1 /*
   2  * Copyright (c) 2001, 2013, 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_VM_OPTO_GRAPHKIT_HPP
  26 #define SHARE_VM_OPTO_GRAPHKIT_HPP
  27 
  28 #include "ci/ciEnv.hpp"
  29 #include "ci/ciMethodData.hpp"
  30 #include "opto/addnode.hpp"
  31 #include "opto/callnode.hpp"
  32 #include "opto/cfgnode.hpp"
  33 #include "opto/compile.hpp"
  34 #include "opto/divnode.hpp"
  35 #include "opto/mulnode.hpp"
  36 #include "opto/phaseX.hpp"
  37 #include "opto/subnode.hpp"
  38 #include "opto/type.hpp"
  39 #include "runtime/deoptimization.hpp"
  40 
  41 class FastLockNode;
  42 class FastUnlockNode;
  43 class IdealKit;
  44 class LibraryCallKit;
  45 class Parse;
  46 class RootNode;
  47 
  48 //-----------------------------------------------------------------------------
  49 //----------------------------GraphKit-----------------------------------------
  50 // Toolkit for building the common sorts of subgraphs.
  51 // Does not know about bytecode parsing or type-flow results.
  52 // It is able to create graphs implementing the semantics of most
  53 // or all bytecodes, so that it can expand intrinsics and calls.
  54 // It may depend on JVMState structure, but it must not depend
  55 // on specific bytecode streams.
  56 class GraphKit : public Phase {
  57   friend class PreserveJVMState;
  58 
  59  protected:
  60   ciEnv*            _env;       // Compilation environment
  61   PhaseGVN         &_gvn;       // Some optimizations while parsing
  62   SafePointNode*    _map;       // Parser map from JVM to Nodes
  63   SafePointNode*    _exceptions;// Parser map(s) for exception state(s)
  64   int               _bci;       // JVM Bytecode Pointer
  65   ciMethod*         _method;    // JVM Current Method
  66 
  67  private:
  68   int               _sp;        // JVM Expression Stack Pointer; don't modify directly!
  69 
  70  private:
  71   SafePointNode*     map_not_null() const {
  72     assert(_map != NULL, "must call stopped() to test for reset compiler map");
  73     return _map;
  74   }
  75 
  76  public:
  77   GraphKit();                   // empty constructor
  78   GraphKit(JVMState* jvms);     // the JVM state on which to operate
  79 
  80 #ifdef ASSERT
  81   ~GraphKit() {
  82     assert(!has_exceptions(), "user must call transfer_exceptions_into_jvms");
  83   }
  84 #endif
  85 
  86   virtual Parse*          is_Parse()          const { return NULL; }
  87   virtual LibraryCallKit* is_LibraryCallKit() const { return NULL; }
  88 
  89   ciEnv*        env()           const { return _env; }
  90   PhaseGVN&     gvn()           const { return _gvn; }
  91 
  92   void record_for_igvn(Node* n) const { C->record_for_igvn(n); }  // delegate to Compile
  93 
  94   // Handy well-known nodes:
  95   Node*         null()          const { return zerocon(T_OBJECT); }
  96   Node*         top()           const { return C->top(); }
  97   RootNode*     root()          const { return C->root(); }
  98 
  99   // Create or find a constant node
 100   Node* intcon(jint con)        const { return _gvn.intcon(con); }
 101   Node* longcon(jlong con)      const { return _gvn.longcon(con); }
 102   Node* makecon(const Type *t)  const { return _gvn.makecon(t); }
 103   Node* zerocon(BasicType bt)   const { return _gvn.zerocon(bt); }
 104   // (See also macro MakeConX in type.hpp, which uses intcon or longcon.)
 105 
 106   // Helper for byte_map_base
 107   Node* byte_map_base_node() {
 108     // Get base of card map
 109     CardTableModRefBS* ct = (CardTableModRefBS*)(Universe::heap()->barrier_set());
 110     assert(sizeof(*ct->byte_map_base) == sizeof(jbyte), "adjust users of this code");
 111     if (ct->byte_map_base != NULL) {
 112       return makecon(TypeRawPtr::make((address)ct->byte_map_base));
 113     } else {
 114       return null();
 115     }
 116   }
 117 
 118   jint  find_int_con(Node* n, jint value_if_unknown) {
 119     return _gvn.find_int_con(n, value_if_unknown);
 120   }
 121   jlong find_long_con(Node* n, jlong value_if_unknown) {
 122     return _gvn.find_long_con(n, value_if_unknown);
 123   }
 124   // (See also macro find_intptr_t_con in type.hpp, which uses one of these.)
 125 
 126   // JVM State accessors:
 127   // Parser mapping from JVM indices into Nodes.
 128   // Low slots are accessed by the StartNode::enum.
 129   // Then come the locals at StartNode::Parms to StartNode::Parms+max_locals();
 130   // Then come JVM stack slots.
 131   // Finally come the monitors, if any.
 132   // See layout accessors in class JVMState.
