gcc/ddg.h

   1 /* DDG - Data Dependence Graph - interface.
   2    Copyright (C) 2004, 2005, 2006, 2007
   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 #include "df.h"
  31
  32 typedef struct ddg_node *ddg_node_ptr;
  33 typedef struct ddg_edge *ddg_edge_ptr;
  34 typedef struct ddg *ddg_ptr;
  35 typedef struct ddg_scc *ddg_scc_ptr;
  36 typedef struct ddg_all_sccs *ddg_all_sccs_ptr;
  37
  38 typedef enum {TRUE_DEP, OUTPUT_DEP, ANTI_DEP} dep_type;
  39 typedef enum {REG_OR_MEM_DEP, REG_DEP, MEM_DEP, REG_AND_MEM_DEP}
  40              dep_data_type;
  41
  42 /* The following two macros enables direct access to the successors and
  43    predecessors bitmaps held in each ddg_node.  Do not make changes to
  44    these bitmaps, unless you want to change the DDG.  */
  45 #define NODE_SUCCESSORS(x)  ((x)->successors)
  46 #define NODE_PREDECESSORS(x)  ((x)->predecessors)
  47
  48 /* A structure that represents a node in the DDG.  */
  49 struct ddg_node
  50 {
  51   /* Each node has a unique CUID index.  These indices increase monotonically
  52      (according to the order of the corresponding INSN in the BB), starting
  53      from 0 with no gaps.  */
  54   int cuid;
  55
  56   /* The insn represented by the node.  */
  57   rtx insn;
  58
  59   /* A note preceding INSN (or INSN itself), such that all insns linked
  60      from FIRST_NOTE until INSN (inclusive of both) are moved together
  61      when reordering the insns.  This takes care of notes that should
  62      continue to precede INSN.  */
  63   rtx first_note;
  64
  65   /* Incoming and outgoing dependency edges.  */
  66   ddg_edge_ptr in;
  67   ddg_edge_ptr out;
  68
  69   /* Each bit corresponds to a ddg_node according to its cuid, and is
  70      set iff the node is a successor/predecessor of "this" node.  */
  71   sbitmap successors;
  72   sbitmap predecessors;
  73
  74   /* For general use by algorithms manipulating the ddg.  */
  75   union {
  76     int count;
  77     void *info;
  78   } aux;
  79 };
  80
  81 /* A structure that represents an edge in the DDG.  */
  82 struct ddg_edge
  83 {
  84   /* The source and destination nodes of the dependency edge.  */
  85   ddg_node_ptr src;
  86   ddg_node_ptr dest;
  87
  88   /* TRUE, OUTPUT or ANTI dependency.  */
  89   dep_type type;
  90
  91   /* REG or MEM dependency.  */
  92   dep_data_type data_type;
  93
  94   /* Latency of the dependency.  */
  95   int latency;
  96
  97   /* The distance: number of loop iterations the dependency crosses.  */
  98   int distance;
  99
 100   /* The following two fields are used to form a linked list of the in/out
 101      going edges to/from each node.  */
 102   ddg_edge_ptr next_in;
 103   ddg_edge_ptr next_out;
 104
 105   /* For general use by algorithms manipulating the ddg.  */
 106   union {
 107     int count;
 108     void *info;
 109   } aux;
 110 };
 111
 112 /* This structure holds the Data Dependence Graph for a basic block.  */
 113 struct ddg
 114 {
 115   /* The basic block for which this DDG is built.  */
 116   basic_block bb;
 117
 118   /* Number of instructions in the basic block.  */
 119   int num_nodes;
 120
 121   /* Number of load/store instructions in the BB - statistics.  */
 122   int num_loads;
 123   int num_stores;
 124
 125   /* This array holds the nodes in the graph; it is indexed by the node
 126      cuid, which follows the order of the instructions in the BB.  */
 127   ddg_node_ptr nodes;
 128
 129   /* The branch closing the loop.  */
 130   ddg_node_ptr closing_branch;
 131
 132   /* Build dependence edges for closing_branch, when set.  In certain cases,
 133      the closing branch can be dealt with separately from the insns of the
 134      loop, and then no such deps are needed.  */
 135   int closing_branch_deps;
 136
 137   /* Array and number of backarcs (edges with distance > 0) in the DDG.  */
 138   ddg_edge_ptr *backarcs;
 139   int num_backarcs;
 140 };
 141
 142 \f
 143 /* Holds information on an SCC (Strongly Connected Component) of the DDG.  */
 144 struct ddg_scc
 145 {
 146   /* A bitmap that represents the nodes of the DDG that are in the SCC.  */
 147   sbitmap nodes;
 148
 149   /* Array and number of backarcs (edges with distance > 0) in the SCC.  */
 150   ddg_edge_ptr *backarcs;
 151   int num_backarcs;
 152
 153   /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */
 154   int recurrence_length;
 155 };
 156
 157 /* This structure holds the SCCs of the DDG.  */
 158 struct ddg_all_sccs
 159 {
 160   /* Array that holds the SCCs in the DDG, and their number.  */
 161   ddg_scc_ptr *sccs;
 162   int num_sccs;
 163
 164   ddg_ptr ddg;
 165 };
 166
 167 \f
 168 ddg_ptr create_ddg (basic_block, int closing_branch_deps);
 169 void free_ddg (ddg_ptr);
 170
 171 void print_ddg (FILE *, ddg_ptr);
 172 void vcg_print_ddg (FILE *, ddg_ptr);
 173 void print_ddg_edge (FILE *, ddg_edge_ptr);
 174
 175 ddg_node_ptr get_node_of_insn (ddg_ptr, rtx);
 176
 177 void find_successors (sbitmap result, ddg_ptr, sbitmap);
 178 void find_predecessors (sbitmap result, ddg_ptr, sbitmap);
 179
 180 ddg_all_sccs_ptr create_ddg_all_sccs (ddg_ptr);
 181 void free_ddg_all_sccs (ddg_all_sccs_ptr);
 182
 183 int find_nodes_on_paths (sbitmap result, ddg_ptr, sbitmap from, sbitmap to);
 184 int longest_simple_path (ddg_ptr, int from, int to, sbitmap via);
 185
 186 #endif /* GCC_DDG_H */