1 /*
2 * Copyright (c) 1997, 2010, 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 "incls/_precompiled.incl"
26 #include "incls/_deoptimization.cpp.incl"
27
28 bool DeoptimizationMarker::_is_active = false;
29
30 Deoptimization::UnrollBlock::UnrollBlock(int size_of_deoptimized_frame,
31 int caller_adjustment,
32 int number_of_frames,
33 intptr_t* frame_sizes,
34 address* frame_pcs,
35 BasicType return_type) {
36 _size_of_deoptimized_frame = size_of_deoptimized_frame;
37 _caller_adjustment = caller_adjustment;
38 _number_of_frames = number_of_frames;
39 _frame_sizes = frame_sizes;
40 _frame_pcs = frame_pcs;
41 _register_block = NEW_C_HEAP_ARRAY(intptr_t, RegisterMap::reg_count * 2);
42 _return_type = return_type;
43 // PD (x86 only)
44 _counter_temp = 0;
45 _initial_fp = 0;
46 _unpack_kind = 0;
47 _sender_sp_temp = 0;
48
49 _total_frame_sizes = size_of_frames();
50 }
51
52
53 Deoptimization::UnrollBlock::~UnrollBlock() {
54 FREE_C_HEAP_ARRAY(intptr_t, _frame_sizes);
55 FREE_C_HEAP_ARRAY(intptr_t, _frame_pcs);
56 FREE_C_HEAP_ARRAY(intptr_t, _register_block);
57 }
58
59
60 intptr_t* Deoptimization::UnrollBlock::value_addr_at(int register_number) const {
61 assert(register_number < RegisterMap::reg_count, "checking register number");
62 return &_register_block[register_number * 2];
63 }
64
65
66
67 int Deoptimization::UnrollBlock::size_of_frames() const {
68 // Acount first for the adjustment of the initial frame
69 int result = _caller_adjustment;
70 for (int index = 0; index < number_of_frames(); index++) {
71 result += frame_sizes()[index];
72 }
73 return result;
74 }
75
76
77 void Deoptimization::UnrollBlock::print() {
78 ttyLocker ttyl;
79 tty->print_cr("UnrollBlock");
80 tty->print_cr(" size_of_deoptimized_frame = %d", _size_of_deoptimized_frame);
81 tty->print( " frame_sizes: ");
82 for (int index = 0; index < number_of_frames(); index++) {
83 tty->print("%d ", frame_sizes()[index]);
84 }
85 tty->cr();
86 }
87
88
89 // In order to make fetch_unroll_info work properly with escape
90 // analysis, The method was changed from JRT_LEAF to JRT_BLOCK_ENTRY and
91 // ResetNoHandleMark and HandleMark were removed from it. The actual reallocation
92 // of previously eliminated objects occurs in realloc_objects, which is
93 // called from the method fetch_unroll_info_helper below.
94 JRT_BLOCK_ENTRY(Deoptimization::UnrollBlock*, Deoptimization::fetch_unroll_info(JavaThread* thread))
95 // It is actually ok to allocate handles in a leaf method. It causes no safepoints,
96 // but makes the entry a little slower. There is however a little dance we have to
97 // do in debug mode to get around the NoHandleMark code in the JRT_LEAF macro
98
99 // fetch_unroll_info() is called at the beginning of the deoptimization
100 // handler. Note this fact before we start generating temporary frames
101 // that can confuse an asynchronous stack walker. This counter is
102 // decremented at the end of unpack_frames().
103 thread->inc_in_deopt_handler();
104
105 return fetch_unroll_info_helper(thread);
106 JRT_END
107
108
109 // This is factored, since it is both called from a JRT_LEAF (deoptimization) and a JRT_ENTRY (uncommon_trap)
110 Deoptimization::UnrollBlock* Deoptimization::fetch_unroll_info_helper(JavaThread* thread) {
111
112 // Note: there is a safepoint safety issue here. No matter whether we enter
113 // via vanilla deopt or uncommon trap we MUST NOT stop at a safepoint once
114 // the vframeArray is created.
115 //
116
117 // Allocate our special deoptimization ResourceMark
118 DeoptResourceMark* dmark = new DeoptResourceMark(thread);
119 assert(thread->deopt_mark() == NULL, "Pending deopt!");
120 thread->set_deopt_mark(dmark);
121
122 frame stub_frame = thread->last_frame(); // Makes stack walkable as side effect
123 RegisterMap map(thread, true);
124 RegisterMap dummy_map(thread, false);
125 // Now get the deoptee with a valid map
126 frame deoptee = stub_frame.sender(&map);
127
128 // Create a growable array of VFrames where each VFrame represents an inlined
129 // Java frame. This storage is allocated with the usual system arena.
130 assert(deoptee.is_compiled_frame(), "Wrong frame type");
131 GrowableArray<compiledVFrame*>* chunk = new GrowableArray<compiledVFrame*>(10);
132 vframe* vf = vframe::new_vframe(&deoptee, &map, thread);
133 while (!vf->is_top()) {
134 assert(vf->is_compiled_frame(), "Wrong frame type");
135 chunk->push(compiledVFrame::cast(vf));
136 vf = vf->sender();
137 }
138 assert(vf->is_compiled_frame(), "Wrong frame type");
139 chunk->push(compiledVFrame::cast(vf));
140
141 #ifdef COMPILER2
142 // Reallocate the non-escaping objects and restore their fields. Then
143 // relock objects if synchronization on them was eliminated.
144 if (DoEscapeAnalysis) {
145 if (EliminateAllocations) {
146 assert (chunk->at(0)->scope() != NULL,"expect only compiled java frames");
147 GrowableArray<ScopeValue*>* objects = chunk->at(0)->scope()->objects();
148
149 // The flag return_oop() indicates call sites which return oop
150 // in compiled code. Such sites include java method calls,
151 // runtime calls (for example, used to allocate new objects/arrays
152 // on slow code path) and any other calls generated in compiled code.
153 // It is not guaranteed that we can get such information here only
154 // by analyzing bytecode in deoptimized frames. This is why this flag
155 // is set during method compilation (see Compile::Process_OopMap_Node()).
156 bool save_oop_result = chunk->at(0)->scope()->return_oop();
157 Handle return_value;
158 if (save_oop_result) {
159 // Reallocation may trigger GC. If deoptimization happened on return from
160 // call which returns oop we need to save it since it is not in oopmap.
161 oop result = deoptee.saved_oop_result(&map);
162 assert(result == NULL || result->is_oop(), "must be oop");
163 return_value = Handle(thread, result);
164 assert(Universe::heap()->is_in_or_null(result), "must be heap pointer");
165 if (TraceDeoptimization) {
166 tty->print_cr("SAVED OOP RESULT " INTPTR_FORMAT " in thread " INTPTR_FORMAT, result, thread);
167 }
168 }
169 bool reallocated = false;
170 if (objects != NULL) {
171 JRT_BLOCK
172 reallocated = realloc_objects(thread, &deoptee, objects, THREAD);
173 JRT_END
174 }
175 if (reallocated) {
176 reassign_fields(&deoptee, &map, objects);
177 #ifndef PRODUCT
178 if (TraceDeoptimization) {
179 ttyLocker ttyl;
180 tty->print_cr("REALLOC OBJECTS in thread " INTPTR_FORMAT, thread);
181 print_objects(objects);
182 }
183 #endif
184 }
185 if (save_oop_result) {
186 // Restore result.
187 deoptee.set_saved_oop_result(&map, return_value());
188 }
189 }
190 if (EliminateLocks) {
191 #ifndef PRODUCT
192 bool first = true;
193 #endif
194 for (int i = 0; i < chunk->length(); i++) {
195 compiledVFrame* cvf = chunk->at(i);
196 assert (cvf->scope() != NULL,"expect only compiled java frames");
197 GrowableArray<MonitorInfo*>* monitors = cvf->monitors();
198 if (monitors->is_nonempty()) {
199 relock_objects(monitors, thread);
200 #ifndef PRODUCT
201 if (TraceDeoptimization) {
202 ttyLocker ttyl;
203 for (int j = 0; j < monitors->length(); j++) {
204 MonitorInfo* mi = monitors->at(j);
205 if (mi->eliminated()) {
206 if (first) {
207 first = false;
208 tty->print_cr("RELOCK OBJECTS in thread " INTPTR_FORMAT, thread);
209 }
210 tty->print_cr(" object <" INTPTR_FORMAT "> locked", mi->owner());
211 }
212 }
213 }
214 #endif
215 }
216 }
217 }
218 }
219 #endif // COMPILER2
220 // Ensure that no safepoint is taken after pointers have been stored
221 // in fields of rematerialized objects. If a safepoint occurs from here on
222 // out the java state residing in the vframeArray will be missed.
223 No_Safepoint_Verifier no_safepoint;
224
225 vframeArray* array = create_vframeArray(thread, deoptee, &map, chunk);
226
227 assert(thread->vframe_array_head() == NULL, "Pending deopt!");;
228 thread->set_vframe_array_head(array);
229
230 // Now that the vframeArray has been created if we have any deferred local writes
231 // added by jvmti then we can free up that structure as the data is now in the
232 // vframeArray
233
234 if (thread->deferred_locals() != NULL) {
235 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = thread->deferred_locals();
236 int i = 0;
237 do {
238 // Because of inlining we could have multiple vframes for a single frame
239 // and several of the vframes could have deferred writes. Find them all.
240 if (list->at(i)->id() == array->original().id()) {
241 jvmtiDeferredLocalVariableSet* dlv = list->at(i);
242 list->remove_at(i);
243 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
244 delete dlv;
245 } else {
246 i++;
247 }
248 } while ( i < list->length() );
249 if (list->length() == 0) {
250 thread->set_deferred_locals(NULL);
251 // free the list and elements back to C heap.
252 delete list;
253 }
254
255 }
256
257 #ifndef SHARK
258 // Compute the caller frame based on the sender sp of stub_frame and stored frame sizes info.
