[tip:perf/core] perf script: Fix export of callchains with recursion in db-export

[tip-bot for Chris Phlipot]

Commit-ID:  83302e79b18f75266e4a44281e8432f61d57d441
Gitweb:     http://git.kernel.org/tip/83302e79b18f75266e4a44281e8432f61d57d441
Author:     Chris Phlipot <cphlipot0@xxxxxxxxx>
AuthorDate: Tue, 10 May 2016 20:26:49 -0700
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 11 May 2016 12:24:58 -0300

perf script: Fix export of callchains with recursion in db-export

When an IP with an unresolved symbol occurs in the callchain more than
once (ie. recursion), then duplicate symbols can be created because
the callchain nodes are never updated after they are first created.

To fix this issue we call dso__find_symbol whenever we encounter a NULL
symbol, in case we already added a symbol at that IP since we started
traversing the callchain.

This change prevents duplicate symbols from being exported when duplicate
IPs are present in the callchain.

Signed-off-by: Chris Phlipot <cphlipot0@xxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1462937209-6032-5-git-send-email-cphlipot0@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/db-export.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
index 8ca4186..8d96c80 100644
--- a/tools/perf/util/db-export.c
+++ b/tools/perf/util/db-export.c
@@ -326,6 +326,10 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
 		al.machine = machine;
 		al.addr = node->ip;
 
+		if (al.map && !al.sym)
+			al.sym = dso__find_symbol(al.map->dso, MAP__FUNCTION,
+						  al.addr);
+
 		db_ids_from_al(dbe, &al, &dso_db_id, &sym_db_id, &offset);
 
 		/* add node to the call path tree if it doesn't exist */