perf report/top TUI: Support hotkey 'a' for annotation of unresolved addresses

In previous patch, we have supported the annotation functionality even
without symbols.

For this patch, it supports the hotkey 'a' on address in report view.
Note that, for branch mode, we only support the annotation for "branch
to" address.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200227043939.4403-4-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/browsers/hists.c

@@ -3061,21 +3061,45 @@ static int perf_evsel__hists_browse(struct evsel *evsel, int nr_events,
 				continue;
 			}
 
-			if (browser->selection == NULL ||
-			    browser->selection->sym == NULL ||
-			    browser->selection->map->dso->annotate_warned)
+			if (!browser->selection ||
+			    !browser->selection->map ||
+			    !browser->selection->map->dso ||
+			    browser->selection->map->dso->annotate_warned) {
 				continue;
+			}
 
-			if (symbol__annotation(browser->selection->sym)->src == NULL) {
-				ui_browser__warning(&browser->b, delay_secs * 2,
-						    "No samples for the \"%s\" symbol.\n\n"
-						    "Probably appeared just in a callchain",
-						    browser->selection->sym->name);
-				continue;
+			if (!browser->selection->sym) {
+				if (!browser->he_selection)
+					continue;
+
+				if (sort__mode == SORT_MODE__BRANCH) {
+					bi = browser->he_selection->branch_info;
+					if (!bi || !bi->to.ms.map)
+						continue;
+
+					actions->ms.sym = symbol__new_unresolved(bi->to.al_addr, bi->to.ms.map);
+					actions->ms.map = bi->to.ms.map;
+				} else {
+					actions->ms.sym = symbol__new_unresolved(browser->he_selection->ip,
+										 browser->selection->map);
+					actions->ms.map = browser->selection->map;
+				}
+
+				if (!actions->ms.sym)
+					continue;
+			} else {
+				if (symbol__annotation(browser->selection->sym)->src == NULL) {
+					ui_browser__warning(&browser->b, delay_secs * 2,
+						"No samples for the \"%s\" symbol.\n\n"
+						"Probably appeared just in a callchain",
+						browser->selection->sym->name);
+					continue;
+				}
+
+				actions->ms.map = browser->selection->map;
+				actions->ms.sym = browser->selection->sym;
 			}
 
-			actions->ms.map = browser->selection->map;
-			actions->ms.sym = browser->selection->sym;
 			do_annotate(browser, actions);
 			continue;
 		case 'P':