1 /* Calculate branch probabilities, and basic block execution counts.
2 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
4 Contributed by James E. Wilson, UC Berkeley/Cygnus Support;
5 based on some ideas from Dain Samples of UC Berkeley.
6 Further mangling by Bob Manson, Cygnus Support.
7 Converted to use trees by Dale Johannesen, Apple Computer.
9 This file is part of GCC.
11 GCC is free software; you can redistribute it and/or modify it under
12 the terms of the GNU General Public License as published by the Free
13 Software Foundation; either version 2, or (at your option) any later
16 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
17 WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
21 You should have received a copy of the GNU General Public License
22 along with GCC; see the file COPYING. If not, write to the Free
23 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
26 /* Generate basic block profile instrumentation and auxiliary files.
27 Profile generation is optimized, so that not all arcs in the basic
28 block graph need instrumenting. First, the BB graph is closed with
29 one entry (function start), and one exit (function exit). Any
30 ABNORMAL_EDGE cannot be instrumented (because there is no control
31 path to place the code). We close the graph by inserting fake
32 EDGE_FAKE edges to the EXIT_BLOCK, from the sources of abnormal
33 edges that do not go to the exit_block. We ignore such abnormal
34 edges. Naturally these fake edges are never directly traversed,
35 and so *cannot* be directly instrumented. Some other graph
36 massaging is done. To optimize the instrumentation we generate the
37 BB minimal span tree, only edges that are not on the span tree
38 (plus the entry point) need instrumenting. From that information
39 all other edge counts can be deduced. By construction all fake
40 edges must be on the spanning tree. We also attempt to place
41 EDGE_CRITICAL edges on the spanning tree.
43 The auxiliary file generated is <dumpbase>.bbg. The format is
44 described in full in gcov-io.h. */
46 /* ??? Register allocation should use basic block execution counts to
47 give preference to the most commonly executed blocks. */
49 /* ??? Should calculate branch probabilities before instrumenting code, since
50 then we can use arc counts to help decide which arcs to instrument. */
54 #include "coretypes.h"
65 #include "tree-flow.h"
66 #include "tree-dump.h"
67 #include "tree-pass.h"
69 #include "value-prof.h"
72 /* Output instructions as GIMPLE trees to increment the edge
73 execution count, and insert them on E. We rely on
74 bsi_insert_on_edge to preserve the order. */
77 tree_gen_edge_profiler (int edgeno
, edge e
)
79 tree tmp1
= create_tmp_var (GCOV_TYPE_NODE
, "PROF");
80 tree tmp2
= create_tmp_var (GCOV_TYPE_NODE
, "PROF");
81 tree ref
= tree_coverage_counter_ref (GCOV_COUNTER_ARCS
, edgeno
);
82 tree stmt1
= build (MODIFY_EXPR
, GCOV_TYPE_NODE
, tmp1
, ref
);
83 tree stmt2
= build (MODIFY_EXPR
, GCOV_TYPE_NODE
, tmp2
,
84 build (PLUS_EXPR
, GCOV_TYPE_NODE
,
85 tmp1
, integer_one_node
));
86 tree stmt3
= build (MODIFY_EXPR
, GCOV_TYPE_NODE
, ref
, tmp2
);
87 bsi_insert_on_edge (e
, stmt1
);
88 bsi_insert_on_edge (e
, stmt2
);
89 bsi_insert_on_edge (e
, stmt3
);
92 /* Output instructions as GIMPLE trees to increment the interval histogram
93 counter. VALUE is the expression whose value is profiled. TAG is the
94 tag of the section for counters, BASE is offset of the counter position. */
97 tree_gen_interval_profiler (struct histogram_value
*value ATTRIBUTE_UNUSED
,
98 unsigned tag ATTRIBUTE_UNUSED
,
99 unsigned base ATTRIBUTE_UNUSED
)
101 /* FIXME implement this. */
105 /* Output instructions as GIMPLE trees to increment the power of two histogram
106 counter. VALUE is the expression whose value is profiled. TAG is the tag
107 of the section for counters, BASE is offset of the counter position. */
110 tree_gen_pow2_profiler (struct histogram_value
*value ATTRIBUTE_UNUSED
,
111 unsigned tag ATTRIBUTE_UNUSED
,
112 unsigned base ATTRIBUTE_UNUSED
)
114 /* FIXME implement this. */
118 /* Output instructions as GIMPLE trees for code to find the most common value.
119 VALUE is the expression whose value is profiled. TAG is the tag of the
120 section for counters, BASE is offset of the counter position. */
123 tree_gen_one_value_profiler (struct histogram_value
*value ATTRIBUTE_UNUSED
,
124 unsigned tag ATTRIBUTE_UNUSED
,
125 unsigned base ATTRIBUTE_UNUSED
)
127 /* FIXME implement this. */
131 /* Output instructions as GIMPLE trees for code to find the most common value
132 of a difference between two evaluations of an expression.
133 VALUE is the expression whose value is profiled. TAG is the tag of the
134 section for counters, BASE is offset of the counter position. */
137 tree_gen_const_delta_profiler (struct histogram_value
*value ATTRIBUTE_UNUSED
,
138 unsigned tag ATTRIBUTE_UNUSED
,
139 unsigned base ATTRIBUTE_UNUSED
)
141 /* FIXME implement this. */
145 /* Return 1 if tree-based profiling is in effect, else 0.
146 If it is, set up hooks for tree-based profiling.
147 Gate for pass_tree_profile. */
149 static bool do_tree_profiling (void) {
150 if (flag_tree_based_profiling
)
152 tree_register_profile_hooks ();
153 tree_register_value_prof_hooks ();
155 return flag_tree_based_profiling
;
158 /* Return the file on which profile dump output goes, if any. */
160 static FILE *tree_profile_dump_file (void) {
164 struct tree_opt_pass pass_tree_profile
=
166 "tree_profile", /* name */
167 do_tree_profiling
, /* gate */
168 branch_prob
, /* execute */
171 0, /* static_pass_number */
172 TV_BRANCH_PROB
, /* tv_id */
173 PROP_gimple_leh
| PROP_cfg
, /* properties_required */
174 PROP_gimple_leh
| PROP_cfg
, /* properties_provided */
175 0, /* properties_destroyed */
176 0, /* todo_flags_start */
177 TODO_verify_stmts
/* todo_flags_finish */
180 struct profile_hooks tree_profile_hooks
=
182 tree_gen_edge_profiler
, /* gen_edge_profiler */
183 tree_gen_interval_profiler
, /* gen_interval_profiler */
184 tree_gen_pow2_profiler
, /* gen_pow2_profiler */
185 tree_gen_one_value_profiler
, /* gen_one_value_profiler */
186 tree_gen_const_delta_profiler
,/* gen_const_delta_profiler */
187 tree_profile_dump_file
/* profile_dump_file */