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
ReferenceTable(const char * name,size_t initial_size,size_t max_size)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
~ReferenceTable()38 ReferenceTable::~ReferenceTable() {
39 }
40
Add(const mirror::Object * obj)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
Remove(const mirror::Object * obj)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.
GetElementCount(const mirror::Object * obj)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 {
operator ()art::ObjectComparator70 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.
DumpSummaryLine(std::ostream & os,const mirror::Object * obj,size_t element_count,int identical,int equiv)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
Size() const138 size_t ReferenceTable::Size() const {
139 return entries_.size();
140 }
141
Dump(std::ostream & os) const142 void ReferenceTable::Dump(std::ostream& os) const {
143 os << name_ << " reference table dump:\n";
144 Dump(os, entries_);
145 }
146
Dump(std::ostream & os,const Table & entries)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
VisitRoots(RootVisitor * visitor,void * arg)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