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ded3d3f8 | 1 | /* Routines required for instrumenting a program. */ |
2 | /* Compile this one with gcc. */ | |
f9fb6ba0 | 3 | /* Copyright (C) 1989-2014 Free Software Foundation, Inc. |
ded3d3f8 | 4 | |
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 3, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | Under Section 7 of GPL version 3, you are granted additional | |
18 | permissions described in the GCC Runtime Library Exception, version | |
19 | 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | You should have received a copy of the GNU General Public License and | |
22 | a copy of the GCC Runtime Library Exception along with this program; | |
23 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | <http://www.gnu.org/licenses/>. */ | |
25 | ||
67745126 | 26 | #include "libgcov.h" |
ded3d3f8 | 27 | #if !defined(inhibit_libc) |
ded3d3f8 | 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 | ||
35 | void | |
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 | #ifdef L_gcov_pow2_profiler | |
50 | /* If VALUE is a power of two, COUNTERS[1] is incremented. Otherwise | |
51 | COUNTERS[0] is incremented. */ | |
52 | ||
53 | void | |
54 | __gcov_pow2_profiler (gcov_type *counters, gcov_type value) | |
55 | { | |
56 | if (value & (value - 1)) | |
57 | counters[0]++; | |
58 | else | |
59 | counters[1]++; | |
60 | } | |
61 | #endif | |
62 | ||
63 | /* Tries to determine the most common value among its inputs. Checks if the | |
64 | value stored in COUNTERS[0] matches VALUE. If this is the case, COUNTERS[1] | |
65 | is incremented. If this is not the case and COUNTERS[1] is not zero, | |
66 | COUNTERS[1] is decremented. Otherwise COUNTERS[1] is set to one and | |
67 | VALUE is stored to COUNTERS[0]. This algorithm guarantees that if this | |
68 | function is called more than 50% of the time with one value, this value | |
69 | will be in COUNTERS[0] in the end. | |
70 | ||
71 | In any case, COUNTERS[2] is incremented. */ | |
72 | ||
73 | static inline void | |
74 | __gcov_one_value_profiler_body (gcov_type *counters, gcov_type value) | |
75 | { | |
76 | if (value == counters[0]) | |
77 | counters[1]++; | |
78 | else if (counters[1] == 0) | |
79 | { | |
80 | counters[1] = 1; | |
81 | counters[0] = value; | |
82 | } | |
83 | else | |
84 | counters[1]--; | |
85 | counters[2]++; | |
86 | } | |
87 | ||
88 | #ifdef L_gcov_one_value_profiler | |
89 | void | |
90 | __gcov_one_value_profiler (gcov_type *counters, gcov_type value) | |
91 | { | |
92 | __gcov_one_value_profiler_body (counters, value); | |
93 | } | |
94 | #endif | |
95 | ||
8ceaa1ef | 96 | #ifdef L_gcov_indirect_call_topn_profiler |
97 | /* Tries to keep track the most frequent N values in the counters where | |
98 | N is specified by parameter TOPN_VAL. To track top N values, 2*N counter | |
99 | entries are used. | |
100 | counter[0] --- the accumative count of the number of times one entry in | |
101 | in the counters gets evicted/replaced due to limited capacity. | |
102 | When this value reaches a threshold, the bottom N values are | |
103 | cleared. | |
104 | counter[1] through counter[2*N] records the top 2*N values collected so far. | |
105 | Each value is represented by two entries: count[2*i+1] is the ith value, and | |
106 | count[2*i+2] is the number of times the value is seen. */ | |
107 | ||
108 | static void | |
109 | __gcov_topn_value_profiler_body (gcov_type *counters, gcov_type value) | |
110 | { | |
111 | unsigned i, found = 0, have_zero_count = 0; | |
112 | gcov_type *entry; | |
113 | gcov_type *lfu_entry = &counters[1]; | |
114 | gcov_type *value_array = &counters[1]; | |
115 | gcov_type *num_eviction = &counters[0]; | |
116 | gcov_unsigned_t topn_val = GCOV_ICALL_TOPN_VAL; | |
117 | ||
118 | /* There are 2*topn_val values tracked, each value takes two slots in the | |
119 | counter array. */ | |
120 | for (i = 0; i < (topn_val << 2); i += 2) | |
121 | { | |
122 | entry = &value_array[i]; | |
123 | if (entry[0] == value) | |
