[PATCH v3 1/3] perf tools: Add from argument to dso__find_symbol_by_name()

[Namhyung Kim]

When a dso contains multiple symbols which have same name, current
dso__find_symbol_by_name() only finds an one of them and there's no way
to get the all symbols without going through the rbtree.

So add the new 'from' argument to dso__find_symbol_by_name() to remember
current symbol position and returns next symbol if it provided.  For the
first call the from should be NULL and the returned symbol should be
used as from to the next call.  It will return NULL if there's no symbol
that has given name anymore.

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
 tools/perf/util/map.c    | 13 ++++++++++---
 tools/perf/util/map.h    |  3 +++
 tools/perf/util/symbol.c | 41 ++++++++++++++++++++++++++++++++++++-----
 tools/perf/util/symbol.h |  2 +-
 4 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 62ca9f2607d5..01e2696ca8b5 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -301,8 +301,9 @@ struct symbol *map__find_symbol(struct map *map, u64 addr,
 	return dso__find_symbol(map->dso, map->type, addr);
 }
 
-struct symbol *map__find_symbol_by_name(struct map *map, const char *name,
-					symbol_filter_t filter)
+struct symbol *map__find_symbol_by_name_from(struct map *map, const char *name,
+					     symbol_filter_t filter,
+					     struct symbol *from)
 {
 	if (map__load(map, filter) < 0)
 		return NULL;
@@ -310,7 +311,13 @@ struct symbol *map__find_symbol_by_name(struct map *map, const char *name,
 	if (!dso__sorted_by_name(map->dso, map->type))
 		dso__sort_by_name(map->dso, map->type);
 
-	return dso__find_symbol_by_name(map->dso, map->type, name);
+	return dso__find_symbol_by_name(map->dso, map->type, name, from);
+}
+
+struct symbol *map__find_symbol_by_name(struct map *map, const char *name,
+					symbol_filter_t filter)
+{
+	return map__find_symbol_by_name_from(map, name, filter, NULL);
 }
 
 struct map *map__clone(struct map *map)
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 6951a9d42339..69acc58e6f9a 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -138,6 +138,9 @@ struct symbol *map__find_symbol(struct map *map,
 				u64 addr, symbol_filter_t filter);
 struct symbol *map__find_symbol_by_name(struct map *map, const char *name,
 					symbol_filter_t filter);
+struct symbol *map__find_symbol_by_name_from(struct map *map, const char *name,
+					     symbol_filter_t filter,
+					     struct symbol *from);
 void map__fixup_start(struct map *map);
 void map__fixup_end(struct map *map);
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index c24c5b83156c..e5800497ca61 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -396,6 +396,7 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
 					    const char *name)
 {
 	struct rb_node *n;
+	struct symbol_name_rb_node *s;
 
 	if (symbols == NULL)
 		return NULL;
@@ -403,7 +404,6 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
 	n = symbols->rb_node;
 
 	while (n) {
-		struct symbol_name_rb_node *s;
 		int cmp;
 
 		s = rb_entry(n, struct symbol_name_rb_node, rb_node);
@@ -414,10 +414,24 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
 		else if (cmp > 0)
 			n = n->rb_right;
 		else
-			return &s->sym;
+			break;
 	}
 
-	return NULL;
+	if (n == NULL)
+		return NULL;
+
+	/* return first symbol that has same name (if any) */
+	for (n = rb_prev(n); n; n = rb_prev(n)) {
+		struct symbol_name_rb_node *tmp;
+
+		tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
+		if (strcmp(tmp->sym.name, s->sym.name))
+			break;
+
+		s = tmp;
+	}
+
+	return &s->sym;
 }
 
 struct symbol *dso__find_symbol(struct dso *dso,
@@ -436,10 +450,27 @@ struct symbol *dso__next_symbol(struct symbol *sym)
 	return symbols__next(sym);
 }
 
+/*
+ * When @from is NULL, returns first symbol that matched with @name.
+ * Otherwise, returns next symbol after @from in case some (local) symbols
+ * have same name, or NULL.
+ */
 struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
-					const char *name)
+					const char *name, struct symbol *from)
 {
-	return symbols__find_by_name(&dso->symbol_names[type], name);
+	struct rb_node *n;
+	struct symbol_name_rb_node *s;
+
+	if (from == NULL)
+		return symbols__find_by_name(&dso->symbol_names[type], name);
+
+	s = container_of(from, struct symbol_name_rb_node, sym);
+	n = rb_prev(&s->rb_node);
+	if (n == NULL)
+		return NULL;
+
+	s = rb_entry(n, struct symbol_name_rb_node, rb_node);
+	return strcmp(s->sym.name, name) ? NULL : &s->sym;
 }
 
 void dso__sort_by_name(struct dso *dso, enum map_type type)
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 9d602e9c6f59..cd4f51d95bd0 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -230,7 +230,7 @@ int dso__load_kallsyms(struct dso *dso, const char *filename, struct map *map,
 struct symbol *dso__find_symbol(struct dso *dso, enum map_type type,
 				u64 addr);
 struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
-					const char *name);
+					const char *name, struct symbol *from);
 
 struct symbol *dso__first_symbol(struct dso *dso, enum map_type type);
 struct symbol *dso__next_symbol(struct symbol *sym);
-- 
2.2.1

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