1 /*
   2  * Copyright (c) 2001, 2010, 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.
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  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 Parse;
  45 class RootNode;
  46 
  47 //-----------------------------------------------------------------------------
  48 //----------------------------GraphKit-----------------------------------------
  49 // Toolkit for building the common sorts of subgraphs.
  50 // Does not know about bytecode parsing or type-flow results.
  51 // It is able to create graphs implementing the semantics of most
  52 // or all bytecodes, so that it can expand intrinsics and calls.
  53 // It may depend on JVMState structure, but it must not depend
  54 // on specific bytecode streams.
  55 class GraphKit : public Phase {
  56   friend class PreserveJVMState;
  57 
  58  protected:
  59   ciEnv*            _env;       // Compilation environment
  60   PhaseGVN         &_gvn;       // Some optimizations while parsing
  61   SafePointNode*    _map;       // Parser map from JVM to Nodes
  62   SafePointNode*    _exceptions;// Parser map(s) for exception state(s)
  63   int               _sp;        // JVM Expression Stack Pointer
  64   int               _bci;       // JVM Bytecode Pointer
  65   ciMethod*         _method;    // JVM Current Method
  66 
  67  private:
  68   SafePointNode*     map_not_null() const {
  69     assert(_map != NULL, "must call stopped() to test for reset compiler map");
  70     return _map;
  71   }
  72 
  73  public:
  74   GraphKit();                   // empty constructor
  75   GraphKit(JVMState* jvms);     // the JVM state on which to operate
  76 
  77 #ifdef ASSERT
  78   ~GraphKit() {
  79     assert(!has_exceptions(), "user must call transfer_exceptions_into_jvms");
  80   }
  81 #endif
  82 
  83   virtual Parse* is_Parse() const { return NULL; }
  84 
  85   ciEnv*        env()           const { return _env; }
  86   PhaseGVN&     gvn()           const { return _gvn; }
  87 
  88   void record_for_igvn(Node* n) const { C->record_for_igvn(n); }  // delegate to Compile
  89 
  90   // Handy well-known nodes:
  91   Node*         null()          const { return zerocon(T_OBJECT); }
  92   Node*         top()           const { return C->top(); }
  93   RootNode*     root()          const { return C->root(); }
  94 
  95   // Create or find a constant node
  96   Node* intcon(jint con)        const { return _gvn.intcon(con); }
  97   Node* longcon(jlong con)      const { return _gvn.longcon(con); }
  98   Node* makecon(const Type *t)  const { return _gvn.makecon(t); }
  99   Node* zerocon(BasicType bt)   const { return _gvn.zerocon(bt); }
 100   // (See also macro MakeConX in type.hpp, which uses intcon or longcon.)
 101 
 102   // Helper for byte_map_base
 103   Node* byte_map_base_node() {
 104     // Get base of card map
 105     CardTableModRefBS* ct = (CardTableModRefBS*)(Universe::heap()->barrier_set());
 106     assert(sizeof(*ct->byte_map_base) == sizeof(jbyte), "adjust users of this code");
 107     if (ct->byte_map_base != NULL) {
 108       return makecon(TypeRawPtr::make((address)ct->byte_map_base));
 109     } else {
 110       return null();
 111     }
 112   }
 113 
 114   jint  find_int_con(Node* n, jint value_if_unknown) {
 115     return _gvn.find_int_con(n, value_if_unknown);
 116   }
 117   jlong find_long_con(Node* n, jlong value_if_unknown) {
 118     return _gvn.find_long_con(n, value_if_unknown);
 119   }
 120   // (See also macro find_intptr_t_con in type.hpp, which uses one of these.)
 121 
 122   // JVM State accessors:
 123   // Parser mapping from JVM indices into Nodes.
 124   // Low slots are accessed by the StartNode::enum.
 125   // Then come the locals at StartNode::Parms to StartNode::Parms+max_locals();
 126   // Then come JVM stack slots.
 127   // Finally come the monitors, if any.
 128   // See layout accessors in class JVMState.
 129 
 130   SafePointNode*     map()      const { return _map; }
 131   bool               has_exceptions() const { return _exceptions != NULL; }
 132   JVMState*          jvms()     const { return map_not_null()->_jvms; }
 133   int                sp()       const { return _sp; }
 134   int                bci()      const { return _bci; }
 135   Bytecodes::Code    java_bc()  const;
 136   ciMethod*          method()   const { return _method; }
 137 
 138   void set_jvms(JVMState* jvms)       { set_map(jvms->map());
 139                                         assert(jvms == this->jvms(), "sanity");
 140                                         _sp = jvms->sp();
 141                                         _bci = jvms->bci();
 142                                         _method = jvms->has_method() ? jvms->method() : NULL; }
 143   void set_map(SafePointNode* m)      { _map = m; debug_only(verify_map()); }
 144   void set_sp(int i)                  { assert(i >= 0, "must be non-negative"); _sp = i; }
 145   void clean_stack(int from_sp); // clear garbage beyond from_sp to top
 146 
 147   void inc_sp(int i)                  { set_sp(sp() + i); }
 148   void set_bci(int bci)               { _bci = bci; }
 149 
 150   // Make sure jvms has current bci & sp.
