1 /*
2 * Copyright (c) 2026, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2018, 2021, Red Hat, Inc. All rights reserved.
4 * Copyright Amazon.com Inc. or its affiliates. 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/shenandoahForwarding.hpp"
32 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
33 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
34 #include "gc/shenandoah/shenandoahRuntime.hpp"
35 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "runtime/javaThread.hpp"
38 #include "runtime/sharedRuntime.hpp"
39 #include "utilities/macros.hpp"
40 #ifdef COMPILER1
41 #include "c1/c1_LIRAssembler.hpp"
42 #include "c1/c1_MacroAssembler.hpp"
43 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
44 #endif
45 #ifdef COMPILER2
46 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
47 #endif
48
49 #define __ masm->
50
51 static void save_machine_state(MacroAssembler* masm, bool handle_gpr, bool handle_fp) {
52 if (handle_gpr) {
53 __ push_IU_state();
54 }
55
56 if (handle_fp) {
57 // Some paths can be reached from the c2i adapter with live fp arguments in registers.
58 assert(Argument::n_float_register_parameters_j == 8, "8 fp registers to save at java call");
59
60 const int xmm_size = wordSize * 2;
61 __ subptr(rsp, xmm_size * 8);
62 __ movdbl(Address(rsp, xmm_size * 0), xmm0);
63 __ movdbl(Address(rsp, xmm_size * 1), xmm1);
64 __ movdbl(Address(rsp, xmm_size * 2), xmm2);
65 __ movdbl(Address(rsp, xmm_size * 3), xmm3);
66 __ movdbl(Address(rsp, xmm_size * 4), xmm4);
67 __ movdbl(Address(rsp, xmm_size * 5), xmm5);
68 __ movdbl(Address(rsp, xmm_size * 6), xmm6);
69 __ movdbl(Address(rsp, xmm_size * 7), xmm7);
70 }
71 }
72
73 static void restore_machine_state(MacroAssembler* masm, bool handle_gpr, bool handle_fp) {
74 if (handle_fp) {
75 const int xmm_size = wordSize * 2;
76 __ movdbl(xmm0, Address(rsp, xmm_size * 0));
77 __ movdbl(xmm1, Address(rsp, xmm_size * 1));
78 __ movdbl(xmm2, Address(rsp, xmm_size * 2));
79 __ movdbl(xmm3, Address(rsp, xmm_size * 3));
80 __ movdbl(xmm4, Address(rsp, xmm_size * 4));
81 __ movdbl(xmm5, Address(rsp, xmm_size * 5));
82 __ movdbl(xmm6, Address(rsp, xmm_size * 6));
83 __ movdbl(xmm7, Address(rsp, xmm_size * 7));
84 __ addptr(rsp, xmm_size * 8);
85 }
86
87 if (handle_gpr) {
88 __ pop_IU_state();
89 }
90 }
91
92 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
93 Register src, Register dst, Register count) {
94
95 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
96
97 if (is_reference_type(type)) {
98 if (ShenandoahCardBarrier) {
99 bool checkcast = (decorators & ARRAYCOPY_CHECKCAST) != 0;
100 bool disjoint = (decorators & ARRAYCOPY_DISJOINT) != 0;
101 bool obj_int = (type == T_OBJECT) && UseCompressedOops;
102
103 // We need to save the original element count because the array copy stub
104 // will destroy the value and we need it for the card marking barrier.
105 if (!checkcast) {
106 if (!obj_int) {
107 // Save count for barrier
108 __ movptr(r11, count);
109 } else if (disjoint) {
110 // Save dst in r11 in the disjoint case
111 __ movq(r11, dst);
112 }
113 }
114 }
115
116 if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) {
117 Register thread = r15_thread;
118 assert_different_registers(src, dst, count, thread);
119
120 Label L_done;
121 // Short-circuit if count == 0.
122 __ testptr(count, count);
123 __ jcc(Assembler::zero, L_done);
124
125 // Avoid runtime call when not active.
126 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
127 int flags;
128 if (ShenandoahSATBBarrier && dest_uninitialized) {
129 flags = ShenandoahHeap::HAS_FORWARDED;
130 } else {
131 flags = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING;
132 }
133 __ testb(gc_state, flags);
134 __ jcc(Assembler::zero, L_done);
135
136 save_machine_state(masm, /* handle_gpr = */ true, /* handle_fp = */ false);
137
138 assert(src == rdi, "expected");
139 assert(dst == rsi, "expected");
140 assert(count == rdx, "expected");
141 if (UseCompressedOops) {
142 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_narrow_oop),
143 src, dst, count);
144 } else {
145 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_oop),
146 src, dst, count);
147 }
148
149 restore_machine_state(masm, /* handle_gpr = */ true, /* handle_fp = */ false);
150
151 __ bind(L_done);
152 }
153 }
154
155 }
156
157 void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
158 Register src, Register dst, Register count) {
159
160 if (ShenandoahCardBarrier && is_reference_type(type)) {
161 bool checkcast = (decorators & ARRAYCOPY_CHECKCAST) != 0;
162 bool disjoint = (decorators & ARRAYCOPY_DISJOINT) != 0;
163 bool obj_int = (type == T_OBJECT) && UseCompressedOops;
164 Register tmp = rax;
165
166 if (!checkcast) {
167 if (!obj_int) {
168 // Save count for barrier
169 count = r11;
170 } else if (disjoint) {
171 // Use the saved dst in the disjoint case
172 dst = r11;
173 }
174 } else {
175 tmp = rscratch1;
176 }
177 gen_write_ref_array_post_barrier(masm, decorators, dst, count, tmp);
178 }
179 }
180
181 void ShenandoahBarrierSetAssembler::satb_barrier(MacroAssembler* masm,
182 Register obj,
183 Register pre_val,
184 Register tmp,
185 bool tosca_live,
186 bool expand_call) {
187 assert(ShenandoahSATBBarrier, "Should be checked by caller");
188
189 // If expand_call is true then we expand the call_VM_leaf macro
190 // directly to skip generating the check by
191 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
192
193 const Register thread = r15_thread;
194
195 Label done;
196 Label runtime;
197
198 assert(pre_val != noreg, "check this code");
199
200 if (obj != noreg) {
201 assert_different_registers(obj, pre_val, tmp);
202 assert(pre_val != rax, "check this code");
203 }
204
205 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
206 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
207
208 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
209 __ testb(gc_state, ShenandoahHeap::MARKING);
210 __ jcc(Assembler::zero, done);
211
212 // Do we need to load the previous value?
213 if (obj != noreg) {
214 __ load_heap_oop(pre_val, Address(obj, 0), noreg, AS_RAW);
215 }
216
217 // Is the previous value null?
218 __ cmpptr(pre_val, NULL_WORD);
219 __ jcc(Assembler::equal, done);
220
221 // Can we store original value in the thread's buffer?
222 // Is index == 0?
223 // (The index field is typed as size_t.)
224
225 __ movptr(tmp, index); // tmp := *index_adr
226 __ cmpptr(tmp, 0); // tmp == 0?
227 __ jcc(Assembler::equal, runtime); // If yes, goto runtime
228
229 __ subptr(tmp, wordSize); // tmp := tmp - wordSize
230 __ movptr(index, tmp); // *index_adr := tmp
231 __ addptr(tmp, buffer); // tmp := tmp + *buffer_adr
232
233 // Record the previous value
234 __ movptr(Address(tmp, 0), pre_val);
235 __ jmp(done);
236
237 __ bind(runtime);
238 // save the live input values
239 if(tosca_live) __ push(rax);
240
241 if (obj != noreg && obj != rax)
242 __ push(obj);
243
244 if (pre_val != rax)
245 __ push(pre_val);
246
247 // Calling the runtime using the regular call_VM_leaf mechanism generates
248 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
249 // that checks that the *(ebp+frame::interpreter_frame_last_sp) == nullptr.
250 //
251 // If we care generating the pre-barrier without a frame (e.g. in the
252 // intrinsified Reference.get() routine) then ebp might be pointing to
253 // the caller frame and so this check will most likely fail at runtime.
254 //
255 // Expanding the call directly bypasses the generation of the check.
256 // So when we do not have have a full interpreter frame on the stack
257 // expand_call should be passed true.
258
259 // We move pre_val into c_rarg0 early, in order to avoid smashing it, should
260 // pre_val be c_rarg1 (where the call prologue would copy thread argument).
261 // Note: this should not accidentally smash thread, because thread is always r15.
262 assert(thread != c_rarg0, "smashed arg");
263 if (c_rarg0 != pre_val) {
264 __ mov(c_rarg0, pre_val);
265 }
266
267 if (expand_call) {
268 assert(pre_val != c_rarg1, "smashed arg");
269 if (c_rarg1 != thread) {
270 __ mov(c_rarg1, thread);
271 }
272 // Already moved pre_val into c_rarg0 above
273 __ MacroAssembler::call_VM_leaf_base(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), 1);
274 } else {
275 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), c_rarg0);
276 }
277
278 // save the live input values
279 if (pre_val != rax)
280 __ pop(pre_val);
281
282 if (obj != noreg && obj != rax)
283 __ pop(obj);
284
285 if(tosca_live) __ pop(rax);
286
287 __ bind(done);
288 }
289
290 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm, Register dst, Address src, DecoratorSet decorators) {
291 assert(ShenandoahLoadRefBarrier, "Should be enabled");
292
293 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
294 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
295 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
296 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
297 bool is_narrow = UseCompressedOops && !is_native;
298
299 Label heap_stable, not_cset;
300
301 __ block_comment("load_reference_barrier { ");
302
303 // Check if GC is active
304 Register thread = r15_thread;
305
306 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
307 int flags = ShenandoahHeap::HAS_FORWARDED;
308 if (!is_strong) {
309 flags |= ShenandoahHeap::WEAK_ROOTS;
310 }
311 __ testb(gc_state, flags);
312 __ jcc(Assembler::zero, heap_stable);
313
314 Register tmp1 = noreg, tmp2 = noreg;
315 if (is_strong) {
316 // Test for object in cset
317 // Allocate temporary registers
318 for (int i = 0; i < 8; i++) {
319 Register r = as_Register(i);
320 if (r != rsp && r != rbp && r != dst && r != src.base() && r != src.index()) {
321 if (tmp1 == noreg) {
322 tmp1 = r;
323 } else {
324 tmp2 = r;
325 break;
326 }
327 }
328 }
329 assert(tmp1 != noreg, "tmp1 allocated");
330 assert(tmp2 != noreg, "tmp2 allocated");
331 assert_different_registers(tmp1, tmp2, src.base(), src.index());
332 assert_different_registers(tmp1, tmp2, dst);
333
334 __ push(tmp1);
335 __ push(tmp2);
336
337 // Optimized cset-test
338 __ movptr(tmp1, dst);
339 __ shrptr(tmp1, ShenandoahHeapRegion::region_size_bytes_shift_jint());
340 __ movptr(tmp2, (intptr_t) ShenandoahHeap::in_cset_fast_test_addr());
341 __ movbool(tmp1, Address(tmp1, tmp2, Address::times_1));
342 __ testbool(tmp1);
343 __ jcc(Assembler::zero, not_cset);
344 }
345
346 save_machine_state(masm, /* handle_gpr = */ false, /* handle_fp = */ true);
347
348 // The rest is saved with the optimized path
349
350 uint num_saved_regs = 4 + (dst != rax ? 1 : 0) + 4 + (UseAPX ? 16 : 0);
351 __ subptr(rsp, num_saved_regs * wordSize);
352 uint slot = num_saved_regs;
353 if (dst != rax) {
354 __ movptr(Address(rsp, (--slot) * wordSize), rax);
355 }
356 __ movptr(Address(rsp, (--slot) * wordSize), rcx);
357 __ movptr(Address(rsp, (--slot) * wordSize), rdx);
358 __ movptr(Address(rsp, (--slot) * wordSize), rdi);
359 __ movptr(Address(rsp, (--slot) * wordSize), rsi);
360 __ movptr(Address(rsp, (--slot) * wordSize), r8);
361 __ movptr(Address(rsp, (--slot) * wordSize), r9);
362 __ movptr(Address(rsp, (--slot) * wordSize), r10);
363 __ movptr(Address(rsp, (--slot) * wordSize), r11);
364 // Save APX extended registers r16–r31 if enabled
365 if (UseAPX) {
366 __ movptr(Address(rsp, (--slot) * wordSize), r16);
367 __ movptr(Address(rsp, (--slot) * wordSize), r17);
368 __ movptr(Address(rsp, (--slot) * wordSize), r18);
369 __ movptr(Address(rsp, (--slot) * wordSize), r19);
370 __ movptr(Address(rsp, (--slot) * wordSize), r20);
371 __ movptr(Address(rsp, (--slot) * wordSize), r21);
372 __ movptr(Address(rsp, (--slot) * wordSize), r22);
373 __ movptr(Address(rsp, (--slot) * wordSize), r23);
374 __ movptr(Address(rsp, (--slot) * wordSize), r24);
375 __ movptr(Address(rsp, (--slot) * wordSize), r25);
376 __ movptr(Address(rsp, (--slot) * wordSize), r26);
377 __ movptr(Address(rsp, (--slot) * wordSize), r27);
378 __ movptr(Address(rsp, (--slot) * wordSize), r28);
379 __ movptr(Address(rsp, (--slot) * wordSize), r29);
380 __ movptr(Address(rsp, (--slot) * wordSize), r30);
381 __ movptr(Address(rsp, (--slot) * wordSize), r31);
382 }
383 // r12-r15 are callee saved in all calling conventions
384 assert(slot == 0, "must use all slots");
385
386 // Shuffle registers such that dst is in c_rarg0 and addr in c_rarg1.
387 Register arg0 = c_rarg0, arg1 = c_rarg1;
388 if (dst == arg1) {
389 __ lea(arg0, src);
390 __ xchgptr(arg1, arg0);
391 } else {
392 __ lea(arg1, src);
393 __ movptr(arg0, dst);
394 }
395
396 if (is_strong) {
397 if (is_narrow) {
398 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow), arg0, arg1);
399 } else {
400 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong), arg0, arg1);
401 }
402 } else if (is_weak) {
403 if (is_narrow) {
404 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow), arg0, arg1);
405 } else {
406 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak), arg0, arg1);
407 }
408 } else {
409 assert(is_phantom, "only remaining strength");
410 assert(!is_narrow, "phantom access cannot be narrow");
411 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom), arg0, arg1);
412 }
413
414 // Restore APX extended registers r31–r16 if previously saved
415 if (UseAPX) {
416 __ movptr(r31, Address(rsp, (slot++) * wordSize));
417 __ movptr(r30, Address(rsp, (slot++) * wordSize));
418 __ movptr(r29, Address(rsp, (slot++) * wordSize));
419 __ movptr(r28, Address(rsp, (slot++) * wordSize));
420 __ movptr(r27, Address(rsp, (slot++) * wordSize));
421 __ movptr(r26, Address(rsp, (slot++) * wordSize));
422 __ movptr(r25, Address(rsp, (slot++) * wordSize));
423 __ movptr(r24, Address(rsp, (slot++) * wordSize));
424 __ movptr(r23, Address(rsp, (slot++) * wordSize));
425 __ movptr(r22, Address(rsp, (slot++) * wordSize));
426 __ movptr(r21, Address(rsp, (slot++) * wordSize));
427 __ movptr(r20, Address(rsp, (slot++) * wordSize));
428 __ movptr(r19, Address(rsp, (slot++) * wordSize));
429 __ movptr(r18, Address(rsp, (slot++) * wordSize));
430 __ movptr(r17, Address(rsp, (slot++) * wordSize));
431 __ movptr(r16, Address(rsp, (slot++) * wordSize));
432 }
433 __ movptr(r11, Address(rsp, (slot++) * wordSize));
434 __ movptr(r10, Address(rsp, (slot++) * wordSize));
435 __ movptr(r9, Address(rsp, (slot++) * wordSize));
436 __ movptr(r8, Address(rsp, (slot++) * wordSize));
437 __ movptr(rsi, Address(rsp, (slot++) * wordSize));
438 __ movptr(rdi, Address(rsp, (slot++) * wordSize));
439 __ movptr(rdx, Address(rsp, (slot++) * wordSize));
440 __ movptr(rcx, Address(rsp, (slot++) * wordSize));
441
442 if (dst != rax) {
443 __ movptr(dst, rax);
444 __ movptr(rax, Address(rsp, (slot++) * wordSize));
445 }
446
447 assert(slot == num_saved_regs, "must use all slots");
448 __ addptr(rsp, num_saved_regs * wordSize);
449
450 restore_machine_state(masm, /* handle_gpr = */ false, /* handle_fp = */ true);
451
452 __ bind(not_cset);
453
454 if (is_strong) {
455 __ pop(tmp2);
456 __ pop(tmp1);
457 }
458
459 __ bind(heap_stable);
460
461 __ block_comment("} load_reference_barrier");
462 }
463
464 //
465 // Arguments:
466 //
467 // Inputs:
468 // src: oop location, might be clobbered
469 // tmp1: scratch register, might not be valid.
470 //
471 // Output:
472 // dst: oop loaded from src location
473 //
474 // Kill:
475 // tmp1 (if it is valid)
476 //
477 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
478 Register dst, Address src, Register tmp1) {
479 // 1: non-reference load, no additional barrier is needed
480 if (!is_reference_type(type)) {
481 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1);
482 return;
483 }
484
485 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Not expected");
486
487 // 2: load a reference from src location and apply LRB if needed
488 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
489 Register result_dst = dst;
490 bool use_tmp1_for_dst = false;
491
492 // Preserve src location for LRB
493 if (dst == src.base() || dst == src.index()) {
494 // Use tmp1 for dst if possible, as it is not used in BarrierAssembler::load_at()
495 if (tmp1->is_valid() && tmp1 != src.base() && tmp1 != src.index()) {
496 dst = tmp1;
497 use_tmp1_for_dst = true;
498 } else {
499 dst = rdi;
500 __ push(dst);
501 }
502 assert_different_registers(dst, src.base(), src.index());
503 }
504
505 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1);
506
507 load_reference_barrier(masm, dst, src, decorators);
508
509 // Move loaded oop to final destination
510 if (dst != result_dst) {
511 __ movptr(result_dst, dst);
512
513 if (!use_tmp1_for_dst) {
514 __ pop(dst);
515 }
516
517 dst = result_dst;
518 }
519 } else {
520 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1);
521 }
522
523 // 3: apply keep-alive barrier if needed
524 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
525 save_machine_state(masm, /* handle_gpr = */ true, /* handle_fp = */ true);
526
527 assert_different_registers(dst, tmp1, r15_thread);
528 // Generate the SATB pre-barrier code to log the value of
529 // the referent field in an SATB buffer.
530 satb_barrier(masm /* masm */,
531 noreg /* obj */,
532 dst /* pre_val */,
533 tmp1 /* tmp */,
534 true /* tosca_live */,
535 true /* expand_call */);
536
537 restore_machine_state(masm, /* handle_gpr = */ true, /* handle_fp = */ true);
538 }
539 }
540
541 void ShenandoahBarrierSetAssembler::card_barrier(MacroAssembler* masm, Register obj) {
542 assert(ShenandoahCardBarrier, "Should have been checked by caller");
543
544 // Does a store check for the oop in register obj. The content of
545 // register obj is destroyed afterwards.
546 __ shrptr(obj, CardTable::card_shift());
547
548 // We'll use this register as the TLS base address and also later on
549 // to hold the byte_map_base.
550 Register thread = r15_thread;
551 Register tmp = rscratch1;
552
553 Address curr_ct_holder_addr(thread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
554 __ movptr(tmp, curr_ct_holder_addr);
555 Address card_addr(tmp, obj, Address::times_1);
556
557 int dirty = CardTable::dirty_card_val();
558 if (UseCondCardMark) {
559 Label L_already_dirty;
560 __ cmpb(card_addr, dirty);
561 __ jccb(Assembler::equal, L_already_dirty);
562 __ movb(card_addr, dirty);
563 __ bind(L_already_dirty);
564 } else {
565 __ movb(card_addr, dirty);
566 }
567 }
568
569 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
570 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
571
572 // 1: non-reference types require no barriers
573 if (!is_reference_type(type)) {
574 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2, tmp3);
575 return;
576 }
577
578 // Flatten object address right away for simplicity: likely needed by barriers
579 assert_different_registers(val, tmp1, tmp2, tmp3, r15_thread);
580 if (dst.index() == noreg && dst.disp() == 0) {
581 if (dst.base() != tmp1) {
582 __ movptr(tmp1, dst.base());
583 }
584 } else {
585 __ lea(tmp1, dst);
586 }
587
588 bool storing_non_null = (val != noreg);
589
590 // 2: pre-barrier: SATB needs the previous value
591 if (ShenandoahBarrierSet::need_satb_barrier(decorators, type)) {
592 satb_barrier(masm,
593 tmp1 /* obj */,
594 tmp2 /* pre_val */,
595 tmp3 /* tmp */,
596 storing_non_null /* tosca_live */,
597 false /* expand_call */);
598 }
599
600 // Store!
601 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp1, 0), val, noreg, noreg, noreg);
602
603 // 3: post-barrier: card barrier needs store address
604 if (ShenandoahBarrierSet::need_card_barrier(decorators, type) && storing_non_null) {
605 card_barrier(masm, tmp1);
606 }
607 }
608
609 void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
610 Register obj, Register tmp, Label& slowpath) {
611 Label done;
612 // Resolve jobject
613 BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath);
614
615 // Check for null.
616 __ testptr(obj, obj);
617 __ jcc(Assembler::zero, done);
618
619 Address gc_state(jni_env, ShenandoahThreadLocalData::gc_state_offset() - JavaThread::jni_environment_offset());
620 __ testb(gc_state, ShenandoahHeap::EVACUATION);
621 __ jccb(Assembler::notZero, slowpath);
622 __ bind(done);
623 }
624
625 #ifdef COMPILER2
626 void ShenandoahBarrierSetAssembler::try_resolve_weak_handle_in_c2(MacroAssembler* masm, Register obj, Label& slowpath) {
627 Label done;
628
629 // Resolve weak handle using the standard implementation.
630 BarrierSetAssembler::try_resolve_weak_handle_in_c2(masm, obj, slowpath);
631
632 // Check if the reference is null, and if it is, take the fast path.
633 __ testptr(obj, obj);
634 __ jcc(Assembler::zero, done);
635
636 Address gc_state(r15_thread, ShenandoahThreadLocalData::gc_state_offset());
637
638 // Check if the heap is under weak-reference/roots processing, in
639 // which case we need to take the slow path.
640 __ testb(gc_state, ShenandoahHeap::WEAK_ROOTS);
641 __ jcc(Assembler::notZero, slowpath);
642 __ bind(done);
643 }
644 #endif // COMPILER2
645
646 // Special Shenandoah CAS implementation that handles false negatives
647 // due to concurrent evacuation.
648 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm,
649 Register res, Address addr, Register oldval, Register newval,
650 bool exchange, Register tmp1, Register tmp2) {
651 assert(ShenandoahCASBarrier, "Should only be used when CAS barrier is enabled");
652 assert(oldval == rax, "must be in rax for implicit use in cmpxchg");
653 assert_different_registers(oldval, tmp1, tmp2);
654 assert_different_registers(newval, tmp1, tmp2);
655
656 Label L_success, L_failure;
657
658 // Remember oldval for retry logic below
659 if (UseCompressedOops) {
660 __ movl(tmp1, oldval);
661 } else {
662 __ movptr(tmp1, oldval);
663 }
664
665 // Step 1. Fast-path.
666 //
667 // Try to CAS with given arguments. If successful, then we are done.
668
669 if (UseCompressedOops) {
670 __ lock();
671 __ cmpxchgl(newval, addr);
672 } else {
673 __ lock();
674 __ cmpxchgptr(newval, addr);
675 }
676 __ jcc(Assembler::equal, L_success);
677
678 // Step 2. CAS had failed. This may be a false negative.
679 //
680 // The trouble comes when we compare the to-space pointer with the from-space
681 // pointer to the same object. To resolve this, it will suffice to resolve
682 // the value from memory -- this will give both to-space pointers.
683 // If they mismatch, then it was a legitimate failure.
684 //
685 // Before reaching to resolve sequence, see if we can avoid the whole shebang
686 // with filters.
687
688 // Filter: when offending in-memory value is null, the failure is definitely legitimate
689 __ testptr(oldval, oldval);
690 __ jcc(Assembler::zero, L_failure);
691
692 // Filter: when heap is stable, the failure is definitely legitimate
693 const Register thread = r15_thread;
694 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
695 __ testb(gc_state, ShenandoahHeap::HAS_FORWARDED);
696 __ jcc(Assembler::zero, L_failure);
697
698 if (UseCompressedOops) {
699 __ movl(tmp2, oldval);
700 __ decode_heap_oop(tmp2);
701 } else {
702 __ movptr(tmp2, oldval);
703 }
704
705 // Decode offending in-memory value.
706 // Test if-forwarded
707 __ testb(Address(tmp2, oopDesc::mark_offset_in_bytes()), markWord::marked_value);
708 __ jcc(Assembler::noParity, L_failure); // When odd number of bits, then not forwarded
709 __ jcc(Assembler::zero, L_failure); // When it is 00, then also not forwarded
710
711 // Load and mask forwarding pointer
712 __ movptr(tmp2, Address(tmp2, oopDesc::mark_offset_in_bytes()));
713 __ shrptr(tmp2, 2);
714 __ shlptr(tmp2, 2);
715
716 if (UseCompressedOops) {
717 __ decode_heap_oop(tmp1); // decode for comparison
718 }
719
720 // Now we have the forwarded offender in tmp2.
721 // Compare and if they don't match, we have legitimate failure
722 __ cmpptr(tmp1, tmp2);
723 __ jcc(Assembler::notEqual, L_failure);
724
725 // Step 3. Need to fix the memory ptr before continuing.
726 //
727 // At this point, we have from-space oldval in the register, and its to-space
728 // address is in tmp2. Let's try to update it into memory. We don't care if it
729 // succeeds or not. If it does, then the retrying CAS would see it and succeed.
730 // If this fixup fails, this means somebody else beat us to it, and necessarily
731 // with to-space ptr store. We still have to do the retry, because the GC might
732 // have updated the reference for us.
733
734 if (UseCompressedOops) {
735 __ encode_heap_oop(tmp2); // previously decoded at step 2.
736 }
737
738 if (UseCompressedOops) {
739 __ lock();
740 __ cmpxchgl(tmp2, addr);
741 } else {
742 __ lock();
743 __ cmpxchgptr(tmp2, addr);
744 }
745
746 // Step 4. Try to CAS again.
747 //
748 // This is guaranteed not to have false negatives, because oldval is definitely
749 // to-space, and memory pointer is to-space as well. Nothing is able to store
750 // from-space ptr into memory anymore. Make sure oldval is restored, after being
751 // garbled during retries.
752 //
753 if (UseCompressedOops) {
754 __ movl(oldval, tmp2);
755 } else {
756 __ movptr(oldval, tmp2);
757 }
758
759 if (UseCompressedOops) {
760 __ lock();
761 __ cmpxchgl(newval, addr);
762 } else {
763 __ lock();
764 __ cmpxchgptr(newval, addr);
765 }
766 if (!exchange) {
767 __ jccb(Assembler::equal, L_success); // fastpath, peeking into Step 5, no need to jump
768 }
769
770 // Step 5. If we need a boolean result out of CAS, set the flag appropriately.
771 // and promote the result. Note that we handle the flag from both the 1st and 2nd CAS.
772 // Otherwise, failure witness for CAE is in oldval on all paths, and we can return.
773
774 if (exchange) {
775 __ bind(L_failure);
776 __ bind(L_success);
777 } else {
778 assert(res != noreg, "need result register");
779
780 Label exit;
781 __ bind(L_failure);
782 __ xorptr(res, res);
783 __ jmpb(exit);
784
785 __ bind(L_success);
786 __ movptr(res, 1);
787 __ bind(exit);
788 }
789 }
790
791 #ifdef PRODUCT
792 #define BLOCK_COMMENT(str) /* nothing */
793 #else
794 #define BLOCK_COMMENT(str) __ block_comment(str)
795 #endif
796
797 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
798
799 #define TIMES_OOP (UseCompressedOops ? Address::times_4 : Address::times_8)
800
801 void ShenandoahBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
802 Register addr, Register count,
803 Register tmp) {
804 assert(ShenandoahCardBarrier, "Should have been checked by caller");
805
806 Label L_loop, L_done;
807 const Register end = count;
808 assert_different_registers(addr, end);
809
810 // Zero count? Nothing to do.
811 __ testl(count, count);
812 __ jccb(Assembler::zero, L_done);
813
814 const Register thread = r15_thread;
815 Address curr_ct_holder_addr(thread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
816 __ movptr(tmp, curr_ct_holder_addr);
817
818 __ leaq(end, Address(addr, count, TIMES_OOP, 0)); // end == addr+count*oop_size
819 __ subptr(end, BytesPerHeapOop); // end - 1 to make inclusive
820 __ shrptr(addr, CardTable::card_shift());
821 __ shrptr(end, CardTable::card_shift());
822 __ subptr(end, addr); // end --> cards count
823
824 __ addptr(addr, tmp);
825
826 __ BIND(L_loop);
827 __ movb(Address(addr, count, Address::times_1), 0);
828 __ decrement(count);
829 __ jccb(Assembler::greaterEqual, L_loop);
830
831 __ BIND(L_done);
832 }
833
834 #undef __
835
836 #ifdef COMPILER1
837
838 #define __ ce->masm()->
839
840 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) {
841 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
842 // At this point we know that marking is in progress.
