1 /*
2 * Copyright (c) 2001, 2015, 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/g1/g1SATBCardTableModRefBS.hpp"
28 #include "gc/g1/heapRegion.hpp"
29 #include "gc/shared/barrierSet.hpp"
30 #include "gc/shared/cardTableModRefBS.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "gc/shenandoah/brooksPointer.hpp"
33 #include "opto/addnode.hpp"
34 #include "opto/castnode.hpp"
35 #include "opto/convertnode.hpp"
36 #include "opto/graphKit.hpp"
37 #include "opto/idealKit.hpp"
38 #include "opto/intrinsicnode.hpp"
39 #include "opto/locknode.hpp"
40 #include "opto/machnode.hpp"
41 #include "opto/opaquenode.hpp"
42 #include "opto/parse.hpp"
43 #include "opto/rootnode.hpp"
44 #include "opto/runtime.hpp"
45 #include "opto/shenandoahSupport.hpp"
46 #include "runtime/deoptimization.hpp"
47 #include "runtime/sharedRuntime.hpp"
48
49 //----------------------------GraphKit-----------------------------------------
50 // Main utility constructor.
51 GraphKit::GraphKit(JVMState* jvms)
52 : Phase(Phase::Parser),
53 _env(C->env()),
54 _gvn(*C->initial_gvn())
55 {
56 _exceptions = jvms->map()->next_exception();
57 if (_exceptions != NULL) jvms->map()->set_next_exception(NULL);
58 set_jvms(jvms);
59 }
60
61 // Private constructor for parser.
62 GraphKit::GraphKit()
63 : Phase(Phase::Parser),
64 _env(C->env()),
65 _gvn(*C->initial_gvn())
66 {
67 _exceptions = NULL;
68 set_map(NULL);
69 debug_only(_sp = -99);
70 debug_only(set_bci(-99));
71 }
72
73
74
75 //---------------------------clean_stack---------------------------------------
76 // Clear away rubbish from the stack area of the JVM state.
77 // This destroys any arguments that may be waiting on the stack.
78 void GraphKit::clean_stack(int from_sp) {
79 SafePointNode* map = this->map();
80 JVMState* jvms = this->jvms();
81 int stk_size = jvms->stk_size();
82 int stkoff = jvms->stkoff();
83 Node* top = this->top();
84 for (int i = from_sp; i < stk_size; i++) {
85 if (map->in(stkoff + i) != top) {
86 map->set_req(stkoff + i, top);
87 }
88 }
89 }
90
91
92 //--------------------------------sync_jvms-----------------------------------
93 // Make sure our current jvms agrees with our parse state.
94 JVMState* GraphKit::sync_jvms() const {
95 JVMState* jvms = this->jvms();
96 jvms->set_bci(bci()); // Record the new bci in the JVMState
97 jvms->set_sp(sp()); // Record the new sp in the JVMState
98 assert(jvms_in_sync(), "jvms is now in sync");
99 return jvms;
100 }
101
102 //--------------------------------sync_jvms_for_reexecute---------------------
103 // Make sure our current jvms agrees with our parse state. This version
104 // uses the reexecute_sp for reexecuting bytecodes.
105 JVMState* GraphKit::sync_jvms_for_reexecute() {
106 JVMState* jvms = this->jvms();
107 jvms->set_bci(bci()); // Record the new bci in the JVMState
108 jvms->set_sp(reexecute_sp()); // Record the new sp in the JVMState
109 return jvms;
110 }
111
112 #ifdef ASSERT
113 bool GraphKit::jvms_in_sync() const {
114 Parse* parse = is_Parse();
115 if (parse == NULL) {
116 if (bci() != jvms()->bci()) return false;
117 if (sp() != (int)jvms()->sp()) return false;
118 return true;
119 }
120 if (jvms()->method() != parse->method()) return false;
121 if (jvms()->bci() != parse->bci()) return false;
122 int jvms_sp = jvms()->sp();
123 if (jvms_sp != parse->sp()) return false;
124 int jvms_depth = jvms()->depth();
125 if (jvms_depth != parse->depth()) return false;
126 return true;
127 }
128
129 // Local helper checks for special internal merge points
130 // used to accumulate and merge exception states.
131 // They are marked by the region's in(0) edge being the map itself.
132 // Such merge points must never "escape" into the parser at large,
133 // until they have been handed to gvn.transform.
134 static bool is_hidden_merge(Node* reg) {
135 if (reg == NULL) return false;
136 if (reg->is_Phi()) {
137 reg = reg->in(0);
138 if (reg == NULL) return false;
139 }
140 return reg->is_Region() && reg->in(0) != NULL && reg->in(0)->is_Root();
141 }
142
143 void GraphKit::verify_map() const {
144 if (map() == NULL) return; // null map is OK
145 assert(map()->req() <= jvms()->endoff(), "no extra garbage on map");
146 assert(!map()->has_exceptions(), "call add_exception_states_from 1st");
147 assert(!is_hidden_merge(control()), "call use_exception_state, not set_map");
148 }
149
150 void GraphKit::verify_exception_state(SafePointNode* ex_map) {
151 assert(ex_map->next_exception() == NULL, "not already part of a chain");
152 assert(has_saved_ex_oop(ex_map), "every exception state has an ex_oop");
153 }
154 #endif
155
156 //---------------------------stop_and_kill_map---------------------------------
157 // Set _map to NULL, signalling a stop to further bytecode execution.
158 // First smash the current map's control to a constant, to mark it dead.
159 void GraphKit::stop_and_kill_map() {
160 SafePointNode* dead_map = stop();
161 if (dead_map != NULL) {
162 dead_map->disconnect_inputs(NULL, C); // Mark the map as killed.
163 assert(dead_map->is_killed(), "must be so marked");
164 }
165 }
166
167
168 //--------------------------------stopped--------------------------------------
169 // Tell if _map is NULL, or control is top.
170 bool GraphKit::stopped() {
171 if (map() == NULL) return true;
172 else if (control() == top()) return true;
173 else return false;
174 }
175
176
177 //-----------------------------has_ex_handler----------------------------------
178 // Tell if this method or any caller method has exception handlers.
179 bool GraphKit::has_ex_handler() {
180 for (JVMState* jvmsp = jvms(); jvmsp != NULL; jvmsp = jvmsp->caller()) {
181 if (jvmsp->has_method() && jvmsp->method()->has_exception_handlers()) {
182 return true;
183 }
184 }
185 return false;
186 }
187
188 //------------------------------save_ex_oop------------------------------------
189 // Save an exception without blowing stack contents or other JVM state.
190 void GraphKit::set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop) {
191 assert(!has_saved_ex_oop(ex_map), "clear ex-oop before setting again");
192 ex_map->add_req(ex_oop);
193 debug_only(verify_exception_state(ex_map));
194 }
195
196 inline static Node* common_saved_ex_oop(SafePointNode* ex_map, bool clear_it) {
197 assert(GraphKit::has_saved_ex_oop(ex_map), "ex_oop must be there");
198 Node* ex_oop = ex_map->in(ex_map->req()-1);
199 if (clear_it) ex_map->del_req(ex_map->req()-1);
200 return ex_oop;
201 }
202
203 //-----------------------------saved_ex_oop------------------------------------
204 // Recover a saved exception from its map.
205 Node* GraphKit::saved_ex_oop(SafePointNode* ex_map) {
206 return common_saved_ex_oop(ex_map, false);
207 }
208
209 //--------------------------clear_saved_ex_oop---------------------------------
210 // Erase a previously saved exception from its map.
211 Node* GraphKit::clear_saved_ex_oop(SafePointNode* ex_map) {
212 return common_saved_ex_oop(ex_map, true);
213 }
214
215 #ifdef ASSERT
216 //---------------------------has_saved_ex_oop----------------------------------
217 // Erase a previously saved exception from its map.
218 bool GraphKit::has_saved_ex_oop(SafePointNode* ex_map) {
219 return ex_map->req() == ex_map->jvms()->endoff()+1;
220 }
221 #endif
222
223 //-------------------------make_exception_state--------------------------------
224 // Turn the current JVM state into an exception state, appending the ex_oop.
225 SafePointNode* GraphKit::make_exception_state(Node* ex_oop) {
226 sync_jvms();
227 SafePointNode* ex_map = stop(); // do not manipulate this map any more
228 set_saved_ex_oop(ex_map, ex_oop);
229 return ex_map;
230 }
231
232
233 //--------------------------add_exception_state--------------------------------
234 // Add an exception to my list of exceptions.
235 void GraphKit::add_exception_state(SafePointNode* ex_map) {
236 if (ex_map == NULL || ex_map->control() == top()) {
237 return;
238 }
239 #ifdef ASSERT
240 verify_exception_state(ex_map);
241 if (has_exceptions()) {
242 assert(ex_map->jvms()->same_calls_as(_exceptions->jvms()), "all collected exceptions must come from the same place");
243 }
244 #endif
245
246 // If there is already an exception of exactly this type, merge with it.
247 // In particular, null-checks and other low-level exceptions common up here.
248 Node* ex_oop = saved_ex_oop(ex_map);
249 const Type* ex_type = _gvn.type(ex_oop);
250 if (ex_oop == top()) {
251 // No action needed.
252 return;
253 }
254 assert(ex_type->isa_instptr(), "exception must be an instance");
255 for (SafePointNode* e2 = _exceptions; e2 != NULL; e2 = e2->next_exception()) {
256 const Type* ex_type2 = _gvn.type(saved_ex_oop(e2));
257 // We check sp also because call bytecodes can generate exceptions
258 // both before and after arguments are popped!
259 if (ex_type2 == ex_type
260 && e2->_jvms->sp() == ex_map->_jvms->sp()) {
261 combine_exception_states(ex_map, e2);
262 return;
263 }
264 }
265
266 // No pre-existing exception of the same type. Chain it on the list.
267 push_exception_state(ex_map);
268 }
269
270 //-----------------------add_exception_states_from-----------------------------
271 void GraphKit::add_exception_states_from(JVMState* jvms) {
272 SafePointNode* ex_map = jvms->map()->next_exception();
273 if (ex_map != NULL) {
274 jvms->map()->set_next_exception(NULL);
275 for (SafePointNode* next_map; ex_map != NULL; ex_map = next_map) {
276 next_map = ex_map->next_exception();
277 ex_map->set_next_exception(NULL);
278 add_exception_state(ex_map);
279 }
280 }
281 }
282
283 //-----------------------transfer_exceptions_into_jvms-------------------------
284 JVMState* GraphKit::transfer_exceptions_into_jvms() {
285 if (map() == NULL) {
286 // We need a JVMS to carry the exceptions, but the map has gone away.
287 // Create a scratch JVMS, cloned from any of the exception states...
288 if (has_exceptions()) {
289 _map = _exceptions;
290 _map = clone_map();
291 _map->set_next_exception(NULL);
292 clear_saved_ex_oop(_map);
293 debug_only(verify_map());
294 } else {
295 // ...or created from scratch
296 JVMState* jvms = new (C) JVMState(_method, NULL);
297 jvms->set_bci(_bci);
298 jvms->set_sp(_sp);
299 jvms->set_map(new SafePointNode(TypeFunc::Parms, jvms));
300 set_jvms(jvms);
301 for (uint i = 0; i < map()->req(); i++) map()->init_req(i, top());
302 set_all_memory(top());
303 while (map()->req() < jvms->endoff()) map()->add_req(top());
304 }
305 // (This is a kludge, in case you didn't notice.)
306 set_control(top());
307 }
308 JVMState* jvms = sync_jvms();
309 assert(!jvms->map()->has_exceptions(), "no exceptions on this map yet");
310 jvms->map()->set_next_exception(_exceptions);
311 _exceptions = NULL; // done with this set of exceptions
312 return jvms;
313 }
314
315 static inline void add_n_reqs(Node* dstphi, Node* srcphi) {
316 assert(is_hidden_merge(dstphi), "must be a special merge node");
317 assert(is_hidden_merge(srcphi), "must be a special merge node");
318 uint limit = srcphi->req();
319 for (uint i = PhiNode::Input; i < limit; i++) {
320 dstphi->add_req(srcphi->in(i));
321 }
322 }
323 static inline void add_one_req(Node* dstphi, Node* src) {
324 assert(is_hidden_merge(dstphi), "must be a special merge node");
325 assert(!is_hidden_merge(src), "must not be a special merge node");
326 dstphi->add_req(src);
327 }
328
329 //-----------------------combine_exception_states------------------------------
330 // This helper function combines exception states by building phis on a
331 // specially marked state-merging region. These regions and phis are
332 // untransformed, and can build up gradually. The region is marked by
333 // having a control input of its exception map, rather than NULL. Such
334 // regions do not appear except in this function, and in use_exception_state.
335 void GraphKit::combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map) {
336 if (failing()) return; // dying anyway...
337 JVMState* ex_jvms = ex_map->_jvms;
338 assert(ex_jvms->same_calls_as(phi_map->_jvms), "consistent call chains");
339 assert(ex_jvms->stkoff() == phi_map->_jvms->stkoff(), "matching locals");
340 assert(ex_jvms->sp() == phi_map->_jvms->sp(), "matching stack sizes");
341 assert(ex_jvms->monoff() == phi_map->_jvms->monoff(), "matching JVMS");
342 assert(ex_jvms->scloff() == phi_map->_jvms->scloff(), "matching scalar replaced objects");
343 assert(ex_map->req() == phi_map->req(), "matching maps");
344 uint tos = ex_jvms->stkoff() + ex_jvms->sp();
345 Node* hidden_merge_mark = root();
346 Node* region = phi_map->control();
347 MergeMemNode* phi_mem = phi_map->merged_memory();
348 MergeMemNode* ex_mem = ex_map->merged_memory();
349 if (region->in(0) != hidden_merge_mark) {
350 // The control input is not (yet) a specially-marked region in phi_map.
351 // Make it so, and build some phis.
352 region = new RegionNode(2);
353 _gvn.set_type(region, Type::CONTROL);
354 region->set_req(0, hidden_merge_mark); // marks an internal ex-state
355 region->init_req(1, phi_map->control());
356 phi_map->set_control(region);
357 Node* io_phi = PhiNode::make(region, phi_map->i_o(), Type::ABIO);
358 record_for_igvn(io_phi);
359 _gvn.set_type(io_phi, Type::ABIO);
360 phi_map->set_i_o(io_phi);
361 for (MergeMemStream mms(phi_mem); mms.next_non_empty(); ) {
362 Node* m = mms.memory();
363 Node* m_phi = PhiNode::make(region, m, Type::MEMORY, mms.adr_type(C));
364 record_for_igvn(m_phi);
365 _gvn.set_type(m_phi, Type::MEMORY);
366 mms.set_memory(m_phi);
367 }
368 }
369
370 // Either or both of phi_map and ex_map might already be converted into phis.
371 Node* ex_control = ex_map->control();
372 // if there is special marking on ex_map also, we add multiple edges from src
373 bool add_multiple = (ex_control->in(0) == hidden_merge_mark);
374 // how wide was the destination phi_map, originally?
375 uint orig_width = region->req();
376
377 if (add_multiple) {
378 add_n_reqs(region, ex_control);
379 add_n_reqs(phi_map->i_o(), ex_map->i_o());
380 } else {
381 // ex_map has no merges, so we just add single edges everywhere
382 add_one_req(region, ex_control);
383 add_one_req(phi_map->i_o(), ex_map->i_o());
384 }
385 for (MergeMemStream mms(phi_mem, ex_mem); mms.next_non_empty2(); ) {
386 if (mms.is_empty()) {
387 // get a copy of the base memory, and patch some inputs into it
388 const TypePtr* adr_type = mms.adr_type(C);
389 Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
390 assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
391 mms.set_memory(phi);
392 // Prepare to append interesting stuff onto the newly sliced phi:
393 while (phi->req() > orig_width) phi->del_req(phi->req()-1);
394 }
395 // Append stuff from ex_map:
396 if (add_multiple) {
397 add_n_reqs(mms.memory(), mms.memory2());
398 } else {
399 add_one_req(mms.memory(), mms.memory2());
400 }
401 }
402 uint limit = ex_map->req();
403 for (uint i = TypeFunc::Parms; i < limit; i++) {
404 // Skip everything in the JVMS after tos. (The ex_oop follows.)
405 if (i == tos) i = ex_jvms->monoff();
406 Node* src = ex_map->in(i);
407 Node* dst = phi_map->in(i);
408 if (src != dst) {
409 PhiNode* phi;
410 if (dst->in(0) != region) {
411 dst = phi = PhiNode::make(region, dst, _gvn.type(dst));
412 record_for_igvn(phi);
413 _gvn.set_type(phi, phi->type());
414 phi_map->set_req(i, dst);
415 // Prepare to append interesting stuff onto the new phi:
416 while (dst->req() > orig_width) dst->del_req(dst->req()-1);
417 } else {
418 assert(dst->is_Phi(), "nobody else uses a hidden region");
419 phi = dst->as_Phi();
420 }
421 if (add_multiple && src->in(0) == ex_control) {
422 // Both are phis.
423 add_n_reqs(dst, src);
424 } else {
425 while (dst->req() < region->req()) add_one_req(dst, src);
426 }
427 const Type* srctype = _gvn.type(src);
428 if (phi->type() != srctype) {
429 const Type* dsttype = phi->type()->meet_speculative(srctype);
430 if (phi->type() != dsttype) {
431 phi->set_type(dsttype);
432 _gvn.set_type(phi, dsttype);
433 }
434 }
435 }
436 }
437 phi_map->merge_replaced_nodes_with(ex_map);
438 }
439
440 //--------------------------use_exception_state--------------------------------
441 Node* GraphKit::use_exception_state(SafePointNode* phi_map) {
442 if (failing()) { stop(); return top(); }
443 Node* region = phi_map->control();
444 Node* hidden_merge_mark = root();
445 assert(phi_map->jvms()->map() == phi_map, "sanity: 1-1 relation");
446 Node* ex_oop = clear_saved_ex_oop(phi_map);
447 if (region->in(0) == hidden_merge_mark) {
448 // Special marking for internal ex-states. Process the phis now.
449 region->set_req(0, region); // now it's an ordinary region
450 set_jvms(phi_map->jvms()); // ...so now we can use it as a map
451 // Note: Setting the jvms also sets the bci and sp.
452 set_control(_gvn.transform(region));
453 uint tos = jvms()->stkoff() + sp();
454 for (uint i = 1; i < tos; i++) {
455 Node* x = phi_map->in(i);
456 if (x->in(0) == region) {
457 assert(x->is_Phi(), "expected a special phi");
458 phi_map->set_req(i, _gvn.transform(x));
459 }
460 }
461 for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
462 Node* x = mms.memory();
463 if (x->in(0) == region) {
464 assert(x->is_Phi(), "nobody else uses a hidden region");
465 mms.set_memory(_gvn.transform(x));
466 }
467 }
468 if (ex_oop->in(0) == region) {
469 assert(ex_oop->is_Phi(), "expected a special phi");
470 ex_oop = _gvn.transform(ex_oop);
471 }
472 } else {
473 set_jvms(phi_map->jvms());
474 }
475
476 assert(!is_hidden_merge(phi_map->control()), "hidden ex. states cleared");
477 assert(!is_hidden_merge(phi_map->i_o()), "hidden ex. states cleared");
478 return ex_oop;
479 }
480
481 //---------------------------------java_bc-------------------------------------
482 Bytecodes::Code GraphKit::java_bc() const {
483 ciMethod* method = this->method();
484 int bci = this->bci();
485 if (method != NULL && bci != InvocationEntryBci)
486 return method->java_code_at_bci(bci);
487 else
488 return Bytecodes::_illegal;
489 }
490
491 void GraphKit::uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
492 bool must_throw) {
493 // if the exception capability is set, then we will generate code
494 // to check the JavaThread.should_post_on_exceptions flag to see
495 // if we actually need to report exception events (for this
496 // thread). If we don't need to report exception events, we will
497 // take the normal fast path provided by add_exception_events. If
498 // exception event reporting is enabled for this thread, we will
499 // take the uncommon_trap in the BuildCutout below.
500
501 // first must access the should_post_on_exceptions_flag in this thread's JavaThread
502 Node* jthread = _gvn.transform(new ThreadLocalNode());
503 Node* adr = basic_plus_adr(top(), jthread, in_bytes(JavaThread::should_post_on_exceptions_flag_offset()));
504 Node* should_post_flag = make_load(control(), adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw, MemNode::unordered);
505
506 // Test the should_post_on_exceptions_flag vs. 0
507 Node* chk = _gvn.transform( new CmpINode(should_post_flag, intcon(0)) );
508 Node* tst = _gvn.transform( new BoolNode(chk, BoolTest::eq) );
509
510 // Branch to slow_path if should_post_on_exceptions_flag was true
511 { BuildCutout unless(this, tst, PROB_MAX);
512 // Do not try anything fancy if we're notifying the VM on every throw.
513 // Cf. case Bytecodes::_athrow in parse2.cpp.
514 uncommon_trap(reason, Deoptimization::Action_none,
515 (ciKlass*)NULL, (char*)NULL, must_throw);
516 }
517
518 }
519
520 //------------------------------builtin_throw----------------------------------
521 void GraphKit::builtin_throw(Deoptimization::DeoptReason reason, Node* arg) {
522 bool must_throw = true;
523
524 if (env()->jvmti_can_post_on_exceptions()) {
525 // check if we must post exception events, take uncommon trap if so
526 uncommon_trap_if_should_post_on_exceptions(reason, must_throw);
527 // here if should_post_on_exceptions is false
528 // continue on with the normal codegen
529 }
530
531 // If this particular condition has not yet happened at this
532 // bytecode, then use the uncommon trap mechanism, and allow for
533 // a future recompilation if several traps occur here.
534 // If the throw is hot, try to use a more complicated inline mechanism
535 // which keeps execution inside the compiled code.
536 bool treat_throw_as_hot = false;
537 ciMethodData* md = method()->method_data();
538
539 if (ProfileTraps) {
540 if (too_many_traps(reason)) {
541 treat_throw_as_hot = true;
542 }
543 // (If there is no MDO at all, assume it is early in
544 // execution, and that any deopts are part of the
545 // startup transient, and don't need to be remembered.)
546
547 // Also, if there is a local exception handler, treat all throws
548 // as hot if there has been at least one in this method.
549 if (C->trap_count(reason) != 0
550 && method()->method_data()->trap_count(reason) != 0
551 && has_ex_handler()) {
552 treat_throw_as_hot = true;
553 }
554 }
555
556 // If this throw happens frequently, an uncommon trap might cause
557 // a performance pothole. If there is a local exception handler,
558 // and if this particular bytecode appears to be deoptimizing often,
559 // let us handle the throw inline, with a preconstructed instance.
560 // Note: If the deopt count has blown up, the uncommon trap
561 // runtime is going to flush this nmethod, not matter what.
562 if (treat_throw_as_hot
563 && (!StackTraceInThrowable || OmitStackTraceInFastThrow)) {
564 // If the throw is local, we use a pre-existing instance and
565 // punt on the backtrace. This would lead to a missing backtrace
566 // (a repeat of 4292742) if the backtrace object is ever asked
567 // for its backtrace.
568 // Fixing this remaining case of 4292742 requires some flavor of
569 // escape analysis. Leave that for the future.
570 ciInstance* ex_obj = NULL;
571 switch (reason) {
572 case Deoptimization::Reason_null_check:
573 ex_obj = env()->NullPointerException_instance();
574 break;
575 case Deoptimization::Reason_div0_check:
576 ex_obj = env()->ArithmeticException_instance();
577 break;
578 case Deoptimization::Reason_range_check:
579 ex_obj = env()->ArrayIndexOutOfBoundsException_instance();
580 break;
581 case Deoptimization::Reason_class_check:
582 if (java_bc() == Bytecodes::_aastore) {
583 ex_obj = env()->ArrayStoreException_instance();
584 } else {
585 ex_obj = env()->ClassCastException_instance();
586 }
587 break;
588 }
589 if (failing()) { stop(); return; } // exception allocation might fail
590 if (ex_obj != NULL) {
591 // Cheat with a preallocated exception object.
592 if (C->log() != NULL)
593 C->log()->elem("hot_throw preallocated='1' reason='%s'",
594 Deoptimization::trap_reason_name(reason));
595 const TypeInstPtr* ex_con = TypeInstPtr::make(ex_obj);
596 Node* ex_node = _gvn.transform(ConNode::make(ex_con));
597
598 // Clear the detail message of the preallocated exception object.
599 // Weblogic sometimes mutates the detail message of exceptions
600 // using reflection.
601 int offset = java_lang_Throwable::get_detailMessage_offset();
602 const TypePtr* adr_typ = ex_con->add_offset(offset);
603
604 Node *adr = basic_plus_adr(ex_node, ex_node, offset);
605 const TypeOopPtr* val_type = TypeOopPtr::make_from_klass(env()->String_klass());
606 // Conservatively release stores of object references.
