JDK14/Java14源码在线阅读

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.
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#ifndef SHARE_OPTO_REGALLOC_HPP
#define SHARE_OPTO_REGALLOC_HPP

#include "code/vmreg.hpp"
#include "opto/block.hpp"
#include "opto/matcher.hpp"
#include "opto/phase.hpp"

class Node;
class Matcher;
class PhaseCFG;

#define  MAX_REG_ALLOCATORS   10

//------------------------------PhaseRegAlloc------------------------------------
// Abstract register allocator
class PhaseRegAlloc : public Phase {
  friend class VMStructs;
  static void (*_alloc_statistics[MAX_REG_ALLOCATORS])();
  static int _num_allocators;

protected:
  OptoRegPair  *_node_regs;
  uint         _node_regs_max_index;
  VectorSet    _node_oops;         // Mapping from node indices to oopiness

  void alloc_node_regs(int size);  // allocate _node_regs table with at least "size" elements

  PhaseRegAlloc( uint unique, PhaseCFG &cfg, Matcher &matcher,
                 void (*pr_stats)());
public:
  PhaseCFG &_cfg;               // Control flow graph
  uint _framesize;              // Size of frame in stack-slots. not counting preserve area
  OptoReg::Name _max_reg;       // Past largest register seen
  Matcher &_matcher;            // Convert Ideal to MachNodes
  uint node_regs_max_index() const { return _node_regs_max_index; }

  // Get the register associated with the Node
  OptoReg::Name get_reg_first( const Node *n ) const {
    debug_only( if( n->_idx >= _node_regs_max_index ) n->dump(); );
    assert( n->_idx < _node_regs_max_index, "Exceeded _node_regs array");
    return _node_regs[n->_idx].first();
  }
  OptoReg::Name get_reg_second( const Node *n ) const {
    debug_only( if( n->_idx >= _node_regs_max_index ) n->dump(); );
    assert( n->_idx < _node_regs_max_index, "Exceeded _node_regs array");
    return _node_regs[n->_idx].second();
  }

  // Do all the real work of allocate
  virtual void Register_Allocate() = 0;


  // notify the register allocator that "node" is a new reference
  // to the value produced by "old_node"
  virtual void add_reference( const Node *node, const Node *old_node) = 0;


  // Set the register associated with a new Node
  void set_bad( uint idx ) {
    assert( idx < _node_regs_max_index, "Exceeded _node_regs array");
    _node_regs[idx].set_bad();
  }
  void set1( uint idx, OptoReg::Name reg ) {
    assert( idx < _node_regs_max_index, "Exceeded _node_regs array");
    _node_regs[idx].set1(reg);
  }
  void set2( uint idx, OptoReg::Name reg ) {
    assert( idx < _node_regs_max_index, "Exceeded _node_regs array");
    _node_regs[idx].set2(reg);
  }
  void set_pair( uint idx, OptoReg::Name hi, OptoReg::Name lo ) {
    assert( idx < _node_regs_max_index, "Exceeded _node_regs array");
    _node_regs[idx].set_pair(hi, lo);
  }
  void set_ptr( uint idx, OptoReg::Name reg ) {
    assert( idx < _node_regs_max_index, "Exceeded _node_regs array");
    _node_regs[idx].set_ptr(reg);
  }
  // Set and query if a node produces an oop
  void set_oop( const Node *n, bool );
  bool is_oop( const Node *n ) const;

  // Convert a register number to a stack offset
  int reg2offset          ( OptoReg::Name reg ) const;
  int reg2offset_unchecked( OptoReg::Name reg ) const;

  // Convert a stack offset to a register number
  OptoReg::Name offset2reg( int stk_offset ) const;

  // Get the register encoding associated with the Node
  int get_encode(const Node *n) const {
    assert( n->_idx < _node_regs_max_index, "Exceeded _node_regs array");

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