1 /*
  2  * Copyright (c) 2014, 2020, 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 "jfr/leakprofiler/chains/bitset.inline.hpp"
 27 #include "jfr/leakprofiler/chains/dfsClosure.hpp"
 28 #include "jfr/leakprofiler/chains/edge.hpp"
 29 #include "jfr/leakprofiler/chains/edgeStore.hpp"
 30 #include "jfr/leakprofiler/chains/rootSetClosure.hpp"
 31 #include "jfr/leakprofiler/utilities/granularTimer.hpp"
 32 #include "jfr/leakprofiler/utilities/rootType.hpp"
 33 #include "jfr/leakprofiler/utilities/unifiedOopRef.inline.hpp"
 34 #include "memory/iterator.inline.hpp"
 35 #include "memory/resourceArea.hpp"
 36 #include "oops/access.inline.hpp"
 37 #include "oops/oop.inline.hpp"
 38 #include "utilities/align.hpp"
 39 
 40 UnifiedOopRef DFSClosure::_reference_stack[max_dfs_depth];
 41 
 42 void DFSClosure::find_leaks_from_edge(EdgeStore* edge_store,
 43                                       BitSet* mark_bits,
 44                                       const Edge* start_edge) {
 45   assert(edge_store != NULL, "invariant");
 46   assert(mark_bits != NULL," invariant");
 47   assert(start_edge != NULL, "invariant");
 48 
 49   // Depth-first search, starting from a BFS egde
 50   DFSClosure dfs(edge_store, mark_bits, start_edge);
 51   start_edge->pointee()->oop_iterate(&dfs);
 52 }
 53 
 54 void DFSClosure::find_leaks_from_root_set(EdgeStore* edge_store,
 55                                           BitSet* mark_bits) {
 56   assert(edge_store != NULL, "invariant");
 57   assert(mark_bits != NULL, "invariant");
 58 
 59   // Mark root set, to avoid going sideways
 60   DFSClosure dfs(edge_store, mark_bits, NULL);
 61   dfs._max_depth = 1;
 62   RootSetClosure<DFSClosure> rs(&dfs);
 63   rs.process();
 64 
 65   // Depth-first search
 66   dfs._max_depth = max_dfs_depth;
 67   dfs._ignore_root_set = true;
 68   rs.process();
 69 }
 70 
 71 DFSClosure::DFSClosure(EdgeStore* edge_store, BitSet* mark_bits, const Edge* start_edge)
 72   :_edge_store(edge_store), _mark_bits(mark_bits), _start_edge(start_edge),
 73   _max_depth(max_dfs_depth), _depth(0), _ignore_root_set(false) {
 74 }
 75 
 76 void DFSClosure::closure_impl(UnifiedOopRef reference, const oop pointee) {
 77   assert(pointee != NULL, "invariant");
 78   assert(!reference.is_null(), "invariant");
 79 
 80   if (GranularTimer::is_finished()) {
 81     return;
 82   }
 83   if (_depth == 0 && _ignore_root_set) {
 84     // Root set is already marked, but we want
 85     // to continue, so skip is_marked check.
 86     assert(_mark_bits->is_marked(pointee), "invariant");
 87   }  else {
 88     if (_mark_bits->is_marked(pointee)) {
 89       return;
 90     }
 91   }
 92   _reference_stack[_depth] = reference;
 93   _mark_bits->mark_obj(pointee);
 94   assert(_mark_bits->is_marked(pointee), "invariant");
 95 
 96   // is the pointee a sample object?
 97   if (pointee->mark().is_marked()) {
 98     add_chain();
 99   }
100 
101   assert(_max_depth >= 1, "invariant");
102   if (_depth < _max_depth - 1) {
103     _depth++;
104     pointee->oop_iterate(this);
105     assert(_depth > 0, "invariant");
106     _depth--;
107   }
108 }
109 
110 void DFSClosure::add_chain() {
111   const size_t array_length = _depth + 2;
112 
113   ResourceMark rm;
114   Edge* const chain = NEW_RESOURCE_ARRAY(Edge, array_length);
115   size_t idx = 0;
116 
117   // aggregate from depth-first search
118   for (size_t i = 0; i <= _depth; i++) {
119     const size_t next = idx + 1;
120     const size_t depth = _depth - i;
121     chain[idx++] = Edge(&chain[next], _reference_stack[depth]);
122   }
123   assert(_depth + 1 == idx, "invariant");
124   assert(array_length == idx + 1, "invariant");
125 
126   // aggregate from breadth-first search
127   if (_start_edge != NULL) {
128     chain[idx++] = *_start_edge;
129   } else {
130     chain[idx - 1] = Edge(NULL, chain[idx - 1].reference());
131   }
132   _edge_store->put_chain(chain, idx + (_start_edge != NULL ? _start_edge->distance_to_root() : 0));
133 }
134 
135 void DFSClosure::do_oop(oop* ref) {
136   assert(ref != NULL, "invariant");
137   assert(is_aligned(ref, HeapWordSize), "invariant");
138   const oop pointee = HeapAccess<AS_NO_KEEPALIVE>::oop_load(ref);
139   if (pointee != NULL) {
140     closure_impl(UnifiedOopRef::encode_in_heap(ref), pointee);
141   }
142 }
143 
144 void DFSClosure::do_oop(narrowOop* ref) {
145   assert(ref != NULL, "invariant");
146   assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
147   const oop pointee = HeapAccess<AS_NO_KEEPALIVE>::oop_load(ref);
148   if (pointee != NULL) {
149     closure_impl(UnifiedOopRef::encode_in_heap(ref), pointee);
150   }
151 }
152 
153 void DFSClosure::do_root(UnifiedOopRef ref) {
154   assert(!ref.is_null(), "invariant");
155   const oop pointee = ref.dereference();
156   assert(pointee != NULL, "invariant");
157   closure_impl(ref, pointee);
158 }