1/* Routines required for instrumenting a program.  */
2/* Compile this one with gcc.  */
3/* Copyright (C) 1989-2020 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_topn
37void __gcov_merge_topn (gcov_type *counters  __attribute__ ((unused)),
38			unsigned n_counters __attribute__ ((unused))) {}
39#endif
40
41#else
42
43#ifdef L_gcov_merge_add
44/* The profile merging function that just adds the counters.  It is given
45   an array COUNTERS of N_COUNTERS old counters and it reads the same number
46   of counters from the gcov file.  */
47void
48__gcov_merge_add (gcov_type *counters, unsigned n_counters)
49{
50  for (; n_counters; counters++, n_counters--)
51    *counters += gcov_get_counter ();
52}
53#endif /* L_gcov_merge_add */
54
55#ifdef L_gcov_merge_ior
56/* The profile merging function that just adds the counters.  It is given
57   an array COUNTERS of N_COUNTERS old counters and it reads the same number
58   of counters from the gcov file.  */
59void
60__gcov_merge_ior (gcov_type *counters, unsigned n_counters)
61{
62  for (; n_counters; counters++, n_counters--)
63    *counters |= gcov_get_counter_target ();
64}
65#endif
66
67#ifdef L_gcov_merge_time_profile
68/* Time profiles are merged so that minimum from all valid (greater than zero)
69   is stored. There could be a fork that creates new counters. To have
70   the profile stable, we chosen to pick the smallest function visit time.  */
71void
72__gcov_merge_time_profile (gcov_type *counters, unsigned n_counters)
73{
74  unsigned int i;
75  gcov_type value;
76
77  for (i = 0; i < n_counters; i++)
78    {
79      value = gcov_get_counter_target ();
80
81      if (value && (!counters[i] || value < counters[i]))
82        counters[i] = value;
83    }
84}
85#endif /* L_gcov_merge_time_profile */
86
87#ifdef L_gcov_merge_topn
88
89/* To merging of TOPN profiles.
90   counters[0] is the number of executions
91   for i in 0 ... TOPN-1
92     counters[2 * i + 1] is target
93     counters[2 * i + 2] is corresponding hitrate counter.
94
95   Because we prune counters only those with probability >= 1/TOPN are
96   present now.
97
98   We use sign of counters[0] to track whether the number of different
99   targets exceeds TOPN.  */
100
101static void
102merge_topn_values_set (gcov_type *counters)
103{
104  /* First value is number of total executions of the profiler.  */
105  gcov_type all = gcov_get_counter ();
106  gcov_type *total = &counters[0];
107  ++counters;
108
109  /* Negative value means that counter is missing some of values.  */
110  if (all < 0)
111    *total = -(*total);
112
113  *total += all;
114
115  /* Read all part values.  */
116  gcov_type read_counters[2 * GCOV_TOPN_VALUES];
117  for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
118    {
119      read_counters[2 * i] = gcov_get_counter_target ();
120      read_counters[2 * i + 1] = gcov_get_counter_ignore_scaling (-1);
121    }
122
123  for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
124    {
125      if (read_counters[2 * i + 1] == 0)
126	continue;
127
128      unsigned j;
129      int slot = 0;
130
131      for (j = 0; j < GCOV_TOPN_VALUES; j++)
132	{
133	  if (counters[2 * j] == read_counters[2 * i])
134	    {
135	      counters[2 * j + 1] += read_counters[2 * i + 1];
136	      break;
137	    }
138	  else if (counters[2 * j + 1] < counters[2 * slot + 1])
139	    slot = j;
140	}
141
142      if (j == GCOV_TOPN_VALUES)
143	{
144	  gcov_type slot_count = counters[2 * slot + 1];
145	  /* We found an empty slot.  */
146	  if (slot_count == 0)
147	    {
148	      /* If we found empty slot, add the value.  */
149	      counters[2 * slot] = read_counters[2 * i];
150	      counters[2 * slot + 1] = read_counters[2 * i + 1];
151	    }
152	  else
153	    {
154	      /* Here we are loosing some values.  */
155	      if (*total >= 0)
156		*total = -(*total);
157	      if (read_counters[2 * i + 1] > slot_count)
158		{
159		  counters[2 * slot] = read_counters[2 * i];
160		  counters[2 * slot + 1] = read_counters[2 * i + 1];
161		}
162	      else
163		counters[2 * slot + 1] -= read_counters[2 * i + 1];
164	    }
165	}
166    }
167}
168
169/* The profile merging function for choosing the most common value.
170   It is given an array COUNTERS of N_COUNTERS old counters and it
171   reads the same number of counters from the gcov file.  The counters
172   are split into pairs where the members of the tuple have
173   meanings:
174
175   -- the stored candidate on the most common value of the measured entity
176   -- counter
177   */
178void
179__gcov_merge_topn (gcov_type *counters, unsigned n_counters)
180{
181  gcc_assert (!(n_counters % GCOV_TOPN_VALUES_COUNTERS));
182
183  for (unsigned i = 0; i < (n_counters / GCOV_TOPN_VALUES_COUNTERS); i++)
184    merge_topn_values_set (counters + (i * GCOV_TOPN_VALUES_COUNTERS));
185}
186#endif /* L_gcov_merge_topn */
187
188#endif /* inhibit_libc */
189