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/shenandoahNMethod.inline.hpp"
34 #include "gc/shenandoah/shenandoahRuntime.hpp"
35 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
36 #include "interpreter/interp_masm.hpp"
37 #include "interpreter/interpreter.hpp"
38 #include "nativeInst_riscv.hpp"
39 #include "runtime/javaThread.hpp"
40 #include "runtime/sharedRuntime.hpp"
41 #ifdef COMPILER1
42 #include "c1/c1_LIRAssembler.hpp"
43 #include "c1/c1_MacroAssembler.hpp"
44 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
45 #endif
46 #ifdef COMPILER2
47 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
48 #include "opto/output.hpp"
49 #endif
50
51 #define __ masm->
52
53 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
54 Register src, Register dst, Register count, RegSet saved_regs) {
55 if (is_oop) {
56 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
57 if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) {
58
59 Label done;
60
61 // Avoid calling runtime if count == 0
62 __ beqz(count, done);
63
64 // Is GC active?
65 Address gc_state(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
66 assert_different_registers(src, dst, count, t0);
67
68 assert(!saved_regs.contains(t0), "Sanity: about to clobber t0");
69
70 __ lbu(t0, gc_state);
71 if (ShenandoahSATBBarrier && dest_uninitialized) {
72 __ test_bit(t0, t0, ShenandoahHeap::HAS_FORWARDED_BITPOS);
73 __ beqz(t0, done);
74 } else {
75 __ andi(t0, t0, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING);
76 __ beqz(t0, done);
77 }
78
79 __ push_call_clobbered_registers();
80 // If arguments are not in proper places, shuffle them.
81 // Doing this via the stack is the most straight-forward way to avoid
82 // accidentally smashing any register.
83 if (c_rarg0 != src || c_rarg1 != dst || c_rarg2 != count) {
84 __ push_reg(RegSet::of(src), sp);
85 __ push_reg(RegSet::of(dst), sp);
86 __ push_reg(RegSet::of(count), sp);
87 __ pop_reg(RegSet::of(c_rarg2), sp);
88 __ pop_reg(RegSet::of(c_rarg1), sp);
89 __ pop_reg(RegSet::of(c_rarg0), sp);
90 }
91 address target = nullptr;
92 if (UseCompressedOops) {
93 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_narrow_oop);
94 } else {
95 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_oop);
96 }
97 __ call_VM_leaf(target, 3);
98 __ pop_call_clobbered_registers();
99 __ bind(done);
100 }
101 }
102 }
103
104 void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
105 Register start, Register count, Register tmp) {
106 if (ShenandoahCardBarrier && is_oop) {
107 gen_write_ref_array_post_barrier(masm, decorators, start, count, tmp);
108 }
109 }
110
111 void ShenandoahBarrierSetAssembler::satb_barrier(MacroAssembler* masm,
112 Register obj,
113 Register pre_val,
114 Register thread,
115 Register tmp1,
116 Register tmp2) {
117 assert(ShenandoahSATBBarrier, "Should be checked by caller");
118 assert(thread == xthread, "must be");
119
120 Label done;
121 Label runtime;
122
123 assert_different_registers(obj, pre_val, tmp1, tmp2);
124 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
125
126 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
127 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
128
129 // Is marking active?
130 Address gc_state(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
131 __ lbu(t1, gc_state);
132 __ test_bit(t1, t1, ShenandoahHeap::MARKING_BITPOS);
133 __ beqz(t1, done);
134
135 // Do we need to load the previous value?
136 if (obj != noreg) {
137 if (UseCompressedOops) {
138 __ lwu(pre_val, Address(obj, 0));
139 __ decode_heap_oop(pre_val);
140 } else {
141 __ ld(pre_val, Address(obj, 0));
142 }
143 }
144
145 // Is the previous value null?
146 __ beqz(pre_val, done);
147
148 // Can we store original value in the thread's buffer?
149 // Is index == 0?
150 // (The index field is typed as size_t.)
