rev 59195 : 8244594: [BACKOUT] 8244523: Shenandoah: Remove null-handling in LRB expansion
rev 59196 : 8244595: [REDO] 8244523: Shenandoah: Remove null-handling in LRB expansion
1 /*
2 * Copyright (c) 2018, 2019, Red Hat, Inc. 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 "gc/shared/barrierSet.hpp"
27 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.hpp"
29 #include "gc/shenandoah/shenandoahHeap.hpp"
30 #include "gc/shenandoah/shenandoahHeuristics.hpp"
31 #include "gc/shenandoah/shenandoahRuntime.hpp"
32 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
33 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
34 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
35 #include "opto/arraycopynode.hpp"
36 #include "opto/escape.hpp"
37 #include "opto/graphKit.hpp"
38 #include "opto/idealKit.hpp"
39 #include "opto/macro.hpp"
40 #include "opto/movenode.hpp"
41 #include "opto/narrowptrnode.hpp"
42 #include "opto/rootnode.hpp"
43 #include "opto/runtime.hpp"
44
45 ShenandoahBarrierSetC2* ShenandoahBarrierSetC2::bsc2() {
46 return reinterpret_cast<ShenandoahBarrierSetC2*>(BarrierSet::barrier_set()->barrier_set_c2());
47 }
48
49 ShenandoahBarrierSetC2State::ShenandoahBarrierSetC2State(Arena* comp_arena)
50 : _enqueue_barriers(new (comp_arena) GrowableArray<ShenandoahEnqueueBarrierNode*>(comp_arena, 8, 0, NULL)),
51 _load_reference_barriers(new (comp_arena) GrowableArray<ShenandoahLoadReferenceBarrierNode*>(comp_arena, 8, 0, NULL)) {
52 }
53
54 int ShenandoahBarrierSetC2State::enqueue_barriers_count() const {
55 return _enqueue_barriers->length();
56 }
57
58 ShenandoahEnqueueBarrierNode* ShenandoahBarrierSetC2State::enqueue_barrier(int idx) const {
59 return _enqueue_barriers->at(idx);
60 }
61
62 void ShenandoahBarrierSetC2State::add_enqueue_barrier(ShenandoahEnqueueBarrierNode * n) {
63 assert(!_enqueue_barriers->contains(n), "duplicate entry in barrier list");
64 _enqueue_barriers->append(n);
65 }
66
67 void ShenandoahBarrierSetC2State::remove_enqueue_barrier(ShenandoahEnqueueBarrierNode * n) {
68 if (_enqueue_barriers->contains(n)) {
69 _enqueue_barriers->remove(n);
70 }
71 }
72
73 int ShenandoahBarrierSetC2State::load_reference_barriers_count() const {
74 return _load_reference_barriers->length();
75 }
76
77 ShenandoahLoadReferenceBarrierNode* ShenandoahBarrierSetC2State::load_reference_barrier(int idx) const {
78 return _load_reference_barriers->at(idx);
79 }
80
81 void ShenandoahBarrierSetC2State::add_load_reference_barrier(ShenandoahLoadReferenceBarrierNode * n) {
82 assert(!_load_reference_barriers->contains(n), "duplicate entry in barrier list");
83 _load_reference_barriers->append(n);
84 }
85
86 void ShenandoahBarrierSetC2State::remove_load_reference_barrier(ShenandoahLoadReferenceBarrierNode * n) {
87 if (_load_reference_barriers->contains(n)) {
88 _load_reference_barriers->remove(n);
89 }
90 }
91
92 Node* ShenandoahBarrierSetC2::shenandoah_storeval_barrier(GraphKit* kit, Node* obj) const {
93 if (ShenandoahStoreValEnqueueBarrier) {
94 obj = shenandoah_enqueue_barrier(kit, obj);
95 }
96 return obj;
97 }
98
99 #define __ kit->
100
101 bool ShenandoahBarrierSetC2::satb_can_remove_pre_barrier(GraphKit* kit, PhaseTransform* phase, Node* adr,
102 BasicType bt, uint adr_idx) const {
103 intptr_t offset = 0;
104 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
105 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
106
107 if (offset == Type::OffsetBot) {
108 return false; // cannot unalias unless there are precise offsets
109 }
110
111 if (alloc == NULL) {
112 return false; // No allocation found
113 }
114
115 intptr_t size_in_bytes = type2aelembytes(bt);
116
117 Node* mem = __ memory(adr_idx); // start searching here...
118
119 for (int cnt = 0; cnt < 50; cnt++) {
120
121 if (mem->is_Store()) {
122
123 Node* st_adr = mem->in(MemNode::Address);
124 intptr_t st_offset = 0;
125 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
126
127 if (st_base == NULL) {
128 break; // inscrutable pointer
129 }
130
131 // Break we have found a store with same base and offset as ours so break
132 if (st_base == base && st_offset == offset) {
133 break;
134 }
135
136 if (st_offset != offset && st_offset != Type::OffsetBot) {
137 const int MAX_STORE = BytesPerLong;
138 if (st_offset >= offset + size_in_bytes ||
139 st_offset <= offset - MAX_STORE ||
140 st_offset <= offset - mem->as_Store()->memory_size()) {
141 // Success: The offsets are provably independent.
142 // (You may ask, why not just test st_offset != offset and be done?
143 // The answer is that stores of different sizes can co-exist
144 // in the same sequence of RawMem effects. We sometimes initialize
145 // a whole 'tile' of array elements with a single jint or jlong.)
146 mem = mem->in(MemNode::Memory);
147 continue; // advance through independent store memory
148 }
149 }
150
151 if (st_base != base
152 && MemNode::detect_ptr_independence(base, alloc, st_base,
153 AllocateNode::Ideal_allocation(st_base, phase),
154 phase)) {
155 // Success: The bases are provably independent.
156 mem = mem->in(MemNode::Memory);
157 continue; // advance through independent store memory
158 }
159 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
160
161 InitializeNode* st_init = mem->in(0)->as_Initialize();
162 AllocateNode* st_alloc = st_init->allocation();
163
164 // Make sure that we are looking at the same allocation site.
165 // The alloc variable is guaranteed to not be null here from earlier check.
166 if (alloc == st_alloc) {
167 // Check that the initialization is storing NULL so that no previous store
168 // has been moved up and directly write a reference
169 Node* captured_store = st_init->find_captured_store(offset,
170 type2aelembytes(T_OBJECT),
171 phase);
172 if (captured_store == NULL || captured_store == st_init->zero_memory()) {
173 return true;
174 }
175 }
176 }
177
178 // Unless there is an explicit 'continue', we must bail out here,
179 // because 'mem' is an inscrutable memory state (e.g., a call).
180 break;
181 }
182
183 return false;
184 }
185
186 #undef __
187 #define __ ideal.
188
189 void ShenandoahBarrierSetC2::satb_write_barrier_pre(GraphKit* kit,
190 bool do_load,
191 Node* obj,
192 Node* adr,
193 uint alias_idx,
194 Node* val,
195 const TypeOopPtr* val_type,
196 Node* pre_val,
197 BasicType bt) const {
198 // Some sanity checks
199 // Note: val is unused in this routine.
200
201 if (do_load) {
202 // We need to generate the load of the previous value
203 assert(obj != NULL, "must have a base");
204 assert(adr != NULL, "where are loading from?");
205 assert(pre_val == NULL, "loaded already?");
206 assert(val_type != NULL, "need a type");
207
208 if (ReduceInitialCardMarks
209 && satb_can_remove_pre_barrier(kit, &kit->gvn(), adr, bt, alias_idx)) {
210 return;
211 }
212
213 } else {
214 // In this case both val_type and alias_idx are unused.
215 assert(pre_val != NULL, "must be loaded already");
216 // Nothing to be done if pre_val is null.
217 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
218 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
219 }
220 assert(bt == T_OBJECT, "or we shouldn't be here");
221
222 IdealKit ideal(kit, true);
223
224 Node* tls = __ thread(); // ThreadLocalStorage
225
226 Node* no_base = __ top();
227 Node* zero = __ ConI(0);
228 Node* zeroX = __ ConX(0);
229
230 float likely = PROB_LIKELY(0.999);
231 float unlikely = PROB_UNLIKELY(0.999);
232
233 // Offsets into the thread
234 const int index_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset());
235 const int buffer_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
236
237 // Now the actual pointers into the thread
238 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
239 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
240
241 // Now some of the values
242 Node* marking;
243 Node* gc_state = __ AddP(no_base, tls, __ ConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset())));
244 Node* ld = __ load(__ ctrl(), gc_state, TypeInt::BYTE, T_BYTE, Compile::AliasIdxRaw);
245 marking = __ AndI(ld, __ ConI(ShenandoahHeap::MARKING));
246 assert(ShenandoahBarrierC2Support::is_gc_state_load(ld), "Should match the shape");
247
248 // if (!marking)
249 __ if_then(marking, BoolTest::ne, zero, unlikely); {
250 BasicType index_bt = TypeX_X->basic_type();
251 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 SATBMarkQueue::_index with wrong size.");
252 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
253
254 if (do_load) {
255 // load original value
256 // alias_idx correct??
257 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
258 }
259
260 // if (pre_val != NULL)
261 __ if_then(pre_val, BoolTest::ne, kit->null()); {
262 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
263
264 // is the queue for this thread full?
265 __ if_then(index, BoolTest::ne, zeroX, likely); {
266
267 // decrement the index
268 Node* next_index = kit->gvn().transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
269
270 // Now get the buffer location we will log the previous value into and store it
271 Node *log_addr = __ AddP(no_base, buffer, next_index);
272 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
273 // update the index
274 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
275
276 } __ else_(); {
277
278 // logging buffer is full, call the runtime
279 const TypeFunc *tf = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type();
280 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), "shenandoah_wb_pre", pre_val, tls);
281 } __ end_if(); // (!index)
282 } __ end_if(); // (pre_val != NULL)
283 } __ end_if(); // (!marking)
284
285 // Final sync IdealKit and GraphKit.
286 kit->final_sync(ideal);
287
288 if (ShenandoahSATBBarrier && adr != NULL) {
289 Node* c = kit->control();
290 Node* call = c->in(1)->in(1)->in(1)->in(0);
291 assert(is_shenandoah_wb_pre_call(call), "shenandoah_wb_pre call expected");
292 call->add_req(adr);
293 }
294 }
295
296 bool ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(Node* call) {
297 return call->is_CallLeaf() &&
298 call->as_CallLeaf()->entry_point() == CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry);
299 }
300
301 bool ShenandoahBarrierSetC2::is_shenandoah_lrb_call(Node* call) {
302 if (!call->is_CallLeaf()) {
303 return false;
304 }
305
306 address entry_point = call->as_CallLeaf()->entry_point();
307 return (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier)) ||
308 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow)) ||
309 (entry_point == CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_native));
310 }
311
312 bool ShenandoahBarrierSetC2::is_shenandoah_marking_if(PhaseTransform *phase, Node* n) {
313 if (n->Opcode() != Op_If) {
314 return false;
315 }
316
317 Node* bol = n->in(1);
318 assert(bol->is_Bool(), "");
319 Node* cmpx = bol->in(1);
320 if (bol->as_Bool()->_test._test == BoolTest::ne &&
321 cmpx->is_Cmp() && cmpx->in(2) == phase->intcon(0) &&
322 is_shenandoah_state_load(cmpx->in(1)->in(1)) &&
323 cmpx->in(1)->in(2)->is_Con() &&
324 cmpx->in(1)->in(2) == phase->intcon(ShenandoahHeap::MARKING)) {
325 return true;
326 }
327
328 return false;
329 }
330
331 bool ShenandoahBarrierSetC2::is_shenandoah_state_load(Node* n) {
332 if (!n->is_Load()) return false;
333 const int state_offset = in_bytes(ShenandoahThreadLocalData::gc_state_offset());
334 return n->in(2)->is_AddP() && n->in(2)->in(2)->Opcode() == Op_ThreadLocal
335 && n->in(2)->in(3)->is_Con()
336 && n->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == state_offset;
337 }
338
339 void ShenandoahBarrierSetC2::shenandoah_write_barrier_pre(GraphKit* kit,
340 bool do_load,
341 Node* obj,
342 Node* adr,
343 uint alias_idx,
344 Node* val,
345 const TypeOopPtr* val_type,
346 Node* pre_val,
347 BasicType bt) const {
348 if (ShenandoahSATBBarrier) {
349 IdealKit ideal(kit);
350 kit->sync_kit(ideal);
351
352 satb_write_barrier_pre(kit, do_load, obj, adr, alias_idx, val, val_type, pre_val, bt);
353
354 ideal.sync_kit(kit);
355 kit->final_sync(ideal);
356 }
357 }
358
359 Node* ShenandoahBarrierSetC2::shenandoah_enqueue_barrier(GraphKit* kit, Node* pre_val) const {
360 return kit->gvn().transform(new ShenandoahEnqueueBarrierNode(pre_val));
361 }
362
363 // Helper that guards and inserts a pre-barrier.
