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, 51 Franklin Street, Fifth Floor, Boston, MA
  21 02110-1301, USA.  */
  22
  23 #ifndef GCC_DDG_H
  24 #define GCC_DDG_H
  25
  26 /* For sbitmap.  */
  27 #include "sbitmap.h"
  28 /* For basic_block.  */
  29 #include "basic-block.h"
  30 /* For struct df.  */
  31 #include "df.h"
  32
  33 typedef struct ddg_node *ddg_node_ptr;
  34 typedef struct ddg_edge *ddg_edge_ptr;
  35 typedef struct ddg *ddg_ptr;
  36 typedef struct ddg_scc *ddg_scc_ptr;
  37 typedef struct ddg_all_sccs *ddg_all_sccs_ptr;
  38
  39 typedef enum {TRUE_DEP, OUTPUT_DEP, ANTI_DEP} dep_type;
  40 typedef enum {REG_OR_MEM_DEP, REG_DEP, MEM_DEP, REG_AND_MEM_DEP}
  41              dep_data_type;
  42
  43 /* The following two macros enables direct access to the successors and
  44    predecessors bitmaps held in each ddg_node.  Do not make changes to
  45    these bitmaps, unless you want to change the DDG.  */
  46 #define NODE_SUCCESSORS(x)  ((x)->successors)
  47 #define NODE_PREDECESSORS(x)  ((x)->predecessors)
  48
  49 /* A structure that represents a node in the DDG.  */
  50 struct ddg_node
  51 {
  52   /* Each node has a unique CUID index.  These indices increase monotonically
  53      (according to the order of the corresponding INSN in the BB), starting
  54      from 0 with no gaps.  */
  55   int cuid;
  56
  57   /* The insn represented by the node.  */
  58   rtx insn;
  59
  60   /* A note preceding INSN (or INSN itself), such that all insns linked
  61      from FIRST_NOTE until INSN (inclusive of both) are moved together
  62      when reordering the insns.  This takes care of notes that should
  63      continue to precede INSN.  */
  64   rtx first_note;
  65
  66   /* Incoming and outgoing dependency edges.  */
  67   ddg_edge_ptr in;
  68   ddg_edge_ptr out;
  69
  70   /* Each bit corresponds to a ddg_node according to its cuid, and is
  71      set iff the node is a successor/predecessor of "this" node.  */
  72   sbitmap successors;
  73   sbitmap predecessors;
  74
  75   /* For general use by algorithms manipulating the ddg.  */
  76   union {
  77     int count;
  78     void *info;
  79   } aux;
  80 };
  81
  82 /* A structure that represents an edge in the DDG.  */
  83 struct ddg_edge
  84 {
  85   /* The source and destination nodes of the dependency edge.  */
  86   ddg_node_ptr src;
  87   ddg_node_ptr dest;
  88
  89   /* TRUE, OUTPUT or ANTI dependency.  */
  90   dep_type type;
  91
  92   /* REG or MEM dependency.  */
  93   dep_data_type data_type;
  94
  95   /* Latency of the dependency.  */
  96   int latency;
  97
  98   /* The distance: number of loop iterations the dependency crosses.  */
  99   int distance;
 100
 101   /* The following two fields are used to form a linked list of the in/out
 102      going edges to/from each node.  */
 103   ddg_edge_ptr next_in;
 104   ddg_edge_ptr next_out;
 105
 106   /* For general use by algorithms manipulating the ddg.  */
 107   union {
 108     int count;
 109     void *info;
 110   } aux;
 111 };
 112
 113 /* This structure holds the Data Dependence Graph for a basic block.  */
 114 struct ddg
 115 {
 116   /* The basic block for which this DDG is built.  */
 117   basic_block bb;
 118
 119   /* Number of instructions in the basic block.  */
 120   int num_nodes;
 121
 122   /* Number of load/store instructions in the BB - statistics.  */
 123   int num_loads;
 124   int num_stores;
 125
 126   /* This array holds the nodes in the graph; it is indexed by the node
 127      cuid, which follows the order of the instructions in the BB.  */
 128   ddg_node_ptr nodes;
 129
 130   /* The branch closing the loop.  */
 131   ddg_node_ptr closing_branch;
 132
 133   /* Build dependence edges for closing_branch, when set.  In certain cases,
 134      the closing branch can be dealt with separately from the insns of the
 135      loop, and then no such deps are needed.  */
 136   int closing_branch_deps;
 137
 138   /* Array and number of backarcs (edges with distance > 0) in the DDG.  */
 139   ddg_edge_ptr *backarcs;
 140   int num_backarcs;
 141 };
 142
 143 \f
 144 /* Holds information on an SCC (Strongly Connected Component) of the DDG.  */
 145 struct ddg_scc
 146 {
 147   /* A bitmap that represents the nodes of the DDG that are in the SCC.  */
 148   sbitmap nodes;
 149
 150   /* Array and number of backarcs (edges with distance > 0) in the SCC.  */
 151   ddg_edge_ptr *backarcs;
 152   int num_backarcs;
 153
 154   /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */
 155   int recurrence_length;
 156 };
 157
 158 /* This structure holds the SCCs of the DDG.  */
 159 struct ddg_all_sccs
 160 {
 161   /* Array that holds the SCCs in the DDG, and their number.  */
 162   ddg_scc_ptr *sccs;
 163   int num_sccs;
 164
 165   ddg_ptr ddg;
 166 };
 167
 168 \f
 169 ddg_ptr create_ddg (basic_block, struct df *, int closing_branch_deps);
 170 void free_ddg (ddg_ptr);
 171
 172 void print_ddg (FILE *, ddg_ptr);
 173 void vcg_print_ddg (FILE *, ddg_ptr);
 174 void print_ddg_edge (FILE *, ddg_edge_ptr);
 175
 176 ddg_node_ptr get_node_of_insn (ddg_ptr, rtx);
 177
 178 void find_successors (sbitmap result, ddg_ptr, sbitmap);
 179 void find_predecessors (sbitmap result, ddg_ptr, sbitmap);
 180
 181 ddg_all_sccs_ptr create_ddg_all_sccs (ddg_ptr);
 182 void free_ddg_all_sccs (ddg_all_sccs_ptr);
 183
 184 int find_nodes_on_paths (sbitmap result, ddg_ptr, sbitmap from, sbitmap to);
 185 int longest_simple_path (ddg_ptr, int from, int to, sbitmap via);
 186
 187 #endif /* GCC_DDG_H */