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 (ShenandoahSATBBarrier && !dest_uninitialized && !ShenandoahHeap::heap()->heuristics()->can_do_traversal_gc()) { 50 51 Label done; 52 53 // Avoid calling runtime if count == 0 54 __ cbz(count, done); 55 56 // Is marking active? 57 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset())); 58 __ ldrb(rscratch1, gc_state); 59 __ tbz(rscratch1, ShenandoahHeap::MARKING_BITPOS, done); 60 61 __ push(saved_regs, sp); 62 if (count == c_rarg0) { 63 if (addr == c_rarg1) { 64 // exactly backwards!! 65 __ mov(rscratch1, c_rarg0); 66 __ mov(c_rarg0, c_rarg1); 67 __ mov(c_rarg1, rscratch1); 68 } else { 69 __ mov(c_rarg1, count); 70 __ mov(c_rarg0, addr); 71 } 72 } else { 73 __ mov(c_rarg0, addr); 74 __ mov(c_rarg1, count); 75 } 76 if (UseCompressedOops) { 77 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_narrow_oop_entry), 2); 78 } else { 79 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_oop_entry), 2); 80 } 81 __ pop(saved_regs, sp); 82 __ bind(done); 83 } 84 } 85 } 86 87 void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop, 88 Register start, Register count, Register scratch, RegSet saved_regs) { 89 if (is_oop) { 90 __ push(saved_regs, sp); 91 assert_different_registers(start, count, scratch); 92 assert_different_registers(c_rarg0, count); 93 __ mov(c_rarg0, start); 94 __ mov(c_rarg1, count); 95 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_post_entry), 2); 96 __ pop(saved_regs, sp); 97 } 98 } 99 100 void ShenandoahBarrierSetAssembler::shenandoah_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 (ShenandoahSATBBarrier) { 108 satb_write_barrier_pre(masm, obj, pre_val, thread, tmp, tosca_live, expand_call); 109 } 110 } 111 112 void ShenandoahBarrierSetAssembler::satb_write_barrier_pre(MacroAssembler* masm, 113 Register obj, 114 Register pre_val, 115 Register thread, 116 Register tmp, 117 bool tosca_live, 118 bool expand_call) { 119 // If expand_call is true then we expand the call_VM_leaf macro 120 // directly to skip generating the check by 121 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp. 122 123 assert(thread == rthread, "must be"); 124 125 Label done; 126 Label runtime; 127 128 assert_different_registers(obj, pre_val, tmp, rscratch1); 129 assert(pre_val != noreg && tmp != noreg, "expecting a register"); 130 131 Address in_progress(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset())); 132 Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset())); 133 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset())); 134 135 // Is marking active? 136 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) { 137 __ ldrw(tmp, in_progress); 138 } else { 139 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption"); 140 __ ldrb(tmp, in_progress); 141 } 142 __ cbzw(tmp, done); 143 144 // Do we need to load the previous value? 145 if (obj != noreg) { 146 __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW); 147 } 148 149 // Is the previous value null? 150 __ cbz(pre_val, done); 151 152 // Can we store original value in the thread's buffer? 153 // Is index == 0? 154 // (The index field is typed as size_t.) 155 156 __ ldr(tmp, index); // tmp := *index_adr 157 __ cbz(tmp, runtime); // tmp == 0? 158 // If yes, goto runtime 159 160 __ sub(tmp, tmp, wordSize); // tmp := tmp - wordSize 161 __ str(tmp, index); // *index_adr := tmp 162 __ ldr(rscratch1, buffer); 163 __ add(tmp, tmp, rscratch1); // tmp := tmp + *buffer_adr 164 165 // Record the previous value 166 __ str(pre_val, Address(tmp, 0)); 167 __ b(done); 168 169 __ bind(runtime); 170 // save the live input values 171 RegSet saved = RegSet::of(pre_val); 172 if (tosca_live) saved += RegSet::of(r0); 173 if (obj != noreg) saved += RegSet::of(obj); 174 175 __ push(saved, sp); 176 177 // Calling the runtime using the regular call_VM_leaf mechanism generates 178 // code (generated by InterpreterMacroAssember::call_VM_leaf_base) 179 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == NULL. 180 // 181 // If we care generating the pre-barrier without a frame (e.g. in the 182 // intrinsified Reference.get() routine) then ebp might be pointing to 183 // the caller frame and so this check will most likely fail at runtime. 184 // 185 // Expanding the call directly bypasses the generation of the check. 186 // So when we do not have have a full interpreter frame on the stack 187 // expand_call should be passed true. 188 189 if (expand_call) { 190 assert(pre_val != c_rarg1, "smashed arg"); 191 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread); 192 } else { 193 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread); 194 } 195 196 __ pop(saved, sp); 197 198 __ bind(done); 199 } 200 201 void ShenandoahBarrierSetAssembler::read_barrier(MacroAssembler* masm, Register dst) { 202 if (ShenandoahReadBarrier) { 203 read_barrier_impl(masm, dst); 204 } 205 } 206 207 void ShenandoahBarrierSetAssembler::read_barrier_impl(MacroAssembler* masm, Register dst) { 208 assert(UseShenandoahGC && (ShenandoahReadBarrier || ShenandoahStoreValReadBarrier || ShenandoahCASBarrier), "should be enabled"); 209 Label is_null; 210 __ cbz(dst, is_null); 211 read_barrier_not_null_impl(masm, dst); 212 __ bind(is_null); 213 } 214 215 void ShenandoahBarrierSetAssembler::read_barrier_not_null(MacroAssembler* masm, Register dst) { 216 if (ShenandoahReadBarrier) { 217 read_barrier_not_null_impl(masm, dst); 218 } 219 } 220 221 222 void ShenandoahBarrierSetAssembler::read_barrier_not_null_impl(MacroAssembler* masm, Register dst) { 223 assert(UseShenandoahGC && (ShenandoahReadBarrier || ShenandoahStoreValReadBarrier || ShenandoahCASBarrier), "should be enabled"); 224 __ ldr(dst, Address(dst, ShenandoahBrooksPointer::byte_offset())); 225 } 226 227 void ShenandoahBarrierSetAssembler::write_barrier(MacroAssembler* masm, Register dst) { 228 if (ShenandoahWriteBarrier) { 229 write_barrier_impl(masm, dst); 230 } 231 } 232 233 void ShenandoahBarrierSetAssembler::write_barrier_impl(MacroAssembler* masm, Register dst) { 234 assert(UseShenandoahGC && (ShenandoahWriteBarrier || ShenandoahStoreValEnqueueBarrier), "Should be enabled"); 235 assert(dst != rscratch1, "need rscratch1"); 236 assert(dst != rscratch2, "need rscratch2"); 237 238 Label done; 239 240 Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset())); 241 __ ldrb(rscratch1, gc_state); 242 243 // Check for heap stability 244 __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL); 245 __ tst(rscratch1, rscratch2); 246 __ br(Assembler::EQ, done); 247 248 // Heap is unstable, need to perform the read-barrier even if WB is inactive 249 __ ldr(dst, Address(dst, ShenandoahBrooksPointer::byte_offset())); 250 251 // Check for evacuation-in-progress and jump to WB slow-path if needed 252 __ mov(rscratch2, ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL); 253 __ tst(rscratch1, rscratch2); 254 __ br(Assembler::EQ, done); 255 256 RegSet to_save = RegSet::of(r0); 257 if (dst != r0) { 258 __ push(to_save, sp); 259 __ mov(r0, dst); 260 } 261 262 __ far_call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahBarrierSetAssembler::shenandoah_wb()))); 263 264 if (dst != r0) { 265 __ mov(dst, r0); 266 __ pop(to_save, sp); 267 } 268 269 __ bind(done); 270 } 271 272 void ShenandoahBarrierSetAssembler::storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) { 273 if (ShenandoahStoreValEnqueueBarrier) { 274 Label is_null; 275 __ cbz(dst, is_null); 276 