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 "interpreter/interp_masm.hpp"
33 #include "runtime/sharedRuntime.hpp"
34 #include "utilities/debug.hpp"
35 #include "utilities/macros.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) {
49 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
50
51 if (!dest_uninitialized) {
52 Register thread = r15_thread;
53
54 Label filtered;
55 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
56 // Is marking active?
57 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
58 __ cmpl(in_progress, 0);
59 } else {
60 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
61 __ cmpb(in_progress, 0);
62 }
63
64 __ jcc(Assembler::equal, filtered);
65
66 __ push_call_clobbered_registers(false /* save_fpu */);
67 if (count == c_rarg0) {
68 if (addr == c_rarg1) {
69 // exactly backwards!!
70 __ xchgptr(c_rarg1, c_rarg0);
71 } else {
72 __ movptr(c_rarg1, count);
73 __ movptr(c_rarg0, addr);
74 }
75 } else {
76 __ movptr(c_rarg0, addr);
77 __ movptr(c_rarg1, count);
78 }
79 if (UseCompressedOops) {
80 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_narrow_oop_entry), 2);
81 } else {
82 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_array_pre_oop_entry), 2);
83 }
84 __ pop_call_clobbered_registers(false /* save_fpu */);
85
86 __ bind(filtered);
87 }
88 }
89
90 void G1BarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
91 Register addr, Register count, Register tmp) {
92 Label done;
93
94 __ testptr(count, count);
95 __ jcc(Assembler::zero, done);
96
97 // Calculate end address in "count".
98 Address::ScaleFactor scale = UseCompressedOops ? Address::times_4 : Address::times_8;
99 __ leaq(count, Address(addr, count, scale));
100
101 // Calculate start card address in "addr".
102 __ shrptr(addr, CardTable::card_shift());
103
104 Register thread = r15_thread;
105
106 __ movptr(tmp, Address(thread, in_bytes(G1ThreadLocalData::card_table_base_offset())));
107 __ addptr(addr, tmp);
108
109 // Calculate address of card of last word in the array.
110 __ subptr(count, 1);
111 __ shrptr(count, CardTable::card_shift());
112 __ addptr(count, tmp);
113
114 Label loop;
115 // Iterate from start card to end card (inclusive).
116 __ bind(loop);
117
118 Label is_clean_card;
119 if (UseCondCardMark) {
120 __ cmpb(Address(addr, 0), G1CardTable::clean_card_val());
121 __ jcc(Assembler::equal, is_clean_card);
122 } else {
123 __ movb(Address(addr, 0), G1CardTable::dirty_card_val());
124 }
125
126 Label next_card;
127 __ bind(next_card);
128 __ addptr(addr, sizeof(CardTable::CardValue));
129 __ cmpptr(addr, count);
130 __ jcc(Assembler::belowEqual, loop);
131 __ jmp(done);
132
133 __ bind(is_clean_card);
134 // Card was clean. Dirty card and go to next..
135 __ movb(Address(addr, 0), G1CardTable::dirty_card_val());
136 __ jmp(next_card);
137
138 __ bind(done);
139 }
140
141 void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
142 Register dst, Address src, Register tmp1) {
143 bool on_oop = is_reference_type(type);
144 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
145 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
146 bool on_reference = on_weak || on_phantom;
147 ModRefBarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1);
148 if (on_oop && on_reference) {
149 // Generate the G1 pre-barrier code to log the value of
150 // the referent field in an SATB buffer.
151 g1_write_barrier_pre(masm /* masm */,
152 noreg /* obj */,
153 dst /* pre_val */,
154 tmp1 /* tmp */,
155 true /* tosca_live */,
156 true /* expand_call */);
157 }
158 }
159
160 static void generate_queue_insertion(MacroAssembler* masm, ByteSize index_offset, ByteSize buffer_offset, Label& runtime,
161 const Register thread, const Register value, const Register temp) {
162 // This code assumes that buffer index is pointer sized.
163 STATIC_ASSERT(in_bytes(SATBMarkQueue::byte_width_of_index()) == sizeof(intptr_t));
164 // Can we store a value in the given thread's buffer?
165 // (The index field is typed as size_t.)
166 __ movptr(temp, Address(thread, in_bytes(index_offset))); // temp := *(index address)
167 __ testptr(temp, temp); // index == 0?
