1 /*
2 * Copyright (c) 1998, 2025, 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 "ci/ciEnv.hpp"
26 #include "ci/ciInstance.hpp"
27 #include "ci/ciMetadata.hpp"
28 #include "code/oopRecorder.inline.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "memory/allocation.inline.hpp"
31 #include "oops/oop.inline.hpp"
32 #include "runtime/jniHandles.inline.hpp"
33 #include "runtime/mutexLocker.hpp"
34 #include "runtime/os.hpp"
35 #include "utilities/copy.hpp"
36
37 #ifdef ASSERT
38 template <class T> int ValueRecorder<T>::_find_index_calls = 0;
39 template <class T> int ValueRecorder<T>::_hit_indexes = 0;
40 template <class T> int ValueRecorder<T>::_missed_indexes = 0;
41 #endif //ASSERT
42
43
44 template <class T> ValueRecorder<T>::ValueRecorder(Arena* arena) {
45 _handles = nullptr;
46 _indexes = nullptr;
47 _arena = arena;
48 _complete = false;
49 }
50
51 template <class T> template <class X> ValueRecorder<T>::IndexCache<X>::IndexCache() {
52 assert(first_index > 0, "initial zero state of cache must be invalid index");
53 Copy::zero_to_bytes(&_cache[0], sizeof(_cache));
54 }
55
56 template <class T> int ValueRecorder<T>::size() {
57 _complete = true;
58 if (_handles == nullptr) return 0;
59 return _handles->length() * sizeof(T);
60 }
61
62 template <class T> void ValueRecorder<T>::copy_values_to(nmethod* nm) {
63 assert(_complete, "must be frozen");
64 maybe_initialize(); // get non-null handles, even if we have no oops
65 nm->copy_values(_handles);
66 }
67
68 template <class T> void ValueRecorder<T>::maybe_initialize() {
69 if (_handles == nullptr) {
70 if (_arena != nullptr) {
71 _handles = new(_arena) GrowableArray<T>(_arena, 10, 0, T{});
72 _no_finds = new(_arena) GrowableArray<int>(_arena, 10, 0, 0);
73 } else {
74 _handles = new GrowableArray<T>(10, 0, T{});
75 _no_finds = new GrowableArray<int>(10, 0, 0);
76 }
77 }
78 }
79
80
81 template <class T> T ValueRecorder<T>::at(int index) {
82 // there is always a nullptr virtually present as first object
83 if (index == null_index) return nullptr;
84 return _handles->at(index - first_index);
85 }
86
87
88 template <class T> int ValueRecorder<T>::add_handle(T h, bool make_findable) {
89 assert(!_complete, "cannot allocate more elements after size query");
90 maybe_initialize();
91 // indexing uses 1 as an origin--0 means null
92 int index = _handles->length() + first_index;
93 _handles->append(h);
94
95 // Support correct operation of find_index().
96 assert(!(make_findable && !is_real(h)), "nulls are not findable");
97 if (make_findable) {
98 // This index may be returned from find_index().
99 if (_indexes != nullptr) {
100 int* cloc = _indexes->cache_location(h);
101 _indexes->set_cache_location_index(cloc, index);
102 } else if (index == index_cache_threshold && _arena != nullptr) {
103 _indexes = new(_arena) IndexCache<T>();
104 for (int i = 0; i < _handles->length(); i++) {
105 // Load the cache with pre-existing elements.
106 int index0 = i + first_index;
107 if (_no_finds->contains(index0)) continue;
108 int* cloc = _indexes->cache_location(_handles->at(i));
109 _indexes->set_cache_location_index(cloc, index0);
110 }
111 }
112 } else if (is_real(h)) {
113 // Remember that this index is not to be returned from find_index().
114 // This case is rare, because most or all uses of allocate_index pass
115 // an argument of nullptr or Universe::non_oop_word.
116 // Thus, the expected length of _no_finds is zero.
