1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "reference_table.h" 18 19 #include "base/mutex.h" 20 #include "indirect_reference_table.h" 21 #include "mirror/array.h" 22 #include "mirror/array-inl.h" 23 #include "mirror/class.h" 24 #include "mirror/class-inl.h" 25 #include "mirror/object-inl.h" 26 #include "mirror/string-inl.h" 27 #include "thread.h" 28 #include "utils.h" 29 30 namespace art { 31 32 ReferenceTable::ReferenceTable(const char* name, size_t initial_size, size_t max_size) 33 : name_(name), max_size_(max_size) { 34 CHECK_LE(initial_size, max_size); 35 entries_.reserve(initial_size); 36 } 37 38 ReferenceTable::~ReferenceTable() { 39 } 40 41 void ReferenceTable::Add(mirror::Object* obj) { 42 DCHECK(obj != NULL); 43 VerifyObject(obj); 44 if (entries_.size() >= max_size_) { 45 LOG(FATAL) << "ReferenceTable '" << name_ << "' " 46 << "overflowed (" << max_size_ << " entries)"; 47 } 48 entries_.push_back(GcRoot<mirror::Object>(obj)); 49 } 50 51 void ReferenceTable::Remove(mirror::Object* obj) { 52 // We iterate backwards on the assumption that references are LIFO. 53 for (int i = entries_.size() - 1; i >= 0; --i) { 54 mirror::Object* entry = entries_[i].Read(); 55 if (entry == obj) { 56 entries_.erase(entries_.begin() + i); 57 return; 58 } 59 } 60 } 61 62 // If "obj" is an array, return the number of elements in the array. 63 // Otherwise, return zero. 64 static size_t GetElementCount(mirror::Object* obj) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 65 if (obj == NULL || obj == kClearedJniWeakGlobal || !obj->IsArrayInstance()) { 66 return 0; 67 } 68 return obj->AsArray()->GetLength(); 69 } 70 71 struct ObjectComparator { 72 bool operator()(GcRoot<mirror::Object> root1, GcRoot<mirror::Object> root2) 73 // TODO: enable analysis when analysis can work with the STL. 74 NO_THREAD_SAFETY_ANALYSIS { 75 Locks::mutator_lock_->AssertSharedHeld(Thread::Current()); 76 mirror::Object* obj1 = root1.Read<kWithoutReadBarrier>(); 77 mirror::Object* obj2 = root2.Read<kWithoutReadBarrier>(); 78 // Ensure null references and cleared jweaks appear at the end. 79 if (obj1 == NULL) { 80 return true; 81 } else if (obj2 == NULL) { 82 return false; 83 } 84 if (obj1 == kClearedJniWeakGlobal) { 85 return true; 86 } else if (obj2 == kClearedJniWeakGlobal) { 87 return false; 88 } 89 90 // Sort by class... 91 if (obj1->GetClass() != obj2->GetClass()) { 92 return obj1->GetClass()->IdentityHashCode() < obj2->GetClass()->IdentityHashCode(); 93 } else { 94 // ...then by size... 95 size_t count1 = obj1->SizeOf(); 96 size_t count2 = obj2->SizeOf(); 97 if (count1 != count2) { 98 return count1 < count2; 99 } else { 100 // ...and finally by identity hash code. 101 return obj1->IdentityHashCode() < obj2->IdentityHashCode(); 102 } 103 } 104 } 105 }; 106 107 // Log an object with some additional info. 108 // 109 // Pass in the number of elements in the array (or 0 if this is not an 110 // array object), and the number of additional objects that are identical 111 // or equivalent to the original. 112 static void DumpSummaryLine(std::ostream& os, mirror::Object* obj, size_t element_count, 113 int identical, int equiv) 114 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 115 if (obj == NULL) { 116 os << " NULL reference (count=" << equiv << ")\n"; 117 return; 118 } 119 if (obj == kClearedJniWeakGlobal) { 120 os << " cleared jweak (count=" << equiv << ")\n"; 121 return; 122 } 123 124 std::string className(PrettyTypeOf(obj)); 125 if (obj->IsClass()) { 126 // We're summarizing multiple instances, so using the exemplar 127 // Class' type parameter here would be misleading. 