tools/perf: Add '__rel_loc' event field parsing support

Add new '__rel_loc' dynamic data location attribute support.
This type attribute is similar to the '__data_loc' but records the
offset from the field itself.
The libtraceevent adds TEP_FIELD_IS_RELATIVE to the
'tep_format_field::flags' with TEP_FIELD_IS_DYNAMIC for'__rel_loc'.

Link: https://lkml.kernel.org/r/163757344810.510314.12449413842136229871.stgit@devnote2

Cc: Beau Belgrave <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Tom Zanussi <[e-mail]>
Signed-off-by: Masami Hiramatsu <[e-mail]>
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>

tools/perf/builtin-trace.c

···
 				offset = format_field__intval(field, sample, evsel->needs_swap);
 				syscall_arg.len = offset >> 16;
 				offset &= 0xffff;
+				if (field->flags & TEP_FIELD_IS_RELATIVE)
+					offset += field->offset + field->size;
 			}
 
 			val = (uintptr_t)(sample->raw_data + offset);

tools/perf/util/data-convert-bt.c

···
 		offset = tmp_val;
 		len = offset >> 16;
 		offset &= 0xffff;
+		if (flags & TEP_FIELD_IS_RELATIVE)
+			offset += fmtf->offset + fmtf->size;
 	}
 
 	if (flags & TEP_FIELD_IS_ARRAY) {

tools/perf/util/evsel.c

···
 	if (field->flags & TEP_FIELD_IS_DYNAMIC) {
 		offset = *(int *)(sample->raw_data + field->offset);
 		offset &= 0xffff;
+		if (field->flags & TEP_FIELD_IS_RELATIVE)
+			offset += field->offset + field->size;
 	}
 
 	return sample->raw_data + offset;

tools/perf/util/python.c

···
 			offset  = val;
 			len     = offset >> 16;
 			offset &= 0xffff;
+			if (field->flags & TEP_FIELD_IS_RELATIVE)
+				offset += field->offset + field->size;
 		}
 		if (field->flags & TEP_FIELD_IS_STRING &&
 		    is_printable_array(data + offset, len)) {

tools/perf/util/scripting-engines/trace-event-perl.c

···
 			if (field->flags & TEP_FIELD_IS_DYNAMIC) {
 				offset = *(int *)(data + field->offset);
 				offset &= 0xffff;
+				if (field->flags & TEP_FIELD_IS_RELATIVE)
+					offset += field->offset + field->size;
 			} else
 				offset = field->offset;
 			XPUSHs(sv_2mortal(newSVpv((char *)data + offset, 0)));

tools/perf/util/scripting-engines/trace-event-python.c

···
 				offset  = val;
 				len     = offset >> 16;
 				offset &= 0xffff;
+				if (field->flags & TEP_FIELD_IS_RELATIVE)
+					offset += field->offset + field->size;
 			}
 			if (field->flags & TEP_FIELD_IS_STRING &&
 			    is_printable_array(data + offset, len)) {

tools/perf/util/sort.c

···
 		tep_read_number_field(field, a->raw_data, &dyn);
 		offset = dyn & 0xffff;
 		size = (dyn >> 16) & 0xffff;
+		if (field->flags & TEP_FIELD_IS_RELATIVE)
+			offset += field->offset + field->size;
 
 		/* record max width for output */
 		if (size > hde->dynamic_len)