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 /*

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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 #include "precompiled.hpp"

 #include "memory/allocation.inline.hpp"

 #include "opto/callnode.hpp"

 #include "opto/chaitin.hpp"

 #include "opto/live.hpp"

 #include "opto/machnode.hpp"

 //=============================================================================

 //------------------------------PhaseLive--------------------------------------

 // Compute live-in/live-out.  We use a totally incremental algorithm.  The LIVE

 // problem is monotonic.  The steady-state solution looks like this: pull a

 // block from the worklist.  It has a set of delta's - values which are newly

 // live-in from the block.  Push these to the live-out sets of all predecessor

 // blocks.  At each predecessor, the new live-out values are ANDed with what is

 // already live-out (extra stuff is added to the live-out sets).  Then the

 // remaining new live-out values are ANDed with what is locally defined.

 // Leftover bits become the new live-in for the predecessor block, and the pred

 // block is put on the worklist.

 //   The locally live-in stuff is computed once and added to predecessor

 // live-out sets.  This separate compilation is done in the outer loop below.

 PhaseLive::PhaseLive( const PhaseCFG &cfg, LRG_List &names, Arena *arena ) : Phase(LIVE), _cfg(cfg), _names(names), _arena(arena), _live(0) {

 }

 void PhaseLive::compute(uint maxlrg) {

   _maxlrg   = maxlrg;

   _worklist = new (_arena) Block_List();

   // Init the sparse live arrays.  This data is live on exit from here!

   // The _live info is the live-out info.

   _live = (IndexSet*)_arena->Amalloc(sizeof(IndexSet)*_cfg._num_blocks);

   uint i;

   for( i=0; i<_cfg._num_blocks; i++ ) {

     _live[i].initialize(_maxlrg);

   }

   // Init the sparse arrays for delta-sets.

   ResourceMark rm;              // Nuke temp storage on exit

   // Does the memory used by _defs and _deltas get reclaimed?  Does it matter?  TT

   // Array of values defined locally in blocks

   _defs = NEW_RESOURCE_ARRAY(IndexSet,_cfg._num_blocks);

   for( i=0; i<_cfg._num_blocks; i++ ) {

     _defs[i].initialize(_maxlrg);

   }

   // Array of delta-set pointers, indexed by block pre_order-1.

   _deltas = NEW_RESOURCE_ARRAY(IndexSet*,_cfg._num_blocks);

   memset( _deltas, 0, sizeof(IndexSet*)* _cfg._num_blocks);

   _free_IndexSet = NULL;

   // Blocks having done pass-1

   VectorSet first_pass(Thread::current()->resource_area());

   // Outer loop: must compute local live-in sets and push into predecessors.

   uint iters = _cfg._num_blocks;        // stat counters

   for( uint j=_cfg._num_blocks; j>0; j-- ) {

     Block *b = _cfg._blocks[j-1];

     // Compute the local live-in set.  Start with any new live-out bits.

     IndexSet *use = getset( b );

     IndexSet *def = &_defs[b->_pre_order-1];

     DEBUG_ONLY(IndexSet *def_outside = getfreeset();)

     uint i;

     for( i=b->_nodes.size(); i>1; i-- ) {

       Node *n = b->_nodes[i-1];

       if( n->is_Phi() ) break;

       uint r = _names[n->_idx];

       assert(!def_outside->member(r), "Use of external LRG overlaps the same LRG defined in this block");

       def->insert( r );

       use->remove( r );

       uint cnt = n->req();

       for( uint k=1; k<cnt; k++ ) {

         Node *nk = n->in(k);

         uint nkidx = nk->_idx;

         if( _cfg._bbs[nkidx] != b ) {

           uint u = _names[nkidx];

           use->insert( u );

           DEBUG_ONLY(def_outside->insert( u );)

         }

       }

     }

 #ifdef ASSERT

     def_outside->set_next(_free_IndexSet);

     _free_IndexSet = def_outside;     // Drop onto free list

 #endif

     // Remove anything defined by Phis and the block start instruction

     for( uint k=i; k>0; k-- ) {

       uint r = _names[b->_nodes[k-1]->_idx];

       def->insert( r );

       use->remove( r );

     }

     // Push these live-in things to predecessors

     for( uint l=1; l<b->num_preds(); l++ ) {

       Block *p = _cfg._bbs[b->pred(l)->_idx];

       add_liveout( p, use, first_pass );

       // PhiNode uses go in the live-out set of prior blocks.

       for( uint k=i; k>0; k-- )

         add_liveout( p, _names[b->_nodes[k-1]->in(l)->_idx], first_pass );

     }

     freeset( b );

     first_pass.set(b->_pre_order);

     // Inner loop: blocks that picked up new live-out values to be propagated

     while( _worklist->size() ) {

         // !!!!!

 // #ifdef ASSERT

       iters++;

 // #endif

       Block *b = _worklist->pop();

       IndexSet *delta = getset(b);

       assert( delta->count(), "missing delta set" );

       // Add new-live-in to predecessors live-out sets

       for( uint l=1; l<b->num_preds(); l++ )

         add_liveout( _cfg._bbs[b->pred(l)->_idx], delta, first_pass );

       freeset(b);

     } // End of while-worklist-not-empty

   } // End of for-all-blocks-outer-loop

   // We explicitly clear all of the IndexSets which we are about to release.

   // This allows us to recycle their internal memory into IndexSet's free list.

   for( i=0; i<_cfg._num_blocks; i++ ) {

     _defs[i].clear();

     if (_deltas[i]) {

       // Is this always true?

       _deltas[i]->clear();

     }

   }

   IndexSet *free = _free_IndexSet;

   while (free != NULL) {

     IndexSet *temp = free;

     free = free->next();

     temp->clear();

   }

 }

 //------------------------------stats------------------------------------------

 #ifndef PRODUCT

 void PhaseLive::stats(uint iters) const {

 }

 #endif

 //------------------------------getset-----------------------------------------

 // Get an IndexSet for a block.  Return existing one, if any.  Make a new

 // empty one if a prior one does not exist.

 IndexSet *PhaseLive::getset( Block *p ) {

   IndexSet *delta = _deltas[p->_pre_order-1];

   if( !delta )                  // Not on worklist?

     // Get a free set; flag as being on worklist

     delta = _deltas[p->_pre_order-1] = getfreeset();

   return delta;                 // Return set of new live-out items

 }

 //------------------------------getfreeset-------------------------------------

 // Pull from free list, or allocate.  Internal allocation on the returned set

 // is always from thread local storage.

 IndexSet *PhaseLive::getfreeset( ) {

   IndexSet *f = _free_IndexSet;

   if( !f ) {

     f = new IndexSet;

 //    f->set_arena(Thread::current()->resource_area());

     f->initialize(_maxlrg, Thread::current()->resource_area());

   } else {

     // Pull from free list

     _free_IndexSet = f->next();

   //f->_cnt = 0;                        // Reset to empty

 //    f->set_arena(Thread::current()->resource_area());

     f->initialize(_maxlrg, Thread::current()->resource_area());

   }

   return f;

 }

 //------------------------------freeset----------------------------------------

 // Free an IndexSet from a block.

 void PhaseLive::freeset( const Block *p ) {

   IndexSet *f = _deltas[p->_pre_order-1];

   f->set_next(_free_IndexSet);

   _free_IndexSet = f;           // Drop onto free list

   _deltas[p->_pre_order-1] = NULL;

 }

 //------------------------------add_liveout------------------------------------

 // Add a live-out value to a given blocks live-out set.  If it is new, then

 // also add it to the delta set and stick the block on the worklist.

 void PhaseLive::add_liveout( Block *p, uint r, VectorSet &first_pass ) {

   IndexSet *live = &_live[p->_pre_order-1];

   if( live->insert(r) ) {       // If actually inserted...

     // We extended the live-out set.  See if the value is generated locally.

     // If it is not, then we must extend the live-in set.

     if( !_defs[p->_pre_order-1].member( r ) ) {

       if( !_deltas[p->_pre_order-1] && // Not on worklist?

           first_pass.test(p->_pre_order) )

         _worklist->push(p);     // Actually go on worklist if already 1st pass

       getset(p)->insert(r);

     }

   }

 }

 //------------------------------add_liveout------------------------------------

 // Add a vector of live-out values to a given blocks live-out set.

 void PhaseLive::add_liveout( Block *p, IndexSet *lo, VectorSet &first_pass ) {

   IndexSet *live = &_live[p->_pre_order-1];

   IndexSet *defs = &_defs[p->_pre_order-1];

   IndexSet *on_worklist = _deltas[p->_pre_order-1];

   IndexSet *delta = on_worklist ? on_worklist : getfreeset();

   IndexSetIterator elements(lo);

   uint r;

   while ((r = elements.next()) != 0) {

     if( live->insert(r) &&      // If actually inserted...

         !defs->member( r ) )    // and not defined locally

       delta->insert(r);         // Then add to live-in set

   }

   if( delta->count() ) {                // If actually added things

     _deltas[p->_pre_order-1] = delta; // Flag as on worklist now

     if( !on_worklist &&         // Not on worklist?

         first_pass.test(p->_pre_order) )

       _worklist->push(p);       // Actually go on worklist if already 1st pass

   } else {                      // Nothing there; just free it

     delta->set_next(_free_IndexSet);

     _free_IndexSet = delta;     // Drop onto free list

   }

 }

 #ifndef PRODUCT

 //------------------------------dump-------------------------------------------

 // Dump the live-out set for a block

 void PhaseLive::dump( const Block *b ) const {

   tty->print("Block %d: ",b->_pre_order);

   tty->print("LiveOut: ");  _live[b->_pre_order-1].dump();

   uint cnt = b->_nodes.size();

   for( uint i=0; i<cnt; i++ ) {

     tty->print("L%d/", _names[b->_nodes[i]->_idx] );

     b->_nodes[i]->dump();

   }

   tty->print("\n");

 }

 //------------------------------verify_base_ptrs-------------------------------

 // Verify that base pointers and derived pointers are still sane.

 void PhaseChaitin::verify_base_ptrs( ResourceArea *a ) const {

 #ifdef ASSERT

   Unique_Node_List worklist(a);

   for( uint i = 0; i < _cfg._num_blocks; i++ ) {

     Block *b = _cfg._blocks[i];

     for( uint j = b->end_idx() + 1; j > 1; j-- ) {

       Node *n = b->_nodes[j-1];

       if( n->is_Phi() ) break;

       // Found a safepoint?

       if( n->is_MachSafePoint() ) {

         MachSafePointNode *sfpt = n->as_MachSafePoint();

         JVMState* jvms = sfpt->jvms();

         if (jvms != NULL) {

           // Now scan for a live derived pointer

           if (jvms->oopoff() < sfpt->req()) {

             // Check each derived/base pair

             for (uint idx = jvms->oopoff(); idx < sfpt->req(); idx++) {

               Node *check = sfpt->in(idx);

               bool is_derived = ((idx - jvms->oopoff()) & 1) == 0;

               // search upwards through spills and spill phis for AddP

               worklist.clear();

               worklist.push(check);

               uint k = 0;

               while( k < worklist.size() ) {

                 check = worklist.at(k);

                 assert(check,"Bad base or derived pointer");

                 // See PhaseChaitin::find_base_for_derived() for all cases.

                 int isc = check->is_Copy();

                 if( isc ) {

                   worklist.push(check->in(isc));

                 } else if( check->is_Phi() ) {

                   for (uint m = 1; m < check->req(); m++)

                     worklist.push(check->in(m));

                 } else if( check->is_Con() ) {

                   if (is_derived) {

                     // Derived is NULL+offset

                     assert(!is_derived || check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad derived pointer");

                   } else {

                     assert(check->bottom_type()->is_ptr()->_offset == 0,"Bad base pointer");

                     // Base either ConP(NULL) or loadConP

                     if (check->is_Mach()) {

                       assert(check->as_Mach()->ideal_Opcode() == Op_ConP,"Bad base pointer");

                     } else {

                       assert(check->Opcode() == Op_ConP &&

                              check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad base pointer");

                     }

                   }

                 } else if( check->bottom_type()->is_ptr()->_offset == 0 ) {

                   if(check->is_Proj() || check->is_Mach() &&

                      (check->as_Mach()->ideal_Opcode() == Op_CreateEx ||

                       check->as_Mach()->ideal_Opcode() == Op_ThreadLocal ||

                       check->as_Mach()->ideal_Opcode() == Op_CMoveP ||

                       check->as_Mach()->ideal_Opcode() == Op_CheckCastPP ||

 #ifdef _LP64

                       UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_CastPP ||

                       UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_DecodeN ||

                       UseCompressedKlassPointers && check->as_Mach()->ideal_Opcode() == Op_DecodeNKlass ||

 #endif

                       check->as_Mach()->ideal_Opcode() == Op_LoadP ||

                       check->as_Mach()->ideal_Opcode() == Op_LoadKlass)) {

                     // Valid nodes

                   } else {

                     check->dump();

                     assert(false,"Bad base or derived pointer");

                   }

                 } else {

                   assert(is_derived,"Bad base pointer");

                   assert(check->is_Mach() && check->as_Mach()->ideal_Opcode() == Op_AddP,"Bad derived pointer");

                 }

                 k++;

                 assert(k < 100000,"Derived pointer checking in infinite loop");

               } // End while

             }

           } // End of check for derived pointers

         } // End of Kcheck for debug info

       } // End of if found a safepoint

     } // End of forall instructions in block

   } // End of forall blocks

 #endif

 }

 //------------------------------verify-------------------------------------

 // Verify that graphs and base pointers are still sane.

 void PhaseChaitin::verify( ResourceArea *a, bool verify_ifg ) const {

 #ifdef ASSERT

   if( VerifyOpto || VerifyRegisterAllocator ) {

     _cfg.verify();

     verify_base_ptrs(a);

     if(verify_ifg)

       _ifg->verify(this);

   }

 #endif

 }

 #endif