 133 
 134   SafePointNode*     map()      const { return _map; }
 135   bool               has_exceptions() const { return _exceptions != NULL; }
 136   JVMState*          jvms()     const { return map_not_null()->_jvms; }
 137   int                sp()       const { return _sp; }
 138   int                bci()      const { return _bci; }
 139   Bytecodes::Code    java_bc()  const;
 140   ciMethod*          method()   const { return _method; }
 141 
 142   void set_jvms(JVMState* jvms)       { set_map(jvms->map());
 143                                         assert(jvms == this->jvms(), "sanity");
 144                                         _sp = jvms->sp();
 145                                         _bci = jvms->bci();
 146                                         _method = jvms->has_method() ? jvms->method() : NULL; }
 147   void set_map(SafePointNode* m)      { _map = m; debug_only(verify_map()); }
 148   void set_sp(int sp)                 { assert(sp >= 0, err_msg_res("sp must be non-negative: %d", sp)); _sp = sp; }
 149   void clean_stack(int from_sp); // clear garbage beyond from_sp to top
 150 
 151   void inc_sp(int i)                  { set_sp(sp() + i); }
 152   void dec_sp(int i)                  { set_sp(sp() - i); }
 153   void set_bci(int bci)               { _bci = bci; }
 154 
 155   // Make sure jvms has current bci & sp.
 156   JVMState* sync_jvms() const;
 157   JVMState* sync_jvms_for_reexecute();
 158 
 159 #ifdef ASSERT
 160   // Make sure JVMS has an updated copy of bci and sp.
 161   // Also sanity-check method, depth, and monitor depth.
 162   bool jvms_in_sync() const;
 163 
 164   // Make sure the map looks OK.
 165   void verify_map() const;
 166 
 167   // Make sure a proposed exception state looks OK.
 168   static void verify_exception_state(SafePointNode* ex_map);
 169 #endif
 170 
 171   // Clone the existing map state.  (Implements PreserveJVMState.)
 172   SafePointNode* clone_map();
 173 
 174   // Set the map to a clone of the given one.
 175   void set_map_clone(SafePointNode* m);
 176 
 177   // Tell if the compilation is failing.
 178   bool failing() const { return C->failing(); }
 179 
 180   // Set _map to NULL, signalling a stop to further bytecode execution.
 181   // Preserve the map intact for future use, and return it back to the caller.
 182   SafePointNode* stop() { SafePointNode* m = map(); set_map(NULL); return m; }
 183 
 184   // Stop, but first smash the map's inputs to NULL, to mark it dead.
 185   void stop_and_kill_map();
 186 
 187   // Tell if _map is NULL, or control is top.
 188   bool stopped();
 189 
 190   // Tell if this method or any caller method has exception handlers.
 191   bool has_ex_handler();
 192 
 193   // Save an exception without blowing stack contents or other JVM state.
 194   // (The extra pointer is stuck with add_req on the map, beyond the JVMS.)
 195   static void set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop);
 196 
 197   // Recover a saved exception from its map.
 198   static Node* saved_ex_oop(SafePointNode* ex_map);
 199 
 200   // Recover a saved exception from its map, and remove it from the map.
 201   static Node* clear_saved_ex_oop(SafePointNode* ex_map);
 202 
 203 #ifdef ASSERT
 204   // Recover a saved exception from its map, and remove it from the map.
 205   static bool has_saved_ex_oop(SafePointNode* ex_map);
 206 #endif
 207 
 208   // Push an exception in the canonical position for handlers (stack(0)).
 209   void push_ex_oop(Node* ex_oop) {
 210     ensure_stack(1);  // ensure room to push the exception
 211     set_stack(0, ex_oop);
 212     set_sp(1);
 213     clean_stack(1);
 214   }
 215 
 216   // Detach and return an exception state.
 217   SafePointNode* pop_exception_state() {
 218     SafePointNode* ex_map = _exceptions;
 219     if (ex_map != NULL) {
 220       _exceptions = ex_map->next_exception();
 221       ex_map->set_next_exception(NULL);
 222       debug_only(verify_exception_state(ex_map));
 223     }
 224     return ex_map;
 225   }
 226 
 227   // Add an exception, using the given JVM state, without commoning.
 228   void push_exception_state(SafePointNode* ex_map) {
 229     debug_only(verify_exception_state(ex_map));
 230     ex_map->set_next_exception(_exceptions);
 231     _exceptions = ex_map;
 232   }
 233 
 234   // Turn the current JVM state into an exception state, appending the ex_oop.
 235   SafePointNode* make_exception_state(Node* ex_oop);
 236 
 237   // Add an exception, using the given JVM state.
 238   // Combine all exceptions with a common exception type into a single state.
 239   // (This is done via combine_exception_states.)
 240   void add_exception_state(SafePointNode* ex_map);
 241 
 242   // Combine all exceptions of any sort whatever into a single master state.
 243   SafePointNode* combine_and_pop_all_exception_states() {
 244     if (_exceptions == NULL)  return NULL;
 245     SafePointNode* phi_map = pop_exception_state();
 246     SafePointNode* ex_map;
 247     while ((ex_map = pop_exception_state()) != NULL) {
 248       combine_exception_states(ex_map, phi_map);
 249     }
 250     return phi_map;
 251   }
 252 
 253   // Combine the two exception states, building phis as necessary.
 254   // The second argument is updated to include contributions from the first.
 255   void combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map);
 256 
 257   // Reset the map to the given state.  If there are any half-finished phis
 258   // in it (created by combine_exception_states), transform them now.
 259   // Returns the exception oop.  (Caller must call push_ex_oop if required.)
 260   Node* use_exception_state(SafePointNode* ex_map);
 261 
 262   // Collect exceptions from a given JVM state into my exception list.
 263   void add_exception_states_from(JVMState* jvms);
 264 
 265   // Collect all raised exceptions into the current JVM state.
 266   // Clear the current exception list and map, returns the combined states.
 267   JVMState* transfer_exceptions_into_jvms();
 268 
 269   // Helper to throw a built-in exception.
 270   // Range checks take the offending index.
 271   // Cast and array store checks take the offending class.
 272   // Others do not take the optional argument.
 273   // The JVMS must allow the bytecode to be re-executed
 274   // via an uncommon trap.
 275   void builtin_throw(Deoptimization::DeoptReason reason, Node* arg = NULL);
 276 
 277   // Helper to check the JavaThread::_should_post_on_exceptions flag
 278   // and branch to an uncommon_trap if it is true (with the specified reason and must_throw)
 279   void uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
 280                                                   bool must_throw) ;
 281 
 282   // Helper Functions for adding debug information
 283   void kill_dead_locals();
 284 #ifdef ASSERT
 285   bool dead_locals_are_killed();
 286 #endif
 287   // The call may deoptimize.  Supply required JVM state as debug info.
 288   // If must_throw is true, the call is guaranteed not to return normally.
 289   void add_safepoint_edges(SafePointNode* call,
 290                            bool must_throw = false);
 291 
 292   // How many stack inputs does the current BC consume?
 293   // And, how does the stack change after the bytecode?
 294   // Returns false if unknown.
 295   bool compute_stack_effects(int& inputs, int& depth);
 296 
 297   // Add a fixed offset to a pointer
 298   Node* basic_plus_adr(Node* base, Node* ptr, intptr_t offset) {
 299     return basic_plus_adr(base, ptr, MakeConX(offset));
 300   }
 301   Node* basic_plus_adr(Node* base, intptr_t offset) {
 302     return basic_plus_adr(base, base, MakeConX(offset));
 303   }
 304   // Add a variable offset to a pointer
 305   Node* basic_plus_adr(Node* base, Node* offset) {
 306     return basic_plus_adr(base, base, offset);
 307   }
 308   Node* basic_plus_adr(Node* base, Node* ptr, Node* offset);
 309 
 310 
 311   // Some convenient shortcuts for common nodes
 312   Node* IfTrue(IfNode* iff)                   { return _gvn.transform(new (C) IfTrueNode(iff));      }
 313   Node* IfFalse(IfNode* iff)                  { return _gvn.transform(new (C) IfFalseNode(iff));     }
 314 
 315   Node* AddI(Node* l, Node* r)                { return _gvn.transform(new (C) AddINode(l, r));       }
 316   Node* SubI(Node* l, Node* r)                { return _gvn.transform(new (C) SubINode(l, r));       }
 317   Node* MulI(Node* l, Node* r)                { return _gvn.transform(new (C) MulINode(l, r));       }
 318   Node* DivI(Node* ctl, Node* l, Node* r)     { return _gvn.transform(new (C) DivINode(ctl, l, r));  }
 319 
 320   Node* AndI(Node* l, Node* r)                { return _gvn.transform(new (C) AndINode(l, r));       }
 321   Node* OrI(Node* l, Node* r)                 { return _gvn.transform(new (C) OrINode(l, r));        }
 322   Node* XorI(Node* l, Node* r)                { return _gvn.transform(new (C) XorINode(l, r));       }
 323 
 324   Node* MaxI(Node* l, Node* r)                { return _gvn.transform(new (C) MaxINode(l, r));       }
 325   Node* MinI(Node* l, Node* r)                { return _gvn.transform(new (C) MinINode(l, r));       }
 326 
 327   Node* LShiftI(Node* l, Node* r)             { return _gvn.transform(new (C) LShiftINode(l, r));    }
 328   Node* RShiftI(Node* l, Node* r)             { return _gvn.transform(new (C) RShiftINode(l, r));    }
 329   Node* URShiftI(Node* l, Node* r)            { return _gvn.transform(new (C) URShiftINode(l, r));   }
 330 
 331   Node* CmpI(Node* l, Node* r)                { return _gvn.transform(new (C) CmpINode(l, r));       }
 332   Node* CmpL(Node* l, Node* r)                { return _gvn.transform(new (C) CmpLNode(l, r));       }
 333   Node* CmpP(Node* l, Node* r)                { return _gvn.transform(new (C) CmpPNode(l, r));       }
 334   Node* Bool(Node* cmp, BoolTest::mask relop) { return _gvn.transform(new (C) BoolNode(cmp, relop)); }
 335 
 336   Node* AddP(Node* b, Node* a, Node* o)       { return _gvn.transform(new (C) AddPNode(b, a, o));    }
 337 
 338   // Convert between int and long, and size_t.
 339   // (See macros ConvI2X, etc., in type.hpp for ConvI2X, etc.)
 340   Node* ConvI2L(Node* offset);
 341   Node* ConvI2UL(Node* offset);
 342   Node* ConvL2I(Node* offset);
 343   // Find out the klass of an object.
 344   Node* load_object_klass(Node* object);
 345   // Find out the length of an array.
 346   Node* load_array_length(Node* array);
 347 
 348 
 349   // Helper function to do a NULL pointer check or ZERO check based on type.
 350   // Throw an exception if a given value is null.
 351   // Return the value cast to not-null.
 352   // Be clever about equivalent dominating null checks.
 353   Node* null_check_common(Node* value, BasicType type,
 354                           bool assert_null = false,
 355                           Node* *null_control = NULL,
 356                           bool speculative = false);
 357   Node* null_check(Node* value, BasicType type = T_OBJECT) {
 358     return null_check_common(value, type, false, NULL, !_gvn.type(value)->speculative_maybe_null());
 359   }
 360   Node* null_check_receiver() {
 361     assert(argument(0)->bottom_type()->isa_ptr(), "must be");
 362     return null_check(argument(0));
 363   }
 364   Node* zero_check_int(Node* value) {
 365     assert(value->bottom_type()->basic_type() == T_INT,
 366         err_msg_res("wrong type: %s", type2name(value->bottom_type()->basic_type())));
 367     return null_check_common(value, T_INT);
 368   }
 369   Node* zero_check_long(Node* value) {
 370     assert(value->bottom_type()->basic_type() == T_LONG,
 371         err_msg_res("wrong type: %s", type2name(value->bottom_type()->basic_type())));
 372     return null_check_common(value, T_LONG);
 373   }
 374   // Throw an uncommon trap if a given value is __not__ null.
 375   // Return the value cast to null, and be clever about dominating checks.
 376   Node* null_assert(Node* value, BasicType type = T_OBJECT) {
 377     return null_check_common(value, type, true);
 378   }
 379 
 380   // Null check oop.  Return null-path control into (*null_control).
 381   // Return a cast-not-null node which depends on the not-null control.
 382   // If never_see_null, use an uncommon trap (*null_control sees a top).
 383   // The cast is not valid along the null path; keep a copy of the original.
 384   // If safe_for_replace, then we can replace the value with the cast
 385   // in the parsing map (the cast is guaranteed to dominate the map)
 386   Node* null_check_oop(Node* value, Node* *null_control,
 387                        bool never_see_null = false,
 388                        bool safe_for_replace = false,
 389                        bool speculative = false);
 390 
 391   // Check the null_seen bit.
 392   bool seems_never_null(Node* obj, ciProfileData* data, bool& speculating);
 393 
 394   // Check for unique class for receiver at call
 395   ciKlass* profile_has_unique_klass() {
 396     ciCallProfile profile = method()->call_profile_at_bci(bci());
 397     if (profile.count() >= 0 &&         // no cast failures here
 398         profile.has_receiver(0) &&
 399         profile.morphism() == 1) {
 400       return profile.receiver(0);
 401     }
 402     return NULL;
 403   }
 404 
 405   // record type from profiling with the type system
 406   Node* record_profile_for_speculation(Node* n, ciKlass* exact_kls, bool maybe_null);
 407   void record_profiled_arguments_for_speculation(ciMethod* dest_method, Bytecodes::Code bc);
 408   void record_profiled_parameters_for_speculation();
 409   void record_profiled_return_for_speculation();
 410   Node* record_profiled_receiver_for_speculation(Node* n);
 411 
 412   // Use the type profile to narrow an object type.
 413   Node* maybe_cast_profiled_receiver(Node* not_null_obj,
 414                                      ciKlass* require_klass,
 415                                      ciKlass* spec,
 416                                      bool safe_for_replace);
 417 
 418   // Cast obj to type and emit guard unless we had too many traps here already
 419   Node* maybe_cast_profiled_obj(Node* obj,
 420                                 ciKlass* type,
 421                                 bool not_null = false);
 422 
 423   // Cast obj to not-null on this path
 424   Node* cast_not_null(Node* obj, bool do_replace_in_map = true);
 425   // Replace all occurrences of one node by another.
 426   void replace_in_map(Node* old, Node* neww);
 427 
 428   void  push(Node* n)     { map_not_null();        _map->set_stack(_map->_jvms,   _sp++        , n); }
 429   Node* pop()             { map_not_null(); return _map->stack(    _map->_jvms, --_sp             ); }
 430   Node* peek(int off = 0) { map_not_null(); return _map->stack(    _map->_jvms,   _sp - off - 1   ); }
 431 
 432   void push_pair(Node* ldval) {
 433     push(ldval);
 434     push(top());  // the halfword is merely a placeholder
 435   }
 436   void push_pair_local(int i) {
 437     // longs are stored in locals in "push" order
 438     push(  local(i+0) );  // the real value
 439     assert(local(i+1) == top(), "");
 440     push(top());  // halfword placeholder
 441   }
 442   Node* pop_pair() {
 443     // the second half is pushed last & popped first; it contains exactly nothing
 444     Node* halfword = pop();
 445     assert(halfword == top(), "");
 446     // the long bits are pushed first & popped last:
 447     return pop();
 448   }
 449   void set_pair_local(int i, Node* lval) {
 450     // longs are stored in locals as a value/half pair (like doubles)
 451     set_local(i+0, lval);
 452     set_local(i+1, top());
 453   }
 454 
 455   // Push the node, which may be zero, one, or two words.
 456   void push_node(BasicType n_type, Node* n) {
 457     int n_size = type2size[n_type];
 458     if      (n_size == 1)  push(      n );  // T_INT, ...
