embind doesn't always need the full std::type_info record. if EMSCRIPTEN_HAS_UNBOUND_TYPE_NAMES=0, then use a lighter type identifier. This shaves 175 KB off of our engine's minified JavaScript.

2 files changed, 55 insertions, 11 deletions

diff --git a/system/include/emscripten/bind.h b/system/include/emscripten/bind.h
index 872f279b..b4c5004e 100644
--- a/system/include/emscripten/bind.h
+++ b/system/include/emscripten/bind.h
@@ -813,7 +813,7 @@ namespace emscripten {
         // NOTE: this returns the class type, not the pointer type
         template<typename T>
         inline TYPEID getActualType(T* ptr) {
-            return reinterpret_cast<TYPEID>(&typeid(*ptr));
+            return getLightTypeID(*ptr);
         };
     }
 
diff --git a/system/include/emscripten/wire.h b/system/include/emscripten/wire.h
index 05b3ac33..c20e2f55 100644
--- a/system/include/emscripten/wire.h
+++ b/system/include/emscripten/wire.h
@@ -15,22 +15,66 @@
 #define EMSCRIPTEN_ALWAYS_INLINE __attribute__((always_inline))
 
 namespace emscripten {
+    #ifndef EMSCRIPTEN_HAS_UNBOUND_TYPE_NAMES
+    #define EMSCRIPTEN_HAS_UNBOUND_TYPE_NAMES 1
+    #endif
+
+
+    #if EMSCRIPTEN_HAS_UNBOUND_TYPE_NAMES
+    constexpr bool has_unbound_type_names = true;
+    #else
+    constexpr bool has_unbound_type_names = false;
+    #endif
+
     namespace internal {
         typedef void (*GenericFunction)();
 
-        typedef const struct _TYPEID* TYPEID;
+        typedef const struct _TYPEID {}* TYPEID;
+
+
+        // We don't need the full std::type_info implementation.  We
+        // just need a unique identifier per type and polymorphic type
+        // identification.
+        
+        template<typename T>
+        struct CanonicalizedID {
+            static TYPEID get() {
+                static _TYPEID c;
+                return &c;
+            }
+        };
+
+        template<typename T>
+        struct Canonicalized {
+            typedef typename std::remove_cv<typename std::remove_reference<T>::type>::type type;
+        };
+
+        template<typename T>
+        struct LightTypeID {
+            static TYPEID get() {
+                typedef typename Canonicalized<T>::type C;
+                if (has_unbound_type_names || std::is_polymorphic<C>::value) {
+                    return reinterpret_cast<TYPEID>(&typeid(C));
+                } else {
+                    return CanonicalizedID<C>::get();
+                }
+            }
+        };
+
+        template<typename T>
+        const TYPEID getLightTypeID(const T& value) {
+            typedef typename Canonicalized<T>::type C;
+            if (has_unbound_type_names || std::is_polymorphic<C>::value) {
+                return reinterpret_cast<TYPEID>(&typeid(value));
+            } else {
+                return LightTypeID<T>::get();
+            }
+        }
 
-        // This implementation is technically not legal, as it's not
-        // required that two calls to typeid produce the same exact
-        // std::type_info instance.  That said, it's likely to work
-        // given Emscripten compiles everything into one binary.
-        // Should it not work in the future: replace TypeID with an
-        // int, and store all TypeInfo we see in a map, allocating new
-        // TypeIDs as we add new items to the map.
         template<typename T>
         struct TypeID {
             static TYPEID get() {
-                return reinterpret_cast<TYPEID>(&typeid(T));
+                return LightTypeID<T>::get();
             }
         };
 
@@ -53,7 +97,7 @@ namespace emscripten {
         template<typename T>
         struct TypeID<AllowedRawPointer<T>> {
             static TYPEID get() {
-                return reinterpret_cast<TYPEID>(&typeid(T*));
+                return LightTypeID<T*>::get();
             }
         };