1 /*
2 * Copyright (c) 2018, 2025, 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 "asm/macroAssembler.inline.hpp"
26 #include "gc/g1/g1BarrierSet.hpp"
27 #include "gc/g1/g1BarrierSetAssembler.hpp"
28 #include "gc/g1/g1BarrierSetRuntime.hpp"
29 #include "gc/g1/g1CardTable.hpp"
30 #include "gc/g1/g1HeapRegion.hpp"
31 #include "gc/g1/g1ThreadLocalData.hpp"
32 #include "gc/shared/collectedHeap.hpp"
33 #include "interpreter/interp_masm.hpp"
34 #include "runtime/javaThread.hpp"
35 #include "runtime/sharedRuntime.hpp"
36 #ifdef COMPILER1
37 #include "c1/c1_LIRAssembler.hpp"
38 #include "c1/c1_MacroAssembler.hpp"
39 #include "gc/g1/c1/g1BarrierSetC1.hpp"
40 #endif // COMPILER1
41 #ifdef COMPILER2
42 #include "gc/g1/c2/g1BarrierSetC2.hpp"
43 #endif // COMPILER2
44
45 #define __ masm->
46
47 void G1BarrierSetAssembler::gen_write_ref_array_pre_barrier(MacroAssembler* masm, DecoratorSet decorators,
48 Register addr, Register count, RegSet saved_regs) {
49 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
50 if (!dest_uninitialized) {
51 Label done;
52 Address in_progress(rthread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
53
54 // Is marking active?
55 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
56 __ ldrw(rscratch1, in_progress);
57 } else {
58 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
59 __ ldrb(rscratch1, in_progress);
60 }
61 __ cbzw(rscratch1, done);
62
63 __ push(saved_regs, sp);
64 if (count == c_rarg0) {
65 if (addr == c_rarg1) {
66 // exactly backwards!!
67 __ mov(rscratch1, c_rarg0);
68 __ mov(c_rarg0, c_rarg1);
69 __ mov(c_rarg1, rscratch1);
70 } else {
71 __ mov(c_rarg1, count);
72 __ mov(c_rarg0, addr);
73 }
74 } else {
75 __ mov(c_rarg0, addr);
76 __ mov(c_rarg1, count);
77 }
78 if (UseCompressedOops) {
79 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_narrow_oop_entry), 2);
80 } else {
81 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_oop_entry), 2);
82 }
83 __ pop(saved_regs, sp);
84
85 __ bind(done);
86 }
87 }
88
89 void G1BarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
90 Register start, Register count, Register scratch, RegSet saved_regs) {
91 __ push(saved_regs, sp);
92 assert_different_registers(start, count, scratch);
93 assert_different_registers(c_rarg0, count);
94 __ mov(c_rarg0, start);
95 __ mov(c_rarg1, count);
96 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_post_entry), 2);
97 __ pop(saved_regs, sp);
98 }
99
100 static void generate_queue_test_and_insertion(MacroAssembler* masm, ByteSize index_offset, ByteSize buffer_offset, Label& runtime,
101 const Register thread, const Register value, const Register temp1, const Register temp2) {
102 // Can we store a value in the given thread's buffer?
103 // (The index field is typed as size_t.)
104 __ ldr(temp1, Address(thread, in_bytes(index_offset))); // temp1 := *(index address)
105 __ cbz(temp1, runtime); // jump to runtime if index == 0 (full buffer)
106 // The buffer is not full, store value into it.
107 __ sub(temp1, temp1, wordSize); // temp1 := next index
108 __ str(temp1, Address(thread, in_bytes(index_offset))); // *(index address) := next index
109 __ ldr(temp2, Address(thread, in_bytes(buffer_offset))); // temp2 := buffer address
110 __ str(value, Address(temp2, temp1)); // *(buffer address + next index) := value
111 }
112
113 static void generate_pre_barrier_fast_path(MacroAssembler* masm,
114 const Register thread,
115 const Register tmp1) {
116 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
117 // Is marking active?
118 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
119 __ ldrw(tmp1, in_progress);
120 } else {
121 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
122 __ ldrb(tmp1, in_progress);
123 }
124 }
125
126 static void generate_pre_barrier_slow_path(MacroAssembler* masm,
127 const Register obj,
128 const Register pre_val,
129 const Register thread,
130 const Register tmp1,
131 const Register tmp2,
132 Label& done,
133 Label& runtime) {
134 // Do we need to load the previous value?
