1 files changed, 18 insertions, 2 deletions
diff --git a/system/lib/embind/bind.cpp b/system/lib/embind/bind.cpp
index bc79876f..5e82bb7e 100755
--- a/system/lib/embind/bind.cpp
+++ b/system/lib/embind/bind.cpp
@@ -101,7 +101,7 @@ namespace emscripten {
             // __getDerivationPath returns an array of type_info pointers describing the derivation chain starting with
             // the derived type and proceeding toward (and ending with) the base type. Types are only included if they
             // appear on all possible derivation paths.
-            std::vector<int> __getDerivationPath(int dv, const int bs) { // todo: use emval array to pass return value??
+            std::vector<int> __getDerivationPath(int dv, const int bs) {
                 std::vector<std::vector<const __cxxabiv1::__class_type_info*>> paths;
 
                 const std::type_info* dv1 = (std::type_info*)dv;
@@ -176,11 +176,27 @@ namespace emscripten {
 
             // __getDynamicPointerType returns (for polymorphic types only!) the type of the instance actually
             // pointed to.
-            int EMSCRIPTEN_KEEPALIVE __getDynamicPointerType(int p) { // use size_t
+            int EMSCRIPTEN_KEEPALIVE __getDynamicPointerType(int p) {
                 void** vtable = *(void***)p;
                 return (int)static_cast<const std::type_info*>(vtable[-1]);
             }
 
+            // Calls to __dynamic_cast are generated by the compiler to implement dynamic_cast<>() -- its prototype is
+            // not available through any header file. It is called directly here because it allows run-time
+            // specification of the target pointer type (which can only be specified at compile time when using
+            // dynamic_cast<>().
+            void* __dynamic_cast(void*, const std::type_info*, const std::type_info*, int);
+
+            // __dynamicPointerCast performs a C++ dynamic_cast<>() operation, but allowing run-time specification of
+            // the from and to pointer types.
+            int EMSCRIPTEN_KEEPALIVE __dynamicPointerCast(int p, int to) {
+                int ret = (int)__staticPointerCast((void *)p, __getDynamicPointerType(p), to);
+                if (ret < 0) {
+                    return 0;
+                }
+                return ret;
+            }
+
             const char* EMSCRIPTEN_KEEPALIVE __typeName(int p) {
                 const std::type_info* ti = (const std::type_info*)p;
                 size_t nameLen = std::min(strlen(ti->name()), (unsigned int)1024);