libgcc/libgcov-merge.c

   1 /* Routines required for instrumenting a program.  */
   2 /* Compile this one with gcc.  */
   3 /* Copyright (C) 1989-2019 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 static void
  90 merge_topn_values_set (gcov_type *counters)
  91 {
  92   /* First value is number of total executions of the profiler.  */
  93   gcov_type all = gcov_get_counter_ignore_scaling (-1);
  94   counters[0] += all;
  95   ++counters;
  96
  97   /* Read all part values.  */
  98   gcov_type read_counters[2 * GCOV_TOPN_VALUES];
  99
 100   for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
 101     {
 102       read_counters[2 * i] = gcov_get_counter_target ();
 103       read_counters[2 * i + 1] = gcov_get_counter_ignore_scaling (-1);
 104     }
 105
 106   if (read_counters[1] == -1)
 107     {
 108       counters[1] = -1;
 109       return;
 110     }
 111
 112   for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
 113     {
 114       if (read_counters[2 * i + 1] == 0)
 115         return;
 116
 117       unsigned j;
 118       for (j = 0; j < GCOV_TOPN_VALUES; j++)
 119         {
 120           if (counters[2 * j] == read_counters[2 * i])
 121             {
 122               counters[2 * j + 1] += read_counters[2 * i + 1];
 123               break;
 124             }
 125           else if (counters[2 * j + 1] == 0)
 126             {
 127               counters[2 * j] += read_counters[2 * i];
 128               counters[2 * j + 1] += read_counters[2 * i + 1];
 129               break;
 130             }
 131         }
 132
 133       /* We haven't found a slot, bail out.  */
 134       if (j == GCOV_TOPN_VALUES)
 135         {
 136           counters[1] = -1;
 137           return;
 138         }
 139     }
 140 }
 141
 142 /* The profile merging function for choosing the most common value.
 143    It is given an array COUNTERS of N_COUNTERS old counters and it
 144    reads the same number of counters from the gcov file.  The counters
 145    are split into pairs where the members of the tuple have
 146    meanings:
 147
 148    -- the stored candidate on the most common value of the measured entity
 149    -- counter
 150    */
 151 void
 152 __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
 153 {
 154   gcc_assert (!(n_counters % GCOV_TOPN_VALUES_COUNTERS));
 155
 156   for (unsigned i = 0; i < (n_counters / GCOV_TOPN_VALUES_COUNTERS); i++)
 157     merge_topn_values_set (counters + (i * GCOV_TOPN_VALUES_COUNTERS));
 158 }
 159 #endif /* L_gcov_merge_topn */
 160
 161 #endif /* inhibit_libc */