libbacktrace: don't special case file 0

dwarf.c

@@ -3190,10 +3190,6 @@ read_line_program (struct backtrace_state *state, struct dwarf_data *ddata,
 		uint64_t fileno;
 
 		fileno = read_uleb128 (line_buf);
-		if (fileno == 0)
-		  filename = "";
-		else
-		  {
 		if (fileno >= hdr->filenames_count)
 		  {
 		    dwarf_buf_error (line_buf,
@@ -3204,7 +3200,6 @@ read_line_program (struct backtrace_state *state, struct dwarf_data *ddata,
 		  }
 		filename = hdr->filenames[fileno];
 	      }
-	      }
 	      break;
 	    case DW_LNS_set_column:
 	      read_uleb128 (line_buf);
@@ -3631,10 +3626,6 @@ read_function_entry (struct backtrace_state *state, struct dwarf_data *ddata,
 		case DW_AT_call_file:
 		  if (val.encoding == ATTR_VAL_UINT)
 		    {
-		      if (val.u.uint == 0)
-			function->caller_filename = "";
-		      else
-			{
 		      if (val.u.uint >= lhdr->filenames_count)
 			{
 			  dwarf_buf_error (unit_buf,
@@ -3643,9 +3634,7 @@ read_function_entry (struct backtrace_state *state, struct dwarf_data *ddata,
 					   0);
 			  return 0;
 			}
-			  function->caller_filename =
-			    lhdr->filenames[val.u.uint];
-			}
+		      function->caller_filename = lhdr->filenames[val.u.uint];
 		    }
 		  break;