| /* |
| * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * 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/g1/c2/g1BarrierSetC2.hpp" |
| #include "gc/g1/g1BarrierSet.hpp" |
| #include "gc/g1/g1BarrierSetRuntime.hpp" |
| #include "gc/g1/g1CardTable.hpp" |
| #include "gc/g1/g1ThreadLocalData.hpp" |
| #include "gc/g1/heapRegion.hpp" |
| #include "opto/arraycopynode.hpp" |
| #include "opto/graphKit.hpp" |
| #include "opto/idealKit.hpp" |
| #include "opto/macro.hpp" |
| #include "opto/type.hpp" |
| #include "utilities/macros.hpp" |
| |
| const TypeFunc *G1BarrierSetC2::write_ref_field_pre_entry_Type() { |
| const Type **fields = TypeTuple::fields(2); |
| fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value |
| fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread |
| const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields); |
| |
| // create result type (range) |
| fields = TypeTuple::fields(0); |
| const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+0, fields); |
| |
| return TypeFunc::make(domain, range); |
| } |
| |
| const TypeFunc *G1BarrierSetC2::write_ref_field_post_entry_Type() { |
| const Type **fields = TypeTuple::fields(2); |
| fields[TypeFunc::Parms+0] = TypeRawPtr::NOTNULL; // Card addr |
| fields[TypeFunc::Parms+1] = TypeRawPtr::NOTNULL; // thread |
| const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields); |
| |
| // create result type (range) |
| fields = TypeTuple::fields(0); |
| const TypeTuple *range = TypeTuple::make(TypeFunc::Parms, fields); |
| |
| return TypeFunc::make(domain, range); |
| } |
| |
| #define __ ideal. |
| /* |
| * Determine if the G1 pre-barrier can be removed. The pre-barrier is |
| * required by SATB to make sure all objects live at the start of the |
| * marking are kept alive, all reference updates need to any previous |
| * reference stored before writing. |
| * |
| * If the previous value is NULL there is no need to save the old value. |
| * References that are NULL are filtered during runtime by the barrier |
| * code to avoid unnecessary queuing. |
| * |
| * However in the case of newly allocated objects it might be possible to |
| * prove that the reference about to be overwritten is NULL during compile |
| * time and avoid adding the barrier code completely. |
| * |
| * The compiler needs to determine that the object in which a field is about |
| * to be written is newly allocated, and that no prior store to the same field |
| * has happened since the allocation. |
| * |
| * Returns true if the pre-barrier can be removed |
| */ |
| bool G1BarrierSetC2::g1_can_remove_pre_barrier(GraphKit* kit, |
| PhaseTransform* phase, |
| Node* adr, |
| BasicType bt, |
| uint adr_idx) const { |
| intptr_t offset = 0; |
| Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset); |
| AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase); |
| |
| if (offset == Type::OffsetBot) { |
| return false; // cannot unalias unless there are precise offsets |
| } |
| |
| if (alloc == NULL) { |
| return false; // No allocation found |
| } |
| |
| intptr_t size_in_bytes = type2aelembytes(bt); |
| |
| Node* mem = kit->memory(adr_idx); // start searching here... |
| |
| for (int cnt = 0; cnt < 50; cnt++) { |
| |
| if (mem->is_Store()) { |
| |
| Node* st_adr = mem->in(MemNode::Address); |
| intptr_t st_offset = 0; |
| Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset); |
| |
| if (st_base == NULL) { |
| break; // inscrutable pointer |
| } |
| |
| // Break we have found a store with same base and offset as ours so break |
| if (st_base == base && st_offset == offset) { |
| break; |
| } |
| |
| if (st_offset != offset && st_offset != Type::OffsetBot) { |
| const int MAX_STORE = BytesPerLong; |
| if (st_offset >= offset + size_in_bytes || |
| st_offset <= offset - MAX_STORE || |
| st_offset <= offset - mem->as_Store()->memory_size()) { |
| // Success: The offsets are provably independent. |
| // (You may ask, why not just test st_offset != offset and be done? |
| // The answer is that stores of different sizes can co-exist |
| // in the same sequence of RawMem effects. We sometimes initialize |
