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 "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 "gc/shared/collectedHeap.hpp"
34 #include "interpreter/interp_masm.hpp"
35 #include "runtime/javaThread.hpp"
36 #include "runtime/sharedRuntime.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 // COMPILER1
42 #ifdef COMPILER2
43 #include "gc/g1/c2/g1BarrierSetC2.hpp"
44 #endif // COMPILER2
45
46 #define __ masm->
47
48 void G1BarrierSetAssembler::gen_write_ref_array_pre_barrier(MacroAssembler* masm, DecoratorSet decorators,
49 Register addr, Register count, RegSet saved_regs) {
50 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
51 if (!dest_uninitialized) {
52 Label done;
53 Address in_progress(rthread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
54
55 // Is marking active?
56 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
57 __ ldrw(rscratch1, in_progress);
58 } else {
59 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
60 __ ldrb(rscratch1, in_progress);
61 }
62 __ cbzw(rscratch1, done);
63
64 __ push(saved_regs, sp);
65 if (count == c_rarg0) {
66 if (addr == c_rarg1) {
67 // exactly backwards!!
68 __ mov(rscratch1, c_rarg0);
69 __ mov(c_rarg0, c_rarg1);
70 __ mov(c_rarg1, rscratch1);
71 } else {
72 __ mov(c_rarg1, count);
73 __ mov(c_rarg0, addr);
74 }
75 } else {
76 __ mov(c_rarg0, addr);
77 __ mov(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(saved_regs, sp);
85
86 __ bind(done);
87 }
88 }
89
90 void G1BarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm,
91 DecoratorSet decorators,
92 Register start,
93 Register count,
94 Register scratch,
95 RegSet saved_regs) {
96
97 Label done;
98 Label loop;
99 Label next;
100
101 __ cbz(count, done);
102
103 // Calculate the number of card marks to set. Since the object might start and
104 // end within a card, we need to calculate this via the card table indexes of
105 // the actual start and last addresses covered by the object.
106 // Temporarily use the count register for the last element address.
107 __ lea(count, Address(start, count, Address::lsl(LogBytesPerHeapOop))); // end = start + count << LogBytesPerHeapOop
108 __ sub(count, count, BytesPerHeapOop); // Use last element address for end.
109
110 __ lsr(start, start, CardTable::card_shift());
111 __ lsr(count, count, CardTable::card_shift());
112 __ sub(count, count, start); // Number of bytes to mark - 1.
113
114 // Add card table base offset to start.
115 __ ldr(scratch, Address(rthread, in_bytes(G1ThreadLocalData::card_table_base_offset())));
116 __ add(start, start, scratch);
117
118 __ bind(loop);
119 if (UseCondCardMark) {
120 __ ldrb(scratch, Address(start, count));
121 // Instead of loading clean_card_val and comparing, we exploit the fact that
122 // the LSB of non-clean cards is always 0, and the LSB of clean cards 1.
123 __ tbz(scratch, 0, next);
124 }
125 static_assert(G1CardTable::dirty_card_val() == 0, "must be to use zr");
126 __ strb(zr, Address(start, count));
127 __ bind(next);
128 __ subs(count, count, 1);
129 __ br(Assembler::GE, loop);
130
131 __ bind(done);
132 }
133
134 static void generate_queue_test_and_insertion(MacroAssembler* masm, ByteSize index_offset, ByteSize buffer_offset, Label& runtime,
135 const Register thread, const Register value, const Register temp1, const Register temp2) {
136 // Can we store a value in the given thread's buffer?
137 // (The index field is typed as size_t.)
138 __ ldr(temp1, Address(thread, in_bytes(index_offset))); // temp1 := *(index address)
139 __ cbz(temp1, runtime); // jump to runtime if index == 0 (full buffer)
140 // The buffer is not full, store value into it.
141 __ sub(temp1, temp1, wordSize); // temp1 := next index
142 __ str(temp1, Address(thread, in_bytes(index_offset))); // *(index address) := next index
143 __ ldr(temp2, Address(thread, in_bytes(buffer_offset))); // temp2 := buffer address
144 __ str(value, Address(temp2, temp1)); // *(buffer address + next index) := value
145 }
146
147 static void generate_pre_barrier_fast_path(MacroAssembler* masm,
148 const Register thread,
149 const Register tmp1) {
150 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
151 // Is marking active?
