1 /*
   2  * Copyright (c) 2005, 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.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "opto/addnode.hpp"
  27 #include "opto/callnode.hpp"
  28 #include "opto/cfgnode.hpp"
  29 #include "opto/idealKit.hpp"
  30 #include "opto/runtime.hpp"
  31 
  32 // Static initialization
  33 
  34 // This declares the position where vars are kept in the cvstate
  35 // For some degree of consistency we use the TypeFunc enum to
  36 // soak up spots in the inputs even though we only use early Control
  37 // and Memory slots. (So far.)
  38 const uint IdealKit::first_var = TypeFunc::Parms + 1;
  39 
  40 //----------------------------IdealKit-----------------------------------------
  41 IdealKit::IdealKit(PhaseGVN &gvn, Node* control, Node* mem, bool delay_all_transforms, bool has_declarations) :
  42   _gvn(gvn), C(gvn.C) {
  43   _initial_ctrl = control;
  44   _initial_memory = mem;
  45   _delay_all_transforms = delay_all_transforms;
  46   _var_ct = 0;
  47   _cvstate = NULL;
  48   // We can go memory state free or else we need the entire memory state
  49   assert(mem == NULL || mem->Opcode() == Op_MergeMem, "memory must be pre-split");
  50   int init_size = 5;
  51   _pending_cvstates = new (C->node_arena()) GrowableArray<Node*>(C->node_arena(), init_size, 0, 0);
  52   _delay_transform  = new (C->node_arena()) GrowableArray<Node*>(C->node_arena(), init_size, 0, 0);
  53   DEBUG_ONLY(_state = new (C->node_arena()) GrowableArray<int>(C->node_arena(), init_size, 0, 0));
  54   if (!has_declarations) {
  55      declarations_done();
  56   }
  57 }
  58 
  59 //-------------------------------if_then-------------------------------------
  60 // Create:  if(left relop right)
  61 //          /  \
  62 //   iffalse    iftrue
  63 // Push the iffalse cvstate onto the stack. The iftrue becomes the current cvstate.
  64 void IdealKit::if_then(Node* left, BoolTest::mask relop,
  65                        Node* right, float prob, float cnt, bool push_new_state) {
  66   assert((state() & (BlockS|LoopS|IfThenS|ElseS)), "bad state for new If");
  67   Node* bol;
  68   if (left->bottom_type()->isa_ptr() == NULL) {
  69     if (left->bottom_type()->isa_int() != NULL) {
  70       bol = Bool(CmpI(left, right), relop);
  71     } else {
  72       assert(left->bottom_type()->isa_long() != NULL, "what else?");
  73       bol = Bool(CmpL(left, right), relop);
  74     }
  75 
  76   } else {
  77     bol = Bool(CmpP(left, right), relop);
  78   }
  79   // Delay gvn.tranform on if-nodes until construction is finished
  80   // to prevent a constant bool input from discarding a control output.
  81   IfNode* iff = delay_transform(new (C, 2) IfNode(ctrl(), bol, prob, cnt))->as_If();
  82   Node* then  = IfTrue(iff);
  83   Node* elsen = IfFalse(iff);
  84   Node* else_cvstate = copy_cvstate();
  85   else_cvstate->set_req(TypeFunc::Control, elsen);
  86   _pending_cvstates->push(else_cvstate);
  87   DEBUG_ONLY(if (push_new_state) _state->push(IfThenS));
  88   set_ctrl(then);
  89 }
  90 
  91 //-------------------------------else_-------------------------------------
  92 // Pop the else cvstate off the stack, and push the (current) then cvstate.
  93 // The else cvstate becomes the current cvstate.
  94 void IdealKit::else_() {
  95   assert(state() == IfThenS, "bad state for new Else");
  96   Node* else_cvstate = _pending_cvstates->pop();
  97   DEBUG_ONLY(_state->pop());
  98   // save current (then) cvstate for later use at endif
  99   _pending_cvstates->push(_cvstate);
 100   DEBUG_ONLY(_state->push(ElseS));
 101   _cvstate = else_cvstate;
 102 }
 103 
 104 //-------------------------------end_if-------------------------------------
 105 // Merge the "then" and "else" cvstates.
 106 //
 107 // The if_then() pushed a copy of the current state for later use
 108 // as the initial state for a future "else" clause.  The
 109 // current state then became the initial state for the
 110 // then clause.  If an "else" clause was encountered, it will
 111 // pop the top state and use it for it's initial state.
 112 // It will also push the current state (the state at the end of
 113 // the "then" clause) for latter use at the end_if.