124 | { | |
125 | entry[1]++ ; | |
126 | found = 1; | |
127 | break; | |
128 | } | |
129 | else if (entry[1] == 0) | |
130 | { | |
131 | lfu_entry = entry; | |
132 | have_zero_count = 1; | |
133 | } | |
134 | else if (entry[1] < lfu_entry[1]) | |
135 | lfu_entry = entry; | |
136 | } | |
137 | ||
138 | if (found) | |
139 | return; | |
140 | ||
141 | /* lfu_entry is either an empty entry or an entry | |
142 | with lowest count, which will be evicted. */ | |
143 | lfu_entry[0] = value; | |
144 | lfu_entry[1] = 1; | |
145 | ||
146 | #define GCOV_ICALL_COUNTER_CLEAR_THRESHOLD 3000 | |
147 | ||
148 | /* Too many evictions -- time to clear bottom entries to | |
149 | avoid hot values bumping each other out. */ | |
150 | if (!have_zero_count | |
151 | && ++*num_eviction >= GCOV_ICALL_COUNTER_CLEAR_THRESHOLD) | |
152 | { | |
153 | unsigned i, j; | |
154 | gcov_type *p, minv; | |
155 | gcov_type* tmp_cnts | |
156 | = (gcov_type *)alloca (topn_val * sizeof (gcov_type)); | |
157 | ||
158 | *num_eviction = 0; | |
159 | ||
160 | for (i = 0; i < topn_val; i++) | |
161 | tmp_cnts[i] = 0; | |
162 | ||
163 | /* Find the largest topn_val values from the group of | |
164 | 2*topn_val values and put them into tmp_cnts. */ | |
165 | ||
166 | for (i = 0; i < 2 * topn_val; i += 2) | |
167 | { | |
168 | p = 0; | |
169 | for (j = 0; j < topn_val; j++) | |
170 | { | |
171 | if (!p || tmp_cnts[j] < *p) | |
172 | p = &tmp_cnts[j]; | |
173 | } | |
174 | if (value_array[i + 1] > *p) | |
175 | *p = value_array[i + 1]; | |
176 | } | |
177 | ||
178 | minv = tmp_cnts[0]; | |
179 | for (j = 1; j < topn_val; j++) | |
180 | { | |
181 | if (tmp_cnts[j] < minv) | |
182 | minv = tmp_cnts[j]; | |
183 | } | |
184 | /* Zero out low value entries. */ | |
185 | for (i = 0; i < 2 * topn_val; i += 2) | |
186 | { | |
187 | if (value_array[i + 1] < minv) | |
188 | { | |
189 | value_array[i] = 0; | |
190 | value_array[i + 1] = 0; | |
191 | } | |
192 | } | |
193 | } | |
194 | } | |
195 | ||
196 | /* These two variables are used to actually track caller and callee. Keep | |
197 | them in TLS memory so races are not common (they are written to often). | |
198 | The variables are set directly by GCC instrumented code, so declaration | |
199 | here must match one in tree-profile.c. */ | |
200 | ||
201 | #if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS) | |
202 | __thread | |
203 | #endif | |
204 | gcov_type *__gcov_indirect_call_topn_counters ATTRIBUTE_HIDDEN; | |
205 | ||
206 | #if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS) | |
207 | __thread | |
208 | #endif | |
209 | void *__gcov_indirect_call_topn_callee ATTRIBUTE_HIDDEN; | |
210 | ||
211 | #ifdef TARGET_VTABLE_USES_DESCRIPTORS | |
212 | #define VTABLE_USES_DESCRIPTORS 1 | |
213 | #else | |
214 | #define VTABLE_USES_DESCRIPTORS 0 | |
215 | #endif | |
216 | ||
217 | /* This fucntion is instrumented at function entry to track topn indirect | |
218 | calls to CUR_FUNC. */ | |
219 | ||
220 | void | |
221 | __gcov_indirect_call_topn_profiler (gcov_type value, void* cur_func) | |
222 | { | |
223 | void *callee_func = __gcov_indirect_call_topn_callee; | |
224 | /* If the C++ virtual tables contain function descriptors then one | |
225 | function may have multiple descriptors and we need to dereference | |
226 | the descriptors to see if they point to the same function. */ | |
227 | if (cur_func == callee_func | |
228 | || (VTABLE_USES_DESCRIPTORS && callee_func | |
229 | && *(void **) cur_func == *(void **) callee_func)) | |
230 | __gcov_topn_value_profiler_body (__gcov_indirect_call_topn_counters, value); | |
231 | } | |
232 | #endif | |
233 | ||
ded3d3f8 | 234 | #ifdef L_gcov_indirect_call_profiler |
235 | /* This function exist only for workaround of binutils bug 14342. | |
236 | Once this compatibility hack is obsolette, it can be removed. */ | |
237 | ||
238 | /* By default, the C++ compiler will use function addresses in the | |
239 | vtable entries. Setting TARGET_VTABLE_USES_DESCRIPTORS to nonzero | |
240 | tells the compiler to use function descriptors instead. The value | |