364 void ShenandoahBarrierSetC2::insert_pre_barrier(GraphKit* kit, Node* base_oop, Node* offset,
365 Node* pre_val, bool need_mem_bar) const {
366 // We could be accessing the referent field of a reference object. If so, when G1
367 // is enabled, we need to log the value in the referent field in an SATB buffer.
368 // This routine performs some compile time filters and generates suitable
369 // runtime filters that guard the pre-barrier code.
370 // Also add memory barrier for non volatile load from the referent field
371 // to prevent commoning of loads across safepoint.
372
373 // Some compile time checks.
374
375 // If offset is a constant, is it java_lang_ref_Reference::_reference_offset?
376 const TypeX* otype = offset->find_intptr_t_type();
377 if (otype != NULL && otype->is_con() &&
378 otype->get_con() != java_lang_ref_Reference::referent_offset) {
379 // Constant offset but not the reference_offset so just return
380 return;
381 }
382
383 // We only need to generate the runtime guards for instances.
384 const TypeOopPtr* btype = base_oop->bottom_type()->isa_oopptr();
385 if (btype != NULL) {
386 if (btype->isa_aryptr()) {
387 // Array type so nothing to do
388 return;
389 }
390
391 const TypeInstPtr* itype = btype->isa_instptr();
392 if (itype != NULL) {
393 // Can the klass of base_oop be statically determined to be
394 // _not_ a sub-class of Reference and _not_ Object?
395 ciKlass* klass = itype->klass();
396 if ( klass->is_loaded() &&
397 !klass->is_subtype_of(kit->env()->Reference_klass()) &&
398 !kit->env()->Object_klass()->is_subtype_of(klass)) {
399 return;
400 }
401 }
402 }
403
404 // The compile time filters did not reject base_oop/offset so
405 // we need to generate the following runtime filters
406 //
407 // if (offset == java_lang_ref_Reference::_reference_offset) {
408 // if (instance_of(base, java.lang.ref.Reference)) {
409 // pre_barrier(_, pre_val, ...);
410 // }
411 // }
412
413 float likely = PROB_LIKELY( 0.999);
414 float unlikely = PROB_UNLIKELY(0.999);
415
416 IdealKit ideal(kit);
417
418 Node* referent_off = __ ConX(java_lang_ref_Reference::referent_offset);
419
420 __ if_then(offset, BoolTest::eq, referent_off, unlikely); {
421 // Update graphKit memory and control from IdealKit.
422 kit->sync_kit(ideal);
423
424 Node* ref_klass_con = kit->makecon(TypeKlassPtr::make(kit->env()->Reference_klass()));
425 Node* is_instof = kit->gen_instanceof(base_oop, ref_klass_con);
426
427 // Update IdealKit memory and control from graphKit.
428 __ sync_kit(kit);
429
430 Node* one = __ ConI(1);
431 // is_instof == 0 if base_oop == NULL
432 __ if_then(is_instof, BoolTest::eq, one, unlikely); {
433
434 // Update graphKit from IdeakKit.
435 kit->sync_kit(ideal);
436
437 // Use the pre-barrier to record the value in the referent field
438 satb_write_barrier_pre(kit, false /* do_load */,
439 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
440 pre_val /* pre_val */,
441 T_OBJECT);
442 if (need_mem_bar) {
443 // Add memory barrier to prevent commoning reads from this field
444 // across safepoint since GC can change its value.
445 kit->insert_mem_bar(Op_MemBarCPUOrder);
446 }
447 // Update IdealKit from graphKit.
448 __ sync_kit(kit);
449
450 } __ end_if(); // _ref_type != ref_none
451 } __ end_if(); // offset == referent_offset
452
453 // Final sync IdealKit and GraphKit.
