1. A computer system comprising: a processor; and a memory coupled to the processor, configured to provide the processor with a plurality of instructions including a plurality of garbage collection barrier instructions and a subsequent instruction that immediately follows the plurality of garbage collection barrier instructions; wherein the processor is configured to execute the plurality of garbage collection barrier instructions, including: evaluating a memory reference to determine a condition associated with the plurality of garbage collection barrier instructions; and in the event that the condition is met, while maintaining the same privilege level, saving information that is based at least in part on a current value of a program counter, and setting the program counter to correspond to a target location that is other than the subsequent instruction.