607 Node *store = store_oop_to_object(control(), ex_node, adr, adr_typ, null(), val_type, T_OBJECT, MemNode::release);
608
609 add_exception_state(make_exception_state(ex_node));
610 return;
611 }
612 }
613
614 // %%% Maybe add entry to OptoRuntime which directly throws the exc.?
615 // It won't be much cheaper than bailing to the interp., since we'll
616 // have to pass up all the debug-info, and the runtime will have to
617 // create the stack trace.
618
619 // Usual case: Bail to interpreter.
620 // Reserve the right to recompile if we haven't seen anything yet.
621
622 ciMethod* m = Deoptimization::reason_is_speculate(reason) ? C->method() : NULL;
623 Deoptimization::DeoptAction action = Deoptimization::Action_maybe_recompile;
624 if (treat_throw_as_hot
625 && (method()->method_data()->trap_recompiled_at(bci(), m)
626 || C->too_many_traps(reason))) {
627 // We cannot afford to take more traps here. Suffer in the interpreter.
628 if (C->log() != NULL)
629 C->log()->elem("hot_throw preallocated='0' reason='%s' mcount='%d'",
630 Deoptimization::trap_reason_name(reason),
631 C->trap_count(reason));
632 action = Deoptimization::Action_none;
633 }
634
635 // "must_throw" prunes the JVM state to include only the stack, if there
636 // are no local exception handlers. This should cut down on register
637 // allocation time and code size, by drastically reducing the number
638 // of in-edges on the call to the uncommon trap.
639
640 uncommon_trap(reason, action, (ciKlass*)NULL, (char*)NULL, must_throw);
641 }
642
643
644 //----------------------------PreserveJVMState---------------------------------
645 PreserveJVMState::PreserveJVMState(GraphKit* kit, bool clone_map) {
646 debug_only(kit->verify_map());
647 _kit = kit;
648 _map = kit->map(); // preserve the map
649 _sp = kit->sp();
650 kit->set_map(clone_map ? kit->clone_map() : NULL);
651 #ifdef ASSERT
652 _bci = kit->bci();
653 Parse* parser = kit->is_Parse();
654 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
655 _block = block;
656 #endif
657 }
658 PreserveJVMState::~PreserveJVMState() {
659 GraphKit* kit = _kit;
660 #ifdef ASSERT
661 assert(kit->bci() == _bci, "bci must not shift");
662 Parse* parser = kit->is_Parse();
663 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
664 assert(block == _block, "block must not shift");
665 #endif
666 kit->set_map(_map);
667 kit->set_sp(_sp);
668 }
669
670
671 //-----------------------------BuildCutout-------------------------------------
672 BuildCutout::BuildCutout(GraphKit* kit, Node* p, float prob, float cnt)
673 : PreserveJVMState(kit)
674 {
675 assert(p->is_Con() || p->is_Bool(), "test must be a bool");
676 SafePointNode* outer_map = _map; // preserved map is caller's
677 SafePointNode* inner_map = kit->map();
678 IfNode* iff = kit->create_and_map_if(outer_map->control(), p, prob, cnt);
679 outer_map->set_control(kit->gvn().transform( new IfTrueNode(iff) ));
680 inner_map->set_control(kit->gvn().transform( new IfFalseNode(iff) ));
681 }
682 BuildCutout::~BuildCutout() {
683 GraphKit* kit = _kit;
684 assert(kit->stopped(), "cutout code must stop, throw, return, etc.");
685 }
686
687 //---------------------------PreserveReexecuteState----------------------------
688 PreserveReexecuteState::PreserveReexecuteState(GraphKit* kit) {
689 assert(!kit->stopped(), "must call stopped() before");
690 _kit = kit;
691 _sp = kit->sp();
692 _reexecute = kit->jvms()->_reexecute;
693 }
694 PreserveReexecuteState::~PreserveReexecuteState() {
695 if (_kit->stopped()) return;
696 _kit->jvms()->_reexecute = _reexecute;
697 _kit->set_sp(_sp);
698 }
699
700 //------------------------------clone_map--------------------------------------
701 // Implementation of PreserveJVMState
702 //
703 // Only clone_map(...) here. If this function is only used in the
704 // PreserveJVMState class we may want to get rid of this extra
705 // function eventually and do it all there.
706
707 SafePointNode* GraphKit::clone_map() {
708 if (map() == NULL) return NULL;
709
710 // Clone the memory edge first
711 Node* mem = MergeMemNode::make(map()->memory());
712 gvn().set_type_bottom(mem);
713
714 SafePointNode *clonemap = (SafePointNode*)map()->clone();
715 JVMState* jvms = this->jvms();
716 JVMState* clonejvms = jvms->clone_shallow(C);
717 clonemap->set_memory(mem);
718 clonemap->set_jvms(clonejvms);
719 clonejvms->set_map(clonemap);
720 record_for_igvn(clonemap);
721 gvn().set_type_bottom(clonemap);
722 return clonemap;
723 }
724
725
726 //-----------------------------set_map_clone-----------------------------------
727 void GraphKit::set_map_clone(SafePointNode* m) {
728 _map = m;
729 _map = clone_map();
730 _map->set_next_exception(NULL);
731 debug_only(verify_map());
732 }
733
734
735 //----------------------------kill_dead_locals---------------------------------
736 // Detect any locals which are known to be dead, and force them to top.
737 void GraphKit::kill_dead_locals() {
738 // Consult the liveness information for the locals. If any
739 // of them are unused, then they can be replaced by top(). This
740 // should help register allocation time and cut down on the size
741 // of the deoptimization information.
742
743 // This call is made from many of the bytecode handling
744 // subroutines called from the Big Switch in do_one_bytecode.
745 // Every bytecode which might include a slow path is responsible
746 // for killing its dead locals. The more consistent we
747 // are about killing deads, the fewer useless phis will be
748 // constructed for them at various merge points.
749
750 // bci can be -1 (InvocationEntryBci). We return the entry
751 // liveness for the method.
752
753 if (method() == NULL || method()->code_size() == 0) {
754 // We are building a graph for a call to a native method.
755 // All locals are live.
756 return;
757 }
758
759 ResourceMark rm;
760
761 // Consult the liveness information for the locals. If any
762 // of them are unused, then they can be replaced by top(). This
763 // should help register allocation time and cut down on the size
764 // of the deoptimization information.
765 MethodLivenessResult live_locals = method()->liveness_at_bci(bci());
766
767 int len = (int)live_locals.size();
768 assert(len <= jvms()->loc_size(), "too many live locals");
769 for (int local = 0; local < len; local++) {
770 if (!live_locals.at(local)) {
771 set_local(local, top());
772 }
773 }
774 }
775
776 #ifdef ASSERT
777 //-------------------------dead_locals_are_killed------------------------------
778 // Return true if all dead locals are set to top in the map.
779 // Used to assert "clean" debug info at various points.
780 bool GraphKit::dead_locals_are_killed() {
781 if (method() == NULL || method()->code_size() == 0) {
782 // No locals need to be dead, so all is as it should be.
783 return true;
784 }
785
786 // Make sure somebody called kill_dead_locals upstream.
787 ResourceMark rm;
788 for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
789 if (jvms->loc_size() == 0) continue; // no locals to consult
790 SafePointNode* map = jvms->map();
791 ciMethod* method = jvms->method();
792 int bci = jvms->bci();
793 if (jvms == this->jvms()) {
794 bci = this->bci(); // it might not yet be synched
795 }
796 MethodLivenessResult live_locals = method->liveness_at_bci(bci);
797 int len = (int)live_locals.size();
798 if (!live_locals.is_valid() || len == 0)
799 // This method is trivial, or is poisoned by a breakpoint.
800 return true;
801 assert(len == jvms->loc_size(), "live map consistent with locals map");
802 for (int local = 0; local < len; local++) {
803 if (!live_locals.at(local) && map->local(jvms, local) != top()) {
804 if (PrintMiscellaneous && (Verbose || WizardMode)) {
805 tty->print_cr("Zombie local %d: ", local);
806 jvms->dump();
807 }
808 return false;
809 }
810 }
811 }
812 return true;
813 }
814
815 #endif //ASSERT
816
817 // Helper function for enforcing certain bytecodes to reexecute if
818 // deoptimization happens
819 static bool should_reexecute_implied_by_bytecode(JVMState *jvms, bool is_anewarray) {
820 ciMethod* cur_method = jvms->method();
821 int cur_bci = jvms->bci();
822 if (cur_method != NULL && cur_bci != InvocationEntryBci) {
823 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci);
824 return Interpreter::bytecode_should_reexecute(code) ||
825 is_anewarray && code == Bytecodes::_multianewarray;
826 // Reexecute _multianewarray bytecode which was replaced with
827 // sequence of [a]newarray. See Parse::do_multianewarray().
828 //
829 // Note: interpreter should not have it set since this optimization
830 // is limited by dimensions and guarded by flag so in some cases
831 // multianewarray() runtime calls will be generated and
832 // the bytecode should not be reexecutes (stack will not be reset).
833 } else
834 return false;
835 }
836
837 // Helper function for adding JVMState and debug information to node
838 void GraphKit::add_safepoint_edges(SafePointNode* call, bool must_throw) {
839 // Add the safepoint edges to the call (or other safepoint).
840
841 // Make sure dead locals are set to top. This
842 // should help register allocation time and cut down on the size
843 // of the deoptimization information.
844 assert(dead_locals_are_killed(), "garbage in debug info before safepoint");
845
846 // Walk the inline list to fill in the correct set of JVMState's
847 // Also fill in the associated edges for each JVMState.
848
849 // If the bytecode needs to be reexecuted we need to put
850 // the arguments back on the stack.
851 const bool should_reexecute = jvms()->should_reexecute();
852 JVMState* youngest_jvms = should_reexecute ? sync_jvms_for_reexecute() : sync_jvms();
853
854 // NOTE: set_bci (called from sync_jvms) might reset the reexecute bit to
855 // undefined if the bci is different. This is normal for Parse but it
856 // should not happen for LibraryCallKit because only one bci is processed.
857 assert(!is_LibraryCallKit() || (jvms()->should_reexecute() == should_reexecute),
858 "in LibraryCallKit the reexecute bit should not change");
859
860 // If we are guaranteed to throw, we can prune everything but the
861 // input to the current bytecode.
862 bool can_prune_locals = false;
863 uint stack_slots_not_pruned = 0;
864 int inputs = 0, depth = 0;
865 if (must_throw) {
866 assert(method() == youngest_jvms->method(), "sanity");
867 if (compute_stack_effects(inputs, depth)) {
868 can_prune_locals = true;
869 stack_slots_not_pruned = inputs;
870 }
871 }
872
873 if (env()->should_retain_local_variables()) {
874 // At any safepoint, this method can get breakpointed, which would
875 // then require an immediate deoptimization.
876 can_prune_locals = false; // do not prune locals
877 stack_slots_not_pruned = 0;
878 }
879
880 // do not scribble on the input jvms
881 JVMState* out_jvms = youngest_jvms->clone_deep(C);
882 call->set_jvms(out_jvms); // Start jvms list for call node
883
884 // For a known set of bytecodes, the interpreter should reexecute them if
885 // deoptimization happens. We set the reexecute state for them here
886 if (out_jvms->is_reexecute_undefined() && //don't change if already specified
887 should_reexecute_implied_by_bytecode(out_jvms, call->is_AllocateArray())) {
888 out_jvms->set_should_reexecute(true); //NOTE: youngest_jvms not changed
889 }
890
891 // Presize the call:
892 DEBUG_ONLY(uint non_debug_edges = call->req());
893 call->add_req_batch(top(), youngest_jvms->debug_depth());
894 assert(call->req() == non_debug_edges + youngest_jvms->debug_depth(), "");
895
896 // Set up edges so that the call looks like this:
897 // Call [state:] ctl io mem fptr retadr
898 // [parms:] parm0 ... parmN
899 // [root:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
900 // [...mid:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN [...]
901 // [young:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
902 // Note that caller debug info precedes callee debug info.
903
904 // Fill pointer walks backwards from "young:" to "root:" in the diagram above:
905 uint debug_ptr = call->req();
906
907 // Loop over the map input edges associated with jvms, add them
908 // to the call node, & reset all offsets to match call node array.
909 for (JVMState* in_jvms = youngest_jvms; in_jvms != NULL; ) {
910 uint debug_end = debug_ptr;
911 uint debug_start = debug_ptr - in_jvms->debug_size();
912 debug_ptr = debug_start; // back up the ptr
913
914 uint p = debug_start; // walks forward in [debug_start, debug_end)
915 uint j, k, l;
916 SafePointNode* in_map = in_jvms->map();
917 out_jvms->set_map(call);
918
919 if (can_prune_locals) {
920 assert(in_jvms->method() == out_jvms->method(), "sanity");
921 // If the current throw can reach an exception handler in this JVMS,
922 // then we must keep everything live that can reach that handler.
923 // As a quick and dirty approximation, we look for any handlers at all.
924 if (in_jvms->method()->has_exception_handlers()) {
925 can_prune_locals = false;
926 }
927 }
928
929 // Add the Locals
930 k = in_jvms->locoff();
931 l = in_jvms->loc_size();
932 out_jvms->set_locoff(p);
933 if (!can_prune_locals) {
934 for (j = 0; j < l; j++)
935 call->set_req(p++, in_map->in(k+j));
936 } else {
937 p += l; // already set to top above by add_req_batch
938 }
939
940 // Add the Expression Stack
941 k = in_jvms->stkoff();
942 l = in_jvms->sp();
943 out_jvms->set_stkoff(p);
944 if (!can_prune_locals) {
945 for (j = 0; j < l; j++)
946 call->set_req(p++, in_map->in(k+j));
947 } else if (can_prune_locals && stack_slots_not_pruned != 0) {
948 // Divide stack into {S0,...,S1}, where S0 is set to top.
949 uint s1 = stack_slots_not_pruned;
950 stack_slots_not_pruned = 0; // for next iteration
951 if (s1 > l) s1 = l;
952 uint s0 = l - s1;
953 p += s0; // skip the tops preinstalled by add_req_batch
954 for (j = s0; j < l; j++)
955 call->set_req(p++, in_map->in(k+j));
956 } else {
957 p += l; // already set to top above by add_req_batch
958 }
959
960 // Add the Monitors
961 k = in_jvms->monoff();
962 l = in_jvms->mon_size();
963 out_jvms->set_monoff(p);
964 for (j = 0; j < l; j++)
965 call->set_req(p++, in_map->in(k+j));
966
967 // Copy any scalar object fields.
968 k = in_jvms->scloff();
969 l = in_jvms->scl_size();
970 out_jvms->set_scloff(p);
971 for (j = 0; j < l; j++)
972 call->set_req(p++, in_map->in(k+j));
973
974 // Finish the new jvms.
975 out_jvms->set_endoff(p);
976
977 assert(out_jvms->endoff() == debug_end, "fill ptr must match");
978 assert(out_jvms->depth() == in_jvms->depth(), "depth must match");
979 assert(out_jvms->loc_size() == in_jvms->loc_size(), "size must match");
980 assert(out_jvms->mon_size() == in_jvms->mon_size(), "size must match");
981 assert(out_jvms->scl_size() == in_jvms->scl_size(), "size must match");
982 assert(out_jvms->debug_size() == in_jvms->debug_size(), "size must match");
983
984 // Update the two tail pointers in parallel.
985 out_jvms = out_jvms->caller();
986 in_jvms = in_jvms->caller();
987 }
988
989 assert(debug_ptr == non_debug_edges, "debug info must fit exactly");
990
991 // Test the correctness of JVMState::debug_xxx accessors:
992 assert(call->jvms()->debug_start() == non_debug_edges, "");
993 assert(call->jvms()->debug_end() == call->req(), "");
994 assert(call->jvms()->debug_depth() == call->req() - non_debug_edges, "");
995 }
996
997 bool GraphKit::compute_stack_effects(int& inputs, int& depth) {
998 Bytecodes::Code code = java_bc();
999 if (code == Bytecodes::_wide) {
1000 code = method()->java_code_at_bci(bci() + 1);
1001 }
1002
1003 BasicType rtype = T_ILLEGAL;
1004 int rsize = 0;
1005
1006 if (code != Bytecodes::_illegal) {
1007 depth = Bytecodes::depth(code); // checkcast=0, athrow=-1
1008 rtype = Bytecodes::result_type(code); // checkcast=P, athrow=V
1009 if (rtype < T_CONFLICT)
1010 rsize = type2size[rtype];
1011 }
1012
1013 switch (code) {
1014 case Bytecodes::_illegal:
1015 return false;
1016
1017 case Bytecodes::_ldc:
1018 case Bytecodes::_ldc_w:
1019 case Bytecodes::_ldc2_w:
1020 inputs = 0;
1021 break;
1022
1023 case Bytecodes::_dup: inputs = 1; break;
1024 case Bytecodes::_dup_x1: inputs = 2; break;
1025 case Bytecodes::_dup_x2: inputs = 3; break;
1026 case Bytecodes::_dup2: inputs = 2; break;
1027 case Bytecodes::_dup2_x1: inputs = 3; break;
1028 case Bytecodes::_dup2_x2: inputs = 4; break;
1029 case Bytecodes::_swap: inputs = 2; break;
1030 case Bytecodes::_arraylength: inputs = 1; break;
1031
1032 case Bytecodes::_getstatic:
1033 case Bytecodes::_putstatic:
1034 case Bytecodes::_getfield:
1035 case Bytecodes::_putfield:
1036 {
1037 bool ignored_will_link;
1038 ciField* field = method()->get_field_at_bci(bci(), ignored_will_link);
1039 int size = field->type()->size();
1040 bool is_get = (depth >= 0), is_static = (depth & 1);
1041 inputs = (is_static ? 0 : 1);
1042 if (is_get) {
1043 depth = size - inputs;
1044 } else {
1045 inputs += size; // putxxx pops the value from the stack
1046 depth = - inputs;
1047 }
1048 }
1049 break;
1050
1051 case Bytecodes::_invokevirtual:
1052 case Bytecodes::_invokespecial:
1053 case Bytecodes::_invokestatic:
1054 case Bytecodes::_invokedynamic:
1055 case Bytecodes::_invokeinterface:
1056 {
1057 bool ignored_will_link;
1058 ciSignature* declared_signature = NULL;
1059 ciMethod* ignored_callee = method()->get_method_at_bci(bci(), ignored_will_link, &declared_signature);
1060 assert(declared_signature != NULL, "cannot be null");
1061 inputs = declared_signature->arg_size_for_bc(code);
1062 int size = declared_signature->return_type()->size();
1063 depth = size - inputs;
1064 }
1065 break;
1066
1067 case Bytecodes::_multianewarray:
1068 {
1069 ciBytecodeStream iter(method());
1070 iter.reset_to_bci(bci());
1071 iter.next();
1072 inputs = iter.get_dimensions();
1073 assert(rsize == 1, "");
1074 depth = rsize - inputs;
1075 }
1076 break;
1077
1078 case Bytecodes::_ireturn:
1079 case Bytecodes::_lreturn:
1080 case Bytecodes::_freturn:
1081 case Bytecodes::_dreturn:
1082 case Bytecodes::_areturn:
1083 assert(rsize = -depth, "");
1084 inputs = rsize;
1085 break;
1086
1087 case Bytecodes::_jsr:
1088 case Bytecodes::_jsr_w:
1089 inputs = 0;
1090 depth = 1; // S.B. depth=1, not zero
1091 break;
1092
1093 default:
1094 // bytecode produces a typed result
1095 inputs = rsize - depth;
1096 assert(inputs >= 0, "");
1097 break;
1098 }
1099
1100 #ifdef ASSERT
1101 // spot check
1102 int outputs = depth + inputs;
1103 assert(outputs >= 0, "sanity");
1104 switch (code) {
1105 case Bytecodes::_checkcast: assert(inputs == 1 && outputs == 1, ""); break;
1106 case Bytecodes::_athrow: assert(inputs == 1 && outputs == 0, ""); break;
1107 case Bytecodes::_aload_0: assert(inputs == 0 && outputs == 1, ""); break;
1108 case Bytecodes::_return: assert(inputs == 0 && outputs == 0, ""); break;
1109 case Bytecodes::_drem: assert(inputs == 4 && outputs == 2, ""); break;
1110 }
1111 #endif //ASSERT
1112
1113 return true;
1114 }
1115
1116
1117
1118 //------------------------------basic_plus_adr---------------------------------
1119 Node* GraphKit::basic_plus_adr(Node* base, Node* ptr, Node* offset) {
1120 // short-circuit a common case
1121 if (offset == intcon(0)) return ptr;
1122 return _gvn.transform( new AddPNode(base, ptr, offset) );
1123 }
1124
1125 Node* GraphKit::ConvI2L(Node* offset) {
1126 // short-circuit a common case
1127 jint offset_con = find_int_con(offset, Type::OffsetBot);
1128 if (offset_con != Type::OffsetBot) {
1129 return longcon((jlong) offset_con);
1130 }
1131 return _gvn.transform( new ConvI2LNode(offset));
1132 }
1133
1134 Node* GraphKit::ConvI2UL(Node* offset) {
1135 juint offset_con = (juint) find_int_con(offset, Type::OffsetBot);
1136 if (offset_con != (juint) Type::OffsetBot) {
1137 return longcon((julong) offset_con);
1138 }
1139 Node* conv = _gvn.transform( new ConvI2LNode(offset));
1140 Node* mask = _gvn.transform(ConLNode::make((julong) max_juint));
1141 return _gvn.transform( new AndLNode(conv, mask) );
1142 }
1143
1144 Node* GraphKit::ConvL2I(Node* offset) {
1145 // short-circuit a common case
1146 jlong offset_con = find_long_con(offset, (jlong)Type::OffsetBot);
1147 if (offset_con != (jlong)Type::OffsetBot) {
1148 return intcon((int) offset_con);
1149 }
1150 return _gvn.transform( new ConvL2INode(offset));
1151 }
1152
1153 //-------------------------load_object_klass-----------------------------------
1154 Node* GraphKit::load_object_klass(Node* obj) {
1155 // Special-case a fresh allocation to avoid building nodes:
1156 Node* akls = AllocateNode::Ideal_klass(obj, &_gvn);
1157 if (akls != NULL) return akls;
1158 if (ShenandoahVerifyReadsToFromSpace) {
1159 obj = shenandoah_read_barrier(obj);
1160 }
1161 Node* k_adr = basic_plus_adr(obj, oopDesc::klass_offset_in_bytes());
1162 return _gvn.transform(LoadKlassNode::make(_gvn, NULL, immutable_memory(), k_adr, TypeInstPtr::KLASS));
1163 }
1164
1165 //-------------------------load_array_length-----------------------------------
1166 Node* GraphKit::load_array_length(Node* array) {
1167 // Special-case a fresh allocation to avoid building nodes:
1168 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(array, &_gvn);
1169 Node *alen;
1170 if (alloc == NULL) {
1171 if (ShenandoahVerifyReadsToFromSpace) {
1172 array = shenandoah_read_barrier(array);
1173 }
1174
1175 Node *r_adr = basic_plus_adr(array, arrayOopDesc::length_offset_in_bytes());
1176 alen = _gvn.transform( new LoadRangeNode(0, immutable_memory(), r_adr, TypeInt::POS));
1177 } else {
1178 alen = alloc->Ideal_length();
1179 Node* ccast = alloc->make_ideal_length(_gvn.type(array)->is_oopptr(), &_gvn);
1180 if (ccast != alen) {
1181 alen = _gvn.transform(ccast);
1182 }
1183 }
1184 return alen;
1185 }
1186
1187 //------------------------------do_null_check----------------------------------
1188 // Helper function to do a NULL pointer check. Returned value is
1189 // the incoming address with NULL casted away. You are allowed to use the
1190 // not-null value only if you are control dependent on the test.
1191 extern int explicit_null_checks_inserted,
1192 explicit_null_checks_elided;
1193 Node* GraphKit::null_check_common(Node* value, BasicType type,
1194 // optional arguments for variations:
1195 bool assert_null,
1196 Node* *null_control,
1197 bool speculative) {
1198 assert(!assert_null || null_control == NULL, "not both at once");
1199 if (stopped()) return top();
1200 if (!GenerateCompilerNullChecks && !assert_null && null_control == NULL) {
1201 // For some performance testing, we may wish to suppress null checking.
1202 value = cast_not_null(value); // Make it appear to be non-null (4962416).
