1 /*
2 * Copyright (c) 2018, 2026, 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 "code/aotCodeCache.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/arguments.hpp"
35 #include "runtime/sharedRuntime.hpp"
36 #include "utilities/debug.hpp"
37 #include "utilities/macros.hpp"
38 #ifdef COMPILER1
39 #include "c1/c1_LIRAssembler.hpp"
40 #include "c1/c1_MacroAssembler.hpp"
41 #include "gc/g1/c1/g1BarrierSetC1.hpp"
42 #endif // COMPILER1
43 #ifdef COMPILER2
44 #include "gc/g1/c2/g1BarrierSetC2.hpp"
45 #endif // COMPILER2
46
47 #define __ masm->
48
49 void G1BarrierSetAssembler::gen_write_ref_array_pre_barrier(MacroAssembler* masm, DecoratorSet decorators,
50 Register addr, Register count) {
51 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
52
53 if (!dest_uninitialized) {
54 Register thread = r15_thread;
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 __ jcc(Assembler::equal, filtered);
67
68 __ push_call_clobbered_registers(false /* save_fpu */);
69 if (count == c_rarg0) {
70 if (addr == c_rarg1) {
71 // exactly backwards!!
72 __ xchgptr(c_rarg1, c_rarg0);
73 } else {
74 __ movptr(c_rarg1, count);
75 __ movptr(c_rarg0, addr);
76 }
77 } else {
78 __ movptr(c_rarg0, addr);
79 __ movptr(c_rarg1, count);
80 }
81 if (UseCompressedOops) {
82 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_narrow_oop_entry), 2);
83 } else {
84 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_oop_entry), 2);
85 }
86 __ pop_call_clobbered_registers(false /* save_fpu */);
87
88 __ bind(filtered);
89 }
90 }
91
92 void G1BarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
93 Register addr, Register count, Register tmp) {
94 Label L_done;
95
96 __ testptr(count, count);
97 __ jccb(Assembler::zero, L_done);
98
99 // Calculate end address in "count".
100 Address::ScaleFactor scale = UseCompressedOops ? Address::times_4 : Address::times_8;
101 __ leaq(count, Address(addr, count, scale));
102
103 // Calculate start card address in "addr".
104 __ shrptr(addr, CardTable::card_shift());
105
106 Register thread = r15_thread;
107
108 __ movptr(tmp, Address(thread, in_bytes(G1ThreadLocalData::card_table_base_offset())));
109 __ addptr(addr, tmp);
110
111 // Calculate address of card of last word in the array.
112 __ subptr(count, 1);
113 __ shrptr(count, CardTable::card_shift());
114 __ addptr(count, tmp);
115
116 Label L_loop;
117 // Iterate from start card to end card (inclusive).
118 __ bind(L_loop);
119
120 Label L_is_clean_card;
121 if (UseCondCardMark) {
122 __ cmpb(Address(addr, 0), G1CardTable::clean_card_val());
123 __ jccb(Assembler::equal, L_is_clean_card);
124 } else {
125 __ movb(Address(addr, 0), G1CardTable::dirty_card_val());
126 }
127
128 Label L_next_card;
129 __ bind(L_next_card);
130 __ addptr(addr, sizeof(CardTable::CardValue));
131 __ cmpptr(addr, count);
132 __ jccb(Assembler::belowEqual, L_loop);
133 __ jmpb(L_done);
134
135 __ bind(L_is_clean_card);
136 // Card was clean. Dirty card and go to next.
137 __ movb(Address(addr, 0), G1CardTable::dirty_card_val());
138 __ jmpb(L_next_card);
139
140 __ bind(L_done);
141 }
142
143 void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
144 Register dst, Address src, Register tmp1) {
145 bool on_oop = is_reference_type(type);
146 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
147 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
148 bool on_reference = on_weak || on_phantom;
149 CardTableBarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1);
150 if (on_oop && on_reference) {
151 // Generate the G1 pre-barrier code to log the value of
152 // the referent field in an SATB buffer.
153 g1_write_barrier_pre(masm /* masm */,
154 noreg /* obj */,
155 dst /* pre_val */,
156 tmp1 /* tmp */,
157 true /* tosca_live */,
158 true /* expand_call */);
159 }
160 }
161
162 static void generate_pre_barrier_fast_path(MacroAssembler* masm,
163 const Register thread) {
164 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
165 // Is marking active?
