perf auxtrace: Add option to synthesize branch stack for regular events

There is an existing option to synthesize branch stacks for synthesized
events. Add a new option to synthesize branch stacks for regular events.

Signed-off-by: Adrian Hunter <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/itrace.txt

···
 		g	synthesize a call chain (use with i or x)
 		G	synthesize a call chain on existing event records
 		l	synthesize last branch entries (use with i or x)
+		L	synthesize last branch entries on existing event records
 		s       skip initial number of events
 
 	The default is all events i.e. the same as --itrace=ibxwpe,

tools/perf/builtin-inject.c

···
 
 			perf_header__clear_feat(&session->header,
 						HEADER_AUXTRACE);
-			if (inject->itrace_synth_opts.last_branch)
+			if (inject->itrace_synth_opts.last_branch ||
+			    inject->itrace_synth_opts.add_last_branch)
 				perf_header__set_feat(&session->header,
 						      HEADER_BRANCH_STACK);
 			evsel = perf_evlist__id2evsel_strict(session->evlist,

tools/perf/builtin-report.c

···
 	     !session->itrace_synth_opts->set))
 		sample_type |= PERF_SAMPLE_CALLCHAIN;
 
-	if (session->itrace_synth_opts->last_branch)
+	if (session->itrace_synth_opts->last_branch ||
+	    session->itrace_synth_opts->add_last_branch)
 		sample_type |= PERF_SAMPLE_BRANCH_STACK;
 
 	if (!is_pipe && !(sample_type & PERF_SAMPLE_CALLCHAIN)) {
···
 		goto error;
 	}
 
-	if (itrace_synth_opts.last_branch)
+	if (itrace_synth_opts.last_branch || itrace_synth_opts.add_last_branch)
 		has_br_stack = true;
 
 	if (has_br_stack && branch_call_mode)

tools/perf/util/auxtrace.c

···
 				synth_opts->callchain_sz = val;
 			}
 			break;
+		case 'L':
 		case 'l':
-			synth_opts->last_branch = true;
+			if (p[-1] == 'L')
+				synth_opts->add_last_branch = true;
+			else
+				synth_opts->last_branch = true;
 			synth_opts->last_branch_sz =
 					PERF_ITRACE_DEFAULT_LAST_BRANCH_SZ;
 			while (*p == ' ' || *p == ',')

tools/perf/util/auxtrace.h

···
  * @add_callchain: add callchain to existing event records
  * @thread_stack: feed branches to the thread_stack
  * @last_branch: add branch context to 'instruction' events
+ * @add_last_branch: add branch context to existing event records
  * @callchain_sz: maximum callchain size
  * @last_branch_sz: branch context size
  * @period: 'instructions' events period
···
 	bool			add_callchain;
 	bool			thread_stack;
 	bool			last_branch;
+	bool			add_last_branch;
 	unsigned int		callchain_sz;
 	unsigned int		last_branch_sz;
 	unsigned long long	period;

tools/perf/util/s390-cpumsf.c

···
 		itops->pwr_events || itops->errors ||
 		itops->dont_decode || itops->calls || itops->returns ||
 		itops->callchain || itops->thread_stack ||
-		itops->last_branch || itops->add_callchain;
+		itops->last_branch || itops->add_callchain ||
+		itops->add_last_branch;
 	if (!ison)
 		return true;
 	pr_err("Unsupported --itrace options specified\n");