Re: PATCH: PR gas/10531: Strange assembler warning message on section group

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Wed, Aug 19, 2009 at 10:59 AM, Jim Wilson<wilson@codesourcery.com> wrote:
> On Tue, 2009-08-18 at 20:08 -0700, H.J. Lu wrote:
>> The main problem is we shouldn't identify a section just by section name only.
>
> I don't think that you understand the complete problem here. ?This patch
> will make the spurious warning message go away. ?This does not solve the
> problem that gas is emitting bogus debug info into a file that already
> contains debug info.
>
> This is trivial to prove with a small example. ?Put this into a C file
> int main (void) { asm (""); return 0; }
> Compile with "icc -c -g". ?Run "readelf -wl" on the .o file, and you
> will see that we have two directory tables, two file name tables, two
> line number tables, etc. ?The first set is OK, and was emitted by icc.
> The second set is bogus, and was emitted by gas.
>
> The reason that an unpatched gas can emit a bogus warning is that when
> we have comdat sections, gas accidentally emits the bogus debug info
> into a comdat section, corrupting the comdat section. ?Your patch fixes
> this by emitting the bogus debug info into a regular section. ?This is
> good, and necessary, but we are still emitting bogus debug info with
> your patch. ?I think this needs to be fixed also. ?We can probably fix
> this with a separate patch.
>
> If you want an example that generates the bogus warning, then try this
> inline int sub (void) { return 0; }
> int main (void) { asm (""); return sub (); }
> When I compile with "icc -O -g -c" I get a bogus warning. ?And running
> "readelf -wl" on the output shows again that we have bogus debug info
> emitted by gas, except now it is in a comdat section.
>


I didn't see the problem with my icc, using the patched
assembler. Can you provide main.s compiled by your icc?

Thanks.


-- 
H.J.