1 /*
2 * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "gc/shared/barrierSet.hpp"
26 #include "gc/shenandoah/shenandoahHeap.hpp"
27 #include "gc/shenandoah/shenandoahHeuristics.hpp"
28 #include "gc/shenandoah/shenandoahRuntime.hpp"
29 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
30 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
31 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
32 #include "opto/graphKit.hpp"
33 #include "opto/idealKit.hpp"
34 #include "opto/macro.hpp"
35
36 ShenandoahBarrierSetC2* ShenandoahBarrierSetC2::bsc2() {
37 return reinterpret_cast<ShenandoahBarrierSetC2*>(BarrierSet::barrier_set()->barrier_set_c2());
38 }
39
40 ShenandoahBarrierSetC2State::ShenandoahBarrierSetC2State(Arena* comp_arena)
41 : _shenandoah_barriers(new (comp_arena) GrowableArray<ShenandoahWriteBarrierNode*>(comp_arena, 8, 0, NULL)) {
42 }
43
44 int ShenandoahBarrierSetC2State::shenandoah_barriers_count() const {
45 return _shenandoah_barriers->length();
46 }
47
48 ShenandoahWriteBarrierNode* ShenandoahBarrierSetC2State::shenandoah_barrier(int idx) const {
49 return _shenandoah_barriers->at(idx);
50 }
51
52 void ShenandoahBarrierSetC2State::add_shenandoah_barrier(ShenandoahWriteBarrierNode * n) {
53 assert(!_shenandoah_barriers->contains(n), "duplicate entry in barrier list");
54 _shenandoah_barriers->append(n);
55 }
56
57 void ShenandoahBarrierSetC2State::remove_shenandoah_barrier(ShenandoahWriteBarrierNode * n) {
58 if (_shenandoah_barriers->contains(n)) {
59 _shenandoah_barriers->remove(n);
60 }
61 }
62
63 #define __ kit->
64
65 Node* ShenandoahBarrierSetC2::shenandoah_read_barrier(GraphKit* kit, Node* obj) const {
66 if (ShenandoahReadBarrier) {
67 obj = shenandoah_read_barrier_impl(kit, obj, false, true, true);
68 }
69 return obj;
70 }
71
72 Node* ShenandoahBarrierSetC2::shenandoah_storeval_barrier(GraphKit* kit, Node* obj) const {
73 if (ShenandoahStoreValEnqueueBarrier) {
74 obj = shenandoah_write_barrier(kit, obj);
75 obj = shenandoah_enqueue_barrier(kit, obj);
76 }
77 if (ShenandoahStoreValReadBarrier) {
78 obj = shenandoah_read_barrier_impl(kit, obj, true, false, false);
79 }
80 return obj;
81 }
82
83 Node* ShenandoahBarrierSetC2::shenandoah_read_barrier_impl(GraphKit* kit, Node* obj, bool use_ctrl, bool use_mem, bool allow_fromspace) const {
84 const Type* obj_type = obj->bottom_type();
85 if (obj_type->higher_equal(TypePtr::NULL_PTR)) {
86 return obj;
87 }
88 const TypePtr* adr_type = ShenandoahBarrierNode::brooks_pointer_type(obj_type);
89 Node* mem = use_mem ? __ memory(adr_type) : __ immutable_memory();
90
91 if (! ShenandoahBarrierNode::needs_barrier(&__ gvn(), NULL, obj, mem, allow_fromspace)) {
92 // We know it is null, no barrier needed.
93 return obj;
94 }
95
96 if (obj_type->meet(TypePtr::NULL_PTR) == obj_type->remove_speculative()) {
97
98 // We don't know if it's null or not. Need null-check.
