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Java example source code file (regalloc.cpp)

This example Java source code file (regalloc.cpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

matcher, max, new_resource_array, node, noderegsoverflowsize, optoreg::name, optoreg\:\:stack0, optoregpair, phaseregalloc\:\:_total_framesize, phaseregalloc\:\:is_oop, phaseregalloc\:\:print_statistics, phaseregalloc\:\:reg2offset_unchecked, product, total

The regalloc.cpp Java example source code

/*
 * 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()),
          "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

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