I maintain the ccache package in Fedora, and I'm forwarding a bug report from https://bugzilla.redhat.com/show_bug.cgi?id=488863 here, this seems reproducible (at least the second part, I suspect the CORRECT/INCORRECT in the first one are swapped, i.e. the first one is actually incorrect, the latter correct) with 3.0pre0:

----

 Jan Kratochvil      2009-03-05 19:22:57 EST

Description of problem:
http://dwarf.freestandards.org/Dwarf3.pdf section 6.3.3 says the command-line
macros should have line number of their definition zero.
This is true for /usr/bin/gcc but in some cases `cache gcc' sets them non-zero.

Version-Release number of selected component (if applicable):
ccache-2.4-13.fc9.x86_64
gcc-4.3.2-7.x86_64

How reproducible:
Always.

CORRECT:
$ : >empty.c; ccache gcc -c -o empty.o empty.c -g3; readelf -wm empty.o \
  | grep __GNUC__
 DW_MACINFO_define - lineno : 3 macro : __GNUC__ 4

INCORRECT:
$ : >empty.c; /usr/bin/gcc -c -o empty.o empty.c -g3; readelf -wm empty.o \
  | grep __GNUC__
 DW_MACINFO_define - lineno : 0 macro : __GNUC__ 4

$ cat somefile.c
int
main (void)
{
  return 0;
}

CORRECT:
$ /usr/bin/gcc -c -o somefile.o somefile.c -Wall -g3;
$ /usr/bin/gcc -o somefile somefile.o -Wall
$ ~jkratoch/redhat/gdb-cvs-clean/gdb/gdb -q ./somefile
(gdb) start
Temporary breakpoint 1 at 0x400480: file somefile.c, line 4.
Starting program: /tmp/somefile 

Temporary breakpoint 1, main () at somefile.c:4
4         return 0;
(gdb) info macro __GNUC__
Defined at /tmp/somefile.c:0
#define __GNUC__ 4

INCORRECT:
$ ccache gcc -c -o somefile.o somefile.c -Wall -g3
$ gcc -o somefile somefile.o -Wall
$ ~jkratoch/redhat/gdb-cvs-clean/gdb/gdb -q ./somefile
(gdb) start
Temporary breakpoint 1 at 0x400480: file somefile.c, line 4.
Starting program: /tmp/somefile 

Temporary breakpoint 1, main () at somefile.c:4
4         return 0;
(gdb) info macro __GNUC__
Defined at /tmp/somefile.c:3
#define __GNUC__ 4
(gdb) l
1       int
2       main (void)
3       {
4         return 0;
5       }

Single-step compilation (without the `somefile.o' intermediate) does not
reproduce the problem.