C++11 provides support for generalized attributes, which can be seen as superset of Java annotations, as they can be applied not just to variables/functions, but also to statements, for example. But C++11 defines only syntax for generalized attributes, not means for user to define them.
This article gives good overview of generalized attributes: http://www.codesynthesis.com/~boris/blog/2012/04/18/cxx11-generalized-attributes/
GCC supports this feature from version 4.8, according to: http://gcc.gnu.org/projects/cxx0x.html
To implement support for user-defined attributes, compiler plugins are promising, especially based on high-level language integration, like https://fedorahosted.org/gcc-python-plugin/