| /* |
| * Copyright (c) 2018, 2020, 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/shenandoahBarrierSet.hpp" |
| #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp" |
| #include "gc/shenandoah/shenandoahForwarding.hpp" |
| #include "gc/shenandoah/shenandoahHeap.hpp" |
| #include "gc/shenandoah/shenandoahHeapRegion.hpp" |
| #include "gc/shenandoah/shenandoahRuntime.hpp" |
| #include "gc/shenandoah/shenandoahThreadLocalData.hpp" |
| #include "gc/shenandoah/heuristics/shenandoahHeuristics.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) || ShenandoahIUBarrier || ShenandoahLoadRefBarrier) { |
| |
| Label done; |
| |
| // Avoid calling runtime if count == 0 |
| __ cbz(count, done); |
| |
| // Is GC active? |
| Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset())); |
| __ ldrb(rscratch1, gc_state); |
| if (ShenandoahSATBBarrier && 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) { |
| __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_narrow_oop_entry), src, dst, count); |
| } else { |
| __ call_VM_leaf(CAST_FROM_FN_PTR(address, ShenandoahRuntime::arraycopy_barrier_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, markOop::lock_mask_in_place); |
| __ br(Assembler::NE, done); |
| __ orr(tmp, tmp, markOop::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::iu_barrier(MacroAssembler* masm, Register dst, Register tmp) { |
| if (ShenandoahIUBarrier) { |
| __ push_call_clobbered_registers(); |
| satb_write_barrier_pre(masm, noreg, dst, rthread, tmp, true, false); |
| __ pop_call_clobbered_registers(); |
| } |
| } |
| |
| 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); |
| } |
| } |
| |
| // |
| // Arguments: |
| // |
| // Inputs: |
| // src: oop location to load from, might be clobbered |
| // |
| // Output: |
| // dst: oop loaded from src location |
| // |
| // Kill: |
| // rscratch1 (scratch reg) |
| // |
| // Alias: |
| // dst: rscratch1 (might use rscratch1 as temporary output register to avoid clobbering src) |
| // |
| 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(); |
| __ push_call_clobbered_registers(); |
| satb_write_barrier_pre(masm /* masm */, |
| noreg /* obj */, |
| dst /* pre_val */, |
| rthread /* thread */, |
| tmp1 /* tmp */, |
| true /* tosca_live */, |
| true /* expand_call */); |
| __ pop_call_clobbered_registers(); |
| __ 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 { |
| iu_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); |
| } |
| |
| // Special Shenandoah CAS implementation that handles false negatives due |
| // to concurrent evacuation. The service is more complex than a |
| // traditional CAS operation because the CAS operation is intended to |
| // succeed if the reference at addr exactly matches expected or if the |
| // reference at addr holds a pointer to a from-space object that has |
| // been relocated to the location named by expected. There are two |
| // races that must be addressed: |
| // a) A parallel thread may mutate the contents of addr so that it points |
| // to a different object. In this case, the CAS operation should fail. |
| // b) A parallel thread may heal the contents of addr, replacing a |
| // from-space pointer held in addr with the to-space pointer |
| // representing the new location of the object. |
| // Upon entry to cmpxchg_oop, it is assured that new_val equals NULL |
| // or it refers to an object that is not being evacuated out of |
| // from-space, or it refers to the to-space version of an object that |
| // is being evacuated out of from-space. |
| // |
| // By default the value held in the result register following execution |
| // of the generated code sequence is 0 to indicate failure of CAS, |
| // non-zero to indicate success. If is_cae, the result is the value most |
| // recently fetched from addr rather than a boolean success indicator. |
| // |
| // Clobbers rscratch1, rscratch2 |
| void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, |
| Register addr, |
| Register expected, |
| Register new_val, |
| bool acquire, bool release, |
| 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, tmp1, tmp2); |
| assert_different_registers(addr, new_val, tmp1, tmp2); |
| |
| Label step4, done; |
| |
| // There are two ways to reach this label. Initial entry into the |
| // cmpxchg_oop code expansion starts at step1 (which is equivalent |
| // to label step4). Additionally, in the rare case that four steps |
| // are required to perform the requested operation, the fourth step |
| // is the same as the first. On a second pass through step 1, |
| // control may flow through step 2 on its way to failure. It will |
| // not flow from step 2 to step 3 since we are assured that the |
| // memory at addr no longer holds a from-space pointer. |
| // |
| // The comments that immediately follow the step4 label apply only |
| // to the case in which control reaches this label by branch from |
| // step 3. |
| |
| __ bind (step4); |
| |
| // Step 4. CAS has failed because the value most recently fetched |
| // from addr is no longer the from-space pointer held in tmp2. If a |
| // different thread replaced the in-memory value with its equivalent |
| // to-space pointer, then CAS may still be able to succeed. The |
| // value held in the expected register has not changed. |
| // |
| // It is extremely rare we reach this point. For this reason, the |
| // implementation opts for smaller rather than potentially faster |
| // code. Ultimately, smaller code for this rare case most likely |
| // delivers higher overall throughput by enabling improved icache |
| // performance. |
| |
| // Step 1. Fast-path. |
| // |
| // Try to CAS with given arguments. If successful, then we are done. |
| // |
| // No label required for step 1. |
| |
| __ cmpxchg(addr, expected, new_val, size, acquire, release, false, tmp2); |
| // EQ flag set iff success. tmp2 holds value fetched. |
| |
| // If expected equals null but tmp2 does not equal null, the |
| // following branches to done to report failure of CAS. If both |
| // expected and tmp2 equal null, the following branches to done to |
| // report success of CAS. There's no need for a special test of |
| // expected equal to null. |
| |
| __ br(Assembler::EQ, done); |
| // if CAS failed, fall through to step 2 |
| |
| // Step 2. CAS has failed because the value held at addr does not |
| // match expected. This may be a false negative because the value fetched |
| // from addr (now held in tmp2) may be a from-space pointer to the |
| // original copy of same object referenced by to-space pointer expected. |
| // |
| // To resolve this, it suffices to find the forward pointer associated |
| // with fetched value. If this matches expected, retry CAS with new |
| // parameters. If this mismatches, then we have a legitimate |
| // failure, and we're done. |
| // |
| // No need for step2 label. |
| |
| // overwrite tmp1 with from-space pointer fetched from memory |
| __ mov(tmp1, tmp2); |
| |
| if (is_narrow) { |
| // Decode tmp1 in order to resolve its forward pointer |
| __ decode_heap_oop(tmp1, tmp1); |
| } |
| resolve_forward_pointer(masm, tmp1); |
| // Encode tmp1 to compare against expected. |
| __ encode_heap_oop(tmp1, tmp1); |
| |
| // Does forwarded value of fetched from-space pointer match original |
| // value of expected? If tmp1 holds null, this comparison will fail |
| // because we know from step1 that expected is not null. There is |
| // no need for a separate test for tmp1 (the value originally held |
| // in memory) equal to null. |
| __ cmp(tmp1, expected); |
| |
| // If not, then the failure was legitimate and we're done. |
| // Branching to done with NE condition denotes failure. |
| __ br(Assembler::NE, done); |
| |
| // Fall through to step 3. No need for step3 label. |
| |
| // Step 3. We've confirmed that the value originally held in memory |
| // (now held in tmp2) pointed to from-space version of original |
| // expected value. Try the CAS again with the from-space expected |
| // value. If it now succeeds, we're good. |
| // |
| // Note: tmp2 holds encoded from-space pointer that matches to-space |
| // object residing at expected. tmp2 is the new "expected". |
| |
| // Note that macro implementation of __cmpxchg cannot use same register |
| // tmp2 for result and expected since it overwrites result before it |
| // compares result with expected. |
| __ cmpxchg(addr, tmp2, new_val, size, acquire, release, false, noreg); |
| // EQ flag set iff success. tmp2 holds value fetched, tmp1 (rscratch1) clobbered. |
| |
| // If fetched value did not equal the new expected, this could |
| // still be a false negative because some other thread may have |
| // newly overwritten the memory value with its to-space equivalent. |
| __ br(Assembler::NE, step4); |
| |
| if (is_cae) { |
| // We're falling through to done to indicate success. Success |
| // with is_cae is denoted by returning the value of expected as |
| // result. |
| __ mov(tmp2, expected); |
| } |
| |
| __ bind(done); |
| // At entry to done, the Z (EQ) flag is on iff if the CAS |
| // operation was successful. Additionally, if is_cae, tmp2 holds |
| // the value most recently fetched from addr. In this case, success |
| // is denoted by tmp2 matching expected. |
| |
| if (is_cae) { |
| __ mov(result, tmp2); |
| } 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, markOop::lock_mask_in_place); |
| __ br(Assembler::NE, slow_path); |
| |
| // Decode forwarded object. |
| __ orr(tmp1, tmp1, markOop::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); |
| __ tbz(tmp, ShenandoahHeap::MARKING_BITPOS, 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 slow_path; |
| __ 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, slow_path); |
| __ 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 |
| __ 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); |
| } |
| } |