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.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 && !ShenandoahHeap::heap()->heuristics()->can_do_traversal_gc()) {
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 __ tbz(rscratch1, ShenandoahHeap::MARKING_BITPOS, done);
61
62 __ push(saved_regs, sp);
63 if (count == c_rarg0) {
64 if (dst == c_rarg1) {
65 // exactly backwards!!
66 __ mov(rscratch1, c_rarg0);
67 __ mov(c_rarg0, c_rarg1);
68 __ mov(c_rarg1, rscratch1);
69 } else {
70 __ mov(c_rarg1, count);
71 __ mov(c_rarg0, dst);
72 }
73 } else {
74 __ mov(c_rarg0, dst);
75 __ mov(c_rarg1, count);
76 }
77 if (UseCompressedOops) {
78 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_narrow_oop_entry), 2);
79 } else {
80 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_oop_entry), 2);
81 }
82 __ pop(saved_regs, sp);
83 __ bind(done);
84 }
85 }
86 }
87
88 void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop,
89 Register start, Register count, Register scratch, RegSet saved_regs) {
90 if (is_oop) {
91 Label done;
92
93 // Avoid calling runtime if count == 0
94 __ cbz(count, done);
95
96 // Is updating references?
97 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
98 __ ldrb(rscratch1, gc_state);
99 __ tbz(rscratch1, ShenandoahHeap::UPDATEREFS_BITPOS, done);
100
101 __ push(saved_regs, sp);
102 assert_different_registers(start, count, scratch);
103 assert_different_registers(c_rarg0, count);
104 __ mov(c_rarg0, start);
105 __ mov(c_rarg1, count);
106 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_post_entry), 2);
107 __ pop(saved_regs, sp);
108
109 __ bind(done);
110 }
111 }
112
113 void ShenandoahBarrierSetAssembler::shenandoah_write_barrier_pre(MacroAssembler* masm,
114 Register obj,
115 Register pre_val,
116 Register thread,
117 Register tmp,
118 bool tosca_live,
119 bool expand_call) {
120 if (ShenandoahSATBBarrier) {
121 satb_write_barrier_pre(masm, obj, pre_val, thread, tmp, tosca_live, expand_call);
122 }
123 }
124
125 void ShenandoahBarrierSetAssembler::satb_write_barrier_pre(MacroAssembler* masm,
126 Register obj,
127 Register pre_val,
128 Register thread,
129 Register tmp,
130 bool tosca_live,
131 bool expand_call) {
132 // If expand_call is true then we expand the call_VM_leaf macro
133 // directly to skip generating the check by
134 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
135
136 assert(thread == rthread, "must be");
137
138 Label done;
139 Label runtime;
140
141 assert_different_registers(obj, pre_val, tmp, rscratch1);
142 assert(pre_val != noreg && tmp != noreg, "expecting a register");
143
144 Address in_progress(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset()));
145 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
146 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
147
148 // Is marking active?
149 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
150 __ ldrw(tmp, in_progress);
151 } else {
152 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
153 __ ldrb(tmp, in_progress);
154 }
155 __ cbzw(tmp, done);
156
157 // Do we need to load the previous value?
158 if (obj != noreg) {
159 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW);
160 }
161
162 // Is the previous value null?
163 __ cbz(pre_val, done);
164
165 // Can we store original value in the thread's buffer?
166 // Is index == 0?
167 // (The index field is typed as size_t.)
168
169 __ ldr(tmp, index); // tmp := *index_adr
170 __ cbz(tmp, runtime); // tmp == 0?
171 // If yes, goto runtime
172
173 __ sub(tmp, tmp, wordSize); // tmp := tmp - wordSize
174 __ str(tmp, index); // *index_adr := tmp
175 __ ldr(rscratch1, buffer);
176 __ add(tmp, tmp, rscratch1); // tmp := tmp + *buffer_adr
177
178 // Record the previous value
179 __ str(pre_val, Address(tmp, 0));
180 __ b(done);
181
182 __ bind(runtime);
183 // save the live input values
184 RegSet saved = RegSet::of(pre_val);
185 if (tosca_live) saved += RegSet::of(r0);
186 if (obj != noreg) saved += RegSet::of(obj);
187
188 __ push(saved, sp);
189
190 // Calling the runtime using the regular call_VM_leaf mechanism generates
191 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
192 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == NULL.
193 //
194 // If we care generating the pre-barrier without a frame (e.g. in the
195 // intrinsified Reference.get() routine) then ebp might be pointing to
196 // the caller frame and so this check will most likely fail at runtime.
197 //
198 // Expanding the call directly bypasses the generation of the check.
199 // So when we do not have have a full interpreter frame on the stack
200 // expand_call should be passed true.
201
202 if (expand_call) {
203 assert(pre_val != c_rarg1, "smashed arg");
204 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
205 } else {
206 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
207 }
208
209 __ pop(saved, sp);
210
211 __ bind(done);
212 }
213
214 void ShenandoahBarrierSetAssembler::resolve_forward_pointer(MacroAssembler* masm, Register dst, Register tmp) {
215 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
216 Label is_null;
217 __ cbz(dst, is_null);
218 resolve_forward_pointer_not_null(masm, dst, tmp);
219 __ bind(is_null);
220 }
221
222 // IMPORTANT: This must preserve all registers, even rscratch1 and rscratch2, except those explicitely
223 // passed in.
224 void ShenandoahBarrierSetAssembler::resolve_forward_pointer_not_null(MacroAssembler* masm, Register dst, Register tmp) {
225 assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled");
226 // The below loads the mark word, checks if the lowest two bits are
227 // set, and if so, clear the lowest two bits and copy the result
228 // to dst. Otherwise it leaves dst alone.
229 // Implementing this is surprisingly awkward. I do it here by:
230 // - Inverting the mark word
231 // - Test lowest two bits == 0
232 // - If so, set the lowest two bits
233 // - Invert the result back, and copy to dst
234
235 bool borrow_reg = (tmp == noreg);
236 if (borrow_reg) {
237 // No free registers available. Make one useful.
238 tmp = rscratch1;
239 __ push(RegSet::of(tmp), sp);
240 }
241
242 Label done;
243 __ ldr(tmp, Address(dst, oopDesc::mark_offset_in_bytes()));
244 __ eon(tmp, tmp, zr);
245 __ ands(zr, tmp, markOopDesc::lock_mask_in_place);
246 __ br(Assembler::NE, done);
247 __ orr(tmp, tmp, markOopDesc::marked_value);
248 __ eon(dst, tmp, zr);
249 __ bind(done);
250
251 if (borrow_reg) {
252 __ pop(RegSet::of(tmp), sp);
253 }
254 }
255
256 void ShenandoahBarrierSetAssembler::load_reference_barrier_not_null(MacroAssembler* masm, Register dst, Register tmp) {
257 assert(ShenandoahLoadRefBarrier, "Should be enabled");
258 assert(dst != rscratch2, "need rscratch2");
259
260 Label done;
261 __ enter();
262 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
263 __ ldrb(rscratch2, gc_state);
264
265 // Check for heap stability
266 __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
267
268 RegSet to_save = RegSet::of(r0);
269 if (dst != r0) {
270 __ push(to_save, sp);
271 __ mov(r0, dst);
272 }
273
274 __ far_call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahBarrierSetAssembler::shenandoah_lrb())));
275
276 if (dst != r0) {
277 __ mov(dst, r0);
278 __ pop(to_save, sp);
279 }
280
281 __ bind(done);
282 __ leave();
283 }
284
285 void ShenandoahBarrierSetAssembler::storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) {
286 if (ShenandoahStoreValEnqueueBarrier) {
287 // Save possibly live regs.
288 RegSet live_regs = RegSet::range(r0, r4) - dst;
289 __ push(live_regs, sp);
290 __ strd(v0, __ pre(sp, 2 * -wordSize));
291
292 satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false);
293
294 // Restore possibly live regs.
295 __ ldrd(v0, __ post(sp, 2 * wordSize));
296 __ pop(live_regs, sp);
297 }
298 }
299
300 void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm, Register dst, Register tmp) {
301 if (ShenandoahLoadRefBarrier) {
302 Label is_null;
303 __ cbz(dst, is_null);
304 load_reference_barrier_not_null(masm, dst, tmp);
305 __ bind(is_null);
306 }
307 }
308
309 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
310 Register dst, Address src, Register tmp1, Register tmp_thread) {
311 bool on_oop = type == T_OBJECT || type == T_ARRAY;
312 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
313 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
314 bool on_reference = on_weak || on_phantom;
315
316 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread);
317 if (on_oop) {
318 load_reference_barrier(masm, dst, tmp1);
319
320 if (ShenandoahKeepAliveBarrier && on_reference) {
321 __ enter();
322 satb_write_barrier_pre(masm /* masm */,
323 noreg /* obj */,
324 dst /* pre_val */,
325 rthread /* thread */,
326 tmp1 /* tmp */,
327 true /* tosca_live */,
328 true /* expand_call */);
329 __ leave();
330 }
331 }
332 }
333
334 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
335 Address dst, Register val, Register tmp1, Register tmp2) {
336 bool on_oop = type == T_OBJECT || type == T_ARRAY;
337 if (!on_oop) {
338 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2);
339 return;
340 }
341
342 // flatten object address if needed
343 if (dst.index() == noreg && dst.offset() == 0) {
344 if (dst.base() != r3) {
345 __ mov(r3, dst.base());
346 }
347 } else {
348 __ lea(r3, dst);
349 }
350
351 shenandoah_write_barrier_pre(masm,
352 r3 /* obj */,
353 tmp2 /* pre_val */,
354 rthread /* thread */,
355 tmp1 /* tmp */,
356 val != noreg /* tosca_live */,
357 false /* expand_call */);
358
359 if (val == noreg) {
360 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), noreg, noreg, noreg);
361 } else {
362 storeval_barrier(masm, val, tmp1);
363 // G1 barrier needs uncompressed oop for region cross check.
364 Register new_val = val;
365 if (UseCompressedOops) {
366 new_val = rscratch2;
367 __ mov(new_val, val);
368 }
369 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), val, noreg, noreg);
370 }
371
372 }
373
374 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val,
375 bool acquire, bool release, bool weak, bool is_cae,
376 Register result) {
377 Register tmp1 = rscratch1;
378 Register tmp2 = rscratch2;
379 bool is_narrow = UseCompressedOops;
380 Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword;
381
382 assert_different_registers(addr, expected, new_val, tmp1, tmp2);
383
384 Label retry, done, fail;
385
386 // CAS, using LL/SC pair.
387 __ bind(retry);
388 __ load_exclusive(tmp1, addr, size, acquire);
389 if (is_narrow) {
390 __ cmpw(tmp1, expected);
391 } else {
392 __ cmp(tmp1, expected);
393 }
394 __ br(Assembler::NE, fail);
395 __ store_exclusive(tmp2, new_val, addr, size, release);
396 if (weak) {
397 __ cmpw(tmp2, 0u); // If the store fails, return NE to our caller
398 } else {
399 __ cbnzw(tmp2, retry);
400 }
401 __ b(done);
402
403 __ bind(fail);
404 // Check if rb(expected)==rb(tmp1)
405 // Shuffle registers so that we have memory value ready for next expected.
406 __ mov(tmp2, expected);
407 __ mov(expected, tmp1);
408 if (is_narrow) {
409 __ decode_heap_oop(tmp1, tmp1);
410 __ decode_heap_oop(tmp2, tmp2);
411 }
412 resolve_forward_pointer(masm, tmp1);
413 resolve_forward_pointer(masm, tmp2);
414 __ cmp(tmp1, tmp2);
415 // Retry with expected now being the value we just loaded from addr.
416 __ br(Assembler::EQ, retry);
417 if (is_cae && is_narrow) {
418 // For cmp-and-exchange and narrow oops, we need to restore
419 // the compressed old-value. We moved it to 'expected' a few lines up.
420 __ mov(tmp1, expected);
421 }
422 __ bind(done);
423
424 if (is_cae) {
425 __ mov(result, tmp1);
426 } else {
427 __ cset(result, Assembler::EQ);
428 }
429 }
430
431 #undef __
432
433 #ifdef COMPILER1
434
435 #define __ ce->masm()->
436
437 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) {
438 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
439 // At this point we know that marking is in progress.
440 // If do_load() is true then we have to emit the
441 // load of the previous value; otherwise it has already
442 // been loaded into _pre_val.
443
444 __ bind(*stub->entry());
445
446 assert(stub->pre_val()->is_register(), "Precondition.");
447
448 Register pre_val_reg = stub->pre_val()->as_register();
449
450 if (stub->do_load()) {
451 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/, false /*unaligned*/);
452 }
453 __ cbz(pre_val_reg, *stub->continuation());
454 ce->store_parameter(stub->pre_val()->as_register(), 0);
455 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin()));
456 __ b(*stub->continuation());
457 }
458
459 void ShenandoahBarrierSetAssembler::gen_load_reference_barrier_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) {
460
461 Register obj = stub->obj()->as_register();
462 Register res = stub->result()->as_register();
463
464 Label done;
465
466 __ bind(*stub->entry());
467
468 if (res != obj) {
469 __ mov(res, obj);
470 }
471 // Check for null.