 151   JVMState* sync_jvms()     const;
 152 #ifdef ASSERT
 153   // Make sure JVMS has an updated copy of bci and sp.
 154   // Also sanity-check method, depth, and monitor depth.
 155   bool jvms_in_sync() const;
 156 
 157   // Make sure the map looks OK.
 158   void verify_map() const;
 159 
 160   // Make sure a proposed exception state looks OK.
 161   static void verify_exception_state(SafePointNode* ex_map);
 162 #endif
 163 
 164   // Clone the existing map state.  (Implements PreserveJVMState.)
 165   SafePointNode* clone_map();
 166 
 167   // Set the map to a clone of the given one.
 168   void set_map_clone(SafePointNode* m);
 169 
 170   // Tell if the compilation is failing.
 171   bool failing() const { return C->failing(); }
 172 
 173   // Set _map to NULL, signalling a stop to further bytecode execution.
 174   // Preserve the map intact for future use, and return it back to the caller.
 175   SafePointNode* stop() { SafePointNode* m = map(); set_map(NULL); return m; }
 176 
 177   // Stop, but first smash the map's inputs to NULL, to mark it dead.
 178   void stop_and_kill_map();
 179 
 180   // Tell if _map is NULL, or control is top.
 181   bool stopped();
 182 
 183   // Tell if this method or any caller method has exception handlers.
 184   bool has_ex_handler();
 185 
 186   // Save an exception without blowing stack contents or other JVM state.
 187   // (The extra pointer is stuck with add_req on the map, beyond the JVMS.)
 188   static void set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop);
 189 
 190   // Recover a saved exception from its map.
 191   static Node* saved_ex_oop(SafePointNode* ex_map);
 192 
 193   // Recover a saved exception from its map, and remove it from the map.
 194   static Node* clear_saved_ex_oop(SafePointNode* ex_map);
 195 
 196 #ifdef ASSERT
 197   // Recover a saved exception from its map, and remove it from the map.
 198   static bool has_saved_ex_oop(SafePointNode* ex_map);
 199 #endif
 200 
 201   // Push an exception in the canonical position for handlers (stack(0)).
 202   void push_ex_oop(Node* ex_oop) {
 203     ensure_stack(1);  // ensure room to push the exception
 204     set_stack(0, ex_oop);
 205     set_sp(1);
 206     clean_stack(1);
 207   }
 208 
 209   // Detach and return an exception state.
 210   SafePointNode* pop_exception_state() {
 211     SafePointNode* ex_map = _exceptions;
 212     if (ex_map != NULL) {
 213       _exceptions = ex_map->next_exception();
 214       ex_map->set_next_exception(NULL);
 215       debug_only(verify_exception_state(ex_map));
 216     }
 217     return ex_map;
 218   }
 219 
 220   // Add an exception, using the given JVM state, without commoning.
 221   void push_exception_state(SafePointNode* ex_map) {
 222     debug_only(verify_exception_state(ex_map));
 223     ex_map->set_next_exception(_exceptions);
 224     _exceptions = ex_map;
 225   }
 226 
 227   // Turn the current JVM state into an exception state, appending the ex_oop.
 228   SafePointNode* make_exception_state(Node* ex_oop);
 229 
 230   // Add an exception, using the given JVM state.
 231   // Combine all exceptions with a common exception type into a single state.
 232   // (This is done via combine_exception_states.)
 233   void add_exception_state(SafePointNode* ex_map);
 234 
 235   // Combine all exceptions of any sort whatever into a single master state.
 236   SafePointNode* combine_and_pop_all_exception_states() {
 237     if (_exceptions == NULL)  return NULL;
 238     SafePointNode* phi_map = pop_exception_state();
 239     SafePointNode* ex_map;
 240     while ((ex_map = pop_exception_state()) != NULL) {
 241       combine_exception_states(ex_map, phi_map);
 242     }
 243     return phi_map;
 244   }
 245 
 246   // Combine the two exception states, building phis as necessary.
 247   // The second argument is updated to include contributions from the first.
 248   void combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map);
 249 
 250   // Reset the map to the given state.  If there are any half-finished phis
 251   // in it (created by combine_exception_states), transform them now.
 252   // Returns the exception oop.  (Caller must call push_ex_oop if required.)
 253   Node* use_exception_state(SafePointNode* ex_map);
 254 
 255   // Collect exceptions from a given JVM state into my exception list.
 256   void add_exception_states_from(JVMState* jvms);
 257 
 258   // Collect all raised exceptions into the current JVM state.
 259   // Clear the current exception list and map, returns the combined states.