151 __ ld(tmp1, index); // tmp := *index_adr
152 __ beqz(tmp1, runtime); // tmp == 0? If yes, goto runtime
153
154 __ subi(tmp1, tmp1, wordSize); // tmp := tmp - wordSize
155 __ sd(tmp1, index); // *index_adr := tmp
156 __ ld(tmp2, buffer);
157 __ add(tmp1, tmp1, tmp2); // tmp := tmp + *buffer_adr
158
159 // Record the previous value
160 __ sd(pre_val, Address(tmp1, 0));
161 __ j(done);
162
163 // Slow-path call.
164 __ bind(runtime);
165 __ enter();
166 __ push_call_clobbered_registers();
167 if (c_rarg0 != pre_val) {
168 __ mv(c_rarg0, pre_val);
169 }
170 // Calling with super_call_VM_leaf with c_rarg0 bypasses interpreter checks and avoids any moves.
171 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), c_rarg0);
172 __ pop_call_clobbered_registers();
173 __ leave();
174
175 __ bind(done);
176 }
177
178 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm,
179 Register dst,
180 Address load_addr,
181 DecoratorSet decorators) {
182 assert(ShenandoahLoadRefBarrier, "Should be enabled");
183 assert(dst != t1 && load_addr.base() != t1, "need t1");
184 assert_different_registers(load_addr.base(), t0, t1);
185
186 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
187 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
188 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
189 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
190 bool is_narrow = UseCompressedOops && !is_native;
191
192 Label heap_stable, not_cset;
193 Address gc_state(xthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
194 __ lbu(t1, gc_state);
195
196 // Check for heap stability
197 if (is_strong) {
198 __ test_bit(t1, t1, ShenandoahHeap::HAS_FORWARDED_BITPOS);
199 __ beqz(t1, heap_stable);
200 } else {
201 Label lrb;
202 __ test_bit(t0, t1, ShenandoahHeap::WEAK_ROOTS_BITPOS);
203 __ bnez(t0, lrb);
204 __ test_bit(t0, t1, ShenandoahHeap::HAS_FORWARDED_BITPOS);
205 __ beqz(t0, heap_stable);
206 __ bind(lrb);
207 }
208
209 // use x11 for load address
210 Register result_dst = dst;
211 if (dst == x11) {
212 __ mv(t1, dst);
213 dst = t1;
214 }
215
216 // Save x10 and x11, unless it is an output register
217 RegSet saved_regs = RegSet::of(x10, x11) - result_dst;
218 __ push_reg(saved_regs, sp);
219 __ la(x11, load_addr);
220 __ mv(x10, dst);
221
222 // Test for in-cset
223 if (is_strong) {
224 __ mv(t1, ShenandoahHeap::in_cset_fast_test_addr());
225 __ srli(t0, x10, ShenandoahHeapRegion::region_size_bytes_shift_jint());
226 __ add(t1, t1, t0);
227 __ lbu(t1, Address(t1));
228 __ test_bit(t0, t1, 0);
229 __ beqz(t0, not_cset);
230 }
231
232 // Slow-path call
233 __ enter();
234 __ push_call_clobbered_registers();
235 address target = nullptr;
236 if (is_strong) {
237 if (is_narrow) {
238 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow);
239 } else {
240 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong);
241 }
242 } else if (is_weak) {
243 if (is_narrow) {
244 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow);
245 } else {
246 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak);
247 }
248 } else {
249 assert(is_phantom, "only remaining strength");
250 assert(!is_narrow, "phantom access cannot be narrow");
251 target = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom);
252 }
253 // Calling with super_call_VM_leaf with c_rarg0/1 bypasses interpreter checks and avoids any moves.
254 __ super_call_VM_leaf(target, c_rarg0, c_rarg1);
255 __ mv(t0, x10);
256 __ pop_call_clobbered_registers();
257 __ mv(x10, t0);
258 __ leave();
259
260 __ bind(not_cset);
261 __ mv(result_dst, x10);
262 __ pop_reg(saved_regs, sp);
263
264 __ bind(heap_stable);
265 }
266
267 //
268 // Arguments:
269 //
270 // Inputs:
271 // src: oop location to load from, might be clobbered
272 //
273 // Output:
274 // dst: oop loaded from src location
275 //
276 // Kill:
277 // x30 (tmp reg)
278 //
279 // Alias:
280 // dst: x30 (might use x30 as temporary output register to avoid clobbering src)
281 //
282 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm,
283 DecoratorSet decorators,
284 BasicType type,
285 Register dst,
286 Address src,
287 Register tmp1,
288 Register tmp2) {
289 // 1: non-reference load, no additional barrier is needed
290 if (!is_reference_type(type)) {
291 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
292 return;
293 }
294
295 // 2: load a reference from src location and apply LRB if needed
296 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
297 Register result_dst = dst;
298
299 // Preserve src location for LRB
300 RegSet saved_regs;
301 if (dst == src.base()) {
302 dst = (src.base() == x28) ? x29 : x28;
303 saved_regs = RegSet::of(dst);
304 __ push_reg(saved_regs, sp);
305 }
306 assert_different_registers(dst, src.base());
307
308 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
309
310 load_reference_barrier(masm, dst, src, decorators);
311
312 if (dst != result_dst) {
313 __ mv(result_dst, dst);
314 dst = result_dst;
315 }
316
317 if (saved_regs.bits() != 0) {
318 __ pop_reg(saved_regs, sp);
319 }
320 } else {
321 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
322 }
323
324 // 3: apply keep-alive barrier if needed
325 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
326 satb_barrier(masm /* masm */,
327 noreg /* obj */,
328 dst /* pre_val */,
329 xthread /* thread */,
330 tmp1 /* tmp1 */,
331 tmp2 /* tmp2 */);
332 }
333 }
334
335 void ShenandoahBarrierSetAssembler::card_barrier(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2) {
336 assert(ShenandoahCardBarrier, "Should have been checked by caller");
337 assert(CardTable::dirty_card_val() == 0, "must be");
338 assert_different_registers(obj, tmp1, tmp2);
339
340 __ srli(obj, obj, CardTable::card_shift());
341
342 Address curr_ct_holder_addr(xthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
343 __ ld(tmp1, curr_ct_holder_addr);
344 __ add(tmp1, obj, tmp1);
345
346 if (UseCondCardMark) {
347 Label L_already_dirty;
348 __ lbu(tmp2, Address(tmp1));
349 __ beqz(tmp2, L_already_dirty);
350 __ sb(zr, Address(tmp1));
351 __ bind(L_already_dirty);
352 } else {
353 __ sb(zr, Address(tmp1));
354 }
355 }
356
357 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
358 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
359 // 1: non-reference types require no barriers
360 if (!is_reference_type(type)) {
361 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2, tmp3);
362 return;
363 }
364
365 // Flatten object address right away for simplicity: likely needed by barriers
366 if (dst.offset() == 0) {
367 if (dst.base() != tmp3) {
368 __ mv(tmp3, dst.base());
369 }
370 } else {
371 __ la(tmp3, dst);
372 }
373
374 // 2: pre-barrier: SATB needs the previous value
375 if (ShenandoahBarrierSet::need_satb_barrier(decorators, type)) {
376 satb_barrier(masm,
377 tmp3 /* obj */,
378 tmp2 /* pre_val */,
379 xthread /* thread */,
380 tmp1 /* tmp */,
381 t0 /* tmp2 */);
382 }
383
384 // Store!
385 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), val, noreg, noreg, noreg);
386
387 // 3: post-barrier: card barrier needs store address
388 bool storing_non_null = (val != noreg);
389 if (ShenandoahBarrierSet::need_card_barrier(decorators, type) && storing_non_null) {
390 card_barrier(masm, tmp3, tmp1, tmp2);
391 }
392 }
393
394 void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
395 Register obj, Register tmp, Label& slowpath) {
396 Label done;
397 // Resolve jobject
398 BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath);
399
400 // Check for null.
401 __ beqz(obj, done);
402
403 assert(obj != t1, "need t1");
404 Address gc_state(jni_env, ShenandoahThreadLocalData::gc_state_offset() - JavaThread::jni_environment_offset());
405 __ lbu(t1, gc_state);
406
407 // Check for heap in evacuation phase
408 __ test_bit(t0, t1, ShenandoahHeap::EVACUATION_BITPOS);
409 __ bnez(t0, slowpath);
410
411 __ bind(done);
412 }
413
414 void ShenandoahBarrierSetAssembler::try_peek_weak_handle_in_nmethod(MacroAssembler *masm, Register weak_handle,
415 Register obj, Register tmp, Label& slow_path) {
416 assert_different_registers(weak_handle, tmp, noreg);
417 assert_different_registers(obj, tmp, noreg);
418
419
420 Label done;
421
422 // Peek weak handle using the standard implementation.
