Performance optimizations for emulators

One embodiment illustrated herein includes a method that may be practiced in a computing environment with a guest architecture running a native architecture system. The method includes acts for handling function calls. The method includes receiving a call to a hybrid binary, wherein the call is in a format for the guest architecture. The hybrid binary includes a native function compiled into a native architecture binary code using guest architecture source code, an interoperability thunk to handle an incompatibility between the guest architecture and the native architecture, and native host remapping metadata that is usable by an emulator to redirect native host callable targets to the interoperability thunk. The method further includes invoking the interoperability thunk to allow the native function in the hybrid binary to be executed natively on the native architecture system.