In my view, a compiler is a text transformation tool that converts high-level descriptive text languages into the format required by the target machine. Target machines typically have two specifications: operating system specifications and CPU specifications. As long as the final generated binary encoding satisfies both, it can run on the target machine. For example, Linux systems have ELF program loading specifications, while ARM64 manufacturers have CPU instruction specifications. As long as the CPU can recognize the binary encoding, it can command the CPU to perform the required computations.

In concrete implementation, it is usually necessary to convert high-level text languages into an Abstract Syntax Tree (AST), perform necessary detection and optimization based on the AST, and then convert it again into a lower-level Linear Intermediate Representation (LIR). After performing necessary detection and optimization on the LIR, the LIR can be converted into readable assembly instructions required by the target CPU. Further implementing an assembly instruction conversion tool converts the readable assembly instructions into binary encoding that the CPU can recognize.

Next, this set of binary encodings is wrapped into an executable file according to the operating system's requirements, ultimately obtaining a file that can run on the target device. Since a compiler is a text transformation tool, it can run this tool on any device - this is the essence of cross-compilation.