On Mon, Jan 6, 2020 at 11:52 AM Florian Weimer <fw@xxxxxxxxxxxxx> wrote:
>
> * William Tambe:
>
> > I would like for GCC to automatically generate instructions to
> > initialize global variables without having to manually create a
> > function with attribute((constructor)) to initialize those global
> > variables. In the example below from my previous email, GCC should
> > automatically generate instructions to initialize myglobal just like
> > it generates instructions to initialize mylocal; except those
> > instructions to initialize myglobal are to be generated within the
> > crti.S _init function:
> >
> > void myfunc (void) {}
> > void *myglobal = myfunc;
> > void main (void) {
> > void *mylocal = myfunc;
> > }
>
> I believe this would be best implemented in the link editor. It sees
> the relocations and can generate the appropriate code. However, for
Assembly generated to initialize myglobal is as follow:
.globl myglobal
.section .data.rel.local,"aw",@progbits
.align 8
.type myglobal, @object
.size myglobal, 8
myglobal:
.quad myfunc
Is it actually possible to create a link editor script that convert
the above assembly into instructions in the function _init ?
> position-indepedent code, usually a table-based approach with a
> minimal loader is typically used.
Could I have a pointer into the source code showing how it is implemented ?
