1/* Routines required for instrumenting a program.  */
2/* Compile this one with gcc.  */
3/* Copyright (C) 1989-2022 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#if !defined(inhibit_libc)
28
29#ifdef L_gcov_interval_profiler
30/* If VALUE is in interval <START, START + STEPS - 1>, then increases the
31   corresponding counter in COUNTERS.  If the VALUE is above or below
32   the interval, COUNTERS[STEPS] or COUNTERS[STEPS + 1] is increased
33   instead.  */
34
35void
36__gcov_interval_profiler (gcov_type *counters, gcov_type value,
37                          int start, unsigned steps)
38{
39  gcov_type delta = value - start;
40  if (delta < 0)
41    counters[steps + 1]++;
42  else if (delta >= steps)
43    counters[steps]++;
44  else
45    counters[delta]++;
46}
47#endif
48
49#if defined(L_gcov_interval_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
50/* If VALUE is in interval <START, START + STEPS - 1>, then increases the
51   corresponding counter in COUNTERS.  If the VALUE is above or below
52   the interval, COUNTERS[STEPS] or COUNTERS[STEPS + 1] is increased
53   instead.  Function is thread-safe.  */
54
55void
56__gcov_interval_profiler_atomic (gcov_type *counters, gcov_type value,
57				 int start, unsigned steps)
58{
59  gcov_type delta = value - start;
60  if (delta < 0)
61    __atomic_fetch_add (&counters[steps + 1], 1, __ATOMIC_RELAXED);
62  else if (delta >= steps)
63    __atomic_fetch_add (&counters[steps], 1, __ATOMIC_RELAXED);
64  else
65    __atomic_fetch_add (&counters[delta], 1, __ATOMIC_RELAXED);
66}
67#endif
68
69#ifdef L_gcov_pow2_profiler
70/* If VALUE is a power of two, COUNTERS[1] is incremented.  Otherwise
71   COUNTERS[0] is incremented.  */
72
73void
74__gcov_pow2_profiler (gcov_type *counters, gcov_type value)
75{
76  if (value == 0 || (value & (value - 1)))
77    counters[0]++;
78  else
79    counters[1]++;
80}
81#endif
82
83#if defined(L_gcov_pow2_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
84/* If VALUE is a power of two, COUNTERS[1] is incremented.  Otherwise
85   COUNTERS[0] is incremented.  Function is thread-safe.  */
86
87void
88__gcov_pow2_profiler_atomic (gcov_type *counters, gcov_type value)
89{
90  if (value == 0 || (value & (value - 1)))
91    __atomic_fetch_add (&counters[0], 1, __ATOMIC_RELAXED);
92  else
93    __atomic_fetch_add (&counters[1], 1, __ATOMIC_RELAXED);
94}
95#endif
96
97/* Tries to determine N most commons value among its inputs.  */
98
99static inline void
100__gcov_topn_values_profiler_body (gcov_type *counters, gcov_type value,
101				  int use_atomic)
102{
103  gcov_topn_add_value (counters, value, 1, use_atomic, 1);
104}
105
106#ifdef L_gcov_topn_values_profiler
107void
108__gcov_topn_values_profiler (gcov_type *counters, gcov_type value)
109{
110  __gcov_topn_values_profiler_body (counters, value, 0);
111}
112#endif
113
114#if defined(L_gcov_topn_values_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
115
116/* Update one value profilers (COUNTERS) for a given VALUE.
117
118   CAVEAT: Following function is not thread-safe, only total number
119   of executions (COUNTERS[2]) is update with an atomic instruction.
120   Problem is that one cannot atomically update two counters
121   (COUNTERS[0] and COUNTERS[1]), for more information please read
122   following email thread:
123   https://gcc.gnu.org/ml/gcc-patches/2016-08/msg00024.html.  */
124
125void
126__gcov_topn_values_profiler_atomic (gcov_type *counters, gcov_type value)
127{
128  __gcov_topn_values_profiler_body (counters, value, 1);
129}
130#endif
131
132#ifdef L_gcov_indirect_call_profiler_v4
133
134/* These two variables are used to actually track caller and callee.  Keep
135   them in TLS memory so races are not common (they are written to often).
136   The variables are set directly by GCC instrumented code, so declaration
137   here must match one in tree-profile.c  */
138
139#if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS)
140__thread
141#endif
142struct indirect_call_tuple __gcov_indirect_call;
143
144/* By default, the C++ compiler will use function addresses in the
145   vtable entries.  Setting TARGET_VTABLE_USES_DESCRIPTORS to nonzero
146   tells the compiler to use function descriptors instead.  The value
147   of this macro says how many words wide the descriptor is (normally 2).
148
149   It is assumed that the address of a function descriptor may be treated
150   as a pointer to a function.  */
151
152/* Tries to determine the most common value among its inputs. */
153static inline void
154__gcov_indirect_call_profiler_body (gcov_type value, void *cur_func,
155				    int use_atomic)
156{
157  /* If the C++ virtual tables contain function descriptors then one
158     function may have multiple descriptors and we need to dereference
159     the descriptors to see if they point to the same function.  */
160  if (cur_func == __gcov_indirect_call.callee
161      || (__LIBGCC_VTABLE_USES_DESCRIPTORS__
162	  && *(void **) cur_func == *(void **) __gcov_indirect_call.callee))
163    __gcov_topn_values_profiler_body (__gcov_indirect_call.counters, value,
164				      use_atomic);
165
166  __gcov_indirect_call.callee = NULL;
167}
168
169void
170__gcov_indirect_call_profiler_v4 (gcov_type value, void *cur_func)
171{
172  __gcov_indirect_call_profiler_body (value, cur_func, 0);
173}
174
175#if GCOV_SUPPORTS_ATOMIC
176void
177__gcov_indirect_call_profiler_v4_atomic (gcov_type value, void *cur_func)
178{
179  __gcov_indirect_call_profiler_body (value, cur_func, 1);
180}
181#endif
182
183#endif
184
185#ifdef L_gcov_time_profiler
186
187/* Counter for first visit of each function.  */
188gcov_type __gcov_time_profiler_counter ATTRIBUTE_HIDDEN;
189
190#endif
191
192#ifdef L_gcov_average_profiler
193/* Increase corresponding COUNTER by VALUE.  FIXME: Perhaps we want
194   to saturate up.  */
195
196void
197__gcov_average_profiler (gcov_type *counters, gcov_type value)
198{
199  counters[0] += value;
200  counters[1] ++;
201}
202#endif
203
204#if defined(L_gcov_average_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
205/* Increase corresponding COUNTER by VALUE.  FIXME: Perhaps we want
206   to saturate up.  Function is thread-safe.  */
207
208void
209__gcov_average_profiler_atomic (gcov_type *counters, gcov_type value)
210{
211  __atomic_fetch_add (&counters[0], value, __ATOMIC_RELAXED);
212  __atomic_fetch_add (&counters[1], 1, __ATOMIC_RELAXED);
213}
214#endif
215
216#ifdef L_gcov_ior_profiler
217/* Bitwise-OR VALUE into COUNTER.  */
218
219void
220__gcov_ior_profiler (gcov_type *counters, gcov_type value)
221{
222  *counters |= value;
223}
224#endif
225
226#if defined(L_gcov_ior_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
227/* Bitwise-OR VALUE into COUNTER.  Function is thread-safe.  */
228
229void
230__gcov_ior_profiler_atomic (gcov_type *counters, gcov_type value)
231{
232  __atomic_fetch_or (&counters[0], value, __ATOMIC_RELAXED);
233}
234#endif
235
236
237#endif /* inhibit_libc */
238