I had this bug just by enabling SAFE_HEAP and try to run HelloCpp sample in debug mode, with the very last emscripten commit in kripken/emscripten on incoming branch. I saw on [this post](https://groups.google.com/forum/#!topic/emscripten-discuss/Ekgx2BssN2M) that caiiiycuk could solve his segfault by disabling SAFE_HEAP.