1 /*
2 * Copyright (c) 2026, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2018, 2020, Red Hat, Inc. All rights reserved.
4 * Copyright (c) 2020, 2021, Huawei Technologies Co., Ltd. All rights reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
28 #include "gc/shenandoah/mode/shenandoahMode.hpp"
29 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
30 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
33 #include "gc/shenandoah/shenandoahRuntime.hpp"
34 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
35 #include "interpreter/interp_masm.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "runtime/javaThread.hpp"
38 #include "runtime/sharedRuntime.hpp"
39 #ifdef COMPILER1
40 #include "c1/c1_LIRAssembler.hpp"
41 #include "c1/c1_MacroAssembler.hpp"
42 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
43 #endif
44 #ifdef COMPILER2
45 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
46 #include "opto/output.hpp"
47 #endif
48
49 #define __ masm->
50
51 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
52 Register src, Register dst, Register count, RegSet saved_regs) {
53 if (is_oop) {
54 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
55 if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) {
56
57 Label done;
58
59 // Avoid calling runtime if count == 0
60 __ beqz(count, done);
61
62 // Is GC active?
63 Address gc_state(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
64 assert_different_registers(src, dst, count, t0);
65
66 assert(!saved_regs.contains(t0), "Sanity: about to clobber t0");
67
68 __ lbu(t0, gc_state);
69 if (ShenandoahSATBBarrier && dest_uninitialized) {
70 __ test_bit(t0, t0, ShenandoahHeap::HAS_FORWARDED_BITPOS);
71 __ beqz(t0, done);
72 } else {
73 __ andi(t0, t0, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING);
74 __ beqz(t0, done);
75 }
76
77 __ push_call_clobbered_registers();
78 // If arguments are not in proper places, shuffle them.
79 // Doing this via the stack is the most straight-forward way to avoid
80 // accidentally smashing any register.
81 if (c_rarg0 != src || c_rarg1 != dst || c_rarg2 != count) {
82 __ push_reg(RegSet::of(src), sp);
83 __ push_reg(RegSet::of(dst), sp);
84 __ push_reg(RegSet::of(count), sp);
85 __ pop_reg(RegSet::of(c_rarg2), sp);
86 __ pop_reg(RegSet::of(c_rarg1), sp);
87 __ pop_reg(RegSet::of(c_rarg0), sp);
88 }
89 address target = nullptr;
90 if (UseCompressedOops) {
91 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_narrow_oop);
92 } else {
93 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_oop);
94 }
95 __ call_VM_leaf(target, 3);
96 __ pop_call_clobbered_registers();
97 __ bind(done);
98 }
99 }
100 }
101
102 void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
103 Register start, Register count, Register tmp) {
104 if (ShenandoahCardBarrier && is_oop) {
105 gen_write_ref_array_post_barrier(masm, decorators, start, count, tmp);
106 }
107 }
108
109 void ShenandoahBarrierSetAssembler::satb_barrier(MacroAssembler* masm,
110 Register obj,
111 Register pre_val,
112 Register thread,
113 Register tmp1,
114 Register tmp2) {
115 assert(ShenandoahSATBBarrier, "Should be checked by caller");
116 assert(thread == xthread, "must be");
117
118 Label done;
119 Label runtime;
120
121 assert_different_registers(obj, pre_val, tmp1, tmp2);
122 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
123
124 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
125 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
126
127 // Is marking active?
128 Address gc_state(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
129 __ lbu(t1, gc_state);
130 __ test_bit(t1, t1, ShenandoahHeap::MARKING_BITPOS);
131 __ beqz(t1, done);
132
133 // Do we need to load the previous value?
134 if (obj != noreg) {
135 if (UseCompressedOops) {
136 __ lwu(pre_val, Address(obj, 0));
137 __ decode_heap_oop(pre_val);
138 } else {
139 __ ld(pre_val, Address(obj, 0));
140 }
141 }
142
143 // Is the previous value null?
144 __ beqz(pre_val, done);
145
146 // Can we store original value in the thread's buffer?
147 // Is index == 0?
