GNATbench provides integrated support for the SPARK language and tool-set. Results are displayed in dedicated SPARK output windows, and errors and warnings appear as usual in the Problems window. The SPARK tools are controlled via GNAT Project Properties, like all the other GNATbench tools.
Note that the SPARK menu commands are not visible if the SPARK executables themselves are not on your path, or if the SPARK feature has been manually disabled within Eclipse. See the SPARK tools' documentation for installing and setting up the SPARK tools themselves.