Re: [Bug debug/42065] New: DWARF .debug_macinfo contains unused macros

[Andrew Pinski <pinskia at gmail dot com>]

Sent from my iPhone

On Nov 16, 2009, at 6:12 AM, "jan dot kratochvil at redhat dot com" <gcc-bugzilla@gcc.gnu.org 
> wrote:

> -g3 currently produces huge objects as it contains many unused macros.
> -g2 produces no macros debug info so GDB cannot provide its expansion.

That is by design and the reason why -g is -g2 by default ....



> There is no way to store just the used macros.
>
> (debuginfo compression driven by Roland McGrath may eliminate them but
> still...)
>
> While even a macro never used by a program can be helpful in most  
> cases IMO it
> is enough to provide the macro definitions touched by the code being  
> debugged.
>
> -feliminate-unused-debug-symbols -feliminate-unused-debug-types have  
> no effect.
>
> --- 
> --- 
> --- 
> ----------------------------------------------------------------------
> #define NOT used
> #define USED(x) x
> int main (void) { return USED (0); }
> --- 
> --- 
> --- 
> ----------------------------------------------------------------------
>
> Getting:
> gcc -g3 -o unusedmacro unusedmacro.c -Wall; readelf -wm unusedmacro
> DW_MACINFO_define - lineno : 1 macro : NOT used
> DW_MACINFO_define - lineno : 2 macro : USED(x) x
>
> or:
> gcc -g2 -o unusedmacro unusedmacro.c -Wall; readelf -wm unusedmacro
> <nothing printed>
>
> Expected output:
> gcc -g3 -o unusedmacro unusedmacro.c -Wall; readelf -wm unusedmacro
> DW_MACINFO_define - lineno : 2 macro : USED(x) x
>
>
> --
>           Summary: DWARF .debug_macinfo contains unused macros
>           Product: gcc
>           Version: 4.5.0
>            Status: UNCONFIRMED
>          Severity: minor
>          Priority: P3
>         Component: debug
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: jan dot kratochvil at redhat dot com
> GCC target triplet: x86_64-unknown-linux-gnu
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42065