 260   JVMState* transfer_exceptions_into_jvms();
 261 
 262   // Helper to throw a built-in exception.
 263   // Range checks take the offending index.
 264   // Cast and array store checks take the offending class.
 265   // Others do not take the optional argument.
 266   // The JVMS must allow the bytecode to be re-executed
 267   // via an uncommon trap.
 268   void builtin_throw(Deoptimization::DeoptReason reason, Node* arg = NULL);
 269 
 270   // Helper to check the JavaThread::_should_post_on_exceptions flag
 271   // and branch to an uncommon_trap if it is true (with the specified reason and must_throw)
 272   void uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
 273                                                   bool must_throw) ;
 274 
 275   // Helper Functions for adding debug information
 276   void kill_dead_locals();
 277 #ifdef ASSERT
 278   bool dead_locals_are_killed();
 279 #endif
 280   // The call may deoptimize.  Supply required JVM state as debug info.
 281   // If must_throw is true, the call is guaranteed not to return normally.
 282   void add_safepoint_edges(SafePointNode* call,
 283                            bool must_throw = false);
 284 
 285   // How many stack inputs does the current BC consume?
 286   // And, how does the stack change after the bytecode?
 287   // Returns false if unknown.
 288   bool compute_stack_effects(int& inputs, int& depth);
 289 
 290   // Add a fixed offset to a pointer
 291   Node* basic_plus_adr(Node* base, Node* ptr, intptr_t offset) {
 292     return basic_plus_adr(base, ptr, MakeConX(offset));
 293   }
 294   Node* basic_plus_adr(Node* base, intptr_t offset) {
 295     return basic_plus_adr(base, base, MakeConX(offset));
 296   }
 297   // Add a variable offset to a pointer
 298   Node* basic_plus_adr(Node* base, Node* offset) {
 299     return basic_plus_adr(base, base, offset);
 300   }
 301   Node* basic_plus_adr(Node* base, Node* ptr, Node* offset);
 302 
 303 
 304   // Some convenient shortcuts for common nodes
 305   Node* IfTrue(IfNode* iff)                   { return _gvn.transform(new (C,1) IfTrueNode(iff));      }
 306   Node* IfFalse(IfNode* iff)                  { return _gvn.transform(new (C,1) IfFalseNode(iff));     }
 307 
 308   Node* AddI(Node* l, Node* r)                { return _gvn.transform(new (C,3) AddINode(l, r));       }
 309   Node* SubI(Node* l, Node* r)                { return _gvn.transform(new (C,3) SubINode(l, r));       }
 310   Node* MulI(Node* l, Node* r)                { return _gvn.transform(new (C,3) MulINode(l, r));       }
 311   Node* DivI(Node* ctl, Node* l, Node* r)     { return _gvn.transform(new (C,3) DivINode(ctl, l, r));  }
 312 
 313   Node* AndI(Node* l, Node* r)                { return _gvn.transform(new (C,3) AndINode(l, r));       }
 314   Node* OrI(Node* l, Node* r)                 { return _gvn.transform(new (C,3) OrINode(l, r));        }
 315   Node* XorI(Node* l, Node* r)                { return _gvn.transform(new (C,3) XorINode(l, r));       }
 316 
 317   Node* MaxI(Node* l, Node* r)                { return _gvn.transform(new (C,3) MaxINode(l, r));       }
 318   Node* MinI(Node* l, Node* r)                { return _gvn.transform(new (C,3) MinINode(l, r));       }
 319 
 320   Node* LShiftI(Node* l, Node* r)             { return _gvn.transform(new (C,3) LShiftINode(l, r));    }
 321   Node* RShiftI(Node* l, Node* r)             { return _gvn.transform(new (C,3) RShiftINode(l, r));    }
 322   Node* URShiftI(Node* l, Node* r)            { return _gvn.transform(new (C,3) URShiftINode(l, r));   }
 323 
 324   Node* CmpI(Node* l, Node* r)                { return _gvn.transform(new (C,3) CmpINode(l, r));       }
 325   Node* CmpL(Node* l, Node* r)                { return _gvn.transform(new (C,3) CmpLNode(l, r));       }
 326   Node* CmpP(Node* l, Node* r)                { return _gvn.transform(new (C,3) CmpPNode(l, r));       }
 327   Node* Bool(Node* cmp, BoolTest::mask relop) { return _gvn.transform(new (C,2) BoolNode(cmp, relop)); }
 328 
 329   Node* AddP(Node* b, Node* a, Node* o)       { return _gvn.transform(new (C,4) AddPNode(b, a, o));    }
 330 
 331   // Convert between int and long, and size_t.
 332   // (See macros ConvI2X, etc., in type.hpp for ConvI2X, etc.)
 333   Node* ConvI2L(Node* offset);
 334   Node* ConvL2I(Node* offset);
 335   // Find out the klass of an object.
 336   Node* load_object_klass(Node* object);
 337   // Find out the length of an array.
 338   Node* load_array_length(Node* array);
 339   // Helper function to do a NULL pointer check or ZERO check based on type.
 340   Node* null_check_common(Node* value, BasicType type,
 341                           bool assert_null, Node* *null_control);
 342   // Throw an exception if a given value is null.
 343   // Return the value cast to not-null.
 344   // Be clever about equivalent dominating null checks.
 345   Node* do_null_check(Node* value, BasicType type) {
 346     return null_check_common(value, type, false, NULL);
 347   }
 348   // Throw an uncommon trap if a given value is __not__ null.
 349   // Return the value cast to null, and be clever about dominating checks.
 350   Node* do_null_assert(Node* value, BasicType type) {
 351     return null_check_common(value, type, true, NULL);
 352   }
 353   // Null check oop.  Return null-path control into (*null_control).
 354   // Return a cast-not-null node which depends on the not-null control.
 355   // If never_see_null, use an uncommon trap (*null_control sees a top).
 356   // The cast is not valid along the null path; keep a copy of the original.
 357   Node* null_check_oop(Node* value, Node* *null_control,
 358                        bool never_see_null = false);
 359 
 360   // Check the null_seen bit.
 361   bool seems_never_null(Node* obj, ciProfileData* data);
 362 
 363   // Use the type profile to narrow an object type.
 364   Node* maybe_cast_profiled_receiver(Node* not_null_obj,
 365                                      ciProfileData* data,
 366                                      ciKlass* require_klass);
 367 
 368   // Cast obj to not-null on this path
 369   Node* cast_not_null(Node* obj, bool do_replace_in_map = true);
 370   // Replace all occurrences of one node by another.
 371   void replace_in_map(Node* old, Node* neww);
 372 
 373   void push(Node* n)    { map_not_null(); _map->set_stack(_map->_jvms,_sp++,n); }
 374   Node* pop()           { map_not_null(); return _map->stack(_map->_jvms,--_sp); }
 375   Node* peek(int off=0) { map_not_null(); return _map->stack(_map->_jvms, _sp - off - 1); }
 376 
 377   void push_pair(Node* ldval) {
 378     push(ldval);
 379     push(top());  // the halfword is merely a placeholder
 380   }
 381   void push_pair_local(int i) {
 382     // longs are stored in locals in "push" order
 383     push(  local(i+0) );  // the real value
 384     assert(local(i+1) == top(), "");
 385     push(top());  // halfword placeholder
 386   }
 387   Node* pop_pair() {
 388     // the second half is pushed last & popped first; it contains exactly nothing
 389     Node* halfword = pop();
 390     assert(halfword == top(), "");
 391     // the long bits are pushed first & popped last:
 392     return pop();
 393   }
 394   void set_pair_local(int i, Node* lval) {
 395     // longs are stored in locals as a value/half pair (like doubles)
 396     set_local(i+0, lval);
 397     set_local(i+1, top());
 398   }
 399 
 400   // Push the node, which may be zero, one, or two words.
 401   void push_node(BasicType n_type, Node* n) {
 402     int n_size = type2size[n_type];
 403     if      (n_size == 1)  push(      n );  // T_INT, ...
 404     else if (n_size == 2)  push_pair( n );  // T_DOUBLE, T_LONG
 405     else                   { assert(n_size == 0, "must be T_VOID"); }
 406   }
 407 
 408   Node* pop_node(BasicType n_type) {
 409     int n_size = type2size[n_type];
 410     if      (n_size == 1)  return pop();
 411     else if (n_size == 2)  return pop_pair();
 412     else                   return NULL;
 413   }
 414 
 415   Node* control()               const { return map_not_null()->control(); }
 416   Node* i_o()                   const { return map_not_null()->i_o(); }
 417   Node* returnadr()             const { return map_not_null()->returnadr(); }
 418   Node* frameptr()              const { return map_not_null()->frameptr(); }
 419   Node* local(uint idx)         const { map_not_null(); return _map->local(      _map->_jvms, idx); }
 420   Node* stack(uint idx)         const { map_not_null(); return _map->stack(      _map->_jvms, idx); }
 421   Node* argument(uint idx)      const { map_not_null(); return _map->argument(   _map->_jvms, idx); }
 422   Node* monitor_box(uint idx)   const { map_not_null(); return _map->monitor_box(_map->_jvms, idx); }
 423   Node* monitor_obj(uint idx)   const { map_not_null(); return _map->monitor_obj(_map->_jvms, idx); }
 424 
 425   void set_control  (Node* c)         { map_not_null()->set_control(c); }
 426   void set_i_o      (Node* c)         { map_not_null()->set_i_o(c); }
 427   void set_local(uint idx, Node* c)   { map_not_null(); _map->set_local(   _map->_jvms, idx, c); }
 428   void set_stack(uint idx, Node* c)   { map_not_null(); _map->set_stack(   _map->_jvms, idx, c); }
 429   void set_argument(uint idx, Node* c){ map_not_null(); _map->set_argument(_map->_jvms, idx, c); }
 430   void ensure_stack(uint stk_size)    { map_not_null(); _map->ensure_stack(_map->_jvms, stk_size); }
 431 
 432   // Access unaliased memory
 433   Node* memory(uint alias_idx);
 434   Node* memory(const TypePtr *tp) { return memory(C->get_alias_index(tp)); }
 435   Node* memory(Node* adr) { return memory(_gvn.type(adr)->is_ptr()); }
 436 
 437   // Access immutable memory
 438   Node* immutable_memory() { return C->immutable_memory(); }
 439 
 440   // Set unaliased memory
 441   void set_memory(Node* c, uint alias_idx) { merged_memory()->set_memory_at(alias_idx, c); }
 442   void set_memory(Node* c, const TypePtr *tp) { set_memory(c,C->get_alias_index(tp)); }
 443   void set_memory(Node* c, Node* adr) { set_memory(c,_gvn.type(adr)->is_ptr()); }
 444 
 445   // Get the entire memory state (probably a MergeMemNode), and reset it
 446   // (The resetting prevents somebody from using the dangling Node pointer.)
 447   Node* reset_memory();
 448 
 449   // Get the entire memory state, asserted to be a MergeMemNode.
 450   MergeMemNode* merged_memory() {
 451     Node* mem = map_not_null()->memory();
 452     assert(mem->is_MergeMem(), "parse memory is always pre-split");
 453     return mem->as_MergeMem();
 454   }
 455 
 456   // Set the entire memory state; produce a new MergeMemNode.
 457   void set_all_memory(Node* newmem);
 458 
 459   // Create a memory projection from the call, then set_all_memory.
 460   void set_all_memory_call(Node* call, bool separate_io_proj = false);
 461 
 462   // Create a LoadNode, reading from the parser's memory state.
 463   // (Note:  require_atomic_access is useful only with T_LONG.)
 464   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,
 465                   bool require_atomic_access = false) {
 466     // This version computes alias_index from bottom_type
 467     return make_load(ctl, adr, t, bt, adr->bottom_type()->is_ptr(),
 468                      require_atomic_access);
 469   }
 470   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt, const TypePtr* adr_type, bool require_atomic_access = false) {
 471     // This version computes alias_index from an address type
 472     assert(adr_type != NULL, "use other make_load factory");
 473     return make_load(ctl, adr, t, bt, C->get_alias_index(adr_type),
 474                      require_atomic_access);
 475   }
 476   // This is the base version which is given an alias index.
 477   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt, int adr_idx, bool require_atomic_access = false);
 478 
 479   // Create & transform a StoreNode and store the effect into the
 480   // parser's memory state.
 481   Node* store_to_memory(Node* ctl, Node* adr, Node* val, BasicType bt,
 482                         const TypePtr* adr_type,
 483                         bool require_atomic_access = false) {
 484     // This version computes alias_index from an address type
 485     assert(adr_type != NULL, "use other store_to_memory factory");
 486     return store_to_memory(ctl, adr, val, bt,
 487                            C->get_alias_index(adr_type),
 488                            require_atomic_access);
 489   }
 490   // This is the base version which is given alias index
 491   // Return the new StoreXNode
 492   Node* store_to_memory(Node* ctl, Node* adr, Node* val, BasicType bt,
 493                         int adr_idx,
 494                         bool require_atomic_access = false);
 495 
 496 
 497   // All in one pre-barrier, store, post_barrier
 498   // Insert a write-barrier'd store.  This is to let generational GC
 499   // work; we have to flag all oop-stores before the next GC point.
 500   //
 501   // It comes in 3 flavors of store to an object, array, or unknown.
 502   // We use precise card marks for arrays to avoid scanning the entire
 503   // array. We use imprecise for object. We use precise for unknown
 504   // since we don't know if we have an array or and object or even
 505   // where the object starts.
 506   //
 507   // If val==NULL, it is taken to be a completely unknown value. QQQ
 508 
 509   Node* store_oop(Node* ctl,
 510                   Node* obj,   // containing obj
 511                   Node* adr,  // actual adress to store val at
 512                   const TypePtr* adr_type,
 513                   Node* val,
 514                   const TypeOopPtr* val_type,
 515                   BasicType bt,
 516                   bool use_precise);
 517 
 518   Node* store_oop_to_object(Node* ctl,
 519                             Node* obj,   // containing obj
 520                             Node* adr,  // actual adress to store val at
 521                             const TypePtr* adr_type,
 522                             Node* val,
 523                             const TypeOopPtr* val_type,
 524                             BasicType bt) {
 525     return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, false);
 526   }
 527 
 528   Node* store_oop_to_array(Node* ctl,
 529                            Node* obj,   // containing obj
 530                            Node* adr,  // actual adress to store val at
 531                            const TypePtr* adr_type,
 532                            Node* val,
 533                            const TypeOopPtr* val_type,
 534                            BasicType bt) {
 535     return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, true);
 536   }
 537 
 538   // Could be an array or object we don't know at compile time (unsafe ref.)
 539   Node* store_oop_to_unknown(Node* ctl,
 540                              Node* obj,   // containing obj
 541                              Node* adr,  // actual adress to store val at
 542                              const TypePtr* adr_type,
 543                              Node* val,
 544                              BasicType bt);
 545 
 546   // For the few case where the barriers need special help
 547   void pre_barrier(Node* ctl, Node* obj, Node* adr, uint adr_idx,
 548                    Node* val, const TypeOopPtr* val_type, BasicType bt);
 549 
 550   void post_barrier(Node* ctl, Node* store, Node* obj, Node* adr, uint adr_idx,
 551                     Node* val, BasicType bt, bool use_precise);
 552 
 553   // Return addressing for an array element.
 554   Node* array_element_address(Node* ary, Node* idx, BasicType elembt,
 555                               // Optional constraint on the array size:
 556                               const TypeInt* sizetype = NULL);
 557 
 558   // Return a load of array element at idx.
 559   Node* load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype);
 560 
 561   //---------------- Dtrace support --------------------
 562   void make_dtrace_method_entry_exit(ciMethod* method, bool is_entry);
 563   void make_dtrace_method_entry(ciMethod* method) {
 564     make_dtrace_method_entry_exit(method, true);
 565   }
 566   void make_dtrace_method_exit(ciMethod* method) {
 567     make_dtrace_method_entry_exit(method, false);
 568   }
 569 
 570   //--------------- stub generation -------------------
 571  public:
 572   void gen_stub(address C_function,
 573                 const char *name,
 574                 int is_fancy_jump,
 575                 bool pass_tls,
 576                 bool return_pc);
 577 
 578   //---------- help for generating calls --------------
 579 
 580   // Do a null check on the receiver, which is in argument(0).
 581   Node* null_check_receiver(ciMethod* callee) {
 582     assert(!callee->is_static(), "must be a virtual method");
 583     int nargs = 1 + callee->signature()->size();
 584     // Null check on self without removing any arguments.  The argument
 585     // null check technically happens in the wrong place, which can lead to
 586     // invalid stack traces when the primitive is inlined into a method
 587     // which handles NullPointerExceptions.
 588     Node* receiver = argument(0);
 589     _sp += nargs;
 590     receiver = do_null_check(receiver, T_OBJECT);
 591     _sp -= nargs;
 592     return receiver;
 593   }
 594 
 595   // Fill in argument edges for the call from argument(0), argument(1), ...
 596   // (The next step is to call set_edges_for_java_call.)
 597   void  set_arguments_for_java_call(CallJavaNode* call);
 598 
 599   // Fill in non-argument edges for the call.
 600   // Transform the call, and update the basics: control, i_o, memory.
 601   // (The next step is usually to call set_results_for_java_call.)
 602   void set_edges_for_java_call(CallJavaNode* call,
 603                                bool must_throw = false, bool separate_io_proj = false);
 604 
 605   // Finish up a java call that was started by set_edges_for_java_call.
 606   // Call add_exception on any throw arising from the call.
 607   // Return the call result (transformed).
 608   Node* set_results_for_java_call(CallJavaNode* call, bool separate_io_proj = false);
 609 
 610   // Similar to set_edges_for_java_call, but simplified for runtime calls.
 611   void  set_predefined_output_for_runtime_call(Node* call) {
 612     set_predefined_output_for_runtime_call(call, NULL, NULL);
 613   }
 614   void  set_predefined_output_for_runtime_call(Node* call,
 615                                                Node* keep_mem,
 616                                                const TypePtr* hook_mem);
 617   Node* set_predefined_input_for_runtime_call(SafePointNode* call);
 618 
 619   // Replace the call with the current state of the kit.  Requires
 620   // that the call was generated with separate io_projs so that
 621   // exceptional control flow can be handled properly.
 622   void replace_call(CallNode* call, Node* result);
 623 
 624   // helper functions for statistics
 625   void increment_counter(address counter_addr);   // increment a debug counter
 626   void increment_counter(Node*   counter_addr);   // increment a debug counter
 627 
 628   // Bail out to the interpreter right now
 629   // The optional klass is the one causing the trap.
 630   // The optional reason is debug information written to the compile log.
 631   // Optional must_throw is the same as with add_safepoint_edges.
 632   void uncommon_trap(int trap_request,
 633                      ciKlass* klass = NULL, const char* reason_string = NULL,
 634                      bool must_throw = false, bool keep_exact_action = false);
 635 
 636   // Shorthand, to avoid saying "Deoptimization::" so many times.
 637   void uncommon_trap(Deoptimization::DeoptReason reason,
 638                      Deoptimization::DeoptAction action,
 639                      ciKlass* klass = NULL, const char* reason_string = NULL,
 640                      bool must_throw = false, bool keep_exact_action = false) {
 641     uncommon_trap(Deoptimization::make_trap_request(reason, action),
 642                   klass, reason_string, must_throw, keep_exact_action);
 643   }
 644 
 645   // Report if there were too many traps at the current method and bci.
 646   // Report if a trap was recorded, and/or PerMethodTrapLimit was exceeded.
 647   // If there is no MDO at all, report no trap unless told to assume it.
 648   bool too_many_traps(Deoptimization::DeoptReason reason) {
 649     return C->too_many_traps(method(), bci(), reason);
 650   }
 651 
 652   // Report if there were too many recompiles at the current method and bci.
 653   bool too_many_recompiles(Deoptimization::DeoptReason reason) {
 654     return C->too_many_recompiles(method(), bci(), reason);
 655   }
 656 
 657   // Returns the object (if any) which was created the moment before.
 658   Node* just_allocated_object(Node* current_control);
 659 
 660   static bool use_ReduceInitialCardMarks() {
 661     return (ReduceInitialCardMarks
 662             && Universe::heap()->can_elide_tlab_store_barriers());
 663   }
 664 
 665   void sync_kit(IdealKit& ideal, bool final = true);
 666 
 667   // vanilla/CMS post barrier
 668   void write_barrier_post(Node *store, Node* obj,
 669                           Node* adr,  uint adr_idx, Node* val, bool use_precise);
 670 
 671   // G1 pre/post barriers
 672   void g1_write_barrier_pre(Node* obj,
 673                             Node* adr,
 674                             uint alias_idx,
 675                             Node* val,
 676                             const TypeOopPtr* val_type,
 677                             BasicType bt);
 678 
 679   void g1_write_barrier_post(Node* store,
 680                              Node* obj,
 681                              Node* adr,
 682                              uint alias_idx,
 683                              Node* val,
 684                              BasicType bt,
 685                              bool use_precise);
 686   // Helper function for g1
 687   private:
 688   void g1_mark_card(IdealKit& ideal, Node* card_adr, Node* store, uint oop_alias_idx,
 689                     Node* index, Node* index_adr,
 690                     Node* buffer, const TypeFunc* tf);
 691 
 692   public:
 693   // Helper function to round double arguments before a call
 694   void round_double_arguments(ciMethod* dest_method);
 695   void round_double_result(ciMethod* dest_method);
 696 
 697   // rounding for strict float precision conformance
 698   Node* precision_rounding(Node* n);
 699 
 700   // rounding for strict double precision conformance
 701   Node* dprecision_rounding(Node* n);
 702 
 703   // rounding for non-strict double stores
 704   Node* dstore_rounding(Node* n);
 705 
 706   // Helper functions for fast/slow path codes
 707   Node* opt_iff(Node* region, Node* iff);
 708   Node* make_runtime_call(int flags,
 709                           const TypeFunc* call_type, address call_addr,
 710                           const char* call_name,
 711                           const TypePtr* adr_type, // NULL if no memory effects
 712                           Node* parm0 = NULL, Node* parm1 = NULL,
 713                           Node* parm2 = NULL, Node* parm3 = NULL,
 714                           Node* parm4 = NULL, Node* parm5 = NULL,
 715                           Node* parm6 = NULL, Node* parm7 = NULL);
 716   enum {  // flag values for make_runtime_call
 717     RC_NO_FP = 1,               // CallLeafNoFPNode
 718     RC_NO_IO = 2,               // do not hook IO edges
 719     RC_NO_LEAF = 4,             // CallStaticJavaNode
 720     RC_MUST_THROW = 8,          // flag passed to add_safepoint_edges
 721     RC_NARROW_MEM = 16,         // input memory is same as output
 722     RC_UNCOMMON = 32,           // freq. expected to be like uncommon trap
 723     RC_LEAF = 0                 // null value:  no flags set
 724   };
 725 
 726   // merge in all memory slices from new_mem, along the given path
 727   void merge_memory(Node* new_mem, Node* region, int new_path);
 728   void make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj);
 729 
 730   // Helper functions to build synchronizations
 731   int next_monitor();
 732   Node* insert_mem_bar(int opcode, Node* precedent = NULL);
 733   Node* insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent = NULL);
 734   // Optional 'precedent' is appended as an extra edge, to force ordering.
 735   FastLockNode* shared_lock(Node* obj);
 736   void shared_unlock(Node* box, Node* obj);
 737 
 738   // helper functions for the fast path/slow path idioms
 739   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, klassOop ex_klass, Node* slow_result);
 740 
 741   // Generate an instance-of idiom.  Used by both the instance-of bytecode
 742   // and the reflective instance-of call.