843 // If do_load() is true then we have to emit the
844 // load of the previous value; otherwise it has already
845 // been loaded into _pre_val.
846
847 __ bind(*stub->entry());
848 assert(stub->pre_val()->is_register(), "Precondition.");
849
850 Register pre_val_reg = stub->pre_val()->as_register();
851
852 if (stub->do_load()) {
853 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/);
854 }
855
856 __ cmpptr(pre_val_reg, NULL_WORD);
857 __ jcc(Assembler::equal, *stub->continuation());
858 ce->store_parameter(stub->pre_val()->as_register(), 0);
859 __ call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
860 __ jmp(*stub->continuation());
861
862 }
863
864 void ShenandoahBarrierSetAssembler::gen_load_reference_barrier_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
865 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
866 __ bind(*stub->entry());
867
868 DecoratorSet decorators = stub->decorators();
869 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
870 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
871 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
872 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
873
874 Register obj = stub->obj()->as_register();
875 Register res = stub->result()->as_register();
876 Register addr = stub->addr()->as_pointer_register();
877 Register tmp1 = stub->tmp1()->as_register();
878 Register tmp2 = stub->tmp2()->as_register();
879 assert_different_registers(obj, res, addr, tmp1, tmp2);
880
881 Label slow_path;
882
883 assert(res == rax, "result must arrive in rax");
884
885 if (res != obj) {
886 __ mov(res, obj);
887 }
888
889 if (is_strong) {
890 // Check for object being in the collection set.
891 __ mov(tmp1, res);
892 __ shrptr(tmp1, ShenandoahHeapRegion::region_size_bytes_shift_jint());
893 __ movptr(tmp2, (intptr_t) ShenandoahHeap::in_cset_fast_test_addr());
894 __ movbool(tmp2, Address(tmp2, tmp1, Address::times_1));
895 __ testbool(tmp2);
896 __ jcc(Assembler::zero, *stub->continuation());
897 }
898
899 __ bind(slow_path);
900 ce->store_parameter(res, 0);
901 ce->store_parameter(addr, 1);
902 if (is_strong) {
903 if (is_native) {
904 __ call(RuntimeAddress(bs->load_reference_barrier_strong_native_rt_code_blob()->code_begin()));
905 } else {
906 __ call(RuntimeAddress(bs->load_reference_barrier_strong_rt_code_blob()->code_begin()));
907 }
908 } else if (is_weak) {
909 __ call(RuntimeAddress(bs->load_reference_barrier_weak_rt_code_blob()->code_begin()));
910 } else {
911 assert(is_phantom, "only remaining strength");
912 __ call(RuntimeAddress(bs->load_reference_barrier_phantom_rt_code_blob()->code_begin()));
913 }
914 __ jmp(*stub->continuation());
915 }
916
917 #undef __
918
919 #define __ sasm->
920
921 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
922 __ prologue("shenandoah_pre_barrier", false);
923 // arg0 : previous value of memory
924
925 __ push(rax);
926 __ push(rdx);
927
928 const Register pre_val = rax;
929 const Register thread = r15_thread;
930 const Register tmp = rdx;
931
932 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
933 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
934
935 Label done;
936 Label runtime;
937
938 // Is SATB still active?
939 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
940 __ testb(gc_state, ShenandoahHeap::MARKING);
941 __ jcc(Assembler::zero, done);
942
943 // Can we store original value in the thread's buffer?
944
945 __ movptr(tmp, queue_index);
946 __ testptr(tmp, tmp);
947 __ jcc(Assembler::zero, runtime);
948 __ subptr(tmp, wordSize);
949 __ movptr(queue_index, tmp);
950 __ addptr(tmp, buffer);
951
952 // prev_val (rax)
953 __ load_parameter(0, pre_val);
954 __ movptr(Address(tmp, 0), pre_val);
955 __ jmp(done);
956
957 __ bind(runtime);
958
959 __ save_live_registers_no_oop_map(true);
960
961 // load the pre-value
962 __ load_parameter(0, rcx);
963 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), rcx);
964
965 __ restore_live_registers(true);
966
967 __ bind(done);
968
969 __ pop(rdx);
970 __ pop(rax);
971
972 __ epilogue();
973 }
974
975 void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_stub(StubAssembler* sasm, DecoratorSet decorators) {
976 __ prologue("shenandoah_load_reference_barrier", false);
977 // arg0 : object to be resolved
978
979 __ save_live_registers_no_oop_map(true);
980
981 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
982 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
983 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
984 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
985
986 __ load_parameter(0, c_rarg0);
987 __ load_parameter(1, c_rarg1);
988 if (is_strong) {
989 if (is_native) {
990 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong), c_rarg0, c_rarg1);
991 } else {
992 if (UseCompressedOops) {
993 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow), c_rarg0, c_rarg1);
994 } else {
995 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong), c_rarg0, c_rarg1);
996 }
997 }
998 } else if (is_weak) {
999 assert(!is_native, "weak must not be called off-heap");
1000 if (UseCompressedOops) {
1001 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow), c_rarg0, c_rarg1);
1002 } else {
1003 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak), c_rarg0, c_rarg1);
1004 }
1005 } else {
1006 assert(is_phantom, "only remaining strength");
1007 assert(is_native, "phantom must only be called off-heap");
1008 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom), c_rarg0, c_rarg1);
1009 }
1010
1011 __ restore_live_registers_except_rax(true);
1012
1013 __ epilogue();
1014 }
1015
1016 #undef __
1017
1018 #endif // COMPILER1
1019
1020 #ifdef COMPILER2
1021
1022 #undef __
1023 #define __ masm->
1024
1025 void ShenandoahBarrierSetAssembler::load_c2(const MachNode* node, MacroAssembler* masm, Register dst, Address src, bool narrow) {
1026 // Do the actual load. This load is the candidate for implicit null check, and MUST come first.
1027 if (narrow) {
1028 __ movl(dst, src);
1029 } else {
1030 __ movq(dst, src);
1031 }
1032
1033 // Post-barrier: LRB
1034 if (ShenandoahBarrierStubC2::needs_slow_barrier(node)) {
1035 ShenandoahBarrierStubC2* const stub = ShenandoahBarrierStubC2::create(node, dst, src, narrow, false);
1036 char check = 0;
1037 check |= ShenandoahBarrierStubC2::needs_keep_alive_barrier(node) ? ShenandoahHeap::MARKING : 0;
1038 check |= ShenandoahBarrierStubC2::needs_load_ref_barrier(node) ? ShenandoahHeap::HAS_FORWARDED : 0;
1039 check |= ShenandoahBarrierStubC2::needs_load_ref_barrier_weak(node) ? ShenandoahHeap::WEAK_ROOTS : 0;
1040 stub->enter_if_gc_state(*masm, check);
1041 }
1042 }
1043
1044 void ShenandoahBarrierSetAssembler::store_c2(const MachNode* node, MacroAssembler* masm,
1045 Address dst, bool dst_narrow,
1046 Register src, bool src_narrow,
1047 Register tmp) {
1048
1049 // Pre-barrier: SATB, keep-alive the current memory value.
