1 /*
2 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
26 #include "gc/shenandoah/shenandoahHeap.hpp"
27 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
28 #include "gc/shenandoah/shenandoahHeuristics.hpp"
29 #include "gc/shenandoah/shenandoahRuntime.hpp"
30 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
31 #include "interpreter/interpreter.hpp"
32 #include "interpreter/interp_masm.hpp"
33 #include "runtime/sharedRuntime.hpp"
34 #include "runtime/thread.hpp"
35 #ifdef COMPILER1
36 #include "c1/c1_LIRAssembler.hpp"
37 #include "c1/c1_MacroAssembler.hpp"
38 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
39 #endif
40
41 #define __ masm->
42
43 address ShenandoahBarrierSetAssembler::_shenandoah_wb = NULL;
44
45 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
46 Register addr, Register count, RegSet saved_regs) {
47 if (is_oop) {
48 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
49 if (!dest_uninitialized && !ShenandoahHeap::heap()->heuristics()->can_do_traversal_gc()) {
50 __ push(saved_regs, sp);
51 if (count == c_rarg0) {
52 if (addr == c_rarg1) {
53 // exactly backwards!!
54 __ mov(rscratch1, c_rarg0);
55 __ mov(c_rarg0, c_rarg1);
56 __ mov(c_rarg1, rscratch1);
57 } else {
58 __ mov(c_rarg1, count);
59 __ mov(c_rarg0, addr);
60 }
61 } else {
62 __ mov(c_rarg0, addr);
63 __ mov(c_rarg1, count);
64 }
65 if (UseCompressedOops) {
66 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_narrow_oop_entry), 2);
67 } else {
68 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_oop_entry), 2);
69 }
70 __ pop(saved_regs, sp);
71 }
72 }
73 }
74
75 void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
76 Register start, Register end, Register scratch, RegSet saved_regs) {
77 if (is_oop) {
78 __ push(saved_regs, sp);
79 // must compute element count unless barrier set interface is changed (other platforms supply count)
80 assert_different_registers(start, end, scratch);
81 __ lea(scratch, Address(end, BytesPerHeapOop));
82 __ sub(scratch, scratch, start); // subtract start to get #bytes
83 __ lsr(scratch, scratch, LogBytesPerHeapOop); // convert to element count
84 __ mov(c_rarg0, start);
85 __ mov(c_rarg1, scratch);
86 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_post_entry), 2);
87 __ pop(saved_regs, sp);
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, 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 tmp,
108 bool tosca_live,
109 bool expand_call) {
110 // If expand_call is true then we expand the call_VM_leaf macro
111 // directly to skip generating the check by
112 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
113
114 assert(thread == rthread, "must be");
115
116 Label done;
117 Label runtime;
118
119 assert_different_registers(obj, pre_val, tmp, rscratch1);
120 assert(pre_val != noreg && tmp != noreg, "expecting a register");
121
122 Address in_progress(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset()));
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 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
128 __ ldrw(tmp, in_progress);
129 } else {
130 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
131 __ ldrb(tmp, in_progress);
132 }
133 __ cbzw(tmp, done);
134
135 // Do we need to load the previous value?
136 if (obj != noreg) {
137 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
138 }
139
140 // Is the previous value null?
141 __ cbz(pre_val, done);
142
143 // Can we store original value in the thread's buffer?
144 // Is index == 0?
145 // (The index field is typed as size_t.)
146
147 __ ldr(tmp, index); // tmp := *index_adr
148 __ cbz(tmp, runtime); // tmp == 0?
149 // If yes, goto runtime
150
151 __ sub(tmp, tmp, wordSize); // tmp := tmp - wordSize
152 __ str(tmp, index); // *index_adr := tmp
153 __ ldr(rscratch1, buffer);
154 __ add(tmp, tmp, rscratch1); // tmp := tmp + *buffer_adr
155
156 // Record the previous value
157 __ str(pre_val, Address(tmp, 0));
158 __ b(done);
159
160 __ bind(runtime);
161 // save the live input values
162 RegSet saved = RegSet::of(pre_val);
163 if (tosca_live) saved += RegSet::of(r0);
164 if (obj != noreg) saved += RegSet::of(obj);
165
166 __ push(saved, sp);
167
168 // Calling the runtime using the regular call_VM_leaf mechanism generates
169 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
170 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == NULL.
171 //
172 // If we care generating the pre-barrier without a frame (e.g. in the
173 // intrinsified Reference.get() routine) then ebp might be pointing to
174 // the caller frame and so this check will most likely fail at runtime.
175 //
176 // Expanding the call directly bypasses the generation of the check.
177 // So when we do not have have a full interpreter frame on the stack
178 // expand_call should be passed true.
179
180 if (expand_call) {
181 assert(pre_val != c_rarg1, "smashed arg");
182 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
183 } else {
184 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
185 }
186
187 __ pop(saved, sp);
188
189 __ bind(done);
190 }
191
192 void ShenandoahBarrierSetAssembler::read_barrier(MacroAssembler* masm, Register dst) {
193 if (ShenandoahReadBarrier) {
194 read_barrier_impl(masm, dst);
195 }
196 }
197
198 void ShenandoahBarrierSetAssembler::read_barrier_impl(MacroAssembler* masm, Register dst) {
199 assert(UseShenandoahGC && (ShenandoahReadBarrier || ShenandoahStoreValReadBarrier || ShenandoahCASBarrier), "should be enabled");
200 Label is_null;
201 __ cbz(dst, is_null);
202 read_barrier_not_null_impl(masm, dst);
203 __ bind(is_null);
204 }
205
206 void ShenandoahBarrierSetAssembler::read_barrier_not_null(MacroAssembler* masm, Register dst) {
207 if (ShenandoahReadBarrier) {
208 read_barrier_not_null_impl(masm, dst);
209 }
210 }
211
212
213 void ShenandoahBarrierSetAssembler::read_barrier_not_null_impl(MacroAssembler* masm, Register dst) {
214 assert(UseShenandoahGC && (ShenandoahReadBarrier || ShenandoahStoreValReadBarrier || ShenandoahCASBarrier), "should be enabled");
215 __ ldr(dst, Address(dst, ShenandoahBrooksPointer::byte_offset()));
216 }
217
218 void ShenandoahBarrierSetAssembler::write_barrier(MacroAssembler* masm, Register dst) {
219 if (ShenandoahWriteBarrier) {
220 write_barrier_impl(masm, dst);
221 }
222 }
223
224 void ShenandoahBarrierSetAssembler::write_barrier_impl(MacroAssembler* masm, Register dst) {
225 assert(UseShenandoahGC && (ShenandoahWriteBarrier || ShenandoahStoreValEnqueueBarrier), "Should be enabled");
226 assert(dst != rscratch1, "need rscratch1");
227 assert(dst != rscratch2, "need rscratch2");
228
229 Label done;
230
231 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
232 __ ldrb(rscratch1, gc_state);
233
234 // Check for heap stability
235 __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL);
236 __ tst(rscratch1, rscratch2);
237 __ br(Assembler::EQ, done);
238
239 // Heap is unstable, need to perform the read-barrier even if WB is inactive
240 __ ldr(dst, Address(dst, ShenandoahBrooksPointer::byte_offset()));
241
242 // Check for evacuation-in-progress and jump to WB slow-path if needed
243 __ mov(rscratch2, ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL);
244 __ tst(rscratch1, rscratch2);
245 __ br(Assembler::EQ, done);
246
247 RegSet to_save = RegSet::of(r0);
248 if (dst != r0) {
249 __ push(to_save, sp);
250 __ mov(r0, dst);
251 }
252
253 __ far_call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahBarrierSetAssembler::shenandoah_wb())));
254
255 if (dst != r0) {
256 __ mov(dst, r0);
257 __ pop(to_save, sp);
258 }
259
260 __ bind(done);
261 }
262
263 void ShenandoahBarrierSetAssembler::storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) {
264 if (ShenandoahStoreValEnqueueBarrier) {
265 Label is_null;
266 __ cbz(dst, is_null);
267 write_barrier_impl(masm, dst);
268 __ bind(is_null);
269 // Save possibly live regs.
270 RegSet live_regs = RegSet::range(r0, r4) - dst;
271 __ push(live_regs, sp);
272 __ strd(v0, __ pre(sp, 2 * -wordSize));
273
274 satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false);
275
276 // Restore possibly live regs.
