1 /*
   2  * Copyright (c) 2001, 2012, 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 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 dec_sp(int i)                  { set_sp(sp() - i); }
 149   void set_bci(int bci)               { _bci = bci; }
 150 
 151   // Make sure jvms has current bci & sp.
 152   JVMState* sync_jvms()     const;
 153 #ifdef ASSERT
 154   // Make sure JVMS has an updated copy of bci and sp.
 155   // Also sanity-check method, depth, and monitor depth.
 156   bool jvms_in_sync() const;
 157 
 158   // Make sure the map looks OK.
 159   void verify_map() const;
 160 
 161   // Make sure a proposed exception state looks OK.
 162   static void verify_exception_state(SafePointNode* ex_map);
 163 #endif
 164 
 165   // Clone the existing map state.  (Implements PreserveJVMState.)
 166   SafePointNode* clone_map();
 167 
 168   // Set the map to a clone of the given one.
 169   void set_map_clone(SafePointNode* m);
 170 
 171   // Tell if the compilation is failing.
 172   bool failing() const { return C->failing(); }
 173 
 174   // Set _map to NULL, signalling a stop to further bytecode execution.
 175   // Preserve the map intact for future use, and return it back to the caller.
 176   SafePointNode* stop() { SafePointNode* m = map(); set_map(NULL); return m; }
 177 
 178   // Stop, but first smash the map's inputs to NULL, to mark it dead.
 179   void stop_and_kill_map();
 180 
 181   // Tell if _map is NULL, or control is top.
 182   bool stopped();
 183 
 184   // Tell if this method or any caller method has exception handlers.
 185   bool has_ex_handler();
 186 
 187   // Save an exception without blowing stack contents or other JVM state.
 188   // (The extra pointer is stuck with add_req on the map, beyond the JVMS.)
 189   static void set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop);
 190 
 191   // Recover a saved exception from its map.
 192   static Node* saved_ex_oop(SafePointNode* ex_map);
 193 
 194   // Recover a saved exception from its map, and remove it from the map.
 195   static Node* clear_saved_ex_oop(SafePointNode* ex_map);
 196 
 197 #ifdef ASSERT
 198   // Recover a saved exception from its map, and remove it from the map.
 199   static bool has_saved_ex_oop(SafePointNode* ex_map);
 200 #endif
 201 
 202   // Push an exception in the canonical position for handlers (stack(0)).
 203   void push_ex_oop(Node* ex_oop) {
 204     ensure_stack(1);  // ensure room to push the exception
 205     set_stack(0, ex_oop);
 206     set_sp(1);
 207     clean_stack(1);
 208   }
 209 
 210   // Detach and return an exception state.
 211   SafePointNode* pop_exception_state() {
 212     SafePointNode* ex_map = _exceptions;
 213     if (ex_map != NULL) {
 214       _exceptions = ex_map->next_exception();
 215       ex_map->set_next_exception(NULL);
 216       debug_only(verify_exception_state(ex_map));
 217     }
 218     return ex_map;
 219   }
 220 
 221   // Add an exception, using the given JVM state, without commoning.
 222   void push_exception_state(SafePointNode* ex_map) {
 223     debug_only(verify_exception_state(ex_map));
 224     ex_map->set_next_exception(_exceptions);
 225     _exceptions = ex_map;
 226   }
 227 
 228   // Turn the current JVM state into an exception state, appending the ex_oop.
 229   SafePointNode* make_exception_state(Node* ex_oop);
 230 
 231   // Add an exception, using the given JVM state.
 232   // Combine all exceptions with a common exception type into a single state.
 233   // (This is done via combine_exception_states.)
 234   void add_exception_state(SafePointNode* ex_map);
 235 
 236   // Combine all exceptions of any sort whatever into a single master state.
 237   SafePointNode* combine_and_pop_all_exception_states() {
 238     if (_exceptions == NULL)  return NULL;
 239     SafePointNode* phi_map = pop_exception_state();
 240     SafePointNode* ex_map;
 241     while ((ex_map = pop_exception_state()) != NULL) {
 242       combine_exception_states(ex_map, phi_map);
 243     }
 244     return phi_map;
 245   }
 246 
 247   // Combine the two exception states, building phis as necessary.
 248   // The second argument is updated to include contributions from the first.
 249   void combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map);
 250 
 251   // Reset the map to the given state.  If there are any half-finished phis
 252   // in it (created by combine_exception_states), transform them now.
 253   // Returns the exception oop.  (Caller must call push_ex_oop if required.)
 254   Node* use_exception_state(SafePointNode* ex_map);
 255 
 256   // Collect exceptions from a given JVM state into my exception list.
 257   void add_exception_states_from(JVMState* jvms);
 258 
 259   // Collect all raised exceptions into the current JVM state.
 260   // Clear the current exception list and map, returns the combined states.
 261   JVMState* transfer_exceptions_into_jvms();
 262 
 263   // Helper to throw a built-in exception.
 264   // Range checks take the offending index.
 265   // Cast and array store checks take the offending class.
 266   // Others do not take the optional argument.
 267   // The JVMS must allow the bytecode to be re-executed
 268   // via an uncommon trap.
 269   void builtin_throw(Deoptimization::DeoptReason reason, Node* arg = NULL);
 270 
 271   // Helper to check the JavaThread::_should_post_on_exceptions flag
 272   // and branch to an uncommon_trap if it is true (with the specified reason and must_throw)
 273   void uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
 274                                                   bool must_throw) ;
 275 
 276   // Helper Functions for adding debug information
 277   void kill_dead_locals();
 278 #ifdef ASSERT
 279   bool dead_locals_are_killed();
 280 #endif
 281   // The call may deoptimize.  Supply required JVM state as debug info.
 282   // If must_throw is true, the call is guaranteed not to return normally.
 283   void add_safepoint_edges(SafePointNode* call,
 284                            bool must_throw = false);
 285 
 286   // How many stack inputs does the current BC consume?
 287   // And, how does the stack change after the bytecode?
 288   // Returns false if unknown.
 289   bool compute_stack_effects(int& inputs, int& depth, bool for_parse = false);
 290 
 291   // Add a fixed offset to a pointer
 292   Node* basic_plus_adr(Node* base, Node* ptr, intptr_t offset) {
 293     return basic_plus_adr(base, ptr, MakeConX(offset));
 294   }
 295   Node* basic_plus_adr(Node* base, intptr_t offset) {
 296     return basic_plus_adr(base, base, MakeConX(offset));
 297   }
 298   // Add a variable offset to a pointer
 299   Node* basic_plus_adr(Node* base, Node* offset) {
 300     return basic_plus_adr(base, base, offset);
 301   }
 302   Node* basic_plus_adr(Node* base, Node* ptr, Node* offset);
 303 
 304 
 305   // Some convenient shortcuts for common nodes
 306   Node* IfTrue(IfNode* iff)                   { return _gvn.transform(new (C,1) IfTrueNode(iff));      }
 307   Node* IfFalse(IfNode* iff)                  { return _gvn.transform(new (C,1) IfFalseNode(iff));     }
 308 
 309   Node* AddI(Node* l, Node* r)                { return _gvn.transform(new (C,3) AddINode(l, r));       }
 310   Node* SubI(Node* l, Node* r)                { return _gvn.transform(new (C,3) SubINode(l, r));       }
 311   Node* MulI(Node* l, Node* r)                { return _gvn.transform(new (C,3) MulINode(l, r));       }
 312   Node* DivI(Node* ctl, Node* l, Node* r)     { return _gvn.transform(new (C,3) DivINode(ctl, l, r));  }
 313 
 314   Node* AndI(Node* l, Node* r)                { return _gvn.transform(new (C,3) AndINode(l, r));       }
 315   Node* OrI(Node* l, Node* r)                 { return _gvn.transform(new (C,3) OrINode(l, r));        }
 316   Node* XorI(Node* l, Node* r)                { return _gvn.transform(new (C,3) XorINode(l, r));       }
 317 
 318   Node* MaxI(Node* l, Node* r)                { return _gvn.transform(new (C,3) MaxINode(l, r));       }
 319   Node* MinI(Node* l, Node* r)                { return _gvn.transform(new (C,3) MinINode(l, r));       }
 320 
 321   Node* LShiftI(Node* l, Node* r)             { return _gvn.transform(new (C,3) LShiftINode(l, r));    }
 322   Node* RShiftI(Node* l, Node* r)             { return _gvn.transform(new (C,3) RShiftINode(l, r));    }
 323   Node* URShiftI(Node* l, Node* r)            { return _gvn.transform(new (C,3) URShiftINode(l, r));   }
 324 
 325   Node* CmpI(Node* l, Node* r)                { return _gvn.transform(new (C,3) CmpINode(l, r));       }
 326   Node* CmpL(Node* l, Node* r)                { return _gvn.transform(new (C,3) CmpLNode(l, r));       }
 327   Node* CmpP(Node* l, Node* r)                { return _gvn.transform(new (C,3) CmpPNode(l, r));       }
 328   Node* Bool(Node* cmp, BoolTest::mask relop) { return _gvn.transform(new (C,2) BoolNode(cmp, relop)); }
 329 
 330   Node* AddP(Node* b, Node* a, Node* o)       { return _gvn.transform(new (C,4) AddPNode(b, a, o));    }
 331 
 332   // Convert between int and long, and size_t.
 333   // (See macros ConvI2X, etc., in type.hpp for ConvI2X, etc.)
 334   Node* ConvI2L(Node* offset);
 335   Node* ConvL2I(Node* offset);
 336   // Find out the klass of an object.
 337   Node* load_object_klass(Node* object);
 338   // Find out the length of an array.
 339   Node* load_array_length(Node* array);
 340   // Helper function to do a NULL pointer check or ZERO check based on type.
 341   Node* null_check_common(Node* value, BasicType type,
 342                           bool assert_null, Node* *null_control);
 343   // Throw an exception if a given value is null.
 344   // Return the value cast to not-null.
 345   // Be clever about equivalent dominating null checks.
 346   Node* do_null_check(Node* value, BasicType type) {
 347     return null_check_common(value, type, false, NULL);
 348   }
 349   // Throw an uncommon trap if a given value is __not__ null.
 350   // Return the value cast to null, and be clever about dominating checks.
 351   Node* do_null_assert(Node* value, BasicType type) {
 352     return null_check_common(value, type, true, NULL);
 353   }
 354   // Null check oop.  Return null-path control into (*null_control).
 355   // Return a cast-not-null node which depends on the not-null control.
 356   // If never_see_null, use an uncommon trap (*null_control sees a top).
 357   // The cast is not valid along the null path; keep a copy of the original.
 358   Node* null_check_oop(Node* value, Node* *null_control,
 359                        bool never_see_null = false);
 360 
 361   // Check the null_seen bit.
 362   bool seems_never_null(Node* obj, ciProfileData* data);
 363 
 364   // Use the type profile to narrow an object type.
 365   Node* maybe_cast_profiled_receiver(Node* not_null_obj,
 366                                      ciProfileData* data,
 367                                      ciKlass* require_klass);
 368 
 369   // Cast obj to not-null on this path
 370   Node* cast_not_null(Node* obj, bool do_replace_in_map = true);
 371   // Replace all occurrences of one node by another.
 372   void replace_in_map(Node* old, Node* neww);
 373 
 374   void  push(Node* n)     { map_not_null();        _map->set_stack(_map->_jvms,   _sp++, n); }
 375   Node* pop()             { map_not_null(); return _map->stack(    _map->_jvms, --_sp); }
 376   Node* peek(int off = 0) { map_not_null(); return _map->stack(    _map->_jvms,   _sp - off - 1); }
 377 
 378   void push_pair(Node* ldval) {
 379     push(ldval);
 380     push(top());  // the halfword is merely a placeholder
 381   }
 382   void push_pair_local(int i) {
 383     // longs are stored in locals in "push" order
 384     push(  local(i+0) );  // the real value
 385     assert(local(i+1) == top(), "");
 386     push(top());  // halfword placeholder
 387   }
 388   Node* pop_pair() {
 389     // the second half is pushed last & popped first; it contains exactly nothing
 390     Node* halfword = pop();
 391     assert(halfword == top(), "");
 392     // the long bits are pushed first & popped last:
 393     return pop();
 394   }
 395   void set_pair_local(int i, Node* lval) {
 396     // longs are stored in locals as a value/half pair (like doubles)
 397     set_local(i+0, lval);
 398     set_local(i+1, top());
 399   }
 400 
 401   // Push the node, which may be zero, one, or two words.
 402   void push_node(BasicType n_type, Node* n) {
 403     int n_size = type2size[n_type];
 404     if      (n_size == 1)  push(      n );  // T_INT, ...
 405     else if (n_size == 2)  push_pair( n );  // T_DOUBLE, T_LONG
 406     else                   { assert(n_size == 0, "must be T_VOID"); }
 407   }
 408 
 409   Node* pop_node(BasicType n_type) {
 410     int n_size = type2size[n_type];
 411     if      (n_size == 1)  return pop();
 412     else if (n_size == 2)  return pop_pair();
 413     else                   return NULL;
 414   }
 415 
 416   Node* control()               const { return map_not_null()->control(); }
 417   Node* i_o()                   const { return map_not_null()->i_o(); }
 418   Node* returnadr()             const { return map_not_null()->returnadr(); }
 419   Node* frameptr()              const { return map_not_null()->frameptr(); }
 420   Node* local(uint idx)         const { map_not_null(); return _map->local(      _map->_jvms, idx); }
 421   Node* stack(uint idx)         const { map_not_null(); return _map->stack(      _map->_jvms, idx); }
 422   Node* argument(uint idx)      const { map_not_null(); return _map->argument(   _map->_jvms, idx); }
 423   Node* monitor_box(uint idx)   const { map_not_null(); return _map->monitor_box(_map->_jvms, idx); }
 424   Node* monitor_obj(uint idx)   const { map_not_null(); return _map->monitor_obj(_map->_jvms, idx); }
 425 
 426   void set_control  (Node* c)         { map_not_null()->set_control(c); }
 427   void set_i_o      (Node* c)         { map_not_null()->set_i_o(c); }
 428   void set_local(uint idx, Node* c)   { map_not_null(); _map->set_local(   _map->_jvms, idx, c); }
 429   void set_stack(uint idx, Node* c)   { map_not_null(); _map->set_stack(   _map->_jvms, idx, c); }
 430   void set_argument(uint idx, Node* c){ map_not_null(); _map->set_argument(_map->_jvms, idx, c); }
 431   void ensure_stack(uint stk_size)    { map_not_null(); _map->ensure_stack(_map->_jvms, stk_size); }
 432 
 433   // Access unaliased memory
 434   Node* memory(uint alias_idx);
 435   Node* memory(const TypePtr *tp) { return memory(C->get_alias_index(tp)); }
 436   Node* memory(Node* adr) { return memory(_gvn.type(adr)->is_ptr()); }
 437 
 438   // Access immutable memory
 439   Node* immutable_memory() { return C->immutable_memory(); }
 440 
 441   // Set unaliased memory
 442   void set_memory(Node* c, uint alias_idx) { merged_memory()->set_memory_at(alias_idx, c); }
 443   void set_memory(Node* c, const TypePtr *tp) { set_memory(c,C->get_alias_index(tp)); }
 444   void set_memory(Node* c, Node* adr) { set_memory(c,_gvn.type(adr)->is_ptr()); }
 445 
 446   // Get the entire memory state (probably a MergeMemNode), and reset it
 447   // (The resetting prevents somebody from using the dangling Node pointer.)
 448   Node* reset_memory();
 449 
 450   // Get the entire memory state, asserted to be a MergeMemNode.
 451   MergeMemNode* merged_memory() {
 452     Node* mem = map_not_null()->memory();
 453     assert(mem->is_MergeMem(), "parse memory is always pre-split");
 454     return mem->as_MergeMem();
 455   }
 456 
 457   // Set the entire memory state; produce a new MergeMemNode.
 458   void set_all_memory(Node* newmem);
 459 
 460   // Create a memory projection from the call, then set_all_memory.
 461   void set_all_memory_call(Node* call, bool separate_io_proj = false);
 462 
 463   // Create a LoadNode, reading from the parser's memory state.
 464   // (Note:  require_atomic_access is useful only with T_LONG.)
 465   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,
 466                   bool require_atomic_access = false) {
 467     // This version computes alias_index from bottom_type
 468     return make_load(ctl, adr, t, bt, adr->bottom_type()->is_ptr(),
 469                      require_atomic_access);
 470   }
 471   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt, const TypePtr* adr_type, bool require_atomic_access = false) {
 472     // This version computes alias_index from an address type
 473     assert(adr_type != NULL, "use other make_load factory");
 474     return make_load(ctl, adr, t, bt, C->get_alias_index(adr_type),
 475                      require_atomic_access);
 476   }
 477   // This is the base version which is given an alias index.
 478   Node* make_load(Node* ctl, Node* adr, const Type* t, BasicType bt, int adr_idx, bool require_atomic_access = false);
 479 
 480   // Create & transform a StoreNode and store the effect into the
 481   // parser's memory state.
 482   Node* store_to_memory(Node* ctl, Node* adr, Node* val, BasicType bt,
 483                         const TypePtr* adr_type,
 484                         bool require_atomic_access = false) {
 485     // This version computes alias_index from an address type
 486     assert(adr_type != NULL, "use other store_to_memory factory");
 487     return store_to_memory(ctl, adr, val, bt,
 488                            C->get_alias_index(adr_type),
 489                            require_atomic_access);
 490   }
 491   // This is the base version which is given alias index
 492   // Return the new StoreXNode
 493   Node* store_to_memory(Node* ctl, Node* adr, Node* val, BasicType bt,
 494                         int adr_idx,
 495                         bool require_atomic_access = false);
 496 
 497 
 498   // All in one pre-barrier, store, post_barrier
 499   // Insert a write-barrier'd store.  This is to let generational GC
 500   // work; we have to flag all oop-stores before the next GC point.
 501   //
 502   // It comes in 3 flavors of store to an object, array, or unknown.
 503   // We use precise card marks for arrays to avoid scanning the entire
 504   // array. We use imprecise for object. We use precise for unknown
 505   // since we don't know if we have an array or and object or even
 506   // where the object starts.
 507   //
 508   // If val==NULL, it is taken to be a completely unknown value. QQQ
 509 
 510   Node* store_oop(Node* ctl,
 511                   Node* obj,   // containing obj
 512                   Node* adr,  // actual adress to store val at
 513                   const TypePtr* adr_type,
 514                   Node* val,
 515                   const TypeOopPtr* val_type,
 516                   BasicType bt,
 517                   bool use_precise);
 518 
 519   Node* store_oop_to_object(Node* ctl,
 520                             Node* obj,   // containing obj
 521                             Node* adr,  // actual adress to store val at
 522                             const TypePtr* adr_type,
 523                             Node* val,
 524                             const TypeOopPtr* val_type,
 525                             BasicType bt) {
 526     return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, false);
 527   }
 528 
 529   Node* store_oop_to_array(Node* ctl,
 530                            Node* obj,   // containing obj
 531                            Node* adr,  // actual adress to store val at
 532                            const TypePtr* adr_type,
 533                            Node* val,
 534                            const TypeOopPtr* val_type,
 535                            BasicType bt) {
 536     return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, true);
 537   }
 538 
 539   // Could be an array or object we don't know at compile time (unsafe ref.)
 540   Node* store_oop_to_unknown(Node* ctl,
 541                              Node* obj,   // containing obj
 542                              Node* adr,  // actual adress to store val at
 543                              const TypePtr* adr_type,
 544                              Node* val,
 545                              BasicType bt);
 546 
 547   // For the few case where the barriers need special help
 548   void pre_barrier(bool do_load, Node* ctl,
 549                    Node* obj, Node* adr, uint adr_idx, Node* val, const TypeOopPtr* val_type,
 550                    Node* pre_val,
 551                    BasicType bt);
 552 
 553   void post_barrier(Node* ctl, Node* store, Node* obj, Node* adr, uint adr_idx,
 554                     Node* val, BasicType bt, bool use_precise);
 555 
 556   // Return addressing for an array element.
 557   Node* array_element_address(Node* ary, Node* idx, BasicType elembt,
 558                               // Optional constraint on the array size:
 559                               const TypeInt* sizetype = NULL);
 560 
 561   // Return a load of array element at idx.
 562   Node* load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype);
 563 
 564   //---------------- Dtrace support --------------------
 565   void make_dtrace_method_entry_exit(ciMethod* method, bool is_entry);
 566   void make_dtrace_method_entry(ciMethod* method) {
 567     make_dtrace_method_entry_exit(method, true);
 568   }
 569   void make_dtrace_method_exit(ciMethod* method) {
 570     make_dtrace_method_entry_exit(method, false);
 571   }
 572 
 573   //--------------- stub generation -------------------
 574  public:
 575   void gen_stub(address C_function,
 576                 const char *name,
 577                 int is_fancy_jump,
 578                 bool pass_tls,
 579                 bool return_pc);
 580 
 581   //---------- help for generating calls --------------
 582 
 583   // Do a null check on the receiver, which is in argument(0).
 584   Node* null_check_receiver(ciMethod* callee) {
 585     assert(!callee->is_static(), "must be a virtual method");
 586     int nargs = 1 + callee->signature()->size();
 587     // Null check on self without removing any arguments.  The argument
 588     // null check technically happens in the wrong place, which can lead to
 589     // invalid stack traces when the primitive is inlined into a method
 590     // which handles NullPointerExceptions.
 591     Node* receiver = argument(0);
 592     _sp += nargs;
 593     receiver = do_null_check(receiver, T_OBJECT);
 594     _sp -= nargs;
 595     return receiver;
 596   }
 597 
 598   // Fill in argument edges for the call from argument(0), argument(1), ...
 599   // (The next step is to call set_edges_for_java_call.)
 600   void  set_arguments_for_java_call(CallJavaNode* call);
 601 
 602   // Fill in non-argument edges for the call.
 603   // Transform the call, and update the basics: control, i_o, memory.
 604   // (The next step is usually to call set_results_for_java_call.)
 605   void set_edges_for_java_call(CallJavaNode* call,
 606                                bool must_throw = false, bool separate_io_proj = false);
 607 
 608   // Finish up a java call that was started by set_edges_for_java_call.
 609   // Call add_exception on any throw arising from the call.
 610   // Return the call result (transformed).
 611   Node* set_results_for_java_call(CallJavaNode* call, bool separate_io_proj = false);
 612 
 613   // Similar to set_edges_for_java_call, but simplified for runtime calls.
 614   void  set_predefined_output_for_runtime_call(Node* call) {
 615     set_predefined_output_for_runtime_call(call, NULL, NULL);
 616   }
 617   void  set_predefined_output_for_runtime_call(Node* call,
 618                                                Node* keep_mem,
 619                                                const TypePtr* hook_mem);
 620   Node* set_predefined_input_for_runtime_call(SafePointNode* call);
 621 
 622   // Replace the call with the current state of the kit.  Requires
 623   // that the call was generated with separate io_projs so that
 624   // exceptional control flow can be handled properly.
 625   void replace_call(CallNode* call, Node* result);
 626 
 627   // helper functions for statistics
 628   void increment_counter(address counter_addr);   // increment a debug counter
 629   void increment_counter(Node*   counter_addr);   // increment a debug counter
 630 
 631   // Bail out to the interpreter right now
 632   // The optional klass is the one causing the trap.
 633   // The optional reason is debug information written to the compile log.
 634   // Optional must_throw is the same as with add_safepoint_edges.
 635   void uncommon_trap(int trap_request,
 636                      ciKlass* klass = NULL, const char* reason_string = NULL,
 637                      bool must_throw = false, bool keep_exact_action = false);
 638 
 639   // Shorthand, to avoid saying "Deoptimization::" so many times.
 640   void uncommon_trap(Deoptimization::DeoptReason reason,
 641                      Deoptimization::DeoptAction action,
 642                      ciKlass* klass = NULL, const char* reason_string = NULL,
 643                      bool must_throw = false, bool keep_exact_action = false) {
 644     uncommon_trap(Deoptimization::make_trap_request(reason, action),
 645                   klass, reason_string, must_throw, keep_exact_action);
 646   }
 647 
 648   // Report if there were too many traps at the current method and bci.
 649   // Report if a trap was recorded, and/or PerMethodTrapLimit was exceeded.
 650   // If there is no MDO at all, report no trap unless told to assume it.
 651   bool too_many_traps(Deoptimization::DeoptReason reason) {
 652     return C->too_many_traps(method(), bci(), reason);
 653   }
 654 
 655   // Report if there were too many recompiles at the current method and bci.
 656   bool too_many_recompiles(Deoptimization::DeoptReason reason) {
 657     return C->too_many_recompiles(method(), bci(), reason);
 658   }
 659 
 660   // Returns the object (if any) which was created the moment before.
 661   Node* just_allocated_object(Node* current_control);
 662 
 663   static bool use_ReduceInitialCardMarks() {
 664     return (ReduceInitialCardMarks
 665             && Universe::heap()->can_elide_tlab_store_barriers());
 666   }
 667 
 668   // Sync Ideal and Graph kits.
 669   void sync_kit(IdealKit& ideal);
 670   void final_sync(IdealKit& ideal);
 671 
 672   // vanilla/CMS post barrier
 673   void write_barrier_post(Node *store, Node* obj,
 674                           Node* adr,  uint adr_idx, Node* val, bool use_precise);
 675 
 676   // G1 pre/post barriers
 677   void g1_write_barrier_pre(bool do_load,
 678                             Node* obj,
 679                             Node* adr,
 680                             uint alias_idx,
 681                             Node* val,
 682                             const TypeOopPtr* val_type,
 683                             Node* pre_val,
 684                             BasicType bt);
 685 
 686   void g1_write_barrier_post(Node* store,
 687                              Node* obj,
 688                              Node* adr,
 689                              uint alias_idx,
 690                              Node* val,
 691                              BasicType bt,
 692                              bool use_precise);
 693   // Helper function for g1
 694   private:
 695   void g1_mark_card(IdealKit& ideal, Node* card_adr, Node* store, uint oop_alias_idx,
 696                     Node* index, Node* index_adr,
 697                     Node* buffer, const TypeFunc* tf);
 698 
 699   public:
 700   // Helper function to round double arguments before a call
 701   void round_double_arguments(ciMethod* dest_method);
 702   void round_double_result(ciMethod* dest_method);
 703 
 704   // rounding for strict float precision conformance
 705   Node* precision_rounding(Node* n);
 706 
 707   // rounding for strict double precision conformance
 708   Node* dprecision_rounding(Node* n);
 709 
 710   // rounding for non-strict double stores
 711   Node* dstore_rounding(Node* n);
 712 
 713   // Helper functions for fast/slow path codes
 714   Node* opt_iff(Node* region, Node* iff);
 715   Node* make_runtime_call(int flags,
 716                           const TypeFunc* call_type, address call_addr,
 717                           const char* call_name,
 718                           const TypePtr* adr_type, // NULL if no memory effects
 719                           Node* parm0 = NULL, Node* parm1 = NULL,
 720                           Node* parm2 = NULL, Node* parm3 = NULL,
 721                           Node* parm4 = NULL, Node* parm5 = NULL,
 722                           Node* parm6 = NULL, Node* parm7 = NULL);
 723   enum {  // flag values for make_runtime_call
 724     RC_NO_FP = 1,               // CallLeafNoFPNode
 725     RC_NO_IO = 2,               // do not hook IO edges
 726     RC_NO_LEAF = 4,             // CallStaticJavaNode
 727     RC_MUST_THROW = 8,          // flag passed to add_safepoint_edges
 728     RC_NARROW_MEM = 16,         // input memory is same as output
 729     RC_UNCOMMON = 32,           // freq. expected to be like uncommon trap
 730     RC_LEAF = 0                 // null value:  no flags set
 731   };
 732 
 733   // merge in all memory slices from new_mem, along the given path
 734   void merge_memory(Node* new_mem, Node* region, int new_path);
 735   void make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj);
 736 
 737   // Helper functions to build synchronizations
 738   int next_monitor();
 739   Node* insert_mem_bar(int opcode, Node* precedent = NULL);
 740   Node* insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent = NULL);
 741   // Optional 'precedent' is appended as an extra edge, to force ordering.
 742   FastLockNode* shared_lock(Node* obj);
 743   void shared_unlock(Node* box, Node* obj);
 744 
 745   // helper functions for the fast path/slow path idioms
 746   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);
 747 
 748   // Generate an instance-of idiom.  Used by both the instance-of bytecode
 749   // and the reflective instance-of call.
 750   Node* gen_instanceof( Node *subobj, Node* superkls );
 751 
 752   // Generate a check-cast idiom.  Used by both the check-cast bytecode
 753   // and the array-store bytecode
 754   Node* gen_checkcast( Node *subobj, Node* superkls,
 755                        Node* *failure_control = NULL );
 756 
 757   // helper functions that correctly interacts with the GVN depending
 758   // on the current compiler phase
 759   static Node *gvn_transform(Node *n, PhaseGVN* gvn) {
 760     if (gvn->is_IterGVN() == NULL) {
 761       return gvn->transform(n);
 762     } else {
 763       gvn->is_IterGVN()->register_new_node_with_optimizer(n);
 764       return n;
 765     }
 766     return NULL;
 767   }
 768 
 769   static void gvn_transform_ctrl(Node *n, PhaseGVN* gvn) {
 770     if (gvn->is_IterGVN() == NULL) {
 771       gvn->C->record_for_igvn(n);
 772     }
 773   }
 774 
 775   // Generate a subtyping check.  Takes as input the subtype and supertype.
 776   // Returns 2 values: sets the default control() to the true path and
 777   // returns the false path.  Only reads from constant memory taken from the
 778   // default memory; does not write anything.  It also doesn't take in an
 779   // Object; if you wish to check an Object you need to load the Object's
 780   // class prior to coming here.
 781   static Node* gen_subtype_check_any_phase(Node* subklass, Node* superklass, Node** ctrl, MergeMemNode* mem, PhaseGVN* gvn);
 782 
 783   Node* gen_subtype_check(Node* subklass, Node* superklass) {
 784     MergeMemNode* mem = merged_memory();
 785     Node* ctrl = control();
 786     Node* n = gen_subtype_check_any_phase(subklass, superklass, &ctrl, mem, &_gvn);
 787     set_control(ctrl);
 788     return n;
 789   }
 790 
 791   // Exact type check used for predicted calls and casts.
 792   // Rewrites (*casted_receiver) to be casted to the stronger type.
 793   // (Caller is responsible for doing replace_in_map.)
 794   Node* type_check_receiver(Node* receiver, ciKlass* klass, float prob,
 795                             Node* *casted_receiver);
 796 
 797   // implementation of object creation
 798   Node* set_output_for_allocation(AllocateNode* alloc,
 799                                   const TypeOopPtr* oop_type);
 800   Node* get_layout_helper(Node* klass_node, jint& constant_value);
 801   Node* new_instance(Node* klass_node,
 802                      Node* slow_test = NULL,
 803                      Node* *return_size_val = NULL);
 804   Node* new_array(Node* klass_node, Node* count_val, int nargs,
 805                   Node* *return_size_val = NULL);
 806 
 807   // java.lang.String helpers
 808   Node* load_String_offset(Node* ctrl, Node* str);
 809   Node* load_String_length(Node* ctrl, Node* str);
 810   Node* load_String_value(Node* ctrl, Node* str);
 811   void store_String_offset(Node* ctrl, Node* str, Node* value);
 812   void store_String_length(Node* ctrl, Node* str, Node* value);
 813   void store_String_value(Node* ctrl, Node* str, Node* value);
 814 
 815   // Handy for making control flow
 816   IfNode* create_and_map_if(Node* ctrl, Node* tst, float prob, float cnt) {
 817     IfNode* iff = new (C, 2) IfNode(ctrl, tst, prob, cnt);// New IfNode's
 818     _gvn.set_type(iff, iff->Value(&_gvn)); // Value may be known at parse-time
 819     // Place 'if' on worklist if it will be in graph
 820     if (!tst->is_Con())  record_for_igvn(iff);     // Range-check and Null-check removal is later
 821     return iff;
 822   }
 823 
 824   IfNode* create_and_xform_if(Node* ctrl, Node* tst, float prob, float cnt) {
 825     IfNode* iff = new (C, 2) IfNode(ctrl, tst, prob, cnt);// New IfNode's
 826     _gvn.transform(iff);                           // Value may be known at parse-time
 827     // Place 'if' on worklist if it will be in graph
 828     if (!tst->is_Con())  record_for_igvn(iff);     // Range-check and Null-check removal is later
 829     return iff;
 830   }
 831 
 832   // Insert a loop predicate into the graph
 833   void add_predicate(int nargs = 0);
 834   void add_predicate_impl(Deoptimization::DeoptReason reason, int nargs);
 835 };
 836 
 837 // Helper class to support building of control flow branches. Upon
 838 // creation the map and sp at bci are cloned and restored upon de-
 839 // struction. Typical use:
 840 //
 841 // { PreserveJVMState pjvms(this);
 842 //   // code of new branch
 843 // }
 844 // // here the JVM state at bci is established
 845 
 846 class PreserveJVMState: public StackObj {
 847  protected:
 848   GraphKit*      _kit;
 849 #ifdef ASSERT
 850   int            _block;  // PO of current block, if a Parse
 851   int            _bci;
 852 #endif
 853   SafePointNode* _map;
 854   uint           _sp;
 855 
 856  public:
 857   PreserveJVMState(GraphKit* kit, bool clone_map = true);
 858   ~PreserveJVMState();
 859 };
 860 
 861 // Helper class to build cutouts of the form if (p) ; else {x...}.
 862 // The code {x...} must not fall through.
 863 // The kit's main flow of control is set to the "then" continuation of if(p).
 864 class BuildCutout: public PreserveJVMState {
 865  public:
 866   BuildCutout(GraphKit* kit, Node* p, float prob, float cnt = COUNT_UNKNOWN);
 867   ~BuildCutout();
 868 };
 869 
 870 // Helper class to preserve the original _reexecute bit and _sp and restore
 871 // them back
 872 class PreserveReexecuteState: public StackObj {
 873  protected:
 874   GraphKit*                 _kit;
 875   uint                      _sp;
 876   JVMState::ReexecuteState  _reexecute;
 877 
 878  public:
 879   PreserveReexecuteState(GraphKit* kit);
 880   ~PreserveReexecuteState();
 881 };
 882 
 883 #endif // SHARE_VM_OPTO_GRAPHKIT_HPP