Use constexpr for folly::dynamic::TypeInfo static fields

Summary: [Folly] Use constexpr for folly::dynamic::TypeInfo static fields

These things are compile-time values. So yeah.

Reviewed By: @​@​JoelMarcey

Differential Revision: D2466270

diff --git a/folly/dynamic-inl.h b/folly/dynamic-inl.h
index ff503c4a0d7350d18add9a3fbd8509383de883c5..8924fb3d9bff7641b10ced941fe84c532da5c7e8 100644 (file)
--- a/folly/dynamic-inl.h
+++ b/folly/dynamic-inl.h
@@ -612,24 +612,22 @@ inline void dynamic::pop_back() {
 
 //////////////////////////////////////////////////////////////////////
 
-template<class T> struct dynamic::TypeInfo {
-  static char const name[];
-  static Type const type;
-};
-
-#define FB_DEC_TYPE(T)                                      \
-  template<> char const dynamic::TypeInfo<T>::name[];       \
-  template<> dynamic::Type const dynamic::TypeInfo<T>::type
-
-FB_DEC_TYPE(void*);
-FB_DEC_TYPE(bool);
-FB_DEC_TYPE(fbstring);
-FB_DEC_TYPE(dynamic::Array);
-FB_DEC_TYPE(double);
-FB_DEC_TYPE(int64_t);
-FB_DEC_TYPE(dynamic::ObjectImpl);
-
-#undef FB_DEC_TYPE
+#define FOLLY_DYNAMIC_DEC_TYPEINFO(T, str, val) \
+  template <> struct dynamic::TypeInfo<T> { \
+    static constexpr const char* name = str; \
+    static constexpr dynamic::Type type = val; \
+  }; \
+  //
+
+FOLLY_DYNAMIC_DEC_TYPEINFO(void*,               "null",    dynamic::NULLT)
+FOLLY_DYNAMIC_DEC_TYPEINFO(bool,                "boolean", dynamic::BOOL)
+FOLLY_DYNAMIC_DEC_TYPEINFO(fbstring,            "string",  dynamic::STRING)
+FOLLY_DYNAMIC_DEC_TYPEINFO(dynamic::Array,      "array",   dynamic::ARRAY)
+FOLLY_DYNAMIC_DEC_TYPEINFO(double,              "double",  dynamic::DOUBLE)
+FOLLY_DYNAMIC_DEC_TYPEINFO(int64_t,             "int64",   dynamic::INT64)
+FOLLY_DYNAMIC_DEC_TYPEINFO(dynamic::ObjectImpl, "object",  dynamic::OBJECT)
+
+#undef FOLLY_DYNAMIC_DEC_TYPEINFO
 
 template<class T>
 T dynamic::asImpl() const {

diff --git a/folly/dynamic.cpp b/folly/dynamic.cpp
index d743bb2296831a541f756b714cfaf475522ee965..725cf56ad1bb0beaf90a2d38b8e24346d110af6a 100644 (file)
--- a/folly/dynamic.cpp
+++ b/folly/dynamic.cpp
@@ -20,19 +20,20 @@ namespace folly {
 
 //////////////////////////////////////////////////////////////////////
 
-#define DEF_TYPE(T, str, typen)                                 \
-  template<> char const dynamic::TypeInfo<T>::name[] = str;       \
-  template<> dynamic::Type const dynamic::TypeInfo<T>::type = typen
-
-DEF_TYPE(void*,               "null",    dynamic::NULLT);
-DEF_TYPE(bool,                "boolean", dynamic::BOOL);
-DEF_TYPE(fbstring,            "string",  dynamic::STRING);
-DEF_TYPE(dynamic::Array,      "array",   dynamic::ARRAY);
-DEF_TYPE(double,              "double",  dynamic::DOUBLE);
-DEF_TYPE(int64_t,             "int64",   dynamic::INT64);
-DEF_TYPE(dynamic::ObjectImpl, "object",  dynamic::OBJECT);
-
-#undef DEF_TYPE
+#define FOLLY_DYNAMIC_DEF_TYPEINFO(T) \
+  constexpr const char* dynamic::TypeInfo<T>::name; \
+  constexpr dynamic::Type dynamic::TypeInfo<T>::type; \
+  //
+
+FOLLY_DYNAMIC_DEF_TYPEINFO(void*)
+FOLLY_DYNAMIC_DEF_TYPEINFO(bool)
+FOLLY_DYNAMIC_DEF_TYPEINFO(fbstring)
+FOLLY_DYNAMIC_DEF_TYPEINFO(dynamic::Array)
+FOLLY_DYNAMIC_DEF_TYPEINFO(double)
+FOLLY_DYNAMIC_DEF_TYPEINFO(int64_t)
+FOLLY_DYNAMIC_DEF_TYPEINFO(dynamic::ObjectImpl)
+
+#undef FOLLY_DYNAMIC_DEF_TYPEINFO
 
 const char* dynamic::typeName() const {
   return typeName(type_);