23.8 Controlling which passes are being run

After the original gate function for a pass is called, its result - the gate status - is stored as an integer. Then the event PLUGIN_OVERRIDE_GATE is invoked, with a pointer to the gate status in the gcc_data parameter to the callback function. A nonzero value of the gate status means that the pass is to be executed. You can both read and write the gate status via the passed pointer.