From 4a668c97a353e997102fe5b2a7c5dc83397204d7 Mon Sep 17 00:00:00 2001
From: Michele Caini <michele.caini@gmail.com>
Date: Wed, 2 Dec 2020 10:45:41 +0100
Subject: [PATCH] type_info: get around a nasty bug of clang < 9 when using
 libstdc++

---
 src/entt/config/config.h    | 16 +++-------
 src/entt/core/type_info.hpp | 63 ++++++++++++++++++++++---------------
 2 files changed, 42 insertions(+), 37 deletions(-)

diff --git a/src/entt/config/config.h b/src/entt/config/config.h
index 20d9c0323..291c781f7 100644
--- a/src/entt/config/config.h
+++ b/src/entt/config/config.h
@@ -42,20 +42,14 @@
 
 
 #ifndef ENTT_STANDARD_CPP
-#   if defined __clang__ || (defined __GNUC__ && __GNUC__ > 8)
-#       define ENTT_PRETTY_FUNCTION_CONSTEXPR
-#       define ENTT_PRETTY_FUNCTION __PRETTY_FUNCTION__
-#       define ENTT_PRETTY_FUNCTION_PREFIX '='
-#       define ENTT_PRETTY_FUNCTION_SUFFIX ']'
-#   elif defined __GNUC__
-#       define ENTT_PRETTY_FUNCTION __PRETTY_FUNCTION__
-#       define ENTT_PRETTY_FUNCTION_PREFIX '='
-#       define ENTT_PRETTY_FUNCTION_SUFFIX ']'
-#   elif defined _MSC_VER
-#       define ENTT_PRETTY_FUNCTION_CONSTEXPR
+#    if defined _MSC_VER
 #       define ENTT_PRETTY_FUNCTION __FUNCSIG__
 #       define ENTT_PRETTY_FUNCTION_PREFIX '<'
 #       define ENTT_PRETTY_FUNCTION_SUFFIX '>'
+#    elif defined __clang__ || defined __GNUC__
+#       define ENTT_PRETTY_FUNCTION __PRETTY_FUNCTION__
+#       define ENTT_PRETTY_FUNCTION_PREFIX '='
+#       define ENTT_PRETTY_FUNCTION_SUFFIX ']'
 #   endif
 #endif
 
diff --git a/src/entt/core/type_info.hpp b/src/entt/core/type_info.hpp
index aa871de94..212f0e9d2 100644
--- a/src/entt/core/type_info.hpp
+++ b/src/entt/core/type_info.hpp
@@ -31,7 +31,7 @@ struct ENTT_API type_seq final {
 
 
 template<typename Type>
-[[nodiscard]] constexpr auto type_name() ENTT_NOEXCEPT {
+[[nodiscard]] constexpr auto stripped_type_name() ENTT_NOEXCEPT {
 #if defined ENTT_PRETTY_FUNCTION
     std::string_view pretty_function{ENTT_PRETTY_FUNCTION};
     auto first = pretty_function.find_first_not_of(' ', pretty_function.find_first_of(ENTT_PRETTY_FUNCTION_PREFIX)+1);
@@ -43,6 +43,37 @@ template<typename Type>
 }
 
 
+template<typename Type, auto = stripped_type_name<Type>().find_first_of('.')>
+[[nodiscard]] static constexpr std::string_view type_name(int) ENTT_NOEXCEPT {
+    constexpr auto value = stripped_type_name<Type>();
+    return value;
+}
+
+
+template<typename Type>
+[[nodiscard]] static std::string_view type_name(char) ENTT_NOEXCEPT {
+    static const auto value = stripped_type_name<Type>();
+    return value;
+}
+
+
+template<typename Type, auto = stripped_type_name<Type>().find_first_of('.')>
+[[nodiscard]] static constexpr id_type type_hash(int) ENTT_NOEXCEPT {
+    constexpr auto stripped = stripped_type_name<Type>();
+    constexpr auto value = hashed_string::value(stripped.data(), stripped.size());
+    return value;
+}
+
+
+template<typename Type>
+[[nodiscard]] static id_type type_hash(char) ENTT_NOEXCEPT {
+    static const auto value = [](const auto stripped) {
+        return hashed_string::value(stripped.data(), stripped.size());
+    }(stripped_type_name<Type>());
+    return value;
+}
+
+
 }
 
 
@@ -79,22 +110,14 @@ struct type_hash final {
      * @brief Returns the numeric representation of a given type.
      * @return The numeric representation of the given type.
      */
-#if defined ENTT_PRETTY_FUNCTION_CONSTEXPR
+#if defined ENTT_PRETTY_FUNCTION
     [[nodiscard]] static constexpr id_type value() ENTT_NOEXCEPT {
-        constexpr auto stripped = internal::type_name<Type>();
-        constexpr auto value = hashed_string::value(stripped.data(), stripped.size());
-        return value;
-    }
-#elif defined ENTT_PRETTY_FUNCTION
-    [[nodiscard]] static id_type value() ENTT_NOEXCEPT {
-        static const auto value = [](const auto stripped) { return hashed_string::value(stripped.data(), stripped.size()); }(internal::type_name<Type>());
-        return value;
-    }
+        return internal::type_hash<Type>(0);
 #else
-    [[nodiscard]] static id_type value() ENTT_NOEXCEPT {
+    [[nodiscard]] static constexpr id_type value() ENTT_NOEXCEPT {
         return type_seq<Type>::value();
-    }
 #endif
+    }
 };
 
 
@@ -108,21 +131,9 @@ struct type_name final {
      * @brief Returns the name of a given type.
      * @return The name of the given type.
      */
-#if defined ENTT_PRETTY_FUNCTION_CONSTEXPR
     [[nodiscard]] static constexpr std::string_view value() ENTT_NOEXCEPT {
-        constexpr auto value = internal::type_name<Type>();
-        return value;
+        return internal::type_name<Type>(0);
     }
-#elif defined ENTT_PRETTY_FUNCTION
-    [[nodiscard]] static std::string_view value() ENTT_NOEXCEPT {
-        static const auto value = internal::type_name<Type>();
-        return value;
-    }
-#else
-    [[nodiscard]] static constexpr std::string_view value() ENTT_NOEXCEPT {
-        return internal::type_name<Type>();
-    }
-#endif
 };