 459     else if (n_size == 2)  push_pair( n );  // T_DOUBLE, T_LONG
 460     else                   { assert(n_size == 0, "must be T_VOID"); }
 461   }
 462 
 463   Node* pop_node(BasicType n_type) {
 464     int n_size = type2size[n_type];
 465     if      (n_size == 1)  return pop();
 466     else if (n_size == 2)  return pop_pair();
 467     else                   return NULL;
 468   }
 469 
 470   Node* control()               const { return map_not_null()->control(); }
 471   Node* i_o()                   const { return map_not_null()->i_o(); }
 472   Node* returnadr()             const { return map_not_null()->returnadr(); }
 473   Node* frameptr()              const { return map_not_null()->frameptr(); }
 474   Node* local(uint idx)         const { map_not_null(); return _map->local(      _map->_jvms, idx); }
 475   Node* stack(uint idx)         const { map_not_null(); return _map->stack(      _map->_jvms, idx); }
 476   Node* argument(uint idx)      const { map_not_null(); return _map->argument(   _map->_jvms, idx); }
 477   Node* monitor_box(uint idx)   const { map_not_null(); return _map->monitor_box(_map->_jvms, idx); }
 478   Node* monitor_obj(uint idx)   const { map_not_null(); return _map->monitor_obj(_map->_jvms, idx); }
 479 
 480   void set_control  (Node* c)         { map_not_null()->set_control(c); }
 481   void set_i_o      (Node* c)         { map_not_null()->set_i_o(c); }
 482   void set_local(uint idx, Node* c)   { map_not_null(); _map->set_local(   _map->_jvms, idx, c); }
 483   void set_stack(uint idx, Node* c)   { map_not_null(); _map->set_stack(   _map->_jvms, idx, c); }
 484   void set_argument(uint idx, Node* c){ map_not_null(); _map->set_argument(_map->_jvms, idx, c); }
 485   void ensure_stack(uint stk_size)    { map_not_null(); _map->ensure_stack(_map->_jvms, stk_size); }
 486 
 487   // Access unaliased memory
 488   Node* memory(uint alias_idx);
 489   Node* memory(const TypePtr *tp) { return memory(C->get_alias_index(tp)); }
 490   Node* memory(Node* adr) { return memory(_gvn.type(adr)->is_ptr()); }
 491 
 492   // Access immutable memory
 493   Node* immutable_memory() { return C->immutable_memory(); }
 494 
 495   // Set unaliased memory
 496   void set_memory(Node* c, uint alias_idx) { merged_memory()->set_memory_at(alias_idx, c); }
 497   void set_memory(Node* c, const TypePtr *tp) { set_memory(c,C->get_alias_index(tp)); }
 498   void set_memory(Node* c, Node* adr) { set_memory(c,_gvn.type(adr)->is_ptr()); }
 499 
 500   // Get the entire memory state (probably a MergeMemNode), and reset it
 501   // (The resetting prevents somebody from using the dangling Node pointer.)
 502   Node* reset_memory();
 503 
 504   // Get the entire memory state, asserted to be a MergeMemNode.
 505   MergeMemNode* merged_memory() {
 506     Node* mem = map_not_null()->memory();
 507     assert(mem->is_MergeMem(), "parse memory is always pre-split");
 508     return mem->as_MergeMem();
 509   }
 510 
 511   // Set the entire memory state; produce a new MergeMemNode.
 512   void set_all_memory(Node* newmem);
 513 
 514   // Create a memory projection from the call, then set_all_memory.
 515   void set_all_memory_call(Node* call, bool separate_io_proj = false);
 516 
 517   // Create a LoadNode, reading from the parser's memory state.
 518   // (Note:  require_atomic_access is useful only with T_LONG.)
 519   //
 520   // We choose the unordered semantics by default because we have
 521   // adapted the `do_put_xxx' and `do_get_xxx' procedures for the case
 522   // of volatile fields.
 523   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,
 524                   MemNode::MemOrd mo, bool require_atomic_access = false) {
 525     // This version computes alias_index from bottom_type
 526     return make_load(ctl, adr, t, bt, adr->bottom_type()->is_ptr(),
 527                      mo, require_atomic_access);
 528   }
 529   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt, const TypePtr* adr_type,
 530                   MemNode::MemOrd mo, bool require_atomic_access = false) {
 531     // This version computes alias_index from an address type
 532     assert(adr_type != NULL, "use other make_load factory");
 533     return make_load(ctl, adr, t, bt, C->get_alias_index(adr_type),
 534                      mo, require_atomic_access);
 535   }
 536   // This is the base version which is given an alias index.
 537   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt, int adr_idx,
 538                   MemNode::MemOrd mo, bool require_atomic_access = false);
 539 
 540   // Create & transform a StoreNode and store the effect into the
 541   // parser's memory state.
 542   //
 543   // We must ensure that stores of object references will be visible
 544   // only after the object's initialization. So the clients of this
 545   // procedure must indicate that the store requires `release'
 546   // semantics, if the stored value is an object reference that might
 547   // point to a new object and may become externally visible.
 548   Node* store_to_memory(Node* ctl, Node* adr, Node* val, BasicType bt,
 549                         const TypePtr* adr_type,
 550                         MemNode::MemOrd mo,
 551                         bool require_atomic_access = false) {
 552     // This version computes alias_index from an address type
 553     assert(adr_type != NULL, "use other store_to_memory factory");
 554     return store_to_memory(ctl, adr, val, bt,
 555                            C->get_alias_index(adr_type),
 556                            mo, require_atomic_access);
 557   }
 558   // This is the base version which is given alias index
 559   // Return the new StoreXNode
 560   Node* store_to_memory(Node* ctl, Node* adr, Node* val, BasicType bt,
 561                         int adr_idx,
 562                         MemNode::MemOrd,
 563                         bool require_atomic_access = false);
 564 
 565 
 566   // All in one pre-barrier, store, post_barrier
 567   // Insert a write-barrier'd store.  This is to let generational GC
 568   // work; we have to flag all oop-stores before the next GC point.
 569   //
 570   // It comes in 3 flavors of store to an object, array, or unknown.
 571   // We use precise card marks for arrays to avoid scanning the entire
 572   // array. We use imprecise for object. We use precise for unknown
 573   // since we don't know if we have an array or and object or even
 574   // where the object starts.