168 __ jcc(Assembler::zero, runtime); // jump to runtime if index == 0 (full buffer)
169 // The buffer is not full, store value into it.
170 __ subptr(temp, wordSize); // temp := next index
171 __ movptr(Address(thread, in_bytes(index_offset)), temp); // *(index address) := next index
172 __ addptr(temp, Address(thread, in_bytes(buffer_offset))); // temp := buffer address + next index
173 __ movptr(Address(temp, 0), value); // *(buffer address + next index) := value
174 }
175
176 static void generate_pre_barrier_fast_path(MacroAssembler* masm,
177 const Register thread) {
178 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
179 // Is marking active?
180 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
181 __ cmpl(in_progress, 0);
182 } else {
183 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
184 __ cmpb(in_progress, 0);
185 }
186 }
187
188 static void generate_pre_barrier_slow_path(MacroAssembler* masm,
189 const Register obj,
190 const Register pre_val,
191 const Register thread,
192 const Register tmp,
193 Label& done,
194 Label& runtime) {
195 // Do we need to load the previous value?
196 if (obj != noreg) {
197 __ load_heap_oop(pre_val, Address(obj, 0), noreg, AS_RAW);
198 }
199 // Is the previous value null?
200 __ cmpptr(pre_val, NULL_WORD);
201 __ jcc(Assembler::equal, done);
202 generate_queue_insertion(masm,
203 G1ThreadLocalData::satb_mark_queue_index_offset(),
204 G1ThreadLocalData::satb_mark_queue_buffer_offset(),
205 runtime,
206 thread, pre_val, tmp);
207 __ jmp(done);
208 }
209
210 void G1BarrierSetAssembler::g1_write_barrier_pre(MacroAssembler* masm,
211 Register obj,
212 Register pre_val,
213 Register tmp,
214 bool tosca_live,
215 bool expand_call) {
216 // If expand_call is true then we expand the call_VM_leaf macro
217 // directly to skip generating the check by
218 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
219 const Register thread = r15_thread;
220
221 Label done;
222 Label runtime;
223
224 assert(pre_val != noreg, "check this code");
225
226 if (obj != noreg) {
227 assert_different_registers(obj, pre_val, tmp);
228 assert(pre_val != rax, "check this code");
229 }
230
231 generate_pre_barrier_fast_path(masm, thread);
232 // If marking is not active (*(mark queue active address) == 0), jump to done
233 __ jcc(Assembler::equal, done);
234 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp, done, runtime);
235
236 __ bind(runtime);
237
238 // Determine and save the live input values
239 __ push_call_clobbered_registers();
240
241 // Calling the runtime using the regular call_VM_leaf mechanism generates
242 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
243 // that checks that the *(ebp+frame::interpreter_frame_last_sp) == nullptr.
244 //
245 // If we care generating the pre-barrier without a frame (e.g. in the
246 // intrinsified Reference.get() routine) then ebp might be pointing to
247 // the caller frame and so this check will most likely fail at runtime.
248 //
249 // Expanding the call directly bypasses the generation of the check.
250 // So when we do not have have a full interpreter frame on the stack
251 // expand_call should be passed true.
252
253 if (expand_call) {
254 assert(pre_val != c_rarg1, "smashed arg");
255 if (c_rarg1 != thread) {
256 __ mov(c_rarg1, thread);
257 }
258 if (c_rarg0 != pre_val) {
259 __ mov(c_rarg0, pre_val);
260 }
261 __ MacroAssembler::call_VM_leaf_base(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), 2);
262 } else {
263 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
264 }
265
266 __ pop_call_clobbered_registers();
267
268 __ bind(done);
269 }
270
271 static void generate_post_barrier_fast_path(MacroAssembler* masm,
272 const Register store_addr,
273 const Register new_val,
274 const Register tmp1,
275 Label& done,
276 bool new_val_may_be_null) {
277
278 assert_different_registers(store_addr, new_val, tmp1, noreg);
279
280 Register thread = r15_thread;
281
282 // Does store cross heap regions?
283 __ movptr(tmp1, store_addr); // tmp1 := store address
284 __ xorptr(tmp1, new_val); // tmp1 := store address ^ new value
285 __ shrptr(tmp1, G1HeapRegion::LogOfHRGrainBytes); // ((store address ^ new value) >> LogOfHRGrainBytes) == 0?
286 __ jcc(Assembler::equal, done);
287
288 // Crosses regions, storing null?
289 if (new_val_may_be_null) {
290 __ cmpptr(new_val, NULL_WORD); // new value == null?
291 __ jcc(Assembler::equal, done);
292 }
293
294 __ movptr(tmp1, store_addr); // tmp1 := store address
295 __ shrptr(tmp1, CardTable::card_shift()); // tmp1 := card address relative to card table base
296
297 Address card_table_addr(thread, in_bytes(G1ThreadLocalData::card_table_base_offset()));
298 __ addptr(tmp1, card_table_addr); // tmp1 := card address
299 if (UseCondCardMark) {
300 __ cmpb(Address(tmp1, 0), G1CardTable::clean_card_val()); // *(card address) == clean_card_val?
301 __ jcc(Assembler::notEqual, done);
302 }
303 // Storing a region crossing, non-null oop, card is clean.
304 // Dirty card.
305 __ movb(Address(tmp1, 0), G1CardTable::dirty_card_val()); // *(card address) := dirty_card_val
306 }
307
308 void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm,
309 Register store_addr,
310 Register new_val,
311 Register tmp) {
312 Label done;
313 generate_post_barrier_fast_path(masm, store_addr, new_val, tmp, done, true /* new_val_may_be_null */);
314 __ bind(done);
315 }
316
317 #if defined(COMPILER2)
318
319 static void generate_c2_barrier_runtime_call(MacroAssembler* masm, G1BarrierStubC2* stub, const Register arg, const address runtime_path) {
320 SaveLiveRegisters save_registers(masm, stub);
321 if (c_rarg0 != arg) {
322 __ mov(c_rarg0, arg);
323 }
324 __ mov(c_rarg1, r15_thread);
325 // rax is a caller-saved, non-argument-passing register, so it does not
326 // interfere with c_rarg0 or c_rarg1. If it contained any live value before
327 // entering this stub, it is saved at this point, and restored after the
328 // call. If it did not contain any live value, it is free to be used. In
329 // either case, it is safe to use it here as a call scratch register.
330 __ call(RuntimeAddress(runtime_path), rax);
331 }
332
333 void G1BarrierSetAssembler::g1_write_barrier_pre_c2(MacroAssembler* masm,
334 Register obj,
335 Register pre_val,
336 Register tmp,
337 G1PreBarrierStubC2* stub) {
338 const Register thread = r15_thread;
339
340 assert(pre_val != noreg, "check this code");
341 if (obj != noreg) {
342 assert_different_registers(obj, pre_val, tmp);
343 }
344
345 stub->initialize_registers(obj, pre_val, thread, tmp);
346
347 generate_pre_barrier_fast_path(masm, thread);
348 // If marking is active (*(mark queue active address) != 0), jump to stub (slow path)
349 __ jcc(Assembler::notEqual, *stub->entry());
350
351 __ bind(*stub->continuation());
352 }
353
354 void G1BarrierSetAssembler::generate_c2_pre_barrier_stub(MacroAssembler* masm,
355 G1PreBarrierStubC2* stub) const {
356 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
357 Label runtime;
358 Register obj = stub->obj();
359 Register pre_val = stub->pre_val();
360 Register thread = stub->thread();
361 Register tmp = stub->tmp1();
362 assert(stub->tmp2() == noreg, "not needed in this platform");
363
364 __ bind(*stub->entry());
365 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp, *stub->continuation(), runtime);
366
367 __ bind(runtime);
368 generate_c2_barrier_runtime_call(masm, stub, pre_val, CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry));
369 __ jmp(*stub->continuation());
370 }
371
372 void G1BarrierSetAssembler::g1_write_barrier_post_c2(MacroAssembler* masm,
373 Register store_addr,
374 Register new_val,
375 Register tmp,
376 bool new_val_may_be_null) {
377 Label done;
378 generate_post_barrier_fast_path(masm, store_addr, new_val, tmp, done, new_val_may_be_null);
379 __ bind(done);
380 }
381
382 #endif // COMPILER2
383
384 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
385 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
386 bool in_heap = (decorators & IN_HEAP) != 0;
387 bool as_normal = (decorators & AS_NORMAL) != 0;
388
389 bool needs_pre_barrier = as_normal;
390 bool needs_post_barrier = val != noreg && in_heap;
391
392 // flatten object address if needed
393 // We do it regardless of precise because we need the registers
394 if (dst.index() == noreg && dst.disp() == 0) {
395 if (dst.base() != tmp1) {
396 __ movptr(tmp1, dst.base());
397 }
398 } else {
399 __ lea(tmp1, dst);
400 }
401
402 if (needs_pre_barrier) {
403 g1_write_barrier_pre(masm /*masm*/,
404 tmp1 /* obj */,
405 tmp2 /* pre_val */,
406 tmp3 /* tmp */,
407 val != noreg /* tosca_live */,
408 false /* expand_call */);
409 }
410 if (val == noreg) {
411 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp1, 0), val, noreg, noreg, noreg);
412 } else {
413 Register new_val = val;
414 if (needs_post_barrier) {
415 // G1 barrier needs uncompressed oop for region cross check.
