--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/opto/chaitin.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,501 @@
+/*
+ * Copyright 1997-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+class LoopTree;
+class MachCallNode;
+class MachSafePointNode;
+class Matcher;
+class PhaseCFG;
+class PhaseLive;
+class PhaseRegAlloc;
+class   PhaseChaitin;
+
+#define OPTO_DEBUG_SPLIT_FREQ  BLOCK_FREQUENCY(0.001)
+#define OPTO_LRG_HIGH_FREQ     BLOCK_FREQUENCY(0.25)
+
+//------------------------------LRG--------------------------------------------
+// Live-RanGe structure.
+class LRG : public ResourceObj {
+public:
+  enum { SPILL_REG=29999 };     // Register number of a spilled LRG
+
+  double _cost;                 // 2 for loads/1 for stores times block freq
+  double _area;                 // Sum of all simultaneously live values
+  double score() const;         // Compute score from cost and area
+  double _maxfreq;              // Maximum frequency of any def or use
+
+  Node *_def;                   // Check for multi-def live ranges
+#ifndef PRODUCT
+  GrowableArray<Node*>* _defs;
+#endif
+
+  uint _risk_bias;              // Index of LRG which we want to avoid color
+  uint _copy_bias;              // Index of LRG which we want to share color
+
+  uint _next;                   // Index of next LRG in linked list
+  uint _prev;                   // Index of prev LRG in linked list
+private:
+  uint _reg;                    // Chosen register; undefined if mask is plural
+public:
+  // Return chosen register for this LRG.  Error if the LRG is not bound to
+  // a single register.
+  OptoReg::Name reg() const { return OptoReg::Name(_reg); }
+  void set_reg( OptoReg::Name r ) { _reg = r; }
+
+private:
+  uint _eff_degree;             // Effective degree: Sum of neighbors _num_regs
+public:
+  int degree() const { assert( _degree_valid, "" ); return _eff_degree; }
+  // Degree starts not valid and any change to the IFG neighbor
+  // set makes it not valid.
+  void set_degree( uint degree ) { _eff_degree = degree; debug_only(_degree_valid = 1;) }
+  // Made a change that hammered degree
+  void invalid_degree() { debug_only(_degree_valid=0;) }
+  // Incrementally modify degree.  If it was correct, it should remain correct
+  void inc_degree( uint mod ) { _eff_degree += mod; }
+  // Compute the degree between 2 live ranges
+  int compute_degree( LRG &l ) const;
+
+private:
+  RegMask _mask;                // Allowed registers for this LRG
+  uint _mask_size;              // cache of _mask.Size();
+public:
+  int compute_mask_size() const { return _mask.is_AllStack() ? 65535 : _mask.Size(); }
+  void set_mask_size( int size ) {
+    assert((size == 65535) || (size == (int)_mask.Size()), "");
+    _mask_size = size;
+    debug_only(_msize_valid=1;)
+    debug_only( if( _num_regs == 2 && !_fat_proj ) _mask.VerifyPairs(); )
+  }
+  void compute_set_mask_size() { set_mask_size(compute_mask_size()); }
+  int mask_size() const { assert( _msize_valid, "mask size not valid" );
+                          return _mask_size; }
+  // Get the last mask size computed, even if it does not match the
+  // count of bits in the current mask.
+  int get_invalid_mask_size() const { return _mask_size; }
+  const RegMask &mask() const { return _mask; }
+  void set_mask( const RegMask &rm ) { _mask = rm; debug_only(_msize_valid=0;)}
+  void AND( const RegMask &rm ) { _mask.AND(rm); debug_only(_msize_valid=0;)}
+  void SUBTRACT( const RegMask &rm ) { _mask.SUBTRACT(rm); debug_only(_msize_valid=0;)}
+  void Clear()   { _mask.Clear()  ; debug_only(_msize_valid=1); _mask_size = 0; }
+  void Set_All() { _mask.Set_All(); debug_only(_msize_valid=1); _mask_size = RegMask::CHUNK_SIZE; }
+  void Insert( OptoReg::Name reg ) { _mask.Insert(reg);  debug_only(_msize_valid=0;) }
+  void Remove( OptoReg::Name reg ) { _mask.Remove(reg);  debug_only(_msize_valid=0;) }
+  void ClearToPairs() { _mask.ClearToPairs(); debug_only(_msize_valid=0;) }
+
+  // Number of registers this live range uses when it colors
+private:
+  uint8 _num_regs;              // 2 for Longs and Doubles, 1 for all else
+                                // except _num_regs is kill count for fat_proj
+public:
+  int num_regs() const { return _num_regs; }
+  void set_num_regs( int reg ) { assert( _num_regs == reg || !_num_regs, "" ); _num_regs = reg; }
+
+private:
+  // Number of physical registers this live range uses when it colors
+  // Architecture and register-set dependent
+  uint8 _reg_pressure;
+public:
+  void set_reg_pressure(int i)  { _reg_pressure = i; }
+  int      reg_pressure() const { return _reg_pressure; }
+
+  // How much 'wiggle room' does this live range have?
+  // How many color choices can it make (scaled by _num_regs)?
+  int degrees_of_freedom() const { return mask_size() - _num_regs; }
+  // Bound LRGs have ZERO degrees of freedom.  We also count
+  // must_spill as bound.
+  bool is_bound  () const { return _is_bound; }
+  // Negative degrees-of-freedom; even with no neighbors this
+  // live range must spill.
+  bool not_free() const { return degrees_of_freedom() <  0; }
+  // Is this live range of "low-degree"?  Trivially colorable?
+  bool lo_degree () const { return degree() <= degrees_of_freedom(); }
+  // Is this live range just barely "low-degree"?  Trivially colorable?
+  bool just_lo_degree () const { return degree() == degrees_of_freedom(); }
+
+  uint   _is_oop:1,             // Live-range holds an oop
+         _is_float:1,           // True if in float registers
+         _was_spilled1:1,       // True if prior spilling on def
+         _was_spilled2:1,       // True if twice prior spilling on def
+         _is_bound:1,           // live range starts life with no
+                                // degrees of freedom.
+         _direct_conflict:1,    // True if def and use registers in conflict
+         _must_spill:1,         // live range has lost all degrees of freedom
+    // If _fat_proj is set, live range does NOT require aligned, adjacent
+    // registers and has NO interferences.
+    // If _fat_proj is clear, live range requires num_regs() to be a power of
+    // 2, and it requires registers to form an aligned, adjacent set.
+         _fat_proj:1,           //
+         _was_lo:1,             // Was lo-degree prior to coalesce
+         _msize_valid:1,        // _mask_size cache valid
+         _degree_valid:1,       // _degree cache valid
+         _has_copy:1,           // Adjacent to some copy instruction
+         _at_risk:1;            // Simplify says this guy is at risk to spill
+
+
+  // Alive if non-zero, dead if zero
+  bool alive() const { return _def != NULL; }
+
+#ifndef PRODUCT
+  void dump( ) const;
+#endif
+};
+
+//------------------------------LRG_List---------------------------------------
+// Map Node indices to Live RanGe indices.
+// Array lookup in the optimized case.
+class LRG_List : public ResourceObj {
+  uint _cnt, _max;
+  uint* _lidxs;
+  ReallocMark _nesting;         // assertion check for reallocations
+public:
+  LRG_List( uint max );
+
+  uint lookup( uint nidx ) const {
+    return _lidxs[nidx];
+  }
+  uint operator[] (uint nidx) const { return lookup(nidx); }
+
+  void map( uint nidx, uint lidx ) {
+    assert( nidx < _cnt, "oob" );
+    _lidxs[nidx] = lidx;
+  }
+  void extend( uint nidx, uint lidx );
+
+  uint Size() const { return _cnt; }
+};
+
+//------------------------------IFG--------------------------------------------
+//                         InterFerence Graph
+// An undirected graph implementation.  Created with a fixed number of
+// vertices.  Edges can be added & tested.  Vertices can be removed, then
+// added back later with all edges intact.  Can add edges between one vertex
+// and a list of other vertices.  Can union vertices (and their edges)
+// together.  The IFG needs to be really really fast, and also fairly
+// abstract!  It needs abstraction so I can fiddle with the implementation to
+// get even more speed.
+class PhaseIFG : public Phase {
+  // Current implementation: a triangular adjacency list.
+
+  // Array of adjacency-lists, indexed by live-range number
+  IndexSet *_adjs;
+
+  // Assertion bit for proper use of Squaring
+  bool _is_square;
+
+  // Live range structure goes here
+  LRG *_lrgs;                   // Array of LRG structures
+
+public:
+  // Largest live-range number
+  uint _maxlrg;
+
+  Arena *_arena;
+
+  // Keep track of inserted and deleted Nodes
+  VectorSet *_yanked;
+
+  PhaseIFG( Arena *arena );
+  void init( uint maxlrg );
+
+  // Add edge between a and b.  Returns true if actually addded.
+  int add_edge( uint a, uint b );
+
+  // Add edge between a and everything in the vector
+  void add_vector( uint a, IndexSet *vec );
+
+  // Test for edge existance
+  int test_edge( uint a, uint b ) const;
+
+  // Square-up matrix for faster Union
+  void SquareUp();
+
+  // Return number of LRG neighbors
+  uint neighbor_cnt( uint a ) const { return _adjs[a].count(); }
+  // Union edges of b into a on Squared-up matrix
+  void Union( uint a, uint b );
+  // Test for edge in Squared-up matrix
+  int test_edge_sq( uint a, uint b ) const;
+  // Yank a Node and all connected edges from the IFG.  Be prepared to
+  // re-insert the yanked Node in reverse order of yanking.  Return a
+  // list of neighbors (edges) yanked.
+  IndexSet *remove_node( uint a );
+  // Reinsert a yanked Node
+  void re_insert( uint a );
+  // Return set of neighbors
+  IndexSet *neighbors( uint a ) const { return &_adjs[a]; }
+
+#ifndef PRODUCT
+  // Dump the IFG
+  void dump() const;
+  void stats() const;
+  void verify( const PhaseChaitin * ) const;
+#endif
+
+  //--------------- Live Range Accessors
+  LRG &lrgs(uint idx) const { assert(idx < _maxlrg, "oob"); return _lrgs[idx]; }
+
+  // Compute and set effective degree.  Might be folded into SquareUp().
+  void Compute_Effective_Degree();
+
+  // Compute effective degree as the sum of neighbors' _sizes.
+  int effective_degree( uint lidx ) const;
+};
+
+// TEMPORARILY REPLACED WITH COMMAND LINE FLAG
+
+//// !!!!! Magic Constants need to move into ad file
+#ifdef SPARC
+//#define FLOAT_PRESSURE 30  /*     SFLT_REG_mask.Size() - 1 */
+//#define INT_PRESSURE   23  /* NOTEMP_I_REG_mask.Size() - 1 */
+#define FLOAT_INCREMENT(regs) regs
+#else
+//#define FLOAT_PRESSURE 6
+//#define INT_PRESSURE   6
+#define FLOAT_INCREMENT(regs) 1
+#endif
+
+//------------------------------Chaitin----------------------------------------
+// Briggs-Chaitin style allocation, mostly.
+class PhaseChaitin : public PhaseRegAlloc {
+
+  int _trip_cnt;
+  int _alternate;
+
+  uint _maxlrg;                 // Max live range number
+  LRG &lrgs(uint idx) const { return _ifg->lrgs(idx); }
+  PhaseLive *_live;             // Liveness, used in the interference graph
+  PhaseIFG *_ifg;               // Interference graph (for original chunk)
+  Node_List **_lrg_nodes;       // Array of node; lists for lrgs which spill
+  VectorSet _spilled_once;      // Nodes that have been spilled
+  VectorSet _spilled_twice;     // Nodes that have been spilled twice
+
+  LRG_List _names;              // Map from Nodes to Live RanGes
+
+  // Union-find map.  Declared as a short for speed.
+  // Indexed by live-range number, it returns the compacted live-range number
+  LRG_List _uf_map;
+  // Reset the Union-Find map to identity
+  void reset_uf_map( uint maxlrg );
+  // Remove the need for the Union-Find mapping
+  void compress_uf_map_for_nodes( );
+
+  // Combine the Live Range Indices for these 2 Nodes into a single live
+  // range.  Future requests for any Node in either live range will
+  // return the live range index for the combined live range.
+  void Union( const Node *src, const Node *dst );
+
+  void new_lrg( const Node *x, uint lrg );
+
+  // Compact live ranges, removing unused ones.  Return new maxlrg.