152 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
153 __ ldrw(tmp1, in_progress);
154 } else {
155 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
156 __ ldrb(tmp1, in_progress);
157 }
158 }
159
160 static void generate_pre_barrier_slow_path(MacroAssembler* masm,
161 const Register obj,
162 const Register pre_val,
163 const Register thread,
164 const Register tmp1,
165 const Register tmp2,
166 Label& done,
167 Label& runtime) {
168 // Do we need to load the previous value?
169 if (obj != noreg) {
170 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
171 }
172 // Is the previous value null?
173 __ cbz(pre_val, done);
174 generate_queue_test_and_insertion(masm,
175 G1ThreadLocalData::satb_mark_queue_index_offset(),
176 G1ThreadLocalData::satb_mark_queue_buffer_offset(),
177 runtime,
178 thread, pre_val, tmp1, tmp2);
179 __ b(done);
180 }
181
182 void G1BarrierSetAssembler::g1_write_barrier_pre(MacroAssembler* masm,
183 Register obj,
184 Register pre_val,
185 Register thread,
186 Register tmp1,
187 Register tmp2,
188 bool tosca_live,
189 bool expand_call) {
190 // If expand_call is true then we expand the call_VM_leaf macro
191 // directly to skip generating the check by
192 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
193
194 assert(thread == rthread, "must be");
195
196 Label done;
197 Label runtime;
198
199 assert_different_registers(obj, pre_val, tmp1, tmp2);
200 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
201
202 generate_pre_barrier_fast_path(masm, thread, tmp1);
203 // If marking is not active (*(mark queue active address) == 0), jump to done
204 __ cbzw(tmp1, done);
205 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp1, tmp2, done, runtime);
206
207 __ bind(runtime);
208
209 __ push_call_clobbered_registers();
210
211 // Calling the runtime using the regular call_VM_leaf mechanism generates
212 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
213 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == nullptr.
214 //
215 // If we care generating the pre-barrier without a frame (e.g. in the
216 // intrinsified Reference.get() routine) then rfp might be pointing to
217 // the caller frame and so this check will most likely fail at runtime.
218 //
219 // Expanding the call directly bypasses the generation of the check.
220 // So when we do not have have a full interpreter frame on the stack
221 // expand_call should be passed true.
222
223 if (expand_call) {
224 assert(pre_val != c_rarg1, "smashed arg");
225 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
226 } else {
227 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
228 }
229
230 __ pop_call_clobbered_registers();
231
232 __ bind(done);
233
234 }
235
236 static void generate_post_barrier_fast_path(MacroAssembler* masm,
237 const Register store_addr,
238 const Register new_val,
239 const Register thread,
240 const Register tmp1,
241 const Register tmp2,
242 Label& done,
243 bool new_val_may_be_null) {
244 assert(thread == rthread, "must be");
245 assert_different_registers(store_addr, new_val, thread, tmp1, tmp2, noreg, rscratch1);
246
247 // Does store cross heap regions?
248 #if INCLUDE_CDS
249 // AOT code needs to load the barrier grain shift from the aot
250 // runtime constants area in the code cache otherwise we can compile
251 // it as an immediate operand
252 if (AOTCodeCache::is_on_for_dump()) {
253 address grain_shift_address = (address)AOTRuntimeConstants::grain_shift_address();
254 __ eor(tmp1, store_addr, new_val);
255 __ lea(tmp2, ExternalAddress(grain_shift_address));
256 __ ldrb(tmp2, tmp2);
257 __ lsrv(tmp1, tmp1, tmp2);
258 __ cbz(tmp1, done);
259 } else
260 #endif
261 {
262 __ eor(tmp1, store_addr, new_val); // tmp1 := store address ^ new value
263 __ lsr(tmp1, tmp1, G1HeapRegion::LogOfHRGrainBytes); // tmp1 := ((store address ^ new value) >> LogOfHRGrainBytes)
264 __ cbz(tmp1, done);
265 }
266
267 // Crosses regions, storing null?
268 if (new_val_may_be_null) {
269 __ cbz(new_val, done);
270 }
271 // Storing region crossing non-null.
