/synchronizer.hpp"
  36 #include "runtime/thread.hpp"
  37 #include "services/management.hpp"
  38 #include "utilities/align.hpp"
  39 
  40 RootSetClosure::RootSetClosure(EdgeQueue* edge_queue) :
  41   _edge_queue(edge_queue) {
  42 }
  43 
  44 void RootSetClosure::do_oop(oop* ref) {
  45   assert(ref != NULL, "invariant");
  46   // We discard unaligned root references because
  47   // our reference tagging scheme will use
  48   // the lowest bit in a represented reference
  49   // to indicate the reference is narrow.
  50   // It is mainly roots delivered via nmethods::do_oops()
  51   // that come in unaligned. It should be ok to duck these
  52   // since they are supposedly weak.
  53   if (!is_aligned(ref, HeapWordSize)) {
  54     return;
  55   }
  56 
  57   assert(is_aligned(ref, HeapWordSize), "invariant");
  58   const oop pointee = *ref;
  59   if (pointee != NULL) {
  60     closure_impl(ref, pointee);
  61   }
  62 }
  63 
  64 void RootSetClosure::do_oop(narrowOop* ref) {
  65   assert(ref != NULL, "invariant");
  66   assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
  67   const oop pointee = oopDesc::load_decode_heap_oop(ref);
  68   if (pointee != NULL) {
  69     closure_impl(UnifiedOop::encode(ref), pointee);
  70   }
  71 }
  72 
  73 void RootSetClosure::closure_impl(const oop* reference, const oop pointee) {
  74   if (!_edge_queue->is_full())  {
  75     _edge_queue->add(NULL, reference);
  76   }
  77 }
  78 
  79 void RootSetClosure::add_to_queue(EdgeQueue* edge_queue) {
  80   RootSetClosure rs(edge_queue);
  81   process_roots(&rs);
  82 }
  83 
  84 class RootSetClosureMarkScope : public MarkingCodeBlobClosure::MarkScope {
  85 };
  86 
  87 void RootSetClosure::process_roots(OopClosure* closure) {
  88   SaveRestoreCLDClaimBits save_restore_cld_claim_bits;
  89   RootSetClosureMarkScope mark_scope;
  90 
  91   CLDToOopClosure cldt_closure(closure);
  92   ClassLoaderDataGraph::always_strong_cld_do(&cldt_closure);
  93   CodeBlobToOopClosure blobs(closure, false);
  94   Threads::oops_do(closure, NULL, &blobs); // XXX set CLDClosure to NULL
  95   ObjectSynchronizer::oops_do(closure);
  96   Universe::oops_do(closure);
  97   JNIHandles::oops_do(closure);
  98   JvmtiExport::oops_do(closure);
  99   SystemDictionary::oops_do(closure);
 100   Management::oops_do(closure);
 101   StringTable::oops_do(closure);
 102 }