1 /*
2 * Copyright (c) 2018, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "asm/macroAssembler.inline.hpp"
27 #include "gc/g1/g1BarrierSet.hpp"
28 #include "gc/g1/g1BarrierSetAssembler.hpp"
29 #include "gc/g1/g1BarrierSetRuntime.hpp"
30 #include "gc/g1/g1CardTable.hpp"
31 #include "gc/g1/g1HeapRegion.hpp"
32 #include "gc/g1/g1ThreadLocalData.hpp"
33 #include "interpreter/interp_masm.hpp"
34 #include "runtime/sharedRuntime.hpp"
35 #include "utilities/debug.hpp"
36 #include "utilities/macros.hpp"
37 #ifdef COMPILER1
38 #include "c1/c1_LIRAssembler.hpp"
39 #include "c1/c1_MacroAssembler.hpp"
40 #include "gc/g1/c1/g1BarrierSetC1.hpp"
41 #endif
42
43 #define __ masm->
44
45 void G1BarrierSetAssembler::gen_write_ref_array_pre_barrier(MacroAssembler* masm, DecoratorSet decorators,
46 Register addr, Register count) {
47 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
48
49 if (!dest_uninitialized) {
50 Register thread = NOT_LP64(rax) LP64_ONLY(r15_thread);
51 #ifndef _LP64
52 __ push(thread);
53 __ get_thread(thread);
54 #endif
55
56 Label filtered;
57 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
58 // Is marking active?
59 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
60 __ cmpl(in_progress, 0);
61 } else {
62 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
63 __ cmpb(in_progress, 0);
64 }
65
66 NOT_LP64(__ pop(thread);)
67
68 __ jcc(Assembler::equal, filtered);
69
70 __ push_call_clobbered_registers(false /* save_fpu */);
71 #ifdef _LP64
72 if (count == c_rarg0) {
73 if (addr == c_rarg1) {
74 // exactly backwards!!
75 __ xchgptr(c_rarg1, c_rarg0);
76 } else {
77 __ movptr(c_rarg1, count);
78 __ movptr(c_rarg0, addr);
79 }
80 } else {
81 __ movptr(c_rarg0, addr);
82 __ movptr(c_rarg1, count);
83 }
84 if (UseCompressedOops) {
85 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_narrow_oop_entry), 2);
86 } else {
87 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_oop_entry), 2);
88 }
89 #else
90 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_oop_entry),
91 addr, count);
92 #endif
93 __ pop_call_clobbered_registers(false /* save_fpu */);
94
95 __ bind(filtered);
96 }
97 }
98
99 void G1BarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
100 Register addr, Register count, Register tmp) {
101 __ push_call_clobbered_registers(false /* save_fpu */);
102 #ifdef _LP64
103 if (c_rarg0 == count) { // On win64 c_rarg0 == rcx
104 assert_different_registers(c_rarg1, addr);
105 __ mov(c_rarg1, count);
106 __ mov(c_rarg0, addr);
107 } else {
108 assert_different_registers(c_rarg0, count);
109 __ mov(c_rarg0, addr);
110 __ mov(c_rarg1, count);
111 }
112 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_post_entry), 2);
113 #else
114 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_post_entry),
115 addr, count);
116 #endif
117 __ pop_call_clobbered_registers(false /* save_fpu */);
118 }
119
120 void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
121 Register dst, Address src, Register tmp1, Register tmp_thread) {
122 bool on_oop = is_reference_type(type);
123 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
124 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
125 bool on_reference = on_weak || on_phantom;
126 ModRefBarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
127 if (on_oop && on_reference) {
128 Register thread = NOT_LP64(tmp_thread) LP64_ONLY(r15_thread);
129
130 #ifndef _LP64
131 // Work around the x86_32 bug that only manifests with Loom for some reason.
132 // MacroAssembler::resolve_weak_handle calls this barrier with tmp_thread == noreg.
133 if (thread == noreg) {
134 if (dst != rcx && tmp1 != rcx) {
135 thread = rcx;
136 } else if (dst != rdx && tmp1 != rdx) {
137 thread = rdx;
138 } else if (dst != rdi && tmp1 != rdi) {
139 thread = rdi;
140 }
141 }
142 assert_different_registers(dst, tmp1, thread);
143 __ push(thread);
144 __ get_thread(thread);
145 #endif
146
147 // Generate the G1 pre-barrier code to log the value of
148 // the referent field in an SATB buffer.
149 g1_write_barrier_pre(masm /* masm */,
150 noreg /* obj */,
151 dst /* pre_val */,
152 thread /* thread */,
153 tmp1 /* tmp */,
154 true /* tosca_live */,
155 true /* expand_call */);
156
157 #ifndef _LP64
158 __ pop(thread);
159 #endif
160 }
161 }
162
163 void G1BarrierSetAssembler::g1_write_barrier_pre(MacroAssembler* masm,
164 Register obj,
165 Register pre_val,
166 Register thread,
167 Register tmp,
168 bool tosca_live,
169 bool expand_call) {
170 // If expand_call is true then we expand the call_VM_leaf macro
171 // directly to skip generating the check by
172 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
173
174 #ifdef _LP64
175 assert(thread == r15_thread, "must be");
176 #endif // _LP64
177
178 Label done;
179 Label runtime;
180
181 assert(pre_val != noreg, "check this code");
182
183 if (obj != noreg) {
184 assert_different_registers(obj, pre_val, tmp);
185 assert(pre_val != rax, "check this code");
186 }
187
188 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
189 Address index(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()));
190 Address buffer(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()));
191
192 // Is marking active?
193 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
194 __ cmpl(in_progress, 0);
195 } else {
196 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
197 __ cmpb(in_progress, 0);
198 }
199 __ jcc(Assembler::equal, done);
200
201 // Do we need to load the previous value?
202 if (obj != noreg) {
203 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
204 }
205
206 // Is the previous value null?
207 __ cmpptr(pre_val, NULL_WORD);
208 __ jcc(Assembler::equal, done);
209
210 // Can we store original value in the thread's buffer?
211 // Is index == 0?
212 // (The index field is typed as size_t.)
213 __ movptr(tmp, index); // tmp := *index_adr
214 __ cmpptr(tmp, 0); // tmp == 0?
215 __ jcc(Assembler::equal, runtime); // If yes, goto runtime
216
217 __ subptr(tmp, wordSize); // tmp := tmp - wordSize
218 __ movptr(index, tmp); // *index_adr := tmp
219 __ addptr(tmp, buffer); // tmp := tmp + *buffer_adr
220
221 // Record the previous value
222 __ movptr(Address(tmp, 0), pre_val);
223 __ jmp(done);
224
225 __ bind(runtime);
226
227 if (EnableValhalla && InlineTypePassFieldsAsArgs) {
228 // Barriers might be emitted when converting between (scalarized) calling conventions for inline
229 // types. Save all argument registers before calling into the runtime.
230 // TODO: use push_set() (see JDK-8283327 push/pop_call_clobbered_registers & aarch64 )
231 __ pusha();
232 __ subptr(rsp, 64);
233 __ movdbl(Address(rsp, 0), j_farg0);
234 __ movdbl(Address(rsp, 8), j_farg1);
235 __ movdbl(Address(rsp, 16), j_farg2);
236 __ movdbl(Address(rsp, 24), j_farg3);
237 __ movdbl(Address(rsp, 32), j_farg4);
238 __ movdbl(Address(rsp, 40), j_farg5);
239 __ movdbl(Address(rsp, 48), j_farg6);
240 __ movdbl(Address(rsp, 56), j_farg7);
241 } else {
242 // Determine and save the live input values
243 __ push_call_clobbered_registers();
244 }
245
246 // Calling the runtime using the regular call_VM_leaf mechanism generates
247 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
248 // that checks that the *(ebp+frame::interpreter_frame_last_sp) == nullptr.
249 //
250 // If we care generating the pre-barrier without a frame (e.g. in the
251 // intrinsified Reference.get() routine) then ebp might be pointing to
252 // the caller frame and so this check will most likely fail at runtime.
253 //
254 // Expanding the call directly bypasses the generation of the check.
255 // So when we do not have have a full interpreter frame on the stack
256 // expand_call should be passed true.
257
258 if (expand_call) {
259 LP64_ONLY( assert(pre_val != c_rarg1, "smashed arg"); )
260 #ifdef _LP64
261 if (c_rarg1 != thread) {
262 __ mov(c_rarg1, thread);
263 }
264 if (c_rarg0 != pre_val) {
265 __ mov(c_rarg0, pre_val);
266 }
267 #else
268 __ push(thread);
269 __ push(pre_val);
270 #endif
271 __ MacroAssembler::call_VM_leaf_base(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), 2);
272 } else {
273 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
274 }
275
276 if (EnableValhalla && InlineTypePassFieldsAsArgs) {
277 // Restore registers
278 __ movdbl(j_farg0, Address(rsp, 0));
279 __ movdbl(j_farg1, Address(rsp, 8));
280 __ movdbl(j_farg2, Address(rsp, 16));
281 __ movdbl(j_farg3, Address(rsp, 24));
282 __ movdbl(j_farg4, Address(rsp, 32));
283 __ movdbl(j_farg5, Address(rsp, 40));
284 __ movdbl(j_farg6, Address(rsp, 48));
285 __ movdbl(j_farg7, Address(rsp, 56));
286 __ addptr(rsp, 64);
287 __ popa();
288 } else {
289 __ pop_call_clobbered_registers();
290 }
291
292 __ bind(done);
293 }
294
295 void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm,
296 Register store_addr,
297 Register new_val,
298 Register thread,
299 Register tmp,
300 Register tmp2) {
301 #ifdef _LP64
302 assert(thread == r15_thread, "must be");
303 #endif // _LP64
304
305 Address queue_index(thread, in_bytes(G1ThreadLocalData::dirty_card_queue_index_offset()));
306 Address buffer(thread, in_bytes(G1ThreadLocalData::dirty_card_queue_buffer_offset()));
307
308 CardTableBarrierSet* ct =
309 barrier_set_cast<CardTableBarrierSet>(BarrierSet::barrier_set());
310
311 Label done;
312 Label runtime;
313
314 // Does store cross heap regions?
315
316 __ movptr(tmp, store_addr);
317 __ xorptr(tmp, new_val);
318 __ shrptr(tmp, G1HeapRegion::LogOfHRGrainBytes);
319 __ jcc(Assembler::equal, done);
320
321 // crosses regions, storing null?
322
323 __ cmpptr(new_val, NULL_WORD);
324 __ jcc(Assembler::equal, done);
325
326 // storing region crossing non-null, is card already dirty?
327
328 const Register card_addr = tmp;
329 const Register cardtable = tmp2;
330
331 __ movptr(card_addr, store_addr);
332 __ shrptr(card_addr, CardTable::card_shift());
333 // Do not use ExternalAddress to load 'byte_map_base', since 'byte_map_base' is NOT
334 // a valid address and therefore is not properly handled by the relocation code.
335 __ movptr(cardtable, (intptr_t)ct->card_table()->byte_map_base());
336 __ addptr(card_addr, cardtable);
337
338 __ cmpb(Address(card_addr, 0), G1CardTable::g1_young_card_val());
339 __ jcc(Assembler::equal, done);
340
341 __ membar(Assembler::Membar_mask_bits(Assembler::StoreLoad));
342 __ cmpb(Address(card_addr, 0), G1CardTable::dirty_card_val());
343 __ jcc(Assembler::equal, done);
344
345
346 // storing a region crossing, non-null oop, card is clean.
347 // dirty card and log.
348
349 __ movb(Address(card_addr, 0), G1CardTable::dirty_card_val());
350
351 // The code below assumes that buffer index is pointer sized.
352 STATIC_ASSERT(in_bytes(G1DirtyCardQueue::byte_width_of_index()) == sizeof(intptr_t));
353
354 __ movptr(tmp2, queue_index);
355 __ testptr(tmp2, tmp2);
356 __ jcc(Assembler::zero, runtime);
357 __ subptr(tmp2, wordSize);
358 __ movptr(queue_index, tmp2);
359 __ addptr(tmp2, buffer);
360 __ movptr(Address(tmp2, 0), card_addr);
361 __ jmp(done);
362
363 __ bind(runtime);
364 // Barriers might be emitted when converting between (scalarized) calling conventions for inline
365 // types. Save all argument registers before calling into the runtime.