148 // (The index field is typed as size_t.)
149 __ ld(tmp1, index); // tmp := *index_adr
150 __ beqz(tmp1, runtime); // tmp == 0? If yes, goto runtime
151
152 __ subi(tmp1, tmp1, wordSize); // tmp := tmp - wordSize
153 __ sd(tmp1, index); // *index_adr := tmp
154 __ ld(tmp2, buffer);
155 __ add(tmp1, tmp1, tmp2); // tmp := tmp + *buffer_adr
156
157 // Record the previous value
158 __ sd(pre_val, Address(tmp1, 0));
159 __ j(done);
160
161 // Slow-path call.
162 __ bind(runtime);
163 __ enter();
164 __ push_call_clobbered_registers();
165 if (c_rarg0 != pre_val) {
166 __ mv(c_rarg0, pre_val);
167 }
168 // Calling with super_call_VM_leaf with c_rarg0 bypasses interpreter checks and avoids any moves.
169 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), c_rarg0);
170 __ pop_call_clobbered_registers();
171 __ leave();
172
173 __ bind(done);
174 }
175
176 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm,
177 Register dst,
178 Address load_addr,
179 DecoratorSet decorators) {
180 assert(ShenandoahLoadRefBarrier, "Should be enabled");
181 assert(dst != t1 && load_addr.base() != t1, "need t1");
182 assert_different_registers(load_addr.base(), t0, t1);
183
184 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
185 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
186 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
187 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
188 bool is_narrow = UseCompressedOops && !is_native;
189
190 Label heap_stable, not_cset;
191 Address gc_state(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
192 __ lbu(t1, gc_state);
193
194 // Check for heap stability
195 if (is_strong) {
196 __ test_bit(t1, t1, ShenandoahHeap::HAS_FORWARDED_BITPOS);
197 __ beqz(t1, heap_stable);
198 } else {
199 Label lrb;
200 __ test_bit(t0, t1, ShenandoahHeap::WEAK_ROOTS_BITPOS);
201 __ bnez(t0, lrb);
202 __ test_bit(t0, t1, ShenandoahHeap::HAS_FORWARDED_BITPOS);
203 __ beqz(t0, heap_stable);
204 __ bind(lrb);
205 }
206
207 // use x11 for load address
208 Register result_dst = dst;
209 if (dst == x11) {
210 __ mv(t1, dst);
211 dst = t1;
212 }
213
214 // Save x10 and x11, unless it is an output register
215 RegSet saved_regs = RegSet::of(x10, x11) - result_dst;
216 __ push_reg(saved_regs, sp);
217 __ la(x11, load_addr);
218 __ mv(x10, dst);
219
220 // Test for in-cset
221 if (is_strong) {
222 if (AOTCodeCache::is_on_for_dump()) {
223 __ ld(t1, ExternalAddress(AOTRuntimeConstants::cset_base_address()));
224 __ lwu(t0, ExternalAddress(AOTRuntimeConstants::grain_shift_address()));
225 __ srl(t0, x10, t0);
226 } else {
227 __ mv(t1, ShenandoahHeap::in_cset_fast_test_addr());
228 __ srli(t0, x10, ShenandoahHeapRegion::region_size_bytes_shift_jint());
229 }
230 __ add(t1, t1, t0);
231 __ lbu(t1, Address(t1));
232 __ test_bit(t0, t1, 0);
233 __ beqz(t0, not_cset);
234 }
235
236 // Slow-path call
237 __ enter();
238 __ push_call_clobbered_registers();
239 address target = nullptr;
240 if (is_strong) {
241 if (is_narrow) {
242 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow);
243 } else {
244 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong);
245 }
246 } else if (is_weak) {
247 if (is_narrow) {
248 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow);
249 } else {
250 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak);
251 }
252 } else {
253 assert(is_phantom, "only remaining strength");
254 assert(!is_narrow, "phantom access cannot be narrow");
255 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom);
256 }
257 // Calling with super_call_VM_leaf with c_rarg0/1 bypasses interpreter checks and avoids any moves.
258 __ super_call_VM_leaf(target, c_rarg0, c_rarg1);
259 __ mv(t0, x10);
260 __ pop_call_clobbered_registers();
261 __ mv(x10, t0);
262 __ leave();
263
264 __ bind(not_cset);
265 __ mv(result_dst, x10);
266 __ pop_reg(saved_regs, sp);
267
268 __ bind(heap_stable);
269 }
270
271 //
272 // Arguments:
273 //
274 // Inputs:
275 // src: oop location to load from, might be clobbered
276 //
277 // Output:
278 // dst: oop loaded from src location
279 //
280 // Kill:
281 // x30 (tmp reg)
282 //
283 // Alias:
284 // dst: x30 (might use x30 as temporary output register to avoid clobbering src)
285 //
286 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm,
287 DecoratorSet decorators,
288 BasicType type,
289 Register dst,
290 Address src,
291 Register tmp1,
292 Register tmp2) {
293 // 1: non-reference load, no additional barrier is needed
294 if (!is_reference_type(type)) {
295 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
296 return;
297 }
298
299 // 2: load a reference from src location and apply LRB if needed
300 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
301 Register result_dst = dst;
302
303 // Preserve src location for LRB
304 RegSet saved_regs;
305 if (dst == src.base()) {
306 dst = (src.base() == x28) ? x29 : x28;
307 saved_regs = RegSet::of(dst);
308 __ push_reg(saved_regs, sp);
309 }
310 assert_different_registers(dst, src.base());
311
312 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
313
314 load_reference_barrier(masm, dst, src, decorators);
315
316 if (dst != result_dst) {
317 __ mv(result_dst, dst);
318 dst = result_dst;
319 }
320
321 if (saved_regs.bits() != 0) {
322 __ pop_reg(saved_regs, sp);
323 }
324 } else {
325 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
326 }
327
328 // 3: apply keep-alive barrier if needed
329 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
330 satb_barrier(masm /* masm */,
331 noreg /* obj */,
332 dst /* pre_val */,
333 xthread /* thread */,
334 tmp1 /* tmp1 */,
335 tmp2 /* tmp2 */);
336 }
337 }
338
339 void ShenandoahBarrierSetAssembler::card_barrier(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2) {
340 assert(ShenandoahCardBarrier, "Should have been checked by caller");
341 assert(CardTable::dirty_card_val() == 0, "must be");
342 assert_different_registers(obj, tmp1, tmp2);
343
344 __ srli(obj, obj, CardTable::card_shift());
345
346 Address curr_ct_holder_addr(xthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
347 __ ld(tmp1, curr_ct_holder_addr);
348 __ add(tmp1, obj, tmp1);
349
350 if (UseCondCardMark) {
351 Label L_already_dirty;
352 __ lbu(tmp2, Address(tmp1));
353 __ beqz(tmp2, L_already_dirty);
354 __ sb(zr, Address(tmp1));
355 __ bind(L_already_dirty);
356 } else {
357 __ sb(zr, Address(tmp1));
358 }
359 }
360
361 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
362 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
363 // 1: non-reference types require no barriers
364 if (!is_reference_type(type)) {
365 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2, tmp3);
366 return;
367 }
368
369 // Flatten object address right away for simplicity: likely needed by barriers
370 if (dst.offset() == 0) {
371 if (dst.base() != tmp3) {
372 __ mv(tmp3, dst.base());
373 }
374 } else {
375 __ la(tmp3, dst);
376 }
377
378 // 2: pre-barrier: SATB needs the previous value
379 if (ShenandoahBarrierSet::need_satb_barrier(decorators, type)) {
380 satb_barrier(masm,
381 tmp3 /* obj */,
382 tmp2 /* pre_val */,
383 xthread /* thread */,
384 tmp1 /* tmp */,
385 t0 /* tmp2 */);
386 }
387
388 // Store!
