libgcc/libgcov-merge.c

   1 /* Routines required for instrumenting a program.  */
   2 /* Compile this one with gcc.  */
   3 /* Copyright (C) 1989-2021 Free Software Foundation, Inc.
   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
  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
  32 void __gcov_merge_add (gcov_type *counters  __attribute__ ((unused)),
  33                        unsigned n_counters __attribute__ ((unused))) {}
  34 #endif
  35
  36 #ifdef L_gcov_merge_topn
  37 void __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.  */
  47 void
  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.  */
  59 void
  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.  */
  71 void
  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 /* The profile merging function for choosing the most common value.
  90    It is given an array COUNTERS of N_COUNTERS old counters and it
  91    reads the same number of counters from the gcov file.  The counters
  92    are split into pairs where the members of the tuple have
  93    meanings:
  94
  95    -- the stored candidate on the most common value of the measured entity
  96    -- counter
  97
  98    We use -TOTAL for situation when merging dropped some values.
  99    The information is used for -fprofile-reproducible flag.
 100    */
 101
 102 void
 103 __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
 104 {
 105   gcc_assert (!(n_counters % GCOV_TOPN_MEM_COUNTERS));
 106
 107   for (unsigned i = 0; i < (n_counters / GCOV_TOPN_MEM_COUNTERS); i++)
 108     {
 109       /* First value is number of total executions of the profiler.  */
 110       gcov_type all = gcov_get_counter_ignore_scaling (-1);
 111       gcov_type n = gcov_get_counter_ignore_scaling (-1);
 112
 113       unsigned full = all < 0;
 114       gcov_type *total = &counters[GCOV_TOPN_MEM_COUNTERS * i];
 115       *total += full ? -all : all;
 116
 117       for (unsigned j = 0; j < n; j++)
 118         {
 119           gcov_type value = gcov_get_counter_target ();
 120           gcov_type count = gcov_get_counter_ignore_scaling (-1);
 121
 122           // TODO: we should use atomic here
 123           full |= gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i,
 124                                        value, count, 0, 0);
 125         }
 126
 127       if (full)
 128         *total = -(*total);
 129     }
 130 }
 131 #endif /* L_gcov_merge_topn */
 132
 133 #endif /* inhibit_libc */