454 kit->final_sync(ideal);
455 }
456
457 #undef __
458
459 const TypeFunc* ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type() {
460 const Type **fields = TypeTuple::fields(2);
461 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
462 fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread
463 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
464
465 // create result type (range)
466 fields = TypeTuple::fields(0);
467 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
468
469 return TypeFunc::make(domain, range);
470 }
471
472 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
473 const Type **fields = TypeTuple::fields(1);
474 fields[TypeFunc::Parms+0] = TypeOopPtr::NOTNULL; // src oop
475 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
476
477 // create result type (range)
478 fields = TypeTuple::fields(0);
479 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
480
481 return TypeFunc::make(domain, range);
482 }
483
484 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type() {
485 const Type **fields = TypeTuple::fields(2);
486 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
487 fields[TypeFunc::Parms+1] = TypeRawPtr::BOTTOM; // original load address
488
489 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
490
491 // create result type (range)
492 fields = TypeTuple::fields(1);
493 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL;
494 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
495
496 return TypeFunc::make(domain, range);
497 }
498
499 Node* ShenandoahBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
500 DecoratorSet decorators = access.decorators();
501
502 const TypePtr* adr_type = access.addr().type();
503 Node* adr = access.addr().node();
504
505 bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
506 bool on_heap = (decorators & IN_HEAP) != 0;
507
508 if (!access.is_oop() || (!on_heap && !anonymous)) {
509 return BarrierSetC2::store_at_resolved(access, val);
510 }
511
512 if (access.is_parse_access()) {
513 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
514 GraphKit* kit = parse_access.kit();
515
516 uint adr_idx = kit->C->get_alias_index(adr_type);
517 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
518 Node* value = val.node();
519 value = shenandoah_storeval_barrier(kit, value);
520 val.set_node(value);
521 shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
522 static_cast<const TypeOopPtr*>(val.type()), NULL /* pre_val */, access.type());
523 } else {
524 assert(access.is_opt_access(), "only for optimization passes");
525 assert(((decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0 || !ShenandoahSATBBarrier) && (decorators & C2_ARRAY_COPY) != 0, "unexpected caller of this code");
526 C2OptAccess& opt_access = static_cast<C2OptAccess&>(access);
527 PhaseGVN& gvn = opt_access.gvn();
528 MergeMemNode* mm = opt_access.mem();
529
530 if (ShenandoahStoreValEnqueueBarrier) {
531 Node* enqueue = gvn.transform(new ShenandoahEnqueueBarrierNode(val.node()));
532 val.set_node(enqueue);
533 }
534 }
535 return BarrierSetC2::store_at_resolved(access, val);
536 }
537
538 Node* ShenandoahBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
539 // 1: non-reference load, no additional barrier is needed
540 if (!access.is_oop()) {
541 return BarrierSetC2::load_at_resolved(access, val_type);;
542 }
543
544 Node* load = BarrierSetC2::load_at_resolved(access, val_type);
545 DecoratorSet decorators = access.decorators();
546 BasicType type = access.type();
547
548 // 2: apply LRB if needed
549 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
550 load = new ShenandoahLoadReferenceBarrierNode(NULL,
551 load,
552 ShenandoahBarrierSet::use_load_reference_barrier_native(decorators, type));
553 if (access.is_parse_access()) {
554 load = static_cast<C2ParseAccess &>(access).kit()->gvn().transform(load);
555 } else {
556 load = static_cast<C2OptAccess &>(access).gvn().transform(load);
557 }
558 }
559
560 // 3: apply keep-alive barrier if needed
561 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
562 Node* top = Compile::current()->top();
563 Node* adr = access.addr().node();
564 Node* offset = adr->is_AddP() ? adr->in(AddPNode::Offset) : top;
565 Node* obj = access.base();
566
567 bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
568 bool on_weak_ref = (decorators & (ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF)) != 0;
569 bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0;
570
571 // If we are reading the value of the referent field of a Reference
572 // object (either by using Unsafe directly or through reflection)
573 // then, if SATB is enabled, we need to record the referent in an
574 // SATB log buffer using the pre-barrier mechanism.
575 // Also we need to add memory barrier to prevent commoning reads
576 // from this field across safepoint since GC can change its value.
577 if (!on_weak_ref || (unknown && (offset == top || obj == top)) || !keep_alive) {
578 return load;
579 }
580
581 assert(access.is_parse_access(), "entry not supported at optimization time");
582 C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
583 GraphKit* kit = parse_access.kit();
584 bool mismatched = (decorators & C2_MISMATCHED) != 0;
585 bool is_unordered = (decorators & MO_UNORDERED) != 0;
586 bool in_native = (decorators & IN_NATIVE) != 0;
587 bool need_cpu_mem_bar = !is_unordered || mismatched || in_native;
588
589 if (on_weak_ref) {
590 // Use the pre-barrier to record the value in the referent field
591 satb_write_barrier_pre(kit, false /* do_load */,
592 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
593 load /* pre_val */, T_OBJECT);
594 // Add memory barrier to prevent commoning reads from this field
595 // across safepoint since GC can change its value.
596 kit->insert_mem_bar(Op_MemBarCPUOrder);
597 } else if (unknown) {
598 // We do not require a mem bar inside pre_barrier if need_mem_bar
599 // is set: the barriers would be emitted by us.
600 insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
601 }
602 }
603
604 return load;
605 }
606
607 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
608 Node* new_val, const Type* value_type) const {
609 GraphKit* kit = access.kit();
610 if (access.is_oop()) {
611 new_val = shenandoah_storeval_barrier(kit, new_val);
612 shenandoah_write_barrier_pre(kit, false /* do_load */,
613 NULL, NULL, max_juint, NULL, NULL,
614 expected_val /* pre_val */, T_OBJECT);
615
616 MemNode::MemOrd mo = access.mem_node_mo();
617 Node* mem = access.memory();
618 Node* adr = access.addr().node();
619 const TypePtr* adr_type = access.addr().type();
620 Node* load_store = NULL;
621
622 #ifdef _LP64
623 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
624 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
625 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
626 if (ShenandoahCASBarrier) {
627 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
628 } else {
629 load_store = kit->gvn().transform(new CompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
