Fix UB signed-integer-overflow in tracing test

Summary: [Folly] Fix UB `signed-integer-overflow` in tracing test.

Reviewed By: igorsugak

Differential Revision: D6922450

fbshipit-source-id: 0d9a338fdcf205987d88875aac4112666ca32b65

folly/tracing/test/StaticTracepointTest.cpp

@@ -417,7 +417,7 @@ TEST(StaticTracepoint, TestSemaphoreLocal) {
 FOLLY_SDT_DECLARE_SEMAPHORE(folly, test_semaphore_extern);
 
 TEST(StaticTracepoint, TestSemaphoreExtern) {
-  int v = folly::Random::rand32();
+  unsigned v = folly::Random::rand32();
   CHECK_EQ(v * v, folly::test::staticTracepointTestFunc(v));
   EXPECT_FALSE(FOLLY_SDT_IS_ENABLED(folly, test_semaphore_extern));
 }

folly/tracing/test/StaticTracepointTestModule.cpp

@@ -21,8 +21,8 @@ namespace test {
 
 FOLLY_SDT_DEFINE_SEMAPHORE(folly, test_semaphore_extern);
 
-int staticTracepointTestFunc(int v) {
-  int res = v * v;
+unsigned staticTracepointTestFunc(unsigned v) {
+  unsigned res = v * v;
   FOLLY_SDT_WITH_SEMAPHORE(folly, test_semaphore_extern, v, res);
   return res;
 }

folly/tracing/test/StaticTracepointTestModule.h

@@ -19,6 +19,6 @@
 namespace folly {
 namespace test {
 
-int staticTracepointTestFunc(int v);
+unsigned staticTracepointTestFunc(unsigned v);
 }
 } // namespace folly