Don't compile sync_point if NDEBUG

Summary:
We don't really need sync_point.o if we're compiling with NDEBUG.

This diff depends on D17823

Test Plan: compiles

Reviewers: haobo, ljin, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17829

Makefile

@@ -17,7 +17,9 @@ ifeq ($(MAKECMDGOALS),shared_lib)
 PLATFORM_SHARED_LDFLAGS=-fPIC
 OPT += -DNDEBUG
 endif
+
 ifeq ($(MAKECMDGOALS),static_lib)
+PLATFORM_SHARED_LDFLAGS=-fPIC
 OPT += -DNDEBUG
 endif
 

util/sync_point.cc

@@ -5,6 +5,7 @@
 
 #include "util/sync_point.h"
 
+#ifndef NDEBUG
 namespace rocksdb {
 
 SyncPoint* SyncPoint::GetInstance() {
@@ -60,3 +61,4 @@ void SyncPoint::Process(const std::string& point) {
 }
 
 }  // namespace rocksdb
+#endif  // NDEBUG

util/sync_point.h

@@ -13,6 +13,10 @@
 
 namespace rocksdb {
 
+#ifdef NDEBUG
+#define TEST_SYNC_POINT(x)
+#else
+
 // This class provides facility to reproduce race conditions deterministically
 // in unit tests.
 // Developer could specify sync points in the codebase via TEST_SYNC_POINT.
@@ -72,8 +76,5 @@ class SyncPoint {
 // utilized to re-produce race conditions between threads.
 // See TransactionLogIteratorRace in db_test.cc for an example use case.
 // TEST_SYNC_POINT is no op in release build.
-#ifdef NDEBUG
-#define TEST_SYNC_POINT(x)
-#else
 #define TEST_SYNC_POINT(x) rocksdb::SyncPoint::GetInstance()->Process(x)
-#endif
+#endif  // NDEBUG