perf probe: Fix to get declared file name from clang DWARF5

Fix to get the declared file name even if it uses file index 0
in DWARF5, using custom die_get_decl_file() function.

Actually, the DWARF5 standard says file index 0 of the DW_AT_decl_file
is invalid(1), but there is a discussion and maybe this will be updated
[2].

Anyway, clang generates such DWARF5 file for the linux kernel. Thus it
must be handled.

Without this, 'perf probe' returns an error:

   $ ./perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
   Debuginfo analysis failed.
     Error: Failed to show lines.

With this, it can handle the case correctly:

  $ ./perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
  <vfs_read@$SRC_PATH/fs/read_write.c:10>

       11         ret = rw_verify_area(READ, file, pos, count);
       12         if (ret)
                           return ret;

[1] DWARF5 specification 2.14 says "The value 0 indicates that no source file has been specified.")
[2] http://wiki.dwarfstd.org/index.php?title=DWARF5_Line_Table_File_Numbers)

Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt (VMware) <[email protected]>
Link: https://lore.kernel.org/r/166731052936.2100653.13380621874859467731.stgit@devnote3
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions