gcc/ddg.h

   1 /* DDG - Data Dependence Graph - interface.
   2    Copyright (C) 2004
   3    Free Software Foundation, Inc.
   4    Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to the Free
  20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  21 02111-1307, USA.  */
  22
  23 #ifndef GCC_DDG_H
  24 #define GCC_DDG_H
  25
  26
  27 typedef struct ddg_node *ddg_node_ptr;
  28 typedef struct ddg_edge *ddg_edge_ptr;
  29 typedef struct ddg *ddg_ptr;
  30 typedef struct ddg_scc *ddg_scc_ptr;
  31 typedef struct ddg_all_sccs *ddg_all_sccs_ptr;
  32
  33 typedef enum {TRUE_DEP, OUTPUT_DEP, ANTI_DEP} dep_type;
  34 typedef enum {REG_OR_MEM_DEP, REG_DEP, MEM_DEP, REG_AND_MEM_DEP}
  35              dep_data_type;
  36
  37 /* The following two macros enables direct access to the successors and
  38    predecessors bitmaps held in each ddg_node.  Do not make changes to
  39    these bitmaps, unless you want to change the DDG.  */
  40 #define NODE_SUCCESSORS(x)  ((x)->successors)
  41 #define NODE_PREDECESSORS(x)  ((x)->predecessors)
  42
  43 /* A structure that represents a node in the DDG.  */
  44 struct ddg_node
  45 {
  46   /* Each node has a unique CUID index.  These indices increase monotonically
  47      (according to the order of the corresponding INSN in the BB), starting
  48      from 0 with no gaps.  */
  49   int cuid;
  50
  51   /* The insn represented by the node.  */
  52   rtx insn;
  53
  54   /* A note preceeding INSN (or INSN itself), such that all insns linked
  55      from FIRST_NOTE until INSN (inclusive of both) are moved together
  56      when reordering the insns.  This takes care of notes that should
  57      continue to preceed INSN.  */
  58   rtx first_note;
  59
  60   /* Incoming and outgoing dependency edges.  */
  61   ddg_edge_ptr in;
  62   ddg_edge_ptr out;
  63
  64   /* Each bit corresponds to a ddg_node according to its cuid, and is
  65      set iff the node is a successor/predecessor of "this" node.  */
  66   sbitmap successors;
  67   sbitmap predecessors;
  68
  69   /* For general use by algorithms manipulating the ddg.  */
  70   union {
  71     int count;
  72     void *info;
  73   } aux;
  74 };
  75
  76 /* A structure that represents an edge in the DDG.  */
  77 struct ddg_edge
  78 {
  79   /* The source and destination nodes of the dependency edge.  */
  80   ddg_node_ptr src;
  81   ddg_node_ptr dest;
  82
  83   /* TRUE, OUTPUT or ANTI dependency.  */
  84   dep_type type;
  85
  86   /* REG or MEM dependency.  */
  87   dep_data_type data_type;
  88
  89   /* Latency of the depedency.  */
  90   int latency;
  91
  92   /* The distance: number of loop iterations the dependency crosses.  */
  93   int distance;
  94
  95   /* The following two fields are used to form a linked list of the in/out
  96      going edges to/from each node.  */
  97   ddg_edge_ptr next_in;
  98   ddg_edge_ptr next_out;
  99
 100   /* For general use by algorithms manipulating the ddg.  */
 101   union {
 102     int count;
 103     void *info;
 104   } aux;
 105 };
 106
 107 /* This structure holds the Data Dependence Graph for a basic block.  */
 108 struct ddg
 109 {
 110   /* The basic block for which this DDG is built.  */
 111   basic_block bb;
 112
 113   /* Number of instructions in the basic block.  */
 114   int num_nodes;
 115
 116   /* Number of load/store instructions in the BB - statistics.  */
 117   int num_loads;
 118   int num_stores;
 119
 120   /* This array holds the nodes in the graph; it is indexed by the node
 121      cuid, which follows the order of the instructions in the BB.  */
 122   ddg_node_ptr nodes;
 123
 124   /* The branch closing the loop.  */
 125   ddg_node_ptr closing_branch;
 126
 127   /* Build dependence edges for closing_branch, when set.  In certain cases,
 128      the closing branch can be dealt with separately from the insns of the
 129      loop, and then no such deps are needed.  */
 130   int closing_branch_deps;
 131
 132   /* Array and number of backarcs (edges with distance > 0) in the DDG.  */
 133   ddg_edge_ptr *backarcs;
 134   int num_backarcs;
 135 };
 136
 137 \f
 138 /* Holds information on an SCC (Strongly Connected Component) of the DDG.  */
 139 struct ddg_scc
 140 {
 141   /* A bitmap that represents the nodes of the DDG that are in the SCC.  */
 142   sbitmap nodes;
 143
 144   /* Array and number of backarcs (edges with distance > 0) in the SCC.  */
 145   ddg_edge_ptr *backarcs;
 146   int num_backarcs;
 147
 148   /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */
 149   int recurrence_length;
 150 };
 151
 152 /* This structure holds the SCCs of the DDG.  */
 153 struct ddg_all_sccs
 154 {
 155   /* Array that holds the SCCs in the DDG, and their number.  */
 156   ddg_scc_ptr *sccs;
 157   int num_sccs;
 158
 159   ddg_ptr ddg;
 160 };
 161
 162 \f
 163 ddg_ptr create_ddg (basic_block, struct df *, int closing_branch_deps);
 164 void free_ddg (ddg_ptr);
 165
 166 void print_ddg (FILE *, ddg_ptr);
 167 void vcg_print_ddg (FILE *, ddg_ptr);
 168 void print_ddg_edge (FILE *, ddg_edge_ptr);
 169
 170 ddg_node_ptr get_node_of_insn (ddg_ptr, rtx);
 171
 172 void find_successors (sbitmap result, ddg_ptr, sbitmap);
 173 void find_predecessors (sbitmap result, ddg_ptr, sbitmap);
 174
 175 ddg_all_sccs_ptr create_ddg_all_sccs (ddg_ptr);
 176 void free_ddg_all_sccs (ddg_all_sccs_ptr);
 177
 178 int find_nodes_on_paths (sbitmap result, ddg_ptr, sbitmap from, sbitmap to);
 179 int longest_simple_path (ddg_ptr, int from, int to, sbitmap via);
 180
 181 #endif /* GCC_DDG_H */