99 enum { _not_null_path = 1, _null_path, PATH_LIMIT };
100 RegionNode* region = new RegionNode(PATH_LIMIT);
101 Node* phi = new PhiNode(region, obj_type);
102 Node* null_ctrl = __ top();
103 Node* not_null_obj = __ null_check_oop(obj, &null_ctrl);
104
105 region->init_req(_null_path, null_ctrl);
106 phi ->init_req(_null_path, __ zerocon(T_OBJECT));
107
108 Node* ctrl = use_ctrl ? __ control() : NULL;
109 ShenandoahReadBarrierNode* rb = new ShenandoahReadBarrierNode(ctrl, mem, not_null_obj, allow_fromspace);
110 Node* n = __ gvn().transform(rb);
111
112 region->init_req(_not_null_path, __ control());
113 phi ->init_req(_not_null_path, n);
114
115 __ set_control(__ gvn().transform(region));
116 __ record_for_igvn(region);
117 return __ gvn().transform(phi);
118
119 } else {
120 // We know it is not null. Simple barrier is sufficient.
121 Node* ctrl = use_ctrl ? __ control() : NULL;
122 ShenandoahReadBarrierNode* rb = new ShenandoahReadBarrierNode(ctrl, mem, obj, allow_fromspace);
123 Node* n = __ gvn().transform(rb);
124 __ record_for_igvn(n);
125 return n;
126 }
127 }
128
129 Node* ShenandoahBarrierSetC2::shenandoah_write_barrier_helper(GraphKit* kit, Node* obj, const TypePtr* adr_type) const {
130 ShenandoahWriteBarrierNode* wb = new ShenandoahWriteBarrierNode(kit->C, kit->control(), kit->memory(adr_type), obj);
131 Node* n = __ gvn().transform(wb);
132 if (n == wb) { // New barrier needs memory projection.
133 Node* proj = __ gvn().transform(new ShenandoahWBMemProjNode(n));
134 __ set_memory(proj, adr_type);
135 }
136 return n;
137 }
138
139 Node* ShenandoahBarrierSetC2::shenandoah_write_barrier(GraphKit* kit, Node* obj) const {
140 if (ShenandoahWriteBarrier) {
141 obj = shenandoah_write_barrier_impl(kit, obj);
142 }
143 return obj;
144 }
145
146 Node* ShenandoahBarrierSetC2::shenandoah_write_barrier_impl(GraphKit* kit, Node* obj) const {
147 if (! ShenandoahBarrierNode::needs_barrier(&__ gvn(), NULL, obj, NULL, true)) {
148 return obj;
149 }
150 const Type* obj_type = obj->bottom_type();
151 const TypePtr* adr_type = ShenandoahBarrierNode::brooks_pointer_type(obj_type);
152 Node* n = shenandoah_write_barrier_helper(kit, obj, adr_type);
153 __ record_for_igvn(n);
154 return n;
155 }
156
157 bool ShenandoahBarrierSetC2::satb_can_remove_pre_barrier(GraphKit* kit, PhaseTransform* phase, Node* adr,
158 BasicType bt, uint adr_idx) const {
159 intptr_t offset = 0;
160 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
161 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
162
163 if (offset == Type::OffsetBot) {
164 return false; // cannot unalias unless there are precise offsets
165 }
166
167 if (alloc == NULL) {
168 return false; // No allocation found
169 }
170
171 intptr_t size_in_bytes = type2aelembytes(bt);
172
173 Node* mem = __ memory(adr_idx); // start searching here...
174
175 for (int cnt = 0; cnt < 50; cnt++) {
176
177 if (mem->is_Store()) {
178
179 Node* st_adr = mem->in(MemNode::Address);
180 intptr_t st_offset = 0;
181 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
182
183 if (st_base == NULL) {
184 break; // inscrutable pointer
185 }
186
187 // Break we have found a store with same base and offset as ours so break
188 if (st_base == base && st_offset == offset) {
189 break;
190 }
191
192 if (st_offset != offset && st_offset != Type::OffsetBot) {
193 const int MAX_STORE = BytesPerLong;
194 if (st_offset >= offset + size_in_bytes ||
195 st_offset <= offset - MAX_STORE ||
196 st_offset <= offset - mem->as_Store()->memory_size()) {
197 // Success: The offsets are provably independent.
198 // (You may ask, why not just test st_offset != offset and be done?
