1 /*
2 * Copyright (c) 2018, 2025, Oracle and/or its affiliates. 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 *
114 __ add(start, start, scratch);
115
116 __ bind(loop);
117 if (UseCondCardMark) {
118 __ ldrb(scratch, Address(start, count));
119 // Instead of loading clean_card_val and comparing, we exploit the fact that
120 // the LSB of non-clean cards is always 0, and the LSB of clean cards 1.
121 __ tbz(scratch, 0, next);
122 }
123 static_assert(G1CardTable::dirty_card_val() == 0, "must be to use zr");
124 __ strb(zr, Address(start, count));
125 __ bind(next);
126 __ subs(count, count, 1);
127 __ br(Assembler::GE, loop);
128
129 __ bind(done);
130 }
131
132 static void generate_queue_test_and_insertion(MacroAssembler* masm, ByteSize index_offset, ByteSize buffer_offset, Label& runtime,
133 const Register thread, const Register value, const Register temp1, const Register temp2) {
134 // Can we store a value in the given thread's buffer?
135 // (The index field is typed as size_t.)
136 __ ldr(temp1, Address(thread, in_bytes(index_offset))); // temp1 := *(index address)
137 __ cbz(temp1, runtime); // jump to runtime if index == 0 (full buffer)
138 // The buffer is not full, store value into it.
139 __ sub(temp1, temp1, wordSize); // temp1 := next index
140 __ str(temp1, Address(thread, in_bytes(index_offset))); // *(index address) := next index
141 __ ldr(temp2, Address(thread, in_bytes(buffer_offset))); // temp2 := buffer address
142 __ str(value, Address(temp2, temp1)); // *(buffer address + next index) := value
143 }
144
145 static void generate_pre_barrier_fast_path(MacroAssembler* masm,
146 const Register thread,
147 const Register tmp1) {
148 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
149 // Is marking active?
150 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
151 __ ldrw(tmp1, in_progress);
152 } else {
153 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
187 bool expand_call) {
188 // If expand_call is true then we expand the call_VM_leaf macro
189 // directly to skip generating the check by
190 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
191
192 assert(thread == rthread, "must be");
193
194 Label done;
195 Label runtime;
196
197 assert_different_registers(obj, pre_val, tmp1, tmp2);
198 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
199
200 generate_pre_barrier_fast_path(masm, thread, tmp1);
201 // If marking is not active (*(mark queue active address) == 0), jump to done
202 __ cbzw(tmp1, done);
203 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp1, tmp2, done, runtime);
204
205 __ bind(runtime);
206
207 __ push_call_clobbered_registers();
208
209 // Calling the runtime using the regular call_VM_leaf mechanism generates
210 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
211 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == nullptr.
212 //
213 // If we care generating the pre-barrier without a frame (e.g. in the
214 // intrinsified Reference.get() routine) then rfp might be pointing to
215 // the caller frame and so this check will most likely fail at runtime.
216 //
217 // Expanding the call directly bypasses the generation of the check.
218 // So when we do not have have a full interpreter frame on the stack
219 // expand_call should be passed true.
220
221 if (expand_call) {
222 assert(pre_val != c_rarg1, "smashed arg");
223 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
224 } else {
225 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
226 }
349 CardTableBarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
350 if (on_oop && on_reference) {
351 // LR is live. It must be saved around calls.
352 __ enter(/*strip_ret_addr*/true); // barrier may call runtime
353 // Generate the G1 pre-barrier code to log the value of
354 // the referent field in an SATB buffer.
355 g1_write_barrier_pre(masm /* masm */,
356 noreg /* obj */,
357 dst /* pre_val */,
358 rthread /* thread */,
359 tmp1 /* tmp1 */,
360 tmp2 /* tmp2 */,
361 true /* tosca_live */,
362 true /* expand_call */);
363 __ leave();
364 }
365 }
366
367 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
368 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
369 // flatten object address if needed
370 if (dst.index() == noreg && dst.offset() == 0) {
371 if (dst.base() != tmp3) {
372 __ mov(tmp3, dst.base());
373 }
374 } else {
375 __ lea(tmp3, dst);
376 }
377
378 g1_write_barrier_pre(masm,
379 tmp3 /* obj */,
380 tmp2 /* pre_val */,
381 rthread /* thread */,
382 tmp1 /* tmp1 */,
383 rscratch2 /* tmp2 */,
384 val != noreg /* tosca_live */,
385 false /* expand_call */);
386
387 if (val == noreg) {
388 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), noreg, noreg, noreg, noreg);
389 } else {
390 // G1 barrier needs uncompressed oop for region cross check.
391 Register new_val = val;
392 if (UseCompressedOops) {
393 new_val = rscratch2;
394 __ mov(new_val, val);
395 }
396 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), val, noreg, noreg, noreg);
397 g1_write_barrier_post(masm,
398 tmp3 /* store_adr */,
399 new_val /* new_val */,
400 rthread /* thread */,
401 tmp1 /* tmp1 */,
402 tmp2 /* tmp2 */);
403 }
404
405 }
406
407 #ifdef COMPILER1
408
409 #undef __
410 #define __ ce->masm()->
411
412 void G1BarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, G1PreBarrierStub* stub) {
413 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
414 // At this point we know that marking is in progress.
415 // If do_load() is true then we have to emit the
416 // load of the previous value; otherwise it has already
417 // been loaded into _pre_val.
418
419 __ bind(*stub->entry());
420
421 assert(stub->pre_val()->is_register(), "Precondition.");
422
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1 /*
2 * Copyright (c) 2018, 2026, Oracle and/or its affiliates. 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 *
114 __ add(start, start, scratch);
115
116 __ bind(loop);
117 if (UseCondCardMark) {
118 __ ldrb(scratch, Address(start, count));
119 // Instead of loading clean_card_val and comparing, we exploit the fact that
120 // the LSB of non-clean cards is always 0, and the LSB of clean cards 1.
121 __ tbz(scratch, 0, next);
122 }
123 static_assert(G1CardTable::dirty_card_val() == 0, "must be to use zr");
124 __ strb(zr, Address(start, count));
125 __ bind(next);
126 __ subs(count, count, 1);
127 __ br(Assembler::GE, loop);
128
129 __ bind(done);
130 }
131
132 static void generate_queue_test_and_insertion(MacroAssembler* masm, ByteSize index_offset, ByteSize buffer_offset, Label& runtime,
133 const Register thread, const Register value, const Register temp1, const Register temp2) {
134 assert_different_registers(value, temp1, temp2);
135 // Can we store a value in the given thread's buffer?
136 // (The index field is typed as size_t.)
137 __ ldr(temp1, Address(thread, in_bytes(index_offset))); // temp1 := *(index address)
138 __ cbz(temp1, runtime); // jump to runtime if index == 0 (full buffer)
139 // The buffer is not full, store value into it.
140 __ sub(temp1, temp1, wordSize); // temp1 := next index
141 __ str(temp1, Address(thread, in_bytes(index_offset))); // *(index address) := next index
142 __ ldr(temp2, Address(thread, in_bytes(buffer_offset))); // temp2 := buffer address
143 __ str(value, Address(temp2, temp1)); // *(buffer address + next index) := value
144 }
145
146 static void generate_pre_barrier_fast_path(MacroAssembler* masm,
147 const Register thread,
148 const Register tmp1) {
149 Address in_progress(thread, in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()));
150 // Is marking active?
151 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
152 __ ldrw(tmp1, in_progress);
153 } else {
154 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
188 bool expand_call) {
189 // If expand_call is true then we expand the call_VM_leaf macro
190 // directly to skip generating the check by
191 // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp.
192
193 assert(thread == rthread, "must be");
194
195 Label done;
196 Label runtime;
197
198 assert_different_registers(obj, pre_val, tmp1, tmp2);
199 assert(pre_val != noreg && tmp1 != noreg && tmp2 != noreg, "expecting a register");
200
201 generate_pre_barrier_fast_path(masm, thread, tmp1);
202 // If marking is not active (*(mark queue active address) == 0), jump to done
203 __ cbzw(tmp1, done);
204 generate_pre_barrier_slow_path(masm, obj, pre_val, thread, tmp1, tmp2, done, runtime);
205
206 __ bind(runtime);
207
208 // save the live input values
209 RegSet saved = RegSet::of(pre_val);
210 FloatRegSet fsaved;
211
212 // Barriers might be emitted when converting between (scalarized) calling
213 // conventions for inline types. Save all argument registers before calling
214 // into the runtime.
215
216 assert_different_registers(rscratch1, pre_val); // push_call_clobbered_registers trashes rscratch1
217 __ push_call_clobbered_registers();
218
219 // Calling the runtime using the regular call_VM_leaf mechanism generates
220 // code (generated by InterpreterMacroAssember::call_VM_leaf_base)
221 // that checks that the *(rfp+frame::interpreter_frame_last_sp) == nullptr.
222 //
223 // If we care generating the pre-barrier without a frame (e.g. in the
224 // intrinsified Reference.get() routine) then rfp might be pointing to
225 // the caller frame and so this check will most likely fail at runtime.
226 //
227 // Expanding the call directly bypasses the generation of the check.
228 // So when we do not have have a full interpreter frame on the stack
229 // expand_call should be passed true.
230
231 if (expand_call) {
232 assert(pre_val != c_rarg1, "smashed arg");
233 __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
234 } else {
235 __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), pre_val, thread);
236 }
359 CardTableBarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp2);
360 if (on_oop && on_reference) {
361 // LR is live. It must be saved around calls.
362 __ enter(/*strip_ret_addr*/true); // barrier may call runtime
363 // Generate the G1 pre-barrier code to log the value of
364 // the referent field in an SATB buffer.
365 g1_write_barrier_pre(masm /* masm */,
366 noreg /* obj */,
367 dst /* pre_val */,
368 rthread /* thread */,
369 tmp1 /* tmp1 */,
370 tmp2 /* tmp2 */,
371 true /* tosca_live */,
372 true /* expand_call */);
373 __ leave();
374 }
375 }
376
377 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
378 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
379
380 bool in_heap = (decorators & IN_HEAP) != 0;
381 bool as_normal = (decorators & AS_NORMAL) != 0;
382 bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0;
383
384 bool needs_pre_barrier = as_normal && !dest_uninitialized;
385 bool needs_post_barrier = (val != noreg && in_heap);
386
387 assert_different_registers(val, tmp1, tmp2, tmp3);
388
389 // flatten object address if needed
390 if (dst.index() == noreg && dst.offset() == 0) {
391 if (dst.base() != tmp3) {
392 __ mov(tmp3, dst.base());
393 }
394 } else {
395 __ lea(tmp3, dst);
396 }
397
398 if (needs_pre_barrier) {
399 g1_write_barrier_pre(masm,
400 tmp3 /* obj */,
401 tmp2 /* pre_val */,
402 rthread /* thread */,
403 tmp1 /* tmp1 */,
404 rscratch2 /* tmp2 */,
405 val != noreg /* tosca_live */,
406 false /* expand_call */);
407 }
408
409 if (val == noreg) {
410 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), noreg, noreg, noreg, noreg);
411 } else {
412 // G1 barrier needs uncompressed oop for region cross check.
413 Register new_val = val;
414 if (needs_post_barrier) {
415 if (UseCompressedOops) {
416 new_val = rscratch2;
417 __ mov(new_val, val);
418 }
419 }
420
421 BarrierSetAssembler::store_at(masm, decorators, type, Address(tmp3, 0), val, noreg, noreg, noreg);
422 if (needs_post_barrier) {
423 g1_write_barrier_post(masm,
424 tmp3 /* store_adr */,
425 new_val /* new_val */,
426 rthread /* thread */,
427 tmp1 /* tmp1 */,
428 tmp2 /* tmp2 */);
429 }
430 }
431
432 }
433
434 #ifdef COMPILER1
435
436 #undef __
437 #define __ ce->masm()->
438
439 void G1BarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, G1PreBarrierStub* stub) {
440 G1BarrierSetC1* bs = (G1BarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1();
441 // At this point we know that marking is in progress.
442 // If do_load() is true then we have to emit the
443 // load of the previous value; otherwise it has already
444 // been loaded into _pre_val.
445
446 __ bind(*stub->entry());
447
448 assert(stub->pre_val()->is_register(), "Precondition.");
449
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