[PATCH V4 12/13] perf tools: remove nop at end of annotation

[Adrian Hunter <adrian.hunter@intel.com>]

When kcore is used for annotation, symbols do not
have correct sizes because they come from kallsyms.
That sometimes results in an extra nop being seen
after the end of a function.  Remove it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/annotate.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 4ab2f11..646e38d 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -830,6 +830,30 @@ static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
 	return 0;
 }
 
+static void delete_last_nop(struct symbol *sym)
+{
+	struct annotation *notes = symbol__annotation(sym);
+	struct list_head *list = &notes->src->source;
+	struct disasm_line *dl;
+
+	while (!list_empty(list)) {
+		dl = list_entry(list->prev, struct disasm_line, node);
+
+		if (dl->ins && dl->ins->ops) {
+			if (dl->ins->ops != &nop_ops)
+				return;
+		} else {
+			if (!strstr(dl->line, " nop ") &&
+			    !strstr(dl->line, " nopl ") &&
+			    !strstr(dl->line, " nopw "))
+				return;
+		}
+
+		list_del(&dl->node);
+		disasm_line__free(dl);
+	}
+}
+
 int symbol__annotate(struct symbol *sym, struct map *map, size_t privsize)
 {
 	struct dso *dso = map->dso;
@@ -923,6 +947,13 @@ fallback:
 		if (symbol__parse_objdump_line(sym, map, file, privsize) < 0)
 			break;
 
+	/*
+	 * kallsyms does not have symbol sizes so there may a nop at the end.
+	 * Remove it.
+	 */
+	if (dso__is_kcore(dso))
+		delete_last_nop(sym);
+
 	pclose(file);
 out_free_filename:
 	if (free_filename)
-- 
1.7.11.7