1 /* 2 * Copyright (c) 2018, 2023, 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/machnode.hpp" 32 #include "opto/matcher.hpp" 33 #include "opto/memnode.hpp" 34 #include "utilities/globalDefinitions.hpp" 35 36 // This means the access is mismatched. This means the value of an access 37 // is not equivalent to the value pointed to by the address. 38 const DecoratorSet C2_MISMATCHED = DECORATOR_LAST << 1; 39 // The access may not be aligned to its natural size. 40 const DecoratorSet C2_UNALIGNED = DECORATOR_LAST << 2; 41 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed, 42 // but never false positives. 43 const DecoratorSet C2_WEAK_CMPXCHG = DECORATOR_LAST << 3; 44 // This denotes that a load has control dependency. 45 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4; 46 // This denotes that a load that must be pinned, but may float above safepoints. 47 const DecoratorSet C2_UNKNOWN_CONTROL_LOAD = DECORATOR_LAST << 5; 48 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics. 49 const DecoratorSet C2_UNSAFE_ACCESS = DECORATOR_LAST << 6; 50 // This denotes that the access mutates state. 51 const DecoratorSet C2_WRITE_ACCESS = DECORATOR_LAST << 7; 52 // This denotes that the access reads state. 53 const DecoratorSet C2_READ_ACCESS = DECORATOR_LAST << 8; 54 // A nearby allocation? 55 const DecoratorSet C2_TIGHTLY_COUPLED_ALLOC = DECORATOR_LAST << 9; 56 // Loads and stores from an arraycopy being optimized 57 const DecoratorSet C2_ARRAY_COPY = DECORATOR_LAST << 10; 58 // Loads from immutable memory 59 const DecoratorSet C2_IMMUTABLE_MEMORY = DECORATOR_LAST << 11; 60 61 class Compile; 62 class ConnectionGraph; 63 class GraphKit; 64 class IdealKit; 65 class Node; 66 class PhaseGVN; 67 class PhaseIdealLoop; 68 class PhaseMacroExpand; 69 class Type; 70 class TypePtr; 71 class Unique_Node_List; 72 73 // This class wraps a node and a type. 74 class C2AccessValue: public StackObj { 75 protected: 76 Node* _node; 77 const Type* _type; 78 79 public: 80 C2AccessValue(Node* node, const Type* type) : 81 _node(node), 82 _type(type) {} 83 84 Node* node() const { return _node; } 85 const Type* type() const { return _type; } 86 87 void set_node(Node* node) { _node = node; } 88 }; 89 90 // This class wraps a node and a pointer type. 91 class C2AccessValuePtr: public C2AccessValue { 92 93 public: 94 C2AccessValuePtr(Node* node, const TypePtr* type) : 95 C2AccessValue(node, reinterpret_cast<const Type*>(type)) {} 96 97 const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); } 98 }; 99 100 // This class wraps a bunch of context parameters that are passed around in the 101 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate. 102 class C2Access: public StackObj { 103 protected: 104 DecoratorSet _decorators; 105 BasicType _type; 106 Node* _base; 107 C2AccessValuePtr& _addr; 108 Node* _raw_access; 109 uint8_t _barrier_data; 110 111 void fixup_decorators(); 112 113 public: 114 C2Access(DecoratorSet decorators, 115 BasicType type, Node* base, C2AccessValuePtr& addr) : 116 _decorators(decorators), 117 _type(type), 118 _base(base), 119 _addr(addr), 120 _raw_access(nullptr), 121 _barrier_data(0) 122 {} 123 124 DecoratorSet decorators() const { return _decorators; } 125 Node* base() const { return _base; } 126 C2AccessValuePtr& addr() const { return _addr; } 127 BasicType type() const { return _type; } 128 bool is_oop() const { return is_reference_type(_type); } 129 bool is_raw() const { return (_decorators & AS_RAW) != 0; } 130 Node* raw_access() const { return _raw_access; } 131 132 uint8_t barrier_data() const { return _barrier_data; } 133 void set_barrier_data(uint8_t data) { _barrier_data = data; } 134 135 void set_raw_access(Node* raw_access) { _raw_access = raw_access; } 136 virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses. 137 138 MemNode::MemOrd mem_node_mo() const; 139 bool needs_cpu_membar() const; 140 141 virtual PhaseGVN& gvn() const = 0; 142 virtual bool is_parse_access() const { return false; } 143 virtual bool is_opt_access() const { return false; } 144 }; 145 146 // C2Access for parse time calls to the BarrierSetC2 backend. 147 class C2ParseAccess: public C2Access { 148 protected: 149 GraphKit* _kit; 150 Node* _ctl; 151 152 void* barrier_set_state() const; 153 154 public: 155 C2ParseAccess(GraphKit* kit, DecoratorSet decorators, 156 BasicType type, Node* base, C2AccessValuePtr& addr, 157 Node* ctl = nullptr) : 158 C2Access(decorators, type, base, addr), 159 _kit(kit), 160 _ctl(ctl) { 161 fixup_decorators(); 162 } 163 164 GraphKit* kit() const { return _kit; } 165 Node* control() const; 166 167 virtual PhaseGVN& gvn() const; 168 virtual bool is_parse_access() const { return true; } 169 }; 170 171 // This class wraps a bunch of context parameters that are passed around in the 172 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate. 173 class C2AtomicParseAccess: public C2ParseAccess { 174 Node* _memory; 175 uint _alias_idx; 176 177 public: 178 C2AtomicParseAccess(GraphKit* kit, DecoratorSet decorators, BasicType type, 179 Node* base, C2AccessValuePtr& addr, uint alias_idx) : 180 C2ParseAccess(kit, decorators, type, base, addr), 181 _memory(nullptr), 182 _alias_idx(alias_idx) {} 183 184 // Set the memory node based on the current memory slice. 185 virtual void set_memory(); 186 187 Node* memory() const { return _memory; } 188 uint alias_idx() const { return _alias_idx; } 189 }; 190 191 // C2Access for optimization time calls to the BarrierSetC2 backend. 