1 /*
2 * Copyright (c) 2018, 2020, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
27 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
31 #include "gc/shenandoah/shenandoahHeuristics.hpp"
32 #include "gc/shenandoah/shenandoahRuntime.hpp"
33 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "interpreter/interp_masm.hpp"
36 #include "runtime/sharedRuntime.hpp"
37 #include "runtime/thread.hpp"
38 #ifdef COMPILER1
39 #include "c1/c1_LIRAssembler.hpp"
40 #include "c1/c1_MacroAssembler.hpp"
41 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
42 #endif
43
44 #define __ masm->
45
46 address ShenandoahBarrierSetAssembler::_shenandoah_lrb = NULL;
47
48 void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
49 Register src, Register dst, Register count, RegSet saved_regs) {
50 if (is_oop) {
51 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
52 if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) {
53
54 Label done;
55
56 // Avoid calling runtime if count == 0
57 __ cbz(count, done);
58
59 // Is marking active?
60 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
61 __ ldrb(rscratch1, gc_state);
62 if (dest_uninitialized) {
63 __ tbz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
64 } else {
65 __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING);
66 __ tst(rscratch1, rscratch2);
67 __ br(Assembler::EQ, done);
68 }
69
70 __ push(saved_regs, sp);
71 if (UseCompressedOops) {
72 if (dest_uninitialized) {
73 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_narrow_oop_entry), src, dst, count);
74 } else {
75 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_narrow_oop_entry), src, dst, count);
76 }
77 } else {
78 if (dest_uninitialized) {
79 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_oop_entry), src, dst, count);
80 } else {
81 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_oop_entry), src, dst, count);
82 }
83 }
84 __ pop(saved_regs, sp);
85 __ bind(done);
86 }
87 }
88 }
89
90 void ShenandoahBarrierSetAssembler::shenandoah_write_barrier_pre(MacroAssembler* masm,
91 Register obj,
92 Register pre_val,
93 Register thread,
94 Register tmp,
95 bool tosca_live,
96 bool expand_call) {
97 if (ShenandoahSATBBarrier) {
98 satb_write_barrier_pre(masm, obj, pre_val, thread, tmp, tosca_live, expand_call);
99 }
100 }
101
102 void ShenandoahBarrierSetAssembler::satb_write_barrier_pre(MacroAssembler* masm,
103 Register obj,
104 Register pre_val,
105 Register thread,
106 Register tmp,
107 bool tosca_live,
108 bool expand_call) {
109 // If expand_call is true then we expand the call_VM_leaf macro
110 // directly to skip generating the check by
111 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
112
113 assert(thread == rthread, "must be");
114
115 Label done;
116 Label runtime;
117
118 assert_different_registers(obj, pre_val, tmp, rscratch1);
119 assert(pre_val != noreg && tmp != noreg, "expecting a register");
120
121 Address in_progress(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset()));
122 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
123 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
124
125 // Is marking active?
126 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
127 __ ldrw(tmp, in_progress);
128 } else {
129 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
130 __ ldrb(tmp, in_progress);
131 }
132 __ cbzw(tmp, done);
133
134 // Do we need to load the previous value?
135 if (obj != noreg) {
136 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
137 }
138
139 // Is the previous value null?
140 __ cbz(pre_val, done);
141
142 // Can we store original value in the thread's buffer?
143 // Is index == 0?
144 // (The index field is typed as size_t.)
145
146 __ ldr(tmp, index); // tmp := *index_adr
147 __ cbz(tmp, runtime); // tmp == 0?
148 // If yes, goto runtime
149
150 __ sub(tmp, tmp, wordSize); // tmp := tmp - wordSize
151 __ str(tmp, index); // *index_adr := tmp
152 __ ldr(rscratch1, buffer);
153 __ add(tmp, tmp, rscratch1); // tmp := tmp + *buffer_adr
154
155 // Record the previous value
156 __ str(pre_val, Address(tmp, 0));
157 __ b(done);
158
159 __ bind(runtime);
160 // save the live input values
161 RegSet saved = RegSet::of(pre_val);
162 if (tosca_live) saved += RegSet::of(r0);
163 if (obj != noreg) saved += RegSet::of(obj);
164
165 __ push(saved, sp);
166
167 // Calling the runtime using the regular call_VM_leaf mechanism generates
168 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
169 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == NULL.
170 //
171 // If we care generating the pre-barrier without a frame (e.g. in the
172 // intrinsified Reference.get() routine) then ebp might be pointing to
173 // the caller frame and so this check will most likely fail at runtime.
174 //
175 // Expanding the call directly bypasses the generation of the check.
176 // So when we do not have have a full interpreter frame on the stack
177 // expand_call should be passed true.
178
179 if (expand_call) {
180 assert(pre_val != c_rarg1, "smashed arg");
181 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
182 } else {
183 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
184 }
185
186 __ pop(saved, sp);
187
188 __ bind(done);
189 }
190
191 void ShenandoahBarrierSetAssembler::resolve_forward_pointer(MacroAssembler* masm, Register dst, Register tmp) {
192 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
193 Label is_null;
194 __ cbz(dst, is_null);
195 resolve_forward_pointer_not_null(masm, dst, tmp);
196 __ bind(is_null);
197 }
198
199 // IMPORTANT: This must preserve all registers, even rscratch1 and rscratch2, except those explicitely
200 // passed in.
201 void ShenandoahBarrierSetAssembler::resolve_forward_pointer_not_null(MacroAssembler* masm, Register dst, Register tmp) {
202 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
203 // The below loads the mark word, checks if the lowest two bits are
204 // set, and if so, clear the lowest two bits and copy the result
205 // to dst. Otherwise it leaves dst alone.
206 // Implementing this is surprisingly awkward. I do it here by:
207 // - Inverting the mark word
208 // - Test lowest two bits == 0
209 // - If so, set the lowest two bits
210 // - Invert the result back, and copy to dst
211
212 bool borrow_reg = (tmp == noreg);
213 if (borrow_reg) {
214 // No free registers available. Make one useful.
215 tmp = rscratch1;
216 if (tmp == dst) {
217 tmp = rscratch2;
218 }
219 __ push(RegSet::of(tmp), sp);
220 }
221
222 assert_different_registers(tmp, dst);
223
224 Label done;
225 __ ldr(tmp, Address(dst, oopDesc::mark_offset_in_bytes()));
226 __ eon(tmp, tmp, zr);
227 __ ands(zr, tmp, markWord::lock_mask_in_place);
228 __ br(Assembler::NE, done);
229 __ orr(tmp, tmp, markWord::marked_value);
230 __ eon(dst, tmp, zr);
231 __ bind(done);
232
233 if (borrow_reg) {
234 __ pop(RegSet::of(tmp), sp);
235 }
236 }
237
238 void ShenandoahBarrierSetAssembler::load_reference_barrier_not_null(MacroAssembler* masm, Register dst, Address load_addr) {
239 assert(ShenandoahLoadRefBarrier, "Should be enabled");
240 assert(dst != rscratch2, "need rscratch2");
241 assert_different_registers(load_addr.base(), load_addr.index(), rscratch1, rscratch2);
242
243 Label done;
244 __ enter();
245 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
246 __ ldrb(rscratch2, gc_state);
247
248 // Check for heap stability
249 __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
250
251 // use r1 for load address
252 Register result_dst = dst;
253 if (dst == r1) {
254 __ mov(rscratch1, dst);
255 dst = rscratch1;
256 }
257
258 // Save r0 and r1, unless it is an output register
259 RegSet to_save = RegSet::of(r0, r1) - result_dst;
260 __ push(to_save, sp);
261 __ lea(r1, load_addr);
262 __ mov(r0, dst);
263
264 __ far_call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahBarrierSetAssembler::shenandoah_lrb())));
265
266 __ mov(result_dst, r0);
267 __ pop(to_save, sp);
268
269 __ bind(done);
270 __ leave();
271 }
272
273 void ShenandoahBarrierSetAssembler::load_reference_barrier_native(MacroAssembler* masm, Register dst, Address load_addr) {
274 if (!ShenandoahLoadRefBarrier) {
