On Tue, Sep 23, 2014 at 10:00:00AM -0600, Jeff Law wrote: > On 09/23/14 08:34, Jakub Jelinek wrote: > >On Tue, Sep 23, 2014 at 05:54:37PM +0400, Ilya Enkovich wrote: > >>use fixed EBX at least until we make sure pseudo PIC doesn't harm debug > >>info generation. If we have such option then gcc.target/i386/pic-1.c and > > > >For debug info, it seems you are already handling this in > >delegitimize_address target hook, I'd suggest just building some very large > >shared library at -O2 -g -fpic on i?86 and either look at the > >sizes of .debug_info/.debug_loc sections with/without the patch, > >or use the locstat utility from elfutils (talk to Petr Machata if needed). > Can't hurt, but I really don't see how changing from a fixed to an > allocatable register is going to muck up debug info in any significant way.
What matters is if the delegitimize_address target hook is as efficient in delegitimization as before. E.g. if it previously matched only when seeing %ebx + gotoff or similar, and wouldn't match anything now, some vars could have debug locations including UNSPEC and be dropped on the floor. Jakub