+  void compact();
+
+  uint _lo_degree;              // Head of lo-degree LRGs list
+  uint _lo_stk_degree;          // Head of lo-stk-degree LRGs list
+  uint _hi_degree;              // Head of hi-degree LRGs list
+  uint _simplified;             // Linked list head of simplified LRGs
+
+  // Helper functions for Split()
+  uint split_DEF( Node *def, Block *b, int loc, uint max, Node **Reachblock, Node **debug_defs, GrowableArray<uint> splits, int slidx );
+  uint split_USE( Node *def, Block *b, Node *use, uint useidx, uint max, bool def_down, bool cisc_sp, GrowableArray<uint> splits, int slidx );
+  int clone_projs( Block *b, uint idx, Node *con, Node *copy, uint &maxlrg );
+  Node *split_Rematerialize( Node *def, Block *b, uint insidx, uint &maxlrg, GrowableArray<uint> splits, int slidx, uint *lrg2reach, Node **Reachblock, bool walkThru );
+  // True if lidx is used before any real register is def'd in the block
+  bool prompt_use( Block *b, uint lidx );
+  Node *get_spillcopy_wide( Node *def, Node *use, uint uidx );
+  // Insert the spill at chosen location.  Skip over any interveneing Proj's or
+  // Phis.  Skip over a CatchNode and projs, inserting in the fall-through block
+  // instead.  Update high-pressure indices.  Create a new live range.
+  void insert_proj( Block *b, uint i, Node *spill, uint maxlrg );
+
+  bool is_high_pressure( Block *b, LRG *lrg, uint insidx );
+
+  uint _oldphi;                 // Node index which separates pre-allocation nodes
+
+  Block **_blks;                // Array of blocks sorted by frequency for coalescing
+
+#ifndef PRODUCT
+  bool _trace_spilling;
+#endif
+
+public:
+  PhaseChaitin( uint unique, PhaseCFG &cfg, Matcher &matcher );
+  ~PhaseChaitin() {}
+
+  // Convert a Node into a Live Range Index - a lidx
+  uint Find( const Node *n ) {
+    uint lidx = n2lidx(n);
+    uint uf_lidx = _uf_map[lidx];
+    return (uf_lidx == lidx) ? uf_lidx : Find_compress(n);
+  }
+  uint Find_const( uint lrg ) const;
+  uint Find_const( const Node *n ) const;
+
+  // Do all the real work of allocate
+  void Register_Allocate();
+
+  uint n2lidx( const Node *n ) const { return _names[n->_idx]; }
+
+#ifndef PRODUCT
+  bool trace_spilling() const { return _trace_spilling; }
+#endif
+
+private:
+  // De-SSA the world.  Assign registers to Nodes.  Use the same register for
+  // all inputs to a PhiNode, effectively coalescing live ranges.  Insert
+  // copies as needed.
+  void de_ssa();
+  uint Find_compress( const Node *n );
+  uint Find( uint lidx ) {
+    uint uf_lidx = _uf_map[lidx];
+    return (uf_lidx == lidx) ? uf_lidx : Find_compress(lidx);
+  }
+  uint Find_compress( uint lidx );
+
+  uint Find_id( const Node *n ) {
+    uint retval = n2lidx(n);
+    assert(retval == Find(n),"Invalid node to lidx mapping");
+    return retval;
+  }
+
+  // Add edge between reg and everything in the vector.
+  // Same as _ifg->add_vector(reg,live) EXCEPT use the RegMask
+  // information to trim the set of interferences.  Return the
+  // count of edges added.
+  void interfere_with_live( uint reg, IndexSet *live );
+  // Count register pressure for asserts
+  uint count_int_pressure( IndexSet *liveout );
+  uint count_float_pressure( IndexSet *liveout );
+
+  // Build the interference graph using virtual registers only.
+  // Used for aggressive coalescing.
+  void build_ifg_virtual( );
+
+  // Build the interference graph using physical registers when available.
+  // That is, if 2 live ranges are simultaneously alive but in their
+  // acceptable register sets do not overlap, then they do not interfere.
+  uint build_ifg_physical( ResourceArea *a );
+
+  // Gather LiveRanGe information, including register masks and base pointer/
+  // derived pointer relationships.
+  void gather_lrg_masks( bool mod_cisc_masks );
+
+  // Force the bases of derived pointers to be alive at GC points.
