perf script python: Silence -Werror=maybe-uninitialized on gcc 5.3.0

Commit-ID:  39f54862a935e14a448cbd68d6a6bef68d026dbe
Gitweb:     http://git.kernel.org/tip/39f54862a935e14a448cbd68d6a6bef68d026dbe
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Tue, 12 Jul 2016 11:05:26 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Tue, 12 Jul 2016 15:20:39 -0300

perf script python: Silence -Werror=maybe-uninitialized on gcc 5.3.0

Sounds like a compiler bug, but to silence it, initialize those variables to NULL.

Noticed on:

Target: x86_64-alpine-linux-musl
Configured with: /home/buildozer/aports/main/gcc/src/gcc-5.3.0/configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --build=x86_64-alpine-linux-musl --host=x86_64-alpine-linux-musl --target=x86_64-alpine-linux-musl --with-pkgversion='Alpine 5.3.0' --enable-checking=release --disable-fixed-point --disable-libstdcxx-pch --disable-multilib --disable-nls --disable-werror --disable-symvers --enable-__cxa_atexit --enable-esp --enable-cloog-backend --enable-languages=c,c++,objc,java,fortran,ada --disable-libssp --disable-libmudflap --disable-libsanitizer --enable-shared --enable-threads --enable-tls --with-system-zlib
Thread model: posix
gcc version 5.3.0 (Alpine 5.3.0)

---
 tools/perf/util/scripting-engines/trace-event-python.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index ff13470..6ac6b7a 100644
@@ -273,7 +273,7 @@ static PyObject *get_field_numeric_entry(struct event_format *event,
 		struct format_field *field, void *data)
 {
 	bool is_array = field->flags & FIELD_IS_ARRAY;
-	PyObject *obj, *list = NULL;
+	PyObject *obj = NULL, *list = NULL;
 	unsigned long long val;
 	unsigned int item_size, n_items, i;
 

@@ -392,7 +392,7 @@ static void python_process_tracepoint(struct perf_sample *sample,
 				      struct addr_location *al)
 {
 	struct event_format *event = evsel->tp_format;
-	PyObject *handler, *context, *t, *obj, *callchain;
+	PyObject *handler, *context, *t, *obj = NULL, *callchain;
 	PyObject *dict = NULL;
 	static char handler_name[256];
 	struct format_field *field;