libgcc/libgcov-merge.c

   1 /* Routines required for instrumenting a program.  */
   2 /* Compile this one with gcc.  */
   3 /* Copyright (C) 1989-2024 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_ior
  37 void __gcov_merge_ior (gcov_type *counters  __attribute__ ((unused)),
  38                        unsigned n_counters __attribute__ ((unused))) {}
  39 #endif
  40
  41 #ifdef L_gcov_merge_topn
  42 void __gcov_merge_topn (gcov_type *counters  __attribute__ ((unused)),
  43                         unsigned n_counters __attribute__ ((unused))) {}
  44 #endif
  45
  46 #else
  47
  48 #ifdef L_gcov_merge_add
  49 /* The profile merging function that just adds the counters.  It is given
  50    an array COUNTERS of N_COUNTERS old counters and it reads the same number
  51    of counters from the gcov file.  */
  52 void
  53 __gcov_merge_add (gcov_type *counters, unsigned n_counters)
  54 {
  55   for (; n_counters; counters++, n_counters--)
  56     *counters += gcov_get_counter ();
  57 }
  58 #endif /* L_gcov_merge_add */
  59
  60 #ifdef L_gcov_merge_ior
  61 /* The profile merging function that just adds the counters.  It is given
  62    an array COUNTERS of N_COUNTERS old counters and it reads the same number
  63    of counters from the gcov file.  */
  64 void
  65 __gcov_merge_ior (gcov_type *counters, unsigned n_counters)
  66 {
  67   for (; n_counters; counters++, n_counters--)
  68     *counters |= gcov_get_counter_target ();
  69 }
  70 #endif
  71
  72 #ifdef L_gcov_merge_time_profile
  73 /* Time profiles are merged so that minimum from all valid (greater than zero)
  74    is stored. There could be a fork that creates new counters. To have
  75    the profile stable, we chosen to pick the smallest function visit time.  */
  76 void
  77 __gcov_merge_time_profile (gcov_type *counters, unsigned n_counters)
  78 {
  79   unsigned int i;
  80   gcov_type value;
  81
  82   for (i = 0; i < n_counters; i++)
  83     {
  84       value = gcov_get_counter_target ();
  85
  86       if (value && (!counters[i] || value < counters[i]))
  87         counters[i] = value;
  88     }
  89 }
  90 #endif /* L_gcov_merge_time_profile */
  91
  92 #ifdef L_gcov_merge_topn
  93
  94 /* The profile merging function for choosing the most common value.
  95    It is given an array COUNTERS of N_COUNTERS old counters and it
  96    reads the same number of counters from the gcov file.  The counters
  97    are split into pairs where the members of the tuple have
  98    meanings:
  99
 100    -- the stored candidate on the most common value of the measured entity
 101    -- counter
 102
 103    We use -TOTAL for situation when merging dropped some values.
 104    The information is used for -fprofile-reproducible flag.
 105    */
 106
 107 void
 108 __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
 109 {
 110   gcc_assert (!(n_counters % GCOV_TOPN_MEM_COUNTERS));
 111
 112   for (unsigned i = 0; i < (n_counters / GCOV_TOPN_MEM_COUNTERS); i++)
 113     {
 114       /* First value is number of total executions of the profiler.  */
 115       gcov_type all = gcov_get_counter_ignore_scaling (-1);
 116       gcov_type n = gcov_get_counter_ignore_scaling (-1);
 117
 118       unsigned full = all < 0;
 119       gcov_type *total = &counters[GCOV_TOPN_MEM_COUNTERS * i];
 120       *total += full ? -all : all;
 121
 122       for (unsigned j = 0; j < n; j++)
 123         {
 124           gcov_type value = gcov_get_counter_target ();
 125           gcov_type count = gcov_get_counter_ignore_scaling (-1);
 126
 127           // TODO: we should use atomic here
 128           full |= gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i,
 129                                        value, count, 0, 0);
 130         }
 131
 132       if (full)
 133         *total = -(*total);
 134     }
 135 }
 136 #endif /* L_gcov_merge_topn */
 137
 138 #endif /* inhibit_libc */