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 3, 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 COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef GCC_DDG_H
  23 #define GCC_DDG_H
  24
  25 /* For sbitmap.  */
  26 #include "sbitmap.h"
  27 /* For basic_block.  */
  28 #include "basic-block.h"
  29 #include "df.h"
  30
  31 typedef struct ddg_node *ddg_node_ptr;
  32 typedef struct ddg_edge *ddg_edge_ptr;
  33 typedef struct ddg *ddg_ptr;
  34 typedef struct ddg_scc *ddg_scc_ptr;
  35 typedef struct ddg_all_sccs *ddg_all_sccs_ptr;
  36
  37 typedef enum {TRUE_DEP, OUTPUT_DEP, ANTI_DEP} dep_type;
  38 typedef enum {REG_OR_MEM_DEP, REG_DEP, MEM_DEP, REG_AND_MEM_DEP}
  39              dep_data_type;
  40
  41 /* The following two macros enables direct access to the successors and
  42    predecessors bitmaps held in each ddg_node.  Do not make changes to
  43    these bitmaps, unless you want to change the DDG.  */
  44 #define NODE_SUCCESSORS(x)  ((x)->successors)
  45 #define NODE_PREDECESSORS(x)  ((x)->predecessors)
  46
  47 /* A structure that represents a node in the DDG.  */
  48 struct ddg_node
  49 {
  50   /* Each node has a unique CUID index.  These indices increase monotonically
  51      (according to the order of the corresponding INSN in the BB), starting
  52      from 0 with no gaps.  */
  53   int cuid;
  54
  55   /* The insn represented by the node.  */
  56   rtx insn;
  57
  58   /* A note preceding INSN (or INSN itself), such that all insns linked
  59      from FIRST_NOTE until INSN (inclusive of both) are moved together
  60      when reordering the insns.  This takes care of notes that should
  61      continue to precede INSN.  */
  62   rtx first_note;
  63
  64   /* Incoming and outgoing dependency edges.  */
  65   ddg_edge_ptr in;
  66   ddg_edge_ptr out;
  67
  68   /* Each bit corresponds to a ddg_node according to its cuid, and is
  69      set iff the node is a successor/predecessor of "this" node.  */
  70   sbitmap successors;
  71   sbitmap predecessors;
  72
  73   /* For general use by algorithms manipulating the ddg.  */
  74   union {
  75     int count;
  76     void *info;
  77   } aux;
  78 };
  79
  80 /* A structure that represents an edge in the DDG.  */
  81 struct ddg_edge
  82 {
  83   /* The source and destination nodes of the dependency edge.  */
  84   ddg_node_ptr src;
  85   ddg_node_ptr dest;
  86
  87   /* TRUE, OUTPUT or ANTI dependency.  */
  88   dep_type type;
  89
  90   /* REG or MEM dependency.  */
  91   dep_data_type data_type;
  92
  93   /* Latency of the dependency.  */
  94   int latency;
  95
  96   /* The distance: number of loop iterations the dependency crosses.  */
  97   int distance;
  98
  99   /* The following two fields are used to form a linked list of the in/out
 100      going edges to/from each node.  */
 101   ddg_edge_ptr next_in;
 102   ddg_edge_ptr next_out;
 103
 104   /* For general use by algorithms manipulating the ddg.  */
 105   union {
 106     int count;
 107     void *info;
 108   } aux;
 109 };
 110
 111 /* This structure holds the Data Dependence Graph for a basic block.  */
 112 struct ddg
 113 {
 114   /* The basic block for which this DDG is built.  */
 115   basic_block bb;
 116
 117   /* Number of instructions in the basic block.  */
 118   int num_nodes;
 119
 120   /* Number of load/store instructions in the BB - statistics.  */
 121   int num_loads;
 122   int num_stores;
 123
 124   /* This array holds the nodes in the graph; it is indexed by the node
 125      cuid, which follows the order of the instructions in the BB.  */
 126   ddg_node_ptr nodes;
 127
 128   /* The branch closing the loop.  */
 129   ddg_node_ptr closing_branch;
 130
 131   /* Build dependence edges for closing_branch, when set.  In certain cases,
 132      the closing branch can be dealt with separately from the insns of the
 133      loop, and then no such deps are needed.  */
 134   int closing_branch_deps;
 135
 136   /* Array and number of backarcs (edges with distance > 0) in the DDG.  */
 137   ddg_edge_ptr *backarcs;
 138   int num_backarcs;
 139 };
 140
 141 \f
 142 /* Holds information on an SCC (Strongly Connected Component) of the DDG.  */
 143 struct ddg_scc
 144 {
 145   /* A bitmap that represents the nodes of the DDG that are in the SCC.  */
 146   sbitmap nodes;
 147
 148   /* Array and number of backarcs (edges with distance > 0) in the SCC.  */
 149   ddg_edge_ptr *backarcs;
 150   int num_backarcs;
 151
 152   /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */
 153   int recurrence_length;
 154 };
 155
 156 /* This structure holds the SCCs of the DDG.  */
 157 struct ddg_all_sccs
 158 {
 159   /* Array that holds the SCCs in the DDG, and their number.  */
 160   ddg_scc_ptr *sccs;
 161   int num_sccs;
 162
 163   ddg_ptr ddg;
 164 };
 165
 166 \f
 167 ddg_ptr create_ddg (basic_block, int closing_branch_deps);
 168 void free_ddg (ddg_ptr);
 169
 170 void print_ddg (FILE *, ddg_ptr);
 171 void vcg_print_ddg (FILE *, ddg_ptr);
 172 void print_ddg_edge (FILE *, ddg_edge_ptr);
 173 void print_sccs (FILE *, ddg_all_sccs_ptr, ddg_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 */