| // a whole 'tile' of array elements with a single jint or jlong.) |
| mem = mem->in(MemNode::Memory); |
| continue; // advance through independent store memory |
| } |
| } |
| |
| if (st_base != base |
| && MemNode::detect_ptr_independence(base, alloc, st_base, |
| AllocateNode::Ideal_allocation(st_base, phase), |
| phase)) { |
| // Success: The bases are provably independent. |
| mem = mem->in(MemNode::Memory); |
| continue; // advance through independent store memory |
| } |
| } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) { |
| |
| InitializeNode* st_init = mem->in(0)->as_Initialize(); |
| AllocateNode* st_alloc = st_init->allocation(); |
| |
| // Make sure that we are looking at the same allocation site. |
| // The alloc variable is guaranteed to not be null here from earlier check. |
| if (alloc == st_alloc) { |
| // Check that the initialization is storing NULL so that no previous store |
| // has been moved up and directly write a reference |
| Node* captured_store = st_init->find_captured_store(offset, |
| type2aelembytes(T_OBJECT), |
| phase); |
| if (captured_store == NULL || captured_store == st_init->zero_memory()) { |
| return true; |
| } |
| } |
| } |
| |
| // Unless there is an explicit 'continue', we must bail out here, |
| // because 'mem' is an inscrutable memory state (e.g., a call). |
| break; |
| } |
| |
| return false; |
| } |
| |
| // G1 pre/post barriers |
| void G1BarrierSetC2::pre_barrier(GraphKit* kit, |
| bool do_load, |
| Node* ctl, |
| Node* obj, |
| Node* adr, |
| uint alias_idx, |
| Node* val, |
| const TypeOopPtr* val_type, |
| Node* pre_val, |
| BasicType bt) const { |
| // Some sanity checks |
| // Note: val is unused in this routine. |
| |
| if (do_load) { |
| // We need to generate the load of the previous value |
| assert(obj != NULL, "must have a base"); |
| assert(adr != NULL, "where are loading from?"); |
| assert(pre_val == NULL, "loaded already?"); |
| assert(val_type != NULL, "need a type"); |
| |
| if (use_ReduceInitialCardMarks() |
| && g1_can_remove_pre_barrier(kit, &kit->gvn(), adr, bt, alias_idx)) { |
| return; |
| } |
| |
| } else { |
| // In this case both val_type and alias_idx are unused. |
| assert(pre_val != NULL, "must be loaded already"); |
| // Nothing to be done if pre_val is null. |
| if (pre_val->bottom_type() == TypePtr::NULL_PTR) return; |
| assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here"); |
| } |
| assert(bt == T_OBJECT, "or we shouldn't be here"); |
| |
| IdealKit ideal(kit, true); |
| |
| Node* tls = __ thread(); // ThreadLocalStorage |
| |
| Node* no_base = __ top(); |
| Node* zero = __ ConI(0); |
| Node* zeroX = __ ConX(0); |
| |
| float likely = PROB_LIKELY(0.999); |
| float unlikely = PROB_UNLIKELY(0.999); |
| |
| BasicType active_type = in_bytes(SATBMarkQueue::byte_width_of_active()) == 4 ? T_INT : T_BYTE; |
| assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 4 || in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "flag width"); |
| |
| // Offsets into the thread |
| const int marking_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()); |
| const int index_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset()); |
| const int buffer_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset()); |
| |
| // Now the actual pointers into the thread |
| Node* marking_adr = __ AddP(no_base, tls, __ ConX(marking_offset)); |
| Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset)); |
| Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset)); |
| |
| // Now some of the values |
| Node* marking = __ load(__ ctrl(), marking_adr, TypeInt::INT, active_type, Compile::AliasIdxRaw); |
| |
| // if (!marking) |
| __ if_then(marking, BoolTest::ne, zero, unlikely); { |
| BasicType index_bt = TypeX_X->basic_type(); |
| assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 SATBMarkQueue::_index with wrong size."); |
| Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw); |
| |
| if (do_load) { |
| // load original value |
| // alias_idx correct?? |
| pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx); |
| } |
| |
| // if (pre_val != NULL) |
| __ if_then(pre_val, BoolTest::ne, kit->null()); { |
| Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw); |
| |
| // is the queue for this thread full? |
| __ if_then(index, BoolTest::ne, zeroX, likely); { |
| |
| // decrement the index |
| Node* next_index = kit->gvn().transform(new SubXNode(index, __ ConX(sizeof(intptr_t)))); |
| |
| // Now get the buffer location we will log the previous value into and store it |
| Node *log_addr = __ AddP(no_base, buffer, next_index); |
| __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered); |
| // update the index |
| __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered); |
| |
| } __ else_(); { |
| |
| // logging buffer is full, call the runtime |
| const TypeFunc *tf = write_ref_field_pre_entry_Type(); |
| __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_pre_entry), "write_ref_field_pre_entry", pre_val, tls); |
| } __ end_if(); // (!index) |
| } __ end_if(); // (pre_val != NULL) |
| } __ end_if(); // (!marking) |
| |
| // Final sync IdealKit and GraphKit. |
| kit->final_sync(ideal); |
| } |
| |
| /* |
| * G1 similar to any GC with a Young Generation requires a way to keep track of |
| * references from Old Generation to Young Generation to make sure all live |
| * objects are found. G1 also requires to keep track of object references |
| * between different regions to enable evacuation of old regions, which is done |
| * as part of mixed collections. References are tracked in remembered sets and |
| * is continuously updated as reference are written to with the help of the |
| * post-barrier. |
| * |
| * To reduce the number of updates to the remembered set the post-barrier |
| * filters updates to fields in objects located in the Young Generation, |
| * the same region as the reference, when the NULL is being written or |
| * if the card is already marked as dirty by an earlier write. |
| * |
| * Under certain circumstances it is possible to avoid generating the |
| * post-barrier completely if it is possible during compile time to prove |
| * the object is newly allocated and that no safepoint exists between the |
| * allocation and the store. |
| * |
| * In the case of slow allocation the allocation code must handle the barrier |
| * as part of the allocation in the case the allocated object is not located |
| * in the nursery, this would happen for humongous objects. This is similar to |
| * how CMS is required to handle this case, see the comments for the method |
| * CollectedHeap::new_deferred_store_barrier and OptoRuntime::new_deferred_store_barrier. |
| * A deferred card mark is required for these objects and handled in the above |
| * mentioned methods. |
| * |
| * Returns true if the post barrier can be removed |
| */ |
| bool G1BarrierSetC2::g1_can_remove_post_barrier(GraphKit* kit, |
| PhaseTransform* phase, Node* store, |
| Node* adr) const { |
| intptr_t offset = 0; |
| Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset); |
| AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase); |
| |
| if (offset == Type::OffsetBot) { |
| return false; // cannot unalias unless there are precise offsets |
| } |
| |
| if (alloc == NULL) { |
| return false; // No allocation found |
| } |
| |
| // Start search from Store node |
| Node* mem = store->in(MemNode::Control); |
| if (mem->is_Proj() && mem->in(0)->is_Initialize()) { |
| |
| InitializeNode* st_init = mem->in(0)->as_Initialize(); |
| AllocateNode* st_alloc = st_init->allocation(); |
| |
| // Make sure we are looking at the same allocation |
| if (alloc == st_alloc) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| // |
| // Update the card table and add card address to the queue |
| // |
| void G1BarrierSetC2::g1_mark_card(GraphKit* kit, |
| IdealKit& ideal, |
| Node* card_adr, |
| Node* oop_store, |
| uint oop_alias_idx, |
| Node* index, |
| Node* index_adr, |
| Node* buffer, |
| const TypeFunc* tf) const { |
| Node* zero = __ ConI(0); |
| Node* zeroX = __ ConX(0); |
| Node* no_base = __ top(); |
| BasicType card_bt = T_BYTE; |
| // Smash zero into card. MUST BE ORDERED WRT TO STORE |
