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.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(const mirror::Object* obj) { 42 DCHECK(obj != NULL); 43 if (entries_.size() == max_size_) { 44 LOG(FATAL) << "ReferenceTable '" << name_ << "' " 45 << "overflowed (" << max_size_ << " entries)"; 46 } 47 entries_.push_back(obj); 48 } 49 50 void ReferenceTable::Remove(const mirror::Object* obj) { 51 // We iterate backwards on the assumption that references are LIFO. 52 for (int i = entries_.size() - 1; i >= 0; --i) { 53 if (entries_[i] == obj) { 54 entries_.erase(entries_.begin() + i); 55 return; 56 } 57 } 58 } 59 60 // If "obj" is an array, return the number of elements in the array. 61 // Otherwise, return zero. 62 static size_t GetElementCount(const mirror::Object* obj) { 63 if (obj == NULL || obj == kClearedJniWeakGlobal || !obj->IsArrayInstance()) { 64 return 0; 65 } 66 return obj->AsArray()->GetLength(); 67 } 68 69 struct ObjectComparator { 70 bool operator()(const mirror::Object* obj1, const mirror::Object* obj2) 71 // TODO: enable analysis when analysis can work with the STL. 72 NO_THREAD_SAFETY_ANALYSIS { 73 Locks::mutator_lock_->AssertSharedHeld(Thread::Current()); 74 // Ensure null references and cleared jweaks appear at the end. 75 if (obj1 == NULL) { 76 return true; 77 } else if (obj2 == NULL) { 78 return false; 79 } 80 if (obj1 == kClearedJniWeakGlobal) { 81 return true; 82 } else if (obj2 == kClearedJniWeakGlobal) { 83 return false; 84 } 85 86 // Sort by class... 87 if (obj1->GetClass() != obj2->GetClass()) { 88 return obj1->GetClass()->IdentityHashCode() < obj2->IdentityHashCode(); 89 } else { 90 // ...then by size... 91 size_t count1 = obj1->SizeOf(); 92 size_t count2 = obj2->SizeOf(); 93 if (count1 != count2) { 94 return count1 < count2; 95 } else { 96 // ...and finally by identity hash code. 97 return obj1->IdentityHashCode() < obj2->IdentityHashCode(); 98 } 99 } 100 } 101 }; 102 103 // Log an object with some additional info. 104 // 105 // Pass in the number of elements in the array (or 0 if this is not an 106 // array object), and the number of additional objects that are identical 107 // or equivalent to the original. 108 static void DumpSummaryLine(std::ostream& os, const mirror::Object* obj, size_t element_count, 109 int identical, int equiv) 110 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 111 if (obj == NULL) { 112 os << " NULL reference (count=" << equiv << ")\n"; 113 return; 114 } 115 if (obj == kClearedJniWeakGlobal) { 116 os << " cleared jweak (count=" << equiv << ")\n"; 117 return; 118 } 119 120 std::string className(PrettyTypeOf(obj)); 121 if (obj->IsClass()) { 122 // We're summarizing multiple instances, so using the exemplar 123 // Class' type parameter here would be misleading. 124 className = "java.lang.Class"; 125 } 126 if (element_count != 0) { 127 StringAppendF(&className, " (%zd elements)", element_count); 128 } 129 130 size_t total = identical + equiv + 1; 131 std::string msg(StringPrintf("%5zd of %s", total, className.c_str())); 132 if (identical + equiv != 0) { 133 StringAppendF(&msg, " (%d unique instances)", equiv + 1); 134 } 135 os << " " << msg << "\n"; 136 } 137 138 size_t ReferenceTable::Size() const { 139 return entries_.size(); 140 } 141 142 void ReferenceTable::Dump(std::ostream& os) const { 143 os << name_ << " reference table dump:\n"; 144 Dump(os, entries_); 145 } 146 147 void ReferenceTable::Dump(std::ostream& os, const Table& entries) { 148 if (entries.empty()) { 149 os << " (empty)\n"; 150 return; 151 } 152 153 // Dump the most recent N entries. 154 const size_t kLast = 10; 155 size_t count = entries.size(); 156 int first = count - kLast; 157 if (first < 0) { 158 first = 0; 159 } 160 os << " Last " << (count - first) << " entries (of " << count << "):\n"; 161 for (int idx = count - 1; idx >= first; --idx) { 162 const mirror::Object* ref = entries[idx]; 163 if (ref == NULL) { 164 continue; 165 } 166 if (ref == kClearedJniWeakGlobal) { 167 os << StringPrintf(" %5d: cleared jweak\n", idx); 168 continue; 169 } 170 if (ref->GetClass() == NULL) { 171 // should only be possible right after a plain dvmMalloc(). 172 size_t size = ref->SizeOf(); 173 os << StringPrintf(" %5d: %p (raw) (%zd bytes)\n", idx, ref, size); 174 continue; 175 } 176 177 std::string className(PrettyTypeOf(ref)); 178 179 std::string extras; 180 size_t element_count = GetElementCount(ref); 181 if (element_count != 0) { 182 StringAppendF(&extras, " (%zd elements)", element_count); 183 } else if (ref->GetClass()->IsStringClass()) { 184 mirror::String* s = const_cast<mirror::Object*>(ref)->AsString(); 185 std::string utf8(s->ToModifiedUtf8()); 186 if (s->GetLength() <= 16) { 187 StringAppendF(&extras, " \"%s\"", utf8.c_str()); 188 } else { 189 StringAppendF(&extras, " \"%.16s... (%d chars)", utf8.c_str(), s->GetLength()); 190 } 191 } 192 os << StringPrintf(" %5d: ", idx) << ref << " " << className << extras << "\n"; 193 } 194 195 // Make a copy of the table and sort it. 196 Table sorted_entries(entries.begin(), entries.end()); 197 std::sort(sorted_entries.begin(), sorted_entries.end(), ObjectComparator()); 198 199 // Remove any uninteresting stuff from the list. The sort moved them all to the end. 200 while (!sorted_entries.empty() && sorted_entries.back() == NULL) { 201 sorted_entries.pop_back(); 202 } 203 while (!sorted_entries.empty() && sorted_entries.back() == kClearedJniWeakGlobal) { 204 sorted_entries.pop_back(); 205 } 206 if (sorted_entries.empty()) { 207 return; 208 } 209 210 // Dump a summary of the whole table. 211 os << " Summary:\n"; 212 size_t equiv = 0; 213 size_t identical = 0; 214 for (size_t idx = 1; idx < count; idx++) { 215 const mirror::Object* prev = sorted_entries[idx-1]; 216 const mirror::Object* current = sorted_entries[idx]; 217 size_t element_count = GetElementCount(prev); 218 if (current == prev) { 219 // Same reference, added more than once. 220 identical++; 221 } else if (current->GetClass() == prev->GetClass() && GetElementCount(current) == element_count) { 222 // Same class / element count, different object. 223 equiv++; 224 } else { 225 // Different class. 226 DumpSummaryLine(os, prev, element_count, identical, equiv); 227 equiv = identical = 0; 228 } 229 } 230 // Handle the last entry. 231 DumpSummaryLine(os, sorted_entries.back(), GetElementCount(sorted_entries.back()), identical, equiv); 232 } 233 234 void ReferenceTable::VisitRoots(RootVisitor* visitor, void* arg) { 235 for (const auto& ref : entries_) { 236 visitor(ref, arg); 237 } 238 } 239 240 } // namespace art 241
