-@c Copyright (C) 1996-2018 Free Software Foundation, Inc.
+@c Copyright (C) 1996-2020 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
@ignore
@c man begin COPYRIGHT
-Copyright @copyright{} 1996-2018 Free Software Foundation, Inc.
+Copyright @copyright{} 1996-2020 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
[@option{-c}|@option{--branch-counts}]
[@option{-d}|@option{--display-progress}]
[@option{-f}|@option{--function-summaries}]
- [@option{-i}|@option{--intermediate-format}]
+ [@option{-i}|@option{--json-format}]
[@option{-j}|@option{--human-readable}]
[@option{-k}|@option{--use-colors}]
[@option{-l}|@option{--long-file-names}]
[@option{-n}|@option{--no-output}]
[@option{-o}|@option{--object-directory} @var{directory|file}]
[@option{-p}|@option{--preserve-paths}]
+ [@option{-q}|@option{--use-hotness-colors}]
[@option{-r}|@option{--relative-only}]
[@option{-s}|@option{--source-prefix} @var{directory}]
+ [@option{-t}|@option{--stdout}]
[@option{-u}|@option{--unconditional-branches}]
[@option{-x}|@option{--hash-filenames}]
@var{files}
exit without doing any further processing.
@item -i
-@itemx --intermediate-format
-Output gcov file in an easy-to-parse intermediate text format that can
-be used by @command{lcov} or other tools. The output is a single
-@file{.gcov} file per @file{.gcda} file. No source code is required.
+@itemx --json-format
+Output gcov file in an easy-to-parse JSON intermediate format
+which does not require source code for generation. The JSON
+file is compressed with gzip compression algorithm
+and the files have @file{.gcov.json.gz} extension.
-The format of the intermediate @file{.gcov} file is plain text with
-one entry per line
+Structure of the JSON is following:
@smallexample
-version:@var{gcc_version}
-file:@var{source_file_name}
-function:@var{start_line_number},@var{end_line_number},@var{execution_count},@var{function_name}
-lcount:@var{line number},@var{execution_count},@var{has_unexecuted_block}
-branch:@var{line_number},@var{branch_coverage_type}
-
-Where the @var{branch_coverage_type} is
- notexec (Branch not executed)
- taken (Branch executed and taken)
- nottaken (Branch executed, but not taken)
+@{
+ "current_working_directory": @var{current_working_directory},
+ "data_file": @var{data_file},
+ "format_version": @var{format_version},
+ "gcc_version": @var{gcc_version}
+ "files": [@var{file}]
+@}
@end smallexample
-There can be multiple @var{file} entries in an intermediate gcov
-file. All entries following a @var{file} pertain to that source file
-until the next @var{file} entry. If there are multiple functions that
-start on a single line, then corresponding lcount is repeated multiple
-times.
+Fields of the root element have following semantics:
-Here is a sample when @option{-i} is used in conjunction with @option{-b} option:
+@itemize @bullet
+@item
+@var{current_working_directory}: working directory where
+a compilation unit was compiled
+
+@item
+@var{data_file}: name of the data file (GCDA)
+
+@item
+@var{format_version}: semantic version of the format
+
+@item
+@var{gcc_version}: version of the GCC compiler
+@end itemize
+
+Each @var{file} has the following form:
+
+@smallexample
+@{
+ "file": @var{file_name},
+ "functions": [@var{function}],
+ "lines": [@var{line}]
+@}
+@end smallexample
+
+Fields of the @var{file} element have following semantics:
+
+@itemize @bullet
+@item
+@var{file_name}: name of the source file
+@end itemize
+
+Each @var{function} has the following form:
+
+@smallexample
+@{
+ "blocks": @var{blocks},
+ "blocks_executed": @var{blocks_executed},
+ "demangled_name": "@var{demangled_name},
+ "end_column": @var{end_column},
+ "end_line": @var{end_line},
+ "execution_count": @var{execution_count},
+ "name": @var{name},
+ "start_column": @var{start_column}
+ "start_line": @var{start_line}
+@}
+@end smallexample
+
+Fields of the @var{function} element have following semantics:
+
+@itemize @bullet
+@item
+@var{blocks}: number of blocks that are in the function
+
+@item
+@var{blocks_executed}: number of executed blocks of the function
+
+@item
+@var{demangled_name}: demangled name of the function
+
+@item
+@var{end_column}: column in the source file where the function ends
+
+@item
+@var{end_line}: line in the source file where the function ends
+
+@item
+@var{execution_count}: number of executions of the function
+
+@item
+@var{name}: name of the function
+
+@item
+@var{start_column}: column in the source file where the function begins
+
+@item
+@var{start_line}: line in the source file where the function begins
+@end itemize
+
+Note that line numbers and column numbers number from 1. In the current
+implementation, @var{start_line} and @var{start_column} do not include
+any template parameters and the leading return type but that
+this is likely to be fixed in the future.