1203 return value;
1204 }
1205 explicit_null_checks_inserted++;
1206
1207 // Construct NULL check
1208 Node *chk = NULL;
1209 switch(type) {
1210 case T_LONG : chk = new CmpLNode(value, _gvn.zerocon(T_LONG)); break;
1211 case T_INT : chk = new CmpINode(value, _gvn.intcon(0)); break;
1212 case T_ARRAY : // fall through
1213 type = T_OBJECT; // simplify further tests
1214 case T_OBJECT : {
1215 const Type *t = _gvn.type( value );
1216
1217 const TypeOopPtr* tp = t->isa_oopptr();
1218 if (tp != NULL && tp->klass() != NULL && !tp->klass()->is_loaded()
1219 // Only for do_null_check, not any of its siblings:
1220 && !assert_null && null_control == NULL) {
1221 // Usually, any field access or invocation on an unloaded oop type
1222 // will simply fail to link, since the statically linked class is
1223 // likely also to be unloaded. However, in -Xcomp mode, sometimes
1224 // the static class is loaded but the sharper oop type is not.
1225 // Rather than checking for this obscure case in lots of places,
1226 // we simply observe that a null check on an unloaded class
1227 // will always be followed by a nonsense operation, so we
1228 // can just issue the uncommon trap here.
1229 // Our access to the unloaded class will only be correct
1230 // after it has been loaded and initialized, which requires
1231 // a trip through the interpreter.
1232 #ifndef PRODUCT
1233 if (WizardMode) { tty->print("Null check of unloaded "); tp->klass()->print(); tty->cr(); }
1234 #endif
1235 uncommon_trap(Deoptimization::Reason_unloaded,
1236 Deoptimization::Action_reinterpret,
1237 tp->klass(), "!loaded");
1238 return top();
1239 }
1240
1241 if (assert_null) {
1242 // See if the type is contained in NULL_PTR.
1243 // If so, then the value is already null.
1244 if (t->higher_equal(TypePtr::NULL_PTR)) {
1245 explicit_null_checks_elided++;
1246 return value; // Elided null assert quickly!
1247 }
1248 } else {
1249 // See if mixing in the NULL pointer changes type.
1250 // If so, then the NULL pointer was not allowed in the original
1251 // type. In other words, "value" was not-null.
1252 if (t->meet(TypePtr::NULL_PTR) != t->remove_speculative()) {
1253 // same as: if (!TypePtr::NULL_PTR->higher_equal(t)) ...
1254 explicit_null_checks_elided++;
1255 return value; // Elided null check quickly!
1256 }
1257 }
1258 chk = new CmpPNode( value, null() );
1259 break;
1260 }
1261
1262 default:
1263 fatal(err_msg_res("unexpected type: %s", type2name(type)));
1264 }
1265 assert(chk != NULL, "sanity check");
1266 chk = _gvn.transform(chk);
1267
1268 BoolTest::mask btest = assert_null ? BoolTest::eq : BoolTest::ne;
1269 BoolNode *btst = new BoolNode( chk, btest);
1270 Node *tst = _gvn.transform( btst );
1271
1272 //-----------
1273 // if peephole optimizations occurred, a prior test existed.
1274 // If a prior test existed, maybe it dominates as we can avoid this test.
1275 if (tst != btst && type == T_OBJECT) {
1276 // At this point we want to scan up the CFG to see if we can
1277 // find an identical test (and so avoid this test altogether).
1278 Node *cfg = control();
1279 int depth = 0;
1280 while( depth < 16 ) { // Limit search depth for speed
1281 if( cfg->Opcode() == Op_IfTrue &&
1282 cfg->in(0)->in(1) == tst ) {
1283 // Found prior test. Use "cast_not_null" to construct an identical
1284 // CastPP (and hence hash to) as already exists for the prior test.
1285 // Return that casted value.
1286 if (assert_null) {
1287 replace_in_map(value, null());
1288 return null(); // do not issue the redundant test
1289 }
1290 Node *oldcontrol = control();
1291 set_control(cfg);
1292 Node *res = cast_not_null(value);
1293 set_control(oldcontrol);
1294 explicit_null_checks_elided++;
1295 return res;
1296 }
1297 cfg = IfNode::up_one_dom(cfg, /*linear_only=*/ true);
1298 if (cfg == NULL) break; // Quit at region nodes
1299 depth++;
1300 }
1301 }
1302
1303 //-----------
1304 // Branch to failure if null
1305 float ok_prob = PROB_MAX; // a priori estimate: nulls never happen
1306 Deoptimization::DeoptReason reason;
1307 if (assert_null) {
1308 reason = Deoptimization::Reason_null_assert;
1309 } else if (type == T_OBJECT) {
1310 reason = Deoptimization::reason_null_check(speculative);
1311 } else {
1312 reason = Deoptimization::Reason_div0_check;
1313 }
1314 // %%% Since Reason_unhandled is not recorded on a per-bytecode basis,
1315 // ciMethodData::has_trap_at will return a conservative -1 if any
1316 // must-be-null assertion has failed. This could cause performance
1317 // problems for a method after its first do_null_assert failure.
1318 // Consider using 'Reason_class_check' instead?
1319
1320 // To cause an implicit null check, we set the not-null probability
1321 // to the maximum (PROB_MAX). For an explicit check the probability
1322 // is set to a smaller value.
1323 if (null_control != NULL || too_many_traps(reason)) {
1324 // probability is less likely
1325 ok_prob = PROB_LIKELY_MAG(3);
1326 } else if (!assert_null &&
1327 (ImplicitNullCheckThreshold > 0) &&
1328 method() != NULL &&
1329 (method()->method_data()->trap_count(reason)
1330 >= (uint)ImplicitNullCheckThreshold)) {
1331 ok_prob = PROB_LIKELY_MAG(3);
1332 }
1333
1334 if (null_control != NULL) {
1335 IfNode* iff = create_and_map_if(control(), tst, ok_prob, COUNT_UNKNOWN);
1336 Node* null_true = _gvn.transform( new IfFalseNode(iff));
1337 set_control( _gvn.transform( new IfTrueNode(iff)));
1338 if (null_true == top())
1339 explicit_null_checks_elided++;
1340 (*null_control) = null_true;
1341 } else {
1342 BuildCutout unless(this, tst, ok_prob);
1343 // Check for optimizer eliding test at parse time
1344 if (stopped()) {
1345 // Failure not possible; do not bother making uncommon trap.
1346 explicit_null_checks_elided++;
1347 } else if (assert_null) {
1348 uncommon_trap(reason,
1349 Deoptimization::Action_make_not_entrant,
1350 NULL, "assert_null");
1351 } else {
1352 replace_in_map(value, zerocon(type));
1353 builtin_throw(reason);
1354 }
1355 }
1356
1357 // Must throw exception, fall-thru not possible?
1358 if (stopped()) {
1359 return top(); // No result
1360 }
1361
1362 if (assert_null) {
1363 // Cast obj to null on this path.
1364 replace_in_map(value, zerocon(type));
1365 return zerocon(type);
1366 }
1367
1368 // Cast obj to not-null on this path, if there is no null_control.
1369 // (If there is a null_control, a non-null value may come back to haunt us.)
1370 if (type == T_OBJECT) {
1371 Node* cast = cast_not_null(value, false);
1372 if (null_control == NULL || (*null_control) == top())
1373 replace_in_map(value, cast);
1374 value = cast;
1375 }
1376
1377 return value;
1378 }
1379
1380
1381 //------------------------------cast_not_null----------------------------------
1382 // Cast obj to not-null on this path
1383 Node* GraphKit::cast_not_null(Node* obj, bool do_replace_in_map) {
1384 const Type *t = _gvn.type(obj);
1385 const Type *t_not_null = t->join_speculative(TypePtr::NOTNULL);
1386 // Object is already not-null?
1387 if( t == t_not_null ) return obj;
1388
1389 Node *cast = new CastPPNode(obj,t_not_null);
1390 cast->init_req(0, control());
1391 cast = _gvn.transform( cast );
1392
1393 // Scan for instances of 'obj' in the current JVM mapping.
1394 // These instances are known to be not-null after the test.
1395 if (do_replace_in_map)
1396 replace_in_map(obj, cast);
1397
1398 return cast; // Return casted value
1399 }
1400
1401
1402 //--------------------------replace_in_map-------------------------------------
1403 void GraphKit::replace_in_map(Node* old, Node* neww) {
1404 if (old == neww) {
1405 return;
1406 }
1407
1408 map()->replace_edge(old, neww);
1409
1410 // Note: This operation potentially replaces any edge
1411 // on the map. This includes locals, stack, and monitors
1412 // of the current (innermost) JVM state.
1413
1414 // don't let inconsistent types from profiling escape this
1415 // method
1416
1417 const Type* told = _gvn.type(old);
1418 const Type* tnew = _gvn.type(neww);
1419
1420 if (!tnew->higher_equal(told)) {
1421 return;
1422 }
1423
1424 map()->record_replaced_node(old, neww);
1425 }
1426
1427
1428 //=============================================================================
1429 //--------------------------------memory---------------------------------------
1430 Node* GraphKit::memory(uint alias_idx) {
1431 MergeMemNode* mem = merged_memory();
1432 Node* p = mem->memory_at(alias_idx);
1433 _gvn.set_type(p, Type::MEMORY); // must be mapped
1434 return p;
1435 }
1436
1437 //-----------------------------reset_memory------------------------------------
1438 Node* GraphKit::reset_memory() {
1439 Node* mem = map()->memory();
1440 // do not use this node for any more parsing!
1441 debug_only( map()->set_memory((Node*)NULL) );
1442 return _gvn.transform( mem );
1443 }
1444
1445 //------------------------------set_all_memory---------------------------------
1446 void GraphKit::set_all_memory(Node* newmem) {
1447 Node* mergemem = MergeMemNode::make(newmem);
1448 gvn().set_type_bottom(mergemem);
1449 map()->set_memory(mergemem);
1450 }
1451
1452 //------------------------------set_all_memory_call----------------------------
1453 void GraphKit::set_all_memory_call(Node* call, bool separate_io_proj) {
1454 Node* newmem = _gvn.transform( new ProjNode(call, TypeFunc::Memory, separate_io_proj) );
1455 set_all_memory(newmem);
1456 }
1457
1458 //=============================================================================
1459 //
1460 // parser factory methods for MemNodes
1461 //
1462 // These are layered on top of the factory methods in LoadNode and StoreNode,
1463 // and integrate with the parser's memory state and _gvn engine.
1464 //
1465
1466 // factory methods in "int adr_idx"
1467 Node* GraphKit::make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,
1468 int adr_idx,
1469 MemNode::MemOrd mo, LoadNode::ControlDependency control_dependency, bool require_atomic_access) {
1470 assert(adr_idx != Compile::AliasIdxTop, "use other make_load factory" );
1471 const TypePtr* adr_type = NULL; // debug-mode-only argument
1472 debug_only(adr_type = C->get_adr_type(adr_idx));
1473 Node* mem = memory(adr_idx);
1474 Node* ld;
1475 if (require_atomic_access && bt == T_LONG) {
1476 ld = LoadLNode::make_atomic(ctl, mem, adr, adr_type, t, mo, control_dependency);
1477 } else if (require_atomic_access && bt == T_DOUBLE) {
1478 ld = LoadDNode::make_atomic(ctl, mem, adr, adr_type, t, mo, control_dependency);
1479 } else {
1480 ld = LoadNode::make(_gvn, ctl, mem, adr, adr_type, t, bt, mo, control_dependency);
1481 }
1482 ld = _gvn.transform(ld);
1483 if ((bt == T_OBJECT) && C->do_escape_analysis() || C->eliminate_boxing()) {
1484 // Improve graph before escape analysis and boxing elimination.
1485 record_for_igvn(ld);
1486 }
1487 return ld;
1488 }
1489
1490 Node* GraphKit::store_to_memory(Node* ctl, Node* adr, Node *val, BasicType bt,
1491 int adr_idx,
1492 MemNode::MemOrd mo,
1493 bool require_atomic_access) {
1494 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1495 const TypePtr* adr_type = NULL;
1496 debug_only(adr_type = C->get_adr_type(adr_idx));
1497 Node *mem = memory(adr_idx);
1498 Node* st;
1499 if (require_atomic_access && bt == T_LONG) {
1500 st = StoreLNode::make_atomic(ctl, mem, adr, adr_type, val, mo);
1501 } else if (require_atomic_access && bt == T_DOUBLE) {
1502 st = StoreDNode::make_atomic(ctl, mem, adr, adr_type, val, mo);
1503 } else {
1504 st = StoreNode::make(_gvn, ctl, mem, adr, adr_type, val, bt, mo);
1505 }
1506 st = _gvn.transform(st);
1507 set_memory(st, adr_idx);
1508 // Back-to-back stores can only remove intermediate store with DU info
1509 // so push on worklist for optimizer.
1510 if (mem->req() > MemNode::Address && adr == mem->in(MemNode::Address))
1511 record_for_igvn(st);
1512
1513 return st;
1514 }
1515
1516
1517 void GraphKit::pre_barrier(bool do_load,
1518 Node* ctl,
1519 Node* obj,
1520 Node* adr,
1521 uint adr_idx,
1522 Node* val,
1523 const TypeOopPtr* val_type,
1524 Node* pre_val,
1525 BasicType bt) {
1526
1527 BarrierSet* bs = Universe::heap()->barrier_set();
1528 set_control(ctl);
1529 switch (bs->kind()) {
1530 case BarrierSet::G1SATBCTLogging:
1531 case BarrierSet::ShenandoahBarrierSet:
1532 g1_write_barrier_pre(do_load, obj, adr, adr_idx, val, val_type, pre_val, bt);
1533 break;
1534
1535 case BarrierSet::CardTableForRS:
1536 case BarrierSet::CardTableExtension:
1537 case BarrierSet::ModRef:
1538 break;
1539
1540 default :
1541 ShouldNotReachHere();
1542
1543 }
1544 }
1545
1546 bool GraphKit::can_move_pre_barrier() const {
1547 BarrierSet* bs = Universe::heap()->barrier_set();
1548 switch (bs->kind()) {
1549 case BarrierSet::G1SATBCTLogging:
1550 case BarrierSet::ShenandoahBarrierSet:
1551 return true; // Can move it if no safepoint
1552
1553 case BarrierSet::CardTableForRS:
1554 case BarrierSet::CardTableExtension:
1555 case BarrierSet::ModRef:
1556 return true; // There is no pre-barrier
1557
1558 default :
1559 ShouldNotReachHere();
1560 }
1561 return false;
1562 }
1563
1564 void GraphKit::post_barrier(Node* ctl,
1565 Node* store,
1566 Node* obj,
1567 Node* adr,
1568 uint adr_idx,
1569 Node* val,
1570 BasicType bt,
1571 bool use_precise) {
1572 BarrierSet* bs = Universe::heap()->barrier_set();
1573 set_control(ctl);
1574 switch (bs->kind()) {
1575 case BarrierSet::G1SATBCTLogging:
1576 g1_write_barrier_post(store, obj, adr, adr_idx, val, bt, use_precise);
1577 break;
1578
1579 case BarrierSet::CardTableForRS:
1580 case BarrierSet::CardTableExtension:
1581 write_barrier_post(store, obj, adr, adr_idx, val, use_precise);
1582 break;
1583
1584 case BarrierSet::ModRef:
1585 case BarrierSet::ShenandoahBarrierSet:
1586 break;
1587
1588 default :
1589 ShouldNotReachHere();
1590
1591 }
1592 }
1593
1594 Node* GraphKit::store_oop(Node* ctl,
1595 Node* obj,
1596 Node* adr,
1597 const TypePtr* adr_type,
1598 Node* val,
1599 const TypeOopPtr* val_type,
1600 BasicType bt,
1601 bool use_precise,
1602 MemNode::MemOrd mo) {
1603 // Transformation of a value which could be NULL pointer (CastPP #NULL)
1604 // could be delayed during Parse (for example, in adjust_map_after_if()).
1605 // Execute transformation here to avoid barrier generation in such case.
1606 if (_gvn.type(val) == TypePtr::NULL_PTR)
1607 val = _gvn.makecon(TypePtr::NULL_PTR);
1608
1609 set_control(ctl);
1610 if (stopped()) return top(); // Dead path ?
1611
1612 assert(bt == T_OBJECT, "sanity");
1613 assert(val != NULL, "not dead path");
1614 uint adr_idx = C->get_alias_index(adr_type);
1615 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1616
1617 pre_barrier(true /* do_load */,
1618 control(), obj, adr, adr_idx, val, val_type,
1619 NULL /* pre_val */,
1620 bt);
1621
1622 Node* store = store_to_memory(control(), adr, val, bt, adr_idx, mo);
1623 post_barrier(control(), store, obj, adr, adr_idx, val, bt, use_precise);
1624 return store;
1625 }
1626
1627 // Could be an array or object we don't know at compile time (unsafe ref.)
1628 Node* GraphKit::store_oop_to_unknown(Node* ctl,
1629 Node* obj, // containing obj
1630 Node* adr, // actual adress to store val at
1631 const TypePtr* adr_type,
1632 Node* val,
1633 BasicType bt,
1634 MemNode::MemOrd mo) {
1635 Compile::AliasType* at = C->alias_type(adr_type);
1636 const TypeOopPtr* val_type = NULL;
1637 if (adr_type->isa_instptr()) {
1638 if (at->field() != NULL) {
1639 // known field. This code is a copy of the do_put_xxx logic.
1640 ciField* field = at->field();
1641 if (!field->type()->is_loaded()) {
1642 val_type = TypeInstPtr::BOTTOM;
1643 } else {
1644 val_type = TypeOopPtr::make_from_klass(field->type()->as_klass());
1645 }
1646 }
1647 } else if (adr_type->isa_aryptr()) {
1648 val_type = adr_type->is_aryptr()->elem()->make_oopptr();
1649 }
1650 if (val_type == NULL) {
1651 val_type = TypeInstPtr::BOTTOM;
1652 }
1653 return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, true, mo);
1654 }
1655
1656
1657 //-------------------------array_element_address-------------------------
1658 Node* GraphKit::array_element_address(Node* ary, Node* idx, BasicType elembt,
1659 const TypeInt* sizetype) {
1660 uint shift = exact_log2(type2aelembytes(elembt));
1661 uint header = arrayOopDesc::base_offset_in_bytes(elembt);
1662
1663 // short-circuit a common case (saves lots of confusing waste motion)
1664 jint idx_con = find_int_con(idx, -1);
1665 if (idx_con >= 0) {
1666 intptr_t offset = header + ((intptr_t)idx_con << shift);
1667 return basic_plus_adr(ary, offset);
1668 }
1669
1670 // must be correct type for alignment purposes
1671 Node* base = basic_plus_adr(ary, header);
1672 idx = Compile::conv_I2X_index(&_gvn, idx, sizetype);
1673 Node* scale = _gvn.transform( new LShiftXNode(idx, intcon(shift)) );
1674 return basic_plus_adr(ary, base, scale);
1675 }
1676
1677 //-------------------------load_array_element-------------------------
1678 Node* GraphKit::load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype) {
1679 const Type* elemtype = arytype->elem();
1680 BasicType elembt = elemtype->array_element_basic_type();
1681 Node* adr = array_element_address(ary, idx, elembt, arytype->size());
1682 Node* ld = make_load(ctl, adr, elemtype, elembt, arytype, MemNode::unordered);
1683 return ld;
1684 }
1685
1686 //-------------------------set_arguments_for_java_call-------------------------
1687 // Arguments (pre-popped from the stack) are taken from the JVMS.
1688 void GraphKit::set_arguments_for_java_call(CallJavaNode* call) {
1689 // Add the call arguments:
1690 uint nargs = call->method()->arg_size();
1691 for (uint i = 0; i < nargs; i++) {
1692 Node* arg = argument(i);
1693 if (ShenandoahVerifyReadsToFromSpace && call->is_CallDynamicJava() && i == 0) {
1694 arg = shenandoah_read_barrier(arg);
1695 }
1696 call->init_req(i + TypeFunc::Parms, arg);
1697 }
1698 }
1699
1700 //---------------------------set_edges_for_java_call---------------------------
1701 // Connect a newly created call into the current JVMS.
1702 // A return value node (if any) is returned from set_edges_for_java_call.
1703 void GraphKit::set_edges_for_java_call(CallJavaNode* call, bool must_throw, bool separate_io_proj) {
1704
1705 // Add the predefined inputs:
1706 call->init_req( TypeFunc::Control, control() );
1707 call->init_req( TypeFunc::I_O , i_o() );
1708 call->init_req( TypeFunc::Memory , reset_memory() );
1709 call->init_req( TypeFunc::FramePtr, frameptr() );
1710 call->init_req( TypeFunc::ReturnAdr, top() );
1711
1712 add_safepoint_edges(call, must_throw);
1713
1714 Node* xcall = _gvn.transform(call);
1715
1716 if (xcall == top()) {
1717 set_control(top());
1718 return;
1719 }
1720 assert(xcall == call, "call identity is stable");
1721
1722 // Re-use the current map to produce the result.
1723
1724 set_control(_gvn.transform(new ProjNode(call, TypeFunc::Control)));
1725 set_i_o( _gvn.transform(new ProjNode(call, TypeFunc::I_O , separate_io_proj)));
1726 set_all_memory_call(xcall, separate_io_proj);
1727
1728 //return xcall; // no need, caller already has it
1729 }
1730
1731 Node* GraphKit::set_results_for_java_call(CallJavaNode* call, bool separate_io_proj) {
1732 if (stopped()) return top(); // maybe the call folded up?
1733
1734 // Capture the return value, if any.
1735 Node* ret;
1736 if (call->method() == NULL ||
1737 call->method()->return_type()->basic_type() == T_VOID)
1738 ret = top();
1739 else ret = _gvn.transform(new ProjNode(call, TypeFunc::Parms));
1740
1741 // Note: Since any out-of-line call can produce an exception,
1742 // we always insert an I_O projection from the call into the result.
1743
1744 make_slow_call_ex(call, env()->Throwable_klass(), separate_io_proj);
1745
1746 if (separate_io_proj) {
1747 // The caller requested separate projections be used by the fall
1748 // through and exceptional paths, so replace the projections for
1749 // the fall through path.
1750 set_i_o(_gvn.transform( new ProjNode(call, TypeFunc::I_O) ));
1751 set_all_memory(_gvn.transform( new ProjNode(call, TypeFunc::Memory) ));
1752 }
1753 return ret;
1754 }
1755
1756 //--------------------set_predefined_input_for_runtime_call--------------------
1757 // Reading and setting the memory state is way conservative here.
1758 // The real problem is that I am not doing real Type analysis on memory,
1759 // so I cannot distinguish card mark stores from other stores. Across a GC
1760 // point the Store Barrier and the card mark memory has to agree. I cannot
1761 // have a card mark store and its barrier split across the GC point from
1762 // either above or below. Here I get that to happen by reading ALL of memory.
1763 // A better answer would be to separate out card marks from other memory.
1764 // For now, return the input memory state, so that it can be reused
1765 // after the call, if this call has restricted memory effects.
1766 Node* GraphKit::set_predefined_input_for_runtime_call(SafePointNode* call) {
1767 // Set fixed predefined input arguments
1768 Node* memory = reset_memory();
1769 call->init_req( TypeFunc::Control, control() );
1770 call->init_req( TypeFunc::I_O, top() ); // does no i/o
1771 call->init_req( TypeFunc::Memory, memory ); // may gc ptrs
1772 call->init_req( TypeFunc::FramePtr, frameptr() );
1773 call->init_req( TypeFunc::ReturnAdr, top() );
1774 return memory;
1775 }
1776
1777 //-------------------set_predefined_output_for_runtime_call--------------------
1778 // Set control and memory (not i_o) from the call.
1779 // If keep_mem is not NULL, use it for the output state,
1780 // except for the RawPtr output of the call, if hook_mem is TypeRawPtr::BOTTOM.
1781 // If hook_mem is NULL, this call produces no memory effects at all.
1782 // If hook_mem is a Java-visible memory slice (such as arraycopy operands),
1783 // then only that memory slice is taken from the call.
1784 // In the last case, we must put an appropriate memory barrier before
1785 // the call, so as to create the correct anti-dependencies on loads
1786 // preceding the call.
1787 void GraphKit::set_predefined_output_for_runtime_call(Node* call,
1788 Node* keep_mem,
1789 const TypePtr* hook_mem) {
1790 // no i/o
1791 set_control(_gvn.transform( new ProjNode(call,TypeFunc::Control) ));
1792 if (keep_mem) {
1793 // First clone the existing memory state
1794 set_all_memory(keep_mem);
1795 if (hook_mem != NULL) {
1796 // Make memory for the call
1797 Node* mem = _gvn.transform( new ProjNode(call, TypeFunc::Memory) );
1798 // Set the RawPtr memory state only. This covers all the heap top/GC stuff
1799 // We also use hook_mem to extract specific effects from arraycopy stubs.
1800 set_memory(mem, hook_mem);
1801 }
1802 // ...else the call has NO memory effects.
1803
1804 // Make sure the call advertises its memory effects precisely.
1805 // This lets us build accurate anti-dependences in gcm.cpp.