1050 if (ShenandoahBarrierStubC2::needs_slow_barrier(node)) {
1051 assert(!ShenandoahBarrierStubC2::needs_load_ref_barrier(node), "Should not be required for stores");
1052 ShenandoahBarrierStubC2* const stub = ShenandoahBarrierStubC2::create(node, tmp, dst, dst_narrow, true);
1053 stub->enter_if_gc_state(*masm, ShenandoahHeap::MARKING);
1054 }
1055
1056 // Need to encode into tmp, because we cannot clobber src.
1057 // TODO: Maybe there is a matcher way to test that src is unused after this?
1058 if (dst_narrow && !src_narrow) {
1059 __ movq(tmp, src);
1060 if (ShenandoahBarrierStubC2::maybe_null(node)) {
1061 __ encode_heap_oop(tmp);
1062 } else {
1063 __ encode_heap_oop_not_null(tmp);
1064 }
1065 src = tmp;
1066 }
1067
1068 // Do the actual store
1069 if (dst_narrow) {
1070 __ movl(dst, src);
1071 } else {
1072 __ movq(dst, src);
1073 }
1074
1075 // Post-barrier: card updates.
1076 if (ShenandoahBarrierStubC2::needs_card_barrier(node)) {
1077 card_barrier_c2(masm, dst, tmp);
1078 }
1079 }
1080
1081 void ShenandoahBarrierSetAssembler::compare_and_set_c2(const MachNode* node, MacroAssembler* masm,
1082 Register res, Address addr,
1083 Register oldval, Register newval, Register tmp,
1084 bool narrow) {
1085
1086 assert(oldval == rax, "must be in rax for implicit use in cmpxchg");
1087
1088 // Oldval and newval can be in the same register, but all other registers should be
1089 // distinct for extra safety, as we shuffle register values around.
1090 assert_different_registers(oldval, tmp, addr.base(), addr.index());
1091 assert_different_registers(newval, tmp, addr.base(), addr.index());
1092
1093 // Pre-barrier covers several things:
1094 // a. Avoids false positives from CAS encountering to-space memory values.
1095 // b. Satisfies the need for LRB for the CAE result.
1096 // c. Records old value for the sake of SATB.
1097 //
1098 // (a) and (b) are covered because load barrier does memory location fixup.
1099 // (c) is covered by KA on the current memory value.
1100 if (ShenandoahBarrierStubC2::needs_slow_barrier(node)) {
1101 ShenandoahBarrierStubC2* const stub = ShenandoahBarrierStubC2::create(node, tmp, addr, narrow, true);
1102 char check = 0;
1103 check |= ShenandoahBarrierStubC2::needs_keep_alive_barrier(node) ? ShenandoahHeap::MARKING : 0;
1104 check |= ShenandoahBarrierStubC2::needs_load_ref_barrier(node) ? ShenandoahHeap::HAS_FORWARDED : 0;
1105 assert(!ShenandoahBarrierStubC2::needs_load_ref_barrier_weak(node), "Not supported for CAS");
1106 stub->enter_if_gc_state(*masm, check);
1107 }
1108
1109 // CAS!
1110 __ lock();
1111 if (narrow) {
1112 __ cmpxchgl(newval, addr);
1113 } else {
1114 __ cmpxchgptr(newval, addr);
1115 }
1116
1117 // If we need a boolean result out of CAS, set the flag appropriately and promote the result.
1118 if (res != noreg) {
1119 __ setcc(Assembler::equal, res);
1120 }
1121
1122 // Post-barrier deals with card updates.
1123 if (ShenandoahBarrierStubC2::needs_card_barrier(node)) {
1124 card_barrier_c2(masm, addr, tmp);
1125 }
1126 }
1127
1128 void ShenandoahBarrierSetAssembler::get_and_set_c2(const MachNode* node, MacroAssembler* masm, Register newval, Address addr, Register tmp, bool narrow) {
1129 assert_different_registers(newval, tmp, addr.base(), addr.index());
1130
1131 // Pre-barrier covers several things:
1132 // a. Satisfies the need for LRB for the GAS result.
1133 // b. Records old value for the sake of SATB.
1134 //
1135 // (a) is covered because load barrier does memory location fixup.
1136 // (b) is covered by KA on the current memory value.
1137 if (ShenandoahBarrierStubC2::needs_slow_barrier(node)) {
1138 ShenandoahBarrierStubC2* const stub = ShenandoahBarrierStubC2::create(node, tmp, addr, narrow, true);
1139 char check = 0;
1140 check |= ShenandoahBarrierStubC2::needs_keep_alive_barrier(node) ? ShenandoahHeap::MARKING : 0;
1141 check |= ShenandoahBarrierStubC2::needs_load_ref_barrier(node) ? ShenandoahHeap::HAS_FORWARDED : 0;
1142 assert(!ShenandoahBarrierStubC2::needs_load_ref_barrier_weak(node), "Not supported for GAS");
1143 stub->enter_if_gc_state(*masm, check);
1144 }
1145
1146 if (narrow) {
1147 __ xchgl(newval, addr);
1148 } else {
1149 __ xchgq(newval, addr);
1150 }
1151
1152 // Post-barrier deals with card updates.
1153 if (ShenandoahBarrierStubC2::needs_card_barrier(node)) {
1154 card_barrier_c2(masm, addr, tmp);
1155 }
1156 }
1157
1158 void ShenandoahBarrierSetAssembler::card_barrier_c2(MacroAssembler* masm, Address dst, Register tmp) {
1159 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
1160
1161 // TODO: Might be a good place to implement some filters here.
1162 // For example, G1 only flips card marks for stores within a single region.
1163
1164 __ lea(tmp, dst);
1165 __ shrptr(tmp, CardTable::card_shift());
1166 __ addptr(tmp, Address(r15_thread, in_bytes(ShenandoahThreadLocalData::card_table_offset())));
1167 Address card_address(tmp, 0);
1168
1169 assert(CardTable::dirty_card_val() == 0, "Encoding assumption");
1170 Label L_done;
1171 if (UseCondCardMark) {
1172 __ cmpb(card_address, 0);
1173 __ jccb(Assembler::equal, L_done);
1174 }
1175 if (UseCompressedOops && CompressedOops::base() == nullptr) {
1176 __ movb(card_address, r12);
1177 } else {
1178 __ movb(card_address, 0);
1179 }
1180 __ bind(L_done);
1181 }
1182
1183 #undef __
1184 #define __ masm.
1185
1186 void ShenandoahBarrierStubC2::enter_if_gc_state(MacroAssembler& masm, const char test_state) {
1187 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
1188
1189 Address gc_state_fast(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_offset()));
1190 __ testb(gc_state_fast, ShenandoahThreadLocalData::gc_state_to_fast(test_state));
1191 __ jcc(Assembler::notZero, *entry());
1192 __ bind(*continuation());
1193 }
1194
1195 void ShenandoahBarrierStubC2::emit_code(MacroAssembler& masm) {
1196 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
1197
1198 assert(_needs_keep_alive_barrier || _needs_load_ref_barrier, "Why are you here?");
1199
1200 __ align(InteriorEntryAlignment);
1201 __ bind(*entry());
1202
1203 // If we need to load ourselves, do it here.
1204 if (_do_load) {
1205 if (_narrow) {
1206 __ movl(_obj, _addr);
1207 } else {
1208 __ movq(_obj, _addr);
1209 }
1210 }
1211
1212 // If the object is null, there is no point in applying barriers.
1213 if (_narrow) {
1214 __ testl(_obj, _obj);
1215 } else {
1216 __ testptr(_obj, _obj);
1217 }
1218 __ jcc(Assembler::zero, *continuation());
1219
1220 // Barriers need temp to work, allocate one now.
1221 bool tmp_live;
1222 Register tmp = select_temp_register(tmp_live, _addr, _obj);
1223 if (tmp_live) {
1224 push_save_register(masm, tmp);
1225 }
1226
1227 // Go for barriers. Barriers can return straight to continuation, as long
1228 // as another barrier is not needed and tmp is not live.
1229 if (_needs_keep_alive_barrier) {
1230 keepalive(masm, _obj, tmp, (_needs_load_ref_barrier || tmp_live) ? nullptr : continuation());
1231 }
1232 if (_needs_load_ref_barrier) {
1233 lrb(masm, _obj, _addr, tmp, (tmp_live) ? nullptr : continuation());
1234 }
1235
1236 if (tmp_live) {
1237 pop_save_register(masm, tmp);
1238 __ jmp(*continuation());
1239 } else {
1240 #ifdef ASSERT
1241 __ hlt(); // Should not reach here
1242 #endif
1243 }
1244 }
1245
1246 void ShenandoahBarrierStubC2::keepalive(MacroAssembler& masm, Register obj, Register tmp, Label* L_done) {
1247 Address index(r15_thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
1248 Address buffer(r15_thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
1249
1250 Label L_through, L_fast, L_pack_and_done;
1251
1252 // If another barrier is enabled as well, do a runtime check for a specific barrier.
1253 if (_needs_load_ref_barrier) {
1254 Address gc_state(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
1255 __ testb(gc_state, ShenandoahHeap::MARKING);
1256 __ jcc(Assembler::zero, (L_done != nullptr) ? *L_done : L_through);
1257 }
1258
1259 // If object is narrow, we need to unpack it before inserting into buffer.
1260 if (_narrow) {
1261 __ decode_heap_oop_not_null(obj);
1262 }
1263
1264 // Check if buffer is already full. Go slow, if so.
1265 __ movptr(tmp, index);
1266 __ testptr(tmp, tmp);
1267 __ jcc(Assembler::notZero, L_fast);
1268
1269 // Slow-path: call runtime to handle.
1270 {
1271 // Shuffle in the arguments. The end result should be:
1272 // c_rarg0 <-- obj
1273 //
1274 // Save clobbered registers before overwriting them.
1275 bool clobbered_c_rarg0 = false;
1276 if (c_rarg0 != obj) {
1277 clobbered_c_rarg0 = push_save_register_if_live(masm, c_rarg0);
1278 __ mov(c_rarg0, obj);
1279 }
1280
1281 // Handle the rest there.
1282 if (!ShenandoahFasterRuntimeStubs || has_live_vector_registers()) {
1283 __ call(RuntimeAddress(keepalive_runtime_entry_addr(SaveMode::All)));
1284 } else if (has_save_space_for_live_gp_registers(clobbered_c_rarg0, false, false)) {
1285 save_live_gp_regs(masm, clobbered_c_rarg0, false, false);
1286 __ call(RuntimeAddress(keepalive_runtime_entry_addr(SaveMode::Nothing)));
1287 restore_live_gp_regs(masm, clobbered_c_rarg0, false, false);
1288 } else {
1289 __ call(RuntimeAddress(keepalive_runtime_entry_addr(SaveMode::GP)));
1290 }
1291
1292 // Restore the clobbered registers.
1293 if (clobbered_c_rarg0) {
1294 pop_save_register(masm, c_rarg0);
1295 }
1296 __ jmpb(L_pack_and_done);
1297 }
1298
1299 // Fast-path: put object into buffer.
1300 __ bind(L_fast);
1301 __ subptr(tmp, wordSize);
1302 __ movptr(index, tmp);
1303 __ addptr(tmp, buffer);
1304 __ movptr(Address(tmp, 0), obj);
1305
1306 // Exit here.
1307 __ bind(L_pack_and_done);
1308
1309 // Pack the object back if needed. We can skip this if we performed
1310 // the load ourselves: the value is not used by the caller.
1311 if (_narrow && !_do_load) {
1312 __ encode_heap_oop_not_null(obj);
1313 }
1314 if (L_done != nullptr) {
1315 __ jmp(*L_done);
1316 } else {
1317 // Fall-through
1318 __ bind(L_through);
1319 }
1320 }
1321
1322 void ShenandoahBarrierStubC2::lrb(MacroAssembler& masm, Register obj, Address addr, Register tmp, Label* L_done) {
1323 Label L_through, L_slow;
1324
1325 // If another barrier is enabled as well, do a runtime check for a specific barrier.
1326 if (_needs_keep_alive_barrier) {
1327 Address gc_state(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
1328 __ testb(gc_state, ShenandoahHeap::HAS_FORWARDED | (_needs_load_ref_weak_barrier ? ShenandoahHeap::WEAK_ROOTS : 0));
1329 __ jcc(Assembler::zero, (L_done != nullptr) ? *L_done : L_through);
1330 }
1331
1332 // If weak references are being processed, weak/phantom loads need to go slow,
1333 // regadless of their cset status.
1334 if (_needs_load_ref_weak_barrier) {
1335 Address gc_state(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
1336 __ testb(gc_state, ShenandoahHeap::WEAK_ROOTS);
1337 __ jccb(Assembler::notZero, L_slow);
1338 }
1339
1340 // Compute the cset bitmap index
1341 if (_narrow) {
1342 __ decode_heap_oop_not_null(tmp, obj);
1343 } else {
1344 __ movptr(tmp, obj);
1345 }
1346 __ shrptr(tmp, ShenandoahHeapRegion::region_size_bytes_shift_jint());
1347
1348 // If cset address is in good spot to just use it as offset. It almost always is.
1349 Address cset_addr_arg;
1350 intptr_t cset_addr = (intptr_t) ShenandoahHeap::in_cset_fast_test_addr();
1351 if ((cset_addr >> 3) < INT32_MAX) {
1352 assert(is_aligned(cset_addr, 8), "Sanity");
1353 cset_addr_arg = Address(tmp, checked_cast<int>(cset_addr >> 3), Address::times_8);
1354 } else {
1355 __ addptr(tmp, cset_addr);
1356 cset_addr_arg = Address(tmp, 0);
1357 }
1358
1359 // Cset-check. Fall-through to slow if in collection set.
1360 __ cmpb(cset_addr_arg, 0);
1361 __ jcc(Assembler::equal, (L_done != nullptr) ? *L_done : L_through);
1362
1363 // Slow path
1364 __ bind(L_slow);
1365 {
1366 assert_different_registers(rax, c_rarg0, c_rarg1);
1367
1368 // Shuffle in the arguments. The end result should be:
1369 // c_rarg0 <-- obj
1370 // c_rarg1 <-- lea(addr)
1371 //
1372 // Save clobbered registers before overwriting them, unless they
1373 // carry obj, which would be overwritten on return.
1374 bool clobbered_c_rarg0 = false;
1375 bool clobbered_c_rarg1 = false;
1376 bool clobbered_rax = false;
1377
1378 if (obj == c_rarg0) {
1379 clobbered_c_rarg1 = push_save_register_if_live(masm, c_rarg1);
1380 __ lea(c_rarg1, addr);
1381 } else if (obj == c_rarg1) {
1382 // Set up arguments in reverse, and then flip them
1383 clobbered_c_rarg0 = push_save_register_if_live(masm, c_rarg0);
1384 __ lea(c_rarg0, addr);
1385 __ xchgptr(c_rarg0, c_rarg1);
1386 } else {
1387 assert_different_registers(obj, c_rarg0, c_rarg1);
1388 clobbered_c_rarg0 = push_save_register_if_live(masm, c_rarg0);
1389 clobbered_c_rarg1 = push_save_register_if_live(masm, c_rarg1);
1390 __ lea(c_rarg1, addr);
1391 __ movptr(c_rarg0, obj);
1392 }
1393 if (obj != rax) {
1394 clobbered_rax = push_save_register_if_live(masm, rax);
1395 }
1396
1397 // Decode if needed.
