On 05/24/2016 12:46 AM, Francesco Zappa Nardelli wrote: >> If you could produce a small object file.. > > Invoking readelf on /lib/x86_64-linux-gnu/libc.so.6 is enough to > observe this (I am on Ubuntu 14.04.3 LTS (GNU/Linux 3.13.0-68-generic > x86_64)): > > $ readelf -wf /lib/x86_64-linux-gnu/libc.so.6 (and search for S in the > augmentation string) > > 00002690 0000000000000014 00000000 CIE > Version: 1 > Augmentation: "zRS" > Code alignment factor: 1 > Data alignment factor: -8 > Return address column: 16 > Augmentation data: 1b > > DW_CFA_nop > DW_CFA_nop > DW_CFA_nop > DW_CFA_nop > DW_CFA_nop > DW_CFA_nop > > while readelf -wF gives: > > 00002690 0000000000000014 00000000 CIE "zRS" cf=1 df=-8 ra=16 > LOC CFA > 0000000000000000 rax+0
rax is the x86_64 64bit reg . As a 32bit x86 reg it is named eax. IMO this is an accidental side effect of the way dwarf.c is implemented in binutils. If printing eh_frame it won't print the CFA_nop but finishes up with a print of the resulting cfa reg which never got set so is zero. Zero results in printing rax+0. So I think this is just a simple bug in readelf. David Anderson _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