389 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), val, noreg, noreg, noreg);
390
391 // 3: post-barrier: card barrier needs store address
392 bool storing_non_null = (val != noreg);
393 if (ShenandoahBarrierSet::need_card_barrier(decorators, type) && storing_non_null) {
394 card_barrier(masm, tmp3, tmp1, tmp2);
395 }
396 }
397
398 void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
399 Register obj, Register tmp, Label& slowpath) {
400 Label done;
401 // Resolve jobject
402 BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath);
403
404 // Check for null.
405 __ beqz(obj, done);
406
407 assert(obj != t1, "need t1");
408 Address gc_state(jni_env, ShenandoahThreadLocalData::gc_state_offset() - JavaThread::jni_environment_offset());
409 __ lbu(t1, gc_state);
410
411 // Check for heap in evacuation phase
412 __ test_bit(t0, t1, ShenandoahHeap::EVACUATION_BITPOS);
413 __ bnez(t0, slowpath);
414
415 __ bind(done);
416 }
417
418 void ShenandoahBarrierSetAssembler::try_peek_weak_handle_in_nmethod(MacroAssembler *masm, Register weak_handle,
419 Register obj, Register tmp, Label& slow_path) {
420 assert_different_registers(weak_handle, tmp, noreg);
421 assert_different_registers(obj, tmp, noreg);
422
423
424 Label done;
425
426 // Peek weak handle using the standard implementation.
427 BarrierSetAssembler::try_peek_weak_handle_in_nmethod(masm, weak_handle, obj, tmp, slow_path);
428
429 // Check if the reference is null, and if it is, take the fast path.
430 __ beqz(obj, done);
431
432 Address gc_state(xthread, ShenandoahThreadLocalData::gc_state_offset());
433 __ lbu(tmp, gc_state);
434
435 // Check if the heap is under weak-reference/roots processing, in
436 // which case we need to take the slow path.
437 __ test_bit(tmp, tmp, ShenandoahHeap::WEAK_ROOTS_BITPOS);
438 __ bnez(tmp, slow_path);
439 __ bind(done);
440 }
441
442 void ShenandoahBarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& L_error) {
443 // Check if the oop is in the right area of memory
444 __ mv(tmp2, (intptr_t) Universe::verify_oop_mask());
445 __ andr(tmp1, obj, tmp2);
446 __ mv(tmp2, (intptr_t) Universe::verify_oop_bits());
447
448 // Compare tmp1 and tmp2.
449 __ bne(tmp1, tmp2, L_error);
450
451 // This routine is sometimes called before applying GC barriers.
452 // With +COH, loading the klass may end up loading forwarding pointer instead.
453 Label L_skip;
454 if (UseCompactObjectHeaders) {
455 Address gc_state(xthread, ShenandoahThreadLocalData::gc_state_offset());
456 __ lbu(tmp1, gc_state);
457 __ test_bit(tmp1, tmp1, ShenandoahHeap::HAS_FORWARDED_BITPOS);
458 __ bnez(tmp1, L_skip);
459 }
460
461 // Make sure klass is 'reasonable', which is not zero.
462 __ load_narrow_klass(tmp1, obj);
463 __ beqz(tmp1, L_error);
464
465 __ bind(L_skip);
466 }
467
468 void ShenandoahBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
469 Register start, Register count, Register tmp) {
470 assert(ShenandoahCardBarrier, "Did you mean to enable ShenandoahCardBarrier?");
471
472 Label L_loop, L_done;
473 const Register end = count;
474
475 // Zero count? Nothing to do.
