1 /*
2 * Copyright (c) 2018, 2022, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
27 #include "gc/shenandoah/mode/shenandoahMode.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
30 #include "gc/shenandoah/shenandoahForwarding.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 #endif
47
48 #define __ masm->
49
50 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
51 Register src, Register dst, Register count, RegSet saved_regs) {
52 if (is_oop) {
53 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
54 if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) {
55
56 Label done;
57
58 // Avoid calling runtime if count == 0
59 __ cbz(count, done);
60
61 // Is GC active?
62 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
63 __ ldrb(rscratch1, gc_state);
64 if (ShenandoahSATBBarrier && dest_uninitialized) {
65 __ tbz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
66 } else {
67 __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING);
68 __ tst(rscratch1, rscratch2);
69 __ br(Assembler::EQ, done);
70 }
71
72 __ push(saved_regs, sp);
73 if (UseCompressedOops) {
74 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_narrow_oop), src, dst, count);
75 } else {
76 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_oop), src, dst, count);
77 }
78 __ pop(saved_regs, sp);
79 __ bind(done);
80 }
81 }
82 }
83
84 void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
85 Register start, Register count, Register tmp) {
86 if (ShenandoahCardBarrier && is_oop) {
87 gen_write_ref_array_post_barrier(masm, decorators, start, count, tmp);
88 }
89 }
90
91 void ShenandoahBarrierSetAssembler::shenandoah_write_barrier_pre(MacroAssembler* masm,
92 Register obj,
93 Register pre_val,
94 Register thread,
95 Register tmp,
96 bool tosca_live,
97 bool expand_call) {
98 if (ShenandoahSATBBarrier) {
99 satb_write_barrier_pre(masm, obj, pre_val, thread, tmp, rscratch1, tosca_live, expand_call);
100 }
101 }
102
103 void ShenandoahBarrierSetAssembler::satb_write_barrier_pre(MacroAssembler* masm,
104 Register obj,
105 Register pre_val,
106 Register thread,
107 Register tmp1,
108 Register tmp2,
109 bool tosca_live,
110 bool expand_call) {
111 // If expand_call is true then we expand the call_VM_leaf macro
112 // directly to skip generating the check by
113 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
114
115 assert(thread == rthread, "must be");
116
117 Label done;
118 Label runtime;
119
120 assert_different_registers(obj, pre_val, tmp1, tmp2);
121 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
122
123 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
124 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
125
126 // Is marking active?
127 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
128 __ ldrb(tmp1, gc_state);
129 __ tbz(tmp1, ShenandoahHeap::MARKING_BITPOS, done);
130
131 // Do we need to load the previous value?
132 if (obj != noreg) {
133 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
134 }
135
136 // Is the previous value null?
137 __ cbz(pre_val, done);
138
139 // Can we store original value in the thread's buffer?
140 // Is index == 0?
141 // (The index field is typed as size_t.)
142
143 __ ldr(tmp1, index); // tmp := *index_adr
144 __ cbz(tmp1, runtime); // tmp == 0?
145 // If yes, goto runtime
146
147 __ sub(tmp1, tmp1, wordSize); // tmp := tmp - wordSize
148 __ str(tmp1, index); // *index_adr := tmp
149 __ ldr(tmp2, buffer);
150 __ add(tmp1, tmp1, tmp2); // tmp := tmp + *buffer_adr
151
152 // Record the previous value
153 __ str(pre_val, Address(tmp1, 0));
154 __ b(done);
155
156 __ bind(runtime);
157 // save the live input values
158 RegSet saved = RegSet::of(pre_val);
159 if (tosca_live) saved += RegSet::of(r0);
160 if (obj != noreg) saved += RegSet::of(obj);
161
162 __ push(saved, sp);
163
164 // Calling the runtime using the regular call_VM_leaf mechanism generates
165 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
166 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == nullptr.
167 //
168 // If we care generating the pre-barrier without a frame (e.g. in the
169 // intrinsified Reference.get() routine) then rfp might be pointing to
170 // the caller frame and so this check will most likely fail at runtime.
171 //
172 // Expanding the call directly bypasses the generation of the check.
173 // So when we do not have have a full interpreter frame on the stack
174 // expand_call should be passed true.
175
176 if (expand_call) {
177 assert(pre_val != c_rarg1, "smashed arg");
178 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), pre_val);
179 } else {
180 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), pre_val);
181 }
182
183 __ pop(saved, sp);
184
185 __ bind(done);
186 }
187
188 void ShenandoahBarrierSetAssembler::resolve_forward_pointer(MacroAssembler* masm, Register dst, Register tmp) {
189 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
190 Label is_null;
191 __ cbz(dst, is_null);
192 resolve_forward_pointer_not_null(masm, dst, tmp);
193 __ bind(is_null);
194 }
195
196 // IMPORTANT: This must preserve all registers, even rscratch1 and rscratch2, except those explicitly
197 // passed in.
198 void ShenandoahBarrierSetAssembler::resolve_forward_pointer_not_null(MacroAssembler* masm, Register dst, Register tmp) {
199 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
200 // The below loads the mark word, checks if the lowest two bits are
201 // set, and if so, clear the lowest two bits and copy the result
202 // to dst. Otherwise it leaves dst alone.
203 // Implementing this is surprisingly awkward. I do it here by:
204 // - Inverting the mark word
205 // - Test lowest two bits == 0
206 // - If so, set the lowest two bits
207 // - Invert the result back, and copy to dst
208
209 bool borrow_reg = (tmp == noreg);
210 if (borrow_reg) {
211 // No free registers available. Make one useful.
212 tmp = rscratch1;
213 if (tmp == dst) {
214 tmp = rscratch2;
215 }
216 __ push(RegSet::of(tmp), sp);
217 }
218
219 assert_different_registers(tmp, dst);
220
221 Label done;
222 __ ldr(tmp, Address(dst, oopDesc::mark_offset_in_bytes()));
223 __ eon(tmp, tmp, zr);
224 __ ands(zr, tmp, markWord::lock_mask_in_place);
225 __ br(Assembler::NE, done);
226 __ orr(tmp, tmp, markWord::marked_value);
227 __ eon(dst, tmp, zr);
228 __ bind(done);
229
230 if (borrow_reg) {
231 __ pop(RegSet::of(tmp), sp);
232 }
233 }
234
235 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm, Register dst, Address load_addr, DecoratorSet decorators) {
236 assert(ShenandoahLoadRefBarrier, "Should be enabled");
237 assert(dst != rscratch2, "need rscratch2");
238 assert_different_registers(load_addr.base(), load_addr.index(), rscratch1, rscratch2);
239
240 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
241 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
242 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
243 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
244 bool is_narrow = UseCompressedOops && !is_native;
245
246 Label heap_stable, not_cset;
247 __ enter(/*strip_ret_addr*/true);
248 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
249 __ ldrb(rscratch2, gc_state);
250
251 // Check for heap stability
252 if (is_strong) {
253 __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, heap_stable);
254 } else {
255 Label lrb;
256 __ tbnz(rscratch2, ShenandoahHeap::WEAK_ROOTS_BITPOS, lrb);
257 __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, heap_stable);
258 __ bind(lrb);
259 }
260
261 // use r1 for load address
262 Register result_dst = dst;
263 if (dst == r1) {
264 __ mov(rscratch1, dst);
265 dst = rscratch1;
266 }
267
268 // Save r0 and r1, unless it is an output register
269 RegSet to_save = RegSet::of(r0, r1) - result_dst;
270 __ push(to_save, sp);
271 __ lea(r1, load_addr);
272 __ mov(r0, dst);
273
274 // Test for in-cset
275 if (is_strong) {
276 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr());
277 __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint());
278 __ ldrb(rscratch2, Address(rscratch2, rscratch1));
279 __ tbz(rscratch2, 0, not_cset);
280 }
281
282 __ push_call_clobbered_registers();
283 if (is_strong) {
284 if (is_narrow) {
285 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow));
286 } else {
287 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong));
288 }
289 } else if (is_weak) {
290 if (is_narrow) {
291 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow));
292 } else {
293 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak));
294 }
295 } else {
296 assert(is_phantom, "only remaining strength");
297 assert(!is_narrow, "phantom access cannot be narrow");
298 // AOT saved adapters need relocation for this call.
299 __ lea(lr, RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom)));
300 }
301 __ blr(lr);
302 __ mov(rscratch1, r0);
303 __ pop_call_clobbered_registers();
304 __ mov(r0, rscratch1);
305
306 __ bind(not_cset);
307
308 __ mov(result_dst, r0);
309 __ pop(to_save, sp);
310
311 __ bind(heap_stable);
312 __ leave();
313 }
314
315 //
316 // Arguments:
317 //
318 // Inputs:
319 // src: oop location to load from, might be clobbered
320 //
321 // Output:
322 // dst: oop loaded from src location
323 //
324 // Kill:
325 // rscratch1 (scratch reg)
326 //
327 // Alias:
328 // dst: rscratch1 (might use rscratch1 as temporary output register to avoid clobbering src)
329 //
330 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
331 Register dst, Address src, Register tmp1, Register tmp2) {
332 // 1: non-reference load, no additional barrier is needed
333 if (!is_reference_type(type)) {
334 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
335 return;
336 }
337
338 // 2: load a reference from src location and apply LRB if needed
339 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
340 Register result_dst = dst;
341
342 // Preserve src location for LRB
343 if (dst == src.base() || dst == src.index()) {
344 dst = rscratch1;
345 }
346 assert_different_registers(dst, src.base(), src.index());
347
348 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
349
350 load_reference_barrier(masm, dst, src, decorators);
351
352 if (dst != result_dst) {
353 __ mov(result_dst, dst);
354 dst = result_dst;
355 }
356 } else {
357 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
358 }
359
360 // 3: apply keep-alive barrier if needed
361 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
362 __ enter(/*strip_ret_addr*/true);
363 __ push_call_clobbered_registers();
364 satb_write_barrier_pre(masm /* masm */,
365 noreg /* obj */,
366 dst /* pre_val */,
367 rthread /* thread */,
368 tmp1 /* tmp1 */,
369 tmp2 /* tmp2 */,
370 true /* tosca_live */,
371 true /* expand_call */);
372 __ pop_call_clobbered_registers();
373 __ leave();
374 }
375 }
376
377 void ShenandoahBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj) {