| __ storeCM(__ ctrl(), card_adr, zero, oop_store, oop_alias_idx, card_bt, Compile::AliasIdxRaw); |
| |
| // Now do the queue work |
| __ if_then(index, BoolTest::ne, zeroX); { |
| |
| Node* next_index = kit->gvn().transform(new SubXNode(index, __ ConX(sizeof(intptr_t)))); |
| Node* log_addr = __ AddP(no_base, buffer, next_index); |
| |
| // Order, see storeCM. |
| __ store(__ ctrl(), log_addr, card_adr, T_ADDRESS, Compile::AliasIdxRaw, MemNode::unordered); |
| __ store(__ ctrl(), index_adr, next_index, TypeX_X->basic_type(), Compile::AliasIdxRaw, MemNode::unordered); |
| |
| } __ else_(); { |
| __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry), "write_ref_field_post_entry", card_adr, __ thread()); |
| } __ end_if(); |
| |
| } |
| |
| void G1BarrierSetC2::post_barrier(GraphKit* kit, |
| Node* ctl, |
| Node* oop_store, |
| Node* obj, |
| Node* adr, |
| uint alias_idx, |
| Node* val, |
| BasicType bt, |
| bool use_precise) const { |
| // If we are writing a NULL then we need no post barrier |
| |
| if (val != NULL && val->is_Con() && val->bottom_type() == TypePtr::NULL_PTR) { |
| // Must be NULL |
| const Type* t = val->bottom_type(); |
| assert(t == Type::TOP || t == TypePtr::NULL_PTR, "must be NULL"); |
| // No post barrier if writing NULLx |
| return; |
| } |
| |
| if (use_ReduceInitialCardMarks() && obj == kit->just_allocated_object(kit->control())) { |
| // We can skip marks on a freshly-allocated object in Eden. |
| // Keep this code in sync with new_deferred_store_barrier() in runtime.cpp. |
| // That routine informs GC to take appropriate compensating steps, |
| // upon a slow-path allocation, so as to make this card-mark |
| // elision safe. |
| return; |
| } |
| |
| if (use_ReduceInitialCardMarks() |
| && g1_can_remove_post_barrier(kit, &kit->gvn(), oop_store, adr)) { |
| return; |
| } |
| |
| if (!use_precise) { |
| // All card marks for a (non-array) instance are in one place: |
| adr = obj; |
| } |
| // (Else it's an array (or unknown), and we want more precise card marks.) |
| assert(adr != NULL, ""); |
| |
| IdealKit ideal(kit, true); |
| |
| Node* tls = __ thread(); // ThreadLocalStorage |
| |
| Node* no_base = __ top(); |
| float unlikely = PROB_UNLIKELY(0.999); |
| Node* young_card = __ ConI((jint)G1CardTable::g1_young_card_val()); |
| Node* dirty_card = __ ConI((jint)G1CardTable::dirty_card_val()); |
| Node* zeroX = __ ConX(0); |
| |
| const TypeFunc *tf = write_ref_field_post_entry_Type(); |
| |
| // Offsets into the thread |
| const int index_offset = in_bytes(G1ThreadLocalData::dirty_card_queue_index_offset()); |
| const int buffer_offset = in_bytes(G1ThreadLocalData::dirty_card_queue_buffer_offset()); |
| |
| // Pointers into the thread |
| |
| Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset)); |
| Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset)); |
| |
| // Now some values |
| // Use ctrl to avoid hoisting these values past a safepoint, which could |
| // potentially reset these fields in the JavaThread. |
| Node* index = __ load(__ ctrl(), index_adr, TypeX_X, TypeX_X->basic_type(), Compile::AliasIdxRaw); |
| Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw); |
| |
| // Convert the store obj pointer to an int prior to doing math on it |
| // Must use ctrl to prevent "integerized oop" existing across safepoint |
| Node* cast = __ CastPX(__ ctrl(), adr); |
| |
| // Divide pointer by card size |
| Node* card_offset = __ URShiftX( cast, __ ConI(CardTable::card_shift) ); |
| |
| // Combine card table base and card offset |
| Node* card_adr = __ AddP(no_base, byte_map_base_node(kit), card_offset ); |
| |
| // If we know the value being stored does it cross regions? |
| |
| if (val != NULL) { |
| // Does the store cause us to cross regions? |
| |
| // Should be able to do an unsigned compare of region_size instead of |
| // and extra shift. Do we have an unsigned compare?? |
| // Node* region_size = __ ConI(1 << HeapRegion::LogOfHRGrainBytes); |
| Node* xor_res = __ URShiftX ( __ XorX( cast, __ CastPX(__ ctrl(), val)), __ ConI(HeapRegion::LogOfHRGrainBytes)); |
| |
| // if (xor_res == 0) same region so skip |
| __ if_then(xor_res, BoolTest::ne, zeroX); { |
| |
| // No barrier if we are storing a NULL |
| __ if_then(val, BoolTest::ne, kit->null(), unlikely); { |
| |
| // Ok must mark the card if not already dirty |
| |
| // load the original value of the card |
| Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw); |
| |
| __ if_then(card_val, BoolTest::ne, young_card); { |
| kit->sync_kit(ideal); |
| kit->insert_mem_bar(Op_MemBarVolatile, oop_store); |
| __ sync_kit(kit); |
| |
| Node* card_val_reload = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw); |
| __ if_then(card_val_reload, BoolTest::ne, dirty_card); { |
| g1_mark_card(kit, ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf); |
| } __ end_if(); |
| } __ end_if(); |
| } __ end_if(); |
| } __ end_if(); |
| } else { |
| // The Object.clone() intrinsic uses this path if !ReduceInitialCardMarks. |
| // We don't need a barrier here if the destination is a newly allocated object |
| // in Eden. Otherwise, GC verification breaks because we assume that cards in Eden |
| // are set to 'g1_young_gen' (see G1CardTable::verify_g1_young_region()). |
| assert(!use_ReduceInitialCardMarks(), "can only happen with card marking"); |
| Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw); |
| __ if_then(card_val, BoolTest::ne, young_card); { |
| g1_mark_card(kit, ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf); |
| } __ end_if(); |
| } |
| |
| // Final sync IdealKit and GraphKit. |
| kit->final_sync(ideal); |
| } |
| |
| // Helper that guards and inserts a pre-barrier. |
| void G1BarrierSetC2::insert_pre_barrier(GraphKit* kit, Node* base_oop, Node* offset, |
| Node* pre_val, bool need_mem_bar) const { |
| // We could be accessing the referent field of a reference object. If so, when G1 |
| // is enabled, we need to log the value in the referent field in an SATB buffer. |
| // This routine performs some compile time filters and generates suitable |
| // runtime filters that guard the pre-barrier code. |
| // Also add memory barrier for non volatile load from the referent field |
| // to prevent commoning of loads across safepoint. |
| |
| // Some compile time checks. |
| |
| // If offset is a constant, is it java_lang_ref_Reference::_reference_offset? |
| const TypeX* otype = offset->find_intptr_t_type(); |
| if (otype != NULL && otype->is_con() && |
| otype->get_con() != java_lang_ref_Reference::referent_offset) { |
| // Constant offset but not the reference_offset so just return |
| return; |
| } |
| |
| // We only need to generate the runtime guards for instances. |
| const TypeOopPtr* btype = base_oop->bottom_type()->isa_oopptr(); |
| if (btype != NULL) { |
| if (btype->isa_aryptr()) { |
| // Array type so nothing to do |
| return; |
| } |
| |
| const TypeInstPtr* itype = btype->isa_instptr(); |
| if (itype != NULL) { |
| // Can the klass of base_oop be statically determined to be |
| // _not_ a sub-class of Reference and _not_ Object? |
| ciKlass* klass = itype->klass(); |
| if ( klass->is_loaded() && |
| !klass->is_subtype_of(kit->env()->Reference_klass()) && |
| !kit->env()->Object_klass()->is_subtype_of(klass)) { |
| return; |
| } |
| } |
| } |
| |
| // The compile time filters did not reject base_oop/offset so |
| // we need to generate the following runtime filters |
| // |
| // if (offset == java_lang_ref_Reference::_reference_offset) { |
| // if (instance_of(base, java.lang.ref.Reference)) { |
| // pre_barrier(_, pre_val, ...); |
| // } |
| // } |
| |
| float likely = PROB_LIKELY( 0.999); |
| float unlikely = PROB_UNLIKELY(0.999); |
| |
| IdealKit ideal(kit); |
| |
| Node* referent_off = __ ConX(java_lang_ref_Reference::referent_offset); |
| |
| __ if_then(offset, BoolTest::eq, referent_off, unlikely); { |
| // Update graphKit memory and control from IdealKit. |
| kit->sync_kit(ideal); |
| |
| Node* ref_klass_con = kit->makecon(TypeKlassPtr::make(kit->env()->Reference_klass())); |
| Node* is_instof = kit->gen_instanceof(base_oop, ref_klass_con); |
| |
| // Update IdealKit memory and control from graphKit. |
| __ sync_kit(kit); |
| |