277 __ ldrd(v0, __ post(sp, 2 * wordSize));
278 __ pop(live_regs, sp);
279 }
280 if (ShenandoahStoreValReadBarrier) {
281 read_barrier_impl(masm, dst);
282 }
283 }
284
285 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
286 Register dst, Address src, Register tmp1, Register tmp_thread) {
287 bool on_oop = type == T_OBJECT || type == T_ARRAY;
288 bool in_heap = (decorators & IN_HEAP) != 0;
289 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
290 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
291 bool on_reference = on_weak || on_phantom;
292
293 if (in_heap) {
294 read_barrier_not_null(masm, src.base());
295 }
296
297 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
298 if (ShenandoahKeepAliveBarrier && on_oop && on_reference) {
299 __ enter();
300 satb_write_barrier_pre(masm /* masm */,
301 noreg /* obj */,
302 dst /* pre_val */,
303 rthread /* thread */,
304 tmp1 /* tmp */,
305 true /* tosca_live */,
306 true /* expand_call */);
307 __ leave();
308 }
309 }
310
311 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
312 Address dst, Register val, Register tmp1, Register tmp2) {
313 bool on_oop = type == T_OBJECT || type == T_ARRAY;
314 bool in_heap = (decorators & IN_HEAP) != 0;
315 if (in_heap) {
316 write_barrier(masm, dst.base());
317 }
318 if (!on_oop) {
319 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2);
320 return;
321 }
322
323 // flatten object address if needed
324 if (dst.index() == noreg && dst.offset() == 0) {
325 if (dst.base() != r3) {
326 __ mov(r3, dst.base());
327 }
328 } else {
329 __ lea(r3, dst);
330 }
331
332 shenandoah_write_barrier_pre(masm,
333 r3 /* obj */,
334 tmp2 /* pre_val */,
335 rthread /* thread */,
336 tmp1 /* tmp */,
337 val != noreg /* tosca_live */,
338 false /* expand_call */);
339
340 if (val == noreg) {
341 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), noreg, noreg, noreg);
342 } else {
343 storeval_barrier(masm, val, tmp1);
344 // G1 barrier needs uncompressed oop for region cross check.
345 Register new_val = val;
346 if (UseCompressedOops) {
347 new_val = rscratch2;
348 __ mov(new_val, val);
349 }
350 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), val, noreg, noreg);
351 }
352
353 }
354
355 void ShenandoahBarrierSetAssembler::obj_equals(MacroAssembler* masm, Register op1, Register op2) {
356 __ cmp(op1, op2);
357 if (ShenandoahAcmpBarrier) {
358 Label done;
359 __ br(Assembler::EQ, done);
360 // The object may have been evacuated, but we won't see it without a
361 // membar here.
362 __ membar(Assembler::LoadStore| Assembler::LoadLoad);
363 read_barrier(masm, op1);
364 read_barrier(masm, op2);
365 __ cmp(op1, op2);
366 __ bind(done);
367 }
368 }
369
370 void ShenandoahBarrierSetAssembler::tlab_allocate(MacroAssembler* masm, Register obj,
371 Register var_size_in_bytes,
372 int con_size_in_bytes,
373 Register t1,
374 Register t2,
375 Label& slow_case) {
376
377 assert_different_registers(obj, t2);
378 assert_different_registers(obj, var_size_in_bytes);
379 Register end = t2;
380
381 __ ldr(obj, Address(rthread, JavaThread::tlab_top_offset()));
382 if (var_size_in_bytes == noreg) {
383 __ lea(end, Address(obj, (int) (con_size_in_bytes + ShenandoahBrooksPointer::byte_size())));
384 } else {
385 __ add(var_size_in_bytes, var_size_in_bytes, ShenandoahBrooksPointer::byte_size());
386 __ lea(end, Address(obj, var_size_in_bytes));
387 }
388 __ ldr(rscratch1, Address(rthread, JavaThread::tlab_end_offset()));
389 __ cmp(end, rscratch1);
390 __ br(Assembler::HI, slow_case);
391
392 // update the tlab top pointer
393 __ str(end, Address(rthread, JavaThread::tlab_top_offset()));
394
395 __ add(obj, obj, ShenandoahBrooksPointer::byte_size());
396 __ str(obj, Address(obj, ShenandoahBrooksPointer::byte_offset()));
397
398 // recover var_size_in_bytes if necessary
399 if (var_size_in_bytes == end) {
400 __ sub(var_size_in_bytes, var_size_in_bytes, obj);
401 }
402 }
403
404 void ShenandoahBarrierSetAssembler::resolve(MacroAssembler* masm, DecoratorSet decorators, Register obj) {
405 bool oop_not_null = (decorators & IS_NOT_NULL) != 0;
406 bool is_write = (decorators & ACCESS_WRITE) != 0;
407 if (is_write) {
408 if (oop_not_null) {
409 write_barrier(masm, obj);
410 } else {
411 Label done;
412 __ cbz(obj, done);
413 write_barrier(masm, obj);
414 __ bind(done);
415 }
416 } else {
417 if (oop_not_null) {
418 read_barrier_not_null(masm, obj);
419 } else {
420 read_barrier(masm, obj);
421 }
422 }
423 }
424
425 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val,
426 bool acquire, bool release, bool weak, bool encode,
427 Register tmp1, Register tmp2, Register tmp3,
428 Register result) {
429
430 if (!ShenandoahCASBarrier) {
431 if (UseCompressedOops) {
432 if (encode) {
433 __ encode_heap_oop(tmp1, expected);
434 expected = tmp1;
435 __ encode_heap_oop(tmp3, new_val);
436 new_val = tmp3;
437 }
438 __ cmpxchg(addr, expected, new_val, Assembler::word, /* acquire*/ true, /* release*/ true, /* weak*/ false, rscratch1);
439 __ membar(__ AnyAny);
440 } else {
441 __ cmpxchg(addr, expected, new_val, Assembler::xword, /* acquire*/ true, /* release*/ true, /* weak*/ false, rscratch1);
442 __ membar(__ AnyAny);
443 }
444 return;
445 }
446
447 if (encode) {
448 storeval_barrier(masm, new_val, tmp3);
449 }
450
451 if (UseCompressedOops) {
452 if (encode) {
453 __ encode_heap_oop(tmp1, expected);
454 expected = tmp1;
455 __ encode_heap_oop(tmp2, new_val);
456 new_val = tmp2;
457 }
458 }
459 bool is_cae = (result != noreg);
460 bool is_narrow = UseCompressedOops;
461 Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword;
462 if (! is_cae) result = rscratch1;
463
464 assert_different_registers(addr, expected, new_val, result, tmp3);
465
466 Label retry, done, fail;
467
468 // CAS, using LL/SC pair.
469 __ bind(retry);
470 __ load_exclusive(result, addr, size, acquire);
471 if (is_narrow) {
472 __ cmpw(result, expected);
473 } else {
474 __ cmp(result, expected);
475 }
476 __ br(Assembler::NE, fail);
477 __ store_exclusive(tmp3, new_val, addr, size, release);
478 if (weak) {
479 __ cmpw(tmp3, 0u); // If the store fails, return NE to our caller
480 } else {
481 __ cbnzw(tmp3, retry);
482 }
483 __ b(done);
484
485 __ bind(fail);
486 // Check if rb(expected)==rb(result)
487 // Shuffle registers so that we have memory value ready for next expected.
488 __ mov(tmp3, expected);
489 __ mov(expected, result);
490 if (is_narrow) {
491 __ decode_heap_oop(result, result);
492 __ decode_heap_oop(tmp3, tmp3);
493 }
494 read_barrier_impl(masm, result);
495 read_barrier_impl(masm, tmp3);
496 __ cmp(result, tmp3);
497 // Retry with expected now being the value we just loaded from addr.
498 __ br(Assembler::EQ, retry);
499 if (is_narrow && is_cae) {
500 // For cmp-and-exchange and narrow oops, we need to restore
501 // the compressed old-value. We moved it to 'expected' a few lines up.
502 __ mov(result, expected);
503 }
504 __ bind(done);
505
506 }
507
508 #ifdef COMPILER1
509
510 #undef __
511 #define __ ce->masm()->
512
513 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) {
514 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
515 // At this point we know that marking is in progress.
516 // If do_load() is true then we have to emit the
517 // load of the previous value; otherwise it has already
518 // been loaded into _pre_val.
519
520 __ bind(*stub->entry());
521
522 assert(stub->pre_val()->is_register(), "Precondition.");
523
524 Register pre_val_reg = stub->pre_val()->as_register();
525
526 if (stub->do_load()) {
527 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/, false /*unaligned*/);
528 }
529 __ cbz(pre_val_reg, *stub->continuation());
530 ce->store_parameter(stub->pre_val()->as_register(), 0);
531 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
532 __ b(*stub->continuation());
533 }
534
535 void ShenandoahBarrierSetAssembler::gen_write_barrier_stub(LIR_Assembler* ce, ShenandoahWriteBarrierStub* stub) {
536
537 Register obj = stub->obj()->as_register();
538 Register res = stub->result()->as_register();
539
540 Label done;
541
542 __ bind(*stub->entry());
543
544 if (res != obj) {
545 __ mov(res, obj);
546 }
547 // Check for null.
548 if (stub->needs_null_check()) {
549 __ cbz(res, done);
550 }
551
552 write_barrier(ce->masm(), res);
553
554 __ bind(done);
555 __ b(*stub->continuation());
556 }
557
558 #undef __
559
560 #define __ sasm->
561
562 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
563 __ prologue("shenandoah_pre_barrier", false);
564
565 // arg0 : previous value of memory
566
567 BarrierSet* bs = BarrierSet::barrier_set();
568
569 const Register pre_val = r0;
570 const Register thread = rthread;
571 const Register tmp = rscratch1;
572
573 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
574 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
575
576 Label done;
577 Label runtime;
578
579 // Is marking still active?
580 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
581 __ ldrb(tmp, gc_state);
582 __ mov(rscratch2, ShenandoahHeap::MARKING | ShenandoahHeap::TRAVERSAL);
583 __ tst(tmp, rscratch2);
584 __ br(Assembler::EQ, done);
585
586 // Can we store original value in the thread's buffer?
587 __ ldr(tmp, queue_index);
588 __ cbz(tmp, runtime);
589
590 __ sub(tmp, tmp, wordSize);
591 __ str(tmp, queue_index);
592 __ ldr(rscratch2, buffer);
593 __ add(tmp, tmp, rscratch2);
594 __ load_parameter(0, rscratch2);
595 __ str(rscratch2, Address(tmp, 0));
596 __ b(done);
597
598 __ bind(runtime);
599 __ push_call_clobbered_registers();
600 __ load_parameter(0, pre_val);
601 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
602 __ pop_call_clobbered_registers();
603 __ bind(done);
604
605 __ epilogue();
606 }
607
608 #undef __
609
610 #endif // COMPILER1
611
612 address ShenandoahBarrierSetAssembler::shenandoah_wb() {
613 assert(_shenandoah_wb != NULL, "need write barrier stub");
614 return _shenandoah_wb;
615 }
616
617 #define __ cgen->assembler()->
618
619 // Shenandoah write barrier.
620 //
621 // Input:
622 // r0: OOP to evacuate. Not null.
623 //
624 // Output:
625 // r0: Pointer to evacuated OOP.
626 //
627 // Trash rscratch1, rscratch2. Preserve everything else.
628 address ShenandoahBarrierSetAssembler::generate_shenandoah_wb(StubCodeGenerator* cgen) {
629
630 __ align(6);
631 StubCodeMark mark(cgen, "StubRoutines", "shenandoah_wb");
632 address start = __ pc();
633
634 Label work;
635 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr());
636 __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint());
637 __ ldrb(rscratch2, Address(rscratch2, rscratch1));
638 __ tbnz(rscratch2, 0, work);
639 __ ret(lr);
640 __ bind(work);
641
642 Register obj = r0;
643
644 __ enter(); // required for proper stackwalking of RuntimeStub frame
645
646 __ push_call_clobbered_registers();
647
648 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_JRT));
649 __ blrt(lr, 1, 0, MacroAssembler::ret_type_integral);
650 __ mov(rscratch1, obj);
651 __ pop_call_clobbered_registers();
652 __ mov(obj, rscratch1);
653
654 __ leave(); // required for proper stackwalking of RuntimeStub frame
655 __ ret(lr);
656
657 return start;
658 }
659
660 #undef __
661
662 void ShenandoahBarrierSetAssembler::barrier_stubs_init() {
663 if (ShenandoahWriteBarrier || ShenandoahStoreValEnqueueBarrier) {
664 int stub_code_size = 2048;
665 ResourceMark rm;
666 BufferBlob* bb = BufferBlob::create("shenandoah_barrier_stubs", stub_code_size);
667 CodeBuffer buf(bb);
668 StubCodeGenerator cgen(&buf);
669 _shenandoah_wb = generate_shenandoah_wb(&cgen);
670 }
671 }