1 /*
2 * Copyright (c) 2018, 2019, 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/shenandoahForwarding.hpp"
27 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
28 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
29 #include "gc/shenandoah/shenandoahHeuristics.hpp"
30 #include "gc/shenandoah/shenandoahRuntime.hpp"
31 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/interp_masm.hpp"
34 #include "runtime/sharedRuntime.hpp"
35 #include "runtime/thread.hpp"
36 #ifdef COMPILER1
37 #include "c1/c1_LIRAssembler.hpp"
38 #include "c1/c1_MacroAssembler.hpp"
39 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
40 #endif
41
42 #define __ masm->
43
44 address ShenandoahBarrierSetAssembler::_shenandoah_lrb = NULL;
45
46 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
47 Register src, Register dst, Register count, RegSet saved_regs) {
48 if (is_oop) {
49 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
50 if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) {
51
52 Label done;
53
54 // Avoid calling runtime if count == 0
55 __ cbz(count, done);
56
57 // Is marking active?
58 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
59 __ ldrb(rscratch1, gc_state);
60 if (dest_uninitialized) {
61 __ tbz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
62 } else {
63 __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING);
64 __ tst(rscratch1, rscratch2);
65 __ br(Assembler::EQ, done);
66 }
67
68 __ push(saved_regs, sp);
69 if (UseCompressedOops) {
70 if (dest_uninitialized) {
71 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_narrow_oop_entry), src, dst, count);
72 } else {
73 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_narrow_oop_entry), src, dst, count);
74 }
75 } else {
76 if (dest_uninitialized) {
77 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_oop_entry), src, dst, count);
78 } else {
79 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_oop_entry), src, dst, count);
80 }
81 }
82 __ pop(saved_regs, sp);
83 __ bind(done);
84 }
85 }
86 }
87
88 void ShenandoahBarrierSetAssembler::shenandoah_write_barrier_pre(MacroAssembler* masm,
89 Register obj,
90 Register pre_val,
91 Register thread,
92 Register tmp,
93 bool tosca_live,
94 bool expand_call) {
95 if (ShenandoahSATBBarrier) {
96 satb_write_barrier_pre(masm, obj, pre_val, thread, tmp, tosca_live, expand_call);
97 }
98 }
99
100 void ShenandoahBarrierSetAssembler::satb_write_barrier_pre(MacroAssembler* masm,
101 Register obj,
102 Register pre_val,
103 Register thread,
104 Register tmp,
105 bool tosca_live,
106 bool expand_call) {
107 // If expand_call is true then we expand the call_VM_leaf macro
108 // directly to skip generating the check by
109 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
110
111 assert(thread == rthread, "must be");
112
113 Label done;
114 Label runtime;
115
116 assert_different_registers(obj, pre_val, tmp, rscratch1);
117 assert(pre_val != noreg && tmp != noreg, "expecting a register");
118
119 Address in_progress(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset()));
120 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
121 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
122
123 // Is marking active?
124 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
125 __ ldrw(tmp, in_progress);
126 } else {
127 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
128 __ ldrb(tmp, in_progress);
129 }
130 __ cbzw(tmp, done);
131
132 // Do we need to load the previous value?
133 if (obj != noreg) {
134 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
135 }
136
137 // Is the previous value null?
138 __ cbz(pre_val, done);
139
140 // Can we store original value in the thread's buffer?
141 // Is index == 0?
142 // (The index field is typed as size_t.)
143
144 __ ldr(tmp, index); // tmp := *index_adr
145 __ cbz(tmp, runtime); // tmp == 0?
146 // If yes, goto runtime
147
148 __ sub(tmp, tmp, wordSize); // tmp := tmp - wordSize
149 __ str(tmp, index); // *index_adr := tmp
150 __ ldr(rscratch1, buffer);
151 __ add(tmp, tmp, rscratch1); // tmp := tmp + *buffer_adr
152
153 // Record the previous value
154 __ str(pre_val, Address(tmp, 0));
155 __ b(done);
156
157 __ bind(runtime);
158 // save the live input values
159 RegSet saved = RegSet::of(pre_val);
160 if (tosca_live) saved += RegSet::of(r0);
161 if (obj != noreg) saved += RegSet::of(obj);
162
163 __ push(saved, sp);
164
165 // Calling the runtime using the regular call_VM_leaf mechanism generates
166 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
167 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == NULL.
168 //
169 // If we care generating the pre-barrier without a frame (e.g. in the
170 // intrinsified Reference.get() routine) then ebp might be pointing to
171 // the caller frame and so this check will most likely fail at runtime.