476 __ beqz(count, L_done);
477
478 // end = start + count << LogBytesPerHeapOop
479 // last element address to make inclusive
480 __ shadd(end, count, start, tmp, LogBytesPerHeapOop);
481 __ subi(end, end, BytesPerHeapOop);
482 __ srli(start, start, CardTable::card_shift());
483 __ srli(end, end, CardTable::card_shift());
484
485 // number of bytes to copy
486 __ sub(count, end, start);
487
488 Address curr_ct_holder_addr(xthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
489 __ ld(tmp, curr_ct_holder_addr);
490 __ add(start, start, tmp);
491
492 __ bind(L_loop);
493 __ add(tmp, start, count);
494 __ sb(zr, Address(tmp));
495 __ subi(count, count, 1);
496 __ bgez(count, L_loop);
497 __ bind(L_done);
498 }
499
500 #undef __
501
502 #ifdef COMPILER1
503
504 #define __ ce->masm()->
505
506 void ShenandoahBarrierSetAssembler::keepalive_barrier_c1_stub(LIR_Assembler* ce, ShenandoahKeepaliveBarrierStub* stub) {
507 __ bind(*stub->entry());
508
509 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
510
511 Register obj = stub->obj()->as_register();
512
513 if (stub->do_load()) {
514 ce->mem2reg(stub->addr(), stub->obj(), T_OBJECT, lir_patch_none, nullptr, false /* wide */);
515 }
516 __ beqz(obj, *stub->continuation(), /* is_far */ true);
517
518 ce->store_parameter(obj, 0);
519 __ far_call(RuntimeAddress(bs->keepalive_barrier_stub()));
520 __ j(*stub->continuation());
521 }
522
523 void ShenandoahBarrierSetAssembler::load_reference_barrier_c1_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
524 __ bind(*stub->entry());
525
526 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*) BarrierSet::barrier_set()->barrier_set_c1();
527
528 Register obj = stub->obj()->as_register();
529 Register addr = stub->addr()->as_pointer_register();
530 Register slow_result = stub->slow_result()->as_register();
531 assert_different_registers(obj, addr, slow_result);
532 assert(slow_result == x10, "C1 must know about our slow call result register");
533
534 ce->store_parameter(obj, 0);
535 ce->store_parameter(addr, 1);
536 __ far_call(RuntimeAddress(bs->load_reference_barrier_stub(stub->decorators())));
537 if (obj != slow_result) {
538 __ mv(obj, slow_result);
539 }
540
541 __ j(*stub->continuation());
542 }
543
544 #undef __
545
546 #define __ sasm->
547
548 void ShenandoahBarrierSetAssembler::keepalive_barrier_c1_runtime_stub(StubAssembler* sasm) {
549 __ prologue("shenandoah_keepalive_barrier", false);
550 const Register tmp_obj = x10;
551 const Register tmp1 = x11;
552 const Register tmp2 = x12;
553 __ push_reg(RegSet::of(tmp1, tmp2, tmp_obj), sp);
554 __ load_parameter(0, tmp_obj);
555 satb_barrier(sasm, noreg, tmp_obj, xthread, tmp1, tmp2);
556 __ pop_reg(RegSet::of(tmp1, tmp2, tmp_obj), sp);
557 __ epilogue();
558 }
559
560 void ShenandoahBarrierSetAssembler::load_reference_barrier_c1_runtime_stub(StubAssembler* sasm, DecoratorSet decorators) {
561 __ prologue("shenandoah_load_reference_barrier", false);
562 const Register tmp_obj = x10;
563 const Register tmp_addr = x11;
564 __ push_reg(RegSet::of(tmp_addr), sp);
565 __ load_parameter(0, tmp_obj);
566 __ load_parameter(1, tmp_addr);
567 load_reference_barrier(sasm, tmp_obj, Address(tmp_addr, 0), decorators);
568 __ pop_reg(RegSet::of(tmp_addr), sp);
569 __ epilogue();
570 }
571
572 #undef __
573
574 #endif // COMPILER1
575
576 #ifdef COMPILER2
577
578 #undef __
579 #define __ masm->
580
581 void ShenandoahBarrierSetAssembler::load_c2(const MachNode* node, MacroAssembler* masm, Register dst, Address src, Register tmp1, Register tmp2, bool is_narrow) {
582 // Do the actual load. This load is the candidate for implicit null check, and MUST come first.
