1 /*
   2  * Copyright (c) 2018, 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_TIGHLY_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 PhaseMacroExpand;
  65 class Type;
  66 class TypePtr;
  67 class Unique_Node_List;
  68 
  69 // This class wraps a node and a type.
  70 class C2AccessValue: public StackObj {
  71 protected:
  72   Node* _node;
  73   const Type* _type;
  74 
  75 public:
  76   C2AccessValue(Node* node, const Type* type) :
  77     _node(node),
  78     _type(type) {}
  79 
  80   Node* node() const        { return _node; }
  81   const Type* type() const  { return _type; }
  82 
  83   void set_node(Node* node) { _node = node; }
  84 };
  85 
  86 // This class wraps a node and a pointer type.
  87 class C2AccessValuePtr: public C2AccessValue {
  88 
  89 public:
  90   C2AccessValuePtr(Node* node, const TypePtr* type) :
  91     C2AccessValue(node, reinterpret_cast<const Type*>(type)) {}
  92 
  93   const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); }
  94 };
  95 
  96 // This class wraps a bunch of context parameters thare are passed around in the
  97 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
  98 class C2Access: public StackObj {
  99 protected:
 100   DecoratorSet      _decorators;
 101   BasicType         _type;
 102   Node*             _base;
 103   C2AccessValuePtr& _addr;
 104   Node*             _raw_access;
 105 
 106   void fixup_decorators();
 107 
 108 public:
 109   C2Access(DecoratorSet decorators,
 110            BasicType type, Node* base, C2AccessValuePtr& addr) :
 111     _decorators(decorators),
 112     _type(type),
 113     _base(base),
 114     _addr(addr),
 115     _raw_access(NULL)
 116   {}
 117 
 118   DecoratorSet decorators() const { return _decorators; }
 119   Node* base() const              { return _base; }
 120   C2AccessValuePtr& addr() const  { return _addr; }
 121   BasicType type() const          { return _type; }
 122   bool is_oop() const             { return _type == T_OBJECT || _type == T_ARRAY; }
 123   bool is_raw() const             { return (_decorators & AS_RAW) != 0; }
 124   Node* raw_access() const        { return _raw_access; }
 125 
 126   void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
 127   virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.
 128 
 129   MemNode::MemOrd mem_node_mo() const;
 130   bool needs_cpu_membar() const;
 131 
 132   virtual PhaseGVN& gvn() const = 0;
 133   virtual bool is_parse_access() const { return false; }
 134   virtual bool is_opt_access() const { return false; }
 135 };
 136 
 137 // C2Access for parse time calls to the BarrierSetC2 backend.
 138 class C2ParseAccess: public C2Access {
 139 protected:
 140   GraphKit*         _kit;
 141 
 142   void* barrier_set_state() const;
 143 
 144 public:
 145   C2ParseAccess(GraphKit* kit, DecoratorSet decorators,
 146                 BasicType type, Node* base, C2AccessValuePtr& addr) :
 147     C2Access(decorators, type, base, addr),
 148     _kit(kit) {
 149     fixup_decorators();
 150   }
 151 
 152   GraphKit* kit() const           { return _kit; }
 153 
 154   template <typename T>
 155   T barrier_set_state_as() const {
 156     return reinterpret_cast<T>(barrier_set_state());
 157   }
 158 
 159   virtual PhaseGVN& gvn() const;
 160   virtual bool is_parse_access() const { return true; }
 161 };
 162 
 163 // This class wraps a bunch of context parameters thare are passed around in the
 164 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
 165 class C2AtomicParseAccess: public C2ParseAccess {
 166   Node* _memory;
 167   uint  _alias_idx;
 168   bool  _needs_pinning;
 169 
 170 public:
 171   C2AtomicParseAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
 172                  Node* base, C2AccessValuePtr& addr, uint alias_idx) :
 173     C2ParseAccess(kit, decorators, type, base, addr),
 174     _memory(NULL),
 175     _alias_idx(alias_idx),
 176     _needs_pinning(true) {}
 177 
 178   // Set the memory node based on the current memory slice.
 179   virtual void set_memory();
 180 
 181   Node* memory() const       { return _memory; }
 182   uint alias_idx() const     { return _alias_idx; }
 183   bool needs_pinning() const { return _needs_pinning; }
 184 
 185   void set_needs_pinning(bool value)    { _needs_pinning = value; }
 186 };
 187 
 188 // C2Access for optimization time calls to the BarrierSetC2 backend.
 189 class C2OptAccess: public C2Access {
 190   PhaseGVN& _gvn;
 191   MergeMemNode* _mem;
 192   Node* _ctl;
 193 
 194 public:
 195   C2OptAccess(PhaseGVN& gvn, Node* ctl, MergeMemNode* mem, DecoratorSet decorators,
 196               BasicType type, Node* base, C2AccessValuePtr& addr) :
 197     C2Access(decorators, type, base, addr),
 198     _gvn(gvn), _mem(mem), _ctl(ctl) {
 199     fixup_decorators();
 200   }
 201 
 202 
 203   MergeMemNode* mem() const { return _mem; }
 204   Node* ctl() const { return _ctl; }
 205   // void set_mem(Node* mem) { _mem = mem; }
 206   void set_ctl(Node* ctl) { _ctl = 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, Node* dst, Node* size, bool is_array) const;
 244 
 245   virtual Node* resolve(GraphKit* kit, Node* n, DecoratorSet decorators) const { return n; }
 246 
 247   virtual Node* obj_allocate(PhaseMacroExpand* macro, Node* ctrl, Node* mem, Node* toobig_false, Node* size_in_bytes,
 248                              Node*& i_o, Node*& needgc_ctrl,
 249                              Node*& fast_oop_ctrl, Node*& fast_oop_rawmem,
 250                              intx prefetch_lines) const;
 251 
 252   virtual Node* ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const { return NULL; }
 253   virtual Node* identity_node(PhaseGVN* phase, Node* n) const { return n; }
 254 
 255   // These are general helper methods used by C2
 256   enum ArrayCopyPhase {
 257     Parsing,
 258     Optimization,
 259     Expansion
 260   };
 261   virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const { return false; }
 262   virtual void clone_barrier_at_expansion(ArrayCopyNode* ac, Node* call, PhaseIterGVN& igvn) const;
 263 
 264   // Support for GC barriers emitted during parsing
 265   virtual bool has_load_barriers() const { return false; }
 266   virtual bool is_gc_barrier_node(Node* node) const { return false; }
 267   virtual Node* step_over_gc_barrier(Node* c) const { return c; }
 268 
 269   // Support for macro expanded GC barriers
 270   virtual void register_potential_barrier_node(Node* node) const { }
 271   virtual void unregister_potential_barrier_node(Node* node) const { }
 272   virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, 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   virtual void add_users_to_worklist(Unique_Node_List* worklist) const {}
 276 
 277   // Allow barrier sets to have shared state that is preserved across a compilation unit.
 278   // This could for example comprise macro nodes to be expanded during macro expansion.
 279   virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; }
 280   // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
 281   // expanded later, then now is the time to do so.
 282   virtual bool expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
 283 
 284   virtual bool has_special_unique_user(const Node* node) const { return false; }
 285 
 286   enum CompilePhase {
 287     BeforeOptimize, /* post_parse = true */
 288     BeforeExpand, /* post_parse = false */
 289     BeforeCodeGen
 290   };
 291   virtual void verify_gc_barriers(Compile* compile, CompilePhase phase) const {}
 292 
 293   virtual bool flatten_gc_alias_type(const TypePtr*& adr_type) const { return false; }
 294 #ifdef ASSERT
 295   virtual bool verify_gc_alias_type(const TypePtr* adr_type, int offset) const { return false; }
 296 #endif
 297 
 298   virtual bool final_graph_reshaping(Compile* compile, Node* n, uint opcode) const { return false; }
 299 
 300   virtual bool escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const { return false; }
 301   virtual bool escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const { return false; }
 302   virtual bool escape_has_out_with_unsafe_object(Node* n) const { return false; }
 303   virtual bool escape_is_barrier_node(Node* n) const { return false; }
 304 
 305   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; };
 306   virtual bool matcher_find_shared_post_visit(Matcher* matcher, Node* n, uint opcode) const { return false; };
 307   virtual bool matcher_is_store_load_barrier(Node* x, uint xop) const { return false; }
 308 
 309   virtual void igvn_add_users_to_worklist(PhaseIterGVN* igvn, Node* use) const {}
 310   virtual void ccp_analyze(PhaseCCP* ccp, Unique_Node_List& worklist, Node* use) const {}
 311 
 312 };
 313 
 314 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP