llvm dev - Mar 2012 - [LLVMdev] Dwarf info and .debug_pubnames section

Hi All,

I just enabled the generation of dwarf debugging information for Hexagon. It
did not require much save for the setting of a flag in MCAsmInfo.

However, now I see that the ".debug_pubnames" sections is not
generated. I
did read discussion about the section not really being useful for debuggers
in terms of accelerated access, but I have code that uses libdwarf to check
for global variables. The particular libdwarf API queries the
".debug_pubnames" This code is no longer functional because my LLVM
generated executables do not seem to have the .debug_pubnames sections. From
the discussion I did not gather that the sections would be removed
completely. Is that the case ?

TIA,
Pranav
 
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

On Mar 8, 2012, at 2:29 PM, Pranav Bhandarkar wrote:
> Hi All,
> 
> I just enabled the generation of dwarf debugging information for Hexagon.
It
> did not require much save for the setting of a flag in MCAsmInfo.
> 
> However, now I see that the ".debug_pubnames" sections is not
generated. I
> did read discussion about the section not really being useful for debuggers
> in terms of accelerated access, but I have code that uses libdwarf to check
> for global variables. The particular libdwarf API queries the
> ".debug_pubnames" This code is no longer functional because my
LLVM
> generated executables do not seem to have the .debug_pubnames sections.
From
> the discussion I did not gather that the sections would be removed
> completely. Is that the case ?
Nope, it's removed completely. No debugger that I know of uses it at all and
it's
useless for many reasons. Adding the code back in to generate it is possible
(it's
a fairly small commit that's easily reverted), but I see no reason to have
it generated
by default. What are you doing that involves looking for global variables in the
pubnames
section?

-eric

Hi Eric,
> Nope, it's removed completely. No debugger that I know of uses it at
> all and it's
> useless for many reasons. Adding the code back in to generate it is
> possible (it's
> a fairly small commit that's easily reverted), but I see no reason to
> have it generated
> by default. What are you doing that involves looking for global
> variables in the pubnames
> section?
>
Thanks for the information. After I sent out the email, I saw the patch you
reverted on viewVC. I have some proprietary code that looks at the debug
info in an executable using libdwarf; It queries the debug info on demand
with a variable name and uses dwarf_get_globals which, I believe, uses
.debug_pubnames.

I believe you made only one change to take out support for this section,
right ? I will revert that change and give it a go.

Thanks,
Pranav
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.