199 // The answer is that stores of different sizes can co-exist
200 // in the same sequence of RawMem effects. We sometimes initialize
201 // a whole 'tile' of array elements with a single jint or jlong.)
202 mem = mem->in(MemNode::Memory);
203 continue; // advance through independent store memory
204 }
205 }
206
207 if (st_base != base
208 && MemNode::detect_ptr_independence(base, alloc, st_base,
209 AllocateNode::Ideal_allocation(st_base, phase),
210 phase)) {
211 // Success: The bases are provably independent.
212 mem = mem->in(MemNode::Memory);
213 continue; // advance through independent store memory
214 }
215 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
216
217 InitializeNode* st_init = mem->in(0)->as_Initialize();
218 AllocateNode* st_alloc = st_init->allocation();
219
220 // Make sure that we are looking at the same allocation site.
221 // The alloc variable is guaranteed to not be null here from earlier check.
222 if (alloc == st_alloc) {
223 // Check that the initialization is storing NULL so that no previous store
224 // has been moved up and directly write a reference
225 Node* captured_store = st_init->find_captured_store(offset,
226 type2aelembytes(T_OBJECT),
227 phase);
228 if (captured_store == NULL || captured_store == st_init->zero_memory()) {
229 return true;
230 }
231 }
232 }
233
234 // Unless there is an explicit 'continue', we must bail out here,
235 // because 'mem' is an inscrutable memory state (e.g., a call).
236 break;
237 }
238
239 return false;
240 }
241
242 #undef __
243 #define __ ideal.
244
245 void ShenandoahBarrierSetC2::satb_write_barrier_pre(GraphKit* kit,
246 bool do_load,
247 Node* obj,
248 Node* adr,
249 uint alias_idx,
250 Node* val,
251 const TypeOopPtr* val_type,
252 Node* pre_val,
253 BasicType bt) const {
254 // Some sanity checks
255 // Note: val is unused in this routine.
256
257 if (do_load) {
258 // We need to generate the load of the previous value
259 assert(obj != NULL, "must have a base");
260 assert(adr != NULL, "where are loading from?");
261 assert(pre_val == NULL, "loaded already?");
262 assert(val_type != NULL, "need a type");
263
264 if (ReduceInitialCardMarks
265 && satb_can_remove_pre_barrier(kit, &kit->gvn(), adr, bt, alias_idx)) {
266 return;
267 }
268
269 } else {
270 // In this case both val_type and alias_idx are unused.
271 assert(pre_val != NULL, "must be loaded already");
272 // Nothing to be done if pre_val is null.
273 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
274 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
275 }
276 assert(bt == T_OBJECT, "or we shouldn't be here");
277
278 IdealKit ideal(kit, true);
279
280 Node* tls = __ thread(); // ThreadLocalStorage
281
282 Node* no_base = __ top();
283 Node* zero = __ ConI(0);
284 Node* zeroX = __ ConX(0);
285
286 float likely = PROB_LIKELY(0.999);
287 float unlikely = PROB_UNLIKELY(0.999);
288
289 // Offsets into the thread
290 const int index_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset());
291 const int buffer_offset = in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset());
292
293 // Now the actual pointers into the thread
294 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
295 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
296
297 // Now some of the values
298 Node* marking;
299 Node* gc_state = __ AddP(no_base, tls, __ ConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset())));
300 Node* ld = __ load(__ ctrl(), gc_state, TypeInt::BYTE, T_BYTE, Compile::AliasIdxRaw);
301 marking = __ AndI(ld, __ ConI(ShenandoahHeap::MARKING));
302 assert(ShenandoahWriteBarrierNode::is_gc_state_load(ld), "Should match the shape");
303
304 // if (!marking)
305 __ if_then(marking, BoolTest::ne, zero, unlikely); {
306 BasicType index_bt = TypeX_X->basic_type();
307 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 SATBMarkQueue::_index with wrong size.");
308 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
309
310 if (do_load) {
311 // load original value
312 // alias_idx correct??
313 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
314 }
315
316 // if (pre_val != NULL)
317 __ if_then(pre_val, BoolTest::ne, kit->null()); {
318 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
319
320 // is the queue for this thread full?
321 __ if_then(index, BoolTest::ne, zeroX, likely); {
322
323 // decrement the index
324 Node* next_index = kit->gvn().transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
325
326 // Now get the buffer location we will log the previous value into and store it
327 Node *log_addr = __ AddP(no_base, buffer, next_index);
328 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
329 // update the index
330 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
331
332 } __ else_(); {
333
334 // logging buffer is full, call the runtime
335 const TypeFunc *tf = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type();
336 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), "shenandoah_wb_pre", pre_val, tls);
337 } __ end_if(); // (!index)
338 } __ end_if(); // (pre_val != NULL)
339 } __ end_if(); // (!marking)
340
341 // Final sync IdealKit and GraphKit.
342 kit->final_sync(ideal);
343
344 if (ShenandoahSATBBarrier && adr != NULL) {
345 Node* c = kit->control();
346 Node* call = c->in(1)->in(1)->in(1)->in(0);
347 assert(is_shenandoah_wb_pre_call(call), "shenandoah_wb_pre call expected");
348 call->add_req(adr);
349 }
350 }
351
352 bool ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(Node* call) {
353 return call->is_CallLeaf() &&
354 call->as_CallLeaf()->entry_point() == CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry);
355 }
356
357 bool ShenandoahBarrierSetC2::is_shenandoah_marking_if(PhaseTransform *phase, Node* n) {
358 if (n->Opcode() != Op_If) {
359 return false;
360 }
361
362 Node* bol = n->in(1);
363 assert(bol->is_Bool(), "");
364 Node* cmpx = bol->in(1);
365 if (bol->as_Bool()->_test._test == BoolTest::ne &&
366 cmpx->is_Cmp() && cmpx->in(2) == phase->intcon(0) &&
367 is_shenandoah_state_load(cmpx->in(1)->in(1)) &&
368 cmpx->in(1)->in(2)->is_Con() &&
369 cmpx->in(1)->in(2) == phase->intcon(ShenandoahHeap::MARKING)) {
370 return true;
371 }
372
373 return false;
374 }
375
376 bool ShenandoahBarrierSetC2::is_shenandoah_state_load(Node* n) {
377 if (!n->is_Load()) return false;
378 const int state_offset = in_bytes(ShenandoahThreadLocalData::gc_state_offset());
379 return n->in(2)->is_AddP() && n->in(2)->in(2)->Opcode() == Op_ThreadLocal
380 && n->in(2)->in(3)->is_Con()
381 && n->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == state_offset;
382 }
383
384 void ShenandoahBarrierSetC2::shenandoah_write_barrier_pre(GraphKit* kit,
385 bool do_load,
386 Node* obj,
387 Node* adr,
388 uint alias_idx,
389 Node* val,
390 const TypeOopPtr* val_type,
391 Node* pre_val,
392 BasicType bt) const {
393 if (ShenandoahSATBBarrier) {
394 IdealKit ideal(kit);
395 kit->sync_kit(ideal);
396
397 satb_write_barrier_pre(kit, do_load, obj, adr, alias_idx, val, val_type, pre_val, bt);
398
399 ideal.sync_kit(kit);
400 kit->final_sync(ideal);
401 }
402 }
403
404 Node* ShenandoahBarrierSetC2::shenandoah_enqueue_barrier(GraphKit* kit, Node* pre_val) const {
405 return kit->gvn().transform(new ShenandoahEnqueueBarrierNode(pre_val));
406 }
407
408 // Helper that guards and inserts a pre-barrier.
409 void ShenandoahBarrierSetC2::insert_pre_barrier(GraphKit* kit, Node* base_oop, Node* offset,
410 Node* pre_val, bool need_mem_bar) const {
411 // We could be accessing the referent field of a reference object. If so, when G1
412 // is enabled, we need to log the value in the referent field in an SATB buffer.
413 // This routine performs some compile time filters and generates suitable
414 // runtime filters that guard the pre-barrier code.