117 _no_finds->append(index);
118 }
119
120 return index;
121 }
122
123
124 template <class T> int ValueRecorder<T>::maybe_find_index(T h) {
125 debug_only(_find_index_calls++);
126 assert(!_complete, "cannot allocate more elements after size query");
127 maybe_initialize();
128 if (h == nullptr) return null_index;
129 assert(is_real(h), "must be valid");
130 int* cloc = (_indexes == nullptr)? nullptr: _indexes->cache_location(h);
131 if (cloc != nullptr) {
132 int cindex = _indexes->cache_location_index(cloc);
133 if (cindex == 0) {
134 return -1; // We know this handle is completely new.
135 }
136 if (cindex >= first_index && _handles->at(cindex - first_index) == h) {
137 debug_only(_hit_indexes++);
138 return cindex;
139 }
140 if (!_indexes->cache_location_collision(cloc)) {
141 return -1; // We know the current cache occupant is unique to that cloc.
142 }
143 }
144
145 // Not found in cache, due to a cache collision. (Or, no cache at all.)
146 // Do a linear search, most recent to oldest.
147 for (int i = _handles->length() - 1; i >= 0; i--) {
148 if (_handles->at(i) == h) {
149 int findex = i + first_index;
150 if (_no_finds->contains(findex)) continue; // oops; skip this one
151 if (cloc != nullptr) {
152 _indexes->set_cache_location_index(cloc, findex);
153 }
154 debug_only(_missed_indexes++);
155 return findex;
156 }
157 }
158 return -1;
159 }
160
161 // Explicitly instantiate these types
162 template class ValueRecorder<Metadata*>;
163 template class ValueRecorder<jobject>;
164
165 oop ObjectLookup::ObjectEntry::oop_value() const { return JNIHandles::resolve(_value); }
166
167 ObjectLookup::ObjectLookup(): _values(4), _gc_count(Universe::heap()->total_collections()) {}
168
169 void ObjectLookup::maybe_resort() {
170 // The values are kept sorted by address which may be invalidated
171 // after a GC, so resort if a GC has occurred since last time.
172 if (_gc_count != Universe::heap()->total_collections()) {
173 _gc_count = Universe::heap()->total_collections();
174 _values.sort(sort_by_address);
175 }
176 }
177
178 int ObjectLookup::sort_by_address(oop a, oop b) {
179 // oopDesc::compare returns the opposite of what this function returned
180 return -(oopDesc::compare(a, b));
181 }
182
183 int ObjectLookup::sort_by_address(ObjectEntry* a, ObjectEntry* b) {
184 return sort_by_address(a->oop_value(), b->oop_value());
185 }
186
187 int ObjectLookup::sort_oop_by_address(oop const& a, ObjectEntry const& b) {
188 return sort_by_address(a, b.oop_value());
189 }
190
191 int ObjectLookup::find_index(jobject handle, OopRecorder* oop_recorder) {
192 if (handle == nullptr) {
193 return 0;
194 }
195 oop object = JNIHandles::resolve(handle);
196 maybe_resort();
197 bool found;
198 int location = _values.find_sorted<oop, sort_oop_by_address>(object, found);
199 if (!found) {
200 jobject handle = JNIHandles::make_local(object);
201 ObjectEntry r(handle, oop_recorder->allocate_oop_index(handle));
202 _values.insert_before(location, r);
203 return r.index();
204 }
205 return _values.at(location).index();
206 }
207
208 OopRecorder::OopRecorder(Arena* arena, bool deduplicate): _oops(arena), _metadata(arena) {
209 if (deduplicate) {
210 _object_lookup = new ObjectLookup();
211 } else {
212 _object_lookup = nullptr;
213 }
214 }
215
216 // Explicitly instantiate
217 template class ValueRecorder<address>;
218
219 ExternalsRecorder* ExternalsRecorder::_recorder = nullptr;
220
221 ExternalsRecorder::ExternalsRecorder(): _arena(mtCode), _externals(&_arena) {}
222
223 #ifndef PRODUCT
224 static int total_access_count = 0;
225 static GrowableArray<int>* extern_hist = nullptr;
226 #endif
227
228 void ExternalsRecorder_init() {
229 ExternalsRecorder::initialize();
230 }
231
232 void ExternalsRecorder::initialize() {
233 // After Mutex and before CodeCache are initialized
234 assert(_recorder == nullptr, "should initialize only once");
235 _recorder = new ExternalsRecorder();
236 #ifndef PRODUCT
237 if (PrintNMethodStatistics) {
238 Arena* arena = &_recorder->_arena;
239 extern_hist = new(arena) GrowableArray<int>(arena, 512, 512, 0);
240 }
241 #endif
242 }
243
244 int ExternalsRecorder::find_index(address adr) {
245 assert(_recorder != nullptr, "sanity");
246 MutexLocker ml(ExternalsRecorder_lock, Mutex::_no_safepoint_check_flag);
247 int index = _recorder->_externals.find_index(adr);
248 #ifndef PRODUCT
249 if (PrintNMethodStatistics) {
250 total_access_count++;
251 int n = extern_hist->at_grow(index, 0);
252 extern_hist->at_put(index, (n + 1));
253 }
254 #endif
255 return index;
256 }
257
258 address ExternalsRecorder::at(int index) {
259 assert(_recorder != nullptr, "sanity");
260 // find_index() may resize array by reallocating it and freeing old,
261 // we need loock here to make sure we not accessing to old freed array.