1806 assert(C->alias_type(call->adr_type()) == C->alias_type(hook_mem),
1807 "call node must be constructed correctly");
1808 } else {
1809 assert(hook_mem == NULL, "");
1810 // This is not a "slow path" call; all memory comes from the call.
1811 set_all_memory_call(call);
1812 }
1813 }
1814
1815
1816 // Replace the call with the current state of the kit.
1817 void GraphKit::replace_call(CallNode* call, Node* result, bool do_replaced_nodes) {
1818 JVMState* ejvms = NULL;
1819 if (has_exceptions()) {
1820 ejvms = transfer_exceptions_into_jvms();
1821 }
1822
1823 ReplacedNodes replaced_nodes = map()->replaced_nodes();
1824 ReplacedNodes replaced_nodes_exception;
1825 Node* ex_ctl = top();
1826
1827 SafePointNode* final_state = stop();
1828
1829 // Find all the needed outputs of this call
1830 CallProjections callprojs;
1831 call->extract_projections(&callprojs, true);
1832
1833 Node* init_mem = call->in(TypeFunc::Memory);
1834 Node* final_mem = final_state->in(TypeFunc::Memory);
1835 Node* final_ctl = final_state->in(TypeFunc::Control);
1836 Node* final_io = final_state->in(TypeFunc::I_O);
1837
1838 // Replace all the old call edges with the edges from the inlining result
1839 if (callprojs.fallthrough_catchproj != NULL) {
1840 C->gvn_replace_by(callprojs.fallthrough_catchproj, final_ctl);
1841 }
1842 if (callprojs.fallthrough_memproj != NULL) {
1843 if (final_mem->is_MergeMem()) {
1844 // Parser's exits MergeMem was not transformed but may be optimized
1845 final_mem = _gvn.transform(final_mem);
1846 }
1847 C->gvn_replace_by(callprojs.fallthrough_memproj, final_mem);
1848 }
1849 if (callprojs.fallthrough_ioproj != NULL) {
1850 C->gvn_replace_by(callprojs.fallthrough_ioproj, final_io);
1851 }
1852
1853 // Replace the result with the new result if it exists and is used
1854 if (callprojs.resproj != NULL && result != NULL) {
1855 C->gvn_replace_by(callprojs.resproj, result);
1856 }
1857
1858 if (ejvms == NULL) {
1859 // No exception edges to simply kill off those paths
1860 if (callprojs.catchall_catchproj != NULL) {
1861 C->gvn_replace_by(callprojs.catchall_catchproj, C->top());
1862 }
1863 if (callprojs.catchall_memproj != NULL) {
1864 C->gvn_replace_by(callprojs.catchall_memproj, C->top());
1865 }
1866 if (callprojs.catchall_ioproj != NULL) {
1867 C->gvn_replace_by(callprojs.catchall_ioproj, C->top());
1868 }
1869 // Replace the old exception object with top
1870 if (callprojs.exobj != NULL) {
1871 C->gvn_replace_by(callprojs.exobj, C->top());
1872 }
1873 } else {
1874 GraphKit ekit(ejvms);
1875
1876 // Load my combined exception state into the kit, with all phis transformed:
1877 SafePointNode* ex_map = ekit.combine_and_pop_all_exception_states();
1878 replaced_nodes_exception = ex_map->replaced_nodes();
1879
1880 Node* ex_oop = ekit.use_exception_state(ex_map);
1881
1882 if (callprojs.catchall_catchproj != NULL) {
1883 C->gvn_replace_by(callprojs.catchall_catchproj, ekit.control());
1884 ex_ctl = ekit.control();
1885 }
1886 if (callprojs.catchall_memproj != NULL) {
1887 C->gvn_replace_by(callprojs.catchall_memproj, ekit.reset_memory());
1888 }
1889 if (callprojs.catchall_ioproj != NULL) {
1890 C->gvn_replace_by(callprojs.catchall_ioproj, ekit.i_o());
1891 }
1892
1893 // Replace the old exception object with the newly created one
1894 if (callprojs.exobj != NULL) {
1895 C->gvn_replace_by(callprojs.exobj, ex_oop);
1896 }
1897 }
1898
1899 // Disconnect the call from the graph
1900 call->disconnect_inputs(NULL, C);
1901 C->gvn_replace_by(call, C->top());
1902
1903 // Clean up any MergeMems that feed other MergeMems since the
1904 // optimizer doesn't like that.
1905 if (final_mem->is_MergeMem()) {
1906 Node_List wl;
1907 for (SimpleDUIterator i(final_mem); i.has_next(); i.next()) {
1908 Node* m = i.get();
1909 if (m->is_MergeMem() && !wl.contains(m)) {
1910 wl.push(m);
1911 }
1912 }
1913 while (wl.size() > 0) {
1914 _gvn.transform(wl.pop());
1915 }
1916 }
1917
1918 if (callprojs.fallthrough_catchproj != NULL && !final_ctl->is_top() && do_replaced_nodes) {
1919 replaced_nodes.apply(C, final_ctl);
1920 }
1921 if (!ex_ctl->is_top() && do_replaced_nodes) {
1922 replaced_nodes_exception.apply(C, ex_ctl);
1923 }
1924 }
1925
1926
1927 //------------------------------increment_counter------------------------------
1928 // for statistics: increment a VM counter by 1
1929
1930 void GraphKit::increment_counter(address counter_addr) {
1931 Node* adr1 = makecon(TypeRawPtr::make(counter_addr));
1932 increment_counter(adr1);
1933 }
1934
1935 void GraphKit::increment_counter(Node* counter_addr) {
1936 int adr_type = Compile::AliasIdxRaw;
1937 Node* ctrl = control();
1938 Node* cnt = make_load(ctrl, counter_addr, TypeInt::INT, T_INT, adr_type, MemNode::unordered);
1939 Node* incr = _gvn.transform(new AddINode(cnt, _gvn.intcon(1)));
1940 store_to_memory(ctrl, counter_addr, incr, T_INT, adr_type, MemNode::unordered);
1941 }
1942
1943
1944 //------------------------------uncommon_trap----------------------------------
1945 // Bail out to the interpreter in mid-method. Implemented by calling the
1946 // uncommon_trap blob. This helper function inserts a runtime call with the
1947 // right debug info.
1948 void GraphKit::uncommon_trap(int trap_request,
1949 ciKlass* klass, const char* comment,
1950 bool must_throw,
1951 bool keep_exact_action) {
1952 if (failing()) stop();
1953 if (stopped()) return; // trap reachable?
1954
1955 // Note: If ProfileTraps is true, and if a deopt. actually
1956 // occurs here, the runtime will make sure an MDO exists. There is
1957 // no need to call method()->ensure_method_data() at this point.
1958
1959 // Set the stack pointer to the right value for reexecution:
1960 set_sp(reexecute_sp());
1961
1962 #ifdef ASSERT
1963 if (!must_throw) {
1964 // Make sure the stack has at least enough depth to execute
1965 // the current bytecode.
1966 int inputs, ignored_depth;
1967 if (compute_stack_effects(inputs, ignored_depth)) {
1968 assert(sp() >= inputs, err_msg_res("must have enough JVMS stack to execute %s: sp=%d, inputs=%d",
1969 Bytecodes::name(java_bc()), sp(), inputs));
1970 }
1971 }
1972 #endif
1973
1974 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
1975 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request);
1976
1977 switch (action) {
1978 case Deoptimization::Action_maybe_recompile:
1979 case Deoptimization::Action_reinterpret:
1980 // Temporary fix for 6529811 to allow virtual calls to be sure they
1981 // get the chance to go from mono->bi->mega
1982 if (!keep_exact_action &&
1983 Deoptimization::trap_request_index(trap_request) < 0 &&
1984 too_many_recompiles(reason)) {
1985 // This BCI is causing too many recompilations.
1986 if (C->log() != NULL) {
1987 C->log()->elem("observe that='trap_action_change' reason='%s' from='%s' to='none'",
1988 Deoptimization::trap_reason_name(reason),
1989 Deoptimization::trap_action_name(action));
1990 }
1991 action = Deoptimization::Action_none;
1992 trap_request = Deoptimization::make_trap_request(reason, action);
1993 } else {
1994 C->set_trap_can_recompile(true);
1995 }
1996 break;
1997 case Deoptimization::Action_make_not_entrant:
1998 C->set_trap_can_recompile(true);
1999 break;
2000 #ifdef ASSERT
2001 case Deoptimization::Action_none:
2002 case Deoptimization::Action_make_not_compilable:
2003 break;
2004 default:
2005 fatal(err_msg_res("unknown action %d: %s", action, Deoptimization::trap_action_name(action)));
2006 break;
2007 #endif
2008 }
2009
2010 if (TraceOptoParse) {
2011 char buf[100];
2012 tty->print_cr("Uncommon trap %s at bci:%d",
2013 Deoptimization::format_trap_request(buf, sizeof(buf),
2014 trap_request), bci());
2015 }
2016
2017 CompileLog* log = C->log();
2018 if (log != NULL) {
2019 int kid = (klass == NULL)? -1: log->identify(klass);
2020 log->begin_elem("uncommon_trap bci='%d'", bci());
2021 char buf[100];
2022 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
2023 trap_request));
2024 if (kid >= 0) log->print(" klass='%d'", kid);
2025 if (comment != NULL) log->print(" comment='%s'", comment);
2026 log->end_elem();
2027 }
2028
2029 // Make sure any guarding test views this path as very unlikely
2030 Node *i0 = control()->in(0);
2031 if (i0 != NULL && i0->is_If()) { // Found a guarding if test?
2032 IfNode *iff = i0->as_If();
2033 float f = iff->_prob; // Get prob
2034 if (control()->Opcode() == Op_IfTrue) {
2035 if (f > PROB_UNLIKELY_MAG(4))
2036 iff->_prob = PROB_MIN;
2037 } else {
2038 if (f < PROB_LIKELY_MAG(4))
2039 iff->_prob = PROB_MAX;
2040 }
2041 }
2042
2043 // Clear out dead values from the debug info.
2044 kill_dead_locals();
2045
2046 // Now insert the uncommon trap subroutine call
2047 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
2048 const TypePtr* no_memory_effects = NULL;
2049 // Pass the index of the class to be loaded
2050 Node* call = make_runtime_call(RC_NO_LEAF | RC_UNCOMMON |
2051 (must_throw ? RC_MUST_THROW : 0),
2052 OptoRuntime::uncommon_trap_Type(),
2053 call_addr, "uncommon_trap", no_memory_effects,
2054 intcon(trap_request));
2055 assert(call->as_CallStaticJava()->uncommon_trap_request() == trap_request,
2056 "must extract request correctly from the graph");
2057 assert(trap_request != 0, "zero value reserved by uncommon_trap_request");
2058
2059 call->set_req(TypeFunc::ReturnAdr, returnadr());
2060 // The debug info is the only real input to this call.
2061
2062 // Halt-and-catch fire here. The above call should never return!
2063 HaltNode* halt = new HaltNode(control(), frameptr());
2064 _gvn.set_type_bottom(halt);
2065 root()->add_req(halt);
2066
2067 stop_and_kill_map();
2068 }
2069
2070
2071 //--------------------------just_allocated_object------------------------------
2072 // Report the object that was just allocated.
2073 // It must be the case that there are no intervening safepoints.
2074 // We use this to determine if an object is so "fresh" that
2075 // it does not require card marks.
2076 Node* GraphKit::just_allocated_object(Node* current_control) {
2077 if (C->recent_alloc_ctl() == current_control)
2078 return C->recent_alloc_obj();
2079 return NULL;
2080 }
2081
2082
2083 void GraphKit::round_double_arguments(ciMethod* dest_method) {
2084 // (Note: TypeFunc::make has a cache that makes this fast.)
2085 const TypeFunc* tf = TypeFunc::make(dest_method);
2086 int nargs = tf->domain()->cnt() - TypeFunc::Parms;
2087 for (int j = 0; j < nargs; j++) {
2088 const Type *targ = tf->domain()->field_at(j + TypeFunc::Parms);
2089 if( targ->basic_type() == T_DOUBLE ) {
2090 // If any parameters are doubles, they must be rounded before
2091 // the call, dstore_rounding does gvn.transform
2092 Node *arg = argument(j);
2093 arg = dstore_rounding(arg);
2094 set_argument(j, arg);
2095 }
2096 }
2097 }
2098
2099 /**
2100 * Record profiling data exact_kls for Node n with the type system so
2101 * that it can propagate it (speculation)
2102 *
2103 * @param n node that the type applies to
2104 * @param exact_kls type from profiling
2105 * @param maybe_null did profiling see null?
2106 *
2107 * @return node with improved type
2108 */
2109 Node* GraphKit::record_profile_for_speculation(Node* n, ciKlass* exact_kls, bool maybe_null) {
2110 const Type* current_type = _gvn.type(n);
2111 assert(UseTypeSpeculation, "type speculation must be on");
2112
2113 const TypePtr* speculative = current_type->speculative();
2114
2115 // Should the klass from the profile be recorded in the speculative type?
2116 if (current_type->would_improve_type(exact_kls, jvms()->depth())) {
2117 const TypeKlassPtr* tklass = TypeKlassPtr::make(exact_kls);
2118 const TypeOopPtr* xtype = tklass->as_instance_type();
2119 assert(xtype->klass_is_exact(), "Should be exact");
2120 // Any reason to believe n is not null (from this profiling or a previous one)?
2121 const TypePtr* ptr = (maybe_null && current_type->speculative_maybe_null()) ? TypePtr::BOTTOM : TypePtr::NOTNULL;
2122 // record the new speculative type's depth
2123 speculative = xtype->cast_to_ptr_type(ptr->ptr())->is_ptr();
2124 speculative = speculative->with_inline_depth(jvms()->depth());
2125 } else if (current_type->would_improve_ptr(maybe_null)) {
2126 // Profiling report that null was never seen so we can change the
2127 // speculative type to non null ptr.
2128 assert(!maybe_null, "nothing to improve");
2129 if (speculative == NULL) {
2130 speculative = TypePtr::NOTNULL;
2131 } else {
2132 const TypePtr* ptr = TypePtr::NOTNULL;
2133 speculative = speculative->cast_to_ptr_type(ptr->ptr())->is_ptr();
2134 }
2135 }
2136
2137 if (speculative != current_type->speculative()) {
2138 // Build a type with a speculative type (what we think we know
2139 // about the type but will need a guard when we use it)
2140 const TypeOopPtr* spec_type = TypeOopPtr::make(TypePtr::BotPTR, Type::OffsetBot, TypeOopPtr::InstanceBot, speculative);
2141 // We're changing the type, we need a new CheckCast node to carry
2142 // the new type. The new type depends on the control: what
2143 // profiling tells us is only valid from here as far as we can
2144 // tell.
2145 Node* cast = new CheckCastPPNode(control(), n, current_type->remove_speculative()->join_speculative(spec_type));
2146 cast = _gvn.transform(cast);
2147 replace_in_map(n, cast);
2148 n = cast;
2149 }
2150
2151 return n;
2152 }
2153
2154 /**
2155 * Record profiling data from receiver profiling at an invoke with the
2156 * type system so that it can propagate it (speculation)
2157 *
2158 * @param n receiver node
2159 *
2160 * @return node with improved type
2161 */
2162 Node* GraphKit::record_profiled_receiver_for_speculation(Node* n) {
2163 if (!UseTypeSpeculation) {
2164 return n;
2165 }
2166 ciKlass* exact_kls = profile_has_unique_klass();
2167 bool maybe_null = true;
2168 if (java_bc() == Bytecodes::_checkcast ||
2169 java_bc() == Bytecodes::_instanceof ||
2170 java_bc() == Bytecodes::_aastore) {
2171 ciProfileData* data = method()->method_data()->bci_to_data(bci());
2172 bool maybe_null = data == NULL ? true : data->as_BitData()->null_seen();
2173 }
2174 return record_profile_for_speculation(n, exact_kls, maybe_null);
2175 return n;
2176 }
2177
2178 /**
2179 * Record profiling data from argument profiling at an invoke with the
2180 * type system so that it can propagate it (speculation)
2181 *
2182 * @param dest_method target method for the call
2183 * @param bc what invoke bytecode is this?
2184 */
2185 void GraphKit::record_profiled_arguments_for_speculation(ciMethod* dest_method, Bytecodes::Code bc) {
2186 if (!UseTypeSpeculation) {
2187 return;
2188 }
2189 const TypeFunc* tf = TypeFunc::make(dest_method);
2190 int nargs = tf->domain()->cnt() - TypeFunc::Parms;
2191 int skip = Bytecodes::has_receiver(bc) ? 1 : 0;
2192 for (int j = skip, i = 0; j < nargs && i < TypeProfileArgsLimit; j++) {
2193 const Type *targ = tf->domain()->field_at(j + TypeFunc::Parms);
2194 if (targ->basic_type() == T_OBJECT || targ->basic_type() == T_ARRAY) {
2195 bool maybe_null = true;
2196 ciKlass* better_type = NULL;
2197 if (method()->argument_profiled_type(bci(), i, better_type, maybe_null)) {
2198 record_profile_for_speculation(argument(j), better_type, maybe_null);
2199 }
2200 i++;
2201 }
2202 }
2203 }
2204
2205 /**
2206 * Record profiling data from parameter profiling at an invoke with
2207 * the type system so that it can propagate it (speculation)
2208 */
2209 void GraphKit::record_profiled_parameters_for_speculation() {
2210 if (!UseTypeSpeculation) {
2211 return;
2212 }
2213 for (int i = 0, j = 0; i < method()->arg_size() ; i++) {
2214 if (_gvn.type(local(i))->isa_oopptr()) {
2215 bool maybe_null = true;
2216 ciKlass* better_type = NULL;
2217 if (method()->parameter_profiled_type(j, better_type, maybe_null)) {
2218 record_profile_for_speculation(local(i), better_type, maybe_null);
2219 }
2220 j++;
2221 }
2222 }
2223 }
2224
2225 /**
2226 * Record profiling data from return value profiling at an invoke with
2227 * the type system so that it can propagate it (speculation)
2228 */
2229 void GraphKit::record_profiled_return_for_speculation() {
2230 if (!UseTypeSpeculation) {
2231 return;
2232 }
2233 bool maybe_null = true;
2234 ciKlass* better_type = NULL;
2235 if (method()->return_profiled_type(bci(), better_type, maybe_null)) {
2236 // If profiling reports a single type for the return value,
2237 // feed it to the type system so it can propagate it as a
2238 // speculative type
2239 record_profile_for_speculation(stack(sp()-1), better_type, maybe_null);
2240 }
2241 }
2242
2243 void GraphKit::round_double_result(ciMethod* dest_method) {
2244 // A non-strict method may return a double value which has an extended
2245 // exponent, but this must not be visible in a caller which is 'strict'
2246 // If a strict caller invokes a non-strict callee, round a double result
2247
2248 BasicType result_type = dest_method->return_type()->basic_type();
2249 assert( method() != NULL, "must have caller context");
2250 if( result_type == T_DOUBLE && method()->is_strict() && !dest_method->is_strict() ) {
2251 // Destination method's return value is on top of stack
2252 // dstore_rounding() does gvn.transform
2253 Node *result = pop_pair();
2254 result = dstore_rounding(result);
2255 push_pair(result);
2256 }
2257 }
2258
2259 // rounding for strict float precision conformance
2260 Node* GraphKit::precision_rounding(Node* n) {
2261 return UseStrictFP && _method->flags().is_strict()
2262 && UseSSE == 0 && Matcher::strict_fp_requires_explicit_rounding
2263 ? _gvn.transform( new RoundFloatNode(0, n) )
2264 : n;
2265 }
2266
2267 // rounding for strict double precision conformance
2268 Node* GraphKit::dprecision_rounding(Node *n) {
2269 return UseStrictFP && _method->flags().is_strict()
2270 && UseSSE <= 1 && Matcher::strict_fp_requires_explicit_rounding
2271 ? _gvn.transform( new RoundDoubleNode(0, n) )
2272 : n;
2273 }
2274
2275 // rounding for non-strict double stores
2276 Node* GraphKit::dstore_rounding(Node* n) {
2277 return Matcher::strict_fp_requires_explicit_rounding
2278 && UseSSE <= 1
2279 ? _gvn.transform( new RoundDoubleNode(0, n) )
2280 : n;
2281 }
2282
2283 //=============================================================================
2284 // Generate a fast path/slow path idiom. Graph looks like:
2285 // [foo] indicates that 'foo' is a parameter
2286 //
2287 // [in] NULL
2288 // \ /
2289 // CmpP
2290 // Bool ne
2291 // If
2292 // / \
2293 // True False-<2>
2294 // / |
2295 // / cast_not_null
2296 // Load | | ^
2297 // [fast_test] | |
2298 // gvn to opt_test | |
2299 // / \ | <1>
2300 // True False |
2301 // | \\ |
2302 // [slow_call] \[fast_result]
2303 // Ctl Val \ \
2304 // | \ \
2305 // Catch <1> \ \
2306 // / \ ^ \ \
2307 // Ex No_Ex | \ \
2308 // | \ \ | \ <2> \
2309 // ... \ [slow_res] | | \ [null_result]
2310 // \ \--+--+--- | |
2311 // \ | / \ | /
2312 // --------Region Phi
2313 //
2314 //=============================================================================
2315 // Code is structured as a series of driver functions all called 'do_XXX' that
2316 // call a set of helper functions. Helper functions first, then drivers.
2317
2318 //------------------------------null_check_oop---------------------------------
2319 // Null check oop. Set null-path control into Region in slot 3.
2320 // Make a cast-not-nullness use the other not-null control. Return cast.
2321 Node* GraphKit::null_check_oop(Node* value, Node* *null_control,
2322 bool never_see_null,
2323 bool safe_for_replace,
2324 bool speculative) {
2325 // Initial NULL check taken path
2326 (*null_control) = top();
2327 Node* cast = null_check_common(value, T_OBJECT, false, null_control, speculative);
2328
2329 // Generate uncommon_trap:
2330 if (never_see_null && (*null_control) != top()) {
2331 // If we see an unexpected null at a check-cast we record it and force a
2332 // recompile; the offending check-cast will be compiled to handle NULLs.
2333 // If we see more than one offending BCI, then all checkcasts in the
2334 // method will be compiled to handle NULLs.
2335 PreserveJVMState pjvms(this);
2336 set_control(*null_control);
2337 replace_in_map(value, null());
2338 Deoptimization::DeoptReason reason = Deoptimization::reason_null_check(speculative);
2339 uncommon_trap(reason,
2340 Deoptimization::Action_make_not_entrant);
2341 (*null_control) = top(); // NULL path is dead
2342 }
2343 if ((*null_control) == top() && safe_for_replace) {
2344 replace_in_map(value, cast);
2345 }
2346
2347 // Cast away null-ness on the result
2348 return cast;
2349 }
2350
2351 //------------------------------opt_iff----------------------------------------
2352 // Optimize the fast-check IfNode. Set the fast-path region slot 2.
2353 // Return slow-path control.
2354 Node* GraphKit::opt_iff(Node* region, Node* iff) {
2355 IfNode *opt_iff = _gvn.transform(iff)->as_If();
2356
2357 // Fast path taken; set region slot 2
2358 Node *fast_taken = _gvn.transform( new IfFalseNode(opt_iff) );
2359 region->init_req(2,fast_taken); // Capture fast-control
2360
2361 // Fast path not-taken, i.e. slow path
2362 Node *slow_taken = _gvn.transform( new IfTrueNode(opt_iff) );
2363 return slow_taken;
2364 }
2365
2366 //-----------------------------make_runtime_call-------------------------------
2367 Node* GraphKit::make_runtime_call(int flags,
2368 const TypeFunc* call_type, address call_addr,
2369 const char* call_name,
2370 const TypePtr* adr_type,
2371 // The following parms are all optional.
2372 // The first NULL ends the list.
2373 Node* parm0, Node* parm1,
2374 Node* parm2, Node* parm3,
2375 Node* parm4, Node* parm5,
2376 Node* parm6, Node* parm7) {
2377 // Slow-path call
2378 bool is_leaf = !(flags & RC_NO_LEAF);
2379 bool has_io = (!is_leaf && !(flags & RC_NO_IO));
2380 if (call_name == NULL) {
2381 assert(!is_leaf, "must supply name for leaf");
2382 call_name = OptoRuntime::stub_name(call_addr);
2383 }
2384 CallNode* call;
2385 if (!is_leaf) {
2386 call = new CallStaticJavaNode(call_type, call_addr, call_name,
2387 bci(), adr_type);
2388 } else if (flags & RC_NO_FP) {
2389 call = new CallLeafNoFPNode(call_type, call_addr, call_name, adr_type);
2390 } else {
2391 call = new CallLeafNode(call_type, call_addr, call_name, adr_type);
2392 }
2393
2394 // The following is similar to set_edges_for_java_call,
2395 // except that the memory effects of the call are restricted to AliasIdxRaw.
2396
2397 // Slow path call has no side-effects, uses few values
2398 bool wide_in = !(flags & RC_NARROW_MEM);
2399 bool wide_out = (C->get_alias_index(adr_type) == Compile::AliasIdxBot);
2400
2401 Node* prev_mem = NULL;
2402 if (wide_in) {
2403 prev_mem = set_predefined_input_for_runtime_call(call);
2404 } else {
2405 assert(!wide_out, "narrow in => narrow out");
2406 Node* narrow_mem = memory(adr_type);
2407 prev_mem = reset_memory();
2408 map()->set_memory(narrow_mem);
2409 set_predefined_input_for_runtime_call(call);
2410 }
2411
2412 // Hook each parm in order. Stop looking at the first NULL.
2413 if (parm0 != NULL) { call->init_req(TypeFunc::Parms+0, parm0);
2414 if (parm1 != NULL) { call->init_req(TypeFunc::Parms+1, parm1);
2415 if (parm2 != NULL) { call->init_req(TypeFunc::Parms+2, parm2);
2416 if (parm3 != NULL) { call->init_req(TypeFunc::Parms+3, parm3);
2417 if (parm4 != NULL) { call->init_req(TypeFunc::Parms+4, parm4);
2418 if (parm5 != NULL) { call->init_req(TypeFunc::Parms+5, parm5);
2419 if (parm6 != NULL) { call->init_req(TypeFunc::Parms+6, parm6);
2420 if (parm7 != NULL) { call->init_req(TypeFunc::Parms+7, parm7);
2421 /* close each nested if ===> */ } } } } } } } }
2422 assert(call->in(call->req()-1) != NULL, "must initialize all parms");
2423
2424 if (!is_leaf) {
2425 // Non-leaves can block and take safepoints:
2426 add_safepoint_edges(call, ((flags & RC_MUST_THROW) != 0));
2427 }
2428 // Non-leaves can throw exceptions:
2429 if (has_io) {
2430 call->set_req(TypeFunc::I_O, i_o());
2431 }
2432
2433 if (flags & RC_UNCOMMON) {
2434 // Set the count to a tiny probability. Cf. Estimate_Block_Frequency.
2435 // (An "if" probability corresponds roughly to an unconditional count.
2436 // Sort of.)
2437 call->set_cnt(PROB_UNLIKELY_MAG(4));
2438 }
2439
2440 Node* c = _gvn.transform(call);
2441 assert(c == call, "cannot disappear");
2442
2443 if (wide_out) {
2444 // Slow path call has full side-effects.
2445 set_predefined_output_for_runtime_call(call);
2446 } else {
2447 // Slow path call has few side-effects, and/or sets few values.
2448 set_predefined_output_for_runtime_call(call, prev_mem, adr_type);
2449 }
2450
2451 if (has_io) {
2452 set_i_o(_gvn.transform(new ProjNode(call, TypeFunc::I_O)));
2453 }
2454 return call;
2455
2456 }
2457
2458 //------------------------------merge_memory-----------------------------------
2459 // Merge memory from one path into the current memory state.
2460 void GraphKit::merge_memory(Node* new_mem, Node* region, int new_path) {
2461 for (MergeMemStream mms(merged_memory(), new_mem->as_MergeMem()); mms.next_non_empty2(); ) {
2462 Node* old_slice = mms.force_memory();
2463 Node* new_slice = mms.memory2();
2464 if (old_slice != new_slice) {
2465 PhiNode* phi;
2466 if (old_slice->is_Phi() && old_slice->as_Phi()->region() == region) {
2467 if (mms.is_empty()) {
2468 // clone base memory Phi's inputs for this memory slice
2469 assert(old_slice == mms.base_memory(), "sanity");
2470 phi = PhiNode::make(region, NULL, Type::MEMORY, mms.adr_type(C));
2471 _gvn.set_type(phi, Type::MEMORY);
2472 for (uint i = 1; i < phi->req(); i++) {
2473 phi->init_req(i, old_slice->in(i));
2474 }
2475 } else {
2476 phi = old_slice->as_Phi(); // Phi was generated already
2477 }
2478 } else {
2479 phi = PhiNode::make(region, old_slice, Type::MEMORY, mms.adr_type(C));
2480 _gvn.set_type(phi, Type::MEMORY);
2481 }
2482 phi->set_req(new_path, new_slice);
2483 mms.set_memory(phi);
2484 }
2485 }
2486 }
2487
2488 //------------------------------make_slow_call_ex------------------------------
2489 // Make the exception handler hookups for the slow call
2490 void GraphKit::make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj, bool deoptimize) {
2491 if (stopped()) return;
2492
2493 // Make a catch node with just two handlers: fall-through and catch-all
2494 Node* i_o = _gvn.transform( new ProjNode(call, TypeFunc::I_O, separate_io_proj) );
2495 Node* catc = _gvn.transform( new CatchNode(control(), i_o, 2) );
2496 Node* norm = _gvn.transform( new CatchProjNode(catc, CatchProjNode::fall_through_index, CatchProjNode::no_handler_bci) );
2497 Node* excp = _gvn.transform( new CatchProjNode(catc, CatchProjNode::catch_all_index, CatchProjNode::no_handler_bci) );
2498
2499 { PreserveJVMState pjvms(this);
2500 set_control(excp);
2501 set_i_o(i_o);
2502
2503 if (excp != top()) {
2504 if (deoptimize) {
2505 // Deoptimize if an exception is caught. Don't construct exception state in this case.
2506 uncommon_trap(Deoptimization::Reason_unhandled,
2507 Deoptimization::Action_none);
2508 } else {
2509 // Create an exception state also.
2510 // Use an exact type if the caller has specified a specific exception.
2511 const Type* ex_type = TypeOopPtr::make_from_klass_unique(ex_klass)->cast_to_ptr_type(TypePtr::NotNull);
2512 Node* ex_oop = new CreateExNode(ex_type, control(), i_o);
2513 add_exception_state(make_exception_state(_gvn.transform(ex_oop)));
2514 }
2515 }
2516 }
2517
2518 // Get the no-exception control from the CatchNode.
2519 set_control(norm);
2520 }
2521
2522 static IfNode* gen_subtype_check_compare(Node* ctrl, Node* in1, Node* in2, BoolTest::mask test, float p, PhaseGVN* gvn, BasicType bt) {
2523 Node* cmp = NULL;
2524 switch(bt) {
2525 case T_INT: cmp = new CmpINode(in1, in2); break;
2526 case T_ADDRESS: cmp = new CmpPNode(in1, in2); break;
2527 default: fatal(err_msg("unexpected comparison type %s", type2name(bt)));
2528 }
2529 gvn->transform(cmp);
2530 Node* bol = gvn->transform(new BoolNode(cmp, test));
2531 IfNode* iff = new IfNode(ctrl, bol, p, COUNT_UNKNOWN);
2532 gvn->transform(iff);
2533 if (!bol->is_Con()) gvn->record_for_igvn(iff);
2534 return iff;
2535 }
2536
2537
2538 //-------------------------------gen_subtype_check-----------------------------
2539 // Generate a subtyping check. Takes as input the subtype and supertype.
2540 // Returns 2 values: sets the default control() to the true path and returns
2541 // the false path. Only reads invariant memory; sets no (visible) memory.
2542 // The PartialSubtypeCheckNode sets the hidden 1-word cache in the encoding
2543 // but that's not exposed to the optimizer. This call also doesn't take in an
2544 // Object; if you wish to check an Object you need to load the Object's class
2545 // prior to coming here.
2546 Node* Phase::gen_subtype_check(Node* subklass, Node* superklass, Node** ctrl, MergeMemNode* mem, PhaseGVN* gvn) {
2547 Compile* C = gvn->C;
2548
2549 if ((*ctrl)->is_top()) {
2550 return C->top();
2551 }
2552
2553 // Fast check for identical types, perhaps identical constants.
2554 // The types can even be identical non-constants, in cases
2555 // involving Array.newInstance, Object.clone, etc.
2556 if (subklass == superklass)
2557 return C->top(); // false path is dead; no test needed.
2558
2559 if (gvn->type(superklass)->singleton()) {
2560 ciKlass* superk = gvn->type(superklass)->is_klassptr()->klass();
2561 ciKlass* subk = gvn->type(subklass)->is_klassptr()->klass();
2562
2563 // In the common case of an exact superklass, try to fold up the
2564 // test before generating code. You may ask, why not just generate
2565 // the code and then let it fold up? The answer is that the generated
2566 // code will necessarily include null checks, which do not always
2567 // completely fold away. If they are also needless, then they turn
2568 // into a performance loss. Example:
2569 // Foo[] fa = blah(); Foo x = fa[0]; fa[1] = x;
2570 // Here, the type of 'fa' is often exact, so the store check
2571 // of fa[1]=x will fold up, without testing the nullness of x.
2572 switch (C->static_subtype_check(superk, subk)) {
2573 case Compile::SSC_always_false:
2574 {
2575 Node* always_fail = *ctrl;
2576 *ctrl = gvn->C->top();
2577 return always_fail;
2578 }
2579 case Compile::SSC_always_true:
2580 return C->top();
2581 case Compile::SSC_easy_test:
2582 {
2583 // Just do a direct pointer compare and be done.
2584 IfNode* iff = gen_subtype_check_compare(*ctrl, subklass, superklass, BoolTest::eq, PROB_STATIC_FREQUENT, gvn, T_ADDRESS);
2585 *ctrl = gvn->transform(new IfTrueNode(iff));
2586 return gvn->transform(new IfFalseNode(iff));
2587 }
2588 case Compile::SSC_full_test:
2589 break;
2590 default:
2591 ShouldNotReachHere();
2592 }
2593 }
2594
2595 // %%% Possible further optimization: Even if the superklass is not exact,
2596 // if the subklass is the unique subtype of the superklass, the check
2597 // will always succeed. We could leave a dependency behind to ensure this.
2598
2599 // First load the super-klass's check-offset
2600 Node *p1 = gvn->transform(new AddPNode(superklass, superklass, gvn->MakeConX(in_bytes(Klass::super_check_offset_offset()))));
2601 Node* m = mem->memory_at(C->get_alias_index(gvn->type(p1)->is_ptr()));
2602 Node *chk_off = gvn->transform(new LoadINode(NULL, m, p1, gvn->type(p1)->is_ptr(), TypeInt::INT, MemNode::unordered));
2603 int cacheoff_con = in_bytes(Klass::secondary_super_cache_offset());
2604 bool might_be_cache = (gvn->find_int_con(chk_off, cacheoff_con) == cacheoff_con);
2605
2606 // Load from the sub-klass's super-class display list, or a 1-word cache of
2607 // the secondary superclass list, or a failing value with a sentinel offset
2608 // if the super-klass is an interface or exceptionally deep in the Java
2609 // hierarchy and we have to scan the secondary superclass list the hard way.
2610 // Worst-case type is a little odd: NULL is allowed as a result (usually
2611 // klass loads can never produce a NULL).
2612 Node *chk_off_X = chk_off;
2613 #ifdef _LP64
2614 chk_off_X = gvn->transform(new ConvI2LNode(chk_off_X));
2615 #endif
2616 Node *p2 = gvn->transform(new AddPNode(subklass,subklass,chk_off_X));
2617 // For some types like interfaces the following loadKlass is from a 1-word
2618 // cache which is mutable so can't use immutable memory. Other
2619 // types load from the super-class display table which is immutable.
2620 m = mem->memory_at(C->get_alias_index(gvn->type(p2)->is_ptr()));
2621 Node *kmem = might_be_cache ? m : C->immutable_memory();
2622 Node *nkls = gvn->transform(LoadKlassNode::make(*gvn, NULL, kmem, p2, gvn->type(p2)->is_ptr(), TypeKlassPtr::OBJECT_OR_NULL));
2623
2624 // Compile speed common case: ARE a subtype and we canNOT fail
2625 if( superklass == nkls )
2626 return C->top(); // false path is dead; no test needed.
2627
2628 // See if we get an immediate positive hit. Happens roughly 83% of the
2629 // time. Test to see if the value loaded just previously from the subklass
2630 // is exactly the superklass.
2631 IfNode *iff1 = gen_subtype_check_compare(*ctrl, superklass, nkls, BoolTest::eq, PROB_LIKELY(0.83f), gvn, T_ADDRESS);
2632 Node *iftrue1 = gvn->transform( new IfTrueNode (iff1));
2633 *ctrl = gvn->transform(new IfFalseNode(iff1));
2634
2635 // Compile speed common case: Check for being deterministic right now. If
2636 // chk_off is a constant and not equal to cacheoff then we are NOT a
2637 // subklass. In this case we need exactly the 1 test above and we can
2638 // return those results immediately.
2639 if (!might_be_cache) {
2640 Node* not_subtype_ctrl = *ctrl;
2641 *ctrl = iftrue1; // We need exactly the 1 test above
2642 return not_subtype_ctrl;
2643 }
2644
2645 // Gather the various success & failures here
2646 RegionNode *r_ok_subtype = new RegionNode(4);
2647 gvn->record_for_igvn(r_ok_subtype);
2648 RegionNode *r_not_subtype = new RegionNode(3);
2649 gvn->record_for_igvn(r_not_subtype);
2650
2651 r_ok_subtype->init_req(1, iftrue1);
2652
2653 // Check for immediate negative hit. Happens roughly 11% of the time (which
2654 // is roughly 63% of the remaining cases). Test to see if the loaded
2655 // check-offset points into the subklass display list or the 1-element
2656 // cache. If it points to the display (and NOT the cache) and the display
2657 // missed then it's not a subtype.
2658 Node *cacheoff = gvn->intcon(cacheoff_con);
2659 IfNode *iff2 = gen_subtype_check_compare(*ctrl, chk_off, cacheoff, BoolTest::ne, PROB_LIKELY(0.63f), gvn, T_INT);
2660 r_not_subtype->init_req(1, gvn->transform(new IfTrueNode (iff2)));
2661 *ctrl = gvn->transform(new IfFalseNode(iff2));
2662
2663 // Check for self. Very rare to get here, but it is taken 1/3 the time.
2664 // No performance impact (too rare) but allows sharing of secondary arrays
2665 // which has some footprint reduction.
2666 IfNode *iff3 = gen_subtype_check_compare(*ctrl, subklass, superklass, BoolTest::eq, PROB_LIKELY(0.36f), gvn, T_ADDRESS);
2667 r_ok_subtype->init_req(2, gvn->transform(new IfTrueNode(iff3)));
2668 *ctrl = gvn->transform(new IfFalseNode(iff3));
2669
2670 // -- Roads not taken here: --
2671 // We could also have chosen to perform the self-check at the beginning
2672 // of this code sequence, as the assembler does. This would not pay off
2673 // the same way, since the optimizer, unlike the assembler, can perform
2674 // static type analysis to fold away many successful self-checks.
2675 // Non-foldable self checks work better here in second position, because
2676 // the initial primary superclass check subsumes a self-check for most
2677 // types. An exception would be a secondary type like array-of-interface,
2678 // which does not appear in its own primary supertype display.
2679 // Finally, we could have chosen to move the self-check into the
2680 // PartialSubtypeCheckNode, and from there out-of-line in a platform
2681 // dependent manner. But it is worthwhile to have the check here,
2682 // where it can be perhaps be optimized. The cost in code space is
2683 // small (register compare, branch).
2684
2685 // Now do a linear scan of the secondary super-klass array. Again, no real
2686 // performance impact (too rare) but it's gotta be done.
2687 // Since the code is rarely used, there is no penalty for moving it
2688 // out of line, and it can only improve I-cache density.
2689 // The decision to inline or out-of-line this final check is platform
2690 // dependent, and is found in the AD file definition of PartialSubtypeCheck.
2691 Node* psc = gvn->transform(
2692 new PartialSubtypeCheckNode(*ctrl, subklass, superklass));
2693
2694 IfNode *iff4 = gen_subtype_check_compare(*ctrl, psc, gvn->zerocon(T_OBJECT), BoolTest::ne, PROB_FAIR, gvn, T_ADDRESS);
2695 r_not_subtype->init_req(2, gvn->transform(new IfTrueNode (iff4)));
2696 r_ok_subtype ->init_req(3, gvn->transform(new IfFalseNode(iff4)));
2697
2698 // Return false path; set default control to true path.
2699 *ctrl = gvn->transform(r_ok_subtype);
2700 return gvn->transform(r_not_subtype);
2701 }
2702
2703 // Profile-driven exact type check:
2704 Node* GraphKit::type_check_receiver(Node* receiver, ciKlass* klass,
2705 float prob,
2706 Node* *casted_receiver) {
2707 const TypeKlassPtr* tklass = TypeKlassPtr::make(klass);
2708 Node* recv_klass = load_object_klass(receiver);
2709 Node* want_klass = makecon(tklass);
2710 Node* cmp = _gvn.transform( new CmpPNode(recv_klass, want_klass) );
2711 Node* bol = _gvn.transform( new BoolNode(cmp, BoolTest::eq) );
2712 IfNode* iff = create_and_xform_if(control(), bol, prob, COUNT_UNKNOWN);
2713 set_control( _gvn.transform( new IfTrueNode (iff) ));
2714 Node* fail = _gvn.transform( new IfFalseNode(iff) );
2715
2716 const TypeOopPtr* recv_xtype = tklass->as_instance_type();
2717 assert(recv_xtype->klass_is_exact(), "");
2718
2719 // Subsume downstream occurrences of receiver with a cast to
2720 // recv_xtype, since now we know what the type will be.
2721 Node* cast = new CheckCastPPNode(control(), receiver, recv_xtype);
2722 (*casted_receiver) = _gvn.transform(cast);
2723 // (User must make the replace_in_map call.)
2724
2725 return fail;
2726 }
2727
2728
2729 //------------------------------seems_never_null-------------------------------
2730 // Use null_seen information if it is available from the profile.
2731 // If we see an unexpected null at a type check we record it and force a
2732 // recompile; the offending check will be recompiled to handle NULLs.
2733 // If we see several offending BCIs, then all checks in the
2734 // method will be recompiled.
2735 bool GraphKit::seems_never_null(Node* obj, ciProfileData* data, bool& speculating) {
2736 speculating = !_gvn.type(obj)->speculative_maybe_null();
2737 Deoptimization::DeoptReason reason = Deoptimization::reason_null_check(speculating);
2738 if (UncommonNullCast // Cutout for this technique
2739 && obj != null() // And not the -Xcomp stupid case?
2740 && !too_many_traps(reason)
2741 ) {
2742 if (speculating) {
2743 return true;
2744 }
2745 if (data == NULL)
2746 // Edge case: no mature data. Be optimistic here.
2747 return true;
2748 // If the profile has not seen a null, assume it won't happen.
2749 assert(java_bc() == Bytecodes::_checkcast ||
2750 java_bc() == Bytecodes::_instanceof ||
2751 java_bc() == Bytecodes::_aastore, "MDO must collect null_seen bit here");
2752 return !data->as_BitData()->null_seen();
2753 }
2754 speculating = false;
2755 return false;
2756 }
2757
2758 //------------------------maybe_cast_profiled_receiver-------------------------
2759 // If the profile has seen exactly one type, narrow to exactly that type.
2760 // Subsequent type checks will always fold up.
2761 Node* GraphKit::maybe_cast_profiled_receiver(Node* not_null_obj,
2762 ciKlass* require_klass,
2763 ciKlass* spec_klass,
2764 bool safe_for_replace) {
2765 if (!UseTypeProfile || !TypeProfileCasts) return NULL;
2766
2767 Deoptimization::DeoptReason reason = Deoptimization::reason_class_check(spec_klass != NULL);
2768
2769 // Make sure we haven't already deoptimized from this tactic.
2770 if (too_many_traps(reason) || too_many_recompiles(reason))
2771 return NULL;
2772
2773 // (No, this isn't a call, but it's enough like a virtual call
2774 // to use the same ciMethod accessor to get the profile info...)
2775 // If we have a speculative type use it instead of profiling (which
2776 // may not help us)
2777 ciKlass* exact_kls = spec_klass == NULL ? profile_has_unique_klass() : spec_klass;
2778 if (exact_kls != NULL) {// no cast failures here
2779 if (require_klass == NULL ||
2780 C->static_subtype_check(require_klass, exact_kls) == Compile::SSC_always_true) {
2781 // If we narrow the type to match what the type profile sees or
2782 // the speculative type, we can then remove the rest of the
2783 // cast.
2784 // This is a win, even if the exact_kls is very specific,
2785 // because downstream operations, such as method calls,
2786 // will often benefit from the sharper type.
2787 Node* exact_obj = not_null_obj; // will get updated in place...
2788 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0,
2789 &exact_obj);
2790 { PreserveJVMState pjvms(this);
2791 set_control(slow_ctl);
2792 uncommon_trap_exact(reason, Deoptimization::Action_maybe_recompile);
2793 }
2794 if (safe_for_replace) {
2795 replace_in_map(not_null_obj, exact_obj);
2796 }
2797 return exact_obj;
2798 }
2799 // assert(ssc == Compile::SSC_always_true)... except maybe the profile lied to us.
2800 }
2801
2802 return NULL;
2803 }
2804
2805 /**
2806 * Cast obj to type and emit guard unless we had too many traps here
2807 * already
2808 *
2809 * @param obj node being casted
2810 * @param type type to cast the node to
2811 * @param not_null true if we know node cannot be null
2812 */
2813 Node* GraphKit::maybe_cast_profiled_obj(Node* obj,
2814 ciKlass* type,
2815 bool not_null) {
2816 if (stopped()) {
2817 return obj;
2818 }
2819
2820 // type == NULL if profiling tells us this object is always null
2821 if (type != NULL) {
2822 Deoptimization::DeoptReason class_reason = Deoptimization::Reason_speculate_class_check;
2823 Deoptimization::DeoptReason null_reason = Deoptimization::Reason_speculate_null_check;
2824
2825 if (!too_many_traps(null_reason) && !too_many_recompiles(null_reason) &&
2826 !too_many_traps(class_reason) &&
2827 !too_many_recompiles(class_reason)) {
2828 Node* not_null_obj = NULL;
2829 // not_null is true if we know the object is not null and
2830 // there's no need for a null check
2831 if (!not_null) {
2832 Node* null_ctl = top();
2833 not_null_obj = null_check_oop(obj, &null_ctl, true, true, true);
2834 assert(null_ctl->is_top(), "no null control here");
2835 } else {
2836 not_null_obj = obj;
2837 }
2838
2839 Node* exact_obj = not_null_obj;
2840 ciKlass* exact_kls = type;
2841 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0,
2842 &exact_obj);
2843 {
2844 PreserveJVMState pjvms(this);
2845 set_control(slow_ctl);
2846 uncommon_trap_exact(class_reason, Deoptimization::Action_maybe_recompile);
2847 }
2848 replace_in_map(not_null_obj, exact_obj);
2849 obj = exact_obj;
2850 }
2851 } else {
2852 if (!too_many_traps(Deoptimization::Reason_null_assert) &&
2853 !too_many_recompiles(Deoptimization::Reason_null_assert)) {
2854 Node* exact_obj = null_assert(obj);
2855 replace_in_map(obj, exact_obj);
2856 obj = exact_obj;
2857 }
2858 }
2859 return obj;
2860 }
2861
2862 //-------------------------------gen_instanceof--------------------------------
2863 // Generate an instance-of idiom. Used by both the instance-of bytecode
2864 // and the reflective instance-of call.
2865 Node* GraphKit::gen_instanceof(Node* obj, Node* superklass, bool safe_for_replace) {
2866 kill_dead_locals(); // Benefit all the uncommon traps
2867 assert( !stopped(), "dead parse path should be checked in callers" );
2868 assert(!TypePtr::NULL_PTR->higher_equal(_gvn.type(superklass)->is_klassptr()),
2869 "must check for not-null not-dead klass in callers");
2870
2871 // Make the merge point
2872 enum { _obj_path = 1, _fail_path, _null_path, PATH_LIMIT };
2873 RegionNode* region = new RegionNode(PATH_LIMIT);
2874 Node* phi = new PhiNode(region, TypeInt::BOOL);
2875 C->set_has_split_ifs(true); // Has chance for split-if optimization
2876
2877 ciProfileData* data = NULL;
2878 if (java_bc() == Bytecodes::_instanceof) { // Only for the bytecode
2879 data = method()->method_data()->bci_to_data(bci());
2880 }
2881 bool speculative_not_null = false;
2882 bool never_see_null = (ProfileDynamicTypes // aggressive use of profile
2883 && seems_never_null(obj, data, speculative_not_null));
2884
2885 // Null check; get casted pointer; set region slot 3
2886 Node* null_ctl = top();
2887 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null, safe_for_replace, speculative_not_null);
2888
2889 // If not_null_obj is dead, only null-path is taken
2890 if (stopped()) { // Doing instance-of on a NULL?
2891 set_control(null_ctl);
2892 return intcon(0);
2893 }
2894 region->init_req(_null_path, null_ctl);
2895 phi ->init_req(_null_path, intcon(0)); // Set null path value
2896 if (null_ctl == top()) {
2897 // Do this eagerly, so that pattern matches like is_diamond_phi
2898 // will work even during parsing.
2899 assert(_null_path == PATH_LIMIT-1, "delete last");
2900 region->del_req(_null_path);
2901 phi ->del_req(_null_path);
2902 }
2903
2904 // Do we know the type check always succeed?
2905 bool known_statically = false;
2906 if (_gvn.type(superklass)->singleton()) {
2907 ciKlass* superk = _gvn.type(superklass)->is_klassptr()->klass();
2908 ciKlass* subk = _gvn.type(obj)->is_oopptr()->klass();
2909 if (subk != NULL && subk->is_loaded()) {
2910 int static_res = C->static_subtype_check(superk, subk);
2911 known_statically = (static_res == Compile::SSC_always_true || static_res == Compile::SSC_always_false);
2912 }
2913 }
2914
2915 if (known_statically && UseTypeSpeculation) {
2916 // If we know the type check always succeeds then we don't use the
2917 // profiling data at this bytecode. Don't lose it, feed it to the
2918 // type system as a speculative type.
2919 not_null_obj = record_profiled_receiver_for_speculation(not_null_obj);
2920 } else {
2921 const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
2922 // We may not have profiling here or it may not help us. If we
2923 // have a speculative type use it to perform an exact cast.
2924 ciKlass* spec_obj_type = obj_type->speculative_type();
2925 if (spec_obj_type != NULL || (ProfileDynamicTypes && data != NULL)) {
2926 Node* cast_obj = maybe_cast_profiled_receiver(not_null_obj, NULL, spec_obj_type, safe_for_replace);
2927 if (stopped()) { // Profile disagrees with this path.
2928 set_control(null_ctl); // Null is the only remaining possibility.
2929 return intcon(0);
2930 }
2931 if (cast_obj != NULL) {
2932 not_null_obj = cast_obj;
2933 }
2934 }
2935 }
2936
2937 if (ShenandoahVerifyReadsToFromSpace) {
2938 not_null_obj = shenandoah_read_barrier(not_null_obj);
2939 }
2940
2941 // Load the object's klass
2942 Node* obj_klass = load_object_klass(not_null_obj);
2943
2944 // Generate the subtype check
2945 Node* not_subtype_ctrl = gen_subtype_check(obj_klass, superklass);
2946
2947 // Plug in the success path to the general merge in slot 1.
2948 region->init_req(_obj_path, control());
2949 phi ->init_req(_obj_path, intcon(1));
2950
2951 // Plug in the failing path to the general merge in slot 2.
2952 region->init_req(_fail_path, not_subtype_ctrl);
2953 phi ->init_req(_fail_path, intcon(0));
2954
2955 // Return final merged results
2956 set_control( _gvn.transform(region) );
2957 record_for_igvn(region);
2958 return _gvn.transform(phi);
2959 }
2960
2961 //-------------------------------gen_checkcast---------------------------------
2962 // Generate a checkcast idiom. Used by both the checkcast bytecode and the
2963 // array store bytecode. Stack must be as-if BEFORE doing the bytecode so the
2964 // uncommon-trap paths work. Adjust stack after this call.
2965 // If failure_control is supplied and not null, it is filled in with
2966 // the control edge for the cast failure. Otherwise, an appropriate
2967 // uncommon trap or exception is thrown.
2968 Node* GraphKit::gen_checkcast(Node *obj, Node* superklass,
2969 Node* *failure_control) {
2970 kill_dead_locals(); // Benefit all the uncommon traps
2971 const TypeKlassPtr *tk = _gvn.type(superklass)->is_klassptr();
2972 const Type *toop = TypeOopPtr::make_from_klass(tk->klass());
2973
2974 // Fast cutout: Check the case that the cast is vacuously true.
2975 // This detects the common cases where the test will short-circuit
2976 // away completely. We do this before we perform the null check,
2977 // because if the test is going to turn into zero code, we don't
2978 // want a residual null check left around. (Causes a slowdown,
2979 // for example, in some objArray manipulations, such as a[i]=a[j].)
2980 if (tk->singleton()) {
2981 const TypeOopPtr* objtp = _gvn.type(obj)->isa_oopptr();
2982 if (objtp != NULL && objtp->klass() != NULL) {
2983 switch (C->static_subtype_check(tk->klass(), objtp->klass())) {
2984 case Compile::SSC_always_true:
2985 // If we know the type check always succeed then we don't use
2986 // the profiling data at this bytecode. Don't lose it, feed it
2987 // to the type system as a speculative type.
2988 return record_profiled_receiver_for_speculation(obj);
2989 case Compile::SSC_always_false:
2990 // It needs a null check because a null will *pass* the cast check.
2991 // A non-null value will always produce an exception.
2992 return null_assert(obj);
2993 }
2994 }
2995 }
2996
2997 ciProfileData* data = NULL;
2998 bool safe_for_replace = false;
2999 if (failure_control == NULL) { // use MDO in regular case only
3000 assert(java_bc() == Bytecodes::_aastore ||
3001 java_bc() == Bytecodes::_checkcast,
3002 "interpreter profiles type checks only for these BCs");
3003 data = method()->method_data()->bci_to_data(bci());
3004 safe_for_replace = true;
3005 }
3006
3007 // Make the merge point
3008 enum { _obj_path = 1, _null_path, PATH_LIMIT };
3009 RegionNode* region = new RegionNode(PATH_LIMIT);
3010 Node* phi = new PhiNode(region, toop);
3011 C->set_has_split_ifs(true); // Has chance for split-if optimization
3012
3013 // Use null-cast information if it is available
3014 bool speculative_not_null = false;
3015 bool never_see_null = ((failure_control == NULL) // regular case only
3016 && seems_never_null(obj, data, speculative_not_null));
3017
3018 // Null check; get casted pointer; set region slot 3
3019 Node* null_ctl = top();
3020 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null, safe_for_replace, speculative_not_null);
3021
3022 if (ShenandoahVerifyReadsToFromSpace) {
3023 not_null_obj = shenandoah_read_barrier(not_null_obj);
3024 }
3025
3026 // If not_null_obj is dead, only null-path is taken
3027 if (stopped()) { // Doing instance-of on a NULL?
3028 set_control(null_ctl);
3029 return null();
3030 }
3031 region->init_req(_null_path, null_ctl);
3032 phi ->init_req(_null_path, null()); // Set null path value
3033 if (null_ctl == top()) {
3034 // Do this eagerly, so that pattern matches like is_diamond_phi
3035 // will work even during parsing.
3036 assert(_null_path == PATH_LIMIT-1, "delete last");
3037 region->del_req(_null_path);
3038 phi ->del_req(_null_path);
3039 }
3040
3041 Node* cast_obj = NULL;
3042 if (tk->klass_is_exact()) {
3043 // The following optimization tries to statically cast the speculative type of the object
3044 // (for example obtained during profiling) to the type of the superklass and then do a
3045 // dynamic check that the type of the object is what we expect. To work correctly
3046 // for checkcast and aastore the type of superklass should be exact.
3047 const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
3048 // We may not have profiling here or it may not help us. If we have
3049 // a speculative type use it to perform an exact cast.
3050 ciKlass* spec_obj_type = obj_type->speculative_type();
3051 if (spec_obj_type != NULL || data != NULL) {
3052 cast_obj = maybe_cast_profiled_receiver(not_null_obj, tk->klass(), spec_obj_type, safe_for_replace);
3053 if (cast_obj != NULL) {
3054 if (failure_control != NULL) // failure is now impossible
3055 (*failure_control) = top();
3056 // adjust the type of the phi to the exact klass:
3057 phi->raise_bottom_type(_gvn.type(cast_obj)->meet_speculative(TypePtr::NULL_PTR));
3058 }
3059 }
3060 }
3061
3062 if (cast_obj == NULL) {
3063 // Load the object's klass
3064 Node* obj_klass = load_object_klass(not_null_obj);
3065
3066 // Generate the subtype check
3067 Node* not_subtype_ctrl = gen_subtype_check( obj_klass, superklass );
3068
3069 // Plug in success path into the merge
3070 cast_obj = _gvn.transform(new CheckCastPPNode(control(), not_null_obj, toop));
3071 // Failure path ends in uncommon trap (or may be dead - failure impossible)
3072 if (failure_control == NULL) {
3073 if (not_subtype_ctrl != top()) { // If failure is possible
3074 PreserveJVMState pjvms(this);
3075 set_control(not_subtype_ctrl);
3076 builtin_throw(Deoptimization::Reason_class_check, obj_klass);
3077 }
3078 } else {
3079 (*failure_control) = not_subtype_ctrl;
3080 }
3081 }
3082
3083 region->init_req(_obj_path, control());
3084 phi ->init_req(_obj_path, cast_obj);
3085
3086 // A merge of NULL or Casted-NotNull obj
3087 Node* res = _gvn.transform(phi);
3088
3089 // Note I do NOT always 'replace_in_map(obj,result)' here.
3090 // if( tk->klass()->can_be_primary_super() )
3091 // This means that if I successfully store an Object into an array-of-String
3092 // I 'forget' that the Object is really now known to be a String. I have to
3093 // do this because we don't have true union types for interfaces - if I store
3094 // a Baz into an array-of-Interface and then tell the optimizer it's an
3095 // Interface, I forget that it's also a Baz and cannot do Baz-like field
3096 // references to it. FIX THIS WHEN UNION TYPES APPEAR!
3097 // replace_in_map( obj, res );
3098
3099 // Return final merged results
3100 set_control( _gvn.transform(region) );
3101 record_for_igvn(region);
3102 return res;
3103 }
3104
3105 //------------------------------next_monitor-----------------------------------
3106 // What number should be given to the next monitor?
3107 int GraphKit::next_monitor() {
3108 int current = jvms()->monitor_depth()* C->sync_stack_slots();
3109 int next = current + C->sync_stack_slots();
3110 // Keep the toplevel high water mark current:
3111 if (C->fixed_slots() < next) C->set_fixed_slots(next);
3112 return current;
3113 }
3114
3115 //------------------------------insert_mem_bar---------------------------------
3116 // Memory barrier to avoid floating things around
3117 // The membar serves as a pinch point between both control and all memory slices.
3118 Node* GraphKit::insert_mem_bar(int opcode, Node* precedent) {
3119 MemBarNode* mb = MemBarNode::make(C, opcode, Compile::AliasIdxBot, precedent);
3120 mb->init_req(TypeFunc::Control, control());
3121 mb->init_req(TypeFunc::Memory, reset_memory());
3122 Node* membar = _gvn.transform(mb);
3123 set_control(_gvn.transform(new ProjNode(membar, TypeFunc::Control)));
3124 set_all_memory_call(membar);
3125 return membar;
3126 }
3127
3128 //-------------------------insert_mem_bar_volatile----------------------------
3129 // Memory barrier to avoid floating things around
3130 // The membar serves as a pinch point between both control and memory(alias_idx).
3131 // If you want to make a pinch point on all memory slices, do not use this
3132 // function (even with AliasIdxBot); use insert_mem_bar() instead.
3133 Node* GraphKit::insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent) {
3134 // When Parse::do_put_xxx updates a volatile field, it appends a series
3135 // of MemBarVolatile nodes, one for *each* volatile field alias category.
3136 // The first membar is on the same memory slice as the field store opcode.
3137 // This forces the membar to follow the store. (Bug 6500685 broke this.)
3138 // All the other membars (for other volatile slices, including AliasIdxBot,
3139 // which stands for all unknown volatile slices) are control-dependent
3140 // on the first membar. This prevents later volatile loads or stores
3141 // from sliding up past the just-emitted store.
3142
3143 MemBarNode* mb = MemBarNode::make(C, opcode, alias_idx, precedent);
3144 mb->set_req(TypeFunc::Control,control());
3145 if (alias_idx == Compile::AliasIdxBot) {
3146 mb->set_req(TypeFunc::Memory, merged_memory()->base_memory());
3147 } else {
3148 assert(!(opcode == Op_Initialize && alias_idx != Compile::AliasIdxRaw), "fix caller");
3149 mb->set_req(TypeFunc::Memory, memory(alias_idx));
3150 }
3151 Node* membar = _gvn.transform(mb);
3152 set_control(_gvn.transform(new ProjNode(membar, TypeFunc::Control)));
3153 if (alias_idx == Compile::AliasIdxBot) {
3154 merged_memory()->set_base_memory(_gvn.transform(new ProjNode(membar, TypeFunc::Memory)));
3155 } else {
3156 set_memory(_gvn.transform(new ProjNode(membar, TypeFunc::Memory)),alias_idx);
3157 }
3158 return membar;
3159 }
3160
3161 //------------------------------shared_lock------------------------------------
3162 // Emit locking code.
3163 FastLockNode* GraphKit::shared_lock(Node* obj) {
3164 // bci is either a monitorenter bc or InvocationEntryBci
3165 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
3166 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
3167
3168 if( !GenerateSynchronizationCode )
3169 return NULL; // Not locking things?
3170 if (stopped()) // Dead monitor?
3171 return NULL;
3172
3173 assert(dead_locals_are_killed(), "should kill locals before sync. point");
3174
3175 obj = shenandoah_write_barrier(obj);
3176
3177 // Box the stack location
3178 Node* box = _gvn.transform(new BoxLockNode(next_monitor()));
3179 Node* mem = reset_memory();
3180
3181 FastLockNode * flock = _gvn.transform(new FastLockNode(0, obj, box) )->as_FastLock();
3182 if (UseBiasedLocking && PrintPreciseBiasedLockingStatistics) {
3183 // Create the counters for this fast lock.
3184 flock->create_lock_counter(sync_jvms()); // sync_jvms used to get current bci
3185 }
3186
3187 // Create the rtm counters for this fast lock if needed.
3188 flock->create_rtm_lock_counter(sync_jvms()); // sync_jvms used to get current bci
3189
3190 // Add monitor to debug info for the slow path. If we block inside the
3191 // slow path and de-opt, we need the monitor hanging around
3192 map()->push_monitor( flock );
3193
3194 const TypeFunc *tf = LockNode::lock_type();
3195 LockNode *lock = new LockNode(C, tf);
3196
3197 lock->init_req( TypeFunc::Control, control() );
3198 lock->init_req( TypeFunc::Memory , mem );
3199 lock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
3200 lock->init_req( TypeFunc::FramePtr, frameptr() );
3201 lock->init_req( TypeFunc::ReturnAdr, top() );
3202
3203 lock->init_req(TypeFunc::Parms + 0, obj);
3204 lock->init_req(TypeFunc::Parms + 1, box);
3205 lock->init_req(TypeFunc::Parms + 2, flock);
3206 add_safepoint_edges(lock);
3207
3208 lock = _gvn.transform( lock )->as_Lock();
3209
3210 // lock has no side-effects, sets few values
3211 set_predefined_output_for_runtime_call(lock, mem, TypeRawPtr::BOTTOM);
3212
3213 insert_mem_bar(Op_MemBarAcquireLock);
3214
3215 // Add this to the worklist so that the lock can be eliminated
3216 record_for_igvn(lock);
3217
3218 #ifndef PRODUCT
3219 if (PrintLockStatistics) {
3220 // Update the counter for this lock. Don't bother using an atomic
3221 // operation since we don't require absolute accuracy.
3222 lock->create_lock_counter(map()->jvms());
3223 increment_counter(lock->counter()->addr());
3224 }
3225 #endif
3226
3227 return flock;
3228 }
3229
3230
3231 //------------------------------shared_unlock----------------------------------
3232 // Emit unlocking code.
3233 void GraphKit::shared_unlock(Node* box, Node* obj) {
3234 // bci is either a monitorenter bc or InvocationEntryBci
3235 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
3236 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
3237
3238 if( !GenerateSynchronizationCode )
3239 return;
3240 if (stopped()) { // Dead monitor?
3241 map()->pop_monitor(); // Kill monitor from debug info
3242 return;
3243 }
3244
3245 // Memory barrier to avoid floating things down past the locked region
3246 insert_mem_bar(Op_MemBarReleaseLock);
3247
3248 const TypeFunc *tf = OptoRuntime::complete_monitor_exit_Type();
3249 UnlockNode *unlock = new UnlockNode(C, tf);
3250 #ifdef ASSERT
3251 unlock->set_dbg_jvms(sync_jvms());
3252 #endif
3253 uint raw_idx = Compile::AliasIdxRaw;
3254 unlock->init_req( TypeFunc::Control, control() );
3255 unlock->init_req( TypeFunc::Memory , memory(raw_idx) );
3256 unlock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
3257 unlock->init_req( TypeFunc::FramePtr, frameptr() );
3258 unlock->init_req( TypeFunc::ReturnAdr, top() );
3259
3260 unlock->init_req(TypeFunc::Parms + 0, obj);
3261 unlock->init_req(TypeFunc::Parms + 1, box);
3262 unlock = _gvn.transform(unlock)->as_Unlock();
3263
3264 Node* mem = reset_memory();
3265
3266 // unlock has no side-effects, sets few values
3267 set_predefined_output_for_runtime_call(unlock, mem, TypeRawPtr::BOTTOM);
3268
3269 // Kill monitor from debug info
3270 map()->pop_monitor( );
3271 }
3272
3273 //-------------------------------get_layout_helper-----------------------------
3274 // If the given klass is a constant or known to be an array,
3275 // fetch the constant layout helper value into constant_value
3276 // and return (Node*)NULL. Otherwise, load the non-constant
3277 // layout helper value, and return the node which represents it.
3278 // This two-faced routine is useful because allocation sites
3279 // almost always feature constant types.
3280 Node* GraphKit::get_layout_helper(Node* klass_node, jint& constant_value) {
3281 const TypeKlassPtr* inst_klass = _gvn.type(klass_node)->isa_klassptr();
3282 if (!StressReflectiveCode && inst_klass != NULL) {
3283 ciKlass* klass = inst_klass->klass();
3284 bool xklass = inst_klass->klass_is_exact();
3285 if (xklass || klass->is_array_klass()) {
3286 jint lhelper = klass->layout_helper();
3287 if (lhelper != Klass::_lh_neutral_value) {
3288 constant_value = lhelper;
3289 return (Node*) NULL;
3290 }
3291 }
3292 }
3293 constant_value = Klass::_lh_neutral_value; // put in a known value
3294 Node* lhp = basic_plus_adr(klass_node, klass_node, in_bytes(Klass::layout_helper_offset()));
3295 return make_load(NULL, lhp, TypeInt::INT, T_INT, MemNode::unordered);
3296 }
3297
3298 // We just put in an allocate/initialize with a big raw-memory effect.
3299 // Hook selected additional alias categories on the initialization.
3300 static void hook_memory_on_init(GraphKit& kit, int alias_idx,
3301 MergeMemNode* init_in_merge,
3302 Node* init_out_raw) {
3303 DEBUG_ONLY(Node* init_in_raw = init_in_merge->base_memory());
3304 assert(init_in_merge->memory_at(alias_idx) == init_in_raw, "");
3305
3306 Node* prevmem = kit.memory(alias_idx);
3307 init_in_merge->set_memory_at(alias_idx, prevmem);
3308 kit.set_memory(init_out_raw, alias_idx);
3309 }
3310
3311 //---------------------------set_output_for_allocation-------------------------
3312 Node* GraphKit::set_output_for_allocation(AllocateNode* alloc,
3313 const TypeOopPtr* oop_type,
3314 bool deoptimize_on_exception) {
3315 int rawidx = Compile::AliasIdxRaw;
3316 alloc->set_req( TypeFunc::FramePtr, frameptr() );
3317 add_safepoint_edges(alloc);
3318 Node* allocx = _gvn.transform(alloc);
3319 set_control( _gvn.transform(new ProjNode(allocx, TypeFunc::Control) ) );
3320 // create memory projection for i_o
3321 set_memory ( _gvn.transform( new ProjNode(allocx, TypeFunc::Memory, true) ), rawidx );
3322 make_slow_call_ex(allocx, env()->Throwable_klass(), true, deoptimize_on_exception);
3323
3324 // create a memory projection as for the normal control path
3325 Node* malloc = _gvn.transform(new ProjNode(allocx, TypeFunc::Memory));
3326 set_memory(malloc, rawidx);
3327
3328 // a normal slow-call doesn't change i_o, but an allocation does
3329 // we create a separate i_o projection for the normal control path
3330 set_i_o(_gvn.transform( new ProjNode(allocx, TypeFunc::I_O, false) ) );
3331 Node* rawoop = _gvn.transform( new ProjNode(allocx, TypeFunc::Parms) );
3332
3333 // put in an initialization barrier
3334 InitializeNode* init = insert_mem_bar_volatile(Op_Initialize, rawidx,
3335 rawoop)->as_Initialize();
3336 assert(alloc->initialization() == init, "2-way macro link must work");
3337 assert(init ->allocation() == alloc, "2-way macro link must work");
3338 {
3339 // Extract memory strands which may participate in the new object's
3340 // initialization, and source them from the new InitializeNode.
3341 // This will allow us to observe initializations when they occur,
3342 // and link them properly (as a group) to the InitializeNode.
3343 assert(init->in(InitializeNode::Memory) == malloc, "");
3344 MergeMemNode* minit_in = MergeMemNode::make(malloc);
3345 init->set_req(InitializeNode::Memory, minit_in);
3346 record_for_igvn(minit_in); // fold it up later, if possible
3347 Node* minit_out = memory(rawidx);
3348 assert(minit_out->is_Proj() && minit_out->in(0) == init, "");
3349 if (oop_type->isa_aryptr()) {
3350 const TypePtr* telemref = oop_type->add_offset(Type::OffsetBot);
3351 int elemidx = C->get_alias_index(telemref);
3352 hook_memory_on_init(*this, elemidx, minit_in, minit_out);
3353 } else if (oop_type->isa_instptr()) {
3354 ciInstanceKlass* ik = oop_type->klass()->as_instance_klass();
3355 for (int i = 0, len = ik->nof_nonstatic_fields(); i < len; i++) {
3356 ciField* field = ik->nonstatic_field_at(i);
3357 if (field->offset() >= TrackedInitializationLimit * HeapWordSize)
3358 continue; // do not bother to track really large numbers of fields
3359 // Find (or create) the alias category for this field:
3360 int fieldidx = C->alias_type(field)->index();
3361 hook_memory_on_init(*this, fieldidx, minit_in, minit_out);
3362 }
3363 }
3364 }
3365
3366 // Cast raw oop to the real thing...
3367 Node* javaoop = new CheckCastPPNode(control(), rawoop, oop_type);
3368 javaoop = _gvn.transform(javaoop);
3369 C->set_recent_alloc(control(), javaoop);
3370 assert(just_allocated_object(control()) == javaoop, "just allocated");
3371
3372 #ifdef ASSERT
3373 { // Verify that the AllocateNode::Ideal_allocation recognizers work:
3374 assert(AllocateNode::Ideal_allocation(rawoop, &_gvn) == alloc,
3375 "Ideal_allocation works");
3376 assert(AllocateNode::Ideal_allocation(javaoop, &_gvn) == alloc,
3377 "Ideal_allocation works");
3378 if (alloc->is_AllocateArray()) {
3379 assert(AllocateArrayNode::Ideal_array_allocation(rawoop, &_gvn) == alloc->as_AllocateArray(),
3380 "Ideal_allocation works");
3381 assert(AllocateArrayNode::Ideal_array_allocation(javaoop, &_gvn) == alloc->as_AllocateArray(),
3382 "Ideal_allocation works");
3383 } else {
3384 assert(alloc->in(AllocateNode::ALength)->is_top(), "no length, please");
3385 }
3386 }
3387 #endif //ASSERT
3388
3389 return javaoop;
3390 }
3391
3392 //---------------------------new_instance--------------------------------------
3393 // This routine takes a klass_node which may be constant (for a static type)
3394 // or may be non-constant (for reflective code). It will work equally well
3395 // for either, and the graph will fold nicely if the optimizer later reduces
3396 // the type to a constant.
3397 // The optional arguments are for specialized use by intrinsics:
3398 // - If 'extra_slow_test' if not null is an extra condition for the slow-path.
3399 // - If 'return_size_val', report the the total object size to the caller.
3400 // - deoptimize_on_exception controls how Java exceptions are handled (rethrow vs deoptimize)
3401 Node* GraphKit::new_instance(Node* klass_node,
3402 Node* extra_slow_test,
3403 Node* *return_size_val,
3404 bool deoptimize_on_exception) {
3405 // Compute size in doublewords
3406 // The size is always an integral number of doublewords, represented
3407 // as a positive bytewise size stored in the klass's layout_helper.
3408 // The layout_helper also encodes (in a low bit) the need for a slow path.
3409 jint layout_con = Klass::_lh_neutral_value;
3410 Node* layout_val = get_layout_helper(klass_node, layout_con);
3411 int layout_is_con = (layout_val == NULL);
3412
3413 if (extra_slow_test == NULL) extra_slow_test = intcon(0);
3414 // Generate the initial go-slow test. It's either ALWAYS (return a
3415 // Node for 1) or NEVER (return a NULL) or perhaps (in the reflective
3416 // case) a computed value derived from the layout_helper.
3417 Node* initial_slow_test = NULL;
3418 if (layout_is_con) {
3419 assert(!StressReflectiveCode, "stress mode does not use these paths");
3420 bool must_go_slow = Klass::layout_helper_needs_slow_path(layout_con);
3421 initial_slow_test = must_go_slow? intcon(1): extra_slow_test;
3422
3423 } else { // reflective case
3424 // This reflective path is used by Unsafe.allocateInstance.
3425 // (It may be stress-tested by specifying StressReflectiveCode.)
3426 // Basically, we want to get into the VM is there's an illegal argument.
3427 Node* bit = intcon(Klass::_lh_instance_slow_path_bit);
3428 initial_slow_test = _gvn.transform( new AndINode(layout_val, bit) );
3429 if (extra_slow_test != intcon(0)) {
3430 initial_slow_test = _gvn.transform( new OrINode(initial_slow_test, extra_slow_test) );
3431 }
3432 // (Macro-expander will further convert this to a Bool, if necessary.)
3433 }
3434
3435 // Find the size in bytes. This is easy; it's the layout_helper.
3436 // The size value must be valid even if the slow path is taken.
3437 Node* size = NULL;
3438 if (layout_is_con) {
3439 size = MakeConX(Klass::layout_helper_size_in_bytes(layout_con));
3440 } else { // reflective case
3441 // This reflective path is used by clone and Unsafe.allocateInstance.
3442 size = ConvI2X(layout_val);
3443
3444 // Clear the low bits to extract layout_helper_size_in_bytes:
3445 assert((int)Klass::_lh_instance_slow_path_bit < BytesPerLong, "clear bit");
3446 Node* mask = MakeConX(~ (intptr_t)right_n_bits(LogBytesPerLong));
3447 size = _gvn.transform( new AndXNode(size, mask) );
3448 }
3449 if (return_size_val != NULL) {
3450 (*return_size_val) = size;
3451 }
3452
3453 // This is a precise notnull oop of the klass.
3454 // (Actually, it need not be precise if this is a reflective allocation.)
3455 // It's what we cast the result to.
3456 const TypeKlassPtr* tklass = _gvn.type(klass_node)->isa_klassptr();
3457 if (!tklass) tklass = TypeKlassPtr::OBJECT;
3458 const TypeOopPtr* oop_type = tklass->as_instance_type();
3459
3460 // Now generate allocation code
3461
3462 // The entire memory state is needed for slow path of the allocation
3463 // since GC and deoptimization can happened.
3464 Node *mem = reset_memory();
3465 set_all_memory(mem); // Create new memory state
3466
3467 AllocateNode* alloc = new AllocateNode(C, AllocateNode::alloc_type(Type::TOP),
3468 control(), mem, i_o(),
3469 size, klass_node,
3470 initial_slow_test);
3471
3472 return set_output_for_allocation(alloc, oop_type, deoptimize_on_exception);
3473 }
3474
3475 //-------------------------------new_array-------------------------------------
3476 // helper for both newarray and anewarray
3477 // The 'length' parameter is (obviously) the length of the array.
3478 // See comments on new_instance for the meaning of the other arguments.
3479 Node* GraphKit::new_array(Node* klass_node, // array klass (maybe variable)
3480 Node* length, // number of array elements
3481 int nargs, // number of arguments to push back for uncommon trap
3482 Node* *return_size_val,
3483 bool deoptimize_on_exception) {
3484 jint layout_con = Klass::_lh_neutral_value;
3485 Node* layout_val = get_layout_helper(klass_node, layout_con);
3486 int layout_is_con = (layout_val == NULL);
3487
3488 if (!layout_is_con && !StressReflectiveCode &&
3489 !too_many_traps(Deoptimization::Reason_class_check)) {
3490 // This is a reflective array creation site.
3491 // Optimistically assume that it is a subtype of Object[],
3492 // so that we can fold up all the address arithmetic.
3493 layout_con = Klass::array_layout_helper(T_OBJECT);
3494 Node* cmp_lh = _gvn.transform( new CmpINode(layout_val, intcon(layout_con)) );
3495 Node* bol_lh = _gvn.transform( new BoolNode(cmp_lh, BoolTest::eq) );
3496 { BuildCutout unless(this, bol_lh, PROB_MAX);
3497 inc_sp(nargs);
3498 uncommon_trap(Deoptimization::Reason_class_check,
3499 Deoptimization::Action_maybe_recompile);
3500 }
3501 layout_val = NULL;
3502 layout_is_con = true;
3503 }
3504
3505 // Generate the initial go-slow test. Make sure we do not overflow
3506 // if length is huge (near 2Gig) or negative! We do not need
3507 // exact double-words here, just a close approximation of needed
3508 // double-words. We can't add any offset or rounding bits, lest we
3509 // take a size -1 of bytes and make it positive. Use an unsigned
3510 // compare, so negative sizes look hugely positive.
3511 int fast_size_limit = FastAllocateSizeLimit;
3512 if (layout_is_con) {
3513 assert(!StressReflectiveCode, "stress mode does not use these paths");
3514 // Increase the size limit if we have exact knowledge of array type.
3515 int log2_esize = Klass::layout_helper_log2_element_size(layout_con);
3516 fast_size_limit <<= (LogBytesPerLong - log2_esize);
3517 }
3518
3519 Node* initial_slow_cmp = _gvn.transform( new CmpUNode( length, intcon( fast_size_limit ) ) );
3520 Node* initial_slow_test = _gvn.transform( new BoolNode( initial_slow_cmp, BoolTest::gt ) );
3521 if (initial_slow_test->is_Bool()) {
3522 // Hide it behind a CMoveI, or else PhaseIdealLoop::split_up will get sick.
3523 initial_slow_test = initial_slow_test->as_Bool()->as_int_value(&_gvn);
3524 }
3525
3526 // --- Size Computation ---
3527 // array_size = round_to_heap(array_header + (length << elem_shift));
3528 // where round_to_heap(x) == round_to(x, MinObjAlignmentInBytes)
3529 // and round_to(x, y) == ((x + y-1) & ~(y-1))
3530 // The rounding mask is strength-reduced, if possible.
3531 int round_mask = MinObjAlignmentInBytes - 1;
3532 Node* header_size = NULL;
3533 int header_size_min = arrayOopDesc::base_offset_in_bytes(T_BYTE);
3534 // (T_BYTE has the weakest alignment and size restrictions...)
3535 if (layout_is_con) {
3536 int hsize = Klass::layout_helper_header_size(layout_con);
3537 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3538 BasicType etype = Klass::layout_helper_element_type(layout_con);
3539 if ((round_mask & ~right_n_bits(eshift)) == 0)
3540 round_mask = 0; // strength-reduce it if it goes away completely
3541 assert((hsize & right_n_bits(eshift)) == 0, "hsize is pre-rounded");
3542 assert(header_size_min <= hsize, "generic minimum is smallest");
3543 header_size_min = hsize;
3544 header_size = intcon(hsize + round_mask);
3545 } else {
3546 Node* hss = intcon(Klass::_lh_header_size_shift);
3547 Node* hsm = intcon(Klass::_lh_header_size_mask);
3548 Node* hsize = _gvn.transform( new URShiftINode(layout_val, hss) );
3549 hsize = _gvn.transform( new AndINode(hsize, hsm) );
3550 Node* mask = intcon(round_mask);
3551 header_size = _gvn.transform( new AddINode(hsize, mask) );
3552 }
3553
3554 Node* elem_shift = NULL;
3555 if (layout_is_con) {
3556 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3557 if (eshift != 0)
3558 elem_shift = intcon(eshift);
3559 } else {
3560 // There is no need to mask or shift this value.
3561 // The semantics of LShiftINode include an implicit mask to 0x1F.
3562 assert(Klass::_lh_log2_element_size_shift == 0, "use shift in place");
3563 elem_shift = layout_val;
3564 }
3565
3566 // Transition to native address size for all offset calculations:
3567 Node* lengthx = ConvI2X(length);
3568 Node* headerx = ConvI2X(header_size);
3569 #ifdef _LP64
3570 { const TypeLong* tllen = _gvn.find_long_type(lengthx);
3571 if (tllen != NULL && tllen->_lo < 0) {
3572 // Add a manual constraint to a positive range. Cf. array_element_address.
3573 jlong size_max = arrayOopDesc::max_array_length(T_BYTE);
3574 if (size_max > tllen->_hi) size_max = tllen->_hi;
3575 const TypeLong* tlcon = TypeLong::make(CONST64(0), size_max, Type::WidenMin);
3576 lengthx = _gvn.transform( new ConvI2LNode(length, tlcon));
3577 }
3578 }
3579 #endif
3580
3581 // Combine header size (plus rounding) and body size. Then round down.
3582 // This computation cannot overflow, because it is used only in two
3583 // places, one where the length is sharply limited, and the other
3584 // after a successful allocation.
3585 Node* abody = lengthx;
3586 if (elem_shift != NULL)
3587 abody = _gvn.transform( new LShiftXNode(lengthx, elem_shift) );
3588 Node* size = _gvn.transform( new AddXNode(headerx, abody) );
3589 if (round_mask != 0) {
3590 Node* mask = MakeConX(~round_mask);
3591 size = _gvn.transform( new AndXNode(size, mask) );
3592 }
3593 // else if round_mask == 0, the size computation is self-rounding
3594
3595 if (return_size_val != NULL) {
3596 // This is the size
3597 (*return_size_val) = size;
3598 }
3599
3600 // Now generate allocation code
3601
3602 // The entire memory state is needed for slow path of the allocation
3603 // since GC and deoptimization can happened.
3604 Node *mem = reset_memory();
3605 set_all_memory(mem); // Create new memory state
3606
3607 // Create the AllocateArrayNode and its result projections
3608 AllocateArrayNode* alloc
3609 = new AllocateArrayNode(C, AllocateArrayNode::alloc_type(TypeInt::INT),
3610 control(), mem, i_o(),
3611 size, klass_node,
3612 initial_slow_test,
3613 length);
3614
3615 // Cast to correct type. Note that the klass_node may be constant or not,
3616 // and in the latter case the actual array type will be inexact also.
3617 // (This happens via a non-constant argument to inline_native_newArray.)
3618 // In any case, the value of klass_node provides the desired array type.
3619 const TypeInt* length_type = _gvn.find_int_type(length);
3620 const TypeOopPtr* ary_type = _gvn.type(klass_node)->is_klassptr()->as_instance_type();
3621 if (ary_type->isa_aryptr() && length_type != NULL) {
3622 // Try to get a better type than POS for the size
3623 ary_type = ary_type->is_aryptr()->cast_to_size(length_type);
3624 }
3625
3626 Node* javaoop = set_output_for_allocation(alloc, ary_type, deoptimize_on_exception);
3627
3628 // Cast length on remaining path to be as narrow as possible
3629 if (map()->find_edge(length) >= 0) {
3630 Node* ccast = alloc->make_ideal_length(ary_type, &_gvn);
3631 if (ccast != length) {
3632 _gvn.set_type_bottom(ccast);
3633 record_for_igvn(ccast);
3634 replace_in_map(length, ccast);
3635 }
3636 }
3637
3638 return javaoop;
3639 }
3640
3641 // The following "Ideal_foo" functions are placed here because they recognize
3642 // the graph shapes created by the functions immediately above.
3643
3644 //---------------------------Ideal_allocation----------------------------------
3645 // Given an oop pointer or raw pointer, see if it feeds from an AllocateNode.
3646 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase) {
3647 if (ptr == NULL) { // reduce dumb test in callers
3648 return NULL;
3649 }
3650
3651 // Attempt to see through Shenandoah barriers.
3652 ptr = ShenandoahBarrierNode::skip_through_barrier(ptr);
3653
3654 if (ptr->is_CheckCastPP()) { // strip only one raw-to-oop cast
3655 ptr = ptr->in(1);
3656 if (ptr == NULL) return NULL;
3657 }
3658 // Return NULL for allocations with several casts:
3659 // j.l.reflect.Array.newInstance(jobject, jint)
3660 // Object.clone()
3661 // to keep more precise type from last cast.
3662 if (ptr->is_Proj()) {
3663 Node* allo = ptr->in(0);
3664 if (allo != NULL && allo->is_Allocate()) {
3665 return allo->as_Allocate();
3666 }
3667 }
3668 // Report failure to match.
3669 return NULL;
3670 }
3671
3672 // Fancy version which also strips off an offset (and reports it to caller).
3673 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase,
3674 intptr_t& offset) {
3675 Node* base = AddPNode::Ideal_base_and_offset(ptr, phase, offset);
3676 if (base == NULL) return NULL;
3677 return Ideal_allocation(base, phase);
3678 }
3679
3680 // Trace Initialize <- Proj[Parm] <- Allocate
3681 AllocateNode* InitializeNode::allocation() {
3682 Node* rawoop = in(InitializeNode::RawAddress);
3683 if (rawoop->is_Proj()) {
3684 Node* alloc = rawoop->in(0);
3685 if (alloc->is_Allocate()) {
3686 return alloc->as_Allocate();
3687 }
3688 }
3689 return NULL;
3690 }
3691
3692 // Trace Allocate -> Proj[Parm] -> Initialize
3693 InitializeNode* AllocateNode::initialization() {
3694 ProjNode* rawoop = proj_out(AllocateNode::RawAddress);
3695 if (rawoop == NULL) return NULL;
3696 for (DUIterator_Fast imax, i = rawoop->fast_outs(imax); i < imax; i++) {
3697 Node* init = rawoop->fast_out(i);
3698 if (init->is_Initialize()) {
3699 assert(init->as_Initialize()->allocation() == this, "2-way link");
3700 return init->as_Initialize();
3701 }
3702 }
3703 return NULL;
3704 }
3705
3706 //----------------------------- loop predicates ---------------------------
3707
3708 //------------------------------add_predicate_impl----------------------------
3709 void GraphKit::add_predicate_impl(Deoptimization::DeoptReason reason, int nargs) {
3710 // Too many traps seen?
3711 if (too_many_traps(reason)) {
3712 #ifdef ASSERT
3713 if (TraceLoopPredicate) {
3714 int tc = C->trap_count(reason);
3715 tty->print("too many traps=%s tcount=%d in ",
3716 Deoptimization::trap_reason_name(reason), tc);
3717 method()->print(); // which method has too many predicate traps
3718 tty->cr();
3719 }
3720 #endif
3721 // We cannot afford to take more traps here,
3722 // do not generate predicate.
3723 return;
3724 }
3725
3726 Node *cont = _gvn.intcon(1);
3727 Node* opq = _gvn.transform(new Opaque1Node(C, cont));
3728 Node *bol = _gvn.transform(new Conv2BNode(opq));
3729 IfNode* iff = create_and_map_if(control(), bol, PROB_MAX, COUNT_UNKNOWN);
3730 Node* iffalse = _gvn.transform(new IfFalseNode(iff));
3731 C->add_predicate_opaq(opq);
3732 {
3733 PreserveJVMState pjvms(this);
3734 set_control(iffalse);
3735 inc_sp(nargs);
3736 uncommon_trap(reason, Deoptimization::Action_maybe_recompile);
3737 }
3738 Node* iftrue = _gvn.transform(new IfTrueNode(iff));
3739 set_control(iftrue);
3740 }
3741
3742 //------------------------------add_predicate---------------------------------
3743 void GraphKit::add_predicate(int nargs) {
3744 if (UseLoopPredicate) {
3745 add_predicate_impl(Deoptimization::Reason_predicate, nargs);
3746 }
3747 // loop's limit check predicate should be near the loop.
3748 if (LoopLimitCheck) {
3749 add_predicate_impl(Deoptimization::Reason_loop_limit_check, nargs);
3750 }
3751 }
3752
3753 //----------------------------- store barriers ----------------------------
3754 #define __ ideal.
3755
3756 void GraphKit::sync_kit(IdealKit& ideal) {
3757 set_all_memory(__ merged_memory());
3758 set_i_o(__ i_o());
3759 set_control(__ ctrl());
3760 }
3761
3762 void GraphKit::final_sync(IdealKit& ideal) {
3763 // Final sync IdealKit and graphKit.
3764 sync_kit(ideal);
3765 }
3766
3767 Node* GraphKit::byte_map_base_node() {
3768 // Get base of card map
3769 CardTableModRefBS* ct =
3770 barrier_set_cast<CardTableModRefBS>(Universe::heap()->barrier_set());
3771 assert(sizeof(*ct->byte_map_base) == sizeof(jbyte), "adjust users of this code");
3772 if (ct->byte_map_base != NULL) {
3773 return makecon(TypeRawPtr::make((address)ct->byte_map_base));
3774 } else {
3775 return null();
3776 }
3777 }
3778
3779 // vanilla/CMS post barrier
3780 // Insert a write-barrier store. This is to let generational GC work; we have
3781 // to flag all oop-stores before the next GC point.
3782 void GraphKit::write_barrier_post(Node* oop_store,
3783 Node* obj,
3784 Node* adr,
3785 uint adr_idx,
3786 Node* val,
3787 bool use_precise) {
3788 // No store check needed if we're storing a NULL or an old object
3789 // (latter case is probably a string constant). The concurrent
3790 // mark sweep garbage collector, however, needs to have all nonNull
3791 // oop updates flagged via card-marks.
3792 if (val != NULL && val->is_Con()) {
3793 // must be either an oop or NULL
3794 const Type* t = val->bottom_type();
3795 if (t == TypePtr::NULL_PTR || t == Type::TOP)
3796 // stores of null never (?) need barriers
3797 return;
3798 }
3799
3800 if (use_ReduceInitialCardMarks()
3801 && obj == just_allocated_object(control())) {
3802 // We can skip marks on a freshly-allocated object in Eden.
3803 // Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
3804 // That routine informs GC to take appropriate compensating steps,
3805 // upon a slow-path allocation, so as to make this card-mark
3806 // elision safe.
3807 return;
3808 }
3809
3810 if (!use_precise) {
3811 // All card marks for a (non-array) instance are in one place:
3812 adr = obj;
3813 }
3814 // (Else it's an array (or unknown), and we want more precise card marks.)
3815 assert(adr != NULL, "");
3816
3817 IdealKit ideal(this, true);
3818
3819 // Convert the pointer to an int prior to doing math on it
3820 Node* cast = __ CastPX(__ ctrl(), adr);
3821
3822 // Divide by card size
3823 assert(Universe::heap()->barrier_set()->is_a(BarrierSet::CardTableModRef),
3824 "Only one we handle so far.");
3825 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
3826
3827 // Combine card table base and card offset
3828 Node* card_adr = __ AddP(__ top(), byte_map_base_node(), card_offset );
3829
3830 // Get the alias_index for raw card-mark memory
3831 int adr_type = Compile::AliasIdxRaw;
3832 Node* zero = __ ConI(0); // Dirty card value
3833 BasicType bt = T_BYTE;
3834
3835 if (UseConcMarkSweepGC && UseCondCardMark) {
3836 insert_mem_bar(Op_MemBarVolatile); // StoreLoad barrier
3837 __ sync_kit(this);
3838 }
3839
3840 if (UseCondCardMark) {
3841 // The classic GC reference write barrier is typically implemented
3842 // as a store into the global card mark table. Unfortunately
3843 // unconditional stores can result in false sharing and excessive
3844 // coherence traffic as well as false transactional aborts.
3845 // UseCondCardMark enables MP "polite" conditional card mark
3846 // stores. In theory we could relax the load from ctrl() to
3847 // no_ctrl, but that doesn't buy much latitude.
3848 Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, bt, adr_type);
3849 __ if_then(card_val, BoolTest::ne, zero);
3850 }
3851
3852 // Smash zero into card
3853 if( !UseConcMarkSweepGC ) {
3854 __ store(__ ctrl(), card_adr, zero, bt, adr_type, MemNode::unordered);
3855 } else {
3856 // Specialized path for CM store barrier
3857 __ storeCM(__ ctrl(), card_adr, zero, oop_store, adr_idx, bt, adr_type);
3858 }
3859
3860 if (UseCondCardMark) {
3861 __ end_if();
3862 }
3863
3864 // Final sync IdealKit and GraphKit.
3865 final_sync(ideal);
3866 }
3867 /*
3868 * Determine if the G1 pre-barrier can be removed. The pre-barrier is
3869 * required by SATB to make sure all objects live at the start of the
3870 * marking are kept alive, all reference updates need to any previous
3871 * reference stored before writing.
3872 *
3873 * If the previous value is NULL there is no need to save the old value.
3874 * References that are NULL are filtered during runtime by the barrier
3875 * code to avoid unnecessary queuing.
3876 *
3877 * However in the case of newly allocated objects it might be possible to
3878 * prove that the reference about to be overwritten is NULL during compile
3879 * time and avoid adding the barrier code completely.
3880 *
3881 * The compiler needs to determine that the object in which a field is about
3882 * to be written is newly allocated, and that no prior store to the same field
3883 * has happened since the allocation.
3884 *
3885 * Returns true if the pre-barrier can be removed
3886 */
3887 bool GraphKit::g1_can_remove_pre_barrier(PhaseTransform* phase, Node* adr,
3888 BasicType bt, uint adr_idx) {
3889 intptr_t offset = 0;
3890 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
3891 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
3892
3893 if (offset == Type::OffsetBot) {
3894 return false; // cannot unalias unless there are precise offsets
3895 }
3896
3897 if (alloc == NULL) {
3898 return false; // No allocation found
3899 }
3900
3901 intptr_t size_in_bytes = type2aelembytes(bt);
3902
3903 Node* mem = memory(adr_idx); // start searching here...
3904
3905 for (int cnt = 0; cnt < 50; cnt++) {
3906
3907 if (mem->is_Store()) {
3908
3909 Node* st_adr = mem->in(MemNode::Address);
3910 intptr_t st_offset = 0;
3911 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
3912
3913 if (st_base == NULL) {
3914 break; // inscrutable pointer
3915 }
3916
3917 // Break we have found a store with same base and offset as ours so break
3918 if (st_base == base && st_offset == offset) {
3919 break;
3920 }
3921
3922 if (st_offset != offset && st_offset != Type::OffsetBot) {
3923 const int MAX_STORE = BytesPerLong;
3924 if (st_offset >= offset + size_in_bytes ||
3925 st_offset <= offset - MAX_STORE ||
3926 st_offset <= offset - mem->as_Store()->memory_size()) {
3927 // Success: The offsets are provably independent.
3928 // (You may ask, why not just test st_offset != offset and be done?
3929 // The answer is that stores of different sizes can co-exist
3930 // in the same sequence of RawMem effects. We sometimes initialize
3931 // a whole 'tile' of array elements with a single jint or jlong.)
3932 mem = mem->in(MemNode::Memory);
3933 continue; // advance through independent store memory
3934 }
3935 }
3936
3937 if (st_base != base
3938 && MemNode::detect_ptr_independence(base, alloc, st_base,
3939 AllocateNode::Ideal_allocation(st_base, phase),
3940 phase)) {
3941 // Success: The bases are provably independent.
3942 mem = mem->in(MemNode::Memory);
3943 continue; // advance through independent store memory
3944 }
3945 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
3946
3947 InitializeNode* st_init = mem->in(0)->as_Initialize();
3948 AllocateNode* st_alloc = st_init->allocation();
3949
3950 // Make sure that we are looking at the same allocation site.
3951 // The alloc variable is guaranteed to not be null here from earlier check.
3952 if (alloc == st_alloc) {
3953 // Check that the initialization is storing NULL so that no previous store
3954 // has been moved up and directly write a reference
3955 Node* captured_store = st_init->find_captured_store(offset,
3956 type2aelembytes(T_OBJECT),
3957 phase);
3958 if (captured_store == NULL || captured_store == st_init->zero_memory()) {
3959 return true;
3960 }
3961 }
3962 }
3963
3964 // Unless there is an explicit 'continue', we must bail out here,
3965 // because 'mem' is an inscrutable memory state (e.g., a call).
3966 break;
3967 }
3968
3969 return false;
3970 }
3971
3972 // G1 pre/post barriers
3973 void GraphKit::g1_write_barrier_pre(bool do_load,
3974 Node* obj,
3975 Node* adr,
3976 uint alias_idx,
3977 Node* val,
3978 const TypeOopPtr* val_type,
3979 Node* pre_val,
3980 BasicType bt) {
3981
3982 // Some sanity checks
3983 // Note: val is unused in this routine.