| Node* one = __ ConI(1); |
| // is_instof == 0 if base_oop == NULL |
| __ if_then(is_instof, BoolTest::eq, one, unlikely); { |
| |
| // Update graphKit from IdeakKit. |
| kit->sync_kit(ideal); |
| |
| // Use the pre-barrier to record the value in the referent field |
| pre_barrier(kit, false /* do_load */, |
| __ ctrl(), |
| NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */, |
| pre_val /* pre_val */, |
| T_OBJECT); |
| if (need_mem_bar) { |
| // Add memory barrier to prevent commoning reads from this field |
| // across safepoint since GC can change its value. |
| kit->insert_mem_bar(Op_MemBarCPUOrder); |
| } |
| // Update IdealKit from graphKit. |
| __ sync_kit(kit); |
| |
| } __ end_if(); // _ref_type != ref_none |
| } __ end_if(); // offset == referent_offset |
| |
| // Final sync IdealKit and GraphKit. |
| kit->final_sync(ideal); |
| } |
| |
| #undef __ |
| |
| Node* G1BarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const { |
| DecoratorSet decorators = access.decorators(); |
| GraphKit* kit = access.kit(); |
| |
| Node* adr = access.addr().node(); |
| Node* obj = access.base(); |
| |
| bool mismatched = (decorators & C2_MISMATCHED) != 0; |
| bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0; |
| bool in_heap = (decorators & IN_HEAP) != 0; |
| bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0; |
| bool is_unordered = (decorators & MO_UNORDERED) != 0; |
| bool need_cpu_mem_bar = !is_unordered || mismatched || !in_heap; |
| |
| Node* offset = adr->is_AddP() ? adr->in(AddPNode::Offset) : kit->top(); |
| Node* load = CardTableBarrierSetC2::load_at_resolved(access, val_type); |
| |
| // If we are reading the value of the referent field of a Reference |
| // object (either by using Unsafe directly or through reflection) |
| // then, if G1 is enabled, we need to record the referent in an |
| // SATB log buffer using the pre-barrier mechanism. |
| // Also we need to add memory barrier to prevent commoning reads |
| // from this field across safepoint since GC can change its value. |
| bool need_read_barrier = in_heap && (on_weak || |
| (unknown && offset != kit->top() && obj != kit->top())); |
| |
| if (!access.is_oop() || !need_read_barrier) { |
| return load; |
| } |
| |
| if (on_weak) { |
| // Use the pre-barrier to record the value in the referent field |
| pre_barrier(kit, false /* do_load */, |
| kit->control(), |
| NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */, |
| load /* pre_val */, T_OBJECT); |
| // Add memory barrier to prevent commoning reads from this field |
| // across safepoint since GC can change its value. |
| kit->insert_mem_bar(Op_MemBarCPUOrder); |
| } else if (unknown) { |
| // We do not require a mem bar inside pre_barrier if need_mem_bar |
| // is set: the barriers would be emitted by us. |
| insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar); |
| } |
| |
| return load; |
| } |
| |
| bool G1BarrierSetC2::is_gc_barrier_node(Node* node) const { |
| if (CardTableBarrierSetC2::is_gc_barrier_node(node)) { |
| return true; |
| } |
| if (node->Opcode() != Op_CallLeaf) { |
| return false; |
| } |
| CallLeafNode *call = node->as_CallLeaf(); |
| if (call->_name == NULL) { |
| return false; |
| } |
| |
| return strcmp(call->_name, "write_ref_field_pre_entry") == 0 || strcmp(call->_name, "write_ref_field_post_entry") == 0; |
| } |
| |
| void G1BarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { |
| assert(node->Opcode() == Op_CastP2X, "ConvP2XNode required"); |
| assert(node->outcnt() <= 2, "expects 1 or 2 users: Xor and URShift nodes"); |
| // It could be only one user, URShift node, in Object.clone() intrinsic |
| // but the new allocation is passed to arraycopy stub and it could not |
| // be scalar replaced. So we don't check the case. |
| |
| // An other case of only one user (Xor) is when the value check for NULL |
| // in G1 post barrier is folded after CCP so the code which used URShift |
| // is removed. |
| |
| // Take Region node before eliminating post barrier since it also |
| // eliminates CastP2X node when it has only one user. |
| Node* this_region = node->in(0); |
