Välikoodia

Välikoodia, often translated as intermediate code or intermediate representation (IR), is a low-level, platform-independent code that is generated by a compiler or interpreter from a higher-level programming language. It acts as a stepping stone between the source code and the machine code that a computer's processor can directly execute. The primary purpose of välikoodia is to simplify the compilation process and enable optimizations.

By converting source code into välikoodia, compilers can decouple the front-end parsing and semantic analysis from the back-end code generation. This modularity allows for easier retargeting of compilers to different architectures. For instance, a compiler might first translate C++ code into a common välikoodia, and then use different back-ends to generate machine code for x86 processors, ARM processors, or other architectures.

Furthermore, välikoodia is an ideal format for performing various code optimizations. Many optimization techniques, such as dead code elimination, constant folding, and loop unrolling, are more effectively applied to this abstract representation than directly to the source code or the final machine code. These optimizations aim to improve the performance, reduce the memory footprint, or enhance the power efficiency of the compiled program.

Different compilers and programming languages utilize various forms of välikoodia. Examples include LLVM IR, Java bytecode, and the intermediate representation used in the .NET framework (CIL). Each of these has its own specific structure and instruction set, tailored to the needs of its respective compiler system.