1398 if (_narrow) {
1399 __ decode_heap_oop_not_null(c_rarg0);
1400 }
1401
1402 // Go to runtime stub and handle the rest there.
1403 if (!ShenandoahFasterRuntimeStubs || has_live_vector_registers()) {
1404 __ call(RuntimeAddress(lrb_runtime_entry_addr(SaveMode::All)));
1405 } else if (has_save_space_for_live_gp_registers(clobbered_c_rarg0, clobbered_c_rarg1, true)) {
1406 save_live_gp_regs(masm, clobbered_c_rarg0, clobbered_c_rarg1, true);
1407 __ call(RuntimeAddress(lrb_runtime_entry_addr(SaveMode::Nothing)));
1408 restore_live_gp_regs(masm, clobbered_c_rarg0, clobbered_c_rarg1, true);
1409 } else {
1410 __ call(RuntimeAddress(lrb_runtime_entry_addr(SaveMode::GP)));
1411 }
1412
1413 // Save the result where needed and restore the clobbered registers.
1414 if (obj != rax) {
1415 __ movptr(obj, rax);
1416 }
1417 // If object is narrow, we need to encode it before exiting.
1418 // For encoding, dst can only turn null if we are dealing with weak loads.
1419 // Otherwise, we have already null-checked. We can skip this if we performed
1420 // the load ourselves: the value is not used by the caller.
1421 if (_narrow && !_do_load) {
1422 if (_needs_load_ref_weak_barrier) {
1423 __ encode_heap_oop(obj);
1424 } else {
1425 __ encode_heap_oop_not_null(obj);
1426 }
1427 }
1428 if (clobbered_rax) {
1429 pop_save_register(masm, rax);
1430 }
1431 if (clobbered_c_rarg1) {
1432 pop_save_register(masm, c_rarg1);
1433 }
1434 if (clobbered_c_rarg0) {
1435 pop_save_register(masm, c_rarg0);
1436 }
1437 }
1438
1439 // Exit here
1440 if (L_done != nullptr) {
1441 __ jmp(*L_done);
1442 } else {
1443 // Fall-through.
1444 __ bind(L_through);
1445 }
1446 }
1447
1448 bool ShenandoahBarrierStubC2::has_live_vector_registers() {
1449 return _has_live_vector_registers;
1450 }
1451
1452 bool ShenandoahBarrierStubC2::is_live(Register reg) {
1453 return _live_gp.contains(reg);
1454 }
1455
1456 bool ShenandoahBarrierStubC2::has_save_space_for_live_gp_registers(bool skip_crarg0, bool skip_crarg1, bool skip_rax) {
1457 int c = 0;
1458 for (int i = 0; i < _live_gp.length(); i++) {
1459 Register r = _live_gp.at(i);
1460 if (skip_rax && (r == rax)) continue;
1461 if (skip_crarg0 && (r == c_rarg0)) continue;
1462 if (skip_crarg1 && (r == c_rarg1)) continue;
1463 c++;
1464 }
1465 return c <= (ShenandoahBarrierSetC2::bsc2()->reserved_slots() - _save_slots_idx);
1466 }
1467
1468 void ShenandoahBarrierStubC2::save_live_gp_regs(MacroAssembler& masm, bool skip_crarg0, bool skip_crarg1, bool skip_rax) {
1469 for (int i = 0; i < _live_gp.length(); i++) {
1470 Register r = _live_gp.at(i);
1471 if (skip_rax && (r == rax)) continue;
1472 if (skip_crarg0 && (r == c_rarg0)) continue;
1473 if (skip_crarg1 && (r == c_rarg1)) continue;
1474 push_save_register(masm, r);
1475 }
1476 }
1477
1478 void ShenandoahBarrierStubC2::restore_live_gp_regs(MacroAssembler& masm, bool skip_crarg0, bool skip_crarg1, bool skip_rax) {
1479 for (int i = _live_gp.length() - 1; i >= 0; i--) {
1480 Register r = _live_gp.at(i);
1481 if (skip_rax && (r == rax)) continue;
1482 if (skip_crarg0 && (r == c_rarg0)) continue;
1483 if (skip_crarg1 && (r == c_rarg1)) continue;
1484 pop_save_register(masm, r);
1485 }
1486 }
1487
1488 bool ShenandoahBarrierStubC2::push_save_register_if_live(MacroAssembler& masm, Register reg) {
1489 if (is_live(reg)) {
1490 push_save_register(masm, reg);
1491 return true;
1492 } else {
1493 return false;
1494 }
1495 }
1496
1497 void ShenandoahBarrierStubC2::push_save_register(MacroAssembler& masm, Register reg) {
1498 __ movptr(Address(rsp, push_save_slot()), reg);
1499 }
1500
1501 void ShenandoahBarrierStubC2::pop_save_register(MacroAssembler& masm, Register reg) {
1502 __ movptr(reg, Address(rsp, pop_save_slot()));
1503 }
1504
1505 Register ShenandoahBarrierStubC2::select_temp_register(bool& selected_live, Address addr, Register reg1) {
1506 Register tmp = noreg;
1507 Register fallback_live = noreg;
1508
1509 // Try to select non-live first:
1510 for (int i = 0; i < Register::available_gp_registers(); i++) {
1511 Register r = as_Register(i);
1512 if (r != rsp && r != rbp && r != r12_heapbase && r != r15_thread &&
1513 r != reg1 && r != addr.base() && r != addr.index()) {
1514 if (!is_live(r)) {
1515 tmp = r;
1516 break;
1517 } else if (fallback_live == noreg) {
1518 fallback_live = r;
1519 }
1520 }
1521 }
1522
1523 // If we could not find a non-live register, select the live fallback:
1524 if (tmp == noreg) {
1525 tmp = fallback_live;
1526 selected_live = true;
1527 } else {
1528 selected_live = false;
1529 }
1530
1531 assert(tmp != noreg, "successfully selected");
1532 assert_different_registers(tmp, reg1);
1533 assert_different_registers(tmp, addr.base());
1534 assert_different_registers(tmp, addr.index());
1535 return tmp;
1536 }
1537
1538 void ShenandoahBarrierStubC2::post_init(int offset) {
1539 // Precompute live registers.
1540 assert(_live_gp.is_empty(), "sanity: initial state");
1541 assert(!_has_live_vector_registers, "sanity: initial state");
1542 RegMaskIterator rmi(preserve_set());
1543 while (rmi.has_next()) {
1544 const OptoReg::Name opto_reg = rmi.next();
1545 const VMReg vm_reg = OptoReg::as_VMReg(opto_reg);
1546 if (vm_reg->is_Register()) {
1547 Register r = vm_reg->as_Register();
1548 if (r == rsp) continue;
1549 _live_gp.append_if_missing(r);
1550 } else if (vm_reg->is_KRegister()) {
1551 _has_live_vector_registers = true;
1552 } else if (vm_reg->is_XMMRegister()) {
1553 _has_live_vector_registers = true;
1554 } else {
1555 fatal("Unexpected register type");
1556 }
1557 }
1558 }
1559 #undef __
1560 #endif