1. A computer implemented method comprising: receiving in a computing system having a processor that can operate in a first execution mode and a different second execution mode, a program that has an initial machine language instruction for execution by the processor in the first execution mode, wherein the initial machine language instruction, when executed by the processor in the first execution mode, performs a first operation; determining, by an instruction selector of a plugin configured to execute the program on the processor, that a portion of the initial machine language instruction, when the portion is interpreted by the processor as an instruction in the second execution mode, causes the processor to perform a second operation that is different from the first operation and that satisfies one or more risk criteria; in response, generating, by the instruction selector of the plugin, one or more alternative machine language instructions to replace the initial machine language instruction for execution by the processor in the first execution mode, wherein the one or more alternative machine language instructions, when interpreted by the processor as instructions in the first execution mode, cause the processor to perform a third operation that is similar to the first operation, and wherein the one or more alternative machine language instructions, when interpreted by the processor as one or more instructions in the different second execution mode, cause the processor to perform a fourth operation that is different from the second operation and that does not satisfy the one or more risk criteria of the second operation being performed by the processor when the portion of the initial machine language instruction is interpreted as an instruction in the second execution mode; and replacing, by the instruction selector of the plugin, the initial machine language instruction with the one or more alternative machine language instructions in the program.