text: /*
   * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
   * 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
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   *
   */
  
  #include "precompiled.hpp"
  #include "opto/regalloc.hpp"
  
  static const int NodeRegsOverflowSize = 200;
  
  void (*PhaseRegAlloc::_alloc_statistics[MAX_REG_ALLOCATORS])();
  int PhaseRegAlloc::_num_allocators = 0;
  #ifndef PRODUCT
  int PhaseRegAlloc::_total_framesize = 0;
  int PhaseRegAlloc::_max_framesize = 0;
  #endif
  
  PhaseRegAlloc::PhaseRegAlloc( uint unique, PhaseCFG &cfg,
                                Matcher &matcher,
                                void (*pr_stats)() ):
                 Phase(Register_Allocation), _cfg(cfg), _matcher(matcher),
                 _node_oops(Thread::current()->resource_area()),
                 _node_regs(0),
                 _node_regs_max_index(0),
                 _framesize(0xdeadbeef)
  {
      int i;
  
      for (i=0; i < _num_allocators; i++) {
          if (_alloc_statistics[i] == pr_stats)
              return;
      }
      assert((_num_allocators + 1) < MAX_REG_ALLOCATORS, "too many register allocators");
      _alloc_statistics[_num_allocators++] = pr_stats;
  }
  
  
  //------------------------------reg2offset-------------------------------------
  int PhaseRegAlloc::reg2offset_unchecked( OptoReg::Name reg ) const {
    // Slots below _max_in_arg_stack_reg are offset by the entire frame.
    // Slots above _max_in_arg_stack_reg are frame_slots and are not offset.
    int slot = (reg < _matcher._new_SP)
      ? reg - OptoReg::stack0() + _framesize
      : reg - _matcher._new_SP;
    // Note:  We use the direct formula (reg - SharedInfo::stack0) instead of
    // OptoReg::reg2stack(reg), in order to avoid asserts in the latter
    // function.  This routine must remain unchecked, so that dump_frame()
    // can do its work undisturbed.
    // %%% not really clear why reg2stack would assert here
  
    return slot*VMRegImpl::stack_slot_size;
  }
  
  int PhaseRegAlloc::reg2offset( OptoReg::Name reg ) const {
  
    // Not allowed in the out-preserve area.
    // In-preserve area is allowed so Intel can fetch the return pc out.
    assert( reg <  _matcher._old_SP ||
            (reg >= OptoReg::add(_matcher._old_SP,C->out_preserve_stack_slots()) &&
             reg <  _matcher._in_arg_limit) ||
            reg >=  OptoReg::add(_matcher._new_SP, C->out_preserve_stack_slots()) ||
            // Allow return_addr in the out-preserve area.
            reg == _matcher.return_addr(),
            "register allocated in a preserve area" );
    return reg2offset_unchecked( reg );
  }
  
  //------------------------------offset2reg-------------------------------------
  OptoReg::Name PhaseRegAlloc::offset2reg(int stk_offset) const {
    int slot = stk_offset / jintSize;
    int reg = (slot < (int) _framesize)
      ? slot + _matcher._new_SP
      : OptoReg::stack2reg(slot) - _framesize;
    assert(stk_offset == reg2offset((OptoReg::Name) reg),
           "offset2reg does not invert properly");
    return (OptoReg::Name) reg;
  }
  
  //------------------------------set_oop----------------------------------------
  void PhaseRegAlloc::set_oop( const Node *n, bool is_an_oop ) {
    if( is_an_oop ) {
      _node_oops.set(n->_idx);
    }
  }
  
  //------------------------------is_oop-----------------------------------------
  bool PhaseRegAlloc::is_oop( const Node *n ) const {
    return _node_oops.test(n->_idx) != 0;
  }
  
  // Allocate _node_regs table with at least "size" elements
  void PhaseRegAlloc::alloc_node_regs(int size) {
    _node_regs_max_index = size + (size >> 1) + NodeRegsOverflowSize;
    _node_regs = NEW_RESOURCE_ARRAY( OptoRegPair, _node_regs_max_index );
    // We assume our caller will fill in all elements up to size-1, so
    // only the extra space we allocate is initialized here.
    for( uint i = size; i < _node_regs_max_index; ++i )
      _node_regs[i].set_bad();
  }
  
  #ifndef PRODUCT
  void
  PhaseRegAlloc::print_statistics() {
    tty->print_cr("Total frameslots = %d, Max frameslots = %d", _total_framesize, _max_framesize);
    int i;
  
    for (i=0; i < _num_allocators; i++) {
      _alloc_statistics[i]();
    }
  }
  #endif
  