135 if (obj != noreg) {
136 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
137 }
138 // Is the previous value null?
139 __ cbz(pre_val, done);
140 generate_queue_test_and_insertion(masm,
141 G1ThreadLocalData::satb_mark_queue_index_offset(),
142 G1ThreadLocalData::satb_mark_queue_buffer_offset(),
143 runtime,
144 thread, pre_val, tmp1, tmp2);
145 __ b(done);
146 }
147
148 void G1BarrierSetAssembler::g1_write_barrier_pre(MacroAssembler* masm,
149 Register obj,
150 Register pre_val,
151 Register thread,
152 Register tmp1,
153 Register tmp2,
154 bool tosca_live,
155 bool expand_call) {
156 // If expand_call is true then we expand the call_VM_leaf macro
157 // directly to skip generating the check by
158 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
159
160 assert(thread == rthread, "must be");
161
162 Label done;
163 Label runtime;
164
165 assert_different_registers(obj, pre_val, tmp1, tmp2);
166 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
167
168 generate_pre_barrier_fast_path(masm, thread, tmp1);
169 // If marking is not active (*(mark queue active address) == 0), jump to done
170 __ cbzw(tmp1, done);
171 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp1, tmp2, done, runtime);
172
173 __ bind(runtime);
174
175 __ push_call_clobbered_registers();
176
177 // Calling the runtime using the regular call_VM_leaf mechanism generates
178 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
179 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == nullptr.
180 //
181 // If we care generating the pre-barrier without a frame (e.g. in the
182 // intrinsified Reference.get() routine) then rfp might be pointing to
183 // the caller frame and so this check will most likely fail at runtime.
184 //
185 // Expanding the call directly bypasses the generation of the check.
186 // So when we do not have have a full interpreter frame on the stack
187 // expand_call should be passed true.
188
189 if (expand_call) {
190 assert(pre_val != c_rarg1, "smashed arg");
191 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
192 } else {
193 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
194 }
195
196 __ pop_call_clobbered_registers();
197
198 __ bind(done);
199
200 }
201
202 static void generate_post_barrier_fast_path(MacroAssembler* masm,
203 const Register store_addr,
204 const Register new_val,
205 const Register tmp1,
206 const Register tmp2,
207 Label& done,
208 bool new_val_may_be_null) {
209 // Does store cross heap regions?
210 __ eor(tmp1, store_addr, new_val); // tmp1 := store address ^ new value
211 __ lsr(tmp1, tmp1, G1HeapRegion::LogOfHRGrainBytes); // tmp1 := ((store address ^ new value) >> LogOfHRGrainBytes)
212 __ cbz(tmp1, done);
213 // Crosses regions, storing null?
214 if (new_val_may_be_null) {
215 __ cbz(new_val, done);
216 }
217 // Storing region crossing non-null, is card young?
218 __ lsr(tmp1, store_addr, CardTable::card_shift()); // tmp1 := card address relative to card table base
219 __ load_byte_map_base(tmp2); // tmp2 := card table base address
220 __ add(tmp1, tmp1, tmp2); // tmp1 := card address
221 __ ldrb(tmp2, Address(tmp1)); // tmp2 := card
222 __ cmpw(tmp2, (int)G1CardTable::g1_young_card_val()); // tmp2 := card == young_card_val?
223 }
224
225 static void generate_post_barrier_slow_path(MacroAssembler* masm,
226 const Register thread,
227 const Register tmp1,
228 const Register tmp2,
229 Label& done,
230 Label& runtime) {
231 __ membar(Assembler::StoreLoad); // StoreLoad membar
232 __ ldrb(tmp2, Address(tmp1)); // tmp2 := card
233 __ cbzw(tmp2, done);
234 // Storing a region crossing, non-null oop, card is clean.
235 // Dirty card and log.
