1 /*
   2  * Copyright (c) 2018, 2019, 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.
  46 const DecoratorSet C2_PINNED_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 
  58 class Compile;
  59 class ConnectionGraph;
  60 class GraphKit;
  61 class IdealKit;
  62 class Node;
  63 class PhaseGVN;
  64 class PhaseIdealLoop;
  65 class PhaseMacroExpand;
  66 class Type;
  67 class TypePtr;
  68 class Unique_Node_List;
  69 
  70 // This class wraps a node and a type.
  71 class C2AccessValue: public StackObj {
  72 protected:
  73   Node* _node;
  74   const Type* _type;
  75 
  76 public:
  77   C2AccessValue(Node* node, const Type* type) :
  78     _node(node),
  79     _type(type) {}
  80 
  81   Node* node() const        { return _node; }
  82   const Type* type() const  { return _type; }
  83 
  84   void set_node(Node* node) { _node = node; }
  85 };
  86 
  87 // This class wraps a node and a pointer type.
  88 class C2AccessValuePtr: public C2AccessValue {
  89 
  90 public:
  91   C2AccessValuePtr(Node* node, const TypePtr* type) :
  92     C2AccessValue(node, reinterpret_cast<const Type*>(type)) {}
  93 
  94   const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); }
  95 };
  96 
  97 // This class wraps a bunch of context parameters thare are passed around in the
  98 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
  99 class C2Access: public StackObj {
 100 protected:
 101   DecoratorSet      _decorators;
 102   BasicType         _type;
 103   Node*             _base;
 104   C2AccessValuePtr& _addr;
 105   Node*             _raw_access;
 106 
 107   void fixup_decorators();
 108 
 109 public:
 110   C2Access(DecoratorSet decorators,
 111            BasicType type, Node* base, C2AccessValuePtr& addr) :
 112     _decorators(decorators),
 113     _type(type),
 114     _base(base),
 115     _addr(addr),
 116     _raw_access(NULL)
 117   {}
 118 
 119   DecoratorSet decorators() const { return _decorators; }
 120   Node* base() const              { return _base; }
 121   C2AccessValuePtr& addr() const  { return _addr; }
 122   BasicType type() const          { return _type; }
 123   bool is_oop() const             { return _type == T_OBJECT || _type == T_ARRAY; }
 124   bool is_raw() const             { return (_decorators & AS_RAW) != 0; }
 125   Node* raw_access() const        { return _raw_access; }
 126 
 127   void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
 128   virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.
 129 
 130   MemNode::MemOrd mem_node_mo() const;
 131   bool needs_cpu_membar() const;
 132 
 133   virtual PhaseGVN& gvn() const = 0;
 134   virtual bool is_parse_access() const { return false; }
 135   virtual bool is_opt_access() const { return false; }
 136 };
 137 
 138 // C2Access for parse time calls to the BarrierSetC2 backend.
 139 class C2ParseAccess: public C2Access {
 140 protected:
 141   GraphKit*         _kit;
 142 
 143   void* barrier_set_state() const;
 144 
 145 public:
 146   C2ParseAccess(GraphKit* kit, DecoratorSet decorators,
 147                 BasicType type, Node* base, C2AccessValuePtr& addr) :
 148     C2Access(decorators, type, base, addr),
 149     _kit(kit) {
 150     fixup_decorators();
 151   }
 152 
 153   GraphKit* kit() const           { return _kit; }
 154 
 155   template <typename T>
 156   T barrier_set_state_as() const {
 157     return reinterpret_cast<T>(barrier_set_state());
 158   }
 159 
 160   virtual PhaseGVN& gvn() const;
 161   virtual bool is_parse_access() const { return true; }
 162 };
 163 
 164 // This class wraps a bunch of context parameters thare are passed around in the
 165 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
 166 class C2AtomicParseAccess: public C2ParseAccess {
 167   Node* _memory;
 168   uint  _alias_idx;
 169   bool  _needs_pinning;
 170 
 171 public:
 172   C2AtomicParseAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
 173                  Node* base, C2AccessValuePtr& addr, uint alias_idx) :
 174     C2ParseAccess(kit, decorators, type, base, addr),
 175     _memory(NULL),
 176     _alias_idx(alias_idx),
 177     _needs_pinning(true) {}
 178 
 179   // Set the memory node based on the current memory slice.
 180   virtual void set_memory();
 181 
 182   Node* memory() const       { return _memory; }
 183   uint alias_idx() const     { return _alias_idx; }
 184   bool needs_pinning() const { return _needs_pinning; }
 185 
 186   void set_needs_pinning(bool value)    { _needs_pinning = value; }
 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 
 204   MergeMemNode* mem() const { return _mem; }
 205   Node* ctl() const { return _ctl; }
 206   // void set_mem(Node* mem) { _mem = mem; }
 207   void set_ctl(Node* ctl) { _ctl = ctl; }
 208 
 209   virtual PhaseGVN& gvn() const { return _gvn; }
 210   virtual bool is_opt_access() const { return true; }
 211 };
 212 
 213 
 214 // This is the top-level class for the backend of the Access API in C2.
 215 // The top-level class is responsible for performing raw accesses. The
 216 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle
 217 // barriers into the accesses.
 218 class BarrierSetC2: public CHeapObj<mtGC> {
 219 protected:
 220   virtual void resolve_address(C2Access& access) const;
 221   virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
 222   virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;
 223 
 224   virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 225                                                Node* new_val, const Type* val_type) const;
 226   virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 227                                                 Node* new_val, const Type* value_type) const;
 228   virtual Node* atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
 229   virtual Node* atomic_add_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
 230   void pin_atomic_op(C2AtomicParseAccess& access) const;
 231 
 232 public:
 233   // This is the entry-point for the backend to perform accesses through the Access API.
 234   virtual Node* store_at(C2Access& access, C2AccessValue& val) const;
 235   virtual Node* load_at(C2Access& access, const Type* val_type) const;
 236 
 237   virtual Node* atomic_cmpxchg_val_at(C2AtomicParseAccess& access, Node* expected_val,
 238                                       Node* new_val, const Type* val_type) const;
 239   virtual Node* atomic_cmpxchg_bool_at(C2AtomicParseAccess& access, Node* expected_val,
 240                                        Node* new_val, const Type* val_type) const;
 241   virtual Node* atomic_xchg_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const;
 242   virtual Node* atomic_add_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const;
 243 
 244   virtual void clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const;
 245 
 246   virtual Node* resolve(GraphKit* kit, Node* n, DecoratorSet decorators) const { return n; }
 247 
 248   virtual Node* obj_allocate(PhaseMacroExpand* macro, Node* ctrl, Node* mem, Node* toobig_false, Node* size_in_bytes,
 249                              Node*& i_o, Node*& needgc_ctrl,
 250                              Node*& fast_oop_ctrl, Node*& fast_oop_rawmem,
 251                              intx prefetch_lines) const;
 252 
 253   virtual Node* ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const { return NULL; }
 254   virtual Node* identity_node(PhaseGVN* phase, Node* n) const { return n; }
 255 
 256   // These are general helper methods used by C2
 257   enum ArrayCopyPhase {
 258     Parsing,
 259     Optimization,
 260     Expansion
 261   };
 262   virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const { return false; }
 263   virtual void clone_barrier_at_expansion(ArrayCopyNode* ac, Node* call, PhaseIterGVN& igvn) const;
 264 
 265   // Support for GC barriers emitted during parsing
 266   virtual bool has_load_barriers() const { return false; }
 267   virtual bool is_gc_barrier_node(Node* node) const { return false; }
 268   virtual Node* step_over_gc_barrier(Node* c) const { return c; }
 269 
 270   // Support for macro expanded GC barriers
 271   virtual void register_potential_barrier_node(Node* node) const { }
 272   virtual void unregister_potential_barrier_node(Node* node) const { }
 273   virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { }
 274   virtual void enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {}
 275   virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {}
 276   virtual void add_users_to_worklist(Unique_Node_List* worklist) const {}
 277 
 278   // Allow barrier sets to have shared state that is preserved across a compilation unit.
 279   // This could for example comprise macro nodes to be expanded during macro expansion.
 280   virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; }
 281   // If the BarrierSetC2 state has barrier nodes in its compilation
 282   // unit state to be expanded later, then now is the time to do so.
 283   virtual bool expand_barriers(Compile* C, PhaseIterGVN& igvn) const { return false; }
 284   virtual bool optimize_loops(PhaseIdealLoop* phase, LoopOptsMode mode, VectorSet& visited, Node_Stack& nstack, Node_List& worklist) const { return false; }
 285   virtual bool strip_mined_loops_expanded(LoopOptsMode mode) const { return false; }
 286   virtual bool is_gc_specific_loop_opts_pass(LoopOptsMode mode) const { return false; }
 287 
 288   virtual bool has_special_unique_user(const Node* node) const { return false; }
 289 
 290   enum CompilePhase {
 291     BeforeOptimize, /* post_parse = true */
 292     BeforeExpand, /* post_parse = false */
 293     BeforeCodeGen
 294   };
 295   virtual void verify_gc_barriers(Compile* compile, CompilePhase phase) const {}
 296 
 297   virtual bool flatten_gc_alias_type(const TypePtr*& adr_type) const { return false; }
 298 #ifdef ASSERT
 299   virtual bool verify_gc_alias_type(const TypePtr* adr_type, int offset) const { return false; }
 300 #endif
 301 
 302   virtual bool final_graph_reshaping(Compile* compile, Node* n, uint opcode) const { return false; }
 303 
 304   virtual bool escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const { return false; }
 305   virtual bool escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const { return false; }
 306   virtual bool escape_has_out_with_unsafe_object(Node* n) const { return false; }
 307   virtual bool escape_is_barrier_node(Node* n) const { return false; }
 308 
 309   virtual bool matcher_find_shared_visit(Matcher* matcher, Matcher::MStack& mstack, Node* n, uint opcode, bool& mem_op, int& mem_addr_idx) const { return false; };
 310   virtual bool matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const { return false; };
 311   virtual bool matcher_is_store_load_barrier(Node* x, uint xop) const { return false; }
 312 
 313   virtual void igvn_add_users_to_worklist(PhaseIterGVN* igvn, Node* use) const {}
 314   virtual void ccp_analyze(PhaseCCP* ccp, Unique_Node_List& worklist, Node* use) const {}
 315 
 316   virtual Node* split_if_pre(PhaseIdealLoop* phase, Node* n) const { return NULL; }
 317   virtual bool build_loop_late_post(PhaseIdealLoop* phase, Node* n) const { return false; }
 318   virtual bool sink_node(PhaseIdealLoop* phase, Node* n, Node* x, Node* x_ctrl, Node* n_ctrl) const { return false; }
 319 };
 320 
 321 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP