gcc/doc/gcov-tool.texi

   1 @c Copyright (C) 2014 Free Software Foundation, Inc.
   2 @c This is part of the GCC manual.
   3 @c For copying conditions, see the file gcc.texi.
   4
   5 @ignore
   6 @c man begin COPYRIGHT
   7 Copyright @copyright{} 2014 Free Software Foundation, Inc.
   8
   9 Permission is granted to copy, distribute and/or modify this document
  10 under the terms of the GNU Free Documentation License, Version 1.3 or
  11 any later version published by the Free Software Foundation; with the
  12 Invariant Sections being ``GNU General Public License'' and ``Funding
  13 Free Software'', the Front-Cover texts being (a) (see below), and with
  14 the Back-Cover Texts being (b) (see below).  A copy of the license is
  15 included in the gfdl(7) man page.
  16
  17 (a) The FSF's Front-Cover Text is:
  18
  19      A GNU Manual
  20
  21 (b) The FSF's Back-Cover Text is:
  22
  23      You have freedom to copy and modify this GNU Manual, like GNU
  24      software.  Copies published by the Free Software Foundation raise
  25      funds for GNU development.
  26 @c man end
  27 @c Set file name and title for the man page.
  28 @setfilename gcov-tool
  29 @settitle offline gcda profile processing tool
  30 @end ignore
  31
  32 @node Gcov-tool
  33 @chapter @command{gcov-tool}---an Offline Gcda Profile Processing Tool
  34
  35 @command{gcov-tool} is a tool you can use in conjunction with GCC to
  36 manipulate or process gcda profile files offline.
  37
  38 @menu
  39 * Gcov-tool Intro::             Introduction to gcov-tool.
  40 * Invoking Gcov-tool::          How to use gcov-tool.
  41 @end menu
  42
  43 @node Gcov-tool Intro
  44 @section Introduction to @command{gcov-tool}
  45 @c man begin DESCRIPTION
  46
  47 @command{gcov-tool} is an offline tool to process gcc's gcda profile files.
  48
  49 Current gcov-tool supports the following functionalities:
  50
  51 @itemize @bullet
  52 @item
  53 merge two sets of profiles with weights.
  54
  55 @item
  56 read one set of profile and rewrite profile contents. One can scale or
  57 normalize the count values.
  58 @end itemize
  59
  60 Examples of the use cases for this tool are:
  61 @itemize @bullet
  62 @item
  63 Collect the profiles for different set of inputs, and use this tool to merge
  64 them. One can specify the weight to factor in the relative importance of
  65 each input.
  66
  67 @item
  68 Rewrite the profile after removing a subset of the gcda files, while maintaining
  69 the consistency of the summary and the histogram.
  70
  71 @item
  72 It can also be used to debug or libgcov code as the tools shares the majority
  73 code as the runtime library.
  74 @end itemize
  75
  76 Note that for the merging operation, this profile generated offline may
  77 contain slight different values from the online merged profile. Here are
  78 a list of typical differences:
  79
  80 @itemize @bullet
  81 @item
  82 histogram difference: This offline tool recomputes the histogram after merging
  83 the counters. The resulting histogram, therefore, is precise. The online
  84 merging does not have this capability -- the histogram is merged from two
  85 histograms and the result is an approximation.
  86
  87 @item
  88 summary checksum difference: Summary checksum uses a CRC32 operation. The value
  89 depends on the link list order of gcov-info objects. This order is different in
  90 gcov-tool from that in the online merge. It's expected to have different
  91 summary checksums. It does not really matter as the compiler does not use this
  92 checksum anywhere.
  93
  94 @item
  95 value profile counter values difference: Some counter values for value profile
  96 are runtime dependent, like heap addresses. It's normal to see some difference
  97 in these kind of counters.
  98 @end itemize
  99
 100 @c man end
 101
 102 @node Invoking Gcov-tool
 103 @section Invoking @command{gcov-tool}
 104
 105 @smallexample
 106 gcov-tool @r{[}@var{global-options}@r{]} SUB_COMMAND @r{[}@var{sub_command-options}@r{]} @var{profile_dir}
 107 @end smallexample
 108
 109 @command{gcov-tool} accepts the following options:
 110
 111 @ignore
 112 @c man begin SYNOPSIS
 113 gcov-tool [@option{-v}|@option{--version}] [@option{-h}|@option{--help}]
 114
 115 gcov-tool merge [merge-options] @var{directory1} @var{directory2}
 116      [@option{-v}|@option{--verbose}]
 117      [@option{-o}|@option{ --output} @var{directory}]
 118      [@option{-w}|@option{--weight} @var{w1,w2}]
 119
 120 gcov-tool rewrite [rewrite-options] @var{directory}
 121      [@option{-v}|@option{--verbose}]
 122      [@option{-o}|@option{--output} @var{directory}]
 123      [@option{-s}|@option{--scale} @var{float_or_simple-frac_value}]
 124      [@option{-n}|@option{--normalize} @var{long_long_value}]
 125
 126 gcov-tool overlap [overlap-options] @var{directory1} @var{directory2}
 127      [@option{-v}|@option{--verbose}]
 128      [@option{-h}|@option{--hotonly}]
 129      [@option{-f}|@option{--function}]
 130      [@option{-F}|@option{--fullname}]
 131      [@option{-o}|@option{--object}]
 132      [@option{-t}|@option{--hot_threshold}] @var{float}
 133
 134 @c man end
 135 @c man begin SEEALSO
 136 gpl(7), gfdl(7), fsf-funding(7), gcc(1), gcov(1) and the Info entry for
 137 @file{gcc}.
 138 @c man end
 139 @end ignore
 140
 141 @c man begin OPTIONS
 142 @table @gcctabopt
 143 @item -h
 144 @itemx --help
 145 Display help about using @command{gcov-tool} (on the standard output), and
 146 exit without doing any further processing.
 147
 148 @item -v
 149 @itemx --version
 150 Display the @command{gcov-tool} version number (on the standard output),
 151 and exit without doing any further processing.
 152
 153 @item merge
 154 Merge two profile directories.
 155
 156 @table @gcctabopt
 157 @item -v
 158 @itemx --verbose
 159 Set the verbose mode.
 160
 161 @item -o @var{directory}
 162 @itemx --output @var{directory}
 163 Set the output profile directory. Default output directory name is
 164 @var{merged_profile}.
 165
 166 @item -w @var{w1},@var{w2}
 167 @itemx --weight @var{w1},@var{w2}
 168 Set the merge weights of the @var{directory1} and @var{directory2},
 169 respectively. The default weights are 1 for both.
 170 @end table
 171
 172 @item rewrite
 173 Read the specified profile directory and rewrite to a new directory.
 174
 175 @table @gcctabopt
 176 @item -v
 177 @itemx --verbose
 178 Set the verbose mode.
 179
 180 @item -o @var{directory}
 181 @itemx --output @var{directory}
 182 Set the output profile directory. Default output name is @var{rewrite_profile}.
 183
 184 @item -s @var{float_or_simple-frac_value}
 185 @itemx --scale @var{float_or_simple-frac_value}
 186 Scale the profile counters. The specified value can be in floating point value,
 187 or simple fraction value form, such 1, 2, 2/3, and 5/3.
 188
 189 @item -n @var{long_long_value}
 190 @itemx --normalize <long_long_value>
 191 Normalize the profile. The specified value is the max counter value
 192 in the new profile.
 193 @end table
 194
 195 @item overlap
 196 Computer the overlap score between the two specified profile directories.
 197 The overlap score is computed based on the arc profiles. It is defined as
 198 the sum of min (p1_counter[i] / p1_sum_all, p2_counter[i] / p2_sum_all),
 199 for all arc counter i, where p1_counter[i] and p2_counter[i] are two
 200 matched counters and p1_sum_all and p2_sum_all are the sum of counter
 201 values in profile 1 and profile 2, respectively.
 202
 203 @table @gcctabopt
 204 @item -v
 205 @itemx --verbose
 206 Set the verbose mode.
 207
 208 @item -h
 209 @itemx --hotonly
 210 Only print info for hot objects/functions.
 211
 212 @item -f
 213 @itemx --function
 214 Print function level overlap score.
 215
 216 @item -F
 217 @itemx --fullname
 218 Print full gcda filename.
 219
 220 @item -o
 221 @itemx --object
 222 Print object level overlap score.
 223
 224 @item -t @var{float}
 225 @itemx --hot_threshold <float>
 226 Set the threshold for hot counter value.
 227 @end table
 228
 229 @end table
 230
 231 @c man end