| /* |
| * 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 "ci/ciUtilities.hpp" |
| #include "gc/shared/cardTable.hpp" |
| #include "gc/shared/cardTableBarrierSet.hpp" |
| #include "gc/shared/c2/cardTableBarrierSetC2.hpp" |
| #include "opto/arraycopynode.hpp" |
| #include "opto/graphKit.hpp" |
| #include "opto/idealKit.hpp" |
| #include "opto/macro.hpp" |
| #include "utilities/macros.hpp" |
| |
| #define __ ideal. |
| |
| Node* CardTableBarrierSetC2::byte_map_base_node(GraphKit* kit) const { |
| // Get base of card map |
| jbyte* card_table_base = ci_card_table_address(); |
| if (card_table_base != NULL) { |
| return kit->makecon(TypeRawPtr::make((address)card_table_base)); |
| } else { |
| return kit->null(); |
| } |
| } |
| |
| // vanilla/CMS post barrier |
| // Insert a write-barrier store. This is to let generational GC work; we have |
| // to flag all oop-stores before the next GC point. |
| void CardTableBarrierSetC2::post_barrier(GraphKit* kit, |
| Node* ctl, |
| Node* oop_store, |
| Node* obj, |
| Node* adr, |
| uint adr_idx, |
| Node* val, |
| BasicType bt, |
| bool use_precise) const { |
| CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(BarrierSet::barrier_set()); |
| CardTable* ct = ctbs->card_table(); |
| // No store check needed if we're storing a NULL or an old object |
| // (latter case is probably a string constant). The concurrent |
| // mark sweep garbage collector, however, needs to have all nonNull |
| // oop updates flagged via card-marks. |
| if (val != NULL && val->is_Con()) { |
| // must be either an oop or NULL |
| const Type* t = val->bottom_type(); |
| if (t == TypePtr::NULL_PTR || t == Type::TOP) |
| // stores of null never (?) need barriers |
| 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_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); |
| |
| // Convert the pointer to an int prior to doing math on it |
| Node* cast = __ CastPX(__ ctrl(), adr); |
| |
| // Divide by card size |
| Node* card_offset = __ URShiftX( cast, __ ConI(CardTable::card_shift) ); |
| |
| // Combine card table base and card offset |
| Node* card_adr = __ AddP(__ top(), byte_map_base_node(kit), card_offset ); |
| |
| // Get the alias_index for raw card-mark memory |
| int adr_type = Compile::AliasIdxRaw; |
| Node* zero = __ ConI(0); // Dirty card value |
| |
| if (UseCondCardMark) { |
| if (ct->scanned_concurrently()) { |
| kit->insert_mem_bar(Op_MemBarVolatile, oop_store); |
| __ sync_kit(kit); |
| } |
| // The classic GC reference write barrier is typically implemented |
| // as a store into the global card mark table. Unfortunately |
| // unconditional stores can result in false sharing and excessive |
| // coherence traffic as well as false transactional aborts. |
| // UseCondCardMark enables MP "polite" conditional card mark |
| // stores. In theory we could relax the load from ctrl() to |
| // no_ctrl, but that doesn't buy much latitude. |
| Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, T_BYTE, adr_type); |
| __ if_then(card_val, BoolTest::ne, zero); |
| } |
| |
| // Smash zero into card |
| if(!ct->scanned_concurrently()) { |
| __ store(__ ctrl(), card_adr, zero, T_BYTE, adr_type, MemNode::unordered); |
| } else { |
| // Specialized path for CM store barrier |
| __ storeCM(__ ctrl(), card_adr, zero, oop_store, adr_idx, T_BYTE, adr_type); |
| } |
| |
| if (UseCondCardMark) { |
| __ end_if(); |
| } |
| |
| // Final sync IdealKit and GraphKit. |
| kit->final_sync(ideal); |
| } |
| |
| void CardTableBarrierSetC2::clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const { |
| BarrierSetC2::clone(kit, src, dst, size, is_array); |
| const TypePtr* raw_adr_type = TypeRawPtr::BOTTOM; |
| |
| // If necessary, emit some card marks afterwards. (Non-arrays only.) |
| bool card_mark = !is_array && !use_ReduceInitialCardMarks(); |
| if (card_mark) { |
| assert(!is_array, ""); |
| // Put in store barrier for any and all oops we are sticking |
| // into this object. (We could avoid this if we could prove |
| // that the object type contains no oop fields at all.) |
| Node* no_particular_value = NULL; |
| Node* no_particular_field = NULL; |
| int raw_adr_idx = Compile::AliasIdxRaw; |
| post_barrier(kit, kit->control(), |
| kit->memory(raw_adr_type), |
| dst, |
| no_particular_field, |
| raw_adr_idx, |
| no_particular_value, |
| T_OBJECT, |
| false); |
| } |
| } |
| |
| bool CardTableBarrierSetC2::use_ReduceInitialCardMarks() const { |
| return ReduceInitialCardMarks; |
| } |
| |
| bool CardTableBarrierSetC2::is_gc_barrier_node(Node* node) const { |
| return ModRefBarrierSetC2::is_gc_barrier_node(node) || node->Opcode() == Op_StoreCM; |
| } |
| |
| void CardTableBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { |
| assert(node->Opcode() == Op_CastP2X, "ConvP2XNode required"); |
| Node *shift = node->unique_out(); |
| Node *addp = shift->unique_out(); |
| for (DUIterator_Last jmin, j = addp->last_outs(jmin); j >= jmin; --j) { |
| Node *mem = addp->last_out(j); |
| if (UseCondCardMark && mem->is_Load()) { |
| assert(mem->Opcode() == Op_LoadB, "unexpected code shape"); |
| // The load is checking if the card has been written so |
| // replace it with zero to fold the test. |
| macro->replace_node(mem, macro->intcon(0)); |
| continue; |
| } |
| assert(mem->is_Store(), "store required"); |
| macro->replace_node(mem, mem->in(MemNode::Memory)); |
| } |
| } |
| |
| bool CardTableBarrierSetC2::array_copy_requires_gc_barriers(BasicType type) const { |
| return !use_ReduceInitialCardMarks(); |
| } |