423 BarrierSetAssembler::try_peek_weak_handle_in_nmethod(masm, weak_handle, obj, tmp, slow_path);
424
425 // Check if the reference is null, and if it is, take the fast path.
426 __ beqz(obj, done);
427
428 Address gc_state(xthread, ShenandoahThreadLocalData::gc_state_offset());
429 __ lbu(tmp, gc_state);
430
431 // Check if the heap is under weak-reference/roots processing, in
432 // which case we need to take the slow path.
433 __ test_bit(tmp, tmp, ShenandoahHeap::WEAK_ROOTS_BITPOS);
434 __ bnez(tmp, slow_path);
435 __ bind(done);
436 }
437
438 void ShenandoahBarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& L_error) {
439 // Check if the oop is in the right area of memory
440 __ mv(tmp2, (intptr_t) Universe::verify_oop_mask());
441 __ andr(tmp1, obj, tmp2);
442 __ mv(tmp2, (intptr_t) Universe::verify_oop_bits());
443
444 // Compare tmp1 and tmp2.
445 __ bne(tmp1, tmp2, L_error);
446
447 // This routine is sometimes called before applying GC barriers.
448 // With +COH, loading the klass may end up loading forwarding pointer instead.
449 Label L_skip;
450 if (UseCompactObjectHeaders) {
451 Address gc_state(xthread, ShenandoahThreadLocalData::gc_state_offset());
452 __ lbu(tmp1, gc_state);
453 __ test_bit(tmp1, tmp1, ShenandoahHeap::HAS_FORWARDED_BITPOS);
454 __ bnez(tmp1, L_skip);
455 }
456
457 // Make sure klass is 'reasonable', which is not zero.
458 __ load_narrow_klass(tmp1, obj);
459 __ beqz(tmp1, L_error);
460
461 __ bind(L_skip);
462 }
463
464 void ShenandoahBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
465 Register start, Register count, Register tmp) {
466 assert(ShenandoahCardBarrier, "Did you mean to enable ShenandoahCardBarrier?");
467
468 Label L_loop, L_done;
469 const Register end = count;
470
471 // Zero count? Nothing to do.
472 __ beqz(count, L_done);
473
474 // end = start + count << LogBytesPerHeapOop
475 // last element address to make inclusive
476 __ shadd(end, count, start, tmp, LogBytesPerHeapOop);
477 __ subi(end, end, BytesPerHeapOop);
478 __ srli(start, start, CardTable::card_shift());
479 __ srli(end, end, CardTable::card_shift());
480
481 // number of bytes to copy
482 __ sub(count, end, start);
483
484 Address curr_ct_holder_addr(xthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
485 __ ld(tmp, curr_ct_holder_addr);
486 __ add(start, start, tmp);
487
488 __ bind(L_loop);
489 __ add(tmp, start, count);
490 __ sb(zr, Address(tmp));
491 __ subi(count, count, 1);
492 __ bgez(count, L_loop);
493 __ bind(L_done);
494 }
495
496 #undef __
497
498 address ShenandoahBarrierSetAssembler::parse_jump_address(address pc) {
499 NativeInstruction* ni = nativeInstruction_at(pc);
500 assert(ni->is_jump(), "Must be a jump");
501 NativeJump* jmp = nativeJump_at(pc);
502 return jmp->jump_destination();
503 }
504
505 static uint32_t encode_patchable_nop() {
506 return 0x00000013;
507 }
508
509 static uint32_t encode_patchable_jump(address pc, address target_pc) {
510 int32_t disp = checked_cast<int32_t>((intptr_t)target_pc - (intptr_t)pc);
511 return Assembler::encode_jal(x0, disp);
512 }
513
514 void ShenandoahBarrierSetAssembler::insert_patchable_nop(address pc) {
515 *((uint32_t*)pc) = encode_patchable_nop();
516 assert(nativeInstruction_at(pc)->is_nop(), "Sanity");
517 }
518
519 void ShenandoahBarrierSetAssembler::insert_patchable_jump(address pc, address target_pc) {
520 *((uint32_t*)pc) = encode_patchable_jump(pc, target_pc);
521 }
522
523 bool ShenandoahBarrierSetAssembler::is_patchable_nop(address pc) {
524 return *((uint32_t*)pc) == encode_patchable_nop();
525 }
526
527 bool ShenandoahBarrierSetAssembler::is_patchable_jump(address pc, address target_pc) {
528 return *((uint32_t*)pc) == encode_patchable_jump(pc, target_pc);
529 }
530
531 #ifdef COMPILER1
532
533 #define __ ce->masm()->
534
535 void ShenandoahBarrierSetAssembler::keepalive_barrier_c1_stub(LIR_Assembler* ce, ShenandoahKeepaliveBarrierStub* stub) {
536 __ bind(*stub->entry());
537
538 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
539
540 Register obj = stub->obj()->as_register();
541
542 if (stub->do_load()) {
543 ce->mem2reg(stub->addr(), stub->obj(), T_OBJECT, lir_patch_none, nullptr, false /* wide */);
544 }
545 __ beqz(obj, *stub->continuation(), /* is_far */ true);
546
547 ce->store_parameter(obj, 0);
548 __ far_call(RuntimeAddress(bs->keepalive_barrier_stub()));
549 __ j(*stub->continuation());
550 }
551
552 void ShenandoahBarrierSetAssembler::load_reference_barrier_c1_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
553 __ bind(*stub->entry());
554
555 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*) BarrierSet::barrier_set()->barrier_set_c1();
556
557 Register obj = stub->obj()->as_register();
558 Register addr = stub->addr()->as_pointer_register();
559 Register slow_result = stub->slow_result()->as_register();
560 assert_different_registers(obj, addr, slow_result);
561 assert(slow_result == x10, "C1 must know about our slow call result register");
562
563 ce->store_parameter(obj, 0);
564 ce->store_parameter(addr, 1);
565 __ far_call(RuntimeAddress(bs->load_reference_barrier_stub(stub->decorators())));
566 if (obj != slow_result) {
567 __ mv(obj, slow_result);
568 }
569
570 __ j(*stub->continuation());
571 }
572
573 #undef __
574
575 #define __ sasm->
576
577 void ShenandoahBarrierSetAssembler::keepalive_barrier_c1_runtime_stub(StubAssembler* sasm) {
578 __ prologue("shenandoah_keepalive_barrier", false);
579 const Register tmp_obj = x10;
580 const Register tmp1 = x11;
581 const Register tmp2 = x12;
582 __ push_reg(RegSet::of(tmp1, tmp2, tmp_obj), sp);
583 __ load_parameter(0, tmp_obj);
584 satb_barrier(sasm, noreg, tmp_obj, xthread, tmp1, tmp2);
585 __ pop_reg(RegSet::of(tmp1, tmp2, tmp_obj), sp);
586 __ epilogue();
587 }
588
589 void ShenandoahBarrierSetAssembler::load_reference_barrier_c1_runtime_stub(StubAssembler* sasm, DecoratorSet decorators) {
590 __ prologue("shenandoah_load_reference_barrier", false);
591 const Register tmp_obj = x10;
592 const Register tmp_addr = x11;
593 __ push_reg(RegSet::of(tmp_addr), sp);
594 __ load_parameter(0, tmp_obj);
595 __ load_parameter(1, tmp_addr);
596 load_reference_barrier(sasm, tmp_obj, Address(tmp_addr, 0), decorators);
597 __ pop_reg(RegSet::of(tmp_addr), sp);
598 __ epilogue();
599 }
600
601 #undef __
602
603 #endif // COMPILER1
604
605 #ifdef COMPILER2
606
607 #undef __
608 #define __ masm->
609
610 void ShenandoahBarrierSetAssembler::load_c2(const MachNode* node, MacroAssembler* masm, Register dst, Address src, Register tmp1, Register tmp2, bool is_narrow) {
611 // Do the actual load. This load is the candidate for implicit null check, and MUST come first.
612 if (is_narrow) {
613 __ lwu(dst, src);
614 } else {
615 __ ld(dst, src);
616 }
617
618 ShenandoahBarrierStubC2::load_post(masm, node, dst, src, tmp1, tmp2, is_narrow);
619 }
620
621 void ShenandoahBarrierSetAssembler::store_c2(const MachNode* node, MacroAssembler* masm, Address dst, bool dst_narrow,
622 Register src, bool src_narrow, Register tmp1, Register tmp2, Register tmp3) {
623
624 ShenandoahBarrierStubC2::store_pre(masm, node, dst, tmp1, tmp2, tmp3, dst_narrow);
625
626 // Do the actual store
627 if (dst_narrow) {
628 if (!src_narrow) {
629 // Need to encode into tmp, because we cannot clobber src.
630 assert(tmp1 != noreg, "need temp register");
631 if ((node->barrier_data() & ShenandoahBitNotNull) == 0) {
632 __ encode_heap_oop(tmp1, src);
633 } else {
634 __ encode_heap_oop_not_null(tmp1, src);
635 }
636 src = tmp1;
637 }
638 __ sw(src, dst);
639 } else {
640 __ sd(src, dst);
641 }
642
643 ShenandoahBarrierStubC2::store_post(masm, node, dst, tmp2, tmp3);
644 }
645
646 void ShenandoahBarrierSetAssembler::compare_and_set_c2(const MachNode* node, MacroAssembler* masm, Register res, Register addr,
647 Register oldval, Register newval, Register tmp1, Register tmp2, Register tmp3, bool exchange, bool narrow, bool is_acquire) {
648 const Assembler::Aqrl acquire = is_acquire ? Assembler::aq : Assembler::relaxed;
649 const Assembler::Aqrl release = Assembler::rl;
650 const Assembler::operand_size size = narrow ? Assembler::uint32 : Assembler::int64;
651
652 ShenandoahBarrierStubC2::load_store_pre(masm, node, Address(addr), tmp1, tmp2, tmp3, narrow);
653
654 // CAS!
655 __ cmpxchg(addr, oldval, newval, size, acquire, release, /* result */ res, !exchange /* result_as_bool */);
656
657 ShenandoahBarrierStubC2::load_store_post(masm, node, Address(addr, 0), tmp2, tmp3);
658 }
659
660 void ShenandoahBarrierSetAssembler::get_and_set_c2(const MachNode* node, MacroAssembler* masm, Register preval,
661 Register newval, Register addr, Register tmp1, Register tmp2, Register tmp3, bool is_acquire) {
662 const bool is_narrow = node->bottom_type()->isa_narrowoop();
663
664 ShenandoahBarrierStubC2::load_store_pre(masm, node, Address(addr, 0), tmp1, tmp2, tmp3, is_narrow);
665
666 if (is_narrow) {
667 if (is_acquire) {
668 __ atomic_xchgalwu(preval, newval, addr);
669 } else {
670 __ atomic_xchgwu(preval, newval, addr);
671 }
672 } else {
673 if (is_acquire) {
674 __ atomic_xchgal(preval, newval, addr);
675 } else {
676 __ atomic_xchg(preval, newval, addr);
677 }
678 }
679
680 ShenandoahBarrierStubC2::load_store_post(masm, node, Address(addr, 0), tmp2, tmp3);
681 }
682
683 #undef __
684 #define __ masm.
685
686 void ShenandoahBarrierStubC2::cardtable(MacroAssembler& masm, Address address, Register tmp1, Register tmp2) {
687 assert(CardTable::dirty_card_val() == 0, "must be");
688 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
689
690 // tmp1 = card table base (holder)
691 Address curr_ct_holder_addr(xthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
692 __ ld(tmp1, curr_ct_holder_addr);
693
694 // tmp1 = effective address
695 __ la(tmp2, address);
696
697 // tmp2 = &card_table[ addr >> CardTable::card_shift() ] ; card index
698 __ srli(tmp2, tmp2, CardTable::card_shift());
699 __ add(tmp2, tmp2, tmp1);
700
701 if (UseCondCardMark) {
702 Label L_already_dirty;
703 __ lbu(tmp1, Address(tmp2));
704 __ beqz(tmp1, L_already_dirty);
705 __ sb(zr, Address(tmp2));
706 __ bind(L_already_dirty);
707 } else {
708 __ sb(zr, Address(tmp2));
709 }
710 }
711
712 void ShenandoahBarrierStubC2::patchable_jump(MacroAssembler& masm, const char gc_state, bool jump_when_state, Label* L_target) {
713 PhaseOutput* const output = Compile::current()->output();
714 if (output->in_scratch_emit_size()) {
715 // Avoid binding L_target in scratch emits.
