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From: Nicholas N. <nj...@cs...> - 2008-02-06 21:11:31
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[Forwarding this from the valgrind-developers list in response to a query
from Robert Lieske about coverage tools]]
---------- Forwarded message ----------
Date: Mon, 4 Feb 2008 10:06:34 +1100 (EST)
From: Nicholas Nethercote <nj...@cs...>
To: Valgrind Developers <val...@li...>
Subject: [Valgrind-developers] Experimental Valgrind coverage tool
Hi,
I've written an experimental Valgrind coverage tool, called VCov. To try it
out, do this:
svn co svn://svn.valgrind.org/valgrind/branches/VCOV
Then build in the usual way (see the README file). To run it, use 'valgrind
--tool=exp-vcov <program>'.
It's pretty simple. It just records, for each line of source code, how many
instructions that were derived from that line were executed. It aggregates
data from multiple executions. It all goes in a file called "vcov.out".
To interpret the data, run this command:
perl exp-vcov/vc_annotate vcov.out
The output gives total, per-file and per-line coverage. An example:
--------------------------------------------------------------------------------
Total coverage
--------------------------------------------------------------------------------
100.0% ( 9 of 9 lines)
--------------------------------------------------------------------------------
Per-file coverage (files with the most unexecuted lines are shown first)
--------------------------------------------------------------------------------
100.0% ( 3 of 3 lines): /home/njn/grind/trunk9/b.h
100.0% ( 6 of 6 lines): /home/njn/grind/trunk9/a.c
--------------------------------------------------------------------------------
/home/njn/grind/trunk9/b.h
--------------------------------------------------------------------------------
-: 1:__inline__ int foo(void)
4: 2:{
2: 3: return 0;
4: 4:}
--------------------------------------------------------------------------------
/home/njn/grind/trunk9/a.c
--------------------------------------------------------------------------------
-: 1:#include <stdio.h>
-: 2:#include "b.h"
-: 3:
-: 4:int main(int argc, char* argv[])
20: 5:{
4: 6: if (argc < 2)
5: 7: printf("hello, world\n");
-: 8: else
4: 9: printf("hello, extended world\n");
-: 10:
2: 11: return foo();
4: 12:}
--------------------------------------------------------------------------------
Total coverage
--------------------------------------------------------------------------------
88.9% ( 8 of 9 lines)
--------------------------------------------------------------------------------
Per-file coverage (files with the most unexecuted lines are shown first)
--------------------------------------------------------------------------------
83.3% ( 5 of 6 lines): /home/njn/grind/trunk9/a.c
100.0% ( 3 of 3 lines): /home/njn/grind/trunk9/b.h
--------------------------------------------------------------------------------
/home/njn/grind/trunk9/b.h
--------------------------------------------------------------------------------
-: 1:__inline__ int foo(void)
2: 2:{
1: 3: return 0;
2: 4:}
--------------------------------------------------------------------------------
/home/njn/grind/trunk9/a.c
--------------------------------------------------------------------------------
-: 1:#include <stdio.h>
-: 2:#include "b.h"
-: 3:
-: 4:int main(int argc, char* argv[])
10: 5:{
2: 6: if (argc < 2)
5: 7: printf("hello, world\n");
-: 8: else
#####: 9: printf("hello, extended world\n");
-: 10:
1: 11: return foo();
2: 12:}
Non-executable lines are preceded with '-'. Lines that are executable but
not executed are preceded with '######', so they are obvious.
There are lots of shortcomings, but it gets the general idea across. Some
things worth noting:
- Files not compiled with -g won't have any results.
- You can use the --fresh=yes option to overwrite any prior coverage data.
- I plan to add the ability to change the name of the output file.
- Results with --trace-children will be suspect, as there is no file locking
done yet on the output file.
- I hope to add some kind of branch coverage info, at least for the
encountered branches.
- If your program has a file for which no code is executed, it won't get
included in the output.
- I plan to add the ability to be more selective about which files get
annotated (currently every file that has been executed and that can be
found is annotated).
Any comments are welcome.
Nick
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