630 }
631 } else
632 #endif
633 {
634 if (ShenandoahCASBarrier) {
635 load_store = kit->gvn().transform(new ShenandoahCompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
636 } else {
637 load_store = kit->gvn().transform(new CompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
638 }
639 }
640
641 access.set_raw_access(load_store);
642 pin_atomic_op(access);
643
644 #ifdef _LP64
645 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
646 load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
647 }
648 #endif
649 load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, load_store, false));
650 return load_store;
651 }
652 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
653 }
654
655 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
656 Node* new_val, const Type* value_type) const {
657 GraphKit* kit = access.kit();
658 if (access.is_oop()) {
659 new_val = shenandoah_storeval_barrier(kit, new_val);
660 shenandoah_write_barrier_pre(kit, false /* do_load */,
661 NULL, NULL, max_juint, NULL, NULL,
662 expected_val /* pre_val */, T_OBJECT);
663 DecoratorSet decorators = access.decorators();
664 MemNode::MemOrd mo = access.mem_node_mo();
665 Node* mem = access.memory();
666 bool is_weak_cas = (decorators & C2_WEAK_CMPXCHG) != 0;
667 Node* load_store = NULL;
668 Node* adr = access.addr().node();
669 #ifdef _LP64
670 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
671 Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
672 Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
673 if (ShenandoahCASBarrier) {
674 if (is_weak_cas) {
675 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
676 } else {
677 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
678 }
679 } else {
680 if (is_weak_cas) {
681 load_store = kit->gvn().transform(new WeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
682 } else {
683 load_store = kit->gvn().transform(new CompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
684 }
685 }
686 } else
687 #endif
688 {
689 if (ShenandoahCASBarrier) {
690 if (is_weak_cas) {
691 load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
692 } else {
693 load_store = kit->gvn().transform(new ShenandoahCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
694 }
695 } else {
696 if (is_weak_cas) {
697 load_store = kit->gvn().transform(new WeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
698 } else {
699 load_store = kit->gvn().transform(new CompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
700 }
701 }
702 }
703 access.set_raw_access(load_store);
704 pin_atomic_op(access);
705 return load_store;
706 }
707 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
708 }
709
710 Node* ShenandoahBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* val, const Type* value_type) const {
711 GraphKit* kit = access.kit();
712 if (access.is_oop()) {
713 val = shenandoah_storeval_barrier(kit, val);
714 }
715 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
716 if (access.is_oop()) {
717 result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, result, false));
718 shenandoah_write_barrier_pre(kit, false /* do_load */,
719 NULL, NULL, max_juint, NULL, NULL,
720 result /* pre_val */, T_OBJECT);
721 }
722 return result;
723 }
724
725 // Support for GC barriers emitted during parsing
726 bool ShenandoahBarrierSetC2::is_gc_barrier_node(Node* node) const {
727 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) return true;
728 if (node->Opcode() != Op_CallLeaf && node->Opcode() != Op_CallLeafNoFP) {
729 return false;
730 }
731 CallLeafNode *call = node->as_CallLeaf();
732 if (call->_name == NULL) {
733 return false;
734 }
735
736 return strcmp(call->_name, "shenandoah_clone_barrier") == 0 ||
737 strcmp(call->_name, "shenandoah_cas_obj") == 0 ||
738 strcmp(call->_name, "shenandoah_wb_pre") == 0;
739 }
740
741 Node* ShenandoahBarrierSetC2::step_over_gc_barrier(Node* c) const {
742 if (c == NULL) {
743 return c;
744 }
745 if (c->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
746 return c->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
747 }
748 if (c->Opcode() == Op_ShenandoahEnqueueBarrier) {
749 c = c->in(1);
750 }
751 return c;
752 }
753
754 bool ShenandoahBarrierSetC2::expand_barriers(Compile* C, PhaseIterGVN& igvn) const {
755 return !ShenandoahBarrierC2Support::expand(C, igvn);
756 }
757
758 bool ShenandoahBarrierSetC2::optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const {
759 if (mode == LoopOptsShenandoahExpand) {
760 assert(UseShenandoahGC, "only for shenandoah");
761 ShenandoahBarrierC2Support::pin_and_expand(phase);
762 return true;
763 } else if (mode == LoopOptsShenandoahPostExpand) {
764 assert(UseShenandoahGC, "only for shenandoah");
765 visited.clear();
766 ShenandoahBarrierC2Support::optimize_after_expansion(visited, nstack, worklist, phase);
767 return true;
768 }
769 return false;
770 }
771
772 bool ShenandoahBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const {
773 bool is_oop = is_reference_type(type);
774 if (!is_oop) {
775 return false;
776 }
777 if (ShenandoahSATBBarrier && tightly_coupled_alloc) {
778 if (phase == Optimization) {
779 return false;
780 }
781 return !is_clone;
782 }
783 if (phase == Optimization) {
784 return !ShenandoahStoreValEnqueueBarrier;
785 }
786 return true;
787 }
788
789 bool ShenandoahBarrierSetC2::clone_needs_barrier(Node* src, PhaseGVN& gvn) {
790 const TypeOopPtr* src_type = gvn.type(src)->is_oopptr();
791 if (src_type->isa_instptr() != NULL) {
792 ciInstanceKlass* ik = src_type->klass()->as_instance_klass();
793 if ((src_type->klass_is_exact() || (!ik->is_interface() && !ik->has_subklass())) && !ik->has_injected_fields()) {
794 if (ik->has_object_fields()) {
795 return true;
796 } else {
797 if (!src_type->klass_is_exact()) {
798 Compile::current()->dependencies()->assert_leaf_type(ik);
799 }
800 }
801 } else {
802 return true;
803 }
804 } else if (src_type->isa_aryptr()) {
805 BasicType src_elem = src_type->klass()->as_array_klass()->element_type()->basic_type();
806 if (is_reference_type(src_elem)) {
807 return true;
808 }
809 } else {
810 return true;
811 }
812 return false;
813 }
814
815 void ShenandoahBarrierSetC2::clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const {
816 Node* ctrl = ac->in(TypeFunc::Control);
817 Node* mem = ac->in(TypeFunc::Memory);
818 Node* src_base = ac->in(ArrayCopyNode::Src);
819 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
820 Node* dest_base = ac->in(ArrayCopyNode::Dest);
821 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
822 Node* length = ac->in(ArrayCopyNode::Length);
823
824 Node* src = phase->basic_plus_adr(src_base, src_offset);
825 Node* dest = phase->basic_plus_adr(dest_base, dest_offset);
826
827 if (ShenandoahCloneBarrier && clone_needs_barrier(src, phase->igvn())) {
828 // Check if heap is has forwarded objects. If it does, we need to call into the special
829 // routine that would fix up source references before we can continue.
