rocksdb: Enable scan-build static analysis

Summary:
Added new target ##make analyze## into Makefile. This command runs clang static analyzer and builds the sources as ##make all##. The result report is put into ##$(RocksDbSourceRoot)/can_build_report/##

If the development environment is a Facebook devserver and ##ROCKSDB_NO_FBCODE## is not set, then scan-build is used from fbcode. If it is run not on a Facebook devserver, scan-build should be available in ##$PATH##. I'll add details to wiki how to install scan-build on a non Facebook devserver environment.

Test Plan:
Run the fallowing commands on a Facebook devserver and Mac OS, and ensure no build or test errors.

```
% make all check -j32
% make clean
% USE_CLANG=1 make all -j32
% make analyze
% USE_CLANG=1 make analyze
```

Reviewers: sdong, lgalanis, leveldb, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D32799

Makefile

@@ -238,7 +238,7 @@ endif  # PLATFORM_SHARED_EXT
 
 .PHONY: blackbox_crash_test check clean coverage crash_test ldb_tests package \
 	release tags valgrind_check whitebox_crash_test format static_lib shared_lib all \
-	dbg rocksdbjavastatic rocksdbjava install uninstall
+	dbg rocksdbjavastatic rocksdbjava install uninstall analyze
 
 all: $(LIBRARY) $(PROGRAMS) $(TESTS)
 
@@ -303,6 +303,10 @@ valgrind_check: all $(PROGRAMS) $(TESTS)
 		echo $$t $$((etime - stime)) >> $(VALGRIND_DIR)/valgrind_tests_times; \
 	done
 
+analyze:
+	$(MAKE) clean
+	$(CLANG_SCAN_BUILD) --use-analyzer=$(CLANG_ANALYZER) -o $(CURDIR)/scan_build_report $(MAKE) all -j32
+
 unity.cc:
 	$(shell (export ROCKSDB_ROOT="$(CURDIR)"; "$(CURDIR)/build_tools/unity" "$(CURDIR)/unity.cc"))
 
@@ -733,9 +737,11 @@ ifneq ($(MAKECMDGOALS),format)
 ifneq ($(MAKECMDGOALS),jclean)
 ifneq ($(MAKECMDGOALS),jtest)
 ifneq ($(MAKECMDGOALS),package)
+ifneq ($(MAKECMDGOALS),analyze)
 -include $(DEPFILES)
 endif
 endif
 endif
 endif
 endif
+endif

build_tools/build_detect_platform

@@ -75,6 +75,14 @@ if test -z "$TARGET_OS"; then
     TARGET_OS=`uname -s`
 fi
 
+if test -z "$CLANG_SCAN_BUILD"; then
+    CLANG_SCAN_BUILD=scan-build
+fi
+
+if test -z "$CLANG_ANALYZER"; then  
+    CLANG_ANALYZER=$(which clang++)
+fi
+
 COMMON_FLAGS="$COMMON_FLAGS ${CFLAGS}"
 CROSS_COMPILE=
 PLATFORM_CCFLAGS=
@@ -348,3 +356,5 @@ echo "JEMALLOC_LIB=$JEMALLOC_LIB" >> "$OUTPUT"
 echo "ROCKSDB_MAJOR=$ROCKSDB_MAJOR" >> "$OUTPUT"
 echo "ROCKSDB_MINOR=$ROCKSDB_MINOR" >> "$OUTPUT"
 echo "ROCKSDB_PATCH=$ROCKSDB_PATCH" >> "$OUTPUT"
+echo "CLANG_SCAN_BUILD=$CLANG_SCAN_BUILD" >> "$OUTPUT"
+echo "CLANG_ANALYZER=$CLANG_ANALYZER" >> "$OUTPUT"

build_tools/fbcode_config.sh

@@ -77,6 +77,10 @@ DEPS_INCLUDE="$SNAPPY_INCLUDE $ZLIB_INCLUDE $BZIP_INCLUDE $LZ4_INCLUDE $GFLAGS_I
 GCC_BASE="/mnt/gvfs/third-party2/gcc/1c67a0b88f64d4d9ced0382d141c76aaa7d62fba/4.9.x/centos6-native/1317bc4"
 STDLIBS="-L $GCC_BASE/lib64"
 
+CLANG_BASE="/mnt/gvfs/third-party2/clang/290704c112bf894bf4a30d7bbd1be81e34998473/dev"
+CLANG_ANALYZER="$CLANG_BASE/centos6-native/af4b1a0/bin/clang++"
+CLANG_SCAN_BUILD="$CLANG_BASE/src/clang/tools/scan-build/scan-build"
+
 if [ -z "$USE_CLANG" ]; then
   # gcc
   CC="$GCC_BASE/bin/gcc"
@@ -87,7 +91,6 @@ if [ -z "$USE_CLANG" ]; then
   CFLAGS+=" -isystem $LIBGCC_INCLUDE"
 else
   # clang 
-  CLANG_BASE="/mnt/gvfs/third-party2/clang/290704c112bf894bf4a30d7bbd1be81e34998473/dev"
   CLANG_INCLUDE="$CLANG_BASE/gcc-4.9-glibc-2.20/74c386f/lib/clang/dev/include/"
   CC="$CLANG_BASE/centos6-native/af4b1a0/bin/clang"
   CXX="$CLANG_BASE/centos6-native/af4b1a0/bin/clang++"
@@ -119,4 +122,4 @@ EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $ZLIB_LIBS $BZIP_LIBS $LZ4_LIBS $GFLAGS_LIBS"
 
 VALGRIND_VER="/mnt/gvfs/third-party2/valgrind/6c45ef049cbf11c2df593addb712cd891049e737/3.10.0/gcc-4.9-glibc-2.20/4230243/bin/"
 
-export CC CXX AR CFLAGS CXXFLAGS EXEC_LDFLAGS EXEC_LDFLAGS_SHARED VALGRIND_VER JEMALLOC_LIB JEMALLOC_INCLUDE
+export CC CXX AR CFLAGS CXXFLAGS EXEC_LDFLAGS EXEC_LDFLAGS_SHARED VALGRIND_VER JEMALLOC_LIB JEMALLOC_INCLUDE CLANG_ANALYZER CLANG_SCAN_BUILD