128 className = "java.lang.Class"; 129 } 130 if (element_count != 0) { 131 StringAppendF(&className, " (%zd elements)", element_count); 132 } 133 134 size_t total = identical + equiv + 1; 135 std::string msg(StringPrintf("%5zd of %s", total, className.c_str())); 136 if (identical + equiv != 0) { 137 StringAppendF(&msg, " (%d unique instances)", equiv + 1); 138 } 139 os << " " << msg << "\n"; 140 } 141 142 size_t ReferenceTable::Size() const { 143 return entries_.size(); 144 } 145 146 void ReferenceTable::Dump(std::ostream& os) { 147 os << name_ << " reference table dump:\n"; 148 Dump(os, entries_); 149 } 150 151 void ReferenceTable::Dump(std::ostream& os, Table& entries) { 152 if (entries.empty()) { 153 os << " (empty)\n"; 154 return; 155 } 156 157 // Dump the most recent N entries. 158 const size_t kLast = 10; 159 size_t count = entries.size(); 160 int first = count - kLast; 161 if (first < 0) { 162 first = 0; 163 } 164 os << " Last " << (count - first) << " entries (of " << count << "):\n"; 165 for (int idx = count - 1; idx >= first; --idx) { 166 mirror::Object* ref = entries[idx].Read(); 167 if (ref == NULL) { 168 continue; 169 } 170 if (ref == kClearedJniWeakGlobal) { 171 os << StringPrintf(" %5d: cleared jweak\n", idx); 172 continue; 173 } 174 if (ref->GetClass() == NULL) { 175 // should only be possible right after a plain dvmMalloc(). 176 size_t size = ref->SizeOf(); 177 os << StringPrintf(" %5d: %p (raw) (%zd bytes)\n", idx, ref, size); 178 continue; 179 } 180 181 std::string className(PrettyTypeOf(ref)); 182 183 std::string extras; 184 size_t element_count = GetElementCount(ref); 185 if (element_count != 0) { 186 StringAppendF(&extras, " (%zd elements)", element_count); 187 } else if (ref->GetClass()->IsStringClass()) { 188 mirror::String* s = const_cast<mirror::Object*>(ref)->AsString(); 189 std::string utf8(s->ToModifiedUtf8()); 190 if (s->GetLength() <= 16) { 191 StringAppendF(&extras, " \"%s\"", utf8.c_str()); 192 } else { 193 StringAppendF(&extras, " \"%.16s... (%d chars)", utf8.c_str(), s->GetLength()); 194 } 195 } 196 os << StringPrintf(" %5d: ", idx) << ref << " " << className << extras << "\n"; 197 } 198 199 // Make a copy of the table and sort it. 200 Table sorted_entries; 201 for (size_t i = 0; i < entries.size(); ++i) { 202 mirror::Object* entry = entries[i].Read(); 203 sorted_entries.push_back(GcRoot<mirror::Object>(entry)); 204 } 205 std::sort(sorted_entries.begin(), sorted_entries.end(), ObjectComparator()); 206 207 // Remove any uninteresting stuff from the list. The sort moved them all to the end. 208 while (!sorted_entries.empty() && sorted_entries.back().IsNull()) { 209 sorted_entries.pop_back(); 210 } 211 while (!sorted_entries.empty() && 212 sorted_entries.back().Read<kWithoutReadBarrier>() == kClearedJniWeakGlobal) { 213 sorted_entries.pop_back(); 214 } 215 if (sorted_entries.empty()) { 216 return; 217 } 218 219 // Dump a summary of the whole table. 220 os << " Summary:\n"; 221 size_t equiv = 0; 222 size_t identical = 0; 223 for (size_t idx = 1; idx < count; idx++) { 224 mirror::Object* prev = sorted_entries[idx-1].Read<kWithoutReadBarrier>(); 225 mirror::Object* current = sorted_entries[idx].Read<kWithoutReadBarrier>(); 226 size_t element_count = GetElementCount(prev); 227 if (current == prev) { 228 // Same reference, added more than once. 229 identical++; 230 } else if (current->GetClass() == prev->GetClass() && GetElementCount(current) == element_count) { 231 // Same class / element count, different object. 232 equiv++; 233 } else { 234 // Different class. 235 DumpSummaryLine(os, prev, element_count, identical, equiv); 236 equiv = identical = 0; 237 } 238 } 239 // Handle the last entry. 240 DumpSummaryLine(os, sorted_entries.back().Read<kWithoutReadBarrier>(), 241 GetElementCount(sorted_entries.back().Read<kWithoutReadBarrier>()), 242 identical, equiv); 243 } 244 245 void ReferenceTable::VisitRoots(RootCallback* visitor, void* arg, const RootInfo& root_info) { 246 for (GcRoot<mirror::Object>& root : entries_) { 247 root.VisitRoot(visitor, arg, root_info); 248 } 249 } 250 251 } // namespace art 252