272 __ lsr(tmp1, store_addr, CardTable::card_shift()); // tmp1 := card address relative to card table base
273
274 Address card_table_addr(thread, in_bytes(G1ThreadLocalData::card_table_base_offset()));
275 __ ldr(tmp2, card_table_addr); // tmp2 := card table base address
276 if (UseCondCardMark) {
277 __ ldrb(rscratch1, Address(tmp1, tmp2)); // rscratch1 := card
278 // Instead of loading clean_card_val and comparing, we exploit the fact that
279 // the LSB of non-clean cards is always 0, and the LSB of clean cards 1.
280 __ tbz(rscratch1, 0, done);
281 }
282 static_assert(G1CardTable::dirty_card_val() == 0, "must be to use zr");
283 __ strb(zr, Address(tmp1, tmp2)); // *(card address) := dirty_card_val
284 }
285
286 void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm,
287 Register store_addr,
288 Register new_val,
289 Register thread,
290 Register tmp1,
291 Register tmp2) {
292 Label done;
293 generate_post_barrier_fast_path(masm, store_addr, new_val, thread, tmp1, tmp2, done, false /* new_val_may_be_null */);
294 __ bind(done);
295 }
296
297 #if defined(COMPILER2)
298
299 static void generate_c2_barrier_runtime_call(MacroAssembler* masm, G1BarrierStubC2* stub, const Register arg, const address runtime_path) {
300 SaveLiveRegisters save_registers(masm, stub);
301 if (c_rarg0 != arg) {
302 __ mov(c_rarg0, arg);
303 }
304 __ mov(c_rarg1, rthread);
305 __ lea(rscratch1, RuntimeAddress(runtime_path));
306 __ blr(rscratch1);
307 }
308
309 void G1BarrierSetAssembler::g1_write_barrier_pre_c2(MacroAssembler* masm,
310 Register obj,
311 Register pre_val,
312 Register thread,
313 Register tmp1,
314 Register tmp2,
315 G1PreBarrierStubC2* stub) {
316 assert(thread == rthread, "must be");
317 assert_different_registers(obj, pre_val, tmp1, tmp2);
318 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
319
320 stub->initialize_registers(obj, pre_val, thread, tmp1, tmp2);
321
322 generate_pre_barrier_fast_path(masm, thread, tmp1);
323 // If marking is active (*(mark queue active address) != 0), jump to stub (slow path)
324 __ cbnzw(tmp1, *stub->entry());
325
326 __ bind(*stub->continuation());
327 }
328
329 void G1BarrierSetAssembler::generate_c2_pre_barrier_stub(MacroAssembler* masm,
330 G1PreBarrierStubC2* stub) const {
331 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
332 Label runtime;
333 Register obj = stub->obj();
334 Register pre_val = stub->pre_val();
335 Register thread = stub->thread();
336 Register tmp1 = stub->tmp1();
337 Register tmp2 = stub->tmp2();
338
339 __ bind(*stub->entry());
340 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp1, tmp2, *stub->continuation(), runtime);
341
342 __ bind(runtime);
343 generate_c2_barrier_runtime_call(masm, stub, pre_val, CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry));
344 __ b(*stub->continuation());
345 }
346
347 void G1BarrierSetAssembler::g1_write_barrier_post_c2(MacroAssembler* masm,
348 Register store_addr,
349 Register new_val,
350 Register thread,
351 Register tmp1,
352 Register tmp2,
353 bool new_val_may_be_null) {
354 Label done;
355 generate_post_barrier_fast_path(masm, store_addr, new_val, thread, tmp1, tmp2, done, new_val_may_be_null);
356 __ bind(done);
357 }
358
359 #endif // COMPILER2
360
361 void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
362 Register dst, Address src, Register tmp1, Register tmp2) {
363 bool on_oop = is_reference_type(type);
364 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
365 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
366 bool on_reference = on_weak || on_phantom;
367 ModRefBarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
368 if (on_oop && on_reference) {
369 // LR is live. It must be saved around calls.
370 __ enter(/*strip_ret_addr*/true); // barrier may call runtime
371 // Generate the G1 pre-barrier code to log the value of
372 // the referent field in an SATB buffer.
373 g1_write_barrier_pre(masm /* masm */,
374 noreg /* obj */,
375 dst /* pre_val */,
376 rthread /* thread */,
377 tmp1 /* tmp1 */,
378 tmp2 /* tmp2 */,
379 true /* tosca_live */,
380 true /* expand_call */);
381 __ leave();
382 }
383 }
384
385 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
386 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
387 // flatten object address if needed
388 if (dst.index() == noreg && dst.offset() == 0) {
389 if (dst.base() != tmp3) {
390 __ mov(tmp3, dst.base());
391 }
392 } else {
393 __ lea(tmp3, dst);
394 }
395
396 g1_write_barrier_pre(masm,
397 tmp3 /* obj */,
398 tmp2 /* pre_val */,
399 rthread /* thread */,
400 tmp1 /* tmp1 */,
401 rscratch2 /* tmp2 */,
402 val != noreg /* tosca_live */,
403 false /* expand_call */);
404
405 if (val == noreg) {
406 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), noreg, noreg, noreg, noreg);
407 } else {
408 // G1 barrier needs uncompressed oop for region cross check.
409 Register new_val = val;
410 if (UseCompressedOops) {
411 new_val = rscratch2;
412 __ mov(new_val, val);
413 }
414 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), val, noreg, noreg, noreg);
415 g1_write_barrier_post(masm,
416 tmp3 /* store_adr */,
417 new_val /* new_val */,
418 rthread /* thread */,
419 tmp1 /* tmp1 */,
420 tmp2 /* tmp2 */);
421 }
422
423 }
424
425 #ifdef COMPILER1
426
427 #undef __
428 #define __ ce->masm()->
429
430 void G1BarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, G1PreBarrierStub* stub) {
431 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
432 // At this point we know that marking is in progress.
433 // If do_load() is true then we have to emit the
434 // load of the previous value; otherwise it has already
435 // been loaded into _pre_val.
436
437 __ bind(*stub->entry());
438
439 assert(stub->pre_val()->is_register(), "Precondition.");
440
441 Register pre_val_reg = stub->pre_val()->as_register();
442
443 if (stub->do_load()) {
444 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/);
445 }
446 __ cbz(pre_val_reg, *stub->continuation());
447 ce->store_parameter(stub->pre_val()->as_register(), 0);
448 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
449 __ b(*stub->continuation());
450 }
451
452 #undef __
453
454 void G1BarrierSetAssembler::g1_write_barrier_post_c1(MacroAssembler* masm,
455 Register store_addr,
456 Register new_val,
457 Register thread,
458 Register tmp1,
459 Register tmp2) {
460 Label done;
461 generate_post_barrier_fast_path(masm, store_addr, new_val, thread, tmp1, tmp2, done, true /* new_val_may_be_null */);
462 masm->bind(done);
463 }
464
465 #define __ sasm->
466
467 void G1BarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
468 __ prologue("g1_pre_barrier", false);
469
470 // arg0 : previous value of memory
471
472 BarrierSet* bs = BarrierSet::barrier_set();
473
474 const Register pre_val = r0;
475 const Register thread = rthread;
476 const Register tmp = rscratch1;
477
478 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
479 Address queue_index(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()));
480 Address buffer(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()));
481
482 Label done;
483 Label runtime;
484
485 // Is marking still active?
486 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
487 __ ldrw(tmp, in_progress);
488 } else {
489 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
490 __ ldrb(tmp, in_progress);
491 }
492 __ cbzw(tmp, done);
493
494 // Can we store original value in the thread's buffer?
495 __ ldr(tmp, queue_index);
496 __ cbz(tmp, runtime);
497
498 __ sub(tmp, tmp, wordSize);
499 __ str(tmp, queue_index);
500 __ ldr(rscratch2, buffer);
501 __ add(tmp, tmp, rscratch2);
502 __ load_parameter(0, rscratch2);
503 __ str(rscratch2, Address(tmp, 0));
504 __ b(done);
505
506 __ bind(runtime);
507 __ push_call_clobbered_registers();
508 __ load_parameter(0, pre_val);
509 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
510 __ pop_call_clobbered_registers();
511 __ bind(done);
512
513 __ epilogue();
514 }
515
516 #undef __
517
518 #endif // COMPILER1