--- /dev/null 2020-01-17 11:46:19.065201212 +0100 +++ new/src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp 2020-01-17 17:09:27.426132831 +0100 @@ -0,0 +1,679 @@ +/* + * Copyright (c) 2018, 2019, 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 "gc/shenandoah/shenandoahBarrierSetAssembler.hpp" +#include "gc/shenandoah/shenandoahForwarding.hpp" +#include "gc/shenandoah/shenandoahHeap.hpp" +#include "gc/shenandoah/shenandoahHeapRegion.hpp" +#include "gc/shenandoah/shenandoahHeuristics.hpp" +#include "gc/shenandoah/shenandoahRuntime.hpp" +#include "gc/shenandoah/shenandoahThreadLocalData.hpp" +#include "interpreter/interpreter.hpp" +#include "interpreter/interp_masm.hpp" +#include "runtime/sharedRuntime.hpp" +#include "runtime/thread.hpp" +#ifdef COMPILER1 +#include "c1/c1_LIRAssembler.hpp" +#include "c1/c1_MacroAssembler.hpp" +#include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp" +#endif + +#define __ masm-> + +address ShenandoahBarrierSetAssembler::_shenandoah_lrb = NULL; + +void ShenandoahBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, bool is_oop, + Register src, Register dst, Register count, RegSet saved_regs) { + if (is_oop) { + bool dest_uninitialized = (decorators & IS_DEST_UNINITIALIZED) != 0; + if ((ShenandoahSATBBarrier && !dest_uninitialized) || ShenandoahLoadRefBarrier) { + + Label done; + + // Avoid calling runtime if count == 0 + __ cbz(count, done); + + // Is marking active? + Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset())); + __ ldrb(rscratch1, gc_state); + if (dest_uninitialized) { + __ tbz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, done); + } else { + __ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING); + __ tst(rscratch1, rscratch2); + __ br(Assembler::EQ, done); + } + + __ push(saved_regs, sp); + if (UseCompressedOops) { + if (dest_uninitialized) { + __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_narrow_oop_entry), src, dst, count); + } else { + __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_narrow_oop_entry), src, dst, count); + } + } else { + if (dest_uninitialized) { + __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_duinit_oop_entry), src, dst, count); + } else { + __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_array_pre_oop_entry), src, dst, count); + } + } + __ pop(saved_regs, sp); + __ bind(done); + } + } +} + +void ShenandoahBarrierSetAssembler::shenandoah_write_barrier_pre(MacroAssembler* masm, + Register obj, + Register pre_val, + Register thread, + Register tmp, + bool tosca_live, + bool expand_call) { + if (ShenandoahSATBBarrier) { + satb_write_barrier_pre(masm, obj, pre_val, thread, tmp, tosca_live, expand_call); + } +} + +void ShenandoahBarrierSetAssembler::satb_write_barrier_pre(MacroAssembler* masm, + Register obj, + Register pre_val, + Register thread, + Register tmp, + bool tosca_live, + bool expand_call) { + // If expand_call is true then we expand the call_VM_leaf macro + // directly to skip generating the check by + // InterpreterMacroAssembler::call_VM_leaf_base that checks _last_sp. + + assert(thread == rthread, "must be"); + + Label done; + Label runtime; + + assert_different_registers(obj, pre_val, tmp, rscratch1); + assert(pre_val != noreg && tmp != noreg, "expecting a register"); + + Address in_progress(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset())); + Address index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset())); + Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset())); + + // Is marking active? + if (in_bytes(ShenandoahSATBMarkQueue::byte_width_of_active()) == 4) { + __ ldrw(tmp, in_progress); + } else { + assert(in_bytes(ShenandoahSATBMarkQueue::byte_width_of_active()) == 1, "Assumption"); + __ ldrb(tmp, in_progress); + } + __ cbzw(tmp, done); + + // Do we need to load the previous value? + if (obj != noreg) { + __ load_heap_oop(pre_val, Address(obj, 0), noreg, noreg, AS_RAW); + } + + // Is the previous value null? + __ cbz(pre_val, done); + + // Can we store original value in the thread's buffer? + // Is index == 0? + // (The index field is typed as size_t.) + + __ ldr(tmp, index); // tmp := *index_adr + __ cbz(tmp, runtime); // tmp == 0? + // If yes, goto runtime + + __ sub(tmp, tmp, wordSize); // tmp := tmp - wordSize + __ str(tmp, index); // *index_adr := tmp + __ ldr(rscratch1, buffer); + __ add(tmp, tmp, rscratch1); // tmp := tmp + *buffer_adr + + // Record the previous value + __ str(pre_val, Address(tmp, 0)); + __ b(done); + + __ bind(runtime); + // save the live input values + RegSet saved = RegSet::of(pre_val); + if (tosca_live) saved += RegSet::of(r0); + if (obj != noreg) saved += RegSet::of(obj); + + __ push(saved, sp); + + // Calling the runtime using the regular call_VM_leaf mechanism generates + // code (generated by InterpreterMacroAssember::call_VM_leaf_base) + // that checks that the *(rfp+frame::interpreter_frame_last_sp) == NULL. + // + // If we care generating the pre-barrier without a frame (e.g. in the + // intrinsified Reference.get() routine) then ebp might be pointing to + // the caller frame and so this check will most likely fail at runtime. + // + // Expanding the call directly bypasses the generation of the check. + // So when we do not have have a full interpreter frame on the stack + // expand_call should be passed true. + + if (expand_call) { + assert(pre_val != c_rarg1, "smashed arg"); + __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread); + } else { + __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread); + } + + __ pop(saved, sp); + + __ bind(done); +} + +void ShenandoahBarrierSetAssembler::resolve_forward_pointer(MacroAssembler* masm, Register dst, Register tmp) { + assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled"); + Label is_null; + __ cbz(dst, is_null); + resolve_forward_pointer_not_null(masm, dst, tmp); + __ bind(is_null); +} + +// IMPORTANT: This must preserve all registers, even rscratch1 and rscratch2, except those explicitely +// passed in. +void ShenandoahBarrierSetAssembler::resolve_forward_pointer_not_null(MacroAssembler* masm, Register dst, Register tmp) { + assert(ShenandoahLoadRefBarrier || ShenandoahCASBarrier, "Should be enabled"); + // The below loads the mark word, checks if the lowest two bits are + // set, and if so, clear the lowest two bits and copy the result + // to dst. Otherwise it leaves dst alone. + // Implementing this is surprisingly awkward. I do it here by: + // - Inverting the mark word + // - Test lowest two bits == 0 + // - If so, set the lowest two bits + // - Invert the result back, and copy to dst + + bool borrow_reg = (tmp == noreg); + if (borrow_reg) { + // No free registers available. Make one useful. + tmp = rscratch1; + if (tmp == dst) { + tmp = rscratch2; + } + __ push(RegSet::of(tmp), sp); + } + + assert_different_registers(tmp, dst); + + Label done; + __ ldr(tmp, Address(dst, oopDesc::mark_offset_in_bytes())); + __ eon(tmp, tmp, zr); + __ ands(zr, tmp, markOopDesc::lock_mask_in_place); + __ br(Assembler::NE, done); + __ orr(tmp, tmp, markOopDesc::marked_value); + __ eon(dst, tmp, zr); + __ bind(done); + + if (borrow_reg) { + __ pop(RegSet::of(tmp), sp); + } +} + +void ShenandoahBarrierSetAssembler::load_reference_barrier_not_null(MacroAssembler* masm, Register dst, Address load_addr) { + assert(ShenandoahLoadRefBarrier, "Should be enabled"); + assert(dst != rscratch2, "need rscratch2"); + assert_different_registers(load_addr.base(), load_addr.index(), rscratch1, rscratch2); + + Label done; + __ enter(); + Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset())); + __ ldrb(rscratch2, gc_state); + + // Check for heap stability + __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, done); + + // use r1 for load address + Register result_dst = dst; + if (dst == r1) { + __ mov(rscratch1, dst); + dst = rscratch1; + } + + // Save r0 and r1, unless it is an output register + RegSet to_save = RegSet::of(r0, r1) - result_dst; + __ push(to_save, sp); + __ lea(r1, load_addr); + __ mov(r0, dst); + + __ far_call(RuntimeAddress(CAST_FROM_FN_PTR(address, ShenandoahBarrierSetAssembler::shenandoah_lrb()))); + + __ mov(result_dst, r0); + __ pop(to_save, sp); + + __ bind(done); + __ leave(); +} + +void ShenandoahBarrierSetAssembler::storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) { + if (ShenandoahStoreValEnqueueBarrier) { + // Save possibly live regs. + RegSet live_regs = RegSet::range(r0, r4) - dst; + __ push(live_regs, sp); + __ strd(v0, __ pre(sp, 2 * -wordSize)); + + satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false); + + // Restore possibly live regs. + __ ldrd(v0, __ post(sp, 2 * wordSize)); + __ pop(live_regs, sp); + } +} + +void ShenandoahBarrierSetAssembler::load_reference_barrier(MacroAssembler* masm, Register dst, Address load_addr) { + if (ShenandoahLoadRefBarrier) { + Label is_null; + __ cbz(dst, is_null); + load_reference_barrier_not_null(masm, dst, load_addr); + __ bind(is_null); + } +} + +void ShenandoahBarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type, + Register dst, Address src, Register tmp1, Register tmp_thread) { + // 1: non-reference load, no additional barrier is needed + if (!is_reference_type(type)) { + BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread); + return; + } + + // 2: load a reference from src location and apply LRB if needed + if (ShenandoahBarrierSet::need_load_reference_barrier(decorators, type)) { + Register result_dst = dst; + + // Preserve src location for LRB + if (dst == src.base() || dst == src.index()) { + dst = rscratch1; + } + assert_different_registers(dst, src.base(), src.index()); + + BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread); + + load_reference_barrier(masm, dst, src); + + if (dst != result_dst) { + __ mov(result_dst, dst); + dst = result_dst; + } + } else { + BarrierSetAssembler::load_at(masm, decorators, type, dst, src, tmp1, tmp_thread); + } + + // 3: apply keep-alive barrier if needed + if (ShenandoahBarrierSet::need_keep_alive_barrier(decorators, type)) { + __ enter(); + satb_write_barrier_pre(masm /* masm */, + noreg /* obj */, + dst /* pre_val */, + rthread /* thread */, + tmp1 /* tmp */, + true /* tosca_live */, + true /* expand_call */); + __ leave(); + } +} + +void ShenandoahBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type, + Address dst, Register val, Register tmp1, Register tmp2) { + bool on_oop = type == T_OBJECT || type == T_ARRAY; + if (!on_oop) { + BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2); + return; + } + + // flatten object address if needed + if (dst.index() == noreg && dst.offset() == 0) { + if (dst.base() != r3) { + __ mov(r3, dst.base()); + } + } else { + __ lea(r3, dst); + } + + shenandoah_write_barrier_pre(masm, + r3 /* obj */, + tmp2 /* pre_val */, + rthread /* thread */, + tmp1 /* tmp */, + val != noreg /* tosca_live */, + false /* expand_call */); + + if (val == noreg) { + BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), noreg, noreg, noreg); + } else { + storeval_barrier(masm, val, tmp1); + // G1 barrier needs uncompressed oop for region cross check. + Register new_val = val; + if (UseCompressedOops) { + new_val = rscratch2; + __ mov(new_val, val); + } + BarrierSetAssembler::store_at(masm, decorators, type, Address(r3, 0), val, noreg, noreg); + } + +} + +void ShenandoahBarrierSetAssembler::try_resolve_jobject_in_native(MacroAssembler* masm, Register jni_env, + Register obj, Register tmp, Label& slowpath) { + Label done; + // Resolve jobject + BarrierSetAssembler::try_resolve_jobject_in_native(masm, jni_env, obj, tmp, slowpath); + + // Check for null. + __ cbz(obj, done); + + assert(obj != rscratch2, "need rscratch2"); + Address gc_state(jni_env, ShenandoahThreadLocalData::gc_state_offset() - JavaThread::jni_environment_offset()); + __ lea(rscratch2, gc_state); + __ ldrb(rscratch2, Address(rscratch2)); + + // Check for heap in evacuation phase + __ tbnz(rscratch2, ShenandoahHeap::EVACUATION_BITPOS, slowpath); + + __ bind(done); +} + + +void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val, + bool acquire, bool release, bool weak, bool is_cae, + Register result) { + Register