415 // Also add memory barrier for non volatile load from the referent field
416 // to prevent commoning of loads across safepoint.
417
418 // Some compile time checks.
419
420 // If offset is a constant, is it java_lang_ref_Reference::_reference_offset?
421 const TypeX* otype = offset->find_intptr_t_type();
422 if (otype != NULL && otype->is_con() &&
423 otype->get_con() != java_lang_ref_Reference::referent_offset) {
424 // Constant offset but not the reference_offset so just return
425 return;
426 }
427
428 // We only need to generate the runtime guards for instances.
429 const TypeOopPtr* btype = base_oop->bottom_type()->isa_oopptr();
430 if (btype != NULL) {
431 if (btype->isa_aryptr()) {
432 // Array type so nothing to do
433 return;
434 }
435
436 const TypeInstPtr* itype = btype->isa_instptr();
437 if (itype != NULL) {
438 // Can the klass of base_oop be statically determined to be
439 // _not_ a sub-class of Reference and _not_ Object?
440 ciKlass* klass = itype->klass();
441 if ( klass->is_loaded() &&
442 !klass->is_subtype_of(kit->env()->Reference_klass()) &&
443 !kit->env()->Object_klass()->is_subtype_of(klass)) {
444 return;
445 }
446 }
447 }
448
449 // The compile time filters did not reject base_oop/offset so
450 // we need to generate the following runtime filters
451 //
452 // if (offset == java_lang_ref_Reference::_reference_offset) {
453 // if (instance_of(base, java.lang.ref.Reference)) {
454 // pre_barrier(_, pre_val, ...);
455 // }
456 // }
457
458 float likely = PROB_LIKELY( 0.999);
459 float unlikely = PROB_UNLIKELY(0.999);
460
461 IdealKit ideal(kit);
462
463 Node* referent_off = __ ConX(java_lang_ref_Reference::referent_offset);
464
465 __ if_then(offset, BoolTest::eq, referent_off, unlikely); {
466 // Update graphKit memory and control from IdealKit.
467 kit->sync_kit(ideal);
468
469 Node* ref_klass_con = kit->makecon(TypeKlassPtr::make(kit->env()->Reference_klass()));
470 Node* is_instof = kit->gen_instanceof(base_oop, ref_klass_con);
471
472 // Update IdealKit memory and control from graphKit.
473 __ sync_kit(kit);
474
475 Node* one = __ ConI(1);
476 // is_instof == 0 if base_oop == NULL
477 __ if_then(is_instof, BoolTest::eq, one, unlikely); {
478
479 // Update graphKit from IdeakKit.
480 kit->sync_kit(ideal);
481
482 // Use the pre-barrier to record the value in the referent field
483 satb_write_barrier_pre(kit, false /* do_load */,
484 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
485 pre_val /* pre_val */,
486 T_OBJECT);
487 if (need_mem_bar) {
488 // Add memory barrier to prevent commoning reads from this field
489 // across safepoint since GC can change its value.
490 kit->insert_mem_bar(Op_MemBarCPUOrder);
491 }
492 // Update IdealKit from graphKit.
493 __ sync_kit(kit);
494
495 } __ end_if(); // _ref_type != ref_none
496 } __ end_if(); // offset == referent_offset
497
498 // Final sync IdealKit and GraphKit.
499 kit->final_sync(ideal);
500 }
501
502 #undef __
503
504 const TypeFunc* ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type() {
505 const Type **fields = TypeTuple::fields(2);
506 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
507 fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread
508 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
509
510 // create result type (range)
511 fields = TypeTuple::fields(0);
512 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
513
514 return TypeFunc::make(domain, range);
515 }
516
517 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
518 const Type **fields = TypeTuple::fields(1);
519 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
520 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
521
522 // create result type (range)
523 fields = TypeTuple::fields(0);
524 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields);
525
526 return TypeFunc::make(domain, range);
527 }
528
529 const TypeFunc* ShenandoahBarrierSetC2::shenandoah_write_barrier_Type() {
530 const Type **fields = TypeTuple::fields(1);
531 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
532 const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+1, fields);
533
534 // create result type (range)
535 fields = TypeTuple::fields(1);
536 fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL;
537 const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
538
539 return TypeFunc::make(domain, range);
540 }
541
542 Node* ShenandoahBarrierSetC2::store_at(C2Access& access, C2AccessValue& val) const {
543 // TODO: Implement using proper barriers.