830
831 enum { _heap_stable = 1, _heap_unstable, PATH_LIMIT };
832 Node* region = new RegionNode(PATH_LIMIT);
833 Node* mem_phi = new PhiNode(region, Type::MEMORY, TypeRawPtr::BOTTOM);
834
835 Node* thread = phase->transform_later(new ThreadLocalNode());
836 Node* offset = phase->igvn().MakeConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
837 Node* gc_state_addr = phase->transform_later(new AddPNode(phase->C->top(), thread, offset));
838
839 uint gc_state_idx = Compile::AliasIdxRaw;
840 const TypePtr* gc_state_adr_type = NULL; // debug-mode-only argument
841 debug_only(gc_state_adr_type = phase->C->get_adr_type(gc_state_idx));
842
843 Node* gc_state = phase->transform_later(new LoadBNode(ctrl, mem, gc_state_addr, gc_state_adr_type, TypeInt::BYTE, MemNode::unordered));
844 int flags = ShenandoahHeap::HAS_FORWARDED;
845 if (ShenandoahStoreValEnqueueBarrier) {
846 flags |= ShenandoahHeap::MARKING;
847 }
848 Node* stable_and = phase->transform_later(new AndINode(gc_state, phase->igvn().intcon(flags)));
849 Node* stable_cmp = phase->transform_later(new CmpINode(stable_and, phase->igvn().zerocon(T_INT)));
850 Node* stable_test = phase->transform_later(new BoolNode(stable_cmp, BoolTest::ne));
851
852 IfNode* stable_iff = phase->transform_later(new IfNode(ctrl, stable_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN))->as_If();
853 Node* stable_ctrl = phase->transform_later(new IfFalseNode(stable_iff));
854 Node* unstable_ctrl = phase->transform_later(new IfTrueNode(stable_iff));
855
856 // Heap is stable, no need to do anything additional
857 region->init_req(_heap_stable, stable_ctrl);
858 mem_phi->init_req(_heap_stable, mem);
859
860 // Heap is unstable, call into clone barrier stub
861 Node* call = phase->make_leaf_call(unstable_ctrl, mem,
862 ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type(),
863 CAST_FROM_FN_PTR(address, ShenandoahRuntime::shenandoah_clone_barrier),
864 "shenandoah_clone",
865 TypeRawPtr::BOTTOM,
866 src_base);
867 call = phase->transform_later(call);
868
869 ctrl = phase->transform_later(new ProjNode(call, TypeFunc::Control));
870 mem = phase->transform_later(new ProjNode(call, TypeFunc::Memory));
871 region->init_req(_heap_unstable, ctrl);
872 mem_phi->init_req(_heap_unstable, mem);
873
874 // Wire up the actual arraycopy stub now
875 ctrl = phase->transform_later(region);
876 mem = phase->transform_later(mem_phi);
877
878 const char* name = "arraycopy";
879 call = phase->make_leaf_call(ctrl, mem,
880 OptoRuntime::fast_arraycopy_Type(),
881 phase->basictype2arraycopy(T_LONG, NULL, NULL, true, name, true),
882 name, TypeRawPtr::BOTTOM,
883 src, dest, length
884 LP64_ONLY(COMMA phase->top()));
885 call = phase->transform_later(call);
886
887 // Hook up the whole thing into the graph
888 phase->igvn().replace_node(ac, call);
889 } else {
890 BarrierSetC2::clone_at_expansion(phase, ac);
891 }
892 }
893
894
895 // Support for macro expanded GC barriers
896 void ShenandoahBarrierSetC2::register_potential_barrier_node(Node* node) const {
897 if (node->Opcode() == Op_ShenandoahEnqueueBarrier) {
898 state()->add_enqueue_barrier((ShenandoahEnqueueBarrierNode*) node);
899 }
900 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
901 state()->add_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
902 }
903 }
904
905 void ShenandoahBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
906 if (node->Opcode() == Op_ShenandoahEnqueueBarrier) {
907 state()->remove_enqueue_barrier((ShenandoahEnqueueBarrierNode*) node);
908 }
909 if (node->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
910 state()->remove_load_reference_barrier((ShenandoahLoadReferenceBarrierNode*) node);
911 }
912 }
913
914 void ShenandoahBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* n) const {
915 if (is_shenandoah_wb_pre_call(n)) {
916 shenandoah_eliminate_wb_pre(n, ¯o->igvn());
917 }
918 }
919
920 void ShenandoahBarrierSetC2::shenandoah_eliminate_wb_pre(Node* call, PhaseIterGVN* igvn) const {
921 assert(UseShenandoahGC && is_shenandoah_wb_pre_call(call), "");
922 Node* c = call->as_Call()->proj_out(TypeFunc::Control);
923 c = c->unique_ctrl_out();
924 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
925 c = c->unique_ctrl_out();
926 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
927 Node* iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
928 assert(iff->is_If(), "expect test");
929 if (!is_shenandoah_marking_if(igvn, iff)) {
930 c = c->unique_ctrl_out();
931 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
932 iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
933 assert(is_shenandoah_marking_if(igvn, iff), "expect marking test");
934 }
935 Node* cmpx = iff->in(1)->in(1);
936 igvn->replace_node(cmpx, igvn->makecon(TypeInt::CC_EQ));
937 igvn->rehash_node_delayed(call);
938 call->del_req(call->req()-1);
939 }
940
941 void ShenandoahBarrierSetC2::enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {
942 if (node->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(node)) {
943 igvn->add_users_to_worklist(node);
944 }
945 }
946
947 void ShenandoahBarrierSetC2::eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {
948 for (uint i = 0; i < useful.size(); i++) {
949 Node* n = useful.at(i);
950 if (n->Opcode() == Op_AddP && ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(n)) {
951 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
952 C->record_for_igvn(n->fast_out(i));
953 }
954 }
955 }
956 for (int i = state()->enqueue_barriers_count() - 1; i >= 0; i--) {
957 ShenandoahEnqueueBarrierNode* n = state()->enqueue_barrier(i);
958 if (!useful.member(n)) {
959 state()->remove_enqueue_barrier(n);
960 }
961 }
962 for (int i = state()->load_reference_barriers_count() - 1; i >= 0; i--) {
963 ShenandoahLoadReferenceBarrierNode* n = state()->load_reference_barrier(i);
964 if (!useful.member(n)) {
965 state()->remove_load_reference_barrier(n);
966 }
967 }
968 }
969
970 void* ShenandoahBarrierSetC2::create_barrier_state(Arena* comp_arena) const {
971 return new(comp_arena) ShenandoahBarrierSetC2State(comp_arena);
972 }
973
974 ShenandoahBarrierSetC2State* ShenandoahBarrierSetC2::state() const {
975 return reinterpret_cast<ShenandoahBarrierSetC2State*>(Compile::current()->barrier_set_state());
976 }
977
978 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
979 // expanded later, then now is the time to do so.