366 // TODO: use push_set() (see JDK-8283327 push/pop_call_clobbered_registers & aarch64)
367 __ pusha();
368 __ subptr(rsp, 64);
369 __ movdbl(Address(rsp, 0), j_farg0);
370 __ movdbl(Address(rsp, 8), j_farg1);
371 __ movdbl(Address(rsp, 16), j_farg2);
372 __ movdbl(Address(rsp, 24), j_farg3);
373 __ movdbl(Address(rsp, 32), j_farg4);
374 __ movdbl(Address(rsp, 40), j_farg5);
375 __ movdbl(Address(rsp, 48), j_farg6);
376 __ movdbl(Address(rsp, 56), j_farg7);
377
378 #ifdef _LP64
379 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry), card_addr, r15_thread);
380 #else
381 __ push(thread);
382 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry), card_addr, thread);
383 __ pop(thread);
384 #endif
385
386 // Restore registers
387 __ movdbl(j_farg0, Address(rsp, 0));
388 __ movdbl(j_farg1, Address(rsp, 8));
389 __ movdbl(j_farg2, Address(rsp, 16));
390 __ movdbl(j_farg3, Address(rsp, 24));
391 __ movdbl(j_farg4, Address(rsp, 32));
392 __ movdbl(j_farg5, Address(rsp, 40));
393 __ movdbl(j_farg6, Address(rsp, 48));
394 __ movdbl(j_farg7, Address(rsp, 56));
395 __ addptr(rsp, 64);
396 __ popa();
397
398 __ bind(done);
399 }
400
401 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
402 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
403 bool in_heap = (decorators & IN_HEAP) != 0;
404 bool as_normal = (decorators & AS_NORMAL) != 0;
405 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
406
407 bool needs_pre_barrier = as_normal && !dest_uninitialized;
408 bool needs_post_barrier = val != noreg && in_heap;
409
410 Register rthread = LP64_ONLY(r15_thread) NOT_LP64(rcx);
411 // flatten object address if needed
412 // We do it regardless of precise because we need the registers
413 if (dst.index() == noreg && dst.disp() == 0) {
414 if (dst.base() != tmp1) {
415 __ movptr(tmp1, dst.base());
416 }
417 } else {
418 __ lea(tmp1, dst);
419 }
420
421 #ifndef _LP64
422 InterpreterMacroAssembler *imasm = static_cast<InterpreterMacroAssembler*>(masm);
423 #endif
424
425 NOT_LP64(__ get_thread(rcx));
426 NOT_LP64(imasm->save_bcp());
427
428 if (needs_pre_barrier) {
429 g1_write_barrier_pre(masm /*masm*/,
430 tmp1 /* obj */,
431 tmp2 /* pre_val */,
432 rthread /* thread */,
433 tmp3 /* tmp */,
434 val != noreg /* tosca_live */,
435 false /* expand_call */);
436 }
437 if (val == noreg) {
438 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp1, 0), val, noreg, noreg, noreg);
439 } else {
440 Register new_val = val;
441 if (needs_post_barrier) {
442 // G1 barrier needs uncompressed oop for region cross check.
443 if (UseCompressedOops) {
444 new_val = tmp2;
445 __ movptr(new_val, val);
446 }
447 }
448 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp1, 0), val, noreg, noreg, noreg);
449 if (needs_post_barrier) {
450 g1_write_barrier_post(masm /*masm*/,
451 tmp1 /* store_adr */,
452 new_val /* new_val */,
453 rthread /* thread */,
454 tmp3 /* tmp */,
455 tmp2 /* tmp2 */);
456 }
457 }
458 NOT_LP64(imasm->restore_bcp());
459 }
460
461 #ifdef COMPILER1
462
463 #undef __
464 #define __ ce->masm()->
465
466 void G1BarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, G1PreBarrierStub* stub) {
467 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
468 // At this point we know that marking is in progress.
469 // If do_load() is true then we have to emit the
470 // load of the previous value; otherwise it has already
471 // been loaded into _pre_val.
472
473 __ bind(*stub->entry());
474 assert(stub->pre_val()->is_register(), "Precondition.");
475
476 Register pre_val_reg = stub->pre_val()->as_register();
477
478 if (stub->do_load()) {
479 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/);
480 }
481
482 __ cmpptr(pre_val_reg, NULL_WORD);
483 __ jcc(Assembler::equal, *stub->continuation());
484 ce->store_parameter(stub->pre_val()->as_register(), 0);
485 __ call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
486 __ jmp(*stub->continuation());
487
488 }
489
490 void G1BarrierSetAssembler::gen_post_barrier_stub(LIR_Assembler* ce, G1PostBarrierStub* stub) {
491 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
492 __ bind(*stub->entry());
493 assert(stub->addr()->is_register(), "Precondition.");
494 assert(stub->new_val()->is_register(), "Precondition.");
495 Register new_val_reg = stub->new_val()->as_register();
496 __ cmpptr(new_val_reg, NULL_WORD);
497 __ jcc(Assembler::equal, *stub->continuation());
498 ce->store_parameter(stub->addr()->as_pointer_register(), 0);
499 __ call(RuntimeAddress(bs->post_barrier_c1_runtime_code_blob()->code_begin()));
500 __ jmp(*stub->continuation());
501 }
502
503 #undef __
504
505 #define __ sasm->
506
507 void G1BarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
508 // Generated code assumes that buffer index is pointer sized.