416 if (UseCompressedOops) {
417 new_val = tmp2;
418 __ movptr(new_val, val);
419 }
420 }
421 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp1, 0), val, noreg, noreg, noreg);
422 if (needs_post_barrier) {
423 g1_write_barrier_post(masm /*masm*/,
424 tmp1 /* store_adr */,
425 new_val /* new_val */,
426 tmp3 /* tmp */);
427 }
428 }
429 }
430
431 #ifdef COMPILER1
432
433 #undef __
434 #define __ ce->masm()->
435
436 void G1BarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, G1PreBarrierStub* stub) {
437 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
438 // At this point we know that marking is in progress.
439 // If do_load() is true then we have to emit the
440 // load of the previous value; otherwise it has already
441 // been loaded into _pre_val.
442
443 __ bind(*stub->entry());
444 assert(stub->pre_val()->is_register(), "Precondition.");
445
446 Register pre_val_reg = stub->pre_val()->as_register();
447
448 if (stub->do_load()) {
449 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/);
450 }
451
452 __ cmpptr(pre_val_reg, NULL_WORD);
453 __ jcc(Assembler::equal, *stub->continuation());
454 ce->store_parameter(stub->pre_val()->as_register(), 0);
455 __ call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
456 __ jmp(*stub->continuation());
457
458 }
459
460 #undef __
461
462 void G1BarrierSetAssembler::g1_write_barrier_post_c1(MacroAssembler* masm,
463 Register store_addr,
464 Register new_val,
465 Register thread,
466 Register tmp1,
467 Register tmp2 /* unused on x86 */) {
468 Label done;
469 generate_post_barrier_fast_path(masm, store_addr, new_val, tmp1, done, true /* new_val_may_be_null */);
470 masm->bind(done);
471 }
472
473 #define __ sasm->
474
475 void G1BarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
476 // Generated code assumes that buffer index is pointer sized.
477 STATIC_ASSERT(in_bytes(SATBMarkQueue::byte_width_of_index()) == sizeof(intptr_t));
478
479 __ prologue("g1_pre_barrier", false);
480 // arg0 : previous value of memory
481
482 __ push_ppx(rax);
483 __ push_ppx(rdx);
484
485 const Register pre_val = rax;
486 const Register thread = r15_thread;
487 const Register tmp = rdx;
488
489 Address queue_active(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
490 Address queue_index(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()));
491 Address buffer(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()));
492
493 Label done;
494 Label runtime;
495
496 // Is marking still active?
497 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
498 __ cmpl(queue_active, 0);
499 } else {
500 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
501 __ cmpb(queue_active, 0);
502 }
503 __ jcc(Assembler::equal, done);
504
505 // Can we store original value in the thread's buffer?
506
507 __ movptr(tmp, queue_index);
508 __ testptr(tmp, tmp);
509 __ jcc(Assembler::zero, runtime);
510 __ subptr(tmp, wordSize);
511 __ movptr(queue_index, tmp);
512 __ addptr(tmp, buffer);
513
514 // prev_val (rax)
515 __ load_parameter(0, pre_val);
516 __ movptr(Address(tmp, 0), pre_val);
517 __ jmp(done);
518
519 __ bind(runtime);
520
521 __ push_call_clobbered_registers();
522
523 // load the pre-value
524 __ load_parameter(0, rcx);
525 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), rcx, thread);
526
527 __ pop_call_clobbered_registers();
528
529 __ bind(done);
530
531 __ pop_ppx(rdx);
532 __ pop_ppx(rax);
533
534 __ epilogue();
535 }
536
537 #undef __
538
539 #endif // COMPILER1