275 return;
276 }
277
278 assert(dst != rscratch2, "need rscratch2");
279
280 Label is_null;
281 Label done;
282
283 __ block_comment("load_reference_barrier_native { ");
284
285 __ cbz(dst, is_null);
286
287 __ enter();
288
289 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
290 __ ldrb(rscratch2, gc_state);
291
292 // Check for heap in evacuation phase
293 __ tbz(rscratch2, ShenandoahHeap::EVACUATION_BITPOS, done);
294
295 __ mov(rscratch2, dst);
296 __ push_call_clobbered_registers();
297 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_native));
298 __ lea(r1, load_addr);
299 __ mov(r0, rscratch2);
300 __ blr(lr);
301 __ mov(rscratch2, r0);
302 __ pop_call_clobbered_registers();
303 __ mov(dst, rscratch2);
304
305 __ bind(done);
306 __ leave();
307 __ bind(is_null);
308 __ block_comment("} load_reference_barrier_native");
309 }
310
311 void ShenandoahBarrierSetAssembler::storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) {
312 if (ShenandoahStoreValEnqueueBarrier) {
313 // Save possibly live regs.
314 RegSet live_regs = RegSet::range(r0, r4) - dst;
315 __ push(live_regs, sp);
316 __ strd(v0, __ pre(sp, 2 * -wordSize));
317
318 satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false);
319
320 // Restore possibly live regs.
321 __ ldrd(v0, __ post(sp, 2 * wordSize));
322 __ pop(live_regs, sp);
323 }
324 }
325
326 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm, Register dst, Address load_addr) {
327 if (ShenandoahLoadRefBarrier) {
328 Label is_null;
329 __ cbz(dst, is_null);
330 load_reference_barrier_not_null(masm, dst, load_addr);
331 __ bind(is_null);
332 }
333 }
334
335 //
336 // Arguments:
337 //
338 // Inputs:
339 // src: oop location to load from, might be clobbered
340 //
341 // Output:
342 // dst: oop loaded from src location
343 //
344 // Kill:
345 // rscratch1 (scratch reg)
346 //
347 // Alias:
348 // dst: rscratch1 (might use rscratch1 as temporary output register to avoid clobbering src)
349 //
350 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
351 Register dst, Address src, Register tmp1, Register tmp_thread) {
352 // 1: non-reference load, no additional barrier is needed
353 if (!is_reference_type(type)) {
354 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
355 return;
356 }
357
358 // 2: load a reference from src location and apply LRB if needed
359 if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) {
360 Register result_dst = dst;
361
362 // Preserve src location for LRB
363 if (dst == src.base() || dst == src.index()) {
364 dst = rscratch1;
365 }
366 assert_different_registers(dst, src.base(), src.index());
367
368 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
369
370 if (ShenandoahBarrierSet::use_load_reference_barrier_native(decorators, type)) {
371 load_reference_barrier_native(masm, dst, src);
372 } else {
373 load_reference_barrier(masm, dst, src);
374 }
375
376 if (dst != result_dst) {
377 __ mov(result_dst, dst);
378 dst = result_dst;
379 }
380 } else {
381 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
382 }
383
384 // 3: apply keep-alive barrier if needed
385 if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) {
386 __ enter();
387 __ push_call_clobbered_registers();
388 satb_write_barrier_pre(masm /* masm */,
389 noreg /* obj */,
390 dst /* pre_val */,
391 rthread /* thread */,
392 tmp1 /* tmp */,
393 true /* tosca_live */,
394 true /* expand_call */);
395 __ pop_call_clobbered_registers();
396 __ leave();
397 }
398 }
399
400 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
401 Address dst, Register val, Register tmp1, Register tmp2) {
402 bool on_oop = is_reference_type(type);
403 if (!on_oop) {
404 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2);
405 return;
406 }
407
408 // flatten object address if needed
409 if (dst.index() == noreg && dst.offset() == 0) {
410 if (dst.base() != r3) {
411 __ mov(r3, dst.base());
412 }
413 } else {
414 __ lea(r3, dst);
415 }
416
417 shenandoah_write_barrier_pre(masm,
418 r3 /* obj */,
419 tmp2 /* pre_val */,
420 rthread /* thread */,
421 tmp1 /* tmp */,
422 val != noreg /* tosca_live */,
423 false /* expand_call */);
424
425 if (val == noreg) {
426 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), noreg, noreg, noreg);
427 } else {
428 storeval_barrier(masm, val, tmp1);
429 // G1 barrier needs uncompressed oop for region cross check.
430 Register new_val = val;
431 if (UseCompressedOops) {
432 new_val = rscratch2;
433 __ mov(new_val, val);
434 }
435 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), val, noreg, noreg);
436 }
437
438 }
439
440 void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env,
441 Register obj, Register tmp, Label& slowpath) {
442 Label done;
443 // Resolve jobject
444 BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath);
445
446 // Check for null.
447 __ cbz(obj, done);
448
449 assert(obj != rscratch2, "need rscratch2");
450 Address gc_state(jni_env, ShenandoahThreadLocalData::gc_state_offset() - JavaThread::jni_environment_offset());
451 __ lea(rscratch2, gc_state);
452 __ ldrb(rscratch2, Address(rscratch2));
453
454 // Check for heap in evacuation phase
455 __ tbnz(rscratch2, ShenandoahHeap::EVACUATION_BITPOS, slowpath);
456
457 __ bind(done);
458 }
459
460
461 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val,
462 bool acquire, bool release, bool weak, bool is_cae,
463 Register result) {
464 Register tmp1 = rscratch1;
465 Register tmp2 = rscratch2;
466 bool is_narrow = UseCompressedOops;
467 Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword;
468
469 assert_different_registers(addr, expected, new_val, tmp1, tmp2);
470
471 Label retry, done, fail;
472
473 // CAS, using LL/SC pair.
474 __ bind(retry);
475 __ load_exclusive(tmp1, addr, size, acquire);
476 if (is_narrow) {
477 __ cmpw(tmp1, expected);
478 } else {
479 __ cmp(tmp1, expected);
480 }
481 __ br(Assembler::NE, fail);
482 __ store_exclusive(tmp2, new_val, addr, size, release);
483 if (weak) {
484 __ cmpw(tmp2, 0u); // If the store fails, return NE to our caller
485 } else {
486 __ cbnzw(tmp2, retry);
487 }
488 __ b(done);
489
490 __ bind(fail);
491 // Check if rb(expected)==rb(tmp1)
492 // Shuffle registers so that we have memory value ready for next expected.
493 __ mov(tmp2, expected);
494 __ mov(expected, tmp1);
495 if (is_narrow) {
496 __ decode_heap_oop(tmp1, tmp1);
497 __ decode_heap_oop(tmp2, tmp2);
498 }
499 resolve_forward_pointer(masm, tmp1);
500 resolve_forward_pointer(masm, tmp2);
501 __ cmp(tmp1, tmp2);
502 // Retry with expected now being the value we just loaded from addr.
503 __ br(Assembler::EQ, retry);
504 if (is_cae && is_narrow) {
505 // For cmp-and-exchange and narrow oops, we need to restore
506 // the compressed old-value. We moved it to 'expected' a few lines up.