378 assert(ShenandoahCardBarrier, "Should have been checked by caller");
379
380 __ lsr(obj, obj, CardTable::card_shift());
381
382 assert(CardTable::dirty_card_val() == 0, "must be");
383
384 Address curr_ct_holder_addr(rthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
385 __ ldr(rscratch1, curr_ct_holder_addr);
386
387 if (UseCondCardMark) {
388 Label L_already_dirty;
389 __ ldrb(rscratch2, Address(obj, rscratch1));
390 __ cbz(rscratch2, L_already_dirty);
391 __ strb(zr, Address(obj, rscratch1));
392 __ bind(L_already_dirty);
393 } else {
394 __ strb(zr, Address(obj, rscratch1));
395 }
396 }
397
398 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
399 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
400 bool on_oop = is_reference_type(type);
401 if (!on_oop) {
402 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2, tmp3);
403 return;
404 }
405
406 // flatten object address if needed
407 if (dst.index() == noreg && dst.offset() == 0) {
408 if (dst.base() != tmp3) {
409 __ mov(tmp3, dst.base());
410 }
411 } else {
412 __ lea(tmp3, dst);
413 }
414
415 shenandoah_write_barrier_pre(masm,
416 tmp3 /* obj */,
417 tmp2 /* pre_val */,
418 rthread /* thread */,
419 tmp1 /* tmp */,
420 val != noreg /* tosca_live */,
421 false /* expand_call */);
422
423 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), val, noreg, noreg, noreg);
424
425 bool in_heap = (decorators & IN_HEAP) != 0;
426 bool needs_post_barrier = (val != noreg) && in_heap && ShenandoahCardBarrier;
427 if (needs_post_barrier) {
428 store_check(masm, tmp3);
429 }
430 }
431
432 void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
433 Register obj, Register tmp, Label& slowpath) {
434 Label done;
435 // Resolve jobject
436 BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath);
437
438 // Check for null.
439 __ cbz(obj, done);
440
441 assert(obj != rscratch2, "need rscratch2");
442 Address gc_state(jni_env, ShenandoahThreadLocalData::gc_state_offset() - JavaThread::jni_environment_offset());
443 __ lea(rscratch2, gc_state);
444 __ ldrb(rscratch2, Address(rscratch2));
445
446 // Check for heap in evacuation phase
447 __ tbnz(rscratch2, ShenandoahHeap::EVACUATION_BITPOS, slowpath);
448
449 __ bind(done);
450 }
451
452 // Special Shenandoah CAS implementation that handles false negatives due
453 // to concurrent evacuation. The service is more complex than a
454 // traditional CAS operation because the CAS operation is intended to
455 // succeed if the reference at addr exactly matches expected or if the
456 // reference at addr holds a pointer to a from-space object that has
457 // been relocated to the location named by expected. There are two
458 // races that must be addressed:
459 // a) A parallel thread may mutate the contents of addr so that it points
460 // to a different object. In this case, the CAS operation should fail.
461 // b) A parallel thread may heal the contents of addr, replacing a
462 // from-space pointer held in addr with the to-space pointer
463 // representing the new location of the object.
464 // Upon entry to cmpxchg_oop, it is assured that new_val equals null
465 // or it refers to an object that is not being evacuated out of
466 // from-space, or it refers to the to-space version of an object that
467 // is being evacuated out of from-space.
468 //
469 // By default the value held in the result register following execution
470 // of the generated code sequence is 0 to indicate failure of CAS,
471 // non-zero to indicate success. If is_cae, the result is the value most
472 // recently fetched from addr rather than a boolean success indicator.
473 //
474 // Clobbers rscratch1, rscratch2
475 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm,
476 Register addr,
477 Register expected,
478 Register new_val,
479 bool acquire, bool release,
480 bool is_cae,
481 Register result) {
482 Register tmp1 = rscratch1;
483 Register tmp2 = rscratch2;
484 bool is_narrow = UseCompressedOops;
485 Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword;
486
487 assert_different_registers(addr, expected, tmp1, tmp2);
488 assert_different_registers(addr, new_val, tmp1, tmp2);
489
490 Label step4, done;
491
492 // There are two ways to reach this label. Initial entry into the
493 // cmpxchg_oop code expansion starts at step1 (which is equivalent
494 // to label step4). Additionally, in the rare case that four steps
495 // are required to perform the requested operation, the fourth step
496 // is the same as the first. On a second pass through step 1,
497 // control may flow through step 2 on its way to failure. It will
498 // not flow from step 2 to step 3 since we are assured that the
499 // memory at addr no longer holds a from-space pointer.
500 //
501 // The comments that immediately follow the step4 label apply only
502 // to the case in which control reaches this label by branch from
503 // step 3.
504
505 __ bind (step4);
506
507 // Step 4. CAS has failed because the value most recently fetched
508 // from addr is no longer the from-space pointer held in tmp2. If a
509 // different thread replaced the in-memory value with its equivalent
510 // to-space pointer, then CAS may still be able to succeed. The
511 // value held in the expected register has not changed.
512 //
513 // It is extremely rare we reach this point. For this reason, the
514 // implementation opts for smaller rather than potentially faster
515 // code. Ultimately, smaller code for this rare case most likely
516 // delivers higher overall throughput by enabling improved icache
517 // performance.
518
519 // Step 1. Fast-path.
520 //
521 // Try to CAS with given arguments. If successful, then we are done.
522 //
523 // No label required for step 1.
524
525 __ cmpxchg(addr, expected, new_val, size, acquire, release, false, tmp2);
526 // EQ flag set iff success. tmp2 holds value fetched.
527
528 // If expected equals null but tmp2 does not equal null, the
529 // following branches to done to report failure of CAS. If both
530 // expected and tmp2 equal null, the following branches to done to
531 // report success of CAS. There's no need for a special test of
532 // expected equal to null.
533
534 __ br(Assembler::EQ, done);
535 // if CAS failed, fall through to step 2
536
537 // Step 2. CAS has failed because the value held at addr does not
538 // match expected. This may be a false negative because the value fetched
539 // from addr (now held in tmp2) may be a from-space pointer to the
540 // original copy of same object referenced by to-space pointer expected.
541 //
542 // To resolve this, it suffices to find the forward pointer associated
543 // with fetched value. If this matches expected, retry CAS with new
544 // parameters. If this mismatches, then we have a legitimate
545 // failure, and we're done.
546 //
547 // No need for step2 label.
548
549 // overwrite tmp1 with from-space pointer fetched from memory
550 __ mov(tmp1, tmp2);
551
552 if (is_narrow) {
553 // Decode tmp1 in order to resolve its forward pointer
554 __ decode_heap_oop(tmp1, tmp1);
555 }
556 resolve_forward_pointer(masm, tmp1);
557 // Encode tmp1 to compare against expected.
558 __ encode_heap_oop(tmp1, tmp1);
559
560 // Does forwarded value of fetched from-space pointer match original
561 // value of expected? If tmp1 holds null, this comparison will fail
562 // because we know from step1 that expected is not null. There is
563 // no need for a separate test for tmp1 (the value originally held
564 // in memory) equal to null.
565 __ cmp(tmp1, expected);
566
567 // If not, then the failure was legitimate and we're done.
568 // Branching to done with NE condition denotes failure.
569 __ br(Assembler::NE, done);
570
571 // Fall through to step 3. No need for step3 label.
572
573 // Step 3. We've confirmed that the value originally held in memory
574 // (now held in tmp2) pointed to from-space version of original
575 // expected value. Try the CAS again with the from-space expected
576 // value. If it now succeeds, we're good.
577 //
578 // Note: tmp2 holds encoded from-space pointer that matches to-space
579 // object residing at expected. tmp2 is the new "expected".
580
581 // Note that macro implementation of __cmpxchg cannot use same register
582 // tmp2 for result and expected since it overwrites result before it
583 // compares result with expected.
584 __ cmpxchg(addr, tmp2, new_val, size, acquire, release, false, noreg);
585 // EQ flag set iff success. tmp2 holds value fetched, tmp1 (rscratch1) clobbered.
586
587 // If fetched value did not equal the new expected, this could
588 // still be a false negative because some other thread may have
589 // newly overwritten the memory value with its to-space equivalent.
590 __ br(Assembler::NE, step4);
591
592 if (is_cae) {
593 // We're falling through to done to indicate success. Success
594 // with is_cae is denoted by returning the value of expected as
595 // result.
596 __ mov(tmp2, expected);
597 }
598
599 __ bind(done);
600 // At entry to done, the Z (EQ) flag is on iff if the CAS
601 // operation was successful. Additionally, if is_cae, tmp2 holds
602 // the value most recently fetched from addr. In this case, success
603 // is denoted by tmp2 matching expected.
604
605 if (is_cae) {
606 __ mov(result, tmp2);
607 } else {
608 __ cset(result, Assembler::EQ);
609 }
610 }
611
612 #ifdef COMPILER2
613 void ShenandoahBarrierSetAssembler::load_ref_barrier_c2(const MachNode* node, MacroAssembler* masm, Register obj, Register addr, Register tmp, bool narrow, bool maybe_null) {
614 if (!ShenandoahLoadRefBarrierStubC2::needs_barrier(node)) {
615 return;
616 }
617 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
618 ShenandoahLoadRefBarrierStubC2* const stub = ShenandoahLoadRefBarrierStubC2::create(node, obj, addr, tmp, noreg, noreg, narrow);
619
620 // Don't preserve the obj across the runtime call, we override it from the return value anyway.
621 stub->dont_preserve(obj);
622
623 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
624 __ ldrb(rscratch1, gc_state);
625
626 // Check if GC marking is in progress or we are handling a weak reference, otherwise we don't have to do anything.
627 bool is_strong = (node->barrier_data() & ShenandoahBarrierStrong) != 0;
628 if (is_strong) {
629 __ tbnz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, *stub->entry());
630 } else {
631 static_assert(ShenandoahHeap::HAS_FORWARDED_BITPOS == 0, "Relied on in LRB check below.");
632 __ orr(tmp, rscratch1, rscratch1, Assembler::LSR, ShenandoahHeap::WEAK_ROOTS_BITPOS);
633 __ tbnz(tmp, ShenandoahHeap::HAS_FORWARDED_BITPOS, *stub->entry());
634 }
635
636 __ bind(*stub->continuation());
637 }
638
639 void ShenandoahBarrierSetAssembler::load_ref_barrier_c3(const MachNode* node, MacroAssembler* masm, Register obj, Register addr, Register tmp, bool narrow, bool maybe_null, Register gc_state) {
640 if (!ShenandoahLoadRefBarrierStubC2::needs_barrier(node)) {
641 return;
642 }
643 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
644 ShenandoahLoadRefBarrierStubC2* const stub = ShenandoahLoadRefBarrierStubC2::create(node, obj, addr, tmp, noreg, noreg, narrow);
645
646 // Don't preserve the obj across the runtime call, we override it from the return value anyway.
647 stub->dont_preserve(obj);
648
649 // Check if GC marking is in progress or we are handling a weak reference, otherwise we don't have to do anything.
650 bool is_strong = (node->barrier_data() & ShenandoahBarrierStrong) != 0;
651 if (is_strong) {
652 __ tbnz(gc_state, ShenandoahHeap::HAS_FORWARDED_BITPOS, *stub->entry());
653 } else {
654 static_assert(ShenandoahHeap::HAS_FORWARDED_BITPOS == 0, "Relied on in LRB check below.");
655 __ orr(tmp, gc_state, gc_state, Assembler::LSR, ShenandoahHeap::WEAK_ROOTS_BITPOS);
656 __ tbnz(tmp, ShenandoahHeap::HAS_FORWARDED_BITPOS, *stub->entry());
657 }
658
659 __ bind(*stub->continuation());
660 }
661
662 void ShenandoahBarrierSetAssembler::satb_barrier_c3(const MachNode* node, MacroAssembler* masm, Register addr, Register pre_val, Register gc_state) {
663 assert_different_registers(addr, pre_val);
664 if (!ShenandoahSATBBarrierStubC2::needs_barrier(node)) {
665 return;
666 }
667
668 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
669 ShenandoahSATBBarrierStubC2* const stub = ShenandoahSATBBarrierStubC2::create(node, addr, pre_val);
670
671 // Check if GC marking is in progress, otherwise we don't have to do anything.
672 __ tstw(gc_state, ShenandoahHeap::MARKING);
673 __ br(Assembler::NE, *stub->entry());
674 __ bind(*stub->continuation());
675 }
676
677 void ShenandoahBarrierSetAssembler::satb_barrier_c2(const MachNode* node, MacroAssembler* masm, Register addr, Register pre_val) {
678 assert_different_registers(addr, pre_val);
679 if (!ShenandoahSATBBarrierStubC2::needs_barrier(node)) {
680 return;
681 }
682 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
683 ShenandoahSATBBarrierStubC2* const stub = ShenandoahSATBBarrierStubC2::create(node, addr, pre_val);
684
685 // Check if GC marking is in progress, otherwise we don't have to do anything.
686 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
687 __ ldrb(rscratch1, gc_state);
688 __ tstw(rscratch1, ShenandoahHeap::MARKING);
689 __ br(Assembler::NE, *stub->entry());
690 __ bind(*stub->continuation());
691 }
692
693 void ShenandoahBarrierSetAssembler::card_barrier_c2(const MachNode* node, MacroAssembler* masm, Register addr, Register tmp) {
694 if (!ShenandoahCardBarrier ||
695 (node->barrier_data() & (ShenandoahBarrierCardMark | ShenandoahBarrierCardMarkNotNull)) == 0) {
696 return;
697 }
698
699 Assembler::InlineSkippedInstructionsCounter skip_counter(masm);
700 __ lsr(tmp, addr, CardTable::card_shift());
701
702 assert(CardTable::dirty_card_val() == 0, "must be");
703
704 Address curr_ct_holder_addr(rthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
705 __ ldr(rscratch1, curr_ct_holder_addr);
706
707 if (UseCondCardMark) {
708 Label L_already_dirty;
709 __ ldrb(rscratch2, Address(tmp, rscratch1));
710 __ cbz(rscratch2, L_already_dirty);
711 __ strb(zr, Address(tmp, rscratch1));
712 __ bind(L_already_dirty);
713 } else {
714 __ strb(zr, Address(tmp, rscratch1));
715 }
716 }
717
718 void ShenandoahBarrierSetAssembler::cmpxchg_oop_c2(const MachNode* node,
719 MacroAssembler* masm,
720 Register addr,
721 Register expected,
722 Register new_val,
723 Register result,
724 bool acquire, bool release, bool weak,
725 bool is_cae) {
726 Register tmp = rscratch2;
727 Assembler::operand_size size = UseCompressedOops ? Assembler::word : Assembler::xword;
728
729 assert_different_registers(addr, expected, result, tmp);
730 assert_different_registers(addr, new_val, result, tmp);
731
732 ShenandoahCASBarrierSlowStubC2* const slow_stub = ShenandoahCASBarrierSlowStubC2::create(node, addr, expected, new_val, result, tmp, is_cae, acquire, release, weak);
733 ShenandoahCASBarrierMidStubC2* const mid_stub = ShenandoahCASBarrierMidStubC2::create(node, slow_stub, expected, result, tmp, is_cae);
734
735 // Step 1. Fast-path.
736 //
737 // Try to CAS with given arguments. If successful, then we are done.
738 __ cmpxchg(addr, expected, new_val, size, acquire, release, weak, result);
739 // EQ flag set iff success. result holds value fetched.
740
741 __ br(Assembler::NE, *mid_stub->entry());
742
743 // Slow-stub re-enters with condition flags according to CAS, we may need to
744 // set result accordingly.
745 __ bind(*slow_stub->continuation());
746 if (!is_cae) {
747 __ cset(result, Assembler::EQ);
748 }
749
750 // Mid-stub re-enters with result set correctly.
751 __ bind(*mid_stub->continuation());
752 }
753
754 #undef __
755 #define __ masm.
756
757 void ShenandoahLoadRefBarrierStubC2::emit_code(MacroAssembler& masm) {
758 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
759 __ bind(*entry());
760 Register obj = _obj;
761 if (_narrow) {
762 __ decode_heap_oop(_tmp1, _obj);
763 obj = _tmp1;
764 }
765 // Weak/phantom loads always need to go to runtime.
766 if ((_node->barrier_data() & ShenandoahBarrierStrong) != 0) {
767 // Check for object in cset.
768 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr());
769 __ lsr(rscratch1, obj, ShenandoahHeapRegion::region_size_bytes_shift_jint());
770 __ ldrb(rscratch2, Address(rscratch2, rscratch1));
771 __ cbz(rscratch2, *continuation());
772 }
773 {
774 SaveLiveRegisters save_registers(&masm, this);
775 if (c_rarg0 != obj) {
776 if (c_rarg0 == _addr) {
777 __ mov(rscratch1, _addr);
778 _addr = rscratch1;
779 }
780 __ mov(c_rarg0, obj);
781 }
782 __ mov(c_rarg1, _addr);
783
784 if (_narrow) {
785 if ((_node->barrier_data() & ShenandoahBarrierStrong) != 0) {
786 __ mov(rscratch1, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow));
787 } else if ((_node->barrier_data() & ShenandoahBarrierWeak) != 0) {
788 __ mov(rscratch1, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow));
789 } else if ((_node->barrier_data() & ShenandoahBarrierPhantom) != 0) {
790 __ mov(rscratch1, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom_narrow));
791 }
792 } else {
793 if ((_node->barrier_data() & ShenandoahBarrierStrong) != 0) {
794 __ mov(rscratch1, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong));
795 } else if ((_node->barrier_data() & ShenandoahBarrierWeak) != 0) {
796 __ mov(rscratch1, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak));
797 } else if ((_node->barrier_data() & ShenandoahBarrierPhantom) != 0) {
798 __ mov(rscratch1, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom));
799 }
800 }
801 __ blr(rscratch1);
802 __ mov(_obj, r0);
803 }
804 if (_narrow) {
805 __ encode_heap_oop(_obj);
806 }
807 __ b(*continuation());
808 }
809
810 void ShenandoahSATBBarrierStubC2::emit_code(MacroAssembler& masm) {
811 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
812 __ bind(*entry());
813 // Do we need to load the previous value?
814 if (_addr != noreg) {
815 __ load_heap_oop(_preval, Address(_addr, 0), noreg, noreg, AS_RAW);
816 }
817 // Is the previous value null?
818 // __ cbz(_preval, *continuation());
819
820 Address index(rthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
821 Address buffer(rthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
822 Label runtime;
823 __ ldr(rscratch1, index);
824 // If buffer is full, call into runtime.
825 __ cbz(rscratch1, runtime);
826
827 // The buffer is not full, store value into it.
828 __ sub(rscratch1, rscratch1, wordSize);
829 __ str(rscratch1, index);
830 __ ldr(rscratch2, buffer);
831 __ str(_preval, Address(rscratch2, rscratch1));
832 __ b(*continuation());
833
834 // Runtime call
835 __ bind(runtime);
836 {
837 SaveLiveRegisters save_registers(&masm, this);
838 if (c_rarg0 != _preval) {
839 __ mov(c_rarg0, _preval);
840 }
841 __ mov(rscratch1, CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre_c2));
842 __ blr(rscratch1);
843 }
844 __ b(*continuation());
845 }
846
847 void ShenandoahCASBarrierMidStubC2::emit_code(MacroAssembler& masm) {
848 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
849 __ bind(*entry());
850
851 // Check if CAS result is null. If it is, then we must have a legitimate failure.
852 // This makes loading the fwdptr in the slow-path simpler.
853 __ tst(_result, _result);
854 // In case of !CAE, this has the correct value for legitimate failure (0/false)
855 // in result register.
856 __ br(Assembler::EQ, *continuation());
857
858 // Check if GC is in progress, otherwise we must have a legitimate failure.
859 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
860 __ ldrb(_tmp, gc_state);
861 __ tstw(_tmp, ShenandoahHeap::HAS_FORWARDED);
862 __ br(Assembler::NE, *_slow_stub->entry());
863
864 if (!_cae) {
865 __ mov(_result, 0); // result = false
866 }
867 __ b(*continuation());
868 }
869
870 void ShenandoahCASBarrierSlowStubC2::emit_code(MacroAssembler& masm) {
871 Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
872 __ bind(*entry());
873 Assembler::operand_size size = UseCompressedOops ? Assembler::word : Assembler::xword;
874
875 // Step 2. CAS has failed because the value held at addr does not
876 // match expected. This may be a false negative because the value fetched
877 // from addr (now held in result) may be a from-space pointer to the
878 // original copy of same object referenced by to-space pointer expected.
879 //
880 // To resolve this, it suffices to find the forward pointer associated
881 // with fetched value. If this matches expected, retry CAS with new
882 // parameters. If this mismatches, then we have a legitimate
883 // failure, and we're done.
884
885 // overwrite tmp with from-space pointer fetched from memory
886 __ mov(_tmp1, _result);
887
888 if (UseCompressedOops) {
889 // Decode tmp in order to resolve its forward pointer
890 __ decode_heap_oop_not_null(_tmp1, _tmp1);
891 }
892
893 // Load/decode forwarding pointer.
894 __ ldr(_tmp1, Address(_tmp1, oopDesc::mark_offset_in_bytes()));
895 // Negate the mark-word. This allows us to test lowest 2 bits easily while preserving the upper bits.
896 __ eon(_tmp1, _tmp1, zr);
897 __ ands(zr, _tmp1, markWord::lock_mask_in_place);
898 // Not forwarded, must have a legit CAS failure.
899 __ br(Assembler::NE, *continuation());
900 // Set the lowest two bits. This is equivalent to clearing the two bits after
901 // the subsequent inversion.
902 __ orr(_tmp1, _tmp1, markWord::marked_value);
903 // And invert back to get the forwardee.
904 __ eon(_tmp1, _tmp1, zr);
905
906 if (UseCompressedOops) {
907 // Encode tmp to compare against expected.
908 __ encode_heap_oop_not_null(_tmp1, _tmp1);
909 }
910
911 // Does forwarded value of fetched from-space pointer match original
912 // value of expected? If result holds null, this comparison will fail
913 // because we know from step1 that expected is not null. There is
914 // no need for a separate test for result (the value originally held
915 // in memory) equal to null.
916 __ cmp(_tmp1, _expected);
917
918 // If not, then the failure was legitimate and we're done.
919 // Branching to continuation with NE condition denotes failure.
920 __ br(Assembler::NE, *continuation());
921
922 // Fall through to step 3.
923
924 // Step 3. We've confirmed that the value originally held in memory
925 // (now held in result) pointed to from-space version of original
926 // expected value. Try the CAS again with the from-space expected
927 // value. If it now succeeds, we're good.
928 //
929 // Note: result holds encoded from-space pointer that matches to-space
930 // object residing at expected. result is the new "expected".
931
932 // Note that macro implementation of __cmpxchg cannot use same register
933 // tmp2 for result and expected since it overwrites result before it
934 // compares result with expected.
935 __ mov(_tmp1, _result);
936 __ cmpxchg(_addr_reg, _tmp1, _new_val, size, _acquire, _release, _weak, _result);
937 // EQ flag set iff success. result holds value fetched, rscratch1 clobbered.
938
939 // If fetched value did not equal the new expected, this could
940 // still be a false negative because some other thread may have
941 // newly overwritten the memory value with its to-space equivalent.
942 __ br(Assembler::EQ, *continuation());
943
944 // Step 4. Retry CAS with original to-space expected.
945 __ cmpxchg(_addr_reg, _expected, _new_val, size, _acquire, _release, _weak, _result);
946
947 __ b(*continuation());
948 }
949 #undef __
950 #define __ masm->
951 #endif // COMPILER2
952
953 void ShenandoahBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
954 Register start, Register count, Register scratch) {
955 assert(ShenandoahCardBarrier, "Should have been checked by caller");
956
957 Label L_loop, L_done;
958 const Register end = count;
959
960 // Zero count? Nothing to do.
961 __ cbz(count, L_done);
962
963 // end = start + count << LogBytesPerHeapOop
964 // last element address to make inclusive
965 __ lea(end, Address(start, count, Address::lsl(LogBytesPerHeapOop)));
966 __ sub(end, end, BytesPerHeapOop);
967 __ lsr(start, start, CardTable::card_shift());
968 __ lsr(end, end, CardTable::card_shift());
969
970 // number of bytes to copy
971 __ sub(count, end, start);
972
973 Address curr_ct_holder_addr(rthread, in_bytes(ShenandoahThreadLocalData::card_table_offset()));
974 __ ldr(scratch, curr_ct_holder_addr);
975 __ add(start, start, scratch);
976 __ bind(L_loop);
977 __ strb(zr, Address(start, count));
978 __ subs(count, count, 1);
979 __ br(Assembler::GE, L_loop);
980 __ bind(L_done);
981 }
982
983 #undef __
984
985 #ifdef COMPILER1
986
987 #define __ ce->masm()->
988
989 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) {
990 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
991 // At this point we know that marking is in progress.
992 // If do_load() is true then we have to emit the
993 // load of the previous value; otherwise it has already
994 // been loaded into _pre_val.
995
996 __ bind(*stub->entry());
997
998 assert(stub->pre_val()->is_register(), "Precondition.");
999
1000 Register pre_val_reg = stub->pre_val()->as_register();
1001
1002 if (stub->do_load()) {
1003 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/);
1004 }
1005 __ cbz(pre_val_reg, *stub->continuation());
1006 ce->store_parameter(stub->pre_val()->as_register(), 0);
1007 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
1008 __ b(*stub->continuation());
1009 }
1010
1011 void ShenandoahBarrierSetAssembler::gen_load_reference_barrier_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
1012 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
1013 __ bind(*stub->entry());
1014
1015 DecoratorSet decorators = stub->decorators();
1016 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
1017 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
1018 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
1019 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
1020
1021 Register obj = stub->obj()->as_register();
1022 Register res = stub->result()->as_register();
1023 Register addr = stub->addr()->as_pointer_register();
1024 Register tmp1 = stub->tmp1()->as_register();
1025 Register tmp2 = stub->tmp2()->as_register();
1026
1027 assert(res == r0, "result must arrive in r0");
1028
1029 if (res != obj) {
1030 __ mov(res, obj);
1031 }
1032
1033 if (is_strong) {
1034 // Check for object in cset.
1035 __ mov(tmp2, ShenandoahHeap::in_cset_fast_test_addr());
1036 __ lsr(tmp1, res, ShenandoahHeapRegion::region_size_bytes_shift_jint());
1037 __ ldrb(tmp2, Address(tmp2, tmp1));
1038 __ cbz(tmp2, *stub->continuation());
1039 }
1040
1041 ce->store_parameter(res, 0);
1042 ce->store_parameter(addr, 1);
1043 if (is_strong) {
1044 if (is_native) {
1045 __ far_call(RuntimeAddress(bs->load_reference_barrier_strong_native_rt_code_blob()->code_begin()));
1046 } else {
1047 __ far_call(RuntimeAddress(bs->load_reference_barrier_strong_rt_code_blob()->code_begin()));
1048 }
1049 } else if (is_weak) {
1050 __ far_call(RuntimeAddress(bs->load_reference_barrier_weak_rt_code_blob()->code_begin()));
1051 } else {
1052 assert(is_phantom, "only remaining strength");
1053 __ far_call(RuntimeAddress(bs->load_reference_barrier_phantom_rt_code_blob()->code_begin()));
1054 }
1055
1056 __ b(*stub->continuation());
1057 }
1058
1059 #undef __
1060
1061 #define __ sasm->
1062
1063 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
1064 __ prologue("shenandoah_pre_barrier", false);
1065
1066 // arg0 : previous value of memory
1067
1068 BarrierSet* bs = BarrierSet::barrier_set();
1069
1070 const Register pre_val = r0;
1071 const Register thread = rthread;
1072 const Register tmp = rscratch1;
1073
1074 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
1075 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
1076
1077 Label done;
1078 Label runtime;
1079
1080 // Is marking still active?
1081 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
1082 __ ldrb(tmp, gc_state);
1083 __ tbz(tmp, ShenandoahHeap::MARKING_BITPOS, done);
1084
1085 // Can we store original value in the thread's buffer?
1086 __ ldr(tmp, queue_index);
1087 __ cbz(tmp, runtime);
1088
1089 __ sub(tmp, tmp, wordSize);
1090 __ str(tmp, queue_index);
1091 __ ldr(rscratch2, buffer);
1092 __ add(tmp, tmp, rscratch2);
1093 __ load_parameter(0, rscratch2);
1094 __ str(rscratch2, Address(tmp, 0));
1095 __ b(done);
1096
1097 __ bind(runtime);
1098 __ push_call_clobbered_registers();
1099 __ load_parameter(0, pre_val);
1100 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre), pre_val);
1101 __ pop_call_clobbered_registers();
1102 __ bind(done);
1103
1104 __ epilogue();
1105 }
1106
1107 void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_stub(StubAssembler* sasm, DecoratorSet decorators) {
1108 __ prologue("shenandoah_load_reference_barrier", false);
1109 // arg0 : object to be resolved
1110
1111 __ push_call_clobbered_registers();
1112 __ load_parameter(0, r0);
1113 __ load_parameter(1, r1);
1114
1115 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
1116 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
1117 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
1118 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
1119 if (is_strong) {
1120 if (is_native) {
1121 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong));
1122 } else {
1123 if (UseCompressedOops) {
1124 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow));
1125 } else {
1126 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong));
1127 }
1128 }
1129 } else if (is_weak) {
1130 assert(!is_native, "weak must not be called off-heap");
1131 if (UseCompressedOops) {
1132 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow));
1133 } else {
1134 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak));
1135 }
1136 } else {
1137 assert(is_phantom, "only remaining strength");
1138 assert(is_native, "phantom must only be called off-heap");
1139 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom));
1140 }
1141 __ blr(lr);
1142 __ mov(rscratch1, r0);
1143 __ pop_call_clobbered_registers();
1144 __ mov(r0, rscratch1);
1145
1146 __ epilogue();
1147 }
1148
1149 #undef __
1150
1151 #endif // COMPILER1