+  bool stretch_base_pointer_live_ranges( ResourceArea *a );
+  // Helper to stretch above; recursively discover the base Node for
+  // a given derived Node.  Easy for AddP-related machine nodes, but
+  // needs to be recursive for derived Phis.
+  Node *find_base_for_derived( Node **derived_base_map, Node *derived, uint &maxlrg );
+
+  // Set the was-lo-degree bit.  Conservative coalescing should not change the
+  // colorability of the graph.  If any live range was of low-degree before
+  // coalescing, it should Simplify.  This call sets the was-lo-degree bit.
+  void set_was_low();
+
+  // Split live-ranges that must spill due to register conflicts (as opposed
+  // to capacity spills).  Typically these are things def'd in a register
+  // and used on the stack or vice-versa.
+  void pre_spill();
+
+  // Init LRG caching of degree, numregs.  Init lo_degree list.
+  void cache_lrg_info( );
+
+  // Simplify the IFG by removing LRGs of low degree with no copies
+  void Pre_Simplify();
+
+  // Simplify the IFG by removing LRGs of low degree
+  void Simplify();
+
+  // Select colors by re-inserting edges into the IFG.
+  // Return TRUE if any spills occured.
+  uint Select( );
+  // Helper function for select which allows biased coloring
+  OptoReg::Name choose_color( LRG &lrg, int chunk );
+  // Helper function which implements biasing heuristic
+  OptoReg::Name bias_color( LRG &lrg, int chunk );
+
+  // Split uncolorable live ranges
+  // Return new number of live ranges
+  uint Split( uint maxlrg );
+
+  // Copy 'was_spilled'-edness from one Node to another.
+  void copy_was_spilled( Node *src, Node *dst );
+  // Set the 'spilled_once' or 'spilled_twice' flag on a node.
+  void set_was_spilled( Node *n );
+
+  // Convert ideal spill-nodes into machine loads & stores
+  // Set C->failing when fixup spills could not complete, node limit exceeded.
+  void fixup_spills();
+
+  // Post-Allocation peephole copy removal
+  void post_allocate_copy_removal();
+  Node *skip_copies( Node *c );
+  int yank_if_dead( Node *old, Block *current_block, Node_List *value, Node_List *regnd );
+  int elide_copy( Node *n, int k, Block *current_block, Node_List &value, Node_List &regnd, bool can_change_regs );
+  int use_prior_register( Node *copy, uint idx, Node *def, Block *current_block, Node_List &value, Node_List &regnd );
+  bool may_be_copy_of_callee( Node *def ) const;
+
+  // If nreg already contains the same constant as val then eliminate it
+  bool eliminate_copy_of_constant(Node* val, Block *current_block, Node_List& value, Node_List &regnd,
+                                  OptoReg::Name nreg, OptoReg::Name nreg2);
+  // Extend the node to LRG mapping
+  void add_reference( const Node *node, const Node *old_node);
+
+private:
+
+  static int _final_loads, _final_stores, _final_copies, _final_memoves;
+  static double _final_load_cost, _final_store_cost, _final_copy_cost, _final_memove_cost;
+  static int _conserv_coalesce, _conserv_coalesce_pair;
+  static int _conserv_coalesce_trie, _conserv_coalesce_quad;
+  static int _post_alloc;
+  static int _lost_opp_pp_coalesce, _lost_opp_cflow_coalesce;
+  static int _used_cisc_instructions, _unused_cisc_instructions;
+  static int _allocator_attempts, _allocator_successes;
+
+#ifndef PRODUCT
+  static uint _high_pressure, _low_pressure;
+
+  void dump() const;
+  void dump( const Node *n ) const;
+  void dump( const Block * b ) const;
+  void dump_degree_lists() const;
+  void dump_simplified() const;
+  void dump_lrg( uint lidx ) const;
+  void dump_bb( uint pre_order ) const;
+
+  // Verify that base pointers and derived pointers are still sane
+  void verify_base_ptrs( ResourceArea *a ) const;
+
+  void dump_for_spill_split_recycle() const;
+
+public:
+  void dump_frame() const;
+  char *dump_register( const Node *n, char *buf  ) const;
+private:
+  static void print_chaitin_statistics();
+#endif
+  friend class PhaseCoalesce;
+  friend class PhaseAggressiveCoalesce;
+  friend class PhaseConservativeCoalesce;
+};