 575   //
 576   // If val==NULL, it is taken to be a completely unknown value. QQQ
 577 
 578   Node* store_oop(Node* ctl,
 579                   Node* obj,   // containing obj
 580                   Node* adr,   // actual adress to store val at
 581                   const TypePtr* adr_type,
 582                   Node* val,
 583                   const TypeOopPtr* val_type,
 584                   BasicType bt,
 585                   bool use_precise,
 586                   MemNode::MemOrd mo);
 587 
 588   Node* store_oop_to_object(Node* ctl,
 589                             Node* obj,   // containing obj
 590                             Node* adr,   // actual adress to store val at
 591                             const TypePtr* adr_type,
 592                             Node* val,
 593                             const TypeOopPtr* val_type,
 594                             BasicType bt,
 595                             MemNode::MemOrd mo) {
 596     return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, false, mo);
 597   }
 598 
 599   Node* store_oop_to_array(Node* ctl,
 600                            Node* obj,   // containing obj
 601                            Node* adr,   // actual adress to store val at
 602                            const TypePtr* adr_type,
 603                            Node* val,
 604                            const TypeOopPtr* val_type,
 605                            BasicType bt,
 606                            MemNode::MemOrd mo) {
 607     return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, true, mo);
 608   }
 609 
 610   // Could be an array or object we don't know at compile time (unsafe ref.)
 611   Node* store_oop_to_unknown(Node* ctl,
 612                              Node* obj,   // containing obj
 613                              Node* adr,   // actual adress to store val at
 614                              const TypePtr* adr_type,
 615                              Node* val,
 616                              BasicType bt,
 617                              MemNode::MemOrd mo);
 618 
 619   // For the few case where the barriers need special help
 620   void pre_barrier(bool do_load, Node* ctl,
 621                    Node* obj, Node* adr, uint adr_idx, Node* val, const TypeOopPtr* val_type,
 622                    Node* pre_val,
 623                    BasicType bt);
 624 
 625   void post_barrier(Node* ctl, Node* store, Node* obj, Node* adr, uint adr_idx,
 626                     Node* val, BasicType bt, bool use_precise);
 627 
 628   // Return addressing for an array element.
 629   Node* array_element_address(Node* ary, Node* idx, BasicType elembt,
 630                               // Optional constraint on the array size:
 631                               const TypeInt* sizetype = NULL);
 632 
 633   // Return a load of array element at idx.
 634   Node* load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype);
 635 
 636   //---------------- Dtrace support --------------------
 637   void make_dtrace_method_entry_exit(ciMethod* method, bool is_entry);
 638   void make_dtrace_method_entry(ciMethod* method) {
 639     make_dtrace_method_entry_exit(method, true);
 640   }
 641   void make_dtrace_method_exit(ciMethod* method) {
 642     make_dtrace_method_entry_exit(method, false);
 643   }
 644 
 645   //--------------- stub generation -------------------
 646  public:
 647   void gen_stub(address C_function,
 648                 const char *name,
 649                 int is_fancy_jump,
 650                 bool pass_tls,
 651                 bool return_pc);
 652 
 653   //---------- help for generating calls --------------
 654 
 655   // Do a null check on the receiver as it would happen before the call to
 656   // callee (with all arguments still on the stack).
 657   Node* null_check_receiver_before_call(ciMethod* callee) {
 658     assert(!callee->is_static(), "must be a virtual method");
 659     const int nargs = callee->arg_size();
 660     inc_sp(nargs);
 661     Node* n = null_check_receiver();
 662     dec_sp(nargs);
 663     return n;
 664   }
 665 
 666   // Fill in argument edges for the call from argument(0), argument(1), ...
 667   // (The next step is to call set_edges_for_java_call.)
 668   void  set_arguments_for_java_call(CallJavaNode* call);
 669 
 670   // Fill in non-argument edges for the call.
 671   // Transform the call, and update the basics: control, i_o, memory.
 672   // (The next step is usually to call set_results_for_java_call.)
 673   void set_edges_for_java_call(CallJavaNode* call,
 674                                bool must_throw = false, bool separate_io_proj = false);
 675 
 676   // Finish up a java call that was started by set_edges_for_java_call.
 677   // Call add_exception on any throw arising from the call.
 678   // Return the call result (transformed).
 679   Node* set_results_for_java_call(CallJavaNode* call, bool separate_io_proj = false);
 680 
 681   // Similar to set_edges_for_java_call, but simplified for runtime calls.
 682   void  set_predefined_output_for_runtime_call(Node* call) {
 683     set_predefined_output_for_runtime_call(call, NULL, NULL);
 684   }
 685   void  set_predefined_output_for_runtime_call(Node* call,
 686                                                Node* keep_mem,
 687                                                const TypePtr* hook_mem);
 688   Node* set_predefined_input_for_runtime_call(SafePointNode* call);
 689 
 690   // Replace the call with the current state of the kit.  Requires
 691   // that the call was generated with separate io_projs so that
 692   // exceptional control flow can be handled properly.
 693   void replace_call(CallNode* call, Node* result);
 694 
 695   // helper functions for statistics
 696   void increment_counter(address counter_addr);   // increment a debug counter
 697   void increment_counter(Node*   counter_addr);   // increment a debug counter
 698 
 699   // Bail out to the interpreter right now
 700   // The optional klass is the one causing the trap.
 701   // The optional reason is debug information written to the compile log.
 702   // Optional must_throw is the same as with add_safepoint_edges.
 703   void uncommon_trap(int trap_request,
 704                      ciKlass* klass = NULL, const char* reason_string = NULL,
 705                      bool must_throw = false, bool keep_exact_action = false);
 706 
 707   // Shorthand, to avoid saying "Deoptimization::" so many times.
 708   void uncommon_trap(Deoptimization::DeoptReason reason,
 709                      Deoptimization::DeoptAction action,
 710                      ciKlass* klass = NULL, const char* reason_string = NULL,
 711                      bool must_throw = false, bool keep_exact_action = false) {
 712     uncommon_trap(Deoptimization::make_trap_request(reason, action),
 713                   klass, reason_string, must_throw, keep_exact_action);
 714   }
 715 
 716   // SP when bytecode needs to be reexecuted.
 717   virtual int reexecute_sp() { return sp(); }
 718 
 719   // Report if there were too many traps at the current method and bci.
 720   // Report if a trap was recorded, and/or PerMethodTrapLimit was exceeded.
 721   // If there is no MDO at all, report no trap unless told to assume it.
 722   bool too_many_traps(Deoptimization::DeoptReason reason) {
 723     return C->too_many_traps(method(), bci(), reason);
 724   }
 725 
 726   // Report if there were too many recompiles at the current method and bci.
 727   bool too_many_recompiles(Deoptimization::DeoptReason reason) {
 728     return C->too_many_recompiles(method(), bci(), reason);
 729   }
 730 
 731   // Returns the object (if any) which was created the moment before.
 732   Node* just_allocated_object(Node* current_control);
 733 
 734   static bool use_ReduceInitialCardMarks() {
 735     return (ReduceInitialCardMarks
 736             && Universe::heap()->can_elide_tlab_store_barriers());
 737   }
 738 
 739   // Sync Ideal and Graph kits.
 740   void sync_kit(IdealKit& ideal);
 741   void final_sync(IdealKit& ideal);
 742 
 743   // vanilla/CMS post barrier
 744   void write_barrier_post(Node *store, Node* obj,
 745                           Node* adr,  uint adr_idx, Node* val, bool use_precise);
 746 
 747   // Allow reordering of pre-barrier with oop store and/or post-barrier.
 748   // Used for load_store operations which loads old value.
 749   bool can_move_pre_barrier() const;
 750 
 751   // G1 pre/post barriers
 752   void g1_write_barrier_pre(bool do_load,
 753                             Node* obj,
 754                             Node* adr,
 755                             uint alias_idx,
 756                             Node* val,
 757                             const TypeOopPtr* val_type,
 758                             Node* pre_val,
 759                             BasicType bt);
 760 
 761   void g1_write_barrier_post(Node* store,
 762                              Node* obj,
 763                              Node* adr,
 764                              uint alias_idx,
 765                              Node* val,
 766                              BasicType bt,
 767                              bool use_precise);
 768   // Helper function for g1
 769   private:
 770   void g1_mark_card(IdealKit& ideal, Node* card_adr, Node* store, uint oop_alias_idx,
 771                     Node* index, Node* index_adr,
 772                     Node* buffer, const TypeFunc* tf);
 773 
 774   public:
 775   // Helper function to round double arguments before a call
 776   void round_double_arguments(ciMethod* dest_method);
 777   void round_double_result(ciMethod* dest_method);
 778 
 779   // rounding for strict float precision conformance
 780   Node* precision_rounding(Node* n);
 781 
 782   // rounding for strict double precision conformance
 783   Node* dprecision_rounding(Node* n);
 784 
 785   // rounding for non-strict double stores
 786   Node* dstore_rounding(Node* n);
 787 
 788   // Helper functions for fast/slow path codes
 789   Node* opt_iff(Node* region, Node* iff);
 790   Node* make_runtime_call(int flags,
 791                           const TypeFunc* call_type, address call_addr,
 792                           const char* call_name,
 793                           const TypePtr* adr_type, // NULL if no memory effects
 794                           Node* parm0 = NULL, Node* parm1 = NULL,
 795                           Node* parm2 = NULL, Node* parm3 = NULL,
 796                           Node* parm4 = NULL, Node* parm5 = NULL,
 797                           Node* parm6 = NULL, Node* parm7 = NULL);
 798   enum {  // flag values for make_runtime_call
 799     RC_NO_FP = 1,               // CallLeafNoFPNode
 800     RC_NO_IO = 2,               // do not hook IO edges
 801     RC_NO_LEAF = 4,             // CallStaticJavaNode
 802     RC_MUST_THROW = 8,          // flag passed to add_safepoint_edges
 803     RC_NARROW_MEM = 16,         // input memory is same as output
 804     RC_UNCOMMON = 32,           // freq. expected to be like uncommon trap
 805     RC_LEAF = 0                 // null value:  no flags set
 806   };
 807 
 808   // merge in all memory slices from new_mem, along the given path
 809   void merge_memory(Node* new_mem, Node* region, int new_path);
 810   void make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj);
 811 
 812   // Helper functions to build synchronizations
 813   int next_monitor();
 814   Node* insert_mem_bar(int opcode, Node* precedent = NULL);
 815   Node* insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent = NULL);
 816   // Optional 'precedent' is appended as an extra edge, to force ordering.
 817   FastLockNode* shared_lock(Node* obj);
 818   void shared_unlock(Node* box, Node* obj);
 819 
 820   // helper functions for the fast path/slow path idioms
 821   Node* fast_and_slow(Node* in, const Type *result_type, Node* null_result, IfNode* fast_test, Node* fast_result, address slow_call, const TypeFunc *slow_call_type, Node* slow_arg, Klass* ex_klass, Node* slow_result);
 822 
 823   // Generate an instance-of idiom.  Used by both the instance-of bytecode
 824   // and the reflective instance-of call.
