Example #1
0
//------------------------------call_catch_cleanup-----------------------------
// If we inserted any instructions between a Call and his CatchNode,
// clone the instructions on all paths below the Catch.
void Block::call_catch_cleanup(Block_Array &bbs) {

  // End of region to clone
  uint end = end_idx();
  if( !_nodes[end]->is_Catch() ) return;
  // Start of region to clone
  uint beg = end;
  while( _nodes[beg-1]->Opcode() != Op_MachProj || 
        !_nodes[beg-1]->in(0)->is_Call() ) {
    beg--;
    assert(beg > 0,"Catch cleanup walking beyond block boundry");
  }
  if( beg == end ) return;

  // Clone along all Catch output paths.  Clone area between the 'beg' and
  // 'end' indices.
  for( uint i = 0; i < _num_succs; i++ ) {
    Block *sb = _succs[i];
    // Clone the entire area; ignoring the edge fixup for now.
    for( uint j = end; j > beg; j-- ) {
      Node *clone = _nodes[j-1]->clone();
      sb->_nodes.insert( 1, clone );
      bbs.map(clone->_idx,sb);
    }
  }


  // Fixup edges.  Check the def-use info per cloned Node
  for(uint i2 = beg; i2 < end; i2++ ) {
    uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
    Node *n = _nodes[i2];        // Node that got cloned
    // Need DU safe iterator because of edge manipulation in calls.
    Node_List *out = new Node_List(Thread::current()->resource_area());
    for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
      out->push(n->fast_out(j1));
    }
    uint max = out->size();
    for (uint j = 0; j < max; j++) {// For all users
      Node *use = out->pop();
      Block *buse = bbs[use->_idx];
      if( use->is_Phi() ) {
        for( uint k = 1; k < use->req(); k++ )
          if( use->in(k) == n ) 
            catch_cleanup_one_use( use, bbs[buse->pred(k)->_idx], n, this, bbs, beg, n_clone_idx, k );
      } else {
        catch_cleanup_one_use( use, buse, n, this, bbs, beg, n_clone_idx, -1 );
      }
    } // End for all users

  } // End of for all Nodes in cloned area

  // Remove the now-dead cloned ops
  for(uint i3 = beg; i3 < end; i3++ ) {
    _nodes[beg]->disconnect_inputs(NULL);
    _nodes.remove(beg);
  }

  // If the successor blocks have a CreateEx node, move it back to the top
  for(uint i4 = 0; i4 < _num_succs; i4++ ) {
    Block *sb = _succs[i4];
    MachNode *cex = sb->_nodes[1+end-beg]->is_Mach();
    if( cex && cex->ideal_Opcode() == Op_CreateEx ) {
      sb->_nodes.remove(1+end-beg);
      sb->_nodes.insert(1,cex);
    }
  }
}
Example #2
0
//------------------------------schedule_local---------------------------------
// Topological sort within a block.  Someday become a real scheduler.
bool Block::schedule_local(Matcher &matcher, Block_Array &bbs,int *ready_cnt, VectorSet &next_call, GrowableArray<uint> &node_latency) {
  // Already "sorted" are the block start Node (as the first entry), and
  // the block-ending Node and any trailing control projections.  We leave
  // these alone.  PhiNodes and ParmNodes are made to follow the block start
  // Node.  Everything else gets topo-sorted.

#ifndef PRODUCT
    if (TraceOptoPipelining) {
      tty->print("# before schedule_local\n");
      for (uint i = 0;i < _nodes.size();i++) {
        tty->print("# ");
        _nodes[i]->fast_dump();
      }
      tty->print("\n");
    }
#endif

  // RootNode is already sorted
  if( _nodes.size() == 1 ) return true;

  // Move PhiNodes and ParmNodes from 1 to cnt up to the start
  uint node_cnt = end_idx();
  uint phi_cnt = 1;
  uint i;
  for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
    Node *n = _nodes[i];
    if( n->is_Phi() ||          // Found a PhiNode or ParmNode
        (n->is_Proj()  && n->in(0) == head()) ) {
      // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
      _nodes.map(i,_nodes[phi_cnt]);
      _nodes.map(phi_cnt++,n);  // swap Phi/Parm up front
    } else {                    // All others
      // Count block-local inputs to 'n'
      uint cnt = n->len();      // Input count
      uint local = 0;
      for( uint j=0; j<cnt; j++ ) {
        Node *m = n->in(j);
        if( m && bbs[m->_idx] == this && !m->is_top() )
          local++;              // One more block-local input
      }
      ready_cnt[n->_idx] = local; // Count em up

      // A few node types require changing a required edge to a precedence edge
      // before allocation.
      MachNode *m = n->is_Mach();
      if( UseConcMarkSweepGC ) {
        if( m && m->ideal_Opcode() == Op_StoreCM ) {
          // Note: Required edges with an index greater than oper_input_base
          // are not supported by the allocator.
          // Note2: Can only depend on unmatched edge being last,
          // can not depend on its absolute position.
          Node *oop_store = n->in(n->req() - 1);
          n->del_req(n->req() - 1);
          n->add_prec(oop_store);
          assert(bbs[oop_store->_idx]->_dom_depth <= this->_dom_depth, "oop_store must dominate card-mark");
        }
      }
      if( m && m->ideal_Opcode() == Op_MemBarAcquire ) {
        Node *x = n->in(TypeFunc::Parms);
        n->del_req(TypeFunc::Parms);
        n->add_prec(x);
      }
    }
  }
  for(uint i2=i; i2<_nodes.size(); i2++ ) // Trailing guys get zapped count
    ready_cnt[_nodes[i2]->_idx] = 0;

  // All the prescheduled guys do not hold back internal nodes
  uint i3;
  for(i3 = 0; i3<phi_cnt; i3++ ) {  // For all pre-scheduled
    Node *n = _nodes[i3];       // Get pre-scheduled
    for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
      Node* m = n->fast_out(j);
      if( bbs[m->_idx] ==this ) // Local-block user
        ready_cnt[m->_idx]--;   // Fix ready count
    }
  }

  // Make a worklist
  Node_List worklist;
  for(uint i4=i3; i4<node_cnt; i4++ ) {    // Put ready guys on worklist
    Node *m = _nodes[i4];    
    if( !ready_cnt[m->_idx] )   // Zero ready count?
      worklist.push(m);         // Then on to worklist!
  }

  // Warm up the 'next_call' heuristic bits
  needed_for_next_call(_nodes[0], next_call, bbs);

#ifndef PRODUCT
    if (TraceOptoPipelining) {
      for (uint j=0; j<_nodes.size(); j++) {
        Node     *n = _nodes[j];
        int     idx = n->_idx;
        tty->print("#   ready cnt:%3d  ", ready_cnt[idx]);
        tty->print("latency:%3d  ", node_latency.at_grow(idx));
        tty->print("%4d: %s\n", idx, n->Name());
      }
    }
#endif

  // Pull from worklist and schedule
  while( worklist.size() ) {    // Worklist is not ready

#ifndef PRODUCT
    uint before_size = worklist.size();

    if (TraceOptoPipelining && before_size > 1) {
      tty->print("#    before select:");
      for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
        Node *n = worklist[i];      // Get Node on worklist
        tty->print(" %3d", n->_idx);
      }
      tty->print("\n");
    }
#endif

    // Select and pop a ready guy from worklist
    Node* n = select(worklist, bbs, ready_cnt, next_call, phi_cnt, node_latency);
    _nodes.map(phi_cnt++,n);    // Schedule him next
    MachNode *m = n->is_Mach();

#ifndef PRODUCT
    if (TraceOptoPipelining && before_size > 1) {
      tty->print("#  select %d: %s", n->_idx, n->Name());
      tty->print(", latency:%d", node_latency.at_grow(n->_idx));
      n->dump();
      tty->print("#    after select:");
      for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
        Node *n = worklist[i];      // Get Node on worklist
        tty->print(" %4d", n->_idx);
      }
      tty->print("\n");
    }

#endif
    if( m ) {
      MachCallNode *mcall = m->is_MachCall();
      if( mcall ) {
        phi_cnt = sched_call(matcher, bbs, phi_cnt, worklist, ready_cnt, mcall, next_call);
        continue;
      }
    }
    // Children are now all ready
    for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
      Node* m = n->fast_out(i5); // Get user
      if( bbs[m->_idx] != this ) continue;
      if( m->is_Phi() ) continue;
      if( !--ready_cnt[m->_idx] ) 
        worklist.push(m);
    }
  }

  if( phi_cnt != end_idx() ) {
    // did not schedule all.  Retry, Bailout, or Die
    Compile* C = matcher.C;
    if (C->subsume_loads() == true) {
      // Retry with subsume_loads == false
      C->set_result(Compile::Comp_subsumed_load_conflict);
    } else {
      // Bailout without retry
      C->set_result(Compile::Comp_no_retry);
    }
    // assert( phi_cnt == end_idx(), "did not schedule all" );
    return false;
  }

#ifndef PRODUCT
  if (TraceOptoPipelining) {
    tty->print("# after schedule_local\n");
    for (uint i = 0;i < _nodes.size();i++) {
      tty->print("# ");
      _nodes[i]->fast_dump();
    }
    tty->print("\n");
  }
#endif


  return true;
}
Example #3
0
//------------------------------implicit_null_check----------------------------
// Detect implicit-null-check opportunities.  Basically, find NULL checks 
// with suitable memory ops nearby.  Use the memory op to do the NULL check.
// I can generate a memory op if there is not one nearby.
void Block::implicit_null_check(Block_Array &bbs, GrowableArray<uint> &latency, Node *proj, Node *val) {
  // Assume if null check need for 0 offset then always needed
  // Intel solaris doesn't support any null checks yet and no
  // mechanism exists (yet) to set the switches at an os_cpu level
  if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;

  // Make sure the ptr-is-null path appears to be uncommon!
  float f = end()->is_Mach()->is_MachIf()->_prob;
  if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
  if( f > 0.0001 ) return;

  uint bidx = 0;                // Capture index of value into memop
  bool was_store;               // Memory op is a store op

