This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: Failures with exelib.exp testcase (was Re: minutes 2010-08-19)
On Mon, 2011-02-14 at 22:19 +0530, K.Prasad wrote:
> On Tue, Feb 08, 2011 at 02:13:35PM +0100, Mark Wielaard wrote:
> > On Thu, 2011-02-03 at 10:59 -0800, Roland McGrath wrote:
> > > What you need to do is:
> > >
> > > Elf64_Addr opd_addr;
> > > Dwarf_Addr bias;
> > > Elf_Scn *opd = dwfl_module_address_section (mod, &sym_addr, &bias);
> > > if (opd == NULL) ...;
> > > Elf_Data *data = elf_rawdata (opd, NULL);
> > > if (data == NULL) ...;
> > > Elf_Data in, out;
> > > out.d_buf = &final_addr;
> > > in.d_buf = (char *) data->d_buf + sym_addr;
> > > out.d_size = in.d_size = sizeof (Elf64_Addr);
> > > out.d_type = in.d_type = ELF_T_ADDR;
> > > if (elf64_xlatetom (elf, &out, &in, e_ident[EI_DATA]) == NULL) ...;
> > > sym_addr = opd_addr + bias;
> >
> > Thanks for the pseudocode example. Prasad, is that enough for you to
> > take a stab at hacking up a solution for the powerpc symbol lookup
> > issue?
> >
> So basically this would turn out into a piece of code to derive symbol
> address in, say dump_unwindsyms() in translate.cxx specific to
> __powerpc__ (or so I understand)?
Yes. The check should probably depend on whether the elf header has
e_machine == EM_PPC64 (since you could be running on ppc64, but
introspecting a ppc32 binary, which doesn't need these fixups).
> I'll give this a try and report what happens.
Thanks,
Mark