259 CodeBlob* cb = stub_frame.cb();
260 // Verify we have the right vframeArray
261 assert(cb->frame_size() >= 0, "Unexpected frame size");
262 intptr_t* unpack_sp = stub_frame.sp() + cb->frame_size();
263
264 // If the deopt call site is a MethodHandle invoke call site we have
265 // to adjust the unpack_sp.
266 nmethod* deoptee_nm = deoptee.cb()->as_nmethod_or_null();
267 if (deoptee_nm != NULL && deoptee_nm->is_method_handle_return(deoptee.pc()))
268 unpack_sp = deoptee.unextended_sp();
269
270 #ifdef ASSERT
271 assert(cb->is_deoptimization_stub() || cb->is_uncommon_trap_stub(), "just checking");
272 Events::log("fetch unroll sp " INTPTR_FORMAT, unpack_sp);
273 #endif
274 #else
275 intptr_t* unpack_sp = stub_frame.sender(&dummy_map).unextended_sp();
276 #endif // !SHARK
277
278 // This is a guarantee instead of an assert because if vframe doesn't match
279 // we will unpack the wrong deoptimized frame and wind up in strange places
280 // where it will be very difficult to figure out what went wrong. Better
281 // to die an early death here than some very obscure death later when the
282 // trail is cold.
283 // Note: on ia64 this guarantee can be fooled by frames with no memory stack
284 // in that it will fail to detect a problem when there is one. This needs
285 // more work in tiger timeframe.
286 guarantee(array->unextended_sp() == unpack_sp, "vframe_array_head must contain the vframeArray to unpack");
287
288 int number_of_frames = array->frames();
289
290 // Compute the vframes' sizes. Note that frame_sizes[] entries are ordered from outermost to innermost
291 // virtual activation, which is the reverse of the elements in the vframes array.
292 intptr_t* frame_sizes = NEW_C_HEAP_ARRAY(intptr_t, number_of_frames);
293 // +1 because we always have an interpreter return address for the final slot.
294 address* frame_pcs = NEW_C_HEAP_ARRAY(address, number_of_frames + 1);
295 int callee_parameters = 0;
296 int callee_locals = 0;
297 int popframe_extra_args = 0;
298 // Create an interpreter return address for the stub to use as its return
299 // address so the skeletal frames are perfectly walkable
300 frame_pcs[number_of_frames] = Interpreter::deopt_entry(vtos, 0);
301
302 // PopFrame requires that the preserved incoming arguments from the recently-popped topmost
303 // activation be put back on the expression stack of the caller for reexecution
304 if (JvmtiExport::can_pop_frame() && thread->popframe_forcing_deopt_reexecution()) {
305 popframe_extra_args = in_words(thread->popframe_preserved_args_size_in_words());
306 }
307
308 //
309 // frame_sizes/frame_pcs[0] oldest frame (int or c2i)
310 // frame_sizes/frame_pcs[1] next oldest frame (int)
311 // frame_sizes/frame_pcs[n] youngest frame (int)
312 //
313 // Now a pc in frame_pcs is actually the return address to the frame's caller (a frame
314 // owns the space for the return address to it's caller). Confusing ain't it.
315 //
316 // The vframe array can address vframes with indices running from
317 // 0.._frames-1. Index 0 is the youngest frame and _frame - 1 is the oldest (root) frame.
318 // When we create the skeletal frames we need the oldest frame to be in the zero slot
319 // in the frame_sizes/frame_pcs so the assembly code can do a trivial walk.
320 // so things look a little strange in this loop.
321 //
322 for (int index = 0; index < array->frames(); index++ ) {
323 // frame[number_of_frames - 1 ] = on_stack_size(youngest)
324 // frame[number_of_frames - 2 ] = on_stack_size(sender(youngest))
325 // frame[number_of_frames - 3 ] = on_stack_size(sender(sender(youngest)))
326 frame_sizes[number_of_frames - 1 - index] = BytesPerWord * array->element(index)->on_stack_size(callee_parameters,
327 callee_locals,
328 index == 0,
329 popframe_extra_args);
330 // This pc doesn't have to be perfect just good enough to identify the frame
331 // as interpreted so the skeleton frame will be walkable
332 // The correct pc will be set when the skeleton frame is completely filled out
333 // The final pc we store in the loop is wrong and will be overwritten below
334 frame_pcs[number_of_frames - 1 - index ] = Interpreter::deopt_entry(vtos, 0) - frame::pc_return_offset;
335
336 callee_parameters = array->element(index)->method()->size_of_parameters();
337 callee_locals = array->element(index)->method()->max_locals();
338 popframe_extra_args = 0;
339 }
340
341 // Compute whether the root vframe returns a float or double value.
342 BasicType return_type;
343 {
344 HandleMark hm;
345 methodHandle method(thread, array->element(0)->method());
346 Bytecode_invoke* invoke = Bytecode_invoke_at_check(method, array->element(0)->bci());
347 return_type = (invoke != NULL) ? invoke->result_type(thread) : T_ILLEGAL;
348 }
349
350 // Compute information for handling adapters and adjusting the frame size of the caller.
351 int caller_adjustment = 0;
352
353 // Find the current pc for sender of the deoptee. Since the sender may have been deoptimized
354 // itself since the deoptee vframeArray was created we must get a fresh value of the pc rather
355 // than simply use array->sender.pc(). This requires us to walk the current set of frames
356 //
357 frame deopt_sender = stub_frame.sender(&dummy_map); // First is the deoptee frame
358 deopt_sender = deopt_sender.sender(&dummy_map); // Now deoptee caller
359
360 // Compute the amount the oldest interpreter frame will have to adjust
361 // its caller's stack by. If the caller is a compiled frame then
362 // we pretend that the callee has no parameters so that the
363 // extension counts for the full amount of locals and not just
364 // locals-parms. This is because without a c2i adapter the parm
365 // area as created by the compiled frame will not be usable by
366 // the interpreter. (Depending on the calling convention there
367 // may not even be enough space).
368
369 // QQQ I'd rather see this pushed down into last_frame_adjust
370 // and have it take the sender (aka caller).
371
372 if (deopt_sender.is_compiled_frame()) {
373 caller_adjustment = last_frame_adjust(0, callee_locals);
374 } else if (callee_locals > callee_parameters) {
375 // The caller frame may need extending to accommodate
376 // non-parameter locals of the first unpacked interpreted frame.
377 // Compute that adjustment.
378 caller_adjustment = last_frame_adjust(callee_parameters, callee_locals);
379 }
380
381
382 // If the sender is deoptimized the we must retrieve the address of the handler
383 // since the frame will "magically" show the original pc before the deopt
384 // and we'd undo the deopt.
385
386 frame_pcs[0] = deopt_sender.raw_pc();
387
388 #ifndef SHARK
389 assert(CodeCache::find_blob_unsafe(frame_pcs[0]) != NULL, "bad pc");
390 #endif // SHARK
391
392 UnrollBlock* info = new UnrollBlock(array->frame_size() * BytesPerWord,
393 caller_adjustment * BytesPerWord,
394 number_of_frames,
395 frame_sizes,
396 frame_pcs,
397 return_type);
398 #if defined(IA32) || defined(AMD64)
399 // We need a way to pass fp to the unpacking code so the skeletal frames
400 // come out correct. This is only needed for x86 because of c2 using ebp
401 // as an allocatable register. So this update is useless (and harmless)
402 // on the other platforms. It would be nice to do this in a different
403 // way but even the old style deoptimization had a problem with deriving
404 // this value. NEEDS_CLEANUP
405 // Note: now that c1 is using c2's deopt blob we must do this on all
406 // x86 based platforms
407 intptr_t** fp_addr = (intptr_t**) (((address)info) + info->initial_fp_offset_in_bytes());
408 *fp_addr = array->sender().fp(); // was adapter_caller
409 #endif /* IA32 || AMD64 */
410
411 if (array->frames() > 1) {
412 if (VerifyStack && TraceDeoptimization) {
413 tty->print_cr("Deoptimizing method containing inlining");
414 }
415 }
416
417 array->set_unroll_block(info);
418 return info;
419 }
420
421 // Called to cleanup deoptimization data structures in normal case
422 // after unpacking to stack and when stack overflow error occurs
423 void Deoptimization::cleanup_deopt_info(JavaThread *thread,
424 vframeArray *array) {
425
426 // Get array if coming from exception
427 if (array == NULL) {
428 array = thread->vframe_array_head();
429 }
430 thread->set_vframe_array_head(NULL);
431
432 // Free the previous UnrollBlock
433 vframeArray* old_array = thread->vframe_array_last();
434 thread->set_vframe_array_last(array);
435
436 if (old_array != NULL) {
437 UnrollBlock* old_info = old_array->unroll_block();
438 old_array->set_unroll_block(NULL);
439 delete old_info;
440 delete old_array;
441 }
442
443 // Deallocate any resource creating in this routine and any ResourceObjs allocated
444 // inside the vframeArray (StackValueCollections)
445
446 delete thread->deopt_mark();
447 thread->set_deopt_mark(NULL);
448
449
450 if (JvmtiExport::can_pop_frame()) {
451 #ifndef CC_INTERP
452 // Regardless of whether we entered this routine with the pending
453 // popframe condition bit set, we should always clear it now
454 thread->clear_popframe_condition();
455 #else
456 // C++ interpeter will clear has_pending_popframe when it enters
457 // with method_resume. For deopt_resume2 we clear it now.
458 if (thread->popframe_forcing_deopt_reexecution())
459 thread->clear_popframe_condition();
460 #endif /* CC_INTERP */
461 }
462
463 // unpack_frames() is called at the end of the deoptimization handler
464 // and (in C2) at the end of the uncommon trap handler. Note this fact
465 // so that an asynchronous stack walker can work again. This counter is
466 // incremented at the beginning of fetch_unroll_info() and (in C2) at
467 // the beginning of uncommon_trap().
468 thread->dec_in_deopt_handler();
469 }
470
471
472 // Return BasicType of value being returned
473 JRT_LEAF(BasicType, Deoptimization::unpack_frames(JavaThread* thread, int exec_mode))
474
475 // We are already active int he special DeoptResourceMark any ResourceObj's we
476 // allocate will be freed at the end of the routine.
477
478 // It is actually ok to allocate handles in a leaf method. It causes no safepoints,
479 // but makes the entry a little slower. There is however a little dance we have to
480 // do in debug mode to get around the NoHandleMark code in the JRT_LEAF macro
481 ResetNoHandleMark rnhm; // No-op in release/product versions
482 HandleMark hm;
483
484 frame stub_frame = thread->last_frame();
485
486 // Since the frame to unpack is the top frame of this thread, the vframe_array_head
487 // must point to the vframeArray for the unpack frame.
488 vframeArray* array = thread->vframe_array_head();
489
490 #ifndef PRODUCT
491 if (TraceDeoptimization) {
492 tty->print_cr("DEOPT UNPACKING thread " INTPTR_FORMAT " vframeArray " INTPTR_FORMAT " mode %d", thread, array, exec_mode);
493 }
494 #endif
495
496 UnrollBlock* info = array->unroll_block();
497
498 // Unpack the interpreter frames and any adapter frame (c2 only) we might create.
499 array->unpack_to_stack(stub_frame, exec_mode);
500
501 BasicType bt = info->return_type();
502
503 // If we have an exception pending, claim that the return type is an oop
504 // so the deopt_blob does not overwrite the exception_oop.
505
506 if (exec_mode == Unpack_exception)
507 bt = T_OBJECT;
508
509 // Cleanup thread deopt data
510 cleanup_deopt_info(thread, array);
511
512 #ifndef PRODUCT
513 if (VerifyStack) {
514 ResourceMark res_mark;
515
516 // Verify that the just-unpacked frames match the interpreter's
517 // notions of expression stack and locals
518 vframeArray* cur_array = thread->vframe_array_last();
519 RegisterMap rm(thread, false);
520 rm.set_include_argument_oops(false);
521 bool is_top_frame = true;
522 int callee_size_of_parameters = 0;
523 int callee_max_locals = 0;
524 for (int i = 0; i < cur_array->frames(); i++) {
525 vframeArrayElement* el = cur_array->element(i);
526 frame* iframe = el->iframe();
527 guarantee(iframe->is_interpreted_frame(), "Wrong frame type");
528
529 // Get the oop map for this bci
530 InterpreterOopMap mask;
531 int cur_invoke_parameter_size = 0;
532 bool try_next_mask = false;
533 int next_mask_expression_stack_size = -1;
534 int top_frame_expression_stack_adjustment = 0;
535 methodHandle mh(thread, iframe->interpreter_frame_method());
536 OopMapCache::compute_one_oop_map(mh, iframe->interpreter_frame_bci(), &mask);
537 BytecodeStream str(mh);
538 str.set_start(iframe->interpreter_frame_bci());
539 int max_bci = mh->code_size();
540 // Get to the next bytecode if possible
541 assert(str.bci() < max_bci, "bci in interpreter frame out of bounds");
542 // Check to see if we can grab the number of outgoing arguments
543 // at an uncommon trap for an invoke (where the compiler
544 // generates debug info before the invoke has executed)
545 Bytecodes::Code cur_code = str.next();
546 if (cur_code == Bytecodes::_invokevirtual ||
547 cur_code == Bytecodes::_invokespecial ||
548 cur_code == Bytecodes::_invokestatic ||
549 cur_code == Bytecodes::_invokeinterface) {
550 Bytecode_invoke* invoke = Bytecode_invoke_at(mh, iframe->interpreter_frame_bci());
551 symbolHandle signature(thread, invoke->signature());
552 ArgumentSizeComputer asc(signature);
553 cur_invoke_parameter_size = asc.size();
554 if (cur_code != Bytecodes::_invokestatic) {
555 // Add in receiver
556 ++cur_invoke_parameter_size;
557 }
558 }
559 if (str.bci() < max_bci) {
560 Bytecodes::Code bc = str.next();
561 if (bc >= 0) {
562 // The interpreter oop map generator reports results before
563 // the current bytecode has executed except in the case of
564 // calls. It seems to be hard to tell whether the compiler
565 // has emitted debug information matching the "state before"
566 // a given bytecode or the state after, so we try both
567 switch (cur_code) {
568 case Bytecodes::_invokevirtual:
569 case Bytecodes::_invokespecial:
570 case Bytecodes::_invokestatic:
571 case Bytecodes::_invokeinterface:
572 case Bytecodes::_athrow:
573 break;
574 default: {
575 InterpreterOopMap next_mask;
576 OopMapCache::compute_one_oop_map(mh, str.bci(), &next_mask);
577 next_mask_expression_stack_size = next_mask.expression_stack_size();
578 // Need to subtract off the size of the result type of
579 // the bytecode because this is not described in the
580 // debug info but returned to the interpreter in the TOS
581 // caching register
582 BasicType bytecode_result_type = Bytecodes::result_type(cur_code);
583 if (bytecode_result_type != T_ILLEGAL) {
584 top_frame_expression_stack_adjustment = type2size[bytecode_result_type];
585 }
586 assert(top_frame_expression_stack_adjustment >= 0, "");
587 try_next_mask = true;
588 break;
589 }
590 }
591 }
592 }
593
594 // Verify stack depth and oops in frame
595 // This assertion may be dependent on the platform we're running on and may need modification (tested on x86 and sparc)
596 if (!(
597 /* SPARC */
598 (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + callee_size_of_parameters) ||
599 /* x86 */
600 (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + callee_max_locals) ||
601 (try_next_mask &&
602 (iframe->interpreter_frame_expression_stack_size() == (next_mask_expression_stack_size -
603 top_frame_expression_stack_adjustment))) ||
604 (is_top_frame && (exec_mode == Unpack_exception) && iframe->interpreter_frame_expression_stack_size() == 0) ||
605 (is_top_frame && (exec_mode == Unpack_uncommon_trap || exec_mode == Unpack_reexecute) &&
606 (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + cur_invoke_parameter_size))
607 )) {
608 ttyLocker ttyl;
609
610 // Print out some information that will help us debug the problem
611 tty->print_cr("Wrong number of expression stack elements during deoptimization");
612 tty->print_cr(" Error occurred while verifying frame %d (0..%d, 0 is topmost)", i, cur_array->frames() - 1);
613 tty->print_cr(" Fabricated interpreter frame had %d expression stack elements",
614 iframe->interpreter_frame_expression_stack_size());
615 tty->print_cr(" Interpreter oop map had %d expression stack elements", mask.expression_stack_size());
616 tty->print_cr(" try_next_mask = %d", try_next_mask);
617 tty->print_cr(" next_mask_expression_stack_size = %d", next_mask_expression_stack_size);
618 tty->print_cr(" callee_size_of_parameters = %d", callee_size_of_parameters);
619 tty->print_cr(" callee_max_locals = %d", callee_max_locals);
620 tty->print_cr(" top_frame_expression_stack_adjustment = %d", top_frame_expression_stack_adjustment);
621 tty->print_cr(" exec_mode = %d", exec_mode);
622 tty->print_cr(" cur_invoke_parameter_size = %d", cur_invoke_parameter_size);
623 tty->print_cr(" Thread = " INTPTR_FORMAT ", thread ID = " UINTX_FORMAT, thread, thread->osthread()->thread_id());
624 tty->print_cr(" Interpreted frames:");
625 for (int k = 0; k < cur_array->frames(); k++) {
626 vframeArrayElement* el = cur_array->element(k);
627 tty->print_cr(" %s (bci %d)", el->method()->name_and_sig_as_C_string(), el->bci());
628 }
629 cur_array->print_on_2(tty);
630 guarantee(false, "wrong number of expression stack elements during deopt");
631 }
632 VerifyOopClosure verify;
633 iframe->oops_interpreted_do(&verify, &rm, false);
634 callee_size_of_parameters = mh->size_of_parameters();
635 callee_max_locals = mh->max_locals();
636 is_top_frame = false;
637 }
638 }
639 #endif /* !PRODUCT */
640
641
642 return bt;
643 JRT_END
644
645
646 int Deoptimization::deoptimize_dependents() {
647 Threads::deoptimized_wrt_marked_nmethods();
648 return 0;
649 }
650
651
652 #ifdef COMPILER2
653 bool Deoptimization::realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS) {
654 Handle pending_exception(thread->pending_exception());
655 const char* exception_file = thread->exception_file();
656 int exception_line = thread->exception_line();
657 thread->clear_pending_exception();
658
659 for (int i = 0; i < objects->length(); i++) {
660 assert(objects->at(i)->is_object(), "invalid debug information");
661 ObjectValue* sv = (ObjectValue*) objects->at(i);
662
663 KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()());
664 oop obj = NULL;
665
666 if (k->oop_is_instance()) {
667 instanceKlass* ik = instanceKlass::cast(k());
668 obj = ik->allocate_instance(CHECK_(false));
669 } else if (k->oop_is_typeArray()) {
670 typeArrayKlass* ak = typeArrayKlass::cast(k());
671 assert(sv->field_size() % type2size[ak->element_type()] == 0, "non-integral array length");
672 int len = sv->field_size() / type2size[ak->element_type()];
673 obj = ak->allocate(len, CHECK_(false));
674 } else if (k->oop_is_objArray()) {
675 objArrayKlass* ak = objArrayKlass::cast(k());
676 obj = ak->allocate(sv->field_size(), CHECK_(false));
677 }
678
679 assert(obj != NULL, "allocation failed");
680 assert(sv->value().is_null(), "redundant reallocation");
681 sv->set_value(obj);
682 }
683
684 if (pending_exception.not_null()) {
685 thread->set_pending_exception(pending_exception(), exception_file, exception_line);
686 }
687
688 return true;
689 }
690
691 // This assumes that the fields are stored in ObjectValue in the same order
692 // they are yielded by do_nonstatic_fields.
693 class FieldReassigner: public FieldClosure {
694 frame* _fr;
695 RegisterMap* _reg_map;
696 ObjectValue* _sv;
697 instanceKlass* _ik;
698 oop _obj;
699
700 int _i;
701 public:
702 FieldReassigner(frame* fr, RegisterMap* reg_map, ObjectValue* sv, oop obj) :
703 _fr(fr), _reg_map(reg_map), _sv(sv), _obj(obj), _i(0) {}
704
705 int i() const { return _i; }
706
707
708 void do_field(fieldDescriptor* fd) {
709 intptr_t val;
710 StackValue* value =
711 StackValue::create_stack_value(_fr, _reg_map, _sv->field_at(i()));
712 int offset = fd->offset();
713 switch (fd->field_type()) {
714 case T_OBJECT: case T_ARRAY:
715 assert(value->type() == T_OBJECT, "Agreement.");
716 _obj->obj_field_put(offset, value->get_obj()());
717 break;
718
719 case T_LONG: case T_DOUBLE: {
720 assert(value->type() == T_INT, "Agreement.");
721 StackValue* low =
722 StackValue::create_stack_value(_fr, _reg_map, _sv->field_at(++_i));
723 #ifdef _LP64
724 jlong res = (jlong)low->get_int();
725 #else
726 #ifdef SPARC
727 // For SPARC we have to swap high and low words.
728 jlong res = jlong_from((jint)low->get_int(), (jint)value->get_int());
729 #else
730 jlong res = jlong_from((jint)value->get_int(), (jint)low->get_int());
731 #endif //SPARC
732 #endif
733 _obj->long_field_put(offset, res);
734 break;
735 }
736 // Have to cast to INT (32 bits) pointer to avoid little/big-endian problem.
737 case T_INT: case T_FLOAT: // 4 bytes.
738 assert(value->type() == T_INT, "Agreement.");
739 val = value->get_int();
740 _obj->int_field_put(offset, (jint)*((jint*)&val));
741 break;
742
743 case T_SHORT: case T_CHAR: // 2 bytes
744 assert(value->type() == T_INT, "Agreement.");
745 val = value->get_int();
746 _obj->short_field_put(offset, (jshort)*((jint*)&val));
747 break;
748
749 case T_BOOLEAN: case T_BYTE: // 1 byte
750 assert(value->type() == T_INT, "Agreement.");
751 val = value->get_int();
752 _obj->bool_field_put(offset, (jboolean)*((jint*)&val));
753 break;
754
755 default:
756 ShouldNotReachHere();
757 }
758 _i++;
759 }
760 };
761
762 // restore elements of an eliminated type array
763 void Deoptimization::reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type) {
764 int index = 0;
765 intptr_t val;
766
767 for (int i = 0; i < sv->field_size(); i++) {
768 StackValue* value = StackValue::create_stack_value(fr, reg_map, sv->field_at(i));
769 switch(type) {
770 case T_LONG: case T_DOUBLE: {
771 assert(value->type() == T_INT, "Agreement.");
772 StackValue* low =
773 StackValue::create_stack_value(fr, reg_map, sv->field_at(++i));
774 #ifdef _LP64
775 jlong res = (jlong)low->get_int();
776 #else
777 #ifdef SPARC
778 // For SPARC we have to swap high and low words.
779 jlong res = jlong_from((jint)low->get_int(), (jint)value->get_int());
780 #else
781 jlong res = jlong_from((jint)value->get_int(), (jint)low->get_int());
782 #endif //SPARC
783 #endif
784 obj->long_at_put(index, res);
785 break;
786 }
787
788 // Have to cast to INT (32 bits) pointer to avoid little/big-endian problem.
789 case T_INT: case T_FLOAT: // 4 bytes.
790 assert(value->type() == T_INT, "Agreement.");
791 val = value->get_int();
792 obj->int_at_put(index, (jint)*((jint*)&val));
793 break;
794
795 case T_SHORT: case T_CHAR: // 2 bytes
796 assert(value->type() == T_INT, "Agreement.");
797 val = value->get_int();
798 obj->short_at_put(index, (jshort)*((jint*)&val));
799 break;
800
801 case T_BOOLEAN: case T_BYTE: // 1 byte
802 assert(value->type() == T_INT, "Agreement.");
803 val = value->get_int();
804 obj->bool_at_put(index, (jboolean)*((jint*)&val));
805 break;
806
807 default:
808 ShouldNotReachHere();
809 }
810 index++;
811 }
812 }
813
814
815 // restore fields of an eliminated object array
816 void Deoptimization::reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj) {
817 for (int i = 0; i < sv->field_size(); i++) {
818 StackValue* value = StackValue::create_stack_value(fr, reg_map, sv->field_at(i));
819 assert(value->type() == T_OBJECT, "object element expected");
820 obj->obj_at_put(i, value->get_obj()());
821 }
822 }
823
824
825 // restore fields of all eliminated objects and arrays
826 void Deoptimization::reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects) {
827 for (int i = 0; i < objects->length(); i++) {
828 ObjectValue* sv = (ObjectValue*) objects->at(i);
829 KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()());
830 Handle obj = sv->value();
831 assert(obj.not_null(), "reallocation was missed");
832
833 if (k->oop_is_instance()) {
834 instanceKlass* ik = instanceKlass::cast(k());
835 FieldReassigner reassign(fr, reg_map, sv, obj());
836 ik->do_nonstatic_fields(&reassign);
837 } else if (k->oop_is_typeArray()) {
838 typeArrayKlass* ak = typeArrayKlass::cast(k());
839 reassign_type_array_elements(fr, reg_map, sv, (typeArrayOop) obj(), ak->element_type());
840 } else if (k->oop_is_objArray()) {
841 reassign_object_array_elements(fr, reg_map, sv, (objArrayOop) obj());
842 }
843 }
844 }
845
846
847 // relock objects for which synchronization was eliminated
848 void Deoptimization::relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread) {
849 for (int i = 0; i < monitors->length(); i++) {
850 MonitorInfo* mon_info = monitors->at(i);
851 if (mon_info->eliminated()) {
852 assert(mon_info->owner() != NULL, "reallocation was missed");
853 Handle obj = Handle(mon_info->owner());
854 markOop mark = obj->mark();
855 if (UseBiasedLocking && mark->has_bias_pattern()) {
856 // New allocated objects may have the mark set to anonymously biased.
857 // Also the deoptimized method may called methods with synchronization
858 // where the thread-local object is bias locked to the current thread.
859 assert(mark->is_biased_anonymously() ||
860 mark->biased_locker() == thread, "should be locked to current thread");
861 // Reset mark word to unbiased prototype.
862 markOop unbiased_prototype = markOopDesc::prototype()->set_age(mark->age());
863 obj->set_mark(unbiased_prototype);
864 }
865 BasicLock* lock = mon_info->lock();
866 ObjectSynchronizer::slow_enter(obj, lock, thread);
867 }
868 assert(mon_info->owner()->is_locked(), "object must be locked now");
869 }
870 }
871
872
873 #ifndef PRODUCT
874 // print information about reallocated objects
875 void Deoptimization::print_objects(GrowableArray<ScopeValue*>* objects) {
876 fieldDescriptor fd;
877
878 for (int i = 0; i < objects->length(); i++) {
879 ObjectValue* sv = (ObjectValue*) objects->at(i);
880 KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()());
881 Handle obj = sv->value();
882
883 tty->print(" object <" INTPTR_FORMAT "> of type ", sv->value()());
884 k->as_klassOop()->print_value();
885 tty->print(" allocated (%d bytes)", obj->size() * HeapWordSize);
886 tty->cr();
887
888 if (Verbose) {
889 k->oop_print_on(obj(), tty);
890 }
891 }
892 }
893 #endif
894 #endif // COMPILER2
895
896 vframeArray* Deoptimization::create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk) {
897
898 #ifndef PRODUCT
899 if (TraceDeoptimization) {
900 ttyLocker ttyl;
901 tty->print("DEOPT PACKING thread " INTPTR_FORMAT " ", thread);
902 fr.print_on(tty);
903 tty->print_cr(" Virtual frames (innermost first):");
904 for (int index = 0; index < chunk->length(); index++) {
905 compiledVFrame* vf = chunk->at(index);
906 tty->print(" %2d - ", index);
907 vf->print_value();
908 int bci = chunk->at(index)->raw_bci();
909 const char* code_name;
910 if (bci == SynchronizationEntryBCI) {
911 code_name = "sync entry";
912 } else {
913 Bytecodes::Code code = Bytecodes::code_at(vf->method(), bci);
914 code_name = Bytecodes::name(code);
915 }
916 tty->print(" - %s", code_name);
917 tty->print_cr(" @ bci %d ", bci);
918 if (Verbose) {
919 vf->print();
920 tty->cr();
921 }
922 }
923 }
924 #endif
925
926 // Register map for next frame (used for stack crawl). We capture
927 // the state of the deopt'ing frame's caller. Thus if we need to
928 // stuff a C2I adapter we can properly fill in the callee-save
929 // register locations.
930 frame caller = fr.sender(reg_map);
931 int frame_size = caller.sp() - fr.sp();
932
933 frame sender = caller;
934
935 // Since the Java thread being deoptimized will eventually adjust it's own stack,
936 // the vframeArray containing the unpacking information is allocated in the C heap.
937 // For Compiler1, the caller of the deoptimized frame is saved for use by unpack_frames().
938 vframeArray* array = vframeArray::allocate(thread, frame_size, chunk, reg_map, sender, caller, fr);
939
940 // Compare the vframeArray to the collected vframes
941 assert(array->structural_compare(thread, chunk), "just checking");
942 Events::log("# vframes = %d", (intptr_t)chunk->length());
943
944 #ifndef PRODUCT
945 if (TraceDeoptimization) {
946 ttyLocker ttyl;
947 tty->print_cr(" Created vframeArray " INTPTR_FORMAT, array);
948 }
949 #endif // PRODUCT
950
951 return array;
952 }
953
954
955 static void collect_monitors(compiledVFrame* cvf, GrowableArray<Handle>* objects_to_revoke) {
956 GrowableArray<MonitorInfo*>* monitors = cvf->monitors();
957 for (int i = 0; i < monitors->length(); i++) {
958 MonitorInfo* mon_info = monitors->at(i);
959 if (!mon_info->eliminated() && mon_info->owner() != NULL) {
960 objects_to_revoke->append(Handle(mon_info->owner()));
961 }
962 }
963 }
964
965
966 void Deoptimization::revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map) {
967 if (!UseBiasedLocking) {
968 return;
969 }
970
971 GrowableArray<Handle>* objects_to_revoke = new GrowableArray<Handle>();
972
973 // Unfortunately we don't have a RegisterMap available in most of
974 // the places we want to call this routine so we need to walk the
975 // stack again to update the register map.
976 if (map == NULL || !map->update_map()) {
977 StackFrameStream sfs(thread, true);
978 bool found = false;
979 while (!found && !sfs.is_done()) {
980 frame* cur = sfs.current();
981 sfs.next();
982 found = cur->id() == fr.id();
983 }
984 assert(found, "frame to be deoptimized not found on target thread's stack");
985 map = sfs.register_map();
986 }
987
988 vframe* vf = vframe::new_vframe(&fr, map, thread);
989 compiledVFrame* cvf = compiledVFrame::cast(vf);
990 // Revoke monitors' biases in all scopes
991 while (!cvf->is_top()) {
992 collect_monitors(cvf, objects_to_revoke);
993 cvf = compiledVFrame::cast(cvf->sender());
994 }
995 collect_monitors(cvf, objects_to_revoke);
996
997 if (SafepointSynchronize::is_at_safepoint()) {
998 BiasedLocking::revoke_at_safepoint(objects_to_revoke);
999 } else {
1000 BiasedLocking::revoke(objects_to_revoke);
1001 }
1002 }
1003
1004
1005 void Deoptimization::revoke_biases_of_monitors(CodeBlob* cb) {
1006 if (!UseBiasedLocking) {
1007 return;
1008 }
1009
1010 assert(SafepointSynchronize::is_at_safepoint(), "must only be called from safepoint");
1011 GrowableArray<Handle>* objects_to_revoke = new GrowableArray<Handle>();
1012 for (JavaThread* jt = Threads::first(); jt != NULL ; jt = jt->next()) {
1013 if (jt->has_last_Java_frame()) {
1014 StackFrameStream sfs(jt, true);
1015 while (!sfs.is_done()) {
1016 frame* cur = sfs.current();
1017 if (cb->contains(cur->pc())) {
1018 vframe* vf = vframe::new_vframe(cur, sfs.register_map(), jt);
1019 compiledVFrame* cvf = compiledVFrame::cast(vf);
1020 // Revoke monitors' biases in all scopes
1021 while (!cvf->is_top()) {
1022 collect_monitors(cvf, objects_to_revoke);
1023 cvf = compiledVFrame::cast(cvf->sender());
1024 }
1025 collect_monitors(cvf, objects_to_revoke);
1026 }
1027 sfs.next();
1028 }
1029 }
1030 }
1031 BiasedLocking::revoke_at_safepoint(objects_to_revoke);
1032 }
1033
1034
1035 void Deoptimization::deoptimize_single_frame(JavaThread* thread, frame fr) {
1036 assert(fr.can_be_deoptimized(), "checking frame type");
1037
1038 gather_statistics(Reason_constraint, Action_none, Bytecodes::_illegal);
1039
1040 EventMark m("Deoptimization (pc=" INTPTR_FORMAT ", sp=" INTPTR_FORMAT ")", fr.pc(), fr.id());
1041
1042 // Patch the nmethod so that when execution returns to it we will
1043 // deopt the execution state and return to the interpreter.
1044 fr.deoptimize(thread);
1045 }
1046
1047 void Deoptimization::deoptimize(JavaThread* thread, frame fr, RegisterMap *map) {
1048 // Deoptimize only if the frame comes from compile code.
1049 // Do not deoptimize the frame which is already patched
1050 // during the execution of the loops below.
1051 if (!fr.is_compiled_frame() || fr.is_deoptimized_frame()) {
1052 return;
1053 }
1054 ResourceMark rm;
1055 DeoptimizationMarker dm;
1056 if (UseBiasedLocking) {
1057 revoke_biases_of_monitors(thread, fr, map);
1058 }
1059 deoptimize_single_frame(thread, fr);
1060
1061 }
1062
1063
1064 void Deoptimization::deoptimize_frame(JavaThread* thread, intptr_t* id) {
1065 // Compute frame and register map based on thread and sp.
1066 RegisterMap reg_map(thread, UseBiasedLocking);
1067 frame fr = thread->last_frame();
1068 while (fr.id() != id) {
1069 fr = fr.sender(®_map);
1070 }
1071 deoptimize(thread, fr, ®_map);
1072 }
1073
1074
1075 // JVMTI PopFrame support
1076 JRT_LEAF(void, Deoptimization::popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address))
1077 {
1078 thread->popframe_preserve_args(in_ByteSize(bytes_to_save), start_address);
1079 }
1080 JRT_END
1081
1082
1083 #if defined(COMPILER2) || defined(SHARK)
1084 void Deoptimization::load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS) {
1085 // in case of an unresolved klass entry, load the class.
1086 if (constant_pool->tag_at(index).is_unresolved_klass()) {
1087 klassOop tk = constant_pool->klass_at(index, CHECK);
1088 return;
1089 }
1090
1091 if (!constant_pool->tag_at(index).is_symbol()) return;
1092
1093 Handle class_loader (THREAD, instanceKlass::cast(constant_pool->pool_holder())->class_loader());
1094 symbolHandle symbol (THREAD, constant_pool->symbol_at(index));
1095
1096 // class name?
1097 if (symbol->byte_at(0) != '(') {
1098 Handle protection_domain (THREAD, Klass::cast(constant_pool->pool_holder())->protection_domain());
1099 SystemDictionary::resolve_or_null(symbol, class_loader, protection_domain, CHECK);
1100 return;
1101 }
1102
1103 // then it must be a signature!
1104 for (SignatureStream ss(symbol); !ss.is_done(); ss.next()) {
1105 if (ss.is_object()) {
1106 symbolOop s = ss.as_symbol(CHECK);
1107 symbolHandle class_name (THREAD, s);
1108 Handle protection_domain (THREAD, Klass::cast(constant_pool->pool_holder())->protection_domain());
1109 SystemDictionary::resolve_or_null(class_name, class_loader, protection_domain, CHECK);
1110 }
1111 }
1112 }
1113
1114
1115 void Deoptimization::load_class_by_index(constantPoolHandle constant_pool, int index) {
1116 EXCEPTION_MARK;
1117 load_class_by_index(constant_pool, index, THREAD);
1118 if (HAS_PENDING_EXCEPTION) {
1119 // Exception happened during classloading. We ignore the exception here, since it
1120 // is going to be rethrown since the current activation is going to be deoptimzied and
1121 // the interpreter will re-execute the bytecode.
1122 CLEAR_PENDING_EXCEPTION;
1123 }
1124 }
1125
1126 JRT_ENTRY(void, Deoptimization::uncommon_trap_inner(JavaThread* thread, jint trap_request)) {
1127 HandleMark hm;
1128
1129 // uncommon_trap() is called at the beginning of the uncommon trap
1130 // handler. Note this fact before we start generating temporary frames
1131 // that can confuse an asynchronous stack walker. This counter is
1132 // decremented at the end of unpack_frames().
1133 thread->inc_in_deopt_handler();
1134
1135 // We need to update the map if we have biased locking.
1136 RegisterMap reg_map(thread, UseBiasedLocking);
1137 frame stub_frame = thread->last_frame();
1138 frame fr = stub_frame.sender(®_map);
1139 // Make sure the calling nmethod is not getting deoptimized and removed
1140 // before we are done with it.
1141 nmethodLocker nl(fr.pc());
1142
1143 {
1144 ResourceMark rm;
1145
1146 // Revoke biases of any monitors in the frame to ensure we can migrate them
1147 revoke_biases_of_monitors(thread, fr, ®_map);
1148
1149 DeoptReason reason = trap_request_reason(trap_request);
1150 DeoptAction action = trap_request_action(trap_request);
1151 jint unloaded_class_index = trap_request_index(trap_request); // CP idx or -1
1152
1153 Events::log("Uncommon trap occurred @" INTPTR_FORMAT " unloaded_class_index = %d", fr.pc(), (int) trap_request);
1154 vframe* vf = vframe::new_vframe(&fr, ®_map, thread);
1155 compiledVFrame* cvf = compiledVFrame::cast(vf);
1156
1157 nmethod* nm = cvf->code();
1158
1159 ScopeDesc* trap_scope = cvf->scope();
1160 methodHandle trap_method = trap_scope->method();
1161 int trap_bci = trap_scope->bci();
1162 Bytecodes::Code trap_bc = Bytecode_at(trap_method->bcp_from(trap_bci))->java_code();
1163
1164 // Record this event in the histogram.
1165 gather_statistics(reason, action, trap_bc);
1166
1167 // Ensure that we can record deopt. history:
1168 bool create_if_missing = ProfileTraps;
1169
1170 methodDataHandle trap_mdo
1171 (THREAD, get_method_data(thread, trap_method, create_if_missing));
1172
1173 // Print a bunch of diagnostics, if requested.
1174 if (TraceDeoptimization || LogCompilation) {
1175 ResourceMark rm;
1176 ttyLocker ttyl;
1177 char buf[100];
1178 if (xtty != NULL) {
1179 xtty->begin_head("uncommon_trap thread='" UINTX_FORMAT"' %s",
1180 os::current_thread_id(),
1181 format_trap_request(buf, sizeof(buf), trap_request));
1182 nm->log_identity(xtty);
1183 }
1184 symbolHandle class_name;
1185 bool unresolved = false;
1186 if (unloaded_class_index >= 0) {
1187 constantPoolHandle constants (THREAD, trap_method->constants());
1188 if (constants->tag_at(unloaded_class_index).is_unresolved_klass()) {
1189 class_name = symbolHandle(THREAD,
1190 constants->klass_name_at(unloaded_class_index));
1191 unresolved = true;
1192 if (xtty != NULL)
1193 xtty->print(" unresolved='1'");
1194 } else if (constants->tag_at(unloaded_class_index).is_symbol()) {
1195 class_name = symbolHandle(THREAD,
1196 constants->symbol_at(unloaded_class_index));
1197 }
1198 if (xtty != NULL)
1199 xtty->name(class_name);
1200 }
1201 if (xtty != NULL && trap_mdo.not_null()) {
1202 // Dump the relevant MDO state.
1203 // This is the deopt count for the current reason, any previous
1204 // reasons or recompiles seen at this point.
1205 int dcnt = trap_mdo->trap_count(reason);
1206 if (dcnt != 0)
1207 xtty->print(" count='%d'", dcnt);
1208 ProfileData* pdata = trap_mdo->bci_to_data(trap_bci);
1209 int dos = (pdata == NULL)? 0: pdata->trap_state();
1210 if (dos != 0) {
1211 xtty->print(" state='%s'", format_trap_state(buf, sizeof(buf), dos));
1212 if (trap_state_is_recompiled(dos)) {
1213 int recnt2 = trap_mdo->overflow_recompile_count();
1214 if (recnt2 != 0)
1215 xtty->print(" recompiles2='%d'", recnt2);
1216 }
1217 }
1218 }
1219 if (xtty != NULL) {
1220 xtty->stamp();
1221 xtty->end_head();
1222 }
1223 if (TraceDeoptimization) { // make noise on the tty
1224 tty->print("Uncommon trap occurred in");
1225 nm->method()->print_short_name(tty);
1226 tty->print(" (@" INTPTR_FORMAT ") thread=%d reason=%s action=%s unloaded_class_index=%d",
1227 fr.pc(),
1228 (int) os::current_thread_id(),
1229 trap_reason_name(reason),
1230 trap_action_name(action),
1231 unloaded_class_index);
1232 if (class_name.not_null()) {
1233 tty->print(unresolved ? " unresolved class: " : " symbol: ");
1234 class_name->print_symbol_on(tty);
1235 }
1236 tty->cr();
1237 }
1238 if (xtty != NULL) {
1239 // Log the precise location of the trap.
1240 for (ScopeDesc* sd = trap_scope; ; sd = sd->sender()) {
1241 xtty->begin_elem("jvms bci='%d'", sd->bci());
1242 xtty->method(sd->method());
1243 xtty->end_elem();
1244 if (sd->is_top()) break;
1245 }
1246 xtty->tail("uncommon_trap");
1247 }
1248 }
1249 // (End diagnostic printout.)
1250
1251 // Load class if necessary
1252 if (unloaded_class_index >= 0) {
1253 constantPoolHandle constants(THREAD, trap_method->constants());
1254 load_class_by_index(constants, unloaded_class_index);
1255 }
1256
1257 // Flush the nmethod if necessary and desirable.
1258 //
1259 // We need to avoid situations where we are re-flushing the nmethod
1260 // because of a hot deoptimization site. Repeated flushes at the same
1261 // point need to be detected by the compiler and avoided. If the compiler
1262 // cannot avoid them (or has a bug and "refuses" to avoid them), this
1263 // module must take measures to avoid an infinite cycle of recompilation
1264 // and deoptimization. There are several such measures:
1265 //
1266 // 1. If a recompilation is ordered a second time at some site X
1267 // and for the same reason R, the action is adjusted to 'reinterpret',
1268 // to give the interpreter time to exercise the method more thoroughly.
1269 // If this happens, the method's overflow_recompile_count is incremented.
1270 //
1271 // 2. If the compiler fails to reduce the deoptimization rate, then
1272 // the method's overflow_recompile_count will begin to exceed the set
1273 // limit PerBytecodeRecompilationCutoff. If this happens, the action
1274 // is adjusted to 'make_not_compilable', and the method is abandoned
1275 // to the interpreter. This is a performance hit for hot methods,
1276 // but is better than a disastrous infinite cycle of recompilations.
1277 // (Actually, only the method containing the site X is abandoned.)
1278 //
1279 // 3. In parallel with the previous measures, if the total number of
1280 // recompilations of a method exceeds the much larger set limit
1281 // PerMethodRecompilationCutoff, the method is abandoned.
1282 // This should only happen if the method is very large and has
1283 // many "lukewarm" deoptimizations. The code which enforces this
1284 // limit is elsewhere (class nmethod, class methodOopDesc).
1285 //
1286 // Note that the per-BCI 'is_recompiled' bit gives the compiler one chance
1287 // to recompile at each bytecode independently of the per-BCI cutoff.
1288 //
1289 // The decision to update code is up to the compiler, and is encoded
1290 // in the Action_xxx code. If the compiler requests Action_none
1291 // no trap state is changed, no compiled code is changed, and the
1292 // computation suffers along in the interpreter.
1293 //
1294 // The other action codes specify various tactics for decompilation
1295 // and recompilation. Action_maybe_recompile is the loosest, and
1296 // allows the compiled code to stay around until enough traps are seen,
1297 // and until the compiler gets around to recompiling the trapping method.
1298 //
1299 // The other actions cause immediate removal of the present code.
1300
1301 bool update_trap_state = true;
1302 bool make_not_entrant = false;
1303 bool make_not_compilable = false;
1304 bool reprofile = false;
1305 switch (action) {
1306 case Action_none:
1307 // Keep the old code.
1308 update_trap_state = false;
1309 break;
1310 case Action_maybe_recompile:
1311 // Do not need to invalidate the present code, but we can
1312 // initiate another
1313 // Start compiler without (necessarily) invalidating the nmethod.
1314 // The system will tolerate the old code, but new code should be
1315 // generated when possible.
1316 break;
1317 case Action_reinterpret:
1318 // Go back into the interpreter for a while, and then consider
1319 // recompiling form scratch.
1320 make_not_entrant = true;
1321 // Reset invocation counter for outer most method.
1322 // This will allow the interpreter to exercise the bytecodes
1323 // for a while before recompiling.
1324 // By contrast, Action_make_not_entrant is immediate.
1325 //
1326 // Note that the compiler will track null_check, null_assert,
1327 // range_check, and class_check events and log them as if they
1328 // had been traps taken from compiled code. This will update
1329 // the MDO trap history so that the next compilation will
1330 // properly detect hot trap sites.
1331 reprofile = true;
1332 break;
1333 case Action_make_not_entrant:
1334 // Request immediate recompilation, and get rid of the old code.
1335 // Make them not entrant, so next time they are called they get
1336 // recompiled. Unloaded classes are loaded now so recompile before next
1337 // time they are called. Same for uninitialized. The interpreter will
1338 // link the missing class, if any.
1339 make_not_entrant = true;
1340 break;
1341 case Action_make_not_compilable:
1342 // Give up on compiling this method at all.
1343 make_not_entrant = true;
1344 make_not_compilable = true;
1345 break;
1346 default:
1347 ShouldNotReachHere();
1348 }
1349
1350 // Setting +ProfileTraps fixes the following, on all platforms:
1351 // 4852688: ProfileInterpreter is off by default for ia64. The result is
1352 // infinite heroic-opt-uncommon-trap/deopt/recompile cycles, since the
1353 // recompile relies on a methodDataOop to record heroic opt failures.
1354
1355 // Whether the interpreter is producing MDO data or not, we also need
1356 // to use the MDO to detect hot deoptimization points and control
1357 // aggressive optimization.
1358 bool inc_recompile_count = false;
1359 ProfileData* pdata = NULL;
1360 if (ProfileTraps && update_trap_state && trap_mdo.not_null()) {
1361 assert(trap_mdo() == get_method_data(thread, trap_method, false), "sanity");
1362 uint this_trap_count = 0;
1363 bool maybe_prior_trap = false;
1364 bool maybe_prior_recompile = false;
1365 pdata = query_update_method_data(trap_mdo, trap_bci, reason,
1366 //outputs:
1367 this_trap_count,
1368 maybe_prior_trap,
1369 maybe_prior_recompile);
1370 // Because the interpreter also counts null, div0, range, and class
1371 // checks, these traps from compiled code are double-counted.
1372 // This is harmless; it just means that the PerXTrapLimit values
1373 // are in effect a little smaller than they look.
1374
1375 DeoptReason per_bc_reason = reason_recorded_per_bytecode_if_any(reason);
1376 if (per_bc_reason != Reason_none) {
1377 // Now take action based on the partially known per-BCI history.
1378 if (maybe_prior_trap
1379 && this_trap_count >= (uint)PerBytecodeTrapLimit) {
1380 // If there are too many traps at this BCI, force a recompile.
1381 // This will allow the compiler to see the limit overflow, and
1382 // take corrective action, if possible. The compiler generally
1383 // does not use the exact PerBytecodeTrapLimit value, but instead
1384 // changes its tactics if it sees any traps at all. This provides
1385 // a little hysteresis, delaying a recompile until a trap happens
1386 // several times.
1387 //
1388 // Actually, since there is only one bit of counter per BCI,
1389 // the possible per-BCI counts are {0,1,(per-method count)}.
1390 // This produces accurate results if in fact there is only
1391 // one hot trap site, but begins to get fuzzy if there are
1392 // many sites. For example, if there are ten sites each
1393 // trapping two or more times, they each get the blame for
1394 // all of their traps.
1395 make_not_entrant = true;
1396 }
1397
1398 // Detect repeated recompilation at the same BCI, and enforce a limit.
1399 if (make_not_entrant && maybe_prior_recompile) {
1400 // More than one recompile at this point.
1401 inc_recompile_count = maybe_prior_trap;
1402 }
1403 } else {
1404 // For reasons which are not recorded per-bytecode, we simply
1405 // force recompiles unconditionally.
1406 // (Note that PerMethodRecompilationCutoff is enforced elsewhere.)
1407 make_not_entrant = true;
1408 }
1409
1410 // Go back to the compiler if there are too many traps in this method.
1411 if (this_trap_count >= (uint)PerMethodTrapLimit) {
1412 // If there are too many traps in this method, force a recompile.
1413 // This will allow the compiler to see the limit overflow, and
1414 // take corrective action, if possible.
1415 // (This condition is an unlikely backstop only, because the
1416 // PerBytecodeTrapLimit is more likely to take effect first,
1417 // if it is applicable.)
1418 make_not_entrant = true;
1419 }
1420
1421 // Here's more hysteresis: If there has been a recompile at
1422 // this trap point already, run the method in the interpreter
1423 // for a while to exercise it more thoroughly.
1424 if (make_not_entrant && maybe_prior_recompile && maybe_prior_trap) {
1425 reprofile = true;
1426 }
1427
1428 }
1429
1430 // Take requested actions on the method:
1431
1432 // Recompile
1433 if (make_not_entrant) {
1434 if (!nm->make_not_entrant()) {
1435 return; // the call did not change nmethod's state
1436 }
1437
1438 if (pdata != NULL) {
1439 // Record the recompilation event, if any.
1440 int tstate0 = pdata->trap_state();
1441 int tstate1 = trap_state_set_recompiled(tstate0, true);
1442 if (tstate1 != tstate0)
1443 pdata->set_trap_state(tstate1);
1444 }
1445 }
1446
1447 if (inc_recompile_count) {
1448 trap_mdo->inc_overflow_recompile_count();
1449 if ((uint)trap_mdo->overflow_recompile_count() >
1450 (uint)PerBytecodeRecompilationCutoff) {
1451 // Give up on the method containing the bad BCI.
1452 if (trap_method() == nm->method()) {
1453 make_not_compilable = true;
1454 } else {
1455 trap_method->set_not_compilable(CompLevel_full_optimization);
1456 // But give grace to the enclosing nm->method().
1457 }
1458 }
1459 }
1460
1461 // Reprofile
1462 if (reprofile) {
1463 CompilationPolicy::policy()->reprofile(trap_scope, nm->is_osr_method());
1464 }
1465
1466 // Give up compiling
1467 if (make_not_compilable && !nm->method()->is_not_compilable(CompLevel_full_optimization)) {
1468 assert(make_not_entrant, "consistent");
1469 nm->method()->set_not_compilable(CompLevel_full_optimization);
1470 }
1471
1472 } // Free marked resources
1473
1474 }
1475 JRT_END
1476
1477 methodDataOop
1478 Deoptimization::get_method_data(JavaThread* thread, methodHandle m,
1479 bool create_if_missing) {
1480 Thread* THREAD = thread;
1481 methodDataOop mdo = m()->method_data();
1482 if (mdo == NULL && create_if_missing && !HAS_PENDING_EXCEPTION) {
1483 // Build an MDO. Ignore errors like OutOfMemory;
1484 // that simply means we won't have an MDO to update.
1485 methodOopDesc::build_interpreter_method_data(m, THREAD);
1486 if (HAS_PENDING_EXCEPTION) {
1487 assert((PENDING_EXCEPTION->is_a(SystemDictionary::OutOfMemoryError_klass())), "we expect only an OOM error here");
1488 CLEAR_PENDING_EXCEPTION;
1489 }
1490 mdo = m()->method_data();
1491 }
1492 return mdo;
1493 }
1494
1495 ProfileData*
1496 Deoptimization::query_update_method_data(methodDataHandle trap_mdo,
1497 int trap_bci,
1498 Deoptimization::DeoptReason reason,
1499 //outputs:
1500 uint& ret_this_trap_count,
1501 bool& ret_maybe_prior_trap,
1502 bool& ret_maybe_prior_recompile) {
1503 uint prior_trap_count = trap_mdo->trap_count(reason);
1504 uint this_trap_count = trap_mdo->inc_trap_count(reason);
1505
1506 // If the runtime cannot find a place to store trap history,
1507 // it is estimated based on the general condition of the method.
1508 // If the method has ever been recompiled, or has ever incurred
1509 // a trap with the present reason , then this BCI is assumed
1510 // (pessimistically) to be the culprit.
1511 bool maybe_prior_trap = (prior_trap_count != 0);
1512 bool maybe_prior_recompile = (trap_mdo->decompile_count() != 0);
1513 ProfileData* pdata = NULL;
1514
1515
1516 // For reasons which are recorded per bytecode, we check per-BCI data.
1517 DeoptReason per_bc_reason = reason_recorded_per_bytecode_if_any(reason);
1518 if (per_bc_reason != Reason_none) {
1519 // Find the profile data for this BCI. If there isn't one,
1520 // try to allocate one from the MDO's set of spares.
1521 // This will let us detect a repeated trap at this point.
1522 pdata = trap_mdo->allocate_bci_to_data(trap_bci);
1523
1524 if (pdata != NULL) {
1525 // Query the trap state of this profile datum.
1526 int tstate0 = pdata->trap_state();
1527 if (!trap_state_has_reason(tstate0, per_bc_reason))
1528 maybe_prior_trap = false;
1529 if (!trap_state_is_recompiled(tstate0))
1530 maybe_prior_recompile = false;
1531
1532 // Update the trap state of this profile datum.
1533 int tstate1 = tstate0;
1534 // Record the reason.
1535 tstate1 = trap_state_add_reason(tstate1, per_bc_reason);
1536 // Store the updated state on the MDO, for next time.
1537 if (tstate1 != tstate0)
1538 pdata->set_trap_state(tstate1);
1539 } else {
1540 if (LogCompilation && xtty != NULL) {
1541 ttyLocker ttyl;
1542 // Missing MDP? Leave a small complaint in the log.
1543 xtty->elem("missing_mdp bci='%d'", trap_bci);
1544 }
1545 }
1546 }
1547
1548 // Return results:
1549 ret_this_trap_count = this_trap_count;
1550 ret_maybe_prior_trap = maybe_prior_trap;
1551 ret_maybe_prior_recompile = maybe_prior_recompile;
1552 return pdata;
1553 }
1554
1555 void
1556 Deoptimization::update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason) {
1557 ResourceMark rm;
1558 // Ignored outputs:
1559 uint ignore_this_trap_count;
1560 bool ignore_maybe_prior_trap;
1561 bool ignore_maybe_prior_recompile;
1562 query_update_method_data(trap_mdo, trap_bci,
1563 (DeoptReason)reason,
1564 ignore_this_trap_count,
1565 ignore_maybe_prior_trap,
1566 ignore_maybe_prior_recompile);
1567 }
1568
1569 Deoptimization::UnrollBlock* Deoptimization::uncommon_trap(JavaThread* thread, jint trap_request) {
1570
1571 // Still in Java no safepoints
1572 {
1573 // This enters VM and may safepoint
1574 uncommon_trap_inner(thread, trap_request);
1575 }
1576 return fetch_unroll_info_helper(thread);
1577 }
1578
1579 // Local derived constants.
1580 // Further breakdown of DataLayout::trap_state, as promised by DataLayout.
1581 const int DS_REASON_MASK = DataLayout::trap_mask >> 1;
1582 const int DS_RECOMPILE_BIT = DataLayout::trap_mask - DS_REASON_MASK;
1583
1584 //---------------------------trap_state_reason---------------------------------
1585 Deoptimization::DeoptReason
1586 Deoptimization::trap_state_reason(int trap_state) {
1587 // This assert provides the link between the width of DataLayout::trap_bits
1588 // and the encoding of "recorded" reasons. It ensures there are enough
1589 // bits to store all needed reasons in the per-BCI MDO profile.
1590 assert(DS_REASON_MASK >= Reason_RECORDED_LIMIT, "enough bits");
1591 int recompile_bit = (trap_state & DS_RECOMPILE_BIT);
1592 trap_state -= recompile_bit;
1593 if (trap_state == DS_REASON_MASK) {
1594 return Reason_many;
1595 } else {
1596 assert((int)Reason_none == 0, "state=0 => Reason_none");
1597 return (DeoptReason)trap_state;
1598 }
1599 }
1600 //-------------------------trap_state_has_reason-------------------------------
1601 int Deoptimization::trap_state_has_reason(int trap_state, int reason) {
1602 assert(reason_is_recorded_per_bytecode((DeoptReason)reason), "valid reason");
1603 assert(DS_REASON_MASK >= Reason_RECORDED_LIMIT, "enough bits");
1604 int recompile_bit = (trap_state & DS_RECOMPILE_BIT);
1605 trap_state -= recompile_bit;
1606 if (trap_state == DS_REASON_MASK) {
1607 return -1; // true, unspecifically (bottom of state lattice)
1608 } else if (trap_state == reason) {
1609 return 1; // true, definitely
1610 } else if (trap_state == 0) {
1611 return 0; // false, definitely (top of state lattice)
1612 } else {
1613 return 0; // false, definitely
1614 }
1615 }
1616 //-------------------------trap_state_add_reason-------------------------------
1617 int Deoptimization::trap_state_add_reason(int trap_state, int reason) {
1618 assert(reason_is_recorded_per_bytecode((DeoptReason)reason) || reason == Reason_many, "valid reason");
1619 int recompile_bit = (trap_state & DS_RECOMPILE_BIT);
1620 trap_state -= recompile_bit;
1621 if (trap_state == DS_REASON_MASK) {
1622 return trap_state + recompile_bit; // already at state lattice bottom
1623 } else if (trap_state == reason) {
1624 return trap_state + recompile_bit; // the condition is already true
1625 } else if (trap_state == 0) {
1626 return reason + recompile_bit; // no condition has yet been true
1627 } else {
1628 return DS_REASON_MASK + recompile_bit; // fall to state lattice bottom
1629 }
1630 }
1631 //-----------------------trap_state_is_recompiled------------------------------
1632 bool Deoptimization::trap_state_is_recompiled(int trap_state) {
1633 return (trap_state & DS_RECOMPILE_BIT) != 0;
1634 }
1635 //-----------------------trap_state_set_recompiled-----------------------------
1636 int Deoptimization::trap_state_set_recompiled(int trap_state, bool z) {
1637 if (z) return trap_state | DS_RECOMPILE_BIT;
1638 else return trap_state & ~DS_RECOMPILE_BIT;
1639 }
1640 //---------------------------format_trap_state---------------------------------
1641 // This is used for debugging and diagnostics, including hotspot.log output.