980 bool ShenandoahBarrierSetC2::expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
981
982 #ifdef ASSERT
983 void ShenandoahBarrierSetC2::verify_gc_barriers(Compile* compile, CompilePhase phase) const {
984 if (ShenandoahVerifyOptoBarriers && phase == BarrierSetC2::BeforeMacroExpand) {
985 ShenandoahBarrierC2Support::verify(Compile::current()->root());
986 } else if (phase == BarrierSetC2::BeforeCodeGen) {
987 // Verify G1 pre-barriers
988 const int marking_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset());
989
990 ResourceArea *area = Thread::current()->resource_area();
991 Unique_Node_List visited(area);
992 Node_List worklist(area);
993 // We're going to walk control flow backwards starting from the Root
994 worklist.push(compile->root());
995 while (worklist.size() > 0) {
996 Node *x = worklist.pop();
997 if (x == NULL || x == compile->top()) continue;
998 if (visited.member(x)) {
999 continue;
1000 } else {
1001 visited.push(x);
1002 }
1003
1004 if (x->is_Region()) {
1005 for (uint i = 1; i < x->req(); i++) {
1006 worklist.push(x->in(i));
1007 }
1008 } else {
1009 worklist.push(x->in(0));
1010 // We are looking for the pattern:
1011 // /->ThreadLocal
1012 // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
1013 // \->ConI(0)
1014 // We want to verify that the If and the LoadB have the same control
1015 // See GraphKit::g1_write_barrier_pre()
1016 if (x->is_If()) {
1017 IfNode *iff = x->as_If();
1018 if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
1019 CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
1020 if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
1021 && cmp->in(1)->is_Load()) {
1022 LoadNode *load = cmp->in(1)->as_Load();
1023 if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
1024 && load->in(2)->in(3)->is_Con()
1025 && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
1026
1027 Node *if_ctrl = iff->in(0);
1028 Node *load_ctrl = load->in(0);
1029
1030 if (if_ctrl != load_ctrl) {
1031 // Skip possible CProj->NeverBranch in infinite loops
1032 if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
1033 && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
1034 if_ctrl = if_ctrl->in(0)->in(0);
1035 }
1036 }
1037 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
1038 }
1039 }
1040 }
1041 }
1042 }
1043 }
1044 }
1045 }
1046 #endif
1047
1048 Node* ShenandoahBarrierSetC2::ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const {
1049 if (is_shenandoah_wb_pre_call(n)) {
1050 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1051 if (n->req() > cnt) {
1052 Node* addp = n->in(cnt);
1053 if (has_only_shenandoah_wb_pre_uses(addp)) {
1054 n->del_req(cnt);
1055 if (can_reshape) {
1056 phase->is_IterGVN()->_worklist.push(addp);
1057 }
1058 return n;
1059 }
1060 }
1061 }
1062 if (n->Opcode() == Op_CmpP) {
1063 Node* in1 = n->in(1);
1064 Node* in2 = n->in(2);
1065 if (in1->bottom_type() == TypePtr::NULL_PTR) {
1066 in2 = step_over_gc_barrier(in2);
1067 }
1068 if (in2->bottom_type() == TypePtr::NULL_PTR) {
1069 in1 = step_over_gc_barrier(in1);
1070 }
1071 PhaseIterGVN* igvn = phase->is_IterGVN();
1072 if (in1 != n->in(1)) {
1073 if (igvn != NULL) {
1074 n->set_req_X(1, in1, igvn);
1075 } else {
1076 n->set_req(1, in1);
1077 }
1078 assert(in2 == n->in(2), "only one change");
1079 return n;
1080 }
1081 if (in2 != n->in(2)) {
1082 if (igvn != NULL) {
1083 n->set_req_X(2, in2, igvn);
1084 } else {
1085 n->set_req(2, in2);
1086 }
1087 return n;
1088 }
1089 } else if (can_reshape &&
1090 n->Opcode() == Op_If &&
1091 ShenandoahBarrierC2Support::is_heap_stable_test(n) &&
1092 n->in(0) != NULL) {
1093 Node* dom = n->in(0);
1094 Node* prev_dom = n;
1095 int op = n->Opcode();
1096 int dist = 16;
1097 // Search up the dominator tree for another heap stable test
1098 while (dom->Opcode() != op || // Not same opcode?
1099 !ShenandoahBarrierC2Support::is_heap_stable_test(dom) || // Not same input 1?
1100 prev_dom->in(0) != dom) { // One path of test does not dominate?
1101 if (dist < 0) return NULL;
1102
1103 dist--;
1104 prev_dom = dom;
1105 dom = IfNode::up_one_dom(dom);
1106 if (!dom) return NULL;
1107 }
1108
1109 // Check that we did not follow a loop back to ourselves
1110 if (n == dom) {
1111 return NULL;
1112 }
1113
1114 return n->as_If()->dominated_by(prev_dom, phase->is_IterGVN());
1115 }
1116
1117 return NULL;
1118 }
1119
1120 bool ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(Node* n) {
1121 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1122 Node* u = n->fast_out(i);
1123 if (!is_shenandoah_wb_pre_call(u)) {
1124 return false;
1125 }
1126 }
1127 return n->outcnt() > 0;
1128 }
1129
1130 bool ShenandoahBarrierSetC2::final_graph_reshaping(Compile* compile, Node* n, uint opcode) const {
1131 switch (opcode) {
1132 case Op_CallLeaf:
1133 case Op_CallLeafNoFP: {
1134 assert (n->is_Call(), "");
1135 CallNode *call = n->as_Call();
1136 if (ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(call)) {
1137 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
1138 if (call->req() > cnt) {
1139 assert(call->req() == cnt + 1, "only one extra input");
1140 Node *addp = call->in(cnt);
1141 assert(!ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(addp), "useless address computation?");
1142 call->del_req(cnt);
1143 }
1144 }
1145 return false;
1146 }
1147 case Op_ShenandoahCompareAndSwapP:
1148 case Op_ShenandoahCompareAndSwapN:
1149 case Op_ShenandoahWeakCompareAndSwapN:
1150 case Op_ShenandoahWeakCompareAndSwapP:
1151 case Op_ShenandoahCompareAndExchangeP:
1152 case Op_ShenandoahCompareAndExchangeN:
1153 #ifdef ASSERT
1154 if( VerifyOptoOopOffsets ) {
1155 MemNode* mem = n->as_Mem();
1156 // Check to see if address types have grounded out somehow.
