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/memnode.hpp"
  32 #include "utilities/globalDefinitions.hpp"
  33 
  34 // This means the access is mismatched. This means the value of an access
  35 // is not equivalent to the value pointed to by the address.
  36 const DecoratorSet C2_MISMATCHED             = DECORATOR_LAST << 1;
  37 // The access may not be aligned to its natural size.
  38 const DecoratorSet C2_UNALIGNED              = DECORATOR_LAST << 2;
  39 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed,
  40 // but never false positives.
  41 const DecoratorSet C2_WEAK_CMPXCHG           = DECORATOR_LAST << 3;
  42 // This denotes that a load has control dependency.
  43 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4;
  44 // This denotes that a load that must be pinned.
  45 const DecoratorSet C2_PINNED_LOAD            = DECORATOR_LAST << 5;
  46 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics.
  47 const DecoratorSet C2_UNSAFE_ACCESS          = DECORATOR_LAST << 6;
  48 // This denotes that the access mutates state.
  49 const DecoratorSet C2_WRITE_ACCESS           = DECORATOR_LAST << 7;
  50 // This denotes that the access reads state.
  51 const DecoratorSet C2_READ_ACCESS            = DECORATOR_LAST << 8;
  52 // A nearby allocation?
  53 const DecoratorSet C2_TIGHLY_COUPLED_ALLOC   = DECORATOR_LAST << 9;
  54 // Loads and stores from an arraycopy being optimized
  55 const DecoratorSet C2_ARRAY_COPY             = DECORATOR_LAST << 10;
  56 
  57 class GraphKit;
  58 class IdealKit;
  59 class Node;
  60 class Type;
  61 class TypePtr;
  62 class PhaseMacroExpand;
  63 
  64 // This class wraps a node and a type.
  65 class C2AccessValue: public StackObj {
  66 protected:
  67   Node* _node;
  68   const Type* _type;
  69 
  70 public:
  71   C2AccessValue(Node* node, const Type* type) :
  72     _node(node),
  73     _type(type) {}
  74 
  75   Node* node() const        { return _node; }
  76   const Type* type() const  { return _type; }
  77 
  78   void set_node(Node* node) { _node = node; }
  79 };
  80 
  81 // This class wraps a node and a pointer type.
  82 class C2AccessValuePtr: public C2AccessValue {
  83 
  84 public:
  85   C2AccessValuePtr(Node* node, const TypePtr* type) :
  86     C2AccessValue(node, reinterpret_cast<const Type*>(type)) {}
  87 
  88   const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); }
  89 };
  90 
  91 // This class wraps a bunch of context parameters thare are passed around in the
  92 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
  93 class C2Access: public StackObj {
  94 protected:
  95   DecoratorSet      _decorators;
  96   BasicType         _type;
  97   Node*             _base;
  98   C2AccessValuePtr& _addr;
  99   Node*             _raw_access;
 100 
 101   void fixup_decorators();
 102 
 103 public:
 104   C2Access(DecoratorSet decorators,
 105            BasicType type, Node* base, C2AccessValuePtr& addr) :
 106     _decorators(decorators),
 107     _type(type),
 108     _base(base),
 109     _addr(addr),
 110     _raw_access(NULL)
 111   {}
 112 
 113   DecoratorSet decorators() const { return _decorators; }
 114   Node* base() const              { return _base; }
 115   C2AccessValuePtr& addr() const  { return _addr; }
 116   BasicType type() const          { return _type; }
 117   bool is_oop() const             { return _type == T_OBJECT || _type == T_ARRAY; }
 118   bool is_raw() const             { return (_decorators & AS_RAW) != 0; }
 119   Node* raw_access() const        { return _raw_access; }
 120 
 121   void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
 122   virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.
 123 
 124   MemNode::MemOrd mem_node_mo() const;
 125   bool needs_cpu_membar() const;
 126 
 127   virtual PhaseGVN& gvn() const = 0;
 128   virtual bool is_parse_access() const { return false; }
 129   virtual bool is_opt_access() const { return false; }
 130 };
 131 
 132 // C2Access for parse time calls to the BarrierSetC2 backend.
 133 class C2ParseAccess: public C2Access {
 134 protected:
 135   GraphKit*         _kit;
 136 
 137   void* barrier_set_state() const;
 138 
 139 public:
 140   C2ParseAccess(GraphKit* kit, DecoratorSet decorators,
 141                 BasicType type, Node* base, C2AccessValuePtr& addr) :
 142     C2Access(decorators, type, base, addr),
 143     _kit(kit) {
 144     fixup_decorators();
 145   }
 146 
 147   GraphKit* kit() const           { return _kit; }
 148 
 149   template <typename T>
 150   T barrier_set_state_as() const {
 151     return reinterpret_cast<T>(barrier_set_state());
 152   }
 153 
 154   virtual PhaseGVN& gvn() const;
 155   virtual bool is_parse_access() const { return true; }
 156 };
 157 
 158 // This class wraps a bunch of context parameters thare are passed around in the
 159 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
 160 class C2AtomicParseAccess: public C2ParseAccess {
 161   Node* _memory;
 162   uint  _alias_idx;
 163   bool  _needs_pinning;
 164 
 165 public:
 166   C2AtomicParseAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
 167                  Node* base, C2AccessValuePtr& addr, uint alias_idx) :
 168     C2ParseAccess(kit, decorators, type, base, addr),
 169     _memory(NULL),
 170     _alias_idx(alias_idx),
 171     _needs_pinning(true) {}
 172 
 173   // Set the memory node based on the current memory slice.
