src/share/vm/opto/node.cpp

Fri, 27 Feb 2009 13:27:09 -0800

author
twisti
date
Fri, 27 Feb 2009 13:27:09 -0800
changeset 1040
98cb887364d3
parent 740
ab075d07f1ba
child 1844
cff162798819
permissions
-rw-r--r--

6810672: Comment typos
Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never

     1 /*
     2  * Copyright 1997-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
    21  * have any questions.
    22  *
    23  */
    25 #include "incls/_precompiled.incl"
    26 #include "incls/_node.cpp.incl"
    28 class RegMask;
    29 // #include "phase.hpp"
    30 class PhaseTransform;
    31 class PhaseGVN;
    33 // Arena we are currently building Nodes in
    34 const uint Node::NotAMachineReg = 0xffff0000;
    36 #ifndef PRODUCT
    37 extern int nodes_created;
    38 #endif
    40 #ifdef ASSERT
    42 //-------------------------- construct_node------------------------------------
    43 // Set a breakpoint here to identify where a particular node index is built.
    44 void Node::verify_construction() {
    45   _debug_orig = NULL;
    46   int old_debug_idx = Compile::debug_idx();
    47   int new_debug_idx = old_debug_idx+1;
    48   if (new_debug_idx > 0) {
    49     // Arrange that the lowest five decimal digits of _debug_idx
    50     // will repeat thos of _idx.  In case this is somehow pathological,
    51     // we continue to assign negative numbers (!) consecutively.
    52     const int mod = 100000;
    53     int bump = (int)(_idx - new_debug_idx) % mod;
    54     if (bump < 0)  bump += mod;
    55     assert(bump >= 0 && bump < mod, "");
    56     new_debug_idx += bump;
    57   }
    58   Compile::set_debug_idx(new_debug_idx);
    59   set_debug_idx( new_debug_idx );
    60   assert(Compile::current()->unique() < (uint)MaxNodeLimit, "Node limit exceeded");
    61   if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (int)_idx == BreakAtNode)) {
    62     tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d", _idx, _debug_idx);
    63     BREAKPOINT;
    64   }
    65 #if OPTO_DU_ITERATOR_ASSERT
    66   _last_del = NULL;
    67   _del_tick = 0;
    68 #endif
    69   _hash_lock = 0;
    70 }
    73 // #ifdef ASSERT ...
    75 #if OPTO_DU_ITERATOR_ASSERT
    76 void DUIterator_Common::sample(const Node* node) {
    77   _vdui     = VerifyDUIterators;
    78   _node     = node;
    79   _outcnt   = node->_outcnt;
    80   _del_tick = node->_del_tick;
    81   _last     = NULL;
    82 }
    84 void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
    85   assert(_node     == node, "consistent iterator source");
    86   assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
    87 }
    89 void DUIterator_Common::verify_resync() {
    90   // Ensure that the loop body has just deleted the last guy produced.
    91   const Node* node = _node;
    92   // Ensure that at least one copy of the last-seen edge was deleted.
    93   // Note:  It is OK to delete multiple copies of the last-seen edge.
    94   // Unfortunately, we have no way to verify that all the deletions delete
    95   // that same edge.  On this point we must use the Honor System.
    96   assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
    97   assert(node->_last_del == _last, "must have deleted the edge just produced");
    98   // We liked this deletion, so accept the resulting outcnt and tick.
    99   _outcnt   = node->_outcnt;
   100   _del_tick = node->_del_tick;
   101 }
   103 void DUIterator_Common::reset(const DUIterator_Common& that) {
   104   if (this == &that)  return;  // ignore assignment to self
   105   if (!_vdui) {
   106     // We need to initialize everything, overwriting garbage values.
   107     _last = that._last;
   108     _vdui = that._vdui;
   109   }
   110   // Note:  It is legal (though odd) for an iterator over some node x
   111   // to be reassigned to iterate over another node y.  Some doubly-nested
   112   // progress loops depend on being able to do this.
   113   const Node* node = that._node;
   114   // Re-initialize everything, except _last.
   115   _node     = node;
   116   _outcnt   = node->_outcnt;
   117   _del_tick = node->_del_tick;
   118 }
   120 void DUIterator::sample(const Node* node) {
   121   DUIterator_Common::sample(node);      // Initialize the assertion data.
   122   _refresh_tick = 0;                    // No refreshes have happened, as yet.
   123 }
   125 void DUIterator::verify(const Node* node, bool at_end_ok) {
   126   DUIterator_Common::verify(node, at_end_ok);
   127   assert(_idx      <  node->_outcnt + (uint)at_end_ok, "idx in range");
   128 }
   130 void DUIterator::verify_increment() {
   131   if (_refresh_tick & 1) {
   132     // We have refreshed the index during this loop.
   133     // Fix up _idx to meet asserts.
   134     if (_idx > _outcnt)  _idx = _outcnt;
   135   }
   136   verify(_node, true);
   137 }
   139 void DUIterator::verify_resync() {
   140   // Note:  We do not assert on _outcnt, because insertions are OK here.
   141   DUIterator_Common::verify_resync();
   142   // Make sure we are still in sync, possibly with no more out-edges:
   143   verify(_node, true);
   144 }
   146 void DUIterator::reset(const DUIterator& that) {
   147   if (this == &that)  return;  // self assignment is always a no-op
   148   assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
   149   assert(that._idx          == 0, "assign only the result of Node::outs()");
   150   assert(_idx               == that._idx, "already assigned _idx");
   151   if (!_vdui) {
   152     // We need to initialize everything, overwriting garbage values.
   153     sample(that._node);
   154   } else {
   155     DUIterator_Common::reset(that);
   156     if (_refresh_tick & 1) {
   157       _refresh_tick++;                  // Clear the "was refreshed" flag.
   158     }
   159     assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
   160   }
   161 }
   163 void DUIterator::refresh() {
   164   DUIterator_Common::sample(_node);     // Re-fetch assertion data.
   165   _refresh_tick |= 1;                   // Set the "was refreshed" flag.
   166 }
   168 void DUIterator::verify_finish() {
   169   // If the loop has killed the node, do not require it to re-run.
   170   if (_node->_outcnt == 0)  _refresh_tick &= ~1;
   171   // If this assert triggers, it means that a loop used refresh_out_pos
   172   // to re-synch an iteration index, but the loop did not correctly
   173   // re-run itself, using a "while (progress)" construct.
   174   // This iterator enforces the rule that you must keep trying the loop
   175   // until it "runs clean" without any need for refreshing.
   176   assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
   177 }
   180 void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
   181   DUIterator_Common::verify(node, at_end_ok);
   182   Node** out    = node->_out;
   183   uint   cnt    = node->_outcnt;
   184   assert(cnt == _outcnt, "no insertions allowed");
   185   assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
   186   // This last check is carefully designed to work for NO_OUT_ARRAY.
   187 }
   189 void DUIterator_Fast::verify_limit() {
   190   const Node* node = _node;
   191   verify(node, true);
   192   assert(_outp == node->_out + node->_outcnt, "limit still correct");
   193 }
   195 void DUIterator_Fast::verify_resync() {
   196   const Node* node = _node;
   197   if (_outp == node->_out + _outcnt) {
   198     // Note that the limit imax, not the pointer i, gets updated with the
   199     // exact count of deletions.  (For the pointer it's always "--i".)
   200     assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
   201     // This is a limit pointer, with a name like "imax".
   202     // Fudge the _last field so that the common assert will be happy.
   203     _last = (Node*) node->_last_del;
   204     DUIterator_Common::verify_resync();
   205   } else {
   206     assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
   207     // A normal internal pointer.
   208     DUIterator_Common::verify_resync();
   209     // Make sure we are still in sync, possibly with no more out-edges:
   210     verify(node, true);
   211   }
   212 }
   214 void DUIterator_Fast::verify_relimit(uint n) {
   215   const Node* node = _node;
   216   assert((int)n > 0, "use imax -= n only with a positive count");
   217   // This must be a limit pointer, with a name like "imax".
   218   assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
   219   // The reported number of deletions must match what the node saw.
   220   assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
   221   // Fudge the _last field so that the common assert will be happy.
   222   _last = (Node*) node->_last_del;
   223   DUIterator_Common::verify_resync();
   224 }
   226 void DUIterator_Fast::reset(const DUIterator_Fast& that) {
   227   assert(_outp              == that._outp, "already assigned _outp");
   228   DUIterator_Common::reset(that);
   229 }
   231 void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
   232   // at_end_ok means the _outp is allowed to underflow by 1
   233   _outp += at_end_ok;
   234   DUIterator_Fast::verify(node, at_end_ok);  // check _del_tick, etc.
   235   _outp -= at_end_ok;
   236   assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
   237 }
   239 void DUIterator_Last::verify_limit() {
   240   // Do not require the limit address to be resynched.
   241   //verify(node, true);
   242   assert(_outp == _node->_out, "limit still correct");
   243 }
   245 void DUIterator_Last::verify_step(uint num_edges) {
   246   assert((int)num_edges > 0, "need non-zero edge count for loop progress");
   247   _outcnt   -= num_edges;
   248   _del_tick += num_edges;
   249   // Make sure we are still in sync, possibly with no more out-edges:
   250   const Node* node = _node;
   251   verify(node, true);
   252   assert(node->_last_del == _last, "must have deleted the edge just produced");
   253 }
   255 #endif //OPTO_DU_ITERATOR_ASSERT
   258 #endif //ASSERT
   261 // This constant used to initialize _out may be any non-null value.
   262 // The value NULL is reserved for the top node only.
   263 #define NO_OUT_ARRAY ((Node**)-1)
   265 // This funny expression handshakes with Node::operator new
   266 // to pull Compile::current out of the new node's _out field,
   267 // and then calls a subroutine which manages most field
   268 // initializations.  The only one which is tricky is the
   269 // _idx field, which is const, and so must be initialized
   270 // by a return value, not an assignment.
   271 //
   272 // (Aren't you thankful that Java finals don't require so many tricks?)
   273 #define IDX_INIT(req) this->Init((req), (Compile*) this->_out)
   274 #ifdef _MSC_VER // the IDX_INIT hack falls foul of warning C4355
   275 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
   276 #endif
   278 // Out-of-line code from node constructors.
   279 // Executed only when extra debug info. is being passed around.
   280 static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
   281   C->set_node_notes_at(idx, nn);
   282 }
   284 // Shared initialization code.
   285 inline int Node::Init(int req, Compile* C) {
   286   assert(Compile::current() == C, "must use operator new(Compile*)");
   287   int idx = C->next_unique();
   289   // If there are default notes floating around, capture them:
   290   Node_Notes* nn = C->default_node_notes();
   291   if (nn != NULL)  init_node_notes(C, idx, nn);
   293   // Note:  At this point, C is dead,
   294   // and we begin to initialize the new Node.
   296   _cnt = _max = req;
   297   _outcnt = _outmax = 0;
   298   _class_id = Class_Node;
   299   _flags = 0;
   300   _out = NO_OUT_ARRAY;
   301   return idx;
   302 }
   304 //------------------------------Node-------------------------------------------
   305 // Create a Node, with a given number of required edges.
   306 Node::Node(uint req)
   307   : _idx(IDX_INIT(req))
   308 {
   309   assert( req < (uint)(MaxNodeLimit - NodeLimitFudgeFactor), "Input limit exceeded" );
   310   debug_only( verify_construction() );
   311   NOT_PRODUCT(nodes_created++);
   312   if (req == 0) {
   313     assert( _in == (Node**)this, "Must not pass arg count to 'new'" );
   314     _in = NULL;
   315   } else {
   316     assert( _in[req-1] == this, "Must pass arg count to 'new'" );
   317     Node** to = _in;
   318     for(uint i = 0; i < req; i++) {
   319       to[i] = NULL;
   320     }
   321   }
   322 }
   324 //------------------------------Node-------------------------------------------
   325 Node::Node(Node *n0)
   326   : _idx(IDX_INIT(1))
   327 {
   328   debug_only( verify_construction() );
   329   NOT_PRODUCT(nodes_created++);
   330   // Assert we allocated space for input array already
   331   assert( _in[0] == this, "Must pass arg count to 'new'" );
   332   assert( is_not_dead(n0), "can not use dead node");
   333   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
   334 }
   336 //------------------------------Node-------------------------------------------
   337 Node::Node(Node *n0, Node *n1)
   338   : _idx(IDX_INIT(2))
   339 {
   340   debug_only( verify_construction() );
   341   NOT_PRODUCT(nodes_created++);
   342   // Assert we allocated space for input array already
   343   assert( _in[1] == this, "Must pass arg count to 'new'" );
   344   assert( is_not_dead(n0), "can not use dead node");
   345   assert( is_not_dead(n1), "can not use dead node");
   346   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
   347   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
   348 }
   350 //------------------------------Node-------------------------------------------
   351 Node::Node(Node *n0, Node *n1, Node *n2)
   352   : _idx(IDX_INIT(3))
   353 {
   354   debug_only( verify_construction() );
   355   NOT_PRODUCT(nodes_created++);
   356   // Assert we allocated space for input array already
   357   assert( _in[2] == this, "Must pass arg count to 'new'" );
   358   assert( is_not_dead(n0), "can not use dead node");
   359   assert( is_not_dead(n1), "can not use dead node");
   360   assert( is_not_dead(n2), "can not use dead node");
   361   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
   362   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
   363   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
   364 }
   366 //------------------------------Node-------------------------------------------
   367 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
   368   : _idx(IDX_INIT(4))
   369 {
   370   debug_only( verify_construction() );
   371   NOT_PRODUCT(nodes_created++);
   372   // Assert we allocated space for input array already
   373   assert( _in[3] == this, "Must pass arg count to 'new'" );
   374   assert( is_not_dead(n0), "can not use dead node");
   375   assert( is_not_dead(n1), "can not use dead node");
   376   assert( is_not_dead(n2), "can not use dead node");
   377   assert( is_not_dead(n3), "can not use dead node");
   378   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
   379   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
   380   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
   381   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
   382 }
   384 //------------------------------Node-------------------------------------------
   385 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
   386   : _idx(IDX_INIT(5))
   387 {
   388   debug_only( verify_construction() );
   389   NOT_PRODUCT(nodes_created++);
   390   // Assert we allocated space for input array already
   391   assert( _in[4] == this, "Must pass arg count to 'new'" );
   392   assert( is_not_dead(n0), "can not use dead node");
   393   assert( is_not_dead(n1), "can not use dead node");
   394   assert( is_not_dead(n2), "can not use dead node");
   395   assert( is_not_dead(n3), "can not use dead node");
   396   assert( is_not_dead(n4), "can not use dead node");
   397   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
   398   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
   399   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
   400   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
   401   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
   402 }
   404 //------------------------------Node-------------------------------------------
   405 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
   406                      Node *n4, Node *n5)
   407   : _idx(IDX_INIT(6))
   408 {
   409   debug_only( verify_construction() );
   410   NOT_PRODUCT(nodes_created++);
   411   // Assert we allocated space for input array already
   412   assert( _in[5] == this, "Must pass arg count to 'new'" );
   413   assert( is_not_dead(n0), "can not use dead node");
   414   assert( is_not_dead(n1), "can not use dead node");
   415   assert( is_not_dead(n2), "can not use dead node");
   416   assert( is_not_dead(n3), "can not use dead node");
   417   assert( is_not_dead(n4), "can not use dead node");
   418   assert( is_not_dead(n5), "can not use dead node");
   419   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
   420   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
   421   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
   422   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
   423   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
   424   _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
   425 }
   427 //------------------------------Node-------------------------------------------
   428 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
   429                      Node *n4, Node *n5, Node *n6)
   430   : _idx(IDX_INIT(7))
   431 {
   432   debug_only( verify_construction() );
   433   NOT_PRODUCT(nodes_created++);
   434   // Assert we allocated space for input array already
   435   assert( _in[6] == this, "Must pass arg count to 'new'" );
   436   assert( is_not_dead(n0), "can not use dead node");
   437   assert( is_not_dead(n1), "can not use dead node");
   438   assert( is_not_dead(n2), "can not use dead node");
   439   assert( is_not_dead(n3), "can not use dead node");
   440   assert( is_not_dead(n4), "can not use dead node");
   441   assert( is_not_dead(n5), "can not use dead node");
   442   assert( is_not_dead(n6), "can not use dead node");
   443   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
   444   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
   445   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
   446   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
   447   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
   448   _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
   449   _in[6] = n6; if (n6 != NULL) n6->add_out((Node *)this);
   450 }
   453 //------------------------------clone------------------------------------------
   454 // Clone a Node.
   455 Node *Node::clone() const {
   456   Compile *compile = Compile::current();
   457   uint s = size_of();           // Size of inherited Node
   458   Node *n = (Node*)compile->node_arena()->Amalloc_D(size_of() + _max*sizeof(Node*));
   459   Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
   460   // Set the new input pointer array
   461   n->_in = (Node**)(((char*)n)+s);
   462   // Cannot share the old output pointer array, so kill it
   463   n->_out = NO_OUT_ARRAY;
   464   // And reset the counters to 0
   465   n->_outcnt = 0;
   466   n->_outmax = 0;
   467   // Unlock this guy, since he is not in any hash table.
   468   debug_only(n->_hash_lock = 0);
   469   // Walk the old node's input list to duplicate its edges
   470   uint i;
   471   for( i = 0; i < len(); i++ ) {
   472     Node *x = in(i);
   473     n->_in[i] = x;
   474     if (x != NULL) x->add_out(n);
   475   }
   476   if (is_macro())
   477     compile->add_macro_node(n);
   479   n->set_idx(compile->next_unique()); // Get new unique index as well
   480   debug_only( n->verify_construction() );
   481   NOT_PRODUCT(nodes_created++);
   482   // Do not patch over the debug_idx of a clone, because it makes it
   483   // impossible to break on the clone's moment of creation.
   484   //debug_only( n->set_debug_idx( debug_idx() ) );
   486   compile->copy_node_notes_to(n, (Node*) this);
   488   // MachNode clone
   489   uint nopnds;
   490   if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
   491     MachNode *mach  = n->as_Mach();
   492     MachNode *mthis = this->as_Mach();
   493     // Get address of _opnd_array.
   494     // It should be the same offset since it is the clone of this node.
   495     MachOper **from = mthis->_opnds;
   496     MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
   497                     pointer_delta((const void*)from,
   498                                   (const void*)(&mthis->_opnds), 1));
   499     mach->_opnds = to;
   500     for ( uint i = 0; i < nopnds; ++i ) {
   501       to[i] = from[i]->clone(compile);
   502     }
   503   }
   504   // cloning CallNode may need to clone JVMState
   505   if (n->is_Call()) {
   506     CallNode *call = n->as_Call();
   507     call->clone_jvms();
   508   }
   509   return n;                     // Return the clone
   510 }
   512 //---------------------------setup_is_top--------------------------------------
   513 // Call this when changing the top node, to reassert the invariants
   514 // required by Node::is_top.  See Compile::set_cached_top_node.
   515 void Node::setup_is_top() {
   516   if (this == (Node*)Compile::current()->top()) {
   517     // This node has just become top.  Kill its out array.