 825   Node* gen_instanceof(Node *subobj, Node* superkls, bool safe_for_replace = false);
 826 
 827   // Generate a check-cast idiom.  Used by both the check-cast bytecode
 828   // and the array-store bytecode
 829   Node* gen_checkcast( Node *subobj, Node* superkls,
 830                        Node* *failure_control = NULL );
 831 
 832   // Generate a subtyping check.  Takes as input the subtype and supertype.
 833   // Returns 2 values: sets the default control() to the true path and
 834   // returns the false path.  Only reads from constant memory taken from the
 835   // default memory; does not write anything.  It also doesn't take in an
 836   // Object; if you wish to check an Object you need to load the Object's
 837   // class prior to coming here.
 838   Node* gen_subtype_check(Node* subklass, Node* superklass);
 839 
 840   // Static parse-time type checking logic for gen_subtype_check:
 841   enum { SSC_always_false, SSC_always_true, SSC_easy_test, SSC_full_test };
 842   int static_subtype_check(ciKlass* superk, ciKlass* subk);
 843 
 844   // Exact type check used for predicted calls and casts.
 845   // Rewrites (*casted_receiver) to be casted to the stronger type.
 846   // (Caller is responsible for doing replace_in_map.)
 847   Node* type_check_receiver(Node* receiver, ciKlass* klass, float prob,
 848                             Node* *casted_receiver);
 849 
 850   // implementation of object creation
 851   Node* set_output_for_allocation(AllocateNode* alloc,
 852                                   const TypeOopPtr* oop_type);
 853   Node* get_layout_helper(Node* klass_node, jint& constant_value);
 854   Node* new_instance(Node* klass_node,
 855                      Node* slow_test = NULL,
 856                      Node* *return_size_val = NULL);
 857   Node* new_array(Node* klass_node, Node* count_val, int nargs,
 858                   Node* *return_size_val = NULL);
 859 
 860   // java.lang.String helpers
 861   Node* load_String_offset(Node* ctrl, Node* str);
 862   Node* load_String_length(Node* ctrl, Node* str);
 863   Node* load_String_value(Node* ctrl, Node* str);
 864   void store_String_offset(Node* ctrl, Node* str, Node* value);
 865   void store_String_length(Node* ctrl, Node* str, Node* value);
 866   void store_String_value(Node* ctrl, Node* str, Node* value);
 867 
 868   // Handy for making control flow
 869   IfNode* create_and_map_if(Node* ctrl, Node* tst, float prob, float cnt) {
 870     IfNode* iff = new (C) IfNode(ctrl, tst, prob, cnt);// New IfNode's
 871     _gvn.set_type(iff, iff->Value(&_gvn)); // Value may be known at parse-time
 872     // Place 'if' on worklist if it will be in graph
 873     if (!tst->is_Con())  record_for_igvn(iff);     // Range-check and Null-check removal is later
 874     return iff;
 875   }
 876 
 877   IfNode* create_and_xform_if(Node* ctrl, Node* tst, float prob, float cnt) {
 878     IfNode* iff = new (C) IfNode(ctrl, tst, prob, cnt);// New IfNode's
 879     _gvn.transform(iff);                           // Value may be known at parse-time
 880     // Place 'if' on worklist if it will be in graph
 881     if (!tst->is_Con())  record_for_igvn(iff);     // Range-check and Null-check removal is later
 882     return iff;
 883   }
 884 
 885   // Insert a loop predicate into the graph
 886   void add_predicate(int nargs = 0);
 887   void add_predicate_impl(Deoptimization::DeoptReason reason, int nargs);
 888 
 889   // Produce new array node of stable type
 890   Node* cast_array_to_stable(Node* ary, const TypeAryPtr* ary_type);
 891 };
 892 
 893 // Helper class to support building of control flow branches. Upon
 894 // creation the map and sp at bci are cloned and restored upon de-
 895 // struction. Typical use:
 896 //
 897 // { PreserveJVMState pjvms(this);
 898 //   // code of new branch
 899 // }
 900 // // here the JVM state at bci is established
 901 
 902 class PreserveJVMState: public StackObj {
 903  protected:
 904   GraphKit*      _kit;
 905 #ifdef ASSERT
 906   int            _block;  // PO of current block, if a Parse
 907   int            _bci;
 908 #endif
 909   SafePointNode* _map;
 910   uint           _sp;
 911 
 912  public:
 913   PreserveJVMState(GraphKit* kit, bool clone_map = true);
 914   ~PreserveJVMState();
 915 };
 916 
 917 // Helper class to build cutouts of the form if (p) ; else {x...}.
 918 // The code {x...} must not fall through.
 919 // The kit's main flow of control is set to the "then" continuation of if(p).
 920 class BuildCutout: public PreserveJVMState {
 921  public:
 922   BuildCutout(GraphKit* kit, Node* p, float prob, float cnt = COUNT_UNKNOWN);
 923   ~BuildCutout();
 924 };
 925 
 926 // Helper class to preserve the original _reexecute bit and _sp and restore
 927 // them back
 928 class PreserveReexecuteState: public StackObj {
 929  protected:
 930   GraphKit*                 _kit;
 931   uint                      _sp;
 932   JVMState::ReexecuteState  _reexecute;
 933 
 934  public:
 935   PreserveReexecuteState(GraphKit* kit);
 936   ~PreserveReexecuteState();
 937 };
 938 
 939 #endif // SHARE_VM_OPTO_GRAPHKIT_HPP