  // Search the successor block for a load or store who's base value is also
  // the tested value.  There may be several.
  Node_List *out = new Node_List(Thread::current()->resource_area());
  MachNode *best = NULL;        // Best found so far
  for (DUIterator i = val->outs(); val->has_out(i); i++) {
    MachNode *mach = val->out(i)->is_Mach();
    if( !mach ) continue;
    was_store = false;
    switch( mach->ideal_Opcode() ) {
    case Op_LoadB:
    case Op_LoadC:
    case Op_LoadD:
    case Op_LoadF:
    case Op_LoadI:
    case Op_LoadL:
    case Op_LoadP:
    case Op_LoadS:
    case Op_LoadKlass:
    case Op_LoadRange:
    case Op_LoadD_unaligned:
    case Op_LoadL_unaligned:
      break;
    case Op_StoreB:
    case Op_StoreC:
    case Op_StoreCM:
    case Op_StoreD:
    case Op_StoreF:
    case Op_StoreI:
    case Op_StoreL:
    case Op_StoreP:
      was_store = true;         // Memory op is a store op
      // Stores will have their address in slot 2 (memory in slot 1).
      // If the value being nul-checked is in another slot, it means we
      // are storing the checked value, which does NOT check the value!
      if( mach->in(2) != val ) continue;
      break;                    // Found a memory op?
    case Op_StrComp:		
      // Not a legit memory op for implicit null check regardless of 
      // embedded loads
      continue;
    default:                    // Also check for embedded loads
      if( !mach->check_for_anti_dependence() )
        continue;               // Not an memory op; skip it
      break;
    }
    // check if the offset is not too high for implicit exception
    {
      intptr_t offset = 0;
      const TypePtr *adr_type = NULL;  // Do not need this return value here
      const Node* base = mach->get_base_and_disp(offset, adr_type);
      if (base == NULL || base == (Node*)-1) {
        // cannot reason about it; is probably not implicit null exception
      } else {
        const TypePtr* tptr = base->bottom_type()->is_ptr();
        // Give up if offset is not a compile-time constant
        if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
          continue;
        offset += tptr->_offset; // correct if base is offseted
	if( MacroAssembler::needs_explicit_null_check(offset) ) 
          continue;             // Give up is reference is beyond 4K page size
      }
    }

    // Check ctrl input to see if the null-check dominates the memory op
    Block *cb = bbs[mach->_idx];
    cb = cb->_idom;		// Always hoist at least 1 block
    if( !was_store ) {		// Stores can be hoisted only one block
      while( cb->_dom_depth > _dom_depth )
        cb = cb->_idom;		// Hoist loads as far as we want
    }
    if( cb != this ) continue;

    // Found a memory user; see if it can be hoisted to check-block
    uint vidx = 0;              // Capture index of value into memop
    uint j;
    for( j = mach->req()-1; j > 0; j-- ) {
      if( mach->in(j) == val ) vidx = j;
      // Block of memory-op input
      Block *inb = bbs[mach->in(j)->_idx];
      Block *b = this;          // Start from nul check
      while( b != inb && b->_dom_depth > inb->_dom_depth )
        b = b->_idom;           // search upwards for input
      // See if input dominates null check
      if( b != inb )
        break;
    }
    if( j > 0 ) 
      continue;
    Block *mb = bbs[mach->_idx]; 
    // Hoisting stores requires more checks for the anti-dependence case.
    // Give up hoisting if we have to move the store past any load.
    if( was_store ) {
      Block *b = mb;            // Start searching here for a local load
      // mach use (faulting) trying to hoist
      // n might be blocker to hoisting
      while( b != this ) {
        uint k;
        for( k = 1; k < b->_nodes.size(); k++ ) {
          Node *n = b->_nodes[k];
          if( n->check_for_anti_dependence() && 
              n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
	    break;              // Found anti-dependent load
        }
        if( k < b->_nodes.size() )
          break;                // Found anti-dependent load
        // Make sure control does not do a merge (would have to check allpaths)
        if( b->num_preds() != 2 ) break;
        b = bbs[b->pred(1)->_idx]; // Move up to predecessor block
      }
      if( b != this ) continue;
    }

    // Make sure this memory op is not already being used for a NullCheck
    MachNode *e = mb->end()->is_Mach();
    if( e && e->is_MachNullCheck() && e->in(1) == mach )
      continue;                 // Already being used as a NULL check

    // Found a candidate!  Pick one with least dom depth - the highest 
    // in the dom tree should be closest to the null check.
    if( !best || 
        bbs[mach->_idx]->_dom_depth < bbs[best->_idx]->_dom_depth ) {
      best = mach;
      bidx = vidx;

    }
  }
  // No candidate!
  if( !best ) return;

  // ---- Found an implicit null check
  extern int implicit_null_checks;
  implicit_null_checks++;

  // Hoist the memory candidate up to the end of the test block.
  Block *old_block = bbs[best->_idx];
  old_block->find_remove(best);
  add_inst(best);
  bbs.map(best->_idx,this);

  // Move the control dependence
  if (best->in(0) && best->in(0) == old_block->_nodes[0])
    best->set_req(0, _nodes[0]);

  // Check for flag-killing projections that also need to be hoisted
  // Should be DU safe because no edge updates.
  for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
    Node* n = best->fast_out(j);
    if( n->Opcode() == Op_MachProj ) {
      bbs[n->_idx]->find_remove(n);
      add_inst(n);
      bbs.map(n->_idx,this);
    }
  }

  // proj==Op_True --> ne test; proj==Op_False --> eq test.
  // One of two graph shapes got matched:
  //   (IfTrue  (If (Bool NE (CmpP ptr NULL))))
  //   (IfFalse (If (Bool EQ (CmpP ptr NULL))))
  // NULL checks are always branch-if-eq.  If we see a IfTrue projection
  // then we are replacing a 'ne' test with a 'eq' NULL check test.
  // We need to flip the projections to keep the same semantics.
  if( proj->Opcode() == Op_IfTrue ) {
    // Swap order of projections in basic block to swap branch targets
    Node *tmp1 = _nodes[end_idx()+1];
    Node *tmp2 = _nodes[end_idx()+2];
    _nodes.map(end_idx()+1, tmp2);
    _nodes.map(end_idx()+2, tmp1);    
    Node *tmp = new (1) Node(1);
    tmp1->replace_by(tmp);
    tmp2->replace_by(tmp1);
    tmp->replace_by(tmp2);
  }

  // Remove the existing null check; use a new implicit null check instead.
  // Since schedule-local needs precise def-use info, we need to correct
  // it as well.
  Node *old_tst = proj->in(0);
  MachNode *nul_chk = new MachNullCheckNode(old_tst->in(0),best,bidx);
  _nodes.map(end_idx(),nul_chk);
  bbs.map(nul_chk->_idx,this);
  // Redirect users of old_test to nul_chk
  for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
    old_tst->last_out(i2)->set_req(0, nul_chk);
  // Clean-up any dead code
  for (uint i3 = 0; i3 < old_tst->req(); i3++)
    old_tst->set_req(i3, NULL);
  latency.at_put_grow(nul_chk->_idx, nul_chk->latency_from_uses(bbs, latency));
  latency.at_put_grow(best   ->_idx, best   ->latency_from_uses(bbs, latency));

#ifndef PRODUCT
  if (TraceOptoPipelining) {
    tty->print("# implicit_null_check: latency %4d for ", latency.at_grow(best->_idx));
    best->fast_dump();
    tty->print("# implicit_null_check: latency %4d for ", latency.at_grow(nul_chk->_idx));
    nul_chk->fast_dump();
  }
#endif
}
Example #4
0
//------------------------------schedule_local---------------------------------
// Topological sort within a block.  Someday become a real scheduler.
bool Block::schedule_local(PhaseCFG *cfg, Matcher &matcher, GrowableArray<int> &ready_cnt, VectorSet &next_call) {
  // Already "sorted" are the block start Node (as the first entry), and
  // the block-ending Node and any trailing control projections.  We leave
  // these alone.  PhiNodes and ParmNodes are made to follow the block start
  // Node.  Everything else gets topo-sorted.

#ifndef PRODUCT
    if (cfg->trace_opto_pipelining()) {
      tty->print_cr("# --- schedule_local B%d, before: ---", _pre_order);
      for (uint i = 0;i < _nodes.size();i++) {
        tty->print("# ");
        _nodes[i]->fast_dump();
      }
      tty->print_cr("#");
    }
#endif

  // RootNode is already sorted
  if( _nodes.size() == 1 ) return true;

  // Move PhiNodes and ParmNodes from 1 to cnt up to the start
  uint node_cnt = end_idx();
  uint phi_cnt = 1;
  uint i;
  for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
    Node *n = _nodes[i];
    if( n->is_Phi() ||          // Found a PhiNode or ParmNode
        (n->is_Proj()  && n->in(0) == head()) ) {
      // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
      _nodes.map(i,_nodes[phi_cnt]);
      _nodes.map(phi_cnt++,n);  // swap Phi/Parm up front
    } else {                    // All others
      // Count block-local inputs to 'n'
      uint cnt = n->len();      // Input count
      uint local = 0;
      for( uint j=0; j<cnt; j++ ) {
        Node *m = n->in(j);
        if( m && cfg->_bbs[m->_idx] == this && !m->is_top() )
          local++;              // One more block-local input
      }
      ready_cnt.at_put(n->_idx, local); // Count em up

#ifdef ASSERT
      if( UseConcMarkSweepGC || UseG1GC ) {
        if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
          // Check the precedence edges
          for (uint prec = n->req(); prec < n->len(); prec++) {
            Node* oop_store = n->in(prec);
            if (oop_store != NULL) {
              assert(cfg->_bbs[oop_store->_idx]->_dom_depth <= this->_dom_depth, "oop_store must dominate card-mark");
            }
          }
        }
      }
#endif

      // A few node types require changing a required edge to a precedence edge
      // before allocation.
      if( n->is_Mach() && n->req() > TypeFunc::Parms &&
          (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
           n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
        // MemBarAcquire could be created without Precedent edge.
        // del_req() replaces the specified edge with the last input edge
        // and then removes the last edge. If the specified edge > number of
        // edges the last edge will be moved outside of the input edges array
        // and the edge will be lost. This is why this code should be
        // executed only when Precedent (== TypeFunc::Parms) edge is present.
        Node *x = n->in(TypeFunc::Parms);
        n->del_req(TypeFunc::Parms);
        n->add_prec(x);
      }
    }
  }
  for(uint i2=i; i2<_nodes.size(); i2++ ) // Trailing guys get zapped count
    ready_cnt.at_put(_nodes[i2]->_idx, 0);

  // All the prescheduled guys do not hold back internal nodes
  uint i3;
  for(i3 = 0; i3<phi_cnt; i3++ ) {  // For all pre-scheduled
    Node *n = _nodes[i3];       // Get pre-scheduled
    for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
      Node* m = n->fast_out(j);
      if( cfg->_bbs[m->_idx] ==this ) { // Local-block user
        int m_cnt = ready_cnt.at(m->_idx)-1;
        ready_cnt.at_put(m->_idx, m_cnt);   // Fix ready count
      }
    }
  }

  Node_List delay;
  // Make a worklist
  Node_List worklist;
  for(uint i4=i3; i4<node_cnt; i4++ ) {    // Put ready guys on worklist
    Node *m = _nodes[i4];
    if( !ready_cnt.at(m->_idx) ) {   // Zero ready count?
      if (m->is_iteratively_computed()) {
        // Push induction variable increments last to allow other uses
        // of the phi to be scheduled first. The select() method breaks
        // ties in scheduling by worklist order.
        delay.push(m);
      } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
        // Force the CreateEx to the top of the list so it's processed
        // first and ends up at the start of the block.
        worklist.insert(0, m);
      } else {
        worklist.push(m);         // Then on to worklist!
      }
    }
  }
  while (delay.size()) {
    Node* d = delay.pop();
    worklist.push(d);
  }

  // Warm up the 'next_call' heuristic bits
  needed_for_next_call(_nodes[0], next_call, cfg->_bbs);

#ifndef PRODUCT
    if (cfg->trace_opto_pipelining()) {
      for (uint j=0; j<_nodes.size(); j++) {
        Node     *n = _nodes[j];
        int     idx = n->_idx;
        tty->print("#   ready cnt:%3d  ", ready_cnt.at(idx));
        tty->print("latency:%3d  ", cfg->_node_latency->at_grow(idx));
        tty->print("%4d: %s\n", idx, n->Name());
      }
    }
#endif

  uint max_idx = (uint)ready_cnt.length();
  // Pull from worklist and schedule
  while( worklist.size() ) {    // Worklist is not ready

#ifndef PRODUCT
    if (cfg->trace_opto_pipelining()) {
      tty->print("#   ready list:");
      for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
        Node *n = worklist[i];      // Get Node on worklist
        tty->print(" %d", n->_idx);
      }
      tty->cr();
    }
#endif

    // Select and pop a ready guy from worklist
    Node* n = select(cfg, worklist, ready_cnt, next_call, phi_cnt);
    _nodes.map(phi_cnt++,n);    // Schedule him next

#ifndef PRODUCT
    if (cfg->trace_opto_pipelining()) {
      tty->print("#    select %d: %s", n->_idx, n->Name());
      tty->print(", latency:%d", cfg->_node_latency->at_grow(n->_idx));
      n->dump();
      if (Verbose) {
        tty->print("#   ready list:");
        for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
          Node *n = worklist[i];      // Get Node on worklist
          tty->print(" %d", n->_idx);
        }
        tty->cr();
      }
    }

#endif
    if( n->is_MachCall() ) {
      MachCallNode *mcall = n->as_MachCall();
      phi_cnt = sched_call(matcher, cfg->_bbs, phi_cnt, worklist, ready_cnt, mcall, next_call);
      continue;
    }

    if (n->is_Mach() && n->as_Mach()->has_call()) {
      RegMask regs;
      regs.Insert(matcher.c_frame_pointer());
      regs.OR(n->out_RegMask());

      MachProjNode *proj = new (matcher.C, 1) MachProjNode( n, 1, RegMask::Empty, MachProjNode::fat_proj );
      cfg->_bbs.map(proj->_idx,this);
      _nodes.insert(phi_cnt++, proj);

      add_call_kills(proj, regs, matcher._c_reg_save_policy, false);
    }

    // Children are now all ready
    for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
      Node* m = n->fast_out(i5); // Get user
      if( cfg->_bbs[m->_idx] != this ) continue;
      if( m->is_Phi() ) continue;
      if (m->_idx >= max_idx) { // new node, skip it
        assert(m->is_MachProj() && n->is_Mach() && n->as_Mach()->has_call(), "unexpected node types");
        continue;
      }
      int m_cnt = ready_cnt.at(m->_idx)-1;
      ready_cnt.at_put(m->_idx, m_cnt);
      if( m_cnt == 0 )
        worklist.push(m);
    }
  }

  if( phi_cnt != end_idx() ) {
    // did not schedule all.  Retry, Bailout, or Die
    Compile* C = matcher.C;
    if (C->subsume_loads() == true && !C->failing()) {
      // Retry with subsume_loads == false
      // If this is the first failure, the sentinel string will "stick"
      // to the Compile object, and the C2Compiler will see it and retry.
      C->record_failure(C2Compiler::retry_no_subsuming_loads());
    }
    // assert( phi_cnt == end_idx(), "did not schedule all" );
    return false;
  }

#ifndef PRODUCT
  if (cfg->trace_opto_pipelining()) {
    tty->print_cr("#");
    tty->print_cr("# after schedule_local");
    for (uint i = 0;i < _nodes.size();i++) {
      tty->print("# ");
      _nodes[i]->fast_dump();
    }
    tty->cr();
  }
#endif


  return true;
}
Example #5
0
//------------------------------implicit_null_check----------------------------
// Detect implicit-null-check opportunities.  Basically, find NULL checks
// with suitable memory ops nearby.  Use the memory op to do the NULL check.
// I can generate a memory op if there is not one nearby.
// The proj is the control projection for the not-null case.
// The val is the pointer being checked for nullness or
// decodeHeapOop_not_null node if it did not fold into address.
void Block::implicit_null_check(PhaseCFG *cfg, Node *proj, Node *val, int allowed_reasons) {
  // Assume if null check need for 0 offset then always needed
  // Intel solaris doesn't support any null checks yet and no
  // mechanism exists (yet) to set the switches at an os_cpu level
  if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;

  // Make sure the ptr-is-null path appears to be uncommon!
  float f = end()->as_MachIf()->_prob;
  if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
  if( f > PROB_UNLIKELY_MAG(4) ) return;

  uint bidx = 0;                // Capture index of value into memop
  bool was_store;               // Memory op is a store op

  // Get the successor block for if the test ptr is non-null
  Block* not_null_block;  // this one goes with the proj
  Block* null_block;
  if (_nodes[_nodes.size()-1] == proj) {
    null_block     = _succs[0];
    not_null_block = _succs[1];
  } else {
    assert(_nodes[_nodes.size()-2] == proj, "proj is one or the other");
    not_null_block = _succs[0];
    null_block     = _succs[1];
  }
  while (null_block->is_Empty() == Block::empty_with_goto) {
    null_block     = null_block->_succs[0];
  }

  // Search the exception block for an uncommon trap.
  // (See Parse::do_if and Parse::do_ifnull for the reason
  // we need an uncommon trap.  Briefly, we need a way to
  // detect failure of this optimization, as in 6366351.)
  {
    bool found_trap = false;
    for (uint i1 = 0; i1 < null_block->_nodes.size(); i1++) {
      Node* nn = null_block->_nodes[i1];
      if (nn->is_MachCall() &&
          nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) {
        const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
        if (trtype->isa_int() && trtype->is_int()->is_con()) {
          jint tr_con = trtype->is_int()->get_con();
          Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
          Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
          assert((int)reason < (int)BitsPerInt, "recode bit map");
          if (is_set_nth_bit(allowed_reasons, (int) reason)
              && action != Deoptimization::Action_none) {
            // This uncommon trap is sure to recompile, eventually.
            // When that happens, C->too_many_traps will prevent
            // this transformation from happening again.
            found_trap = true;
          }
        }
        break;
      }
    }
    if (!found_trap) {
      // We did not find an uncommon trap.
      return;
    }
  }

  // Check for decodeHeapOop_not_null node which did not fold into address
  bool is_decoden = ((intptr_t)val) & 1;
  val = (Node*)(((intptr_t)val) & ~1);

  assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() &&
         (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity");

  // Search the successor block for a load or store who's base value is also
  // the tested value.  There may be several.
  Node_List *out = new Node_List(Thread::current()->resource_area());
  MachNode *best = NULL;        // Best found so far
  for (DUIterator i = val->outs(); val->has_out(i); i++) {
    Node *m = val->out(i);
    if( !m->is_Mach() ) continue;
    MachNode *mach = m->as_Mach();
    was_store = false;
    int iop = mach->ideal_Opcode();
    switch( iop ) {
    case Op_LoadB:
    case Op_LoadUS:
    case Op_LoadD:
    case Op_LoadF:
    case Op_LoadI:
    case Op_LoadL:
    case Op_LoadP:
    case Op_LoadN:
    case Op_LoadS:
    case Op_LoadKlass:
    case Op_LoadNKlass:
    case Op_LoadRange:
    case Op_LoadD_unaligned:
    case Op_LoadL_unaligned:
      assert(mach->in(2) == val, "should be address");
      break;
    case Op_StoreB:
    case Op_StoreC:
    case Op_StoreCM:
    case Op_StoreD:
    case Op_StoreF:
    case Op_StoreI:
    case Op_StoreL:
    case Op_StoreP:
    case Op_StoreN:
      was_store = true;         // Memory op is a store op
      // Stores will have their address in slot 2 (memory in slot 1).
      // If the value being nul-checked is in another slot, it means we
      // are storing the checked value, which does NOT check the value!
      if( mach->in(2) != val ) continue;
      break;                    // Found a memory op?
    case Op_StrComp:
    case Op_StrEquals:
    case Op_StrIndexOf:
    case Op_AryEq:
      // Not a legit memory op for implicit null check regardless of
      // embedded loads
      continue;
    default:                    // Also check for embedded loads
      if( !mach->needs_anti_dependence_check() )
        continue;               // Not an memory op; skip it
      if( must_clone[iop] ) {
        // Do not move nodes which produce flags because
        // RA will try to clone it to place near branch and
        // it will cause recompilation, see clone_node().
        continue;
      }
      {
        // Check that value is used in memory address in
        // instructions with embedded load (CmpP val1,(val2+off)).
        Node* base;
        Node* index;
        const MachOper* oper = mach->memory_inputs(base, index);
        if (oper == NULL || oper == (MachOper*)-1) {
          continue;             // Not an memory op; skip it
        }
        if (val == base ||
            val == index && val->bottom_type()->isa_narrowoop()) {
          break;                // Found it
        } else {
          continue;             // Skip it
        }
      }
      break;
    }
    // check if the offset is not too high for implicit exception
    {
      intptr_t offset = 0;
      const TypePtr *adr_type = NULL;  // Do not need this return value here
      const Node* base = mach->get_base_and_disp(offset, adr_type);
      if (base == NULL || base == NodeSentinel) {
        // Narrow oop address doesn't have base, only index
        if( val->bottom_type()->isa_narrowoop() &&
            MacroAssembler::needs_explicit_null_check(offset) )
          continue;             // Give up if offset is beyond page size
        // cannot reason about it; is probably not implicit null exception
      } else {
        const TypePtr* tptr;
        if (UseCompressedOops && Universe::narrow_oop_shift() == 0) {
          // 32-bits narrow oop can be the base of address expressions
          tptr = base->bottom_type()->make_ptr();
        } else {
          // only regular oops are expected here
          tptr = base->bottom_type()->is_ptr();
        }
        // Give up if offset is not a compile-time constant
        if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
          continue;
        offset += tptr->_offset; // correct if base is offseted
        if( MacroAssembler::needs_explicit_null_check(offset) )
          continue;             // Give up is reference is beyond 4K page size
      }
    }

    // Check ctrl input to see if the null-check dominates the memory op
    Block *cb = cfg->_bbs[mach->_idx];
    cb = cb->_idom;             // Always hoist at least 1 block
    if( !was_store ) {          // Stores can be hoisted only one block
      while( cb->_dom_depth > (_dom_depth + 1))
        cb = cb->_idom;         // Hoist loads as far as we want
      // The non-null-block should dominate the memory op, too. Live
      // range spilling will insert a spill in the non-null-block if it is
      // needs to spill the memory op for an implicit null check.
      if (cb->_dom_depth == (_dom_depth + 1)) {
        if (cb != not_null_block) continue;
        cb = cb->_idom;
      }
    }
    if( cb != this ) continue;

    // Found a memory user; see if it can be hoisted to check-block
    uint vidx = 0;              // Capture index of value into memop
    uint j;
    for( j = mach->req()-1; j > 0; j-- ) {
      if( mach->in(j) == val ) {
        vidx = j;
        // Ignore DecodeN val which could be hoisted to where needed.
        if( is_decoden ) continue;
      }
      // Block of memory-op input
      Block *inb = cfg->_bbs[mach->in(j)->_idx];
      Block *b = this;          // Start from nul check
      while( b != inb && b->_dom_depth > inb->_dom_depth )
        b = b->_idom;           // search upwards for input
      // See if input dominates null check
      if( b != inb )
        break;
    }
    if( j > 0 )
      continue;
    Block *mb = cfg->_bbs[mach->_idx];
    // Hoisting stores requires more checks for the anti-dependence case.
    // Give up hoisting if we have to move the store past any load.
    if( was_store ) {
      Block *b = mb;            // Start searching here for a local load
      // mach use (faulting) trying to hoist
      // n might be blocker to hoisting
      while( b != this ) {
        uint k;
        for( k = 1; k < b->_nodes.size(); k++ ) {
          Node *n = b->_nodes[k];
          if( n->needs_anti_dependence_check() &&
              n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
            break;              // Found anti-dependent load
        }
        if( k < b->_nodes.size() )
          break;                // Found anti-dependent load
        // Make sure control does not do a merge (would have to check allpaths)
        if( b->num_preds() != 2 ) break;
        b = cfg->_bbs[b->pred(1)->_idx]; // Move up to predecessor block
      }
      if( b != this ) continue;
    }

    // Make sure this memory op is not already being used for a NullCheck
    Node *e = mb->end();
    if( e->is_MachNullCheck() && e->in(1) == mach )
      continue;                 // Already being used as a NULL check

    // Found a candidate!  Pick one with least dom depth - the highest
    // in the dom tree should be closest to the null check.
    if( !best ||
        cfg->_bbs[mach->_idx]->_dom_depth < cfg->_bbs[best->_idx]->_dom_depth ) {
      best = mach;
      bidx = vidx;

    }
  }
  // No candidate!
  if( !best ) return;

  // ---- Found an implicit null check
  extern int implicit_null_checks;
  implicit_null_checks++;

  if( is_decoden ) {
    // Check if we need to hoist decodeHeapOop_not_null first.
    Block *valb = cfg->_bbs[val->_idx];
    if( this != valb && this->_dom_depth < valb->_dom_depth ) {
      // Hoist it up to the end of the test block.
      valb->find_remove(val);
      this->add_inst(val);
      cfg->_bbs.map(val->_idx,this);
      // DecodeN on x86 may kill flags. Check for flag-killing projections
      // that also need to be hoisted.
      for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
        Node* n = val->fast_out(j);
        if( n->is_MachProj() ) {
          cfg->_bbs[n->_idx]->find_remove(n);
          this->add_inst(n);
          cfg->_bbs.map(n->_idx,this);
        }
      }
    }
  }
  // Hoist the memory candidate up to the end of the test block.
  Block *old_block = cfg->_bbs[best->_idx];
  old_block->find_remove(best);
  add_inst(best);
  cfg->_bbs.map(best->_idx,this);

  // Move the control dependence
  if (best->in(0) && best->in(0) == old_block->_nodes[0])
    best->set_req(0, _nodes[0]);

  // Check for flag-killing projections that also need to be hoisted
  // Should be DU safe because no edge updates.
  for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
    Node* n = best->fast_out(j);
    if( n->is_MachProj() ) {
      cfg->_bbs[n->_idx]->find_remove(n);
      add_inst(n);
      cfg->_bbs.map(n->_idx,this);
    }
  }

