1/* DDG - Data Dependence Graph - interface.
2   Copyright (C) 2004-2015 Free Software Foundation, Inc.
3   Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.com>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3.  If not see
19<http://www.gnu.org/licenses/>.  */
20
21#ifndef GCC_DDG_H
22#define GCC_DDG_H
23
24/* For sbitmap.  */
25
26typedef struct ddg_node *ddg_node_ptr;
27typedef struct ddg_edge *ddg_edge_ptr;
28typedef struct ddg *ddg_ptr;
29typedef struct ddg_scc *ddg_scc_ptr;
30typedef struct ddg_all_sccs *ddg_all_sccs_ptr;
31
32enum dep_type {TRUE_DEP, OUTPUT_DEP, ANTI_DEP};
33enum dep_data_type {REG_OR_MEM_DEP, REG_DEP, MEM_DEP, REG_AND_MEM_DEP};
34
35/* The following two macros enables direct access to the successors and
36   predecessors bitmaps held in each ddg_node.  Do not make changes to
37   these bitmaps, unless you want to change the DDG.  */
38#define NODE_SUCCESSORS(x)  ((x)->successors)
39#define NODE_PREDECESSORS(x)  ((x)->predecessors)
40
41/* A structure that represents a node in the DDG.  */
42struct ddg_node
43{
44  /* Each node has a unique CUID index.  These indices increase monotonically
45     (according to the order of the corresponding INSN in the BB), starting
46     from 0 with no gaps.  */
47  int cuid;
48
49  /* The insn represented by the node.  */
50  rtx_insn *insn;
51
52  /* A note preceding INSN (or INSN itself), such that all insns linked
53     from FIRST_NOTE until INSN (inclusive of both) are moved together
54     when reordering the insns.  This takes care of notes that should
55     continue to precede INSN.  */
56  rtx_insn *first_note;
57
58  /* Incoming and outgoing dependency edges.  */
59  ddg_edge_ptr in;
60  ddg_edge_ptr out;
61
62  /* Each bit corresponds to a ddg_node according to its cuid, and is
63     set iff the node is a successor/predecessor of "this" node.  */
64  sbitmap successors;
65  sbitmap predecessors;
66
67  /* For general use by algorithms manipulating the ddg.  */
68  union {
69    int count;
70    void *info;
71  } aux;
72};
73
74/* A structure that represents an edge in the DDG.  */
75struct ddg_edge
76{
77  /* The source and destination nodes of the dependency edge.  */
78  ddg_node_ptr src;
79  ddg_node_ptr dest;
80
81  /* TRUE, OUTPUT or ANTI dependency.  */
82  dep_type type;
83
84  /* REG or MEM dependency.  */
85  dep_data_type data_type;
86
87  /* Latency of the dependency.  */
88  int latency;
89
90  /* The distance: number of loop iterations the dependency crosses.  */
91  int distance;
92
93  /* The following two fields are used to form a linked list of the in/out
94     going edges to/from each node.  */
95  ddg_edge_ptr next_in;
96  ddg_edge_ptr next_out;
97
98  /* For general use by algorithms manipulating the ddg.  */
99  union {
100    int count;
101    void *info;
102  } aux;
103};
104
105/* This structure holds the Data Dependence Graph for a basic block.  */
106struct ddg
107{
108  /* The basic block for which this DDG is built.  */
109  basic_block bb;
110
111  /* Number of instructions in the basic block.  */
112  int num_nodes;
113
114  /* Number of load/store instructions in the BB - statistics.  */
115  int num_loads;
116  int num_stores;
117
118  /* Number of debug instructions in the BB.  */
119  int num_debug;
120
121  /* This array holds the nodes in the graph; it is indexed by the node
122     cuid, which follows the order of the instructions in the BB.  */
123  ddg_node_ptr nodes;
124
125  /* The branch closing the loop.  */
126  ddg_node_ptr closing_branch;
127
128  /* Build dependence edges for closing_branch, when set.  In certain cases,
129     the closing branch can be dealt with separately from the insns of the
130     loop, and then no such deps are needed.  */
131  int closing_branch_deps;
132
133  /* Array and number of backarcs (edges with distance > 0) in the DDG.  */
134  int num_backarcs;
135  ddg_edge_ptr *backarcs;
136};
137
138
139/* Holds information on an SCC (Strongly Connected Component) of the DDG.  */
140struct ddg_scc
141{
142  /* A bitmap that represents the nodes of the DDG that are in the SCC.  */
143  sbitmap nodes;
144
145  /* Array and number of backarcs (edges with distance > 0) in the SCC.  */
146  ddg_edge_ptr *backarcs;
147  int num_backarcs;
148
149  /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */
150  int recurrence_length;
151};
152
153/* This structure holds the SCCs of the DDG.  */
154struct ddg_all_sccs
155{
156  /* Array that holds the SCCs in the DDG, and their number.  */
157  ddg_scc_ptr *sccs;
158  int num_sccs;
159
160  ddg_ptr ddg;
161};
162
163
164ddg_ptr create_ddg (basic_block, int closing_branch_deps);
165void free_ddg (ddg_ptr);
166
167void print_ddg (FILE *, ddg_ptr);
168void vcg_print_ddg (FILE *, ddg_ptr);
169void print_ddg_edge (FILE *, ddg_edge_ptr);
170void print_sccs (FILE *, ddg_all_sccs_ptr, ddg_ptr);
171
172ddg_node_ptr get_node_of_insn (ddg_ptr, rtx_insn *);
173
174void find_successors (sbitmap result, ddg_ptr, sbitmap);
175void find_predecessors (sbitmap result, ddg_ptr, sbitmap);
176
177ddg_all_sccs_ptr create_ddg_all_sccs (ddg_ptr);
178void free_ddg_all_sccs (ddg_all_sccs_ptr);
179
180int find_nodes_on_paths (sbitmap result, ddg_ptr, sbitmap from, sbitmap to);
181int longest_simple_path (ddg_ptr, int from, int to, sbitmap via);
182
183bool autoinc_var_is_used_p (rtx_insn *, rtx_insn *);
184
185#endif /* GCC_DDG_H */
186