236 STATIC_ASSERT(CardTable::dirty_card_val() == 0);
237 __ strb(zr, Address(tmp1)); // *(card address) := dirty_card_val
238 generate_queue_test_and_insertion(masm,
239 G1ThreadLocalData::dirty_card_queue_index_offset(),
240 G1ThreadLocalData::dirty_card_queue_buffer_offset(),
241 runtime,
242 thread, tmp1, tmp2, rscratch1);
243 __ b(done);
244 }
245
246 void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm,
247 Register store_addr,
248 Register new_val,
249 Register thread,
250 Register tmp1,
251 Register tmp2) {
252 assert(thread == rthread, "must be");
253 assert_different_registers(store_addr, new_val, thread, tmp1, tmp2,
254 rscratch1);
255 assert(store_addr != noreg && new_val != noreg && tmp1 != noreg
256 && tmp2 != noreg, "expecting a register");
257
258 Label done;
259 Label runtime;
260
261 generate_post_barrier_fast_path(masm, store_addr, new_val, tmp1, tmp2, done, true /* new_val_may_be_null */);
262 // If card is young, jump to done
263 __ br(Assembler::EQ, done);
264 generate_post_barrier_slow_path(masm, thread, tmp1, tmp2, done, runtime);
265
266 __ bind(runtime);
267 // save the live input values
268 RegSet saved = RegSet::of(store_addr);
269 __ push(saved, sp);
270 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry), tmp1, thread);
271 __ pop(saved, sp);
272
273 __ bind(done);
274 }
275
276 #if defined(COMPILER2)
277
278 static void generate_c2_barrier_runtime_call(MacroAssembler* masm, G1BarrierStubC2* stub, const Register arg, const address runtime_path) {
279 SaveLiveRegisters save_registers(masm, stub);
280 if (c_rarg0 != arg) {
281 __ mov(c_rarg0, arg);
282 }
283 __ mov(c_rarg1, rthread);
284 __ mov(rscratch1, runtime_path);
285 __ blr(rscratch1);
286 }
287
288 void G1BarrierSetAssembler::g1_write_barrier_pre_c2(MacroAssembler* masm,
289 Register obj,
290 Register pre_val,
291 Register thread,
292 Register tmp1,
293 Register tmp2,
294 G1PreBarrierStubC2* stub) {
295 assert(thread == rthread, "must be");
296 assert_different_registers(obj, pre_val, tmp1, tmp2);
297 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
298
299 stub->initialize_registers(obj, pre_val, thread, tmp1, tmp2);
300
301 generate_pre_barrier_fast_path(masm, thread, tmp1);
302 // If marking is active (*(mark queue active address) != 0), jump to stub (slow path)
303 __ cbnzw(tmp1, *stub->entry());
304
305 __ bind(*stub->continuation());
306 }
307
308 void G1BarrierSetAssembler::generate_c2_pre_barrier_stub(MacroAssembler* masm,
309 G1PreBarrierStubC2* stub) const {
310 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
311 Label runtime;
312 Register obj = stub->obj();
313 Register pre_val = stub->pre_val();
314 Register thread = stub->thread();
315 Register tmp1 = stub->tmp1();
316 Register tmp2 = stub->tmp2();
317
318 __ bind(*stub->entry());
319 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp1, tmp2, *stub->continuation(), runtime);
320
321 __ bind(runtime);
322 generate_c2_barrier_runtime_call(masm, stub, pre_val, CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry));
323 __ b(*stub->continuation());
324 }
325
326 void G1BarrierSetAssembler::g1_write_barrier_post_c2(MacroAssembler* masm,
327 Register store_addr,
328 Register new_val,
329 Register thread,
330 Register tmp1,
331 Register tmp2,
332 G1PostBarrierStubC2* stub) {
333 assert(thread == rthread, "must be");
334 assert_different_registers(store_addr, new_val, thread, tmp1, tmp2,
335 rscratch1);
336 assert(store_addr != noreg && new_val != noreg && tmp1 != noreg
337 && tmp2 != noreg, "expecting a register");
338
339 stub->initialize_registers(thread, tmp1, tmp2);
340
341 bool new_val_may_be_null = (stub->barrier_data() & G1C2BarrierPostNotNull) == 0;
342 generate_post_barrier_fast_path(masm, store_addr, new_val, tmp1, tmp2, *stub->continuation(), new_val_may_be_null);
343 // If card is not young, jump to stub (slow path)
344 __ br(Assembler::NE, *stub->entry());
345
346 __ bind(*stub->continuation());
347 }
348
349 void G1BarrierSetAssembler::generate_c2_post_barrier_stub(MacroAssembler* masm,
