1 /* 2 * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_SHARED_C2_BARRIERSETC2_HPP 26 #define SHARE_GC_SHARED_C2_BARRIERSETC2_HPP 27 28 #include "memory/allocation.hpp" 29 #include "oops/accessDecorators.hpp" 30 #include "opto/loopnode.hpp" 31 #include "opto/matcher.hpp" 32 #include "opto/memnode.hpp" 33 #include "utilities/globalDefinitions.hpp" 34 35 // This means the access is mismatched. This means the value of an access 36 // is not equivalent to the value pointed to by the address. 37 const DecoratorSet C2_MISMATCHED = DECORATOR_LAST << 1; 38 // The access may not be aligned to its natural size. 39 const DecoratorSet C2_UNALIGNED = DECORATOR_LAST << 2; 40 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed, 41 // but never false positives. 42 const DecoratorSet C2_WEAK_CMPXCHG = DECORATOR_LAST << 3; 43 // This denotes that a load has control dependency. 44 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4; 45 // This denotes that a load that must be pinned, but may float above safepoints. 46 const DecoratorSet C2_UNKNOWN_CONTROL_LOAD = DECORATOR_LAST << 5; 47 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics. 48 const DecoratorSet C2_UNSAFE_ACCESS = DECORATOR_LAST << 6; 49 // This denotes that the access mutates state. 50 const DecoratorSet C2_WRITE_ACCESS = DECORATOR_LAST << 7; 51 // This denotes that the access reads state. 52 const DecoratorSet C2_READ_ACCESS = DECORATOR_LAST << 8; 53 // A nearby allocation? 54 const DecoratorSet C2_TIGHTLY_COUPLED_ALLOC = DECORATOR_LAST << 9; 55 // Loads and stores from an arraycopy being optimized 56 const DecoratorSet C2_ARRAY_COPY = DECORATOR_LAST << 10; 57 // Loads from immutable memory 58 const DecoratorSet C2_IMMUTABLE_MEMORY = DECORATOR_LAST << 11; 59 60 class Compile; 61 class ConnectionGraph; 62 class GraphKit; 63 class IdealKit; 64 class Node; 65 class PhaseGVN; 66 class PhaseIdealLoop; 67 class PhaseMacroExpand; 68 class Type; 69 class TypePtr; 70 class Unique_Node_List; 71 72 // This class wraps a node and a type. 73 class C2AccessValue: public StackObj { 74 protected: 75 Node* _node; 76 const Type* _type; 77 78 public: 79 C2AccessValue(Node* node, const Type* type) : 80 _node(node), 81 _type(type) {} 82 83 Node* node() const { return _node; } 84 const Type* type() const { return _type; } 85 86 void set_node(Node* node) { _node = node; } 87 }; 88 89 // This class wraps a node and a pointer type. 90 class C2AccessValuePtr: public C2AccessValue { 91 92 public: 93 C2AccessValuePtr(Node* node, const TypePtr* type) : 94 C2AccessValue(node, reinterpret_cast<const Type*>(type)) {} 95 96 const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); } 97 }; 98 99 // This class wraps a bunch of context parameters thare are passed around in the 100 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate. 101 class C2Access: public StackObj { 102 protected: 103 DecoratorSet _decorators; 104 BasicType _type; 105 Node* _base; 106 C2AccessValuePtr& _addr; 107 Node* _raw_access; 108 uint8_t _barrier_data; 109 110 void fixup_decorators(); 111 112 public: 113 C2Access(DecoratorSet decorators, 114 BasicType type, Node* base, C2AccessValuePtr& addr) : 115 _decorators(decorators), 116 _type(type), 117 _base(base), 118 _addr(addr), 119 _raw_access(NULL), 120 _barrier_data(0) 121 {} 122 123 DecoratorSet decorators() const { return _decorators; } 124 Node* base() const { return _base; } 125 C2AccessValuePtr& addr() const { return _addr; } 126 BasicType type() const { return _type; } 127 bool is_oop() const { return is_reference_type(_type); } 128 bool is_raw() const { return (_decorators & AS_RAW) != 0; } 129 Node* raw_access() const { return _raw_access; } 130 131 uint8_t barrier_data() const { return _barrier_data; } 132 void set_barrier_data(uint8_t data) { _barrier_data = data; } 133 134 void set_raw_access(Node* raw_access) { _raw_access = raw_access; } 135 virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses. 136 137 MemNode::MemOrd mem_node_mo() const; 138 bool needs_cpu_membar() const; 139 140 virtual PhaseGVN& gvn() const = 0; 141 virtual bool is_parse_access() const { return false; } 142 virtual bool is_opt_access() const { return false; } 143 }; 144 145 // C2Access for parse time calls to the BarrierSetC2 backend. 146 class C2ParseAccess: public C2Access { 147 protected: 148 GraphKit* _kit; 149 150 void* barrier_set_state() const; 151 152 public: 153 C2ParseAccess(GraphKit* kit, DecoratorSet decorators, 154 BasicType type, Node* base, C2AccessValuePtr& addr) : 155 C2Access(decorators, type, base, addr), 156 _kit(kit) { 157 fixup_decorators(); 158 } 159 160 GraphKit* kit() const { return _kit; } 161 162 virtual PhaseGVN& gvn() const; 163 virtual bool is_parse_access() const { return true; } 164 }; 165 166 // This class wraps a bunch of context parameters thare are passed around in the 167 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate. 168 class C2AtomicParseAccess: public C2ParseAccess { 169 Node* _memory; 170 uint _alias_idx; 171 bool _needs_pinning; 172 173 public: 174 C2AtomicParseAccess(GraphKit* kit, DecoratorSet decorators, BasicType type, 175 Node* base, C2AccessValuePtr& addr, uint alias_idx) : 176 C2ParseAccess(kit, decorators, type, base, addr), 177 _memory(NULL), 178 _alias_idx(alias_idx), 179 _needs_pinning(true) {} 180 181 // Set the memory node based on the current memory slice. 182 virtual void set_memory(); 183 184 Node* memory() const { return _memory; } 185 uint alias_idx() const { return _alias_idx; } 186 bool needs_pinning() const { return _needs_pinning; } 187 }; 188 189 // C2Access for optimization time calls to the BarrierSetC2 backend. 190 class C2OptAccess: public C2Access { 191 PhaseGVN& _gvn; 192 MergeMemNode* _mem; 193 Node* _ctl; 194 195 public: 196 C2OptAccess(PhaseGVN& gvn, Node* ctl, MergeMemNode* mem, DecoratorSet decorators, 197 BasicType type, Node* base, C2AccessValuePtr& addr) : 198 C2Access(decorators, type, base, addr), 199 _gvn(gvn), _mem(mem), _ctl(ctl) { 200 fixup_decorators(); 201 } 202 203 MergeMemNode* mem() const { return _mem; } 204 Node* ctl() const { return _ctl; } 205 206 virtual PhaseGVN& gvn() const { return _gvn; } 207 virtual bool is_opt_access() const { return true; } 208 }; 209 210 211 // This is the top-level class for the backend of the Access API in C2. 212 // The top-level class is responsible for performing raw accesses. The 213 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle 214 // barriers into the accesses. 215 class BarrierSetC2: public CHeapObj<mtGC> { 216 protected: 217 virtual void resolve_address(C2Access& access) const; 218 virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const; 219 virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const; 220 221 virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val, 222 Node* new_val, const Type* val_type) const; 223 virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val, 224 Node* new_val, const Type* value_type) const; 225 virtual Node* atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const; 226 virtual Node* atomic_add_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const; 227 void pin_atomic_op(C2AtomicParseAccess& access) const; 228 229 public: 230 // This is the entry-point for the backend to perform accesses through the Access API. 231 virtual Node* store_at(C2Access& access, C2AccessValue& val) const; 232 virtual Node* load_at(C2Access& access, const Type* val_type) const; 233 234 virtual Node* atomic_cmpxchg_val_at(C2AtomicParseAccess& access, Node* expected_val, 235 Node* new_val, const Type* val_type) const; 236 virtual Node* atomic_cmpxchg_bool_at(C2AtomicParseAccess& access, Node* expected_val, 237 Node* new_val, const Type* val_type) const; 238 virtual Node* atomic_xchg_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const; 239 virtual Node* atomic_add_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const; 240 241 virtual void clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const; 242 243 virtual Node* obj_allocate(PhaseMacroExpand* macro, Node* mem, Node* toobig_false, Node* size_in_bytes, 244 Node*& i_o, Node*& needgc_ctrl, 245 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem, 246 intx prefetch_lines) const; 247 248 virtual Node* ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const { return NULL; } 249 250 // These are general helper methods used by C2 251 enum ArrayCopyPhase { 252 Parsing, 253 Optimization, 254 Expansion 255 }; 256 257 virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, bool is_clone_instance, ArrayCopyPhase phase) const { return false; } 258 virtual void clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const; 259 260 // Support for GC barriers emitted during parsing 261 virtual bool has_load_barrier_nodes() const { return false; } 262 virtual bool is_gc_barrier_node(Node* node) const { return false; } 263 virtual Node* step_over_gc_barrier(Node* c) const { return c; } 264 265 // Support for macro expanded GC barriers 266 virtual void register_potential_barrier_node(Node* node) const { } 267 virtual void unregister_potential_barrier_node(Node* node) const { } 268 virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { } 269 virtual void enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {} 270 virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {} 271 272 // Allow barrier sets to have shared state that is preserved across a compilation unit. 273 // This could for example comprise macro nodes to be expanded during macro expansion. 274 virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; } 275 // If the BarrierSetC2 state has barrier nodes in its compilation 276 // unit state to be expanded later, then now is the time to do so. 277 virtual bool expand_barriers(Compile* C, PhaseIterGVN& igvn) const { return false; } 278 virtual bool optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const { return false; } 279 virtual bool strip_mined_loops_expanded(LoopOptsMode mode) const { return false; } 280 virtual bool is_gc_specific_loop_opts_pass(LoopOptsMode mode) const { return false; } 281 282 enum CompilePhase { 283 BeforeOptimize, 284 BeforeMacroExpand, 285 BeforeCodeGen 286 }; 287 288 #ifdef ASSERT 289 virtual void verify_gc_barriers(Compile* compile, CompilePhase phase) const {} 290 #endif 291 292 virtual bool final_graph_reshaping(Compile* compile, Node* n, uint opcode) const { return false; } 293 294 virtual bool escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const { return false; } 295 virtual bool escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const { return false; } 296 virtual bool escape_has_out_with_unsafe_object(Node* n) const { return false; } 297 298 virtual bool matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const { return false; }; 299 virtual bool matcher_is_store_load_barrier(Node* x, uint xop) const { return false; } 300 301 virtual void late_barrier_analysis() const { } 302 virtual int estimate_stub_size() const { return 0; } 303 virtual void emit_stubs(CodeBuffer& cb) const { } 304 305 static int arraycopy_payload_base_offset(bool is_array); 306 }; 307 308 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP