Fission is about improving debugger usability and link-time performance. We've designed DWARF extensions that allow us to split the bulk of the debug information from the object files, allowing us to substantially reduce total link time and the size of the linked binary. In addition, because the input files to the linker are significantly smaller, bandwidth needed for a distributed build system is also reduced. The final executable will contain an index of the debug information, allowing the debugger to locate the debug information on demand, so that debugger start-up time can also be reduced. A full description of the project is on the GCC wiki: http://gcc.gnu.org/wiki/DebugFission.