/*

 * 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.

 *

 */

class Arena;

class Bundle;

class Block;

class Block_Array;

class Node;

class Node_Array;

class Node_List;

class PhaseCFG;

class PhaseChaitin;

class Pipeline_Use_Element;

class Pipeline_Use;

#ifndef PRODUCT

#define DEBUG_ARG(x) , x

#else

#define DEBUG_ARG(x)

#endif

// Define the initial sizes for allocation of the resizable code buffer

enum {

  initial_code_capacity  =  16 * 1024,

  initial_stub_capacity  =   4 * 1024,

  initial_const_capacity =   4 * 1024,

  initial_locs_capacity  =   3 * 1024

};

//------------------------------Scheduling----------------------------------

// This class contains all the information necessary to implement instruction

// scheduling and bundling.

class Scheduling {

private:

  // Arena to use

  Arena *_arena;

  // Control-Flow Graph info

  PhaseCFG *_cfg;

  // Register Allocation info

  PhaseRegAlloc *_regalloc;

  // Number of nodes in the method

  uint _node_bundling_limit;

  // List of scheduled nodes. Generated in reverse order

  Node_List _scheduled;

  // List of nodes currently available for choosing for scheduling

  Node_List _available;

  // Mapping from node (index) to basic block

  Block_Array& _bbs;

  // For each instruction beginning a bundle, the number of following

  // nodes to be bundled with it.

  Bundle *_node_bundling_base;

  // Mapping from register to Node

  Node_List _reg_node;

  // Free list for pinch nodes.

  Node_List _pinch_free_list;

  // Latency from the beginning of the containing basic block (base 1)

  // for each node.

  unsigned short *_node_latency;

  // Number of uses of this node within the containing basic block.

  short *_uses;

  // Schedulable portion of current block.  Skips Region/Phi/CreateEx up

  // front, branch+proj at end.  Also skips Catch/CProj (same as

  // branch-at-end), plus just-prior exception-throwing call.

  uint _bb_start, _bb_end;

  // Latency from the end of the basic block as scheduled

  unsigned short *_current_latency;

  // Remember the next node

  Node *_next_node;

  // Use this for an unconditional branch delay slot

  Node *_unconditional_delay_slot;

  // Pointer to a Nop

  MachNopNode *_nop;

  // Length of the current bundle, in instructions

  uint _bundle_instr_count;

  // Current Cycle number, for computing latencies and bundling

  uint _bundle_cycle_number;

  // Bundle information

  Pipeline_Use_Element _bundle_use_elements[resource_count];

  Pipeline_Use         _bundle_use;

  // Dump the available list

  void dump_available() const;

public:

  Scheduling(Arena *arena, Compile &compile);

  // Destructor

  NOT_PRODUCT( ~Scheduling(); )

  // Step ahead "i" cycles

  void step(uint i);

  // Step ahead 1 cycle, and clear the bundle state (for example,

  // at a branch target)

  void step_and_clear();

  Bundle* node_bundling(const Node *n) {

    assert(valid_bundle_info(n), "oob");

    return (&_node_bundling_base[n->_idx]);

  }

  bool valid_bundle_info(const Node *n) const {

    return (_node_bundling_limit > n->_idx);

  }

  bool starts_bundle(const Node *n) const {

    return (_node_bundling_limit > n->_idx && _node_bundling_base[n->_idx].starts_bundle());

  }

  // Do the scheduling

  void DoScheduling();

  // Compute the local latencies walking forward over the list of

  // nodes for a basic block

  void ComputeLocalLatenciesForward(const Block *bb);

  // Compute the register antidependencies within a basic block

  void ComputeRegisterAntidependencies(Block *bb);

  void verify_do_def( Node *n, OptoReg::Name def, const char *msg );

  void verify_good_schedule( Block *b, const char *msg );

  void anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def );

  void anti_do_use( Block *b, Node *use, OptoReg::Name use_reg );

  // Add a node to the current bundle

  void AddNodeToBundle(Node *n, const Block *bb);

  // Add a node to the list of available nodes

  void AddNodeToAvailableList(Node *n);

  // Compute the local use count for the nodes in a block, and compute

  // the list of instructions with no uses in the block as available

  void ComputeUseCount(const Block *bb);

  // Choose an instruction from the available list to add to the bundle

  Node * ChooseNodeToBundle();

  // See if this Node fits into the currently accumulating bundle

  bool NodeFitsInBundle(Node *n);

  // Decrement the use count for a node

 void DecrementUseCounts(Node *n, const Block *bb);

  // Garbage collect pinch nodes for reuse by other blocks.

  void garbage_collect_pinch_nodes();

  // Clean up a pinch node for reuse (helper for above).

  void cleanup_pinch( Node *pinch );

  // Information for statistics gathering

#ifndef PRODUCT

private:

  // Gather information on size of nops relative to total

  uint _branches, _unconditional_delays;

  static uint _total_nop_size, _total_method_size;

  static uint _total_branches, _total_unconditional_delays;

  static uint _total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];

public:

  static void print_statistics();

  static void increment_instructions_per_bundle(uint i) {

    _total_instructions_per_bundle[i]++;

  }

  static void increment_nop_size(uint s) {

    _total_nop_size += s;

  }

  static void increment_method_size(uint s) {

    _total_method_size += s;

  }

#endif

};