1/* Routines required for instrumenting a program. */
2/* Compile this one with gcc. */
3/* Copyright (C) 1989-2025 Free Software Foundation, Inc.
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
17Under Section 7 of GPL version 3, you are granted additional
18permissions described in the GCC Runtime Library Exception, version
193.1, as published by the Free Software Foundation.
20
21You should have received a copy of the GNU General Public License and
22a copy of the GCC Runtime Library Exception along with this program;
23see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24<http://www.gnu.org/licenses/>. */
25
26#include "libgcov.h"
27
28#if defined(inhibit_libc)
29/* If libc and its header files are not available, provide dummy functions. */
30
31#ifdef L_gcov_merge_add
32void __gcov_merge_add (gcov_type *counters __attribute__ ((unused)),
33 unsigned n_counters __attribute__ ((unused))) {}
34#endif
35
36#ifdef L_gcov_merge_ior
37void __gcov_merge_ior (gcov_type *counters __attribute__ ((unused)),
38 unsigned n_counters __attribute__ ((unused))) {}
39#endif
40
41#ifdef L_gcov_merge_topn
42void __gcov_merge_topn (gcov_type *counters __attribute__ ((unused)),
43 unsigned n_counters __attribute__ ((unused))) {}
44#endif
45
46#else
47
48#ifdef L_gcov_merge_add
49/* The profile merging function that just adds the counters. It is given
50 an array COUNTERS of N_COUNTERS old counters and it reads the same number
51 of counters from the gcov file. */
52void
53__gcov_merge_add (gcov_type *counters, unsigned n_counters)
54{
55 for (; n_counters; counters++, n_counters--)
56 *counters += gcov_get_counter ();
57}
58#endif /* L_gcov_merge_add */
59
60#ifdef L_gcov_merge_ior
61/* The profile merging function that just adds the counters. It is given
62 an array COUNTERS of N_COUNTERS old counters and it reads the same number
63 of counters from the gcov file. */
64void
65__gcov_merge_ior (gcov_type *counters, unsigned n_counters)
66{
67 for (; n_counters; counters++, n_counters--)
68 *counters |= gcov_get_counter_target ();
69}
70#endif
71
72#ifdef L_gcov_merge_time_profile
73/* Time profiles are merged so that minimum from all valid (greater than zero)
74 is stored. There could be a fork that creates new counters. To have
75 the profile stable, we chosen to pick the smallest function visit time. */
76void
77__gcov_merge_time_profile (gcov_type *counters, unsigned n_counters)
78{
79 unsigned int i;
80 gcov_type value;
81
82 for (i = 0; i < n_counters; i++)
83 {
84 value = gcov_get_counter_target ();
85
86 if (value && (!counters[i] || value < counters[i]))
87 counters[i] = value;
88 }
89}
90#endif /* L_gcov_merge_time_profile */
91
92#ifdef L_gcov_merge_topn
93
94/* The profile merging function for choosing the most common value.
95 It is given an array COUNTERS of N_COUNTERS old counters and it
96 reads the same number of counters from the gcov file. The counters
97 are split into pairs where the members of the tuple have
98 meanings:
99
100 -- the stored candidate on the most common value of the measured entity
101 -- counter
102
103 We use -TOTAL for situation when merging dropped some values.
104 The information is used for -fprofile-reproducible flag.
105 */
106
107void
108__gcov_merge_topn (gcov_type *counters, unsigned n_counters)
109{
110 gcc_assert (!(n_counters % GCOV_TOPN_MEM_COUNTERS));
111
112 for (unsigned i = 0; i < (n_counters / GCOV_TOPN_MEM_COUNTERS); i++)
113 {
114 /* First value is number of total executions of the profiler. */
115 gcov_type all = gcov_get_counter_ignore_scaling (ignore_scaling: -1);
116 gcov_type n = gcov_get_counter_ignore_scaling (ignore_scaling: -1);
117
118 unsigned full = all < 0;
119 gcov_type *total = &counters[GCOV_TOPN_MEM_COUNTERS * i];
120 *total += full ? -all : all;
121
122 for (unsigned j = 0; j < n; j++)
123 {
124 gcov_type value = gcov_get_counter_target ();
125 gcov_type count = gcov_get_counter_ignore_scaling (ignore_scaling: -1);
126
127 // TODO: we should use atomic here
128 full |= gcov_topn_add_value (counters: counters + GCOV_TOPN_MEM_COUNTERS * i,
129 value, count, use_atomic: 0, increment_total: 0);
130 }
131
132 if (full)
133 *total = -(*total);
134 }
135}
136#endif /* L_gcov_merge_topn */
137
138#endif /* inhibit_libc */
139

source code of libgcc/libgcov-merge.c