1/* DDG - Data Dependence Graph - interface.
2   Copyright (C) 2004, 2005, 2006, 2007, 2008
3   Free Software Foundation, Inc.
4   Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.com>
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 3, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16for more details.
17
18You should have received a copy of the GNU General Public License
19along 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
31typedef struct ddg_node *ddg_node_ptr;
32typedef struct ddg_edge *ddg_edge_ptr;
33typedef struct ddg *ddg_ptr;
34typedef struct ddg_scc *ddg_scc_ptr;
35typedef struct ddg_all_sccs *ddg_all_sccs_ptr;
36
37typedef enum {TRUE_DEP, OUTPUT_DEP, ANTI_DEP} dep_type;
38typedef 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.  */
48struct 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.  */
81struct 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.  */
112struct 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  /* Number of debug instructions in the BB.  */
125  int num_debug;
126
127  /* This array holds the nodes in the graph; it is indexed by the node
128     cuid, which follows the order of the instructions in the BB.  */
129  ddg_node_ptr nodes;
130
131  /* The branch closing the loop.  */
132  ddg_node_ptr closing_branch;
133
134  /* Build dependence edges for closing_branch, when set.  In certain cases,
135     the closing branch can be dealt with separately from the insns of the
136     loop, and then no such deps are needed.  */
137  int closing_branch_deps;
138
139  /* Array and number of backarcs (edges with distance > 0) in the DDG.  */
140  int num_backarcs;
141  ddg_edge_ptr *backarcs;
142};
143
144
145/* Holds information on an SCC (Strongly Connected Component) of the DDG.  */
146struct ddg_scc
147{
148  /* A bitmap that represents the nodes of the DDG that are in the SCC.  */
149  sbitmap nodes;
150
151  /* Array and number of backarcs (edges with distance > 0) in the SCC.  */
152  ddg_edge_ptr *backarcs;
153  int num_backarcs;
154
155  /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */
156  int recurrence_length;
157};
158
159/* This structure holds the SCCs of the DDG.  */
160struct ddg_all_sccs
161{
162  /* Array that holds the SCCs in the DDG, and their number.  */
163  ddg_scc_ptr *sccs;
164  int num_sccs;
165
166  ddg_ptr ddg;
167};
168
169
170ddg_ptr create_ddg (basic_block, int closing_branch_deps);
171void free_ddg (ddg_ptr);
172
173void print_ddg (FILE *, ddg_ptr);
174void vcg_print_ddg (FILE *, ddg_ptr);
175void print_ddg_edge (FILE *, ddg_edge_ptr);
176void print_sccs (FILE *, ddg_all_sccs_ptr, ddg_ptr);
177
178ddg_node_ptr get_node_of_insn (ddg_ptr, rtx);
179
180void find_successors (sbitmap result, ddg_ptr, sbitmap);
181void find_predecessors (sbitmap result, ddg_ptr, sbitmap);
182
183ddg_all_sccs_ptr create_ddg_all_sccs (ddg_ptr);
184void free_ddg_all_sccs (ddg_all_sccs_ptr);
185
186int find_nodes_on_paths (sbitmap result, ddg_ptr, sbitmap from, sbitmap to);
187int longest_simple_path (ddg_ptr, int from, int to, sbitmap via);
188
189#endif /* GCC_DDG_H */
190