tmp1 = rscratch1; + Register tmp2 = rscratch2; + bool is_narrow = UseCompressedOops; + Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword; + + assert_different_registers(addr, expected, new_val, tmp1, tmp2); + + Label retry, done, fail; + + // CAS, using LL/SC pair. + __ bind(retry); + __ load_exclusive(tmp1, addr, size, acquire); + if (is_narrow) { + __ cmpw(tmp1, expected); + } else { + __ cmp(tmp1, expected); + } + __ br(Assembler::NE, fail); + __ store_exclusive(tmp2, new_val, addr, size, release); + if (weak) { + __ cmpw(tmp2, 0u); // If the store fails, return NE to our caller + } else { + __ cbnzw(tmp2, retry); + } + __ b(done); + + __ bind(fail); + // Check if rb(expected)==rb(tmp1) + // Shuffle registers so that we have memory value ready for next expected. + __ mov(tmp2, expected); + __ mov(expected, tmp1); + if (is_narrow) { + __ decode_heap_oop(tmp1, tmp1); + __ decode_heap_oop(tmp2, tmp2); + } + resolve_forward_pointer(masm, tmp1); + resolve_forward_pointer(masm, tmp2); + __ cmp(tmp1, tmp2); + // Retry with expected now being the value we just loaded from addr. + __ br(Assembler::EQ, retry); + if (is_cae && is_narrow) { + // For cmp-and-exchange and narrow oops, we need to restore + // the compressed old-value. We moved it to 'expected' a few lines up. + __ mov(tmp1, expected); + } + __ bind(done); + + if (is_cae) { + __ mov(result, tmp1); + } else { + __ cset(result, Assembler::EQ); + } +} + +#undef __ + +#ifdef COMPILER1 + +#define __ ce->masm()-> + +void ShenandoahBarrierSetAssembler::gen_pre_barrier_stub(LIR_Assembler* ce, ShenandoahPreBarrierStub* stub) { + ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1(); + // At this point we know that marking is in progress. + // If do_load() is true then we have to emit the + // load of the previous value; otherwise it has already + // been loaded into _pre_val. + + __ bind(*stub->entry()); + + assert(stub->pre_val()->is_register(), "Precondition."); + + Register pre_val_reg = stub->pre_val()->as_register(); + + if (stub->do_load()) { + ce->mem2reg(stub->addr(), stub->pre_val(), T_OBJECT, stub->patch_code(), stub->info(), false /*wide*/, false /*unaligned*/); + } + __ cbz(pre_val_reg, *stub->continuation()); + ce->store_parameter(stub->pre_val()->as_register(), 0); + __ far_call(RuntimeAddress(bs->pre_barrier_c1_runtime_code_blob()->code_begin())); + __ b(*stub->continuation()); +} + +void ShenandoahBarrierSetAssembler::gen_load_reference_barrier_stub(LIR_Assembler* ce, ShenandoahLoadReferenceBarrierStub* stub) { + ShenandoahBarrierSetC1* bs = (ShenandoahBarrierSetC1*)BarrierSet::barrier_set()->barrier_set_c1(); + __ bind(*stub->entry()); + + Register obj = stub->obj()->as_register(); + Register res = stub->result()->as_register(); + Register addr = stub->addr()->as_pointer_register(); + Register tmp1 = stub->tmp1()->as_register(); + Register tmp2 = stub->tmp2()->as_register(); + + assert(res == r0, "result must arrive in r0"); + + if (res != obj) { + __ mov(res, obj); + } + + // Check for null. + __ cbz(res, *stub->continuation()); + + // Check for object in cset. + __ mov(tmp2, ShenandoahHeap::in_cset_fast_test_addr()); + __ lsr(tmp1, res, ShenandoahHeapRegion::region_size_bytes_shift_jint()); + __ ldrb(tmp2, Address(tmp2, tmp1)); + __ cbz(tmp2, *stub->continuation()); + + // Check if object is already forwarded. + Label slow_path; + __ ldr(tmp1, Address(res, oopDesc::mark_offset_in_bytes())); + __ eon(tmp1, tmp1, zr); + __ ands(zr, tmp1, markOopDesc::lock_mask_in_place); + __ br(Assembler::NE, slow_path); + + // Decode forwarded object. + __ orr(tmp1, tmp1, markOopDesc::marked_value); + __ eon(res, tmp1, zr); + __ b(*stub->continuation()); + + __ bind(slow_path); + ce->store_parameter(res, 0); + ce->store_parameter(addr, 1); + __ far_call(RuntimeAddress(bs->load_reference_barrier_rt_code_blob()->code_begin())); + + __ b(*stub->continuation()); +} + +#undef __ + +#define __ sasm-> + +void ShenandoahBarrierSetAssembler::generate_c1_pre_barrier_runtime_stub(StubAssembler* sasm) { + __ prologue("shenandoah_pre_barrier", false); + + // arg0 : previous value of memory + + BarrierSet* bs = BarrierSet::barrier_set(); + + const Register pre_val = r0; + const Register thread = rthread; + const Register tmp = rscratch1; + + Address queue_index(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset())); + Address buffer(thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset())); + + Label done; + Label runtime; + + // Is marking still active? + Address gc_state(thread, in_bytes(ShenandoahThreadLocalData::gc_state_offset())); + __ ldrb(tmp, gc_state); + __ mov(rscratch2, ShenandoahHeap::MARKING | ShenandoahHeap::TRAVERSAL); + __ tst(tmp, rscratch2); + __ br(Assembler::EQ, done); + + // Can we store original value in the thread's buffer? + __ ldr(tmp, queue_index); + __ cbz(tmp, runtime); + + __ sub(tmp, tmp, wordSize); + __ str(tmp, queue_index); + __ ldr(rscratch2, buffer); + __ add(tmp, tmp, rscratch2); + __ load_parameter(0, rscratch2); + __ str(rscratch2, Address(tmp, 0)); + __ b(done); + + __ bind(runtime); + __ push_call_clobbered_registers(); + __ load_parameter(0, pre_val); + __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_ref_field_pre_entry), pre_val, thread); + __ pop_call_clobbered_registers(); + __ bind(done); + + __ epilogue(); +} + +void ShenandoahBarrierSetAssembler::generate_c1_load_reference_barrier_runtime_stub(StubAssembler* sasm) { + __ prologue("shenandoah_load_reference_barrier", false); + // arg0 : object to be resolved + + __ push_call_clobbered_registers(); + __ load_parameter(0, r0); + __ load_parameter(1, r1); + if (UseCompressedOops) { + __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow)); + } else { + __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier)); + } + __ blr(lr); + __ mov(rscratch1, r0); + __ pop_call_clobbered_registers(); + __ mov(r0, rscratch1); + + __ epilogue(); +} + +#undef __ + +#endif // COMPILER1 + +address ShenandoahBarrierSetAssembler::shenandoah_lrb() { + assert(_shenandoah_lrb != NULL, "need load reference barrier stub"); + return _shenandoah_lrb; +} + +#define __ cgen->assembler()-> + +// Shenandoah load reference barrier. +// +// Input: +// r0: OOP to evacuate. Not null. +// r1: load address +// +// Output: +// r0: Pointer to evacuated OOP. +// +// Trash rscratch1, rscratch2. Preserve everything else. +address ShenandoahBarrierSetAssembler::generate_shenandoah_lrb(StubCodeGenerator* cgen) { + + __ align(6); + StubCodeMark mark(cgen, "StubRoutines", "shenandoah_lrb"); + address start = __ pc(); + + Label work, done; + __ mov(rscratch2, ShenandoahHeap::in_cset_fast_test_addr()); + __ lsr(rscratch1, r0, ShenandoahHeapRegion::region_size_bytes_shift_jint()); + __ ldrb(rscratch2, Address(rscratch2, rscratch1)); + __ tbnz(rscratch2, 0, work); + __ ret(lr); + __ bind(work); + + Label slow_path; + __ ldr(rscratch1, Address(r0, oopDesc::mark_offset_in_bytes())); + __ eon(rscratch1, rscratch1, zr); + __ ands(zr, rscratch1, markOopDesc::lock_mask_in_place); + __ br(Assembler::NE, slow_path); + + // Decode forwarded object. + __ orr(rscratch1, rscratch1, markOopDesc::marked_value); + __ eon(r0, rscratch1, zr); + __ ret(lr); + + __ bind(slow_path); + __ enter(); // required for proper stackwalking of RuntimeStub frame + + __ push_call_clobbered_registers(); + + if (UseCompressedOops) { + __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_narrow)); + } else { + __ mov(lr, CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier)); + } + __ blr(lr); + __ mov(rscratch1, r0); + __ pop_call_clobbered_registers(); + __ mov(r0, rscratch1); + + __ leave(); // required for proper stackwalking of RuntimeStub frame + __ bind(done); + __ ret(lr); + + return start; +} + +#undef __ + +void ShenandoahBarrierSetAssembler::barrier_stubs_init() { + if (ShenandoahLoadRefBarrier) { + int stub_code_size = 2048; + ResourceMark rm; + BufferBlob* bb = BufferBlob::create("shenandoah_barrier_stubs", stub_code_size); + CodeBuffer buf(bb); + StubCodeGenerator cgen(&buf); + _shenandoah_lrb = generate_shenandoah_lrb(&cgen); + } +}