Compilation

In computing, compilation is the process of translating a program written in a high-level language into a form suitable for execution, typically machine code or an intermediate representation such as bytecode. A compiler performs this transformation in a series of stages and may produce a standalone executable or a library.

A typical compiler consists of a front end and a back end. The front end performs lexical analysis, parsing, and semantic analysis, building an intermediate representation and checking for correctness. The front end also resolves identifiers and types, and reports errors with locations.

The back end translates the intermediate representation into target code for a specific architecture, applies optimizations, and emits object code. The process may also include linking, which combines multiple object modules and libraries into an executable or shared library.

There are several forms of compilation. Ahead-of-time compilers generate native machine code before execution, while bytecode compilers emit instructions for a virtual machine. Transpilers translate between programming languages. Just-in-time compilers perform compilation at runtime, often within a virtual machine, enabling dynamic optimizations.

Compilation has a major impact on performance, portability, and toolchain design. Early compilers played a central role in the development of languages such as Fortran and C. Modern compilers emphasize optimizations, diagnostics, and platform support, and are a core component of many software development ecosystems. The process can affect debugging and reproducibility due to optimization and platform-specific behavior.