350 G1PostBarrierStubC2* stub) const {
351 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
352 Label runtime;
353 Register thread = stub->thread();
354 Register tmp1 = stub->tmp1(); // tmp1 holds the card address.
355 Register tmp2 = stub->tmp2();
356 assert(stub->tmp3() == noreg, "not needed in this platform");
357
358 __ bind(*stub->entry());
359 generate_post_barrier_slow_path(masm, thread, tmp1, tmp2, *stub->continuation(), runtime);
360
361 __ bind(runtime);
362 generate_c2_barrier_runtime_call(masm, stub, tmp1, CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry));
363 __ b(*stub->continuation());
364 }
365
366 #endif // COMPILER2
367
368 void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
369 Register dst, Address src, Register tmp1, Register tmp2) {
370 bool on_oop = is_reference_type(type);
371 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
372 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
373 bool on_reference = on_weak || on_phantom;
374 ModRefBarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
375 if (on_oop && on_reference) {
376 // LR is live. It must be saved around calls.
377 __ enter(/*strip_ret_addr*/true); // barrier may call runtime
378 // Generate the G1 pre-barrier code to log the value of
379 // the referent field in an SATB buffer.
380 g1_write_barrier_pre(masm /* masm */,
381 noreg /* obj */,
382 dst /* pre_val */,
383 rthread /* thread */,
384 tmp1 /* tmp1 */,
385 tmp2 /* tmp2 */,
386 true /* tosca_live */,
387 true /* expand_call */);
388 __ leave();
389 }
390 }
391
392 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
393 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
394 // flatten object address if needed
395 if (dst.index() == noreg && dst.offset() == 0) {
396 if (dst.base() != tmp3) {
397 __ mov(tmp3, dst.base());
398 }
399 } else {
400 __ lea(tmp3, dst);
401 }
402
403 g1_write_barrier_pre(masm,
404 tmp3 /* obj */,
405 tmp2 /* pre_val */,
406 rthread /* thread */,
407 tmp1 /* tmp1 */,
408 rscratch2 /* tmp2 */,
409 val != noreg /* tosca_live */,
410 false /* expand_call */);
411
412 if (val == noreg) {
413 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), noreg, noreg, noreg, noreg);
414 } else {
415 // G1 barrier needs uncompressed oop for region cross check.
416 Register new_val = val;
417 if (UseCompressedOops) {
418 new_val = rscratch2;
419 __ mov(new_val, val);
420 }
421 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), val, noreg, noreg, noreg);
422 g1_write_barrier_post(masm,
423 tmp3 /* store_adr */,
424 new_val /* new_val */,
425 rthread /* thread */,
426 tmp1 /* tmp1 */,
427 tmp2 /* tmp2 */);
428 }
429
430 }
431
432 #ifdef COMPILER1
433
434 #undef __
435 #define __ ce->masm()->
436
437 void G1BarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, G1PreBarrierStub* stub) {
438 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
439 // At this point we know that marking is in progress.
440 // If do_load() is true then we have to emit the
441 // load of the previous value; otherwise it has already
442 // been loaded into _pre_val.
443
444 __ bind(*stub->entry());
445
446 assert(stub->pre_val()->is_register(), "Precondition.");
447
448 Register pre_val_reg = stub->pre_val()->as_register();
449
450 if (stub->do_load()) {
451 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/);
452 }
453 __ cbz(pre_val_reg, *stub->continuation());
454 ce->store_parameter(stub->pre_val()->as_register(), 0);
455 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
456 __ b(*stub->continuation());
457 }
458
459 void G1BarrierSetAssembler::gen_post_barrier_stub(LIR_Assembler* ce, G1PostBarrierStub* stub) {
460 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
461 __ bind(*stub->entry());
462 assert(stub->addr()->is_register(), "Precondition.");
463 assert(stub->new_val()->is_register(), "Precondition.");
464 Register new_val_reg = stub->new_val()->as_register();
465 __ cbz(new_val_reg, *stub->continuation());
466 ce->store_parameter(stub->addr()->as_pointer_register(), 0);
467 __ far_call(RuntimeAddress(bs->post_barrier_c1_runtime_code_blob()->code_begin()));
468 __ b(*stub->continuation());
469 }
470
471 #undef __
472
473 #define __ sasm->
474
475 void G1BarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
476 __ prologue("g1_pre_barrier", false);
477
478 // arg0 : previous value of memory
479
480 BarrierSet* bs = BarrierSet::barrier_set();
481
482 const Register pre_val = r0;
483 const Register thread = rthread;
484 const Register tmp = rscratch1;
485
486 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
487 Address queue_index(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()));
488 Address buffer(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()));
489
490 Label done;
491 Label runtime;
492
493 // Is marking still active?