 114 //
 115 // At the endif, the states are:
 116 // 1) else exists a) current state is end of "else" clause
 117 //                b) top stack state is end of "then" clause
 118 //
 119 // 2) no else:    a) current state is end of "then" clause
 120 //                b) top stack state is from the "if_then" which
 121 //                   would have been the initial state of the else.
 122 //
 123 // Merging the states is accomplished by:
 124 //   1) make a label for the merge
 125 //   2) terminate the current state with a goto to the label
 126 //   3) pop the top state from the stack and make it the
 127 //        current state
 128 //   4) bind the label at the current state.  Binding a label
 129 //        terminates the current state with a goto to the
 130 //        label and makes the label's state the current state.
 131 //
 132 void IdealKit::end_if() {
 133   assert(state() & (IfThenS|ElseS), "bad state for new Endif");
 134   Node* lab = make_label(1);
 135 
 136   // Node* join_state = _pending_cvstates->pop();
 137                   /* merging, join */
 138   goto_(lab);
 139   _cvstate = _pending_cvstates->pop();
 140 
 141   bind(lab);
 142   DEBUG_ONLY(_state->pop());
 143 }
 144 
 145 //-------------------------------loop-------------------------------------
 146 // Create the loop head portion (*) of:
 147 //  *     iv = init
 148 //  *  top: (region node)
 149 //  *     if (iv relop limit) {
 150 //           loop body
 151 //           i = i + 1
 152 //           goto top
 153 //  *     } else // exits loop
 154 //
 155 // Pushes the loop top cvstate first, then the else (loop exit) cvstate
 156 // onto the stack.
 157 void IdealKit::loop(GraphKit* gkit, int nargs, IdealVariable& iv, Node* init, BoolTest::mask relop, Node* limit, float prob, float cnt) {
 158   assert((state() & (BlockS|LoopS|IfThenS|ElseS)), "bad state for new loop");
 159 
 160   // Sync IdealKit and graphKit.
 161   gkit->set_all_memory(this->merged_memory());
 162   gkit->set_control(this->ctrl());
 163   // Add loop predicate.
 164   gkit->add_predicate(nargs);
 165   // Update IdealKit memory.
 166   this->set_all_memory(gkit->merged_memory());
 167   this->set_ctrl(gkit->control());
 168 
 169   set(iv, init);
 170   Node* head = make_label(1);
 171   bind(head);
 172   _pending_cvstates->push(head); // push for use at end_loop
 173   _cvstate = copy_cvstate();
 174   if_then(value(iv), relop, limit, prob, cnt, false /* no new state */);
 175   DEBUG_ONLY(_state->push(LoopS));
 176   assert(ctrl()->is_IfTrue(), "true branch stays in loop");
 177   assert(_pending_cvstates->top()->in(TypeFunc::Control)->is_IfFalse(), "false branch exits loop");
 178 }
 179 
 180 //-------------------------------end_loop-------------------------------------
 181 // Creates the goto top label.
 182 // Expects the else (loop exit) cvstate to be on top of the
 183 // stack, and the loop top cvstate to be 2nd.
 184 void IdealKit::end_loop() {
 185   assert((state() == LoopS), "bad state for new end_loop");
 186   Node* exit = _pending_cvstates->pop();
 187   Node* head = _pending_cvstates->pop();
 188   goto_(head);
 189   clear(head);
 190   DEBUG_ONLY(_state->pop());
 191   _cvstate = exit;
 192 }
 193 
 194 //-------------------------------make_label-------------------------------------
 195 // Creates a label.  The number of goto's
 196 // must be specified (which should be 1 less than
 197 // the number of precedessors.)
 198 Node* IdealKit::make_label(int goto_ct) {
 199   assert(_cvstate != NULL, "must declare variables before labels");
 200   Node* lab = new_cvstate();
 201   int sz = 1 + goto_ct + 1 /* fall thru */;
 202   Node* reg = delay_transform(new (C, sz) RegionNode(sz));
 203   lab->init_req(TypeFunc::Control, reg);
 204   return lab;
 205 }
 206 
 207 //-------------------------------bind-------------------------------------
 208 // Bind a label at the current cvstate by simulating
 209 // a goto to the label.
 210 void IdealKit::bind(Node* lab) {
 211   goto_(lab, true /* bind */);
 212   _cvstate = lab;
 213 }
 214 
 215 //-------------------------------goto_-------------------------------------
 216 // Make the current cvstate a predecessor of the label,
 217 // creating phi's to merge values.  If bind is true and
 218 // this is not the last control edge, then ensure that
 219 // all live values have phis created. Used to create phis
 220 // at loop-top regions.
 221 void IdealKit::goto_(Node* lab, bool bind) {
 222   Node* reg = lab->in(TypeFunc::Control);
 223   // find next empty slot in region
 224   uint slot = 1;
 225   while (slot < reg->req() && reg->in(slot) != NULL) slot++;
 226   assert(slot < reg->req(), "too many gotos");
 227   // If this is last predecessor, then don't force phi creation
 228   if (slot == reg->req() - 1) bind = false;
 229   reg->init_req(slot, ctrl());
 230   assert(first_var + _var_ct == _cvstate->req(), "bad _cvstate size");
 231   for (uint i = first_var; i < _cvstate->req(); i++) {
 232 
 233     // l is the value of var reaching the label. Could be a single value
 234     // reaching the label, or a phi that merges multiples values reaching
 235     // the label.  The latter is true if the label's input: in(..) is
 236     // a phi whose control input is the region node for the label.
 237 
 238     Node* l = lab->in(i);
 239     // Get the current value of the var
 240     Node* m = _cvstate->in(i);
 241     // If the var went unused no need for a phi
 242     if (m == NULL) {
 243       continue;
 244     } else if (l == NULL || m == l) {
 245       // Only one unique value "m" is known to reach this label so a phi
 246       // is not yet necessary unless:
 247       //    the label is being bound and all predecessors have not been seen,
 248       //    in which case "bind" will be true.
 249       if (bind) {
 250         m = promote_to_phi(m, reg);
 251       }
 252       // Record the phi/value used for this var in the label's cvstate
 253       lab->set_req(i, m);
 254     } else {
 255       // More than one value for the variable reaches this label so
 256       // a create a phi if one does not already exist.
 257       if (!was_promoted_to_phi(l, reg)) {
 258         l = promote_to_phi(l, reg);
 259         lab->set_req(i, l);
 260       }
 261       // Record in the phi, the var's value from the current state
 262       l->set_req(slot, m);
 263     }
 264   }
 265   do_memory_merge(_cvstate, lab);
 266   stop();
 267 }
 268 
 269 //-----------------------------promote_to_phi-----------------------------------
 270 Node* IdealKit::promote_to_phi(Node* n, Node* reg) {
 271   assert(!was_promoted_to_phi(n, reg), "n already promoted to phi on this region");
 272   // Get a conservative type for the phi
 273   const BasicType bt = n->bottom_type()->basic_type();
 274   const Type* ct = Type::get_const_basic_type(bt);
 275   return delay_transform(PhiNode::make(reg, n, ct));
 276 }
 277 
 278 //-----------------------------declarations_done-------------------------------
 279 void IdealKit::declarations_done() {
 280   _cvstate = new_cvstate();   // initialize current cvstate
 281   set_ctrl(_initial_ctrl);    // initialize control in current cvstate
 282   set_all_memory(_initial_memory);// initialize memory in current cvstate
 283   DEBUG_ONLY(_state->push(BlockS));
 284 }
 285 
 286 //-----------------------------transform-----------------------------------
 287 Node* IdealKit::transform(Node* n) {
 288   if (_delay_all_transforms) {
 289     return delay_transform(n);
 290   } else {
 291     return gvn().transform(n);
 292   }
 293 }
 294 
 295 //-----------------------------delay_transform-----------------------------------
 296 Node* IdealKit::delay_transform(Node* n) {
 297   if (!gvn().is_IterGVN() || !gvn().is_IterGVN()->delay_transform()) {
 298     gvn().set_type(n, n->bottom_type());
 299   }
 300   _delay_transform->push(n);
 301   return n;
 302 }
 303 
 304 //-----------------------------new_cvstate-----------------------------------
 305 Node* IdealKit::new_cvstate() {
 306   uint sz = _var_ct + first_var;
 307   return new (C, sz) Node(sz);
 308 }
 309 
 310 //-----------------------------copy_cvstate-----------------------------------
 311 Node* IdealKit::copy_cvstate() {
 312   Node* ns = new_cvstate();
 313   for (uint i = 0; i < ns->req(); i++) ns->init_req(i, _cvstate->in(i));
 314   // We must clone memory since it will be updated as we do stores.
 315   ns->set_req(TypeFunc::Memory, MergeMemNode::make(C, ns->in(TypeFunc::Memory)));
 316   return ns;
 317 }
 318 
 319 //-----------------------------clear-----------------------------------
 320 void IdealKit::clear(Node* m) {
 321   for (uint i = 0; i < m->req(); i++) m->set_req(i, NULL);
 322 }
 323 
 324 //-----------------------------drain_delay_transform----------------------------
 325 void IdealKit::drain_delay_transform() {
 326   while (_delay_transform->length() > 0) {
 327     Node* n = _delay_transform->pop();
 328     gvn().transform(n);
 329     if (!gvn().is_IterGVN()) {
 330       C->record_for_igvn(n);
 331     }
 332   }
 333 }
 334 
 335 //-----------------------------IdealVariable----------------------------
 336 IdealVariable::IdealVariable(IdealKit &k) {
 337   k.declare(this);
 338 }
 339 
 340 Node* IdealKit::memory(uint alias_idx) {
 341   MergeMemNode* mem = merged_memory();
 342   Node* p = mem->memory_at(alias_idx);
 343   if (!gvn().is_IterGVN() || !gvn().is_IterGVN()->delay_transform()) {
 344     _gvn.set_type(p, Type::MEMORY);  // must be mapped
 345   }
 346   return p;
 347 }
 348 
 349 void IdealKit::set_memory(Node* mem, uint alias_idx) {
 350   merged_memory()->set_memory_at(alias_idx, mem);
 351 }
 352 
 353 //----------------------------- make_load ----------------------------
 354 Node* IdealKit::load(Node* ctl,
 355                      Node* adr,
 356                      const Type* t,
 357                      BasicType bt,
 358                      int adr_idx,
 359                      bool require_atomic_access) {
 360 
 361   assert(adr_idx != Compile::AliasIdxTop, "use other make_load factory" );
 362   const TypePtr* adr_type = NULL; // debug-mode-only argument
 363   debug_only(adr_type = C->get_adr_type(adr_idx));
 364   Node* mem = memory(adr_idx);
 365   Node* ld;
 366   if (require_atomic_access && bt == T_LONG) {
 367     ld = LoadLNode::make_atomic(C, ctl, mem, adr, adr_type, t);
 368   } else {
 369     ld = LoadNode::make(_gvn, ctl, mem, adr, adr_type, t, bt);
 370   }
 371   return transform(ld);
 372 }
 373 
 374 Node* IdealKit::store(Node* ctl, Node* adr, Node *val, BasicType bt,
 375                                 int adr_idx,
 376                                 bool require_atomic_access) {
 377   assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
 378   const TypePtr* adr_type = NULL;
 379   debug_only(adr_type = C->get_adr_type(adr_idx));
 380   Node *mem = memory(adr_idx);
 381   Node* st;
 382   if (require_atomic_access && bt == T_LONG) {
 383     st = StoreLNode::make_atomic(C, ctl, mem, adr, adr_type, val);
 384   } else {
 385     st = StoreNode::make(_gvn, ctl, mem, adr, adr_type, val, bt);
 386   }
 387   st = transform(st);
 388   set_memory(st, adr_idx);
 389 
 390   return st;
 391 }
 392 
 393 // Card mark store. Must be ordered so that it will come after the store of
 394 // the oop.
 395 Node* IdealKit::storeCM(Node* ctl, Node* adr, Node *val, Node* oop_store, int oop_adr_idx,
 396                         BasicType bt,
 397                         int adr_idx) {
 398   assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
 399   const TypePtr* adr_type = NULL;
 400   debug_only(adr_type = C->get_adr_type(adr_idx));
 401   Node *mem = memory(adr_idx);
 402 
 403   // Add required edge to oop_store, optimizer does not support precedence edges.
 404   // Convert required edge to precedence edge before allocation.
 405   Node* st = new (C, 5) StoreCMNode(ctl, mem, adr, adr_type, val, oop_store, oop_adr_idx);
 406 
 407   st = transform(st);
 408   set_memory(st, adr_idx);
 409 
 410   return st;
 411 }
 412 
 413 //---------------------------- do_memory_merge --------------------------------
 414 // The memory from one merging cvstate needs to be merged with the memory for another
 415 // join cvstate. If the join cvstate doesn't have a merged memory yet then we
 416 // can just copy the state from the merging cvstate
 417 
 418 // Merge one slow path into the rest of memory.
 419 void IdealKit::do_memory_merge(Node* merging, Node* join) {
 420 
 421   // Get the region for the join state
 422   Node* join_region = join->in(TypeFunc::Control);
 423   assert(join_region != NULL, "join region must exist");
 424   if (join->in(TypeFunc::Memory) == NULL ) {
 425     join->set_req(TypeFunc::Memory,  merging->in(TypeFunc::Memory));
 426     return;
 427   }
 428 
 429   // The control flow for merging must have already been attached to the join region
 430   // we need its index for the phis.
 431   uint slot;
 432   for (slot = 1; slot < join_region->req() ; slot ++ ) {
 433     if (join_region->in(slot) == merging->in(TypeFunc::Control)) break;
 434   }
 435   assert(slot !=  join_region->req(), "edge must already exist");
 436 
 437   MergeMemNode* join_m    = join->in(TypeFunc::Memory)->as_MergeMem();
 438   MergeMemNode* merging_m = merging->in(TypeFunc::Memory)->as_MergeMem();
 439 
 440   // join_m should be an ancestor mergemem of merging
 441   // Slow path memory comes from the current map (which is from a slow call)
 442   // Fast path/null path memory comes from the call's input
 443 
 444   // Merge the other fast-memory inputs with the new slow-default memory.
 445   // for (MergeMemStream mms(merged_memory(), fast_mem->as_MergeMem()); mms.next_non_empty2(); ) {
 446   for (MergeMemStream mms(join_m, merging_m); mms.next_non_empty2(); ) {
 447     Node* join_slice = mms.force_memory();
 448     Node* merging_slice = mms.memory2();
 449     if (join_slice != merging_slice) {
 450       PhiNode* phi;
 451       // bool new_phi = false;
 452       // Is the phi for this slice one that we created for this join region or simply
 453       // one we copied? If it is ours then add
 454       if (join_slice->is_Phi() && join_slice->as_Phi()->region() == join_region) {
 455         phi = join_slice->as_Phi();
 456       } else {
 457         // create the phi with join_slice filling supplying memory for all of the
 458         // control edges to the join region
 459         phi = PhiNode::make(join_region, join_slice, Type::MEMORY, mms.adr_type(C));
 460         phi = (PhiNode*) delay_transform(phi);
 461         // gvn().set_type(phi, Type::MEMORY);
 462         // new_phi = true;
 463       }
 464       // Now update the phi with the slice for the merging slice
 465       phi->set_req(slot, merging_slice/* slow_path, slow_slice */);
 466       // this updates join_m with the phi
 467       mms.set_memory(phi);
 468     }
 469   }
 470 }
 471 
 472 
 473 //----------------------------- make_call  ----------------------------
 474 // Trivial runtime call
 475 void IdealKit::make_leaf_call(const TypeFunc *slow_call_type,
 476                               address slow_call,
 477                               const char *leaf_name,
 478                               Node* parm0,
 479                               Node* parm1,
 480                               Node* parm2) {
 481 
 482   // We only handle taking in RawMem and modifying RawMem
 483   const TypePtr* adr_type = TypeRawPtr::BOTTOM;
 484   uint adr_idx = C->get_alias_index(adr_type);
 485 
 486   // Slow-path leaf call
 487   int size = slow_call_type->domain()->cnt();
 488   CallNode *call =  (CallNode*)new (C, size) CallLeafNode( slow_call_type, slow_call, leaf_name, adr_type);
 489 
 490   // Set fixed predefined input arguments
 491   call->init_req( TypeFunc::Control, ctrl() );
 492   call->init_req( TypeFunc::I_O    , top() )     ;   // does no i/o
 493   // Narrow memory as only memory input
 494   call->init_req( TypeFunc::Memory , memory(adr_idx));
 495   call->init_req( TypeFunc::FramePtr, top() /* frameptr() */ );
 496   call->init_req( TypeFunc::ReturnAdr, top() );
 497 
 498   if (parm0 != NULL)  call->init_req(TypeFunc::Parms+0, parm0);
 499   if (parm1 != NULL)  call->init_req(TypeFunc::Parms+1, parm1);
 500   if (parm2 != NULL)  call->init_req(TypeFunc::Parms+2, parm2);
 501 
 502   // Node *c = _gvn.transform(call);
 503   call = (CallNode *) _gvn.transform(call);
 504   Node *c = call; // dbx gets confused with call call->dump()
 505 
 506   // Slow leaf call has no side-effects, sets few values
 507 
 508   set_ctrl(transform( new (C, 1) ProjNode(call,TypeFunc::Control) ));
 509 
 510   // Make memory for the call
 511   Node* mem = _gvn.transform( new (C, 1) ProjNode(call, TypeFunc::Memory) );
 512 
 513   // Set the RawPtr memory state only.
 514   set_memory(mem, adr_idx);
 515 
 516   assert(C->alias_type(call->adr_type()) == C->alias_type(adr_type),
 517          "call node must be constructed correctly");
 518 }