583 if (is_narrow) {
584 __ lwu(dst, src);
585 } else {
586 __ ld(dst, src);
587 }
588
589 ShenandoahBarrierStubC2::load_post(masm, node, dst, src, tmp1, tmp2, is_narrow);
590 }
591
592 void ShenandoahBarrierSetAssembler::store_c2(const MachNode* node, MacroAssembler* masm, Address dst, bool dst_narrow,
593 Register src, bool src_narrow, Register tmp1, Register tmp2, Register tmp3) {
594
595 ShenandoahBarrierStubC2::store_pre(masm, node, dst, tmp1, tmp2, tmp3, dst_narrow);
596
597 // Do the actual store
598 if (dst_narrow) {
599 if (!src_narrow) {
600 // Need to encode into tmp, because we cannot clobber src.
601 assert(tmp1 != noreg, "need temp register");
602 if ((node->barrier_data() & ShenandoahBitNotNull) == 0) {
603 __ encode_heap_oop(tmp1, src);
604 } else {
605 __ encode_heap_oop_not_null(tmp1, src);
606 }
607 src = tmp1;
608 }
609 __ sw(src, dst);
610 } else {
611 __ sd(src, dst);
612 }
613
614 ShenandoahBarrierStubC2::store_post(masm, node, dst, tmp2, tmp3);
615 }
616
617 void ShenandoahBarrierSetAssembler::compare_and_set_c2(const MachNode* node, MacroAssembler* masm, Register res, Register addr,
618 Register oldval, Register newval, Register tmp1, Register tmp2, Register tmp3, bool exchange, bool narrow, bool is_acquire) {
619 const Assembler::Aqrl acquire = is_acquire ? Assembler::aq : Assembler::relaxed;
620 const Assembler::Aqrl release = Assembler::rl;
621 const Assembler::operand_size size = narrow ? Assembler::uint32 : Assembler::int64;
622
623 ShenandoahBarrierStubC2::load_store_pre(masm, node, Address(addr), tmp1, tmp2, tmp3, narrow);
624
625 // CAS!
626 __ cmpxchg(addr, oldval, newval, size, acquire, release, /* result */ res, !exchange /* result_as_bool */);
627
628 ShenandoahBarrierStubC2::load_store_post(masm, node, Address(addr, 0), tmp2, tmp3);
629 }
630
631 void ShenandoahBarrierSetAssembler::get_and_set_c2(const MachNode* node, MacroAssembler* masm, Register preval,
632 Register newval, Register addr, Register tmp1, Register tmp2, Register tmp3, bool is_acquire) {
633 const bool is_narrow = node->bottom_type()->isa_narrowoop();
634
635 ShenandoahBarrierStubC2::load_store_pre(masm, node, Address(addr, 0), tmp1, tmp2, tmp3, is_narrow);
636
637 if (is_narrow) {
638 if (is_acquire) {
639 __ atomic_xchgalwu(preval, newval, addr);
640 } else {
641 __ atomic_xchgwu(preval, newval, addr);
642 }
643 } else {
644 if (is_acquire) {
645 __ atomic_xchgal(preval, newval, addr);
646 } else {
647 __ atomic_xchg(preval, newval, addr);
648 }
649 }
650
651 ShenandoahBarrierStubC2::load_store_post(masm, node, Address(addr, 0), tmp2, tmp3);
652 }
653
654 #undef __
655 #define __ masm.
656
657 void ShenandoahBarrierStubC2::cardtable(MacroAssembler& masm, Address address, Register tmp1, Register tmp2) {
658 assert(CardTable::dirty_card_val() == 0, "must be");
659 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
660
661 // tmp1 = card table base (holder)
662 Address curr_ct_holder_addr(xthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
663 __ ld(tmp1, curr_ct_holder_addr);
664
665 // tmp1 = effective address
666 __ la(tmp2, address);
667
668 // tmp2 = &card_table[ addr >> CardTable::card_shift() ] ; card index
669 __ srli(tmp2, tmp2, CardTable::card_shift());
670 __ add(tmp2, tmp2, tmp1);
671
672 if (UseCondCardMark) {
673 Label L_already_dirty;
674 __ lbu(tmp1, Address(tmp2));
675 __ beqz(tmp1, L_already_dirty);
676 __ sb(zr, Address(tmp2));
677 __ bind(L_already_dirty);
678 } else {
679 __ sb(zr, Address(tmp2));
680 }
681 }
682
683 void ShenandoahBarrierStubC2::enter_if_gc_state(MacroAssembler& masm, const char test_state, Register tmp) {
684 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
685
686 Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(test_state)));
687 __ lbu(tmp, gc_state_fast);
688 __ beqz(tmp, *continuation());
689 __ j(*entry());
690
691 // This is were the slowpath stub will return to or the code above will
692 // jump to if the checks are false
693 __ bind(*continuation());
694 }
695
696 void ShenandoahBarrierStubC2::emit_code(MacroAssembler& masm) {
697 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
698 assert(_needs_keep_alive_barrier || _needs_load_ref_barrier, "Why are you here?");
699
700 __ bind(*entry());
701
702 // If we need to load ourselves, do it here.
703 if (_do_load) {
704 if (_narrow) {
705 __ lwu(_obj, _addr);
706 } else {
707 __ ld(_obj, _addr);
708 }
709 }
710
711 // If the object is null, there is no point in applying barriers.
712 maybe_far_jump_if_zero(masm, _obj);
713
714 // We need to make sure that loads done by callers survive across slow-path calls.
715 // For self-loads, we need to care about the case when both KA and LRB are enabled (rare).
716 bool needs_both_barriers = _needs_keep_alive_barrier && _needs_load_ref_barrier;
717 if (!_do_load || needs_both_barriers) {
718 preserve(_obj);
719 }
720
721 // Go for barriers. Barriers can return straight to continuation, as long
722 // as another barrier is not needed and we can reach the fastpath.
723 if (needs_both_barriers) {
724 keepalive(masm, nullptr);
725 lrb(masm);
726 } else if (_needs_keep_alive_barrier) {
727 keepalive(masm, continuation());
728 } else if (_needs_load_ref_barrier) {
729 lrb(masm);
730 } else {
731 ShouldNotReachHere();
732 }
733 }
734
735 void ShenandoahBarrierStubC2::maybe_far_jump_if_zero(MacroAssembler& masm, Register reg) {
736 Label L_short_jump;
737 __ bnez(reg, L_short_jump);
738 __ j(*continuation());
739 __ bind(L_short_jump);
740 }
741
742 void ShenandoahBarrierStubC2::keepalive(MacroAssembler& masm, Label* L_done) {
743 Address index(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
744 Address buffer(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
745 Label L_through, L_slowpath;
746
747 // If another barrier is enabled as well, do a runtime check for a specific barrier.
748 if (_needs_load_ref_barrier) {
749 assert(L_done == nullptr, "L_done is always null when _needs_load_ref_barrier is true");
750 Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::MARKING)));
751 __ lbu(_tmp1, gc_state_fast);
752 __ beqz(_tmp1, L_through);
753 }
754
755 // Fast-path: put object into buffer.
756 // If buffer is already full, go slow.
757 __ ld(_tmp1, index);
758 __ beqz(_tmp1, L_slowpath);
759 __ subi(_tmp1, _tmp1, wordSize);
760 __ sd(_tmp1, index);
761 __ ld(_tmp2, buffer);
762
763 // Store the object in queue.
764 // If object is narrow, we need to decode it before inserting.
765 __ add(_tmp1, _tmp1, _tmp2);
766 if (_narrow) {
767 __ decode_heap_oop_not_null(_tmp2, _obj);
768 __ sd(_tmp2, Address(_tmp1));
769 } else {
770 __ sd(_obj, Address(_tmp1));
771 }
772
773 // Fast-path exits here.
774 if (L_done != nullptr) {
775 __ j(*L_done);
776 } else {
777 __ j(L_through);
778 }
779
780 // Slow-path: call runtime to handle.
781 __ bind(L_slowpath);
782
783 {
784 SaveLiveRegisters slr(&masm, this);
785
786 // Go to runtime and handle the rest there.
787 __ mv(c_rarg0, _obj);
788 __ la(ra, RuntimeAddress(keepalive_runtime_entry_addr()));
789 __ jalr(ra);
790 }
791 if (L_done != nullptr) {
792 __ j(*L_done);
793 } else {
794 __ bind(L_through);
795 }
796 }
797
798 void ShenandoahBarrierStubC2::lrb(MacroAssembler& masm) {
799 Label L_slow;
800
801 // If another barrier is enabled as well, do a runtime check for a specific barrier.
802 if (_needs_keep_alive_barrier) {
803 char state_to_check = ShenandoahHeap::HAS_FORWARDED | (_needs_load_ref_weak_barrier ? ShenandoahHeap::WEAK_ROOTS : 0);
804 Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(state_to_check)));
805 __ lbu(_tmp1, gc_state_fast);
806 maybe_far_jump_if_zero(masm, _tmp1);
807 }
808
809 // If weak references are being processed, weak/phantom loads need to go slow,
810 // regardless of their cset status.
811 if (_needs_load_ref_weak_barrier) {
812 Address gc_state_fast(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::WEAK_ROOTS)));
813 __ lbu(_tmp1, gc_state_fast);
814 __ bnez(_tmp1, L_slow);
815 }
816
817 // Cset-check. Fall-through to slow if in collection set.
818 if (_narrow) {
819 __ decode_heap_oop_not_null(_tmp2, _obj);
820 } else {
821 __ mv(_tmp2, _obj);
822 }
823
824 if (AOTCodeCache::is_on_for_dump()) {
825 __ lwu(_tmp1, ExternalAddress(AOTRuntimeConstants::grain_shift_address()));
826 __ srl(_tmp2, _tmp2, _tmp1);
827 __ ld(_tmp1, ExternalAddress(AOTRuntimeConstants::cset_base_address()));
828 } else {
829 __ mv(_tmp1, ShenandoahHeap::in_cset_fast_test_addr());
830 __ srli(_tmp2, _tmp2, ShenandoahHeapRegion::region_size_bytes_shift_jint());
831 }
832 __ add(_tmp1, _tmp1, _tmp2);
833 __ lbu(_tmp1, Address(_tmp1, 0));
834 maybe_far_jump_if_zero(masm, _tmp1);
835
836 // Slow path
837 __ bind(L_slow);
838
839 // Obj is the result, need to temporarily stop preserving it.
840 bool is_obj_preserved = is_preserved(_obj);
841 if (is_obj_preserved) {
842 dont_preserve(_obj);
843 }
844 {
845 SaveLiveRegisters slr(&masm, this);
846
847 // Shuffle in the arguments. The end result should be:
848 // c_rarg0 <- obj
849 // c_rarg1 <- lea(addr)
850 if (c_rarg0 == _obj) {
851 __ la(c_rarg1, _addr);
852 } else if (c_rarg1 == _obj) {
853 __ mv(_tmp1, c_rarg1);
854 __ la(c_rarg1, _addr);
855 __ mv(c_rarg0, _tmp1);
856 } else {
857 assert_different_registers(c_rarg1, _obj);
858 __ la(c_rarg1, _addr);
859 __ mv(c_rarg0, _obj);
860 }
861
862 // Go to runtime and handle the rest there.
863 __ la(ra, RuntimeAddress(lrb_runtime_entry_addr()));
864 __ jalr(ra);
865
866 // Save the result where needed. Narrow entries return narrowOop (32 bits)
867 // we need to zero the upper 32 bits of x10.
868 if (_narrow) {
869 __ zext(_obj, x10, 32);
870 } else {
871 __ mv(_obj, x10);
872 }
873 }
874 if (is_obj_preserved) {
875 preserve(_obj);
876 }
877
878 __ j(*continuation());
879 }
880
881 int ShenandoahBarrierStubC2::available_gp_registers() {
882 Unimplemented(); // Not used
883 return 0;
884 }
885
886 bool ShenandoahBarrierStubC2::is_special_register(Register r) {
887 Unimplemented(); // Not used
888 return true;
889 }
890
891 void ShenandoahBarrierStubC2::post_init() {
892 // Do nothing.
893 }
894
895 #endif // COMPILER2