192 class C2OptAccess: public C2Access { 193 PhaseGVN& _gvn; 194 MergeMemNode* _mem; 195 Node* _ctl; 196 197 public: 198 C2OptAccess(PhaseGVN& gvn, Node* ctl, MergeMemNode* mem, DecoratorSet decorators, 199 BasicType type, Node* base, C2AccessValuePtr& addr) : 200 C2Access(decorators, type, base, addr), 201 _gvn(gvn), _mem(mem), _ctl(ctl) { 202 fixup_decorators(); 203 } 204 205 MergeMemNode* mem() const { return _mem; } 206 Node* ctl() const { return _ctl; } 207 208 virtual PhaseGVN& gvn() const { return _gvn; } 209 virtual bool is_opt_access() const { return true; } 210 }; 211 212 213 // This is the top-level class for the backend of the Access API in C2. 214 // The top-level class is responsible for performing raw accesses. The 215 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle 216 // barriers into the accesses. 217 class BarrierSetC2: public CHeapObj<mtGC> { 218 protected: 219 virtual void resolve_address(C2Access& access) const; 220 virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const; 221 virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const; 222 223 virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val, 224 Node* new_val, const Type* val_type) const; 225 virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val, 226 Node* new_val, const Type* value_type) const; 227 virtual Node* atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const; 228 virtual Node* atomic_add_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const; 229 void pin_atomic_op(C2AtomicParseAccess& access) const; 230 231 public: 232 // This is the entry-point for the backend to perform accesses through the Access API. 233 virtual Node* store_at(C2Access& access, C2AccessValue& val) const; 234 virtual Node* load_at(C2Access& access, const Type* val_type) const; 235 236 virtual Node* atomic_cmpxchg_val_at(C2AtomicParseAccess& access, Node* expected_val, 237 Node* new_val, const Type* val_type) const; 238 virtual Node* atomic_cmpxchg_bool_at(C2AtomicParseAccess& access, Node* expected_val, 239 Node* new_val, const Type* val_type) const; 240 virtual Node* atomic_xchg_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const; 241 virtual Node* atomic_add_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const; 242 243 virtual void clone(GraphKit* kit, Node* src_base, Node* dst_base, Node* size, bool is_array) const; 244 245 virtual Node* obj_allocate(PhaseMacroExpand* macro, Node* mem, Node* toobig_false, Node* size_in_bytes, 246 Node*& i_o, Node*& needgc_ctrl, 247 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem, 248 intx prefetch_lines) const; 249 250 virtual Node* ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const { return nullptr; } 251 252 // These are general helper methods used by C2 253 enum ArrayCopyPhase { 254 Parsing, 255 Optimization, 256 Expansion 257 }; 258 259 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; } 260 virtual void clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const; 261 262 // Support for GC barriers emitted during parsing 263 virtual bool has_load_barrier_nodes() const { return false; } 264 virtual bool is_gc_pre_barrier_node(Node* node) const { return false; } 265 virtual bool is_gc_barrier_node(Node* node) const { return false; } 266 virtual Node* step_over_gc_barrier(Node* c) const { return c; } 267 268 // Support for macro expanded GC barriers 269 virtual void register_potential_barrier_node(Node* node) const { } 270 virtual void unregister_potential_barrier_node(Node* node) const { } 271 virtual void eliminate_gc_barrier(PhaseIterGVN* igvn, Node* node) const { } 272 virtual void eliminate_gc_barrier_data(Node* node) const { } 273 virtual void enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {} 274 virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {} 275 276 // Allow barrier sets to have shared state that is preserved across a compilation unit. 277 // This could for example comprise macro nodes to be expanded during macro expansion. 278 virtual void* create_barrier_state(Arena* comp_arena) const { return nullptr; } 279 // If the BarrierSetC2 state has barrier nodes in its compilation 280 // unit state to be expanded later, then now is the time to do so. 281 virtual bool expand_barriers(Compile* C, PhaseIterGVN& igvn) const { return false; } 282 virtual bool optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const { return false; } 283 virtual bool strip_mined_loops_expanded(LoopOptsMode mode) const { return false; } 284 virtual bool is_gc_specific_loop_opts_pass(LoopOptsMode mode) const { return false; } 285 286 enum CompilePhase { 287 BeforeOptimize, 288 BeforeMacroExpand, 289 BeforeCodeGen 290 }; 291 292 #ifdef ASSERT 293 virtual void verify_gc_barriers(Compile* compile, CompilePhase phase) const {} 294 #endif 295 296 virtual bool final_graph_reshaping(Compile* compile, Node* n, uint opcode, Unique_Node_List& dead_nodes) const { return false; } 297 298 virtual bool escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const { return false; } 299 virtual bool escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const { return false; } 300 virtual bool escape_has_out_with_unsafe_object(Node* n) const { return false; } 301 302 virtual bool matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const { return false; }; 303 virtual bool matcher_is_store_load_barrier(Node* x, uint xop) const { return false; } 304 305 virtual void late_barrier_analysis() const { } 306 virtual int estimate_stub_size() const { return 0; } 307 virtual void emit_stubs(CodeBuffer& cb) const { } 308 309 static int arraycopy_payload_base_offset(bool is_array); 310 311 #ifndef PRODUCT 312 virtual void dump_barrier_data(const MachNode* mach, outputStream* st) const { 313 st->print("%x", mach->barrier_data()); 314 }; 315 #endif 316 }; 317 318 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP