8214259: Implementation: JEP 189: Shenandoah: A Low-Pause-Time Garbage Collector (Experimental)
Reviewed-by: kvn, roland, shade, coleenp, lmesnik, pliden, jgeorge, ihse, erikj
Contributed-by: Christine Flood <chf@redhat.com>, Aleksey Shipilev <shade@redhat.com>, Roland Westrelin <rwestrel@redhat.com>, Zhenygu Gu <zgu@redhat.com>, Andrew Haley <aph@redhat.com>, Andrew Dinn <adinn@redhat.com>, Mario Torre <mtorre@redhat.com>, Roman Kennke <rkennke@redhat.com>
/*
* Copyright (c) 2018, Red Hat, Inc. All rights reserved.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "c1/c1_LIRAssembler.hpp"
#include "c1/c1_MacroAssembler.hpp"
#include "gc/shenandoah/shenandoahBarrierSet.hpp"
#include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
#include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
void LIR_OpShenandoahCompareAndSwap::emit_code(LIR_Assembler* masm) {
Register addr = _addr->as_register_lo();
Register newval = _new_value->as_register();
Register cmpval = _cmp_value->as_register();
Register tmp1 = _tmp1->as_register();
Register tmp2 = _tmp2->as_register();
assert(cmpval == rax, "wrong register");
assert(newval != NULL, "new val must be register");
assert(cmpval != newval, "cmp and new values must be in different registers");
assert(cmpval != addr, "cmp and addr must be in different registers");
assert(newval != addr, "new value and addr must be in different registers");
ShenandoahBarrierSet::assembler()->cmpxchg_oop(masm->masm(), NULL, Address(addr, 0), cmpval, newval, true, true, tmp1, tmp2);
}
#ifdef ASSERT
#define __ gen->lir(__FILE__, __LINE__)->
#else
#define __ gen->lir()->
#endif
LIR_Opr ShenandoahBarrierSetC1::atomic_cmpxchg_at_resolved(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
if (access.is_oop()) {
LIRGenerator* gen = access.gen();
if (ShenandoahSATBBarrier) {
pre_barrier(gen, access.access_emit_info(), access.decorators(), access.resolved_addr(),
LIR_OprFact::illegalOpr /* pre_val */);
}
if (ShenandoahCASBarrier) {
cmp_value.load_item_force(FrameMap::rax_oop_opr);
new_value.load_item();
LIR_Opr t1 = gen->new_register(T_OBJECT);
LIR_Opr t2 = gen->new_register(T_OBJECT);
LIR_Opr addr = access.resolved_addr()->as_address_ptr()->base();
__ append(new LIR_OpShenandoahCompareAndSwap(addr, cmp_value.result(), new_value.result(), t1, t2, LIR_OprFact::illegalOpr));
LIR_Opr result = gen->new_register(T_INT);
__ cmove(lir_cond_equal, LIR_OprFact::intConst(1), LIR_OprFact::intConst(0),
result, T_INT);
return result;
}
}
return BarrierSetC1::atomic_cmpxchg_at_resolved(access, cmp_value, new_value);
}
LIR_Opr ShenandoahBarrierSetC1::atomic_xchg_at_resolved(LIRAccess& access, LIRItem& value) {
LIRGenerator* gen = access.gen();
BasicType type = access.type();
LIR_Opr result = gen->new_register(type);
value.load_item();
LIR_Opr value_opr = value.result();
if (access.is_oop()) {
value_opr = storeval_barrier(access.gen(), value_opr, access.access_emit_info(), access.decorators());
}
// Because we want a 2-arg form of xchg and xadd
__ move(value_opr, result);
assert(type == T_INT || type == T_OBJECT || type == T_ARRAY LP64_ONLY( || type == T_LONG ), "unexpected type");
__ xchg(access.resolved_addr(), result, result, LIR_OprFact::illegalOpr);
if (access.is_oop()) {
if (ShenandoahSATBBarrier) {
pre_barrier(access.gen(), access.access_emit_info(), access.decorators(), LIR_OprFact::illegalOpr,
result /* pre_val */);
}
}
return result;
}