 174   virtual void set_memory();
 175 
 176   Node* memory() const       { return _memory; }
 177   uint alias_idx() const     { return _alias_idx; }
 178   bool needs_pinning() const { return _needs_pinning; }
 179 
 180   void set_needs_pinning(bool value)    { _needs_pinning = value; }
 181 };
 182 
 183 // C2Access for optimization time calls to the BarrierSetC2 backend.
 184 class C2OptAccess: public C2Access {
 185   PhaseGVN& _gvn;
 186   MergeMemNode* _mem;
 187   Node* _ctl;
 188 
 189 public:
 190   C2OptAccess(PhaseGVN& gvn, Node* ctl, MergeMemNode* mem, DecoratorSet decorators,
 191               BasicType type, Node* base, C2AccessValuePtr& addr) :
 192     C2Access(decorators, type, base, addr),
 193     _gvn(gvn), _mem(mem), _ctl(ctl) {
 194     fixup_decorators();
 195   }
 196 
 197 
 198   MergeMemNode* mem() const { return _mem; }
 199   Node* ctl() const { return _ctl; }
 200   // void set_mem(Node* mem) { _mem = mem; }
 201   void set_ctl(Node* ctl) { _ctl = ctl; }
 202 
 203   virtual PhaseGVN& gvn() const { return _gvn; }
 204   virtual bool is_opt_access() const { return true; }
 205 };
 206 
 207 
 208 // This is the top-level class for the backend of the Access API in C2.
 209 // The top-level class is responsible for performing raw accesses. The
 210 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle
 211 // barriers into the accesses.
 212 class BarrierSetC2: public CHeapObj<mtGC> {
 213 protected:
 214   virtual void resolve_address(C2Access& access) const;
 215   virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
 216   virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;
 217 
 218   virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 219                                                Node* new_val, const Type* val_type) const;
 220   virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 221                                                 Node* new_val, const Type* value_type) const;
 222   virtual Node* atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
 223   virtual Node* atomic_add_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const;
 224   void pin_atomic_op(C2AtomicParseAccess& access) const;
 225 
 226 public:
 227   // This is the entry-point for the backend to perform accesses through the Access API.
 228   virtual Node* store_at(C2Access& access, C2AccessValue& val) const;
 229   virtual Node* load_at(C2Access& access, const Type* val_type) const;
 230 
 231   virtual Node* atomic_cmpxchg_val_at(C2AtomicParseAccess& access, Node* expected_val,
 232                                       Node* new_val, const Type* val_type) const;
 233   virtual Node* atomic_cmpxchg_bool_at(C2AtomicParseAccess& access, Node* expected_val,
 234                                        Node* new_val, const Type* val_type) const;
 235   virtual Node* atomic_xchg_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const;
 236   virtual Node* atomic_add_at(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const;
 237 
 238   virtual void clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const;
 239 
 240   virtual Node* resolve(GraphKit* kit, Node* n, DecoratorSet decorators) const { return n; }
 241 
 242   virtual Node* obj_allocate(PhaseMacroExpand* macro, Node* ctrl, Node* mem, Node* toobig_false, Node* size_in_bytes,
 243                              Node*& i_o, Node*& needgc_ctrl,
 244                              Node*& fast_oop_ctrl, Node*& fast_oop_rawmem,
 245                              intx prefetch_lines) const;
 246 
 247   // These are general helper methods used by C2
 248   enum ArrayCopyPhase {
 249     Parsing,
 250     Optimization,
 251     Expansion
 252   };
 253   virtual bool array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const { return false; }
 254   virtual void clone_barrier_at_expansion(ArrayCopyNode* ac, Node* call, PhaseIterGVN& igvn) const;
 255 
 256   // Support for GC barriers emitted during parsing
 257   virtual bool has_load_barriers() const { return false; }
 258   virtual bool is_gc_barrier_node(Node* node) const { return false; }
 259   virtual Node* step_over_gc_barrier(Node* c) const { return c; }
 260 
 261   // Support for macro expanded GC barriers
 262   virtual void register_potential_barrier_node(Node* node) const { }
 263   virtual void unregister_potential_barrier_node(Node* node) const { }
 264   virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { }
 265   virtual void enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {}
 266   virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {}
 267   virtual void add_users_to_worklist(Unique_Node_List* worklist) const {}
 268 
 269   // Allow barrier sets to have shared state that is preserved across a compilation unit.
 270   // This could for example comprise macro nodes to be expanded during macro expansion.
 271   virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; }
 272   // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
 273   // expanded later, then now is the time to do so.
 274   virtual bool expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
 275   virtual void verify_gc_barriers(bool post_parse) const {}
 276 };
 277 
 278 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP