1 /*
2 * Copyright (c) 2001, 2012, 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 "compiler/compileLog.hpp"
27 #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
28 #include "gc_implementation/g1/heapRegion.hpp"
29 #include "gc_interface/collectedHeap.hpp"
30 #include "memory/barrierSet.hpp"
31 #include "memory/cardTableModRefBS.hpp"
32 #include "opto/addnode.hpp"
33 #include "opto/graphKit.hpp"
34 #include "opto/idealKit.hpp"
35 #include "opto/locknode.hpp"
36 #include "opto/machnode.hpp"
37 #include "opto/parse.hpp"
38 #include "opto/rootnode.hpp"
39 #include "opto/runtime.hpp"
40 #include "runtime/deoptimization.hpp"
41 #include "runtime/sharedRuntime.hpp"
42
43 //----------------------------GraphKit-----------------------------------------
44 // Main utility constructor.
45 GraphKit::GraphKit(JVMState* jvms)
46 : Phase(Phase::Parser),
47 _env(C->env()),
48 _gvn(*C->initial_gvn())
49 {
50 _exceptions = jvms->map()->next_exception();
51 if (_exceptions != NULL) jvms->map()->set_next_exception(NULL);
52 set_jvms(jvms);
53 }
54
55 // Private constructor for parser.
56 GraphKit::GraphKit()
57 : Phase(Phase::Parser),
58 _env(C->env()),
59 _gvn(*C->initial_gvn())
60 {
61 _exceptions = NULL;
62 set_map(NULL);
63 debug_only(_sp = -99);
64 debug_only(set_bci(-99));
65 }
66
67
68
69 //---------------------------clean_stack---------------------------------------
70 // Clear away rubbish from the stack area of the JVM state.
71 // This destroys any arguments that may be waiting on the stack.
72 void GraphKit::clean_stack(int from_sp) {
73 SafePointNode* map = this->map();
74 JVMState* jvms = this->jvms();
75 int stk_size = jvms->stk_size();
76 int stkoff = jvms->stkoff();
77 Node* top = this->top();
78 for (int i = from_sp; i < stk_size; i++) {
79 if (map->in(stkoff + i) != top) {
80 map->set_req(stkoff + i, top);
81 }
82 }
83 }
84
85
86 //--------------------------------sync_jvms-----------------------------------
87 // Make sure our current jvms agrees with our parse state.
88 JVMState* GraphKit::sync_jvms() const {
89 JVMState* jvms = this->jvms();
90 jvms->set_bci(bci()); // Record the new bci in the JVMState
91 jvms->set_sp(sp()); // Record the new sp in the JVMState
92 assert(jvms_in_sync(), "jvms is now in sync");
93 return jvms;
94 }
95
96 //--------------------------------sync_jvms_for_reexecute---------------------
97 // Make sure our current jvms agrees with our parse state. This version
98 // uses the reexecute_sp for reexecuting bytecodes.
99 JVMState* GraphKit::sync_jvms_for_reexecute() {
100 JVMState* jvms = this->jvms();
101 jvms->set_bci(bci()); // Record the new bci in the JVMState
102 jvms->set_sp(reexecute_sp()); // Record the new sp in the JVMState
103 return jvms;
104 }
105
106 #ifdef ASSERT
107 bool GraphKit::jvms_in_sync() const {
108 Parse* parse = is_Parse();
109 if (parse == NULL) {
110 if (bci() != jvms()->bci()) return false;
111 if (sp() != (int)jvms()->sp()) return false;
112 return true;
113 }
114 if (jvms()->method() != parse->method()) return false;
115 if (jvms()->bci() != parse->bci()) return false;
116 int jvms_sp = jvms()->sp();
117 if (jvms_sp != parse->sp()) return false;
118 int jvms_depth = jvms()->depth();
119 if (jvms_depth != parse->depth()) return false;
120 return true;
121 }
122
123 // Local helper checks for special internal merge points
124 // used to accumulate and merge exception states.
125 // They are marked by the region's in(0) edge being the map itself.
126 // Such merge points must never "escape" into the parser at large,
127 // until they have been handed to gvn.transform.
128 static bool is_hidden_merge(Node* reg) {
129 if (reg == NULL) return false;
130 if (reg->is_Phi()) {
131 reg = reg->in(0);
132 if (reg == NULL) return false;
133 }
134 return reg->is_Region() && reg->in(0) != NULL && reg->in(0)->is_Root();
135 }
136
137 void GraphKit::verify_map() const {
138 if (map() == NULL) return; // null map is OK
139 assert(map()->req() <= jvms()->endoff(), "no extra garbage on map");
140 assert(!map()->has_exceptions(), "call add_exception_states_from 1st");
141 assert(!is_hidden_merge(control()), "call use_exception_state, not set_map");
142 }
143
144 void GraphKit::verify_exception_state(SafePointNode* ex_map) {
145 assert(ex_map->next_exception() == NULL, "not already part of a chain");
146 assert(has_saved_ex_oop(ex_map), "every exception state has an ex_oop");
147 }
148 #endif
149
150 //---------------------------stop_and_kill_map---------------------------------
151 // Set _map to NULL, signalling a stop to further bytecode execution.
152 // First smash the current map's control to a constant, to mark it dead.
153 void GraphKit::stop_and_kill_map() {
154 SafePointNode* dead_map = stop();
155 if (dead_map != NULL) {
156 dead_map->disconnect_inputs(NULL, C); // Mark the map as killed.
157 assert(dead_map->is_killed(), "must be so marked");
158 }
159 }
160
161
162 //--------------------------------stopped--------------------------------------
163 // Tell if _map is NULL, or control is top.
164 bool GraphKit::stopped() {
165 if (map() == NULL) return true;
166 else if (control() == top()) return true;
167 else return false;
168 }
169
170
171 //-----------------------------has_ex_handler----------------------------------
172 // Tell if this method or any caller method has exception handlers.
173 bool GraphKit::has_ex_handler() {
174 for (JVMState* jvmsp = jvms(); jvmsp != NULL; jvmsp = jvmsp->caller()) {
175 if (jvmsp->has_method() && jvmsp->method()->has_exception_handlers()) {
176 return true;
177 }
178 }
179 return false;
180 }
181
182 //------------------------------save_ex_oop------------------------------------
183 // Save an exception without blowing stack contents or other JVM state.
184 void GraphKit::set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop) {
185 assert(!has_saved_ex_oop(ex_map), "clear ex-oop before setting again");
186 ex_map->add_req(ex_oop);
187 debug_only(verify_exception_state(ex_map));
188 }
189
190 inline static Node* common_saved_ex_oop(SafePointNode* ex_map, bool clear_it) {
191 assert(GraphKit::has_saved_ex_oop(ex_map), "ex_oop must be there");
192 Node* ex_oop = ex_map->in(ex_map->req()-1);
193 if (clear_it) ex_map->del_req(ex_map->req()-1);
194 return ex_oop;
195 }
196
197 //-----------------------------saved_ex_oop------------------------------------
198 // Recover a saved exception from its map.
199 Node* GraphKit::saved_ex_oop(SafePointNode* ex_map) {
200 return common_saved_ex_oop(ex_map, false);
201 }
202
203 //--------------------------clear_saved_ex_oop---------------------------------
204 // Erase a previously saved exception from its map.
205 Node* GraphKit::clear_saved_ex_oop(SafePointNode* ex_map) {
206 return common_saved_ex_oop(ex_map, true);
207 }
208
209 #ifdef ASSERT
210 //---------------------------has_saved_ex_oop----------------------------------
211 // Erase a previously saved exception from its map.
212 bool GraphKit::has_saved_ex_oop(SafePointNode* ex_map) {
213 return ex_map->req() == ex_map->jvms()->endoff()+1;
214 }
215 #endif
216
217 //-------------------------make_exception_state--------------------------------
218 // Turn the current JVM state into an exception state, appending the ex_oop.
219 SafePointNode* GraphKit::make_exception_state(Node* ex_oop) {
220 sync_jvms();
221 SafePointNode* ex_map = stop(); // do not manipulate this map any more
222 set_saved_ex_oop(ex_map, ex_oop);
223 return ex_map;
224 }
225
226
227 //--------------------------add_exception_state--------------------------------
228 // Add an exception to my list of exceptions.
229 void GraphKit::add_exception_state(SafePointNode* ex_map) {
230 if (ex_map == NULL || ex_map->control() == top()) {
231 return;
232 }
233 #ifdef ASSERT
234 verify_exception_state(ex_map);
235 if (has_exceptions()) {
236 assert(ex_map->jvms()->same_calls_as(_exceptions->jvms()), "all collected exceptions must come from the same place");
237 }
238 #endif
239
240 // If there is already an exception of exactly this type, merge with it.
241 // In particular, null-checks and other low-level exceptions common up here.
242 Node* ex_oop = saved_ex_oop(ex_map);
243 const Type* ex_type = _gvn.type(ex_oop);
244 if (ex_oop == top()) {
245 // No action needed.
246 return;
247 }
248 assert(ex_type->isa_instptr(), "exception must be an instance");
249 for (SafePointNode* e2 = _exceptions; e2 != NULL; e2 = e2->next_exception()) {
250 const Type* ex_type2 = _gvn.type(saved_ex_oop(e2));
251 // We check sp also because call bytecodes can generate exceptions
252 // both before and after arguments are popped!
253 if (ex_type2 == ex_type
254 && e2->_jvms->sp() == ex_map->_jvms->sp()) {
255 combine_exception_states(ex_map, e2);
256 return;
257 }
258 }
259
260 // No pre-existing exception of the same type. Chain it on the list.
261 push_exception_state(ex_map);
262 }
263
264 //-----------------------add_exception_states_from-----------------------------
265 void GraphKit::add_exception_states_from(JVMState* jvms) {
266 SafePointNode* ex_map = jvms->map()->next_exception();
267 if (ex_map != NULL) {
268 jvms->map()->set_next_exception(NULL);
269 for (SafePointNode* next_map; ex_map != NULL; ex_map = next_map) {
270 next_map = ex_map->next_exception();
271 ex_map->set_next_exception(NULL);
272 add_exception_state(ex_map);
273 }
274 }
275 }
276
277 //-----------------------transfer_exceptions_into_jvms-------------------------
278 JVMState* GraphKit::transfer_exceptions_into_jvms() {
279 if (map() == NULL) {
280 // We need a JVMS to carry the exceptions, but the map has gone away.
281 // Create a scratch JVMS, cloned from any of the exception states...
282 if (has_exceptions()) {
283 _map = _exceptions;
284 _map = clone_map();
285 _map->set_next_exception(NULL);
286 clear_saved_ex_oop(_map);
287 debug_only(verify_map());
288 } else {
289 // ...or created from scratch
290 JVMState* jvms = new (C) JVMState(_method, NULL);
291 jvms->set_bci(_bci);
292 jvms->set_sp(_sp);
293 jvms->set_map(new (C) SafePointNode(TypeFunc::Parms, jvms));
294 set_jvms(jvms);
295 for (uint i = 0; i < map()->req(); i++) map()->init_req(i, top());
296 set_all_memory(top());
297 while (map()->req() < jvms->endoff()) map()->add_req(top());
298 }
299 // (This is a kludge, in case you didn't notice.)
300 set_control(top());
301 }
302 JVMState* jvms = sync_jvms();
303 assert(!jvms->map()->has_exceptions(), "no exceptions on this map yet");
304 jvms->map()->set_next_exception(_exceptions);
305 _exceptions = NULL; // done with this set of exceptions
306 return jvms;
307 }
308
309 static inline void add_n_reqs(Node* dstphi, Node* srcphi) {
310 assert(is_hidden_merge(dstphi), "must be a special merge node");
311 assert(is_hidden_merge(srcphi), "must be a special merge node");
312 uint limit = srcphi->req();
313 for (uint i = PhiNode::Input; i < limit; i++) {
314 dstphi->add_req(srcphi->in(i));
315 }
316 }
317 static inline void add_one_req(Node* dstphi, Node* src) {
318 assert(is_hidden_merge(dstphi), "must be a special merge node");
319 assert(!is_hidden_merge(src), "must not be a special merge node");
320 dstphi->add_req(src);
321 }
322
323 //-----------------------combine_exception_states------------------------------
324 // This helper function combines exception states by building phis on a
325 // specially marked state-merging region. These regions and phis are
326 // untransformed, and can build up gradually. The region is marked by
327 // having a control input of its exception map, rather than NULL. Such
328 // regions do not appear except in this function, and in use_exception_state.
329 void GraphKit::combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map) {
330 if (failing()) return; // dying anyway...
331 JVMState* ex_jvms = ex_map->_jvms;
332 assert(ex_jvms->same_calls_as(phi_map->_jvms), "consistent call chains");
333 assert(ex_jvms->stkoff() == phi_map->_jvms->stkoff(), "matching locals");
334 assert(ex_jvms->sp() == phi_map->_jvms->sp(), "matching stack sizes");
335 assert(ex_jvms->monoff() == phi_map->_jvms->monoff(), "matching JVMS");
336 assert(ex_map->req() == phi_map->req(), "matching maps");
337 uint tos = ex_jvms->stkoff() + ex_jvms->sp();
338 Node* hidden_merge_mark = root();
339 Node* region = phi_map->control();
340 MergeMemNode* phi_mem = phi_map->merged_memory();
341 MergeMemNode* ex_mem = ex_map->merged_memory();
342 if (region->in(0) != hidden_merge_mark) {
343 // The control input is not (yet) a specially-marked region in phi_map.
344 // Make it so, and build some phis.
345 region = new (C) RegionNode(2);
346 _gvn.set_type(region, Type::CONTROL);
347 region->set_req(0, hidden_merge_mark); // marks an internal ex-state
348 region->init_req(1, phi_map->control());
349 phi_map->set_control(region);
350 Node* io_phi = PhiNode::make(region, phi_map->i_o(), Type::ABIO);
351 record_for_igvn(io_phi);
352 _gvn.set_type(io_phi, Type::ABIO);
353 phi_map->set_i_o(io_phi);
354 for (MergeMemStream mms(phi_mem); mms.next_non_empty(); ) {
355 Node* m = mms.memory();
356 Node* m_phi = PhiNode::make(region, m, Type::MEMORY, mms.adr_type(C));
357 record_for_igvn(m_phi);
358 _gvn.set_type(m_phi, Type::MEMORY);
359 mms.set_memory(m_phi);
360 }
361 }
362
363 // Either or both of phi_map and ex_map might already be converted into phis.
364 Node* ex_control = ex_map->control();
365 // if there is special marking on ex_map also, we add multiple edges from src
366 bool add_multiple = (ex_control->in(0) == hidden_merge_mark);
367 // how wide was the destination phi_map, originally?
368 uint orig_width = region->req();
369
370 if (add_multiple) {
371 add_n_reqs(region, ex_control);
372 add_n_reqs(phi_map->i_o(), ex_map->i_o());
373 } else {
374 // ex_map has no merges, so we just add single edges everywhere
375 add_one_req(region, ex_control);
376 add_one_req(phi_map->i_o(), ex_map->i_o());
377 }
378 for (MergeMemStream mms(phi_mem, ex_mem); mms.next_non_empty2(); ) {
379 if (mms.is_empty()) {
380 // get a copy of the base memory, and patch some inputs into it
381 const TypePtr* adr_type = mms.adr_type(C);
382 Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
383 assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
384 mms.set_memory(phi);
385 // Prepare to append interesting stuff onto the newly sliced phi:
386 while (phi->req() > orig_width) phi->del_req(phi->req()-1);
387 }
388 // Append stuff from ex_map:
389 if (add_multiple) {
390 add_n_reqs(mms.memory(), mms.memory2());
391 } else {
392 add_one_req(mms.memory(), mms.memory2());
393 }
394 }
395 uint limit = ex_map->req();
396 for (uint i = TypeFunc::Parms; i < limit; i++) {
397 // Skip everything in the JVMS after tos. (The ex_oop follows.)
398 if (i == tos) i = ex_jvms->monoff();
399 Node* src = ex_map->in(i);
400 Node* dst = phi_map->in(i);
401 if (src != dst) {
402 PhiNode* phi;
403 if (dst->in(0) != region) {
404 dst = phi = PhiNode::make(region, dst, _gvn.type(dst));
405 record_for_igvn(phi);
406 _gvn.set_type(phi, phi->type());
407 phi_map->set_req(i, dst);
408 // Prepare to append interesting stuff onto the new phi:
409 while (dst->req() > orig_width) dst->del_req(dst->req()-1);
410 } else {
411 assert(dst->is_Phi(), "nobody else uses a hidden region");
412 phi = (PhiNode*)dst;
413 }
414 if (add_multiple && src->in(0) == ex_control) {
415 // Both are phis.
416 add_n_reqs(dst, src);
417 } else {
418 while (dst->req() < region->req()) add_one_req(dst, src);
419 }
420 const Type* srctype = _gvn.type(src);
421 if (phi->type() != srctype) {
422 const Type* dsttype = phi->type()->meet(srctype);
423 if (phi->type() != dsttype) {
424 phi->set_type(dsttype);
425 _gvn.set_type(phi, dsttype);
426 }
427 }
428 }
429 }
430 }
431
432 //--------------------------use_exception_state--------------------------------
433 Node* GraphKit::use_exception_state(SafePointNode* phi_map) {
434 if (failing()) { stop(); return top(); }
435 Node* region = phi_map->control();
436 Node* hidden_merge_mark = root();
437 assert(phi_map->jvms()->map() == phi_map, "sanity: 1-1 relation");
438 Node* ex_oop = clear_saved_ex_oop(phi_map);
439 if (region->in(0) == hidden_merge_mark) {
440 // Special marking for internal ex-states. Process the phis now.
441 region->set_req(0, region); // now it's an ordinary region
442 set_jvms(phi_map->jvms()); // ...so now we can use it as a map
443 // Note: Setting the jvms also sets the bci and sp.
444 set_control(_gvn.transform(region));
445 uint tos = jvms()->stkoff() + sp();
446 for (uint i = 1; i < tos; i++) {
447 Node* x = phi_map->in(i);
448 if (x->in(0) == region) {
449 assert(x->is_Phi(), "expected a special phi");
450 phi_map->set_req(i, _gvn.transform(x));
451 }
452 }
453 for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
454 Node* x = mms.memory();
455 if (x->in(0) == region) {
456 assert(x->is_Phi(), "nobody else uses a hidden region");
457 mms.set_memory(_gvn.transform(x));
458 }
459 }
460 if (ex_oop->in(0) == region) {
461 assert(ex_oop->is_Phi(), "expected a special phi");
462 ex_oop = _gvn.transform(ex_oop);
463 }
464 } else {
465 set_jvms(phi_map->jvms());
466 }
467
468 assert(!is_hidden_merge(phi_map->control()), "hidden ex. states cleared");
469 assert(!is_hidden_merge(phi_map->i_o()), "hidden ex. states cleared");
470 return ex_oop;
471 }
472
473 //---------------------------------java_bc-------------------------------------
474 Bytecodes::Code GraphKit::java_bc() const {
475 ciMethod* method = this->method();
476 int bci = this->bci();
477 if (method != NULL && bci != InvocationEntryBci)
478 return method->java_code_at_bci(bci);
479 else
480 return Bytecodes::_illegal;
481 }
482
483 void GraphKit::uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
484 bool must_throw) {
485 // if the exception capability is set, then we will generate code
486 // to check the JavaThread.should_post_on_exceptions flag to see
487 // if we actually need to report exception events (for this
488 // thread). If we don't need to report exception events, we will
489 // take the normal fast path provided by add_exception_events. If
490 // exception event reporting is enabled for this thread, we will
491 // take the uncommon_trap in the BuildCutout below.
492
493 // first must access the should_post_on_exceptions_flag in this thread's JavaThread
494 Node* jthread = _gvn.transform(new (C) ThreadLocalNode());
495 Node* adr = basic_plus_adr(top(), jthread, in_bytes(JavaThread::should_post_on_exceptions_flag_offset()));
496 Node* should_post_flag = make_load(control(), adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw, false);
497
498 // Test the should_post_on_exceptions_flag vs. 0
499 Node* chk = _gvn.transform( new (C) CmpINode(should_post_flag, intcon(0)) );
500 Node* tst = _gvn.transform( new (C) BoolNode(chk, BoolTest::eq) );
501
502 // Branch to slow_path if should_post_on_exceptions_flag was true
503 { BuildCutout unless(this, tst, PROB_MAX);
504 // Do not try anything fancy if we're notifying the VM on every throw.
505 // Cf. case Bytecodes::_athrow in parse2.cpp.
506 uncommon_trap(reason, Deoptimization::Action_none,
507 (ciKlass*)NULL, (char*)NULL, must_throw);
508 }
509
510 }
511
512 //------------------------------builtin_throw----------------------------------
513 void GraphKit::builtin_throw(Deoptimization::DeoptReason reason, Node* arg) {
514 bool must_throw = true;
515
516 if (env()->jvmti_can_post_on_exceptions()) {
517 // check if we must post exception events, take uncommon trap if so
518 uncommon_trap_if_should_post_on_exceptions(reason, must_throw);
519 // here if should_post_on_exceptions is false
520 // continue on with the normal codegen
521 }
522
523 // If this particular condition has not yet happened at this
524 // bytecode, then use the uncommon trap mechanism, and allow for
525 // a future recompilation if several traps occur here.
526 // If the throw is hot, try to use a more complicated inline mechanism
527 // which keeps execution inside the compiled code.
528 bool treat_throw_as_hot = false;
529 ciMethodData* md = method()->method_data();
530
531 if (ProfileTraps) {
532 if (too_many_traps(reason)) {
533 treat_throw_as_hot = true;
534 }
535 // (If there is no MDO at all, assume it is early in
536 // execution, and that any deopts are part of the
537 // startup transient, and don't need to be remembered.)
538
539 // Also, if there is a local exception handler, treat all throws
540 // as hot if there has been at least one in this method.
541 if (C->trap_count(reason) != 0
542 && method()->method_data()->trap_count(reason) != 0
543 && has_ex_handler()) {
544 treat_throw_as_hot = true;
545 }
546 }
547
548 // If this throw happens frequently, an uncommon trap might cause
549 // a performance pothole. If there is a local exception handler,
550 // and if this particular bytecode appears to be deoptimizing often,
551 // let us handle the throw inline, with a preconstructed instance.
552 // Note: If the deopt count has blown up, the uncommon trap
553 // runtime is going to flush this nmethod, not matter what.
554 if (treat_throw_as_hot
555 && (!StackTraceInThrowable || OmitStackTraceInFastThrow)) {
556 // If the throw is local, we use a pre-existing instance and
557 // punt on the backtrace. This would lead to a missing backtrace
558 // (a repeat of 4292742) if the backtrace object is ever asked
559 // for its backtrace.
560 // Fixing this remaining case of 4292742 requires some flavor of
561 // escape analysis. Leave that for the future.
562 ciInstance* ex_obj = NULL;
563 switch (reason) {
564 case Deoptimization::Reason_null_check:
565 ex_obj = env()->NullPointerException_instance();
566 break;
567 case Deoptimization::Reason_div0_check:
568 ex_obj = env()->ArithmeticException_instance();
569 break;
570 case Deoptimization::Reason_range_check:
571 ex_obj = env()->ArrayIndexOutOfBoundsException_instance();
572 break;
573 case Deoptimization::Reason_class_check:
574 if (java_bc() == Bytecodes::_aastore) {
575 ex_obj = env()->ArrayStoreException_instance();
576 } else {
577 ex_obj = env()->ClassCastException_instance();
578 }
579 break;
580 }
581 if (failing()) { stop(); return; } // exception allocation might fail
582 if (ex_obj != NULL) {
583 // Cheat with a preallocated exception object.
584 if (C->log() != NULL)
585 C->log()->elem("hot_throw preallocated='1' reason='%s'",
586 Deoptimization::trap_reason_name(reason));
587 const TypeInstPtr* ex_con = TypeInstPtr::make(ex_obj);
588 Node* ex_node = _gvn.transform( ConNode::make(C, ex_con) );
589
590 // Clear the detail message of the preallocated exception object.
591 // Weblogic sometimes mutates the detail message of exceptions
592 // using reflection.
593 int offset = java_lang_Throwable::get_detailMessage_offset();
594 const TypePtr* adr_typ = ex_con->add_offset(offset);
595
596 Node *adr = basic_plus_adr(ex_node, ex_node, offset);
597 const TypeOopPtr* val_type = TypeOopPtr::make_from_klass(env()->String_klass());
598 Node *store = store_oop_to_object(control(), ex_node, adr, adr_typ, null(), val_type, T_OBJECT);
599
600 add_exception_state(make_exception_state(ex_node));
601 return;
602 }
603 }
604
605 // %%% Maybe add entry to OptoRuntime which directly throws the exc.?
606 // It won't be much cheaper than bailing to the interp., since we'll
607 // have to pass up all the debug-info, and the runtime will have to
608 // create the stack trace.
609
610 // Usual case: Bail to interpreter.
611 // Reserve the right to recompile if we haven't seen anything yet.
612
613 Deoptimization::DeoptAction action = Deoptimization::Action_maybe_recompile;
614 if (treat_throw_as_hot
615 && (method()->method_data()->trap_recompiled_at(bci())
616 || C->too_many_traps(reason))) {
617 // We cannot afford to take more traps here. Suffer in the interpreter.
618 if (C->log() != NULL)
619 C->log()->elem("hot_throw preallocated='0' reason='%s' mcount='%d'",
620 Deoptimization::trap_reason_name(reason),
621 C->trap_count(reason));
622 action = Deoptimization::Action_none;
623 }
624
625 // "must_throw" prunes the JVM state to include only the stack, if there
626 // are no local exception handlers. This should cut down on register
627 // allocation time and code size, by drastically reducing the number
628 // of in-edges on the call to the uncommon trap.
629
630 uncommon_trap(reason, action, (ciKlass*)NULL, (char*)NULL, must_throw);
631 }
632
633
634 //----------------------------PreserveJVMState---------------------------------
635 PreserveJVMState::PreserveJVMState(GraphKit* kit, bool clone_map) {
636 debug_only(kit->verify_map());
637 _kit = kit;
638 _map = kit->map(); // preserve the map
639 _sp = kit->sp();
640 kit->set_map(clone_map ? kit->clone_map() : NULL);
641 #ifdef ASSERT
642 _bci = kit->bci();
643 Parse* parser = kit->is_Parse();
644 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
645 _block = block;
646 #endif
647 }
648 PreserveJVMState::~PreserveJVMState() {
649 GraphKit* kit = _kit;
650 #ifdef ASSERT
651 assert(kit->bci() == _bci, "bci must not shift");
652 Parse* parser = kit->is_Parse();
653 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
654 assert(block == _block, "block must not shift");
655 #endif
656 kit->set_map(_map);
657 kit->set_sp(_sp);
658 }
659
660
661 //-----------------------------BuildCutout-------------------------------------
662 BuildCutout::BuildCutout(GraphKit* kit, Node* p, float prob, float cnt)
663 : PreserveJVMState(kit)
664 {
665 assert(p->is_Con() || p->is_Bool(), "test must be a bool");
666 SafePointNode* outer_map = _map; // preserved map is caller's
667 SafePointNode* inner_map = kit->map();
668 IfNode* iff = kit->create_and_map_if(outer_map->control(), p, prob, cnt);
669 outer_map->set_control(kit->gvn().transform( new (kit->C) IfTrueNode(iff) ));
670 inner_map->set_control(kit->gvn().transform( new (kit->C) IfFalseNode(iff) ));
671 }
672 BuildCutout::~BuildCutout() {
673 GraphKit* kit = _kit;
674 assert(kit->stopped(), "cutout code must stop, throw, return, etc.");
675 }
676
677 //---------------------------PreserveReexecuteState----------------------------
678 PreserveReexecuteState::PreserveReexecuteState(GraphKit* kit) {
679 assert(!kit->stopped(), "must call stopped() before");
680 _kit = kit;
681 _sp = kit->sp();
682 _reexecute = kit->jvms()->_reexecute;
683 }
684 PreserveReexecuteState::~PreserveReexecuteState() {
685 if (_kit->stopped()) return;
686 _kit->jvms()->_reexecute = _reexecute;
687 _kit->set_sp(_sp);
688 }
689
690 //------------------------------clone_map--------------------------------------
691 // Implementation of PreserveJVMState
692 //
693 // Only clone_map(...) here. If this function is only used in the
694 // PreserveJVMState class we may want to get rid of this extra
695 // function eventually and do it all there.
696
697 SafePointNode* GraphKit::clone_map() {
698 if (map() == NULL) return NULL;
699
700 // Clone the memory edge first
701 Node* mem = MergeMemNode::make(C, map()->memory());
702 gvn().set_type_bottom(mem);
703
704 SafePointNode *clonemap = (SafePointNode*)map()->clone();
705 JVMState* jvms = this->jvms();
706 JVMState* clonejvms = jvms->clone_shallow(C);
707 clonemap->set_memory(mem);
708 clonemap->set_jvms(clonejvms);
709 clonejvms->set_map(clonemap);
710 record_for_igvn(clonemap);
711 gvn().set_type_bottom(clonemap);
712 return clonemap;
713 }
714
715
716 //-----------------------------set_map_clone-----------------------------------
717 void GraphKit::set_map_clone(SafePointNode* m) {
718 _map = m;
719 _map = clone_map();
720 _map->set_next_exception(NULL);
721 debug_only(verify_map());
722 }
723
724
725 //----------------------------kill_dead_locals---------------------------------
726 // Detect any locals which are known to be dead, and force them to top.
727 void GraphKit::kill_dead_locals() {
728 // Consult the liveness information for the locals. If any
729 // of them are unused, then they can be replaced by top(). This
730 // should help register allocation time and cut down on the size
731 // of the deoptimization information.
732
733 // This call is made from many of the bytecode handling
734 // subroutines called from the Big Switch in do_one_bytecode.
735 // Every bytecode which might include a slow path is responsible
736 // for killing its dead locals. The more consistent we
737 // are about killing deads, the fewer useless phis will be
738 // constructed for them at various merge points.
739
740 // bci can be -1 (InvocationEntryBci). We return the entry
741 // liveness for the method.
742
743 if (method() == NULL || method()->code_size() == 0) {
744 // We are building a graph for a call to a native method.
745 // All locals are live.
746 return;
747 }
748
749 ResourceMark rm;
750
751 // Consult the liveness information for the locals. If any
752 // of them are unused, then they can be replaced by top(). This
753 // should help register allocation time and cut down on the size
754 // of the deoptimization information.
755 MethodLivenessResult live_locals = method()->liveness_at_bci(bci());
756
757 int len = (int)live_locals.size();
758 assert(len <= jvms()->loc_size(), "too many live locals");
759 for (int local = 0; local < len; local++) {
760 if (!live_locals.at(local)) {
761 set_local(local, top());
762 }
763 }
764 }
765
766 #ifdef ASSERT
767 //-------------------------dead_locals_are_killed------------------------------
768 // Return true if all dead locals are set to top in the map.
769 // Used to assert "clean" debug info at various points.
770 bool GraphKit::dead_locals_are_killed() {
771 if (method() == NULL || method()->code_size() == 0) {
772 // No locals need to be dead, so all is as it should be.
773 return true;
774 }
775
776 // Make sure somebody called kill_dead_locals upstream.
777 ResourceMark rm;
778 for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
779 if (jvms->loc_size() == 0) continue; // no locals to consult
780 SafePointNode* map = jvms->map();
781 ciMethod* method = jvms->method();
782 int bci = jvms->bci();
783 if (jvms == this->jvms()) {
784 bci = this->bci(); // it might not yet be synched
785 }
786 MethodLivenessResult live_locals = method->liveness_at_bci(bci);
787 int len = (int)live_locals.size();
788 if (!live_locals.is_valid() || len == 0)
789 // This method is trivial, or is poisoned by a breakpoint.
790 return true;
791 assert(len == jvms->loc_size(), "live map consistent with locals map");
792 for (int local = 0; local < len; local++) {
793 if (!live_locals.at(local) && map->local(jvms, local) != top()) {
794 if (PrintMiscellaneous && (Verbose || WizardMode)) {
795 tty->print_cr("Zombie local %d: ", local);
796 jvms->dump();
797 }
798 return false;
799 }
800 }
801 }
802 return true;
803 }
804
805 #endif //ASSERT
806
807 // Helper function for enforcing certain bytecodes to reexecute if
808 // deoptimization happens
809 static bool should_reexecute_implied_by_bytecode(JVMState *jvms, bool is_anewarray) {
810 ciMethod* cur_method = jvms->method();
811 int cur_bci = jvms->bci();
812 if (cur_method != NULL && cur_bci != InvocationEntryBci) {
813 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci);
814 return Interpreter::bytecode_should_reexecute(code) ||
815 is_anewarray && code == Bytecodes::_multianewarray;
816 // Reexecute _multianewarray bytecode which was replaced with
817 // sequence of [a]newarray. See Parse::do_multianewarray().
818 //
819 // Note: interpreter should not have it set since this optimization
820 // is limited by dimensions and guarded by flag so in some cases
821 // multianewarray() runtime calls will be generated and
822 // the bytecode should not be reexecutes (stack will not be reset).
823 } else
824 return false;
825 }
826
827 // Helper function for adding JVMState and debug information to node
828 void GraphKit::add_safepoint_edges(SafePointNode* call, bool must_throw) {
829 // Add the safepoint edges to the call (or other safepoint).
830
831 // Make sure dead locals are set to top. This
832 // should help register allocation time and cut down on the size
833 // of the deoptimization information.
834 assert(dead_locals_are_killed(), "garbage in debug info before safepoint");
835
836 // Walk the inline list to fill in the correct set of JVMState's
837 // Also fill in the associated edges for each JVMState.
838
839 // If the bytecode needs to be reexecuted we need to put
840 // the arguments back on the stack.
841 const bool should_reexecute = jvms()->should_reexecute();
842 JVMState* youngest_jvms = should_reexecute ? sync_jvms_for_reexecute() : sync_jvms();
843
844 // NOTE: set_bci (called from sync_jvms) might reset the reexecute bit to
845 // undefined if the bci is different. This is normal for Parse but it
846 // should not happen for LibraryCallKit because only one bci is processed.
847 assert(!is_LibraryCallKit() || (jvms()->should_reexecute() == should_reexecute),
848 "in LibraryCallKit the reexecute bit should not change");
849
850 // If we are guaranteed to throw, we can prune everything but the
851 // input to the current bytecode.
852 bool can_prune_locals = false;
853 uint stack_slots_not_pruned = 0;
854 int inputs = 0, depth = 0;
855 if (must_throw) {
856 assert(method() == youngest_jvms->method(), "sanity");
857 if (compute_stack_effects(inputs, depth)) {
858 can_prune_locals = true;
859 stack_slots_not_pruned = inputs;
860 }
861 }
862
863 if (env()->jvmti_can_access_local_variables()) {
864 // At any safepoint, this method can get breakpointed, which would
865 // then require an immediate deoptimization.
866 can_prune_locals = false; // do not prune locals
867 stack_slots_not_pruned = 0;
868 }
869
870 // do not scribble on the input jvms
871 JVMState* out_jvms = youngest_jvms->clone_deep(C);
872 call->set_jvms(out_jvms); // Start jvms list for call node
873
874 // For a known set of bytecodes, the interpreter should reexecute them if
875 // deoptimization happens. We set the reexecute state for them here
876 if (out_jvms->is_reexecute_undefined() && //don't change if already specified
877 should_reexecute_implied_by_bytecode(out_jvms, call->is_AllocateArray())) {
878 out_jvms->set_should_reexecute(true); //NOTE: youngest_jvms not changed
879 }
880
881 // Presize the call:
882 DEBUG_ONLY(uint non_debug_edges = call->req());
883 call->add_req_batch(top(), youngest_jvms->debug_depth());
884 assert(call->req() == non_debug_edges + youngest_jvms->debug_depth(), "");
885
886 // Set up edges so that the call looks like this:
887 // Call [state:] ctl io mem fptr retadr
888 // [parms:] parm0 ... parmN
889 // [root:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
890 // [...mid:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN [...]
891 // [young:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
892 // Note that caller debug info precedes callee debug info.
893
894 // Fill pointer walks backwards from "young:" to "root:" in the diagram above:
895 uint debug_ptr = call->req();
896
897 // Loop over the map input edges associated with jvms, add them
898 // to the call node, & reset all offsets to match call node array.
899 for (JVMState* in_jvms = youngest_jvms; in_jvms != NULL; ) {
900 uint debug_end = debug_ptr;
901 uint debug_start = debug_ptr - in_jvms->debug_size();
902 debug_ptr = debug_start; // back up the ptr
903
904 uint p = debug_start; // walks forward in [debug_start, debug_end)
905 uint j, k, l;
906 SafePointNode* in_map = in_jvms->map();
907 out_jvms->set_map(call);
908
909 if (can_prune_locals) {
910 assert(in_jvms->method() == out_jvms->method(), "sanity");
911 // If the current throw can reach an exception handler in this JVMS,
912 // then we must keep everything live that can reach that handler.
913 // As a quick and dirty approximation, we look for any handlers at all.
914 if (in_jvms->method()->has_exception_handlers()) {
915 can_prune_locals = false;
916 }
917 }
918
919 // Add the Locals
920 k = in_jvms->locoff();
921 l = in_jvms->loc_size();
922 out_jvms->set_locoff(p);
923 if (!can_prune_locals) {
924 for (j = 0; j < l; j++)
925 call->set_req(p++, in_map->in(k+j));
926 } else {
927 p += l; // already set to top above by add_req_batch
928 }
929
930 // Add the Expression Stack
931 k = in_jvms->stkoff();
932 l = in_jvms->sp();
933 out_jvms->set_stkoff(p);
934 if (!can_prune_locals) {
935 for (j = 0; j < l; j++)
936 call->set_req(p++, in_map->in(k+j));
937 } else if (can_prune_locals && stack_slots_not_pruned != 0) {
938 // Divide stack into {S0,...,S1}, where S0 is set to top.
939 uint s1 = stack_slots_not_pruned;
940 stack_slots_not_pruned = 0; // for next iteration
941 if (s1 > l) s1 = l;
942 uint s0 = l - s1;
943 p += s0; // skip the tops preinstalled by add_req_batch
944 for (j = s0; j < l; j++)
945 call->set_req(p++, in_map->in(k+j));
946 } else {
947 p += l; // already set to top above by add_req_batch
948 }
949
950 // Add the Monitors
951 k = in_jvms->monoff();
952 l = in_jvms->mon_size();
953 out_jvms->set_monoff(p);
954 for (j = 0; j < l; j++)
955 call->set_req(p++, in_map->in(k+j));
956
957 // Copy any scalar object fields.
958 k = in_jvms->scloff();
959 l = in_jvms->scl_size();
960 out_jvms->set_scloff(p);
961 for (j = 0; j < l; j++)
962 call->set_req(p++, in_map->in(k+j));
963
964 // Finish the new jvms.
965 out_jvms->set_endoff(p);
966
967 assert(out_jvms->endoff() == debug_end, "fill ptr must match");
968 assert(out_jvms->depth() == in_jvms->depth(), "depth must match");
969 assert(out_jvms->loc_size() == in_jvms->loc_size(), "size must match");
970 assert(out_jvms->mon_size() == in_jvms->mon_size(), "size must match");
971 assert(out_jvms->scl_size() == in_jvms->scl_size(), "size must match");
972 assert(out_jvms->debug_size() == in_jvms->debug_size(), "size must match");
973
974 // Update the two tail pointers in parallel.
975 out_jvms = out_jvms->caller();
976 in_jvms = in_jvms->caller();
977 }
978
979 assert(debug_ptr == non_debug_edges, "debug info must fit exactly");
980
981 // Test the correctness of JVMState::debug_xxx accessors:
982 assert(call->jvms()->debug_start() == non_debug_edges, "");
983 assert(call->jvms()->debug_end() == call->req(), "");
984 assert(call->jvms()->debug_depth() == call->req() - non_debug_edges, "");
985 }
986
987 bool GraphKit::compute_stack_effects(int& inputs, int& depth) {
988 Bytecodes::Code code = java_bc();
989 if (code == Bytecodes::_wide) {
990 code = method()->java_code_at_bci(bci() + 1);
991 }
992
993 BasicType rtype = T_ILLEGAL;
994 int rsize = 0;
995
996 if (code != Bytecodes::_illegal) {
997 depth = Bytecodes::depth(code); // checkcast=0, athrow=-1
998 rtype = Bytecodes::result_type(code); // checkcast=P, athrow=V
999 if (rtype < T_CONFLICT)
1000 rsize = type2size[rtype];
1001 }
1002
1003 switch (code) {
1004 case Bytecodes::_illegal:
1005 return false;
1006
1007 case Bytecodes::_ldc:
1008 case Bytecodes::_ldc_w:
1009 case Bytecodes::_ldc2_w:
1010 inputs = 0;
1011 break;
1012
1013 case Bytecodes::_dup: inputs = 1; break;
1014 case Bytecodes::_dup_x1: inputs = 2; break;
1015 case Bytecodes::_dup_x2: inputs = 3; break;
1016 case Bytecodes::_dup2: inputs = 2; break;
1017 case Bytecodes::_dup2_x1: inputs = 3; break;
1018 case Bytecodes::_dup2_x2: inputs = 4; break;
1019 case Bytecodes::_swap: inputs = 2; break;
1020 case Bytecodes::_arraylength: inputs = 1; break;
1021
1022 case Bytecodes::_getstatic:
1023 case Bytecodes::_putstatic:
1024 case Bytecodes::_getfield:
1025 case Bytecodes::_putfield:
1026 {
1027 bool ignored_will_link;
1028 ciField* field = method()->get_field_at_bci(bci(), ignored_will_link);
1029 int size = field->type()->size();
1030 bool is_get = (depth >= 0), is_static = (depth & 1);
1031 inputs = (is_static ? 0 : 1);
1032 if (is_get) {
1033 depth = size - inputs;
1034 } else {
1035 inputs += size; // putxxx pops the value from the stack
1036 depth = - inputs;
1037 }
1038 }
1039 break;
1040
1041 case Bytecodes::_invokevirtual:
1042 case Bytecodes::_invokespecial:
1043 case Bytecodes::_invokestatic:
1044 case Bytecodes::_invokedynamic:
1045 case Bytecodes::_invokeinterface:
1046 {
1047 bool ignored_will_link;
1048 ciSignature* declared_signature = NULL;
1049 ciMethod* ignored_callee = method()->get_method_at_bci(bci(), ignored_will_link, &declared_signature);
1050 assert(declared_signature != NULL, "cannot be null");
1051 inputs = declared_signature->arg_size_for_bc(code);
1052 int size = declared_signature->return_type()->size();
1053 depth = size - inputs;
1054 }
1055 break;
1056
1057 case Bytecodes::_multianewarray:
1058 {
1059 ciBytecodeStream iter(method());
1060 iter.reset_to_bci(bci());
1061 iter.next();
1062 inputs = iter.get_dimensions();
1063 assert(rsize == 1, "");
1064 depth = rsize - inputs;
1065 }
1066 break;
1067
1068 case Bytecodes::_ireturn:
1069 case Bytecodes::_lreturn:
1070 case Bytecodes::_freturn:
1071 case Bytecodes::_dreturn:
1072 case Bytecodes::_areturn:
1073 assert(rsize = -depth, "");
1074 inputs = rsize;
1075 break;
1076
1077 case Bytecodes::_jsr:
1078 case Bytecodes::_jsr_w:
1079 inputs = 0;
1080 depth = 1; // S.B. depth=1, not zero
1081 break;
1082
1083 default:
1084 // bytecode produces a typed result
1085 inputs = rsize - depth;
1086 assert(inputs >= 0, "");
1087 break;
1088 }
1089
1090 #ifdef ASSERT
1091 // spot check
1092 int outputs = depth + inputs;
1093 assert(outputs >= 0, "sanity");
1094 switch (code) {
1095 case Bytecodes::_checkcast: assert(inputs == 1 && outputs == 1, ""); break;
1096 case Bytecodes::_athrow: assert(inputs == 1 && outputs == 0, ""); break;
1097 case Bytecodes::_aload_0: assert(inputs == 0 && outputs == 1, ""); break;
1098 case Bytecodes::_return: assert(inputs == 0 && outputs == 0, ""); break;
1099 case Bytecodes::_drem: assert(inputs == 4 && outputs == 2, ""); break;
1100 }
1101 #endif //ASSERT
1102
1103 return true;
1104 }
1105
1106
1107
1108 //------------------------------basic_plus_adr---------------------------------
1109 Node* GraphKit::basic_plus_adr(Node* base, Node* ptr, Node* offset) {
1110 // short-circuit a common case
1111 if (offset == intcon(0)) return ptr;
1112 return _gvn.transform( new (C) AddPNode(base, ptr, offset) );
1113 }
1114
1115 Node* GraphKit::ConvI2L(Node* offset) {
1116 // short-circuit a common case
1117 jint offset_con = find_int_con(offset, Type::OffsetBot);
1118 if (offset_con != Type::OffsetBot) {
1119 return longcon((jlong) offset_con);
1120 }
1121 return _gvn.transform( new (C) ConvI2LNode(offset));
1122 }
1123 Node* GraphKit::ConvL2I(Node* offset) {
1124 // short-circuit a common case
1125 jlong offset_con = find_long_con(offset, (jlong)Type::OffsetBot);
1126 if (offset_con != (jlong)Type::OffsetBot) {
1127 return intcon((int) offset_con);
1128 }
1129 return _gvn.transform( new (C) ConvL2INode(offset));
1130 }
1131
1132 //-------------------------load_object_klass-----------------------------------
1133 Node* GraphKit::load_object_klass(Node* obj) {
1134 // Special-case a fresh allocation to avoid building nodes:
1135 Node* akls = AllocateNode::Ideal_klass(obj, &_gvn);
1136 if (akls != NULL) return akls;
1137 Node* k_adr = basic_plus_adr(obj, oopDesc::klass_offset_in_bytes());
1138 return _gvn.transform( LoadKlassNode::make(_gvn, immutable_memory(), k_adr, TypeInstPtr::KLASS) );
1139 }
1140
1141 //-------------------------load_array_length-----------------------------------
1142 Node* GraphKit::load_array_length(Node* array) {
1143 // Special-case a fresh allocation to avoid building nodes:
1144 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(array, &_gvn);
1145 Node *alen;
1146 if (alloc == NULL) {
1147 Node *r_adr = basic_plus_adr(array, arrayOopDesc::length_offset_in_bytes());
1148 alen = _gvn.transform( new (C) LoadRangeNode(0, immutable_memory(), r_adr, TypeInt::POS));
1149 } else {
1150 alen = alloc->Ideal_length();
1151 Node* ccast = alloc->make_ideal_length(_gvn.type(array)->is_oopptr(), &_gvn);
1152 if (ccast != alen) {
1153 alen = _gvn.transform(ccast);
1154 }
1155 }
1156 return alen;
1157 }
1158
1159 //------------------------------do_null_check----------------------------------
1160 // Helper function to do a NULL pointer check. Returned value is
1161 // the incoming address with NULL casted away. You are allowed to use the
1162 // not-null value only if you are control dependent on the test.
1163 extern int explicit_null_checks_inserted,
1164 explicit_null_checks_elided;
1165 Node* GraphKit::null_check_common(Node* value, BasicType type,
1166 // optional arguments for variations:
1167 bool assert_null,
1168 Node* *null_control) {
1169 assert(!assert_null || null_control == NULL, "not both at once");
1170 if (stopped()) return top();
1171 if (!GenerateCompilerNullChecks && !assert_null && null_control == NULL) {
1172 // For some performance testing, we may wish to suppress null checking.
1173 value = cast_not_null(value); // Make it appear to be non-null (4962416).
1174 return value;
1175 }
1176 explicit_null_checks_inserted++;
1177
1178 // Construct NULL check
1179 Node *chk = NULL;
1180 switch(type) {
1181 case T_LONG : chk = new (C) CmpLNode(value, _gvn.zerocon(T_LONG)); break;
1182 case T_INT : chk = new (C) CmpINode(value, _gvn.intcon(0)); break;
1183 case T_ARRAY : // fall through
1184 type = T_OBJECT; // simplify further tests
1185 case T_OBJECT : {
1186 const Type *t = _gvn.type( value );
1187
1188 const TypeOopPtr* tp = t->isa_oopptr();
1189 if (tp != NULL && tp->klass() != NULL && !tp->klass()->is_loaded()
1190 // Only for do_null_check, not any of its siblings:
1191 && !assert_null && null_control == NULL) {
1192 // Usually, any field access or invocation on an unloaded oop type
1193 // will simply fail to link, since the statically linked class is
1194 // likely also to be unloaded. However, in -Xcomp mode, sometimes
1195 // the static class is loaded but the sharper oop type is not.
1196 // Rather than checking for this obscure case in lots of places,
1197 // we simply observe that a null check on an unloaded class
1198 // will always be followed by a nonsense operation, so we
1199 // can just issue the uncommon trap here.
1200 // Our access to the unloaded class will only be correct
1201 // after it has been loaded and initialized, which requires
1202 // a trip through the interpreter.
1203 #ifndef PRODUCT
1204 if (WizardMode) { tty->print("Null check of unloaded "); tp->klass()->print(); tty->cr(); }
1205 #endif
1206 uncommon_trap(Deoptimization::Reason_unloaded,
1207 Deoptimization::Action_reinterpret,
1208 tp->klass(), "!loaded");
1209 return top();
1210 }
1211
1212 if (assert_null) {
1213 // See if the type is contained in NULL_PTR.
1214 // If so, then the value is already null.
1215 if (t->higher_equal(TypePtr::NULL_PTR)) {
1216 explicit_null_checks_elided++;
1217 return value; // Elided null assert quickly!
1218 }
1219 } else {
1220 // See if mixing in the NULL pointer changes type.
1221 // If so, then the NULL pointer was not allowed in the original
1222 // type. In other words, "value" was not-null.
1223 if (t->meet(TypePtr::NULL_PTR) != t) {
1224 // same as: if (!TypePtr::NULL_PTR->higher_equal(t)) ...
1225 explicit_null_checks_elided++;
1226 return value; // Elided null check quickly!
1227 }
1228 }
1229 chk = new (C) CmpPNode( value, null() );
1230 break;
1231 }
1232
1233 default:
1234 fatal(err_msg_res("unexpected type: %s", type2name(type)));
1235 }
1236 assert(chk != NULL, "sanity check");
1237 chk = _gvn.transform(chk);
1238
1239 BoolTest::mask btest = assert_null ? BoolTest::eq : BoolTest::ne;
1240 BoolNode *btst = new (C) BoolNode( chk, btest);
1241 Node *tst = _gvn.transform( btst );
1242
1243 //-----------
1244 // if peephole optimizations occurred, a prior test existed.
1245 // If a prior test existed, maybe it dominates as we can avoid this test.
1246 if (tst != btst && type == T_OBJECT) {
1247 // At this point we want to scan up the CFG to see if we can
1248 // find an identical test (and so avoid this test altogether).
1249 Node *cfg = control();
1250 int depth = 0;
1251 while( depth < 16 ) { // Limit search depth for speed
1252 if( cfg->Opcode() == Op_IfTrue &&
1253 cfg->in(0)->in(1) == tst ) {
1254 // Found prior test. Use "cast_not_null" to construct an identical
1255 // CastPP (and hence hash to) as already exists for the prior test.
1256 // Return that casted value.
1257 if (assert_null) {
1258 replace_in_map(value, null());
1259 return null(); // do not issue the redundant test
1260 }
1261 Node *oldcontrol = control();
1262 set_control(cfg);
1263 Node *res = cast_not_null(value);
1264 set_control(oldcontrol);
1265 explicit_null_checks_elided++;
1266 return res;
1267 }
1268 cfg = IfNode::up_one_dom(cfg, /*linear_only=*/ true);
1269 if (cfg == NULL) break; // Quit at region nodes
1270 depth++;
1271 }
1272 }
1273
1274 //-----------
1275 // Branch to failure if null
1276 float ok_prob = PROB_MAX; // a priori estimate: nulls never happen
1277 Deoptimization::DeoptReason reason;
1278 if (assert_null)
1279 reason = Deoptimization::Reason_null_assert;
1280 else if (type == T_OBJECT)
1281 reason = Deoptimization::Reason_null_check;
1282 else
1283 reason = Deoptimization::Reason_div0_check;
1284
1285 // %%% Since Reason_unhandled is not recorded on a per-bytecode basis,
1286 // ciMethodData::has_trap_at will return a conservative -1 if any
1287 // must-be-null assertion has failed. This could cause performance
1288 // problems for a method after its first do_null_assert failure.
1289 // Consider using 'Reason_class_check' instead?
1290
1291 // To cause an implicit null check, we set the not-null probability
1292 // to the maximum (PROB_MAX). For an explicit check the probability
1293 // is set to a smaller value.
1294 if (null_control != NULL || too_many_traps(reason)) {
1295 // probability is less likely
1296 ok_prob = PROB_LIKELY_MAG(3);
1297 } else if (!assert_null &&
1298 (ImplicitNullCheckThreshold > 0) &&
1299 method() != NULL &&
1300 (method()->method_data()->trap_count(reason)
1301 >= (uint)ImplicitNullCheckThreshold)) {
1302 ok_prob = PROB_LIKELY_MAG(3);
1303 }
1304
1305 if (null_control != NULL) {
1306 IfNode* iff = create_and_map_if(control(), tst, ok_prob, COUNT_UNKNOWN);
1307 Node* null_true = _gvn.transform( new (C) IfFalseNode(iff));
1308 set_control( _gvn.transform( new (C) IfTrueNode(iff)));
1309 if (null_true == top())
1310 explicit_null_checks_elided++;
1311 (*null_control) = null_true;
1312 } else {
1313 BuildCutout unless(this, tst, ok_prob);
1314 // Check for optimizer eliding test at parse time
1315 if (stopped()) {
1316 // Failure not possible; do not bother making uncommon trap.
1317 explicit_null_checks_elided++;
1318 } else if (assert_null) {
1319 uncommon_trap(reason,
1320 Deoptimization::Action_make_not_entrant,
1321 NULL, "assert_null");
1322 } else {
1323 replace_in_map(value, zerocon(type));
1324 builtin_throw(reason);
1325 }
1326 }
1327
1328 // Must throw exception, fall-thru not possible?
1329 if (stopped()) {
1330 return top(); // No result
1331 }
1332
1333 if (assert_null) {
1334 // Cast obj to null on this path.
1335 replace_in_map(value, zerocon(type));
1336 return zerocon(type);
1337 }
1338
1339 // Cast obj to not-null on this path, if there is no null_control.
1340 // (If there is a null_control, a non-null value may come back to haunt us.)
1341 if (type == T_OBJECT) {
1342 Node* cast = cast_not_null(value, false);
1343 if (null_control == NULL || (*null_control) == top())
1344 replace_in_map(value, cast);
1345 value = cast;
1346 }
1347
1348 return value;
1349 }
1350
1351
1352 //------------------------------cast_not_null----------------------------------
1353 // Cast obj to not-null on this path
1354 Node* GraphKit::cast_not_null(Node* obj, bool do_replace_in_map) {
1355 const Type *t = _gvn.type(obj);
1356 const Type *t_not_null = t->join(TypePtr::NOTNULL);
1357 // Object is already not-null?
1358 if( t == t_not_null ) return obj;
1359
1360 Node *cast = new (C) CastPPNode(obj,t_not_null);
1361 cast->init_req(0, control());
1362 cast = _gvn.transform( cast );
1363
1364 // Scan for instances of 'obj' in the current JVM mapping.
1365 // These instances are known to be not-null after the test.
1366 if (do_replace_in_map)
1367 replace_in_map(obj, cast);
1368
1369 return cast; // Return casted value
1370 }
1371
1372
1373 //--------------------------replace_in_map-------------------------------------
1374 void GraphKit::replace_in_map(Node* old, Node* neww) {
1375 this->map()->replace_edge(old, neww);
1376
1377 // Note: This operation potentially replaces any edge
1378 // on the map. This includes locals, stack, and monitors
1379 // of the current (innermost) JVM state.
1380
1381 // We can consider replacing in caller maps.
1382 // The idea would be that an inlined function's null checks
1383 // can be shared with the entire inlining tree.
1384 // The expense of doing this is that the PreserveJVMState class
1385 // would have to preserve caller states too, with a deep copy.
1386 }
1387
1388
1389 //=============================================================================
1390 //--------------------------------memory---------------------------------------
1391 Node* GraphKit::memory(uint alias_idx) {
1392 MergeMemNode* mem = merged_memory();
1393 Node* p = mem->memory_at(alias_idx);
1394 _gvn.set_type(p, Type::MEMORY); // must be mapped
1395 return p;
1396 }
1397
1398 //-----------------------------reset_memory------------------------------------
1399 Node* GraphKit::reset_memory() {
1400 Node* mem = map()->memory();
1401 // do not use this node for any more parsing!
1402 debug_only( map()->set_memory((Node*)NULL) );
1403 return _gvn.transform( mem );
1404 }
1405
1406 //------------------------------set_all_memory---------------------------------
1407 void GraphKit::set_all_memory(Node* newmem) {
1408 Node* mergemem = MergeMemNode::make(C, newmem);
1409 gvn().set_type_bottom(mergemem);
1410 map()->set_memory(mergemem);
1411 }
1412
1413 //------------------------------set_all_memory_call----------------------------
1414 void GraphKit::set_all_memory_call(Node* call, bool separate_io_proj) {
1415 Node* newmem = _gvn.transform( new (C) ProjNode(call, TypeFunc::Memory, separate_io_proj) );
1416 set_all_memory(newmem);
1417 }
1418
1419 //=============================================================================
1420 //
1421 // parser factory methods for MemNodes
1422 //
1423 // These are layered on top of the factory methods in LoadNode and StoreNode,
1424 // and integrate with the parser's memory state and _gvn engine.
1425 //
1426
1427 // factory methods in "int adr_idx"
1428 Node* GraphKit::make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,
1429 int adr_idx,
1430 bool require_atomic_access) {
1431 assert(adr_idx != Compile::AliasIdxTop, "use other make_load factory" );
1432 const TypePtr* adr_type = NULL; // debug-mode-only argument
1433 debug_only(adr_type = C->get_adr_type(adr_idx));
1434 Node* mem = memory(adr_idx);
1435 Node* ld;
1436 if (require_atomic_access && bt == T_LONG) {
1437 ld = LoadLNode::make_atomic(C, ctl, mem, adr, adr_type, t);
1438 } else {
1439 ld = LoadNode::make(_gvn, ctl, mem, adr, adr_type, t, bt);
1440 }
1441 return _gvn.transform(ld);
1442 }
1443
1444 Node* GraphKit::store_to_memory(Node* ctl, Node* adr, Node *val, BasicType bt,
1445 int adr_idx,
1446 bool require_atomic_access) {
1447 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1448 const TypePtr* adr_type = NULL;
1449 debug_only(adr_type = C->get_adr_type(adr_idx));
1450 Node *mem = memory(adr_idx);
1451 Node* st;
1452 if (require_atomic_access && bt == T_LONG) {
1453 st = StoreLNode::make_atomic(C, ctl, mem, adr, adr_type, val);
1454 } else {
1455 st = StoreNode::make(_gvn, ctl, mem, adr, adr_type, val, bt);
1456 }
1457 st = _gvn.transform(st);
1458 set_memory(st, adr_idx);
1459 // Back-to-back stores can only remove intermediate store with DU info
1460 // so push on worklist for optimizer.
1461 if (mem->req() > MemNode::Address && adr == mem->in(MemNode::Address))
1462 record_for_igvn(st);
1463
1464 return st;
1465 }
1466
1467
1468 void GraphKit::pre_barrier(bool do_load,
1469 Node* ctl,
1470 Node* obj,
1471 Node* adr,
1472 uint adr_idx,
1473 Node* val,
1474 const TypeOopPtr* val_type,
1475 Node* pre_val,
1476 BasicType bt) {
1477
1478 BarrierSet* bs = Universe::heap()->barrier_set();
1479 set_control(ctl);
1480 switch (bs->kind()) {
1481 case BarrierSet::G1SATBCT:
1482 case BarrierSet::G1SATBCTLogging:
1483 g1_write_barrier_pre(do_load, obj, adr, adr_idx, val, val_type, pre_val, bt);
1484 break;
1485
1486 case BarrierSet::CardTableModRef:
1487 case BarrierSet::CardTableExtension:
1488 case BarrierSet::ModRef:
1489 break;
1490
1491 case BarrierSet::Other:
1492 default :
1493 ShouldNotReachHere();
1494
1495 }
1496 }
1497
1498 void GraphKit::post_barrier(Node* ctl,
1499 Node* store,
1500 Node* obj,
1501 Node* adr,
1502 uint adr_idx,
1503 Node* val,
1504 BasicType bt,
1505 bool use_precise) {
1506 BarrierSet* bs = Universe::heap()->barrier_set();
1507 set_control(ctl);
1508 switch (bs->kind()) {
1509 case BarrierSet::G1SATBCT:
1510 case BarrierSet::G1SATBCTLogging:
1511 g1_write_barrier_post(store, obj, adr, adr_idx, val, bt, use_precise);
1512 break;
1513
1514 case BarrierSet::CardTableModRef:
1515 case BarrierSet::CardTableExtension:
1516 write_barrier_post(store, obj, adr, adr_idx, val, use_precise);
1517 break;
1518
1519 case BarrierSet::ModRef:
1520 break;
1521
1522 case BarrierSet::Other:
1523 default :
1524 ShouldNotReachHere();
1525
1526 }
1527 }
1528
1529 Node* GraphKit::store_oop(Node* ctl,
1530 Node* obj,
1531 Node* adr,
1532 const TypePtr* adr_type,
1533 Node* val,
1534 const TypeOopPtr* val_type,
1535 BasicType bt,
1536 bool use_precise) {
1537 // Transformation of a value which could be NULL pointer (CastPP #NULL)
1538 // could be delayed during Parse (for example, in adjust_map_after_if()).
1539 // Execute transformation here to avoid barrier generation in such case.
1540 if (_gvn.type(val) == TypePtr::NULL_PTR)
1541 val = _gvn.makecon(TypePtr::NULL_PTR);
1542
1543 set_control(ctl);
1544 if (stopped()) return top(); // Dead path ?
1545
1546 assert(bt == T_OBJECT, "sanity");
1547 assert(val != NULL, "not dead path");
1548 uint adr_idx = C->get_alias_index(adr_type);
1549 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1550
1551 pre_barrier(true /* do_load */,
1552 control(), obj, adr, adr_idx, val, val_type,
1553 NULL /* pre_val */,
1554 bt);
1555
1556 Node* store = store_to_memory(control(), adr, val, bt, adr_idx);
1557 post_barrier(control(), store, obj, adr, adr_idx, val, bt, use_precise);
1558 return store;
1559 }
1560
1561 // Could be an array or object we don't know at compile time (unsafe ref.)
1562 Node* GraphKit::store_oop_to_unknown(Node* ctl,
1563 Node* obj, // containing obj
1564 Node* adr, // actual adress to store val at
1565 const TypePtr* adr_type,
1566 Node* val,
1567 BasicType bt) {
1568 Compile::AliasType* at = C->alias_type(adr_type);
1569 const TypeOopPtr* val_type = NULL;
1570 if (adr_type->isa_instptr()) {
1571 if (at->field() != NULL) {
1572 // known field. This code is a copy of the do_put_xxx logic.
1573 ciField* field = at->field();
1574 if (!field->type()->is_loaded()) {
1575 val_type = TypeInstPtr::BOTTOM;
1576 } else {
1577 val_type = TypeOopPtr::make_from_klass(field->type()->as_klass());
1578 }
1579 }
1580 } else if (adr_type->isa_aryptr()) {
1581 val_type = adr_type->is_aryptr()->elem()->make_oopptr();
1582 }
1583 if (val_type == NULL) {
1584 val_type = TypeInstPtr::BOTTOM;
1585 }
1586 return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, true);
1587 }
1588
1589
1590 //-------------------------array_element_address-------------------------
1591 Node* GraphKit::array_element_address(Node* ary, Node* idx, BasicType elembt,
1592 const TypeInt* sizetype) {
1593 uint shift = exact_log2(type2aelembytes(elembt));
1594 uint header = arrayOopDesc::base_offset_in_bytes(elembt);
1595
1596 // short-circuit a common case (saves lots of confusing waste motion)
1597 jint idx_con = find_int_con(idx, -1);
1598 if (idx_con >= 0) {
1599 intptr_t offset = header + ((intptr_t)idx_con << shift);
1600 return basic_plus_adr(ary, offset);
1601 }
1602
1603 // must be correct type for alignment purposes
1604 Node* base = basic_plus_adr(ary, header);
1605 #ifdef _LP64
1606 // The scaled index operand to AddP must be a clean 64-bit value.
1607 // Java allows a 32-bit int to be incremented to a negative
1608 // value, which appears in a 64-bit register as a large
1609 // positive number. Using that large positive number as an
1610 // operand in pointer arithmetic has bad consequences.
1611 // On the other hand, 32-bit overflow is rare, and the possibility
1612 // can often be excluded, if we annotate the ConvI2L node with
1613 // a type assertion that its value is known to be a small positive
1614 // number. (The prior range check has ensured this.)
1615 // This assertion is used by ConvI2LNode::Ideal.
1616 int index_max = max_jint - 1; // array size is max_jint, index is one less
1617 if (sizetype != NULL) index_max = sizetype->_hi - 1;
1618 const TypeLong* lidxtype = TypeLong::make(CONST64(0), index_max, Type::WidenMax);
1619 idx = _gvn.transform( new (C) ConvI2LNode(idx, lidxtype) );
1620 #endif
1621 Node* scale = _gvn.transform( new (C) LShiftXNode(idx, intcon(shift)) );
1622 return basic_plus_adr(ary, base, scale);
1623 }
1624
1625 //-------------------------load_array_element-------------------------
1626 Node* GraphKit::load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype) {
1627 const Type* elemtype = arytype->elem();
1628 BasicType elembt = elemtype->array_element_basic_type();
1629 Node* adr = array_element_address(ary, idx, elembt, arytype->size());
1630 Node* ld = make_load(ctl, adr, elemtype, elembt, arytype);
1631 return ld;
1632 }
1633
1634 //-------------------------set_arguments_for_java_call-------------------------
1635 // Arguments (pre-popped from the stack) are taken from the JVMS.
1636 void GraphKit::set_arguments_for_java_call(CallJavaNode* call) {
1637 // Add the call arguments:
1638 uint nargs = call->method()->arg_size();
1639 for (uint i = 0; i < nargs; i++) {
1640 Node* arg = argument(i);
1641 call->init_req(i + TypeFunc::Parms, arg);
1642 }
1643 }
1644
1645 //---------------------------set_edges_for_java_call---------------------------
1646 // Connect a newly created call into the current JVMS.
1647 // A return value node (if any) is returned from set_edges_for_java_call.
1648 void GraphKit::set_edges_for_java_call(CallJavaNode* call, bool must_throw, bool separate_io_proj) {
1649
1650 // Add the predefined inputs:
1651 call->init_req( TypeFunc::Control, control() );
1652 call->init_req( TypeFunc::I_O , i_o() );
1653 call->init_req( TypeFunc::Memory , reset_memory() );
1654 call->init_req( TypeFunc::FramePtr, frameptr() );
1655 call->init_req( TypeFunc::ReturnAdr, top() );
1656
1657 add_safepoint_edges(call, must_throw);
1658
1659 Node* xcall = _gvn.transform(call);
1660
1661 if (xcall == top()) {
1662 set_control(top());
1663 return;
1664 }
1665 assert(xcall == call, "call identity is stable");
1666
1667 // Re-use the current map to produce the result.
1668
1669 set_control(_gvn.transform(new (C) ProjNode(call, TypeFunc::Control)));
1670 set_i_o( _gvn.transform(new (C) ProjNode(call, TypeFunc::I_O , separate_io_proj)));
1671 set_all_memory_call(xcall, separate_io_proj);
1672
1673 //return xcall; // no need, caller already has it
1674 }
1675
1676 Node* GraphKit::set_results_for_java_call(CallJavaNode* call, bool separate_io_proj) {
1677 if (stopped()) return top(); // maybe the call folded up?
1678
1679 // Capture the return value, if any.
1680 Node* ret;
1681 if (call->method() == NULL ||
1682 call->method()->return_type()->basic_type() == T_VOID)
1683 ret = top();
1684 else ret = _gvn.transform(new (C) ProjNode(call, TypeFunc::Parms));
1685
1686 // Note: Since any out-of-line call can produce an exception,
1687 // we always insert an I_O projection from the call into the result.
1688
1689 make_slow_call_ex(call, env()->Throwable_klass(), separate_io_proj);
1690
1691 if (separate_io_proj) {
1692 // The caller requested separate projections be used by the fall
1693 // through and exceptional paths, so replace the projections for
1694 // the fall through path.
1695 set_i_o(_gvn.transform( new (C) ProjNode(call, TypeFunc::I_O) ));
1696 set_all_memory(_gvn.transform( new (C) ProjNode(call, TypeFunc::Memory) ));
1697 }
1698 return ret;
1699 }
1700
1701 //--------------------set_predefined_input_for_runtime_call--------------------
1702 // Reading and setting the memory state is way conservative here.
1703 // The real problem is that I am not doing real Type analysis on memory,
1704 // so I cannot distinguish card mark stores from other stores. Across a GC
1705 // point the Store Barrier and the card mark memory has to agree. I cannot
1706 // have a card mark store and its barrier split across the GC point from
1707 // either above or below. Here I get that to happen by reading ALL of memory.
1708 // A better answer would be to separate out card marks from other memory.
1709 // For now, return the input memory state, so that it can be reused
1710 // after the call, if this call has restricted memory effects.
1711 Node* GraphKit::set_predefined_input_for_runtime_call(SafePointNode* call) {
1712 // Set fixed predefined input arguments
1713 Node* memory = reset_memory();
1714 call->init_req( TypeFunc::Control, control() );
1715 call->init_req( TypeFunc::I_O, top() ); // does no i/o
1716 call->init_req( TypeFunc::Memory, memory ); // may gc ptrs
1717 call->init_req( TypeFunc::FramePtr, frameptr() );
1718 call->init_req( TypeFunc::ReturnAdr, top() );
1719 return memory;
1720 }
1721
1722 //-------------------set_predefined_output_for_runtime_call--------------------
1723 // Set control and memory (not i_o) from the call.
1724 // If keep_mem is not NULL, use it for the output state,
1725 // except for the RawPtr output of the call, if hook_mem is TypeRawPtr::BOTTOM.
1726 // If hook_mem is NULL, this call produces no memory effects at all.
1727 // If hook_mem is a Java-visible memory slice (such as arraycopy operands),
1728 // then only that memory slice is taken from the call.
1729 // In the last case, we must put an appropriate memory barrier before
1730 // the call, so as to create the correct anti-dependencies on loads
1731 // preceding the call.
1732 void GraphKit::set_predefined_output_for_runtime_call(Node* call,
1733 Node* keep_mem,
1734 const TypePtr* hook_mem) {
1735 // no i/o
1736 set_control(_gvn.transform( new (C) ProjNode(call,TypeFunc::Control) ));
1737 if (keep_mem) {
1738 // First clone the existing memory state
1739 set_all_memory(keep_mem);
1740 if (hook_mem != NULL) {
1741 // Make memory for the call
1742 Node* mem = _gvn.transform( new (C) ProjNode(call, TypeFunc::Memory) );
1743 // Set the RawPtr memory state only. This covers all the heap top/GC stuff
1744 // We also use hook_mem to extract specific effects from arraycopy stubs.
1745 set_memory(mem, hook_mem);
1746 }
1747 // ...else the call has NO memory effects.
1748
1749 // Make sure the call advertises its memory effects precisely.
1750 // This lets us build accurate anti-dependences in gcm.cpp.
1751 assert(C->alias_type(call->adr_type()) == C->alias_type(hook_mem),
1752 "call node must be constructed correctly");
1753 } else {
1754 assert(hook_mem == NULL, "");
1755 // This is not a "slow path" call; all memory comes from the call.
1756 set_all_memory_call(call);
1757 }
1758 }
1759
1760
1761 // Replace the call with the current state of the kit.
1762 void GraphKit::replace_call(CallNode* call, Node* result) {
1763 JVMState* ejvms = NULL;
1764 if (has_exceptions()) {
1765 ejvms = transfer_exceptions_into_jvms();
1766 }
1767
1768 SafePointNode* final_state = stop();
1769
1770 // Find all the needed outputs of this call
1771 CallProjections callprojs;
1772 call->extract_projections(&callprojs, true);
1773
1774 // Replace all the old call edges with the edges from the inlining result
1775 C->gvn_replace_by(callprojs.fallthrough_catchproj, final_state->in(TypeFunc::Control));
1776 C->gvn_replace_by(callprojs.fallthrough_memproj, final_state->in(TypeFunc::Memory));
1777 C->gvn_replace_by(callprojs.fallthrough_ioproj, final_state->in(TypeFunc::I_O));
1778 Node* final_mem = final_state->in(TypeFunc::Memory);
1779
1780 // Replace the result with the new result if it exists and is used
1781 if (callprojs.resproj != NULL && result != NULL) {
1782 C->gvn_replace_by(callprojs.resproj, result);
1783 }
1784
1785 if (ejvms == NULL) {
1786 // No exception edges to simply kill off those paths
1787 C->gvn_replace_by(callprojs.catchall_catchproj, C->top());
1788 C->gvn_replace_by(callprojs.catchall_memproj, C->top());
1789 C->gvn_replace_by(callprojs.catchall_ioproj, C->top());
1790
1791 // Replace the old exception object with top
1792 if (callprojs.exobj != NULL) {
1793 C->gvn_replace_by(callprojs.exobj, C->top());
1794 }
1795 } else {
1796 GraphKit ekit(ejvms);
1797
1798 // Load my combined exception state into the kit, with all phis transformed:
1799 SafePointNode* ex_map = ekit.combine_and_pop_all_exception_states();
1800
1801 Node* ex_oop = ekit.use_exception_state(ex_map);
1802
1803 C->gvn_replace_by(callprojs.catchall_catchproj, ekit.control());
1804 C->gvn_replace_by(callprojs.catchall_memproj, ekit.reset_memory());
1805 C->gvn_replace_by(callprojs.catchall_ioproj, ekit.i_o());
1806
1807 // Replace the old exception object with the newly created one
1808 if (callprojs.exobj != NULL) {
1809 C->gvn_replace_by(callprojs.exobj, ex_oop);
1810 }
1811 }
1812
1813 // Disconnect the call from the graph
1814 call->disconnect_inputs(NULL, C);
1815 C->gvn_replace_by(call, C->top());
1816
1817 // Clean up any MergeMems that feed other MergeMems since the
1818 // optimizer doesn't like that.
1819 if (final_mem->is_MergeMem()) {
1820 Node_List wl;
1821 for (SimpleDUIterator i(final_mem); i.has_next(); i.next()) {
1822 Node* m = i.get();
1823 if (m->is_MergeMem() && !wl.contains(m)) {
1824 wl.push(m);
1825 }
1826 }
1827 while (wl.size() > 0) {
1828 _gvn.transform(wl.pop());
1829 }
1830 }
1831 }
1832
1833
1834 //------------------------------increment_counter------------------------------
1835 // for statistics: increment a VM counter by 1
1836
1837 void GraphKit::increment_counter(address counter_addr) {
1838 Node* adr1 = makecon(TypeRawPtr::make(counter_addr));
1839 increment_counter(adr1);
1840 }
1841
1842 void GraphKit::increment_counter(Node* counter_addr) {
1843 int adr_type = Compile::AliasIdxRaw;
1844 Node* ctrl = control();
1845 Node* cnt = make_load(ctrl, counter_addr, TypeInt::INT, T_INT, adr_type);
1846 Node* incr = _gvn.transform(new (C) AddINode(cnt, _gvn.intcon(1)));
1847 store_to_memory( ctrl, counter_addr, incr, T_INT, adr_type );
1848 }
1849
1850
1851 //------------------------------uncommon_trap----------------------------------
1852 // Bail out to the interpreter in mid-method. Implemented by calling the
1853 // uncommon_trap blob. This helper function inserts a runtime call with the
1854 // right debug info.
1855 void GraphKit::uncommon_trap(int trap_request,
1856 ciKlass* klass, const char* comment,
1857 bool must_throw,
1858 bool keep_exact_action) {
1859 if (failing()) stop();
1860 if (stopped()) return; // trap reachable?
1861
1862 // Note: If ProfileTraps is true, and if a deopt. actually
1863 // occurs here, the runtime will make sure an MDO exists. There is
1864 // no need to call method()->ensure_method_data() at this point.
1865
1866 // Set the stack pointer to the right value for reexecution:
1867 set_sp(reexecute_sp());
1868
1869 #ifdef ASSERT
1870 if (!must_throw) {
1871 // Make sure the stack has at least enough depth to execute
1872 // the current bytecode.
1873 int inputs, ignored_depth;
1874 if (compute_stack_effects(inputs, ignored_depth)) {
1875 assert(sp() >= inputs, err_msg_res("must have enough JVMS stack to execute %s: sp=%d, inputs=%d",
1876 Bytecodes::name(java_bc()), sp(), inputs));
1877 }
1878 }
1879 #endif
1880
1881 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
1882 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request);
1883
1884 switch (action) {
1885 case Deoptimization::Action_maybe_recompile:
1886 case Deoptimization::Action_reinterpret:
1887 // Temporary fix for 6529811 to allow virtual calls to be sure they
1888 // get the chance to go from mono->bi->mega
1889 if (!keep_exact_action &&
1890 Deoptimization::trap_request_index(trap_request) < 0 &&
1891 too_many_recompiles(reason)) {
1892 // This BCI is causing too many recompilations.
1893 action = Deoptimization::Action_none;
1894 trap_request = Deoptimization::make_trap_request(reason, action);
1895 } else {
1896 C->set_trap_can_recompile(true);
1897 }
1898 break;
1899 case Deoptimization::Action_make_not_entrant:
1900 C->set_trap_can_recompile(true);
1901 break;
1902 #ifdef ASSERT
1903 case Deoptimization::Action_none:
1904 case Deoptimization::Action_make_not_compilable:
1905 break;
1906 default:
1907 fatal(err_msg_res("unknown action %d: %s", action, Deoptimization::trap_action_name(action)));
1908 break;
1909 #endif
1910 }
1911
1912 if (TraceOptoParse) {
1913 char buf[100];
1914 tty->print_cr("Uncommon trap %s at bci:%d",
1915 Deoptimization::format_trap_request(buf, sizeof(buf),
1916 trap_request), bci());
1917 }
1918
1919 CompileLog* log = C->log();
1920 if (log != NULL) {
1921 int kid = (klass == NULL)? -1: log->identify(klass);
1922 log->begin_elem("uncommon_trap bci='%d'", bci());
1923 char buf[100];
1924 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
1925 trap_request));
1926 if (kid >= 0) log->print(" klass='%d'", kid);
1927 if (comment != NULL) log->print(" comment='%s'", comment);
1928 log->end_elem();
1929 }
1930
1931 // Make sure any guarding test views this path as very unlikely
1932 Node *i0 = control()->in(0);
1933 if (i0 != NULL && i0->is_If()) { // Found a guarding if test?
1934 IfNode *iff = i0->as_If();
1935 float f = iff->_prob; // Get prob
1936 if (control()->Opcode() == Op_IfTrue) {
1937 if (f > PROB_UNLIKELY_MAG(4))
1938 iff->_prob = PROB_MIN;
1939 } else {
1940 if (f < PROB_LIKELY_MAG(4))
1941 iff->_prob = PROB_MAX;
1942 }
1943 }
1944
1945 // Clear out dead values from the debug info.
1946 kill_dead_locals();
1947
1948 // Now insert the uncommon trap subroutine call
1949 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
1950 const TypePtr* no_memory_effects = NULL;
1951 // Pass the index of the class to be loaded
1952 Node* call = make_runtime_call(RC_NO_LEAF | RC_UNCOMMON |
1953 (must_throw ? RC_MUST_THROW : 0),
1954 OptoRuntime::uncommon_trap_Type(),
1955 call_addr, "uncommon_trap", no_memory_effects,
1956 intcon(trap_request));
1957 assert(call->as_CallStaticJava()->uncommon_trap_request() == trap_request,
1958 "must extract request correctly from the graph");
1959 assert(trap_request != 0, "zero value reserved by uncommon_trap_request");
1960
1961 call->set_req(TypeFunc::ReturnAdr, returnadr());
1962 // The debug info is the only real input to this call.
1963
1964 // Halt-and-catch fire here. The above call should never return!
1965 HaltNode* halt = new(C) HaltNode(control(), frameptr());
1966 _gvn.set_type_bottom(halt);
1967 root()->add_req(halt);
1968
1969 stop_and_kill_map();
1970 }
1971
1972
1973 //--------------------------just_allocated_object------------------------------
1974 // Report the object that was just allocated.
1975 // It must be the case that there are no intervening safepoints.
1976 // We use this to determine if an object is so "fresh" that
1977 // it does not require card marks.
1978 Node* GraphKit::just_allocated_object(Node* current_control) {
1979 if (C->recent_alloc_ctl() == current_control)
1980 return C->recent_alloc_obj();
1981 return NULL;
1982 }
1983
1984
1985 void GraphKit::round_double_arguments(ciMethod* dest_method) {
1986 // (Note: TypeFunc::make has a cache that makes this fast.)
1987 const TypeFunc* tf = TypeFunc::make(dest_method);
1988 int nargs = tf->_domain->_cnt - TypeFunc::Parms;
1989 for (int j = 0; j < nargs; j++) {
1990 const Type *targ = tf->_domain->field_at(j + TypeFunc::Parms);
1991 if( targ->basic_type() == T_DOUBLE ) {
1992 // If any parameters are doubles, they must be rounded before
1993 // the call, dstore_rounding does gvn.transform
1994 Node *arg = argument(j);
1995 arg = dstore_rounding(arg);
1996 set_argument(j, arg);
1997 }
1998 }
1999 }
2000
2001 void GraphKit::round_double_result(ciMethod* dest_method) {
2002 // A non-strict method may return a double value which has an extended
2003 // exponent, but this must not be visible in a caller which is 'strict'
2004 // If a strict caller invokes a non-strict callee, round a double result
2005
2006 BasicType result_type = dest_method->return_type()->basic_type();
2007 assert( method() != NULL, "must have caller context");
2008 if( result_type == T_DOUBLE && method()->is_strict() && !dest_method->is_strict() ) {
2009 // Destination method's return value is on top of stack
2010 // dstore_rounding() does gvn.transform
2011 Node *result = pop_pair();
2012 result = dstore_rounding(result);
2013 push_pair(result);
2014 }
2015 }
2016
2017 // rounding for strict float precision conformance
2018 Node* GraphKit::precision_rounding(Node* n) {
2019 return UseStrictFP && _method->flags().is_strict()
2020 && UseSSE == 0 && Matcher::strict_fp_requires_explicit_rounding
2021 ? _gvn.transform( new (C) RoundFloatNode(0, n) )
2022 : n;
2023 }
2024
2025 // rounding for strict double precision conformance
2026 Node* GraphKit::dprecision_rounding(Node *n) {
2027 return UseStrictFP && _method->flags().is_strict()
2028 && UseSSE <= 1 && Matcher::strict_fp_requires_explicit_rounding
2029 ? _gvn.transform( new (C) RoundDoubleNode(0, n) )
2030 : n;
2031 }
2032
2033 // rounding for non-strict double stores
2034 Node* GraphKit::dstore_rounding(Node* n) {
2035 return Matcher::strict_fp_requires_explicit_rounding
2036 && UseSSE <= 1
2037 ? _gvn.transform( new (C) RoundDoubleNode(0, n) )
2038 : n;
2039 }
2040
2041 //=============================================================================
2042 // Generate a fast path/slow path idiom. Graph looks like:
2043 // [foo] indicates that 'foo' is a parameter
2044 //
2045 // [in] NULL
2046 // \ /
2047 // CmpP
2048 // Bool ne
2049 // If
2050 // / \
2051 // True False-<2>
2052 // / |
2053 // / cast_not_null
2054 // Load | | ^
2055 // [fast_test] | |
2056 // gvn to opt_test | |
2057 // / \ | <1>
2058 // True False |
2059 // | \\ |
2060 // [slow_call] \[fast_result]
2061 // Ctl Val \ \
2062 // | \ \
2063 // Catch <1> \ \
2064 // / \ ^ \ \
2065 // Ex No_Ex | \ \
2066 // | \ \ | \ <2> \
2067 // ... \ [slow_res] | | \ [null_result]
2068 // \ \--+--+--- | |
2069 // \ | / \ | /
2070 // --------Region Phi
2071 //
2072 //=============================================================================
2073 // Code is structured as a series of driver functions all called 'do_XXX' that
2074 // call a set of helper functions. Helper functions first, then drivers.
2075
2076 //------------------------------null_check_oop---------------------------------
2077 // Null check oop. Set null-path control into Region in slot 3.
2078 // Make a cast-not-nullness use the other not-null control. Return cast.
2079 Node* GraphKit::null_check_oop(Node* value, Node* *null_control,
2080 bool never_see_null) {
2081 // Initial NULL check taken path
2082 (*null_control) = top();
2083 Node* cast = null_check_common(value, T_OBJECT, false, null_control);
2084
2085 // Generate uncommon_trap:
2086 if (never_see_null && (*null_control) != top()) {
2087 // If we see an unexpected null at a check-cast we record it and force a
2088 // recompile; the offending check-cast will be compiled to handle NULLs.
2089 // If we see more than one offending BCI, then all checkcasts in the
2090 // method will be compiled to handle NULLs.
2091 PreserveJVMState pjvms(this);
2092 set_control(*null_control);
2093 replace_in_map(value, null());
2094 uncommon_trap(Deoptimization::Reason_null_check,
2095 Deoptimization::Action_make_not_entrant);
2096 (*null_control) = top(); // NULL path is dead
2097 }
2098
2099 // Cast away null-ness on the result
2100 return cast;
2101 }
2102
2103 //------------------------------opt_iff----------------------------------------
2104 // Optimize the fast-check IfNode. Set the fast-path region slot 2.
2105 // Return slow-path control.
2106 Node* GraphKit::opt_iff(Node* region, Node* iff) {
2107 IfNode *opt_iff = _gvn.transform(iff)->as_If();
2108
2109 // Fast path taken; set region slot 2
2110 Node *fast_taken = _gvn.transform( new (C) IfFalseNode(opt_iff) );
2111 region->init_req(2,fast_taken); // Capture fast-control
2112
2113 // Fast path not-taken, i.e. slow path
2114 Node *slow_taken = _gvn.transform( new (C) IfTrueNode(opt_iff) );
2115 return slow_taken;
2116 }
2117
2118 //-----------------------------make_runtime_call-------------------------------
2119 Node* GraphKit::make_runtime_call(int flags,
2120 const TypeFunc* call_type, address call_addr,
2121 const char* call_name,
2122 const TypePtr* adr_type,
2123 // The following parms are all optional.
2124 // The first NULL ends the list.
2125 Node* parm0, Node* parm1,
2126 Node* parm2, Node* parm3,
2127 Node* parm4, Node* parm5,
2128 Node* parm6, Node* parm7) {
2129 // Slow-path call
2130 bool is_leaf = !(flags & RC_NO_LEAF);
2131 bool has_io = (!is_leaf && !(flags & RC_NO_IO));
2132 if (call_name == NULL) {
2133 assert(!is_leaf, "must supply name for leaf");
2134 call_name = OptoRuntime::stub_name(call_addr);
2135 }
2136 CallNode* call;
2137 if (!is_leaf) {
2138 call = new(C) CallStaticJavaNode(call_type, call_addr, call_name,
2139 bci(), adr_type);
2140 } else if (flags & RC_NO_FP) {
2141 call = new(C) CallLeafNoFPNode(call_type, call_addr, call_name, adr_type);
2142 } else {
2143 call = new(C) CallLeafNode(call_type, call_addr, call_name, adr_type);
2144 }
2145
2146 // The following is similar to set_edges_for_java_call,
2147 // except that the memory effects of the call are restricted to AliasIdxRaw.
2148
2149 // Slow path call has no side-effects, uses few values
2150 bool wide_in = !(flags & RC_NARROW_MEM);
2151 bool wide_out = (C->get_alias_index(adr_type) == Compile::AliasIdxBot);
2152
2153 Node* prev_mem = NULL;
2154 if (wide_in) {
2155 prev_mem = set_predefined_input_for_runtime_call(call);
2156 } else {
2157 assert(!wide_out, "narrow in => narrow out");
2158 Node* narrow_mem = memory(adr_type);
2159 prev_mem = reset_memory();
2160 map()->set_memory(narrow_mem);
2161 set_predefined_input_for_runtime_call(call);
2162 }
2163
2164 // Hook each parm in order. Stop looking at the first NULL.
2165 if (parm0 != NULL) { call->init_req(TypeFunc::Parms+0, parm0);
2166 if (parm1 != NULL) { call->init_req(TypeFunc::Parms+1, parm1);
2167 if (parm2 != NULL) { call->init_req(TypeFunc::Parms+2, parm2);
2168 if (parm3 != NULL) { call->init_req(TypeFunc::Parms+3, parm3);
2169 if (parm4 != NULL) { call->init_req(TypeFunc::Parms+4, parm4);
2170 if (parm5 != NULL) { call->init_req(TypeFunc::Parms+5, parm5);
2171 if (parm6 != NULL) { call->init_req(TypeFunc::Parms+6, parm6);
2172 if (parm7 != NULL) { call->init_req(TypeFunc::Parms+7, parm7);
2173 /* close each nested if ===> */ } } } } } } } }
2174 assert(call->in(call->req()-1) != NULL, "must initialize all parms");
2175
2176 if (!is_leaf) {
2177 // Non-leaves can block and take safepoints:
2178 add_safepoint_edges(call, ((flags & RC_MUST_THROW) != 0));
2179 }
2180 // Non-leaves can throw exceptions:
2181 if (has_io) {
2182 call->set_req(TypeFunc::I_O, i_o());
2183 }
2184
2185 if (flags & RC_UNCOMMON) {
2186 // Set the count to a tiny probability. Cf. Estimate_Block_Frequency.
2187 // (An "if" probability corresponds roughly to an unconditional count.
2188 // Sort of.)
2189 call->set_cnt(PROB_UNLIKELY_MAG(4));
2190 }
2191
2192 Node* c = _gvn.transform(call);
2193 assert(c == call, "cannot disappear");
2194
2195 if (wide_out) {
2196 // Slow path call has full side-effects.
2197 set_predefined_output_for_runtime_call(call);
2198 } else {
2199 // Slow path call has few side-effects, and/or sets few values.
2200 set_predefined_output_for_runtime_call(call, prev_mem, adr_type);
2201 }
2202
2203 if (has_io) {
2204 set_i_o(_gvn.transform(new (C) ProjNode(call, TypeFunc::I_O)));
2205 }
2206 return call;
2207
2208 }
2209
2210 //------------------------------merge_memory-----------------------------------
2211 // Merge memory from one path into the current memory state.
2212 void GraphKit::merge_memory(Node* new_mem, Node* region, int new_path) {
2213 for (MergeMemStream mms(merged_memory(), new_mem->as_MergeMem()); mms.next_non_empty2(); ) {
2214 Node* old_slice = mms.force_memory();
2215 Node* new_slice = mms.memory2();
2216 if (old_slice != new_slice) {
2217 PhiNode* phi;
2218 if (new_slice->is_Phi() && new_slice->as_Phi()->region() == region) {
2219 phi = new_slice->as_Phi();
2220 #ifdef ASSERT
2221 if (old_slice->is_Phi() && old_slice->as_Phi()->region() == region)
2222 old_slice = old_slice->in(new_path);
2223 // Caller is responsible for ensuring that any pre-existing
2224 // phis are already aware of old memory.
2225 int old_path = (new_path > 1) ? 1 : 2; // choose old_path != new_path
2226 assert(phi->in(old_path) == old_slice, "pre-existing phis OK");
2227 #endif
2228 mms.set_memory(phi);
2229 } else {
2230 phi = PhiNode::make(region, old_slice, Type::MEMORY, mms.adr_type(C));
2231 _gvn.set_type(phi, Type::MEMORY);
2232 phi->set_req(new_path, new_slice);
2233 mms.set_memory(_gvn.transform(phi)); // assume it is complete
2234 }
2235 }
2236 }
2237 }
2238
2239 //------------------------------make_slow_call_ex------------------------------
2240 // Make the exception handler hookups for the slow call
2241 void GraphKit::make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj) {
2242 if (stopped()) return;
2243
2244 // Make a catch node with just two handlers: fall-through and catch-all
2245 Node* i_o = _gvn.transform( new (C) ProjNode(call, TypeFunc::I_O, separate_io_proj) );
2246 Node* catc = _gvn.transform( new (C) CatchNode(control(), i_o, 2) );
2247 Node* norm = _gvn.transform( new (C) CatchProjNode(catc, CatchProjNode::fall_through_index, CatchProjNode::no_handler_bci) );
2248 Node* excp = _gvn.transform( new (C) CatchProjNode(catc, CatchProjNode::catch_all_index, CatchProjNode::no_handler_bci) );
2249
2250 { PreserveJVMState pjvms(this);
2251 set_control(excp);
2252 set_i_o(i_o);
2253
2254 if (excp != top()) {
2255 // Create an exception state also.
2256 // Use an exact type if the caller has specified a specific exception.
2257 const Type* ex_type = TypeOopPtr::make_from_klass_unique(ex_klass)->cast_to_ptr_type(TypePtr::NotNull);
2258 Node* ex_oop = new (C) CreateExNode(ex_type, control(), i_o);
2259 add_exception_state(make_exception_state(_gvn.transform(ex_oop)));
2260 }
2261 }
2262
2263 // Get the no-exception control from the CatchNode.
2264 set_control(norm);
2265 }
2266
2267
2268 //-------------------------------gen_subtype_check-----------------------------
2269 // Generate a subtyping check. Takes as input the subtype and supertype.
2270 // Returns 2 values: sets the default control() to the true path and returns
2271 // the false path. Only reads invariant memory; sets no (visible) memory.
2272 // The PartialSubtypeCheckNode sets the hidden 1-word cache in the encoding
2273 // but that's not exposed to the optimizer. This call also doesn't take in an
2274 // Object; if you wish to check an Object you need to load the Object's class
2275 // prior to coming here.
2276 Node* GraphKit::gen_subtype_check(Node* subklass, Node* superklass) {
2277 // Fast check for identical types, perhaps identical constants.
2278 // The types can even be identical non-constants, in cases
2279 // involving Array.newInstance, Object.clone, etc.
2280 if (subklass == superklass)
2281 return top(); // false path is dead; no test needed.
2282
2283 if (_gvn.type(superklass)->singleton()) {
2284 ciKlass* superk = _gvn.type(superklass)->is_klassptr()->klass();
2285 ciKlass* subk = _gvn.type(subklass)->is_klassptr()->klass();
2286
2287 // In the common case of an exact superklass, try to fold up the
2288 // test before generating code. You may ask, why not just generate
2289 // the code and then let it fold up? The answer is that the generated
2290 // code will necessarily include null checks, which do not always
2291 // completely fold away. If they are also needless, then they turn
2292 // into a performance loss. Example:
2293 // Foo[] fa = blah(); Foo x = fa[0]; fa[1] = x;
2294 // Here, the type of 'fa' is often exact, so the store check
2295 // of fa[1]=x will fold up, without testing the nullness of x.
2296 switch (static_subtype_check(superk, subk)) {
2297 case SSC_always_false:
2298 {
2299 Node* always_fail = control();
2300 set_control(top());
2301 return always_fail;
2302 }
2303 case SSC_always_true:
2304 return top();
2305 case SSC_easy_test:
2306 {
2307 // Just do a direct pointer compare and be done.
2308 Node* cmp = _gvn.transform( new(C) CmpPNode(subklass, superklass) );
2309 Node* bol = _gvn.transform( new(C) BoolNode(cmp, BoolTest::eq) );
2310 IfNode* iff = create_and_xform_if(control(), bol, PROB_STATIC_FREQUENT, COUNT_UNKNOWN);
2311 set_control( _gvn.transform( new(C) IfTrueNode (iff) ) );
2312 return _gvn.transform( new(C) IfFalseNode(iff) );
2313 }
2314 case SSC_full_test:
2315 break;
2316 default:
2317 ShouldNotReachHere();
2318 }
2319 }
2320
2321 // %%% Possible further optimization: Even if the superklass is not exact,
2322 // if the subklass is the unique subtype of the superklass, the check
2323 // will always succeed. We could leave a dependency behind to ensure this.
2324
2325 // First load the super-klass's check-offset
2326 Node *p1 = basic_plus_adr( superklass, superklass, in_bytes(Klass::super_check_offset_offset()) );
2327 Node *chk_off = _gvn.transform( new (C) LoadINode( NULL, memory(p1), p1, _gvn.type(p1)->is_ptr() ) );
2328 int cacheoff_con = in_bytes(Klass::secondary_super_cache_offset());
2329 bool might_be_cache = (find_int_con(chk_off, cacheoff_con) == cacheoff_con);
2330
2331 // Load from the sub-klass's super-class display list, or a 1-word cache of
2332 // the secondary superclass list, or a failing value with a sentinel offset
2333 // if the super-klass is an interface or exceptionally deep in the Java
2334 // hierarchy and we have to scan the secondary superclass list the hard way.
2335 // Worst-case type is a little odd: NULL is allowed as a result (usually
2336 // klass loads can never produce a NULL).
2337 Node *chk_off_X = ConvI2X(chk_off);
2338 Node *p2 = _gvn.transform( new (C) AddPNode(subklass,subklass,chk_off_X) );
2339 // For some types like interfaces the following loadKlass is from a 1-word
2340 // cache which is mutable so can't use immutable memory. Other
2341 // types load from the super-class display table which is immutable.
2342 Node *kmem = might_be_cache ? memory(p2) : immutable_memory();
2343 Node *nkls = _gvn.transform( LoadKlassNode::make( _gvn, kmem, p2, _gvn.type(p2)->is_ptr(), TypeKlassPtr::OBJECT_OR_NULL ) );
2344
2345 // Compile speed common case: ARE a subtype and we canNOT fail
2346 if( superklass == nkls )
2347 return top(); // false path is dead; no test needed.
2348
2349 // See if we get an immediate positive hit. Happens roughly 83% of the
2350 // time. Test to see if the value loaded just previously from the subklass
2351 // is exactly the superklass.
2352 Node *cmp1 = _gvn.transform( new (C) CmpPNode( superklass, nkls ) );
2353 Node *bol1 = _gvn.transform( new (C) BoolNode( cmp1, BoolTest::eq ) );
2354 IfNode *iff1 = create_and_xform_if( control(), bol1, PROB_LIKELY(0.83f), COUNT_UNKNOWN );
2355 Node *iftrue1 = _gvn.transform( new (C) IfTrueNode ( iff1 ) );
2356 set_control( _gvn.transform( new (C) IfFalseNode( iff1 ) ) );
2357
2358 // Compile speed common case: Check for being deterministic right now. If
2359 // chk_off is a constant and not equal to cacheoff then we are NOT a
2360 // subklass. In this case we need exactly the 1 test above and we can
2361 // return those results immediately.
2362 if (!might_be_cache) {
2363 Node* not_subtype_ctrl = control();
2364 set_control(iftrue1); // We need exactly the 1 test above
2365 return not_subtype_ctrl;
2366 }
2367
2368 // Gather the various success & failures here
2369 RegionNode *r_ok_subtype = new (C) RegionNode(4);
2370 record_for_igvn(r_ok_subtype);
2371 RegionNode *r_not_subtype = new (C) RegionNode(3);
2372 record_for_igvn(r_not_subtype);
2373
2374 r_ok_subtype->init_req(1, iftrue1);
2375
2376 // Check for immediate negative hit. Happens roughly 11% of the time (which
2377 // is roughly 63% of the remaining cases). Test to see if the loaded
2378 // check-offset points into the subklass display list or the 1-element
2379 // cache. If it points to the display (and NOT the cache) and the display
2380 // missed then it's not a subtype.
2381 Node *cacheoff = _gvn.intcon(cacheoff_con);
2382 Node *cmp2 = _gvn.transform( new (C) CmpINode( chk_off, cacheoff ) );
2383 Node *bol2 = _gvn.transform( new (C) BoolNode( cmp2, BoolTest::ne ) );
2384 IfNode *iff2 = create_and_xform_if( control(), bol2, PROB_LIKELY(0.63f), COUNT_UNKNOWN );
2385 r_not_subtype->init_req(1, _gvn.transform( new (C) IfTrueNode (iff2) ) );
2386 set_control( _gvn.transform( new (C) IfFalseNode(iff2) ) );
2387
2388 // Check for self. Very rare to get here, but it is taken 1/3 the time.
2389 // No performance impact (too rare) but allows sharing of secondary arrays
2390 // which has some footprint reduction.
2391 Node *cmp3 = _gvn.transform( new (C) CmpPNode( subklass, superklass ) );
2392 Node *bol3 = _gvn.transform( new (C) BoolNode( cmp3, BoolTest::eq ) );
2393 IfNode *iff3 = create_and_xform_if( control(), bol3, PROB_LIKELY(0.36f), COUNT_UNKNOWN );
2394 r_ok_subtype->init_req(2, _gvn.transform( new (C) IfTrueNode ( iff3 ) ) );
2395 set_control( _gvn.transform( new (C) IfFalseNode( iff3 ) ) );
2396
2397 // -- Roads not taken here: --
2398 // We could also have chosen to perform the self-check at the beginning
2399 // of this code sequence, as the assembler does. This would not pay off
2400 // the same way, since the optimizer, unlike the assembler, can perform
2401 // static type analysis to fold away many successful self-checks.
2402 // Non-foldable self checks work better here in second position, because
2403 // the initial primary superclass check subsumes a self-check for most
2404 // types. An exception would be a secondary type like array-of-interface,
2405 // which does not appear in its own primary supertype display.
2406 // Finally, we could have chosen to move the self-check into the
2407 // PartialSubtypeCheckNode, and from there out-of-line in a platform
2408 // dependent manner. But it is worthwhile to have the check here,
2409 // where it can be perhaps be optimized. The cost in code space is
2410 // small (register compare, branch).
2411
2412 // Now do a linear scan of the secondary super-klass array. Again, no real
2413 // performance impact (too rare) but it's gotta be done.
2414 // Since the code is rarely used, there is no penalty for moving it
2415 // out of line, and it can only improve I-cache density.
2416 // The decision to inline or out-of-line this final check is platform
2417 // dependent, and is found in the AD file definition of PartialSubtypeCheck.
2418 Node* psc = _gvn.transform(
2419 new (C) PartialSubtypeCheckNode(control(), subklass, superklass) );
2420
2421 Node *cmp4 = _gvn.transform( new (C) CmpPNode( psc, null() ) );
2422 Node *bol4 = _gvn.transform( new (C) BoolNode( cmp4, BoolTest::ne ) );
2423 IfNode *iff4 = create_and_xform_if( control(), bol4, PROB_FAIR, COUNT_UNKNOWN );
2424 r_not_subtype->init_req(2, _gvn.transform( new (C) IfTrueNode (iff4) ) );
2425 r_ok_subtype ->init_req(3, _gvn.transform( new (C) IfFalseNode(iff4) ) );
2426
2427 // Return false path; set default control to true path.
2428 set_control( _gvn.transform(r_ok_subtype) );
2429 return _gvn.transform(r_not_subtype);
2430 }
2431
2432 //----------------------------static_subtype_check-----------------------------
2433 // Shortcut important common cases when superklass is exact:
2434 // (0) superklass is java.lang.Object (can occur in reflective code)
2435 // (1) subklass is already limited to a subtype of superklass => always ok
2436 // (2) subklass does not overlap with superklass => always fail
2437 // (3) superklass has NO subtypes and we can check with a simple compare.
2438 int GraphKit::static_subtype_check(ciKlass* superk, ciKlass* subk) {
2439 if (StressReflectiveCode) {
2440 return SSC_full_test; // Let caller generate the general case.
2441 }
2442
2443 if (superk == env()->Object_klass()) {
2444 return SSC_always_true; // (0) this test cannot fail
2445 }
2446
2447 ciType* superelem = superk;
2448 if (superelem->is_array_klass())
2449 superelem = superelem->as_array_klass()->base_element_type();
2450
2451 if (!subk->is_interface()) { // cannot trust static interface types yet
2452 if (subk->is_subtype_of(superk)) {
2453 return SSC_always_true; // (1) false path dead; no dynamic test needed
2454 }
2455 if (!(superelem->is_klass() && superelem->as_klass()->is_interface()) &&
2456 !superk->is_subtype_of(subk)) {
2457 return SSC_always_false;
2458 }
2459 }
2460
2461 // If casting to an instance klass, it must have no subtypes
2462 if (superk->is_interface()) {
2463 // Cannot trust interfaces yet.
2464 // %%% S.B. superk->nof_implementors() == 1
2465 } else if (superelem->is_instance_klass()) {
2466 ciInstanceKlass* ik = superelem->as_instance_klass();
2467 if (!ik->has_subklass() && !ik->is_interface()) {
2468 if (!ik->is_final()) {
2469 // Add a dependency if there is a chance of a later subclass.
2470 C->dependencies()->assert_leaf_type(ik);
2471 }
2472 return SSC_easy_test; // (3) caller can do a simple ptr comparison
2473 }
2474 } else {
2475 // A primitive array type has no subtypes.
2476 return SSC_easy_test; // (3) caller can do a simple ptr comparison
2477 }
2478
2479 return SSC_full_test;
2480 }
2481
2482 // Profile-driven exact type check:
2483 Node* GraphKit::type_check_receiver(Node* receiver, ciKlass* klass,
2484 float prob,
2485 Node* *casted_receiver) {
2486 const TypeKlassPtr* tklass = TypeKlassPtr::make(klass);
2487 Node* recv_klass = load_object_klass(receiver);
2488 Node* want_klass = makecon(tklass);
2489 Node* cmp = _gvn.transform( new(C) CmpPNode(recv_klass, want_klass) );
2490 Node* bol = _gvn.transform( new(C) BoolNode(cmp, BoolTest::eq) );
2491 IfNode* iff = create_and_xform_if(control(), bol, prob, COUNT_UNKNOWN);
2492 set_control( _gvn.transform( new(C) IfTrueNode (iff) ));
2493 Node* fail = _gvn.transform( new(C) IfFalseNode(iff) );
2494
2495 const TypeOopPtr* recv_xtype = tklass->as_instance_type();
2496 assert(recv_xtype->klass_is_exact(), "");
2497
2498 // Subsume downstream occurrences of receiver with a cast to
2499 // recv_xtype, since now we know what the type will be.
2500 Node* cast = new(C) CheckCastPPNode(control(), receiver, recv_xtype);
2501 (*casted_receiver) = _gvn.transform(cast);
2502 // (User must make the replace_in_map call.)
2503
2504 return fail;
2505 }
2506
2507
2508 //------------------------------seems_never_null-------------------------------
2509 // Use null_seen information if it is available from the profile.
2510 // If we see an unexpected null at a type check we record it and force a
2511 // recompile; the offending check will be recompiled to handle NULLs.
2512 // If we see several offending BCIs, then all checks in the
2513 // method will be recompiled.
2514 bool GraphKit::seems_never_null(Node* obj, ciProfileData* data) {
2515 if (UncommonNullCast // Cutout for this technique
2516 && obj != null() // And not the -Xcomp stupid case?
2517 && !too_many_traps(Deoptimization::Reason_null_check)
2518 ) {
2519 if (data == NULL)
2520 // Edge case: no mature data. Be optimistic here.
2521 return true;
2522 // If the profile has not seen a null, assume it won't happen.
2523 assert(java_bc() == Bytecodes::_checkcast ||
2524 java_bc() == Bytecodes::_instanceof ||
2525 java_bc() == Bytecodes::_aastore, "MDO must collect null_seen bit here");
2526 return !data->as_BitData()->null_seen();
2527 }
2528 return false;
2529 }
2530
2531 //------------------------maybe_cast_profiled_receiver-------------------------
2532 // If the profile has seen exactly one type, narrow to exactly that type.
2533 // Subsequent type checks will always fold up.
2534 Node* GraphKit::maybe_cast_profiled_receiver(Node* not_null_obj,
2535 ciProfileData* data,
2536 ciKlass* require_klass) {
2537 if (!UseTypeProfile || !TypeProfileCasts) return NULL;
2538 if (data == NULL) return NULL;
2539
2540 // Make sure we haven't already deoptimized from this tactic.
2541 if (too_many_traps(Deoptimization::Reason_class_check))
2542 return NULL;
2543
2544 // (No, this isn't a call, but it's enough like a virtual call
2545 // to use the same ciMethod accessor to get the profile info...)
2546 ciCallProfile profile = method()->call_profile_at_bci(bci());
2547 if (profile.count() >= 0 && // no cast failures here
2548 profile.has_receiver(0) &&
2549 profile.morphism() == 1) {
2550 ciKlass* exact_kls = profile.receiver(0);
2551 if (require_klass == NULL ||
2552 static_subtype_check(require_klass, exact_kls) == SSC_always_true) {
2553 // If we narrow the type to match what the type profile sees,
2554 // we can then remove the rest of the cast.
2555 // This is a win, even if the exact_kls is very specific,
2556 // because downstream operations, such as method calls,
2557 // will often benefit from the sharper type.
2558 Node* exact_obj = not_null_obj; // will get updated in place...
2559 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0,
2560 &exact_obj);
2561 { PreserveJVMState pjvms(this);
2562 set_control(slow_ctl);
2563 uncommon_trap(Deoptimization::Reason_class_check,
2564 Deoptimization::Action_maybe_recompile);
2565 }
2566 replace_in_map(not_null_obj, exact_obj);
2567 return exact_obj;
2568 }
2569 // assert(ssc == SSC_always_true)... except maybe the profile lied to us.
2570 }
2571
2572 return NULL;
2573 }
2574
2575
2576 //-------------------------------gen_instanceof--------------------------------
2577 // Generate an instance-of idiom. Used by both the instance-of bytecode
2578 // and the reflective instance-of call.
2579 Node* GraphKit::gen_instanceof(Node* obj, Node* superklass) {
2580 kill_dead_locals(); // Benefit all the uncommon traps
2581 assert( !stopped(), "dead parse path should be checked in callers" );
2582 assert(!TypePtr::NULL_PTR->higher_equal(_gvn.type(superklass)->is_klassptr()),
2583 "must check for not-null not-dead klass in callers");
2584
2585 // Make the merge point
2586 enum { _obj_path = 1, _fail_path, _null_path, PATH_LIMIT };
2587 RegionNode* region = new(C) RegionNode(PATH_LIMIT);
2588 Node* phi = new(C) PhiNode(region, TypeInt::BOOL);
2589 C->set_has_split_ifs(true); // Has chance for split-if optimization
2590
2591 ciProfileData* data = NULL;
2592 if (java_bc() == Bytecodes::_instanceof) { // Only for the bytecode
2593 data = method()->method_data()->bci_to_data(bci());
2594 }
2595 bool never_see_null = (ProfileDynamicTypes // aggressive use of profile
2596 && seems_never_null(obj, data));
2597
2598 // Null check; get casted pointer; set region slot 3
2599 Node* null_ctl = top();
2600 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null);
2601
2602 // If not_null_obj is dead, only null-path is taken
2603 if (stopped()) { // Doing instance-of on a NULL?
2604 set_control(null_ctl);
2605 return intcon(0);
2606 }
2607 region->init_req(_null_path, null_ctl);
2608 phi ->init_req(_null_path, intcon(0)); // Set null path value
2609 if (null_ctl == top()) {
2610 // Do this eagerly, so that pattern matches like is_diamond_phi
2611 // will work even during parsing.
2612 assert(_null_path == PATH_LIMIT-1, "delete last");
2613 region->del_req(_null_path);
2614 phi ->del_req(_null_path);
2615 }
2616
2617 if (ProfileDynamicTypes && data != NULL) {
2618 Node* cast_obj = maybe_cast_profiled_receiver(not_null_obj, data, NULL);
2619 if (stopped()) { // Profile disagrees with this path.
2620 set_control(null_ctl); // Null is the only remaining possibility.
2621 return intcon(0);
2622 }
2623 if (cast_obj != NULL)
2624 not_null_obj = cast_obj;
2625 }
2626
2627 // Load the object's klass
2628 Node* obj_klass = load_object_klass(not_null_obj);
2629
2630 // Generate the subtype check
2631 Node* not_subtype_ctrl = gen_subtype_check(obj_klass, superklass);
2632
2633 // Plug in the success path to the general merge in slot 1.
2634 region->init_req(_obj_path, control());
2635 phi ->init_req(_obj_path, intcon(1));
2636
2637 // Plug in the failing path to the general merge in slot 2.
2638 region->init_req(_fail_path, not_subtype_ctrl);
2639 phi ->init_req(_fail_path, intcon(0));
2640
2641 // Return final merged results
2642 set_control( _gvn.transform(region) );
2643 record_for_igvn(region);
2644 return _gvn.transform(phi);
2645 }
2646
2647 //-------------------------------gen_checkcast---------------------------------
2648 // Generate a checkcast idiom. Used by both the checkcast bytecode and the
2649 // array store bytecode. Stack must be as-if BEFORE doing the bytecode so the
2650 // uncommon-trap paths work. Adjust stack after this call.
2651 // If failure_control is supplied and not null, it is filled in with
2652 // the control edge for the cast failure. Otherwise, an appropriate
2653 // uncommon trap or exception is thrown.
2654 Node* GraphKit::gen_checkcast(Node *obj, Node* superklass,
2655 Node* *failure_control) {
2656 kill_dead_locals(); // Benefit all the uncommon traps
2657 const TypeKlassPtr *tk = _gvn.type(superklass)->is_klassptr();
2658 const Type *toop = TypeOopPtr::make_from_klass(tk->klass());
2659
2660 // Fast cutout: Check the case that the cast is vacuously true.
2661 // This detects the common cases where the test will short-circuit
2662 // away completely. We do this before we perform the null check,
2663 // because if the test is going to turn into zero code, we don't
2664 // want a residual null check left around. (Causes a slowdown,
2665 // for example, in some objArray manipulations, such as a[i]=a[j].)
2666 if (tk->singleton()) {
2667 const TypeOopPtr* objtp = _gvn.type(obj)->isa_oopptr();
2668 if (objtp != NULL && objtp->klass() != NULL) {
2669 switch (static_subtype_check(tk->klass(), objtp->klass())) {
2670 case SSC_always_true:
2671 return obj;
2672 case SSC_always_false:
2673 // It needs a null check because a null will *pass* the cast check.
2674 // A non-null value will always produce an exception.
2675 return null_assert(obj);
2676 }
2677 }
2678 }
2679
2680 ciProfileData* data = NULL;
2681 if (failure_control == NULL) { // use MDO in regular case only
2682 assert(java_bc() == Bytecodes::_aastore ||
2683 java_bc() == Bytecodes::_checkcast,
2684 "interpreter profiles type checks only for these BCs");
2685 data = method()->method_data()->bci_to_data(bci());
2686 }
2687
2688 // Make the merge point
2689 enum { _obj_path = 1, _null_path, PATH_LIMIT };
2690 RegionNode* region = new (C) RegionNode(PATH_LIMIT);
2691 Node* phi = new (C) PhiNode(region, toop);
2692 C->set_has_split_ifs(true); // Has chance for split-if optimization
2693
2694 // Use null-cast information if it is available
2695 bool never_see_null = ((failure_control == NULL) // regular case only
2696 && seems_never_null(obj, data));
2697
2698 // Null check; get casted pointer; set region slot 3
2699 Node* null_ctl = top();
2700 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null);
2701
2702 // If not_null_obj is dead, only null-path is taken
2703 if (stopped()) { // Doing instance-of on a NULL?
2704 set_control(null_ctl);
2705 return null();
2706 }
2707 region->init_req(_null_path, null_ctl);
2708 phi ->init_req(_null_path, null()); // Set null path value
2709 if (null_ctl == top()) {
2710 // Do this eagerly, so that pattern matches like is_diamond_phi
2711 // will work even during parsing.
2712 assert(_null_path == PATH_LIMIT-1, "delete last");
2713 region->del_req(_null_path);
2714 phi ->del_req(_null_path);
2715 }
2716
2717 Node* cast_obj = NULL;
2718 if (data != NULL &&
2719 // Counter has never been decremented (due to cast failure).
2720 // ...This is a reasonable thing to expect. It is true of
2721 // all casts inserted by javac to implement generic types.
2722 data->as_CounterData()->count() >= 0) {
2723 cast_obj = maybe_cast_profiled_receiver(not_null_obj, data, tk->klass());
2724 if (cast_obj != NULL) {
2725 if (failure_control != NULL) // failure is now impossible
2726 (*failure_control) = top();
2727 // adjust the type of the phi to the exact klass:
2728 phi->raise_bottom_type(_gvn.type(cast_obj)->meet(TypePtr::NULL_PTR));
2729 }
2730 }
2731
2732 if (cast_obj == NULL) {
2733 // Load the object's klass
2734 Node* obj_klass = load_object_klass(not_null_obj);
2735
2736 // Generate the subtype check
2737 Node* not_subtype_ctrl = gen_subtype_check( obj_klass, superklass );
2738
2739 // Plug in success path into the merge
2740 cast_obj = _gvn.transform(new (C) CheckCastPPNode(control(),
2741 not_null_obj, toop));
2742 // Failure path ends in uncommon trap (or may be dead - failure impossible)
2743 if (failure_control == NULL) {
2744 if (not_subtype_ctrl != top()) { // If failure is possible
2745 PreserveJVMState pjvms(this);
2746 set_control(not_subtype_ctrl);
2747 builtin_throw(Deoptimization::Reason_class_check, obj_klass);
2748 }
2749 } else {
2750 (*failure_control) = not_subtype_ctrl;
2751 }
2752 }
2753
2754 region->init_req(_obj_path, control());
2755 phi ->init_req(_obj_path, cast_obj);
2756
2757 // A merge of NULL or Casted-NotNull obj
2758 Node* res = _gvn.transform(phi);
2759
2760 // Note I do NOT always 'replace_in_map(obj,result)' here.
2761 // if( tk->klass()->can_be_primary_super() )
2762 // This means that if I successfully store an Object into an array-of-String
2763 // I 'forget' that the Object is really now known to be a String. I have to
2764 // do this because we don't have true union types for interfaces - if I store
2765 // a Baz into an array-of-Interface and then tell the optimizer it's an
2766 // Interface, I forget that it's also a Baz and cannot do Baz-like field
2767 // references to it. FIX THIS WHEN UNION TYPES APPEAR!
2768 // replace_in_map( obj, res );
2769
2770 // Return final merged results
2771 set_control( _gvn.transform(region) );
2772 record_for_igvn(region);
2773 return res;
2774 }
2775
2776 //------------------------------next_monitor-----------------------------------
2777 // What number should be given to the next monitor?
2778 int GraphKit::next_monitor() {
2779 int current = jvms()->monitor_depth()* C->sync_stack_slots();
2780 int next = current + C->sync_stack_slots();
2781 // Keep the toplevel high water mark current:
2782 if (C->fixed_slots() < next) C->set_fixed_slots(next);
2783 return current;
2784 }
2785
2786 //------------------------------insert_mem_bar---------------------------------
2787 // Memory barrier to avoid floating things around
2788 // The membar serves as a pinch point between both control and all memory slices.
2789 Node* GraphKit::insert_mem_bar(int opcode, Node* precedent) {
2790 MemBarNode* mb = MemBarNode::make(C, opcode, Compile::AliasIdxBot, precedent);
2791 mb->init_req(TypeFunc::Control, control());
2792 mb->init_req(TypeFunc::Memory, reset_memory());
2793 Node* membar = _gvn.transform(mb);
2794 set_control(_gvn.transform(new (C) ProjNode(membar, TypeFunc::Control)));
2795 set_all_memory_call(membar);
2796 return membar;
2797 }
2798
2799 //-------------------------insert_mem_bar_volatile----------------------------
2800 // Memory barrier to avoid floating things around
2801 // The membar serves as a pinch point between both control and memory(alias_idx).
2802 // If you want to make a pinch point on all memory slices, do not use this
2803 // function (even with AliasIdxBot); use insert_mem_bar() instead.
2804 Node* GraphKit::insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent) {
2805 // When Parse::do_put_xxx updates a volatile field, it appends a series
2806 // of MemBarVolatile nodes, one for *each* volatile field alias category.
2807 // The first membar is on the same memory slice as the field store opcode.
2808 // This forces the membar to follow the store. (Bug 6500685 broke this.)
2809 // All the other membars (for other volatile slices, including AliasIdxBot,
2810 // which stands for all unknown volatile slices) are control-dependent
2811 // on the first membar. This prevents later volatile loads or stores
2812 // from sliding up past the just-emitted store.
2813
2814 MemBarNode* mb = MemBarNode::make(C, opcode, alias_idx, precedent);
2815 mb->set_req(TypeFunc::Control,control());
2816 if (alias_idx == Compile::AliasIdxBot) {
2817 mb->set_req(TypeFunc::Memory, merged_memory()->base_memory());
2818 } else {
2819 assert(!(opcode == Op_Initialize && alias_idx != Compile::AliasIdxRaw), "fix caller");
2820 mb->set_req(TypeFunc::Memory, memory(alias_idx));
2821 }
2822 Node* membar = _gvn.transform(mb);
2823 set_control(_gvn.transform(new (C) ProjNode(membar, TypeFunc::Control)));
2824 if (alias_idx == Compile::AliasIdxBot) {
2825 merged_memory()->set_base_memory(_gvn.transform(new (C) ProjNode(membar, TypeFunc::Memory)));
2826 } else {
2827 set_memory(_gvn.transform(new (C) ProjNode(membar, TypeFunc::Memory)),alias_idx);
2828 }
2829 return membar;
2830 }
2831
2832 //------------------------------shared_lock------------------------------------
2833 // Emit locking code.
2834 FastLockNode* GraphKit::shared_lock(Node* obj) {
2835 // bci is either a monitorenter bc or InvocationEntryBci
2836 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
2837 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
2838
2839 if( !GenerateSynchronizationCode )
2840 return NULL; // Not locking things?
2841 if (stopped()) // Dead monitor?
2842 return NULL;
2843
2844 assert(dead_locals_are_killed(), "should kill locals before sync. point");
2845
2846 // Box the stack location
2847 Node* box = _gvn.transform(new (C) BoxLockNode(next_monitor()));
2848 Node* mem = reset_memory();
2849
2850 FastLockNode * flock = _gvn.transform(new (C) FastLockNode(0, obj, box) )->as_FastLock();
2851 if (PrintPreciseBiasedLockingStatistics) {
2852 // Create the counters for this fast lock.
2853 flock->create_lock_counter(sync_jvms()); // sync_jvms used to get current bci
2854 }
2855 // Add monitor to debug info for the slow path. If we block inside the
2856 // slow path and de-opt, we need the monitor hanging around
2857 map()->push_monitor( flock );
2858
2859 const TypeFunc *tf = LockNode::lock_type();
2860 LockNode *lock = new (C) LockNode(C, tf);
2861
2862 lock->init_req( TypeFunc::Control, control() );
2863 lock->init_req( TypeFunc::Memory , mem );
2864 lock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
2865 lock->init_req( TypeFunc::FramePtr, frameptr() );
2866 lock->init_req( TypeFunc::ReturnAdr, top() );
2867
2868 lock->init_req(TypeFunc::Parms + 0, obj);
2869 lock->init_req(TypeFunc::Parms + 1, box);
2870 lock->init_req(TypeFunc::Parms + 2, flock);
2871 add_safepoint_edges(lock);
2872
2873 lock = _gvn.transform( lock )->as_Lock();
2874
2875 // lock has no side-effects, sets few values
2876 set_predefined_output_for_runtime_call(lock, mem, TypeRawPtr::BOTTOM);
2877
2878 insert_mem_bar(Op_MemBarAcquireLock);
2879
2880 // Add this to the worklist so that the lock can be eliminated
2881 record_for_igvn(lock);
2882
2883 #ifndef PRODUCT
2884 if (PrintLockStatistics) {
2885 // Update the counter for this lock. Don't bother using an atomic
2886 // operation since we don't require absolute accuracy.
2887 lock->create_lock_counter(map()->jvms());
2888 increment_counter(lock->counter()->addr());
2889 }
2890 #endif
2891
2892 return flock;
2893 }
2894
2895
2896 //------------------------------shared_unlock----------------------------------
2897 // Emit unlocking code.
2898 void GraphKit::shared_unlock(Node* box, Node* obj) {
2899 // bci is either a monitorenter bc or InvocationEntryBci
2900 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
2901 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
2902
2903 if( !GenerateSynchronizationCode )
2904 return;
2905 if (stopped()) { // Dead monitor?
2906 map()->pop_monitor(); // Kill monitor from debug info
2907 return;
2908 }
2909
2910 // Memory barrier to avoid floating things down past the locked region
2911 insert_mem_bar(Op_MemBarReleaseLock);
2912
2913 const TypeFunc *tf = OptoRuntime::complete_monitor_exit_Type();
2914 UnlockNode *unlock = new (C) UnlockNode(C, tf);
2915 uint raw_idx = Compile::AliasIdxRaw;
2916 unlock->init_req( TypeFunc::Control, control() );
2917 unlock->init_req( TypeFunc::Memory , memory(raw_idx) );
2918 unlock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
2919 unlock->init_req( TypeFunc::FramePtr, frameptr() );
2920 unlock->init_req( TypeFunc::ReturnAdr, top() );
2921
2922 unlock->init_req(TypeFunc::Parms + 0, obj);
2923 unlock->init_req(TypeFunc::Parms + 1, box);
2924 unlock = _gvn.transform(unlock)->as_Unlock();
2925
2926 Node* mem = reset_memory();
2927
2928 // unlock has no side-effects, sets few values
2929 set_predefined_output_for_runtime_call(unlock, mem, TypeRawPtr::BOTTOM);
2930
2931 // Kill monitor from debug info
2932 map()->pop_monitor( );
2933 }
2934
2935 //-------------------------------get_layout_helper-----------------------------
2936 // If the given klass is a constant or known to be an array,
2937 // fetch the constant layout helper value into constant_value
2938 // and return (Node*)NULL. Otherwise, load the non-constant
2939 // layout helper value, and return the node which represents it.
2940 // This two-faced routine is useful because allocation sites
2941 // almost always feature constant types.
2942 Node* GraphKit::get_layout_helper(Node* klass_node, jint& constant_value) {
2943 const TypeKlassPtr* inst_klass = _gvn.type(klass_node)->isa_klassptr();
2944 if (!StressReflectiveCode && inst_klass != NULL) {
2945 ciKlass* klass = inst_klass->klass();
2946 bool xklass = inst_klass->klass_is_exact();
2947 if (xklass || klass->is_array_klass()) {
2948 jint lhelper = klass->layout_helper();
2949 if (lhelper != Klass::_lh_neutral_value) {
2950 constant_value = lhelper;
2951 return (Node*) NULL;
2952 }
2953 }
2954 }
2955 constant_value = Klass::_lh_neutral_value; // put in a known value
2956 Node* lhp = basic_plus_adr(klass_node, klass_node, in_bytes(Klass::layout_helper_offset()));
2957 return make_load(NULL, lhp, TypeInt::INT, T_INT);
2958 }
2959
2960 // We just put in an allocate/initialize with a big raw-memory effect.
2961 // Hook selected additional alias categories on the initialization.
2962 static void hook_memory_on_init(GraphKit& kit, int alias_idx,
2963 MergeMemNode* init_in_merge,
2964 Node* init_out_raw) {
2965 DEBUG_ONLY(Node* init_in_raw = init_in_merge->base_memory());
2966 assert(init_in_merge->memory_at(alias_idx) == init_in_raw, "");
2967
2968 Node* prevmem = kit.memory(alias_idx);
2969 init_in_merge->set_memory_at(alias_idx, prevmem);
2970 kit.set_memory(init_out_raw, alias_idx);
2971 }
2972
2973 //---------------------------set_output_for_allocation-------------------------
2974 Node* GraphKit::set_output_for_allocation(AllocateNode* alloc,
2975 const TypeOopPtr* oop_type) {
2976 int rawidx = Compile::AliasIdxRaw;
2977 alloc->set_req( TypeFunc::FramePtr, frameptr() );
2978 add_safepoint_edges(alloc);
2979 Node* allocx = _gvn.transform(alloc);
2980 set_control( _gvn.transform(new (C) ProjNode(allocx, TypeFunc::Control) ) );
2981 // create memory projection for i_o
2982 set_memory ( _gvn.transform( new (C) ProjNode(allocx, TypeFunc::Memory, true) ), rawidx );
2983 make_slow_call_ex(allocx, env()->OutOfMemoryError_klass(), true);
2984
2985 // create a memory projection as for the normal control path
2986 Node* malloc = _gvn.transform(new (C) ProjNode(allocx, TypeFunc::Memory));
2987 set_memory(malloc, rawidx);
2988
2989 // a normal slow-call doesn't change i_o, but an allocation does
2990 // we create a separate i_o projection for the normal control path
2991 set_i_o(_gvn.transform( new (C) ProjNode(allocx, TypeFunc::I_O, false) ) );
2992 Node* rawoop = _gvn.transform( new (C) ProjNode(allocx, TypeFunc::Parms) );
2993
2994 // put in an initialization barrier
2995 InitializeNode* init = insert_mem_bar_volatile(Op_Initialize, rawidx,
2996 rawoop)->as_Initialize();
2997 assert(alloc->initialization() == init, "2-way macro link must work");
2998 assert(init ->allocation() == alloc, "2-way macro link must work");
2999 {
3000 // Extract memory strands which may participate in the new object's
3001 // initialization, and source them from the new InitializeNode.
3002 // This will allow us to observe initializations when they occur,
3003 // and link them properly (as a group) to the InitializeNode.
3004 assert(init->in(InitializeNode::Memory) == malloc, "");
3005 MergeMemNode* minit_in = MergeMemNode::make(C, malloc);
3006 init->set_req(InitializeNode::Memory, minit_in);
3007 record_for_igvn(minit_in); // fold it up later, if possible
3008 Node* minit_out = memory(rawidx);
3009 assert(minit_out->is_Proj() && minit_out->in(0) == init, "");
3010 if (oop_type->isa_aryptr()) {
3011 const TypePtr* telemref = oop_type->add_offset(Type::OffsetBot);
3012 int elemidx = C->get_alias_index(telemref);
3013 hook_memory_on_init(*this, elemidx, minit_in, minit_out);
3014 } else if (oop_type->isa_instptr()) {
3015 ciInstanceKlass* ik = oop_type->klass()->as_instance_klass();
3016 for (int i = 0, len = ik->nof_nonstatic_fields(); i < len; i++) {
3017 ciField* field = ik->nonstatic_field_at(i);
3018 if (field->offset() >= TrackedInitializationLimit * HeapWordSize)
3019 continue; // do not bother to track really large numbers of fields
3020 // Find (or create) the alias category for this field:
3021 int fieldidx = C->alias_type(field)->index();
3022 hook_memory_on_init(*this, fieldidx, minit_in, minit_out);
3023 }
3024 }
3025 }
3026
3027 // Cast raw oop to the real thing...
3028 Node* javaoop = new (C) CheckCastPPNode(control(), rawoop, oop_type);
3029 javaoop = _gvn.transform(javaoop);
3030 C->set_recent_alloc(control(), javaoop);
3031 assert(just_allocated_object(control()) == javaoop, "just allocated");
3032
3033 #ifdef ASSERT
3034 { // Verify that the AllocateNode::Ideal_allocation recognizers work:
3035 assert(AllocateNode::Ideal_allocation(rawoop, &_gvn) == alloc,
3036 "Ideal_allocation works");
3037 assert(AllocateNode::Ideal_allocation(javaoop, &_gvn) == alloc,
3038 "Ideal_allocation works");
3039 if (alloc->is_AllocateArray()) {
3040 assert(AllocateArrayNode::Ideal_array_allocation(rawoop, &_gvn) == alloc->as_AllocateArray(),
3041 "Ideal_allocation works");
3042 assert(AllocateArrayNode::Ideal_array_allocation(javaoop, &_gvn) == alloc->as_AllocateArray(),
3043 "Ideal_allocation works");
3044 } else {
3045 assert(alloc->in(AllocateNode::ALength)->is_top(), "no length, please");
3046 }
3047 }
3048 #endif //ASSERT
3049
3050 return javaoop;
3051 }
3052
3053 //---------------------------new_instance--------------------------------------
3054 // This routine takes a klass_node which may be constant (for a static type)
3055 // or may be non-constant (for reflective code). It will work equally well
3056 // for either, and the graph will fold nicely if the optimizer later reduces
3057 // the type to a constant.
3058 // The optional arguments are for specialized use by intrinsics:
3059 // - If 'extra_slow_test' if not null is an extra condition for the slow-path.
3060 // - If 'return_size_val', report the the total object size to the caller.
3061 Node* GraphKit::new_instance(Node* klass_node,
3062 Node* extra_slow_test,
3063 Node* *return_size_val) {
3064 // Compute size in doublewords
3065 // The size is always an integral number of doublewords, represented
3066 // as a positive bytewise size stored in the klass's layout_helper.
3067 // The layout_helper also encodes (in a low bit) the need for a slow path.
3068 jint layout_con = Klass::_lh_neutral_value;
3069 Node* layout_val = get_layout_helper(klass_node, layout_con);
3070 int layout_is_con = (layout_val == NULL);
3071
3072 if (extra_slow_test == NULL) extra_slow_test = intcon(0);
3073 // Generate the initial go-slow test. It's either ALWAYS (return a
3074 // Node for 1) or NEVER (return a NULL) or perhaps (in the reflective
3075 // case) a computed value derived from the layout_helper.
3076 Node* initial_slow_test = NULL;
3077 if (layout_is_con) {
3078 assert(!StressReflectiveCode, "stress mode does not use these paths");
3079 bool must_go_slow = Klass::layout_helper_needs_slow_path(layout_con);
3080 initial_slow_test = must_go_slow? intcon(1): extra_slow_test;
3081
3082 } else { // reflective case
3083 // This reflective path is used by Unsafe.allocateInstance.
3084 // (It may be stress-tested by specifying StressReflectiveCode.)
3085 // Basically, we want to get into the VM is there's an illegal argument.
3086 Node* bit = intcon(Klass::_lh_instance_slow_path_bit);
3087 initial_slow_test = _gvn.transform( new (C) AndINode(layout_val, bit) );
3088 if (extra_slow_test != intcon(0)) {
3089 initial_slow_test = _gvn.transform( new (C) OrINode(initial_slow_test, extra_slow_test) );
3090 }
3091 // (Macro-expander will further convert this to a Bool, if necessary.)
3092 }
3093
3094 // Find the size in bytes. This is easy; it's the layout_helper.
3095 // The size value must be valid even if the slow path is taken.
3096 Node* size = NULL;
3097 if (layout_is_con) {
3098 size = MakeConX(Klass::layout_helper_size_in_bytes(layout_con));
3099 } else { // reflective case
3100 // This reflective path is used by clone and Unsafe.allocateInstance.
3101 size = ConvI2X(layout_val);
3102
3103 // Clear the low bits to extract layout_helper_size_in_bytes:
3104 assert((int)Klass::_lh_instance_slow_path_bit < BytesPerLong, "clear bit");
3105 Node* mask = MakeConX(~ (intptr_t)right_n_bits(LogBytesPerLong));
3106 size = _gvn.transform( new (C) AndXNode(size, mask) );
3107 }
3108 if (return_size_val != NULL) {
3109 (*return_size_val) = size;
3110 }
3111
3112 // This is a precise notnull oop of the klass.
3113 // (Actually, it need not be precise if this is a reflective allocation.)
3114 // It's what we cast the result to.
3115 const TypeKlassPtr* tklass = _gvn.type(klass_node)->isa_klassptr();
3116 if (!tklass) tklass = TypeKlassPtr::OBJECT;
3117 const TypeOopPtr* oop_type = tklass->as_instance_type();
3118
3119 // Now generate allocation code
3120
3121 // The entire memory state is needed for slow path of the allocation
3122 // since GC and deoptimization can happened.
3123 Node *mem = reset_memory();
3124 set_all_memory(mem); // Create new memory state
3125
3126 AllocateNode* alloc
3127 = new (C) AllocateNode(C, AllocateNode::alloc_type(),
3128 control(), mem, i_o(),
3129 size, klass_node,
3130 initial_slow_test);
3131
3132 return set_output_for_allocation(alloc, oop_type);
3133 }
3134
3135 //-------------------------------new_array-------------------------------------
3136 // helper for both newarray and anewarray
3137 // The 'length' parameter is (obviously) the length of the array.
3138 // See comments on new_instance for the meaning of the other arguments.
3139 Node* GraphKit::new_array(Node* klass_node, // array klass (maybe variable)
3140 Node* length, // number of array elements
3141 int nargs, // number of arguments to push back for uncommon trap
3142 Node* *return_size_val) {
3143 jint layout_con = Klass::_lh_neutral_value;
3144 Node* layout_val = get_layout_helper(klass_node, layout_con);
3145 int layout_is_con = (layout_val == NULL);
3146
3147 if (!layout_is_con && !StressReflectiveCode &&
3148 !too_many_traps(Deoptimization::Reason_class_check)) {
3149 // This is a reflective array creation site.
3150 // Optimistically assume that it is a subtype of Object[],
3151 // so that we can fold up all the address arithmetic.
3152 layout_con = Klass::array_layout_helper(T_OBJECT);
3153 Node* cmp_lh = _gvn.transform( new(C) CmpINode(layout_val, intcon(layout_con)) );
3154 Node* bol_lh = _gvn.transform( new(C) BoolNode(cmp_lh, BoolTest::eq) );
3155 { BuildCutout unless(this, bol_lh, PROB_MAX);
3156 inc_sp(nargs);
3157 uncommon_trap(Deoptimization::Reason_class_check,
3158 Deoptimization::Action_maybe_recompile);
3159 }
3160 layout_val = NULL;
3161 layout_is_con = true;
3162 }
3163
3164 // Generate the initial go-slow test. Make sure we do not overflow
3165 // if length is huge (near 2Gig) or negative! We do not need
3166 // exact double-words here, just a close approximation of needed
3167 // double-words. We can't add any offset or rounding bits, lest we
3168 // take a size -1 of bytes and make it positive. Use an unsigned
3169 // compare, so negative sizes look hugely positive.
3170 int fast_size_limit = FastAllocateSizeLimit;
3171 if (layout_is_con) {
3172 assert(!StressReflectiveCode, "stress mode does not use these paths");
3173 // Increase the size limit if we have exact knowledge of array type.
3174 int log2_esize = Klass::layout_helper_log2_element_size(layout_con);
3175 fast_size_limit <<= (LogBytesPerLong - log2_esize);
3176 }
3177
3178 Node* initial_slow_cmp = _gvn.transform( new (C) CmpUNode( length, intcon( fast_size_limit ) ) );
3179 Node* initial_slow_test = _gvn.transform( new (C) BoolNode( initial_slow_cmp, BoolTest::gt ) );
3180 if (initial_slow_test->is_Bool()) {
3181 // Hide it behind a CMoveI, or else PhaseIdealLoop::split_up will get sick.
3182 initial_slow_test = initial_slow_test->as_Bool()->as_int_value(&_gvn);
3183 }
3184
3185 // --- Size Computation ---
3186 // array_size = round_to_heap(array_header + (length << elem_shift));
3187 // where round_to_heap(x) == round_to(x, MinObjAlignmentInBytes)
3188 // and round_to(x, y) == ((x + y-1) & ~(y-1))
3189 // The rounding mask is strength-reduced, if possible.
3190 int round_mask = MinObjAlignmentInBytes - 1;
3191 Node* header_size = NULL;
3192 int header_size_min = arrayOopDesc::base_offset_in_bytes(T_BYTE);
3193 // (T_BYTE has the weakest alignment and size restrictions...)
3194 if (layout_is_con) {
3195 int hsize = Klass::layout_helper_header_size(layout_con);
3196 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3197 BasicType etype = Klass::layout_helper_element_type(layout_con);
3198 if ((round_mask & ~right_n_bits(eshift)) == 0)
3199 round_mask = 0; // strength-reduce it if it goes away completely
3200 assert((hsize & right_n_bits(eshift)) == 0, "hsize is pre-rounded");
3201 assert(header_size_min <= hsize, "generic minimum is smallest");
3202 header_size_min = hsize;
3203 header_size = intcon(hsize + round_mask);
3204 } else {
3205 Node* hss = intcon(Klass::_lh_header_size_shift);
3206 Node* hsm = intcon(Klass::_lh_header_size_mask);
3207 Node* hsize = _gvn.transform( new(C) URShiftINode(layout_val, hss) );
3208 hsize = _gvn.transform( new(C) AndINode(hsize, hsm) );
3209 Node* mask = intcon(round_mask);
3210 header_size = _gvn.transform( new(C) AddINode(hsize, mask) );
3211 }
3212
3213 Node* elem_shift = NULL;
3214 if (layout_is_con) {
3215 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3216 if (eshift != 0)
3217 elem_shift = intcon(eshift);
3218 } else {
3219 // There is no need to mask or shift this value.
3220 // The semantics of LShiftINode include an implicit mask to 0x1F.
3221 assert(Klass::_lh_log2_element_size_shift == 0, "use shift in place");
3222 elem_shift = layout_val;
3223 }
3224
3225 // Transition to native address size for all offset calculations:
3226 Node* lengthx = ConvI2X(length);
3227 Node* headerx = ConvI2X(header_size);
3228 #ifdef _LP64
3229 { const TypeLong* tllen = _gvn.find_long_type(lengthx);
3230 if (tllen != NULL && tllen->_lo < 0) {
3231 // Add a manual constraint to a positive range. Cf. array_element_address.
3232 jlong size_max = arrayOopDesc::max_array_length(T_BYTE);
3233 if (size_max > tllen->_hi) size_max = tllen->_hi;
3234 const TypeLong* tlcon = TypeLong::make(CONST64(0), size_max, Type::WidenMin);
3235 lengthx = _gvn.transform( new (C) ConvI2LNode(length, tlcon));
3236 }
3237 }
3238 #endif
3239
3240 // Combine header size (plus rounding) and body size. Then round down.
3241 // This computation cannot overflow, because it is used only in two
3242 // places, one where the length is sharply limited, and the other
3243 // after a successful allocation.
3244 Node* abody = lengthx;
3245 if (elem_shift != NULL)
3246 abody = _gvn.transform( new(C) LShiftXNode(lengthx, elem_shift) );
3247 Node* size = _gvn.transform( new(C) AddXNode(headerx, abody) );
3248 if (round_mask != 0) {
3249 Node* mask = MakeConX(~round_mask);
3250 size = _gvn.transform( new(C) AndXNode(size, mask) );
3251 }
3252 // else if round_mask == 0, the size computation is self-rounding
3253
3254 if (return_size_val != NULL) {
3255 // This is the size
3256 (*return_size_val) = size;
3257 }
3258
3259 // Now generate allocation code
3260
3261 // The entire memory state is needed for slow path of the allocation
3262 // since GC and deoptimization can happened.
3263 Node *mem = reset_memory();
3264 set_all_memory(mem); // Create new memory state
3265
3266 // Create the AllocateArrayNode and its result projections
3267 AllocateArrayNode* alloc
3268 = new (C) AllocateArrayNode(C, AllocateArrayNode::alloc_type(),
3269 control(), mem, i_o(),
3270 size, klass_node,
3271 initial_slow_test,
3272 length);
3273
3274 // Cast to correct type. Note that the klass_node may be constant or not,
3275 // and in the latter case the actual array type will be inexact also.
3276 // (This happens via a non-constant argument to inline_native_newArray.)
3277 // In any case, the value of klass_node provides the desired array type.
3278 const TypeInt* length_type = _gvn.find_int_type(length);
3279 const TypeOopPtr* ary_type = _gvn.type(klass_node)->is_klassptr()->as_instance_type();
3280 if (ary_type->isa_aryptr() && length_type != NULL) {
3281 // Try to get a better type than POS for the size
3282 ary_type = ary_type->is_aryptr()->cast_to_size(length_type);
3283 }
3284
3285 Node* javaoop = set_output_for_allocation(alloc, ary_type);
3286
3287 // Cast length on remaining path to be as narrow as possible
3288 if (map()->find_edge(length) >= 0) {
3289 Node* ccast = alloc->make_ideal_length(ary_type, &_gvn);
3290 if (ccast != length) {
3291 _gvn.set_type_bottom(ccast);
3292 record_for_igvn(ccast);
3293 replace_in_map(length, ccast);
3294 }
3295 }
3296
3297 return javaoop;
3298 }
3299
3300 // The following "Ideal_foo" functions are placed here because they recognize
3301 // the graph shapes created by the functions immediately above.
3302
3303 //---------------------------Ideal_allocation----------------------------------
3304 // Given an oop pointer or raw pointer, see if it feeds from an AllocateNode.
3305 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase) {
3306 if (ptr == NULL) { // reduce dumb test in callers
3307 return NULL;
3308 }
3309 if (ptr->is_CheckCastPP()) { // strip a raw-to-oop cast
3310 ptr = ptr->in(1);
3311 if (ptr == NULL) return NULL;
3312 }
3313 if (ptr->is_Proj()) {
3314 Node* allo = ptr->in(0);
3315 if (allo != NULL && allo->is_Allocate()) {
3316 return allo->as_Allocate();
3317 }
3318 }
3319 // Report failure to match.
3320 return NULL;
3321 }
3322
3323 // Fancy version which also strips off an offset (and reports it to caller).
3324 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase,
3325 intptr_t& offset) {
3326 Node* base = AddPNode::Ideal_base_and_offset(ptr, phase, offset);
3327 if (base == NULL) return NULL;
3328 return Ideal_allocation(base, phase);
3329 }
3330
3331 // Trace Initialize <- Proj[Parm] <- Allocate
3332 AllocateNode* InitializeNode::allocation() {
3333 Node* rawoop = in(InitializeNode::RawAddress);
3334 if (rawoop->is_Proj()) {
3335 Node* alloc = rawoop->in(0);
3336 if (alloc->is_Allocate()) {
3337 return alloc->as_Allocate();
3338 }
3339 }
3340 return NULL;
3341 }
3342
3343 // Trace Allocate -> Proj[Parm] -> Initialize
3344 InitializeNode* AllocateNode::initialization() {
3345 ProjNode* rawoop = proj_out(AllocateNode::RawAddress);
3346 if (rawoop == NULL) return NULL;
3347 for (DUIterator_Fast imax, i = rawoop->fast_outs(imax); i < imax; i++) {
3348 Node* init = rawoop->fast_out(i);
3349 if (init->is_Initialize()) {
3350 assert(init->as_Initialize()->allocation() == this, "2-way link");
3351 return init->as_Initialize();
3352 }
3353 }
3354 return NULL;
3355 }
3356
3357 // Trace Allocate -> Proj[Parm] -> MemBarStoreStore
3358 MemBarStoreStoreNode* AllocateNode::storestore() {
3359 ProjNode* rawoop = proj_out(AllocateNode::RawAddress);
3360 if (rawoop == NULL) return NULL;
3361 for (DUIterator_Fast imax, i = rawoop->fast_outs(imax); i < imax; i++) {
3362 Node* storestore = rawoop->fast_out(i);
3363 if (storestore->is_MemBarStoreStore()) {
3364 return storestore->as_MemBarStoreStore();
3365 }
3366 }
3367 return NULL;
3368 }
3369
3370 //----------------------------- loop predicates ---------------------------
3371
3372 //------------------------------add_predicate_impl----------------------------
3373 void GraphKit::add_predicate_impl(Deoptimization::DeoptReason reason, int nargs) {
3374 // Too many traps seen?
3375 if (too_many_traps(reason)) {
3376 #ifdef ASSERT
3377 if (TraceLoopPredicate) {
3378 int tc = C->trap_count(reason);
3379 tty->print("too many traps=%s tcount=%d in ",
3380 Deoptimization::trap_reason_name(reason), tc);
3381 method()->print(); // which method has too many predicate traps
3382 tty->cr();
3383 }
3384 #endif
3385 // We cannot afford to take more traps here,
3386 // do not generate predicate.
3387 return;
3388 }
3389
3390 Node *cont = _gvn.intcon(1);
3391 Node* opq = _gvn.transform(new (C) Opaque1Node(C, cont));
3392 Node *bol = _gvn.transform(new (C) Conv2BNode(opq));
3393 IfNode* iff = create_and_map_if(control(), bol, PROB_MAX, COUNT_UNKNOWN);
3394 Node* iffalse = _gvn.transform(new (C) IfFalseNode(iff));
3395 C->add_predicate_opaq(opq);
3396 {
3397 PreserveJVMState pjvms(this);
3398 set_control(iffalse);
3399 inc_sp(nargs);
3400 uncommon_trap(reason, Deoptimization::Action_maybe_recompile);
3401 }
3402 Node* iftrue = _gvn.transform(new (C) IfTrueNode(iff));
3403 set_control(iftrue);
3404 }
3405
3406 //------------------------------add_predicate---------------------------------
3407 void GraphKit::add_predicate(int nargs) {
3408 if (UseLoopPredicate) {
3409 add_predicate_impl(Deoptimization::Reason_predicate, nargs);
3410 }
3411 // loop's limit check predicate should be near the loop.
3412 if (LoopLimitCheck) {
3413 add_predicate_impl(Deoptimization::Reason_loop_limit_check, nargs);
3414 }
3415 }
3416
3417 //----------------------------- store barriers ----------------------------
3418 #define __ ideal.
3419
3420 void GraphKit::sync_kit(IdealKit& ideal) {
3421 set_all_memory(__ merged_memory());
3422 set_i_o(__ i_o());
3423 set_control(__ ctrl());
3424 }
3425
3426 void GraphKit::final_sync(IdealKit& ideal) {
3427 // Final sync IdealKit and graphKit.
3428 __ drain_delay_transform();
3429 sync_kit(ideal);
3430 }
3431
3432 // vanilla/CMS post barrier
3433 // Insert a write-barrier store. This is to let generational GC work; we have
3434 // to flag all oop-stores before the next GC point.
3435 void GraphKit::write_barrier_post(Node* oop_store,
3436 Node* obj,
3437 Node* adr,
3438 uint adr_idx,
3439 Node* val,
3440 bool use_precise) {
3441 // No store check needed if we're storing a NULL or an old object
3442 // (latter case is probably a string constant). The concurrent
3443 // mark sweep garbage collector, however, needs to have all nonNull
3444 // oop updates flagged via card-marks.
3445 if (val != NULL && val->is_Con()) {
3446 // must be either an oop or NULL
3447 const Type* t = val->bottom_type();
3448 if (t == TypePtr::NULL_PTR || t == Type::TOP)
3449 // stores of null never (?) need barriers
3450 return;
3451 }
3452
3453 if (use_ReduceInitialCardMarks()
3454 && obj == just_allocated_object(control())) {
3455 // We can skip marks on a freshly-allocated object in Eden.
3456 // Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
3457 // That routine informs GC to take appropriate compensating steps,
3458 // upon a slow-path allocation, so as to make this card-mark
3459 // elision safe.
3460 return;
3461 }
3462
3463 if (!use_precise) {
3464 // All card marks for a (non-array) instance are in one place:
3465 adr = obj;
3466 }
3467 // (Else it's an array (or unknown), and we want more precise card marks.)
3468 assert(adr != NULL, "");
3469
3470 IdealKit ideal(this, true);
3471
3472 // Convert the pointer to an int prior to doing math on it
3473 Node* cast = __ CastPX(__ ctrl(), adr);
3474
3475 // Divide by card size
3476 assert(Universe::heap()->barrier_set()->kind() == BarrierSet::CardTableModRef,
3477 "Only one we handle so far.");
3478 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
3479
3480 // Combine card table base and card offset
3481 Node* card_adr = __ AddP(__ top(), byte_map_base_node(), card_offset );
3482
3483 // Get the alias_index for raw card-mark memory
3484 int adr_type = Compile::AliasIdxRaw;
3485 Node* zero = __ ConI(0); // Dirty card value
3486 BasicType bt = T_BYTE;
3487
3488 if (UseCondCardMark) {
3489 // The classic GC reference write barrier is typically implemented
3490 // as a store into the global card mark table. Unfortunately
3491 // unconditional stores can result in false sharing and excessive
3492 // coherence traffic as well as false transactional aborts.
3493 // UseCondCardMark enables MP "polite" conditional card mark
3494 // stores. In theory we could relax the load from ctrl() to
3495 // no_ctrl, but that doesn't buy much latitude.
3496 Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, bt, adr_type);
3497 __ if_then(card_val, BoolTest::ne, zero);
3498 }
3499
3500 // Smash zero into card
3501 if( !UseConcMarkSweepGC ) {
3502 __ store(__ ctrl(), card_adr, zero, bt, adr_type);
3503 } else {
3504 // Specialized path for CM store barrier
3505 __ storeCM(__ ctrl(), card_adr, zero, oop_store, adr_idx, bt, adr_type);
3506 }
3507
3508 if (UseCondCardMark) {
3509 __ end_if();
3510 }
3511
3512 // Final sync IdealKit and GraphKit.
3513 final_sync(ideal);
3514 }
3515
3516 // G1 pre/post barriers
3517 void GraphKit::g1_write_barrier_pre(bool do_load,
3518 Node* obj,
3519 Node* adr,
3520 uint alias_idx,
3521 Node* val,
3522 const TypeOopPtr* val_type,
3523 Node* pre_val,
3524 BasicType bt) {
3525
3526 // Some sanity checks
3527 // Note: val is unused in this routine.
3528
3529 if (do_load) {
3530 // We need to generate the load of the previous value
3531 assert(obj != NULL, "must have a base");
3532 assert(adr != NULL, "where are loading from?");
3533 assert(pre_val == NULL, "loaded already?");
3534 assert(val_type != NULL, "need a type");
3535 } else {
3536 // In this case both val_type and alias_idx are unused.
3537 assert(pre_val != NULL, "must be loaded already");
3538 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
3539 }
3540 assert(bt == T_OBJECT, "or we shouldn't be here");
3541
3542 IdealKit ideal(this, true);
3543
3544 Node* tls = __ thread(); // ThreadLocalStorage
3545
3546 Node* no_ctrl = NULL;
3547 Node* no_base = __ top();
3548 Node* zero = __ ConI(0);
3549
3550 float likely = PROB_LIKELY(0.999);
3551 float unlikely = PROB_UNLIKELY(0.999);
3552
3553 BasicType active_type = in_bytes(PtrQueue::byte_width_of_active()) == 4 ? T_INT : T_BYTE;
3554 assert(in_bytes(PtrQueue::byte_width_of_active()) == 4 || in_bytes(PtrQueue::byte_width_of_active()) == 1, "flag width");
3555
3556 // Offsets into the thread
3557 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 648
3558 PtrQueue::byte_offset_of_active());
3559 const int index_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 656
3560 PtrQueue::byte_offset_of_index());
3561 const int buffer_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 652
3562 PtrQueue::byte_offset_of_buf());
3563
3564 // Now the actual pointers into the thread
3565 Node* marking_adr = __ AddP(no_base, tls, __ ConX(marking_offset));
3566 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
3567 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
3568
3569 // Now some of the values
3570 Node* marking = __ load(__ ctrl(), marking_adr, TypeInt::INT, active_type, Compile::AliasIdxRaw);
3571
3572 // if (!marking)
3573 __ if_then(marking, BoolTest::ne, zero); {
3574 Node* index = __ load(__ ctrl(), index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw);
3575
3576 if (do_load) {
3577 // load original value
3578 // alias_idx correct??
3579 pre_val = __ load(no_ctrl, adr, val_type, bt, alias_idx);
3580 }
3581
3582 // if (pre_val != NULL)
3583 __ if_then(pre_val, BoolTest::ne, null()); {
3584 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
3585
3586 // is the queue for this thread full?
3587 __ if_then(index, BoolTest::ne, zero, likely); {
3588
3589 // decrement the index
3590 Node* next_index = __ SubI(index, __ ConI(sizeof(intptr_t)));
3591 Node* next_indexX = next_index;
3592 #ifdef _LP64
3593 // We could refine the type for what it's worth
3594 // const TypeLong* lidxtype = TypeLong::make(CONST64(0), get_size_from_queue);
3595 next_indexX = _gvn.transform( new (C) ConvI2LNode(next_index, TypeLong::make(0, max_jlong, Type::WidenMax)) );
3596 #endif
3597
3598 // Now get the buffer location we will log the previous value into and store it
3599 Node *log_addr = __ AddP(no_base, buffer, next_indexX);
3600 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw);
3601 // update the index
3602 __ store(__ ctrl(), index_adr, next_index, T_INT, Compile::AliasIdxRaw);
3603
3604 } __ else_(); {
3605
3606 // logging buffer is full, call the runtime
3607 const TypeFunc *tf = OptoRuntime::g1_wb_pre_Type();
3608 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), "g1_wb_pre", pre_val, tls);
3609 } __ end_if(); // (!index)
3610 } __ end_if(); // (pre_val != NULL)
3611 } __ end_if(); // (!marking)
3612
3613 // Final sync IdealKit and GraphKit.
3614 final_sync(ideal);
3615 }
3616
3617 //
3618 // Update the card table and add card address to the queue
3619 //
3620 void GraphKit::g1_mark_card(IdealKit& ideal,
3621 Node* card_adr,
3622 Node* oop_store,
3623 uint oop_alias_idx,
3624 Node* index,
3625 Node* index_adr,
3626 Node* buffer,
3627 const TypeFunc* tf) {
3628
3629 Node* zero = __ ConI(0);
3630 Node* no_base = __ top();
3631 BasicType card_bt = T_BYTE;
3632 // Smash zero into card. MUST BE ORDERED WRT TO STORE
3633 __ storeCM(__ ctrl(), card_adr, zero, oop_store, oop_alias_idx, card_bt, Compile::AliasIdxRaw);
3634
3635 // Now do the queue work
3636 __ if_then(index, BoolTest::ne, zero); {
3637
3638 Node* next_index = __ SubI(index, __ ConI(sizeof(intptr_t)));
3639 Node* next_indexX = next_index;
3640 #ifdef _LP64
3641 // We could refine the type for what it's worth
3642 // const TypeLong* lidxtype = TypeLong::make(CONST64(0), get_size_from_queue);
3643 next_indexX = _gvn.transform( new (C) ConvI2LNode(next_index, TypeLong::make(0, max_jlong, Type::WidenMax)) );
3644 #endif // _LP64
3645 Node* log_addr = __ AddP(no_base, buffer, next_indexX);
3646
3647 __ store(__ ctrl(), log_addr, card_adr, T_ADDRESS, Compile::AliasIdxRaw);
3648 __ store(__ ctrl(), index_adr, next_index, T_INT, Compile::AliasIdxRaw);
3649
3650 } __ else_(); {
3651 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), "g1_wb_post", card_adr, __ thread());
3652 } __ end_if();
3653
3654 }
3655
3656 void GraphKit::g1_write_barrier_post(Node* oop_store,
3657 Node* obj,
3658 Node* adr,
3659 uint alias_idx,
3660 Node* val,
3661 BasicType bt,
3662 bool use_precise) {
3663 // If we are writing a NULL then we need no post barrier
3664
3665 if (val != NULL && val->is_Con() && val->bottom_type() == TypePtr::NULL_PTR) {
3666 // Must be NULL
3667 const Type* t = val->bottom_type();
3668 assert(t == Type::TOP || t == TypePtr::NULL_PTR, "must be NULL");
3669 // No post barrier if writing NULLx
3670 return;
3671 }
3672
3673 if (!use_precise) {
3674 // All card marks for a (non-array) instance are in one place:
3675 adr = obj;
3676 }
3677 // (Else it's an array (or unknown), and we want more precise card marks.)
3678 assert(adr != NULL, "");
3679
3680 IdealKit ideal(this, true);
3681
3682 Node* tls = __ thread(); // ThreadLocalStorage
3683
3684 Node* no_base = __ top();
3685 float likely = PROB_LIKELY(0.999);
3686 float unlikely = PROB_UNLIKELY(0.999);
3687 Node* zero = __ ConI(0);
3688 Node* zeroX = __ ConX(0);
3689
3690 // Get the alias_index for raw card-mark memory
3691 const TypePtr* card_type = TypeRawPtr::BOTTOM;
3692
3693 const TypeFunc *tf = OptoRuntime::g1_wb_post_Type();
3694
3695 // Offsets into the thread
3696 const int index_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
3697 PtrQueue::byte_offset_of_index());
3698 const int buffer_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
3699 PtrQueue::byte_offset_of_buf());
3700
3701 // Pointers into the thread
3702
3703 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
3704 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
3705
3706 // Now some values
3707 // Use ctrl to avoid hoisting these values past a safepoint, which could
3708 // potentially reset these fields in the JavaThread.
3709 Node* index = __ load(__ ctrl(), index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw);
3710 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
3711
3712 // Convert the store obj pointer to an int prior to doing math on it
3713 // Must use ctrl to prevent "integerized oop" existing across safepoint
3714 Node* cast = __ CastPX(__ ctrl(), adr);
3715
3716 // Divide pointer by card size
3717 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
3718
3719 // Combine card table base and card offset
3720 Node* card_adr = __ AddP(no_base, byte_map_base_node(), card_offset );
3721
3722 // If we know the value being stored does it cross regions?
3723
3724 if (val != NULL) {
3725 // Does the store cause us to cross regions?
3726
3727 // Should be able to do an unsigned compare of region_size instead of
3728 // and extra shift. Do we have an unsigned compare??
3729 // Node* region_size = __ ConI(1 << HeapRegion::LogOfHRGrainBytes);
3730 Node* xor_res = __ URShiftX ( __ XorX( cast, __ CastPX(__ ctrl(), val)), __ ConI(HeapRegion::LogOfHRGrainBytes));
3731
3732 // if (xor_res == 0) same region so skip
3733 __ if_then(xor_res, BoolTest::ne, zeroX); {
3734
3735 // No barrier if we are storing a NULL
3736 __ if_then(val, BoolTest::ne, null(), unlikely); {
3737
3738 // Ok must mark the card if not already dirty
3739
3740 // load the original value of the card
3741 Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
3742
3743 __ if_then(card_val, BoolTest::ne, zero); {
3744 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
3745 } __ end_if();
3746 } __ end_if();
3747 } __ end_if();
3748 } else {
3749 // Object.clone() instrinsic uses this path.
3750 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
3751 }
3752
3753 // Final sync IdealKit and GraphKit.
3754 final_sync(ideal);
3755 }
3756 #undef __
3757
3758
3759
3760 Node* GraphKit::load_String_offset(Node* ctrl, Node* str) {
3761 if (java_lang_String::has_offset_field()) {
3762 int offset_offset = java_lang_String::offset_offset_in_bytes();
3763 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
3764 false, NULL, 0);
3765 const TypePtr* offset_field_type = string_type->add_offset(offset_offset);
3766 int offset_field_idx = C->get_alias_index(offset_field_type);
3767 return make_load(ctrl,
3768 basic_plus_adr(str, str, offset_offset),
3769 TypeInt::INT, T_INT, offset_field_idx);
3770 } else {
3771 return intcon(0);
3772 }
3773 }
3774
3775 Node* GraphKit::load_String_length(Node* ctrl, Node* str) {
3776 if (java_lang_String::has_count_field()) {
3777 int count_offset = java_lang_String::count_offset_in_bytes();
3778 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
3779 false, NULL, 0);
3780 const TypePtr* count_field_type = string_type->add_offset(count_offset);
3781 int count_field_idx = C->get_alias_index(count_field_type);
3782 return make_load(ctrl,
3783 basic_plus_adr(str, str, count_offset),
3784 TypeInt::INT, T_INT, count_field_idx);
3785 } else {
3786 return load_array_length(load_String_value(ctrl, str));
3787 }
3788 }
3789
3790 Node* GraphKit::load_String_value(Node* ctrl, Node* str) {
3791 int value_offset = java_lang_String::value_offset_in_bytes();
3792 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
3793 false, NULL, 0);
3794 const TypePtr* value_field_type = string_type->add_offset(value_offset);
3795 const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull,
3796 TypeAry::make(TypeInt::CHAR,TypeInt::POS),
3797 ciTypeArrayKlass::make(T_CHAR), true, 0);
3798 int value_field_idx = C->get_alias_index(value_field_type);
3799 return make_load(ctrl, basic_plus_adr(str, str, value_offset),
3800 value_type, T_OBJECT, value_field_idx);
3801 }
3802
3803 void GraphKit::store_String_offset(Node* ctrl, Node* str, Node* value) {
3804 int offset_offset = java_lang_String::offset_offset_in_bytes();
3805 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
3806 false, NULL, 0);
3807 const TypePtr* offset_field_type = string_type->add_offset(offset_offset);
3808 int offset_field_idx = C->get_alias_index(offset_field_type);
3809 store_to_memory(ctrl, basic_plus_adr(str, offset_offset),
3810 value, T_INT, offset_field_idx);
3811 }
3812
3813 void GraphKit::store_String_value(Node* ctrl, Node* str, Node* value) {
3814 int value_offset = java_lang_String::value_offset_in_bytes();
3815 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
3816 false, NULL, 0);
3817 const TypePtr* value_field_type = string_type->add_offset(value_offset);
3818 const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull,
3819 TypeAry::make(TypeInt::CHAR,TypeInt::POS),
3820 ciTypeArrayKlass::make(T_CHAR), true, 0);
3821 int value_field_idx = C->get_alias_index(value_field_type);
3822 store_to_memory(ctrl, basic_plus_adr(str, value_offset),
3823 value, T_OBJECT, value_field_idx);
3824 }
3825
3826 void GraphKit::store_String_length(Node* ctrl, Node* str, Node* value) {
3827 int count_offset = java_lang_String::count_offset_in_bytes();
3828 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
3829 false, NULL, 0);
3830 const TypePtr* count_field_type = string_type->add_offset(count_offset);
3831 int count_field_idx = C->get_alias_index(count_field_type);
3832 store_to_memory(ctrl, basic_plus_adr(str, count_offset),
3833 value, T_INT, count_field_idx);
3834 }