1. An emulation apparatus for generating an emulator by combining a plurality of source components each describing a processing operation, the emulation apparatus comprising: a processor coupled to a memory, wherein: the memory stores policies each defined for different usage environment; and the processor executes the processing operation to generate the emulator by: obtaining, for each time period defined by the policy stored in the memory, a count of execution frequency of the processing operation performed by the emulator; rearranging and combining, for each policy stored in the memory and according to the count of execution frequency obtained in the obtaining, the source components to generate a source; and compiling, for each policy stored in the memory, the source generated at the rearranging and combining.