1 @c Copyright (C) 2014-2024 Free Software Foundation, Inc.
2 @c This is part of the GCC manual.
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27 @c Set file name and title for the man page.
28 @setfilename gcov-tool
29 @settitle offline gcda profile processing tool
33 @chapter @command{gcov-tool}---an Offline Gcda Profile Processing Tool
35 @command{gcov-tool} is a tool you can use in conjunction with GCC to
36 manipulate or process gcda profile files offline.
39 * Gcov-tool Intro:: Introduction to gcov-tool.
40 * Invoking Gcov-tool:: How to use gcov-tool.
44 @section Introduction to @command{gcov-tool}
45 @c man begin DESCRIPTION
47 @command{gcov-tool} is an offline tool to process gcc's gcda profile files.
49 Current gcov-tool supports the following functionalities:
53 merge two sets of profiles with weights.
56 read a stream of profiles with associated filenames and merge it with a set of
57 profiles with weights.
60 read one set of profile and rewrite profile contents. One can scale or
61 normalize the count values.
64 Examples of the use cases for this tool are:
67 Collect the profiles for different set of inputs, and use this tool to merge
68 them. One can specify the weight to factor in the relative importance of
72 Collect profiles from target systems without a filesystem (freestanding
73 environments). Merge the collected profiles with associated profiles
74 present on the host system. One can specify the weight to factor in the
75 relative importance of each input.
78 Rewrite the profile after removing a subset of the gcda files, while maintaining
79 the consistency of the summary and the histogram.
82 It can also be used to debug or libgcov code as the tools shares the majority
83 code as the runtime library.
86 Note that for the merging operation, this profile generated offline may
87 contain slight different values from the online merged profile. Here are
88 a list of typical differences:
92 histogram difference: This offline tool recomputes the histogram after merging
93 the counters. The resulting histogram, therefore, is precise. The online
94 merging does not have this capability -- the histogram is merged from two
95 histograms and the result is an approximation.
98 summary checksum difference: Summary checksum uses a CRC32 operation. The value
99 depends on the link list order of gcov-info objects. This order is different in
100 gcov-tool from that in the online merge. It's expected to have different
101 summary checksums. It does not really matter as the compiler does not use this
105 value profile counter values difference: Some counter values for value profile
106 are runtime dependent, like heap addresses. It's normal to see some difference
107 in these kind of counters.
112 @node Invoking Gcov-tool
113 @section Invoking @command{gcov-tool}
116 gcov-tool @r{[}@var{global-options}@r{]} SUB_COMMAND @r{[}@var{sub_command-options}@r{]} @var{profile_dir}
119 @command{gcov-tool} accepts the following options:
122 @c man begin SYNOPSIS
123 gcov-tool [@option{-v}|@option{--version}] [@option{-h}|@option{--help}]
125 gcov-tool merge [merge-options] @var{directory1} @var{directory2}
126 [@option{-o}|@option{--output} @var{directory}]
127 [@option{-v}|@option{--verbose}]
128 [@option{-w}|@option{--weight} @var{w1,w2}]
130 gcov-tool merge-stream [merge-stream-options] [@var{file}]
131 [@option{-v}|@option{--verbose}]
132 [@option{-w}|@option{--weight} @var{w1,w2}]
134 gcov-tool rewrite [rewrite-options] @var{directory}
135 [@option{-n}|@option{--normalize} @var{long_long_value}]
136 [@option{-o}|@option{--output} @var{directory}]
137 [@option{-s}|@option{--scale} @var{float_or_simple-frac_value}]
138 [@option{-v}|@option{--verbose}]
140 gcov-tool overlap [overlap-options] @var{directory1} @var{directory2}
141 [@option{-f}|@option{--function}]
142 [@option{-F}|@option{--fullname}]
143 [@option{-h}|@option{--hotonly}]
144 [@option{-o}|@option{--object}]
145 [@option{-t}|@option{--hot_threshold}] @var{float}
146 [@option{-v}|@option{--verbose}]
150 gpl(7), gfdl(7), fsf-funding(7), gcc(1), gcov(1) and the Info entry for
159 Display help about using @command{gcov-tool} (on the standard output), and
160 exit without doing any further processing.
164 Display the @command{gcov-tool} version number (on the standard output),
165 and exit without doing any further processing.
168 Merge two profile directories.
171 @item -o @var{directory}
172 @itemx --output @var{directory}
173 Set the output profile directory. Default output directory name is
174 @var{merged_profile}.
178 Set the verbose mode.
180 @item -w @var{w1},@var{w2}
181 @itemx --weight @var{w1},@var{w2}
182 Set the merge weights of the @var{directory1} and @var{directory2},
183 respectively. The default weights are 1 for both.
187 Collect profiles with associated filenames from a @emph{gcfn} and @emph{gcda}
188 data stream. Read the stream from the file specified by @var{file} or from
189 @file{stdin}. Merge the profiles with associated profiles in the host
190 filesystem. Apply the optional weights while merging profiles.
192 For the generation of a @emph{gcfn} and @emph{gcda} data stream on the target
193 system, please have a look at the @code{__gcov_filename_to_gcfn()} and
194 @code{__gcov_info_to_gcda()} functions declared in @code{#include <gcov.h>}.
199 Set the verbose mode.
201 @item -w @var{w1},@var{w2}
202 @itemx --weight @var{w1},@var{w2}
203 Set the merge weights of the profiles from the @emph{gcfn} and @emph{gcda} data
204 stream and the associated profiles in the host filesystem, respectively. The
205 default weights are 1 for both.
209 Read the specified profile directory and rewrite to a new directory.
212 @item -n @var{long_long_value}
213 @itemx --normalize <long_long_value>
214 Normalize the profile. The specified value is the max counter value
217 @item -o @var{directory}
218 @itemx --output @var{directory}
219 Set the output profile directory. Default output name is @var{rewrite_profile}.
221 @item -s @var{float_or_simple-frac_value}
222 @itemx --scale @var{float_or_simple-frac_value}
223 Scale the profile counters. The specified value can be in floating point value,
224 or simple fraction value form, such 1, 2, 2/3, and 5/3.
228 Set the verbose mode.
232 Compute the overlap score between the two specified profile directories.
233 The overlap score is computed based on the arc profiles. It is defined as
234 the sum of min (p1_counter[i] / p1_sum_all, p2_counter[i] / p2_sum_all),
235 for all arc counter i, where p1_counter[i] and p2_counter[i] are two
236 matched counters and p1_sum_all and p2_sum_all are the sum of counter
237 values in profile 1 and profile 2, respectively.
242 Print function level overlap score.
246 Print full gcda filename.
250 Only print info for hot objects/functions.
254 Print object level overlap score.
257 @itemx --hot_threshold <float>
258 Set the threshold for hot counter value.
262 Set the verbose mode.