 743   Node* gen_instanceof( Node *subobj, Node* superkls );
 744 
 745   // Generate a check-cast idiom.  Used by both the check-cast bytecode
 746   // and the array-store bytecode
 747   Node* gen_checkcast( Node *subobj, Node* superkls,
 748                        Node* *failure_control = NULL );
 749 
 750   // Generate a subtyping check.  Takes as input the subtype and supertype.
 751   // Returns 2 values: sets the default control() to the true path and
 752   // returns the false path.  Only reads from constant memory taken from the
 753   // default memory; does not write anything.  It also doesn't take in an
 754   // Object; if you wish to check an Object you need to load the Object's
 755   // class prior to coming here.
 756   Node* gen_subtype_check(Node* subklass, Node* superklass);
 757 
 758   // Static parse-time type checking logic for gen_subtype_check:
 759   enum { SSC_always_false, SSC_always_true, SSC_easy_test, SSC_full_test };
 760   int static_subtype_check(ciKlass* superk, ciKlass* subk);
 761 
 762   // Exact type check used for predicted calls and casts.
 763   // Rewrites (*casted_receiver) to be casted to the stronger type.
 764   // (Caller is responsible for doing replace_in_map.)
 765   Node* type_check_receiver(Node* receiver, ciKlass* klass, float prob,
 766                             Node* *casted_receiver);
 767 
 768   // implementation of object creation
 769   Node* set_output_for_allocation(AllocateNode* alloc,
 770                                   const TypeOopPtr* oop_type,
 771                                   bool raw_mem_only);
 772   Node* get_layout_helper(Node* klass_node, jint& constant_value);
 773   Node* new_instance(Node* klass_node,
 774                      Node* slow_test = NULL,
 775                      bool raw_mem_only = false,
 776                      Node* *return_size_val = NULL);
 777   Node* new_array(Node* klass_node, Node* count_val, int nargs,
 778                   bool raw_mem_only = false, Node* *return_size_val = NULL);
 779 
 780   // Handy for making control flow
 781   IfNode* create_and_map_if(Node* ctrl, Node* tst, float prob, float cnt) {
 782     IfNode* iff = new (C, 2) IfNode(ctrl, tst, prob, cnt);// New IfNode's
 783     _gvn.set_type(iff, iff->Value(&_gvn)); // Value may be known at parse-time
 784     // Place 'if' on worklist if it will be in graph
 785     if (!tst->is_Con())  record_for_igvn(iff);     // Range-check and Null-check removal is later
 786     return iff;
 787   }
 788 
 789   IfNode* create_and_xform_if(Node* ctrl, Node* tst, float prob, float cnt) {
 790     IfNode* iff = new (C, 2) IfNode(ctrl, tst, prob, cnt);// New IfNode's
 791     _gvn.transform(iff);                           // Value may be known at parse-time
 792     // Place 'if' on worklist if it will be in graph
 793     if (!tst->is_Con())  record_for_igvn(iff);     // Range-check and Null-check removal is later
 794     return iff;
 795   }
 796 
 797   // Insert a loop predicate into the graph
 798   void add_predicate(int nargs = 0);
 799   void add_predicate_impl(Deoptimization::DeoptReason reason, int nargs);
 800 };
 801 
 802 // Helper class to support building of control flow branches. Upon
 803 // creation the map and sp at bci are cloned and restored upon de-
 804 // struction. Typical use:
 805 //
 806 // { PreserveJVMState pjvms(this);
 807 //   // code of new branch
 808 // }
 809 // // here the JVM state at bci is established
 810 
 811 class PreserveJVMState: public StackObj {
 812  protected:
 813   GraphKit*      _kit;
 814 #ifdef ASSERT
 815   int            _block;  // PO of current block, if a Parse
 816   int            _bci;
 817 #endif
 818   SafePointNode* _map;
 819   uint           _sp;
 820 
 821  public:
 822   PreserveJVMState(GraphKit* kit, bool clone_map = true);
 823   ~PreserveJVMState();
 824 };
 825 
 826 // Helper class to build cutouts of the form if (p) ; else {x...}.
 827 // The code {x...} must not fall through.
 828 // The kit's main flow of control is set to the "then" continuation of if(p).
 829 class BuildCutout: public PreserveJVMState {
 830  public:
 831   BuildCutout(GraphKit* kit, Node* p, float prob, float cnt = COUNT_UNKNOWN);
 832   ~BuildCutout();
 833 };
 834 
 835 // Helper class to preserve the original _reexecute bit and _sp and restore
 836 // them back
 837 class PreserveReexecuteState: public StackObj {
 838  protected:
 839   GraphKit*                 _kit;
 840   uint                      _sp;
 841   JVMState::ReexecuteState  _reexecute;
 842 
 843  public:
 844   PreserveReexecuteState(GraphKit* kit);
 845   ~PreserveReexecuteState();
 846 };
 847 
 848 #endif // SHARE_VM_OPTO_GRAPHKIT_HPP