1 /*
2 * Copyright (c) 1997, 2014, 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 "interpreter/oopMapCache.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "prims/jvmtiRedefineClassesTrace.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "runtime/signature.hpp"
33
34 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
35
36 class OopMapCacheEntry: private InterpreterOopMap {
37 friend class InterpreterOopMap;
38 friend class OopMapForCacheEntry;
39 friend class OopMapCache;
40 friend class VerifyClosure;
41
42 protected:
43 // Initialization
44 void fill(methodHandle method, int bci);
45 // fills the bit mask for native calls
46 void fill_for_native(methodHandle method);
47 void set_mask(CellTypeState* vars, CellTypeState* stack, int stack_top);
48
49 // Deallocate bit masks and initialize fields
50 void flush();
51
52 private:
53 void allocate_bit_mask(); // allocates the bit mask on C heap f necessary
54 void deallocate_bit_mask(); // allocates the bit mask on C heap f necessary
55 bool verify_mask(CellTypeState *vars, CellTypeState *stack, int max_locals, int stack_top);
56
57 public:
58 OopMapCacheEntry() : InterpreterOopMap() {
59 #ifdef ASSERT
60 _resource_allocate_bit_mask = false;
61 #endif
62 }
63 };
64
65
66 // Implementation of OopMapForCacheEntry
67 // (subclass of GenerateOopMap, initializes an OopMapCacheEntry for a given method and bci)
68
69 class OopMapForCacheEntry: public GenerateOopMap {
70 OopMapCacheEntry *_entry;
71 int _bci;
72 int _stack_top;
73
74 virtual bool report_results() const { return false; }
75 virtual bool possible_gc_point (BytecodeStream *bcs);
76 virtual void fill_stackmap_prolog (int nof_gc_points);
77 virtual void fill_stackmap_epilog ();
78 virtual void fill_stackmap_for_opcodes (BytecodeStream *bcs,
79 CellTypeState* vars,
80 CellTypeState* stack,
81 int stack_top);
82 virtual void fill_init_vars (GrowableArray<intptr_t> *init_vars);
83
84 public:
85 OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry *entry);
86
87 // Computes stack map for (method,bci) and initialize entry
88 void compute_map(TRAPS);
89 int size();
90 };
91
92
93 OopMapForCacheEntry::OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry* entry) : GenerateOopMap(method) {
94 _bci = bci;
95 _entry = entry;
96 _stack_top = -1;
97 }
98
99
100 void OopMapForCacheEntry::compute_map(TRAPS) {
101 assert(!method()->is_native(), "cannot compute oop map for native methods");
102 // First check if it is a method where the stackmap is always empty
103 if (method()->code_size() == 0 || method()->max_locals() + method()->max_stack() == 0) {
104 _entry->set_mask_size(0);
105 } else {
106 ResourceMark rm;
107 GenerateOopMap::compute_map(CATCH);
108 result_for_basicblock(_bci);
109 }
110 }
111
112
113 bool OopMapForCacheEntry::possible_gc_point(BytecodeStream *bcs) {
114 return false; // We are not reporting any result. We call result_for_basicblock directly
115 }
116
117
118 void OopMapForCacheEntry::fill_stackmap_prolog(int nof_gc_points) {
119 // Do nothing
120 }
121
122
123 void OopMapForCacheEntry::fill_stackmap_epilog() {
124 // Do nothing
125 }
126
127
128 void OopMapForCacheEntry::fill_init_vars(GrowableArray<intptr_t> *init_vars) {
129 // Do nothing
130 }
131
132
133 void OopMapForCacheEntry::fill_stackmap_for_opcodes(BytecodeStream *bcs,
134 CellTypeState* vars,
135 CellTypeState* stack,
136 int stack_top) {
137 // Only interested in one specific bci
138 if (bcs->bci() == _bci) {
139 _entry->set_mask(vars, stack, stack_top);
140 _stack_top = stack_top;
141 }
142 }
143
144
145 int OopMapForCacheEntry::size() {
146 assert(_stack_top != -1, "compute_map must be called first");
147 return ((method()->is_static()) ? 0 : 1) + method()->max_locals() + _stack_top;
148 }
149
150
151 // Implementation of InterpreterOopMap and OopMapCacheEntry
152
153 class VerifyClosure : public OffsetClosure {
154 private:
155 OopMapCacheEntry* _entry;
156 bool _failed;
157
158 public:
159 VerifyClosure(OopMapCacheEntry* entry) { _entry = entry; _failed = false; }
160 void offset_do(int offset) { if (!_entry->is_oop(offset)) _failed = true; }
161 bool failed() const { return _failed; }
162 };
163
164 InterpreterOopMap::InterpreterOopMap() {
165 initialize();
166 #ifdef ASSERT
167 _resource_allocate_bit_mask = true;
168 #endif
169 }
170
171 InterpreterOopMap::~InterpreterOopMap() {
172 // The expection is that the bit mask was allocated
173 // last in this resource area. That would make the free of the
174 // bit_mask effective (see how FREE_RESOURCE_ARRAY does a free).
175 // If it was not allocated last, there is not a correctness problem
176 // but the space for the bit_mask is not freed.
177 assert(_resource_allocate_bit_mask, "Trying to free C heap space");
178 if (mask_size() > small_mask_limit) {
179 FREE_RESOURCE_ARRAY(uintptr_t, _bit_mask[0], mask_word_size());
180 }
181 }
182
183 bool InterpreterOopMap::is_empty() const {
184 bool result = _method == NULL;
185 assert(_method != NULL || (_bci == 0 &&
186 (_mask_size == 0 || _mask_size == USHRT_MAX) &&
187 _bit_mask[0] == 0), "Should be completely empty");
188 return result;
189 }
190
191 void InterpreterOopMap::initialize() {
192 _method = NULL;
193 _mask_size = USHRT_MAX; // This value should cause a failure quickly
194 _bci = 0;
195 _expression_stack_size = 0;
196 for (int i = 0; i < N; i++) _bit_mask[i] = 0;
197 }
198
199 void InterpreterOopMap::iterate_oop(OffsetClosure* oop_closure) const {
200 int n = number_of_entries();
201 int word_index = 0;
202 uintptr_t value = 0;
203 uintptr_t mask = 0;
204 // iterate over entries
205 for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
206 // get current word
207 if (mask == 0) {
208 value = bit_mask()[word_index++];
209 mask = 1;
210 }
211 // test for oop
212 if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i);
213 }
214 }
215
216 void InterpreterOopMap::print() const {
217 int n = number_of_entries();
218 tty->print("oop map for ");
219 method()->print_value();
220 tty->print(" @ %d = [%d] { ", bci(), n);
221 for (int i = 0; i < n; i++) {
222 if (is_dead(i)) tty->print("%d+ ", i);
223 else
224 if (is_oop(i)) tty->print("%d ", i);
225 }
226 tty->print_cr("}");
227 }
228
229 class MaskFillerForNative: public NativeSignatureIterator {
230 private:
231 uintptr_t * _mask; // the bit mask to be filled
232 int _size; // the mask size in bits
233
234 void set_one(int i) {
235 i *= InterpreterOopMap::bits_per_entry;
236 assert(0 <= i && i < _size, "offset out of bounds");
237 _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));
238 }
239
240 public:
241 void pass_int() { /* ignore */ }
242 void pass_long() { /* ignore */ }
243 void pass_float() { /* ignore */ }
244 void pass_double() { /* ignore */ }
245 void pass_object() { set_one(offset()); }
246
247 MaskFillerForNative(methodHandle method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {
248 _mask = mask;
249 _size = size;
250 // initialize with 0
251 int i = (size + BitsPerWord - 1) / BitsPerWord;
252 while (i-- > 0) _mask[i] = 0;
253 }
254
255 void generate() {
256 NativeSignatureIterator::iterate();
257 }
258 };
259
260 bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {
261 // Check mask includes map
262 VerifyClosure blk(this);
263 iterate_oop(&blk);
264 if (blk.failed()) return false;
265
266 // Check if map is generated correctly
267 // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)
268 if (TraceOopMapGeneration && Verbose) tty->print("Locals (%d): ", max_locals);
269
270 for(int i = 0; i < max_locals; i++) {
271 bool v1 = is_oop(i) ? true : false;
272 bool v2 = vars[i].is_reference() ? true : false;
273 assert(v1 == v2, "locals oop mask generation error");
274 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
275 }
276
277 if (TraceOopMapGeneration && Verbose) { tty->cr(); tty->print("Stack (%d): ", stack_top); }
278 for(int j = 0; j < stack_top; j++) {
279 bool v1 = is_oop(max_locals + j) ? true : false;
280 bool v2 = stack[j].is_reference() ? true : false;
281 assert(v1 == v2, "stack oop mask generation error");
282 if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
283 }
284 if (TraceOopMapGeneration && Verbose) tty->cr();
285 return true;
286 }
287
288 void OopMapCacheEntry::allocate_bit_mask() {
289 if (mask_size() > small_mask_limit) {
290 assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");
291 _bit_mask[0] = (intptr_t)
292 NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size(), mtClass);
293 }
294 }
295
296 void OopMapCacheEntry::deallocate_bit_mask() {
297 if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {
298 assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
299 "This bit mask should not be in the resource area");
300 FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0]);
301 debug_only(_bit_mask[0] = 0;)
302 }
303 }
304
305
306 void OopMapCacheEntry::fill_for_native(methodHandle mh) {
307 assert(mh->is_native(), "method must be native method");
308 set_mask_size(mh->size_of_parameters() * bits_per_entry);
309 allocate_bit_mask();
310 // fill mask for parameters
311 MaskFillerForNative mf(mh, bit_mask(), mask_size());
312 mf.generate();
313 }
314
315
316 void OopMapCacheEntry::fill(methodHandle method, int bci) {
317 HandleMark hm;
318 // Flush entry to deallocate an existing entry
319 flush();
320 set_method(method());
321 set_bci(bci);
322 if (method->is_native()) {
323 // Native method activations have oops only among the parameters and one
324 // extra oop following the parameters (the mirror for static native methods).
325 fill_for_native(method);
326 } else {
327 EXCEPTION_MARK;
328 OopMapForCacheEntry gen(method, bci, this);
329 gen.compute_map(CATCH);
330 }
331 }
332
333
334 void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {
335 // compute bit mask size
336 int max_locals = method()->max_locals();
337 int n_entries = max_locals + stack_top;
338 set_mask_size(n_entries * bits_per_entry);
339 allocate_bit_mask();
340 set_expression_stack_size(stack_top);
341
342 // compute bits
343 int word_index = 0;
344 uintptr_t value = 0;
345 uintptr_t mask = 1;
346
347 CellTypeState* cell = vars;
348 for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {
349 // store last word
350 if (mask == 0) {
351 bit_mask()[word_index++] = value;
352 value = 0;
353 mask = 1;
354 }
355
356 // switch to stack when done with locals
357 if (entry_index == max_locals) {
358 cell = stack;
359 }
360
361 // set oop bit
362 if ( cell->is_reference()) {
363 value |= (mask << oop_bit_number );
364 }
365
366 // set dead bit
367 if (!cell->is_live()) {
368 value |= (mask << dead_bit_number);
369 assert(!cell->is_reference(), "dead value marked as oop");
370 }
371 }
372
373 // make sure last word is stored
374 bit_mask()[word_index] = value;
375
376 // verify bit mask
377 assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");
378
379
380 }
381
382 void OopMapCacheEntry::flush() {
383 deallocate_bit_mask();
384 initialize();
385 }
386
387
388 // Implementation of OopMapCache
389
390 #ifndef PRODUCT
391
392 static long _total_memory_usage = 0;
393
394 long OopMapCache::memory_usage() {
395 return _total_memory_usage;
396 }
397
398 #endif
399
400 void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {
401 assert(_resource_allocate_bit_mask,
402 "Should not resource allocate the _bit_mask");
403
404 set_method(from->method());
405 set_bci(from->bci());
406 set_mask_size(from->mask_size());
407 set_expression_stack_size(from->expression_stack_size());
408
409 // Is the bit mask contained in the entry?
410 if (from->mask_size() <= small_mask_limit) {
411 memcpy((void *)_bit_mask, (void *)from->_bit_mask,
412 mask_word_size() * BytesPerWord);
413 } else {
414 // The expectation is that this InterpreterOopMap is a recently created
415 // and empty. It is used to get a copy of a cached entry.
416 // If the bit mask has a value, it should be in the
417 // resource area.
418 assert(_bit_mask[0] == 0 ||
419 Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
420 "The bit mask should have been allocated from a resource area");
421 // Allocate the bit_mask from a Resource area for performance. Allocating
422 // from the C heap as is done for OopMapCache has a significant
423 // performance impact.
424 _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());
425 assert(_bit_mask[0] != 0, "bit mask was not allocated");
426 memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],
427 mask_word_size() * BytesPerWord);
428 }
429 }
430
431 inline unsigned int OopMapCache::hash_value_for(methodHandle method, int bci) const {
432 // We use method->code_size() rather than method->identity_hash() below since
433 // the mark may not be present if a pointer to the method is already reversed.
434 return ((unsigned int) bci)
435 ^ ((unsigned int) method->max_locals() << 2)
436 ^ ((unsigned int) method->code_size() << 4)
437 ^ ((unsigned int) method->size_of_parameters() << 6);
438 }
439
440
441 OopMapCache::OopMapCache() :
442 _mut(Mutex::leaf, "An OopMapCache lock", true)
443 {
444 _array = NEW_C_HEAP_ARRAY(OopMapCacheEntry, _size, mtClass);
445 // Cannot call flush for initialization, since flush
446 // will check if memory should be deallocated
447 for(int i = 0; i < _size; i++) _array[i].initialize();
448 NOT_PRODUCT(_total_memory_usage += sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
449 }
450
451
452 OopMapCache::~OopMapCache() {
453 assert(_array != NULL, "sanity check");
454 // Deallocate oop maps that are allocated out-of-line
455 flush();
456 // Deallocate array
457 NOT_PRODUCT(_total_memory_usage -= sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
458 FREE_C_HEAP_ARRAY(OopMapCacheEntry, _array);
459 }
460
461 OopMapCacheEntry* OopMapCache::entry_at(int i) const {
462 return &_array[i % _size];
463 }
464
465 void OopMapCache::flush() {
466 for (int i = 0; i < _size; i++) _array[i].flush();
467 }
468
469 void OopMapCache::flush_obsolete_entries() {
470 for (int i = 0; i < _size; i++)
471 if (!_array[i].is_empty() && _array[i].method()->is_old()) {
472 // Cache entry is occupied by an old redefined method and we don't want
473 // to pin it down so flush the entry.
474 RC_TRACE(0x08000000, ("flush: %s(%s): cached entry @%d",
475 _array[i].method()->name()->as_C_string(),
476 _array[i].method()->signature()->as_C_string(), i));
477
478 _array[i].flush();
479 }
480 }
481
482 void OopMapCache::lookup(methodHandle method,
483 int bci,
484 InterpreterOopMap* entry_for) const {
485 MutexLocker x(&_mut);
486
487 OopMapCacheEntry* entry = NULL;
488 int probe = hash_value_for(method, bci);
489
490 // Search hashtable for match
491 int i;
492 for(i = 0; i < _probe_depth; i++) {
493 entry = entry_at(probe + i);
494 if (entry->match(method, bci)) {
495 entry_for->resource_copy(entry);
496 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
497 return;
498 }
499 }
500
501 if (TraceOopMapGeneration) {
502 static int count = 0;
503 ResourceMark rm;
504 tty->print("%d - Computing oopmap at bci %d for ", ++count, bci);
505 method->print_value(); tty->cr();
506 }
507
508 // Entry is not in hashtable.
509 // Compute entry and return it
510
511 if (method->should_not_be_cached()) {
512 // It is either not safe or not a good idea to cache this Method*
513 // at this time. We give the caller of lookup() a copy of the
514 // interesting info via parameter entry_for, but we don't add it to
515 // the cache. See the gory details in Method*.cpp.
516 compute_one_oop_map(method, bci, entry_for);
517 return;
518 }
519
520 // First search for an empty slot
521 for(i = 0; i < _probe_depth; i++) {
522 entry = entry_at(probe + i);
523 if (entry->is_empty()) {
524 entry->fill(method, bci);
525 entry_for->resource_copy(entry);
526 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
527 return;
528 }
529 }
530
531 if (TraceOopMapGeneration) {
532 ResourceMark rm;
533 tty->print_cr("*** collision in oopmap cache - flushing item ***");
534 }
535
536 // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm
537 //entry_at(probe + _probe_depth - 1)->flush();
538 //for(i = _probe_depth - 1; i > 0; i--) {
539 // // Coping entry[i] = entry[i-1];
540 // OopMapCacheEntry *to = entry_at(probe + i);
541 // OopMapCacheEntry *from = entry_at(probe + i - 1);
542 // to->copy(from);
543 // }
544
545 assert(method->is_method(), "gaga");
546
547 entry = entry_at(probe + 0);
548 entry->fill(method, bci);
549
550 // Copy the newly cached entry to input parameter
551 entry_for->resource_copy(entry);
552
553 if (TraceOopMapGeneration) {
554 ResourceMark rm;
555 tty->print("Done with ");
556 method->print_value(); tty->cr();
557 }
558 assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
559
560 return;
561 }
562
563 void OopMapCache::compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry) {
564 // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack
565 OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1, mtClass);
566 tmp->initialize();
567 tmp->fill(method, bci);
568 entry->resource_copy(tmp);
569 FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp);
570 }