Re: [PATCH v4 1/3] systemtap/tapsets.cxx: Fix dwarfless probes on multiple static functions

[Hemant Kumar <hemant@linux.vnet.ibm.com>]

On 04/22/2015 07:10 PM, Mark Wielaard wrote:
> Hi Hemant,
>
> On Mon, 2015-04-20 at 15:59 +0530, Hemant Kumar wrote:
>> With multiple static functions with same names in an ELF and in absence
>> of dwarf, if we probe on one of the functions, then systemtap places
>> probe only on one static function ignoring the rest. This is because the
>> mapping between the symbol names and their func_info is a simple map
>> which doesn't allow insertion of another symbol with the same name.
>>
>> This patch fixes this issue by changing this map to a multimap which
>> allows duplicate entries for the same symbol name. lookup_symbol code
>> will return a set of func_info * instead of a single descriptor for a
>> function name.
>>
>> We also need to fix other areas in the code where lookup_symbol() and
>> lookup_symbol_address() are being called so as to look for a set of
>> func_info's and a list of Dwarf_Addr's respectively, instead of a single
>> descriptor.
> Looks good. I pushed this with one tiny change:

Thanks again.

> @@ -8242,6 +8242,8 @@ symbol_table::purge_syscall_stubs()
>     if (!addrs || addrs->empty())
>       return;
>     /* Highly unlikely that multiple symbols named "sys_ni_syscall" may exist */
> +  if (addrs->size() > 1)
> +    cerr << _("Multiple 'sys_ni_syscall' symbols found.");
>     Dwarf_Addr stub_addr = addrs->front();
>
> Just so that if this highly unlikely scenario does occur we get a
> warning something is fishy.
>

Right! looks good.

-- 
Thanks,
Hemant Kumar