use static in FOLLY_SAFE_CHECK for clang+asan

Summary: Avoid enlarging data sections. The use of `static` causes data sections to be smaller in certain critical cases.

Reviewed By: cmds, luciang

Differential Revision: D27813138

fbshipit-source-id: 020b14927be5ac035d5f66e7cd652a58f8f820d0

folly/lang/SafeAssert.h

@@ -24,18 +24,27 @@
 #include <folly/Preprocessor.h>
 #include <folly/lang/CArray.h>
 
+#if __GNUC__ && !__clang__ && FOLLY_SANITIZE_ADDRESS
+//  gcc+asan has a bug that discards sections when using `static` below
+#define FOLLY_DETAIL_SAFE_CHECK_LINKAGE
+#else
+#define FOLLY_DETAIL_SAFE_CHECK_LINKAGE static
+#endif
+
 #define FOLLY_DETAIL_SAFE_CHECK_IMPL(d, p, expr, expr_s, ...)                  \
   if ((!d || ::folly::kIsDebug || ::folly::kIsSanitize) &&                     \
       !static_cast<bool>(expr)) {                                              \
-    constexpr auto __folly_detail_safe_assert_fun = __PRETTY_FUNCTION__;       \
-    constexpr ::folly::detail::safe_assert_arg __folly_detail_safe_assert_arg{ \
-        FOLLY_PP_STRINGIZE(expr_s),                                            \
-        __FILE__,                                                              \
-        __LINE__,                                                              \
-        __folly_detail_safe_assert_fun,                                        \
-        ::folly::detail::safe_assert_msg_types<decltype(                       \
-            ::folly::detail::safe_assert_msg_types_seq_of(                     \
-                __VA_ARGS__))>::value.data};                                   \
+    FOLLY_DETAIL_SAFE_CHECK_LINKAGE constexpr auto                             \
+        __folly_detail_safe_assert_fun = __PRETTY_FUNCTION__;                  \
+    FOLLY_DETAIL_SAFE_CHECK_LINKAGE constexpr ::folly::detail::safe_assert_arg \
+        __folly_detail_safe_assert_arg{                                        \
+            FOLLY_PP_STRINGIZE(expr_s),                                        \
+            __FILE__,                                                          \
+            __LINE__,                                                          \
+            __folly_detail_safe_assert_fun,                                    \
+            ::folly::detail::safe_assert_msg_types<decltype(                   \
+                ::folly::detail::safe_assert_msg_types_seq_of(                 \
+                    __VA_ARGS__))>::value.data};                               \
     ::folly::detail::safe_assert_terminate<p>(                                 \
         __folly_detail_safe_assert_arg, __VA_ARGS__);                          \
   }                                                                            \