507 __ mov(tmp1, expected);
508 }
509 __ bind(done);
510
511 if (is_cae) {
512 __ mov(result, tmp1);
513 } else {
514 __ cset(result, Assembler::EQ);
515 }
516 }
517
518 #undef __
519
520 #ifdef COMPILER1
521
522 #define __ ce->masm()->
523
524 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) {
525 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
526 // At this point we know that marking is in progress.
527 // If do_load() is true then we have to emit the
528 // load of the previous value; otherwise it has already
529 // been loaded into _pre_val.
530
531 __ bind(*stub->entry());
532
533 assert(stub->pre_val()->is_register(), "Precondition.");
534
535 Register pre_val_reg = stub->pre_val()->as_register();
536
537 if (stub->do_load()) {
538 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/, false /*unaligned*/);
539 }
540 __ cbz(pre_val_reg, *stub->continuation());
541 ce->store_parameter(stub->pre_val()->as_register(), 0);
542 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
543 __ b(*stub->continuation());
544 }
545
546 void ShenandoahBarrierSetAssembler::gen_load_reference_barrier_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
547 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
548 __ bind(*stub->entry());
549
550 Register obj = stub->obj()->as_register();
551 Register res = stub->result()->as_register();
552 Register addr = stub->addr()->as_pointer_register();
553 Register tmp1 = stub->tmp1()->as_register();
554 Register tmp2 = stub->tmp2()->as_register();
555
556 assert(res == r0, "result must arrive in r0");
557
558 if (res != obj) {
559 __ mov(res, obj);
560 }
561
562 // Check for null.
563 __ cbz(res, *stub->continuation());
564
565 // Check for object in cset.
566 __ mov(tmp2, ShenandoahHeap::in_cset_fast_test_addr());
567 __ lsr(tmp1, res, ShenandoahHeapRegion::region_size_bytes_shift_jint());
568 __ ldrb(tmp2, Address(tmp2, tmp1));
569 __ cbz(tmp2, *stub->continuation());
570
571 // Check if object is already forwarded.
572 Label slow_path;
573 __ ldr(tmp1, Address(res, oopDesc::mark_offset_in_bytes()));
574 __ eon(tmp1, tmp1, zr);
575 __ ands(zr, tmp1, markWord::lock_mask_in_place);
576 __ br(Assembler::NE, slow_path);
577
578 // Decode forwarded object.
579 __ orr(tmp1, tmp1, markWord::marked_value);
580 __ eon(res, tmp1, zr);
581 __ b(*stub->continuation());
582
583 __ bind(slow_path);
584 ce->store_parameter(res, 0);
585 ce->store_parameter(addr, 1);
586 if (stub->is_native()) {
587 __ far_call(RuntimeAddress(bs->load_reference_barrier_native_rt_code_blob()->code_begin()));
588 } else {
589 __ far_call(RuntimeAddress(bs->load_reference_barrier_rt_code_blob()->code_begin()));
590 }
591
592 __ b(*stub->continuation());
593 }
594
595 #undef __
596
597 #define __ sasm->
598
599 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
600 __ prologue("shenandoah_pre_barrier", false);
601
602 // arg0 : previous value of memory
603
604 BarrierSet* bs = BarrierSet::barrier_set();
605
606 const Register pre_val = r0;
607 const Register thread = rthread;
608 const Register tmp = rscratch1;
609
610 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
611 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
612
613 Label done;
614 Label runtime;
615
616 // Is marking still active?
617 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
618 __ ldrb(tmp, gc_state);
619 __ mov(rscratch2, ShenandoahHeap::MARKING | ShenandoahHeap::TRAVERSAL);
620 __ tst(tmp, rscratch2);
621 __ br(Assembler::EQ, done);
622
623 // Can we store original value in the thread's buffer?