   518     _outcnt = _outmax = 0;
   519     _out = NULL;                           // marker value for top
   520     assert(is_top(), "must be top");
   521   } else {
   522     if (_out == NULL)  _out = NO_OUT_ARRAY;
   523     assert(!is_top(), "must not be top");
   524   }
   525 }
   528 //------------------------------~Node------------------------------------------
   529 // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
   530 extern int reclaim_idx ;
   531 extern int reclaim_in  ;
   532 extern int reclaim_node;
   533 void Node::destruct() {
   534   // Eagerly reclaim unique Node numberings
   535   Compile* compile = Compile::current();
   536   if ((uint)_idx+1 == compile->unique()) {
   537     compile->set_unique(compile->unique()-1);
   538 #ifdef ASSERT
   539     reclaim_idx++;
   540 #endif
   541   }
   542   // Clear debug info:
   543   Node_Notes* nn = compile->node_notes_at(_idx);
   544   if (nn != NULL)  nn->clear();
   545   // Walk the input array, freeing the corresponding output edges
   546   _cnt = _max;  // forget req/prec distinction
   547   uint i;
   548   for( i = 0; i < _max; i++ ) {
   549     set_req(i, NULL);
   550     //assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
   551   }
   552   assert(outcnt() == 0, "deleting a node must not leave a dangling use");
   553   // See if the input array was allocated just prior to the object
   554   int edge_size = _max*sizeof(void*);
   555   int out_edge_size = _outmax*sizeof(void*);
   556   char *edge_end = ((char*)_in) + edge_size;
   557   char *out_array = (char*)(_out == NO_OUT_ARRAY? NULL: _out);
   558   char *out_edge_end = out_array + out_edge_size;
   559   int node_size = size_of();
   561   // Free the output edge array
   562   if (out_edge_size > 0) {
   563 #ifdef ASSERT
   564     if( out_edge_end == compile->node_arena()->hwm() )
   565       reclaim_in  += out_edge_size;  // count reclaimed out edges with in edges
   566 #endif
   567     compile->node_arena()->Afree(out_array, out_edge_size);
   568   }
   570   // Free the input edge array and the node itself
   571   if( edge_end == (char*)this ) {
   572 #ifdef ASSERT
   573     if( edge_end+node_size == compile->node_arena()->hwm() ) {
   574       reclaim_in  += edge_size;
   575       reclaim_node+= node_size;
   576     }
   577 #else
   578     // It was; free the input array and object all in one hit
   579     compile->node_arena()->Afree(_in,edge_size+node_size);
   580 #endif
   581   } else {
   583     // Free just the input array
   584 #ifdef ASSERT
   585     if( edge_end == compile->node_arena()->hwm() )
   586       reclaim_in  += edge_size;
   587 #endif
   588     compile->node_arena()->Afree(_in,edge_size);
   590     // Free just the object
   591 #ifdef ASSERT
   592     if( ((char*)this) + node_size == compile->node_arena()->hwm() )
   593       reclaim_node+= node_size;
   594 #else
   595     compile->node_arena()->Afree(this,node_size);
   596 #endif
   597   }
   598   if (is_macro()) {
   599     compile->remove_macro_node(this);
   600   }
   601 #ifdef ASSERT
   602   // We will not actually delete the storage, but we'll make the node unusable.
   603   *(address*)this = badAddress;  // smash the C++ vtbl, probably
   604   _in = _out = (Node**) badAddress;
   605   _max = _cnt = _outmax = _outcnt = 0;
   606 #endif
   607 }
   609 //------------------------------grow-------------------------------------------
   610 // Grow the input array, making space for more edges
   611 void Node::grow( uint len ) {
   612   Arena* arena = Compile::current()->node_arena();
   613   uint new_max = _max;
   614   if( new_max == 0 ) {
   615     _max = 4;
   616     _in = (Node**)arena->Amalloc(4*sizeof(Node*));
   617     Node** to = _in;
   618     to[0] = NULL;
   619     to[1] = NULL;
   620     to[2] = NULL;
   621     to[3] = NULL;
   622     return;
   623   }
   624   while( new_max <= len ) new_max <<= 1; // Find next power-of-2
   625   // Trimming to limit allows a uint8 to handle up to 255 edges.
   626   // Previously I was using only powers-of-2 which peaked at 128 edges.
   627   //if( new_max >= limit ) new_max = limit-1;
   628   _in = (Node**)arena->Arealloc(_in, _max*sizeof(Node*), new_max*sizeof(Node*));
   629   Copy::zero_to_bytes(&_in[_max], (new_max-_max)*sizeof(Node*)); // NULL all new space
   630   _max = new_max;               // Record new max length
   631   // This assertion makes sure that Node::_max is wide enough to
   632   // represent the numerical value of new_max.
   633   assert(_max == new_max && _max > len, "int width of _max is too small");
   634 }
   636 //-----------------------------out_grow----------------------------------------
   637 // Grow the input array, making space for more edges
   638 void Node::out_grow( uint len ) {
   639   assert(!is_top(), "cannot grow a top node's out array");
   640   Arena* arena = Compile::current()->node_arena();
   641   uint new_max = _outmax;
   642   if( new_max == 0 ) {
   643     _outmax = 4;
   644     _out = (Node **)arena->Amalloc(4*sizeof(Node*));
   645     return;
   646   }
   647   while( new_max <= len ) new_max <<= 1; // Find next power-of-2
   648   // Trimming to limit allows a uint8 to handle up to 255 edges.
   649   // Previously I was using only powers-of-2 which peaked at 128 edges.
   650   //if( new_max >= limit ) new_max = limit-1;
   651   assert(_out != NULL && _out != NO_OUT_ARRAY, "out must have sensible value");
   652   _out = (Node**)arena->Arealloc(_out,_outmax*sizeof(Node*),new_max*sizeof(Node*));
   653   //Copy::zero_to_bytes(&_out[_outmax], (new_max-_outmax)*sizeof(Node*)); // NULL all new space
   654   _outmax = new_max;               // Record new max length
   655   // This assertion makes sure that Node::_max is wide enough to
   656   // represent the numerical value of new_max.
   657   assert(_outmax == new_max && _outmax > len, "int width of _outmax is too small");
   658 }
   660 #ifdef ASSERT
   661 //------------------------------is_dead----------------------------------------
   662 bool Node::is_dead() const {
   663   // Mach and pinch point nodes may look like dead.
   664   if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
   665     return false;
   666   for( uint i = 0; i < _max; i++ )
   667     if( _in[i] != NULL )
   668       return false;
   669   dump();
   670   return true;
   671 }
   672 #endif
   674 //------------------------------add_req----------------------------------------
   675 // Add a new required input at the end
   676 void Node::add_req( Node *n ) {
   677   assert( is_not_dead(n), "can not use dead node");
   679   // Look to see if I can move precedence down one without reallocating
   680   if( (_cnt >= _max) || (in(_max-1) != NULL) )
   681     grow( _max+1 );
   683   // Find a precedence edge to move
   684   if( in(_cnt) != NULL ) {       // Next precedence edge is busy?
   685     uint i;
   686     for( i=_cnt; i<_max; i++ )
   687       if( in(i) == NULL )       // Find the NULL at end of prec edge list
   688         break;                  // There must be one, since we grew the array
   689     _in[i] = in(_cnt);          // Move prec over, making space for req edge
   690   }
   691   _in[_cnt++] = n;            // Stuff over old prec edge
   692   if (n != NULL) n->add_out((Node *)this);
   693 }
   695 //---------------------------add_req_batch-------------------------------------
   696 // Add a new required input at the end
   697 void Node::add_req_batch( Node *n, uint m ) {
   698   assert( is_not_dead(n), "can not use dead node");
   699   // check various edge cases
   700   if ((int)m <= 1) {
   701     assert((int)m >= 0, "oob");
   702     if (m != 0)  add_req(n);
   703     return;
   704   }
   706   // Look to see if I can move precedence down one without reallocating
   707   if( (_cnt+m) > _max || _in[_max-m] )
   708     grow( _max+m );
   710   // Find a precedence edge to move
   711   if( _in[_cnt] != NULL ) {     // Next precedence edge is busy?
   712     uint i;
   713     for( i=_cnt; i<_max; i++ )
   714       if( _in[i] == NULL )      // Find the NULL at end of prec edge list
   715         break;                  // There must be one, since we grew the array
   716     // Slide all the precs over by m positions (assume #prec << m).
   717     Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
   718   }
   720   // Stuff over the old prec edges
   721   for(uint i=0; i<m; i++ ) {
   722     _in[_cnt++] = n;
   723   }
   725   // Insert multiple out edges on the node.
   726   if (n != NULL && !n->is_top()) {
   727     for(uint i=0; i<m; i++ ) {
   728       n->add_out((Node *)this);
   729     }
   730   }
   731 }
   733 //------------------------------del_req----------------------------------------
   734 // Delete the required edge and compact the edge array
   735 void Node::del_req( uint idx ) {
   736   // First remove corresponding def-use edge
   737   Node *n = in(idx);
   738   if (n != NULL) n->del_out((Node *)this);
   739   _in[idx] = in(--_cnt);  // Compact the array
   740   _in[_cnt] = NULL;       // NULL out emptied slot
   741 }
   743 //------------------------------ins_req----------------------------------------
   744 // Insert a new required input at the end
   745 void Node::ins_req( uint idx, Node *n ) {
   746   assert( is_not_dead(n), "can not use dead node");
   747   add_req(NULL);                // Make space
   748   assert( idx < _max, "Must have allocated enough space");
   749   // Slide over
   750   if(_cnt-idx-1 > 0) {
   751     Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
   752   }
   753   _in[idx] = n;                            // Stuff over old required edge
   754   if (n != NULL) n->add_out((Node *)this); // Add reciprocal def-use edge
   755 }
   757 //-----------------------------find_edge---------------------------------------
   758 int Node::find_edge(Node* n) {
   759   for (uint i = 0; i < len(); i++) {
   760     if (_in[i] == n)  return i;
   761   }
   762   return -1;
   763 }
   765 //----------------------------replace_edge-------------------------------------
   766 int Node::replace_edge(Node* old, Node* neww) {
   767   if (old == neww)  return 0;  // nothing to do
   768   uint nrep = 0;
   769   for (uint i = 0; i < len(); i++) {
   770     if (in(i) == old) {
   771       if (i < req())
   772         set_req(i, neww);
   773       else
   774         set_prec(i, neww);
   775       nrep++;
   776     }
   777   }
   778   return nrep;
   779 }
   781 //-------------------------disconnect_inputs-----------------------------------
   782 // NULL out all inputs to eliminate incoming Def-Use edges.
   783 // Return the number of edges between 'n' and 'this'
   784 int Node::disconnect_inputs(Node *n) {
   785   int edges_to_n = 0;
   787   uint cnt = req();
   788   for( uint i = 0; i < cnt; ++i ) {
   789     if( in(i) == 0 ) continue;
   790     if( in(i) == n ) ++edges_to_n;
   791     set_req(i, NULL);
   792   }
   793   // Remove precedence edges if any exist
   794   // Note: Safepoints may have precedence edges, even during parsing
   795   if( (req() != len()) && (in(req()) != NULL) ) {
   796     uint max = len();
   797     for( uint i = 0; i < max; ++i ) {
   798       if( in(i) == 0 ) continue;
   799       if( in(i) == n ) ++edges_to_n;
   800       set_prec(i, NULL);
   801     }
   802   }
   804   // Node::destruct requires all out edges be deleted first
   805   // debug_only(destruct();)   // no reuse benefit expected
   806   return edges_to_n;
   807 }
   809 //-----------------------------uncast---------------------------------------
   810 // %%% Temporary, until we sort out CheckCastPP vs. CastPP.
   811 // Strip away casting.  (It is depth-limited.)
   812 Node* Node::uncast() const {
   813   // Should be inline:
   814   //return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
   815   if (is_ConstraintCast() || is_CheckCastPP())
   816     return uncast_helper(this);
   817   else
   818     return (Node*) this;
   819 }
   821 //---------------------------uncast_helper-------------------------------------
   822 Node* Node::uncast_helper(const Node* p) {
   823   uint max_depth = 3;
   824   for (uint i = 0; i < max_depth; i++) {
   825     if (p == NULL || p->req() != 2) {
   826       break;
   827     } else if (p->is_ConstraintCast()) {
   828       p = p->in(1);
   829     } else if (p->is_CheckCastPP()) {
   830       p = p->in(1);
   831     } else {
   832       break;
   833     }
   834   }
   835   return (Node*) p;
   836 }
   838 //------------------------------add_prec---------------------------------------
   839 // Add a new precedence input.  Precedence inputs are unordered, with
   840 // duplicates removed and NULLs packed down at the end.
   841 void Node::add_prec( Node *n ) {
   842   assert( is_not_dead(n), "can not use dead node");
   844   // Check for NULL at end
   845   if( _cnt >= _max || in(_max-1) )
   846     grow( _max+1 );
   848   // Find a precedence edge to move
   849   uint i = _cnt;
   850   while( in(i) != NULL ) i++;
   851   _in[i] = n;                                // Stuff prec edge over NULL
   852   if ( n != NULL) n->add_out((Node *)this);  // Add mirror edge
   853 }
   855 //------------------------------rm_prec----------------------------------------
   856 // Remove a precedence input.  Precedence inputs are unordered, with
   857 // duplicates removed and NULLs packed down at the end.
   858 void Node::rm_prec( uint j ) {
   860   // Find end of precedence list to pack NULLs
   861   uint i;
   862   for( i=j; i<_max; i++ )
   863     if( !_in[i] )               // Find the NULL at end of prec edge list
   864       break;
   865   if (_in[j] != NULL) _in[j]->del_out((Node *)this);
   866   _in[j] = _in[--i];            // Move last element over removed guy
   867   _in[i] = NULL;                // NULL out last element
   868 }
   870 //------------------------------size_of----------------------------------------
   871 uint Node::size_of() const { return sizeof(*this); }
   873 //------------------------------ideal_reg--------------------------------------
   874 uint Node::ideal_reg() const { return 0; }
   876 //------------------------------jvms-------------------------------------------
   877 JVMState* Node::jvms() const { return NULL; }
   879 #ifdef ASSERT
   880 //------------------------------jvms-------------------------------------------
   881 bool Node::verify_jvms(const JVMState* using_jvms) const {
   882   for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
   883     if (jvms == using_jvms)  return true;
   884   }
   885   return false;
   886 }
   888 //------------------------------init_NodeProperty------------------------------
   889 void Node::init_NodeProperty() {
   890   assert(_max_classes <= max_jushort, "too many NodeProperty classes");
   891   assert(_max_flags <= max_jushort, "too many NodeProperty flags");
   892 }
   893 #endif
   895 //------------------------------format-----------------------------------------
   896 // Print as assembly
   897 void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
   898 //------------------------------emit-------------------------------------------
   899 // Emit bytes starting at parameter 'ptr'.
   900 void Node::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const {}
   901 //------------------------------size-------------------------------------------
   902 // Size of instruction in bytes
   903 uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
   905 //------------------------------CFG Construction-------------------------------
   906 // Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
   907 // Goto and Return.
   908 const Node *Node::is_block_proj() const { return 0; }
   910 // Minimum guaranteed type
   911 const Type *Node::bottom_type() const { return Type::BOTTOM; }
   914 //------------------------------raise_bottom_type------------------------------
   915 // Get the worst-case Type output for this Node.
   916 void Node::raise_bottom_type(const Type* new_type) {
   917   if (is_Type()) {
   918     TypeNode *n = this->as_Type();
   919     if (VerifyAliases) {
   920       assert(new_type->higher_equal(n->type()), "new type must refine old type");
   921     }
   922     n->set_type(new_type);
   923   } else if (is_Load()) {
   924     LoadNode *n = this->as_Load();
   925     if (VerifyAliases) {
   926       assert(new_type->higher_equal(n->type()), "new type must refine old type");
   927     }
   928     n->set_type(new_type);
   929   }
   930 }
   932 //------------------------------Identity---------------------------------------
   933 // Return a node that the given node is equivalent to.
   934 Node *Node::Identity( PhaseTransform * ) {
   935   return this;                  // Default to no identities
   936 }
   938 //------------------------------Value------------------------------------------
   939 // Compute a new Type for a node using the Type of the inputs.
   940 const Type *Node::Value( PhaseTransform * ) const {
   941   return bottom_type();         // Default to worst-case Type
   942 }
   944 //------------------------------Ideal------------------------------------------
   945 //
   946 // 'Idealize' the graph rooted at this Node.
   947 //
   948 // In order to be efficient and flexible there are some subtle invariants
   949 // these Ideal calls need to hold.  Running with '+VerifyIterativeGVN' checks
   950 // these invariants, although its too slow to have on by default.  If you are
   951 // hacking an Ideal call, be sure to test with +VerifyIterativeGVN!
   952 //
   953 // The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
   954 // pointer.  If ANY change is made, it must return the root of the reshaped
   955 // graph - even if the root is the same Node.  Example: swapping the inputs
   956 // to an AddINode gives the same answer and same root, but you still have to
   957 // return the 'this' pointer instead of NULL.
   958 //
   959 // You cannot return an OLD Node, except for the 'this' pointer.  Use the
   960 // Identity call to return an old Node; basically if Identity can find
   961 // another Node have the Ideal call make no change and return NULL.
   962 // Example: AddINode::Ideal must check for add of zero; in this case it
   963 // returns NULL instead of doing any graph reshaping.
   964 //
   965 // You cannot modify any old Nodes except for the 'this' pointer.  Due to
   966 // sharing there may be other users of the old Nodes relying on their current
   967 // semantics.  Modifying them will break the other users.
   968 // Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
   969 // "X+3" unchanged in case it is shared.
   970 //
   971 // If you modify the 'this' pointer's inputs, you should use
   972 // 'set_req'.  If you are making a new Node (either as the new root or
   973 // some new internal piece) you may use 'init_req' to set the initial
   974 // value.  You can make a new Node with either 'new' or 'clone'.  In
   975 // either case, def-use info is correctly maintained.
   976 //
   977 // Example: reshape "(X+3)+4" into "X+7":
   978 //    set_req(1, in(1)->in(1));
   979 //    set_req(2, phase->intcon(7));
   980 //    return this;
   981 // Example: reshape "X*4" into "X<<2"
   982 //    return new (C,3) LShiftINode(in(1), phase->intcon(2));
   983 //
   984 // You must call 'phase->transform(X)' on any new Nodes X you make, except
   985 // for the returned root node.  Example: reshape "X*31" with "(X<<5)-X".
   986 //    Node *shift=phase->transform(new(C,3)LShiftINode(in(1),phase->intcon(5)));
   987 //    return new (C,3) AddINode(shift, in(1));
   988 //
   989 // When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
   990 // These forms are faster than 'phase->transform(new (C,1) ConNode())' and Do
   991 // The Right Thing with def-use info.
   992 //
   993 // You cannot bury the 'this' Node inside of a graph reshape.  If the reshaped
   994 // graph uses the 'this' Node it must be the root.  If you want a Node with
   995 // the same Opcode as the 'this' pointer use 'clone'.
   996 //
   997 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
   998   return NULL;                  // Default to being Ideal already
   999 }
  1001 // Some nodes have specific Ideal subgraph transformations only if they are
  1002 // unique users of specific nodes. Such nodes should be put on IGVN worklist
  1003 // for the transformations to happen.
  1004 bool Node::has_special_unique_user() const {
  1005   assert(outcnt() == 1, "match only for unique out");
  1006   Node* n = unique_out();
  1007   int op  = Opcode();
  1008   if( this->is_Store() ) {
  1009     // Condition for back-to-back stores folding.
  1010     return n->Opcode() == op && n->in(MemNode::Memory) == this;
  1011   } else if( op == Op_AddL ) {
  1012     // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
  1013     return n->Opcode() == Op_ConvL2I && n->in(1) == this;
  1014   } else if( op == Op_SubI || op == Op_SubL ) {
  1015     // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
  1016     return n->Opcode() == op && n->in(2) == this;
  1018   return false;
  1019 };
  1021 //--------------------------find_exact_control---------------------------------
  1022 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
  1023 Node* Node::find_exact_control(Node* ctrl) {
  1024   if (ctrl == NULL && this->is_Region())
  1025     ctrl = this->as_Region()->is_copy();
  1027   if (ctrl != NULL && ctrl->is_CatchProj()) {
  1028     if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
  1029       ctrl = ctrl->in(0);
  1030     if (ctrl != NULL && !ctrl->is_top())
  1031       ctrl = ctrl->in(0);
  1034   if (ctrl != NULL && ctrl->is_Proj())
  1035     ctrl = ctrl->in(0);
  1037   return ctrl;
  1040 //--------------------------dominates------------------------------------------
  1041 // Helper function for MemNode::all_controls_dominate().
  1042 // Check if 'this' control node dominates or equal to 'sub' control node.
  1043 // We already know that if any path back to Root or Start reaches 'this',
  1044 // then all paths so, so this is a simple search for one example,
  1045 // not an exhaustive search for a counterexample.
  1046 bool Node::dominates(Node* sub, Node_List &nlist) {
  1047   assert(this->is_CFG(), "expecting control");
  1048   assert(sub != NULL && sub->is_CFG(), "expecting control");
  1050   // detect dead cycle without regions
  1051   int iterations_without_region_limit = DominatorSearchLimit;
  1053   Node* orig_sub = sub;
  1054   Node* dom      = this;
  1055   bool  met_dom  = false;
  1056   nlist.clear();
  1058   // Walk 'sub' backward up the chain to 'dom', watching for regions.
  1059   // After seeing 'dom', continue up to Root or Start.
  1060   // If we hit a region (backward split point), it may be a loop head.
  1061   // Keep going through one of the region's inputs.  If we reach the
  1062   // same region again, go through a different input.  Eventually we
  1063   // will either exit through the loop head, or give up.
  1064   // (If we get confused, break out and return a conservative 'false'.)
  1065   while (sub != NULL) {
  1066     if (sub->is_top())  break; // Conservative answer for dead code.
  1067     if (sub == dom) {
  1068       if (nlist.size() == 0) {
  1069         // No Region nodes except loops were visited before and the EntryControl
  1070         // path was taken for loops: it did not walk in a cycle.
  1071         return true;
  1072       } else if (met_dom) {
  1073         break;          // already met before: walk in a cycle
  1074       } else {
  1075         // Region nodes were visited. Continue walk up to Start or Root
  1076         // to make sure that it did not walk in a cycle.
  1077         met_dom = true; // first time meet
  1078         iterations_without_region_limit = DominatorSearchLimit; // Reset
  1081     if (sub->is_Start() || sub->is_Root()) {
  1082       // Success if we met 'dom' along a path to Start or Root.
  1083       // We assume there are no alternative paths that avoid 'dom'.
  1084       // (This assumption is up to the caller to ensure!)
  1085       return met_dom;
  1087     Node* up = sub->in(0);
  1088     // Normalize simple pass-through regions and projections:
  1089     up = sub->find_exact_control(up);
  1090     // If sub == up, we found a self-loop.  Try to push past it.
  1091     if (sub == up && sub->is_Loop()) {
  1092       // Take loop entry path on the way up to 'dom'.
  1093       up = sub->in(1); // in(LoopNode::EntryControl);
  1094     } else if (sub == up && sub->is_Region() && sub->req() != 3) {
  1095       // Always take in(1) path on the way up to 'dom' for clone regions
  1096       // (with only one input) or regions which merge > 2 paths
  1097       // (usually used to merge fast/slow paths).
  1098       up = sub->in(1);
  1099     } else if (sub == up && sub->is_Region()) {
  1100       // Try both paths for Regions with 2 input paths (it may be a loop head).
  1101       // It could give conservative 'false' answer without information
  1102       // which region's input is the entry path.
  1103       iterations_without_region_limit = DominatorSearchLimit; // Reset
  1105       bool region_was_visited_before = false;
  1106       // Was this Region node visited before?
  1107       // If so, we have reached it because we accidentally took a
  1108       // loop-back edge from 'sub' back into the body of the loop,
  1109       // and worked our way up again to the loop header 'sub'.
  1110       // So, take the first unexplored path on the way up to 'dom'.
  1111       for (int j = nlist.size() - 1; j >= 0; j--) {
  1112         intptr_t ni = (intptr_t)nlist.at(j);
  1113         Node* visited = (Node*)(ni & ~1);
  1114         bool  visited_twice_already = ((ni & 1) != 0);
  1115         if (visited == sub) {
  1116           if (visited_twice_already) {
  1117             // Visited 2 paths, but still stuck in loop body.  Give up.
  1118             return false;
  1120           // The Region node was visited before only once.
  1121           // (We will repush with the low bit set, below.)
  1122           nlist.remove(j);
  1123           // We will find a new edge and re-insert.
  1124           region_was_visited_before = true;
  1125           break;
  1129       // Find an incoming edge which has not been seen yet; walk through it.
  1130       assert(up == sub, "");
  1131       uint skip = region_was_visited_before ? 1 : 0;
  1132       for (uint i = 1; i < sub->req(); i++) {
  1133         Node* in = sub->in(i);
  1134         if (in != NULL && !in->is_top() && in != sub) {
  1135           if (skip == 0) {
  1136             up = in;
  1137             break;
  1139           --skip;               // skip this nontrivial input
  1143       // Set 0 bit to indicate that both paths were taken.
  1144       nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
  1147     if (up == sub) {
  1148       break;    // some kind of tight cycle
  1150     if (up == orig_sub && met_dom) {
  1151       // returned back after visiting 'dom'
  1152       break;    // some kind of cycle
  1154     if (--iterations_without_region_limit < 0) {
  1155       break;    // dead cycle
  1157     sub = up;
  1160   // Did not meet Root or Start node in pred. chain.
  1161   // Conservative answer for dead code.
  1162   return false;
  1165 //------------------------------remove_dead_region-----------------------------
  1166 // This control node is dead.  Follow the subgraph below it making everything
  1167 // using it dead as well.  This will happen normally via the usual IterGVN
  1168 // worklist but this call is more efficient.  Do not update use-def info
  1169 // inside the dead region, just at the borders.
  1170 static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
  1171   // Con's are a popular node to re-hit in the hash table again.
  1172   if( dead->is_Con() ) return;
  1174   // Can't put ResourceMark here since igvn->_worklist uses the same arena
  1175   // for verify pass with +VerifyOpto and we add/remove elements in it here.
  1176   Node_List  nstack(Thread::current()->resource_area());
  1178   Node *top = igvn->C->top();
  1179   nstack.push(dead);
  1181   while (nstack.size() > 0) {
  1182     dead = nstack.pop();
  1183     if (dead->outcnt() > 0) {
  1184       // Keep dead node on stack until all uses are processed.
  1185       nstack.push(dead);
  1186       // For all Users of the Dead...    ;-)
  1187       for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
  1188         Node* use = dead->last_out(k);
  1189         igvn->hash_delete(use);       // Yank from hash table prior to mod
  1190         if (use->in(0) == dead) {     // Found another dead node
  1191           assert (!use->is_Con(), "Control for Con node should be Root node.")
  1192           use->set_req(0, top);       // Cut dead edge to prevent processing
  1193           nstack.push(use);           // the dead node again.
  1194         } else {                      // Else found a not-dead user
  1195           for (uint j = 1; j < use->req(); j++) {
  1196             if (use->in(j) == dead) { // Turn all dead inputs into TOP
  1197               use->set_req(j, top);
  1200           igvn->_worklist.push(use);
  1202         // Refresh the iterator, since any number of kills might have happened.
  1203         k = dead->last_outs(kmin);
  1205     } else { // (dead->outcnt() == 0)
  1206       // Done with outputs.
  1207       igvn->hash_delete(dead);
  1208       igvn->_worklist.remove(dead);
  1209       igvn->set_type(dead, Type::TOP);
  1210       if (dead->is_macro()) {
  1211         igvn->C->remove_macro_node(dead);
  1213       // Kill all inputs to the dead guy
  1214       for (uint i=0; i < dead->req(); i++) {
  1215         Node *n = dead->in(i);      // Get input to dead guy
  1216         if (n != NULL && !n->is_top()) { // Input is valid?
  1217           dead->set_req(i, top);    // Smash input away
  1218           if (n->outcnt() == 0) {   // Input also goes dead?
  1219             if (!n->is_Con())
  1220               nstack.push(n);       // Clear it out as well
  1221           } else if (n->outcnt() == 1 &&
  1222                      n->has_special_unique_user()) {
  1223             igvn->add_users_to_worklist( n );
  1224           } else if (n->outcnt() <= 2 && n->is_Store()) {
  1225             // Push store's uses on worklist to enable folding optimization for
  1226             // store/store and store/load to the same address.
  1227             // The restriction (outcnt() <= 2) is the same as in set_req_X()
  1228             // and remove_globally_dead_node().
  1229             igvn->add_users_to_worklist( n );
  1233     } // (dead->outcnt() == 0)
  1234   }   // while (nstack.size() > 0) for outputs
  1235   return;
  1238 //------------------------------remove_dead_region-----------------------------
  1239 bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
  1240   Node *n = in(0);
  1241   if( !n ) return false;
  1242   // Lost control into this guy?  I.e., it became unreachable?
  1243   // Aggressively kill all unreachable code.
  1244   if (can_reshape && n->is_top()) {
  1245     kill_dead_code(this, phase->is_IterGVN());
  1246     return false; // Node is dead.
  1249   if( n->is_Region() && n->as_Region()->is_copy() ) {
  1250     Node *m = n->nonnull_req();
  1251     set_req(0, m);
  1252     return true;
  1254   return false;
  1257 //------------------------------Ideal_DU_postCCP-------------------------------
  1258 // Idealize graph, using DU info.  Must clone result into new-space
  1259 Node *Node::Ideal_DU_postCCP( PhaseCCP * ) {
  1260   return NULL;                 // Default to no change
  1263 //------------------------------hash-------------------------------------------
  1264 // Hash function over Nodes.
  1265 uint Node::hash() const {
  1266   uint sum = 0;
  1267   for( uint i=0; i<_cnt; i++ )  // Add in all inputs
  1268     sum = (sum<<1)-(uintptr_t)in(i);        // Ignore embedded NULLs
  1269   return (sum>>2) + _cnt + Opcode();
  1272 //------------------------------cmp--------------------------------------------
  1273 // Compare special parts of simple Nodes
  1274 uint Node::cmp( const Node &n ) const {
  1275   return 1;                     // Must be same
  1278 //------------------------------rematerialize-----------------------------------
  1279 // Should we clone rather than spill this instruction?
  1280 bool Node::rematerialize() const {
  1281   if ( is_Mach() )
  1282     return this->as_Mach()->rematerialize();
  1283   else
  1284     return (_flags & Flag_rematerialize) != 0;
  1287 //------------------------------needs_anti_dependence_check---------------------
  1288 // Nodes which use memory without consuming it, hence need antidependences.
  1289 bool Node::needs_anti_dependence_check() const {
  1290   if( req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0 )
  1291     return false;
  1292   else
  1293     return in(1)->bottom_type()->has_memory();
  1297 // Get an integer constant from a ConNode (or CastIINode).
  1298 // Return a default value if there is no apparent constant here.
  1299 const TypeInt* Node::find_int_type() const {
  1300   if (this->is_Type()) {
  1301     return this->as_Type()->type()->isa_int();
  1302   } else if (this->is_Con()) {
  1303     assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
  1304     return this->bottom_type()->isa_int();
  1306   return NULL;
  1309 // Get a pointer constant from a ConstNode.
  1310 // Returns the constant if it is a pointer ConstNode
  1311 intptr_t Node::get_ptr() const {
  1312   assert( Opcode() == Op_ConP, "" );
  1313   return ((ConPNode*)this)->type()->is_ptr()->get_con();
  1316 // Get a narrow oop constant from a ConNNode.
  1317 intptr_t Node::get_narrowcon() const {
  1318   assert( Opcode() == Op_ConN, "" );
  1319   return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
  1322 // Get a long constant from a ConNode.
  1323 // Return a default value if there is no apparent constant here.
  1324 const TypeLong* Node::find_long_type() const {
  1325   if (this->is_Type()) {
  1326     return this->as_Type()->type()->isa_long();
  1327   } else if (this->is_Con()) {
  1328     assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
  1329     return this->bottom_type()->isa_long();
  1331   return NULL;
  1334 // Get a double constant from a ConstNode.
  1335 // Returns the constant if it is a double ConstNode
  1336 jdouble Node::getd() const {
  1337   assert( Opcode() == Op_ConD, "" );
  1338   return ((ConDNode*)this)->type()->is_double_constant()->getd();
  1341 // Get a float constant from a ConstNode.
  1342 // Returns the constant if it is a float ConstNode
  1343 jfloat Node::getf() const {
  1344   assert( Opcode() == Op_ConF, "" );
  1345   return ((ConFNode*)this)->type()->is_float_constant()->getf();
  1348 #ifndef PRODUCT
  1350 //----------------------------NotANode----------------------------------------
  1351 // Used in debugging code to avoid walking across dead or uninitialized edges.
  1352 static inline bool NotANode(const Node* n) {
  1353   if (n == NULL)                   return true;
  1354   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
  1355   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
  1356   return false;
  1360 //------------------------------find------------------------------------------
  1361 // Find a neighbor of this Node with the given _idx
  1362 // If idx is negative, find its absolute value, following both _in and _out.
  1363 static void find_recur( Node* &result, Node *n, int idx, bool only_ctrl,
  1364                         VectorSet &old_space, VectorSet &new_space ) {
  1365   int node_idx = (idx >= 0) ? idx : -idx;
  1366   if (NotANode(n))  return;  // Gracefully handle NULL, -1, 0xabababab, etc.
  1367   // Contained in new_space or old_space?
  1368   VectorSet *v = Compile::current()->node_arena()->contains(n) ? &new_space : &old_space;
  1369   if( v->test(n->_idx) ) return;
  1370   if( (int)n->_idx == node_idx
  1371       debug_only(|| n->debug_idx() == node_idx) ) {
  1372     if (result != NULL)
  1373       tty->print("find: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
  1374                  (uintptr_t)result, (uintptr_t)n, node_idx);
  1375     result = n;
  1377   v->set(n->_idx);
  1378   for( uint i=0; i<n->len(); i++ ) {
  1379     if( only_ctrl && !(n->is_Region()) && (n->Opcode() != Op_Root) && (i != TypeFunc::Control) ) continue;
  1380     find_recur( result, n->in(i), idx, only_ctrl, old_space, new_space );
  1382   // Search along forward edges also:
  1383   if (idx < 0 && !only_ctrl) {
  1384     for( uint j=0; j<n->outcnt(); j++ ) {
  1385       find_recur( result, n->raw_out(j), idx, only_ctrl, old_space, new_space );
  1388 #ifdef ASSERT
  1389   // Search along debug_orig edges last:
  1390   for (Node* orig = n->debug_orig(); orig != NULL && n != orig; orig = orig->debug_orig()) {
  1391     if (NotANode(orig))  break;
  1392     find_recur( result, orig, idx, only_ctrl, old_space, new_space );
  1394 #endif //ASSERT
  1397 // call this from debugger:
  1398 Node* find_node(Node* n, int idx) {
  1399   return n->find(idx);
  1402 //------------------------------find-------------------------------------------
  1403 Node* Node::find(int idx) const {
  1404   ResourceArea *area = Thread::current()->resource_area();
  1405   VectorSet old_space(area), new_space(area);
  1406   Node* result = NULL;
  1407   find_recur( result, (Node*) this, idx, false, old_space, new_space );
  1408   return result;
  1411 //------------------------------find_ctrl--------------------------------------
  1412 // Find an ancestor to this node in the control history with given _idx
  1413 Node* Node::find_ctrl(int idx) const {
  1414   ResourceArea *area = Thread::current()->resource_area();
  1415   VectorSet old_space(area), new_space(area);
  1416   Node* result = NULL;
  1417   find_recur( result, (Node*) this, idx, true, old_space, new_space );
  1418   return result;
  1420 #endif
  1424 #ifndef PRODUCT
  1425 int Node::_in_dump_cnt = 0;
  1427 // -----------------------------Name-------------------------------------------
  1428 extern const char *NodeClassNames[];
  1429 const char *Node::Name() const { return NodeClassNames[Opcode()]; }
  1431 static bool is_disconnected(const Node* n) {
  1432   for (uint i = 0; i < n->req(); i++) {
  1433     if (n->in(i) != NULL)  return false;
  1435   return true;
  1438 #ifdef ASSERT
  1439 static void dump_orig(Node* orig) {
  1440   Compile* C = Compile::current();
  1441   if (NotANode(orig))  orig = NULL;
  1442   if (orig != NULL && !C->node_arena()->contains(orig))  orig = NULL;
  1443   if (orig == NULL)  return;
  1444   tty->print(" !orig=");
  1445   Node* fast = orig->debug_orig(); // tortoise & hare algorithm to detect loops
  1446   if (NotANode(fast))  fast = NULL;
  1447   while (orig != NULL) {
  1448     bool discon = is_disconnected(orig);  // if discon, print [123] else 123
  1449     if (discon)  tty->print("[");
  1450     if (!Compile::current()->node_arena()->contains(orig))
  1451       tty->print("o");
  1452     tty->print("%d", orig->_idx);
  1453     if (discon)  tty->print("]");
  1454     orig = orig->debug_orig();
  1455     if (NotANode(orig))  orig = NULL;
  1456     if (orig != NULL && !C->node_arena()->contains(orig))  orig = NULL;
  1457     if (orig != NULL)  tty->print(",");
  1458     if (fast != NULL) {
  1459       // Step fast twice for each single step of orig:
  1460       fast = fast->debug_orig();
  1461       if (NotANode(fast))  fast = NULL;
  1462       if (fast != NULL && fast != orig) {
  1463         fast = fast->debug_orig();
  1464         if (NotANode(fast))  fast = NULL;
  1466       if (fast == orig) {
  1467         tty->print("...");
  1468         break;
  1474 void Node::set_debug_orig(Node* orig) {
  1475   _debug_orig = orig;
  1476   if (BreakAtNode == 0)  return;
  1477   if (NotANode(orig))  orig = NULL;
  1478   int trip = 10;
  1479   while (orig != NULL) {
  1480     if (orig->debug_idx() == BreakAtNode || (int)orig->_idx == BreakAtNode) {
  1481       tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d orig._idx=%d orig._debug_idx=%d",
  1482                     this->_idx, this->debug_idx(), orig->_idx, orig->debug_idx());
  1483       BREAKPOINT;
  1485     orig = orig->debug_orig();
  1486     if (NotANode(orig))  orig = NULL;
  1487     if (trip-- <= 0)  break;
  1490 #endif //ASSERT
  1492 //------------------------------dump------------------------------------------
  1493 // Dump a Node
  1494 void Node::dump() const {
  1495   Compile* C = Compile::current();
  1496   bool is_new = C->node_arena()->contains(this);
  1497   _in_dump_cnt++;
  1498   tty->print("%c%d\t%s\t=== ",
  1499              is_new ? ' ' : 'o', _idx, Name());
  1501   // Dump the required and precedence inputs
  1502   dump_req();
  1503   dump_prec();
  1504   // Dump the outputs
  1505   dump_out();
  1507   if (is_disconnected(this)) {
  1508 #ifdef ASSERT
  1509     tty->print("  [%d]",debug_idx());
  1510     dump_orig(debug_orig());
  1511 #endif
  1512     tty->cr();
  1513     _in_dump_cnt--;
  1514     return;                     // don't process dead nodes
  1517   // Dump node-specific info
  1518   dump_spec(tty);
  1519 #ifdef ASSERT
  1520   // Dump the non-reset _debug_idx
  1521   if( Verbose && WizardMode ) {
  1522     tty->print("  [%d]",debug_idx());
  1524 #endif
  1526   const Type *t = bottom_type();
  1528   if (t != NULL && (t->isa_instptr() || t->isa_klassptr())) {
  1529     const TypeInstPtr  *toop = t->isa_instptr();
  1530     const TypeKlassPtr *tkls = t->isa_klassptr();
  1531     ciKlass*           klass = toop ? toop->klass() : (tkls ? tkls->klass() : NULL );
  1532     if( klass && klass->is_loaded() && klass->is_interface() ) {
  1533       tty->print("  Interface:");
  1534     } else if( toop ) {
  1535       tty->print("  Oop:");
  1536     } else if( tkls ) {
  1537       tty->print("  Klass:");
  1539     t->dump();
  1540   } else if( t == Type::MEMORY ) {
  1541     tty->print("  Memory:");
  1542     MemNode::dump_adr_type(this, adr_type(), tty);
  1543   } else if( Verbose || WizardMode ) {
  1544     tty->print("  Type:");
  1545     if( t ) {
  1546       t->dump();
  1547     } else {
  1548       tty->print("no type");
  1551   if (is_new) {
  1552     debug_only(dump_orig(debug_orig()));
  1553     Node_Notes* nn = C->node_notes_at(_idx);
  1554     if (nn != NULL && !nn->is_clear()) {
  1555       if (nn->jvms() != NULL) {
  1556         tty->print(" !jvms:");
  1557         nn->jvms()->dump_spec(tty);
  1561   tty->cr();
  1562   _in_dump_cnt--;
  1565 //------------------------------dump_req--------------------------------------
  1566 void Node::dump_req() const {
  1567   // Dump the required input edges
  1568   for (uint i = 0; i < req(); i++) {    // For all required inputs
  1569     Node* d = in(i);
  1570     if (d == NULL) {
  1571       tty->print("_ ");
  1572     } else if (NotANode(d)) {
  1573       tty->print("NotANode ");  // uninitialized, sentinel, garbage, etc.
  1574     } else {
  1575       tty->print("%c%d ", Compile::current()->node_arena()->contains(d) ? ' ' : 'o', d->_idx);
  1581 //------------------------------dump_prec-------------------------------------
  1582 void Node::dump_prec() const {
  1583   // Dump the precedence edges
  1584   int any_prec = 0;
  1585   for (uint i = req(); i < len(); i++) {       // For all precedence inputs
  1586     Node* p = in(i);
  1587     if (p != NULL) {
  1588       if( !any_prec++ ) tty->print(" |");
  1589       if (NotANode(p)) { tty->print("NotANode "); continue; }
  1590       tty->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
  1595 //------------------------------dump_out--------------------------------------
  1596 void Node::dump_out() const {
  1597   // Delimit the output edges
  1598   tty->print(" [[");
  1599   // Dump the output edges
  1600   for (uint i = 0; i < _outcnt; i++) {    // For all outputs
  1601     Node* u = _out[i];
  1602     if (u == NULL) {
  1603       tty->print("_ ");
  1604     } else if (NotANode(u)) {
  1605       tty->print("NotANode ");
  1606     } else {
  1607       tty->print("%c%d ", Compile::current()->node_arena()->contains(u) ? ' ' : 'o', u->_idx);
  1610   tty->print("]] ");
  1613 //------------------------------dump_nodes-------------------------------------
  1614 static void dump_nodes(const Node* start, int d, bool only_ctrl) {
  1615   Node* s = (Node*)start; // remove const
  1616   if (NotANode(s)) return;
  1618   uint depth = (uint)ABS(d);
  1619   int direction = d;
  1620   Compile* C = Compile::current();
  1621   GrowableArray <Node *> nstack(C->unique());
  1623   nstack.append(s);
  1624   int begin = 0;
  1625   int end = 0;
  1626   for(uint i = 0; i < depth; i++) {
  1627     end = nstack.length();
  1628     for(int j = begin; j < end; j++) {
  1629       Node* tp  = nstack.at(j);
  1630       uint limit = direction > 0 ? tp->len() : tp->outcnt();
  1631       for(uint k = 0; k < limit; k++) {
  1632         Node* n = direction > 0 ? tp->in(k) : tp->raw_out(k);
  1634         if (NotANode(n))  continue;
  1635         // do not recurse through top or the root (would reach unrelated stuff)
  1636         if (n->is_Root() || n->is_top())  continue;
  1637         if (only_ctrl && !n->is_CFG()) continue;
  1639         bool on_stack = nstack.contains(n);
  1640         if (!on_stack) {
  1641           nstack.append(n);
  1645     begin = end;
  1647   end = nstack.length();
  1648   if (direction > 0) {
  1649     for(int j = end-1; j >= 0; j--) {
  1650       nstack.at(j)->dump();
  1652   } else {
  1653     for(int j = 0; j < end; j++) {
  1654       nstack.at(j)->dump();
  1659 //------------------------------dump-------------------------------------------
  1660 void Node::dump(int d) const {
  1661   dump_nodes(this, d, false);
  1664 //------------------------------dump_ctrl--------------------------------------
  1665 // Dump a Node's control history to depth
  1666 void Node::dump_ctrl(int d) const {
  1667   dump_nodes(this, d, true);
  1670 // VERIFICATION CODE
  1671 // For each input edge to a node (ie - for each Use-Def edge), verify that
  1672 // there is a corresponding Def-Use edge.
  1673 //------------------------------verify_edges-----------------------------------
  1674 void Node::verify_edges(Unique_Node_List &visited) {
  1675   uint i, j, idx;
  1676   int  cnt;
  1677   Node *n;
  1679   // Recursive termination test
  1680   if (visited.member(this))  return;
  1681   visited.push(this);
  1683   // Walk over all input edges, checking for correspondence
  1684   for( i = 0; i < len(); i++ ) {
  1685     n = in(i);
  1686     if (n != NULL && !n->is_top()) {
  1687       // Count instances of (Node *)this
  1688       cnt = 0;
  1689       for (idx = 0; idx < n->_outcnt; idx++ ) {
  1690         if (n->_out[idx] == (Node *)this)  cnt++;
  1692       assert( cnt > 0,"Failed to find Def-Use edge." );
  1693       // Check for duplicate edges
  1694       // walk the input array downcounting the input edges to n
  1695       for( j = 0; j < len(); j++ ) {
  1696         if( in(j) == n ) cnt--;
  1698       assert( cnt == 0,"Mismatched edge count.");
  1699     } else if (n == NULL) {
  1700       assert(i >= req() || i == 0 || is_Region() || is_Phi(), "only regions or phis have null data edges");
  1701     } else {
  1702       assert(n->is_top(), "sanity");
  1703       // Nothing to check.
  1706   // Recursive walk over all input edges
  1707   for( i = 0; i < len(); i++ ) {
  1708     n = in(i);
  1709     if( n != NULL )
  1710       in(i)->verify_edges(visited);
  1714 //------------------------------verify_recur-----------------------------------
  1715 static const Node *unique_top = NULL;
  1717 void Node::verify_recur(const Node *n, int verify_depth,
  1718                         VectorSet &old_space, VectorSet &new_space) {
  1719   if ( verify_depth == 0 )  return;
  1720   if (verify_depth > 0)  --verify_depth;
  1722   Compile* C = Compile::current();
  1724   // Contained in new_space or old_space?
  1725   VectorSet *v = C->node_arena()->contains(n) ? &new_space : &old_space;
  1726   // Check for visited in the proper space.  Numberings are not unique
  1727   // across spaces so we need a separate VectorSet for each space.
  1728   if( v->test_set(n->_idx) ) return;
  1730   if (n->is_Con() && n->bottom_type() == Type::TOP) {
  1731     if (C->cached_top_node() == NULL)
  1732       C->set_cached_top_node((Node*)n);
  1733     assert(C->cached_top_node() == n, "TOP node must be unique");
  1736   for( uint i = 0; i < n->len(); i++ ) {
  1737     Node *x = n->in(i);
  1738     if (!x || x->is_top()) continue;
  1740     // Verify my input has a def-use edge to me
  1741     if (true /*VerifyDefUse*/) {
  1742       // Count use-def edges from n to x
  1743       int cnt = 0;
  1744       for( uint j = 0; j < n->len(); j++ )
  1745         if( n->in(j) == x )
  1746           cnt++;
  1747       // Count def-use edges from x to n
  1748       uint max = x->_outcnt;
  1749       for( uint k = 0; k < max; k++ )
  1750         if (x->_out[k] == n)
  1751           cnt--;
  1752       assert( cnt == 0, "mismatched def-use edge counts" );
  1755     verify_recur(x, verify_depth, old_space, new_space);
  1760 //------------------------------verify-----------------------------------------
  1761 // Check Def-Use info for my subgraph
  1762 void Node::verify() const {
  1763   Compile* C = Compile::current();
  1764   Node* old_top = C->cached_top_node();
  1765   ResourceMark rm;
  1766   ResourceArea *area = Thread::current()->resource_area();
  1767   VectorSet old_space(area), new_space(area);
  1768   verify_recur(this, -1, old_space, new_space);
  1769   C->set_cached_top_node(old_top);
  1771 #endif
  1774 //------------------------------walk-------------------------------------------
  1775 // Graph walk, with both pre-order and post-order functions
  1776 void Node::walk(NFunc pre, NFunc post, void *env) {
  1777   VectorSet visited(Thread::current()->resource_area()); // Setup for local walk
  1778   walk_(pre, post, env, visited);
  1781 void Node::walk_(NFunc pre, NFunc post, void *env, VectorSet &visited) {
  1782   if( visited.test_set(_idx) ) return;
  1783   pre(*this,env);               // Call the pre-order walk function
  1784   for( uint i=0; i<_max; i++ )
  1785     if( in(i) )                 // Input exists and is not walked?
  1786       in(i)->walk_(pre,post,env,visited); // Walk it with pre & post functions
  1787   post(*this,env);              // Call the post-order walk function
  1790 void Node::nop(Node &, void*) {}
  1792 //------------------------------Registers--------------------------------------
  1793 // Do we Match on this edge index or not?  Generally false for Control
  1794 // and true for everything else.  Weird for calls & returns.
  1795 uint Node::match_edge(uint idx) const {
  1796   return idx;                   // True for other than index 0 (control)
  1799 // Register classes are defined for specific machines
  1800 const RegMask &Node::out_RegMask() const {
  1801   ShouldNotCallThis();
  1802   return *(new RegMask());
  1805 const RegMask &Node::in_RegMask(uint) const {
  1806   ShouldNotCallThis();
  1807   return *(new RegMask());
  1810 //=============================================================================
  1811 //-----------------------------------------------------------------------------
  1812 void Node_Array::reset( Arena *new_arena ) {
  1813   _a->Afree(_nodes,_max*sizeof(Node*));
  1814   _max   = 0;
  1815   _nodes = NULL;
  1816   _a     = new_arena;
  1819 //------------------------------clear------------------------------------------
  1820 // Clear all entries in _nodes to NULL but keep storage
  1821 void Node_Array::clear() {
  1822   Copy::zero_to_bytes( _nodes, _max*sizeof(Node*) );
  1825 //-----------------------------------------------------------------------------
  1826 void Node_Array::grow( uint i ) {
  1827   if( !_max ) {
  1828     _max = 1;
  1829     _nodes = (Node**)_a->Amalloc( _max * sizeof(Node*) );
  1830     _nodes[0] = NULL;
  1832   uint old = _max;
  1833   while( i >= _max ) _max <<= 1;        // Double to fit
  1834   _nodes = (Node**)_a->Arealloc( _nodes, old*sizeof(Node*),_max*sizeof(Node*));
  1835   Copy::zero_to_bytes( &_nodes[old], (_max-old)*sizeof(Node*) );
  1838 //-----------------------------------------------------------------------------
  1839 void Node_Array::insert( uint i, Node *n ) {
  1840   if( _nodes[_max-1] ) grow(_max);      // Get more space if full
  1841   Copy::conjoint_words_to_higher((HeapWord*)&_nodes[i], (HeapWord*)&_nodes[i+1], ((_max-i-1)*sizeof(Node*)));
  1842   _nodes[i] = n;
  1845 //-----------------------------------------------------------------------------
  1846 void Node_Array::remove( uint i ) {
  1847   Copy::conjoint_words_to_lower((HeapWord*)&_nodes[i+1], (HeapWord*)&_nodes[i], ((_max-i-1)*sizeof(Node*)));
  1848   _nodes[_max-1] = NULL;
  1851 //-----------------------------------------------------------------------------
  1852 void Node_Array::sort( C_sort_func_t func) {
  1853   qsort( _nodes, _max, sizeof( Node* ), func );
  1856 //-----------------------------------------------------------------------------
  1857 void Node_Array::dump() const {
  1858 #ifndef PRODUCT
  1859   for( uint i = 0; i < _max; i++ ) {
  1860     Node *nn = _nodes[i];
  1861     if( nn != NULL ) {
  1862       tty->print("%5d--> ",i); nn->dump();
  1865 #endif
  1868 //--------------------------is_iteratively_computed------------------------------
  1869 // Operation appears to be iteratively computed (such as an induction variable)
  1870 // It is possible for this operation to return false for a loop-varying
  1871 // value, if it appears (by local graph inspection) to be computed by a simple conditional.
  1872 bool Node::is_iteratively_computed() {
  1873   if (ideal_reg()) { // does operation have a result register?
  1874     for (uint i = 1; i < req(); i++) {
  1875       Node* n = in(i);
  1876       if (n != NULL && n->is_Phi()) {
  1877         for (uint j = 1; j < n->req(); j++) {
  1878           if (n->in(j) == this) {
  1879             return true;
  1885   return false;
  1888 //--------------------------find_similar------------------------------
  1889 // Return a node with opcode "opc" and same inputs as "this" if one can
  1890 // be found; Otherwise return NULL;
  1891 Node* Node::find_similar(int opc) {
  1892   if (req() >= 2) {
  1893     Node* def = in(1);
  1894     if (def && def->outcnt() >= 2) {
  1895       for (DUIterator_Fast dmax, i = def->fast_outs(dmax); i < dmax; i++) {
  1896         Node* use = def->fast_out(i);
  1897         if (use->Opcode() == opc &&
  1898             use->req() == req()) {
  1899           uint j;
  1900           for (j = 0; j < use->req(); j++) {
  1901             if (use->in(j) != in(j)) {
  1902               break;
  1905           if (j == use->req()) {
  1906             return use;
  1912   return NULL;
  1916 //--------------------------unique_ctrl_out------------------------------
  1917 // Return the unique control out if only one. Null if none or more than one.
  1918 Node* Node::unique_ctrl_out() {
  1919   Node* found = NULL;
  1920   for (uint i = 0; i < outcnt(); i++) {
  1921     Node* use = raw_out(i);
  1922     if (use->is_CFG() && use != this) {
  1923       if (found != NULL) return NULL;
  1924       found = use;
  1927   return found;
  1930 //=============================================================================
  1931 //------------------------------yank-------------------------------------------
  1932 // Find and remove
  1933 void Node_List::yank( Node *n ) {
  1934   uint i;
  1935   for( i = 0; i < _cnt; i++ )
  1936     if( _nodes[i] == n )
  1937       break;
  1939   if( i < _cnt )
  1940     _nodes[i] = _nodes[--_cnt];
  1943 //------------------------------dump-------------------------------------------
  1944 void Node_List::dump() const {
  1945 #ifndef PRODUCT
  1946   for( uint i = 0; i < _cnt; i++ )
  1947     if( _nodes[i] ) {
  1948       tty->print("%5d--> ",i);
  1949       _nodes[i]->dump();
  1951 #endif
  1954 //=============================================================================
  1955 //------------------------------remove-----------------------------------------
  1956 void Unique_Node_List::remove( Node *n ) {
  1957   if( _in_worklist[n->_idx] ) {
  1958     for( uint i = 0; i < size(); i++ )
  1959       if( _nodes[i] == n ) {
  1960         map(i,Node_List::pop());
  1961         _in_worklist >>= n->_idx;
  1962         return;
  1964     ShouldNotReachHere();
  1968 //-----------------------remove_useless_nodes----------------------------------
  1969 // Remove useless nodes from worklist
  1970 void Unique_Node_List::remove_useless_nodes(VectorSet &useful) {
  1972   for( uint i = 0; i < size(); ++i ) {
  1973     Node *n = at(i);
  1974     assert( n != NULL, "Did not expect null entries in worklist");
  1975     if( ! useful.test(n->_idx) ) {
  1976       _in_worklist >>= n->_idx;
  1977       map(i,Node_List::pop());
  1978       // Node *replacement = Node_List::pop();
  1979       // if( i != size() ) { // Check if removing last entry
  1980       //   _nodes[i] = replacement;
  1981       // }
  1982       --i;  // Visit popped node
  1983       // If it was last entry, loop terminates since size() was also reduced
  1988 //=============================================================================
  1989 void Node_Stack::grow() {
  1990   size_t old_top = pointer_delta(_inode_top,_inodes,sizeof(INode)); // save _top
  1991   size_t old_max = pointer_delta(_inode_max,_inodes,sizeof(INode));
  1992   size_t max = old_max << 1;             // max * 2
  1993   _inodes = REALLOC_ARENA_ARRAY(_a, INode, _inodes, old_max, max);
  1994   _inode_max = _inodes + max;
  1995   _inode_top = _inodes + old_top;        // restore _top
  1998 //=============================================================================
  1999 uint TypeNode::size_of() const { return sizeof(*this); }
  2000 #ifndef PRODUCT
  2001 void TypeNode::dump_spec(outputStream *st) const {
  2002   if( !Verbose && !WizardMode ) {
  2003     // standard dump does this in Verbose and WizardMode
  2004     st->print(" #"); _type->dump_on(st);
  2007 #endif
  2008 uint TypeNode::hash() const {
  2009   return Node::hash() + _type->hash();
  2011 uint TypeNode::cmp( const Node &n ) const
  2012 { return !Type::cmp( _type, ((TypeNode&)n)._type ); }
  2013 const Type *TypeNode::bottom_type() const { return _type; }
  2014 const Type *TypeNode::Value( PhaseTransform * ) const { return _type; }
  2016 //------------------------------ideal_reg--------------------------------------
  2017 uint TypeNode::ideal_reg() const {
  2018   return Matcher::base2reg[_type->base()];

mercurial