write_barrier_impl(masm, dst); 277 __ bind(is_null); 278 // Save possibly live regs. 279 RegSet live_regs = RegSet::range(r0, r4) - dst; 280 __ push(live_regs, sp); 281 __ strd(v0, __ pre(sp, 2 * -wordSize)); 282 283 satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false); 284 285 // Restore possibly live regs. 286 __ ldrd(v0, __ post(sp, 2 * wordSize)); 287 __ pop(live_regs, sp); 288 } 289 if (ShenandoahStoreValReadBarrier) { 290 read_barrier_impl(masm, dst); 291 } 292 } 293 294 void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type, 295 Register dst, Address src, Register tmp1, Register tmp_thread) { 296 bool on_oop = type == T_OBJECT || type == T_ARRAY; 297 bool in_heap = (decorators & IN_HEAP) != 0; 298 bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0; 299 bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0; 300 bool on_reference = on_weak || on_phantom; 301 302 if (in_heap) { 303 read_barrier_not_null(masm, src.base()); 304 } 305 306 BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread); 307 if (ShenandoahKeepAliveBarrier && on_oop && on_reference) { 308 __ enter(); 309 satb_write_barrier_pre(masm /* masm */, 310 noreg /* obj */, 311 dst /* pre_val */, 312 rthread /* thread */, 313 tmp1 /* tmp */, 314 true /* tosca_live */, 315 true /* expand_call */); 316 __ leave(); 317 } 318 } 319 320 void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type, 321 Address dst, Register val, Register tmp1, Register tmp2) { 322 bool on_oop = type == T_OBJECT || type == T_ARRAY; 323 bool in_heap = (decorators & IN_HEAP) != 0; 324 if (in_heap) { 325 write_barrier(masm, dst.base()); 326 } 327 if (!on_oop) { 328 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2); 329 return; 330 } 331 332 // flatten object address if needed 333 if (dst.index() == noreg && dst.offset() == 0) { 334 if (dst.base() != r3) { 335 __ mov(r3, dst.base()); 336 } 337 } else { 338 __ lea(r3, dst); 339 } 340 341 shenandoah_write_barrier_pre(masm, 342 r3 /* obj */, 343 tmp2 /* pre_val */, 344 rthread /* thread */, 345 tmp1 /* tmp */, 346 val != noreg /* tosca_live */, 347 false /* expand_call */); 348 349 if (val == noreg) { 350 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), noreg, noreg, noreg); 351 } else { 352 storeval_barrier(masm, val, tmp1); 353 // G1 barrier needs uncompressed oop for region cross check. 354 Register new_val = val; 355 if (UseCompressedOops) { 356 new_val = rscratch2; 357 __ mov(new_val, val); 358 } 359 BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), val, noreg, noreg); 360 } 361 362 } 363 364 void ShenandoahBarrierSetAssembler::obj_equals(MacroAssembler* masm, Register op1, Register op2) { 365 __ cmp(op1, op2); 366 if (ShenandoahAcmpBarrier) { 367 Label done; 368 __ br(Assembler::EQ, done); 369 // The object may have been evacuated, but we won't see it without a 370 // membar here. 371 __ membar(Assembler::LoadStore| Assembler::LoadLoad); 372 read_barrier(masm, op1); 373 read_barrier(masm, op2); 374 __ cmp(op1, op2); 375 __ bind(done); 376 } 377 } 378 379 void ShenandoahBarrierSetAssembler::tlab_allocate(MacroAssembler* masm, Register obj, 380 Register var_size_in_bytes, 381 int con_size_in_bytes, 382 Register t1, 383 Register t2, 384 Label& slow_case) { 385 386 assert_different_registers(obj, t2); 387 assert_different_registers(obj, var_size_in_bytes); 388 Register end = t2; 389 390 __ ldr(obj, Address(rthread, JavaThread::tlab_top_offset())); 391 if (var_size_in_bytes == noreg) { 392 __ lea(end, Address(obj, (int) (con_size_in_bytes + ShenandoahBrooksPointer::byte_size()))); 393 } else { 394 __ add(var_size_in_bytes, var_size_in_bytes, ShenandoahBrooksPointer::byte_size()); 395 __ lea(end, Address(obj, var_size_in_bytes)); 396 } 397 __ ldr(rscratch1, Address(rthread, JavaThread::tlab_end_offset())); 398 __ cmp(end, rscratch1); 399 __ br(Assembler::HI, slow_case); 400 401 // update the tlab top pointer 402 __ str(end, Address(rthread, JavaThread::tlab_top_offset())); 403 404 __ add(obj, obj, ShenandoahBrooksPointer::byte_size()); 405 __ str(obj, Address(obj, ShenandoahBrooksPointer::byte_offset())); 406 407 // recover var_size_in_bytes if necessary 408 if (var_size_in_bytes == end) { 409 __ sub(var_size_in_bytes, var_size_in_bytes, obj); 410 } 411 } 412 413 void ShenandoahBarrierSetAssembler::resolve(MacroAssembler* masm, DecoratorSet decorators, Register obj) { 414 bool oop_not_null = (decorators & IS_NOT_NULL) != 0; 415 bool is_write = (decorators & ACCESS_WRITE) != 0; 416 if (is_write) { 417 if (oop_not_null) { 418 write_barrier(masm, obj); 419 } else { 420 Label done; 421 __ cbz(obj, done); 422 write_barrier(masm, obj); 423 __ bind(done); 424 } 425 } else { 426 if (oop_not_null) { 427 read_barrier_not_null(masm, obj); 428 } else { 429 read_barrier(masm, obj); 430 } 431 } 432 } 433 434 void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val, 435 bool acquire, bool release, bool weak, bool is_cae, 436 Register result) { 437 Register tmp1 = rscratch1; 438 Register tmp2 = rscratch2; 439 bool is_narrow = UseCompressedOops; 440 Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword; 441 442 assert_different_registers(addr, expected, new_val, tmp1, tmp2); 443 444 Label retry, done, fail; 445 446 // CAS, using LL/SC pair. 447 __ bind(retry); 448 __ load_exclusive(tmp1, addr, size, acquire); 449 if (is_narrow) { 450 __ cmpw(tmp1, expected); 451 } else { 452 __ cmp(tmp1, expected); 453 } 454 __ br(Assembler::NE, fail); 455 __ store_exclusive(tmp2, new_val, addr, size, release); 456 if (weak) { 457 __ cmpw(tmp2, 0u); // If the store fails, return NE to our caller 458 } else { 459 __ cbnzw(tmp2, retry); 460 } 461 __ b(done); 462 463 __ bind(fail); 464 // Check if rb(expected)==rb(tmp1) 465 // Shuffle registers so that we have memory value ready for next expected. 466 __ mov(tmp2, expected); 467 __ mov(expected, tmp1); 468 if (is_narrow) { 469 __ decode_heap_oop(tmp1, tmp1); 470 __ decode_heap_oop(tmp2, tmp2); 471 } 472 read_barrier_impl(masm, tmp1); 473 read_barrier_impl(masm, tmp2); 474 __ cmp(tmp1, tmp2); 475 // Retry with expected now being the value we just loaded from addr. 476 __ br(Assembler::EQ, retry); 477 if (is_cae && is_narrow) { 478 // For cmp-and-exchange and narrow oops, we need to restore 479 // the compressed old-value. We moved it to 'expected' a few lines up. 480 __ mov(tmp1, expected); 481 } 482 __ bind(done); 483 484 if (is_cae) { 485 __ mov(result, tmp1); 486 } else { 487 __ cset(result, Assembler::EQ); 488 } 489 } 490 491 #ifdef COMPILER1 492 493 #undef __ 494 #define __ ce->masm()-> 495 496 void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) { 497 ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1(); 498 // At this point we know that marking is in progress. 499 // If do_load() is true then we have to emit the 500 // load of the previous value; otherwise it has already 501 // been loaded into _pre_val. 502 503 __ bind(*stub->entry()); 504 505 assert(stub->pre_val()->is_register(), "Precondition."); 506 507 Register pre_val_reg = stub->pre_val()->as_register(); 508 509 if (stub->do_load()) { 510 ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/, false /*unaligned*/); 511 } 512 __ cbz(pre_val_reg, *stub->continuation()); 513 ce->store_parameter(stub->pre_val()->as_register(), 0); 514 __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin())); 515 __ b(*stub->continuation()); 516 } 517 518 void ShenandoahBarrierSetAssembler::gen_write_barrier_stub(LIR_Assembler* ce, ShenandoahWriteBarrierStub* stub) { 519 520 Register obj = stub->obj()->as_register(); 521 Register res = stub->result()->as_register(); 522 523 Label done; 524 525 __ bind(*stub->entry()); 526 527 if (res != obj) { 528 __ mov(res, obj); 529 } 530 // Check for null. 531 if (stub->needs_null_check()) { 532 __ cbz(res, done); 533 } 534 535 write_barrier(ce->masm(), res); 536 537 __ bind(done); 538 __ b(*stub->continuation()); 539 } 540 541 #undef __ 542 543 #define __ sasm-> 544 545 void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) { 546 __ prologue("shenandoah_pre_barrier", false); 547 548 // arg0 : previous value of memory 549 550 BarrierSet* bs = BarrierSet::barrier_set(); 551 552 const Register pre_val = r0; 553 const Register thread = rthread; 554 const Register tmp = rscratch1; 555 556 Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset())); 557 Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset())); 558 559 Label done; 560 Label runtime; 561 562 // Is marking still active? 563 Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset())); 564 __ ldrb(tmp, gc_state); 565 __ mov(rscratch2, ShenandoahHeap::MARKING | ShenandoahHeap::TRAVERSAL); 566 __ tst(tmp, rscratch2); 567 __ br(Assembler::EQ, done); 568 569 // Can we store original value in the thread's buffer? 570 __ ldr(tmp, queue_index); 571 __ cbz(tmp, runtime); 572 573 __ sub(tmp, tmp, wordSize); 574 __ str(tmp, queue_index); 575 __ ldr(rscratch2, buffer); 576 __ add(tmp, tmp, rscratch2); 577 __ load_parameter(0, rscratch2); 578 __ str(rscratch2, Address(tmp, 0)); 579 __ b(done); 580 581 __ bind(runtime); 582 __ push_call_clobbered_registers(); 583 __ load_parameter(0, pre_val); 584 __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread); 585 __ pop_call_clobbered_registers(); 586 __ bind(done); 587 588 __ epilogue(); 589 } 590 591 #undef __ 592 593 #endif // COMPILER1 594 595 address ShenandoahBarrierSetAssembler::shenandoah_wb() { 596 assert(_shenandoah_wb != NULL, "need write barrier stub"); 597 return _shenandoah_wb; 598 } 599 600 #define __ cgen->assembler()-> 601 602 // Shenandoah write barrier. 603 // 604 // Input: 605 // r0: OOP to evacuate. Not null. 606 // 607 // Output: 608 // r0: Pointer to evacuated OOP. 609 // 610 // Trash rscratch1, rscratch2. Preserve everything else. 611 address ShenandoahBarrierSetAssembler::generate_shenandoah_wb(StubCodeGenerator* cgen) { 612 613 __ align(6); 614 StubCodeMark mark(cgen, "StubRoutines", "shenandoah_wb"); 615 address start = __ pc(); 616 617 Label work; 618 __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr()); 619 __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint()); 620 __ ldrb(rscratch2, Address(rscratch2, rscratch1)); 621 __ tbnz(rscratch2, 0, work); 622 __ ret(lr); 623 __ bind(work); 624 625 Register obj = r0; 626 627 __ enter(); // required for proper stackwalking of RuntimeStub frame 628 629 __ push_call_clobbered_registers(); 630 631 __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_JRT)); 632 __ blrt(lr, 1, 0, MacroAssembler::ret_type_integral); 633 __ mov(rscratch1, obj); 634 __ pop_call_clobbered_registers(); 635 __ mov(obj, rscratch1); 636 637 __ leave(); // required for proper stackwalking of RuntimeStub frame 638 __ ret(lr); 639 640 return start; 641 } 642 643 #undef __ 644 645 void ShenandoahBarrierSetAssembler::barrier_stubs_init() { 646 if (ShenandoahWriteBarrier || ShenandoahStoreValEnqueueBarrier) { 647 int stub_code_size = 2048; 648 ResourceMark rm; 649 BufferBlob* bb = BufferBlob::create("shenandoah_barrier_stubs", stub_code_size); 650 CodeBuffer buf(bb); 651 StubCodeGenerator cgen(&buf); 652 _shenandoah_wb = generate_shenandoah_wb(&cgen); 653 } 654 }