716 // We know the patched check is exactly one incompressible instruction long.
717 Assembler::IncompressibleScope scope(&masm);
718 __ nop();
719 return;
720 }
721
722 // Emit the unconditional branch in the first version of the method.
723 // Let the rest of runtime figure out how to manage it.
724 __ relocate(patchable_barrier_Relocation::spec(ShenandoahNMethod::encode_to_reloc(gc_state, jump_when_state)));
725 __ j(*L_target);
726 }
727
728 void ShenandoahBarrierStubC2::enter_if_gc_state(MacroAssembler& masm, const char test_state) {
729 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
730 patchable_jump_if_gc_state(masm, test_state, entry());
731 __ bind(*continuation());
732 }
733
734 void ShenandoahBarrierStubC2::emit_code(MacroAssembler& masm) {
735 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
736 assert(_needs_keep_alive_barrier || _needs_load_ref_barrier, "Why are you here?");
737
738 __ bind(*entry());
739
740 // If we need to load ourselves, do it here.
741 if (_do_load) {
742 if (_narrow) {
743 __ lwu(_obj, _addr);
744 } else {
745 __ ld(_obj, _addr);
746 }
747 }
748
749 // If the object is null, there is no point in applying barriers.
750 maybe_far_jump_if_zero(masm, _obj);
751
752 // We need to make sure that loads done by callers survive across slow-path calls.
753 // For self-loads, we need to care about the case when both KA and LRB are enabled (rare).
754 bool needs_both_barriers = _needs_keep_alive_barrier && _needs_load_ref_barrier;
755 if (!_do_load || needs_both_barriers) {
756 preserve(_obj);
757 }
758
759 // Go for barriers. Barriers can return straight to continuation, as long
760 // as another barrier is not needed and we can reach the fastpath.
761 if (needs_both_barriers) {
762 keepalive(masm, nullptr);
763 lrb(masm);
764 } else if (_needs_keep_alive_barrier) {
765 keepalive(masm, continuation());
766 } else if (_needs_load_ref_barrier) {
767 lrb(masm);
768 } else {
769 ShouldNotReachHere();
770 }
771 }
772
773 void ShenandoahBarrierStubC2::maybe_far_jump_if_zero(MacroAssembler& masm, Register reg) {
774 Label L_short_jump;
775 __ bnez(reg, L_short_jump);
776 __ j(*continuation());
777 __ bind(L_short_jump);
778 }
779
780 void ShenandoahBarrierStubC2::keepalive(MacroAssembler& masm, Label* L_done) {
781 Address index(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
782 Address buffer(xthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
783 Label L_through, L_slowpath;
784
785 // If another barrier is enabled as well, do a check for a specific barrier.
786 if (_needs_load_ref_barrier) {
787 assert(L_done == nullptr, "Should be");
788 char state_to_check = ShenandoahHeap::MARKING;
789 patchable_jump_if_not_gc_state(masm, state_to_check, &L_through);
790 }
791
792 // Fast-path: put object into buffer.
793 // If buffer is already full, go slow.
794 __ ld(_tmp1, index);
795 __ beqz(_tmp1, L_slowpath);
796 __ subi(_tmp1, _tmp1, wordSize);
797 __ sd(_tmp1, index);
798 __ ld(_tmp2, buffer);
799
800 // Store the object in queue.
801 // If object is narrow, we need to decode it before inserting.
802 __ add(_tmp1, _tmp1, _tmp2);
803 if (_narrow) {
804 __ decode_heap_oop_not_null(_tmp2, _obj);
805 __ sd(_tmp2, Address(_tmp1));
806 } else {
807 __ sd(_obj, Address(_tmp1));
808 }
809
810 // Fast-path exits here.