544 return BarrierSetC2::store_at(access, val);
545 }
546
547 Node* ShenandoahBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
548 DecoratorSet decorators = access.decorators();
549 GraphKit* kit = access.kit();
550
551 const TypePtr* adr_type = access.addr().type();
552 Node* adr = access.addr().node();
553
554 bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
555 bool on_heap = (decorators & IN_HEAP) != 0;
556
557 if (!access.is_oop() || (!on_heap && !anonymous)) {
558 return BarrierSetC2::store_at_resolved(access, val);
559 }
560
561 uint adr_idx = kit->C->get_alias_index(adr_type);
562 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
563 Node* value = val.node();
564 value = shenandoah_storeval_barrier(kit, value);
565 val.set_node(value);
566 shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
567 static_cast<const TypeOopPtr*>(val.type()), NULL /* pre_val */, access.type());
568 return BarrierSetC2::store_at_resolved(access, val);
569 }
570
571 Node* ShenandoahBarrierSetC2::load_at(C2Access& access, const Type* val_type) const {
572 // TODO: Implement using proper barriers.
573 return BarrierSetC2::load_at(access, val_type);
574 }
575
576 Node* ShenandoahBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
577 DecoratorSet decorators = access.decorators();
578 GraphKit* kit = access.kit();
579
580 Node* adr = access.addr().node();
581 Node* obj = access.base();
582
583 bool mismatched = (decorators & C2_MISMATCHED) != 0;
584 bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
585 bool on_heap = (decorators & IN_HEAP) != 0;
586 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
587 bool is_unordered = (decorators & MO_UNORDERED) != 0;
588 bool need_cpu_mem_bar = !is_unordered || mismatched || !on_heap;
589
590 Node* offset = adr->is_AddP() ? adr->in(AddPNode::Offset) : kit->top();
591 Node* load = BarrierSetC2::load_at_resolved(access, val_type);
592
593 // If we are reading the value of the referent field of a Reference
594 // object (either by using Unsafe directly or through reflection)
595 // then, if SATB is enabled, we need to record the referent in an
596 // SATB log buffer using the pre-barrier mechanism.
597 // Also we need to add memory barrier to prevent commoning reads
598 // from this field across safepoint since GC can change its value.
599 bool need_read_barrier = ShenandoahKeepAliveBarrier &&
600 (on_heap && (on_weak || (unknown && offset != kit->top() && obj != kit->top())));
601
602 if (!access.is_oop() || !need_read_barrier) {
603 return load;
604 }
605
606 if (on_weak) {
607 // Use the pre-barrier to record the value in the referent field
608 satb_write_barrier_pre(kit, false /* do_load */,
609 NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
610 load /* pre_val */, T_OBJECT);
611 // Add memory barrier to prevent commoning reads from this field
612 // across safepoint since GC can change its value.
613 kit->insert_mem_bar(Op_MemBarCPUOrder);
614 } else if (unknown) {
615 // We do not require a mem bar inside pre_barrier if need_mem_bar
616 // is set: the barriers would be emitted by us.
617 insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
618 }
619
620 return load;
621 }
622
623 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val,
624 Node* val, const Type* value_type) const {
625 GraphKit* kit = access.kit();
626 if (access.is_oop()) {
627 val = shenandoah_storeval_barrier(kit, val);
628 shenandoah_write_barrier_pre(kit, false /* do_load */,
629 NULL, NULL, max_juint, NULL, NULL,
630 expected_val /* pre_val */, T_OBJECT);
631
632 }
633 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, val, value_type);
634 }
635
636 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_val_at(C2AtomicAccess& access, Node* expected_val,
637 Node* new_val, const Type* val_type) const {
638 // TODO: Implement using proper barriers.
