1, What can stripcc do：
In order to be applicable for more platform and situations,
the projects based on C/C++ language often use many Conditional Compilation
Statements. Although they are more applicable, the readability of the source
code decreases at the same time. For example, there is a code fragment from
stunnel-4.20:
|
void stunnel_info(int raw) { sprintf(line, "stunnel " VERSION "
on " HOST " with %s", |
How do you think about the readability of it? Could you find
out the useful parts for a special platform easily like linux? Below is the
useful parts for linux(Fedora Core 3) produced by stripcc:
|
void stunnel_info(int raw) { |
It is more clearly when you read it again.
Sometimes a function may have different implementations for
different platform. This is widely used by some projects need to support
several platform, such as linux kernel. When you use a source navigation tool
like ctags or SourceInSight to read it, you will probably couldn't exactly
locate the code you want.
The goal of the stripcc is to resolve above problems. Simply
Speaking, using stripcc you can remove unused code from
your C/C++ based projects but the useful comments and original code style is
reserved.
2, How does stripcc work：
The principles of stripcc are easy to understand:
1, For each source file(such as *.c/*.h) in target
directory, insert GCC expanding Pre-Compiled Statements “#warning” to proper position.
2, Build entire project and analyse the output of the GCC.
3, According to the results of analysis to determine which
parts of the source file should be remained and which parts should be removed.
stripcc works reliably, it do not remove any useful source
code from your project. But please note that before you
using stripcc, the target project must be compiled successfully using “make”
or other commands.
3, How to use stripcc：
You need to download
the source code of stripcc, the stripcc is released under GPL version 2, you
can get it from http://sourceforge.net/projects/stripcc. Then decompress,
compile and install it. The default location of stripcc will be installed is
/usr/local/bin, you can change it by modify Makefile in stripcc source
directory or manually copy binary file(stripcc) to anywhere. But be sure that
the directory stripcc in is in your environment variable $PATH.
After install, you can use stripcc. Note
that before use it, you need back up your source code will be processed.
You will see the following output when you run stripcc with
the option "-h":
$ stripcc -h
Usage: stripcc <option(s)>
Remove CCs(Conditional Compilation Branches) which won't be
compiled from c/c++ source files under current directory.
The options are:
-c <str> Commands for build target
program, "make" is default
-m <str> Directory to run build commands,
current directory is default
-f Working
in fast mode (Experimental, NOT RECOMMENDED!)
-n Don't
verify after strip
-v Display
this program's version number
-h Display
this output
stripcc starts to support configuration file from version
0.2.0. It extremely improves the ability of the user to control the strip
process. stripcc try to read the configuration file from the current directory
of stripcc being called. The configuration file includes 5 sections:
[strip_exts] indicates the files identified by the extension
file name will be stripped, ".c" and ".h" are the default.
[strip_dirs] indicates the directories will be stripped
recursively, current directory "." is the default.
[dont_strip_dirs] indicates the directories shouldn't be
stripped.
[strip_files] indicates the files that were not restricted
by the extension file name will be stripped.
[dont_strip_files] indicates the files that shouldn't be
stripped.
You can refer to the sample file "stripcc.conf" in
stripcc's source package for the exact rule to write configuration file. Note that all paths of directory and file must use relative
one to the directory of "stripcc.conf" in and all paths must starts
with ".", like "./dir/file.c".
If stripcc can't find "stripcc.conf", it will
recursively strip all the files end with ".c" and ".h" in
the current directory.
We will take stunnel-4.21, lwip-0.5.3 and kernel-2.6.27.7
respectively for example to illustrate the usage of stripcc:
1,stunnel-4.21：
$ tar zxf stunnel-4.21.tar.gz
$ cd stunnel-4.21
$ ./configure
$ make
After "make" complete, you can call stripcc. it
will process all files in current directory recursively.
$ stripcc
o Getting a list of files
which will be stripped...
o Failed to open
config file(./stripcc.conf), use the default values.
o Backing up files...
o Adding
"#warning"...
o Try to build target, this
operation may takes a few minutes
o Restore files...
o Stripping files...
o Start to verify
o Done!
Green "Done!" indicates the strip process works
successfully.
2，lwip-
$ tar zxf lwip-
$ cd lwip-0.5.3
The main reason for taking lwip-0.5.3 as an example is that when
you compile lwip, you need to run "make" in the subdirectory
"proj/unixsim/".
$ cd proj/unixsim/
$ make
Then we back to the top directory after the build complete.
$ cd ..
$ cd ..
Run stripcc in the top directory and use "-m"
option to tell the stripcc call "make" in "proj/unixsim/":
$ stripcc -m "proj/unixsim"
o Getting a list of files
which will be stripped...
o Failed to open
config file(./stripcc.conf), use the default values.
o Backing up files...
o Adding
"#warning"...
o Try to build target, this
operation may takes a few minutes.
o Restore files...
o Stripping files...
o Start to verify
o Done!
3，kernel-
$ tar jxf linux-
$ cd linux-2.6.27.7
Choose the default configuration for x86:
$ make defconfig
$ make vmlinux
Then we get the total amount of the source code before
processing:
$ totalcode
totalline: 8410243
The total amount of the source code is about 8,410,000
lines. Then we can start to process, because the build command is not
"make" as the default of stripcc, so we need to use "-c"
option tell stripcc use "make ARCH=um" instead of "make".
$ stripcc -c "make vmlinux"
o Getting a list of files
which will be stripped...
o Failed to open
config file(./stripcc.conf), use the default values.
o Backing up files...
o Adding
"#warning"...
o Invalid source
line(./arch/mips/kernel/sync-r4k.c: 159).
o Try to build target, this
operation may takes a few minutes.
o Restore files...
o Stripping files...
o Start to verify
o Done!
Then we get the total amount of the source code after
processing:
$ totalcode
totalline: 1287399
The process cost about 4 times longer than the normal build.
The total amount of the remaining source code is only 1,187,399 lines, about
85% of the original source code is discarded. Now if you use ctags you will
feel more easy. In addition, because of we just used the default configuration
values provided by the kernel package, there are a lot of drivers and modules
we don't really need. If we disable those drivers/modules, we can easily reduce
the total amount of the remaining source code less than 400,000 lines.
4，Others：
1, What's new in stripcc-0.2.0?
a, Add configuration file(stripcc.conf)
support. Users can control the whole process of strip easily.
b, Unlike stripcc-0.1.*, new stripcc
will automatically ignore the syntax error in source files instead of report
error and quit.
c, Add fast strip mode, but
unfortunately, it works not as good as i ever thought, so this function is just
retained as an experimental feature.
2, Which Hardwares and OSs are stripcc supported?
Generally speaking, all hardware and
POSIX OS which GCC can running on are supported. The below is a list of them
which have been verified:
solaris/t1000:
-bash-3.00$
uname -a
SunOS t1000
5.10 Generic_118833-33 sun4v sparc SUNW,Sun-Fire-T1000 Solaris
-bash-3.00$
gcc --version
sparc-sun-solaris2.10-gcc (GCC) 4.0.3 (gccfss)
Copyright
(C) 2006 Free Software Foundation, Inc.
This is free
software; see the source for copying conditions. There is NO
warranty;
not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
solaris/x4100:
-bash-3.00$
uname -a
SunOS x4100
5.10 Generic_118855-33 i86pc i386 i86pc
-bash-3.00$
gcc --version
gcc (GCC)
3.4.3 (csl-sol210-3_4-branch+sol_rpath)
Copyright
(C) 2004 Free Software Foundation, Inc.
This is free
software; see the source for copying conditions. There is NO
warranty; not
even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
solaris/i386:
-bash-3.00$
uname -a
SunOS
solaris 5.10 Generic_118855-33 i86pc i386 i86pc Solaris
-bash-3.00$
gcc --version
gcc (GCC) 3.4.3
(csl-sol210-3_4-branch+sol_rpath)
Copyright
(C) 2004 Free Software Foundation, Inc.
This is free
software; see the source for copying conditions. There is NO
warranty;
not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
linux/x86_64:
dugang@ubuntu:~/test$ uname -a
Linux ubuntu
2.6.24-21-generic #1 SMP Tue Oct 21 23:09:30 UTC 2008 x86_64 GNU/Linux
dugang@ubuntu:~/test$ gcc --version
gcc (GCC)
4.2.4 (Ubuntu 4.2.4-1ubuntu3)
Copyright
(C) 2007 Free Software Foundation, Inc.
This is free
software; see the source for copying conditions. There is NO
warranty;
not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
freebsd/amd64:
-bash-2.05b$
uname -a
FreeBSD
freebsd.unix-center.net 6.2-RELEASE FreeBSD 6.2-RELEASE #0: Fri Jan 12 08:43:30
UTC 2007
root@portnoy.cse.buffalo.edu:/usr/obj/usr/src/sys/SMP amd64
-bash-2.05b$
gcc --version
gcc (GCC)
3.4.6 [FreeBSD] 20060305
Copyright
(C) 2006 Free Software Foundation, Inc.
This is free
software; see the source for copying conditions. There is NO
warranty; not
even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
aix/powerpc:
-bash-3.00$
uname -a
AIX aix 3 5
-bash-3.00$
gcc --version
gcc (GCC)
4.2.0
Copyright
(C) 2007 Free Software Foundation, Inc.
This is free
software; see the source for copying conditions. There is NO
warranty;
not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
linux/i386:
[duxg@l151
stripcc]$ uname -a
Linux l151
2.6.23.1-42.fc8 #1 SMP Tue Oct 30 13:55:12 EDT 2007 i686 i686 i386 GNU/Linux
[duxg@l151
stripcc]$ gcc --version
gcc (GCC)
4.1.2 20070925 (Red Hat 4.1.2-33)
Copyright
(C) 2006 Free Software Foundation, Inc.
This is free
software; see the source for copying conditions. There is NO
warranty;
not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
3, How about the C/C++ language standards support in
stripcc?
stripcc conforms to C99 and also support
some features extended by GCC. The only conflict with C99 is that C99 said the
newline character in multi-line comments(/* ... */) that should be retained,
but stripcc discards it as what was GCC done.
stripcc hasn't done anything specially
for C++ support.
5，Known problems：
1, Since
the limitation of the working principle of stripcc, There are some problems
when use stripcc to strip project which turned GCC option "-Werror"
on. so if stripcc report error, you should check the GCC's options of your
project first.
2, stripcc can't process the project which generates new
source file from other source file during the build time. The known projects
did this include GCC and Ethereal. There was no problem for those prjects which
generate source file from non-C source file, like from *.lex/*.y(lex/yacc's
source file).
6，Acknownagement：
I sincerely thank the people for stripcc use and helpful
suggestions, especially fangmz, harite.k, xishipan.
If you have any idea or comment on stripcc, let me know
please.
My EMail: dugang@188.com.
Thanks!