perf script: Show symbol offsets by default

perf script: Show symbol offsets by default

Since the ip shown for a symbol is now always a virtual address, it
becomes difficult to correlate this with objdump output and determine
the exact instruction address. So, we always show the offset from the
start of the symbol.

This can be verified on a powerpc64le system running Fedora 27 as
follows:

  # perf probe -a sys_write
  # perf record -e probe:sys_write -g ~/test

Before applying this patch:

  # perf script

  test  9710 [013] 95614.332431: probe:sys_write: (c0000000004025b0)
          c0000000004025b0 sys_write (/lib/modules/4.17.0-rc4+/build/vmlinux)
          c00000000000b9e0 system_call (/lib/modules/4.17.0-rc4+/build/vmlinux)
              7fffb70d8234 __GI___libc_write (/usr/lib64/libc-2.26.so)
              7fffb7052c74 _IO_file_write@@GLIBC_2.17 (/usr/lib64/libc-2.26.so)
                  5afc1818 [unknown] ([unknown])
              7fffb7051a60 new_do_write (/usr/lib64/libc-2.26.so)
              7fffb7054638 _IO_do_write@@GLIBC_2.17 (/usr/lib64/libc-2.26.so)
              7fffb7054bbc _IO_file_overflow@@GLIBC_2.17 (/usr/lib64/libc-2.26.so)
              7fffb7055a24 __overflow (/usr/lib64/libc-2.26.so)
              7fffb7044548 _IO_puts (/usr/lib64/libc-2.26.so)
                  10000440 main (/home/sandipan/test)
              7fffb6fe36a0 generic_start_main.isra.0 (/usr/lib64/libc-2.26.so)
              7fffb6fe3898 __libc_start_main (/usr/lib64/libc-2.26.so)
                         0 [unknown] ([unknown])
  ...

After applying this patch:

  # perf script

  test  9710 [013] 95614.332431: probe:sys_write: (c0000000004025b0)
          c0000000004025b0 sys_write+0x10 (/lib/modules/4.17.0-rc4+/build/vmlinux)
          c00000000000b9e0 system_call+0x58 (/lib/modules/4.17.0-rc4+/build/vmlinux)
              7fffb70d8234 __GI___libc_write+0x24 (/usr/lib64/libc-2.26.so)
              7fffb7052c74 _IO_file_write@@GLIBC_2.17+0x44 (/usr/lib64/libc-2.26.so)
                  5afc1818 [unknown] ([unknown])
              7fffb7051a60 new_do_write+0x90 (/usr/lib64/libc-2.26.so)
              7fffb7054638 _IO_do_write@@GLIBC_2.17+0x38 (/usr/lib64/libc-2.26.so)
              7fffb7054bbc _IO_file_overflow@@GLIBC_2.17+0x14c (/usr/lib64/libc-2.26.so)
              7fffb7055a24 __overflow+0x64 (/usr/lib64/libc-2.26.so)
              7fffb7044548 _IO_puts+0x218 (/usr/lib64/libc-2.26.so)
                  10000440 main+0x20 (/home/sandipan/test)
              7fffb6fe36a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
              7fffb6fe3898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
                         0 [unknown] ([unknown])
  ...

Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Link: http://lkml.kernel.org/r/20180517063326.6319-2-sandipan@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>