639 return BarrierSetC2::atomic_cmpxchg_val_at(access, expected_val, new_val, val_type);
640 }
641
642 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val,
643 Node* val, const Type* value_type) const {
644 GraphKit* kit = access.kit();
645 if (access.is_oop()) {
646 val = shenandoah_storeval_barrier(kit, val);
647 shenandoah_write_barrier_pre(kit, false /* do_load */,
648 NULL, NULL, max_juint, NULL, NULL,
649 expected_val /* pre_val */, T_OBJECT);
650 }
651 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, val, value_type);
652 }
653
654 Node* ShenandoahBarrierSetC2::atomic_cmpxchg_bool_at(C2AtomicAccess& access, Node* expected_val,
655 Node* new_val, const Type* val_type) const {
656 // TODO: Implement using proper barriers.
657 return BarrierSetC2::atomic_cmpxchg_bool_at(access, expected_val, new_val, val_type);
658 }
659
660 Node* ShenandoahBarrierSetC2::atomic_xchg_at_resolved(C2AtomicAccess& access, Node* val, const Type* value_type) const {
661 GraphKit* kit = access.kit();
662 if (access.is_oop()) {
663 val = shenandoah_storeval_barrier(kit, val);
664 }
665 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
666 if (access.is_oop()) {
667 shenandoah_write_barrier_pre(kit, false /* do_load */,
668 NULL, NULL, max_juint, NULL, NULL,
669 result /* pre_val */, T_OBJECT);
670 }
671 return result;
672 }
673
674 Node* ShenandoahBarrierSetC2::atomic_xchg_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const {
675 // TODO: Implement using proper barriers.
676 return BarrierSetC2::atomic_xchg_at(access, new_val, value_type);
677 }
678
679 Node* ShenandoahBarrierSetC2::atomic_add_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const {
680 // TODO: Implement using proper barriers.
681 return BarrierSetC2::atomic_add_at(access, new_val, value_type);
682 }
683
684 void ShenandoahBarrierSetC2::clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const {
685 // TODO: Implement using proper barriers.
686 BarrierSetC2::clone(kit, src, dst, size, is_array);
687 }
688
689 Node* ShenandoahBarrierSetC2::resolve_for_read(GraphKit* kit, Node* n) const {
690 return shenandoah_read_barrier(kit, n);
691 }
692
693 Node* ShenandoahBarrierSetC2::resolve_for_write(GraphKit* kit, Node* n) const {
694 return shenandoah_write_barrier(kit, n);
695 }
696
697 // Support for GC barriers emitted during parsing
698 bool ShenandoahBarrierSetC2::is_gc_barrier_node(Node* node) const {
699 if (node->Opcode() != Op_CallLeaf && node->Opcode() != Op_CallLeafNoFP) {
700 return false;
701 }
702 CallLeafNode *call = node->as_CallLeaf();
703 if (call->_name == NULL) {
704 return false;
705 }
706
707 return strcmp(call->_name, "shenandoah_clone_barrier") == 0 ||
708 strcmp(call->_name, "shenandoah_cas_obj") == 0 ||
709 strcmp(call->_name, "shenandoah_wb_pre") == 0;
710 }
711
712 Node* ShenandoahBarrierSetC2::step_over_gc_barrier(Node* c) const {
713 // Currently not needed.
714 return c;
715 }
716
717 bool ShenandoahBarrierSetC2::array_copy_requires_gc_barriers(BasicType type) const {
718 return false;
719 }
720
721 // Support for macro expanded GC barriers
722 void ShenandoahBarrierSetC2::register_potential_barrier_node(Node* node) const {
723 if (node->Opcode() == Op_ShenandoahWriteBarrier) {
724 state()->add_shenandoah_barrier((ShenandoahWriteBarrierNode*) node);
725 }
726 }
727
728 void ShenandoahBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
729 if (node->Opcode() == Op_ShenandoahWriteBarrier) {
730 state()->remove_shenandoah_barrier((ShenandoahWriteBarrierNode*) node);
731 }
732 }
733
734 void ShenandoahBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* n) const {
735 if (is_shenandoah_wb_pre_call(n)) {
736 shenandoah_eliminate_wb_pre(n, ¯o->igvn());
737 }
738 }
739
740 void ShenandoahBarrierSetC2::shenandoah_eliminate_wb_pre(Node* call, PhaseIterGVN* igvn) const {
741 assert(UseShenandoahGC && is_shenandoah_wb_pre_call(call), "");
742 Node* c = call->as_Call()->proj_out(TypeFunc::Control);
743 c = c->unique_ctrl_out();
744 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
745 c = c->unique_ctrl_out();
746 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
747 Node* iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
748 assert(iff->is_If(), "expect test");
749 if (!is_shenandoah_marking_if(igvn, iff)) {
750 c = c->unique_ctrl_out();
751 assert(c->is_Region() && c->req() == 3, "where's the pre barrier control flow?");
752 iff = c->in(1)->is_IfProj() ? c->in(1)->in(0) : c->in(2)->in(0);
753 assert(is_shenandoah_marking_if(igvn, iff), "expect marking test");
754 }
755 Node* cmpx = iff->in(1)->in(1);
756 igvn->replace_node(cmpx, igvn->makecon(TypeInt::CC_EQ));
757 igvn->rehash_node_delayed(call);
758 call->del_req(call->req()-1);
759 }
760
761 void ShenandoahBarrierSetC2::enqueue_useful_gc_barrier(Unique_Node_List &worklist, Node* node) const {
762 }
763
764 void ShenandoahBarrierSetC2::eliminate_useless_gc_barriers(Unique_Node_List &useful) const {
765 for (int i = state()->shenandoah_barriers_count()-1; i >= 0; i--) {
766 ShenandoahWriteBarrierNode* n = state()->shenandoah_barrier(i);
767 if (!useful.member(n)) {
768 state()->remove_shenandoah_barrier(n);
769 }
770 }
771
772 }
773
774 void ShenandoahBarrierSetC2::add_users_to_worklist(Unique_Node_List* worklist) const {}
775
776 void* ShenandoahBarrierSetC2::create_barrier_state(Arena* comp_arena) const {
777 return new(comp_arena) ShenandoahBarrierSetC2State(comp_arena);
778 }
779
780 ShenandoahBarrierSetC2State* ShenandoahBarrierSetC2::state() const {
781 return reinterpret_cast<ShenandoahBarrierSetC2State*>(Compile::current()->barrier_set_state());
782 }
783
784 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
785 // expanded later, then now is the time to do so.
786 bool ShenandoahBarrierSetC2::expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
787 void ShenandoahBarrierSetC2::verify_gc_barriers(bool post_parse) const {
788 #ifdef ASSERT
789 if (ShenandoahVerifyOptoBarriers && !post_parse) {
790 ShenandoahBarrierNode::verify(Compile::current()->root());
791 }
792 #endif
793 }
794
795 Node* ShenandoahBarrierSetC2::ideal_node(PhaseGVN *phase, Node* n, bool can_reshape) const {
796 if (is_shenandoah_wb_pre_call(n)) {
797 uint cnt = ShenandoahBarrierSetC2::write_ref_field_pre_entry_Type()->domain()->cnt();
798 if (n->req() > cnt) {
799 Node* addp = n->in(cnt);
800 if (has_only_shenandoah_wb_pre_uses(addp)) {
801 n->del_req(cnt);
802 if (can_reshape) {
803 phase->is_IterGVN()->_worklist.push(addp);
804 }
805 return n;
806 }
807 }
808 }
809 return NULL;
810 }
811
812 bool ShenandoahBarrierSetC2::has_only_shenandoah_wb_pre_uses(Node* n) {
813 if (!UseShenandoahGC) {
814 return false;
815 }
816 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
817 Node* u = n->fast_out(i);
818 if (!is_shenandoah_wb_pre_call(u)) {
819 return false;
820 }
821 }
822 return n->outcnt() > 0;
823 }