811 if (L_done != nullptr) {
812 __ j(*L_done);
813 } else {
814 __ j(L_through);
815 }
816
817 // Slow-path: call runtime to handle.
818 __ bind(L_slowpath);
819
820 {
821 SaveLiveRegisters slr(&masm, this);
822
823 // Go to runtime and handle the rest there.
824 __ mv(c_rarg0, _obj);
825 __ la(ra, RuntimeAddress(keepalive_runtime_entry_addr()));
826 __ jalr(ra);
827 }
828 if (L_done != nullptr) {
829 __ j(*L_done);
830 } else {
831 __ bind(L_through);
832 }
833 }
834
835 void ShenandoahBarrierStubC2::lrb(MacroAssembler& masm) {
836 Label L_slow;
837
838 // If another barrier is enabled as well, do a check for a specific barrier.
839 if (_needs_keep_alive_barrier) {
840 char state_to_check = ShenandoahHeap::HAS_FORWARDED | (_needs_load_ref_weak_barrier ? ShenandoahHeap::WEAK_ROOTS : 0);
841 patchable_jump_if_not_gc_state(masm, state_to_check, continuation());
842 }
843
844 // If weak references are being processed, weak/phantom loads need to go slow,
845 // regardless of their cset status.
846 if (_needs_load_ref_weak_barrier) {
847 char state_to_check = ShenandoahHeap::WEAK_ROOTS;
848 patchable_jump_if_gc_state(masm, state_to_check, &L_slow);
849 }
850
851 // Cset-check. Fall-through to slow if in collection set.
852 if (_narrow) {
853 __ decode_heap_oop_not_null(_tmp2, _obj);
854 } else {
855 __ mv(_tmp2, _obj);
856 }
857
858 __ mv(_tmp1, ShenandoahHeap::in_cset_fast_test_addr());
859 __ srli(_tmp2, _tmp2, ShenandoahHeapRegion::region_size_bytes_shift_jint());
860 __ add(_tmp1, _tmp1, _tmp2);
861 __ lbu(_tmp1, Address(_tmp1, 0));
862 maybe_far_jump_if_zero(masm, _tmp1);
863
864 // Slow path
865 __ bind(L_slow);
866
867 // Obj is the result, need to temporarily stop preserving it.
868 bool is_obj_preserved = is_preserved(_obj);
869 if (is_obj_preserved) {
870 dont_preserve(_obj);
871 }
872 {
873 SaveLiveRegisters slr(&masm, this);
874
875 // Shuffle in the arguments. The end result should be:
876 // c_rarg0 <- obj
877 // c_rarg1 <- lea(addr)
878 if (c_rarg0 == _obj) {
879 __ la(c_rarg1, _addr);
880 } else if (c_rarg1 == _obj) {
881 __ mv(_tmp1, c_rarg1);
882 __ la(c_rarg1, _addr);
883 __ mv(c_rarg0, _tmp1);
884 } else {
885 assert_different_registers(c_rarg1, _obj);
886 __ la(c_rarg1, _addr);
887 __ mv(c_rarg0, _obj);
888 }
889
890 // Go to runtime and handle the rest there.
891 __ la(ra, RuntimeAddress(lrb_runtime_entry_addr()));
892 __ jalr(ra);
893
894 // Save the result where needed. Narrow entries return narrowOop (32 bits)
895 // we need to zero the upper 32 bits of x10.
896 if (_narrow) {
897 __ zext_w(_obj, x10);
898 } else {
899 __ mv(_obj, x10);
900 }
901 }
902 if (is_obj_preserved) {
903 preserve(_obj);
904 }
905
906 __ j(*continuation());
907 }
908
909 int ShenandoahBarrierStubC2::available_gp_registers() {
910 Unimplemented(); // Not used
911 return 0;
912 }
913
914 bool ShenandoahBarrierStubC2::is_special_register(Register r) {
915 Unimplemented(); // Not used
916 return true;
917 }
918
919 void ShenandoahBarrierStubC2::post_init() {
920 // Do nothing.
921 }
922
923 #endif // COMPILER2