262 MutexLocker ml(ExternalsRecorder_lock, Mutex::_no_safepoint_check_flag);
263 return _recorder->_externals.at(index);
264 }
265
266 int ExternalsRecorder::count() {
267 assert(_recorder != nullptr, "sanity");
268 MutexLocker ml(ExternalsRecorder_lock, Mutex::_no_safepoint_check_flag);
269 return _recorder->_externals.count();
270 }
271
272 #ifndef PRODUCT
273 extern "C" {
274 // Order from large to small values
275 static int count_cmp(const void *i, const void *j) {
276 int a = *(int*)i;
277 int b = *(int*)j;
278 return a < b ? 1 : a > b ? -1 : 0;
279 }
280 }
281
282 void ExternalsRecorder::print_statistics() {
283 int cnt = count();
284 tty->print_cr("External addresses table: %d entries, %d accesses", cnt, total_access_count);
285 { // Print most accessed entries in the table.
286 int* array = NEW_C_HEAP_ARRAY(int, (2 * cnt), mtCode);
287 for (int i = 0; i < cnt; i++) {
288 array[(2 * i) + 0] = extern_hist->at(i);
289 array[(2 * i) + 1] = i;
290 }
291 // Reverse sort to have "hottest" addresses first.
292 qsort(array, cnt, 2*sizeof(int), count_cmp);
293 // Print all entries with Verbose flag otherwise only top 5.
294 int limit = (Verbose || cnt <= 5) ? cnt : 5;
295 int j = 0;
296 for (int i = 0; i < limit; i++) {
297 int index = array[(2 * i) + 1];
298 int n = extern_hist->at(index);
299 if (n > 0) {
300 address addr = at(index);
301 tty->print("%d: %8d " INTPTR_FORMAT " :", j++, n, p2i(addr));
302 if (addr != nullptr) {
303 if (StubRoutines::contains(addr)) {
304 StubCodeDesc* desc = StubCodeDesc::desc_for(addr);
305 if (desc == nullptr) {
306 desc = StubCodeDesc::desc_for(addr + frame::pc_return_offset);
307 }
308 const char* stub_name = (desc != nullptr) ? desc->name() : "<unknown>";
309 tty->print(" stub: %s", stub_name);
310 } else {
311 ResourceMark rm;
312 const int buflen = 1024;
313 char* buf = NEW_RESOURCE_ARRAY(char, buflen);
314 int offset = 0;
315 if (os::dll_address_to_function_name(addr, buf, buflen, &offset)) {
316 tty->print(" extn: %s", buf);
317 if (offset != 0) {
318 tty->print("+%d", offset);
319 }
320 } else {
321 if (CodeCache::contains((void*)addr)) {
322 // Something in CodeCache
323 tty->print(" in CodeCache");
324 } else {
325 // It could be string
326 memcpy(buf, (char*)addr, 80);
327 buf[80] = '\0';
328 tty->print(" '%s'", buf);
329 }
330 }
331 }
332 }
333 tty->cr();
334 }
335 }
336 }
337 }
338 #endif