+
+Each @var{line} has the following form:
@smallexample
-version: 8.1.0 20180103
-file:tmp.cpp
-function:7,7,0,_ZN3FooIcEC2Ev
-function:7,7,1,_ZN3FooIiEC2Ev
-function:8,8,0,_ZN3FooIcE3incEv
-function:8,8,2,_ZN3FooIiE3incEv
-function:18,37,1,main
-lcount:7,0,1
-lcount:7,1,0
-lcount:8,0,1
-lcount:8,2,0
-lcount:18,1,0
-lcount:21,1,0
-branch:21,taken
-branch:21,nottaken
-lcount:23,1,0
-branch:23,taken
-branch:23,nottaken
-lcount:24,1,0
-branch:24,taken
-branch:24,nottaken
-lcount:25,1,0
-lcount:27,11,0
-branch:27,taken
-branch:27,taken
-lcount:28,10,0
-lcount:30,1,1
-branch:30,nottaken
-branch:30,taken
-lcount:32,1,0
-branch:32,nottaken
-branch:32,taken
-lcount:33,0,1
-branch:33,notexec
-branch:33,notexec
-lcount:35,1,0
-branch:35,taken
-branch:35,nottaken
-lcount:36,1,0
+@{
+ "branches": [@var{branch}],
+ "count": @var{count},
+ "line_number": @var{line_number},
+ "unexecuted_block": @var{unexecuted_block}
+ "function_name": @var{function_name},
+@}
@end smallexample
+Branches are present only with @var{-b} option.
+Fields of the @var{line} element have following semantics:
+
+@itemize @bullet
+@item
+@var{count}: number of executions of the line
+
+@item
+@var{line_number}: line number
+
+@item
+@var{unexecuted_block}: flag whether the line contains an unexecuted block
+(not all statements on the line are executed)
+
+@item
+@var{function_name}: a name of a function this @var{line} belongs to
+(for a line with an inlined statements can be not set)
+@end itemize
+
+Each @var{branch} has the following form:
+
+@smallexample
+@{
+ "count": @var{count},
+ "fallthrough": @var{fallthrough},
+ "throw": @var{throw}
+@}
+@end smallexample
+
+Fields of the @var{branch} element have following semantics:
+
+@itemize @bullet
+@item
+@var{count}: number of executions of the branch
+
+@item
+@var{fallthrough}: true when the branch is a fall through branch
+
+@item
+@var{throw}: true when the branch is an exceptional branch
+@end itemize
+
@item -j
@itemx --human-readable
-Write counts in human readable format (like 24k).
+Write counts in human readable format (like 24.6k).
@item -k
@itemx --use-colors
non-exceptional lines and cyan for exceptional. Same colors are used for
basic blocks with @option{-a} option.
-
@item -l
@itemx --long-file-names
Create long file names for included source files. For example, if the
components renamed to @samp{^}. This is useful if sourcefiles are in several
different directories.
+@item -q
+@itemx --use-hotness-colors
+
+Emit perf-like colored output for hot lines. Legend of the color scale
+is printed at the very beginning of the output file.
+
@item -r
@itemx --relative-only
Only output information about source files with a relative pathname
determining the output file names. Note that this prefix detection is
applied before determining whether the source file is absolute.
+@item -t
+@itemx --stdout
+Output to standard output instead of output files.
+
@item -u
@itemx --unconditional-branches
When branch probabilities are given, include those of unconditional branches.
@item -x
@itemx --hash-filenames
-By default, gcov uses the full pathname of the source files to to create
+When using @var{--preserve-paths},
+gcov uses the full pathname of the source files to create
an output filename. This can lead to long filenames that can overflow
filesystem limits. This option creates names of the form
@file{@var{source-file}##@var{md5}.gcov},
where the @var{source-file} component is the final filename part and
the @var{md5} component is calculated from the full mangled name that
-would have been used otherwise.
+would have been used otherwise. The option is an alternative
+to the @var{--preserve-paths} on systems which have a filesystem limit.
@end table
containing no code. Unexecuted lines are marked @samp{#####} or
@samp{=====}, depending on whether they are reachable by
non-exceptional paths or only exceptional paths such as C++ exception
-handlers, respectively. Given @samp{-a} option, unexecuted blocks are
+handlers, respectively. Given the @samp{-a} option, unexecuted blocks are
marked @samp{$$$$$} or @samp{%%%%%}, depending on whether a basic block
is reachable via non-exceptional or exceptional paths.
Executed basic blocks having a statement with zero @var{execution_count}
-end with @samp{*} character and are colored with magenta color with @option{-k}
-option. The functionality is not supported in Ada.
+end with @samp{*} character and are colored with magenta color with
+the @option{-k} option. This functionality is not supported in Ada.
Note that GCC can completely remove the bodies of functions that are
not needed -- for instance if they are inlined everywhere. Such functions
conventionally be rounded to 0% or 100% are instead printed as the
nearest non-boundary value.
-When using @command{gcov}, you must first compile your program with two
-special GCC options: @samp{-fprofile-arcs -ftest-coverage}.
+When using @command{gcov}, you must first compile your program
+with a special GCC option @samp{--coverage}.
This tells the compiler to generate additional information needed by
gcov (basically a flow graph of the program) and also includes
additional code in the object files for generating the extra profiling
is what you see when you use the basic @command{gcov} facility:
@smallexample
-$ g++ -fprofile-arcs -ftest-coverage tmp.cpp
+$ g++ --coverage tmp.cpp
$ a.out
$ gcov tmp.cpp -m
File 'tmp.cpp'
@smallexample
-: 0:Source:tmp.cpp
+ -: 0:Working directory:/home/gcc/testcase
-: 0:Graph:tmp.gcno
-: 0:Data:tmp.gcda
-: 0:Runs:1
@smallexample
-: 0:Source:tmp.cpp
+ -: 0:Working directory:/home/gcc/testcase
-: 0:Graph:tmp.gcno
-: 0:Data:tmp.gcda
-: 0:Runs:1
@smallexample
-: 0:Source:tmp.cpp
+ -: 0:Working directory:/home/gcc/testcase
-: 0:Graph:tmp.gcno
-: 0:Data:tmp.gcda
-: 0:Runs:1
@section Using @command{gcov} with GCC Optimization
If you plan to use @command{gcov} to help optimize your code, you must
-first compile your program with two special GCC options:
-@samp{-fprofile-arcs -ftest-coverage}. Aside from that, you can use any
+first compile your program with a special GCC option
+@samp{--coverage}. Aside from that, you can use any
other GCC options; but if you want to prove that every single line
in your program was executed, you should not compile with optimization
at the same time. On some machines the optimizer can eliminate some
If an executable loads a dynamic shared object via dlopen functionality,
@option{-Wl,--dynamic-list-data} is needed to dump all profile data.
+Profiling run-time library reports various errors related to profile
+manipulation and profile saving. Errors are printed into standard error output
+or @samp{GCOV_ERROR_FILE} file, if environment variable is used.
+In order to terminate immediately after an errors occurs
+set @samp{GCOV_EXIT_AT_ERROR} environment variable.
+That can help users to find profile clashing which leads
+to a misleading profile.
+
@c man end
@node Gcov Data Files
this option. It contains arc transition counts, value profile counts, and
some summary information.
-The full details of the file format is specified in @file{gcov-io.h},
-and functions provided in that header file should be used to access the
-coverage files.
+It is not recommended to access the coverage files directly.
+Consumers should use the intermediate format that is provided
+by @command{gcov} tool via @option{--json-format} option.
@node Cross-profiling
@section Data File Relocation to Support Cross-Profiling
projects / thirdparty / gcc.git / blobdiff