624 __ ldr(tmp, queue_index);
625 __ cbz(tmp, runtime);
626
627 __ sub(tmp, tmp, wordSize);
628 __ str(tmp, queue_index);
629 __ ldr(rscratch2, buffer);
630 __ add(tmp, tmp, rscratch2);
631 __ load_parameter(0, rscratch2);
632 __ str(rscratch2, Address(tmp, 0));
633 __ b(done);
634
635 __ bind(runtime);
636 __ push_call_clobbered_registers();
637 __ load_parameter(0, pre_val);
638 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
639 __ pop_call_clobbered_registers();
640 __ bind(done);
641
642 __ epilogue();
643 }
644
645 void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_stub(StubAssembler* sasm, bool is_native) {
646 __ prologue("shenandoah_load_reference_barrier", false);
647 // arg0 : object to be resolved
648
649 __ push_call_clobbered_registers();
650 __ load_parameter(0, r0);
651 __ load_parameter(1, r1);
652 if (is_native) {
653 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_native));
654 } else if (UseCompressedOops) {
655 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow));
656 } else {
657 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier));
658 }
659 __ blr(lr);
660 __ mov(rscratch1, r0);
661 __ pop_call_clobbered_registers();
662 __ mov(r0, rscratch1);
663
664 __ epilogue();
665 }
666
667 #undef __
668
669 #endif // COMPILER1
670
671 address ShenandoahBarrierSetAssembler::shenandoah_lrb() {
672 assert(_shenandoah_lrb != NULL, "need load reference barrier stub");
673 return _shenandoah_lrb;
674 }
675
676 #define __ cgen->assembler()->
677
678 // Shenandoah load reference barrier.
679 //
680 // Input:
681 // r0: OOP to evacuate. Not null.
682 // r1: load address
683 //
684 // Output:
685 // r0: Pointer to evacuated OOP.
686 //
687 // Trash rscratch1, rscratch2. Preserve everything else.
688 address ShenandoahBarrierSetAssembler::generate_shenandoah_lrb(StubCodeGenerator* cgen) {
689
690 __ align(6);
691 StubCodeMark mark(cgen, "StubRoutines", "shenandoah_lrb");
692 address start = __ pc();
693
694 Label work, done;
695 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr());
696 __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint());
697 __ ldrb(rscratch2, Address(rscratch2, rscratch1));
698 __ tbnz(rscratch2, 0, work);
699 __ ret(lr);
700 __ bind(work);
701
702 Label slow_path;
703 __ ldr(rscratch1, Address(r0, oopDesc::mark_offset_in_bytes()));
704 __ eon(rscratch1, rscratch1, zr);
705 __ ands(zr, rscratch1, markWord::lock_mask_in_place);
706 __ br(Assembler::NE, slow_path);
707
708 // Decode forwarded object.
709 __ orr(rscratch1, rscratch1, markWord::marked_value);
710 __ eon(r0, rscratch1, zr);
711 __ ret(lr);
712
713 __ bind(slow_path);
714 __ enter(); // required for proper stackwalking of RuntimeStub frame
715
716 __ push_call_clobbered_registers();
717
718 if (UseCompressedOops) {
719 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow));
720 } else {
721 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier));
722 }
723 __ blr(lr);
724 __ mov(rscratch1, r0);
725 __ pop_call_clobbered_registers();
726 __ mov(r0, rscratch1);
727
728 __ leave(); // required for proper stackwalking of RuntimeStub frame
729 __ bind(done);
730 __ ret(lr);
731
732 return start;
733 }
734
735 #undef __
736
737 void ShenandoahBarrierSetAssembler::barrier_stubs_init() {
738 if (ShenandoahLoadRefBarrier) {
739 int stub_code_size = 2048;
740 ResourceMark rm;
741 BufferBlob* bb = BufferBlob::create("shenandoah_barrier_stubs", stub_code_size);
742 CodeBuffer buf(bb);
743 StubCodeGenerator cgen(&buf);
744 _shenandoah_lrb = generate_shenandoah_lrb(&cgen);
745 }
746 }