494 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
495 __ ldrw(tmp, in_progress);
496 } else {
497 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
498 __ ldrb(tmp, in_progress);
499 }
500 __ cbzw(tmp, done);
501
502 // Can we store original value in the thread's buffer?
503 __ ldr(tmp, queue_index);
504 __ cbz(tmp, runtime);
505
506 __ sub(tmp, tmp, wordSize);
507 __ str(tmp, queue_index);
508 __ ldr(rscratch2, buffer);
509 __ add(tmp, tmp, rscratch2);
510 __ load_parameter(0, rscratch2);
511 __ str(rscratch2, Address(tmp, 0));
512 __ b(done);
513
514 __ bind(runtime);
515 __ push_call_clobbered_registers();
516 __ load_parameter(0, pre_val);
517 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
518 __ pop_call_clobbered_registers();
519 __ bind(done);
520
521 __ epilogue();
522 }
523
524 void G1BarrierSetAssembler::generate_c1_post_barrier_runtime_stub(StubAssembler* sasm) {
525 __ prologue("g1_post_barrier", false);
526
527 // arg0: store_address
528 Address store_addr(rfp, 2*BytesPerWord);
529
530 BarrierSet* bs = BarrierSet::barrier_set();
531 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
532 CardTable* ct = ctbs->card_table();
533
534 Label done;
535 Label runtime;
536
537 // At this point we know new_value is non-null and the new_value crosses regions.
538 // Must check to see if card is already dirty
539
540 const Register thread = rthread;
541
542 Address queue_index(thread, in_bytes(G1ThreadLocalData::dirty_card_queue_index_offset()));
543 Address buffer(thread, in_bytes(G1ThreadLocalData::dirty_card_queue_buffer_offset()));
544
545 const Register card_offset = rscratch2;
546 // LR is free here, so we can use it to hold the byte_map_base.
547 const Register byte_map_base = lr;
548
549 assert_different_registers(card_offset, byte_map_base, rscratch1);
550
551 __ load_parameter(0, card_offset);
552 __ lsr(card_offset, card_offset, CardTable::card_shift());
553 __ load_byte_map_base(byte_map_base);
554 __ ldrb(rscratch1, Address(byte_map_base, card_offset));
555 __ cmpw(rscratch1, (int)G1CardTable::g1_young_card_val());
556 __ br(Assembler::EQ, done);
557
558 assert((int)CardTable::dirty_card_val() == 0, "must be 0");
559
560 __ membar(Assembler::StoreLoad);
561 __ ldrb(rscratch1, Address(byte_map_base, card_offset));
562 __ cbzw(rscratch1, done);
563
564 // storing region crossing non-null, card is clean.
565 // dirty card and log.
566 __ strb(zr, Address(byte_map_base, card_offset));
567
568 // Convert card offset into an address in card_addr
569 Register card_addr = card_offset;
570 __ add(card_addr, byte_map_base, card_addr);
571
572 __ ldr(rscratch1, queue_index);
573 __ cbz(rscratch1, runtime);
574 __ sub(rscratch1, rscratch1, wordSize);
575 __ str(rscratch1, queue_index);
576
577 // Reuse LR to hold buffer_addr
578 const Register buffer_addr = lr;
579
580 __ ldr(buffer_addr, buffer);
581 __ str(card_addr, Address(buffer_addr, rscratch1));
582 __ b(done);
583
584 __ bind(runtime);
585 __ push_call_clobbered_registers();
586 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry), card_addr, thread);
587 __ pop_call_clobbered_registers();
588 __ bind(done);
589 __ epilogue();
590 }
591
592 #undef __
593
594 #endif // COMPILER1