инструмент тестирования покрытия (coverage testing tool)
Описание (Description)
gcov is a test coverage program. Use it in concert with GCC to
analyze your programs to help create more efficient, faster
running code and to discover untested parts of your program. You
can use gcov as a profiling tool to help discover where your
optimization efforts will best affect your code. You can also
use gcov along with the other profiling tool, gprof, to assess
which parts of your code use the greatest amount of computing
time.
Profiling tools help you analyze your code's performance. Using
a profiler such as gcov or gprof, you can find out some basic
performance statistics, such as:
* how often each line of code executes
* what lines of code are actually executed
* how much computing time each section of code uses
Once you know these things about how your code works when
compiled, you can look at each module to see which modules should
be optimized. gcov helps you determine where to work on
optimization.
Software developers also use coverage testing in concert with
testsuites, to make sure software is actually good enough for a
release. Testsuites can verify that a program works as expected;
a coverage program tests to see how much of the program is
exercised by the testsuite. Developers can then determine what
kinds of test cases need to be added to the testsuites to create
both better testing and a better final product.
You should compile your code without optimization if you plan to
use gcov because the optimization, by combining some lines of
code into one function, may not give you as much information as
you need to look for `hot spots' where the code is using a great
deal of computer time. Likewise, because gcov accumulates
statistics by line (at the lowest resolution), it works best with
a programming style that places only one statement on each line.
If you use complicated macros that expand to loops or to other
control structures, the statistics are less helpful---they only
report on the line where the macro call appears. If your complex
macros behave like functions, you can replace them with inline
functions to solve this problem.
gcov creates a logfile called sourcefile.gcov which indicates how
many times each line of a source file sourcefile.c has executed.
You can use these logfiles along with gprof to aid in fine-tuning
the performance of your programs. gprof gives timing information
you can use along with the information you get from gcov.
gcov works only on code compiled with GCC. It is not compatible
with any other profiling or test coverage mechanism.
