perf intel-pt: Add callchain to synthesized PEBS sample

Like other synthesized events, if there is also an Intel PT branch
trace, then a call stack can also be synthesized.  Add that.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190610072803.10456-12-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/intel-pt.c

@@ -1730,6 +1730,14 @@ static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
 			sample.time = tsc_to_perf_time(timestamp, &pt->tc);
 	}
 
+	if (sample_type & PERF_SAMPLE_CALLCHAIN &&
+	    pt->synth_opts.callchain) {
+		thread_stack__sample(ptq->thread, ptq->cpu, ptq->chain,
+				     pt->synth_opts.callchain_sz, sample.ip,
+				     pt->kernel_start);
+		sample.callchain = ptq->chain;
+	}
+
 	if (sample_type & PERF_SAMPLE_REGS_INTR &&
 	    items->mask[INTEL_PT_GP_REGS_POS]) {
 		u64 regs[sizeof(sample.intr_regs.mask)];