509 STATIC_ASSERT(in_bytes(SATBMarkQueue::byte_width_of_index()) == sizeof(intptr_t));
510
511 __ prologue("g1_pre_barrier", false);
512 // arg0 : previous value of memory
513
514 __ push(rax);
515 __ push(rdx);
516
517 const Register pre_val = rax;
518 const Register thread = NOT_LP64(rax) LP64_ONLY(r15_thread);
519 const Register tmp = rdx;
520
521 NOT_LP64(__ get_thread(thread);)
522
523 Address queue_active(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
524 Address queue_index(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()));
525 Address buffer(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()));
526
527 Label done;
528 Label runtime;
529
530 // Is marking still active?
531 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
532 __ cmpl(queue_active, 0);
533 } else {
534 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
535 __ cmpb(queue_active, 0);
536 }
537 __ jcc(Assembler::equal, done);
538
539 // Can we store original value in the thread's buffer?
540
541 __ movptr(tmp, queue_index);
542 __ testptr(tmp, tmp);
543 __ jcc(Assembler::zero, runtime);
544 __ subptr(tmp, wordSize);
545 __ movptr(queue_index, tmp);
546 __ addptr(tmp, buffer);
547
548 // prev_val (rax)
549 __ load_parameter(0, pre_val);
550 __ movptr(Address(tmp, 0), pre_val);
551 __ jmp(done);
552
553 __ bind(runtime);
554
555 __ push_call_clobbered_registers();
556
557 // load the pre-value
558 __ load_parameter(0, rcx);
559 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), rcx, thread);
560
561 __ pop_call_clobbered_registers();
562
563 __ bind(done);
564
565 __ pop(rdx);
566 __ pop(rax);
567
568 __ epilogue();
569 }
570
571 void G1BarrierSetAssembler::generate_c1_post_barrier_runtime_stub(StubAssembler* sasm) {
572 __ prologue("g1_post_barrier", false);
573
574 CardTableBarrierSet* ct =
575 barrier_set_cast<CardTableBarrierSet>(BarrierSet::barrier_set());
576
577 Label done;
578 Label enqueued;
579 Label runtime;
580
581 // At this point we know new_value is non-null and the new_value crosses regions.
582 // Must check to see if card is already dirty
583
584 const Register thread = NOT_LP64(rax) LP64_ONLY(r15_thread);
585
586 Address queue_index(thread, in_bytes(G1ThreadLocalData::dirty_card_queue_index_offset()));
587 Address buffer(thread, in_bytes(G1ThreadLocalData::dirty_card_queue_buffer_offset()));
588
589 __ push(rax);
590 __ push(rcx);
591
592 const Register cardtable = rax;
593 const Register card_addr = rcx;
594
595 __ load_parameter(0, card_addr);
596 __ shrptr(card_addr, CardTable::card_shift());
597 // Do not use ExternalAddress to load 'byte_map_base', since 'byte_map_base' is NOT
598 // a valid address and therefore is not properly handled by the relocation code.
599 __ movptr(cardtable, (intptr_t)ct->card_table()->byte_map_base());
600 __ addptr(card_addr, cardtable);
601
602 NOT_LP64(__ get_thread(thread);)
603
604 __ cmpb(Address(card_addr, 0), G1CardTable::g1_young_card_val());
605 __ jcc(Assembler::equal, done);
606
607 __ membar(Assembler::Membar_mask_bits(Assembler::StoreLoad));
608 __ cmpb(Address(card_addr, 0), CardTable::dirty_card_val());
609 __ jcc(Assembler::equal, done);
610
611 // storing region crossing non-null, card is clean.
612 // dirty card and log.
613
614 __ movb(Address(card_addr, 0), CardTable::dirty_card_val());
615
616 const Register tmp = rdx;
617 __ push(rdx);
618
619 __ movptr(tmp, queue_index);
620 __ testptr(tmp, tmp);
621 __ jcc(Assembler::zero, runtime);
622 __ subptr(tmp, wordSize);
623 __ movptr(queue_index, tmp);
624 __ addptr(tmp, buffer);
625 __ movptr(Address(tmp, 0), card_addr);
626 __ jmp(enqueued);
627
628 __ bind(runtime);
629 __ push_call_clobbered_registers();
630
631 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry), card_addr, thread);
632
633 __ pop_call_clobbered_registers();
634
635 __ bind(enqueued);
636 __ pop(rdx);
637
638 __ bind(done);
639 __ pop(rcx);
640 __ pop(rax);
641
642 __ epilogue();
643 }
644
645 #undef __
646
647 #endif // COMPILER1
--- EOF ---