166 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
167 __ cmpl(in_progress, 0);
168 } else {
169 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
170 __ cmpb(in_progress, 0);
171 }
172 }
173
174 static void generate_pre_barrier_slow_path(MacroAssembler* masm,
175 const Register obj,
176 const Register pre_val,
177 const Register thread,
178 const Register tmp,
179 Label& L_done) {
180 Address index_addr(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()));
181 Address buffer_addr(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()));
182
183 // This code assumes that buffer index is pointer sized.
184 STATIC_ASSERT(in_bytes(SATBMarkQueue::byte_width_of_index()) == sizeof(intptr_t));
185
186 Label L_runtime;
187
188 // Do we need to load the previous value?
189 if (obj != noreg) {
190 __ load_heap_oop(pre_val, Address(obj, 0), noreg, AS_RAW);
191 }
192
193 // Is the previous value null?
194 __ testptr(pre_val, pre_val);
195 __ jcc(Assembler::equal, L_done);
196
197 // Can we store a value in the given thread's buffer?
198 // (The index field is typed as size_t.)
199 __ movptr(tmp, index_addr); // temp := *(index address)
200 __ testptr(tmp, tmp); // index == 0?
201 __ jccb(Assembler::zero, L_runtime); // jump to runtime if index == 0 (full buffer)
202
203 // The buffer is not full, store value into it.
204 __ subptr(tmp, wordSize); // temp := next index
205 __ movptr(index_addr, tmp); // *(index address) := next index
206 __ addptr(tmp, buffer_addr); // temp := buffer address + next index
207 __ movptr(Address(tmp, 0), pre_val); // *(buffer address + next index) := value
208
209 // Jump out if done, or fall-through to runtime.
210 // "L_done" is far away, so jump cannot be short.
211 __ jmp(L_done);
212 __ bind(L_runtime);
213 }
214
215 void G1BarrierSetAssembler::g1_write_barrier_pre(MacroAssembler* masm,
216 Register obj,
217 Register pre_val,
218 Register tmp,
219 bool tosca_live,
220 bool expand_call) {
221 // If expand_call is true then we expand the call_VM_leaf macro
222 // directly to skip generating the check by
223 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
224 const Register thread = r15_thread;
225
226 Label done;
227
228 assert(pre_val != noreg, "check this code");
229
230 if (obj != noreg) {
231 assert_different_registers(obj, pre_val, tmp);
232 assert(pre_val != rax, "check this code");
233 }
234
235 generate_pre_barrier_fast_path(masm, thread);
236 // If marking is not active (*(mark queue active address) == 0), jump to done
237 __ jcc(Assembler::equal, done);
238 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp, done);
239
240 // Determine and save the live input values
241 __ push_call_clobbered_registers();
242
243 // Calling the runtime using the regular call_VM_leaf mechanism generates
244 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
245 // that checks that the *(ebp+frame::interpreter_frame_last_sp) == nullptr.
246 //
247 // If we care generating the pre-barrier without a frame (e.g. in the
248 // intrinsified Reference.get() routine) then ebp might be pointing to
249 // the caller frame and so this check will most likely fail at runtime.
250 //
251 // Expanding the call directly bypasses the generation of the check.
252 // So when we do not have have a full interpreter frame on the stack
253 // expand_call should be passed true.
254
255 if (expand_call) {
256 assert(pre_val != c_rarg1, "smashed arg");
257 if (c_rarg1 != thread) {
258 __ mov(c_rarg1, thread);
259 }
260 if (c_rarg0 != pre_val) {
261 __ mov(c_rarg0, pre_val);
262 }
263 __ MacroAssembler::call_VM_leaf_base(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), 2);
264 } else {
265 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
266 }
267
268 __ pop_call_clobbered_registers();
269
270 __ bind(done);
271 }
272
273 #if INCLUDE_CDS
274 // return a register that differs from reg1, reg2, reg3 and reg4
275
276 static Register pick_different_reg(Register reg1, Register reg2 = noreg, Register reg3= noreg, Register reg4 = noreg) {
277 RegSet available = (RegSet::of(rscratch1, rscratch2, rax, rbx) + rdx -
278 RegSet::of(reg1, reg2, reg3, reg4));
279 return *(available.begin());
280 }
281 #endif // INCLUDE_CDS
282
283 static void generate_post_barrier(MacroAssembler* masm,
284 const Register store_addr,
285 const Register new_val,
286 const Register tmp1,
287 bool new_val_may_be_null) {
288
289 assert_different_registers(store_addr, new_val, tmp1, noreg);
290
291 Register thread = r15_thread;
292
293 Label L_done;
294 // Does store cross heap regions?
295 #if INCLUDE_CDS
296 // AOT code needs to load the barrier grain shift from the aot
297 // runtime constants area in the code cache otherwise we can compile
298 // it as an immediate operand
299
300 if (AOTCodeCache::is_on_for_dump()) {
301 address grain_shift_addr = AOTRuntimeConstants::grain_shift_address();
302 Register save = pick_different_reg(rcx, tmp1, new_val, store_addr);
303 __ push(save);
304 __ movptr(save, store_addr);
305 __ xorptr(save, new_val);
306 __ push(rcx);
307 __ lea(rcx, ExternalAddress(grain_shift_addr));
308 __ movl(rcx, Address(rcx, 0));
309 __ shrptr(save);
310 __ pop(rcx);
311 __ pop(save);
312 __ jcc(Assembler::equal, L_done);
313 } else
314 #endif // INCLUDE_CDS
315 {
316 __ movptr(tmp1, store_addr); // tmp1 := store address
317 __ xorptr(tmp1, new_val); // tmp1 := store address ^ new value
318 __ shrptr(tmp1, G1HeapRegion::LogOfHRGrainBytes); // ((store address ^ new value) >> LogOfHRGrainBytes) == 0?
319 __ jccb(Assembler::equal, L_done);
320 }
321
322 // Crosses regions, storing null?
323 if (new_val_may_be_null) {
324 __ testptr(new_val, new_val); // new value == null?
325 __ jccb(Assembler::equal, L_done);
326 }
327
328 __ movptr(tmp1, store_addr); // tmp1 := store address
329 __ shrptr(tmp1, CardTable::card_shift()); // tmp1 := card address relative to card table base
330
331 Address card_table_addr(thread, in_bytes(G1ThreadLocalData::card_table_base_offset()));
332 __ addptr(tmp1, card_table_addr); // tmp1 := card address
333 if (UseCondCardMark) {
334 __ cmpb(Address(tmp1, 0), G1CardTable::clean_card_val()); // *(card address) == clean_card_val?
335 __ jccb(Assembler::notEqual, L_done);
336 }
337 // Storing a region crossing, non-null oop, card is clean.
338 // Dirty card.
339 __ movb(Address(tmp1, 0), G1CardTable::dirty_card_val()); // *(card address) := dirty_card_val
340 __ bind(L_done);
341 }
342
343 void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm,
344 Register store_addr,
345 Register new_val,
346 Register tmp) {
347 generate_post_barrier(masm, store_addr, new_val, tmp, true /* new_val_may_be_null */);
348 }
349
350 #if defined(COMPILER2)
351
352 static void generate_c2_barrier_runtime_call(MacroAssembler* masm, G1BarrierStubC2* stub, const Register arg, const address runtime_path) {
353 SaveLiveRegisters save_registers(masm, stub);
354 if (c_rarg0 != arg) {
355 __ mov(c_rarg0, arg);
356 }
357 __ mov(c_rarg1, r15_thread);
358 // rax is a caller-saved, non-argument-passing register, so it does not
359 // interfere with c_rarg0 or c_rarg1. If it contained any live value before
360 // entering this stub, it is saved at this point, and restored after the
361 // call. If it did not contain any live value, it is free to be used. In
362 // either case, it is safe to use it here as a call scratch register.
363 __ call(RuntimeAddress(runtime_path), rax);
364 }
365
366 void G1BarrierSetAssembler::g1_write_barrier_pre_c2(MacroAssembler* masm,
367 Register obj,
368 Register pre_val,
369 Register tmp,
370 G1PreBarrierStubC2* stub) {
371 const Register thread = r15_thread;
372
373 assert(pre_val != noreg, "check this code");
374 if (obj != noreg) {
375 assert_different_registers(obj, pre_val, tmp);
376 }
377
378 stub->initialize_registers(obj, pre_val, thread, tmp);
379
380 generate_pre_barrier_fast_path(masm, thread);
381 // If marking is active (*(mark queue active address) != 0), jump to stub (slow path)
382 __ jcc(Assembler::notEqual, *stub->entry());
383
384 __ bind(*stub->continuation());
385 }
386
387 void G1BarrierSetAssembler::generate_c2_pre_barrier_stub(MacroAssembler* masm,
388 G1PreBarrierStubC2* stub) const {
389 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
390 Register obj = stub->obj();
391 Register pre_val = stub->pre_val();
392 Register thread = stub->thread();
393 Register tmp = stub->tmp1();
394 assert(stub->tmp2() == noreg, "not needed in this platform");
395
396 __ bind(*stub->entry());
397 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp, *stub->continuation());
398
399 generate_c2_barrier_runtime_call(masm, stub, pre_val, CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry));
400 __ jmp(*stub->continuation());
401 }
402
403 void G1BarrierSetAssembler::g1_write_barrier_post_c2(MacroAssembler* masm,
404 Register store_addr,
405 Register new_val,
406 Register tmp,
407 bool new_val_may_be_null) {
408 generate_post_barrier(masm, store_addr, new_val, tmp, new_val_may_be_null);
409 }
410
411 #endif // COMPILER2
412
413 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
414 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
415 bool in_heap = (decorators & IN_HEAP) != 0;
416 bool as_normal = (decorators & AS_NORMAL) != 0;
417 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
418
419 bool needs_pre_barrier = as_normal && !dest_uninitialized;
420 bool needs_post_barrier = val != noreg && in_heap;
421
422 // flatten object address if needed
423 // We do it regardless of precise because we need the registers
424 if (dst.index() == noreg && dst.disp() == 0) {
425 if (dst.base() != tmp1) {
426 __ movptr(tmp1, dst.base());
427 }
428 } else {
429 __ lea(tmp1, dst);
430 }
431
432 if (needs_pre_barrier) {
433 g1_write_barrier_pre(masm /*masm*/,
434 tmp1 /* obj */,
435 tmp2 /* pre_val */,
436 tmp3 /* tmp */,
437 val != noreg /* tosca_live */,
438 false /* expand_call */);
439 }
440 if (val == noreg) {
441 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp1, 0), val, noreg, noreg, noreg);
442 } else {
443 Register new_val = val;
444 if (needs_post_barrier) {
445 // G1 barrier needs uncompressed oop for region cross check.
446 if (UseCompressedOops) {
447 new_val = tmp2;
448 __ movptr(new_val, val);
449 }
450 }
451 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp1, 0), val, noreg, noreg, noreg);
452 if (needs_post_barrier) {
453 g1_write_barrier_post(masm /*masm*/,
454 tmp1 /* store_adr */,
455 new_val /* new_val */,
456 tmp3 /* tmp */);
457 }
458 }
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 __ testptr(pre_val_reg, pre_val_reg);
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 #undef __
491
492 void G1BarrierSetAssembler::g1_write_barrier_post_c1(MacroAssembler* masm,
493 Register store_addr,
494 Register new_val,
495 Register thread,
496 Register tmp1,
497 Register tmp2 /* unused on x86 */) {
498 generate_post_barrier(masm, store_addr, new_val, tmp1, true /* new_val_may_be_null */);
499 }
500
501 #define __ sasm->
502
503 void G1BarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
504 // Generated code assumes that buffer index is pointer sized.
505 STATIC_ASSERT(in_bytes(SATBMarkQueue::byte_width_of_index()) == sizeof(intptr_t));
506
507 __ prologue("g1_pre_barrier", false);
508 // arg0 : previous value of memory
509
510 __ push_ppx(rax);
511 __ push_ppx(rdx);
512
513 const Register pre_val = rax;
514 const Register thread = r15_thread;
515 const Register tmp = rdx;
516
517 Address queue_active(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
518 Address queue_index(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()));
519 Address buffer(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()));
520
521 Label L_done, L_runtime;
522
523 // Is marking still active?
524 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
525 __ cmpl(queue_active, 0);
526 } else {
527 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
528 __ cmpb(queue_active, 0);
529 }
530 __ jcc(Assembler::equal, L_done);
531
532 // Can we store original value in the thread's buffer?
533
534 __ movptr(tmp, queue_index);
535 __ testptr(tmp, tmp);
536 __ jccb(Assembler::zero, L_runtime);
537 __ subptr(tmp, wordSize);
538 __ movptr(queue_index, tmp);
539 __ addptr(tmp, buffer);
540
541 // prev_val (rax)
542 __ load_parameter(0, pre_val);
543 __ movptr(Address(tmp, 0), pre_val);
544 __ jmp(L_done);
545
546 __ bind(L_runtime);
547
548 __ push_call_clobbered_registers();
549
550 // load the pre-value
551 __ load_parameter(0, rcx);
552 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), rcx, thread);
553
554 __ pop_call_clobbered_registers();
555
556 __ bind(L_done);
557
558 __ pop_ppx(rdx);
559 __ pop_ppx(rax);
560
561 __ epilogue();
562 }
563
564 #undef __
565
566 #endif // COMPILER1