3984
3985 if (do_load) {
3986 // We need to generate the load of the previous value
3987 assert(obj != NULL, "must have a base");
3988 assert(adr != NULL, "where are loading from?");
3989 assert(pre_val == NULL, "loaded already?");
3990 assert(val_type != NULL, "need a type");
3991
3992 if (use_ReduceInitialCardMarks()
3993 && g1_can_remove_pre_barrier(&_gvn, adr, bt, alias_idx)) {
3994 return;
3995 }
3996
3997 } else {
3998 // In this case both val_type and alias_idx are unused.
3999 assert(pre_val != NULL, "must be loaded already");
4000 // Nothing to be done if pre_val is null.
4001 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
4002 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
4003 }
4004 assert(bt == T_OBJECT, "or we shouldn't be here");
4005
4006 IdealKit ideal(this, true);
4007
4008 Node* tls = __ thread(); // ThreadLocalStorage
4009
4010 Node* no_ctrl = NULL;
4011 Node* no_base = __ top();
4012 Node* zero = __ ConI(0);
4013 Node* zeroX = __ ConX(0);
4014
4015 float likely = PROB_LIKELY(0.999);
4016 float unlikely = PROB_UNLIKELY(0.999);
4017
4018 BasicType active_type = in_bytes(PtrQueue::byte_width_of_active()) == 4 ? T_INT : T_BYTE;
4019 assert(in_bytes(PtrQueue::byte_width_of_active()) == 4 || in_bytes(PtrQueue::byte_width_of_active()) == 1, "flag width");
4020
4021 // Offsets into the thread
4022 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 648
4023 PtrQueue::byte_offset_of_active());
4024 const int index_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 656
4025 PtrQueue::byte_offset_of_index());
4026 const int buffer_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 652
4027 PtrQueue::byte_offset_of_buf());
4028
4029 // Now the actual pointers into the thread
4030 Node* marking_adr = __ AddP(no_base, tls, __ ConX(marking_offset));
4031 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
4032 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
4033
4034 // Now some of the values
4035 Node* marking = __ load(__ ctrl(), marking_adr, TypeInt::INT, active_type, Compile::AliasIdxRaw);
4036
4037 // if (!marking)
4038 __ if_then(marking, BoolTest::ne, zero, unlikely); {
4039 BasicType index_bt = TypeX_X->basic_type();
4040 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 PtrQueue::_index with wrong size.");
4041 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
4042
4043 if (do_load) {
4044 // load original value
4045 // alias_idx correct??
4046 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
4047 }
4048
4049 // if (pre_val != NULL)
4050 __ if_then(pre_val, BoolTest::ne, null()); {
4051 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
4052
4053 // is the queue for this thread full?
4054 __ if_then(index, BoolTest::ne, zeroX, likely); {
4055
4056 // decrement the index
4057 Node* next_index = _gvn.transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
4058
4059 // Now get the buffer location we will log the previous value into and store it
4060 Node *log_addr = __ AddP(no_base, buffer, next_index);
4061 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
4062 // update the index
4063 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
4064
4065 } __ else_(); {
4066
4067 // logging buffer is full, call the runtime
4068 const TypeFunc *tf = OptoRuntime::g1_wb_pre_Type();
4069 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), "g1_wb_pre", pre_val, tls);
4070 } __ end_if(); // (!index)
4071 } __ end_if(); // (pre_val != NULL)
4072 } __ end_if(); // (!marking)
4073
4074 // Final sync IdealKit and GraphKit.
4075 final_sync(ideal);
4076 }
4077
4078 /*
4079 * G1 similar to any GC with a Young Generation requires a way to keep track of
4080 * references from Old Generation to Young Generation to make sure all live
4081 * objects are found. G1 also requires to keep track of object references
4082 * between different regions to enable evacuation of old regions, which is done
4083 * as part of mixed collections. References are tracked in remembered sets and
4084 * is continuously updated as reference are written to with the help of the
4085 * post-barrier.
4086 *
4087 * To reduce the number of updates to the remembered set the post-barrier
4088 * filters updates to fields in objects located in the Young Generation,
4089 * the same region as the reference, when the NULL is being written or
4090 * if the card is already marked as dirty by an earlier write.
4091 *
4092 * Under certain circumstances it is possible to avoid generating the
4093 * post-barrier completely if it is possible during compile time to prove
4094 * the object is newly allocated and that no safepoint exists between the
4095 * allocation and the store.
4096 *
4097 * In the case of slow allocation the allocation code must handle the barrier
4098 * as part of the allocation in the case the allocated object is not located
4099 * in the nursery, this would happen for humongous objects. This is similar to
4100 * how CMS is required to handle this case, see the comments for the method
4101 * CollectedHeap::new_store_pre_barrier and OptoRuntime::new_store_pre_barrier.
4102 * A deferred card mark is required for these objects and handled in the above
4103 * mentioned methods.
4104 *
4105 * Returns true if the post barrier can be removed
4106 */
4107 bool GraphKit::g1_can_remove_post_barrier(PhaseTransform* phase, Node* store,
4108 Node* adr) {
4109 intptr_t offset = 0;
4110 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
4111 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
4112
4113 if (offset == Type::OffsetBot) {
4114 return false; // cannot unalias unless there are precise offsets
4115 }
4116
4117 if (alloc == NULL) {
4118 return false; // No allocation found
4119 }
4120
4121 // Start search from Store node
4122 Node* mem = store->in(MemNode::Control);
4123 if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
4124
4125 InitializeNode* st_init = mem->in(0)->as_Initialize();
4126 AllocateNode* st_alloc = st_init->allocation();
4127
4128 // Make sure we are looking at the same allocation
4129 if (alloc == st_alloc) {
4130 return true;
4131 }
4132 }
4133
4134 return false;
4135 }
4136
4137 //
4138 // Update the card table and add card address to the queue
4139 //
4140 void GraphKit::g1_mark_card(IdealKit& ideal,
4141 Node* card_adr,
4142 Node* oop_store,
4143 uint oop_alias_idx,
4144 Node* index,
4145 Node* index_adr,
4146 Node* buffer,
4147 const TypeFunc* tf) {
4148
4149 Node* zero = __ ConI(0);
4150 Node* zeroX = __ ConX(0);
4151 Node* no_base = __ top();
4152 BasicType card_bt = T_BYTE;
4153 // Smash zero into card. MUST BE ORDERED WRT TO STORE
4154 __ storeCM(__ ctrl(), card_adr, zero, oop_store, oop_alias_idx, card_bt, Compile::AliasIdxRaw);
4155
4156 // Now do the queue work
4157 __ if_then(index, BoolTest::ne, zeroX); {
4158
4159 Node* next_index = _gvn.transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
4160 Node* log_addr = __ AddP(no_base, buffer, next_index);
4161
4162 // Order, see storeCM.
4163 __ store(__ ctrl(), log_addr, card_adr, T_ADDRESS, Compile::AliasIdxRaw, MemNode::unordered);
4164 __ store(__ ctrl(), index_adr, next_index, TypeX_X->basic_type(), Compile::AliasIdxRaw, MemNode::unordered);
4165
4166 } __ else_(); {
4167 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), "g1_wb_post", card_adr, __ thread());
4168 } __ end_if();
4169
4170 }
4171
4172 void GraphKit::g1_write_barrier_post(Node* oop_store,
4173 Node* obj,
4174 Node* adr,
4175 uint alias_idx,
4176 Node* val,
4177 BasicType bt,
4178 bool use_precise) {
4179 // If we are writing a NULL then we need no post barrier
4180
4181 if (val != NULL && val->is_Con() && val->bottom_type() == TypePtr::NULL_PTR) {
4182 // Must be NULL
4183 const Type* t = val->bottom_type();
4184 assert(t == Type::TOP || t == TypePtr::NULL_PTR, "must be NULL");
4185 // No post barrier if writing NULLx
4186 return;
4187 }
4188
4189 if (use_ReduceInitialCardMarks() && obj == just_allocated_object(control())) {
4190 // We can skip marks on a freshly-allocated object in Eden.
4191 // Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
4192 // That routine informs GC to take appropriate compensating steps,
4193 // upon a slow-path allocation, so as to make this card-mark
4194 // elision safe.
4195 return;
4196 }
4197
4198 if (use_ReduceInitialCardMarks()
4199 && g1_can_remove_post_barrier(&_gvn, oop_store, adr)) {
4200 return;
4201 }
4202
4203 if (!use_precise) {
4204 // All card marks for a (non-array) instance are in one place:
4205 adr = obj;
4206 }
4207 // (Else it's an array (or unknown), and we want more precise card marks.)
4208 assert(adr != NULL, "");
4209
4210 IdealKit ideal(this, true);
4211
4212 Node* tls = __ thread(); // ThreadLocalStorage
4213
4214 Node* no_base = __ top();
4215 float likely = PROB_LIKELY(0.999);
4216 float unlikely = PROB_UNLIKELY(0.999);
4217 Node* young_card = __ ConI((jint)G1SATBCardTableModRefBS::g1_young_card_val());
4218 Node* dirty_card = __ ConI((jint)CardTableModRefBS::dirty_card_val());
4219 Node* zeroX = __ ConX(0);
4220
4221 // Get the alias_index for raw card-mark memory
4222 const TypePtr* card_type = TypeRawPtr::BOTTOM;
4223
4224 const TypeFunc *tf = OptoRuntime::g1_wb_post_Type();
4225
4226 // Offsets into the thread
4227 const int index_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
4228 PtrQueue::byte_offset_of_index());
4229 const int buffer_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
4230 PtrQueue::byte_offset_of_buf());
4231
4232 // Pointers into the thread
4233
4234 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
4235 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
4236
4237 // Now some values
4238 // Use ctrl to avoid hoisting these values past a safepoint, which could
4239 // potentially reset these fields in the JavaThread.
4240 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, TypeX_X->basic_type(), Compile::AliasIdxRaw);
4241 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
4242
4243 // Convert the store obj pointer to an int prior to doing math on it
4244 // Must use ctrl to prevent "integerized oop" existing across safepoint
4245 Node* cast = __ CastPX(__ ctrl(), adr);
4246
4247 // Divide pointer by card size
4248 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
4249
4250 // Combine card table base and card offset
4251 Node* card_adr = __ AddP(no_base, byte_map_base_node(), card_offset );
4252
4253 // If we know the value being stored does it cross regions?
4254
4255 if (val != NULL) {
4256 // Does the store cause us to cross regions?
4257
4258 // Should be able to do an unsigned compare of region_size instead of
4259 // and extra shift. Do we have an unsigned compare??
4260 // Node* region_size = __ ConI(1 << HeapRegion::LogOfHRGrainBytes);
4261 Node* xor_res = __ URShiftX ( __ XorX( cast, __ CastPX(__ ctrl(), val)), __ ConI(HeapRegion::LogOfHRGrainBytes));
4262
4263 // if (xor_res == 0) same region so skip
4264 __ if_then(xor_res, BoolTest::ne, zeroX); {
4265
4266 // No barrier if we are storing a NULL
4267 __ if_then(val, BoolTest::ne, null(), unlikely); {
4268
4269 // Ok must mark the card if not already dirty
4270
4271 // load the original value of the card
4272 Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
4273
4274 __ if_then(card_val, BoolTest::ne, young_card); {
4275 sync_kit(ideal);
4276 // Use Op_MemBarVolatile to achieve the effect of a StoreLoad barrier.
4277 insert_mem_bar(Op_MemBarVolatile, oop_store);
4278 __ sync_kit(this);
4279
4280 Node* card_val_reload = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
4281 __ if_then(card_val_reload, BoolTest::ne, dirty_card); {
4282 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
4283 } __ end_if();
4284 } __ end_if();
4285 } __ end_if();
4286 } __ end_if();
4287 } else {
4288 // Object.clone() instrinsic uses this path.
4289 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
4290 }
4291
4292 // Final sync IdealKit and GraphKit.
4293 final_sync(ideal);
4294 }
4295 #undef __
4296
4297
4298
4299 Node* GraphKit::load_String_offset(Node* ctrl, Node* str) {
4300 if (java_lang_String::has_offset_field()) {
4301 int offset_offset = java_lang_String::offset_offset_in_bytes();
4302 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4303 false, NULL, 0);
4304 const TypePtr* offset_field_type = string_type->add_offset(offset_offset);
4305 int offset_field_idx = C->get_alias_index(offset_field_type);
4306
4307 str = shenandoah_read_barrier(str);
4308
4309 return make_load(ctrl,
4310 basic_plus_adr(str, str, offset_offset),
4311 TypeInt::INT, T_INT, offset_field_idx, MemNode::unordered);
4312 } else {
4313 return intcon(0);
4314 }
4315 }
4316
4317 Node* GraphKit::load_String_length(Node* ctrl, Node* str) {
4318 if (java_lang_String::has_count_field()) {
4319 int count_offset = java_lang_String::count_offset_in_bytes();
4320 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4321 false, NULL, 0);
4322 const TypePtr* count_field_type = string_type->add_offset(count_offset);
4323 int count_field_idx = C->get_alias_index(count_field_type);
4324
4325 str = shenandoah_read_barrier(str);
4326
4327 return make_load(ctrl,
4328 basic_plus_adr(str, str, count_offset),
4329 TypeInt::INT, T_INT, count_field_idx, MemNode::unordered);
4330 } else {
4331 return load_array_length(load_String_value(ctrl, str));
4332 }
4333 }
4334
4335 Node* GraphKit::load_String_value(Node* ctrl, Node* str) {
4336 int value_offset = java_lang_String::value_offset_in_bytes();
4337 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4338 false, NULL, 0);
4339 const TypePtr* value_field_type = string_type->add_offset(value_offset);
4340 const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull,
4341 TypeAry::make(TypeInt::CHAR,TypeInt::POS),
4342 ciTypeArrayKlass::make(T_CHAR), true, 0);
4343 int value_field_idx = C->get_alias_index(value_field_type);
4344
4345 str = shenandoah_read_barrier(str);
4346
4347 Node* load = make_load(ctrl, basic_plus_adr(str, str, value_offset),
4348 value_type, T_OBJECT, value_field_idx, MemNode::unordered);
4349 // String.value field is known to be @Stable.
4350 if (UseImplicitStableValues) {
4351 load = cast_array_to_stable(load, value_type);
4352 }
4353 return load;
4354 }
4355
4356 void GraphKit::store_String_offset(Node* ctrl, Node* str, Node* value) {
4357 int offset_offset = java_lang_String::offset_offset_in_bytes();
4358 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4359 false, NULL, 0);
4360 const TypePtr* offset_field_type = string_type->add_offset(offset_offset);
4361 int offset_field_idx = C->get_alias_index(offset_field_type);
4362
4363 str = shenandoah_write_barrier(str);
4364
4365 store_to_memory(control(), basic_plus_adr(str, offset_offset),
4366 value, T_INT, offset_field_idx, MemNode::unordered);
4367 }
4368
4369 void GraphKit::store_String_value(Node* ctrl, Node* str, Node* value) {
4370 int value_offset = java_lang_String::value_offset_in_bytes();
4371 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4372 false, NULL, 0);
4373 const TypePtr* value_field_type = string_type->add_offset(value_offset);
4374
4375 str = shenandoah_write_barrier(str);
4376 value = shenandoah_read_barrier_nomem(value);
4377
4378 store_oop_to_object(control(), str, basic_plus_adr(str, value_offset), value_field_type,
4379 value, TypeAryPtr::CHARS, T_OBJECT, MemNode::unordered);
4380 }
4381
4382 void GraphKit::store_String_length(Node* ctrl, Node* str, Node* value) {
4383 int count_offset = java_lang_String::count_offset_in_bytes();
4384 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4385 false, NULL, 0);
4386 const TypePtr* count_field_type = string_type->add_offset(count_offset);
4387 int count_field_idx = C->get_alias_index(count_field_type);
4388
4389 str = shenandoah_write_barrier(str);
4390
4391 store_to_memory(control(), basic_plus_adr(str, count_offset),
4392 value, T_INT, count_field_idx, MemNode::unordered);
4393 }
4394
4395 Node* GraphKit::cast_array_to_stable(Node* ary, const TypeAryPtr* ary_type) {
4396 // Reify the property as a CastPP node in Ideal graph to comply with monotonicity
4397 // assumption of CCP analysis.
4398 return _gvn.transform(new CastPPNode(ary, ary_type->cast_to_stable(true)));
4399 }
4400
4401 Node* GraphKit::shenandoah_read_barrier(Node* obj) {
4402 return shenandoah_read_barrier_impl(obj, false, true);
4403 }
4404
4405 Node* GraphKit::shenandoah_read_barrier_nomem(Node* obj) {
4406 return shenandoah_read_barrier_impl(obj, false, false);
4407 }
4408
4409 Node* GraphKit::shenandoah_read_barrier_impl(Node* obj, bool use_ctrl, bool use_mem) {
4410
4411 if (UseShenandoahGC && ShenandoahReadBarrier) {
4412 const Type* obj_type = obj->bottom_type();
4413 if (obj_type->higher_equal(TypePtr::NULL_PTR)) {
4414 return obj;
4415 }
4416 const TypePtr* adr_type = obj_type->is_ptr()->add_offset(BrooksPointer::BYTE_OFFSET);
4417 Node* mem = use_mem ? memory(adr_type) : immutable_memory();
4418
4419 if (! ShenandoahBarrierNode::needs_barrier(&_gvn, NULL, obj, mem)) {
4420 // We know it is null, no barrier needed.
4421 return obj;
4422 }
4423
4424
4425 if (obj_type->meet(TypePtr::NULL_PTR) == obj_type->remove_speculative()) {
4426
4427 // We don't know if it's null or not. Need null-check.
4428 enum { _not_null_path = 1, _null_path, PATH_LIMIT };
4429 RegionNode* region = new RegionNode(PATH_LIMIT);
4430 Node* phi = new PhiNode(region, obj_type);
4431 Node* null_ctrl = top();
4432 Node* not_null_obj = null_check_oop(obj, &null_ctrl);
4433
4434 region->init_req(_null_path, null_ctrl);
4435 phi ->init_req(_null_path, obj);
4436
4437 Node* ctrl = use_ctrl ? control() : NULL;
4438 ShenandoahReadBarrierNode* rb = new ShenandoahReadBarrierNode(ctrl, mem, not_null_obj);
4439 Node* n = _gvn.transform(rb);
4440
4441 region->init_req(_not_null_path, control());
4442 phi ->init_req(_not_null_path, n);
4443
4444 set_control(_gvn.transform(region));
4445 record_for_igvn(region);
4446 return _gvn.transform(phi);
4447
4448 } else {
4449 // We know it is not null. Simple barrier is sufficient.
4450 Node* ctrl = use_ctrl ? control() : NULL;
4451 ShenandoahReadBarrierNode* rb = new ShenandoahReadBarrierNode(ctrl, mem, obj);
4452 Node* n = _gvn.transform(rb);
4453 record_for_igvn(n);
4454 return n;
4455 }
4456
4457 } else {
4458 return obj;
4459 }
4460 }
4461
4462 Node* GraphKit::shenandoah_write_barrier(Node* obj) {
4463
4464 if (UseShenandoahGC && ShenandoahWriteBarrier) {
4465
4466 if (! ShenandoahBarrierNode::needs_barrier(&_gvn, NULL, obj, NULL)) {
4467 return obj;
4468 }
4469 const Type* obj_type = obj->bottom_type();
4470 const TypePtr* adr_type = obj_type->is_ptr()->add_offset(BrooksPointer::BYTE_OFFSET);
4471 if (obj_type->meet(TypePtr::NULL_PTR) == obj_type->remove_speculative()) {
4472 // We don't know if it's null or not. Need null-check.
4473 enum { _not_null_path = 1, _null_path, PATH_LIMIT };
4474 RegionNode* region = new RegionNode(PATH_LIMIT);
4475 Node* phi = new PhiNode(region, obj_type);
4476 Node* memphi = PhiNode::make(region, memory(adr_type), Type::MEMORY, C->alias_type(adr_type)->adr_type());
4477
4478 Node* prev_mem = memory(adr_type);
4479 Node* null_ctrl = top();
4480 Node* not_null_obj = null_check_oop(obj, &null_ctrl);
4481
4482 region->init_req(_null_path, null_ctrl);
4483 phi ->init_req(_null_path, null());
4484 memphi->init_req(_null_path, prev_mem);
4485
4486 ShenandoahWriteBarrierNode* wb = new ShenandoahWriteBarrierNode(NULL, memory(adr_type), not_null_obj);
4487 Node* n = _gvn.transform(wb);
4488 if (n == wb) { // New barrier needs memory projection.
4489 Node* proj = _gvn.transform(new ShenandoahWBMemProjNode(n));
4490 set_memory(proj, adr_type);
4491 }
4492
4493 region->init_req(_not_null_path, control());
4494 phi ->init_req(_not_null_path, n);
4495 memphi->init_req(_not_null_path, memory(adr_type));
4496
4497 set_control(_gvn.transform(region));
4498 record_for_igvn(region);
4499 set_memory(_gvn.transform(memphi), adr_type);
4500
4501 Node* res_val = _gvn.transform(phi);
4502 // replace_in_map(obj, res_val);
4503 return res_val;
4504 } else {
4505 // We know it is not null. Simple barrier is sufficient.
4506 ShenandoahWriteBarrierNode* wb = new ShenandoahWriteBarrierNode(NULL, memory(adr_type), obj);
4507 Node* n = _gvn.transform(wb);
4508 if (n == wb) {
4509 Node* proj = _gvn.transform(new ShenandoahWBMemProjNode(wb));
4510 set_memory(proj, adr_type);
4511 }
4512 // replace_in_map(obj, n);
4513 record_for_igvn(n);
4514 return n;
4515 }
4516
4517 } else {
4518 return obj;
4519 }
4520 }
4521
4522 /**
4523 * We need barriers on acmp (and similar instructions that compare two
4524 * oops) to avoid false negatives. If it compares a from-space and a to-space
4525 * copy of an object, a regular acmp would return false, even though both are
4526 * the same. The acmp barrier compares the two objects, and when they are
4527 * *not equal* it does a read-barrier on both, and compares them again. When it
4528 * failed because of different copies of the object, we know that the object
4529 * must already have been evacuated (and therefore doesn't require a write-barrier).
4530 */
4531 void GraphKit::shenandoah_acmp_barrier(Node*& a, Node*& b) {
4532 if (UseShenandoahGC) {
4533 const Type* a_type = a->bottom_type();
4534 const Type* b_type = b->bottom_type();
4535 if (a_type->higher_equal(TypePtr::NULL_PTR) || b_type->higher_equal(TypePtr::NULL_PTR)) {
4536 // We know one arg is gonna be null. No need for barriers.
4537 return;
4538 }
4539 if (a_type->is_oopptr()->const_oop() != NULL && b_type->is_oopptr()->const_oop() != NULL ) {
4540 // We know one arg is inlined constant. No need for barriers.
4541 return;
4542 }
4543 if (a->Opcode() == Op_ShenandoahWriteBarrier && b->Opcode() == Op_ShenandoahWriteBarrier) {
4544 // We know one arg is already write-barrier'd. No need for barriers.
4545 return;
4546 }
4547 if (AllocateNode::Ideal_allocation(a, &_gvn) != NULL || AllocateNode::Ideal_allocation(b, &_gvn) != NULL) {
4548 // We know one arg is already in to-space. No need for barriers.
4549 return;
4550 }
4551
4552 enum { _equal = 1, _not_equal, PATH_LIMIT };
4553 RegionNode* region = new RegionNode(PATH_LIMIT);
4554 PhiNode* phiA = PhiNode::make(region, a);
4555 PhiNode* phiB = PhiNode::make(region, b);
4556
4557 Node* cmp = _gvn.transform(new CmpPNode(b, a));
4558 Node* tst = _gvn.transform(new BoolNode(cmp, BoolTest::eq));
4559
4560 // TODO: Use profiling data.
4561 IfNode* iff = create_and_map_if(control(), tst, PROB_FAIR, COUNT_UNKNOWN);
4562 Node* iftrue = _gvn.transform(new IfTrueNode(iff));
4563 Node* iffalse = _gvn.transform(new IfFalseNode(iff));
4564
4565 // Equal path: Use original values.
4566 region->init_req(_equal, iftrue);
4567 phiA->init_req(_equal, a);
4568 phiB->init_req(_equal, b);
4569
4570 // Unequal path: retry after read barriers.
4571 set_control(iffalse);
4572 a = shenandoah_read_barrier_impl(a, true, true);
4573 b = shenandoah_read_barrier_impl(b, true, true);
4574
4575 region->init_req(_not_equal, control());
4576 phiA->init_req(_not_equal, a);
4577 phiB->init_req(_not_equal, b);
4578
4579 set_control(_gvn.transform(region));
4580 record_for_igvn(region);
4581
4582 a = _gvn.transform(phiA);
4583 b = _gvn.transform(phiB);
4584 }
4585 }