README-gcov_for_udev
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3Using GCC's code coverage tool, gcov, with udev
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5Leann Ogasawara <ogasawara@osdl.org>, April 2004
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8
9For more information on using gcov please see:
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11http://gcc.gnu.org/onlinedocs/gcc/Gcov.html
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13With that said, here is how to get code coverage analysis for udev files.
14Note that this was developed with udev version 024.
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16- Make sure you've installed udev and that it is working properly.
17 If you are having problems, refer to the README and HOWTO-udev_for_dev
18 documents in udev tarball.
19
20- execute make_gcov.sh from udev top level directory
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22 make gcov-all
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24 This will compile udev with gcov support. Basically make_gcov.sh will
25 run make but override the CFLAGS. It strips any optimization from
26 CFLAGS in order for gcov to get correct code coverage analysis. It will
27 also add the -fprofile-arcs and -ftest-coverage options which are the
28 necessary flags needed to use gcov.
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30 If you look into your udev directory and see that it has been polluted with
31 a bunch of *.gcno, *.gcda and *.gcov files. gcov creates and uses these files
32 to extract the code coverage info.
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34- After running make_gcov.sh you need to install udev again. So basically,
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36 su to root
37 make install
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39- Then execute some udev tasks. You can run some udev tests, reboot, or
40 do anything your little udev heart desires. Once you are satisfied, you
41 can now see how much udev code was covered. I personally recommend just
42 running test/udev-test.pl for starters.
43
44- To get the udev code coverage analysis, execute run_gcov.sh from udev top
45 level directory. You need to be root to do this.
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47 su to root
48 make udev_gcov.txt
49
50- This creates udev_gcov.txt in the udev top level directory which holds all
51 the code coverage information. To see an example of the code coverage info
52 after executing the udev-test.pl test, please see:
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54 http://developer.osdl.org/ogasawara/gcov_for_udev/udev_gcov.txt
55
56- Also, after having executed gcov on udev (ie executing run_gcov.sh) a
57 *.gcov file is created for every file which contained code that was
58 used. Looking at the *.gcov files, one will see what lines of code
59 were hit, and what lines were missed. For, example if code in udev-add.c
60 were executed, gcov then created a file called udev-add.c.gcov. And a
61 portion of udev-add.c.gov might look like:
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63 static int get_major_minor(struct sysfs_class_device *class_dev, struct udevice *udev)
64 95 {
65 95 struct sysfs_attribute *attr = NULL;
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67 95 attr = sysfs_get_classdev_attr(class_dev, "dev");
68 95 if (attr == NULL)
69 ###### goto error;
70 dbg("dev='%s'", attr->value);
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72 95 if (sscanf(attr->value, "%u:%u", &udev->major, &udev->minor) != 2)
73 ###### goto error;
74 dbg("found major=%d, minor=%d", udev->major, udev->minor);
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76 95 return 0;
77 error:
78 ###### return -1;
79 }
80
81 Any line of code that is preceded by a "######" implies that the code
82 was never hit during execution.
83
84- Once you are done with using gcov for udev and want to return to your
85 normal use of udev, run a regular 'make clean' on your udev directory.
86 Then just run a regular make and make install and you are back to normal:
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88 make clean all
89 su to root
90 make install
91