1157 const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
1158 ciInstanceKlass *k = tp->klass()->as_instance_klass();
1159 bool oop_offset_is_sane = k->contains_field_offset(tp->offset());
1160 assert( !tp || oop_offset_is_sane, "" );
1161 }
1162 #endif
1163 return true;
1164 case Op_ShenandoahLoadReferenceBarrier:
1165 assert(false, "should have been expanded already");
1166 return true;
1167 default:
1168 return false;
1169 }
1170 }
1171
1172 bool ShenandoahBarrierSetC2::escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const {
1173 switch (opcode) {
1174 case Op_ShenandoahCompareAndExchangeP:
1175 case Op_ShenandoahCompareAndExchangeN:
1176 conn_graph->add_objload_to_connection_graph(n, delayed_worklist);
1177 // fallthrough
1178 case Op_ShenandoahWeakCompareAndSwapP:
1179 case Op_ShenandoahWeakCompareAndSwapN:
1180 case Op_ShenandoahCompareAndSwapP:
1181 case Op_ShenandoahCompareAndSwapN:
1182 conn_graph->add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
1183 return true;
1184 case Op_StoreP: {
1185 Node* adr = n->in(MemNode::Address);
1186 const Type* adr_type = gvn->type(adr);
1187 // Pointer stores in G1 barriers looks like unsafe access.
1188 // Ignore such stores to be able scalar replace non-escaping
1189 // allocations.
1190 if (adr_type->isa_rawptr() && adr->is_AddP()) {
1191 Node* base = conn_graph->get_addp_base(adr);
1192 if (base->Opcode() == Op_LoadP &&
1193 base->in(MemNode::Address)->is_AddP()) {
1194 adr = base->in(MemNode::Address);
1195 Node* tls = conn_graph->get_addp_base(adr);
1196 if (tls->Opcode() == Op_ThreadLocal) {
1197 int offs = (int) gvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
1198 const int buf_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
1199 if (offs == buf_offset) {
1200 return true; // Pre barrier previous oop value store.
1201 }
1202 }
1203 }
1204 }
1205 return false;
1206 }
1207 case Op_ShenandoahEnqueueBarrier:
1208 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), delayed_worklist);
1209 break;
1210 case Op_ShenandoahLoadReferenceBarrier:
1211 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), delayed_worklist);
1212 return true;
1213 default:
1214 // Nothing
1215 break;
1216 }
1217 return false;
1218 }
1219
1220 bool ShenandoahBarrierSetC2::escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const {
1221 switch (opcode) {
1222 case Op_ShenandoahCompareAndExchangeP:
1223 case Op_ShenandoahCompareAndExchangeN: {
1224 Node *adr = n->in(MemNode::Address);
1225 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
1226 // fallthrough
1227 }
1228 case Op_ShenandoahCompareAndSwapP:
1229 case Op_ShenandoahCompareAndSwapN:
1230 case Op_ShenandoahWeakCompareAndSwapP:
1231 case Op_ShenandoahWeakCompareAndSwapN:
1232 return conn_graph->add_final_edges_unsafe_access(n, opcode);
1233 case Op_ShenandoahEnqueueBarrier:
1234 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), NULL);
1235 return true;
1236 case Op_ShenandoahLoadReferenceBarrier:
1237 conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), NULL);
1238 return true;
1239 default:
1240 // Nothing
1241 break;
1242 }
1243 return false;
1244 }
1245
1246 bool ShenandoahBarrierSetC2::escape_has_out_with_unsafe_object(Node* n) const {
1247 return n->has_out_with(Op_ShenandoahCompareAndExchangeP) || n->has_out_with(Op_ShenandoahCompareAndExchangeN) ||
1248 n->has_out_with(Op_ShenandoahCompareAndSwapP, Op_ShenandoahCompareAndSwapN, Op_ShenandoahWeakCompareAndSwapP, Op_ShenandoahWeakCompareAndSwapN);
1249
1250 }
1251
1252 bool ShenandoahBarrierSetC2::matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const {
1253 switch (opcode) {
1254 case Op_ShenandoahCompareAndExchangeP:
1255 case Op_ShenandoahCompareAndExchangeN:
1256 case Op_ShenandoahWeakCompareAndSwapP:
1257 case Op_ShenandoahWeakCompareAndSwapN:
1258 case Op_ShenandoahCompareAndSwapP:
1259 case Op_ShenandoahCompareAndSwapN: { // Convert trinary to binary-tree
1260 Node* newval = n->in(MemNode::ValueIn);
1261 Node* oldval = n->in(LoadStoreConditionalNode::ExpectedIn);
1262 Node* pair = new BinaryNode(oldval, newval);
1263 n->set_req(MemNode::ValueIn,pair);
1264 n->del_req(LoadStoreConditionalNode::ExpectedIn);
1265 return true;
1266 }
1267 default:
1268 break;
1269 }
1270 return false;
1271 }
1272
1273 bool ShenandoahBarrierSetC2::matcher_is_store_load_barrier(Node* x, uint xop) const {
1274 return xop == Op_ShenandoahCompareAndExchangeP ||
1275 xop == Op_ShenandoahCompareAndExchangeN ||
1276 xop == Op_ShenandoahWeakCompareAndSwapP ||
1277 xop == Op_ShenandoahWeakCompareAndSwapN ||
1278 xop == Op_ShenandoahCompareAndSwapN ||
1279 xop == Op_ShenandoahCompareAndSwapP;
1280 }
--- EOF ---