172 //
173 // Expanding the call directly bypasses the generation of the check.
174 // So when we do not have have a full interpreter frame on the stack
175 // expand_call should be passed true.
176
177 if (expand_call) {
178 assert(pre_val != c_rarg1, "smashed arg");
179 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
180 } else {
181 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
182 }
183
184 __ pop(saved, sp);
185
186 __ bind(done);
187 }
188
189 void ShenandoahBarrierSetAssembler::resolve_forward_pointer(MacroAssembler* masm, Register dst, Register tmp) {
190 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
191 Label is_null;
192 __ cbz(dst, is_null);
193 resolve_forward_pointer_not_null(masm, dst, tmp);
194 __ bind(is_null);
195 }
196
197 // IMPORTANT: This must preserve all registers, even rscratch1 and rscratch2, except those explicitely
198 // passed in.
199 void ShenandoahBarrierSetAssembler::resolve_forward_pointer_not_null(MacroAssembler* masm, Register dst, Register tmp) {
200 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
201 // The below loads the mark word, checks if the lowest two bits are
202 // set, and if so, clear the lowest two bits and copy the result
203 // to dst. Otherwise it leaves dst alone.
204 // Implementing this is surprisingly awkward. I do it here by:
205 // - Inverting the mark word
206 // - Test lowest two bits == 0
207 // - If so, set the lowest two bits
208 // - Invert the result back, and copy to dst
209
210 bool borrow_reg = (tmp == noreg);
211 if (borrow_reg) {
212 // No free registers available. Make one useful.
213 tmp = rscratch1;
214 if (tmp == dst) {
215 tmp = rscratch2;
216 }
217 __ push(RegSet::of(tmp), sp);
218 }
219
220 assert_different_registers(tmp, dst);
221
222 Label done;
223 __ ldr(tmp, Address(dst, oopDesc::mark_offset_in_bytes()));
224 __ eon(tmp, tmp, zr);
225 __ ands(zr, tmp, markWord::lock_mask_in_place);
226 __ br(Assembler::NE, done);
227 __ orr(tmp, tmp, markWord::marked_value);
228 __ eon(dst, tmp, zr);
229 __ bind(done);
230
231 if (borrow_reg) {
232 __ pop(RegSet::of(tmp), sp);
233 }
234 }
235
236 void ShenandoahBarrierSetAssembler::load_reference_barrier_not_null(MacroAssembler* masm, Register dst, Address load_addr) {
237 assert(ShenandoahLoadRefBarrier, "Should be enabled");
238 assert(dst != rscratch2, "need rscratch2");
239 assert_different_registers(load_addr.base(), load_addr.index(), rscratch1, rscratch2);
240
241 Label done;
242 __ enter();
243 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
244 __ ldrb(rscratch2, gc_state);
245
246 // Check for heap stability
247 __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
248
249 // use r1 for load address
250 Register result_dst = dst;
251 if (dst == r1) {
252 __ mov(rscratch1, dst);
253 dst = rscratch1;
254 }
255
256 RegSet to_save_r1 = RegSet::of(r1);
257 // If outgoing register is r1, we can clobber it
258 if (result_dst != r1) {
259 __ push(to_save_r1, sp);
260 }
261 __ lea(r1, load_addr);
262
263 RegSet to_save_r0 = RegSet::of(r0);
264 if (dst != r0) {
265 __ push(to_save_r0, sp);
266 __ mov(r0, dst);
267 }
268
269 __ far_call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahBarrierSetAssembler::shenandoah_lrb())));
270
271 if (result_dst != r0) {
272 __ mov(result_dst, r0);
273 }
274
275 if (dst != r0) {
276 __ pop(to_save_r0, sp);
277 }
278
279 if (result_dst != r1) {
280 __ pop(to_save_r1, sp);
281 }
282
283 __ bind(done);
284 __ leave();
285 }
286
287 void ShenandoahBarrierSetAssembler::load_reference_barrier_native(MacroAssembler* masm, Register dst, Address load_addr) {
288 if (!ShenandoahLoadRefBarrier) {
289 return;
290 }
291
292 assert(dst != rscratch2, "need rscratch2");
293
294 Label is_null;
295 Label done;
296
297 __ block_comment("load_reference_barrier_native { ");
298
299 __ cbz(dst, is_null);
300
301 __ enter();
302
303 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
304 __ ldrb(rscratch2, gc_state);
305
306 // Check for heap in evacuation phase
307 __ tbz(rscratch2, ShenandoahHeap::EVACUATION_BITPOS, done);
308
309 __ mov(rscratch2, dst);
310 __ push_call_clobbered_registers();
311 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_native));
312 __ lea(r1, load_addr);
313 __ mov(r0, rscratch2);
314 __ blr(lr);
315 __ mov(rscratch2, r0);
316 __ pop_call_clobbered_registers();
317 __ mov(dst, rscratch2);
318
319 __ bind(done);
320 __ leave();
321 __ bind(is_null);
322 __ block_comment("} load_reference_barrier_native");
323 }
324
325 void ShenandoahBarrierSetAssembler::storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) {
326 if (ShenandoahStoreValEnqueueBarrier) {
327 // Save possibly live regs.
328 RegSet live_regs = RegSet::range(r0, r4) - dst;
329 __ push(live_regs, sp);
330 __ strd(v0, __ pre(sp, 2 * -wordSize));
331
332 satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false);
333
334 // Restore possibly live regs.
335 __ ldrd(v0, __ post(sp, 2 * wordSize));
336 __ pop(live_regs, sp);
337 }
338 }
339
340 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm, Register dst, Address load_addr) {
341 if (ShenandoahLoadRefBarrier) {
342 Label is_null;
343 __ cbz(dst, is_null);
344 load_reference_barrier_not_null(masm, dst, load_addr);
345 __ bind(is_null);
346 }
347 }
348
349 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
350 Register dst, Address src, Register tmp1, Register tmp_thread) {
351 bool on_oop = is_reference_type(type);
352 bool not_in_heap = (decorators & IN_NATIVE) != 0;
353 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
354 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
355 bool on_reference = on_weak || on_phantom;
356 bool is_traversal_mode = ShenandoahHeap::heap()->is_traversal_mode();
357 bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0 || is_traversal_mode;
358
359 Register result_dst = dst;
360
361 if (on_oop) {
362 // We want to preserve src
363 if (dst == src.base() || dst == src.index()) {
364 dst = rscratch1;
365 }
366 assert_different_registers(dst, src.base(), src.index());
367 }
368
369 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
370 if (on_oop) {
371 if (not_in_heap && !is_traversal_mode) {
372 load_reference_barrier_native(masm, dst, src);
373 } else {
374 load_reference_barrier(masm, dst, src);
375 }
376
377 if (dst != result_dst) {
378 __ mov(result_dst, dst);
379 dst = result_dst;
380 }
381
382 if (ShenandoahKeepAliveBarrier && on_reference && keep_alive) {
383 __ enter();
384 satb_write_barrier_pre(masm /* masm */,
385 noreg /* obj */,
386 dst /* pre_val */,
387 rthread /* thread */,
388 tmp1 /* tmp */,
389 true /* tosca_live */,
390 true /* expand_call */);
391 __ leave();
392 }
393 }
394 }
395
396 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
397 Address dst, Register val, Register tmp1, Register tmp2) {
398 bool on_oop = is_reference_type(type);
399 if (!on_oop) {
400 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2);
401 return;
402 }
403
404 // flatten object address if needed
405 if (dst.index() == noreg && dst.offset() == 0) {
406 if (dst.base() != r3) {
407 __ mov(r3, dst.base());
408 }
409 } else {
410 __ lea(r3, dst);
411 }
412
413 shenandoah_write_barrier_pre(masm,
414 r3 /* obj */,
415 tmp2 /* pre_val */,
416 rthread /* thread */,
417 tmp1 /* tmp */,
418 val != noreg /* tosca_live */,
419 false /* expand_call */);
420
421 if (val == noreg) {
422 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), noreg, noreg, noreg);
423 } else {
424 storeval_barrier(masm, val, tmp1);
425 // G1 barrier needs uncompressed oop for region cross check.
426 Register new_val = val;
427 if (UseCompressedOops) {
428 new_val = rscratch2;
429 __ mov(new_val, val);
430 }
431 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), val, noreg, noreg);
432 }
433
434 }
435
436 void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
437 Register obj, Register tmp, Label& slowpath) {
438 Label done;
439 // Resolve jobject
440 BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath);
441
442 // Check for null.
443 __ cbz(obj, done);
444
445 assert(obj != rscratch2, "need rscratch2");
446 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
447 __ ldrb(rscratch2, gc_state);
448
449 // Check for heap in evacuation phase
450 __ tbnz(rscratch2, ShenandoahHeap::EVACUATION_BITPOS, slowpath);
451
452 __ bind(done);
453 }
454
455
456 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val,
457 bool acquire, bool release, bool weak, bool is_cae,
458 Register result) {
459 Register tmp1 = rscratch1;
460 Register tmp2 = rscratch2;
461 bool is_narrow = UseCompressedOops;
462 Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword;
463
464 assert_different_registers(addr, expected, new_val, tmp1, tmp2);
465
466 Label retry, done, fail;
467
468 // CAS, using LL/SC pair.
469 __ bind(retry);
470 __ load_exclusive(tmp1, addr, size, acquire);
471 if (is_narrow) {
472 __ cmpw(tmp1, expected);
473 } else {
474 __ cmp(tmp1, expected);
475 }
476 __ br(Assembler::NE, fail);
477 __ store_exclusive(tmp2, new_val, addr, size, release);
478 if (weak) {
479 __ cmpw(tmp2, 0u); // If the store fails, return NE to our caller
480 } else {
481 __ cbnzw(tmp2, retry);
482 }
483 __ b(done);
484
485 __ bind(fail);
486 // Check if rb(expected)==rb(tmp1)
487 // Shuffle registers so that we have memory value ready for next expected.
488 __ mov(tmp2, expected);
489 __ mov(expected, tmp1);
490 if (is_narrow) {
491 __ decode_heap_oop(tmp1, tmp1);
492 __ decode_heap_oop(tmp2, tmp2);
493 }
494 resolve_forward_pointer(masm, tmp1);
495 resolve_forward_pointer(masm, tmp2);
496 __ cmp(tmp1, tmp2);
497 // Retry with expected now being the value we just loaded from addr.
498 __ br(Assembler::EQ, retry);
499 if (is_cae && is_narrow) {
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(tmp1, expected);
503 }
504 __ bind(done);
505
506 if (is_cae) {
507 __ mov(result, tmp1);
508 } else {
509 __ cset(result, Assembler::EQ);
510 }
511 }
512
513 #undef __
514
515 #ifdef COMPILER1
516
517 #define __ ce->masm()->
518
519 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) {
520 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
521 // At this point we know that marking is in progress.
522 // If do_load() is true then we have to emit the
523 // load of the previous value; otherwise it has already
524 // been loaded into _pre_val.
525
526 __ bind(*stub->entry());
527
528 assert(stub->pre_val()->is_register(), "Precondition.");
529
530 Register pre_val_reg = stub->pre_val()->as_register();
531
532 if (stub->do_load()) {
533 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/, false /*unaligned*/);
534 }
535 __ cbz(pre_val_reg, *stub->continuation());
536 ce->store_parameter(stub->pre_val()->as_register(), 0);
537 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
538 __ b(*stub->continuation());
539 }
540
541 void ShenandoahBarrierSetAssembler::gen_load_reference_barrier_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
542 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
543 __ bind(*stub->entry());
544
545 Register obj = stub->obj()->as_register();
546 Register res = stub->result()->as_register();
547 Register addr = stub->addr()->as_pointer_register();
548 Register tmp1 = stub->tmp1()->as_register();
549 Register tmp2 = stub->tmp2()->as_register();
550
551 assert(res == r0, "result must arrive in r0");
552
553 if (res != obj) {
554 __ mov(res, obj);
555 }
556
557 // Check for null.
558 __ cbz(res, *stub->continuation());
559
560 // Check for object in cset.
561 __ mov(tmp2, ShenandoahHeap::in_cset_fast_test_addr());
562 __ lsr(tmp1, res, ShenandoahHeapRegion::region_size_bytes_shift_jint());
563 __ ldrb(tmp2, Address(tmp2, tmp1));
564 __ cbz(tmp2, *stub->continuation());
565
566 // Check if object is already forwarded.
567 Label slow_path;
568 __ ldr(tmp1, Address(res, oopDesc::mark_offset_in_bytes()));
569 __ eon(tmp1, tmp1, zr);
570 __ ands(zr, tmp1, markWord::lock_mask_in_place);
571 __ br(Assembler::NE, slow_path);
572
573 // Decode forwarded object.
574 __ orr(tmp1, tmp1, markWord::marked_value);
575 __ eon(res, tmp1, zr);
576 __ b(*stub->continuation());
577
578 __ bind(slow_path);
579 ce->store_parameter(res, 0);
580 ce->store_parameter(addr, 1);
581 __ far_call(RuntimeAddress(bs->load_reference_barrier_rt_code_blob()->code_begin()));
582
583 __ b(*stub->continuation());
584 }
585
586 #undef __
587
588 #define __ sasm->
589
590 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
591 __ prologue("shenandoah_pre_barrier", false);
592
593 // arg0 : previous value of memory
594
595 BarrierSet* bs = BarrierSet::barrier_set();
596
597 const Register pre_val = r0;
598 const Register thread = rthread;
599 const Register tmp = rscratch1;
600
601 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
602 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
603
604 Label done;
605 Label runtime;
606
607 // Is marking still active?
608 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
609 __ ldrb(tmp, gc_state);
610 __ mov(rscratch2, ShenandoahHeap::MARKING | ShenandoahHeap::TRAVERSAL);
611 __ tst(tmp, rscratch2);
612 __ br(Assembler::EQ, done);
613
614 // Can we store original value in the thread's buffer?
615 __ ldr(tmp, queue_index);
616 __ cbz(tmp, runtime);
617
618 __ sub(tmp, tmp, wordSize);
619 __ str(tmp, queue_index);
620 __ ldr(rscratch2, buffer);
621 __ add(tmp, tmp, rscratch2);
622 __ load_parameter(0, rscratch2);
623 __ str(rscratch2, Address(tmp, 0));
624 __ b(done);
625
626 __ bind(runtime);
627 __ push_call_clobbered_registers();
628 __ load_parameter(0, pre_val);
629 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
630 __ pop_call_clobbered_registers();
631 __ bind(done);
632
633 __ epilogue();
634 }
635
636 void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_stub(StubAssembler* sasm) {
637 __ prologue("shenandoah_load_reference_barrier", false);
638 // arg0 : object to be resolved
639
640 __ push_call_clobbered_registers();
641 __ load_parameter(0, r0);
642 __ load_parameter(1, r1);
643 if (UseCompressedOops) {
644 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow));
645 } else {
646 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier));
647 }
648 __ blr(lr);
649 __ mov(rscratch1, r0);
650 __ pop_call_clobbered_registers();
651 __ mov(r0, rscratch1);
652
653 __ epilogue();
654 }
655
656 #undef __
657
658 #endif // COMPILER1
659
660 address ShenandoahBarrierSetAssembler::shenandoah_lrb() {
661 assert(_shenandoah_lrb != NULL, "need load reference barrier stub");
662 return _shenandoah_lrb;
663 }
664
665 #define __ cgen->assembler()->
666
667 // Shenandoah load reference barrier.
668 //
669 // Input:
670 // r0: OOP to evacuate. Not null.
671 // r1: load address
672 //
673 // Output:
674 // r0: Pointer to evacuated OOP.
675 //
676 // Trash rscratch1, rscratch2. Preserve everything else.
677 address ShenandoahBarrierSetAssembler::generate_shenandoah_lrb(StubCodeGenerator* cgen) {
678
679 __ align(6);
680 StubCodeMark mark(cgen, "StubRoutines", "shenandoah_lrb");
681 address start = __ pc();
682
683 Label work, done;
684 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr());
685 __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint());
686 __ ldrb(rscratch2, Address(rscratch2, rscratch1));
687 __ tbnz(rscratch2, 0, work);
688 __ ret(lr);
689 __ bind(work);
690
691 Label slow_path;
692 __ ldr(rscratch1, Address(r0, oopDesc::mark_offset_in_bytes()));
693 __ eon(rscratch1, rscratch1, zr);
694 __ ands(zr, rscratch1, markWord::lock_mask_in_place);
695 __ br(Assembler::NE, slow_path);
696
697 // Decode forwarded object.
698 __ orr(rscratch1, rscratch1, markWord::marked_value);
699 __ eon(r0, rscratch1, zr);
700 __ ret(lr);
701
702 __ bind(slow_path);
703 __ enter(); // required for proper stackwalking of RuntimeStub frame
704
705 __ push_call_clobbered_registers();
706
707 if (UseCompressedOops) {
708 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow));
709 } else {
710 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier));
711 }
712 __ blr(lr);
713 __ mov(rscratch1, r0);
714 __ pop_call_clobbered_registers();
715 __ mov(r0, rscratch1);
716
717 __ leave(); // required for proper stackwalking of RuntimeStub frame
718 __ bind(done);
719 __ ret(lr);
720
721 return start;
722 }
723
724 #undef __
725
726 void ShenandoahBarrierSetAssembler::barrier_stubs_init() {
727 if (ShenandoahLoadRefBarrier) {
728 int stub_code_size = 2048;
729 ResourceMark rm;
730 BufferBlob* bb = BufferBlob::create("shenandoah_barrier_stubs", stub_code_size);
731 CodeBuffer buf(bb);
732 StubCodeGenerator cgen(&buf);
733 _shenandoah_lrb = generate_shenandoah_lrb(&cgen);
734 }
735 }