| assert(this_region != NULL, ""); |
| |
| // Remove G1 post barrier. |
| |
| // Search for CastP2X->Xor->URShift->Cmp path which |
| // checks if the store done to a different from the value's region. |
| // And replace Cmp with #0 (false) to collapse G1 post barrier. |
| Node* xorx = node->find_out_with(Op_XorX); |
| if (xorx != NULL) { |
| Node* shift = xorx->unique_out(); |
| Node* cmpx = shift->unique_out(); |
| assert(cmpx->is_Cmp() && cmpx->unique_out()->is_Bool() && |
| cmpx->unique_out()->as_Bool()->_test._test == BoolTest::ne, |
| "missing region check in G1 post barrier"); |
| macro->replace_node(cmpx, macro->makecon(TypeInt::CC_EQ)); |
| |
| // Remove G1 pre barrier. |
| |
| // Search "if (marking != 0)" check and set it to "false". |
| // There is no G1 pre barrier if previous stored value is NULL |
| // (for example, after initialization). |
| if (this_region->is_Region() && this_region->req() == 3) { |
| int ind = 1; |
| if (!this_region->in(ind)->is_IfFalse()) { |
| ind = 2; |
| } |
| if (this_region->in(ind)->is_IfFalse() && |
| this_region->in(ind)->in(0)->Opcode() == Op_If) { |
| Node* bol = this_region->in(ind)->in(0)->in(1); |
| assert(bol->is_Bool(), ""); |
| cmpx = bol->in(1); |
| if (bol->as_Bool()->_test._test == BoolTest::ne && |
| cmpx->is_Cmp() && cmpx->in(2) == macro->intcon(0) && |
| cmpx->in(1)->is_Load()) { |
| Node* adr = cmpx->in(1)->as_Load()->in(MemNode::Address); |
| const int marking_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()); |
| if (adr->is_AddP() && adr->in(AddPNode::Base) == macro->top() && |
| adr->in(AddPNode::Address)->Opcode() == Op_ThreadLocal && |
| adr->in(AddPNode::Offset) == macro->MakeConX(marking_offset)) { |
| macro->replace_node(cmpx, macro->makecon(TypeInt::CC_EQ)); |
| } |
| } |
| } |
| } |
| } else { |
| assert(!use_ReduceInitialCardMarks(), "can only happen with card marking"); |
| // This is a G1 post barrier emitted by the Object.clone() intrinsic. |
| // Search for the CastP2X->URShiftX->AddP->LoadB->Cmp path which checks if the card |
| // is marked as young_gen and replace the Cmp with 0 (false) to collapse the barrier. |
| Node* shift = node->find_out_with(Op_URShiftX); |
| assert(shift != NULL, "missing G1 post barrier"); |
| Node* addp = shift->unique_out(); |
| Node* load = addp->find_out_with(Op_LoadB); |
| assert(load != NULL, "missing G1 post barrier"); |
| Node* cmpx = load->unique_out(); |
| assert(cmpx->is_Cmp() && cmpx->unique_out()->is_Bool() && |
| cmpx->unique_out()->as_Bool()->_test._test == BoolTest::ne, |
| "missing card value check in G1 post barrier"); |
| macro->replace_node(cmpx, macro->makecon(TypeInt::CC_EQ)); |
| // There is no G1 pre barrier in this case |
| } |
| // Now CastP2X can be removed since it is used only on dead path |
| // which currently still alive until igvn optimize it. |
| assert(node->outcnt() == 0 || node->unique_out()->Opcode() == Op_URShiftX, ""); |
| macro->replace_node(node, macro->top()); |
| } |
| |
| Node* G1BarrierSetC2::step_over_gc_barrier(Node* c) const { |
| if (!use_ReduceInitialCardMarks() && |
| c != NULL && c->is_Region() && c->req() == 3) { |
| for (uint i = 1; i < c->req(); i++) { |
| if (c->in(i) != NULL && c->in(i)->is_Region() && |
| c->in(i)->req() == 3) { |
| Node* r = c->in(i); |
| for (uint j = 1; j < r->req(); j++) { |
| if (r->in(j) != NULL && r->in(j)->is_Proj() && |
| r->in(j)->in(0) != NULL && |
| r->in(j)->in(0)->Opcode() == Op_CallLeaf && |
| r->in(j)->in(0)->as_Call()->entry_point() == CAST_FROM_FN_PTR(address, G1BarrierSetRuntime::write_ref_field_post_entry)) { |
| Node* call = r->in(j)->in(0); |
| c = c->in(i == 1 ? 2 : 1); |
| if (c != NULL && c->Opcode() != Op_Parm) { |
| c = c->in(0); |
| if (c != NULL) { |
| c = c->in(0); |
| assert(call->in(0) == NULL || |
| call->in(0)->in(0) == NULL || |
| call->in(0)->in(0)->in(0) == NULL || |
| call->in(0)->in(0)->in(0)->in(0) == NULL || |
| call->in(0)->in(0)->in(0)->in(0)->in(0) == NULL || |
| c == call->in(0)->in(0)->in(0)->in(0)->in(0), "bad barrier shape"); |
| return c; |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| return c; |
| } |
