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 {
  39 }
  40 #endif
  41
  42 #else
  43
  44 #ifdef L_gcov_merge_add
  45 /* The profile merging function that just adds the counters.  It is given
  46    an array COUNTERS of N_COUNTERS old counters and it reads the same number
  47    of counters from the gcov file.  */
  48 void
  49 __gcov_merge_add (gcov_type *counters, unsigned n_counters)
  50 {
  51   for (; n_counters; counters++, n_counters--)
  52     *counters += gcov_get_counter ();
  53 }
  54 #endif /* L_gcov_merge_add */
  55
  56 #ifdef L_gcov_merge_ior
  57 /* The profile merging function that just adds the counters.  It is given
  58    an array COUNTERS of N_COUNTERS old counters and it reads the same number
  59    of counters from the gcov file.  */
  60 void
  61 __gcov_merge_ior (gcov_type *counters, unsigned n_counters)
  62 {
  63   for (; n_counters; counters++, n_counters--)
  64     *counters |= gcov_get_counter_target ();
  65 }
  66 #endif
  67
  68 #ifdef L_gcov_merge_time_profile
  69 /* Time profiles are merged so that minimum from all valid (greater than zero)
  70    is stored. There could be a fork that creates new counters. To have
  71    the profile stable, we chosen to pick the smallest function visit time.  */
  72 void
  73 __gcov_merge_time_profile (gcov_type *counters, unsigned n_counters)
  74 {
  75   unsigned int i;
  76   gcov_type value;
  77
  78   for (i = 0; i < n_counters; i++)
  79     {
  80       value = gcov_get_counter_target ();
  81
  82       if (value && (!counters[i] || value < counters[i]))
  83         counters[i] = value;
  84     }
  85 }
  86 #endif /* L_gcov_merge_time_profile */
  87
  88 #ifdef L_gcov_merge_single
  89
  90 static void
  91 merge_single_value_set (gcov_type *counters)
  92 {
  93   unsigned j;
  94   gcov_type value, counter;
  95
  96   /* First value is number of total executions of the profiler.  */
  97   gcov_type all = gcov_get_counter_ignore_scaling (-1);
  98   counters[0] += all;
  99   ++counters;
 100
 101   for (unsigned i = 0; i < GCOV_DISK_SINGLE_VALUES; i++)
 102     {
 103       value = gcov_get_counter_target ();
 104       counter = gcov_get_counter_ignore_scaling (-1);
 105
 106       if (counter == -1)
 107         {
 108           counters[1] = -1;
 109           /* We can't return as we need to read all counters.  */
 110           continue;
 111         }
 112       else if (counter == 0 || counters[1] == -1)
 113         {
 114           /* We can't return as we need to read all counters.  */
 115           continue;
 116         }
 117
 118       for (j = 0; j < GCOV_DISK_SINGLE_VALUES; j++)
 119         {
 120           if (counters[2 * j] == value)
 121             {
 122               counters[2 * j + 1] += counter;
 123               break;
 124             }
 125           else if (counters[2 * j + 1] == 0)
 126             {
 127               counters[2 * j] = value;
 128               counters[2 * j + 1] = counter;
 129               break;
 130             }
 131         }
 132
 133       /* We haven't found a free slot for the value, mark overflow.  */
 134       if (j == GCOV_DISK_SINGLE_VALUES)
 135         counters[1] = -1;
 136     }
 137 }
 138
 139 /* The profile merging function for choosing the most common value.
 140    It is given an array COUNTERS of N_COUNTERS old counters and it
 141    reads the same number of counters from the gcov file.  The counters
 142    are split into pairs where the members of the tuple have
 143    meanings:
 144
 145    -- the stored candidate on the most common value of the measured entity
 146    -- counter
 147    */
 148 void
 149 __gcov_merge_single (gcov_type *counters, unsigned n_counters)
 150 {
 151   gcc_assert (!(n_counters % GCOV_SINGLE_VALUE_COUNTERS));
 152
 153   for (unsigned i = 0; i < (n_counters / GCOV_SINGLE_VALUE_COUNTERS); i++)
 154     merge_single_value_set (counters + (i * GCOV_SINGLE_VALUE_COUNTERS));
 155 }
 156 #endif /* L_gcov_merge_single */
 157
 158 #endif /* inhibit_libc */