325b8c3c | 241 | of this macro says how many words wide the descriptor is (normally 2). |
ded3d3f8 | 242 | |
243 | It is assumed that the address of a function descriptor may be treated | |
244 | as a pointer to a function. */ | |
245 | ||
ded3d3f8 | 246 | /* Tries to determine the most common value among its inputs. */ |
247 | void | |
248 | __gcov_indirect_call_profiler (gcov_type* counter, gcov_type value, | |
249 | void* cur_func, void* callee_func) | |
250 | { | |
251 | /* If the C++ virtual tables contain function descriptors then one | |
252 | function may have multiple descriptors and we need to dereference | |
253 | the descriptors to see if they point to the same function. */ | |
254 | if (cur_func == callee_func | |
325b8c3c | 255 | || (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && callee_func |
ded3d3f8 | 256 | && *(void **) cur_func == *(void **) callee_func)) |
257 | __gcov_one_value_profiler_body (counter, value); | |
258 | } | |
ded3d3f8 | 259 | #endif |
8ceaa1ef | 260 | |
ded3d3f8 | 261 | #ifdef L_gcov_indirect_call_profiler_v2 |
262 | ||
263 | /* These two variables are used to actually track caller and callee. Keep | |
264 | them in TLS memory so races are not common (they are written to often). | |
265 | The variables are set directly by GCC instrumented code, so declaration | |
266 | here must match one in tree-profile.c */ | |
267 | ||
268 | #if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS) | |
269 | __thread | |
270 | #endif | |
271 | void * __gcov_indirect_call_callee; | |
272 | #if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS) | |
273 | __thread | |
274 | #endif | |
275 | gcov_type * __gcov_indirect_call_counters; | |
276 | ||
277 | /* By default, the C++ compiler will use function addresses in the | |
278 | vtable entries. Setting TARGET_VTABLE_USES_DESCRIPTORS to nonzero | |
279 | tells the compiler to use function descriptors instead. The value | |
325b8c3c | 280 | of this macro says how many words wide the descriptor is (normally 2). |
ded3d3f8 | 281 | |
282 | It is assumed that the address of a function descriptor may be treated | |
283 | as a pointer to a function. */ | |
284 | ||
ded3d3f8 | 285 | /* Tries to determine the most common value among its inputs. */ |
286 | void | |
287 | __gcov_indirect_call_profiler_v2 (gcov_type value, void* cur_func) | |
288 | { | |
289 | /* If the C++ virtual tables contain function descriptors then one | |
290 | function may have multiple descriptors and we need to dereference | |
291 | the descriptors to see if they point to the same function. */ | |
292 | if (cur_func == __gcov_indirect_call_callee | |
325b8c3c | 293 | || (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && __gcov_indirect_call_callee |
ded3d3f8 | 294 | && *(void **) cur_func == *(void **) __gcov_indirect_call_callee)) |
295 | __gcov_one_value_profiler_body (__gcov_indirect_call_counters, value); | |
296 | } | |
297 | #endif | |
298 | ||
299 | #ifdef L_gcov_time_profiler | |
300 | ||
301 | /* Counter for first visit of each function. */ | |
302 | static gcov_type function_counter; | |
303 | ||
304 | /* Sets corresponding COUNTERS if there is no value. */ | |
305 | ||
306 | void | |
307 | __gcov_time_profiler (gcov_type* counters) | |
308 | { | |
309 | if (!counters[0]) | |
310 | counters[0] = ++function_counter; | |
311 | } | |
312 | #endif | |
313 | ||
314 | #ifdef L_gcov_average_profiler | |
315 | /* Increase corresponding COUNTER by VALUE. FIXME: Perhaps we want | |
316 | to saturate up. */ | |
317 | ||
318 | void | |
319 | __gcov_average_profiler (gcov_type *counters, gcov_type value) | |
320 | { | |
321 | counters[0] += value; | |
322 | counters[1] ++; | |
323 | } | |
324 | #endif | |
325 | ||
326 | #ifdef L_gcov_ior_profiler | |
327 | /* Bitwise-OR VALUE into COUNTER. */ | |
328 | ||
329 | void | |
330 | __gcov_ior_profiler (gcov_type *counters, gcov_type value) | |
331 | { | |
332 | *counters |= value; | |
333 | } | |
334 | #endif | |
335 | ||
336 | #endif /* inhibit_libc */ |