  Compile *C = cfg->C;
  // proj==Op_True --> ne test; proj==Op_False --> eq test.
  // One of two graph shapes got matched:
  //   (IfTrue  (If (Bool NE (CmpP ptr NULL))))
  //   (IfFalse (If (Bool EQ (CmpP ptr NULL))))
  // NULL checks are always branch-if-eq.  If we see a IfTrue projection
  // then we are replacing a 'ne' test with a 'eq' NULL check test.
  // We need to flip the projections to keep the same semantics.
  if( proj->Opcode() == Op_IfTrue ) {
    // Swap order of projections in basic block to swap branch targets
    Node *tmp1 = _nodes[end_idx()+1];
    Node *tmp2 = _nodes[end_idx()+2];
    _nodes.map(end_idx()+1, tmp2);
    _nodes.map(end_idx()+2, tmp1);
    Node *tmp = new (C, 1) Node(C->top()); // Use not NULL input
    tmp1->replace_by(tmp);
    tmp2->replace_by(tmp1);
    tmp->replace_by(tmp2);
    tmp->destruct();
  }

  // Remove the existing null check; use a new implicit null check instead.
  // Since schedule-local needs precise def-use info, we need to correct
  // it as well.
  Node *old_tst = proj->in(0);
  MachNode *nul_chk = new (C) MachNullCheckNode(old_tst->in(0),best,bidx);
  _nodes.map(end_idx(),nul_chk);
  cfg->_bbs.map(nul_chk->_idx,this);
  // Redirect users of old_test to nul_chk
  for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
    old_tst->last_out(i2)->set_req(0, nul_chk);
  // Clean-up any dead code
  for (uint i3 = 0; i3 < old_tst->req(); i3++)
    old_tst->set_req(i3, NULL);

  cfg->latency_from_uses(nul_chk);
  cfg->latency_from_uses(best);
}
Example #6
0
//------------------------------call_catch_cleanup-----------------------------
// If we inserted any instructions between a Call and his CatchNode,
// clone the instructions on all paths below the Catch.
void Block::call_catch_cleanup(Block_Array &bbs) {

  // End of region to clone
  uint end = end_idx();
  if( !_nodes[end]->is_Catch() ) return;
  // Start of region to clone
  uint beg = end;
  while(!_nodes[beg-1]->is_MachProj() ||
        !_nodes[beg-1]->in(0)->is_MachCall() ) {
    beg--;
    assert(beg > 0,"Catch cleanup walking beyond block boundary");
  }
  // Range of inserted instructions is [beg, end)
  if( beg == end ) return;

  // Clone along all Catch output paths.  Clone area between the 'beg' and
  // 'end' indices.
  for( uint i = 0; i < _num_succs; i++ ) {
    Block *sb = _succs[i];
    // Clone the entire area; ignoring the edge fixup for now.
    for( uint j = end; j > beg; j-- ) {
      // It is safe here to clone a node with anti_dependence
      // since clones dominate on each path.
      Node *clone = _nodes[j-1]->clone();
      sb->_nodes.insert( 1, clone );
      bbs.map(clone->_idx,sb);
    }
  }


  // Fixup edges.  Check the def-use info per cloned Node
  for(uint i2 = beg; i2 < end; i2++ ) {
    uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
    Node *n = _nodes[i2];        // Node that got cloned
    // Need DU safe iterator because of edge manipulation in calls.
    Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
    for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
      out->push(n->fast_out(j1));
    }
    uint max = out->size();
    for (uint j = 0; j < max; j++) {// For all users
      Node *use = out->pop();
      Block *buse = bbs[use->_idx];
      if( use->is_Phi() ) {
        for( uint k = 1; k < use->req(); k++ )
          if( use->in(k) == n ) {
            Node *fixup = catch_cleanup_find_cloned_def(bbs[buse->pred(k)->_idx], n, this, bbs, n_clone_idx);
            use->set_req(k, fixup);
          }
      } else {
        if (this == buse) {
          catch_cleanup_intra_block(use, n, this, beg, n_clone_idx);
        } else {
          catch_cleanup_inter_block(use, buse, n, this, bbs, n_clone_idx);
        }
      }
    } // End for all users

  } // End of for all Nodes in cloned area

  // Remove the now-dead cloned ops
  for(uint i3 = beg; i3 < end; i3++ ) {
    _nodes[beg]->disconnect_inputs(NULL);
    _nodes.remove(beg);
  }

  // If the successor blocks have a CreateEx node, move it back to the top
  for(uint i4 = 0; i4 < _num_succs; i4++ ) {
    Block *sb = _succs[i4];
    uint new_cnt = end - beg;
    // Remove any newly created, but dead, nodes.
    for( uint j = new_cnt; j > 0; j-- ) {
      Node *n = sb->_nodes[j];
      if (n->outcnt() == 0 &&
          (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
        n->disconnect_inputs(NULL);
        sb->_nodes.remove(j);
        new_cnt--;
      }
    }
    // If any newly created nodes remain, move the CreateEx node to the top
    if (new_cnt > 0) {
      Node *cex = sb->_nodes[1+new_cnt];
      if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
        sb->_nodes.remove(1+new_cnt);
        sb->_nodes.insert(1,cex);
      }
    }
  }
}