Mercurial > hg > CbC > CbC_gcc
diff libgcc/libgcov-profiler.c @ 145:1830386684a0
gcc-9.2.0
author | anatofuz |
---|---|
date | Thu, 13 Feb 2020 11:34:05 +0900 |
parents | 84e7813d76e9 |
children |
line wrap: on
line diff
--- a/libgcc/libgcov-profiler.c Thu Oct 25 07:37:49 2018 +0900 +++ b/libgcc/libgcov-profiler.c Thu Feb 13 11:34:05 2020 +0900 @@ -1,6 +1,6 @@ /* Routines required for instrumenting a program. */ /* Compile this one with gcc. */ -/* Copyright (C) 1989-2018 Free Software Foundation, Inc. +/* Copyright (C) 1989-2020 Free Software Foundation, Inc. This file is part of GCC. @@ -106,46 +106,61 @@ #endif -/* Tries to determine the most common value among its inputs. Checks if the - value stored in COUNTERS[0] matches VALUE. If this is the case, COUNTERS[1] - is incremented. If this is not the case and COUNTERS[1] is not zero, - COUNTERS[1] is decremented. Otherwise COUNTERS[1] is set to one and - VALUE is stored to COUNTERS[0]. This algorithm guarantees that if this - function is called more than 50% of the time with one value, this value - will be in COUNTERS[0] in the end. - - In any case, COUNTERS[2] is incremented. If USE_ATOMIC is set to 1, - COUNTERS[2] is updated with an atomic instruction. */ +/* Tries to determine N most commons value among its inputs. */ static inline void -__gcov_one_value_profiler_body (gcov_type *counters, gcov_type value, - int use_atomic) +__gcov_topn_values_profiler_body (gcov_type *counters, gcov_type value, + int use_atomic) { - if (value == counters[0]) - counters[1]++; - else if (counters[1] == 0) + if (use_atomic) + __atomic_fetch_add (&counters[0], 1, __ATOMIC_RELAXED); + else + counters[0]++; + + ++counters; + + /* First try to find an existing value. */ + int empty_counter = -1; + + for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++) + if (value == counters[2 * i]) + { + if (use_atomic) + __atomic_fetch_add (&counters[2 * i + 1], GCOV_TOPN_VALUES, + __ATOMIC_RELAXED); + else + counters[2 * i + 1] += GCOV_TOPN_VALUES; + return; + } + else if (counters[2 * i + 1] <= 0) + empty_counter = i; + + /* Find an empty slot for a new value. */ + if (empty_counter != -1) { - counters[1] = 1; - counters[0] = value; + counters[2 * empty_counter] = value; + counters[2 * empty_counter + 1] = GCOV_TOPN_VALUES; + return; } - else - counters[1]--; - if (use_atomic) - __atomic_fetch_add (&counters[2], 1, __ATOMIC_RELAXED); - else - counters[2]++; + /* We haven't found an empty slot, then decrement all + counter values by one. */ + for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++) + if (use_atomic) + __atomic_fetch_sub (&counters[2 * i + 1], 1, __ATOMIC_RELAXED); + else + counters[2 * i + 1]--; } -#ifdef L_gcov_one_value_profiler +#ifdef L_gcov_topn_values_profiler void -__gcov_one_value_profiler (gcov_type *counters, gcov_type value) +__gcov_topn_values_profiler (gcov_type *counters, gcov_type value) { - __gcov_one_value_profiler_body (counters, value, 0); + __gcov_topn_values_profiler_body (counters, value, 0); } #endif -#if defined(L_gcov_one_value_profiler_atomic) && GCOV_SUPPORTS_ATOMIC +#if defined(L_gcov_topn_values_profiler_atomic) && GCOV_SUPPORTS_ATOMIC /* Update one value profilers (COUNTERS) for a given VALUE. @@ -157,146 +172,13 @@ https://gcc.gnu.org/ml/gcc-patches/2016-08/msg00024.html. */ void -__gcov_one_value_profiler_atomic (gcov_type *counters, gcov_type value) +__gcov_topn_values_profiler_atomic (gcov_type *counters, gcov_type value) { - __gcov_one_value_profiler_body (counters, value, 1); + __gcov_topn_values_profiler_body (counters, value, 1); } #endif -#ifdef L_gcov_indirect_call_topn_profiler -/* Tries to keep track the most frequent N values in the counters where - N is specified by parameter TOPN_VAL. To track top N values, 2*N counter - entries are used. - counter[0] --- the accumative count of the number of times one entry in - in the counters gets evicted/replaced due to limited capacity. - When this value reaches a threshold, the bottom N values are - cleared. - counter[1] through counter[2*N] records the top 2*N values collected so far. - Each value is represented by two entries: count[2*i+1] is the ith value, and - count[2*i+2] is the number of times the value is seen. */ - -static void -__gcov_topn_value_profiler_body (gcov_type *counters, gcov_type value) -{ - unsigned i, found = 0, have_zero_count = 0; - gcov_type *entry; - gcov_type *lfu_entry = &counters[1]; - gcov_type *value_array = &counters[1]; - gcov_type *num_eviction = &counters[0]; - gcov_unsigned_t topn_val = GCOV_ICALL_TOPN_VAL; - - /* There are 2*topn_val values tracked, each value takes two slots in the - counter array. */ - for (i = 0; i < (topn_val << 2); i += 2) - { - entry = &value_array[i]; - if (entry[0] == value) - { - entry[1]++ ; - found = 1; - break; - } - else if (entry[1] == 0) - { - lfu_entry = entry; - have_zero_count = 1; - } - else if (entry[1] < lfu_entry[1]) - lfu_entry = entry; - } - - if (found) - return; - - /* lfu_entry is either an empty entry or an entry - with lowest count, which will be evicted. */ - lfu_entry[0] = value; - lfu_entry[1] = 1; - -#define GCOV_ICALL_COUNTER_CLEAR_THRESHOLD 3000 - - /* Too many evictions -- time to clear bottom entries to - avoid hot values bumping each other out. */ - if (!have_zero_count - && ++*num_eviction >= GCOV_ICALL_COUNTER_CLEAR_THRESHOLD) - { - unsigned i, j; - gcov_type *p, minv; - gcov_type* tmp_cnts - = (gcov_type *)alloca (topn_val * sizeof (gcov_type)); - - *num_eviction = 0; - - for (i = 0; i < topn_val; i++) - tmp_cnts[i] = 0; - - /* Find the largest topn_val values from the group of - 2*topn_val values and put them into tmp_cnts. */ - - for (i = 0; i < 2 * topn_val; i += 2) - { - p = 0; - for (j = 0; j < topn_val; j++) - { - if (!p || tmp_cnts[j] < *p) - p = &tmp_cnts[j]; - } - if (value_array[i + 1] > *p) - *p = value_array[i + 1]; - } - - minv = tmp_cnts[0]; - for (j = 1; j < topn_val; j++) - { - if (tmp_cnts[j] < minv) - minv = tmp_cnts[j]; - } - /* Zero out low value entries. */ - for (i = 0; i < 2 * topn_val; i += 2) - { - if (value_array[i + 1] < minv) - { - value_array[i] = 0; - value_array[i + 1] = 0; - } - } - } -} - -/* These two variables are used to actually track caller and callee. Keep - them in TLS memory so races are not common (they are written to often). - The variables are set directly by GCC instrumented code, so declaration - here must match one in tree-profile.c. */ - -#if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS) -__thread -#endif -struct indirect_call_tuple __gcov_indirect_call_topn; - -#ifdef TARGET_VTABLE_USES_DESCRIPTORS -#define VTABLE_USES_DESCRIPTORS 1 -#else -#define VTABLE_USES_DESCRIPTORS 0 -#endif - -/* This fucntion is instrumented at function entry to track topn indirect - calls to CUR_FUNC. */ - -void -__gcov_indirect_call_topn_profiler (gcov_type value, void* cur_func) -{ - void *callee_func = __gcov_indirect_call_topn.callee; - /* If the C++ virtual tables contain function descriptors then one - function may have multiple descriptors and we need to dereference - the descriptors to see if they point to the same function. */ - if (cur_func == callee_func - || (VTABLE_USES_DESCRIPTORS && callee_func - && *(void **) cur_func == *(void **) callee_func)) - __gcov_topn_value_profiler_body (__gcov_indirect_call_topn.counters, value); -} -#endif - -#ifdef L_gcov_indirect_call_profiler_v2 +#ifdef L_gcov_indirect_call_profiler_v4 /* These two variables are used to actually track caller and callee. Keep them in TLS memory so races are not common (they are written to often). @@ -317,8 +199,9 @@ as a pointer to a function. */ /* Tries to determine the most common value among its inputs. */ -void -__gcov_indirect_call_profiler_v2 (gcov_type value, void* cur_func) +static inline void +__gcov_indirect_call_profiler_body (gcov_type value, void *cur_func, + int use_atomic) { /* If the C++ virtual tables contain function descriptors then one function may have multiple descriptors and we need to dereference @@ -326,16 +209,32 @@ if (cur_func == __gcov_indirect_call.callee || (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && *(void **) cur_func == *(void **) __gcov_indirect_call.callee)) - __gcov_one_value_profiler_body (__gcov_indirect_call.counters, value, 0); + __gcov_topn_values_profiler_body (__gcov_indirect_call.counters, value, + use_atomic); __gcov_indirect_call.callee = NULL; } + +void +__gcov_indirect_call_profiler_v4 (gcov_type value, void *cur_func) +{ + __gcov_indirect_call_profiler_body (value, cur_func, 0); +} + +#if GCOV_SUPPORTS_ATOMIC +void +__gcov_indirect_call_profiler_v4_atomic (gcov_type value, void *cur_func) +{ + __gcov_indirect_call_profiler_body (value, cur_func, 1); +} +#endif + #endif #ifdef L_gcov_time_profiler /* Counter for first visit of each function. */ -gcov_type __gcov_time_profiler_counter ATTRIBUTE_HIDDEN = 1; +gcov_type __gcov_time_profiler_counter ATTRIBUTE_HIDDEN; #endif