[Bug debug/7580] incorrect/unfortunate DWARF-2 info for static const int class members

[dodji at gcc dot gnu dot org]

------- Comment #7 from dodji at gcc dot gnu dot org  2010-03-18 12:50 -------
Things have changed quite a bit in GCC 4.5  (trunk).

Now for the code:

class C
{
  static const int foo;
};

int
main()
{
  return 0;
}

GCC 4.5 will not generate any debug info for the class C at all, because it's
not used. The compiler does that to minimize the size of debug info.

Now if we write:

class C
{
    static const int foo;
};

int 
main()
{
  C c;
  return 0;
}

GCC generates debug info for C, and properly generates a DW_TAG_member for foo.
Note how we instantiate C in main, but don't reference C::foo in any way.

Here is a relevant DWARF portion of the assembly we get for this:

        .uleb128 0x2    # (DIE (0x2d) DW_TAG_class_type)
        .ascii "C\0"    # DW_AT_name
        .byte   0x1     # DW_AT_byte_size
        .byte   0x1     # DW_AT_decl_file (../../prtests/test.cc)
        .byte   0x2     # DW_AT_decl_line
        .long   0x49    # DW_AT_sibling
        .uleb128 0x3    # (DIE (0x37) DW_TAG_member)
        .ascii "foo\0"  # DW_AT_name
        .byte   0x1     # DW_AT_decl_file (../../prtests/test.cc)
        .byte   0x4     # DW_AT_decl_line
        .long   .LASF3  # DW_AT_MIPS_linkage_name: "_ZN1C3fooE"
        .long   0x49    # DW_AT_type
        .byte   0x1     # DW_AT_external
        .byte   0x1     # DW_AT_declaration
        .byte   0x0     # end of children of DIE 0x2d


So I think we can close this bug now.


-- 

dodji at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dodji at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2003-06-09 15:32:16         |2010-03-18 12:50:30
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=7580