This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Identifying global state within GCC


On Thu, 2013-05-02 at 12:38 -0400, David Malcolm wrote:
> On Thu, 2013-05-02 at 07:20 -0600, Jeff Law wrote:
> > On 05/01/2013 02:32 PM, David Malcolm wrote:
> > > I had a go at writing a custom pass to try to locate places where GCC
> > > makes use of global state.
> > >
> > > You can see the pass here (which I implemented using gcc-python-plugin):
> > > https://gcc-python-plugin.readthedocs.org/en/latest/working-with-c.html#finding-global-variables
> > >
> > > A build log from recompiling gcc using this pass can be seen at:
> > > http://fedorapeople.org/~dmalcolm/gcc/2013-05-01/make.log
> > > (about 12MB in size; I killed it when I saw that stage 1 was done).
> > >
> > > I'm sure there are quite a few false positives in there.
> > >
> > > Hope this is helpful.  FWIW I had an earlier version of the pass which
> > > merely gave *declaration* sites for global variables, rather than all
> > > *uses* of such variables.
> > I wonder how useful it would be to filter out the source line 
> > information, then produce a histogram of which global state is hit the 
> > most often across the build.  That'd give us an interesting hitlist as 
> > we start trying to remove the global state.
> 
> A python script to do this (by parsing the logs) can be seen at:
> http://fedorapeople.org/~dmalcolm/gcc/2013-05-02/make-histogram.py
> 
> The results of running it can be seen at:
> http://fedorapeople.org/~dmalcolm/gcc/2013-05-02/histogram.txt
> (141k)

[sorry for also sending the large attachment; I rewrote the email and
meant to detach both attachments]


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]