Identifying global state within GCC

[Jeff Law]

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.

jeff