1. A method of optimizing a program call between Instruction Set Architectures (ISA) in a system virtual machine, the method comprising: identifying a program call from a source process under a first ISA to a destination process under a second ISA different from the first ISA; augmenting a first region node of an intermediate representation of code comprising the source process of the program call with information configured to identify the first ISA; augmenting a second region node of an intermediate representation of code comprising the destination process of the program call with information configured to identify the second ISA; inlining the first region node and the second region node to optimize the program call; and emitting instructions for executing the optimized program call.