472 if (stub->needs_null_check()) {
473 __ cbz(res, done);
474 }
475
476 load_reference_barrier_not_null(ce->masm(), res, rscratch1);
477
478 __ bind(done);
479 __ b(*stub->continuation());
480 }
481
482 #undef __
483
484 #define __ sasm->
485
486 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) {
487 __ prologue("shenandoah_pre_barrier", false);
488
489 // arg0 : previous value of memory
490
491 BarrierSet* bs = BarrierSet::barrier_set();
492
493 const Register pre_val = r0;
494 const Register thread = rthread;
495 const Register tmp = rscratch1;
496
497 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
498 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
499
500 Label done;
501 Label runtime;
502
503 // Is marking still active?
504 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
505 __ ldrb(tmp, gc_state);
506 __ mov(rscratch2, ShenandoahHeap::MARKING | ShenandoahHeap::TRAVERSAL);
507 __ tst(tmp, rscratch2);
508 __ br(Assembler::EQ, done);
509
510 // Can we store original value in the thread's buffer?
511 __ ldr(tmp, queue_index);
512 __ cbz(tmp, runtime);
513
514 __ sub(tmp, tmp, wordSize);
515 __ str(tmp, queue_index);
516 __ ldr(rscratch2, buffer);
517 __ add(tmp, tmp, rscratch2);
518 __ load_parameter(0, rscratch2);
519 __ str(rscratch2, Address(tmp, 0));
520 __ b(done);
521
522 __ bind(runtime);
523 __ push_call_clobbered_registers();
524 __ load_parameter(0, pre_val);
525 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread);
526 __ pop_call_clobbered_registers();
527 __ bind(done);
528
529 __ epilogue();
530 }
531
532 #undef __
533
534 #endif // COMPILER1
535
536 address ShenandoahBarrierSetAssembler::shenandoah_lrb() {
537 assert(_shenandoah_lrb != NULL, "need load reference barrier stub");
538 return _shenandoah_lrb;
539 }
540
541 #define __ cgen->assembler()->
542
543 // Shenandoah load reference barrier.
544 //
545 // Input:
546 // r0: OOP to evacuate. Not null.
547 //
548 // Output:
549 // r0: Pointer to evacuated OOP.
550 //
551 // Trash rscratch1, rscratch2. Preserve everything else.
552 address ShenandoahBarrierSetAssembler::generate_shenandoah_lrb(StubCodeGenerator* cgen) {
553
554 __ align(6);
555 StubCodeMark mark(cgen, "StubRoutines", "shenandoah_lrb");
556 address start = __ pc();
557
558 Label work, done;
559 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr());
560 __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint());
561 __ ldrb(rscratch2, Address(rscratch2, rscratch1));
562 __ tbnz(rscratch2, 0, work);
563 __ ret(lr);
564 __ bind(work);
565
566 __ mov(rscratch2, r0);
567 resolve_forward_pointer_not_null(cgen->assembler(), r0, rscratch1);
568 __ cmp(rscratch2, r0);
569 __ br(Assembler::NE, done);
570
571 __ enter(); // required for proper stackwalking of RuntimeStub frame
572
573 __ push_call_clobbered_registers();
574
575 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_JRT));
576 __ blrt(lr, 1, 0, MacroAssembler::ret_type_integral);
577 __ mov(rscratch1, r0);
578 __ pop_call_clobbered_registers();
579 __ mov(r0, rscratch1);
580
581 __ leave(); // required for proper stackwalking of RuntimeStub frame
582 __ bind(done);
583 __ ret(lr);
584
585 return start;
586 }
587
588 #undef __
589
590 void ShenandoahBarrierSetAssembler::barrier_stubs_init() {
591 if (ShenandoahLoadRefBarrier) {
592 int stub_code_size = 2048;
593 ResourceMark rm;
594 BufferBlob* bb = BufferBlob::create("shenandoah_barrier_stubs", stub_code_size);
595 CodeBuffer buf(bb);
596 StubCodeGenerator cgen(&buf);
597 _shenandoah_lrb = generate_shenandoah_lrb(&cgen);
598 }
599 }