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_single
  37 void __gcov_merge_single (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_single
  88
  89 static void
  90 merge_single_value_set (gcov_type *counters)
  91 {
  92   unsigned j;
  93   gcov_type value, counter;
  94
  95   /* First value is number of total executions of the profiler.  */
  96   gcov_type all = gcov_get_counter_ignore_scaling (-1);
  97   counters[0] += all;
  98   ++counters;
  99
 100   for (unsigned i = 0; i < GCOV_DISK_SINGLE_VALUES; i++)
 101     {
 102       value = gcov_get_counter_target ();
 103       counter = gcov_get_counter_ignore_scaling (-1);
 104
 105       if (counter == -1)
 106         {
 107           counters[1] = -1;
 108           /* We can't return as we need to read all counters.  */
 109           continue;
 110         }
 111       else if (counter == 0 || counters[1] == -1)
 112         {
 113           /* We can't return as we need to read all counters.  */
 114           continue;
 115         }
 116
 117       for (j = 0; j < GCOV_DISK_SINGLE_VALUES; j++)
 118         {
 119           if (counters[2 * j] == value)
 120             {
 121               counters[2 * j + 1] += counter;
 122               break;
 123             }
 124           else if (counters[2 * j + 1] == 0)
 125             {
 126               counters[2 * j] = value;
 127               counters[2 * j + 1] = counter;
 128               break;
 129             }
 130         }
 131
 132       /* We haven't found a free slot for the value, mark overflow.  */
 133       if (j == GCOV_DISK_SINGLE_VALUES)
 134         counters[1] = -1;
 135     }
 136 }
 137
 138 /* The profile merging function for choosing the most common value.
 139    It is given an array COUNTERS of N_COUNTERS old counters and it
 140    reads the same number of counters from the gcov file.  The counters
 141    are split into pairs where the members of the tuple have
 142    meanings:
 143
 144    -- the stored candidate on the most common value of the measured entity
 145    -- counter
 146    */
 147 void
 148 __gcov_merge_single (gcov_type *counters, unsigned n_counters)
 149 {
 150   gcc_assert (!(n_counters % GCOV_SINGLE_VALUE_COUNTERS));
 151
 152   for (unsigned i = 0; i < (n_counters / GCOV_SINGLE_VALUE_COUNTERS); i++)
 153     merge_single_value_set (counters + (i * GCOV_SINGLE_VALUE_COUNTERS));
 154 }
 155 #endif /* L_gcov_merge_single */
 156
 157 #endif /* inhibit_libc */