Automatically transform pass-by-value semantics into pass-by-reference implementation

A non-transitory computer accessible memory medium that stores program instructions executable by a functional unit to perform operations comprising:

• compiling a program to generate output code, the compiling comprising:
• determining one or more program structures in the program containing one or more variables at one or more of the entry and exit of each of these program structures, wherein each variable specifies a value transfer between outside of a program structure and inside the program structure, and wherein each value transfer specifies a value transfer from one or more source variables to a destination variable;
• and
• implementing each of the value transfer operations in the output code, wherein, during operation based on the output code, the implementation of the value transfer operation includes:
• assigning each variable of the value transfer operation to a respective memory resource, thereby mapping the variables to the memory resources;
• determining a subset of the destination variables for which assigning the destination variable to a memory resource of a corresponding source variable does not disrupt the functionality of the program;
• and
• for the determined subset of the destination variables, dynamically changing the mapping, including assigning the destination variable to the memory resource of a first source variable of the one or more source variables, thereby transferring the value from the first source variable to the destination variable without copying the value between the memory resources.

A method for compiling a program to generate output code, the method comprising:

• by a processor:
• determining one or more program structures in the program containing one or more variables at the entry or exit of each of these program structures, wherein each variable at the entry or exit of a program structure specifies a value transfer between outside of a program structure and inside the program structure, and wherein each value transfer specifies a value transfer from one or more source variables to a destination variable;
• implementing each of the value transfer operations in the output code, wherein, during operation based on the output code, the implementation of the value transfer operation includes:
• assigning each variable of the value transfer operation to a respective memory resource, thereby mapping the variables to the memory resources;
• determining a subset of the destination variables for which assigning the destination variable to a memory resource of a corresponding source variable does not disrupt the functionality of the program;
• and
• for the subset of the destination variables, dynamically changing the mapping, including assigning the destination variable to the memory resource of a first source variable of the one or more source variables, thereby transferring the value from the first source variable to the destination variable without copying the value between the memory resources.