1642 const char* Deoptimization::format_trap_state(char* buf, size_t buflen,
1643 int trap_state) {
1644 DeoptReason reason = trap_state_reason(trap_state);
1645 bool recomp_flag = trap_state_is_recompiled(trap_state);
1646 // Re-encode the state from its decoded components.
1647 int decoded_state = 0;
1648 if (reason_is_recorded_per_bytecode(reason) || reason == Reason_many)
1649 decoded_state = trap_state_add_reason(decoded_state, reason);
1650 if (recomp_flag)
1651 decoded_state = trap_state_set_recompiled(decoded_state, recomp_flag);
1652 // If the state re-encodes properly, format it symbolically.
1653 // Because this routine is used for debugging and diagnostics,
1654 // be robust even if the state is a strange value.
1655 size_t len;
1656 if (decoded_state != trap_state) {
1657 // Random buggy state that doesn't decode??
1658 len = jio_snprintf(buf, buflen, "#%d", trap_state);
1659 } else {
1660 len = jio_snprintf(buf, buflen, "%s%s",
1661 trap_reason_name(reason),
1662 recomp_flag ? " recompiled" : "");
1663 }
1664 if (len >= buflen)
1665 buf[buflen-1] = '\0';
1666 return buf;
1667 }
1668
1669
1670 //--------------------------------statics--------------------------------------
1671 Deoptimization::DeoptAction Deoptimization::_unloaded_action
1672 = Deoptimization::Action_reinterpret;
1673 const char* Deoptimization::_trap_reason_name[Reason_LIMIT] = {
1674 // Note: Keep this in sync. with enum DeoptReason.
1675 "none",
1676 "null_check",
1677 "null_assert",
1678 "range_check",
1679 "class_check",
1680 "array_check",
1681 "intrinsic",
1682 "bimorphic",
1683 "unloaded",
1684 "uninitialized",
1685 "unreached",
1686 "unhandled",
1687 "constraint",
1688 "div0_check",
1689 "age",
1690 "predicate"
1691 };
1692 const char* Deoptimization::_trap_action_name[Action_LIMIT] = {
1693 // Note: Keep this in sync. with enum DeoptAction.
1694 "none",
1695 "maybe_recompile",
1696 "reinterpret",
1697 "make_not_entrant",
1698 "make_not_compilable"
1699 };
1700
1701 const char* Deoptimization::trap_reason_name(int reason) {
1702 if (reason == Reason_many) return "many";
1703 if ((uint)reason < Reason_LIMIT)
1704 return _trap_reason_name[reason];
1705 static char buf[20];
1706 sprintf(buf, "reason%d", reason);
1707 return buf;
1708 }
1709 const char* Deoptimization::trap_action_name(int action) {
1710 if ((uint)action < Action_LIMIT)
1711 return _trap_action_name[action];
1712 static char buf[20];
1713 sprintf(buf, "action%d", action);
1714 return buf;
1715 }
1716
1717 // This is used for debugging and diagnostics, including hotspot.log output.
1718 const char* Deoptimization::format_trap_request(char* buf, size_t buflen,
1719 int trap_request) {
1720 jint unloaded_class_index = trap_request_index(trap_request);
1721 const char* reason = trap_reason_name(trap_request_reason(trap_request));
1722 const char* action = trap_action_name(trap_request_action(trap_request));
1723 size_t len;
1724 if (unloaded_class_index < 0) {
1725 len = jio_snprintf(buf, buflen, "reason='%s' action='%s'",
1726 reason, action);
1727 } else {
1728 len = jio_snprintf(buf, buflen, "reason='%s' action='%s' index='%d'",
1729 reason, action, unloaded_class_index);
1730 }
1731 if (len >= buflen)
1732 buf[buflen-1] = '\0';
1733 return buf;
1734 }
1735
1736 juint Deoptimization::_deoptimization_hist
1737 [Deoptimization::Reason_LIMIT]
1738 [1 + Deoptimization::Action_LIMIT]
1739 [Deoptimization::BC_CASE_LIMIT]
1740 = {0};
1741
1742 enum {
1743 LSB_BITS = 8,
1744 LSB_MASK = right_n_bits(LSB_BITS)
1745 };
1746
1747 void Deoptimization::gather_statistics(DeoptReason reason, DeoptAction action,
1748 Bytecodes::Code bc) {
1749 assert(reason >= 0 && reason < Reason_LIMIT, "oob");
1750 assert(action >= 0 && action < Action_LIMIT, "oob");
1751 _deoptimization_hist[Reason_none][0][0] += 1; // total
1752 _deoptimization_hist[reason][0][0] += 1; // per-reason total
1753 juint* cases = _deoptimization_hist[reason][1+action];
1754 juint* bc_counter_addr = NULL;
1755 juint bc_counter = 0;
1756 // Look for an unused counter, or an exact match to this BC.
1757 if (bc != Bytecodes::_illegal) {
1758 for (int bc_case = 0; bc_case < BC_CASE_LIMIT; bc_case++) {
1759 juint* counter_addr = &cases[bc_case];
1760 juint counter = *counter_addr;
1761 if ((counter == 0 && bc_counter_addr == NULL)
1762 || (Bytecodes::Code)(counter & LSB_MASK) == bc) {
1763 // this counter is either free or is already devoted to this BC
1764 bc_counter_addr = counter_addr;
1765 bc_counter = counter | bc;
1766 }
1767 }
1768 }
1769 if (bc_counter_addr == NULL) {
1770 // Overflow, or no given bytecode.
1771 bc_counter_addr = &cases[BC_CASE_LIMIT-1];
1772 bc_counter = (*bc_counter_addr & ~LSB_MASK); // clear LSB
1773 }
1774 *bc_counter_addr = bc_counter + (1 << LSB_BITS);
1775 }
1776
1777 jint Deoptimization::total_deoptimization_count() {
1778 return _deoptimization_hist[Reason_none][0][0];
1779 }
1780
1781 jint Deoptimization::deoptimization_count(DeoptReason reason) {
1782 assert(reason >= 0 && reason < Reason_LIMIT, "oob");
1783 return _deoptimization_hist[reason][0][0];
1784 }
1785
1786 void Deoptimization::print_statistics() {
1787 juint total = total_deoptimization_count();
1788 juint account = total;
1789 if (total != 0) {
1790 ttyLocker ttyl;
1791 if (xtty != NULL) xtty->head("statistics type='deoptimization'");
1792 tty->print_cr("Deoptimization traps recorded:");
1793 #define PRINT_STAT_LINE(name, r) \
1794 tty->print_cr(" %4d (%4.1f%%) %s", (int)(r), ((r) * 100.0) / total, name);
1795 PRINT_STAT_LINE("total", total);
1796 // For each non-zero entry in the histogram, print the reason,
1797 // the action, and (if specifically known) the type of bytecode.
1798 for (int reason = 0; reason < Reason_LIMIT; reason++) {
1799 for (int action = 0; action < Action_LIMIT; action++) {
1800 juint* cases = _deoptimization_hist[reason][1+action];
1801 for (int bc_case = 0; bc_case < BC_CASE_LIMIT; bc_case++) {
1802 juint counter = cases[bc_case];
1803 if (counter != 0) {
1804 char name[1*K];
1805 Bytecodes::Code bc = (Bytecodes::Code)(counter & LSB_MASK);
1806 if (bc_case == BC_CASE_LIMIT && (int)bc == 0)
1807 bc = Bytecodes::_illegal;
1808 sprintf(name, "%s/%s/%s",
1809 trap_reason_name(reason),
1810 trap_action_name(action),
1811 Bytecodes::is_defined(bc)? Bytecodes::name(bc): "other");
1812 juint r = counter >> LSB_BITS;
1813 tty->print_cr(" %40s: " UINT32_FORMAT " (%.1f%%)", name, r, (r * 100.0) / total);
1814 account -= r;
1815 }
1816 }
1817 }
1818 }
1819 if (account != 0) {
1820 PRINT_STAT_LINE("unaccounted", account);
1821 }
1822 #undef PRINT_STAT_LINE
1823 if (xtty != NULL) xtty->tail("statistics");
1824 }
1825 }
1826 #else // COMPILER2 || SHARK
1827
1828
1829 // Stubs for C1 only system.
1830 bool Deoptimization::trap_state_is_recompiled(int trap_state) {
1831 return false;
1832 }
1833
1834 const char* Deoptimization::trap_reason_name(int reason) {
1835 return "unknown";
1836 }
1837
1838 void Deoptimization::print_statistics() {
1839 // no output
1840 }
1841
1842 void
1843 Deoptimization::update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason) {
1844 // no udpate
1845 }
1846
1847 int Deoptimization::trap_state_has_reason(int trap_state, int reason) {
1848 return 0;
1849 }
1850
1851 void Deoptimization::gather_statistics(DeoptReason reason, DeoptAction action,
1852 Bytecodes::Code bc) {
1853 // no update
1854 }
1855
1856 const char* Deoptimization::format_trap_state(char* buf, size_t buflen,
1857 int trap_state) {
1858 jio_snprintf(buf, buflen, "#%d", trap_state);
1859 return buf;
1860 }
1861
1862 #endif // COMPILER2 || SHARK